Sample records for activity population density

  1. Population Density Population density (persons per square kilometer) layers, for 1990

    E-Print Network [OSTI]

    Columbia University

    Population Density Africa Population density (persons per square kilometer) layers, for 1990 the 12 population density classes. Source information: http://sedac.ciesin.columbia.edu/gpw/. ´ Robinson://sedac.ciesin.columbia.edu/place/ Publish Date: 03/13/07 0 1,000 km Population Density 2000 0 Persons \\ Sq.Km 0-2 Persons \\ Sq.Km 2

  2. relatively high population density (much of it living inland) and small

    E-Print Network [OSTI]

    Darton, Richard

    relatively high population density (much of it living inland) and small rivers this is an important of filters such as activated carbon. The main problem is one of scale. A city such as Northampton, UK energy intensive drinking water purification technology in such a case would be an expensive undertaking

  3. Estimating low-density snowshoe hare populations using fecal pellet counts

    E-Print Network [OSTI]

    Estimating low-density snowshoe hare populations using fecal pellet counts Dennis L. Murray, James americanus) populations found at high densities can be estimated using fecal pellet densities on rectangular of fecal pellet plots for estimating hare populations by correlating pellet densities with estimated hare

  4. Density Functional Theory Study of Oxygen Reduction Activity...

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

    Study of Oxygen Reduction Activity on Ultrathin Platinum Nanotubes. Density Functional Theory Study of Oxygen Reduction Activity on Ultrathin Platinum Nanotubes. Abstract: The...

  5. Influence of landscape elements on population densities and habitat use of three small-mammal species.

    SciTech Connect (OSTI)

    Mabry, Karen, E.; Dreelin, Erin, A.; Barrett, Gary, W.

    2003-01-01T23:59:59.000Z

    Mabry, K.E., E.A. Dreelin, and G.W. Barrett. 2003. Influence of landscape elements on population densities and habitat use of three small-mammal species. J. Mammology. 84(1):20-25. Corridor effects on population densities and habitat use of 3 small mammal species were assessed in an experimentally fragmented landscape. Corridor presence did not have a statistically significant effect on population densities of cotton rats or cotton mice; however, a significant effect was observed for old-field mice. The results suggest that landscape fragmentation and habitat structure may have varying effects on population densities of different species.

  6. active microbial populations: Topics by E-print Network

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

    of enzyme activity Paris-Sud XI, Universit de 2 MICROBIAL POPULATIONS FECAL PELLETS AND Geosciences Websites Summary: MICROBIAL POPULATIONS FECAL PELLETS AND AND...

  7. Unbiased estimators of wildlife population densities using aural information

    E-Print Network [OSTI]

    Durland, Eric Newton

    1969-01-01T23:59:59.000Z

    . Using L' = 1. 99, and p = 1/3, from (30) an estimate of the density is n 108. 85 f A ] 99(3)(4QQQ)(] /3) . 0136 dove pairs/acre s = 1. 36 dove pairs/100 acres. 25 This is the same estimate we obtained using DI. The reason for this is explained...(7. 50) 1. 12 ? (2 422) (3) (40) (1(3) (0. 96, l. 28) 3. 4 Suggestions for Improvements At present, the call-count technique for estimating the density of mourning doves seems satisfactory for establishing a relative density index, but to get a good...

  8. Population Ecology at the Range Edge Survival and Dispersal of a High-Density Lepidopteran

    E-Print Network [OSTI]

    Population Ecology at the Range Edge Survival and Dispersal of a High-Density Lepidopteran Population Cecilia Ronnås Faculty of Natural Resources and Agricultural Sciences Department of Ecology Service/Repro, Uppsala 2011 #12;Population Ecology at the Range Edge. Survival and Dispersal of a High

  9. Effects of Landscape Manipulation on Population Densities, Habitat Utilization, Home Ranges, and Movements of Three Small Mammal Species

    SciTech Connect (OSTI)

    Mabry, K.E.

    2001-07-01T23:59:59.000Z

    No significant differences were found in the population densities of any species in experimentally fragmented landscape. However, trends in population densities indicate that connected patches usually support higher densities of cotton rats, isolated patches supported higher densities of old-field mice. No significant trends in population densities were observed for cotton mice. Cotton mice were captured more often in corridors, while old-field mice were captured more frequently in the interior. Results suggest landscape fragmentation has less of an effect on cotton mice-a habitat generalist.

  10. Estimating electric current densities in solar active regions

    E-Print Network [OSTI]

    Wheatland, M S

    2015-01-01T23:59:59.000Z

    Electric currents in solar active regions are thought to provide the energy released via magnetic reconnection in solar flares. Vertical electric current densities $J_z$ at the photosphere may be estimated from vector magnetogram data, subject to substantial uncertainties. The values provide boundary conditions for nonlinear force- free modelling of active region magnetic fields. A method is presented for estimating values of $J_z$ taking into account uncertainties in vector magnetogram field values, and minimizing $J_z^2$ across the active region. The method is demonstrated using the boundary values of the field for a force-free twisted bipole, with the addition of noise at randomly chosen locations.

  11. Pattern Formation in Populations with Density-Dependent Movement and Two Interaction Scales

    E-Print Network [OSTI]

    Martnez-Garca, Ricardo; Hernndez-Garca, Emilio; Lpez, Cristbal

    2015-01-01T23:59:59.000Z

    We study the spatial patterns formed by a system of interacting particles where the mobility of any individual is determined by the population crowding at two different spatial scales. In this way we model the behavior of some biological organisms (like mussels) that tend to cluster at short ranges as a defensive strategy, and strongly disperse if there is a high population pressure at large ranges for optimizing foraging. We perform stochastic simulations of a particle-level model of the system, and derive and analyze a continuous density description (a nonlinear diffusion equation). In both cases we show that this interplay of scale-dependent-behaviors gives rise to a rich formation of spatial patterns ranging from labyrinths to periodic cluster arrangements. In most cases these clusters have the very peculiar appearance of ring-like structures, i.e., organisms arranging in the perimeter of the clusters, that we discuss in detail.

  12. Effects of population density on estrous cycles of two-year old quarter horse mares

    E-Print Network [OSTI]

    Burke, Daniel John

    1978-01-01T23:59:59.000Z

    0. 8 O u) 06 IZ I- UJ o 04 D' C( D M O D- ? O CONTROL PEN UJ X 0. 0 2/21- 3/13- 4/2- 4/22- 5/1 2-, 6/2- 3/1 2 4/1 4/21 5/1 1 6/1 6/20 TIME PERIOD COMPRISED OF COMPARABLE CYCLES Figure 4. Seasonal effects of heat intensity. 30...EFFECTS OF POPULATION DENSITY ON ESTROUS CYCLES OF TWO-YEAR OLD QUARTER HORSE MARES A Thesis by DANIEL JOHN BURKE Submitted to the Graduate College of Texas ASM University in partial fulfillment of the requirement for the degree of MASTER...

  13. Central stellar populations of early-type galaxies in low-density environments

    E-Print Network [OSTI]

    M. Collobert; M. Sarzi; R. L. Davies; H. Kuntschner; Matthew Colless

    2006-05-24T23:59:59.000Z

    We have investigated the properties of a volume and magnitude limited sample of nearby early type galaxies that were carefully selected from the AAO two degree field galaxy redshift survey. We used images from the DSS to confirm the E/S0 morphologies, and augmented this sample with field galaxies from Colbert et al. 2001. We present spectroscopic observations of 22 galaxies from the combined sample, from which central velocity dispersions and the Lick stellar population indices were measured. After carefully correcting the spectra for nebular emission we derived luminosity-weighted ages, metallicities, and alpha-element abundance ratios. We compare these isolated galaxies with samples of early-type galaxies in the Virgo and Coma clusters, and also with the sample of galaxies in low-density regions of Kuntschner et al. (2002). We find that galaxies in low-density environments are younger and have a greater spread of ages compared to cluster galaxies. They also show a wider range of metallicities at a given velocity dispersion than cluster galaxies, which display only super-solar metallicities. On average cluster, as well as, isolated galaxies show non-solar abundance ratios in alpha-elements, suggesting that, independent of galactic environment, star formation occurred on short time-scales. We reason that early-type galaxies in low-density environments experienced merging-induced star-formation episodes over a longer and more recent period of time compared to a cluster environment, and speculate that a considerable fraction of their stars formed out of low-metallicity halo gaseous material during the slow growth of a stellar disk between merging events.

  14. Genetic variation of packing density within a selected population of Loblolly Pine (Pinus taeda L.

    E-Print Network [OSTI]

    Boyd, Lamar

    1967-01-01T23:59:59.000Z

    . Specific gravity of cell wall material Factors affecting the specific gravity of cell wall material Importance of the specific gravity of cell wall material Recent investigations concerning packing density 12 Chapter IV. Experimental des ign 13... Discussion of materials 13 Sample size 14 Chapter V. Method used for determining packing density in small wood samples 15 Definition and calculation 15 Measurement of specific gravity Measurement of cell wall material 15 17 Summary of overall...

  15. Density structure of an active region and associated moss using Hinode/EIS

    E-Print Network [OSTI]

    D. Tripathi; H. E. Mason; P. R. Young; G. Del Zanna

    2008-02-22T23:59:59.000Z

    Context: Studying the problem of active region heating requires precise measurements of physical plasma parameters such as electron density, temperature etc. It is also important to understand the relationship of coronal structures with the magnetic field. The Extreme-ultraviolet Imaging Spectrometer (EIS) aboard Hinode provides a rare opportunity to derive electron density simultaneously at different temperatures. Aims: MethodsWe study the density structure and characterise plasma in active regions and associated moss regions. In addition we study its relationship to the photospheric magnetic field. Methods: We used data recorded by the EIS, together with magnetic field measurements from the Michelson Doppler Imager (MDI) aboard SoHO and images recorded with the Transition Region And Coronal Explorer (TRACE) and X-Ray Telescope (XRT/Hinode). Results: We find that the hot core of the active region is densest with values as high as 10^10.5 cm^-3. The electron density estimated in specific regions in the active region moss decreases with increasing temperature. The moss areas were located primarily on one side of the active region, and they map the positive polarity regions almost exactly. The density within the moss region was highest at log T=5.8-6.1, with a value around 10^(10.0-10.5) cm^-3. The moss densities were highest in the strong positive magnetic field region. However, there was no such correlation for the negative polarity areas, where there was a large sunspot.

  16. Biomarker monitoring of a population residing near uranium mining activities

    SciTech Connect (OSTI)

    Au, W.W.; Legator, M.S.; Whorton, E.B.; Wilkinson, G.S.; Gabehart, G.J.; Lane, R.G. [Univ. of Texas Medical Branch, Galveston, TX (United States)

    1995-05-01T23:59:59.000Z

    We investigated whether residents residing near uranium mining operations (target population), who are potentially exposed to toxicants from mining waste, have increased genotoxic effects compared with people residing elsewhere (reference population). Population surveys were conducted, and 24 target and 24 reference residents were selected. The selected subjects and controls were matched on age and gender and they were nonsmokers. Blood samples were collected for laboratory studies. The standard cytogenetic assay was used to determine chromosome aberration frequencies, and the challenge assay was used to investigate DNA repair responses. We found that individuals who resided near uranium mining operations had a higher mean frequency of cells with chromosome aberrations and higher deletion frequency but lower dicentric frequency than the reference group, although the difference was not statistically significant. After cells were challenged by exposure to {gamma}-rays, the target population had a significantly higher frequency of cells with chromosome aberrations and deletion frequency than the reference group. The latter observation is indicative of abnormal DNA repair response in the target population. 22 refs., 3 tabs.

  17. Topological Structure of Population Activity in Primary Visual Gurjeet Singh, Facundo Memoli, Tigran Ishkhanov,

    E-Print Network [OSTI]

    Stanford University

    sensitive dyes (Grinvald and Hildesheim, 2004), appears to switch dynamically among states, some of them to study the topological structure of neural activity in cell populations of primary visual cortex

  18. Density Functional Calculations of ATP Systems. 2. ATP Hydrolysis at the Active Site of J. Akola and R. O. Jones*

    E-Print Network [OSTI]

    Density Functional Calculations of ATP Systems. 2. ATP Hydrolysis at the Active Site of Actin J-triphosphate (ATP) at the active site of actin has been studied using density functional calculations. The active site is modeled by the triphosphate tail of ATP, an Mg cation, surrounding water molecules

  19. Sociological adaptation among bacterial populations in an activated sludge ecosystem

    E-Print Network [OSTI]

    Forrest, Robert George

    1970-01-01T23:59:59.000Z

    , Nm. B. Davis The predominant heterotrophic bacteria in a butanal adapted, laboratory scale, and batch fed activated sludge culture were mon- itored during substrate removal (as revealed by gas liouid chrom- atography), The changing concentrations...-Brevibacterium coryneforms (804) and Arthrobacter-like organisms (11$). Gram negative bacilli were rarely isolated, and the few observed were members of the genus Pseudomonas. The test culture (500 mg/1 oven dried solids) consistently re- moved up to 600 mg/1 of butanal...

  20. Heavy-duty truck population, activity and usage patterns. Final report

    SciTech Connect (OSTI)

    Fischer, M.

    1998-07-01T23:59:59.000Z

    The objective of the study was to update the heavy-duty truck (HDT) population, activity (e.g., vehicle miles traveled (VMT), numbers of starts and trips, trip duration, etc.), and usage patterns type of service/business (e.g., delivery, construction, etc.), area of operation (i.e., local, short-haul, long-haul) for HDT`s registered and/or operated in California. The population and activity estimates were done on a weight-class-specific basis light-heavy-duty, medium-heavy-duty and heavy-heavy-duty. Population, activity and usage estimates were based primarily on Department of Motor Vehicles (DMV) registration data and Truck Inventory and Usage Survey (TIUS) data. In addition to the analysis of existing data (i.e., DMV and TIUS), 42 HDTs were fitted with on-board data loggers that recorded numbers of trips and starts, daily VMT and travel by time-of-day.

  1. A density functional theory model of mechanically activated silyl ester hydrolysis

    SciTech Connect (OSTI)

    Pill, Michael F.; Schmidt, Sebastian W. [Department of Applied Sciences and Mechatronics, Munich University of Applied Sciences, Lothstr. 34, 80335 Munich (Germany) [Department of Applied Sciences and Mechatronics, Munich University of Applied Sciences, Lothstr. 34, 80335 Munich (Germany); Institut fr Physikalische Chemie, Christian-Albrechts-Universitt zu Kiel, Olshausenstrae 40, 24098 Kiel (Germany); Center for Nanoscience (CeNS), Geschwister-Scholl-Platz 1, 80539 Munich (Germany); Beyer, Martin K. [Institut fr Physikalische Chemie, Christian-Albrechts-Universitt zu Kiel, Olshausenstrae 40, 24098 Kiel (Germany) [Institut fr Physikalische Chemie, Christian-Albrechts-Universitt zu Kiel, Olshausenstrae 40, 24098 Kiel (Germany); Institut fr Ionenphysik und Angewandte Physik, Leopold-Franzens-Universitt Innsbruck, Technikerstrae 25, 6020 Innsbruck (Austria); Clausen-Schaumann, Hauke [Department of Applied Sciences and Mechatronics, Munich University of Applied Sciences, Lothstr. 34, 80335 Munich (Germany) [Department of Applied Sciences and Mechatronics, Munich University of Applied Sciences, Lothstr. 34, 80335 Munich (Germany); Center for Nanoscience (CeNS), Geschwister-Scholl-Platz 1, 80539 Munich (Germany); Kersch, Alfred, E-mail: akersch@hm.edu [Department of Applied Sciences and Mechatronics, Munich University of Applied Sciences, Lothstr. 34, 80335 Munich (Germany)] [Department of Applied Sciences and Mechatronics, Munich University of Applied Sciences, Lothstr. 34, 80335 Munich (Germany)

    2014-01-28T23:59:59.000Z

    To elucidate the mechanism of the mechanically activated dissociation of chemical bonds between carboxymethylated amylose (CMA) and silane functionalized silicon dioxide, we have investigated the dissociation kinetics of the bonds connecting CMA to silicon oxide surfaces with density functional calculations including the effects of force, solvent polarizability, and pH. We have determined the activation energies, the pre-exponential factors, and the reaction rate constants of candidate reactions. The weakest bond was found to be the silyl ester bond between the silicon and the alkoxy oxygen atom. Under acidic conditions, spontaneous proton addition occurs close to the silyl ester such that neutral reactions become insignificant. Upon proton addition at the most favored position, the activation energy for bond hydrolysis becomes 31 kJ?mol{sup ?1}, which agrees very well with experimental observation. Heterolytic bond scission in the protonated molecule has a much higher activation energy. The experimentally observed bi-exponential rupture kinetics can be explained by different side groups attached to the silicon atom of the silyl ester. The fact that different side groups lead to different dissociation kinetics provides an opportunity to deliberately modify and tune the kinetic parameters of mechanically activated bond dissociation of silyl esters.

  2. High-capacity electric double-layer capacitor with high-density-activated carbon fiber electrodes

    SciTech Connect (OSTI)

    Nakagawa, Hiroyuki; Shudo, Atsushi; Miura, Kouichi

    2000-01-01T23:59:59.000Z

    Recently the authors have presented a method to prepare activated carbon fiber with high bulk density (HD-ACF) without using any binders. The possibility of using the HD-ACF as an electrode for electric double-layer capacitors (EDLCs) was examined in this paper. The capacitance of the EDLC with the HD-ACF electrode increased with the increase of bulk density of the HD-ACF, indicating that individual fibers are highly packed without losing their capacitance. The capacitance also increased in proportion to the size of the HD-ACF electrode. The initial discharge current of the EDLC showed little dependency on either the bulk density or the size of the HD-ACF electrode. These results clarified that the HD-ACF electrode is suitable for constructing a high-power EDLC. The initial discharge current was directly proportional to the conductivity of aqueous KCI used as the electrolyte, indicating that the resistance of the electrolyte is much higher than that of the HD-ACF electrode. This result showed that the efficiency of the HD-ACF was well above the efficiency of the electrolyte used in this study and that the improvement of the ionic conductivity of electrolyte is also necessary for developing a high-power EDLC.

  3. Avian population densities and species diversity on reclaimed strip-mined land in East-Central Texas

    E-Print Network [OSTI]

    Cantle, Peter Christopher

    1978-01-01T23:59:59.000Z

    significant (P = 0. 05) pa1r wise contrasts for spec1es varying by "TRANSECT" in ANOUA; "+" or "-" indicates contrast constituent with greater density . Statist1cally s1onif1cant (P = 0. 05) pair-wise contrasts for species varying by "SEASON" in ANOUA... and drainages; dashed lines show boundaries between reclaim years; shaded areas represent remnant oak woodland; CVHR is coal vehicle haul road. Numbers ('72-'76) depict year of reclama- tion . 10 12 12 15 18 Picture of the 1974 Gradient transect area...

  4. Pore Size Analysis of Activated Carbons from Argon and Nitrogen Porosimetry Using Density Functional Theory

    E-Print Network [OSTI]

    Lastoskie, Christian M.

    Form: December 28, 1999 We present isotherms calculated from density functional theory. A similar set of density functional theory isotherms, previously reported for nitrogen adsorption on carbon Functional Theory Robert J. Dombrowski, Daniel R. Hyduke, and Christian M. Lastoskie* Department of Chemical

  5. ACTIVE CONTROL STRATEGY FOR DENSITY-WAVE IN GAS-LIFTED WELLS

    E-Print Network [OSTI]

    Saint-Pierre Pierre Lem´etayer CAS, ´Ecole des Mines de Paris, France CSTJF, TOTAL Exploration-Production: Process Control, Gas-Lifted Well, Density-wave, Stabilization. 1. INTRODUCTION Producing oil from deep) and the production pipe (tubing, point D) where it enters. Oil produced from the reservoir (point F) and injected gas

  6. POPULATION DENSITY, 2000 Population density measures the number

    E-Print Network [OSTI]

    Columbia University

    ´ GUADELOUPE 0 25 50 km NETHERLAND ANTILLES NETHERLAND ANTILLES ST. KITTS NEVIS Copyright 2009. The Trustees

  7. Effect of Crude Oil and Chemical Additives on Metabolic Activity of Mixed Microbial Populations in Fresh Marsh Soils

    E-Print Network [OSTI]

    Nyman, John

    Effect of Crude Oil and Chemical Additives on Metabolic Activity of Mixed Microbial Populations remineralization rates. Crude oil, which is known to contain toxins and reduce microbial diversity organic matter (Panicum hemitomon Shult. or Sagittaria lancifolia L. dominated marshes), crude oil

  8. Current Activities Assessing Butt Fusion Joint Integrity in High Density Polyethylene Piping

    SciTech Connect (OSTI)

    Crawford, Susan L.; Cinson, Anthony D.; Doctor, Steven R.; Denslow, Kayte M.

    2012-09-01T23:59:59.000Z

    The Pacific Northwest National Laboratory (PNNL) in Richland, Washington, conducted initial studies to evaluate the effectiveness of nondestructive examinations (NDE) coupled with mechanical testing for assessing butt fusion joint integrity in high density polyethylene (HDPE) pipe. The work provided insightful information to the United States Nuclear Regulatory Commission (NRC) on the effectiveness of volumetric inspection techniques for detecting lack of fusion (LOF) conditions in the fusion joints. HDPE has been installed on a limited basis in American Society of Mechanical Engineers (ASME) Class 3, buried piping systems at several operating U.S. nuclear power plants and has been proposed for use in new construction. A comparison was made between the results from ultrasonic and microwave nondestructive examinations and the results from mechanical destructive evaluations, specifically the high-speed tensile test and the side-bend test, for determining joint integrity. The data comparison revealed that none of the NDE techniques detected all of the lack-of-fusion conditions that were revealed by the destructive tests. Follow-on work has recently been initiated at PNNL to accurately characterize the NDE responses from machined flaws of varying size and location in PE 4710 materials as well as the LOF condition. This effort is directed at quantifying the ability of volumetric NDE techniques to detect flaws in relation to the critical flaw size associated with joint integrity. A status of these latest investigations is presented.

  9. Modeling high-pressure adsorption of gas mixtures on activated carbon and coal using a simplified local-density model

    SciTech Connect (OSTI)

    Fitzgerald, J.E.; Robinson, R.L.; Gasem, K.A.M. [Oklahoma State University, Stillwater, OK (United States). School of Chemical Engineering

    2006-11-07T23:59:59.000Z

    The simplified local-density (SLD) theory was investigated regarding its ability to provide accurate representations and predictions of high-pressure supercritical adsorption isotherms encountered in coalbed methane (CBM) recovery and CO{sub 2} sequestration. Attention was focused on the ability of the SLD theory to predict mixed-gas adsorption solely on the basis of information from pure gas isotherms using a modified Peng-Robinson (PR) equation of state (EOS). An extensive set of high-pressure adsorption measurements was used in this evaluation. These measurements included pure and binary mixture adsorption measurements for several gas compositions up to 14 MPa for Calgon F-400 activated carbon and three water-moistened coals. Also included were ternary measurements for the activated carbon and one coal. For the adsorption of methane, nitrogen, and CO{sub 2} on dry activated carbon, the SLD-PR can predict the component mixture adsorption within about 2.2 times the experimental uncertainty on average solely on the basis of pure-component adsorption isotherms. For the adsorption of methane, nitrogen, and CO{sub 2} on two of the three wet coals, the SLD-PR model can predict the component adsorption within the experimental uncertainties on average for all feed fractions (nominally molar compositions of 20/80, 40/60, 60/40, and 80/20) of the three binary gas mixture combinations, although predictions for some specific feed fractions are outside of their experimental uncertainties.

  10. Synthesising evidence for equity impacts of population-based physical activity interventions: a pilot study

    E-Print Network [OSTI]

    Humphreys, David K; Ogilvie, David

    2013-06-15T23:59:59.000Z

    WC, Merlo A, Gewa C, Weber MD, et al. The Los Angeles Lift Off: a sociocultural environmental change intervention to integrate physical activity into the workplace. Preventive Medicine. 2004;38(6):848-56. P43. Coleman KJ, Gonzalez EC. Promoting Stair... activity patterns among adolescents: a pilot study of 'Slice of Life'. Health education research. 1987 June 1, 1987;2(2):93-103. P54. Robinson TN. Reducing children's television viewing to prevent obesity. JAMA: the journal of the American Medical...

  11. 59S.A. BALAGUERA-REINA Y J.F. GONZLEZ-MAYA-POPULATION ECOLOGY OF C. ACUTUS IN VIPIS, MAGDALENA, COLOMBIA POPULATIONSTRUCTURE,DENSITY,ANDHABITATOF

    E-Print Network [OSTI]

    Nacional Autónoma de México, Universidad

    , COLOMBIA POPULATIONSTRUCTURE,DENSITY,ANDHABITATOF CROCODYLUS ACUTUS CUVIER 1807 IN THE VIA PARQUE ISLA DE SALAMANCA,MAGDALENADEPARTMENT,COLOMBIA SERGIO A. BALAGUERA-REINA1 AND JOSE F. GONZALEZ-MAYA1,2 1 Proyecto de Conservación deAguas y Tierras, ProCAT Colombia, Calle 127B # 45­76, Bogotá, Colombia. Abstract: Information

  12. A large population of mid-infrared selected, obscured active galaxies in the Bootes field

    E-Print Network [OSTI]

    R. C. Hickox; C. Jones; W. R. Forman; S. S. Murray; M. Brodwin; M. J. I. Brown; P. R. Eisenhardt; D. Stern; C. S. Kochanek; D. Eisenstein; R. J. Cool; B. T. Jannuzi; A. Dey; K. Brand; V. Gorjian; N. Caldwell

    2007-08-27T23:59:59.000Z

    We identify a population of 640 obscured and 839 unobscured AGNs at redshifts 0.7Bootes. We select AGNs on the basis of Spitzer IRAC colors obtained by the IRAC Shallow Survey. Redshifts are obtained from optical spectroscopy or photometric redshift estimators. We classify the IR-selected AGNs as IRAGN 1 (unobscured) and IRAGN 2 (obscured) using a simple criterion based on the observed optical to mid-IR color, with a selection boundary of R-[4.5]=6.1, where R and [4.5] are the Vega magnitudes in the R and IRAC 4.5 micron bands, respectively. We verify this selection using X-ray stacking analyses with data from the Chandra XBootes survey, as well as optical photometry from NDWFS and spectroscopy from MMT/AGES. We show that (1) these sources are indeed AGNs, and (2) the optical/IR color selection separates obscured sources (with average N_H~3x10^22 cm^-2 obtained from X-ray hardness ratios, and optical colors and morphologies typical of galaxies) and unobscured sources (with no X-ray absorption, and quasar colors and morphologies), with a reliability of >~80%. The observed numbers of IRAGNs are comparable to predictions from previous X-ray, optical, and IR luminosity functions, for the given redshifts and IRAC flux limits. We observe a bimodal distribution in R-[4.5] color, suggesting that luminous IR-selected AGNs have either low or significant dust extinction, which may have implications for models of AGN obscuration.

  13. STELLAR POPULATIONS IN THE CENTRAL 0.5 pc OF THE GALAXY. I. A NEW METHOD FOR CONSTRUCTING LUMINOSITY FUNCTIONS AND SURFACE-DENSITY PROFILES

    SciTech Connect (OSTI)

    Do, T.; Martinez, G. D. [Physics and Astronomy Department, University of California, Irvine, CA 92697 (United States)] [Physics and Astronomy Department, University of California, Irvine, CA 92697 (United States); Lu, J. R. [Institute for Astronomy, University of Hawaii, HI (United States)] [Institute for Astronomy, University of Hawaii, HI (United States); Ghez, A. M.; Morris, M. R.; Yelda, S. [Physics and Astronomy Department, University of California, Los Angeles, CA 90095-1547 (United States)] [Physics and Astronomy Department, University of California, Los Angeles, CA 90095-1547 (United States); Wright, S. A. [Dunlap Institute for Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Toronto M5S 3H4, ON (Canada)] [Dunlap Institute for Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Toronto M5S 3H4, ON (Canada); Matthews, K., E-mail: do@di.utoronto.ca [Department of Physics, Mathematics, and Astronomy, California Institute of Technology, Pasadena, CA (United States)

    2013-02-20T23:59:59.000Z

    We present new high angular resolution near-infrared spectroscopic observations of the nuclear star cluster surrounding the Milky Way's central supermassive black hole. Using the integral-field spectrograph OSIRIS on Keck II behind the laser-guide-star adaptive optics system, this spectroscopic survey enables us to separate early-type (young, 4-6 Myr) and late-type (old, >1 Gyr) stars with a completeness of 50% down to K' = 15.5 mag, which corresponds to {approx}10 M {sub Sun} for the early-type stars. This work increases the radial extent of reported OSIRIS/Keck measurements by more than a factor of three from 4'' to 14'' (0.16 to 0.56 pc), along the projected disk of young stars. For our analysis, we implement a new method of completeness correction using a combination of star-planting simulations and Bayesian inference. We assign probabilities for the spectral type of every source detected in deep imaging down to K' = 15.5 mag using information from spectra, simulations, number counts, and the distribution of stars. The inferred radial surface-density profiles, {Sigma}(R){proportional_to}R {sup -{Gamma}}, for the young stars and late-type giants are consistent with earlier results ({Gamma}{sub early} = 0.93 {+-} 0.09, {Gamma}{sub late} = 0.16 {+-} 0.07). The late-type surface-density profile is approximately flat out to the edge of the survey. While the late-type stellar luminosity function is consistent with the Galactic bulge, the completeness-corrected luminosity function of the early-type stars has significantly more young stars at faint magnitudes compared with previous surveys with similar depth. This luminosity function indicates that the corresponding mass function of the young stars is likely less top-heavy than that inferred from previous surveys.

  14. Dietary, Physical Activity, and Sedentary Behaviors and Their Relationship to Weight Gain in a College Age Population

    E-Print Network [OSTI]

    Lee, Faegen Dillon

    2012-10-19T23:59:59.000Z

    ix LIST OF FIGURES Page Figure 1 Weight vs days of 30+ minutes of physical activity ------------------------------ 49 Figure 2 BMI vs days of 30+ minutes of physical activity --------------------------------- 50 Figure 3 BMI difference vs days... --------------------------------------------- 45 Table 8 Physical activity and self-reported weight loss ----------------------------------- 47 Table 9 Days of 30+ minutes of physical activity and BMI ------------------------------ 48 Table 10 Days of 30+ minutes of physical activity...

  15. Populations Population Ecology

    E-Print Network [OSTI]

    Dever, Jennifer A.

    - species interactions Abiotic factors: l Climate l Temperature l Moisture l Wind l Soil l Fire Biotic- ? mortality increases as population size increases or birth rate decreases" l Negative feedback

  16. annual plant populations: Topics by E-print Network

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

    DEMOGRAPHY IN PLANTAGO:VARIATION AMONG COHORTS IN A NATURAL PLANT POPULATION DEBORAH A Roach,. Deborah 67 PLANT-ANIMAL INTERACTIONS -ORIGINAL PAPER Population density of North...

  17. DATA SHARING REPORT CHARACTERIZATION OF POPULATION 7: PERSONAL PROTECTIVE EQUIPMENT, DRY ACTIVE WASTE, AND MISCELLANEOUS DEBRIS, SURVEILLANCE AND MAINTENANCE PROJECT OAK RIDGE NATIONAL LABORATORY OAK RIDGE, TENNESSEE

    SciTech Connect (OSTI)

    Harpenau, Evan M

    2013-10-10T23:59:59.000Z

    The U.S. Department of Energy (DOE) Oak Ridge Office of Environmental Management (EM-OR) requested that Oak Ridge Associated Universities (ORAU), working under the Oak Ridge Institute for Science and Education (ORISE) contract, provide technical and independent waste management planning support under the American Recovery and Reinvestment Act (ARRA). Specifically, DOE EM-OR requested that ORAU plan and implement a sampling and analysis campaign targeting certain URS|CH2M Oak Ridge, LLC (UCOR) surveillance and maintenance (S&M) process inventory waste. Eight populations of historical and reoccurring S&M waste at the Oak Ridge National Laboratory (ORNL) have been identified in the Waste Handling Plan for Surveillance and Maintenance Activities at the Oak Ridge National Laboratory, DOE/OR/01-2565&D2 (WHP) (DOE 2012) for evaluation and processing to determine a final pathway for disposal. Population 7 (POP 7) consists of 56 containers of aged, low-level and potentially mixed S&M waste that has been staged in various locations around ORNL. Several of these POP 7 containers primarily contain personal protective equipment (PPE) and dry active waste (DAW), but may contain other miscellaneous debris. This data sharing report addresses the Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA) specified waste in a 13-container subpopulation (including eight steel boxes, three 55-gal drums, one sealand, and one intermodal) that lacked sufficient characterization data for possible disposal at the Environmental Management Waste Management Facility (EMWMF) using the approved Waste Lot (WL) 108.1 profile.

  18. CONTROL OF POPULATION DENSITIES SURROUNDING NUCLEAR POWER PLANTS. VOLUME 5 OF THE FINAL REPORT ON HEALTH AND SAFETY IMPACTS OF NUCLEAR, GEOTHERMAL, AND FOSSIL-FUEL ELECTRIC GENERATION IN CALIFORNIA

    E-Print Network [OSTI]

    Nero, jA.V.

    2010-01-01T23:59:59.000Z

    Related Standards for Nuclear Power Plants," by A.V. NeroResponse Planning for Nuclear Power Plants in California,"Densities Surrounding Nuclear Power Plants," by A.V. Nero,

  19. We do not explicitly consider heterogeneity in sexual activity, although the results are robust to consideration of contact networks and stratification of the population (see

    E-Print Network [OSTI]

    Weeks, Eric R.

    .1038/nature03072. 1. Bjornstad, O. N. & Grenfell, B. T. Noisy clockwork: Time series analysis of population

  20. Impact of entrainment and impingement on fish populations in the Hudson River Estuary. Volume II. Impingement impact analyses, evaluations of alternative screening devices, and critiques of utility testimony relating to density-dependent growth, the age-composition of the striped bass spawning stock, and the LMS real-time life cycle model

    SciTech Connect (OSTI)

    Barnthouse, L. W.; Van Winkle, W.; Golumbek, J.; Cada, G. F.; Goodyear, C. P.; Christensen, S. W.; Cannon, J. B.; Lee, D. W.

    1982-04-01T23:59:59.000Z

    This volume includes a series of four exhibits relating to impacts of impingement on fish populations, together with a collection of critical evaluations of testimony prepared for the utilities by their consultants. The first exhibit is a quantitative evaluation of four sources of bias (collection efficiency, reimpingement, impingement on inoperative screens, and impingement survival) affecting estimates of the number of fish killed at Hudson River power plants. The two following exhibits contain, respectively, a detailed assessment of the impact of impingement on the Hudson River white perch population and estimates of conditional impingement mortality rates for seven Hudson River fish populations. The fourth exhibit is an evaluation of the engineering feasibility and potential biological effectiveness of several types of modified intake structures proposed as alternatives to cooling towers for reducing impingement impacts. The remainder of Volume II consists of critical evaluations of the utilities' empirical evidence for the existence of density-dependent growth in young-of-the-year striped bass and white perch, of their estimate of the age-composition of the striped bass spawning stock in the Hudson River, and of their use of the Lawler, Matusky, and Skelly (LMS) Real-Time Life Cycle Model to estimate the impact of entrainment and impingement on the Hudson River striped bass population.

  1. E-Print Network 3.0 - adult stocking density Sample Search Results

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

    search results for: adult stocking density Page: << < 1 2 3 4 5 > >> 1 Population Ecology: A Simple Model of a Grasshopper Population In a text on Population Ecology, Begon...

  2. Studies of protein adsorption on implant materials in relation to biofilm formation I. Activity of Pseudomonas aeruginosa on Polypropylene and High density Polyethylene in presence of serum albumin

    E-Print Network [OSTI]

    Sinha, S Dutta; Maity, P K; Tarafdar, S; Moulik, S P

    2014-01-01T23:59:59.000Z

    The surface of biomaterials used as implants are highly susceptible to bacterial colonization and subsequent infection. The amount of protein adsorption on biomaterials, among other factors, can affect the nature and quality of biofilms formed on them. The variation in the adsorption time of the protein on the biomaterial surface produces a phenotypic change in the bacteria by alteration of the production of EPS (exoplysaccharide) matrix. Knowledge of the effects of protein adsorption on implant infection will be very useful in understanding the chemistry of the biomaterial surfaces, which can deter the formation of biofilms. It is observed that the adsorption of BSA on the biomaterial surfaces increases with time and concentration, irrespective of their type and the nature of the EPS matrix of the bacterial biofilm is dependent on the amount of protein adsorbed on the biomaterial surface. The adsorption of protein (BSA) on the biomaterials, polypropylene (PP) and high density polyethylene (HDPE) has been stu...

  3. MICROBIAL POPULATIONS FECAL PELLETS AND

    E-Print Network [OSTI]

    Luther, Douglas S.

    MICROBIAL POPULATIONS FECAL PELLETS AND AND BIOLU}IINESCENCEOF OCEANIC SEDII,IENTTRAP PARTICLES activities of microbial populations associated with fecal pellets col-Lecteo from oceanic zooplankton were (indicators of microbial growth and reproduction rates, respectively) were monitored in fecal pellets at time

  4. Density Functional Study of the Structure, Stability and Oxygen...

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

    Study of the Structure, Stability and Oxygen Reduction Activity of Ultrathin Platinum Nanowires. Density Functional Study of the Structure, Stability and Oxygen Reduction Activity...

  5. E-Print Network 3.0 - adult urban population Sample Search Results

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

    is found. The Neoclassic... Population Density model...126 18a. ... Source: Lund, Jay R. - Department of Civil and Environmental Engineering,...

  6. Studies of protein adsorption on implant materials in relation to biofilm formation I. Activity of Pseudomonas aeruginosa on Polypropylene and High density Polyethylene in presence of serum albumin

    E-Print Network [OSTI]

    S Dutta Sinha; Susmita Chatterjee; P. K. Maity; S. Tarafdar; S. P. Moulik

    2014-11-19T23:59:59.000Z

    The surface of biomaterials used as implants are highly susceptible to bacterial colonization and subsequent infection. The amount of protein adsorption on biomaterials, among other factors, can affect the nature and quality of biofilms formed on them. The variation in the adsorption time of the protein on the biomaterial surface produces a phenotypic change in the bacteria by alteration of the production of EPS (exoplysaccharide) matrix. Knowledge of the effects of protein adsorption on implant infection will be very useful in understanding the chemistry of the biomaterial surfaces, which can deter the formation of biofilms. It is observed that the adsorption of BSA on the biomaterial surfaces increases with time and concentration, irrespective of their type and the nature of the EPS matrix of the bacterial biofilm is dependent on the amount of protein adsorbed on the biomaterial surface. The adsorption of protein (BSA) on the biomaterials, polypropylene (PP) and high density polyethylene (HDPE) has been studied and the formation of the biofilms of Pseudomonas aeruginosa on them has been examined.

  7. Occupational Populations

    E-Print Network [OSTI]

    unknown authors

    ? The general population may be exposed to radon in indoor and outdoor air and drinking water. ? The primary source of indoor radon is from soil; radon in the soil can enter the home through cracks in the floors, walls, or foundations. The release of radon from water may also contribute to indoor levels. ? Exposures to radon gas are accompanied by exposure to radon progeny which are the decay products of radon-222 [e.g., bismuth-214 ( 214 Bi), lead-210 ( 210 Pb), 214 Pb, polonium-210 ( 210 Po), and 218 Po.

  8. Pair densities in density functional theory

    E-Print Network [OSTI]

    Chen, Huajie

    2015-01-01T23:59:59.000Z

    The exact interaction energy of a many-electron system is determined by the electron pair density, which is not well-approximated in standard Kohn-Sham density functional models. Here we study the (complicated but well-defined) exact universal map from density to pair density. We show that many common functionals, including the most basic version of the LDA (Dirac exchange with no correlation contribution), arise from particular approximations of this map. We develop an algorithm to compute the map numerically, and apply it to one-parameter families {a*rho(a*x)} of one-dimensional homogeneous and inhomogeneous single-particle densities. We observe that the pair density develops remarkable multiscale patterns which strongly depend on both the particle number and the "width" 1/a of the single-particle density. The simulation results are confirmed by rigorous asymptotic results in the limiting regimes a>>1 and a<<1. For one-dimensional homogeneous systems, we show that the whole spectrum of patterns is rep...

  9. Separation of carbon nanotubes in density gradients

    DOE Patents [OSTI]

    Hersam, Mark C. (Evanston, IL); Stupp, Samuel I. (Chicago, IL); Arnold, Michael S. (Northbrook, IL)

    2012-02-07T23:59:59.000Z

    The separation of single-walled carbon nanotubes (SWNTs), by chirality and/or diameter, using centrifugation of compositions of SWNTs in and surface active components in density gradient media.

  10. Separation of carbon nanotubes in density gradients

    DOE Patents [OSTI]

    Hersam, Mark C. (Evanston, IL); Stupp, Samuel I. (Chicago, IL); Arnold, Michael S. (Northbrook, IL)

    2010-02-16T23:59:59.000Z

    The separation of single-walled carbon nanotubes (SWNTs), by chirality and/or diameter, using centrifugation of compositions of SWNTs in and surface active components in density gradient media.

  11. Overlap population density as an index of bond strength

    E-Print Network [OSTI]

    Gallagher, Michael James

    2012-06-07T23:59:59.000Z

    be eliminated. This is done by carrying out an orthogonal transformdtion on b, witn a known matrix U, viz. D = UAU' (10) Next~ M is constructed vis, the equation: M=V'D 'U (11) M transforms b to the unit matrix X: (12) Since: I ~1 MdM = U 'D PhU 'D U... on molecules of the same chemical i'amily as those under study, viz, R2-NN02, D. Thermal Decomposition of Nitramides Although estimates of the energies of bonds other than N-N, B?G. Gowcnlock, P. Jones and J. R. Majer~ Trans. Faraday Soc. ~7 23 (1981) RE...

  12. The relationships between net primary productivity, human population density

    E-Print Network [OSTI]

    Hansen, Andrew J.

    ). The rate of NPP is determined by the conversion of solar energy to plant matter via photosynthesis, NSW, 2640, Australia Correspondence: Gary Luck, Institute for Land, Water and Society, Charles Sturt University, PO Box 789, Albury, NSW, 2640, Australia. E-mail: galuck@csu.edu.au ABSTRACT Aim In this study, I

  13. Estimates of cetacean abundance, biomass, and population density are

    E-Print Network [OSTI]

    ) and in understanding the eco- logical role of cetaceans in marine ecosystems (Trites et al., 1997). Along the U.S. west., 1997). Large whales also die from ship strikes (Carretta et al., 2006). West coast cetaceans may be affected by anthropogenic sound (e.g., sonar, ship noise, and seismic surveys) and cli- mate change

  14. Fact #661: February 7, 2011 Population Density | Department of Energy

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Delicious Rank EERE:YearRound-UpHeat PumpRecord ofESPCofConstructionofFY 20112: July 19, 2010Energy 5:Fuelof1:

  15. Equation for liquid density

    SciTech Connect (OSTI)

    Yaws, C.L.; Yang, H.C.; Hopper, J.R.; Cawley, W.A. (Lamar Univ., Beaumont, TX (US))

    1991-01-01T23:59:59.000Z

    Saturated liquid densities for organic chemicals are given as functions of temperature using a modified Rackett equation.

  16. Urban characteristics attributable to density-driven tie formation

    E-Print Network [OSTI]

    Pan, Wei

    Motivated by empirical evidence on the interplay between geography, population density and societal interaction, we propose a generative process for the evolution of social structure in cities. Our analytical and simulation ...

  17. Population stability, cooperation, and the invasibility of the human species

    E-Print Network [OSTI]

    Brown, James H.

    a mechanism for these outcomes by modifying a simple density-dependent population model to allow varying populations expanded out of Africa and spread rapidly across the majority of the earth's land surfacePopulation stability, cooperation, and the invasibility of the human species Marcus J. Hamiltona

  18. Ecological factors and human threats both drive wildfowl population declines

    E-Print Network [OSTI]

    ; human population density. Correspondence Peter R. Long, Department of Biology and Biochemistry, Africa and Asia. Second, we use phylogenetic comparative analyses to test whether population size, globalEcological factors and human threats both drive wildfowl population declines P. R. Long1 , T. Sz

  19. Genotype-Imputation Accuracy across Worldwide Human Populations

    E-Print Network [OSTI]

    Rosenberg, Noah

    and South Asia, the Americas, Oceania, the Middle East, and Africa. For each population, we identified- density reference panels. Specifically, study samples have typically derived from populations of NorthernARTICLE Genotype-Imputation Accuracy across Worldwide Human Populations Lucy Huang,1,2,* Yun Li,1

  20. Exploring the faint source population at 15.7 GHz

    E-Print Network [OSTI]

    Whittam, Imogen Helen

    2014-10-07T23:59:59.000Z

    -expanding Euclidean Universe populated with non-evolving sources with number density n and luminosity L contains N = 4pind3/3 sources out to distance d. As the flux density (S) of each source is given by S = L/4pid2, the number of sources brighter than flux density...

  1. Causes and consequences of complex population dynamics in an annual plant, Cardamine pensylvanica

    SciTech Connect (OSTI)

    Crone, E.E.

    1995-11-08T23:59:59.000Z

    The relative importance of density-dependent and density-independent factors in determining the population dynamics of plants has been widely debated with little resolution. In this thesis, the author explores the effects of density-dependent population regulation on population dynamics in Cardamine pensylvanica, an annual plant. In the first chapter, she shows that experimental populations of C. pensylvanica cycled from high to low density in controlled constant-environment conditions. These cycles could not be explained by external environmental changes or simple models of direct density dependence (N{sub t+1} = f[N{sub t}]), but they could be explained by delayed density dependence (N{sub t+1} = f[N{sub t}, N{sub t+1}]). In the second chapter, she shows that the difference in the stability properties of population growth models with and without delayed density dependence is due to the presence of Hopf as well as slip bifurcations from stable to chaotic population dynamics. She also measures delayed density dependence due to effects of parental density on offspring quality in C. pensylvanica and shows that this is large enough to be the cause of the population dynamics observed in C. pensylvanica. In the third chapter, the author extends her analyses of density-dependent population growth models to include interactions between competing species. In the final chapter, she compares the effects of fixed spatial environmental variation and variation in population size on the evolutionary response of C. pensylvanica populations.

