National Library of Energy BETA

Sample records for boundary layer height

  1. ARM - Measurement - Planetary boundary layer height

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

    govMeasurementsPlanetary boundary layer height 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 : Planetary boundary layer height Top of the planetary boundary layer; also known as depth or height of the mixing layer. Categories Atmospheric State Instruments The above measurement is considered scientifically relevant for the following instruments. Refer to the datastream (netcdf) file headers of each

  2. Boundary Layer Structure:

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

    Boundary Layer Structure: a comparison between methods and sites Thiago Biscaro Suzane de Sá Jae-In Song Shaoyue "Emily" Qiu Mentors: Virendra Ghate and Ewan O'Connor July 24 2015 1 st ever ARM Summer Training Outline * IntroducQon * Methodology * Results - SGP - MAO - Comparison between the 2 sites * Conclusions INTRODUCTION Focus: esQmates of PBL height Boundary Layer: "The boUom layer of the troposphere that is in contact with the surface of the earth." (AMS, Glossary of

  3. Planetary Boundary Layer from AERI and MPL (Dataset) | Data Explorer

    Office of Scientific and Technical Information (OSTI)

    Because radiative heating and cooling of the surface strongly affect the PBL top height, ... thus improve model parameterizations and our understanding of boundary-layer processes. ...

  4. Planetary Boundary Layer from AERI and MPL

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

    Sawyer, Virginia

    2014-02-13

    The distribution and transport of aerosol emitted to the lower troposphere is governed by the height of the planetary boundary layer (PBL), which limits the dilution of pollutants and influences boundary-layer convection. Because radiative heating and cooling of the surface strongly affect the PBL top height, it follows diurnal and seasonal cycles and may vary by hundreds of meters over a 24-hour period. The cap the PBL imposes on low-level aerosol transport makes aerosol concentration an effective proxy for PBL height: the top of the PBL is marked by a rapid transition from polluted, well-mixed boundary-layer air to the cleaner, more stratified free troposphere. Micropulse lidar (MPL) can provide much higher temporal resolution than radiosonde and better vertical resolution than infrared spectrometer (AERI), but PBL heights from all three instruments at the ARM SGP site are compared to one another for validation. If there is agreement among them, the higher-resolution remote sensing-derived PBL heights can accurately fill in the gaps left by the low frequency of radiosonde launches, and thus improve model parameterizations and our understanding of boundary-layer processes.

  5. Boundary Layer Cloud Turbulence Characteristics

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

    Boundary Layer Cloud Turbulence Characteristics Virendra Ghate Bruce Albrecht Parameter Observational Readiness (/10) Modeling Need (/10) Cloud Boundaries 9 9 Cloud Fraction Variance Skewness Up/Downdraft coverage Dominant Freq. signal Dissipation rate ??? Observation-Modeling Interface

  6. Microsoft Word - Group 1 Boundary Layer(RS).docx

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

    Planetary Boundary Layer Height: A Comparison of Estimation Methods and Sites Report Participants: Thiago Biscaro, Instituto Nacional de Pesquisas Espaciais, Brazil Suzane S. de Sá, Harvard University Jae-In Song, Yonsei University, Korea Instructors: Virendra Ghate, Argonne National Laboratory Ewan O'Connor, Finnish Meteorological Institute, University of Reading July 2015 Group 1, July 2015, ARM Summer Training and Science Applications 1 1.0 Planetary Boundary Layer Height: A Comparison of

  7. ARM - PI Product - Planetary Boundary Layer from AERI and MPL

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

    ProductsPlanetary Boundary Layer from AERI and MPL 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 : Planetary Boundary Layer from AERI and MPL The distribution and transport of aerosol emitted to the lower troposphere is governed by the height of the planetary boundary layer (PBL), which limits the dilution of pollutants and influences boundary-layer convection. Because radiative heating and cooling of

  8. Cyclone separator having boundary layer turbulence control

    DOE Patents [OSTI]

    Krishna, Coimbatore R.; Milau, Julius S.

    1985-01-01

    A cyclone separator including boundary layer turbulence control that is operable to prevent undue build-up of particulate material at selected critical areas on the separator walls, by selectively varying the fluid pressure at those areas to maintain the momentum of the vortex, thereby preventing particulate material from inducing turbulence in the boundary layer of the vortical fluid flow through the separator.

  9. Size distributions of boundary-layer clouds

    SciTech Connect (OSTI)

    Stull, R.; Berg, L.; Modzelewski, H.

    1996-04-01

    Scattered fair-weather clouds are triggered by thermals rising from the surface layer. Not all surface layer air is buoyant enough to rise. Also, each thermal has different humidities and temperatures, resulting in interthermal variability of their lifting condensation levels (LCL). For each air parcel in the surface layer, it`s virtual potential temperature and it`s LCL height can be computed.

  10. Modeling the summertime Arctic cloudy boundary layer

    SciTech Connect (OSTI)

    Curry, J.A.; Pinto, J.O.; McInnes, K.L.

    1996-04-01

    Global climate models have particular difficulty in simulating the low-level clouds during the Arctic summer. Model problems are exacerbated in the polar regions by the complicated vertical structure of the Arctic boundary layer. The presence of multiple cloud layers, a humidity inversion above cloud top, and vertical fluxes in the cloud that are decoupled from the surface fluxes, identified in Curry et al. (1988), suggest that models containing sophisticated physical parameterizations would be required to accurately model this region. Accurate modeling of the vertical structure of multiple cloud layers in climate models is important for determination of the surface radiative fluxes. This study focuses on the problem of modeling the layered structure of the Arctic summertime boundary-layer clouds and in particular, the representation of the more complex boundary layer type consisting of a stable foggy surface layer surmounted by a cloud-topped mixed layer. A hierarchical modeling/diagnosis approach is used. A case study from the summertime Arctic Stratus Experiment is examined. A high-resolution, one-dimensional model of turbulence and radiation is tested against the observations and is then used in sensitivity studies to infer the optimal conditions for maintaining two separate layers in the Arctic summertime boundary layer. A three-dimensional mesoscale atmospheric model is then used to simulate the interaction of this cloud deck with the large-scale atmospheric dynamics. An assessment of the improvements needed to the parameterizations of the boundary layer, cloud microphysics, and radiation in the 3-D model is made.

  11. ARM - Field Campaign - Lower Atmospheric Boundary Layer Experiment

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

    Related Campaigns 2013 Lower Atmospheric Boundary Layer Experiment 2013.05.28, Turner, SGP ... Lead Scientist : David Turner For data sets, see below. Abstract Boundary layer turbulence ...

  12. A dual mass flux framework for boundary layer convection

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

    A dual mass flux framework for boundary layer convection Neggers, Roel European Centre for Medium-range Weather Forecasts (ECMWF) Category: Modeling A new convective boundary layer...

  13. Boundary Layer Cloudiness Parameterizations Using ARM Observations

    SciTech Connect (OSTI)

    Bruce Albrecht

    2004-09-15

    This study used DOE ARM data and facilities to: (1) study macroscopic properties of continental stratus clouds at SGP and the factors controlling these properties, (2) develop a scientific basis for understanding the processes responsible for the formation of boundary layer clouds using ARM observations in conjunction with simple parametric models and LES, and (3) evaluate cumulus cloud characteristics retrieved from the MMCR operating at TWP-Nauru. In addition we have used high resolution 94 GHz observations of boundary layer clouds and precipitation to: (1) develop techniques for using high temporal resolution Doppler velocities to study large-eddy circulations and turbulence in boundary layer clouds and estimate the limitations of using current and past MMCR data for boundary layer cloud studies, (2) evaluate the capability and limitations of the current MMCR data for estimating reflectivity, vertical velocities, and spectral under low- signal-to-noise conditions associated with weak no n-precipitating clouds, (3) develop possible sampling modes for the new MMCR processors to allow for adequate sampling of boundary layer clouds, and (4) retrieve updraft and downdraft structures under precipitating conditions.

  14. ARM - Field Campaign - Boundary Layer Cloud IOP

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

    govCampaignsBoundary Layer Cloud IOP Campaign Links Campaign Images 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 Campaign : Boundary Layer Cloud IOP 2005.07.11 - 2005.08.07 Lead Scientist : William Shaw For data sets, see below. Abstract Investigators from Pacific Northwest National Laboratory, in collaboration with scientists from a number of other institutions, carried out a month of intensive measurements at

  15. Thick diffusion limit boundary layer test problems

    SciTech Connect (OSTI)

    Bailey, T. S.; Warsa, J. S.; Chang, J. H.; Adams, M. L.

    2013-07-01

    We develop two simple test problems that quantify the behavior of computational transport solutions in the presence of boundary layers that are not resolved by the spatial grid. In particular we study the quantitative effects of 'contamination' terms that, according to previous asymptotic analyses, may have a detrimental effect on the solutions obtained by both discontinuous finite element (DFEM) and characteristic-method (CM) spatial discretizations, at least for boundary layers caused by azimuthally asymmetric incident intensities. Few numerical results have illustrated the effects of this contamination, and none have quantified it to our knowledge. Our test problems use leading-order analytic solutions that should be equal to zero in the problem interior, which means the observed interior solution is the error introduced by the contamination terms. Results from DFEM solutions demonstrate that the contamination terms can cause error propagation into the problem interior for both orthogonal and non-orthogonal grids, and that this error is much worse for non-orthogonal grids. This behavior is consistent with the predictions of previous analyses. We conclude that these boundary layer test problems and their variants are useful tools for the study of errors that are introduced by unresolved boundary layers in diffusive transport problems. (authors)

  16. Bursting frequency prediction in turbulent boundary layers

    SciTech Connect (OSTI)

    LIOU,WILLIAM W.; FANG,YICHUNG

    2000-02-01

    The frequencies of the bursting events associated with the streamwise coherent structures of spatially developing incompressible turbulent boundary layers were predicted using global numerical solution of the Orr-Sommerfeld and the vertical vorticity equations of hydrodynamic stability problems. The structures were modeled as wavelike disturbances associated with the turbulent mean flow. The global method developed here involves the use of second and fourth order accurate finite difference formula for the differential equations as well as the boundary conditions. An automated prediction tool, BURFIT, was developed. The predicted resonance frequencies were found to agree very well with previous results using a local shooting technique and measured data.

  17. Temporal variability of the trade wind inversion: Measured with a boundary layer vertical profiler. Master's thesis

    SciTech Connect (OSTI)

    Grindinger, C.M.

    1992-05-01

    This study uses Hawaiian Rainband Project (HaRP) data, from the summer of 1991, to show a boundary layer wind profiler can be used to measure the trade wind inversion. An algorithm has been developed for the profiler that objectively measures the depth of the moist oceanic boundary layer. The Hilo inversion, measured by radiosonde, is highly correlated with the moist oceanic boundary layer measured by the profiler at Paradise Park. The inversion height on windward Hawaii is typically 2253 + or - 514 m. The inversion height varies not only on a daily basis, but on less than an hourly basis. It has a diurnal, as well as a three to four day cycle. There appears to be no consistent relationship between inversion height and precipitation. Currently, this profiler is capable of making high frequency (12 minute) measurements of the inversion base variation, as well as other features.

  18. SUPERSONIC SHEAR INSTABILITIES IN ASTROPHYSICAL BOUNDARY LAYERS

    SciTech Connect (OSTI)

    Belyaev, Mikhail A.; Rafikov, Roman R., E-mail: rrr@astro.princeton.edu [Department of Astrophysical Sciences, Princeton University, Ivy Lane, Princeton, NJ 08540 (United States)

    2012-06-20

    Disk accretion onto weakly magnetized astrophysical objects often proceeds via a boundary layer (BL) that forms near the object's surface, in which the rotation speed of the accreted gas changes rapidly. Here, we study the initial stages of formation for such a BL around a white dwarf or a young star by examining the hydrodynamical shear instabilities that may initiate mixing and momentum transport between the two fluids of different densities moving supersonically with respect to each other. We find that an initially laminar BL is unstable to two different kinds of instabilities. One is an instability of a supersonic vortex sheet (implying a discontinuous initial profile of the angular speed of the gas) in the presence of gravity, which we find to have a growth rate of order (but less than) the orbital frequency. The other is a sonic instability of a finite width, supersonic shear layer, which is similar to the Papaloizou-Pringle instability. It has a growth rate proportional to the shear inside the transition layer, which is of order the orbital frequency times the ratio of stellar radius to the BL thickness. For a BL that is thin compared to the radius of the star, the shear rate is much larger than the orbital frequency. Thus, we conclude that sonic instabilities play a dominant role in the initial stages of nonmagnetic BL formation and give rise to very fast mixing between disk gas and stellar fluid in the supersonic regime.

  19. ARM - Field Campaign - 2013 Lower Atmospheric Boundary Layer...

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

    Lower Atmospheric Boundary Layer Experiment 2012.09.17, Turner, SGP Comments? We would ... Lead Scientist : David Turner For data sets, see below. Abstract Instruments were deployed ...

  20. "Lidar Investigations of Aerosol, Cloud, and Boundary Layer Properties...

    Office of Scientific and Technical Information (OSTI)

    Technical Report: "Lidar Investigations of Aerosol, Cloud, and Boundary Layer Properties Over the ARM ACRF Sites" Citation Details In-Document Search Title: "Lidar Investigations ...

  1. Stable Boundary Layer Education Field Campaign Summary

    Office of Scientific and Technical Information (OSTI)

    ... (derived from the temperature) and water vapor mixing ratio retrieved from the AERI ... The other panels show time- height cross sections of potential temperature, water vapor ...

  2. RACORO continental boundary layer cloud investigations. Part...

    Office of Scientific and Technical Information (OSTI)

    large-scale forcings Observation-based modeling case studies of continental boundary ... The cases developed are available to the general modeling community for studying ...

  3. Simulation of High Reynolds Number Turbulent Boundary Layers | Argonne

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

    Leadership Computing Facility A visualization of the velocity in a boundary layer at Reynolds numbers up to 2100 shows the growth of the turbulence structures out into the free stream as it evolves downstream (to the right) and the intermittent uneven boundary of the turbulent region. Juan Sillero, Universidad Politécnica de Madrid. Simulation of High Reynolds Number Turbulent Boundary Layers PI Name: Robert Moser PI Email: rmoser@ices.utexas.edu Institution: University of Texas at Austin

  4. ARM - Field Campaign - Stable Boundary Layer Education (StaBLE)

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

    govCampaignsStable Boundary Layer Education (StaBLE) Campaign Links Final Campaign Summary 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 Campaign : Stable Boundary Layer Education (StaBLE) 2011.10.01 - 2014.05.31 Lead Scientist : David Turner For data sets, see below. Abstract The properties and processing in the nocturnal stable boundary layer are not well understood, which makes it difficult to represent

  5. Marine Boundary Layer Cloud Observations in the Azores (Journal...

    Office of Scientific and Technical Information (OSTI)

    Marine Boundary Layer Cloud Observations in the Azores Citation Details ... Publication Date: 2012-11-01 OSTI Identifier: 1059795 Report Number(s): BNL--98829-2012-JA Journal ID: ISSN ...

  6. Estimation of the mixing layer height over a high altitude site in Central Himalayan region by using Doppler lidar

    SciTech Connect (OSTI)

    Shukla, K. K.; Phanikumar, D. V.; Newsom, Rob K.; Kumar, Niranjan; Ratnam, Venkat; Naja, M.; Singh, Narendra

    2014-03-01

    A Doppler lidar was installed at Manora Peak, Nainital (29.4 N; 79.2 E, 1958 amsl) to estimate mixing layer height for the first time by using vertical velocity variance as basic measurement parameter for the period September-November 2011. Mixing layer height is found to be located ~0.57 +/- 0.1and 0.45 +/- 0.05km AGL during day and nighttime, respectively. The estimation of mixing layer height shows good correlation (R>0.8) between different instruments and with different methods. Our results show that wavelet co-variance transform is a robust method for mixing layer height estimation.

  7. Determination of the Schottky barrier height of ferromagnetic contacts to few-layer phosphorene

    SciTech Connect (OSTI)

    Anugrah, Yoska; Robbins, Matthew C.; Koester, Steven J.; Crowell, Paul A.

    2015-03-09

    Phosphorene, the 2D analogue of black phosphorus, is a promising material for studying spin transport due to its low spin-orbit coupling and its ½ nuclear spin, which could allow the study of hyperfine effects. In this work, the properties of permalloy (Py) and cobalt (Co) contacts to few-layer phosphorene are presented. The Schottky barrier height was extracted and determined as a function of gate bias. Flat-band barrier heights, relative to the valence band edge, of 110 meV and 200 meV were determined for Py and Co, respectively. These results are important for future studies of spin transport in phosphorene.

  8. ARM - Field Campaign - Boundary Layer CO2 Using CW Lidar

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

    govCampaignsBoundary Layer CO2 Using CW Lidar Comments? We would love to hear from you! Send us a note below or call us at 1-888-ARM-DATA. Send Campaign : Boundary Layer CO2 Using CW Lidar 2005.05.21 - 2005.05.24 Lead Scientist : Michael Dobbs Abstract Overflights Underway at ACRF Southern Great Plains Site (M.Dobbs/J.Liljegren) Science collaborators at ITT Industries and the National Aeronautics and Space Administration (NASA) Langley Research Center (LaRC) conducted flights over the Central

  9. Lower Atmospheric Boundary Layer Experiment (LABLE) Final Campaign Report

    SciTech Connect (OSTI)

    Klein, P; Bonin, TA; Newman, JF; Turner, DD; Chilson, P; Blumberg, WG; Mishra, S; Wainwright, CE; Carney, M; Jacobsen, EP; Wharton, S

    2015-11-01

    The Lower Atmospheric Boundary Layer Experiment (LABLE) included two measurement campaigns conducted at the Atmospheric Radiation Measurement (ARM) Southern Great Plains site in Oklahoma during 2012 and 2013. LABLE was designed as a multi-phase, low-cost collaboration among the University of Oklahoma, the National Severe Storms Laboratory, Lawrence Livermore National Laboratory, and the ARM program. A unique aspect was the role of graduate students in LABLE. They served as principal investigators and took the lead in designing and conducting experiments using different sampling strategies to best resolve boundary-layer phenomena.

  10. Lidar Investigation of Tropical Nocturnal Boundary Layer Aerosols and Cloud Macrophysics

    SciTech Connect (OSTI)

    Manoj, M. G.; Devara, PC S.; Taraphdar, Sourav

    2013-10-01

    Observational evidence of two-way association between nocturnal boundary layer aerosols and cloud macrophysical properties under different meteorological conditions is reported in this paper. The study has been conducted during 2008-09 employing a high space-time resolution polarimetric micro-pulse lidar over a tropical urban station in India. Firstly, the study highlights the crucial role of boundary layer aerosols and background meteorology on the formation and structure of low-level stratiform clouds in the backdrop of different atmospheric stability conditions. Turbulent mixing induced by the wind shear at the station, which is associated with a complex terrain, is found to play a pivotal role in the formation and structural evolution of nocturnal boundary layer clouds. Secondly, it is shown that the trapping of energy in the form of outgoing terrestrial radiation by the overlying low-level clouds can enhance the aerosol mixing height associated with the nocturnal boundary layer. To substantiate this, the long-wave heating associated with cloud capping has been quantitatively estimated in an indirect way by employing an Advanced Research Weather Research and Forecasting (WRF-ARW) model version 2.2 developed by National Center for Atmospheric Research (NCAR), Colorado, USA, and supplementary data sets; and differentiated against other heating mechanisms. The present investigation as well establishes the potential of lidar remote-sensing technique in exploring some of the intriguing aspects of the cloud-environment relationship.

  11. Marine boundary layer structure as observed by A-train satellites

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

    Luo, Tao; Wang, Zhien; Zhang, Damao; Chen, Bing

    2016-05-13

    The marine boundary layer (MBL) structure is important to the marine low cloud processes, and the exchange of heat, momentum, and moisture between oceans and the low atmosphere. This study examines the MBL structure over the eastern Pacific region and further explores the controlling factors of MBL structure over the global oceans with a new 4-year satellite-based data set. The MBL top (boundary layer height, BLH) and the mixing layer height (MLH) were identified using the MBL aerosol lidar backscattering from the CALIPSO (Cloud–Aerosol Lidar and Infrared Pathfinder Satellite Observations). Results showed that the MBL is generally decoupled with MLH ∕ BLHmore » ratio ranging from  ∼  0.5 to  ∼  0.8 over the eastern Pacific Ocean region. The MBL decoupling magnitude is mainly controlled by estimated inversion strength (EIS), which in turn controls the cloud top entrainment process. The systematic differences between drizzling and non-drizzling stratocumulus tops also show dependence on EIS. This may be related to the meso-scale circulations or gravity wave in the MBL. Further analysis indicates that the MBL shows a similar decoupled structure for clear-sky and cumulus-cloud-topped conditions, but is better mixed under stratiform cloud breakup and overcast conditions.« less

  12. Marine boundary layer structure as observed by A-train satellites

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

    Luo, Tao; Wang, Zhien; Zhang, Damao; Chen, Bing

    2016-05-13

    Here, the marine boundary layer (MBL) structure is important to the marine low cloud processes, and the exchange of heat, momentum, and moisture between oceans and the low atmosphere. This study examines the MBL structure over the eastern Pacific region and further explores the controlling factors of MBL structure over the global oceans with a new 4-year satellite-based data set. The MBL top (boundary layer height, BLH) and the mixing layer height (MLH) were identified using the MBL aerosol lidar backscattering from the CALIPSO (Cloud–Aerosol Lidar and Infrared Pathfinder Satellite Observations). Results showed that the MBL is generally decoupled withmore » MLH/BLH ratio ranging from ~0.5 to ~0.8 over the eastern Pacific Ocean region. The MBL decoupling magnitude is mainly controlled by estimated inversion strength (EIS), which in turn controls the cloud top entrainment process. The systematic differences between drizzling and non-drizzling stratocumulus tops also show dependence on EIS. This may be related to the meso-scale circulations or gravity wave in the MBL. Further analysis indicates that the MBL shows a similar decoupled structure for clear-sky and cumulus-cloud-topped conditions, but is better mixed under stratiform cloud breakup and overcast conditions.« less

  13. Edge Plasma Boundary Layer Generated By Kink Modes in Tokamaks

    SciTech Connect (OSTI)

    L.E. Zakharov

    2010-11-22

    This paper describes the structure of the electric current generated by external kink modes at the plasma edge using the ideally conducting plasma model. It is found that the edge current layer is created by both wall touching and free boundary kink modes. Near marginal stability, the total edge current has a universal expression as a result of partial compensation of the ?-functional surface current by the bulk current at the edge. The resolution of an apparent paradox with the pressure balance across the plasma boundary in the presence of the surface currents is provided.

  14. Vertical Velocities in Continental Boundary Layer Stratocumulus Clouds

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

    Velocities in Continental Boundary Layer Stratocumulus Clouds Virendra Ghate Bruce Albrecht and Pavlos Kollias Why BL Stratocumulus?? * Extensive Coverage - Cover ~24% of earth's surface - Persist of long time-scales * Impact on radiation budget - High SW albedo compared to land or ocean Klein and Hartmann 1993 But Why Continental Clouds? * They do exist - Monthly cloud fraction can vary from 10% to 23% * Impact on pollution & Diurnal Cycle - Affect pollutant venting out of BL & Aerosol

  15. Improving Subtropical Boundary Layer Cloudiness in the 2011 NCEP GFS

    SciTech Connect (OSTI)

    Fletcher, J. K.; Bretherton, Christopher S.; Xiao, Heng; Sun, Ruiyu N.; Han, J.

    2014-09-23

    The current operational version of National Centers for Environmental Prediction (NCEP) Global Forecasting System (GFS) shows significant low cloud bias. These biases also appear in the Coupled Forecast System (CFS), which is developed from the GFS. These low cloud biases degrade seasonal and longer climate forecasts, particularly of short-wave cloud radiative forcing, and affect predicted sea surface temperature. Reducing this bias in the GFS will aid the development of future CFS versions and contributes to NCEP's goal of unified weather and climate modelling. Changes are made to the shallow convection and planetary boundary layer parameterisations to make them more consistent with current knowledge of these processes and to reduce the low cloud bias. These changes are tested in a single-column version of GFS and in global simulations with GFS coupled to a dynamical ocean model. In the single-column model, we focus on changing parameters that set the following: the strength of shallow cumulus lateral entrainment, the conversion of updraught liquid water to precipitation and grid-scale condensate, shallow cumulus cloud top, and the effect of shallow convection in stratocumulus environments. Results show that these changes improve the single-column simulations when compared to large eddy simulations, in particular through decreasing the precipitation efficiency of boundary layer clouds. These changes, combined with a few other model improvements, also reduce boundary layer cloud and albedo biases in global coupled simulations.

  16. LABLE: A multi-institutional, student-led, atmospheric boundary layer experiment

    SciTech Connect (OSTI)

    Klein, P.; Bonin, T. A.; Newman, J. F.; Turner, D. D.; Chilson, P. B.; Wainwright, C. E.; Blumberg, W. G.; Mishra, S.; Carney, M.; Jacobsen, E. P.; Wharton, Sonia; Newsom, Rob K.

    2015-10-23

    This paper presents an overview of the Lower Atmospheric Boundary Layer Experiment (LABLE), which included two measurement campaigns conducted at the Atmospheric Radiation Measurement (ARM) Southern Great Plains site in Oklahoma during 2012 and 2013. LABLE was conducted as a collaborative effort between the University of Oklahoma (OU), the National Severe Storms Laboratory, Lawrence Livermore National Laboratory (LLNL), and the ARM program. LABLE can be considered unique in that it was designed as a multi-phase, low-cost, multi-agency collaboration. Graduate students served as principal investigators and took the lead in designing and conducting experiments aimed at examining boundary-layer processes. The main objective of LABLE was to study turbulent phenomena in the lowest 2 km of the atmosphere over heterogeneous terrain using a variety of novel atmospheric profiling techniques. Several instruments from OU and LLNL were deployed to augment the suite of in-situ and remote sensing instruments at the ARM site. The complementary nature of the deployed instruments with respect to resolution and height coverage provides a near-complete picture of the dynamic and thermodynamic structure of the atmospheric boundary layer. This paper provides an overview of the experiment including i) instruments deployed, ii) sampling strategies, iii) parameters observed, and iv) student involvement. To illustrate these components, the presented results focus on one particular aspect of LABLE, namely the study of the nocturnal boundary layer and the formation and structure of nocturnal low-level jets. During LABLE, low-level jets were frequently observed and they often interacted with mesoscale atmospheric disturbances such as frontal passages.

  17. ARM: X-Band Scanning ARM Cloud Radar (XSACR) Boundary Layer RHI...

    Office of Scientific and Technical Information (OSTI)

    Title: ARM: X-Band Scanning ARM Cloud Radar (XSACR) Boundary Layer RHI Scan X-Band Scanning ARM Cloud Radar (XSACR) Boundary Layer RHI Scan Authors: Dan Nelson ; Joseph Hardin ; ...

  18. Characterization of structural response to hypersonic boundary-layer transition

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

    Riley, Zachary B.; Deshmukh, Rohit; Miller, Brent A.; McNamara, Jack J.; Casper, Katya M.

    2016-05-24

    The inherent relationship between boundary-layer stability, aerodynamic heating, and surface conditions makes the potential for interaction between the structural response and boundary-layer transition an important and challenging area of study in high-speed flows. This paper phenomenologically explores this interaction using a fundamental two-dimensional aerothermoelastic model under the assumption of an aluminum panel with simple supports. Specifically, an existing model is extended to examine the impact of transition onset location, transition length, and transitional overshoot in heat flux and fluctuating pressure on the structural response of surface panels. Transitional flow conditions are found to yield significantly increased thermal gradients, and theymore » can result in higher maximum panel temperatures compared to turbulent flow. Results indicate that overshoot in heat flux and fluctuating pressure reduces the flutter onset time and increases the strain energy accumulated in the panel. Furthermore, overshoot occurring near the midchord can yield average temperatures and peak displacements exceeding those experienced by the panel subject to turbulent flow. Lastly, these results suggest that fully turbulent flow does not always conservatively predict the thermo-structural response of surface panels.« less

  19. Clear-sky and Cloudy Boundary Layers Virendra P. Ghate Argonne National Laboratory

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

    Clear-sky and Cloudy Boundary Layers Virendra P. Ghate Argonne National Laboratory Define Boundary Layer Stull (1988) defined the atmospheric boundary layer as "the part of the troposphere that is directly influenced by the presence of the earth's surface, and responds to surface forcings with a time scale of about an hour or less." Typical Boundary Layer Depths and time-scales Scenario Time/Length scale Clear-air Convective 30 mins/1 km Cumulus Topped Boundary Layer 30 mins/1 km

  20. Transforming the representation of the boundary layer and low clouds for high-resolution regional climate modeling: Final report

    SciTech Connect (OSTI)

    Huang, Hsin-Yuan; Hall, Alex

    2013-07-24

    the mostly dry mountain-breeze circulations force an additional component that results in semi-diurnal variations near the coast. A series of numerical tests, however, reveal sensitivity of the simulations to the choice of vertical grid, limiting the possibility of solid quantitative statements on the amplitudes and phases of the diurnal and semidiurnal components across the domain. According to our experiments, the Mellor-Yamada-Nakanishi-Niino (MYNN) boundary layer scheme and the WSM6 microphysics scheme is the combination of schemes that performs best. For that combination, mean cloud cover, liquid water path, and cloud depth are fairly wellsimulated, while mean cloud top height remains too low in comparison to observations. Both microphysics and boundary layer schemes contribute to the spread in liquid water path and cloud depth, although the microphysics contribution is slightly more prominent. Boundary layer schemes are the primary contributors to cloud top height, degree of adiabaticity, and cloud cover. Cloud top height is closely related to surface fluxes and boundary layer structure. Thus, our study infers that an appropriate tuning of cloud top height would likely improve the low-cloud representation in the model. Finally, we show that entrainment governs the degree of adiabaticity, while boundary layer decoupling is a control on cloud cover. In the intercomparison study using WRF single-column model experiments, most parameterizations show a poor agreement of the vertical boundary layer structure when compared with large-eddy simulation models. We also implement a new Total-Energy/Mass- Flux boundary layer scheme into the WRF model and evaluate its ability to simulate both stratocumulus and shallow cumulus clouds. Result comparisons against large-eddy simulation show that this advanced parameterization based on the new Eddy-Diffusivity/Mass-Flux approach provides a better performance than other boundary layer parameterizations.

  1. Nocturnal Low-Level-Jet-Dominated Atmospheric Boundary Layer Observed by a Doppler Lidar Over Oklahoma City during JU2003

    SciTech Connect (OSTI)

    Wang, Yansen; Klipp, Cheryl L.; Garvey, Dennis M.; Ligon, David; Williamson, Chatt C.; Chang, Sam S.; Newsom, Rob K.; Calhoun, Ron

    2007-12-01

    Boundary layer wind data observed by a Doppler lidar and sonic anemometers during the mornings of three intensive observational periods (IOP2, IOP3, and IOP7) of the Joint Urban 2003 (JU2003) field experiment are analyzed to extract the mean and turbulent characteristics of airflow over Oklahoma City, Oklahoma. A strong nocturnal low-level jet (LLJ) dominated the flow in the boundary layer over the measurement domain from midnight to the morning hours. Lidar scans through the LLJ taken after sunrise indicate that the LLJ elevation shows a gradual increase of 25-100 m over the urban area relative to that over the upstream suburban area. The mean wind speed beneath the jet over the urban area is about 10%-15% slower than that over the suburban area. Sonic anemometer observations combined with Doppler lidar observations in the urban and suburban areas are also analyzed to investigate the boundary layer turbulence production in the LLJ-dominated atmospheric boundary layer. The turbulence kinetic energy was higher over the urban domain mainly because of the shear production of building surfaces and building wakes. Direct transport of turbulent momentum flux from the LLJ to the urban street level was very small because of the relatively high elevation of the jet. However, since the LLJ dominated the mean wind in the boundary layer, the turbulence kinetic energy in the urban domain is correlated directly with the LLJ maximum speed and inversely with its height. The results indicate that the jet Richardson number is a reasonably good indicator for turbulent kinetic energy over the urban domain in the LLJ-dominated atmospheric boundary layer.

  2. Structure of the nocturnal boundary layer over a complex terrain

    SciTech Connect (OSTI)

    Parker, M.J. ); Raman, S. . Dept. of Marine, Earth and Atmospheric Sciences)

    1992-01-01

    The complex nature of the nocturnal boundary layer (NBL) has been shown extensively in the literature Project STABLE was conducted in 1988 to study NBL turbulence and diffusion over the complex terrain of the Savannah River Site (SRS) near Augusta, Georgia. The third night of the study was particularly interesting because of the unusual phenomena observed in the structure of the NBL. Further analyses of microscale and mesoscale data from this night are presented using data from SRS network of eight 61 m towers over 900 km{sup 2}, from six launches of an instrumented tethersonde, from permanent SRL meteorological instrumentation at seven levels of the 304 m (1,000 ft) WJBF-TV tower near SRS, and additional data collected at 36 m (CC) by North Carolina State University (NCSU) including a one dimensional sonic anemometer, fine wire thermocouple, and a three dimensional propeller anemometer. Also, data from the nearby Plant Vogtle nuclear power plant observation tower and the National Weather Service at Augusta's Bush Field (AGS) are presented. The passage of a mesoscale phenomenon, defined as a microfront (with an explanation of the nomenclature used), and a vertical composite schematic of the NBL which shows dual low level wind maxima, dual inversions, and a persistent, elevated turbulent layer over a complex terrain are described.

  3. Structure of the nocturnal boundary layer over a complex terrain

    SciTech Connect (OSTI)

    Parker, M.J.; Raman, S.

    1992-08-01

    The complex nature of the nocturnal boundary layer (NBL) has been shown extensively in the literature Project STABLE was conducted in 1988 to study NBL turbulence and diffusion over the complex terrain of the Savannah River Site (SRS) near Augusta, Georgia. The third night of the study was particularly interesting because of the unusual phenomena observed in the structure of the NBL. Further analyses of microscale and mesoscale data from this night are presented using data from SRS network of eight 61 m towers over 900 km{sup 2}, from six launches of an instrumented tethersonde, from permanent SRL meteorological instrumentation at seven levels of the 304 m (1,000 ft) WJBF-TV tower near SRS, and additional data collected at 36 m (CC) by North Carolina State University (NCSU) including a one dimensional sonic anemometer, fine wire thermocouple, and a three dimensional propeller anemometer. Also, data from the nearby Plant Vogtle nuclear power plant observation tower and the National Weather Service at Augusta`s Bush Field (AGS) are presented. The passage of a mesoscale phenomenon, defined as a microfront (with an explanation of the nomenclature used), and a vertical composite schematic of the NBL which shows dual low level wind maxima, dual inversions, and a persistent, elevated turbulent layer over a complex terrain are described.

  4. Studies of planetary boundary layer by infrared thermal imagery

    SciTech Connect (OSTI)

    Albina, Bogdan; Dimitriu, Dan Gheorghe Gurlui, Silviu Octavian; Cazacu, Marius Mihai; Timofte, Adrian

    2014-11-24

    The IR camera is a relatively novel device for remote sensing of atmospheric thermal processes from the Planetary Boundary Layer (PBL) based on measurements of the infrared radiation. Infrared radiation is energy radiated by the motion of atoms and molecules on the surface of aerosols, when their temperature is more than absolute zero. The IR camera measures directly the intensity of radiation emitted by aerosols which is converted by an imaging sensor into an electric signal, resulting a thermal image. Every image pixel that corresponds to a specific radiance is pre-processed to identify the brightness temperature. The thermal infrared imaging radiometer used in this study, NicAir, is a precision radiometer developed by Prata et al. The device was calibrated for the temperature range of 270–320 K and using a calibration table along with image processing software, important information about variations in temperature can be extracted from acquired IR images. The PBL is the lowest layer of the troposphere where the atmosphere interacts with the ground surfaces. The importance of PBL lies in the fact that it provides a finite but varying volume in which pollutants can disperse. The aim of this paper is to analyze the PBL altitude and thickness variations over Iasi region using the IR imaging camera as well as its behavior from day to night and thermal processes occurring in PBL.

  5. Sensitivity of Boundary-layer and Deep Convective Cloud Simulations to

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

    Vertical Resolution Sensitivity of Boundary-layer and Deep Convective Cloud Simulations to Vertical Resolution Cheng, Anning Langley Research Center Xu, Kuan-Man NASA Langley Research Center Category: Modeling This study investigates the effects of vertical resolution on the simulation of boundary-layer and deep convective clouds using a cloud resolving model (CRM). A CRM usually uses a vertical grid spacing less than 100 m to simulate boundary layer clouds such as shallow cumuli and

  6. Simulation of Post-Frontal Boundary Layers Observed During the ARM 2000 Cloud IOP

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

    Simulation of Post-Frontal Boundary Layers Observed During the ARM 2000 Cloud IOP D. B. Mechem and Y. L. Kogan Cooperative Institute for Mesoscale Meteorological Studies University of Oklahoma Norman, Oklahoma M. Poellot University of North Dakota Grand Forks, North Dakota Introduction Large-eddy simulation (LES) models have been widely employed in the study of radiatively forced cloud topped boundary layers (CTBL). These boundary layers are typically well mixed and characterized by a sharp jump

  7. Further development and testing of a second-order bulk boundary layer model. Master's thesis

    SciTech Connect (OSTI)

    Krasner, R.D.

    1993-05-03

    A one-layer bulk boundary layer model is developed. The model predicts the mixed layer values of the potential temperature, mixing ratio, and u- and v-momentum. The model also predicts the depth of the boundary layer and the vertically integrated turbulence kinetic energy (TKE). The TKE is determined using a second-order closure that relates the rate of dissipation to the TKE. The fractional area covered by rising motion sigma and the entrainment rate (E) are diagnostically determined. The model is used to study the clear convective boundary layer (CBL) using data from the Wangara, Australia boundary layer experiment. The Wangara data is also used as an observation base to validate model results. A further study is accomplished by simulating the planetary boundary layer (PBL) over an ocean surface. This study is designed to find the steady-state solutions of the prognostic variable.

  8. Marine boundary layer structure as observed by space-based Lidar

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

    Luo, T.; Wang, Z.; Zhang, D.

    2015-12-03

    The marine boundary layer (MBL) structure is important to the exchange of heat, momentum, and moisture between oceans and the low atmosphere and to the marine low cloud processes. This paper explores MBL structure over the eastern Pacific region with a new 4 year satellite-based dataset. The MBL aerosol lidar backscattering from the CALIPSO (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations) was used to identify the MBL top (BLH) and the mixing layer height (MLH). Results showed that MBL is generally decoupled with MLH / BLH ratio ranging from ? 0.5 to ? 0.8 and the MBL decoupling magnitude ismoremainly controlled by estimated inversion strength (EIS) that affects the cloud top entrainment process. The systematic differences between drizzling and non-drizzling stratocumulus tops, which may relate to the meso-scale circulations or gravity wave in MBL, also show dependence on EIS. Further analysis indicated that the MBL shows similar decoupled structure for clear sky and cumulus cloud-topped conditions, but is better mixed under stratiform cloud breakup and overcast conditions.less

  9. ARM: Boundary-layer height data with CEIL (Dataset) | Data Explorer

    Office of Scientific and Technical Information (OSTI)

    Sponsoring Org: USDOE Office of Science (SC), Biological and Environmental Research (BER) Country of Publication: United States Availability: ORNL Language: English Subject: 54 ...

  10. DOE/SC-ARM/TR-132 Planetary Boundary Layer (PBL) Height Value

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

    ... Figure 4 shows an example quicklook for a case classified as NRL by the Liu-Liang method. Here, there is only one panel as the wind speed and LLJ do not enter into the ...

  11. Sensitivity of a global climate model to the critical Richardson number in the boundary layer parameterization

    SciTech Connect (OSTI)

    Zhang, Ning; Liu, Yangang; Gao, Zhiqiu; Li, Dan

    2015-04-27

    The critical bulk Richardson number (Ricr) is an important parameter in planetary boundary layer (PBL) parameterization schemes used in many climate models. This paper examines the sensitivity of a Global Climate Model, the Beijing Climate Center Atmospheric General Circulation Model, BCC_AGCM to Ricr. The results show that the simulated global average of PBL height increases nearly linearly with Ricr, with a change of about 114 m for a change of 0.5 in Ricr. The surface sensible (latent) heat flux decreases (increases) as Ricr increases. The influence of Ricr on surface air temperature and specific humidity is not significant. The increasing Ricr may affect the location of the Westerly Belt in the Southern Hemisphere. Further diagnosis reveals that changes in Ricr affect stratiform and convective precipitations differently. Increasing Ricr leads to an increase in the stratiform precipitation but a decrease in the convective precipitation. Significant changes of convective precipitation occur over the inter-tropical convergence zone, while changes of stratiform precipitation mostly appear over arid land such as North Africa and Middle East.

  12. Sensitivity of a global climate model to the critical Richardson number in the boundary layer parameterization

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

    Zhang, Ning; Liu, Yangang; Gao, Zhiqiu; Li, Dan

    2015-04-27

    The critical bulk Richardson number (Ricr) is an important parameter in planetary boundary layer (PBL) parameterization schemes used in many climate models. This paper examines the sensitivity of a Global Climate Model, the Beijing Climate Center Atmospheric General Circulation Model, BCC_AGCM to Ricr. The results show that the simulated global average of PBL height increases nearly linearly with Ricr, with a change of about 114 m for a change of 0.5 in Ricr. The surface sensible (latent) heat flux decreases (increases) as Ricr increases. The influence of Ricr on surface air temperature and specific humidity is not significant. The increasingmore » Ricr may affect the location of the Westerly Belt in the Southern Hemisphere. Further diagnosis reveals that changes in Ricr affect stratiform and convective precipitations differently. Increasing Ricr leads to an increase in the stratiform precipitation but a decrease in the convective precipitation. Significant changes of convective precipitation occur over the inter-tropical convergence zone, while changes of stratiform precipitation mostly appear over arid land such as North Africa and Middle East.« less

  13. Local Correlations and Multi-Fractal Behaviour in Marine Boundary Layer Cloud Dynamics

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

    Local Correlations and Multi-Fractal Behaviour in Marine Boundary Layer Cloud Dynamics N. Kitova and M. A. Mikhalev Institute of Electronics Bulgarian Academy of Sciences Sofia 1784, Bulgaria K. Ivanova Department of Meteorology Pennsylvania State University University Park, Pennsylvania M. Ausloos Institute of Physics University of Liège Liège, Belgium T. P. Ackerman Pacific Northwest National Laboratory Richland, Washington Introduction The marine boundary layer (MBL) cloud dynamics is

  14. Boundary Layer The U.S. Department of Energy's Atmospheric Radiation

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

    Aerosol, and Precipitation in the Marine Boundary Layer The U.S. Department of Energy's Atmospheric Radiation Measurement (ARM) Climate Research Facility is sponsoring a 20-month field study on Graciosa Island in the Azores. Scientists involved in the Clouds, Aerosol, and Precipitation in the Marine Boundary Layer field campaign are using the ARM Mobile Facility-a portable climate observatory-to study low-level clouds and aerosol in a marine environment. Collaborators from the Regional

  15. A boundary-layer cloud study using Southern Great Plains Cloud and radiation testbed (CART) data

    SciTech Connect (OSTI)

    Albrecht, B.; Mace, G.; Dong, X.; Syrett, W.

    1996-04-01

    Boundary layer clouds-stratus and fairweather cumulus - are closely coupled involves the radiative impact of the clouds on the surface energy budget and the strong dependence of cloud formation and maintenance on the turbulent fluxes of heat and moisture in the boundary layer. The continuous data collection at the Southern Great Plains (SGP) Cloud and Radiation Testbed (CART) site provides a unique opportunity to study components of the coupling processes associated with boundary layer clouds and to provide descriptions of cloud and boundary layer structure that can be used to test parameterizations used in climate models. But before the CART data can be used for process studies and parameterization testing, it is necessary to evaluate and validate data and to develop techniques for effectively combining the data to provide meaningful descriptions of cloud and boundary layer characteristics. In this study we use measurements made during an intensive observing period we consider a case where low-level stratus were observed at the site for about 18 hours. This case is being used to examine the temporal evolution of cloud base, cloud top, cloud liquid water content, surface radiative fluxes, and boundary layer structure. A method for inferring cloud microphysics from these parameters is currently being evaluated.

  16. Combustion-turbulence interaction in the turbulent boundary layer over a hot surface

    SciTech Connect (OSTI)

    Ng, T.T.; Cheng, R.K.; Robben, F.; Talbot, L.

    1982-01-01

    The turbulence-combustion interaction in a reacting turbulent boundary layer over a heated flat plate was studied. Ethylene/air mixture with equivalence ratio of 0.35 was used. The free stream velocity was 10.5 m/s and the wall temperature was 1250/sup 0/K. Combustion structures visualization was provided by high-speed schlieren photographs. Fluid density statistics were deduced from Rayleigh scattering intensity measurements. A single-component laser Doppler velocimetry system was used to obtain mean and root-mean-square velocity distributions, the Reynolds stress, the streamwise and the cross-stream turbulent kinetic energy diffusion, and the production of turbulent kinetic energy by Reynolds stress. The combustion process was dominated by large-scale turbulent structures of the boundary layer. Combustion causes expansion of the boundary layer. No overall self-similarity is observed in either the velocity or the density profiles. Velocity fluctuations were increased in part of the boundary layer and the Reynolds stress was reduced. The turbulent kinetic energy diffusion pattern was changed significantly and a modification of the boundary layer assumption will be needed when dealing with this problem analytically. 11 figures, 1 table.

  17. Direct Simulation of a Zero-pressure-gradient Turbulent Boundary Layer up

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

    to Reθ = 6650 | Argonne Leadership Computing Facility a Zero-pressure-gradient Turbulent Boundary Layer up to Reθ = 6650 Authors: Sillero, J., Jiménez, J., Moser, R.D., Malaya, N.P A direct simulation of an incompressible zero-pressure-gradient turbulent boundary layer over a flat plate is performed in Reθ = 1100-6650 (Reτ ≈ 2025), matching the range of the available numerical channels. The logarithmic region and the separation of scales are clearly observed. Proper turbulent inflow

  18. Hybrid OpenMP-MPI Turbulent Boundary Layer Code Over 32k Cores | Argonne

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

    Leadership Computing Facility OpenMP-MPI Turbulent Boundary Layer Code Over 32k Cores Authors: Sillero, J., Borrell, G., Jimenez, J., Moser, RD A hybrid OpenMP-MPI code has been developed and optimized for Blue Gene/P in order to perform a direct numerical simulation of a zero-pressure-gradient turbulent boundary layer at high Reynolds numbers. OpenMP is becoming the standard application programming interface for shared memory platforms, offering simplicity and portability. For architectures

  19. “Lidar Investigations of Aerosol, Cloud, and Boundary Layer Properties Over the ARM ACRF Sites”

    SciTech Connect (OSTI)

    Ferrare, Richard; Turner, David

    2015-01-13

    Project goals; Characterize the aerosol and ice vertical distributions over the ARM NSA site, and in particular to discriminate between elevated aerosol layers and ice clouds in optically thin scattering layers; Characterize the water vapor and aerosol vertical distributions over the ARM Darwin site, how these distributions vary seasonally, and quantify the amount of water vapor and aerosol that is above the boundary layer; Use the high temporal resolution Raman lidar data to examine how aerosol properties vary near clouds; Use the high temporal resolution Raman lidar and Atmospheric Emitted Radiance Interferometer (AERI) data to quantify entrainment in optically thin continental cumulus clouds; and Use the high temporal Raman lidar data to continue to characterize the turbulence within the convective boundary layer and how the turbulence statistics (e.g., variance, skewness) is correlated with larger scale variables predicted by models.

  20. Large Eddy Simulation of Stable Boundary Layer Turbulent Processes in Complex Terrain

    SciTech Connect (OSTI)

    Eric D. Skyllingstad

    2005-01-26

    Research was performed using a turbulence boundary layer model to study the behavior of cold, dense flows in regions of complex terrain. Results show that flows develop a balance between turbulent entrainment of warm ambient air and dense, cold air created by surface cooling. Flow depth and strength is a function of downslope distance, slope angle and angle changes, and the ambient air temperature.

  1. Interactions between a tropical mixed boundary layer and cumulus convection in a radiative-convective model

    SciTech Connect (OSTI)

    Dean, C.L.

    1993-05-01

    This report details a radiative-convective model, combining previously developed cumulus, stable cloud and radiation parameterizations with a boundary layer scheme, which was developed in the current study. The cloud model was modified to incorporate the effects of both small and large clouds. The boundary layer model was adapted from a mixed layer model was only slightly modified to couple it with the more sophisticated cloud model. The model was tested for a variety of imposed divergence profiles, which simulate the regions of the tropical ocean from approximately the intertropical Convergence Zone (ITCZ) to the subtropical high region. The sounding used to initialize the model for most of the runs is from the trade wind region of ATEX. For each experiment, the model was run with a timestep of 300 seconds for a period of 7 days.

  2. RACORO long-term, systematic aircraft observations of boundary layer clouds

    SciTech Connect (OSTI)

    Vogelmann, A.M.; McFarquhar, G.; Ogren, J.; Turner, D. D.; Comstock, J. M.; Feingold, G.; Long, C. N.; Jonsson, H. H.; Bucholtz, A.; Collins, D. R.; Diskin, G.; Gerber, H.; Lawson, R. P.; Woods, R. K.; Hubbe, J.; Tomlinson, J.; Schmid, B.

    2010-06-27

    Our knowledge of boundary layer cloud processes is insufficient to resolve pressing scientific problems. Boundary layer clouds often have liquid-water paths (LWPs) less than 100 gm{sup 2}, which are defined here as being 'thin' Clouds with Low Optical Water Depths (CLOWD). This type of cloud is common globally, and the Earth's radiative energy balance is particularly sensitive to small changes in their optical properties. However, it is difficult to retrieve accurately their cloud properties via remote sensing because they are tenuous and often occur in partly cloudy skies. This interferes with our ability to obtain the routine, long-term statistics needed to improve their representation in climate models. To address this problem, in-situ data are needed to investigate cloud processes and to evaluate and refine existing retrieval algorithms. Coordinated by the ARM Aerial Facility (AAF), the Routine AAF CLOWD Optical Radiative Observations (RACORO) field campaign conducted long-term, systematic flights in boundary layer, liquid-water clouds over the ARM Southern Great Plains (SGP) site between 22 January and 30 June 2009. This was the first time that a long-term aircraft campaign was undertaken for systematic in-situ sampling of cloud properties. Using the CIRPAS Twin Otter aircraft equipped with a comprehensive set of instruments to measure solar and thermal radiation, cloud microphysics, aerosol properties and atmospheric state, the RACORO team logged an unprecedented 59 flights and 259 research hours above the SGP site. Data gathered during the RACORO campaign will provide researchers with a statistically relevant data set of boundary-layer cloud and aerosol properties for future study. These data can be used to validate retrieval algorithms and support process studies and model simulations of boundary layer clouds and, in particular, CLOWD-type clouds. In addition to cloud observations, complementary clear-sky flight patterns were conducted to map the surface

  3. Adaptive step-size algorithm for Fourier beam-propagation method with absorbing boundary layer of auto-determined width

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

    Learn, R.; Feigenbaum, E.

    2016-05-27

    Two algorithms that enhance the utility of the absorbing boundary layer are presented, mainly in the framework of the Fourier beam-propagation method. One is an automated boundary layer width selector that chooses a near-optimal boundary size based on the initial beam shape. Furthermore, the second algorithm adjusts the propagation step sizes based on the beam shape at the beginning of each step in order to reduce aliasing artifacts.

