Science.gov

Sample records for actual energy density

  1. High Energy Density Capacitors

    SciTech Connect

    2010-07-01

    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.

  2. High Energy Density Microwaves

    SciTech Connect

    Phillips, R.M.

    1999-04-01

    These proceedings represent papers presented at the RF98 Workshop entitled `High Energy Density Microwaves` held in California in October, 1998. The topics discussed were predominantly accelerator{minus}related. The Workshop dealt, for the most part, with the generation and control of electron beams, the amplification of RF signals, the design of mode converters, and the effect of very high RF field gradients. This Workshop was designed to address the concerns of the microwave tube industry worldwide, the plasma physicists who deal with very high beam currents and gigawatts of RF power, and researchers in accelerator centers around the world. Papers were presented on multibeam klystrons, gyrotron development, plasmas in microwave tubes, RF breakdown, and alternatives to conventional linear coliders at 1 TeV and above. The Workshop was partially sponsored by the US Department of Energy. There were 46 papers presented at the conference,out of which 19 have been abstracted for the Energy,Science and Technology database.(AIP)

  3. Nuclear Energy Density Optimization

    SciTech Connect

    Kortelainen, Erno M; Lesinski, Thomas; More, J.; Nazarewicz, W.; Sarich, J.; Schunck, N.; Stoitsov, M. V.; Wild, S.

    2010-01-01

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

  4. Density-dependent covariant energy density functionals

    SciTech Connect

    Lalazissis, G. A.

    2012-10-20

    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.

  5. High energy density electrochemical cell

    NASA Technical Reports Server (NTRS)

    Byrne, J. J.; Williams, D. L.

    1970-01-01

    Primary cell has an anode of lithium, a cathode containing dihaloisocyanuric acid, and a nonaqueous electrolyte comprised of a solution of lithium perchlorate in methyl formate. It produces an energy density of 213 watt hrs/lb and can achieve a high current density.

  6. Characterizing the response of galloping energy harvesters using actual wind statistics

    NASA Astrophysics Data System (ADS)

    Daqaq, Mohammed F.

    2015-11-01

    In this paper, we incorporate actual wind statistics into the response of galloping energy harvesters and shed light onto the influence of the wind probability distribution on the average power as compared to the deterministic scenario. Specifically, we obtain an expression for the average output power of the harvester as a function of the wind statistical averages, which are, in turn, obtained by fitting wind data using a Weibull Probability Density Function (PDF). The resulting expression is then used to demonstrate that knowledge of the actual PDF is essential for correct power predictions as well as for accurate electric load optimization. We discuss the influence of the wind direction on the average output power and show that the direction of the prevailing wind is not necessarily the ideal direction to maximize the average power.

  7. Phenomenological Relativistic Energy Density Functionals

    SciTech Connect

    Lalazissis, G. A.; Kartzikos, S.; Niksic, T.; Paar, N.; Vretenar, D.; Ring, P.

    2009-08-26

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

  8. Actual and Estimated Energy Savings Comparison for Deep Energy Retrofits in the Pacific Northwest

    SciTech Connect

    Blanchard, Jeremy; Widder, Sarah H.; Giever, Elisabeth L.; Baechler, Michael C.

    2012-10-01

    Seven homes from the Pacific Northwest were selected to evaluate the differences between estimated and actual energy savings achieved from deep energy retrofits. The energy savings resulting from these retrofits were estimated, using energy modeling software, to save at least 30% on a whole-house basis. The modeled pre-retrofit energy use was trued against monthly utility bills. After the retrofits were completed, each of the homes was extensively monitored, with the exception of one home which was monitored pre-retrofit. This work is being conducted by Pacific Northwest National Laboratory (PNNL) for the U.S. Department of Energy Building Technologies Program as part of the Building America Program. This work found many discrepancies between actual and estimated energy savings and identified the potential causes for the discrepancies. The differences between actual energy use and modeled energy use also suggest improvements to improve model accuracy. The difference between monthly whole-house actual and estimated energy savings ranged from 75% more energy saved than predicted by the model to 16% less energy saved for all the monitored homes. Similarly, the annual energy savings difference was between 36% and -14%, which was estimated based on existing monitored savings because an entire year of data is not available. Thus, on average, for all six monitored homes the actual energy use is consistently less than estimates, indicating home owners are saving more energy than estimated. The average estimated savings for the eight month monitoring period is 43%, compared to an estimated savings average of 31%. Though this average difference is only 12%, the range of inaccuracies found for specific end-uses is far greater and are the values used to directly estimate energy savings from specific retrofits. Specifically, the monthly post-retrofit energy use differences for specific end-uses (i.e., heating, cooling, hot water, appliances, etc.) ranged from 131% under

  9. High Energy Density Electrolytic Capacitor

    NASA Technical Reports Server (NTRS)

    Evans, David A.

    1996-01-01

    A new type of electrolytic capacitor which combines an electrolytic capacitor anode with an electrochemical capacitor cathode was developed. The resulting capacitor has a four time higher energy density than standard electrolytic capacitors, with comparable electric performance. The prototype, a 480 microFarad, 200 V device, has an energy density exceeding 4 J/cc. Now a 680 microFarad 50 V, MIL-style all tantalum device has been constructed and is undergoing qualification testing. Pending a favorable outcome, work will begin on other ratings. The potential for commercially significant development exists in applying this technology to aluminum-based electrolytic capacitors. It is possible to at least double the energy density of aluminum electrolytics, while using existing manufacturing methods, and without adding material expense. Data presented include electrical characteristics and performance measurements of the 200 V and 50 V hybrid capacitors and results from ongoing qualification testing of the MIL-style tantalum capacitors.

  10. High energy density electrolytic capacitor

    NASA Technical Reports Server (NTRS)

    Evans, David A.

    1995-01-01

    Recently a new type of electrolytic capacitor was developed. This capacitor, the Evans Hybrid, combines an electrolytic capacitor anode with an electrochemical capacitors cathode. The resulting capacitor has four times the energy density of other electrolytic capacitors, with comparable electrical performance. The prototype, a 480 micro F, 200 V device, had an energy density exceeding 4 J/cc. Now, a 680 micro F, 50 V, MIL-style all tantalum device has been constructed and is undergoing qualification testing. Pending a favorable outcome, work will begin on other ratings. Potential for commercially significant development exists in applying this technology to aluminum-based electrolytic capacitors. It is possible to at least double the energy density of aluminum electrolytics, while using existing manufacturing methods, and without adding material expense. Data presented include electrical characteristics and performance measurements of the 200 V and 50 V Hybrid capacitors and results of ongolng qualification status of the MJL-style tantalum.

  11. Improved energy density homopolar generator

    NASA Astrophysics Data System (ADS)

    Walls, W. A.; Weldon, Wm. F.; Driga, M. D.; Manifold, S. M.; Woodson, H. H.

    1986-11-01

    The preliminary design of a self excited, air-core (SEAC) homopolar generator (HPG) which stores about 250 MJ inertially and is capable of delivering 3.2 MA current pulses is presented. In aiming for maximum energy density in an HPG and inductor power supply for electromagnetic (EM) accelerators, the improved energy density (IED) machine uses its self-excited field coils as energy storage inductors and a lightweight graphite reinforced flywheel for inertial energy storage. Weighing approximately 5,000 kg, the design represents a twenty-fold increase in mass energy density over the state of the art and addresses the problem of trapping flux in the rotor during discharge by separating the voltage generating and energy storage functions. Voltage is generated across a squirrel-cage rotor armature by an opposed pair of five-turn cryogenically cooled field coils/inductors. Inertial energy is stored in a graphite-reinforced epoxy flywheel which will operate at a maximum tip speed of 1,100 m/s. The machine is expected to develop about 500 V at half speed while charging the coils to 130 MJ at 3.2 MA. Peak output voltage during discharge of coils will be roughly 10 kV.

  12. Calibrated energy simulations of potential energy savings in actual retail buildings

    NASA Astrophysics Data System (ADS)

    Alhafi, Zuhaira

    Retail stores are commercial buildings with high energy consumption due to their typically large volumes and long hours of operation. This dissertation assesses heating, ventilating and air conditioning saving strategies based on energy simulations with input parameters from actual retail buildings. The dissertation hypothesis is that "Retail store buildings will save a significant amount of energy by (1) modifying ventilation rates, and/or (2) resetting set point temperatures. These strategies have shown to be beneficial in previous studies. As presented in the literature review, potential energy savings ranged from 0.5% to 30% without compromising indoor thermal comfort and indoor air quality. The retail store buildings can be ventilated at rates significantly lower than rates called for in the ASHRAE Standard 62.1-2010 while maintaining acceptable indoor air quality. Therefore, two dissertation objectives are addressed: (1) Investigate opportunities to reduce ventilation rates that do not compromise indoor air quality in retail stores located in Central Pennsylvania, (2) Investigate opportunities to increase (in summer) and decrease (in winter) set point temperatures that do not compromise thermal comfort. This study conducted experimental measurements of ventilation rates required to maintain acceptable air quality and indoor environmental conditions requirements for two retail stores using ASHRAE Standard 62.1_2012. More specifically, among other parameters, occupancy density, indoor and outdoor pollutant concentrations, and indoor temperatures were measured continuously for one week interval. One of these retail stores were tested four times for a yearlong time period. Pollutants monitored were formaldehyde, carbon dioxide, particle size distributions and concentrations, as well as total volatile organic compounds. As a part of the base protocol, the number of occupants in each store was hourly counted during the test, and the results reveal that the occupant

  13. High-Energy-Density Capacitors

    NASA Technical Reports Server (NTRS)

    Slenes, Kirk

    2003-01-01

    Capacitors capable of storing energy at high densities are being developed for use in pulse-power circuits in such diverse systems as defibrillators, particle- beam accelerators, microwave sources, and weapons. Like typical previously developed energy-storage capacitors, these capacitors are made from pairs of metal/solid-dielectric laminated sheets that are wound and pressed into compact shapes to fit into cans, which are then filled with dielectric fluids. Indeed, these capacitors can be fabricated largely by conventional fabrication techniques. The main features that distinguish these capacitors from previously developed ones are improvements in (1) the selection of laminate materials, (2) the fabrication of the laminated sheets from these materials, and (3) the selection of dielectric fluids. In simplest terms, a high-performance laminated sheet of the type used in these capacitors is made by casting a dielectric polymer onto a sheet of aluminized kraft paper. The dielectric polymer is a siloxane polymer that has been modified with polar pendant groups to increase its permittivity and dielectric strength. Potentially, this polymer is capable of withstanding an energy density of 7.5 J/cm3, which is four times that of the previous state-of-the-art-capacitor dielectric film material. However, the full potential of this polymer cannot be realized at present because (1) at thicknesses needed for optimum performance (.8.0 m), the mechanical strength of a film of this polymer is insufficient for incorporation into a wound capacitor and (2) at greater thickness, the achievable energy density decreases because of a logarithmic decrease in dielectric strength with increasing thickness. The aluminized kraft paper provides the mechanical strength needed for processing of the laminate and fabrication of the capacitor, and the aluminum film serves as an electrode layer. Because part of the thickness of the dielectric is not occupied by the modified siloxane polymer, the

  14. High Energy Density Laboratory Astrophysics

    SciTech Connect

    Remington, B A

    2004-11-11

    High-energy-density (HED) physics refers broadly to the study of macroscopic collections of matter under extreme conditions of temperature and density. The experimental facilities most widely used for these studies are high-power lasers and magnetic-pinch generators. The HED physics pursued on these facilities is still in its infancy, yet new regimes of experimental science are emerging. Examples from astrophysics include work relevant to planetary interiors, supernovae, astrophysical jets, and accreting compact objects (such as neutron stars and black holes). In this paper, we will review a selection of recent results in this new field of HED laboratory astrophysics and provide a brief look ahead to the coming decade.

  15. Actual information storage with a recording density of 4 Tbit/in.2 in a ferroelectric recording medium

    NASA Astrophysics Data System (ADS)

    Tanaka, Kenkou; Cho, Yasuo

    2010-08-01

    A new method to achieve real information recording with a density above 1 Tbit/in.2 in ferroelectric data storage systems is proposed. In this system, data bits were written in the form of the polarization direction, and the data were read by scanning nonlinear dielectric microscopy technique. The domain-switching characteristics of the virgin and inversely prepolarized media were compared, and the conditions of the pulse voltage for writing were optimized. As a result, actual data containing 64×64 bits were recorded at an areal density of 4 Tbit/in.2. The bit error rate was evaluated to be 1.2×10-2.

  16. The role of energy density.

    PubMed

    Drewnowski, Adam

    2003-02-01

    Dietary energy density (ED) appears to have a major influence on the regulation of food intake and body weight. If people consume a fixed weight of food each day, then high-ED diets should be associated with high energy intakes and with overweight. In contrast, low-ED diets should result in lower daily energy intakes and therefore weight loss. For this approach to work, low-ED foods must be as palatable as high-ED foods and, calorie for calorie, have a greater satiating power. Each of those assumptions is debatable. Dietary ED depends chiefly on the water content of foods. As a rule, high-ED foods are more palatable but less satiating, whereas low-ED foods are more satiating but less palatable. Consumer preferences for high-ED foods can be explained in terms of good taste, low cost, and convenience. Low-ED foods, such as fresh produce, provide less energy per unit cost than do high-ED foods, which often contain added sugars and fats. Poverty and obesity may well be linked through the habitual consumption of a low-cost, high-ED diet. PMID:12733741

  17. Oxides having high energy densities

    DOEpatents

    Ceder, Gerbrand; Kang, Kisuk

    2013-09-10

    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.

  18. Comparison of actual and predicted energy savings in Minnesota gas-heated single-family homes

    SciTech Connect

    Hirst, E.; Goeltz, R.

    1984-03-01

    Data available from a recent evaluation of a home energy audit program in Minnesota are sufficient to allow analysis of the actual energy savings achieved in audited homes and of the relationship between actual and predicted savings. The program, operated by Northern States Power in much of the southern half of the state, is part of Minnesota's version of the federal Residential Conservation Service. NSP conducted almost 12 thousand RCS audits between April 1981 (when the progam began) and the end of 1982. The data analyzed here, available for 346 homes that obtained an NSP energy audit, include monthly natural gas bills from October 1980 through April 1983; heating degree day data matched to the gas bills; energy audit reports; and information on household demographics, structure characteristics, and recent conservation actions from mail and telephone surveys. The actual reduction in weather-adjusted natural gas use between years 1 and 3 averaged 19 MBtu across these homes (11% of preprogram consumption); the median value of the saving was 16 MBtu/year. The variation in actual saving is quite large: gas consumption increased in almost 20% of the homes, while gas consumption decreased by more than 50 MBtu/year in more than 10% of the homes. These households reported an average expenditure of almost $1600 for the retrofit measures installed in their homes; the variation in retrofit cost, while large, was not as great as the variation in actual natural gas savings.

  19. Investigating the discrepancy between the predicted and actual energy performance of buildings

    NASA Astrophysics Data System (ADS)

    Demanuele, Christine

    The threat of climate change has increased the demand for energy efficiency in buildings, with various stakeholders requesting more accurate predictions of energy consumption, and energy consultants coming under increased pressure to guarantee the energy performance of buildings. This study aims to investigate the factors causing the discrepancy which currently exists between the predicted and actual energy performance of buildings, which will lead to a deeper understanding of this discrepancy and, ultimately, more accurate energy predictions. As part of this study, a non-domestic building in London was modelled and monitored, so as to identify the main contributors to the discrepancy between the predicted and actual energy consumption. In addition, sensitivity analysis was carried out on a number of input variables to establish the set of influential parameters, and to determine whether using such techniques would successfully predict the range in which building energy consumption is likely to fall. The results show that the uncertainty calculated from differential sensitivity analysis encompasses the actual energy performance of the building. The most variable and influential parameters are those which are controlled by occupants, therefore it is paramount that management and occupants are well-informed about the building operation for energy targets to be achieved. Although the sensitivity analysis methods employed are impractical for commercial use, it is possible to develop simpler methods, encompassing all stages of building design and operation, which would decrease the discrepancy between the actual and predicted energy performance of buildings. Such techniques would be invaluable to energy consultants, for whom the cost resting on uncertainties in predictions is substantial due to more demanding clients and fines liable to be paid if energy predictions go wrong. A better understanding of the discrepancy, together with more accurate predictions, would

  20. An insight into actual energy use and its drivers in high-performance buildings

    SciTech Connect

    Li, Cheng; Hong, Tianzhen; Yan, Da

    2014-07-12

    Using portfolio analysis and individual detailed case studies, we studied the energy performance and drivers of energy use in 51 high-performance office buildings in the U.S., Europe, China, and other parts of Asia. Portfolio analyses revealed that actual site energy use intensity (EUI) of the study buildings varied by a factor of as much as 11, indicating significant variation in real energy use in HPBs worldwide. Nearly half of the buildings did not meet the American Society of Heating, Refrigerating, and Air Conditioning Engineers (ASHRAE) Standard 90.1-2004 energy target, raising questions about whether a building’s certification as high performing accurately indicates that a building is energy efficient and suggesting that improvement in the design and operation of HPBs is needed to realize their energy-saving potential. We studied the influence of climate, building size, and building technologies on building energy performance and found that although all are important, none are decisive factors in building energy use. EUIs were widely scattered in all climate zones. There was a trend toward low energy use in small buildings, but the correlation was not absolute; some small HPBs exhibited high energy use, and some large HPBs exhibited low energy use. We were unable to identify a set of efficient technologies that correlated directly to low EUIs. In two case studies, we investigated the influence of occupant behavior as well as operation and maintenance on energy performance and found that both play significant roles in realizing energy savings. We conclude that no single factor determines the actual energy performance of HPBs, and adding multiple efficient technologies does not necessarily improve building energy performance; therefore, an integrated design approach that takes account of climate, technology, occupant behavior, and operations and maintenance practices should be implemented to maximize energy savings in HPBs. As a result, these findings are

  1. An insight into actual energy use and its drivers in high-performance buildings

    DOE PAGESBeta

    Li, Cheng; Hong, Tianzhen; Yan, Da

    2014-07-12

    Using portfolio analysis and individual detailed case studies, we studied the energy performance and drivers of energy use in 51 high-performance office buildings in the U.S., Europe, China, and other parts of Asia. Portfolio analyses revealed that actual site energy use intensity (EUI) of the study buildings varied by a factor of as much as 11, indicating significant variation in real energy use in HPBs worldwide. Nearly half of the buildings did not meet the American Society of Heating, Refrigerating, and Air Conditioning Engineers (ASHRAE) Standard 90.1-2004 energy target, raising questions about whether a building’s certification as high performing accuratelymore » indicates that a building is energy efficient and suggesting that improvement in the design and operation of HPBs is needed to realize their energy-saving potential. We studied the influence of climate, building size, and building technologies on building energy performance and found that although all are important, none are decisive factors in building energy use. EUIs were widely scattered in all climate zones. There was a trend toward low energy use in small buildings, but the correlation was not absolute; some small HPBs exhibited high energy use, and some large HPBs exhibited low energy use. We were unable to identify a set of efficient technologies that correlated directly to low EUIs. In two case studies, we investigated the influence of occupant behavior as well as operation and maintenance on energy performance and found that both play significant roles in realizing energy savings. We conclude that no single factor determines the actual energy performance of HPBs, and adding multiple efficient technologies does not necessarily improve building energy performance; therefore, an integrated design approach that takes account of climate, technology, occupant behavior, and operations and maintenance practices should be implemented to maximize energy savings in HPBs. As a result, these

  2. Study on Tire-attached Energy Harvester for Low-speed Actual Vehicle Driving

    NASA Astrophysics Data System (ADS)

    Zhang, Y.; Zheng, R.; Kaizuka, T.; Su, D.; Nakano, K.

    2015-12-01

    This study reports a tire-attached energy harvester, in which a cantilever beam pasted piezoelectric film and magnets with the same polarity are fabricated as a bistable vibrating system, for low-speed actual-vehicle driving. As the wheel rotates, the energy harvester is subjected to the noise produced from the interaction between the paved road and the rotating tire, and tangentially gravitational force as a periodic input can be applied to achieve the occurrence of stochastic resonance. Stochastic resonance can significantly stimulate the response of the bistable vibrating system, and therefore enhance the energy harvesting efficiency.

  3. Quantum kinetic energy densities: An operational approach

    SciTech Connect

    Muga, J.G.; Seidel, D.; Hegerfeldt, G.C.

    2005-04-15

    We propose and investigate a procedure to measure, at least in principle, a positive quantum version of the local kinetic energy density. This procedure is based, under certain idealized limits, on the detection rate of photons emitted by moving atoms which are excited by a localized laser beam. The same type of experiment, but in different limits, can also provide other non-positive-definite versions of the kinetic energy density. A connection with quantum arrival time distributions is discussed.

  4. Universal Nuclear Energy Density Functional

    SciTech Connect

    Carlson, Joseph; Furnstahl, Richard; Horoi, Mihai; Lusk, Rusty; Nazarewicz, Witold; Ng, Esmond; Thompson, Ian; Vary, James

    2012-12-01

    An understanding of the properties of atomic nuclei is crucial for a complete nuclear theory, for element formation, for properties of stars, and for present and future energy and defense applications. During the period of Dec. 1 2006 – Jun. 30, 2012, the UNEDF collaboration carried out a comprehensive study of all nuclei, based on the most accurate knowledge of the strong nuclear interaction, the most reliable theoretical approaches, the most advanced algorithms, and extensive computational resources, with a view towards scaling to the petaflop platforms and beyond. Until recently such an undertaking was hard to imagine, and even at the present time such an ambitious endeavor would be far beyond what a single researcher or a traditional research group could carry out.

  5. High Energy Density Physics:. the Laser Field of Tomorrow

    NASA Astrophysics Data System (ADS)

    Freeman, Richard R.

    2013-03-01

    Ever since its invention, the laser has become an increasingly important tool for physics research. Indeed, the laser has made it possible to not only study many extant physical phenomena, but also to actually produce matter in conditions that don't exist in nature, or more precisely, don't exist on the earth. In this lecture, I discuss how the development of lasers that produce ultra-short (˜fsec) and ultra-intense (≥1020 W/cm2) laser pulses actually produce plasmas that are at a density and temperature that exist only in stars. In doing so I discuss some of the basics of these extreme pulses interacting with electrons, yielding surprisingly intriguing physical phenomena. Finally, I argue that this field is an essential element in any comprehensive physical research endeavor, explicitly citing its fundamental relationship with the development of clean, unlimited fusion energy power.

  6. Intermolecular electrostatic energies using density fitting

    PubMed Central

    Cisneros, G. Andrés; Piquemal, Jean-Philip; Darden, Thomas A.

    2009-01-01

    A method is presented to calculate the electron-electron and nuclear-electron intermolecular Coulomb interaction energy between two molecules by separately fitting the unperturbed molecular electron density of each monomer. This method is based on the variational Coulomb fitting method which relies on the expansion of the ab initio molecular electron density in site-centered auxiliary basis sets. By expanding the electron density of each monomer in this way the integral expressions for the intermolecular electrostatic calculations are simplified, lowering the operation count as well as the memory usage. Furthermore, this method allows the calculation of intermolecular Coulomb interactions with any level of theory from which a one-electron density matrix can be obtained. Our implementation is initially tested by calculating molecular properties with the density fitting method using three different auxiliary basis sets and comparing them to results obtained from ab initio calculations. These properties include dipoles for a series of molecules, as well as the molecular electrostatic potential and electric field for water. Subsequently, the intermolecular electrostatic energy is tested by calculating ten stationary points on the water dimer potential-energy surface. Results are presented for electron densities obtained at four different levels of theory using two different basis sets, fitted with three auxiliary basis sets. Additionally, a one-dimensional electrostatic energy surface scan is performed for four different systems (H2O dimer, Mg2+–H2O, Cu+–H2O, and n-methyl-formamide dimer). Our results show a very good agreement with ab initio calculations for all properties as well as interaction energies. PMID:16095348

  7. Strongly Interacting Matter at High Energy Density

    SciTech Connect

    McLerran,L.

    2008-09-07

    This lecture concerns the properties of strongly interacting matter (which is described by Quantum Chromodynamics) at very high energy density. I review the properties of matter at high temperature, discussing the deconfinement phase transition. At high baryon density and low temperature, large N{sub c} arguments are developed which suggest that high baryonic density matter is a third form of matter, Quarkyonic Matter, that is distinct from confined hadronic matter and deconfined matter. I finally discuss the Color Glass Condensate which controls the high energy limit of QCD, and forms the low x part of a hadron wavefunction. The Glasma is introduced as matter formed by the Color Glass Condensate which eventually thermalizes into a Quark Gluon Plasma.

  8. High-energy-density composite flywheel

    NASA Astrophysics Data System (ADS)

    Satchwell, D. L.; Towgood, D. A.

    1980-02-01

    A flywheel was designed and fabricated to demonstrate a high energy density of 80 w-h/kg in the rotor. The rotor design consists of a multiring, subcircular rim made of S-glass/epoxy composite and Kevlar/epoxy composite materials and mounted on a spoked hub made of graphite/epoxy composite materials.

  9. On the energy density of helical proteins.

    PubMed

    Barros, Manuel; Ferrández, Angel

    2014-12-01

    We solve the problem of determining the energy actions whose moduli space of extremals contains the class of Lancret helices with a prescribed slope. We first see that the energy density should be linear both in the total bending and in the total twisting, such that the ratio between the weights of them is the prescribed slope. This will give an affirmative answer to the conjecture stated in Barros and Ferrández (J Math Phys 50:103529, 2009). Then, we normalize to get the best choice for the helical energy. It allows us to show that the energy, for instance of a protein chain, does not depend on the slope and is invariant under homotopic changes of the cross section which determines the cylinder where the helix is lying. In particular, the energy of a helix is not arbitrary, but it is given as natural multiples of some basic quantity of energy. PMID:24390481

  10. Kinetic energy density dependent approximations to the exchange energy

    NASA Astrophysics Data System (ADS)

    Ernzerhof, Matthias; Scuseria, Gustavo E.

    1999-07-01

    Two nonempirical kinetic energy density dependent approximations are introduced. First, the local τ approximation (LTA) is proposed in which the exchange energy Ex depends only on a kinetic energy density τ. This LTA scheme appears to be complementary to the local spin density (LSD) approximation in the sense that its exchange contribution to the atomization energy ΔEx=Exatoms-Exmolecule is fairly accurate for systems where LSD fails. On the other hand, in cases where LSD works well LTA results for ΔEx are worse. Secondly, the τPBE approximation to Ex is developed which combines some of the advantages of LTA and of the Perdew-Burke-Ernzerhof (PBE) exchange functional. Like the PBE exchange functional, τPBE is free of empirical parameters. Furthermore, it yields improved atomization energies compared to the PBE approximation.

  11. Nonlocal kinetic-energy-density functionals

    SciTech Connect

    Garcia-Gonzalez, P.; Alvarellos, J.E.; Chacon, E. |

    1996-04-01

    In this paper we present nonlocal kinetic-energy functionals {ital T}[{ital n}] within the average density approximation (ADA) framework, which do not require any extra input when applied to any electron system and recover the exact kinetic energy and the linear response function of a homogeneous system. In contrast with previous ADA functionals, these present good behavior of the long-range tail of the exact weight function. The averaging procedure for the kinetic functional (averaging the Fermi momentum of the electron gas, instead of averaging the electron density) leads to a functional without numerical difficulties in the calculation of extended systems, and it gives excellent results when applied to atoms and jellium surfaces. {copyright} {ital 1996 The American Physical Society.}

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

    SciTech Connect

    2010-04-01

    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.

  13. Laser Experiments for High Energy Density Science

    SciTech Connect

    Kumar, G. Ravindra

    2010-11-23

    High energy density science probes some of the most basic scientific questions that cut across traditional disciplines. The advent of table top, terawatt, femtosecond lasers promises to revolutionize this area by the use of precise experimental techniques on the one hand and testing of models and computer simulations on the other. In this paper, we present some of our results on hot electron generation, giant magnetic fields and ultrafast plasma dynamics using such experiments and theoretical modeling.

  14. Alternative Approaches to High Energy Density Fusion

    NASA Astrophysics Data System (ADS)

    Hammer, J.

    2016-03-01

    This paper explores selected approaches to High Energy Density (HED) fusion, beginning with discussion of ignition requirements at the National Ignition Facility (NIF). The needed improvements to achieve ignition are closely tied to the ability to concentrate energy in the implosion, manifested in the stagnation pressure, Pstag . The energy that must be assembled in the imploded state to ignite varies roughly as Pstag -2, so among other requirements, there is a premium on reaching higher Pstag to achieve ignition with the available laser energy. The U.S. inertial confinement fusion program (ICF) is pursuing higher Pstag on NIF through improvements to capsule stability and symmetry. One can argue that recent experiments place an approximate upper bound on the ultimate ignition energy requirement. Scaling the implosions consistently in spatial, temporal and energy scales shows that implosions of the demonstrated quality ignite robustly at 9-15 times the current energy of NIF. While lasers are unlikely to reach that bounding energy, it appears that pulsed-power sources could plausibly do so, giving a range of paths forward for ICF depending on success in improving energy concentration. In this paper, I show the scaling arguments then discuss topics from my own involvement in HED fusion. The recent Viewfactor experiments at NIF have shed light on both the observed capsule drive deficit and errors in the detailed modelling of hohlraums. The latter could be important factors in the inability to achieve the needed symmetry and energy concentration. The paper then recounts earlier work in Fast Ignition and the uses of pulsed- power for HED and fusion applications. It concludes with a description of a method for improving pulsed-power driven hohlraums that could potentially provide a factor of 10 in energy at NIF-like drive conditions and reach the energy bound for indirect drive ICF.

  15. Actual and prescribed energy and protein intakes for very low birth weight infants: An observational study

    NASA Astrophysics Data System (ADS)

    Allevato, Anthony J.

    Objectives: To determine (1) whether prescribed and delivered energy and protein intakes during the first two weeks of life met Ziegler's estimated requirements for Very Low Birth Weight (VLBW) infants, (2) if actual energy during the first week of life correlated with time to regain birth weight and reach full enteral nutrition (EN) defined as 100 kcal/kg/day, (3) if growth velocity from time to reach full EN to 36 weeks' postmenstrual age (PMA) met Ziegler's estimated fetal growth velocity (16 g/kg/day), and (4) growth outcomes at 36 weeks' PMA. Study design: Observational study of feeding, early nutrition and early growth of 40 VLBW infants <30 weeks GA at birth in three newborn intensive care units NICUs. Results: During the first week of life, the percentages of prescribed and delivered energy (69% [65 kcal/kg/day]) and protein (89% [3.1 g/kg/day]) were significantly less than theoretical estimated requirements. Delivered intakes were 15% less than prescribed because of numerous interruptions in delivery and medical complications. During the second week, the delivered intakes of energy (90% [86 kcal/kg/day]) and protein (102% [3.5 g/kg/day]) improved although the differences between prescribed and delivered were consistently 15%. Energy but not protein intake during the first week was significantly related to time to reach full EN. Neither energy nor protein intake significantly correlated with days to return to birth weight. The average growth velocity from the age that full EN was attained to 36 weeks' PMA (15 g/kg/day) was significantly less than the theoretical estimated fetal growth velocity (16 g/kg/day) (p<0.03). A difference of 1 g/kg/day represents a total deficit of 42 - 54 grams over the course of a month. At 36 weeks' PMA, 53% of the VLBW infants had extrauterine growth restriction, or EUGR (<10th percentile) on the Fenton growth grid and 34% had EUGR on the Lubchenco growth grid. Conclusions: The delivered nutrient intakes were consistently less

  16. Discussion of the reliability of electron densities and energies interpreted from data and limits on the proton energy and density

    NASA Technical Reports Server (NTRS)

    Beard, D. B.

    1972-01-01

    Analysis of radio observations of Jupiter were changed to take into account the antenna resolution. A dipole magnetic field with a surface equatorial value of 7 gauss is assumed. The electron temperature is found to increase for r 2.5 Jupiter radii with decreasing r as 1/r cubed, reaching a peak of about 100 MeV at r = 2.5 Jupiter radii. For r 2.5 Jupiter radii, the electron temperature goes as r to the 6th power because of energy lost to radiation. The consequences of making an upper estimate on the proton flux by assuming the magnetic field is loaded with all the energetic protons it can hold are described. The upper limits of proton energy, density, flux, and energy flux are calculated for 1, 2, 2.5, 3, and 6 Jupiter radii. The proton energy and velocity estimates are considered to be fairly reliable; the upper limit to the number density is probably much higher than actuality.

  17. Actual Evapotranspiration using a two source energy balance model and gridded reference ET0

    NASA Astrophysics Data System (ADS)

    Geli, H. M.; Neale, C. M.; Verdin, J. P.; Senay, G. B.; Hobbins, M.

    2013-12-01

    In an ongoing effort to provide estimates of actual evapotranspiration (ETa) at different spatial scales from local to regional this study investigate the use of a newly under development gridded reference ET0 product. This study is conducted within the context of a USGS project aimed to provide a standardized framework for the remote sensing of ETa that can be followed in the implementation of the WaterSMART program. Most thermal remote sensing based models provide instantaneous estimates of latent heat flux which then can be extrapolated to daily ETa. In many cases extrapolation is achieved using the ETref method. At field scales reference ET0, daily and instantaneous values, are obtained from point-based/local scale measurements. When considering regional scale this local scale estimates of ET0 might not be appropriate to account for the corresponding spatial variability. This analysis provides a comparison of ETa estimates based on a two source energy balance approach using point-based and gridded reference ET0 data. The two source energy balance SEBS (Norman et al. 1995) is used to calculate surface energy fluxes and ETa. Data from Palo Verdi Irrigation District (PVID), CA is used during the analysis. The area which extends over 500 km2 covered mostly with alfalfa, cotton and vegetable crops. Ground-based hydrometeorological data including reference ET0 are provided from a nearby weather stations. CONUS wide gridded reference ET0 which being developed by NOAA using NLDAS-phase 2 weather forcing are used. Both estimates of ETa_point and ETa_NLDAS based on ground and gridded ET0 data, respectively, are compared to ground-based measurement. Preliminary results of the comparison will be presented to highlight on the potential use of such gridded ET0 data in the use of remote sensing of ETa at regional scales application. References Norman, J. M., W. P. Kustas, & K. S. Humes, 1995: A two-source approach for estimating soil and vegetation energy fluxes in

  18. Inductor Geometry With Improved Energy Density

    SciTech Connect

    Cui, H; Ngo, KDT; Moss, J; Lim, MHF; Rey, E

    2014-10-01

    The "constant-flux" concept is leveraged to achieve high magnetic-energy density, leading to inductor geometries with height significantly lower than that of conventional products. Techniques to shape the core and to distribute the winding turns to shape a desirable field profile are described for the two basic classes of magnetic geometries: those with the winding enclosed by the core and those with the core enclosed by the winding. A relatively constant flux distribution is advantageous not only from the density standpoint, but also from the thermal standpoint via the reduction of hot spots, and from the reliability standpoint via the suppression of flux crowding. In this journal paper on a constant-flux inductor (CFI) with enclosed winding, the foci are operating principle, dc analysis, and basic design procedure. Prototype cores and windings were routed from powder-iron disks and copper sheets, respectively. The design of CFI was validated by the assembled inductor prototype.

  19. High energy density capacitor testing for the AFWL SHIVA

    SciTech Connect

    Smith, D.L.; Reinovsky, R.E.

    1981-01-01

    The SHIVA II Prime upgrade consists of replacing the existing 3.3 kJ, 1.85 ..mu..F capacitors with plug-in higher energy density capacitors. Based on capacitor development work by manufacturers it appears that a nominal 6 ..mu..F, 60 kV capacitor in an 11'' x 14'' can is near the limits of current technology. Using the 6 ..mu..F, 10.8 kJ capacitor results in a factor of 3 increase in stored energy at no increase in operational voltage. The equivalent system capacitance will then be 864 ..mu..F at 120 kV (+-60 kV) or 6.22 MJ. The best testing technique is one which duplicates, as nearly as reasonable, the actual parameters the capacitors would see in the full-scale system. Lifetime testing and analysis of small samples of high energy density (HED) discharge capacitors at the AFWL were conducted to find a component suitable for upgrading the SHIVA capacitor bank to a 6 MJ facility. Evaluation was performed with discharge conditions of approximately 250 kA per capacitor at 60 to 70% reversal and < 2 ..mu..s quarter period. Dielectric systems including Kraft paper with caster oil impregnant and Kraft paper, polypropylene with DiOctyl Phthalate (DOP) impregnant were tested.

  20. Density of States for Warped Energy Bands

    PubMed Central

    Mecholsky, Nicholas A.; Resca, Lorenzo; Pegg, Ian L.; Fornari, Marco

    2016-01-01

    Warping of energy bands can affect the density of states (DOS) in ways that can be large or subtle. Despite their potential for significant practical impacts on materials properties, these effects have not been rigorously demonstrated previously. Here we rectify this using an angular effective mass formalism that we have developed. To clarify the often confusing terminology in this field, “band warping” is precisely defined as pertaining to any multivariate energy function E(k) that does not admit a second-order differential at an isolated critical point in k-space, which we clearly distinguish from band non-parabolicity. We further describe band “corrugation” as a qualitative form of band warping that increasingly deviates from being twice differentiable at an isolated critical point. These features affect the density-of-states and other parameters ascribed to band warping in various ways. We demonstrate these effects, providing explicit calculations of DOS and their effective masses for warped energy dispersions originally derived by Kittel and others. Other physical and mathematical examples are provided to demonstrate fundamental distinctions that must be drawn between DOS contributions that originate from band warping and contributions that derive from band non-parabolicity. For some non-degenerate bands in thermoelectric materials, this may have profound consequences of practical interest. PMID:26905029

  1. Density of States for Warped Energy Bands

    NASA Astrophysics Data System (ADS)

    Mecholsky, Nicholas A.; Resca, Lorenzo; Pegg, Ian L.; Fornari, Marco

    2016-02-01

    Warping of energy bands can affect the density of states (DOS) in ways that can be large or subtle. Despite their potential for significant practical impacts on materials properties, these effects have not been rigorously demonstrated previously. Here we rectify this using an angular effective mass formalism that we have developed. To clarify the often confusing terminology in this field, “band warping” is precisely defined as pertaining to any multivariate energy function E(k) that does not admit a second-order differential at an isolated critical point in k-space, which we clearly distinguish from band non-parabolicity. We further describe band “corrugation” as a qualitative form of band warping that increasingly deviates from being twice differentiable at an isolated critical point. These features affect the density-of-states and other parameters ascribed to band warping in various ways. We demonstrate these effects, providing explicit calculations of DOS and their effective masses for warped energy dispersions originally derived by Kittel and others. Other physical and mathematical examples are provided to demonstrate fundamental distinctions that must be drawn between DOS contributions that originate from band warping and contributions that derive from band non-parabolicity. For some non-degenerate bands in thermoelectric materials, this may have profound consequences of practical interest.

  2. Surprises in High Energy Density Physics

    NASA Astrophysics Data System (ADS)

    Rose, S. J.

    2010-01-01

    Edward Teller's work on what is now called High Energy Density Physics (HEDP) is not so well known as some of his work in other areas of physics. Yet he made substantial contributions since the 1940s and the models that he developed and the problems that he worked on are still relevant today. In this talk we shall look at two major areas in HEDP with the first treated more historically and the second more with a view to recent work that the author and others have undertaken which perhaps indicates future directions.

  3. High energy density redox flow device

    DOEpatents

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

    2014-05-13

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

  4. Research on high energy density capacitor materials

    NASA Technical Reports Server (NTRS)

    Somoano, Robert

    1988-01-01

    The Pulsed Plasma thruster is the simplest of all electric propulsion devices. It is a pulsed device which stores energy in capacitors for each pulse. The lifetimes and energy densities of these capacitors are critical parameters to the continued use of these thrusters. This report presents the result of a research effort conducted by JPL into the materials used in capacitors and the modes of failure. The dominant failure mechanism was determined to be material breakdown precipitated by heat build-up within the capacitors. The presence of unwanted gas was identified as the source of the heat. An aging phenomena was discovered in polycarbonate based capacitors. CO build-up was noted to increase with the number of times the capacitor had been discharged. Improved quality control was cited as being essential for the improvement of capacitor lifetimes.

  5. Diffuse Waves and Energy Densities Near Boundaries

    NASA Astrophysics Data System (ADS)

    Sanchez-Sesma, F. J.; Rodriguez-Castellanos, A.; Campillo, M.; Perton, M.; Luzon, F.; Perez-Ruiz, J. A.

    2007-12-01

    Green function can be retrieved from averaging cross correlations of motions within a diffuse field. In fact, it has been shown that for an elastic inhomogeneous, anisotropic medium under equipartitioned, isotropic illumination, the average cross correlations are proportional to the imaginary part of Green function. For instance coda waves are due to multiple scattering and their intensities follow diffusive regimes. Coda waves and the noise sample the medium and effectively carry information along their paths. In this work we explore the consequences of assuming both source and receiver at the same point. From the observable side, the autocorrelation is proportional to the energy density at a given point. On the other hand, the imaginary part of the Green function at the source itself is finite because the singularity of Green function is restricted to the real part. The energy density at a point is proportional with the trace of the imaginary part of Green function tensor at the source itself. The Green function availability may allow establishing the theoretical energy density of a seismic diffuse field generated by a background equipartitioned excitation. We study an elastic layer with free surface and overlaying a half space and compute the imaginary part of the Green function for various depths. We show that the resulting spectrum is indeed closely related to the layer dynamic response and the corresponding resonant frequencies are revealed. One implication of present findings lies in the fact that spatial variations may be useful in detecting the presence of a target by its signature in the distribution of diffuse energy. These results may be useful in assessing the seismic response of a given site if strong ground motions are scarce. It suffices having a reasonable illumination from micro earthquakes and noise. We consider that the imaginary part of Green function at the source is a spectral signature of the site. The relative importance of the peaks of

  6. High energy density aluminum-oxygen cell

    NASA Technical Reports Server (NTRS)

    Rudd, E. J.; Gibbons, D. W.

    1993-01-01

    An alternative to a secondary battery as the power source for vehicle propulsion is a fuel cell. An example of this is the metal-air fuel cell using metals such as aluminum, zinc, or iron. Aluminum is a particularly attractive candidate, having high energy and power densities, being environmentally acceptable, and having a large, established industrial base for production and distribution. An aluminum-oxygen system is currently under development for a UUV test vehicle, and recent work has focussed upon low corrosion aluminum alloys and an electrolyte management system for processing the by-products of the energy-producing reactions. This paper summarizes the progress made in both areas. Anode materials capable of providing high utilization factors over current densities ranging from S to 150 mA/sq cm have been identified. These materials are essential to realizing an acceptable mission life for the UUV. With respect to the electrolyte management system, a filter/precipitator unit has been successfully operated for over 250 hours in a large scale, half-cell system.

  7. High energy density aluminum-oxygen cell

    NASA Astrophysics Data System (ADS)

    Rudd, E. J.; Gibbons, D. W.

    1993-11-01

    An alternative to a secondary battery as the power source for vehicle propulsion is a fuel cell. An example of this is the metal-air fuel cell using metals such as aluminum, zinc, or iron. Aluminum is a particularly attractive candidate, having high energy and power densities, being environmentally acceptable, and having a large, established industrial base for production and distribution. An aluminum-oxygen system is currently under development for a UUV test vehicle, and recent work has focussed upon low corrosion aluminum alloys and an electrolyte management system for processing the by-products of the energy-producing reactions. This paper summarizes the progress made in both areas. Anode materials capable of providing high utilization factors over current densities ranging from S to 150 mA/sq cm have been identified. These materials are essential to realizing an acceptable mission life for the UUV. With respect to the electrolyte management system, a filter/precipitator unit has been successfully operated for over 250 hours in a large scale, half-cell system.

  8. High Energy Density aluminum/oxygen cell

    NASA Astrophysics Data System (ADS)

    Rudd, E. J.; Gibbons, D. W.

    An alternative to a secondary battery as the power source for vehicle propulsion is a fuel cell, an example of which is the metal/air cell using metals such as aluminum, zinc, or iron. Aluminum is a particularly attractive candidate, with high energy and power densities, environmentally acceptable and having a large, established industrial base for production and distribution. An aluminum/oxygen system is currently under development for a prototype unmanned, undersea vehicle (UUV) for the US navy and recent work has focussed upon low corrosion aluminum alloys, and an electrolyte management system for processing the by-products of the energy-producing reactions. This paper summarizes the progress made in both areas. Anode materials capable of providing high utilization factors over current densities ranging from 5 to 150 mA/cm 2 have been identified, such materials being essential to realize mission life for the UUV. With respect to the electrolyte management system, a filter/precipitator unit has been successfully operated for over 250 h in a large scale, half-cell system.

  9. Actual evapotranspiration modeling using the operational Simplified Surface Energy Balance (SSEBop) approach

    USGS Publications Warehouse

    Savoca, Mark E.; Senay, Gabriel B.; Maupin, Molly A.; Kenny, Joan F.; Perry, Charles A.

    2013-01-01

    Remote-sensing technology and surface-energy-balance methods can provide accurate and repeatable estimates of actual evapotranspiration (ETa) when used in combination with local weather datasets over irrigated lands. Estimates of ETa may be used to provide a consistent, accurate, and efficient approach for estimating regional water withdrawals for irrigation and associated consumptive use (CU), especially in arid cropland areas that require supplemental water due to insufficient natural supplies from rainfall, soil moisture, or groundwater. ETa in these areas is considered equivalent to CU, and represents the part of applied irrigation water that is evaporated and/or transpired, and is not available for immediate reuse. A recent U.S. Geological Survey study demonstrated the application of the remote-sensing-based Simplified Surface Energy Balance (SSEB) model to estimate 10-year average ETa at 1-kilometer resolution on national and regional scales, and compared those ETa values to the U.S. Geological Survey’s National Water-Use Information Program’s 1995 county estimates of CU. The operational version of the operational SSEB (SSEBop) method is now used to construct monthly, county-level ETa maps of the conterminous United States for the years 2000, 2005, and 2010. The performance of the SSEBop was evaluated using eddy covariance flux tower datasets compiled from 2005 datasets, and the results showed a strong linear relationship in different land cover types across diverse ecosystems in the conterminous United States (correlation coefficient [r] ranging from 0.75 to 0.95). For example, r for woody savannas (0.75), grassland (0.75), forest (0.82), cropland (0.84), shrub land (0.89), and urban (0.95). A comparison of the remote-sensing SSEBop method for estimating ETa and the Hamon temperature method for estimating potential ET (ETp) also was conducted, using regressions of all available county averages of ETa for 2005 and 2010, and yielded correlations of r = 0

  10. High Energy Density Matter for Rocket Propulsion

    NASA Technical Reports Server (NTRS)

    Carrick, Patrick G.

    1996-01-01

    The objective of the High Energy Density Matter (HEDM) program is to identify, develop, and exploit high energy atomic and molecular systems as energetic sources for rocket propulsion applications. It is a high risk, high payoff program that incorporates both basic and applied research, experimental and theoretical efforts, and science and engineering efforts. The HEDM program is co-sponsored by the Air Force Office of Scientific Research (AFOSR) and the Phillips Laboratory (PURKS). It includes both in-house and contracted University/Industry efforts. Technology developed by the HEDM program offers the opportunity for significant breakthroughs in propulsion system capabilities over the current state-of-the-art. One area of great interest is the use of cryogenic solids to increase the density of the propellant and to act as a stable matrix for storage of energetic materials. No cryogenic solid propellant has ever been used in a rocket, and there remain engineering challenges to such a propellant. However, these solids would enable a wide class of highly energetic materials by providing an environment that is at very low temperatures and is a physical barrier to recombination or energy loss reactions. Previous to our experiments only hydrogen atoms had been isolated in solid hydrogen. To date we have succeeded in trapping B, Al, Li, N, and Mg atoms in solid H2. Small molecules, such as B2 and LiB, are also of interest. Current efforts involve the search for new energetic small molecules, increasing free radical concentrations up to 5 mole percent, and scale-up for propulsion testing.

  11. Perspectives on High-Energy-Density Physics

    NASA Astrophysics Data System (ADS)

    Drake, R. Paul

    2008-11-01

    Much of 21st century plasma physics will involve work to produce, understand, control, and exploit very non-traditional plasmas. High-energy density (HED) plasmas are often examples, variously involving strong Coulomb interactions and few particles per Debeye sphere, dominant radiation effects, strongly relativistic effects, or strongly quantum-mechanical behavior. Indeed, these and other modern plasma systems often fall outside the early standard theoretical definitions of ``plasma''. This presentation will focus on two types of HED plasmas that exhibit non-traditional behavior. Our first example will be the plasmas produced by extremely strong shock waves. Shock waves are present across the entire realm of plasma densities, often in space or astrophysical contexts. HED shock waves (at pressures > 1 Mbar) enable studies in many areas, from equations of state to hydrodynamics to radiation hydrodynamics. We will specifically consider strongly radiative shocks, in which the radiative energy fluxes are comparable to the mechanical energy fluxes that drive the shocks. Modern HED facilities can produce such shocks, which are also present in dense, energetic, astrophysical systems such as supernovae. These shocks are also excellent targets for advanced simulations due to their range of spatial scales and complex radiation transport. Our second example will be relativistic plasmas. In general, these vary from plasmas containing relativistic particle beams, produced for some decades in the laboratory, to the relativistic thermal plasmas present for example in pulsar winds. Laboratory HED relativistic plasmas to date have been those produced by laser beams of irradiance ˜ 10^18 to 10^22 W/cm^2 or by accelerator-produced HED electron beams. These have applications ranging from generation of intense x-rays to production of proton beams for radiation therapy to acceleration of electrons. Here we will focus on electron acceleration, a spectacular recent success and a rare

  12. Energy density of bloaters in the upper Great Lakes

    USGS Publications Warehouse

    Pothoven, Steven A.; Bunnell, David B.; Madenjian, Charles P.; Gorman, Owen T.; Roseman, Edward F.

    2012-01-01

    We evaluated the energy density of bloaters Coregonus hoyi as a function of fish size across Lakes Michigan, Huron, and Superior in 2008–2009 and assessed how differences in energy density are related to factors such as biomass density of bloaters and availability of prey. Additional objectives were to compare energy density between sexes and to compare energy densities of bloaters in Lake Michigan between two time periods (1998–2001 and 2008–2009). For the cross-lake comparisons in 2008, energy density increased with fish total length (TL) only in Lake Michigan. Mean energy density adjusted for fish size was 8% higher in bloaters from Lake Superior than in bloaters from Lake Huron. Relative to fish in these two lakes, small (175 mm TL) bloaters had higher energy density. In 2009, energy density increased with bloater size, and mean energy density adjusted for fish size was about 9% higher in Lake Michigan than in Lake Huron (Lake Superior was not sampled during 2009). Energy density of bloaters in Lake Huron was generally the lowest among lakes, reflecting the relatively low densities of opossum shrimp Mysis diluviana and the relatively high biomass of bloaters reported for that lake. Other factors, such as energy content of prey, growing season, or ontogenetic differences in energy use strategies, may also influence cross-lake variation in energy density. Mean energy density adjusted for length was 7% higher for female bloaters than for male bloaters in Lakes Michigan and Huron. In Lake Superior, energy density did not differ between males and females. Finally, energy density of bloaters in Lake Michigan was similar between the periods 2008–2009 and 1998–2001, possibly due to a low population abundance of bloaters, which could offset food availability changes linked to the loss of prey such as the amphipods Diporeia spp.

  13. SURFACE SYMMETRY ENERGY OF NUCLEAR ENERGY DENSITY FUNCTIONALS

    SciTech Connect

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

    2010-12-20

    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.

  14. Simulation of High Energy Density Laboratory Plasmas

    NASA Astrophysics Data System (ADS)

    Guzik, Joyce

    2004-05-01

    High Energy Density plasmas are found in astrophysical environments, have been generated in past underground nuclear tests, and can be created in the laboratory by, e.g. laser or pulsed power experiments. These experiments can be used to validate simulation capabilities that are being developed to advance our understanding of plasma physics, and to develop predictive capabilities for HED plasma applications such as fusion energy. In this talk we will briefly introduce the subject of simulating HED plasmas using radiation hydrodynamics codes. We will give examples of simple test problems, showing how a problem is approached, including geometry specifications, simplifying assumptions, zoning, initial and boundary conditions, basic data on opacities and EOS, and illustrate sensitivities of results to variations. We will also show highlights of work at Los Alamos to validate codes, provide basic data, and develop applications, for example: 1) studying phenomena such as Rayleigh-Taylor and Richtmeyer-Meshkov instabilities, ablation, and supersonic jets at the Omega laser in Rochester and the Sandia Z Machine; 2) quantum molecular dynamics simulations which have recently led to a semi-classical, particle-particle particle-mesh code that allows ultra-fast simulations involving tens of thousands of particles to calculate properties of hot dense plasmas; 3) efforts to experimentally demonstrate the physics basis for magnetized target fusion (MTF), a potentially low cost path to fusion, intermediate in plasma regime between magnetic and inertial fusion energy.

  15. Energy density fluctuations in early universe

    SciTech Connect

    Guardo, G. L.; Ruggieri, M.; Greco, V.

    2014-05-09

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

  16. Perspectives on high-energy-density physicsa)

    NASA Astrophysics Data System (ADS)

    Drake, R. P.

    2009-05-01

    Much of 21st century plasma physics will involve work to produce, understand, control, and exploit very nontraditional plasmas. High-energy-density (HED) plasmas are often examples, variously involving strong Coulomb interactions and ≪1 particles per Debye sphere, dominant radiation effects, and strongly relativistic or strongly quantum-mechanical behavior. Indeed, these and other modern plasma systems often fall outside the early standard theoretical definitions of "plasma." Here the specific ways in which HED plasmas differ from traditional plasmas are discussed. This is first done by comparison of important physical quantities across the parameter regime accessible by existing or contemplated experimental facilities. A specific discussion of some illustrative cases follows, including strongly radiative shocks and the production of relativistic, quasimonoenergetic beams of accelerated electrons.

  17. Surface energies of semiconductors by the energy density method

    NASA Astrophysics Data System (ADS)

    Yu, Min; Martin, Richard M.

    2008-03-01

    Energy Density formalism within the first-principles pseudopotential density functional theory has been proposed by Chetty and Martin^1 in 1990s. Although the energy density function is non-unique, nevertheless integrals over surface regions provide unique results for surface energies, and calculations have been carried out by several groups^2,3 to study the polar surfaces and interfaces of solid state systems such as GaAs (111) and (111) polar surfaces. In our work, we apply this method to wurtzite CdSe to determine the energy of of various polar surfaces such as (0001),(0001), and non-polar surfaces such as (1010),(1120), from which we can estimate the equilibrium crystal shape for large nanoclusters. 1. N. Chetty and Richard M. Martin, Phys. Rev. B 45, 6074 (1992). 2. K. Rapcewicz, B. Chen, B. Yakobson, and J. Bernholc, Phys. Rev. B 57, 7281 (1998). 3. N. Moll, A. Kley, E. Pehlke, and M. Scheffler, Phys. Rev. B 54, 8844 (1996).

  18. The economics of obesity: dietary energy density and energy cost.

    PubMed

    Drewnowski, Adam; Darmon, Nicole

    2005-07-01

    Highest rates of obesity and diabetes in the United States are found among the lower-income groups. The observed links between obesity and socioeconomic position may be related to dietary energy density and energy cost. Refined grains, added sugars, and added fats are among the lowest-cost sources of dietary energy. They are inexpensive, good tasting, and convenient. In contrast, the more nutrient-dense lean meats, fish, fresh vegetables, and fruit generally cost more. An inverse relationship between energy density of foods (kilojoules per gram) and their energy cost (dollars per megajoule) means that the more energy-dense diets are associated with lower daily food consumption costs and may be an effective way to save money. However, economic decisions affecting food choice may have physiologic consequences. Laboratory studies suggest that energy-dense foods and energy-dense diets have a lower satiating power and may result in passive overeating and therefore weight gain. Epidemiologic analyses suggest that the low-cost energy-dense diets also tend to be nutrient poor. If the rise in obesity rates is related to the growing price disparity between healthy and unhealthy foods, then the current strategies for obesity prevention may need to be revised. Encouraging low-income families to consume healthier but more costly foods to prevent future disease can be construed as an elitist approach to public health. Limiting access to inexpensive foods through taxes on frowned upon fats and sweets is a regressive measure. The broader problem may lie with growing disparities in incomes and wealth, declining value of the minimum wage, food imports, tariffs, and trade. Evidence is emerging that obesity in America is a largely economic issue. PMID:16002835

  19. Effect of the Vacuum Energy Density on Graviton Propagation

    NASA Astrophysics Data System (ADS)

    Modanese, Giovanni; Fontana, Giorgio

    2004-02-01

    It has been known for some time that the value Λ of the vacuum energy density affects the propagation equation for gravitons - the analogue of photons for the gravitational field. (For historical reasons, Λ is also called ``cosmological constant''.) More precisely, if Λ is not zero, then a mass term appears in the propagation equation, such that m2=-Λ. As a consequence, the polarization states of gravitons also change, because a massless particle has only two polarization states while a massive particle has more. This effect of the Λ-term has been confirmed by recent calculations in a curved background, which is actually the only proper setting, since solutions of the classical Einstein equations in the presence of a Λ-term represent a space with constant curvature. A real value for the mass (when Λ<0) will show up as a slight exponential damping in the gravitational potential, which is however strongly constrained by astronomical data. The consequences of an imaginary mass (for Λ>0) are still unclear; on general grounds, one can expect the onset of instabilities in this case. This is also confirmed by numerical simulations of quantum gravity which became recently available. These properties gain a special interest in consideration of the following. (1) The most recent cosmological data indicate that Λ is positive and of the order of 0.1 J/m3. Is this value compatible with a stable propagation of gravitons? (2) The answer to the previous question lies perhaps in the scale dependence of the effective value of Λ. It could then happen that Λ is actually negative at the small distance/large energy scale at which the quantum behavior of gravitational fields and waves becomes relevant. Applications for an advanced propulsion scheme is that local contributions to the vacuum energy density (remarkably in superconductors in certain states, and in very strong static electromagnetic fields) can change locally the sign of Λ, and so affect locally the propagation

  20. The Nuclear Energy Density Functional Formalism

    NASA Astrophysics Data System (ADS)

    Duguet, T.

    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 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 mathematically meaningful fashion even if E[g',g] does not derive from a genuine Hamilton operator. In particular, the restoration of symmetries can be entirely formulated without making 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 physical standpoint. The price at which the latter can be enforced as well in the future is eventually alluded to.

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

    SciTech Connect

    Liu Min; Wang Ning; Li Zhuxia; Zhang Fengshou

    2010-12-15

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

  2. Building a Universal Nuclear Energy Density Functional

    SciTech Connect

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

    2012-12-30

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

  3. Superintense ion beam with high energy density

    NASA Astrophysics Data System (ADS)

    Dudnikov, Vadim; Dudnikova, Galina

    2008-04-01

    The energy density of ion beam accumulated in a storage ring can be increased dramatically with using of space charge compensation as was demonstrated in experiments [1]. The intensity of said superintense beam can be far greater than a space charge limit without space charge compensation. The model of secondary plasma build up with secondary ion-electron emission as a source of delayed electrons has been presented and discussed. This model can be used for explanation of bunched beam instability with electron surviving after gap, for prediction of e-cloud generation in coasting and long bunches beam, and can be important for pressure rise in worm and cold sections of storage rings. A fast desorption by ion of physically adsorbed molecules can explain a ``first pulse Instability''. Application of this model for e-p instability selfstabilization and superintense circulating beam accumulation is considered. Importance of secondary plasma for high perveance ion beam stabilization in ion implantation will be considered. Preliminary results of simulation of electron and ion accumulation will be presented. [1]. Belchenko et al., Xth International Particle Accelerator Conference, Protvino, 1977, Vol. 2, p. 287.

  4. Estimating the actual ET from a pecan farm using the OPEC energy-balance and Penman- Monteith methods

    NASA Astrophysics Data System (ADS)

    Debele, B.; Bawazir, S. A.

    2006-12-01

    Accurate estimation of ET from field crops/orchards is the basis for better irrigation water management. In areas like Mesilla Valley, NM, where water is scarce, it is even more important to precisely determine the crop ET. An OPEC energy balance system was run for 117 days (June 22 October 14, 2001) in a matured pecan farm at Mesilla Valley, NM. The actual evapotranspiration (ET) from pecan orchards was determined from the surface energy balance as a residual, having measured the net radiation, soil heat flux, and sensible heat components using the OPEC method. Since pecans are large trees, we have also examined the effect of including thermal energies stored in the air (Ga) and plant canopy (Gc), on top of the commonly used thermal energy stored in the soil (Gs), on surface energy balance, and hence ET. The results indicate that incorporating thermal energies stored in the air and canopy has a significant effect on total energy storage for shorter temporal resolutions, such as 30-minutes and an hour. Conversely, for longer temporal resolutions (e.g., diurnal and monthly averages), the effect of including thermal energies stored in the air and vegetation on total thermal energy storage is negligible. Our results also showed that the bulk of the total thermal energy storage (G = Gs + Ga + Gc) in the surface energy balance was stored in the soil (Gs). In addition, we have also determined the crop coefficient (Kc) of pecan by combining the actual ET obtained from the OPEC method and potential ET (ET0) calculated using weather data in the surrounding area. Our average pecan Kc values were comparable with the ones reported by other researchers using different methods. We conclude that the OPEC energy balance method can be used to calculate Kc values for pecan whereby farmers and extension agents use the calculated Kc values in combination with ET0 to determine the consumptive use of pecan trees.

  5. The mapping of electronic energy distributions using experimental electron density.

    PubMed

    Tsirelson, Vladimir G

    2002-08-01

    It is demonstrated that the approximate kinetic energy density calculated using the second-order gradient expansion with parameters of the multipole model fitted to experimental structure factors reproduces the main features of this quantity in a molecular or crystal position space. The use of the local virial theorem provides an appropriate derivation of approximate potential energy density and electronic energy density from the experimental (model) electron density and its derivatives. Consideration of these functions is not restricted by the critical points in the electron density and provides a comprehensive characterization of bonding in molecules and crystals. PMID:12149553

  6. Symmetry Energy as a Function of Density and Mass

    SciTech Connect

    Danielewicz, Pawel; Lee, Jenny

    2007-10-26

    Energy in nuclear matter is, in practice, completely characterized at different densities and asymmetries, when the density dependencies of symmetry energy and of energy of symmetric matter are specified. The density dependence of the symmetry energy at subnormal densities produces mass dependence of nuclear symmetry coefficient and, thus, can be constrained by that latter dependence. We deduce values of the mass dependent symmetry coefficients, by using excitation energies to isobaric analog states. The coefficient systematic, for intermediate and high masses, is well described in terms of the symmetry coefficient values of a{sub a}{sup V} = (31.5-33.5) MeV for the volume coefficient and a{sub a}{sup S} = (9-12) MeV for the surface coefficient. These two further correspond to the parameter values describing density dependence of symmetry energy, of L{approx}95 MeV and K{sub sym}{approx}25 MeV.

  7. How many people actually see the price signal? Quantifying marketfailures in the end use of energy

    SciTech Connect

    Meier, Alan; Eide, Anita

    2007-09-01

    "Getting the price right" is a goal of many market-orientedenergy policies. However, there are situations where the consumer payingfor the energy is separate from the owner of the energy-using device.Economists call this a "principal agent problem". A team organised by theInternational Energy Agency examined seven end uses and one sector whereprincipal agent problems existed: refrigerators, water heating, spaceheating, vending machines, commercial HVAC, company cars, lighting, andfirms. These investigations took place in Australia, Japan, theNetherlands, Norway, and the United States. About 2 100 percent of theenergy consumed in the end uses examined was affected by principal agentproblems. The size (and sometimes even the existence) varied greatly fromone country to another but all countries had significant amounts ofenergy affected by principal agent problems. The presence of a marketfailure does not mean that energy use would fall substantially if thefailure were eliminated; however it does suggest that raising energyprices such as in the form of carbon taxes will not necessarily increaseefficiency investments.

  8. Theoretical study of lithium ionic conductors by electronic stress tensor density and electronic kinetic energy density.

    PubMed

    Nozaki, Hiroo; Fujii, Yosuke; Ichikawa, Kazuhide; Watanabe, Taku; Aihara, Yuichi; Tachibana, Akitomo

    2016-07-01

    We analyze the electronic structure of lithium ionic conductors, Li3PO4 and Li3PS4, using the electronic stress tensor density and kinetic energy density with special focus on the ionic bonds among them. We find that, as long as we examine the pattern of the eigenvalues of the electronic stress tensor density, we cannot distinguish between the ionic bonds and bonds among metalloid atoms. We then show that they can be distinguished by looking at the morphology of the electronic interface, the zero surface of the electronic kinetic energy density. © 2016 Wiley Periodicals, Inc. PMID:27232445

  9. Electrode/Dielectric Strip For High-Energy-Density Capacitor

    NASA Technical Reports Server (NTRS)

    Yen, Shiao-Ping S.

    1994-01-01

    Improved unitary electrode/dielectric strip serves as winding in high-energy-density capacitor in pulsed power supply. Offers combination of qualities essential for high energy density: high permittivity of dielectric layers, thinness, and high resistance to breakdown of dielectric at high electric fields. Capacitors with strip material not impregnated with liquid.