  2. Statistical inference for density dependent Markovian forestry models

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Statistical inference for density dependent Markovian forestry models Abstract A stochastic forestry model with a density-dependence structure is studied. The population evolves in discrete roughly speaking, becomes large. From the perspective of the analysis of forestry data and predict

  3. Density-dependent covariant energy density functionals

    SciTech Connect (OSTI)

    Lalazissis, G. A. [Physics Department, Aristotle University of Thessaloniki, GR-54124 (Greece)

    2012-10-20T23:59:59.000Z

    Relativistic nuclear energy density functionals are applied to the description of a variety of nuclear structure phenomena at and away fromstability line. Isoscalar monopole, isovector dipole and isoscalar quadrupole giant resonances are calculated using fully self-consistent relativistic quasiparticle randomphase approximation, based on the relativistic Hartree-Bogoliubovmodel. The impact of pairing correlations on the fission barriers in heavy and superheavy nuclei is examined. The role of pion in constructing desnity functionals is also investigated.

  4. Independent optical excitation of distinct neural populations

    E-Print Network [OSTI]

    Klapoetke, Nathan Cao

    Optogenetic tools enable examination of how specific cell types contribute to brain circuit functions. A long-standing question is whether it is possible to independently activate two distinct neural populations in mammalian ...

  5. Statistical inference in population genetics using microsatellites

    E-Print Network [OSTI]

    Csillry, Katalin

    2009-01-01T23:59:59.000Z

    Statistical inference from molecular population genetic data is currently a very active area of research for two main reasons. First, in the past two decades an enormous amount of molecular genetic data have been produced ...

  6. Population Analysis, Fall 2005 1 Population Analyses

    E-Print Network [OSTI]

    Clark, William R.

    Population Analysis, Fall 2005 1 Population Analyses EEOB/AEcl 611 Fall Semester 2005 Scheduled Phone: 294-5176 email: wrclark@iastate.edu AEcl 611 is evolving in response to very rapid changes. The emphasis in AEcl 611 is on understanding the statistical basis of various analytical techniques, applying

  7. Density Matrix Topological Insulators

    E-Print Network [OSTI]

    A. Rivas; O. Viyuela; M. A. Martin-Delgado

    2013-10-31T23:59:59.000Z

    Thermal noise can destroy topological insulators (TI). However we demonstrate how TIs can be made stable in dissipative systems. To that aim, we introduce the notion of band Liouvillian as the dissipative counterpart of band Hamiltonian, and show a method to evaluate the topological order of its steady state. This is based on a generalization of the Chern number valid for general mixed states (referred to as density matrix Chern value), which witnesses topological order in a system coupled to external noise. Additionally, we study its relation with the electrical conductivity at finite temperature, which is not a topological property. Nonetheless, the density matrix Chern value represents the part of the conductivity which is topological due to the presence of quantum mixed edge states at finite temperature. To make our formalism concrete, we apply these concepts to the two-dimensional Haldane model in the presence of thermal dissipation, but our results hold for arbitrary dimensions and density matrices.

  8. Density Functional Theory for Superconductors

    E-Print Network [OSTI]

    Gross, E.K.U.

    Density Functional Theory for Superconductors LATHIOTAKIS, A. MARQUES, 1,2,3 LU DERS, L. FAST, 2004 words: theory superconductors; density functional theory; critical temperature; exchange matter physics theoretical chemistry is density functional theory (DFT). foundations were established mid

  9. Optimal Harvesting of Structured Populations*t WAYNE M. GETZ

    E-Print Network [OSTI]

    Getz, Wayne M.

    density of the population [denoted by x(t)] satisfies a nonlinear ordinary differential equationOptimal Harvesting of Structured Populations*t WAYNE M. GETZ National Research Institute for Mathematical Sciences, CSIR, P.O. Box 395, Pretoria 0001, Republic of South Africa Received 18 April 1978

  10. Tracing spiral density waves in M81

    E-Print Network [OSTI]

    S. Kendall; R. C. Kennicutt; C. Clarke; M. D. Thornley

    2008-04-15T23:59:59.000Z

    We use SPITZER IRAC 3.6 and 4.5micron near infrared data from the Spitzer Infrared Nearby Galaxies Survey (SINGS), optical B, V and I and 2MASS Ks band data to produce mass surface density maps of M81. The IRAC 3.6 and 4.5micron data, whilst dominated by emission from old stellar populations, is corrected for small-scale contamination by young stars and PAH emission. The I band data are used to produce a mass surface density map by a B-V colour-correction, following the method of Bell and de Jong. We fit a bulge and exponential disc to each mass map, and subtract these components to reveal the non-axisymmetric mass surface density. From the residual mass maps we are able to extract the amplitude and phase of the density wave, using azimuthal profiles. The response of the gas is observed via dust emission in the 8micron IRAC band, allowing a comparison between the phase of the stellar density wave and gas shock. The relationship between this angular offset and radius suggests that the spiral structure is reasonably long lived and allows the position of corotation to be determined.

  11. Multiple density layered insulator

    DOE Patents [OSTI]

    Alger, T.W.

    1994-09-06T23:59:59.000Z

    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.

  12. Multiple density layered insulator

    DOE Patents [OSTI]

    Alger, Terry W. (Tracy, CA)

    1994-01-01T23:59:59.000Z

    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.

  13. Energy in density gradient

    E-Print Network [OSTI]

    Vranjes, J

    2015-01-01T23:59:59.000Z

    Inhomogeneous plasmas and fluids contain energy stored in inhomogeneity and they naturally tend to relax into lower energy states by developing instabilities or by diffusion. But the actual amount of energy in such inhomogeneities has remained unknown. In the present work the amount of energy stored in a density gradient is calculated for several specific density profiles in a cylindric configuration. This is of practical importance for drift wave instability in various plasmas, and in particular in its application in models dealing with the heating of solar corona because the instability is accompanied with stochastic heating, so the energy contained in inhomogeneity is effectively transformed into heat. It is shown that even for a rather moderate increase of the density at the axis in magnetic structures in the corona by a factor 1.5 or 3, the amount of excess energy per unit volume stored in such a density gradient becomes several orders of magnitude greater than the amount of total energy losses per unit ...

  14. Gedanken densities and exact constraints in density functional theory

    SciTech Connect (OSTI)

    Perdew, John P. [Department of Physics, Temple University, Philadelphia, Pennsylvania 19122 (United States) [Department of Physics, Temple University, Philadelphia, Pennsylvania 19122 (United States); Department of Chemistry, Temple University, Philadelphia, Pennsylvania 19122 (United States); Ruzsinszky, Adrienn; Sun, Jianwei [Department of Physics, Temple University, Philadelphia, Pennsylvania 19122 (United States)] [Department of Physics, Temple University, Philadelphia, Pennsylvania 19122 (United States); Burke, Kieron [Department of Chemistry and Department of Physics, University of California, Irvine, California 92697 (United States)] [Department of Chemistry and Department of Physics, University of California, Irvine, California 92697 (United States)

    2014-05-14T23:59:59.000Z

    Approximations to the exact density functional for the exchange-correlation energy of a many-electron ground state can be constructed by satisfying constraints that are universal, i.e., valid for all electron densities. Gedanken densities are designed for the purpose of this construction, but need not be realistic. The uniform electron gas is an old gedanken density. Here, we propose a spherical two-electron gedanken density in which the dimensionless density gradient can be an arbitrary positive constant wherever the density is non-zero. The Lieb-Oxford lower bound on the exchange energy can be satisfied within a generalized gradient approximation (GGA) by bounding its enhancement factor or simplest GGA exchange-energy density. This enhancement-factor bound is well known to be sufficient, but our gedanken density shows that it is also necessary. The conventional exact exchange-energy density satisfies no such local bound, but energy densities are not unique, and the simplest GGA exchange-energy density is not an approximation to it. We further derive a strongly and optimally tightened bound on the exchange enhancement factor of a two-electron density, which is satisfied by the local density approximation but is violated by all published GGA's or meta-GGAs. Finally, some consequences of the non-uniform density-scaling behavior for the asymptotics of the exchange enhancement factor of a GGA or meta-GGA are given.

  15. E-Print Network 3.0 - active conductance states Sample Search...

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

    Collection: Mathematics 4 Neurocomputing 6566 (2005) 673678 Reconstructing synaptic background activity Summary: Population activity Down-state Intracellular activity...

  16. Estimating Traveler Populations at Airport and Cruise Terminals for Population Distribution and Dynamics

    SciTech Connect (OSTI)

    Jochem, Warren C [ORNL; Sims, Kelly M [ORNL; Bright, Eddie A [ORNL; Urban, Marie L [ORNL; Rose, Amy N [ORNL; Coleman, Phil R [ORNL; Bhaduri, Budhendra L [ORNL

    2013-01-01T23:59:59.000Z

    In recent years, uses of high-resolution population distribution databases are increasing steadily for environmental, socioeconomic, public health, and disaster-related research and operations. With the development of daytime population distribution, temporal resolution of such databases has been improved. However, the lack of incorporation of transitional population, namely business and leisure travelers, leaves a significant population unaccounted for within the critical infrastructure networks, such as at transportation hubs. This paper presents two general methodologies for estimating passenger populations in airport and cruise port terminals at a high temporal resolution which can be incorporated into existing population distribution models. The methodologies are geographically scalable and are based on, and demonstrate how, two different transportation hubs with disparate temporal population dynamics can be modeled utilizing publicly available databases including novel data sources of flight activity from the Internet which are updated in near-real time. The airport population estimation model shows great potential for rapid implementation for a large collection of airports on a national scale, and the results suggest reasonable accuracy in the estimated passenger traffic. By incorporating population dynamics at high temporal resolutions into population distribution models, we hope to improve the estimates of populations exposed to or at risk to disasters, thereby improving emergency planning and response, and leading to more informed policy decisions.

  17. High Energy Density Capacitors

    SciTech Connect (OSTI)

    None

    2010-07-01T23:59:59.000Z

    BEEST Project: Recapping is developing a capacitor that could rival the energy storage potential and price of todays best EV batteries. When power is needed, the capacitor rapidly releases its stored energy, similar to lightning being discharged from a cloud. Capacitors are an ideal substitute for batteries if their energy storage capacity can be improved. Recapping is addressing storage capacity by experimenting with the material that separates the positive and negative electrodes of its capacitors. These separators could significantly improve the energy density of electrochemical devices.

  18. Gluon density in nuclei

    SciTech Connect (OSTI)

    Ayala, A.L. [Rio Grande do Sul Univ., Porto Alegre, RS (Brazil). Inst. de Fisica][Pelotas Univ., RS (Brazil). Inst. de Fisica e Matematica; Ducati, M.B.G. [Rio Grande do Sul Univ., Porto Alegre, RS (Brazil). Inst. de Fisica; Levin, E.M. [Fermi National Accelerator Lab., Batavia, IL (United States)][Nuclear Physics Inst., St. Petersburg (Russian Federation)

    1996-10-01T23:59:59.000Z

    In this talk we present our detailed study (theory and numbers) on the shadowing corrections to the gluon structure functions for nuclei. Starting from rather controversial information on the nucleon structure function which is originated by the recent HERA data, we develop the Glauber approach for the gluon density in a nucleus based on Mueller formula and estimate the value of the shadowing corrections in this case. Then we calculate the first corrections to the Glauber approach and show that these corrections are big. Based on this practical observation we suggest the new evolution equation which takes into account the shadowing corrections and solve it. We hope to convince you that the new evolution equation gives a good theoretical tool to treat the shadowing corrections for the gluons density in a nucleus and, therefore, it is able to provide the theoretically reliable initial conditions for the time evolution of the nucleus-nucleus cascade. The initial conditions should be fixed both theoretically and phenomenologically before to attack such complicated problems as the mixture of hard and soft processes in nucleus-nucleus interactions at high energy or the theoretically reliable approach to hadron or/and parton cascades for high energy nucleus-nucleus interaction. 35 refs., 24 figs., 1 tab.

  19. Estimating abundance for a savanna elephant population using markresight methods: a case study for the Tembe

    E-Print Network [OSTI]

    Pretoria, University of

    are difficult to count. Many elephant populations in Africa occur in such conditions. Estimates population size or densities for medium to large mammals living in wooded areas are poorly developed (CaroEstimating abundance for a savanna elephant population using mark­resight methods: a case study

  20. Assessing the distribution, habitat, and population size of the threatened Dupont's lark Chersophilus

    E-Print Network [OSTI]

    Oñate, Juan J.

    North African range, as well as on its preferred habitat, population density and size. Fieldwork), with important populations believed to be present in the steppe-like habitat of North Africa (Cramp, 1988Assessing the distribution, habitat, and population size of the threatened Dupont's lark

  1. Deriving Atmospheric Density Estimates Using Satellite Precision Orbit Ephemerides

    E-Print Network [OSTI]

    Hiatt, Andrew Timothy

    2009-01-01T23:59:59.000Z

    Model regardless of solar and geomagnetic activity levels. The POE density estimates were obtained with the desired accuracy for a 10% variation in the ballistic coefficient used to initialize the process. Fit span length showed little influence...

  2. Low density microcellular foams

    DOE Patents [OSTI]

    LeMay, James D. (Castro Valley, CA)

    1992-01-01T23:59:59.000Z

    Disclosed is a process of producing microcellular from which comprises the steps of: (a) selecting a multifunctional epoxy oligomer resin; (b) mixing said epoxy resin with a non-reactive diluent to form a resin-diluent mixture; (c) forming a diluent containing cross-linked epoxy gel from said resin-diluent mixture; (d) replacing said diluent with a solvent therefore; (e) replacing said solvent with liquid carbon dioxide; and (f) vaporizing off said liquid carbon dioxide under supercritical conditions, whereby a foam having a density in the range of 35-150 mg/cc and cell diameters less than about 1 .mu.m is produced. Also disclosed are the foams produced by the process.

  3. Low density microcellular foams

    DOE Patents [OSTI]

    LeMay, J.D.

    1991-11-19T23:59:59.000Z

    Disclosed is a process of producing microcellular foam which comprises the steps of: (a) selecting a multifunctional epoxy oligomer resin; (b) mixing said epoxy resin with a non-reactive diluent to form a resin-diluent mixture; (c) forming a diluent containing cross-linked epoxy gel from said resin-diluent mixture; (d) replacing said diluent with a solvent therefore; (e) replacing said solvent with liquid carbon dioxide; and (f) vaporizing off said liquid carbon dioxide under supercritical conditions, whereby a foam having a density in the range of 35-150 mg/cc and cell diameters less than about 1 [mu]m is produced. Also disclosed are the foams produced by the process. 8 figures.

  4. Low density microcellular foams

    DOE Patents [OSTI]

    LeMay, James D. (Castro Valley, CA)

    1991-01-01T23:59:59.000Z

    Disclosed is a process of producing microcellular foam which comprises the steps of: (a) selecting a multifunctional epoxy oligomer resin; (b) mixing said epoxy resin with a non-reactive diluent to form a resin-diluent mixture; (c) forming a diluent containing cross-linked epoxy gel from said resin-diluent mixture; (d) replacing said diluent with a solvent therefore; (e) replacing said solvent with liquid carbon dioxide; and (f) vaporizing off said liquid carbon dioxide under supercritical conditions, whereby a foam having a density in the range of 35-150 mg/cc and cell diameters less than about 1 .mu.m is produced. Also disclosed are the foams produced by the process.

  5. Density constrained TDHF

    E-Print Network [OSTI]

    Oberacker, V E

    2015-01-01T23:59:59.000Z

    In this manuscript we provide an outline of the numerical methods used in implementing the density constrained time-dependent Hartree-Fock (DC-TDHF) method and provide a few examples of its application to nuclear fusion. In this approach, dynamic microscopic calculations are carried out on a three-dimensional lattice and there are no adjustable parameters, the only input is the Skyrme effective NN interaction. After a review of the DC-TDHF theory and the numerical methods, we present results for heavy-ion potentials $V(R)$, coordinate-dependent mass parameters $M(R)$, and precompound excitation energies $E^{*}(R)$ for a variety of heavy-ion reactions. Using fusion barrier penetrabilities, we calculate total fusion cross sections $\\sigma(E_\\mathrm{c.m.})$ for reactions between both stable and neutron-rich nuclei. We also determine capture cross sections for hot fusion reactions leading to the formation of superheavy elements.

  6. Nuclear Energy Density Optimization

    E-Print Network [OSTI]

    M. Kortelainen; T. Lesinski; J. Mor; W. Nazarewicz; J. Sarich; N. Schunck; M. V. Stoitsov; S. Wild

    2010-05-27T23:59:59.000Z

    We carry out state-of-the-art optimization of a nuclear energy density of Skyrme type in the framework of the Hartree-Fock-Bogoliubov (HFB) theory. The particle-hole and particle-particle channels are optimized simultaneously, and the experimental data set includes both spherical and deformed nuclei. The new model-based, derivative-free optimization algorithm used in this work has been found to be significantly better than standard optimization methods in terms of reliability, speed, accuracy, and precision. The resulting parameter set UNEDFpre results in good agreement with experimental masses, radii, and deformations and seems to be free of finite-size instabilities. An estimate of the reliability of the obtained parameterization is given, based on standard statistical methods. We discuss new physics insights offered by the advanced covariance analysis.

  7. Density Functional Theory for Superconductors

    E-Print Network [OSTI]

    Gross, E.K.U.

    Density Functional Theory for Superconductors N. N. LATHIOTAKIS,1,2 M. A. L. MARQUES,1,2,3 M. LU; density functional theory; critical temperature; exchange and correlation; phonon and theoretical chemistry is density functional theory (DFT). Its foundations were established in the mid-1960s

  8. Longitudinal density monitor for the LHC

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

    Jeff, A.; Andersen, M.; Boccardi, A.; Bozyigit, S.; Bravin, E.; Lefevre, T.; Rabiller, A.; Roncarolo, F.; Welsch, C. P.; Fisher, A. S.

    2012-03-01T23:59:59.000Z

    The longitudinal density monitor (LDM) is primarily intended for the measurement of the particle population in nominally empty rf buckets. These so-called satellite or ghost bunches can cause problems for machine protection as well as influencing the luminosity calibration of the LHC. The high dynamic range of the system allows measurement of ghost bunches with as little as 0.01% of the main bunch population at the same time as characterization of the main bunches. The LDM is a single-photon counting system using visible synchrotron light. The photon detector is a silicon avalanche photodiode operated in Geiger mode, which allows the longitudinal distribution of the LHC beams to be measured with a resolution of 90 ps. Results from the LDM are presented, including a proposed method for constructing a 3-dimensional beam density map by scanning the LDM sensor in the transverse plane. In addition, we present a scheme to improve the sensitivity of the system by using an optical switching technique.

  9. Further Developments in Orbit Ephemeris Derived Neutral Density

    E-Print Network [OSTI]

    Locke, Travis Cole

    2012-12-31T23:59:59.000Z

    /04/2002. ................................... 91 Figure 4.4 Atmospheric Density Comparison for CHAMP on 04/17/2002. ................................... 92 Figure 4.5 Atmospheric Density Comparison for GRACE on 08/04/2006. .................................... 93 Figure 4.6 Atmospheric... sigma values. .... 88 Table 4.2 Average CC values for CHAMP binned by solar activity level. ..................................... 96 Table 4.3 Average RMS values (10-12 kg/m3) for CHAMP binned by solar activity level.............. 96 Table 4...

  10. Local thermodynamic equilibrium in rapidly heated high energy density plasmas

    SciTech Connect (OSTI)

    Aslanyan, V.; Tallents, G. J. [York Plasma Institute, Department of Physics, University of York, Heslington, York YO10 5DD (United Kingdom)

    2014-06-15T23:59:59.000Z

    Emission spectra and the dynamics of high energy density plasmas created by optical and Free Electron Lasers (FELs) depend on the populations of atomic levels. Calculations of plasma emission and ionization may be simplified by assuming Local Thermodynamic Equilibrium (LTE), where populations are given by the Saha-Boltzmann equation. LTE can be achieved at high densities when collisional processes are much more significant than radiative processes, but may not be valid if plasma conditions change rapidly. A collisional-radiative model has been used to calculate the times taken by carbon and iron plasmas to reach LTE at varying densities and heating rates. The effect of different energy deposition methods, as well as Ionization Potential Depression are explored. This work shows regimes in rapidly changing plasmas, such as those created by optical lasers and FELs, where the use of LTE is justified, because timescales for plasma changes are significantly longer than the times needed to achieve an LTE ionization balance.

  11. DERIVATION AND OBSERVABILITY OF UPPER ATMOSPHERIC DENSITY VARIATIONS UTILIZING PRECISION ORBIT EPHEMERIDES

    E-Print Network [OSTI]

    Lechtenberg, Travis Francis

    2010-04-28T23:59:59.000Z

    for these satellites. The POE derived densities showed marked improvement using these methods of comparison over the existing empirical density models for all examined time periods and solar and geomagnetic activity levels. The cross correlation values for the POE...

  12. Populating the Whole Landscape

    E-Print Network [OSTI]

    Adam R. Brown; Alex Dahlen

    2012-02-19T23:59:59.000Z

    Every de Sitter vacuum can transition to every other de Sitter vacuum despite any obstacle, despite intervening anti-de Sitter sinks, despite not being connected by an instanton. Eternal inflation populates the whole landscape.

  13. ATLBS EXTENDED SOURCE SAMPLE: THE EVOLUTION IN RADIO SOURCE MORPHOLOGY WITH FLUX DENSITY

    SciTech Connect (OSTI)

    Saripalli, L.; Subrahmanyan, R.; Thorat, K.; Ekers, R. D. [Raman Research Institute, C. V. Raman Avenue, Sadashivanagar, Bangalore 560080 (India); Hunstead, R. W.; Johnston, H. M.; Sadler, E. M., E-mail: lsaripal@rri.res.in [Sydney Institute for Astronomy, School of Physics, University of Sydney, NSW 2006 (Australia)

    2012-04-01T23:59:59.000Z

    Based on the Australia Telescope Low Brightness Survey (ATLBS) we present a sample of extended radio sources and derive morphological properties of faint radio sources. One hundred nineteen radio galaxies form the ATLBS Extended Source Sample (ATLBS-ESS) consisting of all sources exceeding 30'' in extent and integrated flux densities exceeding 1 mJy. We give structural details along with information on galaxy identifications and source classifications. The ATLBS-ESS, unlike samples with higher flux-density limits, has almost equal fractions of FR-I and FR-II radio galaxies, with a large fraction of the FR-I population exhibiting 3C31-type structures. Significant asymmetry in lobe extents appears to be a common occurrence in the ATLBS-ESS FR-I sources compared with FR-II sources. We present a sample of 22 FR-Is at z > 0.5 with good structural information. The detection of several giant radio sources, with size exceeding 0.7 Mpc, at z > 1 suggests that giant radio sources are not less common at high redshifts. The ESS also includes a sample of 28 restarted radio galaxies. The relative abundance of dying and restarting sources is indicative of a model where radio sources undergo episodic activity in which an active phase is followed by a brief dying phase that terminates with restarting of the central activity; in any massive elliptical a few such activity cycles wherein adjacent events blend may constitute the lifetime of a radio source and such bursts of blended activity cycles may be repeated over the age of the host. The ATLBS-ESS includes a 2 Mpc giant radio galaxy with the lowest surface brightness lobes known to date.

  14. Canonical density matrix perturbation theory

    E-Print Network [OSTI]

    Niklasson, Anders M N; Rubensson, Emanuel H; Rudberg, Elias

    2015-01-01T23:59:59.000Z

    Density matrix perturbation theory [Niklasson and Challacombe, Phys. Rev. Lett. 92, 193001 (2004)] is generalized to canonical (NVT) free energy ensembles in tight-binding, Hartree-Fock or Kohn-Sham density functional theory. The canonical density matrix perturbation theory can be used to calculate temperature dependent response properties from the coupled perturbed self-consistent field equations as in density functional perturbation theory. The method is well suited to take advantage of sparse matrix algebra to achieve linear scaling complexity in the computational cost as a function of system size for sufficiently large non-metallic materials and metals at high temperatures.

  15. Generation of Gaussian Density Fields

    E-Print Network [OSTI]

    Hugo Martel

    2005-07-15T23:59:59.000Z

    This document describes analytical and numerical techniques for the generation of Gaussian density fields, which represent cosmological density perturbations. The mathematical techniques involved in the generation of density harmonics in k-space, the filtering of the density fields, and the normalization of the power spectrum to the measured temperature fluctuations of the Cosmic Microwave Background, are presented in details. These techniques are well-known amongst experts, but the current literature lacks a formal description. I hope that this technical report will prove useful to new researchers moving into this field, sparing them the task of reinventing the wheel.

  16. Density Functional Theory (DFT) Simulated Annealing (SA)

    E-Print Network [OSTI]

    . . . . . . . . 9 2009 #12;! " # $ % & - " # $ %' ! " # # $ % & # ( # " ) Density Functional Theory) % Lattice-Boltzmann (LBM) #12;! " # $ % & - " # $ %' ! " # # $ % & # ( # " ) Density Functional Theory (DFT;! " # $ % & - " # $ %' ! " # # $ % & # ( # " ) Density Functional Theory (DFT) Simulated Annealing (SA) Monte Carlo &$ ' ' (GCMC

  17. Detecting Density Variations and Nanovoids

    SciTech Connect (OSTI)

    Miller, Michael K [ORNL; Longstreth-Spoor, L. [Washington University, St. Louis; Kelton, K. F. [Washington University, St. Louis

    2011-01-01T23:59:59.000Z

    A combination of simulated and experimental data has been used to investigate the size range of nanovoids that can be detected in atom probe tomography data. Simulated atom probe tomography data have revealed that nanovoids as small as 1 nm in diameter can be detected in atom probe tomography data with the use of iso-density surfaces. Iso-density surfaces may be used to quantify the size, morphology and number density of nanovoids and other variations in density in atom probe tomography data. Experimental data from an aluminum-yttrium-iron metallic glass ribbon have revealed the effectiveness of this approach. Combining iso-density surfaces with atom maps also permits the segregation of solute to the nanovoids to be investigated. Field ion microscopy and thin section atom maps have also been used to detect pores and larger voids.

  18. Climate Activity 1 Frontiers of Science Seminar Activity Following Broecker's First Lecture

    E-Print Network [OSTI]

    Menke, William

    . World Population. The reddest color corresponds to a population density of 1000 people per square populated (reddish) band crossing Africa just south of the Sahara desert. By correlating this region. The great rain forests of Brazil and equatorial Africa are dark green. The band of forests running across

  19. Population Ecology Philip M. Dixon

    E-Print Network [OSTI]

    Population Ecology Philip M. Dixon Department of Statistics Iowa State University 20 December 2001 Population ecology is the discipline in ecology that deals with the structure and dynamics (e.g. growth interacting populations. Population ecology is closely related to other ecological disciplines, e

  20. Molecular population genetics and epidemiology of Ceratocystis fagacearum

    E-Print Network [OSTI]

    Ivors, Kelly Lynn

    1995-01-01T23:59:59.000Z

    and the other population represented a sexually active disease center. Three polymorphic RFLP loci were found. Only one population, Willow Springs, had more than 1 allele present at the RFLP loci. Very low levels of variation (G = 1, 1, and 11.69) were detected...

  1. Density and pair-density scaling for deriving the Euler equation in density-functional and pair-density-functional theory

    SciTech Connect (OSTI)

    Nagy, A. [Department of Theoretical Physics, University of Debrecen, H-4010 Debrecen (Hungary)

    2011-09-15T23:59:59.000Z

    A link between density and pair density functional theories is presented. Density and pair density scaling are used to derive the Euler equation in both theories. Density scaling provides a constructive way of obtaining approximations for the Pauli potential. The Pauli potential (energy) of the density functional theory is expressed as the difference of the scaled and original exchange-correlation potentials (energies).

  2. Phenomenological Relativistic Energy Density Functionals

    SciTech Connect (OSTI)

    Lalazissis, G. A.; Kartzikos, S. [Physics Department, Aristotle University of Thessaloniki (Greece); Niksic, T.; Paar, N.; Vretenar, D. [Physics Department, University of Zagreb (Croatia); Ring, P. [Physics Department, TU Muenchen, Garching (Germany)

    2009-08-26T23:59:59.000Z

    The framework of relativistic nuclear energy density functionals is applied to the description of a variety of nuclear structure phenomena, not only in spherical and deformed nuclei along the valley of beta-stability, but also in exotic systems with extreme isospin values and close to the particle drip-lines. Dynamical aspects of exotic nuclear structure is explored using the fully consistent quasiparticle random-phase approximation based on the relativistic Hartree-Bogoliubov model. Recent applications of energy density functionals with explicit density dependence of the meson-nucleon couplings are presented.

  3. COLOR DISTRIBUTIONS, NUMBER, AND MASS DENSITIES OF MASSIVE GALAXIES AT 1.5 < z < 3: COMPARING OBSERVATIONS WITH MERGER SIMULATIONS

    SciTech Connect (OSTI)

    Wuyts, Stijn; Cox, Thomas J.; Hayward, Christopher C.; Hernquist, Lars [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Franx, Marijn [Leiden University, Leiden Observatory, P.O. Box 9513, NL-2300 RA, Leiden (Netherlands); Foerster Schreiber, Natascha M. [MPE, Giessenbackstrasse, D-85748 Garching (Germany); Hopkins, Philip F. [Department of Astronomy, University of California Berkeley, Berkeley, CA 94720 (United States); Labbe, Ivo [Carnegie Observatories, 813 Santa Barbara Street, Pasadena, CA 91101 (United States); Marchesini, Danilo; Van Dokkum, Pieter G. [Department of Astronomy, Yale University, New Haven, CT 06520-8101 (United States); Robertson, Brant E. [Kavli Institute for Cosmological Physics, and Department of Astronomy and Astrophysics, University of Chicago, Chicago, IL 60637 (United States); Toft, Sune [European Southern Observatory, Karl-Schwarzschild-Str. 2, D-85748 Garching bei Muenchen (Germany)

    2009-07-20T23:59:59.000Z

    We present a comparison between the observed color distribution, number, and mass density of massive galaxies at 1.5 < z < 3 and a model by Hopkins et al. that relates the quasar and galaxy population on the basis of gas-rich mergers. In order to test the hypothesis that quiescent red galaxies are formed after a gas-rich merger involving quasar activity, we confront photometry of massive (M>4 x 10{sup 10} M{sub sun}) galaxies extracted from the FIRES, GOODS-South, and MUSYC surveys, together spanning an area of 496 arcmin{sup 2}, with synthetic photometry from hydrodynamical merger simulations. As in the Hopkins et al. model, we use the observed quasar luminosity function to estimate the merger rate. We find that the synthetic U - V and V - J colors of galaxies that had a quasar phase in their past match the colors of observed galaxies that are best characterized by a quiescent stellar population. At z {approx} 2.6, the observed number and mass density of quiescent red galaxies with M>4 x 10{sup 10} M{sub sun} is consistent with the model in which every quiescent massive galaxy underwent a quasar phase in the past. At z {approx} 1.9, 2.8 times less quiescent galaxies are observed than predicted by the model as descendants of higher redshift quasars. The merger model also predicts a large number and mass density of galaxies undergoing star formation driven by the merger. We find that the predicted number and mass density accounts for 30%-50% of the observed massive star-forming galaxies. However, their colors do not match those of observed star-forming galaxies. In particular, the colors of dusty red galaxies (accounting for 30%-40% of the massive galaxy population) are not reproduced by the simulations. Several possible origins of this discrepancy are discussed. The observational constraints on the validity of the model are currently limited by cosmic variance and uncertainties in stellar population synthesis and radiative transfer.

  4. Dynamical density functional theory for colloidal particles with arbitrary shape

    E-Print Network [OSTI]

    Raphael Wittkowski; Hartmut Lwen

    2011-06-12T23:59:59.000Z

    Starting from the many-particle Smoluchowski equation, we derive dynamical density functional theory for Brownian particles with an arbitrary shape. Both passive and active (self-propelled) particles are considered. The resulting theory constitutes a microscopic framework to explore the collective dynamical behavior of biaxial particles in nonequilibrium. For spherical and uniaxial particles, earlier derived dynamical density functional theories are recovered as special cases. Our study is motivated by recent experimental progress in preparing colloidal particles with many different biaxial shapes.

  5. The value of density measurements in stellar coronae

    E-Print Network [OSTI]

    Jan-Uwe Ness; Carole Jordan

    2005-04-06T23:59:59.000Z

    The grating instruments on board Chandra and XMM-Newton now allow measurements of electron densities. These rely on the ratios of fluxes in emission lines, where one line depends on both collisional and radiative decay rates. The electron density is required to constrain the physical extent of the emitting region, and large samples of measurements are of interest in the context of trends in coronal activity. Here we discuss the important He {\\sc i}-like ions and the differences in densities that result when different current data bases are used.

  6. High energy density redox flow device

    DOE Patents [OSTI]

    Chiang, Yet-Ming; Carter, W. Craig; Ho, Bryan Y; Duduta, Mihai; Limthongkul, Pimpa

    2014-05-13T23:59:59.000Z

    Redox flow devices are described in which at least one of the positive electrode or negative electrode-active materials is a semi-solid or is a condensed ion-storing electroactive material, and in which at least one of the electrode-active materials is transported to and from an assembly at which the electrochemical reaction occurs, producing electrical energy. The electronic conductivity of the semi-solid is increased by the addition of conductive particles to suspensions and/or via the surface modification of the solid in semi-solids (e.g., by coating the solid with a more electron conductive coating material to increase the power of the device). High energy density and high power redox flow devices are disclosed. The redox flow devices described herein can also include one or more inventive design features. In addition, inventive chemistries for use in redox flow devices are also described.

  7. SUPPRESSION OF DIELECTRONIC RECOMBINATION DUE TO FINITE DENSITY EFFECTS

    SciTech Connect (OSTI)

    Nikolic, D.; Gorczyca, T. W.; Korista, K. T. [Western Michigan University, Kalamazoo, MI (United States); Ferland, G. J. [University of Kentucky, Lexington, KY (United States); Badnell, N. R. [University of Strathclyde, Glasgow (United Kingdom)

    2013-05-01T23:59:59.000Z

    We have developed a general model for determining density-dependent effective dielectronic recombination (DR) rate coefficients in order to explore finite-density effects on the ionization balance of plasmas. Our model consists of multiplying by a suppression factor those highly-accurate total zero-density DR rate coefficients which have been produced from state-of-the-art theoretical calculations and which have been benchmarked by experiment. The suppression factor is based upon earlier detailed collision-radiative calculations which were made for a wide range of ions at various densities and temperatures, but used a simplified treatment of DR. A general suppression formula is then developed as a function of isoelectronic sequence, charge, density, and temperature. These density-dependent effective DR rate coefficients are then used in the plasma simulation code Cloudy to compute ionization balance curves for both collisionally ionized and photoionized plasmas at very low (n{sub e} = 1 cm{sup -3}) and finite (n{sub e} = 10{sup 10} cm{sup -3}) densities. We find that the denser case is significantly more ionized due to suppression of DR, warranting further studies of density effects on DR by detailed collisional-radiative calculations which utilize state-of-the-art partial DR rate coefficients. This is expected to impact the predictions of the ionization balance in denser cosmic gases such as those found in nova and supernova shells, accretion disks, and the broad emission line regions in active galactic nuclei.

  8. A nesting study of two populations of cardinals: urban and non-urban

    E-Print Network [OSTI]

    Kutac, Mary Florence

    1976-01-01T23:59:59.000Z

    ) compaxed bird populations for one year in the center of a city, a rural area and an uninhabited forest in Finland. Bird biomass was found to be 10 times higher in the city than in either of the other two settings. Population density was found to be 342...

  9. The Ultimate-Sustainable-Yield Problem in Nonlinear Age-Structured Populations*

    E-Print Network [OSTI]

    Getz, Wayne M.

    that it assumes that recruitment is independent of population density. *This work was partially supportedThe Ultimate-Sustainable-Yield Problem in Nonlinear Age-Structured Populations* WAYNE M. GETZ Africa Received 24 January 1979; revised IO Ju& 1979 ABSTRACT The Beverton-Holt theory of harvesting

  10. The effects of plant density upon pollination success, reproductive effort and fruit parasitism in Cistus ladanifer L. (Cistaceae)

    E-Print Network [OSTI]

    The effects of plant density upon pollination success, reproductive effort and fruit parasitism pollination success, reproductive effort and fruit parasitism in three populations of Cistus ladanifer L increased (pfruit parasitism showed the opposite pattern (both p

  11. Population and Climate Change:Population and Climate Change: Coupling Population Models withCoupling Population Models with

    E-Print Network [OSTI]

    Kalnay, Eugenia

    Coupling Population Models with Earth System ModelsEarth System Models Eugenia Kalnay, Safa Motesharrei, Jorge Rivas Change: Fully Coupling Population and Earth System Models" My research at the U. of Maryland #12

  12. OIL EXPOSURE AND CHRONIC HEALTH EFFECTS ON INDIGENOUS POPULATIONS IN SOUTH AMERICA.

    E-Print Network [OSTI]

    Gascon Merlos, M.

    2009-01-01T23:59:59.000Z

    ??There is an ongoing discussion on whether the activity of oil companies and its environmental impacts are a threat for the health of the populations (more)

  13. Intercrystalline density on nanocrystalline nickel

    SciTech Connect (OSTI)

    Haasz, T.R.; Aust, K.T. [Univ. of Toronto, Ontario (Canada). Dept. of Metallurgy and Materials Science] [Univ. of Toronto, Ontario (Canada). Dept. of Metallurgy and Materials Science; Palumbo, G. [Ontario Hydro Research Div., Toronto, Ontario (Canada)] [Ontario Hydro Research Div., Toronto, Ontario (Canada); El-Sherik, A.M.; Erb, U. [Queen`s Univ., Kingston, Ontario (Canada). Dept. of Materials and Metallurgical Engineering] [Queen`s Univ., Kingston, Ontario (Canada). Dept. of Materials and Metallurgical Engineering

    1995-02-01T23:59:59.000Z

    Most methods currently available for the synthesis of nanostructured materials result in considerable residual porosity. Studies concerned with the novel structures and properties of these materials are thus compromised by the intrinsically high levels of porosity. As recently shown by Kristic et al., porosity can have a significant effect on fundamental materials properties such as Young`s modulus. One of the most promising techniques for the production of fully dense nanocrystalline materials is electrodeposition. In the present work, the residual porosity and density of nanostructured nickel produced by the electrodeposition method is assessed and discussed in light of the intrinsic intercrystalline density of nickel.

  14. Time Dependent Density Functional Theory An introduction

    E-Print Network [OSTI]

    Botti, Silvana

    Time Dependent Density Functional Theory An introduction Francesco Sottile LSI, Ecole Polytechnique (ETSF) Time Dependent Density Functional Theory Palaiseau, 7 February 2012 1 / 32 #12;Outline 1 Frontiers 4 Perspectives and Resources Francesco Sottile (ETSF) Time Dependent Density Functional Theory

  15. Time Dependent Density Functional Theory An Introduction

    E-Print Network [OSTI]

    Botti, Silvana

    Time Dependent Density Functional Theory An Introduction Francesco Sottile Laboratoire des Solides) Belfast, 29 Jun 2007 Time Dependent Density Functional Theory Francesco Sottile #12;Intro Formalism Dependent Density Functional Theory Francesco Sottile #12;Intro Formalism Results Resources Outline 1

  16. Statistical density modification using local pattern matching

    DOE Patents [OSTI]

    Terwilliger, Thomas C.

    2007-01-23T23:59:59.000Z

    A computer implemented method modifies an experimental electron density map. A set of selected known experimental and model electron density maps is provided and standard templates of electron density are created from the selected experimental and model electron density maps by clustering and averaging values of electron density in a spherical region about each point in a grid that defines each selected known experimental and model electron density maps. Histograms are also created from the selected experimental and model electron density maps that relate the value of electron density at the center of each of the spherical regions to a correlation coefficient of a density surrounding each corresponding grid point in each one of the standard templates. The standard templates and the histograms are applied to grid points on the experimental electron density map to form new estimates of electron density at each grid point in the experimental electron density map.

  17. Open problems in nuclear density functional theory

    E-Print Network [OSTI]

    B. G. Giraud

    2009-11-30T23:59:59.000Z

    This note describes five subjects of some interest for the density functional theory in nuclear physics. These are, respectively, i) the need for concave functionals, ii) the nature of the Kohn-Sham potential for the radial density theory, iii) a proper implementation of a density functional for an "intrinsic" rotational density, iv) the possible existence of a potential driving the square root of the density, and v) the existence of many models where a density functional can be explicitly constructed.

  18. Density Functional Theory Study of Oxygen Reduction Activity on Ultrathin

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: Vegetation Proposed Newcatalyst phasesData Files DataADVANCES IN TIME-RESOLVEDPlatinum Nanotubes. |

  19. USING CUMULATIVE NUMBER DENSITIES TO COMPARE GALAXIES ACROSS COSMIC TIME

    SciTech Connect (OSTI)

    Behroozi, Peter S.; Wechsler, Risa H. [Kavli Institute for Particle Astrophysics and Cosmology, SLAC National Accelerator Laboratory, Stanford, CA 94305 (United States)] [Kavli Institute for Particle Astrophysics and Cosmology, SLAC National Accelerator Laboratory, Stanford, CA 94305 (United States); Marchesini, Danilo [Department of Physics and Astronomy, Tufts University, Medford, MA 02155 (United States)] [Department of Physics and Astronomy, Tufts University, Medford, MA 02155 (United States); Muzzin, Adam [Leiden Observatory, Leiden University, P.O. Box 9513, 2300 RA Leiden (Netherlands)] [Leiden Observatory, Leiden University, P.O. Box 9513, 2300 RA Leiden (Netherlands); Papovich, Casey [Department of Physics and Astronomy, Texas A and M University, College Station, TX 77843 (United States)] [Department of Physics and Astronomy, Texas A and M University, College Station, TX 77843 (United States); Stefanon, Mauro [Physics and Astronomy Department, University of Missouri, Columbia, MO 65211 (United States)] [Physics and Astronomy Department, University of Missouri, Columbia, MO 65211 (United States)

    2013-11-01T23:59:59.000Z

    Comparing galaxies across redshifts at fixed cumulative number density is a popular way to estimate the evolution of specific galaxy populations. This method ignores scatter in mass accretion histories and galaxy-galaxy mergers, which can lead to errors when comparing galaxies over large redshift ranges (?z > 1). We use abundance matching in the ?CDM paradigm to estimate the median change in cumulative number density with redshift and provide a simple fit (+0.16 dex per unit ?z) for progenitors of z = 0 galaxies. We find that galaxy descendants do not evolve in the same way as galaxy progenitors, largely due to scatter in mass accretion histories. We also provide estimates for the 1? range of cumulative number densities corresponding to galaxy progenitors and descendants. Finally, we discuss some limits on cumulative number density comparisons, which arise due to difficulties measuring physical quantities (e.g., stellar mass) consistently across redshifts. A public tool to calculate cumulative number density evolution for galaxies, as well as approximate halo masses, is available online.

  20. Transformations for densities Linear transformations

    E-Print Network [OSTI]

    Adler, Robert J.

    ' & $ % Lecture 28 Transformations for densities Linear transformations 1-1 differentiable functions General transformations Expectation of a function 1 #12;' & $ % Transformations for discrete transformation of a U[0, 1] · Take X U[0, 1], so that fX(x) = 1 0 0 and set Y

  1. The effects of low environmental cadmium exposure on bone density

    SciTech Connect (OSTI)

    Trzcinka-Ochocka, M., E-mail: ochocka@imp.lodz.pl [Department of Chemical Hazards, Laboratory of Biomonitoring, Nofer Institute of Occupational Medicine, Lodz (Poland); Jakubowski, M. [Department of Chemical Hazards, Laboratory of Biomonitoring, Nofer Institute of Occupational Medicine, Lodz (Poland)] [Department of Chemical Hazards, Laboratory of Biomonitoring, Nofer Institute of Occupational Medicine, Lodz (Poland); Szymczak, W. [Department of Environmental Epidemiology, Nofer Institute of Occupational Medicine, Lodz (Poland) [Department of Environmental Epidemiology, Nofer Institute of Occupational Medicine, Lodz (Poland); Insitute of Psychology, University of Lodz (Poland); Janasik, B.; Brodzka, R. [Department of Chemical Hazards, Laboratory of Biomonitoring, Nofer Institute of Occupational Medicine, Lodz (Poland)] [Department of Chemical Hazards, Laboratory of Biomonitoring, Nofer Institute of Occupational Medicine, Lodz (Poland)

    2010-04-15T23:59:59.000Z

    Recent epidemiological data indicate that low environmental exposure to cadmium, as shown by cadmium body burden (Cd-U), is associated with renal dysfunction as well as an increased risk of cadmium-induced bone disorders. The present study was designed to assess the effects of low environmental cadmium exposure, at the level sufficient to induce kidney damage, on bone metabolism and mineral density (BMD). The project was conducted in the area contaminated with cadmium, nearby a zinc smelter located in the region of Poland where heavy industry prevails. The study population comprised 170 women (mean age=39.7; 18-70 years) and 100 men (mean age=31.9; 18-76 years). Urinary and blood cadmium and the markers of renal tubular dysfunction ({beta}{sub 2}M-U RBP, NAG), glomerular dysfunction (Alb-U and {beta}{sub 2}M-S) and bone metabolism markers (BAP-S, CTX-S) as well as forearm BMD, were measured. The results of this study based on simple dose-effect analysis showed the relationship between increasing cadmium concentrations and an increased excretion of renal dysfunction markers and decreasing bone density. However, the results of the multivariate analysis did not indicate the association between exposure to cadmium and decrease in bone density. They showed that the most important factors that have impact on bone density are body weight and age in the female subjects and body weight and calcium excretion in males. Our investigation revealed that the excretion of low molecular weight proteins occurred at a lower level of cadmium exposure than the possible loss of bone mass. It seems that renal tubular markers are the most sensitive and significant indicators of early health effects of cadmium intoxication in the general population. The correlation of urinary cadmium concentration with markers of kidney dysfunction was observed in the absence of significant correlations with bone effects. Our findings did not indicate any effects of environmental cadmium exposure on bone density.