  4. Raman lidar/AERI PBL Height Product

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

    Ferrare, Richard

    2012-12-14

    Planetary Boundary Layer (PBL) heights have been computed using potential temperature profiles derived from Raman lidar and AERI measurements. Raman lidar measurements of the rotational Raman scattering from nitrogen and oxygen are used to derive vertical profiles of potential temperature. AERI measurements of downwelling radiance are used in a physical retrieval approach (Smith et al. 1999, Feltz et al. 1998) to derive profiles of temperature and water vapor. The Raman lidar and AERI potential temperature profiles are merged to create a single potential temperature profile for computing PBL heights. PBL heights were derived from these merged potential temperature profiles using a modified Heffter (1980) technique that was tailored to the SGP site (Della Monache et al., 2004). PBL heights were computed on an hourly basis for the period January 1, 2009 through December 31, 2011. These heights are provided as meters above ground level.

  5. Raman lidar/AERI PBL Height Product

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

    Ferrare, Richard

    Planetary Boundary Layer (PBL) heights have been computed using potential temperature profiles derived from Raman lidar and AERI measurements. Raman lidar measurements of the rotational Raman scattering from nitrogen and oxygen are used to derive vertical profiles of potential temperature. AERI measurements of downwelling radiance are used in a physical retrieval approach (Smith et al. 1999, Feltz et al. 1998) to derive profiles of temperature and water vapor. The Raman lidar and AERI potential temperature profiles are merged to create a single potential temperature profile for computing PBL heights. PBL heights were derived from these merged potential temperature profiles using a modified Heffter (1980) technique that was tailored to the SGP site (Della Monache et al., 2004). PBL heights were computed on an hourly basis for the period January 1, 2009 through December 31, 2011. These heights are provided as meters above ground level.

  6. Highly mobile type II twin boundary in Ni-Mn-Ga five-layered martensite

    SciTech Connect (OSTI)

    Sozinov, A.; Lanska, N.; Soroka, A.; Straka, L.

    2011-09-19

    Twin relationships and stress-induced reorientation were studied in Ni{sub 2}Mn{sub 1.14}Ga{sub 0.86} single crystal with five-layered modulated martensite crystal structure. Very low twinning stress of about 0.1 MPa was found for twin boundaries which deviated a few degrees from the (011) crystallographic plane. However, twin boundaries oriented exactly parallel to the (011) plane exhibited considerably higher level of twinning stress, above 1 MPa. X-ray diffraction experiments and calculations based on approximation of the martensite crystal lattice as a tetragonal lattice with a slight monoclinic distortion identified the two different kinds of twin interfaces as type II and type I twin boundaries.

  7. Experimental investigation of sound generation by a protuberance in a laminar boundary layer

    SciTech Connect (OSTI)

    Kobayashi, M.; Asai, M.; Inasawa, A. [Department of Aerospace Engineering, Tokyo Metropolitan University, 6-6 Asahigaoka, Hino, Tokyo 191-0065 (Japan)

    2014-08-15

    Sound radiation from a two-dimensional protuberance glued on the wall in a laminar boundary layer was investigated experimentally at low Mach numbers. When the protuberance was as high as the boundary-layer thickness, a feedback-loop mechanism set in between protuberance-generated sound and Tollmien-Schlichting (T-S) waves generated by the leading-edge receptivity to the upstream-propagating sound. Although occurrence of a separation bubble immediately upstream of the protuberance played important roles in the evolution of instability waves into vortices interacting with the protuberance, the frequency of tonal vortex sound was determined by the selective amplification of T-S waves in the linear instability stage upstream of the separation bubble and was not affected by the instability of the separation bubble.

  8. Lidar Investigations of Aerosol, Cloud, and Boundary Layer Properties Over the ARM ACRF Sites

    SciTech Connect (OSTI)

    Turner, David D.; Ferrare, Richard

    2015-01-13

    The systematic and routine measurements of aerosol, water vapor, and clouds in the vertical column above the Atmospheric Radiation Measurement (ARM) sites from surface-based remote sensing systems provides a unique and comprehensive data source that can be used to characterize the boundary layer (i.e., the lowest 3 km of the atmosphere) and its evolution. New algorithms have been developed to provide critical datasets from ARM instruments, and these datasets have been used in long-term analyses to better understand the climatology of water vapor and aerosol over Darwin, the turbulent structure of the boundary layer and its statistical properties over Oklahoma, and to better determine the distribution of ice and aerosol particles over northern Alaska.

  9. Problems of laminar-turbulent transition control in a boundary layer

    SciTech Connect (OSTI)

    Fedorov, A.V.; Levchenko, V. I.; Tumin, A.M. Moscow Physical-Technical Institute, )

    1991-03-01

    The overview of laminar-turbulent transition control compares different methods of transition control for swept-wing streams. The types of unstable disturbances in boundary layer are listed, and flow stabilization is described in terms of small disturbances. The control of the transition zone is based on the description of background disturbances, their transition into instability waves, and their linear and nonlinear amplifications. Specific references cite the applications to Tollmien-Schlichting waves, crossflow instability near an aircraft's leading edge, and unstable disturbances in a boundary layer over a curved surface. Methods of active control or wave cancellation to deal with the problem are listed including localized periodic heating, the introduction of vibrations, or the use of suction-blowing. The results of the comparative overview are of interest to aircraft and other aerospace applications to reduce drag and improve fuel efficiency. 111 refs.

  10. Characterization of Radar Boundary Layer Data Collected During the 2001 Multi-Frequency Radar IOP

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

    Characterization of Radar Boundary Layer Data Collected During the 2001 Multi-Frequency Radar IOP A. Khandwalla, N. Majurec, and S. M. Sekelsky University of Massachusetts Amherst, Massachusetts C. R. Williams and K. S. Gage National Oceanic and Atmospheric Administration Aeronomy Laboratory Boulder, Colorado Introduction Ground-based radar measurements of insect clutter at Ka-band (35 GHz) and W-band (95 GHz) were collected over an extended period during the 2001 multi-frequency radar (MFR)

  11. Regional Scale Surface CO2 Exchange Estimates Using a Boundary Layer Budget

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

    Method over the Southern Great Plains Regional Scale Surface CO2 Exchange Estimates Using a Boundary Layer Budget Method over the Southern Great Plains Williams, Ian University of Chicago Riley, William Lawrence Berkeley National Laboratory Berry, Joseph Carnegie Inst.of Washington Torn, Margaret Lawrence Berkeley National Laboratory Fischer, Marc Lawrence Berkeley National Laboratory Category: Atmospheric State and Surface Concentration gradients of CO2 and H2O at the transition between the

  12. Long-term Observations of the Convective Boundary Layer Using Insect Radar Returns at the SGP ARM Climate Research Facility

    SciTech Connect (OSTI)

    Chandra, A S; Kollias, P; Giangrande, S E; Klein, S A

    2009-08-20

    A long-term study of the turbulent structure of the convective boundary layer (CBL) at the U.S. Department of Energy Atmospheric Radiation Measurement Program (ARM) Southern Great Plains (SGP) Climate Research Facility is presented. Doppler velocity measurements from insects occupying the lowest 2 km of the boundary layer during summer months are used to map the vertical velocity component in the CBL. The observations cover four summer periods (2004-08) and are classified into cloudy and clear boundary layer conditions. Profiles of vertical velocity variance, skewness, and mass flux are estimated to study the daytime evolution of the convective boundary layer during these conditions. A conditional sampling method is applied to the original Doppler velocity dataset to extract coherent vertical velocity structures and to examine plume dimension and contribution to the turbulent transport. Overall, the derived turbulent statistics are consistent with previous aircraft and lidar observations. The observations provide unique insight into the daytime evolution of the convective boundary layer and the role of increased cloudiness in the turbulent budget of the subcloud layer. Coherent structures (plumes-thermals) are found to be responsible for more than 80% of the total turbulent transport resolved by the cloud radar system. The extended dataset is suitable for evaluating boundary layer parameterizations and testing large-eddy simulations (LESs) for a variety of surface and cloud conditions.

  13. An enriched finite element model with q-refinement for radiative boundary layers in glass cooling

    SciTech Connect (OSTI)

    Mohamed, M. Shadi; Seaid, Mohammed; Trevelyan, Jon; Laghrouche, Omar

    2014-02-01

    Radiative cooling in glass manufacturing is simulated using the partition of unity finite element method. The governing equations consist of a semi-linear transient heat equation for the temperature field and a stationary simplified P{sub 1} approximation for the radiation in non-grey semitransparent media. To integrate the coupled equations in time we consider a linearly implicit scheme in the finite element framework. A class of hyperbolic enrichment functions is proposed to resolve boundary layers near the enclosure walls. Using an industrial electromagnetic spectrum, the proposed method shows an immense reduction in the number of degrees of freedom required to achieve a certain accuracy compared to the conventional h-version finite element method. Furthermore the method shows a stable behaviour in treating the boundary layers which is shown by studying the solution close to the domain boundaries. The time integration choice is essential to implement a q-refinement procedure introduced in the current study. The enrichment is refined with respect to the steepness of the solution gradient near the domain boundary in the first few time steps and is shown to lead to a further significant reduction on top of what is already achieved with the enrichment. The performance of the proposed method is analysed for glass annealing in two enclosures where the simplified P{sub 1} approximation solution with the partition of unity method, the conventional finite element method and the finite difference method are compared to each other and to the full radiative heat transfer as well as the canonical Rosseland model.

  14. Boundary layer modeling of reactive flow over a porous surface with angled injection

    SciTech Connect (OSTI)

    Liu, Shiling; Fotache, Catalin G.; Hautman, Donald J.; Ochs, Stuart S. [United Technologies Research Center, MS 129-29, 411 Silver Lane, East Hartford, CT 06108 (United States); Chao, Beei-Huan [Department of Mechanical Engineering, University of Hawaii at Manoa, Honolulu, HI 96822 (United States)

    2008-08-15

    An analytical model was developed to investigate the dynamics of nonpremixed flames in a shear layer established between a mainstream flow of fuel-rich combustion products and a porous surface with an angled injection of air. In the model, a one-step overall chemical reaction was employed, together with boundary layer conservation equations solved using similarity solutions. Parametric studies were performed to understand the effects of equivalence ratio, temperature, and mass flow rate of the fuel and air streams on the flame standoff distance, surface temperature, and heat flux at the surface. The analytical model predictions were compared with computational fluid dynamics results obtained using the FLUENT commercial code for both the laminar and the turbulent flow models. Qualitative agreement in surface temperature was observed. Finally, the flame stability limits predicted by the model were compared with available experimental data and found to agree qualitatively, as well. (author)

  15. Pressure fluctuations beneath instability wavepackets and turbulent spots in a hypersonic boundary layer

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

    Casper, Katya M.; Beresh, Steven J.; Schneider, Steven P.

    2014-09-09

    To investigate the pressure-fluctuation field beneath turbulent spots in a hypersonic boundary layer, a study was conducted on the nozzle wall of the Boeing/AFOSR Mach-6 Quiet Tunnel. Controlled disturbances were created by pulsed-glow perturbations based on the electrical breakdown of air. Under quiet-flow conditions, the nozzle-wall boundary layer remains laminar and grows very thick over the long nozzle length. This allows the development of large disturbances that can be well-resolved with high-frequency pressure transducers. A disturbance first grows into a second-mode instability wavepacket that is concentrated near its own centreline. Weaker disturbances are seen spreading from the centre. The wavesmore » grow and become nonlinear before breaking down to turbulence. The breakdown begins in the core of the packets where the wave amplitudes are largest. Second-mode waves are still evident in front of and behind the breakdown point and can be seen propagating in the spanwise direction. The turbulent core grows downstream, resulting in a spot with a classical arrowhead shape. Behind the spot, a low-pressure calmed region develops. However, the spot is not merely a localized patch of turbulence; instability waves remain an integral part. Limited measurements of naturally occurring disturbances show many similar characteristics. From the controlled disturbance measurements, the convection velocity, spanwise spreading angle, and typical pressure-fluctuation field were obtained.« less

  16. THE SIMULATION OF FINE SCALE NOCTURNAL BOUNDARY LAYER MOTIONS WITH A MESO-SCALE ATMOSPHERIC MODEL

    SciTech Connect (OSTI)

    Werth, D.; Kurzeja, R.; Parker, M.

    2009-04-02

    A field project over the Atmospheric Radiation Measurement-Clouds and Radiation Testbed (ARM-CART) site during a period of several nights in September, 2007 was conducted to explore the evolution of the low-level jet (LLJ). Data was collected from a tower and a sodar and analyzed for turbulent behavior. To study the full range of nocturnal boundary layer (NBL) behavior, the Regional Atmospheric Modeling System (RAMS) was used to simulate the ARM-CART NBL field experiment and validated against the data collected from the site. This model was run at high resolution, and is ideal for calculating the interactions among the various motions within the boundary layer and their influence on the surface. The model reproduces adequately the synoptic situation and the formation and dissolution cycles of the low-level jet, although it suffers from insufficient cloud production and excessive nocturnal cooling. The authors suggest that observed heat flux data may further improve the realism of the simulations both in the cloud formation and in the jet characteristics. In a higher resolution simulation, the NBL experiences motion on a range of timescales as revealed by a wavelet analysis, and these are affected by the presence of the LLJ. The model can therefore be used to provide information on activity throughout the depth of the NBL.

  17. Pressure fluctuations beneath instability wavepackets and turbulent spots in a hypersonic boundary layer

    SciTech Connect (OSTI)

    Casper, Katya M.; Beresh, Steven J.; Schneider, Steven P.

    2014-09-09

    To investigate the pressure-fluctuation field beneath turbulent spots in a hypersonic boundary layer, a study was conducted on the nozzle wall of the Boeing/AFOSR Mach-6 Quiet Tunnel. Controlled disturbances were created by pulsed-glow perturbations based on the electrical breakdown of air. Under quiet-flow conditions, the nozzle-wall boundary layer remains laminar and grows very thick over the long nozzle length. This allows the development of large disturbances that can be well-resolved with high-frequency pressure transducers. A disturbance first grows into a second-mode instability wavepacket that is concentrated near its own centreline. Weaker disturbances are seen spreading from the centre. The waves grow and become nonlinear before breaking down to turbulence. The breakdown begins in the core of the packets where the wave amplitudes are largest. Second-mode waves are still evident in front of and behind the breakdown point and can be seen propagating in the spanwise direction. The turbulent core grows downstream, resulting in a spot with a classical arrowhead shape. Behind the spot, a low-pressure calmed region develops. However, the spot is not merely a localized patch of turbulence; instability waves remain an integral part. Limited measurements of naturally occurring disturbances show many similar characteristics. From the controlled disturbance measurements, the convection velocity, spanwise spreading angle, and typical pressure-fluctuation field were obtained.

  18. Retrieving 4-dimensional atmospheric boundary layer structure from surface observations and profiles over a single station

    SciTech Connect (OSTI)

    Pu, Zhaoxia

    2015-10-06

    Most routine measurements from climate study facilities, such as the Department of Energy’s ARM SGP site, come from individual sites over a long period of time. While single-station data are very useful for many studies, it is challenging to obtain 3-dimensional spatial structures of atmospheric boundary layers that include prominent signatures of deep convection from these data. The principal objective of this project is to create realistic estimates of high-resolution (~ 1km × 1km horizontal grids) atmospheric boundary layer structure and the characteristics of precipitating convection. These characteristics include updraft and downdraft cumulus mass fluxes and cold pool properties over a region the size of a GCM grid column from analyses that assimilate surface mesonet observations of wind, temperature, and water vapor mixing ratio and available profiling data from single or multiple surface stations. The ultimate goal of the project is to enhance our understanding of the properties of mesoscale convective systems and also to improve their representation in analysis and numerical simulations. During the proposed period (09/15/2011–09/14/2014) and the no-cost extension period (09/15/2014–09/14/2015), significant accomplishments have been achieved relating to the stated goals. Efforts have been extended to various research and applications. Results have been published in professional journals and presented in related science team meetings and conferences. These are summarized in the report.

  19. A simple stochastic quadrant model for the transport and deposition of particles in turbulent boundary layers

    SciTech Connect (OSTI)

    Jin, C.; Potts, I.; Reeks, M. W.

    2015-05-15

    We present a simple stochastic quadrant model for calculating the transport and deposition of heavy particles in a fully developed turbulent boundary layer based on the statistics of wall-normal fluid velocity fluctuations obtained from a fully developed channel flow. Individual particles are tracked through the boundary layer via their interactions with a succession of random eddies found in each of the quadrants of the fluid Reynolds shear stress domain in a homogeneous Markov chain process. In this way, we are able to account directly for the influence of ejection and sweeping events as others have done but without resorting to the use of adjustable parameters. Deposition rate predictions for a wide range of heavy particles predicted by the model compare well with benchmark experimental measurements. In addition, deposition rates are compared with those obtained from continuous random walk models and Langevin equation based ejection and sweep models which noticeably give significantly lower deposition rates. Various statistics related to the particle near wall behavior are also presented. Finally, we consider the model limitations in using the model to calculate deposition in more complex flows where the near wall turbulence may be significantly different.

  20. Clouds, aerosol, and precipitation in the Marine Boundary Layer: An ARM mobile facility deployment

    SciTech Connect (OSTI)

    Wood, Robert; Luke, Ed; Wyant, Matthew; Bretherton, Christopher S.; Remillard, Jasmine; Kollias, Pavlos; Fletcher, Jennifer; Stemmler, Jayson; deSzoeke, S.; Yuter, Sandra; Miller, Matthew; Mechem, David; Tselioudis, George; Chiu, Christine; Mann, Julia; O Connor, Ewan; Hogan, Robin; Dong, Xiquan; Miller, Mark; Ghate, Virendra; Jefferson, Anne; Min, Qilong; Minnis, Patrick; Palinkonda, Rabindra; Albrecht, Bruce; Hannay, Cecile; Lin, Yanluan

    2014-04-27

    The Clouds, Aerosol, and Precipitation in the Marine Boundary Layer (CAP-MBL) deployment at Graciosa Island in the Azores generated a 21-month (April 2009-December 2010) comprehensive dataset documenting clouds, aerosols, and precipitation using the Atmospheric Radiation Measurement Program (ARM) Mobile Facility (AMF). The scientific aim of the deployment is to gain improved understanding of the interactions of clouds, aerosols, and precipitation in the marine boundary layer. Graciosa Island straddles the boundary between the subtropics and midlatitudes in the Northeast Atlantic Ocean and consequently experiences a great diversity of meteorological and cloudiness conditions. Low clouds are the dominant cloud type, with stratocumulus and cumulus occurring regularly. Approximately half of all clouds contained precipitation detectable as radar echoes below the cloud base. Radar and satellite observations show that clouds with tops from 1-11 km contribute more or less equally to surface-measured precipitation at Graciosa. A wide range of aerosol conditions was sampled during the deployment consistent with the diversity of sources as indicated by back-trajectory analysis. Preliminary findings suggest important two-way interactions between aerosols and clouds at Graciosa, with aerosols affecting light precipitation and cloud radiative properties while being controlled in part by precipitation scavenging.The data from Graciosa are being compared with short-range forecasts made with a variety of models. A pilot analysis with two climate and two weather forecast models shows that they reproduce the observed time-varying vertical structure of lower-tropospheric cloud fairly well but the cloud-nucleating aerosol concentrations less well. The Graciosa site has been chosen to be a permanent fixed ARM site that became operational in October 2013.

  1. Clouds, aerosol, and precipitation in the Marine Boundary Layer: An ARM mobile facility deployment

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

    Wood, Robert; Luke, Ed; Wyant, Matthew; Bretherton, Christopher S.; Remillard, Jasmine; Kollias, Pavlos; Fletcher, Jennifer; Stemmler, Jayson; deSzoeke, S.; Yuter, Sandra; et al

    2014-04-27

    The Clouds, Aerosol, and Precipitation in the Marine Boundary Layer (CAP-MBL) deployment at Graciosa Island in the Azores generated a 21-month (April 2009-December 2010) comprehensive dataset documenting clouds, aerosols, and precipitation using the Atmospheric Radiation Measurement Program (ARM) Mobile Facility (AMF). The scientific aim of the deployment is to gain improved understanding of the interactions of clouds, aerosols, and precipitation in the marine boundary layer. Graciosa Island straddles the boundary between the subtropics and midlatitudes in the Northeast Atlantic Ocean and consequently experiences a great diversity of meteorological and cloudiness conditions. Low clouds are the dominant cloud type, with stratocumulusmore » and cumulus occurring regularly. Approximately half of all clouds contained precipitation detectable as radar echoes below the cloud base. Radar and satellite observations show that clouds with tops from 1-11 km contribute more or less equally to surface-measured precipitation at Graciosa. A wide range of aerosol conditions was sampled during the deployment consistent with the diversity of sources as indicated by back-trajectory analysis. Preliminary findings suggest important two-way interactions between aerosols and clouds at Graciosa, with aerosols affecting light precipitation and cloud radiative properties while being controlled in part by precipitation scavenging.The data from Graciosa are being compared with short-range forecasts made with a variety of models. A pilot analysis with two climate and two weather forecast models shows that they reproduce the observed time-varying vertical structure of lower-tropospheric cloud fairly well but the cloud-nucleating aerosol concentrations less well. The Graciosa site has been chosen to be a permanent fixed ARM site that became operational in October 2013.« less

  2. Clouds, Aerosols, and Precipitation in the Marine Boundary Layer: An Arm Mobile Facility Deployment

    SciTech Connect (OSTI)

    Wood, Robert; Wyant, Matthew; Bretherton, Christopher S.; Rémillard, Jasmine; Kollias, Pavlos; Fletcher, Jennifer; Stemmler, Jayson; de Szoeke, Simone; Yuter, Sandra; Miller, Matthew; Mechem, David; Tselioudis, George; Chiu, J. Christine; Mann, Julian A. L.; O’Connor, Ewan J.; Hogan, Robin J.; Dong, Xiquan; Miller, Mark; Ghate, Virendra; Jefferson, Anne; Min, Qilong; Minnis, Patrick; Palikonda, Rabindra; Albrecht, Bruce; Luke, Ed; Hannay, Cecile; Lin, Yanluan

    2015-03-01

    The Clouds, Aerosol, and Precipitation in the Marine Boundary Layer (CAP-MBL) 38 deployment at Graciosa Island in the Azores generated a 21 month (April 2009-December 2010) 39 comprehensive dataset documenting clouds, aerosols and precipitation using the Atmospheric 40 Radiation Measurement (ARM) Mobile Facility (AMF). The scientific aim of the deployment is 41 to gain improved understanding of the interactions of clouds, aerosols and precipitation in the 42 marine boundary layer. 43 Graciosa Island straddles the boundary between the subtropics and midlatitudes in the 44 Northeast Atlantic Ocean, and consequently experiences a great diversity of meteorological and 45 cloudiness conditions. Low clouds are the dominant cloud type, with stratocumulus and cumulus 46 occurring regularly. Approximately half of all clouds contained precipitation detectable as radar 47 echoes below the cloud base. Radar and satellite observations show that clouds with tops from 1-48 11 km contribute more or less equally to surface-measured precipitation at Graciosa. A wide 49 range of aerosol conditions was sampled during the deployment consistent with the diversity of 50 sources as indicated by back trajectory analysis. Preliminary findings suggest important two-way 51 interactions between aerosols and clouds at Graciosa, with aerosols affecting light precipitation 52 and cloud radiative properties while being controlled in part by precipitation scavenging. 53 The data from at Graciosa are being compared with short-range forecasts made a variety 54 of models. A pilot analysis with two climate and two weather forecast models shows that they 55 reproduce the observed time-varying vertical structure of lower-tropospheric cloud fairly well, 56 but the cloud-nucleating aerosol concentrations less well. The Graciosa site has been chosen to 57 be a long-term ARM site that became operational in October 2013.

  3. Model of the boundary layer of a vacuum-arc magnetic filter

    SciTech Connect (OSTI)

    Minotti, F.; Giuliani, L.; Grondona, D.; Della Torre, H.; Kelly, H.

    2013-03-21

    A model is developed to describe the electrostatic boundary layer in a positively biased magnetic filter in filtered arcs with low collisionality. The set of equations used includes the electron momentum equation, with an anomalous collision term due to micro-instabilities leading to Bohm diffusion, electron mass conservation, and Poisson equation. Analytical solutions are obtained, valid for the regimes of interest, leading to an explicit expression to determine the electron density current to the filter wall as a function of the potential of the filter and the ratio of electron density at the plasma to that at the filter wall. Using a set of planar and cylindrical probes it is verified experimentally that the mentioned ratio of electron densities remains reasonably constant for different magnetic field values and probe bias, which allows to obtain a closed expression for the current. Comparisons are made with the experimentally determined current collected at different sections of a positively biased straight filter.

  4. Pulsed Plasma with Synchronous Boundary Voltage for Rapid Atomic Layer Etching

    SciTech Connect (OSTI)

    Economou, Demetre J.; Donnelly, Vincent M.

    2014-05-13

    Atomic Layer ETching (ALET) of a solid with monolayer precision is a critical requirement for advancing nanoscience and nanotechnology. Current plasma etching techniques do not have the level of control or damage-free nature that is needed for patterning delicate sub-20 nm structures. In addition, conventional ALET, based on pulsed gases with long reactant adsorption and purging steps, is very slow. In this work, novel pulsed plasma methods with synchronous substrate and/or “boundary electrode” bias were developed for highly selective, rapid ALET. Pulsed plasma and tailored bias voltage waveforms provided controlled ion energy and narrow energy spread, which are critical for highly selective and damage-free etching. The broad goal of the project was to investigate the plasma science and engineering that will lead to rapid ALET with monolayer precision. A combined experimental-simulation study was employed to achieve this goal.

  5. RACORO Extended-Term Aircraft Observations of Boundary-Layer Clouds

    SciTech Connect (OSTI)

    Vogelmann, A. M.; McFarquhar, Greg; Ogren, John A.; Turner, David D.; Comstock, Jennifer M.; Feingold, G.; Long, Charles N.; Jonsson, Haf; Bucholtz, Anthony; Collins, Donald R.; Diskin, G. S.; Gerber, H.; Lawson, Paul; Woods, Roy; Andrews, Elizabeth; Yang, Hee-Jung; Chiu, Christine J.; Hartsock, Daniel; Hubbe, John M.; Lo, Chaomei; Marshak, A.; Monroe, Justin; McFarlane, Sally A.; Schmid, Beat; Tomlinson, Jason M.; Toto, Tami

    2012-06-30

    A first-of-a-kind, extended-term cloud aircraft campaign was conducted to obtain an in-situ statistical characterization of boundary-layer clouds needed to investigate cloud processes and refine retrieval algorithms. Coordinated by the Atmospheric Radiation Measurement (ARM) Aerial Facility (AAF), the Routine AAF Clouds with Low Optical Water Depths (CLOWD) Optical Radiative Observations (RACORO) field campaign operated over the ARM Southern Great Plains (SGP) site from 22 January to 30 June 2009, collecting 260 h of data during 59 research flights. A comprehensive payload aboard the Center for Interdisciplinary Remotely-Piloted Aircraft Studies (CIRPAS) Twin Otter aircraft measured cloud microphysics, solar and thermal radiation, aerosol properties, and atmospheric state parameters. Proximity to the SGP's extensive complement of surface measurements provides ancillary data that supports modeling studies and enables evaluating a variety of surface retrieval algorithms. The five-month duration enabled sampling a range of conditions associated with the seasonal transition from winter to summer. Although about two-thirds of the cloud flights occurred in May and June, boundary-layer cloud fields were sampled under a variety of environmental and aerosol conditions, with about 75% of the flights occurring in cumulus and stratocumulus. Preliminary analyses show how these data are being used to analyze cloud-aerosol relationships, determine the aerosol sizes that are responsible for nucleating cloud drops, characterize the horizontal variability of the cloud radiative impacts, and evaluate air-borne and surface-based cloud property retrievals. We discuss how conducting an extended-term campaign requires a simplified operating paradigm that is different from that used for typical, short-term, intensive aircraft field programs.

  6. Applications of large-eddy simulation: Synthesis of neutral boundary layer models

    SciTech Connect (OSTI)

    Ohmstede, W.D.

    1987-12-01

    The object of this report is to describe progress made towards the application of large-eddy simulation (LES), in particular, to the study of the neutral boundary layer (NBL). The broad purpose of the study is to provide support to the LES project currently underway at LLNL. The specific purpose of this study is to lay the groundwork for the simulation of the SBL through the establishment and implementation of model criteria for the simulation of the NBL. The idealistic NBL is never observed in the atmosphere and therefore has little practical significance. However, it is of considerable theoretical interest for several reasons. The report discusses the concept of Rossby-number similarity theory as it applies to the NBL. A particular implementation of the concept is described. Then, the results from prior simulations of the NBL are summarized. Model design criteria for two versions of the Brost LES (BLES) model are discussed. The general guidelines for the development of Version 1 of the Brost model (BV1) were to implement the model with a minimum of modifications which would alter the design criteria as established by Brost. Two major modifications of BLES incorporated into BV1 pertain to the initialization/parameterization of the model and the generalization of the boundary conditions at the air/earth interface. 18 refs., 4 figs.

  7. RACORO continental boundary layer cloud investigations. 2. Large-eddy simulations of cumulus clouds and evaluation with in-situ and ground-based observations

    SciTech Connect (OSTI)

    Endo, Satoshi; Fridlind, Ann M.; Lin, Wuyin; Vogelmann, Andrew M.; Toto, Tami; Ackerman, Andrew S.; McFarquhar, Greg M.; Jackson, Robert C.; Jonsson, Haflidi H.; Liu, Yangang

    2015-06-19

    A 60-hour case study of continental boundary layer cumulus clouds is examined using two large-eddy simulation (LES) models. The case is based on observations obtained during the RACORO Campaign (Routine Atmospheric Radiation Measurement [ARM] Aerial Facility [AAF] Clouds with Low Optical Water Depths [CLOWD] Optical Radiative Observations) at the ARM Climate Research Facility's Southern Great Plains site. The LES models are driven by continuous large-scale and surface forcings, and are constrained by multi-modal and temporally varying aerosol number size distribution profiles derived from aircraft observations. We compare simulated cloud macrophysical and microphysical properties with ground-based remote sensing and aircraft observations. The LES simulations capture the observed transitions of the evolving cumulus-topped boundary layers during the three daytime periods, and generally reproduce variations of droplet number concentration with liquid water content (LWC), corresponding to the gradient between the cloud centers and cloud edges at given heights. The observed LWC values fall within the range of simulated values; the observed droplet number concentrations are commonly higher than simulated, but differences remain on par with potential estimation errors in the aircraft measurements. Sensitivity studies examine the influences of bin microphysics versus bulk microphysics, aerosol advection, supersaturation treatment, and aerosol hygroscopicity. Simulated macrophysical cloud properties are found to be insensitive in this non-precipitating case, but microphysical properties are especially sensitive to bulk microphysics supersaturation treatment and aerosol hygroscopicity.

  8. RACORO continental boundary layer cloud investigations. 2. Large-eddy simulations of cumulus clouds and evaluation with in-situ and ground-based observations

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

    Endo, Satoshi; Fridlind, Ann M.; Lin, Wuyin; Vogelmann, Andrew M.; Toto, Tami; Ackerman, Andrew S.; McFarquhar, Greg M.; Jackson, Robert C.; Jonsson, Haflidi H.; Liu, Yangang

    2015-06-19

    A 60-hour case study of continental boundary layer cumulus clouds is examined using two large-eddy simulation (LES) models. The case is based on observations obtained during the RACORO Campaign (Routine Atmospheric Radiation Measurement [ARM] Aerial Facility [AAF] Clouds with Low Optical Water Depths [CLOWD] Optical Radiative Observations) at the ARM Climate Research Facility's Southern Great Plains site. The LES models are driven by continuous large-scale and surface forcings, and are constrained by multi-modal and temporally varying aerosol number size distribution profiles derived from aircraft observations. We compare simulated cloud macrophysical and microphysical properties with ground-based remote sensing and aircraft observations.more » The LES simulations capture the observed transitions of the evolving cumulus-topped boundary layers during the three daytime periods, and generally reproduce variations of droplet number concentration with liquid water content (LWC), corresponding to the gradient between the cloud centers and cloud edges at given heights. The observed LWC values fall within the range of simulated values; the observed droplet number concentrations are commonly higher than simulated, but differences remain on par with potential estimation errors in the aircraft measurements. Sensitivity studies examine the influences of bin microphysics versus bulk microphysics, aerosol advection, supersaturation treatment, and aerosol hygroscopicity. Simulated macrophysical cloud properties are found to be insensitive in this non-precipitating case, but microphysical properties are especially sensitive to bulk microphysics supersaturation treatment and aerosol hygroscopicity.« less

  9. Nitrogen Oxides in the Nocturnal Boundary Layer: Chemistry of Nitrous Acid (HONO) and the Nitrate Radical (N03)

    SciTech Connect (OSTI)

    Jochen Stutz

    2005-05-24

    Summary Chemical processes occurring at night in the lowest part of the urban atmosphere, the so called nocturnal boundary layer (NBL), can influence the composition of the atmosphere during the night as well as the following day. They may impact the budgets of some of the most important pollutants, such as ozone and nitrogen oxides, as well as influence size and composition of particular matter. Few studies have thus far concentrated on the nocturnal chemistry of the urban NBL, most likely due to the strong influence of vertical transport and mixing, which requires the measurement of trace gas profiles instead of simple point observations. Motivated by our lack of observations and understanding of nocturnal chemistry, the focus of this project was the study of the vertical distribution of trace gases and the altitude dependence of nocturnal chemistry under polluted conditions through field observations and modeling studies. The analysis of three field experiments (TEXAQS, Houston, 2000; Phoenix Sunrise Ozone Experiment, 2001; NAPOX, Boston, 2002), two of which were performed in this project, showed that ozone concentrations typically increase with height in the lowest 150m, while NO2 typically decreases. NO3, the dominant nocturnal radical species, showed much higher concentrations in the upper part of the NBL, and was often not present at the ground. With the help of a one-dimensional chemical transport model, developed in this project, we found that the interaction of ground emissions of NOx and hydrocarbons, together with their vertical transport, is responsible for the vertical profiles. The dominant chemical reactions influencing ozone, NO2 and NO3 are the reaction of ozone and NO3 with freshly emitted NO. Sensitivity studies with our model showed that the magnitude of the trace gas gradients depend both on the emission rates and the vertical stability of the NBL. Observations and model analysis clearly show that nocturnal chemistry in urban areas is altitude

  10. Estimations of atmospheric boundary layer fluxes and other turbulence parameters from Doppler lidar data

    SciTech Connect (OSTI)

    Tzvi Galchen; Mei Xu ); Eberhard, W.L. )

    1992-11-30

    This work is part of the First International Satellite Land Surface Climatology Project (ISLSCP) Field Experiment (FIFE), an international land-surface-atmosphere experiment aimed at improving the way climate models represent energy, water, heat, and carbon exchanges, and improving the utilization of satellite based remote sensing to monitor such parameters. Here the authors present results on doppler LIDAR measurements used to measure a range of turbulence parameters in the region of the unstable planetary boundary layer (PBL). The parameters include, averaged velocities, cartesian velocities, variances in velocities, parts of the covariance associated with vertical fluxes of horizontal momentum, and third moments of the vertical velocity. They explain their analysis technique, especially as it relates to error reduction of the averaged turbulence parameters from individual measurements with relatively large errors. The scales studied range from 150m to 12km. With this new diagnostic they address questions about the behavior of the convectively unstable PBL, as well as the stable layer which overlies it.

  11. ARM - PI Product - Raman lidar/AERI PBL Height Product

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

    ProductsRaman lidar/AERI PBL Height Product 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 : Raman lidar/AERI PBL Height Product Planetary Boundary Layer (PBL) heights have been computed using potential temperature profiles derived from Raman lidar and AERI measurements. Raman lidar measurements of the rotational Raman scattering from nitrogen and oxygen are used to derive vertical profiles of potential

  12. On the Interaction between Marine Boundary Layer Cellular Cloudiness and Surface Heat Fluxes

    SciTech Connect (OSTI)

    Kazil, J.; Feingold, G.; Wang, Hailong; Yamaguchi, T.

    2014-01-02

    The interaction between marine boundary layer cellular cloudiness and surface uxes of sensible and latent heat is investigated. The investigation focuses on the non-precipitating closed-cell state and the precipitating open-cell state at low geostrophic wind speed. The Advanced Research WRF model is used to conduct cloud-system-resolving simulations with interactive surface fluxes of sensible heat, latent heat, and of sea salt aerosol, and with a detailed representation of the interaction between aerosol particles and clouds. The mechanisms responsible for the temporal evolution and spatial distribution of the surface heat fluxes in the closed- and open-cell state are investigated and explained. It is found that the horizontal spatial structure of the closed-cell state determines, by entrainment of dry free tropospheric air, the spatial distribution of surface air temperature and water vapor, and, to a lesser degree, of the surface sensible and latent heat flux. The synchronized dynamics of the the open-cell state drives oscillations in surface air temperature, water vapor, and in the surface fluxes of sensible and latent heat, and of sea salt aerosol. Open-cell cloud formation, cloud optical depth and liquid water path, and cloud and rain water path are identified as good predictors of the spatial distribution of surface air temperature and sensible heat flux, but not of surface water vapor and latent heat flux. It is shown that by enhancing the surface sensible heat flux, the open-cell state creates conditions by which it is maintained. While the open-cell state under consideration is not depleted in aerosol, and is insensitive to variations in sea-salt fluxes, it also enhances the sea-salt flux relative to the closed-cell state. In aerosol-depleted conditions, this enhancement may replenish the aerosol needed for cloud formation, and hence contribute to the perpetuation of the open-cell state as well. Spatial homogenization of the surface fluxes is found to have

  13. Investigation of Rossby-number similarity in the neutral boundary layer using large-eddy simulation

    SciTech Connect (OSTI)

    Ohmstede, W.D.; Cederwall, R.T.; Meyers, R.E.

    1988-01-01

    One special case of particular interest, especially to theoreticians, is the steady-state, horizontally homogeneous, autobarotropic (PLB), hereafter referred to as the neutral boundary layer (NBL). The NBL is in fact a 'rare' atmospheric phenomenon, generally associated with high-wind situations. Nevertheless, there is a disproportionate interest in this problem because Rossby-number similarity theory provides a sound approach for addressing this issue. Rossby-number similarity theory has rather wide acceptance, but because of the rarity of the 'true' NBL state, there remains an inadequate experimental database for quantifying constants associated with the Rossby-number similarity concept. Although it remains a controversial issue, it has been proposed that large-eddy simulation (LES) is an alternative to physical experimentation for obtaining basic atmospherc 'data'. The objective of the study reported here is to investigate Rossby-number similarity in the NBL using LES. Previous studies have not addressed Rossby-number similarity explicitly, although they made use of it in the interpretation of their results. The intent is to calculate several sets of NBL solutions that are ambiguous relative to the their respective Rossby numbers and compare the results for similarity, or the lack of it. 14 refs., 1 fig.

  14. Clouds, Aerosol, and Precipitation in the Marine Boundary Layer (CAP-MBL) Final Campaign Report

    SciTech Connect (OSTI)

    Wood, R.

    2016-01-01

    The extensive coverage of low clouds over the subtropical eastern oceans greatly impacts the current climate. In addition, the response of low clouds to changes in atmospheric greenhouse gases and aerosols is a major source of uncertainty, which thwarts accurate prediction of future climate change. Low clouds are poorly simulated in climate models, partly due to inadequate long-term simultaneous observations of their macrophysical and microphysical structure, radiative effects, and associated aerosol distribution in regions where their impact is greatest. The thickness and extent of subtropical low clouds is dependent on tight couplings between surface fluxes of heat and moisture, radiative cooling, boundary layer turbulence, and precipitation (much of which evaporates before reaching the ocean surface and is closely connected to the abundance of cloud condensation nuclei). These couplings have been documented as a result of past field programs and model studies. However, extensive research is still required to achieve a quantitative understanding sufficient for developing parameterizations, which adequately predict aerosol indirect effects and low cloud response to climate perturbations. This is especially true of the interactions between clouds, aerosol, and precipitation. These processes take place in an ever-changing synoptic environment that can confound interpretation of short time period observations.

  15. A method for the direct numerical simulation of hypersonic boundary-layer instability with finite-rate chemistry

    SciTech Connect (OSTI)

    Marxen, Olaf, E-mail: olaf.marxen@vki.ac.be [Center for Turbulence Research, Building 500, Stanford University, Stanford, CA 94305-3035 (United States) [Center for Turbulence Research, Building 500, Stanford University, Stanford, CA 94305-3035 (United States); Aeronautics and Aerospace Department, von Karman Institute for Fluid Dynamics, Chausse de Waterloo, 72, 1640 Rhode-St-Gense (Belgium); Magin, Thierry E. [Aeronautics and Aerospace Department, von Karman Institute for Fluid Dynamics, Chausse de Waterloo, 72, 1640 Rhode-St-Gense (Belgium)] [Aeronautics and Aerospace Department, von Karman Institute for Fluid Dynamics, Chausse de Waterloo, 72, 1640 Rhode-St-Gense (Belgium); Shaqfeh, Eric S.G.; Iaccarino, Gianluca [Center for Turbulence Research, Building 500, Stanford University, Stanford, CA 94305-3035 (United States)] [Center for Turbulence Research, Building 500, Stanford University, Stanford, CA 94305-3035 (United States)

    2013-12-15

    A new numerical method is presented here that allows to consider chemically reacting gases during the direct numerical simulation of a hypersonic fluid flow. The method comprises the direct coupling of a solver for the fluid mechanical model and a library providing the physio-chemical model. The numerical method for the fluid mechanical model integrates the compressible NavierStokes equations using an explicit time advancement scheme and high-order finite differences. This NavierStokes code can be applied to the investigation of laminar-turbulent transition and boundary-layer instability. The numerical method for the physio-chemical model provides thermodynamic and transport properties for different gases as well as chemical production rates, while here we exclusively consider a five species air mixture. The new method is verified for a number of test cases at Mach 10, including the one-dimensional high-temperature flow downstream of a normal shock, a hypersonic chemical reacting boundary layer in local thermodynamic equilibrium and a hypersonic reacting boundary layer with finite-rate chemistry. We are able to confirm that the diffusion flux plays an important role for a high-temperature boundary layer in local thermodynamic equilibrium. Moreover, we demonstrate that the flow for a case previously considered as a benchmark for the investigation of non-equilibrium chemistry can be regarded as frozen. Finally, the new method is applied to investigate the effect of finite-rate chemistry on boundary layer instability by considering the downstream evolution of a small-amplitude wave and comparing results with those obtained for a frozen gas as well as a gas in local thermodynamic equilibrium.

  16. Clouds, Precipitation, and Marine Boundary Layer Structure during the MAGIC Field Campaign

    SciTech Connect (OSTI)

    Zhou, Xiaoli; Kollias, Pavlos; Lewis, Ernie R.

    2015-03-01

    The recent ship-based MAGIC (Marine ARM GCSS Pacific Cross-Section Intercomparison (GPCI) Investigation of Clouds) field campaign with the marine-capable Second ARM Mobile Facility (AMF2) deployed on the Horizon Lines cargo container M/V Spirit provided nearly 200 days of intraseasonal high-resolution observations of clouds, precipitation, and marine boundary layer (MBL) structure on multiple legs between Los Angeles, California, and Honolulu, Hawaii. During the deployment, MBL clouds exhibited a much higher frequency of occurrence than other cloud types and occurred more often in the warm season than in the cold season. MBL clouds demonstrated a propensity to produce precipitation, which often evaporated before reaching the ocean surface. The formation of stratocumulus is strongly correlated to a shallow MBL with a strong inversion and a weak transition, while cumulus formation is associated with a much weaker inversion and stronger transition. The estimated inversion strength is shown to depend seasonally on the potential temperature at 700 hPa. The location of the commencement of systematic MBL decoupling always occurred eastward of the locations of cloud breakup, and the systematic decoupling showed a strong moisture stratification. The entrainment of the dry warm air above the inversion appears to be the dominant factor triggering the systematic decoupling, while surface latent heat flux, precipitation, and diurnal circulation did not play major roles. MBL clouds broke up over a short spatial region due to the changes in the synoptic conditions, implying that in real atmospheric conditions the MBL clouds do not have enough time to evolve as in the idealized models. (auth)

  17. Turbulent kinetics of a large wind farm and their impact in the neutral boundary layer

    SciTech Connect (OSTI)

    Na, Ji Sung; Koo, Eunmo; Munoz-Esparza, Domingo; Jin, Emilia Kyung; Linn, Rodman; Lee, Joon Sang

    2015-12-28

    High-resolution large-eddy simulation of the flow over a large wind farm (64 wind turbines) is performed using the HIGRAD/FIRETEC-WindBlade model, which is a high-performance computing wind turbine–atmosphere interaction model that uses the Lagrangian actuator line method to represent rotating turbine blades. These high-resolution large-eddy simulation results are used to parameterize the thrust and power coefficients that contain information about turbine interference effects within the wind farm. Those coefficients are then incorporated into the WRF (Weather Research and Forecasting) model in order to evaluate interference effects in larger-scale models. In the high-resolution WindBlade wind farm simulation, insufficient distance between turbines creates the interference between turbines, including significant vertical variations in momentum and turbulent intensity. The characteristics of the wake are further investigated by analyzing the distribution of the vorticity and turbulent intensity. Quadrant analysis in the turbine and post-turbine areas reveals that the ejection motion induced by the presence of the wind turbines is dominant compared to that in the other quadrants, indicating that the sweep motion is increased at the location where strong wake recovery occurs. Regional-scale WRF simulations reveal that although the turbulent mixing induced by the wind farm is partly diffused to the upper region, there is no significant change in the boundary layer depth. The velocity deficit does not appear to be very sensitive to the local distribution of turbine coefficients. However, differences of about 5% on parameterized turbulent kinetic energy were found depending on the turbine coefficient distribution. Furthermore, turbine coefficients that consider interference in the wind farm should be used in wind farm parameterization for larger-scale models to better describe sub-grid scale turbulent processes.

  18. Clouds, Precipitation, and Marine Boundary Layer Structure during the MAGIC Field Campaign

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

    Zhou, Xiaoli; Kollias, Pavlos; Lewis, Ernie R.

    2015-03-01

    The recent ship-based MAGIC (Marine ARM GCSS Pacific Cross-Section Intercomparison (GPCI) Investigation of Clouds) field campaign with the marine-capable Second ARM Mobile Facility (AMF2) deployed on the Horizon Lines cargo container M/V Spirit provided nearly 200 days of intraseasonal high-resolution observations of clouds, precipitation, and marine boundary layer (MBL) structure on multiple legs between Los Angeles, California, and Honolulu, Hawaii. During the deployment, MBL clouds exhibited a much higher frequency of occurrence than other cloud types and occurred more often in the warm season than in the cold season. MBL clouds demonstrated a propensity to produce precipitation, which often evaporatedmore » before reaching the ocean surface. The formation of stratocumulus is strongly correlated to a shallow MBL with a strong inversion and a weak transition, while cumulus formation is associated with a much weaker inversion and stronger transition. The estimated inversion strength is shown to depend seasonally on the potential temperature at 700 hPa. The location of the commencement of systematic MBL decoupling always occurred eastward of the locations of cloud breakup, and the systematic decoupling showed a strong moisture stratification. The entrainment of the dry warm air above the inversion appears to be the dominant factor triggering the systematic decoupling, while surface latent heat flux, precipitation, and diurnal circulation did not play major roles. MBL clouds broke up over a short spatial region due to the changes in the synoptic conditions, implying that in real atmospheric conditions the MBL clouds do not have enough time to evolve as in the idealized models. (auth)« less

  19. Turbulent kinetics of a large wind farm and their impact in the neutral boundary layer

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

    Na, Ji Sung; Koo, Eunmo; Munoz-Esparza, Domingo; Jin, Emilia Kyung; Linn, Rodman; Lee, Joon Sang

    2015-12-28

    High-resolution large-eddy simulation of the flow over a large wind farm (64 wind turbines) is performed using the HIGRAD/FIRETEC-WindBlade model, which is a high-performance computing wind turbine–atmosphere interaction model that uses the Lagrangian actuator line method to represent rotating turbine blades. These high-resolution large-eddy simulation results are used to parameterize the thrust and power coefficients that contain information about turbine interference effects within the wind farm. Those coefficients are then incorporated into the WRF (Weather Research and Forecasting) model in order to evaluate interference effects in larger-scale models. In the high-resolution WindBlade wind farm simulation, insufficient distance between turbines createsmore » the interference between turbines, including significant vertical variations in momentum and turbulent intensity. The characteristics of the wake are further investigated by analyzing the distribution of the vorticity and turbulent intensity. Quadrant analysis in the turbine and post-turbine areas reveals that the ejection motion induced by the presence of the wind turbines is dominant compared to that in the other quadrants, indicating that the sweep motion is increased at the location where strong wake recovery occurs. Regional-scale WRF simulations reveal that although the turbulent mixing induced by the wind farm is partly diffused to the upper region, there is no significant change in the boundary layer depth. The velocity deficit does not appear to be very sensitive to the local distribution of turbine coefficients. However, differences of about 5% on parameterized turbulent kinetic energy were found depending on the turbine coefficient distribution. Furthermore, turbine coefficients that consider interference in the wind farm should be used in wind farm parameterization for larger-scale models to better describe sub-grid scale turbulent processes.« less

  20. Retrieval of Urban Boundary Layer Structures from Doppler Lidar Data. Part I: Accuracy Assessment

    SciTech Connect (OSTI)

    Xia, Quanxin; Lin, Ching Long; Calhoun, Ron; Newsom, Rob K.

    2008-01-01

    Two coherent Doppler lidars from the US Army Research Laboratory (ARL) and Arizona State University (ASU) were deployed in the Joint Urban 2003 atmospheric dispersion field experiment (JU2003) held in Oklahoma City. The dual lidar data are used to evaluate the accuracy of the four-dimensional variational data assimilation (4DVAR) method and identify the coherent flow structures in the urban boundary layer. The objectives of the study are three-fold. The first objective is to examine the effect of eddy viscosity models on the quality of retrieved velocity data. The second objective is to determine the fidelity of single-lidar 4DVAR and evaluate the difference between single- and dual-lidar retrievals. The third objective is to correlate the retrieved flow structures with the ground building data. It is found that the approach of treating eddy viscosity as part of control variables yields better results than the approach of prescribing viscosity. The ARL single-lidar 4DVAR is able to retrieve radial velocity fields with an accuracy of 98% in the along-beam direction and 80-90% in the cross-beam direction. For the dual-lidar 4DVAR, the accuracy of retrieved radial velocity in the ARL cross-beam direction improves to 90-94%. By using the dual-lidar retrieved data as a reference, the single-lidar 4DVAR is able to recover fluctuating velocity fields with 70-80% accuracy in the along-beam direction and 60-70% accuracy in the cross-beam direction. Large-scale convective roll structures are found in the vicinity of downtown airpark and parks. Vortical structures are identified near the business district. Strong updrafts and downdrafts are also found above a cluster of restaurants.

  1. Collaborative Research: ARM observations for the development and evaluation of models and parameterizations of cloudy boundary layers

    SciTech Connect (OSTI)

    Albrecht, Bruce,

    2013-07-12

    This is a collaborative project with Dr. Ping Zhu at Florida International University. It was designed to address key issues regarding the treatment of boundary layer cloud processes in climate models with UM’s research focusing on the analyses of ARM cloud radar observations from MMCR and WACR and FIU’s research focusing on numerical simulations of boundary layer clouds. This project capitalized on recent advancements in the ARM Millimeter Cloud Radar (MMCR) processing and the development of the WACR (at the SGP) to provide high temporal and spatial resolution Doppler cloud radar measurements for characterizing in-cloud turbulence, large-eddy circulations, and high resolution cloud structures of direct relevance to high resolution numerical modeling studies. The principal focus of the observational component of this collaborative study during this funding period was on stratocumulus clouds over the SGP site and fair-weather cumuli over the Nauru site. The statistical descriptions of the vertical velocity structures in continental stratocumulus clouds and in the Nauru shallow cumuli that are part of this study represents the most comprehensive observations of the vertical velocities in boundary layer clouds to date and were done in collaboration with Drs. Virendra Ghate and Pavlos Kollias.

