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1

Local Minimum of Elastic Potential Energy on Hemispherical Soft Fingertip  

Microsoft Academic Search

This paper proposes a new contact deformation model between a hemispherical soft fingertip and an object. First, we develop our proposed contact model, in which an elastic potential energy is formulated. Second, we show that the elastic potential energy due to the deformation of the soft fingertip is proportional to the cube of the maximum displacement of that fingertip. Also,

Takahiro Inoue; Shinichi Hirai

2005-01-01

2

A potential for Th from inversion of cohesive energy: Elastic constants  

NASA Astrophysics Data System (ADS)

An interatomic pair potential for Th was derived by using the Chen-Mobius lattice inversion of cohesive energy for fcc Th as a starting point to develop a free-parameter potential suitable to be used in molecular dynamic calculations for predicting microstructure evolution and thermal properties in multicomponent nuclear fuel. The cohesive energy versus lattice parameter of Th was computed from first principles electronic structure calculations. The elastic constants for fcc Th were calculated by applying different types of strain to the starting crystal. Based on this information, the shear modulus, the Youngs modulus and the Poissons ratio were obtained. The computed elastic constants of fcc Th are found to be in a good agreement with experiments and previous theoretical results.

Jaroszewicz, S.; Mosca, H. O.; Garcés, J. E.

2012-08-01

3

Exploiting potential energy storage for cyclic manipulation: An analysis for elastic dribbling with an anthropomorphic robot  

Microsoft Academic Search

For achieving dynamic manipulation capabilities that are comparable to human performance in terms of speed, energetic properties, and robustness, intrinsic elasticity is widely proposed as a necessary robot design element. In this paper we show how passive compliance can be exploited for a 6-degree-of-freedom (DoF) cyclic ball dribbling task with a 7-DoF articulated Cartesian impedance controlled DLR Lightweight Robot III.

Sami Haddadin; Kai Krieger; Mirko Kunze; Alin Albu-Schaffer

2011-01-01

4

Close-coupling calculations of low-energy inelastic and elastic processes in 4He collisions with H2: A comparative study of two potential energy surfaces.  

PubMed

The two most recently published potential energy surfaces (PESs) for the HeH2 complex, the so-called MR (Muchnick and Russek) and BMP (Boothroyd, Martin, and Peterson) surfaces, are quantitatively evaluated and compared through the investigation of atom-diatom collision processes. The BMP surface is expected to be an improvement, approaching chemical accuracy, over all conformations of the PES compared to that of the MR surface. We found significant differences in inelastic rovibrational cross sections computed on the two surfaces for processes dominated by large changes in target rotational angular momentum. In particular, the H2(nu=1,j=0) total quenching cross section computed using the BMP potential was found to be a factor of 1000 larger than that obtained with the MR surface. A lesser discrepancy persists over a large range of energies from the ultracold to thermal and occurs for other low-lying initial rovibrational levels. The MR surface was used in previous calculations of the H2(nu=1,j=0) quenching rate coefficient and gave results in close agreement with the experimental data of Audibert et al. which were obtained for temperatures between 50 and 300 K. Examination of the rovibronic coupling matrix elements, which are obtained following a Legendre expansion of the PES, suggests that the magnitude of the anisotropy of the BMP potential is too large in the interaction region. However, cross sections for elastic and pure rotational processes obtained from the two PESs differ typically by less than a factor of 2. The small differences may be ascribed to the long-range and anharmonic components of the PESs. Exceptions occur for (nu=10,j=0) and (nu=11,j=1) where significant enhancements have been found for the low-energy quenching and elastic cross sections due to zero-energy resonances in the BMP PES which are not present in the MR potential. PMID:15638586

Lee, Teck-Ghee; Rochow, C; Martin, R; Clark, T K; Forrey, R C; Balakrishnan, N; Stancil, P C; Schultz, D R; Dalgarno, A; Ferland, Gary J

2005-01-01

5

Interaction potential for indium phosphide: a molecular dynamics and first-principles study of the elastic constants, generalized stacking fault and surface energies.  

