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1

Transport Energy Use and Population Density  

NLE Websites -- All DOE Office Websites (Extended Search)

Transport Energy Use and Population Density Transport Energy Use and Population Density Speaker(s): Masayoshi Tanishita Date: July 1, 2004 - 10:00pm Location: Bldg. 90 Seminar Host/Point of Contact: Jonathan Sinton After Peter Newman and Jeffrey Kenworthy published "Cities and Automobile Dependence" in 1989, population density was brought to public attention as an important factor to explain transport mobility and energy use. However, several related issues still remain open: Is an increase in population density more effective than rising gas prices in reducing transport energy use? How much does per capita transport energy use change as population density in cities changes? And what kind of factors influence changes in population density? In this presentation, using city-level data in the US, Japan and other countries, the population-density elasticity of

2

Vehicle Technologies Office: Fact #661: February 7, 2011 Population Density  

NLE Websites -- All DOE Office Websites (Extended Search)

1: February 7, 1: February 7, 2011 Population Density to someone by E-mail Share Vehicle Technologies Office: Fact #661: February 7, 2011 Population Density on Facebook Tweet about Vehicle Technologies Office: Fact #661: February 7, 2011 Population Density on Twitter Bookmark Vehicle Technologies Office: Fact #661: February 7, 2011 Population Density on Google Bookmark Vehicle Technologies Office: Fact #661: February 7, 2011 Population Density on Delicious Rank Vehicle Technologies Office: Fact #661: February 7, 2011 Population Density on Digg Find More places to share Vehicle Technologies Office: Fact #661: February 7, 2011 Population Density on AddThis.com... Fact #661: February 7, 2011 Population Density The density of the population in the U.S., measured as the number of people

3

Uncertainty Quantification Techniques for Population Density Estimates Derived from Sparse Open Source Data  

SciTech Connect

The Population Density Tables (PDT) project at the Oak Ridge National Laboratory (www.ornl.gov) is developing population density estimates for specific human activities under normal patterns of life based largely on information available in open source. Currently, activity based density estimates are based on simple summary data statistics such as range and mean. Researchers are interested in improving activity estimation and uncertainty quantification by adopting a Bayesian framework that considers both data and sociocultural knowledge. Under a Bayesian approach knowledge about population density may be encoded through the process of expert elicitation. Due to the scale of the PDT effort which considers over 250 countries, spans 40 human activity categories, and includes numerous contributors, an elicitation tool is required that can be operationalized within an enterprise data collection and reporting system. Such a method would ideally require that the contributor have minimal statistical knowledge, require minimal input by a statistician or facilitator, consider human difficulties in expressing qualitative knowledge in a quantitative setting, and provide methods by which the contributor can appraise whether their understanding and associated uncertainty was well captured. This paper introduces an algorithm that transforms answers to simple, non-statistical questions into a bivariate Gaussian distribution as the prior for the Beta distribution. Based on geometric properties of the Beta distribution parameter feasibility space and the bivariate Gaussian distribution, an automated method for encoding is developed that responds to these challenging enterprise requirements. Though created within the context of population density, this approach may be applicable to a wide array of problem domains requiring informative priors for the Beta distribution.

Stewart, Robert N [ORNL; White, Devin A [ORNL; Urban, Marie L [ORNL; Morton, April M [ORNL; Webster, Clayton G [ORNL; Stoyanov, Miroslav K [ORNL; Bright, Eddie A [ORNL; Bhaduri, Budhendra L [ORNL

2013-01-01T23:59:59.000Z

4

DENSITY  

Science Conference Proceedings (OSTI)

... Table 2: Principal mineral phases found in the granite rock. Mineral phase. ... Table 4. Average density of 12 granite rocks by Archimedes and CT. ...

2007-01-08T23:59:59.000Z

5

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

E-Print Network (OSTI)

Peroxisome Proliferator-activated Receptor / Regulates Very Low Density Lipoprotein Production, Pennsylvania 16802 The results of recent studies using selective agonists for peroxisome proliferator-activated as well as lowered lipoprotein lipase activity in serum compared with wild-type controls. The latter

Omiecinski, Curtis

6

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)

is At the local level, the NRC Regulatory Staff has acceptedcriteria, if appropriate, NRC criteria for land use andPopulation Center Distance NRC Density Criteria Emergency

Nero, jA.V.

2010-01-01T23:59:59.000Z

7

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

SciTech Connect

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.

Fischer, M.

1998-07-01T23:59:59.000Z

8

Personal and environmental correlates of active travel and physical activity in a deprived urban population  

E-Print Network (OSTI)

assessment of the literature on the relationships among transportation, land use, and physical activity Washington, DC: Trans- portation Research Board and Institute of Medicine Committee on Physical Activity, Health, Transportation, and Land Use; 2004. 8...

Ogilvie, David; Mitchell, Richard; Mutrie, Nanette; Petticrew, Mark; Platt, Stephen

2008-08-27T23:59:59.000Z

9

Travel determinants and multi-scale transferability of national activity patterns to local populations  

Science Conference Proceedings (OSTI)

The ability to transfer national travel patterns to a local population is of interest when attempting to model megaregions or areas that exceed metropolitan planning organization (MPO) boundaries. At the core of this research are questions about the connection between travel behavior and land use, urban form, and accessibility. As a part of this process, a group of land use variables have been identified to define activity and travel patterns for individuals and households. The 2001 National Household Travel Survey (NHTS) participants are divided into categories comprised of a set of latent cluster models representing persons, travel, and land use. These are compared to two sets of cluster models constructed for two local travel surveys. Comparison of means statistical tests are used to assess differences among sociodemographic groups residing in localities with similar land uses. The results show that the NHTS and the local surveys share mean population activity and travel characteristics. However, these similarities mask behavioral heterogeneity that are shown when distributions of activity and travel behavior are examined. Therefore, data from a national household travel survey cannot be used to model local population travel characteristics if the goal to model the actual distributions and not mean travel behavior characteristics.

Henson, Kriste M [Los Alamos National Laboratory; Gou; ias, Konstadinos G [UCSB

2010-11-30T23:59:59.000Z

10

Carbon dioxide adsorption and activation on Ceria (110): A density functional theory study  

E-Print Network (OSTI)

Ceria (CeO2) is a promising catalyst for the reduction of carbon dioxide (CO2) to liquid fuels and commodity chemicals, in part because of its high oxygen storage capacity, yet the fundamentals of CO2 adsorption and initial activation on CeO2 surfaces remain largely unknown. We use density functional theory, corrected for onsite Coulombic interactions (DFT+U), to explore various adsorption sites and configurations for CO2 on stoichiometric and reduced CeO2 (110). Our model of reduced CeO2 (110) contains oxygen vacancies at the topmost atomic layer and undergoes surface reconstruction upon introduction of these vacancies. We find that CO2 adsorption on reduced CeO2 (110) is thermodynamically favored over the corresponding adsorption on stoichiometric CeO2 (110). The most stable adsorption configuration consists of CO2 adsorbed parallel to the reduced CeO2 (110) surface, with the molecule situated near the site of the oxygen vacancy. Structural changes in the CO2 molecule are also observed upon adsorption, so t...

Cheng, Zhuo; Lo, Cynthia S

2012-01-01T23:59:59.000Z

11

Predicting the Appraised Unit Value of Unimproved Parcels in San Francisco, CA Using LEED Sustainable Site Credit Criteria, Parcel area, Zoning, and Population Density  

E-Print Network (OSTI)

Nowadays many people recognize the need for sustainable development more than ever because of improper urban sprawl, rapid exhaustion of natural resources, and serious environmental problems. Emission of carbon dioxide from transportation sources causes severe air contamination, and this will increase due to the continued use of private vehicles. Thus, local governments are trying to keep public transit on a satisfactory level due to rising commuting time for cities. The U.S. Census shows that the majority of people would prefer to use their private automobile rather than utilize existing mass transit systems. Therefore, it is up to local governments to consider setting up more efficient alternative mass transit systems to deal with the increasing pollution caused by automobiles. Organizations adopt certain environmental standards for many different reasons, such as commitment to environmental issues affecting their industry. Other organizations could also benefit, both economically and environmentally, by utilizing such standards. The LEED (Leadership in Energy and Environmental Design) rating system is one of the more commonly-used environmental standards which presents guidelines for making decisions regarding land development while preserving the environment. However, only a few studies have attempted to evaluate this voluntary rating system which makes it difficult to justify the motivation of organizations that have adopted such voluntary standards. In this respect, this research primarily aims to explore the economic influence on the market value of undeveloped land through an analysis of public transportation in San Francisco, CA. Population density and area of each parcel are the factors considered to make the predictive model more powerful. Findings in this study show that LEED PTA (Public Transportation Accessibility) criteria, and population density significantly affect the appraised land unit value in specific purposed zones. Particularly, the economic impact of public transportation accessibility tended to be positive. With these findings, the statistical model for predicting land value was created. The result of this research can assist developers to make better site selections to accelerate the growth of sustainable construction.

Cho, Hyun Jeong

2011-08-01T23:59:59.000Z

12

Primary cell of high energy density in which the anode active material is an alkali metal  

Science Conference Proceedings (OSTI)

A primary cell of high specific energy in which the anode active material is an alkali metal and the cathode active material is sulphur oxychloride which simultaneously acts as an electrolyte solvent, said electrolyte further containing a dissolved salt and a co-solvent. The co-solvent is chosen from among phosphoryl chloride and benzoyl chloride; the dissolved salt is lithium tetrachloroaluminate.

Gabano, J.

1983-02-01T23:59:59.000Z

13

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

SciTech Connect

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.

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

2012-09-01T23:59:59.000Z

14

STELLAR POPULATIONS OF ULTRAVIOLET-SELECTED ACTIVE GALACTIC NUCLEI HOST GALAXIES AT z {approx} 2-3  

Science Conference Proceedings (OSTI)

We use stellar population synthesis modeling to analyze the host-galaxy properties of a sample of 33 UV-selected, narrow-lined active galactic nuclei (AGNs) at z {approx} 2-3. In order to quantify the contribution of AGN emission to host galaxy broadband spectral energy distributions (SEDs), we use the subsample of 11 AGNs with photometric coverage spanning from rest-frame UV through near-IR wavelengths. Modeling the SEDs of these objects with a linear combination of stellar population and AGN templates, we infer the effect of the AGN on derived stellar population parameters. We also estimate the typical bias in derived stellar populations for AGNs lacking rest-frame near-IR wavelength coverage, and develop a method for inferring the true host-galaxy properties. We compare AGN host-galaxy properties to those of a sample of UV-selected, star-forming non-AGNs in the same redshift range, including a subsample carefully matched in stellar mass. Although the AGNs have higher masses and star-formation rates than the full non-active sample, their stellar population properties are consistent with those of the mass-selected sample, suggesting that the presence of an AGN is not connected with the cessation of star formation activity in star-forming galaxies at z {approx} 2-3. We suggest that a correlation between M {sub BH} and galaxy stellar mass is already in place at this epoch. Assuming a roughly constant Eddington ratio for AGNs at all stellar masses, we are unable to detect the AGNs in low-mass galaxies because they are simply too faint.

Hainline, Kevin N.; Shapley, Alice E. [Department of Astronomy, University of California, Los Angeles, 430 Portola Plaza, Los Angeles, CA 90024 (United States); Greene, Jenny E. [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States); Steidel, Charles C. [Department of Astronomy, California Institute of Technology, MS 105-24, Pasadena, CA 91125 (United States); Reddy, Naveen A. [Department of Astronomy, University of California, Riverside, Riverside, CA 92521 (United States); Erb, Dawn K. [Department of Physics, University of Wisconsin-Milwaukee, Milwaukee, WI 53201 (United States)

2012-11-20T23:59:59.000Z

15

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

E-Print Network (OSTI)

://www.ijbnpa.org/content/10/1/76factor surveillance system, 2001. Prev Chronic Dis: public health res, practice, and policy 2005, 2(2):1–10. 14. Craig R, Mindell J, Hirani V: Health survey for England 2008: physical activity and fitness. Leeds: NHS Information Centre...

Humphreys, David K; Ogilvie, David

2013-06-15T23:59:59.000Z

16

Evolution of the Population of Precipitating Convective Systems over the Equatorial Indian Ocean in Active Phases of the Madden–Julian Oscillation  

Science Conference Proceedings (OSTI)

Three-dimensional radar reflectivity fields from a dual-wavelength Doppler polarimetric radar (S-PolKa) deployed in the equatorial Indian Ocean are used to evaluate the composition of the population of convective cloud elements during active ...

Manuel D. Zuluaga; Robert A. Houze Jr.

2013-09-01T23:59:59.000Z

17

Evolution of the Population of Precipitating Convective Systems over the Equatorial Indian Ocean in Active Phases of the Madden-Julian Oscillation  

Science Conference Proceedings (OSTI)

Three-dimensional radar-reflectivity fields from a dual-wavelength Doppler polarimetric radar (S-PolKa) deployed in the equatorial Indian Ocean are used to evaluate the composition of the population of convective cloud elements during active ...

Manuel D. Zuluaga; Robert A. Houze; Jr.

18

Anomalous evolution of Ar metastable density with electron density in high density Ar discharge  

SciTech Connect

Recently, an anomalous evolution of argon metastable density with plasma discharge power (electron density) was reported [A. M. Daltrini, S. A. Moshkalev, T. J. Morgan, R. B. Piejak, and W. G. Graham, Appl. Phys. Lett. 92, 061504 (2008)]. Although the importance of the metastable atom and its density has been reported in a lot of literature, however, a basic physics behind the anomalous evolution of metastable density has not been clearly understood yet. In this study, we investigated a simple global model to elucidate the underlying physics of the anomalous evolution of argon metastable density with the electron density. On the basis of the proposed simple model, we reproduced the anomalous evolution of the metastable density and disclosed the detailed physics for the anomalous result. Drastic changes of dominant mechanisms for the population and depopulation processes of Ar metastable atoms with electron density, which take place even in relatively low electron density regime, is the clue to understand the result.

Park, Min; Chang, Hong-Young [Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon 305-701 (Korea, Republic of); You, Shin-Jae; Kim, Jung-Hyung [Center for Vacuum Technology, Korea Research Institute of Standards and Science, Daejeon, 305-306 (Korea, Republic of); Shin, Yong-Hyeon

2011-10-15T23:59:59.000Z

19

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)

Standards for Nuclear Power Plants," by A.V. Nero and Y.C.Response Planning for Nuclear Power Plants in California,"Densities Surrounding Nuclear Power Plants," by A.V. Nero,

Nero, jA.V.

2010-01-01T23:59:59.000Z

20

Density Functional Theory and Molecular Dynamics Studies on Energetics and Kinetics for Electro-Active Polymers: PVDF and P(VDF-TrFE)  

E-Print Network (OSTI)

We use first principles methods to study static and dynamical mechanical properties of the ferroelectric polymer Poly(vinylidene fluoride) (PVDF) and its copolymer with trifluoro ethylene (TrFE). We use density functional theory [within the generalized gradient approximation (DFT-GGA)] to calculate structures and energetics for various crystalline phases for PVDF and P(VDF-TrFE). We find that the lowest energy phase for PVDF is a non-polar crystal with a combination of trans (T) and gauche (G) bonds; in the case of the copolymer the role of the extra (bulkier) F atoms is to stabilize T bonds. This leads to the higher crystallinity and piezoelectricity observed experimentally. Using the MSXX first principles-based force field (FF) with molecular dynamics (MD), we find that the energy barrier necessary to nucleate a kink (gauche pairs separated by trans bonds) in an all-T crystal is much lower (14.9 kcal/mol) in P(VDF-TrFE) copolymer than in PVDF (24.8 kcal/mol). This correlates with the observation that the polar phase of the copolymer exhibits a solid-solid a transition to a non-polar phase under heating while PVDF directly melts. We also studied the mobility of an interface between a polar and non-polar phases under uniaxial stress; we find a lower threshold stress and a higher mobility in the copolymer as compared with PVDF. Finally, considering plastic deformation under applied shear, we find that the chains for P(VDF-TrFE) have a very low resistance to sliding, particularly along the chain direction. The atomistic characterization of these "unit mechanisms" provides essential input to mesoscopic or macroscopic models of electro-active polymers.

H. B. Su; Alejandro Strachan; William A. Goddard III

2004-08-09T23:59:59.000Z

Note: This page contains sample records for the topic "activity population density" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


21

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  

Science Conference Proceedings (OSTI)

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.

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

22

Density Log | Open Energy Information  

Open Energy Info (EERE)

Density Log Density Log Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Technique: Density Log Details Activities (6) Areas (6) Regions (0) NEPA(0) Exploration Technique Information Exploration Group: Downhole Techniques Exploration Sub Group: Well Log Techniques Parent Exploration Technique: Well Log Techniques Information Provided by Technique Lithology: provides data on the bulk density of the rock surrounding the well Stratigraphic/Structural: Stratigraphic correlation between well bores. Hydrological: Porosity of the formations loggesd can be calculated for the Density log andprovide an indication potential aquifers. Thermal: Cost Information Low-End Estimate (USD): 0.4040 centUSD 4.0e-4 kUSD 4.0e-7 MUSD 4.0e-10 TUSD / foot Median Estimate (USD): 0.6868 centUSD

23

Scattering Length Density Calculator  

Science Conference Proceedings (OSTI)

... For energy dependent cross sections please go to ... The neutron scattering length density is defined ... To calculate scattering length densities enter a ...

24

On the Absence of Population Bias in the Tornado Climatology of Southwestern Ontario  

Science Conference Proceedings (OSTI)

Rural population densities and tornado incidence (confirmed and probable categories) are compared for noncoastal regions in the southwestern Ontario peninsula. No apparent relationship is found between rural population density and F0–F4 ...

Patrick King

1997-12-01T23:59:59.000Z

25

Variability of Population-Weighted Seasonal Heating Degree Days  

Science Conference Proceedings (OSTI)

Regional and national heating fuel demand is related to both weather and population density. This study analyzes the variability of population-weighted, seasonal heating degree days for the coterminous 48 states. A risk assessment of unusual ...

Nathaniel B. Guttman

1983-03-01T23:59:59.000Z

26

Estimated population near uranium tailings  

SciTech Connect

Population studies, which took place during the months of April, May, and June 1983, were performed for 27 active and 25 inactive mill sites. For each mill site, a table showing population by radius (1/2, 1, 2, 3, 4, and 5 km) in 16 compass directions was generated. 22 references, 6 tables.

Bloomster, C.H.; Brown, D.R.; Bruno, G.A.; Craig, S.N.; Dirks, J.A.; Griffin, E.A.; Reis, J.W.; Young, J.K.

1984-01-01T23:59:59.000Z

27

Rock Density | Open Energy Information  

Open Energy Info (EERE)

form form View source History View New Pages Recent Changes All Special Pages Semantic Search/Querying Get Involved Help Apps Datasets Community Login | Sign Up Search Page Edit with form History Facebook icon Twitter icon » Rock Density Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Technique: Rock Density Details Activities (2) Areas (2) Regions (0) NEPA(0) Exploration Technique Information Exploration Group: Lab Analysis Techniques Exploration Sub Group: Rock Lab Analysis Parent Exploration Technique: Rock Lab Analysis Information Provided by Technique Lithology: Density of different lithologic units. Stratigraphic/Structural: Hydrological: Thermal: Cost Information Low-End Estimate (USD): 10.001,000 centUSD 0.01 kUSD 1.0e-5 MUSD 1.0e-8 TUSD / sample

28

Separation of carbon nanotubes in density gradients  

DOE Patents (OSTI)

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.

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

2012-02-07T23:59:59.000Z

29

Separation of carbon nanotubes in density gradients  

DOE Patents (OSTI)

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.

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

2010-02-16T23:59:59.000Z

30

Density-dependent covariant energy density functionals  

Science Conference Proceedings (OSTI)

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.

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

2012-10-20T23:59:59.000Z

31

Rock Density At Silver Peak Area (DOE GTP) | Open Energy Information  

Open Energy Info (EERE)

Density At Silver Peak Area (DOE GTP) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Rock Density At Silver Peak Area (DOE GTP) Exploration...

32

Density Log at Fort Bliss Area (DOE GTP) | Open Energy Information  

Open Energy Info (EERE)

Density Log at Fort Bliss Area (DOE GTP) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Density Log at Fort Bliss Area (DOE GTP) Exploration...

33

Family and home correlates of children's physical activity in a multi-ethnic population: the cross-sectional Child Heart and Health Study in England (CHASE)  

E-Print Network (OSTI)

J Griffin1, Derek G Cook2, Chris G Owen2, Alicja R Rudnicka2, Peter H Whincup2 Abstract Background: The influence of the family and home environment on childhood physical activity (PA) and whether this differs between ethnic groups remains uncertain... and implications. Edited by: Biddle S, Sallis J, Cavill N. London: Health Education Authority; 1998:49-68. 5. Parfitt G, Pavey T, Rowlands AV: Children’s physical activity and psychological health: the relevance of intensity. Acta Paediatr 2009, 98(6):1037-1043. 6...

McMinn, Alison M; van Sluijs, Esther M F; Nightingale, Claire M; Griffin, Simon J; Cook, Derek G; Owen, Chris G; Rudnicka, Alicja R; Whincup, Peter H

2011-02-15T23:59:59.000Z

34

First-Principles Density Functional Theory Study of Grain Boundary ...  

Science Conference Proceedings (OSTI)

Presentation Title, First-Principles Density Functional Theory Study of Grain ... It was found that both the vacancy formation energy and diffusion activation ...

35

activities  

NLE Websites -- All DOE Office Websites (Extended Search)

Detecting Things We Cannot See: Learning the Concepts of Control and Detecting Things We Cannot See: Learning the Concepts of Control and Variable in an Experiment Submitted by Anita Brook-Dupree, 1996 TRAC teacher at Fermilab, Teacher, Alternative Middle Years School, Philadelphia, PA. Particle physicists at Fermilab in Batavia, Illinois are faced with the problem of detecting the presence of sub-atomic particles they cannot see. During my summer as a TRAC teacher at Fermilab, I tried to think of ways to teach middle school students about things we cannot see. I want to thank my nine-year-old daughter Gia for the idea for the following activity. I was lamenting that I could not come up with ideas of how to relate the work of Fermilab scientists to anything that my students would understand. Then I was reminded by my daughter, that when I brought her to school on the

36

DENSITY CONTROL IN A REACTOR  

DOE Patents (OSTI)

A reactor is described in which natural-uranium bodies are located in parallel channels which extend through the graphite mass in a regular lattice. The graphite mass has additional channels that are out of the lattice and contain no uranium. These additional channels decrease in number per unit volume of graphite from the center of the reactor to the exterior and have the effect of reducing the density of the graphite more at the center than at the exterior, thereby spreading neutron activity throughout the reactor. (AEC)

Marshall, J. Jr.

1961-10-24T23:59:59.000Z

37

Density | OpenEI  

Open Energy Info (EERE)

Density Density Dataset Summary Description This dataset is part of a larger internal dataset at the National Renewable Energy Laboratory (NREL) that explores various characteristics of large solar electric (both PV and CSP) facilities around the United States. This dataset focuses on the land use characteristics for solar facilities that are either under construction or currently in operation. Source Land-Use Requirements for Solar Power Plants in the United States Date Released June 25th, 2013 (5 months ago) Date Updated Unknown Keywords acres area average concentrating solar power csp Density electric hectares km2 land land requirements land use land-use mean photovoltaic photovoltaics PV solar statistics Data application/vnd.openxmlformats-officedocument.spreadsheetml.sheet icon Master Solar Land Use Spreadsheet (xlsx, 1.5 MiB)

38

Single-Nucleon Densities  

NLE Websites -- All DOE Office Websites (Extended Search)

Densities Densities This web page presents single-nucleon densities calculated for a variety of nuclei in the range A=2-10 with some preliminary results for A=11,12. These are from variational Monte Carlo calculations (VMC) using the Argonne v18 two-nucleon and Urbana X three-nucleon potentials (AV18+UX). (Urbana X is intermediate between the Urbana IX and Illinois-7 models; it has the form of UIX supplemented with a two-pion S-wave piece, while the strengths of its terms are taken from the IL7 model. It does NOT have the three-pion-ring term of IL7.) These VMC wave functions are the starting trial functions for a number of recent Green's function Monte Carlo (GFMC) calculations: Brida, et al., Phys. Rev. C 84, 024319 (2011); McCutchan, et al., Phys. Rev. C 86, 024315 (2012);

39

Rock Density At Alum Area (DOE GTP) | Open Energy Information  

Open Energy Info (EERE)

Rock Density At Alum Area (DOE GTP) Rock Density At Alum Area (DOE GTP) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Rock Density At Alum Geothermal Area (DOE GTP) Exploration Activity Details Location Alum Geothermal Area Exploration Technique Rock Density Activity Date Usefulness not indicated DOE-funding Unknown References (1 January 2011) GTP ARRA Spreadsheet Retrieved from "http://en.openei.org/w/index.php?title=Rock_Density_At_Alum_Area_(DOE_GTP)&oldid=402985" Categories: Exploration Activities DOE Funded Activities ARRA Funded Activities What links here Related changes Special pages Printable version Permanent link Browse properties About us Disclaimers Energy blogs Linked Data Developer services OpenEI partners with a broad range of international organizations to grow

40

Multiple density layered insulator  

DOE Patents (OSTI)

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.

Alger, T.W.

1994-09-06T23:59:59.000Z

Note: This page contains sample records for the topic "activity population density" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


41

Multiple density layered insulator  

DOE Patents (OSTI)

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.

Alger, Terry W. (Tracy, CA)

1994-01-01T23:59:59.000Z

42

Local Atomic Density of Microporous Carbons  

DOE Green Energy (OSTI)

We investigated the structure of two disordered carbons: activated carbon fibers (ACF) and ultramicroporous carbon (UMC). These carbons have highly porous structure with large surface areas and consequently low macroscopic density that should enhance adsorption of hydrogen. We used the atomic pair distribution function to probe the local atomic arrangements. The results show that the carbons maintain an in-plane local atomic structure similar to regular graphite, but the stacking of graphitic layers is strongly disordered. Although the local atomic density of these carbons is lower than graphite, it is only {approx}20% lower and is much higher than the macroscopic density due to the porosity of the structure. For this reason, the density of graphene sheets that have optimum separation for hydrogen adsorption is lower than anticipated.

Dmowski, Wojtek; Contescu, Cristian I.; Llobet, Anna; Gallego, Nidia C.; Egami, Takeskhi (Tennessee-K); (ORNL); (LANL)

2012-07-12T23:59:59.000Z

43

The Decreasing Population Bias in Tornado Reports across the Central Plains  

Science Conference Proceedings (OSTI)

Tornado–hazard assessment is hampered by a population bias in the available data. Here, the authors demonstrate a way to statistically quantify this bias using the ratio of city to country report densities. The expected report densities come from ...

James B. Elsner; Laura E. Michaels; Kelsey N. Scheitlin; Ian J. Elsner

2013-07-01T23:59:59.000Z

44

Using Density Equalizing Map Projection (DEMP) in Epidemiologic  

NLE Websites -- All DOE Office Websites (Extended Search)

Using Density Equalizing Map Projection (DEMP) in Epidemiologic Using Density Equalizing Map Projection (DEMP) in Epidemiologic Surveillance: An Analysis of Female Breast Cancer Incidence in the San Francisco Bay Area Speaker(s): Christine Erdman Date: April 5, 2001 - 12:00pm Location: Bldg. 90 Seminar Host/Point of Contact: David Faulkner This study examined the spatial distribution of female breast cancer incidence in the San Francisco Bay Area (California, U.S.A.) in relation to various demographic variables using cartograms for control of population density. Using a cartogram technique known as density equalized map projection (DEMP), census tract boundaries of geopolitical maps are transformed such that the resultant census tract areas are proportional to their population at risk. With spatial confounding removed, the maps become

45

Probability density function method for variable-density pressure-gradient-driven turbulence and mixing  

SciTech Connect

Probability density function (PDF) methods are extended to variable-density pressure-gradient-driven turbulence. We apply the new method to compute the joint PDF of density and velocity in a non-premixed binary mixture of different-density molecularly mixing fluids under gravity. The full time-evolution of the joint PDF is captured in the highly non-equilibrium flow: starting from a quiescent state, transitioning to fully developed turbulence and finally dissipated by molecular diffusion. High-Atwood-number effects (as distinguished from the Boussinesq case) are accounted for: both hydrodynamic turbulence and material mixing are treated at arbitrary density ratios, with the specific volume, mass flux and all their correlations in closed form. An extension of the generalized Langevin model, originally developed for the Lagrangian fluid particle velocity in constant-density shear-driven turbulence, is constructed for variable-density pressure-gradient-driven flows. The persistent small-scale anisotropy, a fundamentally 'non-Kolmogorovian' feature of flows under external acceleration forces, is captured by a tensorial diffusion term based on the external body force. The material mixing model for the fluid density, an active scalar, is developed based on the beta distribution. The beta-PDF is shown to be capable of capturing the mixing asymmetry and that it can accurately represent the density through transition, in fully developed turbulence and in the decay process. The joint model for hydrodynamics and active material mixing yields a time-accurate evolution of the turbulent kinetic energy and Reynolds stress anisotropy without resorting to gradient diffusion hypotheses, and represents the mixing state by the density PDF itself, eliminating the need for dubious mixing measures. Direct numerical simulations of the homogeneous Rayleigh-Taylor instability are used for model validation.

Bakosi, Jozsef [Los Alamos National Laboratory; Ristorcelli, Raymond J [Los Alamos National Laboratory

2010-01-01T23:59:59.000Z

46

High Energy Density Capacitors  

SciTech Connect

BEEST Project: Recapping is developing a capacitor that could rival the energy storage potential and price of today’s 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.

None

2010-07-01T23:59:59.000Z

47

Density Log at Silver Peak Area (DOE GTP) | Open Energy Information  

Open Energy Info (EERE)

Silver Peak Area (DOE GTP) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Density Log at Silver Peak Area (DOE GTP) Exploration Activity Details...

48

Density Log at Gabbs Valley Area (DOE GTP) | Open Energy Information  

Open Energy Info (EERE)

Gabbs Valley Area (DOE GTP) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Density Log at Gabbs Valley Area (DOE GTP) Exploration Activity...

49

NEUTRON DENSITY CONTROL IN A NEUTRONIC REACTOR  

DOE Patents (OSTI)

The method and means for controlling the neutron density in a nuclear reactor is described. It describes the method and means for flattening the neutron density distribution curve across the reactor by spacing the absorbing control members to varying depths in the central region closer to the center than to the periphery of the active portion of the reactor to provide a smaller neutron reproduction ratio in the region wherein the members are inserted, than in the remainder of the reactor thereby increasing the over-all potential power output.

Young, G.J.

1959-06-30T23:59:59.000Z

50

Numerical calculation of the moments of the population balance equation  

Science Conference Proceedings (OSTI)

The combined CFD-PBM (population balance models) are computationally intensive, so a possibility is to calculate only a few moments of the probability density function (PDF) of the PBM minimizing the computational costs. However, this formulation results ... Keywords: least squares method, population balance equation, quadrature approximation

C. A. Dorao; H. A. Jakobsen

2006-11-01T23:59:59.000Z

51

Charge Density Wave Compounds  

NLE Websites -- All DOE Office Websites (Extended Search)

Fisher Research Group Fisher Research Group Layered Chalcogenides 29 February 2008 Controlling the Wave by Brad Plummer, SLAC Communications Stanford University researchers working in part at SSRL have discovered a novel set of properties pertaining to a compound of materials called tritellurides. These compounds, composed of three atoms of tellurium and a single atom of one of the rare earth elements, demonstrate unique electronic properties that can be controlled by altering the temperature of the material. The tritellurides display phenomena known as charge density waves (CDW). In a normal conductive metal, electrons persist in a "sea" wherein they are evenly distributed and equally available, or conductive. A CDW occurs under certain circumstances and causes the electrons to clump together, lowering their availability, and thereby lowering the compound's conductivity. Tellurium, when crystallized into quasi-two-dimensional planes and combined with rare earth elements, produces a material with CDWs that can be manipulated and controlled.

52

Low density microcellular foams  

DOE Patents (OSTI)

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.

LeMay, James D. (Castro Valley, CA)

1992-01-01T23:59:59.000Z

53

Low density microcellular foams  

DOE Patents (OSTI)

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.

LeMay, James D. (Castro Valley, CA)

1991-01-01T23:59:59.000Z

54

Density Coordinate Mixed Layer Models  

Science Conference Proceedings (OSTI)

The development of mixed layer models in so-called density coordinates is discussed. Density coordinates, or isopycnal coordinates as they are sometimes called, are becoming increasingly popular for use in ocean models due to their highly ...

William K. Dewar

2001-02-01T23:59:59.000Z

55

Expulsion of Symbiotic Algae during Feeding by the Green Hydra – a Mechanism for Regulating Symbiont Density?  

E-Print Network (OSTI)

Background: Algal-cnidarian symbiosis is one of the main factors contributing to the success of cnidarians, and is crucial for the maintenance of coral reefs. While loss of the symbionts (such as in coral bleaching) may cause the death of the cnidarian host, over-proliferation of the algae may also harm the host. Thus, there is a need for the host to regulate the population density of its symbionts. In the green hydra, Chlorohydra viridissima, the density of symbiotic algae may be controlled through host modulation of the algal cell cycle. Alternatively, Chlorohydra may actively expel their endosymbionts, although this phenomenon has only been observed under experimentally contrived stress conditions. Principal Findings: We show, using light and electron microscopy, that Chlorohydra actively expel endosymbiotic algal cells during predatory feeding on Artemia. This expulsion occurs as part of the apocrine mode of secretion from the endodermal digestive cells, but may also occur via an independent exocytotic mechanism. Significance: Our results demonstrate, for the first time, active expulsion of endosymbiotic algae from cnidarians under natural conditions. We suggest this phenomenon may represent a mechanism whereby cnidarians can expel excess symbiotic algae when an alternative form of nutrition is available in the form of prey.

Yelena Fishman; Eliahu Zlotkin; Daniel Sher

2007-01-01T23:59:59.000Z

56

Density rise experiment on PLT  

SciTech Connect

The evolution of the density profile in PLT during intense gas puffing is documented and analyzed. Measurements of the spectrum of low energy edge neutrals and of the change in central neutral density indicate that charge-exchange processes alone cannot account for the central density rise. The transient density profile changes can be reproduced numerically by a diffusivity of approx. 10/sup 4/ cm/sup 2//s, and a spatially averaged inward flow of 10/sup 3/ cm/s. These transport coefficients are 10 ..-->.. 10/sup 2/ times larger than neoclassical. The ion energy confinement is reduced, the small scale density fluctuations are increased, and runaway electrons losses are increased during the density rise.

Strachan, J.D.; Bretz, N.; Mazzucato, E.

1982-05-01T23:59:59.000Z

57

Energy Densities for LLNL EMB  

Summary of Projected Power and Energy Density Parameters for the “New Generation” LLNL Electromechanical Batteries R.F. Post June 24, 2013

58

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

Science Conference Proceedings (OSTI)

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.

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

59

Population | OpenEI  

Open Energy Info (EERE)

Population Population Dataset Summary Description Total population (in millions) by country, 1980 to 2010. Compiled by Energy Information Administration (EIA). Source EIA Date Released Unknown Date Updated Unknown Keywords EIA Population world Data text/csv icon population_by_country_1980_2010millions.csv (csv, 59.1 KiB) Quality Metrics Level of Review Peer Reviewed Comment Temporal and Spatial Coverage Frequency Time Period 1980 - 2010 License License Other or unspecified, see optional comment below Comment Rate this dataset Usefulness of the metadata Average vote Your vote Usefulness of the dataset Average vote Your vote Ease of access Average vote Your vote Overall rating Average vote Your vote Comments Login or register to post comments If you rate this dataset, your published comment will include your rating.

60

Density-based logistic regression  

Science Conference Proceedings (OSTI)

This paper introduces a nonlinear logistic regression model for classification. The main idea is to map the data to a feature space based on kernel density estimation. A discriminative model is then learned to optimize the feature weights as well as ... Keywords: density estimation, logistic regression, medical prediction, nonlinear classification

Wenlin Chen, Yixin Chen, Yi Mao, Baolong Guo

2013-08-01T23:59:59.000Z

Note: This page contains sample records for the topic "activity population density" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


61

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

Science Conference Proceedings (OSTI)

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).

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

2011-09-15T23:59:59.000Z

62

Population and Environment  

E-Print Network (OSTI)

. . . . . . . . . . . . . . . . . . . . . 356 Coastal and Marine Environments . . . . . . . . . . . . . . . . . 358 Energy, Air Pollution or growth. Indeed, an overlay of graphs depicting global trends in population, energy consumption, carbon; coastal and marine environments; and energy, air pollu- tion, and climate change. In the concluding

63

Low density carbonized composite foams  

DOE Patents (OSTI)

A carbonized composite foam having a density less than about 50 mg/cm{sup 3} and individual cell sizes no greater than about 1 {mu}m in diameter is described, and the process of making it. 3 figs.

Kong, Fung-Ming.

1989-12-07T23:59:59.000Z

64

Quarkonium at nonzero isospin density  

E-Print Network (OSTI)

We calculate the energies of quarkonium bound states in the presence of a medium of nonzero isospin density using lattice QCD. The medium, created using a canonical (fixed isospin charge) approach, induces a reduction of ...

Detmold, William

65

Observation of inverted population levels in the FM-1 Spherator  

DOE Green Energy (OSTI)

Inversions in the populations of excited levels in hydrogen and HeII were observed in the FM-1 Spherator. The inversion increases strongly as the ratio of the decay time of the electron temperature to the decay time of the electron density was decreased. Time dependent numerical calculations of the populations were in good agreement with the experimental measurements. More general calculations for high Z hydrogen-like ions are discussed.

Suckewer, S.; Hawryluk, R. J.; Okabayashi, M.; Schmidt, J. A.

1976-04-01T23:59:59.000Z

66

Carbonate fuel cell monolith design for high power density and low cost  

SciTech Connect

Objective is higher power density operation and cost reduction. This is accomplished by the design of a bipolar plate where the separate corrugated current collectors are eliminated; cost reduction was also derived through higher power density and reduced material usage. The higher volumetric power density operation was achieved through lower cell resistance, increased active component surface area, and reduced cell height.

Allen, J.; Doyon, J.

1996-08-01T23:59:59.000Z

67

Lipoprotein subclass analysis by immunospecific density  

E-Print Network (OSTI)

Apolipoprotein C-1 (apo C-1) enriched HDL has been described as an atherogenic form of HDL associated with an increased risk for cardiovascular disease (CVD). The objective of the present study was to develop a rapid method for the separation, purification, and characterization of Apo C-1 from serum. We isolated and characterize HDL subclasses from individuals with and without angiographically-proven CVD who have elevated and normal-to-low HDL-C levels. Ultracentrifugation was linked with immunoaffinity separations for the specific separation of Apo C-1 enriched HDL from other lipoproteins. A 50 ?L sample of serum is diluted in TRIS HCl buffer (pH 7.5) and incubated with CNBr-activated Sepharose (Amersham) containing antibodies to apo C-1 (Academy Bio-medical Company). The apo C-1-depleted serum is removed by centrifugation and all apo C-1-containing lipoproteins are released from the Sepharose beads at pH 2. The apo C-1-depleted sample and the apo C-1-containing sample were ultracentrifuged to obtain a lipoprotein density profile in the absence and presence of apo C-1. Density Lipoprotein Profiling (DLP) gives relevant information of lipoproteins, such as density and subclass characterization, and is a novel approach to purify apo C-1-enriched HDL. An additional advantage of this approach is that lipoprotein-a (Lp(a)), which is often an interfering component in the HDL density region, is eliminated. Results show feasibility that these methods could be used in a clinical setting, was achieved. This measurement may yield a precise and quantitative profile of the distribution of apo C-1 for all lipoprotein particles including HDL.