  2. Vehicle cabin cooling system for capturing and exhausting heated boundary layer air from inner surfaces of solar heated windows

    DOE Patents [OSTI]

    Farrington, Robert B.; Anderson, Ren

    2001-01-01

    The cabin cooling system includes a cooling duct positioned proximate and above upper edges of one or more windows of a vehicle to exhaust hot air as the air is heated by inner surfaces of the windows and forms thin boundary layers of heated air adjacent the heated windows. The cabin cooling system includes at least one fan to draw the hot air into the cooling duct at a flow rate that captures the hot air in the boundary layer without capturing a significant portion of the cooler cabin interior air and to discharge the hot air at a point outside the vehicle cabin, such as the vehicle trunk. In a preferred embodiment, the cooling duct has a cross-sectional area that gradually increases from a distal point to a proximal point to the fan inlet to develop a substantially uniform pressure drop along the length of the cooling duct. Correspondingly, this cross-sectional configuration develops a uniform suction pressure and uniform flow rate at the upper edge of the window to capture the hot air in the boundary layer adjacent each window.

  3. Investigating the source, transport, and isotope composition of water vapor in the planetary boundary layer

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

    Griffis, Timothy J.; Wood, Jeffrey D.; Baker, John M.; Lee, Xuhui; Xiao, Ke; Chen, Zichong; Welp, Lisa R.; Schultz, Natalie M.; Gorski, Galen; Chen, Ming; et al

    2016-04-25

    Increasing atmospheric humidity and convective precipitation over land provide evidence of intensification of the hydrologic cycle – an expected response to surface warming. The extent to which terrestrial ecosystems modulate these hydrologic factors is important to understand feedbacks in the climate system. We measured the oxygen and hydrogen isotope composition of water vapor at a very tall tower (185 m) in the upper Midwest, United States, to diagnose the sources, transport, and fractionation of water vapor in the planetary boundary layer (PBL) over a 3-year period (2010 to 2012). These measurements represent the first set of annual water vapor isotopemore » observations for this region. Several simple isotope models and cross-wavelet analyses were used to assess the importance of the Rayleigh distillation process, evaporation, and PBL entrainment processes on the isotope composition of water vapor. The vapor isotope composition at this tall tower site showed a large seasonal amplitude (mean monthly δ18Ov ranged from –40.2 to –15.9 ‰ and δ2Hv ranged from –278.7 to –113.0 ‰) and followed the familiar Rayleigh distillation relation with water vapor mixing ratio when considering the entire hourly data set. However, this relation was strongly modulated by evaporation and PBL entrainment processes at timescales ranging from hours to several days. The wavelet coherence spectra indicate that the oxygen isotope ratio and the deuterium excess (dv) of water vapor are sensitive to synoptic and PBL processes. According to the phase of the coherence analyses, we show that evaporation often leads changes in dv, confirming that it is a potential tracer of regional evaporation. Isotope mixing models indicate that on average about 31 % of the growing season PBL water vapor is derived from regional evaporation. However, isoforcing calculations and mixing model analyses for high PBL water vapor mixing ratio events ( > 25 mmol mol–1) indicate that regional

  4. RACORO continental boundary layer cloud investigations. Part I: Case study development and ensemble large-scale forcings

    SciTech Connect (OSTI)

    Vogelmann, Andrew M.; Fridlind, Ann M.; Toto, Tami; Endo, Satoshi; Lin, Wuyin; Wang, Jian; Feng, Sha; Zhang, Yunyan; Turner, David D.; Liu, Yangang; Li, Zhijin; Xie, Shaocheng; Ackerman, Andrew S.; Zhang, Minghua; Khairoutdinov, Marat

    2015-06-19

    Observation-based modeling case studies of continental boundary layer clouds have been developed to study cloudy boundary layers, aerosol influences upon them, and their representation in cloud- and global-scale models. Three 60-hour case study periods span the temporal evolution of cumulus, stratiform, and drizzling boundary layer cloud systems, representing mixed and transitional states rather than idealized or canonical cases. Based on in-situ measurements from the RACORO field campaign and remote-sensing observations, the cases are designed with a modular configuration to simplify use in large-eddy simulations (LES) and single-column models. Aircraft measurements of aerosol number size distribution are fit to lognormal functions for concise representation in models. Values of the aerosol hygroscopicity parameter, ?, are derived from observations to be ~0.10, which are lower than the 0.3 typical over continents and suggestive of a large aerosol organic fraction. Ensemble large-scale forcing datasets are derived from the ARM variational analysis, ECMWF forecasts, and a multi-scale data assimilation system. The forcings are assessed through comparison of measured bulk atmospheric and cloud properties to those computed in 'trial' large-eddy simulations, where more efficient run times are enabled through modest reductions in grid resolution and domain size compared to the full-sized LES grid. Simulations capture many of the general features observed, but the state-of-the-art forcings were limited at representing details of cloud onset, and tight gradients and high-resolution transients of importance. Methods for improving the initial conditions and forcings are discussed. The cases developed are available to the general modeling community for studying continental boundary clouds.

  5. RACORO continental boundary layer cloud investigations. Part I: Case study development and ensemble large-scale forcings

    SciTech Connect (OSTI)

    Vogelmann, Andrew M.; Fridlind, Ann M.; Toto, Tami; Endo, Satoshi; Lin, Wuyin; Wang, Jian; Feng, Sha; Zhang, Yunyan; Turner, David D.; Liu, Yangang; Li, Zhijin; Xie, Shaocheng; Ackerman, Andrew S.; Zhang, Minghua; Khairoutdinov, Marat

    2015-06-19

    Observation-based modeling case studies of continental boundary layer clouds have been developed to study cloudy boundary layers, aerosol influences upon them, and their representation in cloud- and global-scale models. Three 60-hour case study periods span the temporal evolution of cumulus, stratiform, and drizzling boundary layer cloud systems, representing mixed and transitional states rather than idealized or canonical cases. Based on in-situ measurements from the RACORO field campaign and remote-sensing observations, the cases are designed with a modular configuration to simplify use in large-eddy simulations (LES) and single-column models. Aircraft measurements of aerosol number size distribution are fit to lognormal functions for concise representation in models. Values of the aerosol hygroscopicity parameter, κ, are derived from observations to be ~0.10, which are lower than the 0.3 typical over continents and suggestive of a large aerosol organic fraction. Ensemble large-scale forcing datasets are derived from the ARM variational analysis, ECMWF forecasts, and a multi-scale data assimilation system. The forcings are assessed through comparison of measured bulk atmospheric and cloud properties to those computed in 'trial' large-eddy simulations, where more efficient run times are enabled through modest reductions in grid resolution and domain size compared to the full-sized LES grid. Simulations capture many of the general features observed, but the state-of-the-art forcings were limited at representing details of cloud onset, and tight gradients and high-resolution transients of importance. Methods for improving the initial conditions and forcings are discussed. The cases developed are available to the general modeling community for studying continental boundary clouds.

  6. RACORO continental boundary layer cloud investigations. Part I: Case study development and ensemble large-scale forcings

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

    Vogelmann, Andrew M.; Fridlind, Ann M.; Toto, Tami; Endo, Satoshi; Lin, Wuyin; Wang, Jian; Feng, Sha; Zhang, Yunyan; Turner, David D.; Liu, Yangang; et al

    2015-06-19

    Observation-based modeling case studies of continental boundary layer clouds have been developed to study cloudy boundary layers, aerosol influences upon them, and their representation in cloud- and global-scale models. Three 60-hour case study periods span the temporal evolution of cumulus, stratiform, and drizzling boundary layer cloud systems, representing mixed and transitional states rather than idealized or canonical cases. Based on in-situ measurements from the RACORO field campaign and remote-sensing observations, the cases are designed with a modular configuration to simplify use in large-eddy simulations (LES) and single-column models. Aircraft measurements of aerosol number size distribution are fit to lognormal functionsmore » for concise representation in models. Values of the aerosol hygroscopicity parameter, κ, are derived from observations to be ~0.10, which are lower than the 0.3 typical over continents and suggestive of a large aerosol organic fraction. Ensemble large-scale forcing datasets are derived from the ARM variational analysis, ECMWF forecasts, and a multi-scale data assimilation system. The forcings are assessed through comparison of measured bulk atmospheric and cloud properties to those computed in 'trial' large-eddy simulations, where more efficient run times are enabled through modest reductions in grid resolution and domain size compared to the full-sized LES grid. Simulations capture many of the general features observed, but the state-of-the-art forcings were limited at representing details of cloud onset, and tight gradients and high-resolution transients of importance. Methods for improving the initial conditions and forcings are discussed. The cases developed are available to the general modeling community for studying continental boundary clouds.« less

  7. Characterization of particle cloud droplet activity and composition in the free troposphere and the boundary layer during INTEX-B

    SciTech Connect (OSTI)

    Roberts, G. C.; Day, D. A.; Russell, Lynn M.; Dunlea, E. J.; Jimenez, J. L.; Tomlinson, Jason M.; Collins, Donald R.; Shinozuka, Y.; Clarke, A. D.

    2010-07-20

    Measurements of cloud condensation nuclei (CCN), aerosol size distributions, and submicron aerosol composition were made as part of the Intercontinental Chemical Transport Experiment Phase B (INTEX-B) campaign during spring 2006. Measurements were conducted from an aircraft platform over the northeastern Pacific and western North America with a focus on how the transport and evolution of Asian pollution across the Pacific Ocean affected CCN properties. A broad range of air masses were sampled and here we focus on three distinct air mass types defined geographically: the Pacific free troposphere (FT), the marine boundary layer (MBL), and the polluted continental boundary layer in the California Central Valley (CCV). These observations add to the few observations of CCN in the FT. CCN concentrations showed a large range of concentrations between air masses, however CCN activity was similar for the MBL and CCV ({kappa} {approx} 0.2-0.25). FT air masses showed evidence of long-range transport from Asia and CCN activity was consistently higher than for the boundary layer air masses. Bulk chemical measurements predicted CCN activity reasonably well for the CCV and FT air masses. Decreasing trends in {kappa} with organic mass fraction were observed for the combination of the FT and CCV air masses and can be explained by the measured soluble inorganic chemical components. Changes in hygroscopicity associated with differences in the non-refractory organic composition were too small to be distinguished from the simultaneous changes in inorganic ion composition in the FT and MBL, although measurements for the large organic fractions (0.6-0.8) found in the CCV showed values of the organic fraction hygroscopicity consistent with other polluted regions ({kappa}{sub org} {approx} 0.1-0.2). A comparison of CCN-derived {kappa} (for particles at the critical diameter) to H-TDMA-derived {kappa} (for particles at 100 nm diameter) showed similar trends, however the CCN-derived {kappa

  8. Suppressed grain-boundary scattering in atomic layer deposited Nb:TiO{sub 2} thin films

    SciTech Connect (OSTI)

    Niemelä, Janne-Petteri; Karppinen, Maarit; Hirose, Yasushi; Hasegawa, Tetsuya; Shigematsu, Kei; Sano, Masahito

    2015-11-09

    We have fabricated high-quality thin films of the transparent conducting anatase Nb:TiO{sub 2} on glass substrates through atomic layer deposition, and a subsequent reductive heat treatment of the as-deposited amorphous films. Hall-effect measurements and Drude-fitting of the Vis-NIR spectra indicate that for lightly doped films deposited at temperatures around 170 °C, grain boundary scattering becomes negligible and the mobility is predominately limited by phonon-electron scattering inherent to the anatase lattice and by impurities. Simultaneously, such lighter doping leads to reduced plasma absorption, thereby improving material's performance as a transparent conductor.

  9. Joint retrievals of cloud and drizzle in marine boundary layer clouds using ground-based radar, lidar and zenith radiances

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

    Fielding, M. D.; Chiu, J. C.; Hogan, R. J.; Feingold, G.; Eloranta, E.; O'Connor, E. J.; Cadeddu, M. P.

    2015-02-16

    Active remote sensing of marine boundary-layer clouds is challenging as drizzle drops often dominate the observed radar reflectivity. We present a new method to simultaneously retrieve cloud and drizzle vertical profiles in drizzling boundary-layer cloud using surface-based observations of radar reflectivity, lidar attenuated backscatter, and zenith radiances. Specifically, the vertical structure of droplet size and water content of both cloud and drizzle is characterised throughout the cloud. An ensemble optimal estimation approach provides full error statistics given the uncertainty in the observations. To evaluate the new method, we first perform retrievals using synthetic measurements from large-eddy simulation snapshots of cumulusmore » under stratocumulus, where cloud water path is retrieved with an error of 31 g m−2. The method also performs well in non-drizzling clouds where no assumption of the cloud profile is required. We then apply the method to observations of marine stratocumulus obtained during the Atmospheric Radiation Measurement MAGIC deployment in the northeast Pacific. Here, retrieved cloud water path agrees well with independent 3-channel microwave radiometer retrievals, with a root mean square difference of 10–20 g m−2.« less

  10. Joint retrievals of cloud and drizzle in marine boundary layer clouds using ground-based radar, lidar and zenith radiances

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

    Fielding, M. D.; Chiu, J. C.; Hogan, R. J.; Feingold, G.; Eloranta, E.; O'Connor, E. J.; Cadeddu, M. P.

    2015-07-02

    Active remote sensing of marine boundary-layer clouds is challenging as drizzle drops often dominate the observed radar reflectivity. We present a new method to simultaneously retrieve cloud and drizzle vertical profiles in drizzling boundary-layer clouds using surface-based observations of radar reflectivity, lidar attenuated backscatter, and zenith radiances under conditions when precipitation does not reach the surface. Specifically, the vertical structure of droplet size and water content of both cloud and drizzle is characterised throughout the cloud. An ensemble optimal estimation approach provides full error statistics given the uncertainty in the observations. To evaluate the new method, we first perform retrievalsmore » using synthetic measurements from large-eddy simulation snapshots of cumulus under stratocumulus, where cloud water path is retrieved with an error of 31 g m-2. The method also performs well in non-drizzling clouds where no assumption of the cloud profile is required. We then apply the method to observations of marine stratocumulus obtained during the Atmospheric Radiation Measurement MAGIC deployment in the Northeast Pacific. Here, retrieved cloud water path agrees well with independent three-channel microwave radiometer retrievals, with a root mean square difference of 10–20 g m-2.« less

  11. Global and regional modeling of clouds and aerosols in the marine boundary layer during VOCALS: the VOCA intercomparison

    SciTech Connect (OSTI)

    Wyant, M. C.; Bretherton, Christopher S.; Wood, Robert; Carmichael, Gregory; Clarke, A. D.; Fast, Jerome D.; George, R.; Gustafson, William I.; Hannay, Cecile; Lauer, Axel; Lin, Yanluan; Morcrette, J. -J.; Mulcahay, Jane; Saide, Pablo; Spak, S. N.; Yang, Qing

    2015-01-09

    A diverse collection of models are used to simulate the marine boundary layer in the southeast Pacific region during the period of the October–November 2008 VOCALS REx (VAMOS Ocean Cloud Atmosphere Land Study Regional Experiment) field campaign. Regional models simulate the period continuously in boundary-forced free-running mode, while global forecast models and GCMs (general circulation models) are run in forecast mode. The models are compared to extensive observations along a line at 20° S extending westward from the South American coast. Most of the models simulate cloud and aerosol characteristics and gradients across the region that are recognizably similar to observations, despite the complex interaction of processes involved in the problem, many of which are parameterized or poorly resolved. Some models simulate the regional low cloud cover well, though many models underestimate MBL (marine boundary layer) depth near the coast. Most models qualitatively simulate the observed offshore gradients of SO2, sulfate aerosol, CCN (cloud condensation nuclei) concentration in the MBL as well as differences in concentration between the MBL and the free troposphere. Most models also qualitatively capture the decrease in cloud droplet number away from the coast. However, there are large quantitative intermodel differences in both means and gradients of these quantities. Many models are able to represent episodic offshore increases in cloud droplet number and aerosol concentrations associated with periods of offshore flow. Most models underestimate CCN (at 0.1% supersaturation) in the MBL and free troposphere. The GCMs also have difficulty simulating coastal gradients in CCN and cloud droplet number concentration near the coast. The overall performance of the models demonstrates their potential utility in simulating aerosol–cloud interactions in the MBL, though quantitative estimation of aerosol–cloud interactions and aerosol indirect effects of MBL

  12. Global and regional modeling of clouds and aerosols in the marine boundary layer during VOCALS: the VOCA intercomparison

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

    Wyant, M. C.; Bretherton, Christopher S.; Wood, Robert; Carmichael, Gregory; Clarke, A. D.; Fast, Jerome D.; George, R.; Gustafson, William I.; Hannay, Cecile; Lauer, Axel; et al

    2015-01-09

    A diverse collection of models are used to simulate the marine boundary layer in the southeast Pacific region during the period of the October–November 2008 VOCALS REx (VAMOS Ocean Cloud Atmosphere Land Study Regional Experiment) field campaign. Regional models simulate the period continuously in boundary-forced free-running mode, while global forecast models and GCMs (general circulation models) are run in forecast mode. The models are compared to extensive observations along a line at 20° S extending westward from the South American coast. Most of the models simulate cloud and aerosol characteristics and gradients across the region that are recognizably similar tomore » observations, despite the complex interaction of processes involved in the problem, many of which are parameterized or poorly resolved. Some models simulate the regional low cloud cover well, though many models underestimate MBL (marine boundary layer) depth near the coast. Most models qualitatively simulate the observed offshore gradients of SO2, sulfate aerosol, CCN (cloud condensation nuclei) concentration in the MBL as well as differences in concentration between the MBL and the free troposphere. Most models also qualitatively capture the decrease in cloud droplet number away from the coast. However, there are large quantitative intermodel differences in both means and gradients of these quantities. Many models are able to represent episodic offshore increases in cloud droplet number and aerosol concentrations associated with periods of offshore flow. Most models underestimate CCN (at 0.1% supersaturation) in the MBL and free troposphere. The GCMs also have difficulty simulating coastal gradients in CCN and cloud droplet number concentration near the coast. The overall performance of the models demonstrates their potential utility in simulating aerosol–cloud interactions in the MBL, though quantitative estimation of aerosol–cloud interactions and aerosol indirect effects of MBL clouds

  13. Near-surface Density Currents Observed in the Southeast Pacific Stratocumulus-topped Marine Boundary Layer

    SciTech Connect (OSTI)

    Wilbanks, Matt C.; Yuter, S. E.; de Szoeke, S.; Brewer, W. A.; Miller, Matthew A.; Hall, Andrew M.; Burleyson, Casey D.

    2015-09-01

    Density currents (i.e. cold pools or outflows) beneath marine stratocumulus clouds are characterized using a 30-d data set of ship-based observations obtained during the 2008 Variability of American Monsoon Systems (VAMOS) Ocean-Cloud-Atmosphere-Land Study Regional Experiment (VOCALS-REx) in the southeast Pacific. An objective method identifies 71 density current fronts using an air density criterion and isolates each density current’s core (peak density) and tail (dissipating) zone. Compared to front and core zones, most density current tails exhibited weaker density gradients and wind anomalies elongated about the axis of the mean wind. The mean cloud-level advection relative to the surface layer wind (1.9 m s-1) nearly matches the mean density current propagation speed (1.8 m s-1). The similarity in speeds allows drizzle cells to deposit tails in their wakes. Based on high-resolution scanning Doppler lidar data, prefrontal updrafts had a mean intensity of 0.91 m s-1, reached an average altitude of 800 m, and were often surmounted by low-lying shelf clouds not connected to the overlying stratocumulus cloud. Nearly 90% of density currents were identified when C-band radar estimated 30-km diameter areal average rain rates exceeded 1 mm d-1. Rather than peaking when rain rates are highest overnight, density current occurrence peaks between 0600 and 0800 local solar time when enhanced local drizzle co-occurs with shallow subcloud dry and stable layers. The dry layers may contribute to density current formation by enhancing subcloud evaporation of drizzle. Density currents preferentially occur in regions of open cells but also occur in regions of closed cells.

  14. 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.

  15. TRANSPORT OF HEAT, WATER VAPOR AND CARBON DOXIDE BY LONG PERIOD EDDIES IN THE STABLE BOUNDARY LAYER

    SciTech Connect (OSTI)

    Kurzeja, R.

    2010-07-26

    The vertical transport of heat and trace chemicals for a night in April has been studied with a wavelet analysis and conventional one-hour averages. It was found that for the night of April 20, 2009, turbulent kinetic energy, heat and trace chemicals were transported directed downward from the jet core. The most significant periods for this transport were less than 5 minutes and greater than one hour with intermittent transport taking place in the 5 min to 1 hour time frame. The nocturnal boundary layer is characterized by turbulent intermittency, long period oscillations, and a slow approach to equilibrium, (Mahrt, 1999). Although turbulence is usually maintained by surface friction, downward transport from low-level jets can also play an important role in turbulence maintenance and in the transport of scalars, Mahrt (1999), Banta et al. (2006). The eddy covariance flux measurement technique assumes continuous turbulence which is unusual in the stable boundary because significant flux transport occurs via turbulent eddies whose periods are long compared with the averaging time (Goulden et al., 1996). Systematic error in eddy flux measurements is attributed mainly to the neglect of long period eddies. Banta et al. (2006) noted that observations of turbulence below the low level jet suggested that while upward transport of turbulence kinetic energy (TKE) is common, downward transport from the jet can also occur. They found that in the CASES 99 experiments that turbulence scaled well with the strength of the low-level jet, and that surface cooling was more important than surface roughness. Because nocturnal turbulence is intermittent and non-stationary, the appropriate averaging time for calculation of TKE and EC fluxes is not obvious. Wavelet analysis is, thus, a more suitable analysis tool than conventional Fourier analysis.

  16. RACORO continental boundary layer cloud investigations. 3. Separation of parameterization biases in single-column model CAM5 simulations of shallow cumulus

    SciTech Connect (OSTI)

    Lin, Wuyin; Liu, Yangang; Vogelmann, Andrew M.; Fridlind, Ann; Endo, Satoshi; Song, Hua; Feng, Sha; Toto, Tami; Li, Zhijin; Zhang, Minghua

    2015-06-19

    Climatically important low-level clouds are commonly misrepresented in climate models. The FAst-physics System TEstbed and Research (FASTER) project has constructed case studies from the Atmospheric Radiation Measurement (ARM) Climate Research Facility's Southern Great Plain site during the RACORO aircraft campaign to facilitate research on model representation of boundary-layer clouds. This paper focuses on using the single-column Community Atmosphere Model version 5 (SCAM5) simulations of a multi-day continental shallow cumulus case to identify specific parameterization causes of low-cloud biases. Consistent model biases among the simulations driven by a set of alternative forcings suggest that uncertainty in the forcing plays only a relatively minor role. In-depth analysis reveals that the model's shallow cumulus convection scheme tends to significantly under-produce clouds during the times when shallow cumuli exist in the observations, while the deep convective and stratiform cloud schemes significantly over-produce low-level clouds throughout the day. The links between model biases and the underlying assumptions of the shallow cumulus scheme are further diagnosed with the aid of large-eddy simulations and aircraft measurements, and by suppressing the triggering of the deep convection scheme. It is found that the weak boundary layer turbulence simulated is directly responsible for the weak cumulus activity and the simulated boundary layer stratiform clouds. Increased vertical and temporal resolutions are shown to lead to stronger boundary layer turbulence and reduction of low-cloud biases.

  17. RACORO continental boundary layer cloud investigations. 3. Separation of parameterization biases in single-column model CAM5 simulations of shallow cumulus

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

    Lin, Wuyin; Liu, Yangang; Vogelmann, Andrew M.; Fridlind, Ann; Endo, Satoshi; Song, Hua; Feng, Sha; Toto, Tami; Li, Zhijin; Zhang, Minghua

    2015-06-19

    Climatically important low-level clouds are commonly misrepresented in climate models. The FAst-physics System TEstbed and Research (FASTER) project has constructed case studies from the Atmospheric Radiation Measurement (ARM) Climate Research Facility's Southern Great Plain site during the RACORO aircraft campaign to facilitate research on model representation of boundary-layer clouds. This paper focuses on using the single-column Community Atmosphere Model version 5 (SCAM5) simulations of a multi-day continental shallow cumulus case to identify specific parameterization causes of low-cloud biases. Consistent model biases among the simulations driven by a set of alternative forcings suggest that uncertainty in the forcing plays only amore » relatively minor role. In-depth analysis reveals that the model's shallow cumulus convection scheme tends to significantly under-produce clouds during the times when shallow cumuli exist in the observations, while the deep convective and stratiform cloud schemes significantly over-produce low-level clouds throughout the day. The links between model biases and the underlying assumptions of the shallow cumulus scheme are further diagnosed with the aid of large-eddy simulations and aircraft measurements, and by suppressing the triggering of the deep convection scheme. It is found that the weak boundary layer turbulence simulated is directly responsible for the weak cumulus activity and the simulated boundary layer stratiform clouds. Increased vertical and temporal resolutions are shown to lead to stronger boundary layer turbulence and reduction of low-cloud biases.« less

  18. Clouds, Aerosol, and Precipitation in the Marine Boundary Layer: Analysis of Results from the ARM Mobile Facility Deployment to the Azores (2009/2010)

    SciTech Connect (OSTI)

    Wood, Robert

    2013-05-31

    The project focuses upon dataset analysis and synthesis of datasets from the AMF deployment entitled “Clouds, Aerosols, and Precipitation in the Marine Boundary Layer (CAP‐MBL)” at Graciosa Island in the Azores. Wood is serving a PI for this AMF deployment.

  19. Horizontal-Velocity and Variance Measurements in the Stable Boundary Layer Using Doppler Lidar: Sensitivity to Averaging Procedures

    SciTech Connect (OSTI)

    Pichugina, Yelena L.; Banta, Robert M.; Kelley, Neil D.; Jonkman, Bonnie J.; Tucker, Sara C.; Newsom, Rob K.; Brewer, W. A.

    2008-08-01

    Quantitative data on turbulence variables aloft--above the region of the atmosphere conveniently measured from towers--has been an important but difficult measurement need for advancing understanding and modeling of the stable boundary layer (SBL). Vertical profiles of streamwise velocity variances obtained from NOAAs High Resolution Doppler Lidar (HRDL), which have been shown to be numerically equivalent to turbulence kinetic energy (TKE) for stable conditions, are a measure of the turbulence in the SBL. In the present study, the mean horizontal wind component U and variance ?u2 were computed from HRDL measurements of the line-of-sight (LOS) velocity using a technique described in Banta, et al. (2002). The technique was tested on datasets obtained during the Lamar Low-Level Jet Project (LLLJP) carried out in early September 2003, near the town of Lamar in southeastern Colorado. This paper compares U with mean wind speed obtained from sodar and sonic anemometer measurements. It then describes several series of averaging tests that produced the best correlation between TKE calculated from sonic anemometer data at several tower levels and lidar measurements of horizontal velocity variance ?u2. The results show high correlation (0.71-0.97) of the mean U and average wind speed measured by sodar and in-situ instruments, independent of sampling strategies and averaging procedures. Comparison of estimates of variance, on the other hand, proved sensitive to both the spatial and temporal averaging techniques.

  20. Ellipsometry characterization of polycrystalline ZnO layers with the modeling of carrier concentration gradient: Effects of grain boundary, humidity, and surface texture

    SciTech Connect (OSTI)

    Sago, Keisuke; Fujiwara, Hiroyuki; Kuramochi, Hideto; Iigusa, Hitoshi; Utsumi, Kentaro

    2014-04-07

    Spectroscopic ellipsometry (SE) has been applied to study the effects of grain boundary, humidity, and surface texture on the carrier transport properties of Al-doped ZnO layers fabricated by dc and rf magnetron sputtering. In the SE analysis, the variation in the free carrier absorption toward the growth direction, induced by the ZnO grain growth on foreign substrates, has been modeled explicitly by adopting a multilayer model in which the optical carrier concentration (N{sub opt}) varies continuously with a constant optical mobility (?{sub opt}). The effect of the grain boundary has been studied by comparing ?{sub opt} with Hall mobility (?{sub Hall}). The change in ?{sub Hall}/?{sub opt} indicates a sharp structural transition of the ZnO polycrystalline layer at a thickness of d???500?nm, which correlates very well with the structure confirmed by transmission electron microscopy. In particular, below the transition thickness, the formation of the high density grain boundary leads to the reduction in the ?{sub Hall}/?{sub opt} ratio as well as N{sub opt}. As a result, we find that the thickness dependence of the carrier transport properties is almost completely governed by the grain boundary formation. On the other hand, when the ZnO layer is exposed to wet air at 85?C, ?{sub Hall} reduces drastically with a minor variation of ?{sub opt} due to the enhanced grain boundary scattering. We have also characterized textured ZnO:Al layers prepared by HCl wet etching by SE. The analysis revealed that the near-surface carrier concentration increases slightly after the etching. We demonstrate that the SE technique can be applied to distinguish various rough textured structures (size???1??m) of the ZnO layers prepared by the HCl etching.

  1. Boundary Layer Lubrication

    Broader source: Energy.gov [DOE]

    2009 DOE Hydrogen Program and Vehicle Technologies Program Annual Merit Review and Peer Evaluation Meeting, May 18-22, 2009 -- Washington D.C.

  2. Boundary Layer Lubrication Mechanisms

    Broader source: Energy.gov [DOE]

    2011 DOE Hydrogen and Fuel Cells Program, and Vehicle Technologies Program Annual Merit Review and Peer Evaluation

  3. Boundary Layer Lubrication Mechanisms

    Broader source: Energy.gov [DOE]

    2010 DOE Vehicle Technologies and Hydrogen Programs Annual Merit Review and Peer Evaluation Meeting, June 7-11, 2010 -- Washington D.C.

  4. Effect of radiation and magnetohydrodynamic free convection boundary layer flow on a solid sphere with Newtonian heating in a micropolar fluid

    SciTech Connect (OSTI)

    Alkasasbeh, Hamzeh Taha Sarif, Norhafizah Md Salleh, Mohd Zuki; Tahar, Razman Mat; Nazar, Roslinda; Pop, Ioan

    2015-02-03

    In this paper, the effect of radiation on magnetohydrodynamic free convection boundary layer flow on a solid sphere with Newtonian heating in a micropolar fluid, in which the heat transfer from the surface is proportional to the local surface temperature, is considered. The transformed boundary layer equations in the form of nonlinear partial differential equations are solved numerically using an implicit finite difference scheme known as the Keller-box method. Numerical solutions are obtained for the local wall temperature and the local skin friction coefficient, as well as the velocity, angular velocity and temperature profiles. The features of the flow and heat transfer characteristics for various values of the Prandtl number Pr, micropolar parameter K, magnetic parameter M, radiation parameter N{sub R}, the conjugate parameter γ and the coordinate running along the surface of the sphere, x are analyzed and discussed.

  5. Measurement of Boundary-Layer Temperature Profiles by a Scanning 5-MM Radiometer During the 1999 Winter NSA/AAO Radiometer Exp

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

    Boundary-Layer Temperature Profiles by a Scanning 5-MM Radiometer During the 1999 Winter NSA/AAO Radiometer Experiment and WVIOP 2000 V. Y. Leuski and E. R. Westwater Cooperative Institute for Research in the Environmental Sciences National Oceanic and Atmospheric Administration Environmental Technology Laboratory University of Colorado Boulder, Colorado Introduction A scanning 5-mm-wavelength radiometer was deployed during two Intensive Operational Periods (IOPs) at the Atmospheric Radiation

  6. Clouds, Aerosols and Precipitation in the Marine Boundary Layer (CAP-MBL) AMF Deployment Graciosa Island, Azores, NE Atlantic Ocean May 2009-December 2010

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

    the Marine Boundary Layer (CAP-MBL) Graciosa Island, Azores, NE Atlantic Ocean May 2009-December 2010 Rob Wood, University of Washington CAP-MBL Proposal Team AMF Deployment Team Thanks to Mark Miller: AMF Site Scientist Kim Nitschke: AMF Site Manager Importance of Low-Clouds for Climate Imperative that we understand the processes controlling the formation, maintenance and dissipation of low clouds in order to improve their representation in climate models. Which clouds matter for climate

  7. XMM-NEWTON OBSERVATIONS OF THE DWARF NOVA RU Peg IN QUIESCENCE: PROBE OF THE BOUNDARY LAYER

    SciTech Connect (OSTI)

    Balman, Soelen; Godon, Patrick; Sion, Edward M.; Ness, Jan-Uwe; Schlegel, Eric; Barrett, Paul E.; Szkody, Paula E-mail: patrick.godon@villanova.edu E-mail: juness@sciops.esa.int E-mail: barrett.paul@usno.navy.mil

    2011-11-10

    We present an analysis of X-ray and UV data obtained with the XMM-Newton Observatory of the long-period dwarf nova RU Peg. RU Peg contains a massive white dwarf (WD), possibly the hottest WD in a dwarf nova (DN), it has a low inclination, thus optimally exposing its X-ray emitting boundary layer (BL), and has an excellent trigonometric parallax distance. We modeled the X-ray data using XSPEC assuming a multi-temperature plasma emission model built from the MEKAL code (i.e., CEVMKL). We obtained a maximum temperature of 31.7 keV, based on the European Photon Imaging Camera MOS1, 2 and pn data, indicating that RU Peg has an X-ray spectrum harder than most DNe, except U Gem. This result is consistent with and indirectly confirms the large mass of the WD in RU Peg. The X-ray luminosity we computed corresponds to a BL luminosity for a mass accretion rate of 2 Multiplication-Sign 10{sup -11} M{sub sun} yr{sup -1} (assuming M{sub wd} = 1.3 M{sub sun}), in agreement with the expected quiescent accretion rate. The modeling of the O VIII emission line at 19 A as observed by the Reflection Grating Spectrometer implies a projected stellar rotational velocity v{sub rot}sin i = 695 km s{sup -1}, i.e., the line is emitted from material rotating at {approx}936-1245 km s{sup -1} (i {approx} 34 Degree-Sign -48 Degree-Sign) or about 1/6 of the Keplerian speed; this velocity is much larger than the rotation speed of the WD inferred from the Far Ultraviolet Spectroscopic Explorer spectrum. Cross-correletion analysis yielded an undelayed (time lag {approx} 0) component and a delayed component of 116 {+-} 17 s where the X-ray variations/fluctuations lagged the UV variations. This indicates that the UV fluctuations in the inner disk are propagated into the X-ray emitting region in about 116 s. The undelayed component may be related to irradiation effects.

  8. Horizontal Velocity and Variance Measurements in the Stable Boundary Layer Using Doppler Lidar: Sensitivity to Averaging Procedures

    SciTech Connect (OSTI)

    Pichugina, Y. L.; Banta, R. M.; Kelley, N. D.; Jonkman, B. J.; Tucker, S. C.; Newsom, R. K.; Brewer, W. A.

    2008-08-01

    Quantitative data on turbulence variables aloft--above the region of the atmosphere conveniently measured from towers--have been an important but difficult measurement need for advancing understanding and modeling of the stable boundary layer (SBL). Vertical profiles of streamwise velocity variances obtained from NOAA's high-resolution Doppler lidar (HRDL), which have been shown to be approximately equal to turbulence kinetic energy (TKE) for stable conditions, are a measure of the turbulence in the SBL. In the present study, the mean horizontal wind component U and variance {sigma}2u were computed from HRDL measurements of the line-of-sight (LOS) velocity using a method described by Banta et al., which uses an elevation (vertical slice) scanning technique. The method was tested on datasets obtained during the Lamar Low-Level Jet Project (LLLJP) carried out in early September 2003, near the town of Lamar in southeastern Colorado. This paper compares U with mean wind speed obtained from sodar and sonic anemometer measurements. The results for the mean U and mean wind speed measured by sodar and in situ instruments for all nights of LLLJP show high correlation (0.71-0.97), independent of sampling strategies and averaging procedures, and correlation coefficients consistently >0.9 for four high-wind nights, when the low-level jet speeds exceeded 15 m s{sup -1} at some time during the night. Comparison of estimates of variance, on the other hand, proved sensitive to both the spatial and temporal averaging parameters. Several series of averaging tests are described, to find the best correlation between TKE calculated from sonic anemometer data at several tower levels and lidar measurements of horizontal-velocity variance {sigma}{sup 2}{sub u}. Because of the nonstationarity of the SBL data, the best results were obtained when the velocity data were first averaged over intervals of 1 min, and then further averaged over 3-15 consecutive 1-min intervals, with best results

  9. Reynolds number scaling of the influence of boundary layers on the global behavior of laboratory quasi-Keplerian flows

    SciTech Connect (OSTI)

    Edlund, E. M.; Ji, H.

    2015-10-06

    Here, we present fluid velocity measurements in a modified Taylor-Couette device operated in the quasi-Keplerian regime, where it is observed that nearly ideal flows exhibit self-similarity under scaling of the Reynolds number. In contrast, nonideal flows show progressive departure from ideal Couette as the Reynolds number is increased. We present a model that describes the observed departures from ideal Couette rotation as a function of the fluxes of angular momentum across the boundaries, capturing the dependence on Reynolds number and boundary conditions.

  10. On Techniques to Characterize and Correlate Grain Size, Grain Boundary Orientation and the Strength of the SiC Layer of TRISO Coated Particles: A Preliminary Study

    SciTech Connect (OSTI)

    I.J.van Rooyen; J.L. Dunzik Gougar; T. Trowbridge; Philip M van Rooyen

    2012-10-01

    The mechanical properties of the silicon carbide (SiC) layer of the TRi-ISOtropic (TRISO) coated particle (CP) for high temperature gas reactors (HTGR) are performance parameters that have not yet been standardized by the international HTR community. Presented in this paper are the results of characterizing coated particles to reveal the effect of annealing temperature (1000 to 2100C) on the strength and grain size of unirradiated coated particles. This work was further expanded to include possible relationships between the grain size and strength values. The comparative results of two strength measurement techniques and grain size measured by the Lineal intercept method are included. Preliminary grain boundary characterization results determined by electron backscatter diffraction (EBSD) are included. These results are also important for future fission product transport studies, as grain boundary diffusion is identified as a possible mechanism by which 110mAg, one of the fission activation products, might be released through intact SiC layers. Temperature is a parameter known to influence the grain size of SiC and therefore it is important to investigate the effect of high temperature annealing on the SiC grain size. Recommendations and future work will also be briefly discussed.

  11. Interface boundary conditions for dynamic magnetization and spin wave dynamics in a ferromagnetic layer with the interface Dzyaloshinskii-Moriya interaction

    SciTech Connect (OSTI)

    Kostylev, M.

    2014-06-21

    In this work, we derive the interface exchange boundary conditions for the classical linear dynamics of magnetization in ferromagnetic layers with the interface Dzyaloshinskii-Moriya interaction (IDMI). We show that IDMI leads to pinning of dynamic magnetization at the interface. An unusual peculiarity of the IDMI-based pinning is that its scales as the spin-wave wave number. We incorporate these boundary conditions into an existing numerical model for the dynamics of the Damon-Eshbach spin wave in ferromagnetic films. IDMI affects the dispersion and the frequency non-reciprocity of the travelling Damon-Eshbach spin wave. For a broad range of film thicknesses L and wave numbers, the results of the numerical simulations of the spin wave dispersion are in a good agreement with a simple analytical expression, which shows that the contribution of IDMI to the dispersion scales as 1/L, similarly to the effect of other types of interfacial anisotropy. Suggestions to experimentalists how to detect the presence of IDMI in a spin wave experiment are given.

  12. PULSE HEIGHT ANALYZER

    DOE Patents [OSTI]

    Goldsworthy, W.W.

    1958-06-01

    A differential pulse-height discriminator circuit is described which is readily adaptable for operation in a single-channel pulse-height analyzer. The novel aspect of the circuit lies in the specific arrangement of differential pulse-height discriminator which includes two pulse-height discriminators having a comnnon input and an anticoincidence circuit having two interconnected vacuum tubes with a common cathode resistor. Pulses from the output of one discriminator circuit are delayed and coupled to the grid of one of the anticoincidence tubes by a resistor. The output pulses from the other discriminator circuit are coupled through a cathode follower circuit, which has a cathode resistor of such value as to provide a long time constant with the interelectrode capacitance of the tube, to lenthen the output pulses. The pulses are then fed to the grid of the other anticoincidence tube. With such connections of the circuits, only when the incoming pulse has a pesk value between the operating levels of the two discriminators does an output pulse occur from the anticoincidence circuit.

  13. DIFFERENTIAL PULSE HEIGHT DISCRIMINATOR

    DOE Patents [OSTI]

    Test, L.D.

    1958-11-11

    Pulse-height discriminators are described, specifically a differential pulse-height discriminator which is adapted to respond to pulses of a band of amplitudes, but to reject pulses of amplitudes greater or less than tbe preselected band. In general, the discriminator includes a vacuum tube having a plurality of grids adapted to cut off plate current in the tube upon the application of sufficient negative voltage. One grid is held below cutoff, while a positive pulse proportional to the amplltude of each pulse is applled to this grid. Another grid has a negative pulse proportional to the amplitude of each pulse simultaneously applied to it. With this arrangement the tube will only pass pulses which are of sufficlent amplitude to counter the cutoff bias but not of sufficlent amplitude to cutoff the tube.

  14. VARIATIONS OF SOLAR ELECTRON AND PROTON FLUX IN MAGNETIC CLOUD BOUNDARY LAYERS AND COMPARISONS WITH THOSE ACROSS THE SHOCKS AND IN THE RECONNECTION EXHAUSTS

    SciTech Connect (OSTI)

    Wang, Y.; Wei, F. S.; Feng, X. S.; Zuo, P. B.; Guo, J. P.; Xu, X. J.; Li, Z.

    2012-04-10

    The magnetic cloud boundary layer (BL) is a dynamic region formed by the interaction of the magnetic cloud (MC) and the ambient solar wind. In the present study, we comparatively investigate the proton and electron mean flux variations in the BL, in the interplanetary reconnection exhaust (RE), and across the MC-driven shock by using the Wind data from 1995 to 2006. In general, the proton flux has higher increments at lower energy bands compared with the ambient solar wind. Inside the BL, the core electron flux increases quasi-isotropically and the increments decrease monotonously with energy from {approx}30% (at 18 eV) to {approx}10% (at 70 eV); the suprathermal electron flux usually increases in either parallel or antiparallel direction; the correlation coefficient of electron flux variations in parallel and antiparallel directions changes sharply from {approx}0.8 below 70 eV to {approx}0 above 70 eV. Similar results are also found for RE. However, different phenomena are found across the shock where the electron flux variations first increase and then decrease with a peak increment (>200%) near 100 eV. The correlation coefficient of electron flux variations in parallel and antiparallel directions is always around 0.8. The similar behavior of flux variations in BL and RE suggests that reconnection may commonly occur in BL. Our work also implies that the strong energy dependence and direction selectivity of electron flux variations, which were previously thought to have not enough relevance to magnetic reconnection, could be considered as an important signature of solar wind reconnection in the statistical point of view.

  15. PULSE HEIGHT ANALYZER

    DOE Patents [OSTI]

    Johnstone, C.W.

    1958-01-21

    An anticoincidence device is described for a pair of adjacent channels of a multi-channel pulse height analyzer for preventing the lower channel from generating a count pulse in response to an input pulse when the input pulse has sufficient magnitude to reach the upper level channel. The anticoincidence circuit comprises a window amplifier, upper and lower level discriminators, and a biased-off amplifier. The output of the window amplifier is coupled to the inputs of the discriminators, the output of the upper level discriminator is connected to the resistance end of a series R-C network, the output of the lower level discriminator is coupled to the capacitance end of the R-C network, and the grid of the biased-off amplifier is coupled to the junction of the R-C network. In operation each discriminator produces a negative pulse output when the input pulse traverses its voltage setting. As a result of the connections to the R-C network, a trigger pulse will be sent to the biased-off amplifier when the incoming pulse level is sufficient to trigger only the lower level discriminator.

  16. Pyramidal inversion domain boundaries revisited

    SciTech Connect (OSTI)

    Remmele, T.; Albrecht, M.; Irmscher, K.; Fornari, R.; Strassburg, M.

    2011-10-03

    The structure of pyramidal inversion domain boundaries in GaN:Mg was investigated by aberration corrected transmission electron microscopy. The analysis shows the upper (0001) boundary to consist of a single Mg layer inserted between polarity inverted GaN layers in an abcab stacking. The Mg bound in these defects is at least one order of magnitude lower than the chemical Mg concentration. Temperature dependent Hall effect measurements show that up to 27% of the Mg acceptors is electrically compensated.

  17. MULTICHANNEL PULSE-HEIGHT ANALYZER

    DOE Patents [OSTI]

    Russell, J.T.; Lefevre, H.W.

    1958-01-21

    This patent deals with electronic computing circuits and more particularly to pulse-height analyzers used for classifying variable amplitude pulses into groups of different amplitudes. The device accomplishes this pulse allocation by by converting the pulses into frequencies corresponding to the amplitudes of the pulses, which frequencies are filtered in channels individually pretuned to a particular frequency and then detected and recorded in the responsive channel. This circuit substantially overcomes the disadvantages of prior annlyzers incorporating discriminators pre-set to respond to certain voltage levels, since small variation in component values is not as critical to satisfactory circuit operation.

  18. Estimating vehicle height using homographic projections

    DOE Patents [OSTI]

    Cunningham, Mark F; Fabris, Lorenzo; Gee, Timothy F; Ghebretati, Jr., Frezghi H; Goddard, James S; Karnowski, Thomas P; Ziock, Klaus-peter

    2013-07-16

    Multiple homography transformations corresponding to different heights are generated in the field of view. A group of salient points within a common estimated height range is identified in a time series of video images of a moving object. Inter-salient point distances are measured for the group of salient points under the multiple homography transformations corresponding to the different heights. Variations in the inter-salient point distances under the multiple homography transformations are compared. The height of the group of salient points is estimated to be the height corresponding to the homography transformation that minimizes the variations.

  19. Systems and methods that generate height map models for efficient three dimensional reconstruction from depth information

    DOE Patents [OSTI]

    Frahm, Jan-Michael; Pollefeys, Marc Andre Leon; Gallup, David Robert

    2015-12-08

    Methods of generating a three dimensional representation of an object in a reference plane from a depth map including distances from a reference point to pixels in an image of the object taken from a reference point. Weights are assigned to respective voxels in a three dimensional grid along rays extending from the reference point through the pixels in the image based on the distances in the depth map from the reference point to the respective pixels, and a height map including an array of height values in the reference plane is formed based on the assigned weights. An n-layer height map may be constructed by generating a probabilistic occupancy grid for the voxels and forming an n-dimensional height map comprising an array of layer height values in the reference plane based on the probabilistic occupancy grid.

  20. Plant community composition and vegetation height, Barrow, Alaska, Ver. 1

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

    Sloan, Victoria; Norby, Richard; Siegrist, Julia; Iversen, Colleen; Brooks, Jonathan; Liebig, Jennifer; Wood, Sarah

    This dataset contains i) the results of field surveys of plant community composition and vegetation height made between 17th and 29th July 2012 in 48, 1 x 1 m plots located in areas A-D of Intensive Site 1 at the Next-Generation Ecosystem Experiments (NGEE) Arctic site near Barrow, Alaska and ii) results of a mapping exercise undertaken in August 2013 using two perpendicular transects across each polygon containing vegetation plots to determine the boundaries of vegetation communities described in 2012.

  1. Plant community composition and vegetation height, Barrow, Alaska, Ver. 1

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

    Sloan, Victoria; Norby, Richard; Siegrist, Julia; Iversen, Colleen; Brooks, Jonathan; Liebig, Jennifer; Wood, Sarah

    2014-04-25

    This dataset contains i) the results of field surveys of plant community composition and vegetation height made between 17th and 29th July 2012 in 48, 1 x 1 m plots located in areas A-D of Intensive Site 1 at the Next-Generation Ecosystem Experiments (NGEE) Arctic site near Barrow, Alaska and ii) results of a mapping exercise undertaken in August 2013 using two perpendicular transects across each polygon containing vegetation plots to determine the boundaries of vegetation communities described in 2012.

  2. Stable Boundary Layer Education Field Campaign Summary

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

    (STABLE) Final Campaign Summary DD Turner March 2016 DISCLAIMER This report was ... (STABLE) Final Campaign Summary DD Turner, National Oceanic and Atmospheric ...

  3. Retrieving 4-dimensional atmospheric boundary layer structure...

    Office of Scientific and Technical Information (OSTI)

    (BER) (SC-23) Country of Publication: United States Language: English Subject: 54 ENVIRONMENTAL SCIENCES Atmospheric System Research Word Cloud More Like This Full Text preview ...

  4. BOUndary Plasma Turbulence

    Energy Science and Technology Software Center (OSTI)

    2008-01-25

    BOUT is a parallelized 3D nonlocal electromagnetic turbulence code. The principal calculations are the boundary plasma turbulence in a realistic magnetic geometry. BOUT uses fluid Braginskii equations for plasma vorticity, density, electron and ion temperature and Parallel mementum. With sources added in the core-edge region and sinks in the scrape-off-layer (SOL), BOUT follows the self-consistent profile evolution together with turbulence. BOUT also includes coupling to a magnetohyfrodynamic equlibrium (EFIT package) and a two-dimensional hydrodynamic edgemore » transport model (UEDGE package).« less

  5. Evaluation of WRF predicted near hub-height winds and ramp events over a Pacific Northwest site with complex terrain

    SciTech Connect (OSTI)

    Yang, Qing; Berg, Larry K.; Pekour, Mikhail S.; Fast, Jerome D.; Newsom, Rob K.; Stoelinga, Mark; Finley, Cathy

    2013-08-16

    The WRF model version 3.3 is used to simulate near hub-height winds and power ramps utilizing three commonly used planetary boundary-layer (PBL) schemes: Mellor-Yamada-Janji? (MYJ), University of Washington (UW), and Yonsei University (YSU). The predicted winds have small mean biases compared with observations. Power ramps and step changes (changes within an hour) consistently show that the UW scheme performed better in predicting up ramps under stable conditions with higher prediction accuracy and capture rates. Both YSU and UW scheme show good performance predicting up- and down- ramps under unstable conditions with YSU being slightly better for ramp durations longer than an hour. MYJ is the most successful simulating down-ramps under stable conditions. The high wind speed and large shear associated with low-level jets are frequently associated with power ramps, and the biases in predicted low-level jet explain some of the shown differences in ramp predictions among different PBL schemes. Low-level jets were observed as low as ~200 m in altitude over the Columbia Basin Wind Energy Study (CBWES) site, located in an area of complex terrain. The shear, low-level peak wind speeds, as well as the height of maximum wind speed are not well predicted. Model simulations with 3 PBL schemes show the largest variability among them under stable conditions.

  6. Wind Turbine Scaling Enables Projects to Reach New Heights |...

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

    chapter that focuses on trends in wind turbine nameplate capacity, hub height, rotor ... chapter that focuses on trends in wind turbine nameplate capacity, hub height, rotor ...

  7. Mobility of charge carriers in porous silicon layers

    SciTech Connect (OSTI)

    Forsh, P. A. Martyshov, M. N.; Latysheva, A. P.; Vorontsov, A. S.; Timoshenko, V. Yu.; Kashkarov, P. K.

    2008-12-15

    The (conduction) mobility of majority charge carriers in porous silicon layers of the n and p types is estimated by joint measurements of electrical conductivity and free charge carrier concentration, which is determined from IR absorption spectra. Adsorption of donor and acceptor molecules leading to a change in local electric fields in the structure is used to identify the processes controlling the mobility in porous silicon. It is found that adsorption of acceptor and donor molecules at porous silicon of the p and n types, respectively, leads to a strong increase in electrical conductivity, which is associated with an increase in the concentration of free carrier as well as in their mobility. The increase in the mobility of charge carriers as a result of adsorption indicates the key role of potential barriers at the boundaries of silicon nanocrystals and may be due to a decrease in the barrier height as a result of adsorption.

  8. MULTI-CHANNEL PULSE HEIGHT ANALYZER

    DOE Patents [OSTI]

    Boyer, K.; Johnstone, C.W.