  2. ICF & High Energy Density (HED) Research Future Directions and Plans

    E-Print Network [OSTI]

    and ICF activities Energy Balance FY08 Getting the Job Done First credible ignition attempt FYNSP 20 YearsICF & High Energy Density (HED) Research Future Directions and Plans Fusion Power Associates of Defense Science and Inertial Fusion National Nuclear Security Administration US Dept. of Energy #12

  3. SECPOP90: Sector population, land fraction, and economic estimation program

    SciTech Connect (OSTI)

    Humphreys, S.L.; Rollstin, J.A.; Ridgely, J.N.

    1997-09-01T23:59:59.000Z

    In 1973 Mr. W. Athey of the Environmental Protection Agency wrote a computer program called SECPOP which calculated population estimates. Since that time, two things have changed which suggested the need for updating the original program - more recent population censuses and the widespread use of personal computers (PCs). The revised computer program uses the 1990 and 1992 Population Census information and runs on current PCs as {open_quotes}SECPOP90.{close_quotes} SECPOP90 consists of two parts: site and regional. The site provides population and economic data estimates for any location within the continental United States. Siting analysis is relatively fast running. The regional portion assesses site availability for different siting policy decisions; i.e., the impact of available sites given specific population density criteria within the continental United States. Regional analysis is slow. This report compares the SECPOP90 population estimates and the nuclear power reactor licensee-provided information. Although the source, and therefore the accuracy, of the licensee information is unknown, this comparison suggests SECPOP90 makes reasonable estimates. Given the total uncertainty in any current calculation of severe accidents, including the potential offsite consequences, the uncertainty within SECPOP90 population estimates is expected to be insignificant. 12 refs., 55 figs., 7 tabs.

  4. The M31 population of supersoft sources

    E-Print Network [OSTI]

    Peter Kahabka

    1999-01-12T23:59:59.000Z

    The 1991 ROSAT PSPC M31 X-ray point source catalog has been screened in order to set up a sample of candidate supersoft sources in this galaxy, additional to the 16 supersoft sources of Supper et al. (1997). 26 candidates have been found. Absorbing hydrogen column densities, effective temperatures and white dwarf masses (assuming the sources are on the stability line of surface nuclear burning) are derived. An observed white dwarf mass distribution is derived which indicates that the masses are constrained to values above 0.90 solar masses. The entire population of supersoft sources in M31 is estimated taking a theoretical white dwarf mass distribution into account, assuming that the observationally derived sample is restricted to white dwarf masses above 0.90 solar, and taking into account that the gas and the source population have a different scale height. A total number of at least 200-500 and at most 6,000-15,000 sources is deduced depending on the used galaxy N_H model, making use of the population synthesis calculation of Yungelson (1996). The spatial distribution favors a disk (or spiral-arm) dominated young stellar population with a ratio of 1/(4-7) of bulge/disk systems. Assuming that all supersoft sources with masses in excess of 0.5 solar masses are progenitors of supernovae of type Ia, a SN Ia rate of (0.8-7) 10^-3 yr^-1 is derived for M31 based on these progenitors. Supersoft sources might account for 20-100% of the total SN Ia rate in a galaxy like M31.

  5. Radiation transport and density effects in non-equilibrium plasmas Vladimir I. Fisher*, Dimitri V. Fisher, Yitzhak Maron

    E-Print Network [OSTI]

    Radiation transport and density effects in non-equilibrium plasmas Vladimir I. Fisher*, Dimitri V populations and the radiation field in transient non-equilibrium plasmas. In this model, the plasma density to a self-consistent treatment of the radiative transfer. For non-Maxwellian plasmas, the atomic

  6. vol. 155, no. 2 the american naturalist february 2000 Energy, Density, and Constraints to Species Richness: Ant

    E-Print Network [OSTI]

    Kaspari, Mike

    . This supports the energy limitation hypothesis' assumption that average population densities are highervol. 155, no. 2 the american naturalist february 2000 Energy, Density, and Constraints to Species in a given time and space. The energy limitation hy- pothesis links the species richness of consumer taxa

  7. Jacek Dobaczewski Density functional theory and energy

    E-Print Network [OSTI]

    Dobaczewski, Jacek

    Jacek Dobaczewski Density functional theory and energy density functionals in nuclear physics Jacek Functional #12;Jacek Dobaczewski Mean-Field Theory Density Functional Theory · mean-field one? Density Functional Theory: A variational method that uses observables as variational parameters. #12;Jacek

  8. Density Functional Theory (DFT) Rob Parrish

    E-Print Network [OSTI]

    Sherrill, David

    Density Functional Theory (DFT) Rob Parrish robparrish@gmail.com 1 #12;Agenda · The mechanism Easy to do this Why? Because of Hermitian Operators: Kinetic Energy Density: #12;Density Functional The density completely defines the observable state of the system: The way in which it does so (the functional

  9. A current density distribution tool

    E-Print Network [OSTI]

    Jagush, Frederic A.

    1989-01-01T23:59:59.000Z

    . I. INTRODUCTION Current density distribution is an important consideration for those involved in electrochemical systems and electroplating in particular. In the printed wiring board (PWB) business, great emphasis is placed on the study of current... exist. Numerical techniques on the other hand, are usually easy to implement and are easily applicable to microcomputers. Their disadvantage as with any approximation technique is that the exactness of the results with This document follows the style...

  10. Degenerate resistive switching and ultrahigh density storage in resistive memory

    SciTech Connect (OSTI)

    Lohn, Andrew J., E-mail: drewlohn@gmail.com; Mickel, Patrick R., E-mail: prmicke@sandia.gov; James, Conrad D.; Marinella, Matthew J. [Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States)

    2014-09-08T23:59:59.000Z

    We show that in tantalum oxide resistive memories, activation power provides a multi-level variable for information storage that can be set and read separately from the resistance. These two state variables (resistance and activation power) can be precisely controlled in two steps: (1) the possible activation power states are selected by partially reducing resistance, then (2) a subsequent partial increase in resistance specifies the resistance state and the final activation power state. We show that these states can be precisely written and read electrically, making this approach potentially amenable for ultra-high density memories. We provide a theoretical explanation for information storage and retrieval from activation power and experimentally demonstrate information storage in a third dimension related to the change in activation power with resistance.

  11. Probability distribution of the vacuum energy density

    SciTech Connect (OSTI)

    Duplancic, Goran; Stefancic, Hrvoje [Theoretical Physics Division, Rudjer Boskovic Institute, P.O. Box 180, HR-10002 Zagreb (Croatia); Glavan, Drazen [Department of Physics, Faculty of Science, University of Zagreb, P.O. Box 331, HR-10002 Zagreb (Croatia)

    2010-12-15T23:59:59.000Z

    As the vacuum state of a quantum field is not an eigenstate of the Hamiltonian density, the vacuum energy density can be represented as a random variable. We present an analytical calculation of the probability distribution of the vacuum energy density for real and complex massless scalar fields in Minkowski space. The obtained probability distributions are broad and the vacuum expectation value of the Hamiltonian density is not fully representative of the vacuum energy density.

  12. Mechanical reaction-diffusion model for bacterial population dynamics

    E-Print Network [OSTI]

    Ngamsaad, Waipot

    2015-01-01T23:59:59.000Z

    The effect of mechanical interaction between cells on the spreading of bacterial population was investigated in one-dimensional space. A nonlinear reaction-diffusion equation has been formulated as a model for this dynamics. In this model, the bacterial cells are treated as the rod-like particles that interact, when contacting each other, through the hard-core repulsion. The repulsion introduces the exclusion process that causes the fast diffusion in bacterial population at high density. The propagation of the bacterial density as the traveling wave front in long time behavior has been analyzed. The analytical result reveals that the front speed is enhanced by the exclusion process---and its value depends on the packing fraction of cell. The numerical solutions of the model have been solved to confirm this prediction.

  13. THE DENSITY PROFILES OF MASSIVE, RELAXED GALAXY CLUSTERS. II. SEPARATING LUMINOUS AND DARK MATTER IN CLUSTER CORES

    SciTech Connect (OSTI)

    Newman, Andrew B.; Ellis, Richard S. [Cahill Center for Astronomy and Astrophysics, California Institute of Technology, MS 249-17, Pasadena, CA 91125 (United States)] [Cahill Center for Astronomy and Astrophysics, California Institute of Technology, MS 249-17, Pasadena, CA 91125 (United States); Treu, Tommaso; Sand, David J., E-mail: anewman@astro.caltech.edu [Department of Physics, University of California, Santa Barbara, CA 93106 (United States)

    2013-03-01T23:59:59.000Z

    We present stellar and dark matter (DM) density profiles for a sample of seven massive, relaxed galaxy clusters derived from strong and weak gravitational lensing and resolved stellar kinematic observations within the centrally located brightest cluster galaxies (BCGs). In Paper I of the series, we demonstrated that the total density profile derived from these data, which span three decades in radius, is consistent with numerical DM-only simulations at radii {approx}> 5-10 kpc, despite the significant contribution of stellar material in the core. Here, we decompose the inner mass profiles of these clusters into stellar and dark components. Parameterizing the DM density profile as a power law {rho}{sub DM}{proportional_to}r {sup -{beta}} on small scales, we find a mean slope ({beta}) = 0.50 {+-} 0.10(random){sup +0.14} {sub -0.13}(systematic). Alternatively, cored Navarro-Frenk-White (NFW) profiles with (log r {sub core}/kpc) = 1.14 {+-} 0.13{sup +0.14} {sub -0.22} provide an equally good description. These density profiles are significantly shallower than canonical NFW models at radii {approx}< 30 kpc, comparable to the effective radii of the BCGs. The inner DM profile is correlated with the distribution of stars in the BCG, suggesting a connection between the inner halo and the assembly of stars in the central galaxy. The stellar mass-to-light ratio inferred from lensing and stellar dynamics is consistent with that inferred using stellar population synthesis models if a Salpeter initial mass function is adopted. We compare these results to theories describing the interaction between baryons and DM in cluster cores, including adiabatic contraction models and the possible effects of galaxy mergers and active galactic nucleus feedback, and evaluate possible signatures of alternative DM candidates.

  14. Influence of the Target - Density Effects on Electron - Capture Processes

    SciTech Connect (OSTI)

    Tolstikhina, I.Yu.; Shevelko, V.P. [P.N.Lebedev Physical Institute, 119991, Moscow (Russian Federation)

    2004-12-01T23:59:59.000Z

    The influence of the target density on the electron-capture (EC) processes in collisions of fast ions with atoms and molecules is considered. The partial EC cross sections {sigma}n on the principal quantum number n of the scattered projectile, as well as the total {sigma}tot values are calculated for highly charged ions interacting with gaseous and solid targets in the energy range of E = 100 keV/amu to 10 MeV/amu. It is shown that with the target density increasing, the population of the excited states of the scattered projectiles, formed via the EC channel, is suppressed due to projectile ionization by the target particles and, as a result, the effective EC cross sections drastically decrease.

  15. High density electronic circuit and process for making

    DOE Patents [OSTI]

    Morgan, William P. (Albuquerque, NM)

    1999-01-01T23:59:59.000Z

    High density circuits with posts that protrude beyond one surface of a substrate to provide easy mounting of devices such as integrated circuits. The posts also provide stress relief to accommodate differential thermal expansion. The process allows high interconnect density with fewer alignment restrictions and less wasted circuit area than previous processes. The resulting substrates can be test platforms for die testing and for multi-chip module substrate testing. The test platform can contain active components and emulate realistic operational conditions, replacing shorts/opens net testing.

  16. High density electronic circuit and process for making

    DOE Patents [OSTI]

    Morgan, W.P.

    1999-06-29T23:59:59.000Z

    High density circuits with posts that protrude beyond one surface of a substrate to provide easy mounting of devices such as integrated circuits are disclosed. The posts also provide stress relief to accommodate differential thermal expansion. The process allows high interconnect density with fewer alignment restrictions and less wasted circuit area than previous processes. The resulting substrates can be test platforms for die testing and for multi-chip module substrate testing. The test platform can contain active components and emulate realistic operational conditions, replacing shorts/opens net testing. 8 figs.

  17. Density functional theory of electrowetting

    E-Print Network [OSTI]

    Markus Bier; Ingrid Ibagon

    2014-02-10T23:59:59.000Z

    The phenomenon of electrowetting, i.e., the dependence of the macroscopic contact angle of a fluid on the electrostatic potential of the substrate, is analyzed in terms of the density functional theory of wetting. It is shown that electrowetting is not an electrocapillarity effect, i.e., it cannot be consistently understood in terms of the variation of the substrate-fluid interfacial tension with the electrostatic substrate potential, but it is related to the depth of the effective interface potential. The key feature, which has been overlooked so far and which occurs naturally in the density functional approach is the structural change of a fluid if it is brought into contact with another fluid. These structural changes occur in the present context as the formation of finite films of one fluid phase in between the substrate and the bulk of the other fluid phase. The non-vanishing Donnan potentials (Galvani potential differences) across such film-bulk fluid interfaces, which generically occur due to an unequal partitioning of ions as a result of differences of solubility contrasts, lead to correction terms in the electrowetting equation, which become relevant for sufficiently small substrate potentials. Whereas the present density functional approach confirms the commonly used electrocapillarity-based electrowetting equation as a good approximation for the cases of metallic electrodes or electrodes coated with a hydrophobic dielectric in contact with an electrolyte solution and an ion-free oil, a significantly reduced tendency for electrowetting is predicted for electrodes coated with a dielectric which is hydrophilic or which is in contact with two immiscible electrolyte solutions.

  18. POPULATION GEOGRAPHY Instructor: Dr. Carr

    E-Print Network [OSTI]

    Lopez-Carr, David

    in a year · Crude rates may be misleading: - e.g., CDR, US (8) vs. Mexico (5) -What's going on here? -Are: #12;HOW DOES POPULATION CHANGE? #12;Population Change = Fertility ­ Mortality +/- Migration #12;Crude Birth Rate (CBR): Births/1000 individuals in a year Crude Death Rate (CDR): Deaths/1000 individuals

  19. Perturbation Theory for Population Dynamics

    E-Print Network [OSTI]

    Francisco M. Fernandez

    2007-12-20T23:59:59.000Z

    We prove that a recently proposed homotopy perturbation method for the treatment of population dynamics is just the Taylor expansion of the population variables about initial time. Our results show that this perturbation method fails to provide the global features of the ecosystem dynamics.

  20. Affine maps of density matrices

    E-Print Network [OSTI]

    Thomas F. Jordan

    2004-11-21T23:59:59.000Z

    For quantum systems described by finite matrices, linear and affine maps of matrices are shown to provide equivalent descriptions of evolution of density matrices for a subsystem caused by unitary Hamiltonian evolution in a larger system; an affine map can be replaced by a linear map, and a linear map can be replaced by an affine map. There may be significant advantage in using an affine map. The linear map is generally not completely positive, but the linear part of an equivalent affine map can be chosen to be completely positive and related in the simplest possible way to the unitary Hamiltonian evolution in the larger system.

  1. Energy demand and population changes

    SciTech Connect (OSTI)

    Allen, E.L.; Edmonds, J.A.

    1980-12-01T23:59:59.000Z

    Since World War II, US energy demand has grown more rapidly than population, so that per capita consumption of energy was about 60% higher in 1978 than in 1947. Population growth and the expansion of per capita real incomes have led to a greater use of energy. The aging of the US population is expected to increase per capita energy consumption, despite the increase in the proportion of persons over 65, who consume less energy than employed persons. The sharp decline in the population under 18 has led to an expansion in the relative proportion of population in the prime-labor-force age groups. Employed persons are heavy users of energy. The growth of the work force and GNP is largely attributable to the growing participation of females. Another important consequence of female employment is the growth in ownership of personal automobiles. A third factor pushing up labor-force growth is the steady influx of illegal aliens.

  2. The Formation of Population III Binaries

    E-Print Network [OSTI]

    Kazuya Saigo; Tomoaki Matsumoto; Masayuki Umemura

    2004-10-29T23:59:59.000Z

    We explore the possibility for the formation of Population III binaries. The collapse of a rotating cylinder is simulated with a three-dimensional, high-resolution nested grid, assuming the thermal history of primordial gas. The simulations are done with dimensionless units, and the results are applicable to low-mass as well as massive systems by scaling with the initial density. We find that if the initial angular momentum is as small as $\\beta \\approx 0.1$, where $\\beta$ is the ratio of centrifugal force to pressure force, then the runaway collapse of the cloud stops to form a rotationally-supported disk. After the accretion of the envelope, the disk undergoes a ring instability, eventually fragmenting into a binary. If the initial angular momentum is relatively large, a bar-type instability arises, resulting in the collapse into a single star through rapid angular momentum transfer. The present results show that a significant fraction of Pop III stars are expected to form in binary systems, even if they are quite massive or less massive. The cosmological implications of Population III binaries are briefly discussed.

  3. Combining Density Functional Theory and Density Matrix Functional Theory Daniel R. Rohr1

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Combining Density Functional Theory and Density Matrix Functional Theory Daniel R. Rohr1 , Julien and CNRS, 4 place Jussieu, 75252 Paris, France We combine density-functional theory with density cleavage is an ubiquitous process for chemistry. Density-matrix functional theory (DMFT) (see, e.g., Refs

  4. Intraspecific variation in the strength of density dependence in aphid populations

    E-Print Network [OSTI]

    Underwood, Nora

    varies both within and between studies (Strong, 1984; Bjornstad et al., 1995; Cappuccino & Price, 1995

  5. High density behaviour of nuclear symmetry energy

    E-Print Network [OSTI]

    D. N. Basu; Tapan Mukhopadhyay

    2006-12-27T23:59:59.000Z

    Role of the isospin asymmetry in nuclei and neutron stars, with an emphasis on the density dependence of the nuclear symmetry energy, is discussed. The symmetry energy is obtained using the isoscalar as well as isovector components of the density dependent M3Y effective interaction. The constants of density dependence of the effective interaction are obtained by reproducing the saturation energy per nucleon and the saturation density of spin and isospin symmetric cold infinite nuclear matter. Implications for the density dependence of the symmetry energy in case of a neutron star are discussed, and also possible constraints on the density dependence obtained from finite nuclei are compared.

  6. Risk Bounds for Mixture Density Estimation

    E-Print Network [OSTI]

    Rakhlin, Alexander

    2004-01-27T23:59:59.000Z

    In this paper we focus on the problem of estimating a bounded density using a finite combination of densities from a given class. We consider the Maximum Likelihood Procedure (MLE) and the greedy procedure described by ...

  7. Quantum critical benchmark for density functional theory

    E-Print Network [OSTI]

    Paul E. Grabowski; Kieron Burke

    2014-08-09T23:59:59.000Z

    Two electrons at the threshold of ionization represent a severe test case for electronic structure theory. A pseudospectral method yields a very accurate density of the two-electron ion with nuclear charge close to the critical value. Highly accurate energy components and potentials of Kohn-Sham density functional theory are given, as well as a useful parametrization of the critical density. The challenges for density functional approximations and the strength of correlation are also discussed.

  8. Oxides having high energy densities

    DOE Patents [OSTI]

    Ceder, Gerbrand; Kang, Kisuk

    2013-09-10T23:59:59.000Z

    Certain disclosed embodiments generally relate to oxide materials having relatively high energy and/or power densities. Various aspects of the embodiments are directed to oxide materials having a structure B.sub.i(M.sub.jY.sub.k)O.sub.2, for example, a structure Li.sub.j(Ni.sub.jY.sub.k)O.sub.2 such as Li(Ni.sub.0.5Mn.sub.0.5)O.sub.2. In this structure, Y represents one or more atoms, each independently selected from the group consisting of alkaline earth metals, transition metals, Group 14 elements, Group 15, or Group 16 elements. In some embodiments, such an oxide material may have an O3 crystal structure, and/or a layered structure such that the oxide comprises a plurality of first, repeating atomic planes comprising Li, and a plurality of second, repeating atomic planes comprising Ni and/or Y.

  9. The Critical Density and the Effective Excitation Density of Commonly Observed Molecular Dense Gas Tracers

    E-Print Network [OSTI]

    Shirley, Yancy L

    2015-01-01T23:59:59.000Z

    The optically thin critical densities and the effective excitation densities to produce a 1 K km/s (or 0.818 Jy km/s $(\\frac{\

  10. Density Functional Theory Models for Radiation Damage

    E-Print Network [OSTI]

    Density Functional Theory Models for Radiation Damage S.L. Dudarev EURATOM/CCFE Fusion Association, DFT Abstract Density functional theory models developed over the past decade provide unique phenomena. Density functional theory models have effectively created a new paradigm for the scientific

  11. Time Dependent Density Functional Theory An introduction

    E-Print Network [OSTI]

    Botti, Silvana

    Time Dependent Density Functional Theory An introduction Francesco Sottile LSI, Ecole Polytechnique) Time Dependent Density Functional Theory Palaiseau, 26 May 2014 1 / 62 #12;Outline 1 Introduction: why and Resources Francesco Sottile (ETSF) Time Dependent Density Functional Theory Palaiseau, 26 May 2014 2 / 62

  12. DENSITY FUNCTIONAL THEORY OF FIELD THEORETICAL SYSTEMS

    E-Print Network [OSTI]

    Engel, Eberhard

    DENSITY FUNCTIONAL THEORY OF FIELD THEORETICAL SYSTEMS E. Engel Inst. fur Theor. Physik background of relativistic density functional theory is emphasized and its consequences for relativistic Kohn-Sham equations are shown. The local density approximation for the exchange energy functional is reviewed

  13. Density functional theory George F. Bertsch

    E-Print Network [OSTI]

    Bertsch George F.

    Density functional theory George F. Bertsch #3; Institute for Nuclear Theory and Department of Physics University of Tsukuba Tsukuba 305-8577 Japan Abstract Density functional theory is a remarkably Time-dependent density functional theory: the equations 34 A Optical properties

  14. DENSITY FUNCTIONAL THEORY, THE MODERN TREATMENT OF

    E-Print Network [OSTI]

    Gross, E.K.U.

    DENSITY FUNCTIONAL THEORY, THE MODERN TREATMENT OF ELECTRON CORRELATIONS E.K.U. Gross and Stefan The basic idea of density functional theory is to describe a many-electron system exclusively and completely-consistent scheme, known as the Kohn-Sham scheme [2], is the heart of modern density functional theory

  15. The influence of increasing population size and vegetation productivity on elephant distribution in the Kruger National Park

    E-Print Network [OSTI]

    Pretoria, University of

    -cell occupancy increased with population size, while grid-cell-specific density became less variable. In additionThe influence of increasing population size and vegetation productivity on elephant distribution Research Unit, Department of Zoology and Entomology, University of Pretoria, Pretoria 0002, South Africa

  16. Energy Systems and Population Health

    SciTech Connect (OSTI)

    Ezzati, Majid; Bailis, Rob; Kammen, Daniel M.; Holloway, Tracey; Price, Lynn; Cifuentes, Luis A.; Barnes, Brendon; Chaurey, Akanksha; Dhanapala, Kiran N.

    2004-04-12T23:59:59.000Z

    It is well-documented that energy and energy systems have a central role in social and economic development and human welfare at all scales, from household and community to regional and national (41). Among its various welfare effects, energy is closely linked with people s health. Some of the effects of energy on health and welfare are direct. With abundant energy, more food or more frequent meals can be prepared; food can be refrigerated, increasing the types of food items that are consumed and reducing food contamination; water pumps can provide more water and eliminate the need for water storage leading to contamination or increased exposure to disease vectors such as mosquitoes or snails; water can be disinfected by boiling or using other technologies such as radiation. Other effects of energy on public health are mediated through more proximal determinants of health and disease. Abundant energy can lead to increased irrigation, agricultural productivity, and access to food and nutrition; access to energy can also increase small-scale income generation such as processing of agricultural commodities (e.g., producing refined oil from oil seeds, roasting coffee, drying and preserving fruits and meats) and production of crafts; ability to control lighting and heating allows education or economic activities to be shielded from daily or seasonal environmental constraints such as light, temperature, rainfall, or wind; time and other economic resources spent on collecting and/or transporting fuels can be used for other household needs if access to energy is facilitated; energy availability for transportation increases access to health and education facilities and allow increased economic activity by facilitating the transportation of goods and services to and from markets; energy for telecommunication technology (radio, television, telephone, or internet) provides increased access to information useful for health, education, or economic purposes; provision of energy to rural and urban health facilities allows increased delivery and coverage of 3 various health services and interventions such as tests and treatments, better storage of medicine and vaccines, disinfection of medical equipment by boiling or radiation, and more frequent and efficient health system encounters through mobile clinics or longer working hours; and so on. In fact, while the dominant view of development-energy-health linkages has been that improvements in energy and health are outcomes of the socioeconomic development process (e.g., the ''energy ladder'' framework discussed below), it has even been argued that access to higher quality energy sources and technologies can initiate a chain of demographic, health, and development outcomes by changing the household structure and socioeconomic relationships. For example, in addition to increased opportunities for food and income production, reduced infant mortality as a result of transition to cleaner fuels or increased coverage of vaccination with availability of refrigerators in rural clinics may initiate a process of ''demographic transition'' to low-mortality and low-fertility populations (14). Such a transition has historically been followed with further improvements in maternal and child health and increased female participation in the labor markets and other economic activities.

  17. Gas Density and the Volume Schmidt Law for Spiral Galaxies

    E-Print Network [OSTI]

    O. V. Abramova; A. V. Zasov

    2007-10-01T23:59:59.000Z

    The thickness of the equilibrium isothermal gaseous layers and their volume densities \\rho_{gas}(R) in the disc midplane are calculated for 7 spiral galaxies (including our Galaxy) in the frame of self-consistent axisymmetric model. Local velocity dispersions of stellar discs were assumed to be close to marginal values necessary for the discs to be in a stable equilibrium state. Under this condition the stellar discs of at least 5 of 7 galaxies reveal a flaring. Their volume densities decrease with R faster than \\rho_{gas}, and, as a result, the gas dominates by the density at the disc periphery. Comparison of the azimuthally averaged star formation rate SFR with the gas density shows that there is no universal Schmidt law SFR \\rho_{gas}^n, common to all galaxies. Nevertheless, SFR in different galaxies reveals better correlation with the volume gas density than with the column one. Parameter n in the Schmidt law SFR \\rho_{gas}^n, formally calculated by the least square method, lies within 0.8-2.4 range and it's mean value is close to 1.5. Values of n calculated for molecular gas only are characterized by large dispersion, but their mean value is close to 1. Hence the smaller \\rho_{gas} the less is a fraction of gas actively taking part in the process of star formation.

  18. Risk assessment for osteoporotic fractures among men and women from a prospective population study: the EPIC-Norfolk study

    E-Print Network [OSTI]

    Moayyeri, Alireza

    2012-03-06T23:59:59.000Z

    ................................................................................................ 99 6.4. Results ................................................................................................ 101 6.4.1. Characteristics of the study population ....................................... 101 6.4.2. Physical activity and heel...

  19. Aerodynamic Focusing Of High-Density Aerosols

    SciTech Connect (OSTI)

    Ruiz, D. E.; Fisch, Nathaniel

    2014-02-24T23:59:59.000Z

    High-density micron-sized particle aerosols might form the basis for a number of applications in which a material target with a particular shape might be quickly ionized to form a cylindrical or sheet shaped plasma. A simple experimental device was built in order to study the properties of high-density aerosol focusing for 1#22; m silica spheres. Preliminary results recover previous findings on aerodynamic focusing at low densities. At higher densities, it is demonstrated that the focusing properties change in a way which is consistent with a density dependent Stokes number.

  20. Multiscale modeling of oscillations and spiral waves in Dictyostelium populations

    E-Print Network [OSTI]

    Javad Noorbakhsh; David Schwab; Allyson Sgro; Thomas Gregor; Pankaj Mehta

    2014-09-12T23:59:59.000Z

    Unicellular organisms exhibit elaborate collective behaviors in response to environmental cues. These behaviors are controlled by complex biochemical networks within individual cells and coordinated through cell-to-cell communication. Describing these behaviors requires new mathematical models that can bridge scales -- from biochemical networks within individual cells to spatially structured cellular populations. Here, we present a family of multiscale models for the emergence of spiral waves in the social amoeba Dictyostelium discoideum. Our models exploit new experimental advances that allow for the direct measurement and manipulation of the small signaling molecule cAMP used by Dictyostelium cells to coordinate behavior in cellular populations. Inspired by recent experiments, we model the Dictyostelium signaling network as an excitable system coupled to various pre-processing modules. We use this family of models to study spatially unstructured populations by constructing phase diagrams that relate the properties of population-level oscillations to parameters in the underlying biochemical network. We then extend our models to include spatial structure and show how they naturally give rise to spiral waves. Our models exhibit a wide range of novel phenomena including a density dependent frequency change, bistability, and dynamic death due to slow cAMP dynamics. Our modeling approach provides a powerful tool for bridging scales in modeling of Dictyostelium populations.

  1. active populations based: Topics by E-print Network

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

    behaviors, such as chemical diffusiondetection, motility, proliferation, adhesion and life cycle stages. In this paper we extend the model to simulate heterotypic cell sorting....

  2. Proceedings: Workshop on Compensatory Mechanisms in Fish Populations

    SciTech Connect (OSTI)

    None

    1982-12-01T23:59:59.000Z

    This report contains a summary of an EPRI workshop on compensatory mechanisms in fish populations, held in February 1982 in Palo Alto, California. The participants recommended two broad conceptual frameworks for the development of a research program and identified major research activities. These plans were later integrated into a final research program, which is included here.

  3. KH Computational Physics-2009 Density Functional Theory (DFT) Density Functional Theory

    E-Print Network [OSTI]

    Haule, Kristjan

    KH Computational Physics- 2009 Density Functional Theory (DFT) Density Functional Theory of interacting particles. Kristjan Haule, 2009 ­2­ #12;KH Computational Physics- 2009 Density Functional Theory functional of n. Kristjan Haule, 2009 ­3­ #12;KH Computational Physics- 2009 Density Functional Theory (DFT

  4. Density-functional theory of nonuniform classical liquids: An extended modified weighted-density approximation

    E-Print Network [OSTI]

    Likos, Christos N.

    Density-functional theory of nonuniform classical liquids: An extended modified weighted-density the approximationstreat long-rangeand short-rangepotentials. I. INTRODUCTION The density-functional theory of nonuniform of density- functional theory to the problem of freezing of classical liquids,4 and in particular

  5. Dot Density Maps Dot density maps, or dot maps, portray the geographic distribution of discrete phenomena

    E-Print Network [OSTI]

    Klippel, Alexander

    Dot Density Maps Dot density maps, or dot maps, portray the geographic distribution of discrete for representing geographic patterns. Dot density maps are particularly useful for understanding global distribution of the mapped phenomenon and comparing relative densities of different regions on the map. Dot

  6. Quartz resonator fluid density and viscosity monitor

    DOE Patents [OSTI]

    Martin, Stephen J. (Albuquerque, NM); Wiczer, James J. (Albuquerque, NM); Cernosek, Richard W. (Albuquerque, NM); Frye, Gregory C. (Cedar Crest, NM); Gebert, Charles T. (Albuquerque, NM); Casaus, Leonard (Bernalillo, NM); Mitchell, Mary A. (Tijeras, NM)

    1998-01-01T23:59:59.000Z

    A pair of thickness-shear mode resonators, one smooth and one with a textured surface, allows fluid density and viscosity to be independently resolved. A textured surface, either randomly rough or regularly patterned, leads to trapping of liquid at the device surface. The synchronous motion of this trapped liquid with the oscillating device surface allows the device to weigh the liquid; this leads to an additional response that depends on liquid density. This additional response enables a pair of devices, one smooth and one textured, to independently resolve liquid density and viscosity; the difference in responses determines the density while the smooth device determines the density-viscosity product, and thus, the pair determines both density and viscosity.

  7. Theory for planetary exospheres: II. Radiation pressure effect on exospheric density profiles

    E-Print Network [OSTI]

    Beth, Arnaud; Toublanc, Dominique; Dandouras, Iannis; Mazelle, Christian

    2015-01-01T23:59:59.000Z

    The planetary exospheres are poorly known in their outer parts, since the neutral densities are low compared with the instruments detection capabilities. The exospheric models are thus often the main source of information at such high altitudes. We present a new way to take into account analytically the additional effect of the radiation pressure on planetary exospheres. In a series of papers, we present with an Hamiltonian approach the effect of the radiation pressure on dynamical trajectories, density profiles and escaping thermal flux. Our work is a generalization of the study by Bishop and Chamberlain (1989). In this second part of our work, we present here the density profiles of atomic Hydrogen in planetary exospheres subject to the radiation pressure. We first provide the altitude profiles of ballistic particles (the dominant exospheric population in most cases), which exhibit strong asymmetries that explain the known geotail phenomenon at Earth. The radiation pressure strongly enhances the densities c...

  8. Cardiovascular disease, diabetes and established risk factors among populations of sub-Saharan African descent in Europe: a literature review

    E-Print Network [OSTI]

    Agyemang, Charles; Addo, Juliet; Bhopal, Raj; de-Graft Aikins, Ama; Stronks, Karien

    2009-08-11T23:59:59.000Z

    . Dutch African-Suriname men and women are less physically active than the White-Dutch whereas British African women are more physically active than women in the general population. Literature on psychosocial stress shows inconsistent results. Conclusion...

  9. The Effect of Environmental Contaminants on Mating Dynamics and Population Viability in a Sex-Role-Reversed Pipefish

    E-Print Network [OSTI]

    Partridge, Charlyn G.

    2010-07-14T23:59:59.000Z

    Understanding how anthropogenic activity impacts the health and viability of wildlife populations is one of the most important tasks of environmental biology. A key concern related to bi-products of human activity is the accumulation...

  10. Considering Air Density in Wind Power Production

    E-Print Network [OSTI]

    Farkas, Zn

    2011-01-01T23:59:59.000Z

    In the wind power production calculations the air density is usually considered as constant in time. Using the CIPM-2007 equation for the density of moist air as a function of air temperature, air pressure and relative humidity, we show that it is worth taking the variation of the air density into account, because higher accuracy can be obtained in the calculation of the power production for little effort.

  11. Considering Air Density in Wind Power Production

    E-Print Network [OSTI]

    Zn Farkas

    2011-03-11T23:59:59.000Z

    In the wind power production calculations the air density is usually considered as constant in time. Using the CIPM-2007 equation for the density of moist air as a function of air temperature, air pressure and relative humidity, we show that it is worth taking the variation of the air density into account, because higher accuracy can be obtained in the calculation of the power production for little effort.

  12. Method of synthesizing a low density material

    DOE Patents [OSTI]

    Lorensen, L.E.; Monaco, S.B.

    1987-02-27T23:59:59.000Z

    A novel method of synthesizing a polymeric material of low density of the order of 50mg/cc or less. Such a low density material has applications in many areas including laser target fabrication. The method comprises preparing a polymer blend of two incompatible polymers as a major and a minor phase by mixing them and extruding the mixture, and then selectively extracting the major component, to yield a fine, low density structure.

  13. The blue plume population in dwarf spheroidal galaxies: genuine blue stragglers or young stellar population?

    E-Print Network [OSTI]

    Y. Momany; E. V. Held; I. Saviane; S. Zaggia; L. Rizzi; M. Gullieuszik

    2007-04-11T23:59:59.000Z

    Abridged... Blue stragglers (BSS) are thought to be the product of either primordial or collisional binary systems. In the context of dwarf spheroidal galaxies it is hard to firmly disentangle a genuine BSS population from young main sequence (MS) stars tracing a ~1-2 Gyr old star forming episode. Assuming that their blue plume populations are made of BSS, we estimate the BSS frequency for 8 Local Group non star-forming dwarf galaxies, using a compilation of ground and space based photometry. Our results can be summarized as follows: (i) The BSS frequency in dwarf galaxies, at any given Mv, is always higher than that in globular clusters of similar luminosities; (ii) the BSS frequency for the lowest luminosity dwarf galaxies is in excellent agreement with that observed in the Milky Way halo; and most interestingly (iii) derive a statistically significant anti-correlation between the BSS frequency and the galaxy Mv. The low density, almost collision-less, environments of our dwarf galaxy sample allow us to infer (i) their very low dynamical evolution; (ii) a negligible production of collisional BSS; and consequently (iii) that their blue plumes are mainly made of primordial binaries. The dwarf galaxies anti-correlation can be used as a discriminator: galaxies obeying the anti-correlation are more likely to possess genuine primordial BSS rather than young main sequence stars.

  14. Betatron radiation from density tailored plasmas

    E-Print Network [OSTI]

    Ta Phuoc, Kim

    2010-01-01T23:59:59.000Z

    Betatron radiation from density tailored plasmas K. Tathe resulting betatron radiation spectrum can therefore bepro?le, the betatron radiation emitted by theses electrons

  15. Some challenges for Nuclear Density Functional Theory

    E-Print Network [OSTI]

    T. Duguet; K. Bennaceur; T. Lesinski; J. Meyer

    2006-06-20T23:59:59.000Z

    We discuss some of the challenges that the DFT community faces in its quest for the truly universal energy density functional applicable over the entire nuclear chart.

  16. 3-D capacitance density imaging system

    DOE Patents [OSTI]

    Fasching, G.E.

    1988-03-18T23:59:59.000Z

    A three-dimensional capacitance density imaging of a gasified bed or the like in a containment vessel is achieved using a plurality of electrodes provided circumferentially about the bed in levels and along the bed in channels. The electrodes are individually and selectively excited electrically at each level to produce a plurality of current flux field patterns generated in the bed at each level. The current flux field patterns are suitably sensed and a density pattern of the bed at each level determined. By combining the determined density patterns at each level, a three-dimensional density image of the bed is achieved. 7 figs.

  17. Mon. Not. R. Astron. Soc. 000, ???? (2012) Printed 3 May 2013 (MN LATEX style file v2.2) Herschel -ATLAS/GAMA: The Environmental Density of

    E-Print Network [OSTI]

    Baes, Maarten

    the normalized environmental densities of these two populations. This is such that infrared emission (a tracer -ATLAS/GAMA: The Environmental Density of Far-Infrared Bright Galaxies at z 0.5 C. S. Burton1 , Matt J1 3RH, UK 3Physics Department, University of the Western Cape, Bellville 7535, South Africa 4School

  18. aerial density profiles: Topics by E-print Network

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

    present an analytic approach to predict gas density and temperature profiles in dark matter haloes. We assume that the gas density profile traces the dark matter density profile...

  19. The MSW conversion of solar neutrinos and random matter density perturbations

    E-Print Network [OSTI]

    H. Nunokawa; A. Rossi; V. B. Semikoz; J. W. F. Valle

    1996-10-29T23:59:59.000Z

    We present a generalization of the resonant neutrino conversion in matter, including a random component in the matter density profile. The study is focused on the effect of such matter perturbations upon both large and small mixing angle MSW solutions to the solar neutrino problem. This is carried out both for the active-active $\

  20. The stellar population of bulges

    E-Print Network [OSTI]

    P. Jablonka

    2007-01-07T23:59:59.000Z

    This review summarizes the properties of the stellar population in bulges as observed in nearby or distant spiral galaxies. It gives a particular emphasis to the comparison with elliptical galaxies, when possible. The criteria of sample selection and choices in data analysis are addressed when they may be involved in discrepant results reached by different studies.

  1. Population and Climate Change:Population and Climate Change: Coupling Population Models withCoupling Population Models with

    E-Print Network [OSTI]

    Kalnay, Eugenia

    carbon over the next 40 years as adopting low-carbon technologies Concluded: Family planning is cost / Capita Outputs: 1. Emissions CO2, Methane, etc 2. Waste Products Garbage, Toxics, etc 3. Surface Changes are needed to: · Stabilize population and · Stabilize industrial production per person · Adopt technologies

  2. Population Displacements Associated with Environmentally

    E-Print Network [OSTI]

    Columbia University

    Socio economic Impacts Enviro Impacts Dam Climate Change Fresh H20 Salinization Drought Flood infrastructure Climate Impact(s) Infrastructure development objectives Socio economic Impacts Enviro Impacts ­ Environmental impacts of major infrastructure projects 2 P l i di l i d i h l i f2. Population displacements

  3. Population Ecology ISSN 1438-3896

    E-Print Network [OSTI]

    de Aguiar, Marcus A. M.

    1 23 Population Ecology ISSN 1438-3896 Popul Ecol DOI 10.1007/s10144-012-0352-3 Impacts of enemy of Population Ecology and Springer Japan. This e-offprint is for personal use only and shall not be self of Population Ecology and Springer Japan 2012 Abstract In this study, we used data from both experi- ments

  4. Shrinking Global Population: A futuristic scenario

    E-Print Network [OSTI]

    Nagurney, Anna

    global population it will not be a game-changer. #12;Measures for changes in total births 1. TotalShrinking Global Population: A futuristic scenario or a current challenge. Hillel Bar of RSAI - Atlanta November 15, 2013 #12;The evolution of global population Year Global Population

  5. The 2dF Galaxy Redshift Survey: luminosity functions by density environment and galaxy type

    E-Print Network [OSTI]

    Darren J. Croton; Glennys R. Farrar; Peder Norberg; Matthew Colless; John A. Peacock; I. K. Baldry; C. M. Baugh; J. Bland-Hawthorn; T. Bridges; R. Cannon; S. Cole; C. Collins; W. Couch; G. Dalton; R. De Propris; S. P. Driver; G. Efstathiou; R. S. Ellis; C. S. Frenk; K. Glazebrook; C. Jackson; O. Lahav; I. Lewis; S. Lumsden; S. Maddox; D. Madgwick; B. A. Peterson; W. Sutherland; K. Taylor

    2005-02-08T23:59:59.000Z

    We use the 2dF Galaxy Redshift Survey to measure the dependence of the bJ-band galaxy luminosity function on large-scale environment, defined by density contrast in spheres of radius 8h-1Mpc, and on spectral type, determined from principal component analysis. We find that the galaxy populations at both extremes of density differ significantly from that at the mean density. The population in voids is dominated by late types and shows, relative to the mean, a deficit of galaxies that becomes increasingly pronounced at magnitudes brighter than M_bJ-5log10h <-18.5. In contrast, cluster regions have a relative excess of very bright early-type galaxies with M_bJ-5log10h < -21. Differences in the mid to faint-end population between environments are significant: at M_bJ-5log10h=-18 early and late-type cluster galaxies show comparable abundances, whereas in voids the late types dominate by almost an order of magnitude. We find that the luminosity functions measured in all density environments, from voids to clusters, can be approximated by Schechter functions with parameters that vary smoothly with local density, but in a fashion which differs strikingly for early and late-type galaxies. These observed variations, combined with our finding that the faint-end slope of the overall luminosity function depends at most weakly on density environment, may prove to be a significant challenge for models of galaxy formation.

  6. EO 12898: Environmental Justice in Minority Populations and Low...

    Office of Environmental Management (EM)

    EO 12898: Environmental Justice in Minority Populations and Low-Income Populations EO 12898: Environmental Justice in Minority Populations and Low-Income Populations To focus...

  7. The Formation of Population III Binaries

    E-Print Network [OSTI]

    Saigo, K; Umemura, M; Saigo, Kazuya; Matsumoto, Tomoaki; Umemura, Masayuki

    2004-01-01T23:59:59.000Z

    We explore the possibility for the formation of Population III binaries. The collapse of a rotating cylinder is simulated with a three-dimensional, high-resolution nested grid, assuming the thermal history of primordial gas. The simulations are done with dimensionless units, and the results are applicable to low-mass as well as massive systems by scaling with the initial density. We find that if the initial angular momentum is as small as $\\beta \\approx 0.1$, where $\\beta$ is the ratio of centrifugal force to pressure force, then the runaway collapse of the cloud stops to form a rotationally-supported disk. After the accretion of the envelope, the disk undergoes a ring instability, eventually fragmenting into a binary. If the initial angular momentum is relatively large, a bar-type instability arises, resulting in the collapse into a single star through rapid angular momentum transfer. The present results show that a significant fraction of Pop III stars are expected to form in binary systems, even if they ar...

  8. A Unifying Theory for Scaling Laws of Human Populations

    E-Print Network [OSTI]

    Lin, Henry W

    2015-01-01T23:59:59.000Z

    The spatial distribution of people exhibits clustering across a wide range of scales, from household (~$10^{-2}$ km) to continental (~$10^4$ km) scales. Empirical data indicates simple power-law scalings for the size distribution of cities (known as Zipf's law), the geographic distribution of friends, and the population density fluctuations as a function of scale. We derive a simple statistical model that explains all of these scaling laws based on a single unifying principle involving the random spatial growth of clusters of people on all scales. The model makes important new predictions for the spread of diseases and other social phenomena.

  9. High density laser-driven target

    DOE Patents [OSTI]

    Lindl, John D. (San Ramon, CA)

    1981-01-01T23:59:59.000Z

    A high density target for implosion by laser energy composed of a central quantity of fuel surrounded by a high-Z pusher shell with a low-Z ablator-pusher shell spaced therefrom forming a region filled with low-density material.

  10. Density Estimation Trees in High Energy Physics

    E-Print Network [OSTI]

    Anderlini, Lucio

    2015-01-01T23:59:59.000Z

    Density Estimation Trees can play an important role in exploratory data analysis for multidimensional, multi-modal data models of large samples. I briefly discuss the algorithm, a self-optimization technique based on kernel density estimation, and some applications in High Energy Physics.

  11. Brain covariance selection: better individual functional connectivity models using population prior

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Brain covariance selection: better individual functional connectivity models using population prior bertrand.thirion@inria.fr Abstract Spontaneous brain activity, as observed in functional neuroimaging, has been shown to display reproducible structure that expresses brain architecture and car- ries markers

  12. Theoretical Population Biology 53, 216 235 (1998) Evolutionary Stable Strategies and Trade-Offs

    E-Print Network [OSTI]

    Getz, Wayne M.

    Theoretical Population Biology 53, 216 235 (1998) Evolutionary Stable Strategies and Trade Mathematics, University of the Orange Free State, P.O. Box 339, Bloemfontein 9300, South Africa and Wayne M in which a parameter # characterizes the onset of density dependence. An evolutionary stable strategy

  13. Theoretical Population Biology 71 (2007) 111 Nonlinear dynamics and pattern bifurcations in a model for vegetation

    E-Print Network [OSTI]

    Sherratt, Jonathan A.

