Science.gov

Sample records for acoustic energy density

  1. Directional Acoustic Density Sensor

    DTIC Science & Technology

    2010-09-13

    fluctuations of fluid density at a point . (2) DESCRIPTION OF THE PRIOR ART [0004] Conventional vector sensors measure particle velocity, v (vx,Vytvz...dipole-type or first order sensor that is realized by measuring particle velocity at a point , (which is the vector sensor sensing approach for...underwater sensors), or by measuring the gradient of the acoustic pressure at two closely spaced (less than the wavelength of an acoustic wave) points as it

  2. Characterization of intense ion beam energy density and beam induced pressure on the target with acoustic diagnostics

    SciTech Connect

    Pushkarev, A. I.; Isakova, Yu. I.; Khailov, I. P.; Yu, Xiao

    2013-08-15

    We have developed the acoustic diagnostics based on a piezoelectric transducer for characterization of high-intensity pulsed ion beams. The diagnostics was tested using the TEMP-4M accelerator (150 ns, 250–300 kV). The beam is composed of C{sup +} ions (85%) and protons, the beam energy density is 0.5–5 J/cm{sup 2} (depending on diode geometry). A calibration dependence of the signal from a piezoelectric transducer on the ion beam energy density is obtained using thermal imaging diagnostics. It is shown that the acoustic diagnostics allows for measurement of the beam energy density in the range of 0.1–2 J/cm{sup 2}. The dependence of the beam generated pressure on the input energy density is also determined and compared with the data from literature. The developed acoustic diagnostics do not require sophisticated equipment and can be used for operational control of pulsed ion beam parameters with a repetition rate of 10{sup 3} pulses/s.

  3. On the statistical errors in the estimate of acoustical energy density by using two microphones in a one dimensional field.

    PubMed

    Pascal, Jean-Claude; Thomas, Jean-Hugh; Li, Jing-Fang

    2008-10-01

    It was recently shown that the statistical errors of the measurement in the acoustic energy density by the two microphone method in waveguide have little variation when the losses of coherence between microphones increase. To explain these intervals of uncertainty, the variance of the measurement is expressed in this paper as a function of the various energy quantities of the acoustic fields--energy densities and sound intensities. The necessary conditions to reach the lower bound are clarified. The results obtained are illustrated by an example of a one-dimensional partially coherent field, which allows one to specify the relationship between the coherence functions of the pressure and particle velocity and those of the two microphone signals.

  4. Acoustic energy harvesting based on a planar acoustic metamaterial

    NASA Astrophysics Data System (ADS)

    Qi, Shuibao; Oudich, Mourad; Li, Yong; Assouar, Badreddine

    2016-06-01

    We theoretically report on an innovative and practical acoustic energy harvester based on a defected acoustic metamaterial (AMM) with piezoelectric material. The idea is to create suitable resonant defects in an AMM to confine the strain energy originating from an acoustic incidence. This scavenged energy is converted into electrical energy by attaching a structured piezoelectric material into the defect area of the AMM. We show an acoustic energy harvester based on a meta-structure capable of producing electrical power from an acoustic pressure. Numerical simulations are provided to analyze and elucidate the principles and the performances of the proposed system. A maximum output voltage of 1.3 V and a power density of 0.54 μW/cm3 are obtained at a frequency of 2257.5 Hz. The proposed concept should have broad applications on energy harvesting as well as on low-frequency sound isolation, since this system acts as both acoustic insulator and energy harvester.

  5. Acoustic energy in ducts - Further observations

    NASA Technical Reports Server (NTRS)

    Eversman, W.

    1979-01-01

    The transmission of acoustic energy in uniform ducts carrying uniform flow is investigated with the purpose of clarifying two points of interest. The two commonly used definitions of acoustic 'energy' flux are shown to be related by a Legendre transformation of the Lagrangian density exactly as in deriving the Hamiltonian density in mechanics. In the acoustic case the total energy density and the Hamiltonian density are not the same which accounts for two different 'energy' fluxes. When the duct has acoustically absorptive walls neither of the two flux expressions gives correct results. A reevaluation of the basis of derivation of the energy density and energy flux provides forms which yield consistent results for soft walled ducts.

  6. Acoustic Force Density Acting on Inhomogeneous Fluids in Acoustic Fields

    NASA Astrophysics Data System (ADS)

    Karlsen, Jonas T.; Augustsson, Per; Bruus, Henrik

    2016-09-01

    We present a theory for the acoustic force density acting on inhomogeneous fluids in acoustic fields on time scales that are slow compared to the acoustic oscillation period. The acoustic force density depends on gradients in the density and compressibility of the fluid. For microfluidic systems, the theory predicts a relocation of the inhomogeneities into stable field-dependent configurations, which are qualitatively different from the horizontally layered configurations due to gravity. Experimental validation is obtained by confocal imaging of aqueous solutions in a glass-silicon microchip.

  7. Acoustic metamaterials with circular sector cavities and programmable densities.

    PubMed

    Akl, W; Elsabbagh, A; Baz, A

    2012-10-01

    Considerable interest has been devoted to the development of various classes of acoustic metamaterials that can control the propagation of acoustical wave energy throughout fluid domains. However, all the currently exerted efforts are focused on studying passive metamaterials with fixed material properties. In this paper, the emphasis is placed on the development of a class of composite one-dimensional acoustic metamaterials with effective densities that are programmed to adapt to any prescribed pattern along the metamaterial. The proposed acoustic metamaterial is composed of a periodic arrangement of cell structures, in which each cell consists of a circular sector cavity bounded by actively controlled flexible panels to provide the capability for manipulating the overall effective dynamic density. The theoretical analysis of this class of multilayered composite active acoustic metamaterials (CAAMM) is presented and the theoretical predictions are determined for a cascading array of fluid cavities coupled to flexible piezoelectric active boundaries forming the metamaterial domain with programmable dynamic density. The stiffness of the piezoelectric boundaries is electrically manipulated to control the overall density of the individual cells utilizing the strong coupling with the fluid domain and using direct acoustic pressure feedback. The interaction between the neighboring cells of the composite metamaterial is modeled using a lumped-parameter approach. Numerical examples are presented to demonstrate the performance characteristics of the proposed CAAMM and its potential for generating prescribed spatial and spectral patterns of density variation.

  8. Estimating animal population density using passive acoustics.

    PubMed

    Marques, Tiago A; Thomas, Len; Martin, Stephen W; Mellinger, David K; Ward, Jessica A; Moretti, David J; Harris, Danielle; Tyack, Peter L

    2013-05-01

    Reliable estimation of the size or density of wild animal populations is very important for effective wildlife management, conservation and ecology. Currently, the most widely used methods for obtaining such estimates involve either sighting animals from transect lines or some form of capture-recapture on marked or uniquely identifiable individuals. However, many species are difficult to sight, and cannot be easily marked or recaptured. Some of these species produce readily identifiable sounds, providing an opportunity to use passive acoustic data to estimate animal density. In addition, even for species for which other visually based methods are feasible, passive acoustic methods offer the potential for greater detection ranges in some environments (e.g. underwater or in dense forest), and hence potentially better precision. Automated data collection means that surveys can take place at times and in places where it would be too expensive or dangerous to send human observers. Here, we present an overview of animal density estimation using passive acoustic data, a relatively new and fast-developing field. We review the types of data and methodological approaches currently available to researchers and we provide a framework for acoustics-based density estimation, illustrated with examples from real-world case studies. We mention moving sensor platforms (e.g. towed acoustics), but then focus on methods involving sensors at fixed locations, particularly hydrophones to survey marine mammals, as acoustic-based density estimation research to date has been concentrated in this area. Primary among these are methods based on distance sampling and spatially explicit capture-recapture. The methods are also applicable to other aquatic and terrestrial sound-producing taxa. We conclude that, despite being in its infancy, density estimation based on passive acoustic data likely will become an important method for surveying a number of diverse taxa, such as sea mammals, fish, birds

  9. Estimating animal population density using passive acoustics

    PubMed Central

    Marques, Tiago A; Thomas, Len; Martin, Stephen W; Mellinger, David K; Ward, Jessica A; Moretti, David J; Harris, Danielle; Tyack, Peter L

    2013-01-01

    Reliable estimation of the size or density of wild animal populations is very important for effective wildlife management, conservation and ecology. Currently, the most widely used methods for obtaining such estimates involve either sighting animals from transect lines or some form of capture-recapture on marked or uniquely identifiable individuals. However, many species are difficult to sight, and cannot be easily marked or recaptured. Some of these species produce readily identifiable sounds, providing an opportunity to use passive acoustic data to estimate animal density. In addition, even for species for which other visually based methods are feasible, passive acoustic methods offer the potential for greater detection ranges in some environments (e.g. underwater or in dense forest), and hence potentially better precision. Automated data collection means that surveys can take place at times and in places where it would be too expensive or dangerous to send human observers. Here, we present an overview of animal density estimation using passive acoustic data, a relatively new and fast-developing field. We review the types of data and methodological approaches currently available to researchers and we provide a framework for acoustics-based density estimation, illustrated with examples from real-world case studies. We mention moving sensor platforms (e.g. towed acoustics), but then focus on methods involving sensors at fixed locations, particularly hydrophones to survey marine mammals, as acoustic-based density estimation research to date has been concentrated in this area. Primary among these are methods based on distance sampling and spatially explicit capture-recapture. The methods are also applicable to other aquatic and terrestrial sound-producing taxa. We conclude that, despite being in its infancy, density estimation based on passive acoustic data likely will become an important method for surveying a number of diverse taxa, such as sea mammals, fish, birds

  10. Acoustic sensors using microstructures tunable with energy other than acoustic energy

    DOEpatents

    Datskos, Panagiotis G.

    2003-11-25

    A sensor for detecting acoustic energy includes a microstructure tuned to a predetermined acoustic frequency and a device for detecting movement of the microstructure. A display device is operatively linked to the movement detecting device. When acoustic energy strikes the acoustic sensor, acoustic energy having a predetermined frequency moves the microstructure, where the movement is detected by the movement detecting device.

  11. Acoustic sensors using microstructures tunable with energy other than acoustic energy

    DOEpatents

    Datskos, Panagiotis G.

    2005-06-07

    A sensor for detecting acoustic energy includes a microstructure tuned to a predetermined acoustic frequency and a device for detecting movement of the microstructure. A display device is operatively linked to the movement detecting device. When acoustic energy strikes the acoustic sensor, acoustic energy having a predetermined frequency moves the microstructure, where the movement is detected by the movement detecting device.

  12. Holographic Dark Energy Density

    NASA Astrophysics Data System (ADS)

    Saadat, Hassan

    2011-06-01

    In this article we consider the cosmological model based on the holographic dark energy. We study dark energy density in Universe with arbitrary spatially curvature described by the Friedmann-Robertson-Walker metric. We use Chevallier-Polarski-Linder parametrization to specify dark energy density.

  13. Bird population density estimated from acoustic signals

    USGS Publications Warehouse

    Dawson, D.K.; Efford, M.G.

    2009-01-01

    Many animal species are detected primarily by sound. Although songs, calls and other sounds are often used for population assessment, as in bird point counts and hydrophone surveys of cetaceans, there are few rigorous methods for estimating population density from acoustic data. 2. The problem has several parts - distinguishing individuals, adjusting for individuals that are missed, and adjusting for the area sampled. Spatially explicit capture-recapture (SECR) is a statistical methodology that addresses jointly the second and third parts of the problem. We have extended SECR to use uncalibrated information from acoustic signals on the distance to each source. 3. We applied this extension of SECR to data from an acoustic survey of ovenbird Seiurus aurocapilla density in an eastern US deciduous forest with multiple four-microphone arrays. We modelled average power from spectrograms of ovenbird songs measured within a window of 0??7 s duration and frequencies between 4200 and 5200 Hz. 4. The resulting estimates of the density of singing males (0??19 ha -1 SE 0??03 ha-1) were consistent with estimates of the adult male population density from mist-netting (0??36 ha-1 SE 0??12 ha-1). The fitted model predicts sound attenuation of 0??11 dB m-1 (SE 0??01 dB m-1) in excess of losses from spherical spreading. 5.Synthesis and applications. Our method for estimating animal population density from acoustic signals fills a gap in the census methods available for visually cryptic but vocal taxa, including many species of bird and cetacean. The necessary equipment is simple and readily available; as few as two microphones may provide adequate estimates, given spatial replication. The method requires that individuals detected at the same place are acoustically distinguishable and all individuals vocalize during the recording interval, or that the per capita rate of vocalization is known. We believe these requirements can be met, with suitable field methods, for a significant

  14. Method and apparatus for generating acoustic energy

    DOEpatents

    Guerrero, Hector N.

    2002-01-01

    A method and apparatus for generating and emitting amplified coherent acoustic energy. A cylindrical transducer is mounted within a housing, the transducer having an acoustically open end and an acoustically closed end. The interior of the transducer is filled with an active medium which may include scattering nuclei. Excitation of the transducer produces radially directed acoustic energy in the active medium, which is converted by the dimensions of the transducer, the acoustically closed end thereof, and the scattering nuclei, to amplified coherent acoustic energy directed longitudinally within the transducer. The energy is emitted through the acoustically open end of the transducer. The emitted energy can be used for, among other things, effecting a chemical reaction or removing scale from the interior walls of containment vessels.

  15. Energy in density gradient

    SciTech Connect

    Vranjes, J.; Kono, M.

    2015-01-15

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

  16. 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.

  17. Density-near-zero using the acoustically induced transparency of a Fano acoustic resonator

    NASA Astrophysics Data System (ADS)

    Elayouch, A.; Addouche, M.; Farhat, M.; Amin, M.; Bağcı, H.; Khelif, A.

    2016-11-01

    We report experimental results of near-zero mass density involving an acoustic metamaterial supporting Fano resonance. For this, we designed and fabricated an acoustic resonator with two closely coupled modes and measured its transmission properties. Our study reveals that the phenomenon of acoustically induced transparency is accompanied by an effect of near-zero density. Indeed, the dynamic effective parameters obtained from experimental data show the presence of a frequency band where the effective mass density is close to zero, with high transmission levels reaching 0.7. Furthermore, we demonstrate that such effective parameters lead to wave guiding in a 90-degrees-bent channel. This kind of acoustic metamaterial can, therefore, give rise to acoustic functions like controlling the wavefront, which may lead to very promising applications in acoustic cloacking or imaging.

  18. Density-dependent acoustic properties of PBX 9502

    SciTech Connect

    Brown, Geoffrey W; Thompson, Darla G; Deluca, Racci; Hartline, Ernest L; Hagelberg, Stephanie I

    2009-07-31

    We have measured the longitudinal and shear acoustic velocities of PBX 9502 as a function of density for die-pressed samples over the range 1.795 g/cc to 1.888 g/cc. The density dependence of the velocities is linear. Thermal cycling of PBX 9502 is known to induce irreversible volume growth. We have measured this volume growth dependence on density for a subset of the pressed parts and find that the most growth occurs for the samples with lowest initial density. The acoustic velocity changes due to the volume growth are significant and reflect damage in the samples.

  19. Generalization and extension of the law of acoustic energy conservation in a nonuniform flow

    NASA Technical Reports Server (NTRS)

    Myers, M. K.

    1986-01-01

    An exact conservation equation is derived which generalizes the familiar acoustic energy equations. The new relation is valid for arbitrary disturbances to a viscous, compressible flow. It is suggested by a development of the acoustic energy equation by means of a regular perturbation expansion of the general energy equation of fluid mechanics. A perturbation energy density and flux are defined and identified as the exact physical quantities whose leading order perturbation representations are the usual acoustic energy density and flux. The conservation equation governing the perturbation energy quantities is shown to yield previously known results for several special cases.

  20. DECAF - Density Estimation for Cetaceans from Passive Acoustic Fixed Sensors

    DTIC Science & Technology

    2010-01-01

    DECAF – Density Estimation for Cetaceans from passive Acoustic Fixed sensors Len Thomas CREEM, University of St Andrews, St Andrews, Fife, Scotland...REPORT DATE 2010 2. REPORT TYPE 3. DATES COVERED 00-00-2010 to 00-00-2010 4. TITLE AND SUBTITLE DECAF - Density Estimation for Cetaceans from...Prescribed by ANSI Std Z39-18 LONG-TERM GOALS Determining the spatial density and distribution of cetacean (whale and dolphin) species is fundamental to

  1. Measured acoustic properties of variable and low density bulk absorbers

    NASA Technical Reports Server (NTRS)

    Dahl, M. D.; Rice, E. J.

    1985-01-01

    Experimental data were taken to determine the acoustic absorbing properties of uniform low density and layered variable density samples using a bulk absober with a perforated plate facing to hold the material in place. In the layered variable density case, the bulk absorber was packed such that the lowest density layer began at the surface of the sample and progressed to higher density layers deeper inside. The samples were placed in a rectangular duct and measurements were taken using the two microphone method. The data were used to calculate specific acoustic impedances and normal incidence absorption coefficients. Results showed that for uniform density samples the absorption coefficient at low frequencies decreased with increasing density and resonances occurred in the absorption coefficient curve at lower densities. These results were confirmed by a model for uniform density bulk absorbers. Results from layered variable density samples showed that low frequency absorption was the highest when the lowest density possible was packed in the first layer near the exposed surface. The layers of increasing density within the sample had the effect of damping the resonances.

  2. 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.

  3. Acoustic Energy Estimates in Inhomogeneous Moving Media

    NASA Technical Reports Server (NTRS)

    Farassat, F.; Farris, Mark

    1999-01-01

    In ducted fan engine noise research, there is a need for defining a simple and easy to use acoustic energy conservation law to help in quantification of noise control techniques. There is a well known conservation law relating acoustic energy and acoustic energy flux in the case of an isentropic irrotational flow. Several different approaches have been taken to generalize this conservation law. For example, Morfey finds an identity by separating out the irrotational part of the perturbed flow. Myers is able to find a series of indentities by observing an algebraic relationship between the basic conservation of energy equation for a background flow and the underlying equations of motion. In an approximate sense, this algebraic relationship is preserved under perturbation. A third approach which seems to have not been pursued in the literature is a result known as Noether's theorem. There is a Lagrangian formulation for the Euler equation of fluid mechanics. Noether's theorem says that any group action that leaves the Lagrangian action invariant leads to a conserved quantity. This presentation will include a survey of current results regarding acoustic energy and preliminary results on the symmetries of the Lagrangian.

  4. Zebra mussel control using acoustic energy

    SciTech Connect

    Tiller, G.W.; Gaucher, T.A.; Menezes, J.K.; Dolat, S.W. )

    1992-01-01

    A practical and economical device or method that reduces zebra mussel colonization without detrimental side effects is highly desirable. An ideal method is one that could be installed near, on, or in existing raw water intakes and conduits. It must have a known effect that is limited to a defined area, should have maximum effects on a targeted species, and preferably have a low life cycle cost than the current alternative methods of control and maintenance. Underwater sound could be such a desirable solution, if found to be an effective control measure for zebra mussels. Although sound most often applies specifically to acoustic energy that is audible to humans, 20 Hertz (Hz) to 20 kiloHertz (kHz), in this report we will use the terms sound and acoustic to include acoustic energy between 100 Hz and 100 MegaHertz (MHz). This research on zebra mussel biofouling is designed to effect the early developmental stages in the life cycle of Dreissena polymorpha (Pallas). Vulnerable stages in the development of D. polymorpha that might yield to site-specific acoustic deterrence measures include the free-swimming larval veliger stage, the postveliger pre-attachment demersal stage, and the immediate post-attachment stage. The proposed applications include surface treatment to prevent, reduce or eliminate colonization on underwater structures, and the stream treatment to reduce or eliminate (destroy) mussel larvae entrained in a moving volume of water.

  5. Diffusive Propagation of Energy in a Non-acoustic Chain

    NASA Astrophysics Data System (ADS)

    Komorowski, Tomasz; Olla, Stefano

    2017-01-01

    We consider a non-acoustic chain of harmonic oscillators with the dynamics perturbed by a random local exchange of momentum, such that energy and momentum are conserved. The macroscopic limits of the energy density, momentum and the curvature (or bending) of the chain satisfy a system of evolution equations. We prove that, in a diffusive space-time scaling, the curvature and momentum evolve following a linear system that corresponds to a damped E uler-B ernoulli beam equation. The macroscopic energy density evolves following a non linear diffusive equation. In particular, the energy transfer is diffusive in this dynamics. This provides a first rigorous example of a normal diffusion of energy in a one dimensional dynamics that conserves the momentum.

  6. Origin of negative density and modulus in acoustic metamaterials

    NASA Astrophysics Data System (ADS)

    Lee, Sam H.; Wright, Oliver B.

    2016-01-01

    This paper provides a review and fundamental physical interpretation for the effective densities and moduli of acoustic metamaterials. We introduce the terminology of hidden force and hidden source of volume: the effective density or modulus is negative when the hidden force or source of volume is larger than, and operates in antiphase to, respectively, the force or volume change that would be obtained in their absence. We demonstrate this ansatz for some established acoustic metamaterials with elements based on membranes, Helmholtz resonators, springs, and masses. The hidden force for membrane-based acoustic metamaterials, for instance, is the force from the membrane tension. The hidden source for a Helmholtz-resonator-based metamaterial is the extra air volume injected from the resonator cavity. We also explain the analogous concepts for pure mass-and-spring systems, in which case, hidden forces can arise from masses and springs fixed inside other masses, whereas hidden sources—more aptly termed hidden expanders of displacement in this case—can arise from light rigid trusses coupled to extra degrees of freedom for mechanical motion such as the case of coupling to masses that move at right angles to the wave-propagation direction. This overall picture provides a powerful tool for conceptual understanding and design of new acoustic metamaterials, and avoids common pitfalls involved in determining the effective parameters of such materials.

  7. Density can be misleading for low-density species: benefits of passive acoustic monitoring.

    PubMed

    Rogers, Tracey L; Ciaglia, Michaela B; Klinck, Holger; Southwell, Colin

    2013-01-01

    Climate-induced changes may be more substantial within the marine environment, where following ecological change is logistically difficult, and typically expensive. As marine animals tend to produce stereotyped, long-range signals, they are ideal for repeatable surveying. In this study we illustrate the potential for calling rates to be used as a tool for determining habitat quality by using an Antarctic pack-ice seal, the leopard seal, as a model.With an understanding of the vocal behavior of a species, their seasonal and diurnal patterns, sex and age-related differences, an underwater passive-acoustic survey conducted alongside a visual survey in an arc of 4,225 km across the Davis Sea, Eastern Antarctica, showed that while acoustic and visual surveys identified similar regions as having high densities, the acoustic surveys surprisingly identified the opposite regions as being 'critical' habitats. Density surveys of species that cannot be differentiated into population classes may be misleading because overall density can be a negative indicator of habitat quality.Under special circumstances acoustics can offer enormous advantage over traditional techniques and open up monitoring to regions that are remote, difficult and expensive to work within, no longer restricting long-term community assessment to resource-wealthy communities. As climatic change affects a broad range of organisms across geographic boundaries we propose that capitalizing on the significant advances in passive acoustic technology, alongside physical acoustics and population modeling, can help in addressing ecological questions more broadly.

  8. 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.

  9. Method of measuring reactive acoustic power density in a fluid

    DOEpatents

    Wheatley, J.C.; Swift, G.W.; Migliori, A.

    1985-09-03

    A method for determining reactive acoustic power density level and its direction in a fluid using a single sensor is disclosed. In the preferred embodiment, an apparatus for conducting the method, which is termed a thermoacoustic couple, consists of a stack of thin, spaced apart polymeric plates, selected ones of which include multiple bimetallic thermocouple junctions positioned along opposite end edges thereof. The thermocouple junctions are connected in series in the nature of a thermopile, and are arranged so as to be responsive to small temperature differences between the opposite edges of the plates. The magnitude of the temperature difference, as represented by the magnitude of the electrical potential difference generated by the thermopile, is found to be directly related to the level of acoustic power density in the gas. 5 figs.

  10. Method of measuring reactive acoustic power density in a fluid

    DOEpatents

    Wheatley, John C.; Swift, Gregory W.; Migliori, Albert

    1985-01-01

    A method for determining reactive acoustic power density level and its direction in a fluid using a single sensor is disclosed. In the preferred embodiment, an apparatus for conducting the method, which is termed a thermoacoustic couple, consists of a stack of thin, spaced apart polymeric plates, selected ones of which include multiple bimetallic thermocouple junctions positioned along opposite end edges thereof. The thermocouple junctions are connected in series in the nature of a thermopile, and are arranged so as to be responsive to small temperature differences between the opposite edges of the plates. The magnitude of the temperature difference, as represented by the magnitude of the electrical potential difference generated by the thermopile, is found to be directly related to the level of acoustic power density in the gas.

  11. Ultrasound acoustic wave energy transfer and harvesting

    NASA Astrophysics Data System (ADS)

    Shahab, Shima; Leadenham, Stephen; Guillot, François; Sabra, Karim; Erturk, Alper

    2014-04-01

    This paper investigates low-power electricity generation from ultrasound acoustic wave energy transfer combined with piezoelectric energy harvesting for wireless applications ranging from medical implants to naval sensor systems. The focus is placed on an underwater system that consists of a pulsating source for spherical wave generation and a harvester connected to an external resistive load for quantifying the electrical power output. An analytical electro-acoustic model is developed to relate the source strength to the electrical power output of the harvester located at a specific distance from the source. The model couples the energy harvester dynamics (piezoelectric device and electrical load) with the source strength through the acoustic-structure interaction at the harvester-fluid interface. Case studies are given for a detailed understanding of the coupled system dynamics under various conditions. Specifically the relationship between the electrical power output and system parameters, such as the distance of the harvester from the source, dimensions of the harvester, level of source strength, and electrical load resistance are explored. Sensitivity of the electrical power output to the excitation frequency in the neighborhood of the harvester's underwater resonance frequency is also reported.

  12. Composite acoustic medium with simultaneously negative density and modulus.

    PubMed

    Lee, Sam Hyeon; Park, Choon Mahn; Seo, Yong Mun; Wang, Zhi Guo; Kim, Chul Koo

    2010-02-05

    We fabricated an acoustic composite structure consisting of a periodic array of interspaced membranes and side holes. Experimental data on the transmission, effective density, and phase velocity are presented. The system exhibits two critical frequencies, omega{SH} and omega{c}. Our metamaterial is double negative and transparent for frequencies lower than omega{SH}. For the frequencies omega{SH}density is negative. For the frequencies above omega{c}, the system is double positive and transparent. The present medium exhibits a very wide double negative spectral range that opens the possibility of the application of metamaterials for "white lights."

  13. Acoustic methods to monitor sliver linear density and yarn strength

    DOEpatents

    Sheen, Shuh-Haw; Chien, Hual-Te; Raptis, Apostolos C.

    1997-01-01

    Methods and apparatus are provided for monitoring sliver and yarn characteristics. Transverse waves are generated relative to the sliver or yarn. At least one acoustic sensor is in contact with the sliver or yarn for detecting waves coupled to the sliver or yarn and for generating a signal. The generated signal is processed to identify the predefined characteristics including sliver or yarn linear density. The transverse waves can be generated with a high-powered acoustic transmitter spaced relative to the sliver or yarn with large amplitude pulses having a central frequency in a range between 20 KHz and 40 KHz applied to the transmitter. The transverse waves can be generated by mechanically agitating the sliver or yarn with a tapping member.

  14. States of high energy density

    SciTech Connect

    Murray, M.

    1988-02-01

    The transverse energy, E/sub tau/ spectra for O/sup 16/ and S/sup 32/ incident for various elements at 200 GeVnucleon are shown. The target and projectile dependencies of the data are discussed. The energy density achieved is estimated. For O/sup 16/ on Tungsten the multiplicity spectrum is also presented as well as the pseudorapidity spectra as a function of the transverse energy. The multiplicity cross section dsigmadN as measured in the backward hemisphere (0.9 < /eta/ < 2.9/ is found to be very similar in shape to the transverse energy distribution dsigmadE/tau/ reflecting the particular geometry of nucleus nucleus nucleus collisions. The dependence on the atomic mass of the target, A/sub tau/ and projectile A/sub p/ is not what one would expect from naive considerations.

  15. Canonical Acoustics and Its Application to Surface Acoustic Wave on Acoustic Metamaterials

    NASA Astrophysics Data System (ADS)

    Shen, Jian Qi

    2016-08-01

    In a conventional formalism of acoustics, acoustic pressure p and velocity field u are used for characterizing acoustic waves propagating inside elastic/acoustic materials. We shall treat some fundamental problems relevant to acoustic wave propagation alternatively by using canonical acoustics (a more concise and compact formalism of acoustic dynamics), in which an acoustic scalar potential and an acoustic vector potential (Φ ,V), instead of the conventional acoustic field quantities such as acoustic pressure and velocity field (p,u) for characterizing acoustic waves, have been defined as the fundamental variables. The canonical formalism of the acoustic energy-momentum tensor is derived in terms of the acoustic potentials. Both the acoustic Hamiltonian density and the acoustic Lagrangian density have been defined, and based on this formulation, the acoustic wave quantization in a fluid is also developed. Such a formalism of acoustic potentials is employed to the problem of negative-mass-density assisted surface acoustic wave that is a highly localized surface bound state (an eigenstate of the acoustic wave equations). Since such a surface acoustic wave can be strongly confined to an interface between an acoustic metamaterial (e.g., fluid-solid composite structures with a negative dynamical mass density) and an ordinary material (with a positive mass density), it will give rise to an effect of acoustic field enhancement on the acoustic interface, and would have potential applications in acoustic device design for acoustic wave control.

  16. High energy density aluminum battery

    SciTech Connect

    Brown, Gilbert M.; Paranthaman, Mariappan Parans; Dai, Sheng; Dudney, Nancy J.; Manthiram, Arumugan; McIntyre, Timothy J.; Sun, Xiao-Guang; Liu, Hansan

    2016-10-11

    Compositions and methods of making are provided for a high energy density aluminum battery. The battery comprises an anode comprising aluminum metal. The battery further comprises a cathode comprising a material capable of intercalating aluminum or lithium ions during a discharge cycle and deintercalating the aluminum or lithium ions during a charge cycle. The battery further comprises an electrolyte capable of supporting reversible deposition and stripping of aluminum at the anode, and reversible intercalation and deintercalation of aluminum or lithium at the cathode.

  17. Acoustic metamaterial with negative mass density in water

    SciTech Connect

    Chen, Huaijun; Zhai, Shilong; Ding, Changlin; Luo, Chunrong; Zhao, Xiaopeng

    2015-09-07

    A two-dimensional (2D) acoustic metamaterial (AM) with negative effective mass density in water is designed by periodically arranging hollow tube “meta-atoms.” Experimental and simulated results demonstrate that transmission dips accompanied with inverse phases are presented in the transmission spectra of the 2D AM at the ultrasonic frequency band. Effective parameters extracted from the experimental measured transmission and reflection coefficients of the 2D AM show that the effective mass density and refractive index are negative near the dip frequency range of 35.31–35.94 kHz. The simulation also shows the negative response in the 2D AM. Due to the excellent properties, the 2D AM is appealing for the potential applications in areas such as subwavelength imaging, ultrasonic cloaking in water, and so on.

  18. Energy Efficient Engine acoustic supporting technology report

    NASA Technical Reports Server (NTRS)

    Lavin, S. P.; Ho, P. Y.

    1985-01-01

    The acoustic development of the Energy Efficient Engine combined testing and analysis using scale model rigs and an integrated Core/Low Spool demonstration engine. The scale model tests show that a cut-on blade/vane ratio fan with a large spacing (S/C = 2.3) is as quiet as a cut-off blade/vane ratio with a tighter spacing (S/C = 1.27). Scale model mixer tests show that separate flow nozzles are the noisiest, conic nozzles the quietest, with forced mixers in between. Based on projections of ICLS data the Energy Efficient Engine (E3) has FAR 36 margins of 3.7 EPNdB at approach, 4.5 EPNdB at full power takeoff, and 7.2 EPNdB at sideline conditions.

  19. 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

  20. 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.

  1. Note: Vibration energy harvesting based on a round acoustic fence

    NASA Astrophysics Data System (ADS)

    Cui, Xiao-bin; Huang, Cheng-ping; Hu, Jun-hui

    2015-07-01

    An energy harvester based on a round acoustic fence (RAF) has been proposed and studied. The RAF is composed of cylindrical stubs stuck in a circular array on a thin metal plate, which can confine the acoustic energy efficiently. By removing one stub and thus opening a small gap in the RAF, acoustic leakage with larger intensity can be produced at the gap opening. With the vibration source surrounded by the RAF, the energy harvesting at the gap opening has a wide bandwidth and is insensitive to the position of the vibration source. The results may have potential applications in harvesting the energy of various vibration sources in solid structure.

  2. Workshop on the Detection, Classification, Localization and Density Estimation of Marine Mammals Using Passive Acoustics - 2015

    DTIC Science & Technology

    2015-09-30

    and Density Estimation of Marine Mammals Using Passive Acoustics - 2015 John A. Hildebrand Scripps Institution of Oceanography UCSD La Jolla...classification, localization and density estimation of marine mammals using passive acoustics , and by doing so advance the state of the art in this field...Passive Acoustics was organized and held at the Scripps Institution of Oceanography (SIO) in July 2015. The objective of ONR support for the

  3. Probability distribution of the vacuum energy density

    SciTech Connect

    Duplancic, Goran; Stefancic, Hrvoje; Glavan, Drazen

    2010-12-15

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

  4. Cheap DECAF: Density Estimation for Cetaceans from Acoustic Fixed Sensors Using Separate, Non-Linked Devices

    DTIC Science & Technology

    2011-09-30

    whale (Balaenoptera physalus) from a sparse array of ocean bottom seismometers (OBSs) will be the dataset used to develop and test a variety of density...T. Marques. 2009. Taming the Jez monster : Estimating fin whale spatial density using acoustic propagation modeling. J. Acoust. Soc. Am. 126(4):2229

  5. The Quantum Energy Density: Improved E

    SciTech Connect

    Krogel, Jaron; Yu, Min; Kim, Jeongnim; Ceperley, David M.

    2013-01-01

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

  6. 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.

  7. Acoustic energy-driven fluid pump and method

    SciTech Connect

    Janus, Michael C.; Richards, George A.; Robey, Edward H.

    1997-12-01

    Bulk fluid motion is promoted in a gaseous fluid contained within a conduit system provided with a diffuser without the need for a mean pressure differential across the conduit system. The contacting of the gaseous fluid with unsteady energy at a selected frequency and pressure amplitude induces fluid flow through the conical diffuser. The unsteady energy can be provided by pulse combustors, thermoacoustic engines, or acoustic energy generators such as acoustic speakers.

  8. An Energy Harvesting Underwater Acoustic Transmitter for Aquatic Animals

    SciTech Connect

    Li, Huidong; Tian, Chuan; Lu, Jun; Myjak, Mitchell J.; Martinez, Jayson J.; Brown, Richard S.; Deng, Zhiqun Daniel

    2016-09-20

    This paper presents a self-powered underwater acoustic transmitter using a piezoelectric beam to harvest the mechanical energy from fish swimming. This transmitter does not require a battery and is demonstrated in live fish. It transmits an acoustic waveform as the implanted fish swims. It enables long-term monitoring of aquatic animals.

  9. Holographic Dark Energy Density and JBP Parametrization

    NASA Astrophysics Data System (ADS)

    Saadat, Hassan; Mousavi, S. N.; Saadat, A. M.

    2011-09-01

    In this article we consider the holographic dark energy density. We study dark energy density in Universe with arbitrary spatially curvature described by the Friedmann-Robertson-Walker metric. We use Jassal-Bagla-Padmanabhan parametrization to specify dark energy density.

  10. Enhanced vibration based energy harvesting using embedded acoustic black holes

    NASA Astrophysics Data System (ADS)

    Zhao, L.; Semperlotti, F.; Conlon, S. C.

    2014-03-01

    In this paper, we investigate the use of dynamic structural tailoring via the concept of an Acoustic Black Hole (ABH) to enhance the performance of piezoelectric based energy harvesting from operational mechanical vibrations. The ABH is a variable thickness structural feature that can be embedded in the host structure allowing a smooth reduction of the phase velocity while minimizing the amplitude of reflected waves. The ABH thickness variation is typically designed according to power-law profiles. As a propagating wave enters the ABH, it is progressively slowed down while its wavelength is compressed. This effect results in structural areas with high energy density that can be exploited effectively for energy harvesting. The potential of ABH for energy harvesting is shown via a numerical study based on fully coupled finite element electromechanical models of an ABH tapered plate with surface mounted piezo-transducers. The performances of the novel design are evaluated by direct comparison with a non-tapered structure in terms of energy ratios and attenuation indices. Results show that the tailored structural design allows a drastic increase in the harvested energy both for steady state and transient excitation. Performance dependencies of key design parameters are also investigated.

  11. Origami acoustics: using principles of folding structural acoustics for simple and large focusing of sound energy

    NASA Astrophysics Data System (ADS)

    Harne, Ryan L.; Lynd, Danielle T.

    2016-08-01

    Fixed in spatial distribution, arrays of planar, electromechanical acoustic transducers cannot adapt their wave energy focusing abilities unless each transducer is externally controlled, creating challenges for the implementation and portability of such beamforming systems. Recently, planar, origami-based structural tessellations are found to facilitate great versatility in system function and properties through kinematic folding. In this research we bridge the physics of acoustics and origami-based design to discover that the simple topological reconfigurations of a Miura-ori-based acoustic array yield many orders of magnitude worth of reversible change in wave energy focusing: a potential for acoustic field morphing easily obtained through deployable, tessellated architectures. Our experimental and theoretical studies directly translate the roles of folding the tessellated array to the adaptations in spectral and spatial wave propagation sensitivities for far field energy transmission. It is shown that kinematic folding rules and flat-foldable tessellated arrays collectively provide novel solutions to the long-standing challenges of conventional, electronically-steered acoustic beamformers. While our examples consider sound radiation from the foldable array in air, linear acoustic reciprocity dictates that the findings may inspire new innovations for acoustic receivers, e.g. adaptive sound absorbers and microphone arrays, as well as concepts that include water-borne waves.

  12. Converting acoustic energy into useful other energy forms

    DOEpatents

    Putterman, Seth J.; Barber, Bradley Paul; Hiller, Robert Anthony; Lofstedt, Ritva Maire Johanna

    1997-01-01

    Sonoluminescence is an off-equilibrium phenomenon in which the energy of a resonant sound wave in a liquid is highly concentrated so as to generate flashes of light. The conversion of sound to light represents an energy amplification of eleven orders of magnitude. The flashes which occur once per cycle of the audible or ultrasonic sound fields can be comprised of over one million photons and last for less 100 picoseconds. The emission displays a clocklike synchronicity; the jitter in time between consecutive flashes is less than fifty picoseconds. The emission is blue to the eye and has a broadband spectrum increasing from 700 nanometers to 200 nanometers. The peak power is about 100 milliWatts. The initial stage of the energy focusing is effected by the nonlinear oscillations of a gas bubble trapped in the liquid. For sufficiently high drive pressures an imploding shock wave is launched into the gas by the collapsing bubble. The reflection of the shock from its focal point results in high temperatures and pressures. The sonoluminescence light emission can be sustained by sensing a characteristic of the emission and feeding back changes into the driving mechanism. The liquid is in a sealed container and the seeding of the gas bubble is effected by locally heating the liquid after sealing the container. Different energy forms than light can be obtained from the converted acoustic energy. When the gas contains deuterium and tritium there is the feasibility of the other energy form being fusion, namely including the generation of neutrons.

  13. Density dependence of nuclear symmetry energy

    NASA Astrophysics Data System (ADS)

    Behera, B.; Routray, T. R.; Tripathy, S. K.

    2016-10-01

    High density behavior of nuclear symmetry energy is studied on the basis of the stiffest density dependence of asymmetric contribution to energy per nucleon in charge neutral n + p + e + μ matter under beta equilibrium. The density dependence of nuclear symmetry energy obtained in this way is neither very stiff nor soft at high densities and is found to be in conformity with recent observations of neutron stars.

  14. Fracture energy analysis via acoustic emission

    NASA Astrophysics Data System (ADS)

    Maslov, I. I.; Gradov, O. M.

    1986-04-01

    The results of previous studies on acoustic emission during fatigue loading are used to relate the characteristics of the acoustic signals to the fracture processes occurring at the crack tip. At stresses below the yield point of the material, discrete acoustic emissions are produced, their amplitude distribution being described by a monotonically decreasing function. At stresses near the yield point, the signals are continuous with a peak observed in the amplitude distribution function, while above the yield point the acoustic emission resumes the character it had below the yield point. It is shown that these emissions correspond to the formation of individual microfractures, to the process of macroplastic deformation and to stepwise crack propagation of the structurally disordered material, respectively.

  15. Acoustic energy transmission in cast iron pipelines

    NASA Astrophysics Data System (ADS)

    Kiziroglou, Michail E.; Boyle, David E.; Wright, Steven W.; Yeatman, Eric M.

    2015-12-01

    In this paper we propose acoustic power transfer as a method for the remote powering of pipeline sensor nodes. A theoretical framework of acoustic power propagation in the ceramic transducers and the metal structures is drawn, based on the Mason equivalent circuit. The effect of mounting on the electrical response of piezoelectric transducers is studied experimentally. Using two identical transducer structures, power transmission of 0.33 mW through a 1 m long, 118 mm diameter cast iron pipe, with 8 mm wall thickness is demonstrated, at 1 V received voltage amplitude. A near-linear relationship between input and output voltage is observed. These results show that it is possible to deliver significant power to sensor nodes through acoustic waves in solid structures. The proposed method may enable the implementation of acoustic - powered wireless sensor nodes for structural and operation monitoring of pipeline infrastructure.

  16. Using Streamlines to Visualize Acoustic Energy Flow Across Boundaries

    DTIC Science & Technology

    2008-07-01

    radiate from a point source in a homogeneous fluid and propagate across a plane boundary into a dissimilar homogeneous fluid, the acoustic field may...associated with diffraction i.e., those components that vanish with increasing frequency. The energy flow from a continuous-wave monopole point source...vector, averaged over a wave cycle. It is seen that the acoustic energy flow is not always in line with the “Snell’s law” or stationary phase path. Also

  17. Shear-horizontal surface acoustic wave phononic device with high density filling material for ultra-low power sensing applications

    SciTech Connect

    Richardson, M.; Bhethanabotla, V. R.; Sankaranarayanan, S. K. R. S.

    2014-06-23

    Finite element simulations of a phononic shear-horizontal surface acoustic wave (SAW) sensor based on ST 90°-X Quartz reveal a dramatic reduction in power consumption. The phononic sensor is realized by artificially structuring the delay path to form an acoustic meta-material comprised of a periodic microcavity array incorporating high-density materials such as tantalum or tungsten. Constructive interference of the scattered and secondary reflected waves at every microcavity interface leads to acoustic energy confinement in the high-density regions translating into reduced power loss. Tantalum filled cavities show the best performance while tungsten inclusions create a phononic bandgap. Based on our simulation results, SAW devices with tantalum filled microcavities were fabricated and shown to significantly decrease insertion loss. Our findings offer encouraging prospects for designing low power, highly sensitive portable biosensors.

  18. Nonlinear effects in an acoustic metamaterial with simultaneous negative modulus and density

    NASA Astrophysics Data System (ADS)

    Li, Yifeng; Lan, Jun; Li, Baoshun; Liu, Xiaozhou; Zhang, Jiashu

    2016-10-01

    Nonlinear effects in an acoustic metamaterial with simultaneous negative modulus and density based on Helmholtz resonators and membranes periodically distributed along a pipe are studied theoretically. Analyses of the transmission coefficient and dispersion relation of the composite system are realized using the acoustic transmission line method and Bloch theory, respectively. Due to the nonlinearities of the Helmholtz resonators and membranes, the acoustic wave propagation properties vary with the different incident acoustic intensities, and the frequency band gaps of the transmission coefficient are amplitude dependent. The nonlinearities shift the double negative pass band into the adjacent modulus negative forbidden band and transform the metamaterial from an acoustic insulator into an acoustic conductor, leading to some new potential acoustic applications.

  19. Reverberant acoustic energy in auditoria that comprise systems of coupled rooms

    NASA Astrophysics Data System (ADS)

    Summers, Jason E.

    2003-11-01

    A frequency-dependent model for reverberant energy in coupled rooms is developed and compared with measurements for a 1:10 scale model and for Bass Hall, Ft. Worth, TX. At high frequencies, prior statistical-acoustics models are improved by geometrical-acoustics corrections for decay within sub-rooms and for energy transfer between sub-rooms. Comparisons of computational geometrical acoustics predictions based on beam-axis tracing with scale model measurements indicate errors resulting from tail-correction assuming constant quadratic growth of reflection density. Using ray tracing in the late part corrects this error. For mid-frequencies, the models are modified to account for wave effects at coupling apertures by including power transmission coefficients. Similarly, statical-acoustics models are improved through more accurate estimates of power transmission measurements. Scale model measurements are in accord with the predicted behavior. The edge-diffraction model is adapted to study transmission through apertures. Multiple-order scattering is theoretically and experimentally shown inaccurate due to neglect of slope diffraction. At low frequencies, perturbation models qualitatively explain scale model measurements. Measurements confirm relation of coupling strength to unperturbed pressure distribution on coupling surfaces. Measurements in Bass Hall exhibit effects of the coupled stage house. High frequency predictions of statistical acoustics and geometrical acoustics models and predictions of coupling apertures all agree with measurements.