    1958-11-25

    An improved multi-channel pulse height analyzer of the type where the device translates the amplitude of each pulse into a time duration electrical quantity which is utilized to control the length of a train of pulses forwarded to a scaler is described. The final state of the scaler for any one train of pulses selects the appropriate channel in a magnetic memory in which an additional count of one is placed. The improvement consists of a storage feature for storing a signal pulse so that in many instances when two signal pulses occur in rapid succession, the second pulse is preserved and processed at a later time.

  9. Property:Maximum Wave Height(m) | Open Energy Information

    Open Energy Info (EERE)

    Jump to: navigation, search Property Name Maximum Wave Height(m) Property Type String Pages using the property "Maximum Wave Height(m)" Showing 25 pages using this property....

  10. A new technique to measure tunneling barrier height in solid...

    Office of Scientific and Technical Information (OSTI)

    A new technique to measure tunneling barrier height in solid media Citation Details In-Document Search Title: A new technique to measure tunneling barrier height in solid media ...

  11. Indium Growth and Island Height Control on Si Submonolayer Phases

    SciTech Connect (OSTI)

    Chen, Jizhou

    2009-05-09

    wave length of 13.4nm so it can curve on the surface of an sample to make structure as small as the order of 10nm. however, lithograph usually causes permanent damages to the surface and in many cases the QDs are damaged during the lithograph and therefore result in high percentage of defects. Quantum size effect has attracted more and more interests in surface science due to many of its effects. One of its effects is the height preference in film growing and the resulting possibility of uniformly sized self-assemble nanostructure. The experiment of Pb islands on In 4x1 phase shows that both the height and the width can be controlled by proper growth conditions, which expands the growth dimensions from 1 to 2. This discover leads us to study the In/Pb interface. In Ch.3, we found that the Pb islands growing on In 4x1-Si(111) surface which have uniform height due to QSE and uniform width due to the constriction of In 4x1 lattice have unexpected stability. These islands are stable in even RT, unlike usual nanostructures on Pb/Si surface which are stable only at low temperature. Since similar structures are usually grown at low temperature, this discovery makes the grown structures closer to technological applications. It also shows the unusual of In/Pb interface. Then we studied the In islands grown on Pb-{alpha}-{radical}3x{radical}3-Si(111) phase in Ch.4. These islands have fcc structure in the first few layers, and then convert to bct structure. The In fcc islands have sharp height preference due to QSE like Pb islands. However, the preferred height is different (7 layer for Pb on Si 7x7 and 4 layer for Pb on In 4x1), due to the difference of interface. The In islands structure prefers to be bct than fcc with coverage increase. It is quantitatively supported by first-principle calculation. Unexpectedly, the In islands grown on various of In interfaces didn't show QSE effects and phase transition from fcc and bct structures as on the Pb-{alpha} interface (Ch.6). In g

  12. Barker Heights, North Carolina: Energy Resources | Open Energy...

    Open Energy Info (EERE)

    Barker Heights, North Carolina: Energy Resources Jump to: navigation, search Equivalent URI DBpedia Coordinates 35.3112279, -82.444008 Show Map Loading map......

  13. East Richmond Heights, California: Energy Resources | Open Energy...

    Open Energy Info (EERE)

    Richmond Heights, California: Energy Resources Jump to: navigation, search Equivalent URI DBpedia Coordinates 37.944924, -122.3135811 Show Map Loading map......

  14. University Heights, Ohio: Energy Resources | Open Energy Information

    Open Energy Info (EERE)

    University Heights, Ohio: Energy Resources Jump to: navigation, search Equivalent URI DBpedia Coordinates 41.4978306, -81.5373456 Show Map Loading map... "minzoom":false,"mapp...

  15. Alamo Heights, Texas: Energy Resources | Open Energy Information

    Open Energy Info (EERE)

    Alamo Heights, Texas: Energy Resources Jump to: navigation, search Equivalent URI DBpedia Coordinates 29.4849531, -98.4658502 Show Map Loading map... "minzoom":false,"mappings...

  16. Microscopic Description of Nuclear Fission: Fission Barrier Heights...

    Office of Scientific and Technical Information (OSTI)

    Conference: Microscopic Description of Nuclear Fission: Fission Barrier Heights of Even-Even Actinides Citation Details In-Document Search Title: Microscopic Description of Nuclear ...

  17. Ben Avon Heights, Pennsylvania: Energy Resources | Open Energy...

    Open Energy Info (EERE)

    Avon Heights, Pennsylvania: Energy Resources Jump to: navigation, search Equivalent URI DBpedia Coordinates 40.5136795, -80.0731112 Show Map Loading map......

  18. Huber Heights, Ohio: Energy Resources | Open Energy Information

    Open Energy Info (EERE)

    by expanding it. Huber Heights is a city in Greene County and Miami County and Montgomery County, Ohio. It falls under Ohio's 8th congressional district.12 References ...

  19. Drexel Heights, Arizona: Energy Resources | Open Energy Information

    Open Energy Info (EERE)

    Drexel Heights, Arizona: Energy Resources Jump to: navigation, search Equivalent URI DBpedia Coordinates 32.1411888, -111.028427 Show Map Loading map... "minzoom":false,"mappi...

  20. NREL: Wind Research - New Wind Resource Maps Reach Higher Heights

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

    capacity map at a 140-meter hub height. Photo courtesy of WINDExchange August 11, 2015 The National Renewable Energy Laboratory and AWS Truepower LLC recently released maps...

  1. Optimized capping layers for EUV multilayers

    DOE Patents [OSTI]

    Bajt, Sasa; Folta, James A.; Spiller, Eberhard A.

    2004-08-24

    A new capping multilayer structure for EUV-reflective Mo/Si multilayers consists of two layers: A top layer that protects the multilayer structure from the environment and a bottom layer that acts as a diffusion barrier between the top layer and the structure beneath. One embodiment combines a first layer of Ru with a second layer of B.sub.4 C. Another embodiment combines a first layer of Ru with a second layer of Mo. These embodiments have the additional advantage that the reflectivity is also enhanced. Ru has the best oxidation resistance of all materials investigated so far. B.sub.4 C is an excellent barrier against silicide formation while the silicide layer formed at the Si boundary is well controlled.

  2. Joint retrievals of cloud and drizzle in marine boundary layer...

    Office of Scientific and Technical Information (OSTI)

    Specifically, the vertical structure of droplet size and water content of both cloud and ... cumulus under stratocumulus, where cloud water path is retrieved with an error of 31 g ...

  3. RACORO continental boundary layer cloud investigations. 2. Large...

    Office of Scientific and Technical Information (OSTI)

    Facility AAF Clouds with Low Optical Water Depths CLOWD Optical Radiative ... droplet number concentration with liquid water content (LWC), corresponding to the ...

  4. Clouds, Precipitation, and Marine Boundary Layer Structure during...

    Office of Scientific and Technical Information (OSTI)

    Authors: Zhou, Xiaoli 1 ; Kollias, Pavlos 1 ; Lewis, Ernie R. 2 + Show Author Affiliations McGill Univ., Montreal, Quebec (Canada); Dept. of Atmospheric and Oceanic Sciences ...

  5. On the Interaction between Marine Boundary Layer Cellular Cloudiness...

    Office of Scientific and Technical Information (OSTI)

    The investigation focuses on the non-precipitating closed-cell state and the precipitating open-cell state at low geostrophic wind speed. The Advanced Research WRF model is used to ...

  6. Clouds, Aerosol, and Precipitation in the Marine Boundary Layer...

    Office of Scientific and Technical Information (OSTI)

    These couplings have been documented as a result of past field programs and model studies. However, extensive research is still required to achieve a quantitative understanding ...

  7. RACORO Extended-Term Aircraft Observations of Boundary-Layer...

    Office of Scientific and Technical Information (OSTI)

    the Routine AAF Clouds with Low Optical Water Depths (CLOWD) Optical Radiative ... SURFACES; THERMAL RADIATION; USA; WATER RACORO Extended-Term; Aircraft ...

  8. Stable Boundary Layer Education (STABLE) Final Campaign Summary...

    Office of Scientific and Technical Information (OSTI)

    Close Cite: Bibtex Format Close 0 pages in this document matching the terms "" Search For Terms: Enter terms in the toolbar above to search the full text of this document for ...

  9. RACORO continental boundary layer cloud investigations. 3. Separation...

    Office of Scientific and Technical Information (OSTI)

    Brookhaven National Lab. (BNL), Upton, NY (United States) NASA Goddard Space Flight Center (GSFC), Greenbelt, MD (United States) UCLA Joint Institute for Regional Earth System ...

  10. RACORO continental boundary layer cloud investigations. 2. Large...

    Office of Scientific and Technical Information (OSTI)

    Brookhaven National Lab. (BNL), Upton, NY (United States) NASA Goddard Inst. for Space Studies (GISS), New York, NY (United States) Univ. of Illinois, Urbana, IL (United States) ...

  11. Clouds, Aerosol, and Precipitation in the Marine Boundary Layer...

    Office of Scientific and Technical Information (OSTI)

    Close Cite: Bibtex Format Close 0 pages in this document matching the terms "" Search For Terms: Enter terms in the toolbar above to search the full text of this document for ...

  12. Posters Triggering of Boundary Layer Cumulus Clouds Over a Heterogeneo...

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

    distribution, and the parameters can be objectively determined with a relatively straightforward maximum-likelihood statistical fitting method. For the whole grid-cell domain,...

  13. Clouds, Aerosols, and Precipitation in the Marine Boundary Layer...

    Office of Scientific and Technical Information (OSTI)

    ; Stemmler, Jayson ; de Szoeke, Simone ; Yuter, Sandra ; Miller, Matthew ; Mechem, David ; Tselioudis, George ; Chiu, J. Christine ; Mann, Julian A. L. ; O'Connor, Ewan J. ; ...

  14. Clouds, aerosol, and precipitation in the Marine Boundary Layer...

    Office of Scientific and Technical Information (OSTI)

    Jayson 1 ; deSzoeke, S. 5 ; Yuter, Sandra 6 ; Miller, Matthew 6 ; Mechem, David 7 ; Tselioudis, George 3 ; Chiu, Christine 8 ; Mann, Julia 8 ; O Connor, ...

  15. Four-Dimensional Data Assimilation Boundary-Layer Observations...

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

    ... The profiler was operated in Doppler beam swinging (DBS) mode while also processing the signal using interferometry . Radiosondes were launched from both the central facility and ...

  16. Lower Atmospheric Boundary Layer Experiment (LABLE) Final Campaign...

    Office of Scientific and Technical Information (OSTI)

    Severe Storms Laboratory, Lawrence Livermore National Laboratory, and the ARM program. ... University of Oklahoma Lawrence Livermore National Laboratory Publication Date: ...

  17. Codes for Unfolding Activation Detector Data and Pulse Height Spectra.

    Energy Science and Technology Software Center (OSTI)

    1980-01-30

    Version 00 ITER-2 includes two versions of the ITER code; these are ITERAD and ITERMS. ITER-2 was previously used for unfolding data from neutron activation detectors; it is now capable, also, of unfolding pulse height spectra.

  18. Perry Heights, Ohio: Energy Resources | Open Energy Information

    Open Energy Info (EERE)

    Hide Map This article is a stub. You can help OpenEI by expanding it. Perry Heights is a census-designated place in Stark County, Ohio.1 References US...

  19. Richmond Heights, Florida: Energy Resources | Open Energy Information

    Open Energy Info (EERE)

    Hide Map This article is a stub. You can help OpenEI by expanding it. Richmond Heights is a census-designated place in Miami-Dade County, Florida.1 References ...

  20. Wind Turbine Inspection Technology Reaches New Heights | GE Global...

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

    Wind Turbine Inspection Technology Reaches New Heights Click to email this to a friend (Opens in new window) Share on Facebook (Opens in new window) Click to share (Opens in new ...

  1. Vadnais Heights, Minnesota: Energy Resources | Open Energy Information

    Open Energy Info (EERE)

    article is a stub. You can help OpenEI by expanding it. Vadnais Heights is a city in Ramsey County, Minnesota. It falls under Minnesota's 4th congressional district.12...

  2. Windsor Heights, Iowa: Energy Resources | Open Energy Information

    Open Energy Info (EERE)

    article is a stub. You can help OpenEI by expanding it. Windsor Heights is a city in Polk County, Iowa. It falls under Iowa's 3rd congressional district.12 References US...

  3. San Antonio Heights, California: Energy Resources | Open Energy...

    Open Energy Info (EERE)

    Hide Map This article is a stub. You can help OpenEI by expanding it. San Antonio Heights is a census-designated place in San Bernardino County, California.1...

  4. Porter Heights, Texas: Energy Resources | Open Energy Information

    Open Energy Info (EERE)

    You can help OpenEI by expanding it. Porter Heights is a census-designated place in Montgomery County, Texas.1 References US Census Bureau 2005 Place to 2006 CBSA Retrieved...

  5. Federal Heights, Colorado: Energy Resources | Open Energy Information

    Open Energy Info (EERE)

    article is a stub. You can help OpenEI by expanding it. Federal Heights is a city in Adams County, Colorado. It falls under Colorado's 2nd congressional district.12...

  6. Property:Building/InteriorHeight | Open Energy Information

    Open Energy Info (EERE)

    InteriorHeight" Showing 25 pages using this property. (previous 25) (next 25) S Sweden Building 05K0001 + 3.5 + Sweden Building 05K0002 + 3 + Sweden Building 05K0003 + 3 +...

  7. Maple Heights-Lake Desire, Washington: Energy Resources | Open...

    Open Energy Info (EERE)

    help OpenEI by expanding it. Maple Heights-Lake Desire is a census-designated place in King County, Washington.1 References US Census Bureau 2005 Place to 2006 CBSA...

  8. Control of bed height in a fluidized bed gasification system

    DOE Patents [OSTI]

    Mehta, Gautam I.; Rogers, Lynn M.

    1983-12-20

    In a fluidized bed apparatus a method for controlling the height of the fdized bed, taking into account variations in the density of the bed. The method comprises taking simultaneous differential pressure measurements at different vertical elevations within the vessel, averaging the differential pressures, determining an average fluidized bed density, then periodically calculating a weighting factor. The weighting factor is used in the determination of the actual bed height which is used in controlling the fluidizing means.

  9. DOE Taking Wind Forecasting to New Heights | Department of Energy

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

    Taking Wind Forecasting to New Heights DOE Taking Wind Forecasting to New Heights May 18, 2015 - 3:24pm Addthis A 2013 study conducted for the U.S. Department of Energy (DOE) by the National Oceanic and Atmospheric Administration (NOAA), AWS Truepower, and WindLogics in the Great Plains and Western Texas, demonstrated that wind power forecasts can be improved substantially using data collected from tall towers, remote sensors, and other devices, and incorporated into improved forecasting models

  10. 'Data Deluge' Pushes Mass Spec Imaging to New Heights

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

    'Data Deluge' Pushes Mass Spec Imaging to New Heights 'Data Deluge' Pushes Mass Spec Imaging to New Heights MANTISSA Team Takes Novel Approach to Improve Experimental Data Analysis July 15, 2015 Contact: Kathy Kincade, +1 510 495 2124, kkincade@lbl.gov MANTISSA Ion-intensity visualization of the 20 most important ions in a mouse brain segment selected by the CX/CUR algorithm. Of the 20 ions, little redundancy is present, pointing to the effectiveness of the CX approach for information

  11. Could crop height affect the wind resource at agriculturally productive wind farm sites?

    SciTech Connect (OSTI)

    Vanderwende, Brian; Lundquist, Julie K.

    2015-11-07

    The collocation of cropland and wind turbines in the US Midwest region introduces complex meteorological interactions that could influence both agriculture and wind-power production. Crop management practices may affect the wind resource through alterations of land-surface properties. We use the weather research and forecasting (WRF) model to estimate the impact of crop height variations on the wind resource in the presence of a large turbine array. A hypothetical wind farm consisting of 121 1.8-MW turbines is represented using the WRF model wind-farm parametrization. We represent the impact of selecting soybeans rather than maize by altering the aerodynamic roughness length in a region approximately 65 times larger than that occupied by the turbine array. Roughness lengths of 0.1 and 0.25 m represent the mature soy crop and a mature maize crop, respectively. In all but the most stable atmospheric conditions, statistically significant hub-height wind-speed increases and rotor-layer wind-shear reductions result from switching from maize to soybeans. Based on simulations for the entire month of August 2013, wind-farm energy output increases by 14 %, which would yield a significant monetary gain. Further investigation is required to determine the optimal size, shape, and crop height of the roughness modification to maximize the economic benefit and minimize the cost of such crop-management practices. As a result, these considerations must be balanced by other influences on crop choice such as soil requirements and commodity prices.

  12. Boundary Plasma Turbulence Simulations for Tokamaks

    SciTech Connect (OSTI)

    Xu, X; Umansky, M; Dudson, B; Snyder, P

    2008-05-15

    The boundary plasma turbulence code BOUT models tokamak boundary-plasma turbulence in a realistic divertor geometry using modified Braginskii equations for plasma vorticity, density (ni), electron and ion temperature (T{sub e}; T{sub i}) and parallel momenta. The BOUT code solves for the plasma fluid equations in a three dimensional (3D) toroidal segment (or a toroidal wedge), including the region somewhat inside the separatrix and extending into the scrape-off layer; the private flux region is also included. In this paper, a description is given of the sophisticated physical models, innovative numerical algorithms, and modern software design used to simulate edge-plasmas in magnetic fusion energy devices. The BOUT code's unique capabilities and functionality are exemplified via simulations of the impact of plasma density on tokamak edge turbulence and blob dynamics.

  13. Cell boundary fault detection system

    DOE Patents [OSTI]

    Archer, Charles Jens; Pinnow, Kurt Walter; Ratterman, Joseph D.; Smith, Brian Edward

    2009-05-05

    A method determines a nodal fault along the boundary, or face, of a computing cell. Nodes on adjacent cell boundaries communicate with each other, and the communications are analyzed to determine if a node or connection is faulty.

  14. ARM: X-SAPR Range Height Indicator scan (Dataset) | Data Explorer

    Office of Scientific and Technical Information (OSTI)

    Data Explorer Search Results ARM: X-SAPR Range Height Indicator scan Title: ARM: X-SAPR Range Height Indicator scan X-SAPR Range Height Indicator scan Authors: Widener, Kevin ; ...

  15. Could crop height affect the wind resource at agriculturally productive wind farm sites?

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

    Vanderwende, Brian; Lundquist, Julie K.

    2015-11-07

    The collocation of cropland and wind turbines in the US Midwest region introduces complex meteorological interactions that could influence both agriculture and wind-power production. Crop management practices may affect the wind resource through alterations of land-surface properties. We use the weather research and forecasting (WRF) model to estimate the impact of crop height variations on the wind resource in the presence of a large turbine array. A hypothetical wind farm consisting of 121 1.8-MW turbines is represented using the WRF model wind-farm parametrization. We represent the impact of selecting soybeans rather than maize by altering the aerodynamic roughness length inmore » a region approximately 65 times larger than that occupied by the turbine array. Roughness lengths of 0.1 and 0.25 m represent the mature soy crop and a mature maize crop, respectively. In all but the most stable atmospheric conditions, statistically significant hub-height wind-speed increases and rotor-layer wind-shear reductions result from switching from maize to soybeans. Based on simulations for the entire month of August 2013, wind-farm energy output increases by 14 %, which would yield a significant monetary gain. Further investigation is required to determine the optimal size, shape, and crop height of the roughness modification to maximize the economic benefit and minimize the cost of such crop-management practices. As a result, these considerations must be balanced by other influences on crop choice such as soil requirements and commodity prices.« less

  16. Building Height-Characteristics in Three U.S. Cities

    SciTech Connect (OSTI)

    Burian, S. J.; Brown, M. J.; Velugubantla, S. P.

    2002-01-01

    Urban canopy parameterizations have been used to represent urban effects in numerical models of mesoscale meteorology, the surface energy budget, and pollutant dispersion. The urban canopy parameterization accounts for the drag exerted by urban roughness elements, the enhancement of turbulent kinetic energy, and the alteration of the surface energy budget (Brown 2000). Accurate representation of urban effects in numerical simulations requires the determination of urban morphological parameters, including building height statistics. Computer analysis of 3-D building digital datasets can provide details of the urban environment in an efficient manner. Ratti ut al. (2001) describe a method for obtaining urban canopy parameters from digital imagery using image processing techniques, Burian et al. (2002) present an alternative analysis approach using a geographic information system (GIS). In this paper, building height statistics computed for three U.S. cities following the GIS approach are presented.

  17. Limiting Factors for Convective Cloud Top Height in the Tropics

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

    Limiting Factors for Convective Cloud Top Height in the Tropics M. P. Jensen and A. D. Del Genio National Aeronautics and Space Administration Goddard Institute for Space Studies Columbia University New York, New York Introduction Populations of tropical convective clouds are mainly comprised of three types: shallow trade cumulus, mid-level cumulus congestus and deep convective clouds (Johnson et al. 1999). Each of these cloud types has different impacts on the local radiation and water budgets.

  18. Process for preparing schottky diode contacts with predetermined barrier heights

    DOE Patents [OSTI]

    Chang, Y. Austin; Jan, Chia-Hong; Chen, Chia-Ping

    1996-01-01

    A process is provided for producing a Schottky diode having a preselected barrier height .phi..sub.Bn. The substrate is preferably n-GaAs, the metallic contact is derived from a starting alloy of the Formula [.SIGMA.M.sub..delta. ](Al.sub.x Ga.sub.1-x) wherein: .SIGMA.M is a moiety which consists of at least one M, and when more than one M is present, each M is different, M is a Group VIII metal selected from the group consisting of nickel, cobalt, ruthenium, rhodium, indium and platinum, .delta. is a stoichiometric coefficient whose total value in any given .SIGMA.M moiety is 1, and x is a positive number between 0 and 1 (that is, x ranges from greater than 0 to less than 1). Also, the starting alloy is capable of forming with the substrate a two phase equilibrium reciprocal system of the binary alloy mixture [.SIGMA.M.sub..delta. ]Ga-[.SIGMA.M.sub..delta. ]Al-AlAs-GaAs. When members of an alloy subclass within this Formula are each preliminarily correlated with the barrier height .phi..sub.Bn of a contact producable therewith, then Schottky diodes of predetermined barrier heights are producable by sputtering and annealing. Further provided are the product Schottky diodes that are produced according to this process.

  19. Cell boundary fault detection system

    DOE Patents [OSTI]

    Archer, Charles Jens; Pinnow, Kurt Walter; Ratterman, Joseph D.; Smith, Brian Edward

    2011-04-19

    An apparatus and program product determine a nodal fault along the boundary, or face, of a computing cell. Nodes on adjacent cell boundaries communicate with each other, and the communications are analyzed to determine if a node or connection is faulty.

  20. Gradient zone boundary control in salt gradient solar ponds

    DOE Patents [OSTI]

    Hull, John R.

    1984-01-01

    A method and apparatus for suppressing zone boundary migration in a salt gradient solar pond includes extending perforated membranes across the pond at the boundaries, between the convective and non-convective zones, the perforations being small enough in size to prevent individual turbulence disturbances from penetrating the hole, but being large enough to allow easy molecular diffusion of salt thereby preventing the formation of convective zones in the gradient layer. The total area of the perforations is a sizable fraction of the membrane area to allow sufficient salt diffusion while preventing turbulent entrainment into the gradient zone.

  1. ARM - VAP Product - pblhtsondeyr1mcfarl

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

    height Planetary boundary layer height above mean sea level calculated from bulk Richardson number using critical threshold of 0.5 m pblheightbulkrichardsonpt5 ( time )...

  2. Electrode size and boundary condition independent measurement of the effective piezoelectric coefficient of thin films

    SciTech Connect (OSTI)

    Stewart, M.; Lepadatu, S.; McCartney, L. N.; Cain, M. G.; Wright, L.; Crain, J.; Newns, D. M.; Martyna, G. J.

    2015-02-01

    The determination of the piezoelectric coefficient of thin films using interferometry is hindered by bending contributions. Using finite element analysis (FEA) simulations, we show that the Lefki and Dormans approximations using either single or double-beam measurements cannot be used with finite top electrode sizes. We introduce a novel method for characterising piezoelectric thin films which uses a differential measurement over the discontinuity at the electrode edge as an internal reference, thereby eliminating bending contributions. This step height is shown to be electrode size and boundary condition independent. An analytical expression is derived which gives good agreement with FEA predictions of the step height.

  3. Charge Transport Anisotropy Due to Grain Boundaries in Directionally

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

    Crystallized Thin Films of Regio-Regular Poly(3-hexylthiophene) Charge Transport Anisotropy Due to Grain Boundaries in Directionally Crystallized Thin Films of Regio-Regular Poly(3-hexylthiophene) Semicrystalline polymers, such as polythiophenes, hold much promise as active layers in printable electronic devices such as photovoltaic cells, sensors, and thin film transistors. As organic semiconductors approach commercialization, there is a need to better understand the relationship between

  4. EIS-0505: Vantage to Pomona Heights 230 kV Transmission Line...

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

    5: Vantage to Pomona Heights 230 kV Transmission Line Project; Yakima, Grant, Benton, and Kittitas Counties, Washington EIS-0505: Vantage to Pomona Heights 230 kV Transmission Line ...

  5. Property:Maximum Wave Height(m) at Wave Period(s) | Open Energy...

    Open Energy Info (EERE)

    at Wave Period(s) Jump to: navigation, search Property Name Maximum Wave Height(m) at Wave Period(s) Property Type String Pages using the property "Maximum Wave Height(m) at Wave...

  6. 23 V.S.A. Section 1431 Height and Width Limits | Open Energy...

    Open Energy Info (EERE)

    search OpenEI Reference LibraryAdd to library Legal Document- StatuteStatute: 23 V.S.A. Section 1431 Height and Width LimitsLegal Abstract Limits for the height and width...

  7. Dilution calculations for determining laboratory exhaust stack heights

    SciTech Connect (OSTI)

    Ratcliff, M.A.; Sandru, E.

    1999-07-01

    Laboratory exhaust stacks should be designed with sufficient height and exit momentum to avoid re-entry of exhaust and possible air quality problems, and the design should be evaluated before construction. One evaluation method is presented in this paper that combines dilution prediction equations from the 1997 ASHRAE Handbook--Fundamentals (1997) and a dilution criteria of Halitsky (1988). This method is less conservative than a geometric method in the ASHRAE Handbook and is less costly than wind-tunnel modeling. The method should only be applied to relatively simple building geometries with no larger buildings adjacent to them. A planned change to the ASHRAE equations, which would result in larger stacks being necessary, is discussed. Further investigation of this change is recommended using comparisons to wind tunnel data.

  8. The physics and chemistry of the Schottky barrier height

    SciTech Connect (OSTI)

    Tung, Raymond T.

    2014-03-15

    The formation of the Schottky barrier height (SBH) is a complex problem because of the dependence of the SBH on the atomic structure of the metal-semiconductor (MS) interface. Existing models of the SBH are too simple to realistically treat the chemistry exhibited at MS interfaces. This article points out, through examination of available experimental and theoretical results, that a comprehensive, quantum-mechanics-based picture of SBH formation can already be constructed, although no simple equations can emerge, which are applicable for all MS interfaces. Important concepts and principles in physics and chemistry that govern the formation of the SBH are described in detail, from which the experimental and theoretical results for individual MS interfaces can be understood. Strategies used and results obtained from recent investigations to systematically modify the SBH are also examined from the perspective of the physical and chemical principles of the MS interface.

  9. Photovoltaic devices comprising zinc stannate buffer layer and method for making

    DOE Patents [OSTI]

    Wu, Xuanzhi; Sheldon, Peter; Coutts, Timothy J.

    2001-01-01

    A photovoltaic device has a buffer layer zinc stannate Zn.sub.2 SnO.sub.4 disposed between the semiconductor junction structure and the transparent conducting oxide (TCO) layer to prevent formation of localized junctions with the TCO through a thin window semiconductor layer, to prevent shunting through etched grain boundaries of semiconductors, and to relieve stresses and improve adhesion between these layers.

  10. Photonic layered media

    DOE Patents [OSTI]

    Fleming, James G.; Lin, Shawn-Yu

    2002-01-01

    A new class of structured dielectric media which exhibit significant photonic bandstructure has been invented. The new structures, called photonic layered media, are easy to fabricate using existing layer-by-layer growth techniques, and offer the ability to significantly extend our practical ability to tailor the properties of such optical materials.

  11. Potential variation around grain boundaries in BaSi{sub 2} films grown on multicrystalline silicon evaluated using Kelvin probe force microscopy

    SciTech Connect (OSTI)

    Baba, Masakazu; Tsukahara, Daichi; Toko, Kaoru; Hara, Kosuke O.; Usami, Noritaka; Sekiguchi, Takashi; Suemasu, Takashi

    2014-12-21

    Potential variations across the grain boundaries (GBs) in a 100?nm thick undoped n-BaSi{sub 2} film on a cast-grown multicrystalline Si (mc-Si) substrate are evaluated using Kelvin probe force microscopy (KFM). The ?-2? X-ray diffraction pattern reveals diffraction peaks, such as (201), (301), (410), and (411) of BaSi{sub 2}. Local-area electron backscatter diffraction reveals that the a-axis of BaSi{sub 2} is tilted slightly from the surface normal, depending on the local crystal plane of the mc-Si. KFM measurements show that the potentials are not significantly disordered in the grown BaSi{sub 2}, even around the GBs of mc-Si. The potentials are higher at GBs of BaSi{sub 2} around Si GBs that are formed by grains with a Si(111) face and those with faces that deviate slightly from Si(111). Thus, downward band bending occurs at these BaSi{sub 2} GBs. Minority carriers (holes) undergo a repelling force near the GBs, which may suppress recombination as in the case of undoped n-BaSi{sub 2} epitaxial films on a single crystal Si(111) substrate. The barrier height for hole transport across the GBs varies in the range from 10 to 55?meV. The potentials are also higher at the BaSi{sub 2} GBs grown around Si GBs composed of grains with Si(001) and Si(111) faces. The barrier height for hole transport ranges from 5 to 55?meV. These results indicate that BaSi{sub 2} GBs formed on (111)-dominant Si surfaces do not have a negative influence on the minority-carrier properties, and thus BaSi{sub 2} formed on underlayers, such as (111)-oriented Si or Ge and on (111)-oriented mc-Si, can be utilized as a solar cell active layer.

  12. Scintillator reflective layer coextrusion

    DOE Patents [OSTI]

    Yun, Jae-Chul; Para, Adam

    2001-01-01

    A polymeric scintillator has a reflective layer adhered to the exterior surface thereof. The reflective layer comprises a reflective pigment and an adhesive binder. The adhesive binder includes polymeric material from which the scintillator is formed. A method of forming the polymeric scintillator having a reflective layer adhered to the exterior surface thereof is also provided. The method includes the steps of (a) extruding an inner core member from a first amount of polymeric scintillator material, and (b) coextruding an outer reflective layer on the exterior surface of the inner core member. The outer reflective layer comprises a reflective pigment and a second amount of the polymeric scintillator material.

  13. Irradiation Assisted Grain Boundary Segregation in Steels

    SciTech Connect (OSTI)

    Lu, Zheng; Faulkner, Roy G.

    2008-07-01

    The understanding of radiation-induced grain boundary segregation (RIS) has considerably improved over the past decade. New models have been introduced and much effort has been devoted to obtaining comprehensive information on segregation from the literature. Analytical techniques have also improved so that chemical analysis of layers 1 nm thick is almost routine. This invited paper will review the major methods used currently for RIS prediction: namely, Rate Theory, Inverse Kirkendall, and Solute Drag approaches. A summary is made of the available data on phosphorus RIS in reactor pressure vessel (RPV) steels. This will be discussed in the light of the predictions of the various models in an effort to show which models are the most reliable and easy to use for forecasting P segregation behaviour in steels. A consequence of RIS in RPV steels is a radiation induced shift in the ductile to brittle transition temperature (DBTT). It will be shown how it is possible to relate radiation-induced P segregation levels to DBTT shift. Examples of this exercise will be given for RPV steels and for ferritic steels being considered for first wall fusion applications. Cr RIS in high alloy stainless steels and associated irradiation-assisted stress corrosion cracking (IASCC) will be briefly discussed. (authors)

  14. Correlations between In Situ Conductivity and Uniform-Height Epitaxial Morphology in Pb/Si(111)₋(7×7)

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

    Jałochowski, M.; Zdyb, R.; Tringides, M. C.

    2016-02-23

    The growth of Pb on Si(111)-7x7 at temperatures from 72 K to 201 K has been investigated using in situ electrical resistivity measurements and Scanning Tunneling Microscopy (STM). For temperatures T>140 K the specific resistivity ρ(θ) vs coverage θ shows an unusual "hump", instead of the expected monotonic decrease with θ. This novel result correlates well with the formation of uniform height 8-layer Pb islands and the superdiffusive motion of the wetting layer, despite the low temperatures. A model of the film resistivity as two resistors in series, the amorphous wetting layer and the crystalline islands, explains quantitatively the resistivitymore » dependence on θ.« less

  15. Plasma Boundary Colloquium.key

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

    Excitement at the Plasma Boundary Rob Goldston (with help from many) Fusion Plasma Physics is as Easy as 1-2-3 3)Manage the heat outflux 2)Hold onto the heat & amplify it by fusion 1)Inject heat into plasma Inject Heat into Plasma We put 40 MW of neutral beams into TFTR. Heating was ~ classical, with some *AE's, fishbones, etc. ITER needs ~ 2x more heating. Projections pretty reliable with multiple types of heating systems planned. Mike Williams Hold onto the heat... Empirical scaling

  16. Layered plasma polymer composite membranes

    DOE Patents [OSTI]

    Babcock, W.C.

    1994-10-11

    Layered plasma polymer composite fluid separation membranes are disclosed, which comprise alternating selective and permeable layers for a total of at least 2n layers, where n is [>=]2 and is the number of selective layers. 2 figs.

  17. Layered plasma polymer composite membranes

    DOE Patents [OSTI]

    Babcock, Walter C.

    1994-01-01

    Layered plasma polymer composite fluid separation membranes are disclosed, which comprise alternating selective and permeable layers for a total of at least 2n layers, where n is .gtoreq.2 and is the number of selective layers.

  18. Multiple density layered insulator

    DOE Patents [OSTI]

    Alger, Terry W.

    1994-01-01

    A multiple density layered insulator for use with a laser is disclosed wh provides at least two different insulation materials for a laser discharge tube, where the two insulation materials have different thermoconductivities. The multiple layer insulation materials provide for improved thermoconductivity capability for improved laser operation.

  19. Multiple density layered insulator

    DOE Patents [OSTI]

    Alger, T.W.

    1994-09-06

    A multiple density layered insulator for use with a laser is disclosed which provides at least two different insulation materials for a laser discharge tube, where the two insulation materials have different thermoconductivities. The multiple layer insulation materials provide for improved thermoconductivity capability for improved laser operation. 4 figs.

  20. Multiple layer insulation cover

    DOE Patents [OSTI]

    Farrell, James J.; Donohoe, Anthony J.

    1981-11-03

    A multiple layer insulation cover for preventing heat loss in, for example, a greenhouse, is disclosed. The cover is comprised of spaced layers of thin foil covered fabric separated from each other by air spaces. The spacing is accomplished by the inflation of spaced air bladders which are integrally formed in the cover and to which the layers of the cover are secured. The bladders are inflated after the cover has been deployed in its intended use to separate the layers of the foil material. The sizes of the material layers are selected to compensate for sagging across the width of the cover so that the desired spacing is uniformly maintained when the cover has been deployed. The bladders are deflated as the cover is stored thereby expediting the storage process and reducing the amount of storage space required.

  1. Fundamental studies of grain boundary passivation in polycrystalline silicon with application to improved photovoltaic devices. A research report covering work completed from February 1981 to January 1982

    SciTech Connect (OSTI)

    Seager, C.H.; Ginley, D.S.

    1982-09-01

    Grain boundary barrier heights and other properties were measured on a variety of Wacker poly-Si to test the contention of Redfield that as received samples had no potential barriers and that temperature anneals activate the impurities in the boundaries. Our results show that these generalizations are not true and that a variety of barrier behaviors are found. Several of our new analytical techniques for studying grain boundaries and their passivation have been upgraded, including a new cell for Fourier Transform Infrared (FTIR) studies, electrochemical techniques, and a laser scanning apparatus for imaging grain boundaries. Grain boundaries in a variety of samples have been successfully passivated by the use of both the Kaufman ion source and a dc discharge apparatus. 20% improvements in cell efficiencies have been observed in large grained poly-Si cells, and the time of treatment has been drastically reduced.

  2. PIA - Savannah River Remediation Accreditation Boundary (SRR...

    Energy Savers [EERE]

    PIA - Savannah River Nuclear Solution IBARS Srs Site Apps. Accreditation Boundary PIA - WEB Physical Security Major Application Occupational Medical Surveillance System (OMSS) PIA, ...

  3. Compliant layer chucking surface

    DOE Patents [OSTI]

    Blaedel, Kenneth L.; Spence, Paul A.; Thompson, Samuel L.

    2004-12-28

    A method and apparatus are described wherein a thin layer of complaint material is deposited on the surface of a chuck to mitigate the deformation that an entrapped particle might cause in the part, such as a mask or a wafer, that is clamped to the chuck. The harder particle will embed into the softer layer as the clamping pressure is applied. The material composing the thin layer could be a metal or a polymer for vacuum or electrostatic chucks. It may be deposited in various patterns to affect an interrupted surface, such as that of a "pin" chuck, thereby reducing the probability of entrapping a particle.

  4. On the influence of shrub height and expansion on boreal climate...

    Office of Scientific and Technical Information (OSTI)

    Title: On the influence of shrub height and expansion on boreal climate Authors: Bonfils, C ; Phillips, T ; Lawrence, D ; Cameron-Smith, P ; Riley, W ; Subin, Z Publication Date: ...

  5. EIS-0505: Vantage to Pomona Heights 230 kV Transmission Line...

    Energy Savers [EERE]

    BPA's proposed action is to interconnect the proposed transmission line to an existing BPA substation. EIS-0505: Vantage to Pomona Heights 230 kV Transmission Line Project Public ...

  6. Environmental boundaries to energy development

    SciTech Connect (OSTI)

    Trivelpiece, A.W.

    1989-01-01

    Public concern about the environment, health and safety consequences of energy technology has been growing steadily for more than two decades in the United States. This concern forms an important boundary condition as the United States seeks to develop a new National Energy Strategy. Furthermore, the international aspects of the energy/environment interface such as acid rain global climate change and stratospheric ozone depletion are very prominent in US thinking. In fact, the energy systems of the world are becoming more closely coupled environmentally and otherwise. Now where is this coupling more important than that between the industrialized and developing world; the choices made by each will have profound effects on the other. The development of energy technologies compatible with both economic growth and improving and sustaining environmental quality represents a major R D challenge to the US and USSR. Decision about adoption of new technology and R D priorities can be improved by better measurements of how energy sources and uses are changing throughout the world and better methods to project the potential consequences of these decisions. Such projection require understanding relative risks of alternating existing and evolving technologies. All of these R D areas, technology improvement energy system monitoring and projection and comparative risk assessment are the topics of this seminar. Progress in each may be enhanced by collaboration and cooperation between our two countries. 7 refs., 27 figs., 5 tabs.

  7. Structured luminescence conversion layer

    DOE Patents [OSTI]

    Berben, Dirk; Antoniadis, Homer; Jermann, Frank; Krummacher, Benjamin Claus; Von Malm, Norwin; Zachau, Martin

    2012-12-11

    An apparatus device such as a light source is disclosed which has an OLED device and a structured luminescence conversion layer deposited on the substrate or transparent electrode of said OLED device and on the exterior of said OLED device. The structured luminescence conversion layer contains regions such as color-changing and non-color-changing regions with particular shapes arranged in a particular pattern.

  8. Comparison of Cloud Top Height and Optical Depth Histograms from ISCCP,

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

    MISR, and MODIS Comparison of Cloud Top Height and Optical Depth Histograms from ISCCP, MISR, and MODIS Marchand, Roger Pacific Northwest National Laboratory Ackerman, Thomas Pacific Northwest National Laboratory Category: Cloud Properties Joint histograms of Cloud Top Height (CTH) and Optical Depth (OD) derived by the International Satellite Cloud Climatology Project (ISCCP) are being widely used by the climate modeling community in evaluating global climate models. Similar joint histograms

  9. Finite Element Code For 3D-Hydraulic Fracture Propagation Equations (3-layer).

    Energy Science and Technology Software Center (OSTI)

    1992-03-24

    HYFRACP3D is a finite element program for simulation of a pseudo three-dimensional fracture geometries with a two-dimensional planar solution. The model predicts the height, width and winglength over time for a hydraulic fracture propagating in a three-layered system of rocks with variable rock mechanics properties.

  10. Boundary conditions for the subdiffusion equation

    SciTech Connect (OSTI)

    Shkilev, V. P.

    2013-04-15

    The boundary conditions for the subdiffusion equations are formulated using the continuous-time random walk model, as well as several versions of the random walk model on an irregular lattice. It is shown that the boundary conditions for the same equation in different models have different forms, and this difference considerably affects the solutions of this equation.

  11. Excitonic fine-structure splitting in telecom-wavelength InAs/GaAs quantum dots: Statistical distribution and height-dependence

    SciTech Connect (OSTI)

    Goldmann, Elias Barthel, Stefan; Florian, Matthias; Jahnke, Frank; Schuh, Kolja

    2013-12-09

    The variation of the excitonic fine-structure splitting is studied for semiconductor quantum dots under the influence of a strain-reducing layer, utilized to shift the emission wavelength of the excitonic transition into the telecom-wavelength regime of 1.31.5 ?m. By means of a sp{sup 3}s{sup *}-tight-binding model and configuration interaction, we calculate wavelength shifts and fine-structure splittings for various quantum dot geometries. We find the splittings remaining small and even decreasing with strain-reducing layer composition for quantum dots with large height. Combined with an observed increased emission efficiency, the applicability for generation of entanglement photons is persistent.

  12. Gradient zone-boundary control in salt-gradient solar ponds

    DOE Patents [OSTI]

    Hull, J.R.

    1982-09-29

    A method and apparatus for suppressing zone boundary migration in a salt gradient solar pond includes extending perforated membranes across the pond at the boundaries, between the convective and non-convective zones, the perforations being small enough in size to prevent individual turbulence disturbances from penetrating the hole, but being large enough to allow easy molecular diffusion of salt thereby preventing the formation of convective zones in the gradient layer. The total area of the perforations is a sizeable fraction of the membrane area to allow sufficient salt diffusion while preventing turbulent entrainment into the gradient zone.

  13. ARM: ARSCL: cloud base height from first Clothiaux algorithms on Vaisala or Belfort ceilometers, Micropulse lidar, and MMCR

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

    Karen Johnson; Michael Jensen

    ARSCL: cloud base height from first Clothiaux algorithms on Vaisala or Belfort ceilometers, Micropulse lidar, and MMCR

  14. ARM: ARSCL: cloud base height from first Clothiaux algorithms on Vaisala or Belfort ceilometers, Micropulse lidar, and MMCR

    SciTech Connect (OSTI)

    Karen Johnson; Michael Jensen

    1996-11-08

    ARSCL: cloud base height from first Clothiaux algorithms on Vaisala or Belfort ceilometers, Micropulse lidar, and MMCR

  15. Alleviation of fermi-level pinning effect at metal/germanium interface by the insertion of graphene layers

    SciTech Connect (OSTI)

    Baek, Seung-heon Chris; Seo, Yu-Jin; Oh, Joong Gun; Albert Park, Min Gyu; Bong, Jae Hoon; Yoon, Seong Jun; Lee, Seok-Hee, E-mail: seokheelee@ee.kaist.ac.kr [Department of Electrical Engineering, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon 305-701 (Korea, Republic of); Seo, Minsu; Park, Seung-young [Division of Materials Science, Korea Basic Science Institute (KBSI), 169-148 Daehak-ro, Yuseong-gu, Daejeon 305-333 (Korea, Republic of); Park, Byong-Guk [Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon 305-701 (Korea, Republic of)

    2014-08-18

    In this paper, we report the alleviation of the Fermi-level pinning on metal/n-germanium (Ge) contact by the insertion of multiple layers of single-layer graphene (SLG) at the metal/n-Ge interface. A decrease in the Schottky barrier height with an increase in the number of inserted SLG layers was observed, which supports the contention that Fermi-level pinning at metal/n-Ge contact originates from the metal-induced gap states at the metal/n-Ge interface. The modulation of Schottky barrier height by varying the number of inserted SLG layers (m) can bring about the use of Ge as the next-generation complementary metal-oxide-semiconductor material. Furthermore, the inserted SLG layers can be used as the tunnel barrier for spin injection into Ge substrate for spin-based transistors.

  16. Layered electrode for electrochemical cells

    DOE Patents [OSTI]

    Swathirajan, Swathy; Mikhail, Youssef M.

    2001-01-01

    There is provided an electrode structure comprising a current collector sheet and first and second layers of electrode material. Together, the layers improve catalyst utilization and water management.

  17. EMISSION HEIGHT AND TEMPERATURE DISTRIBUTION OF WHITE-LIGHT EMISSION OBSERVED BY HINODE/SOT FROM THE 2012 JANUARY 27 X-CLASS SOLAR FLARE

    SciTech Connect (OSTI)

    Watanabe, Kyoko; Shimizu, Toshifumi [Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Chuo-ku, Sagamihara, Kanagawa 252-5210 (Japan); Masuda, Satoshi [Solar-Terrestrial Environment Laboratory, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601 (Japan); Ichimoto, Kiyoshi [Kwasan and Hida Observatories, Kyoto University, Yamashina, Kyoto 607-8471 (Japan); Ohno, Masanori, E-mail: watanabe.kyoko@isas.jaxa.jp [Department of Physical Sciences, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8516 (Japan)

    2013-10-20

    White-light emissions were observed from an X1.7 class solar flare on 2012 January 27, using three continuum bands (red, green, and blue) of the Solar Optical Telescope on board the Hinode satellite. This event occurred near the solar limb, and so differences in the locations of the various emissions are consistent with differences in heights above the photosphere of the various emission sources. Under this interpretation, our observations are consistent with the white-light emissions occurring at the lowest levels of where the Ca II H emission occurs. Moreover, the centers of the source regions of the red, green, and blue wavelengths of the white-light emissions are significantly displaced from each other, suggesting that those respective emissions are emanating from progressively lower heights in the solar atmosphere. The temperature distribution was also calculated from the white-light data, and we found the lower-layer emission to have a higher temperature. This indicates that high-energy particles penetrated down to near the photosphere, and deposited heat into the ambient lower layers of the atmosphere.

  18. Spatially Resolved Mapping of Electrical Conductivity around Individual Domain (Grain) Boundaries in Graphene

    SciTech Connect (OSTI)

    Li, An-Ping [ORNL; Clark, Kendal W [ORNL; Zhang, Xiaoguang [ORNL; Vlassiouk, Ivan V [ORNL; He, Guowei [Carnegie Mellon University (CMU); Feenstra, Randall [Carnegie Mellon University (CMU)

    2013-01-01

    Graphene films can now be produced on the scale of up to meters. However, all large-scale graphene films contain topological defects that can significantly affect the characteristic transport behaviors of graphene. Here, we spatially map the structures and electronic transport near specific domain and grain boundaries in graphene, and evaluate effects of different types of defect on the electronic conductivity in epitaxial graphene grown on SiC and CVD graphene on Cu subsequently transferred to a SiO2 substrate. We use a combined approach with a multi-probe scanning tunneling potentiometry to investigate both structures and transport at individual grain boundaries and domain boundaries that are defined by coalesced grains, surface steps, and changes in layer thickness. It is found that the substrate step on SiC presents a significant potential barrier for electron transport of epitaxial graphene due to the reduced charge transport from the substrate at the step edges, monolayer-bilayer boundaries exhibit a high resistivity that can change depending on directions of the current across the boundary, and the resistivity of grain boundaries changes with the transition width of the disordered region between two adjacent grains in graphene. The detailed understanding of graphene defects will provide the feedback for controlled engineering of defects in large-scale graphene films.

  19. Layered semiconductor neutron detectors

    DOE Patents [OSTI]

    Mao, Samuel S; Perry, Dale L

    2013-12-10

    Room temperature operating solid state hand held neutron detectors integrate one or more relatively thin layers of a high neutron interaction cross-section element or materials with semiconductor detectors. The high neutron interaction cross-section element (e.g., Gd, B or Li) or materials comprising at least one high neutron interaction cross-section element can be in the form of unstructured layers or micro- or nano-structured arrays. Such architecture provides high efficiency neutron detector devices by capturing substantially more carriers produced from high energy .alpha.-particles or .gamma.-photons generated by neutron interaction.

  20. Property:Building/Boundaries | Open Energy Information

    Open Energy Info (EERE)

    "BuildingBoundaries" Showing 25 pages using this property. (previous 25) (next 25) S Sweden Building 05K0001 + Several buildings + Sweden Building 05K0002 + Part of a building +...

  1. CNEEC - Atomic Layer Deposition Tutorial by Stacey Bent

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

    Atomic Layer Deposition

  2. Boundary Entropy Can Increase Under Bulk RG Flow (Journal Article...

    Office of Scientific and Technical Information (OSTI)

    Boundary Entropy Can Increase Under Bulk RG Flow Citation Details In-Document Search Title: Boundary Entropy Can Increase Under Bulk RG Flow The boundary entropy log(g) of a critical ...

  3. DOE/SC-ARM-14-034 Lower Atmospheric Boundary Layer Experiment

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

    TA Bonin S Mishra JF Newman M Carney DD Turner EP Jacobsen PB Chilson S Wharton CE ... TA Bonin S Mishra JF Newman M Carney DD Turner EP Jacobsen PB Chilson S Wharton CE ...

  4. New method to determine planetary boundary layer depth | U.S...

    Office of Science (SC) Website

    ... Zhanqing Li College of Global Change and Earth System Science, State Laboratory of Earth Surface Process and Resource Ecology, Beijing Normal University, China. zli@atmos.umd.edu ...

  5. Recollimation boundary layers as X-ray sources in young stellar jets

    SciTech Connect (OSTI)

    Gnther, Hans Moritz; Li, Zhi-Yun; Schneider, P. C.

    2014-11-01

    Young stars accrete mass from circumstellar disks and, in many cases, the accretion coincides with a phase of massive outflows, which can be highly collimated. Those jets emit predominantly in the optical and IR wavelength range. However, in several cases, X-ray and UV observations reveal a weak but highly energetic component in those jets. X-rays are observed both from stationary regions close to the star and from knots in the jet several hundred AU from the star. In this article, we show semianalytically that a fast stellar wind that is recollimated by the pressure from a slower, more massive disk wind can have the right properties to power stationary X-ray emission. The size of the shocked regions is compatible with observational constraints. Our calculations support a wind-wind interaction scenario for the high-energy emission near the base of young stellar object jets. For the specific case of DG Tau, a stellar wind with a mass-loss rate of 5 10{sup 10} M {sub ?} yr{sup 1} and a wind speed of 800 km s{sup 1} reproduces the observed X-ray spectrum. We conclude that a stellar wind recollimation shock is a viable scenario to power stationary X-ray emission close to the jet launching point.

  6. Techno-Economic Boundary Analysis of Biological Pathways to Hydrogen...

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

    Techno-Economic Boundary Analysis of Biological Pathways to Hydrogen Production (2009) Techno-Economic Boundary Analysis of Biological Pathways to Hydrogen Production (2009) ...

  7. Science at the interface : grain boundaries in nanocrystalline...

    Office of Scientific and Technical Information (OSTI)

    Science at the interface : grain boundaries in nanocrystalline metals. Citation Details In-Document Search Title: Science at the interface : grain boundaries in nanocrystalline ...