    Theoretical Population Biology 71 (2007) 1­11 Nonlinear dynamics and pattern bifurcations observed in aerial photographs of sub- Saharan Africa in the 1950s (MacFadyen, 1950; Hemming, 1965; Wickens in the plant density U because the presence of plant roots in the soil increases water ARTICLE IN PRESS www

  14. Density of Spray-Formed Materials

    SciTech Connect (OSTI)

    Kevin M. McHugh; Volker Uhlenwinkel; Nils Ellendr

    2008-06-01T23:59:59.000Z

    Spray Forming is an advanced materials processing technology that transforms molten metal into a near-net-shape solid by depositing atomized droplets onto a substrate. Depending on the application, the spray-formed material may be used in the as-deposited condition or it may undergo post-deposition processing. Regardless, the density of the as-deposited material is an important issue. Porosity is detrimental because it can significantly reduce strength, toughness, hardness and other properties. While it is not feasible to achieve fully-dense material in the as-deposited state, density greater than 99% of theoretical density is possible if the atomization and impact conditions are optimized. Thermal conditions at the deposit surface and droplet impact angle are key processing parameters that influence the density of the material. This paper examines the factors that contribute to porosity formation during spray forming and illustrates that very high as-deposited density is achieved by optimizing processing parameters.

  15. Density functional theory for carbon dioxide crystal

    SciTech Connect (OSTI)

    Chang, Yiwen; Mi, Jianguo, E-mail: mijg@mail.buct.edu.cn; Zhong, Chongli [State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029 (China)

    2014-05-28T23:59:59.000Z

    We present a density functional approach to describe the solid?liquid phase transition, interfacial and crystal structure, and properties of polyatomic CO{sub 2}. Unlike previous phase field crystal model or density functional theory, which are derived from the second order direct correlation function, the present density functional approach is based on the fundamental measure theory for hard-sphere repulsion in solid. More importantly, the contributions of enthalpic interactions due to the dispersive attractions and of entropic interactions arising from the molecular architecture are integrated in the density functional model. Using the theoretical model, the predicted liquid and solid densities of CO{sub 2} at equilibrium triple point are in good agreement with the experimental values. Based on the structure of crystal-liquid interfaces in different planes, the corresponding interfacial tensions are predicted. Their respective accuracies need to be tested.

  16. Neutral depletion and the helicon density limit

    SciTech Connect (OSTI)

    Magee, R. M.; Galante, M. E.; Carr, J. Jr.; Lusk, G.; McCarren, D. W.; Scime, E. E. [West Virginia University, Morgantown, West Virginia 26506 (United States)] [West Virginia University, Morgantown, West Virginia 26506 (United States)

    2013-12-15T23:59:59.000Z

    It is straightforward to create fully ionized plasmas with modest rf power in a helicon. It is difficult, however, to create plasmas with density >10{sup 20} m{sup ?3}, because neutral depletion leads to a lack of fuel. In order to address this density limit, we present fast (1 MHz), time-resolved measurements of the neutral density at and downstream from the rf antenna in krypton helicon plasmas. At the start of the discharge, the neutral density underneath the antenna is reduced to 1% of its initial value in 15 ?s. The ionization rate inferred from these data implies that the electron temperature near the antenna is much higher than the electron temperature measured downstream. Neutral density measurements made downstream from the antenna show much slower depletion, requiring 14 ms to decrease by a factor of 1/e. Furthermore, the downstream depletion appears to be due to neutral pumping rather than ionization.

  17. How to Calculate Molecular Column Density

    E-Print Network [OSTI]

    Mangum, Jeffrey G

    2015-01-01T23:59:59.000Z

    The calculation of the molecular column density from molecular spectral (rotational or ro-vibrational) transition measurements is one of the most basic quantities derived from molecular spectroscopy. Starting from first principles where we describe the basic physics behind the radiative and collisional excitation of molecules and the radiative transfer of their emission, we derive a general expression for the molecular column density. As the calculation of the molecular column density involves a knowledge of the molecular energy level degeneracies, rotational partition functions, dipole moment matrix elements, and line strengths, we include generalized derivations of these molecule-specific quantities. Given that approximations to the column density equation are often useful, we explore the optically thin, optically thick, and low-frequency limits to our derived general molecular column density relation. We also evaluate the limitations of the common assumption that the molecular excitation temperature is con...

  18. Ions in solution: Density corrected density functional theory (DC-DFT)

    SciTech Connect (OSTI)

    Kim, Min-Cheol; Sim, Eunji, E-mail: esim@yonsei.ac.kr [Department of Chemistry and Institute of Nano-Bio Molecular Assemblies, Yonsei University, 50 Yonsei-ro Seodaemun-gu, Seoul 120-749 (Korea, Republic of)] [Department of Chemistry and Institute of Nano-Bio Molecular Assemblies, Yonsei University, 50 Yonsei-ro Seodaemun-gu, Seoul 120-749 (Korea, Republic of); Burke, Kieron [Department of Chemistry, University of California, Irvine, California 92697 (United States)] [Department of Chemistry, University of California, Irvine, California 92697 (United States)

    2014-05-14T23:59:59.000Z

    Standard density functional approximations often give questionable results for odd-electron radical complexes, with the error typically attributed to self-interaction. In density corrected density functional theory (DC-DFT), certain classes of density functional theory calculations are significantly improved by using densities more accurate than the self-consistent densities. We discuss how to identify such cases, and how DC-DFT applies more generally. To illustrate, we calculate potential energy surfaces of HOCl{sup ?} and HOH{sub 2}O complexes using various common approximate functionals, with and without this density correction. Commonly used approximations yield wrongly shaped surfaces and/or incorrect minima when calculated self consistently, while yielding almost identical shapes and minima when density corrected. This improvement is retained even in the presence of implicit solvent.

  19. Wood density measurement protocol J Chave Page 1 Measuring wood density for tropical forest trees

    E-Print Network [OSTI]

    Chave, Jérôme

    Wood density measurement protocol ­ J Chave Page 1 Measuring wood density for tropical forest trees Diversité Biologique Université Paul Sabatier 31000 Toulouse, France 1. Introduction Wood is a biological, that transport the sap along the stem and they are filled by water. The density of tree wood is an interesting

  20. Testing the kinetic energy functional: Kinetic energy density as a density functional

    E-Print Network [OSTI]

    Burke, Kieron

    is to the exchange-correlation energy as a functional of the density. A large part of the total energy, the kinetic contexts. For finite systems these forms integrate to the same global ki- netic energy, but they differTesting the kinetic energy functional: Kinetic energy density as a density functional Eunji Sim

  1. Managing Natural and Reintroduced Rare Plant Populations within a Large Government Reservation

    SciTech Connect (OSTI)

    Carlsen, T M; Paterson, L E; Alfaro, T M

    2009-07-15T23:59:59.000Z

    California is home to many large government reservations that have been in existence for decades. Many of these reservations were formed to support various Department of Defense and Department of Energy national defense activities. Often, only a very small percentage of the reservation is actively used for programmatic activities, resulting in large areas of intact habitat. In some cases, this has benefited rare plant populations, as surrounding lands have been developed for residential or industrial use. However, land management activities such as the suppression or active use of fire and other disturbance (such as fire trail grading) can also work to either the detriment or benefit of rare plant populations at these sites. A management regime that is beneficial to the rare plant populations of interest and is at best consistent with existing site programmatic activities, and at a minimum does not impact such activities, has the best potential for a positive outcome. As a result, some species may be 'difficult' while others may be 'easy' to manage in this context, depending on how closely the species biological requirements match the programmatic activities on the reservation. To illustrate, we compare and contrast two rare annual plant species found at Lawrence Livermore National Laboratory's Site 300. Although several populations of Amsinckia grandiflora have been restored on the site, and all populations are intensively managed, this species continues to decline. In contrast, Blepharizonia plumosa appears to take advantage of the annual controlled burns conducted on the site, and is thriving.

  2. Galaxy ecology: groups and low-density environments in the SDSS and 2dFGRS

    E-Print Network [OSTI]

    Michael Balogh; Vince Eke; Chris Miller; Ian Lewis; Richard Bower; Warrick Couch; Robert Nichol; Joss Bland-Hawthorn; Ivan K. Baldry; Carlton Baugh; Terry Bridges; Russell Cannon; Shaun Cole; Matthew Colless; Chris Collins; Nicholas Cross; Gavin Dalton; Roberto De Propris; Simon P. Driver; George Efstathiou; Richard S. Ellis; Carlos S. Frenk; Karl Glazebrook; Percy Gomez; Alex Gray; Edward Hawkins; Carole Jackson; Ofer Lahav; Stuart Lumsden; Steve Maddox; Darren Madgwick; Peder Norberg; John A. Peacock; Will Percival; Bruce A. Peterson; Will Sutherland; Keith Taylor

    2004-01-05T23:59:59.000Z

    We analyse the observed correlation between galaxy environment and H-alpha emission line strength, using volume-limited samples and group catalogues of 24968 galaxies drawn from the 2dF Galaxy Redshift Survey (Mb<-19.5) and the Sloan Digital Sky Survey (Mr<-20.6). We characterise the environment by 1) Sigma_5, the surface number density of galaxies determined by the projected distance to the 5th nearest neighbour; and 2) rho1.1 and rho5.5, three-dimensional density estimates obtained by convolving the galaxy distribution with Gaussian kernels of dispersion 1.1 Mpc and 5.5 Mpc, respectively. We find that star-forming and quiescent galaxies form two distinct populations, as characterised by their H-alpha equivalent width, EW(Ha). The relative numbers of star-forming and quiescent galaxies varies strongly and continuously with local density. However, the distribution of EW(Ha) amongst the star-forming population is independent of environment. The fraction of star-forming galaxies shows strong sensitivity to the density on large scales, rho5.5, which is likely independent of the trend with local density, rho1.1. We use two differently-selected group catalogues to demonstrate that the correlation with galaxy density is approximately independent of group velocity dispersion, for sigma=200-1000 km/s. Even in the lowest density environments, no more than ~70 per cent of galaxies show significant H-alpha emission. Based on these results, we conclude that the present-day correlation between star formation rate and environment is a result of short-timescale mechanisms that take place preferentially at high redshift, such as starbursts induced by galaxy-galaxy interactions.

  3. Periodic subsystem density-functional theory

    SciTech Connect (OSTI)

    Genova, Alessandro; Pavanello, Michele, E-mail: m.pavanello@rutgers.edu [Department of Chemistry, Rutgers University, Newark, New Jersey 07102 (United States); Ceresoli, Davide [Department of Chemistry, Rutgers University, Newark, New Jersey 07102 (United States); CNR-ISTM, Institute of Molecular Sciences and Technologies, Milano (Italy)

    2014-11-07T23:59:59.000Z

    By partitioning the electron density into subsystem contributions, the Frozen Density Embedding (FDE) formulation of subsystem Density Functional Theory (DFT) has recently emerged as a powerful tool for reducing the computational scaling of KohnSham DFT. To date, however, FDE has been employed to molecular systems only. Periodic systems, such as metals, semiconductors, and other crystalline solids have been outside the applicability of FDE, mostly because of the lack of a periodic FDE implementation. To fill this gap, in this work we aim at extending FDE to treat subsystems of molecular and periodic character. This goal is achieved by a dual approach. On one side, the development of a theoretical framework for periodic subsystem DFT. On the other, the realization of the method into a parallel computer code. We find that periodic FDE is capable of reproducing total electron densities and (to a lesser extent) also interaction energies of molecular systems weakly interacting with metallic surfaces. In the pilot calculations considered, we find that FDE fails in those cases where there is appreciable density overlap between the subsystems. Conversely, we find FDE to be in semiquantitative agreement with KohnSham DFT when the inter-subsystem density overlap is low. We also conclude that to make FDE a suitable method for describing molecular adsorption at surfaces, kinetic energy density functionals that go beyond the GGA level must be employed.

  4. Density Prediction of Uranium-6 Niobium Ingots

    SciTech Connect (OSTI)

    D.F.Teter; P.K. Tubesing; D.J.Thoma; E.J.Peterson

    2003-04-15T23:59:59.000Z

    The densities of uranium-6 niobium (U-Nb) alloys have been compiled from a variety of literature sources such as Y-12 and Rocky Flats datasheets. We also took advantage of the 42 well-pedigreed, homogeneous baseline U-Nb alloys produced under the Enhanced Surveillance Program for density measurements. Even though U-Nb alloys undergo two-phase transitions as the Nb content varies from 0 wt. % to 8 wt %, the theoretical and measured densities vary linearly with Nb content. Therefore, the effect of Nb content on the density was modeled with a linear regression. From this linear regression, a homogeneous ingot of U-6 wt.% Nb would have a density of 17.382 {+-} 0.040 g/cc (95% CI). However, ingots produced at Y-12 are not homogeneous with respect to the Nb content. Therefore, using the 95% confidence intervals, the density of a Y-12 produced ingot would vary from 17.310 {+-} 0.043 g/cc at the center to 17.432 {+-} 0.039 g/cc at the edge. Ingots with larger Nb inhomogeneities will also have larger variances in the density.

  5. Density equalizing map projections (cartograms) in public health applications

    SciTech Connect (OSTI)

    Merrill, D.W.

    1998-05-01T23:59:59.000Z

    In studying geographic disease distributions, one normally compares rates among arbitrarily defined geographic subareas (e.g. census tracts), thereby sacrificing some of the geographic detail of the original data. The sparser the data, the larger the subareas must be in order to calculate stable rates. This dilemma is avoided with the technique of Density Equalizing Map Projections (DEMP){copyright}. Boundaries of geographic subregions are adjusted to equalize population density over the entire study area. Case locations plotted on the transformed map should have a uniform distribution if the underlying disease risk is constant. On the transformed map, the statistical analysis of the observed distribution is greatly simplified. Even for sparse distributions, the statistical significance of a supposed disease cluster can be calculated with validity. The DEMP algorithm was applied to a data set previously analyzed with conventional techniques; namely, 401 childhood cancer cases in four counties of California. The distribution of cases on the transformed map was analyzed visually and statistically. To check the validity of the method, the identical analysis was performed on 401 artificial cases randomly generated under the assumption of uniform risk. No statistically significant evidence for geographic non-uniformity of rates was found, in agreement with the original analysis performed by the California Department of Health Services.

  6. Cosmological Deuterium Abundance and the Baryon Density of the Universe

    E-Print Network [OSTI]

    Scott Burles; David Tytler

    1996-03-19T23:59:59.000Z

    Standard big bang nucleosynthesis (BBNS) promises accurate predictions of the primordial abundances of deuterium, helium-3, helium-4 and lithium-7 as a function of a single parameter. Previous measurements have nearly always been interpreted as confirmation of the model (Copi, Schramm & Turner 1995). Here we present a measurement of the deuterium to hydrogen ratio (D/H) in a newly discovered high redshift metal-poor gas cloud at redshift $z=2.504$. This confirms our earlier measurement of D/H (Tytler, Fan & Burles 1996), and together they give the first accurate measurement of the primordial D abundance, and a ten fold improvement in the accuracy of the cosmological density of ordinary matter.This is a high density, with most ordinary matter unaccounted or dark, which is too high to agree with measurements of the primordial abundances of helium-4 and lithium-7. Since the D/H measurement is apparently simple, direct, accurate and highly sensitive, we propose that helium requires a systematic correction, and that population II stars have less than the primordial abundance of $^7$Li. Alternatively, there is no concordance between the light element abundances, and the simple model of the big bang must be incomplete and lacking physics, or wrong.

  7. Low density, resorcinol-formaldehyde aerogels

    DOE Patents [OSTI]

    Pekala, R.W.

    1988-05-26T23:59:59.000Z

    The polycondensation of resorcinol with formaldehyde under alkaline conditions results in the formation of surface functionalized polymer ''clusters''. The covalent crosslinking of these ''clusters'' produces gels which when processed under supercritical conditions, produce low density, organic aerogels (density less than or equal to100 mg/cc; cell size less than or equal to0.1 microns). The aerogels are transparent,dark red in color and consist of interconnected colloidal-like particles with diameters of about 100 A/degree/. These aerogels may be further carbonized to form low density carbon foams with cell size of about 0.1 micron. 1 fig., 1 tab.

  8. Low density, resorcinol-formaldehyde aerogels

    DOE Patents [OSTI]

    Pekala, Richard W. (Pleasant Hill, CA)

    1991-01-01T23:59:59.000Z

    The polycondensation of resorcinol with formaldehyde under alkaline conditions results in the formation of surface functionalized polymer "Clusters". The covalent crosslinking of these "clusters" produces gels which when processed under supercritical conditions, produce low density, organic aerogels (density.ltoreq.100 mg/cc; cell size .ltoreq.0.1 microns). The aerogels are transparent, dark red in color and consist of interconnected colloidal-like particles with diameters of about 100.circle.. These aerogels may be further carbonized to form low density carbon foams with cell size of about 0.1 micron.

  9. Low density, resorcinol-formaldehyde aerogels

    SciTech Connect (OSTI)

    Pekala, Richard W. (Pleasant Hill, CA)

    1989-01-01T23:59:59.000Z

    The polycondensation of resorcinol with formaldehyde under alkaline conditions results in the formation of surface functionalized polymer "clusters". The covalent crosslinking of these "clusters" produces gels which when processed under supercritical conditions, produce low density, organic aerogels (density .ltoreq.100 mg/cc; cell size .ltoreq.0.1 microns). The aerogels are transparent, dark red in color and consist of interconnected colloidal-like particles with diameters of about 100 .ANG.. These aerogels may be further carbonized to form low density carbon foams with cell size of about 0.1 micron.

  10. Low density, resorcinol-formaldehyde aerogels

    DOE Patents [OSTI]

    Pekala, R.W.

    1989-10-10T23:59:59.000Z

    The polycondensation of resorcinol with formaldehyde under alkaline conditions results in the formation of surface functionalized polymer clusters. The covalent crosslinking of these clusters produces gels which when processed under supercritical conditions, produce low density, organic aerogels (density [<=]100 mg/cc; cell size [<=]0.1 microns). The aerogels are transparent, dark red in color and consist of interconnected colloidal-like particles with diameters of about 100 [angstrom]. These aerogels may be further carbonized to form low density carbon foams with cell size of about 0.1 micron.

  11. The temperature dependence of equilibrium plasma density

    E-Print Network [OSTI]

    B. V. Vasiliev

    2002-03-17T23:59:59.000Z

    Temperature dependence of an electron-nuclear plasma equilibrium density is considered basing on known approaches, which are given in (1)(2). It is shown that at a very high temperature, which is characteristic for a star interior, the equilibrium plasma density is almost constant and equals approximately to $10^{25}$ particles per $cm^3$. At a relatively low temperature, which is characteristic for star surface, the equilibrium plasma density is in several orders lower and depends on temperature as $T^{3/2}$.

  12. Instabilities in the Nuclear Energy Density Functional

    E-Print Network [OSTI]

    M. Kortelainen; T. Lesinski

    2010-02-05T23:59:59.000Z

    In the field of Energy Density Functionals (EDF) used in nuclear structure and dynamics, one of the unsolved issues is the stability of the functional. Numerical issues aside, some EDFs are unstable with respect to particular perturbations of the nuclear ground-state density. The aim of this contribution is to raise questions about the origin and nature of these instabilities, the techniques used to diagnose and prevent them, and the domain of density functions in which one should expect a nuclear EDF to be stable.

  13. Report of the Interagency Task Force on High Energy Density Physics

    SciTech Connect (OSTI)

    None

    2007-08-01T23:59:59.000Z

    Identifies the needs for improving Federal stewardship of specific aspects of high energy density physics, particularly the study of high energy density plasmas in the laboratory, and strengthening university activities in this latter discipline. The report articulates how HEDP fits into the portfolio of federally funded missions and includes agency actions to be taken that are necessary to further this area of study consistent with Federal priorities and plans, while being responsive to the needs of the scientific community.

  14. The Active Asteroids

    E-Print Network [OSTI]

    Jewitt, David; Agarwal, Jessica

    2015-01-01T23:59:59.000Z

    Some asteroids eject dust, producing transient, comet-like comae and tails; these are the active asteroids. The causes of activity in this newly-identified population are many and varied. They include impact ejection and disruption, rotational instabilities, electrostatic repulsion, radiation pressure sweeping, dehydration stresses and thermal fracture, in addition to the sublimation of asteroidal ice. These processes were either unsuspected or thought to lie beyond the realm of observation before the discovery of asteroid activity. Scientific interest in the active asteroids lies in their promise to open new avenues into the direct study of asteroid destruction, the production of interplanetary debris, the abundance of asteroid ice and the origin of terrestrial planet volatiles.

  15. Individual-based model of yellow perch and walleye populations in Oneida Lake

    SciTech Connect (OSTI)

    Rose, K.A. [Oak Ridge National Lab., TN (United States). Environmental Sciences Div.; Rutherford, E.S. [Univ. of Michigan, Ann Arbor, MI (United States). Inst. for Fisheries Research; McDermot, D.S. [Univ. of Tennessee, Knoxville, TN (United States). Dept. of Ecology and Evolutionary Biology; Forney, J.L.; Mills, E.L. [Cornell Univ. Biological Station, Bridgeport, NY (United States)

    1999-05-01T23:59:59.000Z

    Predator-prey dynamics and density dependence are fundamental issues in ecology. The authors use a detailed, individual-based model of walleye and yellow perch to investigate the effects of alternative prey and compensatory responses on predator and prey population dynamics. The analyses focus on the numerical and developmental responses of the predator, rather than the traditional emphasis on functional responses. The extensive database for Oneida Lake, New York, USA was used to configure the model and ensure its realism. The model follows the daily growth, mortality, and spawning of individuals of each species through their lifetime. Three ecologically distinct periods in the history of Oneida Lake were simulated: baseline, high mayfly densities, and high forage fish densities. Mayflies and forage fish act as alternative prey for walleye. For model corroboration, the three periods were simulated sequentially as they occurred in Oneida Lake. Model predictions of abundances, size at age, and growth and survival rates compared favorably with Oneida Lake data. Three hypotheses suggested by the data were evaluated: alternative prey stabilizes yellow perch and walleye populations; alternative prey increases yellow perch and walleye recruitment; and density-dependent growth and survival compensate for changes in young-of-the-year mortality. Model simulations were performed under increased mayfly densities, increased forage fish densities, and increased egg mortality rates.

  16. Shock compression of low-density foams

    SciTech Connect (OSTI)

    Holmes, N.C.

    1993-07-01T23:59:59.000Z

    Shock compression of very low density micro-cellular materials allows entirely new regimes of hot fluid states to be investigated experimentally. Using a two-stage light-gas gun to generate strong shocks, temperatures of several eV are readily achieved at densities of roughly 0.5--1 g/cm{sup 3} in large, uniform volumes. The conditions in these hot, expanded fluids are readily found using the Hugoniot jump conditions. We will briefly describe the basic methodology for sample preparation and experimental measurement of shock velocities. We present data for several materials over a range of initial densities. This paper will explore the applications of these methods for investigations of equations of state and phase diagrams, spectroscopy, and plasma physics. Finally, we discus the need for future work on these and related low-density materials.

  17. Breast Density and Cancer | GE Global Research

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

    Breast Cancer Awareness Series: Understanding Breast Density Click to email this to a friend (Opens in new window) Share on Facebook (Opens in new window) Click to share (Opens in...

  18. Magnetic fields and density functional theory

    SciTech Connect (OSTI)

    Salsbury Jr., Freddie

    1999-02-01T23:59:59.000Z

    A major focus of this dissertation is the development of functionals for the magnetic susceptibility and the chemical shielding within the context of magnetic field density functional theory (BDFT). These functionals depend on the electron density in the absence of the field, which is unlike any other treatment of these responses. There have been several advances made within this theory. The first of which is the development of local density functionals for chemical shieldings and magnetic susceptibilities. There are the first such functionals ever proposed. These parameters have been studied by constructing functionals for the current density and then using the Biot-Savart equations to obtain the responses. In order to examine the advantages and disadvantages of the local functionals, they were tested numerically on some small molecules.

  19. Density controlled carbon nanotube array electrodes

    DOE Patents [OSTI]

    Ren, Zhifeng F. (Newton, MA); Tu, Yi (Belmont, MA)

    2008-12-16T23:59:59.000Z

    CNT materials comprising aligned carbon nanotubes (CNTs) with pre-determined site densities, catalyst substrate materials for obtaining them and methods for forming aligned CNTs with controllable densities on such catalyst substrate materials are described. The fabrication of films comprising site-density controlled vertically aligned CNT arrays of the invention with variable field emission characteristics, whereby the field emission properties of the films are controlled by independently varying the length of CNTs in the aligned array within the film or by independently varying inter-tubule spacing of the CNTs within the array (site density) are disclosed. The fabrication of microelectrode arrays (MEAs) formed utilizing the carbon nanotube material of the invention is also described.

  20. Inverse diffusion from knowledge of power densities

    E-Print Network [OSTI]

    Bal, Guillaume; Monard, Francois; Triki, Faouzi

    2011-01-01T23:59:59.000Z

    This paper concerns the reconstruction of a diffusion coefficient in an elliptic equation from knowledge of several power densities. The power density is the product of the diffusion coefficient with the square of the modulus of the gradient of the elliptic solution. The derivation of such internal functionals comes from perturbing the medium of interest by acoustic (plane) waves, which results in small changes in the diffusion coefficient. After appropriate asymptotic expansions and (Fourier) transformation, this allow us to construct the power density of the equation point-wise inside the domain. Such a setting finds applications in ultrasound modulated electrical impedance tomography and ultrasound modulated optical tomography. We show that the diffusion coefficient can be uniquely and stably reconstructed from knowledge of a sufficient large number of power densities. Explicit expressions for the reconstruction of the diffusion coefficient are also provided. Such results hold for a large class of boundary...

  1. High density effective theory on the lattice

    E-Print Network [OSTI]

    A. Dougall

    2007-10-08T23:59:59.000Z

    Long-range interactions in finite density QCD necessitate a non-perturbative approach in order to reliably map out the key features and spectrum of the QCD phase diagram. However, the complex nature of the fermion determinant in this sector prohibits the use of established Monte Carlo techniques that utilize importance sampling. Whilst significant progress has been made in the low density, high temperature region, this remains a considerable challenge at mid to high density. At large chemical potential, QCD can be approximated using high density effective theory which is free from the sign problem at leading order. We investigate the implementation of this theory on the lattice in conjunction with existing re-weighting techniques.

  2. QCD Level Density from Maximum Entropy Method

    E-Print Network [OSTI]

    Shinji Ejiri; Tetsuo Hatsuda

    2005-09-24T23:59:59.000Z

    We propose a method to calculate the QCD level density directly from the thermodynamic quantities obtained by lattice QCD simulations with the use of the maximum entropy method (MEM). Understanding QCD thermodynamics from QCD spectral properties has its own importance. Also it has a close connection to phenomenological analyses of the lattice data as well as experimental data on the basis of hadronic resonances. Our feasibility study shows that the MEM can provide a useful tool to study QCD level density.

  3. Abstract-In this study, imaging of electrical current density in conducting objects, which contain nuclear magnetic resonance

    E-Print Network [OSTI]

    Eybolu, Murat

    nuclear magnetic resonance (NMR) active nuclei is planned using 0.15T Magnetic Resonance Imaging (MRI at each cycle within the object. The applied current pulse creates a measurable magnetic flux density. The component of magnetic flux density parallel to the main magnetic field accumulates an additional phase

  4. Arthropod population and community dynamics in turfgrass

    E-Print Network [OSTI]

    Wang, Yong

    1998-01-01T23:59:59.000Z

    Non-target arthropod and nematode populations in ographics. fungal and nematode treated bermudagrass were contrasted with populations in a chlorpyrifos and an untreated control treatment. Fifty-five arthropod families or suborder, herein referred...

  5. Stellar populations of bulges at low redshift

    E-Print Network [OSTI]

    Sanchez-Blazquez, Patricia

    2015-01-01T23:59:59.000Z

    This chapter summarizes our current understanding of the stellar population properties of bulges and outlines important future research directions.

  6. CENTER FOR PULSED POWER DRIVEN HIGH ENERGY DENSITY PLASMA STUDIES

    SciTech Connect (OSTI)

    Professor Bruce R. Kusse; Professor David A. Hammer

    2007-04-18T23:59:59.000Z

    This annual report summarizes the activities of the Cornell Center for Pulsed-Power-Driven High-Energy-Density Plasma Studies, for the 12-month period October 1, 2005-September 30, 2006. This period corresponds to the first year of the two-year extension (awarded in October, 2005) to the original 3-year NNSA/DOE Cooperative Agreement with Cornell, DE-FC03-02NA00057. As such, the period covered in this report also corresponds to the fourth year of the (now) 5-year term of the Cooperative Agreement. The participants, in addition to Cornell University, include Imperial College, London (IC), the University of Nevada, Reno (UNR), the University of Rochester (UR), the Weizmann Institute of Science (WSI), and the P.N. Lebedev Physical Institute (LPI), Moscow. A listing of all faculty, technical staff and students, both graduate and undergraduate, who participated in Center research activities during the year in question is given in Appendix A.

  7. Active, polymer-based composite material implementing simple shear

    E-Print Network [OSTI]

    Lee, Sang Jin

    2009-05-15T23:59:59.000Z

    A novel active material for controllable, high work density applications was designed, fabricated, analyzed, and tested. This active material uses a lens-shaped element to implement simple shear motion with gas pressure actuation. The lens element...

  8. Nuclear energy density optimization: Shell structure

    E-Print Network [OSTI]

    M. Kortelainen; J. McDonnell; W. Nazarewicz; E. Olsen; P. -G. Reinhard; J. Sarich; N. Schunck; S. M. Wild; D. Davesne; J. Erler; A. Pastore

    2014-04-28T23:59:59.000Z

    Nuclear density functional theory is the only microscopical theory that can be applied throughout the entire nuclear landscape. Its key ingredient is the energy density functional. In this work, we propose a new parameterization UNEDF2 of the Skyrme energy density functional. The functional optimization is carried out using the POUNDerS optimization algorithm within the framework of the Skyrme Hartree-Fock-Bogoliubov theory. Compared to the previous parameterization UNEDF1, restrictions on the tensor term of the energy density have been lifted, yielding a very general form of the energy density functional up to second order in derivatives of the one-body density matrix. In order to impose constraints on all the parameters of the functional, selected data on single-particle splittings in spherical doubly-magic nuclei have been included into the experimental dataset. The agreement with both bulk and spectroscopic nuclear properties achieved by the resulting UNEDF2 parameterization is comparable with UNEDF1. While there is a small improvement on single-particle spectra and binding energies of closed shell nuclei, the reproduction of fission barriers and fission isomer excitation energies has degraded. As compared to previous UNEDF parameterizations, the parameter confidence interval for UNEDF2 is narrower. In particular, our results overlap well with those obtained in previous systematic studies of the spin-orbit and tensor terms. UNEDF2 can be viewed as an all-around Skyrme EDF that performs reasonably well for both global nuclear properties and shell structure. However, after adding new data aiming to better constrain the nuclear functional, its quality has improved only marginally. These results suggest that the standard Skyrme energy density has reached its limits and significant changes to the form of the functional are needed.

  9. The HI content of early-type galaxies from the ALFALFA survey. II. The case of low density environments

    E-Print Network [OSTI]

    Grossi, M; Giovanardi, C; Gavazzi, G; Giovanelli, R; Haynes, M P; Kent, B R; Pellegrini, S; Stierwalt, S; Trinchieri, G

    2009-01-01T23:59:59.000Z

    We present the analysis of the HI content of a sample of early-type galaxies (ETGs) in low-density environments (LDEs) using the data set provided by the Arecibo Legacy Fast ALFA (ALFALFA) survey. We compare their properties to the sample in the Virgo cluster that we studied in a previous paper (di Serego Alighieri et al. 2007, Paper I). We have selected a sample of 62 nearby ETGs (V -17). In both cases it is 10 times higher than that of the Virgo cluster. The presence of gas can be related to a recent star formation activity: 60% of all ETGs with HI have optical emission line ratios typical of star-forming galaxies and blue colours suggesting the presence of young stellar populations, especially in the dwarf subsample. We show that the HI detection rate of ETGs depends both on the environment and mass. The fraction of early-type systems with neutral hy drogen is higher in more massive objects when compared to early-type dwarfs. The ETGs in LDEs seem to have more heterogeneous properties than their Virgo clus...

  10. A Bayesian Probability Calculus for Density Matrices

    E-Print Network [OSTI]

    Manfred K. Warmuth; Dima Kuzmin

    2014-08-09T23:59:59.000Z

    One of the main concepts in quantum physics is a density matrix, which is a symmetric positive definite matrix of trace one. Finite probability distributions are a special case where the density matrix is restricted to be diagonal. Density matrices are mixtures of dyads, where a dyad has the form uu' for any any unit column vector u. These unit vectors are the elementary events of the generalized probability space. Perhaps the simplest case to see that something unusual is going on is the case of uniform density matrix, i.e. 1/n times identity. This matrix assigns probability 1/n to every unit vector, but of course there are infinitely many of them. The new normalization rule thus says that sum of probabilities over any orthonormal basis of directions is one. We develop a probability calculus based on these more general distributions that includes definitions of joints, conditionals and formulas that relate these, i.e. analogs of the theorem of total probability, various Bayes rules for the calculation of posterior density matrices, etc. The resulting calculus parallels the familiar 'classical' probability calculus and always retains the latter as a special case when all matrices are diagonal. Whereas the classical Bayesian methods maintain uncertainty about which model is 'best', the generalization maintains uncertainty about which unit direction has the largest variance. Surprisingly the bounds also generalize: as in the classical setting we bound the negative log likelihood of the data by the negative log likelihood of the MAP estimator.

  11. Orbital-optimized density cumulant functional theory

    SciTech Connect (OSTI)

    Sokolov, Alexander Yu., E-mail: asokolov@uga.edu; Schaefer, Henry F. [Center for Computational Quantum Chemistry, University of Georgia, Athens, Georgia 30602 (United States)] [Center for Computational Quantum Chemistry, University of Georgia, Athens, Georgia 30602 (United States)

    2013-11-28T23:59:59.000Z

    In density cumulant functional theory (DCFT) the electronic energy is evaluated from the one-particle density matrix and two-particle density cumulant, circumventing the computation of the wavefunction. To achieve this, the one-particle density matrix is decomposed exactly into the mean-field (idempotent) and correlation components. While the latter can be entirely derived from the density cumulant, the former must be obtained by choosing a specific set of orbitals. In the original DCFT formulation [W. Kutzelnigg, J. Chem. Phys. 125, 171101 (2006)] the orbitals were determined by diagonalizing the effective Fock operator, which introduces partial orbital relaxation. Here we present a new orbital-optimized formulation of DCFT where the energy is variationally minimized with respect to orbital rotations. This introduces important energy contributions and significantly improves the description of the dynamic correlation. In addition, it greatly simplifies the computation of analytic gradients, for which expressions are also presented. We offer a perturbative analysis of the new orbital stationarity conditions and benchmark their performance for a variety of chemical systems.

  12. ORBITAL-FREE KINETIC-ENERGY DENSITY FUNCTIONAL THEORY

    E-Print Network [OSTI]

    Wang, Yan Alexander

    Chapter 5 ORBITAL-FREE KINETIC-ENERGY DENSITY FUNCTIONAL THEORY Yan Alexander Wang and Emily A Theory (DFT), there was the Thomas-Fermi (TF) model, which uses the electron density ¢¡ r£ (a function-dependent DFT Density-Functional Theory DI density-independent DM1 first-order reduced density matrix EDF energy

  13. Population Biology Graduate Group Bylaws of the Population Biology Graduate Group

    E-Print Network [OSTI]

    Wainwright, Peter C.

    Population Biology Graduate Group Bylaws of the Population Biology Graduate Group Amended and Approved: February 1, 1994 I. Definition of the Graduate Group in Population Biology The purpose of this graduate group is to bring together faculty and graduate students interested in population biology

  14. High power density solid oxide fuel cells

    DOE Patents [OSTI]

    Pham, Ai Quoc; Glass, Robert S.

    2004-10-12T23:59:59.000Z

    A method for producing ultra-high power density solid oxide fuel cells (SOFCs). The method involves the formation of a multilayer structure cells wherein a buffer layer of doped-ceria is deposited intermediate a zirconia electrolyte and a cobalt iron based electrode using a colloidal spray deposition (CSD) technique. For example, a cobalt iron based cathode composed of (La,Sr)(Co,Fe)O (LSCF) may be deposited on a zirconia electrolyte via a buffer layer of doped-ceria deposited by the CSD technique. The thus formed SOFC have a power density of 1400 mW/cm.sup.2 at 600.degree. C. and 900 mW/cm.sup.2 at 700.degree. C. which constitutes a 2-3 times increased in power density over conventionally produced SOFCs.

  15. Statistical approach to nuclear level density

    SciTech Connect (OSTI)

    Sen'kov, R. A.; Horoi, M. [Department of Physics, Central Michigan University, Mount Pleasant, MI 48859 (United States); Zelevinsky, V. G. [Department of Physics and Astronomy and National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, MI 48824-1321 (United States)

    2014-10-15T23:59:59.000Z

    We discuss the level density in a finite many-body system with strong interaction between the constituents. Our primary object of applications is the atomic nucleus but the same techniques can be applied to other mesoscopic systems. We calculate and compare nuclear level densities for given quantum numbers obtained by different methods, such as nuclear shell model (the most successful microscopic approach), our main instrument - moments method (statistical approach), and Fermi-gas model; the calculation with the moments method can use any shell-model Hamiltonian excluding the spurious states of the center-of-mass motion. Our goal is to investigate statistical properties of nuclear level density, define its phenomenological parameters, and offer an affordable and reliable way of calculation.

  16. Neutron Matter from Low to High Density

    E-Print Network [OSTI]

    Gandolfi, Stefano; Carlson, J

    2015-01-01T23:59:59.000Z

    Neutron matter is an intriguing nuclear system with multiple connections to other areas of physics. Considerable progress has been made over the last two decades in exploring the properties of pure neutron fluids. Here we begin by reviewing work done to explore the behavior of very low density neutron matter, which forms a strongly paired superfluid and is thus similar to cold Fermi atoms, though at energy scales differing by many orders of magnitude. We then increase the density, discussing work that ties the study of neutron matter with the determination of the properties of neutron-rich nuclei and neutron-star crusts. After this, we review the impact neutron matter at even higher densities has on the mass-radius relation of neutron stars, thereby making contact with astrophysical observations.

  17. Fabrication of low density ceramic material

    DOE Patents [OSTI]

    Meek, T.T.; Blake, R.D.; Sheinberg, H.

    1985-01-01T23:59:59.000Z

    A precursor mixture and a method of making a low-density ceramic structural material are disclosed. The precursor mixture includes hollow microballoons, typically made of glass, together with a cementing agent capable of being cured by microwave irradiation. A preferred cementing agent is liquid hydrated potassium silicate, which is mixed with the glass microballoons to form a slurry. Upon irradiation the potassium silicate is dehydrated to form a solid porous matrix in which the microballoons are evenly distributed. Ground glass or other filling agents may be included in the slurry to enhance the properties of the final product. Low-density structural ceramics having densities on the order of 0.1 to 0.3 are obtained.

  18. Density matrix of black hole radiation

    E-Print Network [OSTI]

    Lasma Alberte; Ram Brustein; Andrei Khmelnitsky; A. J. M. Medved

    2015-02-09T23:59:59.000Z

    Hawking's model of black hole evaporation is not unitary and leads to a mixed density matrix for the emitted radiation, while the Page model describes a unitary evaporation process in which the density matrix evolves from an almost thermal state to a pure state. We compare a recently proposed model of semiclassical black hole evaporation to the two established models. In particular, we study the density matrix of the outgoing radiation and determine how the magnitude of the off-diagonal corrections differs for the three frameworks. For Hawking's model, we find power-law corrections to the two-point functions that induce exponentially suppressed corrections to the off-diagonal elements of the full density matrix. This verifies that the Hawking result is correct to all orders in perturbation theory and also allows one to express the full density matrix in terms of the single-particle density matrix. We then consider the semiclassical theory for which the corrections, being non-perturbative from an effective field-theory perspective, are much less suppressed and grow monotonically in time. In this case, the R\\'enyi entropy for the outgoing radiation is shown to grow linearly at early times; but this growth slows down and the entropy eventually starts to decrease at the Page time. In addition to comparing models, we emphasize the distinction between the state of the radiation emitted from a black hole, which is highly quantum, and that of the radiation emitted from a typical classical black body at the same temperature.

  19. Configuration Interactions Constrained by Energy Density Functionals

    E-Print Network [OSTI]

    B. Alex Brown; Angelo Signoracci; Morten Hjorth-Jensen

    2010-09-24T23:59:59.000Z

    A new method for constructing a Hamiltonian for configuration interaction calculations with constraints to energies of spherical configurations obtained with energy-density-functional (EDF) methods is presented. This results in a unified model that reproduced the EDF binding-energy in the limit of single-Slater determinants, but can also be used for obtaining energy spectra and correlation energies with renormalized nucleon-nucleon interactions. The three-body and/or density-dependent terms that are necessary for good nuclear saturation properties are contained in the EDF. Applications to binding energies and spectra of nuclei in the region above 208Pb are given.

  20. Josephson oscillations of charge density waves

    SciTech Connect (OSTI)

    Ruvalds, J.; Tua, P.F.

    1985-01-01T23:59:59.000Z

    The formation of charge density waves in solids was originally proposed as a possible mechanism for superconductivity by Froehlich. Although the experimentally discovered materials with charge density waves (CDW)s are found to have finite resistivity as a result of impurity pinning, they nevertheless reveal many interesting features including motion which is analogous to a resistively shunted Josephson junction of superconductors. The noise spectrum of CDW systems is reviewed with particular emphasis on interactions with normal as well as magnetic impurities. Future prospects for observing an amplitude variation of the noise signals induced by a magnetic field are proposed.

  1. Error Analysis in Nuclear Density Functional Theory

    E-Print Network [OSTI]

    Nicolas Schunck; Jordan D. McDonnell; Jason Sarich; Stefan M. Wild; Dave Higdon

    2014-07-11T23:59:59.000Z

    Nuclear density functional theory (DFT) is the only microscopic, global approach to the structure of atomic nuclei. It is used in numerous applications, from determining the limits of stability to gaining a deep understanding of the formation of elements in the universe or the mechanisms that power stars and reactors. The predictive power of the theory depends on the amount of physics embedded in the energy density functional as well as on efficient ways to determine a small number of free parameters and solve the DFT equations. In this article, we discuss the various sources of uncertainties and errors encountered in DFT and possible methods to quantify these uncertainties in a rigorous manner.

  2. Low density, microcellular foams, preparation, and articles

    DOE Patents [OSTI]

    Young, A.T.

    1982-03-03T23:59:59.000Z

    A microcellular low-density foam of poly(4-methyl-1-pentene) particularly useful for forming targets for inertial confinement fusion has been developed. Articles made from the foam have been machined to tolerances of 0.0001 inch, although the densities of the fragile foam are low (about 10 to about 100 mg/cc) and the cell sizes are small (about 10 to about 30 ..mu..m). Methods for forming the foam and articles are given. The yield strength of the foam of the invention is higher than was obtained in other structures of this same material.

  3. Assessment of lesser prairie-chicken lek density relative to landscape characteristics in Texas

    SciTech Connect (OSTI)

    Jennifer Timmer; Matthew Butler; Warren Ballard; Clint Boal; Heather Whitlaw

    2012-08-31T23:59:59.000Z

    My 2.5-yr Master'?s project accomplished the objectives of estimating lesser prairie-chicken (LPC) lek density and abundance in the Texas occupied range and modeling anthropogenic and landscape features associated with lek density by flying helicopter lek surveys for 2 field seasons and employing a line-transect distance sampling method. This project was important for several reasons. Firstly, wildlife managers and biologists have traditionally monitored LPC populations with road-based surveys that may result in biased estimates and do not provide access to privately-owned or remote property. From my aerial surveys and distance sampling, I was able to provide accurate density and abundance estimates, as well as new leks and I detected LPCs outside the occupied range. Secondly, recent research has indicated that energy development has the potential to impact LPCs through avoidance of tall structures, increased mortality from raptors perching on transmission lines, disturbance to nesting hens, and habitat loss/fragmentation. Given the potential wind energy development in the Texas Panhandle, spatial models of current anthropogenic and vegetative features (such as transmission lines, roads, and percent native grassland) influencing lek density were needed. This information provided wildlife managers and wind energy developers in Texas with guidelines for how change in landscape features could impact LPCs. Lastly, LPC populations have faced range-wide declines over the last century and they are currently listed as a candidate species under the Endangered Species Act. I was able to provide timely information on LPC populations in Texas that will be used during the listing process.

  4. Time Dependent Density Functional Theory Application to Extended Systems

    E-Print Network [OSTI]

    Botti, Silvana

    Time Dependent Density Functional Theory Application to Extended Systems Francesco Sottile Facility (ETSF) Donostia, 25 July 2007 Time Dependent Density Functional Theory Francesco Sottile #12 Density Functional Theory Francesco Sottile #12;Linear Periodic systems ALDA The Quest for the Holy

  5. Mechanical constraints enhance electrical energy densities of soft dielectrics

    E-Print Network [OSTI]

    Ferrari, Silvia

    Mechanical constraints enhance electrical energy densities of soft dielectrics Lin Zhang, Qiming, the dielectric will breakdown electrically. The breakdown limits the electrical energy density of the dielectric electric fields and thus increase their electrical energy densities. The mechanical constraints suppress

  6. neutron density. The neutron density (nn) of the source was modeled by solving the simul-

    E-Print Network [OSTI]

    West, Stuart

    neutron density. The neutron density (nn) of the source was modeled by solving the simul- taneousT is the thermal neutron velocity, l is the decay constant, Ns is the s-process abun- dance, bs? is the maxwellian-averaged neutron capture cross-section, and t0 is the average neutron exposure (21). The branching decay of 186Re

  7. On the Determination of the Mean Cosmic Matter Density and the Amplitude of Density Fluctuations

    E-Print Network [OSTI]

    Thomas H. Reiprich

    2002-07-02T23:59:59.000Z

    The cosmological implications from a new estimate of the local X-ray galaxy cluster abundance are summarized. The results are then compared to independent observations. It is suggested that `low' values for the mean cosmic matter density and the amplitude of mass density fluctuations currently do not appear unreasonable observationally.

