National Library of Energy BETA

Sample records for ice nucleus abundance

  1. Development of a Mobile Ice Nucleus Counter

    SciTech Connect (OSTI)

    Kok, Gregory; Kulkarni, Gourihar

    2014-07-10

    An ice nucleus counter has been constructed. The instrument uses built-in refrigeration systems for wall cooling. A cascade refrigeration system will allow the cold wall to operate as low as -70 deg C, and a single stage system can operate the warm wall at -45 deg C. A unique optical particle counter has been constructed using polarization detection of the scattered light. This allows differentiation of the particles exiting the chamber to determine if they are ice or liquid.

  2. THE EFFECTS OF INITIAL ABUNDANCES ON NITROGEN IN PROTOPLANETARY DISKS

    SciTech Connect (OSTI)

    Schwarz, Kamber R.; Bergin, Edwin A.

    2014-12-20

    The dominant form of nitrogen provided to most solar system bodies is currently unknown, though available measurements show that the detected nitrogen in solar system rocks and ices is depleted with respect to solar abundances and the interstellar medium. We use a detailed chemical/physical model of the chemical evolution of a protoplanetary disk to explore the evolution and abundance of nitrogen-bearing molecules. Based on this model, we analyze how initial chemical abundances provided as either gas or ice during the early stages of disk formation influence which species become the dominant nitrogen bearers at later stages. We find that a disk with the majority of its initial nitrogen in either atomic or molecular nitrogen is later dominated by atomic and molecular nitrogen as well as NH{sub 3} and HCN ices, where the dominant species varies with disk radius. When nitrogen is initially in gaseous ammonia, it later becomes trapped in ammonia ice except in the outer disk where atomic nitrogen dominates. For a disk with the initial nitrogen in the form of ammonia ice, the nitrogen remains trapped in the ice as NH{sub 3} at later stages. The model in which most of the initial nitrogen is placed in atomic N best matches the ammonia abundances observed in comets. Furthermore, the initial state of nitrogen influences the abundance of N{sub 2}H{sup +}, which has been detected in protoplanetary disks. Strong N{sub 2}H{sup +} emission is found to be indicative of an N{sub 2} abundance greater than n{sub N{sub 2}}/n{sub H{sub 2}}>10{sup ?6} in addition to tracing the CO snow line. Our models also indicate that NO is potentially detectable, with lower N gas abundances leading to higher NO abundances.

  3. ARM - Measurement - Ice nuclei

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    : Ice nuclei Small particles around which ice particles form. Categories Cloud Properties Instruments The above measurement is considered scientifically relevant for the...

  4. Functionalized active-nucleus complex sensor

    DOE Patents [OSTI]

    Pines, Alexander; Wemmer, David E.; Spence, Megan; Rubin, Seth

    2003-11-25

    A functionalized active-nucleus complex sensor that selectively associates with one or more target species, and a method for assaying and screening for one or a plurality of target species utilizing one or a plurality of functionalized active-nucleus complexes with at least two of the functionalized active-nucleus complexes having an attraction affinity to different corresponding target species. The functionalized active-nucleus complex has an active-nucleus and a targeting carrier. The method involves functionalizing an active-nucleus, for each functionalized active-nucleus complex, by incorporating the active-nucleus into a macromolucular or molecular complex that is capable of binding one of the target species and then bringing the macromolecular or molecular complexes into contact with the target species and detecting the occurrence of or change in a nuclear magnetic resonance signal from each of the active-nuclei in each of the functionalized active-nucleus complexes.

  5. Abundant Biofuels | Open Energy Information

    Open Energy Info (EERE)

    Biofuels Jump to: navigation, search Name: Abundant Biofuels Place: Monterey, California Sector: Biofuels Product: Abundant Biofuels plans to develop biodiesel feedstock...

  6. Arctic ice islands

    SciTech Connect (OSTI)

    Sackinger, W.M.; Jeffries, M.O.; Lu, M.C.; Li, F.C.

    1988-01-01

    The development of offshore oil and gas resources in the Arctic waters of Alaska requires offshore structures which successfully resist the lateral forces due to moving, drifting ice. Ice islands are floating, a tabular icebergs, up to 60 meters thick, of solid ice throughout their thickness. The ice islands are thus regarded as the strongest ice features in the Arctic; fixed offshore structures which can directly withstand the impact of ice islands are possible but in some locations may be so expensive as to make oilfield development uneconomic. The resolution of the ice island problem requires two research steps: (1) calculation of the probability of interaction between an ice island and an offshore structure in a given region; and (2) if the probability if sufficiently large, then the study of possible interactions between ice island and structure, to discover mitigative measures to deal with the moving ice island. The ice island research conducted during the 1983-1988 interval, which is summarized in this report, was concerned with the first step. Monte Carlo simulations of ice island generation and movement suggest that ice island lifetimes range from 0 to 70 years, and that 85% of the lifetimes are less then 35 years. The simulation shows a mean value of 18 ice islands present at any time in the Arctic Ocean, with a 90% probability of less than 30 ice islands. At this time, approximately 34 ice islands are known, from observations, to exist in the Arctic Ocean, not including the 10-meter thick class of ice islands. Return interval plots from the simulation show that coastal zones of the Beaufort and Chukchi Seas, already leased for oil development, have ice island recurrences of 10 to 100 years. This implies that the ice island hazard must be considered thoroughly, and appropriate safety measures adopted, when offshore oil production plans are formulated for the Alaskan Arctic offshore. 132 refs., 161 figs., 17 tabs.

  7. Equations of state of ice VI and ice VII at high pressure and high temperature

    SciTech Connect (OSTI)

    Bezacier, Lucile; Hanfland, Michael; Journaux, Baptiste; Perrillat, Jean-Philippe; Cardon, Herv; Daniel, Isabelle

    2014-09-14

    High-pressure H{sub 2}O polymorphs among which ice VI and ice VII are abundant in the interiors of large icy satellites and exo-planets. Knowledge of the elastic properties of these pure H{sub 2}O ices at high-temperature and high-pressure is thus crucial to decipher the internal structure of icy bodies. In this study we assess for the first time the pressure-volume-temperature (PVT) relations of both polycrystalline pure ice VI and ice VII at high pressures and temperatures from 1 to 9 GPa and 300 to 450 K, respectively, by using in situ synchrotron X-ray diffraction. The PVT data are adjusted to a second-order Birch-Murnaghan equation of state and give V{sub 0} = 14.17(2) cm{sup 3}?mol{sup ?1}, K{sub 0} = 14.05(23) GPa, and ?{sub 0} = 14.6(14) 10{sup ?5} K{sup ?1} for ice VI and V{sub 0} = 12.49(1) cm{sup 3}?mol{sup ?1}, K{sub 0} = 20.15(16) GPa, and ?{sub 0} = 11.6(5) 10{sup ?5} K{sup ?1} for ice VII.

  8. Ice electrode electrolytic cell

    DOE Patents [OSTI]

    Glenn, D.F.; Suciu, D.F.; Harris, T.L.; Ingram, J.C.

    1993-04-06

    This invention relates to a method and apparatus for removing heavy metals from waste water, soils, or process streams by electrolytic cell means. The method includes cooling a cell cathode to form an ice layer over the cathode and then applying an electric current to deposit a layer of the heavy metal over the ice. The metal is then easily removed after melting the ice. In a second embodiment, the same ice-covered electrode can be employed to form powdered metals.

  9. ARM - Ice Cores

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    PastIce Cores Outreach Home Room News Publications Traditional Knowledge Kiosks Barrow, Alaska Tropical Western Pacific Site Tours Contacts Students Study Hall About ARM Global Warming FAQ Just for Fun Meet our Friends Cool Sites Teachers Teachers' Toolbox Lesson Plans Ice Cores Ice cores reveal information about the earth's climate history. The information from ice cores is both more precise and more compelling than from other sources. Accurate history of our earth's temperature and carbon

  10. Ice electrode electrolytic cell

    DOE Patents [OSTI]

    Glenn, David F. (Idaho Falls, ID); Suciu, Dan F. (Idaho Falls, ID); Harris, Taryl L. (Idaho Falls, ID); Ingram, Jani C. (Idaho Falls, ID)

    1993-01-01

    This invention relates to a method and apparatus for removing heavy metals from waste water, soils, or process streams by electrolytic cell means. The method includes cooling a cell cathode to form an ice layer over the cathode and then applying an electric current to deposit a layer of the heavy metal over the ice. The metal is then easily removed after melting the ice. In a second embodiment, the same ice-covered electrode can be employed to form powdered metals.

  11. METHANE AND NITROGEN ABUNDANCES ON PLUTO AND ERIS

    SciTech Connect (OSTI)

    Tegler, S. C.; Cornelison, D. M.; Abernathy, M. R.; Bovyn, M. J.; Burt, J. A.; Evans, D. E.; Maleszewski, C. K.; Thompson, Z.; Grundy, W. M.; Romanishin, W.; Vilas, F. E-mail: David.Cornelison@nau.ed E-mail: wjr@nhn.ou.ed

    2010-12-10

    We present spectra of Eris from the MMT 6.5 m Telescope and Red Channel Spectrograph (5700-9800 A, 5 A pixel{sup -1}) on Mt. Hopkins, AZ, and of Pluto from the Steward Observatory 2.3 m Telescope and Boller and Chivens Spectrograph (7100-9400 A, 2 A pixel{sup -1}) on Kitt Peak, AZ. In addition, we present laboratory transmission spectra of methane-nitrogen and methane-argon ice mixtures. By anchoring our analysis in methane and nitrogen solubilities in one another as expressed in the phase diagram of Prokhvatilov and Yantsevich, and comparing methane bands in our Eris and Pluto spectra and methane bands in our laboratory spectra of methane and nitrogen ice mixtures, we find Eris' bulk methane and nitrogen abundances are {approx}10% and {approx}90% and Pluto's bulk methane and nitrogen abundances are {approx}3% and {approx}97%. Such abundances for Pluto are consistent with values reported in the literature. It appears that the bulk volatile composition of Eris is similar to the bulk volatile composition of Pluto. Both objects appear to be dominated by nitrogen ice. Our analysis also suggests, unlike previous work reported in the literature, that the methane and nitrogen stoichiometry is constant with depth into the surface of Eris. Finally, we point out that our Eris spectrum is also consistent with a laboratory ice mixture consisting of 40% methane and 60% argon. Although we cannot rule out an argon-rich surface, it seems more likely that nitrogen is the dominant species on Eris because the nitrogen ice 2.15 {mu}m band is seen in spectra of Pluto and Triton.

  12. THE STICKINESS OF MICROMETER-SIZED WATER-ICE PARTICLES

    SciTech Connect (OSTI)

    Gundlach, B.; Blum, J.

    2015-01-01

    Water ice is one of the most abundant materials in dense molecular clouds and in the outer reaches of protoplanetary disks. In contrast to other materials (e.g., silicates), water ice is assumed to be stickier due to its higher specific surface energy, leading to faster or more efficient growth in mutual collisions. However, experiments investigating the stickiness of water ice have been scarce, particularly in the astrophysically relevant micrometer-sized region and at low temperatures. In this work, we present an experimental setup to grow aggregates composed of ?m-sized water-ice particles, which we used to measure the sticking and erosion thresholds of the ice particles at different temperatures between 114 K and 260 K. We show with our experiments that for low temperatures (below ?210 K), ?m-sized water-ice particles stick below a threshold velocity of 9.6 m s{sup 1}, which is approximately 10times higher than the sticking threshold of ?m-sized silica particles. Furthermore, erosion of the grown ice aggregates is observed for velocities above 15.3 m s{sup 1}. A comparison of the experimentally derived sticking threshold with model predictions is performed to determine important material properties of water ice, i.e., the specific surface energy and the viscous relaxation time. Our experimental results indicate that the presence of water ice in the outer reaches of protoplanetary disks can enhance the growth of planetesimals by direct sticking of particles.

  13. THE STRUCTURE OF SURFACE H{sub 2}O LAYERS OF ICE-COVERED PLANETS WITH HIGH-PRESSURE ICE

    SciTech Connect (OSTI)

    Ueta, S.; Sasaki, T. E-mail: takanori@geo.titech.ac.jp

    2013-10-01

    Many extrasolar (bound) terrestrial planets and free-floating (unbound) planets have been discovered. While the existence of bound and unbound terrestrial planets with liquid water is an important question, of particular importance is the question of these planets' habitability. Even for a globally ice-covered planet, geothermal heat from the planetary interior may melt the interior ice, creating an internal ocean covered by an ice shell. In this paper, we discuss the conditions that terrestrial planets must satisfy for such an internal ocean to exist on the timescale of planetary evolution. The question is addressed in terms of planetary mass, distance from a central star, water abundance, and abundance of radiogenic heat sources. In addition, we investigate the structure of the surface H{sub 2}O layers of ice-covered planets by considering the effects of ice under high pressure (high-pressure ice). As a fiducial case, a 1 M{sub ?} planet at 1 AU from its central star and with 0.6-25 times the H{sub 2}O mass of the Earth could have an internal ocean. We find that high-pressure ice layers may appear between the internal ocean and the rock portion on a planet with an H{sub 2}O mass over 25 times that of the Earth. The planetary mass and abundance of surface water strongly restrict the conditions under which an extrasolar terrestrial planet may have an internal ocean with no high-pressure ice under the ocean. Such high-pressure ice layers underlying the internal ocean are likely to affect the habitability of the planet.

  14. Global Simulations of Ice nucleation and Ice Supersaturation with an

    Office of Scientific and Technical Information (OSTI)

    Improved Cloud Scheme in the Community Atmosphere Model (Journal Article) | SciTech Connect Global Simulations of Ice nucleation and Ice Supersaturation with an Improved Cloud Scheme in the Community Atmosphere Model Citation Details In-Document Search Title: Global Simulations of Ice nucleation and Ice Supersaturation with an Improved Cloud Scheme in the Community Atmosphere Model A process-based treatment of ice supersaturation and ice-nucleation is implemented in the National Center for

  15. Global Simulations of Ice nucleation and Ice Supersaturation...

    Office of Scientific and Technical Information (OSTI)

    Global Simulations of Ice nucleation and Ice Supersaturation with an Improved Cloud ... Country of Publication: United States Language: English Subject: 54 ENVIRONMENTAL SCIENCES; ...

  16. Community Ice Sheet Model (CISM2) Development and Marine Ice...

    Office of Scientific and Technical Information (OSTI)

    Community Ice Sheet Model (CISM2) Development and Marine Ice Sheet Simulations Citation ... Sponsoring Org: DOELANL Country of Publication: United States Language: English Subject: ...

  17. OBSERVATIONAL CONSTRAINTS ON METHANOL PRODUCTION IN INTERSTELLAR AND PREPLANETARY ICES

    SciTech Connect (OSTI)

    Whittet, D. C. B.; Cook, A. M.; Herbst, Eric; Chiar, J. E.; Shenoy, S. S.

    2011-11-20

    Methanol (CH{sub 3}OH) is thought to be an important link in the chain of chemical evolution that leads from simple diatomic interstellar molecules to complex organic species in protoplanetary disks that may be delivered to the surfaces of Earthlike planets. Previous research has shown that CH{sub 3}OH forms in the interstellar medium predominantly on the surfaces of dust grains. To enhance our understanding of the conditions that lead to its efficient production, we assemble a homogenized catalog of published detections and limiting values in interstellar and preplanetary ices for both CH{sub 3}OH and the other commonly observed C- and O-bearing species, H{sub 2}O, CO, and CO{sub 2}. We use this catalog to investigate the abundance of ice-phase CH{sub 3}OH in environments ranging from dense molecular clouds to circumstellar envelopes around newly born stars of low and high mass. Results show that CH{sub 3}OH production arises during the CO freezeout phase of ice-mantle growth in the clouds, after an ice layer rich in H{sub 2}O and CO{sub 2} is already in place on the dust, in agreement with current astrochemical models. The abundance of solid-phase CH{sub 3}OH in this environment is sufficient to account for observed gas-phase abundances when the ices are subsequently desorbed in the vicinity of embedded stars. CH{sub 3}OH concentrations in the ices toward embedded stars show order-of-magnitude object-to-object variations, even in a sample restricted to stars of low mass associated with ices lacking evidence of thermal processing. We hypothesize that the efficiency of CH{sub 3}OH production in dense cores and protostellar envelopes is mediated by the degree of prior CO depletion.

  18. Ice - an explicit wavelet calculation code for ICE experiments.

    Office of Scientific and Technical Information (OSTI)

    (Conference) | SciTech Connect Ice - an explicit wavelet calculation code for ICE experiments. Citation Details In-Document Search Title: Ice - an explicit wavelet calculation code for ICE experiments. No abstract prepared. Authors: Furnish, Michael David Publication Date: 2004-06-01 OSTI Identifier: 953323 Report Number(s): SAND2004-2878C TRN: US200915%%27 DOE Contract Number: AC04-94AL85000 Resource Type: Conference Resource Relation: Conference: Proposed for presentation at the ICE

  19. Arctic Sea ice model sensitivities.

    SciTech Connect (OSTI)

    Peterson, Kara J.; Bochev, Pavel Blagoveston; Paskaleva, Biliana Stefanova

    2010-12-01

    Arctic sea ice is an important component of the global climate system and, due to feedback effects, the Arctic ice cover is changing rapidly. Predictive mathematical models are of paramount importance for accurate estimates of the future ice trajectory. However, the sea ice components of Global Climate Models (GCMs) vary significantly in their prediction of the future state of Arctic sea ice and have generally underestimated the rate of decline in minimum sea ice extent seen over the past thirty years. One of the contributing factors to this variability is the sensitivity of the sea ice state to internal model parameters. A new sea ice model that holds some promise for improving sea ice predictions incorporates an anisotropic elastic-decohesive rheology and dynamics solved using the material-point method (MPM), which combines Lagrangian particles for advection with a background grid for gradient computations. We evaluate the variability of this MPM sea ice code and compare it with the Los Alamos National Laboratory CICE code for a single year simulation of the Arctic basin using consistent ocean and atmospheric forcing. Sensitivities of ice volume, ice area, ice extent, root mean square (RMS) ice speed, central Arctic ice thickness,and central Arctic ice speed with respect to ten different dynamic and thermodynamic parameters are evaluated both individually and in combination using the Design Analysis Kit for Optimization and Terascale Applications (DAKOTA). We find similar responses for the two codes and some interesting seasonal variability in the strength of the parameters on the solution.

  20. ARM - Measurement - Ozone Column Abundance

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Column Abundance ARM Data Discovery Browse Data Comments? We would love to hear from you! Send us a note below or call us at 1-888-ARM-DATA. Send Measurement : Ozone Column Abundance The vertically integrated amount of ozone (commonly measured in Dobson Unit, 1 DU = 134 mmol/m^2) Categories Atmospheric State Instruments The above measurement is considered scientifically relevant for the following instruments. Refer to the datastream (netcdf) file headers of each instrument for a list of all

  1. From Fire to Ice

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Fire to Ice For original submission and image(s), see ARM Research Highlights http://www.arm.gov/science/highlights/ Research Highlight When tons of ash spewed into the atmosphere from a 2010 Icelandic volcano, it caused havoc for vacationers across Europe. But did it also dramatically change clouds? Researchers at Pacific Northwest National Laboratory (PNNL) found that volcanic ash is not as efficient as common dust in birthing clouds' ice particles. Using a novel laboratory testing chamber,

  2. Abundant Renewable Energy ARE | Open Energy Information

    Open Energy Info (EERE)

    Abundant Renewable Energy ARE Jump to: navigation, search Name: Abundant Renewable Energy (ARE) Place: Newberg, Oregon Zip: 97132 Sector: Solar, Wind energy Product: Oregon-based...

  3. A NEW SOURCE OF CO{sub 2} IN THE UNIVERSE: A PHOTOACTIVATED ELEY-RIDEAL SURFACE REACTION ON WATER ICES

    SciTech Connect (OSTI)

    Yuan, Chunqing; Cooke, Ilsa R.; Yates, John T. Jr.

    2014-08-20

    CO{sub 2} is one of the most abundant components of ices in the interstellar medium; however, its formation mechanism has not been clearly identified. Here we report an experimental observation of an Eley-Rideal-type reaction on a water ice surface, where CO gas molecules react by direct collisions with surface OH radicals, made by photodissociation of H{sub 2}O molecules, to produce CO{sub 2} ice on the surface. The discovery of this source of CO{sub 2} provides a new mechanism to explain the high relative abundance of CO{sub 2} ice in space.

  4. ARM - TWP-ICE Maps

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Fact Sheet (pdf, 211K) Press Releases TWP-ICE Images ARM flickr site <"" li"" height"14" width"16"> TWP-ICE Maps map1 map2 Download TWP-ICEDarwin annotated maps (pdf, 246K)....

  5. TWO-PHOTON PHYSICS IN NUCLEUS-NUCLEUS COLLISIONS AT RHIC.

    SciTech Connect (OSTI)

    NYSTRAND,J.

    1998-09-10

    Ultra-relativistic heavy-ions carry strong electromagnetic and nuclear fields. Interactions between these fields in peripheral nucleus-nucleus collisions can probe many interesting physics topics. This presentation will focus on coherent two-photon and photonuclear processes at RHIC. The rates for these interactions will be high. The coherent coupling of all the protons in the nucleus enhances the equivalent photon flux by a factor Z{sup 2} up to an energy of {approx} 3 GeV. The plans for studying coherent interactions with the STAR experiment will be discussed. Experimental techniques for separating signal from background will be presented.

  6. Ice Storm Supercomputer

    ScienceCinema (OSTI)

    None

    2013-05-28

    "A new Idaho National Laboratory supercomputer is helping scientists create more realistic simulations of nuclear fuel. Dubbed 'Ice Storm,' this 2048-processor machine allows researchers to model and predict the complex physics behind nuclear reactor behavior. And with a new visualization lab, the team can see the results of its simulations on the big screen." For more information about INL research, visit http://www.facebook.com/idahonationallaboratory.

  7. ARM - Measurement - Cloud ice particle

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    ice particle ARM Data Discovery Browse Data Comments? We would love to hear from you! Send us a note below or call us at 1-888-ARM-DATA. Send Measurement : Cloud ice particle Particles made of ice found in clouds. Categories Cloud Properties Instruments The above measurement is considered scientifically relevant for the following instruments. Refer to the datastream (netcdf) file headers of each instrument for a list of all available measurements, including those recorded for diagnostic or

  8. Winter Preparedness ? Slips on Ice

    Broader source: Energy.gov (indexed) [DOE]

    can further increase traction; however, they must be removed when ice is no longer present, because their use on floors, smooth concrete, or gravel, presents a different...

  9. Climate Impacts of Ice Nucleation

    SciTech Connect (OSTI)

    Gettelman, A.; Liu, Xiaohong; Barahona, Donifan; Lohmann, U.; Chen, Chih-Chieh

    2012-10-27

    Several different ice nucleation parameterizations in two different General Circulation Models are used to understand the effects of ice nucleation on the mean climate state, and the climate effect of aerosol perturbations to ice clouds. The simulations have different ice microphysical states that are consistent with the spread of observations. These different states occur from different parameterizations of the ice cloud nucleation processes, and feature different balances of homogeneous and heterogeneous nucleation. At reasonable efficiencies, consistent with laboratory measurements and constrained by the global radiative balance, black carbon has a small (-0.06 Wm?2) and not statistically significant climate effect. Indirect effects of anthropogenic aerosols on cirrus clouds occur mostly due to increases in homogeneous nucleation fraction as a consequence of anthropogenic sulfur emissions. The resulting ice indirect effects do not seem strongly dependent on the ice micro-physical balance, but are slightly larger for those states with less homogeneous nucleation in the base state. The total ice AIE is estimated at 0.260.09 Wm?2 (1? uncertainty). This represents an offset of 20-30% of the simulated total Aerosol Indirect Effect for ice and liquid clouds.

  10. Therapeutic Hypothermia: Protective Cooling Using Medical Ice...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Therapeutic Hypothermia: Protective Cooling Using Medical Ice Slurry Technology available for licensing: Proprietary method and equipment for making an ice slurry coolant to induce...

  11. Biogeochemistry in Sea Ice: CICE model developments

    SciTech Connect (OSTI)

    Jeffery, Nicole; Hunke, Elizabeth; Elliott, Scott; Turner, Adrian

    2012-06-18

    Polar primary production unfolds in a dynamic sea ice environment, and the interactions of sea ice with ocean support and mediate this production. In spring, for example, fresh melt water contributes to the shoaling of the mixed layer enhancing ice edge blooms. In contrast, sea ice formation in the fall reduces light penetration to the upper ocean slowing primary production in marine waters. Polar biogeochemical modeling studies typically consider these types of ice-ocean interactions. However, sea ice itself is a biogeochemically active medium, contributing a significant and, possibly, essential source of primary production to polar regions in early spring and fall. Here we present numerical simulations using the Los Alamos Sea Ice Model (CICE) with prognostic salinity and sea ice biogeochemistry. This study investigates the relationship between sea ice multiphase physics and sea ice productivity. Of particular emphasis are the processes of gravity drainage, melt water flushing, and snow loading. During sea ice formation, desalination by gravity drainage facilitates nutrient exchange between ocean and ice maintaining ice algal blooms in early spring. Melt water flushing releases ice algae and nutrients to underlying waters limiting ice production. Finally, snow loading, particularly in the Southern Ocean, forces sea ice below the ocean surface driving an upward flow of nutrient rich water into the ice to the benefit of interior and freeboard communities. Incorporating ice microphysics in CICE has given us an important tool for assessing the importance of these processes for polar algal production at global scales.

  12. Light propagation in the South Pole ice

    SciTech Connect (OSTI)

    Williams, Dawn; Collaboration: IceCube Collaboration

    2014-11-18

    The IceCube Neutrino Observatory is located in the ice near the geographic South Pole. Particle showers from neutrino interactions in the ice produce light which is detected by IceCube modules, and the amount and pattern of deposited light are used to reconstruct the properties of the incident neutrino. Since light is scattered and absorbed by ice between the neutrino interaction vertex and the sensor, IceCube event reconstruction depends on understanding the propagation of light through the ice. This paper presents the current status of modeling light propagation in South Pole ice, including the recent observation of an azimuthal anisotropy in the scattering.

  13. Earth-abundant semiconductors for photovoltaic applications ...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Earth-abundant semiconductors for photovoltaic applications Thin film photovoltaics (solar cells) has the potential to revolutionize our energy landscape by producing clean,...

  14. The New ICE Age | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    The New ICE Age The New ICE Age Provides overview of internal combustion engine powertrain developments for the heavy truck market PDF icon deer12_gruden.pdf More Documents & Publications The New ICE Age The New ICE Age Roadmapping Engine Technology for Post-2020 Heavy Duty Vehicles

  15. Method of forming calthrate ice

    DOE Patents [OSTI]

    Hino, T.; Gorski, A.J.

    1985-09-30

    A method of forming clathrate ice in a supercooled water-based liquid contained in a vessel is disclosed. Initially, an oscillator device is located in the liquid in the vessel. The oscillator device is then oscillated ultransonically so that small crystals are formed in the liquid. Thes small crystals serve as seed crystals for ice formation in the liquid and thereby prevent supercooling of the liquid. Preferably, the oscillating device is controlled by a thermostat which initiates operation of the oscillator device when the temperature of the liquid is lowered to the freezing point. Thereafter, the operation of the oscillator device is terminated when ice is sensed in the liquid by an ice sensor.

  16. Method of forming clathrate ice

    DOE Patents [OSTI]

    Hino, Toshiyuki (Tokyo, JP); Gorski, Anthony J. (Lemont, IL)

    1987-01-01

    A method of forming clathrate ice in a supercooled water-based liquid contained in a vessel is disclosed. Initially, an oscillator device is located in the liquid in the vessel. The oscillator device is then oscillated ultrasonically so that small crystals are formed in the liquid. These small crystals serve as seed crystals for ice formation in the liquid and thereby prevent supercooling of the liquid. Preferably, the oscillating device is controlled by a thermostat which initiates operation of the oscillator device when the temperature of the liquid is lowered to the freezing point. Thereafter, the operation of the oscillator device is terminated when ice is sensed in the liquid by an ice sensor.

  17. BISICLES Captures Details of Retreating Antarctic Ice

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    BISICLES Captures Details of Retreating Antarctic Ice BISICLES Captures Details of Retreating Antarctic Ice March 30, 2013 Contact: Linda Vu, lvu@lbl.gov, +1 510 495 2402 Satellite observations suggest that the shrinking West Antarctic ice sheet is contributing to global sea level rise. But until recently, scientists could not accurately model the physical processes driving retreat of the ice sheet. Now, a new ice sheet model-called Berkeley-ISICLES (BISICLES)-is shedding light on these details.

  18. ARM - Measurement - Ice water content

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    content ARM Data Discovery Browse Data Comments? We would love to hear from you! Send us a note below or call us at 1-888-ARM-DATA. Send Measurement : Ice water content The concentration (mass/vol) of ice water particles in a cloud. Categories Atmospheric State, Cloud Properties Instruments The above measurement is considered scientifically relevant for the following instruments. Refer to the datastream (netcdf) file headers of each instrument for a list of all available measurements, including

  19. Highway De-icing Snowmelt Low Temperature Geothermal Facility...

    Open Energy Info (EERE)

    De-icing Snowmelt Low Temperature Geothermal Facility Jump to: navigation, search Name Highway De-icing Snowmelt Low Temperature Geothermal Facility Facility Highway De-icing...

  20. Earth-Abundant Materials | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Photovoltaics » Earth-Abundant Materials Earth-Abundant Materials Graphic showing the five layers of a CZTS PV cell: Mo-coated substrate, CZTS light absorber, n- CdS, i-ZnO, and transparent conductive oxide. DOE funds research into Earth-abundant materials for thin-film solar applications in response to the issue of materials scarcity surrounding other photovoltaic (PV) technologies. The sections below contain a list of the projects, summary of the benefits, and discussion on the production and

  1. Vapor deposition of water on graphitic surfaces: Formation of amorphous ice, bilayer ice, ice I, and liquid water

    SciTech Connect (OSTI)

    Lupi, Laura; Kastelowitz, Noah; Molinero, Valeria

    2014-11-14

    Carbonaceous surfaces are a major source of atmospheric particles and could play an important role in the formation of ice. Here we investigate through molecular simulations the stability, metastability, and molecular pathways of deposition of amorphous ice, bilayer ice, and ice I from water vapor on graphitic and atomless Lennard-Jones surfaces as a function of temperature. We find that bilayer ice is the most stable ice polymorph for small cluster sizes, nevertheless it can grow metastable well above its region of thermodynamic stability. In agreement with experiments, the simulations predict that on increasing temperature the outcome of water deposition is amorphous ice, bilayer ice, ice I, and liquid water. The deposition nucleation of bilayer ice and ice I is preceded by the formation of small liquid clusters, which have two wetting states: bilayer pancake-like (wetting) at small cluster size and droplet-like (non-wetting) at larger cluster size. The wetting state of liquid clusters determines which ice polymorph is nucleated: bilayer ice nucleates from wetting bilayer liquid clusters and ice I from non-wetting liquid clusters. The maximum temperature for nucleation of bilayer ice on flat surfaces, T{sub B}{sup max} is given by the maximum temperature for which liquid water clusters reach the equilibrium melting line of bilayer ice as wetting bilayer clusters. Increasing water-surface attraction stabilizes the pancake-like wetting state of liquid clusters leading to larger T{sub B}{sup max} for the flat non-hydrogen bonding surfaces of this study. The findings of this study should be of relevance for the understanding of ice formation by deposition mode on carbonaceous atmospheric particles, including soot.

  2. Determination of electron-nucleus collisions geometry with forward neutrons

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Zheng, L.; Aschenauer, E.; Lee, J. H.

    2014-12-29

    There are a large number of physics programs one can explore in electron-nucleus collisions at a future electron-ion collider. Collision geometry is very important in these studies, while the measurement for an event-by-event geometric control is rarely discussed in the prior deep-inelastic scattering experiments off a nucleus. This paper seeks to provide some detailed studies on the potential of tagging collision geometries through forward neutron multiplicity measurements with a zero degree calorimeter. As a result, this type of geometry handle, if achieved, can be extremely beneficial in constraining nuclear effects for the electron-nucleus program at an electron-ion collider.

  3. Quarkonium-nucleus bound states from lattice QCD

    SciTech Connect (OSTI)

    Beane, S.  R.; Chang, E.; Cohen, S.  D.; Detmold, W.; Lin, H. -W.; Orginos, K.; Parreño, A.; Savage, M.  J.

    2015-06-11

    Quarkonium-nucleus systems are composed of two interacting hadronic states without common valence quarks, which interact primarily through multi-gluon exchanges, realizing a color van der Waals force. We present lattice QCD calculations of the interactions of strange and charm quarkonia with light nuclei. Both the strangeonium-nucleus and charmonium-nucleus systems are found to be relatively deeply bound when the masses of the three light quarks are set equal to that of the physical strange quark. Extrapolation of these results to the physical light-quark masses suggests that the binding energy of charmonium to nuclear matter is B < 40 MeV.

  4. The measured compositions of Uranus and Neptune from their formation on the CO ice line

    SciTech Connect (OSTI)

    Ali-Dib, Mohamad; Mousis, Olivier; Petit, Jean-Marc

    2014-09-20

    The formation mechanisms of the ice giants Uranus and Neptune, and the origin of their elemental and isotopic compositions, have long been debated. The density of solids in the outer protosolar nebula is too low to explain their formation, and spectroscopic observations show that both planets are highly enriched in carbon, very poor in nitrogen, and the ices from which they originally formed might have had deuterium-to-hydrogen ratios lower than the predicted cometary value, unexplained properties that were observed in no other planets. Here, we show that all these properties can be explained naturally if Uranus and Neptune both formed at the carbon monoxide ice line. Due to the diffusive redistribution of vapors, this outer region of the protosolar nebula intrinsically has enough surface density to form both planets from carbon-rich solids but nitrogen-depleted gas, in abundances consistent with their observed values. Water-rich interiors originating mostly from transformed CO ices reconcile the D/H value of Uranus's and Neptune's building blocks with the cometary value. Finally, our scenario generalizes a well known hypothesis that Jupiter formed on an ice line (water snow line) for the two ice giants, and might be a first step toward generalizing this mechanism for other giant planets.

  5. ARM - Measurement - Ice water path

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    path ARM Data Discovery Browse Data Comments? We would love to hear from you! Send us a note below or call us at 1-888-ARM-DATA. Send Measurement : Ice water path A measure of the weight of the ice particles in the atmosphere above a unit surface area in kg m-2. Categories Cloud Properties Instruments The above measurement is considered scientifically relevant for the following instruments. Refer to the datastream (netcdf) file headers of each instrument for a list of all available measurements,

  6. Ice in Arctic Mixed-phase Stratocumulus

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Ice Nuclei Recycling in the Maintenance of Cloud Ice in Arctic Mixed-phase Stratocumulus For original submission and image(s), see ARM Research Highlights http:www.arm.gov...

  7. Contractor SOW Template - ICE | Department of Energy

    Energy Savers [EERE]

    ICE Contractor SOW Template - ICE The template presented below is a Statement of Work (SOW) for services of an ICE Support Contractor for assisting OECM in conducting an ICE. Project and review specific information should be incorporated. Explanatory text appears in italics, while information that should be selected appears in <<brackets>>. The format and contents of this SOW is not compulsory, and the use is at the discretion of the OECM Analysts, tailored as appropriate for the

  8. Abundances for p-process nucleosynthesis

    SciTech Connect (OSTI)

    De Laeter, John R.

    2008-04-15

    An important constraint in developing models of p-process nucleosynthesis is that the abundances of many of the p-process nuclides are not well known. A recent review of the p-process has identified six p-process nuclides that are of particular significance to p-process theorists [M. Arnould and S. Goriely, Phys. Rep. 384, 1 (2003)]. These nuclides are {sup 92,94}Mo, {sup 96,98}Ru, {sup 138}La, and {sup 180}Ta{sup m}. The absence of accurate abundances for these isotopes is due to the fact that the isotopic composition of the elements concerned have not been corrected for isotope fractionation induced by the thermal ionization mass spectrometric instruments used to measure them. To remedy this deficiency, a VG 354 mass spectrometer was calibrated using gravimetric mixtures of enriched isotopes to enable the absolute isotopic compositions of these elements to be obtained. Although the isotopic abundances of {sup 92,94}Mo, {sup 138}La, and {sup 180}Ta{sup m} have previously been reported, the absolute abundances of {sup 96,98}Ru are reported for the first time in this article, with a significant reduction in the magnitude of the values as compared to existing abundances.

  9. Medical ice slurry production device

    DOE Patents [OSTI]

    Kasza, Kenneth E.; Oras, John; Son, HyunJin

    2008-06-24

    The present invention relates to an apparatus for producing sterile ice slurries for medical cooling applications. The apparatus is capable of producing highly loaded slurries suitable for delivery to targeted internal organs of a patient, such as the brain, heart, lungs, stomach, kidneys, pancreas, and others, through medical size diameter tubing. The ice slurry production apparatus includes a slurry production reservoir adapted to contain a volume of a saline solution. A flexible membrane crystallization surface is provided within the slurry production reservoir. The crystallization surface is chilled to a temperature below a freezing point of the saline solution within the reservoir such that ice particles form on the crystallization surface. A deflector in the form of a reciprocating member is provided for periodically distorting the crystallization surface and dislodging the ice particles which form on the crystallization surface. Using reservoir mixing the slurry is conditioned for easy pumping directly out of the production reservoir via medical tubing or delivery through other means such as squeeze bottles, squeeze bags, hypodermic syringes, manual hand delivery, and the like.

  10. Nucleus-nucleus cold fusion reactions analyzed with the l-dependent 'fusion by diffusion' model

    SciTech Connect (OSTI)

    Cap, T.; Siwek-Wilczynska, K.; Wilczynski, J.

    2011-05-15

    We present a modified version of the Fusion by Diffusion (FBD) model aimed at describing the synthesis of superheavy nuclei in cold fusion reactions, in which a low excited compound nucleus emits only one neutron. The modified FBD model accounts for the angular momentum dependence of three basic factors determining the evaporation residue cross section: the capture cross section {sigma}{sub cap}(l), the fusion probability P{sub fus}(l), and the survival probability P{sub surv}(l). The fusion hindrance factor, the inverse of P{sub fus}(l), is treated in terms of thermal fluctuations in the shape degrees of freedom and is expressed as a solution of the Smoluchowski diffusion equation. The l dependence of P{sub fus}(l) results from the l-dependent potential energy surface of the colliding system. A new parametrization of the distance of starting point of the diffusion process is introduced. An analysis of a complete set of 27 excitation functions for production of superheavy nuclei in cold fusion reactions, studied in experiments at GSI Darmstadt, RIKEN Tokyo, and LBNL Berkeley, is presented. The FBD model satisfactorily reproduces shapes and absolute cross sections of all the cold fusion excitation functions. It is shown that the peak position of the excitation function for a given 1n reaction is determined by the Q value of the reaction and the height of the fission barrier of the final nucleus. This fact could possibly be used in future experiments (with well-defined beam energy) for experimental determination of the fission barrier heights.

  11. The Dependence of Subhalo Abundance on Halo Concentration (Journal...

    Office of Scientific and Technical Information (OSTI)

    The Dependence of Subhalo Abundance on Halo Concentration Citation Details In-Document Search Title: The Dependence of Subhalo Abundance on Halo Concentration Authors: Mao,...

  12. Isotopic abundance in atom trap trace analysis

    DOE Patents [OSTI]

    Lu, Zheng-Tian; Hu, Shiu-Ming; Jiang, Wei; Mueller, Peter

    2014-03-18

    A method and system for detecting ratios and amounts of isotopes of noble gases. The method and system is constructed to be able to measure noble gas isotopes in water and ice, which helps reveal the geological age of the samples and understand their movements. The method and system uses a combination of a cooled discharge source, a beam collimator, a beam slower and magneto-optic trap with a laser to apply resonance frequency energy to the noble gas to be quenched and detected.

  13. Energy Cost Calculator for Commercial Ice Machines | Department of Energy

    Office of Environmental Management (EM)

    Ice Machines Energy Cost Calculator for Commercial Ice Machines Vary capacity size, energy cost, hours of operation, and /or efficiency level. INPUT SECTION Input the following data (if any parameter is missing, calculator will set to default value). Defaults Type of Ice Cube Machine Ice Making Head Self-Contained Remote Condensing Unit Ice Making Head Type of Condenser Air Cooled Water Cooled Air Cooled Ice Harvest Rate (lbs. ice per 24 hrs.) lbs. per 24 hrs. 500 lbs. per 24 hrs. Energy

  14. Hydrogen ICE Vehicle Testing Activities

    SciTech Connect (OSTI)

    J. Francfort; D. Karner

    2006-04-01

    The Advanced Vehicle Testing Activity teamed with Electric Transportation Applications and Arizona Public Service to develop and monitor the operations of the APS Alternative Fuel (Hydrogen) Pilot Plant. The Pilot Plant provides 100% hydrogen, and hydrogen and compressed natural gas (H/CNG)-blended fuels for the evaluation of hydrogen and H/CNG internal combustion engine (ICE) vehicles in controlled and fleet testing environments. Since June 2002, twenty hydrogen and H/CNG vehicles have accumulated 300,000 test miles and 5,700 fueling events. The AVTA is part of the Department of Energy’s FreedomCAR and Vehicle Technologies Program. These testing activities are managed by the Idaho National Laboratory. This paper discusses the Pilot Plant design and monitoring, and hydrogen ICE vehicle testing methods and results.

  15. ORTHO-TO-PARA ABUNDANCE RATIO OF WATER ION IN COMET C/2001 Q4 (NEAT): IMPLICATION FOR ORTHO-TO-PARA ABUNDANCE RATIO OF WATER

    SciTech Connect (OSTI)

    Shinnaka, Yoshiharu; Kawakita, Hideyo; Kobayashi, Hitomi; Boice, Daniel C.; Martinez, Susan E.

    2012-04-20

    The ortho-to-para abundance ratio (OPR) of cometary molecules is considered to be one of the primordial characteristics of cometary ices, and contains information concerning their formation. Water is the most abundant species in cometary ices, and OPRs of water in comets have been determined from infrared spectroscopic observations of H{sub 2}O rovibrational transitions so far. In this paper, we present a new method to derive OPR of water in comets from the high-dispersion spectrum of the rovibronic emission of H{sub 2}O{sup +} in the optical wavelength region. The rovibronic emission lines of H{sub 2}O{sup +} are sometimes contaminated by other molecular emission lines but they are not affected seriously by telluric absorption compared with near-infrared observations. Since H{sub 2}O{sup +} ions are mainly produced from H{sub 2}O by photoionization in the coma, the OPR of H{sub 2}O{sup +} is considered to be equal to that of water based on the nuclear spin conservation through the reaction. We have developed a fluorescence excitation model of H{sub 2}O{sup +} and applied it to the spectrum of comet C/2001 Q4 (NEAT). The derived OPR of water is 2.54{sup +0.32}{sub -0.25}, which corresponds to a nuclear spin temperature (T{sub spin}) of 30{sup +10}{sub -4} K. This is consistent with the previous value determined in the near-infrared for the same comet (OPR = 2.6 {+-} 0.3, T{sub spin} = 31{sup +11}{sub -5} K).

  16. INDEPENDENT COST REVIEW (ICR) and INDEPENDENT COST ESTIMATE (ICE) Standard

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Operating Procedures | Department of Energy INDEPENDENT COST REVIEW (ICR) and INDEPENDENT COST ESTIMATE (ICE) Standard Operating Procedures INDEPENDENT COST REVIEW (ICR) and INDEPENDENT COST ESTIMATE (ICE) Standard Operating Procedures PDF icon ICR_ICE SOP_Sep 2013_Final.pdf More Documents & Publications ICR-ICE Standard Operating Procedures (Update Sept 2013) Contractor SOW Template - ICR Contractor SOW Template - ICE

  17. Automatic Commercial Ice Makers | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Automatic Commercial Ice Makers Automatic Commercial Ice Makers The Department of Energy (DOE) develops standardized data templates for reporting the results of tests conducted in accordance with current DOE test procedures. Templates may be used by third-party laboratories under contract with DOE that conduct testing in support of ENERGY STAR® verification, DOE rulemakings, and enforcement of the federal energy conservation standards. File Automatic Commercial Ice Makers -- v2.0 More Documents

  18. ARM - Lesson Plans: When Land Ice Melts

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    When Land Ice Melts Outreach Home Room News Publications Traditional Knowledge Kiosks Barrow, Alaska Tropical Western Pacific Site Tours Contacts Students Study Hall About ARM Global Warming FAQ Just for Fun Meet our Friends Cool Sites Teachers Teachers' Toolbox Lesson Plans Lesson Plans: When Land Ice Melts Objective The objective of this activity is to demonstrate what happens when land ice melts and how it is different from the effect of melting icebergs. Materials A big rectangular container

  19. Community Ice Sheet Model (CISM2) Development and Marine Ice Sheet

    Office of Scientific and Technical Information (OSTI)

    Simulations (Conference) | SciTech Connect Community Ice Sheet Model (CISM2) Development and Marine Ice Sheet Simulations Citation Details In-Document Search Title: Community Ice Sheet Model (CISM2) Development and Marine Ice Sheet Simulations Authors: Lipscomb, William [1] ; Leguy, Gunter [1] + Show Author Affiliations Los Alamos National Laboratory Publication Date: 2015-06-17 OSTI Identifier: 1186039 Report Number(s): LA-UR-15-24514 DOE Contract Number: AC52-06NA25396 Resource Type:

  20. Viscosity of interfacial water regulates ice nucleation

    SciTech Connect (OSTI)

    Li, Kaiyong; Chen, Jing; Zhang, Qiaolan; Zhang, Yifan; University of Chinese Academy of Sciences, Beijing 100049 ; Xu, Shun; Zhou, Xin; Cui, Dapeng; Wang, Jianjun Song, Yanlin

    2014-03-10

    Ice formation on solid surfaces is an important phenomenon in many fields, such as cloud formation and atmospheric icing, and a key factor for applications in preventing freezing. Here, we report temperature-dependent nucleation rates of ice for hydrophilic and hydrophobic surfaces. The results show that hydrophilic surface presents a lower ice nucleation rate. We develop a strategy to extract the thermodynamic parameters, J{sub 0} and ?, in the context of classical nucleation theory. From the extracted J{sub 0} and ?, we reveal the dominant role played by interfacial water. The results provide an insight into freezing mechanism on solid surfaces.

  1. BISICLES Captures Details of Retreating Antarctic Ice

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    ... Satellite and ground observations show that the ice in this region is thinning and retreating significantly as shifting wind patterns and ocean currents allow warmer water to flow ...

  2. Comparison of 17 Ice Nucleation Measurement Techniques

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    17 Ice Nucleation Measurement Techniques for Immersion Freezing For original submission and image(s), see ARM Research Highlights http:www.arm.govsciencehighlights Research...

  3. Reprocessing of ices in turbulent protoplanetary disks: Carbon and nitrogen chemistry

    SciTech Connect (OSTI)

    Furuya, Kenji; Aikawa, Yuri

    2014-08-01

    We study the influence of the turbulent transport on ice chemistry in protoplanetary disks, focusing on carbon- and nitrogen-bearing molecules. Chemical rate equations are solved with the diffusion term, mimicking the turbulent mixing in the vertical direction. Turbulence can bring ice-coated dust grains from the midplane to the warm irradiated disk surface, and the ice mantles are reprocessed by photoreactions, thermal desorption, and surface reactions. The upward transport decreases the abundance of methanol and ammonia ices at r ? 30 AU because warm dust temperature prohibits their reformation on grain surfaces. This reprocessing could explain the smaller abundances of carbon and nitrogen bearing molecules in cometary coma than those in low-mass protostellar envelopes. We also show the effect of mixing on the synthesis of complex organic molecules (COMs) in two ways: (1) transport of ices from the midplane to the disk surface and (2) transport of atomic hydrogen from the surface to the midplane. The former enhances the COMs formation in the disk surface, while the latter suppresses it in the midplane. Then, when mixing is strong, COMs are predominantly formed in the disk surface, while their parent molecules are (re)formed in the midplane. This cycle expands the COMs distribution both vertically and radially outward compared with that in the non-turbulent model. We derive the timescale of the sink mechanism by which CO and N{sub 2} are converted to less volatile molecules to be depleted from the gas phase and find that the vertical mixing suppresses this mechanism in the inner disks.

  4. Ice Nuclei in Marine Air: Biogenic Particles or Dust?

    SciTech Connect (OSTI)

    Burrows, Susannah M.; Hoose, C.; Poschl, U.; Lawrence, M.

    2013-01-11

    Ice nuclei impact clouds, but their sources and distribution in the atmosphere are still not well known. Particularly little attention has been paid to IN sources in marine environments, although evidence from field studies suggests that IN populations in remote marine regions may be dominated by primary biogenic particles associated with sea spray. In this exploratory model study, we aim to bring attention to this long-neglected topic and identify promising target regions for future field campaigns. We assess the likely global distribution of marine biogenic ice nuclei using a combination of historical observations, satellite data and model output. By comparing simulated marine biogenic immersion IN distributions and dust immersion IN distributions, we predict strong regional differences in the importance of marine biogenic IN relative to dust IN. Our analysis suggests that marine biogenic IN are most likely to play a dominant role in determining IN concentrations in near-surface-air over the Southern Ocean, so future field campaigns aimed at investigating marine biogenic IN should target that region. Climate related changes in the abundance and emission of biogenic marine IN could affect marine cloud properties, thereby introducing previously unconsidered feedbacks that influence the hydrological cycle and the Earths energy balance. Furthermore, marine biogenic IN may be an important aspect to consider in proposals for marine cloud brightening by artificial sea spray production.

  5. fire-in-the-ice | netl.doe.gov

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Fire in the Ice The methane hydrate newsletter, Fire in the Ice, is a quarterly publication highlighting the latest developments in international gas hydrates R&D. Fire in the Ice...

  6. Primordial Li abundance and massive particles

    SciTech Connect (OSTI)

    Latin-Capital-Letter-Eth apo, H.

    2012-10-20

    The problem of the observed lithium abundance coming from the Big Bang Nucleosynthesis is as of yet unsolved. One of the proposed solutions is including relic massive particles into the Big Bang Nucleosynthesis. We investigated the effects of such particles on {sup 4}HeX{sup -}+{sup 2}H{yields}{sup 6}Li+X{sup -}, where the X{sup -} is the negatively charged massive particle. We demonstrate the dominance of long-range part of the potential on the cross-section.

  7. ARM - PI Product - Large Scale Ice Water Path and 3-D Ice Water Content

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    ProductsLarge Scale Ice Water Path and 3-D Ice Water Content ARM Data Discovery Browse Data Comments? We would love to hear from you! Send us a note below or call us at 1-888-ARM-DATA. Send PI Product : Large Scale Ice Water Path and 3-D Ice Water Content Cloud ice water concentration is one of the most important, yet poorly observed, cloud properties. Developing physical parameterizations used in general circulation models through single-column modeling is one of the key foci of the ARM

  8. A direct evidence of vibrationally delocalized response at ice surface

    SciTech Connect (OSTI)

    Ishiyama, Tatsuya; Morita, Akihiro

    2014-11-14

    Surface-specific vibrational spectroscopic responses at isotope diluted ice and amorphous ice are investigated by molecular dynamics (MD) simulations combined with quantum mechanics/molecular mechanics calculations. The intense response specific to the ordinary crystal ice surface is predicted to be significantly suppressed in the isotopically diluted and amorphous ices, demonstrating the vibrational delocalization at the ordinary ice surface. The collective vibration at the ice surface is also analyzed with varying temperature by the MD simulation.

  9. MEASUREMENTS OF ABSOLUTE ABUNDANCES IN SOLAR FLARES

    SciTech Connect (OSTI)

    Warren, Harry P. [Space Science Division, Naval Research Laboratory, Washington, DC 20375 (United States)

    2014-05-01

    We present measurements of elemental abundances in solar flares with the EUV Variability Experiment (EVE) on the Solar Dynamics Observatory. EVE observes both high temperature Fe emission lines (Fe XV-Fe XXIV) and continuum emission from thermal bremsstrahlung that is proportional to the abundance of H. By comparing the relative intensities of line and continuum emission it is possible to determine the enrichment of the flare plasma relative to the composition of the photosphere. This is the first ionization potential or FIP bias (f). Since thermal bremsstrahlung at EUV wavelengths is relatively insensitive to the electron temperature, it is important to account for the distribution of electron temperatures in the emitting plasma. We accomplish this by using the observed spectra to infer the differential emission measure distribution and FIP bias simultaneously. In each of the 21 flares that we analyze we find that the observed composition is close to photospheric. The mean FIP bias in our sample is f = 1.17 0.22. This analysis suggests that the bulk of the plasma evaporated during a flare comes from deep in the chromosphere, below the region where elemental fractionation occurs.

  10. Passive ice freezing-releasing heat pipe

    DOE Patents [OSTI]

    Gorski, Anthony J. (Lemont, IL); Schertz, William W. (Batavia, IL)

    1982-01-01

    A heat pipe device has been developed which permits completely passive ice formation and periodic release of ice without requiring the ambient temperature to rise above the melting point of water. This passive design enables the maximum amount of cooling capacity to be stored in the tank.

  11. Department of Energy Land Ice Modeling Efforts (Conference) ...

    Office of Scientific and Technical Information (OSTI)

    Energy Land Ice Modeling Efforts Citation Details In-Document Search Title: Department of Energy Land Ice Modeling Efforts Authors: Price, Stephen F. Dr 1 + Show Author...

  12. ICR-ICE Standard Operating Procedures (Update Sept 2013) | Department...

    Broader source: Energy.gov (indexed) [DOE]

    Documents & Publications INDEPENDENT COST REVIEW (ICR) and INDEPENDENT COST ESTIMATE (ICE) Standard Operating Procedures Contractor SOW Template - ICR Contractor SOW Template - ICE...

  13. Sandia Energy - Ice-Sheet Simulation Code Matures, Leveraging...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    and as the land ice component of coupled climate simulations in DOE's Earth System Model. The land ice component is responsible for simulating the evolution of the...

  14. Complex systems influence melting of Greenland ice sheet

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    melting of Greenland ice sheet Complex systems influence melting of Greenland ice sheet International research team's field work shows that, well, things are more complicated...

  15. New climate model predicts likelihood of Greenland ice melt,...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    of accumulated carbon emissions predicts the likelihood of crossing several dangerous climate change thresholds. November 20, 2015 Greenland ice loss. Greenland ice loss....

  16. A marine biogenic source of atmospheric ice-nucleating particles...

    Office of Scientific and Technical Information (OSTI)

    A marine biogenic source of atmospheric ice-nucleating particles Citation Details In-Document Search Title: A marine biogenic source of atmospheric ice-nucleating particles The ...

  17. Greenland Ice Sheet Modeling Update (Conference) | SciTech Connect

    Office of Scientific and Technical Information (OSTI)

    Greenland Ice Sheet Modeling Update Citation Details In-Document Search Title: Greenland Ice Sheet Modeling Update You are accessing a document from the Department of Energy's...

  18. CHEMICAL PROCESSING OF PURE AMMONIA AND AMMONIA-WATER ICES INDUCED BY HEAVY IONS

    SciTech Connect (OSTI)

    Bordalo, V.; Da Silveira, E. F.; Seperuelo Duarte, E.

    2013-09-10

    Cosmic rays are possibly the main agents to prevent the freeze-out of molecules onto grain surfaces in cold dense clouds. Ammonia (NH{sub 3}) is one of the most abundant molecules present in dust ice mantles, with a concentration of up to 15% relative to water (H{sub 2}O). FTIR spectroscopy is used to monitor pure NH{sub 3} and NH{sub 3}-H{sub 2}O ice samples as they are irradiated with Ni and Zn ion beams (500-600 MeV) at GANIL/France. New species, such as hydrazine (N{sub 2}H{sub 4}), diazene (N{sub 2}H{sub 2} isomers), molecular hydrogen (H{sub 2}), and nitrogen (N{sub 2}) were identified after irradiation of pure NH{sub 3} ices. Nitrous oxide (N{sub 2}O), nitrogen oxide (NO), nitrogen dioxide (NO{sub 2}), and hydroxylamine (NH{sub 2}OH) are some of the products of the NH{sub 3}-H{sub 2}O ice radiolysis. The spectral band at 6.85 {mu}m was observed after irradiation of both types of ice. Besides the likely contribution of ammonium (NH{sub 4}{sup +}) and amino (NH{sub 2}) radicals, data suggest a small contribution of NH{sub 2}OH to this band profile after high fluences of irradiation of NH{sub 3}-H{sub 2}O ices. The spectral shift of the NH{sub 3} ''umbrella'' mode (9.3 {mu}m) band is parameterized as a function of NH{sub 3}/H{sub 2}O ratio in amorphous ices. Ammonia and water destruction cross-sections are obtained, as well as the rate of NH{sub 3}-H{sub 2}O (1:10) ice compaction, measured by the OH dangling bond destruction cross-section. Ammonia destruction is enhanced in the presence of H{sub 2}O in the ice and a power law relationship between stopping power and NH{sub 3} destruction cross-section is verified. Such results may provide relevant information for the evolution of molecular species in dense molecular clouds.

  19. Parameterizing Size Distribution in Ice Clouds

    SciTech Connect (OSTI)

    DeSlover, Daniel; Mitchell, David L.

    2009-09-25

    PARAMETERIZING SIZE DISTRIBUTIONS IN ICE CLOUDS David L. Mitchell and Daniel H. DeSlover ABSTRACT An outstanding problem that contributes considerable uncertainty to Global Climate Model (GCM) predictions of future climate is the characterization of ice particle sizes in cirrus clouds. Recent parameterizations of ice cloud effective diameter differ by a factor of three, which, for overcast conditions, often translate to changes in outgoing longwave radiation (OLR) of 55 W m-2 or more. Much of this uncertainty in cirrus particle sizes is related to the problem of ice particle shattering during in situ sampling of the ice particle size distribution (PSD). Ice particles often shatter into many smaller ice fragments upon collision with the rim of the probe inlet tube. These small ice artifacts are counted as real ice crystals, resulting in anomalously high concentrations of small ice crystals (D < 100 m) and underestimates of the mean and effective size of the PSD. Half of the cirrus cloud optical depth calculated from these in situ measurements can be due to this shattering phenomenon. Another challenge is the determination of ice and liquid water amounts in mixed phase clouds. Mixed phase clouds in the Arctic contain mostly liquid water, and the presence of ice is important for determining their lifecycle. Colder high clouds between -20 and -36 oC may also be mixed phase but in this case their condensate is mostly ice with low levels of liquid water. Rather than affecting their lifecycle, the presence of liquid dramatically affects the cloud optical properties, which affects cloud-climate feedback processes in GCMs. This project has made advancements in solving both of these problems. Regarding the first problem, PSD in ice clouds are uncertain due to the inability to reliably measure the concentrations of the smallest crystals (D < 100 m), known as the small mode. Rather than using in situ probe measurements aboard aircraft, we employed a treatment of ice cloud optical properties formulated in terms of PSD parameters in combination with remote measurements of thermal radiances to characterize the small mode. This is possible since the absorption efficiency (Qabs) of small mode crystals is larger at 12 m wavelength relative to 11 m wavelength due to the process of wave resonance or photon tunneling more active at 12 m. This makes the 12/11 m absorption optical depth ratio (or equivalently the 12/11 m Qabs ratio) a means for detecting the relative concentration of small ice particles in cirrus. Using this principle, this project tested and developed PSD schemes that can help characterize cirrus clouds at each of the three ARM sites: SGP, NSA and TWP. This was the main effort of this project. These PSD schemes and ice sedimentation velocities predicted from them have been used to test the new cirrus microphysics parameterization in the GCM known as the Community Climate Systems Model (CCSM) as part of an ongoing collaboration with NCAR. Regarding the second problem, we developed and did preliminary testing on a passive thermal method for retrieving the total water path (TWP) of Arctic mixed phase clouds where TWPs are often in the range of 20 to 130 g m-2 (difficult for microwave radiometers to accurately measure). We also developed a new radar method for retrieving the cloud ice water content (IWC), which can be vertically integrated to yield the ice water path (IWP). These techniques were combined to determine the IWP and liquid water path (LWP) in Arctic clouds, and hence the fraction of ice and liquid water. We have tested this approach using a case study from the ARM field campaign called M-PACE (Mixed-Phase Arctic Cloud Experiment). This research led to a new satellite remote sensing method that appears promising for detecting low levels of liquid water in high clouds typically between -20 and -36 oC. We hope to develop this method in future research.

  20. LABORATORY STUDIES ON THE FORMATION OF FORMIC ACID (HCOOH) IN INTERSTELLAR AND COMETARY ICES

    SciTech Connect (OSTI)

    Bennett, Chris J.; Kim, Yong Seol; Kaiser, Ralf I.; Hama, Tetsuya; Kawasaki, Masahiro

    2011-01-20

    Mixtures of water (H{sub 2}O) and carbon monoxide (CO) ices were irradiated at 10 K with energetic electrons to simulate the energy transfer processes that occur in the track of galactic cosmic-ray particles penetrating interstellar ices. We identified formic acid (HCOOH) through new absorption bands in the infrared spectra at 1690 and 1224 cm{sup -1} (5.92 and 8.17 {mu}m, respectively). During the subsequent warm-up of the irradiated samples, formic acid is evident from the mass spectrometer signal at the mass-to-charge ratio, m/z = 46 (HCOOH{sup +}) as the ice sublimates. The detection of formic acid was confirmed using isotopically labeled water-d2 with carbon monoxide, leading to formic acid-d2 (DCOOD). The temporal fits of the reactants, reaction intermediates, and products elucidate two reaction pathways to formic acid in carbon monoxide-water ices. The reaction is induced by unimolecular decomposition of water forming atomic hydrogen (H) and the hydroxyl radical (OH). The dominating pathway to formic acid (HCOOH) was found to involve addition of suprathermal hydrogen atoms to carbon monoxide forming the formyl radical (HCO); the latter recombined with neighboring hydroxyl radicals to yield formic acid (HCOOH). To a lesser extent, hydroxyl radicals react with carbon monoxide to yield the hydroxyformyl radical (HOCO), which recombined with atomic hydrogen to produce formic acid. Similar processes are expected to produce formic acid within interstellar ices, cometary ices, and icy satellites, thus providing alternative processes for the generation of formic acid whose abundance in hot cores such as Sgr-B2 cannot be accounted for solely by gas-phase chemistry.

  1. {sup 39}Ar Detection at the 10{sup -16} Isotopic Abundance Level with Atom Trap Trace Analysis

    SciTech Connect (OSTI)

    Jiang, W.; Williams, W.; Bailey, K.; O'Connor, T. P.; Mueller, P.; Davis, A. M.; Hu, S.-M.; Sun, Y. R.; Lu, Z.-T.; Purtschert, R.; Sturchio, N. C.