  10. High energy density propulsion systems and small engine dynamometer

    NASA Astrophysics Data System (ADS)

    Hays, Thomas

    2009-07-01

    Scope and Method of Study. This study investigates all possible methods of powering small unmanned vehicles, provides reasoning for the propulsion system down select, and covers in detail the design and production of a dynamometer to confirm theoretical energy density calculations for small engines. Initial energy density calculations are based upon manufacturer data, pressure vessel theory, and ideal thermodynamic cycle efficiencies. Engine tests are conducted with a braking type dynamometer for constant load energy density tests, and show true energy densities in excess of 1400 WH/lb of fuel. Findings and Conclusions. Theory predicts lithium polymer, the present unmanned system energy storage device of choice, to have much lower energy densities than other conversion energy sources. Small engines designed for efficiency, instead of maximum power, would provide the most advantageous method for powering small unmanned vehicles because these engines have widely variable power output, loss of mass during flight, and generate rotational power directly. Theoretical predictions for the energy density of small engines has been verified through testing. Tested values up to 1400 WH/lb can be seen under proper operating conditions. The implementation of such a high energy density system will require a significant amount of follow-on design work to enable the engines to tolerate the higher temperatures of lean operation. Suggestions are proposed to enable a reliable, small-engine propulsion system in future work. Performance calculations show that a mature system is capable of month long flight times, and unrefueled circumnavigation of the globe.

  11. A review of dietary energy density and obesity

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The role of dietary energy density (ED) in energy intake regulation and weight management remains controversial. Relationships between ED, energy intake, and body weight were determined in a review of pertinent studies examining the effects of ED on energy intake (EI) and/or body weight in non-elder...

  12. Update of axion CDM energy density

    SciTech Connect

    Huh, Ji-Haeng

    2008-11-23

    We update cosmological bound on axion model. The contribution from the anharmonic effect and the newly introduced initial overshoot correction are considered. We present an explicit formula for the axion relic density in terms of the QCD scale {lambda}{sub QCD}, the current quark masses m{sub q}'s and the Peccei-Quinn scale F{sub a}, including firstly introduced 1.85 factor which is from the initial overshoot.

  13. Design of the dual-buoy wave energy converter based on actual wave data of East Sea

    NASA Astrophysics Data System (ADS)

    Kim, Jeongrok; Kweon, Hyuck-Min; Jeong, Weon-Mu; Cho, Il-Hyoung; Cho, Hong-Yeon

    2015-07-01

    A new conceptual dual-buoy Wave Energy Converter (WEC) for the enhancement of energy extraction efficiency is suggested. Based on actual wave data, the design process for the suggested WEC is conducted in such a way as to ensure that it is suitable in real sea. Actual wave data measured in Korea's East Sea (position: 36.404 N° and 129.274 E°) from May 1, 2002 to March 29, 2005 were used as the input wave spectrum for the performance estimation of the dual-buoy WEC. The suggested WEC, a point absorber type, consists of two concentric floating circular cylinders (an inner and a hollow outer buoy). Multiple resonant frequencies in proposed WEC affect the Power Ttake-off (PTO) performance of the WEC. Based on the numerical results, several design strategies are proposed to further enhance the extraction efficiency, including intentional mismatching among the heave natural frequencies of dual buoys, the natural frequency of the internal fluid, and the peak frequency of the input wave spectrum.

  14. Longitudinal Density Modulation and Energy Conversion in Intense Beams

    SciTech Connect

    Harris, J; Neumann, J; Tian, K; O'Shea, P

    2006-02-17

    Density modulation of charged particle beams may occur as a consequence of deliberate action, or may occur inadvertently because of imperfections in the particle source or acceleration method. In the case of intense beams, where space charge and external focusing govern the beam dynamics, density modulation may under some circumstances be converted to velocity modulation, with a corresponding conversion of potential energy to kinetic energy. Whether this will occur depends on the properties of the beam and the initial modulation. This paper describes the evolution of discrete and continuous density modulations on intense beams, and discusses three recent experiments related to the dynamics of density-modulated electron beams.

  15. Ultra high energy density and fast discharge nanocomposite capacitors

    NASA Astrophysics Data System (ADS)

    Tang, Haixiong; Sodano, Henry A.

    2013-04-01

    Nanocomposites containing high dielectric permittivity ceramics embedded in high breakdown strength polymers are currently of considerable interest as a solution for the development of high energy density capacitors. However, the improvement of dielectric permittivity comes at expense of the breakdown strength leading to limit the final energy density. Here, an ultra-high energy density nanocomposite was fabricated based on high aspect ratio barium strontium titanate nanowires. The pyroelectric phase Ba0.2Sr0.8TiO3 was chosen for the nanowires combined with quenched PVDF to fabricate high energy density nanocomposite. The energy density with 7.5% Ba0.2Sr0.8TiO3 nanowires reached 14.86 J/cc at 450 MV/m, which represented a 42.9% increase in comparison to the PVDF with an energy density of 10.4 J/cc at the same electric field. The capacitors have 1138% greater than higher energy density than commercial biaxial oriented polypropylene capacitors (1.2 J/cc at 640). These results demonstrate that the high aspect ratio nanowires can be used to produce nanocomposite capacitors with greater performance than the neat polymers thus providing a novel process for the development of future pulsed-power capacitors.

  16. Energy Densities in the Strong-Interaction Limit of Density Functional Theory.

    PubMed

    Mirtschink, André; Seidl, Michael; Gori-Giorgi, Paola

    2012-09-11

    We discuss energy densities in the strong-interaction limit of density functional theory, deriving an exact expression within the definition (gauge) of the electrostatic potential of the exchange-correlation hole. Exact results for small atoms and small model quantum dots (Hooke's atoms) are compared with available approximations defined in the same gauge. The idea of a local interpolation along the adiabatic connection is discussed, comparing the energy densities of the Kohn-Sham, the physical, and the strong-interacting systems. We also use our results to analyze the local version of the Lieb-Oxford bound, widely used in the construction of approximate exchange-correlation functionals. PMID:26605721

  17. High-Energy-Density Electrolytic Capacitors

    NASA Technical Reports Server (NTRS)

    Yen, Shiao-Ping S.; Lewis, Carol R.

    1993-01-01

    Reductions in weight and volume make new application possible. Supercapacitors and improved ultracapacitors advanced electrolytic capacitors developed for use as electric-load-leveling devices in such applications as electric vehicle propulsion systems, portable power tools, and low-voltage pulsed power supplies. One primary advantage: offer power densities much higher than storage batteries. Capacitors used in pulse mode, with short charge and discharge times. Derived from commercially available ultracapacitors. Made of lightweight materials; incorporate electrode/electrolyte material systems capable of operation at voltages higher than previous electrode/electrolyte systems. By use of innovative designs and manufacturing processes, made in wide range of rated capacitances and in rated operating potentials ranging from few to several hundred volts.

  18. Postmortem validation of breast density using dual-energy mammography

    SciTech Connect

    Molloi, Sabee Ducote, Justin L.; Ding, Huanjun; Feig, Stephen A.

    2014-08-15

    Purpose: Mammographic density has been shown to be an indicator of breast cancer risk and also reduces the sensitivity of screening mammography. Currently, there is no accepted standard for measuring breast density. Dual energy mammography has been proposed as a technique for accurate measurement of breast density. The purpose of this study is to validate its accuracy in postmortem breasts and compare it with other existing techniques. Methods: Forty postmortem breasts were imaged using a dual energy mammography system. Glandular and adipose equivalent phantoms of uniform thickness were used to calibrate a dual energy basis decomposition algorithm. Dual energy decomposition was applied after scatter correction to calculate breast density. Breast density was also estimated using radiologist reader assessment, standard histogram thresholding and a fuzzy C-mean algorithm. Chemical analysis was used as the reference standard to assess the accuracy of different techniques to measure breast composition. Results: Breast density measurements using radiologist reader assessment, standard histogram thresholding, fuzzy C-mean algorithm, and dual energy were in good agreement with the measured fibroglandular volume fraction using chemical analysis. The standard error estimates using radiologist reader assessment, standard histogram thresholding, fuzzy C-mean, and dual energy were 9.9%, 8.6%, 7.2%, and 4.7%, respectively. Conclusions: The results indicate that dual energy mammography can be used to accurately measure breast density. The variability in breast density estimation using dual energy mammography was lower than reader assessment rankings, standard histogram thresholding, and fuzzy C-mean algorithm. Improved quantification of breast density is expected to further enhance its utility as a risk factor for breast cancer.

  19. Spin constraints on nuclear energy density functionals

    NASA Astrophysics Data System (ADS)

    Robledo, L. M.; Bernard, R. N.; Bertsch, G. F.

    2014-02-01

    The Gallagher-Moszkowski rule in the spectroscopy of odd-odd nuclei imposes a new spin constraint on the energy functionals for self-consistent mean field theory. The commonly used parametrization of the effective three-body interaction in the Gogny and Skyrme families of energy functionals is ill suited to satisfy the spin constraint. In particular, the Gogny parametrization of the three-body interaction has the spin dependence opposite to that required by the observed spectra. The two-body part has a correct sign, but in combination the rule is violated as often as not. We conclude that a new functional form is needed for the effective three-body interaction that can take into better account the different spin-isospin channels of the interaction.

  20. Assessing daily actual evapotranspiration through energy balance: an experiment to evaluate the selfpreservation hypothesis with acquisition time

    NASA Astrophysics Data System (ADS)

    Maltese, A.; Capodici, F.; Ciraolo, G.; La Loggia, G.; Rallo, G.

    2013-10-01

    An operational use of the actual evapotranspiration estimates requires the integration from instantaneous to daily values. This can commonly be achieved under the hypothesis of daytime self-preservation of the evaporative fraction. In this study, it has been evaluated the effect of this assumption on the assessment of daily evapotranspiration from proximity sensing images acquired at hourly intervals over a homogeneous olive groove. Results have been validated by comparison with observations made by a micrometeorological (EC-flux tower) and an eco-physiological (sap flux) sensor. SEBAL model has been applied to thermal and multispectral images acquired during a clear day on August 2009 trough a FLIR A320G thermal camera and a Tetracam MCA II multispectral camera, installed on a tethered helium balloon. Thermal and multispectral images were characterized by very high spatial resolution. This experiment aims to analyze two effects: 1) the consistency of the self-preservation hypothesis for daily estimates of the actual evapotranspiration from hourly assessments at different times of the day; 2) the effects of the spatial resolution on the performances of the energy balance model. To evaluate the effects of the spatial resolution, semi-hourly observations made by a flux tower and sap-flow measures were compared to the evapotranspiration estimates performed using downscaled images at resolutions close to canopy sizes (2, 5 and 10 m). Results show that the best estimates are obtained with a spatial resolution comparable to the average size of the canopy with images taken approximately at 10 UTC.

  1. An exposition on Friedmann cosmology with negative energy densities

    NASA Astrophysics Data System (ADS)

    Nemiroff, Robert J.; Joshi, Ravi; Patla, Bijunath R.

    2015-06-01

    How would negative energy density affect a classic Friedmann cosmology? Although never measured and possibly unphysical, certain realizations of quantum field theories leaves the door open for such a possibility. In this paper we analyze the evolution of a universe comprising varying amounts of negative energy forms. Negative energy components have negative normalized energy densities, Ω < 0. They include negative phantom energy with an equation of state parameter w < -1, negative cosmological constant: w=-1, negative domain walls: w = -2/3, negative cosmic strings: w=-1/3, negative mass: w = 0, negative radiation: w = 1/3 and negative ultralight: w > 1/3. Assuming that such energy forms generate pressure like perfect fluids, the attractive or repulsive nature of negative energy components are reviewed. The Friedmann equation is satisfied only when negative energy forms are coupled to a greater magnitude of positive energy forms or positive curvature. We show that the solutions exhibit cyclic evolution with bounces and turnovers.The future and fate of such universes in terms of curvature, temperature, acceleration, and energy density are reviewed. The end states are dubbed ``big crunch," `` big void," or ``big rip" and further qualified as ``warped",``curved", or ``flat",``hot" versus ``cold", ``accelerating" versus ``decelerating" versus ``coasting". A universe that ends by contracting to zero energy density is termed ``big poof." Which contracting universes ``bounce" in expansion and which expanding universes ``turnover" into contraction are also reviewed.

  2. Negative vacuum energy densities and the causal diamond measure

    SciTech Connect

    Salem, Michael P.

    2009-07-15

    Arguably a major success of the landscape picture is the prediction of a small, nonzero vacuum energy density. The details of this prediction depend in part on how the diverging spacetime volume of the multiverse is regulated, a question that remains unresolved. One proposal, the causal diamond measure, has demonstrated many phenomenological successes, including predicting a distribution of positive vacuum energy densities in good agreement with observation. In the string landscape, however, the vacuum energy density is expected to take positive and negative values. We find the causal diamond measure gives a poor fit to observation in such a landscape - in particular, 99.6% of observers in galaxies seemingly just like ours measure a vacuum energy density smaller than we do, most of them measuring it to be negative.

  3. Vacuum Casimir energy densities and field divergences at boundaries

    NASA Astrophysics Data System (ADS)

    Bartolo, Nicola; Butera, Salvatore; Lattuca, Margherita; Passante, Roberto; Rizzuto, Lucia; Spagnolo, Salvatore

    2015-06-01

    We consider and review the emergence of singular field fluctuations or energy densities at sharp boundaries or point-like field sources in the vacuum. The presence of singular energy densities of a field may be relevant from a conceptual point of view, because they contribute to the self-energy of the system. They could also generate significant gravitational effects. We first consider the case of the interface between a metallic boundary and the vacuum, and obtain the structure of the singular electric and magnetic energy densities at the interface through an appropriate limit from a dielectric to an ideal conductor. Then, we consider the case of a nondispersive and nondissipative point-like source of the electromagnetic field, described by its polarizability, and show that also in this case the electric and magnetic energy densities show a singular structure at the source position. We discuss how, in both cases, these singularities give an essential contribution to the electromagnetic self-energy of the system; moreover, they solve an apparent inconsistency between the space integral of the field energy density and the average value of the field Hamiltonian. The singular behavior we find is softened, or even eliminated, for boundaries fluctuating in space and for extended field sources. We discuss in detail the case in which a reflecting boundary is not fixed in space but is allowed to move around an equilibrium position, under the effect of quantum fluctuations of its position. Specifically, we consider the simple case of a 1D massless scalar field in a cavity with one fixed and one mobile wall described quantum-mechanically. We investigate how the possible motion of the wall changes the vacuum fluctuations and the energy density of the field, compared with the fixed-wall case. Also, we explicitly show how the fluctuating motion of the wall smears out the singular behaviour of the field energy density at the boundary.

  4. Mabolizable energy differences between values calculated using energy conversion factors and actual values determined by metabolic study of Korean starch foods.

    PubMed

    Kim, Eunmi; Choi, Jinho; Kim, Hyejin

    2014-04-01

    This study was conducted to compare the metabolizable energies of Korean starch foods by an animal metabolic study with those calculated using well-known energy conversion factors. There were 12 experimental diets (that is, 7 Korean foods, 3 Western foods, and 2 control foods): barley, brown rice, laver-rolled rice, rice mixed with vegetables and meat, seafood noodle soup, rice cake soup, rice cake in hot pepper paste, pizza, hamburger, spaghetti, basal diet, and glucose. Each diet comprised 70% basal diet and 30% experimental food. After 3 d of adaptation, a metabolic trial was performed for 4 d. The apparent metabolizable energy of pizza, hamburger, spaghetti, and rice cake soup were significantly higher than that of the basal diet group (P < 0.05). For barley, brown rice, laver-rolled rice, rice mixed with vegetables and meat, and seafood noodle soup, the differences between the actual and calculated energies were 8.7%, 13.3%, 4.5%, 17.2%, and 4.1%, respectively, and the actual energy contents were lower than those calculated using the Atwater conversion factor. The results of this study show that the energy contents of Korean foods are significantly different from those calculated using the conversion factors based on the food composition. Therefore, because Korean starch foods are considered to be calorie-rich based on calculations, their energy contents can be accurately determined only by animal experiments. PMID:24621178

  5. Validation of an improved energy balance model to estimate actual evapotranspiration in irrigated cotton ecosystems of Central Asia

    NASA Astrophysics Data System (ADS)

    Knoefel, Patrick; Conrad, Christopher; Falk, Ulrike; Bauer-Marschallinger, Bernhard

    2014-05-01

    The understanding of the hydrological and the energy cycles are essential in order to describe the complex interactions within the climate system of the earth. Being recognized as an essential component of both the water and the energy cycle, reliable estimation of actual evapotranspiration and its spatial distribution is one outstanding challenge in this context. For instance, in irrigation systems of arid regions, artificial locations of evapotranspiration have been created. An in-depth process understanding is of paramount importance, as irrigated agriculture consumes about 70 % of the available freshwater resources worldwide, with a significant but unsatisfyingly quantified impact on the water cycle, especially on regional scale. Moreover, an exact quantification of ET inside these artificial ecosystems enables assessments of crop water consumptions and hence about water use efficiency (WUE). The withdrawal of water for agricultural use in the countries of Central Asia is more than 90%. Khorezm region in Uzbekistan is a case study region for the problems of irrigated agriculture in CA. For Khorezm the seasonal actual ET was calculated for the years 2003 - 2010 using the partly modified surface energy balance algorithm for land (SEBAL). SEBAL was implemented based on MODIS time series to calculate the energy balance components like net radiation (Rn), sensible heat (H), latent heat (LE), and soil heat flux (G). Whilst SEBAL is using an empirical equation for estimating G, a more physically based method was introduced in this study. This method uses microwave soil moisture products (ASAR-SSM and ASCAT-SSM) as additional input information. The modelled energy balance components were intensively validated by field measurements with an eddy covariance system and soil sensors. For turbulent heat fluxes the RMSE is about 40 W/m² for H and 80 W/m² for LE with a coefficient of determination (r²) of 0.64 for H and 0.52 for LE. Soil heat flux estimation could be

  6. Analytical gradients for excitation energies from frozen-density embedding.

    PubMed

    Kovyrshin, Arseny; Neugebauer, Johannes

    2016-08-21

    The formulation of analytical excitation-energy gradients from time-dependent density functional theory within the frozen-density embedding framework is presented. In addition to a comprehensive mathematical derivation, we discuss details of the numerical implementation in the Slater-function based Amsterdam Density Functional (ADF) program. Particular emphasis is put on the consistency in the use of approximations for the evaluation of second- and third-order non-additive kinetic-energy and exchange-correlation functional derivatives appearing in the final expression for the excitation-energy gradient. We test the implementation for different chemical systems in which molecular excited-state potential-energy curves are affected by another subsystem. It is demonstrated that the analytical implementation for the evaluation of excitation-energy gradients yields results in close agreement with data from numerical differentiation. In addition, we show that our analytical results are numerically more stable and thus preferable over the numerical ones. PMID:26996970

  7. High Energy Density Regenerative Fuel Cell Systems for Terrestrial Applications

    NASA Technical Reports Server (NTRS)

    Burke, Kenneth A.

    1999-01-01

    Regenerative Fuel Cell System (RFCS) technology for energy storage has been a NASA power system concept for many years. Compared to battery-based energy storage systems, RFCS has received relatively little attention or resources for development because the energy density and electrical efficiency were not sufficiently attractive relative to advanced battery systems. Even today, RFCS remains at a very low technology readiness level (TRL of about 2 indicating feasibility has been demonstrated). Commercial development of the Proton Exchange Membrane (PEM) fuel cells for automobiles and other terrestrial applications and improvements in lightweight pressure vessel design to reduce weight and improve performance make possible a high energy density RFCS energy storage system. The results from this study of a lightweight RFCS energy storage system for a remotely piloted, solar-powered, high altitude aircraft indicate an energy density up to 790 w-h/kg with electrical efficiency of 53.4% is attainable. Such an energy storage system would allow a solar-powered aircraft to carry hundreds of kilograms of payload and remain in flight indefinitely for use in atmospheric research, earth observation, resource mapping. and telecommunications. Future developments in the areas of hydrogen and oxygen storage, pressure vessel design, higher temperature and higher- pressure fuel cell operation, unitized regenerative fuel cells, and commercial development of fuel cell technology will improve both the energy density and electrical efficiency of the RFCS.

  8. Hybrid system for rechargeable magnesium battery with high energy density.

    PubMed

    Chang, Zheng; Yang, Yaqiong; Wang, Xiaowei; Li, Minxia; Fu, Zhengwen; Wu, Yuping; Holze, Rudolf

    2015-01-01

    One of the main challenges of electrical energy storage (EES) is the development of environmentally friendly battery systems with high safety and high energy density. Rechargeable Mg batteries have been long considered as one highly promising system due to the use of low cost and dendrite-free magnesium metal. The bottleneck for traditional Mg batteries is to achieve high energy density since their output voltage is below 2.0 V. Here, we report a magnesium battery using Mg in Grignard reagent-based electrolyte as the negative electrode, a lithium intercalation compound in aqueous solution as the positive electrode, and a solid electrolyte as a separator. Its average discharge voltage is 2.1 V with stable discharge platform and good cycling life. The calculated energy density based on the two electrodes is high. These findings open another door to rechargeable magnesium batteries. PMID:26173624

  9. Hybrid system for rechargeable magnesium battery with high energy density

    PubMed Central

    Chang, Zheng; Yang, Yaqiong; Wang, Xiaowei; Li, Minxia; Fu, Zhengwen; Wu, Yuping; Holze, Rudolf

    2015-01-01

    One of the main challenges of electrical energy storage (EES) is the development of environmentally friendly battery systems with high safety and high energy density. Rechargeable Mg batteries have been long considered as one highly promising system due to the use of low cost and dendrite-free magnesium metal. The bottleneck for traditional Mg batteries is to achieve high energy density since their output voltage is below 2.0 V. Here, we report a magnesium battery using Mg in Grignard reagent-based electrolyte as the negative electrode, a lithium intercalation compound in aqueous solution as the positive electrode, and a solid electrolyte as a separator. Its average discharge voltage is 2.1 V with stable discharge platform and good cycling life. The calculated energy density based on the two electrodes is high. These findings open another door to rechargeable magnesium batteries. PMID:26173624

  10. On the existence of free energy densities in non-uniform fluids

    NASA Astrophysics Data System (ADS)

    Lovett, Ronald; Baus, Marc

    1992-02-01

    The perception that unambigous constructions of local thermodynamic quantities cannot be given in equilibrium but non-uniform fluids has grown out of the recognition that many distinct thermodynamic fields satisfy the existing prescriptions for these quantities. That is, the existing prescriptions for thermodynamic fields underdetermine these quantities. It is shown that in many important cases, however, the requirement that thermodynamic consistency - the hallmark of classical thermodynamics-hold on all spatial scales does lead to a complete specification of free energy densities. The development presented requires-as in thermodynamics in general-a clear view of what fields actually fix the state of a non-uniform system. In the absence of a clear experimental foundation, the present development is built upon the statistical mechanical framework supporting density functional methods. It is noted that the identification of the free energy density as a stress tensor component is clouded by the fact that the traditional stress tensor formulation actually underdetermines a stress tensor. While this confusion should have no thermodynamic consequences it is also noted that the boundary conditions which play an essential role in constructing a thermodynamically meaningful stress tensor are not explicitly stated in general.

  11. Internal wave pressure, velocity, and energy flux from density perturbations

    NASA Astrophysics Data System (ADS)

    Allshouse, Michael R.; Lee, Frank M.; Morrison, Philip J.; Swinney, Harry L.

    2016-05-01

    Determination of energy transport is crucial for understanding the energy budget and fluid circulation in density varying fluids such as the ocean and the atmosphere. However, it is rarely possible to determine the energy flux field J =p u , which requires simultaneous measurements of the pressure and velocity perturbation fields p and u , respectively. We present a method for obtaining the instantaneous J (x ,z ,t ) from density perturbations alone: A Green's function-based calculation yields p ; u is obtained by integrating the continuity equation and the incompressibility condition. We validate our method with results from Navier-Stokes simulations: The Green's function method is applied to the density perturbation field from the simulations and the result for J is found to agree typically to within 1% with J computed directly using p and u from the Navier-Stokes simulation. We also apply the Green's function method to density perturbation data from laboratory schlieren measurements of internal waves in a stratified fluid and the result for J agrees to within 6 % with results from Navier-Stokes simulations. Our method for determining the instantaneous velocity, pressure, and energy flux fields applies to any system described by a linear approximation of the density perturbation field, e.g., to small-amplitude lee waves and propagating vertical modes. The method can be applied using our matlab graphical user interface EnergyFlux.

  12. Surface energy balance and actual evapotranspiration of the transboundary Indus Basin estimated from satellite measurements and the ETLook model

    NASA Astrophysics Data System (ADS)

    Bastiaanssen, W. G. M.; Cheema, M. J. M.; Immerzeel, W. W.; Miltenburg, I. J.; Pelgrum, H.

    2012-11-01

    The surface energy fluxes and related evapotranspiration processes across the Indus Basin were estimated for the hydrological year 2007 using satellite measurements. The new ETLook remote sensing model (version 1) infers information on actual Evaporation (E) and actual Transpiration (T) from combined optical and passive microwave sensors, which can observe the land-surface even under persistent overcast conditions. A two-layer Penman-Monteith equation was applied for quantifying soil and canopy evaporation. The novelty of the paper is the computation of E and T across a vast area (116.2 million ha) by using public domain microwave data that can be applied under all weather conditions, and for which no advanced input data are required. The average net radiation for the basin was estimated as being 112 Wm-2. The basin average sensible, latent and soil heat fluxes were estimated to be 80, 32, and 0 Wm-2, respectively. The average evapotranspiration (ET) and evaporative fraction were 1.2 mm d-1 and 0.28, respectively. The basin wide ET was 496 ± 16.8 km3 yr-1. Monte Carlo analysis have indicated 3.4% error at 95% confidence interval for a dominant land use class. Results compared well with previously conducted soil moisture, lysimeter and Bowen ratio measurements at field scale (R2 = 0.70; RMSE = 0.45 mm d-1; RE = -11.5% for annual ET). ET results were also compared against earlier remote sensing and modeling studies for various regions and provinces in Pakistan (R2 = 0.76; RMSE = 0.29 mmd-1; RE = 6.5% for annual ET). The water balance for all irrigated areas together as one total system in Pakistan and India (26.02 million ha) show a total ET value that is congruent with the ET value from the ETLook surface energy balance computations. An unpublished validation of the same ETLook model for 23 jurisdictional areas covering the entire Australian continent showed satisfactory results given the quality of the watershed data and the diverging physiographic and climatic

  13. High Energy Density Physics on LULI2000 Laser Facility

    NASA Astrophysics Data System (ADS)

    Koenig, M.; Benuzzi-Mounaix, A.; Ozaki, N.; Ravasio, A.; Vinci, T.; Lepape, S.; Tanaka, K.; Riley, D.

    2006-07-01

    We present here a summary of some High Density Energy Physics experiments performed on the new facility LULI 2000. First, different flyer plate targets scheme have been tested loading shock in fused-quartz plate. Temperature data along the Hugoniot curve have been obtained. Second, a strongly coupled and degenerated Aluminium plasma has been probed by X-ray Thomson scattering. Compton shift from electrons has been observed in various density conditions.

  14. Molecular partitioning based on the kinetic energy density

    NASA Astrophysics Data System (ADS)

    Noorizadeh, Siamak

    2016-05-01

    Molecular partitioning based on the kinetic energy density is performed to a number of chemical species, which show non-nuclear attractors (NNA) in their gradient maps of the electron density. It is found that NNAs are removed using this molecular partitioning and although the virial theorem is not valid for all of the basins obtained in the being used AIM, all of the atoms obtained using the new approach obey this theorem. A comparison is also made between some atomic topological parameters which are obtained from the new partitioning approach and those calculated based on the electron density partitioning.

  15. Fourth International Conference on High Energy Density Physics

    SciTech Connect

    Beg, Farhat

    2015-01-06

    The Fourth International Conference on High Energy Density Physics (ICHED 2013) was held in Saint Malo, France, at the Palais du Grand Large on 25-28 June 2013 (http://web.luli.polytechnique.fr/ICHED2013/). This meeting was the fourth in a series which was first held in 2008. This conference covered all the important aspects of High Energy Density Physics including fundamental topics from strong-field physics to creating new states of matter (including radiation-dominated, high-pressure quantum and relativistic plasmas) and ultra-fast lattice dynamics on the timescale of atomic transitions.

  16. High-Energy-Density Cost-Effective Graphene Supercapacitors

    NASA Astrophysics Data System (ADS)

    Samuilov, Vladimir; Ying Mu, Ying; Hedayat, Nader; Solovyov, Vyacheslav; Sensor CAT at Stony Brook Team

    We introduce a cost-effective graphene platelet composite material as a replacement of an expensive reduced graphene oxide for electrodes in high energy density supercapacitors. We have tested a low size supercapacitor prototypes with the graphene platelets electrodes and newly developed polymer-gel Li + ion electrolyte. We discuss the ways how to increase the capacitance and the energy densities of the supercapacitor significantly. A working prototype for testing the concept of the high voltage supercapacitor has been developed as well. The first test done up to 10 V showed excellent performance of the multy-cell multi-layer high voltage test assembly.

  17. High Energy Density Sciences with High Power Lasers at SACLA

    NASA Astrophysics Data System (ADS)

    Kodama, Ryosuke

    2013-10-01

    One of the interesting topics on high energy density sciences with high power lasers is creation of extremely high pressures in material. The pressures of more than 0.1 TPa are the energy density corresponding to the chemical bonding energy, resulting in expectation of dramatic changes in the chemical reactions. At pressures of more than TPa, most of material would be melted on the shock Hugoniot curve. However, if the temperature is less than 1eV or lower than a melting point at pressures of more than TPa, novel solid states of matter must be created through a pressured phase transition. One of the interesting materials must be carbon. At pressures of more than TPa, the diamond structure changes to BC and cubic at more than 3TPa. To create such novel states of matter, several kinds of isentropic-like compression techniques are being developed with high power lasers. To explore the ``Tera-Pascal Science,'' now we have a new tool which is an x-ray free electron laser as well as high power lasers. The XFEL will clear the details of the HED states and also efficiently create hot dense matter. We have started a new project on high energy density sciences using an XFEL (SACLA) in Japan, which is a HERMES (High Energy density Revolution of Matter in Extreme States) project.

  18. Looking for high energy density compounds among polynitraminepurines.

    PubMed

    Yan, Ting; Sun, Guangdong; Chi, Weijie; Li, Butong; Wu, Haishun

    2013-09-01

    A series of purine derivatives with nitramine groups are calculated by using density functional theory (DFT). The molecular theory density, heats of formation, bond dissociation energies and detonation performance are investigated at DFT-B3LYP/6-311G** level. The isodesmic reaction method is employed to calculate the HOFs of the energies obtained from electronic structure calculations. Results show that the position of nitramine groups can influence the values of HOFs. The bond dissociation energies and the impact sensitivity are analyzed to investigate the thermal stability of the purine derivatives. The calculated bond dissociation energies of ring-NHNO2 and NH-NO2 bond show that the NH-NO2 bond should be the trigger bond in pyrolysis processes. The H50 of most compounds are larger than that of CL-20 and RDX. PMID:23708652

  19. Vacuum energy density kicked by the electroweak crossover

    SciTech Connect

    Klinkhamer, F. R.; Volovik, G. E.

    2009-10-15

    Using q-theory, we show that the electroweak crossover can generate a remnant vacuum energy density {lambda}{approx}E{sub ew}{sup 8}/E{sub Planck}{sup 4}, with effective electroweak energy scale E{sub ew}{approx}10{sup 3} GeV and reduced Planck-energy scale E{sub Planck}{approx}10{sup 18} GeV. The obtained expression for the effective cosmological constant {lambda} may be a crucial input for the suggested solution by Arkani-Hamed et al. of the triple cosmic coincidence puzzle (why the orders of magnitude of the energy densities of vacuum, matter, and radiation are approximately the same in the present Universe)

  20. Theoretically predicted Fox-7 based new high energy density molecules

    NASA Astrophysics Data System (ADS)

    Ghanta, Susanta

    2016-08-01

    Computational investigation of CHNO based high energy density molecules (HEDM) are designed with FOX-7 (1, 1-dinitro 2, 2-diamino ethylene) skeleton. We report structures, stability and detonation properties of these new molecules. A systematic analysis is presented for the crystal density, activation energy for nitro to nitrite isomerisation and the C-NO2 bond dissociation energy of these molecules. The Atoms in molecules (AIM) calculations have been performed to interpret the intra-molecular weak H-bonding interactions and the stability of C-NO2 bonds. The structure optimization, frequency and bond dissociation energy calculations have been performed at B3LYP level of theory by using G03 quantum chemistry package. Some of the designed molecules are found to be more promising HEDM than FOX-7 molecule, and are proposed to be candidate for synthetic purpose.

  1. Determination of the nuclear level density at high excitation energy

    SciTech Connect

    Chbihi, A.; Sobotka, L.G.; Nicolis, N.G.; Sarantites, D.G.; Stracener, D.W.; Majka, Z. ); Hensley, D.C.; Beene, J.R.; Halbert, M.L. )

    1991-02-01

    Evaporation simulations are presented to illustrate the problems associated with the determination of the nuclear level density constant at high excitation energy from evaporation spectra. The methods of using either the total (whole chain) spectra or the difference (from two different initial excitation energies) spectra are discussed. Data from the study of the reaction 701 MeV {sup 28}Si+{sup 100}Mo are presented and both methods are used to extract the level density constant. We find that in order to reproduce the slopes of the light particle spectra the level density constant must have a value near 1/10{ital A}-- 1 / 11 {ital A} for excited nuclei with statistical temperatures in the range of 3.5 to 5.5 MeV. This presumes that the only parameter adjustment required to treat the decay of highly exited nuclei is the level density constant. If this is so, the shapes of the evaporation spectra imply a reduction in the level density constant from the value required to explain the decay of less highly excited nuclei, a conclusion reached by others. However, the reduced level density constant leads to an overproduction of deuterons and tritons. This suggests that a more complicated set of parameter adjustments may be required to treat the decay of highly excited nuclei.

  2. Improved DFT Potential Energy Surfaces via Improved Densities.

    PubMed

    Kim, Min-Cheol; Park, Hansol; Son, Suyeon; Sim, Eunji; Burke, Kieron

    2015-10-01

    Density-corrected DFT is a method that cures several failures of self-consistent semilocal DFT calculations by using a more accurate density instead. A novel procedure employs the Hartree-Fock density to bonds that are more severely stretched than ever before. This substantially increases the range of accurate potential energy surfaces obtainable from semilocal DFT for many heteronuclear molecules. We show that this works for both neutral and charged molecules. We explain why and explore more difficult cases, for example, CH(+), where density-corrected DFT results are even better than sophisticated methods like CCSD. We give a simple criterion for when DC-DFT should be more accurate than self-consistent DFT that can be applied for most cases. PMID:26722874

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

    SciTech Connect

    Aslanyan, V.; Tallents, G. J.

    2014-06-15

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

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

    NASA Astrophysics Data System (ADS)

    Aslanyan, V.; Tallents, G. J.

    2014-06-01

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

  5. Collapsing Bubble in Metal for High Energy Density Physics Study

    SciTech Connect

    Ng, S F; Barnard, J J; Leung, P T; Yu, S S

    2011-04-13

    This paper presents a new idea to produce matter in the high energy density physics (HEDP) regime in the laboratory using an intense ion beam. A gas bubble created inside a solid metal may collapse by driving it with an intense ion beam. The melted metal will compress the gas bubble and supply extra energy to it. Simulations show that the spherical implosion ratio can be about 5 and at the stagnation point, the maximum density, temperature and pressure inside the gas bubble can go up to nearly 2 times solid density, 10 eV and a few megabar (Mbar) respectively. The proposed experiment is the first to permit access into the Mbar regime with existing or near-term ion facilities, and opens up possibilities for new physics gained through careful comparisons of simulations with measurements of quantities like stagnation radius, peak temperature and peak pressure at the metal wall.

  6. Design for a High Energy Density Kelvin-Helmholtz Experiment

    SciTech Connect

    Hurricane, O A

    2007-10-29

    While many high energy density physics (HEDP) Rayleigh-Taylor and Richtmyer-Meshkov instability experiments have been fielded as part of basic HEDP and astrophysics studies, not one HEDP Kelvin-Helmholtz (KH) experiment has been successfully performed. Herein, a design for a novel HEDP x-ray driven KH experiment is presented along with supporting radiation-hydrodynamic simulation and theory.

  7. New developments in the multiscale hybrid energy density computational method

    NASA Astrophysics Data System (ADS)

    Min, Sun; Shanying, Wang; Dianwu, Wang; Chongyu, Wang

    2016-01-01

    Further developments in the hybrid multiscale energy density method are proposed on the basis of our previous papers. The key points are as follows. (i) The theoretical method for the determination of the weight parameter in the energy coupling equation of transition region in multiscale model is given via constructing underdetermined equations. (ii) By applying the developed mathematical method, the weight parameters have been given and used to treat some problems in homogeneous charge density systems, which are directly related with multiscale science. (iii) A theoretical algorithm has also been presented for treating non-homogeneous systems of charge density. The key to the theoretical computational methods is the decomposition of the electrostatic energy in the total energy of density functional theory for probing the spanning characteristic at atomic scale, layer by layer, by which the choice of chemical elements and the defect complex effect can be understood deeply. (iv) The numerical computational program and design have also been presented. Project supported by the National Basic Research Program of China (Grant No. 2011CB606402) and the National Natural Science Foundation of China (Grant No. 51071091).

  8. Zinc-oxygen primary cell yields high energy density

    NASA Technical Reports Server (NTRS)

    Graff, C. B.

    1968-01-01

    Zinc-oxygen primary cell yields high energy density for battery used as an auxiliary power source in space vehicle systems. Maximum reliability and minimum battery weight is achieved by using a stacking configuration of 23 series-connected modules with 6 parallel-connected cells per module.

  9. Active minimization of energy density in three-dimensional enclosures

    NASA Technical Reports Server (NTRS)

    Sommerfeldt, Scott D.

    1996-01-01

    The objective of this study was to further investigate and develop a novel approach for actively controlling the sound field in enclosures that is based on the acoustic energy density. Typically the acoustic field in an enclosure has been controlled by minimizing the sum of the squared pressures from several microphones distributed throughout the enclosure. The approach investigated in this study involved minimizing the acoustic energy density at the sensor locations, rather than the squared pressure. Research previous to this study in a simple one-dimensional enclosure showed that improved global attenuation of the acoustic field is often obtained by minimizing the energy density, rather than the pressure. The current study built on the previous research by extending the method of controlling the acoustic energy density to three-dimensional enclosures. The study was intended to help establish if improved control can still be expected in a more general enclosure. The study was designed to be both analytical/numerical and experimental in nature.

  10. Quantum Chromodynamics and Nuclear Physics at Extreme Energy Density

    SciTech Connect

    Mueller, B.; Bass, S.A.; Chandrasekharan, S.; Mehen, T.; Springer, R.P.

    2005-11-07

    The report describes research in theoretical quantum chromodynamics, including effective field theories of hadronic interactions, properties of strongly interacting matter at extreme energy density, phenomenology of relativistic heavy ion collisions, and algorithms and numerical simulations of lattice gauge theory and other many-body systems.

  11. A novel high energy density rechargeable lithium/air battery.

    PubMed

    Zhang, Tao; Imanishi, Nobuyuki; Shimonishi, Yuta; Hirano, Atsushi; Takeda, Yasuo; Yamamoto, Osamu; Sammes, Nigel

    2010-03-14

    A novel rechargeable lithium/air battery was fabricated, which consisted of a water-stable multilayer Li-metal anode, acetic acid-water electrolyte, and a fuel-cell analogous air-diffusion cathode and possessed a high energy density of 779 W h kg(-1), twice that of the conventional graphite/LiCoO(2) cell. PMID:20177608

  12. Quantum inequality restrictions on negative energy densities in curved spacetimes

    NASA Astrophysics Data System (ADS)

    Pfenning, Michael John

    1998-10-01

    In quantum field theory, there exist states in which the expectation value of the energy density for a quantized field is negative. These negative energy densities lead to several problems such as the failure of the classical energy conditions, the production of closed timelike curves and faster than light travel, violations of the second law of thermodynamics, and the possible production of naked singularities. Although quantum field theory introduces negative energies, it also provides constraints in the form of quantum inequalities (QI's). These uncertainty principle- type relations limit the magnitude and duration of any negative energy. We derive a general form of the QI on the energy density for both the quantized scalar and electromagnetic fields in static curved spacetimes. In the case of the scalar field, the QI can be written as the Euclidean wave operator acting on the Euclidean Green's function. Additionally, a small distance expansion on the Green's function is used to derive the QI in the short sampling time limit. It is found that the QI in this limit reduces to the flat space form with subdominant correction terms which depend on the spacetime geometry. Several example spacetimes are studied in which exact forms of the QI's can be found. These include the three- and four-dimensional static Robertson-Walker spacetimes, flat space with perfectly reflecting mirrors, Rindler and static de Sitter space, and the spacetime outside a black hole. In all of the above cases, we find that the quantum inequalities give a lower limit on how much negative energy may be observed relative to the vacuum energy density of the spacetime. For the particular case of the black hole, it is found that the quantum inequality on the energy density is measured relative to the Boulware vacuum. Finally, the application of the quantum inequalities to the Alcubierre warp drive spacetime leads to strict constraints on the thickness of the negative energy region needed to maintain

  13. Single-point kinetic energy density functionals: A pointwise kinetic energy density analysis and numerical convergence investigation

    NASA Astrophysics Data System (ADS)

    Xia, Junchao; Carter, Emily A.

    2015-01-01

    We present a comprehensive study of single-point kinetic energy density functionals (KEDFs) to be used in orbital-free density functional theory (DFT) calculations. We first propose a form of KEDFs based on a pointwise Kohn-Sham (KS) kinetic energy density (KED) and electron localization function (ELF) analysis. We find that the ELF and modified enhancement factor have a very strong and transferable correlation with the reduced density in various bulk metals. The non-self-consistent kinetic energy errors predicted by our KEDF models are decreased greatly compared to previously reported generalized gradient approximation (GGA) KEDFs. Second, we perform self-consistent calculations with various single-point KEDFs and investigate their numerical convergence behavior. We find striking numerical instabilities for previous GGA KEDFs; most of the GGA KEDFs fail to converge and show unphysical densities during the optimization. In contrast, our KEDFs demonstrate stable convergence, and their self-consistent results of various bulk properties agree reasonably well with KSDFT. A further detailed KED analysis reveals an interesting bifurcation phenomenon in defective metals and alloys, which may shed light on directions for future KEDF development.

  14. A Coupled Remote Sensing and Simplified Surface Energy Balance Approach to Estimate Actual Evapotranspiration from Irrigated Fields

    PubMed Central

    Senay, Gabriel B.; Budde, Michael; Verdin, James P.; Melesse, Assefa M.

    2007-01-01

    Accurate crop performance monitoring and production estimation are critical for timely assessment of the food balance of several countries in the world. Since 2001, the Famine Early Warning Systems Network (FEWS NET) has been monitoring crop performance and relative production using satellite-derived data and simulation models in Africa, Central America, and Afghanistan where ground-based monitoring is limited because of a scarcity of weather stations. The commonly used crop monitoring models are based on a crop water-balance algorithm with inputs from satellite-derived rainfall estimates. These models are useful to monitor rainfed agriculture, but they are ineffective for irrigated areas. This study focused on Afghanistan, where over 80 percent of agricultural production comes from irrigated lands. We developed and implemented a Simplified Surface Energy Balance (SSEB) model to monitor and assess the performance of irrigated agriculture in Afghanistan using a combination of 1-km thermal data and 250-m Normalized Difference Vegetation Index (NDVI) data, both from the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor. We estimated seasonal actual evapotranspiration (ETa) over a period of six years (2000-2005) for two major irrigated river basins in Afghanistan, the Kabul and the Helmand, by analyzing up to 19 cloud-free thermal and NDVI images from each year. These seasonal ETa estimates were used as relative indicators of year-to-year production magnitude differences. The temporal water-use pattern of the two irrigated basins was indicative of the cropping patterns specific to each region. Our results were comparable to field reports and to estimates based on watershed-wide crop water-balance model results. For example, both methods found that the 2003 seasonal ETa was the highest of all six years. The method also captured water management scenarios where a unique year-to-year variability was identified in addition to water-use differences between

  15. A coupled remote sensing and simplified surface energy balance approach to estimate actual evapotranspiration from irrigated fields

    USGS Publications Warehouse

    Senay, G.B.; Budde, M.; Verdin, J.P.; Melesse, Assefa M.

    2007-01-01

    Accurate crop performance monitoring and production estimation are critical for timely assessment of the food balance of several countries in the world. Since 2001, the Famine Early Warning Systems Network (FEWS NET) has been monitoring crop performance and relative production using satellite-derived data and simulation models in Africa, Central America, and Afghanistan where ground-based monitoring is limited because of a scarcity of weather stations. The commonly used crop monitoring models are based on a crop water-balance algorithm with inputs from satellite-derived rainfall estimates. These models are useful to monitor rainfed agriculture, but they are ineffective for irrigated areas. This study focused on Afghanistan, where over 80 percent of agricultural production comes from irrigated lands. We developed and implemented a Simplified Surface Energy Balance (SSEB) model to monitor and assess the performance of irrigated agriculture in Afghanistan using a combination of 1-km thermal data and 250m Normalized Difference Vegetation Index (NDVI) data, both from the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor. We estimated seasonal actual evapotranspiration (ETa) over a period of six years (2000-2005) for two major irrigated river basins in Afghanistan, the Kabul and the Helmand, by analyzing up to 19 cloud-free thermal and NDVI images from each year. These seasonal ETa estimates were used as relative indicators of year-to-year production magnitude differences. The temporal water-use pattern of the two irrigated basins was indicative of the cropping patterns specific to each region. Our results were comparable to field reports and to estimates based on watershed-wide crop water-balance model results. For example, both methods found that the 2003 seasonal ETa was the highest of all six years. The method also captured water management scenarios where a unique year-to-year variability was identified in addition to water-use differences between

  16. Kinetic-energy density functional: Atoms and shell structure

    SciTech Connect

    Garcia-Gonzalez, P.; Alvarellos, J.E.; Chacon, E. |

    1996-09-01

    We present a nonlocal kinetic-energy functional which includes an anisotropic average of the density through a symmetrization procedure. This functional allows a better description of the nonlocal effects of the electron system. The main consequence of the symmetrization is the appearance of a clear shell structure in the atomic density profiles, obtained after the minimization of the total energy. Although previous results with some of the nonlocal kinetic functionals have given incipient structures for heavy atoms, only our functional shows a clear shell structure for most of the atoms. The atomic total energies have a good agreement with the exact calculations. Discussion of the chemical potential and the first ionization potential in atoms is included. The functional is also extended to spin-polarized systems. {copyright} {ital 1996 The American Physical Society.}

  17. Separating the Universe into real and fake energy densities

    NASA Astrophysics Data System (ADS)

    Hu, Wayne; Chiang, Chi-Ting; Li, Yin; LoVerde, Marilena

    2016-07-01

    The separate universe technique provides a means of establishing consistency relations between short-wavelength observables and the long-wavelength matter density fluctuations within which they evolve by absorbing the latter into the cosmological background. We extend it to cases where nongravitational forces introduce a Jeans scale in other species like dynamical dark energy or massive neutrinos. The technique matches the synchronous gauge matter density fluctuations to the local expansion using the acceleration equation and accounts for the temporal nonlocality and scale dependence of the long-wavelength response of small scale matter observables, e.g., the nonlinear power spectrum, halo abundance and the implied halo bias, and N -point correlation functions. Above the Jeans scale, the local Friedmann equation relates the expansion to real energy densities and a curvature that is constant in comoving coordinates. Below the Jeans scale, the curvature evolves and acts like a fake density component. In all cases, the matter evolution on small scales is correctly modeled as we illustrate using scalar field dark energy with adiabatic or isocurvature initial conditions across the Jeans scale set by its finite sound speed.

  18. High energy density interpenetrating networks from ionic networks and silicone

    NASA Astrophysics Data System (ADS)

    Yu, Liyun; Madsen, Frederikke B.; Hvilsted, Søren; Skov, Anne L.

    2015-04-01

    The energy density of dielectric elastomers (DEs) is sought increased for better exploitation of the DE technology since an increased energy density means that the driving voltage for a certain strain can be lowered in actuation mode or alternatively that more energy can be harvested in generator mode. One way to increase the energy density is to increase dielectric permittivity of the elastomer. A novel silicone elastomer system with high dielectric permittivity was prepared through the development of interpenetrating networks from ionically assembled silicone polymers and covalently crosslinked silicones. The system has many degrees of freedom since the ionic network is formed from two polymers (amine and carboxylic acid functional, respectively) of which the chain lengths can be varied, as well as the covalent silicone elastomer with many degrees of freedom arising from amongst many the varying content of silica particles. A parameter study is performed to elucidate which compositions are most favorable for the use as dielectric elastomers. The elastomers were furthermore shown to be self-repairing upon electrical breakdown.

  19. Pulse Power Capability Of High Energy Density Capacitors Based on a New Dielectric Material

    NASA Technical Reports Server (NTRS)

    Winsor, Paul; Scholz, Tim; Hudis, Martin; Slenes, Kirk M.

    1999-01-01

    A new dielectric composite consisting of a polymer coated onto a high-density metallized Kraft has been developed for application in high energy density pulse power capacitors. The polymer coating is custom formulated for high dielectric constant and strength with minimum dielectric losses. The composite can be wound and processed using conventional wound film capacitor manufacturing equipment. This new system has the potential to achieve 2 to 3 J/cu cm whole capacitor energy density at voltage levels above 3.0 kV, and can maintain its mechanical properties to temperatures above 150 C. The technical and manufacturing development of the composite material and fabrication into capacitors are summarized in this paper. Energy discharge testing, including capacitance and charge-discharge efficiency at normal and elevated temperatures, as well as DC life testing were performed on capacitors manufactured using this material. TPL (Albuquerque, NM) has developed the material and Aerovox (New Bedford, MA) has used the material to build and test actual capacitors. The results of the testing will focus on pulse power applications specifically those found in electro-magnetic armor and guns, high power microwave sources and defibrillators.

  20. Energy density in cafeteria diet induced hyperphagia in the rat.

    PubMed

    Shafat, Amir; Murray, Brenda; Rumsey, David

    2009-02-01

    Rats that are fed cafeteria diet (CD) are a widely used model of obesity. Presenting a varied and energy-dense diet often leads to hyperphagia and weight gain. However, the exact macronutrient composition of ingested food remains difficult to measure accurately. The current investigation aims to improve the accuracy of food intake calculations using a novel compensation for water evaporation, and to examine the role of energy density in CD-induced hyperphagia. Seven rats were presented daily with four foods, on rotation from a list of 36 different items, for a period of 43 days and compared to chow-fed controls (n=6). Correcting for evaporation corrected an overestimation by 8% of energy intake in rats fed CD. Rats consumed 25% more food by weight when fed CD as compared to controls. Similar to human studies, exposure to CD resulted in a 58% increase in energy intake. Energy density was positively correlated with energy intake in rats fed CD. Body weight gain was significantly elevated from day 20 onwards, suggesting the onset of obesity. This study removes evaporation bias from measurements of food intake in CD and supports the conclusion that a varied, energetically dense diet induces hyperphagia and obesity in the rat. PMID:18680774

  1. Looking for high energy density compounds among polynitraminecubanes.

    PubMed

    Chi, Wei-Jie; Li, Lu-Lin; Li, Bu-Tong; Wu, Hai-Shun

    2013-02-01

    Based on fully optimized geometric structures at DFT-B3LYP/6-311G** level, we calculated electronic structures, heats of formation, strain energies, bond dissociation energies and detonation performance (detonation velocity and detonation pressure) for a series of polynitraminecubanes. Our results have shown that energy gaps of cubane derivatives are much higher than that of triaminotrinitrobenzene (TATB), which means that cubane derivatives may be more sensitive than TATB. Polynitraminecubanes have high and positive heats of formation, and a good linear relationship between heats of formation and nitramine group numbers was presented. As the number of nitramine groups in the molecule increases, the enthalpies of combustion values are increasingly negative, but the specific enthalpy of combustion values decreases. It is found that all cubane derivatives have high strain energies, which are affected by the number and position of nitramine group. The calculated bond dissociation energies of C-NHNO(2) and C-C bond show that the C-C bond should be the trigger bond in the pyrolysis process. It is found that detonation velocity (D), detonation pressure (P) and molecule density (ρ) have good linear relationship with substituented group numbers. Heptanitraminecubane and octanitraminecubane have good detonation performance over 1,3,5,7-tetranitro-1,3,5,7-tetraazacyclooctane (HMX), and they can be regarded as potential candidates of high energy density compounds (HEDCs). The results have not only shown that these compounds may be used as HEDCs, but also provide some useful information for further investigation. PMID:22961623

  2. Relaxor-ferroelectric superlattices: high energy density capacitors.

    PubMed

    Ortega, N; Kumar, A; Scott, J F; Chrisey, Douglas B; Tomazawa, M; Kumari, Shalini; Diestra, D G B; Katiyar, R S

    2012-11-01

    We report the breakdown electric field and energy density of laser ablated BaTiO(3)/Ba((1-x))Sr(x)TiO(3) (x = 0.7) (BT/BST) relaxor-ferroelectric superlattices (SLs) grown on (100) MgO single crystal substrates. The dielectric constant shows a frequency dispersion below the dielectric maximum temperature (T(m)) with a merger above T(m) behaving similarly to relaxors. It also follows the basic criteria of relaxor ferroelectrics such as low dielectric loss over wide temperature and frequency, and 50 K shift in T(m) with change in probe frequency; the loss peaks follow a similar trend to the dielectric constant except that they increase with increase in frequency (~40 kHz), and satisfy the nonlinear Vogel-Fulcher relation. Well-saturated ferroelectric hysteresis and 50-80% dielectric saturation are observed under high electric field (~1.65 MV cm(-1)). The superlattices demonstrate an 'in-built' field in as grown samples at low probe frequency (<1 kHz), whereas it becomes more symmetric and centered with increase in the probe frequency system (>1 kHz) which rules out the effect of any space charge and interfacial polarization. The P-E loops show around 12.24 J cm(-3) energy density within the experimental limit, but extrapolation of this data suggests that the potential energy density could reach 46 J cm(-3). The current density versus applied electric field indicates an exceptionally high breakdown field (5.8-6.0 MV cm(-1)) and low current density (~10-25 mA cm(-2)) near the breakdown voltage. The current-voltage characteristics reveal that the space charge limited conduction mechanism prevails at very high voltage. PMID:23053172

  3. High energy density capacitors for low cost applications

    NASA Astrophysics Data System (ADS)

    Iyore, Omokhodion David

    Polyvinylidene fluoride (PVDF) and its copolymers with trifluoroethylene, hexafluoropropylene and chlorotrifluoroethylene are the most widely investigated ferroelectric polymers, due to their relatively high electromechanical properties and potential to achieve high energy density. [Bauer, 2010; Zhou et al., 2009] The research community has focused primarily on melt pressed or extruded films of PVDF-based polymers to obtain the highest performance with energy density up to 25 Jcm-3. [Zhou et al., 2009] Solution processing offers an inexpensive, low temperature alternative, which is also easily integrated with flexible electronics. This dissertation focuses on the fabrication of solution-based polyvinylidene fluoride-hexafluoropropylene metal-insulator-metal capacitors on flexible substrates using a photolithographic process. Capacitors were optimized for maximum energy density, high dielectric strength and low leakage current density. It is demonstrated that with the right choice of solvent, electrodes, spin-casting and annealing conditions, high energy density thin film capacitors can be fabricated repeatably and reproducibly. The high electric field dielectric constants were measured and the reliabilities of the polymer capacitors were also evaluated via time-zero breakdown and time-dependent breakdown techniques. Chapter 1 develops the motivation for this work and provides a theoretical overview of dielectric materials, polarization, leakage current and dielectric breakdown. Chapter 2 is a literature review of polymer-based high energy density dielectrics and covers ferroelectric polymers, highlighting PVDF and some of its derivatives. Chapter 3 summarizes some preliminary experimental work and presents materials and electrical characterization that support the rationale for materials selection and process development. Chapter 4 discusses the fabrication of solution-processed PVDF-HFP and modification of its properties by photo-crosslinking. It is followed by a

  4. Dipole polarizability of 120Sn and nuclear energy density functionals

    NASA Astrophysics Data System (ADS)

    Hashimoto, T.; Krumbholz, A. M.; Reinhard, P.-G.; Tamii, A.; von Neumann-Cosel, P.; Adachi, T.; Aoi, N.; Bertulani, C. A.; Fujita, H.; Fujita, Y.; Ganioǧlu, E.; Hatanaka, K.; Ideguchi, E.; Iwamoto, C.; Kawabata, T.; Khai, N. T.; Krugmann, A.; Martin, D.; Matsubara, H.; Miki, K.; Neveling, R.; Okamura, H.; Ong, H. J.; Poltoratska, I.; Ponomarev, V. Yu.; Richter, A.; Sakaguchi, H.; Shimbara, Y.; Shimizu, Y.; Simonis, J.; Smit, F. D.; Süsoy, G.; Suzuki, T.; Thies, J. H.; Yosoi, M.; Zenihiro, J.

    2015-09-01

    The electric dipole strength distribution in 120Sn between 5 and 22 MeV has been determined at the Research Center for Nuclear Physics, Osaka, from polarization transfer observables measured in proton inelastic scattering at E0=295 MeV and forward angles including 0∘. Combined with photoabsorption data, a highly precise electric dipole polarizability αD(120Sn) =8.93 (36 ) fm3 is extracted. The dipole polarizability as isovector observable par excellence carries direct information on nuclear symmetry energy and its density dependence. The correlation of the new value with the well-established αD(208Pb) serves as a test of its prediction by nuclear energy density functionals. Models based on modern Skyrme interactions describe the data fairly well while most calculations based on relativistic Hamiltonians cannot.

  5. Lithium-Based High Energy Density Flow Batteries

    NASA Technical Reports Server (NTRS)

    Bugga, Ratnakumar V. (Inventor); West, William C. (Inventor); Kindler, Andrew (Inventor); Smart, Marshall C. (Inventor)

    2014-01-01

    Systems and methods in accordance with embodiments of the invention implement a lithium-based high energy density flow battery. In one embodiment, a lithium-based high energy density flow battery includes a first anodic conductive solution that includes a lithium polyaromatic hydrocarbon complex dissolved in a solvent, a second cathodic conductive solution that includes a cathodic complex dissolved in a solvent, a solid lithium ion conductor disposed so as to separate the first solution from the second solution, such that the first conductive solution, the second conductive solution, and the solid lithium ionic conductor define a circuit, where when the circuit is closed, lithium from the lithium polyaromatic hydrocarbon complex in the first conductive solution dissociates from the lithium polyaromatic hydrocarbon complex, migrates through the solid lithium ionic conductor, and associates with the cathodic complex of the second conductive solution, and a current is generated.

  6. Error analysis and implementation issues for energy density probe

    NASA Astrophysics Data System (ADS)

    Locey, Lance L.; Woolford, Brady L.; Sommerfeldt, Scott D.; Blotter, Jonathan D.

    2001-05-01

    Previous research has demonstrated the utility of acoustic energy density measurements as a means to gain a greater understanding of acoustic fields. Three spherical energy density probe designs are under development. The first probe design has three orthogonal pairs of surface mounted microphones. The second probe design utilizes a similarly sized sphere with four surface mounted microphones. The four microphones are located at the origin and unit vectors of a Cartesian coordinate system, where the origin and the tips of the three unit vectors all lie on the surface of the sphere. The third probe design consists of a similarly sized sphere, again with four surface microphones, each placed at the vertices of a regular tetrahedron. The sensing elements of all three probes are Panasonic electret microphones. The work presented here will expand on previously reported work, and address bias errors, spherical scattering effects, and practical implementation issues. [Work supported by NASA.

  7. High energy-density science on the National Ignition Facility

    SciTech Connect

    Campbell, E.M.; Cauble, R.; Remington, B.A.

    1997-08-01

    The National Ignition Facility, as well as its French counterpart Le Laser Megajoule, have been designed to confront one of the most difficult and compelling problem in shock physics - the creation of a hot, compassed DT plasma surrounded and confined by cold, nearly degenerate DT fuel. At the same time, these laser facilities will present the shock physics community with unique tools for the study of high energy density matter at states unreachable by any other laboratory technique. Here we describe how these lasers can contribute to investigations of high energy density in the area of material properties and equations of state, extend present laboratory shock techniques such as high-speed jets to new regimes, and allow study of extreme conditions found in astrophysical phenomena.

  8. Present and Future Capabilities of High Energy Density Experiments*

    NASA Astrophysics Data System (ADS)

    Matzen, M. Keith

    2002-04-01

    In recent years, experiments on high energy lasers and pulsed power facilities have successfully reached extreme conditions of temperature and pressure in the laboratory, allowing replication of conditions relevant to areas of high energy density (HED) plasma physics (for example, astrophysics, planetary interiors, stellar physics, and Inertial Confinement Fusion). Experiments in these areas are now routinely providing high quality data in the areas of high energy density hydrodynamics and implosions, radiation transport, and equation-of-state. Current facilities include pulsed-power accelerators, such as the Z facility at Sandia National Laboratories, and high-energy lasers, such as the 60-beam Omega laser at the Laboratory of Laser Energetics at Rochester, as well as other MA-class pulsed-power facilities and kJ-class lasers worldwide. These facilities routinely conduct experiments at radiation temperatures of 200 eV and pressures up to 40 MBar. New facilities, such as the National Ignition Facility (NIF) and the refurbished Z facility, will extend the experimental regimes to higher temperatures and densities. The National Petawatt laser initiative is examining the physics regimes that could be explored by coupling energetic short-pulse lasers (multi-kJ energies at ps pulse widths) to experiments on these large HED facilities. We will review capabilities of the existing HED facilities, highlight examples of recent experimental results in HED plasma physics, discuss new regimes that might be achievable on next-generation facilities (e.g. NIF and refurbished Z), and explore the potential applications resulting from coupling multi-PW laser pulses with HED plasmas produced on these facilities. *Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy under Contract DE-AC04-94AL85000.

  9. Frontiers for Discovery in High Energy Density Physics

    SciTech Connect

    Davidson, R. C.; Katsouleas, T.; Arons, J.; Baring, M.; Deeney, C.; Di Mauro, L.; Ditmire, T.; Falcone, R.; Hammer, D.; Hill, W.; Jacak, B.; Joshi, C.; Lamb, F.; Lee, R.; Logan, B. G.; Melissinos, A.; Meyerhofer, D.; Mori, W.; Murnane, M.; Remington, B.; Rosner, R.; Schneider, D.; Silvera, I.; Stone, J.; Wilde, B.; Zajc. W.

    2004-07-20

    The report is intended to identify the compelling research opportunities of high intellectual value in high energy density physics. The opportunities for discovery include the broad scope of this highly interdisciplinary field that spans a wide range of physics areas including plasma physics, laser and particle beam physics, nuclear physics, astrophysics, atomic and molecular physics, materials science and condensed matter physics, intense radiation-matter interaction physics, fluid dynamics, and magnetohydrodynamics

  10. Radial evolution of the energy density of solar wind fluctuations

    NASA Technical Reports Server (NTRS)

    Zank, G. P.; Matthaeus, W. H.; Smith, C. W.

    1995-01-01

    On the basis of transport theories appropriate to a radially expanding solar wind, we describe new results for the radial evolution of the energy density in solar wind fluctuations at MHD scales. These models include the effects of 'mixing' and driving as well as the possibility of non-isotropic MHD turbulence. Implications of these results for solar wind heating, cosmic ray diffusion and interstellar pick-up ions will also be addressed.

  11. Integrating MODIS and Landsat Data Using the Simplified Surface Energy Balance Approach to Estimate Actual Evapotranspiration at Multiple Scales

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Estimating actual evapotranspiration (ETa) in space and time is critical for developing useful basin water balance models and for monitoring vegetation water use and drought severity analysis. In this study, we combined MODIS and Landsat thermal data using a 'time-limited' stable fractional relation...

  12. Cross-checking the symmetry energy at high densities

    NASA Astrophysics Data System (ADS)

    Yong, Gao-Chan

    2016-04-01

    By considering both the effects of the nucleon-nucleon short-range correlations and the isospin-dependent in-medium inelastic baryon-baryon scattering cross section in the transport model, two unrelated Au + Au experimental measurements at 400 MeV/nucleon beam energy are simultaneously analyzed, and a mildly soft symmetry energy (L (ρ0)=37 MeV) at supra-saturation densities is obtained. This result is compatible with recent result [Phys. Rev. C 92, 064304 (2015), 10.1103/PhysRevC.92.064304] shown by comparing the available data on the electric dipole polarizability with the theoretical predictions.

  13. High Density Thermal Energy Storage with Supercritical Fluids

    NASA Technical Reports Server (NTRS)

    Ganapathi, Gani B.; Wirz, Richard

    2012-01-01

    A novel approach to storing thermal energy with supercritical fluids is being investigated, which if successful, promises to transform the way thermal energy is captured and utilized. The use of supercritical fluids allows cost-affordable high-density storage with a combination of latent heat and sensible heat in the two-phase as well as the supercritical state. This technology will enhance penetration of several thermal power generation applications and high temperature water for commercial use if the overall cost of the technology can be demonstrated to be lower than the current state-of-the-art molten salt using sodium nitrate and potassium nitrate eutectic mixtures.

  14. High Energy Density Physics and Exotic Acceleration Schemes

    SciTech Connect

    Cowan, T.; Colby, E.; /SLAC

    2005-09-27

    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

  15. Highly Compressed Ion Beam for High Energy Density Science

    SciTech Connect

    Friedman, A.; Barnard, J.J.; Briggs, R.J.; Callahan, D.A.; Caporaso, G.J.; Celata, C.M.; Davidson, R.C.; Faltens, A.; Grisham, L.; Grote, D.P.; Henestroza, E.; Kaganovich I.; Lee, E.P.; Lee, R.W.; Leitner, M.; Logan, B.G.; Nelson, S.D.; Olson, C.L.; Penn, G.; Reginato,L.R.; Renk, T.; Rose, D.; Seessler, A.; Staples, J.W.; Tabak, M.; Thoma,C.; Waldron, W.; Welch, D.R.; Wurtele, J.; Yu, S.S.