  8. Theoretical Electron Density Distributions for Fe- and Cu-Sulfide...

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

    Electron Density Distributions for Fe- and Cu-Sulfide Earth Materials: A Connection between Bond Length, Bond Theoretical Electron Density Distributions for Fe- and Cu-Sulfide...

  9. High power density supercapacitors using locally aligned carbon nanotube electrodes

    E-Print Network [OSTI]

    Du, C S; Yeh, J; Pan, Ning

    2005-01-01T23:59:59.000Z

    High power density supercapacitors using locally alignedof high power density supercapacitors and other similarcells [6], and for supercapacitors [718]. As unique energy

  10. Novel and Optimized Materials Phases for High Energy Density...

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

    Novel and Optimized Materials Phases for High Energy Density Batteries Novel and Optimized Materials Phases for High Energy Density Batteries 2013 DOE Hydrogen and Fuel Cells...

  11. TEMPO-based Catholyte for High Energy Density Nonaqueous Redox...

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

    TEMPO-based Catholyte for High Energy Density Nonaqueous Redox Flow Batteries. TEMPO-based Catholyte for High Energy Density Nonaqueous Redox Flow Batteries. Abstract: We will...

  12. High Energy Density Laboratory Plasmas Program | National Nuclear...

    National Nuclear Security Administration (NNSA)

    Photo Gallery Jobs Apply for Our Jobs Our Jobs Working at NNSA Blog Home High Energy Density Laboratory Plasmas Program High Energy Density Laboratory Plasmas Program...

  13. Estimating density of Florida Key deer

    E-Print Network [OSTI]

    Roberts, Clay Walton

    2006-08-16T23:59:59.000Z

    for this species since 1968; however, a need to evaluate the precision of existing and alternative survey methods (i.e., road counts, mark-recapture, infrared-triggered cameras [ITC]) was desired by USFWS. I evaluated density estimates from unbaited ITCs and road...

  14. RICE UNIVERSITY Screened Coulomb Hybrid Density Functionals

    E-Print Network [OSTI]

    Scuseria, Gustavo E.

    in Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy Approved, Thesis Committee-Scuseria-Ernzerhof (HSE) screened Coulomb hybrid density functional is designed to produce exchange energies comparable to traditional hybrids while only using the short range, screened HF exchange. #12;The accuracy of the HSE

  15. THE QCD PHASE DIAGRAM AT FINITE DENSITY.

    SciTech Connect (OSTI)

    SCHMIDT, C.; FODOR, Z.; KATZ, S.

    2005-07-25T23:59:59.000Z

    We study the density of states method to explore the phase diagram of the chiral transition on the temperature and quark chemical potential plane. Four quark flavours are used in the analysis. Though the method is quite expensive small lattices show an indication for a triple-point connecting three different phases on the phase diagram.

  16. Density Functional Theory Approach to Nuclear Fission

    E-Print Network [OSTI]

    N. Schunck

    2013-01-20T23:59:59.000Z

    The Skyrme nuclear energy density functional theory (DFT) is used to model neutron-induced fission in actinides. This paper focuses on the numerical implementation of the theory. In particular, it reports recent advances in DFT code development on leadership class computers, and presents a detailed analysis of the numerical accuracy of DFT solvers for near-scission calculations.

  17. Modern applications of covariant density functional theory

    E-Print Network [OSTI]

    P. Ring; H. Abusara; A. V. Afanasjev; G. A. Lalazissis; T. Niksic; D. Vretenar

    2011-09-19T23:59:59.000Z

    Modern applications of Covariant Density Functional Theory (CDFT) are discussed. First we show a systematic investigation of fission barriers in actinide nuclei within constraint relativistic mean field theory allowing for triaxial deformations. In the second part we discuss a microscopic theory of quantum phase transitions (QPT) based on the relativistic generator coordinate method.

  18. Density Perturbations for Running Cosmological Constant

    E-Print Network [OSTI]

    Julio C. Fabris; Ilya L. Shapiro; Joan Sola

    2007-01-26T23:59:59.000Z

    The dynamics of density and metric perturbations is investigated for the previously developed model where the decay of the vacuum energy into matter (or vice versa) is due to the renormalization group (RG) running of the cosmological constant (CC) term. The evolution of the CC depends on the single parameter \

  19. Drawing Electron Density Maps Tutorial : J. Reibenspies

    E-Print Network [OSTI]

    Meagher, Mary

    file Choose the difference map #12;Step 2 · If necessary generate full molecule in XSEED or XP shift key to pan) #12;Step 4 · All ball and stick plot to spice it up ZOOMED #12;Step 5 · Save screen the electron density in the macocyclic void in order to understand the disorder #12;Step one · In the INS

  20. Density waves in the Calogero model - revisited

    SciTech Connect (OSTI)

    Bardek, V. [Rudjer Boskovic Institute, Bijenicka c.54, HR-10002 Zagreb (Croatia)], E-mail: bardek@irb.hr; Feinberg, J. [Department of Physics, University of Haifa at Oranim, Tivon 36006 (Israel); Department of Physics, Technion-Israel Inst. of Technology, Haifa 32000 (Israel); KITP, University of California, Santa Barbara, CA 93106-4030 (United States)], E-mail: joshua@physics.technion.ac.il; Meljanac, S. [Rudjer Boskovic Institute, Bijenicka c.54, HR-10002 Zagreb (Croatia)], E-mail: meljanac@irb.hr

    2010-03-15T23:59:59.000Z

    The Calogero model bears, in the continuum limit, collective excitations in the form of density waves and solitary modulations of the density of particles. This sector of the spectrum of the model was investigated, mostly within the framework of collective-field theory, by several authors, over the past 15 years or so. In this work we shall concentrate on periodic solutions of the collective BPS-equation (also known as 'finite amplitude density waves'), as well as on periodic solutions of the full static variational equations which vanish periodically (also known as 'large amplitude density waves'). While these solutions are not new, we feel that our analysis and presentation add to the existing literature, as we explain in the text. In addition, we show that these solutions also occur in a certain two-family generalization of the Calogero model, at special points in parameter space. A compendium of useful identities associated with Hilbert transforms, including our own proofs of these identities, appears in Appendix A. In Appendix B we also elucidate in the present paper some fine points having to do with manipulating Hilbert-transforms, which appear ubiquitously in the collective field formalism. Finally, in order to make this paper self-contained, we briefly summarize in Appendix C basic facts about the collective field formulation of the Calogero model.

  1. Photovoltaic retinal prosthesis with high pixel density

    E-Print Network [OSTI]

    Palanker, Daniel

    Photovoltaic retinal prosthesis with high pixel density Keith Mathieson1,4 , James Loudin1 to stimulating electrodes via intraocular cables. We present a photovoltaic subretinal prosthesis, in which pixel, demonstrating the possibility of a fully integrated photovoltaic retinal prosthesis with high

  2. Master's Thesis Density Functional Theory for

    E-Print Network [OSTI]

    Armiento, Rickard

    of the information found during my work. v #12;vi #12;Contents Abstract #12;Abstract This thesis presents a number of results for basic quantum mechanical models intended to be used in the development of density functional theory for systems with edges. Following previous work

  3. Methods to enhance blanket power density

    SciTech Connect (OSTI)

    Hsu, P.Y.; Miller, L.G.; Bohn, T.S.; Deis, G.A.; Longhurst, G.R.; Masson, L.S.; Wessol, D.E.; Abdou, M.A.

    1982-06-01T23:59:59.000Z

    The overall objective of this task is to investigate the extent to which the power density in the FED/INTOR breeder blanket test modules can be enhanced by artificial means. Assuming a viable approach can be developed, it will allow advanced reactor blanket modules to be tested on FED/INTOR under representative conditions.

  4. 80% of the US population lives in urban areas. The increasing population density and expanding area of cities has contributed to pressure from federal and state mandates that

    E-Print Network [OSTI]

    Hall, Sharon J.

    under plants more moist, and spaces between plants more dry. 3. After grass is removed, widely spaced transformations will occur at a higher rate and lead to faster accumulation of inorganic N in soils. Broader-services. · If xeriscapes create a tradeoff between water quality and water use savings, then this type of landscape

  5. ?Linear Gas Jet with Tailored Density Profile"

    SciTech Connect (OSTI)

    KRISHNAN, Mahadevan

    2012-12-10T23:59:59.000Z

    Supersonic, highly collimated gas jets and gas-filled capillary discharge waveguides are two primary targets of choice for Laser Plasma Accelerators (LPA) . Present gas jets have lengths of only 2-4 mm at densities of 1-4E19 cm-3, sufficient for self trapping and electron acceleration to energies up to ~150 MeV. Capillary structures 3 cm long have been used to accelerate beams up to 1 GeV. Capillary discharges used in LPAs serve to guide the pump laser and optimize the energy gain. A wall-stabilized capillary discharge provides a transverse profile across the channel that helps guide the laser and combat diffraction. Gas injection via a fast nozzle at one end provides some longitudinal density control, to improve the coupling. Gas jets with uniform or controlled density profiles may be used to control electron bunch injection and are being integrated into capillary experiments to add tuning of density. The gas jet for electron injection has not yet been optimized. Our Ph-I results have provided the LPA community with an alternative path to realizing a 2-3GeV electron bunch using just a gas jet. For example, our slit/blade combination gives a 15-20mm long acceleration path with tunable density profile, serving as an alternative to a 20-mm long capillary discharge with gas injection at one end. In Ph-II, we will extend these results to longer nozzles, to see whether we can synthesize 30 or 40-mm long plasma channels for LPAs.

  6. Solar flux variability of Mars' exosphere densities and temperatures Jeffrey M. Forbes,1

    E-Print Network [OSTI]

    Forbes, Jeffrey

    Solar flux variability of Mars' exosphere densities and temperatures Jeffrey M. Forbes,1 Frank G, the response of Mars' exosphere to long-term solar change is established and compared to that of Earth conditions) change only 36­50% as much as those at Earth as solar activity increases from solar minimum

  7. Graphene Nucleation Density on Copper: Fundamental Role of Background Pressure Ivan Vlassiouk,*

    E-Print Network [OSTI]

    Feenstra, Randall

    1 Graphene Nucleation Density on Copper: Fundamental Role of Background Pressure Ivan Vlassiouk the effect of background pressure and synthesis temperature on the graphene crystal sizes in chemical vapor of the background pressure and provide the activation energy for graphene nucleation in atmospheric pressure CVD (9

  8. Supernova rates and stellar populations

    E-Print Network [OSTI]

    F. Mannucci

    2007-08-03T23:59:59.000Z

    We discuss the results about the nature of type Ia Supernovae that can be derived by studying their rates in different stellar populations. While the evolution of SN photometry and spectra can constrain the explosion mechanism, the SN rate depends on the progenitor system. We review the current available data on rates as a function of parent galaxy color, morphology, star formation rate, radio luminosity and environment. By studying the variation of the rates with the color of the parent galaxy, a strong evidence was established that type Ia SNe come from both young and old stars. The dependence of the rates with the radio power of the parent galaxy is best reproduced by a bimodal distribution of delay time between the formation of the progenitor and its explosion as a SN. Cluster early-type galaxies show higher type Ia SN rate with respect to field galaxies, and this effect can be due either to traces of young stars or to differences in the delay time distribution.

  9. X-ray populations in galaxies

    E-Print Network [OSTI]

    G. Fabbiano

    2005-11-09T23:59:59.000Z

    Today's sensistive, high resolution Chandra X-ray observations allow the study of many populations of X-ray sources. The traditional astronomical tools of photometric diagrams and luminosity functions are now applied to these populations, and provide the means for classifying the X-ray sources and probing their evolution. While overall stellar mass drives the amount of X-ray binaries in old stellar population, the amount of sources in star-forming galaxies is related to the star formation rate. Shart-lived, luminous, high mass binaries (HNXBs) dominate these young populations.

  10. Stellar populations in bulges of spiral galaxies

    E-Print Network [OSTI]

    P. Jablonka

    1997-03-03T23:59:59.000Z

    We discuss the integrated properties of the stellar population in bulges along the Hubble sequence and new HST data for individual stars in the bulge of M31.

  11. Empirical Prediction Intervals for County Population Forecasts

    E-Print Network [OSTI]

    Rayer, Stefan; Smith, Stanley K.; Tayman, Jeff

    2009-01-01T23:59:59.000Z

    in the determination and prediction of population forecastperformance of empirical prediction intervals? Table 5 shows26, 163184. Empirical Prediction Intervals for County

  12. The problem of the universal density functional and the density matrix functional theory

    SciTech Connect (OSTI)

    Bobrov, V. B., E-mail: vic5907@mail.ru; Trigger, S. A., E-mail: satron@mail.ru [Russian Academy of Sciences, Joint Institute for High Temperatures (Russian Federation)

    2013-04-15T23:59:59.000Z

    The analysis in this paper shows that the Hohenberg-Kohn theorem is the constellation of two statements: (i) the mathematically rigorous Hohenberg-Kohn lemma, which demonstrates that the same ground-state density cannot correspond to two different potentials of an external field, and (ii) the hypothesis of the existence of the universal density functional. Based on the obtained explicit expression for the nonrel-ativistic particle energy in a local external field, we prove that the energy of the system of more than two non-interacting electrons cannot be a functional of the inhomogeneous density. This result is generalized to the system of interacting electrons. It means that the Hohenberg-Kohn lemma cannot provide justification of the universal density functional for fermions. At the same time, statements of the density functional theory remain valid when considering any number of noninteracting ground-state bosons due to the Bose condensation effect. In the framework of the density matrix functional theory, the hypothesis of the existence of the universal density matrix functional corresponds to the cases of noninteracting particles and to interaction in the Hartree-Fock approximation.

  13. The oral health and dental characteristics of a Mimbres population from Southwest New Mexico

    E-Print Network [OSTI]

    Olive, Ben W

    1989-01-01T23:59:59.000Z

    an impact on the susceptibility of teeth to develop dental caries Studies have shown that the chemical composition of teeth changes over time, to become more caries resistant. With inczeasing age, there is a decrease in the density of teeth in con...THE ORAL HEALTH AND DENTAL CHARACTERISTICS OF A MIMBRES POPULATION FROM SOUTHWEST NEW MEXICO A Thesis by BEN WILLIAM OLIVE Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements...

  14. The stability of the MSW solution to the solar neutrino problem with respect to random matter density perturbations

    E-Print Network [OSTI]

    A. Rossi

    1996-05-28T23:59:59.000Z

    We present a generalization of the resonant neutrino conversion in matter, including a random component in the matter density profile. The study is focused on the effect of such matter perturbations upon both large and small mixing angle MSW solutions to the solar neutrino problem. This is carried out both for the active-active $\

  15. Population, Economy and Energy Uses Influence on Sulfur Emissions in the United States Since 1900

    E-Print Network [OSTI]

    Kissock, J. K.; Husar, R. B.

    . The change in sulfur emissions is formulated as a function of changes in these trends. During this century, population growth and increasing economic activity have put upward pressure on sulfur emissions. The declining energy intensity of the economy...

  16. Design for a Longitudinal Density Monitor for the LHC

    E-Print Network [OSTI]

    Bart Pedersen, S; Boccardi, A; Fisher, AS; Jeff, A; Lefevre, T; Rabiller, A; Roncarolo, F; Welsch, CP

    2010-01-01T23:59:59.000Z

    Synchrotron radiation is currently used on the LHC for beam imaging and for monitoring the proton population in the 3 microsecond abort gap. In addition to these existing detectors, a study has been initiated to provide longitudinal density profiles of the LHC beams with a high dynamic range and a 50ps time resolution. This would allow for the precise measurement both of the bunch shape and the number of particles in the bunch tail or drifting into ghost bunches. A solution is proposed based on counting synchrotron light photons with two fast avalanche photo-diodes (APD) operated in Geiger mode. One is free-running but heavily attenuated and can be used to measure the core of the bunch. The other is much more sensitive, for measurement of the bunch tails, but must be gated off during the passage of the bunch to prevent the detector from being swamped. An algorithm is then applied to combine the two measurements and correct for the detector dead-time, after pulsing and pileup effects. Initial results from labo...

  17. Oblique interactions of dust density waves

    SciTech Connect (OSTI)

    Wang, Zhelchui [Los Alamos National Laboratory; Li, Yang - Fang [MAX-PLANCK INSTITUTE; Hou, Lujing [MAX-PLANCK INSTITUTE; Jiang, Ke [MAX-PLANCK INSTITUTE; Wu, De - Jin [CHINA; Thomas, Hubertus M [MAX-PLANCK INSTITUTE; Morfill, Gregor E [MAX-PLANCK INSTITUTE

    2010-01-01T23:59:59.000Z

    Self-excited dust density waves (DDWs) are studied in a striped electrode device. In addition to the usual perpendicularly (with respect to the electrode) propagating DDWs, which have been frequently observed in dusty plasma experiments on the ground, a low-frequency oblique mode is also observed. This low-frequency oblique DDW has a frequency much lower than the dust plasma frequency and its spontaneous excitation is observed even with a very low dust density. It is found that the low-frequency oblique mode can exist either separately or together with the usual perpendicular mode. In the latter case, a new mode arises as a result of the interactions between the perpendicular and the oblique modes. The experiments show that these three modes satisfy the wave coupling conditions in both the frequencies and the wave-vectors.

  18. Global coherence of dust density waves

    SciTech Connect (OSTI)

    Killer, Carsten; Melzer, Andr [Institut fr Physik, Ernst-Moritz-Arndt-Universitt Greifswald, 17489 Greifswald (Germany)

    2014-06-15T23:59:59.000Z

    The coherence of self-excited three-dimensional dust density waves has been experimentally investigated by comparing global and local wave properties. For that purpose, three-dimensional dust clouds have been confined in a radio frequency plasma with thermophoretic levitation. Global wave properties have been measured from the line-of-sight integrated dust density obtained from homogenous light extinction measurements. Local wave properties have been obtained from thin, two-dimensional illuminated laser slices of the cloud. By correlating the simultaneous global and local wave properties, the spatial coherence of the waves has been determined. We find that linear waves with small amplitudes tend to be fragmented, featuring an incoherent wave field. Strongly non-linear waves with large amplitudes, however, feature a strong spatial coherence throughout the dust cloud, indicating a high level of synchronization.

  19. Development of Silica Aerogel with Any Density

    E-Print Network [OSTI]

    M. Tabata; I. Adachi; T. Fukushima; H. Kawai; H. Kishimoto; A. Kuratani; H. Nakayama; S. Nishida; T. Noguchi; K. Okudaira; Y. Tajima; H. Yano; H. Yokogawa; H. Yoshida

    AbstractNew production methods of silica aerogel with high and low refractive indices have been developed. A very slow shrinkage of alcogel at room temperature has made possible producing aerogel with high refractive indices of up to 1.265 without cracks. Even higher refractive indices than 1.08, the transmission length of the aerogel obtained from this technique has been measured to be about 10 to 20 mm at 400 nm wave length. A mold made of alcogel which endures shrinkage in the supercritical drying process has provided aerogel with the extremely low density of 0.009g/cm 3, which corresponds to the refractive index of 1.002. We have succeeded producing aerogel with a wide range of densities. I.

  20. DENSITY FUNCTIONAL THEORY OF NORMAL AND SUPERCONDUCTING ELECTRON LIQUIDS: EXPLICIT

    E-Print Network [OSTI]

    Gross, E.K.U.

    DENSITY FUNCTIONAL THEORY OF NORMAL AND SUPERCONDUCTING ELECTRON LIQUIDS: EXPLICIT FUNCTIONALS VIA?th University Nathan, Queensland 4111, Australia Abstract The basic idea of density functional theory is to map potential which is a functional of the density. The central task of density functional theory is to #12;nd

  1. Energy-momentum Density of Gravitational Waves

    E-Print Network [OSTI]

    Amir M. Abbassi; Saeed Mirshekari

    2014-11-29T23:59:59.000Z

    In this paper, we elaborate the problem of energy-momentum in general relativity by energy-momentum prescriptions theory. Our aim is to calculate energy and momentum densities for the general form of gravitational waves. In this connection, we have extended the previous works by using the prescriptions of Bergmann and Tolman. It is shown that they are finite and reasonable. In addition, using Tolman prescription, exactly, leads to same results that have been obtained by Einstein and Papapetrou prescriptions.

  2. Mapping densities in a noisy state space

    E-Print Network [OSTI]

    Domenico Lippolis

    2013-03-05T23:59:59.000Z

    Weak noise smooths out fractals in a chaotic state space and introduces a maximum attainable resolution to its structure. The balance of noise and deterministic stretching/contraction in each neighborhood introduces local invariants of the dynamics that can be used to partition the state space. We study the local discrete-time evolution of a density in a two-dimensional hyperbolic state space, and use the asymptotic eigenfunctions for the noisy dynamics to formulate a new state space partition algorithm.

  3. High Energy Density Utracapacitors: Low-Cost, High Energy and Power Density, Nanotube-Enhanced Ultracapacitors

    SciTech Connect (OSTI)

    None

    2010-04-01T23:59:59.000Z

    Broad Funding Opportunity Announcement Project: FastCAP is improving the performance of an ultracapacitora battery-like electronic device that can complement, and possibly even replace, an HEV or EV battery pack. Ultracapacitors have many advantages over conventional batteries, including long lifespans (over 1 million cycles, as compared to 10,000 for conventional batteries) and better durability. Ultracapacitors also charge more quickly than conventional batteries, and they release energy more quickly. However, ultracapacitors have fallen short of batteries in one key metric: energy densityhigh energy density means more energy storage. FastCAP is redesigning the ultracapacitors internal structure to increase its energy density. Ultracapacitors traditionally use electrodes made of irregularly shaped, porous carbon. FastCAPs ultracapacitors are made of tiny, aligned carbon nanotubes. The nanotubes provide a regular path for ions moving in and out of the ultracapacitors electrode, increasing the overall efficiency and energy density of the device.

  4. Genetic Diversity and Population Structure of the Arabian Horse Populations from Syria and other Countries

    E-Print Network [OSTI]

    Khanshour, Anas M

    2013-07-05T23:59:59.000Z

    different populations of Arabians representing Middle Eastern and Western populations. The main two aims of this study were to provide the genetic diversity description of Arabians from different origins and to examine the traditional classification system...

  5. Fish Population and Behavior Revealed by Instantaneous

    E-Print Network [OSTI]

    Fish Population and Behavior Revealed by Instantaneous Continental Shelf­Scale Imaging Nicholas C-transect methods from slow-moving research vessels. These methods significantly undersample fish populations in time and space, leaving an incomplete and ambiguous record of abundance and behavior. We show that fish

  6. Calculating Evolutionary Dynamics in Structured Populations

    E-Print Network [OSTI]

    Nowak, Martin A.

    Calculating Evolutionary Dynamics in Structured Populations Charles G. Nathanson1. , Corina E. Here we provide a general formula for calculating evolutionary dynamics in a wide class of structured) Calculating Evolutionary Dynamics in Structured Populations. PLoS Comput Biol 5(12): e1000615. doi:10

  7. Cancer Epidemiology Population Health Sciences 750

    E-Print Network [OSTI]

    Sheridan, Jennifer

    -01/5/11-1 Cancer Epidemiology Population Health Sciences 750 3 credits When: Spring 2011 (1 Audience: This course is intended for students in health-related disciplines interested in cancer etiology. the unequal burden of cancer among populations and variations across time and geography, 2. the distinctive

  8. Reversing Wolbachia-based population replacement

    E-Print Network [OSTI]

    Dobson, Stephen L.

    Wolbachia bacteria as a vehicle for population replace- ment. Also discussed are strategies strategies and provide mechan- isms for the autonomous spread of desired transgenes into the targeted relative to the natural population [15­17]. Primary candidates for gene-drive strategies are autonomous

  9. INSIDE OUT AND UPSIDE DOWN: TRACING THE ASSEMBLY OF A SIMULATED DISK GALAXY USING MONO-AGE STELLAR POPULATIONS

    SciTech Connect (OSTI)

    Bird, Jonathan C.; Kazantzidis, Stelios; Weinberg, David H. [Department of Astronomy, Ohio State University, 140 West 18th Avenue, Columbus, OH 43210 (United States); Guedes, Javiera [Institute for Astronomy, ETH Zuerich, Wolgang-Pauli-Strasse 27, CH-8093 Zuerich (Switzerland); Callegari, Simone [Anthropology Institute and Museum, University of Zuerich, Winterthurerstrasse 190, CH-8057 Zuerich (Switzerland); Mayer, Lucio [Institute for Theoretical Physics, University of Zuerich, Winterthurerstrasse 190, CH-8057 Zuerich (Switzerland); Madau, Piero [Department of Astronomy and Astrophysics, University of California, 1156 High Street, Santa Cruz, CA 95064 (United States)

    2013-08-10T23:59:59.000Z

    We analyze the present day structure and assembly history of a high-resolution hydrodynamic simulation of the formation of a Milky-Way-(MW)-like disk galaxy, from the ''Eris'' simulation suite, dissecting it into cohorts of stars formed at different epochs of cosmic history. At z = 0, stars with t{sub form} < 2 Gyr mainly occupy the stellar spheroid, with the oldest (earliest forming) stars having more centrally concentrated profiles. The younger age cohorts populate disks of progressively longer radial scale lengths and shorter vertical scale heights. At a given radius, the vertical density profiles and velocity dispersions of stars vary smoothly as a function of age, and the superposition of old, vertically extended and young, vertically compact cohorts gives rise to a double-exponential profile like that observed in the MW. Turning to formation history, we find that the trends of spatial structure and kinematics with stellar age are largely imprinted at birth, or immediately thereafter. Stars that form during the active merger phase at z > 3 are quickly scattered into rounded, kinematically hot configurations. The oldest disk cohorts form in structures that are radially compact and relatively thick, while subsequent cohorts form in progressively larger, thinner, colder configurations from gas with increasing levels of rotational support. The disk thus forms ''inside out'' in a radial sense and ''upside down'' in a vertical sense. Secular heating and radial migration influence the final state of each age cohort, but the changes they produce are small compared to the trends established at formation. The predicted correlations of stellar age with spatial and kinematic structure are in good qualitative agreement with the correlations observed for mono-abundance stellar populations in the MW.

  10. Perspective: The Climate-Population-Infrastructure Modeling and Simulation Fertile Area for New Research

    SciTech Connect (OSTI)

    Allen, Melissa R [ORNL; Fernandez, Steven J [ORNL; Walker, Kimberly A [ORNL; Fu, Joshua S [ORNL

    2014-01-01T23:59:59.000Z

    Managing the risks posed by climate change and extreme weather to energy production and delivery is a challenge to communities worldwide. As climate conditions change, populations will shift, and demand will re-locate; and networked infrastructures will evolve to accommodate new load centers, and, hopefully, minimize vulnerability to natural disaster. Climate effects such as sea level rise, increased frequency and intensity of natural disasters, force populations to move locations. Displaced population creates new demand for built infrastructure that in turn generates new economic activity that attracts new workers and associated households to the new locations. Infrastructures and their interdependencies will change in reaction to climate drivers as the networks expand into new population areas and as portions of the networks are abandoned as people leave. Thus, infrastructures will evolve to accommodate new load centers while some parts of the network are underused, and these changes will create emerging vulnerabilities. Forecasting the location of these vulnerabilities by combining climate predictions and agent based population movement models shows promise for defining these future population distributions and changes in coastal infrastructure configurations. By combining climate and weather data, engineering algorithms and social theory it has been only recently possible to examine electricity demand response to increased climactic temperatures, population relocation in response to extreme cyclonic events, consequent net population changes and new regional patterns in electricity demand. These emerging results suggest a research agenda of coupling these disparate modelling approaches to understand the implications of climate change for protecting the nation s critical infrastructure.

  11. Space and time resolved spectroscopy of laser-produced plasmas: A study of density-sensitive x-ray transitions in helium-like and neon-like ions

    SciTech Connect (OSTI)

    Young, Bruce Kai Fong

    1988-09-01T23:59:59.000Z

    The determination of level populations and detailed population mechanisms in dense plasmas has become an increasingly important problem in atomic physics. In this work, the density variation of line intensities and level populations in aluminum K-shell and molybdenum and silver L-shell emission spectra have been measured from high-powered, laser-produced plasmas. For each case, the density dependence of the observed line emission is due to the effect of high frequency electron-ion collisions on metastable levels. The density dependent line intensities vary greatly in laser-produced plasmas and can be used to extract detailed information concerning the population kinetics and level populations of the ions. The laser-plasmas had to be fully characterized in order to clearly compare the observed density dependence with atomic theory predictions. This has been achieved through the combined use of new diagnostic instruments and microdot targets which provided simultaneously space, time, and spectrally resolved data. The plasma temperatures were determined from the slope of the hydrogen-like recombination continuum. The time resolved electron density profiles were measured using multiple frame holographic interferometry. Thus, the density dependence of K-shell spectral lines could be clearly examined, independent of assumptions concerning the dynamics of the plasma. In aluminum, the electron density dependence of various helium-like line intensity ratios were measured. Standard collisional radiative equilibrium models fail to account for the observed density dependence measured for the ''He/sub ..cap alpha..//IC'' ratio. Instead, a quasi-steady state atomic model based on a purely recombining plasma is shown to accurately predict the measured density dependence. This same recombining plasma calculation successfully models the density dependence of the high-n ''He/sub ..gamma..//He/sub ..beta../'' and ''He/sub delta//He/sub ..beta../'' helium-like resonance line intensity ratios.

  12. Population genomics20-02-2009 Antnio Rodrigues; Bruno Santos / 59 Population Genomics

    E-Print Network [OSTI]

    Goldschmidt, Christina

    Population genomics20-02-2009 António Rodrigues; Bruno Santos / 59 Population Genomics 1 António Rodrigues (PDBC 2008) Bruno Santos (PDBC 2008) #12;Population genomics20-02-2009 António Rodrigues; Bruno Santos / 59 Contents 2 2 1000 genome project 1 Motivation and Introduction New generation sequencing

  13. POPULATION ECOLOGY Population Dynamics of the Colorado Potato Beetle in an

    E-Print Network [OSTI]

    POPULATION ECOLOGY Population Dynamics of the Colorado Potato Beetle in an Agroecosystem with Tomatoes and Potatoes with Management Implications to Processing Tomatoes CHRIS L. HARDING,1 S. J Environ. Entomol. 31(6): 1110Ð1118 (2002) ABSTRACT We evaluated the population dynamics of Colorado potato

  14. Why do ultrasoft repulsive particles cluster and crystallize? Analytical results from density functional theory

    E-Print Network [OSTI]

    Christos N. Likos; Bianca M. Mladek; Dieter Gottwald; Gerhard Kahl

    2007-02-22T23:59:59.000Z

    We demonstrate the accuracy of the hypernetted chain closure and of the mean-field approximation for the calculation of the fluid-state properties of systems interacting by means of bounded and positive-definite pair potentials with oscillating Fourier transforms. Subsequently, we prove the validity of a bilinear, random-phase density functional for arbitrary inhomogeneous phases of the same systems. On the basis of this functional, we calculate analytically the freezing parameters of the latter. We demonstrate explicitly that the stable crystals feature a lattice constant that is independent of density and whose value is dictated by the position of the negative minimum of the Fourier transform of the pair potential. This property is equivalent with the existence of clusters, whose population scales proportionally to the density. We establish that regardless of the form of the interaction potential and of the location on the freezing line, all cluster crystals have a universal Lindemann ratio L = 0.189 at freezing. We further make an explicit link between the aforementioned density functional and the harmonic theory of crystals. This allows us to establish an equivalence between the emergence of clusters and the existence of negative Fourier components of the interaction potential. Finally, we make a connection between the class of models at hand and the system of infinite-dimensional hard spheres, when the limits of interaction steepness and space dimension are both taken to infinity in a particularly described fashion.

  15. THE STELLAR NUMBER DENSITY DISTRIBUTION IN THE LOCAL SOLAR NEIGHBORHOOD IS NORTH-SOUTH ASYMMETRIC

    SciTech Connect (OSTI)

    Yanny, Brian [Fermi National Accelerator Laboratory, Batavia, IL 60510 (United States); Gardner, Susan [Department of Physics and Astronomy, University of Kentucky, Lexington, KY 40506-0055 (United States)

    2013-11-10T23:59:59.000Z

    We study the number density distribution of a sample of K and M dwarf stars, matched north and south of the Galactic plane within a distance of 2 kpc from the Sun, using observations from the Ninth Data Release of the Sloan Digital Sky Survey. We determine distances using the photometric parallax method, and in this context systematic effects exist which could potentially impact the determination of the number density profile with height from the Galactic planeand ultimately affect a number density north-south asymmetry. They include: (1) the calibration of the various photometric parallax relations, (2) the ability to separate dwarfs from giants in our sample, (3) the role of stellar population differences such as age and metallicity, (4) the ability to determine the offset of the Sun from the Galactic plane, and (5) the correction for reddening from dust in the Galactic plane, though our stars are at high Galactic latitudes. We find the various analyzed systematic effects to have a negligible impact on our observed asymmetry, and using a new and larger sample of stars we confirm and refine the earlier discovery of Widrow et al. of a significant Galactic north-south asymmetry in the stellar number density distribution.

  16. The ESO Nearby Abell Cluster Survey IX. The morphology-radius and morphology-density relations in rich galaxy clusters

    E-Print Network [OSTI]

    T. Thomas; P. Katgert

    2005-10-10T23:59:59.000Z

    We study the morphology-radius (MR-) and morphology-density (MD-) relations for a sample of about 850 galaxies (with M = -22), the S0 galaxies and the early spirals have different Sigma1-distributions. The reason for this is that Sigma1 is much less correlated with R than is Sigma10, and thus has much less cross-talk from the (MR-) relation. On average, the 'normal' ellipticals populate environments with higher projected density than do the S0 galaxies while the early spirals populate even less dense environments. The segregation of the brightest ellipticals and the late spirals is driven mostly by global factors, while the segregation between 'normal' ellipticals, S0 galaxies and early spirals is driven primarily by local factors.

  17. The red and blue galaxy populations in the GOODS field: evidence for an excess of red dwarfs

    E-Print Network [OSTI]

    S. Salimbeni; E. Giallongo; N. Menci; M. Castellano; A. Fontana; A. Grazian; L. Pentericci; D. Trevese; S. Cristiani; M. Nonino; E. Vanzella

    2007-10-19T23:59:59.000Z

    We study the evolution of the galaxy population up to z\\sim3 as a function of its colour properties. In particular, luminosity functions and luminosity densities have been derived as a function of redshift for the blue/late and red/early populations. We use data from the GOODS-MUSIC catalogue which have typical magnitude limits zred/early subsamples. The LFs of the blue/late and total samples are well represented by steep Schechter functions evolving in luminosity with increasing redshifts. The volume density of the LFs of the red/early populations decreases with increasing redshift. The shape of the red/early LFs shows an excess of faint red dwarfs with respect to the extrapolation of a flat Schechter function and can be represented by the sum of two Schechter functions. Our model for galaxy formation in the hierarchical clustering scenario, which also includes external feedback due to a diffuse UV background, shows a general broad agreement with the LFs of both populations, the larger discrepancies being present at the faint end for the red population. Hints on the nature of the red dwarf population are given on the basis of their stellar mass and spatial distributions.

  18. Method of high-density foil fabrication

    DOE Patents [OSTI]

    Blue, Craig A.; Sikka, Vinod K.; Ohriner, Evan K.

    2003-12-16T23:59:59.000Z

    A method for preparing flat foils having a high density includes the steps of mixing a powdered material with a binder to form a green sheet. The green sheet is exposed to a high intensity radiative source adapted to emit radiation of wavelengths corresponding to an absorption spectrum of the powdered material. The surface of the green sheet is heated while a lower sub-surface temperature is maintained. An apparatus for preparing a foil from a green sheet using a radiation source is also disclosed.

  19. Nuclear Energy Density Optimization: UNEDF2

    E-Print Network [OSTI]

    M. Kortelainen; J. McDonnell; W. Nazarewicz; E. Olsen; P. -G. Reinhard; J. Sarich; N. Schunck; S. M. Wild; D. Davesne; J. Erler; A. Pastore

    2014-10-30T23:59:59.000Z

    The parameters of the UNEDF2 nuclear energy density functional (EDF) model were obtained in an optimization to experimental data consisting of nuclear binding energies, proton radii, odd-even mass staggering data, fission-isomer excitation energies, and single particle energies. In addition to parameter optimization, sensitivity analysis was done to obtain parameter uncertainties and correlations. The resulting UNEDF2 is an all-around EDF. However, the sensitivity analysis also demonstrated that the limits of current Skyrme-like EDFs have been reached and that novel approaches are called for.

  20. Low density inorganic foams fabricated using microwaves

    SciTech Connect (OSTI)

    Meek, T.T.; Blake, R.D.; Gregory, T.G.

    1985-01-01T23:59:59.000Z

    The objective of our work was to determine if high temperature foams could be made using microwave heating; and if so, to investigate some of their properties. Several foams were made and their compressive strengths, tensile strengths and densities were determined. Foams were made of glass, metal-glass, glass-fiber, metal-glass-fiber, and fly ash. The microwave source used was a Litton model 1521 microwave oven which operated at 2.45 GHz and had an output of 700 watts.

  1. Symmetry energy in nuclear density functional theory

    E-Print Network [OSTI]

    W. Nazarewicz; P. -G. Reinhard; W. Satula; D. Vretenar

    2013-07-22T23:59:59.000Z

    The nuclear symmetry energy represents a response to the neutron-proton asymmetry. In this survey we discuss various aspects of symmetry energy in the framework of nuclear density functional theory, considering both non-relativistic and relativistic self-consistent mean-field realizations side-by-side. Key observables pertaining to bulk nucleonic matter and finite nuclei are reviewed. Constraints on the symmetry energy and correlations between observables and symmetry-energy parameters, using statistical covariance analysis, are investigated. Perspectives for future work are outlined in the context of ongoing experimental efforts.

  2. ARM - Lesson Plans: Air Density and Temperature

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May JunDatastreamsmmcrcalgovInstrumentsruc Documentation RUC : XDCResearch Related InformationAcid Rain Outreach Home Room NewsDensity and

  3. Hanford Site Regional Population - 2010 Census

    SciTech Connect (OSTI)

    Hamilton, Erin L.; Snyder, Sandra F.

    2011-08-12T23:59:59.000Z

    The U.S. Department of Energy conducts radiological operations in south-central Washington State. Population dose estimates must be performed to provide a measure of the impact from site radiological releases. Results of the U.S. 2010 Census were used to determine counts and distributions for the residential population located within 50-miles of several operating areas of the Hanford Site. Year 2010 was the first census year that a 50-mile population of a Hanford Site operational area exceeded the half-million mark.

  4. The density of states approach for the simulation of finite density quantum field theories

    E-Print Network [OSTI]

    K. Langfeld; B. Lucini; A. Rago; R. Pellegrini; L. Bongiovanni

    2015-03-02T23:59:59.000Z

    Finite density quantum field theories have evaded first principle Monte-Carlo simulations due to the notorious sign-problem. The partition function of such theories appears as the Fourier transform of the generalised density-of-states, which is the probability distribution of the imaginary part of the action. With the advent of Wang-Landau type simulation techniques and recent advances, the density-of-states can be calculated over many hundreds of orders of magnitude. Current research addresses the question whether the achieved precision is high enough to reliably extract the finite density partition function, which is exponentially suppressed with the volume. In my talk, I review the state-of-play for the high precision calculations of the density-of-states as well as the recent progress for obtaining reliable results from highly oscillating integrals. I will review recent progress for the $Z_3$ quantum field theory for which results can be obtained from the simulation of the dual theory, which appears to free of a sign problem.

  5. Covariant density functional theory for antimagnetic rotation

    E-Print Network [OSTI]

    P. W. Zhao; J. Peng; H. Z. Liang; P. Ring; J. Meng

    2012-05-04T23:59:59.000Z

    Following the previous letter on the first microscopic description of the antimagnetic rotation (AMR) in 105Cd, a systematic investigation and detailed analysis for the AMR band in the frame-work of tilted axis cranking (TAC) model based on covariant density functional theory are carried out. After performing the microscopic and self-consistentTAC calculations with an given density functional, the configuration for the observed AMR band in 105Cd is obtained from the single-particle Routhians. With the configuration thus obtained, the tilt angle for a given rotational frequency is determined self-consistently by minimizing the total Routhian with respect to the tilt angle. In such a way, the energy spectrum, total angular momenta, kinetic and dynamic moments of inertia, and the B(E2) values for the AMR band in 105Cd are calculated. Good agreement with the data is found. By investigating microscopically the contributions from neutrons and protons to the total angular momentum, the "two-shears-like" mechanism in the AMR band is clearly illus-trated. Finally, the currents leading to time-odd mean fields in the Dirac equation are presented and discussed in detail. It is found that they are essentially determined by the valence particles and/or holes. Their spatial distribution and size depend onthe specific single-particle orbitals and the rotational frequency.

  6. Hanford Area 1990 population and 50-year projections. [Appendix contains computer programming for population projections and graphs showing them by grid areas

    SciTech Connect (OSTI)

    Beck, D.M.; Scott, M.J.; Shindle, S.F.; Napier, B.A.; Thurman, A.G.; Batishko, N.C. (Pacific Northwest Lab., Richland, WA (United States)); Davis, M.D. (Westinghouse Hanford Co., Richland, WA (United States)); Pittenger, D.B. (Demographics Lab., Olympia, WA (United States))

    1991-10-01T23:59:59.000Z

    The complex and comprehensive safety analysis activities carried out at Hanford for nonreactor nuclear facilities require data from a number of scientific and engineering disciplines. The types of data that are required include data pertaining to current population and population projections. The types of data found in this document include 1990 census totals for residential population within a 50-mile radius of the 100-N, 200, 300, and 400 Area meteorological towers. This document also contains 50-year projections for residential populations within a 50-mile radius of these four meteorological towers. The analysis of population projections indicates that residential population within a 50-mile radius of the four meteorological towers in question will continue to grow through 2040, although at a slower rate each decade. In all cases, the highest growth is projected for the decade ending in the year 2000. The annual growth rate for this period is projected to be 0.646, 0.633, 0.543, and 0.570 in the 100-N, 200, 300, and 400 Areas, respectively. By 2040, these growth rates are projected to drop to 0.082, 0.068, 0.078, 0.078, respectively. 4 refs., 1 figs., 4 tabs.

  7. Population viability analysis of the Endangered shortnose sturgeon

    SciTech Connect (OSTI)

    Jager, Yetta [ORNL; Bevelhimer, Mark S [ORNL; Peterson, Douglas L. [University of Georgia, Athens, GA

    2011-07-01T23:59:59.000Z

    This study used population viability analysis (PVA) to partition the influences of potential threats to the endangered shortnose sturgeon (Acipenser brevirostrum). A workshop brought together experts to help identify potential threats including groundwater withdrawal, poor water quality, saltwater intrusion, mercury effects, harvest as by-catch, and sedimentation of spawning habitat. During the course of the project, we eliminated some threats and added new ones. Groundwater withdrawal was dismissed after a study failed to identify connection with groundwater and the majority of pumping is from a confined aquifer. We also eliminated activities on Fort Stewart as influences on spawning habitat because any successful spawning must occur upstream of Fort Stewart. We added climate change to the list of threats based on our assessment of temperature effects and expectations of sea-level rise. Our study highlighted the role of populations in nearby rivers in providing metapopulation support, raising the concern that the population in the Ogeechee River acts as a demographic sink. As part of this study, we carried out a field sampling study to analyze effects of training activities on headwater streams. We developed a new methodology for sampling design as part of this effort and used a mixed-modeling approach to identify relationships between land cover-land use, including those associated with military training activity and water quality. We found that tank training was associated with higher suspended sediment and equipment training was associated with higher organic carbon) and water quality. We detected effects of training on suspended sediment and organic carbon. We also carried out a field sampling effort in the Canoochee and Ogeechee Rivers. In the Ogeechee River, we found that dissolved oxygen in 40% of measurements during summer were below 4 mg L-1. To evaluate mercury as a potential threat, we developed a mercury uptake model and analyzed mercury levels in amphipod prey and sturgeon eggs. These did not exceed EPA guidelines. Finally, we developed a PVA model that including linkages between shortnose sturgeon growth, reproduction, and survival and each remaining threat; All three had significant influences. Preliminary simulations suggest that elevated temperatures under future climate will extirpate this population and add support to the hypothesis that this species requires access to spawning habitat far upstream to persist.

  8. E-Print Network 3.0 - activity affects chromosome Sample Search...

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

    is the modification in activities of proteins mediating the chromosome binding and looping. When the protein... The influence of chromosome density variations on the...

  9. Method for spatially distributing a population

    DOE Patents [OSTI]

    Bright, Edward A [Knoxville, TN; Bhaduri, Budhendra L [Knoxville, TN; Coleman, Phillip R [Knoxville, TN; Dobson, Jerome E [Lawrence, KS

    2007-07-24T23:59:59.000Z

    A process for spatially distributing a population count within a geographically defined area can include the steps of logically correlating land usages apparent from a geographically defined area to geospatial features in the geographically defined area and allocating portions of the population count to regions of the geographically defined area having the land usages, according to the logical correlation. The process can also include weighing the logical correlation for determining the allocation of portions of the population count and storing the allocated portions within a searchable data store. The logically correlating step can include the step of logically correlating time-based land usages to geospatial features of the geographically defined area. The process can also include obtaining a population count for the geographically defined area, organizing the geographically defined area into a plurality of sectors, and verifying the allocated portions according to direct observation.

  10. Stellar Populations in Bulges of Spiral Galaxies

    E-Print Network [OSTI]

    P. Jablonka; J. Gorgas; P. Goudfrooij

    2002-02-01T23:59:59.000Z

    We have conducted a spectroscopic analysis of the bulges of a sample of 31 spiral galaxies, spanning the Hubble sequence from S0 to Scd type, in order to study the radial distribution of their stellar population properties.