Lester, Sandy Marie

2008-12-01T23:59:59.000Z

68

Nevada Test Site tortoise population monitoring study. Final report  

Science Conference Proceedings (OSTI)

A Tortoise Population Monitoring Study was initiated to determine and monitor the density of desert tortoises (Gopherus agassizii) on the Nevada Test Site. Quadrat sampling was conducted following methodology described in the Draft Desert Tortoise Recovery Plan (FWS, 1993). So few tortoises were found that densities could not be calculated. Based on estimates of capture probabilities and densities from other studies, it was determined that 1-km{sup 2} (0.4 mi{sup 2}) plots did not contain enough tortoises for estimating densities with the Recovery Plan methods. It was recommended that additional surveys on the Nevada Test Site using those methods not be conducted. Any future efforts to monitor desert tortoise densities should start by identifying other possible methods, determining their relative power to detect changes, and estimating their cost.

Mueller, J.M.; Zander, K.K.

1994-12-01T23:59:59.000Z

69

Plasma digital density determining device  

DOE Patents (OSTI)

The density of a decaying plasma in an electrically conducting enclosure is determined by applying an excitation to the cavity formed by the enclosure and counting digitally the number of resonant frequencies traversed by the combination of the cavity and the decaying plasma.

Sprott, Julien C. (Madison, WI); Lovell, Thomas W. (Madison, WI); Holly, Donald J. (Madison, WI)

1976-01-01T23:59:59.000Z

70

3-D Density Model Of Mt Etna Volcano (Southern Italy) | Open Energy  

Open Energy Info (EERE)

3-D Density Model Of Mt Etna Volcano (Southern Italy) 3-D Density Model Of Mt Etna Volcano (Southern Italy) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: 3-D Density Model Of Mt Etna Volcano (Southern Italy) Details Activities (0) Areas (0) Regions (0) Abstract: A detailed density model of Mt. Etna and its surrounding areas has been evaluated using a 3-D inversion of the gravimetric data acquired in the 1980's. Several high-density and low-density bodies are found, penetrating from shallow depths as far down as 12 km bsl. A positive correlation (in terms of location, extent, density, and velocity) is established between several anomalies of the density model and features identified in previously published seismic tomographies. A prominent high-density body extending down to 7 km bsl is recognized in the southern

71

High-Activity Dealloyed Catalysts  

NLE Websites -- All DOE Office Websites (Extended Search)

2 fuel cells - Demonstrate durability of the kinetic mass activity against DOE- specified voltage cycling tests in fuel cells - Achieve high current density performance in H 2 air...

72

Building a Universal Nuclear Energy Density Functional  

NLE Websites -- All DOE Office Websites (Extended Search)

Building a Universal Nuclear Energy Density Functional Building a Universal Nuclear Energy Density Functional VaryMatrix.png Collaboration with mathematicians and computational...

73

Definition: Density Log | Open Energy Information  

Open Energy Info (EERE)

Density Log Density Log Jump to: navigation, search Dictionary.png Density Log Density logging is a well logging tool that can provide a continuous record of a formation's bulk density along the length of a borehole. In geology, bulk density is a function of the density of the minerals forming a rock (i.e. matrix) and the fluid enclosed in the pore spaces.[1] View on Wikipedia Wikipedia Definition Density logging is a well logging tool that can provide a continuous record of a formation's bulk density along the length of a borehole. In geology, bulk density is a function of the density of the minerals forming a rock and the fluid enclosed in the pore spaces. This is one of three well logging tools that are commonly used to calculate porosity, the other two being sonic logging and neutron porosity logging

74

Windows activation Sergei Striganov  

E-Print Network (OSTI)

Windows activation Sergei Striganov Fermilab July 25, 2007 #12;Beam windows residual activity of irradiated object should be much larger than -ray interaction length (3.7 cm in windows). In such model activation is proportional to star density. For beam size much smaller windows transverse dimension

McDonald, Kirk

75

Probability Densities in Strong Turbulence  

E-Print Network (OSTI)

According to modern developments in turbulence theory, the "dissipation" scales (u.v. cut-offs) $\\eta$ form a random field related to velocity increments $\\delta_{\\eta}u$. In this work we, using Mellin's transform combined with the Gaussain large -scale boundary condition, calculate probability densities (PDFs) of velocity increments $P(\\delta_{r}u,r)$ and the PDF of the dissipation scales $Q(\\eta, Re)$, where $Re$ is the large-scale Reynolds number. The resulting expressions strongly deviate from the Log-normal PDF $P_{L}(\\delta_{r}u,r)$ often quoted in the literature. It is shown that the probability density of the small-scale velocity fluctuations includes information about the large (integral) scale dynamics which is responsible for deviation of $P(\\delta_{r}u,r)$ from $P_{L}(\\delta_{r}u,r)$. A framework for evaluation of the PDFs of various turbulence characteristics involving spatial derivatives is developed. The exact relation, free of spurious Logarithms recently discussed in Frisch et al (J. Fluid Mech. {\\bf 542}, 97 (2005)), for the multifractal probability density of velocity increments, not based on the steepest descent evaluation of the integrals is obtained and the calculated function $D(h)$ is close to experimental data. A novel derivation (Polyakov, 2005), of a well-known result of the multi-fractal theory [Frisch, "Turbulence. {\\it Legacy of A.N.Kolmogorov}", Cambridge University Press, 1995)), based on the concepts described in this paper, is also presented.

Victor Yakhot

2005-12-12T23:59:59.000Z

76

Density estimation for data with rounding errors  

Science Conference Proceedings (OSTI)

Rounding of data is common in practice. The problem of estimating the underlying density function based on data with rounding errors is addressed. A parametric maximum likelihood estimator and a nonparametric bootstrap kernel density estimator are proposed. ... Keywords: Bootstrapping, Deconvolution density estimation, Fast Fourier transformation, Kernel density estimation, Measurement error

B. Wang, W. Wertelecki

2013-09-01T23:59:59.000Z

77

Activities of the High Energy Density Laboratory Plasmas  

E-Print Network (OSTI)

3-4, 2008 Livermore, CA on behalf of the HEDLP FESAC subpanel #12;"joint HEDLP program [OFES+NNSA and 28 contributed talks M. Donovan (NNSA) NNSA perspective G. Nardella (OFES) OFES perspective HEDLP #12;IFE HEDLP science: conventional and alternative concepts · Conventional ICF (NNSA funded

78

Population Monte Carlo algorithms  

E-Print Network (OSTI)

We give a cross-disciplinary survey on ``population'' Monte Carlo algorithms. In these algorithms, a set of ``walkers'' or ``particles'' is used as a representation of a high-dimensional vector. The computation is carried out by a random walk and split/deletion of these objects. The algorithms are developed in various fields in physics and statistical sciences and called by lots of different terms -- ``quantum Monte Carlo'', ``transfer-matrix Monte Carlo'', ``Monte Carlo filter (particle filter)'',``sequential Monte Carlo'' and ``PERM'' etc. Here we discuss them in a coherent framework. We also touch on related algorithms -- genetic algorithms and annealed importance sampling.

Yukito IBA

2000-08-16T23:59:59.000Z

79

A HMM-based hierarchical framework for long-term population projection of small areas  

Science Conference Proceedings (OSTI)

Population Projection is the numerical outcome of a specific set of assumptions about future population changes. It is indispensable to the planning of sites as almost all successive planning activities such as the identification of land and housing ...

Bin Jiang; Huidong Jin; Nianjun Liu; Mike Quirk; Ben Searle

2007-12-01T23:59:59.000Z

80

Cultural Dasymetric Population Mapping with Historical GIS: A Case Study from the Southern Appalachians  

Science Conference Proceedings (OSTI)

There has been a recent flurry of interest in dasymetric population mapping. However, the ancillary coverages that underlie current dasymetric methods are unconnected to cultural context. The resulting regions may indicate density patterns, but not necessarily ... Keywords: Agricultural Geography, Appalachia, Dasymetric, Historical GIS, Population Mapping, Rural Geography, West Virginia

George Towers

2011-10-01T23:59:59.000Z

Note: This page contains sample records for the topic "activity population density" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


81

Definition: Power density | Open Energy Information  

Open Energy Info (EERE)

density density Jump to: navigation, search Dictionary.png Power density The rate of energy flow (power) per unit volume, area or mass. Common metrics include: horsepower per cubic inch, watts per square meter and watts per kilogram.[1][2] View on Wikipedia Wikipedia Definition Power density (or volume power density or volume specific power) is the amount of power (time rate of energy transfer) per unit volume. In energy transformers like batteries, fuel cells, motors, etc. but also power supply units or similar, power density refers to a volume. It is then also called volume power density which is expressed as W/m. Volume power density is sometimes an important consideration where space is constrained. In reciprocated internal combustion engines, power density- power per swept

82

Phase diagram of amorphous solid water: Low-density, high-density, and very-high-density amorphous ices  

E-Print Network (OSTI)

for the understanding of the transformation between the different amorphous ices and the two hypothesized phasesPhase diagram of amorphous solid water: Low-density, high-density, and very-high-density amorphous ices Nicolas Giovambattista,1,2 H. Eugene Stanley,2 and Francesco Sciortino3 1 Department of Chemical

Sciortino, Francesco

83

Effects of Vegetation Structure and Elevation on Lower Keys Marsh Rabbit Density  

E-Print Network (OSTI)

The Lower Keys marsh rabbit (Sylvilagus palustris hefneri, LKMR), 1 of 3 subspecies of Sylvilagus palustris, is endemic to the Lower Florida Keys. The LKMR is listed as an endangered species due to predation by feral and free roaming domestic cats (Felis catus) and raccoons (Procyon lotor), road mortality, effects of storm surges, sea level rise, the small declining metapopulation size, and possible habitat loss from hardwood encroachment. The purpose of this study was to determine the current LKMR density on lands managed by the United States Navy, Naval Air Station Key West and evaluate how vegetation structure and patch elevation effect LKMR population density. I conducted fecal pellet counts to determine LKMR density, collected vegetation data using percent composition of ground cover, Robel range pole, and point-centered quarter methods, and obtained data on patch area and elevation. I used simple linear regression to assess the relationship between LKMR density and 9 measured vegetation characteristics, patch area, and patch elevation to determine which variables have an influence on LKMR density and the relationship between them. In my examination of the simple regression models, 6 out of the 11 variables appeared to influence LKMR population density. The average per patch percent composition of nonliving material and grasses, maximum height of vegetation at the range pole, distance to nearest woody vegetation, patch elevation, and visual obstruction readings (VOR) individually accounted for 26.4%, 30.4% , 18.1%, 8.5%, 6.8%, and 1.4% of the variability in LKMR density, respectively. According to the regression models, LKMR density increased in patches with greater amounts of grasses and with greater distance to woody vegetation. Habitat management is vital to the recovery of the LKMR and needs to focus on providing greater amounts of grasses and reducing the amount of woody vegetation encroachment to enhance LKMR population density.

Dedrickson, Angela

2011-12-01T23:59:59.000Z

84

High density electronic circuit and process for making  

DOE Patents (OSTI)

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.

Morgan, W.P.

1999-06-29T23:59:59.000Z

85

Oxides having high energy densities  

DOE Patents (OSTI)

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.

Ceder, Gerbrand; Kang, Kisuk

2013-09-10T23:59:59.000Z

86

Risk Bounds for Mixture Density Estimation  

E-Print Network (OSTI)

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 ...

Rakhlin, Alexander

2004-01-27T23:59:59.000Z

87

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

Science Conference Proceedings (OSTI)

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.

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

1997-09-01T23:59:59.000Z

88

Bivariate density estimation using BV regularisation  

Science Conference Proceedings (OSTI)

The problem of bivariate density estimation is studied with the aim of finding the density function with the smallest number of local extreme values which is adequate with the given data. Adequacy is defined via Kuiper metrics. The concept of the taut-string ... Keywords: Density estimation, Modality, Regularisation

Andreas Obereder; Otmar Scherzer; Arne Kovac

2007-08-01T23:59:59.000Z

89

Impact of CIR Storms on Thermosphere Density Variability during the Solar Minimum of 2008  

E-Print Network (OSTI)

The solar minimum of 2008 was exceptionally quiet, with sunspot numbers at their lowest in 75 years. During this unique solar minimum epoch, however, solar wind high - speed streams emanating from near-equatorial coronal holes occurred frequently and were the primary contributor to the recurrent geomagnetic activity at Earth. These conditions enabled the isolation of forcing by geomagnetic activity on the preconditioned solar minimum state of the upper atmosphere caused by Corotating Interaction Regions (CIRs). Thermosphere density observations around 400 km from the CHAMP satellite are used to study the thermosphere density response to solar wind high - speed streams/CIRs. Superposed epoch results show that thermosphere density responds to high - speed streams globally, and the density at 400 km changes by 75% on average. The relative changes of neutral density are comparable at different latitudes, although its variability is largest at high latitudes. In addition, the response of thermosphere density to hi...

Lei, Jiuhou; Wang, Wenbin; McPherron, Robert L

2010-01-01T23:59:59.000Z

90

Double Modelling of the Dynamic of Activities in Rural Municipalities  

E-Print Network (OSTI)

Land use choices and activity prevalence in a selected territory are determined by individual preferences constrained by the characteristic of the analysed zone: population density, soil properties, urbanization level and other similar factors can drive individuals to make different kind of decisions about their occupations. Different approaches can be used to describe land use change, occupation prevalence and their reciprocal inter-relation. In this paper we describe two different kinds of approaches: an agent based model, centred on individual choices and an aggregated model describing the evolution of activity prevalence in terms of coupled differential equation. We use and we compare the two models to analyse the effect of territorial constraints, like the lack of employment in determined sectors, on the possible activity prevalence scenarios.

Ternes, S; Huet, S; Deffuant, G

2009-01-01T23:59:59.000Z

91

TEMPORAL VARIATIONS OF FRACTURE DIRECTIONS AND FRACTURE DENSITIES IN THE  

Open Energy Info (EERE)

TEMPORAL VARIATIONS OF FRACTURE DIRECTIONS AND FRACTURE DENSITIES IN THE TEMPORAL VARIATIONS OF FRACTURE DIRECTIONS AND FRACTURE DENSITIES IN THE COSO GEOTHERMAL FIELD FROM ANALYSES OF SHEAR-WAVE SPLITTING Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Conference Proceedings: TEMPORAL VARIATIONS OF FRACTURE DIRECTIONS AND FRACTURE DENSITIES IN THE COSO GEOTHERMAL FIELD FROM ANALYSES OF SHEAR-WAVE SPLITTING Details Activities (1) Areas (1) Regions (0) Abstract: This project aims to improve understanding of the subsurface fracture system in the Coso geothermal field, located in the east central California. We applied shear-wave splitting technique on a set of high quality, locally recorded microearthquake (MEQ) data. Four major fracture directions have been identified from the seismograms recorded by the permanent sixteen-station down-hole array: N10- 20W, NS, N20E, and N40-45E,

92

Density Log at Valles Caldera - Redondo Area (Wilt & Haar, 1986) | Open  

Open Energy Info (EERE)

Valles Caldera - Redondo Area (Wilt & Haar, 1986) Valles Caldera - Redondo Area (Wilt & Haar, 1986) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Density at Valles Caldera - Redondo Area (Wilt & Haar, 1986) Exploration Activity Details Location Valles Caldera - Redondo Area Exploration Technique Density Log Activity Date Usefulness not indicated DOE-funding Unknown Notes The density log indicates three major density units within the well section : a surface layer of caldera fill, lake deposits, and other recent alluvium (2.12 g/cm3); the Bandelier Tuff and underlying volcanic and sedimentary units (2.3--2.5 g/cm3); and the basement unit, consisting of the lower Paleozoic and the upper Precambrian (2.65 g/cm3). There are, of course, significant density variations within each unit, but for modeling

93

Optimal control of population transfer in Markovian open quantum systems  

E-Print Network (OSTI)

There has long been interest to control the transfer of population between specified quantum states. Recent work has optimized the control law for closed system population transfer by using a gradient ascent pulse engineer- ing algorithm [1]. Here, a spin-boson model consisting of two-level atoms which interact with the dissipative environment, is investigated. With opti- mal control, the quantum system can invert the populations of the quantum logic states. The temperature plays an important role in controlling popula- tion transfer. At low temperatures the control has active performance, while at high temperatures it has less erect. We also analyze the decoherence be- havior of open quantum systems with optimal population transfer control, and we find that these controls can prolong the coherence time. We hope that active optimal control can help quantum solid-state-based engineering.

Wei Cui; Zairong Xi; Yu Pan

2010-04-24T23:59:59.000Z

94

Optimal control of population transfer in Markovian open quantum systems  

E-Print Network (OSTI)

There has long been interest to control the transfer of population between specified quantum states. Recent work has optimized the control law for closed system population transfer by using a gradient ascent pulse engineer- ing algorithm [1]. Here, a spin-boson model consisting of two-level atoms which interact with the dissipative environment, is investigated. With opti- mal control, the quantum system can invert the populations of the quantum logic states. The temperature plays an important role in controlling popula- tion transfer. At low temperatures the control has active performance, while at high temperatures it has less erect. We also analyze the decoherence be- havior of open quantum systems with optimal population transfer control, and we find that these controls can prolong the coherence time. We hope that active optimal control can help quantum solid-state-based engineering.

Cuia, Wei; Pan, Yu

2010-01-01T23:59:59.000Z

95

Oxygen Reduction Reaction on Dispersed and Core-Shell Metal Alloy Catalysts: Density Functional Theory Studies  

E-Print Network (OSTI)

Pt-based alloy surfaces are used to catalyze the electrochemical oxygen reduction reaction (ORR), where molecular oxygen is converted into water on fuel cell electrodes. In this work, we address challenges due to the cost of high Pt loadings in the cathode electrocatalyst, as well as those arising from catalyst durability. We aim to develop an increased understanding of the factors that determine ORR activity together with stability against surface segregation and dissolution of Pt-based alloys. We firstly focus on the problem of determining surface atomic distribution resulting from surface segregation phenomena. We use first-principles density functional theory (DFT) calculations on PtCo and Pt3Co overall compositions, as well as adsorption of water and atomic oxygen on PtCo(111) and Pt-skin structures. The bonding between water and surfaces of PtCo and Pt-skin monolayers are investigated in terms of orbital population. Also, on both surfaces, the surface reconstruction effect due to high oxygen coverage and water co-adsorption is investigated. Although the PtCo structures show good activity, a large dissolution of Co atoms tends to occur in acid medium. To tackle this problem, we examine core-shell structures which showed improved stability and activity compared to Pt(111), in particular, one consisting of a surface Pt-skin monolayer over an IrCo or Ir3Co core, with or without a Pd interlayer between the Pt surface and the Ir-Co core. DFT analysis of surface segregation, surface stability against dissolution, surface Pourbaix diagrams, and reaction mechanisms provide useful predictions on catalyst durability, onset potential for water oxidation, surface atomic distribution, coverage of oxygenated species, and activity. The roles of the Pd interlayer in the core-shell structures that influence higher ORR activity are clarified. Furthermore, the stability and activity enhancement of new shell-anchor-core structures of Pt/Fe-C/core, Pt/Co-C/core and Pt/Ni-C/core are demonstrated with core materials of Ir, Pd3Co, Ir3Co, IrCo and IrNi. Based on the analysis, Pt/Fe-C/Ir, Pt/Co-C/Ir, Pt/Ni-C/Ir, Pt/Co-C/Pd3Co, Pt/Fe-C/Pd3Co, Pt/Co- C/Ir3Co, Pt/Fe-C/Ir3Co, Pt/Co-C/IrCo, Pt/Co-C/IrNi, and Pt/Fe-C/IrNi structures show promise in terms of both improved durability and relatively high ORR activity.

Hirunsit, Pussana

2010-08-01T23:59:59.000Z

96

High Density Fuel Development for Research Reactors  

SciTech Connect

An international effort to develop, qualify, and license high and very high density fuels has been underway for several years within the framework of multi-national RERTR programs. The current development status is the result of significant contributions from many laboratories, specifically CNEA in Argentina, AECL in Canada, CEA in France, TUM in Germany, KAERI in Korea, VNIIM, RDIPE, IPPE, NCCP and RIARR in Russia, INL, ANL and Y-12 in USA. These programs are mainly engaged with UMo dispersion fuels with densities from 6 to 8 gU/cm3 (high density fuel) and UMo monolithic fuel with density as high as 16 gU/cm3 (very high density fuel). This paper, mainly focused on the French & US programs, gives the status of high density UMo fuel development and perspectives on their qualification.

Daniel Wachs; Dennis Keiser; Mitchell Meyer; Douglas Burkes; Curtis Clark; Glenn Moore; Jan-Fong Jue; Totju Totev; Gerard Hofman; Tom Wiencek; Yeon So Kim; Jim Snelgrove

2007-09-01T23:59:59.000Z

97

The Quantum Energy Density: Improved E  

Science Conference Proceedings (OSTI)

We establish a physically meaningful representation of a quantum energy density for use in Quantum Monte Carlo calculations. The energy density operator, dened in terms of Hamiltonian components and density operators, returns the correct Hamiltonian when integrated over a volume containing a cluster of particles. This property is demonstrated for a helium-neon \\gas," showing that atomic energies obtained from the energy density correspond to eigenvalues of isolated systems. The formation energies of defects or interfaces are typically calculated as total energy dierences. Using a model of delta-doped silicon (where dopant atoms form a thin plane) we show how interfacial energies can be calculated more eciently with the energy density, since the region of interest is small. We also demonstrate how the energy density correctly transitions to the bulk limit away from the interface where the correct energy is obtainable from a separate total energy calculation.

Krogel, Jaron [University of Illinois, Urbana-Champaign; Yu, Min [Lawrence Berkeley National Laboratory (LBNL); Kim, Jeongnim [ORNL; Ceperley, David M. [University of Illinois, Urbana-Champaign

2013-01-01T23:59:59.000Z

98

Applying the multivariate time-rescaling theorem to neural population models  

E-Print Network (OSTI)

Statistical models of neural activity are integral to modern neuroscience. Recently interest has grown in modeling the spiking activity of populations of simultaneously recorded neurons to study the effects of correlations ...

Gerhard, Felipe

99

Considering Air Density in Wind Power Production  

E-Print Network (OSTI)

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.

Zénó Farkas

2011-03-11T23:59:59.000Z

100

Dynamic Evolution for Risk-Neutral Densities  

E-Print Network (OSTI)

We solved the scaled formulation for problems (7) and (10) and obtained the dynamic evolution for the densities (see Figure 1). For this data set, we.

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101

Some challenges for Nuclear Density Functional Theory  

E-Print Network (OSTI)

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.

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

2006-06-20T23:59:59.000Z

102

Application of Precession Electron Diffraction in Density ...  

Science Conference Proceedings (OSTI)

In this paper, GND density calculations obtained using SEM-based EBSD and transmission electron microscope-based PED techniques in ?+? titanium alloys ...

103

MECHANICALLY ROBUST, ELECTRICALLY CONDUCTIVE ULTRALOW-DENSITY ...  

A method of making a mechanically robust, electrically conductive ultralow-density carbon nanotube-based aerogel, including the steps of dispersing nanotubes in an ...

104

Betatron radiation from density tailored plasmas  

E-Print Network (OSTI)

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

Ta Phuoc, Kim

2010-01-01T23:59:59.000Z

105

3-D capacitance density imaging system  

DOE Patents (OSTI)

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.

Fasching, G.E.

1988-03-18T23:59:59.000Z

106

High Energy Density Secondary Lithium Batteries  

High Energy Density Secondary Lithium Batteries Note: The technology described above is an early stage opportunity. Licensing rights to this intellectual property may

107

A Model for the Origin of High Density in Loop-top X-ray Sources  

E-Print Network (OSTI)

Super-hot looptop sources, detected in some large solar flares, are compact sources of HXR emission with spectra matching thermal electron populations exceeding 30 megakelvins. High observed emission measure, as well as inference of electron thermalization within the small source region, both provide evidence of high densities at the looptop; typically more than an order of magnitude above ambient. Where some investigators have suggested such density enhancement results from a rapid enhancement in the magnetic field strength, we propose an alternative model, based on Petschek reconnection, whereby looptop plasma is heated and compressed by slow magnetosonic shocks generated self-consistently through flux retraction following reconnection. Under steady conditions such shocks can enhance density by no more than a factor of four. These steady shock relations (Rankine-Hugoniot relations) turn out to be inapplicable to Petschek's model owing to transient effects of thermal conduction. The actual density enhancemen...

Longcope, D W

2011-01-01T23:59:59.000Z

108

Energy Systems and Population Health  

Science Conference Proceedings (OSTI)

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.

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

109

Estimate of dielectric density using spectroscopic ellipsometry  

Science Conference Proceedings (OSTI)

The optical dielectric functions for hafnium oxide and hafnium silicate films were extracted from spectroscopic ellipsometry measurements and the density then calculated using a previously proposed method. The values obtained were then compared to those ... Keywords: Density, Gadolinium oxide, Hafnium silicate, Medium energy ion scattering, Spectroscopic ellipsometry, X-ray reflectometry

W. Davey; O. Buiu; M. Werner; I. Z. Mitrovic; S. Hall; P. Chalker

2009-07-01T23:59:59.000Z

110

High density laser-driven target  

DOE Patents (OSTI)

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.

Lindl, John D. (San Ramon, CA)

1981-01-01T23:59:59.000Z

111

Laser light absorption with density profile modifications  

SciTech Connect

Two-dimensional computer simulations studied plasma heating by electron plasma waves. The results emphasize the importance of nonlinear steepening of the density profile near the critical density. A typical simulation result is presented in order to illustrate these profile modifications. It is shown that large dc magnetic field generation is an inherent property of the absorption of obliquely-incident light. (MOW)

Kruer, W.; Valeo, E.; Estabrook, K.; Langdon, B.; Lasinski, B.

1974-12-01T23:59:59.000Z

112

Density of Spray-Formed Materials  

SciTech Connect

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.

Kevin M. McHugh; Volker Uhlenwinkel; Nils Ellendr

2008-06-01T23:59:59.000Z

113

Density Log at Alum Area (Moos & Ronne, 2010) | Open Energy Information  

Open Energy Info (EERE)

Moos & Ronne, 2010) Moos & Ronne, 2010) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Density Log at Alum Geothermal Area (Moos & Ronne, 2010) Exploration Activity Details Location Alum Geothermal Area Exploration Technique Density Log Activity Date Usefulness useful DOE-funding Unknown Notes Density, photo-electric factor (PEF), neutron, and gamma ray (GR) logs provided sufficient information to clearly delineate basement lithologic variations, suggesting that pulsed neutron logs may not in many cases be needed, and density and electrical resistivity data were important to calibrate structural models based on surface surveys. References Daniel Moos, Joel Ronne (2010) Selecting The Optimal Logging Suite For Geothermal Reservoir Evaluation- Results From The Alum 25-29 Well,

114

Instabilities in the Nuclear Energy Density Functional  

E-Print Network (OSTI)

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.

M. Kortelainen; T. Lesinski

2010-02-05T23:59:59.000Z

115

Low density, resorcinol-formaldehyde aerogels  

DOE Patents (OSTI)

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.

Pekala, R.W.

1989-10-10T23:59:59.000Z

116

Low density, resorcinol-formaldehyde aerogels  

DOE Patents (OSTI)

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 {le}100 mg/cc; cell size {le}0.1 microns). The aerogels are transparent, dark red in color and consist of interconnected colloidal-like particles with diameters of about 100 A{degrees}. These aerogels may be further carbonized to form low density carbon foams with cell size of about 0.1 micron. 1 ref., 1 tab.

Pekala, R.W.

1989-09-12T23:59:59.000Z

117

Low density, resorcinol-formaldehyde aerogels  

DOE Patents (OSTI)

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.

Pekala, Richard W. (Pleasant Hill, CA)

1989-01-01T23:59:59.000Z

118

Low density, resorcinol-formaldehyde aerogels  

DOE Patents (OSTI)

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.

Pekala, Richard W. (Pleasant Hill, CA)

1991-01-01T23:59:59.000Z

119

Phase Diagram of Amorphous Solid Water: Low-Density, High-Density, and Very-High-Density Amorphous Ices  

E-Print Network (OSTI)

We describe the phase diagram of amorphous solid water by performing molecular dynamics simulations. Our simulations follow different paths in the phase diagram: isothermal compression/decompression, isochoric cooling/heating and isobaric cooling/heating. We are able to identify low-density amorphous (LDA), high-density amorphous (HDA), and very-high density amorphous (VHDA) ices. The density $\\rho$ of these glasses at different pressure $P$ and temperature $T$ agree well with experimental values. We also study the radial distribution functions of glassy water. We obtain VHDA by isobaric heating of HDA, as in experiment. We also find that ``other forms'' of glassy water can be obtained upon isobaric heating of LDA, as well as amorphous ices formed during the transformation of LDA to HDA. We argue that these other forms of amorphous ices, as well as VHDA, are not altogether new glasses but rather are the result of aging induced by heating. Samples of HDA and VHDA with different densities are recovered at normal $P$, showing that there is a continuum of glasses. Furthermore, the two ranges of densities of recovered HDA and recovered VHDA overlap at ambient $P$. Our simulations are consistent with the possibility of HDA$\\to$LDA and VHDA$\\to$LDA transformations, reproducing the experimental findings. We do not observe a VHDA$\\to$HDA transformation.

Nicolas Giovambattista; H. Eugene Stanley; Francesco Sciortino

2005-02-22T23:59:59.000Z

120

wave power density | OpenEI  

Open Energy Info (EERE)

power density power density Dataset Summary Description This project estimates the naturally available and technically recoverable U.S. wave energy resources, using a 51-month Wavewatch III hindcast database developed especially for this study by National Oceanographic and Atmospheric Administration's (NOAA's) National Centers for Environmental Prediction. For total resource estimation, wave power density in terms of kilowatts per meter is aggregated across a unit diameter circle. Source Electric Power Research Institute (EPRI) Date Released December 05th, 2011 (2 years ago) Date Updated Unknown Keywords EPRI MHK NREL ocean Virginia Tech wave wave power density Data application/pdf icon Download Full Report (pdf, 8.8 MiB) Quality Metrics Level of Review Some Review Comment

Note: This page contains sample records for the topic "activity population density" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


121

Velocity Probability Density Functions for Oceanic Floats  

Science Conference Proceedings (OSTI)

Probability density functions (PDFs) of daily velocities from subsurface floats deployed in the North Atlantic and equatorial Atlantic Oceans are examined. In general, the PDFs are approximately Gaussian for small velocities, but with significant ...

Annalisa Bracco; J. H. LaCasce; Antonello Provenzale

2000-03-01T23:59:59.000Z

122

Definition: Rock Density | Open Energy Information  

Open Energy Info (EERE)

in crustal rocks. Rock density is a physical characteristic that is governed by the chemical composition (in situ minerals) and pore spaces of a specific rock or rock type.1...

123

High density load bearing insulation peg  

DOE Patents (OSTI)

A high density peg is disclosed which can support a large load and exhibits excellent thermal resistance produced by a method wherein the peg is made in compliance with specified conditions of time, temperature and pressure. 4 figs.

Nowobilski, J.J.; Owens, W.J.

1985-01-29T23:59:59.000Z

124

Density controlled carbon nanotube array electrodes  

DOE Patents (OSTI)

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.

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

2008-12-16T23:59:59.000Z

125

High density load bearing insulation peg  

DOE Patents (OSTI)

A high density peg which can support a large load and exhibits excellent thermal resistance produced by a method wherein the peg is made in compliance with specified conditions of time, temperature and pressure.

Nowobilski, Jeffert J. (Orchard Park, NY); Owens, William J. (Kenmore, NY)

1985-01-01T23:59:59.000Z

126

Velocity Probability Density Functions from Altimetry  

Science Conference Proceedings (OSTI)

Probability density functions (pdfs) are employed to evaluate the distribution of velocities in the global ocean. This study computes pdfs of ocean surface velocity using altimetric data from the TOPEX/Poseidon satellite. Results show that the ...

Sarah T. Gille; Stefan G. Llewellyn Smith

2000-01-01T23:59:59.000Z

127

Density equalizing map projections (cartograms) in public health applications  

Science Conference Proceedings (OSTI)

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.

Merrill, D.W.

1998-05-01T23:59:59.000Z

128

A Comprehensive Study Of Fracture Patterns And Densities In The Geysers  

Open Energy Info (EERE)

Study Of Fracture Patterns And Densities In The Geysers Study Of Fracture Patterns And Densities In The Geysers Geothermal Reservoir Using Microearthquake Shear-Wave Splitting Tomography Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Report: A Comprehensive Study Of Fracture Patterns And Densities In The Geysers Geothermal Reservoir Using Microearthquake Shear-Wave Splitting Tomography Details Activities (1) Areas (1) Regions (0) Abstract: In this project we developed a method for using seismic S-wave data to map the patterns and densities of sub-surface fractures in the NW Geysers Geothermal Field/ (1) This project adds to both the general methods needed to characterize the geothermal production fractures that supply steam for power generation and to the specific knowledge of these in the Geysers area. (2)By locating zones of high fracture density it will be

129

NEUTRONIC REACTOR HAVING LOCALIZED AREAS OF HIGH THERMAL NEUTRON DENSITIES  

DOE Patents (OSTI)

A nuclear reactor for the irradiation of materials designed to provide a localized area of high thermal neutron flux density in which the materials to be irradiated are inserted is described. The active portion of the reactor is comprised of a cubicle graphite moderator of about 25 feet in length along each axis which has a plurality of cylindrical channels for accommodatirg elongated tubular-shaped fuel elements. The fuel elements have radial fins for spacing the fuel elements from the channel walls, thereby providing spaces through which a coolant may be passed, and also to serve as a heatconductirg means. Ducts for accommnodating the sample material to be irradiated extend through the moderator material perpendicular to and between parallel rows of fuel channels. The improvement is in the provision of additional fuel element channels spaced midway between 2 rows of the regular fuel channels in the localized area surrounding the duct where the high thermal neutron flux density is desired. The fuel elements normally disposed in the channels directly adjacent the duct are placed in the additional channels, and the channels directly adjacent the duct are plugged with moderator material. This design provides localized areas of high thermal neutron flux density without the necessity of providing additional fuel material.

Newson, H.W.

1958-06-01T23:59:59.000Z

130

Density logging and density of rocks in Rainier Mesa Area, Nevada Test Site  

SciTech Connect

Density logs from all 35 vertical drill holes in the Rainier Mesa area in which logs were obtained were evaluated and the distribution of densities of units in the geologic section was derived. Densities were obtained in only 10 holes in which calibrated logging tools had been run. The logs from an additional 10 holes were calibrated with core. Densities vary from nearly 1 g/cc in tunnel bed 5 to over 2.8 g/cc in the dolomitic rocks. Log densities were found to agree well with core data in those subunits (chiefly within tunnel beds 3 and 4) where an adequate number of core measurements were available for comparison. Lithologic correlations based on density log signatures were found to extend for more than 8 km in several units and subunits in the area. Although the volcanic rocks in the Rainier Mesa area are comprised of a wider spectrum of minerals than the petroliferous rocks generally involved in most commercial logging applications, grain density may be estimated with good accuracy with only a knowledge of glass and zeolite content. The variability of the Z/A ratio of the matrix in these volcanic rocks is also negligible compared to the value of 0.5 generally assumed in density logging. However, due to the assumptions made concerning the Z/A of water in deriving the output of commercial density tools, one should be aware of the errors inherent in assuming that recorded log densities are true densities. These errors are normally small, being less than 3 percent for compensated limestone'' tools and 2 percent for tools which output electron density. 35 refs., 25 figs., 12 tabs.

Carroll, R.D.

1989-01-01T23:59:59.000Z

131

Precise and Accurate Density Determination of Explosives Using Hydrostatic Weighing  

SciTech Connect

Precise and accurate density determination requires weight measurements in air and water using sufficiently precise analytical balances, knowledge of the densities of air and water, knowledge of thermal expansions, availability of a density standard, and a method to estimate the time to achieve thermal equilibrium with water. Density distributions in pressed explosives are inferred from the densities of elements from a central slice.

B. Olinger

2005-07-01T23:59:59.000Z

132

High-Energy-Density Plasmas, Fluids  

NLE Websites -- All DOE Office Websites (Extended Search)

High-Energy-Density Plasmas, Fluids High-Energy-Density Plasmas, Fluids /science-innovation/_assets/images/icon-science.jpg High-Energy-Density Plasmas, Fluids National security depends on science and technology. The United States relies on Los Alamos National Laboratory for the best of both. No place on Earth pursues a broader array of world-class scientific endeavors. TRIDENT target chamber Sasi Palaniyappan, right, and Rahul Shah left inside a target chamber where the TRIDENT short pulse laser is aimed at a very thin diamond- foil target, a fraction of a micrometer thick. The laser delivers a power on target of 150 Terawatts focused into a 7 micrometer spot, yielding laser brilliance over 100 times more intense than needed to make the target electrons fully relativistic. These experiments test novel methods of producing intense

133

Low density, resorcinol-formaldehyde aerogels  

DOE Patents (OSTI)

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.

Pekala, R.W.

1988-05-26T23:59:59.000Z

134

Fabrication of low density ceramic material  

DOE Patents (OSTI)

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.

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

1985-01-01T23:59:59.000Z

135

CENTER FOR PULSED POWER DRIVEN HIGH ENERGY DENSITY PLASMA STUDIES  

SciTech Connect

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.

Professor Bruce R. Kusse; Professor David A. Hammer

2007-04-18T23:59:59.000Z

136

Low density, microcellular foams, preparation, and articles  

DOE Patents (OSTI)

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.

Young, A.T.

1982-03-03T23:59:59.000Z

137

Thermal Density Functional Theory in Context  

E-Print Network (OSTI)

This chapter introduces thermal density functional theory, starting from the ground-state theory and assuming a background in quantum mechanics and statistical mechanics. We review the foundations of density functional theory (DFT) by illustrating some of its key reformulations. The basics of DFT for thermal ensembles are explained in this context, as are tools useful for analysis and development of approximations. We close by discussing some key ideas relating thermal DFT and the ground state. This review emphasizes thermal DFT's strengths as a consistent and general framework.

Pribram-Jones, Aurora; Gross, E K U; Burke, Kieron

2013-01-01T23:59:59.000Z

138

Dark Energy Density in Brane World  

E-Print Network (OSTI)

We present a possible explanation to the tiny positive cosmological constant under the frame of AdS$_5$ spacetime embedded by a dS$_4$ brane. We calculate the dark energy density by summing the zero point energy of massive scalar fields in AdS$_5$ spacetime. Under the assumption that the radius of AdS$_5$ spacetime is of the same magnitude as the radius of observable universe, the dark energy density in dS$_4$ brane is obtained, which is smaller than the observational value. The reasons are also discussed.