  8. Suppression of Grain Boundaries in Graphene Growth on Superstructured...

    Office of Scientific and Technical Information (OSTI)

    Suppression of Grain Boundaries in Graphene Growth on Superstructured Mn-Cu(111) Surface Title: Suppression of Grain Boundaries in Graphene Growth on Superstructured Mn-Cu(111) ...

  9. Small and Powerful: Pushing the Boundaries of Nano-Magnets |...

    Office of Science (SC) Website

    and Powerful: Pushing the Boundaries of Nano-Magnets Basic Energy Sciences (BES) BES ... Small and Powerful: Pushing the Boundaries of Nano-Magnets Newly discovered particles ...

  10. EA-1973: Kootenai River Restoration at Bonners Ferry, Boundary...

    Energy Savers [EERE]

    73: Kootenai River Restoration at Bonners Ferry, Boundary County, Idaho EA-1973: Kootenai River Restoration at Bonners Ferry, Boundary County, Idaho Summary Bonneville Power...

  11. Iterative solution of Hermite boundary integral equations (Journal...

    Office of Scientific and Technical Information (OSTI)

    Iterative solution of Hermite boundary integral equations Citation Details In-Document Search Title: Iterative solution of Hermite boundary integral equations An efficient ...

  12. Technoeconomic Boundary Analysis of Biological Pathways to Hydrogen...

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

    Technoeconomic Boundary Analysis of Biological Pathways to Hydrogen Production Technoeconomic Boundary Analysis of Biological Pathways to Hydrogen Production Report documenting the ...

  13. Layered seal for turbomachinery

    DOE Patents [OSTI]

    Sarawate, Neelesh Nandkumar; Morgan, Victor John; Weber, David Wayne

    2015-11-20

    The present application provides seal assemblies for reducing leakages between adjacent components of turbomachinery. The seal assemblies may include outer shims, and at least a portion of the outer shims may be substantially impervious. At least one of the outer shims may be configured for sealing engagement with seal slots of the adjacent components. The seal assemblies may also include at least one of an inner shim and a filler layer positioned between the outer shims. The at least one inner shim may be substantially solid and the at least one filler layer may be relatively porous. The seal assemblies may be sufficiently flexible to account for misalignment between the adjacent components, sufficiently stiff to meet assembly requirements, and sufficiently robust to operating meet requirements associated with turbomachinery.

  14. Effect of habitat and foraging height on bat activity in the coastal plain of South Carolina.

    SciTech Connect (OSTI)

    Menzel, Jennifer, M.; Menzel, Michael A.; Kilgo, John C.; Ford, W. Mark; Edwards, John W.; McCracken, Gary F.

    2005-07-01

    A comparison of bat activity levels in the Coastal Plain of South Carolina among 5 habitat types: forested riparian areas, clearcuts, young pine plantations, mature pine plantations and pine savannas, using time expansion radio-microphones and integrated detectors to simultaneously monitor bat activity at three heights in each habitat type.

  15. Surface and grain boundary scattering in nanometric Cu thin films: A quantitative analysis including twin boundaries

    SciTech Connect (OSTI)

    Barmak, Katayun [Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York 10027 and Department of Materials Science and Engineering and Materials Research Science and Engineering Center, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213 (United States); Darbal, Amith [Department of Materials Science and Engineering and Materials Research Science and Engineering Center, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213 (United States); Ganesh, Kameswaran J.; Ferreira, Paulo J. [Materials Science and Engineering, The University of Texas at Austin, 1 University Station, Austin, Texas 78712 (United States); Rickman, Jeffrey M. [Department of Materials Science and Engineering and Department of Physics, Lehigh University, Bethlehem, Pennsylvania 18015 (United States); Sun, Tik; Yao, Bo; Warren, Andrew P.; Coffey, Kevin R., E-mail: kb2612@columbia.edu [Department of Materials Science and Engineering, University of Central Florida, 4000 Central Florida Boulevard, Orlando, Florida 32816 (United States)

    2014-11-01

    The relative contributions of various defects to the measured resistivity in nanocrystalline Cu were investigated, including a quantitative account of twin-boundary scattering. It has been difficult to quantitatively assess the impact twin boundary scattering has on the classical size effect of electrical resistivity, due to limitations in characterizing twin boundaries in nanocrystalline Cu. In this study, crystal orientation maps of nanocrystalline Cu films were obtained via precession-assisted electron diffraction in the transmission electron microscope. These orientation images were used to characterize grain boundaries and to measure the average grain size of a microstructure, with and without considering twin boundaries. The results of these studies indicate that the contribution from grain-boundary scattering is the dominant factor (as compared to surface scattering) leading to enhanced resistivity. The resistivity data can be well-described by the combined FuchsSondheimer surface scattering model and MayadasShatzkes grain-boundary scattering model using Matthiessen's rule with a surface specularity coefficient of p?=?0.48 and a grain-boundary reflection coefficient of R?=?0.26.

  16. ARM - Datastreams - ncepgfsflx

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

    relevant. Measurement Variable Surface albedo albedo Precipitation convprecip Soil heat flux groundhflx Cloud fraction higha Planetary boundary layer height hpbl Latent...

  17. ARM - Datastreams - ncepgfsmanflx

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

    relevant. Measurement Variable Surface albedo albedo Precipitation convprecip Soil heat flux groundhflx Cloud fraction higha Planetary boundary layer height hpbl Latent...

  18. ARM - Datastreams - ncepgfsbrwflx

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

    relevant. Measurement Variable Surface albedo albedo Precipitation convprecip Soil heat flux groundhflx Cloud fraction higha Planetary boundary layer height hpbl Latent...

  19. ARM - Datastreams - ncepgfsatkflx

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

    relevant. Measurement Variable Surface albedo albedo Precipitation convprecip Soil heat flux groundhflx Cloud fraction higha Planetary boundary layer height hpbl Latent...

  20. ARM - Datastreams - ncepgfsnauflx

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

    relevant. Measurement Variable Surface albedo albedo Precipitation convprecip Soil heat flux groundhflx Cloud fraction higha Planetary boundary layer height hpbl Latent...

  1. Wireless boundary monitor system and method

    DOE Patents [OSTI]

    Haynes, H.D.; Ayers, C.W.

    1997-12-09

    A wireless boundary monitor system used to monitor the integrity of a boundary surrounding an area uses at least two housings having at least one transmitting means for emitting ultrasonic pressure waves to a medium. Each of the housings has a plurality of receiving means for sensing the pressure waves in the medium. The transmitting means and the receiving means of each housing are aimable and communicably linked. At least one of the housings is equipped with a local alarm means for emitting a first alarm indication whereby, when the pressure waves propagating from a transmitting means to a receiving means are sufficiently blocked by an object a local alarm means or a remote alarm means or a combination thereof emit respective alarm indications. The system may be reset either manually or automatically. This wireless boundary monitor system has useful applications in both indoor and outdoor environments. 4 figs.

  2. Wireless boundary monitor system and method

    DOE Patents [OSTI]

    Haynes, Howard D.; Ayers, Curtis W.

    1997-01-01

    A wireless boundary monitor system used to monitor the integrity of a boundary surrounding an area uses at least two housings having at least one transmitting means for emitting ultrasonic pressure waves to a medium. Each of the housings has a plurality of receiving means for sensing the pressure waves in the medium. The transmitting means and the receiving means of each housing are aimable and communicably linked. At least one of the housings is equipped with a local alarm means for emitting a first alarm indication whereby, when the pressure waves propagating from a transmitting means to a receiving means are sufficiently blocked by an object a local alarm means or a remote alarm means or a combination thereof emit respective alarm indications. The system may be reset either manually or automatically. This wireless boundary monitor system has useful applications in both indoor and outdoor environments.

  3. Buried oxide layer in silicon

    DOE Patents [OSTI]

    Sadana, Devendra Kumar; Holland, Orin Wayne

    2001-01-01

    A process for forming Silicon-On-Insulator is described incorporating the steps of ion implantation of oxygen into a silicon substrate at elevated temperature, ion implanting oxygen at a temperature below 200.degree. C. at a lower dose to form an amorphous silicon layer, and annealing steps to form a mixture of defective single crystal silicon and polycrystalline silicon or polycrystalline silicon alone and then silicon oxide from the amorphous silicon layer to form a continuous silicon oxide layer below the surface of the silicon substrate to provide an isolated superficial layer of silicon. The invention overcomes the problem of buried isolated islands of silicon oxide forming a discontinuous buried oxide layer.

  4. Metal deposition using seed layers

    DOE Patents [OSTI]

    Feng, Hsein-Ping; Chen, Gang; Bo, Yu; Ren, Zhifeng; Chen, Shuo; Poudel, Bed

    2013-11-12

    Methods of forming a conductive metal layers on substrates are disclosed which employ a seed layer to enhance bonding, especially to smooth, low-roughness or hydrophobic substrates. In one aspect of the invention, the seed layer can be formed by applying nanoparticles onto a surface of the substrate; and the metallization is achieved by electroplating an electrically conducting metal onto the seed layer, whereby the nanoparticles serve as nucleation sites for metal deposition. In another approach, the seed layer can be formed by a self-assembling linker material, such as a sulfur-containing silane material.

  5. Analysis of the Younger Dryas Impact Layer

    SciTech Connect (OSTI)

    Firestone, Richard B.; West, Allen; Revay, Zsolt; Hagstrum, Jonathon T,; Belgya, Thomas; Hee, Shane S. Que; Smith, Alan R.

    2010-02-27

    We have uncovered a thin layer of magnetic grains and microspherules, carbon spherules, and glass-like carbon at nine sites across North America, a site in Belgium, and throughout the rims of 16 Carolina Bays. It is consistent with the ejecta layer from an impact event and has been dated to 12.9 ka BP coinciding with the onset of Younger Dryas (YD) cooling and widespread megafaunal extinctions in North America. At many locations the impact layer is directly below a black mat marking the sudden disappearance of the megafauna and Clovis people. The distribution pattern of the Younger Dryas boundary (YDB) ejecta layer is consistent with an impact near the Great Lakes that deposited terrestrial-like ejecta near the impact site and unusual, titanium-rich projectile-like ejecta further away. High water content associated with the ejecta, up to 28 at. percent hydrogen (H), suggests the impact occurred over the Laurentide Ice Sheet. YDB microspherules and magnetic grains are highly enriched in TiO{sub 2}. Magnetic grains from several sites are enriched in iridium (Ir), up to 117 ppb. The TiO{sub 2}/FeO, K/Th, TiO{sub 2}/Zr, Al{sub 2}O{sub 3}/FeO+MgO, CaO/Al{sub 2}O{sub 3}, REE/ chondrite, FeO/MnO ratios and SiO{sub 2}, Na{sub 2}O, K{sub 2}O, Cr{sub 2}O{sub 3}, Ni, Co, U, Th and other trace element abundances are inconsistent with all terrestrial and extraterrestrial (ET) sources except for KREEP, a lunar igneous rock rich in potassium (K), rare-earth elements (REE), phosphorus (P), and other incompatible elements including U and Th. Normal Fe, Ti, and {sup 238}U/{sup 235}U isotopic abundances were found in the magnetic grains, but {sup 234}U was enriched over equilibrium values by 50 percent in Murray Springs and by 130 percent in Belgium. 40K abundance is enriched by up to 100 percent in YDB sediments and Clovis chert artifacts. Highly vesicular carbon spherules containing nanodiamonds, glass-like carbon, charcoal and soot found in large quantities in the YDB layer are

  6. Chamberlain Heights Redevelopment: A Large Scale, Cold Climate Study of Affordable Housing Retrofits

    SciTech Connect (OSTI)

    Donnelly, K.; Mahle, M.

    2012-03-01

    The City of Meriden Housing Authority (MHA) collaborated with affordable housing developer Jonathon Rose Companies (JRC) to complete a gut renovation of 124 residential units in the Chamberlain Heights retrofit project. The affordable housing community is made up of 36 buildings in duplex and quad configurations located on 22 acres within two miles of downtown Meriden, CT. The final post-retrofit analysis showed 40%-45% source energy savings over the existing pre-retrofit conditions.

  7. Chamberlain Heights Redevelopment: A Large Scale, Cold Climate Study of Affordable Housing Retrofits

    SciTech Connect (OSTI)

    Donnelly, K.; Mahle, M.

    2012-03-01

    The City of Meriden Housing Authority (MHA) collaborated with affordable housing developer Jonathon Rose Companies (JRC) to complete a gut renovation of 124 residential units in the Chamberlain Heights retrofit project. The affordable housing community is made up of 36 buildings in duplex and quad configurations located on 22 acres within two miles of downtown Meriden, CT. The final post-retrofit analysis showed 40-45% source energy savings over the existing pre-retrofit conditions.

  8. Estimating Three-Dimensional Cloudy Radiative Transfer Effects from Time-Height Cross Sections

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

    Estimating Three-Dimensional Cloudy Radiative Transfer Effects from Time-Height Cross Sections C. Hannay and R. Pincus National Oceanic and Atmospheric Administration Climate Diagnostics Center Boulder, Colorado K. F. Evans Program in Atmospheric and Oceanic Sciences University of Colorado Boulder, Colorado Introduction Clouds in the atmosphere are finite in extent and variable in every direction and in time. Long data sets from ground-based profilers, such as lidars or cloud radars, could

  9. Templated, layered manganese phosphate

    DOE Patents [OSTI]

    Thoma, Steven G.; Bonhomme, Francois R.

    2004-08-17

    A new crystalline maganese phosphate composition having an empirical formula: O). The compound was determined to crystallize in the trigonal space group P-3c1 with a=8.8706(4) .ANG., c=26.1580(2) .ANG., and V (volume)=1783 .ANG..sup.3. The structure consists of sheets of corner sharing Mn(II)O.sub.4 and PO.sub.4 tetrahedra with layers of (H.sub.3 NCH.sub.2 CH.sub.2).sub.3 N and water molecules in-between. The pronated (H.sub.3 NCH.sub.2 CH.sub.2).sub.3 N molecules provide charge balancing for the inorganic sheets. A network of hydrogen bonds between water molecules and the inorganic sheets holds the structure together.

  10. Very low Schottky barrier height at carbon nanotube and silicon carbide interface

    SciTech Connect (OSTI)

    Inaba, Masafumi Suzuki, Kazuma; Shibuya, Megumi; Lee, Chih-Yu; Masuda, Yoshiho; Tomatsu, Naoya; Norimatsu, Wataru; Kusunoki, Michiko; Hiraiwa, Atsushi; Kawarada, Hiroshi

    2015-03-23

    Electrical contacts to silicon carbide with low contact resistivity and high current durability are crucial for future SiC power devices, especially miniaturized vertical-type devices. A carbon nanotube (CNT) forest formed by silicon carbide (SiC) decomposition is a densely packed forest, and is ideal for use as a heat-dissipative ohmic contact in SiC power transistors. The contact resistivity and Schottky barrier height in a Ti/CNT/SiC system with various SiC dopant concentrations were evaluated in this study. Contact resistivity was evaluated in relation to contact area. The Schottky barrier height was calculated from the contact resistivity. As a result, the Ti/CNT/SiC contact resistivity at a dopant concentration of 3??10{sup 18?}cm{sup ?3} was estimated to be ?1.3??10{sup ?4} ??cm{sup 2} and the Schottky barrier height of the CNT/SiC contact was in the range of 0.400.45?eV. The resistivity is relatively low for SiC contacts, showing that CNTs have the potential to be a good ohmic contact material for SiC power electronic devices.

  11. Processes for multi-layer devices utilizing layer transfer

    DOE Patents [OSTI]

    Nielson, Gregory N; Sanchez, Carlos Anthony; Tauke-Pedretti, Anna; Kim, Bongsang; Cederberg, Jeffrey; Okandan, Murat; Cruz-Campa, Jose Luis; Resnick, Paul J

    2015-02-03

    A method includes forming a release layer over a donor substrate. A plurality of devices made of a first semiconductor material are formed over the release layer. A first dielectric layer is formed over the plurality of devices such that all exposed surfaces of the plurality of devices are covered by the first dielectric layer. The plurality of devices are chemically attached to a receiving device made of a second semiconductor material different than the first semiconductor material, the receiving device having a receiving substrate attached to a surface of the receiving device opposite the plurality of devices. The release layer is etched to release the donor substrate from the plurality of devices. A second dielectric layer is applied over the plurality of devices and the receiving device to mechanically attach the plurality of devices to the receiving device.

  12. On the interaction of solutes with grain boundaries

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

    Dingreville, Remi Philippe Michel; Berbenni, Stephane

    2015-11-01

    Solute segregation to grain boundaries is considered by modeling solute atoms as misfitting inclusions within a disclination structural unit model describing the grain boundary structure and its intrinsic stress field. The solute distribution around grain boundaries is described through Fermi–Dirac statistics of site occupancy. The susceptibility of hydrogen segregation to symmetric tilt grain boundaries is discussed in terms of the misorientation angle, the defect type characteristics at the grain boundary, temperature, and the prescribed bulk hydrogen fraction of occupied sites. Through this formalism, it is found that hydrogen trapping on grain boundaries clearly correlates with the grain boundary structure (i.e.more » type of structural unit composing the grain boundary), and the associated grain boundary misorientation. Specifically, for symmetric tilt grain boundaries about the [001] axis, grain boundaries composed of both B and C structural units show a lower segregation susceptibility than other grain boundaries. A direct correlation between the segregation susceptibility and the intrinsic net defect density is provided through the Frank–Bilby formalism. Moreover, the present formulation could prove to be a simple and useful model to identify classes of grain boundaries relevant to grain boundary engineering.« less

  13. On the interaction of solutes with grain boundaries

    SciTech Connect (OSTI)

    Dingreville, Remi Philippe Michel; Berbenni, Stephane

    2015-11-01

    Solute segregation to grain boundaries is considered by modeling solute atoms as misfitting inclusions within a disclination structural unit model describing the grain boundary structure and its intrinsic stress field. The solute distribution around grain boundaries is described through Fermi–Dirac statistics of site occupancy. The susceptibility of hydrogen segregation to symmetric tilt grain boundaries is discussed in terms of the misorientation angle, the defect type characteristics at the grain boundary, temperature, and the prescribed bulk hydrogen fraction of occupied sites. Through this formalism, it is found that hydrogen trapping on grain boundaries clearly correlates with the grain boundary structure (i.e. type of structural unit composing the grain boundary), and the associated grain boundary misorientation. Specifically, for symmetric tilt grain boundaries about the [001] axis, grain boundaries composed of both B and C structural units show a lower segregation susceptibility than other grain boundaries. A direct correlation between the segregation susceptibility and the intrinsic net defect density is provided through the Frank–Bilby formalism. Moreover, the present formulation could prove to be a simple and useful model to identify classes of grain boundaries relevant to grain boundary engineering.

  14. Spherules from the Cretaceous/Tertiary boundary clay at Gubbio, Italy: the problem of outcrop contamination

    SciTech Connect (OSTI)

    Montanari, A.

    1986-12-01

    Surficial outcrop contamination has occurred in some well-known stratigraphic sections of carbonate rocks in the northern Apennines. A critical case involves several contaminated clay partings, including the Cretaceous/Tertiary boundary clay in the classic Bottaccione section near Gubbio, Italy. These clay layers contain shiny spherules which, in several recent studies, have been said to consist of volcanic glass and have been used to support the hypothesis that the terminal Cretaceous mass extinction was caused by widespread volcanism. Laboratory tests, however, indicate that these shiny spherules are made of HF-insoluble and combustible material and are therefore of recent biological origin. These objects were introduced into the Cretaceous/Tertiary boundary clay and other clay layers from the surrounding soil along with abundant detrital contaminants derived from erosion of the middle Miocene flysch exposed at the head of the Bottaccione Gorge. They are completely different from the altered and flattened microtektitelike spheroids that are found only in the iridium-rich Cretaceous/Tertiary boundary clay and that provide strong evidence for a large impact.

  15. Evidence of preferential diffusion of impurities along grain boundaries in very pure niobium used for radio frequency cavities

    SciTech Connect (OSTI)

    Antoine, C.; Bonin, B.; Safa, H.

    1997-02-01

    In order to overcome dissipation due to impurity segregation at grain boundaries, niobium cavities are submitted to a purification annealing (1300{degree}C{plus_minus}200{degree}C under vacuum) during which titanium is evaporated onto the Nb surface. The resulting titanium layer acts as a solid state getter reacting with light impurities (H, C, N, O), thereby removing these impurities from the bulk of the niobium. Preferential titanium diffusion along grain boundaries have been studied using proton-induced x-ray emission. {copyright} {ital 1997 American Institute of Physics.}

  16. The relationship between grain boundary structure, defect mobility, and grain boundary sink efficiency

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

    Uberuaga, Blas Pedro; Vernon, Louis J.; Martinez, Enrique; Voter, Arthur F.

    2015-03-13

    Nanocrystalline materials have received great attention due to their potential for improved functionality and have been proposed for extreme environments where the interfaces are expected to promote radiation tolerance. However, the precise role of the interfaces in modifying defect behavior is unclear. Using long-time simulations methods, we determine the mobility of defects and defect clusters at grain boundaries in Cu. We find that mobilities vary significantly with boundary structure and cluster size, with larger clusters exhibiting reduced mobility, and that interface sink efficiency depends on the kinetics of defects within the interface via the in-boundary annihilation rate of defects. Thus,more » sink efficiency is a strong function of defect mobility, which depends on boundary structure, a property that evolves with time. Further, defect mobility at boundaries can be slower than in the bulk, which has general implications for the properties of polycrystalline materials. Finally, we correlate defect energetics with the volumes of atomic sites at the boundary.« less

  17. Open Boundary Conditions for Dissipative MHD

    SciTech Connect (OSTI)

    Meier, E T

    2011-11-10

    In modeling magnetic confinement, astrophysics, and plasma propulsion, representing the entire physical domain is often difficult or impossible, and artificial, or 'open' boundaries are appropriate. A novel open boundary condition (BC) for dissipative MHD, called Lacuna-based open BC (LOBC), is presented. LOBC, based on the idea of lacuna-based truncation originally presented by V.S. Ryaben'kii and S.V. Tsynkov, provide truncation with low numerical noise and minimal reflections. For hyperbolic systems, characteristic-based BC (CBC) exist for separating the solution into outgoing and incoming parts. In the hyperbolic-parabolic dissipative MHD system, such separation is not possible, and CBC are numerically unstable. LOBC are applied in dissipative MHD test problems including a translating FRC, and coaxial-electrode plasma acceleration. Solution quality is compared to solutions using CBC and zero-normal derivative BC. LOBC are a promising new open BC option for dissipative MHD.

  18. Oxygen-reducing catalyst layer

    DOE Patents [OSTI]

    O'Brien, Dennis P.; Schmoeckel, Alison K.; Vernstrom, George D.; Atanasoski, Radoslav; Wood, Thomas E.; Yang, Ruizhi; Easton, E. Bradley; Dahn, Jeffrey R.; O'Neill, David G.

    2011-03-22

    An oxygen-reducing catalyst layer, and a method of making the oxygen-reducing catalyst layer, where the oxygen-reducing catalyst layer includes a catalytic material film disposed on a substrate with the use of physical vapor deposition and thermal treatment. The catalytic material film includes a transition metal that is substantially free of platinum. At least one of the physical vapor deposition and the thermal treatment is performed in a processing environment comprising a nitrogen-containing gas.

  19. Segregation and Migration of the Oxygen Vacancies in the 3 (111) Tilt Grain Boundaries of Ceria

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

    Yuan, Fenglin; Liu, Bin; Zhang, Yanwen; Weber, William J.

    2016-03-01

    In nanocrystalline materials, defect-grain boundary (GB) interaction plays a key role in determining the structure stability, as well as size-dependent ionic, electronic, magnetic and chemical properties. In this study, we systematically investigated using density functional theory segregation and migration of oxygen vacancies at the Σ3 [110] / (111) grain boundary of ceria. Three oxygen layers near the GB are predicted to be segregation sites for oxygen vacancies. Moreover, the presence of oxygen vacancies stabilizes this tilt GB at a low Fermi level and/or oxygen poor conditions. An atomic strain model was proposed to rationalize layer dependency of the relaxation energymore » for +2 charged oxygen vacancy. The structural origin of large relaxation energies at layers 1 and 2 was determined to be free-volume space that induces ion relaxation towards the GB. Our results not only pave the way for improving the oxygen transport near GBs of ceria, but also provide important insights into engineering the GB structure for better ionic, magnetic and chemical properties of nanocrystalline ceria.« less

  20. Layer-by-Layer Assembly of Enzymes on Carbon Nanotubes

    SciTech Connect (OSTI)

    Wang, Jun; Liu, Guodong; Lin, Yuehe

    2008-06-01

    The use of Layer-by-layer techniques for immobilizing several types of enzymes, e.g. glucose oxidase (GOx), horse radish oxidases(HRP), and choline oxidase(CHO) on carbon nanotubes and their applications for biosenseing are presented. The enzyme is immobilized on the negatively charged CNT surface by alternatively assembling a cationic polydiallyldimethyl-ammonium chloride (PDDA) layer and a enzyme layer. The sandwich-like layer structure (PDDA/enzyme/PDDA/CNT) formed by electrostatic assembling provides a favorable microenvironment to keep the bioactivity of enzyme and to prevent enzyme molecule leakage. The morphologies and electrocatalytic acitivity of the resulted enzyme film were characterized using TEM and electrochemical techniques, respectively. It was found that these enzyme-based biosensors are very sensitive, selective for detection of biomolecules, e.g. glucose, choline.

  1. Leakage pathway layer for solar cell

    SciTech Connect (OSTI)

    Luan, Andy; Smith, David; Cousins, Peter; Sun, Sheng

    2015-12-01

    Leakage pathway layers for solar cells and methods of forming leakage pathway layers for solar cells are described.

  2. Boundary Entropy Can Increase Under Bulk RG Flow (Journal Article...

    Office of Scientific and Technical Information (OSTI)

    Boundary Entropy Can Increase Under Bulk RG Flow Citation Details In-Document Search Title: Boundary Entropy Can Increase Under Bulk RG Flow You are accessing a document from ...

  3. Evolution of Grain Boundary Networks in Extreme Radiation Environments

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

    of the Evolution of Grain Boundary Networks in Extreme Radiation Environments. Evolution of Grain Boundary Networks in Extreme Radiation Environments Research Our objective is to understand the characteristics of an "optimal" grain boundary (GB) network that minimizes microstructural evolution in radiation environments. Through our research we have elucidated that this optimal network requires a balance between two populations of grain boundaries: low free volume (low free energy)

  4. Technoeconomic Boundary Analysis of Biological Pathways to Hydrogen

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

    Production | Department of Energy Boundary Analysis of Biological Pathways to Hydrogen Production Technoeconomic Boundary Analysis of Biological Pathways to Hydrogen Production Report documenting the biological and engineering characteristics of five algal and bacterial hydrogen production systems selected by DOE and NREL for evaluation. Technoeconomic Boundary Analysis of Biological Pathways to Hydrogen Production (3.63 MB) More Documents & Publications Techno-Economic Boundary Analysis

  5. Method of deforming a biaxially textured buffer layer on a textured metallic substrate and articles therefrom

    DOE Patents [OSTI]

    Lee, Dominic F.; Kroeger, Donald M.; Goyal, Amit

    2000-01-01

    The present invention provides methods and biaxially textured articles having a deformed epitaxial layer formed therefrom for use with high temperature superconductors, photovoltaic, ferroelectric, or optical devices. A buffer layer is epitaxially deposited onto biaxially-textured substrates and then mechanically deformed. The deformation process minimizes or eliminates grooves, or other irregularities, formed on the buffer layer while maintaining the biaxial texture of the buffer layer. Advantageously, the biaxial texture of the buffer layer is not altered during subsequent heat treatments of the deformed buffer. The present invention provides mechanical densification procedures which can be incorporated into the processing of superconducting films through the powder deposit or precursor approaches without incurring unfavorable high-angle grain boundaries.

  6. GRAIN BOUNDARY STRENGTHENING PROPERTIES OF TUNGSTEN ALLOYS

    SciTech Connect (OSTI)

    Setyawan, Wahyu; Kurtz, Richard J.

    2012-10-10

    Density functional theory was employed to investigate grain boundary (GB) properties of W alloys. A range of substitutional solutes across the Periodic Table was investigated to understand the behavior of different electronic orbitals in changing the GB cleavage energy in the Σ27a[110]{525} GB. A number of transition metals were predicted to enhance the GB cohesion. This includes Ru, Re, Os, Ir, V, Cr, Mn, Fe, Co, Ti, Hf, Ta and Nb. While lanthanides, s and p elements were tended to cause GB embrittlement.

  7. Fabrication of Emissible Metallic Layer-by-Layer Photonic Crystals...

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

    polymer is coated on the first polymer. A substrate or a multi-layer polymer structure is placed on the filled mold and the resulting structure is exposed to UV light (i.e., is UV...

  8. D0 layer 0 innermost layer of silicon microstrip tracker

    SciTech Connect (OSTI)

    Hanagaki, K.; /Fermilab

    2006-01-01

    A new inner layer silicon strip detector has been built and will be installed in the existing silicon microstrip tracker in D0. They report on the motivation, design, and performance of this new detector.

  9. Direct imaging of enhanced current collection on grain boundaries of Cu(In,Ga)Se{sub 2} solar cells

    SciTech Connect (OSTI)

    Kim, JunHo; Kim, SeongYeon; Jiang, Chun-Sheng; Ramanathan, Kannan; Al-Jassim, Mowafak M.

    2014-02-10

    We report on direct imaging of current collection by performing conductive atomic force microscopy (C-AFM) measurement on a complete Cu(In,Ga)Se{sub 2} solar cell. The localized current was imaged by milling away the top conductive layer of the device by repeated C-AFM scans. The result exhibits enhanced photocurrent collection on grain boundaries (GBs) of CIGS films, consistent with the argument for electric-field-assisted carrier collection on the GBs.

  10. A Characteristic-Galerkin method for the Navier-Stokes equations in thin domains with free boundaries

    SciTech Connect (OSTI)

    Cornetti, G.M.

    1995-12-31

    The 3D Navier-Stokes equations are solved via the Characteristic-Galerkin method extended to free boundary problems. A temporal discretization procedure is proposed for the case where a preferential direction to move mesh point exists, as in thin domains. Using a single layer of finite elements, the numerical results cover the so-called shallow water 2D approximation, showing the same wave propagation speed.

  11. APIVT-Grown Silicon Thin Layers and PV Devices: Preprint

    SciTech Connect (OSTI)

    Wang, T. H.; Ciszek, T. F.; Page, M. R.; Bauer, R. E.; Wang, Q.; Landry, M. D.

    2002-05-01

    Large-grained (5-20 ..mu..m) polycrystalline silicon layers have been grown at intermediate temperatures of 750-950C directly on foreign substrates without a seeding layer by iodine vapor transport at atmospheric pressure with rates as high as 3 mm/min. A model is constructed to explain the atypical temperature dependence of growth rate. We have also used this technique to grow high-quality epitaxial layers on heavily doped CZ-Si and on upgraded MG-Si substrates. Possible solar cell structures of thin-layer polycrystalline silicon on foreign substrates with light trapping have been examined, compared, and optimized by two-dimensional device simulations. The effects of grain boundary re-combination on device performance are presented for two grain sizes of 2 and 20 mm. We found that 104 cm/s recombination velocity is adequate for 20-m m grain-sized thin silicon, whereas a very low recombination velocity of 103 cm/s must be accomplished in order to achieve reasonable performance for a 2- mm grain-sized polycrystalline silicon device.

  12. Thickness determination of few-layer hexagonal boron nitride films by scanning electron microscopy and Auger electron spectroscopy

    SciTech Connect (OSTI)

    Sutter, P. Sutter, E.

    2014-09-01

    We assess scanning electron microscopy (SEM) and Auger electron spectroscopy (AES) for thickness measurements on few-layer hexagonal boron nitride (h-BN), the layered dielectric of choice for integration with graphene and other two-dimensional materials. Observations on h-BN islands with large, atomically flat terraces show that the secondary electron intensity in SEM reflects monolayer height changes in films up to least 10 atomic layers thickness. From a quantitative analysis of AES data, the energy-dependent electron escape depth in h-BN films is deduced. The results show that AES is suitable for absolute thickness measurements of few-layer h-BN of 1 to 6 layers.

  13. Proposed Route to Thin Film Crystal Si Using Biaxially Textured Foreign Template Layers

    SciTech Connect (OSTI)

    Teplin, C. W.; Ginley, D. S.; van Hest, M.F.A.M.; Perkins, J. D.; Young, D. L.; Stradins, P.; Wang, Q.; Al-Jassim, M.; Iwaniczko, E.; Leenheer, A.; Jones, K. M.; Branz, H. M.

    2005-11-01

    We have developed a new approach to growing photovoltaic-quality crystal silicon (c-Si) films on glass. Other approaches to film c-Si focus on increasing grain size in order to reduce the deleterious effects of grain boundaries. Instead, we have developed an approach to align the silicon grains biaxially (both in and out of plane) so that 1) grain boundaries are "low-angle" and have less effect on the electronic properties of the material and 2) subsequent epitaxial thickening is simplified. They key to our approach is the use of a foreign template layer that can be grown with biaxial texture directly on glass.

  14. Intermetallic Layers in Soldered Joints

    Energy Science and Technology Software Center (OSTI)

    1998-12-10

    ILAG solves the one-dimensional partial differential equations describing the multiphase, multicomponent, solid-state diffusion-controlled growth of intermetallic layers in soldered joints. This software provides an analysis capability for materials researchers to examine intermetallic growth mechanisms in a wide variety of defense and commercial applications involving both traditional and advanced materials. ILAG calculates the interface positions of the layers, as well as the spatial distribution of constituent mass fractions, and outputs the results at user-prescribed simulation times.

  15. Influences and interactions of inundation, peat, and snow on active layer thickness

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

    Atchley, Adam L.; Coon, Ethan T.; Painter, Scott L.; Harp, Dylan R.; Wilson, Cathy J.

    2016-05-18

    The effect of three environmental conditions: 1) thickness of organic soil, 2) snow depth, and 3) soil moisture content or water table height above and below the soil surface, on active layer thickness (ALT) are investigated using an ensemble of 1D thermal hydrology models. Sensitivity analyses of the ensemble exposed the isolated influence of each environmental condition on ALT and their multivariate interactions. The primary and interactive influences are illustrated in the form of color maps of ALT change. Results show that organic layer acts as a strong insulator, and its thickness is the dominant control of ALT, but themore » strength of the effect of organic layer thickness is dependent on the saturation state. Snow depth, subsurface saturation, and ponded water depth are strongly codependent and positively correlated to ALT.« less

  16. Influences of Peat, Surface and Subsurface Water, and Snow on Active Layer Thickness

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

    Atchley, Adam; Coon, Ethan T.; Painter, Scott L; Harp, Dylan; Wilson, Cathy

    2016-01-01

    The effect of three environmental conditions: 1) thickness of organic soil, 2) snow depth, and 3) soil moisture content or water table height above and below the soil surface, on active layer thickness (ALT) are investigated using an ensemble of 1D thermal hydrology models. Sensitivity analyses of the ensemble exposed the isolated influence of each environmental condition on ALT and their multivariate interactions. The primary and interactive influences are illustrated in the form of color maps of ALT change. Results show that organic layer acts as a strong insulator, and its thickness is the dominant control of ALT, but themore » strength of the effect of organic layer thickness is dependent on the saturation state. Snow depth, subsurface saturation, and ponded water depth are strongly codependent and positively correlated to ALT.« less

  17. Hybrid window layer for photovoltaic cells

    DOE Patents [OSTI]

    Deng, Xunming

    2010-02-23

    A novel photovoltaic solar cell and method of making the same are disclosed. The solar cell includes: at least one absorber layer which could either be a lightly doped layer or an undoped layer, and at least a doped window-layers which comprise at least two sub-window-layers. The first sub-window-layer, which is next to the absorber-layer, is deposited to form desirable junction with the absorber-layer. The second sub-window-layer, which is next to the first sub-window-layer, but not in direct contact with the absorber-layer, is deposited in order to have transmission higher than the first-sub-window-layer.

  18. Hybrid window layer for photovoltaic cells

    DOE Patents [OSTI]

    Deng, Xunming; Liao, Xianbo; Du, Wenhui

    2011-10-04

    A novel photovoltaic solar cell and method of making the same are disclosed. The solar cell includes: at least one absorber layer which could either be a lightly doped layer or an undoped layer, and at least a doped window-layers which comprise at least two sub-window-layers. The first sub-window-layer, which is next to the absorber-layer, is deposited to form desirable junction with the absorber-layer. The second sub-window-layer, which is next to the first sub-window-layer, but not in direct contact with the absorber-layer, is deposited in order to have transmission higher than the first-sub-window-layer.

  19. Hybrid window layer for photovoltaic cells

    DOE Patents [OSTI]

    Deng, Xunming; Liao, Xianbo; Du, Wenhui

    2011-02-01

    A novel photovoltaic solar cell and method of making the same are disclosed. The solar cell includes: at least one absorber layer which could either be a lightly doped layer or an undoped layer, and at least a doped window-layers which comprise at least two sub-window-layers. The first sub-window-layer, which is next to the absorber-layer, is deposited to form desirable junction with the absorber-layer. The second sub-window-layer, which is next to the first sub-window-layer, but not in direct contact with the absorber-layer, is deposited in order to have transmission higher than the first-sub-window-layer.

  20. Iridium profile for 10 million years across the Cretaceous-Tertiary boundary at Gubbio (Italy)

    SciTech Connect (OSTI)

    Alvarez, W.; Montanari, A. ); Asaro, F. )

    1990-12-21

    The iridium anomaly at the Cretaceous-Tertiary (KT) boundary was discovered in the pelagic limestone sequence at Gubbio on the basis of 12 samples analyzed by neutron activation analysis (NAA) and was interpreted as indicating impact of a large extraterrestrial object at exactly the time of the KT mass extinction. Continuing controversy over the shape of the Ir profile at the Gubbio KT boundary and its interpretation called for a more detailed follow-up study. Analysis of a 57-meter-thick, 10-million-year-old part of the Gubbio sequence using improved NAA techniques revealed that there is only one Ir anomaly at the KT boundary, but this anomaly shows an intricate fine structure, the origin of which cannot yet be entirely explained. The KT Ir anomaly peaks in a 1-centimeter-thick clay layer, where the average Ir concentration is 3,000 parts per trillion (ppt); this peak is flanked by tails with Ir concentrations of 20 to 80 ppt that rise above a background of 12 to 13 ppt. The fine structure of the tails is probably due in part to lateral reworking, diffusion, burrowing, and perhaps Milankovitch cyclicity.

  1. Atomistic simulations of dislocation pileup: Grain boundaries interaction

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

    Wang, Jian

    2015-05-27

    Here, using molecular dynamics (MD) simulations, we studied the dislocation pileup–grain boundary (GB) interactions. Two Σ11 asymmetrical tilt grain boundaries in Al are studied to explore the influence of orientation relationship and interface structure on dislocation activities at grain boundaries. To mimic the reality of a dislocation pileup in a coarse-grained polycrystalline, we optimized the dislocation population in MD simulations and developed a predict-correct method to create a dislocation pileup in MD simulations. MD simulations explored several kinetic processes of dislocations–GB reactions: grain boundary sliding, grain boundary migration, slip transmission, dislocation reflection, reconstruction of grain boundary, and the correlation ofmore » these kinetic processes with the available slip systems across the GB and atomic structures of the GB.« less

  2. Atomistic simulations of dislocation pileup: Grain boundaries interaction

    SciTech Connect (OSTI)

    Wang, Jian

    2015-05-27

    Here, using molecular dynamics (MD) simulations, we studied the dislocation pileup–grain boundary (GB) interactions. Two Σ11 asymmetrical tilt grain boundaries in Al are studied to explore the influence of orientation relationship and interface structure on dislocation activities at grain boundaries. To mimic the reality of a dislocation pileup in a coarse-grained polycrystalline, we optimized the dislocation population in MD simulations and developed a predict-correct method to create a dislocation pileup in MD simulations. MD simulations explored several kinetic processes of dislocations–GB reactions: grain boundary sliding, grain boundary migration, slip transmission, dislocation reflection, reconstruction of grain boundary, and the correlation of these kinetic processes with the available slip systems across the GB and atomic structures of the GB.

  3. Genetic analysis of inflorescence and plant height components in sorghum (Panicoidae) and comparative genetics with rice (Oryzoidae)

    SciTech Connect (OSTI)

    Zhang, Dong; Kong, Wenqian; Robertson, Jon; Goff, Valorie H; Epps, Ethan; Kerr, Alexandra; Mills, Gabriel; Cromwell, Jay; Lugin, Yelena; Phillips, Christine; Paterson, Andrew H

    2015-12-01

    Domestication has played an important role in shaping characteristics of the inflorescence and plant height in cultivated cereals. Taking advantage of meta-analysis of QTLs, phylogenetic analyses in 502 diverse sorghum accessions, GWAS in a sorghum association panel (n = 354) and comparative data, we provide insight into the genetic basis of the domestication traits in sorghum and rice. We performed genome-wide association studies (GWAS) on 6 traits related to inflorescence morphology and 6 traits related to plant height in sorghum, comparing the genomic regions implicated in these traits by GWAS and QTL mapping, respectively. In a search for signatures of selection, we identify genomic regions that may contribute to sorghum domestication regarding plant height, flowering time and pericarp color. Comparative studies across taxa show functionally conserved ‘hotspots’ in sorghum and rice for awn presence and pericarp color that do not appear to reflect corresponding single genes but may indicate co-regulated clusters of genes. We also reveal homoeologous regions retaining similar functions for plant height and flowering time since genome duplication an estimated 70 million years ago or more in a common ancestor of cereals. In most such homoeologous QTL pairs, only one QTL interval exhibits strong selection signals in modern sorghum. Intersections among QTL, GWAS and comparative data advance knowledge of genetic determinants of inflorescence and plant height components in sorghum, and add new dimensions to comparisons between sorghum and rice.

  4. Genetic analysis of inflorescence and plant height components in sorghum (Panicoidae) and comparative genetics with rice (Oryzoidae)

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

    Zhang, Dong; Kong, Wenqian; Robertson, Jon; Goff, Valorie H; Epps, Ethan; Kerr, Alexandra; Mills, Gabriel; Cromwell, Jay; Lugin, Yelena; Phillips, Christine; et al

    2015-12-01

    Domestication has played an important role in shaping characteristics of the inflorescence and plant height in cultivated cereals. Taking advantage of meta-analysis of QTLs, phylogenetic analyses in 502 diverse sorghum accessions, GWAS in a sorghum association panel (n = 354) and comparative data, we provide insight into the genetic basis of the domestication traits in sorghum and rice. We performed genome-wide association studies (GWAS) on 6 traits related to inflorescence morphology and 6 traits related to plant height in sorghum, comparing the genomic regions implicated in these traits by GWAS and QTL mapping, respectively. In a search for signatures ofmore » selection, we identify genomic regions that may contribute to sorghum domestication regarding plant height, flowering time and pericarp color. Comparative studies across taxa show functionally conserved ‘hotspots’ in sorghum and rice for awn presence and pericarp color that do not appear to reflect corresponding single genes but may indicate co-regulated clusters of genes. We also reveal homoeologous regions retaining similar functions for plant height and flowering time since genome duplication an estimated 70 million years ago or more in a common ancestor of cereals. In most such homoeologous QTL pairs, only one QTL interval exhibits strong selection signals in modern sorghum. Intersections among QTL, GWAS and comparative data advance knowledge of genetic determinants of inflorescence and plant height components in sorghum, and add new dimensions to comparisons between sorghum and rice.« less

  5. Genetic analysis of inflorescence and plant height components in sorghum (Panicoidae) and comparative genetics with rice (Oryzoidae)

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

    Zhang, Dong; Kong, Wenqian; Robertson, Jon; Goff, Valorie H.; Epps, Ethan; Kerr, Alexandra; Mills, Gabriel; Cromwell, Jay; Lugin, Yelena; Phillips, Christine; et al

    2015-04-19

    Domestication has played an important role in shaping characteristics of the inflorescence and plant height in cultivated cereals. Taking advantage of meta-analysis of QTLs, phylogenetic analyses in 502 diverse sorghum accessions, GWAS in a sorghum association panel (n = 354) and comparative data, we provide insight into the genetic basis of the domestication traits in sorghum and rice. We performed genome-wide association studies (GWAS) on 6 traits related to inflorescence morphology and 6 traits related to plant height in sorghum, comparing the genomic regions implicated in these traits by GWAS and QTL mapping, respectively. In a search for signatures ofmoreselection, we identify genomic regions that may contribute to sorghum domestication regarding plant height, flowering time and pericarp color. Comparative studies across taxa show functionally conserved hotspots in sorghum and rice for awn presence and pericarp color that do not appear to reflect corresponding single genes but may indicate co-regulated clusters of genes. We also reveal homoeologous regions retaining similar functions for plant height and flowering time since genome duplication an estimated 70 million years ago or more in a common ancestor of cereals. In most such homoeologous QTL pairs, only one QTL interval exhibits strong selection signals in modern sorghum. Intersections among QTL, GWAS and comparative data advance knowledge of genetic determinants of inflorescence and plant height components in sorghum, and add new dimensions to comparisons between sorghum and rice.less

  6. Absorbing boundary conditions for relativistic quantum mechanics equations

    SciTech Connect (OSTI)

    Antoine, X.; Sater, J.; Fillion-Gourdeau, F.; Bandrauk, A.D.

    2014-11-15

    This paper is devoted to the derivation of absorbing boundary conditions for the Klein–Gordon and Dirac equations modeling quantum and relativistic particles subject to classical electromagnetic fields. Microlocal analysis is the main ingredient in the derivation of these boundary conditions, which are obtained in the form of pseudo-differential equations. Basic numerical schemes are derived and analyzed to illustrate the accuracy of the derived boundary conditions.

  7. Mineral Deformation at Earth's Core-Mantle Boundary

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

    Mineral Deformation at Earth's Core-Mantle Boundary Mineral Deformation at Earth's Core-Mantle Boundary Print Wednesday, 31 August 2011 00:00 Earth is a dynamic planet in which convection takes place on the scale of thousands of kilometers. Because Earth is mostly solid (except for its liquid-iron outer core), this convection causes deformation of solid rocks by plastic flow. At the core-mantle boundary (CMB), 2900 km deep, seismologists have discovered that seismic waves travel faster in

  8. Grain boundary energy in 5 degrees of freedom space

    Energy Science and Technology Software Center (OSTI)

    2012-09-21

    GB5DOF is a program written in MatLab for computing excess energy of an arbitrary grain boundary defined by its 5 geometrical degrees of freedom. The program is written in the form of a single self-contained function callable from within commercially available MatLab software package. The function takes a geometric description of the boundary and material identity as input parameters and returns the predicted boundary energy.

  9. Dynamics of multiple double layers in high pressure glow discharge in a simple torus

    SciTech Connect (OSTI)

    Kumar Paul, Manash, E-mail: manashkr@gmail.com [Department of Physics, National Institute of Technology Agartala, Tripura799 046 (India); Sharma, P. K.; Thakur, A.; Kulkarni, S. V.; Bora, D. [Institute for Plasma Research, Bhat, Gandhinagar, Gujarat382 428 (India)

    2014-06-15

    Parametric characterization of multiple double layers is done during high pressure glow discharge in a toroidal vessel of small aspect ratio. Although glow discharge (without magnetic field) is known to be independent of device geometry, but the toroidal boundary conditions are conducive to plasma growth and eventually the plasma occupy the toroidal volume partially. At higher anode potential, the visibly glowing spots on the body of spatially extended anode transform into multiple intensely luminous spherical plasma blob structures attached to the tip of the positive electrode. Dynamics of multiple double layers are observed in argon glow discharge plasma in presence of toroidal magnetic field. The radial profiles of plasma parameters measured at various toroidal locations show signatures of double layer formation in our system. Parametric dependence of double layer dynamics in presence of toroidal magnetic field is presented here.

  10. Boundary condition and fuel composition effects on injection...

    Office of Scientific and Technical Information (OSTI)

    Publisher's Accepted Manuscript: Boundary condition and fuel composition effects on injection processes of high-pressure sprays at the microscopic level This content will become ...

  11. Evaluation of Wall Boundary Condition Parameters for Gas-Solids

    Office of Scientific and Technical Information (OSTI)

    ... constitutive relations for antigranulocytes-materials, with application to plane shearing. ... Study of wall boundary condition in numerical simulations of 2D bubbling fluidized beds. ...

  12. Mineral Deformation at Earth's Core-Mantle Boundary

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

    core-mantle boundary (CMB), 2900 km deep, seismologists have discovered that seismic waves travel faster in certain directions. This seismic anisotropy appears to be related to...

  13. Mineral Deformation at Earth's Core-Mantle Boundary

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

    parallel to the boundary, which is just what seismologists observe. These results open new possibilities for modeling anisotropy evolution at extreme conditions, linking...

  14. Two-dimensional heavy fermions on the strongly correlated boundaries...

    Office of Scientific and Technical Information (OSTI)

    Two-dimensional heavy fermions on the strongly correlated boundaries of Kondo topological insulators Prev Next Title: Two-dimensional heavy fermions on the strongly ...

  15. [Perovskite and Fluorite Grain Boundary Properties]. Final Project Report

    SciTech Connect (OSTI)

    Browning, N. D.

    2004-02-24

    One of the main areas of research in the last two years in this program has been the properties of grain boundaries in perovskite and fluorite structure materials.

  16. On the interaction of solutes with grain boundaries (Journal...

    Office of Scientific and Technical Information (OSTI)

    is considered by modeling solute atoms as misfitting inclusions within a disclination structural unit model describing the grain boundary structure and its intrinsic stress field. ...

  17. Conditions for establishing quasistable double layers in the Earth's auroral upward current region

    SciTech Connect (OSTI)

    Main, D. S.; Newman, D. L.; Ergun, R. E.

    2010-12-15

    The strength and stability of simulated double layers at the ionosphere-auroral cavity boundary have been studied as a function of cold ionospheric electron temperature and density. The simulations are performed with an open boundary one-dimensional particle-in- cell (PIC) simulation and are initialized by imposing a density cavity within the simulation domain. The PIC simulation includes H{sup +} and O{sup +} ion beams, a hot H{sup +} background population, cold ionospheric electrons, and a hot electron population. It is shown that a double layer remains quasistable for a variety of initial conditions and plasma parameters. The average potential drop of the double layer is found to increase as the cold electron temperature decreases. However, in terms of cold electron density, the average potential drop of the double layer is found to increase up to some critical cold electron density and decreases above this value. Comparisons with FAST observations are made and agreement is found between simulation results and observations in the shape and width of the double layer. This study helps put a constraint on the plasma conditions in which a DL can be expected to form and remain quasistable.

  18. Compressional boundaries in the Earth's foreshock

    SciTech Connect (OSTI)

    Rojas-Castillo, D.; Blanco-Cano, X.; Kajdic, P.; Omidi, N.

    2013-06-13

    The terrestrial foreshock is a highly dynamic region populated by particles, waves and non-linear structures such as shocklets, SLAMS, hot flow anomalies, cavities and cavitons. Recently a new structure named foreshock compressional boundary (FCB) was reported in global hybrid simulations by Omidi et al. (2009). This structure represents a transition region that separates the highly disturbed foreshock plasma from pristine solar wind or from the region of field-aligned ion beams. The FCB is associated with a strong compression of magnetic field and density. Besides the enhancements in the field and density, the FCB also shows a region where these two quantities decrease below the ambient solar wind (SW) values. Here, we study a FCB observed by Cluster-1. This FCB shows that although sometimes FCBs are transition regions between the pristine solar wind plasma and the foreshock plasma, in this case the FCB separates a region with large amplitude waves from regions with high frequency (f{approx}1.7 Hz) small amplitude waves. We analyze the FCB properties, ion distributions inside them, and the waves near the structure.