    2011-03-11

    Atom trap trace analysis, a laser-based atom counting method, has been applied to analyze atmospheric {sup 39}Ar (half-life=269 yr), a cosmogenic isotope with an isotopic abundance of 8x10{sup -16}. In addition to the superior selectivity demonstrated in this work, the counting rate and efficiency of atom trap trace analysis have been improved by 2 orders of magnitude over prior results. The significant applications of this new analytical capability lie in radioisotope dating of ice and water samples and in the development of dark matter detectors.

  2. Stellar abundances in the solar neighborhood: The Hypatia Catalog (Journal

    Office of Scientific and Technical Information (OSTI)

    Article) | SciTech Connect Stellar abundances in the solar neighborhood: The Hypatia Catalog Citation Details In-Document Search Title: Stellar abundances in the solar neighborhood: The Hypatia Catalog We compile spectroscopic abundance data from 84 literature sources for 50 elements across 3058 stars in the solar neighborhood, within 150 pc of the Sun, to produce the Hypatia Catalog. We evaluate the variability of the spread in abundance measurements reported for the same star by different

  3. NN inversion potentials intermediate energy proton-nucleus elastic scattering

    SciTech Connect (OSTI)

    Arellano, H.F.; Brieva, F.A.; Love, W.G.; Geramb, H.V. von

    1995-10-01

    Recently developed nucleon-nucleon interactions using the quantum inverse scattering method shed new fight on the off-shell properties of the internucleon effective force for nucleon-nucleus scattering. Calculations of proton elastic scattering from {sup 40}Ca and {sup 208}Pb in the 500 MeV region show that variations in off-shell contributions are determined to a great extent by the accuracy with which the nucleon-nucleon phase shifts are reproduced. The study is based on the full-folding approach to the nucleon-nucleus optical potential which allows a deep understanding of the interplay between on- and off-shell effects in nucleon scattering. Results and the promising extension offered by the inversion potentials beyond the range of validity of the low-energy internucleon forces will be discussed.

  4. Methods and compositions for targeting macromolecules into the nucleus

    DOE Patents [OSTI]

    Chook, Yuh Min

    2013-06-25

    The present invention includes compositions, methods and kits for directing an agent across the nuclear membrane of a cell. The present invention includes a Karyopherin beta2 translocation motif in a polypeptide having a slightly positively charged region or a slightly hydrophobic region and one or more R/K/H-X.sub.(2-5)-P-Y motifs. The polypeptide targets the agent into the cell nucleus.

  5. AN OFF-CENTERED ACTIVE GALACTIC NUCLEUS IN NGC3115

    SciTech Connect (OSTI)

    Menezes, R. B.; Steiner, J. E.; Ricci, T. V.

    2014-11-20

    NGC3115 is an S0 galaxy that has always been considered to have a pure absorption-line spectrum. Some recent studies have detected a compact radio-emitting nucleus in this object, coinciding with the photometric center and with a candidate for the X-ray nucleus. This is evidence of the existence of a low-luminosity active galactic nucleus (AGN) in the galaxy, although no emission line has ever been observed. We report the detection of an emission-line spectrum of a type 1 AGN in NGC3115, with an H? luminosity of L {sub H?} = (4.2 0.4) 10{sup 37} erg s{sup 1}. Our analysis revealed that this AGN is located at a projected distance of ?0.''29 0.''05 (corresponding to ?14.3 2.5 pc) from the stellar bulge center, which is coincident with the kinematic center of this object's stellar velocity map. The black hole corresponding to the observed off-centered AGN may form a binary system with a black hole located at the stellar bulge center. However, it is also possible that the displaced black hole is the merged remnant of the binary system coalescence, after the ''kick'' caused by the asymmetric emission of gravitational waves. We propose that certain features in the stellar velocity dispersion map are the result of perturbations caused by the off-centered AGN.

  6. Superscaling in electron-nucleus scattering and its link to CC and NC QE neutrino-nucleus scattering

    SciTech Connect (OSTI)

    Barbaro, M. B.; Amaro, J. E.; Caballero, J. A.; González-Jiménez, R.; Donnelly, T. W.; Ivanov, M.; Udías, J. M.

    2015-05-15

    The superscaling approach (SuSA) to neutrino-nucleus scattering, based on the assumed universality of the scaling function for electromagnetic and weak interactions, is reviewed. The predictions of the SuSA model for bot CC and NC differential and total cross sections are presented and compared with the MiniBooNE data. The role of scaling violations, in particular the contribution of meson exchange currents in the two-particle two-hole sector, is explored.

  7. Molecular simulations of heterogeneous ice nucleation. I. Controlling ice nucleation through surface hydrophilicity

    SciTech Connect (OSTI)

    Cox, Stephen J.; Kathmann, Shawn M.; Slater, B.; Michaelides, Angelos

    2015-05-14

    Ice formation is one of the most common and important processes on earth and almost always occurs at the surface of a material. A basic understanding of how the physicochemical properties of a material’s surface affect its ability to form ice has remained elusive. Here, we use molecular dynamics simulations to directly probe heterogeneous ice nucleation at a hexagonal surface of a nanoparticle of varying hydrophilicity. Surprisingly, we find that structurally identical surfaces can both inhibit and promote ice formation and analogous to a chemical catalyst, it is found that an optimal interaction between the surface and the water exists for promoting ice nucleation.We use our microscopic understanding of the mechanism to design a modified surface in silico with enhanced ice nucleating ability. C 2015 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution 3.0 Unported License.

  8. The influence of ice nucleation mode and ice vapor growth on simulation of

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    arctic mixed-phase clouds The influence of ice nucleation mode and ice vapor growth on simulation of arctic mixed-phase clouds Avramov, Alexander The Pennsylvania State University Category: Modeling Mixed-phase arctic stratus clouds are the predominant cloud type in the Arctic . Perhaps one of the most intriguing of their features is that they tend to have liquid tops that precipitate ice. Despite the fact that this situation is colloidally unstable, these cloud systems are quite long lived

  9. A Smoothed Particle Hydrodynamics Model for Ice Sheet and Ice Shelf Dynamics

    SciTech Connect (OSTI)

    Pan, Wenxiao; Tartakovsky, Alexandre M.; Monaghan, Joseph J.

    2012-02-08

    Mathematical modeling of ice sheets is complicated by the non-linearity of the governing equations and boundary conditions. Standard grid-based methods require complex front tracking techniques and have limited capability to handle large material deformations and abrupt changes in bottom topography. As a consequence, numerical methods are usually restricted to shallow ice sheet and ice shelf approximations. We propose a new smoothed particle hydrodynamics (SPH) model for coupled ice sheet and ice shelf dynamics. SPH is a fully Lagrangian particle method. It is highly scalable and its Lagrangian nature and meshless discretization are well suited to the simulation of free surface flows, large material deformation, and material fragmentation. In this paper SPH is used to study ice sheet/ice shelf behavior, and the dynamics of the grounding line. The steady state position of the grounding line obtained from the SPH simulations is in good agreement with laboratory observations for a wide range of simulated bedrock slopes, and density ratios similar to those of ice and sea water. The numerical accuracy of the SPH algorithm is further verified by simulating the plane shear flow of two immiscible fluids and the propagation of a highly viscous blob of fluid along a horizontal surface. In the experiment, the ice was represented with a viscous newtonian fluid. For consistency, in the described SPH model the ice is also modeled as a viscous newtonian fluid. Typically, ice sheets are modeled as a non-Newtonian fluid, accounting for the changes in the mechanical properties of ice. Implementation of a non-Newtonian rheology in the SPH model is the subject of our ongoing research.

  10. Smoothed particle hydrodynamics Non-Newtonian model for ice-sheet and ice-shelf dynamics

    SciTech Connect (OSTI)

    Pan, Wenxiao; Tartakovsky, Alexandre M.; Monaghan, Joseph J.

    2013-06-01

    Mathematical modeling of ice sheets is complicated by the non-linearity of the governing equations and boundary conditions. Standard grid-based methods require complex front tracking techniques and have limited capability to handle large material deformations and abrupt changes in bottom topography. As a consequence, numerical methods are usually restricted to shallow ice sheet and ice shelf approximations. We propose a new smoothed particle hydrodynamics (SPH) non-Newtonian model for coupled ice sheet and ice shelf dynamics. SPH, a fully Lagrangian particle method, is highly scalable and its Lagrangian nature and meshless discretization are well suited to the simulation of free surface ?ows, large material deformation, and material fragmentation. In this paper, SPH is used to study 3D ice sheet/ice shelf behavior, and the dynamics of the grounding line. The steady state position of the grounding line obtained from SPH simulations is in good agreement with laboratory observations for a wide range of simulated bedrock slopes, and density ratios, similar to those of ice and sea water. The numerical accuracy of the SPH algorithm is veri?ed by simulating Poiseuille ?ow, plane shear ?ow with free surface and the propagation of a blob of ice along a horizontal surface. In the laboratory experiment, the ice was represented with a viscous Newtonian ?uid. In the present work, however, the ice is modeled as both viscous Newtonian ?uid and non-Newtonian ?uid, such that the e?ect of non-Newtonian rheology on the dynamics of grounding line was examined. The non-Newtonian constitutive relation is prescribed to be Glens law for the creep of polycrystalline ice. A V-shaped bedrock ramp is further introduced to model the real geometry of bedrock slope.

  11. Communication: On the stability of ice 0, ice i, and I{sub h}

    SciTech Connect (OSTI)

    Quigley, D.; Alf, D.; Slater, B.

    2014-10-28

    Using ab initio methods, we examine the stability of ice 0, a recently proposed tetragonal form of ice implicated in the homogeneous freezing of water [J. Russo, F. Romano, and H. Tanaka, Nat. Mater. 13, 670 (2014)]. Vibrational frequencies are computed across the complete Brillouin Zone using Density Functional Theory (DFT), to confirm mechanical stability and quantify the free energy of ice 0 relative to ice I{sub h}. The robustness of this result is tested via dispersion corrected semi-local and hybrid DFT, and Quantum Monte-Carlo calculation of lattice energies. Results indicate that popular molecular models only slightly overestimate the stability of ice zero. In addition, we study all possible realisations of proton disorder within the ice zero unit cell, and identify the ground state as ferroelectric. Comparisons are made to other low density metastable forms of ice, suggesting that the ice i structure [C. J. Fennel and J. D. Gezelter, J. Chem. Theory Comput. 1, 662 (2005)] may be equally relevant to ice formation.

  12. Developing and Evaluating Ice Cloud Parameterizations by

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    by remote sensing is that the transfer functions which relate the observables (e. g., radar Doppler spectrum) to cloud properties (e. g., ice water content, or IWC) are not...

  13. Climate, Ocean and Sea Ice Modeling (COSIM)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    ... Sea Level Rise: The rate of sea level rise is one of the largest unknowns in current climate models and requires our advanced ocean and ice sheet models for accurate future ...

  14. Climate, Ocean and Sea Ice Modeling

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    The rate of sea level rise is one of the largest unknowns in current climate models and requires our advanced ocean and ice sheet models for accurate future projections. * Rapid ...

  15. Spreading of oil spilled under ice

    SciTech Connect (OSTI)

    Yapa, P.D.; Chowdhury, T. )

    1990-12-01

    A new set of equations is presented to describe the process of oil spreading under ice in clam waters. These equations consider the gravity (buoyancy)-inertia phase, the gravity (buoyancy)-viscous phase, and the termination of spreading during the buoyancy-surface-tension phase. The derivation considers both the constant discharge mode and the constant volume mode. Therefore, a complete description of the spreading phenomena from the time of initial spill to the termination of spreading is presented. Laboratory experiments were conducted using both real ice covers in a cold room and artificial ice covers. The experiments included different ice-cover roughnesses from smooth to rough, oils of different viscosities, and a variety of discharge conditions. The experimental data show close agreement with the theory. These equations can be used during cleanup or environmental impact assessment to estimate the area of an oil slick with respect to time.

  16. The Next ICE Age | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    technologies to further increase engine efficiency and external drivers PDF icon deer12_foster.pdf More Documents & Publications The Next ICE Age Fuel Modification t Facilitate Future Combustion Regimes? Optimization of Advanced Diesel Engine Combustion Strategies

  17. Alternative Fuels Data Center: Electric Ice Resurfacers Improve Air Quality

    Alternative Fuels and Advanced Vehicles Data Center [Office of Energy Efficiency and Renewable Energy (EERE)]

    in Minnesota Electric Ice Resurfacers Improve Air Quality in Minnesota to someone by E-mail Share Alternative Fuels Data Center: Electric Ice Resurfacers Improve Air Quality in Minnesota on Facebook Tweet about Alternative Fuels Data Center: Electric Ice Resurfacers Improve Air Quality in Minnesota on Twitter Bookmark Alternative Fuels Data Center: Electric Ice Resurfacers Improve Air Quality in Minnesota on Google Bookmark Alternative Fuels Data Center: Electric Ice Resurfacers Improve Air

  18. Pollution Changes Clouds' Ice Crystal Genesis

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Pollution Changes Clouds' Ice Crystal Genesis For original submission and image(s), see ARM Research Highlights http://www.arm.gov/science/highlights/ Research Highlight Suspended high in the atmosphere, plentiful dust particles are fertile turf for growing ice. But, what are the optimal conditions for this crop? Researchers at Pacific Northwest National Laboratory (PNNL) found that miniscule particles of airborne dust, thought to be a perfect landing site for water vapor, are altered by the

  19. High-Performance Thermoelectric Devices Based on Abundant Silicide...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Development of high-performance thermoelectric devices for vehicle waste heat recovery will include fundamental research to use abundant promising low-cost thermoelectric...

  20. Discovery of bridgmanite, the most abundant mineral in Earth...

    Office of Scientific and Technical Information (OSTI)

    SciTech Connect Search Results Journal Article: Discovery of bridgmanite, the most abundant mineral in Earth, in a shocked meteorite Citation Details In-Document Search Title: ...

  1. Deformations and magnetic rotations in the {sup 60}Ni nucleus

    SciTech Connect (OSTI)

    Torres, D. A.; Cristancho, F.; Andersson, L.-L.; Johansson, E. K.; Rudolph, D.; Fahlander, C.; Ekman, J.; Rietz, R. du; Andreoiu, C.; Carpenter, M. P.; Seweryniak, D.; Zhu, S.; Charity, R. J.; Chiara, C. J.; Hoel, C.; Pechenaya, O. L.; Reviol, W.; Sarantites, D. G.; Sobotka, L. G.; Baktash, C.

    2008-11-15

    Data from three experiments using the heavy-ion fusion evaporation-reaction {sup 36}Ar+{sup 28}Si have been combined to study high-spin states in the residual nucleus {sup 60}Ni, which is populated via the evaporation of four protons from the compound nucleus {sup 64}Ge. The GAMMASPHERE array was used for all the experiments in conjunction with a 4{pi} charged-particle detector arrays (MICROBALL, LUWUSIA) and neutron detectors (NEUTRON SHELL) to allow for the detection of {gamma} rays in coincidence with the evaporated particles. An extended {sup 60}Ni level scheme is presented, comprising more than 270{gamma}-ray transitions and 110 excited states. Their spins and parities have been assigned via directional correlations of {gamma} rays emitted from oriented states. Spherical shell-model calculations in the fp-shell characterize some of the low-spin states, while the experimental results of the rotational bands are analyzed with configuration-dependent cranked Nilsson-Strutinsky calculations.

  2. Coulomb Excitation of the N = 50 nucleus {sup 80}Zn

    SciTech Connect (OSTI)

    Van de Walle, J.; Cocolios, T. E.; Huyse, M.; Ivanov, O.; Mayet, P.; Raabe, R.; Sawicka, M.; Stefanescu, I.; Duppen, P. van; Aksouh, F.; Behrens, T.; Gernhauser, R.; Kroell, T.; Kruecken, R.; Bildstein, V.; Blazhev, A.; Eberth, J.

    2008-05-12

    Neutron rich Zinc isotopes, including the N = 50 nucleus {sup 80}Zn, were produced and post-accelerated at the Radioactive Ion Beam (RIB) facility REX-ISOLDE (CERN). Low-energy Coulomb excitation was induced on these isotopes after post-acceleration, yielding B(E2) strengths to the first excited 2{sup +} states. For the first time, an excited state in {sup 80}Zn was observed and the 2{sub 1}{sup +} state in {sup 78}Zn was established. The measured B(E2,2{sub 1}{sup +}{yields}0{sub 1}{sup +}) values are compared to two sets of large scale shell model calculations. Both calculations reproduce the observed B(E2) systematics for the full Zinc isotopic chain. The results for N = 50 isotones indicate a good N = 50 shell closure and a strong Z = 28 proton core polarization. The new results serve as benchmarks to establish theoretical models, predicting the nuclear properties of the doubly magic nucleus {sup 78}Ni.

  3. Soft X-ray irradiation of methanol ice: Formation of products as a function of photon energy

    SciTech Connect (OSTI)

    Chen, Y.-J.; Juang, K.-J.; Yih, T.-S.; Ciaravella, A.; Cecchi-Pestellini, C.; Muoz Caro, G. M.; Jimnez-Escobar, A.

    2013-12-01

    Pure methanol ices have been irradiated with monochromatic soft X-rays of 300 and 550 eV close to the 1s resonance edges of C and O, respectively, and with a broadband spectrum (250-1200 eV). The infrared (IR) spectra of the irradiated ices show several new products of astrophysical interest such as CH{sub 2}OH, H{sub 2}CO, CH{sub 4}, HCOOH, HCOCH{sub 2}OH, CH{sub 3}COOH, CH{sub 3}OCH{sub 3}, HCOOCH{sub 3}, and (CH{sub 2}OH){sub 2}, as well as HCO, CO, and CO{sub 2}. The effect of X-rays is the result of the combined interactions of photons and electrons with the ice. A significant contribution to the formation and growth of new species in the CH{sub 3}OH ice irradiated with X-rays is given by secondary electrons, whose energy distribution depends on the energy of X-ray photons. Within a single experiment, the abundances of the new products increase with the absorbed energy. Monochromatic experiments show that product abundances also increase with the photon energy. However, the abundances per unit energy of newly formed species show a marked decrease in the broadband experiment as compared to irradiations with monochromatic photons, suggesting a possible regulatory role of the energy deposition rate. The number of new molecules produced per absorbed eV in the X-ray experiments has been compared to those obtained with electron and ultraviolet (UV) irradiation experiments.

  4. The Role of Snow and Ice in the Climate System

    SciTech Connect (OSTI)

    Barry, Roger G.

    2007-12-19

    Global snow and ice cover (the 'cryosphere') plays a major role in global climate and hydrology through a range of complex interactions and feedbacks, the best known of which is the ice - albedo feedback. Snow and ice cover undergo marked seasonal and long term changes in extent and thickness. The perennial elements - the major ice sheets and permafrost - play a role in present-day regional and local climate and hydrology, but the large seasonal variations in snow cover and sea ice are of importance on continental to hemispheric scales. The characteristics of these variations, especially in the Northern Hemisphere, and evidence for recent trends in snow and ice extent are discussed.

  5. Ice Bear® Storage Module | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Ice Bear® Storage Module Ice Bear® Storage Module Thermal Energy Storage for Light Commercial Refrigerant-Based Air Conditioning Units The Ice Bear® storage technology was initially developed by Powell Energy Products, with assistance from DOE's Inventions and Innovation Program and commercialized by Ice Energy®, Inc. The Ice Bear storage module was engineered to complement new or existing air conditioning (AC) equipment to shift energy use from peak to off-peak periods. The Ice Bear unit is

  6. The Role of Snow and Ice in the Climate System

    ScienceCinema (OSTI)

    Barry, Roger G.

    2009-09-01

    Global snow and ice cover (the 'cryosphere') plays a major role in global climate and hydrology through a range of complex interactions and feedbacks, the best known of which is the ice - albedo feedback. Snow and ice cover undergo marked seasonal and long term changes in extent and thickness. The perennial elements - the major ice sheets and permafrost - play a role in present-day regional and local climate and hydrology, but the large seasonal variations in snow cover and sea ice are of importance on continental to hemispheric scales. The characteristics of these variations, especially in the Northern Hemisphere, and evidence for recent trends in snow and ice extent are discussed.

  7. The lithium abundances of a large sample of red giants

    SciTech Connect (OSTI)

    Liu, Y. J.; Tan, K. F.; Wang, L.; Zhao, G.; Li, H. N.; Sato, Bun'ei; Takeda, Y. E-mail: gzhao@nao.cas.cn

    2014-04-20

    The lithium abundances for 378 G/K giants are derived with non-local thermodynamic equilibrium correction considered. Among these are 23 stars that host planetary systems. The lithium abundance is investigated, as a function of metallicity, effective temperature, and rotational velocity, as well as the impact of a giant planet on G/K giants. The results show that the lithium abundance is a function of metallicity and effective temperature. The lithium abundance has no correlation with rotational velocity at v sin i < 10 km s{sup 1}. Giants with planets present lower lithium abundance and slow rotational velocity (v sin i < 4 km s{sup 1}). Our sample includes three Li-rich G/K giants, 36 Li-normal stars, and 339 Li-depleted stars. The fraction of Li-rich stars in this sample agrees with the general rate of less than 1% in the literature, and the stars that show normal amounts of Li are supposed to possess the same abundance at the current interstellar medium. For the Li-depleted giants, Li-deficiency may have already taken place at the main sequence stage for many intermediate mass (1.5-5 M {sub ?}) G/K giants. Finally, we present the lithium abundance and kinematic parameters for an enlarged sample of 565 giants using a compilation of the literature, and confirm that the lithium abundance is a function of metallicity and effective temperature. With the enlarged sample, we investigate the differences between the lithium abundance in thin-/thick-disk giants, which indicate that the lithium abundance in thick-disk giants is more depleted than that in thin-disk giants.

  8. Land Ice Verification and Validation Kit

    Energy Science and Technology Software Center (OSTI)

    2015-07-15

    To address a pressing need to better understand the behavior and complex interaction of ice sheets within the global Earth system, significant development of continental-scale, dynamical ice-sheet models is underway. The associated verification and validation process of these models is being coordinated through a new, robust, python-based extensible software package, the Land Ice Verification and Validation toolkit (LIVV). This release provides robust and automated verification and a performance evaluation on LCF platforms. The performance V&Vmore » involves a comprehensive comparison of model performance relative to expected behavior on a given computing platform. LIVV operates on a set of benchmark and test data, and provides comparisons for a suite of community prioritized tests, including configuration and parameter variations, bit-4-bit evaluation, and plots of tests where differences occur.« less

  9. Land Ice Verification and Validation Kit

    SciTech Connect (OSTI)

    2015-07-15

    To address a pressing need to better understand the behavior and complex interaction of ice sheets within the global Earth system, significant development of continental-scale, dynamical ice-sheet models is underway. The associated verification and validation process of these models is being coordinated through a new, robust, python-based extensible software package, the Land Ice Verification and Validation toolkit (LIVV). This release provides robust and automated verification and a performance evaluation on LCF platforms. The performance V&V involves a comprehensive comparison of model performance relative to expected behavior on a given computing platform. LIVV operates on a set of benchmark and test data, and provides comparisons for a suite of community prioritized tests, including configuration and parameter variations, bit-4-bit evaluation, and plots of tests where differences occur.

  10. Semi-inclusive charged-current neutrino-nucleus reactions

    SciTech Connect (OSTI)

    Moreno, O.; Donnelly, T. W.; Van Orden, J. W.; Ford, W. P.

    2014-07-17

    The general, universal formalism for semi-inclusive charged-current (anti)neutrino-nucleus reactions is given for studies of any hadronic system, namely, either nuclei or the nucleon itself. The detailed developments are presented with the former in mind and are further specialized to cases where the final-state charged lepton and an ejected nucleon are presumed to be detected. General kinematics for such processes are summarized and then explicit expressions are developed for the leptonic and hadronic tensors involved and for the corresponding responses according to the usual charge, longitudinal and transverse projections, keeping finite the masses of all particles involved. In the case of the hadronic responses, general symmetry principles are invoked to determine which contributions can occur. As a result, the general leptonic-hadronic tensor contraction is given as well as the cross section for the process.

  11. Semi-inclusive charged-current neutrino-nucleus reactions

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Moreno, O.; Donnelly, T. W.; Van Orden, J. W.; Ford, W. P.

    2014-07-17

    The general, universal formalism for semi-inclusive charged-current (anti)neutrino-nucleus reactions is given for studies of any hadronic system, namely, either nuclei or the nucleon itself. The detailed developments are presented with the former in mind and are further specialized to cases where the final-state charged lepton and an ejected nucleon are presumed to be detected. General kinematics for such processes are summarized and then explicit expressions are developed for the leptonic and hadronic tensors involved and for the corresponding responses according to the usual charge, longitudinal and transverse projections, keeping finite the masses of all particles involved. In the case ofmore » the hadronic responses, general symmetry principles are invoked to determine which contributions can occur. As a result, the general leptonic-hadronic tensor contraction is given as well as the cross section for the process.« less

  12. One-pion production in neutrino-nucleus collisions

    SciTech Connect (OSTI)

    Hernndez, E.; Nieves, J.; Vicente-Vacas, J. M.

    2015-05-15

    We use our model for neutrino pion production on the nucleon to study pion production on a nucleus. The model is conveniently modified to include in-medium corrections and its validity is extended up to 2 GeV neutrino energies by the inclusion of new resonant contributions in the production process. Our results are compared with recent MiniBooNE data measured in mineral oil. Our total cross sections are below data for neutrino energies above ? 1 GeV. As with other theoretical calculations, the agreement with data improves if we neglect pion final state interaction. This is also the case for differential cross sections convoluted over the neutrino flux.

  13. Energy conservation in ice skating rinks

    SciTech Connect (OSTI)

    Dietrich, B.K.; McAvoy, T.J.

    1980-01-01

    An economic and energy analysis of ice rinks was made to examine the areas in which energy could be profitably conserved. The areas where new equipment could make a major reduction in energy use are: the use of waste heat for space heating, the installation of a low emissivity false ceiling to reduce radiant heat, the use of a load cycling controller to reduce refrigeration costs, and the installation of more efficient lighting systems. Changes in rink operating procedure that could cut energy use are: higher refrigerant temperatures, thinner ice, the use of colder resurfacing water, turning the compressors and pumps off at night, and reducing ventilation.

  14. Flight Path 30L - About ICE House

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    L The shape of the neutron spectrum here is very similar to that of neutrons produced in the atmosphere by cosmic rays but with a neutron flux a million times higher, depending on altitude. This large flux allows testing of semiconductor devices at greatly accelerated rates. About ICE House Irradiation of Chips Electronics (ICE House) is located on the 30° flight path of WNR. At this angle, the shape of the neutron spectrum here is very similar to that of neutrons produced in the atmosphere by

  15. Ice Sheet Model Reveals Most Comprehensive Projections for West...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    has been stage to dramatic thinning in recent years. The West Antarctic Ice Sheet (WAIS) is out of balance because it is losing significant amounts of ice to the ocean, with...

  16. A TWP-ICE High-Level Cloud Case Study

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    A TWP-ICE High-Level Cloud Case Study Mace, Gerald University of Utah Category: Field Campaigns The Tropical Warm Pool International Cloud Experiment (TWP ICE) was conducted near...

  17. Covered Product Category: Water-Cooled Ice Machines

    Broader source: Energy.gov [DOE]

    The Federal Energy Management Program (FEMP) provides acquisition guidance and federal efficiency requirements for water-cooled ice machines.

  18. ARM - What About Melting Polar Ice Caps and Sea Levels?

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    What About Melting Polar Ice Caps and Sea Levels? Outreach Home Room News Publications Traditional Knowledge Kiosks Barrow, Alaska Tropical Western Pacific Site Tours Contacts Students Study Hall About ARM Global Warming FAQ Just for Fun Meet our Friends Cool Sites Teachers Teachers' Toolbox Lesson Plans What About Melting Polar Ice Caps and Sea Levels? As the northern polar zone warms up, sea ice could melt (very probable) and the sea/ice interface could retreat to the north. This is likely to

  19. Stellar abundances in the solar neighborhood: The Hypatia Catalog

    SciTech Connect (OSTI)

    Hinkel, Natalie R.; Timmes, F.X.; Young, Patrick A.; Pagano, Michael D.; Turnbull, Margaret C.

    2014-09-01

    We compile spectroscopic abundance data from 84 literature sources for 50 elements across 3058 stars in the solar neighborhood, within 150 pc of the Sun, to produce the Hypatia Catalog. We evaluate the variability of the spread in abundance measurements reported for the same star by different surveys. We also explore the likely association of the star within the Galactic disk, the corresponding observation and abundance determination methods for all catalogs in Hypatia, the influence of specific catalogs on the overall abundance trends, and the effect of normalizing all abundances to the same solar scale. The resulting stellar abundance determinations in the Hypatia Catalog are analyzed only for thin-disk stars with observations that are consistent between literature sources. As a result of our large data set, we find that the stars in the solar neighborhood may reveal an asymmetric abundance distribution, such that a [Fe/H]-rich group near the midplane is deficient in Mg, Si, S, Ca, Sc II, Cr II, and Ni as compared to stars farther from the plane. The Hypatia Catalog has a wide number of applications, including exoplanet hosts, thick- and thin-disk stars, and stars with different kinematic properties.

  20. Therapeutic Hypothermia: Protective Cooling Using Medical Ice Slurry |

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Argonne National Laboratory Therapeutic Hypothermia: Protective Cooling Using Medical Ice Slurry Technology available for licensing: Proprietary method and equipment for making an ice slurry coolant to induce therapeutic hypothermia. Portable, automatic Advantageous for emergency care, cooling during surgeries, organ harvesting PDF icon ice_slurry

  1. The Next ICE Age | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    developments in diesel engines for light- and heavy-duty applications PDF icon deer12_ruth.pdf More Documents & Publications The Next ICE Age Cummins SuperTruck Program - Technology and System Level Demonstration of Highly Efficient and Clean, Diesel Powered Class 8 Trucks SuperTruck Program: Engine Project Review

  2. Extended Glauber Model of Antiproton-Nucleus Annihilation for All Energies and Mass Numbers

    SciTech Connect (OSTI)

    Lee, Teck-Ghee; Wong, Cheuk-Yin

    2014-01-01

    Previous analytical formulas in the Glauber model for high-energy nucleus-nucleus collisions developed by Wong are utilized and extended to study Antiproton-nucleus annihilations for both high and low energies, after taking into account the effects of Coulomb and nuclear interactions, and the change of the antiproton momentum inside a nucleus. The extended analytical formulas capture the main features of the experimental antiproton-nucleus annihilation cross sections for all energies and mass numbers. At high antiproton energies, they exhibit the granular property for the lightest nuclei and the black-disk limit for the heavy nuclei. At low antiproton energies, they display the effect of the antiproton momentum increase due to the nuclear interaction for the light nuclei, and the effect of the magnification due to the attractive Coulomb interaction for the heavy nuclei.

  3. Managing an Abundant Resource: An Interview with Paula Gant

    Broader source: Energy.gov [DOE]

    Paula Gant, Deputy Assistant Secretary for the Office of Oil and Gas in the Energy Department's Office of Fossil Energy, discusses challenges posed by the new abundance of fossil fuels made possible by the hydraulic fracturing boom.

  4. Redox Active Catalysts Utilizing Earth Abundant Metals | Center...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Redox Active Catalysts Utilizing Earth Abundant Metals 14 Mar 2014 Ryan Trovitch has recently joined the team of the BISfuel PIs. He is an Assistant Professor at the Department of...

  5. Engineering Density of States of Earth Abundant Semiconductors for Enhanced

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Thermoelectric Power Factor | Department of Energy Density of States of Earth Abundant Semiconductors for Enhanced Thermoelectric Power Factor Engineering Density of States of Earth Abundant Semiconductors for Enhanced Thermoelectric Power Factor In highly mismatched semiconductor alloys, localized states of the impurities hybridize with energy bands of the host and lead to a density of states that can be optimally tuned to enhance the thermoelectric thermopower PDF icon wu.pdf More

  6. Stronger warming effects on microbial abundances in colder regions

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Chen, Ji; Luo, Yiqi; Xia, Jianyang; Jiang, Lifen; Zhou, Xuhui; Lu, Meng; Liang, Junyi; Shi, Zheng; Shelton, Shelby; Cao, Junji

    2015-12-10

    Soil microbes play critical roles in regulating terrestrial carbon (C) cycle and its feedback to climate change. However, it is still unclear how the soil microbial community and abundance respond to future climate change scenarios. In this meta-analysis, we synthesized the responses of microbial community and abundance to experimental warming from 64 published field studies. Our results showed that warming significantly increased soil microbial abundance by 7.6% on average. When grouped by vegetation or soil types, tundras and histosols had the strongest microbial responses to warming with increased microbial, fungal, and bacterial abundances by 15.0%, 9.5% and 37.0% in tundra,more » and 16.5%, 13.2% and 13.3% in histosols, respectively. We found significant negative relationships of the response ratios of microbial, fungal and bacterial abundances with the mean annual temperature, indicating that warming had stronger effects in colder than warmer regions. Moreover, the response ratios of microbial abundance to warming were positively correlated with those of soil respiration. Our results therefore indicate that the large quantities of C stored in colder regions are likely to be more vulnerable to climate warming than the soil C stored in other warmer regions.« less

  7. Modeling the Fracture of Ice Sheets on Parallel Computers

    SciTech Connect (OSTI)

    Waisman, Haim; Tuminaro, Ray

    2013-10-10

    The objective of this project was to investigate the complex fracture of ice and understand its role within larger ice sheet simulations and global climate change. This objective was achieved by developing novel physics based models for ice, novel numerical tools to enable the modeling of the physics and by collaboration with the ice community experts. At the present time, ice fracture is not explicitly considered within ice sheet models due in part to large computational costs associated with the accurate modeling of this complex phenomena. However, fracture not only plays an extremely important role in regional behavior but also influences ice dynamics over much larger zones in ways that are currently not well understood. To this end, our research findings through this project offers significant advancement to the field and closes a large gap of knowledge in understanding and modeling the fracture of ice sheets in the polar regions. Thus, we believe that our objective has been achieved and our research accomplishments are significant. This is corroborated through a set of published papers, posters and presentations at technical conferences in the field. In particular significant progress has been made in the mechanics of ice, fracture of ice sheets and ice shelves in polar regions and sophisticated numerical methods that enable the solution of the physics in an efficient way.

  8. HST/COS OBSERVATIONS OF GALACTIC HIGH-VELOCITY CLOUDS: FOUR ACTIVE GALACTIC NUCLEUS SIGHT LINES THROUGH COMPLEX C

    SciTech Connect (OSTI)

    Shull, J. Michael; Stevans, Matthew; Danforth, Charles; Penton, Steven V. [CASA, Department of Astrophysical and Planetary Sciences, University of Colorado, 389-UCB, Boulder, CO 80309 (United States); Lockman, Felix J. [National Radio Astronomy Observatory, Green Bank, WV 29444 (United States); Arav, Nahum, E-mail: michael.shull@colorado.edu, E-mail: matthew.stevans@colorado.edu, E-mail: charles.danforth@colorado.edu, E-mail: steven.penton@colorado.edu, E-mail: jlockman@nrao.edu, E-mail: arav@vt.edu [Department of Physics, Virginia Tech, Blacksburg, VA 24061 (United States)

    2011-10-01

    We report ultraviolet spectra of Galactic high-velocity clouds (HVCs) in Complex C, taken by the Cosmic Origins Spectrograph (COS) on the Hubble Space Telescope (HST), together with new 21 cm spectra from the Green Bank Telescope. The wide spectral coverage and higher signal-to-noise ratio, compared to previous HST spectra, provide better velocity definition of the HVC absorption, additional ionization species (including high ions), and improved abundances in this halo gas. Complex C has a metallicity of 10%-30% solar and a wide range of ions, suggesting dynamical and thermal interactions with hot gas in the Galactic halo. Spectra in the COS medium-resolution G130M (1133-1468 A) and G160M (1383-1796 A) gratings detect ultraviolet absorption lines from eight elements in low-ionization states (O I, N I, C II, S II, Si II, Al II, Fe II, P II) and three elements in intermediate- and high-ionization states (Si III, Si IV, C IV, N V). Our four active galactic nucleus sight lines toward Mrk 817, Mrk 290, Mrk 876, and PG 1259+593 have high-velocity H I and O VI column densities, log N{sub Hi}= 19.39-20.05 and log N{sub Ovi}= 13.58-14.10, with substantial amounts of kinematically associated photoionized gas. The high-ion abundance ratios are consistent with cooling interfaces between photoionized and collisionally ionized gas: N(C IV)/N(O VI) {approx} 0.3-0.5, N(Si IV)/N(O VI) {approx} 0.05-0.11, N(N V)/N(O VI) {approx} 0.07-0.13, and N(Si IV)/N(Si III) {approx}0.2.

  9. What Is the Size of the Atomic Nucleus? | U.S. DOE Office of Science (SC)

    Office of Science (SC) Website

    What Is the Size of the Atomic Nucleus? Nuclear Physics (NP) NP Home About Research Facilities Science Highlights Benefits of NP Funding Opportunities Nuclear Science Advisory Committee (NSAC) Community Resources Contact Information Nuclear Physics U.S. Department of Energy SC-26/Germantown Building 1000 Independence Ave., SW Washington, DC 20585 P: (301) 903-3613 F: (301) 903-3833 E: Email Us More Information » 02.29.16 What Is the Size of the Atomic Nucleus? The neutron skin of the nucleus

  10. H2 ICE Combustion | Argonne National Laboratory

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    H2 ICE Combustion Share Description Hydrogen combustion inside a direct injection H2 engine Topic Energy Energy efficiency Vehicles Hydrogen & fuel cells Credit S. Ciatti This video captures the OH * radicals that are produced during the hydrogen combustion process inside a direct injection H2 engine. It provides a qualitative assessment of where (areas in white, red, and green) and how rapidly those combustion reactions occur. The video was recorded at 3,000 RPM and with 6 bar indicated

  11. Flight Path 30L - ICE House

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Links The shape of the neutron spectrum here is very similar to that of neutrons produced in the atmosphere by cosmic rays but with a neutron flux a million times higher, depending on altitude. This large flux allows testing of semiconductor devices at greatly accelerated rates. The Invisible Neutron Threat LANSCE - A Key Facility for National Science and Defense Neutron-Induced Failures in Semiconductor Devices THE ICE HOUSE - Neutron Testing Leads to More-Reliable Electronic

  12. Flight Path 30L - ICE House

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Publications The shape of the neutron spectrum here is very similar to that of neutrons produced in the atmosphere by cosmic rays but with a neutron flux a million times higher, depending on altitude. This large flux allows testing of semiconductor devices at greatly accelerated rates. The Invisible Neutron Threat LANSCE - A Key Facility for National Science and Defense Neutron-Induced Failures in Semiconductor Devices THE ICE HOUSE - Neutron Testing Leads to More-Reliable Electronics

  13. Flight Path 30R - ICE II

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Links The shape of the neutron spectrum here is very similar to that of neutrons produced in the atmosphere by cosmic rays but with a neutron flux a million times higher, depending on altitude. This large flux allows testing of semiconductor devices at greatly accelerated rates. The Invisible Neutron Threat LANSCE - A Key Facility for National Science and Defense Neutron-Induced Failures in Semiconductor Devices THE ICE HOUSE - Neutron Testing Leads to More-Reliable Electronic

  14. Flight Path 30R - ICE II

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Publications The shape of the neutron spectrum here is very similar to that of neutrons produced in the atmosphere by cosmic rays but with a neutron flux a million times higher, depending on altitude. This large flux allows testing of semiconductor devices at greatly accelerated rates. The Invisible Neutron Threat LANSCE - A Key Facility for National Science and Defense Neutron-Induced Failures in Semiconductor Devices THE ICE HOUSE-Neutron Testing Leads to More-Reliable Electronics

  15. FactSheet-TWP_ICE.indd

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Warm Pool International Cloud Experiment General Description The Tropical Warm Pool - International Cloud Experiment (TWP-ICE) is a collaborative effort led by the U.S. Department of Energy's Atmospheric Radiation Measurement (ARM) Program and the Australian Bureau of Meteo- rology. Beginning January 19 and ending February 28, 2006, the experiment will be conducted in the region near the ARM Climate Research Facility in Darwin, Northern Australia. This permanent facility is fully equipped with

  16. Large Scale Ice Water Path and 3-D Ice Water Content

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Liu, Guosheng

    2008-01-15

    Cloud ice water concentration is one of the most important, yet poorly observed, cloud properties. Developing physical parameterizations used in general circulation models through single-column modeling is one of the key foci of the ARM program. In addition to the vertical profiles of temperature, water vapor and condensed water at the model grids, large-scale horizontal advective tendencies of these variables are also required as forcing terms in the single-column models. Observed horizontal advection of condensed water has not been available because the radar/lidar/radiometer observations at the ARM site are single-point measurement, therefore, do not provide horizontal distribution of condensed water. The intention of this product is to provide large-scale distribution of cloud ice water by merging available surface and satellite measurements. The satellite cloud ice water algorithm uses ARM ground-based measurements as baseline, produces datasets for 3-D cloud ice water distributions in a 10 deg x 10 deg area near ARM site. The approach of the study is to expand a (surface) point measurement to an (satellite) areal measurement. That is, this study takes the advantage of the high quality cloud measurements at the point of ARM site. We use the cloud characteristics derived from the point measurement to guide/constrain satellite retrieval, then use the satellite algorithm to derive the cloud ice water distributions within an area, i.e., 10 deg x 10 deg centered at ARM site.

  17. Large Scale Ice Water Path and 3-D Ice Water Content

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Liu, Guosheng

    Cloud ice water concentration is one of the most important, yet poorly observed, cloud properties. Developing physical parameterizations used in general circulation models through single-column modeling is one of the key foci of the ARM program. In addition to the vertical profiles of temperature, water vapor and condensed water at the model grids, large-scale horizontal advective tendencies of these variables are also required as forcing terms in the single-column models. Observed horizontal advection of condensed water has not been available because the radar/lidar/radiometer observations at the ARM site are single-point measurement, therefore, do not provide horizontal distribution of condensed water. The intention of this product is to provide large-scale distribution of cloud ice water by merging available surface and satellite measurements. The satellite cloud ice water algorithm uses ARM ground-based measurements as baseline, produces datasets for 3-D cloud ice water distributions in a 10 deg x 10 deg area near ARM site. The approach of the study is to expand a (surface) point measurement to an (satellite) areal measurement. That is, this study takes the advantage of the high quality cloud measurements at the point of ARM site. We use the cloud characteristics derived from the point measurement to guide/constrain satellite retrieval, then use the satellite algorithm to derive the cloud ice water distributions within an area, i.e., 10 deg x 10 deg centered at ARM site.

  18. Resonant vibrational energy transfer in ice Ih

    SciTech Connect (OSTI)

    Shi, L.; Li, F.; Skinner, J. L.

    2014-06-28

    Fascinating anisotropy decay experiments have recently been performed on H{sub 2}O ice Ih by Timmer and Bakker [R. L. A. Timmer, and H. J. Bakker, J. Phys. Chem. A 114, 4148 (2010)]. The very fast decay (on the order of 100 fs) is indicative of resonant energy transfer between OH stretches on different molecules. Isotope dilution experiments with deuterium show a dramatic dependence on the hydrogen mole fraction, which confirms the energy transfer picture. Timmer and Bakker have interpreted the experiments with a Frster incoherent hopping model, finding that energy transfer within the first solvation shell dominates the relaxation process. We have developed a microscopic theory of vibrational spectroscopy of water and ice, and herein we use this theory to calculate the anisotropy decay in ice as a function of hydrogen mole fraction. We obtain very good agreement with experiment. Interpretation of our results shows that four nearest-neighbor acceptors dominate the energy transfer, and that while the incoherent hopping picture is qualitatively correct, vibrational energy transport is partially coherent on the relevant timescale.

  19. Micro-Spectroscopic Imaging and Characterization of Individually Identified Ice Nucleating Particles from a Case Field Study

    SciTech Connect (OSTI)

    Knopf, Daniel A.; Alpert, Peter A.; Wang, Bingbing; O'Brien, Rachel E.; Kelly, Stephen T.; Laskin, Alexander; Gilles, Mary K.; Moffet, Ryan C.

    2014-09-03

    The effect of anthropogenic and biogenic organic particles on atmospheric glaciation processes is poorly understood. We use an optical microscopy (OM) setup to identify the location of ice nuclei (IN) active in immersion freezing and deposition ice nucleation for temperatures of 200-273 K within a large population of particles sampled from an ambient environment. Applying multi-modal micro-spectroscopy methods we characterize the physicochemical properties of individual IN in particle populations collected in central California. Chemical composition and mixing state analysis of particle populations are performed to identify characteristic particle-type classes. All particle-types contained organic material. Particles in these samples take up water at subsaturated conditions, induce immersion freezing at subsaturated and saturated conditions above 226 K, and act as deposition IN below 226 K. The identified IN belong to the most common particle-type classes observed in the field samples: organic coated sea salt, Na-rich, and secondary and refractory carbonaceous particles. Based on these observations, we suggest that the IN are not always particles with unique chemical composition and exceptional ice nucleation propensity; rather, they are common particles in the ambient particle population. Thus, particle composition and morphology alone are insufficient to assess their potential to act as IN. The results suggest that particle-type abundance is also a crucial factor in determining the ice nucleation efficiency of specific IN types. These findings emphasize that ubiquitous organic particles can induce ice nucleation under atmospherically relevant conditions and that they may play an important role in atmospheric glaciation processes.

  20. The chemical abundances of the Ap star HD94660

    SciTech Connect (OSTI)

    Giarrusso, M. [Universit di Catania, Dipartimento di Fisica e Astronomia, Sezione Astrofisica, Via S. Sofia 78, 95123 Catania (Italy); INAF - Osservatorio Astrofisico di Catania, via S. Sofia 78, 95123 Catania (Italy); INFN - Laboratori Nazionali del Sud (Italy)

    2014-05-09

    In this work I present the determination of chemical abundances of the Ap star HD94660, a possible rapid oscillating star. As all the magnetic chemically peculiar objects, it presents CNO underabundance and overabundance of iron peak elements of ?100 times and of rare earths up to 4 dex with respect to the Sun. The determination was based on the conversion of the observed equivalent widths into abundances simultaneously to the determination of effective temperature and gravity. Since the Balmer lines of early type stars are very sensitive to the surface gravity while the flux distribution is sensitive to the effective temperature, I have adopted an iterative procedure to match the H{sub ?} line profile and the observed UV-Vis-NIR magnitudes of HD94660 looking for a consistency between the metallicity of the atmosphere model and the derived abundances. From my spectroscopic analysis, this star belongs to the no-rapid oscillating class.

  1. Metaproteomics reveals abundant transposase expression in mutualistic endosymbionts

    SciTech Connect (OSTI)

    Kleiner, Manuel; Young, Jacque C; Shah, Manesh B; Verberkmoes, Nathan C; Dubilier, Nicole

    2013-01-01

    Transposases, enzymes that catalyze the movement of mobile genetic elements, are the most abundant genes in nature. While many bacteria encode an abundance of transposases in their genomes, the current paradigm is that transposase gene expression is tightly regulated and generally low due to its severe mutagenic effects. In the current study, we detected the highest number of transposase proteins ever reported in bacteria, in symbionts of the gutless marine worm Olavius algarvensis using metaproteomics. At least 26 different transposases from 12 different families were detected and genomic and proteomic analyses suggest many of these are active. This high expression of transposases indicates that the mechanisms for their tight regulation have been disabled or destroyed. Based on recent studies on other symbionts and pathogens that showed high transposase transcription, we speculate that abundant transposase expression might be common in symbionts and pathogens.

  2. IceVeto: Extended PeV neutrino astronomy in the Southern Hemisphere with IceCube

    SciTech Connect (OSTI)

    Auffenberg, Jan; Collaboration: IceCube Collaboration

    2014-11-18

    IceCube, the world's largest high-energy neutrino observatory, built at the South Pole, recently reported evidence of an astrophysical neutrino flux extending to PeV energies in the Southern Hemisphere. This observation raises the question of how the sensitivity in this energy range could be further increased. In the down-going sector, in IceCube's case the Southern Hemisphere, backgrounds from atmospheric muons and neutrinos pose a challenge to the identification of an astrophysical neutrino flux. The IceCube analysis, that led to the evidence for astrophysical neutrinos, is based on an in-ice veto strategy for background rejection. One possibility available to IceCube is the concept of an extended surface detector, IceVeto, which could allow the rejection of a large fraction of atmospheric backgrounds, primarily for muons from cosmic ray (CR) air showers as well as from neutrinos in the same air showers. Building on the experience of IceTop/IceCube, possibly the most cost-effective and sensitive way to build IceVeto is as an extension of the IceTop detector, with simple photomultiplier based detector modules for CR air shower detection. Initial simulations and estimates indicate that such a veto detector will significantly increase the sensitivity to an astrophysical flux of ?{sub ?} induced muon tracks in the Southern Hemisphere compared to current analyses. Here we present the motivation and capabilities based on initial simulations. Conceptual ideas for a simplified surface array will be discussed briefly.

  3. ChemCam data abundant at Planetary Conference

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    ChemCam data abundant at Planetary Conference ChemCam data abundant at Planetary Conference Members of the Mars Science Laboratory Curiosity rover ChemCam team will present more than two dozen posters and talks during the 44th Lunar and Planetary Science Conference. March 15, 2013 This image shows the ChemCam mast unit mounted on the Curiosity rover as it is being prepared in the clean room prior to the launch of NASA's Mars Science Laboratory mission. ChemCam fires a powerful laser that can

  4. HYDROGEN-DEUTERIUM EXCHANGE IN PHOTOLYZED METHANE-WATER ICES

    SciTech Connect (OSTI)

    Weber, Amanda S.; Hodyss, Robert; Johnson, Paul V.; Willacy, Karen; Kanik, Isik

    2009-09-20

    Previous work has concluded that H-D exchange occurs readily in polycyclic aromatic hydrocarbons frozen in deuterated water (D{sub 2}O) irradiated with ultraviolet light. Here, we examine H-D exchange in methane-water ices following exposure to ultraviolet radiation and analyze the products formed as a result. We find that H-D exchange also occurs in methane-water ices by means of ultraviolet photolysis. Exchange proceeds through a radical mechanism that implies that almost all organic species will undergo significant H-D exchange with the matrix in water ices exposed to ultraviolet radiation. Given sufficient energetic processing of the ice, the H/D ratio of an ice matrix may be transferred to the organic species in the ice.

  5. NuTeV Anomaly Helps Shed Light on Physics of the Nucleus | Jefferson Lab

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    NuTeV Anomaly Helps Shed Light on Physics of the Nucleus NEWPORT NEWS, VA, June 29, 2009 - A new calculation clarifies the complicated relationship between protons and neutrons in the atomic nucleus and offers a fascinating resolution of the famous NuTeV Anomaly. The calculation, published in the journal Physical Review Letters on June 26, was carried out by a collaboration of researchers from the Department of Energy's Thomas Jefferson National Accelerator Facility, Tokai University and the

  6. Spin differences in the Zr 90 compound nucleus induced by ( p , p ' ) , (

    Office of Scientific and Technical Information (OSTI)

    p , d ) , and ( p , t ) surrogate reactions (Journal Article) | SciTech Connect Spin differences in the Zr 90 compound nucleus induced by ( p , p ' ) , ( p , d ) , and ( p , t ) surrogate reactions Citation Details In-Document Search This content will become publicly available on November 3, 2016 Title: Spin differences in the Zr 90 compound nucleus induced by ( p , p ' ) , ( p , d ) , and ( p , t ) surrogate reactions Authors: Ota, S. ; Burke, J. T. ; Casperson, R. J. ; Escher, J. E. ;

  7. Hydrogen Material Compatibility for Hydrogen ICE | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Material Compatibility for Hydrogen ICE Hydrogen Material Compatibility for Hydrogen ICE 2009 DOE Hydrogen Program and Vehicle Technologies Program Annual Merit Review and Peer Evaluation Meeting, May 18-22, 2009 -- Washington D.C. PDF icon pm_04_smith.pdf More Documents & Publications Hydrogen Materials Compatibility for the H-ICE Engine Friction Reduction Through Surface Finish and Coatings Low-Friction Hard Coatings

  8. Ice Sheet Model Reveals Most Comprehensive Projections for West

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Antarctica's Future Most Comprehensive Projections for West Antarctica's Future Revealed Ice Sheet Model Reveals Most Comprehensive Projections for West Antarctica's Future BISICLES Simulations Run at NERSC Help Estimate Ice Loss, Sea Level Rise August 18, 2015 Contact: Linda Vu, +1 510 495 2402, lvu@lbl.gov IceSheet Retreat in the Amundsen Sea Embayment in 2154 (Credit: Cornford et al., The Cryosphere, 2015) A new international study is the first to use a high-resolution, large-scale

  9. Magnetic charge crystals imaged in artificial spin ice

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Magnetic charge crystals imaged in artificial spin ice Magnetic charge crystals imaged in artificial spin ice Potential data storage and computational advances could follow August 27, 2013 Potential data storage and computational advances could follow A 3-D depiction of the honeycomb artificial spin ice topography after the annealing and cooling protocols. The light and dark colors represent the north and south magnetic poles of the islands. Image by Ian Gilbert, U. of I. Department of Physics

  10. ARM - Lesson Plans: When Floating Ice Melts in the Sea

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    When Floating Ice Melts in the Sea Outreach Home Room News Publications Traditional Knowledge Kiosks Barrow, Alaska Tropical Western Pacific Site Tours Contacts Students Study Hall About ARM Global Warming FAQ Just for Fun Meet our Friends Cool Sites Teachers Teachers' Toolbox Lesson Plans Lesson Plans: When Floating Ice Melts in the Sea Objective The objective is to investigate the effect on sea level due to the melting of floating ice due to global warming. Materials Each student or group of

  11. Initial results from ensemble SCM simulations of TWP-ICE

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    9 Status of the TWP Status of the TWP Status of the TWP - - - ICE SCM ICE SCM ICE SCM intercomparison intercomparison intercomparison Laura Davies, Christian Jakob Monash University, Australia Thanks to Kenneth Cheung and Marty Singh March 2009 Outline * Forcing method * Upper level temperature biases? The whys and wherefores.... * Initial single column model results * Future directions * GCSS intercomparison project March 2009 Forcing methods Forcing methods Forcing methods March 2009 Forcing

  12. STATEMENT OF WORK (SOW) TEMPLATE FOR ICE SUPPORT CONTRACTOR

    Energy Savers [EERE]

    ICE SUPPORT CONTRACTOR The template presented below is a Statement of Work (SOW) for services of an ICE Support Contractor for assisting OECM in conducting an ICE. Project and review specific information should be incorporated. Explanatory text appears in italics, while information that should be selected appears in <<brackets>>. The format and contents of this SOW is not compulsory, and the use is at the discretion of the OECM Analysts, tailored as appropriate for the desired

  13. Nanotextured Anti-Icing Surfaces | GE Global Research

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Demonstrate Promising Anti-icing Nano Surfaces Click to email this to a friend (Opens in new window) Share on Facebook (Opens in new window) Click to share (Opens in new window) Click to share on LinkedIn (Opens in new window) Click to share on Tumblr (Opens in new window) GE Scientists Demonstrate Promising Anti-icing Nano Surfaces GE Global Research today presented new research findings on its nanotextured anti-icing surfaces. In addition to dramatically reducing ice adhesion, these surfaces

  14. Single Particle Database of Natural Ice Crystals: Dimensions

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Particle Database of Natural Ice Crystals: Dimensions and Aspect Ratios For original submission and image(s), see ARM Research Highlights http:www.arm.govsciencehighlights...

  15. optimal initial conditions for coupling ice sheet models to earth...

    Office of Scientific and Technical Information (OSTI)

    optimal initial conditions for coupling ice sheet models to earth system models Perego, Mauro Sandia National Laboratories Sandia National Laboratories; Price, Stephen F. Dr...

  16. The TWP-ICE CRM Intercomparison Specification and First Results

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    all elevations ice is a net sink for water vapor above the melting layer net hydration by hydrometeors occurs primarily below 5 km water vapor lifted by convection...

  17. IceCube: A Cubic Kilometer Radiation Detector

    SciTech Connect (OSTI)

    IceCube Collaboration; Klein, Spencer R; Klein, S.R.

    2008-06-01

    IceCube is a 1 km{sup 3} neutrino detector now being built at the Amudsen-Scott South Pole Station. It consists of 4800 Digital Optical Modules (DOMs) which detect Cherenkov radiation from the charged particles produced in neutrino interactions. IceCube will observe astrophysical neutrinos with energies above about 100 GeV. IceCube will be able to separate {nu}{sub {mu}}, {nu}{sub t}, and {nu}{sub {tau}} interactions because of their different topologies. IceCube construction is currently 50% complete.

  18. Covered Product Category: Air-Cooled Ice Machines

    Broader source: Energy.gov [DOE]

    The Federal Energy Management Program (FEMP) provides acquisition guidance for air-cooled ice machines, which are covered by the ENERGY STAR program.

  19. Rapid development of an ice sheet climate application using the...

    Office of Scientific and Technical Information (OSTI)

    Citation Details In-Document Search Title: Rapid development of an ice sheet climate ... Country of Publication: United States Language: English Word Cloud More Like This Full ...

  20. Reducing uncertainty in high-resolution sea ice models.

    SciTech Connect (OSTI)

    Peterson, Kara J.; Bochev, Pavel Blagoveston

    2013-07-01

    Arctic sea ice is an important component of the global climate system, reflecting a significant amount of solar radiation, insulating the ocean from the atmosphere and influencing ocean circulation by modifying the salinity of the upper ocean. The thickness and extent of Arctic sea ice have shown a significant decline in recent decades with implications for global climate as well as regional geopolitics. Increasing interest in exploration as well as climate feedback effects make predictive mathematical modeling of sea ice a task of tremendous practical import. Satellite data obtained over the last few decades have provided a wealth of information on sea ice motion and deformation. The data clearly show that ice deformation is focused along narrow linear features and this type of deformation is not well-represented in existing models. To improve sea ice dynamics we have incorporated an anisotropic rheology into the Los Alamos National Laboratory global sea ice model, CICE. Sensitivity analyses were performed using the Design Analysis Kit for Optimization and Terascale Applications (DAKOTA) to determine the impact of material parameters on sea ice response functions. Two material strength parameters that exhibited the most significant impact on responses were further analyzed to evaluate their influence on quantitative comparisons between model output and data. The sensitivity analysis along with ten year model runs indicate that while the anisotropic rheology provides some benefit in velocity predictions, additional improvements are required to make this material model a viable alternative for global sea ice simulations.

  1. The Rush to Exploit an Increasingly Ice-Free Arctic

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Rush to Exploit an Increasingly Ice-Free Arctic - Sandia Energy Energy Search Icon Sandia Home Locations Contact Us Employee Locator Energy & Climate Secure & Sustainable Energy ...

  2. Modeling the Effect of Ice Nuclei on ARM Clouds

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Upper-Tropospheric Ice Water Content in TWP-ICE Xiping Zeng, Wei-Kuo Tao, Minghua Zhang, and Shaochen Xie March 31, 2009 Papers Published Recently * Zeng, X., W.-K. Tao, M. Zhang, A. Y. Hou, S. Xie, S. Lang, X. Li, D. Starr, X. Li, and J. Simpson, 2009: An indirect effect of ice nuclei on atmospheric radiation. J. Atmos. Sci., 66, 41-61. * Zeng, X., W.-K. Tao, M. Zhang, A. Y. Hou, S. Xie, S. Lang, X. Li, D. Starr, and X. Li, 2009: A contribution by ice nuclei to global warming. Quart. J. Roy.

  3. The role of ice nuclei recycling in the maintenance of cloud ice in Arctic mixed-phase stratocumulus

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Solomon, A.; Feingold, G.; Shupe, M. D.

    2015-04-21

    This study investigates the maintenance of cloud ice production in Arctic mixed phase stratocumulus in large-eddy simulations that include a prognostic ice nuclei (IN) formulation and a diurnal cycle. Balances derived from a mixed-layer model and phase analyses are used to provide insight into buffering mechanisms that maintain ice in these cloud systems. We find that for the case under investigation, IN recycling through subcloud sublimation considerably prolongs ice production over a multi-day integration. This effective source of IN to the cloud dominates over mixing sources from above or below the cloud-driven mixed layer. Competing feedbacks between dynamical mixing andmore » recycling are found to slow the rate of ice lost from the mixed layer when a diurnal cycle is simulated. The results of this study have important implications for maintaining phase partitioning of cloud ice and liquid that determine the radiative forcing of Arctic mixed-phase clouds.« less

  4. The role of ice nuclei recycling in the maintenance of cloud ice in Arctic mixed-phase stratocumulus

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Solomon, A.; Feingold, G.; Shupe, M. D.

    2015-09-25

    This study investigates the maintenance of cloud ice production in Arctic mixed-phase stratocumulus in large eddy simulations that include a prognostic ice nuclei (IN) formulation and a diurnal cycle. Balances derived from a mixed-layer model and phase analyses are used to provide insight into buffering mechanisms that maintain ice in these cloud systems. We find that, for the case under investigation, IN recycling through subcloud sublimation considerably prolongs ice production over a multi-day integration. This effective source of IN to the cloud dominates over mixing sources from above or below the cloud-driven mixed layer. Competing feedbacks between dynamical mixing andmore » recycling are found to slow the rate of ice lost from the mixed layer when a diurnal cycle is simulated. The results of this study have important implications for maintaining phase partitioning of cloud ice and liquid that determine the radiative forcing of Arctic mixed-phase clouds.« less

  5. Flight Path 30R | ICE II

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    R The shape of the neutron spectrum here is very similar to that of neutrons produced in the atmosphere by cosmic rays but with a neutron flux a million times higher, depending on altitude. This large flux allows testing of semiconductor devices at greatly accelerated rates. Target 4 Flight Path 30R (ICE II) Target 4 Flight Path 30R (4FP30R) utilizes the neutrons that scatter off the tungsten spallation source at approximately 30 degrees to beam right. The experiments utilizing this flight path

  6. An update on land-ice modeling in the CESM (Conference) | SciTech...

    Office of Scientific and Technical Information (OSTI)

    The current model, however, has significant limitations: The land-ice coupling is one-way; ... of Glimmer-CISM with the shallow-ice approximation; and there is no ice-ocean coupling. ...

  7. Passive ice freezing-releasing heat pipe. [Patent application

    DOE Patents [OSTI]

    Gorski, A.J.; Schertz, W.W.

    1980-09-29

    A heat pipe device has been developed which permits completely passive ice formation and periodic release of ice without requiring the ambient temperature to rise above the melting point of water. This passive design enables the maximum amount of cooling capacity to be stored in the tank.

  8. Third international workshop on ice storage for cooling applications

    SciTech Connect (OSTI)

    Gorski, A.J.