  20. Density and Shape Effects in the Acoustic Propulsion of Bimetallic Nanorod Motors.

    PubMed

    Ahmed, Suzanne; Wang, Wei; Bai, Lanjun; Gentekos, Dillon T; Hoyos, Mauricio; Mallouk, Thomas E

    2016-04-26

    Bimetallic nanorods are propelled without chemical fuels in megahertz (MHz) acoustic fields, and exhibit similar behaviors to single-metal rods, including autonomous axial propulsion and organization into spinning chains. Shape asymmetry determines the direction of axial movement of bimetallic rods when there is a small difference in density between the two metals. Movement toward the concave end of these rods is inconsistent with a scattering mechanism that we proposed earlier for acoustic propulsion, but is consistent with an acoustic streaming model developed more recently by Nadal and Lauga ( Phys. Fluids 2014 , 26 , 082001 ). Longer rods were slower at constant power, and their speed was proportional to the square of the power density, in agreement with the acoustic streaming model. The streaming model was further supported by a correlation between the disassembly of spinning chains of rods and a sharp decrease in the axial speed of autonomously moving motors within the levitation plane of the cylindrical acoustic cell. However, with bimetallic rods containing metals of different densities, a consistent polarity of motion was observed with the lighter metal end leading. Speed comparisons between single-metal rods of different densities showed that those of lower density are propelled faster. So far, these density effects are not explained in the streaming model. The directionality of bimetallic rods in acoustic fields is intriguing and offers some new possibilities for designing motors in which shape, material, and chemical asymmetry might be combined for enhanced functionality.

  1. Hybrid acoustic energy harvesting using combined electromagnetic and piezoelectric conversion

    NASA Astrophysics Data System (ADS)

    Khan, Farid Ullah; Izhar

    2016-02-01

    This paper reports a novel hybrid acoustic energy harvester. The harvester utilizes both the electromagnetic and piezoelectric conversion mechanisms simultaneously to convert the ambient acoustical noise into electrical power for self-powered wireless sensor nodes. The proposed harvester is comprised of a Helmholtz resonator, two magnets mounted on a piezoelectric plate, and a wound coil located under the magnets. The harvester is characterized both under harmonic and real random acoustical excitations. In-lab, under harmonic acoustical excitation at a sound pressure level of 130 dB and frequency of 2.1 kHz, an optimum power of 2.86 μW (at 114 Ω optimum load) is obtained from electromagnetic conversion and 50 μW (at 1000 Ω optimum load) is generated by the piezoelectric harvester's part. Moreover, in real acoustical environment of a domestic electric generator the peak voltages of 40 and 123 mV are produced by the electromagnetic and piezoelectric portions of the acoustic energy harvester.

  2. Rock softening due to ultrasonic acoustical energy

    NASA Astrophysics Data System (ADS)

    Freund, F. T.; Freund, M. M.; Hedberg, C. M.; Haller, K. C.; Dahlgren, R.; Williams, C.; Agrawal, P.

    2011-12-01

    When igneous or high-grade metamorphic rocks are subjected to deviatoric stresses, dormant defects existing in the matrix of common rock-forming minerals become activated releasing mobile positive hole charge carriers. These defects consist of pairs of oxygen anions in the 1- valence state, e.g. peroxy links such as O3Si-OO-SiO3. When the peroxy bond breaks, O3Si-O:O-SiO3, an electron is transferred from a neighboring O2- creating a trapped electron defect, O3Si-O.O-SiO3, while the donor oxygen, now O-, turns into a defect electron or hole that can propagate as a highly mobile positive charge traveling along the upper edge of the valence band. There is evidence that the wave function associated with these positive hole charge carriers is highly delocalized. The delocalization lowers the electron density at the surrounding O2-, hence the bond energy, thereby affecting fundamental properties including the mechanical strength. To demonstrate the rock softening effect we mounted a rectangular bar of fine-grained gabbro about 30 cm long in a horizontal position clamping it at one end. A piezoelectric transducer (PZT) was epoxied to the fixed end of the rock bar to send ultrasonic energy at 57 KHz toward the cantilevered end. The downward deflection of the free end of the beam was measured with an interferometer to a high degree of precision. With ultrasonic energy present, the free end of the beam sagged near-instantaneously by about 0.2 μm and continued to sag slowly by about 0.4 μm over 120 sec. Upon turning off the PZT the rock bar returned slowly to the baseline deflection value. The ultrasound waves generated by the PZT activate positive holes, changing the apparent stiffness of the beam and causing its cantilevered end to bend downward. We also conducted experiments using an Instron 5569 Dual Column Testing System to subject rectangular plates (15.2 x 3.8 x 0.5 cm) of the same gabbro to dynamic three-point flexural tests. Using electrostatic fields of different

  3. A Correlated Study of the Response of a Satellite to Acoustic Radiation Using Statistical Energy Analysis and Acoustic Test Data

    SciTech Connect

    CAP,JEROME S.; TRACEY,BRIAN

    1999-11-15

    Aerospace payloads, such as satellites, are subjected to vibroacoustic excitation during launch. Sandia's MTI satellite has recently been certified to this environment using a combination of base input random vibration and reverberant acoustic noise. The initial choices for the acoustic and random vibration test specifications were obtained from the launch vehicle Interface Control Document (ICD). In order to tailor the random vibration levels for the laboratory certification testing, it was necessary to determine whether vibration energy was flowing across the launch vehicle interface from the satellite to the launch vehicle or the other direction. For frequencies below 120 Hz this issue was addressed using response limiting techniques based on results from the Coupled Loads Analysis (CLA). However, since the CLA Finite Element Analysis FEA model was only correlated for frequencies below 120 Hz, Statistical Energy Analysis (SEA) was considered to be a better choice for predicting the direction of the energy flow for frequencies above 120 Hz. The existing SEA model of the launch vehicle had been developed using the VibroAcoustic Payload Environment Prediction System (VAPEPS) computer code [1]. Therefore, the satellite would have to be modeled using VAPEPS as well. As is the case for any computational model, the confidence in its predictive capability increases if one can correlate a sample prediction against experimental data. Fortunately, Sandia had the ideal data set for correlating an SEA model of the MTI satellite--the measured response of a realistic assembly to a reverberant acoustic test that was performed during MTI's qualification test series. The first part of this paper will briefly describe the VAPEPS modeling effort and present the results of the correlation study for the VAPEPS model. The second part of this paper will present the results from a study that used a commercial SEA software package [2] to study the effects of in-plane modes and to

  4. Modeling High Energy Density Plasmas

    NASA Astrophysics Data System (ADS)

    Albritton, J. R.; Liberman, D. A.; Wilson, B. G.

    1999-11-01

    Ultra-short-pulse lasers are being used to form plasmas at near normal/solid density, heating a target in a time shorter than that on which it can expand. Radiative signatures of the dense plasma conditions are a key diagnostic, and typically require the support of modeling for their design and interpretation. Modeling also often serves to guide the experimental program of work. Here we report on our first attempts to use the INFERNO average-atom atomic model to a construct detailed-configuration-accounting description of the plasma equation-of-state, that is, its distribution of ionization and excitation states, and further, its radiative line, edge, and continuum features.

  5. Density Scaling of Noninteracting Kinetic Energy Functionals.

    PubMed

    Borgoo, Alex; Tozer, David J

    2013-05-14

    The influence of imposing an approximate density scaling condition on a noninteracting kinetic energy functional is investigated. A simple generalized gradient approximation (GGA) is presented, which satisfies both the density scaling condition and the usual coordinate scaling condition; the remaining multiplicative constant is determined from an energy criterion. In post-Kohn-Sham calculations, noninteracting kinetic energies of the closed-shell molecules of the G1 set determined using the GGA are a modest improvement over those determined using the corresponding local functional, which does not satisfy the density scaling condition. Potential energy curves of CO, F2, and P2 exhibit binding with the GGA, compared to purely repulsive curves with the local functional. Adjusting the exponent in the GGA form in order to optimize energy accuracy violates the density scaling condition, and two of the diatomics no longer exhibit binding. Results are compared with those from other local/GGA functionals in the literature.

  6. Thermal Acoustic Sensor for High Pulse Energy X-ray FEL Beams

    SciTech Connect

    Smith, T.J.; Frisch, J.C.; Kraft, E.M.; Loos, J.; Bentsen, G.S.; /Rochester U.

    2011-12-13

    The pulse energy density of X-ray FELs will saturate or destroy conventional X-ray diagnostics, and the use of large beam attenuation will result in a beam that is dominated by harmonics. We present preliminary results at the LCLS from a pulse energy detector based on the thermal acoustic effect. In this type of detector an X-ray resistant material (boron carbide in this system) intercepts the beam. The pulse heating of the target material produces an acoustic pulse that can be detected with high frequency microphones to produce a signal that is linear in the absorbed energy. The thermal acoustic detector is designed to provide first- and second-order calorimetric measurement of X-ray FEL pulse energy. The first-order calorimetry is a direct temperature measurement of a target designed to absorb all or most of the FEL pulse power with minimal heat leak. The second-order measurement detects the vibration caused by the rapid thermoelastic expansion of the target material each time it absorbs a photon pulse. Both the temperature change and the amplitude of the acoustic signal are directly related to the photon pulse energy.

  7. An acoustic bending waveguide designed by anisotropic density-near-zero metamaterial

    NASA Astrophysics Data System (ADS)

    Wang, Yang-Yang; Ding, Er-Liang; Liu, Xiao-Zhou; Gong, Xiu-Fen

    2016-12-01

    Anisotropic metamaterial with only one component of the mass density tensor near zero (ADNZ) is proposed to control the sound wave propagation. We find that such an anisotropic metamaterial can be used to realize perfect bending waveguides. According to a coordinate transformation, the surface waves on the input and output interfaces of the ADNZ metamaterial induces the sound energy flow to be redistributed and match smoothly with the propagating modes inside the metamaterial waveguide. According to the theory of bending waveguide, we realize the “T”-type sound shunting and convergence, as well as acoustic channel selection by embedding small-sized defects. Numerical calculations are performed to confirm the above effects. Project supported by the National Basic Research Program of China (Grant No. 2012CB921504), the National Natural Science Foundation of China (Grant No. 11474160), the Fundamental Research Funds for the Central Universities, China (Grant No. 020414380001), the State Key Laboratory of Acoustics, Chinese Academy of Sciences (Grant No. SKLA201609), and the Priority Academic Program Development of Jiangsu Higher Education Institution, China.

  8. 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.

  9. Baryon acoustic oscillation intensity mapping of dark energy.

    PubMed

    Chang, Tzu-Ching; Pen, Ue-Li; Peterson, Jeffrey B; McDonald, Patrick

    2008-03-07

    The expansion of the Universe appears to be accelerating, and the mysterious antigravity agent of this acceleration has been called "dark energy." To measure the dynamics of dark energy, baryon acoustic oscillations (BAO) can be used. Previous discussions of the BAO dark energy test have focused on direct measurements of redshifts of as many as 10(9) individual galaxies, by observing the 21 cm line or by detecting optical emission. Here we show how the study of acoustic oscillation in the 21 cm brightness can be accomplished by economical three-dimensional intensity mapping. If our estimates gain acceptance they may be the starting point for a new class of dark energy experiments dedicated to large angular scale mapping of the radio sky, shedding light on dark energy.

  10. Baryon Acoustic Oscillation Intensity Mapping of Dark Energy

    NASA Astrophysics Data System (ADS)

    Chang, Tzu-Ching; Pen, Ue-Li; Peterson, Jeffrey B.; McDonald, Patrick

    2008-03-01

    The expansion of the Universe appears to be accelerating, and the mysterious antigravity agent of this acceleration has been called “dark energy.” To measure the dynamics of dark energy, baryon acoustic oscillations (BAO) can be used. Previous discussions of the BAO dark energy test have focused on direct measurements of redshifts of as many as 109 individual galaxies, by observing the 21 cm line or by detecting optical emission. Here we show how the study of acoustic oscillation in the 21 cm brightness can be accomplished by economical three-dimensional intensity mapping. If our estimates gain acceptance they may be the starting point for a new class of dark energy experiments dedicated to large angular scale mapping of the radio sky, shedding light on dark energy.

  11. An Efficient Acoustic Density Estimation Method with Human Detectors Applied to Gibbons in Cambodia

    PubMed Central

    Kidney, Darren; Rawson, Benjamin M.; Borchers, David L.; Stevenson, Ben C.; Marques, Tiago A.; Thomas, Len

    2016-01-01

    Some animal species are hard to see but easy to hear. Standard visual methods for estimating population density for such species are often ineffective or inefficient, but methods based on passive acoustics show more promise. We develop spatially explicit capture-recapture (SECR) methods for territorial vocalising species, in which humans act as an acoustic detector array. We use SECR and estimated bearing data from a single-occasion acoustic survey of a gibbon population in northeastern Cambodia to estimate the density of calling groups. The properties of the estimator are assessed using a simulation study, in which a variety of survey designs are also investigated. We then present a new form of the SECR likelihood for multi-occasion data which accounts for the stochastic availability of animals. In the context of gibbon surveys this allows model-based estimation of the proportion of groups that produce territorial vocalisations on a given day, thereby enabling the density of groups, instead of the density of calling groups, to be estimated. We illustrate the performance of this new estimator by simulation. We show that it is possible to estimate density reliably from human acoustic detections of visually cryptic species using SECR methods. For gibbon surveys we also show that incorporating observers’ estimates of bearings to detected groups substantially improves estimator performance. Using the new form of the SECR likelihood we demonstrate that estimates of availability, in addition to population density and detection function parameters, can be obtained from multi-occasion data, and that the detection function parameters are not confounded with the availability parameter. This acoustic SECR method provides a means of obtaining reliable density estimates for territorial vocalising species. It is also efficient in terms of data requirements since since it only requires routine survey data. We anticipate that the low-tech field requirements will make this method

  12. Electron density measurement in gas discharge plasmas by optical and acoustic methods

    NASA Astrophysics Data System (ADS)

    Biagioni, A.; Anania, M. P.; Bellaveglia, M.; Chiadroni, E.; Cianchi, A.; Di Giovenale, D.; Di Pirro, G.; Ferrario, M.; Filippi, F.; Mostacci, A.; Pompili, R.; Shpakov, V.; Vaccarezza, C.; Villa, F.; Zigler, A.

    2016-08-01

    Plasma density represents a very important parameter for both laser wakefield and plasma wakefield acceleration, which use a gas-filled capillary plasma source. Several techniques can be used to measure the plasma density within a capillary discharge, which are mainly based on optical diagnostic methods, as for example the well-known spectroscopic method using the Stark broadening effect. In this work, we introduce a preliminary study on an alternative way to detect the plasma density, based on the shock waves produced by gas discharge in a capillary. Firstly, the measurements of the acoustic spectral content relative to the laser-induced plasmas by a solid target allowed us to understand the main properties of the acoustic waves produced during this kind of plasma generation; afterwards, we have extended such acoustic technique to the capillary plasma source in order to calibrate it by comparison with the stark broadening method.

  13. DECAF - Density Estimation for Cetaceans from Passive Acoustic Fixed Sensors

    DTIC Science & Technology

    2008-01-01

    whale density at AUTEC using single hydrophone data; • if time allows, estimation of humpback whale density at PMRF. Project investigators and...classifier for minke and humpback whales; he is also taking the lead on developing methods for estimating density from single fixed sensors, together...this was presented as a poster paper (Marques and Thomas 2008) at the International Statistical Ecology Conference in July 2008. The humpback whale

  14. Energy density and energy flow of magnetoplasmonic waves on graphene

    NASA Astrophysics Data System (ADS)

    Moradi, Afshin

    2017-03-01

    By means the linearized magnetohydrodynamic theory, expressions for energy density and energy flow are derived for the p-polarized surface magnetoplasmon polaritons on graphene in the Voigt configuration, where a static magnetic field is normal to the graphene surface. Numerical results show that the external magnetic field has significant impact on the energy density and energy transport velocity of magnetoplasmon waves in the long-wavelength region, while total power flow vary only weakly with magnetostatic field. The velocity of energy propagation is proved to be identical with group velocity of the surface waves.

  15. Array of piezoelectric wires in acoustic energy harvesting

    NASA Astrophysics Data System (ADS)

    Golestanyan, Edvin

    An acoustic energy harvesting mechanism to harvest a travelling sound wave at a low audible frequency (180 ˜ 200Hz) is further developed and studied both experimentally and numerically. The acoustic energy harvester in this study consists of a quarter-wavelength straight tube resonator and multiple piezoelectric oscillators in wire and plate shapes placed inside the tube. When the tube resonator is excited by an incident sound at its acoustic resonant frequency, the amplified acoustic pressure inside the tube drives the vibration motions of piezoelectric oscillators, resulting in generating electricity. It has been found that a single piezoelectric plate generates more power than a wire, but with placing in multiple-rows piezoelectric wires more power is produced. Parallel and series connections of multiple piezoelectric oscillators have also been studied and expressions for calculating optimum loading resistance have been presented. It has been found that the series connection generates more power than parallel connection. As the number of piezoelectric oscillators increases, the magnitude of the single loading resistance decreases. The decrease of loading resistance is more intense in multiple wires than in multiple plates and in parallel connection than in series connection.

  16. Loss-induced Enhanced Transmission in Anisotropic Density-near-zero Acoustic Metamaterials

    PubMed Central

    Shen, Chen; Jing, Yun

    2016-01-01

    Anisotropic density-near-zero (ADNZ) acoustic metamaterials are investigated theoretically and numerically in this paper and are shown to exhibit extraordinary transmission enhancement when material loss is induced. The enhanced transmission is due to the enhanced propagating and evanescent wave modes inside the ADNZ medium thanks to the interplay of near-zero density, material loss, and high wave impedance matching in the propagation direction. The equi-frequency contour (EFC) is used to reveal whether the propagating wave mode is allowed in ADNZ metamaterials. Numerical simulations based on plate-type acoustic metamaterials with different material losses were performed to demonstrate collimation and subwavelength imaging enabled by the induced loss in ADNZ media. This work provides a different way for manipulating acoustic waves. PMID:27885268

  17. Loss-induced Enhanced Transmission in Anisotropic Density-near-zero Acoustic Metamaterials

    NASA Astrophysics Data System (ADS)

    Shen, Chen; Jing, Yun

    2016-11-01

    Anisotropic density-near-zero (ADNZ) acoustic metamaterials are investigated theoretically and numerically in this paper and are shown to exhibit extraordinary transmission enhancement when material loss is induced. The enhanced transmission is due to the enhanced propagating and evanescent wave modes inside the ADNZ medium thanks to the interplay of near-zero density, material loss, and high wave impedance matching in the propagation direction. The equi-frequency contour (EFC) is used to reveal whether the propagating wave mode is allowed in ADNZ metamaterials. Numerical simulations based on plate-type acoustic metamaterials with different material losses were performed to demonstrate collimation and subwavelength imaging enabled by the induced loss in ADNZ media. This work provides a different way for manipulating acoustic waves.

  18. High Energy Density Film Capacitors (PREPRINT)

    DTIC Science & Technology

    2009-06-01

    capacitor film, and the test of our first generation prototype capacitors . II. HIGH-K POLYMER DIELECTRIC MATERIALS Commercial polypropylene (PP...metallized polypropylene energy storage capacitors ”, IEEE Trans. Plasma Sci., 30(5): 1939 (2002). [2] W. Clelland, et al., Paktron Division of...AFRL-RZ-WP-TP-2010-2127 HIGH ENERGY DENSITY FILM CAPACITORS (PREPRINT) Shihai Zhang, Brian Zellers, Jim Henrish, Shawn Rockey, and Dean

  19. A hydrophone prototype for ultra high energy neutrino acoustic detection

    NASA Astrophysics Data System (ADS)

    Cotrufo, A.; Plotnikov, A.; Yershova, O.; Anghinolfi, M.; Piombo, D.

    2009-06-01

    The design of an air-backed fiber-optic hydrophone is presented. With respect to the previous models this prototype is optimized to provide a bandwidth sufficiently large to detect acoustic signals produced by high energy hadronic showers in water. In addiction to the geometrical configuration and to the choice of the materials, the preliminary results of the measured performances in air are presented.

  20. Experimental characterization of active acoustic metamaterial cell with controllable dynamic density

    NASA Astrophysics Data System (ADS)

    Akl, Wael; Baz, Amr

    2012-10-01

    Controlling wave propagation pattern within acoustic fluid domains has been the motivation for the acoustic metamaterials developments to target applications ranging from acoustic cloaking to passive noise control techniques. Currently, various numerical and analytical approaches exist to predict the fluid domain material properties necessary for specific propagation pattern. Physical attempts to realize such material properties have revealed engineered material constructions that are focused on predefined wave propagation patterns. In the current paper, coupled fluid-structure one-dimensional metamaterial cell, in which piezoelectric active ingredient has been introduced, is manufactured to achieve controllable dynamic density. The density-controllable cell has been manufactured by coupling a water-filled cavity with piezoelectric elements in a cell of 4.5 cm length and 4.1 cm diameter subject to impulse excitation. A finite element model of the cell has been developed and its predictions are validated against the experimental results. The validated model is utilized to predict the changes in the pressure gradient inside the developed cell which is a direct measure of the changes introduced to the dynamic density of the acoustic metamaterial domain. With such predictions, it is demonstrated that densities as high as 3.2 gm/cm3 and as low as 0.72 gm/cm3 can be achieved experimentally for excitation frequencies ranging between 100 Hz and 500 Hz.

  1. Estimating cetacean population density using fixed passive acoustic sensors: an example with Blainville's beaked whales.

    PubMed

    Marques, Tiago A; Thomas, Len; Ward, Jessica; DiMarzio, Nancy; Tyack, Peter L

    2009-04-01

    Methods are developed for estimating the size/density of cetacean populations using data from a set of fixed passive acoustic sensors. The methods convert the number of detected acoustic cues into animal density by accounting for (i) the probability of detecting cues, (ii) the rate at which animals produce cues, and (iii) the proportion of false positive detections. Additional information is often required for estimation of these quantities, for example, from an acoustic tag applied to a sample of animals. Methods are illustrated with a case study: estimation of Blainville's beaked whale density over a 6 day period in spring 2005, using an 82 hydrophone wide-baseline array located in the Tongue of the Ocean, Bahamas. To estimate the required quantities, additional data are used from digital acoustic tags, attached to five whales over 21 deep dives, where cues recorded on some of the dives are associated with those received on the fixed hydrophones. Estimated density was 25.3 or 22.5 animals/1000 km(2), depending on assumptions about false positive detections, with 95% confidence intervals 17.3-36.9 and 15.4-32.9. These methods are potentially applicable to a wide variety of marine and terrestrial species that are hard to survey using conventional visual methods.

  2. 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.

  3. Cheap DECAF: Density Estimation for Cetaceans from Acoustic Fixed Sensors Using Separate, Non-Linked Devices

    DTIC Science & Technology

    2014-06-29

    Andrews have begun a new research effort with Penn State University, "Large Scale Density Estimation of Blue and Fin Whales ", funded by ONR. This...research groups that hold acoustic tag data for blue and fin whales and assist them in estimating cue rates that could be used in appropriate density...ABSTRACT Recordings of fin whales (Balaenoptera physalus) from a sparse array of Ocean Bottom Seismometers (OBSs) have been used to (1) demonstrate the use

  4. Theoretical and experimental study on the acoustic wave energy after the nonlinear interaction of acoustic waves in aqueous media

    NASA Astrophysics Data System (ADS)

    Lan, Chao-feng; Li, Feng-chen; Chen, Huan; Lu, Di; Yang, De-sen; Zhang, Meng

    2015-06-01

    Based on the Burgers equation and Manley-Rowe equation, the derivation about nonlinear interaction of the acoustic waves has been done in this paper. After nonlinear interaction among the low-frequency weak waves and the pump wave, the analytical solutions of acoustic waves' amplitude in the field are deduced. The relationship between normalized energy of high-frequency and the change of acoustic energy before and after the nonlinear interaction of the acoustic waves is analyzed. The experimental results about the changes of the acoustic energy are presented. The study shows that new frequencies are generated and the energies of the low-frequency are modulated in a long term by the pump waves, which leads the energies of the low-frequency acoustic waves to change in the pulse trend in the process of the nonlinear interaction of the acoustic waves. The increase and decrease of the energies of the low-frequency are observed under certain typical conditions, which lays a foundation for practical engineering applications.

  5. 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.

  6. Acoustic logging on ultralow density cement bonded quality evaluation in cased hole

    NASA Astrophysics Data System (ADS)

    Wang, H.; Shang, X.; Chen, T.; Tao, G.

    2011-12-01

    Cementing operation after drilling boreholes ensures oil and gas to be extracted effectively and avoids oil spill events such as BP Mexico oil leakage events. However, the loss of cement in deep formation due to its high density happens and raises issues. In order to overcome this problem, ultralow density cement or gas-based cements are used more and more commonly in recent years. Current acoustic evaluation tools, used to determine the cement bond quality, are designed for conventional high density cement. Therefore, they are not capable to image the ultralow density cement, whose acoustic properties are similar to borehole drilling mud. In this paper, a new acoustic technique is developed to image the ultralow density cement behind case. Finite difference method and analytical methods are used to simulate the wave-field of cased borehole which ultralow density cement bonded on. Based on the simulations, the optimal parameters of the evaluation tool design are proposed including spacing (from source to the nearest receiver and between the two neighboring receiver), frequency of source.

  7. Anomalous wave propagation in a one-dimensional acoustic metamaterial having simultaneously negative mass density and Young's modulus.

    PubMed

    Huang, H H; Sun, C T

    2012-10-01

    A mechanical model representing an acoustic metamaterial that exhibits simultaneously negative mass density and negative Young's modulus was proposed. Wave propagation was studied in the frequency range of double negativity. In view of positive energy flow, it was found that the phase velocity in this range is negative. This phenomenon was also observed using transient wave propagation finite-element analyses of a transient sinusoidal wave and a transient wave packet. In contrast to wave propagation in the region of positive mass and modulus, the peculiar backward wave motion in the region of double negativity was clearly displayed.

  8. Acoustic metamaterials capable of both sound insulation and energy harvesting

    NASA Astrophysics Data System (ADS)

    Li, Junfei; Zhou, Xiaoming; Huang, Guoliang; Hu, Gengkai

    2016-04-01

    Membrane-type acoustic metamaterials are well known for low-frequency sound insulation. In this work, by introducing a flexible piezoelectric patch, we propose sound-insulation metamaterials with the ability of energy harvesting from sound waves. The dual functionality of the metamaterial device has been verified by experimental results, which show an over 20 dB sound transmission loss and a maximum energy conversion efficiency up to 15.3% simultaneously. This novel property makes the metamaterial device more suitable for noise control applications.

  9. Alternative Approaches to High Energy Density Fusion

    NASA Astrophysics Data System (ADS)

    Hammer, J.

    2016-10-01

    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 NTF-like drive conditions and reach the energy bound for indirect drive ICF.

  10. 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.}

  11. 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.

  12. High Energy Density Polymer Film Capacitors

    DTIC Science & Technology

    2006-10-01

    are formed by vapor deposition of multifunctional acrylate monomers that are deposited on the PVDF as a thin liquid film and are cross linked using...the world. Vacuum Depositing Inc. American Thin Films Vapor Technologies Inc. 1294 Old Fern Valley Road 2010 East Hennepin Ave. Boulder Tech Center...78 5.5.1 Capacitors Values, Voltage Breakdown, and Energy Density ................ 79 APPENDIX A PVDF AND PET FILMS

  13. Note: High-efficiency broadband acoustic energy harvesting using Helmholtz resonator and dual piezoelectric cantilever beams

    SciTech Connect

    Yang, Aichao; Li, Ping Wen, Yumei; Lu, Caijiang; Peng, Xiao; He, Wei; Zhang, Jitao; Wang, Decai; Yang, Feng

    2014-06-15

    A high-efficiency broadband acoustic energy harvester consisting of a compliant-top-plate Helmholtz resonator (HR) and dual piezoelectric cantilever beams is proposed. Due to the high mechanical quality factor of beams and the strong multimode coupling of HR cavity, top plate and beams, the high efficiency in a broad bandwidth is obtained. Experiment exhibits that the proposed harvester at 170–206 Hz has 28–188 times higher efficiency than the conventional harvester using a HR with a piezoelectric composite diaphragm. For input acoustic pressure of 2.0 Pa, the proposed harvester exhibits 0.137–1.43 mW output power corresponding to 0.035–0.36 μW cm{sup −3} volume power density at 170–206 Hz.

  14. Note: High-efficiency broadband acoustic energy harvesting using Helmholtz resonator and dual piezoelectric cantilever beams.

    PubMed

    Yang, Aichao; Li, Ping; Wen, Yumei; Lu, Caijiang; Peng, Xiao; He, Wei; Zhang, Jitao; Wang, Decai; Yang, Feng

    2014-06-01

    A high-efficiency broadband acoustic energy harvester consisting of a compliant-top-plate Helmholtz resonator (HR) and dual piezoelectric cantilever beams is proposed. Due to the high mechanical quality factor of beams and the strong multimode coupling of HR cavity, top plate and beams, the high efficiency in a broad bandwidth is obtained. Experiment exhibits that the proposed harvester at 170-206 Hz has 28-188 times higher efficiency than the conventional harvester using a HR with a piezoelectric composite diaphragm. For input acoustic pressure of 2.0 Pa, the proposed harvester exhibits 0.137-1.43 mW output power corresponding to 0.035-0.36 μW cm(-3) volume power density at 170-206 Hz.

  15. Device and method for generating a beam of acoustic energy from a borehole, and applications thereof

    SciTech Connect

    Vu, Cung Khac; Sinha, Dipen N; Pantea, Cristian; Nihei, Kurt T; Schmitt, Denis P; Skelt, Christopher

    2013-10-01

    In some aspects of the invention, a method of generating a beam of acoustic energy in a borehole is disclosed. The method includes generating a first acoustic wave at a first frequency; generating a second acoustic wave at a second frequency different than the first frequency, wherein the first acoustic wave and second acoustic wave are generated by at least one transducer carried by a tool located within the borehole; transmitting the first and the second acoustic waves into an acoustically non-linear medium, wherein the composition of the non-linear medium produces a collimated beam by a non-linear mixing of the first and second acoustic waves, wherein the collimated beam has a frequency based upon a difference between the first frequency and the second frequency; and transmitting the collimated beam through a diverging acoustic lens to compensate for a refractive effect caused by the curvature of the borehole.

  16. Cetacean Density Estimation from Novel Acoustic Datasets by Acoustic Propagation Modeling

    DTIC Science & Technology

    2012-09-30

    not observed in Atlantic bottlenose dolphins and beluga whales for example. The beams were observed to be directed forward between 0˚ and -5˚ in the...data set, collected by a single hydrophone, to estimate the population density of false killer whales (Pseudorca crassidens) off of the Kona coast of...incorporate accurate modeling of sound propagation due to the complexities of its environment. Moreover, the target species chosen for the proposed

  17. Cetacean Density Estimation from Novel Acoustic Datasets by Acoustic Propagation Modeling

    DTIC Science & Technology

    2014-09-30

    hydrophone, to estimate the population density of false killer whales (Pseudorca crassidens) off of the Kona coast of the Island of Hawai’i... killer whale, suffers from interaction with the fisheries industry and its population has been reported to have declined in the past 20 years. Studies...of abundance estimate of false killer whales in Hawai’i through mark recapture methods will provide comparable results to the ones obtained by this

  18. An Energy Harvesting Underwater Acoustic Transmitter for Aquatic Animals

    PubMed Central

    Li, Huidong; Tian, Chuan; Lu, Jun; Myjak, Mitchell J.; Martinez, Jayson J.; Brown, Richard S.; Deng, Zhiqun Daniel

    2016-01-01

    Acoustic telemetry is the primary method to actively track aquatic animals for behavioral studies. However, the small storage capacities of the batteries used in the transmitters limit the time that the implanted animals can be studied. In this research, we developed and implemented a battery-free acoustic transmitter that uses a flexible piezoelectric beam to harvest energy from fish swimming as the power source. The transmitter sends out a unique identification code with a sufficiently strong signal (150 dB, ref: 1 μPa at 1 meter) that has a detection range of up to 100 meters. Two prototypes, 100 mm and 77 mm long, respectively, weighing only about 1 gram or less in air, were sub-dermally implanted in two species of live fish. Transmissions were successfully detected as the fish swam in a natural manner. This represents the first known implanted energy-harvesting transmitter demonstrated in vivo. Successful development of this transmitter greatly expands the potential for long-term studies of the behaviors of aquatic animals and for subsequently developing strategies to mitigate the environmental impacts of renewable energy systems. PMID:27647426

  19. An Energy Harvesting Underwater Acoustic Transmitter for Aquatic Animals

    NASA Astrophysics Data System (ADS)

    Li, Huidong; Tian, Chuan; Lu, Jun; Myjak, Mitchell J.; Martinez, Jayson J.; Brown, Richard S.; Deng, Zhiqun Daniel

    2016-09-01

    Acoustic telemetry is the primary method to actively track aquatic animals for behavioral studies. However, the small storage capacities of the batteries used in the transmitters limit the time that the implanted animals can be studied. In this research, we developed and implemented a battery-free acoustic transmitter that uses a flexible piezoelectric beam to harvest energy from fish swimming as the power source. The transmitter sends out a unique identification code with a sufficiently strong signal (150 dB, ref: 1 μPa at 1 meter) that has a detection range of up to 100 meters. Two prototypes, 100 mm and 77 mm long, respectively, weighing only about 1 gram or less in air, were sub-dermally implanted in two species of live fish. Transmissions were successfully detected as the fish swam in a natural manner. This represents the first known implanted energy-harvesting transmitter demonstrated in vivo. Successful development of this transmitter greatly expands the potential for long-term studies of the behaviors of aquatic animals and for subsequently developing strategies to mitigate the environmental impacts of renewable energy systems.

  20. Considerations on the acoustic energy radiated by toothed gears. [model for calculating noise intensity

    NASA Technical Reports Server (NTRS)

    Popinceanu, N. G.; Kremmer, I.

    1974-01-01

    A mechano-acoustic model is reported for calculating acoustic energy radiated by a working gear. According to this model, a gear is an acoustic coublet formed of the two wheels. The wheel teeth generate cylindrical acoustic waves while the front surfaces of the teeth behave like vibrating pistons. Theoretical results are checked experimentally and good agreement is obtained with open gears. The experiments show that the air noise effect is negligible as compared with the structural noise transmitted to the gear box.

  1. Characterization of structural vibration: Field descriptors based on energy density and intensity

    NASA Astrophysics Data System (ADS)

    Linjama, Jukka

    Measurement of energy flow in acoustical and vibrational fields is usually based on the detection of one linear field quantity (e.g. sound pressure) and its spatial gradient, two transducers being used for the measurement. This report first reviews the quantities which can be obtained from the measurement of acoustical intensity with a two-microphone probe: intensity and the energy densities. A set of 'field descriptors', relative quantities giving a measure of propagating (active) character of the waves in the sound field, is proposed. These energetic quantities are based entirely on the transversal velocity measured and the gradient of that velocity, and are available when the two-transducer method of bending wave intensity is used. Examples of the energy densities and field descriptors measured in an aluminum plate are presented, and proposals for further work are given.

  2. A Large-Aperture Acoustic Array to Observe Oceanic Density Structure

    DTIC Science & Technology

    1975-12-01

    Subtitle) ._,,, , , : A ^ARGE-APERTURb ^ COUSTIC ARRAY TO ^OBSERVE OCEANIC DENSITY STRUCTURE t 7. AUTHORfj; G. Thomas/Kaye READ INSTRUCTIONS...o CO (M MARINE PHYSICAL LABORATORY of the Scripps Institution of Oceanography San Diego, California 92132 A LARGE APERTURE ACOUSTIC ARRAY TO...Contracts Contract Effective Date: Contract Expiration Date; Amount of Contract: Layered Inhomogeneities N00014-69- A -0200-6038 \\ 1 April 1972 Jiß

  3. 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.

  4. 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.

  5. Distribution of lateral acoustic energy in Mudejar Gothic churches

    NASA Astrophysics Data System (ADS)

    Girón, S.; Galindo, M.; Zamarreño, T.

    2008-09-01

    In this work, the physical measures of spatial impression are considered in 12 Mudejar-Gothic churches in the city of Seville in the south of Spain. This study describes the spatial distribution of the early and late lateral acoustic energy, through monaural parameters derived from impulse response analysis using a maximum length sequence measurement system in each church. In the first time analysis, the two early lateral energy measures, early lateral fraction (LF) and early lateral fraction cosine (LFC) are taken in order to assess apparent source width (ASW), and the late lateral level (GLL) in the second to assess listener envelopment (LEV) are conducted. Parameters have been studied spectrally in each temple and were averaged at low- and mid-frequency values in their different naves in order to study how these two attributes of sound perception vary with source-receiver distance. Experimental results have been compared with the theoretical early lateral energy fractions and late lateral level, both of which are derived by assuming that reflected energy in these places of worship is solely dependent on source-receiver distance. This comparison is carried out in accordance with the μ-model proposed by the authors in an earlier paper in order to describe the dependence of acoustic monaural omnidirectional energy parameters on source-receiver distance. Thus, it is supposed that the directional distribution of reflections is similar to a diffuse distribution. To conclude, these spatially averaged monoaural parameters have been correlated with geometric variables by using linear regression and only weak correlations with the mean width of the churches and with the height/width ratio have been found.

  6. High energy density redox flow device

    SciTech Connect

    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.

  7. 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.

  8. Device and method for generating a beam of acoustic energy from a borehole, and applications thereof

    SciTech Connect

    Vu, Cung Khac; Sinha, Dipen N.; Pantea, Cristian; Nihei, Kurt T.; Schmitt, Denis P.; Skelt, Chirstopher

    2013-10-15

    In some aspects of the invention, a method of generating a beam of acoustic energy in a borehole is disclosed. The method includes generating a first acoustic wave at a first frequency; generating a second acoustic wave at a second frequency different than the first frequency, wherein the first acoustic wave and second acoustic wave are generated by at least one transducer carried by a tool located within the borehole; transmitting the first and the second acoustic waves into an acoustically non-linear medium, wherein the composition of the non-linear medium produces a collimated beam by a non-linear mixing of the first and second acoustic waves, wherein the collimated beam has a frequency based upon a difference between the first frequency range and the second frequency, and wherein the non-linear medium has a velocity of sound between 100 m/s and 800 m/s.

  9. 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

  10. Energy-Efficient Channel Coding Strategy for Underwater Acoustic Networks.

    PubMed

    Barreto, Grasielli; Simão, Daniel H; Pellenz, Marcelo E; Souza, Richard D; Jamhour, Edgard; Penna, Manoel C; Brante, Glauber; Chang, Bruno S

    2017-03-31

    Underwater acoustic networks (UAN) allow for efficiently exploiting and monitoring the sub-aquatic environment. These networks are characterized by long propagation delays, error-prone channels and half-duplex communication. In this paper, we address the problem of energy-efficient communication through the use of optimized channel coding parameters. We consider a two-layer encoding scheme employing forward error correction (FEC) codes and fountain codes (FC) for UAN scenarios without feedback channels. We model and evaluate the energy consumption of different channel coding schemes for a K-distributed multipath channel. The parameters of the FEC encoding layer are optimized by selecting the optimal error correction capability and the code block size. The results show the best parameter choice as a function of the link distance and received signal-to-noise ratio.

  11. Nonlinear effects of dark energy clustering beyond the acoustic scales

    SciTech Connect

    Anselmi, Stefano; Sefusatti, Emiliano E-mail: dlopez_n@ictp.it

    2014-07-01

    We extend the resummation method of Anselmi and Pietroni (2012) to compute the total density power spectrum in models of quintessence characterized by a vanishing speed of sound. For standard ΛCDM cosmologies, this resummation scheme allows predictions with an accuracy at the few percent level beyond the range of scales where acoustic oscillations are present, therefore comparable to other, common numerical tools. In addition, our theoretical approach indicates an approximate but valuable and simple relation between the power spectra for standard quintessence models and models where scalar field perturbations appear at all scales. This, in turn, provides an educated guess for the prediction of nonlinear growth in models with generic speed of sound, particularly valuable since no numerical results are yet available.

  12. 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.

  13. 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.

  14. 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.

  15. Effects of Acoustic Emission and Energy Evolution of Rock Specimens Under the Uniaxial Cyclic Loading and Unloading Compression

    NASA Astrophysics Data System (ADS)

    Meng, Qingbin; Zhang, Mingwei; Han, Lijun; Pu, Hai; Nie, Taoyi

    2016-10-01

    Characteristics of energy accumulation, evolution, and dissipation in uniaxial cyclic loading and unloading compression of 30 sandstone rock specimens under six different loading rates were explored. Stress-strain relations and acoustic emission characteristics of the deformation and failure of rock specimens were analyzed. The densities and rates of stored energy, elastic energy, and dissipated energy under different loading rates were confirmed, and an effective approach for the equivalent energy surface was presented. The energy evolution of rock deformation and failure were revealed. It turns out that the rock deformation behavior under uniaxial cyclic loading and unloading compression remained almost unchanged compared with that of uniaxial compression. The degree of match between reloading stress-strain curves and previous unloading curves was high, thereby demonstrating the memory function of rock masses. The intensity of acoustic emission fluctuated continually during the entire cyclic process. Emissions significantly increased as the stress exceeded the unloading level. The peak of acoustic emission increased with increasing loading stress level. Relationships between energy density and axial load indicate that the rock mass possesses a certain energy storage limitation. The energy evolution of rock masses is closely related to the axial loading stress, rather than to the axial loading rate. With increasing axial loading stress, stored energy varied most rapidly, followed by that of the elastic energy, then dissipated energy. Energy accumulation dominates prior to the axial load reaching peak strength; thereafter, energy dissipation becomes dominant. The input energy causes the irreversible initiation and extension of microcracks in the rock body. Elastic energy release leads to sudden instability of rock bodies and drives rock damage.

  16. 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

  17. 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.

  18. Cetacean population density estimation from single fixed sensors using passive acoustics.

    PubMed

    Küsel, Elizabeth T; Mellinger, David K; Thomas, Len; Marques, Tiago A; Moretti, David; Ward, Jessica

    2011-06-01

    Passive acoustic methods are increasingly being used to estimate animal population density. Most density estimation methods are based on estimates of the probability of detecting calls as functions of distance. Typically these are obtained using receivers capable of localizing calls or from studies of tagged animals. However, both approaches are expensive to implement. The approach described here uses a MonteCarlo model to estimate the probability of detecting calls from single sensors. The passive sonar equation is used to predict signal-to-noise ratios (SNRs) of received clicks, which are then combined with a detector characterization that predicts probability of detection as a function of SNR. Input distributions for source level, beam pattern, and whale depth are obtained from the literature. Acoustic propagation modeling is used to estimate transmission loss. Other inputs for density estimation are call rate, obtained from the literature, and false positive rate, obtained from manual analysis of a data sample. The method is applied to estimate density of Blainville's beaked whales over a 6-day period around a single hydrophone located in the Tongue of the Ocean, Bahamas. Results are consistent with those from previous analyses, which use additional tag data.

  19. Acoustic energy relations in Mudejar-Gothic churches.

    PubMed

    Zamarreño, Teófilo; Girón, Sara; Galindo, Miguel

    2007-01-01

    Extensive objective energy-based parameters have been measured in 12 Mudejar-Gothic churches in the south of Spain. Measurements took place in unoccupied churches according to the ISO-3382 standard. Monoaural objective measures in the 125-4000 Hz frequency range and in their spatial distributions were obtained. Acoustic parameters: clarity C80, definition D50, sound strength G and center time Ts have been deduced using impulse response analysis through a maximum length sequence measurement system in each church. These parameters spectrally averaged according to the most extended criteria in auditoria in order to consider acoustic quality were studied as a function of source-receiver distance. The experimental results were compared with predictions given by classical and other existing theoretical models proposed for concert halls and churches. An analytical semi-empirical model based on the measured values of the C80 parameter is proposed in this work for these spaces. The good agreement between predicted values and experimental data for definition, sound strength, and center time in the churches analyzed shows that the model can be used for design predictions and other purposes with reasonable accuracy.

  20. 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.

  1. 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.