Hai-Bao Wen; Xin-Bing Huang

2005-02-08T23:59:59.000Z

139

Dworshak Reservoir Kokanee Population Monitoring, Annual Report 2001.  

DOE Green Energy (OSTI)

Onsite testing of strobe lights was conducted to determine if they repelled kokanee Oncorhynchus nerka away from the turbine intakes at Dworshak Dam. We tested a set of nine strobe lights flashing at a rate of 360 flashes/min placed near the intake of a 90 mW turbine. A split-beam echo sounder was used to determine the effect of strobe light operation on fish density (thought to be mostly kokanee) in front of the turbine intakes. On five nights between December 2001 and January 2002, fish density averaged 110 fish/ha when no lights were flashing. Mean density dropped to 13 fish/ha when the strobe lights were turned on during five additional nights of sampling. This 88% decline in density was significant at the P = 0.009 level of significance based on a paired Student's t test. There appeared to be no tendency for fish to habituate to the lights during the night. Test results indicate that a single set of nine lights may be sufficient to repel kokanee from a turbine intake during the night. We also used split-beam hydroacoustics to monitor the kokanee population in Dworshak Reservoir during 2001. Estimated abundance of kokanee has continued to increase since the spring of 1996 when high entrainment losses occurred. Based on hydroacoustic surveys, we estimated 3,276,000 kokanee in Dworshak Reservoir in early July 2001. This included 2,069,000 age-0 kokanee (90% CI {+-} 16.4%), 801,000 age-1 kokanee (90% CI {+-} 17.8%), and 406,000 age-2 kokanee (90% CI {+-} 20.5%). Entrainment sampling was also conducted with split-beam hydroacoustics a minimum of one continuous 24 h period per month. The highest entrainment rates occurred at night with lower discharges and shallower intake depths. Fish movement patterns suggested that they swam 'at will' in front of the intakes and may have chosen to move into the turbine intakes. Based on monthly hydroacoustic sampling in the forebay, we found that kokanee density was low in July and August during a period of high discharge. However, kokanee density was high in late winter when discharge was also high, thus increasing the likelihood of entrainment. Counts of spawning kokanee in four tributary streams used as an index reached 6,079 fish. This spawner count appeared unusually low considering the high population estimate of kokanee in the reservoir and data collected in previous years.

Maiolie, Melo; Stark, Eric

2003-03-01T23:59:59.000Z

140

Population Dynamics of Aedes aegypti and Dengue as Influenced by Weather and Human Behavior in San Juan, Puerto Rico  

E-Print Network (OSTI)

Previous studies on the influence of weather on Aedes aegypti dynamics in Puerto Rico suggested that rainfall was a significant driver of immature mosquito populations and dengue incidence, but mostly in the drier areas of the island. We conducted a longitudinal study of Ae. aegypti in two neighborhoods of the metropolitan area of San Juan city, Puerto Rico where rainfall is more uniformly distributed throughout the year. We assessed the impacts of rainfall, temperature, and human activities on the temporal dynamics of adult Ae. aegypti and oviposition. Changes in adult mosquitoes were monitored with BG-Sentinel traps and oviposition activity with CDC enhanced ovitraps. Pupal surveys were conducted during the drier and wetter parts of the year in both neighborhoods to determine the contribution of humans and rains to mosquito production. Mosquito dynamics in each neighborhood was compared with dengue incidence in their respective municipalities during the study. Our results showed that: 1. Most pupae were produced in containers managed by people, which explains the prevalence of adult mosquitoes at times when rainfall was scant; 2. Water meters were documented for the first time as productive habitats for Ae. aegypti; 3. Even though Puerto Rico has a reliable supply of tap water and an active tire recycling program, water storage containers and discarded tires were important mosquito producers; 4. Peaks in mosquito density preceded maximum dengue incidence; and 5. Ae. aegypti dynamics were driven by weather and human

Roberto Barrera; Manuel Amador; Andrew J. Mackay

2011-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "activity population density" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


141

Relation between the High Density Phase and the Very-High Density Phase of Amorphous Solid Water  

E-Print Network (OSTI)

Relation between the High Density Phase and the Very-High Density Phase of Amorphous Solid Water; published 18 March 2005) It has been suggested that high-density amorphous (HDA) ice is a structurally arrested form of high- density liquid (HDL) water, while low-density amorphous ice is a structurally

Sciortino, Francesco

142

Density Functional Theory Approach to Nuclear Fission  

E-Print Network (OSTI)

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.

N. Schunck

2012-12-13T23:59:59.000Z

143

Nonlinear spectral density estimation: thresholding the correlogram  

E-Print Network (OSTI)

in a nonlinear way. The rate of convergence of the new estimators is quantified, and practical issues estimation of the spectral density function; examples include astronomy, economics, electrical engineering Einstein (1914); see Brillinger (1993) for a historical perspective. The prevalent spectral estimation

Politis, Dimitris N.

144

Density estimation for spatial data streams  

Science Conference Proceedings (OSTI)

In this paper we study the problem of estimating several types of spatial queries in a streaming environment. We propose a new approach, which we call Local Kernels, for computing density estimators by using local rather than global statistics on the ...

Cecilia M. Procopiuc; Octavian Procopiuc

2005-08-01T23:59:59.000Z

145

Lattice QCD and High Baryon Density State  

SciTech Connect

We report our recent studies on the finite density QCD obtained from lattice QCD simulation with clover-improved Wilson fermions of two flavor and RG-improved gauge action. We approach the subject from two paths, i.e., the imaginary and chemical potentials.

Nagata, Keitaro [Department of Physics, University of Tokyo, Bunkyo-ku, Tokyo 113-0033 (Japan); Research Institute for Information Science and Education, Hiroshima University, Higashi-Hiroshima 739-8527 (Japan); Nakamura, Atsushi; Motoki, Shinji [Research Institute for Information Science and Education, Hiroshima University, Higashi-Hiroshima 739-8527 (Japan); Nakagawa, Yoshiyuki [Graduate School of Science and Technology, Niigata University, Niigata 950-2181 (Japan); Saito, Takuya [Integrated Information Center, Kochi University, Kochi, 780-8520 (Japan)

2011-10-21T23:59:59.000Z

146

Interferometer for the measurement of plasma density  

SciTech Connect

An interferometer which combines the advantages of a coupled cavity interferometer requiring alignment of only one light beam, and a quadrature interferometer which has the ability to track multi-fringe phase excursions unambiguously. The device utilizes a Bragg cell for generating a signal which is electronically analyzed to unambiguously determine phase modulation which is proportional to the path integral of the plasma density.

Jacobson, Abram R. (Los Alamos, NM)

1980-01-01T23:59:59.000Z

147

Bayesian Generalized Probability Calculus for Density Matrices  

E-Print Network (OSTI)

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 can be seen as a special case when the density matrix is restricted to be diagonal. We develop a probability calculus based on these more general distributions that includes definitions of joints, conditionals and formulas that relate these, including analogs of the Theorem of Total Probability and various Bayes rules for the calculation of posterior density matrices. The resulting calculus parallels the familiar "conventional" probability calculus and always retains the latter as a special case when all matrices are diagonal. We motivate both the conventional and the generalized Bayes rule with a minimum relative entropy principle, where the Kullbach-Leibler version gives the conventional Bayes rule and Umegaki's quantum relative entropy the new Bayes rule for density matrices. Whereas the conventional Bayesian methods maintain uncertainty about which model has the highest data likelihood, the generalization maintains uncertainty about which unit direction has the largest variance. Surprisingly the bounds also generalize: as in the conventional setting we upper bound the negative log likelihood of the data by the negative log likelihood of the MAP estimator.

Manfred K Warmuth; Dima Kuzmin

2009-01-09T23:59:59.000Z

148

Vibrated Bulk Density (VBD) of Calcined Petroleum Coke and ...  

Science Conference Proceedings (OSTI)

Abstract Scope, Vibrated bulk density (VBD) is a quantitative measurement used in the aluminum industry to evaluate the density of calcined petroleum coke.

149

An Optimization of Electrode Energy and Power Density through...  

NLE Websites -- All DOE Office Websites (Extended Search)

An Optimization of Electrode Energy and Power Density through of Variations in Inactive Material and Electrode Porosity Title An Optimization of Electrode Energy and Power Density...

150

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

National Nuclear Security Administration (NNSA)

NNSA Archive Federal Employment Apply for Our Jobs Our Jobs Working at NNSA Blog High Energy Density Laboratory Plasmas Program Home > High Energy Density Laboratory Plasmas...

151

Density Forecasting for Long-Term Peak Electricity Demand  

E-Print Network (OSTI)

Long-term electricity demand forecasting plays an important role in planning for future generation facilities and transmission augmentation. In a long-term context, planners must adopt a probabilistic view of potential peak demand levels. Therefore density forecasts (providing estimates of the full probability distributions of the possible future values of the demand) are more helpful than point forecasts, and are necessary for utilities to evaluate and hedge the financial risk accrued by demand variability and forecasting uncertainty. This paper proposes a new methodology to forecast the density of long-term peak electricity demand. Peak electricity demand in a given season is subject to a range of uncertainties, including underlying population growth, changing technology, economic conditions, prevailing weather conditions (and the timing of those conditions), as well as the general randomness inherent in individual usage. It is also subject to some known calendar effects due to the time of day, day of week, time of year, and public holidays. A comprehensive forecasting solution is described in this paper. First, semi-parametric additive models are used to estimate the relationships between demand and the driver variables, including temperatures, calendar effects and some demographic and economic variables. Then the demand distributions are forecasted by using a mixture of temperature simulation, assumed future economic scenarios, and residual bootstrapping. The temperature simulation is implemented through a new seasonal bootstrapping method with variable blocks. The proposed methodology has been used to forecast the probability distribution of annual and weekly peak electricity demand for South Australia since 2007. The performance of the methodology is evaluated by comparing the forecast results with the actual demand of the summer 2007–2008.

Rob J. Hyndman; Shu Fan

2009-01-01T23:59:59.000Z

152

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

DOE Green Energy (OSTI)

My 2.5-yr Master'Â?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.

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

2012-08-31T23:59:59.000Z

153

Density dependence and the economic efficacy of marine reserves  

E-Print Network (OSTI)

et al (2008a) Northeast arctic cod population persistence inet al (2008b) Northeast arctic cod population persistence inpotential in Atlantic cod Gadus morhua. Mar Ecol Prog Ser

White, Crow

2009-01-01T23:59:59.000Z

154

Effective pairing interactions with isospin density dependence  

Science Conference Proceedings (OSTI)

We perform Hartree-Fock-Bogoliubov (HFB) calculations for semi-magic calcium, nickel, tin, and lead isotopes and N=20,28,50, and 82 isotones using density-dependent pairing interactions recently derived from a microscopic nucleon-nucleon interaction. These interactions have an isovector component so that the pairing gaps in symmetric and neutron matter are reproduced. Our calculations well account for the experimental data for the neutron number dependence of binding energy, two-neutron separation energy, and odd-even mass staggering of these isotopes. This result suggests that by introducing the isovector term in the pairing interaction, one can construct a global effective pairing interaction that is applicable to nuclei in a wide range of the nuclear chart. It is also shown with the local density approximation that the pairing field deduced from the pairing gaps in infinite matter reproduces qualitatively well the pairing field for finite nuclei obtained with the HFB method.

Margueron, J. [Institut de Physique Nucleaire, IN2P3-CNRS and Universite Paris-Sud, F-91406 Orsay Cedex (France); Center for Mathematical Sciences, University of Aizu, Aizu-Wakamatsu, 965-8580 Fukushima (Japan); Sagawa, H. [Center for Mathematical Sciences, University of Aizu, Aizu-Wakamatsu, 965-8580 Fukushima (Japan); Hagino, K. [Department of Physics, Tohoku University, Sendai, 980-8578 (Japan)

2008-05-15T23:59:59.000Z

155

Kinetics driving high-density chlorine plasmas  

Science Conference Proceedings (OSTI)

A simple fluid model was developed in order to investigate the driving kinetics of neutral and charged species in high-density chlorine plasmas. It was found that the dissociation degree of Cl{sub 2} molecules is directly linked to the power balance of the discharge which controls the electron density. The model was also used to identify those reactions that could be neglected in the particle balance of charged species and those that must be included. Our results further indicate that diffusion losses need to be considered up to a pressure that depends on magnetic-field intensity and reactor aspect ratio. Finally, it is shown that the dominant charged carriers are linked to the dissociation level of Cl{sub 2} molecules.

Stafford, L.; Margot, J.; Vidal, F.; Chaker, M.; Giroux, K.; Poirier, J.-S.; Quintal-Leonard, A.; Saussac, J. [Department de physique, Universite de Montreal, Montreal, Quebec (Canada); INRS-Energie, Materiaux et Telecommunications, Varennes, Quebec (Canada); Department de physique, Universite de Montreal, Montreal, Quebec (Canada)

2005-09-15T23:59:59.000Z

156

Turbulent Density Spectrum in Solar Wind Plasma  

E-Print Network (OSTI)

The density fluctuation spectrum in the solar wind reveals a Kolmogorov-like scaling with a spectral slope of -5/3 in wavenumber space. The energy transfer process in the magnetized solar wind, characterized typically by MHD turbulence, over extended length-scales remains an unresolved paradox of modern turbulence theories, raising the question of how a compressible magnetofluid exhibits a turbulent spectrum that is characteristic of an incompressible hydrodynamic fluid. To address these questions, we have undertaken three-dimensional time dependent numerical simulations of a compressible magnetohydrodynamic fluid describing super-Alfv\\'enic, supersonic and strongly magnetized plasma fluid. It is shown that a Kolmogorov-like density spectrum can develop by plasma motions that are dominated by Alfv\\'enic cascades whereas compressive modes are dissipated.

Shaikh, Dastgeer

2009-01-01T23:59:59.000Z

157

Density Spectrum in the Solar Wind Plasma  

E-Print Network (OSTI)

The density fluctuation spectrum in the solar wind reveals a Kolmogorov-like scaling with a spectral slope of -5/3 in wavenumber space. The energy transfer process in the magnetized solar wind, characterized typically by MHD turbulence, over extended length-scales remains an unresolved paradox of modern turbulence theories, raising the question of how a compressible magnetofluid exhibits a turbulent spectrum that is characteristic of an incompressible hydrodynamic fluid. To address these questions, we have undertaken three-dimensional time dependent numerical simulations of a compressible magnetohydrodynamic fluid describing super-Alfv\\'enic, supersonic and strongly magnetized plasma fluid. It is shown that a Kolmogorov-like density spectrum can develop by plasma motions that are dominated by Alfv\\'enic cascades whereas compressive modes are dissipated.

Shaikh, Dastgeer

2009-01-01T23:59:59.000Z

158

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

SciTech Connect

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.

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

2009-07-15T23:59:59.000Z

159

Mapping densities in a noisy state space  

E-Print Network (OSTI)

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.

Domenico Lippolis

2013-03-05T23:59:59.000Z

160

Nuclear fission in covariant density functional theory  

E-Print Network (OSTI)

The current status of the application of covariant density functional theory to microscopic description of nuclear fission with main emphasis on superheavy nuclei (SHN) is reviewed. The softness of SHN in the triaxial plane leads to an emergence of several competing fission pathes in the region of the inner fission barrier in some of these nuclei. The outer fission barriers of SHN are considerably affected both by triaxiality and octupole deformation.

A. V. Afanasjev; H. Abusara; P. Ring

2013-09-12T23:59:59.000Z

Note: This page contains sample records for the topic "activity population density" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


161

Energy trapping from Hagedorn densities of states  

E-Print Network (OSTI)

In this note, we construct simple stochastic toy models for holographic gauge theories in which distributions of energy on a collection of sites evolve by a master equation with some specified transition rates. We build in only energy conservation, locality, and the standard thermodynamic requirement that all states with a given energy are equally likely in equilibrium. In these models, we investigate the qualitative behavior of the dynamics of the energy distributions for different choices of the density of states for the individual sites. For typical field theory densities of states (\\log(\\rho(E)) ~ E^{\\alphaenergy spread out relatively quickly. For large N gauge theories with gravitational duals, the density of states for a finite volume of field theory degrees of freedom typically includes a Hagedorn regime (\\log(\\rho(E)) ~ E). We find that this gives rise to a trapping of energy in subsets of degrees of freedom for parametrically long time scales before the energy leaks away. We speculate that this Hagedorn trapping may be part of a holographic explanation for long-lived gravitational bound states (black holes) in gravitational theories.

Connor Behan; Klaus Larjo; Nima Lashkari; Brian Swingle; Mark Van Raamsdonk

2013-04-26T23:59:59.000Z

162

ON THE LOCAL DARK MATTER DENSITY  

SciTech Connect

An analysis of the kinematics of 412 stars at 1-4 kpc from the Galactic midplane by Moni Bidin et al. has claimed to derive a local density of dark matter that is an order of magnitude below standard expectations. We show that this result is incorrect and that it arises from the assumption that the mean azimuthal velocity of the stellar tracers is independent of Galactocentric radius at all heights. We substitute the assumption, supported by data, that the circular speed is independent of radius in the midplane. We demonstrate that the assumption of constant mean azimuthal velocity is implausible by showing that it requires the circular velocity to drop more steeply than allowed by any plausible mass model, with or without dark matter, at large heights above the midplane. Using the approximation that the circular-velocity curve is flat in the midplane, we find that the data imply a local dark matter density of 0.008 {+-} 0.003 M{sub Sun} pc{sup -3} = 0.3 {+-} 0.1 GeV cm{sup -3}, fully consistent with standard estimates of this quantity. This is the most robust direct measurement of the local dark matter density to date.

Bovy, Jo; Tremaine, Scott [Institute for Advanced Study, Einstein Drive, Princeton, NJ 08540 (United States)

2012-09-01T23:59:59.000Z

163

The string of variable density: Further results  

Science Conference Proceedings (OSTI)

We analyze the problem of calculating the solutions and the spectrum of a string with arbitrary density and fixed ends. We build a perturbative scheme which uses a basis of WKB-type functions and obtain explicit expressions for the eigenvalues and eigenfunctions of the string. Using this approach we show that it is possible to derive the asymptotic (high energy) behavior of the string, obtaining explicit expressions for the first three coefficients (the first two can also be obtained with the WKB method). Finally, using an iterative approach we also obtain analytical expressions for the low energy behavior of the eigenvalues and eigenfunctions of a string with rapidly oscillating density, recovering (in a simpler way) results in the literature. - Highlights: > We devise a perturbative approach to finding the modes of a string with arbitrary density. > We obtain explicitly the first three coefficients of the asymptotic high energy expansion. > We apply our findings to a series of examples, obtaining both analytical and numerical results.

Amore, Paolo, E-mail: paolo.amore@gmail.com

2011-09-15T23:59:59.000Z

164

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

Science Conference Proceedings (OSTI)

Broad Funding Opportunity Announcement Project: FastCAP is improving the performance of an ultracapacitor—a 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 density—high energy density means more energy storage. FastCAP is redesigning the ultracapacitor’s internal structure to increase its energy density. Ultracapacitors traditionally use electrodes made of irregularly shaped, porous carbon. FastCAP’s ultracapacitors are made of tiny, aligned carbon nanotubes. The nanotubes provide a regular path for ions moving in and out of the ultracapacitor’s electrode, increasing the overall efficiency and energy density of the device.

None

2010-04-01T23:59:59.000Z

165

PROCESS FOR IMPROVING THE ENERGY DENSITY OF FEEDSTOCKS USING ...  

PROCESS FOR IMPROVING THE ENERGY DENSITY OF FEEDSTOCKS USING FORMATE SALTS United States Patent Application

166

On the density of a graph and its blowup  

Science Conference Proceedings (OSTI)

It is well known that, of all graphs with edge-density p, the random graph G(n,p) contains the smallest density of copies of K"t","t, the complete bipartite graph of size 2t. Since K"t","t is a t-blowup of an edge, the following intriguing open question ... Keywords: Blowup, Graph density, Triangle density

Asaf Shapira; Raphael Yuster

2010-11-01T23:59:59.000Z

167

MAGNETIC FLUX DENSITY MEASURED IN FAST AND SLOW SOLAR WIND STREAMS  

Science Conference Proceedings (OSTI)

The radial component of the heliospheric magnetic field vector is used to estimate the open magnetic flux density of the Sun. This parameter has been calculated using observations from the Ulysses mission that covered heliolatitudes from 80 Degree-Sign S to 80 Degree-Sign N, from 1990 to 2009 and distances from 1 to 5.4 AU, the Advanced Composition Explorer mission at 1 AU from 1997 to 2010, the OMNI interplanetary database from 1971, and the Helios 1 and 2 missions that covered the distance range from 0.3 to 1 AU. The flux density was found to be much affected by fluctuations in the magnetic field which make its calculated value dependent on heliospheric location, type of solar wind (fast or slow), and the level of solar activity. However, fluctuations are distributed symmetrically perpendicular to the average Parker direction. Therefore, distributions of the field vector in the two-dimensional plane defined by the radial and azimuthal directions in heliospheric coordinates provide a way to reduce the effects of the fluctuations on the measurement of the flux density. This leads to a better defined flux density parameter; the distributions modified by removing the effects of fluctuations then allow a clearer assessment of the dependence of the flux density on heliospheric location, solar wind type, and solar activity. This assessment indicates that the flux density normalized to 1 AU is independent of location and solar wind type (fast or slow). However, there is a residual dependence on solar activity which can be studied using the modified flux density measurements.

Erdos, G. [Wigner Research Centre for Physics of the Hungarian Academy of Sciences, H-1525 Budapest, POB 49 (Hungary); Balogh, A., E-mail: erdos.geza@wigner.mta.hu [The Blackett Laboratory, Imperial College, London SW7 2BZ (United Kingdom)

2012-07-10T23:59:59.000Z

168

Design and Qualification of High-Density Polyethylene for ASME Safety Class 3 Piping Systems  

Science Conference Proceedings (OSTI)

This report identifies the activities necessary and recommends a plan to gather needed data to establish design and qualification methods that will serve as the basis for ASME and regulatory approvals for allowing the nuclear power industry to use high-density polyethylene for Safety Class 3 applications.

2005-12-23T23:59:59.000Z

169

Observations of High Ground Flash Densities of Positive Lightning in Summertime Thunderstorms  

Science Conference Proceedings (OSTI)

Observations of summertime thunderstorms indicate that positive polarity cloud-to-ground lightning activity can occur with rates as high as 67 flashes in 5 min and spatial densities up to 0.60 flashes per square kilometer per hour. All ground ...

Maribeth Stolzenburg

1994-08-01T23:59:59.000Z

170

Population enumeration and the effects of oil and gas development on dune-dwelling lizards  

E-Print Network (OSTI)

Habitat loss is one of the leading causes of species decline across all taxa and conservation practices require information on population trends. The Mescalero Sands ecosystem, New Mexico, USA, is experiencing landscape changes associated with oil and gas development. The dune-dwelling lizard community contains a habitat specialist, Sceloporus arenicolus, that is of particular interest because it has a very limited geographic distribution that is entirely subject to oil and gas development. Distance sampling is widely used to estimate population densities of many vertebrate taxa however assumptions can be difficult to satisfy with certain species or in certain habitats. Researchers must investigate the likelihood that assumptions can be satisfied before implementing any population sampling method. I had two objectives. First to investigate the precision of population densities of dune-dwelling lizards estimated via distance sampling that was coupled with double-observer surveys. Second to compare abundances of dune-dwelling lizards among sites that varied in oil and gas development. I conducted distance line transects and compared those density estimates to densities obtained from total removal plots. I quantified the amount of oil and gas development, habitat quantity and quality and correlated those to lizard abundances to investigate the effects of oil and gas development on lizard populations. I found large differences in density estimates from distance sampling and total removal plots that resulted from violation of distance sampling assumptions. Although distance sampling is a low cost method, it does not produce reliable density estimates for dune-dwelling lizards and is not an appropriate sampling method in this system. I did not find oil and gas development effects on the habitat quantity, quality or on the abundances of lizards. Lizard abundances were most strongly correlated to habitat quantity. Lizard abundances may be influenced by complex interactions between oil and gas development and habitat quantity and quality but controlling for those interactions was beyond the scope of my study. Before and after experiments and long-term studies at multiple sites would be required to more fully address the effects of oil and gas development on lizard populations in the Mescalero Sands.

Smolensky, Nicole Limunga

2008-05-01T23:59:59.000Z

171

Symmetry energy in nuclear density functional theory  

E-Print Network (OSTI)

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.

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

2013-07-22T23:59:59.000Z

172

Symmetry energy in nuclear density functional theory  

E-Print Network (OSTI)

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.

Nazarewicz, W; Satula, W; Vretenar, D

2013-01-01T23:59:59.000Z

173

A study of fast electron energy transport in relativistically intense laser-plasma interactions with large density scalelengths  

SciTech Connect

A systematic experimental and computational investigation of the effects of three well characterized density scalelengths on fast electron energy transport in ultra-intense laser-solid interactions has been performed. Experimental evidence is presented which shows that, when the density scalelength is sufficiently large, the fast electron beam entering the solid-density plasma is best described by two distinct populations: those accelerated within the coronal plasma (the fast electron pre-beam) and those accelerated near or at the critical density surface (the fast electron main-beam). The former has considerably lower divergence and higher temperature than that of the main-beam with a half-angle of {approx}20 Degree-Sign . It contains up to 30% of the total fast electron energy absorbed into the target. The number, kinetic energy, and total energy of the fast electrons in the pre-beam are increased by an increase in density scalelength. With larger density scalelengths, the fast electrons heat a smaller cross sectional area of the target, causing the thinnest targets to reach significantly higher rear surface temperatures. Modelling indicates that the enhanced fast electron pre-beam associated with the large density scalelength interaction generates a magnetic field within the target of sufficient magnitude to partially collimate the subsequent, more divergent, fast electron main-beam.

Scott, R. H. H.; Norreys, P. A. [Department of Physics, Blackett Laboratory, Imperial College London, Prince Consort Road, London, SW7 2AZ (United Kingdom); Central Laser Facility, STFC Rutherford Appleton Laboratory, Harwell Oxford, Didcot, Oxford OX11 0QX (United Kingdom); Perez, F.; Baton, S. D. [LULI, Ecole Polytechnique, UMR 7605, CNRS/CEA/UPMC, Route de Saclay, 91128 Palaiseau (France); Santos, J. J.; Nicolai, Ph.; Hulin, S. [Univ. Bordeaux/CNRS/CEA, CELIA, UMR 5107, 33405 Talence (France); Ridgers, C. P. [Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU (United Kingdom); Department of Physics, Blackett Laboratory, Imperial College London, Prince Consort Road, London, SW7 2AZ (United Kingdom); Davies, J. R. [GoLP, Instituto de Plasmas e Fusao Nuclear - Laboratorio Associado, Instituto Superior Tecnico, 1049-001 Lisboa (Portugal); Lancaster, K. L.; Trines, R. M. G. M. [Central Laser Facility, STFC Rutherford Appleton Laboratory, Harwell Oxford, Didcot, Oxford OX11 0QX (United Kingdom); Bell, A. R.; Tzoufras, M. [Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU (United Kingdom); Central Laser Facility, STFC Rutherford Appleton Laboratory, Harwell Oxford, Didcot, Oxford OX11 0QX (United Kingdom); Rose, S. J. [Department of Physics, Blackett Laboratory, Imperial College London, Prince Consort Road, London, SW7 2AZ (United Kingdom)

2012-05-15T23:59:59.000Z

174

Supernova rates and stellar populations  

E-Print Network (OSTI)

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.

F. Mannucci

2007-08-03T23:59:59.000Z

175

Vibration-Induced Conductivity Fluctuation Measurement for Soil Bulk Density Analysis  

E-Print Network (OSTI)

Soil bulk density affects water storage, water and nutrient movement, and plant root activity in the soil profile. Its measurement is difficult in field conditions. Vibration-induced conductivity fluctuation was investigated to quantify soil bulk density with possible field applications in the future. The AC electrical conductivity of soil was measured using a pair of blade-like electrodes while exposing the soil to periodic vibration. The blades were positioned longitudinally and transversally to the direction of the induced vibration to enable the calculation of a normalized index. The normalized index was expected to provide data independent from the vibration strength and to reduce the effect of soil salinity and water content. The experiment was conducted on natural and salinized fine sand at two moisture conditions and four bulk densities. The blade-shaped electrodes improved electrode-soil contact compared to cylindrical electrodes, and thereby, reduced measurement noise. Simulations on a simplified resistor lattice indicate that the transversal effect increases as soil bulk density decreases. Measurement of dry sand showed a negative correlation between the normalized conductivity fluctuation and soil bulk density for both longitudinal and transversal settings. The decrease in the transversal signal was smaller than expected. The wet natural and salinized soils performed very similarly as hypothesized, but their normalized VICOF response was not significant to bulk density changes.

Andrea Sz. Kishne; Cristine L. S. Morgan; Hung-Chih Chang; Laszlo B. Kish

2007-05-03T23:59:59.000Z

176

Computing 1-D atomic densities in macromolecular simulations: the Density Profile Tool for VMD  

E-Print Network (OSTI)

Molecular dynamics simulations have a prominent role in biophysics and drug discovery due to the atomistic information they provide on the structure, energetics and dynamics of biomolecules. Specialized software packages are required to analyze simulated trajectories, either interactively or via scripts, to derive quantities of interest and provide insight for further experiments. This paper presents the Density Profile Tool, a package that enhances the Visual Molecular Dynamics environment with the ability to interactively compute and visualize 1-D projections of various density functions of molecular models. We describe how the plugin is used to perform computations both via a graphical interface and programmatically. Results are presented for realistic examples, all-atom bilayer models, showing how mass and electron densities readily provide measurements such as membrane thickness, location of structural elements, and how they compare to X-ray diffraction experiments.

Giorgino, Toni

2013-01-01T23:59:59.000Z

177

Nuclear Star Clusters - Structure and Stellar Populations  

E-Print Network (OSTI)

This is an overview of nuclear star cluster observations, covering their structure, stellar populations, kinematics and possible connection to black holes at the centers of galaxies.

Neumayer, Nadine

2012-01-01T23:59:59.000Z

178

Four Most Populous States - Energy Information Administration  

U.S. Energy Information Administration (EIA)

RESIDENTIAL ENERGY CONSUMPTION SURVEY 1997. OVERVIEW: MOST POPULOUS STATES ... Homes with air-conditioning: 62%... with a central air-conditioning system: 18%

179

Optimal control of leukemic cell population dynamics  

E-Print Network (OSTI)

Sep 5, 2013 ... This issue can be formulated as an optimal control problem. The dynamics of leukemic cell populations in culture is given by age-structured ...

180

Ohmically heated high-density Z pinch  

SciTech Connect

The gross properties of a high-density (n approximately equal to 10$sup 27$ m$sup -3$), small-radius, (r = 10$sup -4$ m) gas-imbedded Z pinch have been examined considering only classical processes. The rate equation using only ohmic heating along with bremsstrahlung and radial heat transport shows that ohmic heating will rapidly take the pinch to thermonuclear temperatures for currents, I, greater than 1 MA. The radial heat loss for the pinch is very small for I greater than 1.5 MA. This suggests that the pinch could tolerate being driven to a nearby wall by an m = 1 kink. The laser technology for initiation of the small-diameter filament and the high-voltage technology for giving a 30-ns rise to a MA or more are available now. Some reactor considerations have been included. (auth)

Hammel, J.E.

1976-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "activity population density" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


181

Competition between superconductivity and spin density wave  

E-Print Network (OSTI)

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.

Tian De Cao

2011-01-02T23:59:59.000Z

182

Vacuum Outgassing of High Density Polyethylene  

Science Conference Proceedings (OSTI)

A combination of thermogravimetric analysis (TGA) and temperature programmed decomposition (TPD) was employed to identify the outgassing species, the total amount of outgassing, and the outgassing kinetics of high density polyethylene (HDPE) in a vacuum environment. The isoconversional kinetic analysis was then used to analyze the outgassing kinetics and to predict the long-term outgassing of HDPE in vacuum applications at ambient temperature. H{sub 2}O and C{sub n}H{sub x} with n as high as 9 and x centering around 2n are the major outgassing species from solid HDPE, but the quantities evolved can be significantly reduced by vacuum baking at 368 K for a few hours prior to device assembly.

Dinh, L N; Sze, J; Schildbach, M A; Chinn, S C; Maxwell, R S; Raboin, P; McLean II, W

2008-08-11T23:59:59.000Z

183

BRST technique for the cosmological density matrix  

E-Print Network (OSTI)

The microcanonical density matrix in closed cosmology has a natural definition as a projector on the space of solutions of Wheeler-DeWitt equations, which is motivated by the absence of global non-vanishing charges and energy in spatially closed gravitational systems. Using the BRST/BFV formalism in relativistic phase space of gauge and ghost variables we derive the path integral representation for this projector and the relevant statistical sum. This derivation circumvents the difficulties associated with the open algebra of noncommutative quantum Dirac constraints and the construction/regularization of the physical inner product in the subspace of BRS singlets. This inner product is achieved via the Batalin-Marnelius gauge fixing in the space of BRS-invariant states, which in its turn is shown to be a result of truncation of the BRST/BFV formalism to the "matter" sector of relativistic phase space.

Andrei O. Barvinsky

2013-08-14T23:59:59.000Z

184

Orthobaric Density: A Thermodynamic Variable for Ocean Circulation Studies  

Science Conference Proceedings (OSTI)

A new density variable, empirically corrected for pressure, is constructed. This is done by first fitting compressibility (or sound speed) computed from global ocean datasets to an empirical function of pressure and in situ density (or specific ...

Roland A. de Szoeke; Scott R. Springer; David M. Oxilia

2000-11-01T23:59:59.000Z

185

High power density supercapacitors using locally aligned carbon nanotube electrodes  

E-Print Network (OSTI)

B E 1999 Electrochemical Supercapacitor ( New York: Kluwer–power density of a supercapacitor is its most remarkablepower density of a supercapacitor is given by P max = V i

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

2005-01-01T23:59:59.000Z

186

Constrained Density-Functional Theory--Configuration Interaction  

E-Print Network (OSTI)

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 ...

Kaduk, Benjamin James

2012-01-01T23:59:59.000Z

187

Innovative fuel designs for high power density pressurized water reactor  

E-Print Network (OSTI)

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 ...

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

2006-01-01T23:59:59.000Z

188

Design of annular fuel for high power density BWRs  

E-Print Network (OSTI)

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 ...

Morra, Paolo

2005-01-01T23:59:59.000Z

189

Density of Freshly Fallen Snow in the Central Rocky Mountains  

Science Conference Proceedings (OSTI)

New snow density distributions are presented for six measurement sites in the mountains of Colorado and Wyoming. Densities were computed from daily measurements of new snow depth and water equivalent from snow board cores. All data were measured ...

Arthur Judson; Nolan Doesken

2000-07-01T23:59:59.000Z

190

Controlling Defect Density in Polymer-Fullerene Bulk Heterojunction ...  

Science Conference Proceedings (OSTI)

Controlling Defect Density in Polymer-Fullerene Bulk Heterojunction Solar Cells by Optimizing ... Engineering Carbon Nanomaterials for Energy Application.

191

Density without Disruption [EDRA / Places Awards, 2004 -- Awards Commentary  

E-Print Network (OSTI)

Density without Disruption Awards Commentary country today,CCS Architecture for a planning award. Such work stands as a

Gratz, Roberta Brandes

2004-01-01T23:59:59.000Z

192

Inexpensive Production of High Density Thin Ceramic Films ...  

For Industry; For Researchers; Success Stories; About Us; Available Technologies. Browse By Category Advanced Materials; ... density of the ceramic ...

193

Fatigue Weak-Link Density and Strength Distribution in High ...  

Science Conference Proceedings (OSTI)

Symposium, Fatigue and Corrosion Damage in Metallic Materials: Fundamentals, Modeling and Prevention. Presentation Title, Fatigue Weak-Link Density and ...

194

Improving Baked Anode Density and Air Permeability Through ...  

Science Conference Proceedings (OSTI)

Presentation Title, Improving Baked Anode Density and Air Permeability Through Process Optimization and Coke Blending. Author(s), Bienvenu Ndjom, ...

195

Density-Enthalpy Phase Diagram 0D Boiler Simulation  

E-Print Network (OSTI)

Density-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;Density-Enthalpy Phase Diagram 0D Boiler Simulation Finite Element Method Further Research Goal

Vuik, Kees

196

Quantum coherent switch utilizing commensurate nanoelectrode and charge density periodicities  

DOE Patents (OSTI)

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.

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

2008-08-05T23:59:59.000Z

197

A digital rock density map of New Zealand  

Science Conference Proceedings (OSTI)

Digital geological maps of New Zealand (QMAP) are combined with 9256 samples with rock density measurements from the national rock catalogue PETLAB and supplementary geological sources to generate a first digital density model of New Zealand. This digital ... Keywords: Crust, Database, Density, Geological mapping, Gravimetry, Rock types

Robert Tenzer; Pascal Sirguey; Mark Rattenbury; Julia Nicolson

2011-08-01T23:59:59.000Z

198

High fidelity field simulations using density and pressure based approaches  

Science Conference Proceedings (OSTI)

Density-based and pressure-based approaches in solving the Navier-Stokes equations for computational field simulations for compressible and incompressible flows have been presented. For the density-based flow solver, a generalized grid based framework ... Keywords: CFD, Density-based method, Pressure-based method

Gary C. Cheng; Roy P. Koomullil; Bharat K. Soni

2005-11-01T23:59:59.000Z

199

Study of atomic physics and population inversions with plasma focus  

SciTech Connect

The plasma focus can be used to generate high temperature and high density plasmas. Neon-like plasmas have previously been studied in Z-pinches and laser produced plasmas as sources for XUV and x-ray lasers. The plasma focus provides a simple and inexpensive source for studying atomic physics of highly ionized atoms. A detailed understanding of atomic physics at high temperatures, densities, and megagauss magnetic fields is necessary for possible x-ray laser designs. Methods that are generally used for obtaining population inversions include collisional ionization of the inner shells of multi-electron atoms and ions, photoexcitation, and electron collisional excitation of ions, collisional combination of ions, and atom-ion resonant charge exchange. We will discuss some possible experiments to help understand the atomic physics under the above condition. Some ideas and calculations will be given to show the feasibility of doing atomic physics relating to x-ray lasers with a plasma focus. 13 refs., 2 figs.

Oona, H.; Hodgdon, M.L.; Rickel, D.G.; Freeman, B.L.

1989-01-01T23:59:59.000Z

200

Vibration-Induced Conductivity Fluctuation Measurement for Soil Bulk Density Analysis  

E-Print Network (OSTI)

Soil bulk density affects water storage, water and nutrient movement, and plant root activity in the soil profile. Its measurement is difficult in field conditions. Vibration-induced conductivity fluctuation was investigated to quantify soil bulk density with possible field applications in the future. The AC electrical conductivity of soil was measured using a pair of blade-like electrodes while exposing the soil to periodic vibration. The blades were positioned longitudinally and transversally to the direction of the induced vibration to enable the calculation of a normalized index. The normalized index was expected to provide data independent from the vibration strength and to reduce the effect of soil salinity and water content. The experiment was conducted on natural and salinized fine sand at two moisture conditions and four bulk densities. The blade-shaped electrodes improved electrode-soil contact compared to cylindrical electrodes, and thereby, reduced measurement noise. Simulations on a simplified re...