    1986-04-01

    The third international workshop on ice storage for cooling applications which was informal and interactive in nature, was open to persons interested in all ice-growing technologies and in ice storage, both seasonal and diurnal. Presentations were made on some 20 topics, ranging from freezers in Alaska to ice cooling of commercial jet aircraft. Workshop tours included visits to ice-storage systems at Commonwealth Edison's facilities in Bolingbrook and Des Plaines Valley, the A.C. Neilsen builing in Northbrook, and the new State of Illinois Center in Chicago. The first workshop in the present series considered the future of ice storage and predicted applications in the agricultural sector, desalinization, and commercial ice production. Progress has been rapid in the intervening two years, and an important topic at the third workshop was the possible use of ''warm ices'' (clathrate hydrates) for energy storage. This report consists primarily of abstracts of presentations made at the workshop. Persons wishing to obtain further information about particular papers should contact the speakers directly; speakers' addresses and telephone numbers are listed in this report.

  9. An update on land-ice modeling in the CESM (Conference) | SciTech Connect

    Office of Scientific and Technical Information (OSTI)

    An update on land-ice modeling in the CESM Citation Details In-Document Search Title: An update on land-ice modeling in the CESM Mass loss from land ice, including the Greenland and Antarctic ice sheets as well as smaller glacier and ice caps, is making a large and growing contribution to global sea-level rise. Land ice is only beginning to be incorporated in climate models. The goal of the Land Ice Working Group (LIWG) is to develop improved land-ice models and incorporate them in CESM, in

  10. [?/Fe]ABUNDANCES OF FOUR OUTER M31 HALO STARS

    SciTech Connect (OSTI)

    Vargas, Luis C.; Geha, Marla; Tollerud, Erik J. [Department of Astronomy, Yale University, 260 Whitney Avenue, New Haven, CT 06511 (United States); Gilbert, Karoline M. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Kirby, Evan N. [California Institute of Technology, 1200 East California Boulevard, MC 249-17, Pasadena, CA 91125 (United States); Guhathakurta, Puragra, E-mail: luis.vargas@yale.edu [UCO/Lick Observatory and Department of Astronomy and Astrophysics, University of California, 1156 High Street, Santa Cruz, CA 95064 (United States)

    2014-12-10

    We present alpha element to iron abundance ratios, [?/Fe], for four stars in the outer stellar halo of the Andromeda Galaxy (M31). The stars were identified as high-likelihood field halo stars by Gilbert et al. and lie at projected distances between 70 and 140 kpc from M31's center. These are the first alpha abundances measured for a halo star in a galaxy beyond the Milky Way. The stars range in metallicity between [Fe/H] = 2.2 and [Fe/H] = 1.4. The sample's average [?/Fe] ratio is +0.20 0.20. The best-fit average value is elevated above solar, which is consistent with rapid chemical enrichment from Type II supernovae. The mean [?/Fe] ratio of our M31 outer halo sample agrees (within the uncertainties) with that of Milky Way inner/outer halo stars that have a comparable range of [Fe/H].

  11. Ice Nucleation of Fungal Spores from the Classes Agaricomycetes, Ustilaginomycetes, and Eurotiomycetes, and the effect on the Atmospheric Transport of these Spores

    SciTech Connect (OSTI)

    Haga, D. I.; Burrows, Susannah M.; Iannone, R.; Wheeler, M. J.; Mason, R.; Chen, J.; Polishchuk, E. A.; Poschl, U.; Bertram, Allan K.

    2014-08-26

    Ice nucleation on fungal spores may affect the frequency and properties of ice and mixed-phase clouds. We studied the ice nucleation properties of 12 different species of fungal spores chosen from three classes: Agaricomycetes, Ustilagomycetes, and Eurotiomycetes. Agaricomycetes include many types of mushroom species and are cosmopolitan all over the globe. Ustilagomycetes are agricultural pathogens and have caused widespread damage to crops. Eurotiomycetes are found on all types of decaying material and include important human allergens. We focused on these classes since they are thought to be abundant in the atmosphere and because there is very little information on the ice nucleation ability of these classes of spores in the literature. All of the fungal spores investigated were found to cause freezing of water droplets at temperatures warmer than homogeneous freezing. The cumulative number of ice nuclei per spore was 0.001 at temperatures between -19 C and -29 C, 0.01 between -25.5 C and -31 C, and 0.1 between -26 C and -36 C. On average, the order of ice nucleating ability for these spores is Ustilagomycetes > Agaricomycetes ? Eurotiomycetes. We show that at temperatures below -20 C, all of the fungal spores studied here are less efficient ice nuclei compared to Asian mineral dust on a per surface area basis. We used our new freezing results together with data in the literature to compare the freezing temperatures of spores from the phyla Basidiomycota and Ascomycota, which together make up 98 % of known fungal species found on Earth. The data show that within both phyla (Ascomycota and Basidiomycota) there is a wide range of freezing properties, and also that the variation within a phylum is greater than the variation between the average freezing properties of the phyla. Using a global chemistry-climate transport model, we investigated whether ice nucleation on the studied spores, followed by precipitation, can influence the atmospheric transport and global distributions of these spores in the atmosphere. Simulations show that inclusion of ice nucleation scavenging of fungal spores in mixed-phase clouds can decrease the surface annual mean mixing ratios of fungal spores over the oceans and polar regions and decrease annual mean mixing ratios in the upper troposphere.

  12. Harvesting Energy from Abundant, Low Quality Sources of Heat - Energy

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Innovation Portal Solar Thermal Solar Thermal Industrial Technologies Industrial Technologies Advanced Materials Advanced Materials Find More Like This Return to Search Harvesting Energy from Abundant, Low Quality Sources of Heat Lawrence Livermore National Laboratory Contact LLNL About This Technology Technology Marketing SummaryThe basic concept of energy harvesting is to collect energy from solar or other free sources of thermal energy that exist in the environment and convert them to

  13. Methods and apparatus for rotor blade ice detection

    DOE Patents [OSTI]

    LeMieux, David Lawrence

    2006-08-08

    A method for detecting ice on a wind turbine having a rotor and one or more rotor blades each having blade roots includes monitoring meteorological conditions relating to icing conditions and monitoring one or more physical characteristics of the wind turbine in operation that vary in accordance with at least one of the mass of the one or more rotor blades or a mass imbalance between the rotor blades. The method also includes using the one or more monitored physical characteristics to determine whether a blade mass anomaly exists, determining whether the monitored meteorological conditions are consistent with blade icing; and signaling an icing-related blade mass anomaly when a blade mass anomaly is determined to exist and the monitored meteorological conditions are determined to be consistent with icing.

  14. THE PHASES OF WATER ICE IN THE SOLAR NEBULA

    SciTech Connect (OSTI)

    Ciesla, Fred J.

    2014-03-20

    Understanding the phases of water ice that were present in the solar nebula has implications for understanding cometary and planetary compositions as well as the internal evolution of these bodies. Here we show that amorphous ice formed more readily than previously recognized, with formation at temperatures <70K being possible under protoplanetary disk conditions. We further argue that photodesorption and freeze-out of water molecules near the surface layers of the solar nebula would have provided the conditions needed for amorphous ice to form. This processing would be a natural consequence of ice dynamics and would allow for the trapping of noble gases and other volatiles in water ice in the outer solar nebula.

  15. Field demonstration of the ICE 250{trademark} Cleaning System

    SciTech Connect (OSTI)

    Johnston, J.L.; Jackson, L.M.

    1999-10-05

    The ICE 250{trademark} Cleaning System was engineered to convert water into small ice particles for use in cleaning and decontamination applications. Ice crystals are produced in a special icemaker and pressured through a hose-nozzle onto the surface to be cleaned. The Rocky Mountain Oilfield Testing Center and Ice Cleaning Systems, Inc., conducted a test of this system at Naval Petroleum Reserve No. 3 to evaluate the system's cleaning capabilities in an oil field environment. Equipment cleaned included an oil storage tank, a rod pumping unit, a road grader, and a wellhead. Contaminants were unrefined sour crude oil, hydraulic fluid, paraffin, and dirt, occurring separately and as mixtures. In all four demonstration cleaning tasks, the ICE 250 System effectively removed surface contaminant mixtures in a timely manner and left no oily residue. A minimal amount of waste moisture was generated, thereby reducing cleanup and disposal costs.

  16. THE NUCLEUS OF MAIN-BELT COMET 259P/GARRADD

    SciTech Connect (OSTI)

    MacLennan, Eric M.; Hsieh, Henry H. E-mail: emaclenn@utk.edu

    2012-10-10

    We present observations of the main-belt comet 259P/Garradd, previously known as P/2008 R1 (Garradd), obtained in 2011 and 2012 using the Gemini North Telescope on Mauna Kea in Hawaii and the SOAR telescope at Cerro Pachon in Chile, with the goal of computing the object's phase function and nucleus size. We find an absolute magnitude of H{sub R} = 19.71 {+-} 0.05 mag and slope parameter of G{sub R} = -0.08 {+-} 0.05 for the inactive nucleus, corresponding to an effective nucleus radius of r{sub e} = 0.30 {+-} 0.02 km, assuming an R-band albedo of p{sub R} = 0.05. We also revisit observations reported for 259P while it was active in 2008 to quantify the dust mass loss and compare the object with other known main-belt comets.

  17. Publisher's Note: High-spin lifetime measurements in the N=Z nucleus {sup

    Office of Scientific and Technical Information (OSTI)

    72}Kr [Phys. Rev. C 75, 041301(R) (2007)] (Journal Article) | SciTech Connect Publisher's Note: High-spin lifetime measurements in the N=Z nucleus {sup 72}Kr [Phys. Rev. C 75, 041301(R) (2007)] Citation Details In-Document Search Title: Publisher's Note: High-spin lifetime measurements in the N=Z nucleus {sup 72}Kr [Phys. Rev. C 75, 041301(R) (2007)] No abstract prepared. Authors: Andreoiu, C. ; Svensson, C. E. ; Afanasjev, A. V. ; Austin, R. A. E. ; Carpenter, M. P. ; Dashdorj, D. ; Finlay,

  18. Erratum: Coulomb excitation of the proton-dripline nucleus {sup 20}Na

    Office of Scientific and Technical Information (OSTI)

    [Phys. Rev. C 80, 044325 (2009)] (Journal Article) | SciTech Connect Erratum: Coulomb excitation of the proton-dripline nucleus {sup 20}Na [Phys. Rev. C 80, 044325 (2009)] Citation Details In-Document Search Title: Erratum: Coulomb excitation of the proton-dripline nucleus {sup 20}Na [Phys. Rev. C 80, 044325 (2009)] No abstract prepared. Authors: Schumaker, M. A. ; Cline, D. ; Hackman, G. ; Pearson, C. J. ; Svensson, C. E. ; Wu, C. Y. ; Andreyev, A. ; Austin, R. A. E. ; Ball, G. C. ;

  19. Air conditioning system with supplemental ice storing and cooling capacity

    DOE Patents [OSTI]

    Weng, Kuo-Lianq; Weng, Kuo-Liang

    1998-01-01

    The present air conditioning system with ice storing and cooling capacity can generate and store ice in its pipe assembly or in an ice storage tank particularly equipped for the system, depending on the type of the air conditioning system. The system is characterized in particular in that ice can be produced and stored in the air conditioning system whereby the time of supplying cooled air can be effectively extended with the merit that the operation cycle of the on and off of the compressor can be prolonged, extending the operation lifespan of the compressor in one aspect. In another aspect, ice production and storage in great amount can be performed in an off-peak period of the electrical power consumption and the stored ice can be utilized in the peak period of the power consumption so as to provide supplemental cooling capacity for the compressor of the air conditioning system whereby the shift of peak and off-peak power consumption can be effected with ease. The present air conditioning system can lower the installation expense for an ice-storing air conditioning system and can also be applied to an old conventional air conditioning system.

  20. Standard big bang nucleosynthesis and primordial CNO abundances after Planck

    SciTech Connect (OSTI)

    Coc, Alain [Centre de Sciences Nuclaires et de Sciences de la Matire (CSNSM), CNRS/IN2P3, Universit Paris Sud 11, UMR 8609, Btiment 104, F91405 Orsay Campus (France); Uzan, Jean-Philippe; Vangioni, Elisabeth, E-mail: coc@csnsm.in2p3.fr, E-mail: uzan@iap.fr, E-mail: vangioni@iap.fr [Institut d'Astrophysique de Paris, UMR-7095 du CNRS, Universit Pierre et Marie Curie, 98 bis bd Arago, 75014 Paris (France)

    2014-10-01

    Primordial or big bang nucleosynthesis (BBN) is one of the three historical strong evidences for the big bang model. The recent results by the Planck satellite mission have slightly changed the estimate of the baryonic density compared to the previous WMAP analysis. This article updates the BBN predictions for the light elements using the cosmological parameters determined by Planck, as well as an improvement of the nuclear network and new spectroscopic observations. There is a slight lowering of the primordial Li/H abundance, however, this lithium value still remains typically 3 times larger than its observed spectroscopic abundance in halo stars of the Galaxy. According to the importance of this ''lithium problem{sup ,} we trace the small changes in its BBN calculated abundance following updates of the baryonic density, neutron lifetime and networks. In addition, for the first time, we provide confidence limits for the production of {sup 6}Li, {sup 9}Be, {sup 11}B and CNO, resulting from our extensive Monte Carlo calculation with our extended network. A specific focus is cast on CNO primordial production. Considering uncertainties on the nuclear rates around the CNO formation, we obtain CNO/H?(5-30)10{sup -15}. We further improve this estimate by analyzing correlations between yields and reaction rates and identified new influential reaction rates. These uncertain rates, if simultaneously varied could lead to a significant increase of CNO production: CNO/H?10{sup -13}. This result is important for the study of population III star formation during the dark ages.

  1. DIVERSITY OF TYPE Ia SUPERNOVAE IMPRINTED IN CHEMICAL ABUNDANCES

    SciTech Connect (OSTI)

    Tsujimoto, Takuji [National Astronomical Observatory of Japan, Mitaka-shi, Tokyo 181-8588 (Japan); Shigeyama, Toshikazu, E-mail: taku.tsujimoto@nao.ac.jp [Research Center for the Early Universe, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan)

    2012-12-01

    A time delay of Type Ia supernova (SN Ia) explosions hinders the imprint of their nucleosynthesis on stellar abundances. However, some occasional cases give birth to stars that avoid enrichment of their chemical compositions by massive stars and thereby exhibit an SN-Ia-like elemental feature including a very low [Mg/Fe] ( Almost-Equal-To - 1). We highlight the elemental feature of Fe-group elements for two low-Mg/Fe objects detected in nearby galaxies, and propose the presence of a class of SNe Ia that yield the low abundance ratios of [Cr, Mn, Ni/Fe]. Our novel models of chemical evolution reveal that our proposed class of SNe Ia (slow SNe Ia) is associated with ones exploding on a long timescale after their stellar birth and give a significant impact on the chemical enrichment in the Large Magellanic Cloud (LMC). In the Galaxy, on the other hand, this effect is unseen due to the overwhelming enrichment by the major class of SNe Ia that explode promptly (prompt SNe Ia) and eject a large amount of Fe-group elements. This nicely explains the different [Cr, Mn, Ni/Fe] features between the two galaxies as well as the puzzling feature seen in the LMC stars exhibiting very low Ca but normal Mg abundances. Furthermore, the corresponding channel of slow SN Ia is exemplified by performing detailed nucleosynthesis calculations in the scheme of SNe Ia resulting from a 0.8 + 0.6 M{sub Sun} white dwarf merger.

  2. Platinum-group element abundance patterns in different mantle environments

    SciTech Connect (OSTI)

    Rehkaemper, M.; Halliday, A.N.; Barfod, D.; Fitton, J.G.; Dawson, J.B.

    1997-11-28

    Mantle-derived xenoliths from the Cameroon Line and northern Tanzania display differences in their platinum-group element (PGE) abundance patterns. The Cameroon Line lherzolites have uniform PGE patterns indicating a homogeneous upper mantle over several hundreds of kilometers, with approximately chondritic PGE ratios. The PGE patterns of the Tanzanian peridotites are similar to the PGE systematics of ultramafic rocks from ophiolites. The differences can be explained if the northern Tanzanian lithosphere developed in a fluid-rich suprasubduction zone environment, whereas the Cameroon Line lithosphere only experienced melt extraction from anhydrous periodotites. 32 refs., 2 figs., 1 tab.

  3. Searching for Cosmic Accelerators via IceCube

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Searching for Cosmic Accelerators via IceCube Searching for Cosmic Accelerators via IceCube Berkeley Lab Researchers Part of an International Hunt November 21, 2013 Lynn Yarris, lcyarris@lbl.gov, 510.486.5375 Bert.jpg This event display shows "Bert," one of two neutrino events discovered at IceCube whose energies exceeded one petaelectronvolt (PeV). The colors show when the light arrived, with reds being the earliest, succeeded by yellows, greens and blues. The size of the circle

  4. ARM - Publications: Science Team Meeting Documents: Investigation of Ice

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Crystal Shapes Using Multi-resolution Techniques Investigation of Ice Crystal Shapes Using Multi-resolution Techniques McFarquhar, Greg University of Illinois Better knowledge of small-scale features from ice crystals are needed to determine their effects on radiation and hence to improve the treatment of clouds in climate models. With the Cloud Particle Imager (CPI) it is now possible to capture ice crystal images with 2.3 μm resolution and 256 gray scales of illumination, providing an

  5. Development, sensitivity analysis, and uncertainty quantification of high-fidelity arctic sea ice models.

    SciTech Connect (OSTI)

    Peterson, Kara J.; Bochev, Pavel Blagoveston; Paskaleva, Biliana S.

    2010-09-01

    Arctic sea ice is an important component of the global climate system and due to feedback effects the Arctic ice cover is changing rapidly. Predictive mathematical models are of paramount importance for accurate estimates of the future ice trajectory. However, the sea ice components of Global Climate Models (GCMs) vary significantly in their prediction of the future state of Arctic sea ice and have generally underestimated the rate of decline in minimum sea ice extent seen over the past thirty years. One of the contributing factors to this variability is the sensitivity of the sea ice to model physical parameters. A new sea ice model that has the potential to improve sea ice predictions incorporates an anisotropic elastic-decohesive rheology and dynamics solved using the material-point method (MPM), which combines Lagrangian particles for advection with a background grid for gradient computations. We evaluate the variability of the Los Alamos National Laboratory CICE code and the MPM sea ice code for a single year simulation of the Arctic basin using consistent ocean and atmospheric forcing. Sensitivities of ice volume, ice area, ice extent, root mean square (RMS) ice speed, central Arctic ice thickness, and central Arctic ice speed with respect to ten different dynamic and thermodynamic parameters are evaluated both individually and in combination using the Design Analysis Kit for Optimization and Terascale Applications (DAKOTA). We find similar responses for the two codes and some interesting seasonal variability in the strength of the parameters on the solution.

  6. Microphysical Consequences of the Spatial Distribution of Ice Nucleation in Mixed-Phase Stratiform Clouds

    SciTech Connect (OSTI)

    Yang, Fan; Ovchinnikov, Mikhail; Shaw, Raymond A.

    2014-07-28

    Mixed-phase stratiform clouds can persist even with steady ice precipitation fluxes, and the origin and microphysical properties of the ice crystals are of interest. Vapor deposition growth and sedimentation of ice particles along with a uniform volume source of ice nucleation, leads to a power law relation between ice water content wi and ice number concentration ni with exponent 2.5. The result is independent of assumptions about the vertical velocity structure of the cloud and is therefore more general than the related expression of Yang et al. [2013]. The sensitivity of the wi-ni relationship to the spatial distribution of ice nucleation is confirmed by Lagrangian tracking and ice growth with cloud-volume, cloud-top, and cloud-base sources of ice particles through a time-dependent cloud field. Based on observed wi and ni from ISDAC, a lower bound of 0.006 m^3/s is obtained for the ice crystal formation rate.

  7. Minimalist Model of Ice Microphysics in Mixed-phase Stratiform Clouds

    SciTech Connect (OSTI)

    Yang, F.; Ovchinnikov, Mikhail; Shaw, Raymond A.

    2013-07-28

    The question of whether persistent ice crystal precipitation from super cooled layer clouds can be explained by time-dependent, stochastic ice nucleation is explored using an approximate, analytical model, and a large-eddy simulation (LES) cloud model. The updraft velocity in the cloud defines an accumulation zone, where small ice particles cannot fall out until they are large enough, which will increase the residence time of ice particles in the cloud. Ice particles reach a quasi-steady state between growth by vapor deposition and fall speed at cloud base. The analytical model predicts that ice water content (wi) has a 2.5 power law relationship with ice number concentration ni. wi and ni from a LES cloud model with stochastic ice nucleation also confirm the 2.5 power law relationship. The prefactor of the power law is proportional to the ice nucleation rate, and therefore provides a quantitative link to observations of ice microphysical properties.

  8. Ice Concentration Retrieval in Stratiform Mixed-phase Clouds Using Cloud Radar Reflectivity Measurements and 1D Ice Growth Model Simulations

    SciTech Connect (OSTI)

    Zhang, Damao; Wang, Zhien; Heymsfield, Andrew J.; Fan, Jiwen; Luo, Tao

    2014-10-01

    Measurement of ice number concentration in clouds is important but still challenging. Stratiform mixed-phase clouds (SMCs) provide a simple scenario for retrieving ice number concentration from remote sensing measurements. The simple ice generation and growth pattern in SMCs offers opportunities to use cloud radar reflectivity (Ze) measurements and other cloud properties to infer ice number concentration quantitatively. To understand the strong temperature dependency of ice habit and growth rate quantitatively, we develop a 1-D ice growth model to calculate the ice diffusional growth along its falling trajectory in SMCs. The radar reflectivity and fall velocity profiles of ice crystals calculated from the 1-D ice growth model are evaluated with the Atmospheric Radiation Measurements (ARM) Climate Research Facility (ACRF) ground-based high vertical resolution radar measurements. Combining Ze measurements and 1-D ice growth model simulations, we develop a method to retrieve the ice number concentrations in SMCs at given cloud top temperature (CTT) and liquid water path (LWP). The retrieved ice concentrations in SMCs are evaluated with in situ measurements and with a three-dimensional cloud-resolving model simulation with a bin microphysical scheme. These comparisons show that the retrieved ice number concentrations are within an uncertainty of a factor of 2, statistically.

  9. Nanotextured Anti-Icing Surfaces | GE Global Research

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Demonstrate Promising Anti-icing Nano Surfaces Click to email this to a friend (Opens in new window) Share on Facebook (Opens in new window) Click to share (Opens in new window)...

  10. Sandia's ice sheet modeling of Greenland, Antarctica helps predict...

    National Nuclear Security Administration (NNSA)

    The Greenland and Antarctic ice sheets will make a dominant contribution to 21st century sea-level rise if current climate trends continue. However, predicting the expected loss of ...

  11. Progress on a TWP-ICE Monsoon Case Study

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Outline Introduction 25-mb large-scale forcing 10-mb large-scale forcing Tracers Future work Progress on a TWP-ICE Monsoon Case Study Ann Fridlind and Andrew Ackerman * NASA GISS...

  12. Magnetization plateaus of dipolar spin ice on kagome lattice

    SciTech Connect (OSTI)

    Xie, Y. L.; Wang, Y. L.; Yan, Z. B.; Liu, J.-M.

    2014-05-07

    Unlike spin ice on pyrochlore lattice, the spin ice structure on kagome lattice retains net magnetic charge, indicating non-negligible dipolar interaction in modulating the spin ice states. While it is predicted that the dipolar spin ice on kagome lattice exhibits a ground state with magnetic charge order and ?3???3 spin order, our work focuses on the magnetization plateau of this system. By employing the Wang-Landau algorithm, it is revealed that the lattice exhibits the fantastic three-step magnetization in response to magnetic field h along the [10] and [01] directions, respectively. For the h//[1 0] case, an additional ?3/6M{sub s} step, where M{sub s} is the saturated magnetization, is observed in a specific temperature range, corresponding to a new state with charge order and short-range spin order.

  13. ARM-UAV TWP-ICE Activities and Data

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    flown during the TWP-ICE experiment are presented. Data was also collected during the transit flight across the Pacific from Mojave California to Darwin Australia and on the...

  14. Ice Particle Projected Area- and Mass-dimension Expressions

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    m-D and A-D expressions in BMPs is described in this paper. Figure 1. The m-D expression (black curve) for synoptic ice clouds between -20C and -40C based on SCPP m-D...

  15. Arctic sea ice modeling with the material-point method.

    SciTech Connect (OSTI)

    Peterson, Kara J.; Bochev, Pavel Blagoveston

    2010-04-01

    Arctic sea ice plays an important role in global climate by reflecting solar radiation and insulating the ocean from the atmosphere. Due to feedback effects, the Arctic sea ice cover is changing rapidly. To accurately model this change, high-resolution calculations must incorporate: (1) annual cycle of growth and melt due to radiative forcing; (2) mechanical deformation due to surface winds, ocean currents and Coriolis forces; and (3) localized effects of leads and ridges. We have demonstrated a new mathematical algorithm for solving the sea ice governing equations using the material-point method with an elastic-decohesive constitutive model. An initial comparison with the LANL CICE code indicates that the ice edge is sharper using Materials-Point Method (MPM), but that many of the overall features are similar.

  16. Oil spreading in surface waters with an ice cover

    SciTech Connect (OSTI)

    Yapa, P.D.; Weerasuriya, S.A.; Belaskas, D.P.; Chowdhury, T.

    1993-02-01

    A study of oil spreading in surface waters in the presence of a floating ice cover is presented. The ice can be solid or fragmented. Both axi-symmetrical and uni-directional spreading are studied. The report describes the analytical and numerical model development, the experimental set-up, results from the laboratory experiments, and their comparison with the derived theory and the numerical simulation. To analyze the spreading of oil under solid ice, new equations are derived. These equations consider gravity (buoyancy) - inertia phase, gravity (buoyancy) - viscous phase, and the termination of spreading during the buoyancy - surface tension phase. The derivation considers both the constant discharge mode and the constant volume mode. Therefore, a complete description of the spreading phenomena from the time of initial spill to termination of spreading is presented. The emphasis of the study is on the dominant spreading mechanism for oil under ice, which is the buoyancy-viscous phase.

  17. Operating Experience Level 3, Winter Preparedness: Slips on Ice

    Broader source: Energy.gov [DOE]

    OE-3 2015-06: This Operating Experience Level 3 (OE-3) document provides information about the hazards of slips, trips, and falls on ice across the Department of Energy (DOE) Complex.

  18. A New Approach for Representing Ice Particles in Weather

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    mass mixing ratio, qi, c) cloud water mass mixing ratio, qc, d) rain mass mixing ratio, qr, e) rime mass fraction, Fr, f) mass-weighted mean ice particle density, p, g)...

  19. Covered Product Category: Water-Cooled Ice Machines | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Ice Machines Covered Product Category: Water-Cooled Ice Machines The Federal Energy Management Program (FEMP) provides acquisition guidance and federal efficiency requirements for water-cooled ice machines. Federal laws and requirements mandate that agencies meet these efficiency requirements in all procurement and acquisition actions that are not specifically exempted by law. Meeting Efficiency Requirements for Water-Cooled Ice Machines Federal agencies must purchase water-cooled ice machines

  20. Complex systems influence melting of Greenland ice sheet

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Complex systems influence melting of Greenland ice sheet Complex systems influence melting of Greenland ice sheet International research team's field work shows that, well, things are more complicated than we thought December 22, 2014 The newly discovered rolling movement shown in (A) three-dimensional cryo-electron microscopy image of ribosome, and (B) computer-generated atomic-resolution model of the human ribosome consistent with microscopy. An international team of researchers deployed to

  1. Insider features Barton's ice boat | The Ames Laboratory

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Insider features Barton's ice boat Former Director Tom Barton had the cover story in Insider 25 years ago featuring his ice boat. In honor of Valentine's Day, the issue also carried an article, "Chemistry That Works" featuring couples who worked at the Lab. There was also a story on intreped peddlers who biked to work throughout the winter. To see the entire issue, click on the cover

  2. IceCube: An Instrument for Neutrino Astronomy

    SciTech Connect (OSTI)

    IceCube Collaboration; Halzen, F.; Klein, S.

    2010-06-04

    Neutrino astronomy beyond the Sun was first imagined in the late 1950s; by the 1970s, it was realized that kilometer-scale neutrino detectors were required. The first such instrument, IceCube, is near completion and taking data. The IceCube project transforms a cubic kilometer of deep and ultra-transparent Antarctic ice into a particle detector. A total of 5,160 optical sensors are embedded into a gigaton of Antarctic ice to detect the Cherenkov light emitted by secondary particles produced when neutrinos interact with nuclei in the ice. Each optical sensor is a complete data acquisition system, including a phototube, digitization electronics, control and trigger systems and LEDs for calibration. The light patterns reveal the type (flavor) of neutrino interaction and the energy and direction of the neutrino, making neutrino astronomy possible. The scientific missions of IceCube include such varied tasks as the search for sources of cosmic rays, the observation of Galactic supernova explosions, the search for dark matter, and the study of the neutrinos themselves. These reach energies well beyond those produced with accelerator beams.

  3. Impact of individual nuclear masses on r-process abundances

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Mumpower, M. R.; Surman, R.; Fang, D. -L.; Beard, M.; Möller, P.; Kawano, T.; Aprahamian, A.

    2015-09-15

    We have performed for the first time a comprehensive study of the sensitivity of r-process nucleosynthesis to individual nuclear masses across the chart of nuclides. Using the latest version (2012) of the Finite-Range Droplet Model, we consider mass variations of ±0.5 MeV and propagate each mass change to all affected quantities, including Q values, reaction rates, and branching ratios. We find such mass variations can result in up to an order of magnitude local change in the final abundance pattern produced in an r-process simulation. As a result, we identify key nuclei whose masses have a substantial impact on abundancemore » predictions for hot, cold, and neutron star merger r-process scenarios and could be measured at future radioactive beam facilities.« less

  4. ICE MINERALOGY ACROSS AND INTO THE SURFACES OF PLUTO, TRITON, AND ERIS

    SciTech Connect (OSTI)

    Tegler, S. C.; Grundy, W. M.; Olkin, C. B.; Young, L. A.; Romanishin, W.; Cornelison, D. M.; Khodadadkouchaki, R. E-mail: W.Grundy@lowell.edu E-mail: layoung@boulder.swri.edu E-mail: DavidCornelison@MissouriState.edu

    2012-05-20

    We present three near-infrared spectra of Pluto taken with the Infrared Telescope Facility and SpeX, an optical spectrum of Triton taken with the MMT and the Red Channel Spectrograph, and previously published spectra of Pluto, Triton, and Eris. We combine these observations with a two-phase Hapke model and gain insight into the ice mineralogy on Pluto, Triton, and Eris. Specifically, we measure the methane-nitrogen mixing ratio across and into the surfaces of these icy dwarf planets. In addition, we present a laboratory experiment that demonstrates it is essential to model methane bands in spectra of icy dwarf planets with two methane phases-one highly diluted by nitrogen and the other rich in methane. For Pluto, we find bulk, hemisphere-averaged, methane abundances of 9.1% {+-} 0.5%, 7.1% {+-} 0.4%, and 8.2% {+-} 0.3% for sub-Earth longitudes of 10 Degree-Sign , 125 Degree-Sign , and 257 Degree-Sign . Application of the Wilcoxon rank sum test to our measurements finds these small differences are statistically significant. For Triton, we find bulk, hemisphere-averaged, methane abundances of 5.0% {+-} 0.1% and 5.3% {+-} 0.4% for sub-Earth longitudes of 138 Degree-Sign and 314 Degree-Sign . Application of the Wilcoxon rank sum test to our measurements finds the differences are not statistically significant. For Eris, we find a bulk, hemisphere-averaged, methane abundance of 10% {+-} 2%. Pluto, Triton, and Eris do not exhibit a trend in methane-nitrogen mixing ratio with depth into their surfaces over the few centimeter range probed by these observations. This result is contrary to the expectation that since visible light penetrates deeper into a nitrogen-rich surface than the depths from which thermal emission emerges, net radiative heating at depth would drive preferential sublimation of nitrogen leading to an increase in the methane abundance with depth.

  5. Understanding cirrus ice crystal number variability for different heterogeneous ice nucleation spectra

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Sullivan, S. C.; Morales Betancourt, R.; Barahona, D.; Nenes, A.

    2015-08-11

    Along with minimizing parameter uncertainty, understanding the cause of temporal and spatial variability of nucleated ice crystal number, Ni, is key to improving the representation of cirrus clouds in climate models. To this end, sensitivities of Ni to input variables like aerosol number and diameter provide valuable information about nucleation regime and efficiency for a given model formulation. Here we use the adjoint model of the Barahona and Nenes cirrus formation parameterization to understand Ni variability for various ice-nucleating particle (INP) spectra. Inputs are generated with the Community Atmosphere Model version 5, and simulations are done with a theoretically-derived spectrum,morea lab-based empirical spectrum, and two field-based empirical spectra that differ in the nucleation threshold for black carbon aerosol and in the active site density for dust. The magnitude and sign of Ni sensitivity to insoluble aerosol number can be directly linked to nucleation regime and efficiency of various INP. The lab-based spectrum calculates much higher INP efficiencies than field-based ones, which reveals a disparity in aerosol surface properties. Ni sensitivity to temperature tends to be low, due to the compensating effects of temperature on INP spectrum parameters; this low temperature sensitivity regime has been experimentally reported before but never unraveled as done here.less

  6. Neutron and weak-charge distributions of the 48Ca nucleus

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Hagen, Gaute; Forssen, Christian; Nazarewicz, Witold; Papenbrock, Thomas F.; Bacca, S.; Barnea, Nir; Carlsson, Boris; Drischler, Christian; Hebeler, Kai; Hjorth-Jensen, M.; et al

    2015-11-02

    What is the size of the atomic nucleus? This deceivably simple question is difficult to answer. Although the electric charge distributions in atomic nuclei were measured accurately already half a century ago, our knowledge of the distribution of neutrons is still deficient. In addition to constraining the size of atomic nuclei, the neutron distribution also impacts the number of nuclei that can exist and the size of neutron stars. We present an ab initio calculation of the neutron distribution of the neutron-rich nucleus 48Ca. We show that the neutron skin (difference between the radii of the neutron and proton distributions)more » is significantly smaller than previously thought. We also make predictions for the electric dipole polarizability and the weak form factor; both quantities that are at present targeted by precision measurements. Here, based on ab initio results for 48Ca, we provide a constraint on the size of a neutron star.« less

  7. A three-body model of the {sup 11}B nucleus

    SciTech Connect (OSTI)

    Dubovichenko, S. B.

    2011-08-15

    The binding energy and the rms charge and mass radii have been calculated in terms of the single-channel three-body {sup 4}He{sup 4}He{sup 3}H model of the {sup 11}B nucleus with an expansion of the three-body wave function in a nonorthogonal Gaussian basis. Parameters of the wave function are presented and convergence of the three-body energy depending on the number of expansion terms is demonstrated.

  8. What Is the Size of the Atomic Nucleus? | U.S. DOE Office of Science (SC)

    Office of Science (SC) Website

    Highlights » 2016 » What Is the Size of the Atomic Nucleus? Advanced Scientific Computing Research (ASCR) ASCR Home About Research Facilities Science Highlights Benefits of ASCR Funding Opportunities Advanced Scientific Computing Advisory Committee (ASCAC) Community Resources Contact Information Advanced Scientific Computing Research U.S. Department of Energy SC-21/Germantown Building 1000 Independence Ave., SW Washington, DC 20585 P: (301) 903-7486 F: (301) 903-4846 E: Email Us More

  9. EVOLUTION OF SNOW LINE IN OPTICALLY THICK PROTOPLANETARY DISKS: EFFECTS OF WATER ICE OPACITY AND DUST GRAIN SIZE

    SciTech Connect (OSTI)

    Oka, Akinori; Nakamoto, Taishi; Ida, Shigeru, E-mail: akinorioka1@gmail.com, E-mail: nakamoto@geo.titech.ac.jp [Department of Earth and Planetary Sciences, Tokyo Institute of Technology, Tokyo (Japan)

    2011-09-10

    Evolution of a snow line in an optically thick protoplanetary disk is investigated with numerical simulations. The ice-condensing region in the disk is obtained by calculating the temperature and the density with the 1+1D approach. The snow line migrates as the mass accretion rate ( M-dot ) in the disk decreases with time. Calculations are carried out from an early phase with high disk accretion rates ( M-dot {approx}10{sup -7} M{sub sun} yr{sup -1}) to a later phase with low disk accretion rates ( M-dot {approx}10{sup -12} M{sub sun} yr{sup -1}) using the same numerical method. It is found that the snow line moves inward for M-dot {approx}>10{sup -10} M{sub sun} yr{sup -1}, while it gradually moves outward in the later evolution phase with M-dot {approx}<10{sup -10} M{sub sun} yr{sup -1}. In addition to the silicate opacity, the ice opacity is taken into consideration. In the inward migration phase, the additional ice opacity increases the distance of the snow line from the central star by a factor of 1.3 for dust grains {approx}< 10 {mu}m in size and of 1.6 for {approx}> 100 {mu}m. It is inevitable that the snow line comes inside Earth's orbit in the course of the disk evolution if the viscosity parameter {alpha} is in the range 0.001-0.1, the dust-to-gas mass ratio is higher than a tenth of the solar abundance value, and the dust grains are smaller than 1 mm. The formation of water-devoid planetesimals in the terrestrial planet region seems to be difficult throughout the disk evolution, which imposes a new challenge to planet formation theory.

  10. Challenges of deflecting an asteroid or comet nucleus with a nuclear burst

    SciTech Connect (OSTI)

    Bradley, Paul A; Plesko, Cathy S; Clement, Ryan R. C.; Conlon, Le Ann M; Weaver, Robert P; Guzik, Joyce A; Pritchett - Sheets, Lori A; Huebner, Walter F

    2009-01-01

    There are many natural disasters that humanity has to deal with over time. These include earthquakes, tsunamis, hurricanes, floods, asteroid strikes, and so on. Some of these disasters occur slowly enough that some advance warning is possible for affected areas. In this case, the response is to evacuate the affected area and deal wilh the damage later. The Katrina and Rita hurricane evacuations on the U.S. Gulf Coasl in 2005 demonstrated the chaos that can result from such a response. In contrast with other natural disasters, it is likely that an asteroid or comet nucleus on a collision course with Earth will be detected with enough warning time to possibly deflect it away. Thanks to Near-Earth Object (NED) surveys, people are working towards a goal of cataloging at least 90% of all near-Earth objects with diameters larger than {approx} 140 meters in the next fifteen years. The important question then, is how to mitigate the threat from an asteroid or comet nucleus found to be on a collision course with Earth. In this paper. we briefly review some possible deflection methods, describe their good and bad points, and then embark on a more detailed description of using nuclear munitions in a standoff mode to deflect the asteroid or comet nucleus before it can hit Earth.

  11. STELLAR ELEMENTAL ABUNDANCE PATTERNS: IMPLICATIONS FOR PLANET FORMATION

    SciTech Connect (OSTI)

    Chambers, J. E.

    2010-11-20

    The solar photosphere is depleted in refractory elements compared to most solar twins, with the degree of depletion increasing with an element's condensation temperature. Here, I show that adding 4 Earth masses of Earth-like and carbonaceous-chondrite-like material to the solar convection zone brings the Sun's composition into line with the mean value for the solar twins. The observed solar composition could have arisen if the Sun's convection zone accreted material from the solar nebula that was depleted in refractory elements due to the formation of the terrestrial planets and ejection of rocky protoplanets from the asteroid belt. Most solar analogs are missing 0-10 Earth masses of rocky material compared to the most refractory-rich stars, providing an upper limit to the mass of rocky terrestrial planets that they possess. The missing mass is correlated with stellar metallicity. This suggests that the efficiency of planetesimal formation increases with stellar metallicity. Stars with and without known giant planets show a similar distribution of abundance trends. If refractory depletion is a signature of the presence of terrestrial planets, this suggests that there is not a strong correlation between the presence of terrestrial and giant planets in the same system.

  12. LARGE ABUNDANCES OF POLYCYCLIC AROMATIC HYDROCARBONS IN TITAN'S UPPER ATMOSPHERE

    SciTech Connect (OSTI)

    Lopez-Puertas, M.; Funke, B.; Garcia-Comas, M.; Dinelli, B. M.; Adriani, A.; D'Aversa, E.; Moriconi, M. L.; Boersma, C.; Allamandola, L. J.

    2013-06-20

    In this paper, we analyze the strong unidentified emission near 3.28 {mu}m in Titan's upper daytime atmosphere recently discovered by Dinelli et al. We have studied it by using the NASA Ames PAH IR Spectroscopic Database. The polycyclic aromatic hydrocarbons (PAHs), after absorbing UV solar radiation, are able to emit strongly near 3.3 {mu}m. By using current models for the redistribution of the absorbed UV energy, we have explained the observed spectral feature and have derived the vertical distribution of PAH abundances in Titan's upper atmosphere. PAHs have been found to be present in large concentrations, about (2-3) Multiplication-Sign 10{sup 4} particles cm{sup -3}. The identified PAHs have 9-96 carbons, with a concentration-weighted average of 34 carbons. The mean mass is {approx}430 u; the mean area is about 0.53 nm{sup 2}; they are formed by 10-11 rings on average, and about one-third of them contain nitrogen atoms. Recently, benzene together with light aromatic species as well as small concentrations of heavy positive and negative ions have been detected in Titan's upper atmosphere. We suggest that the large concentrations of PAHs found here are the neutral counterpart of those positive and negative ions, which hence supports the theory that the origin of Titan main haze layer is located in the upper atmosphere.

  13. ESTIMATION OF THE NEON/OXYGEN ABUNDANCE RATIO AT THE HELIOSPHERIC TERMINATION SHOCK AND IN THE LOCAL INTERSTELLAR MEDIUM FROM IBEX OBSERVATIONS

    SciTech Connect (OSTI)

    Bochsler, P.; Petersen, L.; Moebius, E.; Schwadron, N. A.; Wurz, P.; Scheer, J. A.; Fuselier, S. A.; McComas, D. J.; Bzowski, M.; Frisch, P. C.

    2012-02-01

    We report the first direct measurement of the Ne/O abundance ratio of the interstellar neutral gas flowing into the inner heliosphere. From the first year of Interstellar Boundary Explorer IBEX data collected in spring 2009, we derive the fluxes of interstellar neutral oxygen and neon. Using the flux ratio at the location of IBEX at 1 AU at the time of the observations, and using the ionization rates of neon and oxygen prevailing in the heliosphere during the period of solar minimum, we estimate the neon/oxygen ratios at the heliospheric termination shock and in the gas phase of the inflowing local interstellar medium. Our estimate is (Ne/O){sub gas,ISM} = 0.27 {+-} 0.10, which is-within the large given uncertainties-consistent with earlier measurements from pickup ions. Our value is larger than the solar abundance ratio, possibly indicating that a significant fraction of oxygen in the local interstellar medium is hidden in grains and/or ices.

  14. Effects of Pre-Existing Ice Crystals on Cirrus Clouds and Comparison between Different Ice Nucleation Parameterizations with the Community Atmosphere Model (CAM5)

    SciTech Connect (OSTI)

    Shi, Xiangjun; Liu, Xiaohong; Zhang, Kai

    2015-01-01

    In order to improve the treatment of ice nucleation in a more realistic manner in the Community Atmospheric Model version 5.3 (CAM5.3), the effects of preexisting ice crystals on ice nucleation in cirrus clouds are considered. In addition, by considering the in-cloud variability in ice saturation ratio, homogeneous nucleation takes place spatially only in a portion of cirrus cloud rather than in the whole area of cirrus cloud. With these improvements, the two unphysical limiters used in the representation of ice nucleation are removed. Compared to observations, the ice number concentrations and the probability distributions of ice number concentration are both improved with the updated treatment. The preexisting ice crystals significantly reduce ice number concentrations in cirrus clouds, especially at mid- to high latitudes in the upper troposphere (by a factor of ~10). Furthermore, the contribution of heterogeneous ice nucleation to cirrus ice crystal number increases considerably.Besides the default ice nucleation parameterization of Liu and Penner (2005, hereafter LP) in CAM5.3, two other ice nucleation parameterizations of Barahona and Nenes (2009, hereafter BN) and Krcher et al. (2006, hereafter KL) are implemented in CAM5.3 for the comparison. In-cloud ice crystal number concentration, percentage contribution from heterogeneous ice nucleation to total ice crystal number, and preexisting ice effects simulated by the three ice nucleation parameterizations have similar patterns in the simulations with present-day aerosol emissions. However, the change (present-day minus pre-industrial times) in global annual mean column ice number concentration from the KL parameterization (3.24106 m-2) is obviously less than that from the LP (8.46106 m-2) and BN (5.62106 m-2) parameterizations. As a result, experiment using the KL parameterization predicts a much smaller anthropogenic aerosol longwave indirect forcing (0.24 W m-2) than that using the LP (0.46 W m-2) and BN (0.39 W m-2) parameterizations.

  15. The sticking of atomic hydrogen on amorphous water ice

    SciTech Connect (OSTI)

    Veeraghattam, Vijay K.; Manrodt, Katie; Lewis, Steven P.; Stancil, P. C. E-mail: lewis@physast.uga.edu

    2014-07-20

    Using classical molecular dynamics, we have simulated the sticking and scattering process of a hydrogen atom on an amorphous ice film to predict the sticking probability of hydrogen on ice surfaces. A wide range of initial kinetic energies of the incident hydrogen atom (10 K-600 K) and two different ice temperatures (10 K and 70 K) were used to investigate this fundamental process in interstellar chemistry. We report here the sticking probability of atomic hydrogen as a function of incident kinetic energy, gas temperature, and substrate temperature, which can be used in astrophysical models. The current results are compared to previous theoretical and experimental studies that have reported a wide range in the sticking coefficient.

  16. THE CORONAL ABUNDANCES OF MID-F DWARFS

    SciTech Connect (OSTI)

    Wood, Brian E.; Laming, J. Martin [Naval Research Laboratory, Space Science Division, Washington, DC 20375 (United States)

    2013-05-10

    A Chandra spectrum of the moderately active nearby F6 V star {pi}{sup 3} Ori is used to study the coronal properties of mid-F dwarfs. We find that {pi}{sup 3} Ori's coronal emission measure distribution is very similar to those of moderately active G and K dwarfs, with an emission measure peak near log T = 6.6 seeming to be ubiquitous for such stars. In contrast to coronal temperature, coronal abundances are known to depend on spectral type for main sequence stars. Based on this previously known relation, we expected {pi}{sup 3} Ori's corona to exhibit an extremely strong ''first ionization potential (FIP) effect'', a phenomenon first identified on the Sun where elements with low FIP are enhanced in the corona. We instead find that {pi}{sup 3} Ori's corona exhibits a FIP effect essentially identical to that of the Sun and other early G dwarfs, perhaps indicating that the increase in FIP bias toward earlier spectral types stops or at least slows for F stars. We find that {pi}{sup 3} Ori's coronal characteristics are significantly different from two previously studied mid-F stars, Procyon (F5 IV-V) and {tau} Boo (F7 V). We believe {pi}{sup 3} Ori is more representative of the coronal characteristics of mid-F dwarfs, with Procyon being different because of luminosity class, and {tau} Boo being different because of the effects of one of two close companions, one stellar ({tau} Boo B: M2 V) and one planetary.

  17. Development and Applications of the Community Ice Sheet Model (Conference)

    Office of Scientific and Technical Information (OSTI)

    | SciTech Connect and Applications of the Community Ice Sheet Model Citation Details In-Document Search Title: Development and Applications of the Community Ice Sheet Model × You are accessing a document from the Department of Energy's (DOE) SciTech Connect. This site is a product of DOE's Office of Scientific and Technical Information (OSTI) and is provided as a public service. Visit OSTI to utilize additional information resources in energy science and technology. A paper copy of this

  18. Ice plug employed on subsea pipeline bend during repair

    SciTech Connect (OSTI)

    1997-12-22

    The first controlled-temperature ice plug in the bend of an offshore gas trunkline has been carried out for Phillips Petroleum Co. Norway on its Norpipe A.S. platform in the German sector of the North Sea. The procedure was part of a subsea valve repair operation. The ice plug was successfully formed offshore and tested to a differential pressure of 1,450 psi. Repair of two valves required only 5 days during which time gas production was operating at close to 50--60% via the platform bypass, says the service company. The paper discusses the procedure.

  19. Time-resolved x-ray diffraction across water-ices VI/VII transformatio...

    Office of Scientific and Technical Information (OSTI)

    diffraction across water-ices VIVII transformations using dynamic-DAC Citation Details In-Document Search Title: Time-resolved x-ray diffraction across water-ices VIVII ...

  20. Predicting Land-Ice Retreat and Sea-Level Rise with the Community...

    Office of Scientific and Technical Information (OSTI)

    Coastal stakeholders need defensible predictions of 21st century sea-level rise (SLR). ... To assess the likelihood of fast retreat of marine ice sheets, we need coupled ice-sheet...

  1. Land-ice modeling for sea-level prediction (Technical Report...

    Office of Scientific and Technical Information (OSTI)

    Technical Report: Land-ice modeling for sea-level prediction Citation Details In-Document Search Title: Land-ice modeling for sea-level prediction Authors: Lipscomb, William H 1 ...

  2. Predicting Land-Ice Retreat and Sea-Level Rise with the Community...

    Office of Scientific and Technical Information (OSTI)

    from the marine-based West Antarctic Ice Sheet, linked to changes in Southern Ocean wind stress. To assess the likelihood of fast retreat of marine ice sheets, we need coupled...

  3. Ice at the Interface: Atmosphere-Ice-Ocean Boundary Layer Processes and Their Role in Polar Change---Workshop Report

    SciTech Connect (OSTI)

    Hunke, Elizabeth C.

    2012-07-23

    The atmosphere-ocean boundary layer in which sea ice resides includes many complex processes that require a more realistic treatment in GCMs, particularly as models move toward full earth system descriptions. The primary purpose of the workshop was to define and discuss such coupled processes from observational and modeling points of view, including insight from both the Arctic and Antarctic systems. The workshop met each of its overarching goals, including fostering collaboration among experimentalists, theorists and modelers, proposing modeling strategies, and ascertaining data availability and needs. Several scientific themes emerged from the workshop, such as the importance of episodic or extreme events, precipitation, stratification above and below the ice, and the marginal ice zone, whose seasonal Arctic migrations now traverse more territory than in the past.

  4. The direct detection of boosted dark matter at high energies and PeV events at IceCube

    SciTech Connect (OSTI)

    Bhattacharya, A.; Gandhi, R.; Gupta, A.

    2015-03-13

    We study the possibility of detecting dark matter directly via a small but energetic component that is allowed within present-day constraints. Drawing closely upon the fact that neutral current neutrino nucleon interactions are indistinguishable from DM-nucleon interactions at low energies, we extend this feature to high energies for a small, non-thermal but highly energetic population of DM particle χ, created via the decay of a significantly more massive and long-lived non-thermal relic ϕ, which forms the bulk of DM. If χ interacts with nucleons, its cross-section, like the neutrino-nucleus coherent cross-section, can rise sharply with energy leading to deep inelastic scattering, similar to neutral current neutrino-nucleon interactions at high energies. Thus, its direct detection may be possible via cascades in very large neutrino detectors. As a specific example, we apply this notion to the recently reported three ultra-high energy PeV cascade events clustered around 1−2 PeV at IceCube (IC). We discuss the features which may help discriminate this scenario from one in which only astrophysical neutrinos constitute the event sample in detectors like IC.

  5. The direct detection of boosted dark matter at high energies and PeV events at IceCube

    SciTech Connect (OSTI)

    Bhattacharya, A.; Gandhi, R.; Gupta, A.

    2015-03-13

    We study the possibility of detecting dark matter directly via a small but energetic component that is allowed within present-day constraints. Drawing closely upon the fact that neutral current neutrino nucleon interactions are indistinguishable from DM-nucleon interactions at low energies, we extend this feature to high energies for a small, non-thermal but highly energetic population of DM particle ?, created via the decay of a significantly more massive and long-lived non-thermal relic ?, which forms the bulk of DM. If ? interacts with nucleons, its cross-section, like the neutrino-nucleus coherent cross-section, can rise sharply with energy leading to deep inelastic scattering, similar to neutral current neutrino-nucleon interactions at high energies. Thus, its direct detection may be possible via cascades in very large neutrino detectors. As a specific example, we apply this notion to the recently reported three ultra-high energy PeV cascade events clustered around 1 2 PeV at IceCube (IC). We discuss the features which may help discriminate this scenario from one in which only astrophysical neutrinos constitute the event sample in detectors like IC.

  6. The direct detection of boosted dark matter at high energies and PeV events at IceCube

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Bhattacharya, A.; Gandhi, R.; Gupta, A.

    2015-03-13

    We study the possibility of detecting dark matter directly via a small but energetic component that is allowed within present-day constraints. Drawing closely upon the fact that neutral current neutrino nucleon interactions are indistinguishable from DM-nucleon interactions at low energies, we extend this feature to high energies for a small, non-thermal but highly energetic population of DM particle χ, created via the decay of a significantly more massive and long-lived non-thermal relic Φ, which forms the bulk of DM. If χ interacts with nucleons, its cross-section, like the neutrino-nucleus coherent cross-section, can rise sharply with energy leading to deep inelasticmore » scattering, similar to neutral current neutrino-nucleon interactions at high energies. Thus, its direct detection may be possible via cascades in very large neutrino detectors. As a specific example, we apply this notion to the recently reported three ultra-high energy PeV cascade events clustered around 1 – 2 PeV at IceCube (IC). We discuss the features which may help discriminate this scenario from one in which only astrophysical neutrinos constitute the event sample in detectors like IC.« less

  7. SOLAR MODELS WITH ACCRETION. I. APPLICATION TO THE SOLAR ABUNDANCE PROBLEM

    Office of Scientific and Technical Information (OSTI)

    (Journal Article) | SciTech Connect SOLAR MODELS WITH ACCRETION. I. APPLICATION TO THE SOLAR ABUNDANCE PROBLEM Citation Details In-Document Search Title: SOLAR MODELS WITH ACCRETION. I. APPLICATION TO THE SOLAR ABUNDANCE PROBLEM We generate new standard solar models using newly analyzed nuclear fusion cross sections and present results for helioseismic quantities and solar neutrino fluxes. The status of the solar abundance problem is discussed. We investigate whether nonstandard solar models

  8. City of Eagan …Civic Ice Arena Renovation | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    City of Eagan …Civic Ice Arena Renovation City of Eagan …Civic Ice Arena Renovation Project objectives: Provide a reliable central ice making and heating system that meets the performance requirements of the owner. Reduce operation and maintenance costs. PDF icon gshp_lutz_eagan_ice_arena.pdf More Documents & Publications GEOTHERMAL POWER GENERATION PLANT Wilders Grove Solid Waste Services Center Decision Analysis for EGS

  9. Ice formation on nitric acid coated dust particles: Laboratory and modeling studies

    SciTech Connect (OSTI)

    Kulkarni, Gourihar R.; Zhang, Kai; Zhao, Chun; Nandasiri, Manjula I.; Shutthanandan, V.; Liu, Xiaohong; Fast, Jerome D.; Berg, Larry K.

    2015-08-16

    Changes in the ice nucleation characteristics of atmospherically relevant mineral dust particles due to nitric acid coating are not well understood. Further, the atmospheric implications of dust coating on ice-cloud properties under different assumptions of primary ice nucleation mechanisms are unknown. We investigated ice nucleation ability of Arizona test dust, illite, K-feldspar and quartz as a function of temperature (-25 to -30C) and relative humidity with respect to water (75 to 110%). Particles were size selected at 250 nm and transported (bare or coated) to the ice nucleation chamber to determine the fraction of particles nucleating ice at various temperature and water saturation conditions. All dust nucleated ice at water-subsaturated conditions, but the coated particles showed a reduction in their ice nucleation ability compared to bare particles. However, at water-supersaturated conditions, we observed that bare and coated particles had nearly similar ice nucleation characteristics. X-ray diffraction patterns indicated that structural properties of bare dust particles modified after acid treatment. We found that lattice parameters were slightly different, but crystallite sizes of the coated particles were reduced compared to bare particles. Next, single-column model results show that simulated ice crystal number concentrations mostly depends upon fraction of particles that are coated, primary ice nucleation mechanisms, and the competition between ice nucleation mechanisms to nucleate ice. In general, we observed that coating modify the ice-cloud properties and the picture of ice and mixed-phase cloud evolution is complex when different primary ice nucleation mechanisms are competing for fixed water vapor mass.

  10. Purchasing Energy-Efficient Air-Cooled Ice Machines

    Broader source: Energy.gov [DOE]

    The Federal Energy Management Program (FEMP) provides acquisition guidance for air-cooled ice machines, a product category covered by ENERGY STAR efficiency requirements. Federal laws and requirements mandate that agencies purchase ENERGY STAR-qualified products or FEMP-designated products in all product categories covered by these programs and in any acquisition actions that are not specifically exempted by law.

  11. Ice method for production of hydrogen clathrate hydrates

    DOE Patents [OSTI]

    Lokshin, Konstantin (Santa Fe, NM); Zhao, Yusheng (Los Alamos, NM)

    2008-05-13

    The present invention includes a method for hydrogen clathrate hydrate synthesis. First, ice and hydrogen gas are supplied to a containment volume at a first temperature and a first pressure. Next, the containment volume is pressurized with hydrogen gas to a second higher pressure, where hydrogen clathrate hydrates are formed in the process.

  12. Calibration and Characterization of the IceCube Photomultiplier Tube

    SciTech Connect (OSTI)

    IceCube Collaboration; Abbasi, R.; al., et

    2010-02-11

    Over 5,000 PMTs are being deployed at the South Pole to compose the IceCube neutrino observatory. Many are placed deep in the ice to detect Cherenkov light emitted by the products of high-energy neutrino interactions, and others are frozen into tanks on the surface to detect particles from atmospheric cosmic ray showers. IceCube is using the 10-inch diameter R7081-02 made by Hamamatsu Photonics. This paper describes the laboratory characterization and calibration of these PMTs before deployment. PMTs were illuminated with pulses ranging from single photons to saturation level. Parameterizations are given for the single photoelectron charge spectrum and the saturation behavior. Time resolution, late pulses and afterpulses are characterized. Because the PMTs are relatively large, the cathode sensitivity uniformity was measured. The absolute photon detection efficiency was calibrated using Rayleigh-scattered photons from a nitrogen laser. Measured characteristics are discussed in the context of their relevance to IceCube event reconstruction and simulation efforts.

  13. Neutrino-nucleus scattering of {sup 95,97}Mo and {sup 116}Cd

    SciTech Connect (OSTI)

    Ydrefors, E.; Almosly, W.; Suhonen, J.

    2013-12-30

    Accurate knowledge about the nuclear responses to supernova neutrinos for relevant nuclear targets is important both for neutrino detection and for astrophysical applications. In this paper we discuss the cross sections for the charged-current neutrino-nucleus scatterings off {sup 95,97}Mo and {sup 116}Cd. The microscopic quasiparticle-phonon model is adopted for the odd-even nuclei {sup 95,97}Mo. In the case of {sup 116}Cd we present cross sections both for the Bonn one-boson-exchange potential and self-consistent calculations based on modern Skyrme interactions.

  14. Label-free three-dimensional imaging of cell nucleus using third-harmonic generation microscopy

    SciTech Connect (OSTI)

    Lin, Jian; Zheng, Wei; Wang, Zi; Huang, Zhiwei

    2014-09-08

    We report the implementation of the combined third-harmonic generation (THG) and two-photon excited fluorescence (TPEF) microscopy for label-free three-dimensional (3-D) imaging of cell nucleus morphological changes in liver tissue. THG imaging shows regular spherical shapes of normal hepatocytes nuclei with inner chromatin structures while revealing the condensation of chromatins and nuclear fragmentations in hepatocytes of diseased liver tissue. Colocalized THG and TPEF imaging provides complementary information of cell nuclei and cytoplasm in tissue. This work suggests that 3-D THG microscopy has the potential for quantitative analysis of nuclear morphology in cells at a submicron-resolution without the need for DNA staining.

  15. Investigating ice nucleation in cirrus clouds with an aerosol-enabled Multiscale Modeling Framework

    SciTech Connect (OSTI)

    Zhang, Chengzhu; Wang, Minghuai; Morrison, H.; Somerville, Richard C.; Zhang, Kai; Liu, Xiaohong; Li, J-L F.

    2014-11-06

    In this study, an aerosol-dependent ice nucleation scheme [Liu and Penner, 2005] has been implemented in an aerosol-enabled multi-scale modeling framework (PNNL MMF) to study ice formation in upper troposphere cirrus clouds through both homogeneous and heterogeneous nucleation. The MMF model represents cloud scale processes by embedding a cloud-resolving model (CRM) within each vertical column of a GCM grid. By explicitly linking ice nucleation to aerosol number concentration, CRM-scale temperature, relative humidity and vertical velocity, the new MMF model simulates the persistent high ice supersaturation and low ice number concentration (10 to 100/L) at cirrus temperatures. The low ice number is attributed to the dominance of heterogeneous nucleation in ice formation. The new model simulates the observed shift of the ice supersaturation PDF towards higher values at low temperatures following homogeneous nucleation threshold. The MMF models predict a higher frequency of midlatitude supersaturation in the Southern hemisphere and winter hemisphere, which is consistent with previous satellite and in-situ observations. It is shown that compared to a conventional GCM, the MMF is a more powerful model to emulate parameters that evolve over short time scales such as supersaturation. Sensitivity tests suggest that the simulated global distribution of ice clouds is sensitive to the ice nucleation schemes and the distribution of sulfate and dust aerosols. Simulations are also performed to test empirical parameters related to auto-conversion of ice crystals to snow. Results show that with a value of 250 ?m for the critical diameter, Dcs, that distinguishes ice crystals from snow, the model can produce good agreement to the satellite retrieved products in terms of cloud ice water path and ice water content, while the total ice water is not sensitive to the specification of Dcs value.

  16. Investigating ice nucleation in cirrus clouds with an aerosol-enabled Multiscale Modeling Framework

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Zhang, Chengzhu; Wang, Minghuai; Morrison, H.; Somerville, Richard C.; Zhang, Kai; Liu, Xiaohong; Li, J-L F.

    2014-11-06

    In this study, an aerosol-dependent ice nucleation scheme [Liu and Penner, 2005] has been implemented in an aerosol-enabled multi-scale modeling framework (PNNL MMF) to study ice formation in upper troposphere cirrus clouds through both homogeneous and heterogeneous nucleation. The MMF model represents cloud scale processes by embedding a cloud-resolving model (CRM) within each vertical column of a GCM grid. By explicitly linking ice nucleation to aerosol number concentration, CRM-scale temperature, relative humidity and vertical velocity, the new MMF model simulates the persistent high ice supersaturation and low ice number concentration (10 to 100/L) at cirrus temperatures. The low ice numbermore » is attributed to the dominance of heterogeneous nucleation in ice formation. The new model simulates the observed shift of the ice supersaturation PDF towards higher values at low temperatures following homogeneous nucleation threshold. The MMF models predict a higher frequency of midlatitude supersaturation in the Southern hemisphere and winter hemisphere, which is consistent with previous satellite and in-situ observations. It is shown that compared to a conventional GCM, the MMF is a more powerful model to emulate parameters that evolve over short time scales such as supersaturation. Sensitivity tests suggest that the simulated global distribution of ice clouds is sensitive to the ice nucleation schemes and the distribution of sulfate and dust aerosols. Simulations are also performed to test empirical parameters related to auto-conversion of ice crystals to snow. Results show that with a value of 250 μm for the critical diameter, Dcs, that distinguishes ice crystals from snow, the model can produce good agreement to the satellite retrieved products in terms of cloud ice water path and ice water content, while the total ice water is not sensitive to the specification of Dcs value.« less

  17. Investigating ice nucleation in cirrus clouds with an aerosol-enabled Multiscale Modeling Framework

    SciTech Connect (OSTI)

    Zhang, Chengzhu; Wang, Minghuai; Morrison, H.; Somerville, Richard C.; Zhang, Kai; Liu, Xiaohong; Li, J-L F.