  2. Opportunities for shear energy scaling in bulk acoustic wave resonators.

    PubMed

    Jose, Sumy; Hueting, Raymond J E

    2014-10-01

    An important energy loss contribution in bulk acoustic wave resonators is formed by so-called shear waves, which are transversal waves that propagate vertically through the devices with a horizontal motion. In this work, we report for the first time scaling of the shear-confined spots, i.e., spots containing a high concentration of shear wave displacement, controlled by the frame region width at the edge of the resonator. We also demonstrate a novel methodology to arrive at an optimum frame region width for spurious mode suppression and shear wave confinement. This methodology makes use of dispersion curves obtained from finite-element method (FEM) eigenfrequency simulations for arriving at an optimum frame region width. The frame region optimization is demonstrated for solidly mounted resonators employing several shear wave optimized reflector stacks. Finally, the FEM simulation results are compared with measurements for resonators with Ta2O5/ SiO2 stacks showing suppression of the spurious modes.

  3. Statistical properties of kinetic and total energy densities in reverberant spaces.

    PubMed

    Jacobsen, Finn; Molares, Alfonso Rodríguez

    2010-04-01

    Many acoustical measurements, e.g., measurement of sound power and transmission loss, rely on determining the total sound energy in a reverberation room. The total energy is usually approximated by measuring the mean-square pressure (i.e., the potential energy density) at a number of discrete positions. The idea of measuring the total energy density instead of the potential energy density on the assumption that the former quantity varies less with position than the latter goes back to the 1930s. However, the phenomenon was not analyzed until the late 1970s and then only for the region of high modal overlap, and this analysis has never been published. Moreover, until fairly recently, measurement of the total sound energy density required an elaborate experimental arrangement based on finite-difference approximations using at least four amplitude and phase matched pressure microphones. With the advent of a three-dimensional particle velocity transducer, it has become somewhat easier to measure total rather than only potential energy density in a sound field. This paper examines the ensemble statistics of kinetic and total sound energy densities in reverberant enclosures theoretically, experimentally, and numerically.

  4. Efficient Structure Resonance Energy Transfer from Microwaves to Confined Acoustic Vibrations in Viruses.

    PubMed

    Yang, Szu-Chi; Lin, Huan-Chun; Liu, Tzu-Ming; Lu, Jen-Tang; Hung, Wan-Ting; Huang, Yu-Ru; Tsai, Yi-Chun; Kao, Chuan-Liang; Chen, Shih-Yuan; Sun, Chi-Kuang

    2015-12-09

    Virus is known to resonate in the confined-acoustic dipolar mode with microwave of the same frequency. However this effect was not considered in previous virus-microwave interaction studies and microwave-based virus epidemic prevention. Here we show that this structure-resonant energy transfer effect from microwaves to virus can be efficient enough so that airborne virus was inactivated with reasonable microwave power density safe for the open public. We demonstrate this effect by measuring the residual viral infectivity of influenza A virus after illuminating microwaves with different frequencies and powers. We also established a theoretical model to estimate the microwaves power threshold for virus inactivation and good agreement with experiments was obtained. Such structure-resonant energy transfer induced inactivation is mainly through physically fracturing the virus structure, which was confirmed by real-time reverse transcription polymerase chain reaction. These results provide a pathway toward establishing a new epidemic prevention strategy in open public for airborne virus.

  5. Efficient Structure Resonance Energy Transfer from Microwaves to Confined Acoustic Vibrations in Viruses

    NASA Astrophysics Data System (ADS)

    Yang, Szu-Chi; Lin, Huan-Chun; Liu, Tzu-Ming; Lu, Jen-Tang; Hung, Wan-Ting; Huang, Yu-Ru; Tsai, Yi-Chun; Kao, Chuan-Liang; Chen, Shih-Yuan; Sun, Chi-Kuang

    2015-12-01

    Virus is known to resonate in the confined-acoustic dipolar mode with microwave of the same frequency. However this effect was not considered in previous virus-microwave interaction studies and microwave-based virus epidemic prevention. Here we show that this structure-resonant energy transfer effect from microwaves to virus can be efficient enough so that airborne virus was inactivated with reasonable microwave power density safe for the open public. We demonstrate this effect by measuring the residual viral infectivity of influenza A virus after illuminating microwaves with different frequencies and powers. We also established a theoretical model to estimate the microwaves power threshold for virus inactivation and good agreement with experiments was obtained. Such structure-resonant energy transfer induced inactivation is mainly through physically fracturing the virus structure, which was confirmed by real-time reverse transcription polymerase chain reaction. These results provide a pathway toward establishing a new epidemic prevention strategy in open public for airborne virus.

  6. Passive acoustic monitoring of beaked whale densities in the Gulf of Mexico.

    PubMed

    Hildebrand, John A; Baumann-Pickering, Simone; Frasier, Kaitlin E; Trickey, Jennifer S; Merkens, Karlina P; Wiggins, Sean M; McDonald, Mark A; Garrison, Lance P; Harris, Danielle; Marques, Tiago A; Thomas, Len

    2015-11-12

    Beaked whales are deep diving elusive animals, difficult to census with conventional visual surveys. Methods are presented for the density estimation of beaked whales, using passive acoustic monitoring data collected at sites in the Gulf of Mexico (GOM) from the period during and following the Deepwater Horizon oil spill (2010-2013). Beaked whale species detected include: Gervais' (Mesoplodon europaeus), Cuvier's (Ziphius cavirostris), Blainville's (Mesoplodon densirostris) and an unknown species of Mesoplodon sp. (designated as Beaked Whale Gulf - BWG). For Gervais' and Cuvier's beaked whales, we estimated weekly animal density using two methods, one based on the number of echolocation clicks, and another based on the detection of animal groups during 5 min time-bins. Density estimates derived from these two methods were in good general agreement. At two sites in the western GOM, Gervais' beaked whales were present throughout the monitoring period, but Cuvier's beaked whales were present only seasonally, with periods of low density during the summer and higher density in the winter. At an eastern GOM site, both Gervais' and Cuvier's beaked whales had a high density throughout the monitoring period.

  7. Passive acoustic monitoring of beaked whale densities in the Gulf of Mexico

    PubMed Central

    Hildebrand, John A.; Baumann-Pickering, Simone; Frasier, Kaitlin E.; Trickey, Jennifer S.; Merkens, Karlina P.; Wiggins, Sean M.; McDonald, Mark A.; Garrison, Lance P.; Harris, Danielle; Marques, Tiago A.; Thomas, Len

    2015-01-01

    Beaked whales are deep diving elusive animals, difficult to census with conventional visual surveys. Methods are presented for the density estimation of beaked whales, using passive acoustic monitoring data collected at sites in the Gulf of Mexico (GOM) from the period during and following the Deepwater Horizon oil spill (2010–2013). Beaked whale species detected include: Gervais’ (Mesoplodon europaeus), Cuvier’s (Ziphius cavirostris), Blainville’s (Mesoplodon densirostris) and an unknown species of Mesoplodon sp. (designated as Beaked Whale Gulf — BWG). For Gervais’ and Cuvier’s beaked whales, we estimated weekly animal density using two methods, one based on the number of echolocation clicks, and another based on the detection of animal groups during 5 min time-bins. Density estimates derived from these two methods were in good general agreement. At two sites in the western GOM, Gervais’ beaked whales were present throughout the monitoring period, but Cuvier’s beaked whales were present only seasonally, with periods of low density during the summer and higher density in the winter. At an eastern GOM site, both Gervais’ and Cuvier’s beaked whales had a high density throughout the monitoring period. PMID:26559743

  8. Compact transformable acoustic logic gates for broadband complex Boolean operations based on density-near-zero metamaterials

    NASA Astrophysics Data System (ADS)

    Zhang, Ting; Cheng, Ying; Yuan, Bao-Guo; Guo, Jian-Zhong; Liu, Xiao-Jun

    2016-05-01

    The extraordinary transmission in density-near-zero (DNZ) acoustic metamaterials (AMs) provides possibilities to manipulate acoustic signals with extremely large effective phase velocity and wavelength. Here, we report compact transformable acoustic logic gates with a subwavelength size as small as 0.82λ based on DNZ AMs. The basic acoustic logic gates, composed of a tri-port structure filled with space-coiling DNZ AMs, enable precise direct linear interference of input signals with considerably small phase lag and wavefront distortion. We demonstrate both theoretically and experimentally the basic Boolean logic operations such as OR, AND, XOR, and NOT with wide operational frequency ranges and controllability, by adjusting the phase difference between two input signals. More complex logic calculus, such as "I1 + I2 × I3," are also realized by cascading of the basic logic gates. Our proposal provides diverse routes to construct devices for acoustic signal computing and manipulations.

  9. Comparison of Numerical Models for Vibro-Acoustic Analysis of Structural Panels in Low Modal Density Range Engaging Air Layers

    NASA Astrophysics Data System (ADS)

    Chimeno-Manguan, M.; Martinz-Calvo, B.; Roibas-Millan, E.; Fajardo, P.; Simon, F.; Lopez-Diez, J.

    2012-07-01

    During launch, satellite and their equipment are subjected to loads of random nature and with a wide frequency range. Their vibro-acoustic response is an important issue to be analysed, for example for folded solar arrays and antennas. The main issue at low modal density is the modelling combinations engaging air layers, structures and external fluid. Depending on the modal density different methodologies, as FEM, BEM and SEA should be considered. This work focuses on the analysis of different combinations of the methodologies previously stated used in order to characterise the vibro-acoustic response of two rectangular sandwich structure panels isolated and engaging an air layer between them under a diffuse acoustic field. Focusing on the modelling of air layers, different models are proposed. To illustrate the phenomenology described and studied, experimental results from an acoustic test on an ARA-MKIII solar array in folded configuration are presented along with numerical results.

  10. 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.

  11. Meta-atom cluster acoustic metamaterial with broadband negative effective mass density

    SciTech Connect

    Chen, Huaijun; Zhai, Shilong; Ding, Changlin; Liu, Song; Luo, Chunrong; Zhao, Xiaopeng

    2014-02-07

    We design a resonant meta-atom cluster, via which a two-dimensional (2D) acoustic metamaterial (AM) with broadband negative effective mass density from 1560 Hz to 5580 Hz is fabricated. Experimental results confirm that there is only weak interaction among the meta-atoms in the cluster. And then the meta-atoms in the cluster independently resonate, resulting in the cluster becoming equivalent to a broadband resonance unit. Extracted effective refractive indices from reflection and transmission measurements of the 2D AM appear to be negative from 1500 Hz to 5480 Hz. The broadband negative refraction has also been demonstrated by our further experiments. We expect that this meta-atom cluster AM will significantly contribute to the design of broadband negative effective mass density AM.

  12. Linearized acoustic perturbation equations for low Mach number flow with variable density and temperature

    NASA Astrophysics Data System (ADS)

    Munz, Claus-Dieter; Dumbser, Michael; Roller, Sabine

    2007-05-01

    When the Mach number tends to zero the compressible Navier-Stokes equations converge to the incompressible Navier-Stokes equations, under the restrictions of constant density, constant temperature and no compression from the boundary. This is a singular limit in which the pressure of the compressible equations converges at leading order to a constant thermodynamic background pressure, while a hydrodynamic pressure term appears in the incompressible equations as a Lagrangian multiplier to establish the divergence-free condition for the velocity. In this paper we consider the more general case in which variable density, variable temperature and heat transfer are present, while the Mach number is small. We discuss first the limit equations for this case, when the Mach number tends to zero. The introduction of a pressure splitting into a thermodynamic and a hydrodynamic part allows the extension of numerical methods to the zero Mach number equations in these non-standard situations. The solution of these equations is then used as the state of expansion extending the expansion about incompressible flow proposed by Hardin and Pope [J.C. Hardin, D.S. Pope, An acoustic/viscous splitting technique for computational aeroacoustics, Theor. Comput. Fluid Dyn. 6 (1995) 323-340]. The resulting linearized equations state a mathematical model for the generation and propagation of acoustic waves in this more general low Mach number regime and may be used within a hybrid aeroacoustic approach.

  13. Tracking Energy Flow Using a Volumetric Acoustic Intensity Imager (VAIM)

    NASA Technical Reports Server (NTRS)

    Klos, Jacob; Williams, Earl G.; Valdivia, Nicolas P.

    2006-01-01

    A new measurement device has been invented at the Naval Research Laboratory which images instantaneously the intensity vector throughout a three-dimensional volume nearly a meter on a side. The measurement device consists of a nearly transparent spherical array of 50 inexpensive microphones optimally positioned on an imaginary spherical surface of radius 0.2m. Front-end signal processing uses coherence analysis to produce multiple, phase-coherent holograms in the frequency domain each related to references located on suspect sound sources in an aircraft cabin. The analysis uses either SVD or Cholesky decomposition methods using ensemble averages of the cross-spectral density with the fixed references. The holograms are mathematically processed using spherical NAH (nearfield acoustical holography) to convert the measured pressure field into a vector intensity field in the volume of maximum radius 0.4 m centered on the sphere origin. The utility of this probe is evaluated in a detailed analysis of a recent in-flight experiment in cooperation with Boeing and NASA on NASA s Aries 757 aircraft. In this experiment the trim panels and insulation were removed over a section of the aircraft and the bare panels and windows were instrumented with accelerometers to use as references for the VAIM. Results show excellent success at locating and identifying the sources of interior noise in-flight in the frequency range of 0 to 1400 Hz. This work was supported by NASA and the Office of Naval Research.

  14. Density, ultrasound velocity, acoustic impedance, reflection and absorption coefficient determination of liquids via multiple reflection method.

    PubMed

    Hoche, S; Hussein, M A; Becker, T

    2015-03-01

    The accuracy of density, reflection coefficient, and acoustic impedance determination via multiple reflection method was validated experimentally. The ternary system water-maltose-ethanol was used to execute a systematic, temperature dependent study over a wide range of densities and viscosities aiming an application as inline sensor in beverage industries. The validation results of the presented method and setup show root mean square errors of: 1.201E-3 g cm(-3) (±0.12%) density, 0.515E-3 (0.15%) reflection coefficient and 1.851E+3 kg s(-1) m(-2) (0.12%) specific acoustic impedance. The results of the diffraction corrected absorption showed an average standard deviation of only 0.12%. It was found that the absorption change shows a good correlation to concentration variations and may be useful for laboratory analysis of sufficiently pure liquids. The main part of the observed errors can be explained by the observed noise, temperature variation and the low signal resolution of 50 MHz. In particular, the poor signal-to-noise ratio of the second reflector echo was found to be a main accuracy limitation. Concerning the investigation of liquids the unstable properties of the reference material PMMA, due to hygroscopicity, were identified to be an additional, unpredictable source of uncertainty. While dimensional changes can be considered by adequate methodology, the impact of the time and temperature dependent water absorption on relevant reference properties like the buffer's sound velocity and density could not be considered and may explain part of the observed deviations.

  15. Simulation of the Acoustic Pulse Expected from the Interaction of Ultra-High Energy Neutrinos and Seawater

    DTIC Science & Technology

    2006-03-01

    Acoustic Ultra-high energy Neutrino Detection (SAUND), that uses existing hydrophone arrays to detect UHE neutrinos from the acoustic pulse generated by...Ultra-High Energy (UHE) neutrino and seawater. When a neutrino interacts with seawater, the reaction creates a long, narrow shower of sub-atomic...particles. The energy from this reaction causes nearly instantaneous heating of the seawater on an acoustic timescale. The acoustic pulse created by the

  16. [Estimation of age-related features of acoustic density and biometric relations of lens based on combined ultrasound scanning].

    PubMed

    Avetisov, K S; Markosian, A G

    2013-01-01

    Results of combined ultrasound scanning for estimation of acoustic lens density and biometric relations of lens and other eye structures are presented. A group of 124 patients (189 eyes) was studied; they were subdivided depending on age and length of anteroposterior axis of the eye. Examination algorithm was developed that allows selective estimation of acoustic density of different lens zones and biometric measurements including volumetric. Age-related increase of acoustic density of different lens zones was revealed that indirectly shows method efficiency. Biometric studies showed almost concurring volumetric lens measurements in "normal" and "short" eyes in spite of significantly thicker central zone of the latter. Significantly lower correlation between anterior chamber volume and width of its angle was revealed in "short" eyes and "normal" and "long" eyes (correlation coefficients 0.37, 0.68 and 0.63 respectively).

  17. Acoustics

    NASA Technical Reports Server (NTRS)

    Goodman, Jerry R.; Grosveld, Ferdinand

    2007-01-01

    The acoustics environment in space operations is important to maintain at manageable levels so that the crewperson can remain safe, functional, effective, and reasonably comfortable. High acoustic levels can produce temporary or permanent hearing loss, or cause other physiological symptoms such as auditory pain, headaches, discomfort, strain in the vocal cords, or fatigue. Noise is defined as undesirable sound. Excessive noise may result in psychological effects such as irritability, inability to concentrate, decrease in productivity, annoyance, errors in judgment, and distraction. A noisy environment can also result in the inability to sleep, or sleep well. Elevated noise levels can affect the ability to communicate, understand what is being said, hear what is going on in the environment, degrade crew performance and operations, and create habitability concerns. Superfluous noise emissions can also create the inability to hear alarms or other important auditory cues such as an equipment malfunctioning. Recent space flight experience, evaluations of the requirements in crew habitable areas, and lessons learned (Goodman 2003; Allen and Goodman 2003; Pilkinton 2003; Grosveld et al. 2003) show the importance of maintaining an acceptable acoustics environment. This is best accomplished by having a high-quality set of limits/requirements early in the program, the "designing in" of acoustics in the development of hardware and systems, and by monitoring, testing and verifying the levels to ensure that they are acceptable.

  18. Site specific passive acoustic detection and densities of humpback whale calls off the coast of California

    NASA Astrophysics Data System (ADS)

    Helble, Tyler Adam

    Passive acoustic monitoring of marine mammal calls is an increasingly important method for assessing population numbers, distribution, and behavior. Automated methods are needed to aid in the analyses of the recorded data. When a mammal vocalizes in the marine environment, the received signal is a filtered version of the original waveform emitted by the marine mammal. The waveform is reduced in amplitude and distorted due to propagation effects that are influenced by the bathymetry and environment. It is important to account for these effects to determine a site-specific probability of detection for marine mammal calls in a given study area. A knowledge of that probability function over a range of environmental and ocean noise conditions allows vocalization statistics from recordings of single, fixed, omnidirectional sensors to be compared across sensors and at the same sensor over time with less bias and uncertainty in the results than direct comparison of the raw statistics. This dissertation focuses on both the development of new tools needed to automatically detect humpback whale vocalizations from single-fixed omnidirectional sensors as well as the determination of the site-specific probability of detection for monitoring sites off the coast of California. Using these tools, detected humpback calls are "calibrated" for environmental properties using the site-specific probability of detection values, and presented as call densities (calls per square kilometer per time). A two-year monitoring effort using these calibrated call densities reveals important biological and ecological information on migrating humpback whales off the coast of California. Call density trends are compared between the monitoring sites and at the same monitoring site over time. Call densities also are compared to several natural and human-influenced variables including season, time of day, lunar illumination, and ocean noise. The results reveal substantial differences in call densities

  19. Acoustic Energy: An Innovative Technology for Stimulating Oil Wells

    SciTech Connect

    Edgar, Dorland E.; Peters, Robert W.; Johnson, Donald O.; Paulsen, P. David; Roberts, Wayne

    2006-04-30

    The objective of this investigation was to demonstrate the effectiveness of sonication in reducing the viscosity of heavy crude oils. Sonication is the use of acoustic or sound energy to produce physical and/or chemical changes in materials, usually fluids. The goal of the first project phase was to demonstrate a proof of concept for the project objective. Batch tests of three commercially available, single-weight oils (30-, 90-, and 120-wt) were performed in the laboratory. Several observations and conclusions were made from this series of experiments. These include the following: (1) In general, the lower the acoustic frequency, the greater the efficiency in reducing the viscosity of the oils; (2) Sonication treatment of the three oils resulted in reductions in viscosity that ranged from a low of 31% to a high of 75%; and (3) The results of the first phase of the project successfully demonstrated that sonication could reduce the viscosity of oils of differing viscosity. The goal of the second project phase was to demonstrate the ability of sonication to reduce the viscosity of three crude oils ranging from a light crude to a heavy crude. The experiments also were designed to examine the benefits of two proprietary chemical additives used in conjunction with sonication. Acoustic frequencies ranging from 800 Hz to 1.6 kHz were used in these tests, and a reactor chamber was designed for flow-through operation with a capacity of one gallon (3.8 liters). The three crude oils selected for use in the testing program were: (1) a heavy crude from California with a viscosity of approximately 65,000 cP (API gravity about 12{sup o}), (2) a crude from Alabama with a significant water content and a viscosity of approximately 6,000 cP (API gravity about 22 {sup o}), and (3) a light crude from the Middle East with a viscosity of approximately 700 cP (API gravity about 32{sup o}). The principal conclusions derived from the second project phase include the following: (1) The

  20. Acoustic planar hyperlens based on anisotropic density-near-zero metamaterials

    SciTech Connect

    Gu, Yuan; Cheng, Ying Liu, Xiaojun

    2015-09-28

    Based on anisotropic density-near-zero metamaterials, we demonstrate a planar hyperlens with resolution beyond the diffraction limit in both one and two lateral dimensions. In contrast to the cylindrical hyperlens with elliptical dispersions of finite anisotropy, the proposed planar hyperlens is designed with flat near-zero dispersion that supports wave tunneling with extremely high phase velocity for infinite large transverse wave vectors. Therefore, the acoustic evanescent waves immediately concentrate into the designed oblique path till the output surface, leading to a subwavelength resolution. Prototype hyperlens is constructed with a membrane-network by means of equivalent lumped-circuit model, and the subwavelength magnifying performance for a pair of one-dimensional line objects as well as the complex two-dimensional structure is demonstrated. This method provides diverse routes to construct hyperlens operating without the limitation on imaging region in practical applications.

  1. Energy Transform and Initial Acoustic Pressure Distribution in Microwave-induced Thermoacoustic Tomography.

    PubMed

    Yan, Jing; Tao, Chunjing; Wu, Shizeng

    2005-01-01

    A study of Microwave-induced Thermoacoustic Tomography is presented in this paper. Microwaves illuminate biological tissues to generate acoustic waves by thermoelastic expansion when electromagnetic energy was absorbed by human tissues. The generated acoustic waves carry information about different electromagnetic properties of different tissues which will be collected and processed to reconstruct human cross section image. In this paper, digital electromagnetic human body model with 1cm resolution was founded according to algorithm requirements. Firstly we analyzed the transform and interrelation among electromagnetic energy, heat energy and acoustic energy. On the basis of established human model: (1) we calculated initial acoustic pressure distribution in cross section image under plane microwave radiation with different frequency. It shows that microwave absorption properties and initial acoustic pressure were different with the change of frequency; (2) using single pulse to illuminate human model, initial acoustic pressure maps of thorax cross section at different time steps were analyzed. These results provided a research basis for further study and calculation of acoustic pressure in microwave-induced thermoacoustic tomography.

  2. Reverberant acoustic energy in auditoria that comprise systems of coupled rooms

    NASA Astrophysics Data System (ADS)

    Summers, Jason Erik

    A frequency-dependent model for levels and decay rates of reverberant energy in systems of coupled rooms is developed and compared with measurements conducted in a 1:10 scale model and in Bass Hall, Fort Worth, TX. Schroeder frequencies of subrooms, fSch, characteristic size of coupling apertures, a, relative to wavelength lambda, and characteristic size of room surfaces, l, relative to lambda define the frequency regions. At high frequencies [HF (f >> f Sch, a >> lambda, l >> lambda)], this work improves upon prior statistical-acoustics (SA) coupled-ODE models by incorporating geometrical-acoustics (GA) corrections for the model of decay within subrooms and the model of energy transfer between subrooms. Previous researchers developed prediction algorithms based on computational GA. Comparisons of predictions derived from beam-axis tracing with scale-model measurements indicate that systematic errors for coupled rooms result from earlier tail-correction procedures that assume constant quadratic growth of reflection density. A new algorithm is developed that uses ray tracing rather than tail correction in the late part and is shown to correct this error. At midfrequencies [MF (f >> f Sch, a ˜ lambda)], HF models are modified to account for wave effects at coupling apertures by including analytically or heuristically derived power transmission coefficients tau. This work improves upon prior SA models of this type by developing more accurate estimates of random-incidence tau. While the accuracy of the MF models is difficult to verify, scale-model measurements evidence the expected behavior. The Biot-Tolstoy-Medwin-Svensson (BTMS) time-domain edge-diffraction model is newly adapted to study transmission through apertures. Multiple-order BTMS scattering is theoretically and experimentally shown to be inaccurate due to the neglect of slope diffraction. At low frequencies (f ˜ f Sch), scale-model measurements have been qualitatively explained by application of

  3. COMBINATION OF DENSITY AND ENERGY MODULATION IN MICROBUNCHING ANALYSIS

    SciTech Connect

    Tsai, Cheng Ying; Li, Rui

    2016-05-01

    Microbunching instability (MBI) has been one of the most challenging issues in the transport of high-brightness electron beams for modern recirculating or energy recovery linac machines. Recently we have developed and implemented a Vlasov solver [1] to calculate the microbunching gain for an arbitrary beamline lattice, based on the extension of existing theoretical formulation [2-4] for the microbunching amplification from an initial density perturbation to the final density modulation. For more thorough analyses, in addition to the case of (initial) density to (final) density amplification, we extend in this paper the previous formulation to more general cases, including energy to density, density to energy and energy to energy amplifications for a recirculation machine. Such semi-analytical formulae are then incorporated into our Vlasov solver, and qualitative agreement is obtained when the semi-analytical Vlasov results are compared with particle tracking simulation using ELEGANT [5].

  4. Acoustic detection of high energy neutrinos in sea water: status and prospects

    NASA Astrophysics Data System (ADS)

    Lahmann, Robert

    2017-03-01

    The acoustic neutrino detection technique is a promising approach for future large-scale detectors with the aim of measuring the small expected flux of neutrinos at energies in the EeV-range and above. The technique is based on the thermo-acoustic model, which implies that the energy deposition by a particle cascade - resulting from a neutrino interaction in a medium with suitable thermal and acoustic properties - leads to a local heating and a subsequent characteristic pressure pulse that propagates in the surrounding medium. Current or recent test setups for acoustic neutrino detection have either been add-ons to optical neutrino telescopes or have been using acoustic arrays built for other purposes, typically for military use. While these arrays have been too small to derive competitive limits on neutrino fluxes, they allowed for detailed studies of the experimental technique. With the advent of the research infrastructure KM3NeT in the Mediterranean Sea, new possibilities will arise for acoustic neutrino detection. In this article, results from the "first generation" of acoustic arrays will be summarized and implications for the future of acoustic neutrino detection will be discussed.

  5. Distinguishing interacting dark energy from wCDM with CMB, lensing, and baryon acoustic oscillation data

    SciTech Connect

    Väliviita, Jussi; Palmgren, Elina E-mail: elina.palmgren@helsinki.fi

    2015-07-01

    We employ the Planck 2013 CMB temperature anisotropy and lensing data, and baryon acoustic oscillation (BAO) data to constrain a phenomenological wCDM model, where dark matter and dark energy interact. We assume time-dependent equation of state parameter for dark energy, and treat dark matter and dark energy as fluids whose energy-exchange rate is proportional to the dark-matter density. The CMB data alone leave a strong degeneracy between the interaction rate and the physical CDM density parameter today, ω{sub c}, allowing a large interaction rate |Γ| ∼ H{sub 0}. However, as has been known for a while, the BAO data break this degeneracy. Moreover, we exploit the CMB lensing potential likelihood, which probes the matter perturbations at redshift z ∼ 2 and is very sensitive to the growth of structure, and hence one of the tools for discerning between the ΛCDM model and its alternatives. However, we find that in the non-phantom models (w{sub de}>−1), the constraints remain unchanged by the inclusion of the lensing data and consistent with zero interaction, −0.14 < Γ/H{sub 0} < 0.02 at 95% CL. On the contrary, in the phantom models (w{sub de}<−1), energy transfer from dark energy to dark matter is moderately favoured over the non-interacting model; 0−0.57 < Γ/H{sub 0} < −0.1 at 95% CL with CMB+BAO, while addition of the lensing data shifts this to −0.46 < Γ/H{sub 0} < −0.01.

  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. Effect of static pressure on acoustic energy radiated by cavitation bubbles in viscous liquids under ultrasound.

    PubMed

    Yasui, Kyuichi; Towata, Atsuya; Tuziuti, Toru; Kozuka, Teruyuki; Kato, Kazumi

    2011-11-01

    The effect of static pressure on acoustic emissions including shock-wave emissions from cavitation bubbles in viscous liquids under ultrasound has been studied by numerical simulations in order to investigate the effect of static pressure on dispersion of nano-particles in liquids by ultrasound. The results of the numerical simulations for bubbles of 5 μm in equilibrium radius at 20 kHz have indicated that the optimal static pressure which maximizes the energy of acoustic waves radiated by a bubble per acoustic cycle increases as the acoustic pressure amplitude increases or the viscosity of the solution decreases. It qualitatively agrees with the experimental results by Sauter et al. [Ultrason. Sonochem. 15, 517 (2008)]. In liquids with relatively high viscosity (∼200 mPa s), a bubble collapses more violently than in pure water when the acoustic pressure amplitude is relatively large (∼20 bar). In a mixture of bubbles of different equilibrium radius (3 and 5 μm), the acoustic energy radiated by a 5 μm bubble is much larger than that by a 3 μm bubble due to the interaction with bubbles of different equilibrium radius. The acoustic energy radiated by a 5 μm bubble is substantially increased by the interaction with 3 μm bubbles.

  8. 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...

  9. Relation Between the Dark Energy Density and Temperature

    NASA Astrophysics Data System (ADS)

    Saadat, H.

    2011-01-01

    In this article we investigate the relation between the temperature and density of the dark energy. We find that the temperature of the dark universe is proportional to the inverse of dark energy density. Also we discuss some values of the important parameters of the theory.

  10. Equation of state for titanium at high energy densities

    NASA Astrophysics Data System (ADS)

    Khishchenko, K. V.

    2016-11-01

    A caloric equation-of-state model, which represents the relation of pressure with density and internal energy, is applied for titanium in the bcc and liquid phases. Thermodynamic characteristics along the cold-compression curve at T = 0 and Hugoniots are calculated for the metal and compared with available data from shock-wave experiments at high energy densities.

  11. Theoretical Estimation of the Acoustic Energy Generation and Absorption Caused by Jet Oscillation

    NASA Astrophysics Data System (ADS)

    Takahashi, Kin'ya; Iwagami, Sho; Kobayashi, Taizo; Takami, Toshiya

    2016-04-01

    We investigate the energy transfer between the fluid field and acoustic field caused by a jet driven by an acoustic particle velocity field across it, which is the key to understanding the aerodynamic sound generation of flue instruments, such as the recorder, flute, and organ pipe. Howe's energy corollary allows us to estimate the energy transfer between these two fields. For simplicity, we consider the situation such that a free jet is driven by a uniform acoustic particle velocity field across it. We improve the semi-empirical model of the oscillating jet, i.e., exponentially growing jet model, which has been studied in the field of musical acoustics, and introduce a polynomially growing jet model so as to apply Howe's formula to it. It is found that the relative phase between the acoustic oscillation and jet oscillation, which changes with the distance from the flue exit, determines the quantity of the energy transfer between the two fields. The acoustic energy is mainly generated in the downstream area, but it is consumed in the upstream area near the flue exit in driving the jet. This theoretical examination well explains the numerical calculation of Howe's formula for the two-dimensional flue instrument model in our previous work [http://doi.org/10.1088/0169-5983/46/6/061411, Fluid Dyn. Res. 46, 061411 (2014)] as well as the experimental result of Yoshikawa et al. [http://doi.org/10.1016/j.jsv.2012.01.026, J. Sound Vib. 331, 2558 (2012)].

  12. Modeling and design of two-dimensional membrane-type active acoustic metamaterials with tunable anisotropic density.

    PubMed

    Allam, Ahmed; Elsabbagh, Adel; Akl, Wael

    2016-11-01

    A two-dimensional active acoustic metamaterial with controllable anisotropic density is introduced. The material consists of composite lead-lead zirconate titanate plates clamped to an aluminum structure with air as the background fluid. The effective anisotropic density of the material is controlled, independently for two orthogonal directions, by means of an external static electric voltage signal. The material is used in the construction of a reconfigurable waveguide capable of controlling the direction of the acoustic waves propagating through it. An analytic model based on the acoustic two-port theory, the theory of piezoelectricity, the laminated pre-stressed plate theory, and the S-parameters retrieval method is developed to predict the behavior of the material. The results are verified using the finite element method. Excellent agreement is found between both models for the studied frequency and voltage ranges. The results show that, below 1600 Hz, the density is controllable within orders of magnitude relative to the uncontrolled case. The results also suggest that simple controllers could be used to program the material density toward full control of the directivity and dispersion characteristics of acoustic waves.

  13. 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.

  14. Transmission of wave energy in curved ducts. [acoustic propagation within rigid walls

    NASA Technical Reports Server (NTRS)

    Rostafinski, W.

    1974-01-01

    Investigation of the ability of circular bends to transmit acoustic energy flux. A formulation of wave-energy flow is developed for motion in curved ducts. A parametric study over a range of frequencies shows the ability of circular bends to transmit energy in the case of perfectly rigid walls.

  15. Device and method for generating a beam of acoustic energy from a borehole, and applications thereof

    DOEpatents

    Vu, Cung Khac; Sinha, Dipen N; Pantea, Cristian; Nihei, Kurt T; Schmitt, Denis P; Skelt, Christopher

    2013-10-01

    In some aspects of the invention, a method of generating a beam of acoustic energy in a borehole is disclosed. The method includes generating a first broad-band acoustic pulse at a first broad-band frequency range having a first central frequency and a first bandwidth spread; generating a second broad-band acoustic pulse at a second broad-band frequency range different than the first frequency range having a second central frequency and a second bandwidth spread, wherein the first acoustic pulse and second acoustic pulse are generated by at least one transducer arranged on a tool located within the borehole; and transmitting the first and the second broad-band acoustic pulses into an acoustically non-linear medium, wherein the composition of the non-linear medium produces a collimated pulse by a non-linear mixing of the first and second acoustic pulses, wherein the collimated pulse has a frequency equal to the difference in frequencies between the first central frequency and the second central frequency and a bandwidth spread equal to the sum of the first bandwidth spread and the second bandwidth spread.

  16. High-Q cross-plate phononic crystal resonator for enhanced acoustic wave localization and energy harvesting

    NASA Astrophysics Data System (ADS)

    Yang, Aichao; Li, Ping; Wen, Yumei; Yang, Chao; Wang, Decai; Zhang, Feng; Zhang, Jiajia

    2015-05-01

    A high-Q cross-plate phononic crystal resonator (Cr-PCR) coupled with an electromechanical Helmholtz resonator (EMHR) is proposed to improve acoustic wave localization and energy harvesting. Owing to the strongly directional wave-scattering effect of the cross-plate corners, strong confinement of acoustic waves emerges. Consequently, the proposed Cr-PCR structure exhibits ∼353.5 times higher Q value and ∼6.1 times greater maximum pressure amplification than the phononic crystal resonator (Cy-PCR) (consisting of cylindrical scatterers) of the same size. Furthermore, the harvester using the proposed Cr-PCR and the EMHR has ∼22 times greater maximum output-power volume density than the previous harvester using Cy-PCR and EMHR structures.

  17. Dynamical energy analysis for built-up acoustic systems at high frequencies.

    PubMed

    Chappell, D J; Giani, S; Tanner, G

    2011-09-01

    Standard methods for describing the intensity distribution of mechanical and acoustic wave fields in the high frequency asymptotic limit are often based on flow transport equations. Common techniques are statistical energy analysis, employed mostly in the context of vibro-acoustics, and ray tracing, a popular tool in architectural acoustics. Dynamical energy analysis makes it possible to interpolate between standard statistical energy analysis and full ray tracing, containing both of these methods as limiting cases. In this work a version of dynamical energy analysis based on a Chebyshev basis expansion of the Perron-Frobenius operator governing the ray dynamics is introduced. It is shown that the technique can efficiently deal with multi-component systems overcoming typical geometrical limitations present in statistical energy analysis. Results are compared with state-of-the-art hp-adaptive discontinuous Galerkin finite element simulations.

  18. ACOUSTIC RECTIFICATION IN DISPERSIVE MEDIA

    SciTech Connect

    Cantrell, John H.

    2009-03-03

    It is shown that the shapes of acoustic radiation-induced static strain and displacement pulses (rectified acoustic pulses) are defined locally by the energy density of the generating waveform. Dispersive properties are introduced analytically by assuming that the rectified pulses are functionally dependent on a phase factor that includes both dispersive and nonlinear terms. The dispersion causes an evolutionary change in the shape of the energy density profile that leads to the generation of solitons experimentally observed in fused silica.

  19. 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.

  20. Resource Evaluation and Energy Production Estimate for a Tidal Energy Conversion Installation using Acoustic Flow Measurements

    NASA Astrophysics Data System (ADS)

    Gagnon, Ian; Baldwin, Ken; Wosnik, Martin

    2015-11-01

    The ``Living Bridge'' project plans to install a tidal turbine at Memorial Bridge in the Piscataqua River at Portsmouth, NH. A spatio-temporal tidal energy resource assessment was performed using long term bottom-deployed Acoustic Doppler Current Profilers ADCP. Two locations were evaluated: at the planned deployment location and mid-channel. The goal was to determine the amount of available kinetic energy that can be converted into usable electrical energy on the bridge. Changes in available kinetic energy with ebb/flood and spring/neap tidal cycles and electrical energy demand were analyzed. A system model is used to calculate the net energy savings using various tidal generator and battery bank configurations. Differences in the tidal characteristics between the two measurement locations are highlighted. Different resource evaluation methodologies were also analyzed, e.g., using a representative ADCP ``bin'' vs. a more refined, turbine-geometry-specific methodology, and using static bin height vs. bin height that move w.r.t. the free surface throughout a tidal cycle (representative of a bottom-fixed or floating turbine deployment, respectively). ADCP operating frequencies and bin sizes affect the standard deviation of measurements, and measurement uncertainties are evaluated. Supported by NSF-IIP grant 1430260.

  1. Energy density of relic gravity waves from inflation

    SciTech Connect

    Sahni, V. )

    1990-07-15

    We evaluate both the spectral energy density and the total energy density for relic gravity waves produced during the transition from an early inflationary phase to a matter-dominated Friedmann-Robertson-Walker-type expansion: {ital a}{similar to}{ital t}{sup {ital c}} ({ital c}{lt}1). We find that for power-law inflation the spectral energy density for gravity waves has more power on larger scales than for purely exponential inflation. Evaluating the energy density of created massless particles (both gravitons and massless scalars) we find that in the case of exponential inflation the ratio of the density of created particles to the total density of matter is a constant, if {ital c}{ge}1/2. This unusual behavior is a consequence of the fact that the equation of state for created particles mimics the equation of state for matter driving the expansion of the Universe. As a result, self-consistent solutions of the Einstein equations can be found, in which the expansion of the Universe is sustained solely by the ongoing production of massless particles, so that {ital G}{sub {mu}{nu}}=8{pi}{ital G}{l angle}{ital T}{sub {mu}{nu}}{r angle}. In the case of power-law and quasiexponential inflation we find that the ratio of the energy density of gravity waves to the background matter density increases with time, as gravity waves with longer wavelengths and larger amplitudes enter the horizon at successively later epochs. This could lead to the energy density of gravity waves becoming comparable to the energy density of matter at late times, if inflation commenced at Planckian energies.

  2. 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.

  3. 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.

  4. Development of critical surface diagnostic based on the ion acoustic decay instability in laser produced high density plasma

    SciTech Connect

    Mizuno, K.; DeGroot, J.S.; Drake, R.P.; Seka, W.; Craxton, R.S.; Estabrook, K.G.

    1994-12-31

    We have developed a large angle, UV collective Thomson scattering (CTS) diagnostic for high density, hot plasma relevant to laser fusion. The CTS measured the basic parameters of the plasma waves (frequency, wave number), or the spectral density function for selected wave vectors of plasma waves, which were excited by the IADI (ion acoustic parametric decay instability). It is a good diagnostic tool for a local electron temperature measurement. The electron temperature was estimated by measuring either ion acoustic wave or electron plasma wave in the laser intensity window of 1density plasma.

  5. Accounting for delay of energy transfer between coupled rooms in statistical-acoustics models of reverberant-energy decay.

    PubMed

    Summers, Jason E

    2012-08-01

    A statistical-acoustics model for energy decay in systems of two or more coupled rooms is introduced, which accounts for the distribution of delay in the transfer of energy between subrooms that results from the finite speed of sound. The method extends previous models based on systems of coupled ordinary differential equations by using functional differential equations to explicitly model dependence on prior values of energy in adjacent subrooms. Predictions of the model are illustrated for a two-room coupled system and compared with the predictions of a benchmark computational geometrical-acoustics model.

  6. Energy Source Study Technical Report for Deployable Acoustic Projector System (DAPS)

    DTIC Science & Technology

    1988-12-23

    S SPARTON"- AD-A278 879 7097-0001-1192 ENERGY SOURCE STUDY TECHNICAL REPORT FOR DEPLOYABLE ACOUSTIC PROJECTOR SYSTEM (DAPS) Contract N62190-88-M...SUBTITLE 5. FUNDING NUMBERS Energy Source Study Technical Report for Deployable C:N62190-88-q+0755 Acoustic Projector System (DAPS) 6. AUTHOR(S) 7...Rev 2-89) P~IýAIppd by ill* 164 it- IJs IL- 3 Fst’ rPAITON OWiENSE mac vrroNcS r 7097-0001-1192 ENERGY SOURCE STUDY TECHNICAL REPORT I FOR DEPLOYABLE

  7. Energy loss to intravalley acoustic modes in nano-dimensional wire structures at low temperatures

    NASA Astrophysics Data System (ADS)

    Nag, S.; Das, B.; Basu, A.; Das, J.; Bhattacharya, D. P.; Sarkar, C. K.

    2017-03-01

    The theory of rate of loss of energy of non-equilibrium electrons due to inelastic interaction with the intravalley acoustic phonons in a nano-dimensional semiconductor wire has been developed under the condition of low lattice temperature, when the approximations of the well known traditional theory are not valid. Numerical results are obtained for narrow-channel GaAs-GaAlAs wires structures. On comparison with other available results it is revealed that the finite energy of the intravalley acoustic phonons and, the use of the full form of the phonon distribution without truncation to the equipartition law, produce significant changes in the energy loss characteristics at low temperatures.

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

    PubMed Central

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

    2014-01-01

    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. PMID:25086548

  9. 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.

  10. Neurotrophin-3 regulates ribbon synapse density in the cochlea and induces synapse regeneration after acoustic trauma

    PubMed Central

    Wan, Guoqiang; Gómez-Casati, Maria E; Gigliello, Angelica R; Liberman, M Charles; Corfas, Gabriel

    2014-01-01

    Neurotrophin-3 (Ntf3) and brain derived neurotrophic factor (Bdnf) are critical for sensory neuron survival and establishment of neuronal projections to sensory epithelia in the embryonic inner ear, but their postnatal functions remain poorly understood. Using cell-specific inducible gene recombination in mice we found that, in the postnatal inner ear, Bbnf and Ntf3 are required for the formation and maintenance of hair cell ribbon synapses in the vestibular and cochlear epithelia, respectively. We also show that supporting cells in these epithelia are the key endogenous source of the neurotrophins. Using a new hair cell CreERT line with mosaic expression, we also found that Ntf3's effect on cochlear synaptogenesis is highly localized. Moreover, supporting cell-derived Ntf3, but not Bbnf, promoted recovery of cochlear function and ribbon synapse regeneration after acoustic trauma. These results indicate that glial-derived neurotrophins play critical roles in inner ear synapse density and synaptic regeneration after injury. DOI: http://dx.doi.org/10.7554/eLife.03564.001 PMID:25329343

  11. Ultrasound tomography for simultaneous reconstruction of acoustic density, attenuation, and compressibility profiles.

    PubMed

    Mojabi, Pedram; LoVetri, Joe

    2015-04-01

    A fast and efficient forward scattering solver is developed for use in ultrasound tomography. The solver is formulated so as to enable the calculation of scattering from large and relatively high-contrast objects with inhomogeneous physical properties that vary simultaneously in acoustic attenuation, compressibility, and density. It is based on the method of moments in conjunction with a novel implementation of the conjugate gradient algorithm which requires the use of the adjoints of the scattering operators. The solver takes advantage of the symmetric block Toeplitz matrix with symmetric Toeplitz blocks property of the Green's function matrix to increase efficiency and only stores the first row of this matrix to reduce memory requirements. This row is then used for the matrix-vector multiplication using the fast Fourier transform technique, thus, resulting in the computational complexity of O(n log n). The marching-on-source technique is also used to provide a good initial guess which allows the conjugate gradient technique to converge faster than initializing with an arbitrary guess. This feature is important in tomographic inversion algorithms which require that the object to be imaged be interrogated via several incident fields. Forward scattering and inversion examples, based on the Conjugate Gradient Least Squares regularized Born Iterative Method, are shown, in two-dimensions, for objects varying in all three physical properties.