PubMed

Indium phosphide is investigated using molecular dynamics (MD) simulations and density-functional theory calculations. MD simulations use a proposed effective interaction potential for InP fitted to a selected experimental dataset of properties. The potential consists of two- and three-body terms that represent atomic-size effects, charge-charge, charge-dipole and dipole-dipole interactions as well as covalent bond bending and stretching. Predictions are made for the elastic constants as a function of density and temperature, the generalized stacking fault energy and the low-index surface energies. PMID:21817375

Branicio, Paulo Sergio; Rino, José Pedro; Gan, Chee Kwan; Tsuzuki, Hélio

2009-03-01

6

Virtual Laboratory: Potential Energy  

NSDL National Science Digital Library

This web page provides an introduction to mechanical energy, focusing on gravity. It includes a java simulation of a dropped ball showing the conversion of potential energy into kinetic energy. Non-elastic collisions with the ground are included, although there is no discussion of the resultant lost energy. Users can change the mass, initial energy, and percentage of the energy lost during collisions. This item is part of a larger collection of virtual laboratories for physics, astronomy, and environmental science.

Bothun, Gregory

2007-12-03

7

The elastic energy of damaged rocks  

NASA Astrophysics Data System (ADS)

Crustal rocks are typically treated as linear elastic material with constant elastic moduli. This assumption is appropriate for rock with relatively low damage, associated with low concentration of cracks and flaws, and under relatively small strains. However, laboratory and field data indicate that rocks subjected to sufficiently high loads exhibit clear deviations from linear behavior. In general, nonlinear stress-strain relationships of rocks can be approximated by including higher-order terms of the strain tensor in the elastic energy expression (e.g., the Murnaghan model). Such models are successful for calculating rock deformation under high confining pressure. However, values of the third (higher order) Murnaghan moduli estimated from acoustic experiments are one to two orders of magnitude above the expected values of the same moduli estimated from the stress-strain relations in quasi-static rock-mechanics experiments. The Murnaghan model also fails to reproduce an abrupt change in the elastic moduli when deformation changes from compression to tension. Such behavior was observed in laboratory experiments with rocks, concrete, and composite brittle material samples. Bi-linear elastic models with abrupt change of the moduli under stress reversal were suggested based on acoustic experiments ("clapping" nonlinearity) and in continuum damage mechanics (unilateral damage model). Here we present a theoretical basis for general second-order nonlinear expression of the elastic potential. We then show that a simplified version of the general nonlinear model is consistent with bi-linear elastic behavior and accounts for non-linearity even under small strains. We apply the simplified nonlinear model to various laboratory observations, including quasi-static modeling of rocks and composite material with different effective moduli under tension and compression; rock dilation under shear; stress- and damage-induced seismic wave anisotropy observed during cycling load of granite samples; and acoustic experiments analyzing shift of the resonance frequency in rock samples. Comparison between analytical and numerical calculations and experimental results demonstrate that the suggested expression for the elastic potential for rocks accounts for both quasi-static damage accumulation and nonlinear dynamic effects.

Hamiel, Y.; Lyakhovsky, V.; Ben-Zion, Y.

2009-12-01

8

Energy Propagation in a Deformed Elastic Material.  

National Technical Information Service (NTIS)

Resultant material and spatial energy propagation vectors are defined for waves of small amplitude superposed on large static deformations in elastic materials or arbitrary symmetry. It is shown that the resultant material energy propagation vector is in ...

M. A. Hayes R. S. Rivlin

1971-01-01

9

Potential Energy  

NSDL National Science Digital Library

Part of a comprehensive physics tutorial for high school students, this page describes potential energy conceptually and mathematically, provides examples enhanced by illustrations, and problems for practice with drop down boxes for your answers and feedback. In the left navigation bar, click on Kinetic Energy to get parallel information on kinetic energy.