Kishne, Andrea Sz; Chang, Hung-Chih; Kish, Laszlo B

2007-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "activity population density" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


201

Long-term variation of fiddler crab populations in North Carolina salt marshes  

SciTech Connect

As part of the environmental monitoring of possible effects of the Brunswick nuclear power plant fiddle crab populations were sampled in several salt marshes in the lower Cape Fear River estuary, North Carolina for five years. Total biomass of the fiddler crabs Uca Pugnax and U. minax in four Spartina marshes declined by 65 to 70% between the summers of 1974-1975 and 1976-1977 with no significant decrease in population density; there was evidence of a recovery in summer of 1978 to the 1974-1975 levels. The cause of these fluctuations is unknown, but such a degree of variability in intertidal populations emphasizes the need for caution in using one or two-year baseline studies to evalute potential environmental impacts. 1 figure, 2 table.

Cammen, L.M.; Seneca, E.D.; Stroud, L.M.

1984-06-01T23:59:59.000Z

202

wind power density | OpenEI  

Open Energy Info (EERE)

density density Dataset Summary Description This dataset was developed by the National Renewable Energy Laboratory (NREL) for the U.S. Source National Renewable Energy Lab (NREL) Date Released Unknown Date Updated Unknown Keywords afghanistan dataset GIS Wind Power wind power density Data application/zip icon Wind Power Density at 50-m Above Ground Level GIS Data (zip, 1.4 MiB) Quality Metrics Level of Review Some Review Comment Temporal and Spatial Coverage Frequency Time Period License License Other or unspecified, see optional comment below Comment DISCLAIMER NOTICE This GIS data was developed by the National Renewable Energy Laboratory ("NREL"), which is operated by the Alliance for Sustainable Energy, LLC for the U.S. Department of Energy ("DOE"). The user is granted the right, without any fee or cost, to use, copy, modify, alter, enhance and distribute this data for any purpose whatsoever, provided that this entire notice appears in all copies of the data. Further, the user of this data agrees to credit NREL in any publications or software that incorporate or use the data. Access to and use of the GIS data shall further impose the following obligations on the User. The names DOE/NREL may not be used in any advertising or publicity to endorse or promote any product or commercial entity using or incorporating the GIS data unless specific written authorization is obtained from DOE/NREL. The User also understands that DOE/NREL shall not be obligated to provide updates, support, consulting, training or assistance of any kind whatsoever with regard to the use of the GIS data. THE GIS DATA IS PROVIDED "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL DOE/NREL BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER, INCLUDING BUT NOT LIMITED TO CLAIMS ASSOCIATED WITH THE LOSS OF DATA OR PROFITS, WHICH MAY RESULT FROM AN ACTION IN CONTRACT, NEGLIGENCE OR OTHER TORTIOUS CLAIM THAT ARISES OUT OF OR IN CONNECTION WITH THE ACCESS OR USE OF THE GIS DATA. The User acknowledges that access to the GIS data is subject to U.S. Export laws and regulations and any use or transfer of the GIS data must be authorized under those regulations. The User shall not use, distribute, transfer, or transmit GIS data or any products incorporating the GIS data except in compliance with U.S. export regulations. If requested by DOE/NREL, the User agrees to sign written assurances and other export-related documentation as may be required to comply with U.S. export regulations. DISCLAIMER NOTICE This GIS data was developed by the National Renewable Energy Laboratory ("NREL"), which is operated by the Alliance for Sustainable Energy, LLC for the U.S. Department of Energy ("DOE"). The user is granted the right, without any fee or cost, to use, copy, modify, alter, enhance and distribute this data for any purpose whatsoever, provided that this entire notice appears in all copies of the data. Further, the user of this data agrees to credit NREL in any publications or software that incorporate or use the data. Access to and use of the GIS data shall further impose the following obligations on the User. The names DOE/NREL may not be used in any advertising or publicity to endorse or promote any product or commercial entity using or incorporating the GIS data unless specific written authorization is obtained from DOE/NREL. The User also understands that DOE/NREL shall not be obligated to provide updates, support, consulting, training or assistance of any kind whatsoever with regard to the use of the GIS data. THE GIS DATA IS PROVIDED "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL DOE/NREL BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER, INCLUDING BUT NOT LIMITED TO CLAIMS ASSOCIATED WITH THE LOSS OF DATA OR PROFITS, WHICH MAY RESULT FROM AN ACTION IN CONTRACT, NEGLIGENCE OR OTHER TORTIOUS CLAIM THAT ARISES OUT OF OR IN CONNECTION WITH THE ACCESS OR USE OF THE GIS DATA. The User acknowledges that access to the GIS data is subject to U.S. Export laws and regulations and any use or transfer of the GIS data must be authorized under those regulations. The User shall not use, distribute, transfer, or transmit GIS data or any products incorporating the GIS data except in compliance with U.S. export regulations. If requested by DOE/NREL, the User agrees to sign written assurances and other export-related documentation as may be required to comply with U.S. export regulations.

203

Density matrix, superconductivity and molecular structure  

Science Conference Proceedings (OSTI)

Starting from Yang`s offdiagonal long-range order concept and the macroscopic occupation condition for the second order density matrix as the basis for condensation phenomena the authors develop the notion that the extremal wave function (EWF), which is related to these conditions, leads to superconductivity in monatomic systems. It is proven that the BCS model and the version where it is projected onto a fixed number of particles possesses EWF properties, differs negligibly from the EWF, and conserves offdiagonal long-range order. The condition for the EWF to be energetically favored is the presence of macroscopic degenerate one-electron energy levels in the system, partial occupation of this degenerate region, and also an effective attraction among the electrons. Considerations are advanced indicating that these conditions are satisfied in the high temperature superconducting metal oxide ceramics, due to the presence of macroscopically degenerate diffusion orbitals distributed among the O{sup -} ions in the CuO{sub 2} layers, and with the effective screening of these layers by the metal-like La, Ba, Y, or O layers. 51 refs., 3 figs., 1 tab.

Mestechkin, M.M.; Klimko, G.T.; Vaiman, G.E. [Academy of Science of the Ukrainian SSR, Donetsk (Russian Federation)

1992-01-01T23:59:59.000Z

204

Flat Central Density Profile and Constant DM Surface Density in Galaxies from Scalar Field Dark Matter  

E-Print Network (OSTI)

The scalar field dark matter (SFDM) model proposes that galaxies form by condensation of a scalar field (SF) very early in the universe forming Bose-Einstein Condensates (BEC) drops, i.e., in this model haloes of galaxies are gigantic drops of SF. Here big structures form like in the LCDM model, by hierarchy, thus all the predictions of the LCDM model at big scales are reproduced by SFDM. This model predicts that all galaxies must be very similar and exist for bigger redshifts than in the LCDM model. In this work we show that BEC dark matter haloes fit high-resolution rotation curves of a sample of thirteen low surface brightness galaxies. We compare our fits to those obtained using a Navarro-Frenk-White and Pseudo-Isothermal (PI) profiles and found a better agreement with the SFDM and PI profiles. The mean value of the logarithmic inner density slopes is -0.27 +/- 0.18. As a second result we find a natural way to define the core radius with the advantage of being model-independent. Using this new definition in the BEC density profile we find that the recent observation of the constant dark matter central surface density can be reproduced. We conclude that in light of the difficulties that the standard model is currently facing the SFDM model can be a worthy alternative to keep exploring further.

Victor H. Robles; Tonatiuh Matos

2012-01-14T23:59:59.000Z

205

Activation detector  

DOE Patents (OSTI)

A method of detecting an activator, the method including impinging with an activator a receptor material lacking a photoluminescent material and generating a by-product of a radioactive decay due to the activator impinging the receptor material. The method further including, generating light from the by-product via the Cherenkov effect and identifying a characteristic of the activator based on the light.

Bell, Zane William (Oak Ridge, TN); Boatner, Lynn Allen (Oak Ridge, TN)

2009-12-08T23:59:59.000Z

206

Hanford Site Regional Population - 2010 Census  

Science Conference Proceedings (OSTI)

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.

Hamilton, Erin L.; Snyder, Sandra F.

2011-08-12T23:59:59.000Z

207

Disaggregating measurement uncertainty from population variability and Bayesian treatment of uncensored results  

Science Conference Proceedings (OSTI)

In making low-level radioactivity measurements of populations, it is commonly observed that a substantial portion of net results are negative. Furthermore, the observed variance of the measurement results arises from a combination of measurement uncertainty and population variability. This paper presents a method for disaggregating measurement uncertainty from population variability to produce a probability density function (PDF) of possibly true results. To do this, simple, justifiable, and reasonable assumptions are made about the relationship of the measurements to the measurands (the 'true values'). The measurements are assumed to be unbiased, that is, that their average value is the average of the measurands. Using traditional estimates of each measurement's uncertainty to disaggregate population variability from measurement uncertainty, a PDF of measurands for the population is produced. Then, using Bayes's theorem, the same assumptions, and all the data from the population of individuals, a prior PDF is computed for each individual's measurand. These PDFs are non-negative, and their average is equal to the average of the measurement results for the population. The uncertainty in these Bayesian posterior PDFs is all Berkson with no remaining classical component. The methods are applied to baseline bioassay data from the Hanford site. The data include 90Sr urinalysis measurements on 128 people, 137Cs in vivo measurements on 5,337 people, and 239Pu urinalysis measurements on 3,270 people. The method produces excellent results for the 90Sr and 137Cs measurements, since there are nonzero concentrations of these global fallout radionuclides in people who have not been occupationally exposed. The method does not work for the 239Pu measurements in non-occupationally exposed people because the population average is essentially zero.

Strom, Daniel J.; Joyce, Kevin E.; Maclellan, Jay A.; Watson, David J.; Lynch, Timothy P.; Antonio, Cheryl L.; Birchall, Alan; Anderson, Kevin K.; Zharov, Peter

2012-04-17T23:59:59.000Z

208

The nuclear energy density functional formalism  

E-Print Network (OSTI)

The present document focuses on the theoretical foundations of the nuclear energy density functional (EDF) method. As such, it does not aim at reviewing the status of the field, at covering all possible ramifications of the approach or at presenting recent achievements and applications. The objective is to provide a modern account of the nuclear EDF formalism that is at variance with traditional presentations that rely, at one point or another, on a {\\it Hamiltonian-based} picture. The latter is not general enough to encompass what the nuclear EDF method represents as of today. Specifically, the traditional Hamiltonian-based picture does not allow one to grasp the difficulties associated with the fact that currently available parametrizations of the energy kernel $E[g',g]$ at play in the method do not derive from a genuine Hamilton operator, would the latter be effective. The method is formulated from the outset through the most general multi-reference, i.e. beyond mean-field, implementation such that the single-reference, i.e. "mean-field", derives as a particular case. As such, a key point of the presentation provided here is to demonstrate that the multi-reference EDF method can indeed be formulated in a {\\it mathematically} meaningful fashion even if $E[g',g]$ does {\\it not} derive from a genuine Hamilton operator. In particular, the restoration of symmetries can be entirely formulated without making {\\it any} reference to a projected state, i.e. within a genuine EDF framework. However, and as is illustrated in the present document, a mathematically meaningful formulation does not guarantee that the formalism is sound from a {\\it physical} standpoint. The price at which the latter can be enforced as well in the future is eventually alluded to.

T. Duguet

2013-09-02T23:59:59.000Z

209

Method for spatially distributing a population  

DOE Patents (OSTI)

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.

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

210

HUMAN SUBJECT RESEARCH INVOLVING SPECIAL SUBJECT POPULATIONS  

E-Print Network (OSTI)

, April 18, 1979. While there are legitimate ethical concerns whenever vulnerable populations are studied of which are intended to be submitted later to, or held for inspection by, the Food and Drug Administration

Sibille, Etienne

211

Planning combat outposts to maximize population security  

E-Print Network (OSTI)

Combat outposts (COPs) are small, well-protected bases from which soldiers reside and conduct operations from. Used extensively during the "Surge" in Iraq, COPs are usually established in populated areas and are prevalent ...

Seidel, Scott B

2010-01-01T23:59:59.000Z

212

Microwave measurements of electron density in a spherical inertial- electrostatic confinement system using six ion guns  

SciTech Connect

The electron density in a spherical inertial-electrostatic confinement device using six ion beams was studied with microwave techniques involving the fundamental and higher order cavity resonances. Thermal expansion problems were circumvented by switched operation of the device. The deuterium background pressure was found to be a dominant factor in determining n/sub e/ throughout the entire range of 0.4 to 10 milliTorr. With 1 m Torr pressure and 10 mA total ion current (at 20 to 40 keV) central electron densities of the order of 10$sup 9$ electrons/ cm$sup 3$ were estimated, with total population of approximately 10$sup 10$ electrons. No evidence of shell structure of the electron density was found, although the use of higher order modes to obtain better spatial resolution was precluded by the low magnitude of n/sub e/. Indirect indication of weak ion trapping was obtained by measurement of the enhancement of neutron flux that resulted when the guns were operated simultaneously. (auth)

Chan, A.I.Y.

1975-08-01T23:59:59.000Z

213

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

Science Conference Proceedings (OSTI)

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.

GJ Schuster, FA Simonen, SR Doctor

2008-04-01T23:59:59.000Z

214

Upgrading of biorenewables to high energy density fuels  

DOE Green Energy (OSTI)

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.

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

215

Density Inhomogeneities and Electron Mobility in Supercritical Xenon  

NLE Websites -- All DOE Office Websites (Extended Search)

Density Inhomogeneities and Electron Mobility in Supercritical Xenon Density Inhomogeneities and Electron Mobility in Supercritical Xenon Richard A. Holroyd, Kengo Itoh, and Masaru Nishikawa J. Chem. Phys. 118, 706-710 (2003) [Find paper at Scitation] Abstract: The low-field mobility of electrons in supercritical Xe has been measured isothermally as a function of density above the critical temperature (289.7 K). At 293 K the mobility varies from a high of 890 cm2/Vs at 9.2 x 1021 atoms/cm3 to a minimum value of 4.6 cm2/Vs at a density of 3.5 x 1021 atoms/cm3, which is just below the critical density. The density dependence of the mobility is reasonably well predicted by the deformation potential model if the adiabatic compressibility is used to characterize the electron-medium interactions. Approximate agreement indicates that

216

The Quantum Energy Density: Improved Efficiency for Quantum Monte Carlo  

E-Print Network (OSTI)

We establish a physically meaningful representation of a quantum energy density for use in Quantum Monte Carlo calculations. The energy density operator, defined in terms of Hamiltonian components and density operators, returns the correct Hamiltonian when integrated over a volume containing a cluster of particles. This property is demonstrated for a helium-neon "gas," showing that atomic energies obtained from the energy density correspond to eigenvalues of isolated systems. The formation energies of defects or interfaces are typically calculated as total energy differences. Using a model of delta-doped silicon (where dopant atoms form a thin plane) we show how interfacial energies can be calculated more efficiently with the energy density, since the region of interest is small. We also demonstrate how the energy density correctly transitions to the bulk limit away from the interface where the correct energy is obtainable from a separate total energy calculation.

Krogel, Jaron T; Kim, Jeongnim; Ceperley, David M

2013-01-01T23:59:59.000Z

217

Nuclear symmetry energy at subnormal densities from measured nuclear masses  

E-Print Network (OSTI)

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.

Liu, Min; Li, Zhuxia; Zhang, Fengshou

2010-01-01T23:59:59.000Z

218

Nuclear symmetry energy at subnormal densities from measured nuclear masses  

E-Print Network (OSTI)

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.

Min Liu; Ning Wang; Zhuxia Li; Fengshou Zhang

2010-11-17T23:59:59.000Z

219

Method for measuring the density of lightweight materials  

DOE Patents (OSTI)

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.

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

1980-01-01T23:59:59.000Z

220

Method for solvent extraction with near-equal density solutions  

DOE Patents (OSTI)

Disclosed is a modified centrifugal contactor for separating solutions of near equal density. The modified contactor has a pressure differential establishing means that allows the application of a pressure differential across fluid in the rotor of the contactor. The pressure differential is such that it causes the boundary between solutions of near-equal density to shift, thereby facilitating separation of the phases. Also disclosed is a method of separating solutions of near-equal density.

Birdwell, Joseph F. (Knoxville, TN); Randolph, John D. (Maryville, TN); Singh, S. Paul (Oak Ridge, TN)

2001-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "activity population density" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


221

Constraints on primordial density perturbations from induced gravitational waves  

SciTech Connect

We consider the stochastic background of gravitational waves produced during the radiation-dominated hot big bang as a constraint on the primordial density perturbation on comoving length scales much smaller than those directly probed by the cosmic microwave background or large-scale structure. We place weak upper bounds on the primordial density perturbation from current data. Future detectors such as BBO and DECIGO will place much stronger constraints on the primordial density perturbation on small scales.

Assadullahi, Hooshyar; Wands, David [Institute of Cosmology and Gravitation, University of Portsmouth, Dennis Sciama Building, Burnaby Road, Portsmouth PO1 3FX (United Kingdom)

2010-01-15T23:59:59.000Z

222

United Nations Population Information Network | Open Energy Information  

Open Energy Info (EERE)

United Nations Population Information Network United Nations Population Information Network Jump to: navigation, search Tool Summary LAUNCH TOOL Name: United Nations Population Information Network Agency/Company /Organization: United Nations Focus Area: People and Policy Resource Type: Dataset Website: www.un.org/popin/ Cost: Free United Nations Population Information Network Screenshot References: United Nations Population Information Network[1] Logo: United Nations Population Information Network The Population Information Network (POPIN) strives to make international, regional and national population information, particularly information available from United Nations sources, easily available to the international community. "The Population Information Network (POPIN) was founded on 9 May 1979, by

223

Effect of Chemical Pressure on the Charge Density Wave Transition...  

NLE Websites -- All DOE Office Websites (Extended Search)

at SSRL and the department of Applied Physics at Stanford University has determined the phase diagram of a new family of prototypical charge density wave (CDW) compounds. These...

224

City of Seattle - Density Bonus for Green Buildings (Washington...  

Open Energy Info (EERE)

Edit with form History Share this page on Facebook icon Twitter icon City of Seattle - Density Bonus for Green Buildings (Washington) This is the approved revision of...

225

LINDENS: A program for lineament length and density ...  

Science Conference Proceedings (OSTI)

... or horizontal strata, lineaments are related to fractures and faults ... give an idea of the fracture pattern of ... and density analysis of recent fracturing in the ...

2013-07-15T23:59:59.000Z

226

Variational Two-electron Reduced Density Matrix Theory for Many ...  

E-Print Network (OSTI)

Sep 16, 2005 ... Abstract: The energy and properties of a many-electron atom or ... of a two- electron reduced density matrix (2-RDM) that is constrained to ...

227

The Reduced Density Matrix Method for Electronic Structure ...  

E-Print Network (OSTI)

Oct 14, 2003 ... This suggested to Mayer that the ground state energy. – and density matrix information – could be economically computed by simply carrying ...

228

Few transportation fuels surpass the energy densities of gasoline ...  

U.S. Energy Information Administration (EIA)

Natural gas, either in liquefied form (LNG) or compressed (CNG), are lighter than gasoline but again have lower densities per unit volume.

229

Few transportation fuels surpass the energy densities of ...  

U.S. Energy Information Administration (EIA)

Energy density and the cost, weight, and size of onboard energy storage are important characteristics of fuels for transportation. Fuels that require ...

230

Inexpensive Production of High Density Thin Ceramic Films on ...  

Steven Visco, Lutgard DeJonghe, and Craig Jacobson have developed a simple, inexpensive method for producing high density, crack-free, thin ceramic ...

231

047 Glass-Ceramic Composites for High Energy Density Capacitors  

Science Conference Proceedings (OSTI)

047 Glass-Ceramic Composites for High Energy Density Capacitors .... 150 Analysis of Hf-Ta Alloys for Oxidation Protection in Ultra High Temperature ...

232

Vibrated Bulk Density (VBD) of Calcined Petroleum Coke and ...  

Science Conference Proceedings (OSTI)

Presentation Title, Vibrated Bulk Density (VBD) of Calcined Petroleum Coke and Implications of Changes in the ASTM Method D4292. Author(s), Bill Spencer, ...

233

Compressive Properties of Low Relative Density Materials, Both ...  

Science Conference Proceedings (OSTI)

Abstract Scope, The compressive constitutive behavior of low relatively density materials bas been characterized for various materials. It has been seen that ...

234

Aluminum Oxynitride Dielectrics for High Energy Density Capacitor ...  

Science Conference Proceedings (OSTI)

Oct 15, 2006 ... Aluminum Oxynitride Dielectrics for High Energy Density Capacitor Applications by Kevin R. Bray, Richard L.C. Wu, Sandra Fries-Carr, and ...

235

Hybrid Aluminum-Lithium Ion Battery having Enhanced Power Density  

Hybrid Aluminum-Lithium Ion Battery having Enhanced Power Density Note: The technology described above is an early stage opportunity. Licensing rights to this ...

236

Device Fabrication Method for High Power Density Capacitors  

Device Fabrication Method for High Power Density Capacitors Note: The technology described above is an early stage opportunity. Licensing rights to this intellectual ...

237

3-D capacitance density imaging of fluidized bed  

DOE Patents (OSTI)

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.

Fasching, George E. (653 Vista Pl., Morgantown, WV 26505)

1990-01-01T23:59:59.000Z

238

CORRELATION BETWEEN GROUP LOCAL DENSITY AND GROUP LUMINOSITY  

SciTech Connect

In this study, we investigate the correlation between group local number density and total luminosity of groups. In four volume-limited group catalogs, we can conclude that groups with high luminosity exist preferentially in high-density regions, while groups with low luminosity are located preferentially in low-density regions, and that in a volume-limited group sample with absolute magnitude limit M{sub r} = -18, the correlation between group local number density and total luminosity of groups is the weakest. These results basically are consistent with the environmental dependence of galaxy luminosity.

Deng Xinfa [School of Science, Nanchang University, Jiangxi 330031 (China); Yu Guisheng [Department of Natural Science, Nanchang Teachers College, Jiangxi 330103 (China)

2012-11-10T23:59:59.000Z

239

Amplifying Magnetic Fields in High Energy Density Plasmas | U...  

Office of Science (SC) Website

Amplifying Magnetic Fields in High Energy Density Plasmas Fusion Energy Sciences (FES) FES Home About Research Facilities Science Highlights Benefits of FES Funding Opportunities...

240

HIGH ENERGY DENSITY ALUMINUM BATTERY - Energy Innovation Portal  

Compositions and methods of making are provided for a high energy density aluminum battery. The battery comprises an anode comprising aluminum metal. The battery ...

Note: This page contains sample records for the topic "activity population density" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


241

Beat-wave heating with density profile steepening  

SciTech Connect

Electron heating by the beat between 0.53 and 1.06 ..mu..m light in a self-consistently steepened density profile is examined.

Kruer, W.L.; Estabrook, K.

1986-10-01T23:59:59.000Z

242

Optimization Online - The Reduced Density Matrix Method for ...  

E-Print Network (OSTI)

Oct 16, 2003 ... The Reduced Density Matrix Method for Electronic Structure Calculations ... Calculations of the ground state energy and the dipole moment are ...

243

Mobility of electrons in supercritical krypton: Role of density...  

NLE Websites -- All DOE Office Websites (Extended Search)

in the scattering cross section at an intermediate field strength. A minimum in the electron mobility was observed at about one-half the critical density. The acoustical...

244

Anomalously High Density of Adsorbed Hydrogen on Surface ...  

Science Conference Proceedings (OSTI)

The amount of adsorbed hydrogen at 20 K under relative pressure = 0.9 was about 11 mass%, indicating that the hydrogen density of the adsorbed state should ...

245

The Materials Project: Combining Density Functional Theory Calculation...  

NLE Websites -- All DOE Office Websites (Extended Search)

The Materials Project The Materials Project: Combining Density Functional Theory Calculations with Supercomputing Centers for New Materials Discovery May 2, 2013 jain2 Anubhav Jain...

246

Population viability analysis of the Endangered shortnose sturgeon  

Science Conference Proceedings (OSTI)

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.

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

2011-07-01T23:59:59.000Z

247

Active security  

Science Conference Proceedings (OSTI)

In this paper we introduce active security, a new methodology which introduces programmatic control within a novel feedback loop into the defense infrastructure. Active security implements a unified programming environment which provides interfaces ... Keywords: central management, digital forensics, network security

Ryan Hand, Michael Ton, Eric Keller

2013-11-01T23:59:59.000Z

248

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

Science Conference Proceedings (OSTI)

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.

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

249

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

DOE Green Energy (OSTI)

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.

Stark, Eric J.

2008-12-18T23:59:59.000Z

250

Density Functional Theory Calculations of Mass Transport in UO2  

SciTech Connect

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.

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

251

The Stellar Populations of Seyfert 2 Nuclei  

E-Print Network (OSTI)

We present a preliminary analysis of the stellar populations in the central parsecs of a sample of 22 Seyfert 2 galaxies, based on a careful separation of nebular emission and stellar light in high-spatial resolution HST-STIS spectra. 10% of the surveyed nuclei display stellar populations of intermediate age, 1-2 Gyr old, whereas the remaining targets appear to be evenly split between objects showing only very old stellar populations and nuclei requiring also an additional blue featureless component, which we characterise by means of very young, few-Myr-old stars. The small fraction of stellar population of intermediate age seems to argue against the presence of such a young component, however, since the short lifetime of O-stars would imply recurrent star-formation episodes and the build-up over the last 1-2 Gyr of a detectable intermediate-age population. Additionally, a correlation between the luminosity of such a blue component and the emission from highly-ionised species, together with the general absence of Wolf-Rayet features, further suggests that the featureless continuum arises from the central engine rather than from star-forming regions. We discuss our results in the framework of the unification paradigm and of models for star formation close to supermassive black holes.

Marc Sarzi; Joe Shields; Rick Pogge; Paul Martini

2007-03-30T23:59:59.000Z

252

The Biermann Battery in Cosmological MHD Simulations of Population III Star Formation  

E-Print Network (OSTI)

We report the results of the first self-consistent three-dimensional adaptive mesh refinement magnetohydrodynamical simulations of Population III star formation including the Biermann Battery effect. We find that the Population III stars formed including this effect are both qualitatively and quantitatively similar to those from hydrodynamics-only (non-MHD) cosmological simulations. We observe peak magnetic fields of ~10^-9 G in the center of our star-forming halo at z ~ 17.55. The magnetic fields created by the Biermann Battery effect are predominantly formed early in the evolution of the primordial halo at low density and large spatial scales, and then grow through compression and by shear flows. The fields seen in this calculation are never large enough to be dynamically important (with beta >= 10^{15} at all times), and should be considered the minimum possible fields in existence during Population III star formation, and may be seed fields for the stellar dynamo or the magnetorotational instability at higher densities and smaller spatial scales.

Hao Xu; Brian W. O'Shea; David C. Collins; Michael L. Norman; Hui Li; Shengtai Li

2008-07-16T23:59:59.000Z

253

Mixed Layer Density Ratio from the Levitus Data  

Science Conference Proceedings (OSTI)

An analysis of the Levitus data is employed to examine Stommel's mixed layer density ratio regulator hypothesis. Three different methods of computing the lateral density ratio (Rl???T/??S) are used and the least squares method was found to have ...

Liang Gui Chen

1995-04-01T23:59:59.000Z

254

Energy density for chiral lattice fermions with chemical potential  

E-Print Network (OSTI)

We study a recently proposed formulation of overlap fermions at finite density. In particular we compute the energy density as a function of the chemical potential and the temperature. It is shown that overlap fermions with chemical potential reproduce the correct continuum behavior.

Gattringer, Christof

2007-01-01T23:59:59.000Z

255

STRAIGHTENING THE DENSITY-DISPLACEMENT RELATION WITH A LOGARITHMIC TRANSFORM  

Science Conference Proceedings (OSTI)

We investigate the use of a logarithmic density variable in estimating the Lagrangian displacement field motivated by the success of a logarithmic transformation in restoring information to the matter power spectrum. The logarithmic relation is an extension of the linear relation, motivated by the continuity equation, in which the density field is assumed to be proportional to the divergence of the displacement field; we compare the linear and logarithmic relations by measuring both of these fields directly in a cosmological N-body simulation. The relative success of the logarithmic and linear relations depends on the scale at which the density field is smoothed. Thus we explore several ways of measuring the density field, including Cloud-In-Cell smoothing, adaptive smoothing, and the (scale-independent) Delaunay tessellation, and we use both a Fourier-space and a geometrical tessellation approach to measuring the divergence. We find that the relation between the divergence of the displacement field and the density is significantly tighter and straighter with a logarithmic density variable, especially at low redshifts and for very small ({approx}2 h{sup -1} Mpc) smoothing scales. We find that the grid-based methods are more reliable than the tessellation-based method of calculating both the density and the divergence fields, though in both cases the logarithmic relation works better in the appropriate regime, which corresponds to nonlinear scales for the grid-based methods and low densities for the tessellation-based method.

Falck, Bridget L.; Neyrinck, Mark C.; Aragon-Calvo, Miguel A.; Lavaux, Guilhem; Szalay, Alexander S. [Department of Physics and Astronomy, Johns Hopkins University, 3400 North Charles St., Baltimore, MD 21218 (United States)

2012-01-20T23:59:59.000Z

256

Measurement on CO_2 Solution Density by Optical Technology  

Science Conference Proceedings (OSTI)

The optical technology based on Mach-Zehnder interferometry was successfully applied to a high-pressure liquid CO_2 and water system to measure CO_2 solution density. Experiments were carried out at a pressure range of from 5.0 to 12.5 MPa, temperatures ... Keywords: CO_2 ocean sequestration, CO_2 solution, Mach-Zehnder Interferometry, density

Y. Song; M. Nishio; B. Chen; S. Someya; T. Ohsumi

2003-01-01T23:59:59.000Z

257

OPTIMIZATION OF LAYER DENSITIES FOR MULTILAYERED INSULATION SYSTEMS  

Science Conference Proceedings (OSTI)

Numerous tests of various multilayer insulation systems have indicated that there are optimal densities for these systems. However, the only method of calculating this optimal density was by a complex physics based algorithm developed by McIntosh. In the 1970's much data were collected on the performance of these insulation systems with many different variables analyzed. All formulas generated included number of layers and layer density as geometric variables in solving for the heat flux, none of them was in a differentiable form for a single geometric variable. It was recently discovered that by converting the equations from heat flux to thermal conductivity using Fourier's Law, the equations became functions of layer density, temperatures, and material properties only. The thickness and number of layers of the blanket were merged into a layer density. These equations were then differentiated with respect to layer density. By setting the first derivative equal to zero, and solving for the layer density, the critical layer density was determined. This method was checked and validated using test data from the Multipurpose Hydrogen Testbed which was designed using Mcintosh's algorithm.

Johnson, W. L. [NASA Kennedy Space Center, KT-E Kennedy Space Center, FL 32899 (United States)

2010-04-09T23:59:59.000Z

258

The spectral density of the scattering matrix for high energies  

E-Print Network (OSTI)

We determine the density of eigenvalues of the scattering matrix of the Schrodinger operator with a short range potential in the high energy asymptotic regime. We give an explicit formula for this density in terms of the X-ray transform of the potential.

Daniel Bulger; Alexander Pushnitski

2011-10-17T23:59:59.000Z

259

The spectral density of the scattering matrix for high energies  

E-Print Network (OSTI)

We determine the density of eigenvalues of the scattering matrix of the Schrodinger operator with a short range potential in the high energy asymptotic regime. We give an explicit formula for this density in terms of the X-ray transform of the potential.

Bulger, Daniel

2011-01-01T23:59:59.000Z

260

Generalized Look-Ahead Methods for Computing Stationary Densities  

Science Conference Proceedings (OSTI)

The look-ahead estimator is used to compute densities associated with Markov processes via simulation. We study a framework that extends the look-ahead estimator to a broader range of applications. We provide a general asymptotic theory for the estimator, ... Keywords: densities, numerical methods, simulation

R. Anton Braun; Huiyu Li; John Stachurski

2012-08-01T23:59:59.000Z

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261

Dynamical instabilities in density-dependent hadronic relativistic models  

Science Conference Proceedings (OSTI)

Unstable modes in asymmetric nuclear matter (ANM) at subsaturation densities are studied in the framework of relativistic mean-field density-dependent hadron models. The size of the instabilities that drive the system are calculated and a comparison with results obtained within the nonlinear Walecka model is presented. The distillation and antidistillation effects are discussed.

Santos, A. M.; Brito, L.; Providencia, C. [Centro de Fisica Teorica, Department of Physics, University of Coimbra, P-3004-516 Coimbra (Portugal)

2008-04-15T23:59:59.000Z

262

Alternative representation of N \\times N density matrix  

E-Print Network (OSTI)

We use polarization operators known from quantum theory of angular momentum to expand the $N \\times N$ dimensional density operators. Thereby, we construct generalized Bloch vectors representing density matrices. We study their properties and derive positivity conditions for any $N$. We also apply the procedure to study Bloch vector space for a qubit and a qutrit.

Stanislaw Kryszewski; Mateusz Zachcial

2006-02-06T23:59:59.000Z

263

Density Changes in Plutonium Observed from Accelerated Aging Using Pu-238 Enrichment  

Science Conference Proceedings (OSTI)

In support of Stockpile Stewardship activities, accelerated aging tests on a plutonium alloy enriched with 7.3 atomic percentage of {sup 238}Pu is underway using dilatometry at 35, 50, and 65 C and immersion density measurements of material stored at 50 C. Changes in density are expected from radiation damage in the lattice and helium in-growth. After twenty-five equivalent years of aging, the dilatometry data shows that the alloys at 35 C have expanded in volume by 0.11% to 0.12% and have started to exhibit a near linear expansion behavior primarily caused by the helium accumulation. The average He-to-vacancy ratio from tested specimens was determined to be around 2.3. The model for the lattice damage and helium in-growth accurately represents the volume swelling at 35 C. The density converted from the dilatometry corresponds well to the decreasing density trend of reference plutonium alloys as a function of time.

Chung, B W; Thompson, S R; Woods, C H; Hopkins, D J; Gourdin, W H; Ebbinghaus, B B

2005-10-19T23:59:59.000Z

264

Innovative High Energy Density Capacitor Design Offers Potential for Clean  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Innovative High Energy Density Capacitor Design Offers Potential Innovative High Energy Density Capacitor Design Offers Potential for Clean Energy Applications Innovative High Energy Density Capacitor Design Offers Potential for Clean Energy Applications June 10, 2011 - 4:46pm Addthis Similar system to the clustering tool that will manufacture TroyCap’s High Energy Density Nanolaminate Capacitor | Credit: TroyC Similar system to the clustering tool that will manufacture TroyCap's High Energy Density Nanolaminate Capacitor | Credit: TroyC Ben Squires Analyst, Office of Energy Efficiency & Renewable Energy Can you imagine a photovoltaic module that's able to generate and store electricity on its own? Or an electric vehicle (EV) powered by a technology more durable than the advanced batteries in today's EVs? Malvern,

265

Innovative High Energy Density Capacitor Design Offers Potential for Clean  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

High Energy Density Capacitor Design Offers Potential High Energy Density Capacitor Design Offers Potential for Clean Energy Applications Innovative High Energy Density Capacitor Design Offers Potential for Clean Energy Applications June 10, 2011 - 4:46pm Addthis Similar system to the clustering tool that will manufacture TroyCap’s High Energy Density Nanolaminate Capacitor | Credit: TroyC Similar system to the clustering tool that will manufacture TroyCap's High Energy Density Nanolaminate Capacitor | Credit: TroyC Ben Squires Analyst, Office of Energy Efficiency & Renewable Energy Can you imagine a photovoltaic module that's able to generate and store electricity on its own? Or an electric vehicle (EV) powered by a technology more durable than the advanced batteries in today's EVs? Malvern, Pennsylvania's TroyCap, LLC is using nanolaminate technology patented by

266

Modeling Population Exposures to Pollutants Emitted From Natural...  

NLE Websites -- All DOE Office Websites (Extended Search)

Modeling Population Exposures to Pollutants Emitted From Natural Gas Cooking Burners Title Modeling Population Exposures to Pollutants Emitted From Natural Gas Cooking Burners...

267

Tracer populations in the local group  

E-Print Network (OSTI)

, in good agreement with previous work. I go on to develop a set of tracer mass estimators that build on previous work which make use of actual (and not projected) distance and proper motion data, reflecting the amount and quality of data now available to us... ages range from 1-10 Gyr; the scale height of the population increases with age from 200 kpc to around 700 kpc and the metallicity decreases with age to around 20% solar. The typical content of this disk population are A stars, planetary nebulae...

Watkins, Laura Louise

2011-04-19T23:59:59.000Z

268

Recent advances in the use of density functional theory to design efficient solar energy-based renewable systems  

Science Conference Proceedings (OSTI)

This article reviews the use of Density Functional Theory (DFT) to study the electronic and optical properties of solar-active materials and dyes used in solar energy conversion applications (dye-sensitized solar cells and water splitting). We first give a brief overview of the DFT its development

Ramy Nashed; Yehea Ismail; Nageh K. Allam

2013-01-01T23:59:59.000Z

269

Use of Density Equalizing Map Projections (DEMP) in the analysis of childhood cancer in four California counties. Revision 2  

Science Conference Proceedings (OSTI)

In studying geographic disease distributions, one normally compares rates among arbitrarily defined geographic subareas (e.g. census tracts), thereby sacrificing 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). 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 rates are constant. The present report describes the application of the DEMP technique to 401 childhood cancer cases occurring between 1980 and 1988 in four California counties, with the use of map files and population data for the 262 tracts of the 1980 Census. A k`th nearest neighbor analysis provides strong evidence for geographic non-uniformity in tract rates (p < 10{sup {minus}4}). No such effect is observed for artificial cases generated under the assumption of constant rates. Work is in progress to repeat the analysis with improved population estimates derived from both 1980 and 1990 Census data. Final epidemiologic conclusions will be reported when that analysis is complete.

Merrill, D.W.; Close, E.R.; Holmes, H.H. [Lawrence Berkeley Lab., CA (United States); Selvin, S. [Lawrence Berkeley Lab., CA (United States)]|[Univ. of California, Berkeley, CA (United States). School of Public Health

1995-10-01T23:59:59.000Z

270

What causes the density effect in young forest plantations?  