  12. Efficient Structure Resonance Energy Transfer from Microwaves to Confined Acoustic Vibrations in Viruses

    PubMed Central

    Yang, Szu-Chi; Lin, Huan-Chun; Liu, Tzu-Ming; Lu, Jen-Tang; Hung, Wan-Ting; Huang, Yu-Ru; Tsai, Yi-Chun; Kao, Chuan-Liang; Chen, Shih-Yuan; Sun, Chi-Kuang

    2015-01-01

    Virus is known to resonate in the confined-acoustic dipolar mode with microwave of the same frequency. However this effect was not considered in previous virus-microwave interaction studies and microwave-based virus epidemic prevention. Here we show that this structure-resonant energy transfer effect from microwaves to virus can be efficient enough so that airborne virus was inactivated with reasonable microwave power density safe for the open public. We demonstrate this effect by measuring the residual viral infectivity of influenza A virus after illuminating microwaves with different frequencies and powers. We also established a theoretical model to estimate the microwaves power threshold for virus inactivation and good agreement with experiments was obtained. Such structure-resonant energy transfer induced inactivation is mainly through physically fracturing the virus structure, which was confirmed by real-time reverse transcription polymerase chain reaction. These results provide a pathway toward establishing a new epidemic prevention strategy in open public for airborne virus. PMID:26647655

  13. Simulation and analysis chain for acoustic ultra-high energy neutrino detectors in water

    NASA Astrophysics Data System (ADS)

    Neff, M.; Anton, G.; Enzenhöfer, A.; Graf, K.; Hößl, J.; Katz, U.; Lahmann, R.; Sieger, C.

    2013-05-01

    Acoustic neutrino detection is a promising approach for large-scale ultra-high energy neutrino detectors in water. In this article, a Monte Carlo simulation chain for acoustic neutrino detection devices in water will be presented. The simulation chain covers the generation of the acoustic pulse produced by a neutrino interaction and its propagation to the sensors within the detector. Currently, ambient and transient noise models for the Mediterranean Sea and simulations of the data acquisition hardware, equivalent to the one used in ANTARES/AMADEUS, are implemented. A pre-selection scheme for neutrino-like signals based on matched filtering is employed, as it is used for on-line filtering. To simulate the whole processing chain for experimental data, signal classification and acoustic source reconstruction algorithms are integrated in an analysis chain. An overview of design and capabilities of the simulation and analysis chain will be presented and preliminary studies will be discussed.

  14. [Physiological-occupational assessment of acoustic load with equal energy but different time and informational characteristics].

    PubMed

    Suvorov, G A; Shkarinov, L N; Kravchenko, O K; Kur'erov, N N

    1999-01-01

    The article deals with results of experimental study comparing effects of 4 types of acoustic load--noise (constant and impulse) and music (electronic symphonic one and rap)--on hearing sensitivity, processes in nervous system and subjective evaluation. All types of acoustic load were equal in energy (on evaluation according to equivalent level during the experiment). The study included 2 levels of load--90 and 95 dB. The differences revealed demonstrate importance of impulse parameters of noise and musical load for reactions of acoustic analyzer and central nervous system. The experiments show that evaluation of harm caused by temporary and impulse noises should be based not only on assessment of specific (hearing) function, but also on parameters of central nervous system state. The authors found that music of certain acoustic and informational parameters may harm hearing function.

  15. Fifth International Workshop on Detection, Classification, Localization and Density Estimation of Marine Mammals using Passive Acoustics

    DTIC Science & Technology

    2013-09-30

    spring 2011 in Seattle) • The Fourth International Conference on Detection and Classification of Marine Mammals using Passive Acoustics ( Pavia ...Italy, 2009) • The International BioAcoustic Congress ( Pavia , Italy, 2009) Report Documentation Page Form ApprovedOMB No. 0704-0188 Public reporting

  16. 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.

  17. Thermospheric Density Model Including High-Latitude Energy Sources

    NASA Astrophysics Data System (ADS)

    Moe, O. K.; Moe, M. M.

    2006-12-01

    As was predicted long ago by Sydney Chapman, there is a major contribution to thermospheric energy from the magnetosphere at all times. The contribution of this magnetospheric energy source produces a neutral density bulge at high latitudes even during geomagnetically quiet times. We present an analytical, semi- empirical model of the global neutral density at such quiet times. The total density is expressed as the sum of two terms: The first term describes the combined effects of the solar ultra-violet heating and various other contributions like the semi-annual variation; the second term gives the contribution to the density associated with particle precipitation and joule heating coming from magnetospheric sources during times of low geomagnetic activity. The region of density enhancement at high latitudes is associated with the locations of the dayside cusps. Therefore the model produces a density distribution which depends on universal time as well as on altitude, latitude, local time, and the usual solar UV energy source. The numerical values of the parameters in the empirical model were originally determined 30 years ago from density data collected by the Bell-MESA accelerometer on the LOGACS satellite and the pressure gauge on the SPADES satellite. As an example of the model output, we show a Mercator projection of the global density distribution at 400 km altitude at 12 hours GMT in late May at a time of moderate solar activity and low geomagnetic activity. The parameters in the model can now be substantially improved by using recent advances like the latest description of the semi-annual variation and by incorporating the precise density measurements made by the accelerometers on board the CHAMP and GRACE satellites. In the original model, density values at times of high geomagnetic activity were included in the second density term. The parameters in that term can also be improved as accurate storm-time densities become available.

  18. Deployable Acoustic Projector System (DAPS) Energy Source Study

    DTIC Science & Technology

    1988-12-01

    final, etc. If Statements on Technical applicable, enter inclusive report dates (e.g. 10 Documents. Jun 87 - 30 Jun 88). DOE - See authorities...aJIUILOI NG 20C WIII OCSR L[~,CONNETICUT 0 811 LT = LECT I -w L94 5 06 036 Form Appmv’ovd REPORT DOCUMENTATION PAGE C No. 0A,-0pov pull efa’, m a fm thi...ONLY (Leave blank) 2. REPORT DATE 3. REPORT TYPE AND DATES COVERED Dec 88 Final 4. TITLE AND SUBTITLE S. FUNDING NUMBERS Deployable Acoustic Projector

  19. High energy density nanocomposite capacitors using non-ferroelectric nanowires

    NASA Astrophysics Data System (ADS)

    Tang, Haixiong; Sodano, Henry A.

    2013-02-01

    A high energy density nanocomposite capacitor is fabricated by incorporating high aspect ratio functionalized TiO2 nanowires (NWs) into a polyvinylidene-fluoride matrix. These nanocomposites exhibited energy density as high as 12.4 J/cc at 450 MV/m, which is nine times larger than commercial biaxially oriented polypropylene polypropylene capacitors (1.2 J/cc at 640 MV/m). Also, the power density can reach 1.77 MW/cc with a discharge speed of 2.89 μs. The results presented here demonstrate that nanowires can be used to develop nanocomposite capacitors with high energy density and fast discharge speed for future pulsed-power applications.

  20. Decoding Group Vocalizations: The Acoustic Energy Distribution of Chorus Howls Is Useful to Determine Wolf Reproduction

    PubMed Central

    López-Bao, José Vicente; Llaneza, Luis; Fernández, Carlos; Font, Enrique

    2016-01-01

    Population monitoring is crucial for wildlife management and conservation. In the last few decades, wildlife researchers have increasingly applied bioacoustics tools to obtain information on several essential ecological parameters, such as distribution and abundance. One such application involves wolves (Canis lupus). These canids respond to simulated howls by emitting group vocalizations known as chorus howls. These responses to simulated howls reveal the presence of wolf litters during the breeding period and are therefore often used to determine the status of wolf populations. However, the acoustic structure of chorus howls is complex and discriminating the presence of pups in a chorus is sometimes difficult, even for experienced observers. In this study, we evaluate the usefulness of analyses of the acoustic energy distribution in chorus howls to identify the presence of pups in a chorus. We analysed 110 Iberian wolf chorus howls with known pack composition and found that the acoustic energy distribution is concentrated at higher frequencies when there are pups vocalizing. We built predictive models using acoustic energy distribution features to determine the presence of pups in a chorus, concluding that the acoustic energy distribution in chorus howls can be used to determine the presence of wolf pups in a pack. The method we outline here is objective, accurate, easily implemented, and independent of the observer's experience. These advantages are especially relevant in the case of broad scale surveys or when many observers are involved. Furthermore, the analysis of the acoustic energy distribution can be implemented for monitoring other social canids that emit chorus howls such as jackals or coyotes, provides an easy way to obtain information on ecological parameters such as reproductive success, and could be useful to study other group vocalizations. PMID:27144887

  1. Decoding Group Vocalizations: The Acoustic Energy Distribution of Chorus Howls Is Useful to Determine Wolf Reproduction.

    PubMed

    Palacios, Vicente; López-Bao, José Vicente; Llaneza, Luis; Fernández, Carlos; Font, Enrique

    2016-01-01

    Population monitoring is crucial for wildlife management and conservation. In the last few decades, wildlife researchers have increasingly applied bioacoustics tools to obtain information on several essential ecological parameters, such as distribution and abundance. One such application involves wolves (Canis lupus). These canids respond to simulated howls by emitting group vocalizations known as chorus howls. These responses to simulated howls reveal the presence of wolf litters during the breeding period and are therefore often used to determine the status of wolf populations. However, the acoustic structure of chorus howls is complex and discriminating the presence of pups in a chorus is sometimes difficult, even for experienced observers. In this study, we evaluate the usefulness of analyses of the acoustic energy distribution in chorus howls to identify the presence of pups in a chorus. We analysed 110 Iberian wolf chorus howls with known pack composition and found that the acoustic energy distribution is concentrated at higher frequencies when there are pups vocalizing. We built predictive models using acoustic energy distribution features to determine the presence of pups in a chorus, concluding that the acoustic energy distribution in chorus howls can be used to determine the presence of wolf pups in a pack. The method we outline here is objective, accurate, easily implemented, and independent of the observer's experience. These advantages are especially relevant in the case of broad scale surveys or when many observers are involved. Furthermore, the analysis of the acoustic energy distribution can be implemented for monitoring other social canids that emit chorus howls such as jackals or coyotes, provides an easy way to obtain information on ecological parameters such as reproductive success, and could be useful to study other group vocalizations.

  2. A high energy density relaxor antiferroelectric pulsed capacitor dielectric

    SciTech Connect

    Jo, Hwan Ryul; Lynch, Christopher S.

    2016-01-14

    Pulsed capacitors require high energy density and low loss, properties that can be realized through selection of composition. Ceramic (Pb{sub 0.88}La{sub 0.08})(Zr{sub 0.91}Ti{sub 0.09})O{sub 3} was found to be an ideal candidate. La{sup 3+} doping and excess PbO were used to produce relaxor antiferroelectric behavior with slim and slanted hysteresis loops to reduce the dielectric hysteresis loss, to increase the dielectric strength, and to increase the discharge energy density. The discharge energy density of this composition was found to be 3.04 J/cm{sup 3} with applied electric field of 170 kV/cm, and the energy efficiency, defined as the ratio of the discharge energy density to the charging energy density, was 0.920. This high efficiency reduces the heat generated under cyclic loading and improves the reliability. The properties were observed to degrade some with temperature increase above 80 °C. Repeated electric field cycles up to 10 000 cycles were applied to the specimen with no observed performance degradation.

  3. 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

  4. Contributed Review: Recent developments in acoustic energy harvesting for autonomous wireless sensor nodes applications.

    PubMed

    Khan, Farid Ullah; Khattak, Muhammad Umair

    2016-02-01

    Rapid developments in micro electronics, micro fabrication, ultra-large scale of integration, ultra-low power sensors, and wireless technology have greatly reduced the power consumption requirements of wireless sensor nodes (WSNs) and make it possible to operate these devices with energy harvesters. Likewise, other energy harvesters, acoustic energy harvesters (AEHs), have been developed and are gaining swift interest in last few years. This paper presents a review of AEHs reported in the literature for the applications of WSNs. Based on transduction mechanism, there are two types of AEHs: piezoelectric acoustic energy harvesters (PEAEHs) and electromagnetic acoustic energy harvesters (EMAEHs). The reported AEHs are mostly characterized under the sound pressure level (SPL) that ranges from 45 to 161 dB. The range for resonant frequency of the produced AEHs is from 146 Hz to 24 kHz and these produced 0.68 × 10(-6) μW to 30 mW power. The maximum power (30 mW) is produced by a PEAEH, when the harvester is subjected to a SPL of 161 dB and 2.64 kHz frequency. However, for EMAEHs, the maximum power reported is about 1.96 mW (at 125 dB and 143 Hz). Under the comparable SPLs, the power production by the reported EMAEHs is relatively better than that of PEAEHs, moreover, due to lower resonant frequency, the EMAEHs are more feasible for the low frequency band acoustical environment.

  5. Acoustic study of a linear low-density polyethylene film after modification of the crystalline structure by heating.

    PubMed

    Tohmyoh, Hironori; Sakamoto, Yuhei

    2014-02-01

    We report on a hybrid microscopy technique that enables us to measure the acoustic properties of a thin polymer film together with an optical microscope image of the corresponding area. Linear low-density polyethylene films are heated to various temperatures and examined by the technique. Density of the film is increased by heating and its sound velocity is decreased compared with a film without heating. Also, spherulites can clearly be seen in the optical microscope image, supporting the thermal shrinkage of the film which can be detected by the present technique.

  6. An exposition on Friedmann cosmology with negative energy densities

    SciTech Connect

    Nemiroff, Robert J.; Joshi, Ravi; Patla, Bijunath R. E-mail: rjoshimtu@gmail.com

    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.

  7. Liquid density analysis of sucrose and alcoholic beverages using polyimide guided Love-mode acoustic wave sensors

    NASA Astrophysics Data System (ADS)

    Turton, Andrew; Bhattacharyya, Debabrata; Wood, David

    2006-02-01

    A liquid density sensor using Love-mode acoustic waves has been developed which is suitable for use in the food and drinks industries. The sensor has an open flat surface allowing immersion into a sample and simple cleaning. A polyimide waveguide layer allows cheap and simple fabrication combined with a robust chemically resistant surface. The low shear modulus of polyimide allows thin guiding layers giving a high sensitivity. A dual structure with a smooth reference device exhibiting viscous coupling with the wave, and a patterned sense area to trap the liquid causing mass loading, allows discrimination of the liquid density from the square root of the density-viscosity product (ρη)0.5. Frequency shift and insertion loss change were proportional to (ρη)0.5 with a non-linear response due to the non-Newtonian nature of viscous liquids at high frequencies. Measurements were made with sucrose solutions up to 50% and different alcoholic drinks. A maximum sensitivity of 0.13 µg cm-3 Hz-1 was achieved, with a linear frequency response to density. This is the highest liquid density sensitivity obtained for acoustic mode sensors to the best of our knowledge.

  8. Acoustic Metamaterials Through a Microfluidic, Bottom-up Approach: Toward Highly Attenuating, Negative Effective Density Materials

    DTIC Science & Technology

    2012-10-01

    material obtained through a microfluidic approach is shown on figure 1. In this approach, one can vary the average size and droplets volume fraction in the...AFRL-AFOSR-UK-TR-2012-0049 Acoustic metamaterials through a microfluidic , bottom-up approach: Toward highly attenuating, negative...2012 Final Report 26 Apr 2011 - 26 Sep 2012 Acoustic metamaterials through a microfluidic , bottom-up approach: Toward highly attenuating, negative

  9. Photospheric Magnetic Free Energy Density of Solar Active Regions

    NASA Astrophysics Data System (ADS)

    Zhang, Hongqi

    2016-12-01

    We present the photospheric energy density of magnetic fields in two solar active regions (one of them recurrent) inferred from observational vector magnetograms, and compare it with other available differently defined energy parameters of magnetic fields in the photosphere. We analyze the magnetic fields in Active Regions NOAA 6580-6619-6659 and 11158. The quantity 1/4π{B}n\\cdot{B}p is an important energy parameter that reflects the contribution of magnetic shear to the difference between the potential (Bp) and the non-potential magnetic field (Bn), and also the contribution to the free magnetic energy near the magnetic neutral lines in the active regions. It is found that the photospheric mean magnetic energy density shows clear changes before the powerful solar flares in Active Region NOAA 11158, which is consistent with the change in magnetic fields in the flaring lower atmosphere.

  10. Density functional theory for comprehensive orbital energy calculations.

    PubMed

    Nakata, Ayako; Tsuneda, Takao

    2013-08-14

    This study reveals the reason core 1s orbital energies and the highest occupied molecular orbital (HOMO) energies of hydrogen and rare gas atoms are underestimated by long-range corrected (LC) density functional theory (DFT), which quantitatively reproduces the HOMO energies of other systems and the lowest unoccupied molecular orbital (LUMO) energies. Applying the pseudospectral regional (PR) self-interaction correction (SIC) drastically improved the underestimated orbital energies in LC-DFT calculations, while maintaining or improving the accuracies in the calculated valence HOMO and LUMO energies. This indicates that the self-interaction error in exchange functionals causes the underestimations of core 1s orbital energies and the HOMO energies of hydrogen and rare gas atoms in LC-DFT calculations. To clarify the reason for the improvement, the fractional occupation dependences of total electronic energies and orbital energies were examined. The calculated results clearly showed that the LC-PR functional gives almost linear dependences of total electronic energies for a slight decrease in the occupation number of core 1s orbitals, although this linear dependence disappears for significant decrease due to the shrinking of exchange self-interaction regions. It was also clarified that the PRSIC hardly affects the occupation number dependences of the total electronic energies and orbital energies for the fractional occupations of HOMOs and LUMOs. As a result, it was concluded that core orbital energies are obtained accurately by combining LC-DFT with PRSIC.

  11. Electromagnetic field energy density in homogeneous negative index materials.

    PubMed

    Shivanand; Webb, Kevin J

    2012-05-07

    An exact separation of both electric and magnetic energies into stored and lost energies is shown to be possible in the special case when the wave impedance is independent of frequency. A general expression for the electromagnetic energy density in such a dispersive medium having a negative refractive index is shown to be accurate in comparison with numerical results. Using an example metamaterial response that provides a negative refractive index, it is shown that negative time-averaged stored energy can occur. The physical meaning of this negative energy is explained as the energy temporarily borrowed by the field from the material. This observation for negative index materials is of interest when approaching properties for a perfect lens. In the broader context, the observation of negative stored energy is of consequence in the study of dispersive materials.

  12. Enhanced acoustoelectric coupling in acoustic energy harvester using dual Helmholtz resonators.

    PubMed

    Peng, Xiao; Wen, Yumei; Li, Ping; Yang, Aichao; Bai, Xiaoling

    2013-10-01

    In this paper, enhanced acoustoelectric transduction in an acoustic energy harvester using dual Helmholtz resonators has been reported. The harvester uses a pair of cavities mechanically coupled with a compliant perforated plate to enhance the acoustic coupling between the cavity and the plate. The experimental results show that the volume optimization of the second cavity can significantly increase the generated electric voltage up to 400% and raise the output power to 16 times as large as that of a harvester using a single Helmholtz resonator at resonant frequencies primarily related to the plate.

  13. Broadband convergence of acoustic energy with binary reflected phases on planar surface

    NASA Astrophysics Data System (ADS)

    Fan, Xu-Dong; Zhu, Yi-Fan; Liang, Bin; Yang, Jing; Cheng, Jian-Chun

    2016-12-01

    We propose to produce efficient three-dimensional sound converging in broadband with binary reflected phases on a planar surface with unit cells consisting of only two kinds of elements. The mechanism is experimentally demonstrated by focusing airborne sound and by forming an "acoustic needle," with handmade arrays of commercial test tubes with/without lids. Both the simulated and measured results show the precise control of converging acoustic energy despite misalignment errors obvious even to naked eyes. Our approach with extreme simplicity yet good robustness may apply in various scenarios that conventionally need complicated elements and continuous variation of parameters for focusing sound.

  14. Design and Implementation of an Acoustic X-ray Detector to Measure the LCLS Beam Energy

    SciTech Connect

    Loos, Jennifer L.; /San Jose State U. /SLAC

    2010-08-25

    On April 11, 2009, first light was seen from LCLS. The present apparatus being used to measure the x-ray beam energy is the Total Energy Sensor which uses a suite of thermal sensors. Another device is needed to cross-check the energy measurements. This new diagnostic tool utilizes radiation acoustic phenomena to determine the x-ray beam energy. A target is hit by the x-rays from the beam, and a voltage is generated in two piezoelectric sensors attached to the target in response to the consequent deformation. Once the voltage is known, the power can be obtained. Thermal sensors will also be attached to the target for calibration purposes. Material selection and design were based on: durability, ultra-high vacuum compatibility, safety and thermal properties. The target material was also chosen for its acoustic properties which were determined from tests using a frequency generator and laser. Initial tests suggest the device will function as anticipated.

  15. 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.

  16. Multi-cavity coupling acoustic metamaterials with low-frequency broad band gaps based on negative mass density

    NASA Astrophysics Data System (ADS)

    Yang, Chuanhui; Wu, Jiu Hui; Cao, Songhua; Jing, Li

    2016-08-01

    This paper studies a novel kind of low-frequency broadband acoustic metamaterials with small size based on the mechanisms of negative mass density and multi-cavity coupling. The structure consists of a closed resonant cavity and an open resonant cavity, which can be equivalent to a homogeneous medium with effective negative mass density in a certain frequency range by using the parameter inversion method. The negative mass density makes the anti-resonance area increased, which results in broadened band gaps greatly. Owing to the multi-cavity coupling mechanism, the local resonances of the lower frequency mainly occur in the closed cavity, while the local resonances of the higher frequency mainly in the open cavity. Upon the interaction between the negative mass density and the multi-cavity coupling, there exists two broad band gaps in the range of 0-1800 Hz, i.e. the first-order band gap from 195 Hz to 660 Hz with the bandwidth of 465 Hz and the second-order band gap from 1157 Hz to 1663 Hz with the bandwidth of 506 Hz. The acoustic metamaterials with small size presented in this paper could provide a new approach to reduce the low-frequency broadband noises.

  17. 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.

  18. Density functional resonance theory: complex density functions, convergence, orbital energies, and functionals.

    PubMed

    Whitenack, Daniel L; Wasserman, Adam

    2012-04-28

    Aspects of density functional resonance theory (DFRT) [D. L. Whitenack and A. Wasserman, Phys. Rev. Lett. 107, 163002 (2011)], a recently developed complex-scaled version of ground-state density functional theory (DFT), are studied in detail. The asymptotic behavior of the complex density function is related to the complex resonance energy and system's threshold energy, and the function's local oscillatory behavior is connected with preferential directions of electron decay. Practical considerations for implementation of the theory are addressed including sensitivity to the complex-scaling parameter, θ. In Kohn-Sham DFRT, it is shown that almost all θ-dependence in the calculated energies and lifetimes can be extinguished via use of a proper basis set or fine grid. The highest occupied Kohn-Sham orbital energy and lifetime are related to physical affinity and width, and the threshold energy of the Kohn-Sham system is shown to be equal to the threshold energy of the interacting system shifted by a well-defined functional. Finally, various complex-scaling conditions are derived which relate the functionals of ground-state DFT to those of DFRT via proper scaling factors and a non-Hermitian coupling-constant system.

  19. High-Energy-Density Shear Flow and Instability Experiments

    NASA Astrophysics Data System (ADS)

    Doss, F. W.; Flippo, K. A.; Merritt, E. C.; di Stefano, C. A.; Devolder, B. G.; Kurien, S.; Kline, J. L.

    2016-10-01

    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 μm thick Al plate, variations of the experiment to details of the initial conditions have been performed. These variations have included increasing the fluid densities (by modifying the plate material from Al to Ti and Cu), imposing sinusoidal seed perturbations on the plate, and directly modifying the plate's intrinsic surface roughness. Radiography of the unseeded layer has revealed the presence of emergent Kelvin-Helmholtz structures which may be analyzed to infer fluid-mechanical properties including turbulent energy density. This work is conducted by the US DOE by LANL under contract DE-AC52-06NA25396.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. Energy-Based Acoustic Source Localization Methods: A Survey

    PubMed Central

    Meng, Wei; Xiao, Wendong

    2017-01-01

    Energy-based source localization is an important problem in wireless sensor networks (WSNs), which has been studied actively in the literature. Numerous localization algorithms, e.g., maximum likelihood estimation (MLE) and nonlinear-least-squares (NLS) methods, have been reported. In the literature, there are relevant review papers for localization in WSNs, e.g., for distance-based localization. However, not much work related to energy-based source localization is covered in the existing review papers. Energy-based methods are proposed and specially designed for a WSN due to its limited sensor capabilities. This paper aims to give a comprehensive review of these different algorithms for energy-based single and multiple source localization problems, their merits and demerits and to point out possible future research directions. PMID:28212281

  5. Energy-Based Acoustic Source Localization Methods: A Survey.

    PubMed

    Meng, Wei; Xiao, Wendong

    2017-02-15

    Energy-based source localization is an important problem in wireless sensor networks (WSNs), which has been studied actively in the literature. Numerous localization algorithms, e.g., maximum likelihood estimation (MLE) and nonlinear-least-squares (NLS) methods, have been reported. In the literature, there are relevant review papers for localization in WSNs, e.g., for distance-based localization. However, not much work related to energy-based source localization is covered in the existing review papers. Energy-based methods are proposed and specially designed for a WSN due to its limited sensor capabilities. This paper aims to give a comprehensive review of these different algorithms for energy-based single and multiple source localization problems, their merits and demerits and to point out possible future research directions.

  6. 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.

  7. Nuclear energy density functional and the nuclear α decay

    NASA Astrophysics Data System (ADS)

    Lim, Yeunhwan; Oh, Yongseok

    2017-03-01

    The nuclear α decay of heavy nuclei is investigated based on the nuclear energy density functional, which leads to the α potential inside the parent nucleus in terms of the proton and neutron density profiles of the daughter nucleus. We use the Skyrme force model, Gogny force model, and relativistic mean-field model to get the nucleon density profiles inside heavy nuclei. Once the nucleon density profiles are determined, the parameters of the nuclear α potential are fitted to the observed α decay half-lives of heavy nuclei. This approach is then applied to predict unknown α decay half-lives of heavy nuclei. To estimate the Q values of unobserved α decays, we make use of the liquid droplet model.

  8. Effect of wind and temperature gradients on received acoustic energy

    NASA Technical Reports Server (NTRS)

    Brienzo, Richard K.

    1990-01-01

    The effect of refraction due to wind and temperature gradients on energy received from low flying aircraft is examined. A series of helicopter and jet flyby's were recorded with a microphone array on two separate days, each with distinctly different meteorological conditions. Energy in the 100 to 200 Hertz band is shown as a function of aircraft range from the array, and compared with the output of the Fast Field Program.

  9. Energy transmission in a mechanically-linked double-wall structure coupled to an acoustic enclosure

    NASA Astrophysics Data System (ADS)

    Cheng, L.; Li, Y. Y.; Gao, J. X.

    2005-05-01

    The energy transmission in a mechanically linked double-wall structure into an acoustic enclosure is studied in this paper. Based on a fully coupled vibro-acoustic formulation, focus is put on investigating the effect of the air gap and mechanical links between the two panels on the energy transmission and noise insulation properties of such structures. An approximate formula reflecting the gap effect on the lower-order coupled frequencies of the system is proposed. A criterion, based on the ratio between the aerostatic stiffness of the gap cavity and the stiffness of the link, is proposed to predict the dominant transmitting path, with a view to provide guidelines for the design of appropriate control strategies. Numerical results reveal the existence of three distinct zones, within which energy transmission takes place following different mechanisms and transmitting paths. Corresponding effects on noise insulation properties of the double-wall structure are also investigated. .

  10. Effect of internal resistance of a Helmholtz resonator on acoustic energy reduction in enclosures.

    PubMed

    Yu, Ganghua; Li, Deyu; Cheng, Li

    2008-12-01

    The effect of internal resistance of a Helmholtz resonator on acoustic energy reduction in an enclosure and the multimodal coupling-based Helmholtz resonator design are investigated. Using the analytical solution of a resonator-enclosure interaction model, an energy reduction index is defined in a frequency band to optimize the resonator resistance. The dual process of energy dissipation and radiation of the resonator is quantified. Optimal resistance of the resonator and its physical effect on the resonator-enclosure interaction are numerically evaluated and categorized in terms of frequency bandwidths. Predictions on the resonator performance are confirmed by experiments. Comparisons with existing models based on different optimization criteria are also performed. It is shown that the proposed model serves as an effective design tool to determine the internal resistance of the resonator in order to achieve sound reduction in the frequency band enclosing acoustic resonances.

  11. Diagnostic group differences in temporomandibular joint energy densities

    PubMed Central

    Gallo, LM; Iwasaki, LR; Gonzalez, YM; Liu, H; Marx, DB; Nickel, JC

    2015-01-01

    Objectives Cartilage fatigue, due to mechanical work, may account for precocious development of degenerative joint disease in the temporomandibular joint (TMJ). This study compared energy densities (mJ/mm3) in TMJs of three diagnostic groups. Setting and Sample Population Sixty-eight subjects (44 women, 24 men) gave informed consent. Diagnostic criteria for temporomandibular disorders (DC/TMD) and imaging were used to group subjects according to presence of jaw muscle or joint pain (+P) and bilateral disc displacement (+DD). Material and Methods Subjects (+P+DD, n=16; −P+DD, n=16; and −P−DD, n=36) provided cone-beam computed tomography and magnetic resonance images, and jaw tracking data. Numerical modeling was used to determine TMJ loads (Fnormal). Dynamic stereometry was used to characterize individual-specific data of stress-field dynamics during 10 symmetrical jaw closing cycles. These data were used to estimate tractional forces (Ftraction). Energy densities were then calculated as W/Q(W=workdoneormechanicalenergyinput=tractionalforce×distanceofstress-fieldtranslation,Q=volumeofcartilage). ANOVA and Tukey-Kramer post-hoc analyses tested for intergroup differences. Results Mean ±standard error energy density for the +P+DD group was 12.7±1.5 mJ/mm3 and significantly greater (all adjusted p<0.04) when compared to −P+DD (7.4±1.4 mJ/mm3) and −P−DD (5.8±0.9 mJ/mm3) groups. Energy densities in −P+DD and −P−DD groups were not significantly different. Conclusion Diagnostic group differences in energy densities suggest that mechanical work may be a unique mechanism which contributes to cartilage fatigue in subjects with pain and disc displacement. PMID:25865545

  12. Using Passive and Active Acoustics to Examine Relationships of Cetacean and Prey Densities

    DTIC Science & Technology

    2015-09-30

    mounted on a glider running on two California Cooperative Oceanic Fisheries Investigations (CalCOFI) lines and passive as well as active acoustic...Southwest Fisheries Science Center. WORK COMPLETED A preliminary experiment was carried out (see section Results) that documented sound production

  13. 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.}

  14. Laser-Plasma Interactions in High-Energy Density Plasmas

    SciTech Connect

    Constantin, C G; Baldis, H A; Schneider, M B; Hinkel, D E; Langdon, A B; Seka, W; Bahr, R; Depierreaux, S

    2005-08-24

    Laser-plasma interactions (LPI) have been studied experimentally in high-temperature, high-energy density plasmas. The studies have been performed using the Omega laser at the Laboratory for Laser Energetics (LLE), Rochester, NY. Up to 10 TW of power was incident upon reduced-scale hohlraums, distributed in three laser beam cones. The hot hohlraums fill quickly with plasma. Late in the laser pulse, most of the laser energy is deposited at the laser entrance hole, where most of the LPI takes place. Due to the high electron temperature, the stimulated Raman scattering (SRS) spectrum extends well beyond {omega}{sub 0}/2, due to the Bohm-Gross shift. This high-temperature, high-energy density regime provides a unique opportunity to study LPI beyond inertial confinement fusion (ICF) conditions.

  15. Acoustic noise and pneumatic wave vortices energy harvesting on highways

    NASA Astrophysics Data System (ADS)

    Pogacian, S.; Bot, A.; Zotoiu, D.

    2012-02-01

    This paper is aimed to present the structure and the principle of a energy harvesting system that uses the air movement emanated from passing traffic to produce and accumulate electrical energy. Each of the system's elements consists of a inertial mass panel which oscillate when driving cars pass. The panel is attached to a linear electromagnetic mini generator (or/and some piezo electric micro generators) and at the time of passing, it produces energy which is store it in a supercapacitor or in a rechargeable battery. The concept can be applied to busy roads, and to high-frequented rail networks and it can work with street and road lighting, information panels and monitoring devices.

  16. Energy density functional for nuclei and neutron stars

    NASA Astrophysics Data System (ADS)

    Erler, J.; Horowitz, C. J.; Nazarewicz, W.; Rafalski, M.; Reinhard, P.-G.

    2013-04-01

    Background: Recent observational data on neutron star masses and radii provide stringent constraints on the equation of state of neutron rich matter [Annu. Rev. Nucl. Part. Sci.ARPSDF0163-899810.1146/annurev-nucl-102711-095018 62, 485 (2012)].Purpose: We aim to develop a nuclear energy density functional that can be simultaneously applied to finite nuclei and neutron stars.Methods: We use the self-consistent nuclear density functional theory (DFT) with Skyrme energy density functionals and covariance analysis to assess correlations between observables for finite nuclei and neutron stars. In a first step two energy functionals—a high density energy functional giving reasonable neutron properties, and a low density functional fitted to nuclear properties—are matched. In a second step, we optimize a new functional using exactly the same protocol as in earlier studies pertaining to nuclei but now including neutron star data. This allows direct comparisons of performance of the new functional relative to the standard one.Results: The new functional TOV-min yields results for nuclear bulk properties (energy, rms radius, diffraction radius, and surface thickness) that are of the same quality as those obtained with the established Skyrme functionals, including SV-min. When comparing SV-min and TOV-min, isoscalar nuclear matter indicators vary slightly while isovector properties are changed considerably. We discuss neutron skins, dipole polarizability, separation energies of the heaviest elements, and proton and neutron drip lines. We confirm a correlation between the neutron skin of 208Pb and the neutron star radius.Conclusions: We demonstrate that standard energy density functionals optimized to nuclear data do not carry information on the expected maximum neutron star mass, and that predictions can only be made within an extremely broad uncertainty band. For atomic nuclei, the new functional TOV-min performs at least as well as the standard nuclear functionals, but

  17. 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.

  18. Rayleigh criterion and acoustic energy balance in unconfined self-sustained oscillating flames

    SciTech Connect

    Durox, D.; Schuller, T.; Noiray, N.; Birbaud, A.L.; Candel, S.

    2008-11-15

    Instabilities of confined combustion systems are often discussed in terms of the Rayleigh criterion, which provides a necessary condition for unstable operation and is commonly used to distinguish driving and damping regions. The analysis is also carried out in some cases by making use of an acoustic energy balance in which the Rayleigh term acts as a source. The case of unconfined flames is less well documented but of importance in practical systems used in heating and drying. This study is motivated by problems of self-sustained oscillations of radiant burners for domestic or industrial processes and of various other types of open flames. Application of the Rayleigh criterion and of the balance of acoustic energy to oscillations arising in such unconfined systems is examined. The objective is to see if the Rayleigh condition is fulfilled and to show how the different perturbed variables are linked to each other to develop an unstable oscillation. These issues are investigated by experiments in two geometries. The first case relates to a single ''V''- or ''M''-shaped flame formed by a burner behaving like a Helmholtz resonator. The second geometry features a collection of conical flames (CCF) established by a multipoint injector. This system is fed by a manifold that features a set of plane modes and resonates like an organ pipe at frequencies corresponding to odd multiples of the quarter wave. The Rayleigh criterion and a related result written in the form of an acoustic energy balance are used to define conditions of instability. A link is established between the pressure signal radiated by the burner and the total heat release rate perturbation yielding the phase lag between these two variables and providing conditions for unstable operation. Systematic experiments carried out in the two burner geometries and model predictions are in good agreement indicating that the Rayleigh source term is positive and that the criterion is well fulfilled by the wavefield

  19. Rayleigh criterion and acoustic energy balance in unconfined self-sustained oscillating flames

    SciTech Connect

    Durox, D.; Schuller, T.; Noiray, N.; Birbaud, A.L.; Candel, S.

    2009-01-15

    Instabilities of confined combustion systems are often discussed in terms of the Rayleigh criterion, which provides a necessary condition for unstable operation and is commonly used to distinguish driving and damping regions. The analysis is also carried out in some cases by making use of an acoustic energy balance in which the Rayleigh term acts as a source. The case of unconfined flames is less well documented but of importance in practical systems used in heating and drying. This study is motivated by problems of self-sustained oscillations of radiant burners for domestic or industrial processes and of various other types of open flames. Application of the Rayleigh criterion and of the balance of acoustic energy to oscillations arising in such unconfined systems is examined. The objective is to see if the Rayleigh condition is fulfilled and to show how the different perturbed variables are linked to each other to develop an unstable oscillation. These issues are investigated by experiments in two geometries. The first case relates to a single ''V''- or ''M''-shaped flame formed by a burner behaving like a Helmholtz resonator. The second geometry features a collection of conical flames (CCF) established by a multipoint injector. This system is fed by a manifold that features a set of plane modes and resonates like an organ pipe at frequencies corresponding to odd multiples of the quarter wave. The Rayleigh criterion and a related result written in the form of an acoustic energy balance are used to define conditions of instability. A link is established between the pressure signal radiated by the burner and the total heat release rate perturbation yielding the phase lag between these two variables and providing conditions for unstable operation. Systematic experiments carried out in the two burner geometries and model predictions are in good agreement indicating that the Rayleigh source term is positive and that the criterion is well fulfilled by the wavefield

  20. Negative refraction and energy funneling by hyperbolic materials: an experimental demonstration in acoustics.

    PubMed

    García-Chocano, Victor M; Christensen, Johan; Sánchez-Dehesa, José

    2014-04-11

    This Letter reports the design, fabrication, and experimental characterization of hyperbolic materials showing negative refraction and energy funneling of airborne sound. Negative refraction is demonstrated using a stack of five holey Plexiglas plates where their thicknesses, layer separation, hole diameters, and lattice periodicity have been determined to show hyperbolic dispersion around 40 kHz. The resulting hyperbolic material shows a flat band profile in the equifrequency contour allowing the gathering of acoustic energy in a broad range of incident angles and its funneling through the material. Our demonstrations foresee interesting developments based on both phenomena. Acoustic imaging with subwavelength resolution and spot-size converters that harvest and squeeze sound waves irradiating from many directions into a collimated beam are just two possible applications among many.

  1. Microelectromechanical high-density energy storage/rapid release system

    NASA Astrophysics Data System (ADS)

    Rodgers, M. Steven; Allen, James J.; Meeks, Kent D.; Jensen, Brian D.; Miller, Samuel L.

    1999-08-01

    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.

  2. Linear response of homogeneous nuclear matter with energy density functionals

    NASA Astrophysics Data System (ADS)

    Pastore, A.; Davesne, D.; Navarro, J.

    2015-03-01

    Response functions of infinite nuclear matter with arbitrary isospin asymmetry are studied in the framework of the random phase approximation. The residual interaction is derived from a general nuclear Skyrme energy density functional. Besides the usual central, spin-orbit and tensor terms it could also include other components as new density-dependent terms or three-body terms. Algebraic expressions for the response functions are obtained from the Bethe-Salpeter equation for the particle-hole propagator. Applications to symmetric nuclear matter, pure neutron matter and asymmetric nuclear matter are presented and discussed. Spin-isospin strength functions are analyzed for varying conditions of density, momentum transfer, isospin asymmetry, and temperature for some representative Skyrme functionals. Particular attention is paid to the discussion of instabilities, either real or unphysical, which could manifest in finite nuclei.

  3. Study of Volumetrically Heated Ultra-High Energy Density Plasmas

    SciTech Connect

    Rocca, Jorge J.

    2016-10-27

    Heating dense matter to millions of degrees is important for applications, but requires complex and expensive methods. The major goal of the project was to demonstrate using a compact laser the creation of a new ultra-high energy density plasma regime characterized by simultaneous extremely high temperature and high density, and to study it combining experimental measurements and advanced simulations. We have demonstrated that trapping of intense femtosecond laser pulses deep within ordered nanowire arrays can heat near solid density matter into a new ultra hot plasma regime. Extreme electron densities, and temperatures of several tens of million degrees were achieved using laser pulses of only 0.5 J energy from a compact laser. Our x-ray spectra and simulations showed that extremely highly ionized plasma volumes several micrometers in depth are generated by irradiation of gold and Nickel nanowire arrays with femtosecond laser pulses of relativistic intensities. We obtained extraordinarily high degrees of ionization (e.g. we peeled 52 electrons from gold atoms, and up to 26 electrons from nickel atoms). In the process we generated Gigabar pressures only exceeded in the central hot spot of highly compressed thermonuclear fusion plasmas.. The plasma created after the dissolved wires expand, collide, and thermalize, is computed to have a thermal energy density of 0.3 GJ cm-3 and a pressure of 1-2 Gigabar. These are pressures only exceeded in highly compressed thermonuclear fusion plasmas. Scaling these results to higher laser intensities promises to create plasmas with temperatures and pressures exceeding those in the center of the sun.

  4. Relaxor-ferroelectric superlattices: high energy density capacitors

    NASA Astrophysics Data System (ADS)

    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 BaTiO3/Ba(1-x)SrxTiO3 (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 (Tm) with a merger above Tm 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 Tm 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. High Energy Density Non-Aqueous Battery System.

    DTIC Science & Technology

    1983-05-31

    otherwise attractive couple from use. In this report are included, the corrosion studies of calcium and calcium lithium alloys in thionyl chloride ... lithium battery systems have been developed to fulfill the need for long shelf life high energy density batteries. The lithium - thionyl chloride system has... lithium - thionyl chloride battery claimed one life and two injuries (2) (4th of August 1976, Ogden, Utah). Thus lithium batteries have not reached the

  10. 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

  11. High Energy Density Dielectrics for Pulsed Power Applications

    DTIC Science & Technology

    2008-09-01

    next page). 14. ABSTRACT This report was developed under a SBIR contract. Aluminum oxynitride (AlON) capacitors exhibit several promising...characteristics for high energy density capacitor applications in extreme environments. Dielectric constants in the range of 9 and dielectric strength in...properties remain stable from cryogenic temperatures of -200 °C to temperatures above 400 °C. Stacked capacitor devices have been developed and

  12. High energy density capacitor testing for the AFWL SHIVA

    NASA Astrophysics Data System (ADS)

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

    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 microsec quarter period. Dielectric systems including Kraft paper with caster oil impregnant and Kraft paper, polypropylene with DiOctyl Phthalate (DOP) impregnant were tested.

  13. 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

  14. Optimizing liner implosions for high energy density physics experiments

    SciTech Connect

    Ekdahl, C.; Humphries, S. Jr.

    1996-12-31

    Cylindrical metal shells imploded by magnetic fields - liners - are used as kinetic energy drivers for high energy density physics experiments in hydrodynamics and dynamic material property measurements. There are at least three ways in which liners have been, or are expected to be, used to produce high energy density, i.e., high pressure, in target materials. A common approach uses the liner as a convergent flyer plate, which impacts a material target cylinder after having been shocklessly accelerated across an intervening gap. The resultant shock and piston hydrodynamic flow in the target are used in exploration of a wide variety of phenomena and material properties. Another common method is to slowly compress a liner containing a material sample in a such fashion that little heating occurs. This technique is most useful for investigated physical properties at low temperature and extreme density. Finally, one can use a hybrid approach to shock heat with an impacting liner followed by slower adiabatic, if not isentropic, compression to explore material properties in extrema. The magnetic fields for driving these liners may be produced by either high explosive pulsed power generators or by capacitor banks. Here we will consider only capacitor banks.

  15. Correlations between acoustic properties and bone density in bovine cancellous bone from 0.5 to 2 MHz

    NASA Astrophysics Data System (ADS)

    Lee, Kang Il; Roh, Heui-Seol; Yoon, Suk Wang

    2003-05-01

    Correlations between acoustic properties and bone density were investigated in the 12 defatted bovine cancellous bone specimens in vitro. Speed of sound (SOS) and broadband ultrasonic attenuation (BUA) were measured in three different frequency bandwidths from 0.5 to 2 MHz using three matched pairs of transducers with the center frequencies of 1, 2.25, and 3.5 MHz. The relative orientation between ultrasonic beam and bone specimen was the mediolateral (ML) direction of the bovine tibia. SOS shows significant linear positive correlation with apparent density for all three pairs of transducers. However, BUA shows relatively weak correlation with apparent density. SOS and BUA are only weakly correlated with each other. The linear combination of SOS and BUA in a multiple regression model leads to a significant improvement in predicting apparent density. The correlations among SOS, BUA, and bone density can be effectively and clearly represented in the three-dimensional space by the multiple regression model. These results suggest that the frequency range up to 1.5 MHz and the multiple regression model in the three-dimensional space can be useful in the osteoporosis diagnosis.

  16. Blue whales (Balaenoptera musculus) optimize foraging efficiency by balancing oxygen use and energy gain as a function of prey density.