    2005-05-16

    The Heavy Ion Fusion Virtual National Laboratory is developing the intense ion beams needed to drive matter to the High Energy Density regimes required for Inertial Fusion Energy and other applications. An interim goal is a facility for Warm Dense Matter studies, wherein a target is heated volumetrically without being shocked, so that well-defined states of matter at 1 to 10 eV are generated within a diagnosable region. In the approach they are pursuing, low to medium mass ions with energies just above the Bragg peak are directed onto thin target ''foils,'' which may in fact be foams with mean densities 1% to 10% of solid. This approach complements that being pursued at GSI Darmstadt, wherein high-energy ion beams deposit a small fraction of their energy in a cylindrically target. They present the beam requirements for Warm Dense Matter experiments. The authors discuss neutralized drift compression and final focus experiments and modeling. They describe suitable accelerator architectures based on Drift-Tube Linac, RF, single-gap, Ionization-Front Accelerator, and Pulse-Line Ion Accelerator concepts. The last of these is being pursued experimentally. Finally, they discuss plans toward a user facility for target experiments.

  16. Density functional theory for protein transfer free energy.

    PubMed

    Mills, Eric A; Plotkin, Steven S

    2013-10-24

    We cast the problem of protein transfer free energy within the formalism of density functional theory (DFT), treating the protein as a source of external potential that acts upon the solvent. Solvent excluded volume, solvent-accessible surface area, and temperature dependence of the transfer free energy all emerge naturally within this formalism, and may be compared with simplified "back of the envelope" models, which are also developed here. Depletion contributions to osmolyte induced stability range from 5 to 10 kBT for typical protein lengths. The general DFT transfer theory developed here may be simplified to reproduce a Langmuir isotherm condensation mechanism on the protein surface in the limits of short-ranged interactions, and dilute solute. Extending the equation of state to higher solute densities results in non-monotonic behavior of the free energy driving protein or polymer collapse. Effective interaction potentials between protein backbone or side chains and TMAO are obtained, assuming a simple backbone/side chain two-bead model for the protein with an effective 6-12 potential with the osmolyte. The transfer free energy δg shows significant entropy: d(δg)/dT ≈ 20 kB for a 100-residue protein. The application of DFT to effective solvent forces for use in implicit-solvent molecular dynamics is also developed. The simplest DFT expressions for implicit-solvent forces contain both depletion interactions and an "impeded-solvation" repulsive force at larger distances. PMID:23944753

  17. Dietary Energy Density is Positively Associated with Breast Density among Young Women

    PubMed Central

    Hartman, Terryl J.; Klifa, Catherine J.; Coffman, Donna L.; Mitchell, Diane C.; Vernarelli, Jacqueline A.; Snetselaar, Linda; Horn, Linda Van; Stevens, Victor J.; Robson, Alan; Himes, John; Shepherd, John; Dorgan, Joanne F.

    2014-01-01

    Background Breast density is an established predictor of breast cancer risk, and there is considerable interest in associations of modifiable lifestyle factors, such as diet, with breast density. Objective To determine if dietary energy density (ED) is associated with percent dense breast volume (%DBV) and absolute dense breast volume (ADBV) in young women. Design A cross-sectional analysis was conducted with women who participated in the Dietary Intervention Study in Children Follow-Up Study (DISC06). %DBV and ADBV were measured by magnetic resonance imaging (MRI). Diet was assessed by three 24-hour recalls. Dietary ED (kcal/g) was calculated using three methods: (1) food only, (2) food and caloric beverages, and (3) food and all beverages. Participants/setting 172 women (25–29 years) who were enrolled in the DISC06 study. Subjects who reported breast augmentation or reduction surgery or were pregnant or lactating within three months before breast density assessment were excluded. Main outcome measures ADBV and %DBV. Statistical analyses performed Multivariable linear mixed effects models were used. Final models were adjusted for race, smoking status, education, parity, duration of sex hormone use, whole body percent fat, childhood BMI z-score, and energy from beverages. Results After adjustment, each 1 kcal/g unit increase in food-only ED was associated with a 25.9% (95% confidence interval = 6.2 to 56.8%) increase in %DBV (p=0.01). Childhood BMI z-score modified the association between food-only ED and %DBV such that a significant positive association was observed only in women who were heavier as children. Food-only ED was not associated with ADBV in all women, but a borderline significant positive association was observed in women who had higher childhood BMI z-scores. Conclusions This is the first report to suggest a potential role for dietary ED in breast density; the effects of long-term exposure to high ED diets on breast cancer risk remain unknown. PMID

  18. Density Functional Theory in High Energy Density Physics: phase-diagram and electrical conductivity of water

    NASA Astrophysics Data System (ADS)

    Mattsson, Thomas R.

    2007-06-01

    Atomistic simulations employing Density Functional Theory (DFT) have recently emerged as a powerful way of increasing our understanding of materials and processes in high energy density physics. Knowledge of the properties of water (equation of state, electrical conductivity, diffusion, low-energy opacity) is essential for correctly describing the physics of giant planets as well as shock waves in water. Although a qualitative picture of water electrical conductivity has emerged, the necessary quantitative information is scarce over a wide range of temperature and density. Since experiments can only access certain areas of phase space, and often require modeling as a part of the analysis, Quantum Molecular Dynamics simulations play a vital role. Using finite-temperature density functional theory (FT-DFT), we have investigated the structure and electronic conductivity of water across three phase transitions (molecular liquid/ ionic liquid/ superionic/ electronic liquid). The ionic contribution to the conduction is calculated from proton diffusion and the electronic contribution is calculated using the Kubo-Greenwood formula. The calculations are performed with VASP, a plane-wave pseudo-potential code. There is a rapid transition to ionic conduction at 2000 K and 2 g/cm^3, whereas electronic conduction dominates at temperatures at and above 6000 K&[tilde;1]. Contrary to earlier results using the Car-Parrinello method&[tilde;2], we predict that the fluid bordering the superionic phase is conducting above 4000 K and 100 GPa. Our comprehensive use of FT-DFT explains the new findings. The calculated conductivity is compared to experimental data. I gratefully acknowledge Mike Desjarlais, my collaborator in this effort. The LDRD office at Sandia supported this work. Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL

  19. Towards the island of stability with relativistic energy density functionals

    SciTech Connect

    Prassa, V.; Niksic, T.; Lalazissis, G. A.; Vretenar, D.

    2012-10-20

    Relativistic energy density functionals (REDF) provide a complete and accurate, global description of nuclear structure phenomena. Modern semi-empirical functionals, adjusted to the nuclear matter equation of state and to empirical masses of deformed nuclei, are applied to studies of shapes of superheavy nuclei. The theoretical framework is tested in a comparison to empirical masses, quadrupole deformations, and energy barriers of actinide nuclei. The model is used in a self-consistent mean-field calculation of spherical, axial and triaxial shapes of superheavy nuclei, alpha-decay energies and lifetimes. The effect of explicit treatment of collective correlations is analyzed in calculations that consistently use a collective Hamiltonian model based on REDFs.

  20. New potential high energy density compounds: Oxadiaziridine derivatives

    NASA Astrophysics Data System (ADS)

    Yang, Jing; Chi, Wei-Jie

    2014-10-01

    The -CN, -N3, -NF2, -NH2, -NHNO2, -NO2, and -ONO2 derivatives of oxadiaziridine were studied using B3LYP/6-311G** level of density functional theory. The gas phase heats of formation of oxadiaziridine derivatives were calculated by isodesmic reaction. All these compounds have high and positive heats of formation due to strain energies of small ring. Detonation properties were calculated via Kamlet-Jacobes equations and specific impulse. The effects of substituent groups on detonation performance were discussed. The impact sensitivity was estimated according to the "available free space per molecule in unit cell" and "energy gaps" methods. The similar conclusions were given by two different methods. The effects of substituents on impact sensitivity were discussed. According to the given estimations of detonation performance and sensitivity, some oxadiaziridine derivatives may be considered promising high energies materials.

  1. Energy boost in laser wakefield accelerators using sharp density transitions

    NASA Astrophysics Data System (ADS)

    Döpp, A.; Guillaume, E.; Thaury, C.; Lifschitz, A.; Ta Phuoc, K.; Malka, V.

    2016-05-01

    The energy gain in laser wakefield accelerators is limited by dephasing between the driving laser pulse and the highly relativistic electrons in its wake. Since this phase depends on both the driver and the cavity length, the effects of dephasing can be mitigated with appropriate tailoring of the plasma density along propagation. Preceding studies have discussed the prospects of continuous phase-locking in the linear wakefield regime. However, most experiments are performed in the highly non-linear regime and rely on self-guiding of the laser pulse. Due to the complexity of the driver evolution in this regime, it is much more difficult to achieve phase locking. As an alternative, we study the scenario of rapid rephasing in sharp density transitions, as was recently demonstrated experimentally. Starting from a phenomenological model, we deduce expressions for the electron energy gain in such density profiles. The results are in accordance with particle-in-cell simulations, and we present gain estimations for single and multiple stages of rephasing.

  2. Density dependence of the nuclear symmetry energy: A microscopic perspective

    SciTech Connect

    Vidana, Isaac; Providencia, Constanca; Polls, Artur; Rios, Arnau

    2009-10-15

    We perform a systematic analysis of the density dependence of nuclear symmetry energy within the microscopic Brueckner-Hartree-Fock (BHF) approach using the realistic Argonne V18 nucleon-nucleon potential plus a phenomenological three-body force of Urbana type. Our results are compared thoroughly with those arising from several Skyrme and relativistic effective models. The values of the parameters characterizing the BHF equation of state of isospin asymmetric nuclear matter fall within the trends predicted by those models and are compatible with recent constraints coming from heavy ion collisions, giant monopole resonances, or isobaric analog states. In particular we find a value of the slope parameter L=66.5 MeV, compatible with recent experimental constraints from isospin diffusion, L=88{+-}25 MeV. The correlation between the neutron skin thickness of neutron-rich isotopes and the slope L and curvature K{sub sym} parameters of the symmetry energy is studied. Our BHF results are in very good agreement with the correlations already predicted by other authors using nonrelativistic and relativistic effective models. The correlations of these two parameters and the neutron skin thickness with the transition density from nonuniform to {beta}-stable matter in neutron stars are also analyzed. Our results confirm that there is an inverse correlation between the neutron skin thickness and the transition density.

  3. Rationally designed polyimides for high-energy density capacitor applications.

    PubMed

    Ma, Rui; Baldwin, Aaron F; Wang, Chenchen; Offenbach, Ido; Cakmak, Mukerrem; Ramprasad, Rampi; Sotzing, Gregory A

    2014-07-01

    Development of new dielectric materials is of great importance for a wide range of applications for modern electronics and electrical power systems. The state-of-the-art polymer dielectric is a biaxially oriented polypropylene (BOPP) film having a maximal energy density of 5 J/cm(3) and a high breakdown field of 700 MV/m, but with a limited dielectric constant (∼2.2) and a reduced breakdown strength above 85 °C. Great effort has been put into exploring other materials to fulfill the demand of continuous miniaturization and improved functionality. In this work, a series of polyimides were investigated as potential polymer materials for this application. Polyimide with high dielectric constants of up to 7.8 that exhibits low dissipation factors (<1%) and high energy density around 15 J/cm(3), which is 3 times that of BOPP, was prepared. Our syntheses were guided by high-throughput density functional theory calculations for rational design in terms of a high dielectric constant and band gap. Correlations of experimental and theoretical results through judicious variations of polyimide structures allowed for a clear demonstration of the relationship between chemical functionalities and dielectric properties. PMID:24911181

  4. Electromagnetic potentials basis for energy density and power flux

    NASA Astrophysics Data System (ADS)

    Puthoff, H. E.

    2016-09-01

    In rounding out the education of students in advanced courses in applied electromagnetics it is incumbent on us as mentors to raise issues that encourage appreciation of certain subtle aspects that are often overlooked during first exposure to the field. One of these has to do with the interplay between fields and potentials, with the latter often seen as just a convenient mathematical artifice useful in solving Maxwell’s equations. Nonetheless, to those practiced in application it is well understood that various alternatives in the use of fields and potentials are available within electromagnetic (EM) theory for the definitions of energy density, momentum transfer, EM stress–energy tensor, and so forth. Although the various options are all compatible with the basic equations of electrodynamics (e.g., Maxwell’s equations, Lorentz force law, gauge invariance), nonetheless certain alternative formulations lend themselves to being seen as preferable to others with regard to the transparency of their application to physical problems of interest. Here we argue for the transparency of an energy density/power flux option based on the EM potentials alone.

  5. High-energy density physics at Los Alamos

    NASA Astrophysics Data System (ADS)

    Byrnes, P.

    1993-03-01

    This brochure describes the facilities of the Above Ground Experiments 2 (AGEX 2) and the Inertial Confinement Fusion (ICF) programs at Los Alamo. Combined, these programs represent, an unparalleled capability to address important issues in high-energy density physics that are critical to the future defense, energy, and research needs of the United States. The mission of the AGEX 2 program at Los Alamos is to provide additional experimental opportunities for the nuclear weapons program. For this purpose we have assembled at Los Alamos the broadest array of high-energy density physics facilities of any laboratory in the world. Inertial confinement fusion seeks to achieve thermonuclear burn on a laboratory scale through the implosion of a small quantity of deuterium and tritium fuel to very high pressure and temperature. The Los Alamos ICF program is focused on target physics. With the largest scientific computing center in the world, We can perform calculations of unprecedented sophistication and precision. We field experiments at facilities worldwide--including our own Trident and Mercury lasers--to confirm our understanding and to provide the necessary data base to proceed toward the historic goal of controlled fusion in the laboratory. The ultrahigh magnetic fields produced in our high explosive pulsed-power generators can be used in a wide variety of solid state physics and temperature superconductor studies. The structure and dynamics of planetary atmospheres can be simulated through the compression of gas mixtures.

  6. Adiabatic corrections to density functional theory energies and wave functions.

    PubMed

    Mohallem, José R; Coura, Thiago de O; Diniz, Leonardo G; de Castro, Gustavo; Assafrão, Denise; Heine, Thomas

    2008-09-25

    The adiabatic finite-nuclear-mass-correction (FNMC) to the electronic energies and wave functions of atoms and molecules is formulated for density-functional theory and implemented in the deMon code. The approach is tested for a series of local and gradient corrected density functionals, using MP2 results and diagonal-Born-Oppenheimer corrections from the literature for comparison. In the evaluation of absolute energy corrections of nonorganic molecules the LDA PZ81 functional works surprisingly better than the others. For organic molecules the GGA BLYP functional has the best performance. FNMC with GGA functionals, mainly BLYP, show a good performance in the evaluation of relative corrections, except for nonorganic molecules containing H atoms. The PW86 functional stands out with the best evaluation of the barrier of linearity of H2O and the isotopic dipole moment of HDO. In general, DFT functionals display an accuracy superior than the common belief and because the corrections are based on a change of the electronic kinetic energy they are here ranked in a new appropriate way. The approach is applied to obtain the adiabatic correction for full atomization of alcanes C(n)H(2n+2), n = 4-10. The barrier of 1 mHartree is approached for adiabatic corrections, justifying its insertion into DFT. PMID:18537228

  7. High energy density Z-pinch plasmas using flow stabilization

    SciTech Connect

    Shumlak, U. Golingo, R. P. Nelson, B. A. Bowers, C. A. Doty, S. A. Forbes, E. G. Hughes, M. C. Kim, B. Knecht, S. D. Lambert, K. K. Lowrie, W. Ross, M. P. Weed, J. R.

    2014-12-15

    The ZaP Flow Z-Pinch research project[1] at the University of Washington investigates the effect of sheared flows on MHD instabilities. Axially flowing Z-pinch plasmas are produced that are 100 cm long with a 1 cm radius. The plasma remains quiescent for many radial Alfvén times and axial flow times. The quiescent periods are characterized by low magnetic mode activity measured at several locations along the plasma column and by stationary visible plasma emission. Plasma evolution is modeled with high-resolution simulation codes – Mach2, WARPX, NIMROD, and HiFi. Plasma flow profiles are experimentally measured with a multi-chord ion Doppler spectrometer. A sheared flow profile is observed to be coincident with the quiescent period, and is consistent with classical plasma viscosity. Equilibrium is determined by diagnostic measurements: interferometry for density; spectroscopy for ion temperature, plasma flow, and density[2]; Thomson scattering for electron temperature; Zeeman splitting for internal magnetic field measurements[3]; and fast framing photography for global structure. Wall stabilization has been investigated computationally and experimentally by removing 70% of the surrounding conducting wall to demonstrate no change in stability behavior.[4] Experimental evidence suggests that the plasma lifetime is only limited by plasma supply and current waveform. The flow Z-pinch concept provides an approach to achieve high energy density plasmas,[5] which are large, easy to diagnose, and persist for extended durations. A new experiment, ZaP-HD, has been built to investigate this approach by separating the flow Z-pinch formation from the radial compression using a triaxial-electrode configuration. This innovation allows more detailed investigations of the sheared flow stabilizing effect, and it allows compression to much higher densities than previously achieved on ZaP by reducing the linear density and increasing the pinch current. Experimental results and

  8. High energy density Z-pinch plasmas using flow stabilization

    NASA Astrophysics Data System (ADS)

    Shumlak, U.; Golingo, R. P.; Nelson, B. A.; Bowers, C. A.; Doty, S. A.; Forbes, E. G.; Hughes, M. C.; Kim, B.; Knecht, S. D.; Lambert, K. K.; Lowrie, W.; Ross, M. P.; Weed, J. R.

    2014-12-01

    The ZaP Flow Z-Pinch research project[1] at the University of Washington investigates the effect of sheared flows on MHD instabilities. Axially flowing Z-pinch plasmas are produced that are 100 cm long with a 1 cm radius. The plasma remains quiescent for many radial Alfvén times and axial flow times. The quiescent periods are characterized by low magnetic mode activity measured at several locations along the plasma column and by stationary visible plasma emission. Plasma evolution is modeled with high-resolution simulation codes - Mach2, WARPX, NIMROD, and HiFi. Plasma flow profiles are experimentally measured with a multi-chord ion Doppler spectrometer. A sheared flow profile is observed to be coincident with the quiescent period, and is consistent with classical plasma viscosity. Equilibrium is determined by diagnostic measurements: interferometry for density; spectroscopy for ion temperature, plasma flow, and density[2]; Thomson scattering for electron temperature; Zeeman splitting for internal magnetic field measurements[3]; and fast framing photography for global structure. Wall stabilization has been investigated computationally and experimentally by removing 70% of the surrounding conducting wall to demonstrate no change in stability behavior.[4] Experimental evidence suggests that the plasma lifetime is only limited by plasma supply and current waveform. The flow Z-pinch concept provides an approach to achieve high energy density plasmas,[5] which are large, easy to diagnose, and persist for extended durations. A new experiment, ZaP-HD, has been built to investigate this approach by separating the flow Z-pinch formation from the radial compression using a triaxial-electrode configuration. This innovation allows more detailed investigations of the sheared flow stabilizing effect, and it allows compression to much higher densities than previously achieved on ZaP by reducing the linear density and increasing the pinch current. Experimental results and scaling

  9. Density-based Energy Decomposition Analysis for Intermolecular Interactions with Variationally Determined Intermediate State Energies

    SciTech Connect

    Wu, Q.; Ayers, P.W.; Zhang, Y.

    2009-10-28

    The first purely density-based energy decomposition analysis (EDA) for intermolecular binding is developed within the density functional theory. The most important feature of this scheme is to variationally determine the frozen density energy, based on a constrained search formalism and implemented with the Wu-Yang algorithm [Q. Wu and W. Yang, J. Chem. Phys. 118, 2498 (2003) ]. This variational process dispenses with the Heitler-London antisymmetrization of wave functions used in most previous methods and calculates the electrostatic and Pauli repulsion energies together without any distortion of the frozen density, an important fact that enables a clean separation of these two terms from the relaxation (i.e., polarization and charge transfer) terms. The new EDA also employs the constrained density functional theory approach [Q. Wu and T. Van Voorhis, Phys. Rev. A 72, 24502 (2005)] to separate out charge transfer effects. Because the charge transfer energy is based on the density flow in real space, it has a small basis set dependence. Applications of this decomposition to hydrogen bonding in the water dimer and the formamide dimer show that the frozen density energy dominates the binding in these systems, consistent with the noncovalent nature of the interactions. A more detailed examination reveals how the interplay of electrostatics and the Pauli repulsion determines the distance and angular dependence of these hydrogen bonds.

  10. Average transverse momentum and energy density in high-energy nucleus-nucleus collisions

    NASA Technical Reports Server (NTRS)

    Burnett, T. H.; Dake, S.; Fuki, M.; Gregory, J. C.; Hayashi, T.; Holynski, R.; Iwai, J.; Jones, W. V.; Jurak, A.; Lord, J. J.

    1986-01-01

    Emulsion chambers were used to measure the transverse momenta of photons or pi(0) mesons produced in high-energy cosmic-ray nucleus-nucleus collisions. A group of events having large average transverse momenta has been found which apparently exceeds the expected limiting values. Analysis of the events at early interaction times, of the order of 1 fm/c, indicates that the observed transverse momentum increases with both rapidity density and energy density.

  11. High energy density capacitors using nano-structure multilayer technology

    SciTech Connect

    Barbee, T.W. Jr.; Johnson, G.W.; O`Brien, D.W.

    1992-08-01

    Today, many pulse power and industrial applications are limited by capacitor performance. While incremental improvements are anticipated from existing capacitor technologies, significant advances are needed in energy density to enable these applications for both the military and for American economic competitiveness. We propose a program to research and develop a novel technology for making high voltage, high energy density capacitors. Nano-structure multilayer technologies developed at LLNL may well provide a breakthrough in capacitor performance. Our controlled sputtering techniques are capable of laying down extraordinarily smooth sub-micron layers of dielectric and conductor materials. With this technology, high voltage capacitors with an order of magnitude improvement in energy density may be achievable. Well-understood dielectrics and new materials will be investigated for use with this technology. Capacitors developed by nano-structure multilayer technology are inherently solid state, exhibiting extraordinary mechanical and thermal properties. The conceptual design of a Notepad capacitor is discussed to illustrate capacitor and capacitor bank design and performance with this technology. We propose a two phase R&D program to address DNA`s capacitor needs for electro-thermal propulsion and similar pulse power programs. Phase 1 will prove the concept and further our understanding of dielectric materials and design tradeoffs with multilayers. Nano-structure multilayer capacitors will be developed and characterized. As our materials research and modeling prove successful, technology insertion in our capacitor designs will improve the possibility for dramatic performance improvements. In Phase 2, we will make Notepad capacitors, construct a capacitor bank and demonstrate its performance in a meaningful pulse power application. We will work with industrial partners to design full scale manufacturing and move this technology to industry for volume production.

  12. Finiteness of the vacuum energy density in quantum electrodynamics

    NASA Astrophysics Data System (ADS)

    Manoukian, Edward B.

    1983-03-01

    Recent interest in the finiteness problem of the vacuum energy density (VED) in finite QED has motivated us to reexamine this problem in the light of an analysis we have carried out earlier. By a loopwise summation procedure, supplemented by a renormalization-group analysis, we study the finiteness of the VED with α, the renormalized fine-structure constant, fixed in the process as the (infinite order) zero of the eigenvalue condition F[1](x)|x=α=0∞, and with the electron mass totally dynamical of origin. We propose a possible finite solution for the VED in QED which may require only one additional eigenvalue condition for α.

  13. Nuclear clustering in the energy density functional approach

    SciTech Connect

    Ebran, J.-P.; Khan, E.; Nikšić, T.; Vretenar, D.

    2015-10-15

    Nuclear Energy Density Functionals (EDFs) are a microscopic tool of choice extensively used over the whole chart to successfully describe the properties of atomic nuclei ensuing from their quantum liquid nature. In the last decade, they also have proved their ability to deal with the cluster phenomenon, shedding a new light on its fundamental understanding by treating on an equal footing both quantum liquid and cluster aspects of nuclei. Such a unified microscopic description based on nucleonic degrees of freedom enables to tackle the question pertaining to the origin of the cluster phenomenon and emphasizes intrinsic mechanisms leading to the emergence of clusters in nuclei.

  14. Ab initio derivation of model energy density functionals

    NASA Astrophysics Data System (ADS)

    Dobaczewski, Jacek

    2016-08-01

    I propose a simple and manageable method that allows for deriving coupling constants of model energy density functionals (EDFs) directly from ab initio calculations performed for finite fermion systems. A proof-of-principle application allows for linking properties of finite nuclei, determined by using the nuclear nonlocal Gogny functional, to the coupling constants of the quasilocal Skyrme functional. The method does not rely on properties of infinite fermion systems but on the ab initio calculations in finite systems. It also allows for quantifying merits of different model EDFs in describing the ab initio results.

  15. Nuclear clustering in the energy density functional approach

    NASA Astrophysics Data System (ADS)

    Ebran, J.-P.; Khan, E.; Nikšić, T.; Vretenar, D.

    2015-10-01

    Nuclear Energy Density Functionals (EDFs) are a microscopic tool of choice extensively used over the whole chart to successfully describe the properties of atomic nuclei ensuing from their quantum liquid nature. In the last decade, they also have proved their ability to deal with the cluster phenomenon, shedding a new light on its fundamental understanding by treating on an equal footing both quantum liquid and cluster aspects of nuclei. Such a unified microscopic description based on nucleonic degrees of freedom enables to tackle the question pertaining to the origin of the cluster phenomenon and emphasizes intrinsic mechanisms leading to the emergence of clusters in nuclei.

  16. Relativistic Energy Density Functionals: Exotic modes of excitation

    SciTech Connect

    Vretenar, D.; Paar, N.; Marketin, T.

    2008-11-11

    The framework of relativistic energy density functionals has been applied to the description of a variety of nuclear structure phenomena, not only in spherical and deformed nuclei along the valley of {beta}-stability, but also in exotic systems with extreme isospin values and close to the particle drip-lines. Dynamical aspects of exotic nuclear structure have been investigated with the relativistic quasiparticle random-phase approximation. We present results for the evolution of low-lying dipole (pygmy) strength in neutron-rich nuclei, and charged-current neutrino-nucleus cross sections.

  17. Alternative definitions of the frozen energy in energy decomposition analysis of density functional theory calculations.

    PubMed

    Horn, Paul R; Head-Gordon, Martin

    2016-02-28

    In energy decomposition analysis (EDA) of intermolecular interactions calculated via density functional theory, the initial supersystem wavefunction defines the so-called "frozen energy" including contributions such as permanent electrostatics, steric repulsions, and dispersion. This work explores the consequences of the choices that must be made to define the frozen energy. The critical choice is whether the energy should be minimized subject to the constraint of fixed density. Numerical results for Ne2, (H2O)2, BH3-NH3, and ethane dissociation show that there can be a large energy lowering associated with constant density orbital relaxation. By far the most important contribution is constant density inter-fragment relaxation, corresponding to charge transfer (CT). This is unwanted in an EDA that attempts to separate CT effects, but it may be useful in other contexts such as force field development. An algorithm is presented for minimizing single determinant energies at constant density both with and without CT by employing a penalty function that approximately enforces the density constraint. PMID:26931692

  18. Alternative definitions of the frozen energy in energy decomposition analysis of density functional theory calculations

    NASA Astrophysics Data System (ADS)

    Horn, Paul R.; Head-Gordon, Martin

    2016-02-01

    In energy decomposition analysis (EDA) of intermolecular interactions calculated via density functional theory, the initial supersystem wavefunction defines the so-called "frozen energy" including contributions such as permanent electrostatics, steric repulsions, and dispersion. This work explores the consequences of the choices that must be made to define the frozen energy. The critical choice is whether the energy should be minimized subject to the constraint of fixed density. Numerical results for Ne2, (H2O)2, BH3-NH3, and ethane dissociation show that there can be a large energy lowering associated with constant density orbital relaxation. By far the most important contribution is constant density inter-fragment relaxation, corresponding to charge transfer (CT). This is unwanted in an EDA that attempts to separate CT effects, but it may be useful in other contexts such as force field development. An algorithm is presented for minimizing single determinant energies at constant density both with and without CT by employing a penalty function that approximately enforces the density constraint.

  19. Equatorial electron energy and number densities in the Jovian magnetosphere

    NASA Technical Reports Server (NTRS)

    Luthey, J. L.

    1972-01-01

    A synchrotron model with a Maxwellian energy distribution of the form e to the (-E/E sub 0) power is used in a comparison with spatially resolved radio interferometric measurements of the Jovian emission. The observations of the decimeter radiation as a function of equatorial distance at 10.4 and 21 cm wavelength were reduced to source emission/cc of source electrons in each of 16 concentric rings. The peak energies for isotropically distributed electrons exceeded the maximum energy for flat orbiting electrons, and the peaks were generally located from 2.25 to 3 Jupiter radii. Beyond 3 radii, the order of magnitude on number density became a sensitive function of pitch angle distribution. The total equatorial intensities at 75 cm wavelength were computed for (E sub 0)(r) and n(r) at different values of B sub 0. The radiative half life for electrons of initial energy E sub 0 in a dipole field was calculated and found to be nearly constant at one year or less for altitudes at and below the position in peak energy.

  20. Evolution of the energy density in the static universe

    NASA Astrophysics Data System (ADS)

    Khokhlov, D. L.

    2011-10-01

    The Einstein static model of the universe as a whole is considered. The Hubble law is explained by the Doppler effect due to the downward inertial acceleration along a certain radius experienced by an observer in the center of the universe, with the total acceleration over all radii being equal zero. Evolution of the universe is introduced through the wave function of the universe dependent on time. This yields the energy density of the universe hence the temperature of the universe dependent on time. On the contrary, the energy, forth and intensity of radiation are fixed with time that allows to develop the Newtonian physics in the whole universe. The time-temperature relation of the universe in the model considered is the same as in the radiation dominated universe in the Friedmann model that allows to explain primordial nucleosynthesis as it is in the standard scenario. The modern parameters of the universe in the model considered are consistent with the observations.

  1. Causes of irregular energy density in f (R ,T ) gravity

    NASA Astrophysics Data System (ADS)

    Yousaf, Z.; Bamba, Kazuharu; Bhatti, M. Zaeem-ul-Haq

    2016-06-01

    We investigate irregularity factors for a self-gravitating spherical star evolving in the presence of an imperfect fluid. We explore the gravitational field equations and the dynamical equations with the systematic construction in f (R ,T ) gravity, where T is the trace of the energy-momentum tensor. Furthermore, we analyze two well-known differential equations (which occupy principal importance in the exploration of causes of energy density inhomogeneities) with the help of the Weyl tensor and the conservation laws. The irregularity factors for a spherical star are examined for particular cases of dust and isotropic and anisotropic fluids in dissipative and nondissipative regimes in the framework of f (R ,T ) gravity. It is found that, as the complexity of the matter with the anisotropic stresses increases, the inhomogeneity factor corresponds more closely to one of the structure scalars.

  2. Descriptions of carbon isotopes within the energy density functional theory

    SciTech Connect

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

    2014-10-24

    Within the energy density functional (EDF) theory, the structure properties of Carbon isotopes are systematically studied. The shell model calculations are done for both even-A and odd-A nuclei, to study the structure of rich-neutron Carbon isotopes. The EDF theory indicates the single-neutron halo structures in {sup 15}C, {sup 17}C and {sup 19}C, and the two-neutron halo structures in {sup 16}C and {sup 22}C nuclei. It is also found that close to the neutron drip-line, there exist amazing increase in the neutron radii and decrease on the binding energies BE, which are tightly related with the blocking effect and correspondingly the blocking effect plays a significant role in the shell model configurations.

  3. Curvature and Frontier Orbital Energies in Density Functional Theory

    SciTech Connect

    Stein, Tamar; Autschbach, Jochen; Govind, Niranjan; Kronik, Leeor; Baer, Roi

    2012-12-20

    Perdew et al. [Phys. Rev. Lett 49, 1691 (1982)] discovered and proved two different properties that exact Kohn-Sham density functional theory (DFT) must obey: (i) The exact total energy versus particle number must be a series of linear segments between integer electron points; (ii) Across an integer number of electrons, the exchange-correlation potential may ``jump’’ by a constant, known as the derivative discontinuity (DD). Here, we show analytically that in both the original and the generalized Kohn-Sham formulation of DFT, the two are in fact two sides of the same coin. Absence of a derivative discontinuity necessitates deviation from piecewise linearity, and the latter can be used to correct for the former, thereby restoring the physical meaning of the orbital energies. Using selected small molecules, we show that this results in a simple correction scheme for any underlying functional, including semi-local and hybrid functionals as well as Hartree-Fock theory, suggesting a practical correction for the infamous gap problem of density functional theory. Moreover, we show that optimally-tuned range-separated hybrid functionals can inherently minimize both DD and curvature, thus requiring no correction, and show that this can be used as a sound theoretical basis for novel tuning strategies.

  4. Characterizing high-energy-density propellants for space propulsion applications

    NASA Astrophysics Data System (ADS)

    Kokan, Timothy S.; Olds, John R.; Seitzman, Jerry M.; Ludovice, Peter J.

    2009-10-01

    A technique for computationally determining the thermophysical properties of high-energy-density matter (HEDM) propellants is presented. HEDM compounds are of interest in the liquid rocket engine industry due to their high density and high energy content relative to existing industry-standard propellants. In order to accurately model rocket engine performance, cost and weight in a conceptual design environment, several thermodynamic and physical properties are required over a range of temperatures and pressures. The approach presented here combines quantum mechanical and molecular dynamic (MD) calculations and group additivity methods. A method for improving the force field model coefficients used in the MD is included. This approach is used to determine thermophysical properties for two HEDM compounds of interest: quadricyclane and 2-azido-N,N-dimethylethanamine (DMAZ). The modified force field approach provides results that more accurately match experimental data than the unmodified approach. Launch vehicle and Lunar lander case studies are presented to quantify the system level impact of employing quadricyclane and DMAZ rather than industry standard propellants. In both cases, the use of HEDM propellants provides reductions in vehicle mass compared to industry standard propellants. The results demonstrate that HEDM propellants can be an attractive technology for future launch vehicle and Lunar lander applications.

  5. Vacuum energy density and pressure near a soft wall

    NASA Astrophysics Data System (ADS)

    Murray, S. W.; Whisler, C. M.; Fulling, S. A.; Wagner, Jef; Carter, H. B.; Lujan, David; Mera, F. D.; Settlemyre, T. E.

    2016-05-01

    Perfectly conducting boundaries, and their Dirichlet counterparts for quantum scalar fields, predict nonintegrable energy densities. A more realistic model with a finite ultraviolet cutoff yields two inconsistent values for the force on a curved or edged boundary (the "pressure anomaly"). A still more realistic, but still easily calculable, model replaces the hard wall by a power-law potential; because it involves no a posteriori modification of the formulas calculated from the theory, this model should be anomaly free. Here we first set up the formalism and notation for the quantization of a scalar field in the background of a planar soft wall, and we approximate the reduced Green function in perturbative and WKB limits (the latter being appropriate when either the mode frequency or the depth into the wall is sufficiently large). Then we display numerical calculations of the energy density and pressure for the region outside the wall, which show that the pressure anomaly does not occur there. Calculations inside the wall are postponed to later papers, which must tackle the regularization and renormalization of divergences induced by the potential in the bulk region.

  6. Strongly Interacting Matter at Very High Energy Density

    SciTech Connect

    McLerran, L.

    2011-06-05

    The authors discuss the study of matter at very high energy density. In particular: what are the scientific questions; what are the opportunities to makes significant progress in the study of such matter and what facilities are now or might be available in the future to answer the scientific questions? The theoretical and experimental study of new forms of high energy density matter is still very much a 'wild west' field. There is much freedom for developing new concepts which can have order one effects on the way we think about such matter. It is also a largely 'lawless' field, in that concepts and methods are being developed as new information is generated. There is also great possibility for new experimental discovery. Most of the exciting results from RHIC experiments were unanticipated. The methods used for studying various effects like flow, jet quenching, the ridge, two particle correlations etc. were developed as experiments evolved. I believe this will continue to be the case at LHC and as we use existing and proposed accelerators to turn theoretical conjecture into tangible reality. At some point this will no doubt evolve into a precision science, and that will make the field more respectable, but for my taste, the 'wild west' times are the most fun.

  7. Vacuum energy density and pressure of a massive scalar field

    NASA Astrophysics Data System (ADS)

    Mera, Fernando Daniel; Fulling, S. A.

    2015-06-01

    With a view toward application of the Pauli-Villars regularization method to the Casimir energy of boundaries, we calculate the expectation values of the components of the stress tensor of a confined massive field in 1+1 space-time dimensions. Previous papers by Hays and Fulling are bridged and generalized. The Green function for the time-independent Schrödinger equation is constructed from the Green function for the whole line by the method of images; equivalently, the one-dimensional system is solved exactly in terms of closed classical paths and periodic orbits. Terms in the energy density and in the eigenvalue density attributable to the two boundaries individually and those attributable to the confinement of the field to a finite interval are distinguished so that their physical origins are clear. Then the pressure is found similarly from the cylinder kernel, the Green function associated most directly with an exponential frequency cutoff of the Fourier mode expansion. Finally, we discuss how the theory could be rendered finite by the Pauli-Villars method.

  8. Creating High Energy Density Jets in Laboratory Environments

    NASA Astrophysics Data System (ADS)

    Coker, Robert

    2005-04-01

    A new experimental platform for the investigation of high Mach-number, high energy-density jets has been developed at the University of Rochester's Omega laser facility. Assuming the scalability of the Euler equations, the resulting mm-sized jets should scale to astrophysical objects such as Herbig-Haro objects and jet-driven supernovae that may involve jets with similar internal Mach numbers. This scalability still holds in the presence of radiation as long as the relative importance of radiative cooling is similar. In these experiments, either direct or indirect laser drive is used to launch a strong shock into a 125 micron thick titanium foil target that caps a 700 micron thick titanium washer. After the shock breaks out into the 300 micron diameter cylindrical hole in the washer, a dense, well-collimated jet with an energy density of more than 0.1 MJ per cc is formed. The jet is then imaged as it propagates for 100s of ns down a cylinder of low-density polymer foam. The experiments are diagnosed by point-projection with a micro-dot vanadium backligher. The field of view is several mm and the resolution is 15 microns. The X-ray radiographs show the hydrodynamically unstable jet and the bow shock driving into the surrounding foam. Such complex experimental data provide a challenge to hydrocodes and so are being used to test the hydrodynamic simulations of these types of flows. Initial comparisons between the data and LANL and AWE simulations will be shown. However, the high Reynolds numbers of both the laboratory and astrophysical jets suggest that, given sufficient time and shear, turbulence should develop; this cannot be reliably modeled by present, resolution-limited simulations. Future work concerning the applicability of the Omega experiments to astrophysical objects and the quantitative study of turbulent mixing via subgrid-scale models will be discussed.

  9. Energy density matrix formalism for interacting quantum systems: a quantum Monte Carlo study

    SciTech Connect

    Krogel, Jaron T; Kim, Jeongnim; Reboredo, Fernando A

    2014-01-01

    We develop an energy density matrix that parallels the one-body reduced density matrix (1RDM) for many-body quantum systems. Just as the density matrix gives access to the number density and occupation numbers, the energy density matrix yields the energy density and orbital occupation energies. The eigenvectors of the matrix provide a natural orbital partitioning of the energy density while the eigenvalues comprise a single particle energy spectrum obeying a total energy sum rule. For mean-field systems the energy density matrix recovers the exact spectrum. When correlation becomes important, the occupation energies resemble quasiparticle energies in some respects. We explore the occupation energy spectrum for the finite 3D homogeneous electron gas in the metallic regime and an isolated oxygen atom with ground state quantum Monte Carlo techniques imple- mented in the QMCPACK simulation code. The occupation energy spectrum for the homogeneous electron gas can be described by an effective mass below the Fermi level. Above the Fermi level evanescent behavior in the occupation energies is observed in similar fashion to the occupation numbers of the 1RDM. A direct comparison with total energy differences demonstrates a quantita- tive connection between the occupation energies and electron addition and removal energies for the electron gas. For the oxygen atom, the association between the ground state occupation energies and particle addition and removal energies becomes only qualitative. The energy density matrix provides a new avenue for describing energetics with quantum Monte Carlo methods which have traditionally been limited to total energies.

  10. Reductions in entree energy density increase children's vegetable intake and reduce energy intake

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The energy density (ED; kcal/g) of an entrée influences children's energy intake (EI), but the effect of simultaneously changing both ED and portion size of an entrée on preschool children's EI is unknown. In this within-subject crossover study, 3- to 5-year-old children (30 boys, 31 girls) in a day...

  11. High Energy Density Science at the Linac Coherent Light Source

    SciTech Connect

    Lee, R W

    2007-10-19

    High energy density science (HEDS), as a discipline that has developed in the United States from National Nuclear Security Agency (NNSA)-sponsored laboratory research programs, is, and will remain, a major component of the NNSA science and technology strategy. Its scientific borders are not restricted to NNSA. 'Frontiers in High Energy Density Physics: The X-Games of Contemporary Science' identified numerous exciting scientific opportunities in this field, while pointing to the need for a overarching interagency plan for its evolution. Meanwhile, construction of the first x-ray free-electron laser, the Office-of-Science-funded Linear Coherent Light Source-LCLS: the world's first free electron x-ray laser, with 100-fsec time resolution, tunable x-ray energies, a high rep rate, and a 10 order-of-magnitude increase in brightness over any other x-ray source--led to the realization that the scientific needs of NNSA and the broader scientific community could be well served by an LCLS HEDS endstation employing both short-pulse and high-energy optical lasers. Development of this concept has been well received in the community. NNSA requested a workshop on the applicability of LCLS to its needs. 'High Energy Density Science at the LCLS: NNSA Defense Programs Mission Need' was held in December 2006. The workshop provided strong support for the relevance of the endstation to NNSA strategic requirements. The range of science that was addressed covered a wide swath of the vast HEDS phase space. The unique possibilities provided by the LCLS in areas of intense interest to NNSA Defense Programs were discussed. The areas of focus included warm dense matter and equations of state, hot dense matter, and behavior of high-pressure materials under conditions of high strain-rate and extreme dynamic loading. Development of new and advanced diagnostic techniques was also addressed. This report lays out the relevant science, as brief summaries (Ch. II), expanded descriptions (Ch. V), and a

  12. Observations of shear flows in high-energy-density plasmas

    NASA Astrophysics Data System (ADS)

    Harding, Eric C.

    The research discussed in this thesis represents work toward the demonstration of experimental designs for creating a Kelvin-Helmholtz (KH) unstable shear layer in a high-energy-density (HED) plasma. Such plasmas are formed by irradiating materials with several kilo-Joules of laser light over a few nanoseconds, and are defined as having an internal pressure greater than one-million atmospheres. Similar plasmas exist in laboratory fusion experiments and in the astrophysical environment. The KH instability is a fundamental fluid instability that arises when strong velocity gradients exist at the interface between two fluids. The KH instability is important because it drives the mixing of fluids and initiates the transition to turbulence in the flow. Until now, the evolution of the KH instability has remained relatively unexplored in the HED regime This thesis presents the observations and analysis of two novel experiments carried out using two separate laser facilities. The first experiment used 1.4 kJ from the Nike laser to generate a supersonic flow of Al plasma over a low-density, rippled foam surface. The Al flow interacted with the foam and created distinct features that resulted from compressible effects. In this experiment there is little evidence of the KH instability. Nevertheless, this experimental design has perhaps pioneered a new method for generating a supersonic shear flow that has the potential to produce the KH instability if more laser energy is applied. The second experiment was performed on the Omega laser. In this case 4.3 kJ of laser energy drove a blast wave along a rippled foam/plastic interface. In response to the vorticity deposited and the shear flow established by the blast wave, the interface rolls up into large vorticies characteristic of the KH instability. The Omega experiment was the first HED experiment to capture the evolution of the KH instability.

  13. Ferroelectric polymer networks with high energy density and improved discharged efficiency for dielectric energy storage.

    PubMed

    Khanchaitit, Paisan; Han, Kuo; Gadinski, Matthew R; Li, Qi; Wang, Qing

    2013-01-01

    Ferroelectric polymers are being actively explored as dielectric materials for electrical energy storage applications. However, their high dielectric constants and outstanding energy densities are accompanied by large dielectric loss due to ferroelectric hysteresis and electrical conduction, resulting in poor charge-discharge efficiencies under high electric fields. To address this long-standing problem, here we report the ferroelectric polymer networks exhibiting significantly reduced dielectric loss, superior polarization and greatly improved breakdown strength and reliability, while maintaining their fast discharge capability at a rate of microseconds. These concurrent improvements lead to unprecedented charge-discharge efficiencies and large values of the discharged energy density and also enable the operation of the ferroelectric polymers at elevated temperatures, which clearly outperforms the melt-extruded ferroelectric polymer films that represents the state of the art in dielectric polymers. The simplicity and scalability of the described method further suggest their potential for high energy density capacitors. PMID:24276519

  14. Impact of olfactory and auditory priming on the attraction to foods with high energy density.

    PubMed

    Chambaron, S; Chisin, Q; Chabanet, C; Issanchou, S; Brand, G

    2015-12-01

    \\]\\Recent research suggests that non-attentively perceived stimuli may significantly influence consumers' food choices. The main objective of the present study was to determine whether an olfactory prime (a sweet-fatty odour) and a semantic auditory prime (a nutritional prevention message), both presented incidentally, either alone or in combination can influence subsequent food choices. The experiment included 147 participants who were assigned to four different conditions: a control condition, a scented condition, an auditory condition or an auditory-scented condition. All participants remained in the waiting room during15 min while they performed a 'lure' task. For the scented condition, the participants were unobtrusively exposed to a 'pain au chocolat' odour. Those in the auditory condition were exposed to an audiotape including radio podcasts and a nutritional message. A third group of participants was exposed to both olfactory and auditory stimuli simultaneously. In the control condition, no stimulation was given. Following this waiting period, all participants moved into a non-odorised test room where they were asked to choose, from dishes served buffet-style, the starter, main course and dessert that they would actually eat for lunch. The results showed that the participants primed with the odour of 'pain au chocolat' tended to choose more desserts with high energy density (i.e., a waffle) than the participants in the control condition (p = 0.06). Unexpectedly, the participants primed with the nutritional auditory message chose to consume more desserts with high energy density than the participants in the control condition (p = 0.03). In the last condition (odour and nutritional message), they chose to consume more desserts with high energy density than the participants in the control condition (p = 0.01), and the data reveal an additive effect of the two primes. PMID:26119807

  15. Controlling activation site density by low-energy far-field stimulation in cardiac tissue

    NASA Astrophysics Data System (ADS)

    Hörning, Marcel; Takagi, Seiji; Yoshikawa, Kenichi

    2012-06-01

    Tachycardia and fibrillation are potentially fatal arrhythmias associated with the formation of rotating spiral waves in the heart. Presently, the termination of these types of arrhythmia is achieved by use of antitachycardia pacing or cardioversion. However, these techniques have serious drawbacks, in that they either have limited application or produce undesirable side effects. Low-energy far-field stimulation has recently been proposed as a superior therapy. This proposed therapeutic method would exploit the phenomenon in which the application of low-energy far-field shocks induces a large number of activation sites (“virtual electrodes”) in tissue. It has been found that the formation of such sites can lead to the termination of undesired states in the heart and the restoration of normal beating. In this study we investigate a particular aspect of this method. Here we seek to determine how the activation site density depends on the applied electric field through in vitro experiments carried out on neonatal rat cardiac tissue cultures. The results indicate that the activation site density increases exponentially as a function of the intracellular conductivity and the level of cell isotropy. Additionally, we report numerical results obtained from bidomain simulations of the Beeler-Reuter model that are quantitatively consistent with our experimental results. Also, we derive an intuitive analytical framework that describes the activation site density and provides useful information for determining the ratio of longitudinal to transverse conductivity in a cardiac tissue culture. The results obtained here should be useful in the development of an actual therapeutic method based on low-energy far-field pacing. In addition, they provide a deeper understanding of the intrinsic properties of cardiac cells.

  16. Pulsed power drivers for ICF and high energy density physics

    SciTech Connect

    Ramirez, J.J.; Matzen, M.K.; McDaniel, D.H.

    1995-12-31

    Nanosecond Pulsed Power Science and Technology has its origins in the 1960s and over the past decade has matured into a flexible and robust discipline capable of addressing key physics issues of importance to ICF and high Energy Density Physics. The major leverage provided by pulsed power is its ability to generate and deliver high energy and high power at low cost and high efficiency. A low-cost, high-efficiency driver is important because of the very large capital investment required for multi-megajoule ignition-class systems. High efficiency is of additional importance for a commercially viable inertial fusion energy option. Nanosecond pulsed power has been aggressively and successfully developed at Sandia over the past twenty years. This effort has led to the development of unique multi-purpose facilities supported by highly capable diagnostic, calculational and analytic capabilities. The Sandia Particle-beam Fusion Program has evolved as part of an integrated national ICF Program. It applies the low-cost, high-efficiency leverage provided by nanosecond pulsed power systems to the longer-term goals of the national program, i.e., the Laboratory Microfusion Facility and Inertial Fusion Energy. A separate effort has led to the application of nanosecond pulsed power to the generation of intense, high-energy laboratory x-ray sources for application to x-ray laser and radiation effects science research. Saturn is the most powerful of these sources to date. It generates {approximately}500 kilojoules of x-rays from a magnetically driven implosion (Z-pinch). This paper describes results of x-ray physics experiments performed on Saturn, plans for a new Z-pinch drive capability for PBFA-II, and a design concept for the proposed {approximately}15 MJ Jupiter facility. The opportunities for ICF-relevant research using these facilities will also be discussed.

  17. A density functional for core-valence correlation energy

    NASA Astrophysics Data System (ADS)

    Ranasinghe, Duminda S.; Frisch, Michael J.; Petersson, George A.

    2015-12-01

    A density functional, ɛCV-DFT(ρc, ρv), describing the core-valence correlation energy has been constructed as a linear combination of ɛLY Pcorr(ρc), ɛV WN5corr(ρc, ρv), ɛPBEcorr(ρc, ρv), ɛSlaterex(ρc, ρv), ɛHCTHex(ρc, ρv), ɛHFex(ρc, ρv), and F CV -DFT (" separators=" N i , Z i ) , a function of the nuclear charges. This functional, with 6 adjustable parameters, reproduces (±0.27 kcal/mol rms error) a benchmark set of 194 chemical energy changes including 9 electron affinities, 18 ionization potentials, and 167 total atomization energies covering the first- and second-rows of the periodic table. This is almost twice the rms error (±0.16 kcal/mol) obtained with CCSD(T)/MTsmall calculations, but less than half the rms error (±0.65 kcal/mol) obtained with MP2/GTlargeXP calculations, and somewhat smaller than the rms error (±0.39 kcal/mol) obtained with CCSD/MTsmall calculations. The largest positive and negative errors from ɛCV-DFT(ρc, ρv) were 0.88 and -0.75 kcal/mol with the set of 194 core-valence energy changes ranging from +3.76 kcal/mol for the total atomization energy of propyne to -9.05 kcal/mol for the double ionization of Mg. Evaluation of the ɛCV-DFT(ρc, ρv) functional requires less time than a single SCF iteration, and the accuracy is adequate for any model chemistry based on the CCSD(T) level of theory.

  18. A density functional for core-valence correlation energy.

    PubMed

    Ranasinghe, Duminda S; Frisch, Michael J; Petersson, George A

    2015-12-01

    A density functional, εCV-DFT(ρc, ρv), describing the core-valence correlation energy has been constructed as a linear combination of εLY P (corr)(ρc), εV WN5 (corr)(ρc, ρv), εPBE (corr)(ρc, ρv), εSlater (ex)(ρc, ρv), εHCTH (ex)(ρc, ρv), εHF (ex)(ρc, ρv), and FCV-DFTNi,Zi, a function of the nuclear charges. This functional, with 6 adjustable parameters, reproduces (±0.27 kcal/mol rms error) a benchmark set of 194 chemical energy changes including 9 electron affinities, 18 ionization potentials, and 167 total atomization energies covering the first- and second-rows of the periodic table. This is almost twice the rms error (±0.16 kcal/mol) obtained with CCSD(T)/MTsmall calculations, but less than half the rms error (±0.65 kcal/mol) obtained with MP2/GTlargeXP calculations, and somewhat smaller than the rms error (±0.39 kcal/mol) obtained with CCSD/MTsmall calculations. The largest positive and negative errors from εCV-DFT(ρc, ρv) were 0.88 and -0.75 kcal/mol with the set of 194 core-valence energy changes ranging from +3.76 kcal/mol for the total atomization energy of propyne to -9.05 kcal/mol for the double ionization of Mg. Evaluation of the εCV-DFT(ρc, ρv) functional requires less time than a single SCF iteration, and the accuracy is adequate for any model chemistry based on the CCSD(T) level of theory. PMID:26646873

  19. Stability of Magnetically Implode Liners for High Energy Density Experiments

    SciTech Connect

    Reinovsky, R.E.; Anderson, W.E.; Atchison, W.L.; Bartsch, R.R.; Clark, D.A.; Ekdahl, C.E.; Faehl, R.J.; Goforth, J.H.; Keinigs, R.K.; Lindemuth, I.R.; Morgan, D.; Rodriguez, G.; Tasker, D.G.; Trainor, R.J.; Shlachter, J.S.

    1998-10-18

    Magnetically imploded cylindrical metal shells (z-pinch liners) are attractive drivers for a wide variety of hydrodynamics and material properties experiments. The ultimate utility of liners depends on the acceleration of near-solid density shells to velocities exceeding 20 km/sec with good azimuthal symmetry and axial uniformity. Two pulse power systems (Ranchero and Atlas) currently operational or under development at Los Alamos provide electrical energy adequate to accelerate {approximately}50 gr. liners to 1-2 MJ/cm kinetic energy. As in all z-pinches, the outer surface of a magnetically imploded liner is unstable to magneto-Rayleigh-Taylor (RT) modes during acceleration. Large-scale distortion in the liners from RT modes growing from glide plane interactions or initial imperfections could make liners unusable for man experiments. On the other hand, material strength in the liner should, from first principles, reduce the growth rate of RT modes - and can render some combinations of wavelength and amplitude analytically stable. The growth of instabilities in both soft aluminum liners and in high strength aluminum alloy liners has been studied analytically, computationally and experimentally at liner kinetic energies up to 100 KJ/cm on the Pegasus capacitor bank using driving currents up to 12 MA.

  20. A Fresh Look at Weather Impact on Peak Electricity Demand and Energy Use of Buildings Using 30-Year Actual Weather Data

    SciTech Connect

    Hong, Tianzhen; Chang, Wen-Kuei; Lin, Hung-Wen

    2013-05-01

    Buildings consume more than one third of the world?s total primary energy. Weather plays a unique and significant role as it directly affects the thermal loads and thus energy performance of buildings. The traditional simulated energy performance using Typical Meteorological Year (TMY) weather data represents the building performance for a typical year, but not necessarily the average or typical long-term performance as buildings with different energy systems and designs respond differently to weather changes. Furthermore, the single-year TMY simulations do not provide a range of results that capture yearly variations due to changing weather, which is important for building energy management, and for performing risk assessments of energy efficiency investments. This paper employs large-scale building simulation (a total of 3162 runs) to study the weather impact on peak electricity demand and energy use with the 30-year (1980 to 2009) Actual Meteorological Year (AMY) weather data for three types of office buildings at two design efficiency levels, across all 17 ASHRAE climate zones. The simulated results using the AMY data are compared to those from the TMY3 data to determine and analyze the differences. Besides further demonstration, as done by other studies, that actual weather has a significant impact on both the peak electricity demand and energy use of buildings, the main findings from the current study include: 1) annual weather variation has a greater impact on the peak electricity demand than it does on energy use in buildings; 2) the simulated energy use using the TMY3 weather data is not necessarily representative of the average energy use over a long period, and the TMY3 results can be significantly higher or lower than those from the AMY data; 3) the weather impact is greater for buildings in colder climates than warmer climates; 4) the weather impact on the medium-sized office building was the greatest, followed by the large office and then the small

  1. THE IRON OPACITY PROJECT: High-Energy-Density Plasma Opacities

    NASA Astrophysics Data System (ADS)

    Palay, E.; Orban, C.; Nahar, S.; Pradhan, A.; Pinnsonoault, M.; Bailey, J.

    2013-05-01

    Opacity governs radiation flow in plasma sources. Accurate opacities are needed to model unobservable laboratory and astrophysical conditions. High-energy-density (HED) plasma conditions prevalent in stellar interiors can now be recreated in the laboratory. The Z-pinch fusion device at the Sandia National Lab can reproduce temperatures and densities near the boundary where radiation transport changes from diffusion to convection inside the Sun. To benchmark theoretical opacities experiments are essential to resolve the outstanding discrepancy in solar abundances. The most common volatile elements C, N, O, Ne, etc. have been spectroscopically measured to be up to 50% lower than the standard abundances. This introduces conflict in the derived values of basic solar parameters such as the radiation/convection boundary, sound speed, and the primordial He abundance with precisely measured oscillations of the Sun through Helioseismology. A potential solution is increment of stellar opacities, which has inverse but complex relation with abundacnes, at least 30%. New iron opacity calculations include hitherto neglected atomic physics of fine structure and resonances which are largely treated as lines in existing opacities calculations. Preliminary results on radiative transitions in Ne Partial support: DOE,NSF.

  2. Sodium pentazolate: A nitrogen rich high energy density material

    NASA Astrophysics Data System (ADS)

    Steele, Brad A.; Oleynik, Ivan I.

    2016-01-01

    Sodium pentazolates NaN5 and Na2N5, new high energy density materials, are discovered during first principles crystal structure search for the compounds of varying amounts of elemental sodium and nitrogen. The pentazole anion (N5-) is stabilized in the condensed phase by sodium Na+ cations at pressures exceeding 20 GPa, and becomes metastable upon release of pressure. The sodium azide (NaN3) precursor is predicted to undergo a chemical transformation above 50 GPa into sodium pentazolates NaN5 and Na2N5. The calculated Raman spectrum of NaN5 is in agreement with the experimental Raman spectrum of a previously unidentified substance appearing upon compression and heating of NaN3.

  3. Computational predictions of energy materials using density functional theory

    NASA Astrophysics Data System (ADS)

    Jain, Anubhav; Shin, Yongwoo; Persson, Kristin A.

    2016-01-01

    In the search for new functional materials, quantum mechanics is an exciting starting point. The fundamental laws that govern the behaviour of electrons have the possibility, at the other end of the scale, to predict the performance of a material for a targeted application. In some cases, this is achievable using density functional theory (DFT). In this Review, we highlight DFT studies predicting energy-related materials that were subsequently confirmed experimentally. The attributes and limitations of DFT for the computational design of materials for lithium-ion batteries, hydrogen production and storage materials, superconductors, photovoltaics and thermoelectric materials are discussed. In the future, we expect that the accuracy of DFT-based methods will continue to improve and that growth in computing power will enable millions of materials to be virtually screened for specific applications. Thus, these examples represent a first glimpse of what may become a routine and integral step in materials discovery.

  4. Aromatic Polyurea Possessing High Electrical Energy Density and Low Loss

    NASA Astrophysics Data System (ADS)

    Thakur, Yash; Lin, Minren; Wu, Shan; Zhang, Q. M.

    2016-07-01

    We report the development of a dielectric polymer, poly (ether methyl ether urea) (PEMEU), which possesses a dielectric constant of 4 and is thermally stable up to 150°C. The experimental results show that the ether units are effective in softening the rigid polymer and making it thermally processable, while the high dipole moment of urea units and glass structure of the polymer leads to a low dielectric loss and low conduction loss. As a result, PEMEU high quality thin films can be fabricated which exhibit exceptionally high breakdown field of >1.5 GV/m, and a low conduction loss at fields up to the breakdown. Consequently, the PEMEU films exhibit a high charge-discharge efficiency of 90% and a high discharged energy density of 36 J/cm3.

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

    SciTech Connect

    Professor Bruce R. Kusse; Professor David A. Hammer

    2007-04-18

    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.

  6. BUILDING A UNIVERSAL NUCLEAR ENERGY DENSITY FUNCTIONAL (UNEDF)

    SciTech Connect

    Nazarewicz, Witold

    2012-07-01

    The long-term vision initiated with UNEDF is to arrive at a comprehensive, quantitative, and unified description of nuclei and their reactions, grounded in the fundamental interactions between the constituent nucleons. We seek to replace current phenomenological models of nuclear structure and reactions with a well-founded microscopic theory that delivers maximum predictive power with well-quantified uncertainties. Specifically, the mission of this project has been three-fold: First, to find an optimal energy density functional (EDF) using all our knowledge of the nucleonic Hamiltonian and basic nuclear properties. Second, to apply the EDF theory and its extensions to validate the functional using all the available relevant nuclear structure and reaction data. Third, to apply the validated theory to properties of interest that cannot be measured, in particular the properties needed for reaction theory.

  7. Ammonia-(Dinitramido)boranes: High-Energy-Density Materials.

    PubMed

    Bélanger-Chabot, Guillaume; Rahm, Martin; Haiges, Ralf; Christe, Karl O

    2015-09-28

    Two ammonia-(dinitramido)boranes were synthesized by the reaction of dinitroamine with ammonia-borane. These compounds are the first reported examples of (dinitramido)boranes. Ammonia-mono(dinitramido)borane is a perfectly oxygen-balanced high-energy-density material (HEDM) composed of an ammonia-BH2 fuel group and a strongly oxidizing dinitramido ligand. Although it is thermally not stable enough for practical applications, its predicted specific impulse as a solid rocket propellant would be 333 s. Its predicted performance as an explosive matches that of pentaerythtritol tetranitrate (PETN) and significantly exceeds that of trinitrotoluene (TNT). Its structure was established by X-ray crystallography and vibrational and multinuclear NMR spectroscopy. Additionally, the over-oxidized ammoniabis(dinitramido)borane was detected by NMR spectroscopy. PMID:26276906

  8. HIGH ENERGY DENSITY PHYSICS EXPERIMENTS WITH INTENSE HEAVY ION BEAMS

    SciTech Connect

    Henestroza, E.; Leitner, M.; Logan, B.G.; More, R.M.; Roy, P.K.; Ni, P.; Seidl, P.A.; Waldron, W.L.; Barnard, J.J.

    2010-03-16

    The US heavy ion fusion science program has developed techniques for heating ion-beam-driven warm dense matter (WDM) targets. The WDM conditions are to be achieved by combined longitudinal and transverse space-charge neutralized drift compression of the ion beam to provide a hot spot on the target with a beam spot size of about 1 mm, and pulse length about 1-2 ns. As a technique for heating volumetric samples of matter to high energy density, intense beams of heavy ions are capable of delivering precise and uniform beam energy deposition dE/dx, in a relatively large sample size, and the ability to heat any solid-phase target material. Initial experiments use a 0.3 MeV K+ beam (below the Bragg peak) from the NDCX-I accelerator. Future plans include target experiments using the NDCX-II accelerator, which is designed to heat targets at the Bragg peak using a 3-6 MeV lithium ion beam. The range of the beams in solid matter targets is about 1 micron, which can be lengthened by using porous targets at reduced density. We have completed the fabrication of a new experimental target chamber facility for WDM experiments, and implemented initial target diagnostics to be used for the first target experiments in NDCX-1. The target chamber has been installed on the NDCX-I beamline. The target diagnostics include a fast multi-channel optical pyrometer, optical streak camera, VISAR, and high-speed gated cameras. Initial WDM experiments will heat targets by compressed NDCX-I beams and will explore measurement of temperature and other target parameters. Experiments are planned in areas such as dense electronegative targets, porous target homogenization and two-phase equation of state.

  9. HIGH ENERGY DENSITY PHYSICS EXPERIMENTS WITH INTENSE HEAVY ION BEAMS

    SciTech Connect

    Bieniosek, F.M.; Henestroza, E.; Leitner, M.; Logan, B.G.; More, R.M.; Roy, P.K.; Ni, P.; Seidl, P.A.; Waldron, W.L.; Barnard, J.J.

    2008-08-01

    The US heavy ion fusion science program has developed techniques for heating ion-beam-driven warm dense matter (WDM) targets. The WDM conditions are to be achieved by combined longitudinal and transverse space-charge neutralized drift compression of the ion beam to provide a hot spot on the target with a beam spot size of about 1 mm, and pulse length about 1-2 ns. As a technique for heating volumetric samples of matter to high energy density, intense beams of heavy ions are capable of delivering precise and uniform beam energy deposition dE/dx, in a relatively large sample size, and the ability to heat any solid-phase target material. Initial experiments use a 0.3 MeV K+ beam (below the Bragg peak) from the NDCX-I accelerator. Future plans include target experiments using the NDCX-II accelerator, which is designed to heat targets at the Bragg peak using a 3-6 MeV lithium ion beam. The range of the beams in solid matter targets is about 1 micron, which can be lengthened by using porous targets at reduced density. We have completed the fabrication of a new experimental target chamber facility for WDM experiments, and implemented initial target diagnostics to be used for the first target experiments in NDCX-1. The target chamber has been installed on the NDCX-I beamline. The target diagnostics include a fast multi-channel optical pyrometer, optical streak camera, VISAR, and high-speed gated cameras. Initial WDM experiments will heat targets by compressed NDCX-I beams and will explore measurement of temperature and other target parameters. Experiments are planned in areas such as dense electronegative targets, porous target homogenization and two-phase equation of state.

  10. Fabrication and demonstration of high energy density lithium ion microbatteries

    NASA Astrophysics Data System (ADS)

    Sun, Ke

    density on a limited footprint area. In chapter 4, Li-ion batteries based on the LiMn2O4-TiP 2O7 couple are manufactured on flexible paper substrates; where the use of light-weight paper substrates significantly increase the gravimetric energy density of this electrode couple as compared to traditional metal current collectors. In chapter 5, a novel nanowire growth mechanism will be explored to grow interdigitated metal oxide nanowire micro battery electrodes. The growth kinetics of this mechanism is systematically studied to understand how to optimize the growth process to produce electrodes with improved electrochemical properties.