    2014-12-01

    In this study, an aerosol-dependent ice nucleation scheme [Liu and Penner, 2005] has been implemented in an aerosol-enabled multi-scale modeling framework (PNNL MMF) to study ice formation in upper troposphere cirrus clouds through both homogeneous and heterogeneous nucleation. The MMF model represents cloud scale processes by embedding a cloud-resolving model (CRM) within each vertical column of a GCM grid. By explicitly linking ice nucleation to aerosol number concentration, CRM-scale temperature, relative humidity and vertical velocity, the new MMF model simulates the persistent high ice supersaturation and low ice number concentration (10 to 100/L) at cirrus temperatures. The low ice number is attributed to the dominance of heterogeneous nucleation in ice formation. The new model simulates the observed shift of the ice supersaturation PDF towards higher values at low temperatures following homogeneous nucleation threshold. The MMF models predict a higher frequency of midlatitude supersaturation in the Southern hemisphere and winter hemisphere, which is consistent with previous satellite and in-situ observations. It is shown that compared to a conventional GCM, the MMF is a more powerful model to emulate parameters that evolve over short time scales such as supersaturation. Sensitivity tests suggest that the simulated global distribution of ice clouds is sensitive to the ice nucleation schemes and the distribution of sulfate and dust aerosols. Simulations are also performed to test empirical parameters related to auto-conversion of ice crystals to snow. Results show that with a value of 250 ?m for the critical diameter, Dcs, that distinguishes ice crystals from snow, the model can produce good agreement to the satellite retrieved products in terms of cloud ice water path and ice water content, while the total ice water is not sensitive to the specification of Dcs value.

  18. On the scalability of the Albany/FELIX first-order Stokes approximation ice

    Office of Scientific and Technical Information (OSTI)

    sheet solver for large-scale simulations of the Greenland and Antarctic ice sheets (Journal Article) | SciTech Connect On the scalability of the Albany/FELIX first-order Stokes approximation ice sheet solver for large-scale simulations of the Greenland and Antarctic ice sheets Citation Details In-Document Search Title: On the scalability of the Albany/FELIX first-order Stokes approximation ice sheet solver for large-scale simulations of the Greenland and Antarctic ice sheets We examine the

  19. A marine biogenic source of atmospheric ice-nucleating particles (Journal

    Office of Scientific and Technical Information (OSTI)

    Article) | SciTech Connect A marine biogenic source of atmospheric ice-nucleating particles Citation Details In-Document Search Title: A marine biogenic source of atmospheric ice-nucleating particles The formation of ice in clouds is facilitated by the presence of airborne ice nucleating particles1,2. Sea spray is one of the major global sources of atmospheric particles, but it is unclear to what extent these particles are capable of nucleating ice3-11. Here we show that material in the sea

  20. ELECTRON IRRADIATION OF CARBON DISULFIDE-OXYGEN ICES: TOWARD THE FORMATION OF SULFUR-BEARING MOLECULES IN INTERSTELLAR ICES

    SciTech Connect (OSTI)

    Maity, Surajit; Kaiser, Ralf I. [Department of Chemistry, University of Hawai'i at Manoa, Honolulu, HI 96822 (United States)

    2013-08-20

    The formation of sulfur-bearing molecules in interstellar ices was investigated during the irradiation of carbon disulfide (CS{sub 2})-oxygen (O{sub 2}) ices with energetic electrons at 12 K. The irradiation-induced chemical processing of these ices was monitored online and in situ via Fourier transform infrared spectroscopy to probe the newly formed products quantitatively. The sulfur-bearing molecules produced during the irradiation were sulfur dioxide (SO{sub 2}), sulfur trioxide (SO{sub 3}), and carbonyl sulfide (OCS). Formations of carbon dioxide (CO{sub 2}), carbon monoxide (CO), and ozone (O{sub 3}) were observed as well. To fit the temporal evolution of the newly formed products and to elucidate the underlying reaction pathways, kinetic reaction schemes were developed and numerical sets of rate constants were derived. Our studies suggest that carbon disulfide (CS{sub 2}) can be easily transformed to carbonyl sulfide (OCS) via reactions with suprathermal atomic oxygen (O), which can be released from oxygen-containing precursors such as water (H{sub 2}O), carbon dioxide (CO{sub 2}), and/or methanol (CH{sub 3}OH) upon interaction with ionizing radiation. This investigation corroborates that carbonyl sulfide (OCS) and sulfur dioxide (SO{sub 2}) are the dominant sulfur-bearing molecules in interstellar ices.

  1. Raman scattering method and apparatus for measuring isotope ratios and isotopic abundances

    DOE Patents [OSTI]

    Harney, Robert C.; Bloom, Stewart D.

    1978-01-01

    Raman scattering is used to measure isotope ratios and/or isotopic abundances. A beam of quasi-monochromatic photons is directed onto the sample to be analyzed, and the resulting Raman-scattered photons are detected and counted for each isotopic species of interest. These photon counts are treated mathematically to yield the desired isotope ratios or isotopic abundances.

  2. Molecular interactions with ice: Molecular embedding, adsorption, detection, and release

    SciTech Connect (OSTI)

    Gibson, K. D.; Langlois, Grant G.; Li, Wenxin; Sibener, S. J.; Killelea, Daniel R.

    2014-11-14

    The interaction of atomic and molecular species with water and ice is of fundamental importance for chemistry. In a previous series of publications, we demonstrated that translational energy activates the embedding of Xe and Kr atoms in the near surface region of ice surfaces. In this paper, we show that inert molecular species may be absorbed in a similar fashion. We also revisit Xe embedding, and further probe the nature of the absorption into the selvedge. CF{sub 4} molecules with high translational energies (?3 eV) were observed to embed in amorphous solid water. Just as with Xe, the initial adsorption rate is strongly activated by translational energy, but the CF{sub 4} embedding probability is much less than for Xe. In addition, a larger molecule, SF{sub 6}, did not embed at the same translational energies that both CF{sub 4} and Xe embedded. The embedding rate for a given energy thus goes in the order Xe > CF{sub 4} > SF{sub 6}. We do not have as much data for Kr, but it appears to have a rate that is between that of Xe and CF{sub 4}. Tentatively, this order suggests that for Xe and CF{sub 4}, which have similar van der Waals radii, the momentum is the key factor in determining whether the incident atom or molecule can penetrate deeply enough below the surface to embed. The more massive SF{sub 6} molecule also has a larger van der Waals radius, which appears to prevent it from stably embedding in the selvedge. We also determined that the maximum depth of embedding is less than the equivalent of four layers of hexagonal ice, while some of the atoms just below the ice surface can escape before ice desorption begins. These results show that energetic ballistic embedding in ice is a general phenomenon, and represents a significant new channel by which incident species can be trapped under conditions where they would otherwise not be bound stably as surface adsorbates. These findings have implications for many fields including environmental science, trace gas collection and release, and the chemical composition of astrophysical icy bodies in space.

  3. Hydrogen Fuel Pilot Plant and Hydrogen ICE Vehicle Testing

    SciTech Connect (OSTI)

    J. Francfort

    2005-03-01

    The U.S. Department Energy's Advanced Vehicle Testing Activity (AVTA) teamed with Electric Transportation Applications (ETA) and Arizona Public Service (APS) to develop the APS Alternative Fuel (Hydrogen) Pilot Plant that produces and compresses hydrogen on site through an electrolysis process by operating a PEM fuel cell in reverse; natural gas is also compressed onsite. The Pilot Plant dispenses 100% hydrogen, 15 to 50% blends of hydrogen and compressed natural gas (H/CNG), and 100% CNG via a credit card billing system at pressures up to 5,000 psi. Thirty internal combustion engine (ICE) vehicles (including Daimler Chrysler, Ford and General Motors vehicles) are operating on 100% hydrogen and 15 to 50% H/CNG blends. Since the Pilot Plant started operating in June 2002, they hydrogen and H/CNG ICE vehicels have accumulated 250,000 test miles.

  4. American Indian Complex to Cool Off Using Ice Storage System

    Broader source: Energy.gov [DOE]

    In Oklahoma City, summer temperatures can get above 100 degrees, making cooling more of a necessity than a luxury. But the designers of the American Indian Cultural Center and Museum (AICCM) wanted to make cooling choices that reflect American Indian cultures' respect for the land. So, rather than using conventional air-conditioning, the museum's main complex will use an ice storage system estimated to save 644,000 kilowatt hours of electricity a year.

  5. NASA Award for Marginal Ice Zone Observations and Process Experiment

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    (MIZOPEX) Award for Marginal Ice Zone Observations and Process Experiment (MIZOPEX) - Sandia Energy Energy Search Icon Sandia Home Locations Contact Us Employee Locator Energy & Climate Secure & Sustainable Energy Future Stationary Power Energy Conversion Efficiency Solar Energy Wind Energy Water Power Supercritical CO2 Geothermal Natural Gas Safety, Security & Resilience of the Energy Infrastructure Energy Storage Nuclear Power & Engineering Grid Modernization Battery

  6. Sandia's ice sheet modeling of Greenland, Antarctica helps predict

    National Nuclear Security Administration (NNSA)

    sea-level rise | National Nuclear Security Administration ice sheet modeling of Greenland, Antarctica helps predict sea-level rise | National Nuclear Security Administration Facebook Twitter Youtube Flickr RSS People Mission Managing the Stockpile Preventing Proliferation Powering the Nuclear Navy Emergency Response Recapitalizing Our Infrastructure Countering Nuclear Terrorism About Our Programs Our History Who We Are Our Leadership Our Locations Budget Our Operations Library Bios

  7. Microsoft Word - 11_19_09 ice mkaer.doc

    Office of Environmental Management (EM)

    to: Department of Energy via email: expartecommunications@hq.doe.gov from: Debra Brunk date: November 20, 2009 subject: Exparte Communication This memo memorializes the meeting between AHAM and the Department of Energy on November 19, 2009 for inclusion in the public docket. The purpose of the meeting was to update the Department on the status of AHAM's development of an ice maker energy test procedure. The attendees are as follows: Ronald Lewis, Department of Energy Lucas Adin, Department of

  8. Microsoft Word - 11_4_09 ice maker.doc

    Office of Environmental Management (EM)

    gov from: Debra Brunk, Vice President Technical Services date: November 11, 2009 subject: Exparte Communication This memo memorializes the phone call between AHAM and the Department of Energy on November 4, 2009 for inclusion in the public docket. In summary, the issues discussed during the call were an update on including ice maker energy into the refrigerator-freezer test procedure and questions on the status regarding AHAM's clarification request on clothes washer drum volume determination.

  9. A man-made enhanced geothermal system (EGS) can extract the abundant heat resour

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    man-made enhanced geothermal system (EGS) can extract the abundant heat resource tens of thousands of feet below the surface and put it to good use. This would require: With an enhanced geothermal reservoir, you can generate power anywhere with hot rocks at depth! What makes EGS? + + Small pathways to conduct fluid through the hot rocks Fluid to carry heat from the rocks Abundant heat found in rocks at depth Abundant heat found in rocks at depth Limited pathways to conduct fluid Insufficient

  10. Black hole variability and the star formation-active galactic nucleus connection: Do all star-forming galaxies host an active galactic nucleus?

    SciTech Connect (OSTI)

    Hickox, Ryan C.; Chen, Chien-Ting J.; Civano, Francesca M.; Hainline, Kevin N.; Mullaney, James R.; Alexander, David M.; Goulding, Andy D.

    2014-02-10

    We investigate the effect of active galactic nucleus (AGN) variability on the observed connection between star formation and black hole accretion in extragalactic surveys. Recent studies have reported relatively weak correlations between observed AGN luminosities and the properties of AGN hosts, which has been interpreted to imply that there is no direct connection between AGN activity and star formation. However, AGNs may be expected to vary significantly on a wide range of timescales (from hours to Myr) that are far shorter than the typical timescale for star formation (?100 Myr). This variability can have important consequences for observed correlations. We present a simple model in which all star-forming galaxies host an AGN when averaged over ?100 Myr timescales, with long-term average AGN accretion rates that are perfectly correlated with the star formation rate (SFR). We show that reasonable prescriptions for AGN variability reproduce the observed weak correlations between SFR and L {sub AGN} in typical AGN host galaxies, as well as the general trends in the observed AGN luminosity functions, merger fractions, and measurements of the average AGN luminosity as a function of SFR. These results imply that there may be a tight connection between AGN activity and SFR over galaxy evolution timescales, and that the apparent similarities in rest-frame colors, merger rates, and clustering of AGNs compared to 'inactive' galaxies may be due primarily to AGN variability. The results provide motivation for future deep, wide extragalactic surveys that can measure the distribution of AGN accretion rates as a function of SFR.

  11. Decaying leptophilic dark matter at IceCube

    SciTech Connect (OSTI)

    Boucenna, Sofiane M.; Chianese, Marco; Mangano, Gianpiero; Miele, Gennaro; Morisi, Stefano; Pisanti, Ofelia; Vitagliano, Edoardo

    2015-12-29

    We present a novel interpretation of IceCube high energy neutrino events (with energy larger than 60 TeV) in terms of an extraterrestrial flux due to two different contributions: a flux originated by known astrophysical sources and dominating IceCube observations up to few hundreds TeV, and a new flux component where the most energetic neutrinos come from the leptophilic three-body decays of dark matter particles with a mass of few PeV. Differently from other approaches, we provide two examples of elementary particle models that do not require extremely tiny coupling constants. We find the compatibility of the theoretical predictions with the IceCube results when the astrophysical flux has a cutoff of the order of 100 TeV (broken power law). In this case the most energetic part of the spectrum (PeV neutrinos) is due to an extra component such as the decay of a very massive dark matter component. Due to the low statistics at our disposal we have considered for simplicity the equivalence between deposited and neutrino energy, however such approximation does not affect dramatically the qualitative results. Of course, a purely astrophysical origin of the neutrino flux (no cutoff in energy below the PeV scale — unbroken power law) is still allowed. If future data will confirm the presence of a sharp cutoff above few PeV this would be in favor of a dark matter interpretation.

  12. C/2013 R1 (Lovejoy) at IR wavelengths and the variability of CO abundances among Oort Cloud comets

    SciTech Connect (OSTI)

    Paganini, L.; Mumma, M. J.; Villanueva, G. L.; Bonev, B. P.; DiSanti, M. A.; Keane, J. V.; Meech, K. J.; Blake, G. A.; Gibb, E. L.

    2014-08-20

    We report production rates, rotational temperatures, and related parameters for gases in C/2013 R1 (Lovejoy) using the Near InfraRed SPECtrometer at the Keck Observatory, on six UT dates spanning heliocentric distances (R{sub h} ) that decreased from 1.35 AU to 1.16 AU (pre-perihelion). We quantified nine gaseous species (H{sub 2}O, OH*, CO, CH{sub 4}, HCN, C{sub 2}H{sub 6}, CH{sub 3}OH, NH{sub 3}, and NH{sub 2}) and obtained upper limits for two others (C{sub 2}H{sub 2} and H{sub 2}CO). Compared with organics-normal comets, our results reveal highly enriched CO, (at most) slightly enriched CH{sub 3}OH, C{sub 2}H{sub 6}, and HCN, and CH{sub 4} consistent with {sup n}ormal{sup ,} yet depleted, NH{sub 3}, C{sub 2}H{sub 2}, and H{sub 2}CO. Rotational temperatures increased from ?50 K to ?70 K with decreasing R{sub h} , following a power law in R{sub h} of 2.0 0.2, while the water production rate increased from 1.0 to 3.9 10{sup 28} molecules s{sup 1}, following a power law in R{sub h} of 4.7 0.9. The ortho-para ratio for H{sub 2}O was 3.01 0.49, corresponding to spin temperatures (T {sub spin}) ? 29 K (at the 1? level). The observed spatial profiles for these emissions showed complex structures, possibly tied to nucleus rotation, although the cadence of our observations limits any definitive conclusions. The retrieved CO abundance in Lovejoy is more than twice the median value for comets in our IR survey, suggesting this comet is enriched in CO. We discuss the enriched value for CO in comet C/2013 R1 in terms of the variability of CO among Oort Cloud comets.

  13. Systematic structure of the neutron drip-line {sup 22}C nucleus

    SciTech Connect (OSTI)

    Ismail, Atef; Cheong, Lee Yen; Yahya, Noorhana; Tammam, M.

    2014-10-24

    In the present work we systematically discuss the nuclear structure of the the heaviest particle-bound carbon isotope, {sup 22}C. The ground state wave function of the carbon isotope is calculated using the {sup 20}C core plus two-valence neutron based on a phenomenological mean-field MF potential. We apply the deduced wave function to provide the nuclear matter density which is necessary in the calculations of the total reaction cross section. Calculations show that there is a reasonable good description of the experimental binding energy BE and root-mean square RMS radius. The exotic structure and configuration of the ground state carbon isotope is explained and a consistent explanation on the two-neutron halo (Borromean) nucleus is given.

  14. Mechanism of elastic and inelastic proton scattering on a {sup 15}C nucleus in diffraction theory

    SciTech Connect (OSTI)

    Ibraeva, E. T.; Zhusupov, M. A.; Imambekov, O.

    2012-11-15

    The amplitudes for elastic and inelastic proton scattering on the neutron-rich nucleus {sup 15}C (to its J{sup {pi}} = 5/2{sup +} level in the latter case) in inverse kinematics were calculated within Glauber diffraction theory. First- and second-order terms were taken into account in the multiple-scattering operator. The {sup 15}C wave function in the multiparticle shell model was used. This made it possible to calculate not only respective differential cross sections but also the contribution of proton scattering on nucleons occurring in different shells. The differential cross sections for elastic and inelastic scattering were calculated at the energies of 0.2, 0.6, and 1 GeV per nucleon.

  15. Competing decay modes of a high-spin isomer in the proton-unbound nucleus ??Ta*

    SciTech Connect (OSTI)

    Carroll, R. J.; Page, R. D.; Joss, D. T.; Uusitalo, J.; Darby, I. G.; Andgren, K.; Cederwall, B.; Eeckhaudt, S.; Grahn, T.; Gray-Jones, C.; Greenlees, P. T.; Hadinia, B.; Jones, P. M.; Julin, R.; Juutinen, S.; Leino, M.; Leppnen, A. -P.; Nyman, M.; O'Donnell, D.; Pakarinen, J.; Rahkila, P.; Sandzelius, M.; Sarn, J.; Scholey, C.; Seweryniak, D.; Simpson, J.

    2015-01-01

    An isomeric state at high spin and excitation energy was recently observed in the proton-unbound nucleus 158Ta. This state was observed to decay by both ? and ? decay modes. The large spin change required to decay via ?-ray emission incurs a lifetime long enough for ? decay to compete. The ? decay has an energy of 8644(11) keV, which is among the highest observed in the region, a partial half-life of 440(70) ?s and changes the spin by 11?. In this study, additional evidence supporting the assignment of this ? decay to the high-spin isomer in 158Ta will be presented.

  16. Evidence of a slight nuclear transparency in the alpha-nucleus systems

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Chamon, L. C.; Gasques, L. R.; Nobre, G. P. A.; Rossi, Jr., E. S.; deBoer, R. J.; Seymour, C.; Wiescher, M.; Kiss, G. G.

    2015-02-19

    In earlier works, we proposed a model for the nuclear potential of the α + α and α + ¹²C systems. In addition, this theoretical model successfully described data related to the elastic and inelastic scattering processes as well as resonances that correspond to the capture reaction channel. In the present work, we extend the same model to obtain bare nuclear potentials for several α-nucleus systems. We adopt this parameter-free interaction to analyze fusion, elastic, and inelastic scattering data within the context of the coupled-channel formalism. Our results indicate that, for these systems, the absorption of flux of the elasticmore » channel at internal distances of interaction is not complete. In addition, we present new experimental angular distributions for the 2⁺ inelastic target excitation of α on ¹²⁰,¹³⁰Te.« less

  17. Spatially resolved spectra of the 'teacup' active galactic nucleus: tracing the history of a dying quasar

    SciTech Connect (OSTI)

    Gagne, J. P.; Crenshaw, D. M.; Fischer, T. C.; Kraemer, S. B.; Schmitt, H. R.; Keel, W. C.; Rafter, S.; Bennert, V. N.; Schawinski, K.

    2014-09-01

    The Sloan Digital Sky Survey (SDSS) Galaxy Zoo project has revealed a number of spectacular galaxies possessing extended emission-line regions (EELRs), the most famous being Hanny's Voorwerp galaxy. We present another EELR object discovered in the SDSS endeavor: the Teacup active galactic nucleus (AGN). Nicknamed for its EELR, which has a 'handle'-like structure protruding 15 kpc into the northeast quadrant of the galaxy. We analyze the physical conditions of this galaxy with long-slit, ground-based spectroscopy from the Lowell, Lick, and KPNO observatories. With the Lowell 1.8 m Perkin's telescope we took multiple observations at different offset positions, allowing us to recover spatially resolved spectra across the galaxy. Line diagnostics indicate the ionized gas is photoionized primarily by the AGN. Additionally we are able to derive the hydrogen density from the [S II] ?6716/?6731 ratio. We generated two-component photoionization models for each spatially resolved Lowell spectrum. These models allow us to calculate the AGN bolometric luminosity seen by the gas at different radii from the nuclear center of the Teacup. Our results show a drop in bolometric luminosity by more than two orders of magnitude from the EELR to the nucleus, suggesting that the AGN has decreased in luminosity by this amount in a continuous fashion over 46,000 yr, supporting the case for a dying AGN in this galaxy independent of any IR based evidence. We demonstrate that spatially resolved photoionization modeling could be applied to EELRs to investigate long timescale variability.

  18. Modeling hot gas flow in the low-luminosity active galactic nucleus of NGC 3115

    SciTech Connect (OSTI)

    Shcherbakov, Roman V.; Reynolds, Christopher S.; Wong, Ka-Wah; Irwin, Jimmy A.

    2014-02-20

    Based on the dynamical black hole (BH) mass estimates, NGC 3115 hosts the closest billion solar mass BH. Deep studies of the center revealed a very underluminous active galactic nucleus (AGN) immersed in an old massive nuclear star cluster. Recent 1 Ms Chandra X-ray visionary project observations of the NGC 3115 nucleus resolved hot tenuous gas, which fuels the AGN. In this paper we connect the processes in the nuclear star cluster with the feeding of the supermassive BH. We model the hot gas flow sustained by the injection of matter and energy from the stars and supernova explosions. We incorporate electron heat conduction as the small-scale feedback mechanism, the gravitational pull of the stellar mass, cooling, and Coulomb collisions. Fitting simulated X-ray emission to the spatially and spectrally resolved observed data, we find the best-fitting solutions with ?{sup 2}/dof = 1.00 for dof = 236 both with and without conduction. The radial modeling favors a low BH mass <1.3 10{sup 9} M {sub ?}. The best-fitting supernova rate and the best-fitting mass injection rate are consistent with their expected values. The stagnation point is at r {sub st} ? 1'', so that most of the gas, including the gas at a Bondi radius r{sub B} = 2''-4'', outflows from the region. We put an upper limit on the accretion rate at 2 10{sup 3} M {sub ?} yr{sup 1}. We find a shallow density profile n?r {sup ?} with ? ? 1 over a large dynamic range. This density profile is determined in the feeding region 0.''5-10'' as an interplay of four processes and effects: (1) the radius-dependent mass injection, (2) the effect of the galactic gravitational potential, (3) the accretion flow onset at r ? 1'', and (4) the outflow at r ? 1''. The gas temperature is close to the virial temperature T{sub v} at any radius.

  19. Dimensions and aspect ratios of natural ice crystals

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Um, J.; McFarquhar, G. M.; Hong, Y. P.; Lee, S. -S.; Jung, C. H.; Lawson, R. P.; Mo, Q.

    2015-04-15

    During the 2006 Tropical Warm Pool International Cloud Experiment (TWP-ICE) in the tropics, the 2008 Indirect and Semi-Direct Aerosol Campaign (ISDAC) in the Arctic, and the 2010 Small PARTicles In CirrUS (SPARTICUS) campaign at mid-latitudes, high-resolution images of ice crystals were recorded by a Cloud Particle Imager at temperatures (T) between -87 and 0 °C. The projected maximum dimension (D'), length (L'), and width (W') of pristine columns, plates, and component bullets of bullet rosettes were measured using newly developed software, the Ice Crystal Ruler. The number of bullets in each bullet rosette was also measured. Column crystals were furthermore » distinguished as either horizontally oriented columns or columns with other orientations to eliminate any orientation effect on the measured dimensions. The dimensions and aspect ratios (AR, the dimension of the major axis divided by the dimension of the minor axis) of crystals were determined as functions of temperature, geophysical location, and type of cirrus. Dimensions of crystals generally increased with temperature. Columns and bullets had larger dimensions (i.e., W') of the minor axis (i.e., a axis) for a given dimension (i.e., D' orL') of the major axis (i.e., c axis), and thus smaller AR, as T increased, whereas this trend did not occur for plate crystals. The average number of branches in bullet rosettes was 5.50 ± 1.35 during three campaigns and 6.32 ± 1.34 (5.46 ± 1.34; 4.95 ± 1.01) during TWP-ICE (SPARTICUS; ISDAC). The AR of bullets increased with the number of branches in bullet rosettes. Most dimensions of crystals and ARs of columnar crystals measured during SPARTICUS were larger than those measured during TWP-ICE and ISDAC at −67 < T < -35 °C and at −40 < T < −15 °C, respectively. The relative occurrence of varying pristine habits depended strongly on cirrus type (i.e., anvil or non-anvil clouds), with plates especially occurring more frequently in anvils. The L–W relationships of columns derived using current data exhibited a strong dependence on temperature; similar relationships determined in previous studies were within the range of the current data.« less

  20. Dimensions and aspect ratios of natural ice crystals

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Um, J.; McFarquhar, G. M.; Hong, Y. P.; Lee, S. -S.; Jung, C. H.; Lawson, R. P.; Mo, Q.

    2014-12-10

    During the 2006 Tropical Warm Pool International Cloud Experiment (TWP-ICE) in the Tropics, the 2008 Indirect and Semi-Direct Aerosol Campaign (ISDAC) in the Arctic, and the 2010 Small PARTicles In CirrUS (SPARTICUS) campaign in mid-latitudes, high-resolution images of ice crystals were recorded by a Cloud Particle Imager at temperatures (T) between -87 and 0 °C. The projected maximum dimension (D'), length (L'), and width (W') of pristine columns, plates, and component bullets of bullet rosettes were measured using newly developed software, the Ice Crystal Ruler. The number of bullets in each bullet rosette was also measured. Column crystals were furthermore » distinguished as either horizontally oriented columns or columns with other orientations to eliminate any orientation effect on the measured dimensions. Dimensions and aspect ratios (AR, dimension of major axis divided by dimension of minor axis) of crystals were determined as functions of temperature, geophysical location, and type of cirrus. Dimensions of crystals generally increased as temperature increased. Columns and bullets had larger dimensions (i.e., W') of the minor axis (i.e., a axis) for a given dimension (i.e., D' or L') of the major axis (i.e., c axis), and thus smaller AR, as T increased, whereas this trend did not occur for plate crystals. The average number of branches in bullet rosettes was 5.50±1.35 during three campaigns and 6.32±1.34 (5.46±1.34; 4.95±1.01) during TWP-ICE (SPARTICUS; ISDAC). The AR of bullets increased with the number of branches in bullet rosettes. Most dimensions of crystals and ARs of columnar crystals measured during SPARTICUS were larger than those measured during TWP-ICE and ISDAC at −67 < T < −35 °C and at −40 < T < −15 °C, respectively. The relative occurrence of varying pristine habits depended strongly on cirrus type (i.e., anvil or non-anvil clouds), with plates especially occurring more frequently in anvils. The L–W relationships of columns derived using current data exhibited a strong dependence on temperature; similar relationship determined in previous studies were within the range of the current data.« less

  1. Asteroseismic estimate of helium abundance of a solar analog binary system

    SciTech Connect (OSTI)

    Verma, Kuldeep; Antia, H. M.; Faria, Joo P.; Monteiro, Mrio J. P. F. G.; Basu, Sarbani; Mazumdar, Anwesh; Appourchaux, Thierry; Chaplin, William J.; Garca, Rafael A.

    2014-08-01

    16 Cyg A and B are among the brightest stars observed by Kepler. What makes these stars more interesting is that they are solar analogs. 16 Cyg A and B exhibit solar-like oscillations. In this work we use oscillation frequencies obtained using 2.5 yr of Kepler data to determine the current helium abundance of these stars. For this we use the fact that the helium ionization zone leaves a signature on the oscillation frequencies and that this signature can be calibrated to determine the helium abundance of that layer. By calibrating the signature of the helium ionization zone against models of known helium abundance, the helium abundance in the envelope of 16 Cyg A is found to lie in the range of 0.231 to 0.251 and that of 16 Cyg B lies in the range of 0.218 to 0.266.

  2. Earth-abundant Solar Cells: Can Iron Complexes Serve as Photosensitize...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Earth-abundant Solar Cells: Can Iron Complexes Serve as Photosensitizers in DSSCs November 10, 2015 11:00AM to 12:00PM Presenter Elena Jakubikova, North Carolina State University...

  3. A man-made enhanced geothermal system (EGS) can extract the abundant...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    man-made enhanced geothermal system (EGS) can extract the abundant heat resource tens of thousands of feet below the surface and put it to good use. This would require: With an ...

  4. High-Performance Thermoelectric Devices Based on Abundant Silicide Materials for Vehicle Waste Heat Recovery

    Broader source: Energy.gov [DOE]

    Development of high-performance thermoelectric devices for vehicle waste heat recovery will include fundamental research to use abundant promising low-cost thermoelectric materials, thermal management and interfaces design, and metrology

  5. Discovery of a ternary pseudobrookite phase in the earth-abundant...

    Office of Scientific and Technical Information (OSTI)

    Title: Discovery of a ternary pseudobrookite phase in the earth-abundant TiZnO system Authors: Perry, Nicola H. ; Stevanovic, Vladan ; Lime, Linda Y. ; Mason, Thomas O. 1 ; CSM) ...

  6. Discovery of bridgmanite, the most abundant mineral in Earth, in a shocked

    Office of Scientific and Technical Information (OSTI)

    meteorite (Journal Article) | SciTech Connect SciTech Connect Search Results Journal Article: Discovery of bridgmanite, the most abundant mineral in Earth, in a shocked meteorite Citation Details In-Document Search Title: Discovery of bridgmanite, the most abundant mineral in Earth, in a shocked meteorite Authors: Tschauner, Oliver ; Ma, Chi ; Beckett, John R. ; Prescher, Clemens ; Prakapenka, Vitali B. ; Rossman, George R. [1] ; UNLV) [2] ; CIT) [2] + Show Author Affiliations (UC) (

  7. Realizing three-dimensional artificial spin ice by stacking planar nano-arrays

    SciTech Connect (OSTI)

    Chern, Gia-Wei; Reichhardt, Charles; Nisoli, Cristiano

    2014-01-06

    Artificial spin ice is a frustrated magnetic two-dimensional nano-material, recently employed to study variety of tailor-designed unusual collective behaviours. Recently proposed extensions to three dimensions are based on self-assembly techniques and allow little control over geometry and disorder. We present a viable design for the realization of a three-dimensional artificial spin ice with the same level of precision and control allowed by lithographic nano-fabrication of the popular two-dimensional case. Our geometry is based on layering already available two-dimensional artificial spin ice and leads to an arrangement of ice-rule-frustrated units, which is topologically equivalent to that of the tetrahedra in a pyrochlore lattice. Consequently, we show, it exhibits a genuine ice phase and its excitations are, as in natural spin ice materials, magnetic monopoles interacting via Coulomb law.

  8. The Ne-to-O abundance ratio of the interstellar medium from IBEX-Lo observations

    SciTech Connect (OSTI)

    Park, J.; Kucharek, H.; Mbius, E.; Leonard, T.; Bzowski, M.; Sok?, J. M.; Kubiak, M. A.; Fuselier, S. A.; McComas, D. J.

    2014-11-01

    In this paper we report on a two-year study to estimate the Ne/O abundance ratio in the gas phase of the local interstellar cloud (LIC). Based on the first two years of observations with the Interstellar Boundary Explorer, we determined the fluxes of interstellar neutral (ISN) O and Ne atoms at the Earth's orbit in spring 2009 and 2010. A temporal variation of the Ne/O abundance ratio at the Earth's orbit could be expected due to solar cycle-related effects such as changes of ionization. However, this study shows that there is no significant change in the Ne/O ratio at the Earths orbit from 2009 to 2010. We used time-dependent survival probabilities of the ISNs to calculate the Ne/O abundance ratio at the termination shock. Then we estimated the Ne/O abundance ratio in the gas phase of the LIC with the use of filtration factors and the ionization fractions. From our analysis, the Ne/O abundance ratio in the LIC is 0.33 0.07, which is in agreement with the abundance ratio inferred from pickup-ion measurements.

  9. Using Doppler spectra to separate hydrometeor populations and analyze ice precipitation in multilayered mixed-phase clouds

    SciTech Connect (OSTI)

    Rambukkange, Mahlon P.; Verlinde, J.; Eloranta, E. W.; Flynn, Connor J.; Clothiaux, Eugene E.

    2011-01-31

    Multimodality of cloud radar Doppler spectra is used to partition cloud particle phases and to separate distinct ice populations in the radar sample volume, thereby facilitating analysis of individual ice showers in multilayered mixed-phase clouds. A 35-GHz cloud radar located at Barrow, Alaska, during the Mixed-Phase Arctic Cloud Experiment collected the Doppler spectra. Data from a pair of collocated depolarization lidars confirmed the presence of two liquid cloud layers reported in this study. Surprisingly, both of these cloud layers were embedded in ice precipitation yet maintained their liquid. Our spectral separation of the ice precipitation yielded two distinct ice populations: ice initiated within the two liquid cloud layers and ice precipitation formed in higher cloud layers. Comparisons of ice fall velocity versus radar reflectivity relationships derived for distinct showers reveal that a single relationship might not properly represent the ice showers during this period.

  10. Prediction of Ice Crystal Number in Community Atmospheric Model (CAM3.0)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Prediction of Ice Crystal Number in Community Atmospheric Model (CAM3.0) Liu, Xiaohong Pacific Northwest National Laboratory Ghan, Steven Pacific Northwest National Laboratory Wang, M University of Michigan Penner, Joyce University of Michigan Category: Modeling A prognostic equation of ice crystal number concentrations is implemented in the Community Atmospheric Model (CAM3.0) with the aim to study the aerosol effects on climate through changing the ice cloud properties. The microphysical

  11. A PHOTOMETRIC SYSTEM FOR DETECTION OF WATER AND METHANE ICES ON KUIPER BELT OBJECTS

    SciTech Connect (OSTI)

    Trujillo, Chadwick A.; Sheppard, Scott S.; Schaller, Emily L. E-mail: sheppard@dtm.ciw.edu

    2011-04-01

    We present a new near-infrared photometric system for detection of water ice and methane ice in the solar system. The system consists of two medium-band filters in the K-band region of the near-infrared, which are sensitive to water ice and methane ice, plus continuum observations in the J band and Y band. The primary purpose of this system is to distinguish between three basic types of Kuiper Belt Objects (KBOs)-those rich in water ice, those rich in methane ice, and those with little absorbance. In this work, we present proof-of-concept observations of 51 KBOs using our filter system, 21 of which have never been observed in the near-infrared spectroscopically. We show that our custom photometric system is consistent with previous spectroscopic observations while reducing telescope observing time by a factor of {approx}3. We use our filters to identify Haumea collisional family members, which are thought to be collisional remnants of a much larger body and are characterized by large fractions of water ice on their surfaces. We add 2009 YE{sub 7} to the Haumea collisional family based on our water ice band observations (J - H{sub 2}O = -1.03 {+-} 0.27) which indicate a high amount of water ice absorption, our calculated proper orbital elements, and the neutral optical colors we measured, V - R = 0.38 {+-} 0.04, which are all consistent with the rest of the Haumea family. We identify several objects dynamically similar to Haumea as being distinct from the Haumea family as they do not have water ice on their surfaces. In addition, we find that only the largest KBOs have methane ice, and Haumea itself has significantly less water ice absorption than the smaller Haumea family members. We find no evidence for other families in the Kuiper Belt.

  12. Statement of Work (SOW) Template (Combined EIR/ICE Support Contractor) |

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Department of Energy Statement of Work (SOW) Template (Combined EIR/ICE Support Contractor) Statement of Work (SOW) Template (Combined EIR/ICE Support Contractor) PDF icon Contractor SOW Template - EIR & ICE.pdf More Documents & Publications External Independent Review (EIR) Report Template External Independent Review (EIR) Standard Operating Procedure (SOP) September 2010 External Independent Review (EIR) Standard Operating Procedure (SOP) Septemebr 2010

  13. Heterogeneous ice nucleation and water uptake by field-collected atmospheric particles below 273 K

    SciTech Connect (OSTI)

    Wang, Bingbing; Laskin, Alexander; Roedel, Tobias R.; Gilles, Marry K.; Moffet, Ryan C.; Tivanski, Alexei V.; Knopf, Daniel A.

    2012-09-25

    Atmospheric ice formation induced by particles with complex chemical and physical properties through heterogeneous nucleation is not well understood. Heterogeneous ice nucleation and water uptake by ambient particles collected from urban environments in Los Angeles and Mexico City are presented. Using a vapour controlled cooling system equipped with an optical microscopy, the range of onset conditions for ice nucleation and water uptake by the collected particles was determined as a function of temperature (200{273 K) and relative humidity with respect to ice (RHice) up to water saturation. Three distinctly different types of authentic atmospheric particles were investigated including soot particles associated with organics/inorganics, inorganic particles of marine origin coated with organic material, and Pb/Zn containing inorganic particles apportioned to anthropogenic emissions relevant to waste incineration. Single particle characterization was provided by micro-spectroscopic analyses using computer controlled scanning electron microscopy with energy dispersive analysis of X-rays (CCSEM/EDX) and scanning transmission X-ray microscopy with near edge X-ray absorption ne structure spectroscopy (STXM/NEXAFS). Above 230 K, signicant differences in water uptake and immersion freezing effciencies of the different particle types were observed. Below 230 K, the particles exhibited high deposition ice nucleation effciencies and formed ice at RHice values well below homogeneous ice nucleation limits. The data show that the chemical composition of these eld{collected particles plays an important role in determining water uptake and immersion freezing. Heterogeneous ice nucleation rate coeffcients, cumulative ice nuclei (IN) spectrum, and IN activated fraction for deposition ice nucleation are derived. The presented ice nucleation data demonstrate that anthropogenic and marine particles comprising of various chemical and physical properties exhibit distinctly different ice nucleation effciencies and can serve as effcient IN at atmospheric conditions typical for cirrus and mixed phase clouds. This indicates a potential link between human activities and cloud formation, and thus climate.

  14. Purchasing Energy-Efficient Air-Cooled Ice Machines | Department of Energy

    Energy Savers [EERE]

    Products & Technologies » Energy-Efficient Products » Covered Product Categories » Purchasing Energy-Efficient Air-Cooled Ice Machines Purchasing Energy-Efficient Air-Cooled Ice Machines The Federal Energy Management Program (FEMP) provides acquisition guidance for air-cooled ice machines, a product category covered by ENERGY STAR efficiency requirements. Federal laws and requirements mandate that agencies purchase ENERGY STAR-qualified products or FEMP-designated products in all product

  15. Long-range azimuthal correlations in protonproton and protonnucleus collisions from the incoherent scattering of partons

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Ma, Guo -Liang; Bzdak, Adam

    2014-11-04

    In this study, we show that the incoherent elastic scattering of partons, as present in a multi-phase transport model (AMPT), with a modest partonparton cross-section of ? = 1.5 3 mb, naturally explains the long-range two-particle azimuthal correlation as observed in protonproton and protonnucleus collisions at the Large Hadron Collider.

  16. Bio-based Deicing/Anti-Icing Fluids - Energy Innovation Portal

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Biomass and Biofuels Biomass and Biofuels Find More Like This Return to Search Bio-based DeicingAnti-Icing Fluids Battelle Memorial Institute Contact BMI About This...

  17. FELIX: advances in modeling forward and inverse ice-sheet problems...

    Office of Scientific and Technical Information (OSTI)

    Title: FELIX: advances in modeling forward and inverse ice-sheet problems. Abstract not provided. Authors: Salinger, Andrew G. ; Perego, Mauro ; Hoffman, Mattew ; Leng, Wei ; ...

  18. Development of a land ice core for the Model for Prediction Across...

    Office of Scientific and Technical Information (OSTI)

    Citation Details In-Document Search Title: Development of a land ice core for the Model ... Sponsoring Org: DOELANL Country of Publication: United States Language: English Subject: ...

  19. Microsoft PowerPoint - TWP-ICE_2006Nov_Rad.ppt

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    TWP-ICE: Surface Radiation Chuck Long PNNL ARM Atmospheric Radiation Measurement Radiation Sites ARM Atmospheric Radiation Measurement Available Data ARM Atmospheric Radiation ...

  20. Radiation damage and associated phase change effect on photodesorption rates from icesLy? studies of the surface behavior of CO{sub 2}(ice)

    SciTech Connect (OSTI)

    Yuan, Chunqing; Yates, John T. Jr.

    2014-01-01

    Photodesorption from a crystalline film of CO{sub 2}(ice) at 75 K has been studied using Ly? (10.2 eV) radiation. We combine quantitative mass spectrometric studies of gases evolved and transmission IR studies of species trapped in the ice. Direct CO desorption is observed from the primary CO{sub 2} photodissociation process, which occurs promptly for CO{sub 2} molecules located on the outermost surface of the ice (Process I). As the fluence of Ly? radiation increases to ?5.5 10{sup 17} photons cm{sup 2}, extensive damage to the crystalline ice occurs and photo-produced CO molecules from deeper regions (Process II) are found to desorb at a rapidly increasing rate, which becomes two orders of magnitude greater than Process I. It is postulated that deep radiation damage to produce an extensive amorphous phase of CO{sub 2} occurs in the 50 nm ice film and that CO (and CO{sub 2}) diffusive transport is strongly enhanced in the amorphous phase. Photodesorption in Process II is a combination of electronic and thermally activated processes. Radiation damage in crystalline CO{sub 2} ice has been monitored by its effects on the vibrational line shapes of CO{sub 2}(ice). Here the crystalline-to-amorphous phase transition has been correlated with the occurrence of efficient molecular transport over long distances through the amorphous phase of CO{sub 2}(ice). Future studies of the composition of the interstellar region, generated by photodesorption from ice layers on grains, will have to consider the significant effects of radiation damage on photodesorption rates.

  1. MULTIDIMENSIONAL CHEMICAL MODELING OF YOUNG STELLAR OBJECTS. III. THE INFLUENCE OF GEOMETRY ON THE ABUNDANCE AND EXCITATION OF DIATOMIC HYDRIDES

    SciTech Connect (OSTI)

    Bruderer, S.; Benz, A. O.; Staeuber, P.; Doty, S. D.

    2010-09-10

    The Herschel Space Observatory enables observations in the far-infrared at high spectral and spatial resolution. A particular class of molecules will be directly observable: light diatomic hydrides and their ions (CH, OH, SH, NH, CH{sup +}, OH{sup +}, SH{sup +}, NH{sup +}). These simple constituents are important both for the chemical evolution of the region and as tracers of high-energy radiation. If outflows of a forming star erode cavities in the envelope, protostellar far-UV (FUV; 6 < E{sub {gamma}} < 13.6 eV) radiation may escape through such low-density regions. Depending on the shape of the cavity, the FUV radiation then irradiates the quiescent envelope in the walls along the outflow. The chemical composition in these outflow walls is altered by photoreactions and heating via FUV photons in a manner similar to photo-dominated regions. In this work, we study the effect of cavity shapes, outflow density, and of a disk with the two-dimensional chemical model of a high-mass young stellar object introduced in the second paper in this series. The model has been extended with a self-consistent calculation of the dust temperature and a multi-zone escape probability method for the calculation of the molecular excitation and the prediction of line fluxes. We find that the shape of the cavity is particularly important in the innermost part of the envelope, where the dust temperatures are high enough ({approx}>100 K) for water ice to evaporate. If the cavity shape allows FUV radiation to penetrate this hot-core region, the abundance of FUV-destroyed species (e.g., water) is decreased. On larger scales, the shape of the cavity is less important for the chemistry in the outflow wall. In particular, diatomic hydrides and their ions CH{sup +}, OH{sup +}, and NH{sup +} are enhanced by many orders of magnitude in the outflow walls due to the combination of high gas temperatures and rapid photodissociation of more saturated species. The enhancement of these diatomic hydrides is sufficient for a detection using the HIFI and PACS instruments on board Herschel. The effect of X-ray ionization on the chemistry is found to be small, due to the much larger luminosity in FUV bands compared to X-rays.

  2. Observed hemispheric asymmetry in global sea ice changes

    SciTech Connect (OSTI)

    Cavalieri, D.J.; Gloersen, P.; Parkinson, C.L.; Comiso, J.C.; Zwally, H.J.

    1997-11-07

    From November 1978 through December 1996, the areal extent of sea ice decreased by 2.9 {+-} 0.4 percent decade in the Arctic and increased by 1.3 {+-} 0.2 percent per decade in the Antarctic. The observed hemispheric asymmetry in these trends is consistent with a modeled response to a carbon dioxide-induced climate warming. The interannual variations, which are 2.3 percent of the annual mean in the Arctic, with a predominant period of about 5 years, and 3.4 percent of the annual mean in the Antarctic, with a predominant period of about 3 years, are uncorrelated. 29 refs., 2 figs., 1 tab.

  3. Impact of Ice Crystal Roughness on Satellite Retrieved Cloud Properties

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Ice Crystal Roughness on Satellite Retrieved Cloud Properties P. Minnis 1 , P. W. Heck 2 , R. F. Arduini 3 , R. Palikonda 3 , J. K. Ayers 3 , M. M. Khaiyer 3 , P. Yang 4 , Y. Xie 4 3 Science Systems & Applications, Inc. Hampton, VA 1 NASA Langley Research Center Hampton, VA Current Cirrus Models Inadequate Cirrus cloud optical depths τ (heights z e ) are often over (under) estimated when derived from solar reflectances. In situ data suggest smaller asymmetry factors, g, than used in most

  4. SGP and TWP (Manus) Ice Cloud Vertical Velocities

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Kalesse, Heike

    Daily netcdf-files of ice-cloud dynamics observed at the ARM sites at SGP (Jan1997-Dec2010) and Manus (Jul1999-Dec2010). The files include variables at different time resolution (10s, 20min, 1hr). Profiles of radar reflectivity factor (dbz), Doppler velocity (vel) as well as retrieved vertical air motion (V_air) and reflectivity-weighted particle terminal fall velocity (V_ter) are given at 10s, 20min and 1hr resolution. Retrieved V_air and V_ter follow radar notation, so positive values indicate downward motion. Lower level clouds are removed, however a multi-layer flag is included.

  5. SGP and TWP (Manus) Ice Cloud Vertical Velocities

    SciTech Connect (OSTI)

    Kalesse, Heike

    2013-06-27

    Daily netcdf-files of ice-cloud dynamics observed at the ARM sites at SGP (Jan1997-Dec2010) and Manus (Jul1999-Dec2010). The files include variables at different time resolution (10s, 20min, 1hr). Profiles of radar reflectivity factor (dbz), Doppler velocity (vel) as well as retrieved vertical air motion (V_air) and reflectivity-weighted particle terminal fall velocity (V_ter) are given at 10s, 20min and 1hr resolution. Retrieved V_air and V_ter follow radar notation, so positive values indicate downward motion. Lower level clouds are removed, however a multi-layer flag is included.

  6. Investigation of the {sup 128}Ba nucleus with the (p,t) reaction

    SciTech Connect (OSTI)

    Pascu, S.; Cata-Danil, Gh.; Bucurescu, D.; Marginean, N.; Zamfir, N. V.; Graw, G.; Gollwitzer, A.; Hofer, D.; Valnion, B. D.

    2009-06-15

    The low lying states in {sup 128}Ba have been investigated for the first time with the {sup 130}Ba(p,t){sup 128}Ba reaction. The experiment was performed at the Munich Q3D magnetic spectrograph with a 25-MeV proton beam and a high-resolution, 1.5-m-long focal plane detector. As a result of this experiment 27 excited levels with energies below 3.7 MeV have been observed for the first time, significantly increasing (by {approx}50%) the number of levels observed in {sup 128}Ba. Angular distributions of tritons were measured and their comparison with the distorted wave Born approximation calculation allowed in most cases spin and parity assignments for the nuclear levels. The experimental two-neutron transition strengths with transferred angular momentum L=0 and 2 are compared with the predictions of the IBA-1 model with a new set of parameters. The results indicate for the first time from a hadronic probe perspective a transitional structure close to the O(6) symmetry for the {sup 128}Ba nucleus, confirming previous conclusions of {gamma}-ray spectroscopy studies.

  7. Investigation of low-lying electric dipole strength in the semimagic nucleus {sup 44}Ca

    SciTech Connect (OSTI)

    Isaak, J.; Fritzsche, M.; Hartmann, T.; Pietralla, N.; Romig, C.; Sonnabend, K.; Savran, D.; Galaviz, D.; Kamerdzhiev, S.; Kelley, J. H.; Kwan, E.; Rusev, G.; Tonchev, A. P.; Tornow, W.; Zilges, A.

    2011-03-15

    The dipole-strength distribution in the semimagic nucleus {sup 44}Ca has been measured up to 10 MeV excitation energy in photon-scattering experiments using bremsstrahlung and monoenergetic 100% linearly polarized photon beams. The combination of both measurements allows a clear determination of spin and parity quantum numbers of the excited states as well as absolute cross sections and transition probabilities. The results show that the majority of the dipole strength in {sup 44}Ca below 10 MeV is due to E1 transitions while M1 strength plays only a minor role. The experimental results are compared to the strength in the neighboring doubly magic nuclei {sup 40,48}Ca and to microscopic calculations within the extended theory of finite Fermi systems in order to investigate the evolution of the low-lying E1 strength in this isotopic chain. Both, experiment and calculations, show a nontrivial dependence of the total E1 strength as a function of the neutron number.

  8. MHD SIMULATIONS OF ACTIVE GALACTIC NUCLEUS JETS IN A DYNAMIC GALAXY CLUSTER MEDIUM

    SciTech Connect (OSTI)

    Mendygral, P. J.; Jones, T. W.; Dolag, K.

    2012-05-10

    We present a pair of three-dimensional magnetohydrodynamical simulations of intermittent jets from a central active galactic nucleus (AGN) in a galaxy cluster extracted from a high-resolution cosmological simulation. The selected cluster was chosen as an apparently relatively relaxed system, not having undergone a major merger in almost 7 Gyr. Despite this characterization and history, the intracluster medium (ICM) contains quite active 'weather'. We explore the effects of this ICM weather on the morphological evolution of the AGN jets and lobes. The orientation of the jets is different in the two simulations so that they probe different aspects of the ICM structure and dynamics. We find that even for this cluster, which can be characterized as relaxed by an observational standard, the large-scale, bulk ICM motions can significantly distort the jets and lobes. Synthetic X-ray observations of the simulations show that the jets produce complex cavity systems, while synthetic radio observations reveal bending of the jets and lobes similar to wide-angle tail radio sources. The jets are cycled on and off with a 26 Myr period using a 50% duty cycle. This leads to morphological features similar to those in 'double-double' radio galaxies. While the jet and ICM magnetic fields are generally too weak in the simulations to play a major role in the dynamics, Maxwell stresses can still become locally significant.

  9. Performance of a stand-alone wind-electric ice maker for remote villages

    SciTech Connect (OSTI)

    Davis, H.C.; Brandemuehl, M.J.; Bergey, M.L.S.

    1995-01-01

    Two ice makers in the 1.1 metric tons per 24 hours (1.2 tons per day) size range were tested to determine their performance when directly coupled to a variable-frequency wind turbine generator. Initial tests were conducted using a dynamometer to simulate to wind to evaluate whether previously determined potential problems were significant and to define basic performance parameters. Field testing in Norman, Oklahoma, was completed to determine the performance of one of the ice makers under real wind conditions. As expected, the ice makers produced more ice at a higher speed than rated, and less ice at a lower speed. Due to the large start-up torque requirement of reciprocating compressors, the ice making system experienced a large start-up current and corresponding voltage drop which required a larger wind turbine that expected to provide the necessary current and voltage. Performance curves for ice production and power consumption are presented. A spreadsheet model was constructed to predict ice production at a user-defined site given the wind conditions for that location. Future work should include long-term performance tests and research on reducing the large start-up currents the system experiences when first coming on line.

  10. Experimental investigation of ice slurry flow pressure drop in horizontal tubes

    SciTech Connect (OSTI)

    Grozdek, Marino; Khodabandeh, Rahmatollah; Lundqvist, Per [Royal Institute of Technology, Department of Energy Technology, Division of Applied Thermodynamics and Refrigeration, Brinellvaegen 68, 10044 Stockholm (Sweden)

    2009-01-15

    Pressure drop behaviour of ice slurry based on ethanol-water mixture in circular horizontal tubes has been experimentally investigated. The secondary fluid was prepared by mixing ethyl alcohol and water to obtain initial alcohol concentration of 10.3% (initial freezing temperature -4.4 C). The pressure drop tests were conducted to cover laminar and slightly turbulent flow with ice mass fraction varying from 0% to 30% depending on test conditions. Results from flow tests reveal much higher pressure drop for higher ice concentrations and higher velocities in comparison to the single phase flow. However for ice concentrations of 15% and higher, certain velocity exists at which ice slurry pressure drop is same or even lower than for single phase flow. It seems that higher ice concentration delay flow pattern transition moment (from laminar to turbulent) toward higher velocities. In addition experimental results for pressure drop were compared to the analytical results, based on Poiseulle and Buckingham-Reiner models for laminar flow, Blasius, Darby and Melson, Dodge and Metzner, Steffe and Tomita for turbulent region and general correlation of Kitanovski which is valid for both flow regimes. For laminar flow and low buoyancy numbers Buckingham-Reiner method gives good agreement with experimental results while for turbulent flow best fit is provided with Dodge-Metzner and Tomita methods. Furthermore, for transport purposes it has been shown that ice mass fraction of 20% offers best ratio of ice slurry transport capability and required pumping power. (author)

  11. Ice storage rooftop retrofit for rooftop air conditioning

    SciTech Connect (OSTI)

    Tomlinson, J.J.; Jennings, L.W.

    1997-09-01

    A significant fraction of the floor space in commercial and federal buildings is cooled by single-package rooftop air conditioning units. These units are located on flat roofs and usually operate during the day under hot conditions. They are usually less energy efficient than a chiller system for building cooling. Several U.S. companies are developing systems that employ ice storage in conjunction with chillers to replace older, inefficient rooftop units for improved performance and minimal use of on-peak electricity. Although the low evaporator temperatures needed for ice making tend to reduce the efficiency of the chiller, the overall operating costs of the ice storage system may be lower than that of a packaged, conventional rooftop installation. One version of this concept, the Roofberg{reg_sign} System developed by the Calmac Corporation, was evaluated on a small building at Oak Ridge National Laboratory in Oak Ridge, Tennessee. The Roofberg system consists of a chiller, an ice storage tank, and one or more rooftop units whose evaporator coils have been adapted to use a glycol solution for cooling. The ice storage component decouples the cooling demand of the building from the operation of the chiller. Therefore, the chiller can operate at night (cooler, more efficient condensing temperatures) to meet a daytime cooling demand. This flexibility permits a smaller chiller to satisfy a larger peak cooling load. Further, the system can be operated to shift the cooling demand to off-peak hours when electricity from the utility is generated more efficiently and at lower cost. This Roofberg system was successfully installed last year on a small one-story office building in Oak Ridge and is currently being operated to cool the building. The building and system were sufficiently instrumented to allow a determination of the performance and efficiency of the Roofberg system. Although the energy efficiency of a simulated Roofberg storage/chiller concept operating in the full storage mode was about equal to what could be expected through a simple rooftop efficiency upgrade, the operating costs for the Roofberg system could be much more favorable depending on the utility rate structure. The ability of Roofberg to move much of the cooling load to off-peak periods enables it to take advantage of on-peak demand charges and time-of-use electricity rates. The Roofberg system, as installed, was able to reduce the on-peak energy use of the cooling system to 35% of the on-peak energy consumption of the baseline system. A comparative analysis of a rooftop replacement and Roofberg indicated that the Roofberg system on Building 2518 would be the better economic choice over a range of demand charges and on-off peak energy prices which are typical of utility rate tariffs for commercial buildings.

  12. CHEMICAL ABUNDANCE ANALYSIS OF A NEUTRON-CAPTURE ENHANCED RED GIANT IN THE BULGE PLAUT FIELD

    SciTech Connect (OSTI)

    Johnson, Christian I.; Rich, R. Michael [Department of Physics and Astronomy, UCLA, 430 Portola Plaza, Box 951547, Los Angeles, CA 90095-1547 (United States)] [Department of Physics and Astronomy, UCLA, 430 Portola Plaza, Box 951547, Los Angeles, CA 90095-1547 (United States); McWilliam, Andrew, E-mail: cijohnson@astro.ucla.edu, E-mail: rmr@astro.ucla.edu, E-mail: cjohnson@cfa.harvard.edu, E-mail: andy@obs.carnegiescience.edu [Observatories of the Carnegie Institution of Washington, Pasadena, CA 91101 (United States)] [Observatories of the Carnegie Institution of Washington, Pasadena, CA 91101 (United States)

    2013-09-20

    We present chemical abundances for 27 elements ranging from oxygen to erbium in the metal-poor ([Fe/H] = 1.67) bulge red giant branch star 2MASS 18174532-3353235. The results are based on equivalent width and spectrum synthesis analyses of a high-resolution (R ? 30, 000) spectrum obtained with the Magellan-MIKE spectrograph. While the light (Z ?< 30) element abundance patterns match those of similar metallicity bulge and halo stars, the strongly enhanced heavy element abundances are more similar to 'r-II' halo stars (e.g., CS 22892-052) typically found at [Fe/H] ?< 2.5. We find that the heaviest elements (Z ? 56) closely follow the scaled-solar r-process abundance pattern. We do not find evidence supporting significant s-process contributions; however, the intermediate mass elements (e.g., Y and Zr) appear to have been produced through a different process than the heaviest elements. The light and heavy element abundance patterns of 2MASS 18174532-3353235 are in good agreement with the more metal-poor r-process enhanced stars CS 22892-052 and BD +17{sup o}3248. 2MASS 18174532-3353235 also shares many chemical characteristics with the similar metallicity but comparatively ?-poor Ursa Minor dwarf galaxy giant COS 82. Interestingly, the Mo and Ru abundances of 2MASS 18174532-3353235 are also strongly enhanced and follow a similar trend recently found to be common in moderately metal-poor main-sequence turn-off halo stars.

  13. Early solar mass loss, opacity uncertainties, and the solar abundance problem

    SciTech Connect (OSTI)

    Guzik, Joyce Ann; Keady, John; Kilcrease, David

    2009-01-01

    Solar models calibrated with the new element abundance mixture of Asplund et al. published in 2005 no longer produce good agreement with the sound speed, convection zone depth, and convection zone helium abundance inferred from solar oscillation data. Attempts to modify the input physics of the standard model, for example, by including enhanced diffusion, increased opacities, accretion, convective overshoot, or gravity waves have not restored the good agreement attained with the prior abundances. Here we present new models including early mass loss via a stronger solar wind. Early mass loss has been investigated prior to the solar abundance problem to deplete lithium and resolve the 'faint early sun problem'. We find that mass loss modifies the core structure and deepens the convection zone, and so improves agreement with oscillation data using the new abundances: however the amount of mass loss must be small to avoid destroying all of the surface lithium, and agreement is not fully restored. We also considered the prospects for increasing solar interior opacities. In order to increase mixture opacities by the 30% required to mitigate the abundance problem, the opacities of individual elements (e.g., O, N, C, and Fe) must be revised by a factor of two to three for solar interior conditions: we are investigating the possibility of broader calculated line wings for bound-bound transitions at the relevant temperatures to enhance opacity. We find that including all of the elements in the AGS05 opacity mixture (through uranium at atomic number Z=92) instead of only the 17 elements in the OPAL opacity mixture increases opacities by a negligible 0.2%.

  14. Discovery of a ternary pseudobrookite phase in the earth-abundant TiZnO

    Office of Scientific and Technical Information (OSTI)

    system (Journal Article) | SciTech Connect Discovery of a ternary pseudobrookite phase in the earth-abundant TiZnO system Citation Details In-Document Search Title: Discovery of a ternary pseudobrookite phase in the earth-abundant TiZnO system Authors: Perry, Nicola H. ; Stevanovic, Vladan ; Lime, Linda Y. ; Mason, Thomas O. [1] ; CSM) [2] ; NWU) [2] ; MIT) [2] + Show Author Affiliations Stanford ( Publication Date: 2016-02-11 OSTI Identifier: 1238274 Resource Type: Journal Article Resource

  15. New Offices, New Ways of Working, and Abundant Energy Savings | Department

    Office of Environmental Management (EM)

    of Energy Offices, New Ways of Working, and Abundant Energy Savings New Offices, New Ways of Working, and Abundant Energy Savings July 6, 2010 - 2:01pm Addthis Allison Casey Senior Communicator, NREL A few weeks ago, our entire communications office was lucky enough to be among the first to move into the new Research Support Facility (RSF) here at the National Renewable Energy Lab (NREL). Moving into a new building may not sound all that exciting, but this was a momentous day for NREL: the

  16. No Confinement Needed: Observation of a Metastable Hydrophobic Wetting Two-Layer Ice on Graphene

    SciTech Connect (OSTI)

    Kimmel, Gregory A.; Matthiesen, Jesper; Baer, Marcel; Mundy, Christopher J.; Petrik, Nikolay G.; Smith, R. Scott; Dohnalek, Zdenek; Kay, Bruce D.