  11. Population dynamic interference among childhood diseases

    E-Print Network [OSTI]

    Rohani, Pejman

    is predicted and cannot be dismissed in the limited case-study data available for measles and whooping cough in England before the vaccination era. Keywords: measles; whooping cough; population dynamics; epidemiology

  12. Site-Specific Velocity and Density Model for the Waste Treatment Plant, Hanford, Washington.

    SciTech Connect (OSTI)

    Rohay, Alan C.; Brouns, Thomas M.

    2007-06-27T23:59:59.000Z

    This report documents the work conducted under the SBP to develop a shear wave and compressional wave velocity and density model specific to the WTP site. Section 2 provides detailed background information on the WTP site and its underlying geology as well as on the Seismic Boreholes Project activities leading up to the Vs and Vp measurements. In Section 3, methods employed and results obtained are documented for measurements of Vs and Vp velocities in basalts and interbeds. Section 4 provides details on velocity measurements in the sediments underlying the WTP. Borehole gravity measurements of density of the subsurface basalt and sediments are described in Section 5. Section 6 describes the analysis of data presented in section 3-5, and presents the overall velocity and density model for the WTP site.

  13. X-ray source populations in galaxies

    E-Print Network [OSTI]

    G. Fabbiano

    2005-11-16T23:59:59.000Z

    Today's sensitive, high-resolution X-ray observations allow the study of populations of X-ray sources, in the luminosity range of Galactic X-ray binaries, in galaxies as distant as 20-30 Mpc. The traditional astronomical tools of photometric diagrams and luminosity functions are now applied to these populations, providing a direct probe of the evolved binary component of different stellar populations. The study of the X-ray populations of E and S0 galaxies has revamped the debate on the formation and evolution of low-mass X-ray binaries (LMXBs) and on the role of globular clusters in these processes. While overall stellar mass drives the amount of X-ray binaries in old stellar populations, the amount of sources in star forming galaxies is related to the star formation rate. Short-lived, luminous, high-mass binaries (HMXBs) dominate these young populations. The most luminous sources in these systems are the debated ULXs, which have been suggested to be ~100-1000 Msol black holes, but could alternatively include a number of binaries with stellar mass black holes. Very soft sources have also been discovered in many galaxies and their nature is currently being debated. Observations of the deep X-ray sky, and comparison with deep optical surveys, are providing the first evidence of the X-ray evolution of galaxies.

  14. High density Ru nanocrystal deposition for nonvolatile memory applications

    E-Print Network [OSTI]

    High density Ru nanocrystal deposition for nonvolatile memory applications Damon B. Farmer School density optimizes the charge storing capability of the floating layer, while a high degree of size

  15. Wood-Fiber/High-Density-Polyethylene Composites: Compounding Process

    E-Print Network [OSTI]

    Wood-Fiber/High-Density-Polyethylene Composites: Compounding Process J. Z. Lu,1 Q. Wu,1 I. I parameters for the wood-fiber/high-density-polyethylene blends at 60 rpm were a temperature of 180°C

  16. Experimental bond critical point and local energy density properties...

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

    Mn-O, Fe-O and Co-O bonded interactions for Abstract: Bond critical point, bcp, and local energy density properties for the electron density, ED, distributions, calculated with...

  17. Innovative fuel designs for high power density pressurized water reactor

    E-Print Network [OSTI]

    Feng, Dandong, Ph. D. Massachusetts Institute of Technology

    2006-01-01T23:59:59.000Z

    One of the ways to lower the cost of nuclear energy is to increase the power density of the reactor core. Features of fuel design that enhance the potential for high power density are derived based on characteristics of ...

  18. Design of annular fuel for high power density BWRs

    E-Print Network [OSTI]

    Morra, Paolo

    2005-01-01T23:59:59.000Z

    Enabling high power density in the core of Boiling Water Reactors (BWRs) is economically profitable for existing or new reactors. In this work, we examine the potential for increasing the power density in BWR plants by ...

  19. Constrained Density-Functional Theory--Configuration Interaction

    E-Print Network [OSTI]

    Kaduk, Benjamin James

    2012-01-01T23:59:59.000Z

    In this thesis, I implemented a method for performing electronic structure calculations, "Constrained Density Functional Theory-- Configuration Interaction" (CDFT-CI), which builds upon the computational strengths of Density ...

  20. Catalyst activator

    DOE Patents [OSTI]

    McAdon, Mark H. (Midland, MI); Nickias, Peter N. (Midland, MI); Marks, Tobin J. (Evanston, IL); Schwartz, David J. (Lake Jackson, TX)

    2001-01-01T23:59:59.000Z

    A catalyst activator particularly adapted for use in the activation of metal complexes of metals of Group 3-10 for polymerization of ethylenically unsaturated polymerizable monomers, especially olefins, comprising two Group 13 metal or metalloid atoms and a ligand structure including at least one bridging group connecting ligands on the two Group 13 metal or metalloid atoms.

  1. Ternary liquid mixture viscosities and densities

    SciTech Connect (OSTI)

    Wei, I.C.; Rowley, R.L.

    1984-01-01T23:59:59.000Z

    Liquid mixture viscosities and densities have been measured at 298.15 K and ambient pressure for 20 ternary systems. Twelve ternary compositions, encompassing the entire composition range, have been chosen for each system in an effort to test a newly proposed predictive equation based on local compositions. Viscosities calculated by using the local composition model agreed with the experimental data within an average absolute deviation of 6.4%. No adjustable parameters were used and only binary interactions in the form of NRTL constants were input. The results of these studies indicate that the local composition model predictions are generally as good for multicomponent systems as they are for the corresponding binaries. 24 references, 3 tables.

  2. Energy density fluctuations in early universe

    SciTech Connect (OSTI)

    Guardo, G. L.; Ruggieri, M. [Department of Physics and Astronomy, University of Catania, Catania (Italy); Greco, V. [Department of Physics and Astronomy, University of Catania, Catania, Italy and INFN - Laboratori Nazionali del Sud, Catania (Italy)

    2014-05-09T23:59:59.000Z

    The primordial nucleosinthesys of the element can be influenced by the transitions of phase that take place after the Big Bang, such as the QCD transition. In order to study the effect of this phase transition, in this work we compute the time evolution of thermodynamical quantities of the early universe, focusing on temperature and energy density fluctuations, by solving the relevant equations of motion using as input the lattice QCD equation of state to describe the strongly interacting matter in the early universe plasma. We also study the effect of a primordial strong magnetic field by means of a phenomenological equation of state. Our results show that small inhomogeneities of strongly interacting matter in the early Universe are moderately damped during the crossover.

  3. Competition between superconductivity and spin density wave

    E-Print Network [OSTI]

    Tian De Cao

    2012-08-25T23:59:59.000Z

    The Hubbard model has been investigated widely by many authors, while this work may be new in two aspects. One, we focus on the possible effects of the positions of the gaps associated with the pairing and the spin density wave. Two, we suggest that the models with different parameters are appropriate for different materials (or a material in different doped regions). This will lead to some new insights into the high temperature superconductors. It is shown that the SDW can appear at some temperature region when the on-site Coulomb interaction is larger, while the SC requires a decreased U at a lower temperature. This can qualitatively explain the relationship between superconducting and pseudogap states of Cu-based superconductors in underdoped and optimally doped regions. The superinsulator is also discussed.

  4. LATTICE QCD AT FINITE TEMPERATURE AND DENSITY.

    SciTech Connect (OSTI)

    BLUM,T.; CREUTZ,M.; PETRECZKY,P.

    2004-02-24T23:59:59.000Z

    With the operation of the RHIC heavy ion program, the theoretical understanding of QCD at finite temperature and density has become increasingly important. Though QCD at finite temperature has been extensively studied using lattice Monte-Carlo simulations over the past twenty years, most physical questions relevant for RHIC (and future) heavy ion experiments remain open. In lattice QCD at finite temperature and density there have been at least two major advances in recent years. First, for the first time calculations of real time quantities, like meson spectral functions have become available. Second, the lattice study of the QCD phase diagram and equation of state have been extended to finite baryon density by several groups. Both issues were extensively discussed in the course of the workshop. A real highlight was the study of the QCD phase diagram in (T, {mu})-plane by Z. Fodor and S. Katz and the determination of the critical end-point for the physical value of the pion mass. This was the first time such lattice calculations at, the physical pion mass have been performed. Results by Z Fodor and S. Katz were obtained using a multi-parameter re-weighting method. Other determinations of the critical end point were also presented, in particular using a Taylor expansion around {mu} = 0 (Bielefeld group, Ejiri et al.) and using analytic continuation from imaginary chemical potential (Ph. de Forcrand and O. Philipsen). The result based on Taylor expansion agrees within errors with the new prediction of Z. Fodor and S. Katz, while methods based on analytic continuation still predict a higher value for the critical baryon density. Most of the thermodynamics studies in full QCD (including those presented at this workshop) have been performed using quite coarse lattices, a = 0.2-0.3 fm. Therefore one may worry about cutoff effects in different thermodynamic quantities, like the transition temperature T{sub tr}. At the workshop U. Heller presented a study of the transition temperature for three different lattice spacings and performed a continuum extrapolation of T{sub tr} for the first time. Lattice calculations of the meson spectral functions were presented by M. Asakawa, S. Datta, E. Laermann and H. Matsufuru. These show that charmonia ground states ({eta}{sub c} and J/{psi}) continue to exist in the plasma at least up to a temperature of 1.7 T{sub tr}. At what temperature charmonia states cease to exist is not yet clear. Calculations presented by M. Asakawa show dissolution of the J/{psi} at T = 1.7 T{sub tr}, while the analysis presented H. Matsufuru provided evidence that ground state charmonia still exist at this temperature. S. Datta argued that the ground state charmonia is likely to dissolve only for temperatures T > 2.25 T{sub tr}, while the P-states are dissociated at, 1.1 T{sub tr}. It is also very interesting that, even in the case of light quarks, meson spectral functions show a resonance-like structure in the plasma phase (talk by E. Laermann). Finally attempts to calculate transport properties in the Quark Gluon Plasma were presented by S. Gupta. The workshop devoted special attention to the finite temperature modification of inter-quark forces and color screening, another area where considerable progress has been made in recent years (talks by 0. Kaczmarek, K. Petrov, O. Philipsen and F. Zantow). Many other new theoretical developments which cannot be discussed here were also presented on the workshop. Altogether the workshop was a great success, for which we thank all the participants.

  5. Superfluid Local Density Approximation: A Density Functional Theory Approach to the Nuclear Pairing Problem

    E-Print Network [OSTI]

    Aurel Bulgac

    2012-04-10T23:59:59.000Z

    I describe the foundation of a Density Functional Theory approach to include pairing correlations, which was applied to a variety of systems ranging from dilute fermions, to neutron stars and finite nuclei. Ground state properties as well as properties of excited states and time-dependent phenomena can be achieved in this manner within a formalism based on microscopic input.

  6. Quantum coherent switch utilizing commensurate nanoelectrode and charge density periodicities

    DOE Patents [OSTI]

    Harrison, Neil (Santa Fe, NM); Singleton, John (Los Alamos, NM); Migliori, Albert (Santa Fe, NM)

    2008-08-05T23:59:59.000Z

    A quantum coherent switch having a substrate formed from a density wave (DW) material capable of having a periodic electron density modulation or spin density modulation, a dielectric layer formed onto a surface of the substrate that is orthogonal to an intrinsic wave vector of the DW material; and structure for applying an external spatially periodic electrostatic potential over the dielectric layer.

  7. ORIGINAL PAPER BambooFiber Filled High Density Polyethylene Composites

    E-Print Network [OSTI]

    ORIGINAL PAPER Bamboo­Fiber Filled High Density Polyethylene Composites: Effect of Coupling Springer Science+Business Media, LLC 2008 Abstract High density polyethylene (HDPE)/bamboo composites in the future study. Keywords Bamboo Á High density polyethylene Á Coupling treatment Á Nanoclay Introduction

  8. HIGHLIGHT OF THE MONTH Orbital Functionals in Density Functional Theory

    E-Print Network [OSTI]

    Gross, E.K.U.

    HIGHLIGHT OF THE MONTH Orbital Functionals in Density Functional Theory: The Optimized E#11;ectiveurzburg, Am Hubland, D-97074 Wurzburg, Germany The success of density functional theory hinges the development of modern density functional theory. In present-day language, the exact OEP should be called

  9. Electronic excitations in complex systems: beyond density functional theory

    E-Print Network [OSTI]

    Botti, Silvana

    Electronic excitations in complex systems: beyond density functional theory for real materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 3 Time-dependent density functional theory 19 3.1 The Runge-Gross theorem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 4 Model kernels from many-body perturbation theory 29 4.1 Time-dependent density functional theory

  10. A Guided Tour of TimeDependent Density Functional Theory

    E-Print Network [OSTI]

    Gross, E.K.U.

    A Guided Tour of Time­Dependent Density Functional Theory Kieron Burke 1 and E.K.U. Gross 2 1 outlook. 1 Introduction and User's Guide Density functional theory is the study of the one in density functional theory, driven largely by its applications in quantum chemistry[3]. This is due

  11. EFFECTIVE MAXWELL EQUATIONS FROM TIME-DEPENDENT DENSITY FUNCTIONAL THEORY

    E-Print Network [OSTI]

    Bigelow, Stephen

    EFFECTIVE MAXWELL EQUATIONS FROM TIME-DEPENDENT DENSITY FUNCTIONAL THEORY WEINAN E, JIANFENG LU and magnetic fields are derived starting from time-dependent density functional theory. Effective permittivity with the density functional theory [2­4] instead of the many-body Schr¨odinger or Dirac equations. This is because

  12. Density Functional Theory applied to the solid state...

    E-Print Network [OSTI]

    Adler, Joan

    Density Functional Theory applied to the solid state... An introduction to VASP Jeremie Zaffran 2nd Marom (PhD) #12;Contents I- DFT and its functionals A. On the density functional theory... B #12;I- DFT and its functionals #12;I-DFT and its functionals A- On the density functional theory Why

  13. Benchmark density functional theory calculations for nanoscale conductance

    E-Print Network [OSTI]

    Thygesen, Kristian

    Benchmark density functional theory calculations for nanoscale conductance M. Strange,a I. S. The transmission functions are calculated using two different density functional theory methods, namely state density functional theory DFT . The resulting NEGF- DFT formalism provides a numerically efficient

  14. 1 Density Functional Theory for Emergents Robert O. Jones

    E-Print Network [OSTI]

    1 Density Functional Theory for Emergents Robert O. Jones Peter-Gr¨unberg-Institut PGI-1 and German the widespread use of density functional (DF) theory in materials science and chemistry and the physical insight as basic variable 3 3 An "approximate practical method" 5 4 Density functional formalism 7 4.1 Single

  15. THE MANY-ELECTRON ENERGY IN DENSITY FUNCTIONAL THEORY

    E-Print Network [OSTI]

    Armiento, Rickard

    THE MANY-ELECTRON ENERGY IN DENSITY FUNCTIONAL THEORY From Exchange-Correlation Functional Design to the configuration of its electrons. Computer programs based on density functional theory (DFT) can calculate applicable within the field of computational density functional theory. Sammanfattning Att förutsäga

  16. Time Dependent Density Functional Theory Applications, limitations and ... new frontiers

    E-Print Network [OSTI]

    Botti, Silvana

    Time Dependent Density Functional Theory Applications, limitations and ... new frontiers Francesco Spectroscopy Facility (ETSF) Vienna, 19 January 2007 1/55 Time Dependent Density Functional Theory Francesco Sottile #12;Time-Dependent Density Functional Theory Applications and results: The ETSF Outline 1 Time

  17. RELATIVISTIC DENSITY FUNCTIONAL THEORY: FOUNDATIONS AND BASIC FORMALISM

    E-Print Network [OSTI]

    Engel, Eberhard

    1 Chapter 10 RELATIVISTIC DENSITY FUNCTIONAL THEORY: FOUNDATIONS AND BASIC FORMALISM E. Engela a An overview of relativistic density functional theory (RDFT) is presented with special emphasis on its field-Cluster schemes in recent years density functional theory (DFT) still represents the method of choice

  18. Inverse diffusion from knowledge of power densities Guillaume Bal

    E-Print Network [OSTI]

    Bal, Guillaume

    asymptotic expansions and (Fourier) transformation, this allow us to construct the power density) provides access to the power density H(x) = (x)|u|2 (x) for all x inside the domain of interestInverse diffusion from knowledge of power densities Guillaume Bal , Eric Bonnetier , Fran

  19. Density of the Values Set of the Tau Function

    E-Print Network [OSTI]

    N. A. Carella

    2014-04-10T23:59:59.000Z

    It is shown that the density of the values set {Tau(n): n > x/log x. The currently known density is #{Tau(n) : n > x^(1/2+o(1)), and the expected density is #{Tau(n) : n 2, which arises as a singular case of this analysis, is discussed within.

  20. Synconset Waves and Chains: Spiking Onsets in Synchronous Populations Predict and Are Predicted by

    E-Print Network [OSTI]

    Narayanan, Rishikesh

    Synconset Waves and Chains: Spiking Onsets in Synchronous Populations Predict and Are Predicted Synfire waves are propagating spike packets in synfire chains, which are feedforward chains embedded in random networks. Although synfire waves have proved to be effective quantification for network activity

  1. A Multi-Resolution Large Population Game Framework for Smart Grid Demand Response Management

    E-Print Network [OSTI]

    Boyer, Edmond

    A Multi-Resolution Large Population Game Framework for Smart Grid Demand Response Management Quanyan Zhu and Tamer Bas¸ar Abstract--Dynamic demand response (DR) management is becoming an integral, active operation, and efficient demand response. A reliable and efficient communication and networking

  2. Brain covariance selection: better individual functional connectivity models using population prior

    E-Print Network [OSTI]

    Brain covariance selection: better individual functional connectivity models using population prior.thirion@inria.fr Abstract Spontaneous brain activity, as observed in functional neuroimaging, has been shown to display reproducible structure that expresses brain architecture and car- ries markers of brain pathologies

  3. Impacts of Climate Change and Population Growth on Water Stress Becky Witte

    E-Print Network [OSTI]

    Fay, Noah

    Impacts of Climate Change and Population Growth on Water Stress by Becky Witte Master's Student shift toward urban areas, current water and wastewater treatment systems may not be adequate to address climate change, energy consumption, pollution, and impacts of human activities on ecosystems. Addressing

  4. Effect of electron-density gradients on propagation of radio waves in the mid-latitude trough. Master's thesis

    SciTech Connect (OSTI)

    Citrone, P.J.

    1991-01-01T23:59:59.000Z

    Partial contents of this thesis include: (1) Radio-wave propagation and the mid-latitude trough; (2) Ionospheric measurements; (3) Modification of time-dependent ionospheric model output with latitudinal electron-density profiles from digisonde trough depictions; (4) Ray-tracing simulations to examine ground range; and (5) Effects of three-dimensional gradients in electron density on radio-wave propagation in the trough region. Data is tabulated for geophysical conditions, solar activity level, geomagnetic activity level, conditions for vertical ray refraction to surface, and ray-tracing fixed-input conditions.

  5. E-Print Network 3.0 - atomic oxygen densities Sample Search Results

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

    densities Search Powered by Explorit Topic List Advanced Search Sample search results for: atomic oxygen densities...

  6. E-Print Network 3.0 - atomic oxygen density Sample Search Results

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

    density Search Powered by Explorit Topic List Advanced Search Sample search results for: atomic oxygen density...

  7. Dworshak Kokanee Population and Engrainment Assessment : 2006 Annual Report, March 1, 2006 - February 28, 2007.

    SciTech Connect (OSTI)

    Stark, Eric J.

    2008-12-18T23:59:59.000Z

    During this contract, we continued testing underwater strobe lights to determine their effectiveness at repelling kokanee Oncorhynchus nerka away from Dworshak Dam. Strobe light tests were conducted on four nights from April 24-27, 2006, in front of the middle reservoir outlet (RO) 2. The density and distribution of fish, (thought to be mostly kokanee), were monitored with a split-beam echo sounder. We then compared fish counts and densities during nights when the lights were flashing to counts and densities during adjacent nights without the lights on. On two nights, April 25 and 27, 2006, when no lights were present, fish counts near RO 2 averaged 12.4 fish and densities averaged 31.0 fish/ha. When strobe lights were turned on during the nights of April 24 and 26, mean counts dropped to 4.7 fish and densities dropped to 0.5 fish/ha. The decline in counts (62%) and densities (99%) was statistically significant (p = 0.009 and 0.002, respectively). Test results indicated that strobe lights were able to reduce fish densities by at least 50% in front of a discharging reservoir outlet, which would be sufficient to improve sport fish harvest. We also used split-beam hydroacoustics to monitor the kokanee population in Dworshak Reservoir during 2006. Estimated abundance of kokanee increased from the 2005 population estimate. Based on hydroacoustic surveys, we estimated approximately 5,815,000 kokanee (90% CI {+-} 27.6%) in Dworshak Reservoir in August 2006. This included 2,183,000 age-0 (90% CI {+-} 24.2%), 1,509,000 age-1 (90% CI {+-} 29.0%), and 2,124,000 age-2 (90% CI {+-} 27.6%) kokanee. This resulted in a density of age-2 kokanee above the management goal of 30-50 adults/ha. Entrainment sampling was conducted with fixed-site, split-beam hydroacoustics from May through September for a continuous 24 h period when dam operations permitted. The highest fish detection rates from entrainment assessments were found during dawn periods, unlike previous year's results, which were highest during nighttime. The lowest detection rate was found during the day period, which was consistent with previous findings. Fish detection rates were generally low during high discharges throughout the summer and highest during low discharges in May and June. Low detection rates were found during high discharge periods during drawdowns for anadromous fish flows in July and August, which resulted in low susceptibility to entrainment. Counts of spawning kokanee in four tributary streams totaled 29,743 fish. These data fit the previously developed relationship between spawner counts and adult kokanee abundance in the reservoir.

  8. Gluon condensation and deconfinement critical density in nuclear matter

    E-Print Network [OSTI]

    M. Baldo; P. Castorina; D. Zappala'

    2004-10-07T23:59:59.000Z

    An upper limit to the critical density for the transition to the deconfined phase, at zero temperature, has been evaluated by analyzing the behavior of the gluon condensate in nuclear matter. Due to the non linear baryon density effects, the upper limit to the critical density, \\rho_c turns out about nine times the saturation density, rho_0 for the value of the gluon condensate in vacuum =0.012 GeV^4. For neutron matter \\rho_c \\simeq 8.5 \\rho_0. The dependence of the critical density on the value of the gluon condensate in vacuum is studied.

  9. An analysis of numerical trends in African elephant populations.

    E-Print Network [OSTI]

    Junker, Jessica

    2009-01-01T23:59:59.000Z

    ?? The elephant debate deals largely with population size, how elephant numbers change over time, how they may affect vegetation, and how their populations should (more)

  10. A multi-population genetic algorithm for a constrained two ...

    E-Print Network [OSTI]

    2008-12-10T23:59:59.000Z

    tree search algorithm for solving the d-dimensional knapsack problem. ...... PH A population heuristic, proposed by Beasley (2004), where a population of.

  11. Will China's Vehicle Population Grow Even Faster than Forecasted?

    E-Print Network [OSTI]

    Wang, Yunshi; Teter, Jacob; Sperling, Daniel

    2012-01-01T23:59:59.000Z

    2011. Chinas Soaring Vehicle Population: Even Greater Thanversion, Chinas Soaring Vehicle Population: Even Greater2012. Modeling Future Vehicle Sales and Stock in China,

  12. STAR CLUSTER POPULATIONS IN THE OUTER DISKS OF NEARBY GALAXIES

    SciTech Connect (OSTI)

    Herbert-Fort, Stephane; Zaritsky, Dennis [Department of Astronomy/Steward Observatory, University of Arizona, 933 N Cherry Avenue, Tucson, AZ 85721 (United States); Moustakas, John [Center for Astrophysics and Space Sciences, University of California, San Diego, La Jolla, CA 92093 (United States); Di Paola, Andrea [INAF, Osservatorio Astronomico di Roma, via di Frascati 33, I-00040 Monteporzio (Italy); Pogge, Richard W. [Department of Astronomy, Ohio State University, 140 W. 18th Avenue, Columbus, OH 43210-1173 (United States); Ragazzoni, Roberto, E-mail: s.herbertfort@gmail.com, E-mail: dennis.zaritsky@gmail.com [INAF, Osservatorio Astronomico di Padova, vicolo dell'Osservatorio 5, I-35122 Padova (Italy)

    2012-08-01T23:59:59.000Z

    We present a Large Binocular Telescope imaging study that characterizes the star cluster component of nearby galaxy outer disks (beyond the optical radius R{sub 25}). Expanding on the pilot project of Herbert-Fort et al., we present deep ({approx}27.5 mag V-band point-source limiting magnitude) U- and V-band imaging of six galaxies: IC 4182, NGC 3351, NGC 4736, NGC 4826, NGC 5474, and NGC 6503. We find that the outer disk of each galaxy is populated with marginally resolved star clusters with masses {approx}10{sup 3} M{sub Sun} and ages up to {approx}1 Gyr (masses and ages are limited by the depth of our imaging and uncertainties are large given how photometry can be strongly affected by the presence or absence of a few stars in such low-mass systems), and that they are typically found out to at least 2 R{sub 25} but sometimes as far as 3-4 R{sub 25}-even beyond the apparent H I disk. The mean rate of cluster formation for 1 R{sub 25} {<=} R {<=} 1.5 R{sub 25} is at least one every {approx}2.5 Myr and the clusters are spatially correlated with the H I, most strongly with higher density gas near the periphery of the optical disk and with lower density neutral gas at the H I disk periphery. We hypothesize that the clusters near the edge of the optical disk are formed in the extension of spiral structure from the inner disk and are a fairly consistent phenomenon and that the clusters formed at the periphery of the H I disk are the result of accretion episodes.

  13. Galaxy density profiles and shapes -- II. selection biases in strong lensing surveys

    E-Print Network [OSTI]

    Rachel Mandelbaum; Glenn van de Ven; Charles R. Keeton

    2009-06-18T23:59:59.000Z

    [Abridged] Many current and future astronomical surveys will rely on samples of strong gravitational lens systems to draw conclusions about galaxy mass distributions. We use a new strong lensing pipeline (presented in Paper I of this series) to explore selection biases that may cause the population of strong lensing systems to differ from the general galaxy population. Our focus is on point-source lensing by early-type galaxies with two mass components (stellar and dark matter) that have a variety of density profiles and shapes motivated by observational and theoretical studies of galaxy properties. We seek not only to quantify but also to understand the physics behind selection biases related to: galaxy mass, orientation and shape; dark matter profile parameters such as inner slope and concentration; and adiabatic contraction. We study how all of these properties affect the lensing Einstein radius, total cross-section, quad/double ratio, and image separation distribution. We find significant (factors of several) selection biases with mass; orientation, for a given galaxy shape at fixed mass; cusped dark matter profile inner slope and concentration; concentration of the stellar and dark matter deprojected Sersic models. Interestingly, the intrinsic shape of a galaxy does not strongly influence its lensing cross-section when we average over viewing angles. Our results are an important first step towards understanding how strong lens systems relate to the general galaxy population.

  14. Population inversion in Landau-quantized graphene

    E-Print Network [OSTI]

    Wendler, Florian

    2014-01-01T23:59:59.000Z

    Landau level lasers have the advantage of tunability of the laser frequency by means of the external magnetic field. The crucial prerequisite of such a laser is a population inversion between optically coupled Landau levels. Efficient carrier-carrier and carrier-phonon scattering generally suppresses this effect in conventional materials. Based on microscopic calculations, we predict for the first time the occurrence of a long-lived population inversion in Landau-quantized graphene and reveal the underlying many-particle mechanisms. To guide the experimental demonstration, we present optimal conditions for the observation of a maximal population inversion in terms of experimentally accessible parameters, such as the strength of the magnetic field, pump fluence, temperature, and doping. We reveal that in addition to the tunability of the Landau-level laser frequency, also the polarization of the emitted light can be tuned via gate voltage controlling the doping of the sample.

  15. Fabrication Flaw Density and Distribution In Repairs to Reactor Pressure Vessel and Piping Welds

    SciTech Connect (OSTI)

    GJ Schuster, FA Simonen, SR Doctor

    2008-04-01T23:59:59.000Z

    The Pacific Northwest National Laboratory is developing a generalized fabrication flaw distribution for the population of nuclear reactor pressure vessels and for piping welds in U.S. operating reactors. The purpose of the generalized flaw distribution is to predict component-specific flaw densities. The estimates of fabrication flaws are intended for use in fracture mechanics structural integrity assessments. Structural integrity assessments, such as estimating the frequency of loss-of-coolant accidents, are performed by computer codes that require, as input, accurate estimates of flaw densities. Welds from four different reactor pressure vessels and a collection of archived pipes have been studied to develop empirical estimates of fabrication flaw densities. This report describes the fabrication flaw distribution and characterization in the repair weld metal of vessels and piping. This work indicates that large flaws occur in these repairs. These results show that repair flaws are complex in composition and sometimes include cracks on the ends of the repair cavities. Parametric analysis using an exponential fit is performed on the data. The relevance of construction records is established for describing fabrication processes and product forms. An analysis of these records shows there was a significant change in repair frequency over the years when these components were fabricated. A description of repair flaw morphology is provided with a discussion of fracture mechanics significance. Fabrication flaws in repairs are characterized using optimized-access, high-sensitivity nondestructive ultrasonic testing. Flaw characterizations are then validated by other nondestructive evaluation techniques and complemented by destructive testing.

  16. Conducting polymers as potential active materials in electrochemical supercapacitors

    SciTech Connect (OSTI)

    Rudge, A.; Davey, J.; Raistrick, I.; Gottesfeld, S. [Los Alamos National Lab., NM (United States); Ferraris, J.P. [Texas Univ., Richardson, TX (United States). Dept. of Chemistry

    1992-12-01T23:59:59.000Z

    Electronically,conducting polymers represent an interesting class of materials for use in electrochemical capacitors because of the combination of high capacitive energy density and low materials cost. Three generalized types of electrochemical capacitors can be constructed using conducting polymers as active material, and in the third of these, which utilizes conducting polymers that can be both n- and p-doped, energy densities of up to 40 watt-hours per kilogram of active material on both electrodes have been demonstrated.

  17. Conducting polymers as potential active materials in electrochemical supercapacitors

    SciTech Connect (OSTI)

    Rudge, A.; Davey, J.; Raistrick, I.; Gottesfeld, S. (Los Alamos National Lab., NM (United States)); Ferraris, J.P. (Texas Univ., Richardson, TX (United States). Dept. of Chemistry)

    1992-01-01T23:59:59.000Z

    Electronically,conducting polymers represent an interesting class of materials for use in electrochemical capacitors because of the combination of high capacitive energy density and low materials cost. Three generalized types of electrochemical capacitors can be constructed using conducting polymers as active material, and in the third of these, which utilizes conducting polymers that can be both n- and p-doped, energy densities of up to 40 watt-hours per kilogram of active material on both electrodes have been demonstrated.

  18. Building a Universal Nuclear Energy Density Functional

    SciTech Connect (OSTI)

    Carlson, Joe A. [Michigan State University; Furnstahl, Dick; Horoi, Mihai; Lust, Rusty; Nazaewicc, Witek; Ng, Esmond; Thompson, Ian; Vary, James

    2012-12-30T23:59:59.000Z

    During the period of Dec. 1 2006 Jun. 30, 2012, the UNEDF collaboration carried out a comprehensive study of all nuclei, based on the most accurate knowledge of the strong nuclear interaction, the most reliable theoretical approaches, the most advanced algorithms, and extensive computational resources, with a view towards scaling to the petaflop platforms and beyond. The long-term vision initiated with UNEDF is to arrive at a comprehensive, quantitative, and unified description of nuclei and their reactions, grounded in the fundamental interactions between the constituent nucleons. We seek to replace current phenomenological models of nuclear structure and reactions with a well-founded microscopic theory that delivers maximum predictive power with well-quantified uncertainties. Specifically, the mission of this project has been three-fold: ? First, to find an optimal energy density functional (EDF) using all our knowledge of the nucleonic Hamiltonian and basic nuclear properties; ? Second, to apply the EDF theory and its extensions to validate the functional using all the available relevant nuclear structure and reaction data; ? Third, to apply the validated theory to properties of interest that cannot be measured, in particular the properties needed for reaction theory.

  19. Balanced homodyne detectors and Casimir energy densities

    E-Print Network [OSTI]

    P. Marecki

    2008-03-22T23:59:59.000Z

    We recall and generalize the analysis of the output of the so-called balanced homodyne detectors. The most important feature of these detectors is their ability to quantify the vacuum fluctuations of the electric field, that is expectation values of products of (quantum-) electric-field operators. More precisely, the output of BHDs provides information on the one- and two-point functions of arbitrary states of quantum fields. We generalize the analysis of the response of BHDs to the case of quantum fields under influence of static external conditions such as cavities or polarizable media. By recalling the expressions for two-point functions of quantum fields in Casimir geometries we show, that a rich, position- and frequency-dependent pattern of BHD responses is predicted for ground states. This points to a potentially new characterization of quantum fields in Casimir setups which would not only complement the current global methods (Casimir forces), but also improve understanding of sub-vacuum energy densities present in some regions in these geometries.

  20. Operator pencils on the algebra of densities

    E-Print Network [OSTI]

    A. Biggs; H. M. Khudaverdian

    2014-10-15T23:59:59.000Z

    In this paper we continue to study equivariant pencil liftings and differential operators on the algebra of densities. We emphasize the role that the geometry of the extended manifold plays. Firstly we consider basic examples. We give a projective line of diff($M$)-equivariant pencil liftings for first order operators, and the canonical second order self-adjoint lifting. Secondly we study pencil liftings equivariant with respect to volume preserving transformations. This helps to understand the role of self-adjointness for the canonical pencils. Then we introduce the Duval-Lecomte-Ovsienko (DLO)-pencil lifting which is derived from the full symbol calculus of projective quantisation. We use the DLO-pencil lifting to describe all regular proj-equivariant pencil liftings. In particular the comparison of these pencils with the canonical pencil for second order operators leads to objects related to the Schwarzian. Within this paper the question of whether the pencil lifting factors through a full symbol map naturally arises.

  1. Probing the density dependence of symmetry energy at subsaturation density with HICs

    E-Print Network [OSTI]

    Zhang, Yingxun; Li, Zhuxia; Danielewicz, P; Lynch, W G; Lu, Xiaohua

    2009-01-01T23:59:59.000Z

    The reaction mechanism of the central collisions and peripheral collisions for $^{112,124}Sn+^{112,124}Sn$ at $E/A=50MeV$ is investigated within the framework of the Improved Quantum Molecular Dynamics model. The results show that multifragmentation process is an important mechanism at this energy region, and the influence of the cluster emission on the double n/p ratios and the isospin transport ratio are important. Furthermore, three observables, double n/p ratios, isospin diffusion and the rapidity distribution of the ratio $R_{7}$ for $^{112,124}Sn+^{112,124}Sn$ at E/A=50MeV are analyzed with the Improved Quantum Molecular Dynamics model. The results show that these three observables are sensitive to the density dependence of the symmetry energy. By comparing the calculation results to the data, the consistent constraint on the density dependence of the symmetry energy from these three observables is obtained.

  2. Probing the density dependence of symmetry energy at subsaturation density with HICs

    E-Print Network [OSTI]

    Yingxun Zhang; M. B. Tsang; Zhuxia Li; P. Danielewicz; W. G. Lynch; Xiaohua Lu

    2009-11-09T23:59:59.000Z

    The reaction mechanism of the central collisions and peripheral collisions for $^{112,124}Sn+^{112,124}Sn$ at $E/A=50MeV$ is investigated within the framework of the Improved Quantum Molecular Dynamics model. The results show that multifragmentation process is an important mechanism at this energy region, and the influence of the cluster emission on the double n/p ratios and the isospin transport ratio are important. Furthermore, three observables, double n/p ratios, isospin diffusion and the rapidity distribution of the ratio $R_{7}$ for $^{112,124}Sn+^{112,124}Sn$ at E/A=50MeV are analyzed with the Improved Quantum Molecular Dynamics model. The results show that these three observables are sensitive to the density dependence of the symmetry energy. By comparing the calculation results to the data, the consistent constraint on the density dependence of the symmetry energy from these three observables is obtained.

  3. A Decade of Population Change in Texas.

    E-Print Network [OSTI]

    Skrabanek, R. L.

    1963-01-01T23:59:59.000Z

    of community facilities. The political representation of rural dwellers is also likely to be reduced. 3. In 1960, for the first time in history, Texas had more females than males. The projected sex ratio is 96.7 males per 100 females in 1970. At the same... of the Panhandle and extending southward beyond Abilene. This area sustained a decline of one-third in rural population during the decade. Only 2 of the 29 counties (Cottle and Donley) in area 6 had an increase in rural population. Another section, state...

  4. New possible resonance for population II Cepheids

    SciTech Connect (OSTI)

    Cox, A.N.; Kidman, R.B.

    1984-01-01T23:59:59.000Z

    Light and velocity curves of some radial mode variable stars seem to indicate a resonance where the second overtone has a period exactly half that of the fundamental mode. The two classes of stars that show this resonance by bumps in their light curves are the classical Cepheids and the population II BL Her variables. We here propose that there is another resonance for the population II W Vir variables where the ratio of the first overtone to the fundamental periods is 0.5.

  5. Current density partitioning in time-dependent current density functional theory

    SciTech Connect (OSTI)

    Mosquera, Martn A. [Department of Chemistry, Purdue University, West Lafayette, Indiana 47907 (United States)] [Department of Chemistry, Purdue University, West Lafayette, Indiana 47907 (United States); Wasserman, Adam, E-mail: awasser@purdue.edu [Department of Chemistry, Purdue University, West Lafayette, Indiana 47907 (United States) [Department of Chemistry, Purdue University, West Lafayette, Indiana 47907 (United States); Department of Physics, Purdue University, West Lafayette, Indiana 47907 (United States)

    2014-05-14T23:59:59.000Z

    We adapt time-dependent current density functional theory to allow for a fragment-based solution of the many-electron problem of molecules in the presence of time-dependent electric and magnetic fields. Regarding a molecule as a set of non-interacting subsystems that individually evolve under the influence of an auxiliary external electromagnetic vector-scalar potential pair, the partition 4-potential, we show that there are one-to-one mappings between this auxiliary potential, a sharply-defined set of fragment current densities, and the total current density of the system. The partition electromagnetic (EM) 4-potential is expressed in terms of the real EM 4-potential of the system and a gluing EM 4-potential that accounts for exchange-correlation effects and mutual interaction forces between fragments that are required to yield the correct electron dynamics. We prove the zero-force theorem for the fragmented system, establish a variational formulation in terms of action functionals, and provide a simple illustration for a charged particle in a ring.

  6. Upgrading of biorenewables to high energy density fuels

    SciTech Connect (OSTI)

    Gordon, John C [Los Alamos National Laboratory; Batista, Enrique R [Los Alamos National Laboratory; Chen, Weizhong [Los Alamos National Laboratory; Currier, Robert P [Los Alamos National Laboratory; Dirmyer, Matthew R [Los Alamos National Laboratory; John, Kevin D [Los Alamos National Laboratory; Kim, Jin K [Los Alamos National Laboratory; Keith, Jason [Los Alamos National Laboratory; Martin, Richard L [Los Alamos National Laboratory; Pierpont, Aaron W [Los Alamos National Laboratory; Silks Ill, L. A. "" Pete [Los Alamos National Laboratory; Smythe, Mathan C [Los Alamos National Laboratory; Sutton, Andrew D [Los Alamos National Laboratory; Taw, Felicia L [Los Alamos National Laboratory; Trovitch, Ryan J [Los Alamos National Laboratory; Vasudevan, Kalyan V [Los Alamos National Laboratory; Waidmann, Christopher R [Los Alamos National Laboratory; Wu, Ruilian [Los Alamos National Laboratory; Baker, R. Thomas [UNIV OF OTTAWWA; Schlaf, Marcel [UNIV OF GUELPH

    2010-12-07T23:59:59.000Z

    According to a recent report, lignocellulose is the most abundant renewable biological resource on earth, with an annual production of {approx} 200 x 10{sup 9} tons. Conversion of lignocellulosics derived from wood, agricultural wastes, and woody grasses into liquid fuels and value-added chemical feedstocks is an active area of research that has seen an explosion of effort due to the need to replace petroleum based sources. The carbohydrates D-glucose (C{sub 6}), L-arabinose (C{sub 5}), and D-xylose (C{sub 5}) are readily obtained from the hydrolysis of lignocellulose and constitute the most abundant renewable organic carbon source on the planet. Because they are naturally produced on such a large scale, these sugars have the greatest potential to displace petrochemical derived transportation fuel. Recent efforts in our laboratories aimed towards the production of high energy density transportation fuels from carbohydrates have been structured around the parameters of selective carbohydrate carbon chain extension chemistries, low reaction temperatures, and the desired use of water or neat substrate as the solvent. Some of our efforts in this regard will be presented.

  7. Predation, Competition, and Abiotic Disturbance: Population Dynamics of Small Mammals

    SciTech Connect (OSTI)

    Yunger, John A.; /Northern Illinois U. /Northern Illinois U.

    1996-01-01T23:59:59.000Z

    Predation and food availability have been implicated in annual non-cyclic fluctuations of vertebrate prey at mid-latitudes. The timing and magnitude of these factors are unclear due to a lack of large-scale field experiments, little attention to interactions, and a failure to closely link vertebrate predators with their prey. From October 1992 to January 1996, small mammal populations were censused on eight 0.6 ha plots at monthly intervals in a 32-ha prairie restoration at Fermi National Accelerator Laboratory, Illinois. Terrestrial vertebrate predators were excluded after July 1993 from four of the eight plots and canid diets monitored. Both terrestrial and avian vertebrate predators were excluded in March 1994. During 1993 small mammal densities (i.e., Microtus Pennsylvanicus, Peromyscus leucopus, and P. maniculatus) were relatively high. Following peak densities in late summer, Microtus numbers wer 2-3x greater on exclusion plots relative to controls due to preferential selection of Microtus by canids, as reflected in dits. Following an ice-storm and crash in small mammal numbers (particularly Microtus), vertebrate predator exclusion had no detectable effect on P. leucopus numbers, probably due to an abundance of alternative prey (i.e., Sylvilagus floridanus). Meadow vole numbers began to increase in Fall 1995, and a numerical effect of predator exclusion, similar to that in 1993, was observed. Predator exclusion had no detectable effect on the movements and spatial patterns of Microtus during 1993. There was a significant decrease in home range and a significant increase in home range overlap for P. leucopus on the predator exclusion plots. The change in spatial behavior may be due to interspecific competition with Microtus resulting from increased densities on exclusion plots. Thus, predators had an indirect effect on P. leucopus spatial patterns mediated through M. Pennsylvanicus. The role of food limitation was studied using natural and manipulative experiments. Unusually high acorn production in Fall 1994 resulted in increased P. leucopus numbers at one Fermilab site due to immigration since survivorship or reproduction were unaffected. A food supplementation experiment during October 1994-March 1995 induced a strong increase in P. leucopus numbers, due again to immigration, although reproduction also was advanced by two months.

  8. The Population Status The American Alligator

    E-Print Network [OSTI]

    Georgia, University of

    Carolina by Thomas M. Murphy A Publication of the Savannah River Plant National Environmental Research Park'S SAVANNAH RIVER PLANT NATIONAL ENVIRONMENT RESEARCH PARK Copies may be obtained from Savannah River Ecology Laboratory #12;- The Population Status of the American Alligator on the Savannah River Plant, South Carolina

  9. Populations of Galaxies Building a Galaxy

    E-Print Network [OSTI]

    Crenshaw, Michael

    1 Populations of Galaxies · Building a Galaxy · Stellar Luminosity Functions, Mass · Starburst galaxies, Ultraluminous Infrared Galaxies (ULIRGS) #12;2 Question: How would you build a synthetic metals. · Fill in an H-R (or color-magnitude) diagram and let it evolve. · Make a synthetic spectrum

  10. Galaxy populations from Deep ISO Surveys

    E-Print Network [OSTI]

    Seb Oliver

    2001-06-19T23:59:59.000Z

    I discuss some of the main extra-galactic field surveys which have been undertaken by the Infrared Space Observatory (ISO). I review the findings from the source counts analysies and then examine some of the more recent detailed investigations into the explicit nature of the populations that make up these source counts.

  11. Publications on Population Peer-Reviewed Articles

    E-Print Network [OSTI]

    Lopez-Carr, David

    - population nexus in the East African Horn: emerging degradation trends in rangeland and pastoral livelihood zones. Global Environmental Change 23 (6), 1525-1541. Davis J., López-Carr D. (2014) Migration) initiatives work? Evidence from WWF-sponsored projects in Africa and Asia.Proceedings of the International

  12. MULTIWAVELENGTH CONSTRAINTS ON PULSAR POPULATIONS IN THE GALACTIC CENTER

    SciTech Connect (OSTI)

    Wharton, R. S.; Chatterjee, S.; Cordes, J. M. [Department of Astronomy, Cornell University, Ithaca, NY 14853 (United States); Deneva, J. S. [Arecibo Observatory, HC3 Box 53995, Arecibo, PR 00612 (Puerto Rico); Lazio, T. J. W., E-mail: rwharton@astro.cornell.edu [Jet Propulsion Laboratory, California Institute of Technology, M/S 138-308, 4800 Oak Grove Dr., Pasadena, CA 91109 (United States)

    2012-07-10T23:59:59.000Z

    The detection of radio pulsars within the central few parsecs of the Galaxy would provide a unique probe of the gravitational and magneto-ionic environments in the Galactic center (GC) and, if close enough to Sgr A*, precise tests of general relativity in the strong-field regime. While it is difficult to find pulsars at radio wavelengths because of interstellar scattering, the payoff from detailed timing of pulsars in the GC warrants a concerted effort. To motivate pulsar surveys and help define search parameters for them, we constrain the pulsar number and spatial distribution using a wide range of multiwavelength measurements. These include the five known radio pulsars within 15' of Sgr A*, non-detections in high-frequency pulsar surveys of the central parsec, radio and gamma-ray measurements of diffuse emission, a catalog of radio point sources from an imaging survey, infrared observations of massive star populations in the central few parsecs, candidate pulsar wind nebulae in the inner 20 pc, and estimates of the core-collapse supernova rate based on X-ray measurements. We find that under current observational constraints, the inner parsec of the Galaxy could harbor as many as {approx}10{sup 3} active radio pulsars that are beamed toward Earth. Such a large population would distort the low-frequency measurements of both the intrinsic spectrum of Sgr A* and the free-free absorption along the line of sight of Sgr A*.