    PubMed

    Hazen, Elliott Lee; Friedlaender, Ari Seth; Goldbogen, Jeremy Arthur

    2015-10-01

    Terrestrial predators can modulate the energy used for prey capture to maximize efficiency, but diving animals face the conflicting metabolic demands of energy intake and the minimization of oxygen depletion during a breath hold. It is thought that diving predators optimize their foraging success when oxygen use and energy gain act as competing currencies, but this hypothesis has not been rigorously tested because it has been difficult to measure the quality of prey that is targeted by free-ranging animals. We used high-resolution multisensor digital tags attached to foraging blue whales (Balaenoptera musculus) with concurrent acoustic prey measurements to quantify foraging performance across depth and prey density gradients. We parameterized two competing physiological models to estimate energy gain and expenditure based on foraging decisions. Our analyses show that at low prey densities, blue whale feeding rates and energy intake were low to minimize oxygen use, but at higher prey densities feeding frequency increased to maximize energy intake. Contrary to previous paradigms, we demonstrate that blue whales are not indiscriminate grazers but instead switch foraging strategies in response to variation in prey density and depth to maximize energetic efficiency.

  17. Blue whales (Balaenoptera musculus) optimize foraging efficiency by balancing oxygen use and energy gain as a function of prey density

    PubMed Central

    Hazen, Elliott Lee; Friedlaender, Ari Seth; Goldbogen, Jeremy Arthur

    2015-01-01

    Terrestrial predators can modulate the energy used for prey capture to maximize efficiency, but diving animals face the conflicting metabolic demands of energy intake and the minimization of oxygen depletion during a breath hold. It is thought that diving predators optimize their foraging success when oxygen use and energy gain act as competing currencies, but this hypothesis has not been rigorously tested because it has been difficult to measure the quality of prey that is targeted by free-ranging animals. We used high-resolution multisensor digital tags attached to foraging blue whales (Balaenoptera musculus) with concurrent acoustic prey measurements to quantify foraging performance across depth and prey density gradients. We parameterized two competing physiological models to estimate energy gain and expenditure based on foraging decisions. Our analyses show that at low prey densities, blue whale feeding rates and energy intake were low to minimize oxygen use, but at higher prey densities feeding frequency increased to maximize energy intake. Contrary to previous paradigms, we demonstrate that blue whales are not indiscriminate grazers but instead switch foraging strategies in response to variation in prey density and depth to maximize energetic efficiency. PMID:26601290

  18. Comment on "Anomalous wave propagation in a one-dimensional acoustic metamaterial having simultaneously negative mass density and Young's modulus" [J. Acoust. Soc. Am. 132, 2887-2895 (2012)].

    PubMed

    Marston, Philip L

    2014-03-01

    The phase and group velocities of elastic guided waves are important in the physical interpretation of high frequency scattering by fluid-loaded elastic shells. Outside the context of scattering, those properties are also important for understanding the energy flow in acoustic metamaterials. In a recent investigation of acoustic metamaterials exhibiting anomalous wave propagation [J. Acoust. Soc. Am. 132, 2887-2895 (2012)] criticism of negative group velocity terminology was generalized to elastic waves guided on ordinary materials. Some context and justification for retaining the identification of negative group velocities associated with a type of backscattering enhancement for shells are explained here. The phase evolution direction is determined by the boundary conditions.

  19. 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.

  20. Is it possible to obtain cosmic accelerated expansion through energy transfer between different energy densities?

    NASA Astrophysics Data System (ADS)

    Erdem, Recai

    2017-03-01

    The equation of state of an energy density may be significantly modified by coupling it to another energy density. In the light of this observation we check the possibility of producing cosmic accelerated expansion in this way. In particular we consider the case where matter is converted to radiation (or vice versa by particle physics processes). We find that cosmic accelerated expansion can be obtained in this way only if an intermediate state with negative equation of state forms during the conversion.

  1. 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.

  2. Development of high energy density electrical double layer capacitors

    NASA Astrophysics Data System (ADS)

    Devarajan, Thamarai selvi

    Electrochemical Double Layer capacitors (EDLCs) have shown themselves as a viable energy storage alternative. EDLCs have high power density, faster charge/discharge, wide operating temperature and long cycle life compared to batteries since it stores charge by physical separation. Despites all their advantages, their low energy density stand as a bottleneck for capacitors. This research aims to increase the energy density of EDLC without compromising the power density. Energy is proportional to the square of cell voltage. Cell voltage is mainly dependent on electrolyte breakdown. Electrolytes also provide ions for charge separation and conduction. Therefore various electrolytes (Solutes and Solvents) which can give high concentration, solubility and decomposition potential were characterized in the first part of the research. In that study, a novel ionic liquid OPBF4 had higher capacitance and comparable voltage window compared to commercial TEABF4 in Acetonitrile. However, the increased polarity of the fixed ring O-atom and the ion-ion interaction in OPBF4 was responsible for lowering its conductivity. Oxygenated ionic compounds with alkyl groups had lower stability due to beta elimination between two electron withdrawing atoms. Volume based thermodynamics and quantum chemical calculations were used to calculate ion size, HOMO/LUMO energies, and free energy changes and establish relationship with capacitance, redox potential and melting points respectively. In addition free energy of fusion was used to predict the melting point. Ion size had correlation with capacitance due to compact double layer formation. Free energy changes did not explain the differences in melting point and predicted dielectric constant was inconsistent with the polarity. This is presumably due to using Van der Waals volume instead of crystal structure volume and insufficient incorporation of polarization term. The HOMO/LUMO energies gave direct relation between oxidation and reduction

  3. 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.

  4. 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.

  5. Effective parameters in beam acoustic metamaterials based on energy band structures

    NASA Astrophysics Data System (ADS)

    Jing, Li; Wu, Jiu Hui; Guan, Dong; Hou, Mingming; Kuan, Lu; Shen, Li

    2016-07-01

    We present a method to calculate the effective material parameters of beam acoustic metamaterials. The effective material parameters of a periodic beam are calculated as an example. The dispersion relations and energy band structures of this beam are calculated. Subsequently, the effective material parameters of the beam are investigated by using the energy band structures. Then, the modal analysis and transmission properties of the beams with finite cells are simulated in order to confirm the correctness of effective approximation. The results show that the periodic beam can be equivalent to the homogeneous beam with dynamic effective material parameters in passband.

  6. "Sloppy" nuclear energy density functionals: Effective model reduction

    NASA Astrophysics Data System (ADS)

    Nikšić, Tamara; Vretenar, Dario

    2016-08-01

    Concepts from information geometry are used to analyze parameter sensitivity for a nuclear energy density functional, representative of a class of semiempirical functionals that start from a microscopically motivated ansatz for the density dependence of the energy of a system of protons and neutrons. It is shown that such functionals are "sloppy," namely, characterized by an exponential range of sensitivity to parameter variations. Responsive to only a few stiff parameter combinations, sloppy functionals exhibit an exponential decrease of sensitivity to variations of the remaining soft parameters. By interpreting the space of model predictions as a manifold embedded in the data space, with the parameters of the functional as coordinates on the manifold, it is also shown that the exponential distribution of model manifold widths corresponds to the range of parameter sensitivity. Using the manifold boundary approximation method, we illustrate how to systematically construct effective nuclear density functionals of successively lower dimension in parameter space until sloppiness is eventually eliminated and the resulting functional contains only stiff combinations of parameters.

  7. Acoustical Detection of High-Density Krill Demersal Layers in the Submarine Canyons off Georges Bank.

    PubMed

    Greene, C H; Wiebe, P H; Burczynski, J; Youngbluth, M J

    1988-07-15

    High-density demersal layers of krill have been detected in the submarine canyons off Georges Bank by means of a high-frequency, dual-beam bioacoustical technique. Krill densities in these demersal layers were observed to be two to three orders of magnitude greater than the highest densities observed in water-column scattering layers. Such abundances may help explain the unusually high squid and demersal fish production estimates attributed to the Georges Bank ecosystem.

  8. Lead-Zirconate-Titanate Acoustic Energy Harvesters with Dual Top Electrodes

    NASA Astrophysics Data System (ADS)

    Tomioka, Shungo; Kimura, Shu; Tsujimoto, Kyohei; Iizumi, Satoshi; Uchida, Yusuke; Tomii, Kazuki; Matsuda, Tomohiro; Nishioka, Yasushiro

    2011-09-01

    In this paper, we present the power generation performances of a lead-zirconate-titanate (PZT) microelectromechanical system (MEMS) acoustic energy harvester having dual top electrodes to utilize the different polarizations of charges on the surface of a vibrating PZT diaphragm at first resonance. The PZT acoustic energy harvester had a diaphragm with a diameter of 2 mm consisting of Al (0.1 µm)/PZT (1 µm)/Pt (0.1 µm)/Ti (0.1 µm)/SiO2 (1.5 µm), and the diaphragm vibrations were excited by sound pressure. The top Al electrodes independently cover the peripheral surface and the central surface of the PZT diaphragm. The peripheral energy harvester generated a power of 5.28×10-11 W, and the central energy harvester generated a power of 4.25×10-11 W at a sound pressure level of 100 dB (0.01 W/m2) at 4.92 kHz. Thus, nearly 80% of the total power of the energy harvesters can be increased by utilizing the polarization at the central part of the diaphragm, which was usually not considered when only the peripheral part of the diaphragm was utilized.

  9. 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.

  10. 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.

  11. The photonic density of states and the light energy density in cholesteric liquid crystal cells

    NASA Astrophysics Data System (ADS)

    Gevorgyan, A. H.; Oganesyan, K. B.; Karapetyan, R. V.; Rafayelyan, M. S.

    2013-12-01

    The photonic density of states (PDS) of the eigen polarizations (EPs) in cholesteric liquid crystal (CLC) cells are calculated. The dependences of the PDS on the parameters characterizing absorption, gain and refractive index of the CLC layer surroundings were obtained. We investigated the possibility of connections between the PDS and the density of the light energy accumulated in the medium and showed that these characteristics have analogous spectra and, besides, the influences of the problem parameters on these characteristics also are analogous. It was shown that the decrement of the refractive index of the CLC layer surroundings leads to a sharp increase of the maximum PDS and, consequently, leads to a sharp decrement of the laser excitation threshold. We showed that the subject system can work as a low threshold laser or a multi-position trigger.

  12. Hydrodynamic Instabilities in High-Energy-Density Settings

    NASA Astrophysics Data System (ADS)

    Smalyuk, Vladimir

    2016-10-01

    Our understanding of hydrodynamic instabilities, such as the Rayleigh-Taylor (RT), Richtmyer-Meshkov (RM), and Kelvin-Helmholtz (KH) instabilities, in high-energy-density (HED) settings over past two decades has progressed enormously. The range of conditions where hydrodynamic instabilities are experimentally observed now includes direct and indirect drive inertial confinement fusion (ICF) where surprises continue to emerge, linear and nonlinear regimes, classical interfaces vs. stabilized ablation fronts, tenuous ideal plasmas vs. high density Fermi degenerate plasmas, bulk fluid interpenetration vs. mixing down to the atomic level, in the presence of magnetic fields and/or intense radiation, and in solid state plastic flow at high pressures and strain rates. Regimes in ICF can involve extreme conditions of matter with temperatures up to kilovolts, densities of a thousand times solid densities, and time scales of nanoseconds. On the other hand, scaled conditions can be generated that map to exploding stars (supernovae) with length and time scales of millions of kilometers and hours to days or even years of instability evolution, planetary formation dynamics involving solid-state plastic flow which severely modifies the RT growth and continues to challenge reliable theoretical descriptions. This review will look broadly at progress in probing and understanding hydrodynamic instabilities in these very diverse HED settings, and then will examine a few cases in more depth to illustrate the detailed science involved. Experimental results on large-scale HED facilities such as the Omega, Nike, Gekko, and Shenguang lasers will be reviewed and the latest developments at the National Ignition Facility (NIF) and Z machine will be covered. Finally, current overarching questions and challenges will be summarized to motivate research directions for future. This work was performed under the auspices of the U.S. Department of Energy by LLNL under Contract DE-AC52-07NA27344.

  13. 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

  14. 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.

  15. One-dimensional hydrodynamic simulation of high energy density experiments

    NASA Astrophysics Data System (ADS)

    Grinenko, A.

    2009-07-01

    A new one-dimensional hydrodynamic code for simulation of experiments involving the creation of high energy density in matter by means of laser or heavy ion beam irradiation is described. The code uses well-tested second order Lagrangian scheme in combination with the flux-limited van Leer convection algorithm for re-mapping to an arbitrary grid. Simple test cases with self-similar solutions are examined. Finally, the heating of solid targets by lasers and ions beams is investigated as examples.

  16. 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.

  17. 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.

  18. Ultralow frequency acoustic bandgap and vibration energy recovery in tetragonal folding beam phononic crystal

    NASA Astrophysics Data System (ADS)

    Gao, Nansha; Wu, Jiu Hui; Yu, Lie; Hou, Hong

    2016-06-01

    This paper investigates ultralow frequency acoustic properties and energy recovery of tetragonal folding beam phononic crystal (TFBPC) and its complementary structure. The dispersion curve relationships, transmission spectra and displacement fields of the eigenmodes are studied with FEA in detail. Compared with the traditional three layer phononic crystal (PC) structure, this structure proposed in this paper not only unfold bandgaps (BGs) in lower frequency range (below 300 Hz), but also has lighter weight because of beam structural cracks. We analyze the relevant physical mechanism behind this phenomenon, and discuss the effects of the tetragonal folding beam geometric parameters on band structure maps. FEM proves that the multi-cell structures with different arrangements have different acoustic BGs when compared with single cell structure. Harmonic frequency response and piezoelectric properties of TFBPC are specifically analyzed. The results confirm that this structure does have the recovery ability for low frequency vibration energy in environment. These conclusions in this paper could be indispensable to PC practical applications such as BG tuning and could be applied in portable devices, wireless sensor, micro-electro mechanical systems which can recycle energy from vibration environment as its own energy supply.

  19. Nonlinear coupling of acoustic and shear mode in a strongly coupled dusty plasma with a density dependent viscosity

    NASA Astrophysics Data System (ADS)

    Garai, S.; Janaki, M. S.; Chakrabarti, N.

    2016-09-01

    The nonlinear propagation of low frequency waves, in a collisionless, strongly coupled dusty plasma (SCDP) with a density dependent viscosity, has been studied with a proper Galilean invariant generalized hydrodynamic (GH) model. The well known reductive perturbation technique (RPT) has been employed in obtaining the solutions of the longitudinal and transverse perturbations. It has been found that the nonlinear propagation of the acoustic perturbations govern with the modified Korteweg-de Vries (KdV) equation and are decoupled from the sheared fluctuations. In the regions, where transversal gradients of the flow exists, coupling between the longitudinal and transverse perturbations occurs due to convective nonlinearity which is true for the homogeneous case also. The results, obtained here, can have relative significance to astrophysical context as well as in laboratory plasmas.

  20. Anharmonic damping of terahertz acoustic waves in a network glass and its effect on the density of vibrational states.

    PubMed

    Baldi, G; Giordano, V M; Ruta, B; Dal Maschio, R; Fontana, A; Monaco, G

    2014-03-28

    We report the observation, by means of high-resolution inelastic x-ray scattering, of an unusually large temperature dependence of the sound attenuation of a network glass at terahertz frequency, an unprecedentedly observed phenomenon. The anharmonicity can be ascribed to the interaction between the propagating acoustic wave and the bath of thermal vibrations. At low temperatures the sound attenuation follows a Rayleigh-Gans scattering law. As the temperature is increased the anharmonic process sets in, resulting in an almost quadratic frequency dependence of the damping in the entire frequency range. We show that the temperature variation of the sound damping accounts quantitatively for the temperature dependence of the density of vibrational states.

  1. Cheap DECAF: Density Estimation for Cetaceans from Acoustic Fixed Sensors Using Separate, Non-Linked Devices

    DTIC Science & Technology

    2014-09-30

    was repeated every 5 days throughout the year, and a video was produced showing fin whale density over the course of the year. RESULTS Fin...whale density was estimated across the area of the hydrophone array over the course of the year and a video was produced. This video , and the methods...America (Mellinger et al. 2014). Figure 4 shows a frame from this video . A paper about this work is also in preparation for submission to J

  2. High density continuous production of murine pluripotent cells in an acoustic perfused bioreactor at different oxygen concentrations.

    PubMed

    Baptista, Ricardo P; Fluri, David A; Zandstra, Peter W

    2013-02-01

    Strategies for the production of pluripotent stem cells (PSCs) rely on serially dissociated adherent or aggregate-based culture, consequently limiting robust scale-up of cell production, on-line control and optimization of culture conditions. We recently developed a method that enables continuous (non-serially dissociated) suspension culture-mediated reprogramming to pluripotency. Herein, we use this method to demonstrate the scalable production of PSCs and early derivatives using acoustic filter technology to enable continuous oxygen-controlled perfusion culture. Cell densities of greater than 1 × 10⁷  cells/mL were achieved after 7 days of expansion at a specific growth rate (µ) of 0.61 ± 0.1 day⁻¹ with a perfusion rate (D) of 5.0 day⁻¹. A twofold increase in maximum cell density (to greater than 2.5 × 10⁷  cells/mL) was achieved when the medium dissolved oxygen was reduced (5% DO). Cell densities and viabilities >80% were maintained for extended production periods during which maintenance of pluripotency was confirmed by stable expression of pluripotency factors (SSEA-1 and Nanog), as well as the capacity to differentiate into all three germ layers. This work establishes a versatile biotechnological platform for the production of pluripotent cells and derivatives in an integrated, scalable and intensified stirred suspension culture.

  3. High-Energy-Density Physics, with Applications to Astrophysics*

    NASA Astrophysics Data System (ADS)

    Remington, Bruce A.

    2002-04-01

    High-energy-density (HED) physics broadly refers to the study of collections of matter under extreme conditions of pressure, temperature, and density. The experimental facilities used for these studies are high power lasers, magnetic pinch generators, and charged particle beams. The HED physics pursued on these facilities is still in its infancy, yet a broad user community has nucleated, and new regimes of experimental science are emerging. [1, 2] Examples drawn from astrophysics include work relevant to supernovae and supernova remnants, astrophysical jets, radiatively driven molecular clouds, accreting black holes, planetary interiors, and gamma-ray bursts. A selection of science highlights in this field from the past decade will be reviewed, and a look ahead to the coming decade will be given. *This work was performed under the auspices of the U.S. Department of Energy by the Lawrence Livermore National Laboratory under Contract No. W-7405-ENG-48. 1. B.A. Remington, D. Arnett, R.P. Drake, and H. Takabe, Science 284, 1488 (1999); Phys. Plasmas 7, 1641 (2000). 2. Hideaki Takabe, Prog. Theor. Phys. Suppl. 143, 202 (2001).

  4. 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.

  5. 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.

  6. Ultrathin, rollable, paper-based triboelectric nanogenerator for acoustic energy harvesting and self-powered sound recording.

    PubMed

    Fan, Xing; Chen, Jun; Yang, Jin; Bai, Peng; Li, Zhaoling; Wang, Zhong Lin

    2015-04-28

    A 125 μm thickness, rollable, paper-based triboelectric nanogenerator (TENG) has been developed for harvesting sound wave energy, which is capable of delivering a maximum power density of 121 mW/m(2) and 968 W/m(3) under a sound pressure of 117 dBSPL. The TENG is designed in the contact-separation mode using membranes that have rationally designed holes at one side. The TENG can be implemented onto a commercial cell phone for acoustic energy harvesting from human talking; the electricity generated can be used to charge a capacitor at a rate of 0.144 V/s. Additionally, owing to the superior advantages of a broad working bandwidth, thin structure, and flexibility, a self-powered microphone for sound recording with rolled structure is demonstrated for all-sound recording without an angular dependence. The concept and design presented in this work can be extensively applied to a variety of other circumstances for either energy-harvesting or sensing purposes, for example, wearable and flexible electronics, military surveillance, jet engine noise reduction, low-cost implantable human ear, and wireless technology applications.

  7. 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

  8. 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

  9. 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

  10. 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.

  11. Advances in microbial biofilm prevention on indwelling medical devices with emphasis on usage of acoustic energy.

    PubMed

    Dror, Naama; Mandel, Mathilda; Hazan, Zadik; Lavie, Gad

    2009-01-01

    Microbial biofilms are a major impediment to the use of indwelling medical devices, generating device-related infections with high morbidity and mortality. Major efforts directed towards preventing and eradicating the biofilm problem face difficulties because biofilms protect themselves very effectively by producing a polysaccharide coating, reducing biofilm sensitivity to antimicrobial agents. Techniques applied to combating biofilms have been primarily chemical. These have met with partial and limited success rates, leading to current trends of eradicating biofilms through physico-mechanical strategies. Here we review the different approaches that have been developed to control biofilm formation and removal, focusing on the utilization of acoustic energy to achieve these objectives.

  12. Study of Acoustic Ultra-High Energy Neutrino Detection Phase II

    NASA Astrophysics Data System (ADS)

    Kurahashi, N.

    The Study of Acoustic Ultra-high energy Neutrino Detection has started its second phase (SAUND II). Although the general location of the hydrophones has not changed, SAUND II uses a new hydrophone array that uses a fiber-optic cable to connect to shore. Changes associated with the new hydrophone array as well as a new DAQ system that incorporates multiprocessor computing and accurate GPS timestamping are reported. Initial data of lightbulb calibration conducted in March 2005, and a future plan for a more accurate calibration are also presented.

  13. 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.

  14. High-Energy Density science with an ultra-bright x-ray laser

    NASA Astrophysics Data System (ADS)

    Glenzer, Siegfried

    2015-11-01

    This talk will review recent progress in high-energy density physics using the world's brightest x-ray source, the Linac Coherent Light Source, SLAC's free electron x-ray laser. These experiments investigate laser-driven matter in extreme conditions where powerful x-ray scattering and imaging techniques have been applied to resolve ionic interactions at atomic (Ångstrom) scale lengths and to visualize the formation of dense plasma states. Major research areas include dynamic compression experiments of solid targets to determine structural properties and to discover and characterize phase transitions at mega-bar pressures. A second area studies extreme fields produced by high-intensity radiation where fundamental questions of laboratory plasmas can be related to cosmological phenomena. Each of these areas takes advantage of the unique properties of the LCLS x-ray beam. They include small foci for achieving high intensity or high spatial resolution, high photon flux for dynamic structure factor measurements in single shots, and high spectral bandwidth to resolve plasmon (Langmuir) waves or ion acoustic waves in dense plasmas. We will further describe new developments of ultrafast pump-probe technique at high repetition rates. These include studies on dense cryogenic hydrogen that have begun providing fundamental insights into the physical properties of matter in extreme conditions that are important for astrophysics, fusion experiments and generation of radiation sources. This work was supported by DOE Office of Science, Fusion Energy Science under FWP 100182.

  15. Energy density of standing sound waves at the radiation-dominated phase of the universe expansion (hydrodynamic derivation)

    NASA Astrophysics Data System (ADS)

    Inogamov, N. A.; Sunyaev, R. A.

    2015-12-01

    In the early Universe up to hydrogen recombination in the Universe, the radiation pressure was much greater than the pressure of baryons and electrons. Moreover, the energy density of cosmic microwave background (CMB) photons was greater than or close to the energy density contained in the rest mass of baryonic matter, i.e., the primordial plasma was a radiated-dominated one and the adiabatic index was close to 4/3. The small density perturbations from which the observed galaxies have grown grew as long as the characteristic perturbation scales exceeded the horizon of the Universe сt at that time. On smaller scales, the density perturbations were standing sound waves. Radiative viscosity and heat conduction must have led to the damping of sound waves on very small scales. After the discovery of the cosmic microwave background, J. Silk calculated the scales of this damping, which is now called Silk damping, knowing the CMBtemperature and assuming the density of baryons and electrons. Observations with the South Pole Telescope, the Atacama Cosmology Telescope, and the Planck satellite have revealed the predicted damping of acoustic peaks in the CMB power spectrum and confirmed one important prediction of the theory. In 1970, R.A. Sunyaev and Ya.B. Zeldovich showed that such energy release in the early Universe should lead to characteristic deviations of the CMB spectrum from the Planck one. The development of the technology of cryogenic detectors of submillimeter and millimeter wavelength radiation has made it possible to measure the CMB spectral distortions at 10-8 of its total intensity (PIXIE). This has sharply increased the interest of theoretical cosmologists in the problem of energy release when smallscale sound waves are damped. We have derived a relativistic formula for the energy of a standing sound wave in a photon-baryon-electron plasma from simple hydrodynamic and thermodynamic relations. This formula is applicable for an arbitrary relation between the

  16. International Workshop on Detection, Classification and Localization of Marine Mammals Using Passive Acoustics (4th). International Workshop on Density Estimation of Marine Mammals Using Passive Acoustics (1st)

    DTIC Science & Technology

    2009-09-13

    Mars 55 Characterisation of sound subunits for humpback whale song analysis. F. Pace, P.R. White, O. Adam 56 Passive acoustic detection of Minke...International Monitoring System. Samaran Flore, Adam Olivier, Guinet Christophe 58 Detection of Minke whale sounds in the Stellwagen Bank National Marine...September 8.40 Characterisation of sound subunits for humpback whale song analysis. F. Pace, P.R. White, O. Adam 9.00 Passive acoustic detection of

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

    NASA Astrophysics Data System (ADS)

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

    2016-10-01

    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.

  18. 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.

  19. 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.

  20. Many-body theory and Energy Density Functionals

    NASA Astrophysics Data System (ADS)

    Baldo, M.

    2016-07-01

    In this paper a method is first presented to construct an Energy Density Functional on a microscopic basis. The approach is based on the Kohn-Sham method, where one introduces explicitly the Nuclear Matter Equation of State, which can be obtained by an accurate many-body calculation. In this way it connects the functional to the bare nucleon-nucleon interaction. It is shown that the resulting functional can be performing as the best Gogny force functional. In the second part of the paper it is shown how one can go beyond the mean-field level and the difficulty that can appear. The method is based on the particle-vibration coupling scheme and a formalism is presented that can handle the correct use of the vibrational degrees of freedom within a microscopic approach.

  1. 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.

  2. Diagnostics for ion beam driven high energy density physics experiments.

    PubMed

    Bieniosek, F M; Henestroza, E; Lidia, S; Ni, P A

    2010-10-01

    Intense beams of heavy ions are capable of heating volumetric samples of matter to high energy density. Experiments are performed on the resulting warm dense matter (WDM) at the NDCX-I ion beam accelerator. The 0.3 MeV, 30 mA K(+) beam from NDCX-I heats foil targets by combined longitudinal and transverse neutralized drift compression of the ion beam. Both the compressed and uncompressed parts of the NDCX-I beam heat targets. The exotic state of matter (WDM) in these experiments requires specialized diagnostic techniques. We have developed a target chamber and fielded target diagnostics including a fast multichannel optical pyrometer, optical streak camera, laser Doppler-shift interferometer (Velocity Interferometer System for Any Reflector), beam transmission diagnostics, and high-speed gated cameras. We also present plans and opportunities for diagnostic development and a new target chamber for NDCX-II.

  3. 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.

  4. Signatures of the Primordial Universe from Its Emptiness: Measurement of Baryon Acoustic Oscillations from Minima of the Density Field

    NASA Astrophysics Data System (ADS)

    Kitaura, Francisco-Shu; Chuang, Chia-Hsun; Liang, Yu; Zhao, Cheng; Tao, Charling; Rodríguez-Torres, Sergio; Eisenstein, Daniel J.; Gil-Marín, Héctor; Kneib, Jean-Paul; McBride, Cameron; Percival, Will J.; Ross, Ashley J.; Sánchez, Ariel G.; Tinker, Jeremy; Tojeiro, Rita; Vargas-Magana, Mariana; Zhao, Gong-Bo

    2016-04-01

    Sound waves from the primordial fluctuations of the Universe imprinted in the large-scale structure, called baryon acoustic oscillations (BAOs), can be used as standard rulers to measure the scale of the Universe. These oscillations have already been detected in the distribution of galaxies. Here we propose to measure BAOs from the troughs (minima) of the density field. Based on two sets of accurate mock halo catalogues with and without BAOs in the seed initial conditions, we demonstrate that the BAO signal cannot be obtained from the clustering of classical disjoint voids, but it is clearly detected from overlapping voids. The latter represent an estimate of all troughs of the density field. We compute them from the empty circumsphere centers constrained by tetrahedra of galaxies using Delaunay triangulation. Our theoretical models based on an unprecedented large set of detailed simulated void catalogues are remarkably well confirmed by observational data. We use the largest recently publicly available sample of luminous red galaxies from SDSS-III BOSS DR11 to unveil for the first time a >3 σ BAO detection from voids in observations. Since voids are nearly isotropically expanding regions, their centers represent the most quiet places in the Universe, keeping in mind the cosmos origin and providing a new promising window in the analysis of the cosmological large-scale structure from galaxy surveys.

  5. Signatures of the Primordial Universe from Its Emptiness: Measurement of Baryon Acoustic Oscillations from Minima of the Density Field.

    PubMed

    Kitaura, Francisco-Shu; Chuang, Chia-Hsun; Liang, Yu; Zhao, Cheng; Tao, Charling; Rodríguez-Torres, Sergio; Eisenstein, Daniel J; Gil-Marín, Héctor; Kneib, Jean-Paul; McBride, Cameron; Percival, Will J; Ross, Ashley J; Sánchez, Ariel G; Tinker, Jeremy; Tojeiro, Rita; Vargas-Magana, Mariana; Zhao, Gong-Bo

    2016-04-29

    Sound waves from the primordial fluctuations of the Universe imprinted in the large-scale structure, called baryon acoustic oscillations (BAOs), can be used as standard rulers to measure the scale of the Universe. These oscillations have already been detected in the distribution of galaxies. Here we propose to measure BAOs from the troughs (minima) of the density field. Based on two sets of accurate mock halo catalogues with and without BAOs in the seed initial conditions, we demonstrate that the BAO signal cannot be obtained from the clustering of classical disjoint voids, but it is clearly detected from overlapping voids. The latter represent an estimate of all troughs of the density field. We compute them from the empty circumsphere centers constrained by tetrahedra of galaxies using Delaunay triangulation. Our theoretical models based on an unprecedented large set of detailed simulated void catalogues are remarkably well confirmed by observational data. We use the largest recently publicly available sample of luminous red galaxies from SDSS-III BOSS DR11 to unveil for the first time a >3σ BAO detection from voids in observations. Since voids are nearly isotropically expanding regions, their centers represent the most quiet places in the Universe, keeping in mind the cosmos origin and providing a new promising window in the analysis of the cosmological large-scale structure from galaxy surveys.

  6. 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.

  7. 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.

  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. Energy Balanced Strategies for Maximizing the Lifetime of Sparsely Deployed Underwater Acoustic Sensor Networks

    PubMed Central

    Luo, Hanjiang; Guo, Zhongwen; Wu, Kaishun; Hong, Feng; Feng, Yuan

    2009-01-01

    Underwater acoustic sensor networks (UWA-SNs) are envisioned to perform monitoring tasks over the large portion of the world covered by oceans. Due to economics and the large area of the ocean, UWA-SNs are mainly sparsely deployed networks nowadays. The limited battery resources is a big challenge for the deployment of such long-term sensor networks. Unbalanced battery energy consumption will lead to early energy depletion of nodes, which partitions the whole networks and impairs the integrity of the monitoring datasets or even results in the collapse of the entire networks. On the contrary, balanced energy dissipation of nodes can prolong the lifetime of such networks. In this paper, we focus on the energy balance dissipation problem of two types of sparsely deployed UWA-SNs: underwater moored monitoring systems and sparsely deployed two-dimensional UWA-SNs. We first analyze the reasons of unbalanced energy consumption in such networks, then we propose two energy balanced strategies to maximize the lifetime of networks both in shallow and deep water. Finally, we evaluate our methods by simulations and the results show that the two strategies can achieve balanced energy consumption per node while at the same time prolong the networks lifetime. PMID:22399970

  10. Lightweight filter architecture for energy efficient mobile vehicle localization based on a distributed acoustic sensor network.

    PubMed

    Kim, Keonwook

    2013-08-23

    The generic properties of an acoustic signal provide numerous benefits for localization by applying energy-based methods over a deployed wireless sensor network (WSN). However, the signal generated by a stationary target utilizes a significant amount of bandwidth and power in the system without providing further position information. For vehicle localization, this paper proposes a novel proximity velocity vector estimator (PVVE) node architecture in order to capture the energy from a moving vehicle and reject the signal from motionless automobiles around the WSN node. A cascade structure between analog envelope detector and digital exponential smoothing filter presents the velocity vector-sensitive output with low analog circuit and digital computation complexity. The optimal parameters in the exponential smoothing filter are obtained by analytical and mathematical methods for maximum variation over the vehicle speed. For stationary targets, the derived simulation based on the acoustic field parameters demonstrates that the system significantly reduces the communication requirements with low complexity and can be expected to extend the operation time considerably.

  11. Lightweight Filter Architecture for Energy Efficient Mobile Vehicle Localization Based on a Distributed Acoustic Sensor Network

    PubMed Central

    Kim, Keonwook

    2013-01-01

    The generic properties of an acoustic signal provide numerous benefits for localization by applying energy-based methods over a deployed wireless sensor network (WSN). However, the signal generated by a stationary target utilizes a significant amount of bandwidth and power in the system without providing further position information. For vehicle localization, this paper proposes a novel proximity velocity vector estimator (PVVE) node architecture in order to capture the energy from a moving vehicle and reject the signal from motionless automobiles around the WSN node. A cascade structure between analog envelope detector and digital exponential smoothing filter presents the velocity vector-sensitive output with low analog circuit and digital computation complexity. The optimal parameters in the exponential smoothing filter are obtained by analytical and mathematical methods for maximum variation over the vehicle speed. For stationary targets, the derived simulation based on the acoustic field parameters demonstrates that the system significantly reduces the communication requirements with low complexity and can be expected to extend the operation time considerably. PMID:23979482

  12. High field tunneling as a limiting factor of maximum energy density in dielectric energy storage capacitors

    NASA Astrophysics Data System (ADS)

    Chen, Qin; Wang, Yong; Zhou, Xin; Zhang, Q. M.; Zhang, Shihai

    2008-04-01

    In several low loss dielectric materials, it was observed that the energy loss remains very small under low and medium electric fields but dramatically increases at high field which is believed to be due to tunneling current. The increase of tunneling current at high field is due to the decrease of barrier width and height and is a universal phenomenon in all dielectric materials. Due to the requirement of high energy efficiency, high field conduction places a limit for the maximum operation field, which could be lower than the breakdown field and act as the limiting factor of energy density.

  13. Generation of Gigabar Pressures for High-Energy-Density Plasmas

    NASA Astrophysics Data System (ADS)

    Theobald, W.; Betti, R.; Bose, A.; Seka, W.; Stoeckl, C.; Mangino, D.; Casner, A.; Beg, F. N.; Llor Aisa, E.; Ribeyre, X.; Wei, M. S.; Schoff, M. E.; Florido, R.; Mancini, R. C.

    2016-10-01

    Experiments on the OMEGA laser were performed to study gigabar pressures in small (50- μm-diam) Ti and Cu target samples for high-energy-density plasma applications. The samples were precisely placed (better than 10 μm) at the center of a spherical plastic matrix that is irradiated at incident laser intensities of 5 ×1015 W /cm2 . The laser launches a spherical shock wave that converges in the center in order to reach Gbar pressures in the sample. The shock convergence produces a short burst ( 30ps) of x-ray emission. Time-resolved and time-integrated x-ray spectroscopy provides the means to diagnose the plasma conditions in the sample. The time-resolved spectra are compared to predictions from radiation-hydrodynamic simulations to infer the material conditions at Gbar pressures. A second x-ray flash delayed by 600ps caused by the breakout of the rebounded shock through the outer surface of the compressed plastic was observed. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0001944 and by the Fusion Science Center under Grant No. DE-FC02-04ER54789.

  14. 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.

  15. Effects of thermal treatment on energy density and hardness of torrefied wood pellets

    SciTech Connect

    Peng, Jianghong; Wang, Jingsong; Bi, Xiaotao T.; Lim, C. Jim; Sokhansanj, Shahab; Peng, Hanchao; Jia, Dening

    2014-09-27

    Here, three types of wood pellets samples, including two types of commercial pellets and one type of lab-made control pellets were torrefied in a fixed bed unit to study the effect of thermal pretreatment on the quality of wood pellets. The quality of wood pellets was mainly characterized by the pellet density, bulk density, higher heating value, Meyer hardness, saturated moisture uptake, volumetric energy density, and energy yield. Results showed that torrefaction significantly decreased the pellet density, hardness, volumetric energy density, and energy yield. The higher heating value increased and the saturated moisture content decreased after torrefaction. In view of the lower density, lower hardness, lower volumetric energy density, and energy yield of torrefied pellets, it is recommended that biomass should be torrefied and then compressed to make strong pellets of high hydrophobicity and volumetric energy density.

  16. Effects of thermal treatment on energy density and hardness of torrefied wood pellets

    DOE PAGES

    Peng, Jianghong; Wang, Jingsong; Bi, Xiaotao T.; ...

    2014-09-27

    Here, three types of wood pellets samples, including two types of commercial pellets and one type of lab-made control pellets were torrefied in a fixed bed unit to study the effect of thermal pretreatment on the quality of wood pellets. The quality of wood pellets was mainly characterized by the pellet density, bulk density, higher heating value, Meyer hardness, saturated moisture uptake, volumetric energy density, and energy yield. Results showed that torrefaction significantly decreased the pellet density, hardness, volumetric energy density, and energy yield. The higher heating value increased and the saturated moisture content decreased after torrefaction. In view ofmore » the lower density, lower hardness, lower volumetric energy density, and energy yield of torrefied pellets, it is recommended that biomass should be torrefied and then compressed to make strong pellets of high hydrophobicity and volumetric energy density.« less

  17. Acoustic dose and acoustic dose-rate.

    PubMed

    Duck, Francis

    2009-10-01

    Acoustic dose is defined as the energy deposited by absorption of an acoustic wave per unit mass of the medium supporting the wave. Expressions for acoustic dose and acoustic dose-rate are given for plane-wave conditions, including temporal and frequency dependencies of energy deposition. The relationship between the acoustic dose-rate and the resulting temperature increase is explored, as is the relationship between acoustic dose-rate and radiation force. Energy transfer from the wave to the medium by means of acoustic cavitation is considered, and an approach is proposed in principle that could allow cavitation to be included within the proposed definitions of acoustic dose and acoustic dose-rate.

  18. Contactless ultrasonic energy transfer for wireless systems: acoustic-piezoelectric structure interaction modeling and performance enhancement

    NASA Astrophysics Data System (ADS)

    Shahab, S.; Erturk, A.

    2014-12-01

    There are several applications of wireless electronic components with little or no ambient energy available to harvest, yet wireless battery charging for such systems is still of great interest. Example applications range from biomedical implants to sensors located in hazardous environments. Energy transfer based on the propagation of acoustic waves at ultrasonic frequencies is a recently explored alternative that offers increased transmitter-receiver distance, reduced loss and the elimination of electromagnetic fields. As this research area receives growing attention, there is an increased need for fully coupled model development to quantify the energy transfer characteristics, with a focus on the transmitter, receiver, medium, geometric and material parameters. We present multiphysics modeling and case studies of the contactless ultrasonic energy transfer for wireless electronic components submerged in fluid. The source is a pulsating sphere, and the receiver is a piezoelectric bar operating in the 33-mode of piezoelectricity with a fundamental resonance frequency above the audible frequency range. The goal is to quantify the electrical power delivered to the load (connected to the receiver) in terms of the source strength. Both the analytical and finite element models have been developed for the resulting acoustic-piezoelectric structure interaction problem. Resistive and resistive-inductive electrical loading cases are presented, and optimality conditions are discussed. Broadband power transfer is achieved by optimal resistive-reactive load tuning for performance enhancement and frequency-wise robustness. Significant enhancement of the power output is reported due to the use of a hard piezoelectric receiver (PZT-8) instead of a soft counterpart (PZT-5H) as a result of reduced material damping. The analytical multiphysics modeling approach given in this work can be used to predict and optimize the coupled system dynamics with very good accuracy and dramatically

  19. The Effectiveness of the Aquaflex Gel Pad in the Transmission of Acoustic Energy

    PubMed Central

    Klucinec, Brian

    1996-01-01

    Objective: The purpose of this study was to assess the effectiveness of the Aquaflex Gel Pad in the transmission of acoustic energy. Design and Setting: This was a comparative study that utilized descriptive statistics for result interpretation. The independent variables included ultrasound intensity, interposed materials, and trials. The dependent variable was peak-to-peak voltage output recorded via an oscilloscope. The study was conducted in a ventilated research laboratory. Measurements: Three trials were conducted with six combinations of material interposed between a conducting (1 MHz) and a receiving sound head. The interposed materials were as follows: 1) ultrasound gel, 2) gel plus a gel pad, 3) gel plus a gel pad and pig tissue sample (0.90 cm of subcutaneous fat), 4) gel plus a gel pad and a pig tissue sample (1.8 cm of subcutaneous fat), 5) gel plus thin pig tissue sample, and 6) gel plus thick pig tissue sample. Each interposed material combination was tested at the intensities (W/cm2) as follows: 0.10, 0.25, 0.50, 1.00, 1.50, and 2.50. Results: The gel pad proved to be an efficient couplant in the delivery of high-frequency acoustic energy. Using ultrasound gel as the base line (100% transmissivity) it was concluded that the gel pad transmitted more acoustic energy at every intensity except at 0.1 W/cm2. The gel pad used with the two thicknesses of subcutaneous fat gave comparable results. Gel used with the two thicknesses of subcutaneous fat yielded results that warrant further investigation. Conclusions: I believe gel pads are a practical choice for clinical applications of ultrasound over uneven surfaces. The reusable gel pads offer the clinician a convenient and reliable method for delivering ultrasound energy to the patient. I believe it is preferable to use the gel pad with ultrasound gel directly applied to the patient and at the sound head-gel pad interface as opposed to using the traditional water bath immersion method. ImagesFig 1. PMID

  20. Envelope Solitons in Acoustically Dispersive Vitreous Silica

    NASA Technical Reports Server (NTRS)

    Cantrell, John H.; Yost, William T.

    2012-01-01

    Acoustic radiation-induced static strains, displacements, and stresses are manifested as rectified or dc waveforms linked to the energy density of an acoustic wave or vibrational mode via the mode nonlinearity parameter of the material. An analytical model is developed for acoustically dispersive media that predicts the evolution of the energy density of an initial waveform into a series of energy solitons that generates a corresponding series of radiation-induced static strains (envelope solitons). The evolutionary characteristics of the envelope solitons are confirmed experimentally in Suprasil W1 vitreous silica. The value (-11.9 plus or minus 1.43) for the nonlinearity parameter, determined from displacement measurements of the envelope solitons via a capacitive transducer, is in good agreement with the value (-11.6 plus or minus 1.16) obtained independently from acoustic harmonic generation measurements. The agreement provides strong, quantitative evidence for the validity of the model.

  1. 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

  2. Time-Dependent Dark Energy Density and Holographic DE Model with Interaction

    NASA Astrophysics Data System (ADS)

    Saadat, H.; Saadat, A. M.

    2011-05-01

    In this article we consider holographic dark energy model with interaction and space curvature. We calculate cosmic scale factor by using the time-dependent dark energy density. Then we obtain phenomenological interaction between holographic dark energy and matter.

  3. Gravimetric and density profiling using the combination of surface acoustic waves and neutron reflectivity.

    PubMed

    Toolan, Daniel T W; Barker, Robert; Gough, Tim; Topham, Paul D; Howse, Jonathan R; Glidle, Andrew

    2017-02-01

    A new approach is described herein, where neutron reflectivity measurements that probe changes in the density profile of thin films as they absorb material from the gas phase have been combined with a Love wave based gravimetric assay that measures the mass of absorbed material. This combination of techniques not only determines the spatial distribution of absorbed molecules, but also reveals the amount of void space within the thin film (a quantity that can be difficult to assess using neutron reflectivity measurements alone). The uptake of organic solvent vapours into spun cast films of polystyrene has been used as a model system with a view to this method having the potential for extension to the study of other systems. These could include, for example, humidity sensors, hydrogel swelling, biomolecule adsorption or transformations of electroactive and chemically reactive thin films. This is the first ever demonstration of combined neutron reflectivity and Love wave-based gravimetry and the experimental caveats, limitations and scope of the method are explored and discussed in detail.

  4. Investigation of the Acoustic Source Characteristics of High Energy Laser Pulses: Models and Experiment

    DTIC Science & Technology

    2008-06-01

    consistent with the expected approximately 1/r relationship for pressure amplitudes under 100MPa. The modeling effort employed AUTODYN , a finite...agreed with Vogel’s measured values. The efficiency, pulse length, pulse shape, and variation of pressure amplitude with range achieved with AUTODYN ...Nonlinear Acoustics, AUTODYN , Acoustic Modeling, Shock Acoustics 16. PRICE CODE 17. SECURITY CLASSIFICATION OF REPORT Unclassified 18. SECURITY

  5. Improving Robotic Assembly of Planar High Energy Density Targets

    NASA Astrophysics Data System (ADS)

    Dudt, D.; Carlson, L.; Alexander, N.; Boehm, K.