    2009-09-09

    The structure of water at interfaces is crucial for processes ranging from photocatalysis to protein folding. Here, we investigate the structure and lattice dynamics of two-layer crystalline ice films grown on a hydrophobic substrate - graphene on Pt(111) - with low energy electron diffraction, reflection-absorption infrared spectroscopy, rare-gas adsorption/desorption, and ab-initio molecular dynamics. Unlike hexagonal ice, which consists of stacks of puckered hexagonal "bilayers", this new ice polymorph consists of two flat hexagonal sheets of water molecules in which the hexagons in each sheet are stacked directly on top of each other. Such two-layer ices have been predicted for water confined between hydrophobic slits, but not previously observed. Our results show that the two-layer ice forms even at zero pressure at a single hydrophobic interface by maximizing the number of hydrogen bonds at the expense of adopting a non-tetrahedral geometry with weakened bonds.

  17. On the scalability of the Albany/FELIX first-order Stokes approximation ice sheet solver for large-scale simulations of the Greenland and Antarctic ice sheets

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Tezaur, Irina K.; Tuminaro, Raymond S.; Perego, Mauro; Salinger, Andrew G.; Price, Stephen F.

    2015-01-01

    We examine the scalability of the recently developed Albany/FELIX finite-element based code for the first-order Stokes momentum balance equations for ice flow. We focus our analysis on the performance of two possible preconditioners for the iterative solution of the sparse linear systems that arise from the discretization of the governing equations: (1) a preconditioner based on the incomplete LU (ILU) factorization, and (2) a recently-developed algebraic multigrid (AMG) preconditioner, constructed using the idea of semi-coarsening. A strong scalability study on a realistic, high resolution Greenland ice sheet problem reveals that, for a given number of processor cores, the AMG preconditionermore » results in faster linear solve times but the ILU preconditioner exhibits better scalability. A weak scalability study is performed on a realistic, moderate resolution Antarctic ice sheet problem, a substantial fraction of which contains floating ice shelves, making it fundamentally different from the Greenland ice sheet problem. Here, we show that as the problem size increases, the performance of the ILU preconditioner deteriorates whereas the AMG preconditioner maintains scalability. This is because the linear systems are extremely ill-conditioned in the presence of floating ice shelves, and the ill-conditioning has a greater negative effect on the ILU preconditioner than on the AMG preconditioner.« less

  18. Long-range azimuthal correlations in proton-proton and proton-nucleus collisions from the incoherent scattering of partons

    SciTech Connect (OSTI)

    Ma, Guo -Liang; Bzdak, Adam

    2014-11-04

    We show that the incoherent elastic scattering of partons, as present in a multi-phase transport model (AMPT), with a modest partonparton cross-section of ?=1.53 mb?=1.53 mb, naturally explains the long-range two-particle azimuthal correlation as observed in protonproton and protonnucleus collisions at the Large Hadron Collider.

  19. Long-range azimuthal correlations in proton–proton and proton–nucleus collisions from the incoherent scattering of partons

    SciTech Connect (OSTI)

    Ma, Guo -Liang; Bzdak, Adam

    2014-11-04

    In this study, we show that the incoherent elastic scattering of partons, as present in a multi-phase transport model (AMPT), with a modest parton–parton cross-section of σ = 1.5 – 3 mb, naturally explains the long-range two-particle azimuthal correlation as observed in proton–proton and proton–nucleus collisions at the Large Hadron Collider.

  20. Special features of the isospin splitting of the giant dipole resonance in the {sup 90}Zr nucleus

    SciTech Connect (OSTI)

    Varlamov, V. V. Peskov, N. N.; Stepanov, M. E.

    2009-02-15

    Data on the proton and neutron channels of the {sup 90}Zr photodisintegration were analyzed in detail, basic parameters of the isospin splitting of the giant dipole resonance in {sup 90}Zr being determined by the properties of these channels. New data concerning the cross sections for the partial photoneutron reactions {sup 90}Zr({gamma}, n){sup 89}Zr and {sup 90}Zr({gamma}, 2n){sup 88}Zr and resulting from a simultaneous correction of data from experiments performed in Livermore (USA) and Saclay (France) by using beams of quasimonoenergetic annihilation photons were invoked. Use was made of information about the positions on the energy scale of states characterized by different isospin values in the {sup 90}Zr nucleus and nuclei neighboring it, which are members of the respective isospin multiplet. New data on the parameters of the isospin splitting of the giant dipole resonance in the {sup 90}Zr nucleus were obtained on the basis of a global analysis of data on the giant-dipole-resonance states of the {sup 90}Zr nucleus, which are manifested in the respective photoneutron and photoproton cross sections and in their decay channels involving states of different isospin in neighboring nuclei.

  1. Novel two-step laser ablation and ionization mass spectrometry (2S-LAIMS) of actor-spectator ice layers: Probing chemical composition of D{sub 2}O ice beneath a H{sub 2}O ice layer

    SciTech Connect (OSTI)

    Yang, Rui Gudipati, Murthy S.

    2014-03-14

    In this work, we report for the first time successful analysis of organic aromatic analytes imbedded in D{sub 2}O ices by novel infrared (IR) laser ablation of a layered non-absorbing D{sub 2}O ice (spectator) containing the analytes and an ablation-active IR-absorbing H{sub 2}O ice layer (actor) without the analyte. With these studies we have opened up a new method for the in situ analysis of solids containing analytes when covered with an IR laser-absorbing layer that can be resonantly ablated. This soft ejection method takes advantage of the tenability of two-step infrared laser ablation and ultraviolet laser ionization mass spectrometry, previously demonstrated in this lab to study chemical reactions of polycyclic aromatic hydrocarbons (PAHs) in cryogenic ices. The IR laser pulse tuned to resonantly excite only the upper H{sub 2}O ice layer (actor) generates a shockwave upon impact. This shockwave penetrates the lower analyte-containing D{sub 2}O ice layer (spectator, a non-absorbing ice that cannot be ablated directly with the wavelength of the IR laser employed) and is reflected back, ejecting the contents of the D{sub 2}O layer into the vacuum where they are intersected by a UV laser for ionization and detection by a time-of-flight mass spectrometer. Thus, energy is transmitted from the laser-absorbing actor layer into the non-absorbing spectator layer resulting its ablation. We found that isotope cross-contamination between layers was negligible. We also did not see any evidence for thermal or collisional chemistry of PAH molecules with H{sub 2}O molecules in the shockwave. We call this shockwave mediated surface resonance enhanced subsurface ablation technique as two-step laser ablation and ionization mass spectrometry of actor-spectator ice layers. This method has its roots in the well-established MALDI (matrix assisted laser desorption and ionization) method. Our method offers more flexibility to optimize both the processesablation and ionization. This new technique can thus be potentially employed to undertake in situ analysis of materials imbedded in diverse media, such as cryogenic ices, biological samples, tissues, minerals, etc., by covered with an IR-absorbing laser ablation medium and study the chemical composition and reaction pathways of the analyte in its natural surroundings.

  2. Solar Cells from Earth-Abundant Semiconductors with Plasmon-Enhanced Light Absorption

    SciTech Connect (OSTI)

    Atwater, Harry

    2012-04-30

    Progress is reported in these areas: Plasmonic Light Trapping in Thin Film a-Si Solar Cells; Plasmonic Light Trapping in Thin InGaN Quantum Well Solar Cells; and Earth Abundant Cu{sub 2}O and Zn{sub 3}P{sub 2} Solar Cells.

  3. NREL Explores Earth-Abundant Materials for Future Solar Cells (Fact Sheet)

    SciTech Connect (OSTI)

    Not Available

    2012-10-01

    Researchers at the National Renewable Energy Laboratory (NREL) are using a theory-driven technique - sequential cation mutation - to understand the nature and limitations of promising solar cell materials that can replace today's technologies. Finding new materials that use Earth-abundant elements and are easily manufactured is important for large-scale solar electricity deployment.

  4. SODIUM AND OXYGEN ABUNDANCES IN THE OPEN CLUSTER NGC6791 FROM APOGEE H-BAND SPECTROSCOPY

    SciTech Connect (OSTI)

    Cunha, Katia; Souto, Diogo; Smith, Verne V.; Johnson, Jennifer A.; Bergemann, Maria; Mszros, Szabolcs; Shetrone, Matthew D.; Prieto, Carlos Allende; Schiavon, Ricardo P.; Frinchaboy, Peter; Zasowski, Gail; Bizyaev, Dmitry; Holtzman, Jon; Garca Prez, Ana E.; Majewski, Steven R.; Nidever, David; Beers, Timothy; Carrera, Ricardo; Geisler, Doug; Gunn, James; and others

    2015-01-10

    The open cluster NGC6791 is among the oldest, most massive, and metal-rich open clusters in the Galaxy. High-resolution H-band spectra from the Apache Point Observatory Galactic Evolution Experiment (APOGEE) of 11 red giants in NGC6791 are analyzed for their chemical abundances of iron, oxygen, and sodium. The abundances of these three elements are found to be homogeneous (with abundance dispersions at the level of ?0.05-0.07 dex) in these cluster red giants, which span much of the red-giant branch (T {sub eff} ? 3500-4600K), and include two red clump giants. From the infrared spectra, this cluster is confirmed to be among the most metal-rich clusters in the Galaxy (([Fe/H]) = 0.34 0.06) and is found to have a roughly solar value of [O/Fe] and slightly enhanced [Na/Fe]. Our non-LTE calculations for the studied Na I lines in the APOGEE spectral region (16373.86 and 16388.85 ) indicate only small departures from LTE (?0.04 dex) for the parameter range and metallicity of the studied stars. The previously reported double population of cluster members with different Na abundances is not found among the studied sample.

  5. Fingerprints of anomalous primordial Universe on the abundance of large scale structures

    SciTech Connect (OSTI)

    Baghram, Shant; Abolhasani, Ali Akbar; Firouzjahi, Hassan; Namjoo, Mohammad Hossein E-mail: abolhasani@ipm.ir E-mail: MohammadHossein.Namjoo@utdallas.edu

    2014-12-01

    We study the predictions of anomalous inflationary models on the abundance of structures in large scale structure observations. The anomalous features encoded in primordial curvature perturbation power spectrum are (a): localized feature in momentum space, (b): hemispherical asymmetry and (c): statistical anisotropies. We present a model-independent expression relating the number density of structures to the changes in the matter density variance. Models with localized feature can alleviate the tension between observations and numerical simulations of cold dark matter structures on galactic scales as a possible solution to the missing satellite problem. In models with hemispherical asymmetry we show that the abundance of structures becomes asymmetric depending on the direction of observation to sky. In addition, we study the effects of scale-dependent dipole amplitude on the abundance of structures. Using the quasars data and adopting the power-law scaling k{sup n{sub A}-1} for the amplitude of dipole we find the upper bound n{sub A}<0.6 for the spectral index of the dipole asymmetry. In all cases there is a critical mass scale M{sub c} in which for MM{sub c}) the enhancement in variance induced from anomalous feature decreases (increases) the abundance of dark matter structures in Universe.

  6. DISSECTING PHOTOMETRIC REDSHIFT FOR ACTIVE GALACTIC NUCLEUS USING XMM- AND CHANDRA-COSMOS SAMPLES

    SciTech Connect (OSTI)

    Salvato, M.; Hasinger, G.; Ilbert, O.; Rau, A.; Brusa, M.; Bongiorno, A.; Civano, F.; Elvis, M.; Zamorani, G.; Vignali, C.; Comastri, A.; Bardelli, S.; Bolzonella, M.; Cappelluti, N.; Aussel, H.; Le Floc'h, E.; Mainieri, V.; Capak, P.; Caputi, K.; and others

    2011-12-01

    In this paper, we release accurate photometric redshifts for 1692 counterparts to Chandra sources in the central square degree of the Cosmic Evolution Survey (COSMOS) field. The availability of a large training set of spectroscopic redshifts that extends to faint magnitudes enabled photometric redshifts comparable to the highest quality results presently available for normal galaxies. We demonstrate that morphologically extended, faint X-ray sources without optical variability are more accurately described by a library of normal galaxies (corrected for emission lines) than by active galactic nucleus (AGN) dominated templates, even if these sources have AGN-like X-ray luminosities. Preselecting the library on the bases of the source properties allowed us to reach an accuracy {sigma}{sub {Delta}z/(1+z{sub s{sub p{sub e{sub c)}}}}}{approx}0.015 with a fraction of outliers of 5.8% for the entire Chandra-COSMOS sample. In addition, we release revised photometric redshifts for the 1735 optical counterparts of the XMM-detected sources over the entire 2 deg{sup 2} of COSMOS. For 248 sources, our updated photometric redshift differs from the previous release by {Delta}z > 0.2. These changes are predominantly due to the inclusion of newly available deep H-band photometry (H{sub AB} = 24 mag). We illustrate once again the importance of a spectroscopic training sample and how an assumption about the nature of a source together, with the number and the depth of the available bands, influences the accuracy of the photometric redshifts determined for AGN. These considerations should be kept in mind when defining the observational strategies of upcoming large surveys targeting AGNs, such as eROSITA at X-ray energies and the Australian Square Kilometre Array Pathfinder Evolutionary Map of the Universe in the radio band.

  7. Q2122-444: A NAKED ACTIVE GALACTIC NUCLEUS FULLY DRESSED

    SciTech Connect (OSTI)

    Gliozzi, M.; Satyapal, S.; Panessa, F.; Franca, F. La; Saviane, I.; Monaco, L.; Foschini, L.; Kedziora-Chudczer, L.; Sambruna, R. M.

    2010-12-20

    Based on previous spectral and temporal optical studies, Q2122-444 has been classified as a naked active galactic nucleus (AGN) or true type 2 AGN, that is, an AGN that genuinely lacks a broad-line region (BLR). Its optical spectrum seemed to possess only narrow forbidden emission lines that are typical of type 2 (obscured) AGNs, but the long-term optical light curve, obtained from a monitoring campaign over more than two decades, showed strong variability, apparently ruling out the presence of heavy obscuration. Here we present the results from a {approx}40 ks XMM-Newton observation of Q2122-444 carried out to shed light on the energetics of this enigmatic AGN. The X-ray analysis was complemented with Australia Telescope Compact Array radio data to assess the possible presence of a jet, and with new NTT/EFOSC2 optical spectroscopic data to verify the actual absence of a BLR. The higher-quality optical data revealed the presence of strong and broad Balmer lines that are at odds with the previous spectral classification of this AGN. The lack of detection of radio emission rules out the presence of a jet. The X-ray data combined with simultaneous UV observations carried out by the Optical Monitor (OM) aboard XMM-Newton confirm that Q2122-444 is a typical type 1 AGN without any significant intrinsic absorption. New estimates of the black hole mass independently obtained from the broad Balmer lines and from a new scaling technique based on X-ray spectral data suggest that Q2122-444 is accreting at a relatively high rate in Eddington units.

  8. AN OUTFLOW PERPENDICULAR TO THE RADIO JET IN THE SEYFERT NUCLEUS OF NGC5929

    SciTech Connect (OSTI)

    Riffel, Rogemar A.; Storchi-Bergmann, Thaisa; Riffel, Rogrio E-mail: thaisa@ufrgs.br

    2014-01-10

    We report the observation of an outflow perpendicular to the radio jet in near-infrared integral field spectra of the inner 250pc of the Seyfert2 galaxy NGC5929. The observations were obtained with the Gemini Near-infrared Integral Field Spectrograph at a spatial resolution of ?20pc and spectral resolution of R ? 5300 and reveal a region ?50pc wide crossing the nucleus and extending by ?300pc perpendicularly to the known radio jet in this galaxy. Along this structurewhich we call the south-east-north-west (SE-NW) stripthe emission line profiles show two velocity components, one blueshifted and the other redshifted by 150km s{sup 1} and 150km s{sup 1}, respectively, relative to the systemic velocity. We interpret these two components as being due to an outflow perpendicular to the radio jet, which is supported by low-frequency radio emission observed along the same region. We attribute this feature to the interaction of ambient gas with an ''equatorial outflow'' predicted in recent accretion disk and torus wind models. Perpendicularly to the SE-NW strip, thus approximately along the radio jet, single-component profiles show blueshifts of ? 150km s{sup 1} to the north-east and similar redshifts to the south-west, which can be attributed to gas counter-rotating relative to the stellar kinematics. More double-peaked profiles are observed in association with the two radio hot spots, attributed to interaction of the radio jet with the surrounding gas.

  9. ISOTROPIC HEATING OF GALAXY CLUSTER CORES VIA RAPIDLY REORIENTING ACTIVE GALACTIC NUCLEUS JETS

    SciTech Connect (OSTI)

    Babul, Arif; Sharma, Prateek; Reynolds, Christopher S.

    2013-05-01

    Active galactic nucleus (AGN) jets carry more than sufficient energy to stave off catastrophic cooling of the intracluster medium (ICM) in the cores of cool-core clusters. However, in order to prevent catastrophic cooling, the ICM must be heated in a near-isotropic fashion and narrow bipolar jets with P{sub jet} = 10{sup 44-45} erg s{sup -1}, typical of radio AGNs at cluster centers, are inefficient in heating the gas in the transverse direction to the jets. We argue that due to existent conditions in cluster cores, the supermassive black holes (SMBHs) will, in addition to accreting gas via radiatively inefficient flows, experience short stochastic episodes of enhanced accretion via thin disks. In general, the orientation of these accretion disks will be misaligned with the spin axis of the black holes (BHs) and the ensuing torques will cause the BH's spin axis (and therefore the jet axis) to slew and rapidly change direction. This model not only explains recent observations showing successive generations of jet-lobes-bubbles in individual cool-core clusters that are offset from each other in the angular direction with respect to the cluster center, but also shows that AGN jets can heat the cluster core nearly isotropically on the gas cooling timescale. Our model does require that the SMBHs at the centers of cool-core clusters be spinning relatively slowly. Torques from individual misaligned disks are ineffective at tilting rapidly spinning BHs by more than a few degrees. Additionally, since SMBHs that host thin accretion disks will manifest as quasars, we predict that roughly 1-2 rich clusters within z < 0.5 should have quasars at their centers.

  10. Toward construction of the unified lepton-nucleus interaction model from a few hundred MeV to GeV region

    SciTech Connect (OSTI)

    Nakamura, S. X.; Hayato, Y.; Hirai, M.; Saito, K.; Kamano, H.; Kumano, S.; Sakuda, M.; Sato, T.

    2015-05-15

    Next generation neutrino oscillation experiments will need a quantitative understanding of neutrino-nucleus interaction far better than ever. Kinematics covered by the relevant neutrino-nucleus interaction spans wide region, from the quasi-elastic, through the resonance region, to the deeply inelastic scattering region. The neutrino-nucleus interaction in each region has quite different characteristics. Obviously, it is essential to combine different expertise to construct a unified model that covers all the kinematical region of the neutrino-nucleus interaction. Recently, several experimentalists and theorists got together to form a collaboration to tackle this problem. In this contribution, we report the collaborations recent activity and a goal in near future.

  11. Development of an ultrasonic pulse-echo (UPE) technique for aircraft icing studies

    SciTech Connect (OSTI)

    Liu, Yang; Hu, Hui [Department of Aerospace Engineering, Iowa State University, 2271 Howe Hall, Room 1200, Ames, IA 50011 (United States); Chen, Wen-Li [Department of Aerospace Engineering, Iowa State University, 2271 Howe Hall, Room 1200, Ames, IA 50011 (United States); School of Civil Engineering, Harbin Institute of Technology, Harbin, Heilongjiang 150090 (China); Bond, Leonard J. [Department of Aerospace Engineering, Iowa State University, 2271 Howe Hall, Room 1200, Ames, IA 50011 (United States); Center for Nondestructive Evaluation, Iowa State University, 1915 Scholl Road, 151 ASC II, Ames, IA 50011 (United States)

    2014-02-18

    Aircraft operating in some cold weather conditions face the risk of icing. Icing poses a threat to flight safety and its management is expensive. Removing light frost on a clear day from a medium-size business jet can cost $300, heavy wet snow removal can cost $3,000 and removal of accumulated frozen/freezing rain can cost close to $10,000. Understanding conditions that lead to severe icing events is important and challenging. When an aircraft or rotorcraft flies in a cold climate, some of the super cooled droplets impinging on exposed aircraft surfaces may flow along the surface prior to freezing and give various forms and shapes of ice. The runback behavior of a water film on an aircraft affects the morphology of ice accretion and the rate of formation. In this study, we report the recent progress to develop an Ultrasonic Pulse-Echo (UPE) technique to provide real-time thickness distribution measurements of surface water flows driven by boundary layer airflows for aircraft icing studies. A series of initial experimental investigations are conducted in an ice wind tunnel employing an array of ultrasonic transducers placed underneath the surface of a flat plate. The water runback behavior on the plate is evaluated by measuring the thickness profile variation of the water film along the surface by using the UPE technique under various wind speed and flow rate conditions.

  12. Seismicity on the western Greenland Ice Sheet: Surface fracture in the vicinity of active moulins

    SciTech Connect (OSTI)

    Carmichael, Joshua D.; Joughin, Ian; Behn, Mark D.; Das, Sarah; King, Matt A.; Stevens, Laura; Lizarralde, Dan

    2015-06-25

    We analyzed geophone and GPS measurements collected within the ablation zone of the western Greenland Ice Sheet during a ~35 day period of the 2011 melt season to study changes in ice deformation before, during, and after a supraglacial lake drainage event. During rapid lake drainage, ice flow speeds increased to ~400% of winter values, and icequake activity peaked. At times >7 days after drainage, this seismicity developed variability over both diurnal and longer periods (~10 days), while coincident ice speeds fell to ~150% of winter values and showed nightly peaks in spatial variability. Approximately 95% of all detected seismicity in the lake basin and its immediate vicinity was triggered by fracture propagation within near-surface ice (<330 m deep) that generated Rayleigh waves. Icequakes occurring before and during drainage frequently were collocated with the down flow (west) end of the primary hydrofracture through which the lake drained but shifted farther west and outside the lake basin after the drainage. We interpret these results to reveal vertical hydrofracture opening and local uplift during the drainage, followed by enhanced seismicity and ice flow on the downstream side of the lake basin. This region collocates with interferometric synthetic aperture radar-measured speedup in previous years and could reflect the migration path of the meltwater supplied to the bed by the lake. The diurnal seismic signal can be associated with nightly reductions in surface melt input that increase effective basal pressure and traction, thereby promoting elevated strain in the surficial ice.

  13. Modeling the impediment of methane ebullition bubbles by seasonal lake ice

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Greene, S.; Walter Anthony, K. M.; Archer, D.; Sepulveda-Jauregui, A.; Martinez-Cruz, K.

    2014-12-08

    Microbial methane (CH4) ebullition (bubbling) from anoxic lake sediments comprises a globally significant flux to the atmosphere, but ebullition bubbles in temperate and polar lakes can be trapped by winter ice cover and later released during spring thaw. This "ice-bubble storage" (IBS) constitutes a novel mode of CH4 emission. Before bubbles are encapsulated by downward-growing ice, some of their CH4 dissolves into the lake water, where it may be subject to oxidation. We present field characterization and a model of the annual CH4 cycle in Goldstream Lake, a thermokarst (thaw) lake in interior Alaska. We find that summertime ebullition dominatesmore » annual CH4 emissions to the atmosphere. Eighty percent of CH4 in bubbles trapped by ice dissolves into the lake water column in winter, and about half of that is oxidized. The ice growth rate and the magnitude of the CH4 ebullition flux are important controlling factors of bubble dissolution. Seven percent of annual ebullition CH4 is trapped as IBS and later emitted as ice melts. In a future warmer climate, there will likely be less seasonal ice cover, less IBS, less CH4 dissolution from trapped bubbles, and greater CH4 emissions from northern lakes.« less

  14. Modeling the impediment of methane ebullition bubbles by seasonal lake ice

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Greene, S.; Walter Anthony, K. M.; Archer, D.; Sepulveda-Jauregui, A.; Martinez-Cruz, K.

    2014-07-15

    Microbial methane (CH4) ebullition (bubbling) from anoxic lake sediments comprises a globally significant flux to the atmosphere, but ebullition bubbles in temperate and polar lakes can be trapped by winter ice cover and later released during spring thaw. This "ice-bubble storage" (IBS) constitutes a novel mode of CH4 emission. Before bubbles are encapsulated by downward-growing ice, some of their CH4 dissolves into the lake water, where it may be subject to oxidation. We present field characterization and a model of the annual CH4 cycle in Goldstream Lake, a thermokarst (thaw) lake in interior Alaska. We find that summertime ebullition dominatesmore » annual CH4 emissions to the atmosphere. Eighty percent of CH4 in bubbles trapped by ice dissolves into the lake water column in winter, and about half of that is oxidized. The ice growth rate and the magnitude of the CH4 ebullition flux are important controlling factors of bubble dissolution. Seven percent of annual ebullition CH4 is trapped as IBS and later emitted as ice melts. In a future warmer climate, there will likely be less seasonal ice cover, less IBS, less CH4 dissolution from trapped bubbles, and greater CH4 emissions from northern lakes.« less

  15. Laboratory studies of oil spill behavior in broken ice fields. Final report Nov 80-Nov 81

    SciTech Connect (OSTI)

    Free, A.P.; Cox, J.C.; Schultz, L.A.

    1981-10-01

    This study examined the short-term behavior of oil spilled in or near a field of broken ice. The mechanics of oil seeping through the spaces between the ice blocks were examined, both on the level of a single straight gap and on the level of a random broken ice field, through experiments performed in ARCTEC, Incorporated's Ice Flume. The spreading of oil due to movement of the ice pack is discussed. The effects of the environment in the spill area, especially currents and winds, are taken into account throughout the study. The report gives information which permits the determination of the one-dimensional spread rate of oil spilled in a broken ice field, such as might be encountered in a natural lead or in a ship channel. The results are presented as a set of recommendations for use in oil spill response planning or for use by on-site response personnel in predicting the behavior of oil spilled in broken ice fields.

  16. Understanding Ice Supersaturation, Particle Growth, and Number Concentration in Cirrus Clouds

    SciTech Connect (OSTI)

    Comstock, Jennifer M.; Lin, Ruei-Fong; Starr, David O.; Yang, P.

    2008-12-10

    Many factors control the ice supersaturation and microphysical properties in cirrus clouds. We explore the effects of dynamic forcing, ice nucleation mechanisms, and ice crystal growth rate on the evolution and distribution of water vapor and cloud properties in cirrus clouds using a detailed microphysical model and remote sensing measurements obtained at the Department of Energys Atmospheric Radiation Measurement (ARM) Climate Research Facility located near Lamont, OK. To help understand dynamic scales important in cirrus formation, we force the model using both large-scale forcing derived using ARM variational analysis, and mean mesoscale velocity derived from radar Doppler velocity measurements. Both heterogeneous and homogeneous nucleation processes are explored, where we have implemented a rigorous classical theory heterogeneous nucleation scheme to compare with empirical representations. We evaluate model simulations by examining both bulk cloud properties and distributions of measured radar reflectivity, lidar extinction, and water vapor profiles, as well as retrieved cloud microphysical properties. This approach allows for independent verification of both the large and small particle modes of the particle size distribution. Our results suggest that mesoscale variability is the primary mechanism needed to reproduce observed quantities, while nucleation mechanism is secondary. Slow ice crystal growth tends to overestimate the number of small ice crystals, but does not seem to influence bulk properties such as ice water path and cloud thickness. The most realistic simulations as compared with observations are forced using mesoscale waves, include fast ice crystal growth, and initiate ice by either homogeneous or heterogeneous nucleation. Ice crystal number concentrations on the order of 10-100 L-1 produce results consistent with both lidar and radar observations during a cirrus event observed on 7 December 1999, which has an optical depth range typical of midlatitude cirrus.

  17. Changes in the firn structure of the western Greenland Ice Sheet caused by recent warming

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    de la Peña, S.; Howat, I. M.; Nienow, P. W.; van den Broeke, M. R.; Mosley-Thompson, E.; Price, S. F.; Mair, D.; Noël, B.; Sole, A. J.

    2015-06-11

    Atmospheric warming over the Greenland Ice Sheet during the last 2 decades has increased the amount of surface meltwater production, resulting in the migration of melt and percolation regimes to higher altitudes and an increase in the amount of ice content from refrozen meltwater found in the firn above the superimposed ice zone. Here we present field and airborne radar observations of buried ice layers within the near-surface (0–20 m) firn in western Greenland, obtained from campaigns between 1998 and 2014. We find a sharp increase in firn-ice content in the form of thick widespread layers in the percolation zone,more » which decreases the capacity of the firn to store meltwater. The estimated total annual ice content retained in the near-surface firn in areas with positive surface mass balance west of the ice divide in Greenland reached a maximum of 74 ± 25 Gt in 2012, compared to the 1958–1999 average of 13 ± 2 Gt, while the percolation zone area more than doubled between 2003 and 2012. Increased melt and column densification resulted in surface lowering averaging –0.80 ± 0.39 m yr⁻¹ between 1800 and 2800 m in the accumulation zone of western Greenland. Since 2007, modeled annual melt and refreezing rates in the percolation zone at elevations below 2100 m surpass the annual snowfall from the previous year, implying that mass gain in the region is retained after melt in the form of refrozen meltwater. If current melt trends over high elevation regions continue, subsequent changes in firn structure will have implications for the hydrology of the ice sheet and related abrupt seasonal densification could become increasingly significant for altimetry-derived ice sheet mass balance estimates.« less

  18. Evaluating and Constraining Ice Cloud Parameterizations in CAM5 using Aircraft Measurements from the SPARTICUS Campaign

    SciTech Connect (OSTI)

    Zhang, Kai; Liu, Xiaohong; Wang, Minghuai; Comstock, Jennifer M.; Mitchell, David; Mishra, Subhashree; Mace, Gerald G.

    2013-01-01

    This study uses aircraft measurements of relative humidity and ice crystal size distribution collected in synoptic cirrus during the SPARTICUS (Small PARTicles In CirrUS) field campaign to evaluate and constrain ice cloud parameterizations in the Community Atmosphere Model version 5. The probability density function (PDF) of ice crystal number concentration (Ni) derived from high frequency (1 Hz) measurements features a strong dependence on ambient temperature. As temperature decreases from -35C to -62C, the peak in the PDF shifts from 10-20 L-1 to 200-1000 L-1, while the ice crystal number concentration shows a factor of 6-7 increase. Model simulations are performed with two different insitu ice nucleation schemes. One of the schemes can reproduce a clear increase of Ni with decreasing temperature, by using either an observation based ice nuclei spectrum or a classical theory based spectrum with a relatively low (5%-10%) maximum freezing ratio for dust aerosols. The simulation with the other scheme, which assumes a high maximum freezing ratio (100%), shows much weaker temperature dependence of Ni. Simulations are also performed to test empirical parameters related to water vapor deposition and the auto-conversion of ice crystals to snow. Results show that a value between 0.05 and 0.1 for the water vapor deposition coefficient and 250 um for the critical ice crystal size can produce good agreements between model simulation and the SPARTICUS measurements in terms of ice crystal number concentration and effective radius. The climate impact of perturbing these parameters is also discussed.

  19. A Nano Surface Icephobic Coating Delays Ice Formation | GE Global Research

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Nano Surface Icephobic Coating Delays Ice Formation Click to email this to a friend (Opens in new window) Share on Facebook (Opens in new window) Click to share (Opens in new window) Click to share on LinkedIn (Opens in new window) Click to share on Tumblr (Opens in new window) A Nano Surface Icephobic Coating Delays Ice Formation Azar Alizadeh 2012.03.08 Hi folks, As many of you may know ice could be a huge problem in everyday life. For many of us who live in the North East of the US, dealing

  20. Progress on MPAS Land Ice Model Development (Conference) | SciTech Connect

    Office of Scientific and Technical Information (OSTI)

    on MPAS Land Ice Model Development Citation Details In-Document Search Title: Progress on MPAS Land Ice Model Development Authors: Hoffman, Matthew J. [1] + Show Author Affiliations Los Alamos National Laboratory [Los Alamos National Laboratory Publication Date: 2014-02-04 OSTI Identifier: 1119586 Report Number(s): LA-UR-14-20657 DOE Contract Number: AC52-06NA25396 Resource Type: Conference Resource Relation: Conference: CESM Land Ice Working Group Meeting ; 2014-01-30 - 2014-01-31 ; Boulder,

  1. Fast proton hopping detection in ice I{sub h} by quasi-elastic neutron

    Office of Scientific and Technical Information (OSTI)

    scattering. (Journal Article) | SciTech Connect Fast proton hopping detection in ice I{sub h} by quasi-elastic neutron scattering. Citation Details In-Document Search Title: Fast proton hopping detection in ice I{sub h} by quasi-elastic neutron scattering. Quasi-elastic neutron scattering was employed on samples of HCl-doped polycrystalline ice I{sub h}. The analysis of the scattering signal provides the excess proton hopping time, {tau}{sub hop}, in the temperature range of 140-195 K. The

  2. Meltwater effects on flow of Greenland's ice sheet less severe for sea

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    level rise than earlier feared, scientists say Side effects of increasing meltwater less severe than feared Meltwater effects on flow of Greenland's ice sheet less severe for sea level rise than earlier feared, scientists say The team found that accelerating ice sheet movement from increasing meltwater lubrication is likely to have only a minor role in future sea-level rise. August 19, 2013 A stream of meltwater on the surface of the Greenland Ice Sheet enters a moulin connecting to the

  3. Meltwater effects on flow of Greenland's ice sheet less severe for sea

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    level rise than earlier feared, scientists say Side effects of increasing meltwater less severe than feared Meltwater effects on flow of Greenland's ice sheet less severe for sea level rise than earlier feared, scientists say The team found that accelerating ice sheet movement from increasing meltwater lubrication is likely to have only a minor role in future sea-level rise. August 19, 2013 A stream of meltwater on the surface of the Greenland Ice Sheet enters a moulin connecting to the

  4. Laboratory Investigation of Contact Freezing and the Aerosol to Ice Crystal Transformation Process

    SciTech Connect (OSTI)

    Shaw, Raymond A.

    2014-10-28

    This project has been focused on the following objectives: 1. Investigations of the physical processes governing immersion versus contact nucleation, specifically surface-induced crystallization; 2. Development of a quadrupole particle trap with full thermodynamic control over the temperature range 0 to 40 C and precisely controlled water vapor saturation ratios for continuous, single-particle measurement of the aerosol to ice crystal transformation process for realistic ice nuclei; 3. Understanding the role of ice nucleation in determining the microphysical properties of mixed-phase clouds, within a framework that allows bridging between laboratory and field measurements.

  5. On the Equivalence of Trapped Colloids, Pinned Vortices, and Spin Ice

    SciTech Connect (OSTI)

    Nisoli, Cristiano

    2014-04-23

    We investigate the recently reported analogies between pinned vortices in nano-structured superconductors or colloids in optical traps, and spin ice materials. The frustration of the two models, one describing colloids and vortices, the other describing spin ice, differs essentially. However, their effective energetics is made identical by the contribution of an emergent field associated to a topological charge. This equivalence extends to the local low-energy dynamics of the ice manifold, yet breaks down in lattices of mixed coordination, because of topological charge transfer between sub-latices.

  6. Update on Greenland Ice Sheet Simulations In CISM and CESM (Conference) |

    Office of Scientific and Technical Information (OSTI)

    SciTech Connect Update on Greenland Ice Sheet Simulations In CISM and CESM Citation Details In-Document Search Title: Update on Greenland Ice Sheet Simulations In CISM and CESM Authors: Lipscomb, William Henry [1] + Show Author Affiliations Los Alamos National Laboratory Publication Date: 2016-02-12 OSTI Identifier: 1238137 Report Number(s): LA-UR-16-20919 DOE Contract Number: AC52-06NA25396 Resource Type: Conference Resource Relation: Conference: Land Ice Working Group Meeting ; 2016-02-09

  7. STATEMENT OF WORK (SOW) TEMPLATE COMBINED EIR/ICE SUPPORT CONTRACTOR

    Energy Savers [EERE]

    COMBINED EIR/ICE SUPPORT CONTRACTOR The template presented below is a Statement of Work (SOW) for services of an EIR/ICE Support Contractor for assisting OECM in conducting a combined EIR/ICE at CD-2. Project and review specific information should be incorporated. Explanatory text appears in italics, while information that should be selected appears in <<brackets>>. The format and contents of this SOW is not compulsory, and the use is at the discretion of the OECM Analysts, tailored

  8. Laboratory determination of the infrared band strengths of pyrene frozen in water ice: Implications for the composition of interstellar ices

    SciTech Connect (OSTI)

    Hardegree-Ullman, E. E.; Gudipati, M. S.; Werner, M.; Boogert, A. C. A.; Lignell, H.; Allamandola, L. J.; Stapelfeldt, K. R. E-mail: gudipati@jpl.nasa.gov

    2014-04-01

    Broad infrared emission features (e.g., at 3.3, 6.2, 7.7, 8.6, and 11.3 ?m) from the gas phase interstellar medium have long been attributed to polycyclic aromatic hydrocarbons (PAHs). A significant portion (10%-20%) of the Milky Way's carbon reservoir is locked in PAH molecules, which makes their characterization integral to our understanding of astrochemistry. In molecular clouds and the dense envelopes and disks of young stellar objects (YSOs), PAHs are expected to be frozen in the icy mantles of dust grains where they should reveal themselves through infrared absorption. To facilitate the search for frozen interstellar PAHs, laboratory experiments were conducted to determine the positions and strengths of the bands of pyrene mixed with H{sub 2}O and D{sub 2}O ices. The D{sub 2}O mixtures are used to measure pyrene bands that are masked by the strong bands of H{sub 2}O, leading to the first laboratory determination of the band strength for the CH stretching mode of pyrene in water ice near 3.25 ?m. Our infrared band strengths were normalized to experimentally determined ultraviolet band strengths, and we find that they are generally ?50% larger than those reported by Bouwman et al. based on theoretical strengths. These improved band strengths were used to reexamine YSO spectra published by Boogert et al. to estimate the contribution of frozen PAHs to absorption in the 5-8 ?m spectral region, taking into account the strength of the 3.25 ?m CH stretching mode. It is found that frozen neutral PAHs contain 5%-9% of the cosmic carbon budget and account for 2%-9% of the unidentified absorption in the 5-8 ?m region.

  9. Impact of individual nuclear masses on r-process abundances

    SciTech Connect (OSTI)

    Mumpower, M. R.; Surman, R.; Fang, D. -L.; Beard, M.; Möller, P.; Kawano, T.; Aprahamian, A.

    2015-09-15

    We have performed for the first time a comprehensive study of the sensitivity of r-process nucleosynthesis to individual nuclear masses across the chart of nuclides. Using the latest version (2012) of the Finite-Range Droplet Model, we consider mass variations of ±0.5 MeV and propagate each mass change to all affected quantities, including Q values, reaction rates, and branching ratios. We find such mass variations can result in up to an order of magnitude local change in the final abundance pattern produced in an r-process simulation. As a result, we identify key nuclei whose masses have a substantial impact on abundance predictions for hot, cold, and neutron star merger r-process scenarios and could be measured at future radioactive beam facilities.

  10. ELEMENTAL ABUNDANCES IN THE EJECTA OF OLD CLASSICAL NOVAE FROM LATE-EPOCH SPITZER SPECTRA

    SciTech Connect (OSTI)

    Helton, L. Andrew; Vacca, William D.; Gehrz, Robert D.; Woodward, Charles E.; Shenoy, Dinesh P.; Wagner, R. Mark; Evans, Aneurin; Krautter, Joachim; Schwarz, Greg J.; Starrfield, Sumner

    2012-08-10

    We present Spitzer Space Telescope mid-infrared IRS spectra, supplemented by ground-based optical observations, of the classical novae V1974 Cyg, V382 Vel, and V1494 Aql more than 11, 8, and 4 years after outburst, respectively. The spectra are dominated by forbidden emission from neon and oxygen, though in some cases, there are weak signatures of magnesium, sulfur, and argon. We investigate the geometry and distribution of the late time ejecta by examination of the emission line profiles. Using nebular analysis in the low-density regime, we estimate lower limits on the abundances in these novae. In V1974 Cyg and V382 Vel, our observations confirm the abundance estimates presented by other authors and support the claims that these eruptions occurred on ONe white dwarfs (WDs). We report the first detection of neon emission in V1494 Aql and show that the system most likely contains a CO WD.

  11. VOLATILE TRANSPORT INSIDE SUPER-EARTHS BY ENTRAPMENT IN THE WATER-ICE MATRIX

    SciTech Connect (OSTI)

    Levi, A.; Podolak, M.; Sasselov, D.

    2013-05-20

    Whether volatiles can be entrapped in a background matrix composing planetary envelopes and be dragged via convection to the surface is a key question in understanding atmospheric fluxes, cycles, and composition. In this paper, we consider super-Earths with an extensive water mantle (i.e., water planets), and the possibility of entrapment of methane in their extensive water-ice envelopes. We adopt the theory developed by van der Waals and Platteeuw for modeling solid solutions, often used for modeling clathrate hydrates, and modify it in order to estimate the thermodynamic stability field of a new phase called methane filled ice Ih. We find that in comparison to water ice VII the filled ice Ih structure may be stable not only at the high pressures but also at the high temperatures expected at the core-water mantle transition boundary of water planets.

  12. Webinar: Energy Conservation Standards for Automatic Commercial Ice Makers; Notice of Public Meeting

    Broader source: Energy.gov [DOE]

    DOE is conducting a public meeting and webinar for the notice of public meeting regarding energy conservation standards for automatic commercial ice makers. For more information, please visit the...

  13. Predicting Land-Ice Retreat and Sea-Level Rise with the Community...

    Office of Scientific and Technical Information (OSTI)

    Recent studies suggest a potential large contribution (approx0.5 mcentury) from the marine-based West Antarctic Ice Sheet, linked to changes in Southern Ocean wind stress. To ...

  14. Weakening of the Stratospheric Polar Vortex by Arctic Sea-Ice Loss

    SciTech Connect (OSTI)

    Kim, Baek-Min; Son, Seok-Woo; Min, Seung-Ki; Jeong, Jee-Hoon; Kim, Seong-Joong; Zhang, Xiangdong; Shim, Taehyoun; Yoon, Jin-Ho

    2014-09-02

    Successive cold winters of severely low temperatures in recent years have had critical social and economic impacts on the mid-latitude continents in the Northern Hemisphere. Although these cold winters are thought to be partly driven by dramatic losses of Arctic sea ice, the mechanism that links sea ice loss to cold winters remains a subject of debate. Here, by conducting observational analyses and model experiments, we show how Arctic sea ice loss and cold winters in extra-polar regions are dynamically connected through the polar stratosphere. We find that decreased sea ice cover during early winter months (November-December), especially over the Barents-Kara seas, enhance the upward propagation of planetary-scale waves with wavenumbers of 1 and 2, subsequently weakening the stratospheric polar vortex in mid-winter (January- February). The weakened polar vortex preferentially induces a negative phase of Arctic Oscillation at the surface, resulting in low temperatures in mid-latitudes.

  15. Progress on an ARM/GCSS/SPARC TWP-ICE Monsoon Case Study

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Progress on an ARMGCSSSPARC TWP-ICE Monsoon Case Study Ann Fridlind and Andrew Ackerman ann.fridlind@nasa.gov * www.giss.nasa.govfridlind Introduction Source: Lori Chappel,...

  16. Impact of heterogeneous ice nuclei on homogeneous freezing events in cirrus clouds

    SciTech Connect (OSTI)

    Spichtinger, Peter; Cziczo, Daniel J.

    2010-07-29

    The influence of initial heterogeneous nucleation on subsequent homogeneous nucleation events in cirrus clouds is investigated using a box model which includes the explicit impact of aerosols on the nucleation of ice crystals and sedimentation. Different effects are discussed, namely the impact of external mixtures of heterogeneous ice nuclei and the influence of size-dependent freezing thresholds. Several idealized experiments are carried out, which show that the treatment of external mixtures of ice nuclei can strongly change later homogeneous nucleation events (i.e., the ice crystal number densities) in different matters. The use of size-dependent freezing thresholds can also change the cloud prop erties when compared to more simple parameterizations. This size effect is most important for large IN concentrations. Based upon these findings, recommendations for future modeling and measurement efforts are presented.

  17. Predicting Land-Ice Retreat and Sea-Level Rise with the Community...

    Office of Scientific and Technical Information (OSTI)

    Recent studies suggest a potential large contribution (approx0.5 mcentury) from the marine-based West Antarctic Ice Sheet, linked to changes in Southern Ocean wind stress. To...

  18. Multidimensional metrics for estimating phage abundance, distribution, gene density, and sequence coverage in metagenomes

    SciTech Connect (OSTI)

    Aziz, Ramy K.; Dwivedi, Bhakti; Akhter, Sajia; Breitbart, Mya; Edwards, Robert A.

    2015-05-08

    Phages are the most abundant biological entities on Earth and play major ecological roles, yet the current sequenced phage genomes do not adequately represent their diversity, and little is known about the abundance and distribution of these sequenced genomes in nature. Although the study of phage ecology has benefited tremendously from the emergence of metagenomic sequencing, a systematic survey of phage genes and genomes in various ecosystems is still lacking, and fundamental questions about phage biology, lifestyle, and ecology remain unanswered. To address these questions and improve comparative analysis of phages in different metagenomes, we screened a core set of publicly available metagenomic samples for sequences related to completely sequenced phages using the web tool, Phage Eco-Locator. We then adopted and deployed an array of mathematical and statistical metrics for a multidimensional estimation of the abundance and distribution of phage genes and genomes in various ecosystems. Experiments using those metrics individually showed their usefulness in emphasizing the pervasive, yet uneven, distribution of known phage sequences in environmental metagenomes. Using these metrics in combination allowed us to resolve phage genomes into clusters that correlated with their genotypes and taxonomic classes as well as their ecological properties. By adding this set of metrics to current metaviromic analysis pipelines, where they can provide insight regarding phage mosaicism, habitat specificity, and evolution.

  19. Natural abundance 17O DNP two-dimensional and surface-enhanced NMR spectroscopy

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Perras, Frédéric A.; Kobayashi, Takeshi; Pruski, Marek

    2015-06-22

    Due to its extremely low natural abundance and quadrupolar nature, the 17O nuclide is very rarely used for spectroscopic investigation of solids by NMR without isotope enrichment. Additionally, the applicability of dynamic nuclear polarization (DNP), which leads to sensitivity enhancements of 2 orders of magnitude, to 17O is wrought with challenges due to the lack of spin diffusion and low polarization transfer efficiency from 1H. Here, we demonstrate new DNP-based measurements that extend 17O solid-state NMR beyond its current capabilities. The use of the PRESTO technique instead of conventional 1H–17O cross-polarization greatly improves the sensitivity and enables the facile measurementmore » of undistorted line shapes and two-dimensional 1H–17O HETCOR NMR spectra as well as accurate internuclear distance measurements at natural abundance. This was applied for distinguishing hydrogen-bonded and lone 17O sites on the surface of silica gel; the one-dimensional spectrum of which could not be used to extract such detail. As a result, this greatly enhanced sensitivity has enabled, for the first time, the detection of surface hydroxyl sites on mesoporous silica at natural abundance, thereby extending the concept of DNP surface-enhanced NMR spectroscopy to the 17O nuclide.« less

  20. Multidimensional metrics for estimating phage abundance, distribution, gene density, and sequence coverage in metagenomes

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Aziz, Ramy K.; Dwivedi, Bhakti; Akhter, Sajia; Breitbart, Mya; Edwards, Robert A.

    2015-05-08

    Phages are the most abundant biological entities on Earth and play major ecological roles, yet the current sequenced phage genomes do not adequately represent their diversity, and little is known about the abundance and distribution of these sequenced genomes in nature. Although the study of phage ecology has benefited tremendously from the emergence of metagenomic sequencing, a systematic survey of phage genes and genomes in various ecosystems is still lacking, and fundamental questions about phage biology, lifestyle, and ecology remain unanswered. To address these questions and improve comparative analysis of phages in different metagenomes, we screened a core set ofmore » publicly available metagenomic samples for sequences related to completely sequenced phages using the web tool, Phage Eco-Locator. We then adopted and deployed an array of mathematical and statistical metrics for a multidimensional estimation of the abundance and distribution of phage genes and genomes in various ecosystems. Experiments using those metrics individually showed their usefulness in emphasizing the pervasive, yet uneven, distribution of known phage sequences in environmental metagenomes. Using these metrics in combination allowed us to resolve phage genomes into clusters that correlated with their genotypes and taxonomic classes as well as their ecological properties. By adding this set of metrics to current metaviromic analysis pipelines, where they can provide insight regarding phage mosaicism, habitat specificity, and evolution.« less

  1. Impacts of ocean albedo alteration on Arctic sea ice restoration and Northern Hemisphere climate

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Cvijanovic, Ivana; Caldeira, Ken; MacMartin, Douglas G.

    2015-04-01

    The Arctic Ocean is expected to transition into a seasonally ice-free state by mid-century, enhancing Arctic warming and leading to substantial ecological and socio-economic challenges across the Arctic region. It has been proposed that artificially increasing high latitude ocean albedo could restore sea ice, but the climate impacts of such a strategy have not been previously explored. Motivated by this, we investigate the impacts of idealized high latitude ocean albedo changes on Arctic sea ice restoration and climate. In our simulated 4xCO₂ climate, imposing surface albedo alterations over the Arctic Ocean leads to partial sea ice recovery and a modestmore » reduction in Arctic warming. With the most extreme ocean albedo changes, imposed over the area 70°–90°N, September sea ice cover stabilizes at ~40% of its preindustrial value (compared to ~3% without imposed albedo modifications). This is accompanied by an annual mean Arctic surface temperature decrease of ~2 °C but no substantial global mean temperature decrease. Imposed albedo changes and sea ice recovery alter climate outside the Arctic region too, affecting precipitation distribution over parts of the continental United States and Northeastern Pacific. For example, following sea ice recovery, wetter and milder winter conditions are present in the Southwest United States while the East Coast experiences cooling. We conclude that although ocean albedo alteration could lead to some sea ice recovery, it does not appear to be an effective way of offsetting the overall effects of CO₂ induced global warming.« less

  2. Heating Profiles Derived From Cm-wavelength Radar During TWP-ICE

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Heating Profiles Derived From Cm-wavelength Radar During TWP-ICE Heating Profiles Derived From Cm-wavelength Radar During TWP-ICE Courtney Schumacher and Kaycee Frederick Courtney Schumacher and Kaycee Frederick Department of Atmospheric Sciences Department of Atmospheric Sciences Texas A&M University Texas A&M University LATENT HEATING ESTIMATES PRELIMINARY RADIATIVE HEATING ESTIMATES Shallow (< 8km) convection Deep convection Stratiform rain SC 4% SC 37% SC 11% SF 24% SF 9% SF 8% DC

  3. On the Development & Performance of a First Order Stokes Finite Element Ice

    Office of Scientific and Technical Information (OSTI)

    Sheet Dycore Built Using Trilinos Software Components. (Conference) | SciTech Connect Conference: On the Development & Performance of a First Order Stokes Finite Element Ice Sheet Dycore Built Using Trilinos Software Components. Citation Details In-Document Search Title: On the Development & Performance of a First Order Stokes Finite Element Ice Sheet Dycore Built Using Trilinos Software Components. Abstract not provided. Authors: Tezaur, Irina Kalashnikova ; Salinger, Andrew G. ;

  4. Hydrogen Materials Compatibility for the H-ICE | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    0 DOE Vehicle Technologies and Hydrogen Programs Annual Merit Review and Peer Evaluation Meeting, June 7-11, 2010 -- Washington D.C. PDF icon pm019_pitman_2010_p.pdf More Documents & Publications Hydrogen Materials Compatibility for the H-ICE Hydrogen Material Compatibility for Hydrogen ICE Vehicle Technologies Office Merit Review 2014: Design Optimization of Piezoceramic Multilayer Actuators for Heavy Duty Diesel Engine Fuel Injectors

  5. FELIX: advances in modeling forward and inverse ice-sheet problems.

    Office of Scientific and Technical Information (OSTI)

    (Conference) | SciTech Connect FELIX: advances in modeling forward and inverse ice-sheet problems. Citation Details In-Document Search Title: FELIX: advances in modeling forward and inverse ice-sheet problems. Abstract not provided. Authors: Salinger, Andrew G. ; Perego, Mauro ; Hoffman, Mattew ; Leng, Wei ; Gunzburger, Max ; Price, Stephen ; Stadler, Georg ; Ju, Lili Publication Date: 2013-02-01 OSTI Identifier: 1115922 Report Number(s): SAND2013-1519C 479955 DOE Contract Number:

  6. optimal initial conditions for coupling ice sheet models to earth system

    Office of Scientific and Technical Information (OSTI)

    models (Conference) | SciTech Connect Conference: optimal initial conditions for coupling ice sheet models to earth system models Citation Details In-Document Search Title: optimal initial conditions for coupling ice sheet models to earth system models × You are accessing a document from the Department of Energy's (DOE) SciTech Connect. This site is a product of DOE's Office of Scientific and Technical Information (OSTI) and is provided as a public service. Visit OSTI to utilize additional

  7. Building a next-generation community ice sheet model: meeting summary

    Office of Scientific and Technical Information (OSTI)

    (Journal Article) | SciTech Connect Journal Article: Building a next-generation community ice sheet model: meeting summary Citation Details In-Document Search Title: Building a next-generation community ice sheet model: meeting summary No abstract prepared. Authors: Lipscomb, William [1] ; Price, Stephen [1] ; Bueler, Ed [2] ; Holland, David [3] ; Johnson, Jesse [4] + Show Author Affiliations Los Alamos National Laboratory UNIV OF ALASKA NEW YORK UNIV UNIV OF MONTANA Publication Date:

  8. Building a next-generation community ice sheet model: meeting summary

    Office of Scientific and Technical Information (OSTI)

    (Journal Article) | SciTech Connect Journal Article: Building a next-generation community ice sheet model: meeting summary Citation Details In-Document Search Title: Building a next-generation community ice sheet model: meeting summary × You are accessing a document from the Department of Energy's (DOE) SciTech Connect. This site is a product of DOE's Office of Scientific and Technical Information (OSTI) and is provided as a public service. Visit OSTI to utilize additional information

  9. Moving loads on sea ice: A juxtaposition of theory and experiment

    SciTech Connect (OSTI)

    Rayner, G.D.; Enlow, R.L.; Squire, V.A.; Robinson, W.H.

    1994-12-31

    New in situ experimental data relating to strains induced by the ground effect of overflying aircraft and vehicles operating on an ice sheet are examined alongside the sophisticated theoretical predictions of Strathdee et al. (1991). The dataset is very complete, allowing directional features as well as the magnitude of the induced strain field to be determined and compared with theory. Results have a direct application to safe operating criteria for dynamic loading of ice plates.

  10. optimal initial conditions for coupling ice sheet models to earth system

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    models (Conference) | SciTech Connect Conference: optimal initial conditions for coupling ice sheet models to earth system models Citation Details In-Document Search Title: optimal initial conditions for coupling ice sheet models to earth system models Authors: Perego, Mauro [1] ; Price, Stephen F. Dr [2] ; Stadler, Georg [3] + Show Author Affiliations Sandia National Laboratories [Sandia National Laboratories Los Alamos National Laboratory [Los Alamos National Laboratory Institute for

  11. Determination of 3-D Cloud Ice Water Contents by Combining Multiple Data

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Sources from Satellite, Ground Radar, and a Numerical Model Determination of 3-D Cloud Ice Water Contents by Combining Multiple Data Sources from Satellite, Ground Radar, and a Numerical Model Liu, Guosheng Florida State University Seo, Eun-Kyoung Florida State University Category: Cloud Properties This study aims at determining the 3-dimensional distribution of ice water content over a broad area near the Atmospheric Radiation Measurement Southern Great Plain site, where cloud radar and

  12. Determination of Ice Water Path Over the ARM SGP Using Combined Surface and Satellite Datasets

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Determination of Ice Water Path Over the ARM SGP Using Combined Surface and Satellite Datasets J. Huang, M. M. Khaiyer, and P. W. Heck Analytical Services & Materials, Inc. Hampton, Virginia P. Minnis and B. Lin Atmospheric Sciences National Aeronautics and Space Administration Langley Research Center Hampton, Virginia T.-F. Fan Science Applications International Corporation Hampton, Virginia Introduction Global information of cloud ice water path (IWP) is urgently needed for testing of

  13. Determining Cloud Ice Water Path from High-Frequency Microwave Measurements

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Determining Cloud Ice Water Path from High-Frequency Microwave Measurements G. Liu Department of Meteorology Florida State University Tallahassee, Florida Introduction A better understanding of cloud water content and its large-scale distribution is important to climate research for improving our ability to parameterize and validate cloud/precipitation processes in global climate models. The goal of this study is to determine the distribution and large-scale advection of cloud ice/liquid water

  14. Inside Ice Under High Pressure | U.S. DOE Office of Science (SC)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Inside Ice Under High Pressure Basic Energy Sciences (BES) BES Home About Research Facilities Science Highlights Benefits of BES Funding Opportunities Basic Energy Sciences Advisory Committee (BESAC) Community Resources Contact Information Basic Energy Sciences U.S. Department of Energy SC-22/Germantown Building 1000 Independence Ave., SW Washington, DC 20585 P: (301) 903-3081 F: (301) 903-6594 E: Email Us More Information » 10.01.14 Inside Ice Under High Pressure New insights from neutron

  15. Impacts of ocean albedo alteration on Arctic sea ice restoration and Northern Hemisphere climate

    SciTech Connect (OSTI)

    Cvijanovic, Ivana; Caldeira, Ken; MacMartin, Douglas G.

    2015-04-01

    The Arctic Ocean is expected to transition into a seasonally ice-free state by mid-century, enhancing Arctic warming and leading to substantial ecological and socio-economic challenges across the Arctic region. It has been proposed that artificially increasing high latitude ocean albedo could restore sea ice, but the climate impacts of such a strategy have not been previously explored. Motivated by this, we investigate the impacts of idealized high latitude ocean albedo changes on Arctic sea ice restoration and climate. In our simulated 4xCO₂ climate, imposing surface albedo alterations over the Arctic Ocean leads to partial sea ice recovery and a modest reduction in Arctic warming. With the most extreme ocean albedo changes, imposed over the area 70°–90°N, September sea ice cover stabilizes at ~40% of its preindustrial value (compared to ~3% without imposed albedo modifications). This is accompanied by an annual mean Arctic surface temperature decrease of ~2 °C but no substantial global mean temperature decrease. Imposed albedo changes and sea ice recovery alter climate outside the Arctic region too, affecting precipitation distribution over parts of the continental United States and Northeastern Pacific. For example, following sea ice recovery, wetter and milder winter conditions are present in the Southwest United States while the East Coast experiences cooling. We conclude that although ocean albedo alteration could lead to some sea ice recovery, it does not appear to be an effective way of offsetting the overall effects of CO₂ induced global warming.

  16. Comprehensive {gamma}-ray spectroscopy of rotational bands in the N=Z+1 nucleus {sup 61}Zn

    SciTech Connect (OSTI)

    Andersson, L.-L.; Rudolph, D.; Johansson, E. K.; Andreoiu, C.; Ekman, J.; Fahlander, C.; Rietz, R. du; Ragnarsson, I.; Torres, D. A.; Carpenter, M. P.; Seweryniak, D.; Zhu, S.; Charity, R. J.; Chiara, C. J.; Hoel, C.; Reviol, W.; Sarantites, D. G.; Sobotka, L. G.; Pechenaya, O. L.

    2009-02-15

    The {sub 30}{sup 61}Zn{sub 31} nucleus has been studied via the combined data of two fusion-evaporation reaction experiments using a {sup 36}Ar beam and a {sup 28}Si target foil. The experimental setups involved the Ge array GAMMASPHERE and neutron and charged particle detectors placed around the target position. The resulting level scheme comprises about 120 excited states connected via some 180 {gamma}-ray transitions. In total, seven rotational structures were identified up to I{approx}25 or higher and compared with predictions from cranked Nilsson-Strutinsky calculations.

  17. AGB sodium abundances in the globular cluster 47 Tucanae (NGC 104)

    SciTech Connect (OSTI)

    Johnson, Christian I.; McDonald, Iain; Zijlstra, Albert A. E-mail: iain.mcdonald-2@manchester.ac.uk; and others

    2015-02-01

    A recent analysis comparing the [Na/Fe] distributions of red giant branch (RGB) and asymptotic giant branch (AGB) stars in the Galactic globular cluster NGC 6752 found that the ratio of Na-poor to Na-rich stars changes from 30:70 on the RGB to 100:0 on the AGB. The surprising paucity of Na-rich stars on the AGB in NGC 6752 warrants additional investigations to determine if the failure of a significant fraction of stars to ascend the AGB is an attribute common to all globular clusters. Therefore, we present radial velocities, [Fe/H], and [Na/Fe] abundances for 35 AGB stars in the Galactic globular cluster 47 Tucanae (47 Tuc; NGC 104), and compare the AGB [Na/Fe] distribution with a similar RGB sample published previously. The abundances and velocities were derived from high-resolution spectra obtained with the Michigan/Magellan Fiber System and MSpec spectrograph on the MagellanClay 6.5 m telescope. We find the average heliocentric radial velocity and [Fe/H] values to be ?RV{sub helio.}? = ?18.56 km s{sup ?1} (? = 10.21 km s{sup ?1}) and ?[Fe/H]? = ?0.68 (? = 0.08), respectively, in agreement with previous literature estimates. The average [Na/Fe] abundance is 0.12 dex lower in the 47 Tuc AGB sample compared to the RGB sample, and the ratio of Na-poor to Na-rich stars is 63:37 on the AGB and 45:55 on the RGB. However, in contrast to NGC 6752, the two 47 Tuc populations have nearly identical [Na/Fe] dispersion and interquartile range values. The data presented here suggest that only a small fraction (?20%) of Na-rich stars in 47 Tuc may fail to ascend the AGB, which is a similar result to that observed in M13. Regardless of the cause for the lower average [Na/Fe] abundance in AGB stars, we find that Na-poor stars and at least some Na-rich stars in 47 Tuc evolve through the early AGB phase. The contrasting behavior of Na-rich stars in 47 Tuc and NGC 6752 suggests that the RGB [Na/Fe] abundance alone is insufficient for predicting if a star will ascend the AGB.

  18. Importance of aerosol composition, mixing state, and morphology for heterogeneous ice nucleation: A combined field and laboratory approach

    SciTech Connect (OSTI)

    Baustian, Kelly J.; Cziczo, Daniel J.; Wise, M. A.; Pratt, Kerri; Kulkarni, Gourihar R.; Hallar, Anna G.; Tolbert, Margaret A.

    2012-03-30

    In this study chemical compositions of background aerosol and ice nuclei were examined through laboratory investigations using Raman spectroscopy and field measurements by single-particle mass spectrometry. Aerosol sampling took place at Storm Peak Laboratory in Steamboat Springs, Colorado (elevation of 3210 m). A cascade impactor was used to collect coarse-mode aerosol particles for laboratory analysis by Raman spectroscopy; the composition, mixing state, and heterogeneous ice nucleation activity of individual particles were examined. For in situ analysis of fine-mode aerosol, ice nucleation on ambient particles was observed using a compact ice nucleation chamber. Ice crystals were separated from unactivated aerosol using a pumped counterflow virtual impactor, and ice nuclei were analyzed using particle analysis by laser mass spectrometry. For both fine and coarse modes, the ice nucleating particle fractions were enriched in minerals and depleted in sulfates and nitrates, compared to the background aerosol sampled. The vast majority of particles in both the ambient and ice active aerosol fractions contained a detectable amount of organic material. Raman spectroscopy showed that organic material is sometimes present in the form of a coating on the surface of inorganic particles. We find that some organic-containing particles serve as efficient ice nuclei while others do not. For coarse-mode aerosol, organic particles were only observed to initiate ice formation when oxygen signatures were also present in their spectra.