  13. population model Harald Rybka, Jason Wong, Jorge Rivas

    E-Print Network [OSTI]

    Yorke, James

    : food production = food consumption for a population of 8 billion consumption per capita is a constant

  14. On the mechanism of populating 3p levels of neon under pumping by a hard ioniser

    SciTech Connect (OSTI)

    Khasenov, M U [Fotonika LLC, ul. Utegen batyra 112, 050062 Almaty (Kazakhstan)

    2011-03-31T23:59:59.000Z

    The effect of quenching additives on the luminescence properties of helium - neon mixtures under pumping by {alpha} particles emitted from {sup 210}Po atoms is considered. It is concluded that, under excitation by a heavy charged particle, the population of the 3p'[1/2]{sub 0} level of neon is not related to the dissociative recombination of molecular ions. It is suggested that the most likely channels for populating the 3p level are the excitation transfer from metastable helium atoms to neon atoms and direct excitation of neon by nuclear particles and secondary electrons. (lasers and active media)

  15. Textured-surface quartz resonator fluid density and viscosity monitor

    DOE Patents [OSTI]

    Martin, Stephen J. (Albuquerque, NM); Wiczer, James J. (Albuquerque, NM); Cernosek, Richard W. (Albuquerque, NM); Frye, Gregory C. (Cedar Crest, NM); Gebert, Charles T. (Albuquerque, NM); Casaus, Leonard (Bernalillo, NM); Mitchell, Mary A. (Tijeras, NM)

    1998-08-25T23:59:59.000Z

    A pair of thickness-shear mode resonators, one smooth and one with a textured surface, allows fluid density and viscosity to be independently resolved. A textured surface, either randomly rough or regularly patterned, leads to trapping of liquid at the device surface. The synchronous motion of this trapped liquid with the oscillating device surface allows the device to weigh the liquid; this leads to an additional response that depends on liquid density. This additional response enables a pair of devices, one smooth and one textured, to independently resolve liquid density and viscosity; the difference in responses determines the density while the smooth device determines the density-viscosity product, and thus, the pair determines both density and viscosity.

  16. Density Functional Theory Calculations of Mass Transport in UO2

    SciTech Connect (OSTI)

    Andersson, Anders D. [Los Alamos National Laboratory; Dorado, Boris [CEA; Uberuaga, Blas P. [Los Alamos National Laboratory; Stanek, Christopher R. [Los Alamos National Laboratory

    2012-06-26T23:59:59.000Z

    In this talk we present results of density functional theory (DFT) calculations of U, O and fission gas diffusion in UO{sub 2}. These processes all impact nuclear fuel performance. For example, the formation and retention of fission gas bubbles induce fuel swelling, which leads to mechanical interaction with the clad thereby increasing the probability for clad breach. Alternatively, fission gas can be released from the fuel to the plenum, which increases the pressure on the clad walls and decreases the gap thermal conductivity. The evolution of fuel microstructure features is strongly coupled to diffusion of U vacancies. Since both U and fission gas transport rates vary strongly with the O stoichiometry, it is also important to understand O diffusion. In order to better understand bulk Xe behavior in UO{sub 2{+-}x} we first calculate the relevant activation energies using DFT techniques. By analyzing a combination of Xe solution thermodynamics, migration barriers and the interaction of dissolved Xe atoms with U, we demonstrate that Xe diffusion predominantly occurs via a vacancy-mediated mechanism. Since Xe transport is closely related to diffusion of U vacancies, we have also studied the activation energy for this process. In order to explain the low value of 2.4 eV found for U migration from independent damage experiments (not thermal equilibrium) the presence of vacancy clusters must be included in the analysis. Next we investigate species transport on the (111) UO{sub 2} surface, which is motivated by the formation of small voids partially filled with fission gas atoms (bubbles) in UO{sub 2} under irradiation. Surface diffusion could be the rate-limiting step for diffusion of such bubbles, which is an alternative mechanism for mass transport in these materials. As expected, the activation energy for surface diffusion is significantly lower than for bulk transport. These results are further discussed in terms of engineering-scale fission gas release models. Finally, oxidation of UO{sub 2} and the importance of cluster formation for understanding thermodynamic and kinetic properties of UO{sub 2+x} are investigated.

  17. Activity report

    SciTech Connect (OSTI)

    Yu, S W

    2008-08-11T23:59:59.000Z

    This report is aimed to show the author's activities to support the LDRD. The title is 'Investigation of the Double-C Behavior in the Pu-Ga Time-Temperature-Transformation Diagram' The sections are: (1) Sample Holder Test; (2) Calculation of x-ray diffraction patterns; (3) Literature search and preparing publications; (4) Tasks Required for APS Experiments; and (5) Communications.

  18. Method for measuring the density of lightweight materials

    DOE Patents [OSTI]

    Snow, Samuel G. (Oak Ridge, TN); Giacomelli, Edward J. (Knoxville, TN)

    1980-01-01T23:59:59.000Z

    This invention relates to a nondestructive method for measuring the density of articles composed of elements having a low atomic number such as plastic and carbon composites. The measurement is accomplished by striking the article with a collimated beam of X radiation, simultaneously monitoring the radiation scattered and the radiation transmitted by the article, then relating the ratio of the radiation scattered to the radiation transmitted with the density of the article. The above method is insensitive to all variables except density.

  19. Crystallization of polyethylene by modified weighted density approximation(MWDA)

    E-Print Network [OSTI]

    Razeghizadeh, Alireza; Lavafpour, Farhad

    2015-01-01T23:59:59.000Z

    In this article, we use the modified weighted density approximation to study the crystallization of polyethylene. We also use a direct correlation function of polyethylene based on RISM theory. The free energy of a polyethylene is calculated using density functional theory. The crystallization and solid and liquid density are calculated and finally compared with the prism simulation and experimental results. That shown the result obtained by MWDA is in better agreement, compared with the experimental result than the prism.

  20. Crystallization of polyethylene by modified weighted density approximation(MWDA)

    E-Print Network [OSTI]

    Alireza Razeghizadeh; Vahdat Rafee; Farhad Lavafpour

    2015-02-07T23:59:59.000Z

    In this article, we use the modified weighted density approximation to study the crystallization of polyethylene. We also use a direct correlation function of polyethylene based on RISM theory. The free energy of a polyethylene is calculated using density functional theory. The crystallization and solid and liquid density are calculated and finally compared with the prism simulation and experimental results. That shown the result obtained by MWDA is in better agreement, compared with the experimental result than the prism.

  1. Particle-Number Projection and the Density Functional Theory

    E-Print Network [OSTI]

    J. Dobaczewski; M. V. Stoitsov; W. Nazarewicz; P. -G. Reinhard

    2007-08-03T23:59:59.000Z

    In the framework of the Density Functional Theory for superconductors, we study the restoration of the particle number symmetry by means of the projection technique. Conceptual problems are outlined and numerical difficulties are discussed. Both are related to the fact that neither the many-body Hamiltonian nor the wave function of the system appear explicitly in the Density Functional Theory. Similar obstacles are encountered in self-consistent theories utilizing density-dependent effective interactions.

  2. Unambiguous exchange-correlation energy density Kieron Burke,a)

    E-Print Network [OSTI]

    Burke, Kieron

    density approximation LDA , the conventional form is eXC unif (r) , the exchange-correlation energy the following definition of an energy density: eXC wave fn. r d3 r P r,r r r 2 r r 1 2 2 r,r s r,r r r , 2 whereUnambiguous exchange-correlation energy density Kieron Burke,a) Federico G. Cruz, and Kin-Chung Lam

  3. Nuclear symmetry energy at subnormal densities from measured nuclear masses

    E-Print Network [OSTI]

    Min Liu; Ning Wang; Zhuxia Li; Fengshou Zhang

    2010-11-17T23:59:59.000Z

    The symmetry energy coefficients for nuclei with mass number A=20~250 are extracted from more than 2000 measured nuclear masses. With the semi-empirical connection between the symmetry energy coefficients of finite nuclei and the nuclear symmetry energy at reference densities, we investigate the density dependence of symmetry energy of nuclear matter at subnormal densities. The obtained results are compared with those extracted from other methods.

  4. Computing the moments of the neutron population using deterministic neutron transport

    SciTech Connect (OSTI)

    Fichtl, E. D.; Baker, R. S. [Los Alamos National Laboratory, Computational Physics and Methods, CCS-2, PO Box 1663, Los Alamos, NM, 87544 (United States)

    2013-07-01T23:59:59.000Z

    It is important to treat the inherent stochasticity of the fission process in systems where the behavior of the system is stochastic. This occurs when there are few neutrons in the system, or when the neutron source is weak. In order to characterize such systems, the capability to compute the first four moments of the neutron population distribution has been added to the deterministic neutral particle transport code, PARTISN. The moments are then fitted to probability density functions from the Pearson family. PARTISN is compared against MCNP6, with which it agrees well. (authors)

  5. Dynamics of ion acoustic double layers in a magnetized two-population electrons plasma

    SciTech Connect (OSTI)

    Shahmansouri, M. [Department of Physics, Faculty of Science, Arak University, Arak 38156-8-8349 (Iran, Islamic Republic of)] [Department of Physics, Faculty of Science, Arak University, Arak 38156-8-8349 (Iran, Islamic Republic of)

    2013-10-15T23:59:59.000Z

    The obliquely propagating ion acoustic (IA) double-layers are investigated in a magnetized two population electron plasmas. The extended Kortewegde Vries equation is derived by using the reductive perturbation technique. The effect of obliqueness (l{sub z}) and magnitude of the external magnetic field (?{sub ci}), as well as the electron number density (?) on the double-layer profile, is studied, and then the ranges of parameters for which the double-layers exist are investigated in detail. We found that the combined effects of l{sub z}, ?{sub ci}, and ? significantly modify the basic properties (viz. amplitude and width) of the IA double-layers.

  6. SciTech Connect: Chiral dynamics and peripheral transverse densities

    Office of Scientific and Technical Information (OSTI)

    in terms of frame-independent charge and magnetization densities in transverse space. This formulation allows one to identify the chiral components of nucleon structure as...

  7. ATMOSPHERIC DENSITY ESTIMATION USING SATELLITE PRECISION ORBIT EPHEMERIDES

    E-Print Network [OSTI]

    Arudra, Anoop Kumar

    2011-04-22T23:59:59.000Z

    ..................................................................................... 92 4.5.2 Density and Ballistic Coefficient Correlated Half-life Variation. ............................. 92 5 SUMMARY, CONCLUSIONS AND FUTURE WORK .............................. 93 5.1 Summary...

  8. Engineering Density of States of Earth Abundant Semiconductors...

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

    of States of Earth Abundant Semiconductors for Enhanced Thermoelectric Power Factor Engineering Density of States of Earth Abundant Semiconductors for Enhanced Thermoelectric...

  9. Relationship of Quantum Entanglement to Density Functional Theory

    E-Print Network [OSTI]

    A. K. Rajagopal; R. W. Rendell

    2005-12-13T23:59:59.000Z

    The maximum von Neumann entropy principle subject to given constraints of mean values of some physical observables determines the density matrix. Similarly the stationary action principle in the case of time-dependent (dissipative) situations under similar constraints yields the density matrix. The free energy and measures of entanglement are expressed in terms of such a density matrix and thus define respective functionals of the mean values. In the light of several model calculations, it is found that the density matrix contains information about both quantum entanglement and phase transitions even though there may not be any direct relationship implied by one on the other.

  10. Time-dependent density-functional theory for open systems

    E-Print Network [OSTI]

    Xiao Zheng; Fan Wang; Chi Yung Yam; Yan Mo; GuanHua Chen

    2007-02-27T23:59:59.000Z

    By introducing the self-energy density functionals for the dissipative interactions between the reduced system and its environment, we develop a time-dependent density-functional theory formalism based on an equation of motion for the Kohn-Sham reduced single-electron density matrix of the reduced system. Two approximate schemes are proposed for the self-energy density functionals, the complete second order approximation and the wide-band limit approximation. A numerical method based on the wide-band limit approximation is subsequently developed and implemented to simulate the steady and transient current through various realistic molecular devices. Simulation results are presented and discussed.

  11. A New Computational Approach to Density Estimation with ...

    E-Print Network [OSTI]

    2003-12-19T23:59:59.000Z

    which would be reasonably imposed on the density function. AIC (Akaike ..... The book [7] is a recent textbook in which theory, algorithms and applications are. 6...

  12. TEMPORAL VARIATIONS OF FRACTURE DIRECTIONS AND FRACTURE DENSITIES...

    Open Energy Info (EERE)

    TEMPORAL VARIATIONS OF FRACTURE DIRECTIONS AND FRACTURE DENSITIES IN THE COSO GEOTHERMAL FIELD FROM ANALYSES OF SHEAR-WAVE SPLITTING Jump to: navigation, search OpenEI Reference...

  13. A Comprehensive Study Of Fracture Patterns And Densities In The...

    Open Energy Info (EERE)

    Study Of Fracture Patterns And Densities In The Geysers Geothermal Reservoir Using Microearthquake Shear-Wave Splitting Tomography Jump to: navigation, search OpenEI Reference...

  14. Developing a Lower Cost and Higher Energy Density Alternative...

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

    for Advanced Batteries ADVANCED MANUFACTURING OFFICE Developing a Lower Cost and Higher Energy Density Alternative to Lithium-Ion Batteries Introduction As the world moves toward...

  15. Constraints on the density dependence of the symmetry energy

    E-Print Network [OSTI]

    M. B. Tsang; Yingxun Zhang; P. Danielewicz; M. Famiano; Zhuxia Li; W. G. Lynch; A. W. Steiner

    2008-11-19T23:59:59.000Z

    Collisions involving 112Sn and 124Sn nuclei have been simulated with the improved Quantum Molecular Dynamics transport model. The results of the calculations reproduce isospin diffusion data from two different observables and the ratios of neutron and proton spectra. By comparing these data to calculations performed over a range of symmetry energies at saturation density and different representations of the density dependence of the symmetry energy, constraints on the density dependence of the symmetry energy at sub-normal density are obtained. Results from present work are compared to constraints put forward in other recent analysis.

  16. Constraints on the Density Dependence of the Symmetry Energy

    SciTech Connect (OSTI)

    Tsang, M. B.; Danielewicz, P.; Lynch, W. G.; Steiner, A. W. [Joint Institute of Nuclear Astrophysics and National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824 (United States); Physics and Astronomy Department, Michigan State University, East Lansing, Michigan 48824 (United States); Zhang Yingxun [Joint Institute of Nuclear Astrophysics and National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824 (United States); China Institute of Atomic Energy, P.O. Box 275 (18), Beijing 102413 (China); Famiano, M. [Physics Department, Western Michigan University, Kalamazoo, Michigan 49008 (United States); Li, Zhuxia [China Institute of Atomic Energy, P.O. Box 275 (18), Beijing 102413 (China)

    2009-03-27T23:59:59.000Z

    Collisions involving {sup 112}Sn and {sup 124}Sn nuclei have been simulated with the improved quantum molecular dynamics transport model. The results of the calculations reproduce isospin diffusion data from two different observables and the ratios of neutron and proton spectra. By comparing these data to calculations performed over a range of symmetry energies at saturation density and different representations of the density dependence of the symmetry energy, constraints on the density dependence of the symmetry energy at subnormal density are obtained. The results from the present work are compared to constraints put forward in other recent analyses.

  17. Constraints on the density dependence of the symmetry energy

    E-Print Network [OSTI]

    Tsang, M B; Danielewicz, P; Famiano, M; Li, Zhuxia; Lynch, W G; Steiner, A W

    2008-01-01T23:59:59.000Z

    Collisions involving 112Sn and 124Sn nuclei have been simulated with the improved Quantum Molecular Dynamics transport model. The results of the calculations reproduce isospin diffusion data from two different observables and the ratios of neutron and proton spectra. By comparing these data to calculations performed over a range of symmetry energies at saturation density and different representations of the density dependence of the symmetry energy, constraints on the density dependence of the symmetry energy at sub-normal density are obtained. Results from present work are compared to constraints put forward in other recent analysis.

  18. Innovative High Energy Density Capacitor Design Offers Potential...

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

    like TroyCap's High Density Energy Nanolaminate Capacitor (HEDCAP) that may offer new clean energy applications to meet the nation's strategic energy goals and secure...

  19. Vehicle Technologies Office Merit Review 2014: High Energy Density...

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

    Vehicle Technologies Office Merit Review 2014: High Energy Density Li-ion Cells for EV's Based on Novel, High Voltage Cathode Material Systems Vehicle Technologies Office Merit...

  20. COLD BUBBLE FORMATION DURING TOKAMAK DENSITY LIMIT DISRUPTIONS

    E-Print Network [OSTI]

    Howard, John

    COLD BUBBLE FORMATION DURING TOKAMAK DENSITY LIMIT DISRUPTIONS J. HOWARD, M. PERSSON* Plasma Research Laboratory, Research School of Physical Sciences, Australian National University, Canberra

  1. Lesson 1: Data Types and Watershed Populations In this first lesson, you will discover some information about each of the two watersheds

    E-Print Network [OSTI]

    of people per block. This is a good summary of how many people are in the watershed and where they live the condition of the watersheds regarding how people are currently living on and using the land. We will use Arc watershed (2000 census), the population density (average number of people per hectare), and to visualize how

  2. Accurate and systematically improvable density functional theory embedding for correlated wavefunctions

    SciTech Connect (OSTI)

    Goodpaster, Jason D.; Barnes, Taylor A.; Miller, Thomas F., E-mail: tfm@caltech.edu [Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125 (United States); Manby, Frederick R., E-mail: fred.manby@bristol.ac.uk [Centre for Computational Chemistry, School of Chemistry, University of Bristol, Bristol BS8 ITS (United Kingdom)

    2014-05-14T23:59:59.000Z

    We analyze the sources of error in quantum embedding calculations in which an active subsystem is treated using wavefunction methods, and the remainder using density functional theory. We show that the embedding potential felt by the electrons in the active subsystem makes only a small contribution to the error of the method, whereas the error in the nonadditive exchange-correlation energy dominates. We test an MP2 correction for this term and demonstrate that the corrected embedding scheme accurately reproduces wavefunction calculations for a series of chemical reactions. Our projector-based embedding method uses localized occupied orbitals to partition the system; as with other local correlation methods, abrupt changes in the character of the localized orbitals along a reaction coordinate can lead to discontinuities in the embedded energy, but we show that these discontinuities are small and can be systematically reduced by increasing the size of the active region. Convergence of reaction energies with respect to the size of the active subsystem is shown to be rapid for all cases where the density functional treatment is able to capture the polarization of the environment, even in conjugated systems, and even when the partition cuts across a double bond.

  3. Peroxisome Proliferator-activated Receptor / Regulates Very Low Density Lipoprotein Production and Catabolism in

    E-Print Network [OSTI]

    Omiecinski, Curtis

    in PPAR -null mice on a HF diet, both proteins of which have recently been shown to inhibit lipoprotein and Catabolism in Mice on a Western Diet* Received for publication, November 24, 2003, and in revised form of mice lacking a func- tional PPAR receptor were determined. PPAR -null mice maintained on either normal

  4. ACTIVE CATHODES FOR SUPER-HIGH POWER DENSITY SOLID OXIDE FUEL CELLS THROUGH SPACE CHARGE EFFECTS

    SciTech Connect (OSTI)

    Anil V. Virkar

    2004-05-17T23:59:59.000Z

    This report summarizes the work done during the sixth quarter of the project. Effort was directed in three areas: (1) Further development of the model on the role of connectivity on ionic conductivity of porous bodies, including the role of grain boundaries and space charge region. (2) Calculation of the effect of space charge and morphology of porous bodies on the effective charge transfer resistance of porous composite cathodes. (3) The investigation of the three electrode system for the measurement of cathodic polarization using amperometric sensors.

  5. E-Print Network 3.0 - activity mammographic density Sample Search...

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

    Sciences ; Engineering 82 T. J. Brukilacchio, Ph.D. Thesis 2003 A DIFFUSE OPTICAL TOMOGRAPHY SYSTEM COMBINED Summary: , mammographic specificity is known to be limited 2....

  6. Copper nanocrystal modified activated carbon for supercapacitors with enhanced volumetric energy and power density

    E-Print Network [OSTI]

    Cao, Guozhong

    capacitors (EDLCs) have evoked wide interest in recent years due to their ability to supply high power of EDLCs is based on the quick formation of a double layer of surface charges and counter materials for EDLCs should have large surface area to accumulate a large amount of charges, and a size

  7. Sulfurized activated carbon for high energy density supercapacitors Yunxia Huang a,b

    E-Print Network [OSTI]

    Cao, Guozhong

    electric double layer capacitors (EDLCs) or pseudo-capacitors. The former is based on the accumulation

  8. The interactive effects of pH, surface tension, and solution density for flotation systems for separation of equivalent-density materials: separation of ABS from HIPS

    SciTech Connect (OSTI)

    Karvelas, D.E.; Jody, B.J.; Pomykala, J.A.; Daniels, E.J.

    1996-07-01T23:59:59.000Z

    This paper presents the results of research being conducted at Argonne National Laboratory, to develop a cost-effective and environmentally acceptable process for the separation of high-value plastics from discarded household appliances. The process under development has separated high-purity (greater than 99.5%) acrylonitrile-butadiene-styrene (ABS) and high-impact polystyrene (HIPS) from commingled plastics generated by appliance-shredding and metal recovery operations. Plastics of similar densities, such as ABS and HIPS are further separated by using a chemical solution. By controlling the surface tension, the density and the temperature of the chemical solution, we are able to selectively float/separate plastics that have equivalent densities. In laboratory-scale tests, this technique has proven highly effective in recovering high-purity plastics materials from discarded household appliances and other obsolete durable goods. A pilot plant is under construction to demonstrate and assess the technical and economic performance of this process. In this paper, we examine the technical and economic issues that affect the recovery and separation of plastics and provide an update on Argonne`s plastics separation research and development activities.

  9. Population inversion in a magnetized hydrogen plasma expansion as a consequence of the molecular mutual neutralization process

    SciTech Connect (OSTI)

    Harskamp, W. E. N. van; Brouwer, C. M.; Schram, D. C.; Sanden, M. C. M. van de; Engeln, R. [Department of Applied Physics, Eindhoven University of Technology, P.O. Box 513, NL-5600 MB Eindhoven (Netherlands)

    2011-03-15T23:59:59.000Z

    A weakly magnetized expanding hydrogen plasma, created by a cascaded arc, was investigated using optical emission spectroscopy. The emission of the expanding plasma is dominated by H{sub {alpha}} emission in the first part of the plasma expansion, after which a sharp transition to a blue afterglow is observed. The position of this sharp transition along the expansion axis depends on the magnetic field strength. The blue afterglow emission is associated with population inversion of the electronically excited atomic hydrogen states n=4-6 with respect to n=3. By comparing the measured densities with the densities using an atomic collisional radiative model, we conclude that atomic recombination processes cannot account for the large population densities observed. Therefore, molecular processes must be important for the formation of excited states and for the occurrence of population inversion. This is further corroborated at the transition from red to blue, where a hollow profile of the excited states n=4-6 in the radial direction is observed. This hollow profile is explained by the molecular mutual neutralization process of H{sub 2}{sup +} with H{sup -}, which has a maximum production for excited atomic hydrogen 1-2 cm outside the plasma center.

  10. Surface properties of liquid mercury: a comparison of density-dependent and density-independent force fields

    E-Print Network [OSTI]

    A. Iakovlev; D. Bedrov; M. Mller

    2014-12-08T23:59:59.000Z

    The surface properties of liquid mercury (Hg) at a temperature of 293 K are investigated by classical Molecular Dynamics simulation using density-independent (DI) and density-dependent (DD) force fields. The latter force fields were introduced to improve the description of surface properties. Both force fields yield lower values of the surface tension in comparison to experimental data. Moreover, the density-dependent force field results in an anomalous thermodynamic behavior. These findings are rationalized by liquid-state theory. An optimized, density-independent force field is proposed that yields a higher surface tension and, at the same time, provides an accurate description of the liquid-vapor coexistence.

  11. Power-law tails in probability density functions of molecular cloud column density

    E-Print Network [OSTI]

    Brunt, Chris

    2015-01-01T23:59:59.000Z

    Power-law tails are often seen in probability density functions (PDFs) of molecular cloud column densities, and have been attributed to the effect of gravity. We show that extinction PDFs of a sample of five molecular clouds obtained at a few tenths of a parsec resolution, probing extinctions up to A$_{{\\mathrm{V}}}$ $\\sim$ 10 magnitudes, are very well described by lognormal functions provided that the field selection is tightly constrained to the cold, molecular zone and that noise and foreground contamination are appropriately accounted for. In general, field selections that incorporate warm, diffuse material in addition to the cold, molecular material will display apparent core+tail PDFs. The apparent tail, however, is best understood as the high extinction part of a lognormal PDF arising from the cold, molecular part of the cloud. We also describe the effects of noise and foreground/background contamination on the PDF structure, and show that these can, if not appropriately accounted for, induce spurious ...

  12. Evolutionary optimization of rotational population transfer

    SciTech Connect (OSTI)

    Rouzee, Arnaud; Vrakking, Marc J. J. [FOM Institute for Atomic and Molecular Physics (AMOLF), Science Park 104, NL-1098 XG Amsterdam (Netherlands); Max Born Institut, Max Born Strasse 2A, D-12489, Berlin (Germany); Ghafur, Omair; Gijsbertsen, Arjan [FOM Institute for Atomic and Molecular Physics (AMOLF), Science Park 104, NL-1098 XG Amsterdam (Netherlands); Vidma, Konstantin; Meijer, Afric; Zande, Wim J. van der; Parker, David [Institute of Molecules and Materials, Radboud University Nijmegen, Toernooiveld 1, NL-6500 GL Nijmegen (Netherlands); Shir, Ofer M.; Baeck, Thomas [Leiden Institute of Advanced Computer Science (LIACS), Niels Bohrweg 1, NL-2333 CA Leiden (Netherlands)

    2011-09-15T23:59:59.000Z

    We present experimental and numerical studies on control of rotational population transfer of NO(J=1/2) molecules to higher rotational states. We are able to transfer 57% of the population to the J=5/2 state and 46% to J=9/2, in good agreement with quantum mechanical simulations. The optimal pulse shapes are composed of pulse sequences with delays corresponding to the beat frequencies of states on the rotational ladder. The evolutionary algorithm is limited by experimental constraints such as volume averaging and the finite laser intensity used, the latter to circumvent ionization. Without these constraints, near-perfect control (>98%) is possible. In addition, we show that downward control, moving molecules from high to low rotational states, is also possible.

  13. Federal Biomass Activities

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

    and Budget Federal Biomass Activities Federal Biomass Activities Biopower Biopower Biofuels Biofuels Bioproducts Bioproducts Federal Biomass Activities Federal Biomass...

  14. Population dynamics of the Concho water snake

    E-Print Network [OSTI]

    Mueller, James Michael

    1990-01-01T23:59:59.000Z

    the upper Colorado and Concho river systems of central Texas. It is 1 of 2 subspecies, the other being the Brazos water snake (Nerodia harteri harteri) which occurs in the Brazos river system of north-central Texas, Together they comprise the only species..., reproductive potential, mortality, and movements. williams predicted that habitat degradation resulting from the creation of Spence Reservoir, 2 km above his study site, would be detrimental to the Concho water snake population. Since the impoundment...

  15. WANDERING STARS: AN ORIGIN OF ESCAPED POPULATIONS

    SciTech Connect (OSTI)

    Teyssier, Maureen; Johnston, Kathryn V. [Department of Astronomy, Columbia University, Pupin Physics Laboratory, 550 West 120th Street, New York, NY 10027 (United States); Shara, Michael M. [American Museum of Natural History, 79th Street and Central Park West, New York, NY 10024-5192 (United States)

    2009-12-10T23:59:59.000Z

    We demonstrate that stars beyond the virial radii of galaxies may be generated by the gravitational impulse received by a satellite as it passes through the pericenter of its orbit around its parent. These stars may become energetically unbound (escaped stars), or may travel to further than a few virial radii for longer than a few Gyr, but still remain energetically bound to the system (wandering stars). Larger satellites (10%-100% the mass of the parent), and satellites on more radial orbits are responsible for the majority of this ejected population. Wandering stars could be observable on Mpc scales via classical novae, and on 100 Mpc scales via Type Ia supernova. The existence of such stars would imply a corresponding population of barely bound, old, high-velocity stars orbiting the Milky Way, generated by the same physical mechanism during the Galaxy's formation epoch. Sizes and properties of these combined populations should place some constraints on the orbits and masses of the progenitor objects from which they came, providing insight into the merging histories of galaxies in general and the Milky Way in particular.

  16. Note: A real-time beam current density meter

    SciTech Connect (OSTI)

    Liu Junliang; Yu Deyang; Ruan Fangfang; Xue Yingli; Wang Wei [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China)

    2013-03-15T23:59:59.000Z

    We have developed a real-time beam current density meter for charged particle beams. It measures the mean current density by collimating a uniform and large diameter primary beam. The suppression of the secondary electrons and the deflection of the beam were simulated, and it was tested with a 105 keV Ar{sup 7+} ion beam.

  17. THERMAL CONDUCTIVITY OF HEMP CONCRETES: VARIATION WITH FORMULATION, DENSITY AND

    E-Print Network [OSTI]

    envelope and on the performance of systems. This behaviour is related to hygric and thermal propertiesTHERMAL CONDUCTIVITY OF HEMP CONCRETES: VARIATION WITH FORMULATION, DENSITY AND WATER CONTENT of formulation, density and water content on the thermal conductivity of hemp concretes. The investigations

  18. The MSW effect in a fluctuating matter density

    E-Print Network [OSTI]

    A. B. Balantekin; J. M. Fetter; F. N. Loreti

    1996-04-11T23:59:59.000Z

    We consider the effect on matter-enhanced neutrino flavor transformation of a randomly fluctuating, delta-correlated matter density. The fluctuations will produce a distribution of neutrino survival probabilities. We find the mean and variance of the distribution for the case of solar neutrinos, and discuss the possibility of placing a limit on solar density fluctuations using neutrino data.

  19. THE STAR FORMATION LAW AT LOW SURFACE DENSITY

    SciTech Connect (OSTI)

    Wyder, Ted K.; Martin, D. Christopher; Barlow, Tom A.; Foster, Karl; Friedman, Peter G.; Morrissey, Patrick; Neill, James D. [California Institute of Technology, MC 278-17, 1200 E. California Blvd., Pasadena, CA 91125 (United States); Neff, Susan G. [Laboratory for Astronomy and Solar Physics, NASA Goddard Space Flight Center, Greenbelt, MD, 20771 (United States); Schiminovich, David [Department of Astronomy, Columbia University, New York, NY 10027 (United States); Seibert, Mark; Madore, Barry F. [Observatories of the Carnegie Institution of Washington, 813 Santa Barbara Street, Pasadena, CA 91101 (United States); Bianchi, Luciana [Center for Astrophysical Sciences, Johns Hopkins University, 3400 N. Charles Street, Baltimore, MD 21218 (United States); Donas, Jose; Milliard, Bruno [Laboratoire d'Astrophysique de Marseille, BP 8, Traverse du Siphon, 13376 Marseille Cedex 12 (France); Heckman, Timothy M.; Szalay, Alex S. [Department of Physics and Astronomy, Johns Hopkins University, Homewood Campus, Baltimore, MD 21218 (United States); Lee, Young-Wook; Yi, Sukyoung K. [Center for Space Astrophysics, Yonsei University, Seoul 120-749 (Korea, Republic of); Rich, R. Michael [Department of Physics and Astronomy, University of California, Los Angeles, CA 90095 (United States)

    2009-05-10T23:59:59.000Z

    We investigate the nature of the star formation law at low gas surface densities using a sample of 19 low surface brightness (LSB) galaxies with existing H I maps in the literature, UV imaging from the Galaxy Evolution Explorer satellite, and optical images from the Sloan Digital Sky Survey. All of the LSB galaxies have (NUV - r) colors similar to those for higher surface brightness star-forming galaxies of similar luminosity indicating that their average star formation histories are not very different. Based upon four LSB galaxies with both UV and far-infrared (FIR) data, we find FIR/UV ratios significantly less than 1, implying low amounts of internal UV extinction in LSB galaxies. We use the UV images and H I maps to measure the star formation rate (SFR) and hydrogen gas surface density within the same region for all the galaxies. The LSB galaxy star formation rate surface densities lie below the extrapolation of the power law fit to the SFR surface density as a function of the total gas density for higher surface brightness galaxies. Although there is more scatter, the LSB galaxies also lie below a second version of the star formation law in which the SFR surface density is correlated with the gas density divided by the orbital time in the disk. The downturn seen in both star formation laws is consistent with theoretical models that predict lower star formation efficiencies in LSB galaxies due to the declining molecular fraction with decreasing density.

  20. High density Integrated Optoelectronic Circuits for High Speed Photonic Microsystems

    E-Print Network [OSTI]

    Kouroupetroglou, Georgios

    High density Integrated Optoelectronic Circuits for High Speed Photonic Microsystems K. Minoglou.minoglou@imel.demorkitos.gr Abstract. The study of high density integrated optoelectronic circuits involves the development of hybrid integration technologies and the generation of models for the optoelectronic devices. To meet these goals

  1. Relativistic plasma nanophotonics for ultrahigh energy density physics

    E-Print Network [OSTI]

    Rocca, Jorge J.

    Relativistic plasma nanophotonics for ultrahigh energy density physics Michael A. Purvis1 volumetrically heat dense matter into a new ultrahot plasma regime. Electron densities nearly 100 times greater) and gigabar press- ures only exceeded in the central hot spot of highly compressed thermonuclear fusion

  2. Irradiation effects in high-density polyethylene Jussi Polvia

    E-Print Network [OSTI]

    Nordlund, Kai

    Irradiation effects in high-density polyethylene Jussi Polvia , Kai Nordlunda a simulations, we have studied the irradiation effects in high density polyethylene. We determined the threshold energy for creating defects in the polyethylene lattice as a function of the incident angle. We found

  3. Complex structure of electron and density functional theory

    E-Print Network [OSTI]

    K. Koshelev

    2013-01-08T23:59:59.000Z

    Effective model for electron as two particle system is considered. The first particle in the system is chargeless mass of electron. The second one is massless charge of electron. Based on this model it is shown that density of energy for the particle is proportional to the probability density and the following formula stands $\\rho_E(x)=mc^2\\rho(x)$.

  4. Density functional theory for self-bound systems

    E-Print Network [OSTI]

    Nir Barnea

    2007-11-06T23:59:59.000Z

    The density functional theory is extended to account for self-bound systems. To this end the Hohenberg-Kohn theorem is formulated for the intrinsic density and a Kohn-Sham like procedure for an $N$--body system is derived using the adiabatic approximation to account for the center of mass motion.

  5. Connections on statistical manifolds of density operators by geometry of

    E-Print Network [OSTI]

    Isola, Tommaso

    of statistical manifolds, that is of manifolds whose points can be identified with density functions with respect to a certain measure µ. The classical references for the theory can be found in the books [1, 2, 4Connections on statistical manifolds of density operators by geometry of noncommutative Lp -spaces

  6. Envelope of Fracture Density Dragana Todorovic-Marinic*

    E-Print Network [OSTI]

    Santos, Juan

    Envelope of Fracture Density Dragana Todorovic-Marinic* Veritas DGC Ltd., Calgary, Alberta, Canada that interpretation of fractures can be improved by using the envelope of the fracture density. It has been shown that open, fluid (or gas) filled fractures can be identified through the use of the AVAZ method (Gray et. al

  7. MARKOV CHAIN APPROXIMATIONS FOR TRANSITION DENSITIES OF LEVY PROCESSES

    E-Print Network [OSTI]

    MARKOV CHAIN APPROXIMATIONS FOR TRANSITION DENSITIES OF L´EVY PROCESSES ALEKSANDAR MIJATOVI for the existence of transition densities of X, we establish sharp convergence rates of the normalised probability class with applications in diverse areas such as mathematical finance, risk management, insurance

  8. Locating a Recycling Center: The General Density Case Jannett Highfill

    E-Print Network [OSTI]

    Mou, Libin

    Locating a Recycling Center: The General Density Case Jannett Highfill Department of Economics) 677-3374. #12;2 Locating a Recycling Center: The General Density Case Abstract: The present paper considers a municipality that has a landfill (fixed in location) and plans to optimally locate a "recycling

  9. CONCRETE OPTIMISATION WITH REGARD TO PACKING DENSITY AND RHEOLOGY

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    /organizers): .............. Keywords: packing density, rheology, grading curve, optimisation, self-compacting concrete, roller-compactedCONCRETE OPTIMISATION WITH REGARD TO PACKING DENSITY AND RHEOLOGY François de Larrard LCPC Centre concrete. Author contacts Authors E-Mail Fax Postal address LCPC Centre de Nantes François de Larrard

  10. Density-Enthalpy Phase Diagram 0D Boiler Simulation

    E-Print Network [OSTI]

    Vuik, Kees

    Diagram 0D Boiler Simulation Finite Element Method Further Research Mass and Heat balances V d dt = i - eDensity-Enthalpy Phase Diagram 0D Boiler Simulation Finite Element Method Further Research Finite Transitions #12;Density-Enthalpy Phase Diagram 0D Boiler Simulation Finite Element Method Further Research

  11. Experimental investigation on the temperature dependence of the nuclear level density parameter

    E-Print Network [OSTI]

    Dey, Balaram; Bhattacharya, Srijit; Banerjee, K; Hung, N Quang; Dang, N Dinh; Mondal, Debasish; Mukhopadhyay, S; Pal, Surajit; De, A; Banerjee, S R

    2015-01-01T23:59:59.000Z

    The effect of temperature (T) and angular momentum (J) on the inverse level density parameter (k) has been studied by populating the compound nucleus $^{97}$Tc in the reaction $^{4}$He + $^{93}$Nb at four incident beam energies of 28, 35, 42 and 50 MeV. For all the four energies, the value of k decreases with increasing J. The T dependence of k has been compared for two angular momentum windows with different theoretical predictions as well as with FTBCS1 calculation which takes into account the quasiparticle-number fluctuations in the pairing field. Interestingly, the experimental data are in good agreement with the theoretical calculations at higher J but deviate from all the calculations at lower J.

  12. Energy Aware Self-Organizing Density Management in Wireless Sensor Networks

    E-Print Network [OSTI]

    Merrer, Erwan Le; Kermarrec, Anne-Marie; Viana, Aline; Bertier, Marin

    2008-01-01T23:59:59.000Z

    Energy consumption is the most important factor that determines sensor node lifetime. The optimization of wireless sensor network lifetime targets not only the reduction of energy consumption of a single sensor node but also the extension of the entire network lifetime. We propose a simple and adaptive energy-conserving topology management scheme, called SAND (Self-Organizing Active Node Density). SAND is fully decentralized and relies on a distributed probing approach and on the redundancy resolution of sensors for energy optimizations, while preserving the data forwarding and sensing capabilities of the network. We present the SAND's algorithm, its analysis of convergence, and simulation results. Simulation results show that, though slightly increasing path lengths from sensor to sink nodes, the proposed scheme improves significantly the network lifetime for different neighborhood densities degrees, while preserving both sensing and routing fidelity.

  13. Symmetry Energy as a Function of Density and Mass

    E-Print Network [OSTI]

    Pawel Danielewicz; Jenny Lee

    2007-08-21T23:59:59.000Z

    Energy in nuclear matter is, in practice, completely characterized at different densities and asymmetries, when the density dependencies of symmetry energy and of energy of symmetric matter are specified. The density dependence of the symmetry energy at subnormal densities produces mass dependence of nuclear symmetry coefficient and, thus, can be constrained by that latter dependence. We deduce values of the mass dependent symmetry coefficients, by using excitation energies to isobaric analog states. The coefficient systematic, for intermediate and high masses, is well described in terms of the symmetry coefficient values of a_a^V=(31.5-33.5) MeV for the volume coefficient and a_a^S=(9-12) MeV for the surface coefficient. These two further correspond to the parameter values describing density dependence of symmetry energy, of L~95 MeV and K_{sym}~25 MeV.

  14. Symmetry Energy as a Function of Density and Mass

    SciTech Connect (OSTI)

    Danielewicz, Pawel; Lee, Jenny [National Superconducting Cyclotron Laboratory and Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824 (United States)

    2007-10-26T23:59:59.000Z

    Energy in nuclear matter is, in practice, completely characterized at different densities and asymmetries, when the density dependencies of symmetry energy and of energy of symmetric matter are specified. The density dependence of the symmetry energy at subnormal densities produces mass dependence of nuclear symmetry coefficient and, thus, can be constrained by that latter dependence. We deduce values of the mass dependent symmetry coefficients, by using excitation energies to isobaric analog states. The coefficient systematic, for intermediate and high masses, is well described in terms of the symmetry coefficient values of a{sub a}{sup V} = (31.5-33.5) MeV for the volume coefficient and a{sub a}{sup S} = (9-12) MeV for the surface coefficient. These two further correspond to the parameter values describing density dependence of symmetry energy, of L{approx}95 MeV and K{sub sym}{approx}25 MeV.

  15. Symmetry Energy as a Function of Density and Mass

    E-Print Network [OSTI]

    Danielewicz, Pawel

    2007-01-01T23:59:59.000Z

    Energy in nuclear matter is, in practice, completely characterized at different densities and asymmetries, when the density dependencies of symmetry energy and of energy of symmetric matter are specified. The density dependence of the symmetry energy at subnormal densities produces mass dependence of nuclear symmetry coefficient and, thus, can be constrained by that latter dependence. We deduce values of the mass dependent symmetry coefficients, by using excitation energies to isobaric analog states. The coefficient systematic, for intermediate and high masses, is well described in terms of the symmetry coefficient values of a_a^V=(31.5-33.5) MeV for the volume coefficient and a_a^S=(9-12) MeV for the surface coefficient. These two further correspond to the parameter values describing density dependence of symmetry energy, of L~95 MeV and K_{sym}~25 MeV.

  16. Collective dynamics of active filament complexes

    E-Print Network [OSTI]

    Nogucci, Hironobu

    2015-01-01T23:59:59.000Z

    Networks of biofilaments are essential for the formation of cellular structures and they support various biological functions. Previous studies have largely investigated the collective dynamics of rod-like biofilaments; however, the shapes of actual subcelluar componensts are often more elaborate. In this study, we investigated an active object composed of two active filaments, which represents a progression from rod-like biofilaments to complex-shaped biofilaments. Specifically, we numerically assessed the collective behaviors of these active objects and observed several types of dynamics depending on the density and the angle of the two filaments as shape parameters of the object. Among the observed collective dynamics, moving density bands that we named 'moving smectic' are reported here for the first time. By using statistical analyses of the orbits of individual objects and the interactions among them, the mechanisms underlying the rise of these dynamics patterns in the system were determined. This study...

  17. Running heading: Bulk density of a clayey subsoil Increase in the bulk density of a Grey Clay subsoil by

    E-Print Network [OSTI]

    Boyer, Edmond

    1 Running heading: Bulk density of a clayey subsoil Increase in the bulk density of a Grey Clay of the prisms were coated by material similar in composition to the topsoil and separated from as the profile dries over summer leading to widening of cracks between prismatic peds, (2) infilling of cracks

  18. Linking climate change to population cycles of hares and C H U A N Y A N * , N I L S C H R . S T E N S E T H , C H A R L E S J . K R E B S and ZHIBIN ZHANG*

    E-Print Network [OSTI]

    Krebs, Charles J.

    Linking climate change to population cycles of hares and lynx C H U A N Y A N * , N I L S C H R to study the effects of density dependence, predation, and climate (both global climate indices of North, University of British Columbia, Vancouver, B.C., Canada V6T 1Z4 Abstract The classic 10-year population cycle

  19. Examining the specific entropy (density of adiabatic invariants) of the outer electron radiation belt

    SciTech Connect (OSTI)

    Borovsky, Joseph E [Los Alamos National Laboratory; Denton, Michael H [LANCASTER UNIV

    2008-01-01T23:59:59.000Z

    Using temperature and number-density measurements of the energetic-electron population from multiple spacecraft in geosynchronous orbit, the specific entropy S = T/n{sup 2/3} of the outer electron radiation belt is calculated. Then 955,527 half-hour-long data intervals are statistically analyzed. Local-time and solar-cycle variations in S are examined. The median value of the specific entropy (2.8 x 10{sup 7} eVcm{sup 2}) is much larger than the specific entropy of other particle populations in and around the magnetosphere. The evolution of the specific entropy through high-speed-stream-driven geomagnetic storms and through magnetic-cloud-driven geomagnetic storms is studied using superposed-epoch analysis. For high-speed-stream-driven storms, systematic variations in the entropy associated with electron loss and gain and with radiation-belt heating are observed in the various storm phases. For magnetic-cloud-driven storms, multiple trigger choices for the data superpositions reveal the effects of interplanetary shock arrival, sheath driving, cloud driving, and recovery phase. The specific entropy S = T/n{sup 2/3} is algebraically expressed in terms of the first and second adiabatic invariants of the electrons: this allows a relativistic expression for S in terms of T and n to be derived. For the outer electron radiation belt at geosynchronous orbit, the relativistic corrections to the specific entropy expression are -15%.

  20. Measuring and Modeling Fault Density for Plume-Fault Encounter Probability Estimation

    SciTech Connect (OSTI)

    Jordan, P.D.; Oldenburg, C.M.; Nicot, J.-P.

    2011-05-15T23:59:59.000Z

    Emission of carbon dioxide from fossil-fueled power generation stations contributes to global climate change. Storage of this carbon dioxide within the pores of geologic strata (geologic carbon storage) is one approach to mitigating the climate change that would otherwise occur. The large storage volume needed for this mitigation requires injection into brine-filled pore space in reservoir strata overlain by cap rocks. One of the main concerns of storage in such rocks is leakage via faults. In the early stages of site selection, site-specific fault coverages are often not available. This necessitates a method for using available fault data to develop an estimate of the likelihood of injected carbon dioxide encountering and migrating up a fault, primarily due to buoyancy. Fault population statistics provide one of the main inputs to calculate the encounter probability. Previous fault population statistics work is shown to be applicable to areal fault density statistics. This result is applied to a case study in the southern portion of the San Joaquin Basin with the result that the probability of a carbon dioxide plume from a previously planned injection had a 3% chance of encountering a fully seal offsetting fault.