  19. Doped LZO buffer layers for laminated conductors

    DOE Patents [OSTI]

    Paranthaman, Mariappan Parans [Knoxville, TN; Schoop, Urs [Westborough, MA; Goyal, Amit [Knoxville, TN; Thieme, Cornelis Leo Hans [Westborough, MA; Verebelyi, Darren T [Oxford, MA; Rupich, Martin W [Framingham, MA

    2010-03-23

    A laminated conductor includes a metallic substrate having a surface, a biaxially textured buffer layer supported by the surface of the substrate, the biaxially textured buffer layer comprising LZO and a dopant for mitigating metal diffusion through the LZO, and a biaxially textured conductor layer supported by the biaxially textured buffer layer.

  20. Fast wave evanescence in filamentary boundary plasmas

    SciTech Connect (OSTI)

    Myra, J. R.

    2014-02-15

    Radio frequency waves for heating and current drive of plasmas in tokamaks and other magnetic confinement devices must first traverse the scrape-off-layer (SOL) before they can be put to their intended use. The SOL plasma is strongly turbulent and intermittent in space and time. These turbulent properties of the SOL, which are not routinely taken into account in wave propagation codes, can have an important effect on the coupling of waves through an evanescent SOL or edge plasma region. The effective scale length for fast wave (FW) evanescence in the presence of short-scale field-aligned filamentary plasma turbulence is addressed in this paper. It is shown that although the FW wavelength or evanescent scale length is long compared with the dimensions of the turbulence, the FW does not simply average over the turbulent density; rather, the average is over the exponentiation rate. Implications for practical situations are discussed.

  1. Lubricant-infused nanoparticulate coatings assembled by layer...

    Office of Scientific and Technical Information (OSTI)

    Lubricant-infused nanoparticulate coatings assembled by layer-by-layer deposition Title: Lubricant-infused nanoparticulate coatings assembled by layer-by-layer deposition ...

  2. Weather Research and Forecasting Model with the Immersed Boundary Method

    Energy Science and Technology Software Center (OSTI)

    2012-05-01

    The Weather Research and Forecasting (WRF) Model with the immersed boundary method is an extension of the open-source WRF Model available for wwww.wrf-model.org. The new code modifies the gridding procedure and boundary conditions in the WRF model to improve WRF's ability to simutate the atmosphere in environments with steep terrain and additionally at high-resolutions.

  3. Organic photovoltaic cells utilizing ultrathin sensitizing layer

    DOE Patents [OSTI]

    Rand, Barry P.; Forrest, Stephen R.

    2011-05-24

    A photosensitive device includes a series of organic photoactive layers disposed between two electrodes. Each layer in the series is in direct contact with a next layer in the series. The series is arranged to form at least one donor-acceptor heterojunction, and includes a first organic photoactive layer comprising a first host material serving as a donor, a thin second organic photoactive layer comprising a second host material disposed between the first and a third organic photoactive layer, and the third organic photoactive layer comprising a third host material serving as an acceptor. The first, second, and third host materials are different. The thin second layer serves as an acceptor relative to the first layer or as a donor relative to the third layer.

  4. Buffer layer for thin film structures

    DOE Patents [OSTI]

    Foltyn, Stephen R.; Jia, Quanxi; Arendt, Paul N.; Wang, Haiyan

    2006-10-31

    A composite structure including a base substrate and a layer of a mixture of strontium titanate and strontium ruthenate is provided. A superconducting article can include a composite structure including an outermost layer of magnesium oxide, a buffer layer of strontium titanate or a mixture of strontium titanate and strontium ruthenate and a top-layer of a superconducting material such as YBCO upon the buffer layer.

  5. Buffer layer for thin film structures

    DOE Patents [OSTI]

    Foltyn, Stephen R.; Jia, Quanxi; Arendt, Paul N.; Wang, Haiyan

    2010-06-15

    A composite structure including a base substrate and a layer of a mixture of strontium titanate and strontium ruthenate is provided. A superconducting article can include a composite structure including an outermost layer of magnesium oxide, a buffer layer of strontium titanate or a mixture of strontium titanate and strontium ruthenate and a top-layer of a superconducting material such as YBCO upon the buffer layer.

  6. Chemical solution seed layer for rabits tapes

    DOE Patents [OSTI]

    Goyal, Amit; Paranthaman, Mariappan; Wee, Sung-Hun

    2014-06-10

    A method for making a superconducting article includes the steps of providing a biaxially textured substrate. A seed layer is then deposited. The seed layer includes a double perovskite of the formula A.sub.2B'B''O.sub.6, where A is rare earth or alkaline earth metal and B' and B'' are different rare earth or transition metal cations. A superconductor layer is grown epitaxially such that the superconductor layer is supported by the seed layer.

  7. Experimental study of the influence of collector height on the steady state performance of a passive solar air heater

    SciTech Connect (OSTI)

    Ryan, D.; Burek, S.A.M.

    2010-09-15

    Passive solar air heaters, such as solar chimneys and Trombe Walls, rely on solar-induced buoyancy-driven (natural) convection to produce the flow of air. Although buoyancy-driven convection is well understood for a single vertical plate, buoyancy-driven convection in an asymmetrically-heated channel is more problematic, and in particular, the effects of the channel height on the flow rate and heat transfer. This paper reports on experiments on test rigs resembling lightweight passive solar air-heating collectors. The test rigs were of heights 0.5, 1.0 and 2.0 m, with adjustable channel depths (20-150 mm) and heat inputs (up to 1000 W/m{sup 2}). Measurements were made of the air, plate and cover temperatures, and air velocities. Results are presented as dimensionless correlations of mass flow (as Reynolds number) and efficiency against heat input (as Rayleigh number), channel depth and height. Thermal efficiency is shown to be a function of the heat input and the system height, but not of the channel depth; mass flow is shown to be a dependent on all three parameters. (author)

  8. The commanding heights of oil: Control over the International oil market

    SciTech Connect (OSTI)

    Krapels, E.N.

    1992-01-01

    The Commanding Heights of Oil is an analysis of oil's role in the international environment. It identifies the degree of control over oil in terms of what is asserted as the most important processes and factors that determine the condition of international affairs: (1) The state of oil demand in relation to the capacity to supply, with special emphasis on the amount of spare production capacity; (2) The nature of the business, and how the structure of the industry changes over time as companies cope with the risks peculiar to an extremely capital intensive enterprise; (3) The financial strength of the parties contending for control, including their ability to outlast their opponents in contests for influence over oil affairs; and (4) The nature of the mechanisms whereby the governments and companies strive to create a situation in which they do not have to rely on price to balance supply and demand. Each of the four central factors was prominent at every major turn of the international oil market over the decades. The dissertation argues that the international oil market was controlled in the past by first a group of companies, and, later, a group of countries, for a combination of reasons that is unlikely to be repeated. That does not mean that the 1990s will be spared oil price shocks such as occurred in the 1970s and 1980s. It does suggest that those shocks are unlikely to last long, that OPEC members are unlikely to be able to leverage their position in oil into larger positions in world affairs. It means that oil is unlikely to play as prominent a role in world affairs in the 1990s as it has in the past, even if oil demand, and along with it dependence on OPEC oil, rises.

  9. Oxygen Diffusion Enables Anti-Wear Boundary Film Formation on Titanium Surfaces in Zinc-Dialkyl-Dithiophosphate (ZDDP)-Containing Lubricants

    SciTech Connect (OSTI)

    Qu, Jun; Blau, Peter Julian; Howe, Jane Y; Meyer III, Harry M

    2009-01-01

    This paper reports a wear reduction by up to six orders of magnitude for Ti-6Al-4V alloy when treated by an oxygen diffusion (OD) process and subsequently tested in a zinc-dialkyl-dithiophosphate (ZDDP)-containing lubricant. In addition to case hardening, it is discovered that OD enables the formation of an anti-wear boundary film on the titanium surface. Transmission electron microscopy and surface chemical analyses revealed that this boundary film has a two-layer structure comprising an amorphous oxide interlayer and a ZDDP-based top film with complex compounds.

  10. A boundary-value problem in weighted Hlder spaces for elliptic equations which degenerate at the boundary of the domain

    SciTech Connect (OSTI)

    Bazalii, B V; Degtyarev, S P

    2013-07-31

    An elliptic boundary-value problem for second-order equations with nonnegative characteristic form is investigated in the situation when there is a weak degeneracy on the boundary of the domain. A priori estimates are obtained for solutions and the problem is proved to be solvable in some weighted Hlder spaces. Bibliography: 18 titles.

  11. Layered Atlantic Smoke Interactions with Clouds (LASIC) Science Plan

    SciTech Connect (OSTI)

    Zuidema, P; Chiu, C; Fairall, CW; Ghan, SJ; Kollias, P; McFarguhar, GM; Mechem, DB; Romps, DM; Wong, H; Yuter, SE; Alvarado, MJ; DeSzoeke, SP; Feingold, G; Haywood, JM; Lewis, ER; McComiskey, A; Redemann, J; Turner, DD; Wood, R; Zhu, P

    2015-12-01

    Southern Africa is the world’s largest emitter of biomass-burning (BB) aerosols. Their westward transport over the remote southeast Atlantic Ocean colocates some of the largest atmospheric loadings of absorbing aerosol with the least examined of the Earth’s major subtropical stratocumulus decks. Global aerosol model results highlight that the largest positive top-of-atmosphere forcing in the world occurs in the southeast Atlantic, but this region exhibits large differences in magnitude and sign between reputable models, in part because of high variability in the underlying model cloud distributions. Many uncertainties contribute to the highly variable model radiation fields: the aging of shortwave-absorbing aerosol during transport, how much of the aerosol mixes into the cloudy boundary layer, and how the low clouds adjust to smoke-radiation and smoke-cloud interactions. In addition, the ability of the BB aerosol to absorb shortwave radiation is known to vary seasonally as the fuel type on land changes.

  12. (Environmental and geophysical modeling, fracture mechanics, and boundary element methods)

    SciTech Connect (OSTI)

    Gray, L.J.

    1990-11-09

    Technical discussions at the various sites visited centered on application of boundary integral methods for environmental modeling, seismic analysis, and computational fracture mechanics in composite and smart'' materials. The traveler also attended the International Association for Boundary Element Methods Conference at Rome, Italy. While many aspects of boundary element theory and applications were discussed in the papers, the dominant topic was the analysis and application of hypersingular equations. This has been the focus of recent work by the author, and thus the conference was highly relevant to research at ORNL.

  13. A Cartesian embedded boundary method for hyperbolic conservation laws

    SciTech Connect (OSTI)

    Sjogreen, B; Petersson, N A

    2006-12-04

    The authors develop an embedded boundary finite difference technique for solving the compressible two- or three-dimensional Euler equations in complex geometries on a Cartesian grid. The method is second order accurate with an explicit time step determined by the grid size away from the boundary. Slope limiters are used on the embedded boundary to avoid non-physical oscillations near shock waves. They show computed examples of supersonic flow past a cylinder and compare with results computed on a body fitted grid. Furthermore, they discuss the implementation of the method for thin geometries, and show computed examples of transonic flow past an airfoil.

  14. Study of energy conversion and partitioning in the magnetic reconnection layer of a laboratory plasma

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

    Yamada, Masaaki; Yoo, Jongsoo; Jara-Almonte, Jonathan; Daughton, William; Ji, Hantao; Kulsrud, Russell M.; Myers, Clayton E.

    2015-05-15

    The most important feature of magnetic reconnection is that it energizes plasma particles by converting magnetic energy to particle energy, the exact mechanisms by which this happens are yet to be determined despite a long history of reconnection research. Recently, we have reported our results on the energy conversion and partitioning in a laboratory reconnection layer in a short communication [Yamada et al., Nat. Commun. 5, 4474 (2014)]. The present paper is a detailed elaboration of this report together with an additional dataset with different boundary sizes. Our experimental study of the reconnection layer is carried out in the two-fluidmore » physics regime where ions and electrons move quite differently. We have observed that the conversion of magnetic energy occurs across a region significantly larger than the narrow electron diffusion region. A saddle shaped electrostatic potential profile exists in the reconnection plane, and ions are accelerated by the resulting electric field at the separatrices. These accelerated ions are then thermalized by re-magnetization in the downstream region. A quantitative inventory of the converted energy is presented in a reconnection layer with a well-defined, variable boundary. We also carried out a systematic study of the effects of boundary conditions on the energy inventory. This study concludes that about 50% of the inflowing magnetic energy is converted to particle energy, 2/3 of which is ultimately transferred to ions and 1/3 to electrons. When assisted by another set of magnetic reconnection experiment data and numerical simulations with different sizes of monitoring box, it is also observed that the observed features of energy conversion and partitioning do not depend on the size of monitoring boundary across the range of sizes tested from 1.5 to 4 ion skin depths.« less

  15. Study of energy conversion and partitioning in the magnetic reconnection layer of a laboratory plasma

    SciTech Connect (OSTI)

    Yamada, Masaaki; Yoo, Jongsoo; Jara-Almonte, Jonathan; Daughton, William; Ji, Hantao; Kulsrud, Russell M.; Myers, Clayton E.

    2015-05-15

    The most important feature of magnetic reconnection is that it energizes plasma particles by converting magnetic energy to particle energy, the exact mechanisms by which this happens are yet to be determined despite a long history of reconnection research. Recently, we have reported our results on the energy conversion and partitioning in a laboratory reconnection layer in a short communication [Yamada et al., Nat. Commun. 5, 4474 (2014)]. The present paper is a detailed elaboration of this report together with an additional dataset with different boundary sizes. Our experimental study of the reconnection layer is carried out in the two-fluid physics regime where ions and electrons move quite differently. We have observed that the conversion of magnetic energy occurs across a region significantly larger than the narrow electron diffusion region. A saddle shaped electrostatic potential profile exists in the reconnection plane, and ions are accelerated by the resulting electric field at the separatrices. These accelerated ions are then thermalized by re-magnetization in the downstream region. A quantitative inventory of the converted energy is presented in a reconnection layer with a well-defined, variable boundary. We also carried out a systematic study of the effects of boundary conditions on the energy inventory. This study concludes that about 50% of the inflowing magnetic energy is converted to particle energy, 2/3 of which is ultimately transferred to ions and 1/3 to electrons. When assisted by another set of magnetic reconnection experiment data and numerical simulations with different sizes of monitoring box, it is also observed that the observed features of energy conversion and partitioning do not depend on the size of monitoring boundary across the range of sizes tested from 1.5 to 4 ion skin depths.

  16. Inkjet Deposition of Layer-by-Layer Assembled Films

    SciTech Connect (OSTI)

    Andres, C. M.; Kotov, Nicholas A.

    2010-09-23

    Layer-by-layer assembly (LBL) can create advanced composites with exceptional properties unavailable by other means, but the laborious deposition process and multiple dipping cycles hamper their utilization in microtechnologies and electronics. Multiple rinse steps provide both structural control and thermodynamic stability to LBL multilayers, but they significantly limit their practical applications and contribute significantly to the processing time and waste. Here we demonstrate that by employing inkjet technology one can deliver the necessary quantities of LBL components required for film buildup without excess, eliminating the need for repetitive rinsing steps. This feature differentiates this approach from all other recognized LBL modalities. Using a model system of negatively charged gold nanoparticles and positively charged poly(diallyldimethylammonium) chloride, the material stability, nanoscale control over thickness, and particle coverage offered by the inkjet LBL technique are shown to be equal or better than the case of multilayers made with traditional dipping cycles. The opportunity for fast deposition of complex metallic patterns using a simple inkjet printer is also shown. The additive nature of LBL deposition based on the formation of insoluble nanoparticle-polyelectrolyte complexes of various compositions provides an excellent opportunity for versatile, multicomponent, and noncontact patterning for the simple production of stratified patterns that are much needed in advanced devices.

  17. The Puzzling Boundaries of Topological Quantum Matter | Argonne...

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

    The Puzzling Boundaries of Topological Quantum Matter January 8, 2016 11:00AM to 12:00PM Presenter Michael Levin, University of Chicago Location Building 203 Type Colloquium Series...

  18. Microsoft Word - Gr-hBN boundary state (050214)

    Office of Scientific and Technical Information (OSTI)

    ... B atoms are specified in blue, N atoms are green, carbons are black, and Cu atoms are ... The boundary states are located around 0.1 eV above the Fermi energy. The calculations ...

  19. Mineral Deformation at Earth's Core-Mantle Boundary

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

    (except for its liquid-iron outer core), this convection causes deformation of solid rocks by plastic flow. At the core-mantle boundary (CMB), 2900 km deep, seismologists have...

  20. Science at the interface : grain boundaries in nanocrystalline metals.

    SciTech Connect (OSTI)

    Rodriguez, Mark Andrew; Follstaedt, David Martin; Knapp, James Arthur; Brewer, Luke N.; Holm, Elizabeth Ann; Foiles, Stephen Martin; Hattar, Khalid M.; Clark, Blythe B.; Olmsted, David L.; Medlin, Douglas L.

    2009-09-01

    Interfaces are a critical determinant of the full range of materials properties, especially at the nanoscale. Computational and experimental methods developed a comprehensive understanding of nanograin evolution based on a fundamental understanding of internal interfaces in nanocrystalline nickel. It has recently been shown that nanocrystals with a bi-modal grain-size distribution possess a unique combination of high-strength, ductility and wear-resistance. We performed a combined experimental and theoretical investigation of the structure and motion of internal interfaces in nanograined metal and the resulting grain evolution. The properties of grain boundaries are computed for an unprecedented range of boundaries. The presence of roughening transitions in grain boundaries is explored and related to dramatic changes in boundary mobility. Experimental observations show that abnormal grain growth in nanograined materials is unlike conventional scale material in both the level of defects and the formation of unfavored phases. Molecular dynamics simulations address the origins of some of these phenomena.

  1. Grain boundary and triple junction diffusion in nanocrystalline copper

    SciTech Connect (OSTI)

    Wegner, M. Leuthold, J.; Peterlechner, M.; Divinski, S. V.; Song, X.; Wilde, G.

    2014-09-07

    Grain boundary and triple junction diffusion in nanocrystalline Cu samples with grain sizes, ?d?, of ?35 and ?44?nm produced by spark plasma sintering were investigated by the radiotracer method using the {sup 63}Ni isotope. The measured diffusivities, D{sub eff}, are comparable with those determined previously for Ni grain boundary diffusion in well-annealed, high purity, coarse grained, polycrystalline copper, substantiating the absence of a grain size effect on the kinetic properties of grain boundaries in a nanocrystalline material at grain sizes d???35?nm. Simultaneously, the analysis predicts that if triple junction diffusion of Ni in Cu is enhanced with respect to the corresponding grain boundary diffusion rate, it is still less than 500?D{sub gb} within the temperature interval from 420?K to 470?K.

  2. Schottky barrier height reduction for holes by Fermi level depinning using metal/nickel oxide/silicon contacts

    SciTech Connect (OSTI)

    Islam, Raisul, E-mail: raisul@stanford.edu; Shine, Gautam; Saraswat, Krishna C. [Department of Electrical Engineering, Stanford University, Stanford, California 94305 (United States)

    2014-11-03

    We report the experimental demonstration of Fermi level depinning using nickel oxide (NiO) as the insulator material in metal-insulator-semiconductor (M-I-S) contacts. Using this contact, we show less than 0.1?eV barrier height for holes in platinum/NiO/silicon (Pt/NiO/p-Si) contact. Overall, the pinning factor was improved from 0.08 (metal/Si) to 0.26 (metal/NiO/Si). The experimental results show good agreement with that obtained from theoretical calculation. NiO offers high conduction band offset and low valence band offset with Si. By reducing Schottky barrier height, this contact can be used as a carrier selective contact allowing hole transport but blocking electron transport, which is important for high efficiency in photonic applications such as photovoltaics and optical detectors.

  3. Annealing dependence of diamond-metal Schottky barrier heights probed by hard x-ray photoelectron spectroscopy

    SciTech Connect (OSTI)

    Gaowei, M.; Muller, E. M.; Rumaiz, A. K.; Weiland, C.; Cockayne, E.; Woicik, J. C.; Jordan-Sweet, J.; Smedley, J.

    2012-05-14

    Hard x-ray photoelectron spectroscopy was applied to investigate the diamond-metal Schottky barrier heights for several metals and diamond surface terminations. The position of the diamond valence-band maximum was determined by theoretically calculating the diamond density of states and applying cross section corrections. The diamond-platinum Schottky barrier height was lowered by 0.2 eV after thermal annealing, indicating annealing may increase carrier injection in diamond devices leading to photoconductive gain. The platinum contacts on oxygen-terminated diamond was found to provide a higher Schottky barrier and therefore a better blocking contact than that of the silver contact in diamond-based electronic devices.

  4. Mineral Deformation at Earth's Core-Mantle Boundary

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

    Mineral Deformation at Earth's Core-Mantle Boundary Print Earth is a dynamic planet in which convection takes place on the scale of thousands of kilometers. Because Earth is mostly solid (except for its liquid-iron outer core), this convection causes deformation of solid rocks by plastic flow. At the core-mantle boundary (CMB), 2900 km deep, seismologists have discovered that seismic waves travel faster in certain directions. This seismic anisotropy appears to be related to the deformation of

  5. Mineral Deformation at Earth's Core-Mantle Boundary

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

    Mineral Deformation at Earth's Core-Mantle Boundary Print Earth is a dynamic planet in which convection takes place on the scale of thousands of kilometers. Because Earth is mostly solid (except for its liquid-iron outer core), this convection causes deformation of solid rocks by plastic flow. At the core-mantle boundary (CMB), 2900 km deep, seismologists have discovered that seismic waves travel faster in certain directions. This seismic anisotropy appears to be related to the deformation of

  6. Mineral Deformation at Earth's Core-Mantle Boundary

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

    Mineral Deformation at Earth's Core-Mantle Boundary Print Earth is a dynamic planet in which convection takes place on the scale of thousands of kilometers. Because Earth is mostly solid (except for its liquid-iron outer core), this convection causes deformation of solid rocks by plastic flow. At the core-mantle boundary (CMB), 2900 km deep, seismologists have discovered that seismic waves travel faster in certain directions. This seismic anisotropy appears to be related to the deformation of

  7. Mineral Deformation at Earth's Core-Mantle Boundary

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

    Mineral Deformation at Earth's Core-Mantle Boundary Print Earth is a dynamic planet in which convection takes place on the scale of thousands of kilometers. Because Earth is mostly solid (except for its liquid-iron outer core), this convection causes deformation of solid rocks by plastic flow. At the core-mantle boundary (CMB), 2900 km deep, seismologists have discovered that seismic waves travel faster in certain directions. This seismic anisotropy appears to be related to the deformation of

  8. Mineral Deformation at Earth's Core-Mantle Boundary

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

    Mineral Deformation at Earth's Core-Mantle Boundary Print Earth is a dynamic planet in which convection takes place on the scale of thousands of kilometers. Because Earth is mostly solid (except for its liquid-iron outer core), this convection causes deformation of solid rocks by plastic flow. At the core-mantle boundary (CMB), 2900 km deep, seismologists have discovered that seismic waves travel faster in certain directions. This seismic anisotropy appears to be related to the deformation of

  9. Atom-probe tomography of tribological boundary films resulting from

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

    boron-based oil additives | Argonne National Laboratory Atom-probe tomography of tribological boundary films resulting from boron-based oil additives Title Atom-probe tomography of tribological boundary films resulting from boron-based oil additives Publication Type Journal Article Year of Publication 2016 Authors Kim, Y-J, Baik, S-I, Bertolucci-Coelho, L, Mazzaferro, L, Ramirez, G, Erdemir, A, Seidman, DN Journal Scripta Materialia Volume 111 Start Page 65 Issue 15 Pagination 4 Date

  10. Mineral Deformation at Earth's Core-Mantle Boundary

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

    Mineral Deformation at Earth's Core-Mantle Boundary Print Earth is a dynamic planet in which convection takes place on the scale of thousands of kilometers. Because Earth is mostly solid (except for its liquid-iron outer core), this convection causes deformation of solid rocks by plastic flow. At the core-mantle boundary (CMB), 2900 km deep, seismologists have discovered that seismic waves travel faster in certain directions. This seismic anisotropy appears to be related to the deformation of

  11. Mineral Deformation at Earth's Core-Mantle Boundary

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

    Mineral Deformation at Earth's Core-Mantle Boundary Print Earth is a dynamic planet in which convection takes place on the scale of thousands of kilometers. Because Earth is mostly solid (except for its liquid-iron outer core), this convection causes deformation of solid rocks by plastic flow. At the core-mantle boundary (CMB), 2900 km deep, seismologists have discovered that seismic waves travel faster in certain directions. This seismic anisotropy appears to be related to the deformation of

  12. Mineral Deformation at Earth's Core-Mantle Boundary

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

    Mineral Deformation at Earth's Core-Mantle Boundary Print Earth is a dynamic planet in which convection takes place on the scale of thousands of kilometers. Because Earth is mostly solid (except for its liquid-iron outer core), this convection causes deformation of solid rocks by plastic flow. At the core-mantle boundary (CMB), 2900 km deep, seismologists have discovered that seismic waves travel faster in certain directions. This seismic anisotropy appears to be related to the deformation of

  13. Flavor twisted boundary conditions in the Breit frame

    SciTech Connect (OSTI)

    Jiang, F.-J.; Tiburzi, B. C.

    2008-08-01

    We use a generalization of chiral perturbation theory to account for the effects of flavor twisted boundary conditions in the Breit frame. The relevant framework for two light flavors is an SU(6|4) partially quenched theory, where the extra valence quarks differ only by their boundary conditions. Focusing on the pion electromagnetic form factor, finite volume corrections are calculated at next-to-leading order in the chiral expansion and are estimated to be small on current lattices.

  14. The Puzzling Boundaries of Topological Quantum Matter Michael Levin

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

    Puzzling Boundaries of Topological Quantum Matter Michael Levin University of Chicago October 14, 2015 4:00 p.m. Insulators, by definition, cannot conduct electric current in their interior. However, some insulators - most famously, the recently discovered "topological insulators" - possess the unusual property that they conduct at their surfaces or edges. This conduction occurs through modes that travel along the boundary of the insulator, like waves moving on the surface of the

  15. Twist-averaged boundary conditions for nuclear pasta Hartree-Fock calculations

    SciTech Connect (OSTI)

    Schuetrumpf, B.; Nazarewicz, W.

    2015-10-21

    Nuclear pasta phases, present in the inner crust of neutron stars, are associated with nucleonic matter at subsaturation densities arranged in regular shapes. Those complex phases, residing in a layer which is approximately 100-m thick, impact many features of neutron stars. Theoretical quantum-mechanical simulations of nuclear pasta are usually carried out in finite three-dimensional boxes assuming periodic boundary conditions. The resulting solutions are affected by spurious finite-size effects. To remove spurious finite-size effects, it is convenient to employ twist-averaged boundary conditions (TABC) used in condensed matter, nuclear matter, and lattice quantum chromodynamics applications. In this work, we study the effectiveness of TABC in the context of pasta phase simulations within nuclear density functional theory. We demonstrated that by applying TABC reliable results can be obtained from calculations performed in relatively small volumes. By studying various contributions to the total energy, we gain insights into pasta phases in mid-density range. Future applications will include the TABC extension of the adaptive multiresolution 3D Hartree-Fock solver and Hartree-Fock-Bogoliubov TABC applications to superfluid pasta phases and complex nucleonic topologies as in fission.

  16. Twist-averaged boundary conditions for nuclear pasta Hartree-Fock calculations

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

    Schuetrumpf, B.; Nazarewicz, W.

    2015-10-21

    Nuclear pasta phases, present in the inner crust of neutron stars, are associated with nucleonic matter at subsaturation densities arranged in regular shapes. Those complex phases, residing in a layer which is approximately 100-m thick, impact many features of neutron stars. Theoretical quantum-mechanical simulations of nuclear pasta are usually carried out in finite three-dimensional boxes assuming periodic boundary conditions. The resulting solutions are affected by spurious finite-size effects. To remove spurious finite-size effects, it is convenient to employ twist-averaged boundary conditions (TABC) used in condensed matter, nuclear matter, and lattice quantum chromodynamics applications. In this work, we study the effectivenessmore » of TABC in the context of pasta phase simulations within nuclear density functional theory. We demonstrated that by applying TABC reliable results can be obtained from calculations performed in relatively small volumes. By studying various contributions to the total energy, we gain insights into pasta phases in mid-density range. Future applications will include the TABC extension of the adaptive multiresolution 3D Hartree-Fock solver and Hartree-Fock-Bogoliubov TABC applications to superfluid pasta phases and complex nucleonic topologies as in fission.« less

  17. The Influence of Angiography Table Shields and Height on Patient and Angiographer Irradiation During Interventional Radiology Procedures

    SciTech Connect (OSTI)

    D'Othee, Bertrand Janne Lin, Pei-Jan Paul

    2007-06-15

    Purpose. To quantify the influence of angiography table height on patient and angiographer irradiation, as compared with other routine protective measures such as the use of protective shields hanging at the tableside and from the ceiling of angiography suites. Methods. An experimental study was carried out in which a phantom (substitute for a human body) placed on the angiography table was irradiated by pulsed fluoroscopy. Entrance exposure rates were measured at the phantom surface (surrogate of patient skin exposure by incident X-ray beam) and at 60 cm from the phantom (analog to angiographer skin exposure by scatter). Exposure rates were measured at levels corresponding to the knees, testes, waist, xyphoid appendix, shoulders, and eyes of an angiographer 178 cm tall. Measurements were repeated at angiography table heights of 85, 95, 105, and 110 cm from the floor, with and without protective shields. Results. Moving the table from its highest to lowest position increased by 32% the phantom entrance exposure but decreased scatter to the angiographer. Scatter to the angiographer could be reduced most by using the protective shields (30-105 times less), but low table heights provided relatively more important protection (412-1121 {mu}Sv/hr reduction, or 15-72% scatter reduction) when shields were not used (e.g., for unprotected regions of the angiographer's body such as the hands). Conclusion. Working at lower table heights provides a little additional protection to exposed body parts of angiographers, at the cost of somewhat higher patient exposure. Although small, this incremental protection could be clinically relevant in the long term. The choice of table position should be a compromise based on multiple factors, including at least patient exposure, scatter to angiographers, and angiographer comfort.

  18. Contributions of anharmonic phonon interactions to thermal boundary conductance.

    SciTech Connect (OSTI)

    Hopkins, Patrick E.; Norris, Pamela M.; Duda, John C.

    2010-05-01

    Continued reduction of characteristic dimensions in nanosystems has given rise to increasing importance of material interfaces on the overall system performance. With regard to thermal transport, this increases the need for a better fundamental understanding of the processes affecting interfacial thermal transport, as characterized by the thermal boundary conductance. When thermal boundary conductance is driven by phononic scattering events, accurate predictions of interfacial transport must account for anharmonic phononic coupling as this affects the thermal transmission. In this paper, a new model for phononic thermal boundary conductance is developed that takes into account anharonic coupling, or inelastic scattering events, at the interface between two materials. Previous models for thermal boundary conductance are first reviewed, including the Diffuse Mismatch Model, which only consdiers elastic phonon scattering events, and earlier attempts to account for inelastic phonon scattering, namely, the Maximum Transmission Model and the Higher Harmonic Inelastic model. A new model is derived, the Anharmonic Inelastic Model, which provides a more physical consideration of the effects of inelastic scattering on thermal boundary conductance. This is accomplished by considering specific ranges of phonon frequency interactions and phonon number density conservation. Thus, this model considers the contributions of anharmonic, inelastically scattered phonons to thermal boundary conductance. This new Anharmonic Inelastic Model shows excellent agreement between model predictions and experimental data at the Pb/diamond interface due to its ability to account for the temperature dependent changing phonon population in diamond, which can couple anharmonically with multiple phonons in Pb.

  19. Biaxially textured metal substrate with palladium layer

    DOE Patents [OSTI]

    Robbins, William B.

    2002-12-31

    Described is an article comprising a biaxially textured metal substrate and a layer of palladium deposited on at least one major surface of the metal substrate; wherein the palladium layer has desired in-plane and out-of-plane crystallographic orientations, which allow subsequent layers that are applied on the article to also have the desired orientations.

  20. Enhanced molecular dynamics for simulating porous interphase layers in batteries.

    SciTech Connect (OSTI)

    Zimmerman, Jonathan A.; Wong, Bryan Matthew; Jones, Reese E.; Templeton, Jeremy Alan; Lee, Jonathan

    2009-10-01

    Understanding charge transport processes at a molecular level using computational techniques is currently hindered by a lack of appropriate models for incorporating anistropic electric fields in molecular dynamics (MD) simulations. An important technological example is ion transport through solid-electrolyte interphase (SEI) layers that form in many common types of batteries. These layers regulate the rate at which electro-chemical reactions occur, affecting power, safety, and reliability. In this work, we develop a model for incorporating electric fields in MD using an atomistic-to-continuum framework. This framework provides the mathematical and algorithmic infrastructure to couple finite element (FE) representations of continuous data with atomic data. In this application, the electric potential is represented on a FE mesh and is calculated from a Poisson equation with source terms determined by the distribution of the atomic charges. Boundary conditions can be imposed naturally using the FE description of the potential, which then propagates to each atom through modified forces. The method is verified using simulations where analytical or theoretical solutions are known. Calculations of salt water solutions in complex domains are performed to understand how ions are attracted to charged surfaces in the presence of electric fields and interfering media.

  1. Dense, layered membranes for hydrogen separation

    DOE Patents [OSTI]

    Roark, Shane E.; MacKay, Richard; Mundschau, Michael V.

    2006-02-21

    This invention provides hydrogen-permeable membranes for separation of hydrogen from hydrogen-containing gases. The membranes are multi-layer having a central hydrogen-permeable layer with one or more catalyst layers, barrier layers, and/or protective layers. The invention also relates to membrane reactors employing the hydrogen-permeable membranes of the invention and to methods for separation of hydrogen from a hydrogen-containing gas using the membranes and reactors. The reactors of this invention can be combined with additional reactor systems for direct use of the separated hydrogen.

  2. Solar cell with silicon oxynitride dielectric layer

    SciTech Connect (OSTI)

    Shepherd, Michael; Smith, David D

    2015-04-28

    Solar cells with silicon oxynitride dielectric layers and methods of forming silicon oxynitride dielectric layers for solar cell fabrication are described. For example, an emitter region of a solar cell includes a portion of a substrate having a back surface opposite a light receiving surface. A silicon oxynitride (SiO.sub.xN.sub.y, 0layer is disposed on the back surface of the portion of the substrate. A semiconductor layer is disposed on the silicon oxynitride dielectric layer.

  3. Water Vapor Turbulence Profiles in Stationary Continental Convective Mixed Layers

    SciTech Connect (OSTI)

    Turner, D. D.; Wulfmeyer, Volker; Berg, Larry K.; Schween, Jan

    2014-10-08

    The U.S. Department of Energy Atmospheric Radiation Measurement (ARM) program’s Raman lidar at the ARM Southern Great Plains (SGP) site in north-central Oklahoma has collected water vapor mixing ratio (q) profile data more than 90% of the time since October 2004. Three hundred (300) cases were identified where the convective boundary layer was quasi-stationary and well-mixed for a 2-hour period, and q mean, variance, third order moment, and skewness profiles were derived from the 10-s, 75-m resolution data. These cases span the entire calendar year, and demonstrate that the q variance profiles at the mixed layer (ML) top changes seasonally, but is more related to the gradient of q across the interfacial layer. The q variance at the top of the ML shows only weak correlations (r < 0.3) with sensible heat flux, Deardorff convective velocity scale, and turbulence kinetic energy measured at the surface. The median q skewness profile is most negative at 0.85 zi, zero at approximately zi, and positive above zi, where zi is the depth of the convective ML. The spread in the q skewness profiles is smallest between 0.95 zi and zi. The q skewness at altitudes between 0.6 zi and 1.2 zi is correlated with the magnitude of the q variance at zi, with increasingly negative values of skewness observed lower down in the ML as the variance at zi increases, suggesting that in cases with larger variance at zi there is deeper penetration of the warm, dry free tropospheric air into the ML.

  4. Multi Layer Contaminant Migration Model

    Energy Science and Technology Software Center (OSTI)

    1999-07-28

    This computer software augments and enhances certain calculation included in the previously copyrighted Vadose Zone Contaminant Migration Model. The computational method used in this model recognizes the heterogenous nature of the soils and attempts to account for the variability by using four separate layers to simulate the flow of water through the vadose zone. Therefore, the pore-water velocity calculated by the code will be different than the previous model because it accounts for a widermore » variety of soil properties encountered in the vadose zone. This model also performs an additional screening step than in the previous model. In this model the higher value of two different types of Soil Screening Levels are compared to soil concentrations of contaminants. If the contaminant concentration exceeds the highest of two SSLs, then that contaminant is listed. This is consistent with USEPA's Soil Screening Guidance.« less

  5. Nanomanufacturing : nano-structured materials made layer-by-layer.

    SciTech Connect (OSTI)

    Cox, James V.; Cheng, Shengfeng; Grest, Gary Stephen; Tjiptowidjojo, Kristianto; Reedy, Earl David, Jr.; Fan, Hongyou; Schunk, Peter Randall; Chandross, Michael Evan; Roberts, Scott A.

    2011-10-01

    Large-scale, high-throughput production of nano-structured materials (i.e. nanomanufacturing) is a strategic area in manufacturing, with markets projected to exceed $1T by 2015. Nanomanufacturing is still in its infancy; process/product developments are costly and only touch on potential opportunities enabled by growing nanoscience discoveries. The greatest promise for high-volume manufacturing lies in age-old coating and imprinting operations. For materials with tailored nm-scale structure, imprinting/embossing must be achieved at high speeds (roll-to-roll) and/or over large areas (batch operation) with feature sizes less than 100 nm. Dispersion coatings with nanoparticles can also tailor structure through self- or directed-assembly. Layering films structured with these processes have tremendous potential for efficient manufacturing of microelectronics, photovoltaics and other topical nano-structured devices. This project is designed to perform the requisite R and D to bring Sandia's technology base in computational mechanics to bear on this scale-up problem. Project focus is enforced by addressing a promising imprinting process currently being commercialized.

  6. Fission Product Transport in TRISO Particle Layers under Operating and Off-Normal Conditions

    SciTech Connect (OSTI)

    Van der Ven, Anton; Was, Gary; Wang, Lumin; Taheri, Mitra

    2014-07-07

    The objective of this project is to determine the diffusivity and chemical behavior of key fission products (ag, Cs, I. Te, Eu and Sr) through SiC and PyC both thermally, under irradiation, and under stress using FP introduction techniques that avoid the pitfalls of past experiments. The experimental approach is to create thin PyC-SiC couples containing the fission product to be studied embedded in the PyC layer. These samples will then be subjected to high temperature exposures in a vacuum and also to irradiation at high temperature, and last, to irradiation under stress at high temperature. The PyC serves as a host layer, providing a means of placing the fission product close to the SiC without damaging the SiC layer by its introduction or losing the FP during heating. Experimental measurements of grain boundary structure and distribution (EBSD, HRTEM, APT) will be used in the modeling effort to determine the qualitative dependence of FP diffusion coefficients on grain boundary orientation, temperature and stress.

  7. HC quench layer formation in combustion processes. Technical progress report, September-December 1979

    SciTech Connect (OSTI)

    Lavoie, G A

    1980-02-01

    The project is aimed at understanding wall quenching and other processes responsible for surface generated hydrocarbons in combustion under engine-like conditions. The study concerns the effects of turbulence on the evolution of hydrocarbons. At the conclusion of the program, significant new experimental information will have been generated and an analytical model of the fluid mechanics and some aspects of the chemistry of quenching will be formulated. The work is divided into three tasks: (1) combustion bomb experiments to measure the effect of turbulence on the chemical species near the cold surface; combustion bomb experiments, using a similar turbulence generating device, to fully characterize the flow and turbulence in the vicinity of the quenching surface, and an analytical study to characterize fluid mechanical scales of interest in the boundary layer and to find an analytical solution to describe the evolution of the layer. The major accomplishments to date are (i) demonstration of the feasibility of single shot sampling valve operation and gas analysis in the Ford bomb under laminar combustion conditions, (ii) formulation of design rationale for turbulence generation scheme and bomb geometry, and (iii) formulation of an approach to modeling turbulent boundary layer conditions.

  8. Delineating Bukit Bunuh impact crater boundary by geophysical and geotechnical investigation

    SciTech Connect (OSTI)

    Azwin, I. N. Rosli, S.; Nordiana, M. M.; Ragu, R. R.; Mark, J.; Mokhtar, S.

    2015-03-30

    Evidences of crater morphology and shock metamorphism in Bukit Bunuh, Lenggong, Malaysia were found during the archaeological research conducted by the Centre for Global Archaeological Research Malaysia, Universiti Sains Malaysia. In order to register Bukit Bunuh as one of the world meteorite impact site, detailed studies are needed to verify the boundary of the crater accordingly. Geophysical study was conducted utilising the seismic refraction and 2-D electrical resistivity method. Seismic refraction survey was done using ABEM MK8 24 channel seismograph with 14Hz geophones and 40kg weight drop while 2-D electrical resistivity survey was performed using ABEM SAS4000 Terrameter and ES10-64C electrode selector with pole-dipole array. Bedrock depths were digitized from the sections obtained. The produced bedrock topography map shows that there is low bedrock level circulated by high elevated bedrock and interpreted as crater and rim respectively with diameter approximately 8km. There are also few spots of high elevated bedrock appear at the centre of the crater which interpreted as rebounds zone. Generally, the research area is divided into two layers where the first layer with velocity 400-1100 m/s and resistivity value of 10-800 Om predominantly consists of alluvium mix with gravel and boulders. Second layer represents granitic bedrock with depth of 5-50m having velocity >2100 m/s and resistivity value of >1500 Om. This research is strengthen by good correlation between geophysical data and geotechnical borehole records executed inside and outside of the crater, on the rim, as well as at the rebound area.

  9. DYNA3D Non-reflecting Boundary Conditions - Test Problems

    SciTech Connect (OSTI)

    Zywicz, E

    2006-09-28

    Two verification problems were developed to test non-reflecting boundary segments in DYNA3D (Whirley and Engelmann, 1993). The problems simulate 1-D wave propagation in a semi-infinite rod using a finite length rod and non-reflecting boundary conditions. One problem examines pure pressure wave propagation, and the other problem explores pure shear wave propagation. In both problems the non-reflecting boundary segments yield results that differ only slightly (less than 6%) during a short duration from their corresponding theoretical solutions. The errors appear to be due to the inability to generate a true step-function compressive wave in the pressure wave propagation problem and due to segment integration inaccuracies in the shear wave propagation problem. These problems serve as verification problems and as regression test problems for DYNA3D.

  10. Explicit Expressions for 3D Boundary Integrals in Potential Theory

    SciTech Connect (OSTI)

    Nintcheu Fata, Sylvain

    2009-01-01

    On employing isoparametric, piecewise linear shape functions over a flat triangular domain, exact expressions are derived for all surface potentials involved in the numerical solution of three-dimensional singular and hyper-singular boundary integral equations of potential theory. These formulae, which are valid for an arbitrary source point in space, are represented as analytic expressions over the edges of the integration triangle. They can be used to solve integral equations defined on polygonal boundaries via the collocation method or may be utilized as analytic expressions for the inner integrals in the Galerkin technique. Also, the constant element approximation can be directly obtained with no extra effort. Sample problems solved by the collocation boundary element method for the Laplace equation are included to validate the proposed formulae.

  11. Adequacy of Power-to-Mass Scaling in Simulating PWR Incident Transient for Reduced-Height, Reduced-Pressure and Full-Height, Full-Pressure Integral System Test Facilities

    SciTech Connect (OSTI)

    Liu, T.-J.; Lee, C.-H

    2004-03-15

    A complete scheme of scaling methods to design the reduced-height, reduced-pressure (RHRP) Institute of Nuclear Energy Research Integral System Test (IIST) facility and to specify test conditions for incident simulation was developed. In order to preserve core decay power history and coolant mass inventory during a transient, a unique power-to-mass scaling method is proposed and utilized for RHRP and full-height, full-pressure (FHFP) systems. To validate the current scaling method, three counterpart tests done at the IIST facility are compared with the FHFP tests in small-break loss-of-coolant, station blackout, and loss-of-feedwater accidents performed at the Large-Scale Test Facility (LSTF) and the BETHSY test facility. Although differences appeared in design, scaling, and operation conditions among the IIST, LSTF, and BETHSY test facilities, the important physical phenomena shown in the facilities are almost the same. The physics involved in incident transient phenomena are well measured and modeled by showing the common thermal-hydraulic behavior of key parameters and the general consistency of chronological events. The results also confirm the adequacy of power-to-mass scaling methodology.

  12. Vision for cross-layer optimization to address the dual challenges of energy and reliability

    SciTech Connect (OSTI)

    Quinn, Heather M; Dehon, Andre; Carter, Nicholas P

    2009-01-01

    We are rapidly approaching an inflection point where the conventional target of producing perfect, identical transistors that operate without upset can no longer be maintained while continuing to reduce the energy per operation. With power requirements already limiting chip performance, continuing to demand perfect, upset-free transistors would mean the end of scaling benefits. The big challenges in device variability and reliability are driven by uncommon tails in distributions, infrequent upsets, one-size-fits-all technology requirements, and a lack of information about the context of each operation. Solutions co-designed across traditional layer boundaries in our system stack can change the game, allowing architecture and software (a) to compensate for uncommon variation, environments, and events, (b) to pass down invariants and requirements for the computation, and (c) to monitor the health of collections of deVices. Cross-layer codesign provides a path to continue extracting benefits from further scaled technologies despite the fact that they may be less predictable and more variable. While some limited multi-layer mitigation strategies do exist, to move forward redefining traditional layer abstractions and developing a framework that facilitates cross-layer collaboration is necessary.

  13. Solar collector with blackened layer facing insulation

    SciTech Connect (OSTI)

    Brugger, R.

    1981-05-12

    A solar collector has a surface turned toward the sun and forms a heat exchange cell which has at least one wall composed of sheet aluminum. A tramsmitting layer of such a wall or the absorption layer thereof is a black layer of aluminum oxide containing Ag or Sn and formed unitarily on the aluminum sheet, e.g. By a chemical or electrochemical process.

  14. Superconductive articles including cerium oxide layer

    DOE Patents [OSTI]

    Wu, Xin D.; Muenchausen, Ross E.

    1993-01-01

    A ceramic superconductor comprising a metal oxide substrate, a ceramic high temperature superconductive material, and a intermediate layer of a material having a cubic crystal structure, said layer situated between the substrate and the superconductive material is provided, and a structure for supporting a ceramic superconducting material is provided, said structure comprising a metal oxide substrate, and a layer situated over the surface of the substrate to substantially inhibit interdiffusion between the substrate and a ceramic superconducting material deposited upon said structure.

  15. Manganese containing layer for magnetic recording media

    DOE Patents [OSTI]

    Lambeth, David N.; Lee, Li-Lien; Laughlin, David E.

    1999-01-01

    The present invention provides for a magnetic recording media incorporating Mn-containing layers between a substrate and a magnetic layer to provide media having increased coercivity and lower noise. The Mn-containing layer can be incorporated in a rotating, translating or stationary recording media to operate in conjunction with magnetic transducing heads for recording and reading of magnetic data, as well as other applications. The magnetic recording medium of the invention preferably includes a Co or Co alloy film magnetic layer, and Mn-containing layer, preferably comprised of VMn, TiMn, MnZn, CrMnMo, CrMnW, CrMnV, and CrMnTi, and most preferably a CrMn alloy, disposed between the substrate and the magnetic layer to promote an epitaxial crystalline structure in the magnetic layer. The medium can further include seed layers, preferably polycrystalline MgO for longitudinal media, underlayers, and intermediate layers. Underlayers and intermediate layers are comprised of materials having either an A2 structure or a B2-ordered crystalline structure disposed between the seed layer and the magnetic layer. Materials having an A2 structure are preferably Cr or Cr alloys, such as CrV, CrMo, CrW and CrTi. Materials having a B2-ordered structure having a lattice constant that is substantially comparable to that of Cr, such as those preferably selected from the group consisting of NiAl, AILCo, FeAl, FeTi, CoFe, CoTi, CoHf, CoZr, NiTi, CuBe, CuZn, A-LMn, AlRe, AgMg, and Al.sub.2 FeMn.sub.2, and is most preferably FeAl or NiAl.

  16. Multi-layer seal for electrochemical devices

    DOE Patents [OSTI]

    Chou, Yeong-Shyung [Richland, WA; Meinhardt, Kerry D [Kennewick, WA; Stevenson, Jeffry W [Richland, WA

    2010-09-14

    Multi-layer seals are provided that find advantageous use for reducing leakage of gases between adjacent components of electrochemical devices. Multi-layer seals of the invention include a gasket body defining first and second opposing surfaces and a compliant interlayer positioned adjacent each of the first and second surfaces. Also provided are methods for making and using the multi-layer seals, and electrochemical devices including said seals.

  17. Multi-layer seal for electrochemical devices

    DOE Patents [OSTI]

    Chou, Yeong-Shyung [Richland, WA; Meinhardt, Kerry D [Kennewick, WA; Stevenson, Jeffry W [Richland, WA

    2010-11-16

    Multi-layer seals are provided that find advantageous use for reducing leakage of gases between adjacent components of electrochemical devices. Multi-layer seals of the invention include a gasket body defining first and second opposing surfaces and a compliant interlayer positioned adjacent each of the first and second surfaces. Also provided are methods for making and using the multi-layer seals, and electrochemical devices including said seals.

  18. Method to fabricate layered material compositions

    DOE Patents [OSTI]

    Fleming, James G.; Lin, Shawn-Yu

    2002-01-01

    A new class of processes suited to the fabrication of layered material compositions is disclosed. Layered material compositions are typically three-dimensional structures which can be decomposed into a stack of structured layers. The best known examples are the photonic lattices. The present invention combines the characteristic features of photolithography and chemical-mechanical polishing to permit the direct and facile fabrication of, e.g., photonic lattices having photonic bandgaps in the 0.1-20.mu. spectral range.

  19. Method to fabricate layered material compositions

    DOE Patents [OSTI]

    Fleming, James G.; Lin, Shawn-Yu

    2004-11-02

    A new class of processes suited to the fabrication of layered material compositions is disclosed. Layered material compositions are typically three-dimensional structures which can be decomposed into a stack of structured layers. The best known examples are the photonic lattices. The present invention combines the characteristic features of photolithography and chemical-mechanical polishing to permit the direct and facile fabrication of, e.g., photonic lattices having photonic bandgaps in the 0.1-20.mu. spectral range.

  20. Associations of Pd, U and Ag in the SiC layer of neutron-irradiated TRISO fuel

    SciTech Connect (OSTI)

    Lillo, Thomas; Rooyen, Isabella Van

    2015-05-01

    Knowledge of the associations and composition of fission products in the neutron irradiated SiC layer of high-temperature gas reactor TRISO fuel is important to the understanding of various aspects of fuel performance that presently are not well understood. Recently, advanced characterization techniques have been used to examine fuel particles from the Idaho National Laboratorys AGR-1 experiment. Nano-sized Ag and Pd precipitates were previously identified in grain boundaries and triple points in the SiC layer of irradiated TRISO nuclear fuel. Continuation of this initial research is reported in this paper and consists of the characterization of a relatively large number of nano-sized precipitates in three areas of the SiC layer of a single irradiated TRISO nuclear fuel particle using standardless EDS analysis on focused ion beam-prepared transmission electron microscopy samples. Composition and distribution analyses of these precipitates, which were located on grain boundaries, triple junctions and intragranular precipitates, revealed low levels, generally <10 atomic %, of palladium, silver and/or uranium with palladium being the most common element found. Palladium by itself, or associated with either silver or uranium, was found throughout the SiC layer. A small number of precipitates on grain boundaries and triple junctions were found to contain only silver or silver in association with palladium while uranium was always associated with palladium but never found by itself or in association with silver. Intergranular precipitates containing uranium were found to have migrated ~23 ?m along a radial direction through the 35 ?m thick SiC coating during the AGR-1 experiment while silver-containing intergranular precipitates were found at depths up to ~24 ?m in the SiC layer. Also, Pd-rich, nano-precipitates (~10 nm in diameter), without evidence for the presence of either Ag or U, were revealed in intragranular regions throughout the SiC layer. Because not all

  1. Sodium-layer laser guide stars

    SciTech Connect (OSTI)

    Friedman, H.W.