  19. Black carbon aerosols and the third polar ice cap

    SciTech Connect (OSTI)

    Menon, Surabi; Koch, Dorothy; Beig, Gufran; Sahu, Saroj; Fasullo, John; Orlikowski, Daniel

    2010-04-15

    Recent thinning of glaciers over the Himalayas (sometimes referred to as the third polar region) have raised concern on future water supplies since these glaciers supply water to large river systems that support millions of people inhabiting the surrounding areas. Black carbon (BC) aerosols, released from incomplete combustion, have been increasingly implicated as causing large changes in the hydrology and radiative forcing over Asia and its deposition on snow is thought to increase snow melt. In India BC emissions from biofuel combustion is highly prevalent and compared to other regions, BC aerosol amounts are high. Here, we quantify the impact of BC aerosols on snow cover and precipitation from 1990 to 2010 over the Indian subcontinental region using two different BC emission inventories. New estimates indicate that Indian BC emissions from coal and biofuel are large and transport is expected to expand rapidly in coming years. We show that over the Himalayas, from 1990 to 2000, simulated snow/ice cover decreases by {approx}0.9% due to aerosols. The contribution of the enhanced Indian BC to this decline is {approx}36%, similar to that simulated for 2000 to 2010. Spatial patterns of modeled changes in snow cover and precipitation are similar to observations (from 1990 to 2000), and are mainly obtained with the newer BC estimates.

  20. DETAILED ABUNDANCES OF TWO VERY METAL-POOR STARS IN DWARF GALAXIES

    SciTech Connect (OSTI)

    Kirby, Evan N.; Cohen, Judith G.

    2012-12-01

    The most metal-poor stars in dwarf spheroidal galaxies (dSphs) can show the nucleosynthetic patterns of one or a few supernovae (SNe). These SNe could have zero metallicity, making metal-poor dSph stars the closest surviving links to Population III stars. Metal-poor dSph stars also help to reveal the formation mechanism of the Milky Way (MW) halo. We present the detailed abundances from Keck/HIRES spectroscopy for two very metal-poor stars in two MW dSphs. One star, in the Sculptor dSph, has [Fe I/H] = -2.40. The other star, in the Ursa Minor dSph, has [Fe I/H] = -3.16. Both stars fall in the previously discovered low-metallicity, high-[{alpha}/Fe] plateau. Most abundance ratios of very metal-poor stars in these two dSphs are largely consistent with very metal-poor halo stars. However, the abundances of Na and some r-process elements lie at the lower end of the envelope defined by inner halo stars of similar metallicity. We propose that the metallicity dependence of SN yields is the cause. The earliest SNe in low-mass dSphs have less gas to pollute than the earliest SNe in massive halo progenitors. As a result, dSph stars at -3 < [Fe/H] < -2 sample SNe with [Fe/H] << -3, whereas halo stars in the same metallicity range sample SNe with [Fe/H] {approx} -3. Consequently, enhancements in [Na/Fe] and [r/Fe] were deferred to higher metallicity in dSphs than in the progenitors of the inner halo.

  1. ORIGIN OF THE UNUSUALLY LOW NITROGEN ABUNDANCES IN YOUNG POPULATIONS OF THE LARGE MAGELLANIC CLOUD

    SciTech Connect (OSTI)

    Bekki, Kenji [ICRAR, M468, University of Western Australia, 35 Stirling Highway, Crawley Western Australia 6009 (Australia); Tsujimoto, Takuji [National Astronomical Observatory, Mitaka-shi, Tokyo 181-8588 (Japan)

    2010-10-01

    It is a longstanding problem that H II regions and very young stellar populations in the Large Magellanic Cloud (LMC) have nitrogen abundances ([N/H]) that are a factor of {approx}7 lower than the solar value. We here discuss a new scenario in which the observed unusually low nitrogen abundances can be closely associated with recent collisions and subsequent accretion of H I high velocity clouds (HVCs) that surround the Galaxy and have low nitrogen abundances. We show that if the observed low [N/H] is limited to very young stars with ages less than {approx}10{sup 7} yr, then the collision/accretion rate of the HVCs onto the LMC needs to be {approx}0.2 M{sub sun} yr{sup -1} (corresponding to the total HVC mass of 10{sup 6}-10{sup 7} M{sub sun}) to dilute the original interstellar medium (ISM) before star formation. The required accretion rate means that even if the typical mass of HVCs accreted onto the LMC is {approx}10{sup 7} M{sub sun}, the Galaxy needs to have {approx}2500 massive HVCs within the LMC's orbital radius with respect to the Galactic center. The rather large number of required massive HVCs drives us to suggest that the HVCs are not likely to efficiently dilute the ISM of the LMC and consequently lower the [N/H]. We thus suggest the transfer of gas with low [N/H] from the Small Magellanic Cloud to the LMC as a promising scenario that can explain the observed low [N/H].

  2. Light, alpha, and Fe-peak element abundances in the galactic bulge

    SciTech Connect (OSTI)

    Johnson, Christian I.; Rich, R. Michael; Kobayashi, Chiaki; Kunder, Andrea; Koch, Andreas E-mail: rmr@astro.ucla.edu E-mail: akunder@aip.de

    2014-10-01

    We present radial velocities and chemical abundances of O, Na, Mg, Al, Si, Ca, Cr, Fe, Co, Ni, and Cu for a sample of 156 red giant branch stars in two Galactic bulge fields centered near (l, b) = (+5.25,3.02) and (0,12). The (+5.25,3.02) field also includes observations of the bulge globular cluster NGC 6553. The results are based on high-resolution (R ? 20,000), high signal-to-noise ration (S/N ? 70) FLAMES-GIRAFFE spectra obtained through the European Southern Observatory archive. However, we only selected a subset of the original observations that included spectra with both high S/N and that did not show strong TiO absorption bands. This work extends previous analyses of this data set beyond Fe and the ?-elements Mg, Si, Ca, and Ti. While we find reasonable agreement with past work, the data presented here indicate that the bulge may exhibit a different chemical composition than the local thick disk, especially at [Fe/H] ? 0.5. In particular, the bulge [?/Fe] ratios may remain enhanced to a slightly higher [Fe/H] than the thick disk, and the Fe-peak elements Co, Ni, and Cu appear enhanced compared to the disk. There is also some evidence that the [Na/Fe] (but not [Al/Fe]) trends between the bulge and local disk may be different at low and high metallicity. We also find that the velocity dispersion decreases as a function of increasing [Fe/H] for both fields, and do not detect any significant cold, high-velocity populations. A comparison with chemical enrichment models indicates that a significant fraction of hypernovae may be required to explain the bulge abundance trends, and that initial mass functions that are steep, top-heavy (and do not include strong outflow), or truncated to avoid including contributions from stars >40 M {sub ?} are ruled out, in particular because of disagreement with the Fe-peak abundance data. For most elements, the NGC 6553 stars exhibit abundance trends nearly identical to comparable metallicity bulge field stars. However, the star-to-star scatter and mean [Na/Fe] ratios appear higher in the cluster, perhaps indicating additional self-enrichment.

  3. Seismicity on the western Greenland Ice Sheet: Surface fracture in the vicinity of active moulins

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Carmichael, Joshua D.; Joughin, Ian; Behn, Mark D.; Das, Sarah; King, Matt A.; Stevens, Laura; Lizarralde, Dan

    2015-06-25

    We analyzed geophone and GPS measurements collected within the ablation zone of the western Greenland Ice Sheet during a ~35 day period of the 2011 melt season to study changes in ice deformation before, during, and after a supraglacial lake drainage event. During rapid lake drainage, ice flow speeds increased to ~400% of winter values, and icequake activity peaked. At times >7 days after drainage, this seismicity developed variability over both diurnal and longer periods (~10 days), while coincident ice speeds fell to ~150% of winter values and showed nightly peaks in spatial variability. Approximately 95% of all detected seismicitymore » in the lake basin and its immediate vicinity was triggered by fracture propagation within near-surface ice (<330 m deep) that generated Rayleigh waves. Icequakes occurring before and during drainage frequently were collocated with the down flow (west) end of the primary hydrofracture through which the lake drained but shifted farther west and outside the lake basin after the drainage. We interpret these results to reveal vertical hydrofracture opening and local uplift during the drainage, followed by enhanced seismicity and ice flow on the downstream side of the lake basin. This region collocates with interferometric synthetic aperture radar-measured speedup in previous years and could reflect the migration path of the meltwater supplied to the bed by the lake. The diurnal seismic signal can be associated with nightly reductions in surface melt input that increase effective basal pressure and traction, thereby promoting elevated strain in the surficial ice.« less

  4. Influence of surface morphology on the immersion mode ice nucleation efficiency of hematite particles

    SciTech Connect (OSTI)

    Hiranuma, Naruki; Hoffmann, Nadine; Kiselev, Alexei; Dreyer, Axel; Zhang, Kai; Kulkarni, Gourihar R.; Koop, Thomas; Mohler, Ottmar

    2014-03-05

    In this paper, the effect of the morphological modification of aerosol particles with respect to heterogeneous ice nucleation is comprehensively investigated for laboratory-generated hematite particles as a model substrate for atmospheric dust particles. The surface area-scaled ice nucleation efficiencies of monodisperse cubic hematite particles and milled hematite particles were measured with a series of expansion cooling experiments using the Aerosol Interaction and Dynamics in the Atmosphere (AIDA) cloud simulation chamber. Complementary off-line characterization of physico-chemical properties of both hematite subsets were also carried out with scanning electron microscopy (SEM), energy dispersive X-ray (EDX) spectroscopy, dynamic light scattering (DLS), and an electro-kinetical particle charge detector to further constrain droplet-freezing measurements of hematite particles. Additionally, an empirical parameterization derived from our laboratory measurements was implemented in the single-column version of the Community Atmospheric Model version 5 (CAM5) to investigate the model sensitivity in simulated ice crystal number concentration on different ice nucleation efficiencies. From an experimental perspective, our results show that the immersion mode ice nucleation efficiency of milled hematite particles is almost an order of magnitude higher at -35.2 ?C < T < -33.5 ?C than that of the cubic hematite particles, indicating a substantial effect of morphological irregularities on immersion mode freezing. Our modeling results similarly show that the increased droplet-freezing rates of milled hematite particles lead to about one order magnitude higher ice crystal number in the upper troposphere than cubic hematite particles. Overall, our results suggest that the surface irregularities and associated active sites lead to greater ice activation through droplet-freezing.

  5. The IceCube Collaboration:contributions to the 30 th International Cosmic Ray Conference (ICRC 2007),

    SciTech Connect (OSTI)

    IceCube Collaboration; Ackermann, M.

    2007-11-02

    This paper bundles 40 contributions by the IceCube collaboration that were submitted to the 30th International Cosmic Ray Conference ICRC 2007. The articles cover studies on cosmic rays and atmospheric neutrinos, searches for non-localized, extraterrestrial {nu}{sub e}, {nu}{sub {mu}} and {nu}{sub {tau}} signals, scans for steady and intermittent neutrino point sources, searches for dark matter candidates, magnetic monopoles and other exotic particles, improvements in analysis techniques, as well as future detector extensions. The IceCube observatory will be finalized in 2011 to form a cubic-kilometer ice-Cherenkov detector at the location of the geographic South Pole. At the present state of construction, IceCube consists of 52 paired IceTop surface tanks and 22 IceCube strings with a total of 1426 Digital Optical Modules deployed at depths up to 2350 m. The observatory also integrates the 19 string AMANDA subdetector, that was completed in 2000 and extends IceCube's reach to lower energies. Before the deployment of IceTop, cosmic air showers were registered with the 30 station SPASE-2 surface array. IceCube's low noise Digital Optical Modules are very reliable, show a uniform response and record waveforms of arriving photons that are resolvable with nanosecond precision over a large dynamic range. Data acquisition, reconstruction and simulation software are running in production mode and the analyses, profiting from the improved data quality and increased overall sensitivity, are well under way.

  6. H-ATLAS: THE COSMIC ABUNDANCE OF DUST FROM THE FAR-INFRARED BACKGROUND POWER SPECTRUM

    SciTech Connect (OSTI)

    Thacker, Cameron; Cooray, Asantha; Smidt, Joseph; De Bernardis, Francesco; Mitchell-Wynne, K.; Amblard, A.; Auld, R.; Eales, S.; Pascale, E.; Baes, M.; Michalowski, M. J.; Clements, D. L.; Dariush, A.; Hopwood, R.; De Zotti, G.; Dunne, L.; Maddox, S.; Hoyos, C.; Ibar, E.; Jarvis, M.; and others

    2013-05-01

    We present a measurement of the angular power spectrum of the cosmic far-infrared background (CFIRB) anisotropies in one of the extragalactic fields of the Herschel Astrophysical Terahertz Large Area Survey at 250, 350, and 500 {mu}m bands. Consistent with recent measurements of the CFIRB power spectrum in Herschel-SPIRE maps, we confirm the existence of a clear one-halo term of galaxy clustering on arcminute angular scales with large-scale two-halo term of clustering at 30 arcmin to angular scales of a few degrees. The power spectrum at the largest angular scales, especially at 250 {mu}m, is contaminated by the Galactic cirrus. The angular power spectrum is modeled using a conditional luminosity function approach to describe the spatial distribution of unresolved galaxies that make up the bulk of the CFIRB. Integrating over the dusty galaxy population responsible for the background anisotropies, we find that the cosmic abundance of dust, relative to the critical density, to be between {Omega}{sub dust} = 10{sup -6} and 8 Multiplication-Sign 10{sup -6} in the redshift range z {approx} 0-3. This dust abundance is consistent with estimates of the dust content in the universe using quasar reddening and magnification measurements in the Sloan Digital Sky Survey.

  7. THE DUAL ORIGIN OF STELLAR HALOS. II. CHEMICAL ABUNDANCES AS TRACERS OF FORMATION HISTORY

    SciTech Connect (OSTI)

    Zolotov, Adi; Hogg, David W. [Center for Cosmology and Particle Physics, Department of Physics, New York University, 4 Washington Place, New York, NY 10003 (United States); Willman, Beth [Haverford College, Department of Astronomy, 370 Lancaster Avenue, Haverford, PA 19041 (United States); Brooks, Alyson M. [California Institute of Technology, M/C 350-17, Pasadena, CA 91125 (United States); Governato, Fabio [Department of Astronomy, University of Washington, P.O. Box 351580, Seattle, WA 98195 (United States); Shen, Sijing; Wadsley, James, E-mail: az481@nyu.ed, E-mail: bwillman@haverford.ed [Department of Physics and Astronomy, McMaster University, Hamilton, Ontario L88 4M1 (Canada)

    2010-09-20

    Fully cosmological, high-resolution N-body+smooth particle hydrodynamic simulations are used to investigate the chemical abundance trends of stars in simulated stellar halos as a function of their origin. These simulations employ a physically motivated supernova feedback recipe, as well as metal enrichment, metal cooling, and metal diffusion. As presented in an earlier paper, the simulated galaxies in this study are surrounded by stellar halos whose inner regions contain both stars accreted from satellite galaxies and stars formed in situ in the central regions of the main galaxies and later displaced by mergers into their inner halos. The abundance patterns ([Fe/H] and [O/Fe]) of halo stars located within 10 kpc of a solar-like observer are analyzed. We find that for galaxies which have not experienced a recent major merger, in situ stars at the high [Fe/H] end of the metallicity distribution function are more [{alpha}/Fe]-rich than accreted stars at similar [Fe/H]. This dichotomy in the [O/Fe] of halo stars at a given [Fe/H] results from the different potential wells within which in situ and accreted halo stars form. These results qualitatively match recent observations of local Milky Way halo stars. It may thus be possible for observers to uncover the relative contribution of different physical processes to the formation of stellar halos by observing such trends in the halo populations of the Milky Way and other local L{sup *} galaxies.

  8. Seasonal variation in sea turtle density and abundance in the southeast Florida current and surrounding waters

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Bovery, Caitlin M.; Wyneken, Jeanette

    2015-12-30

    Assessment and management of sea turtle populations is often limited by a lack of available data pertaining to at-sea distributions at appropriate spatial and temporal resolutions. Assessing the spatial and temporal distributions of marine turtles in an open system poses both observational and analytical challenges due to the turtles’ highly migratory nature. Surface counts of marine turtles in waters along the southern part of Florida’s east coast were made in and adjacent to the southeast portion of the Florida Current using standard aerial surveys during 2011 and 2012 to assess their seasonal presence. This area is of particular concern formore » sea turtles as interest increases in offshore energy developments, specifically harnessing the power of the Florida Current. While it is understood that marine turtles use these waters, here we evaluate seasonal variation in sea turtle abundance and density over two years. Density of sea turtles observed within the study area ranged from 0.003 turtles km-2 in the winter of 2011 to 0.064 turtles km-2 in the spring of 2012. As a result, this assessment of marine turtles in the waters off southeast Florida quantifies their in-water abundance across seasons in this area to establish baselines and inform future management strategies of these protected species.« less

  9. Seasonal variation in sea turtle density and abundance in the southeast Florida current and surrounding waters

    SciTech Connect (OSTI)

    Bovery, Caitlin M.; Wyneken, Jeanette

    2015-12-30

    Assessment and management of sea turtle populations is often limited by a lack of available data pertaining to at-sea distributions at appropriate spatial and temporal resolutions. Assessing the spatial and temporal distributions of marine turtles in an open system poses both observational and analytical challenges due to the turtles’ highly migratory nature. Surface counts of marine turtles in waters along the southern part of Florida’s east coast were made in and adjacent to the southeast portion of the Florida Current using standard aerial surveys during 2011 and 2012 to assess their seasonal presence. This area is of particular concern for sea turtles as interest increases in offshore energy developments, specifically harnessing the power of the Florida Current. While it is understood that marine turtles use these waters, here we evaluate seasonal variation in sea turtle abundance and density over two years. Density of sea turtles observed within the study area ranged from 0.003 turtles km-2 in the winter of 2011 to 0.064 turtles km-2 in the spring of 2012. As a result, this assessment of marine turtles in the waters off southeast Florida quantifies their in-water abundance across seasons in this area to establish baselines and inform future management strategies of these protected species.

  10. The solar wind neon abundance observed with ACE/SWICS and ULYSSES/SWICS

    SciTech Connect (OSTI)

    Shearer, Paul; Raines, Jim M.; Lepri, Susan T.; Thomas, Jonathan W.; Gilbert, Jason A.; Landi, Enrico; Zurbuchen, Thomas H.; Von Steiger, Rudolf

    2014-07-01

    Using in situ ion spectrometry data from ACE/SWICS, we determine the solar wind Ne/O elemental abundance ratio and examine its dependence on wind speed and evolution with the solar cycle. We find that Ne/O is inversely correlated with wind speed, is nearly constant in the fast wind, and correlates strongly with solar activity in the slow wind. In fast wind streams with speeds above 600 km s{sup 1}, we find Ne/O = 0.10 0.02, in good agreement with the extensive polar observations by Ulysses/SWICS. In slow wind streams with speeds below 400 km s{sup 1}, Ne/O ranges from a low of 0.12 0.02 at solar maximum to a high of 0.17 0.03 at solar minimum. These measurements place new and significant empirical constraints on the fractionation mechanisms governing solar wind composition and have implications for the coronal and photospheric abundances of neon and oxygen. The results are made possible by a new data analysis method that robustly identifies rare elements in the measured ion spectra. The method is also applied to Ulysses/SWICS data, which confirms the ACE observations and extends our view of solar wind neon into the three-dimensional heliosphere.

  11. Laser desorption time-of-flight mass spectrometry of ultraviolet photo-processed ices

    SciTech Connect (OSTI)

    Paardekooper, D. M. Bossa, J.-B.; Isokoski, K.; Linnartz, H.

    2014-10-01

    A new ultra-high vacuum experiment is described that allows studying photo-induced chemical processes in interstellar ice analogues. MATRICES - a Mass Analytical Tool to study Reactions in Interstellar ICES applies a new concept by combining laser desorption and time-of-flight mass spectrometry with the ultimate goal to characterize in situ and in real time the solid state evolution of organic compounds upon UV photolysis for astronomically relevant ice mixtures and temperatures. The performance of the experimental setup is demonstrated by the kinetic analysis of the different photoproducts of pure methane (CH?) ice at 20 K. A quantitative approach provides formation yields of several new species with up to four carbon atoms. Convincing evidence is found for the formation of even larger species. Typical mass resolutions obtained range from M/?M ~320 to ~400 for CH? and argon, respectively. Additional tests show that the typical detection limit (in monolayers) is ?0.02 ML, substantially more sensitive than the regular techniques used to investigate chemical processes in interstellar ices.

  12. An update on modeling land-ice/ocean interactions in CESM

    SciTech Connect (OSTI)

    Asay-davis, Xylar

    2011-01-24

    This talk is an update on ongoing land-ice/ocean coupling work within the Community Earth System Model (CESM). The coupling method is designed to allow simulation of a fully dynamic ice/ocean interface, while requiring minimal modification to the existing ocean model (the Parallel Ocean Program, POP). The method makes use of an immersed boundary method (IBM) to represent the geometry of the ice-ocean interface without requiring that the computational grid be modified in time. We show many of the remaining development challenges that need to be addressed in order to perform global, century long climate runs with fully coupled ocean and ice sheet models. These challenges include moving to a new grid where the computational pole is no longer at the true south pole and several changes to the coupler (the software tool used to communicate between model components) to allow the boundary between land and ocean to vary in time. We discuss benefits for ice/ocean coupling that would be gained from longer-term ocean model development to allow for natural salt fluxes (which conserve both water and salt mass, rather than water volume).

  13. Ice formation in PEM fuel cells operated isothermally at sub-freezing temperatures

    SciTech Connect (OSTI)

    Mukundan, Rangachary; Luhan, Roger W; Davey, John R; Spendelow, Jacob S; Borup, Rodney L; Hussey, Daniel S; Jacobson, David L; Arif, Muhammad

    2009-01-01

    The effect of MEA and GDL structure and composition on the performance of single-PEM fuel cells operated isothermally at subfreezing temperatures is presented. The cell performance and durability are not only dependent on the MEA/GDL materials used but also on their interfaces. When a cell is operated isothermally at sub-freezing temperatures in constant current mode, the water formation due to the current density initially hydrates the membrane/ionomer and then forms ice in the catalyst layer/GDL. An increase in high frequency resistance was also observed in certain MEAs where there is a possibility of ice formation between the catalyst layer and GDL leading to a loss in contact area. The total water/ice holding capacity for any MEA was lower at lower temperatures and higher current densities. The durability of MEAs subjected to multiple isothermal starts was better for LANL prepared MEAs as compared to commercial MEAs, and cloth GDLs when compared to paper GDLs. The ice formation was monitored using high-resolution neutron radiography and was found to be concentrated near the cathode catalyst layer. However, there was significant ice formation in the GDLs especially at the higher temperature ({approx} -10 C) and lower current density (0.02 A/cm{sup 2}) operations. These results are consistent with the longer-term durability observations that show more severe degradation at the lower temperatures.

  14. Benchmarking the x-ray phase contrast imaging for ICF DT ice characterization using roughened surrogates

    SciTech Connect (OSTI)

    Dewald, E; Kozioziemski, B; Moody, J; Koch, J; Mapoles, E; Montesanti, R; Youngblood, K; Letts, S; Nikroo, A; Sater, J; Atherton, J

    2008-06-26

    We use x-ray phase contrast imaging to characterize the inner surface roughness of DT ice layers in capsules planned for future ignition experiments. It is therefore important to quantify how well the x-ray data correlates with the actual ice roughness. We benchmarked the accuracy of our system using surrogates with fabricated roughness characterized with high precision standard techniques. Cylindrical artifacts with azimuthally uniform sinusoidal perturbations with 100 um period and 1 um amplitude demonstrated 0.02 um accuracy limited by the resolution of the imager and the source size of our phase contrast system. Spherical surrogates with random roughness close to that required for the DT ice for a successful ignition experiment were used to correlate the actual surface roughness to that obtained from the x-ray measurements. When comparing average power spectra of individual measurements, the accuracy mode number limits of the x-ray phase contrast system benchmarked against surface characterization performed by Atomic Force Microscopy are 60 and 90 for surrogates smoother and rougher than the required roughness for the ice. These agreement mode number limits are >100 when comparing matching individual measurements. We will discuss the implications for interpreting DT ice roughness data derived from phase-contrast x-ray imaging.

  15. Sensitivity of CAM5-Simulated Arctic Clouds and Radiation to Ice Nucleation Parameterization

    SciTech Connect (OSTI)

    Xie, Shaocheng; Liu, Xiaohong; Zhao, Chuanfeng; Zhang, Yuying

    2013-08-01

    Sensitivity of Arctic clouds and radiation in the Community Atmospheric Model version 5 to the ice nucleation process is examined by testing a new physically based ice nucleation scheme that links the variation of ice nuclei (IN) number concentration to aerosol properties. The default scheme parameterizes the IN concentration simply as a function of ice supersaturation. The new scheme leads to a significant reduction in simulated IN number concentrations at all latitudes while changes in cloud amount and cloud properties are mainly seen in high latitudes and middle latitude storm tracks. In the Arctic, there is a considerable increase in mid-level clouds and a decrease in low clouds, which result from the complex interaction among the cloud macrophysics, microphysics, and the large-scale environment. The smaller IN concentrations result in an increase in liquid water path and a decrease in ice water path due to the slow-down of the Bergeron-Findeisen process in mixed-phase clouds. Overall, there is an increase in the optical depth of Arctic clouds, which leads to a stronger cloud radiative forcing (net cooling) at the top of the atmosphere. The comparison with satellite data shows that the new scheme slightly improves low cloud simulations over most of the Arctic, but produces too many mid-level clouds. Considerable improvements are seen in the simulated low clouds and their properties when compared to Arctic ground-based measurements. Issues with the observations and the model-observation comparison in the Arctic region are discussed.

  16. Research on the Natural Abundance of Deuterium and Other Isotopes in Nature. Final Report for Period Ending September 30, 1958

    DOE R&D Accomplishments [OSTI]

    Urey, H. C.

    1959-10-31

    [Research from September 1957 to 1958 plus a] bibliography, containing about 78 references, on the natural abundance of deuterium and other isotopes in nature is presented. (W.L.H.)

  17. HIGH PRECISION ABUNDANCES OF THE OLD SOLAR TWIN HIP 102152: INSIGHTS ON Li DEPLETION FROM THE OLDEST SUN

    SciTech Connect (OSTI)

    Monroe, TalaWanda R.; Melendez, Jorge; Tucci Maia, Marcelo; Freitas, Fabricio C.; Yong, David; Asplund, Martin; Alves-Brito, Alan; Casagrande, Luca; Bergemann, Maria; Bedell, Megan; Bean, Jacob; Lind, Karin; Castro, Matthieu; Do Nascimento, Jose-Dias; Bazot, Michael

    2013-09-10

    We present the first detailed chemical abundance analysis of the old 8.2 Gyr solar twin, HIP 102152. We derive differential abundances of 21 elements relative to the Sun with precisions as high as 0.004 dex ({approx}<1%), using ultra high-resolution (R = 110,000), high S/N UVES spectra obtained on the 8.2 m Very Large Telescope. Our determined metallicity of HIP 102152 is [Fe/H] = -0.013 {+-} 0.004. The atmospheric parameters of the star were determined to be 54 K cooler than the Sun, 0.09 dex lower in surface gravity, and a microturbulence identical to our derived solar value. Elemental abundance ratios examined versus dust condensation temperature reveal a solar abundance pattern for this star, in contrast to most solar twins. The abundance pattern of HIP 102152 appears to be the most similar to solar of any known solar twin. Abundances of the younger, 2.9 Gyr solar twin, 18 Sco, were also determined from UVES spectra to serve as a comparison for HIP 102152. The solar chemical pattern of HIP 102152 makes it a potential candidate to host terrestrial planets, which is reinforced by the lack of giant planets in its terrestrial planet region. The following non-local thermodynamic equilibrium Li abundances were obtained for HIP 102152, 18 Sco, and the Sun: log {epsilon} (Li) = 0.48 {+-} 0.07, 1.62 {+-} 0.02, and 1.07 {+-} 0.02, respectively. The Li abundance of HIP 102152 is the lowest reported to date for a solar twin, and allows us to consider an emerging, tightly constrained Li-age trend for solar twin stars.

  18. Properties of the 0{sub 2}{sup +} state and isospin excitation in the N=Z nucleus {sup 68}Se

    SciTech Connect (OSTI)

    Al-Khudair, Falih H.; Li, Y. S.; Long, G. L. [Key Laboratory for Quantum Information and Measurements and Department of Physics, Tsinghua University, Beijing 100084 (China); Center of Nuclear Theory, Lanzhou National Laboratory of Accelerators, Lanzhou 730000 (China)

    2007-05-15

    Band structure and electromagnetic transition properties of the low-lying states in the N=Z {sup 68}Se nucleus were studied within the framework of interacting boson model 3. The isospin excitation states with T>T{sub Z} are identified. The M1 and E2 matrix elements for low-lying states have been investigated and were used to identify the low-lying mixed symmetry states. Special attention is given to the occurrence of 0{sub 2}{sup +} state, recently predicted by the projected shell-model (PSM) calculation. The present predicted spectrum for {sup 68}Se is close to the recent PSM results and confirms the results for the 0{sub 2}{sup +} state. The calculated results are compared with available experimental data, and they are in general good agreement.

  19. Competing decay modes of a high-spin isomer in the proton-unbound nucleus ¹⁵⁸Ta*

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Carroll, R. J.; Page, R. D.; Joss, D. T.; Uusitalo, J.; Darby, I. G.; Andgren, K.; Cederwall, B.; Eeckhaudt, S.; Grahn, T.; Gray-Jones, C.; et al

    2015-01-01

    An isomeric state at high spin and excitation energy was recently observed in the proton-unbound nucleus 158Ta. This state was observed to decay by both α and γ decay modes. The large spin change required to decay via γ-ray emission incurs a lifetime long enough for α decay to compete. The α decay has an energy of 8644(11) keV, which is among the highest observed in the region, a partial half-life of 440(70) μs and changes the spin by 11ℏ. In this study, additional evidence supporting the assignment of this α decay to the high-spin isomer in 158Ta will bemore » presented.« less

  20. Impact of Solvent on Photocatalytic Mechanisms: Reactions of Photodesorption Products with Ice Overlayers on the TiO2(110) Surface

    SciTech Connect (OSTI)

    Shen, Mingmin; Henderson, Michael A.

    2011-04-07

    The effects of water and methanol ice overlayers on the photodecomposition of acetone on rutile TiO2(110) were evaluated in ultrahigh vacuum (UHV) using photon stimulated desorption (PSD) and temperature programmed desorption (TPD). In the absence of ice overlayers, acetone photodecomposed on TiO2(110) at 95 K by ejection of a methyl radical into the gas phase and formation of acetate on the surface. With ice overlayers, the methyl radicals are trapped at the interface between TiO2(110) and the ice. When water ice was present, these trapped methyl radicals reacted either with each other to form ethane or with other molecules in the ice (e.g., water or displaced acetone) to form methane (CH4), ethane (CH3CH3) and other products (e.g., methanol), with all of these products trapped in the ice. The new products were free to revisit the surface or depart during desorption of the ice. When methanol ice was present, methane formation came about only from reaction of trapped methyl radicals with the methanol ice. Methane and ethane slowly leaked through methanol ice overlayers into vacuum at 95 K, but not through water ice overlayers. Different degrees of site competition between water and acetone, and between methanol and acetone led to different hydrogen abstraction pathways in the two ices. These results provide new insights into product formation routes and solution-phase radical formation mechanisms that are important in heterogeneous photocatalysis.

  1. Southern Great Plains Ice Nuclei Characterization Experiment Final Campaign Summary

    SciTech Connect (OSTI)

    DeMott, PJ; Suski, KJ; Hill, TCJ; Levin, EJT

    2015-03-01

    The first ever ice nucleating particle (INP) measurements to be collected at the Southern Great Plains site were made during a period from late April to June 2014, as a trial for possible longer-term measurements at the site. These measurements will also be used to lay the foundation for understanding and parameterizing (for cloud resolving modeling) the sources of these climatically important aerosols as well as to augment the existing database containing this knowledge. Siting the measurements during the spring was intended to capture INP sources in or to this region from plant, soil, dust transported over long distances, biomass burning, and pollution aerosols at a time when they may influence warm-season convective clouds and precipitation. Data have been archived of real-time measurements of INP number concentrations as a function of processing conditions (temperature and relative humidity) during 18 days of sampling that spanned two distinctly different weather situations: a warm, dry and windy period with regional dust and biomass burning influences in early May, and a cooler period of frequent precipitation during early June. Precipitation delayed winter wheat harvesting, preventing intended sampling during that perturbation on atmospheric aerosols. INP concentrations were highest and most variable at all temperatures in the dry period, where we attribute the INP activity primarily to soil dust emissions. Additional offline INP analyses are underway to extend the characterization of INP to cover the entire mixed phase cloud regime from -5°C to -35°C during the full study. Initial comparisons between methods on four days show good agreement and excellent future promise. The additional offline immersion freezing data will be archived as soon as completed under separate funding. Analyses of additional specialized studies for specific attribution of INP to biological and smoke sources are continuing via the National Science Foundation and National Aeronautics and Space Administration funding that helped support instrumentation used for the measurements described herein. Aerosol Observing System aerosol data will be vital to the interpretation and parameterization of results as part of analyses for publications in preparation.

  2. CO/H{sub 2} abundance ratio ? 10{sup 4} in a protoplanetary disk

    SciTech Connect (OSTI)

    France, Kevin; McJunkin, Matthew; Herczeg, Gregory J.; Penton, Steven V.

    2014-10-20

    The relative abundances of atomic and molecular species in planet-forming disks around young stars provide important constraints on photochemical disk models and provide a baseline for calculating disk masses from measurements of trace species. A knowledge of absolute abundances, those relative to molecular hydrogen (H{sub 2}), are challenging because of the weak rovibrational transition ladder of H{sub 2} and the inability to spatially resolve different emission components within the circumstellar environment. To address both of these issues, we present new contemporaneous measurements of CO and H{sub 2} absorption through the 'warm molecular layer' of the protoplanetary disk around the Classical T Tauri Star RW Aurigae A. We use a newly commissioned observing mode of the Hubble Space Telescope Cosmic Origins Spectrograph to detect warm H{sub 2} absorption in this region for the first time. An analysis of the emission and absorption spectrum of RW Aur shows components from the accretion region near the stellar photosphere, the molecular disk, and several outflow components. The warm H{sub 2} and CO absorption lines are consistent with a disk origin. We model the 1092-1117 spectrum of RW Aur to derive log{sub 10} N(H{sub 2}) = 19.90{sub ?0.22}{sup +0.33} cm{sup 2} at T {sub rot}(H{sub 2}) = 440 39 K. The CO A - X bands observed from 1410 to 1520 are best fit by log{sub 10} N(CO) = 16.1 {sub ?0.5}{sup +0.3} cm{sup 2} at T {sub rot}(CO) = 200{sub ?125}{sup +650} K. Combining direct measurements of the H I, H{sub 2}, and CO column densities, we find a molecular fraction in the warm disk surface of f {sub H2} ? 0.47 and derive a molecular abundance ratio of CO/H{sub 2} = 1.6{sub ?1.3}{sup +4.7} 10{sup 4}, both consistent with canonical interstellar dense cloud values.

  3. Ab initio investigation of electronic and vibrational contributions to linear and nonlinear dielectric properties of ice

    SciTech Connect (OSTI)

    Casassa, S.; Baima, J.; Mahmoud, A.; Kirtman, B.

    2014-06-14

    Electronic and vibrational contributions to the static and dynamic (hyper)polarizability tensors of ice XI and model structures of ordinary hexagonal ice have been theoretically investigated. Calculations were carried out by the finite field nuclear relaxation method for periodic systems (FF-NR) recently implemented in the CRYSTAL code, using the coupled-perturbed Kohn-Sham approach (CPKS) for evaluating the required electronic properties. The effect of structure on the static electronic polarizabilities (dielectric constants) and second-hyperpolarizabilities is minimal. On the other hand, the vibrational contributions to the polarizabilities were found to be significant. A reliable evaluation of these (ionic) contributions allows one to discriminate amongst ice phases characterized by different degrees of proton-order, primarily through differences caused by librational motions. Transverse static and dynamic vibrational (hyper)polarizabilities were found by extrapolating calculations for slabs of increasing size, in order to eliminate substantial surface contributions.

  4. In Situ Airborne Instrumentation: Addressing and Solving Measurement Problems in Ice Clouds

    SciTech Connect (OSTI)

    Baumgardner, Darrel; Kok, Greg; Avallone, L.; Bansemer, A.; Borrmann, S.; Brown, P.; Bundke, U.; Chuang, P. Y.; Cziczo, D.; Field, P.; Gallagher, M.; Gayet, J. -F.; Korolev, A.; Kraemer, M.; McFarquhar, G.; Mertes, S.; Moehler, O.; Lance, S.; Lawson, P.; Petters, M. D.; Pratt, K.; Roberts, G.; Rogers, D.; Stetzer, O.; Stith, J.; Strapp, W.; Twohy, C.; Wendisch, M.

    2012-02-01

    A meeting of 31 international experts on in situ measurements from aircraft was held to identify unresolved questions concerning ice formation and evolution in ice clouds, assess the current state of instrumentation that can address these problems, introduce emerging technology that may overcome current measurement issues and recommend future courses of action that can improve our understanding of ice cloud microphysical processes and their impact on the environment. The meeting proceedings and outcome has been described in detail in a manuscript submitted to the Bulletin of the American Meteorological Society (BAMS) on March 24, 2011. This paper is currently under review. The remainder of this summary, in the following pages, is the text of the BAMS article. A technical note that will be published by the National Center for Atmospheric Research is currently underway and is expected to be published before the end of the year.

  5. In Situ Airborne Instrumentation: Addressing and Solving Measurement Problems in Ice Clouds

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Baumgardner, Darrel; Kok, Greg; Avallone, L.; Bansemer, A.; Borrmann, S.; Brown, P.; Bundke, U.; Chuang, P. Y.; Cziczo, D.; Field, P.; et al

    2012-02-01

    A meeting of 31 international experts on in situ measurements from aircraft was held to identify unresolved questions concerning ice formation and evolution in ice clouds, assess the current state of instrumentation that can address these problems, introduce emerging technology that may overcome current measurement issues and recommend future courses of action that can improve our understanding of ice cloud microphysical processes and their impact on the environment. The meeting proceedings and outcome has been described in detail in a manuscript submitted to the Bulletin of the American Meteorological Society (BAMS) on March 24, 2011. This paper is currently undermore » review. The remainder of this summary, in the following pages, is the text of the BAMS article. A technical note that will be published by the National Center for Atmospheric Research is currently underway and is expected to be published before the end of the year.« less

  6. Sensitivity of IceCube-DeepCore to neutralino dark matter in the MSSM-25

    SciTech Connect (OSTI)

    Silverwood, Hamish; Adams, Jenni; Brown, Anthony M; Scott, Pat; Danninger, Matthias; Savage, Christopher; Edsj, Joakim; Hultqvist, Klas E-mail: patscott@physics.mcgill.ca E-mail: savage@physics.utah.edu E-mail: jenni.adams@canterbury.ac.nz E-mail: klas.hultqvist@fysik.su.se

    2013-03-01

    We analyse the sensitivity of IceCube-DeepCore to annihilation of neutralino dark matter in the solar core, generated within a 25 parameter version of the minimally supersymmetric standard model (MSSM-25). We explore the 25-dimensional parameter space using scanning methods based on importance sampling and using DarkSUSY 5.0.6 to calculate observables. Our scans produced a database of 6.02 million parameter space points with neutralino dark matter consistent with the relic density implied by WMAP 7-year data, as well as with accelerator searches. We performed a model exclusion analysis upon these points using the expected capabilities of the IceCube-DeepCore Neutrino Telescope. We show that IceCube-DeepCore will be sensitive to a number of models that are not accessible to direct detection experiments such as SIMPLE, COUPP and XENON100, indirect detection using Fermi-LAT observations of dwarf spheroidal galaxies, nor to current LHC searches.

  7. Multilayer formation and evaporation of deuterated ices in prestellar and protostellar cores

    SciTech Connect (OSTI)

    Taquet, Vianney; Charnley, Steven B.; Sipil, Olli

    2014-08-10

    Extremely large deuteration of several molecules has been observed toward prestellar cores and low-mass protostars for a decade. New observations performed toward low-mass protostars suggest that water presents a lower deuteration in the warm inner gas than in the cold external envelope. We coupled a gas-grain astrochemical model with a one-dimensional model of a collapsing core to properly follow the formation and the deuteration of interstellar ices as well as their subsequent evaporation in the low-mass protostellar envelopes with the aim of interpreting the spatial and temporal evolutions of their deuteration. The astrochemical model follows the formation and the evaporation of ices with a multilayer approach and also includes a state-of-the-art deuterated chemical network by taking the spin states of H{sub 2} and light ions into account. Because of their slow formation, interstellar ices are chemically heterogeneous and show an increase of their deuterium fractionation toward the surface. The differentiation of the deuteration in ices induces an evolution of the deuteration within protostellar envelopes. The warm inner region is poorly deuterated because it includes the whole molecular content of ices, while the deuteration predicted in the cold external envelope scales with the highly deuterated surface of ices. We are able to reproduce the observed evolution of water deuteration within protostellar envelopes, but we are still unable to predict the super-high deuteration observed for formaldehyde and methanol. Finally, the extension of this study to the deuteration of complex organics, important for the prebiotic chemistry, shows good agreement with the observations, suggesting that we can use the deuteration to retrace their mechanisms and their moments of formation.

  8. Neutrino oscillations with IceCube DeepCore and PINGU

    SciTech Connect (OSTI)

    DeYoung, T.; Collaboration: IceCube-PINGU Collaboration

    2014-11-18

    The IceCube neutrino telescope was augmented with the DeepCore infill array, completed in the 2010/11 austral summer, to enhance its response to neutrinos below 100 GeV. At these energies, neutrino oscillation effects are visible in the flux of atmospheric neutrinos traversing path lengths comparable to the Earth's diameter. Initial measurements of muon neutrino disappearance parameters using data from DeepCore are presented, as well as an estimate of potential future precision. In addition, plans for a Precision IceCube Next Generation Upgrade (PINGU), which could permit determination of the neutrino mass hierarchy within the coming decade, are discussed.

  9. Bio-based Deicing/Anti-Icing Fluids - Energy Innovation Portal

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Find More Like This Return to Search Bio-based Deicing/Anti-Icing Fluids Battelle Memorial Institute Contact BMI About This Technology Technology Marketing SummaryThis technology is for preparing lower-toxicity, less corrosive, and typically bio-based deicing/anti-icing fluids for aerospace and non-aerospace applications.DescriptionThe use of bio-based ingredients allows the toxicity and corrosivity as well as the carbon footprint to be reduced. A major aspect of this technology is the

  10. Effects of exchange bias on magnetotransport in permalloy kagome artificial spin ice

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Le, B. L.; Rench, D. W.; Misra, R.; O’Brien, L.; Leighton, C.; Samarth, N.; Schiffer, P.

    2015-02-01

    We investigate the magnetotransport properties of connected kagome artificial spin ice networks composed of permalloy nanowires. Our data show clear evidence of magnetic switching among the wires, both in the longitudinal and transverse magnetoresistance. An unusual asymmetry with field sweep direction appears at temperatures below about 20 K that appears to be associated with exchange bias resulting from surface oxidation of permalloy, and which disappears in alumina-capped samples. These results demonstrate that exchange bias is a phenomenon that must be considered in understanding the physics of such artificial spin ice systems, and that opens up new possibilities for their control.

  11. Laboratory investigations of irradiated acetonitrile-containing ices on an interstellar dust analog

    SciTech Connect (OSTI)

    Abdulgalil, Ali G. M.; Marchione, Demian; Rosu-Finsen, Alexander; Collings, Mark P.; McCoustra, Martin R. S.

    2012-07-15

    Reflection-absorption infrared spectroscopy is used to study the impact of low-energy electron irradiation of acetonitrile-containing ices, under conditions close to those in the dense star-forming regions in the interstellar medium. Both the incident electron energy and the surface coverage were varied. The experiments reveal that solid acetonitrile is desorbed from its ultrathin solid films with a cross section of the order of 10{sup -17} cm{sup 2}. Evidence is presented for a significantly larger desorption cross section for acetonitrile molecules at the water-ice interface, similar to that previously observed for the benzene-water system.

  12. Optimal Initial Conditions for Coupling Ice Sheet Models to Earth System

    Office of Scientific and Technical Information (OSTI)

    Models. (Journal Article) | SciTech Connect Optimal Initial Conditions for Coupling Ice Sheet Models to Earth System Models. Citation Details In-Document Search Title: Optimal Initial Conditions for Coupling Ice Sheet Models to Earth System Models. Abstract not provided. Authors: Perego, Mauro ; Price, Stephen ; Stadler, Georg Publication Date: 2014-04-01 OSTI Identifier: 1142266 Report Number(s): SAND2014-2781J 507169 DOE Contract Number: DE-AC04-94AL85000 Resource Type: Journal Article

  13. Predicting Land-Ice Retreat and Sea-Level Rise with the Community Earth

    Office of Scientific and Technical Information (OSTI)

    System Model (Conference) | SciTech Connect Predicting Land-Ice Retreat and Sea-Level Rise with the Community Earth System Model Citation Details In-Document Search Title: Predicting Land-Ice Retreat and Sea-Level Rise with the Community Earth System Model Coastal stakeholders need defensible predictions of 21st century sea-level rise (SLR). IPCC assessments suggest 21st century SLR of {approx}0.5 m under aggressive emission scenarios. Semi-empirical models project SLR of {approx}1 m or more

  14. Progress in coupling Land Ice and Ocean Models in the MPAS Framework

    Office of Scientific and Technical Information (OSTI)

    (Conference) | SciTech Connect in coupling Land Ice and Ocean Models in the MPAS Framework Citation Details In-Document Search Title: Progress in coupling Land Ice and Ocean Models in the MPAS Framework Authors: Hoffman, Matthew J. [1] + Show Author Affiliations Los Alamos National Laboratory Publication Date: 2013-02-14 OSTI Identifier: 1063255 Report Number(s): LA-UR-13-20973 DOE Contract Number: AC52-06NA25396 Resource Type: Conference Resource Relation: Conference: Community Earth System

  15. Progress on MPAS Land Ice Model Development (Conference) | SciTech Connect

    Office of Scientific and Technical Information (OSTI)

    on MPAS Land Ice Model Development Citation Details In-Document Search Title: Progress on MPAS Land Ice Model Development × You are accessing a document from the Department of Energy's (DOE) SciTech Connect. This site is a product of DOE's Office of Scientific and Technical Information (OSTI) and is provided as a public service. Visit OSTI to utilize additional information resources in energy science and technology. A paper copy of this document is also available for sale to the public from the

  16. Progress in coupling Land Ice and Ocean Models in the MPAS Framework

    Office of Scientific and Technical Information (OSTI)

    (Conference) | SciTech Connect in coupling Land Ice and Ocean Models in the MPAS Framework Citation Details In-Document Search Title: Progress in coupling Land Ice and Ocean Models in the MPAS Framework × You are accessing a document from the Department of Energy's (DOE) SciTech Connect. This site is a product of DOE's Office of Scientific and Technical Information (OSTI) and is provided as a public service. Visit OSTI to utilize additional information resources in energy science and

  17. Development of a land ice core for the Model for Prediction Across Scales

    Office of Scientific and Technical Information (OSTI)

    (MPAS) (Conference) | SciTech Connect of a land ice core for the Model for Prediction Across Scales (MPAS) Citation Details In-Document Search Title: Development of a land ice core for the Model for Prediction Across Scales (MPAS) No abstract prepared. Authors: Hoffman, Matthew J [1] + Show Author Affiliations Los Alamos National Laboratory Publication Date: 2012-06-25 OSTI Identifier: 1044843 Report Number(s): LA-UR-12-22469 TRN: US201214%%525 DOE Contract Number: AC52-06NA25396 Resource

  18. Development of a land ice core for the Model for Prediction Across Scales

    Office of Scientific and Technical Information (OSTI)

    (MPAS) (Conference) | SciTech Connect of a land ice core for the Model for Prediction Across Scales (MPAS) Citation Details In-Document Search Title: Development of a land ice core for the Model for Prediction Across Scales (MPAS) × You are accessing a document from the Department of Energy's (DOE) SciTech Connect. This site is a product of DOE's Office of Scientific and Technical Information (OSTI) and is provided as a public service. Visit OSTI to utilize additional information resources

  19. Development of a land ice core for the Model for Prediction Across Scales

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    (MPAS) (Conference) | SciTech Connect a land ice core for the Model for Prediction Across Scales (MPAS) Citation Details In-Document Search Title: Development of a land ice core for the Model for Prediction Across Scales (MPAS) No abstract prepared. Authors: Hoffman, Matthew J [1] + Show Author Affiliations Los Alamos National Laboratory Publication Date: 2012-06-25 OSTI Identifier: 1044843 Report Number(s): LA-UR-12-22469 TRN: US201214%%525 DOE Contract Number: AC52-06NA25396 Resource Type:

  20. Update on Greenland Ice Sheet Simulations In CISM and CESM (Conference) |

    Office of Scientific and Technical Information (OSTI)

    SciTech Connect Update on Greenland Ice Sheet Simulations In CISM and CESM Citation Details In-Document Search Title: Update on Greenland Ice Sheet Simulations In CISM and CESM × You are accessing a document from the Department of Energy's (DOE) SciTech Connect. This site is a product of DOE's Office of Scientific and Technical Information (OSTI) and is provided as a public service. Visit OSTI to utilize additional information resources in energy science and technology. A paper copy of this

  1. Quadrature conductivity: A quantitative indicator of bacterial abundance in porous media

    SciTech Connect (OSTI)

    Chi Zhang; Andre Revil; Yoshiko Fujita; Junko Munakata-Marr; George Redden

    2014-09-01

    ABSTRACT The abundance and growth stages of bacteria in subsurface porous media affect the concentrations and distributions of charged species within the solid-solution interfaces. Therefore, spectral induced polarization (SIP) measurements can be used to monitor changes in bacterial biomass and growth stage. Our goal was to gain a better understanding of the SIP response of bacteria present in a porous material. Bacterial cell surfaces possess an electric double layer and therefore become polarized in an electric field. We performed SIP measurements over the frequency range of 0.11 kHz on cell suspensions alone and cell suspensions mixed with sand at four pore water conductivities. We used Zymomonas mobilis at four different cell densities (in- cluding the background). The quadrature conductivity spectra exhibited two peaks, one around 0.050.10 Hz and the other around 110 Hz. Because SIP measurements on bacterial suspensions are typically made at frequencies greater than 1 Hz, these peaks have not been previously reported. In the bac-terial suspensions in growth medium, the quadrature conduc-tivity at peak I was linearly proportional to the density of the bacteria. For the case of the suspensions mixed with sands, we observed that peak II presented a smaller increase in the quadrature conductivity with the cell density. A comparison of the experiments with and without sand grains illustrated the effect of the porous medium on the overall quadrature con- ductivity response (decrease in the amplitude and shift of the peaks to the lower frequencies). Our results indicate that for a given porous medium, time-lapse SIP has potential for mon- itoring changes in bacterial abundance within porous media.

  2. Capture of a neutron to excited states of a {sup 9}Be nucleus taking into account resonance at 622 keV

    SciTech Connect (OSTI)

    Dubovichenko, S. B.

    2013-10-15

    Radiative capture of a neutron to the ground and excited states of the 9Be nucleus is considered using the potential cluster model with forbidden states and with classification of cluster states by the Young schemes taking into account resonance at 622 keV for thermal and astrophysical energies.

  3. ELEMENTAL ABUNDANCE RATIOS IN STARS OF THE OUTER GALACTIC DISK. IV. A NEW SAMPLE OF OPEN CLUSTERS

    SciTech Connect (OSTI)

    Yong, David; Carney, Bruce W.; Friel, Eileen D. E-mail: bruce@physics.unc.edu

    2012-10-01

    We present radial velocities and chemical abundances for nine stars in the old, distant open clusters Be18, Be21, Be22, Be32, and PWM4. For Be18 and PWM4, these are the first chemical abundance measurements. Combining our data with literature results produces a compilation of some 68 chemical abundance measurements in 49 unique clusters. For this combined sample, we study the chemical abundances of open clusters as a function of distance, age, and metallicity. We confirm that the metallicity gradient in the outer disk is flatter than the gradient in the vicinity of the solar neighborhood. We also confirm that the open clusters in the outer disk are metal-poor with enhancements in the ratios [{alpha}/Fe] and perhaps [Eu/Fe]. All elements show negligible or small trends between [X/Fe] and distance (<0.02 dex kpc{sup -1}), but for some elements, there is a hint that the local (R{sub GC} < 13 kpc) and distant (R{sub GC} > 13 kpc) samples may have different trends with distance. There is no evidence for significant abundance trends versus age (<0.04 dex Gyr{sup -1}). We measure the linear relation between [X/Fe] and metallicity, [Fe/H], and find that the scatter about the mean trend is comparable to the measurement uncertainties. Comparison with solar neighborhood field giants shows that the open clusters share similar abundance ratios [X/Fe] at a given metallicity. While the flattening of the metallicity gradient and enhanced [{alpha}/Fe] ratios in the outer disk suggest a chemical enrichment history different from that of the solar neighborhood, we echo the sentiments expressed by Friel et al. that definitive conclusions await homogeneous analyses of larger samples of stars in larger numbers of clusters. Arguably, our understanding of the evolution of the outer disk from open clusters is currently limited by systematic abundance differences between various studies.

  4. Heat sources within the Greenland Ice Sheet: dissipation, temperate paleo-firn and cryo-hydrologic warming

    SciTech Connect (OSTI)

    Lthi, M. P.; Ryser, C.; Andrews, L. C.; Catania, G. A.; Funk, M.; Hawley, R. L.; Hoffman, M. J.; Neumann, T. A.

    2015-01-01

    Ice temperature profiles from the Greenland Ice Sheet contain information on the deformation history, past climates and recent warming. We present full-depth temperature profiles from two drill sites on a flow line passing through Swiss Camp, West Greenland. Numerical modeling reveals that ice temperatures are considerably higher than would be expected from heat diffusion and dissipation alone. The possible causes for this extra heat are evaluated using a Lagrangian heat flow model. The model results reveal that the observations can be explained with a combination of different processes: enhanced dissipation (strain heating) in ice-age ice, temperate paleo-firn, and cryo-hydrologic warming in deep crevasses.

  5. Heat sources within the Greenland Ice Sheet: dissipation, temperate paleo-firn and cryo-hydrologic warming

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Lüthi, M. P.; Ryser, C.; Andrews, L. C.; Catania, G. A.; Funk, M.; Hawley, R. L.; Hoffman, M. J.; Neumann, T. A.

    2015-01-01

    Ice temperature profiles from the Greenland Ice Sheet contain information on the deformation history, past climates and recent warming. We present full-depth temperature profiles from two drill sites on a flow line passing through Swiss Camp, West Greenland. Numerical modeling reveals that ice temperatures are considerably higher than would be expected from heat diffusion and dissipation alone. The possible causes for this extra heat are evaluated using a Lagrangian heat flow model. The model results reveal that the observations can be explained with a combination of different processes: enhanced dissipation (strain heating) in ice-age ice, temperate paleo-firn, and cryo-hydrologic warmingmore » in deep crevasses.« less

  6. Abundances of presolar graphite and SiC from supernovae and AGB stars in the Murchison meteorite

    SciTech Connect (OSTI)

    Amari, Sachiko; Zinner, Ernst; Gallino, Roberto

    2014-05-02

    Pesolar graphite grains exhibit a range of densities (1.65 – 2.20 g/cm{sup 3}). We investigated abundances of presolar graphite grains formed in supernovae and in asymptotic giant branch (AGB) stars in the four density fractions KE3, KFA1, KFB1 and KFC1 extracted from the Murchison meteorite to probe dust productions in these stellar sources. Seventy-six and 50% of the grains in the low-density fractions KE3 and KFA1, respectively, are supernova grains, while only 7.2% and 0.9% of the grains in the high-density fractions KFB1 and KFC1 have a supernova origin. Grains of AGB star origin are concentrated in the high-density fractions KFB1 and KFC1. From the C isotopic distributions of these fractions and the presence of s-process Kr with {sup 86}Kr/{sup 82}Kr = 4.43±0.46 in KFC1, we estimate that 76% and 80% of the grains in KFB1 and KFC1, respectively, formed in AGB stars. From the abundance of graphite grains in the Murchison meteorite, 0.88 ppm, the abundances of graphite from supernovae and AGB stars are 0.24 ppm and 0.44 ppm, respectively: the abundances of graphite in supernovae and AGB stars are comparable. In contrast, it has been known that 1% of SiC grains formed in supernovae and 95% formed in AGB stars in meteorites. Since the abundance of SiC grains is 5.85 ppm in the Murchison meteorite, the abundances of SiC from supernovae and AGB stars are 0.063 ppm and 5.6 ppm, respectively: the dominant source of SiC grains is AGB stars. Since SiC grains are harder and likely to survive better in space than graphite grains, the abundance of supernova graphite grains, which is higher than that of supernova SiC grains, indicates that supernovae proficiently produce graphite grains. Graphite grains from AGB stars are, in contrast, less abundant that SiC grains from AGB stars (0.44 ppm vs. 5.6 ppm). It is difficult to derive firm conclusions for graphite and SiC formation in AGB stars due to the difference in susceptibility to grain destruction. Metallicity of the parent AGB stars of graphite grains is much lower than that of SiC grains and the difference in metallicity might also have affected to the difference in the abundances in the Murchison meteorite.

  7. Soil Physicochemical Characteristics from Ice Wedge Polygons, Barrow, Alaska, Ver. 1

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Chowdhury, Taniya; Graham, David

    2013-12-08

    This dataset provides details about soil cores (active layer and permafrost) collected from ice-wedge polygons during field expeditions to Barrow Environmental Observatory, Alaska in April, 2012 and 2013. Core information available are exact core locations; soil horizon descriptions and characteristics; and fundamental soil physico-chemical properties.

  8. Soil Physicochemical Characteristics from Ice Wedge Polygons, Barrow, Alaska, Ver. 1

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Chowdhury, Taniya

    2014-03-24

    This dataset provides details about soil cores (active layer and permafrost) collected from ice-wedge polygons during field expeditions to Barrow Environmental Observatory, Alaska in April, 2012 and 2013. Core information available are exact core locations; soil horizon descriptions and characteristics; and fundamental soil physico-chemical properties.

  9. Cryogenic EBSD reveals structure of directionally solidified icepolymer composite

    SciTech Connect (OSTI)

    Donius, Amalie E.; Obbard, Rachel W.; Burger, Joan N.; Hunger, Philipp M.; Baker, Ian; Doherty, Roger D.; Wegst, Ulrike G.K.

    2014-07-01

    Despite considerable research efforts on directionally solidified or freeze-cast materials in recent years, little fundamental knowledge has been gained that links model with experiment. In this contribution, the cryogenic characterization of directionally solidified polymer solutions illustrates, how powerful cryo-scanning electron microscopy combined with electron backscatter diffraction is for the structural characterization of icepolymer composite materials. Under controlled sublimation, the freeze-cast polymer scaffold structure is revealed and imaged with secondary electrons. Electron backscatter diffraction fabric analysis shows that the ice crystals, which template the polymer scaffold and create the lamellar structure, have a-axes oriented parallel to the direction of solidification and the c-axes perpendicular to it. These results indicate the great potential of both cryo-scanning electron microscopy and cryo-electron backscatter diffraction in gaining fundamental knowledge of structurepropertyprocessing correlations. - Highlights: Cryo-SEM of freeze-cast polymer solution reveals an ice-templated structure. Cryo-EBSD reveals the ice crystal a-axis to parallel the solidification direction. The honeycomb-like polymer phase favors columnar ridges only on one side. Combining cryo-SEM with EBSD links solidification theory with experiment.

  10. Soil Physicochemical Characteristics from Ice Wedge Polygons, Barrow, Alaska, Ver. 1

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Chowdhury, Taniya

    This dataset provides details about soil cores (active layer and permafrost) collected from ice-wedge polygons during field expeditions to Barrow Environmental Observatory, Alaska in April, 2012 and 2013. Core information available are exact core locations; soil horizon descriptions and characteristics; and fundamental soil physico-chemical properties.

  11. ANALYSIS OF RICIN TOXIN PREPARATIONS FOR CARBOHYDRATE AND FATTY ACID ABUNDANCE AND ISOTOPE RATIO INFORMATION

    SciTech Connect (OSTI)

    Wunschel, David S.; Kreuzer-Martin, Helen W.; Antolick, Kathryn C.; Colburn, Heather A.; Moran, James J.; Melville, Angela M.

    2009-12-01

    This report describes method development and preliminary evaluation for analyzing castor samples for signatures of purifying ricin. Ricin purification from the source castor seeds is essentially a problem of protein purification using common biochemical methods. Indications of protein purification will likely manifest themselves as removal of the non-protein fractions of the seed. Two major, non-protein, types of biochemical constituents in the seed are the castor oil and various carbohydrates. The oil comprises roughly half the seed weight while the carbohydrate component comprises roughly half of the remaining mash left after oil and hull removal. Different castor oil and carbohydrate components can serve as indicators of specific toxin processing steps. Ricinoleic acid is a relatively unique fatty acid in nature and is the most abundant component of castor oil. The loss of ricinoleic acid indicates a step to remove oil from the seeds. The relative amounts of carbohydrates and carbohydrate-like compounds, including arabinose, xylose, myo-inositol fucose, rhamnose, glucosamine and mannose detected in the sample can also indicate specific processing steps. For instance, the differential loss of arabinose relative to mannose and N-acetyl glucosamine indicates enrichment for the protein fraction of the seed using protein precipitation. The methods developed in this project center on fatty acid and carbohydrate extraction from castor samples followed by derivatization to permit analysis by gas chromatography-mass spectrometry (GC-MS). Method descriptions herein include: the source and preparation of castor materials used for method evaluation, the equipment and description of procedure required for chemical derivatization, and the instrument parameters used in the analysis. Two types of derivatization methods describe analysis of carbohydrates and one procedure for analysis of fatty acids. Two types of GC-MS analysis is included in the method development, one employing a quadrupole MS system for compound identification and an isotope ratio MS for measuring the stable isotope ratios of deuterium and hydrogen (D/H) in fatty acids. Finally, the method for analyzing the compound abundance data is included. This study indicates that removal of ricinoleic acid is a conserved consequence of each processing step we tested. Furthermore, the stable isotope D/H ratio of ricinoleic acid distinguished between two of the three castor seed sources. Concentrations of arabinose, xylose, mannose, glucosamine and myo-inositol differentiated between crude or acetone extracted samples and samples produced by protein precipitation. Taken together these data illustrate the ability to distinguish between processes used to purify a ricin sample as well as potentially the source seeds.