  11. Frontiers in plasma science: a high energy density perspective

    NASA Astrophysics Data System (ADS)

    Remington, Bruce

    2015-11-01

    The potential for ground-breaking research in plasma physics in high energy density (HED) regimes is compelling. The combination of HED facilities around the world spanning microjoules to megajoules, with time scales ranging from femtoseconds to microseconds enables new regimes of plasma science to be experimentally probed. The ability to shock and ramp compress samples and simultaneously probe them allows dense, strongly coupled, Fermi degenerate plasmas relevant to planetary interiors to be studied. Shock driven hydrodynamic instabilities evolving into turbulent flows relevant to the dynamics of exploding stars are being probed. The physics and dynamics of magnetized plasmas relevant to astrophysics and inertial confinement fusion are also starting to be studied. High temperature, high velocity interacting flows are being probed for evidence of astrophysical collisionless shock formation. Turbulent, high magnetic Reynolds number flows are being experimentally generated to look for evidence of the turbulent magnetic dynamo effect. And new results from thermonuclear reactions in dense hot plasmas relevant to stellar interiors are starting to emerge. A selection of examples providing a compelling vision for frontier plasma science in the coming decade will be presented. This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  12. Metrology Challenges for High Energy Density Science Target Manufacture

    SciTech Connect

    Seugling, R M; Bono, M J; Davis, P

    2009-02-19

    Currently, High Energy Density Science (HEDS) experiments are used to support and qualify predictive physics models. These models assume ideal conditions such as energy (input) and device (target) geometry. The experiments rely on precision targets constructed from components with dimensions in the millimeter range, while having micrometer-scale, functional features, including planar steps, sine waves, and step-joint geometry on hemispherical targets. Future target designs will likely have features and forms that rival or surpass current manufacturing and characterization capability. The dimensional metrology of these features is important for a number of reasons, including qualification of sub-components prior to assembly, quantification of critical features on the as-built assemblies and as a feedback mechanism for fabrication process development. Variations in geometry from part to part can lead to functional limitations, such as unpredictable instabilities during an experiment and the inability to assemble a target from poorly matched sub-components. Adding to the complexity are the large number and variety of materials, components, and shapes that render any single metrology technique difficult to use with low uncertainty. Common materials include metal and glass foams, doped transparent and opaque plastics and a variety of deposited and wrought metals. A suite of metrology tools and techniques developed to address the many critical issues relevant to the manufacture of HEDS targets including interferometry, x-ray radiography and contact metrology are presented including two sided interferometry for absolute thickness metrology and low force probe technology for micrometer feature coordinate metrology.

  13. Thermal transport measurements in high-energy-density matter

    NASA Astrophysics Data System (ADS)

    Ping, Yuan

    2015-11-01

    Thermal conductivity is one of the most fundamental physical properties of matter. It determines the heat transport rate and has an enormous impact on a variety of mechanical, electrical, chemical, and nuclear systems. Thermal conduction is important in high energy density (HED) matter such as laboratory fusion plasmas, planetary cores, compact stars, and other celestial objects. Examples are in the ablation and instability growth in inertial confinement fusion (ICF) capsules, in energy loss from ICF hot spot, and in the evolution of Earth's core-mantle boundary. Despite the importance of thermal conductivity in HED systems, experimental measurements under relevant conditions are scarce and challenging. We have developed a method of differential heating for thermal conductivity measurements. In this talk, experimental designs will be described for four different platforms: optical laser heating, proton heating, laser-generated x-ray heating and XFEL heating. Data from various facilities will be presented and comparison with models will be discussed. This work was performed under DOE contract DE-AC52-07NA27344 with support from OFES Early Career program and LLNL LDRD program.

  14. Comment on "Single-point kinetic energy density functionals: A pointwise kinetic energy density analysis and numerical convergence investigation"

    NASA Astrophysics Data System (ADS)

    Trickey, S. B.; Karasiev, Valentin V.; Chakraborty, Debajit

    2015-09-01

    We suggest a more nuanced view of the merit and utility of generalized gradient approximations (GGAs) for the noninteracting kinetic energy (KE) than the critique of Xia and Carter (XC) [Phys. Rev. B 91, 045124 (2015), 10.1103/PhysRevB.91.045124]. Specifically, the multiple valuedness of the Pauli term enhancement factor (denoted G [n ] by XC) with respect to the inhomogeneity variable s can be excluded by enforcement of a bound on the Kohn-Sham KE to achieve universality of the functional along with enforcement of proper large-s behavior. This is physically sensible in that the excluded G values occur for s values that correspond to low densities. The behavior is exacerbated by peculiarities of pseudodensities. The VT84F KE GGA, constructed with these constraints, does not have the numerical instability in our older PBE2 functional analyzed by XC.

  15. Testing an Energy Balance Model for Estimating Actual Evapotranspiration Using Remotely Sensed Data. [Hannover, West Germany barley and wheat fields

    NASA Technical Reports Server (NTRS)

    Gurney, R. J.; Camillo, P. J.

    1985-01-01

    An energy-balance model is used to estimate daily evapotranspiration for 3 days for a barley field and a wheat field near Hannover, Federal Republic of Germany. The model was calibrated using once-daily estimates of surface temperatures, which may be remotely sensed. The evaporation estimates were within the 95% error bounds of independent eddy correlation estimates for the daytime periods for all three days for both sites, but the energy-balance estimates are generally higher; it is unclear which estimate is biassed. Soil moisture in the top 2 cm of soil, which may be remotely sensed, may be used to improve these evaporation estimates under partial ground cover. Sensitivity studies indicate the amount of ground data required is not excessive.

  16. A coupled remote sensing and the Surface Energy Balance with Topography Algorithm (SEBTA) to estimate actual evapotranspiration under complex terrain

    NASA Astrophysics Data System (ADS)

    Gao, Z. Q.; Liu, C. S.; Gao, W.; Chang, N. B.

    2010-07-01

    Evapotranspiration (ET) may be used as an ecological indicator to address the ecosystem complexity. The accurate measurement of ET is of great significance for studying environmental sustainability, global climate changes, and biodiversity. Remote sensing technologies are capable of monitoring both energy and water fluxes on the surface of the Earth. With this advancement, existing models, such as SEBAL, S_SEBI and SEBS, enable us to estimate the regional ET with limited temporal and spatial scales. This paper extends the existing modeling efforts with the inclusion of new components for ET estimation at varying temporal and spatial scales under complex terrain. Following a coupled remote sensing and surface energy balance approach, this study emphasizes the structure and function of the Surface Energy Balance with Topography Algorithm (SEBTA). With the aid of the elevation and landscape information, such as slope and aspect parameters derived from the digital elevation model (DEM), and the vegetation cover derived from satellite images, the SEBTA can fully account for the dynamic impacts of complex terrain and changing land cover in concert with some varying kinetic parameters (i.e., roughness and zero-plane displacement) over time. Besides, the dry and wet pixels can be recognized automatically and dynamically in image processing thereby making the SEBTA more sensitive to derive the sensible heat flux for ET estimation. To prove the application potential, the SEBTA was carried out to present the robust estimates of 24 h solar radiation over time, which leads to the smooth simulation of the ET over seasons in northern China where the regional climate and vegetation cover in different seasons compound the ET calculations. The SEBTA was validated by the measured data at the ground level. During validation, it shows that the consistency index reached 0.92 and the correlation coefficient was 0.87.

  17. A coupled remote sensing and the Surface Energy Balance with Topography Algorithm (SEBTA) to estimate actual evapotranspiration over heterogeneous terrain

    NASA Astrophysics Data System (ADS)

    Gao, Z. Q.; Liu, C. S.; Gao, W.; Chang, N.-B.

    2011-01-01

    Evapotranspiration (ET) may be used as an ecological indicator to address the ecosystem complexity. The accurate measurement of ET is of great significance for studying environmental sustainability, global climate changes, and biodiversity. Remote sensing technologies are capable of monitoring both energy and water fluxes on the surface of the Earth. With this advancement, existing models, such as SEBAL, S_SEBI and SEBS, enable us to estimate the regional ET with limited temporal and spatial coverage in the study areas. This paper extends the existing modeling efforts with the inclusion of new components for ET estimation at different temporal and spatial scales under heterogeneous terrain with varying elevations, slopes and aspects. Following a coupled remote sensing and surface energy balance approach, this study emphasizes the structure and function of the Surface Energy Balance with Topography Algorithm (SEBTA). With the aid of the elevation and landscape information, such as slope and aspect parameters derived from the digital elevation model (DEM), and the vegetation cover derived from satellite images, the SEBTA can account for the dynamic impacts of heterogeneous terrain and changing land cover with some varying kinetic parameters (i.e., roughness and zero-plane displacement). Besides, the dry and wet pixels can be recognized automatically and dynamically in image processing thereby making the SEBTA more sensitive to derive the sensible heat flux for ET estimation. To prove the application potential, the SEBTA was carried out to present the robust estimates of 24 h solar radiation over time, which leads to the smooth simulation of the ET over seasons in northern China where the regional climate and vegetation cover in different seasons compound the ET calculations. The SEBTA was validated by the measured data at the ground level. During validation, it shows that the consistency index reached 0.92 and the correlation coefficient was 0.87.

  18. Characterizing high-energy-density propellants for space propulsion applications

    NASA Astrophysics Data System (ADS)

    Kokan, Timothy

    There exists wide ranging research interest in high-energy-density matter (HEDM) propellants as a potential replacement for existing industry standard fuels for liquid rocket engines. The U.S. Air Force Research Laboratory, the U.S. Army Research Lab, the NASA Marshall Space Flight Center, and the NASA Glenn Research Center each either recently concluded or currently has ongoing programs in the synthesis and development of these potential new propellants. In order to perform conceptual designs using these new propellants, most conceptual rocket engine powerhead design tools (e.g. NPSS, ROCETS, and REDTOP-2) require several thermophysical properties of a given propellant over a wide range of temperature and pressure. These properties include enthalpy, entropy, density, viscosity, and thermal conductivity. Very little thermophysical property data exists for most of these potential new HEDM propellants. Experimental testing of these properties is both expensive and time consuming and is impractical in a conceptual vehicle design environment. A new technique for determining these thermophysical properties of potential new rocket engine propellants is presented. The technique uses a combination of three different computational methods to determine these properties. Quantum mechanics and molecular dynamics are used to model new propellants at a molecular level in order to calculate density, enthalpy, and entropy. Additivity methods are used to calculate the kinematic viscosity and thermal conductivity of new propellants. This new technique is validated via a series of verification experiments of HEDM compounds. Results are provided for two HEDM propellants: quadricyclane and 2-azido-N,N-dimethylethanamine (DMAZ). In each case, the new technique does a better job than the best current computational methods at accurately matching the experimental data of the HEDM compounds of interest. A case study is provided to help quantify the vehicle level impacts of using HEDM

  19. Phenomenological calculation of nuclear binding energy and density with Yukawa-potentials

    NASA Astrophysics Data System (ADS)

    Scheid, W.

    2016-01-01

    In this paper, we study a phenomenological collective model for the calculation of the nuclear density and ground state binding energy of nuclei. The proton density is assumed proportional to the nuclear density. The total binding energy of the nuclear matter consists of the binding energy of infinite nuclear matter, of two Yukawa-potentials, of the Coulomb-energy and of the symmetry-energy. The parameters of the Yukawa-potential are fitted with the Bethe-Weizsäcker (BW) mass formula. The resulting binding energies and nuclear densities agree quite satisfying with known nuclear values.

  20. Tensor part of the Skyrme energy density functional: Spherical nuclei

    NASA Astrophysics Data System (ADS)

    Lesinski, T.; Bender, M.; Bennaceur, K.; Duguet, T.; Meyer, J.

    2007-07-01

    the single-particle spectra in doubly-magic nuclei is deteriorated, which can be traced back to features of the single-particle spectra that are not related to the tensor terms. We conclude that the currently used central and spin-orbit parts of the Skyrme energy density functional are not flexible enough to allow for the presence of large tensor terms.

  1. Atlas Pulsed Power Facility for High Energy Density Physics Experiments

    SciTech Connect

    Miller, R.B.; Ballard, E.O.; Barr, G.W.; Bowman, D.W.; Chochrane, J.C.; Davis, H.A.; Elizondo, J.M.; Gribble, R.F.; Griego, J.R.; Hicks, R.D.; Hinckley, W.B.; Hosack, K.W.; Nielsen, K.E.; Parker, J.V.; Parsons, M.O.; Rickets, R.L.; Salazar, H.R.; Sanchez, P.G.; Scudder, D.W.; Shapiro, C.; Thompson, M.C.; Trainor, R.J.; Valdez, G.A.; Vigil, B.N.; Watt, R.G.; Wysock, F.J.

    1999-06-07

    The Atlas facility, now under construction at Los Alamos National Laboratory (LANL), will provide a unique capability for performing high-energy-density experiments in support of weapon-physics and basic-research programs. It is intended to be an international user facility, providing opportunities for researchers from national laboratories and academic institutions around the world. Emphasizing institutions around the world. Emphasizing hydrodynamic experiments, Atlas will provide the capability for achieving steady shock pressures exceeding 10-Mbar in a volume of several cubic centimeters. In addition, the kinetic energy associated with solid liner implosion velocities exceeding 12 km/s is sufficient to drive dense, hydrodynamic targets into the ionized regime, permitting the study of complex issues associated with strongly-coupled plasmas. The primary element of Atlas is a 23-MJ capacitor bank, comprised of 96 separate Marx generators housed in 12 separate oil-filled tanks, surrounding a central target chamber. Each tank will house two, independently-removable maintenance units, with each maintenance unit consisting of four Marx modules. Each Marx module has four capacitors that can each be charged to a maximum of 60 kilovolts. When railgap switches are triggered, the marx modules erect to a maximum of 240 kV. The parallel discharge of these 96 Marx modules will deliver a 30-MA current pulse with a 4-5-{micro}s risetime to a cylindrical, imploding liner via 24 vertical, tri-plate, oil-insulated transmission lines. An experimental program for testing and certifying all Marx and transmission line components has been completed. A complete maintenance module and its associated transmission line (the First Article) are now under construction and testing. The current Atlas schedule calls for construction of the machine to be complete by August, 2000. Acceptance testing is scheduled to begin in November, 2000, leading to initial operations in January, 2001.

  2. High Energy Density Studies at the OMEGA laser facility

    NASA Astrophysics Data System (ADS)

    Boehly, Thomas

    2015-06-01

    The primary emphasis of the scientific program at the Laboratory for Laser Energetics is laser-driven inertial confinement fusion. We report on high-energy-density (HED) experiments that use the OMEGA laser to produce multi-megabar shocks in materials of interest to the national fusion effort and the associated HED sciences. We present measurements of the behavior of shocked diamond, in both the single-crystal and ultranano-crystalline forms used as an ablator material in fusion capsules. Using the impedance-matching technique both the Hugoniot and release behaviors are measured with respect to multiple reference materials. The release of shocked diamond into liquid deuterium is also measured. We present the results of sound-speed measurements in shocked quartz which is also used as a reference for sound speed measurements in CH and fused silica. This is done using an unsteady wave analysis that tracks the propagation of small perturbations in shock pressure as they traverse the shocked material from `piston' to shock front. The arrival times of these perturbations, as compared to the same in a reference material, provides the sound speed in the shock material. We also present results of optical and x-ray probing of shock waves in foam targets and solid targets, as well as the release plumes of shock material after shock breakout. The import of these measurements to the fusion program and basic HED science will be discussed and plans for future work presented. This work was supported by the U.S. Department of Energy Office of Inertial Confinement Fusion under Cooperative Agreement No. DE-FC52-08NA28302.

  3. Upgrading of biorenewables to high energy density fuels

    SciTech Connect

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

    2010-12-07

    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.

  4. Replacing critical rare earth materials in high energy density magnets

    NASA Astrophysics Data System (ADS)

    McCallum, R. William

    2012-02-01

    High energy density permanent magnets are crucial to the design of internal permanent magnet motors (IPM) for hybride and electric vehicles and direct drive wind generators. Current motor designs use rare earth permanent magnets which easily meet the performance goals, however, the rising concerns over cost and foreign control of the current supply of rare earth resources has motivated a search for non-rare earth based permanent magnets alloys with performance metrics which allow the design of permanent magnet motors and generators without rare earth magnets. This talk will discuss the state of non-rare-earth permanent magnets and efforts to both improve the current materials and find new materials. These efforts combine first principles calculations and meso-scale magnetic modeling with advance characterization and synthesis techniques in order to advance the state of the art in non rare earth permanent magnets. The use of genetic algorithms in first principle structural calculations, combinatorial synthesis in the experimental search for materials, atom probe microscopy to characterize grain boundaries on the atomic level, and other state of the art techniques will be discussed. In addition the possibility of replacing critical rare earth elements with the most abundant rare earth Ce will be discussed.

  5. Plasma polymerized high energy density dielectric films for capacitors

    NASA Technical Reports Server (NTRS)

    Yamagishi, F. G.

    1983-01-01

    High energy density polymeric dielectric films were prepared by plasma polymerization of a variety of gaseous monomers. This technique gives thin, reproducible, pinhole free, conformable, adherent, and insoluble coatings and overcomes the processing problems found in the preparation of thin films with bulk polymers. Thus, devices are prepared completely in a vacuum environment. The plasma polymerized films prepared all showed dielectric strengths of greater than 1000 kV/cm and in some cases values of greater than 4000 kV/cm were observed. The dielectric loss of all films was generally less than 1% at frequencies below 10 kHz, but this value increased at higher frequencies. All films were self healing. The dielectric strength was a function of the polymerization technique, whereas the dielectric constant varied with the structure of the starting material. Because of the thin films used (thickness in the submicron range) surface smoothness of the metal electrodes was found to be critical in obtaining high dielectric strengths. High dielectric strength graft copolymers were also prepared. Plasma polymerized ethane was found to be thermally stable up to 150 C in the presence of air and 250 C in the absence of air. No glass transitions were observed for this material.

  6. Building A Universal Nuclear Energy Density Functional (UNEDF)

    SciTech Connect

    Joe Carlson; Dick Furnstahl; Mihai Horoi; Rusty Lusk; Witek Nazarewicz; Esmond Ng; Ian Thompson; James Vary

    2012-09-30

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

  7. Experimental measurement of energy density in a vibrating plate and comparison with energy finite element analysis

    NASA Astrophysics Data System (ADS)

    Navazi, H. M.; Nokhbatolfoghahaei, A.; Ghobad, Y.; Haddadpour, H.

    2016-08-01

    In this paper, a new method and formulation is presented for experimental measurement of energy density of high frequency vibrations of a plate. By use of the new proposed method and eight accelerometers, both kinetic and potential energy densities are measured. Also, a computer program is developed based on energy finite element method to evaluate the proposed method. For several points, the results of the developed experimental formulation are compared with those of the energy finite element analysis results. It is observed that, there is a good agreement between experimental results and analyses. Finally, another test setup with reduced accelerometer spacing was prepared and based on the comparison between kinetic and potential results, it is concluded that, the kinetic and potential counterparts of the energy density are equal in high frequency bands. Based on this conclusion, the measurement procedure was upgraded to an efficient and very simple one for high frequency ranges. According to the new test procedure, another experimental measurement was performed and the results had a good agreement with the EFEA results.

  8. High-energy-density electron jet generation from an opening gold cone filled with near-critical-density plasma

    SciTech Connect

    Yu, T. P. Shao, F. Q.; Zou, D. B.; Ge, Z. Y.; Zhang, G. B.; Wang, W. Q.; Li, X. H.; Liu, J. X.; Ouyang, J. M.; Yu, W.; Luan, S. X.; Wang, J. W.; Wong, A. Y.

    2015-01-14

    By using two-dimensional particle-in-cell simulations, we propose a scheme for strong coupling of a petawatt laser with an opening gold cone filled with near-critical-density plasmas. When relevant parameters are properly chosen, most laser energy can be fully deposited inside the cone with only 10% leaving the tip opening. Due to the asymmetric ponderomotive acceleration by the strongly decayed laser pulse, high-energy-density electrons with net laser energy gain are accumulated inside the cone, which then stream out of the tip opening continuously, like a jet. The jet electrons are fully relativistic, with speeds around 0.98−0.998 c and densities at 10{sup 20}/cm{sup 3} level. The jet can keep for a long time over 200 fs, which may have diverse applications in practice.

  9. Energy density analysis (EDA) of cis, trans-enol isomerization in malonaldehyde, tropolone and 9-hydroxyphenalenone

    NASA Astrophysics Data System (ADS)

    Nakai, Hiromi; Sodeyama, Keitaro

    2002-10-01

    We have recently proposed an energy density analysis (EDA) that partitions the total energy of a molecular system into atomic energy densities. In this study, the EDA is applied to cis, trans-enol isomerization reactions of malonaldehyde, tropolone and 9-hydroxyphenalenone. Energy density changes in the reactions are shown to be closely related to the formation and breaking of the chemical bonds. By analyzing the energy density changes, we can find the reason why the hydrogen atom moves through the out-of-plane pathway instead of the in-plane pathway.

  10. Symmetry energy at subnuclear densities and nuclei in neutron star crusts

    SciTech Connect

    Oyamatsu, Kazuhiro; Iida, Kei

    2007-01-15

    We examine how the properties of inhomogeneous nuclear matter at subnuclear densities depend on the density dependence of the symmetry energy. Using a macroscopic nuclear model we calculate the size and shape of nuclei in neutron star matter at zero temperature in a way dependent on the density dependence of the symmetry energy. We find that for smaller symmetry energy at subnuclear densities, corresponding to the larger density symmetry coefficient L, the charge number of nuclei is smaller and the critical density at which matter with nuclei or bubbles becomes uniform is lower. The decrease in the charge number is associated with the dependence of the surface tension on the nuclear density and the density of a sea of neutrons, whereas the decrease in the critical density can be generally understood in terms of proton clustering instability in uniform matter.

  11. Transverse energy scaling and energy density estimates from sup 16 O- and sup 32 S-induced reactions

    SciTech Connect

    Not Available

    1989-01-01

    We discuss the dependence of transverse energy production on projectile mass, target mass, and on the impact parameter of the heavy ion reaction. The transverse energy is shown to scale with the number of participating nucleons. Various methods to estimate the attained energy density from the observed transverse energy are discussed. It is shown that the systematics of the energy density estimates suggest averages of 2--3 GeV/fm{sup 3} rather than the much higher values attained by assuming Landau-stopping initial conditions. Based on the observed scaling of the transverse energy, an initial energy density profile may be estimated. 14 refs., 4 figs.

  12. Transverse energy scaling and energy density estimates from /sup 16/O- and /sup 32/S-induced reactions

    SciTech Connect

    Awes, T.C.; Albrecht, R.; Baktash, C.; Beckmann, P.; Berger, F.; Bock, R.; Claesson, G.; Clewing, G.; Dragon, L.; Eklund, A.

    1989-01-01

    We discuss the dependence of transverse energy production on projectile mass, target mass, and on the impact parameter of the heavy ion reaction. The transverse energy is shown to scale with the number of participating nucleons. Various methods to estimate the attained energy density from the observed transverse energy are discussed. It is shown that the systematics of the energy density estimates suggest average of 2-3 GeV/fm/sup 3/ rather than the much higher values attained by assuming Landau-stopping initial conditions. Based on the observed scaling of the transverse energy, an initial energy density profile may be estimated. 11 refs., 4 figs.

  13. A generalized model for estimating the energy density of invertebrates

    USGS Publications Warehouse

    James, Daniel A.; Csargo, Isak J.; Von Eschen, Aaron; Thul, Megan D.; Baker, James M.; Hayer, Cari-Ann; Howell, Jessica; Krause, Jacob; Letvin, Alex; Chipps, Steven R.

    2012-01-01

    Invertebrate energy density (ED) values are traditionally measured using bomb calorimetry. However, many researchers rely on a few published literature sources to obtain ED values because of time and sampling constraints on measuring ED with bomb calorimetry. Literature values often do not account for spatial or temporal variability associated with invertebrate ED. Thus, these values can be unreliable for use in models and other ecological applications. We evaluated the generality of the relationship between invertebrate ED and proportion of dry-to-wet mass (pDM). We then developed and tested a regression model to predict ED from pDM based on a taxonomically, spatially, and temporally diverse sample of invertebrates representing 28 orders in aquatic (freshwater, estuarine, and marine) and terrestrial (temperate and arid) habitats from 4 continents and 2 oceans. Samples included invertebrates collected in all seasons over the last 19 y. Evaluation of these data revealed a significant relationship between ED and pDM (r2  =  0.96, p < 0.0001), where ED (as J/g wet mass) was estimated from pDM as ED  =  22,960pDM − 174.2. Model evaluation showed that nearly all (98.8%) of the variability between observed and predicted values for invertebrate ED could be attributed to residual error in the model. Regression of observed on predicted values revealed that the 97.5% joint confidence region included the intercept of 0 (−103.0 ± 707.9) and slope of 1 (1.01 ± 0.12). Use of this model requires that only dry and wet mass measurements be obtained, resulting in significant time, sample size, and cost savings compared to traditional bomb calorimetry approaches. This model should prove useful for a wide range of ecological studies because it is unaffected by taxonomic, seasonal, or spatial variability.

  14. Covariant energy density functionals: The assessment of global performance across the nuclear landscape

    SciTech Connect

    Afanasjev, A. V.

    2015-10-15

    The assessment of the global performance of the state-of-the-art covariant energy density functionals and related theoretical uncertainties in the description of ground state observables has recently been performed. Based on these results, the correlations between global description of binding energies and nuclear matter properties of covariant energy density functionals have been studied in this contribution.

  15. Change in dietary energy density after implementation of the Texas Public School Nutrition Policy

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Consumption of energy-dense foods has been associated with rising obesity rates and the metabolic syndrome. Reducing dietary energy density is an important strategy to address obesity, but few studies have examined the effect of nutrition policies on children's energy density. The study's objective ...

  16. Talbot-Lau X-ray Deflectometer electron density diagnostic for laser and pulsed power high energy density plasma experiments

    DOE PAGESBeta

    Valdivia, M. P.; Stutman, D.; Stoeckl, C.; Mileham, C.; Begishev, I.; Theobald, W.; Bromage, J.; Regan, S. P.; Klein, S. R.; Munoz-Cordoves, G.; et al

    2016-04-21

    Talbot-Lau X-ray Deflectometry has been developed as an electron density diagnostic for High Energy Density plasmas. The technique can deliver x-ray refraction, attenuation, elemental composition, and scatter information from a single Moiré image. An 8 keV Talbot-Lau interferometer was deployed using laser and x-pinch backlighters. Grating survival and electron density mapping was demonstrated for 25-29 J, 8-30 ps laser pulses using copper foil targets. Moire pattern formation and grating survival was also observed using a copper x-pinch driven at 400 kA, ~1 kA/ns. Lastly, these results demonstrate the potential of TXD as an electron density diagnostic for HED plasmas.

  17. High-energy-density electron beam from interaction of two successive laser pulses with subcritical-density plasma

    NASA Astrophysics Data System (ADS)

    Wang, J. W.; Yu, W.; Yu, M. Y.; Xu, H.; Ju, J. J.; Luan, S. X.; Murakami, M.; Zepf, M.; Rykovanov, S.

    2016-02-01

    It is shown by particle-in-cell simulations that a narrow electron beam with high energy and charge density can be generated in a subcritical-density plasma by two consecutive laser pulses. Although the first laser pulse dissipates rapidly, the second pulse can propagate for a long distance in the thin wake channel created by the first pulse and can further accelerate the preaccelerated electrons therein. Given that the second pulse also self-focuses, the resulting electron beam has a narrow waist and high charge and energy densities. Such beams are useful for enhancing the target-back space-charge field in target normal sheath acceleration of ions and bremsstrahlung sources, among others.

  18. Fluctuations of energy density of short-pulse optical radiation in the turbulent atmosphere.

    PubMed

    Banakh, V A; Smalikho, I N

    2014-09-22

    Fluctuations of energy density of short-pulse optical radiation in the turbulent atmosphere have been studied based on numerical solution of the parabolic wave equation for the complex spectral amplitude of the wave field by the split-step method. It has been shown that under conditions of strong optical turbulence, the relative variance of energy density fluctuations of pulsed radiation of femtosecond duration becomes much less than the relative variance of intensity fluctuations of continuous-wave radiation. The spatial structure of fluctuations of the energy density with a decrease of the pulse duration becomes more large-scale and homogeneous. For shorter pulses the maximal value of the probability density distribution of energy density fluctuations tends to the mean value of the energy density. PMID:25321700

  19. Assessment of Cognitive Processing by Multiple Sclerosis Patients Using Electroencephalographic Energy Density Analysis

    NASA Technical Reports Server (NTRS)

    Montgomery, Leslie D.; Ku, Yu-Tsuan E.; Luna, Bernadette; Montgomery, Richard W.; Kliss, Mark (Technical Monitor)

    1997-01-01

    Recent neuropsychological studies demonstrate that cognitive dysfunction is a common symptom in patients with multiple sclerosis. In many cases the presence of cognitive impairment affects the patient's daily activities to a greater extent than would be found due to their physical disability alone. Cognitive dysfunction can have a significant impact on the quality of life of both the patient and that of their primary caregiver. Two cognitively impaired male MS patients were given a visual discrimination task before and after a one hour cooling period. The subjects were presented a series of either red or blue circles or triangles. One of these combinations, or one fourth of the stimuli, was designated as the "target" presentation. EEG was recorded from 20 scalp electrodes using a Tracor Northern 7500 EEG/ERP system. Oral and ear temperatures were obtained and recorded manually every five minutes during the one hour cooling period. The EEG ERP signatures from each series of stimuli were analyzed in the energy density domain to determine the locus of neural activity at each EEG sampling time. The first subject's ear temperature did not decrease during the cooling period. It was actually elevated approximately 0.05C by the end of the cooling period compared to his mean of control period value. In turn, Subject One's discrimination performance and cortical energy remained essentially the same after body cooling. In contrast, Subject Two's ear temperature decreased approx. 0.8C during his cooling period. Subject Two's ERROR score decreased from 12 during the precooling control period to 2 after cooling. His ENERGY value increased approximately 300%, from a precooling value of approximately 200 to a postcooling value of nearly 600.

  20. The National Ignition Facility: A New Era in High Energy Density Science

    SciTech Connect

    Moses, E

    2009-06-10

    The National Ignition Facility, the world's most energetic laser system, is now operational. This talk will describe NIF, the ignition campaign, and new opportunities in fusion energy and high energy density science enabled by NIF.

  1. 3D printed elastic honeycombs with graded density for tailorable energy absorption

    NASA Astrophysics Data System (ADS)

    Bates, Simon R. G.; Farrow, Ian R.; Trask, Richard S.

    2016-04-01

    This work describes the development and experimental analysis of hyperelastic honeycombs with graded densities, for the purpose of energy absorption. Hexagonal arrays are manufactured from thermoplastic polyurethane (TPU) via fused filament fabrication (FFF) 3D printing and the density graded by varying cell wall thickness though the structures. Manufactured samples are subject to static compression tests and their energy absorbing potential analysed via the formation of energy absorption diagrams. It is shown that by grading the density through the structure, the energy absorption profile of these structures can be manipulated such that a wide range of compression energies can be efficiently absorbed.

  2. High energy-density liquid rocket fuel performance

    NASA Technical Reports Server (NTRS)

    Rapp, Douglas C.

    1990-01-01

    A fuel performance database of liquid hydrocarbons and aluminum-hydrocarbon fuels was compiled using engine parametrics from the Space Transportation Engine Program as a baseline. Propellant performance parameters are introduced. General hydrocarbon fuel performance trends are discussed with respect to hydrogen-to-carbon ratio and heat of formation. Aluminum-hydrocarbon fuel performance is discussed with respect to aluminum metal loading. Hydrocarbon and aluminum-hydrocarbon fuel performance is presented with respect to fuel density, specific impulse and propellant density specific impulse.

  3. High energy-density liquid rocket fuel performance

    NASA Technical Reports Server (NTRS)

    Rapp, Douglas C.

    1990-01-01

    A fuel performance database of liquid hydrocarbons and aluminum-hydrocarbon fuels was compiled using engine parametrics from the Space Transportation Engine Program as a baseline. Propellant performance parameters are introduced. General hydrocarbon fuel performance trends are discussed with respect to hydrogen-to-carbon ratio and heat of formation. Aluminum-hydrocarbon fuel performance is discussed with respect to aluminum metal loading. Hydrocarbon and aluminum-hydrocarbon fuel performance is presented with respect to fuel density, specific impulse, and propellant density specific impulse.

  4. Quantitative simulation and density reconstruction in high-energy X-ray radiograph

    NASA Astrophysics Data System (ADS)

    Tang, Li; Xu, Haibo

    2014-03-01

    Numerical radiograph using Monte Carlo method is used to study fidelity of density reconstruction in high-energy X-ray radiography. A density reconstruction method for a polyenergetic X-ray source and an object composed of different materials is proposed. The method includes energy spectrum, angular spectrum and spot size of photon source. And it includes mass absorption coefficients explicitly in density reconstruction as well. A constrained conjugate gradient algorithm and variation regularization are applied to determine material edges and density reconstruction of a French test object. It shows that the method is valid for density reconstruction and energy spectrum of imaging photons is important in obtaining accurate material densities in high-energy X-ray radiograph.

  5. Energy density of lake whitefish Coregonus clupeaformis in Lakes Huron and Michigan

    USGS Publications Warehouse

    Pothoven, S.A.; Nalepa, T.F.; Madenjian, C.P.; Rediske, R.R.; Schneeberger, P.J.; He, J.X.

    2006-01-01

    We collected lake whitefish Coregonus clupeaformis off Alpena and Tawas City, Michigan, USA in Lake Huron and off Muskegon, Michigan USA in Lake Michigan during 2002–2004. We determined energy density and percent dry weight for lake whitefish from both lakes and lipid content for Lake Michigan fish. Energy density increased with increasing fish weight up to 800 g, and then remained relatively constant with further increases in fish weight. Energy density, adjusted for weight, was lower in Lake Huron than in Lake Michigan for both small (≤800 g) and large fish (>800 g). Energy density did not differ seasonally for small or large lake whitefish or between adult male and female fish. Energy density was strongly correlated with percent dry weight and percent lipid content. Based on data from commercially caught lake whitefish, body condition was lower in Lake Huron than Lake Michigan during 1981–2003, indicating that the dissimilarity in body condition between the lakes could be long standing. Energy density and lipid content in 2002–2004 in Lake Michigan were lower than data for comparable sized fish collected in 1969–1971. Differences in energy density between lakes were attributed to variation in diet and prey energy content as well as factors that affect feeding rates such as lake whitefish density and prey abundance.

  6. Constraints on the density dependence of the symmetry energy from heavy-ion collisions

    NASA Astrophysics Data System (ADS)

    Tsang, M. B.; Chajecki, Z.; Coupland, D.; Danielewicz, P.; Famiano, F.; Hodges, R.; Kilburn, M.; Lu, F.; Lynch, W. G.; Winkelbauer, J.; Youngs, M.; Zhang, Y. X.

    2011-04-01

    Constraints on the equation of state (EoS) for symmetric matter (equal neutron and proton numbers) have been extracted from energetic collisions of heavy ions over a range of energies. Collisions of neutron-deficient and neutron-rich heavy ions now provide initial constraints on the EoS of neutron-rich matter at subsaturation densities from isospin diffusions and neutron proton ratios. This article reviews the experimental constraints on the density dependence of symmetry energy at subsaturation density.

  7. Synthesis and characterization of novel high energy density capacitors for green energy

    NASA Astrophysics Data System (ADS)

    Puli, Venkata S.; Kumar, Ashok; Katiyar, Ram S.

    2011-03-01

    We have developed lead free high energy density capacitor materials, Ba(Zr 0.2 Ti 0.8) O3 (1 - x) (Ba 0.7 Ca 0.3) Ti O3 x [x = 0.10,0.15,0.20 (B ZT(1 - x) B CTx ] with high dielectric constant and moderate breakdown voltage. The ceramic materials were prepared using high energy ball milling for 4 hours at 400 rpm. The ball milled powders were calcined at 1250o C for 10hrs. Ceramic pellets having 13mm diameter were prepared using hydraulic press (2 ton) and sintered at 1400o C-1500o C for 4 hrs. X-ray diffraction studies of the sintered pellets revealed the rhombohedral/pseudo cubic crystal structure. The crystal structure was further confirmed by Raman spectra and TEM analysis. High dielectric constant and moderate polarization (~ Ps ~ 15-25 μ C/cm2) were obtained in the sintered pellets. The SEM images revealed monolithic grain growth in samples sintered at 1500o C. Preliminary data show moderate breakdown field ~ 15-20 kV/cm and energy density of 0.12-0.3 J/cm3 for all compositions. Details of the results will be presented.

  8. Chemical bonding in view of electron charge density and kinetic energy density descriptors.

    PubMed

    Jacobsen, Heiko

    2009-05-01

    Stalke's dilemma, stating that different chemical interpretations are obtained when one and the same density is interpreted either by means of natural bond orbital (NBO) and subsequent natural resonance theory (NRT) application or by the quantum theory of atoms in molecules (QTAIM), is reinvestigated. It is shown that within the framework of QTAIM, the question as to whether for a given molecule two atoms are bonded or not is only meaningful in the context of a well-defined reference geometry. The localized-orbital-locator (LOL) is applied to map out patterns in covalent bonding interaction, and produces results that are consistent for a variety of reference geometries. Furthermore, LOL interpretations are in accord with NBO/NRT, and assist in an interpretation in terms of covalent bonding. PMID:19090572

  9. Initial energy density and gluon distribution from the glasma in heavy-ion collisions

    NASA Astrophysics Data System (ADS)

    Fujii, Hirotsugu; Fukushima, Kenji; Hidaka, Yoshimasa

    2009-02-01

    We estimate the energy density and the gluon distribution associated with the classical fields describing the early-time dynamics of heavy-ion collisions. In the McLerran-Venugopalan model, we first decompose the energy density into the momentum components exactly, with the use of the Wilson line correlators. Then we evolve the energy density with the free-field equation, which is justified by the dominance of the ultraviolet modes near the collision point. We also discuss the improvement that occurs with the inclusion of nonlinear terms into the time evolution. Our numerical results at RHIC energy are fairly consistent with the empirical values.

  10. Initial energy density and gluon distribution from the glasma in heavy-ion collisions

    SciTech Connect

    Fujii, Hirotsugu; Fukushima, Kenji; Hidaka, Yoshimasa

    2009-02-15

    We estimate the energy density and the gluon distribution associated with the classical fields describing the early-time dynamics of heavy-ion collisions. In the McLerran-Venugopalan model, we first decompose the energy density into the momentum components exactly, with the use of the Wilson line correlators. Then we evolve the energy density with the free-field equation, which is justified by the dominance of the ultraviolet modes near the collision point. We also discuss the improvement that occurs with the inclusion of nonlinear terms into the time evolution. Our numerical results at RHIC energy are fairly consistent with the empirical values.

  11. Plasma (Accretion) Disks with High Magnetic Energy Densities

    NASA Astrophysics Data System (ADS)

    Rousseau, F.; Coppi, B.

    2006-04-01

    ``Corrugated'' plasma disks can form in the dominant gravity of a central object when the peak plasma pressure in the disk is of the same order as that of the pressure of the ``external'' magnetic field, while the magnetic field resulting from internal plasma currents is of the same order as the external field. The corrugation refers to a periodic variation of the plasma density in a region around the equatorial plane. The considered structure represents a transition between a ``classical'' accretion disk and a ``rings sequence'' configuration^2. The common feature of the ``corrugated'' and the ``rings sequence'' configurations is the ``crystal'' structure of the magnetic surfaces that consist of a sequence of pairs of oppositely directed toroidal current density filaments. The connection between the characteristics of these configurations and those of the marginally stable ballooning modes that can be found in a model accretion disk is pointed out and analyzed.

  12. Note: Energy convexity and density matrices in molecular systems

    NASA Astrophysics Data System (ADS)

    Bochicchio, Roberto C.; Rial, Diego

    2012-12-01

    A novel appropriate definition for the density matrix for an interacting Coulombic driven atomic or molecular system with non-integer number of particles is given. Our approach leads to a direct derivation of the proposal reported by Perdew et al. [Phys. Rev. Lett. 49, 1691 (1982)], 10.1103/PhysRevLett.49.1691 and points out its suitability and perspective advances.

  13. Hierarchy of equations for the energy functional of the density-functional theory

    NASA Astrophysics Data System (ADS)

    Nagy, Á.

    1993-04-01

    A hierarchy of equations has been derived for the energy functionals of the density-functional theory using the virial theorem and the Levy-Perdew relation. In the local-density approximation, the solution of the equations of hierarchy for the kinetic and exchange energies provides the well-known Thomas-Fermi expression for the kinetic energy and the Slater-Gáspár-Kohn-Sham expression for the exchange. The truncation of the hierarchies of the kinetic and exchange energies results in rigorous lower bounds to the kinetic energy and upper bounds to the exchange energy in the plane-wave approximation.

  14. Key Parameters Governing the Energy Density of Rechargeable Li/S Batteries.

    PubMed

    Gao, Jie; Abruña, Héctor D

    2014-03-01

    Rechargeable lithium-sulfur batteries have high theoretical capacity and energy density. However, their volumetric energy density has been believed to be lower than that of conventional lithium ion batteries employing metal oxide cathodes like LiCoO2. Here, we study the effects of sulfur loading percentage, develop a simple model and calculate the gravimetric and volumetric energy densities based on the total composition of electrodes in a lithium-sulfur cell, and compare those results with a typical graphite/LiCoO2 cell. From the model output, we have identified and established key parameters governing the energy density of rechargeable Li/S batteries. We find that the sulfur loading percentage has a much higher impact on the volumetric energy density than on the gravimetric energy density. A lithium-sulfur cell can exceed a lithium ion cell's volumetric energy density but only at high sulfur loading percentages (ca. 70%). We believe that these findings may attract more attention of lithium-sulfur system studies to high sulfur loading levels. PMID:26274082

  15. Estimation of energy density of Li-S batteries with liquid and solid electrolytes

    NASA Astrophysics Data System (ADS)

    Li, Chunmei; Zhang, Heng; Otaegui, Laida; Singh, Gurpreet; Armand, Michel; Rodriguez-Martinez, Lide M.

    2016-09-01

    With the exponential growth of technology in mobile devices and the rapid expansion of electric vehicles into the market, it appears that the energy density of the state-of-the-art Li-ion batteries (LIBs) cannot satisfy the practical requirements. Sulfur has been one of the best cathode material choices due to its high charge storage (1675 mAh g-1), natural abundance and easy accessibility. In this paper, calculations are performed for different cell design parameters such as the active material loading, the amount/thickness of electrolyte, the sulfur utilization, etc. to predict the energy density of Li-S cells based on liquid, polymeric and ceramic electrolytes. It demonstrates that Li-S battery is most likely to be competitive in gravimetric energy density, but not volumetric energy density, with current technology, when comparing with LIBs. Furthermore, the cells with polymer and thin ceramic electrolytes show promising potential in terms of high gravimetric energy density, especially the cells with the polymer electrolyte. This estimation study of Li-S energy density can be used as a good guidance for controlling the key design parameters in order to get desirable energy density at cell-level.

  16. Energy Density, Energy Intake, and Body Weight Regulation in Adults12345

    PubMed Central

    Karl, J. Philip; Roberts, Susan B.

    2014-01-01

    The role of dietary energy density (ED) in the regulation of energy intake (EI) is controversial. Methodologically, there is also debate about whether beverages should be included in dietary ED calculations. To address these issues, studies examining the effects of ED on EI or body weight in nonelderly adults were reviewed. Different approaches to calculating dietary ED do not appear to alter the direction of reported relations between ED and body weight. Evidence that lowering dietary ED reduces EI in short-term studies is convincing, but there are currently insufficient data to determine long-term effectiveness for weight loss. The review also identified key barriers to progress in understanding the role of ED in energy regulation, in particular the absence of a standard definition of ED, and the lack of data from multiple long-term clinical trials examining the effectiveness of low-ED diet recommendations for preventing both primary weight gain and weight regain in nonobese individuals. Long-term clinical trials designed to examine the impact of dietary ED on energy regulation, and including multiple ED calculation methods within the same study, are still needed to determine the importance of ED in the regulation of EI and body weight. PMID:25398750

  17. Estimation of Actual Crop ET of Paddy Using the Energy Balance Model SMARET and Validation with Field Water Balance Measurements and a Crop Growth Model (ORYZA)

    NASA Astrophysics Data System (ADS)

    Nallasamy, N. D.; Muraleedharan, B. V.; Kathirvel, K.; Narasimhan, B.

    2014-12-01

    Sustainable management of water resources requires reliable estimates of actual evapotranspiration (ET) at fine spatial and temporal resolution. This is significant in the case of rice based irrigation systems, one of the major consumers of surface water resources and where ET forms a major component of water consumption. However huge tradeoff in the spatial and temporal resolution of satellite images coupled with lack of adequate number of cloud free images within a growing season act as major constraints in deriving ET at fine spatial and temporal resolution using remote sensing based energy balance models. The scale at which ET is determined is decided by the spatial and temporal scale of Land Surface Temperature (LST) and Normalized Difference Vegetation Index (NDVI), which form inputs to energy balance models. In this context, the current study employed disaggregation algorithms (NL-DisTrad and DisNDVI) to generate time series of LST and NDVI images at fine resolution. The disaggregation algorithms aimed at generating LST and NDVI at finer scale by integrating temporal information from concurrent coarse resolution data and spatial information from a single fine resolution image. The temporal frequency of the disaggregated images is further improved by employing composite images of NDVI and LST in the spatio-temporal disaggregation method. The study further employed half-hourly incoming surface insolation and outgoing long wave radiation obtained from the Indian geostationary satellite (Kalpana-1) to convert the instantaneous ET into daily ET and subsequently to the seasonal ET, thereby improving the accuracy of ET estimates. The estimates of ET were validated with field based water balance measurements carried out in Gadana, a subbasin predominated by rice paddy fields, located in Tamil Nadu, India.

  18. Self-Energy Correction to Momentum-Density Distribution of Positron-Electron Pairs

    NASA Astrophysics Data System (ADS)

    Tang, Z.; Nagai, Y.; Inoue, K.; Toyama, T.; Chiba, T.; Saito, M.; Hasegawa, M.

    2005-03-01

    Positron two-dimensional angular correlation of annihilation radiation (2D ACAR), i.e., the 2D projection of the electron momentum densities sampled by positron, in Si is employed to verify the prediction of the density functional theory within the local-density approximation (LDA). Carefully conducted test shows that the LDA introduces small but definite discrepancies to the 2D-ACAR anisotropies. Self-energy calculation using the GW method indicates that density-fluctuation contributes anisotropic momentum-density correction and thus improves the agreement between theory and experiment. These results provide valuable annotations to the arguments concerning the accuracy and validity of the LDA and GW schemes.

  19. The Self Actualized Reader.

    ERIC Educational Resources Information Center

    Marino, Michael; Moylan, Mary Elizabeth

    A study examined the commonalities that "voracious" readers share, and how their experiences can guide parents, teachers, and librarians in assisting children to become self-actualized readers. Subjects, 25 adults ranging in age from 20 to 67 years, completed a questionnaire concerning their reading histories and habits. Respondents varied in…

  20. An x-ray backlit Talbot-Lau deflectometer for high-energy-density electron density diagnostics

    NASA Astrophysics Data System (ADS)

    Valdivia, M. P.; Stutman, D.; Stoeckl, C.; Theobald, W.; Mileham, C.; Begishev, I. A.; Bromage, J.; Regan, S. P.

    2016-02-01

    X-ray phase-contrast techniques can measure electron density gradients in high-energy-density plasmas through refraction induced phase shifts. An 8 keV Talbot-Lau interferometer consisting of free standing ultrathin gratings was deployed at an ultra-short, high-intensity laser system using K-shell emission from a 1-30 J, 8 ps laser pulse focused on thin Cu foil targets. Grating survival was demonstrated for 30 J, 8 ps laser pulses. The first x-ray deflectometry images obtained under laser backlighting showed up to 25% image contrast and thus enabled detection of electron areal density gradients with a maximum value of 8.1 ± 0.5 × 1023 cm-3 in a low-Z millimeter sized sample. An electron density profile was obtained from refraction measurements with an error of <8%. The 50 ± 15 μm spatial resolution achieved across the full field of view was found to be limited by the x-ray source-size, similar to conventional radiography.

  1. An x-ray backlit Talbot-Lau deflectometer for high-energy-density electron density diagnostics

    DOE PAGESBeta

    Valdivia, M. P.; Stutman, D.; Stoeckl, C.; Theobald, W.; Mileham, C.; Begishev, I. A.; Bromage, J.; Regan, S. P.

    2016-02-10

    X-ray phase-contrast techniques can measure electron density gradients in high-energy-density plasmas through refraction induced phase shifts. An 8 keV Talbot-Lau interferometer consisting of free standing ultrathin gratings was deployed at an ultra-short, high-intensity laser system using K-shell emission from a 1-30 J, 8 ps laser pulse focused on thin Cu foil targets. Grating survival was demonstrated for 30 J, 8 ps laser pulses. The first x-ray deflectometry images obtained under laser backlighting showed up to 25% image contrast and thus enabled detection of electron areal density gradients with a maximum value of 8.1 ± 0.5 × 1023 cm₋3 in amore » low-Z millimeter sized sample. An electron density profile was obtained from refraction measurements with an error of <8%. We found the 50 ± 15 μm spatial resolution achieved across the full field of view was limited by the x-ray source-size, similar to conventional radiography.« less

  2. An x-ray backlit Talbot-Lau deflectometer for high-energy-density electron density diagnostics.

    PubMed

    Valdivia, M P; Stutman, D; Stoeckl, C; Theobald, W; Mileham, C; Begishev, I A; Bromage, J; Regan, S P

    2016-02-01

    X-ray phase-contrast techniques can measure electron density gradients in high-energy-density plasmas through refraction induced phase shifts. An 8 keV Talbot-Lau interferometer consisting of free standing ultrathin gratings was deployed at an ultra-short, high-intensity laser system using K-shell emission from a 1-30 J, 8 ps laser pulse focused on thin Cu foil targets. Grating survival was demonstrated for 30 J, 8 ps laser pulses. The first x-ray deflectometry images obtained under laser backlighting showed up to 25% image contrast and thus enabled detection of electron areal density gradients with a maximum value of 8.1 ± 0.5 × 10(23) cm(-3) in a low-Z millimeter sized sample. An electron density profile was obtained from refraction measurements with an error of <8%. The 50 ± 15 μm spatial resolution achieved across the full field of view was found to be limited by the x-ray source-size, similar to conventional radiography. PMID:26931847

  3. Ambipolar zinc-polyiodide electrolyte for a high-energy density aqueous redox flow battery

    SciTech Connect

    Li, Bin; Nie, Zimin; Vijayakumar, M.; Li, Guosheng; Liu, Jun; Sprenkle, Vincent L.; Wang, Wei

    2015-02-24

    Large-scale energy storage systems are crucial for substantial deployment of renewable energy sources. Energy storage systems with high energy density, high safety, and low cost and environmental friendliness are desired. To overcome the major limitations of the current aqueous redox flow battery systems, namely lower energy density (~25 Wh L-1) and presence of strong acids and/or other hazardous, a high energy density aqueous zinc/polyiodide flow battery (ZIB) is designed with near neutral ZnI2 solutions as catholytes. The energy density of ZIB could reach 322 Wh L-1 at the solubility limit of ZnI2 in water (~7 M). We demonstrate charge and discharge energy densities of 245.9 Wh/L and 166.7 Wh L-1 with ZnI2 electrolyte at 5.0 M, respectively. The addition of ethanol (EtOH) in ZnI2 electrolyte can effectively mitigate the growth of zinc dendrite at the anode and improve the stability of catholytes with wider temperature window (-20 to 50°C), which enable ZIB system to be a promising alternative as a high-energy and high- safety stationary energy storage system.

  4. Ambipolar zinc-polyiodide electrolyte for a high-energy density aqueous redox flow battery

    DOE PAGESBeta

    Li, Bin; Nie, Zimin; Vijayakumar, M.; Li, Guosheng; Liu, Jun; Sprenkle, Vincent L.; Wang, Wei

    2015-02-24

    Large-scale energy storage systems are crucial for substantial deployment of renewable energy sources. Energy storage systems with high energy density, high safety, and low cost and environmental friendliness are desired. To overcome the major limitations of the current aqueous redox flow battery systems, namely lower energy density (~25 Wh L-1) and presence of strong acids and/or other hazardous, a high energy density aqueous zinc/polyiodide flow battery (ZIB) is designed with near neutral ZnI2 solutions as catholytes. The energy density of ZIB could reach 322 Wh L-1 at the solubility limit of ZnI2 in water (~7 M). We demonstrate charge andmore » discharge energy densities of 245.9 Wh/L and 166.7 Wh L-1 with ZnI2 electrolyte at 5.0 M, respectively. The addition of ethanol (EtOH) in ZnI2 electrolyte can effectively mitigate the growth of zinc dendrite at the anode and improve the stability of catholytes with wider temperature window (-20 to 50°C), which enable ZIB system to be a promising alternative as a high-energy and high- safety stationary energy storage system.« less

  5. Ambipolar zinc-polyiodide electrolyte for a high-energy density aqueous redox flow battery

    SciTech Connect

    Li, Bin; Nie, Zimin; Vijayakumar, M.; Li, Guosheng; Liu, Jun; Sprenkle, Vincent L.; Wang, Wei

    2015-02-24

    Large-scale energy storage systems are crucial for substantial deployment of renewable energy sources. Energy storage systems with high energy density, high safety, and low cost and environmental friendliness are desired. To overcome the major limitations of the current aqueous redox flow battery systems, namely lower energy density (~25 Wh L-1) and presence of strong acids and/or other hazardous, a high energy density aqueous zinc/polyiodide flow battery (ZIB) is designed with near neutral ZnI2 solutions as catholytes. The energy density of ZIB could reach 322 Wh L-1 at the solubility limit of ZnI2 in water (~7 M). We demonstrate charge and discharge energy densities of 245.9 Wh/L and 166.7 Wh L-1 with ZnI2 electrolyte at 5.0 M, respectively. The addition of ethanol (EtOH) in ZnI2 electrolyte can effectively mitigate the growth of zinc dendrite at the anode and improve the stability of catholytes with wider temperature window (-20 to 50°C), which enable ZIB system to be a promising alternative as a high-energy and high- safety stationary energy storage system.

  6. Microphysical derivation of the Canham–Helfrich free-energy density

    PubMed Central

    Seguin, Brian; Fried, Eliot

    2013-01-01

    The Canham–Helfrich free-energy density for a lipid bilayer has drawn considerable attention. Aside from the mean and Gaussian curvatures, this free-energy density involves a spontaneous mean-curvature that encompasses information regarding the preferred, natural shape of the lipid bilayer. We use a straightforward microphysical argument to derive the Canham–Helfrich free-energy density. Our derivation (i) provides a justification for the common assertion that spontaneous curvature originates primarily from asymmetry between the leaflets comprising a bilayer and (ii) furnishes expressions for the splay and saddle-splay moduli in terms of derivatives of the underlying potential. PMID:23389779

  7. Level densities of iron isotopes and low-energy enhancement of {gamma}-strength function

    SciTech Connect

    Voinov, A. V.; Grimes, S. M.; Brune, C. R.; Hornish, M. J.; Massey, T. N.; Agvaanluvsan, U.; Algin, E.; Belgya, T.; Guttormsen, M.; Rekstad, J.; Siem, S.; Mitchell, G. E.; Schiller, A.

    2006-03-13

    The neutron spectrum from the 55Mn(d, n)56Fe reaction has been measured at Ed = 7 MeV. The level density of 56Fe obtained from neutron evaporation spectrum has been compared to the level density obtained from Oslo-type 57Fe(3He, {alpha}{gamma})56Fe experiment. The good agreement supports the recent results including the low-energy enhancement in the {gamma}-strength function for iron isotopes. The new level density function allowed us to investigate an excitation energy dependence of this enhancement, which is shown to increase with increasing excitation energy.

  8. Dietary Energy Density Is Positively Associated with Risk of Pancreatic Cancer in Urban Shanghai Chinese12

    PubMed Central

    Wang, Jing; Zhang, Wei; Sun, Lu; Yu, Herbert; Ni, Quan-Xing; Risch, Harvey A.; Gao, Yu-Tang

    2013-01-01

    Regular consumption of energy-dense foods predisposes to obesity and type 2 diabetes, both of which are suggested risk factors for pancreatic cancer. The aim of this study was to investigate whether energy density of foods is an independent risk factor for pancreatic cancer. In this population-based case-control study in urban Shanghai, 908 patients with pancreatic cancer and 1067 normal controls, aged 35–79 y, were recruited. The energy density for overall diet was calculated from food-frequency questionnaire data. Energy density (adjusted for age, sex, and total energy intake) was significantly higher in cases (6.08 ± 0.04 kJ/g) than in controls (5.91 ± 0.04 kJ/g) (P = 0.003). Energy density was positively associated with pancreatic cancer risk (OR: 1.16 per unit increase; 95% CI: 1.07, 1.27; P < 0.001). In adjusted analysis, the risk of pancreatic cancer was 72% greater (OR: 1.72; 95% CI: 1.25, 2.35; P = 0.001) in the highest quintile of energy density compared with the lowest quintile. In this case-control study, dietary energy density is positively associated with risk of pancreatic cancer. This association should be further investigated in prospective studies. PMID:23902959

  9. Effects of portion size and energy density on young children's intake at a meal

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Large portions of energy-dense foods are one feature of obesity-promoting dietary environments. Entrée portion size has been shown to influence energy intake at meals by young children. The role of energy density (ED) in children’s response to portion size, however, is unknown. We aimed to test th...

  10. Influencing and modifying children's energy intake: the role of portion size and energy density.

    PubMed

    Pourshahidi, L Kirsty; Kerr, Maeve A; McCaffrey, Tracy A; Livingstone, M Barbara E

    2014-08-01

    Childhood obesity is of concern worldwide. The portion size (PS) and energy density (ED) of food are two major determinants of children's energy intake (EI). Trends towards increasing PS are most apparent and best documented in the USA, where PS of numerous food products have increased in the marketplace over the past three decades, particularly high-energy dense foods. Analyses of population-level dietary surveys have confirmed this trend in children for both in- and out-of-home eating, and a plethora of observational evidence positively associates PS, ED and adiposity in children. A limited number of intervention studies provide clear evidence that children, even as young as 2 years, respond acutely to increasing PS, with some studies also demonstrating the additive effects of increased ED in promoting excessive EI. However, most of the evidence is based on children aged 3-6 years and there is a paucity of data in older children and adolescents. It is unclear whether decreasing PS can have the opposite effect on children's EI but recent acute studies have demonstrated that the incorporation of lower energy dense foods, such as fruit and vegetables, into children's meals down-regulates EI. Although a direct causal link between PS and obesity remains to be established, the regular consumption of larger PS of energy dense foods do favour obesity-promoting eating behaviours in children. Further research is required to establish the most feasible and effective interventions and policies to counteract the deleterious impact of PS and ED on children's EI. PMID:24886909

  11. Achieving tunable sensitivity in composite high-energy density materials

    NASA Astrophysics Data System (ADS)

    Rashkeev, Sergey; Tsyshevsky, Roman; Kuklja, Maija

    2015-06-01

    Laser irradiation provides a unique opportunity for selective, predictive, and controlled initiation of energetic materials. We propose a consistent micro-scale mechanism of photoexcitation at the interface, formed by a molecular energetic material and a metal oxide. A specific PETN-MgO model composite is used to illustrate and explain seemingly puzzling experiments on selective laser initiation of energetic materials, which reported that the presence of metal oxide additives triggered the photoinitiation by an unusually low energy. We suggest that PETN photodecomposition is catalyzed by oxygen vacancies (F0 centers) at the MgO surface. The proposed model suggests ways to tune sensitivity of energetic molecular materials to photoinitiation. Our quantum-chemical calculations suggest that the structural defects (e.g., oxygen vacancies) strongly interact with the molecular material (e.g., adsorbed energetic molecules) by inducing a charge transfer at the interface and hence play an imperative role in governing both energy absorption and energy release in the system. Our approach and conclusions provide a solid basis for novel design of energetic interfaces with desired properties and offers a new perspective in the field of explosive materials and devices.

  12. The National Ignition Facility - Applications for Inertial Fusion Energy and High Energy Density Science

    SciTech Connect

    Campbell, E.M.; Hogan, W.J.

    1999-08-12

    Over the past several decades, significant and steady progress has been made in the development of fusion energy and its associated technology and in the understanding of the physics of high-temperature plasmas. While the demonstration of net fusion energy (fusion energy production exceeding that required to heat and confine the plasma) remains a task for the next millennia and while challenges remain, this progress has significantly increased confidence that the ultimate goal of societally acceptable (e.g. cost, safety, environmental considerations including waste disposal) central power production can be achieved. This progress has been shared by the two principal approaches to controlled thermonuclear fusion--magnetic confinement (MFE) and inertial confinement (ICF). ICF, the focus of this article, is complementary and symbiotic to MFE. As shown, ICF invokes spherical implosion of the fuel to achieve high density, pressures, and temperatures, inertially confining the plasma for times sufficient long (t {approx} 10{sup -10} sec) that {approx} 30% of the fuel undergoes thermonuclear fusion.

  13. Determination of energy density threshold for laser ablation of bacteria. An in vitro study.

    PubMed

    Coffelt, D W; Cobb, C M; MacNeill, S; Rapley, J W; Killoy, W J

    1997-01-01

    The Nd:YAG and CO2 lasers have been shown to be bactericidal at relative low energy densities. However, at energy densities exceeding 120 J/cm2 (CO2) and 200 J/cm2 (Nd:YAG), laser irradiation also causes irreparable root surface damage. The purpose of this study was to determine, in vitro, the energy density threshold at which microbial ablation could be achieved while inflicting the least amount of damage to the root surfaces of human teeth. Pairs of Escherichia coli colonies cultured on broth agar were treated with a CO2 laser using a pulsed waveform at approximate energy densities ranging from 3 to 110 J/cm2. One of each colony-pair was then examined by scanning electron microscopy (SEM) and the other subcultured for viable microbes. Roots of extracted teeth were lightly scaled and treated by CO2 laser, again with pulsed beam using approximate energy densities of 3 to 110 J/cm2: and examined by SEM. Regardless of the level of energy density, residual bacteria could be subcultured from all laser treated microbial colonies. The inability of the laser to completely obliterate microbial colonies was likely due to: depth of energy penetration, difficulty in precisely overlapping beam focal spots, irregular beam profile, and presence of microbes at the periphery of the beam focal spot. The threshold energy density for bacterial obliteration was determined to be 11 J/cm2 and that for root damage was 41 J/cm2. Root damage was evident by charring, crater formation, melt-down and resolidification surface mineral, and increasing surface porosity. The results of this in vitro study indicate that when used at an energy density between 11 and 41 J/cm2 the CO2 laser may destroy microbial colonies without inflicting undue damage to the tooth root surface. PMID:9049791

  14. Dietary energy density was associated with diet quality in Brazilian adults and older adults.

    PubMed

    Mendes, Aline; Pereira, Jaqueline Lopes; Fisberg, Regina Mara; Marchioni, Dirce Maria Lobo

    2016-02-01

    Cross-sectional and longitudinal studies present association of low dietary energy density with higher intake of vitamins, minerals and dietary fiber, lower intake of fat, and better balance of macronutrients. The objective of this study was to verify the relationship between dietary energy density and diet quality measured by an index of diet quality. This study used data from 496 adults and 445 older adults of cross-sectional population-based survey from São Paulo conducted in 2008-2009, Brazil. Dietary intake data was assessed by two 24-h dietary recalls. Dietary energy density values were calculated based on foods only method. Dietary energy density and revised Brazilian Health Eating Index and its components, were estimated by usual intake using Multiple Source Method. The relationship between dietary energy density and the total revised Brazilian Health Eating Index and its components were assessed by Gaussian family log-link model for each age group. The analyses showed an inverse association between dietary energy density and total revised Brazilian Health Eating Index in adults (T2:β = 0.96, p < 0.001; T2:β = 0.86, p < 0.001) and older adults (T2:β = 0.96, p < 0.001; T2:β = 0.90, p < 0.001), and an inverse association between dietary energy density and nine of twelve revised Brazilian Health Eating Index components in adult and/or older adults groups. Dietary energy density was associated with diet quality in Brazilian adults and older adults regardless of sex, per capita household income, body mass index, physical activity level, current smoking habits status, alcohol beverage drinking status and usual energy intake (kilocalories) from beverages. PMID:26626824

  15. Energy Confinement of High-Density Pellet-Fueled Plasmas in the Alcator C Tokamak

    NASA Astrophysics Data System (ADS)

    Greenwald, M.; Gwinn, D.; Milora, S.; Parker, J.; Parker, R.; Wolfe, S.; Besen, M.; Camacho, F.; Fairfax, S.; Fiore, C.; Foord, M.; Gandy, R.; Gomez, C.; Granetz, R.; Labombard, B.; Lipschultz, B.; Lloyd, B.; Marmar, E.; McCool, S.; Pappas, D.; Petrasso, R.; Pribyl, P.; Rice, J.; Schuresko, D.; Takase, Y.; Terry, J.; Watterson, R.

    1984-07-01

    A series of pellet-fueling experiments has been carried out on the Alcator C tokamak. High-speed hydrogen pellets penetrate to within a few centimeters of the magnetic axis, raise the plasma density, and produce peaked density profiles. Energy confinement is observed to increase over similar discharges fueled only by gas puffing. In this manner record values of electron density, plasma pressure, and Lawson number (n τ) have been achieved.