DOE Green Energy (OSTI)

In young forest plantations, trees planted at high densities frequently show more rapid height and diameter growth than those plants at lower densities. This positive growth response to density (the ''density effect'') often manifests long before seedlings are tall enough to shade one another, so it is not a simple response to shade. The mechanism(s) which trigger and sustain this growth enhancement are unknown. Our objectives were to document the temporal dynamics of positive growth response to increasing density in Douglas-fir plantations and to test two hypotheses as potential mechanisms for this response. The hypotheses are (1) a canopy boundary layer effect, and (2) alterations in the quality of light reflected from neighboring trees. The ''boundary layer'' hypotheses proposes that changes in atmospheric mixing occur in high-density plantations, promoting increased concentrations of CO{sub 2} and H{sub 2}O vapor during early morning hours, which in turn would enhance carbon assimilation. The ''light quality'' hypothesis proposes that the presence of neighbors alters the ratio of red to far red light in the canopy environment. Plant sensors detect this change in light quality, and growth and development is altered in response. We found that boundary layer conductance was higher, as we predicted, in low-density Douglas-fir stands than in high-density stands five years after planting. The changes in boundary conductance were accompanied by higher CO{sub 2} and H{sub 2}O vapor during early morning hours. However, we also found that the primary manifestation of the density effect in Douglas-fir occurs two to four years after planting, and we were not able to measure differences in boundary conductance in different densities at that time. Also, we found no difference in carbon isotope composition of wood cellulose formed in high- vs. low-density stands two to three years after planting. We conclude that although stand density may have a significant impact on boundary layer conductance in young stands, it does not account for the ''density effect''. Our tests of the light quality hypothesis were slowed due to poor plantation establishment in the early phase of this study. In a variable density experiment we detected significant changes in R:FR related to density. Also in that study we measured a significant enhancement of tree height at high density. However, after three years of growth, the study trees did not show significant differences in stem diameter related to density. Experimenters at Weyerhaeuser therefore decided not to harvest the trees at the end of the 3rd growth year, as originally planned. In a 1-year study of seedlings planted in raised beds subjected to different light quality treatments using transparent plastic film, we found that tree height but not diameter increased in response to decreased R:FR. At this point, we conclude that R:FR remains a viable hypothesis for the ''density effect'', but evidence is not conclusive. We expect that continued measurements in the variable density test plot at Weyerhaeuser will add more evidence in the future.

Barbara J. Bond; Gary A. Ritchie

2002-07-21T23:59:59.000Z

271

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

DOE Green Energy (OSTI)

This report summarizes the work done during the eleventh quarter of the project. Conductivity relaxation experiments were conducted on porous La{sub 0.5}Sr{sub 0.5}CoO{sub (3-{delta})} (LSC50) samples over a temperature range from 350 to 750 C, and over an oxygen partial pressure, p{sub O{sub 2}}, switch between 0.04 and 0.06 atm in order to determine the surface exchange coefficient, k{sub chem}. The normalized conductivity data could be fitted to a first order kinetic equation. The time constant decreased with decreasing temperature between {approx}750 and {approx}450 C, but sharply increased with decreasing temperature between 450 and 350 C. The corresponding k{sub chem} was estimated using three models: (a) A porous body model wherein it is assumed that the kinetics of surface exchange is the slowest. (b) Solution to the diffusion equation assuming the particles can be approximated as spheres. (c) Solution to the diffusion equation assuming the particles can be approximated as cylinders. The values of k{sub chem} obtained from the three models were in good agreement. In all cases, it was observed that k{sub chem} increases with decreasing temperature between 750 and 450 C, but below 450 C, it sharply decreases with further decrease in temperature.

Anil V. Virkar

2005-09-21T23:59:59.000Z

272

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

DOE Green Energy (OSTI)

This report summarizes the work done during the fifth quarter of the project. Effort was directed in two 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) Fabrication of porous samaria-doped ceria (SDC) and investigation of the effect of thermal treatment on its conductivity. The model developed accounts for transport through three regions: (a) Transport through the bulk of the grain, RI, which includes parallel transport through space charge region. (b) Transport through the space charge region adjacent to the neck (grain boundary), RII. (c) Transport through the structural part of the neck (grain boundary), RIII. The work on the model development involves calculation RI, RII, RIII, and the sum of these three terms, which is the total resistance, as a function of the grain radius ranging between 0.5 and 5 microns and as a function of the relative neck size, described in terms of the angle theta, ranging between 5 and 45{sup o}. Three values of resistivity of the space charge region were chosen; space charge resistivity greater than grain resistivity, equal to grain resistivity, and lower than grain resistivity. Experimental work was conducted on samaria (Sm{sub 2}O{sub 3})-doped ceria (SDC) samples of differing porosity levels, before and after thermal treatment at 1200 C. The conductivity in the annealed samples was lower, consistent with enhanced Debye length. This shows the important role of space charge on ionic transport, and its implications concerning cathode polarization.

Anil V. Virkar

2004-03-08T23:59:59.000Z

273

HIGH-DENSITY MOLECULAR GAS PROPERTIES OF THE STARBURST GALAXY NGC 1614 REVEALED WITH ALMA  

Science Conference Proceedings (OSTI)

We present the results of HCN/HCO{sup +}/HNC J = 4-3 transition line observations of the nearby starburst galaxy NGC 1614, obtained with ALMA Cycle 0. We find that high density molecular gas traced with these lines shows a velocity structure such that the northern (southern) side of the nucleus is redshifted (blueshifted) with respect to the nuclear velocity of this galaxy. The redshifted and blueshifted emission peaks are offset by {approx}0.''6 at the northern and southern sides of the nucleus, respectively. At these offset positions, observations at infrared >3 {mu}m indicate the presence of active dusty starbursts, supporting the picture that high-density molecular gas is the site of active starbursts. The enclosed dynamical mass within the central {approx}2'' in radius, derived from the dynamics of the high-density molecular gas, is {approx}10{sup 9} M{sub Sun }, which is similar to previous estimates. Finally, the HCN emission is weaker than HCO{sup +} but stronger than HNC for J = 4-3 for all starburst regions of NGC 1614, as seen for J = 1-0 transition lines in starburst-dominated galaxies.

Imanishi, Masatoshi [Subaru Telescope, 650 North A'ohoku Place, Hilo, HI 96720 (United States); Nakanishi, Kouichiro, E-mail: masa.imanishi@nao.ac.jp [Joint ALMA Observatory, Alonso de Cordova 3107, Vitacura 763-0355, Santiago (Chile)

2013-09-15T23:59:59.000Z

274

Molecular analysis of the metabolic rates of discrete subsurface populations of sulfate reducers  

SciTech Connect

Elucidating the in situ metabolic activity of phylogenetically diverse populations of sulfate-reducing microorganisms that populate anoxic sedimentary environments is key to understanding subsurface ecology. Previous pure culture studies have demonstrated that transcript abundance of dissimilatory (bi)sulfite reductase genes is correlated with the sulfate reducing activity of individual cells. To evaluate whether expression of these genes was diagnostic for subsurface communities, dissimilatory (bi)sulfite reductase gene transcript abundance in phylogenetically distinct sulfate-reducing populations was quantified during a field experiment in which acetate was added to uranium-contaminated groundwater. Analysis of dsrAB sequences prior to the addition of acetate indicated that Desulfobacteraceae, Desulfobulbaceae, and Syntrophaceae-related sulfate reducers were the most abundant. Quantifying dsrB transcripts of the individual populations suggested that Desulfobacteraceae initially had higher dsrB transcripts per cell than Desulfobulbaceae or Syntrophaceae populations, and that the activity of Desulfobacteraceae increased further when the metabolism of dissimilatory metal reducers competing for the added acetate declined. In contrast, dsrB transcript abundance in Desulfobulbaceae and Syntrophaceae remained relatively constant, suggesting a lack of stimulation by added acetate. The indication of higher sulfate-reducing activity in the Desulfobacteraceae was consistent with the finding that Desulfobacteraceae became the predominant component of the sulfate-reducing community. Discontinuing acetate additions resulted in a decline in dsrB transcript abundance in the Desulfobacteraceae. These results suggest that monitoring transcripts of dissimilatory (bi)sulfite reductase genes in distinct populations of sulfate reducers can provide insight into the relative rates of metabolism of different components of the sulfate-reducing community and their ability to respond to environmental perturbations.

Miletto, M.; Williams, K.H.; N'Guessan, A.L.; Lovley, D.R.

2011-04-01T23:59:59.000Z

275

Density Changes in the Optimized CSSX Solvent System  

Science Conference Proceedings (OSTI)

Density increases in caustic-side solvent extraction (CSSX) solvent have been observed in separate experimental programs performed by different groups of researchers. Such changes indicate a change in chemical composition. Increased density adversely affects separation of solvent from denser aqueous solutions present in the CSSX process. Identification and control of factors affecting solvent density are essential for design and operation of the centrifugal contactors. The goals of this research were to identify the factors affecting solvent density (composition) and to develop correlations between easily measured solvent properties (density and viscosity) and the chemical composition of the solvent, which will permit real-time determination and adjustment of the solvent composition. In evaporation experiments, virgin solvent was subjected to evaporation under quiescent conditions at 25, 35, and 45 C with continuously flowing dry air passing over the surface of the solvent. Density and viscosity were measured periodically, and chemical analysis was performed on the solvent samples. Chemical interaction tests were completed to determine if any chemical reaction takes place over extended contact time that changes the composition and/or physical properties. Solvent and simulant, solvent and strip solution, and solvent and wash solution were contacted continuously in agitated flasks. They were periodically sampled and the density measured (viscosity was also measured on some samples) and then submitted to the Chemical Sciences Division of Oak Ridge National Laboratory for analysis by nuclear magnetic resonance (NMR) spectrometry and high-performance liquid chromatography (HPLC) using the virgin solvent as the baseline. Chemical interaction tests showed that solvent densities and viscosities did not change appreciably during contact with simulant, strip, or wash solution. No effects on density and viscosity and no chemical changes in the solvent were noted within experimental limits. Evaporation test results showed that all solvents were evaporated to densities of greater than 0.90 g/cm{sup 3}. Viscosities increased from 3.5 to >6.5 cP as the densities increased. NMR and HPLC data indicate that diluent loss is the primary reason for density increase and that the ratio of BOBCalixC6 (referred to as calix) to Cs-7SB remained almost constant. Density and viscosity vary linearly with the loss of diluent and the increase in Cs-7SB concentration. Solvent viscosity and density are both sensitive indicators of the loss of diluent, especially when such loss is greater than 10%. However, density is more reliable at low values for diluent loss. The ratio of Cs-7SB to calix appears relatively constant during evaporation to losses of more than 50% of the diluent. A simple density model accurately predicts the composition of the solvent when density is known. Density and viscosity increases can affect the throughput in the centrifugal contactors and, at the extreme, can cause complete loss of flow. The distribution coefficient can also increase, especially in the strip stage, causing the loss of the ability to strip extracted cesium from the solvent. These effects can be addressed by internal changes to the contactor and by adding additional stripping stages in processing. However, these changes are extremely difficult under remote operation and maintenance restrictions.

Lee, D.D.

2002-11-25T23:59:59.000Z

276

Energy implications of an aging population  

Science Conference Proceedings (OSTI)

This study provides various demographic, medical, and economic information relative to energy usage on a segment of the population, the elderly, which is growing in absolute numbers and relative population percentage. This growth is expected to continue well into the twenty-first century. The US aging population numbered 3.1 million in 1900, and by 1977 it had climbed to 23.5 million. It can be stated with reasonable certainty that this figure will rise to 31 million in the year 2000 and 43 million in the year 2020. These figures, corresponding to more than 10% of our population, are by no means insignificant. As our fossil-fuel reserves are being depleted and the cost of energy mounts, it becomes apparent that the elderly will become increasingly vulnerable to the energy crisis, primarily beause of their physical tendency to infirmity, their economic and social situation, and their susceptibility to psychological depression. This white paper concentrates on those aspects of aging and the nation's energy problem which are not usually related in our everyday consideration of these as separable problems. It seeks to identify the peculiar energy problems of the aged and to consider alternatives in the solution of these problems in light of modern technology.

Not Available

1980-08-01T23:59:59.000Z

277

Atlantic Bluefin Tuna (Thunnus thynnus) Population Dynamics  

E-Print Network (OSTI)

Atlantic Bluefin Tuna (Thunnus thynnus) Population Dynamics Delineated by Organochlorine Tracers R bluefin tuna (ABFT) are highly valued and heavily exploited, and critical uncertainties regarding. Hereweshowthatorganochlorinepesticidesandpolychlorinated biphenyls (PCBs) can be used as tracers of bluefin tuna foraging grounds in the North Atlantic

Hilton, Eric J.

278

Ontology-driven, unsupervised instance population  

Science Conference Proceedings (OSTI)

The Semantic Web's need for machine understandable content has led researchers to attempt to automatically acquire such content from a number of sources, including the web. To date, such research has focused on ''document-driven'' systems that individually ... Keywords: Classification, Confidence assessment, Instance population, Ontology-driven, Semantic Web

Luke K. McDowell; Michael Cafarella

2008-09-01T23:59:59.000Z

279

Adaptive Evolution and Effective Population Size in Wild House Mice  

E-Print Network (OSTI)

Estimates of the proportion of amino acid substitutions that have been fixed by selection (a) vary widely among taxa, ranging from zero in humans to over 50 % in Drosophila. This wide range may reflect differences in the efficacy of selection due to differences in the effective population size (Ne). However, most comparisons have been made among distantly related organisms that differ not only in Ne but also in many other aspects of their biology. Here, we estimate a in three closely related lineages of house mice that have a similar ecology but differ widely in Ne: Mus musculus musculus (Ne; 25,000–120,000), M. m. domesticus (Ne; 58,000–200,000), and M. m. castaneus (Ne; 200,000–733,000). Mice were genotyped using a high-density single nucleotide polymorphism array, and the proportions of replacement and silent mutations within subspecies were compared with those fixed between each subspecies and an outgroup, Mus spretus. There was significant evidence of positive selection in M. m. castaneus, the lineage with the largest Ne, with a estimated to be approximately 40%. In contrast, estimates of a for M. m. domesticus (a 5 13%) and for M. m. musculus (a 5 12 %) were much smaller. Interestingly, the higher estimate of a for M. m. castaneus appears to reflect not only more adaptive fixations but also more effective purifying selection. These results support the hypothesis that differences in Ne contribute to differences among species in the efficacy of selection.

Megan Phifer-rixey; Francxois Bonhomme; Pierre Boursot; Gary A. Churchill; Jaroslav Piálek; Priscilla K. Tucker; Michael W. Nachman

2012-01-01T23:59:59.000Z

280

A short remark on negative energy densities and quantum inequalities  

E-Print Network (OSTI)

In quantum field theory it is generally known that the energy density may be negative at a given point in spacetime. A number of papers have shown that there is a restriction on this energy density which is called a quantum inequality (QI). A QI is the lower bound to the "weighted average" of the energy density at a given point integrated over a time dependent sampling function. In this paper we give an example of a sampling function for which there is no QI.

Solomon, Dan

2009-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "activity population density" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
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281

A short remark on negative energy densities and quantum inequalities  

E-Print Network (OSTI)

In quantum field theory it is generally known that the energy density may be negative at a given point in spacetime. A number of papers have shown that there is a restriction on this energy density which is called a quantum inequality (QI). A QI is the lower bound to the "weighted average" of the energy density at a given point integrated over a time dependent sampling function. In this paper we give an example of a sampling function for which there is no QI.

Dan Solomon

2009-01-05T23:59:59.000Z

282

Nuclear Energy Density Functionals Constrained by Low-Energy QCD  

E-Print Network (OSTI)

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.

Vretenar, Dario

2008-01-01T23:59:59.000Z

283

Nuclear Energy Density Functionals Constrained by Low-Energy QCD  

E-Print Network (OSTI)

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.

Dario Vretenar

2008-02-06T23:59:59.000Z

284

Sensitivity of nuclear stopping towards density dependent symmetry energy  

E-Print Network (OSTI)

The effect of density dependent symmetry energy on nuclear-stopping is studied using isospin-dependent quantum molecular dynamics model(IQMD). We have used the reduced isospin-dependent cross-section with soft(S) equation of state for the systems having different isostopic content, to explore the various aspects of nuclear stopping. The aim is to pin down the nature of the nuclear stopping with density dependent symmetry energy. Nuclear stopping is found to be sensitive towards the various forms of the density dependent symmetry energy. The nuclear stopping tends to decrease for the stiffer equation of state (EOS), i.e. larger values of gamma.

Karan Singh Vinayak; Suneel Kumar

2011-10-11T23:59:59.000Z

285

Symmetry energy at subnuclear densities deduced from nuclear masses  

E-Print Network (OSTI)

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.

Oyamatsu, Kazuhiro

2010-01-01T23:59:59.000Z

286

Symmetry energy at subnuclear densities deduced from nuclear masses  

E-Print Network (OSTI)

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.

Kazuhiro Oyamatsu; Kei Iida

2010-02-23T23:59:59.000Z

287

Sensitivity of nuclear stopping towards density dependent symmetry energy  

E-Print Network (OSTI)

The effect of density dependent symmetry energy on nuclear-stopping is studied using isospin-dependent quantum molecular dynamics model(IQMD). We have used the reduced isospin-dependent cross-section with soft(S) equation of state for the systems having different isostopic content, to explore the various aspects of nuclear stopping. The aim is to pin down the nature of the nuclear stopping with density dependent symmetry energy. Nuclear stopping is found to be sensitive towards the various forms of the density dependent symmetry energy. The nuclear stopping tends to decrease for the stiffer equation of state (EOS), i.e. larger values of gamma.

Vinayak, Karan Singh

2011-01-01T23:59:59.000Z

288

Density effect on relativistic electron beams in a plasma fiber  

Science Conference Proceedings (OSTI)

Intense short-petawatt-laser driven relativistic electron beams in a hollow high-Z plasma fiber embedded in low-Z plasmas of different densities are studied. When the plasma is of lower density than the hollow fiber, resistive filamentation of the electron beam is observed. It is found that the electron motion and the magnetic field are highly correlated with tens of terahertz oscillation frequency. Depending on the material property around the hollow fiber and the plasma density, the beam electrons can be focused or defocused as it propagates in the plasma. Relativistic electron transport and target heating are also investigated.

Zhou, C. T.; He, X. T. [Institute of Applied Physics and Computational Mathematics, Beijing 100094 (China); Center for Applied Physics and Technology, Peking University, Beijing 100871 (China); Institute for Fusion Theory and Simulation, Zhejiang University, Hangzhou 310027 (China); Wang, X. G. [Institute for Fusion Theory and Simulation, Zhejiang University, Hangzhou 310027 (China); Wu, S. Z. [Institute of Applied Physics and Computational Mathematics, Beijing 100094 (China); Cai, H. B. [Institute of Applied Physics and Computational Mathematics, Beijing 100094 (China); Center for Applied Physics and Technology, Peking University, Beijing 100871 (China); Wang, F. [Center for Applied Physics and Technology, Peking University, Beijing 100871 (China)

2010-11-15T23:59:59.000Z

289

Integrated data analysis at TJ-II: The density profile  

SciTech Connect

An integrated data analysis system based on Bayesian inference has been developed for the TJ-II stellarator. It reconstructs the electron density profile at a single time point, using data from interferometry, reflectometry, Thomson scattering, and the Helium beam, while providing a detailed error analysis. In this work, we present a novel analysis of the ambiguity inherent in profile reconstruction from reflectometry and show how the integrated data analysis approach elegantly resolves it. Several examples of the application of the technique are provided, in both low-density discharges with and without electrode biasing, and in high-density discharges with an (L-H) confinement transition.

Milligen, B. Ph. van; Estrada, T.; Ascasibar, E.; Tafalla, D.; Lopez-Bruna, D.; Fraguas, A. Lopez; Jimenez, J. A.; Garcia-Cortes, I. [Asociacion EURATOM-CIEMAT para Fusion, Avda. Complutense 22, 28040 Madrid (Spain); Dinklage, A. [Max-Planck-Institut fuer Plasmaphysik, Teilinstitut Greifswald, EURATOM Association, Wendelsteinstr. 1, 17 491 Greifswald (Germany); Fischer, R. [Max-Planck-Institut fuer Plasmaphysik, EURATOM Association, Boltzmannstr. 2, D-85748 Garching (Germany)

2011-07-15T23:59:59.000Z

290

Catalyst activator  

DOE Patents (OSTI)

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.

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

291

Population Synthesis of Radio and Gamma-ray Pulsars in the Fermi Era  

E-Print Network (OSTI)

We present results of our pulsar population synthesis of normal pulsars from the Galactic disk using our previously developed computer code. On the same footing, we use slot gap and outer gap models for gamma-ray emission from normal pulsars to obtain statistics of radio-loud and radio-quiet gamma-ray pulsars. From recently improved understanding of HII and star forming regions in the Galaxy, we develop a new surface density model of the birth location of neutron stars. We explore models of neutron star evolution with magnetic field-decay, and with different initial period and magnetic field distributions. We present preliminary results including simulated population statistics that are compared with recent detections by Fermi of normal, isolated pulsars.

Gonthier, Peter L; Harding, Alice K; Grenier, Isabelle A; Pierbattista, Marco

2011-01-01T23:59:59.000Z

292

Combinatorial density functional theory-based screening of surface alloys for the oxygen reduction reaction.  

DOE Green Energy (OSTI)

A density functional theory (DFT) -based, combinatorial search for improved oxygen reduction reaction (ORR) catalysts is presented. A descriptor-based approach to estimate the ORR activity of binary surface alloys, wherein alloying occurs only in the surface layer, is described, and rigorous, potential-dependent computational tests of the stability of these alloys in aqueous, acidic environments are presented. These activity and stability criteria are applied to a database of DFT calculations on nearly 750 binary transition metal surface alloys; of these, many are predicted to be active for the ORR but, with few exceptions, they are found to be thermodynamically unstable in the acidic environments typical of low-temperature fuel cells. The results suggest that, absent other thermodynamic or kinetic mechanisms to stabilize the alloys, surface alloys are unlikely to serve as useful ORR catalysts over extended periods of operation.

Greeley, J.; Norskov, J.; Center for Nanoscale Materials; Technical Univ. of Denmark

2009-03-26T23:59:59.000Z

293

Study of the influence of a strong magnetic field on the composition of nuclear matter at high densities and zero temperature  

Science Conference Proceedings (OSTI)

Magnetars are neutron stars with a strong surface magnetic field. Observations of soft gamma-ray and anomalous X-ray pulsars pointed out that the surface magnetic field of magnetars is equal or even greater than 10{sup 15} G. In this work we study the influence of a strong magnetic field on the composition of nuclear matter at high densities and zero temperature. We describe the matter through a relativistic mean-field model with eight light baryons (baryon octet), electrons, muons and with magnetic field. As output of the numerical calculations, we obtain the relative population of each species of particles as function of baryon density.

Coelho, Eduardo L.; Chiapparini, Marcelo [Instituto de Fisica, Universidade do Estado do Rio de Janeiro, 20559-900, Rio de Janeiro, RJ (Brazil); Bracco, Mirian E. [Faculdade de Tecnologia, Universidade do Estado do Rio de Janeiro, 27537-000, Resende, RJ (Brazil)

2013-03-25T23:59:59.000Z

294

Vortex creep and critical current densities in superconducting (Ba,K)Fe2As2 single crystals  

Science Conference Proceedings (OSTI)

The surprisingly rapid relaxation of the sustainable current density in the critical state of single-crystalline Ba1?xKxFe2As2 is investigated for magnetic fields oriented parallel to the c axis and to the ab plane, respectively. Due to the inadequacy of standard analysis procedures developed for flux creep in the high-temperature superconducting cuprates, we develop a simple, straightforward data treatment technique that reveals the creep mechanism and the creep exponent ?. At low magnetic fields, below the second magnetization peak, ? varies only slightly as a function of temperature and magnetic flux density B. From the data, we determine the temperature and field dependencies of the effective activation barrier for creep. At low temperatures, the measured current density approaches the zero-temperature critical current density (in the absence of creep) to within a factor 2, thus lending credence to earlier conclusions drawn with respect to the pinning mechanism. The comparable values of the experimental screening current density and the zero-temperature critical current density reveal the limited usefulness of the widely used “interpolation formula.”

Konczykowski, M.; van Der Beek, C.J.; Tanatar, Makariy A.; Luo, Huiqian; Wang, Zhaosheng; Shen, Bing; Wen, Hai Hu; Prozorov, Ruslan

2012-07-13T23:59:59.000Z

295

Use of density equalizing map projections (DEMP) in the analysis of childhood cancer in four California counties  

SciTech Connect

In studying geographic disease distributions, one normally compares rates of arbitrarily defined geographic subareas (e.g. census tracts), thereby sacrificing 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). 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 rates are constant. The density equalized map portrays both individual cases and rates, and can be understood by untrained observers. Simple statistical techniques can be used to test the uniformity of the transformed map. This report describes application of the DEMP technique to a sizeable `real-world` data set: 401 childhood cancer cases occurring between 1980 and 1988 in four California counties. In an earlier analysis of the same data, the California Department of Health Services (DHS) calculated rates for 101 communities and found no significant geographic variability. The DDS 1980--88 population estimates are no longer available, so in this analysis 1980 Census data were used; geographic units were 262 census tracts. A k`th nearest neighbor analysis, corrected for boundary effects and for within-tract variability, provides strong evidence for geographic nonuniformity in tract rates ({rho} < l0{sup {minus}4}). No such effect is observed for artificial cases generated under the assumption of constant rates. Pending reanalysis with 1980-88 population estimates, no epidemiologic conclusions can be drawn at this time.

Merrill, D.W. Selvin, S.; Close, E.R.; Holmes, H.H.

1995-04-01T23:59:59.000Z

296

Population Status and Evaluation of Landscape Change for the Lower Keys Marsh Rabbit  

E-Print Network (OSTI)

Wildlife biologists and land managers tasked with the recovery of the endangered Lower Keys marsh rabbit (LKMR; Sylvilagus palustris hefneri) were in need of a current population estimate as well as a method to estimate the LKMR population annually. Habitat loss and fragmentation from population growth and development have threatened the existence of the LKMR. Establishing and understanding long-term habitat availability for the LKMR is important for determining causes of historical population declines as well as designing and implementing successful recovery plans. I conducted a range-wide pellet survey and a mark-recapture study to estimate the LKMR population. I evaluated the fit of 5 models and considered the variation in behavioral response model the best model. I correlated (r2 = 0.913) this model's rabbit abundance estimates to pellet density in 11 patches and generated a range-wide population estimate of 317, a western clade population of 257, an eastern clade population of 25, and translocated LKMR populations of 35 and 0 on Little Pine and Water keys, respectively. This prediction equation provides managers a quick, efficient, and non-invasive method to estimate LKMR abundance from pellet counts. To quantify the amount of habitat loss and fragmentation that occurred over the last 50 years, I systematically delineated and compared potential LKMR habitat using 1959 and 2006 aerial photographs. Additionally, I investigated if other factors could have reduced the amount of suitable habitat available for the LKMR with a comparison of habitat loss and fragmentation on a developed island and an undeveloped island. Range-wide, I found that number of habitat patches increased by 38, total class area decreased by 49.0%, and mean patch size decreased by 44.3%. Mean shape index increased by 4.2% and mean proximity index decreased by 13%. Both the 1959 and 2006 connectance indices were low while the 2006 set decreased 12.1%. I observed the same patterns of habitat loss and fragmentation on both the developed and undeveloped islands as I did in the range-wide landscape analysis. I found that LKMR habitat has declined in area and become more fragmented over the last 50 years. Habitat loss and fragmentation by development have directly endangered the LKMR; however, sea level rise and woody encroachment also could have historically caused habitat loss and fragmentation. Although development in LKMR habitat was halted, sea-level rise and woody encroachment could continue to alter LKMR habitat.

Schmidt, Jason Alan

2009-12-01T23:59:59.000Z

297

Soil Density/Moisture Gauge | Department of Energy  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Soil Density/Moisture Gauge Soil Density/Moisture Gauge Soil Density/Moisture Gauge This scenario provides the planning instructions, guidance, and evaluation forms necessary to conduct an exercise involving a highway shipment of a soil moisture/density gauge (Class 7 - Radioactive). This exercise manual is one in a series of five scenarios developed by the Department of Energy Transportation Emergency Preparedness Program (TEPP). Responding agencies may include several or more of the following: local municipal and county fire, police, sheriff and Emergency Medical Services (EMS) personnel; state, local, and federal emergency response teams; emergency response contractors; and other emergency response resources that could potentially be provided by the carrier and the originating facility (shipper).

298

Viscosity and density tables of sodium chloride solutions  

DOE Green Energy (OSTI)

A file is presented containing tabulated data extracted from the scientific literature on the density and viscosity of aqueous sodium chloride solutions. Also included is a bibliography of the properties of aqueous sodium chloride solutions. (MHR)

Fair, J.A.; Ozbek, H. (comps.) [comps.

1977-04-01T23:59:59.000Z

299

Synoptic Flow and Density Observations near an Arctic Shelf Break  

Science Conference Proceedings (OSTI)

Analyses of data from three shipborne surveys describe the quasi-synoptic density and velocity fields near Barrow Canyon, Alaska. The canyon parallels the northwestern coast of Alaska and contains three different water masses. These are 1) warm ...

Andreas Münchow; Eddy C. Carmack

1997-07-01T23:59:59.000Z

300

State of the art in photon density estimation  

Science Conference Proceedings (OSTI)

Photon-density estimation techniques are a popular choice for simulating light transport in scenes with complicated geometry and materials. This class of algorithms can be used to accurately simulate inter-reflections, caustics, color bleeding, scattering ...

Toshiya Hachisuka; Wojciech Jarosz; Guillaume Bouchard; Per Christensen; Jeppe Revall Frisvad; Wenzel Jakob; Henrik Wann Jensen; Michael Kaschalk; Claude Knaus; Andrew Selle; Ben Spencer

2012-08-01T23:59:59.000Z

Note: This page contains sample records for the topic "activity population density" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


301

Magnetic Method to Characterize the Current Densities in Breaker Arc  

Science Conference Proceedings (OSTI)

The purpose of this research was to use magnetic induction measurements from a low voltage breaker arc, to reconstruct the arc's current density. The measurements were made using Hall effect sensors, which were placed close to, but outside the breaking device. The arc was modelled as a rectangular current sheet, composed of a mix of threadlike current segments and with a current density varying across the propagation direction. We found the magnetic induction of the arc is a convolution product of the current density, and a function depending on the breaker geometry and arc model. Using deconvolution methods, the current density in the electric arc was determined.The method is used to study the arc behavior into the breaker device. Notably, position, arc size, and electric conductivity could all be determined, and then used to characterize the arc mode, diffuse or concentrated, and study the condition of its mode changing.

Machkour, Nadia [National Institute of Standards and Technology (United States)

2005-04-15T23:59:59.000Z

302

Diagnosing Mesoscale Vertical Motion from Horizontal Velocity and Density Data  

Science Conference Proceedings (OSTI)

The mesoscale vertical velocity is obtained by solving a generalized omega equation (? equation) using density and horizontal velocity data from three consecutive quasi-synoptic high-resolution surveys in the Alboran Sea. The Atlantic Jet (AJ) ...

Enric Pallàs Sanz; Álvaro Viúdez

2005-10-01T23:59:59.000Z

303

Nonextensive theory of dark matter and gas density profiles  

E-Print Network (OSTI)

Pronounced core-halo patterns of dark matter and gas density profiles, observed in relaxed galaxies and clusters, were hitherto fitted by empirical power-laws. On the other hand, similar features are well known from astrophysical plasma environments, subject to long-range interactions, modeled in the context of nonextensive entropy generalization. We link nonextensive statistics to the problem of density distributions in large-scale structures and provide fundamentally derived density profiles, representing accurately the characteristics of both, dark matter and hot plasma distributions, as observed or generated in simulations. The bifurcation of the density distribution into a kinetic dark matter and thermodynamic gas branch turns out as natural consequence of the theory and is controlled by a single parameter kappa, measuring physically the degree of coupling within the system. Consequently, it is proposed to favor nonextensive distributions, derived from the fundamental physical context of entropy generali...

Leubner, M P

2005-01-01T23:59:59.000Z

304

Diffusion driven object propulsion in density stratified fluids  

E-Print Network (OSTI)

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 ...

Lenahan, Conor (Conor P.)

2009-01-01T23:59:59.000Z

305

A Neutral Density Variable for the World’s Oceans  

Science Conference Proceedings (OSTI)

The use of density surfaces in the analysis of oceanographic data and in models of the ocean circulation is widespread. The present best method of fitting these isopycnal surfaces to hydrographic data is based on a linked sequence of potential ...

David R. Jackett; Trevor J. McDougall

1997-02-01T23:59:59.000Z

306

Metastable states of hydrogen: their geometric phases and flux densities  

E-Print Network (OSTI)

We discuss the geometric phases and flux densities for the metastable states of hydrogen with principal quantum number n=2 being subjected to adiabatically varying external electric and magnetic fields. Convenient representations of the flux densities as complex integrals are derived. Both, parity conserving (PC) and parity violating (PV) flux densities and phases are identified. General expressions for the flux densities following from rotational invariance are derived. Specific cases of external fields are discussed. In a pure magnetic field the phases are given by the geometry of the path in magnetic field space. But for electric fields in presence of a constant magnetic field and for electric plus magnetic fields the geometric phases carry information on the atomic parameters, in particular, on the PV atomic interaction. We show that for our metastable states also the decay rates can be influenced by the geometric phases and we give a concrete example for this effect. Finally we emphasise that the general...

Gasenzer, T; Trappe, M -I

2011-01-01T23:59:59.000Z

307

Production and Handling Slide 33: Density of UF6  

NLE Websites -- All DOE Office Websites (Extended Search)

of UF6 Skip Presentation Navigation First Slide Previous Slide Next Slide Last Presentation Table of Contents Density of UF6 Refer to caption below for image description The...

308

An evolutionary fuel assembly design for high power density BWRs  

E-Print Network (OSTI)

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 ...

Karahan, Aydin

2007-01-01T23:59:59.000Z

309

The design of high power density annular fuel for LWRs  

E-Print Network (OSTI)

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 ...

Yuan, Yi, 1975-

2004-01-01T23:59:59.000Z

310

The Circulation Dynamics and Thermodynamics of Upper Ocean Density Fronts  

Science Conference Proceedings (OSTI)

This paper extends a previous hydrodynamic circulation model of established, persistent upper ocean density fronts by including a thermodynamic or buoyancy equation in the integral treatment. An analysis is also conducted of the variables related ...

Richard W. Garvine

1980-12-01T23:59:59.000Z

311

Density-permittivity relationships for powdered and granular materials  

SciTech Connect

Relationships between the permittivities of powdered or granular solid materials and their bulk densities (density of the air-particle mixture) are discussed. Linear relationships between functions of the permittivity and bulk density are identified that are useful in determining permittivity of solids from measurements of the permittivity of pulverized samples. The usefulness of several dielectric mixture equations for calculating solid material permittivity from measured permittivity of pulverized samples is also discussed. Results of testing linear extrapolation techniques and dielectric mixture equations on pulverized coal, limestone, plastics, and granular wheat and flour are presented. Recommendations are provided for reliable estimation of solid material permittivities or changes in permittivities of powdered and granular materials as a result of changes in their bulk densities.

Nelson, S.O. [USDA ARS, Athens, GA (United States). Russell Research Center

2005-10-01T23:59:59.000Z

312

Fragment-based Time-dependent Density-functional Theory  

E-Print Network (OSTI)

Using the Runge-Gross theorem that establishes the foundation of Time-dependent Density Functional Theory (TDDFT) we prove that for a given electronic Hamiltonian, choice of initial state, and choice of fragmentation, there is a unique single-particle potential (dubbed time-dependent partition potential) which, when added to each of the pre-selected fragment potentials, forces the fragment densities to evolve in such a way that their sum equals the exact molecular density at all times. This uniqueness theorem suggests new ways of computing time-dependent properties of electronic systems via fragment-TDDFT calculations. We derive a formally exact relationship between the partition potential and the total density, and illustrate our approach on a simple model system for binary fragmentation in a laser field.

Mosquera, Martin A; Wasserman, Adam

2013-01-01T23:59:59.000Z

313

Observations of Seven Atmospheric Density Current Fronts in Dixon, California  

Science Conference Proceedings (OSTI)

Seven atmospheric density current fronts are identified in sequences of ground-based, scanning aerosol backscatter lidar images and in situ micrometeorological time series data that were collected simultaneously and nearly continuously between 15 ...

Shane D. Mayor

2011-05-01T23:59:59.000Z

314

Low density lipoprotein fraction assay for cardiac disease risk  

DOE Patents (OSTI)

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.

Krauss, Ronald M. (Berkeley, CA); Blanche, Patricia J. (Berkeley, CA); Orr, Joseph (San Pablo, CA)

1999-01-01T23:59:59.000Z

315

Dynamical density functional theory for dense atomic liquids  

E-Print Network (OSTI)

Starting from Newton's equations of motion, we derive a dynamical density functional theory (DDFT) applicable to atomic liquids. The theory has the feature that it requires as input the Helmholtz free energy functional from equilibrium density functional theory. This means that, given a reliable equilibrium free energy functional, the correct equilibrium fluid density profile is guaranteed. We show that when the isothermal compressibility is small, the DDFT generates the correct value for the speed of sound in a dense liquid. We also interpret the theory as a dynamical equation for a coarse grained fluid density and show that the theory can be used (making further approximations) to derive the standard mode coupling theory that is used to describe the glass transition. The present theory should provide a useful starting point for describing the dynamics of inhomogeneous atomic fluids.

A. J. Archer

2006-04-25T23:59:59.000Z

316

Asymmetric Tidal Mixing due to the Horizontal Density Gradient  

Science Conference Proceedings (OSTI)

Stratification and turbulent mixing exhibit a flood–ebb tidal asymmetry in estuaries and continental shelf regions affected by horizontal density gradients. The authors use a large-eddy simulation (LES) model to investigate the penetration of a ...

Ming Li; John Trowbridge; Rocky Geyer

2008-02-01T23:59:59.000Z

317

Effect of Lithium PFC Coatings on NSTX Density Control  

Science Conference Proceedings (OSTI)

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.

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

318

Magnetic Fields in High-Density Stellar Matter  

E-Print Network (OSTI)

I briefly review some aspects of the effect of magnetic fields in the high density regime relevant to neutron stars, focusing mainly on compact star structure and composition, superconductivity, combustion processes, and gamma ray bursts.

German Lugones

2005-04-20T23:59:59.000Z

319

Mutual Intrusion of a Gravity Current and Density Front Formation  

Science Conference Proceedings (OSTI)

A two-dimensional prognostic model was employed to examine the mutual intrusion of a gravity current and the formation of a density front. The results indicated strong vertical motion near the front and, with Earth rotation included, a baroclinic ...

Dono-Ping Wang

1984-07-01T23:59:59.000Z

320

Distribution of Radiation Density in a Homogeneous Cloudy Laye  

NLE Websites -- All DOE Office Websites (Extended Search)

of Radiation Density in a Homogeneous Cloudy Layer S. V. Dvoryashin, K. A. Shukorov, A. H. Shukurov, and G. S. Golitsyn A. M. Obukhov Institute of Atmospheric Physics Russian...

Note: This page contains sample records for the topic "activity population density" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


321

Reduced-Memory Decoding of Low-Density Lattice Codes  

E-Print Network (OSTI)

This letter describes a belief-propagation decoder for low-density lattice codes of finite dimension, in which the messages are represented as single Gaussian functions. Compared to previously-proposed decoders, memory is ...

Kurkoski, Brian

322

High-density Fuel Development for High Performance Research ...  