  12. Molecular dynamics simulations of D{sub 2}O ice photodesorption

    SciTech Connect (OSTI)

    Arasa, C.; Andersson, S.; Cuppen, H. M.; Dishoeck, E. F. van; Kroes, G. J.

    2011-04-28

    Molecular dynamics (MD) calculations have been performed to study the ultraviolet (UV) photodissociation of D{sub 2}O in an amorphous D{sub 2}O ice surface at 10, 20, 60, and 90 K, in order to investigate the influence of isotope effects on the photodesorption processes. As for H{sub 2}O, the main processes after UV photodissociation are trapping and desorption of either fragments or D{sub 2}O molecules. Trapping mainly takes place in the deeper monolayers of the ice, whereas desorption occurs in the uppermost layers. There are three desorption processes: D atom, OD radical, and D{sub 2}O molecule photodesorption. D{sub 2}O desorption takes places either by direct desorption of a recombined D{sub 2}O molecule, or when an energetic D atom produced by photodissociation kicks a surrounding D{sub 2}O molecule out of the surface by transferring part of its momentum. Desorption probabilities are calculated for photoexcitation of D{sub 2}O in the top four monolayers and are compared quantitatively with those for H{sub 2}O obtained from previous MD simulations of UV photodissociation of amorphous water ice at different ice temperatures [Arasa et al., J. Chem. Phys. 132, 184510 (2010)]. The main conclusions are the same, but the average D atom photodesorption probability is smaller than that of the H atom (by about a factor of 0.9) because D has lower kinetic energy than H, whereas the average OD radical photodesorption probability is larger than that of OH (by about a factor of 2.5-2.9 depending on ice temperature) because OD has higher translational energy than OH for every ice temperature studied. The average D{sub 2}O photodesorption probability is larger than that of H{sub 2}O (by about a factor of 1.4-2.3 depending on ice temperature), and this is entirely due to a larger contribution of the D{sub 2}O kick-out mechanism. This is an isotope effect: the kick-out mechanism is more efficient for D{sub 2}O ice, because the D atom formed after D{sub 2}O photodissociation has a larger momentum than photogenerated H atoms from H{sub 2}O, and D transfers momentum more easily to D{sub 2}O than H to H{sub 2}O. The total (OD + D{sub 2}O) yield has been compared with experiments and the total (OH + H{sub 2}O) yield from previous simulations. We find better agreement when we compare experimental yields with calculated yields for D{sub 2}O ice than when we compare with calculated yields for H{sub 2}O ice.

  13. Ice Nucleation of Bare and Sulfuric Acid-coated Mineral Dust Particles and Implication for Cloud Properties

    SciTech Connect (OSTI)

    Kulkarni, Gourihar R.; Sanders, Cassandra N.; Zhang, Kai; Liu, Xiaohong; Zhao, Chun

    2014-08-27

    Ice nucleation properties of different dust species coated with soluble material are not well understood. We determined the ice nucleation ability of bare and sulfuric acid coated mineral dust particles as a function of temperature (-25 to -35 deg C) and relative humidity with respect to water (RHw). Five different mineral dust species: Arizona test dust (ATD), illite, montmorillonite, quartz and kaolinite were dry dispersed and size-selected at 150 nm and exposed to sulfuric acid vapors in the coating apparatus. The condensed sulfuric acid soluble mass fraction per particle was estimated from the cloud condensation nuclei activated fraction measurements. The fraction of dust particles nucleating ice at various temperatures and RHw was determined using a compact ice chamber. In water-subsaturated conditions, compared to bare dust particles, we found that only coated ATD particles showed suppression of ice nucleation ability while other four dust species did not showed the effect of coating on the fraction of particles nucleating ice. The results suggest that interactions between the dust surface and sulfuric acid vapor are important, such that interactions may or may not modify the surface via chemical reactions with sulfuric acid. At water-supersaturated conditions we did not observed the effect of coating, i.e. the bare and coated dust particles had similar ice nucleation behavior.

  14. Overexpression of Late Embryogenesis Abundant 14 enhances Arabidopsis salt stress tolerance

    SciTech Connect (OSTI)

    Jia, Fengjuan Qi, Shengdong Li, Hui Liu, Pu Li, Pengcheng Wu, Changai Zheng, Chengchao Huang, Jinguang

    2014-11-28

    Highlights: It is the first time to investigate the biological function of AtLEA14 in salt stress response. AtLEA14 enhances the salt stress tolerance both in Arabidopsis and yeast. AtLEA14 responses to salt stress by stabilizing AtPP2-B11, an E3 ligase, under normal or salt stress conditions. - Abstract: Late embryogenesis abundant (LEA) proteins are implicated in various abiotic stresses in higher plants. In this study, we identified a LEA protein from Arabidopsis thaliana, AtLEA14, which was ubiquitously expressed in different tissues and remarkably induced with increased duration of salt treatment. Subcellular distribution analysis demonstrated that AtLEA14 was mainly localized in the cytoplasm. Transgenic Arabidopsis and yeast overexpressing AtLEA14 all exhibited enhanced tolerance to high salinity. The transcripts of salt stress-responsive marker genes (COR15a, KIN1, RD29B and ERD10) were overactivated in AtLEA14 overexpressing lines compared with those in wild type plants under normal or salt stress conditions. In vivo and in vitro analysis showed that AtLEA14 could effectively stabilize AtPP2-B11, an important E3 ligase. These results suggested that AtLEA14 had important protective functions under salt stress conditions in Arabidopsis.

  15. mRNA Transcript Abundance during Plant Growth and the Influence of Li+ Exposure

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Duff, M. C.; Kuhne, W. W.; Halverson, N. V.; Chang, C. -S.; Kitamura, E.; Hawthorn, L.; Martinez, N. E.; Stafford, C.; Milliken, C. E.; Caldwell, E. F.; et al

    2014-10-23

    Lithium (Li) toxicity in plants is, at a minimum, a function of Li+ concentration, exposure time, species and growth conditions. Most plant studies with Li+ focus on short-term acute exposures. This study examines short- and long-term effects of Li+ exposure in Arabidopsis with Li+ uptake studies and measured shoot mRNA transcript abundance levels in treated and control plants. Stress, pathogen-response and arabinogalactan protein genes were typically more up-regulated in older (chronic, low level) Li+-treatment plants and in the much younger plants from acute high-level exposures. The gene regulation behavior of high-level Li+ resembled prior studies due to its influence on:more »inositol synthesis, 1-aminocyclopropane-1-carboxylate synthases and membrane ion transport. In contrast, chronically-exposed plants had gene regulation responses that were indicative of pathogen, cold, and heavy-metal stress, cell wall degradation, ethylene production, signal transduction, and calcium-release modulation. Acute Li+ exposure phenocopies magnesium-deficiency symptoms and is associated with elevated expression of stress response genes that could lead to consumption of metabolic and transcriptional energy reserves and the dedication of more resources to cell development. In contrast, chronic Li+ exposure increases expression signal transduction genes. The identification of new Li+-sensitive genes and a gene-based “response plan” for acute and chronic Li+ exposure are delineated.« less

  16. Abundance of {sup 14}C in biomass fractions of wastes and solid recovered fuels

    SciTech Connect (OSTI)

    Fellner, Johann Rechberger, Helmut

    2009-05-15

    In recent years thermal utilization of mixed wastes and solid recovered fuels has become of increasing importance in European waste management. Since wastes or solid recovered fuels are generally composed of fossil and biogenic materials, only part of the CO{sub 2} emissions is accounted for in greenhouse gas inventories or emission trading schemes. A promising approach for determining this fraction is the so-called radiocarbon method. It is based on different ratios of the carbon isotopes {sup 14}C and {sup 12}C in fossil and biogenic fuels. Fossil fuels have zero radiocarbon, whereas biogenic materials are enriched in {sup 14}C and reflect the {sup 14}CO{sub 2} abundance of the ambient atmosphere. Due to nuclear weapons tests in the past century, the radiocarbon content in the atmosphere has not been constant, which has resulted in a varying {sup 14}C content of biogenic matter, depending on the period of growth. In the present paper {sup 14}C contents of different biogenic waste fractions (e.g., kitchen waste, paper, wood), as well as mixtures of different wastes (household, bulky waste, and commercial waste), and solid recovered fuels are determined. The calculated {sup 14}C content of the materials investigated ranges between 98 and 135 pMC.

  17. THE STELLAR HALOS OF MASSIVE ELLIPTICAL GALAXIES. II. DETAILED ABUNDANCE RATIOS AT LARGE RADIUS

    SciTech Connect (OSTI)

    Greene, Jenny E.; Murphy, Jeremy D.; Graves, Genevieve J.; Gunn, James E.; Raskutti, Sudhir; Comerford, Julia M.; Gebhardt, Karl

    2013-10-20

    We study the radial dependence in stellar populations of 33 nearby early-type galaxies with central stellar velocity dispersions ?{sub *} ?> 150 km s{sup 1}. We measure stellar population properties in composite spectra, and use ratios of these composites to highlight the largest spectral changes as a function of radius. Based on stellar population modeling, the typical star at 2R{sub e} is old (?10 Gyr), relatively metal-poor ([Fe/H] ? 0.5), and ?-enhanced ([Mg/Fe] ? 0.3). The stars were made rapidly at z ? 1.5-2 in shallow potential wells. Declining radial gradients in [C/Fe], which follow [Fe/H], also arise from rapid star formation timescales due to declining carbon yields from low-metallicity massive stars. In contrast, [N/Fe] remains high at large radius. Stars at large radius have different abundance ratio patterns from stars in the center of any present-day galaxy, but are similar to average Milky Way thick disk stars. Our observations are thus consistent with a picture in which the stellar outskirts are built up through minor mergers with disky galaxies whose star formation is truncated early (z ? 1.5-2)

  18. LIGHT-ELEMENT ABUNDANCES OF GIANT STARS IN THE GLOBULAR CLUSTER M71 (NGC6838)

    SciTech Connect (OSTI)

    Cordero, M. J.; Pilachowski, C. A.; Vesperini, E.; Johnson, C. I. E-mail: catyp@astro.indiana.edu E-mail: cjohnson@cfa.harvard.edu

    2015-02-10

    Aluminum is the heaviest light element displaying large star-to-star variations in Galactic globular clusters (GCs). This element may provide additional insight into the origin of the multiple populations, now known to be common place in GCs, and also the nature of the first-generation stars responsible for a cluster's chemical inhomogeneities. In a previous analysis, we found that unlike more metal-poor GCs, 47 Tuc did not exhibit a strong Na-Al correlation, which motivates a careful study of the similar metallicity but less massive GC M71. We present chemical abundances of O, Na, Al, and Fe for 33 giants in M71 using spectra obtained with the WIYN-Hydra spectrograph. Our spectroscopic analysis finds that similar to 47 Tuc and in contrast with more metal-poor GCs, M71 stars do not exhibit a strong Na-Al correlation and span a relatively narrow range in [Al/Fe], which are characteristics that GC formation models must reproduce.

  19. mRNA Transcript Abundance during Plant Growth and the Influence of Li+ Exposure

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Duff, M. C.; Kuhne, W. W.; Halverson, N. V.; Chang, C. -S.; Kitamura, E.; Hawthorn, L.; Martinez, N. E.; Stafford, C.; Milliken, C. E.; Caldwell, E. F.; et al

    2014-10-23

    Lithium (Li) toxicity in plants is, at a minimum, a function of Li+ concentration, exposure time, species and growth conditions. Most plant studies with Li+ focus on short-term acute exposures. This study examines short- and long-term effects of Li+ exposure in Arabidopsis with Li+ uptake studies and measured shoot mRNA transcript abundance levels in treated and control plants. Stress, pathogen-response and arabinogalactan protein genes were typically more up-regulated in older (chronic, low level) Li+-treatment plants and in the much younger plants from acute high-level exposures. The gene regulation behavior of high-level Li+ resembled prior studies due to its influence on:more » inositol synthesis, 1-aminocyclopropane-1-carboxylate synthases and membrane ion transport. In contrast, chronically-exposed plants had gene regulation responses that were indicative of pathogen, cold, and heavy-metal stress, cell wall degradation, ethylene production, signal transduction, and calcium-release modulation. Acute Li+ exposure phenocopies magnesium-deficiency symptoms and is associated with elevated expression of stress response genes that could lead to consumption of metabolic and transcriptional energy reserves and the dedication of more resources to cell development. In contrast, chronic Li+ exposure increases expression signal transduction genes. The identification of new Li+-sensitive genes and a gene-based “response plan” for acute and chronic Li+ exposure are delineated.« less

  20. Constraining the mSUGRA parameter space through entropy and abundance criteria

    SciTech Connect (OSTI)

    Cabral-Rosetti, Luis G.; Mondragon, Myriam; Nunez, Dario; Sussman, Roberto A.; Zavala, Jesus; Nellen, Lukas

    2007-06-19

    We explore the use of two criteria to constrain the allowed parameter space in mSUGRA models; both criteria are based in the calculation of the present density of neutralinos {chi}0 as Dark Matter in the Universe. The first one is the usual ''abundance'' criterion that requieres that present neutralino relic density complies with 0.0945 < {omega}CDMh2 < 0.1287, which are the 2{sigma} bounds according to WMAP. To calculate the relic density we use the public numerical code micrOMEGAS. The second criterion is the original idea presented in [3] that basically applies the microcanonical definition of entropy to a weakly interacting and self-gravitating gas, and then evaluate the change in entropy per particle of this gas between the freeze-out era and present day virialized structures. An 'entropy consistency' criterion emerges by comparing theoretical and empirical estimates of this entropy. One of the objetives of the work is to analyze the joint application of both criteria, already done in [3], to see if their results, using approximations for the calculations of the relic density, agree with the results coming from the exact numerical results of micrOMEGAS. The main objetive of the work is to use this method to constrain the parameter space in mSUGRA models that are inputs for the calculations of micrOMEGAS, and thus to get some bounds on the predictions for the SUSY spectra.

  1. Dynamical description of the moments of the energy distribution of fission fragments and scission of a fissile nucleus

    SciTech Connect (OSTI)

    Borunov, M. V., E-mail: bmv@opsb.ru; Nadtochy, P. N.; Adeev, G. D. [Omsk State University (Russian Federation)

    2007-11-15

    A multidimensional stochastic approach to fission dynamics on the basis of three-dimensional Langevin equations is applied systematically to calculating the first four moments of the energy distribution of fission fragments over a broad range of Coulomb parameter values (700 < Z{sup 2}/A{sup 1/3} < 1700). For the scission of a fissile nucleus into fragments, use was made of various criteria traditional in modern fission theory: the vanishing of the neck radius at the scission instant and the equality of the neck radius to about 0.3R{sub 0} at this instant. In calculating the energy distribution, both of the criteria used lead to a fairly good description of experimental data on the first two moments and to a satisfactory description of data on the third and fourth moments of the distribution. However, the quality of the description of available experimental data is insufficiently good for giving preference to any of these criteria. Within three-dimensional Langevin dynamics, it is shown that the vanishing-radius criterion leads to unexpectably good agreement with experimental data on the first four moments of the energy distribution. A modified version of one-body dissipation where the coefficient that takes into account the reduction of the wall-formula contribution was set to k{sub s} = 0.25 was used in the calculations.

  2. Aerosol Effects on Cirrus through Ice Nucleation in the Community Atmosphere Model CAM5 with a Statistical Cirrus Scheme

    SciTech Connect (OSTI)

    Wang, Minghuai; Liu, Xiaohong; Zhang, Kai; Comstock, Jennifer M.

    2014-09-01

    A statistical cirrus cloud scheme that tracks ice saturation ratio in the clear-sky and cloudy portion of a grid box separately has been implemented into NCAR CAM5 to provide a consistent treatment of ice nucleation and cloud formation. Simulated ice supersaturation and ice crystal number concentrations strongly depend on the number concentrations of heterogeneous ice nuclei (IN), subgrid temperature formulas and the number concentration of sulfate particles participating in homogeneous freezing, while simulated ice water content is insensitive to these perturbations. 1% to 10% dust particles serving as heterogeneous IN is 20 found to produce ice supersaturaiton in better agreement with observations. Introducing a subgrid temperature perturbation based on long-term aircraft observations of meso-scale motion produces a better hemispheric contrast in ice supersaturation compared to observations. Heterogeneous IN from dust particles significantly alter the net radiative fluxes at the top of atmosphere (TOA) (-0.24 to -1.59 W m-2) with a significant clear-sky longwave component (0.01 to -0.55 W m-2). Different cirrus treatments significantly perturb the net TOA anthropogenic aerosol forcing from -1.21 W m-2 to -1.54 W m-2, with a standard deviation of 0.10 W m-2. Aerosol effects on cirrus clouds exert an even larger impact on the atmospheric component of the radiative fluxes (two or three times the changes in the TOA radiative fluxes) and therefore on the hydrology cycle through the fast atmosphere response. This points to the urgent need to quantify aerosol effects on cirrus clouds through ice nucleation and how these further affect the hydrological cycle.

  3. Critical Mechanisms for the Formation of Extreme Arctic Sea-Ice Extent in the Summers of 2007 and 1996

    SciTech Connect (OSTI)

    Dong, Xiquan; Zib, Benjamin J.; Xi, Baike; Stanfield, Ryan; Deng, Yi; Zhang, Xiangdong; Lin, B.; Long, Charles N.

    2014-07-29

    A warming Arctic climate is undergoing significant e 21 nvironmental change, most evidenced by the reduction of Arctic sea-ice extent during the summer. In this study, we examine two extreme anomalies of September sea-ice extent in 2007 and 1996, and investigate the impacts of cloud fraction (CF), atmospheric precipitable water vapor (PWV), downwelling longwave flux (DLF), surface air temperature (SAT), pressure and winds on the sea-ice variation in 2007 and 1996 using both satellite-derived sea-ice products and MERRA reanalysis. The area of the Laptev, East Siberian and West Chukchi seas (70-90oN, 90-180oE) has experienced the largest variation in sea-ice extent from year-to-year and defined here as the Area Of Focus (AOF). The record low September sea-ice extent in 2007 was associated with positive anomalies 30 of CF, PWV, DLF, and SAT over the AOF. Persistent anti-cyclone positioned over the Beaufort Sea coupled with low pressure over Eurasia induced easterly zonal and southerly meridional winds. In contrast, negative CF, PWV, DLF and SAT anomalies, as well as opposite wind patterns to those in 2007, characterized the 1996 high September sea-ice extent. Through this study, we hypothesize the following positive feedbacks of clouds, water vapor, radiation and atmospheric variables on the sea-ice retreat during the summer 2007. The record low sea-ice extent during the summer 2007 is initially triggered by the atmospheric circulation anomaly. The southerly winds across the Chukchi and East Siberian seas transport warm, moist air from the north Pacific, which is not only enhancing sea-ice melt across the AOF, but also increasing clouds. The positive cloud feedback results in higher SAT and more sea-ice melt. Therefore, 40 more water vapor could be evaporated from open seas and higher SAT to form more clouds, which will enhance positive cloud feedback. This enhanced positive cloud feedback will then further increase SAT and accelerate the sea-ice retreat during the summer 2007.

  4. Thin films of the spin ice compound Ho{sub 2}Ti{sub 2}O{sub 7} (Journal

    Office of Scientific and Technical Information (OSTI)

    Article) | SciTech Connect Thin films of the spin ice compound Ho{sub 2}Ti{sub 2}O{sub 7} Citation Details In-Document Search Title: Thin films of the spin ice compound Ho{sub 2}Ti{sub 2}O{sub 7} The pyrochlore compounds Ho{sub 2}Ti{sub 2}O{sub 7} and Dy{sub 2}Ti{sub 2}O{sub 7} show an exotic form of magnetism called the spin ice state, resulting from the interplay between geometrical frustration and ferromagnetic coupling. A fascinating feature of this state is the appearance of magnetic

  5. Optimizing the performance of Ice-storage Systems in Electricity Load Management through a credit mechanism. An analytical work for Jiangsu, China

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Han, Yafeng; Shen, Bo; Hu, Huajin; Fan, Fei

    2015-01-12

    Ice-storage air-conditioning is a technique that uses ice for thermal energy storage. Replacing existing air conditioning systems with ice storage has the advantage of shifting the load from on-peak times to off-peak times that often have excess generation. However, increasing the use of ice-storage faces significant challenges in China. One major barrier is the inefficiency in the current electricity tariff structure. There is a lack of effective incentive mechanism that induces ice-storage systems from achieving optimal load-shifting results. This study presents an analysis that compares the potential impacts of ice-storage systems on load-shifting under a new credit-based incentive scheme andmore » the existing incentive arrangement in Jiangsu, China. The study indicates that by changing how ice-storage systems are incentivized in Jiangsu, load-shifting results can be improved.« less

  6. Optimizing the performance of Ice-storage Systems in Electricity Load Management through a credit mechanism. An analytical work for Jiangsu, China

    SciTech Connect (OSTI)

    Han, Yafeng; Shen, Bo; Hu, Huajin; Fan, Fei

    2015-01-12

    Ice-storage air-conditioning is a technique that uses ice for thermal energy storage. Replacing existing air conditioning systems with ice storage has the advantage of shifting the load from on-peak times to off-peak times that often have excess generation. However, increasing the use of ice-storage faces significant challenges in China. One major barrier is the inefficiency in the current electricity tariff structure. There is a lack of effective incentive mechanism that induces ice-storage systems from achieving optimal load-shifting results. This study presents an analysis that compares the potential impacts of ice-storage systems on load-shifting under a new credit-based incentive scheme and the existing incentive arrangement in Jiangsu, China. The study indicates that by changing how ice-storage systems are incentivized in Jiangsu, load-shifting results can be improved.

  7. Application of an online-coupled regional climate model, WRF-CAM5, over East Asia for examination of ice nucleation schemes. Part II. Sensitivity to heterogeneous ice nucleation parameterizations and dust emissions

    SciTech Connect (OSTI)

    Zhang, Yang; Chen, Ying; Fan, Jiwen; Leung, Lai -Yung

    2015-09-14

    Aerosol particles can affect cloud microphysical properties by serving as ice nuclei (IN). Large uncertainties exist in the ice nucleation parameterizations (INPs) used in current climate models. In this Part II paper, to examine the sensitivity of the model predictions to different heterogeneous INPs, WRF-CAM5 simulation using the INP of Niemand et al. (N12) [1] is conducted over East Asia for two full years, 2006 and 2011, and compared with simulation using the INP of Meyers et al. (M92) [2], which is the original INP used in CAM5. M92 calculates the nucleated ice particle concentration as a function of ice supersaturation, while N12 represents the nucleated ice particle concentration as a function of temperature and the number concentrations and surface areas of dust particles. Compared to M92, the WRF-CAM5 simulation with N12 produces significantly higher nucleated ice crystal number concentrations (ICNCs) in the northern domain where dust sources are located, leading to significantly higher cloud ice number and mass concentrations and ice water path, but the opposite is true in the southern domain where temperatures and moistures play a more important role in ice formation. Overall, the simulation with N12 gives lower downward shortwave radiation but higher downward longwave radiation, cloud liquid water path, cloud droplet number concentrations, and cloud optical depth. The increase in cloud optical depth and the decrease in downward solar flux result in a stronger shortwave and longwave cloud forcing, and decreases temperature at 2-m and precipitation. Changes in temperature and radiation lower surface concentrations of OH, O?, SO??, and PM2.5, but increase surface concentrations of CO, NO?, and SO? over most of the domain. By acting as cloud condensation nuclei (CCN) and IN, dust particles have different impacts on cloud water and ice number concentrations, radiation, and temperature at 2-m and precipitation depending on whether the dominant role of dust is CCN or IN. These results indicate the importance of the heterogeneous ice nucleation treatments and dust emissions in accurately simulating regional climate and air quality.

  8. SU-E-T-645: Dose Enhancement to Cell Nucleus Due to Hard Collisions of Protons with Electrons in Gold Nanospheres

    SciTech Connect (OSTI)

    Eley, J; Krishnan, S

    2014-06-15

    Purpose: The purpose of this study was to investigate the theoretical dose enhancement to a cell nucleus due to increased fluence of secondary electrons when gold nanospheres are present in the cytoplasm during proton therapy. Methods: We modeled the irradiation of prostate cancer cells using protons of variable energies when 10,000 gold nanoparticles, each with radius of 10 nm, were randomly distributed in the cytoplasm. Using simple analytical equations, we calculated the increased mean dose to the cell nucleus due to secondary electrons produced by hard collisions of 0.1, 1, 10, and 100 MeV protons with orbital electrons in gold. We only counted electrons with kinetic energy higher than 1 keV. In addition to calculating the increase in the mean dose to the cell nucleus, we also calculated the increase in local dose in the shadow, i.e., the umbra, of individual gold nanospheres due to forward scattered electrons. Results: For proton energies of 0.1, 1, 10, and 100 MeV, we calculated increases to the mean nuclear dose of 0.15, 0.09, 0.05, and 0.04%, respectively. When we considered local dose increases in the shadows of individual gold spheres, we calculated local dose increases of 5.5, 3.2, 1.9, and 1.3%, respectively. Conclusion: We found negligible, less than 0.2%, increases in the mean dose to the cell nucleus due to electrons produced by hard collisions of protons with electrons in gold nanospheres. However, we observed increases up to 5.5% in the local dose in the shadow of gold nanospheres. Considering the shadow radius of 10 nm, these local dose enhancements may have implications for slightly increased probability of clustered DNA damage when gold nanoparticles are close to the nuclear membrane.

  9. THE STAR-FORMING HISTORIES OF THE NUCLEUS, BULGE, AND INNER DISK OF NGC5102: CLUES TO THE EVOLUTION OF A NEARBY LENTICULAR GALAXY {sup ,} {sup ,}

    SciTech Connect (OSTI)

    Davidge, T. J.

    2015-01-20

    Long slit spectra recorded with the Gemini Multi-Object Spectrograph on Gemini South are used to examine the star-forming history (SFH) of the lenticular galaxy NGC5102. Structural and supplemental photometric information are obtained from archival Spitzer [3.6] images. Absorption features at blue and visible wavelengths are traced out along the minor axis to galactocentric radii ?60 arcsec (?0.9 kpc), sampling the nucleus, bulge, and disk components. Comparisons with model spectra point to luminosity-weighted metallicities that are consistent with the colors of resolved red giant branch stars in the disk. The nucleus has a luminosity-weighted age at visible wavelengths of ?1{sub ?0.1}{sup +0.2}Gyr, and the integrated light is dominated by stars that formed over a time period of only a few hundred Myr. For comparison, the luminosity-weighted ages of the bulge and disk are ?2{sub ?0.2}{sup +0.5}Gyr and 10{sub ?2}{sup +2}Gyr, respectively. The g' [3.6] colors of the nucleus and bulge are consistent with the spectroscopically based ages. In contrast to the nucleus, models that assume star-forming activity spanning many Gyr provide a better match to the spectra of the bulge and disk than simple stellar population models. Isophotes in the bulge have a disky shape, hinting that the bulge was assembled from material with significant rotational support. The SFHs of the bulge and disk are consistent with the bulge forming from the collapse of a long-lived bar, rather than from the collapse of a transient structure that formed as the result of a tidal interaction. It is thus suggested that the progenitor of NGC5102 was a barred disk galaxy that morphed into a lenticular galaxy through the buckling of its bar.

  10. Development of global sea ice 6.0 CICE configuration for the Met Office global coupled model

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Rae, J. . G. L; Hewitt, H. T.; Keen, A. B.; Ridley, J. K.; West, A. E.; Harris, C. M.; Hunke, E. C.; Walters, D. N.

    2015-03-05

    The new sea ice configuration GSI6.0, used in the Met Office global coupled configuration GC2.0, is described and the sea ice extent, thickness and volume are compared with the previous configuration and with observationally-based datasets. In the Arctic, the sea ice is thicker in all seasons than in the previous configuration, and there is now better agreement of the modelled concentration and extent with the HadISST dataset. In the Antarctic, a warm bias in the ocean model has been exacerbated at the higher resolution of GC2.0, leading to a large reduction in ice extent and volume; further work is requiredmore » to rectify this in future configurations.« less

  11. Development of the global sea ice 6.0 CICE configuration for the Met Office global coupled model

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Rae, J. G. L.; Hewitt, H. T.; Keen, A. B.; Ridley, J. K.; West, A. E.; Harris, C. M.; Hunke, E. C.; Walters, D. N.

    2015-07-24

    The new sea ice configuration GSI6.0, used in the Met Office global coupled configuration GC2.0, is described and the sea ice extent, thickness and volume are compared with the previous configuration and with observationally based data sets. In the Arctic, the sea ice is thicker in all seasons than in the previous configuration, and there is now better agreement of the modelled concentration and extent with the HadISST data set. As a result, in the Antarctic, a warm bias in the ocean model has been exacerbated at the higher resolution of GC2.0, leading to a large reduction in ice extentmore » and volume; further work is required to rectify this in future configurations.« less

  12. Development of global sea ice 6.0 CICE configuration for the Met Office global coupled model

    SciTech Connect (OSTI)

    Rae, J. . G. L; Hewitt, H. T.; Keen, A. B.; Ridley, J. K.; West, A. E.; Harris, C. M.; Hunke, E. C.; Walters, D. N.

    2015-03-05

    The new sea ice configuration GSI6.0, used in the Met Office global coupled configuration GC2.0, is described and the sea ice extent, thickness and volume are compared with the previous configuration and with observationally-based datasets. In the Arctic, the sea ice is thicker in all seasons than in the previous configuration, and there is now better agreement of the modelled concentration and extent with the HadISST dataset. In the Antarctic, a warm bias in the ocean model has been exacerbated at the higher resolution of GC2.0, leading to a large reduction in ice extent and volume; further work is required to rectify this in future configurations.

  13. Development of the global sea ice 6.0 CICE configuration for the Met Office global coupled model

    SciTech Connect (OSTI)

    Rae, J. G. L.; Hewitt, H. T.; Keen, A. B.; Ridley, J. K.; West, A. E.; Harris, C. M.; Hunke, E. C.; Walters, D. N.

    2015-07-24

    The new sea ice configuration GSI6.0, used in the Met Office global coupled configuration GC2.0, is described and the sea ice extent, thickness and volume are compared with the previous configuration and with observationally based data sets. In the Arctic, the sea ice is thicker in all seasons than in the previous configuration, and there is now better agreement of the modelled concentration and extent with the HadISST data set. As a result, in the Antarctic, a warm bias in the ocean model has been exacerbated at the higher resolution of GC2.0, leading to a large reduction in ice extent and volume; further work is required to rectify this in future configurations.

  14. Electro-Magnetic Dipole Properties of The Even-Even {sup 160}Gd Nucleus in The Spectroscopic Region

    SciTech Connect (OSTI)

    Ertugral, Filiz; Kuliev, Ali; Guliyev, Ekber

    2008-11-11

    In this study result of calculations using rotational, translational and Galilean invariant quasiparticle random-phase approximation is presented for the low lying dipole excitations in the even-even {sup 60}Gd nucleus. To make detail structure analysis for electric and magnetic dipole states, calculations carried out for both {delta}K = 1 and {delta}K = 0 branches. The analysis shows that almost all transitions with {delta}K = 1 are magnetic character in 2.4 divide 4 MeV energy interval. However, the calculations indicate the presence of a few prominent negative parity K{sup {pi}} = 1 states in the investigated energy interval, one of them with rather high E1 strength B(E1) = 7.1{center_dot}10{sup -3} e{sup 2} fm{sup 2} at energy 3.2 MeV. Calculated M1 dipole strength of the scissors mode K{sup {pi}} = 1{sup +} excitations clustered in two groups around 2.7 and 3.3 MeV. A similar situation arises for the experimentally obtained states two bumps around {omega}{sub i} = 2.7 MeV and {omega}{sub i} = 3.3 MeV. It has been shown that main part of spin-1 states, observed at energy 2.4 divide 4 MeV in {sup 160}Gd may be attributed to have M1 character and may be interpreted as main fragments of the scissors mode. However, it is apparent that the experimental data exceeds the calculation results for the summed B(M1) by a factor of 1.13 for M1 transitions.

  15. DRIVING OUTFLOWS WITH RELATIVISTIC JETS AND THE DEPENDENCE OF ACTIVE GALACTIC NUCLEUS FEEDBACK EFFICIENCY ON INTERSTELLAR MEDIUM INHOMOGENEITY

    SciTech Connect (OSTI)

    Wagner, A. Y.; Umemura, M.; Bicknell, G. V.

    2012-10-01

    We examine the detailed physics of the feedback mechanism by relativistic active galactic nucleus (AGN) jets interacting with a two-phase fractal interstellar medium (ISM) in the kpc-scale core of galaxies using 29 three-dimensional grid-based hydrodynamical simulations. The feedback efficiency, as measured by the amount of cloud dispersal generated by the jet-ISM interactions, is sensitive to the maximum size of clouds in the fractal cloud distribution but not to their volume filling factor. Feedback ceases to be efficient for Eddington ratios P{sub jet}/L{sub edd} {approx}< 10{sup -4}, although systems with large cloud complexes {approx}> 50 pc require jets of Eddington ratio in excess of 10{sup -2} to disperse the clouds appreciably. Based on measurements of the bubble expansion rates in our simulations, we argue that sub-grid AGN prescriptions resulting in negative feedback in cosmological simulations without a multi-phase treatment of the ISM are good approximations if the volume filling factor of warm-phase material is less than 0.1 and the cloud complexes are smaller than {approx}25 pc. We find that the acceleration of the dense embedded clouds is provided by the ram pressure of the high-velocity flow through the porous channels of the warm phase, flow that has fully entrained the shocked hot-phase gas it has swept up, and is additionally mass loaded by ablated cloud material. This mechanism transfers 10% to 40% of the jet energy to the cold and warm gas, accelerating it within a few 10 to 100 Myr to velocities that match those observed in a range of high- and low-redshift radio galaxies hosting powerful radio jets.

  16. A Study of the Optical Properties of Ice Crystals with Black Carbon Inclusions

    SciTech Connect (OSTI)

    Arienti, Marco; Yang, Xiaoyuan; Kopacz, Adrian M; Geier, Manfred

    2015-09-01

    The report focu ses on the modification of the optical properties of ice crystals due to atmospheric black car bon (BC) contamination : the objective is to advance the predictive capabilities of climate models through an improved understanding of the radiative properties of compound particles . The shape of the ice crystal (as commonly found in cirrus clouds and cont rails) , the volume fraction of the BC inclusion , and its location inside the crystal are the three factors examined in this study. In the multiscale description of this problem, where a small absorbing inclusion modifies the optical properties of a much la rger non - absorbing particle, state - of - the - art discretization techniques are combined to provide the best compromise of flexibility and accuracy over a broad range of sizes .

  17. A Compact, Backscattering Deplolarization Cloud Spectrometer for Ice and Water Discrimination

    SciTech Connect (OSTI)

    Thomson, David

    2014-05-15

    This project was to develop a compact optical particle spectrometer, small enough for operation on UAVS, that measures the optical diameter of cloud hydrometeors and differentiates their water phase (liquid or solid). To reach this goal, a work plan was laid out that would complete three objectives: 1) Evaluation of designs for an optical particle spectrometer that measures the component of light backscattered at two polarization angles. 2) Testing of selected designs on an optical bench. 3) Construction and preliminary testing of a prototype instrument based on the selected, optimum design. A protoype instrument was developed and tested in an icing wind tunnel where the results showed good measurement of cloud droplets and ice particles.

  18. Ocean-ice/oil-weathering computer program user's manual. Final report

    SciTech Connect (OSTI)

    Kirstein, B.E.; Redding, R.T.

    1987-10-01

    The ocean-ice/oil-weathering code is written in FORTRAN as a series of stand-alone subroutines that can easily be installed on most any computer. All of the trial-and-error routines, integration routines, and other special routines are written in the code so that nothing more than the normal system functions such as EXP are required. The code is user-interactive and requests input by prompting questions with suggested input. Therefore, the user can actually learn about the nature of crude oil and oil weathering by using this code. The ocean-ice oil-weathering model considers the following weathering processes: evaporation; dispersion (oil into water); moussee (water into oil); and spreading; These processes are used to predict the mass balance and composition of oil remaining in the slick as a function of time and environmental parameters.

  19. Water droplet behavior on superhydrophobic SiO{sub 2} nanocomposite films during icing/deicing cycles

    SciTech Connect (OSTI)

    Lazauskas, A.; Guobien?, A.; Prosy?evas, I.; Baltruaitis, V.; Grigali?nas, V.; Narmontas, P.; Baltrusaitis, J.

    2013-08-15

    This work investigates water droplet behavior on superhydrophobic (water contact angle value of 162 1) SiO{sub 2} nanocomposite films subjected to repetitive icing/deicing treatments, changes in SiO{sub 2} nanocomposite film surface morphology and their non-wetting characteristics. During the experiment, water droplets on SiO{sub 2} nanocomposite film surface are subjected to a series of icing and deicing cycles in a humid (? 70% relative humidity) atmosphere and the resulting morphological changes are monitored and characterized using atomic force microscopy (AFM) and contact angle measurements. Our data show that the formation of the frozen or thawed water droplet, with no further shape change, on superhydrophobic SiO{sub 2} nanocomposite film, is obtained faster within each cycle as the number of the icing/deicing cycles increases. After 10 icing and deicing cycles, the superhydrophobic SiO{sub 2} nanocomposite film had a water contact angle value of 146 2 which is effectively non-superhydrophobic. AFM analysis showed that the superhydrophobic SiO{sub 2} nanocomposite film surface area under the water droplet undergoes gradual mechanical damage during the repetitive icing/deicing cycles. We propose a possible mechanism of the morphological changes to the film surface that take place during the consecutive icing/deicing experiments. - Highlights: Superhydrophobic film is subjected to repetitive icing/deicing treatments. Water droplet shape transition is recorded and characterized thereafter. Atomic force microscopy and contact angle measurements are performed. The surface undergoes gradual mechanical damage during repetitive icing/deicing. Mechanism for the observed surface morphological changes is suggested.

  20. Intercomparison of Large-eddy Simulations of Arctic Mixed-phase Clouds: Importance of Ice Size Distribution Assumptions

    SciTech Connect (OSTI)

    Ovchinnikov, Mikhail; Ackerman, Andrew; Avramov, Alex; Cheng, Anning; Fan, Jiwen; Fridlind, Ann; Ghan, Steven J.; Harrington, Jerry Y.; Hoose, Corinna; Korolev, Alexei; McFarquhar, Greg; Morrison, H.; Paukert, Marco; Savre, Julien; Shipway, Ben; Shupe, Matthew D.; Solomon, Amy; Sulia, Kara

    2014-03-14

    Large-eddy simulations of mixed-phase Arctic clouds by 11 different models are analyzed with the goal of improving understanding and model representation of processes controlling the evolution of these clouds. In a case based on observations from the Indirect and Semi-Direct Aerosol Campaign (ISDAC), it is found that ice number concentration, Ni, exerts significant influence on the cloud structure. Increasing Ni leads to a substantial reduction in liquid water path (LWP) and potential cloud dissipation, in agreement with earlier studies. By comparing simulations with the same microphysics coupled to different dynamical cores as well as the same dynamics coupled to different microphysics schemes, it is found that the ice water path (IWP) is mainly controlled by ice microphysics, while the inter-model differences in LWP are largely driven by physics and numerics of the dynamical cores. In contrast to previous intercomparisons, all models here use the same ice particle properties (i.e., mass-size, mass-fall speed, and mass-capacitance relationships) and a common radiation parameterization. The constrained setup exposes the importance of ice particle size distributions (PSD) in influencing cloud evolution. A clear separation in LWP and IWP predicted by models with bin and bulk microphysical treatments is documented and attributed primarily to the assumed shape of ice PSD used in bulk schemes. Compared to the bin schemes that explicitly predict the PSD, schemes assuming exponential ice PSD underestimate ice growth by vapor deposition and overestimate mass-weighted fall speed leading to an underprediction of IWP by a factor of two in the considered case.

  1. Hydrogen Materials Compatibility for the H-ICE | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    1 DOE Hydrogen and Fuel Cells Program, and Vehicle Technologies Program Annual Merit Review and Peer Evaluation PDF icon pm019_pitman_2011_p.pdf More Documents & Publications Hydrogen Materials Compatibility for the H-ICE Vehicle Technologies Office Merit Review 2014: Design Optimization of Piezoceramic Multilayer Actuators for Heavy Duty Diesel Engine Fuel Injectors Design Optimization of Piezoceramic Multilayer Actuators for Heavy Duty Diesel Engine Fuel Injectors

  2. Freezing a Droplet to Stop the Ice | U.S. DOE Office of Science (SC)

    Office of Science (SC) Website

    Freezing a Droplet to Stop the Ice Advanced Scientific Computing Research (ASCR) ASCR Home About Research Facilities Science Highlights Benefits of ASCR Funding Opportunities Advanced Scientific Computing Advisory Committee (ASCAC) Community Resources Contact Information Advanced Scientific Computing Research U.S. Department of Energy SC-21/Germantown Building 1000 Independence Ave., SW Washington, DC 20585 P: (301) 903-7486 F: (301) 903-4846 E: Email Us More Information » 08.01.15 Freezing a

  3. Greenland Ice Sheet "Sliding" a Small Contributor to Future Sea-Level

    Office of Science (SC) Website

    Rise | U.S. DOE Office of Science (SC) Greenland Ice Sheet "Sliding" a Small Contributor to Future Sea-Level Rise Advanced Scientific Computing Research (ASCR) ASCR Home About Research Facilities Science Highlights Benefits of ASCR Funding Opportunities Advanced Scientific Computing Advisory Committee (ASCAC) Community Resources Contact Information Advanced Scientific Computing Research U.S. Department of Energy SC-21/Germantown Building 1000 Independence Ave., SW Washington, DC

  4. Greenland Ice Sheet "Sliding" a Small Contributor to Future Sea-Level

    Office of Science (SC) Website

    Rise | U.S. DOE Office of Science (SC) Greenland Ice Sheet "Sliding" a Small Contributor to Future Sea-Level Rise Biological and Environmental Research (BER) BER Home About Research Facilities Science Highlights Searchable Archive of BER Highlights External link Benefits of BER Funding Opportunities Biological & Environmental Research Advisory Committee (BERAC) Community Resources Contact Information Biological and Environmental Research U.S. Department of Energy

  5. New Method Relates Greenland Ice Sheet Changes to Sea-Level Rise | U.S. DOE

    Office of Science (SC) Website

    Office of Science (SC) New Method Relates Greenland Ice Sheet Changes to Sea-Level Rise Biological and Environmental Research (BER) BER Home About Research Facilities Science Highlights Searchable Archive of BER Highlights External link Benefits of BER Funding Opportunities Biological & Environmental Research Advisory Committee (BERAC) Community Resources Contact Information Biological and Environmental Research U.S. Department of Energy SC-23/Germantown Building 1000 Independence Ave.,

  6. Radiokrypton Dating Identifies Ancient Antarctic Ice | U.S. DOE Office of

    Office of Science (SC) Website

    Science (SC) Radiokrypton Dating Identifies Ancient Antarctic Ice Nuclear Physics (NP) NP Home About Research Facilities Science Highlights Benefits of NP Funding Opportunities Nuclear Science Advisory Committee (NSAC) Community Resources Contact Information Nuclear Physics U.S. Department of Energy SC-26/Germantown Building 1000 Independence Ave., SW Washington, DC 20585 P: (301) 903-3613 F: (301) 903-3833 E: Email Us More Information » 11.01.14 Radiokrypton Dating Identifies Ancient

  7. Magnetic vortex crystal formation in the antidot complement of square artificial spin ice

    SciTech Connect (OSTI)

    Araujo, C. I. L. de Silva, R. C.; Ribeiro, I. R. B.; Nascimento, F. S.; Felix, J. F.; Ferreira, S. O.; Moura-Melo, W. A.; Pereira, A. R.; Ml, L. A. S.

    2014-03-03

    We have studied ferromagnetic nickel thin films patterned with square lattices of elongated antidots that are negative analogues of square artificial spin ice. Micromagnetic simulations and direct current magnetic moment measurements reveal in-plane anisotropy of the magnetic hysteresis loops, and the formation of a dense array of magnetic vortices with random polarization and chirality. These multiply-connected antidot arrays could be superior to lattices of disconnected nanodisks for investigations of vortex switching by applied electric current.

  8. Molecular origin of the difference in the HOH bend of the IR spectra between liquid water and ice

    SciTech Connect (OSTI)

    Imoto, Sho; Xantheas, Sotiris S.; Saito, Shinji

    2013-02-07

    The intensity of the HOH bend in the IR spectrum of ice is significantly smaller than the corresponding one in liquid water. This difference in the IR intensities of the HOH bend in the two systems is investigated using MD simulations with the flexible, polarizable, ab-initio based TTM3-F model for water, a potential that correctly reproduces the experimentally observed increase of the HOH bend in liquid water and ice from the water monomer value. We have identified two factors that are responsible for the difference in the intensity of the HOH bend in liquid water and ice: (i) the decrease of the intensity of the HOH bend in ice caused by the strong anti-correlation between the permanent dipole moment of a molecule and the induced dipole moment of a neighboring hydrogen bond acceptor molecule and (ii) the weakening of this anti-correlation by the disordered hydrogen bond network in liquid water. The presence of the anti-correlation in ice is further confirmed by ab initio electronic structure calculations of water pentamer clusters extracted from the trajectories of the MD simulations for ice and liquid water.

  9. Searching for MeV-scale gauge bosons with IceCube

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    DiFranzo, Anthony; Hooper, Dan

    2015-11-05

    Light gauge bosons can lead to resonant interactions between high-energy astrophysical neutrinos and the cosmic neutrino background. We study this possibility in detail, considering the ability of IceCube to probe such scenarios. We also find the most dramatic effects in models with a very light Z' (mZ'≲10 MeV), which can induce a significant absorption feature at Eν~5–10 TeV×(mZ'/MeV)2. In the case of the inverted hierarchy and a small sum of neutrino masses, such a light Z' can result in a broad and deep spectral feature at ~0.1–10 PeV×(mZ'/MeV)2. Current IceCube data already excludes this case for a Z' lighter thanmore » a few MeV and couplings greater than g~10-4. Furthermore, we emphasize that the ratio of neutrino flavors observed by IceCube can be used to further increase their sensitivity to Z' models and to other exotic physics scenarios.« less

  10. Nanocluster building blocks of artificial square spin ice: Stray-field studies of thermal dynamics

    SciTech Connect (OSTI)

    Pohlit, Merlin Porrati, Fabrizio; Huth, Michael; Müller, Jens

    2015-05-07

    We present measurements of the thermal dynamics of a Co-based single building block of an artificial square spin ice fabricated by focused electron-beam-induced deposition. We employ micro-Hall magnetometry, an ultra-sensitive tool to study the stray field emanating from magnetic nanostructures, as a new technique to access the dynamical properties during the magnetization reversal of the spin-ice nanocluster. The obtained hysteresis loop exhibits distinct steps, displaying a reduction of their “coercive field” with increasing temperature. Therefore, thermally unstable states could be repetitively prepared by relatively simple temperature and field protocols allowing one to investigate the statistics of their switching behavior within experimentally accessible timescales. For a selected switching event, we find a strong reduction of the so-prepared states' “survival time” with increasing temperature and magnetic field. Besides the possibility to control the lifetime of selected switching events at will, we find evidence for a more complex behavior caused by the special spin ice arrangement of the macrospins, i.e., that the magnetic reversal statistically follows distinct “paths” most likely driven by thermal perturbation.

  11. COMET C/2011 W3 (LOVEJOY): ORBIT DETERMINATION, OUTBURSTS, DISINTEGRATION OF NUCLEUS, DUST-TAIL MORPHOLOGY, AND RELATIONSHIP TO NEW CLUSTER OF BRIGHT SUNGRAZERS

    SciTech Connect (OSTI)

    Sekanina, Zdenek; Chodas, Paul W. E-mail: Paul.W.Chodas@jpl.nasa.gov

    2012-10-01

    We describe the physical and orbital properties of C/2011 W3. After surviving perihelion passage, the comet was observed to undergo major physical changes. The permanent loss of the nuclear condensation and the formation of a narrow spine tail were observed first at Malargue, Argentina, on December 20 and then systematically at Siding Spring, Australia. The process of disintegration culminated with a terminal fragmentation event on December 17.6 UT. The postperihelion dust tail, observed for {approx}3 months, was the product of activity over <2 days. The nucleus' breakup and crumbling were probably caused by thermal stress due to the penetration of the intense heat pulse deep into the nucleus' interior after perihelion. The same mechanism may be responsible for cascading fragmentation of sungrazers at large heliocentric distances. The delayed response to the hostile environment in the solar corona is at odds with the rubble-pile model, since the residual mass of the nucleus, estimated at {approx}10{sup 12} g (equivalent to a sphere 150-200 m across) just before the terminal event, still possessed nontrivial cohesive strength. The high production rates of atomic oxygen, observed shortly after perihelion, are compatible with a subkilometer-sized nucleus. The spine tail-the product of the terminal fragmentation-was a synchronic feature, whose brightest part contained submillimeter-sized dust grains, released at velocities of up to 30 m s{sup -1}. The loss of the nuclear condensation prevented an accurate orbital-period determination by traditional techniques. Since the missing nucleus must have been located on the synchrone, whose orientation and sunward tip have been measured, we compute the astrometric positions of this missing nucleus as the coordinates of the points of intersection of the spine tail's axis with the lines of forced orbital-period variation, derived from the orbital solutions based on high-quality preperihelion astrometry from the ground. The resulting orbit gives 698 {+-} 2 yr for the osculating orbital period, showing that C/2011 W3 is the first member of the expected new, 21st-century cluster of bright Kreutz-system sungrazers, whose existence was predicted by these authors in 2007. From the spine tail's evolution, we determine that its measured tip, populated by dust particles 1-2 mm in diameter, receded antisunward from the computed position of the missing nucleus. The bizarre appearance of the comet's dust tail in images taken only hours after perihelion with the coronagraphs on board the SOHO and STEREO spacecraft is readily understood. The disconnection of the comet's head from the tail released before perihelion and an apparent activity attenuation near perihelion have a common cause-sublimation of all dust at heliocentric distances smaller than about 1.8 solar radii. The tail's brightness is strongly affected by forward scattering of sunlight by dust. From an initially broad range of particle sizes, the grains that were imaged the longest had a radiation-pressure parameter {beta} {approx_equal} 0.6, diagnostic of submicron-sized silicate grains and consistent with the existence of the dust-free zone around the Sun. The role and place of C/2011 W3 in the hierarchy of the Kreutz system and its genealogy via a 14th-century parent suggest that it is indirectly related to the celebrated sungrazer X/1106 C1, which, just as the first-generation parent of C/2011 W3, split from a common predecessor during the previous return to perihelion.

  12. Application of an online-coupled regional climate model, WRF-CAM5, over East Asia for examination of ice nucleation schemes. Part II. Sensitivity to heterogeneous ice nucleation parameterizations and dust emissions

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Zhang, Yang; Chen, Ying; Fan, Jiwen; Leung, Lai -Yung

    2015-09-14

    Aerosol particles can affect cloud microphysical properties by serving as ice nuclei (IN). Large uncertainties exist in the ice nucleation parameterizations (INPs) used in current climate models. In this Part II paper, to examine the sensitivity of the model predictions to different heterogeneous INPs, WRF-CAM5 simulation using the INP of Niemand et al. (N12) [1] is conducted over East Asia for two full years, 2006 and 2011, and compared with simulation using the INP of Meyers et al. (M92) [2], which is the original INP used in CAM5. M92 calculates the nucleated ice particle concentration as a function of icemore » supersaturation, while N12 represents the nucleated ice particle concentration as a function of temperature and the number concentrations and surface areas of dust particles. Compared to M92, the WRF-CAM5 simulation with N12 produces significantly higher nucleated ice crystal number concentrations (ICNCs) in the northern domain where dust sources are located, leading to significantly higher cloud ice number and mass concentrations and ice water path, but the opposite is true in the southern domain where temperatures and moistures play a more important role in ice formation. Overall, the simulation with N12 gives lower downward shortwave radiation but higher downward longwave radiation, cloud liquid water path, cloud droplet number concentrations, and cloud optical depth. The increase in cloud optical depth and the decrease in downward solar flux result in a stronger shortwave and longwave cloud forcing, and decreases temperature at 2-m and precipitation. Changes in temperature and radiation lower surface concentrations of OH, O₃, SO₄²⁻, and PM2.5, but increase surface concentrations of CO, NO₂, and SO₂ over most of the domain. By acting as cloud condensation nuclei (CCN) and IN, dust particles have different impacts on cloud water and ice number concentrations, radiation, and temperature at 2-m and precipitation depending on whether the dominant role of dust is CCN or IN. These results indicate the importance of the heterogeneous ice nucleation treatments and dust emissions in accurately simulating regional climate and air quality.« less

  13. Effects of ion abundances on electromagnetic ion cyclotron wave growth rate in the vicinity of the plasmapause

    SciTech Connect (OSTI)

    Henning, F. D. Mace, R. L.

    2014-04-15

    Electromagnetic ion cyclotron (EMIC) waves in multi-ion species plasmas propagate in branches. Except for the branch corresponding to the heaviest ion species, which has only a resonance at its gyrofrequency, these branches are bounded below by a cutoff frequency and above by a resonant gyrofrequency. The condition for wave growth is determined by the thermal anisotropies of each ion species, j, which sets an upper bound, ?{sub j}{sup ?}, on the wave frequency below which that ion species contributes positively to the growth rate. It follows that the relative positions of the cutoffs and the critical frequencies ?{sub j}{sup ?} play a crucial role in determining whether a particular wave branch will be unstable. The effect of the magnetospheric ion abundances on the growth rate of each branch of the EMIC instability in a model where all the ion species have kappa velocity distributions is investigated by appealing to the above ideas. Using the variation of the cutoff frequencies predicted by cold plasma theory as a guide, optimal ion abundances that maximise the EMIC instability growth rate are sought. When the ring current is comprised predominantly of H{sup +} ions, all branches of the EMIC wave are destabilised, with the proton branch having the maximum growth rate. When the O{sup +} ion abundance in the ring current is increased, a decrease in the growth rate of the proton branch and cyclotron damping of the helium branch are observed. The oxygen branch, on the other hand, experiences an increase in the maximum growth rate with an increase in the O{sup +} ion abundance. When the ring current is comprised predominantly of He{sup +} ions, only the helium and oxygen branches of the EMIC wave are destabilised, with the helium branch having the maximum growth rate.

  14. THIRD COMPONENT SEARCH AND ABUNDANCES OF THE VERY DUSTY SHORT-PERIOD BINARY BD +20 Degree-Sign 307

    SciTech Connect (OSTI)

    Fekel, Francis C.; Cordero, Maria J.; Galicher, Raphael; Zuckerman, B.; Melis, Carl; Weinberger, Alycia J. E-mail: majocord@indiana.edu E-mail: ben@astro.ucla.edu E-mail: weinberger@dtm.ciw.edu

    2012-04-10

    We have obtained near-infrared adaptive optics imaging and collected additional radial velocity observations to search for a third component in the extremely dusty short-period binary system BD +20 Degree-Sign 307. Our image shows no evidence for a third component at separations greater than 19 AU. Our four seasons of radial velocities have a constant center-of-mass velocity and are consistent with the systemic velocities determined at two earlier epochs. Thus, the radial velocities also provide no support for a third component. Unfortunately, the separation domains covered by our imaging and radial velocity results do not overlap. Thus, we examined the parameters for possible orbits of a third component that could have been missed by our current observations. With our velocities we determined improved circular orbital elements for the 3.4 day double-lined binary. We also performed a spectroscopic abundance analysis of the short-period binary components and conclude that the stars are a mid- and a late-F dwarf. We find that the iron abundances of both components, [Fe/H] = 0.15, are somewhat greater than the solar value and comparable to that of stars in the Hyades. Despite the similarity of the binary components, the lithium abundances of the two stars are very unequal. The primary has log {epsilon} (Li) = 2.72, while in the secondary log {epsilon} (Li) {<=}1.46, which corresponds to a difference of at least a factor of 18. The very disparate lithium abundances in very similar stars make it impossible to ascribe a single age to them. While the system is likely at least 1 Gyr old, it may well be as old as the Sun.

  15. NON-LOCAL THERMODYNAMICAL EQUILIBRIUM EFFECTS ON THE IRON ABUNDANCE OF ASYMPTOTIC GIANT BRANCH STARS IN 47 TUCANAE

    SciTech Connect (OSTI)

    Lapenna, E.; Mucciarelli, A.; Lanzoni, B.; Ferraro, F. R.; Dalessandro, E.; Massari, D.

    2014-12-20

    We present the iron abundance of 24 asymptotic giant branch (AGB) stars, members of the globular cluster 47 Tucanae, obtained with high-resolution spectra collected with the FEROS spectrograph at the MPG/ESO 2.2 m Telescope. We find that the iron abundances derived from neutral lines (with a mean value [Fe I/H]=0.94 0.01, ? = 0.08 dex) are systematically lower than those derived from single ionized lines ([Fe II/H] =0.83 0.01, ? = 0.05 dex). Only the latter are in agreement with those obtained for a sample of red giant branch (RGB) cluster stars, for which the Fe I and Fe II lines provide the same iron abundance. This finding suggests that non-local thermodynamical equilibrium (NLTE) effects driven by overionization mechanisms are present in the atmosphere of AGB stars and significantly affect the Fe I lines while leaving Fe II features unaltered. On the other hand, the very good ionization equilibrium found for RGB stars indicates that these NLTE effects may depend on the evolutionary stage. We discuss the impact of this finding on both the chemical analysis of AGB stars and on the search for evolved blue stragglers.

  16. Natural abundance 17O DNP two-dimensional and surface-enhanced NMR spectroscopy

    SciTech Connect (OSTI)

    Perras, Frdric A.; Kobayashi, Takeshi; Pruski, Marek

    2015-06-22

    Due to its extremely low natural abundance and quadrupolar nature, the 17O nuclide is very rarely used for spectroscopic investigation of solids by NMR without isotope enrichment. Additionally, the applicability of dynamic nuclear polarization (DNP), which leads to sensitivity enhancements of 2 orders of magnitude, to 17O is wrought with challenges due to the lack of spin diffusion and low polarization transfer efficiency from 1H. Here, we demonstrate new DNP-based measurements that extend 17O solid-state NMR beyond its current capabilities. The use of the PRESTO technique instead of conventional 1H17O cross-polarization greatly improves the sensitivity and enables the facile measurement of undistorted line shapes and two-dimensional 1H17O HETCOR NMR spectra as well as accurate internuclear distance measurements at natural abundance. This was applied for distinguishing hydrogen-bonded and lone 17O sites on the surface of silica gel; the one-dimensional spectrum of which could not be used to extract such detail. As a result, this greatly enhanced sensitivity has enabled, for the first time, the detection of surface hydroxyl sites on mesoporous silica at natural abundance, thereby extending the concept of DNP surface-enhanced NMR spectroscopy to the 17O nuclide.

  17. TORUS AND ACTIVE GALACTIC NUCLEUS PROPERTIES OF NEARBY SEYFERT GALAXIES: RESULTS FROM FITTING INFRARED SPECTRAL ENERGY DISTRIBUTIONS AND SPECTROSCOPY

    SciTech Connect (OSTI)

    Alonso-Herrero, Almudena; Ramos Almeida, Cristina; Mason, Rachel; Asensio Ramos, Andres; Rodriguez Espinosa, Jose Miguel; Perez-Garcia, Ana M.; Roche, Patrick F.; Levenson, Nancy A.; Elitzur, Moshe; Packham, Christopher; Young, Stuart; Diaz-Santos, Tanio

    2011-08-01

    We used the CLUMPY torus models and a Bayesian approach to fit the infrared spectral energy distributions and ground-based high angular resolution mid-infrared spectroscopy of 13 nearby Seyfert galaxies. This allowed us to put tight constraints on torus model parameters such as the viewing angle i, the radial thickness of the torus Y, the angular size of the cloud distribution {sigma}{sub torus}, and the average number of clouds along radial equatorial rays N{sub 0}. We found that the viewing angle i is not the only parameter controlling the classification of a galaxy into type 1 or type 2. In principle, type 2s could be viewed at any viewing angle i as long as there is one cloud along the line of sight. A more relevant quantity for clumpy media is the probability for an active galactic nucleus (AGN) photon to escape unabsorbed. In our sample, type 1s have relatively high escape probabilities, P{sub esc} {approx} 12%-44%, while type 2s, as expected, tend to have very low escape probabilities. Our fits also confirmed that the tori of Seyfert galaxies are compact with torus model radii in the range 1-6 pc. The scaling of the models to the data also provided the AGN bolometric luminosities L{sub bol}(AGN), which were found to be in good agreement with estimates from the literature. When we combined our sample of Seyfert galaxies with a sample of PG quasars from the literature to span a range of L{sub bol}(AGN) {approx} 10{sup 43}-10{sup 47} erg s{sup -1}, we found plausible evidence of the receding torus. That is, there is a tendency for the torus geometrical covering factor to be lower (f{sub 2} {approx} 0.1-0.3) at high AGN luminosities than at low AGN luminosities (f{sub 2} {approx} 0.9-1 at {approx}10{sup 43}-10{sup 44} erg s{sup -1}). This is because at low AGN luminosities the tori appear to have wider angular sizes (larger {sigma}{sub torus}) and more clouds along radial equatorial rays. We cannot, however, rule out the possibility that this is due to contamination by extended dust structures not associated with the dusty torus at low AGN luminosities, since most of these in our sample are hosted in highly inclined galaxies.