  1. QUENCHING STAR FORMATION AT INTERMEDIATE REDSHIFTS: DOWNSIZING OF THE MASS FLUX DENSITY IN THE GREEN VALLEY

    SciTech Connect (OSTI)

    Goncalves, Thiago S.; Menendez-Delmestre, Karin [Observatorio do Valongo, Universidade Federal do Rio de Janeiro, Ladeira Pedro Antonio, 43, Saude 20080-090 Rio de Janeiro (Brazil); Martin, D. Christopher; Wyder, Ted K. [California Institute of Technology, MC 278-17, Pasadena, CA 91125 (United States); Koekemoer, Anton, E-mail: tsg@astro.ufrj.br [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States)

    2012-11-01T23:59:59.000Z

    The bimodality in galaxy properties has been observed at low and high redshifts, with a clear distinction between star-forming galaxies in the blue cloud and passively evolving objects in the red sequence; the absence of galaxies with intermediate properties indicates that the quenching of star formation and subsequent transition between populations must happen rapidly. In this paper, we present a study of over 100 transiting galaxies in the so-called green valley at intermediate redshifts (z {approx} 0.8). By using very deep spectroscopy with the DEIMOS instrument at the Keck telescope we are able to infer the star formation histories of these objects and measure the stellar mass flux density transiting from the blue cloud to the red sequence when the universe was half its current age. Our results indicate that the process happened more rapidly and for more massive galaxies in the past, suggesting a top-down scenario in which the massive end of the red sequence is forming first. This represents another aspect of downsizing, with the mass flux density moving toward smaller galaxies in recent times.

  2. CONSERVATION OF THE IRISH POPULATIONS OF THE POLLAN

    E-Print Network [OSTI]

    McCarthy, T.K.

    CONSERVATION OF THE IRISH POPULATIONS OF THE POLLAN COREGONUS AUTUMNALIS Robert Rosell, C. Harrod on the status of the four extant populations and proposed possible conservation measures. This paper updates

  3. Evolutionary dynamics in set structured populations Corina E. Tarnitaa

    E-Print Network [OSTI]

    Nowak, Martin A.

    Evolutionary dynamics in set structured populations Corina E. Tarnitaa , Tibor Antala , Hisashi a powerful method to study dynamical population structure: evolutionary set theory. The individuals of popu- lation structure on evolutionary and ecological dynamics. These approaches include spatial models

  4. Ecosystem-specific selection pressures revealed through comparative population genomics

    E-Print Network [OSTI]

    Coleman, Maureen L.

    Bacterial populations harbor vast genetic diversity that is continually shaped by abiotic and biotic selective pressures, as well as by neutral processes. Individuals coexisting in the same geographically defined population ...

  5. Diversity waves in collapse-driven population dynamics

    E-Print Network [OSTI]

    Maslov, Sergei

    2015-01-01T23:59:59.000Z

    Populations of species in ecosystems are constrained by the availability of resources within their environment. In effect this means that a growth of one population, needs to be balanced by the reduction in size of others. In neutral models of biodiversity all populations are assumed to change incrementally due to stochastic births and deaths of individuals. Here we propose and model another redistribution mechanism driven by abrupt collapses of the entire population of a single species freeing up resources for the remaining ones. This mechanism may be relevant for communities of bacteria, with strain-specific collapses caused e.g. by invading bacteriophages, or for other ecosystems where infectious diseases play an important role. The emergent property of the population dynamics in our system are cyclic "diversity waves" triggered by collapses of globally dominating populations. The population diversity in the environment peaks at the beginning of each wave and exponentially decreases afterwards. Population ...

  6. Constraining the nuclear symmetry-energy at super-density

    E-Print Network [OSTI]

    Yong, Gao-Chan

    2015-01-01T23:59:59.000Z

    The nuclear symmetry-energy has broad implications in both nuclear physics and astrophysics. Due to hard work of many people, the nuclear symmetry-energy around saturation density has been roughly constrained. However, the nuclear symmetry-energy at super-density is still in chaos. By considering both the effects of the nucleon-nucleon short-rang correlations and the isospin-dependent in-medium inelastic baryon-baryon scattering cross sections in the transport model, two unrelated experimental measurements are simultaneously analyzed. A soft symmetry-energy at super-density is first consistently obtained by the double comparison of the symmetry-energy sensitive observables.

  7. Nuclear Energy Density Functionals Constrained by Low-Energy QCD

    E-Print Network [OSTI]

    Dario Vretenar

    2008-02-06T23:59:59.000Z

    A microscopic framework of nuclear energy density functionals is reviewed, which establishes a direct relation between low-energy QCD and nuclear structure, synthesizing effective field theory methods and principles of density functional theory. Guided by two closely related features of QCD in the low-energy limit: a) in-medium changes of vacuum condensates, and b) spontaneous breaking of chiral symmetry; a relativistic energy density functional is developed and applied in studies of ground-state properties of spherical and deformed nuclei.

  8. Symmetry energy at subnuclear densities deduced from nuclear masses

    E-Print Network [OSTI]

    Kazuhiro Oyamatsu; Kei Iida

    2010-04-19T23:59:59.000Z

    We examine how nuclear masses are related to the density dependence of the symmetry energy. Using a macroscopic nuclear model we calculate nuclear masses in a way dependent on the equation of state of asymmetric nuclear matter. We find by comparison with empirical two-proton separation energies that a smaller symmetry energy at subnuclear densities, corresponding to a larger density symmetry coefficient L, is favored. This tendency, which is clearly seen for nuclei that are neutron-rich, nondeformed, and light, can be understood from the property of the surface symmetry energy in a compressible liquid-drop picture.

  9. Energy Density Inhomogeneities with Polynomial $f(R)$ Cosmology

    E-Print Network [OSTI]

    Sharif, M

    2015-01-01T23:59:59.000Z

    In this paper, we study the effects of polynomial $f(R)$ model on the stability of homogeneous energy density in self-gravitating spherical stellar object. For this purpose, we construct couple of evolution equations which relate the Weyl tensor with matter parameters. We explore different factors responsible for density inhomogeneities with non-dissipative dust, isotropic as well as anisotropic fluids and dissipative dust cloud. We find that shear, pressure, dissipative parameters and $f(R)$ terms affect the existence of inhomogeneous energy density.

  10. Emergence of Attention within a Neural Population

    E-Print Network [OSTI]

    We present a dynamic model of attention based on the Continuum Neural Field Theory that explains attention as being an emergent property of a neural population. This model is experimentally proved to be very robust and able to track one static or moving target in the presence of very strong noise or in the presence of a lot of distractors, even more salient than the target. This attentional property is not restricted to the visual case and can be considered as a generic attentional process of any spatio-temporal continuous input.

  11. ORISE Resources: Population Monitoring in Radiation Emergencies

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr May JunDatastreamsmmcrcalgovInstrumentsrucLas Conchas recoveryLaboratory | NationalJohnSecurityControlsOMB PoliciesInternetPopulation

  12. On the properties of massive Population III stars and metal-free stellar populations

    E-Print Network [OSTI]

    Schrer, D

    2001-01-01T23:59:59.000Z

    We present realistic models for massive Population III stars and stellar populations based on non-LTE model atmospheres, recent stellar evolution tracks and up-to-date evolutionary synthesis models, to study their spectral properties, including their dependence on age, star formation history, and IMF. (..) The main results regarding integrated stellar populations are: * For young bursts and the case of a constant SFR, nebular continuous emission - neglected in previous studies - dominates the spectrum redward of Lyman-alpha (...). Therefore predicted emission line equivalent widths are considerably smaller than found in earlier studies, whereas the detection of the continuum is eased. Nebular line and continuous emission strongly affect the broad band photometric properties of Pop III objects. * Due to stellar evolution, the hardness of the ionising spectrum decreases rapidly, leading to the disappearance of the characteristic HeII 1640 recombination lines after ~ 3 Myr in instantaneous bursts. * The relative...

  13. The Planetary Nebula population of the Sagittarius Dwarf Spheroidal Galaxy

    E-Print Network [OSTI]

    Albert Zijlstra; K. Gesicki; J. R. Walsh; D. Pequignot; P. A. M. van Hoof; D. Minniti

    2006-03-16T23:59:59.000Z

    The identification of two new Planetary Nebulae in the Sagittarius Dwarf Spheroidal Galaxy (Sgr) is presented. This brings the total number to four. The first, StWr 2-21, belongs to the main body of Sgr. The second, the halo PN BoBn 1, has a location, distance and velocity in agreement with the leading tidal tail of Sgr. We estimate that 10 per cent of the Galactic halo consists of Sgr debris. The specific frequency of PNe indicates a total luminosity of Sgr, including its tidal tails, of M_V=-14.1. StWr 2-21 shows a high abundance of [O/H]=-0.23, which confirms the high-metallicity population in Sgr uncovered by Bonaficio et al. (2004). The steep metallicity--age gradient in Sgr is due to ISM removal during the Galactic plane passages, ISM reformation due to stellar mass loss, and possibly accretion of metal-enriched gas from our Galaxy. The ISM re-formation rate of Sgr, from stellar mass loss, is 5 X 10^-4 M_sun yr^-1, amounting to ~10^6 M_sun per orbital period. HST images reveal well-developed bipolar morphologies, and provide clear detections of the central stars. All three stars with deep spectra show WR-lines, suggesting that the progenitor mass and metallicity determines whether a PN central star develops a WR spectrum. One Sgr PN belongs to the class of IR-[WC] stars. Expansion velocities are determined for three nebulae. Comparison with hydrodynamical models indicates an initial density profile of rho ~ r^-3. This is evidence for increasing mass-loss rates on the AGB. Peak mass-loss rates are indicated of ~ 10^-4 M_sun yr^-1. The IR-[WC] PN, He 2-436, provides the sole direct detection of dust in a dwarf spheroidal galaxy, to date.

  14. Revisiting the Uniqueness of Simple Demographics in the US Population

    E-Print Network [OSTI]

    Golle, Philippe

    Revisiting the Uniqueness of Simple Demographics in the US Population Philippe Golle Palo Alto% of the US population can be uniquely identified by gen- der, ZIP code and full date of birth. This short paper revisits the uniqueness of simple demographics in the US population based on the most recent

  15. Proximate Population Factors and Deforestation in Tropical Agricultural Frontiers

    E-Print Network [OSTI]

    Lopez-Carr, David

    Proximate Population Factors and Deforestation in Tropical Agricultural Frontiers David L. Carr are significantly associated at the global and regional scales, evidence for population links to deforestation of thought on population­environment theories relevant to deforestation in tropical agricultural frontiers

  16. Genetic Variability and Population Differentiation in Captive Baird's Tapirs

    E-Print Network [OSTI]

    Ashley, Mary V.

    one of housing and displaying as diverse a collection of species as possible, to one of creating self and Ballou, 1986; Soule et al., 1986]. One obstacle to achieving a self-sustaining captive population- sustaining captive populations that may one day act as a source for restocking wild populations [Ralls

  17. VOL I, ISSUE 1Quarterly Edition Population and Public Policy

    E-Print Network [OSTI]

    Saskatchewan, University of

    VOL I, ISSUE 1Quarterly Edition Population and Public Policy Migration to western Canada increases affect and are affected by public policy decisions. Even the sheer size of the population, the subject of this article, affects public policy because larger populations can usually support a wider range of public

  18. Collisional population transfer in yterbium ions

    SciTech Connect (OSTI)

    Schauer, Martin Michael [Los Alamos National Laboratory; Torgerson, Justin R [Los Alamos National Laboratory; Danielson, Jeremy R [Los Alamos National Laboratory; Zhao, Xinxin [Los Alamos National Laboratory; Nguyen, Ahn - Tuan [UNIV OF PITTSBURGH; Wang, Li - Bang [NATIONAL TSING HUA UNIV

    2009-01-01T23:59:59.000Z

    Long-lived metastable states of Yb+ ions are used for atomic frequency standards, precision measurements, and quantum information research. The effect of population trapping and transfer in these states must be well understood. We report here the transfer of Yb+ ions into the long-lived {sup 2}F{sub 7/2} state by means of collisions between He buffer gas and Yb+ ions held in a linear Paul trap. Transfer rates were measured as functions of buffer-gas pressure and repump-laser power, and the collisional population transfer rates were extracted. The measured transfer rate coefficients are 8.32(75)x10-11 and 8.65(33)x10-11 cm3/s for the collisional processes {sup 2}P{sub 1/2}{yields}{sup 2}D{sub 5/2} and {sup 2}D{sub 3/2}{yields}{sup 2}F{sub 7/2}, respectively.

  19. Uncertainty analysis of densities and isotopics: Handling correlations

    SciTech Connect (OSTI)

    Favorite, J. A.; Armstrong, J. C. [X-Computational Physics Division, Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, NM 87545 (United States); Burr, T. [Computer, Computational, and Statistical Sciences Division, Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, NM 87545 (United States)

    2013-07-01T23:59:59.000Z

    This paper discusses two cases of correlated parameters in uncertainty analyses: (1) the case of measured mass, density, and volume or spatial dimension correlations; and (2) the case of measured material isotopics, where increasing one atom fraction must cause the others to decrease. In the first case, an equation is derived that has a term due to uncertain density, a term due to uncertain dimensions, and a term due to the correlation between density and dimensions. In a numerical test problem, this equation gives the same result as the standard equation that treats mass and dimensions independently. In the case of isotopics, an equation is derived relating the uncertainty due to uncertain isotopic fractions to the sensitivities to isotopic densities, which are easier to calculate. The equation is verified in a test problem. (authors)

  20. Real time density functional simulations of quantum scale conductance

    E-Print Network [OSTI]

    Evans, Jeremy Scott

    2009-01-01T23:59:59.000Z

    We study electronic conductance through single molecules by subjecting a molecular junction to a time dependent potential and propagating the electronic state in real time using time-dependent density functional theory ...

  1. Density of states and order parameter in dirty anisotropic superconductors

    E-Print Network [OSTI]

    Pokrovsky, SV; Pokrovsky, Valery L.

    1996-01-01T23:59:59.000Z

    We analyze in detail how the scattering by nonmagnetic impurities affects the shape and amplitude of the order parameter (OF) and the density of states in anisotropic superconductors in the framework of BCS theory. Special attention is paid...

  2. Direct experimental determination of spectral densities of molecular complexes

    SciTech Connect (OSTI)

    Pachn, Leonardo A. [Grupo de Fsica Atmica y Molecular, Instituto de Fsica, Facultad de Ciencias Exactas y Naturales, Universidad de Antioquia UdeA, Calle 70 No. 52-21, Medelln (Colombia); Chemical Physics Theory Group, Department of Chemistry and Center for Quantum Information and Quantum Control, University of Toronto, Toronto, Ontario M5S 3H6 (Canada); Brumer, Paul [Chemical Physics Theory Group, Department of Chemistry and Center for Quantum Information and Quantum Control, University of Toronto, Toronto, Ontario M5S 3H6 (Canada)

    2014-11-07T23:59:59.000Z

    Determining the spectral density of a molecular system immersed in a proteomic scaffold and in contact to a solvent is a fundamental challenge in the coarse-grained description of, e.g., electron and energy transfer dynamics. Once the spectral density is characterized, all the time scales are captured and no artificial separation between fast and slow processes need to be invoked. Based on the fluorescence Stokes shift function, we utilize a simple and robust strategy to extract the spectral density of a number of molecular complexes from available experimental data. Specifically, we show that experimental data for dye molecules in several solvents, amino acid proteins in water, and some photochemical systems (e.g., rhodopsin and green fluorescence proteins), are well described by a three-parameter family of sub-Ohmic spectral densities that are characterized by a fast initial Gaussian-like decay followed by a slow algebraic-like decay rate at long times.

  3. An evolutionary fuel assembly design for high power density BWRs

    E-Print Network [OSTI]

    Karahan, Aydin

    2007-01-01T23:59:59.000Z

    An evolutionary BWR fuel assembly design was studied as a means to increase the power density of current and future BWR cores. The new assembly concept is based on replacing four traditional assemblies and large water gap ...

  4. atheroprotective high-density lipoprotein: Topics by E-print...

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

    the mean-field energy functional. By studying the latter we derive global properties of high-density ground state configurations in bounded domains and in infinite space. Our main...

  5. Why are Fluid Densities So Low in Carbon Nanotubes?

    E-Print Network [OSTI]

    Gerald J. Wang; Nicolas G. Hadjiconstantinou

    2014-09-27T23:59:59.000Z

    The equilibrium density of fluids under nanoconfinement can differ substantially from their bulk density. Using a mean-field approach to describe the energetic landscape near the carbon nanotube (CNT) wall, we obtain analytical results describing the lengthscales associated with the layering observed at the fluid-CNT interface. When combined with molecular simulation results for the fluid density in the layered region, this approach allows us to derive a closed-form prediction for the overall equilibrium fluid density as a function of the CNT radius that is in excellent agreement with molecular dynamics simulations. We also show how aspects of this theory can be extended to describe water confined within CNTs and find good agreement with results from the literature.

  6. Effect of Lithium PFC Coatings on NSTX Density Control

    SciTech Connect (OSTI)

    Kugel, H W; Bell, M G; Bush, C; Gates, D; Gray, T; Kaita, R; Leblanc, B; Maingi, R; Majeski, R; Mansfield, D; Mueller, D; Raman, R; Roquemore, A L; Sabbagh, S; Skinner, C H; Soukhanovskii, V; Stevenson, T; Zakharov, L

    2006-08-21T23:59:59.000Z

    Lithium coatings on the graphite plasma facing components (PFCs) in NSTX are being investigated as a tool for density profile control and reducing the recycling of hydrogen isotopes. Repeated lithium pellet injection into Center Stack Limited and Lower Single Null Ohmic Helium Discharges were used to coat graphite surfaces that had been pre-conditioned with Ohmic Helium Discharges of the same shape to reduce their contribution to hydrogen isotope recycling. The following deuterium NBI reference discharges exhibited a reduction in density by a factor of about 3 for limited and 2 for diverted plasmas respectively, and peaked density profiles. Recently, a lithium evaporator has been used to apply thin coatings on conditioned and unconditioned PFCs. Effects on the plasma density and the impurities were obtained by pre-conditioning the PFCs with ohmic helium discharges, and performing the first deuterium NBI discharge as soon as possible after applying the lithium coating.

  7. Optimal-transport formulation of electronic density-functional theory

    E-Print Network [OSTI]

    Giuseppe Buttazzo; Luigi De Pascale; Paola Gori-Giorgi

    2012-05-21T23:59:59.000Z

    The most challenging scenario for Kohn-Sham density functional theory, that is when the electrons move relatively slowly trying to avoid each other as much as possible because of their repulsion (strong-interaction limit), is reformulated here as an optimal transport (or mass transportation theory) problem, a well established field of mathematics and economics. In practice, we show that solving the problem of finding the minimum possible internal repulsion energy for $N$ electrons in a given density $\\rho(\\rv)$ is equivalent to find the optimal way of transporting $N-1$ times the density $\\rho$ into itself, with cost function given by the Coulomb repulsion. We use this link to put the strong-interaction limit of density functional theory on firm grounds and to discuss the potential practical aspects of this reformulation.

  8. The design of high power density annular fuel for LWRs

    E-Print Network [OSTI]

    Yuan, Yi, 1975-

    2004-01-01T23:59:59.000Z

    Fuel performance models have been developed to assess the performance of internally and externally cooled LWR annular fuel. Such fuel may be operated at 30-50% higher core power density than the current operating LWRs, and ...

  9. Computing the Density of States of Boolean Formulas

    E-Print Network [OSTI]

    Keinan, Alon

    Computing the Density of States of Boolean Formulas Stefano Ermon, Carla P. Gomes, and Bart Selman of configurations that violate exactly E clauses, for all values of E. We propose a novel Markov Chain Monte Carlo

  10. Does Cosmological Vacuum Energy Density have an Electric Reason ?

    E-Print Network [OSTI]

    Claus W. Turtur

    2004-03-11T23:59:59.000Z

    Rather uncomplicated calculations by hand display a surprising connection between the energy density of the vacuum and the diameter and age of the universe. Among other things, the result explains the observation of the accelerated expansion of the universe.

  11. Low density lipoprotein fraction assay for cardiac disease risk

    DOE Patents [OSTI]

    Krauss, R.M.; Blanche, P.J.; Orr, J.

    1999-07-20T23:59:59.000Z

    A variable rate density gradient electrophoric gel is described which separates LDL subfractions with the precision of ultracentrifugation techniques. Also, an innovative bottom inlet mixing chamber particularly useful for producing these gels is described. 8 figs.

  12. Direct Experimental Determination of Spectral Densities of Molecular Complexes

    E-Print Network [OSTI]

    Leonardo A. Pachon; Paul Brumer

    2014-10-15T23:59:59.000Z

    Determining the spectral density of a molecular system immersed in a proteomic scaffold and in contact to a solvent is a fundamental challenge in the coarse-grained description of, e.g., electron and energy transfer dynamics. Once the spectral density is characterized, all the time scales are captured and no artificial separation between fast and slow processes need be invoked. Based on the fluorescence Stokes shift function, we utilize a simple and robust strategy to extract the spectral density of a number of molecular complexes from available experimental data. Specifically, we show that experimental data for dye molecules in several solvents, amino acid proteins in water, and some photochemical systems (e.g., rhodopsin and green fluorescence proteins), are well described by a three-parameter family of sub-Ohmic spectral densities that are characterized by a fast initial Gaussian-like decay followed by a slow algebraic-like decay rate at long times.

  13. Measurements of neutral helium density in helicon plasmas

    SciTech Connect (OSTI)

    Houshmandyar, Saeid; Sears, Stephanie H.; Thakur, Saikat Chakraborty; Carr, Jerry Jr.; Galante, Matthew E.; Scime, Earl E. [Department of Physics, West Virginia University, Morgantown, West Virginia 26506-6315 (United States)

    2010-10-15T23:59:59.000Z

    Laser-induced-fluorescence (LIF) is used to measure the density of helium atoms in a helicon plasma source. For a pump wavelength of 587.725 nm (vacuum) and laser injection along the magnetic field, the LIF signal exhibits a signal decrease at the Doppler shifted central wavelength. The drop in signal results from the finite optical depth of the plasma and the magnitude of the decrease is proportional to the density of excited state neutral atoms. Using Langmuir probe measurements of plasma density and electron temperature and a collisional-radiative model, the absolute ground state neutral density is calculated from the optical depth measurements. Optimal plasma performance, i.e., the largest neutral depletion on the axis of the system, is observed for antenna frequencies of 13.0 and 13.5 MHz and magnetic field strengths of 550-600 G.

  14. A density functional study of actinyl containing complexes.

    E-Print Network [OSTI]

    Berard, Joel J.

    2008-01-01T23:59:59.000Z

    ??Density functional (DFT) methods are first used to study 22 of the most stable solution-phase UN4O12 isomers containing uranyl nitrate, UO2(NO3)2. Based on relative free (more)

  15. Estimating Geometric Dislocation Densities in Polycrystalline Materialsfrom Orientation Imaging Microscopy

    SciTech Connect (OSTI)

    Man, Chi-Sing [University of Kentucky; Gao, Xiang [University of Kentucky; Godefroy, Scott [University of Kentucky; Kenik, Edward A [ORNL

    2010-01-01T23:59:59.000Z

    Herein we consider polycrystalline materials which can be taken as statistically homogeneous and whose grains can be adequately modeled as rigid-plastic. Our objective is to obtain, from orientation imaging microscopy (OIM), estimates of geometrically necessary dislocation (GND) densities.

  16. Diffusion driven object propulsion in density stratified fluids

    E-Print Network [OSTI]

    Lenahan, Conor (Conor P.)

    2009-01-01T23:59:59.000Z

    An experimental study was conducted in order to verify the appropriateness of a two dimensional model of the flow creating diffusion driven object propulsion in density stratified fluids. Initial flow field experiments ...

  17. A novel density of state method for complex action systems

    E-Print Network [OSTI]

    Biagio Lucini; Kurt Langfeld

    2014-11-01T23:59:59.000Z

    Recently, a new and efficient algorithm (the LLR method) has been proposed for computing densities of states in statistical systems and gauge theories. In this talk, we explore whether this novel density of states method can be applied to numerical computations of observables in systems for which the action is complex. To this purpose, we introduce a generalised density of states, in terms of which integrals of oscillating observables can be determined semi-analytically, and we define a strategy to compute it with the LLR method. As a case study, we apply these ideas to the Z(3) spin model at finite density, finding a remarkable agreement of our results for the phase twist with those obtained with the worm algorithm for all explored chemical potentials, including values for which there are cancellations over sixteen orders of magnitude. These findings open new perspectives for dealing with the sign problem on physically more relevant systems.

  18. Paper area density measurement from forward transmitted scattered light

    DOE Patents [OSTI]

    Koo, Jackson C. (San Ramon, CA)

    2001-01-01T23:59:59.000Z

    A method whereby the average paper fiber area density (weight per unit area) can be directly calculated from the intensity of transmitted, scattered light at two different wavelengths, one being a non-absorpted wavelength. Also, the method makes it possible to derive the water percentage per fiber area density from a two-wavelength measurement. In the optical measuring technique optical transmitted intensity, for example, at 2.1 microns cellulose absorption line is measured and compared with another scattered, optical transmitted intensity reference in the nearby spectrum region, such as 1.68 microns, where there is no absorption. From the ratio of these two intensities, one can calculate the scattering absorption coefficient at 2.1 microns. This absorption coefficient at this wavelength is, then, experimentally correlated to the paper fiber area density. The water percentage per fiber area density can be derived from this two-wavelength measurement approach.

  19. Low density lipoprotein fraction assay for cardiac disease risk

    DOE Patents [OSTI]

    Krauss, Ronald M. (Berkeley, CA); Blanche, Patricia J. (Berkeley, CA); Orr, Joseph (San Pablo, CA)

    1999-01-01T23:59:59.000Z

    A variable rate density gradient electrophoric gel is described which separate LDL subfractions with the precision of ultracentrifugation techniques. Also, an innovative bottom inlet mixing chamber particularly useful for producing these gels is described.

  20. Breeding bird populations and habitat associations within the Savannah River Site (SRS).

    SciTech Connect (OSTI)

    Gauthreaux, Sidney, A.; Steven J. Wagner.

    2005-06-29T23:59:59.000Z

    Gauthreaux, Sidney, A., and Steven J. Wagner. 2005. Breeding bird populations and habitat associations within the Savannah River Site (SRS). Final Report. USDA Forest Service, Savannah River, Aiken, SC. 48 pp. Abstract: During the 1970's and 1980's a dramatic decline occurred in the populations of Neotropical migratory birds, species that breed in North America and winter south of the border in Central and South America and in the Caribbean. In 1991 an international initiative was mounted by U. S. governmental land management agencies, nongovernmental conservation agencies, and the academic and lay ornithological communities to understand the decline of Neotropical migratory birds in the Americas. In cooperation with the USDA Forest Service - Savannah River (FS - SR) we began 1992 a project directed to monitoring population densities of breeding birds using the Breeding Bird Census (BBC) methodology in selected habitats within the Savannah River Site SRS. In addition we related point count data on the occurrence of breeding Neotropical migrants and other bird species to the habitat data gathered by the Forest Inventory and Analysis (FIA) program of the USDA Forest Service and data on habitat treatments within forest stands.

  1. The Dark Bursts population in a complete sample of bright Swift Long Gamma-Ray Bursts

    E-Print Network [OSTI]

    A. Melandri; B. Sbarufatti; P. D'Avanzo; R. Salvaterra; S. Campana; S. Covino; S. D. Vergani; L. Nava; G. Ghisellini; G. Ghirlanda; D. Fugazza; V. Mangano; M. Capalbi; G. Tagliaferri

    2012-02-14T23:59:59.000Z

    We study the properties of the population of optically dark events present in a carefully selected complete sample of bright Swift long gamma-ray bursts. The high level of completeness in redshift of our sample (52 objects out of 58) allow us to establish the existence of a genuine dark population and we are able to estimate the maximum fraction of dark burst events (~30%) expected for the whole class of long gamma-ray burst. The redshift distribution of this population of dark bursts is similar to the one of the whole sample. Interestingly, the rest-frame X-ray luminosity (and the de-absorbed X-ray flux) of the sub-class of dark bursts is slightly higher than the average luminosity of the non-dark events. At the same time the prompt properties do not differ and the optical flux of dark events is at the lower tail of the optical flux distribution, corrected for Galactic absorption. All these properties suggest that dark bursts events generate in much denser environments with respect to normal bright events. We can therefore exclude the high-z and the low-density scenarios and conclude that the major cause of the origin of optically dark events is the dust extinction.

  2. Experiments to populate and validate a processing model for polyurethane foam :

    SciTech Connect (OSTI)

    Mondy, Lisa Ann; Rao, Rekha Ranjana; Shelden, Bion; Soehnel, Melissa Marie; O'Hern, Timothy J.; Grillet, Anne; Celina, Mathias Christopher; Wyatt, Nicholas B.; Russick, Edward Mark; Bauer, Stephen J.; Hileman, Michael Bryan; Urquhart, Alexander; Thompson, Kyle Richard; Smith, David Michael

    2014-03-01T23:59:59.000Z

    We are developing computational models to elucidate the expansion and dynamic filling process of a polyurethane foam, PMDI. The polyurethane of interest is chemically blown, where carbon dioxide is produced via the reaction of water, the blowing agent, and isocyanate. The isocyanate also reacts with polyol in a competing reaction, which produces the polymer. Here we detail the experiments needed to populate a processing model and provide parameters for the model based on these experiments. The model entails solving the conservation equations, including the equations of motion, an energy balance, and two rate equations for the polymerization and foaming reactions, following a simplified mathematical formalism that decouples these two reactions. Parameters for the polymerization kinetics model are reported based on infrared spectrophotometry. Parameters describing the gas generating reaction are reported based on measurements of volume, temperature and pressure evolution with time. A foam rheology model is proposed and parameters determined through steady-shear and oscillatory tests. Heat of reaction and heat capacity are determined through differential scanning calorimetry. Thermal conductivity of the foam as a function of density is measured using a transient method based on the theory of the transient plane source technique. Finally, density variations of the resulting solid foam in several simple geometries are directly measured by sectioning and sampling mass, as well as through x-ray computed tomography. These density measurements will be useful for model validation once the complete model is implemented in an engineering code.

  3. From massive gravity to dark matter density II

    E-Print Network [OSTI]

    G. Scharf

    2009-02-18T23:59:59.000Z

    As previously observed the massless limit of massive gravity leads to a modification of general relativity. Here we study spherically symmetric solutions of the modified field equations which contain normal matter together with a dark energy density. If the dark density profile is assumed to be known, the whole problem is reduced to a linear first order differential equation which can be solved by quadratures.

  4. Density dependence of symmetry free energy of hot nuclei

    E-Print Network [OSTI]

    S. K. Samaddar; J. N. De; X. Vinas; M. Centelles

    2008-09-04T23:59:59.000Z

    The density and excitation energy dependence of symmetry energy and symmetry free energy for finite nuclei are calculated microscopically in a microcanonical framework taking into account thermal and expansion effects. A finite-range momentum and density dependent two-body effective interaction is employed for this purpose. The role of mass, isospin and equation of state (EoS) on these quantities is also investigated; our calculated results are in consonance with the available experimental data.

  5. The benchmark of gutzwiller density functional theory in hydrogen systems

    SciTech Connect (OSTI)

    Yao, Y.; Wang, Cai-Zhuang; Ho, Kai-Ming

    2012-02-23T23:59:59.000Z

    We propose an approximate form of the exchange-correlation energy functional for the Gutzwiller density functional theory. It satisfies certain physical constraints in both weak and strong electron correlation limits. We benchmark the Gutzwiller density functional approximation in the hydrogen systems, where the static correlation error is shown to be negligible. The good transferability is demonstrated by applications to the hydrogen molecule and some crystal structures.

  6. Preface: Special Topic on Advances in Density Functional Theory

    SciTech Connect (OSTI)

    Yang, Weitao [Department of Chemistry and Department of Physics, Duke University, Durham, North Carolina 27708 (United States)] [Department of Chemistry and Department of Physics, Duke University, Durham, North Carolina 27708 (United States)

    2014-05-14T23:59:59.000Z

    This Special Topic Issue on the Advances in Density Functional Theory, published as a celebration of the fifty years of density functional theory, contains a retrospective article, a perspective article, and a collection of original research articles that showcase recent theoretical advances in the field. It provides a timely discussion reflecting a cross section of our understanding, and the theoretical and computational developments, which have significant implications in broad areas of sciences and engineering.

  7. Density Functional Theory with Dissipation: Transport through Single Molecules

    SciTech Connect (OSTI)

    Kieron Burke

    2012-04-30T23:59:59.000Z

    A huge amount of fundamental research was performed on this grant. Most of it focussed on fundamental issues of electronic structure calculations of transport through single molecules, using density functional theory. Achievements were: (1) First density functional theory with dissipation; (2) Pseudopotential plane wave calculations with master equation; (3) Weak bias limit; (4) Long-chain conductance; and (5) Self-interaction effects in tunneling.

  8. Molecular Binding Energies from Partition Density Functional Theory

    SciTech Connect (OSTI)

    Nafziger, J.; Wu, Q.; Wasserman, A.

    2011-12-21T23:59:59.000Z

    Approximate molecular calculations via standard Kohn-Sham density functional theory are exactly reproduced by performing self-consistent calculations on isolated fragments via partition density functional theory [P. Elliott, K. Burke, M. H. Cohen, and A. Wasserman, Phys. Rev. A 82, 024501 (2010)]. We illustrate this with the binding curves of small diatomic molecules. We find that partition energies are in all cases qualitatively similar and numerically close to actual binding energies. We discuss qualitative features of the associated partition potentials.

  9. Taming Density Functional Theory by Coarse-Graining

    E-Print Network [OSTI]

    Paul E. Lammert

    2010-08-10T23:59:59.000Z

    The standard (``fine-grained'') interpretation of quantum density functional theory, in which densities are specified with infinitely-fine spatial resolution, is mathematically unruly. Here, a coarse-grained version of DFT, featuring limited spatial resolution, and its relation to the fine-grained theory in the $L^1\\cap L^3$ formulation of Lieb, is studied, with the object of showing it to be not only mathematically well-behaved, but consonant with the spirit of DFT, practically (computationally) adequate and sufficiently close to the standard interpretation as to accurately reflect its non-pathological properties. The coarse-grained interpretation is shown to be a good model of formal DFT in the sense that: all densities are (ensemble)-V-representable; the intrinsic energy functional $F$ is a continuous function of the density and the representing external potential is the (directional) functional derivative of the intrinsic energy. Also, the representing potential $v[\\rho]$ is quasi-continuous, in that $v[\\rho]\\rho$ is continuous as a function of $\\rho$. The limit of coarse-graining scale going to zero is studied to see if convergence to the non-pathological aspects of the fine-grained theory is adequate to justify regarding coarse-graining as a good approximation. Suitable limiting behaviors or intrinsic energy, densities and representing potentials are found. Intrinsic energy converges monotonically, coarse-grained densities converge uniformly strongly to their low-intrinsic-energy fine-grainings, and $L^{3/2}+L^\\infty$ representability of a density is equivalent to the existence of a convergent sequence of coarse-grained potential/ground-state density pairs.

  10. Non-invasive fluid density and viscosity measurement

    DOE Patents [OSTI]

    Sinha, Dipen N. (Los Alamos, NM)

    2012-05-01T23:59:59.000Z

    The noninvasively measurement of the density and viscosity of static or flowing fluids in a section of pipe such that the pipe performs as the sensing apparatus, is described. Measurement of a suitable structural vibration resonance frequency of the pipe and the width of this resonance permits the density and viscosity to be determined, respectively. The viscosity may also be measured by monitoring the decay in time of a vibration resonance in the pipe.

  11. Density Evolution in the New Modified Chaplygin Gas Model

    E-Print Network [OSTI]

    Surajit Chattopadhyay; Ujjal Debnath

    2008-05-01T23:59:59.000Z

    In this paper, we have considered new modified Chaplygin gas (NMCG) model which interpolates between radiation at early stage and $\\Lambda$CDM at late stage. This model is regarded as a unification of dark energy and dark matter (with general form of matter). We have derived the density parameters from the equation of motion for the interaction between dark energy and dark matter. Also we have studied the evolution of the various components of density parameters.

  12. The Performance of Density Functionals for Sulfate-Water Clusters

    SciTech Connect (OSTI)

    Mardirossian, Narbe; Lambrecht, Daniel S.; McCaslin, Laura; Xantheas, Sotiris S.; Head-Gordon, Martin P.

    2013-03-12T23:59:59.000Z

    The performance of 24 density functionals, Hartree-Fock, and MP2 is assessed with respect to the energetics of 49 sulfate-water clusters with between three and six water molecules. Included among the density functionals are GGA, meta-GGA, hybrid GGA, hybrid meta-GGA, and double hybrid density functionals, as well as the LDA. Three types of dispersion corrections (VV10, XDM, and -D) are tested in conjunction with these functionals. The functionals are compared using the relative and binding energies of the sulfatewater clusters as the main criteria. It is discovered that a majority of current density functionals are unable to simultaneously capture the physics necessary to describe both the relative and binding energies of the anionic solvation clusters. The only density functionals that perform acceptably with respect to both measures are XYG3 and XYGJOS, primarily due to their balanced treatment of exchange and correlation. On the other hand, density functionals with exact exchange that lack nonlocal correlation tend to perform well only for the relative energies. However, there is evidence that hybrid density functionals that provide a more comprehensive treatment of local correlation through their dependence on the kinetic energy density and their ability to treat the inhomogeneities in the present system can partially resolve this issue. While dispersion correction functionals cannot replace the accuracy provided by MP2 correlation, it is shown that the proper combination of a hybrid GGA functional with a dispersion correction functional can lead to drastic improvements in the binding energies of the parent functional, while preserving its performance with respect to the relative energies.

  13. High speed measurements of neutral beam turn-on and impact of beam modulation on measurements of ion density

    SciTech Connect (OSTI)

    Grierson, B. A., E-mail: bgriers@pppl.gov; Grisham, L. [Princeton Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08543 (United States); Burrell, K. H.; Crowley, B.; Scoville, J. T. [General Atomics, P.O. Box 85608, San Diego, California 92186-5608 (United States)

    2014-10-15T23:59:59.000Z

    Modulation of neutral beams on tokamaks is performed routinely, enabling background rejection for active spectroscopic diagnostics, and control of injected power and torque. We find that there exists an anomalous initial transient in the beam neutrals delivered to the tokamak that is not accounted for by the accelerator voltage and power supply current. Measurements of the charge-exchange and beam photoemission on the DIII-D tokamak [J. L. Luxon, Nucl. Fusion 42, 614 (2002)] at high speed (200 ?s) reveal that the energy of the beam neutrals is constant, but the density of beam neutrals displays dramatic variation in the first 23 ms following beam turn-on. The impact of this beam density variation on inferred ion densities and impurity transport is presented, with suggested means to correct for the anomalous transient.

  14. High energy-density water: density functional theory calculations of structure and electrical conductivity.

    SciTech Connect (OSTI)

    Desjarlais, Michael Paul; Mattsson, Thomas Kjell Rene

    2006-03-01T23:59:59.000Z

    Knowledge of the properties of water is essential for correctly describing the physics of shock waves in water as well as the behavior of giant planets. By using finite temperature density functional theory (DFT), we have investigated the structure and electronic conductivity of water across three phase transitions (molecular liquid/ ionic liquid/super-ionic/electronic liquid). There is a rapid transition to ionic conduction at 2000 K and 2 g/cm{sup 3} while electronic conduction dominates at temperatures above 6000 K. We predict that the fluid bordering the super-ionic phase is conducting above 4000 K and 100 GPa. Earlier work instead has the super-ionic phase bordering an insulating fluid, with a transition to metallic fluid not until 7000 K and 250 GPa. The tools and expertise developed during the project can be applied to other molecular systems, for example, methane, ammonia, and CH foam. We are now well positioned to treat also complex molecular systems in the HEDP regime of phase-space.

  15. Nuclear Density Functional Theory and the Equation of State

    E-Print Network [OSTI]

    Yeunhwan Lim

    2011-04-06T23:59:59.000Z

    A nuclear density functional can be used to find the binding energy and shell structure of nuclei and the energy gap in superconducting nuclear matter. In this paper, we study the possible application of a nuclear density functional theory to nuclear astrophysics. From energy density functional theory, we can deduce the interaction between nucleons to find a rough estimate of the charge radius of the specific nuclei. Compared to the Finite-Range Thomas Fermi model, we include three-body forces, which might be important at densities several times that of nuclear matter density. We also add the momentum dependent interaction to take into account the effective mass of the nucleons. We study matter in the neutron star crust using the Wigner-Seitz cell method. By constructing the mass-radius relation of neutron stars and investigating lepton-rich nuclear matter in proto-neutron stars, we find that the density functional can be used to construct an equation of state of hot dense matter.

  16. Observation of low magnetic field density peaks in helicon plasma

    SciTech Connect (OSTI)

    Barada, Kshitish K.; Chattopadhyay, P. K.; Ghosh, J.; Kumar, Sunil; Saxena, Y. C. [Institute for Plasma Research, Bhat, Gandhinagar 382428 (India)

    2013-04-15T23:59:59.000Z

    Single density peak has been commonly observed in low magnetic field (<100 G) helicon discharges. In this paper, we report the observations of multiple density peaks in low magnetic field (<100 G) helicon discharges produced in the linear helicon plasma device [Barada et al., Rev. Sci. Instrum. 83, 063501 (2012)]. Experiments are carried out using argon gas with m = +1 right helical antenna operating at 13.56 MHz by varying the magnetic field from 0 G to 100 G. The plasma density varies with varying the magnetic field at constant input power and gas pressure and reaches to its peak value at a magnetic field value of {approx}25 G. Another peak of smaller magnitude in density has been observed near 50 G. Measurement of amplitude and phase of the axial component of the wave using magnetic probes for two magnetic field values corresponding to the observed density peaks indicated the existence of radial modes. Measured parallel wave number together with the estimated perpendicular wave number suggests oblique mode propagation of helicon waves along the resonance cone boundary for these magnetic field values. Further, the observations of larger floating potential fluctuations measured with Langmuir probes at those magnetic field values indicate that near resonance cone boundary; these electrostatic fluctuations take energy from helicon wave and dump power to the plasma causing density peaks.

  17. Testing gravity with halo density profiles observed through gravitational lensing

    SciTech Connect (OSTI)

    Narikawa, Tatsuya; Yamamoto, Kazuhiro, E-mail: narikawa@theo.phys.sci.hiroshima-u.ac.jp, E-mail: kazuhiro@hiroshima-u.ac.jp [Department of Physical Science, Hiroshima University, Higashi-Hiroshima 739-8526 (Japan)

    2012-05-01T23:59:59.000Z

    We present a new test of the modified gravity endowed with the Vainshtein mechanism with the density profile of a galaxy cluster halo observed through gravitational lensing. A scalar degree of freedom in the galileon modified gravity is screened by the Vainshtein mechanism to recover Newtonian gravity in high-density regions, however it might not be completely hidden on the outer side of a cluster of galaxies. Then the modified gravity might yield an observational signature in a surface mass density of a cluster of galaxies measured through gravitational lensing, since the scalar field could contribute to the lensing potential. We investigate how the transition in the Vainshtein mechanism affects the surface mass density observed through gravitational lensing, assuming that the density profile of a cluster of galaxies follows the original Navarro-Frenk-White (NFW) profile, the generalized NFW profile and the Einasto profile. We compare the theoretical predictions with observational results of the surface mass density reported recently by other researchers. We obtain constraints on the amplitude and the typical scale of the transition in the Vainshtein mechanism in a subclass of the generalized galileon model.

  18. The Birth of a Galaxy: Primoridal Metal Enrichment and Population II Stellar Populations

    E-Print Network [OSTI]

    Wise, John H; Norman, Michael L; Abel, Tom

    2010-01-01T23:59:59.000Z

    Population III stars first form in dark matter halos with masses around 10^6 Msun. By definition, they are metal-free, and their protostellar collapse is driven by molecular hydrogen cooling in the gas-phase, leading to a massive characteristic mass ~100 Msun and suppressed fragmentation. Population II stars with lower characteristic masses form when the star-forming gas reaches a critical metallicity of 10^{-6} - 10^{-3.5} Zsun, depending on whether dust cooling is important. We present adaptive mesh refinement radiation hydrodynamics simulations that follows the transition from Population III to II star formation. We model stellar radiative feedback with adaptive ray tracing. A top-heavy initial mass function for the Population III stars is considered, resulting in a plausible distribution of pair-instability supernovae and associated metal enrichment. We find that the gas fraction recovers from 5 percent to nearly the cosmic fraction in halos with merger histories rich in halos above 10^7 Msun. A single pa...

  19. Population and Climate Change:Population and Climate Change: Are they related?Are they related?

    E-Print Network [OSTI]

    Kalnay, Eugenia

    depletion: water, oil, fisheries, topsoil, etc. Resource wars and civil conflicts Malnutrition and world! We are still missing the most important component of the Earth System: the Human System #12;Is, population would be much smaller! Growth in grain production is now flattening out Industrial farming

  20. Engineering the initial state in broadband population inversion

    E-Print Network [OSTI]

    Bo Y. Chang; Sheokmin Shin; Ignacio R. Sola

    2015-03-03T23:59:59.000Z

    Quantum systems with sublevel structures prevent full population inversion from one manifold of sublevels to the other using strong ultrafast resonant pulses. In this work we explain the mechanism by which this population transfer is blocked. We then develop a novel concept of geometric control, assuming full or partial coherent manipulation within the manifolds and show that by preparing specific coherent superpositions in the initial manifold, full population inversion or full population blockade, {\\it i.e} laser-induced transparency, can be achieved. In particular, by parallel population transfer we show how population inversion between the manifolds can be obtained with minimal pulse area. As the number of sublevels increases, population inversion can overcome the pulse area theorem at the expense of full control over the initial manifold of sublevels.