2010-01-01

10

Elastic energy anisotropy effects on antiphase boundaries  

SciTech Connect

The effect of elastic energy on the anisotropy of antiphase boundary (APB) interfacial energy has been studied theoretically. The model used, a generalization of one developed by Kikuchi and Cahn, treats composition and atomic ordering as local variables defined one each of the atomic planes parallel to the APB. The equilibrium APB structure is found as the set of planar variables that minimizes the free energy. A strain energy term involving an orientation-dependent stiffness parameter and a phenomenological law giving lattice constant as a function of local composition and order parameter is included in the definition of the free energy. Elastic effects in APBs in B2 ordered Fe-Al alloys with 0.2--0.3 atomic fraction Al were investigated. It was found that, despite the high elastic anisotropy of Fe-Al alloys, elastic effects would not result in any substantial anisotropy in APB interfacial energy. This is because in Fe-Al alloys the variation in lattice constant due to order parameter variation at the APB is almost completely canceled out by the variation in lattice constant due to compositional variation. In a hypothetical model with physically reasonable parameter, APB energies were found to vary by up to 9% with orientation, purely as a result of elastic effects. It was concluded that elastically induced APB anisotropy would be observable in alloys such as Fe-Si in which lattice constant variations due to order parameter variation are cooperative with those due to compositional variation.

Van Der Heide, R.G.; Allen, S.M. [Massachusetts Inst. of Tech., Cambridge, MA (United States). Dept. of Materials Science and Engineering] [Massachusetts Inst. of Tech., Cambridge, MA (United States). Dept. of Materials Science and Engineering

1996-04-01

11

Mechanics of cuticular elastic energy storage in leg joints lacking extensor muscles in arachnids  

Microsoft Academic Search

Certain leg joints in arachnids lack extensor muscles and have elastically deformable transarticular sclerites spanning their arthrodial membranes, an arrangement consistent with a model in which flexor muscles load transarticular sclerites during flexion and energy from elastic recoil is used for extension. This study quantifies the potential contribution of elastic recoil to extension torque at joints of the fourth leg

Andrew T. Sensenig; Jeffrey W. Shultz

2003-01-01

12

Extended optical model analyses of elastic scattering and fusion cross sections for the {sup 6}Li+{sup 208}Pb system at near-Coulomb-barrier energies using a folding potential  

SciTech Connect

Based on the extended optical model approach in which the polarization potential is decomposed into direct reaction (DR) and fusion parts, simultaneous {chi}{sup 2} analyses are performed for elastic scattering and fusion cross section data for the {sup 6}Li+{sup 208}Pb system at near-Coulomb-barrier energies. A folding potential is used as the bare potential. It is found that the real part of the resultant DR part of the polarization potential is repulsive, which is consistent with the results from the continuum discretized coupled channel (CDCC) calculations and the normalization factors needed for the folding potentials. Further, it is found that both DR and fusion parts of the polarization potential satisfy separately the dispersion relation.

So, W. Y.; Udagawa, T.; Kim, K. S.; Hong, S. W.; Kim, B. T. [Department of Physics, University of Texas, Austin, Texas 78712 (United States); Department of Liberal Arts and Science, Hankuk Aviation University, Koyang 412-791 (Korea, Republic of); Department of Physics and Institute of Basic Science, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of)

2007-02-15

13

Energy of the frequency-elastic effect in solids  

NASA Astrophysics Data System (ADS)

A decrease in the frequency of skeletal vibrations (frequency-elastic effect) has been measured using Raman spectroscopy, and the stretching of backbone interatomic bonds in polyethylene molecules under elastic tensile loading of oriented polyethylene fibers has been measured using X-ray diffraction. It has been found that there are differences in the sign and magnitude of the changes in the zero-point energy and the work of the external force. The energy of the frequency-elastic effect has been explained in terms of the influence exerted by the initial (before loading) anharmonic stretching of backbone bonds and the force of anharmonic pressure, with the separation of the anharmonic (potential) component of the zero-point energy of the solid. A change in the frequency of vibrations corresponds to a change in the harmonic component of the zero-point energy. The loading with an external force causes a redistribution of the zero-point energy components. An energy analysis of the loaded quantum anharmonic oscillator has confirmed the conclusion regarding the mechanism of energy transfer and revealed that, under loading, there is a redistribution of the average values of the kinetic and potential components of the internal energy of the oscillator.