  16. The energy balance relation for weak solutions of the density-dependent Navier-Stokes equations

    NASA Astrophysics Data System (ADS)

    Leslie, T. M.; Shvydkoy, R.

    2016-09-01

    We consider the incompressible inhomogeneous Navier-Stokes equations with constant viscosity coefficient and density which is bounded and bounded away from zero. We show that the energy balance relation for this system holds for weak solutions if the velocity, density, and pressure belong to a range of Besov spaces of smoothness 1/3. A density-dependent version of the classical Kármán-Howarth-Monin relation is derived.

  17. Quantification of breast density with dual energy mammography: An experimental feasibility study

    SciTech Connect

    Ducote, Justin L.; Molloi, Sabee

    2010-02-15

    Purpose: Breast density, the percentage of glandular breast tissue, has been shown to be a strong indicator of breast cancer risk. A quantitative method to measure breast density with dual energy mammography was investigated using physical phantoms. Methods: The dual energy mammography system used a tungsten anode x-ray tube with a 50 {mu}m rhodium beam filter for low energy images and a 300 {mu}m copper beam filter for high energy images. Glandular and adipose equivalent phantoms of uniform thickness were used to calibrate a dual energy basis decomposition algorithm. Four different phantom studies were used to evaluate the technique. The first study consisted of phantoms with thicknesses of 2.5-8.5 cm in 0.5 cm steps with variable densities centered at a mean of 28%. The second study consisted of phantoms at a fixed thickness of 4.0 cm, which ranged in densities from 0% to 100% in increments of 12.5%. The third study consisted of 4.0 cm thick phantoms at densities of 25%, 50% and 75% each imaged at three areal sizes, approximately 62.5, 125, and 250 cm{sup 2}, in order to assess the effect of breast size on density measurement. The fourth study consisted of step phantoms designed to more closely mimic the shape of a female breast with maximal thicknesses from 3.0 to 7.0 cm at a fixed density of 50%. All images were corrected for x-ray scatter. Results: The RMS errors in breast density measurements were 0.44% for the variable thickness phantoms, 0.64% for the variable density phantoms, 2.87% for the phantoms of different areal sizes, and 4.63% for step phantoms designed to closely resemble the shape of a breast. Conclusions: The results of the phantom studies indicate that dual energy mammography can be used to measure breast density with an RMS error of approximately 5%.

  18. First principles prediction of an insensitive high energy density material.

    PubMed

    Hirshberg, Barak; Denekamp, Chagit

    2013-10-28

    A new high performance yet insensitive explosive is proposed, based on an extensive computational study of tris(tetrazolyl)amine in the solid state and in the gas phase. The calculations for the solid state employ the PBE density functional with empirical dispersion correction while the gas phase calculations use the higher level of B3LYP and MP2. Two stable crystalline structures of tris(tertrazolyl)amine were located belonging to P1 and P21 space groups. The crystal structures obtained reveal that solid tris(tertrazolyl)amine is organized in layers with a very small interlayer spacing, due to π stacking, as well as significant inter and intra-molecular hydrogen bonding. Application of these results to the calculation of the detonation velocity and pressure indicate high performance for both phases, especially the P21 phase. At the same time the small value found for the interlayer spacing and the significant hydrogen bonding suggest relatively high stability. These results point to a promising new explosive material with a balance between high performance and insensitivity. PMID:24042364

  19. Laser Driven Radiative Shocks in High Energy Density

    NASA Astrophysics Data System (ADS)

    Manka, C.; Lunsford, R.; Nikitin, S.; Laming, M.; Zabatakis, D.; Grun, J.

    2008-03-01

    The long time over which oscillations associated with radiative shocks within the interstellar medium occur makes direct observation of these instabilities highly problematic. A velocity dependant cooling instability is thought to cause fluctuations in the propagation velocity of such shocks. An experiment at NRL investigates and perhaps validates the applicability of present analytic models to various multidimensional radiative shock instabilities. The PHAROS laser at NRL is used to create the relevant shock front by ablative acceleration of an aluminized Mylar foil that covers a small gas filled tunnel in a PMMA block. As this shock propagates along the tunnel, a secondary shock is launched into the walls of the tunnel and the progress of this shock into the PMMA block preserves a continuous record of the primary shock's velocity as it travels the length of the tunnel. The density gradient associated with the shock in the PMMA is recorded using dark field shadowgraphy on a SIM-8 multi-channel high speed framing camera. The tunnel shock velocity is determined from the shape of the shock launched into the PMMA block for any time prior to the instant at which the image frame was taken, providing documentation of any oscillations in the velocity of the shock.

  20. Plasma guns for controlled fusion at megagauss energy-densities

    SciTech Connect

    Turchi, Peter J; Roderick, Norman F; Degnan, James H; Frese, Michael H

    2008-01-01

    Electron cyclotron current drive (ECCD) at a low power level has been used on Tore Supra to induce local perturbations of the current density profile. Regimes with strong MHD activity have been analysed, and compared with similar stable discharges, in order to investigate the possible causes of their instability and relate the evolution of the discharge to the localization of EC power deposition. Both co- and counter-current drive pulses have been applied to dominantly or fully non-inductive discharges, sustained by a lower hybrid current drive. Detailed reconstructions by current diffusion calculations have been performed and the error bars evaluated. This method has proved valuable for shedding light on the complex interplay between the evolutions of temperature and safety factor profiles in steady-state tokamak plasmas. The crucial role of the dynamic evolution of rational surfaces has been identified. Moreover, we demonstrate that the operational domain in which ECCD can be employed must cope with the overall current profile characteristics, in particular the position where the safety factor has a minimum.

  1. High energy density capacitors for power electronic applications using nano-structure multilayer technology

    SciTech Connect

    Barbee, T.W. Jr.; Johnson, G.W.

    1995-09-01

    Power electronics applications are currently limited by capacitor size and performance. Only incremental improvements are anticipated in existing capacitor technologies, while significant performance advances are required in energy density and overall performance to meet the technical needs of the applications which are important for U.S. economic competitiveness. One application, the Power Electronic Building Block (PEBB), promises a second electronics revolution in power electronic design. High energy density capacitors with excellent electrical thermal and mechanical performance represent an enabling technology in the PEBB concept. We propose a continuing program to research and develop LLNL`s nano-structure multilayer technologies for making high voltage, high energy density capacitors. Our controlled deposition techniques are capable of synthesizing extraordinarily smooth sub-micron thick layers of dielectric and conductor materials. We have demonstrated that, with this technology, high voltage capacitors with an order of magnitude improvement in energy density are achievable.

  2. Actual evapotranspiration (water use) assessment of the Colorado River Basin at the Landsat resolution using the operational simplified surface energy balance model

    USGS Publications Warehouse

    Singh, Ramesh K.; Senay, Gabriel B.; Velpuri, Naga Manohar; Bohms, Stefanie; Russell L, Scott; Verdin, James P.

    2014-01-01

    Accurately estimating consumptive water use in the Colorado River Basin (CRB) is important for assessing and managing limited water resources in the basin. Increasing water demand from various sectors may threaten long-term sustainability of the water supply in the arid southwestern United States. We have developed a first-ever basin-wide actual evapotranspiration (ETa) map of the CRB at the Landsat scale for water use assessment at the field level. We used the operational Simplified Surface Energy Balance (SSEBop) model for estimating ETa using 328 cloud-free Landsat images acquired during 2010. Our results show that cropland had the highest ETa among all land cover classes except for water. Validation using eddy covariance measured ETa showed that the SSEBop model nicely captured the variability in annual ETa with an overall R2 of 0.78 and a mean bias error of about 10%. Comparison with water balance-based ETa showed good agreement (R2 = 0.85) at the sub-basin level. Though there was good correlation (R2 = 0.79) between Moderate Resolution Imaging Spectroradiometer (MODIS)-based ETa (1 km spatial resolution) and Landsat-based ETa (30 m spatial resolution), the spatial distribution of MODIS-based ETa was not suitable for water use assessment at the field level. In contrast, Landsat-based ETa has good potential to be used at the field level for water management. With further validation using multiple years and sites, our methodology can be applied for regular production of ETa maps of larger areas such as the conterminous United States.

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

    SciTech Connect

    2007-08-01

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

  4. METHODOLOGICAL NOTES: Energy density calculations for ball-lightning-like luminous silicon balls

    NASA Astrophysics Data System (ADS)

    Paiva, Gerson S.; Ferreira, Joacy V.; Bastos, Cristiano C.; dos Santos, Marcus V.; Pavão, Antonio C.

    2010-05-01

    The energy density of a luminous silicon ball [Phys. Rev. Lett. 98 048501 (2007)] is calculated for a model with a metal core surrounded by an atmosphere of silicon oxides. Experimental data combined with the molecular orbital calculations of the oxidation enthalpy lead to a mean energy density of 3.9 MJ m-3, which is within the range of estimates from other ball lightning models. This result provides good evidence to support the silicon-based model.

  5. Equation of state for tungsten over a wide range of densities and internal energies

    NASA Astrophysics Data System (ADS)

    Khishchenko, K. V.

    2015-11-01

    A caloric model, which describes the pressure-density-internal-energy relationship in a broad region of condensed-phase states, is applied for tungsten. As distinct from previously known caloric equations of state for this material, a new form of the cold-compression curve at T = 0 K is used. Thermodynamic characteristics along the cold curve and shock Hugoniots are calculated for the metal and compared with some theoretical results and experimental data available at high energy densities.

  6. Excitation energies of molecules within time-independent density functional theory

    SciTech Connect

    Hemanadhan, M. Harbola, Manoj K.

    2014-04-24

    Recently proposed exchange energy functional for excited-states is tested for obtaining excitation energies of diatomic molecules. The functional is the ground-state counterpart of the local-density approximation, the modified local spin density (MLSD). The MLSD functional is tested for the N{sub 2} and CO diatomic molecules. The excitation energy obtained with the MLSD functional for the N{sub 2} molecule is in close vicinity to that obtained from the exact exchange orbital functional, Krieger, Li and Iafrate (KLI). For the CO molecule, the departure in excitation energy is observed and is due to the overcorrection of self-interaction.

  7. Effects of the density dependence of the nuclear symmetry energy on the properties of superheavy nuclei

    SciTech Connect

    Jiang Weizhou

    2010-04-15

    Effects of the density dependence of the nuclear symmetry energy on ground-state properties of superheavy nuclei are studied in the relativistic mean-field theory. It is found that the softening of the symmetry energy plays an important role in the empirical shift [Phys. Rev. C 67, 024309 (2003)] of spherical orbitals in superheavy nuclei. The calculation based on the relativistic mean-field models NL3 and FSUGold supports the double shell closure in {sup 292}120 with the softening of the symmetry energy. In addition, the significant effect of the density dependence of the symmetry energy on the neutron skin thickness in superheavy nuclei is investigated.

  8. Dietary energy density and body weight in adults and children: a systematic review.

    PubMed

    Pérez-Escamilla, Rafael; Obbagy, Julie E; Altman, Jean M; Essery, Eve V; McGrane, Mary M; Wong, Yat Ping; Spahn, Joanne M; Williams, Christine L

    2012-05-01

    Energy density is a relatively new concept that has been identified as an important factor in body weight control in adults and in children and adolescents. The Dietary Guidelines for Americans 2010 encourages consumption of an eating pattern low in energy density to manage body weight. This article describes the systematic evidence-based review conducted by the 2010 Dietary Guidelines Advisory Committee (DGAC), with support from the US Department of Agriculture's Nutrition Evidence Library, which resulted in this recommendation. An update to the committee's review was prepared for this article. PubMed was searched for English-language publications from January 1980 to May 2011. The literature review included 17 studies (seven randomized controlled trials, one nonrandomized controlled trial, and nine cohort studies) in adults and six cohort studies in children and adolescents. Based on this evidence, the 2010 Dietary Guidelines Advisory Committee concluded that strong and consistent evidence in adults indicates that dietary patterns relatively low in energy density improve weight loss and weight maintenance. In addition, the committee concluded that there was moderately strong evidence from methodologically rigorous longitudinal cohort studies in children and adolescents to suggest that there is a positive association between dietary energy density and increased adiposity. This review supports a relationship between energy density and body weight in adults and in children and adolescents such that consuming diets lower in energy density may be an effective strategy for managing body weight. PMID:22480489

  9. Densities and energies of nuclei in dilute matter at zero temperature

    NASA Astrophysics Data System (ADS)

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

    2013-10-01

    We explore the properties of medium-mass and heavy nuclear clusters embedded in a gas of nucleons with the help of Skyrme-Hartree-Fock microscopic calculations at zero temperature. Two alternative representations of clusters are introduced, namely coordinate-space and energy-space clusters. We parametrize 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 on that 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 equation of state and related perspectives. Our study provides a simple but microscopically motivated modeling of the energetics of clusterized matter at subsaturation densities for applications of astrophysical interest.

  10. Spectroscopic properties of nuclear skyrme energy density functionals.

    PubMed

    Tarpanov, D; Dobaczewski, J; Toivanen, J; Carlsson, B G

    2014-12-19

    We address the question of how to improve the agreement between theoretical nuclear single-particle energies (SPEs) and observations. Empirically, in doubly magic nuclei, the SPEs can be deduced from spectroscopic properties of odd nuclei that have one more or one less neutron or proton. Theoretically, bare SPEs, before being confronted with observations, must be corrected for the effects of the particle vibration coupling (PVC). In the present work, we determine the PVC corrections in a fully self-consistent way. Then, we adjust the SPEs, with PVC corrections included, to empirical data. In this way, the agreement with observations, on average, improves; nevertheless, large discrepancies still remain. We conclude that the main source of disagreement is still in the underlying mean fields, and not in including or neglecting the PVC corrections. PMID:25554877

  11. Collaborative Comparison of High-Energy-Density Physics Codes

    NASA Astrophysics Data System (ADS)

    Fatenejad, M.; Fryer, C.; Fryxell, B.; Lamb, D.; Myra, E.; Wohlbier, J.

    2011-10-01

    We will describe a collaborative effort involving the Flash Center for Computational Science, The Center for Radiative Shock Hydrodynamics (CRASH), LANL, and LLNL to compare several sophisticated radiation-hydrodynamics codes on a variety of HEDP test problems and experiments. Currently we are comparing efforts to simulate ongoing radiative shock experiments being conducted by CRASH at the OMEGA laser facility that are relevant to a wide range of astrophysical problems. The experiments drive a collapsed planar radiative shock through a Xenon-filled shock tube. Attempts to simulate these experiments have uncovered various challenges to obtaining agreement with experimental results. We will present the results of code-to-code comparisons that have enabled us to understand the impact of differences in numerical methods, physical approximations, microphysical parameters, etc. This work was supported in part by the US Department of Energy.

  12. Density functional theory screening of gas-treatment strategies for stabilization of high energy-density lithium metal anodes

    NASA Astrophysics Data System (ADS)

    Koch, Stephan L.; Morgan, Benjamin J.; Passerini, Stefano; Teobaldi, Gilberto

    2015-11-01

    To explore the potential of molecular gas treatment of freshly cut lithium foils in non-electrolyte-based passivation of high-energy-density Li anodes, density functional theory (DFT) has been used to study the decomposition of molecular gases on metallic lithium surfaces. By combining DFT geometry optimization and Molecular Dynamics, the effects of atmospheric (N2, O2, CO2) and hazardous (F2, SO2) gas decomposition on Li(bcc) (100), (110), and (111) surfaces on relative surface energies, work functions, and emerging electronic and elastic properties are investigated. The simulations suggest that exposure to different molecular gases can be used to induce and control reconstructions of the metal Li surface and substantial changes (up to over 1 eV) in the work function of the passivated system. Contrary to the other considered gases, which form metallic adlayers, SO2 treatment emerges as the most effective in creating an insulating passivation layer for dosages ≤1 mono-layer. The substantial Li → adsorbate charge transfer and adlayer relaxation produce marked elastic stiffening of the interface, with the smallest change shown by nitrogen-treated adlayers.

  13. High-energy density nonaqueous all redox flow lithium battery enabled with a polymeric membrane.

    PubMed

    Jia, Chuankun; Pan, Feng; Zhu, Yun Guang; Huang, Qizhao; Lu, Li; Wang, Qing

    2015-11-01

    Redox flow batteries (RFBs) are considered one of the most promising large-scale energy storage technologies. However, conventional RFBs suffer from low energy density due to the low solubility of the active materials in electrolyte. On the basis of the redox targeting reactions of battery materials, the redox flow lithium battery (RFLB) demonstrated in this report presents a disruptive approach to drastically enhancing the energy density of flow batteries. With LiFePO4 and TiO2 as the cathodic and anodic Li storage materials, respectively, the tank energy density of RFLB could reach ~500 watt-hours per liter (50% porosity), which is 10 times higher than that of a vanadium redox flow battery. The cell exhibits good electrochemical performance under a prolonged cycling test. Our prototype RFLB full cell paves the way toward the development of a new generation of flow batteries for large-scale energy storage. PMID:26702440

  14. High–energy density nonaqueous all redox flow lithium battery enabled with a polymeric membrane

    PubMed Central

    Jia, Chuankun; Pan, Feng; Zhu, Yun Guang; Huang, Qizhao; Lu, Li; Wang, Qing

    2015-01-01

    Redox flow batteries (RFBs) are considered one of the most promising large-scale energy storage technologies. However, conventional RFBs suffer from low energy density due to the low solubility of the active materials in electrolyte. On the basis of the redox targeting reactions of battery materials, the redox flow lithium battery (RFLB) demonstrated in this report presents a disruptive approach to drastically enhancing the energy density of flow batteries. With LiFePO4 and TiO2 as the cathodic and anodic Li storage materials, respectively, the tank energy density of RFLB could reach ~500 watt-hours per liter (50% porosity), which is 10 times higher than that of a vanadium redox flow battery. The cell exhibits good electrochemical performance under a prolonged cycling test. Our prototype RFLB full cell paves the way toward the development of a new generation of flow batteries for large-scale energy storage. PMID:26702440

  15. Energy density inhomogeneities in charged radiating stars with generalized CDTT model

    NASA Astrophysics Data System (ADS)

    Sharif, M.; Yousaf, Z.

    2014-12-01

    In this paper, we analyze the role of electromagnetic field and generalized Carrol-Duvvuri-Trodden-Turner (CDTT) model on the existence of homogeneous energy density. For this purpose, we model spherical star with anisotropic matter distribution dissipating in the mode of heat and radiation density. To develop a relationship between the Weyl tensor and matter parameters, we construct two evolution equations. We explore inhomogeneity parameters for particular cases of non-dissipative and dissipative matter distributions. It is concluded that in addition to other fluid variables higher order f( R) corrections, relaxation processes and electromagnetic field affect the energy density inhomogeneity of spherical stars.

  16. High-Energy Ions from Near-Critical Density Plasmas via Magnetic Vortex Acceleration

    SciTech Connect

    Nakamura, Tatsufumi; Bulanov, Sergei V.; Esirkepov, Timur Zh.; Kando, Masaki

    2010-09-24

    Ultraintense laser pulses propagating in near-critical density plasmas generate magnetic dipole vortex structures. In the region of decreasing plasma density, the vortex expands both in forward and lateral directions. The magnetic field pressure pushes electrons and ions to form a density jump along the vortex axis and induces a longitudinal electric field. This structure moves together with the expanding dipole vortex. The background ions located ahead of the electric field are accelerated to high energies. The energy scaling of ions generated by this magnetic vortex acceleration mechanism is derived and corroborated using particle-in-cell simulations.

  17. The performance of density functional approximations for the structures and relative energies of minimum energy crossing points

    NASA Astrophysics Data System (ADS)

    Abate, Bayileyegn A.; Peralta, Juan E.

    2013-12-01

    The structural parameters and relative energies of the minimum-energy crossing points (MECPs) of eight small molecules are calculated using five different representative density functional theory approximations as well as MP2, MP4, and CCSD(T) as a reference. Compared to high-level wavefunction methods, the main structural features of the MECPs of the systems included in this Letter are reproduced reasonably well by density functional approximations, in agreement with previous works. Our results show that when high-level wavefunction methods are computationally prohibitive, density functional approximations offer a good alternative for locating and characterizing the MECP in spin-forbidden chemical reactions.

  18. Towards a Microscopic Reaction Description Based on Energy Density Functionals

    SciTech Connect

    Nobre, G A; DIetrich, F S; Escher, J E; Thompson, I J; Dupuis, M; Terasaki, J; Engel, J

    2011-09-26

    A microscopic calculation of reaction cross sections for nucleon-nucleus scattering has been performed by explicitly coupling the elastic channel to all particle-hole excitations in the target and one-nucleon pickup channels. The particle-hole states may be regarded as doorway states through which the flux flows to more complicated configurations, and subsequently to long-lived compound nucleus resonances. Target excitations for {sup 40,48}Ca, {sup 58}Ni, {sup 90}Zr and {sup 144}Sm were described in a random-phase framework using a Skyrme functional. Reaction cross sections obtained agree very well with experimental data and predictions of a state-of-the-art fitted optical potential. Couplings between inelastic states were found to be negligible, while the pickup channels contribute significantly. The effect of resonances from higher-order channels was assessed. Elastic angular distributions were also calculated within the same method, achieving good agreement with experimental data. For the first time observed absorptions are completely accounted for by explicit channel coupling, for incident energies between 10 and 70 MeV, with consistent angular distribution results.

  19. Encircling the dark: constraining dark energy via cosmic density in spheres

    NASA Astrophysics Data System (ADS)

    Codis, S.; Pichon, C.; Bernardeau, F.; Uhlemann, C.; Prunet, S.

    2016-05-01

    The recently published analytic probability density function for the mildly non-linear cosmic density field within spherical cells is used to build a simple but accurate maximum likelihood estimate for the redshift evolution of the variance of the density, which, as expected, is shown to have smaller relative error than the sample variance. This estimator provides a competitive probe for the equation of state of dark energy, reaching a few percent accuracy on wp and wa for a Euclid-like survey. The corresponding likelihood function can take into account the configuration of the cells via their relative separations. A code to compute one-cell density probability density functions for arbitrary initial power spectrum, top-hat smoothing and various spherical collapse dynamics is made available online so as to provide straightforward means of testing the effect of alternative dark energy models and initial power-spectra on the low-redshift matter distribution.

  20. Encircling the dark: constraining dark energy via cosmic density in spheres

    NASA Astrophysics Data System (ADS)

    Codis, S.; Pichon, C.; Bernardeau, F.; Uhlemann, C.; Prunet, S.

    2016-08-01

    The recently published analytic probability density function for the mildly non-linear cosmic density field within spherical cells is used to build a simple but accurate maximum likelihood estimate for the redshift evolution of the variance of the density, which, as expected, is shown to have smaller relative error than the sample variance. This estimator provides a competitive probe for the equation of state of dark energy, reaching a few per cent accuracy on wp and wa for a Euclid-like survey. The corresponding likelihood function can take into account the configuration of the cells via their relative separations. A code to compute one-cell-density probability density functions for arbitrary initial power spectrum, top-hat smoothing and various spherical-collapse dynamics is made available online, so as to provide straightforward means of testing the effect of alternative dark energy models and initial power spectra on the low-redshift matter distribution.

  1. High Energy Density Science with Ultrarelativistic Electron Beams

    NASA Astrophysics Data System (ADS)

    Joshi, Chan

    2001-10-01

    An intense, high-energy electron or positron beam can have focused intensities rivaling those of today's most powerful lasers. For example, the 5 ps (FWHM), 50 GeV beam at the Stanford Linear Accelerator Center at 1 kA and focused to a 3 micron rms spot size gives intensities of > 10^20 W/cm^2 at a repetition rate of 10 Hz. Unlike a ps or fs laser pulse, the particle beam can readily bore through several mm of steel due to the rigidity of its flux component. However, the same particle beam can be manipulated quite strongly by a plasma that is a million times less dense than air! This is because of the incredibly strong collective fields induced in the plasma by the Coulomb force of the beam. The collective fields in turn react back onto the beam leading to many clearly-observable phenomena. The beam can be: (1) deflected leading focusing, defocusing, or even steering of the beam; (2) undulated causing the emission of spontaneous betatron x-ray radiation and; (3) accelerated or de-accelerated by the plasma fields. Using the 28.5 GeV electron and positron beams from the SLAC linac we have carried out a series of experiments that demonstrate clearly the above mentioned effects. The results are compared with theoretical predictions and 3D, one-to-one PIC code simulations using the code OSIRIS. These phenomena may have practical application in future technologies including optical elements in particle beam lines, synchrotron light sources, and ultra-high gradient accelerators.

  2. High energy density plasma science with an ultrarelativistic electron beam

    NASA Astrophysics Data System (ADS)

    Joshi, C.; Blue, B.; Clayton, C. E.; Dodd, E.; Huang, C.; Marsh, K. A.; Mori, W. B.; Wang, S.; Hogan, M. J.; O'Connell, C.; Siemann, R.; Watz, D.; Muggli, P.; Katsouleas, T.; Lee, S.

    2002-05-01

    An intense, high-energy electron or positron beam can have focused intensities rivaling those of today's most powerful laser beams. For example, the 5 ps (full-width, half-maximum), 50 GeV beam at the Stanford Linear Accelerator Center (SLAC) at 1 kA and focused to a 3 micron rms spot size gives intensities of >1020 W/cm-2 at a repetition rate of >10 Hz. Unlike a ps or fs laser pulse which interacts with the surface of a solid target, the particle beam can readily tunnel through tens of cm of steel. However, the same particle beam can be manipulated quite effectively by a plasma that is a million times less dense than air! This is because of the incredibly strong collective fields induced in the plasma by the Coulomb force of the beam. The collective fields in turn react back onto the beam leading to many clearly observable phenomena. The beam paraticles can be: (1) Deflected leading to focusing, defocusing, or even steering of the beam; (2) undulated causing the emission of spontaneous betatron x-ray radiation and; (3) accelerated or decelerated by the plasma fields. Using the 28.5 GeV electron beam from the SLAC linac a series of experiments have been carried out that demonstrate clearly many of the above mentioned effects. The results can be compared with theoretical predictions and with two-dimensional and three-dimensional, one-to-one, particle-in-cell code simulations. These phenomena may have practical applications in future technologies including optical elements in particle beam lines, synchrotron light sources, and ultrahigh gradient accelerators.

  3. Constraints on the inner edge of neutron star crusts from relativistic nuclear energy density functionals

    SciTech Connect

    Moustakidis, Ch. C.; Lalazissis, G. A.; Niksic, T.; Vretenar, D.; Ring, P.

    2010-06-15

    The transition density n{sub t} and pressure P{sub t} at the inner edge between the liquid core and the solid crust of a neutron star are analyzed using the thermodynamical method and the framework of relativistic nuclear energy density functionals. Starting from a functional that has been carefully adjusted to experimental binding energies of finite nuclei, and varying the density dependence of the corresponding symmetry energy within the limits determined by isovector properties of finite nuclei, we estimate the constraints on the core-crust transition density and pressure of neutron stars: 0.086 fm{sup -3}<=n{sub t}<0.090 fm{sup -3} and 0.3 MeV fm{sup -3}

  4. A coarse-grain force field for RDX: Density dependent and energy conserving

    NASA Astrophysics Data System (ADS)

    Moore, Joshua D.; Barnes, Brian C.; Izvekov, Sergei; Lísal, Martin; Sellers, Michael S.; Taylor, DeCarlos E.; Brennan, John K.

    2016-03-01

    We describe the development of a density-dependent transferable coarse-grain model of crystalline hexahydro-1,3,5-trinitro-s-triazine (RDX) that can be used with the energy conserving dissipative particle dynamics method. The model is an extension of a recently reported one-site model of RDX that was developed by using a force-matching method. The density-dependent forces in that original model are provided through an interpolation scheme that poorly conserves energy. The development of the new model presented in this work first involved a multi-objective procedure to improve the structural and thermodynamic properties of the previous model, followed by the inclusion of the density dependency via a conservative form of the force field that conserves energy. The new model accurately predicts the density, structure, pressure-volume isotherm, bulk modulus, and elastic constants of the RDX crystal at ambient pressure and exhibits transferability to a liquid phase at melt conditions.

  5. Chemical bond as a test of density-gradient expansions for kinetic and exchange energies

    NASA Astrophysics Data System (ADS)

    Perdew, John P.; Levy, Mel; Painter, G. S.; Wei, Siqing; Lagowski, Jolanta B.

    1988-01-01

    Errors in kinetic and exchange contributions to the molecular bonding energy are assessed for approximate density functionals by reference to near-exact Hartree-Fock values. From the molecular calculations of Allan et al.and of Lee and Ghosh, it is demonstrated that the density-gradient expansion does not accurately describe the noninteracting kinetic contribution to the bonding energy, even when this expansion is carried to fourth order and applied in its spin-density-functional form to accurate Hartree-Fock densities. In a related study, it is demonstrated that the overbinding of molecules such as N2 and F2, which occurs in the local-spin-density (LSD) approximation for the exchange-correlation energy, is not attributable to errors in the self-consistent LSD densities. Contrary to expectations based upon the Gunnarsson-Jones nodality argument, it is found that the LSD approximation for the exchange energy can seriously overbind a molecule even when bonding does not create additional nodes in the occupied valence orbitals. LSD and exact values for the exchange contribution to the bonding energy are displayed and discussed for several molecules.

  6. Chemical bond as a test of density-gradient expansions for kinetic and exchange energies

    SciTech Connect

    Perdew, J.P.; Levy, M.; Painter, G.S.; Wei, S.; Lagowski, J.B.

    1988-01-15

    Errors in kinetic and exchange contributions to the molecular bonding energy are assessed for approximate density functionals by reference to near-exact Hartree-Fock values. From the molecular calculations of Allan et al. and of Lee and Ghosh, it is demonstrated that the density-gradient expansion does not accurately describe the noninteracting kinetic contribution to the bonding energy, even when this expansion is carried to fourth order and applied in its spin-density-functional form to accurate Hartree-Fock densities. In a related study, it is demonstrated that the overbinding of molecules such as N/sub 2/ and F/sub 2/, which occurs in the local-spin-density (LSD) approximation for the exchange-correlation energy, is not attributable to errors in the self-consistent LSD densities. Contrary to expectations based upon the Gunnarsson-Jones nodality argument, it is found that the LSD approximation for the exchange energy can seriously overbind a molecule even when bonding does not create additional nodes in the occupied valence orbitals. LSD and exact values for the exchange contribution to the bonding energy are displayed and discussed for several molecules.

  7. The Impact of Neighbourhood Density on the Energy Demand of Passive Houses and on Potential Energy Sources from the Waste Flows and Solar Energy

    NASA Astrophysics Data System (ADS)

    Stupka, Robert

    This study demonstrates how the density of a neighbourhood affects its energy demand, metabolism (energy and material flows) and its ability to produce its own energy. Single-family detached houses and row townhouses were each modeled using passive solar housing guidelines with the DesignBuilder building energy simulation software. Energy demand is then modeled within neighbourhoods at two densities based on south facing windows fully un-shaded at 9:00 am, and 12:00 pm solar time on Dec. 21. The neighbourhood metabolisms were then calculated based on location and density. The potential energy supply was evaluated from the spatial characteristics of the neighbourhood (for solar) and the metabolism (municipal solid waste and wastewater flows.) The potential energy demand and supply are then compared for the varying building types and densities to determine the sensitivity of the energy supply and demand relationships.

  8. Unbiased Estimate of Dark Energy Density from Type Ia Supernova Data

    NASA Astrophysics Data System (ADS)

    Wang, Yun; Lovelace, Geoffrey

    2001-12-01

    Type Ia supernovae (SNe Ia) are currently the best probes of the dark energy in the universe. To constrain the nature of dark energy, we assume a flat universe and that the weak energy condition is satisfied, and we allow the density of dark energy, ρX(z), to be an arbitrary function of redshift. Using simulated data from a space-based SN pencil-beam survey, we find that by optimizing the number of parameters used to parameterize the dimensionless dark energy density, f(z)=ρX(z)/ρX(z=0), we can obtain an unbiased estimate of both f(z) and the fractional matter density of the universe, Ωm. A plausible SN pencil-beam survey (with a square degree field of view and for an observational duration of 1 yr) can yield about 2000 SNe Ia with 0<=z<=2. Such a survey in space would yield SN peak luminosities with a combined intrinsic and observational dispersion of σ(mint)=0.16 mag. We find that for such an idealized survey, Ωm can be measured to 10% accuracy, and the dark energy density can be estimated to ~20% to z~1.5, and ~20%-40% to z~2, depending on the time dependence of the true dark energy density. Dark energy densities that vary more slowly can be more accurately measured. For the anticipated Supernova/Acceleration Probe (SNAP) mission, Ωm can be measured to 14% accuracy, and the dark energy density can be estimated to ~20% to z~1.2. Our results suggest that SNAP may gain much sensitivity to the time dependence of the dark energy density and Ωm by devoting more observational time to the central pencil-beam fields to obtain more SNe Ia at z>1.2. We use both a maximum likelihood analysis and a Monte Carlo analysis (when appropriate) to determine the errors of estimated parameters. We find that the Monte Carlo analysis gives a more accurate estimate of the dark energy density than the maximum likelihood analysis.

  9. Assessment of satiety depends on the energy density and portion size of the test meal

    PubMed Central

    Williams, Rachel A.; Roe, Liane S.; Rolls, Barbara J.

    2013-01-01

    Objective Foods that enhance satiety can reduce overconsumption, but the availability of large portions of energy-dense foods may counter their benefits. We tested the influence on meal energy intake of varying the energy density and portion size of food consumed after a preload shown to promote satiety. Design and Methods In a crossover design, 46 women were served lunch on six days. On four days they ate a compulsory salad (300 g, 0.33 kcal/g). Unlike previous studies, instead of varying the preload, the subsequent test meal of pasta was varied between standard and increased levels of both energy density (1.25 or 1.66 kcal/g) and portion size (450 or 600 g). On two control days a salad was not served. Results Following the salad, the energy density and portion size of the test meal independently affected meal energy intake (both p<0.02). Serving the higher-energy-dense pasta increased test meal intake by 153±19 kcal and serving the larger portion of pasta increased test meal intake by 40±16 kcal. Compared to having no salad, consuming the salad decreased test meal intake by 123±18 kcal. Conclusions The effect of satiety-enhancing foods can be influenced by the energy density and portion size of other foods at the meal. PMID:23929544

  10. Dietary energy density is associated with obesity and the metabolic syndrome in U.S. adults

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rising obesity rates have been linked to the consumption of energy-dense diets. We examined whether dietary energy density was associated with obesity and related disorders, including insulin resistance and the metabolic syndrome. We conducted a cross-sectional study using nationally representative ...

  11. Impact of a School Nutrition Policy to Middle School Students Dietary Energy Density

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The consumption of energy-dense foods has been associated with rising obesity rates and linked to the metabolic syndrome. Reducing dietary energy density (DED) is an important strategy to address obesity, but few studies have examined the effect of nutrition policies on children's DED. The Texas Pub...

  12. The effect of cell size and channel density on neuronal information encoding and energy efficiency

    PubMed Central

    Sengupta, Biswa; Faisal, A Aldo; Laughlin, Simon B; Niven, Jeremy E

    2013-01-01

    Identifying the determinants of neuronal energy consumption and their relationship to information coding is critical to understanding neuronal function and evolution. Three of the main determinants are cell size, ion channel density, and stimulus statistics. Here we investigate their impact on neuronal energy consumption and information coding by comparing single-compartment spiking neuron models of different sizes with different densities of stochastic voltage-gated Na+ and K+ channels and different statistics of synaptic inputs. The largest compartments have the highest information rates but the lowest energy efficiency for a given voltage-gated ion channel density, and the highest signaling efficiency (bits spike−1) for a given firing rate. For a given cell size, our models revealed that the ion channel density that maximizes energy efficiency is lower than that maximizing information rate. Low rates of small synaptic inputs improve energy efficiency but the highest information rates occur with higher rates and larger inputs. These relationships produce a Law of Diminishing Returns that penalizes costly excess information coding capacity, promoting the reduction of cell size, channel density, and input stimuli to the minimum possible, suggesting that the trade-off between energy and information has influenced all aspects of neuronal anatomy and physiology. PMID:23778164

  13. Ambipolar zinc-polyiodide electrolyte for a high-energy density aqueous redox flow battery.

    PubMed

    Li, Bin; Nie, Zimin; Vijayakumar, M; Li, Guosheng; Liu, Jun; Sprenkle, Vincent; Wang, Wei

    2015-01-01

    Redox flow batteries are receiving wide attention for electrochemical energy storage due to their unique architecture and advantages, but progress has so far been limited by their low energy density (~25 Wh l(-1)). Here we report a high-energy density aqueous zinc-polyiodide flow battery. Using the highly soluble iodide/triiodide redox couple, a discharge energy density of 167 Wh l(-1) is demonstrated with a near-neutral 5.0 M ZnI2 electrolyte. Nuclear magnetic resonance study and density functional theory-based simulation along with flow test data indicate that the addition of an alcohol (ethanol) induces ligand formation between oxygen on the hydroxyl group and the zinc ions, which expands the stable electrolyte temperature window to from -20 to 50 °C, while ameliorating the zinc dendrite. With the high-energy density and its benign nature free from strong acids and corrosive components, zinc-polyiodide flow battery is a promising candidate for various energy storage applications. PMID:25709083

  14. Ambipolar zinc-polyiodide electrolyte for a high-energy density aqueous redox flow battery

    PubMed Central

    Li, Bin; Nie, Zimin; Vijayakumar, M.; Li, Guosheng; Liu, Jun; Sprenkle, Vincent; Wang, Wei

    2015-01-01

    Redox flow batteries are receiving wide attention for electrochemical energy storage due to their unique architecture and advantages, but progress has so far been limited by their low energy density (~25 Wh l−1). Here we report a high-energy density aqueous zinc-polyiodide flow battery. Using the highly soluble iodide/triiodide redox couple, a discharge energy density of 167 Wh l−1 is demonstrated with a near-neutral 5.0 M ZnI2 electrolyte. Nuclear magnetic resonance study and density functional theory-based simulation along with flow test data indicate that the addition of an alcohol (ethanol) induces ligand formation between oxygen on the hydroxyl group and the zinc ions, which expands the stable electrolyte temperature window to from −20 to 50 °C, while ameliorating the zinc dendrite. With the high-energy density and its benign nature free from strong acids and corrosive components, zinc-polyiodide flow battery is a promising candidate for various energy storage applications. PMID:25709083

  15. Evaluation of discharge energy density of antiferroelectric ceramics for pulse capacitors

    NASA Astrophysics Data System (ADS)

    Xu, Ran; Xu, Zhuo; Feng, Yujun; Wei, Xiaoyong; Tian, Jingjing; Huang, Dong

    2016-07-01

    The energy in pulse capacitors need to discharge rapidly to obtain high peak power. However, the discharge energy density of antiferroelectric (AFE) dielectrics for pulse capacitors is traditionally evaluated by hysteresis loop (defined as quasi-static method). To verify whether the quasi-static method is suitable for pulse applications, AFE ceramics Pb0.94La0.04[(Zr0.70Sn0.30)0.86Ti0.14]O3 were prepared, and their discharge energy density was calculated by hysteresis loop and pulse current (defined as dynamic method), respectively. A significant difference was found between these two kinds of results. Under 36 kV/cm, the discharge energy density calculated by 1 Hz hysteresis loop was 0.35 J/cm3 while that by pulse discharge current was only 0.18 J/cm3. It was found that the discharge energy density declined with increasing test frequency (0.1 Hz-100 Hz) and decreased further via dynamic hysteresis loop in microseconds scale. This declination can be explained by the viscous force during the motion of the domain wall. Thus, for pulse capacitors, it is more reasonable and practical to evaluate discharge energy density of AFE by pulse current than by quasi-static hysteresis loop.

  16. Energy enhancement of proton acceleration in combinational radiation pressure and bubble by optimizing plasma density

    SciTech Connect

    Bake, Muhammad Ali; Xie Baisong; Shan Zhang; Hong Xueren; Wang Hongyu

    2012-08-15

    The combinational laser radiation pressure and plasma bubble fields to accelerate protons are researched through theoretical analysis and numerical simulations. The dephasing length of the accelerated protons bunch in the front of the bubble and the density gradient effect of background plasma on the accelerating phase are analyzed in detail theoretically. The radiation damping effect on the accelerated protons energy is also considered. And it is demonstrated by two-dimensional particle-in-cell simulations that the protons bunch energy can be increased by using the background plasma with negative density gradient. However, radiation damping makes the maximal energy of the accelerated protons a little reduction.

  17. Reverse energy partitioning-An efficient algorithm for computing the density of states, partition functions, and free energy of solids.

    PubMed

    Do, Hainam; Wheatley, Richard J

    2016-08-28

    A robust and model free Monte Carlo simulation method is proposed to address the challenge in computing the classical density of states and partition function of solids. Starting from the minimum configurational energy, the algorithm partitions the entire energy range in the increasing energy direction ("upward") into subdivisions whose integrated density of states is known. When combined with the density of states computed from the "downward" energy partitioning approach [H. Do, J. D. Hirst, and R. J. Wheatley, J. Chem. Phys. 135, 174105 (2011)], the equilibrium thermodynamic properties can be evaluated at any temperature and in any phase. The method is illustrated in the context of the Lennard-Jones system and can readily be extended to other molecular systems and clusters for which the structures are known. PMID:27586913

  18. High Energy-Density Plasma Production from Plasma-Filled Rod-Pinch Diodes

    NASA Astrophysics Data System (ADS)

    Schumer, J. W.; Weber, B. V.; Mosher, D.; Apruzese, J. P.

    2008-04-01

    The Plasma-Filled Rod-Pinch diode (PFRP) concentrates a 100-ns, 500-kA, >MeV electron-beam onto the tip of a tapered tungsten rod, generating a High Energy Density Plasma (HEDP). The HEDP (warm dense plasma) is created by deposition of a high-power-density (40 TW/cm^2) electron-beam into solid-density tungsten. The diode current and voltage has been shown to be controllably modified between 260 kA and 1.8 MV to 770 kA and 0.45 MV by increasing the initial plasma-fill density. At the time of peak energy density, analytic estimates using a 0-d self-similar MHD model predict a solid-density (20 g/cm^3) tungsten plasma with 25 eV temperature, 16 Mbar pressure, and 2.4 MJ/cm^3 thermal energy density prior to rapid plasma expansion (after about 10 ns). Temperature and ionization state increase after this time as the rod-tip rapidly expands. This PFRP approach may have advantages for HEDP research. Various applications include high-fluence flash radiography and the study of equation-of-state of materials. Current research results will be presented.

  19. Interpolating moving least-squares methods for fitting potential energy surfaces : computing high-density potential energy surface data from low-density ab initio data points.

    SciTech Connect

    Dawes, R.; Thompson, D. L.; Guo, Y.; Wagner, A. F.; Minkoff, M.; Chemistry; Univ. of Missouri-Columbia; Oklahoma State Univ.

    2007-05-11

    A highly accurate and efficient method for molecular global potential energy surface (PES) construction and fitting is demonstrated. An interpolating-moving-least-squares (IMLS)-based method is developed using low-density ab initio Hessian values to compute high-density PES parameters suitable for accurate and efficient PES representation. The method is automated and flexible so that a PES can be optimally generated for classical trajectories, spectroscopy, or other applications. Two important bottlenecks for fitting PESs are addressed. First, high accuracy is obtained using a minimal density of ab initio points, thus overcoming the bottleneck of ab initio point generation faced in applications of modified-Shepard-based methods. Second, high efficiency is also possible (suitable when a huge number of potential energy and gradient evaluations are required during a trajectory calculation). This overcomes the bottleneck in high-order IMLS-based methods, i.e., the high cost/accuracy ratio for potential energy evaluations. The result is a set of hybrid IMLS methods in which high-order IMLS is used with low-density ab initio Hessian data to compute a dense grid of points at which the energy, Hessian, or even high-order IMLS fitting parameters are stored. A series of hybrid methods is then possible as these data can be used for neural network fitting, modified-Shepard interpolation, or approximate IMLS. Results that are indicative of the accuracy, efficiency, and scalability are presented for one-dimensional model potentials as well as for three-dimensional (HCN) and six-dimensional (HOOH) molecular PESs

  20. Graphene and carbon nanotube composite electrodes for supercapacitors with ultra-high energy density.

    PubMed

    Cheng, Qian; Tang, Jie; Ma, Jun; Zhang, Han; Shinya, Norio; Qin, Lu-Chang

    2011-10-21

    We describe a graphene and single-walled carbon nanotube (SWCNT) composite film prepared by a blending process for use as electrodes in high energy density supercapacitors. Specific capacitances of 290.6 F g(-1) and 201.0 F g(-1) have been obtained for a single electrode in aqueous and organic electrolytes, respectively, using a more practical two-electrode testing system. In the organic electrolyte the energy density reached 62.8 Wh kg(-1) and the power density reached 58.5 kW kg(-1). The addition of single-walled carbon nanotubes raised the energy density by 23% and power density by 31% more than the graphene electrodes. The graphene/CNT electrodes exhibited an ultra-high energy density of 155.6 Wh kg(-1) in ionic liquid at room temperature. In addition, the specific capacitance increased by 29% after 1000 cycles in ionic liquid, indicating their excellent cyclicity. The SWCNTs acted as a conductive additive, spacer, and binder in the graphene/CNT supercapacitors. This work suggests that our graphene/CNT supercapacitors can be comparable to NiMH batteries in performance and are promising for applications in hybrid vehicles and electric vehicles. PMID:21887427

  1. Link between Food Energy Density and Body Weight Changes in Obese Adults

    PubMed Central

    Stelmach-Mardas, Marta; Rodacki, Tomasz; Dobrowolska-Iwanek, Justyna; Brzozowska, Anna; Walkowiak, Jarosław; Wojtanowska-Krosniak, Agnieszka; Zagrodzki, Paweł; Bechthold, Angela; Mardas, Marcin; Boeing, Heiner

    2016-01-01

    Regulating the energy density of food could be used as a novel approach for successful body weight reduction in clinical practice. The aim of this study was to conduct a systemic review of the literature on the relationship between food energy density and body weight changes in obese adults to obtain solid evidence supporting this approach. The search process was based on the selection of publications in the English language listed in public databases. A meta-analysis was performed to combine individual study results. Thirteen experimental and observational studies were identified and included in the final analysis. The analyzed populations consist of 3628 individuals aged 18 to 66 years. The studies varied greatly in terms of study populations, study design and applied dietary approaches. The meta-analysis revealed a significant association between low energy density foods and body weight reduction, i.e., −0.53 kg when low energy density foods were eaten (95% CI: −0.88, −0.19). In conclusions, this study adds evidence which supports the energy density of food as a simple but effective measure to manage weight in the obese with the aim of weight reduction. PMID:27104562

  2. Theoretical Limits of Energy Density in Silicon-Carbon Composite Anode Based Lithium Ion Batteries

    PubMed Central

    Dash, Ranjan; Pannala, Sreekanth

    2016-01-01

    Silicon (Si) is under consideration as a potential next-generation anode material for the lithium ion battery (LIB). Experimental reports of up to 40% increase in energy density of Si anode based LIBs (Si-LIBs) have been reported in literature. However, this increase in energy density is achieved when the Si-LIB is allowed to swell (volumetrically expand) more than graphite based LIB (graphite-LIB) and beyond practical limits. The volume expansion of LIB electrodes should be negligible for applications such as automotive or mobile devices. We determine the theoretical bounds of Si composition in a Si–carbon composite (SCC) based anode to maximize the volumetric energy density of a LIB by constraining the external dimensions of the anode during charging. The porosity of the SCC anode is adjusted to accommodate the volume expansion during lithiation. The calculated threshold value of Si was then used to determine the possible volumetric energy densities of LIBs with SCC anode (SCC-LIBs) and the potential improvement over graphite-LIBs. The level of improvement in volumetric and gravimetric energy density of SCC-LIBs with constrained volume is predicted to be less than 10% to ensure the battery has similar power characteristics of graphite-LIBs. PMID:27311811

  3. Theoretical Limits of Energy Density in Silicon-Carbon Composite Anode Based Lithium Ion Batteries.

    PubMed

    Dash, Ranjan; Pannala, Sreekanth

    2016-01-01

    Silicon (Si) is under consideration as a potential next-generation anode material for the lithium ion battery (LIB). Experimental reports of up to 40% increase in energy density of Si anode based LIBs (Si-LIBs) have been reported in literature. However, this increase in energy density is achieved when the Si-LIB is allowed to swell (volumetrically expand) more than graphite based LIB (graphite-LIB) and beyond practical limits. The volume expansion of LIB electrodes should be negligible for applications such as automotive or mobile devices. We determine the theoretical bounds of Si composition in a Si-carbon composite (SCC) based anode to maximize the volumetric energy density of a LIB by constraining the external dimensions of the anode during charging. The porosity of the SCC anode is adjusted to accommodate the volume expansion during lithiation. The calculated threshold value of Si was then used to determine the possible volumetric energy densities of LIBs with SCC anode (SCC-LIBs) and the potential improvement over graphite-LIBs. The level of improvement in volumetric and gravimetric energy density of SCC-LIBs with constrained volume is predicted to be less than 10% to ensure the battery has similar power characteristics of graphite-LIBs. PMID:27311811

  4. Theoretical Limits of Energy Density in Silicon-Carbon Composite Anode Based Lithium Ion Batteries

    NASA Astrophysics Data System (ADS)

    Dash, Ranjan; Pannala, Sreekanth

    2016-06-01

    Silicon (Si) is under consideration as a potential next-generation anode material for the lithium ion battery (LIB). Experimental reports of up to 40% increase in energy density of Si anode based LIBs (Si-LIBs) have been reported in literature. However, this increase in energy density is achieved when the Si-LIB is allowed to swell (volumetrically expand) more than graphite based LIB (graphite-LIB) and beyond practical limits. The volume expansion of LIB electrodes should be negligible for applications such as automotive or mobile devices. We determine the theoretical bounds of Si composition in a Si–carbon composite (SCC) based anode to maximize the volumetric energy density of a LIB by constraining the external dimensions of the anode during charging. The porosity of the SCC anode is adjusted to accommodate the volume expansion during lithiation. The calculated threshold value of Si was then used to determine the possible volumetric energy densities of LIBs with SCC anode (SCC-LIBs) and the potential improvement over graphite-LIBs. The level of improvement in volumetric and gravimetric energy density of SCC-LIBs with constrained volume is predicted to be less than 10% to ensure the battery has similar power characteristics of graphite-LIBs.

  5. Thermodynamic analysis of energy density in pressure retarded osmosis: The impact of solution volumes and costs

    SciTech Connect

    Reimund, Kevin K.; McCutcheon, Jeffrey R.; Wilson, Aaron D.

    2015-08-01

    A general method was developed for estimating the volumetric energy efficiency of pressure retarded osmosis via pressure-volume analysis of a membrane process. The resulting model requires only the osmotic pressure, π, and mass fraction, w, of water in the concentrated and dilute feed solutions to estimate the maximum achievable specific energy density, uu, as a function of operating pressure. The model is independent of any membrane or module properties. This method utilizes equilibrium analysis to specify the volumetric mixing fraction of concentrated and dilute solution as a function of operating pressure, and provides results for the total volumetric energy density of similar order to more complex models for the mixing of seawater and riverwater. Within the framework of this analysis, the total volumetric energy density is maximized, for an idealized case, when the operating pressure is π/(1+√w⁻¹), which is lower than the maximum power density operating pressure, Δπ/2, derived elsewhere, and is a function of the solute osmotic pressure at a given mass fraction. It was also found that a minimum 1.45 kmol of ideal solute is required to produce 1 kWh of energy while a system operating at “maximum power density operating pressure” requires at least 2.9 kmol. Utilizing this methodology, it is possible to examine the effects of volumetric solution cost, operation of a module at various pressure, and operation of a constant pressure module with various feed.

  6. Link between Food Energy Density and Body Weight Changes in Obese Adults.

    PubMed

    Stelmach-Mardas, Marta; Rodacki, Tomasz; Dobrowolska-Iwanek, Justyna; Brzozowska, Anna; Walkowiak, Jarosław; Wojtanowska-Krosniak, Agnieszka; Zagrodzki, Paweł; Bechthold, Angela; Mardas, Marcin; Boeing, Heiner

    2016-01-01

    Regulating the energy density of food could be used as a novel approach for successful body weight reduction in clinical practice. The aim of this study was to conduct a systemic review of the literature on the relationship between food energy density and body weight changes in obese adults to obtain solid evidence supporting this approach. The search process was based on the selection of publications in the English language listed in public databases. A meta-analysis was performed to combine individual study results. Thirteen experimental and observational studies were identified and included in the final analysis. The analyzed populations consist of 3628 individuals aged 18 to 66 years. The studies varied greatly in terms of study populations, study design and applied dietary approaches. The meta-analysis revealed a significant association between low energy density foods and body weight reduction, i.e., -0.53 kg when low energy density foods were eaten (95% CI: -0.88, -0.19). In conclusions, this study adds evidence which supports the energy density of food as a simple but effective measure to manage weight in the obese with the aim of weight reduction. PMID:27104562

  7. Effect of energy density on the machining character of C/SiC composites by picosecond laser

    NASA Astrophysics Data System (ADS)

    Liu, Yongsheng; Wang, Chunhui; Li, Weinan; Yang, Xiaojun; Zhang, Qing; Cheng, Laifei; Zhang, Litong

    2014-09-01

    The effect of laser energy density on the machining character of C/SiC composites by picosecond laser was investigated using two machining modes: single ring line and helical lines scanning. For single ring line scanning mode, the width and depth of machining grooves increased nonlinearly with the increase of laser energy density. Moreover, periodic surface structures (ripples) were generated at relative low laser energy density and disappeared at high energy density. With the increasing energy density, the oxygen content of machining debris increased dramatically. For helical lines scanning mode, the depth of machining grooves increased nonlinearly with the increasing laser energy density. With the increasing energy density, the oxygen content of machining debris also increased dramatically. The machining character showed as nano-scale laser-induced ripples, pores, strip structures and bubble pits. Finally, micro-holes of high aspect ratio were obtained in the mode of helical lines scanning by removing multiple layers.

  8. Energy conversion method in the ocean using the density difference of water

    SciTech Connect

    Mochizuki, H.; Mitsuhashi, W.

    1981-01-01

    A new method which produces energy from the ocean by utilizing the density difference of water, by means of a ''chimney effect'', is proposed. Density difference of water in the ocean occurs in two ways, namely differences of consistency and water temperature. For instance, fresh river water and melting flows and icebergs are pointed out as some origins of the former, while thermal effects of volcanoes and hot springs may account for the latter. 5 refs.

  9. An explanation for the tiny value of the cosmological constant and the low vacuum energy density

    NASA Astrophysics Data System (ADS)

    Nassif, Cláudio

    2015-09-01

    The paper aims to provide an explanation for the tiny value of the cosmological constant and the low vacuum energy density to represent the dark energy. To accomplish this, we will search for a fundamental principle of symmetry in space-time by means of the elimination of the classical idea of rest, by including an invariant minimum limit of speed in the subatomic world. Such a minimum speed, unattainable by particles, represents a preferred reference frame associated with a background field that breaks down the Lorentz symmetry. The metric of the flat space-time shall include the presence of a uniform vacuum energy density, which leads to a negative pressure at cosmological length scales. Thus, the equation of state for the cosmological constant [ p(pressure) (energy density)] naturally emerges from such a space-time with an energy barrier of a minimum speed. The tiny values of the cosmological constant and the vacuum energy density will be successfully obtained, being in agreement with the observational results of Perlmutter, Schmidt and Riess.

  10. A High Power Density Single-Phase PWM Rectifier With Active Ripple Energy Storage

    SciTech Connect

    Wang, Ruxi; Wang, Fei; Boroyevich, Dushan; Burgos, Rolando; Lai, Rixin; Ning, Puqi; Rajashekara, Kaushik

    2011-01-01

    It is well known that single-phase pulse width modulation rectifiers have second-order harmonic currents and corresponding ripple voltages on the dc bus. The low-frequency harmonic current is normally filtered using a bulk capacitor in the bus, which results in low power density. However, pursuing high power density in converter design is a very important goal in the aerospace applications. This paper studies methods for reducing the energy storage capacitor for single-phase rectifiers. The minimum ripple energy storage requirement is derived independently of a specific topology. Based on theminimum ripple energy requirement, the feasibility of the active capacitor s reduction schemes is verified. Then, we propose a bidirectional buck boost converter as the ripple energy storage circuit, which can effectively reduce the energy storage capacitance. The analysis and design are validated by simulation and experimental results.

  11. Impact of the matter density uncertainty on the dark energy reconstruction

    SciTech Connect

    Avelino, P. P.

    2009-04-15

    In this paper we study the impact of the fractional matter density uncertainty in the reconstruction of the equation of state of dark energy. We consider both standard reconstruction methods, based on the dynamical effect that dark energy has on the expansion of the Universe, as well as nonstandard methods, in which the evolution of the dark energy equation of state with redshift is inferred through the variation of fundamental couplings such as the fine-structure constant, {alpha}, or the proton-to-electron mass ratio, {mu}. We show that the negative impact of the matter density uncertainty in the dark energy reconstruction using varying couplings may be very small compared to standard reconstruction methods. We also briefly discuss other fundamental questions which need to be answered before varying couplings can be successfully used to probe the nature of the dark energy.

  12. US Heavy Ion Beam Research for High Energy Density Physics Applications and Fusion

    SciTech Connect

    Davidson, R.C.; Logan, B.G.; Barnard, J.J.; Bieniosek, F.M.; Briggs, R.J.; et al.

    2005-09-19

    Key scientific results from recent experiments, modeling tools, and heavy ion accelerator research are summarized that explore ways to investigate the properties of high energy density matter in heavy-ion-driven targets, in particular, strongly-coupled plasmas at 0.01 to 0.1 times solid density for studies of warm dense matter, which is a frontier area in high energy density physics. Pursuit of these near-term objectives has resulted in many innovations that will ultimately benefit heavy ion inertial fusion energy. These include: neutralized ion beam compression and focusing, which hold the promise of greatly improving the stage between the accelerator and the target chamber in a fusion power plant; and the Pulse Line Ion Accelerator (PLIA), which may lead to compact, low-cost modular linac drivers.

  13. Level densities of iron isotopes and lower-energy enhancement of y-strength function

    SciTech Connect

    Voinov, A V; Grimes, S M; Agvaanluvsan, U; Algin, E; Belgya, T; Brune, C R; Guttormsen, M; Hornish, M J; Massey, T N; Mitchell, G; Rekstad, J; Schiller, A; Siem, S

    2005-08-30

    The neutron spectrum from the {sup 55}Mn(d,n){sup 56}Fe reaction has been measured at E{sub d} = 7 MeV. The level density of {sup 56}Fe obtained from neutron evaporation spectrum has been compared to the level density from Oslo-type {sup 57}Fe({sup 3}He, a{gamma}){sup 56}Fe experiment [1]. The good agreement supports the recent results [1, 8] including an availability of a low-energy enhancement in the {gamma}-strength function for iron isotopes. The new level density function allowed us to investigate an excitation energy dependence of this enhancement, which is shown to increase with increasing excitation energy.

  14. Exploration of Plasma Jets Approach to High Energy Density Physics. Final report

    SciTech Connect

    Chen, Chiping

    2013-08-26

    High-energy-density laboratory plasma (HEDLP) physics is an emerging, important area of research in plasma physics, nuclear physics, astrophysics, and particle acceleration. While the HEDLP regime occurs at extreme conditions which are often found naturally in space but not on the earth, it may be accessible by colliding high intensity plasmas such as high-energy-density plasma jets, plasmoids or compact toroids from plasma guns. The physics of plasma jets is investigated in the context of high energy density laboratory plasma research. This report summarizes results of theoretical and computational investigation of a plasma jet undergoing adiabatic compression and adiabatic expansion. A root-mean-squared (rms) envelope theory of plasma jets is developed. Comparison between theory and experiment is made. Good agreement between theory and experiment is found.

  15. US Heavy Ion Beam Research for Energy Density Physics Applicationsand Fusion

    SciTech Connect

    Davidson, R.C.; Logan, B.G.; Barnard, J.J.; Bieniosek, F.M.; Briggs, R.J.; Callahan D.A.; Kireeff Covo, M.; Celata, C.M.; Cohen, R.H.; Coleman, J.E.; Debonnel, C.S.; Grote, D.P.; Efthimiom, P.C.; Eylon, S.; Friedman, A.; Gilson, E.P.; Grisham, L.R.; Henestroza, E.; Kaganovich,I.D.; Kwan, J.W.; Lee, E.P.; Lee, W.W.; Leitner, M.; Lund, S.M.; Meier,W.R.; Molvik, A.W.; Olson, C.L.; Penn, G.E.; Qin, H.; Roy, P.K.; Rose,D.V.; Sefkow, A.; Seidl, P.A.; Sharp, W.M.; Startsev, E.A.; Tabak, M.; Thoma, C.; Vay, J-L; Wadron, W.L.; Wurtele, J.S.; Welch, D.R.; Westenskow, G.A.; Yu, S.S.

    2005-09-01

    Key scientific results from recent experiments, modeling tools, and heavy ion accelerator research are summarized that explore ways to investigate the properties of high energy density matter in heavy-ion-driven targets, in particular, strongly-coupled plasmas at 0.01 to 0.1 times solid density for studies of warm dense matter, which is a frontier area in high energy density physics. Pursuit of these near-term objectives has resulted in many innovations that will ultimately benefit heavy ion inertial fusion energy. These include: neutralized ion beam compression and focusing, which hold the promise of greatly improving the stage between the accelerator and the target chamber in a fusion power plant; and the Pulse Line Ion Accelerator (PLIA), which may lead to compact, low-cost modular linac drivers.

  16. Antiferroelectric Thin-Film Capacitors with High Energy-Storage Densities, Low Energy Losses, and Fast Discharge Times.

    PubMed

    Ahn, Chang Won; Amarsanaa, Gantsooj; Won, Sung Sik; Chae, Song A; Lee, Dae Su; Kim, Ill Won

    2015-12-01

    We demonstrate a capacitor with high energy densities, low energy losses, fast discharge times, and high temperature stabilities, based on Pb(0.97)Y(0.02)[(Zr(0.6)Sn(0.4))(0.925)Ti(0.075)]O3 (PYZST) antiferroelectric thin-films. PYZST thin-films exhibited a high recoverable energy density of U(reco) = 21.0 J/cm(3) with a high energy-storage efficiency of η = 91.9% under an electric field of 1300 kV/cm, providing faster microsecond discharge times than those of commercial polypropylene capacitors. Moreover, PYZST thin-films exhibited high temperature stabilities with regard to their energy-storage properties over temperatures ranging from room temperature to 100 °C and also exhibited strong charge-discharge fatigue endurance up to 1 × 10(7) cycles. PMID:26606502

  17. Towards improved local hybrid functionals by calibration of exchange-energy densities

    SciTech Connect

    Arbuznikov, Alexei V. E-mail: martin.kaupp@tu-berlin.de; Kaupp, Martin E-mail: martin.kaupp@tu-berlin.de

    2014-11-28

    A new approach for the calibration of (semi-)local and exact exchange-energy densities in the context of local hybrid functionals is reported. The calibration functions are derived from only the electron density and its spatial derivatives, avoiding spatial derivatives of the exact-exchange energy density or other computationally unfavorable contributions. The calibration functions fulfill the seven more important out of nine known exact constraints. It is shown that calibration improves substantially the definition of a non-dynamical correlation energy term for generalized gradient approximation (GGA)-based local hybrids. Moreover, gauge artifacts in the potential-energy curves of noble-gas dimers may be corrected by calibration. The developed calibration functions are then evaluated for a large range of energy-related properties (atomization energies, reaction barriers, ionization potentials, electron affinities, and total atomic energies) of three sets of local hybrids, using a simple one-parameter local-mixing. The functionals are based on (a) local spin-density approximation (LSDA) or (b) Perdew-Burke-Ernzerhof (PBE) exchange and correlation, and on (c) Becke-88 (B88) exchange and Lee-Yang-Parr (LYP) correlation. While the uncalibrated GGA-based functionals usually provide very poor thermochemical data, calibration allows a dramatic improvement, accompanied by only a small deterioration of reaction barriers. In particular, an optimized BLYP-based local-hybrid functional has been found that is a substantial improvement over the underlying global hybrids, as well as over previously reported LSDA-based local hybrids. It is expected that the present calibration approach will pave the way towards new generations of more accurate hyper-GGA functionals based on a local mixing of exchange-energy densities.

  18. Towards improved local hybrid functionals by calibration of exchange-energy densities

    NASA Astrophysics Data System (ADS)

    Arbuznikov, Alexei V.; Kaupp, Martin

    2014-11-01

    A new approach for the calibration of (semi-)local and exact exchange-energy densities in the context of local hybrid functionals is reported. The calibration functions are derived from only the electron density and its spatial derivatives, avoiding spatial derivatives of the exact-exchange energy density or other computationally unfavorable contributions. The calibration functions fulfill the seven more important out of nine known exact constraints. It is shown that calibration improves substantially the definition of a non-dynamical correlation energy term for generalized gradient approximation (GGA)-based local hybrids. Moreover, gauge artifacts in the potential-energy curves of noble-gas dimers may be corrected by calibration. The developed calibration functions are then evaluated for a large range of energy-related properties (atomization energies, reaction barriers, ionization potentials, electron affinities, and total atomic energies) of three sets of local hybrids, using a simple one-parameter local-mixing. The functionals are based on (a) local spin-density approximation (LSDA) or (b) Perdew-Burke-Ernzerhof (PBE) exchange and correlation, and on (c) Becke-88 (B88) exchange and Lee-Yang-Parr (LYP) correlation. While the uncalibrated GGA-based functionals usually provide very poor thermochemical data, calibration allows a dramatic improvement, accompanied by only a small deterioration of reaction barriers. In particular, an optimized BLYP-based local-hybrid functional has been found that is a substantial improvement over the underlying global hybrids, as well as over previously reported LSDA-based local hybrids. It is expected that the present calibration approach will pave the way towards new generations of more accurate hyper-GGA functionals based on a local mixing of exchange-energy densities.