    2016-10-01

    Increased quantities of planar assemblies for high energy density targets are needed with higher shot rates being implemented at facilities such as the National Ignition Facility and the Matter in Extreme Conditions station of the Linac Coherent Light Source. To meet this growing demand, robotics are used to reduce assembly time. This project studies how machine vision and force feedback systems can be used to improve the quantity and quality of planar target assemblies. Vision-guided robotics can identify and locate parts, reducing laborious manual loading of parts into precision pallets and associated teaching of locations. On-board automated inspection can measure part pickup offsets to correct part drop-off placement into target assemblies. Force feedback systems can detect pickup locations and apply consistent force to produce more uniform glue bond thickness, thus improving the performance of the targets. System designs and performance evaluations will be presented. Work supported in part by the US DOE under the Science Undergraduate Laboratory Internships Program (SULI) and ICF Target Fabrication DE-NA0001808.

  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. 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.

  8. 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.

  9. Ion energy distributions and densities in the plume of Enceladus

    NASA Astrophysics Data System (ADS)

    Sakai, Shotaro; Cravens, Thomas E.; Omidi, Nojan; Perry, Mark E.; Waite, J. Hunter

    2016-10-01

    Enceladus has a dynamic plume that is emitting gas, including water vapor, and dust. The gas is ionized by solar EUV radiation, charge exchange, and electron impact and extends throughout the inner magnetosphere of Saturn. The charge exchange collisions alter the plasma composition. Ice grains (dust) escape from the vicinity of Enceladus and form the E ring, including a portion that is negatively charged by the local plasma. The inner magnetosphere within 10 RS (Saturn radii) contains a complex mixture of plasma, neutral gas, and dust that links back to Enceladus. In this paper we investigate the energy distributions, ion species and densities of water group ions in the plume of Enceladus using test particle and Monte Carlo methods that include collisional processes such as charge exchange and ion-neutral chemical reactions. Ion observations from the Cassini Ion and Neutral Mass Spectrometer (INMS) for E07 are presented for the first time. We use the modeling results to interpret observations made by the Cassini Plasma Spectrometer (CAPS) and the INMS. The low energy ions, as observed by CAPS, appear to be affected by a vertical electric field (EZ=-10 μV/m) in the plume. The EZ field may be associated with the charged dust and/or the pressure gradient of plasma. The model results, along with the results of earlier models, show that H3O+ ions created by chemistry are predominant in the plume, which agrees with INMS and CAPS data, but the INMS count rate in the plume for the model is several times greater than the data, which we do not fully understand. This composition and the total ion count found in the plume agree with INMS and CAPS data. On the other hand, the Cassini Langmuir Probe measured a maximum plume ion density more than 30,000 cm-3, which is far larger than the maximum ion density from our model, 900 cm-3. The model results also demonstrate that most of the ions in the plume are from the external magnetospheric flow and are not generated by local

  10. Vibro-acoustic modelling of aircraft double-walls with structural links using Statistical Energy Analysis

    NASA Astrophysics Data System (ADS)

    Campolina, Bruno L.

    The prediction of aircraft interior noise involves the vibroacoustic modelling of the fuselage with noise control treatments. This structure is composed of a stiffened metallic or composite panel, lined with a thermal and acoustic insulation layer (glass wool), and structurally connected via vibration isolators to a commercial lining panel (trim). The goal of this work aims at tailoring the noise control treatments taking design constraints such as weight and space optimization into account. For this purpose, a representative aircraft double-wall is modelled using the Statistical Energy Analysis (SEA) method. Laboratory excitations such as diffuse acoustic field and point force are addressed and trends are derived for applications under in-flight conditions, considering turbulent boundary layer excitation. The effect of the porous layer compression is firstly addressed. In aeronautical applications, compression can result from the installation of equipment and cables. It is studied analytically and experimentally, using a single panel and a fibrous uniformly compressed over 100% of its surface. When compression increases, a degradation of the transmission loss up to 5 dB for a 50% compression of the porous thickness is observed mainly in the mid-frequency range (around 800 Hz). However, for realistic cases, the effect should be reduced since the compression rate is lower and compression occurs locally. Then the transmission through structural connections between panels is addressed using a four-pole approach that links the force-velocity pair at each side of the connection. The modelling integrates experimental dynamic stiffness of isolators, derived using an adapted test rig. The structural transmission is then experimentally validated and included in the double-wall SEA model as an equivalent coupling loss factor (CLF) between panels. The tested structures being flat, only axial transmission is addressed. Finally, the dominant sound transmission paths are

  11. Growth and optimization of piezoelectric single crystal transducers for energy harvesting from acoustic sources

    NASA Astrophysics Data System (ADS)

    Dhar, Romit

    Low power requirements of modern sensors and electronics have led to the examination of the feasibility of several energy harvesting schemes. This thesis describes the fabrication and performance of an acoustic energy harvester with single crystal piezoelectric unimorph. The unimorphs were fabricated from single crystal relaxor ferroelectric (1-x)PMN - xPT grown with x = 0.3 and 0.32 as the starting composition. It is demonstrated that significant power can be harvested using unimorph structures from an acoustic field at resonance. Passive circuit components were used for output circuit with a resistive load in series with a tunable inductor. A tuning capacitor connected in parallel to the device further increased the power output by matching the impedance of the unimorph. The power harvested can be either used directly for running low-power devices or can be stored in a rechargeable battery. A comparison of the performance of PMN-PT and PZT unimorphs at the resonance of the coupled structure under identical excitation conditions was done. For a certain optimized thickness ratio and circuit parameters, the single crystal PMN-PT unimorph generated 30 mW of power while a PZT unimorph generated 7.5 mW at resonance and room temperature. The harvested output power from the single crystal PMN-PT unimorphs depends on several material properties, physical and ambient parameters and an effort has been made to study their effect on the performance. A self-seeding high pressure Bridgman (HPB) technique was used to grow the PMN-PT single crystal ingots in a cost-effective way in our laboratories. Several techniques of material processing were developed to fabricate the PMN-PT single crystal unimorphs from as grown bulk ingots. This growth technique produced good quality single crystals for our experiments, with a k33 = 0.91 for a <001> oriented bar.

  12. Method and apparatus for sizing and separating warp yarns using acoustical energy

    DOEpatents

    Sheen, Shuh-Haw; Chien, Hual-Te; Raptis, Apostolos C.; Kupperman, David S.

    1998-01-01

    A slashing process for preparing warp yarns for weaving operations including the steps of sizing and/or desizing the yarns in an acoustic resonance box and separating the yarns with a leasing apparatus comprised of a set of acoustically agitated lease rods. The sizing step includes immersing the yarns in a size solution contained in an acoustic resonance box. Acoustic transducers are positioned against the exterior of the box for generating an acoustic pressure field within the size solution. Ultrasonic waves that result from the acoustic pressure field continuously agitate the size solution to effect greater mixing and more uniform application and penetration of the size onto the yarns. The sized yarns are then separated by passing the warp yarns over and under lease rods. Electroacoustic transducers generate acoustic waves along the longitudinal axis of the lease rods, creating a shearing motion on the surface of the rods for splitting the yarns.

  13. Method and apparatus for sizing and separating warp yarns using acoustical energy

    DOEpatents

    Sheen, S.H.; Chien, H.T.; Raptis, A.C.; Kupperman, D.S.

    1998-05-19

    A slashing process is disclosed for preparing warp yarns for weaving operations including the steps of sizing and/or desizing the yarns in an acoustic resonance box and separating the yarns with a leasing apparatus comprised of a set of acoustically agitated lease rods. The sizing step includes immersing the yarns in a size solution contained in an acoustic resonance box. Acoustic transducers are positioned against the exterior of the box for generating an acoustic pressure field within the size solution. Ultrasonic waves that result from the acoustic pressure field continuously agitate the size solution to effect greater mixing and more uniform application and penetration of the size onto the yarns. The sized yarns are then separated by passing the warp yarns over and under lease rods. Electroacoustic transducers generate acoustic waves along the longitudinal axis of the lease rods, creating a shearing motion on the surface of the rods for splitting the yarns. 2 figs.

  14. 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.

  15. Distance, Growth Factor, and Dark Energy Constraints from Photometric Baryon Acoustic Oscillation and Weak Lensing Measurements

    NASA Astrophysics Data System (ADS)

    Zhan, Hu; Knox, Lloyd; Tyson, J. Anthony

    2009-01-01

    Baryon acoustic oscillations (BAOs) and weak lensing (WL) are complementary probes of cosmology. We explore the distance and growth factor measurements from photometric BAO and WL techniques, and investigate the roles of the distance and growth factor in constraining dark energy. We find for WL that the growth factor has a great impact on dark energy constraints, but is much less powerful than the distance. Dark energy constraints from WL are concentrated in considerably fewer distance eigenmodes than those from BAO, with the largest contributions from modes that are sensitive to the absolute distance. Both techniques have some well-determined distance eigenmodes that are not very sensitive to the dark energy equation-of-state parameters w0 and wa, suggesting that they can accommodate additional parameters for dark energy and for the control of systematic uncertainties. A joint analysis of BAO and WL is far more powerful than either technique alone, and the resulting constraints on the distance and growth factor will be useful for distinguishing dark energy and modified gravity models. The Large Synoptic Survey Telescope (LSST) will yield both WL and angular BAO over a sample of several billion galaxies. Joint LSST BAO and WL can yield 0.5% level precision on ten comoving distances evenly spaced in log(1 + z) between redshift 0.3 and 3 with cosmic microwave background priors from Planck. In addition, since the angular diameter distance, which directly affects the observables, is linked to the comoving distance solely by the curvature radius in the Friedmann-Robertson-Walker metric solution, the LSST can achieve a pure metric constraint of 0.017 on the mean curvature parameter Ω k of the universe simultaneously with the constraints on the comoving distances.

  16. Determining the energy level of laser induced cracks in alumina substrate via acoustic emission

    NASA Astrophysics Data System (ADS)

    Aslan, M.; Beausang, J.; Tittmann, B. R.

    2000-05-01

    The electronics industry relies on alumina (Al2O3) substrates to isolate, electrically and thermally, the computer chip from the rest of the circuit. In order to improve the manufacturing process of these chips, it is desirable to machine the substrates with a laser rather than the conventional techniques. Unfortunately, the high thermal stresses due to the intensity of the laser cause the extremely brittle ceramic to crack and sometimes fail. The purpose of this research was to study the response of a thin alumina ceramic substrate while it was slowly drilled with a CO2 laser. The energy released by the cracks were measured in-situ via acoustic emission (AE). AE is ideal for capturing the stress wave emissions emitted from the cracking events, while the ceramic is being drilled with the laser. One of the components of the AE system, the Digital Wave Fracture Wave Detector™, recorded the AE signals emitted during slow laser drilling of the alumina plates. Total crack length was correlated with total AE energy emitted, and these data were compared in two experiments, slow drilling and crack extension. A fundamental trend of increasing AE energy with increasing crack length was verified in these experiments.—This work has been partially supported by National Science Foundation Grant #CMS-9634744.

  17. TEMPO-based catholyte for high-energy density nonaqueous redox flow batteries.

    PubMed

    Wei, Xiaoliang; Xu, Wu; Vijayakumar, Murugesan; Cosimbescu, Lelia; Liu, Tianbiao; Sprenkle, Vincent; Wang, Wei

    2014-12-03

    A TEMPO-based non-aqueous electrolyte with the TEMPO concentration as high as 2.0 m is demonstrated as a high-energy-density catholyte for redox flow battery applications. With a hybrid anode, Li|TEMPO flow cells using this electrolyte deliver an energy efficiency of ca. 70% and an impressively high energy density of 126 W h L(-1) .

  18. 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.

  19. Broadband Acoustic Environment at a Tidal Energy Site in Puget Sound

    SciTech Connect

    Xu, Jinshan; Deng, Zhiqun; Martinez, Jayson J.; Carlson, Thomas J.; Myers, Joshua R.; Weiland, Mark A.

    2012-04-04

    Admiralty Inlet has been selected as a potential tidal energy site. It is located near shipping lanes, is a highly variable acoustic environment, and is frequented by the endangered southern resident killer whale (SRKW). Resolving environmental impacts is the first step to receiving approval to deploy tidal turbines. Several monitoring technologies are being considered to determine the presence of SRKW near the turbines. Broadband noise level measurements are critical for determining design and operational specifications of these technologies. Acoustic environment data at the proposed site was acquired at different depths using a cabled vertical line array from three different cruises during high tidal period in February, May, and June 2011. The ambient noise level decreases approximately 25 dB re 1 μPa per octave from frequency ranges of 1 kHz to 70 kHz, and increases approximately 20 dB re 1 μPa per octave for the frequency from 70 kHz to 200 kHz. The difference of noise pressure levels in different months varies from 10 to 30 dB re 1 μPa for the frequency range below 70 kHz. Commercial shipping and ferry vessel traffic were found to be the most significant contributors to sound pressure levels for the frequency range from 100 Hz to 70 kHz, and the variation could be as high as 30 dB re 1 μPa. These noise level measurements provide the basic information for designing and evaluating both active and passive monitoring systems proposed for deploying and operating for tidal power generation alert system.

  20. Enhancement of the maximum energy density in atomic layer deposited oxide based thin film capacitors

    NASA Astrophysics Data System (ADS)

    Spahr, Holger; Nowak, Christine; Hirschberg, Felix; Reinker, Johannes; Kowalsky, Wolfgang; Hente, Dirk; Johannes, Hans-Hermann

    2013-07-01

    Thin film capacitors on areas up to 6 mm2 have been measured regarding capacitance density, relative permittivity, and electrical breakdown. The maximum storable energy density of the thin film capacitors will be discussed as a parameter to evaluate the thin film capacitors applicability. Therefore the measurements of the layer thickness, capacitance density, and the breakdown voltage were combined to achieve the maximum storable areal and volume energy density depending on the dielectric layer thickness. Thickness dependent volume energy densities of up to 50 J/cm3 for pure Al2O3 and 60 J/cm3 for Al2O3/TiO2 nanolaminates were reached.

  1. Acoustic Monitoring of Beluga Whale Interactions with Cook Inlet Tidal Energy Project

    SciTech Connect

    Worthington, Monty

    2014-02-05

    Cook Inlet, Alaska is home to some of the greatest tidal energy resources in the U.S., as well as an endangered population of beluga whales (Delphinapterus leucas). Successfully permitting and operating a tidal power project in Cook Inlet requires a biological assessment of the potential and realized effects of the physical presence and sound footprint of tidal turbines on the distribution, relative abundance, and behavior of Cook Inlet beluga whales. ORPC Alaska, working with the Project Team—LGL Alaska Research Associates, University of Alaska Anchorage, TerraSond, and Greeneridge Science—undertook the following U.S. Department of Energy (DOE) study to characterize beluga whales in Cook Inlet – Acoustic Monitoring of Beluga Whale Interactions with the Cook Inlet Tidal Energy Project (Project). ORPC Alaska, LLC, is a wholly-owned subsidiary of Ocean Renewable Power Company, LLC, (collectively, ORPC). ORPC is a global leader in the development of hydrokinetic power systems and eco-conscious projects that harness the power of ocean and river currents to create clean, predictable renewable energy. ORPC is developing a tidal energy demonstration project in Cook Inlet at East Foreland where ORPC has a Federal Energy Regulatory Commission (FERC) preliminary permit (P-13821). The Project collected baseline data to characterize pre-deployment patterns of marine mammal distribution, relative abundance, and behavior in ORPC’s proposed deployment area at East Foreland. ORPC also completed work near Fire Island where ORPC held a FERC preliminary permit (P-12679) until March 6, 2013. Passive hydroacoustic devices (previously utilized with bowhead whales in the Beaufort Sea) were adapted for study of beluga whales to determine the relative abundance of beluga whale vocalizations within the proposed deployment areas. Hydroacoustic data collected during the Project were used to characterize the ambient acoustic environment of the project site pre-deployment to inform the

  2. Effects of nonthermal distribution of electrons and polarity of net dust-charge number density on nonplanar dust-ion-acoustic solitary waves.

    PubMed

    Mamun, A A; Shukla, P K

    2009-09-01

    Effects of the nonthermal distribution of electrons as well as the polarity of the net dust-charge number density on nonplanar (viz. cylindrical and spherical) dust-ion-acoustic solitary waves (DIASWs) are investigated by employing the reductive perturbation method. It is found that the basic features of the DIASWs are significantly modified by the effects of nonthermal electron distribution, polarity of net dust-charge number density, and nonplanar geometry. The implications of our results in some space and laboratory dusty plasma environments are briefly discussed.

  3. Can seismic (destructive) energy be stored after conversion into useful electrical or acoustic energy?

    NASA Astrophysics Data System (ADS)

    Verma, Umesh P.; Sinha, Madhurendra N.

    2014-06-01

    Since the dawn of precursory revolution in the seismology and electromagnetic radiation platform., F.T. Freund (2010) et.al, have used piezoelectric effect on the crustal geo-materials and emanation of seismic pre signals frequently. Their effect in form of ULF and VHF are commonly detected (by Greece and American seismologists)in the upper ionosphere from surface of globe. TEC, OLR. MMC are the consequent instrumentation in acquiring data to these pre-earthquake signals. Our attempt is to detect the signals prior to earthquake due to impending stress in the area and store the spreading destructive energy to electrical voltage applying the mathematics of piezoelectric equations and algebra. Energy released during seismic eruption is in the range of 10 13 to 1018 Joule for each event of 6 to 8 Mw. Spread and propagation of energy follows the Maxwell theory of wave equation and fundamental law of electricity and electromagnetism. Stress accumulated within the crustal block is triggered into bringing about geophysical and geochemical changes within the reservoir rocks interacting stress. Study made by pioneers in the seismic precursory development states generation of charge and coronal discharge prior seismicity within the rocks under stress. This is consequence to admixing of positive charge developed at unstressed volume and negative at stressed sub volume of rocks1 [F.T.Freidemann2010]. Ionosphere proturbance in form of ULF, ELF, ELS and EQL, EQS are the projected consequence of electromagnetic wave propagation 2 [10,11,15 ] Harnessing of electrical components from the energy propagated due to stress inducing EM waves is the aim of paper. Electrical discharge prior to seismicity within geo-materials is established phenomena which can be calibrated with the piezoelectric sensors application implanted for detection and harnessing the signals. These prior signals induced in form of electromagnetic response are felicitated into being converted into electrical energy

  4. 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.

  5. Isotope Generated Electron Density in Silicon Carbide Direct Energy Converters

    DTIC Science & Technology

    2006-10-01

    output of a diode into a resistively loaded circuit. This paper describes the use of a nuclear scattering code ( MCNPX ) to calculate the increased...used in the MCNPX calculations . The range constant supplied in section 3.2 (9) must be multiplied by the density of the material used. The density... MCNPX code. Instead, we are only modeling the SiC material and attempting to calculate how many free-electrons are being generated within as a

  6. Role of the density, density effect and mean excitation energy in solid-state detectors for small photon fields.

    PubMed

    Andreo, Pedro; Benmakhlouf, Hamza

    2017-02-21

    A number of recent publications on small photon beam dosimetry aim at contributing to the understanding of the response of solid-state detectors in small fields. Some of them assign the difference in response to the mass density, or to the electron density, of the sensitive detector material relative to that of water. This work analyses the role of the mass and electron density ([Formula: see text]), density effect (δ) and mean excitation energy (I-value) of some detector materials in a 6 MV photon beam of 0.5 cm radius, its rationale being that the response of a detector depends critically on the stopping-power ratio detector-to-water. The influence on the detector response of volume scaling by electron density, and of electron single and multiple scattering, is also investigated. Detector materials are water, diamond and silicon, and additional materials are included for consistency in the analysis. A detailed analysis on the ([Formula: see text]) dependence of stopping-power ratios shows that the density effect δ depends both on the electron density and on the I-value of the medium, but not on the mass density ρ alone as is usually assumed. This leads to a double dependence of stopping-power ratios on the I-value and questions the adequacy of a 'density perturbation factor' or of common interpretations of detector response in terms of ρ alone. Differences in response can be described in terms of the variation of stopping power ratios detector-to-water, mainly due to different I-values and to a lesser extent to different values of electron density. It is found that at low energies the trend of Monte Carlo-calculated electron fluence spectra inside the detector materials depends solely on their I-values. No dependence on mass density or density effect alone is observed at any energy. The trend of restricted-cema ratios to water (as a substitute of absorbed dose ratios) follows that of stopping-power ratios at 1 MeV, the most probable energy of differential

  7. High-Efficiency Photovoltaic Energy Conversion using Surface Acoustic Waves in Piezoelectric Semiconductors

    NASA Astrophysics Data System (ADS)

    Yakovenko, Victor

    2010-03-01

    We propose a radically new design for photovoltaic energy conversion using surface acoustic waves (SAWs) in piezoelectric semiconductors. The periodically modulated electric field from SAW spatially separates photogenerated electrons and holes to the maxima and minima of SAW, thus preventing their recombination. The segregated electrons and holes are transported by the moving SAW to the collecting electrodes of two types, which produce dc electric output. Recent experiments [1] using SAWs in GaAs have demonstrated the photon to current conversion efficiency of 85%. These experiments were designed for photon counting, but we propose to adapt these techniques for highly efficient photovoltaic energy conversion. The advantages are that the electron-hole segregation takes place in the whole volume where SAW is present, and the electrons and holes are transported in the organized, collective manner at high speed, as opposed to random diffusion in conventional devices.[4pt] [1] S. J. Jiao, P. D. Batista, K. Biermann, R. Hey, and P. V. Santos, J. Appl. Phys. 106, 053708 (2009).

  8. 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.

  9. 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.

  10. 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

  11. 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.

  12. A universal method to calculate the surface energy density of spherical surfaces in crystals

    NASA Astrophysics Data System (ADS)

    Wang, Jian; Bian, Jianjun; Niu, Xinrui; Wang, Gangfeng

    2017-02-01

    Surface energy plays an important role in the mechanical performance of nanomaterials; however, determining the surface energy density of curved surfaces remains a challenge. In this paper, we conduct atomic simulations to calculate the surface energy density of spherical surfaces in various crystalline metals. It is found that the average surface energy density of spherical surfaces remains almost constant once its radius exceeds 5 nm. Then, using a geometrical analysis and the scaling law, we develop an analytical approach to estimate the surface energy density of spherical surfaces through that of planar surfaces. The theoretical prediction agrees well with the direct atomic simulations, and thus provides a simple and general method to calculate the surface energy density in crystals.

  13. 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.

  14. 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.

  15. MODEL-INDEPENDENT EVIDENCE FOR DARK ENERGY EVOLUTION FROM BARYON ACOUSTIC OSCILLATIONS

    SciTech Connect

    Sahni, V.; Shafieloo, A.; Starobinsky, A. A. E-mail: arman@apctp.org

    2014-10-01

    Baryon acoustic oscillations (BAOs) allow us to determine the expansion history of the universe, thereby shedding light on the nature of dark energy. Recent observations of BAOs in the Sloan Digital Sky Survey (SDSS) DR9 and DR11 have provided us with statistically independent measurements of H(z) at redshifts of 0.57 and 2.34, respectively. We show that these measurements can be used to test the cosmological constant hypothesis in a model-independent manner by means of an improved version of the Om diagnostic. Our results indicate that the SDSS DR11 measurement of H(z) = 222 ± 7 km s{sup –1} Mpc{sup –1} at z = 2.34, when taken in tandem with measurements of H(z) at lower redshifts, imply considerable tension with the standard ΛCDM model. Our estimation of the new diagnostic Omh {sup 2} from SDSS DR9 and DR11 data, namely, Omh {sup 2} ≈ 0.122 ± 0.01, which is equivalent to Ω{sub 0m} h {sup 2} for the spatially flat ΛCDM model, is in tension with the value Ω{sub 0m} h {sup 2} = 0.1426 ± 0.0025 determined for ΛCDM from Planck+WP. This tension is alleviated in models in which the cosmological constant was dynamically screened (compensated) in the past. Such evolving dark energy models display a pole in the effective equation of state of dark energy at high redshifts, which emerges as a smoking gun test for these theories.

  16. Model-independent Evidence for Dark Energy Evolution from Baryon Acoustic Oscillations

    NASA Astrophysics Data System (ADS)

    Sahni, V.; Shafieloo, A.; Starobinsky, A. A.

    2014-10-01

    Baryon acoustic oscillations (BAOs) allow us to determine the expansion history of the universe, thereby shedding light on the nature of dark energy. Recent observations of BAOs in the Sloan Digital Sky Survey (SDSS) DR9 and DR11 have provided us with statistically independent measurements of H(z) at redshifts of 0.57 and 2.34, respectively. We show that these measurements can be used to test the cosmological constant hypothesis in a model-independent manner by means of an improved version of the Om diagnostic. Our results indicate that the SDSS DR11 measurement of H(z) = 222 ± 7 km s-1 Mpc-1 at z = 2.34, when taken in tandem with measurements of H(z) at lower redshifts, imply considerable tension with the standard ΛCDM model. Our estimation of the new diagnostic Omh 2 from SDSS DR9 and DR11 data, namely, Omh 2 ≈ 0.122 ± 0.01, which is equivalent to Ω0m h 2 for the spatially flat ΛCDM model, is in tension with the value Ω0m h 2 = 0.1426 ± 0.0025 determined for ΛCDM from Planck+WP. This tension is alleviated in models in which the cosmological constant was dynamically screened (compensated) in the past. Such evolving dark energy models display a pole in the effective equation of state of dark energy at high redshifts, which emerges as a smoking gun test for these theories.

  17. Effects of Non-Homogeneities on the Eigenmodes of Acoustic Pressure in Combustion Chambers

    NASA Astrophysics Data System (ADS)

    Kim, J. S.; Williams, F. A.

    1998-02-01

    Modifications to acoustic eigenmodes in combustion chambers such as those of liquid propellant rocket engines, produced by spatial variations of density and sound speed that arise mainly through progress of combustion processes, are analyzed by using a variational method. The variational principle shows that the eigenvalue is the ratio of a weighted acoustic kinetic energy to a weighted acoustic potential energy, and the eigenfunction is the minimizing function of this ratio. A sample calculation is made for the case in which variations of the properties occur dominantly in the longitudinal direction, with lower temperatures and higher densities prevailing near the injector. The results of the calculation exhibit two major characteristics: the longitudinal density variation aids transfer of acoustic kinetic energy from a lower mode to the adjacent higher mode, so that the pure transverse modes have substantially larger reductions (sometimes exceeding 50%) of their eigenvalues than the combined modes; and variations of the acoustic pressure gradients are found to be larger in high-density regions, so that the acoustic pressure amplitude for purely tangential modes is found to be much higher near the injector than near the nozzle. The higher head acoustic pressure may contribute to the greater sensitivity of acoustic instability to characteristics of the flames near the injectors, as commonly found in engine tests. The improved acoustic eigensolutions can also be helpful in sizing damping devices, such as baffles or acoustic liners.

  18. Energy density functional analysis of shape coexistence in {sup 44}S

    SciTech Connect

    Li, Z. P.; Yao, J. M.; Vretenar, D.; Niksic, T.; Meng, J.

    2012-10-20

    The structure of low-energy collective states in the neutron-rich nucleus {sup 44}S is analyzed using a microscopic collective Hamiltonian model based on energy density functionals (EDFs). The calculated triaxial energy map, low-energy spectrum and corresponding probability distributions indicate a coexistence of prolate and oblate shapes in this nucleus.

  19. Variational test on the relationship between gradient expansion terms in the kinetic energy density functional

    NASA Astrophysics Data System (ADS)

    Glossman, M. Daniel; Castro, Eduardo A.

    1989-05-01

    By using an approximate analytical trial density and the consideration of an energy density functional which includes a modified gradient correction, the relationship between the zeroth-order and the first gradient correction is tested and the results compared with those obtained through the use of Hartree-Fock-Roothaan-Clementi densities.

  20. High Energy Density Battery Lithium Thionyl Chloride Improved Reverse Voltage Design.

    DTIC Science & Technology

    1981-12-01

    BATTERY LITHIUM THIONYL CHLORIDE IMPROVED R-ETC(U) DEC 81 A E ZOLLA N660011-C-0310...HIGH ENERGY DENSITY BATTERY LITHIUM THIONYL CHLORIDE IMPROVED REVERSE VOLTAGE DESIGN Dr. A. E. Zolla Altus Corporation C:1 1610 Crane Court San Jose...reverse aide If necesary and identify by block number) Lithium Battery Lithium Thionyl Chloride High Energy Density Battery Voltage Reversal Battery

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

    DOE PAGES

    Valdivia, M. P.; Stutman, D.; Stoeckl, C.; ...

    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.

  2. 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.

  3. Supernova and baryon acoustic oscillation constraints on (new) polynomial dark energy parametrizations: current results and forecasts

    NASA Astrophysics Data System (ADS)

    Sendra, Irene; Lazkoz, Ruth

    2012-05-01

    In this work we introduce two new polynomial parametrizations of dark energy and explore their correlation properties. The parameters to fit are the equation-of-state values at z= 0 and z= 0.5, which have naturally low correlation and have already been shown to improve the popular Chevallier-Polarski-Linder (CPL) parametrization. We test our models with low-redshift astronomical probes: type Ia supernovae and baryon acoustic oscillations (BAO), in the form of both current and synthetic data. Specifically, we present simulations of measurements of the radial and transversal BAO scales similar to those expected in a BAO high-precision spectroscopic redshift survey such as EUCLID. According to the Bayesian deviance information criterion (DIC), which penalizes large errors and correlations, we show that our models perform better than the CPL reparametrization proposed by Wang (in terms of z= 0 and z= 0.5). This is due to the combination of lower correlation and smaller relative errors. The same holds for a frequentist perspective: the figure-of-merit is larger for our parametrizations.

  4. Health sensor for human body by using infrared, acoustic energy and magnetic signature

    NASA Astrophysics Data System (ADS)

    Wu, Jerry

    2013-05-01

    There is a general chain of events that applies to infections. Human body infection could causes by many different types of bacteria and virus in different areas or organ systems. In general, doctor can't find out the right solution/treatment for infections unless some certain types of bacteria or virus are detected. These detecting processes, usually, take few days to one week to accomplish. However, some infections of the body may not be able to detect at first round and the patient may lose the timing to receive the proper treatment. In this works, we base on Chi's theory which is an invisible circulation system existed inside the body and propose a novel health sensor which summarizes human's infrared, acoustic energy and magnetic signature and find out, in minutes, the most possible area or organ system that cause the infection just like what Chi-Kung master can accomplish. Therefore, the detection process by doctor will be shortened and it raises the possibility to give the proper treatment to the patient in the earliest timing.

  5. Throughput and energy efficiency of a cooperative hybrid ARQ protocol for underwater acoustic sensor networks.

    PubMed

    Ghosh, Arindam; Lee, Jae-Won; Cho, Ho-Shin

    2013-11-08

    Due to its efficiency, reliability and better channel and resource utilization, cooperative transmission technologies have been attractive options in underwater as well as terrestrial sensor networks. Their performance can be further improved if merged with forward error correction (FEC) techniques. In this paper, we propose and analyze a retransmission protocol named Cooperative-Hybrid Automatic Repeat reQuest (C-HARQ) for underwater acoustic sensor networks, which exploits both the reliability of cooperative ARQ (CARQ) and the efficiency of incremental redundancy-hybrid ARQ (IR-HARQ) using rate-compatible punctured convolution (RCPC) codes. Extensive Monte Carlo simulations are performed to investigate the performance of the protocol, in terms of both throughput and energy efficiency. The results clearly reveal the enhancement in performance achieved by the C-HARQ protocol, which outperforms both CARQ and conventional stop and wait ARQ (S&W ARQ). Further, using computer simulations, optimum values of various network parameters are estimated so as to extract the best performance out of the C-HARQ protocol.

  6. Characterisation of acoustic energy content in an experimental combustion chamber with and without external forcing

    NASA Astrophysics Data System (ADS)

    Webster, S.; Hardi, J.; Oschwald, M.

    2015-03-01

    The influence of injection conditions on rocket engine combustion stability is investigated for a sub-scale combustion chamber with shear coaxial injection elements and the propellant combination hydrogen-oxygen. The experimental results presented are from a series of tests conducted at subcritical and supercritical pressures for oxygen and for both ambient and cryogenic temperature hydrogen. The stability of the system is characterised by the root mean squared amplitude of dynamic combustion chamber pressure in the upper part of the acoustic spectrum relevant for high frequency combustion instabilities. Results are presented for both unforced and externally forced combustion chamber configurations. It was found that, for both the unforced and externally forced configurations, the injection velocity had the strongest influence on combustion chamber stability. Through the use of multivariate linear regression the influence of hydrogen injection temperature and hydrogen injection mass flow rate were best able to explain the variance in stability for dependence on injection velocity ratio. For unforced tests turbulent jet noise from injection was found to dominate the energy content of the signal. For the externally forced configuration a non-linear regression model was better able to predict the variance, suggesting the influence of non-linear behaviour. The response of the system to variation of injection conditions was found to be small; suggesting that the combustion chamber investigated in the experiment is highly stable.

  7. Meta-aromatic polyurea with high dipole moment and dipole density for energy storage capacitors

    NASA Astrophysics Data System (ADS)

    Wu, Shan; Lin, Minren; Burlingame, Quinn; Zhang, Q. M.

    2014-02-01

    A dielectric polymer, i.e., meta-aromatic polyurea(meta-PU) was developed and investigated for high energy density, low loss energy storage capacitors. Modifications to the molecular structure can tune the dipolar density and dipole moment in the polyurea systems to improve the dielectric properties. Meta-PU was synthesized via a green synthetic route with a higher volume dipolar density than the aromatic polyurea previously reported. The meta-PU has an enhanced dielectric constant, higher energy density, and a high electrical breakdown. A high storage electrical energy density of 13 J/cm3 and energy storage efficiency of 91% can be achieved at 670 MV/electric field.

  8. 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.

  9. A comparison of three methods of determination of energy density of elite figure skaters.

    PubMed

    Ziegler, Paula J; Nelson, Judith A; Tay, Chloe; Bruemmer, Barbara; Drewnowski, Adam

    2005-10-01

    Dietary energy density (kcal/g) is defined as available dietary energy per unit weight or volume of food. The consumption of energy-dense foods has been associated with increased obesity risk and with excessive weight gain. The objectives of this study were to compare how dietary energy density, calculated using three different methods relates to food choices and nutrient composition of the diets of elite figure skaters. Participants were 159 elite figure skaters attending training camps. Mean age was 18.4 y for boys (n = 79) and 15.9 y for girls (n = 80). Heights and weights were measured to calculate body-mass indices (BMI). Dietary intakes were based on 3-d food records analyzed using the Nutritionist IV program. Mean energy intakes were 2326 kcal/d for boys and 1545 kcal/d for girls. Dietary energy density,,based on foods and caloric beverages only, was 1.0 kcal/g. Dietary ED was positively associated with percent energy from fat and negatively with percent energy from sugar. The main sources of dietary energy in this group were baked goods, cereals, regular soda, low-fat milk, fruit juices, bagels and pizza. Percent energy from fast foods was associated with higher dietary energy density, whereas percent energy from dairy products, soft drinks, vegetables, and fruit was associated with lower dietary energy density. These results are consistent with past observations; higher energy density diets were higher in fat. In contrast, there was a negative relationship between sugar content and energy density of the diet.

  10. Laser and acoustic lens for lithotripsy

    DOEpatents

    Visuri, Steven R.; Makarewicz, Anthony J.; London, Richard A.; Benett, William J.; Krulevitch, Peter; Da Silva, Luiz B.

    2002-01-01

    An acoustic focusing device whose acoustic waves are generated by laser radiation through an optical fiber. The acoustic energy is capable of efficient destruction of renal and biliary calculi and deliverable to the site of the calculi via an endoscopic procedure. The device includes a transducer tip attached to the distal end of an optical fiber through which laser energy is directed. The transducer tip encapsulates an exogenous absorbing dye. Under proper irradiation conditions (high absorbed energy density, short pulse duration) a stress wave is produced via thermoelastic expansion of the absorber for the destruction of the calculi. The transducer tip can be configured into an acoustic lens such that the transmitted acoustic wave is shaped or focused. Also, compressive stress waves can be reflected off a high density/low density interface to invert the compressive wave into a tensile stress wave, and tensile stresses may be more effective in some instances in disrupting material as most materials are weaker in tension than compression. Estimations indicate that stress amplitudes provided by this device can be magnified more than 100 times, greatly improving the efficiency of optical energy for targeted material destruction.

  11. Synthesis of Novel High Energy Density Materials Using Nitrocarbenes

    DTIC Science & Technology

    1992-02-21

    synthesis is our finding that the combination of titanium tetrachloride/methylene bromide/zinc smoothly converts the caged diketone to the bismethylene...AD-A248 465 AO PAGE ft 07ŕ Februa re 21 , 992uq" Final~o Repotm 8//9 -12319 4. TITLE AND SUBTITLE S. FUNOING NUMBERS Synthesis of Novel High Energy...theory to predict the structures and energies of potential energetic molecules and to guide the synthesis of the more promising candidate molecules, 2

  12. The Search for New High-Energy-Density Materials

    DTIC Science & Technology

    2014-01-01

    a Mn atom with halogen atoms and stability of its half-filled 3d- shell ”, J. Chem. Phys. 134, 234311 (2011) Pathak, B., Samanta, D., Ahuja, R...Society, Cocoa Beach, FL, February 21-25, 2010 US-Egypt Advanced Studies Institute (ASI) on “Nanomaterials and Nanocatalysis for Energy

  13. Free energies, vacancy concentrations, and density distribution anisotropies in hard-sphere crystals: A combined density functional and simulation study

    NASA Astrophysics Data System (ADS)

    Oettel, M.; Görig, S.; Härtel, A.; Löwen, H.; Radu, M.; Schilling, T.

    2010-11-01

    We perform a comparative study of the free energies and the density distributions in hard-sphere crystals using Monte Carlo simulations and density functional theory (employing Fundamental Measure functionals). Using a recently introduced technique [T. Schilling and F. Schmid, J. Chem. Phys. 131, 231102 (2009)10.1063/1.3274951] we obtain crystal free energies to a high precision. The free energies from fundamental measure theory are in good agreement with the simulation results and demonstrate the applicability of these functionals to the treatment of other problems involving crystallization. The agreement between fundamental measure theory and simulations on the level of the free energies is also reflected in the density distributions around single lattice sites. Overall, the peak widths and anisotropy signs for different lattice directions agree, however, it is found that fundamental measure theory gives slightly narrower peaks with more anisotropy than seen in the simulations. Among the three types of fundamental measure functionals studied, only the White Bear II functional [H. Hansen-Goos and R. Roth, J. Phys.: Condens. Matter 18, 8413 (2006)10.1088/0953-8984/18/37/002] exhibits sensible results for the equilibrium vacancy concentration and a physical behavior of the chemical potential in crystals constrained by a fixed vacancy concentration.

  14. Measuring Turbulence from Moored Acoustic Doppler Velocimeters. A Manual to Quantifying Inflow at Tidal Energy Sites

    SciTech Connect

    Kilcher, Levi; Thomson, Jim; Talbert, Joe; DeKlerk, Alex

    2016-03-01

    This work details a methodology for measuring hub height inflow turbulence using moored acoustic Doppler velocimiters (ADVs). This approach is motivated by the shortcomings of alternatives. For example, remote velocity measurements (i.e., from acoustic Doppler profilers) lack sufficient precision for device simulation, and rigid tower-mounted measurements are very expensive and technically challenging in the tidal environment. Moorings offer a low-cost, site-adaptable and robust deployment platform, and ADVs provide the necessary precision to accurately quantify turbulence.

  15. Method and system for generating a beam of acoustic energy from a borehole, and applications thereof

    DOEpatents

    Johnson, Paul A [Santa Fe, NM; Ten Cate, James A [Los Alamos, NM; Guyer, Robert [Reno, NV; Le Bas, Pierre-Yves [Los Alamos, NM; Vu, Cung [Houston, TX; Nihei, Kurt [Oakland, CA; Schmitt, Denis P [Katy, TX; Skelt, Christopher [Houston, TX

    2012-02-14

    A compact array of transducers is employed as a downhole instrument for acoustic investigation of the surrounding rock formation. The array is operable to generate simultaneously a first acoustic beam signal at a first frequency and a second acoustic beam signal at a second frequency different than the first frequency. These two signals can be oriented through an azimuthal rotation of the array and an inclination rotation using control of the relative phases of the signals from the transmitter elements or electromechanical linkage. Due to the non-linearity of the formation, the first and the second acoustic beam signal mix into the rock formation where they combine into a collimated third signal that propagates in the formation along the same direction than the first and second signals and has a frequency equal to the difference of the first and the second acoustic signals. The third signal is received either within the same borehole, after reflection, or another borehole, after transmission, and analyzed to determine information about rock formation. Recording of the third signal generated along several azimuthal and inclination directions also provides 3D images of the formation, information about 3D distribution of rock formation and fluid properties and an indication of the dynamic acoustic non-linearity of the formation.

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

    PubMed

    Gao, Jie; Abruña, Héctor D

    2014-03-06

    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.

  17. 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.

  18. Extended MHD Effects in High Energy Density Experiments

    NASA Astrophysics Data System (ADS)

    Seyler, Charles

    2016-10-01

    The MHD model is the workhorse for computational modeling of HEDP experiments. Plasma models are inheritably limited in scope, but MHD is expected to be a very good model for studying plasmas at the high densities attained in HEDP experiments. There are, however, important ways in which MHD fails to adequately describe the results, most notably due to the omission of the Hall term in the Ohm's law (a form of extended MHD or XMHD). This talk will discuss these failings by directly comparing simulations of MHD and XMHD for particularly relevant cases. The methodology is to simulate HEDP experiments using a Hall-MHD (HMHD) code based on a highly accurate and robust Discontinuous Galerkin method, and by comparison of HMHD to MHD draw conclusions about the impact of the Hall term. We focus on simulating two experimental pulsed power machines under various scenarios. We examine the MagLIF experiment on the Z-machine at Sandia National Laboratories and liner experiments on the COBRA machine at Cornell. For the MagLIF experiment we find that power flow in the feed leads to low density plasma ablation into the region surrounding the liner. The inflow of this plasma compresses axial magnetic flux onto the liner. In MHD this axial flux tends to resistively decay, whereas in HMHD a force-free current layer sustains the axial flux on the liner leading to a larger ratio of axial to azimuthal flux. During the liner compression the magneto-Rayleigh-Taylor instability leads to helical perturbations due to minimization of field line bending. Simulations of a cylindrical liner using the COBRA machine parameters can under certain conditions exhibit amplification of an axial field due to a force-free low-density current layer separated by some distance from the liner. This results in a configuration in which there is predominately axial field on the liner inside the current layer and azimuthal field outside the layer. We are currently attempting to experimentally verify the simulation

  19. An Energy Signature Scheme for Steam Trap Assessment and Flow Rate Estimation Using Pipe-Induced Acoustic Measurements

    SciTech Connect

    Olama, Mohammed M; Allgood, Glenn O; Kuruganti, Phani Teja; Lake, Joe E

    2012-01-01

    The US Congress has passed legislation dictating that all government agencies establish a plan and process for improving energy efficiencies at their sites. In response to this legislation, Oak Ridge National Laboratory (ORNL) has recently conducted a pilot study to explore the deployment of a wireless sensor system for a real-time measurement-based energy efficiency optimization framework within the steam distribution system within the ORNL campus. We make assessments on the real-time status of the distribution system by observing the state measurements of acoustic sensors mounted on the steam pipes/traps/valves. In this paper, we describe a spectral-based energy signature scheme that interprets acoustic vibration sensor data to estimate steam flow rates and assess steam traps health status. Experimental results show that the energy signature scheme has the potential to identify different steam trap health status and it has sufficient sensitivity to estimate steam flow rate. Moreover, results indicate a nearly quadratic relationship over the test region between the overall energy signature factor and flow rate in the pipe. The analysis based on estimated steam flow and steam trap status helps generate alerts that enable operators and maintenance personnel to take remedial action. The goal is to achieve significant energy-saving in steam lines by monitoring and acting on leaking steam pipes/traps/valves.

  20. High Energy Density Nastic Structures Using Biological Transport Mechanisms

    DTIC Science & Technology

    2007-02-28

    permeable membranes . This concept is based on the pressurization of cells similar to the process that plants use to maintain homeostasis and regulate...two chambers separated by a semi-permeable membrane substrate that contains protein transporters suspended in a lipid bilayer. The protein...transporters convert biochemical energy in the form of ATP into a protein gradient across the semi- permeable membrane . The proton gradient, in turn, induces

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

    NASA Astrophysics Data System (ADS)

    Kuklja, Maija M.; Tsyshevsky, Roman V.; Rashkeev, Sergey

    2017-01-01

    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 point 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.