Slutsker, A. I.; Kulik, V. B.

2014-02-01

14

Tidal elastic energy in planetary systems and its dynamic role  

Microsoft Academic Search

An analytical expression for the elastic energy of the planet tidal deformations induced by other bodies in the planetary system and by a central star has been obtained. It was shown that the elastic energy is not additive sum of the elastic energies of separate pairs of bodies but contains additional terms of mutual character. In particular, we have obtained

Yu. V. Barkin; J. M. Ferrandiz

2004-01-01

15

Elastic potentials and the structure of inelastic constitutive laws  

Microsoft Academic Search

Abseact. The existence of a work potential. governing materlal response when elastic behav~or occurs. is shown to prov~de a concise framework for the structure of inelastic constitutive laws. The discussion includes the identification of differential invariants In conjugate stress and straln variables, an examination and reformulat~on of postulates leading to \\

R. HILLt; J. R. Rice

1973-01-01

16

Low Energy Elastic Scattering from Water  

NASA Astrophysics Data System (ADS)

Differential electron scattering cross-sections have been measured for elastic scattering from water molecules. The method of relative flow, but with an aperture replacing traditional gas collimating structures. In addition, the gas source was moved to determine the background scattering contribution The measurements were taken at incident energies of 1eV to 100eV and scattering angles of 5^o to 130^o. Comparisons with theory and former experiments will be presented.

Khakoo, Murtadha A.; Muse, John; Silva, Helen; Lopes, Maria Cristina A.

2008-10-01

17

Second Order Elastic Constants and Some Thermoelastic Properties of Alkali Halides Using WOODCOCK Potential  

NASA Astrophysics Data System (ADS)

Second Order Elastic Constants (S.O.E.C) of NaCl-type crystals have been calculated using the Woodcock potential. Short-range repulsive interactions have been included up to second-nearest neighbors. This potential form represents the composite form of the inverse power dependence and exponential dependence of the repulsive energy on interionic distance. Some thermoelastic and thermodynamic properties such as Anderson-Grüneisen parameters d T, and d S, Volume thermal expansion coefficient b and Grüneisen gama g G have been calculated in terms of calculated values of S.O.E.C and Third Order Elastic Constant ( T.O.E.C).

Yazar, Harun Reþýt; Aðan, Sedat; Çolakoðlu, Kemal

2001-07-01

18

Expression for the granular elastic energy.  

PubMed

Granular solid hydrodynamics (GSH) is a broad-ranged continual mechanical description of granular media capable of accounting for static stress distributions, yield phenomena, propagation and damping of elastic waves, the critical state, shear band, and fast dense flow. An important input of GSH is an expression for the elastic energy needed to deform the grains. The original expression, though useful and simple, has some drawbacks. Therefore a slightly more complicated expression is proposed here that eliminates three of them: (1) The maximal angle at which an inclined layer of grains remains stable is increased from 26^{?} to the more realistic value of 30^{?}. (2) Depending on direction and polarization, transverse elastic waves are known to propagate at slightly different velocities. The old expression neglects these differences, the new one successfully reproduces them. (3) Most importantly, the old expression contains only the Drucker-Prager yield surface. The new one contains in addition those named after Coulomb, Lade-Duncan, and Matsuoka-Nakai-realizing each, and interpolating between them, by shifting a single scalar parameter. PMID:23004747

Jiang, Yimin; Zheng, Hepeng; Peng, Zheng; Fu, Liping; Song, Shixiong; Sun, Qicheng; Mayer, Michael; Liu, Mario