  19. Associations between eating frequency and energy intake, energy density, diet quality and body weight status in adults from the USA.

    PubMed

    Zhu, Yong; Hollis, James H

    2016-06-01

    To investigate associations between eating frequency and energy intake, energy density, diet quality and body weight status in adults from the USA, combined data from the 2009-2010 and 2011-2012 National Health and Nutrition Examination Survey (NHANES) were used in this study. The first 24-h dietary recall data from eligible participants (4017 men and 3774 women) were used to calculate eating frequency, as well as energy intake, energy density and the Healthy Eating Index 2010 (HEI-2010), as a measure of diet quality. BMI and waist circumference were obtained from the NHANES body measures data. Adjusting for confounding socio-demographic characteristics and lifestyle factors, a higher eating frequency was significantly associated with higher energy intake in both men and women (both P<0·001). A higher eating frequency was also significantly associated with lower energy density in both men and women, regardless of whether beverage or water intake was included in the calculation of energy density (all P<0·01). Moreover, there was a significant positive association between eating frequency and the HEI-2010 total score in both men and women (both P<0·001). Eating frequency was inversely associated with BMI in women (P=0·003), as well as waist circumference in both men (P=0·032) and women (P=0·010). Results from the present study suggested that adults with a higher eating frequency in the USA had a healthier diet with lower energy density and better diet quality, and eating frequency was inversely associated with body weight status. PMID:27109636

  20. Coaxial wet-spun yarn supercapacitors for high-energy density and safe wearable electronics.

    PubMed

    Kou, Liang; Huang, Tieqi; Zheng, Bingna; Han, Yi; Zhao, Xiaoli; Gopalsamy, Karthikeyan; Sun, Haiyan; Gao, Chao

    2014-01-01

    Yarn supercapacitors have great potential in future portable and wearable electronics because of their tiny volume, flexibility and weavability. However, low-energy density limits their development in the area of wearable high-energy density devices. How to enhance their energy densities while retaining their high-power densities is a critical challenge for yarn supercapacitor development. Here we propose a coaxial wet-spinning assembly approach to continuously spin polyelectrolyte-wrapped graphene/carbon nanotube core-sheath fibres, which are used directly as safe electrodes to assembly two-ply yarn supercapacitors. The yarn supercapacitors using liquid and solid electrolytes show ultra-high capacitances of 269 and 177 mF cm(-2) and energy densities of 5.91 and 3.84 μWh cm(-2), respectively. A cloth supercapacitor superior to commercial capacitor is further interwoven from two individual 40-cm-long coaxial fibres. The combination of scalable coaxial wet-spinning technology and excellent performance of yarn supercapacitors paves the way to wearable and safe electronics. PMID:24786366

  1. Coaxial wet-spun yarn supercapacitors for high-energy density and safe wearable electronics

    PubMed Central

    Kou, Liang; Huang, Tieqi; Zheng, Bingna; Han, Yi; Zhao, Xiaoli; Gopalsamy, Karthikeyan; Sun, Haiyan; Gao, Chao

    2014-01-01

    Yarn supercapacitors have great potential in future portable and wearable electronics because of their tiny volume, flexibility and weavability. However, low-energy density limits their development in the area of wearable high-energy density devices. How to enhance their energy densities while retaining their high-power densities is a critical challenge for yarn supercapacitor development. Here we propose a coaxial wet-spinning assembly approach to continuously spin polyelectrolyte-wrapped graphene/carbon nanotube core-sheath fibres, which are used directly as safe electrodes to assembly two-ply yarn supercapacitors. The yarn supercapacitors using liquid and solid electrolytes show ultra-high capacitances of 269 and 177 mF cm−2 and energy densities of 5.91 and 3.84 μWh cm−2, respectively. A cloth supercapacitor superior to commercial capacitor is further interwoven from two individual 40-cm-long coaxial fibres. The combination of scalable coaxial wet-spinning technology and excellent performance of yarn supercapacitors paves the way to wearable and safe electronics. PMID:24786366

  2. Coaxial wet-spun yarn supercapacitors for high-energy density and safe wearable electronics

    NASA Astrophysics Data System (ADS)

    Kou, Liang; Huang, Tieqi; Zheng, Bingna; Han, Yi; Zhao, Xiaoli; Gopalsamy, Karthikeyan; Sun, Haiyan; Gao, Chao

    2014-05-01

    Yarn supercapacitors have great potential in future portable and wearable electronics because of their tiny volume, flexibility and weavability. However, low-energy density limits their development in the area of wearable high-energy density devices. How to enhance their energy densities while retaining their high-power densities is a critical challenge for yarn supercapacitor development. Here we propose a coaxial wet-spinning assembly approach to continuously spin polyelectrolyte-wrapped graphene/carbon nanotube core-sheath fibres, which are used directly as safe electrodes to assembly two-ply yarn supercapacitors. The yarn supercapacitors using liquid and solid electrolytes show ultra-high capacitances of 269 and 177 mF cm-2 and energy densities of 5.91 and 3.84 μWh cm-2, respectively. A cloth supercapacitor superior to commercial capacitor is further interwoven from two individual 40-cm-long coaxial fibres. The combination of scalable coaxial wet-spinning technology and excellent performance of yarn supercapacitors paves the way to wearable and safe electronics.

  3. Critical energy density of O(n) models in d = 3

    NASA Astrophysics Data System (ADS)

    Nerattini, Rachele; Trombettoni, Andrea; Casetti, Lapo

    2014-12-01

    A relation between O(n) models and Ising models has been recently conjectured (Casetti et al 2011 Phys. Rev. Lett. 106 057208). Such a relation, inspired by an energy landscape analysis, implies that the microcanonical density of states of an O(n) spin model on a lattice can be effectively approximated in terms of the density of states of an Ising model defined on the same lattice and with the same interactions. Were this relation exact, it would imply that the critical energy densities of all the O(n) models (i.e. the average values per spin of the O(n) Hamiltonians at their respective critical temperatures) should be equal to that of the corresponding Ising model. It is therefore worth investigating how different the critical energies are and how this difference depends on n. We compare the critical energy densities of O(n) models in three dimensions in some specific cases: the O(1) or Ising model, the O(2) or XY model, the O(3) or Heisenberg model, the O(4) model and the O(∞) or spherical model, all defined on regular cubic lattices and with ferromagnetic nearest-neighbor interactions. The values of the critical energy density in the n = 2, n = 3 and n = 4 cases are derived through a finite-size scaling analysis of data produced by means of Monte Carlo simulations on lattices with up to 1283 sites. For n = 2 and n = 3 the accuracy of previously known results has been improved. We finally derive an interpolation formula showing that the difference between the critical energy densities of O(n) models and that of the Ising model is smaller than 1% if n < 8 and never exceeds 3% for any n.

  4. Kinematics, material symmetry, and energy densities for lipid bilayers with spontaneous curvature

    PubMed Central

    Maleki, Mohsen; Seguin, Brian; Fried, Eliot

    2013-01-01

    Continuum mechanical tools are used to describe the deformation, energy density, and material symmetry of a lipid bilayer with spontaneous curvature. In contrast to conventional approaches in which lipid bilayers are modeled by material surfaces, here we rely on a three-dimensional approach in which a lipid bilayer is modeling by a shell-like body with finite thickness. In this setting, the interface between the leaflets of a lipid bilayer is assumed to coincide with the mid-surface of the corresponding shell-like body. The three-dimensional deformation gradient is found to involve the curvature tensors of the mid-surface in the spontaneous and the deformed states, the deformation gradient of the mid-surface, and the transverse deformation. Attention is also given to the coherency of the leaflets and to the area compatibility of closed lipid bilayers (i.e., vesicles). A hyperelastic constitutive theory for lipid bilayers in the liquid phase is developed. In combination, the requirements of frame-indifference and material symmetry yield a representation for the energy density of a lipid bilayer. This representation shows that three scalar invariants suffice to describe the constitutive response of a lipid bilayer exhibiting in-plane fluidity and transverse isotropy. In addition to exploring the geometrical and physical properties of these invariants, fundamental constitutively-associated kinematical quantities are emphasized. On this basis, the effect on the energy density of assuming that the lipid bilayer is incompressible is considered. Lastly, a dimension reduction argument is used to extract an areal energy density per unit area from the three-dimensional energy density. This step explains the origin of spontaneous curvature in the areal energy density. Importantly, along with a standard contribution associated with the natural curvature of lipid bilayer, our analysis indicates that constitutive asymmetry between the leaflets of the lipid bilayer gives rise to

  5. Reply to "Comment on `Single-point kinetic energy density functionals: A pointwise kinetic energy density analysis and numerical convergence investigation' "

    NASA Astrophysics Data System (ADS)

    Xia, Junchao; Carter, Emily A.

    2015-09-01

    We find that the multivalued character of the G factor as a function of the reduced gradient (s ) still exists after accounting for pseudopotential artifacts and the kinetic energy global upper bound. We also find that the VT84F functional indeed exhibits stable convergence and more reasonable results for self-consistent bulk properties compared to other generalized gradient approximation (GGA) kinetic energy density functionals (KEDFs) that we tested earlier. However, VT84F generally yields overestimated equilibrium volumes, which may result from its inability (as with all GGAs) to reproduce the G -s multivalued character. The analogous failure to predict the multivalued character of G as a function of the reduced density (d ) is also likely to be responsible for the inaccuracy of our vWGTF functionals reported earlier. Our multivaluedness analysis therefore does not impugn any particular GGA KEDF. Instead, it merely confirms the importance of pointwise analysis for improving KEDFs by emphasizing the need to resolve the multivaluedness of G with respect to various density variables.

  6. Measurements of Ion Stopping Around the Bragg Peak in High-Energy-Density Plasmas

    NASA Astrophysics Data System (ADS)

    Frenje, J. A.; Grabowski, P. E.; Li, C. K.; Séguin, F. H.; Zylstra, A. B.; Gatu Johnson, M.; Petrasso, R. D.; Glebov, V. Yu; Sangster, T. C.

    2015-11-01

    For the first time, quantitative measurements of ion stopping at energies around the Bragg peak (or peak ion stopping, which occurs at an ion velocity comparable to the average thermal electron velocity), and its dependence on electron temperature (Te ) and electron number density (ne ) in the range of 0.5-4.0 keV and 3 ×1022 to 3 ×1023 cm-3 have been conducted, respectively. It is experimentally demonstrated that the position and amplitude of the Bragg peak varies strongly with Te with ne . The importance of including quantum diffraction is also demonstrated in the stopping-power modeling of high-energy-density plasmas.

  7. Development of a high-density energy-storage capacitor for Nova

    SciTech Connect

    Haskell, D.K.; Cooper, R.A.; Sevigny, J.A.; Merritt, B.T.; Carder, B.M.; Whitham, K.

    1981-10-22

    This paper covers Maxwell's approach to developing energy storage capacitors. Based on previous capacitor designs of 3 KJ, 5 KJ and 10 KJ, the final Nova 12.5 KJ capacitor evolved. At the outset of the Nova capacitor development program, a relatively new dielectric system, polypropylene-paper-DOP, seemed to show superiority in volumetric efficiency, life, and more importantly cost. However, as a result of studies performed at Maxwell, a high-density, energy-storage capacitor was developed utilizing new high-quality, high-density paper and caster oil as the dielectric. Test data have demonstrated that the Maxwell 12.5 KJ capacitor exceeds all LLNL's qualification requirements.

  8. Employing homogeneity properties of density functionals to determine the total electronic energy

    NASA Astrophysics Data System (ADS)

    Morrison, Robert C.; Parr, Robert G.

    1996-05-01

    The exchange-correlation energy is calculated from expressions for (Exc+Tc)/2 and (Exc-Tc)/2. The expression for Exc+Tc is known exactly. The expression for Exc-Tc is not known exactly and we approximate Gxc-Tc, where Gxc=Exc+J/N, by assuming that it is a functional that is homogeneous of degree 1 in the electron density and that Tc is homogeneous of degree 0 in the electron density. The resulting formula for the total energy reduces the average of the errors in the Parr and Ghosh

    [Phys. Rev. A 51, 3564 (1995)]
    approximation by about one-half.

  9. Expansion-free evolving spheres must have inhomogeneous energy density distributions

    SciTech Connect

    Herrera, L.; Le Denmat, G.; Santos, N. O.

    2009-04-15

    In a recent paper a systematic study on shearing expansion-free spherically symmetric distributions was presented. As a particular case of such systems, the Skripkin model was mentioned, which corresponds to a nondissipative perfect fluid with a constant energy density. Here we show that such a model is inconsistent with junction conditions. It is shown that in general for any nondissipative fluid distribution, the expansion-free condition requires the energy density to be inhomogeneous. As an example we consider the case of dust, which allows for a complete integration.

  10. Ionic liquid enabled FeS2 for high-energy-density lithium-ion batteries.

    PubMed

    Evans, Tyler; Piper, Daniela Molina; Kim, Seul Cham; Han, Sang Sub; Bhat, Vinay; Oh, Kyu Hwan; Lee, Se-Hee

    2014-11-19

    High-energy-density FeS2 cathodes en-abled by a bis(trifluoromethanesulfonyl)imide (TFSI-) anion-based room temperature ionic liquid (RTIL) electrolyte are demonstrated. A TFSI-based ionic liquid (IL) significantly mitigates polysulfide dissolution, and therefore the parasitic redox shuttle mechanism, that plagues sulfur-based electrode chemistries. FeS2 stabilization with a TFSI(-) -based IL results in one of the highest energy density cathodes, 542 W h kg(-1) (normalized to cathode composite mass), reported to date. PMID:25236752

  11. Thermospheric Density Enhancements from Unexpected Energy Deposition During Bz North and Strong By Conditions

    NASA Astrophysics Data System (ADS)

    Crowley, G.

    2011-12-01

    Data from the tri-axial accelerometer on the CHAMP satellite have revealed the thermospheric density and its variability in unprecedented detail. The data often contain regions of high density located in the noon sector at high latitudes. In this paper we provide the first detailed explanation of a high latitude density enhancement observed by CHAMP, focusing on the August 24, 2005 interval. The TIMEGCM model was driven by high-fidelity high-latitude inputs specified by the Assimilative Mapping of Ionospheric Electrodynamics (AMIE) algorithm, and reproduces the density enhancements observed by CHAMP. The TIMEGCM and AMIE provide a global framework for interpretation of the CHAMP densities. Our simulations reveal that the observed significant density enhancement at high latitudes resulted from unexpectedly large amounts of energy that entered the Ionosphere-Thermosphere system at cusp latitudes during an interval of strong (40 nT) positive BY. Understanding thermospheric density is important because it exerts a drag on Low-Earth Orbiting (LEO) satellites, including the space shuttle and space station. Changes in the density and composition of the neutral atmosphere create variable satellite drag, adversely affecting spacecraft missions like maneuver planning and re-entry.

  12. How People Actually Use Thermostats

    SciTech Connect

    Meier, Alan; Aragon, Cecilia; Hurwitz, Becky; Mujumdar, Dhawal; Peffer, Therese; Perry, Daniel; Pritoni, Marco

    2010-08-15

    Residential thermostats have been a key element in controlling heating and cooling systems for over sixty years. However, today's modern programmable thermostats (PTs) are complicated and difficult for users to understand, leading to errors in operation and wasted energy. Four separate tests of usability were conducted in preparation for a larger study. These tests included personal interviews, an on-line survey, photographing actual thermostat settings, and measurements of ability to accomplish four tasks related to effective use of a PT. The interviews revealed that many occupants used the PT as an on-off switch and most demonstrated little knowledge of how to operate it. The on-line survey found that 89% of the respondents rarely or never used the PT to set a weekday or weekend program. The photographic survey (in low income homes) found that only 30% of the PTs were actually programmed. In the usability test, we found that we could quantify the difference in usability of two PTs as measured in time to accomplish tasks. Users accomplished the tasks in consistently shorter times with the touchscreen unit than with buttons. None of these studies are representative of the entire population of users but, together, they illustrate the importance of improving user interfaces in PTs.

  13. Revisiting the density scaling of the non-interacting kinetic energy.

    PubMed

    Borgoo, Alex; Teale, Andrew M; Tozer, David J

    2014-07-28

    Scaling relations play an important role in the understanding and development of approximate functionals in density functional theory. Recently, a number of these relationships have been redefined in terms of the Kohn-Sham orbitals [Calderín, Phys. Rev. A: At., Mol., Opt. Phys., 2013, 86, 032510]. For density scaling the author proposed a procedure involving a multiplicative scaling of the Kohn-Sham orbitals whilst keeping their occupation numbers fixed. In the present work, the differences between this scaling with fixed occupation numbers and that of previous studies, where the particle number change implied by the scaling was accommodated through the use of the grand canonical ensemble, are examined. We introduce the terms orbital and ensemble density scaling for these approaches, respectively. The natural ambiguity of the density scaling of the non-interacting kinetic energy functional is examined and the ancillary definitions implicit in each approach are highlighted and compared. As a consequence of these differences, Calderín recovered a homogeneity of degree 1 for the non-interacting kinetic energy functional under orbital scaling, contrasting recent work by the present authors [J. Chem. Phys., 2012, 136, 034101] where the functional was found to be inhomogeneous under ensemble density scaling. Furthermore, we show that the orbital scaling result follows directly from the linearity and the single-particle nature of the kinetic energy operator. The inhomogeneity of the non-interacting kinetic energy functional under ensemble density scaling can be quantified by defining an effective homogeneity. This quantity is shown to recover the homogeneity values for important approximate forms that are exact for limiting cases such as the uniform electron gas and one-electron systems. We argue that the ensemble density scaling provides more insight into the development of new functional forms. PMID:24710656

  14. Quantification of breast density using dual-energy mammography with liquid phantom calibration

    NASA Astrophysics Data System (ADS)

    Lam, Alfonso R.; Ding, Huanjun; Molloi, Sabee

    2014-07-01

    Breast density is a widely recognized potential risk factor for breast cancer. However, accurate quantification of breast density is a challenging task in mammography. The current use of plastic breast-equivalent phantoms for calibration provides limited accuracy in dual-energy mammography due to the chemical composition of the phantom. We implemented a breast-equivalent liquid phantom for dual-energy calibration in order to improve the accuracy of breast density measurement. To design these phantoms, three liquid compounds were chosen: water, isopropyl alcohol, and glycerol. Chemical compositions of glandular and adipose tissues, obtained from NIST database, were used as reference materials. Dual-energy signal of the liquid phantom at different breast densities (0% to 100%) and thicknesses (1 to 8 cm) were simulated. Glandular and adipose tissue thicknesses were estimated from a higher order polynomial of the signals. Our results indicated that the linear attenuation coefficients of the breast-equivalent liquid phantoms match those of the target material. Comparison between measured and known breast density data shows a linear correlation with a slope close to 1 and a non-zero intercept of 7%, while plastic phantoms showed a slope of 0.6 and a non-zero intercept of 8%. Breast density results derived from the liquid calibration phantoms showed higher accuracy than those derived from the plastic phantoms for different breast thicknesses and various tube voltages. We performed experimental phantom studies using liquid phantoms and then compared the computed breast density with those obtained using a bovine tissue model. The experimental data and the known values were in good correlation with a slope close to 1 (˜1.1). In conclusion, our results indicate that liquid phantoms are a reliable alternative for calibration in dual-energy mammography and better reproduce the chemical properties of the target material.

  15. A Method to Improve Electron Density Measurement of Cone-Beam CT Using Dual Energy Technique

    PubMed Central

    Men, Kuo; Dai, Jian-Rong; Li, Ming-Hui; Chen, Xin-Yuan; Zhang, Ke; Tian, Yuan; Huang, Peng; Xu, Ying-Jie

    2015-01-01

    Purpose. To develop a dual energy imaging method to improve the accuracy of electron density measurement with a cone-beam CT (CBCT) device. Materials and Methods. The imaging system is the XVI CBCT system on Elekta Synergy linac. Projection data were acquired with the high and low energy X-ray, respectively, to set up a basis material decomposition model. Virtual phantom simulation and phantoms experiments were carried out for quantitative evaluation of the method. Phantoms were also scanned twice with the high and low energy X-ray, respectively. The data were decomposed into projections of the two basis material coefficients according to the model set up earlier. The two sets of decomposed projections were used to reconstruct CBCT images of the basis material coefficients. Then, the images of electron densities were calculated with these CBCT images. Results. The difference between the calculated and theoretical values was within 2% and the correlation coefficient of them was about 1.0. The dual energy imaging method obtained more accurate electron density values and reduced the beam hardening artifacts obviously. Conclusion. A novel dual energy CBCT imaging method to calculate the electron densities was developed. It can acquire more accurate values and provide a platform potentially for dose calculation. PMID:26346510

  16. Rapidity profile of the initial energy density in heavy-ion collisions

    NASA Astrophysics Data System (ADS)

    Özönder, Şener; Fries, Rainer J.

    2014-03-01

    The rapidity dependence of the initial energy density in heavy-ion collisions is calculated from a three-dimensional McLerran-Venugopalan model introduced by Lam and Mahlon. This model is infrared safe since global color neutrality is enforced. In this framework, the nuclei have nonzero thickness in the longitudinal direction. This leads to Bjorken-x-dependent unintegrated gluon distribution functions, which in turn result in a rapidity-dependent initial energy density after the collision. These unintegrated distribution functions are substituted in the initial energy density expression, which has been derived for the boost-invariant case. We argue that using three-dimensional (x-dependent) unintegrated distribution functions together with the boost-invariant energy formula is consistent given that the overlap of the two nuclei lasts less than the natural time scale for the evolution of the fields (1/Qs) after the collision. The initial energy density and its rapidity dependence are important initial conditions for the quark gluon plasma and its hydrodynamic evolution.

  17. Estimating the neutrally buoyant energy density of a Rankine-cycle/fuel-cell underwater propulsion system

    NASA Astrophysics Data System (ADS)

    Waters, Daniel F.; Cadou, Christopher P.

    2014-02-01

    A unique requirement of underwater vehicles' power/energy systems is that they remain neutrally buoyant over the course of a mission. Previous work published in the Journal of Power Sources reported gross as opposed to neutrally-buoyant energy densities of an integrated solid oxide fuel cell/Rankine-cycle based power system based on the exothermic reaction of aluminum with seawater. This paper corrects this shortcoming by presenting a model for estimating system mass and using it to update the key findings of the original paper in the context of the neutral buoyancy requirement. It also presents an expanded sensitivity analysis to illustrate the influence of various design and modeling assumptions. While energy density is very sensitive to turbine efficiency (sensitivity coefficient in excess of 0.60), it is relatively insensitive to all other major design parameters (sensitivity coefficients < 0.15) like compressor efficiency, inlet water temperature, scaling methodology, etc. The neutral buoyancy requirement introduces a significant (˜15%) energy density penalty but overall the system still appears to offer factors of five to eight improvements in energy density (i.e., vehicle range/endurance) over present battery-based technologies.

  18. Advanced intermediate temperature sodium-nickel chloride batteries with ultra-high energy density

    DOE PAGESBeta

    Li, Guosheng; Lu, Xiaochuan; Kim, Jin Yong; Meinhardt, Kerry D.; Chang, Hee -Jung; Canfield, Nathan L.; Sprenkle, Vincent L.

    2016-02-11

    Here we demonstrate for the first time that planar Na-NiCl2 batteries can be operated at an intermediate temperature of 190°C with ultra-high energy density. A specific energy density of 350 Wh/kg, which is 3 times higher than that of conventional tubular Na-NiCl2 batteries operated at 280°C, was obtained for planar Na-NiCl2 batteries operated at 190°C over a long-term cell test (1000 cycles). The high energy density and superior cycle stability are attributed to the slower particle growth of the cathode materials (NaCl and Ni) at 190°C. The results reported in this work demonstrate that planar Na-NiCl2 batteries operated at anmore » intermediate temperature could greatly benefit this traditional energy storage technology by improving battery energy density, cycle life and reducing material costs.« less

  19. Effect of Radial Density Configuration on Wave Field and Energy Flow in Axially Uniform Helicon Plasma

    NASA Astrophysics Data System (ADS)

    Chang, Lei; Li, Qingchong; Zhang, Huijie; Li, Yinghong; Wu, Yun; Zhang, Bailing; Zhuang, Zhong

    2016-08-01

    The effect of the radial density configuration in terms of width, edge gradient and volume gradient on the wave field and energy flow in an axially uniform helicon plasma is studied in detail. A three-parameter function is employed to describe the density, covering uniform, parabolic, linear and Gaussian profiles. It finds that the fraction of power deposition near the plasma edge increases with density width and edge gradient, and decays in exponential and “bump-on-tail” profiles, respectively, away from the surface. The existence of a positive second-order derivative in the volume density configuration promotes the power deposition near the plasma core, which to our best knowledge has not been pointed out before. The transverse structures of wave field and current density remain almost the same during the variation of density width and gradient, confirming the robustness of the m=1 mode observed previously. However, the structure of the electric wave field changes significantly from a uniform density configuration, for which the coupling between the Trivelpiece-Gould (TG) mode and the helicon mode is very strong, to non-uniform ones. The energy flow in the cross section of helicon plasma is presented for the first time, and behaves sensitive to the density width and edge gradient but insensitive to the volume gradient. Interestingly, the radial distribution of power deposition resembles the radial profile of the axial component of current density, suggesting the control of the power deposition profile in the experiment by particularly designing the antenna geometry to excite a required axial current distribution. supported by National Natural Science Foundation of China (No. 11405271)

  20. Nonresonant energy transfers independent on the phonon densities in polyatomic liquids.

    PubMed

    Chen, Hailong; Zhang, Qiang; Guo, Xunmin; Wen, Xiewen; Li, Jiebo; Zhuang, Wei; Zheng, Junrong

    2015-01-29

    Energy-gap-dependent vibrational-energy transfers among the nitrile stretches of KSCN/KS(13)CN/KS(13)C(15)N in D2O, DMF, and formamide liquid solutions at room temperature were measured by the vibrational-energy-exchange method. The energy transfers are slower with a larger energy donor/acceptor gap, independent of the calculated instantaneous normal mode ("phonons" in liquids) densities or the terahertz absorption spectra. The energy-gap dependences of the nonresonant energy transfers cannot be described by phonon compensation mechanisms with the assumption that phonons are the instantaneous normal modes of the liquids. Instead, the experimental energy-gap dependences can be quantitatively reproduced by the dephasing mechanism. A simple theoretical derivation shows that the fast molecular motions in liquids randomize the modulations on the energy donor and acceptor by phonons and diminish the phonon compensation efficiency on energy transfer. Estimations based on the theoretical derivations suggest that, for most nonresonant intermolecular vibrational-energy transfers in liquids with energy gaps smaller than the thermal energy, the dephasing mechanism dominates the energy-transfer process. PMID:25549247

  1. Constructing multiscale gravitational energy spectra from molecular cloud surface density PDF - interplay between turbulence and gravity

    NASA Astrophysics Data System (ADS)

    Li, Guang-Xing; Burkert, Andreas

    2016-09-01

    Gravity is believed to be important on multiple physical scales in molecular clouds. However, quantitative constraints on gravity are still lacking. We derive an analytical formula which provides estimates on multiscale gravitational energy distribution using the observed surface density probability distribution function (PDF). Our analytical formalism also enables one to convert the observed column density PDF into an estimated volume density PDF, and to obtain average radial density profile ρ(r). For a region with N_col ˜ N^{-γ _N}, the gravitational energy spectra is E_p(k)˜ k^{-4(1 - 1/γ _N)}. We apply the formula to observations of molecular clouds, and find that a scaling index of -2 of the surface density PDF implies that ρ ˜ r-2 and Ep(k) ˜ k-2. The results are valid from the cloud scale (a few parsec) to around ˜ 0.1 pc. Because of the resemblance the scaling index of the gravitational energy spectrum and the that of the kinetic energy power spectrum of the Burgers turbulence (where E ˜ k-2), our result indicates that gravity can act effectively against turbulence over a multitude of physical scales. This is the critical scaling index which divides molecular clouds into two categories: clouds like Orion and Ophiuchus have shallower power laws, and the amount of gravitational energy is too large for turbulence to be effective inside the cloud. Because gravity dominates, we call this type of cloud g-type clouds. On the other hand, clouds like the California molecular cloud and the Pipe nebula have steeper power laws, and turbulence can overcome gravity if it can cascade effectively from the large scale. We call this type of cloud t-type clouds. The analytical formula can be used to determine if gravity is dominating cloud evolution when the column density PDF can be reliably determined.

  2. High-energy-density sol-gel thin film based on neat 2-cyanoethyltrimethoxysilane.

    PubMed

    Kim, Yunsang; Kathaperumal, Mohanalingam; Smith, O'Neil L; Pan, Ming-Jen; Cai, Ye; Sandhage, Kenneth H; Perry, Joseph W

    2013-03-13

    Hybrid organic-inorganic sol-gel dielectric thin films from a neat 2-cyanoethyltrimethoxysilane (CNETMS) precursor have been fabricated and their permittivity, dielectric strength, and energy density characterized. CNETMS sol-gel films possess compact, polar cyanoethyl groups and exhibit a relative permittivity of 20 at 1 kHz and breakdown strengths ranging from 650 V/μm to 250 V/μm for film thicknesses of 1.3 to 3.5 μm. Capacitors based on CNETMS films exhibit extractable energy densities of 7 J/cm(3) at 300 V/μm, as determined by charge-discharge and polarization-electric field measurements, as well as an energy extraction efficiency of ~91%. The large extractable energy resulting from the linear dielectric polarization behavior suggests that CNETMS films are promising sol-gel materials for pulsed power applications. PMID:23427818

  3. Focusing dynamics of high-energy density, laser-driven ion beams.

    PubMed

    Chen, S N; d'Humières, E; Lefebvre, E; Romagnani, L; Toncian, T; Antici, P; Audebert, P; Brambrink, E; Cecchetti, C A; Kudyakov, T; Pipahl, A; Sentoku, Y; Borghesi, M; Willi, O; Fuchs, J

    2012-02-01

    The dynamics of the focusing of laser-driven ion beams produced from concave solid targets was studied. Most of the ion beam energy is observed to converge at the center of the cylindrical targets with a spot diameter of 30  μm, which can be very beneficial for applications requiring high beam energy densities. Also, unbalanced laser irradiation does not compromise the focusability of the beam. However, significant filamentation occurs during the focusing, potentially limiting the localization of the energy deposition region by these beams at focus. These effects could impact the applicability of such high-energy density beams for applications, e.g., in proton-driven fast ignition. PMID:22400936

  4. Effects of the density of collision cascades: Separating contributions from dynamic annealing and energy spikes

    SciTech Connect

    Titov, A I; Karaseov, P A; Azarov, A Y; Kucheyev, S O

    2008-08-13

    We present a quantitative model for the efficiency of the molecular effect in damage buildup in semiconductors. Our model takes into account only one mechanism of the cascade density dependence: nonlinear energy spikes. In our three-dimensional analysis, the volume of each individual collision cascade is divided into small cubic cells, and the number of cells that have an average density of displacements above some threshold value is calculated. We assume that such cells experience a catastrophic crystalline-to-amorphous phase transition, while defects in the cells with lower displacement densities have perfect annihilation. For the two limiting cases of heavy (500 keV/atom {sup 209}Bi) and light (40 keV/atom {sup 14}N) ion bombardment of Si, theory predictions are in good agreement with experimental data for a threshold displacement density of 4.5 at.%. For intermediate density cascades produced by small 2.1 keV/amu PF{sub n} clusters, we show that dynamic annealing processes entirely dominate cascade density effects for PF{sub 2} ions, while energy spikes begin contributing in the case of PF{sub 4} cluster bombardment.

  5. Determination of Energy Independent Neutron Densities using Dirac Phenomenology based on the RIA

    NASA Astrophysics Data System (ADS)

    Clark, B. C.; Kerr, L. J.; Hama, S.; Mercer, R. L.

    2002-04-01

    A new method for extracting neutron densities from intermediate energy elastic proton-nucleus scattering observables using a global Dirac phenomenological (DP) approach based on the Relativistic Impulse Approximation (RIA) is presented. (B. C. Clark, et al.) BAPS Vol 46, No. 7 pg.139, 2001. We have considered data sets for ^40Ca, ^48Ca and ^208Pb and energies from 500 MeV to 1040 MeV. The global fits are successful in reproducing the data and in predicting data sets not included in the analysis. Using this global DP approach we have obtained energy independent neutron densities. The vector point proton density distribution, ρ^p_v, is determined from the empirical charge density after unfolding the proton form factor. The other densities, ρ^n_v, ρ^p_s, ρ^n_s, are parameterized using the cosh form given in our paper on global DP optical potentials.(E. D. Cooper, et al.) Phys Rev. 47C, pg. 297, 1993 Neutron skin thicknesses extracted using the global analysis are compared to predictions from theoretical models.

  6. New approaches for the calibration of exchange-energy densities in local hybrid functionals.

    PubMed

    Maier, Toni M; Haasler, Matthias; Arbuznikov, Alexei V; Kaupp, Martin

    2016-08-21

    The ambiguity of exchange-energy densities is a fundamental challenge for the development of local hybrid functionals, or of other functionals based on a local mixing of exchange-energy densities. In this work, a systematic construction of semi-local calibration functions (CFs) for adjusting the exchange-energy densities in local hybrid functionals is provided, which directly links a given CF to an underlying semi-local exchange functional, as well as to the second-order gradient expansion of the exchange hole. Using successive steps of integration by parts allows the derivation of correction terms of increasing order, resulting in more and more complicated but also more flexible CFs. We derive explicit first- and second-order CFs (pig1 and pig2) based on B88 generalized-gradient approximation (GGA) exchange, and a first-order CF (tpig1) based on τ-dependent B98 meta-GGA exchange. We combine these CFs with different long-range damping functions and evaluate them for calibration of LDA, B88 GGA, and TPSS meta-GGA exchange-energy densities. Based on a minimization of unphysical nondynamical correlation contributions in three noble-gas dimer potential-energy curves, free parameters in the CFs are optimized, and performance of various approaches in the calibration of different exchange-energy densities is compared. Most notably, the second-order pig2 CF provides the largest flexibility with respect to the diffuseness of the damping function. This suggests that higher-order CFs based on the present integration-by-parts scheme may be particularly suitable for the flexible construction of local hybrid functionals. PMID:27080804

  7. Study of Au/TiO2 interface structure using Energy Density Method

    NASA Astrophysics Data System (ADS)

    Yu, Min; Trinkle, Dallas R.; Martin, Richard M.

    2010-03-01

    We propose a way to decompose the total energy in a material into the contribution associated with each of the atoms, using the first principles energy density formalism[1]. Although the energy density function is non-unique up to a gauge transformation, we show that unique defect energies can be found by defining volumes for each atoms using the Bader charge analysis[2]. The methods are applied to gold nanoclusters supported on rutile titanium dioxide, which are commonly used as catalysts for chemical reactions. The variation in structure and chemistry of the interface may affect catalytic acticity. In this work, we study four model interfaces; Au(111)//TiO2(110) and Au(100)//TiO2(110), with and without bridging oxygen. Calculations are performed using the projector augmented wave method implemented in the Vienna ab initio simulation package[3], and the energy density method computes the interfacial energies to determine the equlibrium interfacial structure. [1]Phys. Rev. B 45, 6074 (1992) [2]Comput. Mater. Sci. 36, 254 (2006) [3]Phys. Rev. B 59, 1758 (1999)

  8. Effect of the energy density of a solid-liquid meal on gastric emptying and satiety.

    PubMed

    Carbonnel, F; Lémann, M; Rambaud, J C; Mundler, O; Jian, R

    1994-09-01

    The effect of the energy density of a meal on gastric emptying and satiety was assessed in nine volunteers. They ingested, in randomized order, a diluted (2671 kJ/L, 950 mL) and a concentrated (7452 kJ/L, 350 mL) test meal of 2500 kJ each (80% as solids). Half-emptying times of solids and liquids were not significantly different for the diluted and concentrated meal (solids: 145 +/- 18 and 156 +/- 16 min, respectively; liquids: 76 +/- 10 and 84 +/- 10 min, respectively), and consequently, pyloric outputs of energy were identical. Neither the intensity and duration of satiety, nor the amount of energy ingested, ad libitum, 6 h after the test meal, were significantly affected by energy density of the food ingested. Both the intensity and duration of satiety correlated significantly with the gastric emptying time for solids (r = 0.60 and 0.67, respectively, P < 0.01). These results show that satiety depends on gastric emptying of energy and is not affected by the energy density of food intake. PMID:8074058

  9. Approach to kinetic energy density functionals: Nonlocal terms with the structure of the von Weizsaecker functional

    SciTech Connect

    Garcia-Aldea, David; Alvarellos, J. E.

    2008-02-15

    We propose a kinetic energy density functional scheme with nonlocal terms based on the von Weizsaecker functional, instead of the more traditional approach where the nonlocal terms have the structure of the Thomas-Fermi functional. The proposed functionals recover the exact kinetic energy and reproduce the linear response function of homogeneous electron systems. In order to assess their quality, we have tested the total kinetic energies as well as the kinetic energy density for atoms. The results show that these nonlocal functionals give as good results as the most sophisticated functionals in the literature. The proposed scheme for constructing the functionals means a step ahead in the field of fully nonlocal kinetic energy functionals, because they are capable of giving better local behavior than the semilocal functionals, yielding at the same time accurate results for total kinetic energies. Moreover, the functionals enjoy the possibility of being evaluated as a single integral in momentum space if an adequate reference density is defined, and then quasilinear scaling for the computational cost can be achieved.

  10. Dependence of Electron Density on Fermi Energy in N-Type Gallium Antimonide

    PubMed Central

    Bennett, Herbert S.; Hung, Howard

    2003-01-01

    The majority electron density as a function of the Fermi energy is calculated in zinc blende, n-type GaSb for donor densities between 1016 cm−3 and 1019 cm−3. These calculations solve the charge neutrality equation self-consistently for a four-band model (three conduction sub-bands at Γ, L, and X and one equivalent valence band at Γ) of GaSb. Our calculations assume parabolic densities of states and thus do not treat the density-of-states modifications due to high concentrations of dopants, many body effects, and non-parabolicity of the bands. Even with these assumptions, the results are important for interpreting optical measurements such as Raman measurements that are proposed as a nondestructive method for wafer acceptance tests.

  11. Why Density-Gradient Corrections Improve Atomization Energies and Barrier Heights

    NASA Astrophysics Data System (ADS)

    Perdew, John P.; Ernzerhof, Matthias; Zupan, Ales; Burke, Kieron

    While the Hartree-Fock (HF) approximation typically underestimates the strength of the chemical bond, the local spin density (LSD) approximation overestimates it. Thus LSD overbinds atoms in molecules, and underestimates the heights of energy barriers when the transition state is more highly bonded than the initial state. Generalized gradient approximations (GGA's), which incorporate density-gradient corrections to LSD, improve the agreement between calculated and measured energetics. This has been previously understood as a consequence of the fact that gradient corrections favor density inhomogeneity, which increases when a bond is stretched or broken. We show that gradient corrections also favor high density, which increases when a bond is compressed or formed, but that the inhomogeneity effect usually prevails. To quantify the discussion, we present a thermodynamic-like inequality which is satisfied when gradient corrections favor a process.

  12. Compressed Liquid Densities and Helmholtz Energy Equation of State for Fluoroethane (R161)

    NASA Astrophysics Data System (ADS)

    Qi, Haiyan; Fang, Dan; Gao, Kehui; Meng, Xianyang; Wu, Jiangtao

    2016-06-01

    In this study, compressed liquid densities of Fluoroethane (R161, CAS No. 353-36-6) were measured using a high-pressure vibrating-tube densimeter over the temperature range from (283 to 363) K with pressures up to 100 MPa. A Helmholtz energy equation of state for R161 was developed from these density measurements and other experimental thermodynamic property data from the literature. The formulation is valid for temperatures from the triple point temperature of 130 K to 420 K with pressures up to 100 MPa. The approximate uncertainties of properties calculated with the new equation of state are estimated to be 0.25 % in density, 0.2 % in saturated liquid density between 230 K and 320 K, and 0.2 % in vapor pressure below 350 K. Deviations in the critical region are higher for all properties. The extrapolation behavior of the new formulation at high temperatures and high pressures is reasonable.

  13. Dynamical features of the plasma-sheet ion composition, density, and energy

    NASA Technical Reports Server (NTRS)

    Lennartsson, W.

    1987-01-01

    The effects of changes in solar and geomagnetic activity on the major plasma-sheet ions are investigated on the basis of a statistical analysis of 1500 h of data obtained at distances 10-23 earth radii and energy/charge ratios 0.1-16 keV/e by the ISEE-1 energetic-ion mass spectrometer. The results are presented in extensive graphs and discussed in detail. It is found that substorm activity is accompanied by a significant decrease in the density of solar-origin H(+) ions, a sharp increase in the energy per nucleon of both H(+) and He(+) ions, and an increase in the density of terrestrial O(+) ions. A factor-of-three increase in the overall O(+) density over the observation period is attributed to an increase in the solar EUV flux.

  14. Experimental design to generate strong shear layers in a high-energy-density plasma

    NASA Astrophysics Data System (ADS)

    Harding, E. C.; Drake, R. P.; Aglitskiy, Y.; Gillespie, R. S.; Grosskopf, M. J.; Weaver, J. L.; Velikovich, A. L.; Visco, A.; Ditmar, J. R.

    2010-06-01

    The development of a new experimental system for generating a strong shear flow in a high-energy-density plasma is described in detail. The targets were designed with the goal of producing a diagnosable Kelvin-Helmholtz (KH) instability, which plays an important role in the transition turbulence but remains relatively unexplored in the high-energy-density regime. To generate the shear flow the Nike laser was used to drive a flow of Al plasma over a low-density foam surface with an initial perturbation. The interaction of the Al and foam was captured with a spherical crystal imager using 1.86 keV X-rays. The selection of the individual targets components is discussed and results are presented.

  15. Energy density in small systems equal to the one in heavy-ion collisions

    NASA Astrophysics Data System (ADS)

    Paić, G.; Cuautle, E.

    2016-07-01

    The recent developments in the study of quark-gluon matter at high densities have shown that there are many similarities between the behavior of the observables in light and heavy systems, especially when the light systems are observed at high multiplicities. Contrary to what was previously thought, the small systems do exhibit collective effects that could indicate that small droplets of strongly interacting quark-gluon plasma are possible. The results infer that the energy densities can be computed in light systems in the same way as in heavy systems and hence, the energy density should be considered when comparing systems with different sizes. We review some of the aspects as well as the existing main models and the way to disentangle them using experimental data.

  16. Stochastic thermodynamics of fluctuating density fields: Non-equilibrium free energy differences under coarse-graining

    SciTech Connect

    Leonard, T.; Lander, B.; Seifert, U.; Speck, T.

    2013-11-28

    We discuss the stochastic thermodynamics of systems that are described by a time-dependent density field, for example, simple liquids and colloidal suspensions. For a time-dependent change of external parameters, we show that the Jarzynski relation connecting work with the change of free energy holds if the time evolution of the density follows the Kawasaki-Dean equation. Specifically, we study the work distributions for the compression and expansion of a two-dimensional colloidal model suspension implementing a practical coarse-graining scheme of the microscopic particle positions. We demonstrate that even if coarse-grained dynamics and density functional do not match, the fluctuation relations for the work still hold albeit for a different, apparent, change of free energy.

  17. Stochastic thermodynamics of fluctuating density fields: Non-equilibrium free energy differences under coarse-graining

    NASA Astrophysics Data System (ADS)

    Leonard, T.; Lander, B.; Seifert, U.; Speck, T.

    2013-11-01

    We discuss the stochastic thermodynamics of systems that are described by a time-dependent density field, for example, simple liquids and colloidal suspensions. For a time-dependent change of external parameters, we show that the Jarzynski relation connecting work with the change of free energy holds if the time evolution of the density follows the Kawasaki-Dean equation. Specifically, we study the work distributions for the compression and expansion of a two-dimensional colloidal model suspension implementing a practical coarse-graining scheme of the microscopic particle positions. We demonstrate that even if coarse-grained dynamics and density functional do not match, the fluctuation relations for the work still hold albeit for a different, apparent, change of free energy.

  18. A novel high-density power energy harvesting methodology for transmission line online monitoring devices

    NASA Astrophysics Data System (ADS)

    Liu, Yadong; Xie, Xiaolei; Hu, Yue; Qian, Yong; Sheng, Gehao; Jiang, Xiuchen; Liu, Yilu

    2016-07-01

    This paper presents a novel energy-harvesting model which takes the primary current, secondary turns, dimension, the magnitude of magnetic flux density B, and the core loss resistance into consideration systematically. The relationship among the potential maximum output power, the dimension of energy harvesting coil (EHC), the load type of EHC, and the secondary turns is predicted by theoretical analysis and further verified by experiments. A high power density harvester is also developed and tested. It is shown that the power density of this novel harvester is 0.7 mW/g at 10 A, which is more than 2 times powerful than the traditional ones. Hence, it could lighten the half weight of the harvester at the same conditions.

  19. ENERGY-DISPERSIVE, X-RAY REFLECTIVITY DENSITY MEASUREMENTS OF POROUS SIO2 XEROGELS

    EPA Science Inventory

    X-ray reflectivity has been used to nondestructively measure the density of thin, porous, SiO2-based xerogels. Critical angle, defined by total external reflection, was measured for multiple x-ray energies to correct for sample misalignment error in me determination of the densit...

  20. Density dependence of the symmetry energy from neutron skin thickness in finite nuclei

    SciTech Connect

    Vinas, X.; Centelles, M.; Roca-Maza, X.; Warda, M.

    2012-10-20

    The density dependence of the symmetry energy, characterized by the parameter L, is studied using information provided by the neutron skin thickness in finite nuclei. An estimate of L is obtained from experimental data of antiprotonic atoms. We also discuss the ability of parity violating electron scatering to obtain information about the neutron skin thickness in {sup 208}Pb.

  1. The Potential Energy Density in Transverse String Waves Depends Critically on Longitudinal Motion

    ERIC Educational Resources Information Center

    Rowland, David R.

    2011-01-01

    The question of the correct formula for the potential energy density in transverse waves on a taut string continues to attract attention (e.g. Burko 2010 "Eur. J. Phys." 31 L71), and at least three different formulae can be found in the literature, with the classic text by Morse and Feshbach ("Methods of Theoretical Physics" pp 126-127) stating…

  2. A Fiber Supercapacitor with High Energy Density Based on Hollow Graphene/Conducting Polymer Fiber Electrode.

    PubMed

    Qu, Guoxing; Cheng, Jianli; Li, Xiaodong; Yuan, Demao; Chen, Peining; Chen, Xuli; Wang, Bin; Peng, Huisheng

    2016-05-01

    A hollow graphene/conducting polymer composite fiber is created with high mechanical and electronic properties and used to fabricate novel fiber-shaped supercapacitors that display high energy densities and long life stability. The fiber supercapacitors can be woven into flexible powering textiles that are particularly promising for portable and wearable electronic devices. PMID:27001216

  3. Energy density, nutrient adequacy and food prices in the Lower Mississippi Delta

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The purpose was to assess the relationship of food cost with: 1) energy density (ED) and 2) nutrient adequacy [naturally nutrient rich (NNR) score] for 102 foods inventoried in a sample of 225 supermarkets, small/medium grocery stores, and convenience stores in the 36-county region of the Lower Miss...

  4. Electromagnetic energy density manipulation and enhancement in a relativistic plasma: the role of relativistic nonlinearities

    SciTech Connect

    Pegoraro, F.

    2009-11-10

    A tutorial presentation is given describing the nature and the effects of relativistic nonlinearities in a plasma and indicating how they can be exploited in order to manipulate and enhance locally the energy density of the electromagnetic fields. The mathematical formulation and the examples presented are chosen from results available in the scientific literature.

  5. Threshold Energy Density of Lower Hybrid Waves in the Freja Experiment

    SciTech Connect

    Popel, S. I.

    2001-05-15

    Data from the Freja satellite experiment on the lower hybrid turbulence in the Earth's magnetosphere are analyzed. It is shown that the observed threshold energy density of lower hybrid waves required for the excitation of localized wave packets is in good agreement with theoretical predictions.

  6. Technological development of cylindrical and flat shaped high energy density capacitors. [using polymeric films

    NASA Technical Reports Server (NTRS)

    Zelik, J. A.; Parker, R. D.

    1977-01-01

    Cylindrical wound metallized film capacitors rated 2 micron F 500 VDC that had an energy density greater than 0.3 J/g, and flat flexible metallized film capacitors rated at 2 micron F 500 VDC that had an energy density greater than 0.1 J/g were developed. Polysulfone, polycarbonate, and polyvinylidene fluoride (PVF2) were investigated as dielectrics for the cylindrical units. PVF2 in 6.0 micron m thickness was employed in the final components of both types. Capacitance and dissipation factor measurements were made over the range 25 C to 100 C, and 10 Hz to 10 kHz. No pre-life-test burning was performed, and six of ten cylindrical units survived a 2500 hour AC plus DC lift test. Three of the four failures were infant mortality. All but two of the flat components survived 400 hours. Finished energy densities were 0.104 J/g at 500 V and 0.200 J/g at 700 V, the energy density being limited by the availability of thin PVF2 films.

  7. Shock waves in a Z-pinch and the formation of high energy density plasma

    SciTech Connect

    Rahman, H. U.; Wessel, F. J.; Ney, P.; Presura, R.; Ellahi, Rahmat; Shukla, P. K.

    2012-12-15

    A Z-pinch liner, imploding onto a target plasma, evolves in a step-wise manner, producing a stable, magneto-inertial, high-energy-density plasma compression. The typical configuration is a cylindrical, high-atomic-number liner imploding onto a low-atomic-number target. The parameters for a terawatt-class machine (e.g., Zebra at the University of Nevada, Reno, Nevada Terawatt Facility) have been simulated. The 2-1/2 D MHD code, MACH2, was used to study this configuration. The requirements are for an initial radius of a few mm for stable implosion; the material densities properly distributed, so that the target is effectively heated initially by shock heating and finally by adiabatic compression; and the liner's thickness adjusted to promote radial current transport and subsequent current amplification in the target. Since the shock velocity is smaller in the liner, than in the target, a stable-shock forms at the interface, allowing the central load to accelerate magnetically and inertially, producing a magneto-inertial implosion and high-energy density plasma. Comparing the implosion dynamics of a low-Z target with those of a high-Z target demonstrates the role of shock waves in terms of compression and heating. In the case of a high-Z target, the shock wave does not play a significant heating role. The shock waves carry current and transport the magnetic field, producing a high density on-axis, at relatively low temperature. Whereas, in the case of a low-Z target, the fast moving shock wave preheats the target during the initial implosion phase, and the later adiabatic compression further heats the target to very high energy density. As a result, the compression ratio required for heating the low-Z plasma to very high energy densities is greatly reduced.

  8. Publications of Proceedings for the RF 2005 7th Workshop on High Energy Density and High Power RF

    SciTech Connect

    Luhmann, Jr, N C

    2006-01-01

    The University of California, Davis hosted the High Energy Density and High Power RF 7th Workshop on High Energy Density and High Power RF in Kalamata, Greece, 13-17 June, 2005. The Proceedings cost was supported by these funds from the U.S. Department of Energy. The Proceedings was published through the American Institute of Physics.

  9. The Γ-Limit of the Two-Dimensional Ohta-Kawasaki Energy. I. Droplet Density

    NASA Astrophysics Data System (ADS)

    Goldman, Dorian; Muratov, Cyrill B.; Serfaty, Sylvia

    2013-11-01

    This is the first in a series of two papers in which we derive a Γ-expansion for a two-dimensional non-local Ginzburg-Landau energy with Coulomb repulsion, also known as the Ohta-Kawasaki model, in connection with diblock copolymer systems. In that model, two phases appear, which interact via a nonlocal Coulomb type energy. We focus on the regime where one of the phases has very small volume fraction, thus creating small "droplets" of the minority phase in a "sea" of the majority phase. In this paper we show that an appropriate setting for Γ-convergence in the considered parameter regime is via weak convergence of the suitably normalized charge density in the sense of measures. We prove that, after a suitable rescaling, the Ohta-Kawasaki energy functional Γ-converges to a quadratic energy functional of the limit charge density generated by the screened Coulomb kernel. A consequence of our results is that minimizers (or almost minimizers) of the energy have droplets which are almost all asymptotically round, have the same radius and are uniformly distributed in the domain. The proof relies mainly on the analysis of the sharp interface version of the energy, with the connection to the original diffuse interface model obtained via matching upper and lower bounds for the energy. We thus also obtain an asymptotic characterization of the energy minimizers in the diffuse interface model.

  10. Charge Energy Transport in Hopping Systems with Rapidly Decreasing Density of States

    NASA Astrophysics Data System (ADS)

    Mendels, Dan; Organic Electronics Group Technion Team

    2014-03-01

    An accurate description of the carrier hopping topology in the energy domain of hopping systems incorporating a rapidly decreasing density of states and the subsequent energetic position of these systems' so called effective conduction band is crucial for rationalizing and quantifying these systems' thermo-electric properties, doping related phenomena and carrier gradient effects such as the emergence of the General Einstein Relation under degenerate conditions. Additionally, as will be shown, the 'mobile' carriers propagating through the system can have excess energies reaching 0.3eV above the system quasi-Fermi energy. Hence, since these mobile carriers are most prone to reach systems interfaces and interact with oppositely charged carriers, their excess energy should be considered in determining the efficiencies of energy dependent processes such as carrier recombination and exciton dissociation. In light of the stated motivations, a comprehensive numerical and analytical study of the topology of hopping in the energetic density of such systems (i.e. the statistics regarding which energy values carriers visit most and in what manner) was implemented and the main statistical features of the hopping process that determine the position in energy of the system's effective conduction band were distilled. The obtained results also help shed light on yet to be elucidated discrepancies between predictions given by the widely employed transport energy concept and Monte Carlo simulations.

  11. Quantification of breast density with dual energy mammography: A simulation study

    SciTech Connect

    Ducote, Justin L.; Molloi, Sabee

    2008-12-15

    Breast density, the percentage of glandular breast tissue, has been identified as an important yet underutilized risk factor in the development of breast cancer. A quantitative method to measure breast density with dual energy imaging was investigated using a computer simulation model. Two configurations to measure breast density were evaluated: the usage of monoenergetic beams and an ideal detector, and the usage of polyenergetic beams with spectra from a tungsten anode x-ray tube with a detector modeled after a digital mammography system. The simulation model calculated the mean glandular dose necessary to quantify the variability of breast density to within (1/3)%. The breast was modeled as a semicircle 10 cm in radius with equal homogenous thicknesses of adipose and glandular tissues. Breast thicknesses were considered in the range of 2-10 cm and energies in the range of 10-150 keV for the two monoenergetic beams, and 20-150 kVp for spectra with a tungsten anode x-ray tube. For a 4.2 cm breast thickness, the required mean glandular doses were 0.183 {mu}Gy for two monoenergetic beams at 19 and 71 keV, and 9.85 {mu}Gy for two polyenergetic spectra from a tungsten anode at 32 and 96 kVp with beam filtrations of 50 {mu}m Rh and 300 {mu}m Cu for the low and high energy beams, respectively. The results suggest that for either configuration, breast density can be precisely measured with dual energy imaging requiring only a small amount of additional dose to the breast. The possibility of using a standard screening mammogram as the low energy image is also discussed.

  12. Silicon-Nanowire Based Lithium Ion Batteries for Vehicles With Double the Energy Density

    SciTech Connect

    Stefan, Ionel; Cohen, Yehonathan

    2015-03-31

    Amprius researched and developed silicon nanowire anodes. Amprius then built and delivered high-energy lithium-ion cells that met the project’s specific energy goal and exceeded the project’s energy density goal. But Amprius’ cells did not meet the project’s cycle life goal, suggesting additional manufacturing process development is required. With DOE support, Amprius developed a new anode material, silicon, and a new anode structure, nanowire. During the project, Amprius also began to develop a new multi-step manufacturing process that does not involve traditional anode production processes (e.g. mixing, drying and calendaring).

  13. Maps of the little bangs through energy density and temperature fluctuations

    NASA Astrophysics Data System (ADS)

    Basu, Sumit; Chatterjee, Rupa; Nandi, Basanta K.; Nayak, Tapan K.

    2016-01-01

    Heavy-ion collisions at ultra-relativistic energies are often referred to as little bangs. We propose for the first time to map the heavy-ion collisions at ultra-relativistic energies, similar to the maps of the cosmic microwave background radiation, using fluctuations of energy density and temperature in small phase space bins. We study the evolution of fluctuations at each stage of the collision using an event-by-event hydrodynamic framework. We demonstrate the feasibility of making fluctuation maps from experimental data and its usefulness in extracting considerable information regarding the early stages of the collision and its evolution.

  14. Neural network approach to quantum-chemistry data: Accurate prediction of density functional theory energies

    NASA Astrophysics Data System (ADS)

    Balabin, Roman M.; Lomakina, Ekaterina I.

    2009-08-01

    Artificial neural network (ANN) approach has been applied to estimate the density functional theory (DFT) energy with large basis set using lower-level energy values and molecular descriptors. A total of 208 different molecules were used for the ANN training, cross validation, and testing by applying BLYP, B3LYP, and BMK density functionals. Hartree-Fock results were reported for comparison. Furthermore, constitutional molecular descriptor (CD) and quantum-chemical molecular descriptor (QD) were used for building the calibration model. The neural network structure optimization, leading to four to five hidden neurons, was also carried out. The usage of several low-level energy values was found to greatly reduce the prediction error. An expected error, mean absolute deviation, for ANN approximation to DFT energies was 0.6±0.2 kcal mol-1. In addition, the comparison of the different density functionals with the basis sets and the comparison of multiple linear regression results were also provided. The CDs were found to overcome limitation of the QD. Furthermore, the effective ANN model for DFT/6-311G(3df,3pd) and DFT/6-311G(2df,2pd) energy estimation was developed, and the benchmark results were provided.

  15. Advanced intermediate temperature sodium-nickel chloride batteries with ultra-high energy density

    NASA Astrophysics Data System (ADS)

    Li, Guosheng; Lu, Xiaochuan; Kim, Jin Y.; Meinhardt, Kerry D.; Chang, Hee Jung; Canfield, Nathan L.; Sprenkle, Vincent L.

    2016-02-01

    Sodium-metal halide batteries have been considered as one of the more attractive technologies for stationary electrical energy storage, however, they are not used for broader applications despite their relatively well-known redox system. One of the roadblocks hindering market penetration is the high-operating temperature. Here we demonstrate that planar sodium-nickel chloride batteries can be operated at an intermediate temperature of 190 °C with ultra-high energy density. A specific energy density of 350 Wh kg-1, higher than that of conventional tubular sodium-nickel chloride batteries (280 °C), is obtained for planar sodium-nickel chloride batteries operated at 190 °C over a long-term cell test (1,000 cycles), and it attributed to the slower particle growth of the cathode materials at the lower operating temperature. Results reported here demonstrate that planar sodium-nickel chloride batteries operated at an intermediate temperature could greatly benefit this traditional energy storage technology by improving battery energy density, cycle life and reducing material costs.

  16. Advanced intermediate temperature sodium-nickel chloride batteries with ultra-high energy density.

    PubMed

    Li, Guosheng; Lu, Xiaochuan; Kim, Jin Y; Meinhardt, Kerry D; Chang, Hee Jung; Canfield, Nathan L; Sprenkle, Vincent L

    2016-01-01

    Sodium-metal halide batteries have been considered as one of the more attractive technologies for stationary electrical energy storage, however, they are not used for broader applications despite their relatively well-known redox system. One of the roadblocks hindering market penetration is the high-operating temperature. Here we demonstrate that planar sodium-nickel chloride batteries can be operated at an intermediate temperature of 190 °C with ultra-high energy density. A specific energy density of 350 Wh kg(-1), higher than that of conventional tubular sodium-nickel chloride batteries (280 °C), is obtained for planar sodium-nickel chloride batteries operated at 190 °C over a long-term cell test (1,000 cycles), and it attributed to the slower particle growth of the cathode materials at the lower operating temperature. Results reported here demonstrate that planar sodium-nickel chloride batteries operated at an intermediate temperature could greatly benefit this traditional energy storage technology by improving battery energy density, cycle life and reducing material costs. PMID:26864635

  17. Advanced intermediate temperature sodium–nickel chloride batteries with ultra-high energy density

    PubMed Central

    Li, Guosheng; Lu, Xiaochuan; Kim, Jin Y.; Meinhardt, Kerry D.; Chang, Hee Jung; Canfield, Nathan L.; Sprenkle, Vincent L.

    2016-01-01

    Sodium-metal halide batteries have been considered as one of the more attractive technologies for stationary electrical energy storage, however, they are not used for broader applications despite their relatively well-known redox system. One of the roadblocks hindering market penetration is the high-operating temperature. Here we demonstrate that planar sodium–nickel chloride batteries can be operated at an intermediate temperature of 190 °C with ultra-high energy density. A specific energy density of 350 Wh kg−1, higher than that of conventional tubular sodium–nickel chloride batteries (280 °C), is obtained for planar sodium–nickel chloride batteries operated at 190 °C over a long-term cell test (1,000 cycles), and it attributed to the slower particle growth of the cathode materials at the lower operating temperature. Results reported here demonstrate that planar sodium–nickel chloride batteries operated at an intermediate temperature could greatly benefit this traditional energy storage technology by improving battery energy density, cycle life and reducing material costs. PMID:26864635

  18. Thermodynamic, energy efficiency, and power density analysis of reverse electrodialysis power generation with natural salinity gradients.

    PubMed

    Yip, Ngai Yin; Vermaas, David A; Nijmeijer, Kitty; Elimelech, Menachem

    2014-05-01

    Reverse electrodialysis (RED) can harness the Gibbs free energy of mixing when fresh river water flows into the sea for sustainable power generation. In this study, we carry out a thermodynamic and energy efficiency analysis of RED power generation, and assess the membrane power density. First, we present a reversible thermodynamic model for RED and verify that the theoretical maximum extractable work in a reversible RED process is identical to the Gibbs free energy of mixing. Work extraction in an irreversible process with maximized power density using a constant-resistance load is then examined to assess the energy conversion efficiency and power density. With equal volumes of seawater and river water, energy conversion efficiency of ∼ 33-44% can be obtained in RED, while the rest is lost through dissipation in the internal resistance of the ion-exchange membrane stack. We show that imperfections in the selectivity of typical ion exchange membranes (namely, co-ion transport, osmosis, and electro-osmosis) can detrimentally lower efficiency by up to 26%, with co-ion leakage being the dominant effect. Further inspection of the power density profile during RED revealed inherent ineffectiveness toward the end of the process. By judicious early discontinuation of the controlled mixing process, the overall power density performance can be considerably enhanced by up to 7-fold, without significant compromise to the energy efficiency. Additionally, membrane resistance was found to be an important factor in determining the power densities attainable. Lastly, the performance of an RED stack was examined for different membrane conductivities and intermembrane distances simulating high performance membranes and stack design. By thoughtful selection of the operating parameters, an efficiency of ∼ 37% and an overall gross power density of 3.5 W/m(2) represent the maximum performance that can potentially be achieved in a seawater-river water RED system with low

  19. High energy density micro-fiber based nickel electrode for aerospace batteries

    NASA Technical Reports Server (NTRS)

    Francisco, Jennifer; Chiappetti, Dennis; Coates, Dwaine

    1996-01-01

    The nickel electrode is the specific energy limiting component in battery systems such as nickel-hydrogen, nickel-metal hydride and nickel-zinc. Lightweight, high energy density nickel electrodes have been developed which deliver in excess of 180 mAh/g at the one-hour discharge rate. These electrodes are based on a highly porous, nickel micro-fiber (less than 10 micron diameter) substrate, electrochemically impregnated with nickel-hydroxide active material. Electrodes are being tested both as a flooded half-cell and in full nickel-hydrogen and nickel-metal hydride cells. The electrode technology developed is applicable to commercial nickel-based batteries for applications such as electric vehicles, cellular telephones and laptop computers and for low-cost, high energy density military and aerospace applications.

  20. Method for controlling energy density for reliable pulsed laser deposition of thin films

    SciTech Connect

    Dowden, P. C. E-mail: qxjia@lanl.gov; Bi, Z.; Jia, Q. X. E-mail: qxjia@lanl.gov

    2014-02-15

    We have established a methodology to stabilize the laser energy density on a target surface in pulsed laser deposition of thin films. To control the focused laser spot on a target, we have imaged a defined aperture in the beamline (so called image-focus) instead of focusing the beam on a target based on a simple “lens-focus.” To control the laser energy density on a target, we have introduced a continuously variable attenuator between the output of the laser and the imaged aperture to manipulate the energy to a desired level by running the laser in a “constant voltage” mode to eliminate changes in the lasers’ beam dimensions. This methodology leads to much better controllability/reproducibility for reliable pulsed laser deposition of high performance electronic thin films.

  1. The Dawn of a New Era for High Energy Density Physics

    SciTech Connect

    Moses, E; McCrory, R; Meyerhofer, D; Keane, C

    2009-02-26

    The field of High Energy Density (HED) physics is on the verge of a revolutionary event - the achievement of fusion ignition in the laboratory. New laser facilities, the OMEGA Extended Performance (EP) laser at the University of Rochester and the National Ignition Facility (NIF) at Lawrence Livermore National Laboratory, greatly extend the range of high energy density (HED) plasma conditions (including ignition) accessible in the laboratory. These conditions are among the most extreme obtainable, with pressures in excess of {approx}1,000,000 atmospheres. Experiments at these facilities will elucidate fundamental new science in astrophysics, materials science, laser-matter interactions, and other areas. The demonstration of fusion ignition will be the culmination of decades of research, and for the first time, will open the burning plasma regime to laboratory exploration. Ignition will spur the development of advanced options for clean, environmentally sustainable energy.