Science Conference Proceedings (OSTI)

Abstract Scope, High density UMo (7-12wt% Mo) fuel for high performance research ... High Energy X-ray Diffraction Study of Deformation Behavior of Alloy HT9.

323

Low density lipoprotein fraction assay for cardiac disease risk  

DOE Patents (OSTI)

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.

Krauss, R.M.; Blanche, P.J.; Orr, J.

1999-07-20T23:59:59.000Z

324

Does Cosmological Vacuum Energy Density have an Electric Reason ?  

E-Print Network (OSTI)

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.

Claus W. Turtur

2004-03-11T23:59:59.000Z

325

Effects of Lubrication on Density Gradient of Titanium Powder ...  

Science Conference Proceedings (OSTI)

It was found that 0.3wt% of lubricant significantly improves the density variation, but ... of Ti-6Al-4V Components Made by Electron Beam Additive Manufacturing.

326

Turbulence Patch Identification in Potential Density or Temperature Profiles  

Science Conference Proceedings (OSTI)

The Thorpe analysis is a recognized method used to identify and characterize turbulent regions within stably stratified fluids. By comparing an observed profile of potential temperature or potential density to a reference profile obtained by ...

Richard Wilson; Hubert Luce; Francis Dalaudier; Jacques Lefrère

2010-06-01T23:59:59.000Z

327

Estimating Geometric Dislocation Densities in Polycrystalline Materialsfrom Orientation Imaging Microscopy  

Science Conference Proceedings (OSTI)

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.

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

328

Paper area density measurement from forward transmitted scattered light  

DOE Patents (OSTI)

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.

Koo, Jackson C. (San Ramon, CA)

2001-01-01T23:59:59.000Z

329

Mixed Layer Restratification Due to a Horizontal Density Gradient  

Science Conference Proceedings (OSTI)

The restratification in the surface mixed layer driven by a horizontal density gradient following a storm is examined. For a constant layer depth H and constant buoyancy gradient |bx| = M2, geostrophic adjustment leads to new stratification with ...

Amit Tandon; Chris Garrett

1994-06-01T23:59:59.000Z

330

Simulations of liquid ribidium expanded to the critical density  

Science Conference Proceedings (OSTI)

Quantum molecular dynamic simulations were used to examine the change in atomic and electronic structure in liquid rubidium along its liquid-vapor coexistence curve. Starting from the liquid at the triple point, with increasing expansion we observe a continuous increase in the electron localization leading to ion clustering near the metal-nonmetal transition at about twice the critical density, in agreement with electrical measurements, and to the presence of dimers near and below the critical density.

Ross, M; Yang, L H; Pilgrim, W

2006-05-16T23:59:59.000Z

331

Density dependence of symmetry free energy of hot nuclei  

E-Print Network (OSTI)

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.

S. K. Samaddar; J. N. De; X. Vinas; M. Centelles

2008-04-15T23:59:59.000Z

332

Non-invasive fluid density and viscosity measurement  

SciTech Connect

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.

Sinha, Dipen N. (Los Alamos, NM)

2012-05-01T23:59:59.000Z

333

The density of surface states as the total time delay  

E-Print Network (OSTI)

For a scattering problem of tight-binding Bloch electrons by a weak random surface potential, a generalized Levinson theorem is put forward showing the equality of the total density of surface states and the density of the total time delay. The proof uses explicit formulas for the wave operators in the new rescaled energy and interaction (REI) representation, as well as an index theorem for adequate associated operator algebras.

Hermann Schulz-Baldes

2013-05-09T23:59:59.000Z

334

Density Functional Theory with Dissipation: Transport through Single Molecules  

SciTech Connect

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.

Kieron Burke

2012-04-30T23:59:59.000Z

335

The benchmark of gutzwiller density functional theory in hydrogen systems  

SciTech Connect

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.

Yao, Y.; Wang, Cai-Zhuang; Ho, Kai-Ming

2012-02-23T23:59:59.000Z

336

Observation of low magnetic field density peaks in helicon plasma  

SciTech Connect

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.

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

337

Neutron skin uncertainties of Skyrme energy density functionals  

E-Print Network (OSTI)

Background: Neutron-skin thickness is an excellent indicator of isovector properties of atomic nuclei. As such, it correlates strongly with observables in finite nuclei that depend on neutron-to-proton imbalance and the nuclear symmetry energy that characterizes the equation of state of neutron-rich matter. A rich worldwide experimental program involving studies with rare isotopes, parity violating electron scattering, and astronomical observations is devoted to pinning down the isovector sector of nuclear models. Purpose: We assess the theoretical systematic and statistical uncertainties of neutron-skin thickness and relate them to the equation of state of nuclear matter, and in particular to nuclear symmetry energy parameters. Methods: We use the nuclear superfluid Density Functional Theory with several Skyrme energy density functionals and density dependent pairing. To evaluate statistical errors and their budget, we employ the statistical covariance technique. Results: We find that the errors on neutron skin increase with neutron excess. Statistical errors due to uncertain coupling constants of the density functional are found to be larger than systematic errors, the latter not exceeding 0.06 fm in most neutron-rich nuclei across the nuclear landscape. The single major source of uncertainty is the poorly determined slope L of the symmetry energy that parametrizes its density dependence. Conclusions: To provide essential constraints on the symmetry energy of the nuclear energy density functional, next-generation measurements of neutron skins are required to deliver precision better than 0.06 fm.

M. Kortelainen; J. Erler; W. Nazarewicz; N. Birge; Y. Gao; E. Olsen

2013-07-16T23:59:59.000Z

338

Atomic hydrogen density measurements in the Tara tandem mirror experiment  

DOE Green Energy (OSTI)

Neutral and plasma density have been measured in the north well of the central cell of the Tara tandem mirror (Nucl. Fusion {bold 22}, 549 (1982)). The electron plasma density and temperature on the magnetic axis were measured by Thomson scattering to be about 3{times}10{sup 12} cm{sup {minus}3} and 70 eV, respectively. The corresponding axial neutral hydrogen density was found to be 1 {times}10{sup 9} cm{sup {minus}3}, while near the plasma edge at {ital r}=15 cm it reached 1{times}10{sup 10} cm{sup {minus}3}. The fill gas density at {ital r}{ge}22.5 cm was {approx}10{sup 11} cm{sup {minus}3}. Additional information from secondary electron detectors was used to estimate the radial ion temperature distribution, which was found to have about the same width, 12 cm, as the plasma density. The resulting ion pressure profile is peaked compared to the electron pressure profile. Charge exchange losses in the well are found to have a maximum at a radius equal to half the {ital e}-folding distance of the plasma density and ion temperature distributions.

Guss, W.C.; Yao, X.Z.; Pocs, L.; Mahon, R.; Casey, J.; Horne, S.; Lane, B.; Post, R.S.; Torti, R.P. (Plasma Fusion Center, Massachusetts Institute of Technology, Cambridge, MA (USA))

1990-09-01T23:59:59.000Z

339

Densities and energies of nuclei in dilute matter  

E-Print Network (OSTI)

We explore the ground-state properties of nuclear clusters embedded in a gas of nucleons with the help of Skyrme-Hartree-Fock microscopic calculations. Two alternative representations of clusters are introduced, namely coordinate-space and energy-space clusters. We parameterize their density profiles in spherical symmetry in terms of basic properties of the energy density functionals used and propose an analytical, Woods-Saxon density profile whose parameters depend, not only on the composition of the cluster, but also of the nucleon gas. We study the clusters' energies with the help of the local-density approximation, validated through our microscopic results. We find that the volume energies of coordinate-space clusters are determined by the saturation properties of matter, while the surface energies are strongly affected by the presence of the gas. We conclude that both the density profiles and the cluster energies are strongly affected by the gas and discuss implications for the nuclear EoS and related perspectives. Our study provides a simple, but microscopically motivated modeling of the energetics of clusterized matter at subsaturation densities, for direct use in consequential applications of astrophysical interest.

P. Papakonstantinou; J. Margueron; F. Gulminelli; Ad. R. Raduta

2013-05-01T23:59:59.000Z

340

Nuclear Density Functional Theory and the Equation of State  

E-Print Network (OSTI)

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.

Yeunhwan Lim

2011-04-06T23:59:59.000Z

Note: This page contains sample records for the topic "activity population density" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


341

Nuclear Density Functional Theory and the Equation of State  

E-Print Network (OSTI)

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.

Lim, Yeunhwan

2011-01-01T23:59:59.000Z

342

Measuring and Modeling Fault Density for Plume-Fault Encounter Probability Estimation  

Science Conference Proceedings (OSTI)

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.

Jordan, P.D.; Oldenburg, C.M.; Nicot, J.-P.

2011-05-15T23:59:59.000Z

343

Examining the specific entropy (density of adiabatic invariants) of the outer electron radiation belt  

Science Conference Proceedings (OSTI)

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%.

Borovsky, Joseph E [Los Alamos National Laboratory; Denton, Michael H [LANCASTER UNIV

2008-01-01T23:59:59.000Z

344

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

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

WASHINGTON WASHINGTON February 11, 1994 MEMORANDUM FOR THE HEADS OF ALL DEPARTMENTS AND AGENCIES SUBJECT: Executive Order on Federal Actions to Address Environmental Justice in Minority Populations and Low- Income Populations Today I have issued an Executive Order on Federal Actions to Address Environmental Justice in Minority Populations and Low-Income Populations. That order is designed to focus Federal attention on the environmental and human health conditions in minority communities and low-income communities with the goal of achieving environmental justice. That order is also intended to promote nondiscrimination in Federal programs substantially affecting human health and the environment, and to provide minority communities and low-income communities access to public

345

Bacterial Population Genetics in a Forensic Context  

SciTech Connect

This report addresses the recent Department of Homeland Security (DHS) call for a Phase I study to (1) assess gaps in the forensically relevant knowledge about the population genetics of eight bacterial agents of concern, (2) formulate a technical roadmap to address those gaps, and (3) identify new bioinformatics tools that would be necessary to analyze and interpret population genetic data in a forensic context. The eight organisms that were studied are B. anthracis, Y. pestis, F. tularensis, Brucella spp., E. coli O157/H7, Burkholderia mallei, Burkholderia pseudomallei, and C. botulinum. Our study focused on the use of bacterial population genetics by forensic investigators to test hypotheses about the possible provenance of an agent that was used in a crime or act of terrorism. Just as human population genetics underpins the calculations of match probabilities for human DNA evidence, bacterial population genetics determines the level of support that microbial DNA evidence provides for or against certain well-defined hypotheses about the origins of an infecting strain. Our key findings are: (1) Bacterial population genetics is critical for answering certain types of questions in a probabilistic manner, akin (but not identical) to 'match probabilities' in DNA forensics. (2) A basic theoretical framework for calculating likelihood ratios or posterior probabilities for forensic hypotheses based on microbial genetic comparisons has been formulated. This 'inference-on-networks' framework has deep but simple connections to the population genetics of mtDNA and Y-STRs in human DNA forensics. (3) The 'phylogeographic' approach to identifying microbial sources is not an adequate basis for understanding bacterial population genetics in a forensic context, and has limited utility, even for generating 'leads' with respect to strain origin. (4) A collection of genotyped isolates obtained opportunistically from international locations augmented by phylogenetic representations of relatedness will not and enzootic outbreaks noted through international outbreak surveillance systems, and 'representative' genetic sequences from each outbreak. (5) Interpretation of genetic comparisons between an attack strain and reference strains requires a model for the network structure of maintenance foci, enzootic outbreaks, and human outbreaks of that disease, coupled with estimates of mutational rate constants. Validation of the model requires a set of sequences from exemplary outbreaks and laboratory data on mutation rates during animal passage. The necessary number of isolates in each validation set is determined by disease transmission network theory, and is based on the 'network diameter' of the outbreak. (6) The 8 bacteria in this study can be classified into 4 categories based on the complexity of the transmission network structure of their natural maintenance foci and their outbreaks, both enzootic and zoonotic. (7) For B. anthracis, Y. pestis, E. coli O157, and Brucella melitensis, and their primary natural animal hosts, most of the fundamental parameters needed for modeling genetic change within natural host or human transmission networks have been determined or can be estimated from existing field and laboratory studies. (8) For Burkholderia mallei, plausible approaches to transmission network models exist, but much of the fundamental parameterization does not. In addition, a validated high-resolution typing system for characterizing genetic change within outbreaks or foci has not yet been demonstrated, although a candidate system exists. (9) For Francisella tularensis, the increased complexity of the transmission network and unresolved questions about maintenance and transmission suggest that it will be more complex and difficult to develop useful models based on currently available data. (10) For Burkholderia pseudomallei and Clostridium botulinum, the transmission and maintenance networks involve complex soil communities and metapopulations about which very little is known. It is not clear that these pathogens can be brought into the in

Velsko, S P

2009-11-02T23:59:59.000Z

346

Chemical Activation  

NLE Websites -- All DOE Office Websites (Extended Search)

Chemical Activation of Single-walled Carbon Nanotubes for Hydrogen Adsorption Milton R. Smith, Jr., 1 Edward W. Bittner, 1 Wei Shi, 1, 2 J. Karl Johnson, 1, 2 and Bradley C....

347

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

E-Print Network (OSTI)

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 of environmental pollutants within aquatic environments. Pollutants such as endocrine disruptors and heavy metals have the potential to impact both human and wildlife populations in contaminated areas. While much research has focused on how these compounds impact natural selection processes, such as viability and reproduction, their effect on sexual selection processes is not as clear. The goal of this dissertation was to address how environmental contaminants impact sexual selection processes in a sex-role reversed pipefish and evaluate how these effects may impact long-term population viability. Here we show that short periods of exposure to environmentally relevant concentrations of a synthetic estrogen result in male pipefish with female-like secondary sexual traits. While these males are capable of reproduction, exposed males are discriminated against by females in mate choice tests. In natural populations, this type of discrimination could reduce male mating opportunities, potentially reducing their reproductive success. In an additional component of this dissertation, it was discovered that pipefish populations around Mobile Bay, specifically Weeks Bay, are currently being exposed to significantly elevated levels of mercury. These populations are genetically distinct from coastal populations but moderate levels of gene flow occur among sites, and gene flow between contaminated and non-contaminated population may be influencing how environmental contaminants are impacting genetic diversity and population viability. In the case of endocrine disruptors, migration between contaminated and non-contaminated sites may negatively impact population viability. Morphological traits induced with exposure to contaminants may be maintained for extended periods of time, therefore, the effect the exposed phenotype has on mating dynamics and sexual selection could be carried to non-contaminated sites if exposed individuals move to new populations. On the other hand, immigration of individuals from non-contaminated sites into contaminated areas may help maintain genetic diversity within exposed populations. In conclusion, the work presented in this dissertation shows that the presence of environmental toxins can significantly impact sexual selection processes, which in turn can have profound effects on the viability and future evolutionary trajectory of populations. Future work in this area should not only address how these toxins impact individual fitness, but should also address how population structure may be influencing the severity of these compounds on natural populations.

Partridge, Charlyn G.

2009-12-01T23:59:59.000Z

348

Population Viability Analysis of Riverine Fishes  

DOE Green Energy (OSTI)

Many utilities face conflkts between two goals: cost-efficient hydropower generation and protecting riverine fishes. Research to develop ecological simulation tools that can evaluate alternative mitigation strategies in terms of their benefits to fish populations is vital to informed decision-making. In this paper, we describe our approach to population viability analysis of riverine fishes in general and Snake River white sturgeon in particular. We are finding that the individual-based modeling approach used in previous in-stream flow applications is well suited to addressing questions about the viability of species of concern for several reasons. Chief among these are: (1) the abiIity to represent the effects of individual variation in life history characteristics on predicted population viabili~, (2) the flexibili~ needed to quanti~ the ecological benefits of alternative flow management options by representing spatial and temporal variation in flow and temperaturty and (3) the flexibility needed to quantifi the ecological benefits of non-flow related manipulations (i.e., passage, screening and hatchery supplementation).

Bates, P.; Chandler, J.; Jager, H.I.; Lepla, K.; Van Winkle, W.

1999-04-12T23:59:59.000Z

349

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

Science Conference Proceedings (OSTI)

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)

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

2011-03-31T23:59:59.000Z

350

Direct Measurements of Pore Fluid Density by Vibrating Tube Densimetry  

Science Conference Proceedings (OSTI)

The densities of pore-confined fluids were measured for the first time by means of a vibrating tube method. Isotherms of total adsorption capacity were measured directly making the method complementary to the conventional gravimetric or volumetric/piezometric adsorption techniques, which yield the excess adsorption (the Gibbsian surface excess). A custom-made high-pressure, high-temperature vibrating tube densimeter (VTD) was used to measure the densities of subcritical and supercritical propane (between 35 C and 97 C) and supercritical carbon dioxide (between 32 C and 50 C) saturating hydrophobic silica aerogel (0.2 g/cm3, 90% porosity) synthesized inside Hastelloy U-tubes. Additionally, excess adsorption isotherms for supercritical CO2 and the same porous solid were measured gravimetrically using a precise magnetically-coupled microbalance. Pore fluid densities and total adsorption isotherms increased monotonically with increasing density of the bulk fluid, in contrast to excess adsorption isotherms, which reached a maximum at a subcritical density of the bulk fluid, and then decreased towards zero or negative values at supercritical densities. Compression of the confined fluid significantly beyond the density of the bulk liquid at the same temperature was observed at subcritical temperatures. The features of the isotherms of confined fluid density are interpreted to elucidate the observed behavior of excess adsorption. The maxima of excess adsorption were found to occur below the critical density of the bulk fluid at the conditions corresponding to the beginning of the plateau of total adsorption, marking the end of the transition of pore fluid to a denser, liquid-like pore phase. The results for propane and carbon dioxide showed similarity in the sense of the principle of corresponding states. No measurable effect of pore confinement on the liquid-vapor critical point was found. Quantitative agreement was obtained between excess adsorption isotherms determined from VTD total adsorption results and those measured gravimetrically at the same temperature, confirming the validity of the vibrating tube measurements. Vibrating tube densimetry was demonstrated as a novel experimental approach capable of providing the average density of pore-confined fluids.

Gruszkiewicz, Miroslaw {Mirek} S [ORNL; Rother, Gernot [ORNL; Wesolowski, David J [ORNL; Cole, David R [ORNL; Wallacher, Dirk [Helmholtz-Zentrum Berlin

2012-01-01T23:59:59.000Z

351

Excitation density distribution in electron-beam-pumped ZnSe semiconductor lasers  

Science Conference Proceedings (OSTI)

The spatial density distribution of the absorbed energy in ZnSe semiconductor lasers excited by electrons with energies from 2 keV to 1 MeV is calculated by the Monte-Carlo method. Approximate analytic expressions determining the absorbed energy of electrons in ZnSe are presented. The pump power threshold in a semiconductor quantum-well ZnSe structure is experimentally determined. The lasing threshold in such structures is estimated as a function of the electron energy. (active media)

Donskoi, E N; Zalyalov, A N; Petrushin, O N; Savel'ev, Yu A; Tarasov, M D; Shigaev, Yu S [Russian Federal Nuclear Center 'All-Russian Scientific Research Institute of Experimental Physics', Sarov, Nizhnii Novgorod Region (Russian Federation); Zhdanova, E V; Zverev, M M; Peregudov, D V [Moscow State Institute of Radio-Engineering, Electronics and Automation (Technical University), Moscow (Russian Federation); Ivanov, S V; Sedova, I V; Sorokin, S V [A.F. Ioffe Physico-Technical Institute, Russian Academy of Sciences, St. Petersburg (Russian Federation)

2008-12-31T23:59:59.000Z

352

Active Seismic Techniques | Open Energy Information  

Open Energy Info (EERE)

Active Seismic Techniques Active Seismic Techniques Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Technique: Active Seismic Techniques Details Activities (0) Areas (0) Regions (0) NEPA(0) Exploration Technique Information Exploration Group: Geophysical Techniques Exploration Sub Group: Seismic Techniques Parent Exploration Technique: Seismic Techniques Information Provided by Technique Lithology: Rock unit density influences elastic wave velocities. Stratigraphic/Structural: Structural geology- faults, folds, grabens, horst blocks, sedimentary layering, discontinuities, etc. Hydrological: Combining compressional and shear wave results can indicate the presence of fluid saturation in the formation. Thermal: High temperatures and pressure impact the compressional and shear wave velocities.

353

TA Orientation 2007 Activity 8 Designing a Problem Solving Framework/Answer Sheet  

E-Print Network (OSTI)

TA Orientation 2007 Activity 8 Designing a Problem Solving Framework/Answer Sheet Activity 8 - Page of population of students for whom they were developed. #12;TA Orientation 2007 Activity 8 Designing a Problem #12;TA Orientation 2007 Activity 8 Designing a Problem Solving Framework/Answer Sheet Activity 8

Minnesota, University of

354

TA Orientation 2006 Activity 8 Designing a Problem Solving Framework/Answer Sheet  

E-Print Network (OSTI)

TA Orientation 2006 Activity 8 Designing a Problem Solving Framework/Answer Sheet Activity 8 - Page of population of students for whom they were developed. #12;TA Orientation 2006 Activity 8 Designing a Problem #12;TA Orientation 2006 Activity 8 Designing a Problem Solving Framework/Answer Sheet Activity 8

Minnesota, University of

355

Relativistic Nuclear Energy Density Functionals: adjusting parameters to binding energies  

E-Print Network (OSTI)

We study a particular class of relativistic nuclear energy density functionals in which only nucleon degrees of freedom are explicitly used in the construction of effective interaction terms. Short-distance (high-momentum) correlations, as well as intermediate and long-range dynamics, are encoded in the medium (nucleon density) dependence of the strength functionals of an effective interaction Lagrangian. Guided by the density dependence of microscopic nucleon self-energies in nuclear matter, a phenomenological ansatz for the density-dependent coupling functionals is accurately determined in self-consistent mean-field calculations of binding energies of a large set of axially deformed nuclei. The relationship between the nuclear matter volume, surface and symmetry energies, and the corresponding predictions for nuclear masses is analyzed in detail. The resulting best-fit parametrization of the nuclear energy density functional is further tested in calculations of properties of spherical and deformed medium-heavy and heavy nuclei, including binding energies, charge radii, deformation parameters, neutron skin thickness, and excitation energies of giant multipole resonances.

T. Niksic; D. Vretenar; P. Ring

2008-09-08T23:59:59.000Z

356

Nonextensive theory of dark matter and gas density profiles  

E-Print Network (OSTI)

Pronounced core-halo patterns of dark matter and gas density profiles, observed in relaxed galaxies and clusters, were hitherto fitted by empirical power-laws. On the other hand, similar features are well known from astrophysical plasma environments, subject to long-range interactions, modeled in the context of nonextensive entropy generalization. We link nonextensive statistics to the problem of density distributions in large-scale structures and provide fundamentally derived density profiles, representing accurately the characteristics of both, dark matter and hot plasma distributions, as observed or generated in simulations. The bifurcation of the density distribution into a kinetic dark matter and thermodynamic gas branch turns out as natural consequence of the theory and is controlled by a single parameter kappa, measuring physically the degree of coupling within the system. Consequently, it is proposed to favor nonextensive distributions, derived from the fundamental physical context of entropy generalization and accounting for nonlocality and long-range interactions in gravitationally coupled systems, when modeling observed density profiles of astrophysical structures.

M. P. Leubner

2006-02-27T23:59:59.000Z

357

Role of ponderomotive density modification in IBW loading  

SciTech Connect

We solve numerically a second-order nonlinear ordinary differential equation [1] that describes EPW-IBW mode transformation at the lower-hybrid layer, including self-consistent ponderomotive density profile modification, for the electrostatic potential in front of the IBW antenna. The model is solved for the particular case of heating just below the second harmonic of the deuterium cyclotron frequency. Background density and temperature profiles are chosen to be appropriate for the IBW experiments on TFTR. We calculate the complex antenna impedance, assuming vacuum within the antenna box, and a local reflectivity which reveal diminished antenna loading with increasing ponderomotive pressure, compared to the linear prediction. The ponderomotive force steepens the density gradient in the edge plasma, thus enhancing reflection and lowering the loading resistance. The model also describes the direct launch of IBWs in high edge density regimes, lacking a lower-hybrid layer, where the impedance is found to be much smaller than in the low density regime. {copyright} {ital 1997 American Institute of Physics.}

Russell, D.A.; Myra, J.R.; DIppolito, D.A. [Lodestar Research Corp., 2400 Central Ave. P-5, Boulder, Colorado 80301 (United States)

1997-04-01T23:59:59.000Z

358

LONGITUDINAL OSCILLATIONS IN DENSITY STRATIFIED AND EXPANDING SOLAR WAVEGUIDES  

Science Conference Proceedings (OSTI)

Waves and oscillations can provide vital information about the internal structure of waveguides in which they propagate. Here, we analytically investigate the effects of density and magnetic stratification on linear longitudinal magnetohydrodynamic (MHD) waves. The focus of this paper is to study the eigenmodes of these oscillations. It is our specific aim to understand what happens to these MHD waves generated in flux tubes with non-constant (e.g., expanding or magnetic bottle) cross-sectional area and density variations. The governing equation of the longitudinal mode is derived and solved analytically and numerically. In particular, the limit of the thin flux tube approximation is examined. The general solution describing the slow longitudinal MHD waves in an expanding magnetic flux tube with constant density is found. Longitudinal MHD waves in density stratified loops with constant magnetic field are also analyzed. From analytical solutions, the frequency ratio of the first overtone and fundamental mode is investigated in stratified waveguides. For small expansion, a linear dependence between the frequency ratio and the expansion factor is found. From numerical calculations it was found that the frequency ratio strongly depends on the density profile chosen and, in general, the numerical results are in agreement with the analytical results. The relevance of these results for solar magneto-seismology is discussed.

Luna-Cardozo, M. [Instituto de Astronomia y Fisica del Espacio, CONICET-UBA, CC. 67, Suc. 28, 1428 Buenos Aires (Argentina); Verth, G. [School of Computing, Engineering and Information Sciences, Northumbria University, Newcastle Upon Tyne NE1 8ST (United Kingdom); Erdelyi, R., E-mail: mluna@iafe.uba.ar, E-mail: robertus@sheffield.ac.uk, E-mail: gary.verth@northumbria.ac.uk [Solar Physics and Space Plasma Research Centre (SP2RC), University of Sheffield, Hicks Building, Hounsfield Road, Sheffield S3 7RH (United Kingdom)

2012-04-01T23:59:59.000Z

359

Public Activities  

NLE Websites -- All DOE Office Websites (Extended Search)

publicactivities_header.jpg publicactivities_header.jpg Public Activities Citizens are encouraged to learn about the Department of Energy's programs through a variety of activities that are open to the public. Our goal is to educate citizens and seek their meaningful involvement. If you are visiting the area, the American Museum of Science and Energy in Oak Ridge is the best starting point for exhibits and information about DOE programs in science, environmental management, nuclear fuel supply, and national security. Tours are conducted of the Oak Ridge National Laboratory, Y-12 National Security Complex and East Tennessee Technology Park during the summer months departing from the Museum. For those with more specific interests in our programs, each month we publish a calendar of public involvement activities, which identifies announcements, comment periods and public meetings of potential interest. Our Environmental Management Program has a Site Specific Advisory Board composed of area citizens who meet the second Wednesday of each month.

360

ANL Activities  

NLE Websites -- All DOE Office Websites (Extended Search)

Activities of the DOD Activities of the DOD Project Office focus today on the Navy's Free Electron Laser Program Argonne Accelerator Institute Meeting June 16, 2009 2 Several Beam Activities and Interests Ongoing  Terahertz sources and applications  Navy Free Electron Laser (Focus area today)  Free Electron Laser Applications  Electromagnetic Interference Technology Review Committees  Novel Fiber Optic Materials with Army Research Lab  Optical Diagnostics for next-generation light sources  Neutron detection schemes  NATO Sensors and Electronics Panel, international field tests of directed energy source applications  Controls  Radiation Oncology 3 Background, Naval Directed Energy History The U.S Navy has been investigating utility of lasers since the 1960's and the

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361

Active curve axis Gaussian mixture models  

Science Conference Proceedings (OSTI)

Gaussian Mixture Models (GMM) have been broadly applied for the fitting of probability density function. However, due to the intrinsic linearity of GMM, usually many components are needed to appropriately fit the data distribution, when there are curve ... Keywords: AcaG, AcaGMM, Active curve axis, EM, Finite mixture models, GMM, Unsupervised learning

Baibo Zhang; Changshui Zhang; Xing Yi

2005-12-01T23:59:59.000Z

362

Evaluate Habitat Use and Population Dynamics of Lampreys in Cedar Creek, 2001 Annual Report.  

DOE Green Energy (OSTI)

Pacific lamprey (Lampetra tridentata) in the Columbia River Basin have declined to a remnant of their pre-1940s populations and the status of the western brook lamprey (L. richardsoni) is unknown. Identifying the biological and ecological factors limiting lamprey populations is critical to their recovery, but little research has been conducted on these species within the Columbia River Basin. This ongoing, multi-year study examines lamprey populations in Cedar Creek, Washington, a third-order tributary to the Lewis River. This annual report describes the activities and results of the second year of this project. Adult (n = 24), metamorphosed (n = 247), transforming (n = 4), and ammocoete (n = 387) stages from both species were examined in 2001. Lamprey were captured using adult fish ladders, lamprey pots, rotary screw traps, and lamprey electrofishers. Twenty-nine spawning ground surveys were conducted. Nine strategic point-specific habitat surveys were performed to assess habitat requirements of juvenile lamprey.

Stone, Jennifer; Pirtle, Jody; Barndt, Scott A.

2002-03-31T23:59:59.000Z

363

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

E-Print Network (OSTI)

Humans and horses weaved together wonderful stories of adventure and generosity. As a part of human history and civilization, Arabian horses ignite imagination throughout the world. Populations of this breed exist in many countries. Here I explored 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 of the breed. A third aim was to tackle the distribution pattern of the genetic variability within the genome to show whether there are differences in relative variability of different types of markers. First, I analyzed the genetic structure of 537Arabian horses from seven populations by using microsatellites. The results consistently showed higher levels of diversity within the Middle Eastern populations compared to the Western populations. All American-Arabians showed differentiation from Middle Eastern populations. Second, I sequenced the whole mtDNA D-loop of 251 Arabian horses. The whole D-loop sequence was more informative than using just the HVR1. Native populations from the Middle East, such as Syrian, represented a hot spot of genetic diversity. Most importantly, there was no evidence that the Arabian horse breed has clear subdivisions depending on the traditional maternal based strain classification system. Third, I tested the heterozygosity distribution pattern along the genome of 22 Peruvian Paso horses using 232 microsatellites and Single Nucleotide Polymorphisms (SNPs). The pattern of genetic diversity was completely different between these two markers where no correlation was found. Runs of homozygosity test of SNPs and associated microsatellites noticeably showed that all of associated microsatellites loci were homozygous in the matched case. The findings of this study will help in understanding the evolutionary history and developing breeding and conservation programs of horses. This study provided databases including parentage testing system and maternal lineages that will help to recover the Syrian Arabian population after the armed conflict started in Syria in 2011. The results here can be applied not only to horses, but also to other animal species with similar criteria.

Khanshour, Anas M

2013-08-01T23:59:59.000Z

364

High Energy Density Laboratory Plasmas Program | National Nuclear Security  

National Nuclear Security Administration (NNSA)

Program | National Nuclear Security Program | National Nuclear Security Administration Our Mission Managing the Stockpile Preventing Proliferation Powering the Nuclear Navy Emergency Response Recapitalizing Our Infrastructure Continuing Management Reform Countering Nuclear Terrorism About Us Our Programs Our History Who We Are Our Leadership Our Locations Budget Our Operations Media Room Congressional Testimony Fact Sheets Newsletters Press Releases Speeches Events Social Media Video Gallery Photo Gallery NNSA Archive Federal Employment Apply for Our Jobs Our Jobs Working at NNSA Blog High Energy Density Laboratory Plasmas Program Home > High Energy Density Laboratory Plasmas Program High Energy Density Laboratory Plasmas Program Steady advances in increasing the energy, power, and brightness of lasers and particle beams and advances in pulsed power systems have made possible

365

LANL | Physics | Inertial Confinement Fusion and High Energy Density  

NLE Websites -- All DOE Office Websites (Extended Search)

Inertial confinement and high density Inertial confinement and high density plasma physics Using the world's most powerful lasers, Physics Division scientists are aiming to create thermonuclear burn in the laboratory. The experimental research of the Physics Division's Inertial Confinement Fusion program is conducted at the National Ignition Facility at Lawrence Livermore National Laboratory, the OMEGA Laser Facility at the University of Rochester, and the Trident Laser Facility at Los Alamos. Within inertial confinement fusion and the high energy density area, Los Alamos specializes in hohlraum energetics, symmetry tuning, warm dense matter physics, and hydrodynamics in ultra-extreme conditions. When complete, this research will enable the exploitation of fusion as an energy resource and will enable advanced research in stockpile stewardship

366

Ducted kinetic Alfven waves in plasma with steep density gradients  

SciTech Connect

Given their high plasma density (n {approx} 10{sup 13} cm{sup -3}), it is theoretically possible to excite Alfven waves in a conventional, moderate length (L {approx} 2 m) helicon plasma source. However, helicon plasmas are decidedly inhomogeneous, having a steep radial density gradient, and typically have a significant background neutral pressure. The inhomogeneity introduces regions of kinetic and inertial Alfven wave propagation. Ion-neutral and electron-neutral collisions alter the Alfven wave dispersion characteristics. Here, we present the measurements of propagating kinetic Alfven waves in helium helicon plasma. The measured wave dispersion is well fit with a kinetic model that includes the effects of ion-neutral damping and that assumes the high density plasma core defines the radial extent of the wave propagation region. The measured wave amplitude versus plasma radius is consistent with the pile up of wave magnetic energy at the boundary between the kinetic and inertial regime regions.

Houshmandyar, Saeid [Solar Observatory Department, Prairie View A and M University, Prairie View, Texas 77446 (United States); Department of Physics, West Virginia University, Morgantown, West Virginia 26506-6315 (United States); Scime, Earl E. [Department of Physics, West Virginia University, Morgantown, West Virginia 26506-6315 (United States)

2011-11-15T23:59:59.000Z

367

Development of Novel Density Functionals for Thermochemical Kinetics  

E-Print Network (OSTI)

A new density functional theory (DFT) exchange-correlation functional for the exploration of reaction mechanisms is proposed. This new functional, denoted BMK (Boese-Martin for Kinetics), has an accuracy in the 2 kcal/mol range for transition state barriers but, unlike previous attempts at such a functional, this improved accuracy does not come at the expense of equilibrium properties. This makes it a general-purpose functional whose domain of applicability has been extended to transition states, rather than a specialized functional for kinetics. The improvement in BMK rests on the inclusion of the kinetic energy density together with a large value of the exact exchange mixing coefficient. For this functional, the kinetic energy density appears to correct `back' the excess exact exchange mixing for ground-state properties, possibly simulating variable exchange.

Boese, A D; Martin, Jan M. L.

2004-01-01T23:59:59.000Z

368

Density-based similarity measures for content based search  

Science Conference Proceedings (OSTI)

We consider the query by multiple example problem where the goal is to identify database samples whose content is similar to a coUection of query samples. To assess the similarity we use a relative content density which quantifies the relative concentration of the query distribution to the database distribution. If the database distribution is a mixture of the query distribution and a background distribution then it can be shown that database samples whose relative content density is greater than a particular threshold {rho} are more likely to have been generated by the query distribution than the background distribution. We describe an algorithm for predicting samples with relative content density greater than {rho} that is computationally efficient and possesses strong performance guarantees. We also show empirical results for applications in computer network monitoring and image segmentation.

Hush, Don R [Los Alamos National Laboratory; Porter, Reid B [Los Alamos National Laboratory; Ruggiero, Christy E [Los Alamos National Laboratory

2009-01-01T23:59:59.000Z

369

Stationary density profiles in the Alcator C-mod tokamak  

SciTech Connect

In the absence of an internal particle source, plasma turbulence will impose an intrinsic relationship between an inwards pinch and an outwards diffusion resulting in a stationary density profile. The Alcator C-mod tokamak utilizes RF heating and current drive so that fueling only occurs in the vicinity of the separatrix. Discharges that transition from L-mode to I-mode are seen to maintain a self-similar stationary density profile as measured by Thomson scattering. For discharges with negative magnetic shear, an observed rise of the safety factor in the vicinity of the magnetic axis appears to be accompanied by a decrease of electron density, qualitatively consistent with the theoretical expectations.

Kesner, J.; Ernst, D.; Hughes, J.; Mumgaard, R.; Shiraiwa, S.; Whyte, D. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Massachusetts 02139 (United States); Scott, S. [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08540 (United States)

2012-12-15T23:59:59.000Z

370

Low-density microcellular foam and method of making same  

DOE Patents (OSTI)

Low-density microcellular foam having a cell size of not greater than 2 .mu.m and method of making by dissolving cellulose acetate in an acetone-based solvent, gelling the solution in a water bath maintained at 0.degree.-10.degree. C for a selected period of time to allow impurities to diffuse out, freezing the gel, and then freeze-drying wherein water and solvents sublime and the gel structure solidifies into low-density microcellular foam. The foam has a density of 0.065 to 0.6.times.10.sup.3 kg/m.sup.3 and cell size of about 0.3 to 2 .mu.m. The small cell size foam is particularly applicable for encapsulation of laser targets.

Rinde, James A. (Livermore, CA)

1977-01-01T23:59:59.000Z

371

PREPARATION OF HIGH-DENSITY THORIUM OXIDE SPHERES  

DOE Patents (OSTI)

A method of preparing high-density thorium oxide spheres for use in pellet beds in nuclear reactors is presented. Sinterable thorium oxide is first converted to free-flowing granules by means such as compression into a compact and comminution of the compact. The granules are then compressed into cubes having a density of 5.0 to 5.3 grams per cubic centimeter. The cubes are tumbled to form spheres by attrition, and the spheres are then fired at 1250 to 1350 deg C. The fired spheres are then polished and fired at a temperature above 1650 deg C to obtain high density. Spherical pellets produced by this method are highly resistant to mechanical attrition hy water. (AEC)

McNees, R.A. Jr.; Taylor, A.J.

1963-12-31T23:59:59.000Z

372

Magnetohydrodynamics in Tokamak Reactors and its Effect on Plasma Density  

E-Print Network (OSTI)

The world’s energy consumption is at a crossroads. While petroleum coffers continuously yield enough petroleum to meet the current state of energy consumption, increases in energy consumption and advancements in technology bear significant weight on our ability to maintain current standards. Looking ahead, plasma fusion is a means of yielding vast amounts of clean, renewable and virtually limitless amounts of energy. With many advancements taking place since the 1950’s, the current Tokamak reactor claims to be able to produce more energy than it consumes, realizing a dream over 60 years in the making. Many characteristics, including plasma density, have to be tuned to maintain optimal conditions. By using finite element method embodied in COMSOL and first principles, one attempts to show how the plasma density evolves through a Tokomak’s modes of operation and to quantify the density against a known standard.