    1993-08-03

    The requirements and design of a laser system to generate a sodium- layer beacon is presented. Early results of photometry and wavefront sensing are given.

  2. Enhanced Densification of SDC Barrier Layers

    SciTech Connect (OSTI)

    Hardy, John S.; Templeton, Jared W.; Lu, Zigui; Stevenson, Jeffry W.

    2011-09-12

    This technical report explores the Enhanced Densification of SCD Barrier Layers A samaria-doped ceria (SDC) barrier layer separates the lanthanum strontium cobalt ferrite (LSCF) cathode from the yttria-stabilized zirconia (YSZ) electrolyte in a solid oxide fuel cell (SOFC) to prevent the formation of electrically resistive interfacial SrZrO{sub 3} layers that arise from the reaction of Sr from the LSCF with Zr from the YSZ. However, the sintering temperature of this SDC layer must be limited to {approx}1200 C to avoid extensive interdiffusion between SDC and YSZ to form a resistive CeO{sub 2}-ZrO{sub 2} solid solution. Therefore, the conventional SDC layer is often porous and therefore not as impervious to Sr-diffusion as would be desired. In the pursuit of improved SOFC performance, efforts have been directed toward increasing the density of the SDC barrier layer without increasing the sintering temperature. The density of the SDC barrier layer can be greatly increased through small amounts of Cu-doping of the SDC powder together with increased solids loading and use of an appropriate binder system in the screen print ink. However, the resulting performance of cells with these barrier layers did not exhibit the expected increase in accordance with that achieved with the prototypical PLD SDC layer. It was determined by XRD that increased sinterability of the SDC also results in increased interdiffusivity between the SDC and YSZ, resulting in formation of a highly resistive solid solution.

  3. Organic photovoltaic cells utilizing ultrathin sensitizing layer

    DOE Patents [OSTI]

    Forrest, Stephen R.; Yang, Fan; Rand, Barry P.

    2011-09-06

    A photosensitive device includes a plurality of organic photoconductive materials disposed in a stack between a first electrode and a second electrode, including a first continuous layer of donor host material, a second continuous layer of acceptor host material, and at least one other organic photoconductive material disposed as a plurality of discontinuous islands between the first continuous layer and the second continuous layer. Each of these other photoconductive materials has an absorption spectra different from the donor host material and the acceptor host material. Preferably, each of the discontinuous islands consists essentially of a crystallite of the respective organic photoconductive material, and more preferably, the crystallites are nanocrystals.

  4. Development of an Immersed Boundary Method to Resolve Complex Terrain in the Weather Research and Forecasting Model

    SciTech Connect (OSTI)

    Lunquist, K A; Chow, F K; Lundquist, J K; Mirocha, J D

    2007-09-04

    Flow and dispersion processes in urban areas are profoundly influenced by the presence of buildings which divert mean flow, affect surface heating and cooling, and alter the structure of turbulence in the lower atmosphere. Accurate prediction of velocity, temperature, and turbulent kinetic energy fields are necessary for determining the transport and dispersion of scalars. Correct predictions of scalar concentrations are vital in densely populated urban areas where they are used to aid in emergency response planning for accidental or intentional releases of hazardous substances. Traditionally, urban flow simulations have been performed by computational fluid dynamics (CFD) codes which can accommodate the geometric complexity inherent to urban landscapes. In these types of models the grid is aligned with the solid boundaries, and the boundary conditions are applied to the computational nodes coincident with the surface. If the CFD code uses a structured curvilinear mesh, then time-consuming manual manipulation is needed to ensure that the mesh conforms to the solid boundaries while minimizing skewness. If the CFD code uses an unstructured grid, then the solver cannot be optimized for the underlying data structure which takes an irregular form. Unstructured solvers are therefore often slower and more memory intensive than their structured counterparts. Additionally, urban-scale CFD models are often forced at lateral boundaries with idealized flow, neglecting dynamic forcing due to synoptic scale weather patterns. These CFD codes solve the incompressible Navier-Stokes equations and include limited options for representing atmospheric processes such as surface fluxes and moisture. Traditional CFD codes therefore posses several drawbacks, due to the expense of either creating the grid or solving the resulting algebraic system of equations, and due to the idealized boundary conditions and the lack of full atmospheric physics. Meso-scale atmospheric boundary layer

  5. Subjective surfaces: a geometric model for boundary completion

    SciTech Connect (OSTI)

    Sarti, Alessandro; Malladi, Ravi; Sethian, J.A.

    2000-06-01

    We present a geometric model and a computational method for segmentation of images with missing boundaries. In many situations, the human visual system fills in missing gaps in edges and boundaries, building and completing information that is not present. Boundary completion presents a considerable challenge in computer vision, since most algorithms attempt to exploit existing data. A large body of work concerns completion models, which postulate how to construct missing data; these models are often trained and specific to particular images. In this paper, we take the following, alternative perspective: we consider a reference point within an image as given, and then develop an algorithm which tries to build missing information on the basis of the given point of view and the available information as boundary data to the algorithm. Starting from this point of view, a surface is constructed. It is then evolved with the mean curvature flow in the metric induced by the image until a piecewise constant solution is reached. We test the computational model on modal completion, amodal completion, texture, photo and medical images. We extend the geometric model and the algorithm to 3D in order to extract shapes from low signal/noise ratio medical volumes. Results in 3D echocardiography and 3D fetal echography are presented.

  6. Atomic Layer Deposition | Argonne National Laboratory

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

    Atomic Layer Deposition New nanophase thin film materials with properties tailored to specifically meet the needs of industry New software simulates ALD over multiple length scale, saving industry time and money on developing specialized tools PDF icon Atomic_Layer_Deposition

  7. Epitaxial growth of silicon for layer transfer

    DOE Patents [OSTI]

    Teplin, Charles; Branz, Howard M

    2015-03-24

    Methods of preparing a thin crystalline silicon film for transfer and devices utilizing a transferred crystalline silicon film are disclosed. The methods include preparing a silicon growth substrate which has an interface defining substance associated with an exterior surface. The methods further include depositing an epitaxial layer of silicon on the silicon growth substrate at the surface and separating the epitaxial layer from the substrate substantially along the plane or other surface defined by the interface defining substance. The epitaxial layer may be utilized as a thin film of crystalline silicon in any type of semiconductor device which requires a crystalline silicon layer. In use, the epitaxial transfer layer may be associated with a secondary substrate.

  8. Instability limits for spontaneous double layer formation

    SciTech Connect (OSTI)

    Carr, J. Jr.; Department of Physics, Texas Lutheran University, Seguin, Texas 78155 ; Galante, M. E.; McCarren, D.; Scime, E. E.; Sears, S.; VanDervort, R. W.; Magee, R. M.; TriAlpha Energy, Inc., Foothill Ranch, California 92610 ; Reynolds, E.

    2013-11-15

    We present time-resolved measurements that demonstrate that large amplitude electrostatic instabilities appear in pulsed, expanding helicon plasmas at the same time as particularly strong double layers appear in the expansion region. A significant cross-correlation between the electrostatic fluctuations and fluctuations in the number of ions accelerated by the double layer electric field is observed. No correlation is observed between the electrostatic fluctuations and ions that have not passed through the double layer. These measurements confirm that the simultaneous appearance of the electrostatic fluctuations and the double layer is not simple coincidence. In fact, the accelerated ion population is responsible for the growth of the instability. The double layer strength, and therefore, the velocity of the accelerated ions, is limited by the appearance of the electrostatic instability.

  9. Microstructures and microhardness at fusion boundary of 316 stainless steel/Inconel 182 dissimilar welding

    SciTech Connect (OSTI)

    Wang, Wei; Lu, Yonghao; Ding, Xianfei; Shoji, Tetsuo

    2015-09-15

    Microstructures and microhardness at fusion boundary of a weld joint were investigated in a 316 stainless steel/Inconel 182 dissimilar weldment. The results showed that there were two alternately distributed typical fusion boundaries, a narrow random boundary (possessed 15% in length) with a clear sharp interface and an epitaxial fusion one with (100){sub BM}//(100){sub WM} at the joint interface. The composition transition, microstructure and hardness across the fusion boundary strongly depended on the type of the fusion boundary. For the random boundary, there was a clear sharp interface and the composition transition with a width of 100 μm took place symmetrically across the grain boundary. For the epitaxial fusion one, however, there were Type-I and Type-II grain boundaries perpendicular and parallel to the epitaxial fusion boundary, respectively. The composition transition took place in the Inconel 182 weld side. Σ3 boundaries in the HAZ of 316SS side and Σ5 grain boundaries in weld metal were usually observed, despite the type of fusion boundary, however the former was much more in epitaxial fusion boundary. Microhardness was continuously decreased across the random fusion boundary from the side of Inconel 182 to 316SS, but a hardening phenomenon appeared in the epitaxial fusion boundary zone because of its fine cellular microstructure. - Highlights: • Two typical fusion boundaries alternately distributed in the fusion interface • The microstructure, composition and hardness across fusion boundary depended on its type. • Different regions in welded joint have different special CSL value boundaries. • Hardening phenomenon only appeared in the epitaxial fusion boundary.

  10. Amorphous silicon Schottky barrier solar cells incorporating a thin insulating layer and a thin doped layer

    DOE Patents [OSTI]

    Carlson, David E.

    1980-01-01

    Amorphous silicon Schottky barrier solar cells which incorporate a thin insulating layer and a thin doped layer adjacent to the junction forming metal layer exhibit increased open circuit voltages compared to standard rectifying junction metal devices, i.e., Schottky barrier devices, and rectifying junction metal insulating silicon devices, i.e., MIS devices.

  11. Thermoelectric material including conformal oxide layers and method of making the same using atomic layer deposition

    DOE Patents [OSTI]

    Cho, Jung Young; Ahn, Dongjoon; Salvador, James R.; Meisner, Gregory P.

    2016-06-07

    A thermoelectric material includes a substrate particle and a plurality of conformal oxide layers formed on the substrate particle. The plurality of conformal oxide layers has a total oxide layer thickness ranging from about 2 nm to about 20 nm. The thermoelectric material excludes oxide nanoparticles. A method of making the thermoelectric material is also disclosed herein.

  12. Using Mesoscale Weather Model Output as Boundary Conditions for Atmospheric Large-Eddy Simulations and Wind-Plant Aerodynamic Simulations (Presentation)

    SciTech Connect (OSTI)

    Churchfield, M. J.; Michalakes, J.; Vanderwende, B.; Lee, S.; Sprague, M. A.; Lundquist, J. K.; Moriarty, P. J.

    2013-10-01

    Wind plant aerodynamics are directly affected by the microscale weather, which is directly influenced by the mesoscale weather. Microscale weather refers to processes that occur within the atmospheric boundary layer with the largest scales being a few hundred meters to a few kilometers depending on the atmospheric stability of the boundary layer. Mesoscale weather refers to large weather patterns, such as weather fronts, with the largest scales being hundreds of kilometers wide. Sometimes microscale simulations that capture mesoscale-driven variations (changes in wind speed and direction over time or across the spatial extent of a wind plant) are important in wind plant analysis. In this paper, we present our preliminary work in coupling a mesoscale weather model with a microscale atmospheric large-eddy simulation model. The coupling is one-way beginning with the weather model and ending with a computational fluid dynamics solver using the weather model in coarse large-eddy simulation mode as an intermediary. We simulate one hour of daytime moderately convective microscale development driven by the mesoscale data, which are applied as initial and boundary conditions to the microscale domain, at a site in Iowa. We analyze the time and distance necessary for the smallest resolvable microscales to develop.

  13. A Bayesian inversion framework for yield and height-of-burst/depth-of-burial for near-surface explosions

    SciTech Connect (OSTI)

    Johannesson, Gardar; Bulaevskaya, Vera; Ramirez, Abe; Ford, Sean; Rodgers, Artie

    2015-09-07

    A Bayesian inversion framework is presented to estimate the yield of an explosion and height-of-burst/depth-of-burial (HOB/DOB) using seismic and air pressure data. This is accomplished by first calibrating the parameters in the forward models that relate the observations to the yield and HOB/DOB and then using the calibrated model to estimate yield and HOB/DOB associated with a new set of seismic and air pressure observations. The MCMC algorithms required to perform these steps are outlined, and the results with real data are shown. Finally, an extension is proposed for a case when clustering in the seismic displacement occurs as a function of different types of rock and other factors.

  14. Low resistance Ti Ohmic contacts to 4H-SiC by reducing barrier heights without high temperature annealing

    SciTech Connect (OSTI)

    Huang Lingqin; Liu Bingbing; Zhu Qiaozhi; Chen Suhua; Gao Mingchao; Wang Dejun; Qin Fuwen

    2012-06-25

    Ti Ohmic contacts to relatively highly doped (1 Multiplication-Sign 10{sup 18} cm{sup -3}) n-type 4H-SiC have been produced, without high temperature annealing, by means of low temperature electronic cyclotron resonance microwave hydrogen plasma pre-treatment (HPT) of the SiC surface. The as-deposited Ti/4H-SiC contacts show Ohmic properties, and the specific contact resistance obtained is as low as 2.07 Multiplication-Sign 10{sup -4}{Omega}{center_dot}cm{sup 2} after annealing at low temperatures (400 Degree-Sign C). This is achieved by low barrier height at Ti/SiC interface, which could be attributed to decrease of surface states density by the HPT releasing Fermi level pinning, and to band-gap narrowing, image-force, and thermionic-field emission at high doping.

  15. Improved Power Conversion Efficiency of InP Solar Cells Using Organic Window Layers

    SciTech Connect (OSTI)

    Li, N; Lee, K.; Renshaw, C. K.; Xiao, X.; Forrest, Stephen R.

    2011-01-01

    We employ the organic semiconductor 3,4,9,10-perylene-tetracarboxylic-dianhydride (PTCDA) as a nanometer thick window layer for p-InP/indium tin oxide (ITO) Schottky barrierdiodesolar cells. The power conversion efficiency is enhanced compared to ITO/InP cells lacking the PTCDA window layer, primarily due to neutralizing InP surface state charges via hole injection from the PTCDA. This leads to an increased ITO/p-InP Schottky barrier height, and hence to an increased open circuit voltage. The power conversion efficiency of the cells increases from 13.2±0.5% for the ITO/InP cell to 15.4±0.4% for the ITO/4 nm PTCDA/p-InP cell under 1 sun, AM1.5G simulated solar illumination. The PTCDA window layer is also shown to contribute to the photocurrent by light absorption followed by exciton dissociation at the organic/inorganic semiconductor interface.

  16. The Effect of High Temperature Annealing on the Grain Characteristics of a Thin Chemical Vapor Deposition Silicon Carbide Layer.

    SciTech Connect (OSTI)

    Isabella J van Rooyen; Philippus M van Rooyen; Mary Lou Dunzik-Gougar

    2013-08-01

    The unique combination of thermo-mechanical and physiochemical properties of silicon carbide (SiC) provides interest and opportunity for its use in nuclear applications. One of the applications of SiC is as a very thin layer in the TRi-ISOtropic (TRISO) coated fuel particles for high temperature gas reactors (HTGRs). This SiC layer, produced by chemical vapor deposition (CVD), is designed to withstand the pressures of fission and transmutation product gases in a high temperature, radiation environment. Various researchers have demonstrated that macroscopic properties can be affected by changes in the distribution of grain boundary plane orientations and misorientations [1 - 3]. Additionally, various researchers have attributed the release behavior of Ag through the SiC layer as a grain boundary diffusion phenomenon [4 - 6]; further highlighting the importance of understanding the actual grain characteristics of the SiC layer. Both historic HTGR fission product release studies and recent experiments at Idaho National Laboratory (INL) [7] have shown that the release of Ag-110m is strongly temperature dependent. Although the maximum normal operating fuel temperature of a HTGR design is in the range of 1000-1250C, the temperature may reach 1600C under postulated accident conditions. The aim of this specific study is therefore to determine the magnitude of temperature dependence on SiC grain characteristics, expanding upon initial studies by Van Rooyen et al, [8; 9].

  17. ARM - Presentations, Reports, and Lectures

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

    ApplicationsPresentations, Reports, and Lectures Summer Training Information Training Home Agenda Instructor Bios Project Reports, Presentations, and Lectures Images Presentations, Reports, and Lectures Boundary Layer Structure Instructors: Ewan O'Connor, Virendra Ghate team_1_edits Students: Jae-In Song, Suzane de Sá, Shaoyue Qiu, Thiago Biscaro Project Presentation: Boundary Layer Structure: A Comparison Between Methods and Sites Report: Planetary Boundary Layer Height: A Comparison of

  18. Molecular dynamics simulations of grain boundaries in thin nanocrystalline silicon films

    SciTech Connect (OSTI)

    Berman, G.P.; Doolen, G.D.; Mainieri, R.; Campbell, D.K.; Luchnikov, V.A. |

    1997-10-01

    Using molecular dynamics simulations, the grain boundaries in thin polycrystalline silicon films (considered as promising material for future nanoelectronic devices) are investigated. It is shown that in polysilicon film with randomly oriented grains the majority of grain boundaries are disordered. However, some grains with small mutual orientation differences can form extended crystalline patterns. The structure of the grain boundaries satisfies the thermodynamical criterion. The majority of atoms in the grain boundaries are tetrahedrally coordinated with the nearest neighbors, even though the grain boundaries are disordered. The grain boundary matter is characterized as an amorphous phase with a characteristic tetragonality value.

  19. Superconducting composite with multilayer patterns and multiple buffer layers

    DOE Patents [OSTI]

    Wu, Xin D.; Muenchausen, Ross E.

    1993-01-01

    An article of manufacture including a substrate, a patterned interlayer of a material selected from the group consisting of magnesium oxide, barium-titanium oxide or barium-zirconium oxide, the patterned interlayer material overcoated with a secondary interlayer material of yttria-stabilized zirconia or magnesium-aluminum oxide, upon the surface of the substrate whereby an intermediate article with an exposed surface of both the overcoated patterned interlayer and the substrate is formed, a coating of a buffer layer selected from the group consisting of cerium oxide, yttrium oxide, curium oxide, dysprosium oxide, erbium oxide, europium oxide, iron oxide, gadolinium oxide, holmium oxide, indium oxide, lanthanum oxide, manganese oxide, lutetium oxide, neodymium oxide, praseodymium oxide, plutonium oxide, samarium oxide, terbium oxide, thallium oxide, thulium oxide, yttrium oxide and ytterbium oxide over the entire exposed surface of the intermediate article, and, a ceramic superco n FIELD OF THE INVENTION The present invention relates to the field of superconducting articles having two distinct regions of superconductive material with differing in-plane orientations whereby the conductivity across the boundary between the two regions can be tailored. This invention is the result of a contract with the Department of Energy (Contract No. W-7405-ENG-36).

  20. Method for forming a barrier layer

    DOE Patents [OSTI]

    Weihs, Timothy P. (Baltimore, MD); Barbee, Jr., Troy W. (Palo Alto, CA)

    2002-01-01

    Cubic or metastable cubic refractory metal carbides act as barrier layers to isolate, adhere, and passivate copper in semiconductor fabrication. One or more barrier layers of the metal carbide are deposited in conjunction with copper metallizations to form a multilayer characterized by a cubic crystal structure with a strong (100) texture. Suitable barrier layer materials include refractory transition metal carbides such as vanadium carbide (VC), niobium carbide (NbC), tantalum carbide (TaC), chromium carbide (Cr.sub.3 C.sub.2), tungsten carbide (WC), and molybdenum carbide (MoC).

  1. Superconductive articles including cerium oxide layer

    DOE Patents [OSTI]

    Wu, X.D.; Muenchausen, R.E.

    1993-11-16

    A ceramic superconductor comprising a metal oxide substrate, a ceramic high temperature superconductive material, and a intermediate layer of a material having a cubic crystal structure, said layer situated between the substrate and the superconductive material is provided, and a structure for supporting a ceramic superconducting material is provided, said structure comprising a metal oxide substrate, and a layer situated over the surface of the substrate to substantially inhibit interdiffusion between the substrate and a ceramic superconducting material deposited upon said structure. 7 figures.

  2. Strained layer Fabry-Perot device

    DOE Patents [OSTI]

    Brennan, Thomas M.; Fritz, Ian J.; Hammons, Burrell E.

    1994-01-01

    An asymmetric Fabry-Perot reflectance modulator (AFPM) consists of an active region between top and bottom mirrors, the bottom mirror being affixed to a substrate by a buffer layer. The active region comprises a strained-layer region having a bandgap and thickness chosen for resonance at the Fabry-Perot frequency. The mirrors are lattice matched to the active region, and the buffer layer is lattice matched to the mirror at the interface. The device operates at wavelengths of commercially available semiconductor lasers.

  3. Warm Bias and Parameterization of Boundary Upwelling in Ocean Models

    SciTech Connect (OSTI)

    Cessi, Paola; Wolfe, Christopher

    2012-11-06

    It has been demonstrated that Eastern Boundary Currents (EBC) are a baroclinic intensification of the interior circulation of the ocean due to the emergence of mesoscale eddies in response to the sharp buoyancy gradients driven by the wind-stress and the thermal surface forcing. The eddies accomplish the heat and salt transport necessary to insure that the subsurface flow is adiabatic, compensating for the heat and salt transport effected by the mean currents. The EBC thus generated occurs on a cross-shore scale of order 20-100 km, and thus this scale needs to be resolved in climate models in order to capture the meridional transport by the EBC. Our result indicate that changes in the near shore currents on the oceanic eastern boundaries are linked not just to local forcing, such as coastal changes in the winds, but depend on the basin-wide circulation as well.

  4. Shock wave convergence in water with parabolic wall boundaries

    SciTech Connect (OSTI)

    Yanuka, D.; Shafer, D.; Krasik, Ya.

    2015-04-28

    The convergence of shock waves in water, where the cross section of the boundaries between which the shock wave propagates is either straight or parabolic, was studied. The shock wave was generated by underwater electrical explosions of planar Cu wire arrays using a high-current generator with a peak output current of ?45?kA and rise time of ?80?ns. The boundaries of the walls between which the shock wave propagates were symmetric along the z axis, which is defined by the direction of the exploding wires. It was shown that with walls having a parabolic cross section, the shock waves converge faster and the pressure in the vicinity of the line of convergence, calculated by two-dimensional hydrodynamic simulations coupled with the equations of state of water and copper, is also larger.

  5. Flavor twisted boundary conditions and the nucleon vector current

    SciTech Connect (OSTI)

    Jiang, F.-J.; Tiburzi, B. C.

    2008-12-01

    Using flavor twisted boundary conditions, we study nucleon matrix elements of the vector current. We twist only the active quarks that couple to the current. Finite volume corrections due to twisted boundary conditions are determined using partially twisted, partially quenched, heavy baryon chiral perturbation theory, which we develop for the graded group SU(7|5). Asymptotically these corrections are exponentially small in the volume, but can become pronounced for small twist angles. Utilizing the Breit frame does not mitigate volume corrections to nucleon vector current matrix elements. The derived expressions will allow for better controlled extractions of the isovector magnetic moment and the electromagnetic radii from simulations at zero lattice momentum. Our formalism, moreover, can be applied to any nucleon matrix elements.

  6. Vegetation Loblolly Pine N Site Boundary N Streams Roads

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

    Loblolly Pine N Site Boundary N Streams Roads [2J Other Set-Asides 6£] Hy~ric Soils < ____ n ____ ** __ ._ ** _______ 300 0 - L " " " " , 300 781 .3a 600 Meters Soils Soil Series and Phase _TrB Figure 4-1. Plant CO/lllllllllties and soils associated with the Loblolly Pine Stand Set-Aside Area. sc 4-5 Set-Aside 4: Loblolly Pine Stand

  7. On the Boundary Condition Between Two Multiplying Media

    DOE R&D Accomplishments [OSTI]

    Friedman, F. L.; Wigner, E. P.

    1944-04-19

    The transition region between two parts of a pile which have different compositions is investigated. In the case where the moderator is the same in both parts of the pile, it is found that the diffusion constant times thermal neutron density plus diffusion constant times fast neutron density satisfies the usual pile equations everywhere, right to the boundary. More complicated formulae apply in a more general case.

  8. Intergranular degradation assessment via random grain boundary network analysis

    DOE Patents [OSTI]

    Kumar, Mukul; Schwartz, Adam J.; King, Wayne E.

    2002-01-01

    A method is disclosed for determining the resistance of polycrystalline materials to intergranular degradation or failure (IGDF), by analyzing the random grain boundary network connectivity (RGBNC) microstructure. Analysis of the disruption of the RGBNC microstructure may be assess the effectiveness of materials processing in increasing IGDF resistance. Comparison of the RGBNC microstructures of materials exposed to extreme operating conditions to unexposed materials may be used to diagnose and predict possible onset of material failure due to

  9. Distribution of Pd, Ag & U in the SiC Layer of an Irradiated TRISO Fuel Particle

    SciTech Connect (OSTI)

    Thomas M. Lillo; Isabella J. van Rooyen

    2014-08-01

    The distribution of silver, uranium and palladium in the silicon carbide (SiC) layer of an irradiated TRISO fuel particle was studied using samples extracted from the SiC layer using focused ion beam (FIB) techniques. Transmission electron microscopy in conjunction with energy dispersive x-ray spectroscopy was used to identify the presence of the specific elements of interest at grain boundaries, triple junctions and precipitates in the interior of SiC grains. Details on sample fabrication, errors associated with measurements of elemental migration distances and the distances migrated by silver, palladium and uranium in the SiC layer of an irradiated TRISO particle from the AGR-1 program are reported.

  10. Determination of Grain Boundary Charging in Cu(In,Ga)Se2 Thin Films: Preprint

    SciTech Connect (OSTI)

    Jiang, C. S.; Contreras, M. A.; Repins, I.; Moutinho, H. R.; Noufi, R.; Al-Jassim, M. M.

    2012-06-01

    Surface potential mapping of Cu(In,Ga)Se2 (CIGS) thin films using scanning Kelvin probe force microscopy (SKPFM) aims to understand the minority-carrier recombination at the grain boundaries (GBs) of this polycrystalline material by examining GB charging, which has resulted in a number of publications. However, the reported results are highly inconsistent. In this paper, we report on the potential mapping by measuring wide-bandgap or high-Ga-content films and by using a complementary atomic force microscopy-based electrical technique of scanning capacitance microscopy (SCM). The results demonstrate consistent, positively charged GBs on our high-quality films with minimal surface defects/charges. The potential image taken on a low-quality film with a 1.2-eV bandgap shows significantly degraded potential contrast on the GBs and degraded potential uniformity on grain surfaces, resulting from the surface defects/charges of the low-quality film. In contrast, the potential image on an improved high-quality film with the same wide bandgap shows significantly improved GB potential contrast and surface potential uniformity, indicating that the effect of surface defects is critical when examining GB charging using surface potential data. In addition, we discuss the effect of the SKPFM setup on the validity of potential measurement, to exclude possible artifacts due to improper SKPFM setups. The SKPFM results were corroborated by using SCM measurements on the films with a CdS buffer layer. The SCM image shows clear GB contrast, indicating different electrical impedance on the GB from the grain surface. Further, we found that the GB contrast disappeared when the CdS window layer was deposited after the CIGS film was exposed extensively to ambient, which was caused by the creation of CIGS surface defects by the ambient exposure.

  11. Approximations of very weak solutions to boundary-value problems.

    SciTech Connect (OSTI)

    Berggren, Martin Olof

    2003-03-01

    Standard weak solutions to the Poisson problem on a bounded domain have square-integrable derivatives, which limits the admissible regularity of inhomogeneous data. The concept of solution may be further weakened in order to define solutions when data is rough, such as for inhomogeneous Dirichlet data that is only square-integrable over the boundary. Such very weak solutions satisfy a nonstandard variational form (u, v) = G(v). A Galerkin approximation combined with an approximation of the right-hand side G defines a finite-element approximation of the very weak solution. Applying conforming linear elements leads to a discrete solution equivalent to the text-book finite-element solution to the Poisson problem in which the boundary data is approximated by L{sub 2}-projections. The L{sub 2} convergence rate of the discrete solution is O(h{sub s}) for some s {element_of} (0,1/2) that depends on the shape of the domain, asserting a polygonal (two-dimensional) or polyhedral (three-dimensional) domain without slits and (only) square-integrable boundary data.

  12. Boundaries for martensitic transition of 7Li under pressure

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

    Schaeffer, Anne Marie; Cai, Weizhao; Olejnik, Ella; Molaison, Jamie J.; Sinogeikin, Stanislav; dos Santos, Antonio M.; Deemyad, Shanti

    2015-08-14

    We report that physical properties of lithium under extreme pressures continuously reveal unexpected features. These include a sequence of structural transitions to lower symmetry phases, metal-insulator-metal transition, superconductivity with one of the highest elemental transition temperatures, and a maximum followed by a minimum in its melting line. The instability of the bcc structure of lithium is well established by the presence of a temperature-driven martensitic phase transition. The boundaries of this phase, however, have not been previously explored above 3 GPa. All higher pressure phase boundaries are either extrapolations or inferred based on indirect evidence. Here we explore the pressuremore » dependence of the martensitic transition of lithium up to 7 GPa using a combination of neutron and X-ray scattering. We find a rather unexpected deviation from the extrapolated boundaries of the hR3 phase of lithium. Furthermore, there is evidence that, above ~3 GPa, once in fcc phase, lithium does not undergo a martensitic transition.« less

  13. Assessment of local deformation using EBSD: Quantification of local damage at grain boundaries

    SciTech Connect (OSTI)

    Kamaya, Masayuki

    2012-04-15

    Electron backscatter diffraction (EBSD) in conjunction with scanning electron microscopy was used to assess localization of the local misorientation to grain boundary. In order to quantify the degree of localization, a parameter, which was referred to as the grain boundary local misorientation, was proposed. Through crystal orientation measurements using deformed Type 316 stainless steel, it was shown that the grain boundary local misorientation increased with the applied plastic strain. Particularly, at several grain boundaries, the grain boundary local misorientation was more than 3 times the local misorientation averaged for the whole area. Surface observations revealed that the large local misorientation near the grain boundaries was attributed to the impeded slip steps rather than the number of slip steps observed on the surface. The magnitude of the grain boundary local misorientation had a week correlation with grain boundary length or grain boundary misorientation, and no correlation was found for twin boundaries. Finally, it was shown that the maximum grain boundary local misorientation could be estimated statistically, and the estimated maximum value for the specimen surface with an area of 80 mm{sup 2} was 10.6 times the averaged value. - Highlights: Black-Right-Pointing-Pointer The grain boundary local misorientation was proposed. Black-Right-Pointing-Pointer The maximum grain boundary local misorientation could be estimated statistically. Black-Right-Pointing-Pointer The large local misorientation was attributed to the impeded slip steps.

  14. Cryogenic target system for hydrogen layering

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

    Parham, T.; Kozioziemski, B.; Atkinson, D.; Baisden, P.; Bertolini, L.; Boehm, K; Chernov, A.; Coffee, K.; Coffield, F.; Dylla-Spears, R.; et al

    2015-11-24

    Here, a cryogenic target positioning system was designed and installed on the National Ignition Facility (NIF) target chamber. This instrument incorporates the ability to fill, form, and characterize the NIF targets with hydrogen isotopes needed for ignition experiments inside the NIF target bay then transport and position them in the target chamber. This effort brought to fruition years of research in growing and metrologizing high-quality hydrogen fuel layers and landed it in an especially demanding operations environment in the NIF facility. D-T (deuterium-tritium) layers for NIF ignition experiments have extremely tight specifications and must be grown in a very highlymore » constrained environment: a NIF ignition target inside a cryogenic target positioner inside the NIF target bay. Exquisite control of temperature, pressure, contaminant level, and thermal uniformity are necessary throughout seed formation and layer growth to create an essentially-groove-free single crystal layer.« less

  15. Layered solid sorbents for carbon dioxide capture

    DOE Patents [OSTI]

    Li, Bingyun; Jiang, Bingbing; Gray, McMahan L; Fauth, Daniel J; Pennline, Henry W; Richards, George A

    2014-11-18

    A solid sorbent for the capture and the transport of carbon dioxide gas is provided having at least one first layer of a positively charged material that is polyethylenimine or poly(allylamine hydrochloride), that captures at least a portion of the gas, and at least one second layer of a negatively charged material that is polystyrenesulfonate or poly(acryclic acid), that transports the gas, wherein the second layer of material is in juxtaposition to, attached to, or crosslinked with the first layer for forming at least one bilayer, and a solid substrate support having a porous surface, wherein one or more of the bilayers is/are deposited on the surface of and/or within the solid substrate. A method of preparing and using the solid sorbent is provided.

  16. Counting molecular-beam grown graphene layers

    SciTech Connect (OSTI)

    Plaut, Annette S.; Wurstbauer, Ulrich; Pinczuk, Aron; Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York 10027 ; Garcia, Jorge M.; Pfeiffer, Loren N.

    2013-06-17

    We have used the ratio of the integrated intensity of graphene's Raman G peak to that of the silicon substrate's first-order optical phonon peak, accurately to determine the number of graphene layers across our molecular-beam (MB) grown graphene films. We find that these results agree well both, with those from our own exfoliated single and few-layer graphene flakes, and with the results of Koh et al.[ACS Nano 5, 269 (2011)]. We hence distinguish regions of single-, bi-, tri-, four-layer, etc., graphene, consecutively, as we scan coarsely across our MB-grown graphene. This is the first, but crucial, step to being able to grow, by such molecular-beam-techniques, a specified number of large-area graphene layers, to order.

  17. Cermet layer for amorphous silicon solar cells

    DOE Patents [OSTI]

    Hanak, Joseph J.

    1979-01-01

    A transparent high work function metal cermet forms a Schottky barrier in a Schottky barrier amorphous silicon solar cell and adheres well to the P+ layer in a PIN amorphous silicon solar cell.

  18. Multi-layer waste containment barrier

    DOE Patents [OSTI]

    Smith, Ann Marie; Gardner, Bradley M.; Nickelson, David F.

    1999-01-01

    An apparatus for constructing an underground containment barrier for containing an in-situ portion of earth. The apparatus includes an excavating device for simultaneously (i) excavating earthen material from beside the in-situ portion of earth without removing the in-situ portion and thereby forming an open side trench defined by opposing earthen sidewalls, and (ii) excavating earthen material from beneath the in-situ portion of earth without removing the in-situ portion and thereby forming a generally horizontal underground trench beneath the in-situ portion defined by opposing earthen sidewalls. The apparatus further includes a barrier-forming device attached to the excavating device for simultaneously forming a side barrier within the open trench and a generally horizontal, multi-layer barrier within the generally horizontal trench. The multi-layer barrier includes at least a first layer and a second layer.

  19. ARM - Data Announcements Article

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

    5, 2014 [Data Announcements] Ceilometer Derived Planetary Boundary Layer Height Datastream Available Bookmark and Share At the 2012 ASR Science Team Meeting, this comparison received positive feedback from researchers. At the 2012 ASR Science Team Meeting, this comparison received positive feedback from researchers. Planetary Boundary Layer (PBL) height data are now being collected at ARM sites and mobile facilities using an enhanced gradient method algorithm from the Vaisala Ceilometers

  20. Optical devices featuring nonpolar textured semiconductor layers

    DOE Patents [OSTI]

    Moustakas, Theodore D; Moldawer, Adam; Bhattacharyya, Anirban; Abell, Joshua

    2013-11-26

    A semiconductor emitter, or precursor therefor, has a substrate and one or more textured semiconductor layers deposited onto the substrate in a nonpolar orientation. The textured layers enhance light extraction, and the use of nonpolar orientation greatly enhances internal quantum efficiency compared to conventional devices. Both the internal and external quantum efficiencies of emitters of the invention can be 70-80% or higher. The invention provides highly efficient light emitting diodes suitable for solid state lighting.

  1. Optical devices featuring textured semiconductor layers

    DOE Patents [OSTI]

    Moustakas, Theodore D.; Cabalu, Jasper S.

    2011-10-11

    A semiconductor sensor, solar cell or emitter, or a precursor therefor, has a substrate and one or more textured semiconductor layers deposited onto the substrate. The textured layers enhance light extraction or absorption. Texturing in the region of multiple quantum wells greatly enhances internal quantum efficiency if the semiconductor is polar and the quantum wells are grown along the polar direction. Electroluminescence of LEDs of the invention is dichromatic, and results in variable color LEDs, including white LEDs, without the use of phosphor.

  2. Optical devices featuring textured semiconductor layers

    DOE Patents [OSTI]

    Moustakas, Theodore D.; Cabalu, Jasper S.

    2012-08-07

    A semiconductor sensor, solar cell or emitter, or a precursor therefor, has a substrate and one or more textured semiconductor layers deposited onto the substrate. The textured layers enhance light extraction or absorption. Texturing in the region of multiple quantum wells greatly enhances internal quantum efficiency if the semiconductor is polar and the quantum wells are grown along the polar direction. Electroluminescence of LEDs of the invention is dichromatic, and results in variable color LEDs, including white LEDs, without the use of phosphor.

  3. The Independence Heights House

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

    1.7 Percentage of Population Below the Poverty Level 41.6% Houston- Demographics ... 1.2 Percentage of Population Below the Poverty Level 23.8% CONTEXT CONTEXT DESIGN GOALS ...

  4. Method of depositing epitaxial layers on a substrate

    SciTech Connect (OSTI)

    Goyal, Amit

    2003-12-30

    An epitaxial article and method for forming the same includes a substrate having a textured surface, and an electrochemically deposited substantially single orientation epitaxial layer disposed on and in contact with the textured surface. The epitaxial article can include an electromagnetically active layer and an epitaxial buffer layer. The electromagnetically active layer and epitaxial buffer layer can also be deposited electrochemically.

  5. PERCOLATION ON GRAIN BOUNDARY NETWORKS: APPLICATION TO FISSION GAS RELEASE IN NUCLEAR FUELS

    SciTech Connect (OSTI)

    Paul C. Millett

    2012-02-01

    The percolation behavior of grain boundary networks is characterized in two- and three-dimensional lattices with circular macroscale cross-sections that correspond to nuclear fuel elements. The percolation of gas bubbles on grain boundaries, and the subsequent percolation of grain boundary networks is the primary mechanism of fission gas release from nuclear fuels. Both radial cracks and radial gradients in grain boundary property distributions are correlated with the fraction of grain boundaries vented to the free surfaces. Our results show that cracks surprisingly do not significantly increase the percolation of uniform grain boundary networks. However, for networks with radial gradients in boundary properties, the cracks can considerably raise the vented grain boundary content.

  6. Grain boundary plane orientation fundamental zones and structure-property relationships

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

    Homer, Eric R.; Patala, Srikanth; Priedeman, Jonathan L.

    2015-10-26

    Grain boundary plane orientation is a profoundly important determinant of character in polycrystalline materials that is not well understood. This work demonstrates how boundary plane orientation fundamental zones, which capture the natural crystallographic symmetries of a grain boundary, can be used to establish structure-property relationships. Using the fundamental zone representation, trends in computed energy, excess volume at the grain boundary, and temperature-dependent mobility naturally emerge and show a strong dependence on the boundary plane orientation. Analysis of common misorientation axes even suggests broader trends of grain boundary energy as a function of misorientation angle and plane orientation. Due to themore » strong structure-property relationships that naturally emerge from this work, boundary plane fundamental zones are expected to simplify analysis of both computational and experimental data. This standardized representation has the potential to significantly accelerate research in the topologically complex and vast five-dimensional phase space of grain boundaries.« less

  7. Grain boundary plane orientation fundamental zones and structure-property relationships

    SciTech Connect (OSTI)

    Homer, Eric R.; Patala, Srikanth; Priedeman, Jonathan L.

    2015-10-26

    Grain boundary plane orientation is a profoundly important determinant of character in polycrystalline materials that is not well understood. This work demonstrates how boundary plane orientation fundamental zones, which capture the natural crystallographic symmetries of a grain boundary, can be used to establish structure-property relationships. Using the fundamental zone representation, trends in computed energy, excess volume at the grain boundary, and temperature-dependent mobility naturally emerge and show a strong dependence on the boundary plane orientation. Analysis of common misorientation axes even suggests broader trends of grain boundary energy as a function of misorientation angle and plane orientation. Due to the strong structure-property relationships that naturally emerge from this work, boundary plane fundamental zones are expected to simplify analysis of both computational and experimental data. This standardized representation has the potential to significantly accelerate research in the topologically complex and vast five-dimensional phase space of grain boundaries.

  8. The Kastler-Kalau-Walze type theorem for six-dimensional manifolds with boundary

    SciTech Connect (OSTI)

    Wang, Jian; Wang, Yong E-mail: wangy581@nenu.edu.cn

    2015-05-15

    In this paper, we define lower dimensional volumes of spin manifolds with boundary. We compute the lower dimensional volume V ol{sub 6}{sup (1,3)} for 6-dimensional spin manifolds with boundary and derive the gravity on boundary from the noncommutative residue associated with Dirac operators. For 6-dimensional manifolds with boundary, we also get a Kastler-Kalau-Walze type theorem for a general fourth order operator.

  9. Barrier height of Pt-In{sub x}Ga{sub 1-x}N (0{<=}x{<=}0.5) nanowire Schottky diodes

    SciTech Connect (OSTI)

    Guo Wei; Banerjee, Animesh; Zhang Meng; Bhattacharya, Pallab

    2011-05-02

    The barrier height of Schottky diodes made on In{sub x}Ga{sub 1-x}N nanowires have been determined from capacitance-voltage measurements. The nanowires were grown undoped on n-type (001) silicon substrates by plasma-assisted molecular beam epitaxy. The length, diameter and density of the nanowires are {approx}1 {mu}m, 20 nm, and 1x10{sup 11} cm{sup -2}. The Schottky contact was made on the top surface of the nanowires with Pt after planarizing with parylene. The measured barrier height {Phi}{sub B} varies from 1.4 eV (GaN) to 0.44 eV (In{sub 0.5}Ga{sub 0.5}N) and agrees well with the ideal barrier heights in the Schottky limit.

  10. Selective layer disordering in III-nitrides with a capping layer

    DOE Patents [OSTI]

    Wierer, Jr., Jonathan J.; Allerman, Andrew A.

    2016-06-14

    Selective layer disordering in a doped III-nitride superlattice can be achieved by depositing a dielectric capping layer on a portion of the surface of the superlattice and annealing the superlattice to induce disorder of the layer interfaces under the uncapped portion and suppress disorder of the interfaces under the capped portion. The method can be used to create devices, such as optical waveguides, light-emitting diodes, photodetectors, solar cells, modulators, laser, and amplifiers.

  11. Controlling potential barrier height by changing V-shaped pit size and the effect on optical and electrical properties for InGaN/GaN based light-emitting diodes

    SciTech Connect (OSTI)

    Okada, Narihito Kashihara, Hiroyuki; Sugimoto, Kohei; Yamada, Yoichi; Tadatomo, Kazuyuki

    2015-01-14

    The internal quantum efficiency (IQE) of InGaN/GaN multiple quantum wells (MQWs) with blue light emission was improved by inserting an InGaN/GaN superlattice (SL) beneath the MQWs. While the SL technique is useful for improving the light-emitting diode (LED) performance, its effectiveness from a multilateral point of view requires investigation. V-shaped pits (V-pits), which generate a potential barrier and screen the effect of the threading dislocation, are one of the candidates for increasing the light emission efficiency of LEDs exceptionally. In this research, we investigated the relationship between the V-pit and SL and revealed that the V-pit diameter is strongly correlated with the IQE by changing the number of SL periods. Using scanning near-field optical microscopy and photoluminescence measurements, we demonstrated the distinct presence of the potential barrier formed by the V-pits around the dislocations. The relationship between the V-pit and the number of SL periods resulted in changing the potential barrier height, which is related to the V-pit diameter determined by the number of SL periods. In addition, we made an attempt to insert pit expansion layers (PELs) composed of combination of SL and middle temperature grown GaN layer instead of only SL structure. As a result of the evaluation of LEDs using SL or PEL, the EL intensity was strongly related to pit diameter regardless of the structures to form the V-pits. In addition, it was clear that larger V-pits reduce the efficiency droop, which is considered to be suppression of the carrier loss at high injection current.

  12. Characterization of CZTSSe photovoltaic device with an atomic layer-deposited passivation layer

    SciTech Connect (OSTI)

    Wu, Wei Cao, Yanyan; Caspar, Jonathan V.; Guo, Qijie; Johnson, Lynda K.; Mclean, Robert S.; Malajovich, Irina; Choudhury, Kaushik Roy

    2014-07-28

    We describe a CZTSSe (Cu{sub 2}ZnSn(S{sub 1−x},Se{sub x}){sub 4}) photovoltaic (PV) device with an ALD (atomic layer deposition) coated buffer dielectric layer for CZTSSe surface passivation. An ALD buffer layer, such as TiO{sub 2}, can be applied in order to reduce the interface recombination and improve the device's open-circuit voltage. Detailed characterization data including current-voltage, admittance spectroscopy, and capacitance profiling are presented in order to compare the performance of PV devices with and without the ALD layer.

  13. Core and filament formation in magnetized, self-gravitating isothermal layers

    SciTech Connect (OSTI)

    Van Loo, Sven; Keto, Eric; Zhang, Qizhou

    2014-07-01

    We examine the role of the gravitational instability in an isothermal, self-gravitating layer threaded by magnetic fields on the formation of filaments and dense cores. Using a numerical simulation, we follow the non-linear evolution of a perturbed equilibrium layer. The linear evolution of such a layer is described in the analytic work of Nagai et al. We find that filaments and dense cores form simultaneously. Depending on the initial magnetic field, the resulting filaments form either a spiderweb-like network (for weak magnetic fields) or a network of parallel filaments aligned perpendicular to the magnetic field lines (for strong magnetic fields). Although the filaments are radially collapsing, the density profile of their central region (up to the thermal scale height) can be approximated by a hydrodynamical equilibrium density structure. Thus, the magnetic field does not play a significant role in setting the density distribution of the filaments. The density distribution outside of the central region deviates from the equilibrium. The radial column density distribution is then flatter than the expected power law of r {sup 4} and similar to filament profiles observed with Herschel. Our results do not explain the near constant filament width of ?0.1pc. However, our model does not include turbulent motions. It is expected that the accretion-driven amplification of these turbulent motions provides additional support within the filaments against gravitational collapse. Finally, we interpret the filamentary network of the massive star forming complex G14.225-0.506 in terms of the gravitational instability model and find that the properties of the complex are consistent with being formed out of an unstable layer threaded by a strong, parallel magnetic field.

  14. Indoor air pollution from portable kerosene-fired space heaters. [Effects of wick height and fuel consumption rate

    SciTech Connect (OSTI)

    Traynor, G.W.; Apte, M.G.; Dillworth, J.F.; Grimsrud, D.T.

    1983-02-01

    Indoor use of unvented combustion appliances is known to cause an increase in indoor air pollutant levels. Laboratory tests were conducted on radiant and convective portable kerosene-fired space heaters to identify the pollutants they emit and to determine their emission rates. Laboratory-derived CO and NO/sub 2/ emission rates from unvented portable kerosense-fired space heaters are summarized and the effect of wick height and fuel consumption rate on CO and NO/sub 2/ emissions is given. Pollutant concentration profiles resulting from the use of kerosene heaters in a 27m/sup 3/ environmental chamber and a 240m/sup 3/ house are presented. When such heaters are operated for one hour in a 27m/sup 3/ chamber with 0.4 air changes per hour, the resultant CO/sub 2/ concentrations are well above the U.S. occupational standard, and NO/sub 2/ concentrations are well above California's short-term outdoor standard. Further data on parameters such as heater usage patterns and air exchange rates are needed to determine the actual pollutant exposure that kerosene heater users experience.

  15. Effects of surface properties on barrier height and barrier inhomogeneities of platinum contacts to n-type 4H-SiC

    SciTech Connect (OSTI)

    Huang Lingqin; Li Shijuan; Wang Dejun [School of Electronic Science and Technology, Faculty of Electronic Information and Electrical Engineering, Dalian University of Technology, Dalian 116024 (China); Qin Fuwen [State Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Ministry of Education), Dalian University of Technology, Dalian 116024 (China)

    2013-07-15

    We investigated the Schottky barrier of Pt/4H-SiC contact as a function of 4H-SiC surface properties which effectively controlled by electronic cyclotron resonance hydrogen plasma pretreatment for different periods and annealing. It is found that the effective barrier height monotonically increases with decreasing the degree of Fermi level pinning. Electrically homogeneous contacts are observed when the Fermi level (FL) is 'pinned (Bardeen limit)' and 'free-pinned (Schottky limit).' However, a partial pinning of FL leads to Gaussian distribution of inhomogeneous barrier height. These results could be correlated with changes in the magnitude and spatial distribution of surface state density after different pretreatments.

  16. Organic light emitting device having multiple separate emissive layers

    DOE Patents [OSTI]

    Forrest, Stephen R. (Ann Arbor, MI)

    2012-03-27

    An organic light emitting device having multiple separate emissive layers is provided. Each emissive layer may define an exciton formation region, allowing exciton formation to occur across the entire emissive region. By aligning the energy levels of each emissive layer with the adjacent emissive layers, exciton formation in each layer may be improved. Devices incorporating multiple emissive layers with multiple exciton formation regions may exhibit improved performance, including internal quantum efficiencies of up to 100%.

  17. P-SV conversions at a shallow boundary beneath Campi Flegrei caldera (Italy) - evidence for the magma chamber

    SciTech Connect (OSTI)

    Ferrucci, F.; Hirn, A.; De Natale, G.; Virieux, J.; Mirabile, L. Inst. de Physique du Globe, Paris Osservatorio Vesuviano, Naples CNRS, Inst. de Geodynamique, Valbonne Ist. Universitario Navale, Naples )

    1992-10-01

    Seismograms from an active seismic experiment carried out at Campi Flegrei caldera (near Naples, Italy), show a large-amplitude SV-polarized shear wave, following by less than 1.5-s P waves reflected at wide angle from a deep crustal interface. Early arriving SV-polarized waves, with the same delay to direct P waves, are also observed in seismograms from a regional 280 km-deep, magnitude 5.1 earthquake. Such short delays of S to P waves are consistent with a P-SV conversion on transmission occurring at a shallow boundary beneath the receivers. The large amplitude of the converted-SV phase, along with that the P waves are near vertical, requires a boundary separating a very low rigidity layer from the upper caldera fill. The converted phases are interpreted as a seismic marker of a magma chamber. The top of this magma chamber is located slightly deeper than the deepest earthquakes observed during the 1982-1984 unrest of Campi Flegrei. 8 refs.

  18. Microstructural and chemical evolution near anode triple phase boundary in Ni/YSZ solid oxide fuel cells

    SciTech Connect (OSTI)

    Chen, Yun; Chen, Song; Hackett, Gregory; Finklea, Harry; Song, Xueyan; Gerdes, Kirk

    2011-12-12

    In this study, we report the micro-structural and chemical evolution of anode grain boundaries and triple phase boundary (TPB) junctions of Ni/YSZ anode supported solid oxide fuel cells. A NiO phase was found to develop along the Ni/YSZ interfaces extending to TPBs in the operated cells. The thickness of the NiO ribbon phase remains constant at ~ 5 nm in hydrogen for operating durations up to 540 h. When operating on synthesis gas, an increase in interphase thickness was observed from ~ 11 nm for 24 h of operation to ~ 51 nm for 550 h of operation. YSZ phases are observed to be stable in H{sub 2} over 540 h of operation. However, for the cell operated in syngas for 550 h, a 510 nm tetragonal YSZ (t-YSZ) interfacial layer was identified that originated from the Ni/YSZ interfaces. Yttrium species seem to segregate to the interfaces during operation, leading to the formation of t-YSZ in the Y-depleted regions.