2012-05-01

19

Probing the potential and reaction coupling effects of {sup 6,7}Li+{sup 28}Si at sub- and near-barrier energies with elastic backscattering  

SciTech Connect

The excitation functions for {sup 7}Li+{sup 28}Si quasielastic scattering at 150 deg. and 170 deg. have been measured at sub- and near-barrier energies (0.6 to 1.3 V{sub B}) and the corresponding barrier distributions derived. The results were analyzed within the framework of the optical model using a procedure similar to one used on previous results for {sup 6}Li+{sup 28}Si employing double-folded potentials calculated using the BDM3Y1 effective interaction. The variation of the surface strength of the optical potential as a function of incident energy was compared for the two systems {sup 6}Li+{sup 28}Si and {sup 7}Li+{sup 28}Si, the barrier distributions being used to help better define the potential at the lowest energies. The barrier distributions were also analyzed with continuum-discretized coupled-channel (CDCC) and coupled reaction channel (CRC) calculations as a means of investigating the influence of breakup and transfer reactions on these quantities for these light, weakly bound projectiles.

Zerva, K.; Pakou, A.; Patronis, N.; Aslanoglou, X.; Nicolis, N. G. [Department of Physics and HINP, The University of Ioannina, GR-45110 Ioannina (Greece); Rusek, K. [Heavy Ion Laboratory, University of Warsaw, Warsaw (Poland); Department of Nuclear Reactions, Andrzej Soltan Institute for Nuclear Studies, Warsaw (Poland); Alamanos, N. [CEA-Saclay DSM/IRFU/DIR, F-91191 Gif-sur-Yvette (France); Filipescu, D.; Glodariu, T. [''Horia Hulubei'' National Institute of Physics and Nuclear Engineering (Romania); Keeley, N. [Department of Nuclear Reactions, Andrzej Soltan Institute for Nuclear Studies, Warsaw (Poland); Kokkoris, M. [National Technical University of Athens (Greece); La Commara, M. [Dipartimento di Scienze Fisiche and INFN Sezione di Napoli, I-80125, Napoli (Italy); Lagoyannis, A. [National Research Center Demokritos (Greece); Mazzocco, M. [Dipartimento di Fisica, INFN, I-35131 Padova (Italy); Pierroutsakou, D.; Romoli, M. [INFN Sezione di Napoli, I-80125, Napoli (Italy)

2010-10-15

20

Energy theorems and the J-integral in dipolar gradient elasticity  

Microsoft Academic Search

Within the framework of Mindlin’s dipolar gradient elasticity, general energy theorems are proved in this work. These are the theorem of minimum potential energy, the theorem of minimum complementary potential energy, a variational principle analogous to that of the Hellinger–Reissner principle in classical theory, two theorems analogous to those of Castigliano and Engesser in classical theory, a uniqueness theorem of

H. G. Georgiadis; C. G. Grentzelou

2006-01-01

21

Double folding cluster potential for {sup 12}C+{sup 12}C elastic scattering  

SciTech Connect

Using the alpha ({alpha})-cluster structure of {sup 12}C nucleus, two versions of the {sup 12}C+{sup 12}C real double folded optical potentials have been generated based upon effective {alpha}-{alpha},{alpha}-nucleon (N) and N-N interactions. The obtained potentials, in conjunction with shallow phenomenological Woods-Saxon imaginary parts, successfully reproduce the elastic scattering differential cross section for 12 sets of data over the broad energy range 70-360 MeV. No renormalization of the real folded potentials is required to fit the data. The energy dependence of the extracted real and imaginary volume integrals and total reaction cross section is investigated.