  18. Application of an online-coupled regional climate model, WRF-CAM5, over East Asia for examination of ice nucleation schemes: Part I. Comprehensive model evaluation and trend analysis for 2006 and 2011

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Chen, Ying; Zhang, Yang; Fan, Jiwen; Leung, Lai -Yung; Zhang, Qiang; He, Kebin

    2015-08-18

    Online-coupled climate and chemistry models are necessary to realistically represent the interactions between climate variables and chemical species and accurately simulate aerosol direct and indirect effects on cloud, precipitation, and radiation. In this Part I of a two-part paper, simulations from the Weather Research and Forecasting model coupled with the physics package of Community Atmosphere Model (WRF-CAM5) are conducted with the default heterogeneous ice nucleation parameterization over East Asia for two full years: 2006 and 2011. A comprehensive model evaluation is performed using satellite and surface observations. The model shows an overall acceptable performance for major meteorological variables at themore » surface and in the boundary layer, as well as column variables (e.g., precipitation, cloud fraction, precipitating water vapor, downward longwave and shortwave radiation). Moderate to large biases exist for cloud condensation nuclei over oceanic areas, cloud variables (e.g., cloud droplet number concentration, cloud liquid and ice water paths, cloud optical depth, longwave and shortwave cloud forcing). These biases indicate a need to improve the model treatments for cloud processes, especially cloud droplets and ice nucleation, as well as to reduce uncertainty in the satellite retrievals. The model simulates well the column abundances of chemical species except for column SO2 but relatively poor for surface concentrations of several species such as CO, NO2, SO2, PM2.5, and PM10. Several reasons could contribute to the underestimation of major chemical species in East Asia including underestimations of anthropogenic emissions and natural dust emissions, uncertainties in the spatial and vertical distributions of the anthropogenic emissions, as well as biases in meteorological, radiative, and cloud predictions. Despite moderate to large biases in the chemical predictions, the model performance is generally consistent with or even better than that reported for East Asia with only a few exceptions. The model generally reproduces the observed seasonal variations and the difference between 2006 and 2011 for most variables or chemical species. Overall, these results demonstrate promising skills of WRF-CAM5 for long-term simulations at a regional scale and suggest several areas of potential improvements.« less

  19. Application of an online-coupled regional climate model, WRF-CAM5, over East Asia for examination of ice nucleation schemes: Part I. Comprehensive model evaluation and trend analysis for 2006 and 2011

    SciTech Connect (OSTI)

    Chen, Ying; Zhang, Yang; Fan, Jiwen; Leung, Lai -Yung; Zhang, Qiang; He, Kebin

    2015-08-18

    Online-coupled climate and chemistry models are necessary to realistically represent the interactions between climate variables and chemical species and accurately simulate aerosol direct and indirect effects on cloud, precipitation, and radiation. In this Part I of a two-part paper, simulations from the Weather Research and Forecasting model coupled with the physics package of Community Atmosphere Model (WRF-CAM5) are conducted with the default heterogeneous ice nucleation parameterization over East Asia for two full years: 2006 and 2011. A comprehensive model evaluation is performed using satellite and surface observations. The model shows an overall acceptable performance for major meteorological variables at the surface and in the boundary layer, as well as column variables (e.g., precipitation, cloud fraction, precipitating water vapor, downward longwave and shortwave radiation). Moderate to large biases exist for cloud condensation nuclei over oceanic areas, cloud variables (e.g., cloud droplet number concentration, cloud liquid and ice water paths, cloud optical depth, longwave and shortwave cloud forcing). These biases indicate a need to improve the model treatments for cloud processes, especially cloud droplets and ice nucleation, as well as to reduce uncertainty in the satellite retrievals. The model simulates well the column abundances of chemical species except for column SO2 but relatively poor for surface concentrations of several species such as CO, NO2, SO2, PM2.5, and PM10. Several reasons could contribute to the underestimation of major chemical species in East Asia including underestimations of anthropogenic emissions and natural dust emissions, uncertainties in the spatial and vertical distributions of the anthropogenic emissions, as well as biases in meteorological, radiative, and cloud predictions. Despite moderate to large biases in the chemical predictions, the model performance is generally consistent with or even better than that reported for East Asia with only a few exceptions. The model generally reproduces the observed seasonal variations and the difference between 2006 and 2011 for most variables or chemical species. Overall, these results demonstrate promising skills of WRF-CAM5 for long-term simulations at a regional scale and suggest several areas of potential improvements.

  20. Final scientific report for DOE award title: Improving the Representation of Ice Sedimentation Rates in Global Climate Models

    SciTech Connect (OSTI)

    Mitchell, David L.

    2013-09-05

    It is well known that cirrus clouds play a major role in regulating the earth’s climate, but the details of how this works are just beginning to be understood. This project targeted the main property of cirrus clouds that influence climate processes; the ice fall speed. That is, this project improves the representation of the mass-weighted ice particle fall velocity, Vm, in climate models, used to predict future climate on global and regional scales. Prior to 2007, the dominant sizes of ice particles in cirrus clouds were poorly understood, making it virtually impossible to predict how cirrus clouds interact with sunlight and thermal radiation. Due to several studies investigating the performance of optical probes used to measure the ice particle size distribution (PSD), as well as the remote sensing results from our last ARM project, it is now well established that the anomalously high concentrations of small ice crystals often reported prior to 2007 were measurement artifacts. Advances in the design and data processing of optical probes have greatly reduced these ice artifacts that resulted from the shattering of ice particles on the probe tips and/or inlet tube, and PSD measurements from one of these improved probes (the 2-dimensional Stereo or 2D-S probe) are utilized in this project to parameterize Vm for climate models. Our original plan in the proposal was to parameterize the ice PSD (in terms of temperature and ice water content) and ice particle mass and projected area (in terms of mass- and area-dimensional power laws or m-D/A-D expressions) since these are the microphysical properties that determine Vm, and then proceed to calculate Vm from these parameterized properties. But the 2D-S probe directly measures ice particle projected area and indirectly estimates ice particle mass for each size bin. It soon became apparent that the original plan would introduce more uncertainty in the Vm calculations than simply using the 2D-S measurements to directly calculate Vm. By calculating Vm directly from the measured PSD, ice particle projected area and estimated mass, more accurate estimates of Vm are obtained. These Vm values were then parameterized for climate models by relating them to (1) sampling temperature and ice water content (IWC) and (2) the effective diameter (De) of the ice PSD. Parameterization (1) is appropriate for climate models having single-moment microphysical schemes whereas (2) is appropriate for double-moment microphysical schemes and yields more accurate Vm estimates. These parameterizations were developed for tropical cirrus clouds, Arctic cirrus, mid-latitude synoptic cirrus and mid-latitude anvil cirrus clouds based on field campaigns in these regions. An important but unexpected result of this research was the discovery of microphysical evidence indicating the mechanisms by which ice crystals are produced in cirrus clouds. This evidence, derived from PSD measurements, indicates that homogeneous freezing ice nucleation dominates in mid-latitude synoptic cirrus clouds, whereas heterogeneous ice nucleation processes dominate in mid-latitude anvil cirrus. Based on these findings, De was parameterized in terms of temperature (T) for conditions dominated by (1) homo- and (2) heterogeneous ice nucleation. From this, an experiment was designed for global climate models (GCMs). The net radiative forcing from cirrus clouds may be affected by the means ice is produced (homo- or heterogeneously), and this net forcing contributes to climate sensitivity (i.e. the change in mean global surface temperature resulting from a doubling of CO2). The objective of this GCM experiment was to determine how a change in ice nucleation mode affects the predicted global radiation balance. In the first simulation (Run 1), the De-T relationship for homogeneous nucleation is used at all latitudes, while in the second simulation (Run 2), the De-T relationship for heterogeneous nucleation is used at all latitudes. For both runs, Vm is calculated from De. Two GCMs were used; the Community Atmosphere Model version 5 (CAM5) and a European GCM known as ECHAM5 (thanks to our European colleagues who collaborated with us). Similar results were obtained from both GCMs in the Northern Hemisphere mid-latitudes, with a net cooling of ~ 1.0 W m-2 due to heterogeneous nucleation, relative to Run 1. The mean global net cooling was 2.4 W m-2 for the ECHAM5 GCM while CAM5 produced a mean global net cooling of about 0.8 W m-2. This dependence of the radiation balance on nucleation mode is substantial when one considers the direct radiative forcing from a CO2 doubling is 4 W m-2. The differences between GCMs in mean global net cooling estimates may demonstrate a need for improving the representation of cirrus clouds in GCMs, including the coupling between microphysical and radiative properties. Unfortunately, after completing this GCM experiment, we learned from the company that provided the 2D-S microphysical data that the data was corrupted due to a computer program coding problem. Therefore the microphysical data had to be reprocessed and reanalyzed, and the GCM experiments were redone under our current ASR project but using an improved experimental design.

  1. Paleoclimate and Glaciological Reconstruction in Central Asia Through The Collection and Analysis of Ice Cores and Instrumental Data From the Tien Shan

    SciTech Connect (OSTI)

    Cameron P. Wake; Vladimir Aizen; Karl Kreutz

    2001-05-30

    Paleoclimate and Glaciological Reconstruction in Central Asis Through The Collection And Analysis of Ice Cores and Instrumental Data From The Tien Shan

  2. Ice Thermal Storage Systems for LWR Supplemental Cooling and Peak Power Shifting

    SciTech Connect (OSTI)

    Haihua Zhao; Hongbin Zhang; Phil Sharpe; Blaise Hamanaka; Wei Yan; WoonSeong Jeong

    2010-06-01

    Availability of enough cooling water has been one of the major issues for the nuclear power plant site selection. Cooling water issues have frequently disrupted the normal operation at some nuclear power plants during heat waves and long draught. The issues become more severe due to the new round of nuclear power expansion and global warming. During hot summer days, cooling water leaving a power plant may become too hot to threaten aquatic life so that environmental regulations may force the plant to reduce power output or even temporarily to be shutdown. For new nuclear power plants to be built at areas without enough cooling water, dry cooling can be used to remove waste heat directly into the atmosphere. However, dry cooling will result in much lower thermal efficiency when the weather is hot. One potential solution for the above mentioned issues is to use ice thermal storage systems (ITS) that reduce cooling water requirements and boost the plant’s thermal efficiency in hot hours. ITS uses cheap off-peak electricity to make ice and uses those ice for supplemental cooling during peak demand time. ITS is suitable for supplemental cooling storage due to its very high energy storage density. ITS also provides a way to shift large amount of electricity from off peak time to peak time. Some gas turbine plants already use ITS to increase thermal efficiency during peak hours in summer. ITSs have also been widely used for building cooling to save energy cost. Among three cooling methods for LWR applications: once-through, wet cooling tower, and dry cooling tower, once-through cooling plants near a large water body like an ocean or a large lake and wet cooling plants can maintain the designed turbine backpressure (or condensation temperature) during 99% of the time; therefore, adding ITS to those plants will not generate large benefits. For once-through cooling plants near a limited water body like a river or a small lake, adding ITS can bring significant economic benefits and avoid forced derating and shutdown during extremely hot weather. For the new plants using dry cooling towers, adding the ice thermal storage systems can effectively reduce the efficiency loss and water consumption during hot weather so that new LWRs could be considered in regions without enough cooling water. \\ This paper presents the feasibility study of using ice thermal storage systems for LWR supplemental cooling and peak power shifting. LWR cooling issues and ITS application status will be reviewed. Two ITS application case studies will be presented and compared with alternative options: one for once-through cooling without enough cooling for short time, and the other with dry cooling. Because capital cost, especially the ice storage structure/building cost, is the major cost for ITS, two different cost estimation models are developed: one based on scaling method, and the other based on a preliminary design using Building Information Modeling (BIM), an emerging technology in Architecture/Engineering/Construction, which enables design options, performance analysis and cost estimating in the early design stage.

  3. Full-physics 3D heterogeneous simulations of electromagnetic induction fields on level and deformed sea ice

    SciTech Connect (OSTI)

    Samluk, Jesse P.; Geiger, Cathleen A.; Weiss, Chester J.; Kolodzey, James

    2015-10-01

    In this article we explore simulated responses of electromagnetic (EM) signals relative to in situ field surveys and quantify the effects that different values of conductivity in sea ice have on the EM fields. We compute EM responses of ice types with a three-dimensional (3-D) finite-volume discretization of Maxwell's equations and present 2-D sliced visualizations of their associated EM fields at discrete frequencies. Several interesting observations result: First, since the simulator computes the fields everywhere, each gridcell acts as a receiver within the model volume, and captures the complete, coupled interactions between air, snow, sea ice and sea water as a function of their conductivity; second, visualizations demonstrate how 1-D approximations near deformed ice features are violated. But the most important new finding is that changes in conductivity affect EM field response by modifying the magnitude and spatial patterns (i.e. footprint size and shape) of current density and magnetic fields. These effects are demonstrated through a visual feature we define as 'null lines'. Null line shape is affected by changes in conductivity near material boundaries as well as transmitter location. Our results encourage the use of null lines as a planning tool for better ground-truth field measurements near deformed ice types.

  4. Full-physics 3D heterogeneous simulations of electromagnetic induction fields on level and deformed sea ice

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Samluk, Jesse P.; Geiger, Cathleen A.; Weiss, Chester J.; Kolodzey, James

    2015-10-01

    In this article we explore simulated responses of electromagnetic (EM) signals relative to in situ field surveys and quantify the effects that different values of conductivity in sea ice have on the EM fields. We compute EM responses of ice types with a three-dimensional (3-D) finite-volume discretization of Maxwell's equations and present 2-D sliced visualizations of their associated EM fields at discrete frequencies. Several interesting observations result: First, since the simulator computes the fields everywhere, each gridcell acts as a receiver within the model volume, and captures the complete, coupled interactions between air, snow, sea ice and sea water asmore » a function of their conductivity; second, visualizations demonstrate how 1-D approximations near deformed ice features are violated. But the most important new finding is that changes in conductivity affect EM field response by modifying the magnitude and spatial patterns (i.e. footprint size and shape) of current density and magnetic fields. These effects are demonstrated through a visual feature we define as 'null lines'. Null line shape is affected by changes in conductivity near material boundaries as well as transmitter location. Our results encourage the use of null lines as a planning tool for better ground-truth field measurements near deformed ice types.« less

  5. Crystal Field Disorder in the Quantum Spin Ice Ground State of Tb2Sn2 xTixO7

    SciTech Connect (OSTI)

    Gaulin, Bruce D.; Zhang, J.; Dahlberg, M. L.; Matthews, Maria J.; Bert, F.; Kermarrec, E.; Fritsch, Katharina; Granroth, Garrett E; Jiramongkolchai, P.; Amato, A.; Baines, C.; Cava, R. J.; Mendels, P.; Schiffer, P

    2015-01-01

    Spin ice physics marries that of hydrogen disorder in water ice, first discussed almost 60 years ago by Pauling, and that of low temperature magnetism on certain networks of connected tetrahedra. Recently the classical spin ice mag- nets Ho2Ti2O7 and Dy2Ti2O7 have shown an emergent artificial magneto- statics , which manifests itself as Coulombic spin correlations and excitations behaving as diffusive magnetic monopoles. The related pyrochlore magnet, Tb2Ti2O7, has been proposed as a quantum variant of spin ice, stabilized by 1 virtual excitations between the crystal field (CF) ground state doublet appro- priate to Tb3+, and its low lying excited state doublet. Isostructural Tb2Sn2O7 displays soft spin ice order, and its Tb3+ ground and excited CF eigenstates are known to differ relative to those of Tb2Ti2O7. We present a comprehensive study of Tb2Sn2 xTixO7 showing a novel, dynamic spin liquid state for all x other than the end members (0, 2). This state is the result of disorder in the low lying Tb3+ CF environments which de-stabilizes the mechanism by which quantum fluctuations contribute to ground state selection in Tb2Sn2 xTixO7.

  6. Total reflection infrared spectroscopy of water-ice and frozen aqueous NaCl solutions

    SciTech Connect (OSTI)

    Walker, Rachel L.; Searles, Keith; Willard, Jesse A.; Michelsen, Rebecca R. H., E-mail: RMichelsen@rmc.edu [Department of Chemistry, Randolph-Macon College, P.O. Box 5005, Ashland, Virginia 23005 (United States)] [Department of Chemistry, Randolph-Macon College, P.O. Box 5005, Ashland, Virginia 23005 (United States)

    2013-12-28

    Liquid-like and liquid water at and near the surface of water-ice and frozen aqueous sodium chloride films were observed using attenuated total reflection infrared spectroscopy (ATR-IR). The concentration of NaCl ranged from 0.0001 to 0.01 M and the temperature varied from the melting point of water down to 256 K. The amount of liquid brine at the interface of the frozen films with the germanium ATR crystal increased with salt concentration and temperature. Experimental spectra are compared to reflection spectra calculated for a simplified morphology of a uniform liquid layer between the germanium crystal and the frozen film. This morphology allows for the amount of liquid observed in an experimental spectrum to be converted to the thickness of a homogenous layer with an equivalent amount of liquid. These equivalent thickness ranges from a nanometer for water-ice at 260 K to 170 nm for 0.01 M NaCl close to the melting point. The amounts of brine observed are over an order of magnitude less than the total liquid predicted by equilibrium thermodynamic models, implying that the vast majority of the liquid fraction of frozen solutions may be found in internal inclusions, grain boundaries, and the like. Thus, the amount of liquid and the solutes dissolved in them that are available to react with atmospheric gases on the surfaces of snow and ice are not well described by thermodynamic equilibrium models which assume the liquid phase is located entirely at the surface.

  7. On the radiolysis of ethylene ices by energetic electrons and implications to the extraterrestrial hydrocarbon chemistry

    SciTech Connect (OSTI)

    Zhou, Li; Maity, Surajit; Abplanalp, Matt; Turner, Andrew; Kaiser, Ralf I.

    2014-07-20

    The chemical processing of ethylene ices (C{sub 2}H{sub 4}) by energetic electrons was investigated at 11 K to simulate the energy transfer processes and synthesis of new molecules induced by secondary electrons generated in the track of galactic cosmic ray particles. A combination of Fourier transform infrared spectrometry (solid state) and quadrupole mass spectrometry (gas phase) resulted in the identification of six hydrocarbon molecules: methane (CH{sub 4}), the C2 species acetylene (C{sub 2}H{sub 2}), ethane (C{sub 2}H{sub 6}), the ethyl radical (C{sub 2}H{sub 5}), andfor the very first time in ethylene irradiation experimentsthe C4 hydrocarbons 1-butene (C{sub 4}H{sub 8}) and n-butane (C{sub 4}H{sub 10}). By tracing the temporal evolution of the newly formed molecules spectroscopically online and in situ, we were also able to fit the kinetic profiles with a system of coupled differential equations, eventually providing mechanistic information, reaction pathways, and rate constants on the radiolysis of ethylene ices and the inherent formation of smaller (C1) and more complex (C2, C4) hydrocarbons involving carbon-hydrogen bond ruptures, atomic hydrogen addition processes, and radical-radical recombination pathways. We also discuss the implications of these results on the hydrocarbon chemistry on Titan's surface and on ice-coated, methane-bearing interstellar grains as present in cold molecular clouds such as TMC-1.

  8. Distinguishing neutrino mass hierarchies using dark matter annihilation signals at IceCube

    SciTech Connect (OSTI)

    Allahverdi, Rouzbeh; Dutta, Bhaskar; Ghosh, Dilip Kumar; Knockel, Bradley; Saha, Ipsita

    2015-12-01

    We explore the possibility of distinguishing neutrino mass hierarchies through the neutrino signal from dark matter annihilation at neutrino telescopes. We consider a simple extension of the standard model where the neutrino masses and mixing angles are obtained via the type-II seesaw mechanism as an explicit example. We show that future extensions of IceCube neutrino telescope may detect the neutrino signal from DM annihilation at the Galactic Center and inside the Sun, and differentiate between the normal and inverted mass hierarchies, in this model.

  9. Radiation Dry Bias in the TWP-ICE Radiosonde Soundings Solar Zenith Angle Correction Factor

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Radiation Dry Bias in the TWP-ICE Radiosonde Soundings Solar Zenith Angle Correction Factor Figure 3: Ratio of MWR TCWV to radiosonde derived TCWV, and the solar zenith angle at the radiosonde launch time (black dots). The dry bias observed in sonde TCWV values is mainly attributable to a dry RH bias near the surface The red dots show the 1000 hPa RH correction factors suggested by Voemel et al for sondes launched near noon (10-30 degree solar zenith angle), and at night time (90 degree zenith

  10. Sleuthing the Fate of Water in Ancient Aquifers and Ice Cores | U.S. DOE

    Office of Science (SC) Website

    Office of Science (SC) Sleuthing the Fate of Water in Ancient Aquifers and Ice Cores Nuclear Physics (NP) NP Home About Research Facilities Science Highlights Benefits of NP Funding Opportunities Nuclear Science Advisory Committee (NSAC) Community Resources Contact Information Nuclear Physics U.S. Department of Energy SC-26/Germantown Building 1000 Independence Ave., SW Washington, DC 20585 P: (301) 903-3613 F: (301) 903-3833 E: Email Us More Information » 10.01.12 Sleuthing the Fate of

  11. Glaciers, ice sheets, and sea level: effect of a CO/sub 2/-induced climatic change

    SciTech Connect (OSTI)

    1985-09-01

    The workshop examined the basic questions of how much water has been exchanged between land ice and ocean during the last century, what is happening now, and, given existing climate-modeling prediction, how much exchange can be expected in the next century. In addition, the evidence for exchange was examined and gaps in that evidence were identified. The report includes the 23 presentations made at the workshop, summarizes the workshop discussion, and presents the Committee's findings and recommendations. Separate abstracts have been prepared for the 23 presentations.

  12. A Comprehensive Parameterization of Heterogeneous Ice Nucleation of Dust Surrogate: Laboratory Study with Hematite Particles and Its Application to Atmospheric Models

    SciTech Connect (OSTI)

    Hiranuma, Naruki; Paukert, Marco; Steinke, Isabelle; Zhang, Kai; Kulkarni, Gourihar R.; Hoose, Corinna; Schnaiter, Martin; Saathoff, Harald; Mohler, Ottmar

    2014-12-10

    A new heterogeneous ice nucleation parameterization that covers a wide temperature range (-36 ?C to -78 ?C) is presented. Developing and testing such an ice nucleation parameterization, which is constrained through identical experimental conditions, is critical in order to accurately simulate the ice nucleation processes in cirrus clouds. The surface-scaled ice nucleation efficiencies of hematite particles, inferred by ns, were derived from AIDA (Aerosol Interaction and Dynamics in the Atmosphere) cloud chamber measurements under water subsaturated conditions that were realized by continuously changing temperature (T) and relative humidity with respect to ice (RHice) in the chamber. Our measurements showed several different pathways to nucleate ice depending on T and RHice conditions. For instance, almost independent freezing was observed at -60 ?C < T < -50 ?C, where RHice explicitly controlled ice nucleation efficiency, while both T and RHice played roles in other two T regimes: -78 ?C < T < -60 ?C and -50 ?C < T < -36 ?C. More specifically, observations at T colder than -60 ?C revealed that higher RHice was necessary to maintain constant ns, whereas T may have played a significant role in ice nucleation at T warmer than -50 ?C. We implemented new ns parameterizations into two cloud models to investigate its sensitivity and compare with the existing ice nucleation schemes towards simulating cirrus cloud properties. Our results show that the new AIDA-based parameterizations lead to an order of magnitude higher ice crystal concentrations and inhibition of homogeneous nucleation in colder temperature regions. Our cloud simulation results suggest that atmospheric dust particles that form ice nuclei at lower temperatures, below -36 ?C, can potentially have stronger influence on cloud properties such as cloud longevity and initiation when compared to previous parameterizations.

  13. Galactic chemical evolution and solar s-process abundances: Dependence on the {sup 13}C-pocket structure

    SciTech Connect (OSTI)

    Bisterzo, S.; Travaglio, C.; Gallino, R.; Wiescher, M.; Kppeler, F. E-mail: sarabisterzo@gmail.com

    2014-05-20

    We study the s-process abundances (A ? 90) at the epoch of the solar system formation. Asymptotic giant branch yields are computed with an updated neutron capture network and updated initial solar abundances. We confirm our previous results obtained with a Galactic chemical evolution (GCE) model: (1) as suggested by the s-process spread observed in disk stars and in presolar meteoritic SiC grains, a weighted average of s-process strengths is needed to reproduce the solar s distribution of isotopes with A > 130; and (2) an additional contribution (of about 25%) is required in order to represent the solar s-process abundances of isotopes from A = 90 to 130. Furthermore, we investigate the effect of different internal structures of the {sup 13}C pocket, which may affect the efficiency of the {sup 13}C(?, n){sup 16}O reaction, the major neutron source of the s process. First, keeping the same {sup 13}C profile adopted so far, we modify by a factor of two the mass involved in the pocket; second, we assume a flat {sup 13}C profile in the pocket, and we test again the effects of the variation of the mass of the pocket. We find that GCE s predictions at the epoch of the solar system formation marginally depend on the size and shape of the {sup 13}C pocket once a different weighted range of {sup 13}C-pocket strengths is assumed. We obtain that, independently of the internal structure of the {sup 13}C pocket, the missing solar system s-process contribution in the range from A = 90 to 130 remains essentially the same.

  14. Spreading of crude petroleum in brash ice; Effects of oil`s physical properties and water current

    SciTech Connect (OSTI)

    Sayed, M.; Kotlyar, L.S.; Sparks, B.D.

    1994-12-31

    Experiments were conducted in a refrigerated, circulating current flume to examine crude oil spreading in brash ice. Amauligak, Hibernia and Norman Wells crudes were tested. Measurements of the physical properties of the oils were also conducted, including: surface and interfacial tensions as well as viscosities. Spreading coefficients were calculated from measured surface and interfacial tensions. Results were obtained for original and weathered oils. For the spreading tests, spill volumes up to 3 liters and water currents up to 0.55 m/s were used. Tests were done using both fresh water ice and saline ice. Slick dimensions were measured, and modes of oil spreading were observed. Slick dimensions depended on oil type, but were not influenced by water current. Oils of high spreading coefficient and low viscosity spread over larger areas than those with low spreading coefficient and high viscosity.

  15. Development of a Laser-Produced Plasma X-ray source for Phase-Contrast Radiography of DT Ice layers

    SciTech Connect (OSTI)

    Izumi, N; Dewald, E; Kozioziemski, B; Landen, O L; Koch, J A

    2008-07-21

    Refraction enhanced x-ray phase contrast imaging is crucial for characterization of deuterium-tritium (DT) ice layer roughness in optically opaque inertial confinement fusion capsules. To observe the time development of DT ice roughness over {approx} second timescales, we need a bright x-ray source that can produce an image faster than the evolution of the ice surface roughness. A laser produced plasma x-ray source is one of the candidates that can meet this requirement. We performed experiments at the Janus laser facility at Lawrence Livermore National Laboratory and assessed the characteristics of the laser produced plasma x-ray source as a potential backlight for in situ target characterization.

  16. Ground state study of the thin ferromagnetic nano-islands for artificial spin ice arrays

    SciTech Connect (OSTI)

    Vieira Jnior, D. S.; Leonel, S. A. Dias, R. A. Toscano, D. Coura, P. Z. Sato, F.

    2014-09-07

    In this work, we used numerical simulations to study the magnetic ground state of the thin elongated (elliptical) ferromagnetic nano-islands made of Permalloy. In these systems, the effects of demagnetization of dipolar source generate a strong magnetic anisotropy due to particle shape, defining two fundamental magnetic ground state configurationsvortex or type C. To describe the system, we considered a model Hamiltonian in which the magnetic moments interact through exchange and dipolar potentials. We studied the competition between the vortex states and aligned statestype Cas a function of the shape of each elliptical nano-islands and constructed a phase diagram vortextype C state. Our results show that it is possible to obtain the elongated nano-islands in the C-state with aspect ratios less than 2, which is interesting from the technological point of view because it will be possible to use smaller islands in spin ice arrays. Generally, the experimental spin ice arrangements are made with quite elongated particles with aspect ratio approximately 3 to ensure the C-state.

  17. Morphology Of Diesel Soot Residuals From Supercooled Water Droplets And Ice Crystals: Implications For Optical Properties

    SciTech Connect (OSTI)

    China, Swarup; Kulkarni, Gourihar; Scarnatio, Barbara; Sharma, Noopur; Pekour, Mikhail S.; Shilling, John E.; Wilson, Jacqueline M.; Zelenyuk, Alla; Chand, Duli; Liu, Shang; Aiken, Allison; Dubey, Manvendra K.; Laskin, Alexander; Zaveri, Rahul A.; Mazzoleni, Claudio

    2015-11-04

    Freshly emitted soot particles are fractal-like aggregates, but atmospheric processing often transforms their morphology. Morphology of soot particles plays an important role in determining their optical properties, life cycle and hence their effect on Earths radiative balance. However, little is known about the morphology of soot particles that participated in cold cloud processes. Here we report results from laboratory experiments that simulate cold cloud processing of diesel soot particles by allowing them to form supercooled droplets and ice crystals at -20 and -40C, respectively. Electron microscopy revealed that soot residuals from ice crystals were more compact (roundness~0.55) than those from supercooled droplets (roundness ~0.45), while nascent soot particles were the least compact (roundness~0.41). Optical simulations using the discrete dipole approximation showed that the more compact structure enhances soot single scattering albedo by a factor up to 1.4, thereby reducing the top-of-the-atmosphere direct radiative forcing by ~63%. These results underscore that climate models should consider the morphological evolution of soot particles due to cold cloud processing to improve the estimate of direct radiative forcing of soot.

  18. Adsorption of 2-propanol on ice probed by ambient pressure X-ray photoelectron spectroscopy

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Newberg, John T.; Bluhm, Hendrik

    2015-08-18

    The interaction of 2-propanol with ice was examined via ambient pressure X-ray photoelectron spectroscopy (APXPS), a surface sensitive technique that probes the adsorbed 2-propanol directly with submonolayer resolution. Isothermal uptake experiments were performed on vapor deposited ice at 227 K in the presence of the equilibrium water vapor pressure of 0.05 Torr and 2-propanol partial pressures ranging from 5 × 10-5 to 2 × 10-3 Torr. The C 1s APXPS spectra of adsorbed 2-propanol showed two characteristic peaks associated with the COH alcohol group and CMe methyl groups in a 1 : 2 ratio, respectively. Coverage increased with 2-propanol partialmore » pressure and followed first order Langmuir kinetics with a Langmuir constant of K = 6.3 × 103 Torr-1. The 1 : 2 ratio of COH : CMe remained constant with increasing coverage, indicating there is no chemical reaction upon adsorption. The observed Langmuir kinetics using APXPS is consistent with previous observations of other small chain alcohols via indirect adsorption methods using, e.g., Knudsen cell and coated wall flow tube reactors.« less

  19. Adsorption of 2-propanol on ice probed by ambient pressure X-ray photoelectron spectroscopy

    SciTech Connect (OSTI)

    Newberg, John T.; Bluhm, Hendrik

    2015-08-18

    The interaction of 2-propanol with ice was examined via ambient pressure X-ray photoelectron spectroscopy (APXPS), a surface sensitive technique that probes the adsorbed 2-propanol directly with submonolayer resolution. Isothermal uptake experiments were performed on vapor deposited ice at 227 K in the presence of the equilibrium water vapor pressure of 0.05 Torr and 2-propanol partial pressures ranging from 5 10-5 to 2 10-3 Torr. The C 1s APXPS spectra of adsorbed 2-propanol showed two characteristic peaks associated with the COH alcohol group and CMe methyl groups in a 1 : 2 ratio, respectively. Coverage increased with 2-propanol partial pressure and followed first order Langmuir kinetics with a Langmuir constant of K = 6.3 103 Torr-1. The 1 : 2 ratio of COH : CMe remained constant with increasing coverage, indicating there is no chemical reaction upon adsorption. The observed Langmuir kinetics using APXPS is consistent with previous observations of other small chain alcohols via indirect adsorption methods using, e.g., Knudsen cell and coated wall flow tube reactors.

  20. Measurement of sound speed vs. depth in South Pole ice: pressure waves and shear waves

    SciTech Connect (OSTI)

    IceCube Collaboration; Klein, Spencer

    2009-06-04

    We have measured the speed of both pressure waves and shear waves as a function of depth between 80 and 500 m depth in South Pole ice with better than 1% precision. The measurements were made using the South Pole Acoustic Test Setup (SPATS), an array of transmitters and sensors deployed in the ice at the South Pole in order to measure the acoustic properties relevant to acoustic detection of astrophysical neutrinos. The transmitters and sensors use piezoceramics operating at {approx}5-25 kHz. Between 200 m and 500 m depth, the measured profile is consistent with zero variation of the sound speed with depth, resulting in zero refraction, for both pressure and shear waves. We also performed a complementary study featuring an explosive signal propagating vertically from 50 to 2250 m depth, from which we determined a value for the pressure wave speed consistent with that determined for shallower depths, higher frequencies, and horizontal propagation with the SPATS sensors. The sound speed profile presented here can be used to achieve good acoustic source position and emission time reconstruction in general, and neutrino direction and energy reconstruction in particular. The reconstructed quantities could also help separate neutrino signals from background.

  1. Higher order dark matter annihilations in the Sun and implications for IceCube

    SciTech Connect (OSTI)

    Ibarra, Alejandro; Totzauer, Maximilian; Wild, Sebastian E-mail: maximilian.totzauer@mytum.de

    2014-04-01

    Dark matter particles captured in the Sun would annihilate producing a neutrino flux that could be detected at the Earth. In some channels, however, the neutrino flux lies in the MeV range and is thus undetectable at IceCube, namely when the dark matter particles annihilate into e{sup +}e{sup ?}, ?{sup +}?{sup ?} or light quarks. On the other hand, the same interaction that mediates the annihilations into light fermions also leads, via higher order effects, to the production of weak gauge bosons (and in the case of quarks also gluons) that generate a high energy neutrino flux potentially observable at IceCube. We consider in this paper tree level annihilations into a fermion-antifermion pair with the associated emission of one gauge boson and one loop annihilations into two gauge bosons, and we calculate the limits on the scattering cross section of dark matter particles with protons in scenarios where the dark matter particle couples to electrons, muons or light quarks from the non-observation of an excess of neutrino events in the direction of the Sun. We find that the limits on the spin-dependent scattering cross section are, for some scenarios, stronger than the limits from direct detection experiments.

  2. On the detection of crevasses in glacial ice with synthetic-aperture radar.

    SciTech Connect (OSTI)

    Brock, Billy C.

    2010-02-01

    The intent of this study is to provide an analysis of the scattering from a crevasse in Antarctic ice, utilizing a physics-based model for the scattering process. Of primary interest is a crevasse covered with a snow bridge, which makes the crevasse undetectable in visible-light images. It is demonstrated that a crevasse covered with a snow bridge can be visible in synthetic-aperture-radar (SAR) images. The model of the crevasse and snow bridge incorporates a complex dielectric permittivity model for dry snow and ice that takes into account the density profile of the glacier. The surface structure is based on a fractal model that can produce sastrugi-like features found on the surface of Antarctic glaciers. Simulated phase histories, computed with the Shooting and Bouncing Ray (SBR) method, are processed into SAR images. The viability of the SBR method for predicting scattering from a crevasse covered with a snow bridge is demonstrated. Some suggestions for improving the model are given.

  3. Light-absorbing Particles in Snow and Ice: Measurement and Modeling of Climatic and Hydrological Impact

    SciTech Connect (OSTI)

    Qian, Yun; Yasunari, Teppei J.; Doherty, Sarah J.; Flanner, M. G.; Lau, William K.; Ming, J.; Wang, Hailong; Wang, Mo; Warren, Stephen G.; Zhang, Rudong

    2015-01-01

    Light absorbing particles (LAP, e.g., black carbon, brown carbon, and dust) influence water and energy budgets of the atmosphere and snowpack in multiple ways. In addition to their effects associated with atmospheric heating by absorption of solar radiation and interactions with clouds, LAP in snow on land and ice can reduce the surface reflectance (a.k.a., surface darkening), which is likely to accelerate the snow aging process and further reduces snow albedo and increases the speed of snowpack melt. LAP in snow and ice (LAPSI) has been identified as one of major forcings affecting climate change, e.g. in the fourth and fifth assessment reports of IPCC. However, the uncertainty level in quantifying this effect remains very high. In this review paper, we document various technical methods of measuring LAPSI and review the progress made in measuring the LAPSI in Arctic, Tibetan Plateau and other mid-latitude regions. We also report the progress in modeling the mass concentrations, albedo reduction, radiative forcing, andclimatic and hydrological impact of LAPSI at global and regional scales. Finally we identify some research needs for reducing the uncertainties in the impact of LAPSI on global and regional climate and the hydrological cycle.

  4. IMPROVED MOCK GALAXY CATALOGS FOR THE DEEP2 GALAXY REDSHIFT SURVEY FROM SUBHALO ABUNDANCE AND ENVIRONMENT MATCHING

    SciTech Connect (OSTI)

    Gerke, Brian F.; Wechsler, Risa H.; Behroozi, Peter S.; Yan, Renbin; Coil, Alison L.

    2013-09-15

    We develop empirical methods for modeling the galaxy population and populating cosmological N-body simulations with mock galaxies according to the observed properties of galaxies in survey data. We use these techniques to produce a new set of mock catalogs for the DEEP2 Galaxy Redshift Survey based on the output of the high-resolution Bolshoi simulation, as well as two other simulations with different cosmological parameters, all of which we release for public use. The mock-catalog creation technique uses subhalo abundance matching to assign galaxy luminosities to simulated dark-matter halos. It then adds color information to the resulting mock galaxies in a manner that depends on the local galaxy density, in order to reproduce the measured color-environment relation in the data. In the course of constructing the catalogs, we test various models for including scatter in the relation between halo mass and galaxy luminosity, within the abundance-matching framework. We find that there is no constant-scatter model that can simultaneously reproduce both the luminosity function and the autocorrelation function of DEEP2. This result has implications for galaxy-formation theory, and it restricts the range of contexts in which the mock catalogs can be usefully applied. Nevertheless, careful comparisons show that our new mock catalogs accurately reproduce a wide range of the other properties of the DEEP2 catalog, suggesting that they can be used to gain a detailed understanding of various selection effects in DEEP2.

  5. LABORATORY STUDIES ON THE IRRADIATION OF SOLID ETHANE ANALOG ICES AND IMPLICATIONS TO TITAN'S CHEMISTRY

    SciTech Connect (OSTI)

    Kim, Y. S.; Bennett, C. J.; Chen, L-H; Kaiser, R. I.; O'Brien, K.

    2010-03-10

    Pure ethane ices (C{sub 2}H{sub 6}) were irradiated at 10, 30, and 50 K under contamination-free, ultrahigh vacuum conditions with energetic electrons generated in the track of galactic cosmic-ray (GCR) particles to simulate the interaction of GCRs with ethane ices in the outer solar system. The chemical processing of the samples was monitored by a Fourier transform infrared spectrometer and a quadrupole mass spectrometer during the irradiation phase and subsequent warm-up phases on line and in situ in order to extract qualitative (products) and quantitative (rate constants and yields) information on the newly synthesized molecules. Six hydrocarbons, methane (CH{sub 4}), acetylene (C{sub 2}H{sub 2}), ethylene (C{sub 2}H{sub 4}), and the ethyl radical (C{sub 2}H{sub 5}), together with n-butane (C{sub 4}H{sub 10}) and butene (C{sub 4}H{sub 8}), were found to form at the radiation dose reaching 1.4 eV per molecule. The column densities of these species were quantified in the irradiated ices at each temperature, permitting us to elucidate the temperature and phase-dependent production rates of individual molecules. A kinetic reaction scheme was developed to fit column densities of those species produced during irradiation of amorphous/crystalline ethane held at 10, 30, or 50 K. In general, the yield of the newly formed molecules dropped consistently for all species as the temperature was raised from 10 K to 50 K. Second, the yield in the amorphous samples was found to be systematically higher than in the crystalline samples at constant temperature. A closer look at the branching ratios indicates that ethane decomposes predominantly to ethylene and molecular hydrogen, which may compete with the formation of n-butane inside the ethane matrix. Among the higher molecular products, n-butane dominates. Of particular relevance to the atmosphere of Saturn's moon Titan is the radiation-induced methane production from ethane-an alternative source of replenishing methane into the atmosphere. Finally, we discuss to what extent the n-butane could be the source of ''higher organics'' on Titan's surface thus resembling a crucial sink of condensed ethane molecules.

  6. Invited Article: SUBGLACIOR: An optical analyzer embedded in an Antarctic ice probe for exploring the past climate

    SciTech Connect (OSTI)

    Grilli, R.; Marrocco, N.; Desbois, T.; Guillerm, C.; Triest, J.; Kerstel, E.; Romanini, D.

    2014-11-15

    This article describes the advances made in the development of a specific optical spectrometer based on the Optical Feedback-Cavity Enhanced Absorption Spectroscopy technique for exploring past climate by probing the original composition of the atmosphere stored in the ice sheet of a glacier. Based on significant technological progresses and unconventional approaches, SUBGLACIOR will be a revolutionary tool for ice-core research: the optical spectrometer, directly embedded in the drilling probe, will provide in situ real-time measurements of deuterium isotopic variations (?{sup 2}H ) and CH{sub 4} concentrations down to 3500 m of ice depth within a single Antarctic season. The instrument will provide simultaneous and real-time vertical profiles of these two key climate signatures in order to evaluate if a target site can offer ice cores as old as 1.5 million years by providing direct insight into past temperatures and climate cycles. The spectrometer has a noise equivalent absorption coefficient of 2.8 10{sup ?10} cm{sup ?1} Hz{sup ?1/2}, corresponding to a detection limit of 0.2 ppbv for CH{sub 4} and a precision of 0.2 on the ?{sup 2}H of H{sub 2}O within 1 min acquisition time.

  7. Integrating laboratory and field data to quantify the immersion freezing ice nucleation activity of mineral dust particles

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    DeMott, P. J.; Prenni, A. J.; McMeeking, G. R.; Sullivan, R. C.; Petters, M. D.; Tobo, Y.; Niemand, M.; Möhler, O.; Snider, J. R.; Wang, Z.; et al

    2014-06-27

    Data from both laboratory studies and atmospheric measurements are used to develop a simple parametric description for the immersion freezing activity of natural mineral dust particles. Measurements made with the Colorado State University (CSU) continuous flow diffusion chamber (CFDC) when processing mineral dust aerosols at a nominal 105% relative humidity with respect to water (RHw) are taken to approximate the immersion freezing nucleation activity of particles. Ice active frozen fractions vs. temperature for dusts representative of Saharan and Asian desert sources were consistent with similar measurements in atmospheric dust plumes for a limited set of comparisons available. The parameterization developedmore » follows the form of one suggested previously for atmospheric particles of non-specific composition in quantifying ice nucleating particle concentrations as functions of temperature and the total number concentration of particles larger than 0.5 μm diameter. Such an approach does not explicitly account for surface area and time dependencies for ice nucleation, but sufficiently encapsulates the activation properties for potential use in regional and global modeling simulations, and possible application in developing remote sensing retrievals for ice nucleating particles. A correction factor is introduced to account for the apparent underestimate (by approximately 3, on average) of the immersion freezing fraction of mineral dust particles for CSU CFDC data processed at an RHw of 105% vs. maximum fractions active at higher RHw. Instrumental factors that affect activation behavior vs. RHw in CFDC instruments remain to be fully explored in future studies. Nevertheless, the use of this correction factor is supported by comparison to ice activation data obtained for the same aerosols from Aerosol Interactions and Dynamics of the Atmosphere (AIDA) expansion chamber cloud parcel experiments. Further comparison of the new parameterization to the immersion freezing surface active site density parameterization for mineral dust particles, developed separately from AIDA experimental data alone, shows excellent agreement for data collected in a descent through a Saharan aerosol layer. These studies support the utility of laboratory measurements to obtain atmospherically-relevant data on the ice nucleation properties of dust and other particle types, and suggest the suitability of considering all mineral dust as a single type of ice nucleating particle as a useful first order approximation in numerical modeling investigations.« less

  8. Integrating laboratory and field data to quantify the immersion freezing ice nucleation activity of mineral dust particles

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    DeMott, P. J.; Prenni, A. J.; McMeeking, G. R.; Sullivan, R. C.; Petters, M. D.; Tobo, Y.; Niemand, M.; Möhler, O.; Snider, J. R.; Wang, Z.; et al

    2015-01-13

    Data from both laboratory studies and atmospheric measurements are used to develop an empirical parameterization for the immersion freezing activity of natural mineral dust particles. Measurements made with the Colorado State University (CSU) continuous flow diffusion chamber (CFDC) when processing mineral dust aerosols at a nominal 105% relative humidity with respect to water (RHw) are taken as a measure of the immersion freezing nucleation activity of particles. Ice active frozen fractions vs. temperature for dusts representative of Saharan and Asian desert sources were consistent with similar measurements in atmospheric dust plumes for a limited set of comparisons available. The parameterizationmore » developed follows the form of one suggested previously for atmospheric particles of non-specific composition in quantifying ice nucleating particle concentrations as functions of temperature and the total number concentration of particles larger than 0.5 μm diameter. Such an approach does not explicitly account for surface area and time dependencies for ice nucleation, but sufficiently encapsulates the activation properties for potential use in regional and global modeling simulations, and possible application in developing remote sensing retrievals for ice nucleating particles. A calibration factor is introduced to account for the apparent underestimate (by approximately 3, on average) of the immersion freezing fraction of mineral dust particles for CSU CFDC data processed at an RHw of 105% vs. maximum fractions active at higher RHw. Instrumental factors that affect activation behavior vs. RHw in CFDC instruments remain to be fully explored in future studies. Nevertheless, the use of this calibration factor is supported by comparison to ice activation data obtained for the same aerosols from Aerosol Interactions and Dynamics of the Atmosphere (AIDA) expansion chamber cloud parcel experiments. Further comparison of the new parameterization, including calibration correction, to predictions of the immersion freezing surface active site density parameterization for mineral dust particles, developed separately from AIDA experimental data alone, shows excellent agreement for data collected in a descent through a Saharan aerosol layer. These studies support the utility of laboratory measurements to obtain atmospherically relevant data on the ice nucleation properties of dust and other particle types, and suggest the suitability of considering all mineral dust as a single type of ice nucleating particle as a useful first-order approximation in numerical modeling investigations.« less

  9. CLUES ON THE REJUVENATION OF THE S0 GALAXY NGC 404 FROM THE CHEMICAL ABUNDANCE OF ITS OUTER DISK

    SciTech Connect (OSTI)

    Bresolin, Fabio

    2013-08-01

    The oxygen abundance of the outer disk of the nearby S0 galaxy NGC 404, a prototypical early-type galaxy with extended star formation, has been derived from the analysis of H II region spectra. The high mean value found, 12 + log(O/H) = 8.6 {+-} 0.1, equivalent to approximately 80% of the solar value, argues against both the previously proposed cold accretion and recent merger scenarios as viable mechanisms for the assembly of the star-forming gas. The combination of the present-day gas metallicity with the published star formation history of this galaxy favors a model in which the recent star forming activity represents the declining tail of the original one.

  10. THE DUSTY NOVA V1065 CENTAURI (NOVA CEN 2007): A SPECTROSCOPIC ANALYSIS OF ABUNDANCES AND DUST PROPERTIES

    SciTech Connect (OSTI)

    Helton, L. Andrew; Woodward, Charles E.; Gehrz, Robert D.; Walter, Frederick M.; Vanlandingham, Karen; Schwarz, Greg J.; Evans, Aneurin; Ness, Jan-Uwe; Geballe, Thomas R.; Greenhouse, Matthew; Krautter, Joachim; Liller, William; Lynch, David K.; Rudy, Richard J.; Shore, Steven N.; Starrfield, Sumner; Truran, Jim

    2010-11-15

    We examine the ejecta evolution of the classical nova V1065 Centauri, constructing a detailed picture of the system based on spectrophotometric observations obtained from 9 to approximately 900 days post-outburst with extensive coverage from optical to mid-infrared wavelengths. We estimate a reddening toward the system of E(B-V) = 0.5 {+-} 0.1, based upon the B - V color and analysis of the Balmer decrement, and derive a distance estimate of 8.7{sup +2.8}{sub -2.1} kpc. The optical spectral evolution is classified as P {sup o}{sub fe} N{sub ne} A{sub o} according to the CTIO Nova Classification system of Williams et al. Photoionization modeling yields absolute abundance values by number, relative to solar of He/H = 1.6 {+-} 0.3, N/H = 144 {+-} 34, O/H = 58 {+-} 18, and Ne/H = 316 {+-} 58 for the ejecta. We derive an ejected gas mass of M{sub g} = (1.6 {+-} 0.2) x 10{sup -4} M{sub sun}. The infrared excess at late epochs in the evolution of the nova arises from dust condensed in the ejecta composed primarily of silicate grains. We estimate a total dust mass, M{sub d} , of order (0.2-3.7) x 10{sup -7} M{sub sun}, inferred from modeling the spectral energy distribution observed with the Spitzer IRS and Gemini-South GNIRS spectrometers. Based on the speed class, neon abundance, and the predominance of silicate dust, we classify V1065 Cen as an ONe-type classical nova.

  11. Are IceCube neutrinos unveiling PeV-scale decaying dark matter?

    SciTech Connect (OSTI)

    Esmaili, Arman; Serpico, Pasquale Dario E-mail: serpico@lapth.cnrs.fr

    2013-11-01

    Recent observations by IceCube, notably two PeV cascades accompanied by events at energies ? (30400) TeV, are clearly in excess over atmospheric background fluxes and beg for an astroparticle physics explanation. Although some models of astrophysical accelerators can account for the observations within current statistics, intriguing features in the energy and possibly angular distributions of the events make worth exploring alternatives. Here, we entertain the possibility of interpreting the data with a few PeV mass scale decaying dark matter, with lifetime of the order of 10{sup 27}s. We discuss generic signatures of this scenario, including its unique energy spectrum distortion with respect to the benchmark E{sub ?}{sup ?2} expectation for astrophysical sources, as well as peculiar anisotropies. A direct comparison with the data show a good match with the above-mentioned features. We further discuss possible future checks of this scenario.

  12. Assessment of ISLOCA risk: Methodology and application to a Westinghouse four-loop ice condenser plant

    SciTech Connect (OSTI)

    Kelly, D.L.; Auflick, J.L.; Haney, L.N.

    1992-04-01

    Inter-system loss-of-coolant accidents (ISLOCAs) have been identified as important contributors to offsite risk for some nuclear power plants. A methodology has been developed for identifying and evaluating plant-specific hardware designs, human factors issues, and accident consequence factors relevant to the estimation of ISLOCA core damage frequency and risk. This report presents a detailed description of the application of this analysis methodology to a Westinghouse four-loop ice condenser plant. This document also includes appendices A through I which provide: System descriptions; ISLOCA event trees; human reliability analysis; thermal hydraulic analysis; core uncovery timing calculations; calculation of system rupture probability; ISLOCA consequences analysis; uncertainty analysis; and component failure analysis.

  13. Spin ice: magnetic excitations without monopole signatures using muon spin rotation

    SciTech Connect (OSTI)

    Dunsiger, Sarah [Technical University, Munich, Germany; Aczel, Adam A. [McMaster University; Arguello, Carlos [Columbia University; Dabkowska, H. A. [McMaster University; Dabkowski, A [McMaster University; Du, Mao-Hua [ORNL; Goko, Tatsuo [Columbia University; Javanparast, B [University of Waterloo, Canada; Lin, T [University of Waterloo, Canada; Ning, F. L. [McMaster University; Noad, H. M. [McMaster University; Singh, David J [ORNL; Williams, T.J. [McMaster University; Uemura, Yasutomo J. [Columbia University; Gingras, M.P.J. [University of Waterloo, Canada; Luke, Graeme M. [McMaster University

    2011-01-01

    Theory predicts the low temperature magnetic excitations in spin ices consist of deconfined magnetic charges, or monopoles. A recent transverse-field (TF) muon spin rotation ({mu}SR) experiment [S.T. Bramwell et al., Nature (London) 461 956 (2009)] reports results claiming to be consistent with the temperature and magnetic field dependence anticipated for monopole nucleation - the so-called second Wien effect. We demonstrate via a new series of {mu}SR experiments in Dy{sub 2}Ti{sub 2}O{sub 7} that such an effect is not observable in a TF {mu}SR experiment. Rather, as found in many highly frustrated magnetic materials, we observe spin fluctuations which become temperature independent at low temperatures, behavior which dominates over any possible signature of thermally nucleated monopole excitations.

  14. Short time proton dynamics in bulk ice and in porous anode solid oxide fuel cell materials

    SciTech Connect (OSTI)

    Basoli, Francesco; Senesi, Roberto; Kolesnikov, Alexander I; Licoccia, Silvia

    2014-01-01

    Oxygen reduction and incorporation into solid electrolytes and the reverse reaction of oxygen evolution play a cru-cial role in Solid Oxide Fuel Cell (SOFC) applications. However a detailed un derstanding of the kinetics of the cor-responding reactions, i.e. on reaction mechanisms, rate limiting steps, reaction paths, electrocatalytic role of materials, is still missing. These include a thorough characterization of the binding potentials experienced by protons in the lattice. We report results of Inelastic Neutron Scattering (INS) measurements of the vibrational state of the protons in Ni- YSZ highly porous composites (75% to 90% ), a ceramic-metal material showing a high electrical conductivity and ther mal stability, which is known to be most effectively used as anodes for solid ox ide fuel cells. The results are compared with INS and Deep Inelastic Neutron Scattering (DINS) experiments on the proton binding states in bulk ice.

  15. The Great 2008 Chinese ice storm, its socioeconomic-ecological impact, and sustainability lessons learned

    SciTech Connect (OSTI)

    Zhou, Dr. Benzhi; Gu, Lianhong; Ding, Yihui; Wu, Zhongmin; Shao, Lan; An, Yanfei; Cao, Yonghui; Duan, Aiguo; Kong, Weijian; Li, Changzhu; Li, Zhengcai; Sun, Honggang; Wang, Shengkun; Wang, Xiaoming; Wang, Xu; Yang, Xiaosheng; Yu, Mukui; Zeng, Bingshan

    2011-01-01

    . Extreme events often expose vulnerabilities of socioeconomic infrastructures and point to directions of much-needed policy change. Integrated impact assessment of such events can lead to finding of sustainability principles. Southern and central China has for decades been undergoing a breakneck pace of socioeconomic development. In early 2008, a massive ice storm struck this region, immobilizing millions of people. The storm was a consequence of sustained convergence between tropical maritime and continental polar air masses, caused by an anomalously stable atmospheric general circulation pattern in both low and high latitudes. Successive waves of freezing rain occurred during a month period, coating southern and central China with a layer of ice 50 to 160mm in thickness. We conducted an integrated impact assessment of this event to determine whether and how the context of socioeconomic and human-disturbed natural systems may affect the transition of natural events into human disasters. We found: 1) without contingency plans, advanced technologies dependent on interrelated energy supplies can create worse problems during extreme events, 2) the weakest link in disaster response lies between science and decision making, 3) biodiversity is a form of long-term insurance for sustainable forestry against extreme events, 4) sustainable extraction of non-timber goods and services is essential to risk planning for extreme events in forest resources use, 5) extreme events can cause food shortage directly by destroying crops and indirectly by disrupting food distribution channels, 6) concentrated economic development increases societal vulnerability to extreme events, and 7) formalized institutional mechanisms are needed to ensure that unexpected opportunities to learn lessons from weather disasters are not lost in distracting circumstances.

  16. Neutrino Data from IceCube and its Predecessor at the South Pole, the Antarctic Muon and Neutrino Detector Array (AMANDA)

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Abbasi, R.

    IceCube is a neutrino observatory for astrophysics with parts buried below the surface of the ice at the South Pole and an air-shower detector array exposed above. The international group of sponsors, led by the National Science Foundation (NSF), that designed and implemented the experiment intends for IceCube to operate and provide data for 20 years. IceCube records the interactions produced by astrophysical neutrinos with energies above 100 GeV, observing the Cherenkov radiation from charged particles produced in neutrino interactions. Its goal is to discover the sources of high-energy cosmic rays. These sources may be active galactic nuclei (AGNs) or massive, collapsed stars where black holes have formed.[Taken from http://www.icecube.wisc.edu/] The data from IceCube's predecessor experiment and detector, AMANDA, IceCubes predecessor detector and experiment is also available at this website. AMANDA pioneered neutrino detection in ice. Over a period of years in the 1990s, detecting strings were buried and activated and by 2000, AMANDA was successfully recording an average of 1,000 neutrino events per year. This site also makes available many images and video from the two experiments.

  17. Chemical Characterization of Individual Particles and Residuals of Cloud Droplets and Ice Crystals Collected On Board Research Aircraft in the ISDAC 2008 Study

    SciTech Connect (OSTI)

    Hiranuma, Naruki; Brooks, Sarah D.; Moffet, Ryan C.; Glen, Andrew; Laskin, Alexander; Gilles, Marry K.; Liu, Peter; MacDonald, A. M.; Strapp, J. Walter; McFarquhar, Greg

    2013-06-24

    Although it has been shown that size of atmospheric particles has a direct correlation with their ability to act as cloud droplet and ice nuclei, the influence of composition of freshly emitted and aged particles in nucleation processes is poorly understood. In this work we combine data from field measurements of ice nucleation with chemical imaging of the sampled particles to link aerosol composition with ice nucleation ability. Field measurements and sampling were conducted during the Indirect and Semidirect Aerosols Campaign (ISDAC) over Barrow, Alaska, in the springtime of 2008. In-situ ice nucleation measurements were conducted using a Continuous Flow Diffusion Chamber (CFDC). Measured number concentrations of ice nuclei (IN) varied from frequent values of 0.01 per liter to more than 10 per liter. Residuals of airborne droplets and ice crystals were collected through a counterflow virtual impactor (CVI). The compositions of individual atmospheric particles and the residuals were studied using Computer Controlled Scanning Electron Microscopy with Energy Dispersive X-ray analysis (CCSEM/EDX) and Scanning Transmission X-ray Microscopy coupled with Near Edge X-ray Absorption Fine Structure spectroscopy (STXM/NEXAFS). Chemical analysis of cloud particle residuals collected during an episode of high ice nucleation suggests that both size and composition may influence aerosol's ability to act as IN. The STXM/NEXAFS chemical composition maps of individual residuals have characteristic structures of either inorganic or black carbon cores coated by organic materials. In a separate flight, particle samples from a biomass burning plume were collected. Although it has previously been suggested that episodes of biomass burning contribute to increased numbers of highly effective ice nuclei, in this episode we observed that only a small fraction were effective ice nuclei. Most of the particles from the biomass plume episode were smaller in size and were composed of homogeneous organic material without identifiable cores.

  18. Stellar yields of rotating first stars. I. Yields of weak supernovae and abundances of carbon-enhanced hyper-metal-poor stars

    SciTech Connect (OSTI)

    Takahashi, Koh; Umeda, Hideyuki [Department of Astronomy, The University of Tokyo, Bunkyo, Tokyo 113-0033 (Japan); Yoshida, Takashi, E-mail: ktakahashi@astron.s.u-tokyo.ac.jp [Yukawa Institute for Theoretical Physics, Kyoto University, Kitashirakawa-Oiwakecho, Sakyo-Ku, Kyoto 606-8502 (Japan)

    2014-10-10

    We perform a stellar evolution simulation of first stars and calculate stellar yields from the first supernovae. The initial masses are taken from 12 to 140 M {sub ?} to cover the whole range of core-collapse supernova progenitors, and stellar rotation is included, which results in efficient internal mixing. A weak explosion is assumed in supernova yield calculations, thus only outer distributed matter, which is not affected by the explosive nucleosynthesis, is ejected in the models. We show that the initial mass and the rotation affect the explosion yield. All the weak explosion models have abundances of [C/O] larger than unity. Stellar yields from massive progenitors of >40-60 M {sub ?} show enhancement of Mg and Si. Rotating models yield abundant Na and Al, and Ca is synthesized in nonrotating heavy massive models of >80 M {sub ?}. We fit the stellar yields to the three most iron-deficient stars and constrain the initial parameters of the mother progenitor stars. The abundance pattern in SMSS 03136708 is well explained by 50-80 M {sub ?} nonrotating models, rotating 30-40 M {sub ?} models well fit the abundance of HE 0107-5240, and both nonrotating and rotating 15-40 M {sub ?} models explain HE 1327-2326. The presented analysis will be applicable to other carbon-enhanced hyper-metal-poor stars observed in the future. The abundance analyses will give valuable information about the characteristics of the first stars.

  19. Angular Distributions of Fragments Originating from the Spontaneous Fission of Oriented Nuclei and Problem of the Conservation of the Spin Projection onto the Symmetry Axis of a Fissile Nucleus

    SciTech Connect (OSTI)

    Kadmensky, S.G.; Rodionova, L.V. [Voronezh State University, Universitetskaya pl. 1, Voronezh, 394693 (Russian Federation)

    2005-09-01

    The concept of transition fission states, which was successfully used to describe the angular distributions of fragments for the spontaneous and low-energy induced fission of axisymmetric nuclei, proves to be correct if the spin projection onto the symmetry axis of a fissile nucleus is an integral of the motion for the external region from the descent of the fissile nucleus from the external fission barrier to the scission point. Upon heating a fissile nucleus in this region to temperatures of T {approx_equal} 1 MeV (this is predicted by many theoretical models of the fission process), the Coriolis interaction uniformly mixes the possible projections of the fissile-nucleus spin for the case of low spin values, this leading to the loss of memory about transition fission states in the asymptotic region where the angular distributions of fragments are formed. Within quantum-mechanical fission theory, which takes into account deviations from A. Bohr's formula, the angular distributions of fragments are calculated for spontaneously fissile nuclei aligned by an external magnetic field at ultralow temperatures, and it is shown that an analysis of experimental angular distributions of fragments would make it possible to solve the problem of spin-projection conservation for fissile nuclei in the external region.

  20. Environmental Survey Report for ORNL: Small Mammal Abundance and Distribution Survey Oak Ridge National Environmental Research Park 2009 - 2010

    SciTech Connect (OSTI)

    Giffen, Neil R; Reasor, R. Scott; Campbell, Claire L.

    2009-12-01

    This report summarizes a 1-year small mammal biodiversity survey conducted on the Oak Ridge National Environmental Research Park (OR Research Park). The task was implemented through the Oak Ridge National Laboratory (ORNL) Natural Resources Management Program and included researchers from the ORNL Environmental Sciences Division, interns in the Oak Ridge Institute for Science and Education Higher Education Research Experiences Program, and ORNL Environmental Protection Services staff. Eight sites were surveyed reservation wide. The survey was conducted in an effort to determine species abundance and diversity of small mammal populations throughout the reservation and to continue the historical inventory of small mammal presence for biodiversity records. This data collection effort was in support of the approved Wildlife Management Plan for the Oak Ridge Reservation, a major goal of which is to maintain and enhance wildlife biodiversity on the Reservation. Three of the sites (Poplar Creek, McNew Hollow, and Deer Check Station Field) were previously surveyed during a major natural resources inventory conducted in 1996. Five new sites were included in this study: Bearden Creek, Rainy Knob (Natural Area 21), Gum Hollow, White Oak Creek and Melton Branch. The 2009-2010 small mammal surveys were conducted from June 2009 to July 2010 on the Oak Ridge National Environmental Research Park (OR Research Park). The survey had two main goals: (1) to determine species abundance and diversity and (2) to update historical records on the OR Research Park. The park is located on the Department of Energy-owned Oak Ridge Reservation, which encompasses 13,580 ha. The primary focus of the study was riparian zones. In addition to small mammal sampling, vegetation and coarse woody debris samples were taken at certain sites to determine any correlations between habitat and species presence. During the survey all specimens were captured and released using live trapping techniques including Sherman and pitfall traps. In total 227 small mammals representing nine species were captured during the course of the study. The most common species found in the study was the white-footed mouse (Peromyscus leucopus). The least common species found were the deer mouse (Peromyscus maniculatus), meadow jumping mouse (Zapus hudsonius), woodland vole (Microtus pinetorum), and northern short-tailed shrew (Blarina brevicauda).