Morelli, Franco

2011-12-01T23:59:59.000Z

373

Modelling charge transfer reactions with the frozen density embedding formalism  

SciTech Connect

The frozen density embedding (FDE) subsystem formulation of density-functional theory is a useful tool for studying charge transfer reactions. In this work charge-localized, diabatic states are generated directly with FDE and used to calculate electronic couplings of hole transfer reactions in two {pi}-stacked nucleobase dimers of B-DNA: 5{sup '}-GG-3{sup '} and 5{sup '}-GT-3{sup '}. The calculations rely on two assumptions: the two-state model, and a small differential overlap between donor and acceptor subsystem densities. The resulting electronic couplings agree well with benchmark values for those exchange-correlation functionals that contain a high percentage of exact exchange. Instead, when semilocal GGA functionals are used the electronic couplings are grossly overestimated.

Pavanello, Michele [Gorlaeus Laboratories, Leiden Institute of Chemistry, Leiden University, P.O. Box 9502, 2300 RA Leiden (Netherlands); Neugebauer, Johannes [Institute for Physical and Theoretical Chemistry, Technische Universitaet Braunschweig, Hans-Sommer-Strasse 10, 38106 Braunschweig (Germany)

2011-12-21T23:59:59.000Z

374

The dependence of natural graphite anode performance on electrode density  

DOE Green Energy (OSTI)

The effect of electrode density for lithium intercalation and irreversible capacity loss on the natural graphite anode in lithium ion batteries was studied by electrochemical methods. Both the first-cycle reversible and irreversible capacities of the natural graphite anode decreased with an increase in the anode density though compression. The reduction in reversible capacity was attributed to a reduction in the chemical diffusion coefficient for lithium though partially agglomerated particles with a larger stress. For the natural graphite in this study the potentials for Li (de)insertion shifted between the first and second formation cycles and the extent of this shift was dependent on electrode density. The relation between this peak shift and the irreversible capacity loss are probably both due to the decrease in graphite surface area with compression.

Shim, Joongpyo; Striebel, Kathryn A.

2003-11-01T23:59:59.000Z

375

Energy Density Functional for Nuclei and Neutron Stars  

Science Conference Proceedings (OSTI)

Background: Recent observational data on neutron star masses and radii provide stringent constraints on the equation of state of neutron rich matter [ Annu. Rev. Nucl. Part. Sci. 62 485 (2012)]. Purpose: We aim to develop a nuclear energy density functional that can be simultaneously applied to finite nuclei and neutron stars. Methods: We use the self-consistent nuclear density functional theory (DFT) with Skyrme energy density functionals and covariance analysis to assess correlations between observables for finite nuclei and neutron stars. In a first step two energy functionals a high density energy functional giving reasonable neutron properties, and a low density functional fitted to nuclear properties are matched. In a second step, we optimize a new functional using exactly the same protocol as in earlier studies pertaining to nuclei but now including neutron star data. This allows direct comparisons of performance of the new functional relative to the standard one. Results: The new functional TOV-min yields results for nuclear bulk properties (energy, rms radius, diffraction radius, and surface thickness) that are of the same quality as those obtained with the established Skyrme functionals, including SV-min. When comparing SV-min and TOV-min, isoscalar nuclear matter indicators vary slightly while isovector properties are changed considerably. We discuss neutron skins, dipole polarizability, separation energies of the heaviest elements, and proton and neutron drip lines. We confirm a correlation between the neutron skin of 208Pb and the neutron star radius. Conclusions: We demonstrate that standard energy density functionals optimized to nuclear data do not carry information on the expected maximum neutron star mass, and that predictions can only be made within an extremely broad uncertainty band. For atomic nuclei, the new functional TOV-min performs at least as well as the standard nuclear functionals, but it also reproduces expected neutron star data within assumed error bands. This functional is expected to yield more reliable predictions in the region of very neutron rich heavy nuclei.

Erler, J. [UTK/ORNL/German Cancer Research Center-Heidelberg; Horowitz, C. J. [UTK/ORNL/Indiana University; Nazarewicz, Witold [UTK/ORNL/University of Warsaw; Rafalski, M. [UTK/ORNL; Reinhard, P.-G. [Universitat Erlangen, Germany

2013-01-01T23:59:59.000Z

376

THE COLUMN DENSITY VARIANCE-M{sub s} RELATIONSHIP  

SciTech Connect

Although there is a wealth of column density tracers for both the molecular and diffuse interstellar medium, there are few observational studies investigating the relationship between the density variance ({sigma}{sup 2}) and the sonic Mach number (M{sub s}). This is in part due to the fact that the {sigma}{sup 2}-M{sub s} relationship is derived, via MHD simulations, for the three-dimensional (3D) density variance only, which is not a direct observable. We investigate the utility of a 2D column density {sigma}{sub {Sigma}/{Sigma}0}{sup 2}-M{sub s} relationship using solenoidally driven isothermal MHD simulations and find that the best fit follows closely the form of the 3D density {sigma}{sub {rho}/{rho}0}{sup 2}-M{sub s} trend but includes a scaling parameter A such that {sigma}{sub ln({Sigma}/{Sigma}o)} = A x ln(1+b{sup 2} M{sub s}{sup 2}), where A = 0.11 and b = 1/3. This relation is consistent with the observational data reported for the Taurus and IC 5146 molecular clouds with b = 0.5 and A = 0.16, and b = 0.5 and A = 0.12, respectively. These results open up the possibility of using the 2D column density values of {sigma}{sup 2} for investigations of the relation between the sonic Mach number and the probability distribution function (PDF) variance in addition to existing PDF sonic Mach number relations.

Burkhart, Blakesley; Lazarian, A. [Astronomy Department, University of Wisconsin, Madison, 475 N. Charter St., WI 53706 (United States)

2012-08-10T23:59:59.000Z

377

Activity report  

SciTech Connect

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.

Yu, S W

2008-08-11T23:59:59.000Z

378

High Energy Density Laboratory Plasmas | National Nuclear Security  

National Nuclear Security Administration (NNSA)

| National Nuclear Security | National Nuclear Security Administration Our Mission Managing the Stockpile Preventing Proliferation Powering the Nuclear Navy Emergency Response Recapitalizing Our Infrastructure Continuing Management Reform Countering Nuclear Terrorism About Us Our Programs Our History Who We Are Our Leadership Our Locations Budget Our Operations Media Room Congressional Testimony Fact Sheets Newsletters Press Releases Speeches Events Social Media Video Gallery Photo Gallery NNSA Archive Federal Employment Apply for Our Jobs Our Jobs Working at NNSA Blog HEDLP High Energy Density Laboratory Plasmas Home > About Us > Our Programs > Defense Programs > Office of Research, Development, Test, and Evaluation > University Partnerships / Academic Alliances > High Energy Density Laboratory Plasmas

379

Study of nuclear matter density distributions using hadronic probes  

Science Conference Proceedings (OSTI)

We briefly review our formula for a proton-nucleus total reaction cross section, {sigma}{sub R}, constructed in the black-sphere approximation of nuclei, in which a nucleus is viewed as a 'black' sphere of radius 'a'. Some years ago, using the Glauber model, one of the authors (A.K.) and his collaborators performed numerical simulations to examine the possibility to probe the nuclear matter density distributions of neutron-rich unstable nuclei from proton elastic scatterings 'model-independently'. The present study is another attempt to seek a 'model-independent' framework for systematically analyzing scattering data for studying the matter density distributions of atomic nuclei.

Kohama, Akihisa [RIKEN Nishina Center, RIKEN, Saitama (Japan); Iida, Kei [Department of Natural Science, Faculty of Science, Kochi University, Kochi (Japan); Oyamatsu, Kazuhiro [Department of Library and Information Science, Faculty of Letters, Aichi Shukutoku University, Aichi (Japan)

2011-05-06T23:59:59.000Z

380

Angular momentum dependence of the nuclear level density parameter  

SciTech Connect

Dependence of nuclear level density parameter on the angular momentum and temperature is investigated in a theoretical framework using the statistical theory of hot rotating nuclei. The structural effects are incorporated by including shell correction, shape, and deformation. The nuclei around Zapprox =50 with an excitation energy range of 30 to 40 MeV are considered. The calculations are in good agreement with the experimentally deduced inverse level density parameter values especially for {sup 109}In, {sup 113}Sb, {sup 122}Te, {sup 123}I, and {sup 127}Cs nuclei.

Aggarwal, Mamta [UM-DAE Centre for Excellence in Basic Sciences, University of Mumbai-Kalina Campus, Mumbai 400 098 (India); Kailas, S. [Nuclear Physics Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India)

2010-04-15T23:59:59.000Z

Note: This page contains sample records for the topic "activity population density" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


381

Neutron spectroscopy of high-density amorphous ice.  

DOE Green Energy (OSTI)

Vibrational spectra of high-density amorphous ice (hda-ice) for H{sub 2}O and D{sub 2}O samples were measured by inelastic neutron scattering. The measured spectra of hda-ice are closer to those for high-pressure phase ice-VI, but not for low-density ice-Ih. This result suggests that similar to ice-VI the structure of hda-ice should consist of two interpenetrating hydrogen-bonded networks having no hydrogen bonds between themselves.

Kolesnikov, A. I.

1998-07-17T23:59:59.000Z

382

Density functional theory and optimal transportation with Coulomb cost  

E-Print Network (OSTI)

We present here novel insight into exchange-correlation functionals in density functional theory, based on the viewpoint of optimal transport. We show that in the case of two electrons and in the semiclassical limit, the exact exchange-correlation functional reduces to a very interesting functional of novel form, which depends on an optimal transport map $T$ associated with a given density $\\rho$. Since the above limit is strongly correlated, the limit functional yields insight into electron correlations. We prove the existence and uniqueness of such an optimal map for any number of electrons and each $\\rho$, and determine the map explicitly in the case when $\\rho$ is radially symmetric.

Codina Cotar; Gero Friesecke; Claudia Klüppelberg

2011-04-04T23:59:59.000Z

383

Exact-exchange density functional theory for neutron drops  

Science Conference Proceedings (OSTI)

We compute the ground-state properties of finite systems of neutrons in an external harmonic trap, interacting via the Minnesota potential, using the ''exact-exchange'' form of orbital-dependent density functional theory. We compare our results with Hartree-Fock calculations and find very close agreement. Within the context of the interaction studied, we conclude that this simple orbital-dependent functional brings conventional nuclear density functional theory to the level of Hartree-Fock in an ab initio fashion. Our work is a first step toward higher order ab initio nuclear functionals based on realistic nucleon-nucleon interactions.

Drut, Joaquin E. [Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545-0001 (United States); Department of Physics, Ohio State University, Columbus, Ohio 43210-1117 (United States); Platter, Lucas [Fundamental Physics, Chalmers University of Technology, SE-41296 Goeteborg (Sweden); Institute for Nuclear Theory, University of Washington, Seattle, Washington 98195 (United States); Department of Physics, Ohio State University, Columbus, Ohio 43210-1117 (United States)

2011-07-15T23:59:59.000Z

384

Nonlinear eigenvalue problems in Density Functional Theory calculations  

SciTech Connect

Developed in the 1960's by W. Kohn and coauthors, Density Functional Theory (DFT) is a very popular quantum model for First-Principles simulations in chemistry and material sciences. It allows calculations of systems made of hundreds of atoms. Indeed DFT reduces the 3N-dimensional Schroedinger electronic structure problem to the search for a ground state electronic density in 3D. In practice it leads to the search for N electronic wave functions solutions of an energy minimization problem in 3D, or equivalently the solution of an eigenvalue problem with a non-linear operator.

Fattebert, J

2009-08-28T23:59:59.000Z

385

Generalized One-Particle Density Matrices and Quasifree States  

E-Print Network (OSTI)

In the spirit of the generalized one-particle density matrix for fermions, we introduce generalized one- and two-particle density matrices to state representability conditions up to second order for boson systems without assuming particle number-conservation. Furthermore, we show for both particle species that, for a semibounded Hamiltonian, the in?mum of the variation of the energy functional w.r.t quasifree states coincides with the one of a variation over pure quasifree states. Moreover, it is proven for fermions that only pure quasifree states have a generalized 1-pdm that is a projection, and a similar statement for bosons.

Volker Bach; Sébastien Breteaux; Hans Konrad Knörr; Edmund Menge

2013-04-30T23:59:59.000Z

386

Low density microcellular carbon foams and method of preparation  

DOE Patents (OSTI)

A low density, open-celled microcellular carbon foam is disclosed which is prepared by dissolving a carbonizable polymer or copolymer in a solvent, pouring the solution into a mold, cooling the solution, removing the solvent, and then carbonizing the polymer or copolymer in a high temperature oven to produce the foam. If desired, an additive can be introduced in order to produce a doped carbon foam, and the foams can be made isotropic by selection of a suitable solvent. The low density, microcellular foams produced by this process are particularly useful in the fabrication of inertial confinement fusion targets, but can also be used as catalysts, absorbents, and electrodes.

Arnold, C. Jr.; Aubert, J.H.; Clough, R.L.; Rand, P.B.; Sylwester, A.P.

1988-06-20T23:59:59.000Z

387

Quasi-equilibrium electron density along a magnetic field line  

SciTech Connect

A methodology is developed to determine the density of high-energy electrons along a magnetic field line for a low-{beta} plasma. This method avoids the expense and statistical noise of traditional particle tracking techniques commonly used for high-energy electrons in bombardment plasma generators. By preserving the magnetic mirror and assuming a mixing timescale, typically the elastic collision frequency with neutrals, a quasi-equilibrium electron distribution can be calculated. Following the transient decay, the analysis shows that both the normalized density and the reduction fraction due to collision converge to a single quasi-equilibrium solution.

Mao, Hann-Shin; Wirz, Richard [Department of Mechanical and Aerospace Engineering, University of California, Los Angeles, California 90095 (United States)

2012-11-26T23:59:59.000Z

388

Small-scale density fluctuations in the adiabatic toroidal compressor  

SciTech Connect

A new class of density fluctuations has been observed in the ATC tokamak by using spectral analysis of scattered microwaves. The observed frequency spectrum is consistent with that of drift waves with amplitudes that are maximum in the wavelength range 0.5 to 1.0 cm where finite ion Larmor radius effects are important for plasma stability. The total density fluctuation is n tilde/sub e/ greater than or equal to 5 x 10$sup -3$ anti n/sub e/. It is estimated that these fluctuations could account for a large fraction of the electron energy losses of the ATC discharge. (auth)

Mazzucato, E.

1976-02-01T23:59:59.000Z

389

The gravitational field energy density for symmetrical and asymmetrical systems  

E-Print Network (OSTI)

The relativistic theory of gravitation has the considerable difficulties by description of the gravitational field energy. Pseudotensor t00 in the some cases cannot be interpreted as energy density of the gravitational field. In [1] the approach was proposed, which allow to express the energy density of such a field through the components of a metric tensor. This approach based on the consideration of the isothermal compression of the layer consisted of the incoherent matter. It was employ to the cylindrically and spherically symmetrical static gravitational field. In presented paper the approach is developed.

Roald Sosnovskiy

2006-07-25T23:59:59.000Z

390

Low density microcellular carbon foams and method of preparation  

SciTech Connect

A low density, open-celled microcellular carbon foam is disclosed which is prepared by dissolving a carbonizable polymer or copolymer in a solvent, pouring the solution into a mold, cooling the solution, removing the solvent, and then carbonizing the polymer or copolymer in a high temperature oven to produce the foam. If desired, an additive can be introduced in order to produce a doped carbon foam, and the foams can be made isotropic by selection of a suitable solvent. The low density, microcellular foams produced by this process are particularly useful in the fabrication of inertial confinement fusion targets, but can also be used as catalysts, absorbents, and electrodes.

Arnold, Jr., Charles (Albuquerque, NM); Aubert, James H. (Albuquerque, NM); Clough, Roger L. (Albuquerque, NM); Rand, Peter B. (Albuquerque, NM); Sylwester, Alan P. (Albuquerque, NM)

1989-01-01T23:59:59.000Z

391

Ecosystem-specific selection pressures revealed through comparative population genomics  

E-Print Network (OSTI)

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 ...

Coleman, Maureen L.

392

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

E-Print Network (OSTI)

Daniel Sperling. 2011. “China’s Soaring Vehicle Population:the longer version, “China’s Soaring Vehicle Population:Vehicle Sales and Stock in China,” Energy Policy, 43: 17–29.

Wang, Yunshi; Teter, Jacob; Sperling, Daniel

2012-01-01T23:59:59.000Z

393

Nuclear Stellar Populations in the Infrared Space Observatory Atlas of Bright Spiral Galaxies  

E-Print Network (OSTI)

To understand the nuclear stellar populations and star formation histories of the nuclei of spiral galaxies, we have obtained K-band nuclear spectra for 41 galaxies and H-band spectra for 20 galaxies in the ISO Atlas of Bright Spiral Galaxies. In the vast majority of the subsample (80%), the near-infrared spectra suggest that evolved red stars completely dominate the nuclear stellar populations and that hot young stars are virtually non-existent. The signatures of recent star formation activity are only found in 20% of the subsample, even though older red stars still dominate the stellar populations in these galaxies. Given the dominance of evolved stars in most galaxy nuclei and the nature of the emission lines in the galaxies where they were detected, we suggest that nuclear star formation proceeds in the form of instantaneous bursts. The stars produced by these bursts comprise only ~2% of the total nuclear stellar mass in these galaxies, but we demonstrate how the nuclear stellar populations of normal spiral galaxies can be built up through a series of these bursts. The bursts were detected only in Sbc galaxies and later, and both bars and interactions appeared to be sufficient but not necessary triggers for the nuclear star formation activity. The vast majority of galaxies with nuclear star formation were classified as HII galaxies. With one exception, LINERs and transition objects were dominated by older red stars, which suggested that star formation was not responsible for generating these galaxies' optical line emission.

George J. Bendo; Robert D. Joseph

2004-03-04T23:59:59.000Z

394

The Use of the Weibull Three-Parameter Model for Estimating Mean Wind Power Densities  

Science Conference Proceedings (OSTI)

The Weibull three-parameter model is discussed for estimation of mean wind power densities. This probability density function is a generalization of a number of more conventional density functions. Using wind speed observations, it is shown that ...

L. Van Der Auwera; F. De Meyer; L. M. Malet

1980-07-01T23:59:59.000Z

395

The Impact of Residential Density on Vehicle Usage and Energy Consumption  

E-Print Network (OSTI)

DC. Steiner, R.L. (1994). Residential density and traveland Brownstone The Impact of Residential Density on VehicleWP-05-1 The Impact of Residential Density on Vehicle Usage

Golob, Thomas F; Brownstone, David

2005-01-01T23:59:59.000Z

396

How Do Recent Population Trends Matter to Climate Change?  

E-Print Network (OSTI)

. By ensuring couples are able to determine the size of their families, poverty and the depletion of natural change, as one of the root causes of greenhouse gas emissions, how population dynamics affect climate of total population size, research shows that changes in population composition (i.e. age, urban

Colorado at Boulder, University of

397

Identifying phylogeographic patterns and population history in Mediterranean rock ferns  

E-Print Network (OSTI)

, Q-matrix plots of K=2 through K=5 for 53 sampled populations All populations N>15 -30000 -25000 -20000 -15000 -10000 -5000 0 1 2 3 4 5 6 K L n P ( D ) 0 200 400 600 800 1000 1200 1400 1600 D e l t a K Populations n>15 excluding Valencia -14600...

Hunt, Harriet

2010-06-24T23:59:59.000Z

398

Laboratory Activities  

Science Conference Proceedings (OSTI)

This chapter summarizes the laboratory activities performed by PNNL’s Vadose Zone Characterization Project in support of the Tank Farm Vadose Zone Program, led by CH2M HILL Hanford Group, Inc. The results of these studies are contained in numerous reports (Lindenmeier et al. 2002; Serne et al. 2002a, 2002b, 2002c, 2002d, 2002e; Lindenmeier et al. 2003; Serne et al. 2004a, 2004b; Brown et al. 2005, 2006a, 2007; Serne et al. 2007) and have generated much of the data reported in Chapter 22 (Geochemistry-Contaminant Movement), Appendix G (Geochemistry-Contaminant Movement), and Cantrell et al. (2007, SST WMA Geochemistry Data Package – in preparation). Sediment samples and characterization results from PNNL’s Vadose Zone Characterization Project are also shared with other science and technology (S&T) research projects, such as those summarized in Chapter 12 (Associated Science Activities).

Brown, Christopher F.; Serne, R. Jeffrey

2008-01-17T23:59:59.000Z

399

The Biermann Battery in Cosmological MHD Simulations of Population III Star Formation  

E-Print Network (OSTI)

We report the results of the first self-consistent three-dimensional adaptive mesh refinement magnetohydrodynamical simulations of Population III star formation including the Biermann Battery effect. We find that the Population III stars formed including this effect are both qualitatively and quantitatively similar to those from hydrodynamics-only (non-MHD) cosmological simulations. We observe peak magnetic fields of ~10^-9 G in the center of our star-forming halo at z ~ 17.55. The magnetic fields created by the Biermann Battery effect are predominantly formed early in the evolution of the primordial halo at low density and large spatial scales, and then grow through compression and by shear flows. The fields seen in this calculation are never large enough to be dynamically important (with beta >= 10^{15} at all times), and should be considered the minimum possible fields in existence during Population III star formation, and may be seed fields for the stellar dynamo or the magnetorotational instability at hi...

Xu, Hao; Collins, David C; Norman, Michael L; Li, Hui; Li, Shengtai

2008-01-01T23:59:59.000Z

400

The Dark Bursts population in a complete sample of bright Swift Long Gamma-Ray Bursts  

E-Print Network (OSTI)

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.

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

2011-12-19T23:59:59.000Z

Note: This page contains sample records for the topic "activity population density" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


401

Parity Dependent Shell Model Level Densities for Nuclear Astrophysics  

E-Print Network (OSTI)

Recently, we developed a methodology [1-4] of calculating the spin and parity dependent shell model nuclear level density, which is a very useful ingredient in the Huaser-Feshbach theory for calculating reaction rates for nuclear astrophysics[5]. We developed new techniques based on nuclear statistical spectroscopy [6] to calculate the spin and parity projected moments of the nuclear shell model Hamiltonian, that can be further used to obtain an accurate description of the nuclear level density up to about 15 MeV excitation energy. These techniques were fully tested for the sd-shell nuclei and some light f p-shell nuclei, by comparing with the level density obtained from exact shell model diagonalization. Here we present for the first time comparisons with the exact shell model diagonalization for nuclei heavier than 56 Ni, in a model space spanned by the f 5/2, p 3/2, p 1/2 and g 9/2 orbits. The ratio of nuclear level densities of opposite parities is also discussed. This analysis was possible due to a new and very efficient nuclear shell model code [7] that can provide a large number of states of given spin and parity. PoS(NIC X)132

Mike Scott; Mihai Horoi; Mike Scott

2008-01-01T23:59:59.000Z

402

On a Density-of-States Approach to Bohmian Mechanics  

E-Print Network (OSTI)

We propose the idea that in Bohmian mechanics the wavefunction is related to a density of states and explore some of its consequences. Specifically, it allows a maximum-entropy interpretation of quantum probabilities, which creates a stronger link between it and statistical mechanics. The proposed approach also allows a range of extensions of the guidance condition in Bohmian mechanics.

Guy Potvin

2005-04-15T23:59:59.000Z

403

Terrace housing : providing quality in higher-density housing  

E-Print Network (OSTI)

The higher demand of higher-density housing in Bangkok due to the rapid growth of the economy and the use of high-performance materials and modern construction methods has changed the forms of housing from low-rise buildings ...

Atthakor, Songpol

1992-01-01T23:59:59.000Z

404

Effect of Larch Forest Density on Snow Surface Energy Balance  

Science Conference Proceedings (OSTI)

It is established that the density of a larch forest strongly influences the snowmelt energy under its canopy. In the spring thaw of 1994, 1995, and 1996, the surface snowmelt at three different sites located at the southern foot of Mt. Iwate, ...

Kazuyoshi Suzuki; Takeshi Ohta

2003-12-01T23:59:59.000Z

405

Finite-Element Solutions of Free-Interface Density Currents  

Science Conference Proceedings (OSTI)

An interface-adaptive finite-element iteration scheme is designed to solve for the free interface of an inviscid steady-state density current. The method is also applied to free-surface flows over finite obstacles, but convergent solutions are ...

Qin Xu; Fu-Shen Zhang; Guang-Ping Lou

1992-01-01T23:59:59.000Z

406

Density-metric unimodular gravity: Vacuum maximal symmetry  

SciTech Connect

We have investigated the vacuum maximally symmetric solutions of recently proposed density-metric unimodular gravity theory. The results are widely different from inflationary scenario. The exponential dependence on time in deSitter space is substituted by a power law. Open space-times with non-zero cosmological constant are excluded.

Abbassi, A.H., E-mail: ahabbasi@modares.ac.ir [Department of Physics, School of Sciences, Tarbiat Modares University, P.O. Box 14155-4838, Tehran (Iran, Islamic Republic of); Abbassi, A.M., E-mail: amabasi@khayam.ut.ac.ir [Department of Physics, University of Tehran, P.O. Box 14155-6455, Tehran (Iran, Islamic Republic of)

2011-05-15T23:59:59.000Z

407

FOAM DENSITY SENSITIVITY STUDY FOR THE 9977 PACKAGE  

SciTech Connect

Two layers of insulation fill the volume of the 9977 package between the drum liner and the shell. One of these layers is composed of General Plastics FR-3716 polyurethane foam (also known as Last-A-Foam{reg_sign}), poured through fill holes in the drum bottom and foamed in place. There was concern that the density of the foam insulating layer may vary due to the manufacturing process and that variations in foam density would compromise the safety basis of the package. Thus, a structural finite element analysis was performed to investigate this concern. The investigation examined the effect of replacing the material properties for the FR-3716 polyurethane foam, which has a density equal to 16 lb{sub m}/ft{sup 3}, with material properties of similar foam with varying densities through finite element analysis of hypothetical accident conditions (HAC) pertaining to impact conditions. The results showed that the functional performance of the containment vessel (CV) was not compromised under the conditions investigated.

Gorczyca, J; Tsu-Te Wu, T

2008-05-02T23:59:59.000Z

408

Prediction of Graupel Density in a Bulk Microphysics Scheme  

Science Conference Proceedings (OSTI)

A method to predict the bulk density of graupel ?g has been added to the two-moment Milbrandt–Yau bulk microphysics scheme. The simulation of graupel using the modified scheme is illustrated through idealized simulations of a mesoscale convective ...

Jason A. Milbrandt; Hugh Morrison

2013-02-01T23:59:59.000Z

409

Improved association in a classical density functional theory for water  

E-Print Network (OSTI)

We present a modification to our recently published SAFT-based classical density functional theory for water. We have recently developed and tested a functional for the averaged radial distribution function at contact of the hard-sphere fluid that is dramatically more accurate at interfaces than earlier approximations. We now incorporate this improved functional into the association term of our free energy functional for water, improving its description of hydrogen bonding. We examine the effect of this improvement by studying two hard solutes: a hard hydrophobic rod and a hard sphere. The improved functional leads to a moderate change in the density profile and a large decrease in the number of hydrogen bonds broken in the vicinity of the solutes.We present a modification to our recently published SAFT-based classical density functional theory for water. We have recently developed and tested a functional for the averaged radial distribution function at contact of the hard-sphere fluid that is dramatically more accurate at interfaces than earlier approximations. We now incorporate this improved functional into the association term of our free energy functional for water, improving its description of hydrogen bonding. We examine the effect of this improvement by studying two hard solutes: a hard hydrophobic rod and a hard sphere. The improved functional leads to a moderate change in the density profile and a large decrease in the number of hydrogen bonds broken in the vicinity of the solutes.

Eric J. Krebs; Jeff B. Schulte; David Roundy

2013-09-07T23:59:59.000Z

410

Reduced Water Density in a Poly(ethylene oxide) Brush  

Science Conference Proceedings (OSTI)

A model poly(ethylene oxide) (PEO) brush system, prepared by spreading a poly(ethylene oxide)-poly(n-butyl acrylate) (PEO-PnBA) amphiphilic diblock copolymer onto an air-water interface, was investigated under various grafting density conditions by using the X-ray reflectivity (XR) technique. The overall electron density profiles of the PEO-PnBA monolayer in the direction normal to the air-water interface were determined from the XR data. From this analysis, it was found that inside of the PEO brush, the water density is significantly lower than that of bulk water, in particular, in the region close to the PnBA-water interface. Separate XR measurements with a PnBA homopolymer monolayer confirm that the reduced water density within the PEO-PnBA monolayer is not due to unfavorable contacts between the PnBA surface and water. The above result, therefore, lends support to the notion that PEO chains provide a hydrophobic environment for the surrounding water molecules when they exist as polymer brush chains.

Lee, Hoyoung; Kim, Dae Hwan; Park, Hae-Woong; Mahynski, Nathan A.; Kim, Kyungil; Meron, Mati; Lin, Binhua; Won, You-Yeon (Purdue); (UC)

2012-09-05T23:59:59.000Z

411

Pressure induced Superconductivity in the Charge Density Wave Compound Tritelluride  

Science Conference Proceedings (OSTI)

A series of high-pressure electrical resistivity measurements on single crystals of TbTe{sub 3} reveal a complex phase diagram involving the interplay of superconducting, antiferromagnetic and charge density wave order. The onset of superconductivity reaches a maximum of almost 4 K (onset) near {approx} 12.4 GPa.

Hamlin, J.J.; Zocco, D.A.; Sayles, T.A.; Maple, M.B.; /UC, Davis; Chu, J.-H.; Fisher, I.R.; /Stanford U., Geballe Lab.

2010-02-15T23:59:59.000Z

412

Thin liquid lithium targets for high power density  

E-Print Network (OSTI)

Thin liquid lithium targets for high power density applications: heavy ion beam strippers and beta Hilton Malmö City #12;Outline Liquid Lithium Stripper idea for FRIB Brief theory of film stability Thickness measurement results Next Steps Beta-beams 2 #12;Liquid Lithium Stripper for FRIB: Advantages

McDonald, Kirk

413

Effects of flow on density profiles in laser irradiated plasmas  

SciTech Connect

When the plasma outflow velocity relative to the critical surface is supersonic, compressional density profiles can form in the critical region. These compressions involve dissipative processes like those in collisionless shocks; associated plasma instabilities and reflected ions may inhibit energy transport and enhance laser light absorption.

Max, C.E.; McKee, C.F.

1977-10-18T23:59:59.000Z

414

Power Density Analysis for a Regenerated Closed Brayton Cycle  

Science Conference Proceedings (OSTI)

In this paper, the power density, defined as the ratio of power output to the maximum specific volume in the cycle, is set as the objective for performance analysis of an irreversible, regenerated and closed Brayton cycle coupled to constant-temperature ...

Lingen Chen; Junlin Zheng; Fengrui Sun; Chih Wu

2001-12-01T23:59:59.000Z

415

Nondestructive Evaluation: High-Density Polyethylene NDE Technology  

Science Conference Proceedings (OSTI)

BackgroundThis report summarizes the results of a study to evaluate and document the process of creating a manufacturing specification for producing quantifiable cold fusion controlled flaws of varying severity in high-density polyethylene (HDPE) fusion joints. This report is a continuation of previous research where nondestructive evaluation (NDE) techniques and flaws representing inclusions and cold fusion were ...

2013-11-22T23:59:59.000Z

416

On the Vertical Extrapolation of Mean Wind Power Density  

Science Conference Proceedings (OSTI)

A simple method of estimating the height variation of the mean wind power density is presented which accounts for the variation of the exponent p of the wind speed power law, with stability and roughness. Measurements are used to compare the new ...

Leon Sedefian

1980-04-01T23:59:59.000Z

417

Calculations of nonspherically averaged charge densities for subtitutionally disordered alloys  

Science Conference Proceedings (OSTI)

Based on screening transformations of muffin-tin orbitals introduced by Andersen et al. [Phys. Rev. Lett. 53, 2571 (1984)], we have developed a formalism for calculating the non-spherically averaged charge densities of substitutionally disordered alloys using the Korringa-Kohn-Rostoker coherent potential approximation (KKR CPA) method in the atomic-sphere approximation (ASA). We have validated our method by calculating charge densities for ordered structures, where we find that our approach yields charge densities that are essentially indistinguishable from the results of full-potential methods. For substitutionally disordered alloys, where full-potential methods have not been implemented so far, our approach can be used to calculate reliable non-spherically averaged charge densities from spherically symmetric one-electron potentials obtained from the KKR-ASA CPA. We report on our study of differences in charge denisty between ordered AlLi in L1{sub o} phase and substitutionally disordered Al{sub 0.5}Li{sub 0.5} on face-centered cubic lattice.

Singh, P.P.; Gonis, A.

1994-02-01T23:59:59.000Z

418

Original article Metabolism of very low density lipoproteins  

E-Print Network (OSTI)

lipoproteins (VLDL) has been compared in fat (FL) and lean (LL) lines of chicken. When refed after fasting VLDL from fat or lean donors were prepared and were injected into chickens from both genotypesOriginal article Metabolism of very low density lipoproteins in genetically lean or fat lines

Recanati, Catherine

419

Density inhomogeneity driven electrostatic shock waves in planetary rings  

SciTech Connect

Dust inertia and background density driven dust drift shock waves are theoretically studied in a rotating planetary environment and are subsequently applied to the planetary rings where the collisional effects are pronounced. It has been found that the system under consideration admits significant shock formation if the collision frequency is of the order of or less than the rotational frequency of the Saturn's rings.

Masood, W.; Siddiq, M. [Theoretical Plasma Physics Division (TPPD), PINSTECH, P. O. Nilore, Islamabad 44000 (Pakistan); National Center for Physics (NCP), Islamabad 44000 (Pakistan); Rizvi, H.; Haque, Q. [Theoretical Plasma Physics Division (TPPD), PINSTECH, P. O. Nilore, Islamabad 44000 (Pakistan); Hasnain, H. [NILOP, P. O. Nilore, Islamabad 44000 (Pakistan); PIEAS, P. O. Nilore, Islamabad 44000 (Pakistan)

2011-05-15T23:59:59.000Z

420

Sub-L* Galaxies at Redshifts z~4, 3, and 2: Their UV Luminosity Function and Luminosity Density  

E-Print Network (OSTI)

We use very deep (R_lim=27) UGRI imaging to study the evolution of the faint end of the UV-selected galaxy luminosity function from z~4 to z~2. We find that the luminosity function evolves with time and that this evolution is differential with luminosity: the number of sub-L* galaxies increases from z~4 to z~3 by at least a factor of 2.3, while the bright end of the LF remains unchanged. Potential systematic biases restrict our ability to draw strong conclusions at lower redshifts, z~2, but we can say that the number density of sub-L* galaxies at z~2.2 is at least as high as it is at z~3. Turning to the UV luminosity density of the Universe, we find that the luminosity density starts dropping with increasing redshift already beginning at z=3 (earlier than recently thought - Steidel et al. 1999) and that this drop is dominated by the same sub-L* galaxies that dominate the evolution of the LF. This differential evolution of the luminosity function suggests that differentially comparing key diagnostics of dust, stellar populations, etc. as a function of z and L should let us isolate the key mechanisms that drive galaxy evolution at high redshift.

Marcin Sawicki; David Thompson

2005-09-15T23:59:59.000Z

Note: This page contains sample records for the topic "activity population density" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


421

Laboratory testing of high energy density capacitors for electric vehicles  

DOE Green Energy (OSTI)

Laboratory tests of advanced, high energy density capacitors in the Battery Test Laboratory of the Idaho National Engineering Laboratory have been performed to investigate their suitability for load-leveling the battery in an electric vehicle. Two types of devices were tested -- 3 V, 70 Farad, spiral wound, carbon-based, single cell devices and 20 V, 3. 5 Farad, mixed-oxide, multi-cell bipolar devices. The energy density of the devices, based on energy stored during charge to the rated voltage, was found to be 1--2 Wh/kg, which agreed well with that claimed by the manufacturers. Constant power discharge tests were performed at power densities up to 1500 W/kg. Discharges at higher power densities could have been performed had equipment been available to maintain constant power during discharges of less than one second. It was found that the capacitance of the devices were rate dependent with the rate dependency of the carbon-based devices being higher than that of the mixed-oxide devices. The resistance of both types of devices were relatively low being 20--30 milliohms. Testing done in the study showed that the advanced high energy density capacitors can be charged and discharged over cycles (PSFUDS) which approximate the duty cycle that would be encountered if the devices are used to load-level the battery in an electric vehicle. Thermal tests of the advanced capacitors in an insulated environment using the PSFUDS cycle showed the devices do not overheat with their temperatures increasing only 4--5{degrees}C for tests that lasted 5--7 hours. 7 refs., 33 figs., 11 tabs.

Burke, A.F.

1991-10-01T23:59:59.000Z

422

The Impact of Residential Density on Vehicle Usage and Energy Consumption  

E-Print Network (OSTI)

residential transportation energy usage is vital for theDensity on Vehicle Usage and Energy Consumption Table 2Density on Vehicle Usage and Energy Consumption with

Golob, Thomas F.; Brownstone, David

2005-01-01T23:59:59.000Z

423

Synthetic Nano-Low Density Lipoprotein as Targeted Drug Delivery Vehicle for Glioblastoma Multiforme  

E-Print Network (OSTI)

Synthetic Nano-Low Density Lipoprotein as Targeted Drugmicroemulsion; peptide; nano-low density lipoproteintherapeutic agents. A synthetic nano-LDL (nLDL) particle was

Nikanjam, Mina; Blakely, Eleanor A.; Bjornstad, Kathleen A.; Shu, Xiao; Budinger, Thomas F.; Forte, Trudy M.

2006-01-01T23:59:59.000Z

424

The impact of residential density on vehicle usage and fuel consumption  

E-Print Network (OSTI)

characteristics on household residential choice and auto2009. The impact of residential density on vehicle usage and2010-05) The impact of residential density on vehicle usage

Kim, Jinwon; Brownstone, David

2010-01-01T23:59:59.000Z

425

The Impact of Residential Density on Vehicle Usage and Energy Consumption  

E-Print Network (OSTI)

DC. Steiner, R.L. (1994). Residential density and traveland Brownstone The Impact of Residential Density on VehicleUsage Total annual residential vehicular energy consumption

Golob, Thomas F.; Brownstone, David

2005-01-01T23:59:59.000Z

426

Dworshak Kokanee Population and Entrainment Assessment 2005-2006 Annual Report.  