  19. Inorganic dual-layer microporous supported membranes

    DOE Patents [OSTI]

    Brinker, C. Jeffrey; Tsai, Chung-Yi; Lu, Yungfeng

    2003-03-25

    The present invention provides for a dual-layer inorganic microporous membrane capable of molecular sieving, and methods for production of the membranes. The inorganic microporous supported membrane includes a porous substrate which supports a first inorganic porous membrane having an average pore size of less than about 25 .ANG. and a second inorganic porous membrane coating the first inorganic membrane having an average pore size of less than about 6 .ANG.. The dual-layered membrane is produced by contacting the porous substrate with a surfactant-template polymeric sol, resulting in a surfactant sol coated membrane support. The surfactant sol coated membrane support is dried, producing a surfactant-templated polymer-coated substrate which is calcined to produce an intermediate layer surfactant-templated membrane. The intermediate layer surfactant-templated membrane is then contacted with a second polymeric sol producing a polymeric sol coated substrate which is dried producing an inorganic polymeric coated substrate. The inorganic polymeric coated substrate is then calcined producing an inorganic dual-layered microporous supported membrane in accordance with the present invention.

  20. Membrane catalyst layer for fuel cells

    DOE Patents [OSTI]

    Wilson, Mahlon S.

    1993-01-01

    A gas reaction fuel cell incorporates a thin catalyst layer between a solid polymer electrolyte (SPE) membrane and a porous electrode backing. The catalyst layer is preferably less than about 10 .mu.m in thickness with a carbon supported platinum catalyst loading less than about 0.35 mgPt/cm.sup.2. The film is formed as an ink that is spread and cured on a film release blank. The cured film is then transferred to the SPE membrane and hot pressed into the surface to form a catalyst layer having a controlled thickness and catalyst distribution. Alternatively, the catalyst layer is formed by applying a Na.sup.+ form of a perfluorosulfonate ionomer directly to the membrane, drying the film at a high temperature, and then converting the film back to the protonated form of the ionomer. The layer has adequate gas permeability so that cell performance is not affected and has a density and particle distribution effective to optimize proton access to the catalyst and electronic continuity for electron flow from the half-cell reaction occurring at the catalyst.

  1. Technoeconomic Boundary Analysis of Biological Pathways to Hydrogen Production

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

    Subcontract Report NREL/SR-560-46674 September 2009 Technoeconomic Boundary Analysis of Biological Pathways to Hydrogen Production March 27, 2008 - August 31, 2009 B.D. James, G.N. Baum, J. Perez, and K.N. Baum Directed Technologies, Inc. Arlington, Virginia National Renewable Energy Laboratory 1617 Cole Boulevard, Golden, Colorado 80401-3393 303-275-3000 * www.nrel.gov NREL is a national laboratory of the U.S. Department of Energy Office of Energy Efficiency and Renewable Energy Operated by the

  2. Thermopower Enhancement by Fractional Layer Control in 2D Oxide...

    Office of Scientific and Technical Information (OSTI)

    Thermopower Enhancement by Fractional Layer Control in 2D Oxide Superlattices Citation Details In-Document Search Title: Thermopower Enhancement by Fractional Layer Control in 2D ...

  3. Application of Analytical Heat Transfer Models of Multi-layered...

    Office of Scientific and Technical Information (OSTI)

    multi-layered cylindrical solution to simulate the temperature response of a deep geologic radioactive waste repository with multi-layered natural and engineered...

  4. Spatial atomic layer deposition on flexible substrates using...

    Office of Scientific and Technical Information (OSTI)

    Spatial atomic layer deposition on flexible substrates using a modular rotating cylinder reactor Citation Details In-Document Search Title: Spatial atomic layer deposition on...

  5. Analysis of thomsen parameters for finely layered VTI media ...

    Office of Scientific and Technical Information (OSTI)

    Conference: Analysis of thomsen parameters for finely layered VTI media Citation Details In-Document Search Title: Analysis of thomsen parameters for finely layered VTI media ...

  6. Controlled Covalent Modification of Epitaxial Single Layer Graphene...

    Office of Scientific and Technical Information (OSTI)

    Journal Article: Controlled Covalent Modification of Epitaxial Single Layer Graphene on ... Title: Controlled Covalent Modification of Epitaxial Single Layer Graphene on 6H-SiC ...

  7. Buffer layer for thin film structures (Patent) | DOEPatents

    Office of Scientific and Technical Information (OSTI)

    A superconducting article can include a composite structure including an outermost layer of magnesium oxide, a buffer layer of strontium titanate or a mixture of strontium titanate ...

  8. Solvothermal Thin Film Deposition of Electron Blocking Layers...

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

    Solvothermal Thin Film Deposition of Electron Blocking Layers Home > Research > ANSER Research Highlights > Solvothermal Thin Film Deposition of Electron Blocking Layers...

  9. Graphene-silicon layered structures on single-crystalline Ir...

    Office of Scientific and Technical Information (OSTI)

    Accepted Manuscript: Graphene-silicon layered structures on single-crystalline Ir(111) thin films Prev Next Title: Graphene-silicon layered structures on single-crystalline...

  10. Thermal Multi-layer Coating Analysis | Argonne National Laboratory

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

    Thermal Multi-layer Coating Analysis Key to Argonne's thermal multi-layer analysis method is the numerical algorithm used for automated analysis of thermal imaging data for...

  11. Facile oxygen intercalation between full layer graphene and Ru...

    Office of Scientific and Technical Information (OSTI)

    Facile oxygen intercalation between full layer graphene and Ru(0001) under ambient ... Title: Facile oxygen intercalation between full layer graphene and Ru(0001) under ambient ...

  12. Atomic Layer Deposition of Metal Sulfide Materials | Argonne...

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

    Atomic Layer Deposition of Metal Sulfide Materials Title Atomic Layer Deposition of Metal Sulfide Materials Publication Type Journal Article Year of Publication 2015 Authors...

  13. Exploration of the mechanisms of temperature-dependent grain boundary mobility: Search for the common origin of ultrafast grain boundary motion

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

    O’Brien, C. J.; Foiles, S. M.

    2016-04-19

    The temperature dependence of grain boundary mobility is complex, varied, and rarely fits ideal Arrhenius behavior. This work presents a series of case studies of planar grain boundaries in a model FCC system that were previously demonstrated to exhibit a variety of temperature-dependent mobility behaviors. It is demonstrated that characterization of the mobility versus temperature plots is not sufficient to predict the atomic motion mechanism of the grain boundaries. Herein, the temperature-dependent motion and atomistic motion mechanisms of planar grain boundaries are driven by a synthetic, orientation-dependent, driving force. The systems studied include CSL boundaries with Σ values of 5,more » 7, and 15, including both symmetric and asymmetric boundaries. These boundaries represent a range of temperature-dependent trends including thermally activated, antithermal, and roughening behaviors. Examining the atomic-level motion mechanisms of the thermally activated boundaries reveals that each involves a complex shuffle, and at least one atom that changes the plane it resides on. The motion mechanism of the antithermal boundary is qualitatively different and involves an in-plane coordinated shuffle that rotates atoms about a fixed atom lying on a point in the coincident site lattice. Furthermore, this provides a mechanistic reason for the observed high mobility, even at low temperatures, which is due to the low activation energy needed for such motion. However, it will be demonstrated that this mechanism is not universal, or even common, to other boundaries exhibiting non-thermally activated motion. This work concludes that no single atomic motion mechanism is sufficient to explain the existence of non-thermally activated boundary motion.« less

  14. Crystallographic Characteristics of Grain Boundaries in Dense Yttria-Stabilized Zirconia

    SciTech Connect (OSTI)

    Lam Helmick; Shen J. Dillon; Kirk Gerdes; Randall Gemmen; Gregory S. Rohrer; Sridhar Seetharaman; Paul A. Salvador

    2010-04-01

    Grain-boundary plane, misorientation angle, grain size, and grain-boundary energy distributions were quantified using electron backscatter diffraction data for dense polycrystalline yttria-stabilized zirconia, to understand interfacial crystallography in solid oxide fuel cells. Tape-cast samples were sintered at 14501C for 4 h and annealed for at least 100 h between 8001C and 16501C. Distributions obtained from both three-dimensional (3D) reconstructions and stereological analyses of 2D sections demonstrated that the (100) boundary planes {(111)} have relative areas larger {smaller} than expected in a random distribution, and that the boundary plane distribution is inversely correlated to the boundary energy distribution.

  15. Process for depositing Cr-bearing layer

    DOE Patents [OSTI]

    Ellis, Timothy W.; Lograsso, Thomas A.; Eshelman, Mark A.

    1995-05-09

    A method of applying a Cr-bearing layer to a substrate, comprises introducing an organometallic compound, in vapor or solid powder form entrained in a carrier gas to a plasma of an inductively coupled plasma torch or device to thermally decompose the organometallic compound and contacting the plasma and the substrate to be coated so as to deposit the Cr-bearing layer on the substrate. A metallic Cr, Cr alloy or Cr compound such as chromium oxide, nitride and carbide can be provided on the substrate. Typically, the organometallic compound is introduced to an inductively coupled plasma torch that is disposed in ambient air so to thermally decompose the organometallic compound in the plasma. The plasma is directed at the substrate to deposit the Cr-bearing layer or coating on the substrate.

  16. Growth of oxide exchange bias layers

    DOE Patents [OSTI]

    Chaiken, Alison; Michel, Richard P.

    1998-01-01

    An oxide (NiO, CoO, NiCoO) antiferromagnetic exchange bias layer produced by ion beam sputtering of an oxide target in pure argon (Ar) sputtering gas, with no oxygen gas introduced into the system. Antiferromagnetic oxide layers are used, for example, in magnetoresistive readback heads to shift the hysteresis loops of ferromagnetic films away from the zero field axis. For example, NiO exchange bia layers have been fabricated using ion beam sputtering of an NiO target using Ar ions, with the substrate temperature at 200.degree. C., the ion beam voltage at 1000V and the beam current at 20 mA, with a deposition rate of about 0.2 .ANG./sec. The resulting NiO film was amorphous.

  17. Process for depositing Cr-bearing layer

    DOE Patents [OSTI]

    Ellis, T.W.; Lograsso, T.A.; Eshelman, M.A.

    1995-05-09

    A method of applying a Cr-bearing layer to a substrate, comprises introducing an organometallic compound, in vapor or solid powder form entrained in a carrier gas to a plasma of an inductively coupled plasma torch or device to thermally decompose the organometallic compound and contacting the plasma and the substrate to be coated so as to deposit the Cr-bearing layer on the substrate. A metallic Cr, Cr alloy or Cr compound such as chromium oxide, nitride and carbide can be provided on the substrate. Typically, the organometallic compound is introduced to an inductively coupled plasma torch that is disposed in ambient air so to thermally decompose the organometallic compound in the plasma. The plasma is directed at the substrate to deposit the Cr-bearing layer or coating on the substrate. 7 figs.

  18. Growth of oxide exchange bias layers

    DOE Patents [OSTI]

    Chaiken, A.; Michel, R.P.

    1998-07-21

    An oxide (NiO, CoO, NiCoO) antiferromagnetic exchange bias layer produced by ion beam sputtering of an oxide target in pure argon (Ar) sputtering gas, with no oxygen gas introduced into the system. Antiferromagnetic oxide layers are used, for example, in magnetoresistive readback heads to shift the hysteresis loops of ferromagnetic films away from the zero field axis. For example, NiO exchange bias layers have been fabricated using ion beam sputtering of an NiO target using Ar ions, with the substrate temperature at 200 C, the ion beam voltage at 1000V and the beam current at 20 mA, with a deposition rate of about 0.2 {angstrom}/sec. The resulting NiO film was amorphous. 4 figs.

  19. Excess Oxygen Defects in Layered Cuprates

    DOE R&D Accomplishments [OSTI]

    Lightfoot, P.; Pei, S. Y.; Jorgensen, J. D.; Manthiram, A.; Tang, X. X.; Goodenough, J. B.

    1990-09-01

    Neutron powder diffraction has been used to study the oxygen defect chemistry of two non-superconducting layered cuprates, La{sub 1. 25}Dy{sub 0.75}Cu{sub 3.75}F{sub 0.5}, having a T{sup {asterisk}}- related structure, and La{sub 1.85}Sr{sub 1.15}Cu{sub 2}O{sub 6.25}, having a structure related to that of the newly discovered double-layer superconductor La{sub 2-x}Sr{sub x}CaCu{sub 2}O{sub 6}. The role played by oxygen defects in determining the superconducting properties of layered cuprates is discussed.

  20. Permafrost Active Layer Seismic Interferometry Experiment (PALSIE).

    SciTech Connect (OSTI)

    Abbott, Robert; Knox, Hunter Anne; James, Stephanie; Lee, Rebekah; Cole, Chris

    2016-01-01

    We present findings from a novel field experiment conducted at Poker Flat Research Range in Fairbanks, Alaska that was designed to monitor changes in active layer thickness in real time. Results are derived primarily from seismic data streaming from seven Nanometric Trillium Posthole seismometers directly buried in the upper section of the permafrost. The data were evaluated using two analysis methods: Horizontal to Vertical Spectral Ratio (HVSR) and ambient noise seismic interferometry. Results from the HVSR conclusively illustrated the method's effectiveness at determining the active layer's thickness with a single station. Investigations with the multi-station method (ambient noise seismic interferometry) are continuing at the University of Florida and have not yet conclusively determined active layer thickness changes. Further work continues with the Bureau of Land Management (BLM) to determine if the ground based measurements can constrain satellite imagery, which provide measurements on a much larger spatial scale.

  1. Buffer layers on metal alloy substrates for superconducting tapes

    DOE Patents [OSTI]

    Jia, Quanxi; Foltyn, Stephen R.; Arendt, Paul N.; Groves, James R.

    2004-10-05

    An article including a substrate, at least one intermediate layer upon the surface of the substrate, a layer of an oriented cubic oxide material having a rock-salt-like structure upon the at least one intermediate layer, and a layer of a SrRuO.sub.3 buffer material upon the oriented cubic oxide material layer is provided together with additional layers such as a HTS top-layer of YBCO directly upon the layer of a SrRuO.sub.3 buffer material layer. With a HTS top-layer of YBCO upon at least one layer of the SrRuO.sub.3 buffer material in such an article, J.sub.c 's of up to 1.3.times.10.sup.6 A/cm.sup.2 have been demonstrated with projected I.sub.c 's of over 200 Amperes across a sample 1 cm wide.

  2. Turbine exhaust diffuser with region of reduced flow area and outer boundary gas flow

    DOE Patents [OSTI]

    Orosa, John

    2014-03-11

    An exhaust diffuser system and method for a turbine engine. The outer boundary may include a region in which the outer boundary extends radially inwardly toward the hub structure and may direct at least a portion of an exhaust flow in the diffuser toward the hub structure. At least one gas jet is provided including a jet exit located on the outer boundary. The jet exit may discharge a flow of gas downstream substantially parallel to an inner surface of the outer boundary to direct a portion of the exhaust flow in the diffuser toward the outer boundary to effect a radially outward flow of at least a portion of the exhaust gas flow toward the outer boundary to balance an aerodynamic load between the outer and inner boundaries.

  3. Fusion utility in the Knudsen layer

    SciTech Connect (OSTI)

    Davidovits, Seth; Fisch, Nathaniel J.

    2014-09-15

    In inertial confinement fusion, the loss of fast ions from the edge of the fusing hot-spot region reduces the reactivity below its Maxwellian value. The loss of fast ions may be pronounced because of the long mean free paths of fast ions, compared with those of thermal ions. We introduce a fusion utility function to demonstrate essential features of this Knudsen layer effect, in both magnetized and unmagnetized cases. The fusion utility concept is also used to evaluate the restoring reactivity in the Knudsen layer by manipulating fast ions in phase space using waves.

  4. Photovoltaic cell with thin CS layer

    DOE Patents [OSTI]

    Jordan, John F.; Albright, Scot P.

    1994-01-18

    An improved photovoltaic panel and method of forming a photovoltaic panel are disclosed for producing a high efficiency CdS/CdTe photovoltaic cell. The photovoltaic panel of the present invention is initially formed with a substantially thick Cds layer, and the effective thickness of the CdS layer is substantially reduced during regrowth to both form larger diameter CdTe crystals and substantially reduce the effective thickness of the C This invention was made with Government support under Subcontract No. ZL-7-06031-3 awarded by the Department of Energy. The Government has certain rights in this invention.

  5. Fusion Utility in the Knudsen Layer

    SciTech Connect (OSTI)

    Davidovits, Seth; Fisch, Nathaniel J.

    2014-08-01

    In inertial confi nement fusion, the loss of fast ions from the edge of the fusing hot-spot region reduces the reactivity below its Maxwellian value. The loss of fast ions may be pronounced because of the long mean free paths of fast ions, compared to those of thermal ions. We introduce a fusion utility function to demonstrate essential features of this Knudsen layer e ffect, in both magnetized and unmagnetized cases. The fusion utility concept is also used to evaluate restoring the reactivity in the Knudsen layer by manipulating fast ions in phase space using waves.

  6. Optimized boundary driven flows for dynamos in a sphere

    SciTech Connect (OSTI)

    Khalzov, I. V.; Brown, B. P.; Cooper, C. M.; Weisberg, D. B.; Forest, C. B. [Center for Magnetic Self Organization in Laboratory and Astrophysical Plasmas, University of Wisconsin-Madison, 1150 University Avenue, Madison, Wisconsin 53706 (United States)

    2012-11-15

    We perform numerical optimization of the axisymmetric flows in a sphere to minimize the critical magnetic Reynolds number Rm{sub cr} required for dynamo onset. The optimization is done for the class of laminar incompressible flows of von Karman type satisfying the steady-state Navier-Stokes equation. Such flows are determined by equatorially antisymmetric profiles of driving azimuthal (toroidal) velocity specified at the spherical boundary. The model is relevant to the Madison plasma dynamo experiment, whose spherical boundary is capable of differential driving of plasma in the azimuthal direction. We show that the dynamo onset in this system depends strongly on details of the driving velocity profile and the fluid Reynolds number Re. It is found that the overall lowest Rm{sub cr} Almost-Equal-To 200 is achieved at Re Almost-Equal-To 240 for the flow, which is hydrodynamically marginally stable. We also show that the optimized flows can sustain dynamos only in the range Rm{sub cr}

  7. Plasma Transport at the Magnetospheric Flank Boundary. Final report

    SciTech Connect (OSTI)

    Otto, Antonius

    2012-04-23

    Progress is highlighted in these areas: 1. Model of magnetic reconnection induced by three-dimensional Kelvin Helmholtz (KH) modes at the magnetospheric flank boundary; 2. Quantitative evaluation of mass transport from the magnetosheath onto closed geomagnetic field for northward IMF; 3. Comparison of mass transfer by cusp reconnection and Flank Kelvin Helmholtz modes; 4. Entropy constraint and plasma transport in the magnetotail - a new mechanism for current sheet thinning; 5. Test particle model for mass transport onto closed geomagnetic field for northward IMF; 6. Influence of density asymmetry and magnetic shear on (a) the linear and nonlinear growth of 3D Kelvin Helmholtz (KH) modes, and (b) three-dimensional KH mediated mass transport; 7. Examination of entropy and plasma transport in the magnetotail; 8. Entropy change and plasma transport by KH mediated reconnection - mixing and heating of plasma; 9. Entropy and plasma transport in the magnetotail - tail reconnection; and, 10. Wave coupling at the magnetospheric boundary and generation of kinetic Alfven waves.

  8. Physics of grain boundaries in polycrystalline photovoltaic semiconductors

    SciTech Connect (OSTI)

    Yan, Yanfa Yin, Wan-Jian; Wu, Yelong; Shi, Tingting; Paudel, Naba R.; Li, Chen; Poplawsky, Jonathan; Wang, Zhiwei; Moseley, John; Guthrey, Harvey; Moutinho, Helio; Al-Jassim, Mowafak M.; Pennycook, Stephen J.

    2015-03-21

    Thin-film solar cells based on polycrystalline Cu(In,Ga)Se{sub 2} (CIGS) and CdTe photovoltaic semiconductors have reached remarkable laboratory efficiencies. It is surprising that these thin-film polycrystalline solar cells can reach such high efficiencies despite containing a high density of grain boundaries (GBs), which would seem likely to be nonradiative recombination centers for photo-generated carriers. In this paper, we review our atomistic theoretical understanding of the physics of grain boundaries in CIGS and CdTe absorbers. We show that intrinsic GBs with dislocation cores exhibit deep gap states in both CIGS and CdTe. However, in each solar cell device, the GBs can be chemically modified to improve their photovoltaic properties. In CIGS cells, GBs are found to be Cu-rich and contain O impurities. Density-functional theory calculations reveal that such chemical changes within GBs can remove most of the unwanted gap states. In CdTe cells, GBs are found to contain a high concentration of Cl atoms. Cl atoms donate electrons, creating n-type GBs between p-type CdTe grains, forming local p-n-p junctions along GBs. This leads to enhanced current collections. Therefore, chemical modification of GBs allows for high efficiency polycrystalline CIGS and CdTe thin-film solar cells.

  9. Frictional anisotropy under boundary lubrication: effect of surface texture.

    SciTech Connect (OSTI)

    Ajayi, O. O.; Erck, R. A.; Lorenzo-Martin, C.; Fenske, G. R.; Energy Systems

    2009-06-15

    The friction coefficient was measured under boundary lubrication with a ball-on-flat contact configuration in unidirectional sliding. The ball was smooth and hardened 52100 steel. Discs were made from case-carburized and hardened 4620, annealed 1080, and 1018 steels with directionally ground surfaces. A synthetic lubricant of stock polyalphaolefin was used for testing. During testing with each material, a frictional spike was observed whenever the ball slid parallel to the grinding ridge on the disc surface. The average friction coefficient for all tests was about 0.1, which is typical for the boundary lubrication regime. The magnitude of the frictional spikes, which reached as high as a friction coefficient of 0.25, and their persistence depended on the hardness of the disc surface. On the basis of elastohydrodynamic theory, coupled with the observation of severe plastic deformation on the ridges parallel to the sliding direction, the frictional spike could be due to localized plastic deformation on the disc surface at locations of minimal thickness for the lubricant fluid film. This hypothesis was further supported by lack of frictional spikes in tests using discs coated with a thin film of diamond-like carbon, in which plastic deformation is minimal.

  10. Fluorescence photon migration by the boundary element method

    SciTech Connect (OSTI)

    Fedele, Francesco; Eppstein, Margaret J. . E-mail: maggie.eppstein@uvm.edu; Laible, Jeffrey P.; Godavarty, Anuradha; Sevick-Muraca, Eva M.

    2005-11-20

    The use of the boundary element method (BEM) is explored as an alternative to the finite element method (FEM) solution methodology for the elliptic equations used to model the generation and transport of fluorescent light in highly scattering media, without the need for an internal volume mesh. The method is appropriate for domains where it is reasonable to assume the fluorescent properties are regionally homogeneous, such as when using highly specific molecularly targeted fluorescent contrast agents in biological tissues. In comparison to analytical results on a homogeneous sphere, BEM predictions of complex emission fluence are shown to be more accurate and stable than those of the FEM. Emission fluence predictions made with the BEM using a 708-node mesh, with roughly double the inter-node spacing of boundary nodes as in a 6956-node FEM mesh, match experimental frequency-domain fluorescence emission measurements acquired on a 1087 cm{sup 3} breast-mimicking phantom at least as well as those of the FEM, but require only 1/8 to 1/2 the computation time.

  11. EXACT SOLUTION OF HEAT CONDUCTION IN A TWO-DOMAIN COMPOSITE CYLINDER WITH AN ORTHOTROPIC OUTER LAYER.

    SciTech Connect (OSTI)

    C. AVILES-RAMOS; C. RUDY

    2000-11-01

    The transient exact solution of heat conduction in a two-domain composite cylinder is developed using the separation of variables technique. The inner cylinder is isotropic and the outer cylindrical layer is orthotropic. Temperature solutions are obtained for boundary conditions of the first and second kinds at the outer surface of the orthotropic layer. These solutions are applied to heat flow calorimeters modeling assuming that there is heat generation due to nuclear reactions in the inner cylinder. Heat flow calorimeter simulations are carried out assuming that the inner cylinder is filled with plutonium oxide powder. The first objective in these simulations is to predict the onset of thermal equilibrium of the calorimeter with its environment. Two types of boundary conditions at the outer surface of the orthotropic layer are used to predict thermal equilibrium. The procedure developed to carry out these simulations can be used as a guideline for the design of calorimeters. Another important application of these solutions is on the estimation of thermophysical properties of orthotropic cylinders. The thermal conductivities in the vertical, radial and circumferential directions of the orthotropic outer layer can be estimated using this exact solution and experimental data. Simultaneous estimation of the volumetric heat capacity and thermal conductivities is also possible. Furthermore, this solution has potential applications to the solution of the inverse heat conduction problem in this cylindrical geometry. An interesting feature of the construction of this solution is that two different sets of eigenfunctions need to be considered in the eigenfunction expansion. These eigenfunctions sets depend on the relative values of the thermal diffusivity of the inner cylinder and the thermal diffusivity in the vertical direction of the outer cylindrical layer.

  12. Radiation May Indirectly Impair Growth Resulting in Reduced Standing Height via Subclinical Inflammation in Atomic-Bomb Survivors Exposed at Young Ages

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

    Nakashima, Eiji; Neriishi, Kazuo; Hsu, Wan-Ling

    2015-01-01

    For youngmore » atomic-bomb (A-bomb) survivors, A-bomb radiation’s (total) effect on standing height is thought to comprise the sum of direct effect and indirect effect via inflammation. With the data of five inflammatory markers—white blood cell count, sialic acid, corrected erythrocyte sedimentation rate (ESR), α 1 globulin, and α 2 globulin—obtained in adulthood during the period 1988 to 1992, a summary inflammatory index was constructed as a surrogate for the five subclinical inflammatory markers. For 3,327 A-bomb survivors exposed at ages of less than 25 years, a structural equation model was analyzed to measure direct radiation effects on adult height as well as mediating effect of radiation via inflammation on the height after adjustment for other risk factors, smoking, cancer, inflammatory disease, obesity, and diabetes mellitus. The mediation proportion of the radiation effect on height via inflammation was approximately 5% for both sexes for all ages, and indirect dose effects via inflammation were statistically significant for both sexes combined and for females exposed at ages 0 to 5 years. Indirect dose effects for all ages via sialic acid, corrected ESR, and α 2 globulin were marginally significant for both sexes combined and for females. These proportions are likely underestimated.« less

  13. Buffer layers on biaxially textured metal substrates

    DOE Patents [OSTI]

    Shoup, Shara S.; Paranthamam, Mariappan; Beach, David B.; Kroeger, Donald M.; Goyal, Amit

    2001-01-01

    A method is disclosed for forming a biaxially textured buffer layer on a biaxially oriented metal substrate by using a sol-gel coating technique followed by pyrolyzing/annealing in a reducing atmosphere. This method is advantageous for providing substrates for depositing electronically active materials thereon.

  14. Atomic layer deposition of nanoporous biomaterials.

    SciTech Connect (OSTI)

    Narayan, R. J.; Adiga, S. P.; Pellin, M. J.; Curtiss, L. A.; Stafslien, S.; Chisholm, B.; Monteiro-Riviere, N. A.; Brigmon, R. L.; Elam, J. W.; Univ. of North Carolina; North Carolina State Univ.; Eastman Kodak Co.; North Dakota State Univ.; SRL

    2010-03-01

    Due to its chemical stability, uniform pore size, and high pore density, nanoporous alumina is being investigated for use in biosensing, drug delivery, hemodialysis, and other medical applications. In recent work, we have examined the use of atomic layer deposition for coating the surfaces of nanoporous alumina membranes. Zinc oxide coatings were deposited on nanoporous alumina membranes using atomic layer deposition. The zinc oxide-coated nanoporous alumina membranes demonstrated antimicrobial activity against Escherichia coli and Staphylococcus aureus bacteria. These results suggest that atomic layer deposition is an attractive technique for modifying the surfaces of nanoporous alumina membranes and other nanostructured biomaterials. Nanoporous alumina, also known as anodic aluminum oxide (AAO), is a nanomaterial that exhibits several unusual properties, including high pore densities, straight pores, small pore sizes, and uniform pore sizes. In 1953, Keller et al. showed that anodizing aluminum in acid electrolytes results in a thick layer of nearly cylindrical pores, which are arranged in a close-packed hexagonal cell structure. More recently, Matsuda & Fukuda demonstrated preparation of highly ordered platinum and gold nanohole arrays using a replication process. In this study, a negative structure of nanoporous alumina was initially fabricated and a positive structure of a nanoporous metal was subsequently fabricated. Over the past fifteen years, nanoporous alumina membranes have been used as templates for growth of a variety of nanostructured materials, including nanotubes, nanowires, nanorods, and nanoporous membranes.

  15. Double layer capacitor prospects look good

    SciTech Connect (OSTI)

    1995-07-01

    The Fourth International Seminar in Double Layer Capacitors and similar energy devices has been sponsored again by Dr. S.P. Wolsky and Dr. Nikola Marincic. The seminar was held in December 1994, at Deerfield Beach, FL. This report provides a brief description of information on supercapacitors.

  16. Nano-soldering to single atomic layer

    DOE Patents [OSTI]

    Girit, Caglar O.; Zettl, Alexander K.

    2011-10-11

    A simple technique to solder submicron sized, ohmic contacts to nanostructures has been disclosed. The technique has several advantages over standard electron beam lithography methods, which are complex, costly, and can contaminate samples. To demonstrate the soldering technique graphene, a single atomic layer of carbon, has been contacted, and low- and high-field electronic transport properties have been measured.

  17. Quantum Security for the Physical Layer

    SciTech Connect (OSTI)

    Humble, Travis S

    2013-01-01

    The physical layer describes how communication signals are encoded and transmitted across a channel. Physical security often requires either restricting access to the channel or performing periodic manual inspections. In this tutorial, we describe how the field of quantum communication offers new techniques for securing the physical layer. We describe the use of quantum seals as a unique way to test the integrity and authenticity of a communication channel and to provide security for the physical layer. We present the theoretical and physical underpinnings of quantum seals including the quantum optical encoding used at the transmitter and the test for non-locality used at the receiver. We describe how the envisioned quantum physical sublayer senses tampering and how coordination with higher protocol layers allow quantum seals to influence secure routing or tailor data management methods. We conclude by discussing challenges in the development of quantum seals, the overlap with existing quantum key distribution cryptographic services, and the relevance of a quantum physical sublayer to the future of communication security.

  18. Layered method of electrode for solid oxide electrochemical cells

    SciTech Connect (OSTI)

    Jensen, R.R.

    1991-07-30

    This patent describes a fuel electrode. It comprises a first layer comprising substantially stabilized zirconia; a second layer, in intimate contact with the first layer, comprising a mixture of stabilized zirconia and metal powder selected from the group consisting of nickel, palladium, platinum and cobalt; and a third layer comprising substantially metal powder selected from the group consisting of nickel, palladium, platinum and cobalt.

  19. Pd/Ni-WO3 anodic double layer gasochromic device

    DOE Patents [OSTI]

    Lee, Se-Hee; Tracy, C. Edwin; Pitts, J. Roland; Liu, Ping

    2004-04-20

    An anodic double layer gasochromic sensor structure for optical detection of hydrogen in improved response time and with improved optical absorption real time constants, comprising: a glass substrate; a tungsten-doped nickel oxide layer coated on the glass substrate; and a palladium layer coated on the tungsten-doped nickel oxide layer.

  20. Double layer field shaping systems for toroidal plasmas

    DOE Patents [OSTI]

    Ohyabu, Nobuyoshi

    1982-01-01

    Methods and apparatus for plasma generation, confinement and control such as Tokamak plasma systems are described having a two layer field shaping coil system comprising an inner coil layer close to the plasma and an outer coil layer to minimize the current in the inner coil layer.

  1. Multiscale model of metal alloy oxidation at grain boundaries

    SciTech Connect (OSTI)

    Sushko, Maria L. Alexandrov, Vitaly; Schreiber, Daniel K.; Rosso, Kevin M.; Bruemmer, Stephen M.

    2015-06-07

    High temperature intergranular oxidation and corrosion of metal alloys is one of the primary causes of materials degradation in nuclear systems. In order to gain insights into grain boundary oxidation processes, a mesoscale metal alloy oxidation model is established by combining quantum Density Functional Theory (DFT) and mesoscopic Poisson-Nernst-Planck/classical DFT with predictions focused on Ni alloyed with either Cr or Al. Analysis of species and fluxes at steady-state conditions indicates that the oxidation process involves vacancy-mediated transport of Ni and the minor alloying element to the oxidation front and the formation of stable metal oxides. The simulations further demonstrate that the mechanism of oxidation for Ni-5Cr and Ni-4Al is qualitatively different. Intergranular oxidation of Ni-5Cr involves the selective oxidation of the minor element and not matrix Ni, due to slower diffusion of Ni relative to Cr in the alloy and due to the significantly smaller energy gain upon the formation of nickel oxide compared to that of Cr{sub 2}O{sub 3}. This essentially one-component oxidation process results in continuous oxide formation and a monotonic Cr vacancy distribution ahead of the oxidation front, peaking at alloy/oxide interface. In contrast, Ni and Al are both oxidized in Ni-4Al forming a mixed spinel NiAl{sub 2}O{sub 4}. Different diffusivities of Ni and Al give rise to a complex elemental distribution in the vicinity of the oxidation front. Slower diffusing Ni accumulates in the oxide and metal within 3 nm of the interface, while Al penetrates deeper into the oxide phase. Ni and Al are both depleted from the region 3–10 nm ahead of the oxidation front creating voids. The oxide microstructure is also different. Cr{sub 2}O{sub 3} has a plate-like structure with 1.2–1.7 nm wide pores running along the grain boundary, while NiAl{sub 2}O{sub 4} has 1.5 nm wide pores in the direction parallel to the grain boundary and 0.6 nm pores in the perpendicular

  2. Back contact buffer layer for thin-film solar cells

    DOE Patents [OSTI]

    Compaan, Alvin D.; Plotnikov, Victor V.

    2014-09-09

    A photovoltaic cell structure is disclosed that includes a buffer/passivation layer at a CdTe/Back contact interface. The buffer/passivation layer is formed from the same material that forms the n-type semiconductor active layer. In one embodiment, the buffer layer and the n-type semiconductor active layer are formed from cadmium sulfide (CdS). A method of forming a photovoltaic cell includes the step of forming the semiconductor active layers and the buffer/passivation layer within the same deposition chamber and using the same material source.

  3. Thin film solar cell including a spatially modulated intrinsic layer

    SciTech Connect (OSTI)

    Guha, Subhendu; Yang, Chi-Chung; Ovshinsky, Stanford R.

    1989-03-28

    One or more thin film solar cells in which the intrinsic layer of substantially amorphous semiconductor alloy material thereof includes at least a first band gap portion and a narrower band gap portion. The band gap of the intrinsic layer is spatially graded through a portion of the bulk thickness, said graded portion including a region removed from the intrinsic layer-dopant layer interfaces. The band gap of the intrinsic layer is always less than the band gap of the doped layers. The gradation of the intrinsic layer is effected such that the open circuit voltage and/or the fill factor of the one or plural solar cell structure is enhanced.

  4. Conductive layer for biaxially oriented semiconductor film growth

    DOE Patents [OSTI]

    Findikoglu, Alp T.; Matias, Vladimir

    2007-10-30

    A conductive layer for biaxially oriented semiconductor film growth and a thin film semiconductor structure such as, for example, a photodetector, a photovoltaic cell, or a light emitting diode (LED) that includes a crystallographically oriented semiconducting film disposed on the conductive layer. The thin film semiconductor structure includes: a substrate; a first electrode deposited on the substrate; and a semiconducting layer epitaxially deposited on the first electrode. The first electrode includes a template layer deposited on the substrate and a buffer layer epitaxially deposited on the template layer. The template layer includes a first metal nitride that is electrically conductive and has a rock salt crystal structure, and the buffer layer includes a second metal nitride that is electrically conductive. The semiconducting layer is epitaxially deposited on the buffer layer. A method of making such a thin film semiconductor structure is also described.

  5. The boundary effects of the shock wave dispersion in discharges

    SciTech Connect (OSTI)

    Markhotok, A.; Popovic, S.; Vuskovic, L.

    2008-03-15

    Interaction of shock waves with a weakly ionized gas generated by discharges has been studied. An additional thermal mechanism of the shock wave dispersion on the boundary between a neutral gas and discharge has been proposed [A. Markhotok, S. Popovic, and L. Vuskovic, Proceedings of the 15th International Conference on Atomic Processes in Plasmas, March 19-22, 2007 (NIST, Gaitersburg, MD, 2007)]. This mechanism can explain a whole set of thermal features of the shock wave-plasma interaction, including acceleration of the shock wave, broadening or splitting of the deflection signals and its consecutive restoration. Application has been made in the case of a shock wave interacting with a laser induced plasma. The experimental observations support well the results of calculation based on this model.

  6. THE HELIOTAIL REVEALED BY THE INTERSTELLAR BOUNDARY EXPLORER

    SciTech Connect (OSTI)

    McComas, D. J.; Dayeh, M. A.; Livadiotis, G.; Funsten, H. O.; Schwadron, N. A.

    2013-07-10

    Recent combined observations from the first three years of Interstellar Boundary Explorer (IBEX) data allow us to examine the heliosphere's downwind region-the heliotail-for the first time. In contrast to a preliminary identification of a narrow ''offset heliotail'' structure, we find a broad slow solar wind plasma sheet crossing essentially the entire downwind side of the heliosphere at low to mid-latitudes, with fast wind tail regions to the north and south. The slow wind plasma sheet exhibits the steepest ENA spectra in the IBEX sky maps, appears as a two-lobed structure (lobes on the port and starboard sides), and is twisted in the sense of (but at a smaller angle than) the external magnetic field. The overall heliotail structure clearly demonstrates the intermediate nature of the heliosphere's interstellar interaction, where both the external dynamic and magnetic pressures strongly affect the heliosphere.

  7. AB INITIO STUDY OF GRAIN BOUNDARY PROPERTIES OF TUNGSTEN ALLOYS

    SciTech Connect (OSTI)

    Setyawan, Wahyu; Kurtz, Richard J.

    2012-04-17

    Density functional theory was employed to investigate the grain boundary (GB) property of W-TM alloys (TM: fifth and sixth row transition metals). GB strengthening was found for Hf, Ta, Nb, Ru, Re, Os and Ir for 27{l_brace}525{r_brace} and to a lesser degree for 11{l_brace}323{r_brace}. Lower valence solutes strengthen the GB at certain substitutional sites, while higher valence elements enforce it at other positions. For 3{l_brace}112{r_brace}, the alloys exhibit reduced cleavage energies. Hence, allowing with TMs increases the GB cohesion more effectively for large-angle GBs whose cleavage energy is, in general, inherently lower than the low-angle ones. Electron density analysis elucidates the mechanism of charge addition or depletion of the GB bonding region upon TM substitution at various positions leading to stronger or weaker intergranular cohesion, respectively.

  8. SDO OBSERVATIONS OF MAGNETIC RECONNECTION AT CORONAL HOLE BOUNDARIES

    SciTech Connect (OSTI)

    Yang Shuhong; Zhang Jun; Li Ting; Liu Yang E-mail: zjun@nao.cas.cn E-mail: yliu@quake.stanford.edu

    2011-05-01

    With the observations from the Atmospheric Imaging Assembly and the Helioseismic and Magnetic Imager on board the Solar Dynamics Observatory, we investigate the coronal hole boundaries (CHBs) of an equatorial extension of the polar coronal hole. At the CHBs, many extreme-ultraviolet jets, which appear to be the signatures of magnetic reconnection, are observed in the 193 A images, and some jets occur repetitively at the same sites. The evolution of the jets is associated with the emergence and cancellation of magnetic fields. We note that both the east and west CHBs shift westward, and the shift velocities are close to the velocities of rigid rotation compared with those of the photospheric differential rotation. This indicates that magnetic reconnection at CHBs results in the evolution of CHBs and maintains the rigid rotation of coronal holes.

  9. The growth mechanism of grain boundary carbide in Alloy 690

    SciTech Connect (OSTI)

    Li, Hui; Xia, Shuang; Zhou, Bangxin; Peng, Jianchao

    2013-07-15

    The growth mechanism of grain boundary M{sub 23}C{sub 6} carbides in nickel base Alloy 690 after aging at 715 °C was investigated by high resolution transmission electron microscopy. The grain boundary carbides have coherent orientation relationship with only one side of the matrix. The incoherent phase interface between M{sub 23}C{sub 6} and matrix was curved, and did not lie on any specific crystal plane. The M{sub 23}C{sub 6} carbide transforms from the matrix phase directly at the incoherent interface. The flat coherent phase interface generally lies on low index crystal planes, such as (011) and (111) planes. The M{sub 23}C{sub 6} carbide transforms from a transition phase found at curved coherent phase interface. The transition phase has a complex hexagonal crystal structure, and has coherent orientation relationship with matrix and M{sub 23}C{sub 6}: (111){sub matrix}//(0001){sub transition}//(111){sub carbide}, <112{sup ¯}>{sub matrix}//<21{sup ¯}10>{sub transition}//<112{sup ¯}>{sub carbide}. The crystal lattice constants of transition phase are c{sub transition}=√(3)×a{sub matrix} and a{sub transition}=√(6)/2×a{sub matrix}. Based on the experimental results, the growth mechanism of M{sub 23}C{sub 6} and the formation mechanism of transition phase are discussed. - Highlights: • A transition phase was observed at the coherent interfaces of M{sub 23}C{sub 6} and matrix. • The transition phase has hexagonal structure, and is coherent with matrix and M{sub 23}C{sub 6}. • The M{sub 23}C{sub 6} transforms from the matrix directly at the incoherent phase interface.

  10. Transition in electron scattering mechanism in atomic layer deposited Nb:TiO{sub 2} thin films

    SciTech Connect (OSTI)

    Niemel, Janne-Petteri; Karppinen, Maarit; Hirose, Yasushi; Hasegawa, Tetsuya

    2015-01-26

    We characterized transport and optical properties of atomic layer deposited Nb:TiO{sub 2} thin films on glass substrates. These promising transparent conducting oxide (TCO) materials show minimum resistivity of 1.0??10{sup ?3?}??cm at 300?K and high transmittance in the visible range. Low-temperature (2300?K) Hall measurements and the Drude fitting of the Vis-NIR optical spectra indicate a transition in the scattering mechanism from grain boundary scattering to intra-grain scattering with increasing Nb content, thus underlining enhancement of the grain size in the low doping regime as the key for further improved TCO properties.

  11. Faceting of {sigma}3 and {sigma}9 grain boundaries in Cu-Bi alloys

    SciTech Connect (OSTI)

    Straumal, B.B. . E-mail: straumal@issp.ac.ru; Polyakov, S.A.; Bischoff, E.; Gust, W.; Baretzky, B.

    2005-01-10

    The faceting of {sigma}3 and {sigma}9 tilt grain boundaries (GBs) has been studied in bicrystals of pure Cu and Cu-Bi alloys containing 2.5 x 10{sup -3}, 10 x 10{sup -3} and 16 x 10{sup -3} at.% Bi. The {sigma}3(1 0 0), {sigma}9(1 0 0), {sigma}9(-1 1 0), and {sigma}9(-1 2 0) facets and non-CSL {sigma}3 82 deg 9R facet were observed, where {sigma} is the inverse density of coincidence sites. The ratio between GB energy, {sigma}{sub GB}, and surface energy, {sigma}{sub sur}, was measured by atomic force microscopy using the GB thermal-groove method. The GB energy and thermal-groove deepening rate increased slightly between 0 and 10 x 10{sup -3} at.% Bi for all facets studied. However, between 10 x 10{sup -3} and 16 x 10{sup -3} at.% Bi the GB energy increased dramatically [from a factor 2 for the {sigma}9(1 1 0) facet to 15 times larger for the {sigma}3(1 0 0) facet]. The thermal-groove deepening rate also increased by a factor of 10 in this concentration range. This change corresponds well with the GB solidus line (i.e., the formation of a stable layer of a liquid-like GB phase called GB prewetting) observed previously. Wulff diagrams were constructed using measured {sigma}{sub GB}/{sigma}{sub sur} values.

  12. Prospects for Simulating Macromolecular Surfactant Chemistry at the Ocean-Atmosphere Boundary

    SciTech Connect (OSTI)

    Elliott, S.; Burrows, Susannah M.; Deal, C.; Liu, Xiaohong; Long, M.; Ogunro, O.; Russell, Lynn M.; Wingenter, O.

    2014-05-01

    Biogenic lipids and polymers are surveyed for their ability to adsorb at the water-air interfaces associated with bubbles, marine microlayers and particles in the overlying boundary layer. Representative ocean biogeochemical regimes are defined in order to estimate local concentrations for the major macromolecular classes. Surfactant equilibria and maximum excess are then derived based on a network of model compounds. Relative local coverage and upward mass transport follow directly, and specific chemical structures can be placed into regional rank order. Lipids and denatured protein-like polymers dominate at the selected locations. The assigned monolayer phase states are variable, whether assessed along bubbles or at the atmospheric spray droplet perimeter. Since oceanic film compositions prove to be irregular, effects on gas and organic transfer are expected to exhibit geographic dependence as well. Moreover, the core arguments extend across the sea-air interface into aerosol-cloud systems. Fundamental nascent chemical properties including mass to carbon ratio and density depend strongly on the geochemical state of source waters. High surface pressures may suppress the Kelvin effect, and marine organic hygroscopicities are almost entirely unconstrained. While bubble adsorption provides a well-known means for transporting lipidic or proteinaceous material into sea spray, the same cannot be said of polysaccharides. Carbohydrates tend to be strongly hydrophilic so that their excess carbon mass is low despite stacked polymeric geometries. Since sugars are abundant in the marine aerosol, gel-based mechanisms may be required to achieve uplift. Uncertainties in the surfactant logic distill to a global scale dearth of information regarding two dimensional kinetics and equilibria. Nonetheless simulations are recommended, to initiate the process of systems level quantification.

  13. Elastodynamic behavior of the three dimensional layer-by-layer metamaterial structure

    SciTech Connect (OSTI)

    Aravantinos-Zafiris, N.; Sigalas, M. M.; Economou, E. N.

    2014-10-07

    In this work, we numerically investigate for the first time the elastodynamic behavior of a three dimensional layer-by-layer rod structure, which is easy to fabricate and has already proved to be very efficient as a photonic crystal. The Finite Difference Time Domain method was used for the numerical calculations. For the rods, several materials were examined and the effects of all the geometric parameters of the structure were also numerically investigated. Additionally, two modifications of the structure were included in our calculations. The results obtained here (for certain geometric parameters), exhibiting a high ratio of longitudinal over transverse sound velocity and therefore a close approach to ideal pentamode behavior over a frequency range, clearly show that the layer-by-layer rod structure, besides being an efficient photonic crystal, is a very serious contender as an elastodynamic metamaterial.

  14. Method of adhesion between an oxide layer and a metal layer

    DOE Patents [OSTI]

    Jennison, Dwight R.; Bogicevic, Alexander; Kelber, Jeffry A.; Chambers, Scott A.

    2004-09-14

    A method of controlling the wetting characteristics and increasing the adhesion between a metal and an oxide layer. By introducing a negatively-charged species to the surface of an oxide layer, layer-by-layer growth of metal deposited onto the oxide surface is promoted, increasing the adhesion strength of the metal-oxide interface. The negatively-charged species can either be deposited onto the oxide surface or a compound can be deposited that dissociates on, or reacts with, the surface to form the negatively-charged species. The deposited metal adatoms can thereby bond laterally to the negatively-charged species as well as vertically to the oxide surface as well as react with the negatively charged species, be oxidized, and incorporated on or into the surface of the oxide.

  15. Consideration of Grain Size Distribution in the Diffusion of Fission Gas to Grain Boundaries

    SciTech Connect (OSTI)

    Paul C. Millett; Yongfeng Zhang; Michael R. Tonks; S. B. Biner

    2013-09-01

    We analyze the accumulation of fission gas on grain boundaries in a polycrystalline microstructure with a distribution of grain sizes. The diffusion equation is solved throughout the microstructure to evolve the gas concentration in space and time. Grain boundaries are treated as infinite sinks for the gas concentration, and we monitor the cumulative gas inventory on each grain boundary throughout time. We consider two important cases: first, a uniform initial distribution of gas concentration without gas production (correlating with post-irradiation annealing), and second, a constant gas production rate with no initial gas concentration (correlating with in-reactor conditions). The results show that a single-grain-size model, such as the Booth model, over predicts the gas accumulation on grain boundaries compared with a polycrystal with a grain size distribution. Also, a considerable degree of scatter, or variability, exists in the grain boundary gas accumulation when comparing all of the grain boundaries in the microstructure.

  16. Computer simulation study of the structure of vacancies in grain boundaries

    SciTech Connect (OSTI)

    Brokman, A.; Bristowe, P.D.; Balluffi, R.W.

    1981-01-01

    The structure of vacancies in grain boundaries has been investigated by computer molecular statics employing pairwise potentials. In order to gain an impression of the vacancy structures which may occur generally, a number of variables was investigated including: metal type, boundary type, degree of lattice coincidence and choice of boundary site. In all cases the vacancies remained as distinguishable point defects in the relatively irregular boundary structures. However, it was found that the vacancy often induced relatively large atomic displacements in the core of the boundary. These displacements often occurred only in the direct vicinity of the vacancy, but in certain cases they were widely distributed in the boundary, sometimes at surprisingly large distances.

  17. ARM: ARSCL: cloud boundaries from first Clothiaux algorithms on Vaisala or Belfort ceilometers, Micropulse lidar, and MMCR

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

    Karen Johnson; Michael Jensen

    ARSCL: cloud boundaries from first Clothiaux algorithms on Vaisala or Belfort ceilometers, Micropulse lidar, and MMCR

  18. ARM: ARSCL: cloud boundaries from first Clothiaux algorithms on Vaisala or Belfort ceilometers, Micropulse lidar, and MMCR

    SciTech Connect (OSTI)

    Karen Johnson; Michael Jensen

    1996-11-08

    ARSCL: cloud boundaries from first Clothiaux algorithms on Vaisala or Belfort ceilometers, Micropulse lidar, and MMCR

  19. Revisit boundary conditions for the self-adjoint angular flux formulation

    SciTech Connect (OSTI)

    Wang, Yaqi; Gleicher, Frederick N.

    2015-03-01

    We revisit the boundary conditions for SAAF. We derived the equivalent parity variational form ready for coding up. The more rigorous approach of evaluating odd parity should be solving the odd parity equation coupled with the even parity. We proposed a symmetric reflecting boundary condition although neither positive definiteness nor even-odd decoupling is achieved. A simple numerical test verifies the validity of these boundary conditions.

  20. Interface engineering in epitaxial growth of layered oxides via a conducting layer insertion

    SciTech Connect (OSTI)

    Yun, Yu; Meng, Dechao; Wang, Jianlin; Ma, Chao; Zhai, Xiaofang; Huang, Haoliang; Fu, Zhengping; Peng, Ranran; Brown, Gail J.; and others

    2015-07-06

    There is a long-standing challenge in the fabrication of layered oxide epitaxial films due to their thermodynamic phase-instability and the large stacking layer number. Recently, the demand for high-quality thin films is strongly pushed by their promising room-temperature multiferroic properties. Here, we find that by inserting a conducting and lattice matched LaNiO{sub 3} buffer layer, high quality m = 5 Bi{sub 6}FeCoTi{sub 3}O{sub 18} epitaxial films can be fabricated using the laser molecular beam epitaxy, in which the atomic-scale sharp interface between the film and the metallic buffer layer explains the enhanced quality. The magnetic and ferroelectric properties of the high quality Bi{sub 6}FeCoTi{sub 3}O{sub 18} films are studied. This study demonstrates that insertion of the conducting layer is a powerful method in achieving high quality layered oxide thin films, which opens the door to further understand the underline physics and to develop new devices.