  2. High energy density micro-fiber based nickel electrode for aerospace batteries

    SciTech Connect

    Francisco, J.; Chiappetti, D.; Coates, D.

    1996-11-01

    The nickel electrode is the specific energy limiting component in battery systems such as nickel-hydrogen, nickel-metal hydride and nickel-zinc. Lightweight, high energy density nickel electrodes have been developed which deliver in excess of 180 mAh/g at the one-hour discharge rate. These electrodes are based on a highly porous, nickel micro-fiber (< 10 micron diameter) substrate, electrochemically impregnated with nickel-hydroxide active material. Electrodes are being tested both as a flooded half-cell and in full nickel-hydrogen and nickel-metal hydride cells. The electrode technology developed is applicable to commercial nickel-based batteries for applications such as electric vehicles, cellular telephones and laptop computers and for low-cost, high energy density military and aerospace applications.

  3. High energy density micro-fiber based nickel electrode for aerospace batteries

    SciTech Connect

    Francisco, J.; Chiappetti, D.; Coates, D.

    1996-02-01

    The nickel electrode is the specific energy limiting component in battery systems such as nickel-hydrogen, nickel-metal hydride and nickel-zinc. Lightweight, high energy density nickel electrodes have been developed which deliver in excess of 180 mAh/g at the one-hour discharge rate. These electrodes are based on a highly porous, nickel micro-fiber (less than 10 micron diameter) substrate, electrochemically impregnated with nickel-hydroxide active material. Electrodes are being tested both as a flooded half-cell and in full nickel-hydrogen and nickel-metal hydride cells. The electrode technology developed is applicable to commercial nickel-based batteries for applications such as electric vehicles, cellular telephones and laptop computers and for low-cost, high energy density military and aerospace applications.

  4. Density of states of the XY model: An energy landscape approach

    NASA Astrophysics Data System (ADS)

    Nardini, Cesare; Nerattini, Rachele; Casetti, Lapo

    2015-02-01

    Among the stationary configurations of the Hamiltonian of a classical O(n) lattice spin model, a class can be identified which is in one-to-one correspondence with all the configurations of an Ising model defined on the same lattice and with the same interactions. Starting from this observation it has been recently proposed that the microcanonical density of states of an O(n) model could be written in terms of the density of states of the corresponding Ising model. Later, it has been shown that a relation of this kind holds exactly for two solvable models, the mean-field and the one-dimensional XY model, respectively. We apply the same strategy to derive explicit, albeit approximate, expressions for the density of states of the two-dimensional XY model with nearest-neighbor interactions on a square lattice. The caloric curve and the specific heat as a function of the energy density are calculated and compared against simulation data, yielding a good agreement over the entire energy density range.

  5. α MnMoO₄/graphene hybrid composite: high energy density supercapacitor electrode material.

    PubMed

    Ghosh, Debasis; Giri, Soumen; Moniruzzaman, Md; Basu, Tanya; Mandal, Manas; Das, Chapal Kumar

    2014-07-28

    A unique and cost effective hydrothermal procedure has been carried out for the synthesis of hexahedron shaped α MnMoO4 and its hybrid composite with graphene using three different weight percentages of graphene. Characterization techniques, such as XRD, Raman and FTIR analysis, established the phase and formation of the composite. The electrochemical characterization of the pseudocapacitive MnMoO4 and the MnMoO4/graphene composites in 1 M Na2SO4 displayed highest specific capacitances of 234 F g(-1) and 364 F g(-1), respectively at a current density of 2 A g(-1). Unlike many other pseudocapacitive electrode materials our prepared materials responded in a wide range of working potentials of (-)1 V to (+)1 V, which indeed resulted in a high energy density without substantial loss of power density. The highest energy densities of 130 Wh kg(-1) and 202.2 Wh kg(-1) were achieved, respectively for the MnMoO4 and the MnMoO4/graphene composite at a constant power delivery rate of 2000 W kg(-1). The synergistic effect of the graphene with the pseudocapacitive MnMoO4 caused an increased cycle stability of 88% specific capacitance retention after 1000 consecutive charge discharge cycles at 8 A g(-1) constant current density, which was higher than the virgin MnMoO4 with 84% specific capacitance retention. PMID:24921461

  6. Twin engineering for high critical current densities and twin boundary energy measurement in melt processed YBCO

    NASA Astrophysics Data System (ADS)

    Mei, Linfeng

    It has been proven that twin boundaries in YBa2Cu 3O7-delta (YBCO) are effective flux pinning centers. By increasing the twin density of a YBCO sample, it is possible to achieve a high critical current density (Jc). In this work, twin engineering for high critical current densities and strong flux pinning has been achieved in melt processed YBCO by increasing the annealing temperature up to 680°C. When the isothermal oxygenation temperature increases from 450°C to 680°C, the average twin boundary spacing of the samples decreases significantly, and its critical current density and flux pinning force are greatly increased. The prerequisites for twin boundary engineering for high critical current densities and strong flux pinning are also pointed out. For the first time, temperature dependent twin boundary energies (gammatw's) of melt processed YBCO are measured by the twin spacing method and the twin tip or shape method, and the geometrical factor alpha in the twin spacing method is estimated. As expected, the twin boundary energy of YBCO decreases with increasing temperature. In addition, the correlation between Jc and the concentrations of Y2BaCuO5 (211) and Samarium (Sm) in the melt-textured growth (MTG) YBCO has been studied, as well as the distributions of 211 and Sm in the MTG YBCO pellets. All our results can be applied towards microstructure tailoring for a high Jc and strong flux pinning in YBCO, especially in bulk YBCO samples.

  7. A coupled remote sensing and the Surface Energy Balance based algorithms to estimate actual evapotranspiration over the western and southern regions of Saudi Arabia

    NASA Astrophysics Data System (ADS)

    Mahmoud, Shereif H.; Alazba, A. A.

    2016-07-01

    In countries with absolute water scarcity such as the Kingdom of Saudi Arabia (KSA), large-scale actual evapotranspiration estimation is of great concern in water use practices. Herein, spatial and temporal distribution of actual evapotranspiration (AET) in the western and southern regions of KSA during 1992-2014 was estimated using the SEBAL model with field observations. Zonal statistics for each land use-cover type were also identified, in order to understand their effects on water consumption. In addition, daily and seasonal water consumption for major crops was computed. Results revealed a gradual increase in monthly AET values from January to April and subsequent decline from May to December. The maximum monthly AET values were observed for irrigated cropland in southwestern, central, and southeastern regions of Asir Province, central and southwestern regions of Al-Baha Province, central and the plains region of Jazan Province, southern portion of Makkah Province, and limited areas in the northern regions of Madinah Province. The annual AET ranged from 418.8 to 3442.3 mm yr-1. The normal distribution of mean annual AET values ranged from 717 to 1020 mm yr-1. Forty-two percent of the study area had an annual AET that ranged from 717 to 1020 mm yr-1. The second highest range of frequencies was concentrated around 1020-1322 mm yr-1, representing the majority of agricultural land. The consumptive water use of the different land cover types in study area indicated that irrigated cropland which occupied 14.6% of the study area had AET rates much higher than other land uses. Water bodies are the next highest, with forest and shrubland and sparse vegetation slightly lower, and very low AET rates from bare soil. Daily and seasonal water consumption of major cropping systems varied spatially depending on cropping practices and climatic conditions.

  8. A solvation-free-energy functional: a reference-modified density functional formulation.

    PubMed

    Sumi, Tomonari; Mitsutake, Ayori; Maruyama, Yutaka

    2015-07-01

    The three-dimensional reference interaction site model (3D-RISM) theory, which is one of the most applicable integral equation theories for molecular liquids, overestimates the absolute values of solvation-free-energy (SFE) for large solute molecules in water. To improve the free-energy density functional for the SFE of solute molecules, we propose a reference-modified density functional theory (RMDFT) that is a general theoretical approach to construct the free-energy density functional systematically. In the RMDFT formulation, hard-sphere (HS) fluids are introduced as the reference system instead of an ideal polyatomic molecular gas, which has been regarded as the appropriate reference system of the interaction-site-model density functional theory for polyatomic molecular fluids. We show that using RMDFT with a reference HS system can significantly improve the absolute values of the SFE for a set of neutral amino acid side-chain analogues as well as for 504 small organic molecules. PMID:26032201

  9. Microporous organic polymer-based lithium ion batteries with improved rate performance and energy density

    NASA Astrophysics Data System (ADS)

    Zhang, Chong; Yang, Xiao; Ren, Wenfeng; Wang, Yanhong; Su, Fabing; Jiang, Jia-Xing

    2016-06-01

    Microporous organic polymers with triphenylamine segments were employed as cathode materials for lithium ion batteries. YPTPA with the highest surface area exhibits a discharge plateau at ∼3.6 V vs. Li/Li+, an initial Coulombic efficiency of 96.8% at 50 mA g-1 and a discharge capacity of 105.7 mAh g-1 at 200 mA g-1. Compared to the homo-coupled polymer of OPTPA with relatively low surface area (66 m2 g-1), SPTPA and YPTPA with higher surface area (544 and 1557 m2 g-1, respectively) show enhanced rate performances and energy densities. YPTPA can deliver 97.6 mAh g-1 within less than 3 min at high rate of 2000 mA g-1 and the energy density of 334 Wh kg-1 under an ultrahigh power density of 6816 W kg-1, while OPTPA only presents 48.2 mAh g-1 at 2000 mA g-1 with an energy density of 155 Wh kg-1 under 6414 W kg-1. The great improvement in electrochemical properties of SPTPA and YPTPA demonstrates that increasing surface area of polymer cathodes by interweaving the redox-active units into microporous polymer skeleton is an efficient way to develop advanced polymer cathode materials with outstanding electrochemical performance.

  10. Investigation of efficient shock acceleration of ions using high energy lasers in low density targets

    NASA Astrophysics Data System (ADS)

    Antici, P.; Gauthier, M.; D'Humieres, E.; Albertazzi, B.; Beaucourt, C.; Böker, J.; Chen, S.; Dervieux, V.; Feugeas, J. L.; Glesser, M.; Levy, A.; Nicolai, P.; Romagnani, L.; Tikhonchuk, V.; Pepin, H.; Fuchs, J.

    2012-10-01

    Intense research is being conducted on sources of laser-accelerated ions and their applications that have the potential of becoming novel particle sources. In most experiments, a high intensity and short laser pulse interacts with a solid density target. It was recently shown that a promising way to accelerate ions to higher energies and in a collimated beam is to use under-dense or near-critical density targets instead of solid ones. In these conditions, simulations have revealed that protons are predicted to be accelerated by a collisionless shock mechanism that significantly increases their energy. We present recent experiments performed on the 100 TW LULI laser (France) and the TITAN facility at LLNL, USA. The near critical density plasma was prepared by exploding thin solid foils by a long laser pulse. The plasma density profile was controlled by varying the target thickness and the delay between the long and the short laser pulse. When exploding the target, we obtained proton energies that are comparable if not higher than what was obtained under similar laser conditions, but with solid targets which make them a promising candidate for an efficient proton source.

  11. A coarse-grain force field for RDX: Density dependent and energy conserving.

    PubMed

    Moore, Joshua D; Barnes, Brian C; Izvekov, Sergei; Lísal, Martin; Sellers, Michael S; Taylor, DeCarlos E; Brennan, John K

    2016-03-14

    We describe the development of a density-dependent transferable coarse-grain model of crystalline hexahydro-1,3,5-trinitro-s-triazine (RDX) that can be used with the energy conserving dissipative particle dynamics method. The model is an extension of a recently reported one-site model of RDX that was developed by using a force-matching method. The density-dependent forces in that original model are provided through an interpolation scheme that poorly conserves energy. The development of the new model presented in this work first involved a multi-objective procedure to improve the structural and thermodynamic properties of the previous model, followed by the inclusion of the density dependency via a conservative form of the force field that conserves energy. The new model accurately predicts the density, structure, pressure-volume isotherm, bulk modulus, and elastic constants of the RDX crystal at ambient pressure and exhibits transferability to a liquid phase at melt conditions. PMID:26979691

  12. Strongly Interacting Matter Matter at Very High Energy Density: 3 Lectures in Zakopane

    SciTech Connect

    McLerran, L.

    2010-06-09

    These lectures concern the properties of strongly interacting matter at very high energy density. I begin with the Color Glass Condensate and the Glasma, matter that controls the earliest times in hadronic collisions. I then describe the Quark Gluon Plasma, matter produced from the thermalized remnants of the Glasma. Finally, I describe high density baryonic matter, in particular Quarkyonic matter. The discussion will be intuitive and based on simple structural aspects of QCD. There will be some discussion of experimental tests of these ideas.

  13. Measurements of continuous mix evolution in a high energy density shear flow

    SciTech Connect

    Loomis, E. Doss, F.; Flippo, K.; Fincke, J.

    2014-04-15

    We report on the novel integration of streaked radiography into a counter-flowing High Energy Density (HED) shear environment that continually measures a growing mix layer of Al separating two low-density CH foams. Measurements of the mix width allow us to validate compressible turbulence models and with streaked imaging, make this possible with a minimal number of experiments on large laser facilities. In this paper, we describe how the HED counter-flowing shear layer is created and diagnosed with streaked radiography. We then compare the streaked data to previous two-dimensional, single frame radiography and radiation hydrodynamic simulations of the experiment with inline compressible turbulent mix models.

  14. Level Density of COBALT-57 in the Energy Region 1 Mev to 14 Mev

    NASA Astrophysics Data System (ADS)

    Mishra, Vivek

    The level density of ^{57 }Co is studied in the energy region of 1-14 MeV using three experimental techniques. Levels are counted in the resolved region, evaporation spectra are measured in the resolved to continuum region, and the coherence width is measured in the region of level overlap. Use of Hauser-Feshbach fits to the evaporation cross sections requires level densities of the residual nucleus. A two -parameter based Fermi gas form is used for the calculation of level density as a function of the nuclear excitation energy. This procedure enables level density calculation beyond the energy region in which the two fixed parameters provide the best fits to the data. A comparison is made between the level density obtained from the above described methods and the predictions of the microscopic model in an energy range of 1-20 MeV. This model utilizes a BCS pairing Hamiltonian and specific sets of single particle states and calculates numerical values of the level density. Comparisons are also made with level density of ^{57 }Co obtained in various other studies. Both the resolved level studies and the fits to the evaporation spectra were conducted using the ^{56}Fe(d,n)^{57 }Co and ^{57}Fe(p,n) ^{57}Co reactions. Standard neutron time-of-flight techniques including pulse shape discrimination for elimination of gamma -rays were employed. An energy resolution as good as 6 keV at 1-1.5 MeV neutron energy was obtained for high resolution measurements. For Ericson fluctuation measurements, the excitation functions corresponding to the ground state and the first two excited states of the residual nucleus in the ^{56}Fe(p,n) ^{56}Co reaction were obtained for lab angles between 0^circ and 150^circ. The ^{56}Fe(d,n) ^{57}Co reaction proves to be very selective in populating resolved states and includes substantial contributions from mechanisms other than the compound nuclear. The ^{57 }Fe(p,n)^{57}Co reaction populated 14 previously unknown levels. The fits to the

  15. Fermi energy control of vacancy coalescence and dislocation density in melt-grown GaAs

    NASA Technical Reports Server (NTRS)

    Lagowski, J.; Gatos, H. C.; Lin, D. G.; Aoyama, T.

    1984-01-01

    A striking effect of the Fermi energy on the dislocation density in melt-grown GaAs has been discovered. Thus, a shift of the Fermi energy from 0.1 eV above to 0.2 eV below its intrinsic value (at high temperature, i.e., near 1100 K) increases the dislocation density by as much as five orders of magnitude. The Fermi energy shift was brought about by n-type and p-type doping at a level of about 10 to the 17th per cu cm (under conditions of optimum partial pressure of As, i.e., under optimum melt stoichiometry). This effect must be associated with the fact that the Fermi energy controls the charge state of vacancies (i.e., the occupancy of the associated electronic states) which in turn must control their tendency to coalesce and thus the dislocation density. It appears most likely that gallium vacancies are the critical species.

  16. Enhanced von Weizsäcker Wang-Govind-Carter kinetic energy density functional for semiconductors

    SciTech Connect

    Shin, Ilgyou; Carter, Emily A.

    2014-05-14

    We propose a new form of orbital-free (OF) kinetic energy density functional (KEDF) for semiconductors that is based on the Wang-Govind-Carter (WGC99) nonlocal KEDF. We enhance within the latter the semi-local von Weizsäcker KEDF term, which is exact for a single orbital. The enhancement factor we introduce is related to the extent to which the electron density is localized. The accuracy of the new KEDF is benchmarked against Kohn-Sham density functional theory (KSDFT) by comparing predicted energy differences between phases, equilibrium volumes, and bulk moduli for various semiconductors, along with metal-insulator phase transition pressures. We also compare point defect and (100) surface energies in silicon for a broad test of its applicability. This new KEDF accurately reproduces the exact non-interacting kinetic energy of KSDFT with only one additional adjustable parameter beyond the three parameters in the WGC99 KEDF; it exhibits good transferability between semiconducting to metallic silicon phases and between various III-V semiconductors without parameter adjustment. Overall, this KEDF is more accurate than previously proposed OF KEDFs (e.g., the Huang-Carter (HC) KEDF) for semiconductors, while the computational efficiency remains at the level of the WGC99 KEDF (several hundred times faster than the HC KEDF). This accurate, fast, and transferable new KEDF holds considerable promise for large-scale OFDFT simulations of metallic through semiconducting materials.

  17. High energy density rechargeable magnesium battery using earth-abundant and non-toxic elements

    NASA Astrophysics Data System (ADS)

    Orikasa, Yuki; Masese, Titus; Koyama, Yukinori; Mori, Takuya; Hattori, Masashi; Yamamoto, Kentaro; Okado, Tetsuya; Huang, Zhen-Dong; Minato, Taketoshi; Tassel, Cédric; Kim, Jungeun; Kobayashi, Yoji; Abe, Takeshi; Kageyama, Hiroshi; Uchimoto, Yoshiharu

    2014-07-01

    Rechargeable magnesium batteries are poised to be viable candidates for large-scale energy storage devices in smart grid communities and electric vehicles. However, the energy density of previously proposed rechargeable magnesium batteries is low, limited mainly by the cathode materials. Here, we present new design approaches for the cathode in order to realize a high-energy-density rechargeable magnesium battery system. Ion-exchanged MgFeSiO4 demonstrates a high reversible capacity exceeding 300 mAh.g-1 at a voltage of approximately 2.4 V vs. Mg. Further, the electronic and crystal structure of ion-exchanged MgFeSiO4 changes during the charging and discharging processes, which demonstrates the (de)insertion of magnesium in the host structure. The combination of ion-exchanged MgFeSiO4 with a magnesium bis(trifluoromethylsulfonyl)imide-triglyme electrolyte system proposed in this work provides a low-cost and practical rechargeable magnesium battery with high energy density, free from corrosion and safety problems.

  18. Symmetry energy at subsaturation densities and the neutron skin thickness of 208Pb

    NASA Astrophysics Data System (ADS)

    Fan, XiaoHua; Dong, JianMin; Zuo, Wei

    2015-06-01

    The mass-dependent symmetry energy coefficients a sym(A) has been extracted by analysing the heavy nuclear mass differences reducing the uncertainties as far as possible in our previous work. Taking advantage of the obtained symmetry energy coefficient a sym(A) and the density profiles obtained by switching off the Coulomb interaction in 208Pb, we calculated the slope parameter L 0.11 of the symmetry energy at the density of 0.11 fm-3. The calculated L 0.11 ranges from 40.5 MeV to 60.3 MeV. The slope parameter L 0.11 of the symmetry energy at the density of 0.11 fm-3 is also calculated directly with Skyrme interactions for nuclear matter and is found to have a fine linear relation with the neutron skin thickness of 208Pb, which is the difference of the neutron and proton rms radii of the nucleus. With the linear relation the neutron skin thickness Δ R np of 208Pb is predicted to be 0.15-0.21 fm.

  19. Structured block copolymer thin film composites for ultra-high energy density capacitors

    NASA Astrophysics Data System (ADS)

    Samant, Saumil; Hailu, Shimelis; Grabowski, Christopher; Durstock, Michael; Raghavan, Dharmaraj; Karim, Alamgir

    2014-03-01

    Development of high energy density capacitors is essential for future applications like hybrid vehicles and directed energy weaponry. Fundamentally, energy density is governed by product of dielectric permittivity ɛ and breakdown strength Vbd. Hence, improvements in energy density are greatly reliant on improving either ɛ or Vbd or a combination of both. Polymer films are widely used in capacitors due to high Vbd and low loss but they suffer from very low permittivities. Composite dielectrics offer a unique opportunity to combine the high ɛ of inorganic fillers with the high Vbd of a polymer matrix. For enhancement of dielectric properties, it is essential to improve matrix-filler interaction and control the spatial distribution of fillers for which nanostructured block copolymers BCP act as ideal templates. We use Directed Self-assembly of block copolymers to rapidly fabricate highly aligned BCP-TiO2 composite nanostructures in thin films under dynamic thermal gradient field to synergistically combine the high ɛ of functionalized TiO2 and high Vbd of BCP matrix. The results of impact of BCP morphology, processing conditions and concentration of TiO2 on capacitor performance will be reported. U.S. Air Force of Scientific Research under contract FA9550-12-1-0306

  20. High energy density rechargeable magnesium battery using earth-abundant and non-toxic elements

    PubMed Central

    Orikasa, Yuki; Masese, Titus; Koyama, Yukinori; Mori, Takuya; Hattori, Masashi; Yamamoto, Kentaro; Okado, Tetsuya; Huang, Zhen-Dong; Minato, Taketoshi; Tassel, Cédric; Kim, Jungeun; Kobayashi, Yoji; Abe, Takeshi; Kageyama, Hiroshi; Uchimoto, Yoshiharu

    2014-01-01

    Rechargeable magnesium batteries are poised to be viable candidates for large-scale energy storage devices in smart grid communities and electric vehicles. However, the energy density of previously proposed rechargeable magnesium batteries is low, limited mainly by the cathode materials. Here, we present new design approaches for the cathode in order to realize a high-energy-density rechargeable magnesium battery system. Ion-exchanged MgFeSiO4 demonstrates a high reversible capacity exceeding 300 mAh·g−1 at a voltage of approximately 2.4 V vs. Mg. Further, the electronic and crystal structure of ion-exchanged MgFeSiO4 changes during the charging and discharging processes, which demonstrates the (de)insertion of magnesium in the host structure. The combination of ion-exchanged MgFeSiO4 with a magnesium bis(trifluoromethylsulfonyl)imide–triglyme electrolyte system proposed in this work provides a low-cost and practical rechargeable magnesium battery with high energy density, free from corrosion and safety problems. PMID:25011939

  1. Enhanced von Weizsäcker Wang-Govind-Carter kinetic energy density functional for semiconductors

    NASA Astrophysics Data System (ADS)

    Shin, Ilgyou; Carter, Emily A.

    2014-05-01

    We propose a new form of orbital-free (OF) kinetic energy density functional (KEDF) for semiconductors that is based on the Wang-Govind-Carter (WGC99) nonlocal KEDF. We enhance within the latter the semi-local von Weizsäcker KEDF term, which is exact for a single orbital. The enhancement factor we introduce is related to the extent to which the electron density is localized. The accuracy of the new KEDF is benchmarked against Kohn-Sham density functional theory (KSDFT) by comparing predicted energy differences between phases, equilibrium volumes, and bulk moduli for various semiconductors, along with metal-insulator phase transition pressures. We also compare point defect and (100) surface energies in silicon for a broad test of its applicability. This new KEDF accurately reproduces the exact non-interacting kinetic energy of KSDFT with only one additional adjustable parameter beyond the three parameters in the WGC99 KEDF; it exhibits good transferability between semiconducting to metallic silicon phases and between various III-V semiconductors without parameter adjustment. Overall, this KEDF is more accurate than previously proposed OF KEDFs (e.g., the Huang-Carter (HC) KEDF) for semiconductors, while the computational efficiency remains at the level of the WGC99 KEDF (several hundred times faster than the HC KEDF). This accurate, fast, and transferable new KEDF holds considerable promise for large-scale OFDFT simulations of metallic through semiconducting materials.

  2. High energy density rechargeable magnesium battery using earth-abundant and non-toxic elements.

    PubMed

    Orikasa, Yuki; Masese, Titus; Koyama, Yukinori; Mori, Takuya; Hattori, Masashi; Yamamoto, Kentaro; Okado, Tetsuya; Huang, Zhen-Dong; Minato, Taketoshi; Tassel, Cédric; Kim, Jungeun; Kobayashi, Yoji; Abe, Takeshi; Kageyama, Hiroshi; Uchimoto, Yoshiharu

    2014-01-01

    Rechargeable magnesium batteries are poised to be viable candidates for large-scale energy storage devices in smart grid communities and electric vehicles. However, the energy density of previously proposed rechargeable magnesium batteries is low, limited mainly by the cathode materials. Here, we present new design approaches for the cathode in order to realize a high-energy-density rechargeable magnesium battery system. Ion-exchanged MgFeSiO4 demonstrates a high reversible capacity exceeding 300 Ah · g(-1) at a voltage of approximately 2.4 V vs. Mg. Further, the electronic and crystal structure of ion-exchanged MgFeSiO4 changes during the charging and discharging processes, which demonstrates the (de)insertion of magnesium in the host structure. The combination of ion-exchanged MgFeSiO4 with a magnesium bis(trifluoromethylsulfonyl)imide-triglyme electrolyte system proposed in this work provides a low-cost and practical rechargeable magnesium battery with high energy density, free from corrosion and safety problems. PMID:25011939

  3. Pie-like electrode design for high-energy density lithium–sulfur batteries

    PubMed Central

    Li, Zhen; Zhang, Jin Tao; Chen, Yu Ming; Li, Ju; Lou, Xiong Wen (David)

    2015-01-01

    Owing to the overwhelming advantage in energy density, lithium–sulfur (Li–S) battery is a promising next-generation electrochemical energy storage system. Despite many efforts in pursuing long cycle life, relatively little emphasis has been placed on increasing the areal energy density. Herein, we have designed and developed a ‘pie' structured electrode, which provides an excellent balance between gravimetric and areal energy densities. Combining lotus root-like multichannel carbon nanofibers ‘filling' and amino-functionalized graphene ‘crust', the free-standing paper electrode (S mass loading: 3.6 mg cm−2) delivers high specific capacity of 1,314 mAh g−1 (4.7 mAh cm−2) at 0.1 C (0.6 mA cm−2) accompanied with good cycling stability. Moreover, the areal capacity can be further boosted to more than 8 mAh cm−2 by stacking three layers of paper electrodes with S mass loading of 10.8 mg cm−2. PMID:26608228

  4. Pie-like electrode design for high-energy density lithium-sulfur batteries

    NASA Astrophysics Data System (ADS)

    Li, Zhen; Zhang, Jin Tao; Chen, Yu Ming; Li, Ju; Lou, Xiong Wen (David)

    2015-11-01

    Owing to the overwhelming advantage in energy density, lithium-sulfur (Li-S) battery is a promising next-generation electrochemical energy storage system. Despite many efforts in pursuing long cycle life, relatively little emphasis has been placed on increasing the areal energy density. Herein, we have designed and developed a `pie' structured electrode, which provides an excellent balance between gravimetric and areal energy densities. Combining lotus root-like multichannel carbon nanofibers `filling' and amino-functionalized graphene `crust', the free-standing paper electrode (S mass loading: 3.6 mg cm-2) delivers high specific capacity of 1,314 mAh g-1 (4.7 mAh cm-2) at 0.1 C (0.6 mA cm-2) accompanied with good cycling stability. Moreover, the areal capacity can be further boosted to more than 8 mAh cm-2 by stacking three layers of paper electrodes with S mass loading of 10.8 mg cm-2.

  5. Impact of the Pedestal Plasma Density on ELM Dynamics and Energy Loss Scaling

    NASA Astrophysics Data System (ADS)

    Xu, X. Q.; Ma, J. F.; Li, G. Q.; BOUT++ Collaboration

    2014-10-01

    The latest BOUT + + studies show an emerging understanding of ELM dynamics and the consistent collisionality scaling of ELM energy losses with ITPA multi-tokamak database. A series of BOUT + + simulations are conducted to investigate the scaling characteristics of the ELM energy losses vs collisionality via a density scan, while keeping the plasma cross-sectional shape, total stored energy, total plasma current, pressure profiles fixed. The neoclassical collisionality at peak gradient position increases by a factor of 3262 from 0.0019 to 6.197. The critical trend of linear simulations emerges as a transition from ballooning-dominated states at high collisionality to peeling-dominated states at low collsionality with decreasing density. Nonlinear BOUT + + simulations show a two-stage process of ELM crash evolution of (i) initial bursts of pressure blob and void creation and (ii) inward turbulence spreading as void propagation. The inward void propagation stirs the top of pedestal plasma and yields an increasing ELM size with decreasing collisionality after a series of micro-bursts. The pedestal plasma density plays a major role in determining the ELM energy loss through its effect on the edge bootstrap current and ion diamagnetic stabilization. This work was performed for USDOE by LLNL under DE-AC52-07NA27344, LLNL LDRD project 12-ERD-022 and the China Natural Science Foundation under Contract No. 10721505. LLNL-ABS-656793.

  6. SU-D-204-01: Dual-Energy Calibration for Breast Density Measurement Using Spectral Mammography

    SciTech Connect

    Ding, H; Cho, H; Kumar, N; Sennung, D; Molloi, S

    2015-06-15

    Purpose: To investigate the feasibility of minimizing the systematic errors in dual-energy breast density quantification induced by the use of tissue-equivalent plastic phantoms as the calibration basis materials. Methods: Dual-energy calibration using tissue-equivalent plastic phantoms was performed on a spectral mammography system based on scanning multi-slit Si strip photon-counting detectors. The plastic phantom calibration used plastic water and adipose-equivalent phantoms as the basis materials, which have different x-ray attenuation properties compared to water and lipid in actual breast tissue. Two methods were used to convert the dual-energy decomposition measurements in plastic phantom thicknesses into true water and lipid basis. The first method was based entirely on the theoretical x-ray attenuation coefficients of the investigated materials in the mammographic energy range. The conversion matrix was determined from least-squares fitting of the target material using the reported attenuation coefficients of water and lipid. The second method was developed based on experimental calibrations, which measured the low-and high-energy signals of pure water and lipid of known thicknesses. A non-linear rational function was used to correlate the decomposed thicknesses to the known values, so that the conversion coefficients can be determined. Both methods were validated using independent measurements of water and lipid mixture phantoms. The correlation of the dual-energy decomposition measurements and the known values were studied with linear regression analysis. Results: There was an excellent linear correlation between the converted water thicknesses and the known values. The slopes of the linear fits were determined to be 0.63 and 1.03 for the simulation and experimental results, respectively. The non-linear fitting in the experimental approach reduced the root-mean-square (RMS) errors from approximately 3.4 mm to 1.5 mm. Conclusion: The results suggested

  7. Self-suspended vibration-driven energy harvesting chip for power density maximization

    NASA Astrophysics Data System (ADS)

    Murillo, Gonzalo; Agustí, Jordi; Abadal, Gabriel

    2015-11-01

    This work introduces a new concept to integrate energy-harvesting devices with the aim of improving their throughput, mainly in terms of scavenged energy density and frequency tunability. This concept, named energy harvester in package (EHiP), is focused on the heterogeneous integration of a MEMS die, dedicated to scavenging energy, with an auxiliary chip, which can include the control and power management circuitry, sensors and RF transmission capabilities. The main advantages are that the whole die can be used as an inertial mass and the chip area usage is optimized. Based on this concept, in this paper we describe the development and characterization of a MEMS die fully dedicated to harvesting mechanical energy from ambient vibrations through an electrostatic transduction. A test PCB has been fabricated to perform the assembly that allows measurement of the resonance motion of the whole system at 289 Hz. An estimated maximum generated power of around 11 μW has been obtained for an input vibration acceleration of ˜10 m s-2 when the energy harvester operates in a constant-charge cycle for the best-case scenario. Therefore, a maximum scavenged power density of 0.85 mW cm-3 is theoretically expected for the assembled system. These results demonstrate that the generated power density of any vibration-based energy harvester can be significantly increased by applying the EHiP concept, which could become an industrial standard for manufacturing this kind of system, independently of the transduction type, fabrication technology or application.

  8. Short-term overeating results in incomplete energy intake compensation regardless of energy density or macronutrient composition

    PubMed Central

    Apolzan, John W.; Bray, George A.; Hamilton, Marc T.; Zderic, Theodore W.; Han, Hongmei; Champagne, Catherine M.; Shepard, Desti; Martin, Corby K.

    2013-01-01

    Objective To evaluate the effects of overeating (140% of energy requirements) a high-fat low-energy density diet (HF/LED, 1.05kcal/g), high-fat high-energy density diet (HF/HED, 1.60kcal/g), and high-carbohydrate (HC) LED (1.05kcal/g) for 2-days on subsequent 4-day energy intake (EI), activity levels, appetite, and mood. Design and Methods Using a randomized cross-over design, energy expenditure and EI were standardized during overeating. Results In 20 adults with a mean±SD BMI of 30.7±4.6kg/m2, EI was not suppressed until the second day after overeating and accounted for ~30% of the excess EI. Reductions in EI did not differ among the 3 diets or across days. Overeating had no effect on subsequent energy expenditure but steps/day decreased after the HC/LED and HF/HED. Sleep time was increased after the HF/HED compared to both LEDs. After overeating a HF/HED vs. HF/LED, carbohydrate cravings, hunger, prospective food consumption, and sadness increased and satisfaction, relaxation, and tranquility decreased. Conclusions Diet type, time, or their interaction had no impact on compensation over 4 days. No adaptive thermogenesis was observed. The HF/HED vs. HF/LED had detrimental effects on food cravings, appetite, and mood. These results suggest short-term overeating is associated with incomplete compensation. PMID:23913807

  9. Kohn-Sham kinetic energy density in the nuclear and asymptotic regions: Deviations from the von Weizsäcker behavior and applications to density functionals

    NASA Astrophysics Data System (ADS)

    Della Sala, Fabio; Fabiano, Eduardo; Constantin, Lucian A.

    2015-01-01

    We show that the Kohn-Sham positive-definite kinetic energy (KE) density significantly differs from the von Weizsäcker (VW) one at the nuclear cusp as well as in the asymptotic region. At the nuclear cusp, the VW functional is shown to be linear, and the contribution of p -type orbitals to the KE density is theoretically derived and numerically demonstrated in the limit of infinite nuclear charge as well in the semiclassical limit of neutral large atoms. In the latter case, it reaches 12% of the KE density. In the asymptotic region we find new exact constraints for meta-generalized gradient approximation (meta-GGA) exchange functionals: with an exchange enhancement factor proportional to √{α }, where α is the common meta-GGA ingredient, both the exchange energy density and the potential are proportional to the exact ones. In addition, this describes exactly the large-gradient limit of quasi-two-dimensional systems.

  10. Screened exchange hybrid density functional for accurate and efficient structures and interaction energies.

    PubMed

    Brandenburg, Jan Gerit; Caldeweyher, Eike; Grimme, Stefan

    2016-06-21

    We extend the recently introduced PBEh-3c global hybrid density functional [S. Grimme et al., J. Chem. Phys., 2015, 143, 054107] by a screened Fock exchange variant based on the Henderson-Janesko-Scuseria exchange hole model. While the excellent performance of the global hybrid is maintained for small covalently bound molecules, its performance for computed condensed phase mass densities is further improved. Most importantly, a speed up of 30 to 50% can be achieved and especially for small orbital energy gap cases, the method is numerically much more robust. The latter point is important for many applications, e.g., for metal-organic frameworks, organic semiconductors, or protein structures. This enables an accurate density functional based electronic structure calculation of a full DNA helix structure on a single core desktop computer which is presented as an example in addition to comprehensive benchmark results. PMID:27240749

  11. Equation of state for compressed liquids and their mixtures from the cohesive energy density

    NASA Astrophysics Data System (ADS)

    Boushehri, A.; Mason, E. A.

    1993-07-01

    A procedure is presented, based on statistical-mechanical theory, for predicting the equation of state of compressed normal liquids and their mixtures from two scaling constants that are available from measurements at ordinary pressures and temperatures. The theoretical equation of state is that of Ihm, Song, and Mason, and the two constants are the enthalpy of vaporization and the liquid density at the triple point, which are related to the cohesive energy density of regular solution theory. The procedure is tested on a number of substances ranging in complexity from Ar and CO2 to n-heptane and toluene. The results indicate that the liquid density at any pressure and temperature can be predicted within about 5%, over the range from T tp to T c and up to the freezing line. Possible methods of determining the scaling constants are discussed, as well as other possible choices for scaling constants.

  12. Elastic proton scattering at intermediate energies as a probe of the He,86 nuclear matter densities

    NASA Astrophysics Data System (ADS)

    Chung, Le Xuan; Kiselev, Oleg A.; Khoa, Dao T.; Egelhof, Peter

    2015-09-01

    The Glauber model analysis of the elastic He,86+p scattering data at energies around 700 MeV/nucleon, measured in two separate experiments at GSI-Darmstadt, has been carried out using several phenomenological parametrizations of the nuclear matter density. By taking into account the new data points measured at high-momentum transfer, the nuclear matter radii of ,8He6 have been accurately determined from the Glauber model analysis of the data, with the spin-orbital interaction explicitly taken into account. The well-known geometry for the core and dineutron halo has been used with the new parametrizations of the 6He density to extract the detailed information on the structure of 6He in terms of the core and dineutron halo radii. An enhanced sensitivity of the data measured at high-momentum transfer to the core part of the 6,8He densities has been found.

  13. Solar Thermal Energy Storage Device: Hybrid Nanostructures for High-Energy-Density Solar Thermal Fuels

    SciTech Connect

    2012-01-09

    HEATS Project: MIT is developing a thermal energy storage device that captures energy from the sun; this energy can be stored and released at a later time when it is needed most. Within the device, the absorption of sunlight causes the solar thermal fuel’s photoactive molecules to change shape, which allows energy to be stored within their chemical bonds. A trigger is applied to release the stored energy as heat, where it can be converted into electricity or used directly as heat. The molecules would then revert to their original shape, and can be recharged using sunlight to begin the process anew. MIT’s technology would be 100% renewable, rechargeable like a battery, and emissions-free. Devices using these solar thermal fuels—called Hybrisol—can also be used without a grid infrastructure for applications such as de-icing, heating, cooking, and water purification.

  14. Electron density profile measurements at a self-focusing ion beam with high current density and low energy extracted through concave electrodes

    SciTech Connect

    Fujiwara, Y. Nakamiya, A.; Sakakita, H.; Hirano, Y.; Kiyama, S.; Koguchi, H.

    2014-02-15

    The self-focusing phenomenon has been observed in a high current density and low energy ion beam. In order to study the mechanism of this phenomenon, a special designed double probe to measure the electron density and temperature is installed into the chamber where the high current density ion beam is injected. Electron density profile is successfully measured without the influence of the ion beam components. Estimated electron temperature and density are ∼0.9 eV and ∼8 × 10{sup 8} cm{sup −3} at the center of ion beam cross section, respectively. It was found that a large amount of electrons are spontaneously accumulated in the ion beam line in the case of self-forcing state.

  15. Nonuniqueness of magnetic fields and energy derivatives in spin-polarized density functional theory

    NASA Astrophysics Data System (ADS)

    Gál, T.; Ayers, P. W.; De Proft, F.; Geerlings, P.

    2009-10-01

    The effect of the recently uncovered nonuniqueness of the external magnetic field B(r⃑) corresponding to a given pair of density n(r⃑) and spin density ns(r⃑) on the derivative of the energy functional of spin-polarized density functional theory, and its implications for the definition of chemical reactivity descriptors, is examined. For ground states, the nonuniqueness of B(r⃑) implies the nondifferentiability of the energy functional Ev,B[n,ns] with respect to ns(r⃑). It is shown, on the other hand, that this nonuniqueness allows the existence of the one-sided derivatives of Ev,B[n,ns] with respect to ns(r⃑). Although the N-electron ground state can always be obtained from the minimization of Ev,B[n,ns] without any constraint on the spin number Ns=∫ns(r⃑)dr⃑, the Lagrange multiplier μs associated with the fixation of Ns does not vanish even for ground states. μs is identified as the left- or right-side derivative of the total energy with respect to Ns, which justifies the interpretation of μs as a (spin) chemical potential. This is relevant not only for the spin-polarized generalization of conceptual density functional theory, the spin chemical potential being one of the elementary reactivity descriptors, but also for the extension of the thermodynamical analogy of density functional theory for the spin-polarized case. For higher-order reactivity indices, B(r⃑)'s nonuniqueness has similar implications as for μs, leading to a split of the indices with respect to Ns into one-sided reactivity descriptors.

  16. Effects of palatability and learned satiety on energy density influences on breakfast intake in humans.

    PubMed

    Yeomans, Martin R; Weinberg, Laura; James, Sarah

    2005-11-15

    The present report explored firstly how palatability modified the effects of energy density (ED) on short-term food intake and changes in rated appetite within a single test meal, and secondly how repeated consumption altered these relationships. Experiment 1 contrasted disguised high (HED) and low (LED) versions of a food presented in bland and palatable forms. Mass consumed varied as an interaction of palatability and ED, with subjects eating least of the bland/HED version, suggesting some un-learned satiating effects. No such compensation for ED was seen in the palatable/HED condition, and overall energy intake increased with ED. Palatability had the expected stimulatory effect on appetite, but rated hunger decreased more rapidly as a function of energy consumed in the HED conditions. Experiment 2 introduced novel distinctive flavours to examine whether repeated experience of palatable HED and LED versions resulted in learned satiety. Participants ate the same mass of LED and HED versions on first exposure, but after two training days with each food, where they consumed a fixed amount, they subsequently ate a greater mass of the LED version, consistent with learned satiety. Increased intake was accompanied by a slower rate of decline in hunger in the LED condition. Despite these changes, energy intake remained higher with the HED version. Liking for the LED version was greater than the HED version at the end, possibly due to mild aversive qualities of eating a fixed portion of the HED food during training. Together these data suggest that energy density is the major determinant of short-term energy intake in the absence of orosensory cues predictive of energy differences, but that learning of flavour-energy associations can, to some extent, allow short-term energy consumption to be regulated. PMID:16165170

  17. Improved parameterization of interatomic potentials for rare gas dimers with density-based energy decomposition analysis

    NASA Astrophysics Data System (ADS)

    Zhou, Nengjie; Lu, Zhenyu; Wu, Qin; Zhang, Yingkai

    2014-06-01

    We examine interatomic interactions for rare gas dimers using the density-based energy decomposition analysis (DEDA) in conjunction with computational results from CCSD(T) at the complete basis set (CBS) limit. The unique DEDA capability of separating frozen density interactions from density relaxation contributions is employed to yield clean interaction components, and the results are found to be consistent with the typical physical picture that density relaxations play a very minimal role in rare gas interactions. Equipped with each interaction component as reference, we develop a new three-term molecular mechanical force field to describe rare gas dimers: a smeared charge multipole model for electrostatics with charge penetration effects, a B3LYP-D3 dispersion term for asymptotically correct long-range attractions that is screened at short-range, and a Born-Mayer exponential function for the repulsion. The resulted force field not only reproduces rare gas interaction energies calculated at the CCSD(T)/CBS level, but also yields each interaction component (electrostatic or van der Waals) which agrees very well with its corresponding reference value.

  18. Improved parameterization of interatomic potentials for rare gas dimers with density-based energy decomposition analysis.

    PubMed

    Zhou, Nengjie; Lu, Zhenyu; Wu, Qin; Zhang, Yingkai

    2014-06-01

    We examine interatomic interactions for rare gas dimers using the density-based energy decomposition analysis (DEDA) in conjunction with computational results from CCSD(T) at the complete basis set (CBS) limit. The unique DEDA capability of separating frozen density interactions from density relaxation contributions is employed to yield clean interaction components, and the results are found to be consistent with the typical physical picture that density relaxations play a very minimal role in rare gas interactions. Equipped with each interaction component as reference, we develop a new three-term molecular mechanical force field to describe rare gas dimers: a smeared charge multipole model for electrostatics with charge penetration effects, a B3LYP-D3 dispersion term for asymptotically correct long-range attractions that is screened at short-range, and a Born-Mayer exponential function for the repulsion. The resulted force field not only reproduces rare gas interaction energies calculated at the CCSD(T)/CBS level, but also yields each interaction component (electrostatic or van der Waals) which agrees very well with its corresponding reference value. PMID:24908000

  19. Improved parameterization of interatomic potentials for rare gas dimers with density-based energy decomposition analysis

    PubMed Central

    Zhou, Nengjie; Lu, Zhenyu; Wu, Qin; Zhang, Yingkai

    2014-01-01

    We examine interatomic interactions for rare gas dimers using the density-based energy decomposition analysis (DEDA) in conjunction with computational results from CCSD(T) at the complete basis set (CBS) limit. The unique DEDA capability of separating frozen density interactions from density relaxation contributions is employed to yield clean interaction components, and the results are found to be consistent with the typical physical picture that density relaxations play a very minimal role in rare gas interactions. Equipped with each interaction component as reference, we develop a new three-term molecular mechanical force field to describe rare gas dimers: a smeared charge multipole model for electrostatics with charge penetration effects, a B3LYP-D3 dispersion term for asymptotically correct long-range attractions that is screened at short-range, and a Born-Mayer exponential function for the repulsion. The resulted force field not only reproduces rare gas interaction energies calculated at the CCSD(T)/CBS level, but also yields each interaction component (electrostatic or van der Waals) which agrees very well with its corresponding reference value. PMID:24908000

  20. Neutron-proton effective mass splitting in terms of symmetry energy and its density slope

    SciTech Connect

    Chakraborty, S.; Sahoo, B.; Sahoo, S.

    2015-01-15

    Using a simple density-dependent finite-range effective interaction having Yukawa form, the density dependence of isoscalar and isovector effective masses is studied. The isovector effective mass is found to be different for different pairs of like and unlike nucleons. Using HVH theorem, the neutron-proton effective mass splitting is represented in terms of symmetry energy and its density slope. It is again observed that the neutron-proton effective mass splitting has got a positive value when isoscalar effective mass is greater than the isovector effective mass and has a negative value for the opposite case. Furthermore, the neutron-proton effective mass splitting is found to have a linear dependence on asymmetry β. The second-order symmetry potential has a vital role in the determination of density slope of symmetry energy but it does not have any contribution on neutron-proton effective mass splitting. The finite-range effective interaction is compared with the SLy2, SKM, f{sub −}, f{sub 0}, and f{sub +} forms of interactions.

  1. Design and simulation of high-energy-density shear experiments on OMEGA and the NIF

    NASA Astrophysics Data System (ADS)

    Doss, F. W.; Devolder, B.; di Stefano, C.; Flippo, K. A.; Kline, J. L.; Kot, L.; Loomis, E. N.; Merritt, E. C.; Perry, T. S.; MacLaren, S. A.; Wang, P.; Zhou, Y. K.

    2015-11-01

    High-energy-density shear experiments have been performed by LANL at the OMEGA Laser Facility and National Ignition Facility (NIF). The experiments have been simulated using the LANL radiation-hydrocode RAGE and have been used to assess turbulence models' ability to function in the high-energy-density, inertial-fusion-relevant regime. Beginning with the basic configuration of two counter-oriented shock-driven flows of > 100 km/s, which initiate a strong shear instability across an initially solid density, 20 micron thick Al plate, variations of the experiment have been performed and are studied. These variations have included increasing the fluid density (by modifying the metal plate material from Al to Ti), imposing sinusoidal perturbations on the plate, and directly modifying the plate's intrinsic surface roughness. In addition to examining the shear-induced mixing, the simulations reveal other physics, such as how the interaction of our indirect-drive halfraums with a mated shock tube's ablator impedes a stagnation-driven shock. This work is conducted by the US DOE by LANL under contract DE-AC52-06NA25396, and NIF facility operations by LLNL under contract DE-AC52-07NA27344.

  2. Activated Microporous Carbon Derived from Almond Shells for High Energy Density Asymmetric Supercapacitors.

    PubMed

    Wu, Chun; Yang, Shaoran; Cai, Junjie; Zhang, Qiaobao; Zhu, Ying; Zhang, Kaili

    2016-06-22

    Via the activation treatment of carbonized almond shells with HNO3 and KOH, activated microporous carbon (AMC-3 and AMC-2) was successfully synthesized. These two AMC electrodes demonstrate remarkable electrochemical behaviors such as high rate capability, high specific capacitance, and excellent cycle stability when serving as electrodes for supercapacitors. More importantly, through the use of a Zn-Ni-Co ternary oxide (ZNCO) positive electrode and the AMC negative electrode, asymmetric supercapacitors (ASC) were assembled that deliver superior energy density (53.3 Wh kg(-1) at a power density of 1126.1 W kg(-1) for ASC-2 and 53.6 Wh kg(-1) at a power density of 1124.5 W kg(-1) for ASC-3) and excellent stability (82.7% and 83.4% specific capacitance retention for ZNCO//AMC ASC-2 and ZNCO//AMC ASC-3, respectively, after 5000 cycles). Through these two methods, low-cost, renewable, and environmentally friendly electrode materials can be provided for high energy density supercapacitors. PMID:27253880

  3. Measurements of the Electron Cloud Density in the PEP-II Low Energy Ring

    SciTech Connect

    Byrd, J.; De Santis, S.; Sonnad, K.; Caspers, F.; Kroyer, T.; Krasnykh, A.; Pivi, M.; /SLAC

    2012-04-10

    Clouds of low energy electrons in the vacuum beam pipes of accelerators of positively charged particle beams present a serious limitation for operation of these machines at high currents. Because of the size of these accelerators, it is difficult to probe the low energy electron clouds over substantial lengths of the beam pipe. We have developed a novel technique to directly measure the electron cloud density via the phase shift induced in a TE wave that is independently excited and transmitted over a section of the accelerator. We infer the absolute phase shift with relatively high accuracy from the phase modulation of the transmission due to the modulation of the electron cloud density from a gap in the positively charged beam. We have used this technique for the first time to measure the average electron cloud density over a 50 m straight section in the positron ring of the PEP-II collider at the Stanford Linear Accelerator Center. We have also measured the variation of the density by using low field solenoid magnets to control the electrons.

  4. Strongly Driven Magnetic Reconnection in a Magnetized High-Energy-Density Plasma

    NASA Astrophysics Data System (ADS)

    Fiksel, G.; Barnak, D. H.; Chang, P.-Y.; Haberberger, D.; Hu, S. X.; Ivancic, S.; Nilson, P. M.; Fox, W.; Deng, W.; Bhattacharjee, A.; Germaschewski, K.

    2014-10-01

    Magnetic reconnection in a magnetized high-energy-density plasma is characterized by measuring the dynamics of the plasma density and magnetic field between two counter-propagating and colliding plasma flows. The density and magnetic field were profiled using the 4 ω angular filter refractometry and fast proton deflectometry diagnostics, respectively. The plasma flows are created by irradiating oppositely placed plastic targets with 1.8-kJ, 2-ns laser beams on the OMEGA EP Laser System. The two plumes are magnetized by an externally controlled magnetic field with an x-type null point geometry with B = 0 at the midplane and B = 8 T at the targets. The interaction region is pre-filled with a low-density background plasma. The counterflowing super-Alfvénic plasma plumes sweep up and compress the magnetic field and the background plasma into a pair of magnetized ribbons, which collide, stagnate, and reconnect at the midplane, allowing for the first detailed observation of a stretched current sheet in laser-driven reconnection experiments. The measurements are in good agreement with first-principles particle-in-cell simulations. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0001944 and NLUF Grant DE-SC0008655.

  5. Review of Rapidity Density Distributions in Heavy-Ion Induced Interactions at Relativistic Energies

    NASA Astrophysics Data System (ADS)

    Aggarwal, Madan M.; Garpman, Sten I. A.

    Violent interactions among colliding nuclei ultimately provide the suitable conditions for creating new and hitherto unexplored phenomena like color rope and quark-gluon plasma formation. The systemmatics achieved so far in pseudorapidity and density distributions of charged particles emitted from relativistic nucleus-nucleus collisions is reviewed and comparisons to model predictions are made. Data from both emulsion and counter experiments are utilized and the dependence of the angular spectra on projectile energy, centrality measured by means of forward charge or enegy flow, and on the projectile/target masses are reported. For a few central events, energy densities of the hot overlap zone are estimated to be beyond onset of deconfinement phase transition.

  6. Energy density dependence of hydrogen combustion efficiency in atmospheric pressure microwave plasma

    SciTech Connect

    Yoshida, T.; Ezumi, N.; Sawada, K.; Tanaka, Y.; Tanaka, M.; Nishimura, K.

    2015-03-15

    The recovery of tritium in nuclear fusion plants is a key issue for safety. So far, the oxidation procedure using an atmospheric pressure plasma is expected to be part of the recovery method. In this study, in order to clarify the mechanism of hydrogen oxidation by plasma chemistry, we have investigated the dependence of hydrogen combustion efficiency on gas flow rate and input power in the atmospheric pressure microwave plasma. It has been found that the combustion efficiency depends on energy density of absorbed microwave power. Hence, the energy density is considered as a key parameter for combustion processes. Also neutral gas temperatures inside and outside the plasma were measured by an optical emission spectroscopy method and thermocouple. The result shows that the neutral gas temperature in the plasma is much higher than the outside temperature of plasma. The high neutral gas temperature may affect the combustion reaction. (authors)

  7. Mixed metal oxides as alternate cathodes for high energy density electric propulsion

    SciTech Connect

    Papp, J.E.

    1995-12-31

    Silver (II) oxide is currently the Navy`s cathode of choice in high energy density, high rate batteries for torpedo and mobile target applications, for medium rate applications such as Seal Delivery Vehicles, and may be useful for low rate, long endurance UUV missions. While it is certainly a versatile material, silver (II) oxide is expensive to produce and has a lower faradaic (storage) capacity than desired. New research being conducted at the NUWC electric propulsion laboratory is focused toward developing new, lower cost cathode materials with energy densities at least comparable to silver (II) oxide. Mixed metal oxides, with silver (II) oxide as one component, are under investigation. Other materials, without a silver component, are also being considered. This poster will illustrate recent developments in the modification of the silver (II) oxide cathode for Navy applications.

  8. Measurements of ion stopping around the Bragg peak in high-energy-density plasmas

    SciTech Connect

    Frenje, J. A.; Grabowski, P. E.; Li, C. K.; Seguin, F. H.; Zylstra, A. B.; Gatu Johnson, M.; Petrasso, R. D.; Glebov, V. Yu; Sangster, T. C.

    2015-11-09

    For the first time, quantitative measurements of ion stopping at energies about the Bragg peak (or peak ion stopping, which occurs at an ion velocity comparable to the average thermal electron velocity), and its dependence on electron temperature (Te) and electron number density (ne) in the range of 0.5 – 4.0 keV and 3 × 1022 – 3 × 1023 cm-3 have been conducted, respectively. It is experimentally demonstrated that the position and amplitude of the Bragg peak varies strongly with Te with ne. As a result, the importance of including quantum diffraction is also demonstrated in the stopping-power modeling of High-Energy-Density Plasmas.

  9. Measurements of ion stopping around the Bragg peak in high-energy-density plasmas

    DOE PAGESBeta

    Frenje, J. A.; Grabowski, P. E.; Li, C. K.; Seguin, F. H.; Zylstra, A. B.; Gatu Johnson, M.; Petrasso, R. D.; Glebov, V. Yu; Sangster, T. C.

    2015-11-09

    For the first time, quantitative measurements of ion stopping at energies about the Bragg peak (or peak ion stopping, which occurs at an ion velocity comparable to the average thermal electron velocity), and its dependence on electron temperature (Te) and electron number density (ne) in the range of 0.5 – 4.0 keV and 3 × 1022 – 3 × 1023 cm-3 have been conducted, respectively. It is experimentally demonstrated that the position and amplitude of the Bragg peak varies strongly with Te with ne. As a result, the importance of including quantum diffraction is also demonstrated in the stopping-power modelingmore » of High-Energy-Density Plasmas.« less

  10. Measurements of Ion Stopping Around the Bragg Peak in High-Energy-Density Plasmas.

    PubMed

    Frenje, J A; Grabowski, P E; Li, C K; Séguin, F H; Zylstra, A B; Gatu Johnson, M; Petrasso, R D; Glebov, V Yu; Sangster, T C

    2015-11-13

    For the first time, quantitative measurements of ion stopping at energies around the Bragg peak (or peak ion stopping, which occurs at an ion velocity comparable to the average thermal electron velocity), and its dependence on electron temperature (T(e)) and electron number density (n(e)) in the range of 0.5-4.0 keV and 3×10(22) to 3×10(23) cm(-3) have been conducted, respectively. It is experimentally demonstrated that the position and amplitude of the Bragg peak varies strongly with T(e) with n(e). The importance of including quantum diffraction is also demonstrated in the stopping-power modeling of high-energy-density plasmas. PMID:26613448

  11. Effect of gamma irradiation on viscosity reduction of cereal porridges for improving energy density

    NASA Astrophysics Data System (ADS)

    Lee, Ju-Woon; Kim, Jae-Hun; Oh, Sang-Hee; Byun, Eui-Hong; Yook, Hong-Sun; Kim, Mee-Ree; Kim, Kwan-Soo; Byun, Myung-Woo

    2008-03-01

    Cereal porridges have low energy and nutrient density because of its viscosity. The objective of the present study was to evaluate the effect of irradiation on the reduction of viscosity and on the increasing solid content of cereal porridge. Four cereals, wheat, rice, maize (the normal starchy type) and waxy rice, were used in this study. The porridge with 3000 cP was individually prepared from cereal flour, gamma-irradiated at 20 kGy and tested. Gamma irradiation of 20 kGy was allowed that the high viscous and rigid cereal porridges turned into semi-liquid consistencies. The solid contents of all porridges could increase by irradiation, compared with non-irradiated ones. No significant differences of starch digestibility were observed in all cereal porridge samples. The results indicated that gamma irradiation might be helpful for improving energy density of cereal porridge with acceptable consistency.

  12. High-Energy Density science at the Linac Coherent Light Source

    NASA Astrophysics Data System (ADS)

    Glenzer, S. H.; Fletcher, L. B.; Hastings, J. B.

    2016-03-01

    The Matter in Extreme Conditions end station at the Linac Coherent Light Source holds great promise for novel pump-probe experiments to make new discoveries in high- energy density science. In recent experiments we have demonstrated the first spectrally- resolved measurements of plasmons using a seeded 8-keV x-ray laser beam. Forward x-ray Thomson scattering spectra from isochorically heated solid aluminum show a well-resolved plasmon feature that is down-shifted in energy by 19 eV from the incident 8 keV elastic scattering feature. In this spectral range, the simultaneously measured backscatter spectrum shows no spectral features indicating observation of collective plasmon oscillations on a scattering length comparable to the screening length. This technique is a prerequisite for Thomson scattering measurements in compressed matter where the plasmon shift is a sensitive function of the free electron density and where the plasmon intensity provides information on temperature.

  13. Effect of preparation method on viscosity and energy density of fortified humanitarian food-aid commodities.

    PubMed

    Black, Cameron T; Pahulu, Heather F; Dunn, Michael L

    2009-01-01

    Corn soy blend, wheat soy blend, and corn soy milk are fortified food-aid commodities distributed by the US Government, and often used in complementary feeding programs. The viscosity and energy density of these products was compared in cooked porridges, at concentrations between 8% and 20% (w/w), using a Bostwick consistometer. All three products required nearly 20% addition of dry meal in water to achieve the energy density of 0.8 kcal/g, recommended for complementary foods. At this concentration, all three were excessively viscous. Cooking times beyond 1 min showed no significant increase in viscosity. Corn soy milk was less viscous than the other products at lower concentrations. Replacement of corn meal and soy with vegetable oil produces less viscous porridges but reformulation would be needed to maintain protein and micronutrient levels. Significant process and formulation changes are needed in these products to increase their suitability for use as complementary foods. PMID:19449279

  14. A novel strain energy density algorithm for laser-induced micro-hollows

    NASA Astrophysics Data System (ADS)

    Çelen, Serap

    2015-07-01

    Mechanical adaptation and stability of implants are dependent on strain energy density algorithms of their surfaces. These applications are in their early stage, but theoretical predictions show us that we can manufacture very strong, flexible biomaterial surface which has a shock absorbing ability. Laser micro-machining is a clean tool for biomedical industry. The purpose of this manuscript is to consolidate a laser micro-machining method for imitating lotus effect on commercially pure titanium specimen surfaces and to develop a novel strain energy density algorithm. Novel 3D nelumbo leafs were prepared using a fiber laser (λ=1060 nm) with 200-250 ns pulse durations and optimum operation parameters were suggested.

  15. Two-Dimensional Mesoporous Carbon Electrode for High Energy Density Electrochemical Supercapacitors.

    PubMed

    Kalubarme, Ramchandra S; Park, Chan-Jin; Shirage, Parasharam M

    2015-02-01

    Mesoporous carbon (MPC) with highly textured, reproducible and uniform structure is prepared by silica-sol template assisted method, as new carbonaceous supercapacitor materials with high energy density. High resolution transmission electron microscopy studies revealed that the MPC consisted of textured structure of carbon on the sheets like domains and exhibited a specific surface area of 1412 m2 g-1. The symmetric supercapacitor of MPC exhibits an excellent cyclability over 5000 cycles and high energy density of 84.6 Wh kg-1, with a cell potential of 1.6 V and a large specific capacitance of 238 F g-1 in neutral electrolyte. The enhanced performance of the carbon material as a supercapacitor electrode is due to the synergetic effect possibly contributed from the fast ion transportation during fast charge/discharge and better utilization of carbon. PMID:26353641

  16. Large laser sparks for laboratory simulation of high-energy-density events in planetary atmospheres

    NASA Astrophysics Data System (ADS)

    Babankova, Dagmar; Juha, Libor; Civias, Svatopluk; Bittner, Michal; Cihelka, Jaroslav; Bartnik, Andrzej; Fiedorowicz, Henryk; Mikolajczyk, Janusz; Ryc, Leszek; Pfeifer, Miroslav; Skala, Jiri; Ullschmied, Jiri

    2005-09-01

    Single ≤1 kJ pulses from a high-power laser are focused into molecular gases to create large laser sparks. This provides a unique way to mimic the chemical effects of high-energy-density events in planetary atmospheres (cometary impact, lightning) matching the natural energy-density, its spatio-temporal evolution and plasma-volume scaling of such events in a fully-controlled laboratory environment. Some chemical reactions initiated by laser-induced dielectric breakdown (LIDB) in both pure molecular gases and mixtures related to the chemical evolution of the Earth's early atmosphere were studied. Most of the experiments were carried out in a static gas cell. However, an initial series of experiments was also performed with a gas-puff target placed within a vacuum interaction chamber. Under these dynamic conditions the hot core of a laser spark can be directly investigated.

  17. Orbital relaxation effects on Kohn–Sham frontier orbital energies in density functional theory

    SciTech Connect

    Zhang, DaDi; Zheng, Xiao; Li, Chen; Yang, Weitao

    2015-04-21

    We explore effects of orbital relaxation on Kohn–Sham frontier orbital energies in density functional theory by using a nonempirical scaling correction approach developed in Zheng et al. [J. Chem. Phys. 138, 174105 (2013)]. Relaxation of Kohn–Sham orbitals upon addition/removal of a fractional number of electrons to/from a finite system is determined by a systematic perturbative treatment. The information of orbital relaxation is then used to improve the accuracy of predicted Kohn–Sham frontier orbital energies by Hartree–Fock, local density approximation, and generalized gradient approximation methods. The results clearly highlight the significance of capturing the orbital relaxation effects. Moreover, the proposed scaling correction approach provides a useful way of computing derivative gaps and Fukui quantities of N-electron finite systems (N is an integer), without the need to perform self-consistent-field calculations for (N ± 1)-electron systems.

  18. Electron density compression and oscillating effects on laser energy absorption in overdense plasma targets.

    PubMed

    Ge, Z Y; Zhuo, H B; Yu, W; Yang, X H; Yu, T P; Li, X H; Zou, D B; Ma, Y Y; Yin, Y; Shao, F Q; Peng, X J

    2014-03-01

    An analytical model for energy absorption during the interaction of an ultrashort, ultraintense laser with an overdense plasma is proposed. Both the compression effect of the electron density profile and the oscillation of the electron plasma surface are self-consistently included, which exhibit significant influences on the laser energy absorption. Based on our model, the general scaling law of the compression effect depending on laser strength and initial density is derived, and the temporal variation of the laser absorption due to the boundary oscillating effect is presented. It is found that due to the oscillation of the electron plasma surface, the laser absorption rate will vibrate periodically at ω or 2ω frequency for the p-polarized and s-polarized laser, respectively. The effect of plasma collision on the laser absorption has also been investigated, which shows a considerable rise in absorption with increasing electron-ion collision frequency for both polarizations. PMID:24730955

  19. Multispecies Density and Temperature Gradient Dependence of Quasilinear Particle and Energy Fluxes

    SciTech Connect

    G. Rewoldt; R.V. Budny; W.M. Tang

    2004-08-09

    The variations of the normalized quasilinear particle and energy fluxes with artificial changes in the density and temperature gradients, as well as the variations of the linear growth rates and real frequencies, for ion temperature gradient and trapped-electron modes, are calculated. The quasilinear fluxes are normalized to the total energy flux, summed over all species. Here, realistic cases for tokamaks and spherical torii are considered which have two impurity species. For situations where there are substantial changes in the normalized fluxes, the ''diffusive approximation,'' in which the normalized fluxes are taken to be linear in the gradients, is seen to be inaccurate. Even in the case of small artificial changes in density or temperature gradients, changes in the fluxes of different species (''off-diagonal'') generally are significant, or even dominant, compared to those for the same species (''diagonal'').