DOE Green Energy (OSTI)

During this contract, we continued testing underwater strobe lights to determine their effectiveness at repelling kokanee Oncorhynchus nerka away from Dworshak Dam. We tested one set of nine strobe lights flashing at a rate of 360 flashes/min in front of turbine 3 while operating at higher discharges than previously tested. 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 five nights between January 31 and February 28, 2006, when no lights were present, fish counts near turbine 3 averaged eight fish and densities averaged 91 fish/ha. When strobe lights were turned on during five adjacent nights during the same period, mean counts dropped to four fish and densities dropped to 35 fish/ha. The decline in counts (49%) was not statistically significant (p = 0.182), but decline in densities (62%) was significant (p = 0.049). There appeared to be no tendency for fish to habituate to the lights during the night. Test results indicated that strobe lights were able to reduce fish densities by at least 50% in front of turbines operating at higher discharges, which would be sufficient to improve sportfish harvest. We also used split-beam hydroacoustics to monitor the kokanee population in Dworshak Reservoir during 2005. Estimated abundance of kokanee decreased from the 2004 population estimate. Based on hydroacoustic surveys, we estimated 3,011,626 kokanee (90% CI {+-} 15.2%) in Dworshak Reservoir, July 2005. This included 2,135,986 age-0 (90% CI {+-} 15.9%), 769,175 age-1 (90% CI {+-} 16.0%), and 107,465 age-2 (90% CI {+-} 15.2%). Poor survival of kokanee from age-1 to age-2 continued to keep age-2 densities below the management goal of 30-50 adults/ha. Entrainment sampling was conducted with fixed-site split-beam hydroacoustics a minimum of two days per month for a continuous 24 h period when dam operations permitted. The highest fish detection rates from entrainment assessments were again found during nighttime periods and lowest during the day. Fish detection rates were low during high discharges throughout the spring and summer and highest during low discharges in September and November. High discharge during drawdowns for anadromous fish flows in July and August again resulted in low detection rates and susceptibility to entrainment. Index counts of spawning kokanee in four tributary streams totaled 12,742 fish. This data fits the previously developed relationship between spawner counts and adult kokanee abundance in the reservoir.

Stark, Eric J. [Idaho Department of Fish and Game

2008-11-06T23:59:59.000Z

427

The distribution of stellar population age in galactic bars  

E-Print Network (OSTI)

Recent analysis of stellar populations in barred galaxies have focused on the spatial distribution of stellar population ages and metallicities. However, barred galaxies are complex objects where dynamical instabilities play a leading role in shaping any spatial distribution. The age distribution of stellar populations should thus be analyzed from the two points of view of stellar population evolution and dynamical secular evolution. Chemodynamical simulations of single barred galaxies with simple but realistic star formation and feedback recipes are used to produce face-on mass-weighted maps of stellar population ages. Luminosity-weighted maps in V-band are also displayed after calibrating the simulation with mass-to-light ratios provided by a synthesis population model. It is shown that inside a stellar bar two persistent diametrically opposed regions display a mean age lower than the surrounding average. These two low-age regions are due to the accumulation of young stellar populations trapped on elliptica...

Wozniak, H

2007-01-01T23:59:59.000Z

428

ORIGINAL ARTICLE RAF kinase inhibitor-independent constitutive activation of  

E-Print Network (OSTI)

OPEN ORIGINAL ARTICLE RAF kinase inhibitor-independent constitutive activation of Yes the BRAFV600E mutation, regardless of cell density. Furthermore, the nuclear activation of YAP1 in 8505C; drug resistance INTRODUCTION Thyroid cancer is the leading cause of morbidity and mortality

Cai, Long

429

Microscopically-based energy density functionals for nuclei using the density matrix expansion: Implementation and pre-optimization  

E-Print Network (OSTI)

In a recent series of papers, Gebremariam, Bogner, and Duguet derived a microscopically based nuclear energy density functional by applying the Density Matrix Expansion (DME) to the Hartree-Fock energy obtained from chiral effective field theory (EFT) two- and three-nucleon interactions. Due to the structure of the chiral interactions, each coupling in the DME functional is given as the sum of a coupling constant arising from zero-range contact interactions and a coupling function of the density arising from the finite-range pion exchanges. Since the contact contributions have essentially the same structure as those entering empirical Skyrme functionals, a microscopically guided Skyrme phenomenology has been suggested in which the contact terms in the DME functional are released for optimization to finite-density observables to capture short-range correlation energy contributions from beyond Hartree-Fock. The present paper is the first attempt to assess the ability of the newly suggested DME functional, which has a much richer set of density dependencies than traditional Skyrme functionals, to generate sensible and stable results for nuclear applications. The results of the first proof-of-principle calculations are given, and numerous practical issues related to the implementation of the new functional in existing Skyrme codes are discussed. Using a restricted singular value decomposition (SVD) optimization procedure, it is found that the new DME functional gives numerically stable results and exhibits a small but systematic reduction of our test $\\chi^2$ function compared to standard Skyrme functionals, thus justifying its suitability for future global optimizations and large-scale calculations.

M. Stoitsov; M. Kortelainen; S. K. Bogner; T. Duguet; R. J. Furnstahl; B. Gebremariam; N. Schunck

2010-09-17T23:59:59.000Z

430

DNA Activity  

NLE Websites -- All DOE Office Websites (Extended Search)

DNA Activity DNA Activity Name: Sara Location: N/A Country: N/A Date: N/A Question: Is DNA an anion or a cation? I thought since it was negatively charged it was an anion but mt teacher in class today said it was a cation because negatively charged molecules logically migrate to the positively charged plate of the cathode, ie molecules that migrate towards a cathode are cations. Where is the error in my logic or there error in my logic? Replies: DNA is negatively charged due to the phosphate ions present in the ribose-phosphate backbone. It moves towards the positive pole during electrophoresis. The definition kation/anion is confusing because: 1. a cation moves to the cathode 2. the cathode is negative, thus 3. a cation is positive DNA is an anion. The confusion is that a cathode is negative, but a cation is positively charged. For that reason these terms are not generally used in this context.

431

Role of density dependent symmetry energy in nuclear stopping  

E-Print Network (OSTI)

Information about the nuclear matter under the extreme conditions of temperature and density and the role of symmetry energy under these conditions is still a topic of crucial importance in the present day nuclear physics research. The multifragmentation, collective flow and the nuclear stopping is among the various rare phenomenon which can be observed in heavy-ion collisions at intermediate energies. The nuclear stopping, which is sensitive towards the symmetry energy has gained a lot of interest because it provides the possibility to examine the degree of thermalization or equilibration in the matter. Aim of the present study is to pin down the nuclear stopping for the different forms of density dependent symmetry energy

Vinayak, Karan Singh

2011-01-01T23:59:59.000Z

432

Role of density dependent symmetry energy in nuclear stopping  

E-Print Network (OSTI)

Information about the nuclear matter under the extreme conditions of temperature and density and the role of symmetry energy under these conditions is still a topic of crucial importance in the present day nuclear physics research. The multifragmentation, collective flow and the nuclear stopping is among the various rare phenomenon which can be observed in heavy-ion collisions at intermediate energies. The nuclear stopping, which is sensitive towards the symmetry energy has gained a lot of interest because it provides the possibility to examine the degree of thermalization or equilibration in the matter. Aim of the present study is to pin down the nuclear stopping for the different forms of density dependent symmetry energy

Karan Singh Vinayak; Suneel Kumar

2011-07-27T23:59:59.000Z

433

Interferometric measurements of plasma density in high-. beta. plasmas  

SciTech Connect

The coupled-cavity laser interferometer technique is particularly applicable to the measurement of pulsed plasma densities. This technique is based on the fact that if a small fraction of a gas laser's output radiation is reflected into the laser with an external mirror, the intensity of the laser output is modulated. These amplitude or intensity modulations are produced by changes in the laser gain. A rotating corner mirror or an oscillating mirror can be used to produce a continuous feedback modulation of the interferometer which produces a continuous background fringe pattern. The presence of plasma in the outer cavity causes an additional change which results in a phase shift of the regular period of the background fringe pattern. The integral of the plasma density along the line of sight can be evaluated by comparison of the time history of the fringes obtained with and without plasma.

Quinn, W.E.

1977-01-01T23:59:59.000Z

434

VOYAGER 2 OBSERVES A LARGE DENSITY INCREASE IN THE HELIOSHEATH  

Science Conference Proceedings (OSTI)

Voyager 2 (V2) entered the heliosheath in 2007 August at roughly the same time solar minimum conditions were reaching the outer heliosphere. Soon after crossing the termination shock the solar wind density at Voyager decreased by a factor of two and the temperature decreased by a factor of three. At the beginning of 2011 the plasma density in the heliosheath began to increase and in mid-2012 it was up by more than a factor of two. The temperature rose by about 50% and the speed remained constant, although the flow direction continues to turn tailward. These changes may signal the end of solar minimum conditions at V2 in the heliosheath, although we do not understand why the speed did not decrease. The increased dynamic pressure has lead to an outward movement of the termination shock from its very compressed state at solar minimum.

Richardson, J. D. [Kavli Center for Astrophysics and Space Research, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Wang, C., E-mail: jdr@space.mit.edu, E-mail: cw@spaceweather.ac.cn [State Key Laboratory for Space Weather, Chinese Academy of Sciences, Beijing (China)

2012-11-01T23:59:59.000Z

435

Classical Phase Space Density for the Relativistic Hydrogen Atom  

E-Print Network (OSTI)

Quantum mechanics is considered to arise from an underlying classical structure (``hidden variable theory'', ``sub-quantum mechanics''), where quantum fluctuations follow from a physical noise mechanism. The stability of the hydrogen ground state can then arise from a balance between Lorentz damping and energy absorption from the noise. Since the damping is weak, the ground state phase space density should predominantly be a function of the conserved quantities, energy and angular momentum. A candidate for this phase space density is constructed for ground state of the relativistic hydrogen problem of a spinless particle. The first excited states and their spherical harmonics are also considered in this framework. The analytic expression of the ground state energy can be reproduced, provided averages of certain products are replaced by products of averages. This analysis puts forward that quantum mechanics may arise from an underlying classical level as a slow variable theory, where each new quantum operator relates to a new, well separated time interval.

Th. M. Nieuwenhuizen

2005-11-15T23:59:59.000Z

436

Plasma wave propagation with a plasma density gradient  

Science Conference Proceedings (OSTI)

Plasma waves with the plasma diffusion velocity u{sub n} due to a plasma density gradient are described in a positive column plasma. The ion wave is generated by the perturbation of the operating frequency 10{sup 6} s{sup -1} and it propagates with the group velocity u{sub g{approx}}c{sub s}{sup 2}/u{sub n{approx}}(10{sup 5}-10{sup 6}) m/s, where c{sub s} is the acoustic velocity in a fine tube fluorescent lamp, while the electron wave cannot be generated with a turbulence of low frequency less than the electron oscillation frequency {omega}{sub pe}. The propagation of the lighting signal observed in long tube fluorescent lamps is well understood with the propagation of ion waves occurring along the plasma density gradient.

Cho, Guangsup; Choi, Eun-Ha; Uhm, Han Sup [Department of Electrophysics, Kwangwoon University, 447-1 Nowon Wallgye, Seoul 139-701 (Korea, Republic of)

2011-03-15T23:59:59.000Z

437

Density Functional Theory for the Photoionization Dynamics of Uracil  

E-Print Network (OSTI)

Photoionization dynamics of the RNA base Uracil is studied in the framework of Density Functional Theory (DFT). The photoionization calculations take advantage of a newly developed parallel version of a multicentric approach to the calculation of the electronic continuum spectrum which uses a set of B-spline radial basis functions and a Kohn-Sham density functional hamiltonian. Both valence and core ionizations are considered. Scattering resonances in selected single-particle ionization channels are classified by the symmetry of the resonant state and the peak energy position in the photoelectron kinetic energy scale; the present results highlight once more the site specificity of core ionization processes. We further suggest that the resonant structures previously characterized in low-energy electron collision experiments are partly shifted below threshold by the photoionization processes. A critical evaluation of the theoretical results providing a guide for future experimental work on similar biosystems.

Toffoli, D; Gianturco, F A; Lucchese, R R

2007-01-01T23:59:59.000Z

438

Electrostatic lens to focus an ion beam to uniform density  

SciTech Connect

A focusing lens for an ion beam having a gaussian or similar density profile is provided. The lens is constructed to provide an inner zero electrostatic field, and an outer electrostatic field such that ions entering this outer field are deflected by an amount that is a function of their distance from the edge of the inner field. The result is a beam that focuses to a uniform density in a manner analogous to that of an optical ring lens. In one embodiment, a conically-shaped network of fine wires is enclosed within a cylindrical anode. The wire net together with the anode produces a voltage field that re-directs the outer particles of the beam while the axial particles pass undeflected through a zero field inside the wire net. The result is a focused beam having a uniform intensity over a given target area and at a given distance from the lens.

Johnson, Cleland H. (Oak Ridge, TN)

1977-01-11T23:59:59.000Z

439

Limits to the power density of very large wind farms  

E-Print Network (OSTI)

A simple analysis is presented concerning an upper limit of the power density (power per unit land area) of a very large wind farm located at the bottom of a fully developed boundary layer. The analysis suggests that the limit of the power density is about 0.38 times $\\tau_{w0}U_{F0}$, where $\\tau_{w0}$ is the natural shear stress on the ground (that is observed before constructing the wind farm) and $U_{F0}$ is the natural or undisturbed wind speed averaged across the height of the farm to be constructed. Importantly, this implies that the maximum extractable power from such a very large wind farm will not be proportional to the cubic of the wind speed at the farm height, or even the farm height itself, but be proportional to $U_{F0}$.

Nishino, Takafumi

2013-01-01T23:59:59.000Z

440

Electron number density measurement by ruby laser interferometry  

DOE Green Energy (OSTI)

A pulsed ruby laser beam with 3 nsec full width at half magnitude is used to obtain space- and time-resolved, two-dimensional interferometric measurements of electron number density in CO/sub 2/-laser produced plasma in hydrogen near the focal spot. The focal plane of the CO/sub 2/ laser is arranged to be at the exit of a free-expansion jet, with the beam incident from the vacuum side. Several nanoseconds after breakdown, a shock wave is formed, propagating transverse to the incident laser beam direction. Behind the transverse propagating shock is an on axis density minimum, which results in laser-beam self trapping. During the initial pulse duration of the CO/sub 2/ laser, the radial boundary of the plasma column increases linearly in time.

Chu, T.K.; Johnson, L.C.; Schuss, J.J.

1977-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "activity population density" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


441

Ultra-low density microcellular polymer foam and method  

DOE Patents (OSTI)

An ultra-low density, microcellular open-celled polymer foam and a method for making such foam are disclosed. A polymer is dissolved in a heated solution consisting essentially of at least one solvent for the dissolution of the polymer in the heated solution and the phase inversion of the dissolved polymer to a liquid gel upon sufficient cooling of the heated solution. The heated solution is contained in a containment means provided with a nucleating promoting means having a relatively rough surface formed of fixed nucleating sites. The heated solution is cooled for a period of time sufficient to form a liquid gel of the polymer by phase inversion. From the gel, a porous foam having a density of less than about 12.0 mg/cm{sup 3} and open porosity provided by well interconnected strut morphology is formed. These foams can be used for ICF targets.

Simandl, R.F.; Brown, J.D.

1995-12-31T23:59:59.000Z

442

Tunable Laser Plasma Accelerator based on Longitudinal Density Tailoring  

Science Conference Proceedings (OSTI)

Laser plasma accelerators have produced high-quality electron beams with GeV energies from cm-scale devices and are being investigated as hyperspectral fs light sources producing THz to {gamma}-ray radiation and as drivers for future high-energy colliders. These applications require a high degree of stability, beam quality and tunability. Here we report on a technique to inject electrons into the accelerating field of a laser-driven plasma wave and coupling of this injector to a lower-density, separately tunable plasma for further acceleration. The technique relies on a single laser pulse powering a plasma structure with a tailored longitudinal density profile, to produce beams that can be tuned in the range of 100-400 MeV with percent-level stability, using laser pulses of less than 40 TW. The resulting device is a simple stand-alone accelerator or the front end for a multistage higher-energy accelerator.

Gonsalves, Anthony; Nakamura, Kei; Lin, Chen; Panasenko, Dmitriy; Shiraishi, Satomi; Sokollik, Thomas; Benedetti, Carlo; Schroeder, Carl; Geddes, Cameron; Tilborg, Jeroen van; Osterhoff, Jens; Esarey, Eric; Toth, Csaba; Leemans, Wim

2011-07-15T23:59:59.000Z

443

Ultra-low density microcellular polymer foam and method  

DOE Patents (OSTI)

An ultra-low density, microcellular open-celled polymer foam and a method for making such foam. A polymer is dissolved in a heated solution consisting essentially of at least one solvent for the dissolution of the polymer in the heated solution and the phase inversion of the dissolved polymer to a liquid gel upon sufficient cooling of the heated solution. The heated solution is contained in a containment means provided with a nucleating promoting means having a relatively rough surface formed of fixed nucleating sites. The heated solution is cooled for a period of time sufficient to form a liquid gel of the polymer by phase inversion. From the gel, a porous foam having a density of less than about 12.0 mg/cm.sup.3 and open porosity provided by well interconnected strut morphology is formed.

Simandl, Ronald F. (Farragut, TN); Brown, John D. (Harriman, TN)

1996-01-01T23:59:59.000Z

444

On the Density of PBH's in the Galactic Halo  

E-Print Network (OSTI)

Calculations of the rate of local Primordial Black Hole explosions often assume that the PBH's can be highly concentrated into galaxies, thereby weakening the Page-Hawking limit on the cosmological density of PBH's. But if the PBH's are concentrated by a factor exceeding $c/(H_\\circ R_\\circ) \\approx 4 \\times 10^5$, where $R_\\circ = 8.5$ kpc is the scale of the Milky Way, then the steady emission from the PBH's in the halo will produce an anisotropic high latitude diffuse gamma ray intensity larger than the observed anisotropy. This provides a limit on the rate-density of evaporating PBH's of $\\lesssim 0.4$~pc$^{-3}$yr$^{-1}$ which is more than 6 orders of magnitude lower than recent experimental limits. However, the weak observed anisotropic high latitude diffuse gamma ray intensity is consistent with the idea that the dark matter that closes the Universe is Planck mass remnants of evaporated black holes.

Edward L. Wright

1995-09-14T23:59:59.000Z

445

Special population planner, version 4.0.  

SciTech Connect

Emergencies happen every day. Many are caused by storms or auto accidents and can be planned for, if not predicted. Emergencies resulting from natural hazards often affect a large number of people, and planning for them can be difficult, since knowledge of the needs of the people involved is generally unavailable. Emergencies resulting from accidents at industrial and military facilities can also be large scale in nature if people must be evacuated or sheltered in place. Federal planning for large scale emergencies is the responsibility of the Federal Emergency Management Agency (FEMA), which provides assistance to various emergency management agencies at the national, state and local level. More information about FEMA is available at http://www.fema.gov/. The purpose of the Special Population Planner (SPP) is to help emergency planners address the needs of persons with special needs. The exact definition of 'special population' is a policy decision. Policymakers have included a variety of groups in this term, such as persons with disabilities, those who do not have vehicles with which to evacuate, children who are unattended at times (latchkey children), and many others. The SPP was developed initially for the Alabama Emergency Management Agency as part of its Chemical Stockpile Emergency Preparedness Program (CSEPP), which aids emergency planning and preparedness in communities surrounding military installations across the United States where chemical weapons are stored pending their destruction under federal law. Like that specialized application, this open-source version contains a set of specialized Geographic Information System (GIS) tools to facilitate emergency planning on behalf of persons with special needs, regardless of how the term is defined. While the original SPP system was developed for emergency planning relating to chemical hazards, it can be applied to other threats as well. It is apparent from Hurricane Katrina and other natural and man-made disasters that many of the problems posed by emergency planning for a chemical weapons agent release are shared by other hazards as well. The notion that emergency planning shares common functions underlies the decision by FEMA to include the Chemical Stockpile Emergency Preparedness Program (CSEPP) in its 'all-hazards' planning approach. The CSEPP's official planning guidance operationalizes this approach by suggesting that state and local CSEPP emergency plans 'should be appended to the existing all-hazards emergency plan.' The SPP is programmed as a set of tools within an ESRI ArcMap 9.1 project. ArcMap is a component of both ESRI ArcGIS 9.1 and ESRI ArcView 9.1, and it provides a rich GIS user interface for viewing spatial and tabular data, analyzing it, and producing output reports and maps. This GIS interface has been augmented with the SPP tools for a user interface that provides custom functionality for emergency planning. The system as released also includes some hypothetical example records for special needs populations, facilities, resources, control points and sirens sufficient for showing how the system would work with real information. A GIS database is included with some publicly available example layers. The SPP is designed to support emergency planners as they address emergency management issues, and includes capabilities that support the collection and importing of data, the review of data in a spatial context, and GIS tools for emergency planning. The SPP system allows for the identification and categorization of response zones to allow for multiple levels of preparedness. An Immediate Response Zone (IRZ) might be designated as the area 0 to 10 miles from a facility where the response would be the most urgent. SPP can support more than one set of planning zones to accommodate different types of emergencies or the different jurisdictions of emergency response organizations. These areas can be delineated by any number of criteria that make sense for the area. An area like New Orleans might designate response zones based on the depth above/below s

Kuiper, J.; Tanzman, E.; Metz, W.

2007-03-26T23:59:59.000Z

446

Line Density Indice as an alternative to MK process  

E-Print Network (OSTI)

73 broadband optical spectra of dwarf stars later than F0 have been obtained from the Nearby Stars Project website. The number of absorption lines is computed for each spectrum between 6000 and 6200 Angstrom. A correlation is found between the density of lines K$\\lambda$ and the spectral type. This method is independent of calibration process, does not require high resolution or high signal to noise data and does not make use of a large library of standard spectra.

M. Kuassivi

2009-12-31T23:59:59.000Z

447

Gravitational Energy-Momentum Density in Teleparallel Gravity  

E-Print Network (OSTI)

In the context of a gauge theory for the translation group, a conserved energy-momentum gauge current for the gravitational field is obtained. It is a true spacetime and gauge tensor, and transforms covariantly under global Lorentz transformations. By rewriting the gauge gravitational field equation in a purely spacetime form, it becomes the teleparallel equivalent of Einstein's equation, and the gauge current reduces to the M{\\o}ller's canonical energy-momentum density of the gravitational field.

V. C. de Andrade; L. C. T. Guillen; J. G. Pereira

2000-03-27T23:59:59.000Z

448

Fire Testing of High-Density Polyethylene Pipe  

Science Conference Proceedings (OSTI)

The results in this report are intended to demonstrate a method that can be used to protect high-density polyethylene (HDPE) piping located aboveground from postulated fire events. This includes protecting both pipe and pipe fittings (for example, elbows, tees, and valves) from the fire environmentincluding the heat transmitted from pipe supportsand preventing the fire environment from passing through building wall or floor penetrations. The report is intended to be complementary to other ongoing Electr...

2011-08-23T23:59:59.000Z

449

Method and apparatus for measuring lung density by Compton backscattering  

DOE Patents (OSTI)

The density of the lung of a patient suffering from pulmonary edema is monitored by irradiating the lung by a single collimated beam of monochromatic photons and measuring the energies of photons compton back-scattered from the lung by a single high-resolution, high-purity germanium detector. A compact system geometry and a unique data extraction scheme are utilized to minimize systematic errors due to the presence of the chestwall and multiple scattering. 11 figs., 1 tab.

Loo, B.W.; Goulding, F.S.

1988-03-11T23:59:59.000Z

450

Magneto-optical imaging of transport current densities in superconductors  

SciTech Connect

Direct imaging of the paths of transport currents in superconductors creates many new possibilities for exploring the basic features of vortex pinning mechanisms and for improving the performance of superconducting materials. A technique for imaging the path and magnitude of the transport current density flowing in superconductors is described. Results are given for a 37-filament BSCCO 2223 powder-in-tube wire, showing a highly inhomogeneous current path within the filaments.

Crabtree, G.W.; Welp, U.; Gunter, D.O.; Zhong, W.; Balachandran, U. [Argonne National Lab., IL (United States); Haldar, P.; Sokolowski, R.S. [Intermagnetics General Corp., Latham, NY (United States); Vlasko-Vlasov, V.K.; Nikitenko, V.I. [Inst. for Solid State Physics, Moscow (Russian Federation)

1995-12-31T23:59:59.000Z

451

The Nuclear Equation of State at high densities  

E-Print Network (OSTI)

Ab inito calculations for the nuclear many-body problem make predictions for the density and isospin dependence of the nuclear equation-of-state (EOS) far away from the saturation point of nuclear matter. I compare predictions from microscopic and phenomenological approaches. Constraints on the EOS derived from heavy ion reactions, in particular from subthreshold kaon production, as well as constraints from neutron stars are discussed.

Christian Fuchs

2006-10-10T23:59:59.000Z

452

The elusive minimum viable population size for white sturgeon  

SciTech Connect

Biological conservation of sturgeon populations is a concern for many species. Those responsible for managing the white sturgeon (Acipenser transmontanus) and similar species are interested in identifying extinction thresholds to avoid. Two thresholds that exist in theory are the minimum viable population size (MVP) and minimum amount of suitable habitat. In this paper, we present both model and empirical estimates of these thresholds. We modified a population viability analysis (PVA) model for white sturgeon to include two new Allee mechanisms. Despite this, PVA-based MVP estimates were unrealistically low compared with empirical estimates unless opportunities for spawning were assumed to be less frequent. PVA results revealed a trade-off between MVP and habitat thresholds; smaller populations persisted in longer river segments and vice versa. Our empirical analyses suggested (1) a MVP range based on population trends from 1,194 to 27,700 individuals, and (2) a MVP estimate of 4,000 individuals based on recruitment. Long-term historical population surveys are needed for more populations to pinpoint an MVP based on trends, whereas the available data were sufficient to estimate MVP based on recruitment. Beyond the MVP, we developed a hierarchical model for population status based on empirical data. Metapopulation support was the most important predictor of population health, followed by the length of free-flowing habitat, with habitat thresholds at 26 and 150 km. Together, these results suggest that habitat and connectivity are important determinants of population status that likely influence the site-specific MVP thresholds.

Jager, Yetta [ORNL; Lepla, Ken B. [Idaho Power Company; Van Winkle, Webb [Van Windle Environmental Consulting; James, Mr Brad [Washington Department of Fish and Wildlife; McAdam, Dr Steve [University of British Columbia, Vancouver

2010-01-01T23:59:59.000Z

453

File:Air Density Lab.pdf | Open Energy Information  

Open Energy Info (EERE)

Air Density Lab.pdf Air Density Lab.pdf Jump to: navigation, search File File history File usage Metadata File:Air Density Lab.pdf Size of this preview: 463 × 599 pixels. Other resolution: 464 × 600 pixels. Go to page 1 2 3 4 Go! next page → next page → Full resolution ‎(1,275 × 1,650 pixels, file size: 240 KB, MIME type: application/pdf, 4 pages) File history Click on a date/time to view the file as it appeared at that time. Date/Time Thumbnail Dimensions User Comment current 09:36, 3 January 2014 Thumbnail for version as of 09:36, 3 January 2014 1,275 × 1,650, 4 pages (240 KB) Foteri (Talk | contribs) Category:Wind for Schools Portal CurriculaCategory:Wind for Schools High School Curricula You cannot overwrite this file. Edit this file using an external application (See the setup

454

SURFACE SYMMETRY ENERGY OF NUCLEAR ENERGY DENSITY FUNCTIONALS  

Science Conference Proceedings (OSTI)

We study the bulk deformation properties of the Skyrme nuclear energy density functionals. Following simple arguments based on the leptodermous expansion and liquid drop model, we apply the nuclear density functional theory to assess the role of the surface symmetry energy in nuclei. To this end, we validate the commonly used functional parametrizations against the data on excitation energies of superdeformed band-heads in Hg and Pb isotopes, and fission isomers in actinide nuclei. After subtracting shell effects, the results of our self-consistent calculations are consistent with macroscopic arguments and indicate that experimental data on strongly deformed configurations in neutron-rich nuclei are essential for optimizing future nuclear energy density functionals. The resulting survey provides a useful benchmark for further theoretical improvements. Unlike in nuclei close to the stability valley, whose macroscopic deformability hangs on the balance of surface and Coulomb terms, the deformability of neutron-rich nuclei strongly depends on the surface-symmetry energy; hence, its proper determination is crucial for the stability of deformed phases of the neutron-rich matter and description of fission rates for r-process nucleosynthesis.

Nikolov, N; Schunck, N; Nazarewicz, W; Bender, M; Pei, J

2010-12-20T23:59:59.000Z

455

Density fluctuation measurements via beam emission spectroscopy (invited)  

SciTech Connect

Previous studies of plasma microturbulence have indicated that the fluctuation power scales with radial wave number, {ital k}{sub {perpendicular}} , like {ital k}{sub {perpendicular}}{sup {minus}2}{r arrow}{ital k}{sub {perpendicular}}{sup {minus}3.5} for {ital k}{sub {perpendicular}} {ge}2 cm{sup {minus}1}. This implies that low {ital k} fluctuations may dominate the spectrum. Beam emission spectroscopy (BES) has been developed to provide spatially localized measurements of density fluctuations in this low {ital k} region of the spectrum ({ital k}{sub {perpendicular}} {le}2 cm{sup {minus}1}). A 20-channel system has been installed on TFTR which images one of the heating neutral beams (via fiber optics) onto a set of photoconductive photodiode detectors. Fluctuations in the fluorescent {ital D}{sub {alpha}} emission from the beam can be related to the local plasma density fluctuations via a model of the atomic excitation processes. The analysis of BES data utilizes many of the standard statistical analysis techniques such as power spectra, coherency and cross phase, and correlation analysis which are also used in the analysis of, for example, Langmuir probe data. In the case of BES however, these techniques require some special modifications to account for systematic effects such as photon statistics and fluctuations in the neutral beam density induced by the strong fluctuations near the plasma edge.

Durst, R.D.; Fonck, R.J.; Cosby, G.; Evensen, H. (University of Wisconsin/Madison, Madison, Wisconsin 53706 (United States)); Paul, S.F. (Princeton Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08541 (United States))

1992-10-01T23:59:59.000Z

456

Cerenkov Photon Density Fluctuations in Extensive Air Showers  

E-Print Network (OSTI)

The details of Cerenkov light produced by a gamma ray or a cosmic ray incident at the top of the atmosphere is best studied through systematic simulations of the extensive air showers. Recently such studies have become all the more important in view of the various techniques resulting from such studies, to distinguish gamma ray initiated showers from those generated by much more abundant hadronic component of cosmic rays. We have carried out here such systematic simulation studies using CORSIKA package in order to understand the Cerenkov photon density fluctuations for 5 different energies at various core distances both for gamma ray and proton primaries incident vertically at the top of the atmosphere. Such a systematic comparison of shower to shower density fluctuations for gamma ray and proton primaries is carried out for the first time here. It is found that the density fluctuations are significantly non-Poissonian. Such fluctuations are much more pronounced in the proton primaries than gamma ray primaries at all energies. The processes that contribute significantly to the observed fluctuations have been identified. It has been found that significant contribution to fluctuations comes from photons emitted after shower maximum. The electron number fluctuations and correlated emission of Cerenkov photons are mainly responsible for the observed fluctuations.

V. R. Chitnis; P. N. Bhat

1998-02-14T23:59:59.000Z

457

Coded modulation with Low Density Parity Check codes  

E-Print Network (OSTI)

This thesis proposes the design of Low Density Parity Check (LDPC) codes for cases where coded modulation is used. We design these codes by extending the idea of Density Evolution (DE) that has been introduced as a powerful tool to analyze LDPC codes. We first discuss methods by which we can design these codes for higher order constellations like 8 Phase Shift Keying (PSK) and 16 Quadrature Amplitude Modulation (QAM). We present simulation results that are within 0.22 dB and 0.4 dB within the constrained capacity of 8 PSK and 16 QAM constellations respectively in an Additive White Gaussian Noise (AWGN) channel. In the second part, we investigate serial concatenation of LDPC codes and minimum shift keying (MSK) with iterative decoding. We show that the design of LDPC codes is crucially dependent on the realization of the MSK modulator. For MSK modulators with non-recursive continuous phase encoders (CPEs), optimal codes for BPSK are optimal whereas for MSK modulators with recursive CPEs the BPSK codes are not optimal. We show that for non-recursive CPEs, iterative demodulation and decoding is not required even though the CPE has memory. However, iterative demodulation is essential for recursive CPEs. For recursive CPEs, we design LDPC codes using density evolution and differential evolution by looking at the graph structure of the CPE and considering message passing between both these codes. The resulting codes provide significantly improved performance over the existing codes.

Narayanaswami, Ravi

2001-01-01T23:59:59.000Z

458

BARS REJUVENATING BULGES? EVIDENCE FROM STELLAR POPULATION ANALYSIS  

SciTech Connect

We obtained stellar ages and metallicities via spectrum fitting for a sample of 575 bulges with spectra available from the Sloan Digital Sky Survey. The structural properties of the galaxies have been studied in detail in 2009 by Gadotti and the sample contains 251 bulges in galaxies with bars. Using the whole sample, where galaxy stellar mass distributions for barred and unbarred galaxies are similar, we find that bulges in barred and unbarred galaxies occupy similar loci in the age versus metallicity plane. However, the distribution of bulge ages in barred galaxies shows an excess of populations younger than {approx}4 Gyr, when compared to bulges in unbarred galaxies. Kolmogorov-Smirnov statistics confirm that the age distributions are different with a significance of 99.94%. If we select sub-samples for which the bulge stellar mass distributions are similar for barred and unbarred galaxies, this excess vanishes for galaxies with bulge mass log M < 10.1 M{sub Sun }, while for more massive galaxies we find a bimodal bulge age distribution for barred galaxies only, corresponding to two normal distributions with mean ages of 10.4 and 4.7 Gyr. We also find twice as much active galactic nuclei among barred galaxies, as compared to unbarred galaxies, for low-mass bulges. By combining a large sample of high-quality data with sophisticated image and spectral analysis, we are able to find evidence that the presence of bars affects the mean stellar ages of bulges. This lends strong support to models in which bars trigger star formation activity in the centers of galaxies.

Coelho, P. [Nucleo de Astrofisica Teorica, Universidade Cruzeiro do Sul, R. Galvao Bueno 868, Liberdade 01506-000, Sao Paulo (Brazil); Gadotti, D. A., E-mail: paula.coelho@cruzeirodosul.edu.br, E-mail: dgadotti@eso.org [European Southern Observatory, Casilla 19001, Santiago 19 (Chile)

2011-12-10T23:59:59.000Z

459

Reference material RM 7811-7 for identification cards with high coercivity high density magnetic stripes  

E-Print Network (OSTI)

Reference material RM 7811-7 for identification cards with high coercivity high density magnetic stripes

Albrecht, M

2003-01-01T23:59:59.000Z

460

High Energy Density Physics and Exotic Acceleration Schemes  

Science Conference Proceedings (OSTI)

The High Energy Density and Exotic Acceleration working group took as our goal to reach beyond the community of plasma accelerator research with its applications to high energy physics, to promote exchange with other disciplines which are challenged by related and demanding beam physics issues. The scope of the group was to cover particle acceleration and beam transport that, unlike other groups at AAC, are not mediated by plasmas or by electromagnetic structures. At this Workshop, we saw an impressive advancement from years past in the area of Vacuum Acceleration, for example with the LEAP experiment at Stanford. And we saw an influx of exciting new beam physics topics involving particle propagation inside of solid-density plasmas or at extremely high charge density, particularly in the areas of laser acceleration of ions, and extreme beams for fusion energy research, including Heavy-ion Inertial Fusion beam physics. One example of the importance and extreme nature of beam physics in HED research is the requirement in the Fast Ignitor scheme of inertial fusion to heat a compressed DT fusion pellet to keV temperatures by injection of laser-driven electron or ion beams of giga-Amp current. Even in modest experiments presently being performed on the laser-acceleration of ions from solids, mega-amp currents of MeV electrons must be transported through solid foils, requiring almost complete return current neutralization, and giving rise to a wide variety of beam-plasma instabilities. As keynote talks our group promoted Ion Acceleration (plenary talk by A. MacKinnon), which historically has grown out of inertial fusion research, and HIF Accelerator Research (invited talk by A. Friedman), which will require impressive advancements in space-charge-limited ion beam physics and in understanding the generation and transport of neutralized ion beams. A unifying aspect of High Energy Density applications was the physics of particle beams inside of solids, which is proving to be a very important field for diverse applications such as muon cooling, fusion energy research, and ultra-bright particle and radiation generation with high intensity lasers. We had several talks on these and other subjects, and many joint sessions with the Computational group, the EM Structures group, and the Beam Generation group. We summarize our groups' work in the following categories: vacuum acceleration schemes; ion acceleration; particle transport in solids; and applications to high energy density phenomena.

Cowan, T.; /General Atomics, San Diego; Colby, E.; /SLAC

2005-09-27T23:59:59.000Z

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461

Cooperative spin decoherence and population transfer  

E-Print Network (OSTI)

An ensemble of multilevel atoms is a good candidate for a quantum information storage device. The information is encrypted in the collective ground state atomic coherence, which, in the absence of external excitation, is decoupled from the vacuum and therefore decoherence free. However, in the process of manipulation of atoms with light pulses (writing, reading), one inadvertently introduces a coupling to the environment, i.e. a source of decoherence. The dissipation process is often treated as an independent process for each atom in the ensemble, an approach which fails at large atomic optical depths where cooperative effects must be taken into account. In this paper, the cooperative behavior of spin decoherence and population transfer for a system of two, driven multilevel-atoms is studied. Not surprisingly, an enhancement in the decoherence rate is found, when the atoms are separated by a distance that is small compared to an optical wavelength; however, it is found that this rate increases even further for somewhat larger separations for atoms aligned along the direction of the driving field's propagation vector. A treatment of the cooperative modification of optical pumping rates and an effect of polarization swapping between atoms is also discussed, lending additional insight into the origin of the collective decay.

C. Genes; P. R. Berman

2006-01-30T23:59:59.000Z

462

Magnetic Fields in Population III Star Formation  

DOE Green Energy (OSTI)

We study the buildup of magnetic fields during the formation of Population III star-forming regions, by conducting cosmological simulations from realistic initial conditions and varying the Jeans resolution. To investigate this in detail, we start simulations from identical initial conditions, mandating 16, 32 and 64 zones per Jeans length, and studied the variation in their magnetic field amplification. We find that, while compression results in some amplification, turbulent velocity fluctuations driven by the collapse can further amplify an initially weak seed field via dynamo action, provided there is sufficient numerical resolution to capture vortical motions (we find this requirement to be 64 zones per Jeans length, slightly larger than, but consistent with previous work run with more idealized collapse scenarios). We explore saturation of amplification of the magnetic field, which could potentially become dynamically important in subsequent, fully-resolved calculations. We have also identified a relatively surprising phenomena that is purely hydrodynamic: the higher-resolved simulations possess substantially different characteristics, including higher infall-velocity, increased temperatures inside 1000 AU, and decreased molecular hydrogen content in the innermost region. Furthermore, we find that disk formation is suppressed in higher-resolution calculations, at least at the times that we can follow the calculation. We discuss the effect this may have on the buildup of disks over the accretion history of the first clump to form as well as the potential for gravitational instabilities to develop and induce fragmentation.

Turk, Matthew J.; Oishi, Jeffrey S.; Abel, Tom; Bryan, Greg

2012-02-22T23:59:59.000Z

463

HOUSEHOLD AND STRUCTURAL INSECTS Residual Activity and Population Effects of Noviflumuron for German  

E-Print Network (OSTI)

collected by spraying a mixture of honey and water to attract bee hosts, which in turn attracted parasitic phorid flies. In earlier collections we sprayed honey on a white sheet, termed a bee screen (Brown, 2001), but later collections were made directly from honey-sprayed undergrowth vegetation. SYSTEMATICS PHYLOGENETIC

Wang, Changlu