  2. Tuning the electron energy by controlling the density perturbation position in laser plasma accelerators

    SciTech Connect

    Brijesh, P.; Thaury, C.; Phuoc, K. T.; Corde, S.; Lambert, G.; Malka, V.; Mangles, S. P. D.; Bloom, M.; Kneip, S.

    2012-06-15

    A density perturbation in an underdense plasma was used to improve the quality of electron bunches produced in the laser-plasma wakefield acceleration scheme. Quasi-monoenergetic electrons were generated by controlled injection in the longitudinal density gradients of the density perturbation. By tuning the position of the density perturbation along the laser propagation axis, a fine control of the electron energy from a mean value of 60 MeV to 120 MeV has been demonstrated with a relative energy-spread of 15 {+-} 3.6%, divergence of 4 {+-} 0.8 mrad, and charge of 6 {+-} 1.8 pC.

  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 PAGES

    Li, Bin; Nie, Zimin; Vijayakumar, M.; ...

    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. Volume and surface contributions to the nuclear symmetry energy within the coherent density fluctuation model

    NASA Astrophysics Data System (ADS)

    Antonov, A. N.; Gaidarov, M. K.; Sarriguren, P.; Moya de Guerra, E.

    2016-07-01

    The volume and surface components of the nuclear symmetry energy (NSE) and their ratio are calculated within the coherent density fluctuation model (CDFM). The estimations use the results of the model for the NSE in finite nuclei based on the Brueckner energy-density functional for nuclear matter. In addition, we present results for the NSE and its volume and surface contributions obtained by using the Skyrme energy-density functional. The CDFM weight function is obtained using the proton and neutron densities from the self-consistent HF+BCS method with Skyrme interactions. We present and discuss the values of the volume and surface contributions to the NSE and their ratio obtained for the Ni, Sn, and Pb isotopic chains, studying their isotopic sensitivity. The results are compared with estimations of other approaches which have used available experimental data on binding energies, neutron-skin thicknesses, excitation energies to isobaric analog states (IAS), and also with results of other theoretical methods.

  6. Asymptotic formula far from nucleus for exchange energy density in Hartree-Fock theory of closed-shell atoms

    NASA Astrophysics Data System (ADS)

    March, N. H.

    In Hartree-Fock theory, the exchange energy density can be expressed solely in terms of the first-order density matrix. Far from the nucleus of a closed-shell atom, idem potency of the density matrix yields the exchange energy density as the magnitude of the Coulomb energy e2/r times the electron density ρ. Thus two lengths enter the asymptotic form in contrast to ρ-1/3 alone of local-density theory.

  7. Role of the density, density effect and mean excitation energy in solid-state detectors for small photon fields

    NASA Astrophysics Data System (ADS)

    Andreo, Pedro; Benmakhlouf, Hamza

    2017-02-01

    A number of recent publications on small photon beam dosimetry aim at contributing to the understanding of the response of solid-state detectors in small fields. Some of them assign the difference in response to the mass density, or to the electron density, of the sensitive detector material relative to that of water. This work analyses the role of the mass and electron density (ρ,{{n}\\text{e}} ), density effect (δ) and mean excitation energy (I-value) of some detector materials in a 6 MV photon beam of 0.5 cm radius, its rationale being that the response of a detector depends critically on the stopping-power ratio detector-to-water. The influence on the detector response of volume scaling by electron density, and of electron single and multiple scattering, is also investigated. Detector materials are water, diamond and silicon, and additional materials are included for consistency in the analysis. A detailed analysis on the (ρ,I,δ ) dependence of stopping-power ratios shows that the density effect δ depends both on the electron density and on the I-value of the medium, but not on the mass density ρ alone as is usually assumed. This leads to a double dependence of stopping-power ratios on the I-value and questions the adequacy of a ‘density perturbation factor’ or of common interpretations of detector response in terms of ρ alone. Differences in response can be described in terms of the variation of stopping power ratios detector-to-water, mainly due to different I-values and to a lesser extent to different values of electron density. It is found that at low energies the trend of Monte Carlo-calculated electron fluence spectra inside the detector materials depends solely on their I-values. No dependence on mass density or density effect alone is observed at any energy. The trend of restricted-cema ratios to water (as a substitute of absorbed dose ratios) follows that of stopping-power ratios at 1 MeV, the most probable energy of differential

  8. Microscopically-Based Energy Density Functionals for Nuclei Using the Density Matrix Expansion. I: Implementation and Pre-Optimization

    SciTech Connect

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

    2010-01-01

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

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

    SciTech Connect

    Stoitsov, M.; Kortelainen, M.; Schunck, N.; Bogner, S. K.; Gebremariam, B.; Duguet, T.

    2010-11-15

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

  10. Effect of ion temperature and plasma density on an ion-acoustic soliton in a collisionless relativistic plasma: An application to radiation belts

    SciTech Connect

    Singh, S.; Dahiya, R.P. )

    1990-05-01

    The effect of ion temperature and plasma density on the behavior of an ion-acoustic soliton in a collisionless relativistic plasma is studied. Based on an appropriate set of coordinate transformations, a reductive perturbation analysis is carried out to obtain the Korteweg--de Vries (KdV) equation for the one-dimensional soliton motion. By solving this equation for a single soliton, simple expressions for the soliton phase velocity, soliton amplitude, soliton width, peak soliton ion density, and peak soliton potential are derived. These results are applied to the plasma parameters of the radiation belts. The soliton phase velocity {lambda}{sub 0} increases with an increase in the relativistic effect. The effect of the ion temperature on {lambda}{sub 0} is, however, negligible. It is shown that for the constant ion temperature and plasma density, the soliton amplitude, soliton phase velocity, peak soliton ion density, and peak soliton potential increase, and the soliton width decreases as the relativistic effect increases. With the increasing ion temperature, however, the soliton behaves in an entirely different way. It is further shown that for a constant value of the ion temperature, the amplitude and peak ion density increase and the width decreases, whereas the peak potential remains unchanged as the plasma density increases.

  11. Ab initio research of energy loss for energetic protons in solid-density Be

    NASA Astrophysics Data System (ADS)

    He, Bin; Meng, Xu-Jun; Wang, Zhi-Gang; Wang, Jian-Guo

    2017-03-01

    Ab initio research of energy loss for energetic protons in solid-density Be is made based on the average atom model. Our results are found in good agreement with the recent experiment for both warm and cool matter. Our results are compared with the local density approximation model and the reason for their difference is also explored. The energy loss at smaller projectile energies is predicted by our model and local density approximation, which helps probe the higher reliability of the proving model and judge the existence of the non-Fermi-Dirac velocity distribution for free electrons exists in dense plasmas in future.

  12. Dehydration of seabird prey during transport to the colony: Effects on wet weight energy densities

    USGS Publications Warehouse

    Montevecchi, W.A.; Piatt, John F.

    1987-01-01

    We present evidence to indicate that dehydration of prey transported by seabirds from capture sites at sea to chicks at colonies inflates estimates of wet weight energy densities. These findings and a comparison of wet and dry weight energy densities reported in the literature emphasize the importance of (i) accurate measurement of the fresh weight and water content of prey, (ii) use of dry weight energy densities in comparisons among species, seasons, and regions, and (iii) cautious interpretation and extrapolation of existing data sets.

  13. 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

  14. High Energy Density Physics technical quarterly, October--December 1994. Volume 3

    SciTech Connect

    1995-09-01

    The High Energy Density Physics Technical Quarterly (formerly the AGEX 2 Technical Quarterly) publishes short technical contributions on above ground experiments that use pulsed power and laser drivers. The Quarterly is intended to provide rapid exposure of timely technical ideas and results as well as a means for documenting High Energy Density Physics progress and scientific quality for the High Energy Density Physics community. Two articles are included in this volume. They are ``Simulation and Analysis of PEGII-25`` and ``Resistor Developments for Atlas Marx Modules``.

  15. The symmetry energy at suprasaturation density and the ASY-EOS experiment at GSI

    NASA Astrophysics Data System (ADS)

    De Filippo, E.; Russotto, P.; Acosta, L.; Adamczyk, M.; Al-Ajlan, A.; Al-Garawi, M.; Al-Homaidhi, S.; Amorini, F.; Auditore, L.; Aumann, T.; Ayyad, Y.; Basrak, Z.; Benlliure, J.; Boisjoli, M.; Boretzky, K.; Brzychczyk, J.; Budzanowski, A.; Caesar, C.; Cardella, G.; Cammarata, P.; Chajecki, Z.; Chartier, M.; Chbihi, A.; Colonna, M.; Cozma, M. D.; Czech, B.; Di Toro, M.; Famiano, M.; Gannon, S.; Gašparić, I.; Grassi, L.; Guazzoni, C.; Guazzoni, P.; Heil, M.; Heilborn, L.; Introzzi, R.; Isobe, T.; Kezzar, K.; Kiš, M.; Krasznahorkay, A.; Kupny, S.; Kurz, N.; La Guidara, E.; Lanzalone, G.; Lasko, P.; Le Fèvre, A.; Leifels, Y.; Lemmon, R. C.; Li, Q. F.; Lombardo, I.; Łukasik, J.; Lynch, W. G.; Marini, P.; Matthews, Z.; May, L.; Minniti, T.; Mostazo, M.; Pagano, A.; Pagano, E. V.; Papa, M.; Pawłowski, P.; Pirrone, S.; Politi, G.; Porto, F.; Reviol, W.; Riccio, F.; Rizzo, F.; Rosato, E.; Rossi, D.; Santoro, S.; Sarantites, D. G.; Simon, H.; Skwirczynska, I.; Sosin, Z.; Stuhl, L.; Trautmann, W.; Trifirò, A.; Trimarchi, M.; Tsang, M. B.; Verde, G.; Veselsky, M.; Vigilante, M.; Wang, Yongjia; Wieloch, A.; Wigg, P.; Winkelbauer, J.; Wolter, H. H.; Wu, P.; Yennello, S.; Zambon, P.; Zetta, L.; Zoric, M.

    2017-03-01

    The ASY-EOS experiment at GSI laboratory measured the direct and elliptic flow of neutrons and light charged particles in the reaction 197Au+197 Au at 400 A MeV incident energy. The ratio of elliptic flow of neutrons with respect to that of the light charged particles was used as main experimental observable to probe the density dependence of the symmetry energy term of the nuclear equation of state. Results, obtained by comparison of the experimental data with the UrQMD model predictions, strongly support a moderately soft to linear density dependence of the symmetry energy at suprasaturation densities below 2ρ0.

  16. Acoustic neuroma

    MedlinePlus

    Vestibular schwannoma; Tumor - acoustic; Cerebellopontine angle tumor; Angle tumor; Hearing loss - acoustic; Tinnitus - acoustic ... Acoustic neuromas have been linked with the genetic disorder neurofibromatosis type 2 (NF2). Acoustic neuromas are uncommon.

  17. Acoustic Test Results of Melamine Foam with Application to Payload Fairing Acoustic Attenuation Systems

    NASA Technical Reports Server (NTRS)

    Hughes, William O.; McNelis, Anne M.

    2014-01-01

    A spacecraft at launch is subjected to a harsh acoustic and vibration environment resulting from the passage of acoustic energy, created during the liftoff of a launch vehicle, through the vehicle's payload fairing. In order to ensure the mission success of the spacecraft it is often necessary to reduce the resulting internal acoustic sound pressure levels through the usage of acoustic attenuation systems. Melamine foam, lining the interior walls of the payload fairing, is often utilized as the main component of such a system. In order to better understand the acoustic properties of melamine foam, with the goal of developing improved acoustic attenuation systems, NASA has recently performed panel level testing on numerous configurations of melamine foam acoustic treatments at the Riverbank Acoustical Laboratory. Parameters assessed included the foam's thickness and density, as well as the effects of a top outer cover sheet material and mass barriers embedded within the foam. This testing followed the ASTM C423 standard for absorption and the ASTM E90 standard for transmission loss. The acoustic test data obtained and subsequent conclusions are the subjects of this paper.

  18. Simultaneous backward data transmission and power harvesting in an ultrasonic transcutaneous energy transfer link employing acoustically dependent electric impedance modulation.

    PubMed

    Ozeri, Shaul; Shmilovitz, Doron

    2014-09-01

    The advancement and miniaturization of body implanted medical devices pose several challenges to Ultrasonic Transcutaneous Energy Transfer (UTET), such as the need to reduce the size of the piezoelectric resonator, and the need to maximize the UTET link power-transfer efficiency. Accordingly, the same piezoelectric resonator that is used for energy harvesting at the body implant, may also be used for ultrasonic backward data transfer, for instance, through impedance modulation. This paper presents physical considerations and design guidelines of the body implanted transducer of a UTET link with impedance modulation for a backward data transfer. The acoustic matching design procedure was based on the 2×2 transfer matrix chain analysis, in addition to the Krimholtz Leedom and Matthaei KLM transmission line model. The UTET power transfer was carried out at a frequency of 765 kHz, continuous wave (CW) mode. The backward data transfer was attained by inserting a 9% load resistance variation around its matched value (550 Ohm), resulting in a 12% increase in the acoustic reflection coefficient. A backward data transmission rate of 1200 bits/s was experimentally demonstrated using amplitude shift keying, simultaneously with an acoustic power transfer of 20 mW to the implant.

  19. Acoustic Suppression Systems and Related Methods

    NASA Technical Reports Server (NTRS)

    Kolaini, Ali R. (Inventor); Kern, Dennis L. (Inventor)

    2013-01-01

    An acoustic suppression system for absorbing and/or scattering acoustic energy comprising a plurality of acoustic targets in a containment is described, the acoustic targets configured to have resonance frequencies allowing the targets to be excited by incoming acoustic waves, the resonance frequencies being adjustable to suppress acoustic energy in a set frequency range. Methods for fabricating and implementing the acoustic suppression system are also provided.

  20. The Evolution of Ring Current Energy Density and Energy Content during Geomagnetic Storms Based on Van Allen Probes Measurements

    NASA Astrophysics Data System (ADS)

    Zhao, H.; Li, X.; Baker, D. N.; Claudepierre, S. G.; Fennell, J. F.; Blake, J. B.; Larsen, B.; Skoug, R. M.; Funsten, H. O.; Freidel, R. H. W.; Reeves, G. D.; Spence, H. E.; Mitchell, D. G.; Lanzerotti, L. J.; Rodriguez, J. V.

    2015-12-01

    Enabled by the comprehensive measurements from the MagEIS, HOPE, and RBSPICE instruments onboard Van Allen Probes in the heart of the radiation belt, the relative contributions of particles with different energies and species to the ring current energy density and their dependence on the geomagnetic storms and storm phases are quantified. During the main phases of moderate storms (with minimum Dst between -50 nT and -100 nT), ions of energies < 50 keV and electrons of energies of <35 keV contribute more significantly to the ring current energy than those of higher energies. During the recovery phase and quiet times higher energy protons dominate the ring current energy content. For the March 29, 2013 moderate storm, the contribution from O+ is ~25% of the ring current energy content during the main phase, and the majority of that comes from < 50 keV O+. This indicates that even during moderate geomagnetic storms the ionosphere is still an important contributor to the ring current ions and low energy O+ plays an important role in ring current dynamics. The contribution of electrons to the ring current energy content is up to ~7% during this moderate storm and the magnetic local time dependence of electron energy density is also investigated. However, the ring current energy partitions for different species and energy ranges are very different during the great storm of 17 March 2015 (with minimum Dst<-210 nT).

  1. 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.

  2. Density functional calculations for a high energy density compound of formula C6H 6-n (NO 2) n.

    PubMed

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

    2012-08-01

    A series of polynitroprismanes, C(6)H(6-n )(NO(2))(n) (n = 1-6) intended for use as high energy density compounds (HEDCs) were designed computationally. Their electronic structures, heats of formation, interactions between nitro groups, specific enthalpies of combustion, bond dissociation energies, and explosive performances (detonation velocities and detonation pressures) were calculated using density functional theory (DFT) with the 6-311 G** basis set. The results showed that all of the polynitroprismanes had high positive heats of formation that increased with the number of substitutions for the prismane derivatives, while the specific enthalpy of combustion decreased as the number of nitro groups increased. In addition, the range of enthalpy of combustion reducing is getting smaller. Interactions between ortho (vicinal) groups deviate from the group additivity rule and decrease as the number of nitro groups increases. In terms of thermodynamic stability, all of the polynitroprismanes had higher bond dissociation energies (BDEs) than RDX and HMX. Detonation velocities and detonation pressures were estimated using modified Kamlet-Jacobs equations based on the heat of detonation (Q) and the theoretical density of the molecule (ρ). It was found that ρ, D, and P are strongly linearly related to the number of nitro groups. Taking both their energetic properties and thermal stabilities into account, pentanitroprismane and hexanitroprismane are potential candidate HEDCs.

  3. 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.

  4. Modern foraging: Presence of food and energy density influence motivational processing of food advertisements.

    PubMed

    Bailey, Rachel L

    2016-12-01

    More energy dense foods are preferable from an optimal foraging perspective, which suggests these foods are more motivationally relevant due to their greater capability of fulfilling biological imperatives. This increase in motivational relevance may be exacerbated in circumstances where foraging will be necessary. This study examined how food energy density and presence of food in the immediate environment interacted to influence motivational processing of food advertisements. N = 58 adults viewed advertisements for foods varying in energy density in contexts where the advertised food was actually present in the viewing room or not. Advertisements for more energy dense foods elicited greater skin conductivity level compared to ads for less energy dense foods when food was not present. All ads elicited decreases in corrugator supercilii activation indicating positive emotional response resultant from appetitive motivational activation, though the greatest activation was exhibited toward higher energy density foods when food was present. This supports an optimal foraging perspective and has implications for healthy eating interventions.

  5. 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.

  6. 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.

  7. Charged Particle Transport in High-Energy-Density Matter

    NASA Astrophysics Data System (ADS)

    Stanton, Liam; Murillo, Michael

    2016-10-01

    Transport coefficients for dense plasmas have been numerically computed using an effective Boltzmann approach. We have developed a simplified effective potential approach that yields accurate fits for all of the relevant cross sections and collision integrals. Our results have been validated with molecular dynamics simulations for self-diffusion, interdiffusion, viscosity, thermal conductivity and stopping power. Molecular dynamics has also been used to examine the underlying assumptions of the Boltzmann approach through a categorization of behaviors of the velocity autocorrelation function in the Yukawa phase diagram. Using a velocity-dependent screening model, we examine the role of dynamical screening in transport as well. Implications of these results for Coulomb logarithm approaches are discussed. This work is performed under the auspices of the U. S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  8. From dilute matter to the equilibrium point in the energy-density-functional theory

    NASA Astrophysics Data System (ADS)

    Yang, C. J.; Grasso, M.; Lacroix, D.

    2016-09-01

    Due to the large value of the scattering length in nuclear systems, standard density-functional theories based on effective interactions usually fail to reproduce the nuclear Fermi-liquid behavior both at very low densities and close to equilibrium. Guided on one side by the success of the Skyrme density functional and, on the other side, by resummation techniques used in effective field theories for systems with large scattering lengths, a new energy-density functional is proposed. This functional, adjusted on microscopic calculations, reproduces the nuclear equations of state of neutron and symmetric matter at various densities. Furthermore, it provides reasonable saturation properties as well as an appropriate density dependence for the symmetry energy.

  9. 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%.

  10. 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.

  11. Frequency dependent power and energy flux density equations of the electromagnetic wave

    NASA Astrophysics Data System (ADS)

    Muhibbullah, M.; Haleem, Ashraf M. Abdel; Ikuma, Yasuro

    The calculation of the power and energy of the electromagnetic wave is important for numerous applications. There are some equations to compute the power and energy density of the electromagnetic wave radiation. For instance, the Poynting vector is frequently used to calculate the power density. However those including the Poynting vector are not perfect to represent the actual values because the equations are frequency independent. In the present study we have derived the frequency-dependent equations to calculate the power and energy flux density of the electromagnetic wave by help of the classical electromagnetic theories. It is seems that the Poynting vector with a certain electric and magnetic fields is correct only for a specific frequency. However our equations are perfect to calculate the values of the power and energy flux density for all frequencies of the electromagnetic radiation. The equations may help to develop the applications of the electromagnetic wave radiation.

  12. Development of novel cathodes for high energy density lithium batteries

    NASA Astrophysics Data System (ADS)

    Bhargav, Amruth

    Lithium based batteries have become ubiquitous with our everyday life. They have propelled a generation of smart personal electronics and electric transport. Their use is now percolating to various fields as a source of energy to facilitate the operation of devices from nanoscale to mega scale. This need for a portable energy source has led to tremendous scientific interest in this field to develop electrochemical devices like batteries with higher capacities, longer cycle life and increased safety at a low cost. To this end, the research presented in this thesis focuses on two emerging and promising technologies called lithium-oxygen (Li-O2) and lithium-sulfur (Li-S) batteries. These batteries can offer an order of magnitude higher capacities through cheap, environmentally safe and abundant elements namely oxygen and sulfur. The first work introduces the concept of closed system lithium-oxygen batteries wherein the cell contains the discharge product of Li-O2 batteries namely, lithium peroxide (Li2O2) as the starting active material. The reversibility of this system is analyzed along with its rate performance. The possible use of such a cathode in a full cell is explored. Also, this concept is used to verify if all the lithium can be extracted from the cathode in the first charge. In the following work, lithium peroxide is chemically synthesized and deposited in a carbon nanofiber matrix. This forms a free standing cathode that shows high reversibility. It can be cycled up to 20 times and while using capacity control protocol, a cycle life of 50 is obtained. The cause of cell degradation and failure is also analyzed. In the work on full cell lithium-sulfur system, a novel electrolyte is developed that can support reversible lithium insertion and extraction from a graphite anode. A method to deposit solid lithium polysulfide is developed for the cathode. Coupling a lithiated graphite anode with the cathode using the new electrolyte yields a full cell whose

  13. 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.

  14. Combustion characteristics of high-energy/high-density hydrocarbon compounds

    SciTech Connect

    Segal, C.; Friedauer, M.J.; Udaykumar, H.S.; Shyy, W.

    1996-12-31

    The combustion characteristics of PCU Alkene Dimers (C{sub 22}H{sub 24}) are evaluated as solid fuels in high speed flows, at conditions typical for ramjet operation (i.e., Mach 0.25, stagnation temperature and pressure of 300 K and 150 kPa, respectively). Samples of the dimer are binded into a solid layer with a styrene-polybutadiene copolymer (8% w/w) on the test chamber wall and convectively ignited by a gaseous flame in air. The goals of this research are of both practical and fundamental relevance: (1) determine the ability of the high energy fuel to increase practical devices` performance, (2) quantify and improve the combustion characteristics of the alkene dimers (i.e., ignition, flame stability, particulate formation), (3) investigate the dynamics of the solid-gas interface combustion. To date, ignition times and rates of heat release were measured and the theoretical modelling was initiated. Preliminary results indicate that, in the present configuration, the dimer ignition times fall within the range reported in literature for other solid fuels. Large differences exist among different sets of data due primarily to nonsimilar geometrical configuration of the test. The dimer exhibits substantial rates of heat release in comparison with other solid fuels.

  15. 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.

  16. The National Ignition Facility (NIF) and High Energy Density Science Research at LLNL (Briefing Charts)

    DTIC Science & Technology

    2013-06-21

    The National Ignition Facility ( NIF ) and High Energy Density Science Research at LLNL Presentation to: IEEE Pulsed Power and Plasma Science...Conference C. J. Keane Director, NIF User Office June 21, 2013 1491978-1-4673-5168-3/13/$31.00 ©2013 IEEE Report Documentation Page Form ApprovedOMB No...4. TITLE AND SUBTITLE The National Ignition Facility ( NIF ) and High Energy Density Science Research at LLNL 5a. CONTRACT NUMBER 5b. GRANT

  17. 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.

  18. 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.

  19. 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

  20. 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.

  1. Influence of light energy and power density on the microhardness of two nanohybrid composites.

    PubMed

    Gritsch, Kerstin; Souvannasot, Sourasith; Schembri, Catherine; Farge, Pierre; Grosgogeat, Brigitte

    2008-02-01

    The purpose of this study was to investigate the role of light parameters on nanohybrid composite curing. Two nanohybrid resins were cured by two light-emitting diode (LED) devices and by one quartz-tungsten-halogen (QTH) device using different combinations of energy density and power density (8 J cm(-2) and 400 mW cm(-2); 8 J cm(-2) and 1,000 mW cm(-2); 16 J cm(-2) and 400 mW cm(-2); and 16 J cm(-2)-1,000 mW cm(-2)). The effects of these combinations on polymerization were assessed by measuring the Vickers microhardness. Data differed for the two composites and varied according to the light parameters and the nature of the curing device. For both resins, an energy density of 16 J cm(-2) yielded the best microhardness values at both the top and the bottom of the sample, independently of the power density. When using a lower energy density of 8 J cm(-2), a modulated power density was required to achieve proper curing at the bottom of the sample: 8 J cm(-2) and 400 mW cm(-2) induced greater values at the bottom surface. At an energy density of 16 J cm(-2), the power density was not relevant (no significant differences were found between 400 and 1,000 mW cm(-2)), except when the emission spectra of the light-curing units (LCUs) did not match exactly with the absorption spectra of the photoinitators included in the resins (greatest values with 16 J cm(-2) and 1,000 mW cm(-2)). These results suggest that above a certain energy density threshold, the power density may not significantly influence the polymerization kinetics.

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

    SciTech Connect

    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 a 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.

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

    DOE PAGES

    Valdivia, M. P.; Stutman, D.; Stoeckl, C.; ...

    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

  4. 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

    2015-12-09

    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.

  5. Excavation Equipment Recognition Based on Novel Acoustic Statistical Features.

    PubMed

    Cao, Jiuwen; Wang, Wei; Wang, Jianzhong; Wang, Ruirong

    2016-09-30

    Excavation equipment recognition attracts increasing attentions in recent years due to its significance in underground pipeline network protection and civil construction management. In this paper, a novel classification algorithm based on acoustics processing is proposed for four representative excavation equipments. New acoustic statistical features, namely, the short frame energy ratio, concentration of spectrum amplitude ratio, truncated energy range, and interval of pulse are first developed to characterize acoustic signals. Then, probability density distributions of these acoustic features are analyzed and a novel classifier is presented. Experiments on real recorded acoustics of the four excavation devices are conducted to demonstrate the effectiveness of the proposed algorithm. Comparisons with two popular machine learning methods, support vector machine and extreme learning machine, combined with the popular linear prediction cepstral coefficients are provided to show the generalization capability of our method. A real surveillance system using our algorithm is developed and installed in a metro construction site for real-time recognition performance validation.

  6. 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.

  7. 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.

  8. 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}

  9. Effect of acoustic frequency and power density on the aqueous ultrasonic-assisted extraction of grape pomace (Vitis vinifera L.) - a response surface approach.

    PubMed

    González-Centeno, María Reyes; Knoerzer, Kai; Sabarez, Henry; Simal, Susana; Rosselló, Carmen; Femenia, Antoni

    2014-11-01

    Aqueous ultrasound-assisted extraction (UAE) of grape pomace was investigated by Response Surface Methodology (RSM) to evaluate the effect of acoustic frequency (40, 80, 120kHz), ultrasonic power density (50, 100, 150W/L) and extraction time (5, 15, 25min) on total phenolics, total flavonols and antioxidant capacity. All the process variables showed a significant effect on the aqueous UAE of grape pomace (p<0.05). The Box-Behnken Design (BBD) generated satisfactory mathematical models which accurately explain the behavior of the system; allowing to predict both the extraction yield of phenolic and flavonol compounds, and also the antioxidant capacity of the grape pomace extracts. The optimal UAE conditions for all response factors were a frequency of 40kHz, a power density of 150W/L and 25min of extraction time. Under these conditions, the aqueous UAE would achieve a maximum of 32.31mg GA/100g fw for total phenolics and 2.04mg quercetin/100g fw for total flavonols. Regarding the antioxidant capacity, the maximum predicted values were 53.47 and 43.66mg Trolox/100g fw for CUPRAC and FRAP assays, respectively. When comparing with organic UAE, in the present research, from 12% to 38% of total phenolic bibliographic values were obtained, but using only water as the extraction solvent, and applying lower temperatures and shorter extraction times. To the best of the authors' knowledge, no studies specifically addressing the optimization of both acoustic frequency and power density during aqueous-UAE of plant materials have been previously published.

  10. 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.

  11. Energy Density in Aligned Nanowire Arrays Irradiated with Relativistic Intensities: Path to Terabar Pressure Plasmas

    NASA Astrophysics Data System (ADS)

    Rocca, J.; Bargsten, C.; Hollinger, R.; Shylaptsev, V.; Wang, S.; Rockwood, A.; Wang, Y.; Keiss, D.; Capeluto, M.; Kaymak, V.; Pukhov, A.; Tommasini, R.; London, R.; Park, J.

    2016-10-01

    Ultra-high-energy-density (UHED) plasmas, characterized by energy densities >1 x 108 J cm-3 and pressures greater than a gigabar are encountered in the center of stars and in inertial confinement fusion capsules driven by the world's largest lasers. Similar conditions can be obtained with compact, ultra-high contrast, femtosecond lasers focused to relativistic intensities onto aligned nanowire array targets. Here we report the measurement of the key physical process in determining the energy density deposited in high aspect ratio nanowire array plasmas: the energy penetration. By monitoring the x-ray emission from buried Co tracer segments in Ni nanowire arrays irradiated at an intensity of 4 x 1019 W cm-2, we demonstrate energy penetration depths of several μm, leading to UHED plasmas of that size. Relativistic 3D particle-in-cell-simulations validated by these measurements predict that irradiation of nanostructures at increased intensity will lead to a virtually unexplored extreme UHED plasma regime characterized by energy densities in excess of 8 x 1010 J cm-3, equivalent to a pressure of 0.35 Tbar. This work was supported by the Fusion Energy Program, Office of Science of the U.S Department of Energy, and by the Defense Threat Reduction Agency.

  12. A Patch Density Recommendation based on Convergence Studies for Vehicle Panel Vibration Response resulting from Excitation by a Diffuse Acoustic Field

    NASA Technical Reports Server (NTRS)

    Smith, Andrew; LaVerde, Bruce; Jones, Douglas; Towner, Robert; Waldon, James; Hunt, Ron

    2013-01-01

    Producing fluid structural interaction estimates of panel vibration from an applied pressure field excitation are quite dependent on the spatial correlation of the pressure field. There is a danger of either over estimating a low frequency response or under predicting broad band panel response in the more modally dense bands if the pressure field spatial correlation is not accounted for adequately. It is a useful practice to simulate the spatial correlation of the applied pressure field over a 2d surface using a matrix of small patch area regions on a finite element model (FEM). Use of a fitted function for the spatial correlation between patch centers can result in an error if the choice of patch density is not fine enough to represent the more continuous spatial correlation function throughout the intended frequency range of interest. Several patch density assumptions to approximate the fitted spatial correlation function are first evaluated using both qualitative and quantitative illustrations. The actual response of a typical vehicle panel system FEM is then examined in a convergence study where the patch density assumptions are varied over the same model. The convergence study results illustrate the impacts possible from a poor choice of patch density on the analytical response estimate. The fitted correlation function used in this study represents a diffuse acoustic field (DAF) excitation of the panel to produce vibration response.

  13. A Patch Density Recommendation based on Convergence Studies for Vehicle Panel Vibration Response resulting from Excitation by a Diffuse Acoustic Field

    NASA Technical Reports Server (NTRS)

    Smith, Andrew; LaVerde, Bruce; Jones, Douglas; Towner, Robert; Hunt, Ron

    2013-01-01

    Fluid structural interaction problems that estimate panel vibration from an applied pressure field excitation are quite dependent on the spatial correlation of the pressure field. There is a danger of either over estimating a low frequency response or under predicting broad band panel response in the more modally dense bands if the pressure field spatial correlation is not accounted for adequately. Even when the analyst elects to use a fitted function for the spatial correlation an error may be introduced if the choice of patch density is not fine enough to represent the more continuous spatial correlation function throughout the intended frequency range of interest. Both qualitative and quantitative illustrations evaluating the adequacy of different patch density assumptions to approximate the fitted spatial correlation function are provided. The actual response of a typical vehicle panel system is then evaluated in a convergence study where the patch density assumptions are varied over the same finite element model. The convergence study results are presented illustrating the impact resulting from a poor choice of patch density. The fitted correlation function used in this study represents a Diffuse Acoustic Field (DAF) excitation of the panel to produce vibration response.

  14. New parametrization of Skyrme's interaction for regularized multireference energy density functional calculations

    NASA Astrophysics Data System (ADS)

    Washiyama, K.; Bennaceur, K.; Avez, B.; Bender, M.; Heenen, P.-H.; Hellemans, V.

    2012-11-01

    Background: Symmetry restoration and configuration mixing in the spirit of the generator coordinate method based on energy density functionals have become widely used techniques in low-energy nuclear structure physics. Recently, it has been pointed out that these techniques are ill defined for standard Skyrme functionals, and a regularization procedure has been proposed to remove the resulting spuriosities from such calculations. This procedure imposes an integer power of the density for the density-dependent terms of the functional. At present, only dated parametrizations of the Skyrme interaction fulfill this condition.Purpose: To construct a set of parametrizations of the Skyrme energy density functional for multireference energy density functional calculations with regularization using the state-of-the-art fitting protocols.Method: The parametrizations were adjusted to reproduce ground-state properties of a selected set of doubly magic nuclei and properties of nuclear matter. Subsequently, these parameter sets were validated against properties of spherical and deformed nuclei.Results: Our parameter sets successfully reproduce the experimental binding energies and charge radii for a wide range of singly magic nuclei. Compared to the widely used SLy5 and to the SIII parametrization that has integer powers of the density, a significant improvement of the reproduction of the data is observed. Similarly, a good description of the deformation properties at A˜80 was obtained.Conclusions: We have constructed new Skyrme parametrizations with integer powers of the density and validated them against a broad set of experimental data for spherical and deformed nuclei. These parametrizations are tailor-made for regularized multireference energy density functional calculations and can be used to study correlations beyond the mean field in atomic nuclei.

  15. Band offset formation at semiconductor heterojunctions through density-based minimization of interface energy

    NASA Astrophysics Data System (ADS)

    Tung, Raymond T.; Kronik, Leeor

    2016-08-01

    It is well known that the magnitude of band offset (BO) at any semiconductor heterojunction is directly derivable from the distribution of charge at that interface and that the latter is decided by a minimization of total energy. However, the fact that BO formation is governed by energy minimization has not been explicitly used in theoretical BO models, likely because the equilibrium charge densities at heterojunction interfaces appear difficult to predict, except via explicit calculation. In this paper, electron densities at a large number of (100), (110), and (111) oriented heterojunctions between lattice-matched, isovalent semiconductors with the zinc blende (ZB) structure have been calculated by first-principles methods and analyzed in detail for possible common characteristics among energy-minimized densities. Remarkably, the heterojunction electron density was found to largely depend only on the immediate, local atomic arrangement. In fact, it is so much so that a juxtaposition of local electron-densities generated in oligo-cells (LEGOs) accurately reproduced the charge densities that minimize the energy for the heterojunctions. Furthermore, the charge distribution for each bulk semiconductor was found to display a striking separability of its electrostatic effect into two neutral parts, associated with the cation and the anion, which are approximately transferrable among semiconductors. These discoveries form the basis of a neutral polyhedra theory (NPT) that approximately predicts the equilibrium charge density and BO of relaxed heterojunctions from the energy minimization requirement. Well-known experimentally observed characteristics of heterojunctions, such as the insensitivity of BO to heterojunction orientation and the identity of interface bonds, the transitivity rule, etc., are all in good agreement with the NPT. Therefore, energy minimization, which essentially decides the electronic properties of all other solid and molecular systems, also governs

  16. 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

  17. 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

    2015-02-24

    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.

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

    PubMed

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

    2013-09-01

    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.

  19. The National Ignition Facility and the Golden Age of High Energy Density Science

    SciTech Connect

    Meier, W; Moses, E I; Newton, M

    2007-09-27

    The National Ignition Facility (NIF) is a 192-beam Nd:glass laser facility being constructed at the Lawrence Livermore National Laboratory (LLNL) to conduct research in inertial confinement fusion (ICF) and high energy density (HED) science. When completed, NIF will produce 1.8 MJ, 500 TW of ultraviolet light, making it the world's largest and highest-energy laser system. The NIF is poised to become the world's preeminent facility for conducting ICF and fusion energy research and for studying matter at extreme densities and temperatures.

  20. The National Ignition Facility and the Golden Age of High Energy Density Science

    SciTech Connect

    Moses, E

    2007-08-14

    The National Ignition Facility (NIF) is a 192-beam Nd:glass laser facility being constructed at the Lawrence Livermore National Laboratory (LLNL) to conduct research in inertial confinement fusion (ICF) and high energy density (HED) science. When completed, NIF will produce 1.8 MJ, 500 TW of ultraviolet light, making it the world's largest and highest-energy laser system. The NIF is poised to become the world's preeminent facility for conducting ICF and fusion energy research and for studying matter at extreme densities and temperatures.

  1. 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.

  2. Low frequency acoustic microscope

    DOEpatents

    Khuri-Yakub, Butrus T.

    1986-11-04

    A scanning acoustic microscope is disclosed for the detection and location of near surface flaws, inclusions or voids in a solid sample material. A focused beam of acoustic energy is directed at the sample with its focal plane at the subsurface flaw, inclusion or void location. The sample is scanned with the beam. Detected acoustic energy specularly reflected and mode converted at the surface of the sample and acoustic energy reflected by subsurface flaws, inclusions or voids at the focal plane are used for generating an interference signal which is processed and forms a signal indicative of the subsurface flaws, inclusions or voids.

  3. Azobenzene-functionalized carbon nanotubes as high-energy density solar thermal fuels.

    PubMed

    Kolpak, Alexie M; Grossman, Jeffrey C

    2011-08-10

    Solar thermal fuels, which reversibly store solar energy in molecular bonds, are a tantalizing prospect for clean, renewable, and transportable energy conversion/storage. However, large-scale adoption requires enhanced energy storage capacity and thermal stability. Here we present a novel solar thermal fuel, composed of azobenzene-functionalized carbon nanotubes, with the volumetric energy density of Li-ion batteries. Our work also demonstrates that the inclusion of nanoscale templates is an effective strategy for design of highly cyclable, thermally stable, and energy-dense solar thermal fuels.

  4. Path analysis of the energy density of wood in eucalyptus clones.

    PubMed

    Couto, A M; Teodoro, P E; Trugilho, P F

    2017-03-16

    Path analysis has been used for establishing selection criteria in genetic breeding programs for several crops. However, it has not been used in eucalyptus breeding programs yet. In the present study, we aimed to identify the wood technology traits that could be used as the criteria for direct and indirect selection of eucalyptus genotypes with high energy density of wood. Twenty-four eucalyptus clones were evaluated in a completely randomized design with five replications. The following traits were assessed: basic wood density, total extractives, lignin content, ash content, nitrogen content, carbon content, hydrogen content, sulfur content, oxygen content, higher calorific power, holocellulose, and energy density. After verifying the variability of all evaluated traits among the clones, a two-dimensional correlation network was used to determine the phenotypic patterns among them. The obtained coefficient of determination (0.94) presented a higher magnitude in relation to the effect of the residual variable, and it served as an excellent model for explaining the genetic effects related to the variations observed in the energy density of wood in all eucalyptus clones. However, for future studies, we recommend evaluating other traits, especially the morphological traits, because of the greater ease in their measurement. Selecting clones with high basic density is the most promising strategy for eucalyptus breeding programs that aim to increase the energy density of wood because of its high heritability and magnitude of the cause-and-effect relationship with this trait.

  5. Changes in irradiance and energy density in relation to different curing distances.

    PubMed

    Beolchi, Rafael Silva; Moura-Netto, Cacio; Palo, Renato Miotto; Rocha Gomes Torres, Carlos; Pelissier, Bruno

    2015-01-01

    The present study aimed to assess the influence of curing distance on the loss of irradiance and power density of four curing light devices. The behavior in terms of power density of four different dental curing devices was analyzed (Valo, Elipar 2, Radii-Cal, and Optilux-401) using three different distances of photopolymerization (0 mm, 4 mm, and 8 mm). All devices had their power density measured using a MARC simulator. Ten measurements were made per device at each distance. The total amount of energy delivered and the required curing time to achieve 16 J/cm(2) of energy was also calculated. Data were statistically analyzed with one-way analysis of variance and Tukey's tests (p < 0.05). The curing distance significantly interfered with the loss of power density for all curing light devices, with the farthest distance generating the lowest power density and consequently the longer time to achieve an energy density of 16 J/cm(2) (p < 0.01). Comparison of devices showed that Valo, in extra power mode, showed the best results at all distances, followed by Valo in high power mode, Valo in standard mode, Elipar 2, Radii-Cal, and Optilux-401 halogen lamp (p < 0.01). These findings indicate that all curing lights induced a significant loss of irradiance and total energy when the light was emitted farther from the probe. The Valo device in extra power mode showed the highest power density and the shortest time to achieve an energy density of 16 J/cm(2) at all curing distances.

  6. Energy flux density and angular momentum density of Pearcey-Gauss vortex beams in the far field

    NASA Astrophysics Data System (ADS)

    Cheng, K.; Lu, G.; Zhong, X.

    2017-02-01

    The longitudinal and transverse energy flux density (EFD) and angular momentum density (AMD) of a Pearcey-Gauss vortex beam in the far field are studied using the vector angular spectrum representation and stationary phase method, where the influence of topological charge, noncanonical strength and off-axis distance of the embedded optical vortex on far-field vectorial structures of the corresponding beam is emphasized. For comparison, the EFD and AMD of the Pearcey-Gauss beam with non-vortex in the far field are also discussed. The results show that the longitudinal EFDs of the Pearcey-Gauss vortex beam exhibit parabolic patterns, and the number of parabolic dark zones equals the absolute value of topological charge of the embedded optical vortex in the input plane. While for the Pearcey-Gauss beam, the dark zones are not found owing to the non-vortex in the input plane. The motion of zero-intensity spot of whole beam appears by varying the off-axis distance. Noncanonical strength and off-axis distance both can adjust the magnitudes and directions of transverse EFD and control the spatial energy distributions of longitudinal EFD, but not change the net AMD.

  7. Density-Functional Theory Studies of Correlation Energy Effects at Metallic Surfaces.

    NASA Astrophysics Data System (ADS)

    Mohammed, Abdel-Raouf Eid

    In this thesis we study the effects of correlation in the inhomogeneous electron gas at metallic surfaces. These studies are performed within the context of density-functional theory (DFT). Using accurate representations of the electronic density profile, we have estimated variationally the surface correlation energy of jellium metal. The accuracy of these estimates is founded in the assumption that the exchange -correlation energy functional of the density is approximated accurately by the wave-vector analysis method, and by the fact that the non-local exchange energy contributions are treated exactly. In contrast to the previously accepted conclusion that for surfaces correlation effects are as significant as exchange, our results indicate the ratio of these energies to lie between 34% - 97% over the metallic density range, the smaller ratios corresponding to the higher density metals. In this work we have also examined the local density (LDA) and gradient expansion approximations (GEA) (to O((DEL)('2))) for the correlation energy. We have demonstrated for realistic metal surface densities the cancellation of the errors in the LDA for exchange and correlation, and shown that the density profiles at surfaces would have to be unphysically slowly varying for the correlation energy GEA to converge. We have also studied the effects of correlation at surfaces by screening the exchange, and observe that the surface exchange energy for screened-Coulomb interaction decreases as the screening length is reduced. Thus, the more short-ranged the interaction, the easier it is to split the crystal in two. In addition we have derived the DFT first gradient correction coefficient in the GEA for the screened-Coulomb exchange energy, and shown it to be the same as that obtained within Hartree -Fock theory (HFT) for finite screening. This coefficient reduces to the DFT bare-Coulomb interaction value in the limit of no screening in which limit the HFT coefficient is singular. The GEA

  8. 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

    2014-05-06

    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

  9. 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

    2016-04-20

    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.

  10. 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

  11. 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

  12. Flexible asymmetric supercapacitors with high energy and high power density in aqueous electrolytes.

    PubMed

    Cheng, Yingwen; Zhang, Hongbo; Lu, Songtao; Varanasi, Chakrapani V; Liu, Jie

    2013-02-07

    Supercapacitors with both high energy and high power densities are critical for many practical applications. In this paper, we discuss the design and demonstrate the fabrication of flexible asymmetric supercapacitors based on nanocomposite electrodes of MnO(2), activated carbon, carbon nanotubes and graphene. The combined unique properties of each of these components enable highly flexible and mechanically strong films that can serve as electrodes directly without using any current collectors or binders. Using these flexible electrodes and a roll-up approach, asymmetric supercapacitors with 2 V working voltage were successfully fabricated. The fabricated device showed excellent rate capability, with 78% of the original capacitance retained when the scan rate was increased from 2 mV s(-1) to 500 mV s(-1). Owing to the unique composite structure, these supercapacitors were able to deliver high energy density (24 W h kg(-1)) under high power density (7.8 kW kg(-1)) conditions. These features could enable supercapacitor based energy storage systems to be very attractive for a variety of critical applications, such as the power sources in hybrid electric vehicles and the back-up powers for wind and solar energy, where both high energy density and high power density are required.