  20. Fragment transition density method to calculate electronic coupling for excitation energy transfer

    SciTech Connect

    Voityuk, Alexander A.

    2014-06-28

    A general approach, the Fragment Transition Density (FTD) scheme, is introduced to estimate electronic coupling for excitation energy transfer in a molecular system. Within this method, the excitation energies and transition densities of the system are used to derive the coupling matrix element. The scheme allows one to treat systems where exciton donor and acceptor are close together and their exchange interaction and orbital overlap are significant. The FTD method can be applied in combination with any quantum mechanical approach to treat excited states of general nature including single-, double-, and higher excitations. Using FTD approach, we derive excitonic couplings for several systems computed with the CIS, TD DFT and MS-CASPT2 methods. In particular, it is shown that the estimated coupling values in DNA π-stacks are strongly affected by the short-range electronic interaction of adjacent nucleobases.

  1. High-energy side-peak emission of exciton-polariton condensates in high density regime

    PubMed Central

    Horikiri, Tomoyuki; Yamaguchi, Makoto; Kamide, Kenji; Matsuo, Yasuhiro; Byrnes, Tim; Ishida, Natsuko; Löffler, Andreas; Höfling, Sven; Shikano, Yutaka; Ogawa, Tetsuo; Forchel, Alfred; Yamamoto, Yoshihisa

    2016-01-01

    In a standard semiconductor laser, electrons and holes recombine via stimulated emission to emit coherent light, in a process that is far from thermal equilibrium. Exciton-polariton condensates–sharing the same basic device structure as a semiconductor laser, consisting of quantum wells coupled to a microcavity–have been investigated primarily at densities far below the Mott density for signatures of Bose-Einstein condensation. At high densities approaching the Mott density, exciton-polariton condensates are generally thought to revert to a standard semiconductor laser, with the loss of strong coupling. Here, we report the observation of a photoluminescence sideband at high densities that cannot be accounted for by conventional semiconductor lasing. This also differs from an upper-polariton peak by the observation of the excitation power dependence in the peak-energy separation. Our interpretation as a persistent coherent electron-hole-photon coupling captures several features of this sideband, although a complete understanding of the experimental data is lacking. A full understanding of the observations should lead to a development in non-equilibrium many-body physics. PMID:27193700

  2. High-energy side-peak emission of exciton-polariton condensates in high density regime

    NASA Astrophysics Data System (ADS)

    Horikiri, Tomoyuki; Yamaguchi, Makoto; Kamide, Kenji; Matsuo, Yasuhiro; Byrnes, Tim; Ishida, Natsuko; Löffler, Andreas; Höfling, Sven; Shikano, Yutaka; Ogawa, Tetsuo; Forchel, Alfred; Yamamoto, Yoshihisa

    2016-05-01

    In a standard semiconductor laser, electrons and holes recombine via stimulated emission to emit coherent light, in a process that is far from thermal equilibrium. Exciton-polariton condensates–sharing the same basic device structure as a semiconductor laser, consisting of quantum wells coupled to a microcavity–have been investigated primarily at densities far below the Mott density for signatures of Bose-Einstein condensation. At high densities approaching the Mott density, exciton-polariton condensates are generally thought to revert to a standard semiconductor laser, with the loss of strong coupling. Here, we report the observation of a photoluminescence sideband at high densities that cannot be accounted for by conventional semiconductor lasing. This also differs from an upper-polariton peak by the observation of the excitation power dependence in the peak-energy separation. Our interpretation as a persistent coherent electron-hole-photon coupling captures several features of this sideband, although a complete understanding of the experimental data is lacking. A full understanding of the observations should lead to a development in non-equilibrium many-body physics.

  3. High-energy side-peak emission of exciton-polariton condensates in high density regime.

    PubMed

    Horikiri, Tomoyuki; Yamaguchi, Makoto; Kamide, Kenji; Matsuo, Yasuhiro; Byrnes, Tim; Ishida, Natsuko; Löffler, Andreas; Höfling, Sven; Shikano, Yutaka; Ogawa, Tetsuo; Forchel, Alfred; Yamamoto, Yoshihisa

    2016-01-01

    In a standard semiconductor laser, electrons and holes recombine via stimulated emission to emit coherent light, in a process that is far from thermal equilibrium. Exciton-polariton condensates-sharing the same basic device structure as a semiconductor laser, consisting of quantum wells coupled to a microcavity-have been investigated primarily at densities far below the Mott density for signatures of Bose-Einstein condensation. At high densities approaching the Mott density, exciton-polariton condensates are generally thought to revert to a standard semiconductor laser, with the loss of strong coupling. Here, we report the observation of a photoluminescence sideband at high densities that cannot be accounted for by conventional semiconductor lasing. This also differs from an upper-polariton peak by the observation of the excitation power dependence in the peak-energy separation. Our interpretation as a persistent coherent electron-hole-photon coupling captures several features of this sideband, although a complete understanding of the experimental data is lacking. A full understanding of the observations should lead to a development in non-equilibrium many-body physics. PMID:27193700

  4. Feedback control of plasma electron density and ion energy in an inductively coupled plasma etcher

    SciTech Connect

    Lin Chaung; Leou, K.-C.; Huang, H.-M.; Hsieh, C.-H.

    2009-01-15

    Here the authors report the development of a fuzzy logic based feedback control of the plasma electron density and ion energy for high density plasma etch process. The plasma electron density was measured using their recently developed transmission line microstrip microwave interferometer mounted on the chamber wall, and the rf voltage was measured by a commercial impedance meter connected to the wafer stage. The actuators were two 13.56 MHz rf power generators which provided the inductively coupled plasma power and bias power, respectively. The control system adopted the fuzzy logic control algorithm to reduce frequent actuator action resulting from measurement noise. The experimental results show that the first wafer effect can be eliminated using closed-loop control for both poly-Si and HfO{sub 2} etching. In particular, for the HfO2 etch, the controlled variables in this work were much more effective than the previous one where ion current was controlled, instead of the electron density. However, the pressure disturbance effect cannot be reduced using plasma electron density feedback.

  5. The impact of Hall physics on magnetized high energy density plasma jetsa)

    NASA Astrophysics Data System (ADS)

    Gourdain, P.-A.; Seyler, C. E.; Atoyan, L.; Greenly, J. B.; Hammer, D. A.; Kusse, B. R.; Pikuz, S. A.; Potter, W. M.; Schrafel, P. C.; Shelkovenko, T. A.

    2014-05-01

    Hall physics is often neglected in high energy density plasma jets due to the relatively high electron density of such jets (ne ˜ 1019 cm-3). However, the vacuum region surrounding the jet has much lower densities and is dominated by Hall electric field. This electric field redirects plasma flows towards or away from the axis, depending on the radial current direction. A resulting change in the jet density has been observed experimentally. Furthermore, if an axial field is applied on the jet, the Hall effect is enhanced and ignoring it leads to serious discrepancies between experimental results and numerical simulations. By combining high currents (˜1 MA) and magnetic field helicity (15° angle) in a pulsed power generator such as COBRA, plasma jets can be magnetized with a 10 T axial field. The resulting field enhances the impact of the Hall effect by altering the density profile of current-free plasma jets and the stability of current-carrying plasma jets (e.g., Z-pinches).

  6. The impact of Hall physics on magnetized high energy density plasma jets

    SciTech Connect

    Gourdain, P.-A.; Seyler, C. E.; Atoyan, L.; Greenly, J. B.; Hammer, D. A.; Kusse, B. R.; Pikuz, S. A.; Potter, W. M.; Schrafel, P. C.; Shelkovenko, T. A.

    2014-05-15

    Hall physics is often neglected in high energy density plasma jets due to the relatively high electron density of such jets (n{sub e} ∼ 10{sup 19} cm{sup −3}). However, the vacuum region surrounding the jet has much lower densities and is dominated by Hall electric field. This electric field redirects plasma flows towards or away from the axis, depending on the radial current direction. A resulting change in the jet density has been observed experimentally. Furthermore, if an axial field is applied on the jet, the Hall effect is enhanced and ignoring it leads to serious discrepancies between experimental results and numerical simulations. By combining high currents (∼1 MA) and magnetic field helicity (15° angle) in a pulsed power generator such as COBRA, plasma jets can be magnetized with a 10 T axial field. The resulting field enhances the impact of the Hall effect by altering the density profile of current-free plasma jets and the stability of current-carrying plasma jets (e.g., Z-pinches)

  7. Superconductivity, cohesive energy density, and electron-atom ratio in metals

    NASA Technical Reports Server (NTRS)

    England, C.; Lawson, D. D.; Hrubes, J. D.

    1981-01-01

    It is shown that superconductivity above 8 K occurs in alloys and metallic compounds within relatively narrow regions of cohesive energy density with a sharp peak which includes Nb3Ge, SiV3, Nb3Ga, and NbN. When cross-correlated with the electron-atom ratio, high-temperature superconductivity can be observed in only a few regions. This suggests a search for superconductors with high-transition temperatures and critical fields within these regions.

  8. Neutron-star matter within the energy-density functional theory and neutron-star structure

    SciTech Connect

    Fantina, A. F.; Chamel, N.; Goriely, S.; Pearson, J. M.

    2015-02-24

    In this lecture, we will present some nucleonic equations of state of neutron-star matter calculated within the nuclear energy-density functional theory using generalized Skyrme functionals developed by the Brussels-Montreal collaboration. These equations of state provide a consistent description of all regions of a neutron star. The global structure of neutron stars predicted by these equations of state will be discussed in connection with recent astrophysical observations.

  9. Nuclear energy density functionals: What we can learn about/from their global performance?

    SciTech Connect

    Afanasjev, A. V.; Agbemava, S. E.; Ray, D.; Ring, P.

    2014-10-15

    A short review of recent results on the global performance of covariant energy density functionals is presented. It is focused on an analysis of the accuracy of the description of physical observables of ground and excited states as well as to related theoretical uncertainties. In addition, a global analysis of pairing properties is presented and the impact of pairing on the position of two-neutron drip line is discussed.

  10. High-density capacitors pack more energy in a smaller space

    NASA Astrophysics Data System (ADS)

    Lerner, E. J.

    1985-05-01

    Attention is given to the design features and performance characteristics of novel high density capacitor banks which furnish a tenfold energy increase over conventional capacitors, to values of the order of 100 J/kg or 0.28 J/cu cm. The essential feature of the new design is the replacement of plastic dielectric films interleaved with oil-soaked films by a paperless film system that uses perfluorocarbon rather than oil.

  11. Development of low-cost, compact, reliable, high energy density ceramic nanocomposite capacitors.

    SciTech Connect

    Cooley, Erika J.; Monson, Todd C.; DiAntonio, Christopher Brian; Huber, Dale L.; Fellows, Benjamin D.; Stevens, Tyler E.; Roesler, Alexander William; Chavez, Tom P.; Winter, Michael R.

    2010-05-01

    The ceramic nanocomposite capacitor goals are: (1) more than double energy density of ceramic capacitors (cutting size and weight by more than half); (2) potential cost reductino (factor of >4) due to decreased sintering temperature (allowing the use of lower cost electrode materials such as 70/30 Ag/Pd); and (3) lower sintering temperature will allow co-firing with other electrical components.

  12. Defect-Engineered Graphene for High-Energy- and High-Power-Density Supercapacitor Devices.

    PubMed

    Zhu, Jingyi; Childress, Anthony S; Karakaya, Mehmet; Dandeliya, Sushmita; Srivastava, Anurag; Lin, Ye; Rao, Apparao M; Podila, Ramakrishna

    2016-09-01

    Defects are often written off as performance limiters. Contrary to this notion, it is shown that controlling the defect configuration in graphene is critical to overcome a fundamental limitation posed by quantum capacitance and opens new channels for ion diffusion. Defect-engineered graphene flexible pouch capacitors with energy densities of 500% higher than the state-of-the-art supercapacitors are demonstrated. PMID:27299300

  13. A high-energy-density redox flow battery based on zinc/polyhalide chemistry.

    PubMed

    Zhang, Liqun; Lai, Qinzhi; Zhang, Jianlu; Zhang, Huamin

    2012-05-01

    Zn and the Art of Battery Development: A zinc/polyhalide redox flow battery employs Br(-) /ClBr(2-) and Zn/Zn(2+) redox couples in its positive and negative half-cells, respectively. The performance of the battery is evaluated by charge-discharge cycling tests and reveals a high energy efficiency of 81%, based on a Coulombic efficiency of 96% and voltage efficiency of 84%. The new battery technology can provide high performance and energy density at an acceptable cost. PMID:22262638

  14. The high-energy-density counterpropagating shear experiment and turbulent self-heating

    SciTech Connect

    Doss, F. W.; Fincke, J. R.; Loomis, E. N.; Welser-Sherrill, L.; Flippo, K. A.

    2013-12-15

    The counterpropagating shear experiment has previously demonstrated the ability to create regions of shock-driven shear, balanced symmetrically in pressure, and experiencing minimal net drift. This allows for the creation of a high-Mach-number high-energy-density shear environment. New data from the counterpropagating shear campaign is presented, and both hydrocode modeling and theoretical analysis in the context of a Reynolds-averaged-Navier-Stokes model suggest turbulent dissipation of energy from the supersonic flow bounding the layer is a significant driver in its expansion. A theoretical minimum shear flow Mach number threshold is suggested for substantial thermal-turbulence coupling.

  15. Differential heating: A versatile method for thermal conductivity measurements in high-energy-density matter

    DOE PAGESBeta

    Ping, Y.; Fernandez-Panella, A.; Sio, H.; Correa, A.; Shepherd, R.; Landen, O.; London, R. A.; Sterne, P. A.; Whitley, H. D.; Fratanduono, D.; et al

    2015-09-04

    We propose a method for thermal conductivity measurements of high energy density matter based on differential heating. A temperature gradient is created either by surface heating of one material or at an interface between two materials by different energy deposition. The subsequent heat conduction across the temperature gradient is observed by various time-resolved probing techniques. Conceptual designs of such measurements using laser heating, proton heating, and x-ray heating are presented. As a result, the sensitivity of the measurements to thermal conductivity is confirmed by simulations.

  16. High-energy spin-density-wave correlated fluctuations in paramagnetic Cr + 5 at. % V

    SciTech Connect

    Werner, S.A.; Fawcett, E.; Elmiger, M.W.; Shirane, G.

    1992-11-01

    Measurements of the magnetic fluctuations, termed spin-density-wave (SDW) paramagnons, in the nearly antiferromagnetic alloy Cr + 5 at.%V are extended up in energy to about 80 MeV. These fluctuating spin-spin correlations occur at incommensurate positions, corresponding to the SDW wavevector Q. Their characteristic energy is at least an order of magnitude larger than that of the magnetic fluctuations seen in the paramagnetic phase of pure Cr, but their intensity is more than two orders of magnitude smaller. We find that the dynamic susceptibility decreases by about 50% between temperature T = 10K and 300K.

  17. High-energy spin-density-wave correlated fluctuations in paramagnetic Cr + 5 at. % V

    SciTech Connect

    Werner, S.A. . Dept. of Physics); Fawcett, E. . Dept. of Physics); Elmiger, M.W.; Shirane, G. )

    1992-01-01

    Measurements of the magnetic fluctuations, termed spin-density-wave (SDW) paramagnons, in the nearly antiferromagnetic alloy Cr + 5 at.%V are extended up in energy to about 80 MeV. These fluctuating spin-spin correlations occur at incommensurate positions, corresponding to the SDW wavevector Q. Their characteristic energy is at least an order of magnitude larger than that of the magnetic fluctuations seen in the paramagnetic phase of pure Cr, but their intensity is more than two orders of magnitude smaller. We find that the dynamic susceptibility decreases by about 50% between temperature T = 10K and 300K.

  18. Folding paper-based lithium-ion batteries for higher areal energy densities.

    PubMed

    Cheng, Qian; Song, Zeming; Ma, Teng; Smith, Bethany B; Tang, Rui; Yu, Hongyu; Jiang, Hanqing; Chan, Candace K

    2013-10-01

    Paper folding techniques are used in order to compact a Li-ion battery and increase its energy per footprint area. Full cells were prepared using Li4Ti5O12 and LiCoO2 powders deposited onto current collectors consisting of paper coated with carbon nanotubes. Folded cells showed higher areal capacities compared to the planar versions with a 5 × 5 cell folded using the Miura-ori pattern displaying a ~14× increase in areal energy density. PMID:24059538

  19. Relativistic Energy Density Functionals: beyond mean-field description of exotic structures

    SciTech Connect

    Vretenar, D.; Niksic, T.; Ring, P.; Lalazissis, G. A.

    2009-01-28

    The framework of relativistic energy density functionals is extended to include correlations related to the restoration of broken symmetries and to fluctuations of collective variables. The generator coordinate method is used to perform configuration mixing of angular-momentum and particle-number projected relativistic wave functions. This approach enables a quantitative description of the evolution of shell-structure, deformation and shape coexistence phenomena in nuclei with soft potential energy surfaces, and singular properties of excitation spectra and transition rates at critical points of quantum shape phase transitions.

  20. Interacting boson model from energy density functionals: {gamma}-softness and the related topics

    SciTech Connect

    Nomura, K.

    2012-10-20

    A comprehensive way of deriving the Hamiltonian of the interacting boson model (IBM) is described. Based on the fact that the multi-nucleon induced surface deformation in finite nucleus is simulated by effective boson degrees of freedom, the potential energy surface calculated with self-consistent mean-field method employing a given energy density functional (EDF) is mapped onto the IBM analog, and thereby the excitation spectra and transition rates with good symmetry quantum numbers are calculated. Recent applications of the proposed approach are reported: (i) an alternative robust interpretation of the {gamma}-soft nuclei and (ii) shape coexistence in lead isotopes.

  1. Stabilizing laser energy density on a target during pulsed laser deposition of thin films

    DOEpatents

    Dowden, Paul C.; Jia, Quanxi

    2016-05-31

    A process for stabilizing laser energy density on a target surface during pulsed laser deposition of thin films controls the focused laser spot on the target. The process involves imaging an image-aperture positioned in the beamline. This eliminates changes in the beam dimensions of the laser. A continuously variable attenuator located in between the output of the laser and the imaged image-aperture adjusts the energy to a desired level by running the laser in a "constant voltage" mode. The process provides reproducibility and controllability for deposition of electronic thin films by pulsed laser deposition.

  2. Modern energy density functional and the current status of the equation of state of nuclear matter

    SciTech Connect

    Shlomo, S.

    2012-11-20

    We first describe a method, based on the simulated annealing approach, for determining a modern energy density functional within the Skyrme Hartree-Fock (HF) theory by carrying out a fit to extensive set of experimental data with additional constraints on the Skyrme parameters. Next, we review the HF-based random phase approximation (RPA) approach for calculating properties of giant resonances. We then present results of calculations for the centroid energies of giant resonances within the HF-based RPA and discuss the current status of the equation of state of nuclear matter.

  3. The high-energy-density counterpropagating shear experiment and turbulent self-heating

    DOE PAGESBeta

    Doss, F. W.; Fincke, J. R.; Loomis, E. N.; Welser-Sherrill, L.; Flippo, K. A.

    2013-12-06

    The counterpropagating shear experiment has previously demonstrated the ability to create regions of shockdriven shear, balanced symmetrically in pressure and experiencing minimal net drift. This allows for the creation of a high-Mach-number high-energy-density shear environment. New data from the counterpropagating shear campaign is presented, and both hydrocode modeling and theoretical analysis in the context of a Reynolds-averaged-Navier-Stokes model suggest turbulent dissipation of energy from the supersonic flow bounding the layer is a significant driver in its expansion. A theoretical minimum shear flow Mach number threshold is suggested for substantial thermal-turbulence coupling.

  4. Differential heating: A versatile method for thermal conductivity measurements in high-energy-density matter

    SciTech Connect

    Ping, Y.; Fernandez-Panella, A.; Correa, A.; Shepherd, R.; Landen, O.; London, R. A.; Sterne, P. A.; Whitley, H. D.; Fratanduono, D.; Collins, G. W.; Sio, H.; Boehly, T. R.

    2015-09-15

    We propose a method for thermal conductivity measurements of high energy density matter based on differential heating. A temperature gradient is created either by surface heating of one material or at an interface between two materials by different energy deposition. The subsequent heat conduction across the temperature gradient is observed by various time-resolved probing techniques. Conceptual designs of such measurements using laser heating, proton heating, and x-ray heating are presented. The sensitivity of the measurements to thermal conductivity is confirmed by simulations.

  5. Using Density Functional Theory (DFT) for the Calculation of Atomization Energies

    NASA Technical Reports Server (NTRS)

    Bauschlicher, Charles W., Jr.; Partridge, Harry; Langhoff, Stephen R. (Technical Monitor)

    1995-01-01

    The calculation of atomization energies using density functional theory (DFT), using the B3LYP hybrid functional, is reported. The sensitivity of the atomization energy to basis set is studied and compared with the coupled cluster singles and doubles approach with a perturbational estimate of the triples (CCSD(T)). Merging the B3LYP results with the G2(MP2) approach is also considered. It is found that replacing the geometry optimization and calculation of the zero-point energy by the analogous quantities computed using the B3LYP approach reduces the maximum error in the G2(MP2) approach. In addition to the 55 G2 atomization energies, some results for transition metal containing systems will also be presented.

  6. Modern energy density functional for nuclei and the nuclear matter equation of state

    SciTech Connect

    Shlomo, S.

    2010-08-15

    We discuss a method of determining a modern energy density functional (EDF) in nuclei. We adopt a Skyrme type EDF and fit the Skyrme parameters to an extensive set of experimental data on the ground-state binding energies, radii, and the breathing mode energies of a wide range of nuclei. We further constrain the values of the Skyrme parameters by requiring positive values for the slope of the symmetry energy S, the enhancement factor {kappa}, associated with the isovector giant dipole resonance, and the Landau parameter G{sub 0}{sup '}. This is done within the approaches of Hartree-Fock (HF) and HF with the inclusion of correlation effects, using a simulated-annealing based algorithm forminimizing {chi}{sup 2}.We also present results of HF based random phase approximation for the excitation strength function of the breathing mode and discuss the current status of the nuclear matter incompressibility coefficient.

  7. A Microelectromechanical High-Density Energy Storage/Rapid Release System

    SciTech Connect

    Rodgers, M. Steven; Allen, Jim J.; Meeks, Kent D.; Jensen, Brian D.; Miller, Sam L.

    1999-07-21

    One highly desirable characteristic of electrostatically driven microelectromechanical systems (MEMS) is that they consume very little power. The corresponding drawback is that the force they produce may be inadequate for many applications. It has previously been demonstrated that gear reduction units or microtransmissions can substantially increase the torque generated by microengines. Operating speed, however, is also reduced by the transmission gear ratio. Some applications require both high speed and high force. If this output is only required for a limited period of time, then energy could be stored in a mechanical system and rapidly released upon demand. We have designed, fabricated, and demonstrated a high-density energy storage/rapid release system that accomplishes this task. Built using a 5-level surface micromachining technology, the assembly closely resembles a medieval crossbow. Energy releases on the order of tens of nanojoules have already been demonstrated, and significantly higher energy systems are under development.

  8. Dietary energy density in the dry period on the metabolic status of lactating cows.

    PubMed

    Nowak, W; Mikula, R; Pruszyńska-Oszmalek, E; Maćkowiak, P; Stefańska, B; Kasprowicz-Potocka, M; Frankiewicz, A; Drzazga, K

    2013-01-01

    The aim of the study was to investigate the effect of different energy concentrations in the isonitrogenous diet fed during the dry period on postpartum health, fertility and blood variables. Forty Holstein multiparous cows were dried 56 days before the expected day of calving and assigned to group (M) with moderate energy concentrations of 0.69 UFL/kg DM or to the low-energy group (L) with energy density of 0.61 UFL/kg DM. From the 7d before the expected day of calving until the 21d of lactation, all the cows were fed the same fresh transition diet (0.82 UFL/kg DM). From the 22d to the 90d of lactation, all the cows received the same highest energy-density lactation diet (0.90 UFL/kg DM). During the dry period the decline of BCS in groups M and L were 0.07 and 0.12 units respectively. The average decrease of BCS from calving to 56 d of lactation were the same in both experimental groups (0.21 BCS). The first-service conception rate tended to be higher in the M group. Insulin-like growth factor-1, glucose, beta-hydroxybutyric acid, non-esterified fatty acid, thyroxine serum concentrations prepartum and 3 and 5d postpartum were not significantly affected by the treatment in the dry period. PMID:24597307

  9. Simulation of electron energy loss spectra of nanomaterials with linear-scaling density functional theory.

    PubMed

    Tait, E W; Ratcliff, L E; Payne, M C; Haynes, P D; Hine, N D M

    2016-05-18

    Experimental techniques for electron energy loss spectroscopy (EELS) combine high energy resolution with high spatial resolution. They are therefore powerful tools for investigating the local electronic structure of complex systems such as nanostructures, interfaces and even individual defects. Interpretation of experimental electron energy loss spectra is often challenging and can require theoretical modelling of candidate structures, which themselves may be large and complex, beyond the capabilities of traditional cubic-scaling density functional theory. In this work, we present functionality to compute electron energy loss spectra within the onetep linear-scaling density functional theory code. We first demonstrate that simulated spectra agree with those computed using conventional plane wave pseudopotential methods to a high degree of precision. The ability of onetep to tackle large problems is then exploited to investigate convergence of spectra with respect to supercell size. Finally, we apply the novel functionality to a study of the electron energy loss spectra of defects on the (1 0 1) surface of an anatase slab and determine concentrations of defects which might be experimentally detectable. PMID:27094207

  10. Visualizing fast electron energy transport into laser-compressed high-density fast-ignition targets

    NASA Astrophysics Data System (ADS)

    Jarrott, L. C.; Wei, M. S.; McGuffey, C.; Solodov, A. A.; Theobald, W.; Qiao, B.; Stoeckl, C.; Betti, R.; Chen, H.; Delettrez, J.; Döppner, T.; Giraldez, E. M.; Glebov, V. Y.; Habara, H.; Iwawaki, T.; Key, M. H.; Luo, R. W.; Marshall, F. J.; McLean, H. S.; Mileham, C.; Patel, P. K.; Santos, J. J.; Sawada, H.; Stephens, R. B.; Yabuuchi, T.; Beg, F. N.

    2016-05-01

    Recent progress in kilojoule-scale high-intensity lasers has opened up new areas of research in radiography, laboratory astrophysics, high-energy-density physics, and fast-ignition (FI) laser fusion. FI requires efficient heating of pre-compressed high-density fuel by an intense relativistic electron beam produced from laser-matter interaction. Understanding the details of electron beam generation and transport is crucial for FI. Here we report on the first visualization of fast electron spatial energy deposition in a laser-compressed cone-in-shell FI target, facilitated by doping the shell with copper and imaging the K-shell radiation. Multi-scale simulations accompanying the experiments clearly show the location of fast electrons and reveal key parameters affecting energy coupling. The approach provides a more direct way to infer energy coupling and guide experimental designs that significantly improve the laser-to-core coupling to 7%. Our findings lay the groundwork for further improving efficiency, with 15% energy coupling predicted in FI experiments using an existing megajoule-scale laser driver.

  11. Simulation of electron energy loss spectra of nanomaterials with linear-scaling density functional theory

    NASA Astrophysics Data System (ADS)

    Tait, E. W.; Ratcliff, L. E.; Payne, M. C.; Haynes, P. D.; Hine, N. D. M.

    2016-05-01

    Experimental techniques for electron energy loss spectroscopy (EELS) combine high energy resolution with high spatial resolution. They are therefore powerful tools for investigating the local electronic structure of complex systems such as nanostructures, interfaces and even individual defects. Interpretation of experimental electron energy loss spectra is often challenging and can require theoretical modelling of candidate structures, which themselves may be large and complex, beyond the capabilities of traditional cubic-scaling density functional theory. In this work, we present functionality to compute electron energy loss spectra within the onetep linear-scaling density functional theory code. We first demonstrate that simulated spectra agree with those computed using conventional plane wave pseudopotential methods to a high degree of precision. The ability of onetep to tackle large problems is then exploited to investigate convergence of spectra with respect to supercell size. Finally, we apply the novel functionality to a study of the electron energy loss spectra of defects on the (1 0 1) surface of an anatase slab and determine concentrations of defects which might be experimentally detectable.

  12. Density of States for Warped or non-Warped Energy Bands

    NASA Astrophysics Data System (ADS)

    Mecholsky, Nicholas; Resca, Lorenzo; Pegg, Ian; Fornari, Marco

    The goal of this talk is to investigate when band warping affects density-of-states effective mass. Further, band ``corrugation,'' a form of band warping referring to energy dispersions that deviate ``more severely'' from being twice-differentiable at isolated critical points, may also correlate in different ways with density-of-states effective masses and other band warping parameters. In this talk, an angular effective mass formalism is developed and used to study the electronic density of states of warped and non-warped energy bands towards an application in thermoelectric transport design. We demonstrate effects of band warping and prove the superiority of the angular effective mass treatment for valence energy bands in cubic materials. We explore examples that can also be critical to precisely distinguish the contributions due to band warping and to band non-parabolicity in non-degenerate bands of thermoelectric materials that have a consequent practical interest. The presenter wished to thank the Vitreous State Laboratory.

  13. Theory and High-Energy-Density Laser Experiments Relevant to Accretion Processes in Cataclysmic Variables

    NASA Astrophysics Data System (ADS)

    Krauland, Christine; Drake, R.; Loupias, B.; Falize, E.; Busschaert, C.; Ravasio, A.; Yurchak, R.; Pelka, A.; Koenig, M.; Kuranz, C. C.; Plewa, T.; Huntington, C. M.; Kaczala, D. N.; Klein, S.; Sweeney, R.; Villete, B.; Young, R.; Keiter, P. A.

    2012-05-01

    We present results from high-energy-density (HED) laboratory experiments that explore the contribution of radiative shock waves to the evolving dynamics of the cataclysmic variable (CV) systems in which they reside. CVs can be classified under two main categories, non-magnetic and magnetic. In the process of accretion, both types involve strongly radiating shocks that provide the main source of radiation in the binary systems. This radiation can cause varying structure to develop depending on the optical properties of the material on either side of the shock. The ability of high-intensity lasers to create large energy densities in targets of millimeter-scale volume makes it feasible to create similar radiative shocks in the laboratory. We provide an overview of both CV systems and their connection to the designed and executed laboratory experiments preformed on two laser facilities. Available data and accompanying simulations will likewise be shown. Funded by the NNSA-DS and SC-OFES Joint Prog. in High-Energy-Density Lab. Plasmas, by the Nat. Laser User Facility Prog. in NNSA-DS and by the Predictive Sci. Acad. Alliances Prog. in NNSA-ASC, under grant numbers are DE-FG52-09NA29548, DE-FG52-09NA29034, and DE-FC52-08NA28616.

  14. Development of high energy density fuels from mild gasification of coal

    SciTech Connect

    Not Available

    1990-10-01

    The overall objective of the program is the determination of the minimal processing requirements to produce High Energy Density Fuels (HEDF), meeting a minimal energy density of 130,000 Btu/gal (conventional jet fuels have energy densities in the vicinity of 115,000--120,000 Btu/gal) and having acceptable advanced fuel specifications in accordance with the three defined categories of HEDF. The program encompasses assessing current technology capability; selecting acceptable processing and refining schemes; and generating samples of advanced test fuels. A task breakdown structure was developed containing eight key tasks. This report summarizes the work that Amoco Oil Company (AOC), as key subcontractor, performed in the execution of Task 4, Proposed Upgrading Schemes for Advanced Fuel. The intent of the Task 4 study was to represent all the candidate processing options, that were either studied in the experimental efforts of Task 3 or were available from the prior art in the open literature, in a linear program (LP) model. The LP model would allow scaling of the bench-scale Task 3 results to commercial scale and would perform economic evaluations on any combination of the processes which might be used to make HEDF. Section 2.0 of this report summarizes the process and economic bases used. Sections 3.0 and 4.0 details the economics and processing sensitivities for HEDF production. 1 ref., 15 figs., 9 tabs.

  15. Poynting vector, energy densities, and pressure of collective transverse electromagnetic fluctuations in unmagnetized plasmas

    SciTech Connect

    Schlickeiser, R.

    2012-01-15

    A systematic calculation of the electromagnetic properties (Poynting vector, electromagnetic energy, and pressure) of the collective transverse fluctuations in unmagnetized plasmas with velocity-anisotropic plasma particle distributions functions is presented. Time-averaged electromagnetic properties for monochromatic weakly damped wave-like fluctuations and space-averaged electromagnetic properties for monochromatic weakly propagating and aperiodic fluctuations are calculated. For aperiodic fluctuations, the Poynting vector as well as the sum of the space-averaged electric and magnetic field energy densities vanish. However, aperiodic fluctuations possess a positive pressure given by its magnetic energy density. This finite pressure density p{sub a} of aperiodic fluctuations has important consequences for the dynamics of cosmic unmagnetized plasmas such as the intergalactic medium after reionization. Adopting the standard cosmological evolution model, we show that this additional pressure changes the expansion law of the universe leading to further deceleration. Negative vacuum pressure counterbalances this deceleration to an accelerating universe provided that the negative vacuum pressure is greater than 1.5p{sub a}, which we estimate to be of the order 2.1 {center_dot} 10{sup -16} dyn cm{sup -2}.

  16. The cohesive energy density and the isothermal compressibility: Their relationships with the surface tension

    NASA Astrophysics Data System (ADS)

    Aqra, Fathi

    2014-08-01

    Models for predicting the cohesive energy density (CeD), the isothermal compressibility (kT), the compressibility and surface tension product (kT.γ), the ratio of surface tension to cohesive energy density (γ/CeD) and the isothermal compressibility and cohesive energy density product (kT.CeD) are described. The temperature T at which the numerical constants are valid is the melting temperature. The studies are being restricted to alkali halides. The calculated (kT.γ) values (21.3-40.9 pm), pertained to the sizes of voids between the ions, are of a smaller range than in the earlier treatments and agree very well with the experimental published data (21.9-47.6 pm). The determined (γ/CeD) values (4.3-8.2 pm), attributed to the contraction of the internuclear distance of the top-layer atoms in the surface, are comparable with the experimental data (3.9-11 pm). It is found that the ratio of the internuclear distance at the surface to that of the bulk is 97-98%.

  17. Ru/Al Multilayers Integrate Maximum Energy Density and Ductility for Reactive Materials

    NASA Astrophysics Data System (ADS)

    Woll, K.; Bergamaschi, A.; Avchachov, K.; Djurabekova, F.; Gier, S.; Pauly, C.; Leibenguth, P.; Wagner, C.; Nordlund, K.; Mücklich, F.

    2016-01-01

    Established and already commercialized energetic materials, such as those based on Ni/Al for joining, lack the adequate combination of high energy density and ductile reaction products. To join components, this combination is required for mechanically reliable bonds. In addition to the improvement of existing technologies, expansion into new fields of application can also be anticipated which triggers the search for improved materials. Here, we present a comprehensive characterization of the key parameters that enables us to classify the Ru/Al system as new reactive material among other energetic systems. We finally found that Ru/Al exhibits the unusual integration of high energy density and ductility. For example, we measured reaction front velocities up to 10.9 (±0.33) ms-1 and peak reaction temperatures of about 2000 °C indicating the elevated energy density. To our knowledge, such high temperatures have never been reported in experiments for metallic multilayers. In situ experiments show the synthesis of a single-phase B2-RuAl microstructure ensuring improved ductility. Molecular dynamics simulations corroborate the transformation behavior to RuAl. This study fundamentally characterizes a Ru/Al system and demonstrates its enhanced properties fulfilling the identification requirements of a novel nanoscaled energetic material.

  18. Lattice vibrations in the Frenkel-Kontorova model. I. Phonon dispersion, number density, and energy

    DOE PAGESBeta

    Meng, Qingping; Wu, Lijun; Welch, David O.; Zhu, Yimei

    2015-06-17

    We studied the lattice vibrations of two inter-penetrating atomic sublattices via the Frenkel-Kontorova (FK) model of a linear chain of harmonically interacting atoms subjected to an on-site potential, using the technique of thermodynamic Green's functions based on quantum field-theoretical methods. General expressions were deduced for the phonon frequency-wave-vector dispersion relations, number density, and energy of the FK model system. In addition, as the application of the theory, we investigated in detail cases of linear chains with various periods of the on-site potential of the FK model. Some unusual but interesting features for different amplitudes of the on-site potential of themore » FK model are discussed. In the commensurate structure, the phonon spectrum always starts at a finite frequency, and the gaps of the spectrum are true ones with a zero density of modes. In the incommensurate structure, the phonon spectrum starts from zero frequency, but at a non-zero wave vector; there are some modes inside these gap regions, but their density is very low. In our approximation, the energy of a higher-order commensurate state of the one-dimensional system at a finite temperature may become indefinitely close to the energy of an incommensurate state. This finding implies that the higher-order incommensurate-commensurate transitions are continuous ones and that the phase transition may exhibit a “devil's staircase” behavior at a finite temperature.« less

  19. Ru/Al Multilayers Integrate Maximum Energy Density and Ductility for Reactive Materials

    PubMed Central

    Woll, K.; Bergamaschi, A.; Avchachov, K.; Djurabekova, F.; Gier, S.; Pauly, C.; Leibenguth, P.; Wagner, C.; Nordlund, K.; Mücklich, F.

    2016-01-01

    Established and already commercialized energetic materials, such as those based on Ni/Al for joining, lack the adequate combination of high energy density and ductile reaction products. To join components, this combination is required for mechanically reliable bonds. In addition to the improvement of existing technologies, expansion into new fields of application can also be anticipated which triggers the search for improved materials. Here, we present a comprehensive characterization of the key parameters that enables us to classify the Ru/Al system as new reactive material among other energetic systems. We finally found that Ru/Al exhibits the unusual integration of high energy density and ductility. For example, we measured reaction front velocities up to 10.9 (±0.33) ms−1 and peak reaction temperatures of about 2000 °C indicating the elevated energy density. To our knowledge, such high temperatures have never been reported in experiments for metallic multilayers. In situ experiments show the synthesis of a single-phase B2-RuAl microstructure ensuring improved ductility. Molecular dynamics simulations corroborate the transformation behavior to RuAl. This study fundamentally characterizes a Ru/Al system and demonstrates its enhanced properties fulfilling the identification requirements of a novel nanoscaled energetic material. PMID:26822309

  20. Lattice vibrations in the Frenkel-Kontorova model. I. Phonon dispersion, number density, and energy

    NASA Astrophysics Data System (ADS)

    Meng, Qingping; Wu, Lijun; Welch, David O.; Zhu, Yimei

    2015-06-01

    We studied the lattice vibrations of two interpenetrating atomic sublattices via the Frenkel-Kontorova (FK) model of a linear chain of harmonically interacting atoms subjected to an on-site potential using the technique of thermodynamic Green's functions based on quantum field-theoretical methods. General expressions were deduced for the phonon frequency-wave-vector dispersion relations, number density, and energy of the FK model system. As the application of the theory, we investigated in detail cases of linear chains with various periods of the on-site potential of the FK model. Some unusual but interesting features for different amplitudes of the on-site potential of the FK model are discussed. In the commensurate structure, the phonon spectrum always starts at a finite frequency, and the gaps of the spectrum are true ones with a zero density of modes. In the incommensurate structure, the phonon spectrum starts from zero frequency, but at a nonzero wave vector; there are some modes inside these gap regions, but their density is very low. In our approximation, the energy of a higher-order commensurate state of the one-dimensional system at a finite temperature may become indefinitely close to the energy of an incommensurate state. This finding implies that the higher-order incommensurate-commensurate transitions are continuous ones and that the phase transition may exhibit a "devil's staircase" behavior at a finite temperature.

  1. Lattice vibrations in the Frenkel-Kontorova model. I. Phonon dispersion, number density, and energy

    SciTech Connect

    Meng, Qingping; Wu, Lijun; Welch, David O.; Zhu, Yimei

    2015-06-17

    We studied the lattice vibrations of two inter-penetrating atomic sublattices via the Frenkel-Kontorova (FK) model of a linear chain of harmonically interacting atoms subjected to an on-site potential, using the technique of thermodynamic Green's functions based on quantum field-theoretical methods. General expressions were deduced for the phonon frequency-wave-vector dispersion relations, number density, and energy of the FK model system. In addition, as the application of the theory, we investigated in detail cases of linear chains with various periods of the on-site potential of the FK model. Some unusual but interesting features for different amplitudes of the on-site potential of the FK model are discussed. In the commensurate structure, the phonon spectrum always starts at a finite frequency, and the gaps of the spectrum are true ones with a zero density of modes. In the incommensurate structure, the phonon spectrum starts from zero frequency, but at a non-zero wave vector; there are some modes inside these gap regions, but their density is very low. In our approximation, the energy of a higher-order commensurate state of the one-dimensional system at a finite temperature may become indefinitely close to the energy of an incommensurate state. This finding implies that the higher-order incommensurate-commensurate transitions are continuous ones and that the phase transition may exhibit a “devil's staircase” behavior at a finite temperature.

  2. Comparison of Energy Efficiency and Power Density in Pressure Retarded Osmosis and Reverse Electrodialysis

    SciTech Connect

    Yip, NY; Elimelech, M

    2014-09-16

    Pressure retarded osmosis (PRO) and reverse electrodialysis (RED) are emerging membrane-based technologies that can convert chemical energy in salinity gradients to useful work. The two processes have intrinsically different working principles: controlled mixing in PRO is achieved by water permeation across salt-rejecting membranes, whereas RED is driven by ion flux across charged membranes. This study compares the energy efficiency and power density performance of PRO and RED with simulated technologically available membranes for natural, anthropogenic, and engineered salinity gradients (seawater-river water, desalination brine-wastewater, and synthetic hypersaline solutions, respectively). The analysis shows that PRO can achieve both greater efficiencies (54-56%) and higher power densities (2.4-38 W/m(2)) than RED (18-38% and 0.77-1.2 W/m(2)). The superior efficiency is attributed to the ability of PRO membranes to more effectively utilize the salinity difference to drive water permeation and better suppress the detrimental leakage of salts. On the other hand, the low conductivity of currently available ion exchange membranes impedes RED ion flux and, thus, constrains the power density. Both technologies exhibit a trade-off between efficiency and power density: employing more permeable but less selective membranes can enhance the power density, but undesired entropy production due to uncontrolled mixing increases and some efficiency is sacrificed. When the concentration difference is increased (i.e., natural -> anthropogenic -> engineered salinity gradients), PRO osmotic pressure difference rises proportionally but not so for RED Nernst potential, which has logarithmic dependence on the solution concentration. Because of this inherently different characteristic, RED is unable to take advantage of larger salinity gradients, whereas PRO power density is considerably enhanced. Additionally, high solution concentrations suppress the Donnan exclusion effect of the

  3. Comparison of energy efficiency and power density in pressure retarded osmosis and reverse electrodialysis.

    PubMed

    Yip, Ngai Yin; Elimelech, Menachem

    2014-09-16

    Pressure retarded osmosis (PRO) and reverse electrodialysis (RED) are emerging membrane-based technologies that can convert chemical energy in salinity gradients to useful work. The two processes have intrinsically different working principles: controlled mixing in PRO is achieved by water permeation across salt-rejecting membranes, whereas RED is driven by ion flux across charged membranes. This study compares the energy efficiency and power density performance of PRO and RED with simulated technologically available membranes for natural, anthropogenic, and engineered salinity gradients (seawater-river water, desalination brine-wastewater, and synthetic hypersaline solutions, respectively). The analysis shows that PRO can achieve both greater efficiencies (54-56%) and higher power densities (2.4-38 W/m(2)) than RED (18-38% and 0.77-1.2 W/m(2)). The superior efficiency is attributed to the ability of PRO membranes to more effectively utilize the salinity difference to drive water permeation and better suppress the detrimental leakage of salts. On the other hand, the low conductivity of currently available ion exchange membranes impedes RED ion flux and, thus, constrains the power density. Both technologies exhibit a trade-off between efficiency and power density: employing more permeable but less selective membranes can enhance the power density, but undesired entropy production due to uncontrolled mixing increases and some efficiency is sacrificed. When the concentration difference is increased (i.e., natural → anthropogenic → engineered salinity gradients), PRO osmotic pressure difference rises proportionally but not so for RED Nernst potential, which has logarithmic dependence on the solution concentration. Because of this inherently different characteristic, RED is unable to take advantage of larger salinity gradients, whereas PRO power density is considerably enhanced. Additionally, high solution concentrations suppress the Donnan exclusion effect of the

  4. Mapping the energy density of shaped waves in scattering media onto a complete set of diffusion modes.

    PubMed

    Ojambati, Oluwafemi S; Mosk, Allard P; Vellekoop, Ivo M; Lagendijk, Ad; Vos, Willem L

    2016-08-01

    We study the energy density of shaped waves inside a quasi-1D disordered waveguide. We find that the spatial energy density of optimally shaped waves, when expanded in the complete set of eigenfunctions of the diffusion equation, is well described by considering only a few of the lowest eigenfunctions. Taking into account only the fundamental eigenfunction, the total internal energy inside the sample is underestimated by only 2%. The spatial distribution of the shaped energy density is very similar to the fundamental eigenfunction, up to a cosine distance of about 0.01. We obtain the energy density of transmission eigenchannels inside the sample by numerical simulation of the scattering matrix. Computing the transmission-averaged energy density over all transmission channels yields the ensemble averaged energy density of shaped waves. From the averaged energy density, we reconstruct its spatial distribution using the eigenfunctions of the diffusion equation. The results of our study have exciting applications in controlled biomedical imaging, efficient light harvesting in solar cells, enhanced energy conversion in solid-state lighting, and low threshold random lasers. PMID:27505816

  5. Laser driven high energy density radiative blast waves launched in clustered gases

    NASA Astrophysics Data System (ADS)

    Olsson-Robbie, Stefan; Doyle, Hugo; Lowe, Hazel; Price, Chris; Bigourd, Damien; Patankar, Siddharth; Mecseki, Katalin; Booth, Nicola; Scott, Robbie; Moore, Alastair; Hohenberger, Matthias; Rodriguez, Rafael; Gumbrell, Edward; Symes, Daniel; Smith, Roland

    2012-10-01

    Intense lasers deposit energy efficiently in clustered gases creating hot plasma with low density, conditions ideal for launching radiative blast waves (BWs) of interest for laboratory astrophysics (LA). We report measurements in a range of gases irradiated by the Astra-Gemini laser with energies >10J. Optical imaging, self emission and temporally resolved x-ray spectra are used to characterise BW evolution. The high repetition rate of the laser allows us to explore the influence of atomic number and density on the BW dynamics. Altering the emitted radiation and opacity of the medium has a strong effect on the BW profile and energy loss. Strongly radiative BWs exhibit shell thinning, increasing their susceptibility to instabilities. We have demonstrated the onset of a velocity instability, driven by the exchange of energy between the shock and precursor in krypton BWs. We discuss the threshold conditions for this behaviour and the potential to study spatial shock front instabilities. Our results will be compared to simulations and analytical calculations with a view to designing scalable LA experiments.

  6. Constraining the high-density nuclear symmetry energy with the transverse-momentum-dependent elliptic flow

    NASA Astrophysics Data System (ADS)

    Wang, Yongjia; Guo, Chenchen; Li, Qingfeng; Zhang, Hongfei; Leifels, Y.; Trautmann, W.

    2014-04-01

    Within the newly updated version of the ultrarelativistic quantum molecular dynamics (UrQMD) model, the transverse-velocity dependence of the elliptic flow of free nucleons from Au197+Au197 collisions at the incident energy 400 MeV/nucleon is studied within different windows of the normalized c.m. rapidity y0. It is found that the elliptic flow difference v2n-v2p and ratio v2n/v2p of neutrons versus protons are sensitive to the density dependence of the symmetry energy, especially the ratio v2n/v2p at small transverse velocity in the intermediate rapidity intervals 0.4<|y0|<0.6. By comparing either transverse-momentum-dependent or integrated FOPI/LAND elliptic flow data of nucleons and hydrogen isotopes with calculations using various Skyrme interactions, all exhibiting similar values of isoscalar incompressibility but very different density dependences of the symmetry energy, a moderately soft to linear symmetry energy is extracted, in good agreement with previous UrQMD or Tübingen QMD model calculations but contrast with results obtained with π-/π+ yield ratios in the literature.

  7. Generalized acoustic energy density based active noise control in single frequency diffuse sound fields.

    PubMed

    Xu, Buye; Sommerfeldt, Scott D

    2014-09-01

    In a diffuse sound field, prior research has established that a secondary source can theoretically achieve perfect cancellation at an error microphone in the far field of the secondary source. However, the sound pressure level is generally only reduced in a small zone around the error sensor, and at a distance half of a wavelength away from the error sensor, the averaged sound pressure level will be increased by more than 10 dB. Recently an acoustic energy quantity, referred to as the generalized acoustic energy density (GED), has been introduced. The GED is obtained by using a weighting factor in the formulation of total acoustic energy density. Different values of the weighting factor can be chosen for different applications. When minimizing the GED at the error sensor, one can adjust the weighting factor to increase the spatial extent of the "quiet zone" and to achieve a desired balance between the degree of attenuation in the quiet zone and the total energy added into the sound field. PMID:25190386

  8. Modeling and simulations of diphasic composites for development of high energy density dielectrics

    NASA Astrophysics Data System (ADS)

    Patil, Sandeep Kesharsingh

    This doctoral research is focused on analytical and numerical modeling of diphasic composites for use in high energy density capacitors for pulsed power applications. An analytical model is presented based on an equivalent capacitance/impedance circuit used to express the effective permittivity of a composite dielectric with complex-shaped inclusions as functions of frequency and inclusion volume fraction. Zero-three (0-3) types of composites are investigated using this model. The results of this model are compared with different known effective medium theories (Maxwell Garnett, logarithmic, Bruggeman, series, and parallel mixing rules). Model predictions are also compared with published experimental data and are found to be in good agreement. Electrostatic field distribution characteristics and energy storage magnitudes for diphasic dielectrics containing high-permittivity inclusions in a low permittivity host phase (0-3 composite) have been evaluated analytically and numerically. Field distribution and energy storage were studied as a function of dielectric contrast (ratio of inclusion to host permittivity) and inclusion volume fraction. Information obtained from these studies was used to consider optimized diphasic dielectric traits that would lead to increases in energy density and breakdown behavior. Results of these simulations were also compared to the Maxwell Garnett (MG) mixing rule and the upper limit of applicability of the MG formulation in terms of inclusion volume fraction was established. It was determined that this limit was a function of the dielectric contrast.

  9. A low cost, high energy density and long cycle life potassium-sulfur battery for grid-scale energy storage

    SciTech Connect

    Lu, Xiaochuan; Bowden, Mark E.; Sprenkle, Vincent L.; Liu, Jun

    2015-08-15

    Alkali metal-sulfur batteries are attractive for energy storage applications because of their high energy density. Among the batteries, lithium-sulfur batteries typically use liquid in the battery electrolyte, which causes problems in both performance and safety. Sodium-sulfur batteries can use a solid electrolyte such as beta alumina but this requires a high operating temperature. Here we report a novel potassium-sulfur battery with K+-conducting beta-alumina as the electrolyte. Our studies indicate that liquid potassium exhibits much better wettability on the surface of beta-alumina compared to liquid sodium at lower temperatures. Based on this observation, we develop a potassium-sulfur battery that can operate at as low as 150°C with excellent performance. In particular, the battery shows excellent cycle life with negligible capacity fade in 1000 cycles because of the dense ceramic membrane. This study demonstrates a new battery with a high energy density, long cycle life, low cost and high safety, which is ideal for grid-scale energy storage.

  10. High Energy Density Thermal Batteries: Thermoelectric Reactors for Efficient Automotive Thermal Storage

    SciTech Connect

    2011-11-15

    HEATS Project: Sheetak is developing a new HVAC system to store the energy required for heating and cooling in EVs. This system will replace the traditional refrigerant-based vapor compressors and inefficient heaters used in today’s EVs with efficient, light, and rechargeable hot-and-cold thermal batteries. The high energy density thermal battery—which does not use any hazardous substances—can be recharged by an integrated solid-state thermoelectric energy converter while the vehicle is parked and its electrical battery is being charged. Sheetak’s converters can also run on the electric battery if needed and provide the required cooling and heating to the passengers—eliminating the space constraint and reducing the weight of EVs that use more traditional compressors and heaters.

  11. Organic semiconductor density of states controls the energy level alignment at electrode interfaces

    PubMed Central

    Oehzelt, Martin; Koch, Norbert; Heimel, Georg

    2014-01-01

    Minimizing charge carrier injection barriers and extraction losses at interfaces between organic semiconductors and metallic electrodes is critical for optimizing the performance of organic (opto-) electronic devices. Here, we implement a detailed electrostatic model, capable of reproducing the alignment between the electrode Fermi energy and the transport states in the organic semiconductor both qualitatively and quantitatively. Covering the full phenomenological range of interfacial energy level alignment regimes within a single, consistent framework and continuously connecting the limiting cases described by previously proposed models allows us to resolve conflicting views in the literature. Our results highlight the density of states in the organic semiconductor as a key factor. Its shape and, in particular, the energy distribution of electronic states tailing into the fundamental gap is found to determine both the minimum value of practically achievable injection barriers as well as their spatial profile, ranging from abrupt interface dipoles to extended band-bending regions. PMID:24938867

  12. Energetic multifunctionalized nitraminopyrazoles and their ionic derivatives: ternary hydrogen-bond induced high energy density materials.

    PubMed

    Yin, Ping; Parrish, Damon A; Shreeve, Jean'ne M

    2015-04-15

    Diverse functionalization was introduced into the pyrazole framework giving rise to a new family of ternary hydrogen-bond induced high energy density materials. By incorporating extended cationic interactions, nitramine-based ionic derivatives exhibit good energetic performance and enhanced molecular stability. Performance parameters including heats of formation and detonation properties were calculated by using Gaussian 03 and EXPLO5 v6.01 programs, respectively. It is noteworthy to find that 5-nitramino-3,4-dinitropyrazole, 4, has a remarkable measured density of 1.97 g cm(-3) at 298 K, which is consistent with its crystal density (2.032 g cm(-3), 150 K), and ranks highest among azole-based CHNO compounds. Energetic evaluation indicates that, in addition to the molecular compound 4, some ionic derivatives, 9, 11, 12, 17, 19, and 22, also have high densities (1.83-1.97 g cm(-3)), excellent detonation pressures and velocities (P, 35.6-41.6 GPa; vD, 8880-9430 m s(-1)), as well as acceptable impact and friction sensitivities (IS, 4-30 J; FS, 40-240 N). These attractive features highlight the application potential of nitramino hydrogen-bonded interactions in the design of advanced energetic materials. PMID:25807076

  13. Measurements of turbulent mixing due to Kelvin-Helmholtz instability in high-energy-density plasmas

    NASA Astrophysics Data System (ADS)

    Smalyuk, V. A.; Hurricane, O. A.; Hansen, J. F.; Langstaff, G.; Martinez, D.; Park, H.-S.; Raman, K.; Remington, B. A.; Robey, H. F.; Schilling, O.; Wallace, R.; Elbaz, Y.; Shimony, A.; Shvarts, D.; Di Stefano, C.; Drake, R. P.; Marion, D.; Krauland, C. M.; Kuranz, C. C.

    2013-03-01

    Kelvin-Helmholtz (KH) turbulent mixing measurements were performed in experiments on the OMEGA Laser Facility [T.R. Boehly et al., Opt. Commun. 133 (1997) 495]. In these experiments, laser-driven shock waves propagated through low-density plastic foam placed on top of a higher-density plastic foil. Behind the shock front, lower-density foam plasma flowed over the higher-density plastic plasma. The interface between the foam and plastic was KH unstable. The experiments were performed with pre-imposed, sinusoidal 2D perturbations, and broadband 3D perturbations due to surface roughness at the interface between the plastic and foam. KH instability growth was measured using X-ray, point-projection radiography. The mixing layer caused by the KH instability with layer width up to ˜100 μm was observed at a location ˜1 mm behind the shock front. The measured mixing layer width was in good agreement with simulations using a K-L turbulent mixing model in the two-dimensional ARES hydrodynamics code. In the definition of the K-L model K stands for the specific turbulent kinetic (K) energy, and L for the scale length (L) of the turbulence.

  14. Density functional theory for low-energy electron-molecule scattering

    NASA Astrophysics Data System (ADS)

    Burke, Kieron; Wasserman, Adam

    2004-09-01

    Time-dependent density functional theory (TDDFT) is becoming popular as an approach to time-dependent electronic problems[1]. In the weak field regime, TDDFT predicts electronic transition frequencies and optical spectra of atoms, molecules, clusters, and solids, with an accuracy comparable to high-level wavefunction calculations at a fraction of the computational cost[2]. For large systems, TDDFT is the method of choice. Given the importance of correlation effects in low-energy electron-molecule scattering, extracting scattering amplitudes from TDDFT appears desirable. I will review this background, and outline how this can be done[3]. Detailed results will be shown by Wasserman in another talk. [1] Time-Dependent Density Functional Theory, M.A.L. Marques and E.K.U. Gross, Annu. Rev. Phys. Chem. 55, 427 (2004). [2] Time-dependent density functional theory in quantum chemistry, F. Furche and K. Burke, to appear in 1st vol. of Annu. Rev. of Computational Chemistry (2004) [3] Electron-molecule scattering from time-dependent density functional theory A. Wasserman, N.T. Maitra, and K. Burke, submitted (see http:dft.rutgers.edu/pubs/publist.html).

  15. Measurements of the Electron Cloud Density in the PEP-II Low Energy Ring

    SciTech Connect

    Byrd, John; De Santis, Stefano; Sonnad, Kiran; Caspers, Fritz; Kroyer, Tom; Krasnykh, Anatoly; Pivi, Mauro

    2008-06-01

    Clouds of low energy electronsin the vacuum beam pipes of accelerators of positively charged particle beams present a serious limitation for operation of these machines at high currents. Because of the size of these accelerators, it is difficult to probe the low energyelectron clouds over substantial lengths of the beam pipe. We have developed a novel technique to directly measure the electron cloud density via the phase shift induced in a TE wave that is independently excited and transmitted over a section of the accelerator. We infer the absolute phase shift with relatively high accuracy from the phase modulation of the transmission due to the modulation of the electron cloud density from a gap in the positively charged beam. We have used this technique for the first time to measure the average electron cloud density over a 50 m straight section in the positron ring of the PEP-II collider at the Stanford Linear Accelerator Center. We have also measured the variation of the density by using low field solenoid magnets to control the electrons.

  16. Effects of dietary lysine and energy density on performance and carcass characteristics of finishing pigs fed ractopamine.

    PubMed

    Apple, J K; Maxwell, C V; Brown, D C; Friesen, K G; Musser, R E; Johnson, Z B; Armstrong, T A

    2004-11-01

    Two hundred sixteen crossbred barrows and gilts (84.3 kg BW) were used to test the effects of dietary energy density and lysine:energy ratio (Lys:ME) on the performance, carcass characteristics, and pork quality of finishing pigs fed 10 ppm ractopamine. Pigs were blocked by BW and gender, allotted to 36 pens (six pigs per pen), and pens were assigned randomly within blocks to dietary treatments (as-fed basis) arranged in a 2 x 3 factorial design, with two levels of energy (3.30 or 3.48 Mcal/kg) and three Lys:ME (1.7, 2.4, or 3.1 g lysine/Mcal) levels. Pigs were fed experimental diets for 28 d, and weights and feed disappearance were recorded weekly to calculate ADG, ADFI, and G:F. Upon completion of the feeding trial, pigs were slaughtered and carcass data were collected before fabrication. During carcass fabrication, hams were analyzed for lean composition using a ham electrical conductivity (TOBEC) unit, and loins were collected, vacuum-packaged, and boxed for pork quality data collection. Energy density had no (P > 0.22) effect on ADG or ADFI across the entire 28-d feeding trial; however, pigs fed 3.48 Mcal of ME were more (P < 0.02) efficient than pigs fed 3.30 Mcal of ME. In addition, ADG and G:F increased linearly (P < 0.01) as Lys:ME increased from 1.7 to 3.1 g/Mcal. Carcasses of pigs fed 3.48 Mcal of ME were fatter at the last lumbar vertebrae (P < 0.08) and 10th rib (P < 0.04), resulting in a lower (P < 0.03) predicted fat-free lean yield (FFLY). Conversely, 10th-rib fat thickness decreased linearly (P = 0.02), and LM depth (P < 0.01) and area (P < 0.01) increased linearly, with increasing Lys:ME. Moreover, FFLY (P < 0.01) and actual ham lean yield (P < 0.01) increased as Lys:ME increased in the diet. Dietary energy density had no (P > 0.19) effect on pork quality, and Lys:ME did not (P > 0.20) affect muscle pH, drip loss, color, and firmness scores. Marbling scores, as well as LM lipid content, decreased linearly (P < 0.01) as Lys:ME increased from 1.7 to

  17. On the Elastic Energy Density of Constrained Q-Tensor Models for Biaxial Nematics

    NASA Astrophysics Data System (ADS)

    Mucci, Domenico; Nicolodi, Lorenzo

    2012-12-01

    Within the Landau-de Gennes theory, the order parameter describing a biaxial nematic liquid crystal assigns a symmetric traceless 3 × 3 matrix Q with three distinct eigenvalues to every point of the region Ω occupied by the system. In the constrained case of matrices Q with constant eigenvalues, the order parameter space is diffeomorphic to the eightfold quotient {{S}^3/{H}} of the 3-sphere {{S}^3}, where {{H}} is the quaternion group, and a configuration of a biaxial nematic liquid crystal is described by a map from Ω to {{S}^3/{H}}. We express the (simplest form of the) Landau-de Gennes elastic free-energy density as a density defined on maps {q: Ω to {S}^3}, whose functional dependence is restricted by the requirements that (1) it is well defined on the class of configuration maps from Ω to {{S}^3/{H}} (residual symmetry) and (2) it is independent of arbitrary superposed rigid rotations (frame indifference). As an application of this representation, we then discuss some properties of the corresponding energy functional, including coercivity, lower semicontinuity and strong density of smooth maps. Other invariance properties are also considered. In the discussion, we take advantage of the identification of {{S}^3} with the Lie group of unit quaternions {Sp(1) \\cong SU(2)} and of the relations between quaternions and rotations in {{R}^3} and {{R}^4}.

  18. Hypovalency--a kinetic-energy density description of a 4c-2e bond.

    PubMed

    Jacobsen, Heiko

    2009-06-01

    A bond descriptor based on the kinetic energy density, the localized-orbital locator (LOL), is used to characterize the nature of the chemical bond in electron deficient multi-center bonds. The boranes B(2)H(6), B(4)H(4), B(4)H(10), [B(6)H(6)](2-), and [B(6)H(7)](-) serve as prototypical examples of hypovalent 3c-2e and 4c-2e bonding. The kinetic energy density is derived from a set of Kohn-Sham orbitals obtained from pure density functional calculations (PBE/TZVP), and the topology of LOL is analyzed in terms of (3,-3) attractors (Gamma). The B-B-B and B-H-B 3c-2e, and the B-B-H-B 4c-2e bonding situations are defined by their own characteristic LOL profiles. The presence of one attractor in relation to the three or four atoms that are engaged in electron deficient bonding provides sufficient indication of the type of 3c-2e or 4c-2e bond present. For the 4c-2e bond in [B(6)H(7)](-) the LOL analysis is compared to results from an experimental QTAIM study. PMID:19452076

  19. Density slope of the nuclear symmetry energy from the neutron skin thickness of heavy nuclei

    SciTech Connect

    Chen Liewen; Ko Che Ming; Xu Jun; Li Baoan

    2010-08-15

    Expressing explicitly the parameters of the standard Skyrme interaction in terms of the macroscopic properties of asymmetric nuclear matter, we show in the Skyrme-Hartree-Fock approach that unambiguous correlations exist between observables of finite nuclei and nuclear matter properties. We find that existing data on neutron skin thickness {Delta}r{sub np} of Sn isotopes give an important constraint on the symmetry energy E{sub sym}({rho}{sub 0}) and its density slope L at saturation density {rho}{sub 0}. Combining these constraints with those from recent analyses of isospin diffusion and the double neutron/proton ratio in heavy-ion collisions at intermediate energies leads to a more stringent limit on L approximately independent of E{sub sym}({rho}{sub 0}). The implication of these new constraints on the {Delta}r{sub np} of {sup 208}Pb as well as the core-crust transition density and pressure in neutron stars is discussed.

  20. Novel LLM series high density energy materials: Synthesis, characterization, and thermal stability

    NASA Astrophysics Data System (ADS)

    Pagoria, Philip; Zhang, Maoxi; Tsyshevskiy, Roman; Kuklja, Maija

    Novel high density energy materials must satisfy specific requirements, such as an increased performance, reliably high stability to external stimuli, cost-efficiency and ease of synthesis, be environmentally benign, and be safe for handling and transportation. During the last decade, the attention of researchers has drifted from widely used nitroester-, nitramine-, and nitroaromatic-based explosives to nitrogen-rich heterocyclic compounds. Good thermal stability, the low melting point, high density, and moderate sensitivity make heterocycle materials attractive candidates for use as oxidizers in rocket propellants and fuels, secondary explosives, and possibly as melt-castable ingredients of high explosive formulations. In this report, the synthesis, characterization, and results of quantum-chemical DFT study of thermal stability of LLM-191, LLM-192 and LLM-200 high density energy materials are presented. Work performed under the auspices of the DOE by the LLNL (Contract DE-AC52-07NA27344). This research is supported in part by ONR (Grant N00014-12-1-0529) and NSF. We used NSF XSEDE (Grant DMR-130077) and DOE NERSC (Contract DE-AC02-05CH11231) resources.