  13. 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.

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

    PubMed

    Dash, Ranjan; Pannala, Sreekanth

    2016-06-17

    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.

  15. Device and method for generating a beam of acoustic energy from a borehole, and applications thereof

    DOEpatents

    Vu, Cung Khac; Sinha, Dipen N.; Pantea, Cristian; Nihei, Kurt; Schmitt, Denis P.; Skelt, Christopher

    2010-11-23

    In some aspects of the invention, a device, positioned within a well bore, configured to generate and direct an acoustic beam into a rock formation around a borehole is disclosed. The device comprises a source configured to generate a first signal at a first frequency and a second signal at a second frequency; a transducer configured to receive the generated first and the second signals and produce acoustic waves at the first frequency and the second frequency; and a non-linear material, coupled to the transducer, configured to generate a collimated beam with a frequency equal to the difference between the first frequency and the second frequency by a non-linear mixing process, wherein the non-linear material includes one or more of a mixture of liquids, a solid, a granular material, embedded microspheres, or an emulsion.

  16. System for generating a beam of acoustic energy from a borehole, and applications thereof

    DOEpatents

    Vu, Cung Khac [Houston, TX; Sinha, Dipen N [Los Alamos, NM; Pantea, Cristian [Los Alamos, NM; Nihei, Kurt T [Oakland, CA; Schmitt, Denis P [Katy, TX; Skelt, Christopher [Houston, TX

    2012-07-31

    In some aspects of the invention, a device, positioned within a well bore, configured to generate and direct an acoustic beam into a rock formation around a borehole is disclosed. The device comprises a source configured to generate a first signal at a first frequency and a second signal at a second frequency; a transducer configured to receive the generated first and the second signals and produce acoustic waves at the first frequency and the second frequency; and a non-linear material, coupled to the transducer, configured to generate a collimated beam with a frequency equal to the difference between the first frequency and the second frequency by a non-linear mixing process, wherein the non-linear material includes one or more of a mixture of liquids, a solid, a granular material, embedded microspheres, or an emulsion.

  17. System for generating a beam of acoustic energy from a borehole, and applications thereof

    DOEpatents

    Vu, Cung Khac; Sinha, Dipen N.; Pantea, Cristian; Nihei, Kurt T.; Schmitt, Denis P.; Skelt, Christopher

    2012-09-04

    In some aspects of the invention, a device, positioned within a well bore, configured to generate and direct an acoustic beam into a rock formation around a borehole is disclosed. The device comprises a source configured to generate a first signal at a first frequency and a second signal at a second frequency; a transducer configured to receive the generated first and the second signals and produce acoustic waves at the first frequency and the second frequency; and a non-linear material, coupled to the transducer, configured to generate a collimated beam with a frequency equal to the difference between the first frequency and the second frequency by a non-linear mixing process, wherein the non-linear material includes one or more of a mixture of liquids, a solid, a granular material, embedded microspheres, or an emulsion.

  18. Dietary energy density but not glycemic load is associated with gestational weight gain

    PubMed Central

    Deierlein, Andrea L.; Siega-Riz, Anna Maria; Herring, Amy

    2009-01-01

    Background The majority of pregnant women are gaining outside of the recommended weight gain ranges. Excessive weight gains have been linked to pregnancy complications and long term maternal and child health outcomes. Objective To examine the impact of dietary glycemic load and energy density on total gestational weight gain and weight gain ratio (observed weight gain/expected weight gain). Design Data are from 1231 women with singleton pregnancies who participated in the Pregnancy, Infection, and Nutrition Cohort Study. Dietary information was collected at 26–29 weeks gestation using a semi-quantified food frequency questionnaire. Linear regression models were used to estimate the associations between glycemic load (in quartiles) and energy density (in quartiles) with total gestational weight gain and weight gain ratio. Results Dietary patterns of pregnant women significantly differed across many sociodemographic and behavioral characteristics, with the greatest contrasts seen for glycemic load. After adjustment for covariates, in comparison to women in the first quartile, consuming a mean dietary energy density of 0.77 kcal/g (reference), women in the second quartile, consuming a mean energy density of 0.95 kcal/g, gained an excess of 0.91 kg (95% CI: 0.02–1.79) and women in the third quartile, consuming a mean energy density of 1.09 kcal/g, gained an excess of 1.47 kg (95% CI: 0.58–2.36). All other comparisons of energy intakes were not statistically significant. Glycemic load was not associated with total gestational weight gain or weight gain ratio. Conclusions Dietary energy density is a modifiable factor that may assist pregnant women in managing gestational weight gains. PMID:18779285

  19. Estimating food portions. Influence of unit number, meal type and energy density.

    PubMed

    Almiron-Roig, Eva; Solis-Trapala, Ivonne; Dodd, Jessica; Jebb, Susan A

    2013-12-01

    Estimating how much is appropriate to consume can be difficult, especially for foods presented in multiple units, those with ambiguous energy content and for snacks. This study tested the hypothesis that the number of units (single vs. multi-unit), meal type and food energy density disrupts accurate estimates of portion size. Thirty-two healthy weight men and women attended the laboratory on 3 separate occasions to assess the number of portions contained in 33 foods or beverages of varying energy density (1.7-26.8 kJ/g). Items included 12 multi-unit and 21 single unit foods; 13 were labelled "meal", 4 "drink" and 16 "snack". Departures in portion estimates from reference amounts were analysed with negative binomial regression. Overall participants tended to underestimate the number of portions displayed. Males showed greater errors in estimation than females (p=0.01). Single unit foods and those labelled as 'meal' or 'beverage' were estimated with greater error than multi-unit and 'snack' foods (p=0.02 and p<0.001 respectively). The number of portions of high energy density foods was overestimated while the number of portions of beverages and medium energy density foods were underestimated by 30-46%. In conclusion, participants tended to underestimate the reference portion size for a range of food and beverages, especially single unit foods and foods of low energy density and, unexpectedly, overestimated the reference portion of high energy density items. There is a need for better consumer education of appropriate portion sizes to aid adherence to a healthy diet.

  20. High-energy ion generation in interaction. of short laser pulse with high-density plasma

    NASA Astrophysics Data System (ADS)

    Sentoku, Y.; Bychenkov, V. Y.; Flippo, K.; Maksimchuk, A.; Mima, K.; Mourou, G.; Sheng, Z. M.; Umstadter, D.

    2002-03-01

    Multi-MeV ion production from the interaction of a short laser pulse with a high-density plasma, accompanied by an underdense preplasma, has been studied with a particle-in-cell simulation and good agreement is found with experiment. The mechanism primarily responsible for the acceleration of ions is identified. Comparison with experiments sheds light on the ion-energy dependence on laser intensity, preplasma scale length, and relative ion energies for a multi-species plasma. Two regimes of maximum ion-energy dependence on laser intensity, I, have been identified: subrelativistic, ∝I; and relativistic, ∝. Simulations show that the energy of the accelerated ions versus the preplasma scale length increases linearly and then saturates. In contrast, the ion energy decreases with the thickness of the solid-density plasma.

  1. 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.

  2. Excitation energy dependence of the level density parameter close to the doubly magic 208Pb

    NASA Astrophysics Data System (ADS)

    Roy, Pratap; Banerjee, K.; Bhattacharya, C.; Pandey, R.; Sen, A.; Manna, S.; Kundu, S.; Rana, T. K.; Ghosh, T. K.; Mukherjee, G.; Roy, T.; Dhal, A.; Dey, A.; Meena, J. K.; Saha, A. K.; Pandit, Deepak; Mukhopadhyay, S.; Bhattacharya, S.

    2016-12-01

    Neutron evaporation spectra have been measured from 4He+208Pb and 4He+209Bi reactions by using 4He-ion beams of several bombarding energies. Excitation-energy dependence of the level density parameter has been studied for the two systems in the excitation energy range of ˜18 -50 MeV. For both the reactions an overall reduction of the asymptotic level density parameter with increasing excitation energy (temperature) is observed. The trend of the data was compared with the Thomas-Fermi model predictions and found to be in reasonable agreement. The value of the shell damping parameter has been extracted from the lowest-energy data in the case of Po,211210 and At,212211 nuclei close to the Z =82 and N =126 shell closure, and it was found to be consistent with the recent measurement in the vicinity of doubly magic 208Pb nucleus.

  3. Density-functional correction of random-phase-approximation correlation with results for jellium surface energies

    NASA Astrophysics Data System (ADS)

    Kurth, Stefan; Perdew, John P.

    1999-04-01

    Since long-range electron-electron correlation is treated properly in the random phase approximation (RPA), we define short-range correlation as the correction to the RPA. The effects of short-range correlation are investigated here in the local spin density (LSD) approximation and the generalized gradient approximation (GGA). Results are presented for atoms, molecules, and jellium surfaces. It is found that (1) short-range correlation energies are less sensitive to the inclusion of density gradients than are full correlation energies, and (2) short-range correlation makes a surprisingly small contribution to surface and molecular atomization energies. In order to improve the accuracy of electronic-structure calculations, we therefore combine a GGA treatment of short-range correlation with a full RPA treatment of the exchange-correlation energy. This approach leads to jellium surface energies close to those of the LSD approximation for exchange and correlation together (but not for each separately).

  4. Density slope of the symmetry energy L (ρ0) constrained by proton radioactivity

    NASA Astrophysics Data System (ADS)

    Wan, Niu; Xu, Chang; Ren, Zhongzhou

    2016-10-01

    Background: Recently, the cluster radioactivity of heavy nuclei decaying to 208Pb was successfully used to constrain the density slope of the symmetry energy L (ρ0) at saturation density ρ0. Purpose: By using well-measured experimental decay energy and half-life, proton radioactivity is proposed to further constrain L (ρ0) in this work. Method: From the Hugenholtz-Van Hove theorem, L (ρ0) is found to be directly related to the magnitude of the symmetry potential, which can be extracted from the proton radioactivity within the density-dependent cluster model. Results: By investigating the radioactivity of proton emitters with large isospin asymmetry, the value of the density slope is found to be L (ρ0)=51.8 ±7.2 MeV.

  5. 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.

  6. 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.

  7. 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.

  8. Electromagnetic reflection, transmission, and energy density at boundaries of nonlocal media

    NASA Astrophysics Data System (ADS)

    Churchill, R. J.; Philbin, T. G.

    2016-12-01

    We consider a semi-infinite spatially dispersive dielectric with unequal transverse and longitudinal susceptibilities. The effect of the boundary is characterized by arbitrary reflection coefficients for polarization waves in the material that propagate to the surface. Specific values of these coefficients correspond to various additional boundary conditions (ABCs) for Maxwell's equations. We derive the electromagnetic reflection and transmission coefficients at the boundary and investigate their dependence on material parameters and ABCs. We also investigate the electromagnetic zero-point and thermal spectral energy density outside the dielectric. The nonlocal response removes the boundary divergence of the spectral energy density that is present in a local model. The spectral energy density shows a large dependence on the difference between the transverse and longitudinal susceptibilities, even at distances up to 10 nm from the boundary.

  9. Boosting the Energy Density of Carbon-Based Aqueous Supercapacitors by Optimizing the Surface Charge.

    PubMed

    Yu, Minghao; Lin, Dun; Feng, Haobin; Zeng, Yinxiang; Tong, Yexiang; Lu, Xihong

    2017-03-27

    The voltage of carbon-based aqueous supercapacitors is limited by the water splitting reaction occurring in one electrode, generally resulting in the promising but unused potential range of the other electrode. Exploiting this unused potential range provides the possibility for further boosting their energy density. An efficient surface charge control strategy was developed to remarkably enhance the energy density of multiscale porous carbon (MSPC) based aqueous symmetric supercapacitors (SSCs) by controllably tuning the operating potential range of MSPC electrodes. The operating voltage of the SSCs with neutral electrolyte was significantly expanded from 1.4 V to 1.8 V after simple adjustment, enabling the energy density of the optimized SSCs reached twice as much as the original. Such a facile strategy was also demonstrated for the aqueous SSCs with acidic and alkaline electrolytes, and is believed to bring insight in the design of aqueous supercapacitors.

  10. Kinetic Energy of Hydrocarbons as a Function of Electron Density and Convolutional Neural Networks.

    PubMed

    Yao, Kun; Parkhill, John

    2016-03-08

    We demonstrate a convolutional neural network trained to reproduce the Kohn-Sham kinetic energy of hydrocarbons from an input electron density. The output of the network is used as a nonlocal correction to conventional local and semilocal kinetic functionals. We show that this approximation qualitatively reproduces Kohn-Sham potential energy surfaces when used with conventional exchange correlation functionals. The density which minimizes the total energy given by the functional is examined in detail. We identify several avenues to improve on this exploratory work, by reducing numerical noise and changing the structure of our functional. Finally we examine the features in the density learned by the neural network to anticipate the prospects of generalizing these models.

  11. Density distribution of high energy electrons in pulsed corona discharge of NO+N2 mixture.

    PubMed

    Wang, Wenchun; Liu, Feng; Zhang, Jialiang; Wang, Younian

    2003-12-01

    Emission spectroscopy of the high-voltage pulsed positive corona discharge in a line-cylinder reactor is used to investigate the high-energy electron density distribution in the discharge gap. The relative overall emission intensity spatial distribution profile of the A2Sigma+ --> X2Pi transition of NO is successfully recorded against a severe electromagnetic pulse interference coming from the corona discharge at one atmosphere. The spectroscopic investigation shows that the high-energy electron density in the discharge has a nonlinearly decline in the radial distribution. When varying the discharge voltage, the absolute emission intensity of NO is different but the radial distribution profile is similar. If an oxygen flow was introduced into the discharge reactor, the emission intensity of NO decreases tremendously and, therefore, the high-energy electron density decreases reasonably.

  12. Energy spectrometry of electrons ejected from dynamic quantum dots driven up a potential slope by a surface acoustic wave

    NASA Astrophysics Data System (ADS)

    Ford, Christopher; Benesh, Matthew; Son, Seok-Kyun; Kataoka, Masaya; Barnes, Crispin; McNeil, Robert; Griffiths, Jon; Jones, Geb; Farrer, Ian; Ritchie, David

    2013-03-01

    Surface acoustic waves (SAWs) in a GaAs/AlGaAs heterostructure generate an electrostatic wave which propagates at the sound velocity. This potential wave is capable of collecting electrons from a 2D electron gas (2DEG) and transporting them through a depleted channel. The SAW minima form a continuous series of dynamic quantum dots, each transporting a controllable number of electrons along the channel. The confinement of the electrons in each dot increases as the potential rises along the channel, ejecting electrons one-by-one back into the 2DEG above the Fermi energy. These electrons can travel several microns before thermalising. We measure their energy spectrum using a variable potential barrier upstream as the channel is squeezed by split gates, and correlate this with the SAW-driven current along the channel. Now at RWTH Aachen

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

    PubMed Central

    Ducote, Justin L.; Molloi, Sabee

    2010-01-01

    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 μm rhodium beam filter for low energy images and a 300 μm 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 cm2, 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%. PMID:20229889

  14. 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

  15. 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.

  16. 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

  17. Gravitational Energy-Momentum Density in Bianchi Type II Space-Times

    NASA Astrophysics Data System (ADS)

    Aydogdu, Oktay

    In this paper, using Einstein, Landau and Lifshitz's energy-momentum complexes both in general relativity and teleparallel gravity, we calculate the total energy distribution (due to matter and fields, including gravitation) associated with locally rotationally symmetric (LRS) Bianchi type II cosmological models. We show that energy densities in these different gravitation theories are the same, so they agree with each other. We obtain the result that the total energy is zero. This result agrees with previous works of Cooperstock and Israelit, Rosen, Johri et al., Banerjee and Sen, Vargas, Aydogdu and Saltı. Moreover, our result supports the viewpoints of Albrow and Tryon.

  18. Application of a high-energy-density permanent magnet material in underwater systems

    NASA Astrophysics Data System (ADS)

    Cho, C. P.; Egan, C.; Krol, W. P.

    1996-06-01

    This paper addresses the application of high-energy-density permanent magnet (PM) technology to (1) the brushless, axial-field PM motor and (2) the integrated electric motor/pump system for under-water applications. Finite-element analysis and lumped parameter magnetic circuit analysis were used to calculate motor parameters and performance characteristics and to conduct tradeoff studies. Compact, efficient, reliable, and quiet underwater systems are attainable with the development of high-energy-density PM material, power electronic devices, and power integrated-circuit technology.

  19. Determination of the area density and composition of alloy film using dual alpha particle energy loss

    NASA Astrophysics Data System (ADS)

    Ma, Xiaojun; Li, Bo; Gao, Dangzhong; Xu, Jiayun; Tang, Yongjian

    2017-02-01

    A novel method based on dual α-particles energy loss (DAEL) is proposed for measuring the area density and composition of binary alloy films. In order to obtain a dual-energy α-particles source, an ingenious design that utilizes the transmitted α-particles traveling the thin film as a new α-particles source is presented. Using the DAEL technique, the area density and composition of Au/Cu film are determined accurately with an uncertainty of better than 10%. Finally, some measures for improving the combined uncertainty are discussed.

  20. 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.

  1. Fragmentation in isotopic and isobaric systems as probe of density dependence of nuclear symmetry energy

    NASA Astrophysics Data System (ADS)

    Kaur, Mandeep; Gautam, Sakshi; Puri, Rajeev K.

    2016-11-01

    We probe the density-dependent behavior of symmetry energy using the yield of various fragments in central collisions of various isotopic and isobaric colliding pairs. We calculate the yields of free nucleons, light charged particles and intermediate mass fragments in neutron-rich colliding systems as well as the ratio of relative yields of above fragments and free nucleons. Our findings reveal that the ratio of relative yield of light charged particles poses better candidate to probe the density dependence of nuclear symmetry energy.

  2. 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.

  3. 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.

  4. Extra-metabolic energy use and the rise in human hyper-density

    NASA Astrophysics Data System (ADS)

    Burger, Joseph R.; Weinberger, Vanessa P.; Marquet, Pablo A.

    2017-03-01

    Humans, like all organisms, are subject to fundamental biophysical laws. Van Valen predicted that, because of zero-sum dynamics, all populations of all species in a given environment flux the same amount of energy on average. Damuth’s ’energetic equivalence rule’ supported Van Valen´s conjecture by showing a tradeoff between few big animals per area with high individual metabolic rates compared to abundant small species with low energy requirements. We use metabolic scaling theory to compare variation in densities and individual energy use in human societies to other land mammals. We show that hunter-gatherers occurred at densities lower than the average for a mammal of our size. Most modern humans, in contrast, concentrate in large cities at densities up to four orders of magnitude greater than hunter-gatherers, yet consume up to two orders of magnitude more energy per capita. Today, cities across the globe flux greater energy than net primary productivity on a per area basis. This is possible by importing enormous amounts of energy and materials required to sustain hyper-dense, modern humans. The metabolic rift with nature created by modern cities fueled largely by fossil energy poses formidable challenges for establishing a sustainable relationship on a rapidly urbanizing, yet finite planet.

  5. Study of low energy density photovoltaic applications under varying rate structures

    NASA Astrophysics Data System (ADS)

    Parker, C. D.

    1984-09-01

    A study to identify and rank low energy density photovoltaic applications and to do detailed analyses and tradeoff studies of the best applications was completed. Low energy density applications are those with peak power requirements of 60 Wp/sq m of floor space, or less, and a commensurate total daytime energy consumption. Four locations for the PV applications, one to represent each of the four geographic regions of the United States were specified. Existing energy consumption data bases and building inventories were studied to identify and rank low energy density applications. Four applications were identified; a branch bank, a day care center, an automotive service center, and distributor warehouse. The 16 application/site pairs were examined. Conceptual designs were generated for each and hour-by-hour energy requirements for typical year for each application/site pair were determined. A PV system was specified for each building at each site, and the performance of each PV system in meeting the building load in the same typical year was determined. The economics of each application was evaluated for a range of on and off peak rates for backup energy and for a range of sellback ratios.

  6. Extra-metabolic energy use and the rise in human hyper-density.

    PubMed

    Burger, Joseph R; Weinberger, Vanessa P; Marquet, Pablo A

    2017-03-02

    Humans, like all organisms, are subject to fundamental biophysical laws. Van Valen predicted that, because of zero-sum dynamics, all populations of all species in a given environment flux the same amount of energy on average. Damuth's 'energetic equivalence rule' supported Van Valen´s conjecture by showing a tradeoff between few big animals per area with high individual metabolic rates compared to abundant small species with low energy requirements. We use metabolic scaling theory to compare variation in densities and individual energy use in human societies to other land mammals. We show that hunter-gatherers occurred at densities lower than the average for a mammal of our size. Most modern humans, in contrast, concentrate in large cities at densities up to four orders of magnitude greater than hunter-gatherers, yet consume up to two orders of magnitude more energy per capita. Today, cities across the globe flux greater energy than net primary productivity on a per area basis. This is possible by importing enormous amounts of energy and materials required to sustain hyper-dense, modern humans. The metabolic rift with nature created by modern cities fueled largely by fossil energy poses formidable challenges for establishing a sustainable relationship on a rapidly urbanizing, yet finite planet.

  7. Extra-metabolic energy use and the rise in human hyper-density

    PubMed Central

    Burger, Joseph R.; Weinberger, Vanessa P.; Marquet, Pablo A.

    2017-01-01

    Humans, like all organisms, are subject to fundamental biophysical laws. Van Valen predicted that, because of zero-sum dynamics, all populations of all species in a given environment flux the same amount of energy on average. Damuth’s ’energetic equivalence rule’ supported Van Valen´s conjecture by showing a tradeoff between few big animals per area with high individual metabolic rates compared to abundant small species with low energy requirements. We use metabolic scaling theory to compare variation in densities and individual energy use in human societies to other land mammals. We show that hunter-gatherers occurred at densities lower than the average for a mammal of our size. Most modern humans, in contrast, concentrate in large cities at densities up to four orders of magnitude greater than hunter-gatherers, yet consume up to two orders of magnitude more energy per capita. Today, cities across the globe flux greater energy than net primary productivity on a per area basis. This is possible by importing enormous amounts of energy and materials required to sustain hyper-dense, modern humans. The metabolic rift with nature created by modern cities fueled largely by fossil energy poses formidable challenges for establishing a sustainable relationship on a rapidly urbanizing, yet finite planet. PMID:28252010

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

    SciTech Connect

    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 an intermediate temperature could greatly benefit this traditional energy storage technology by improving battery energy density, cycle life and reducing material costs.

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

    DOE PAGES

    Li, Guosheng; Lu, Xiaochuan; Kim, Jin Yong; ...

    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

  10. Magnetomechanical coupling factor and energy density of single crystal iron-gallium alloys

    NASA Astrophysics Data System (ADS)

    Datta, Supratik; Flatau, Alison B.

    2008-03-01

    Energy density and coupling factor are widely used as figures of merit for comparing different active materials. These parameters are usually evaluated as material constants assuming a linear behavior of the material over all operating ranges. In this work it is shown that the operating conditions have an effect on the energy density and coupling factor which cannot be ignored. A single crystal rod of Fe 84Ga 16 was characterized as a magnetostrictive actuator and sensor under different quasi-static stress and magnetic field conditions. The material showed a saturation magnetostriction of 247 μɛ and a maximum stress sensitivity of 45 T/GPa. A maximum energy density of 2.38 kJ/m 3 and coupling factor higher than 0.6 were calculated from experimental results. The experimental behavior was modeled using an energy based non-linear approach which was further used to calculate the coupling factor and energy density as continuous functions of stress and magnetic field in the material. Guidelines on optimal operating conditions for magnetostrictive actuators and sensors using FeGa alloys have been suggested.

  11. [Cost and energy density of diet in Brazil, 2008-2009].

    PubMed

    Ricardo, Camila Zancheta; Claro, Rafael Moreira

    2012-12-01

    This study aimed to evaluate the relationship between the cost and energy density of diet consumed in Brazilian households. Data from the Brazilian Household Budget Survey (POF 2008/2009) were used to identify the main foods and their prices. Similar items were grouped, resulting in a basket of 67 products. Linear programming was applied for the composition of isoenergetic baskets, minimizing the deviation from the average household diet. Restrictions were imposed on the inclusion of items and the energy contribution of the various food groups. A reduction in average cost of diet was applied at intervals of R$0.15 to the lowest possible cost. We identified an inverse association between energy density and cost of diet (p < 0.05), and at the lowest possible cost we obtained the maximum value of energy density. Restrictions on the diet's cost resulted in the selection of diets with higher energy density, indicating that cost of diet may lead to the adoption of inadequate diets in Brazil.

  12. 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

  13. The WiggleZ Dark Energy Survey: testing the cosmological model with baryon acoustic oscillations at z= 0.6

    NASA Astrophysics Data System (ADS)

    Blake, Chris; Davis, Tamara; Poole, Gregory B.; Parkinson, David; Brough, Sarah; Colless, Matthew; Contreras, Carlos; Couch, Warrick; Croom, Scott; Drinkwater, Michael J.; Forster, Karl; Gilbank, David; Gladders, Mike; Glazebrook, Karl; Jelliffe, Ben; Jurek, Russell J.; Li, I.-Hui; Madore, Barry; Martin, D. Christopher; Pimbblet, Kevin; Pracy, Michael; Sharp, Rob; Wisnioski, Emily; Woods, David; Wyder, Ted K.; Yee, H. K. C.

    2011-08-01

    We measure the imprint of baryon acoustic oscillations (BAOs) in the galaxy clustering pattern at the highest redshift achieved to date, z= 0.6, using the distribution of N= 132 509 emission-line galaxies in the WiggleZ Dark Energy Survey. We quantify BAOs using three statistics: the galaxy correlation function, power spectrum and the band-filtered estimator introduced by Xu et al. The results are mutually consistent, corresponding to a 4.0 per cent measurement of the cosmic distance-redshift relation at z= 0.6 [in terms of the acoustic parameter 'A(z)' introduced by Eisenstein et al., we find A(z= 0.6) = 0.452 ± 0.018]. Both BAOs and power spectrum shape information contribute towards these constraints. The statistical significance of the detection of the acoustic peak in the correlation function, relative to a wiggle-free model, is 3.2σ. The ratios of our distance measurements to those obtained using BAOs in the distribution of luminous red galaxies at redshifts z= 0.2 and 0.35 are consistent with a flat Λ cold dark matter model that also provides a good fit to the pattern of observed fluctuations in the cosmic microwave background radiation. The addition of the current WiggleZ data results in a ≈30 per cent improvement in the measurement accuracy of a constant equation of state, w, using BAO data alone. Based solely on geometric BAO distance ratios, accelerating expansion (w < -1/3) is required with a probability of 99.8 per cent, providing a consistency check of conclusions based on supernovae observations. Further improvements in cosmological constraints will result when the WiggleZ survey data set is complete.

  14. 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.

  15. Cochlear Implant Electrode Effect on Sound Energy Transfer within the Cochlea during Acoustic Stimulation

    PubMed Central

    Greene, Nathaniel T.; Mattingly, Jameson K.; Jenkins, Herman A.; Tollin, Daniel J.; Easter, James R.; Cass, Stephen P.

    2015-01-01

    Hypothesis Cochlear implants (CI) designed for hearing preservation will not alter mechanical properties of the middle and inner ear as measured by intracochlear pressure (PIC) and stapes velocity (Vstap). Background CIs designed to provide combined electrical and acoustic stimulation (EAS) are now available. To maintain functional acoustic hearing, it is important to know if a CI electrode can alter middle or inner ear mechanics, as any alteration could contribute to elevated low-frequency thresholds in EAS patients. Methods Seven human cadaveric temporal bones were prepared, and pure-tone stimuli from 120Hz–10kHz were presented at a range of intensities up to 110 dB SPL. PIC in the scala vestibuli (PSV) and tympani (PST) were measured with fiber-optic pressure sensors concurrently with VStap using laser Doppler vibrometry. Five CI electrodes from two different manufacturers, with varying dimensions were inserted via a round window approach at six different depths (16–25 mm). Results The responses of PIC and VStap to acoustic stimulation were assessed as a function of stimulus frequency, normalized to SPL in the external auditory canal (EAC), in baseline and electrode inserted conditions. Responses measured with electrodes inserted were generally within ~5 dB of baseline, indicating little effect of cochlear implant electrode insertion on PIC and VStap. Overall, mean differences across conditions were small for all responses, and no substantial differences were consistently visible across electrode types. Conclusions Results suggest that the influence of a CI electrode on middle and inner ear mechanics is minimal, despite variation in electrode lengths and configurations. PMID:26333018

  16. 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.

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

    PubMed

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

    2014-07-21

    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.

  18. 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.

  19. 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.

  20. Comparison of an integral equation on energy and the ray-tracing technique in room acoustics.

    PubMed

    Le Bot, A; Bocquillet, A

    2000-10-01

    This paper deals with a comparison of two room acoustic models. The first one is an integral formulation stemming from power balance and the second is the ray-tracing technique with a perfectly diffuse reflection law. The common assumptions to both models are the uncorrelated wave hypothesis and the perfectly diffuse reflection law. The latter allows the use of these methods for nondiffuse fields beyond the validity domain of Sabine's formula. Comparisons of numerical simulations performed with the softwares RAYON and CeReS point out that these results are close to each other and finally, a formal proof is proposed showing that both methods are actually equivalent.

  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. 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

    2013-10-09

    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.

  3. 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.

  4. First-principles investigation of high energy density in PVDF copolymers

    NASA Astrophysics Data System (ADS)

    Ranjan, V.; Lu, Liping; Buongiorno Nardelli, M.; Bernholc, J.

    2008-03-01

    PVDF and its copolymers exhibit excellent electromechanical properties and in the case of PVDF-CTFE also a very high energy density [1]. We have investigated the phase diagram of these systems and can quantitatively explain the observed energy density of PVDF-CTFE as due to a para to ferroelectric phase transition in a disordered, multidomain structure [2]. Our results show that pure PVDF prefers the α phase at zero field. Electric field lowers the free energy of the β phase, resulting in a structural phase transition at a sufficiently high field. Copolymer admixture lowers the critical field and eventually leads to an energetic preference for the β phase even at zero field. For PVDF-CTFE with CTFE content below 17 %, the α phase is still preferred and the field-induced phase transformation reversibly stores large amounts of energy. For PVDF-TeFE, the total energy difference between the two phases is much smaller, resulting in substantially smaller energy density. [1] B. Chu et al., Science 313, 334 (2006). [2] V. Ranjan et al., PRL 99, 047801 (2007).

  5. Finite element modeling of acoustic wave propagation and energy deposition in bone during extracorporeal shock wave treatment

    NASA Astrophysics Data System (ADS)

    Wang, Xiaofeng; Matula, Thomas J.; Ma, Yong; Liu, Zheng; Tu, Juan; Guo, Xiasheng; Zhang, Dong

    2013-06-01

    It is well known that extracorporeal shock wave treatment is capable of providing a non-surgical and relatively pain free alternative treatment modality for patients suffering from musculoskeletal disorders but do not respond well to conservative treatments. The major objective of current work is to investigate how the shock wave (SW) field would change if a bony structure exists in the path of the acoustic wave. Here, a model of finite element method (FEM) was developed based on linear elasticity and acoustic propagation equations to examine SW propagation and deflection near a mimic musculoskeletal bone. High-speed photography experiments were performed to record cavitation bubbles generated in SW field with the presence of mimic bone. By comparing experimental and simulated results, the effectiveness of FEM model could be verified and strain energy distributions in the bone were also predicted according to numerical simulations. The results show that (1) the SW field will be deflected with the presence of bony structure and varying deflection angles can be observed as the bone shifted up in the z-direction relative to SW geometric focus (F2 focus); (2) SW deflection angels predicted by the FEM model agree well with experimental results obtained from high-speed photographs; and (3) temporal evolutions of strain energy distribution in the bone can also be evaluated based on FEM model, with varied vertical distance between F2 focus and intended target point on the bone surface. The present studies indicate that, by combining MRI/CT scans and FEM modeling work, it is possible to better understand SW propagation characteristics and energy deposition in musculoskeletal structure during extracorporeal shock wave treatment, which is important for standardizing the treatment dosage, optimizing treatment protocols, and even providing patient-specific treatment guidance in clinic.

  6. Giant strain-sensitivity of acoustic energy dissipation in solids containing dry and saturated cracks with wavy interfaces.

    PubMed

    Zaitsev, V Yu; Matveev, L A

    2012-01-01

    Mechanisms of acoustic energy dissipation in heterogeneous solids attract much attention in view of their importance for material characterization, nondestructive testing, and geophysics. Due to the progress in measurement techniques in recent years, it has been revealed that rocks can demonstrate extremely high strain sensitivity of seismoacoustic loss. In particular, it has been found that strains of order 10(-8) produced by lunar and solar tides are capable of causing variations in the seismoacoustic decrement on the order of several percent. Some laboratory data (although obtained for higher frequencies) also indicate the presence of very high dissipative nonlinearity. Conventionally discussed dissipation mechanisms (thermoelastic loss in dry solids, Biot and squirt-type loss in fluid-saturated ones) do not suffice to interpret such data. Here the dissipation at individual cracks is revised taking into account the influence of wavy asperities of their surfaces quite typical of real cracks, which can drastically change the values of the relaxation frequencies and can result in giant strain sensitivity of the dissipation without the necessity of assuming the presence of unrealistically thin (and, therefore, unrealistically soft) cracks. In particular, these mechanisms suggest interpretation for observations of pronounced amplitude modulation of seismo-acoustic waves by tidal strains.

  7. Acoustic waves from mechanical impulses due to fluorescence resonant energy (Förster) transfer: Blowing a whistle with light

    NASA Astrophysics Data System (ADS)

    Zurita-Sánchez, J. R.; Henkel, C.

    2012-02-01

    We present a momentum transfer mechanism mediated by electromagnetic fields that originates in a system of two nearby molecules: one excited (donor D*) and the other in ground state (acceptor A). An intermolecular force related to fluorescence resonant energy or Förster transfer (FRET) arises in the unstable D*A molecular system, which differs from the equilibrium van der Waals interaction. Due to the its finite lifetime, a mechanical impulse is imparted to the relative motion in the system. We analyze the FRET impulse when the molecules are embedded in free space and find that its magnitude can be much greater than the single recoil photon momentum, getting comparable with the thermal momentum (Maxwell-Boltzmann distribution) at room temperature. In addition, we propose that this FRET impulse can be exploited in the generation of acoustic waves inside a film containing layers of donor and acceptor molecules, when a picosecond laser pulse excites the donors. This acoustic transient is distinguishable from that produced by thermal stress due to laser absorption, and may therefore play a role in photoacoustic spectroscopy. The effect can be seen as exciting a vibrating system like a string or organ pipe with light; it may be used as an opto-mechanical transducer.

  8. High-energy-density electron beam generation in ultra intense laser-plasma interaction

    NASA Astrophysics Data System (ADS)

    Liu, Jianxun; Ma, Yanyun; Yang, Xiaohu; Zhao, Jun; Yu, Tongpu; Shao, Fuqiu; Zhuo, Hongbin; Gan, Longfei; Zhang, Guobo; Zhao, Yuan; Yang, Jingkang

    2017-01-01

    By using a two-dimensional particle-in-cell simulation, we demonstrate a scheme for high-energy-density electron beam generation by irradiating an ultra intense laser pulse onto an aluminum (Al) target. With the laser having a peak intensity of 4 × 1023 W cm‑2, a high quality electron beam with a maximum density of 117nc and a kinetic energy density up to 8.79 × 1018 J m‑3 is generated. The temperature of the electron beam can be 416 MeV, and the beam divergence is only 7.25°. As the laser peak intensity increases (e.g., 1024 W cm‑2), both the beam energy density (3.56 × 1019 J m‑3) and the temperature (545 MeV) are increased, and the beam collimation is well controlled. The maximum density of the electron beam can even reach 180nc. Such beams should have potential applications in the areas of antiparticle generation, laboratory astrophysics, etc. This work is financially supported by the National Natural Science Foundation of China (Nos. 11475260, 11305264, 11622547, 91230205, and 11474360), the National Basic Research Program of China (No. 2013CBA01504), and the Research Project of NUDT (No. JC14-02-02).

  9. Absorption of surface acoustic waves by graphene

    NASA Astrophysics Data System (ADS)

    Zhang, S. H.; Xu, W.

    2011-06-01

    We present a theoretical study on interactions of electrons in graphene with surface acoustic waves (SAWs). We find that owing to momentum and energy conservation laws, the electronic transition accompanied by the SAW absorption cannot be achieved via inter-band transition channels in graphene. For graphene, strong absorption of SAWs can be observed in a wide frequency range up to terahertz at room temperature. The intensity of SAW absorption by graphene depends strongly on temperature and can be adjusted by changing the carrier density. This study is relevant to the exploration of the acoustic properties of graphene and to the application of graphene as frequency-tunable SAW devices.

  10. Study of Ocean Bottom Interactions with Acoustic Waves by a New Elastic Wave Propagation Algorithm and an Energy Flow Analysis Technique

    DTIC Science & Technology

    2016-06-07

    Study Of Ocean Bottom Interactions With Acoustic Waves By A New Elastic Wave Propagation Algorithm And An Energy Flow Analysis Technique Ru-Shan Wu...imaging to study the wave/sea-bottom interaction, energy partitioning, scattering mechanism and other problems that are crucial for many ocean bottom...Elastic Wave Propagation Algorithm And An Energy Flow Analysis Technique 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR

  11. Energy density of light quark jet using AdS/CFT

    NASA Astrophysics Data System (ADS)

    Morad, R.; Horowitz, W. A.

    2017-01-01

    We study the energy loss rate of light quarks via the AdS/CFT correspondence in both a static and an expanding plasma. Unlike heavy quarks, light quark energy loss in AdS/CFT is surprisingly dependent on both the string initial conditions and the very definition of the jet itself in the gravity theory. We aim to more closely match the string initial conditions to those expected from perturbative quantum chromodyanics (pQCD)-the theory known to describe the physics of high-momentum particles at early times in heavy ion collisions-by computing the energy-momentum tensor associated with the propagation of the classical string solution. The jet energy-momentum tensor in a strongly-coupled calculation can be found by a superposition of contributions from a collection of point particles whose paths approximate the evolution of the string world-sheet. My results show that some times after creation the pair of quark-anti quark, the energy density is not time dependent. This means that the corresponding jet does not lose energy and the associated nuclear modification factor would be one as expected. Also, the results reveal the virtuality dependency of energy density distribution over space. As expected, the energy of a more virtual jet is spread over wider angles.

  12. Advanced High Energy Density Secondary Batteries with Multi-Electron Reaction Materials.

    PubMed

    Chen, Renjie; Luo, Rui; Huang, Yongxin; Wu, Feng; Li, Li

    2016-10-01

    Secondary batteries have become important for smart grid and electric vehicle applications, and massive effort has been dedicated to optimizing the current generation and improving their energy density. Multi-electron chemistry has paved a new path for the breaking of the barriers that exist in traditional battery research and applications, and provided new ideas for developing new battery systems that meet energy density requirements. An in-depth understanding of multi-electron chemistries in terms of the charge transfer mechanisms occuring during their electrochemical processes is necessary and urgent for the modification of secondary battery materials and development of secondary battery systems. In this Review, multi-electron chemistry for high energy density electrode materials and the corresponding secondary battery systems are discussed. Specifically, four battery systems based on multi-electron reactions are classified in this review: lithium- and sodium-ion batteries based on monovalent cations; rechargeable batteries based on the insertion of polyvalent cations beyond those of alkali metals; metal-air batteries, and Li-S batteries. It is noted that challenges still exist in the development of multi-electron chemistries that must be overcome to meet the energy density requirements of different battery systems, and much effort has more effort to be devoted to this.

  13. An interface energy density-based theory considering the coherent interface effect in nanomaterials

    NASA Astrophysics Data System (ADS)

    Yao, Yin; Chen, Shaohua; Fang, Daining

    2017-02-01

    To characterize the coherent interface effect conveniently and feasibly in nanomaterials, a continuum theory is proposed that is based on the concept of the interface free energy density, which is a dominant factor affecting the mechanical properties of the coherent interface in materials of all scales. The effect of the residual strain caused by self-relaxation and the lattice misfit of nanomaterials, as well as that due to the interface deformation induced by an external load on the interface free energy density is considered. In contrast to the existing theories, the stress discontinuity at the interface is characterized by the interface free energy density through an interface-induced traction. As a result, the interface elastic constant introduced in previous theories, which is not easy to determine precisely, is avoided in the present theory. Only the surface energy density of the bulk materials forming the interface, the relaxation parameter induced by surface relaxation, and the mismatch parameter for forming a coherent interface between the two surfaces are involved. All the related parameters are far easier to determine than the interface elastic constants. The effective bulk and shear moduli of a nanoparticle-reinforced nanocomposite are predicted using the proposed theory. Closed-form solutions are achieved, demonstrating the feasibility and convenience of the proposed model for predicting the interface effect in nanomaterials.

  14. 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…

  15. 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.

  16. Laser energy density, structure and properties of pulsed-laser deposited zinc oxide films

    NASA Astrophysics Data System (ADS)

    Tsoutsouva, M. G.; Panagopoulos, C. N.; Kompitsas, M.

    2011-05-01

    Zinc oxide thin films were deposited on soda lime glass substrates by pulsed laser deposition in an oxygen-reactive atmosphere at 20 Pa and a constant substrate temperature at 300 °C. A pulsed KrF excimer laser, operated at 248 nm with pulse duration 10 ns, was used to ablate the ceramic zinc oxide target. The structure, the optical and electrical properties of the as-deposited films were studied in dependence of the laser energy density in the 1.2-2.8 J/cm 2 range, with the aid of X-ray Diffraction, Atomic Force Microscope, Transmission Spectroscopy techniques, and the Van der Pauw method, respectively. The results indicated that the structural and optical properties of the zinc oxide films were improved by increasing the laser energy density of the ablating laser. The surface roughness of the zinc oxide film increased with the decrease of laser energy density and both the optical bang gap and the electrical resistivity of the film were significantly affected by the laser energy density.

  17. 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.

  18. Advanced High Energy Density Secondary Batteries with Multi‐Electron Reaction Materials

    PubMed Central

    Luo, Rui; Huang, Yongxin; Li, Li

    2016-01-01

    Secondary batteries have become important for smart grid and electric vehicle applications, and massive effort has been dedicated to optimizing the current generation and improving their energy density. Multi‐electron chemistry has paved a new path for the breaking of the barriers that exist in traditional battery research and applications, and provided new ideas for developing new battery systems that meet energy density requirements. An in‐depth understanding of multi‐electron chemistries in terms of the charge transfer mechanisms occuring during their electrochemical processes is necessary and urgent for the modification of secondary battery materials and development of secondary battery systems. In this Review, multi‐electron chemistry for high energy density electrode materials and the corresponding secondary battery systems are discussed. Specifically, four battery systems based on multi‐electron reactions are classified in this review: lithium‐ and sodium‐ion batteries based on monovalent cations; rechargeable batteries based on the insertion of polyvalent cations beyond those of alkali metals; metal–air batteries, and Li–S batteries. It is noted that challenges still exist in the development of multi‐electron chemistries that must be overcome to meet the energy density requirements of different battery systems, and much effort has more effort to be devoted to this. PMID:27840796

  19. 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.

  20. Analogy of strain energy density based bone-remodeling algorithm and structural topology optimization.

    PubMed

    Jang, In Gwun; Kim, Il Yong; Kwak, Byung Ban

    2009-01-01

    In bone-remodeling studies, it is believed that the morphology of bone is affected by its internal mechanical loads. From the 1970s, high computing power enabled quantitative studies in the simulation of bone remodeling or bone adaptation. Among them, Huiskes et al. (1987, "Adaptive Bone Remodeling Theory Applied to Prosthetic Design Analysis," J. Biomech. Eng., 20, pp. 1135-1150) proposed a strain energy density based approach to bone remodeling and used the apparent density for the characterization of internal bone morphology. The fundamental idea was that bone density would increase when strain (or strain energy density) is higher than a certain value and bone resorption would occur when the strain (or strain energy density) quantities are lower than the threshold. Several advanced algorithms were developed based on these studies in an attempt to more accurately simulate physiological bone-remodeling processes. As another approach, topology optimization originally devised in structural optimization has been also used in the computational simulation of the bone-remodeling process. The topology optimization method systematically and iteratively distributes material in a design domain, determining an optimal structure that minimizes an objective function. In this paper, we compared two seemingly different approaches in different fields-the strain energy density based bone-remodeling algorithm (biomechanical approach) and the compliance based structural topology optimization method (mechanical approach)-in terms of mathematical formulations, numerical difficulties, and behavior of their numerical solutions. Two numerical case studies were conducted to demonstrate their similarity and difference, and then the solution convergences were discussed quantitatively.