Hassanain, M. A. [Sciences Department, New-Valley Faculty of Education, Assiut University, El-Kharga, New-Valley (Egypt); Ibraheem, Awad A. [Physics Department, Al-Azhar University, Assiut 71524 (Egypt); Farid, M. El-Azab [Physics Department, Assiut University, Assiut 71516 (Egypt)

2008-03-15

22

Elastic Energy Flux by Flexible Polymers in Fluid Turbulence  

NASA Astrophysics Data System (ADS)

We present a study of the energy transfer in the bulk of a turbulent flow with dilute long-chain polymer additives. Based on prior work by Tabor and de Gennes [Europhys. Lett. 2, 519 (1986); Physica (Amsterdam) 140A, 9 (1986)], we propose a theory on the energy flux into the elastic degrees of freedom of the polymer chains. This elastic energy flux, which increases as the length scale decreases, gradually reduces the energy transferred to smaller scales through turbulence cascade and hence suppresses small scale fluctuations. The balance of the elastic energy flux and the turbulence energy cascade gives an elastic length scale, which describes the effect of polymer elasticity on turbulence in the inertial range. Predictions of this new “energy flux balance theory” agree excellently with our experimental results.

Xi, Heng-Dong; Bodenschatz, Eberhard; Xu, Haitao

2013-07-01

23

An effective coulomb potential obtained by using the extended elastic model III for the sub-barrier fusion  

Microsoft Academic Search

Summary  An effective Coulomb potential is defined in the framework of the extended elastic model III for the sub-barrier fusion. By\\u000a using this effective potential the singularity of Rutherford differential cross-section atE=0 disappears. The differential cross-section relative to the new potential attains a maximum value at low energy.

A. Scalia

1991-01-01

24

Potential and kinetic energy  

NSDL National Science Digital Library

What is the difference between potential and kinetic energy? This informational piece, part of a series about the future of energy, introduces students to kinetic and potential energy. The law of conservation of energy is explained, using the example of turning natural gas into electricity. Definitions and examples of potential energy and kinetic energy are provided. Copyright 2005 Eisenhower National Clearinghouse

Project, Iowa P.

2004-01-01

25

Boussinesq–Flamant problem in gradient elasticity with surface energy  

Microsoft Academic Search

The strain gradient elasticity theory with surface energy is applied to Boussinesq–Flamant problem. The solution for the vertical displacements at the surface of half space due to the surface normal line load is presented. The theory includes both volumetric and surface energy terms. Boussinesq–Flamant problem in the strain gradient elasticity is solved by means of Fourier transform. The results obtained

Dai Zhou; Bo Jin

2003-01-01

26

Surface instability in gradient elasticity with surface energy  

Microsoft Academic Search

Biot's theory of plane strain surface instability of an isotropic elastic body under initial stress in finite strain is extended to include higher order strain-gradients. Higher order straingradients are properly introduced in the definition of the strain energy density, leading to an anisotropic gradient elasticity theory with surface energy. Accordingly, the present theory includes two material lengths characterizing the volume

I. Vardoulakis

1998-01-01

27

Finite-Difference Time-Domain Numerical Analysis of Elastic Wave Fields Using both Elastic and Velocity Potential Variables  

NASA Astrophysics Data System (ADS)

The use of both elastic variables and velocity potentials is proposed for the analysis of elastic wave fields in isotropic solids by finite-difference time-domain (FDTD) methods. The term ‘elastic variables’ refers to stresses and particle velocities. Velocity potentials can be directly derived using the same leap-frog finite-difference scheme as in the FDTD method. In some situations, for example, where an absorbing boundary is present, it is more straightforward to calculate using velocity potentials. This approach also provides an easy way to handle of complex elastic wave phenomena. On the other hand, many other types of boundary conditions are often expressed in terms of elastic variables. In these situations, it is more convenient to use elastic variables for calculation. Some examples are introduced here to illustrate the efficiency of the proposed technique. First, the method was used for the case of an absorbing boundary. In the model, almost all analysis was carried out using values of stress and particle velocity, but velocity potentials were applied near the absorbing boundary on the truncated interface. Second, an interface between elastic variables and velocity potentials, namely a stress-velocity/potentials interface, was constructed around a scattering object. External to the interface, stresses and particle velocities were used for calculation, and potential variables were applied inside the interface. In a third example, calculations were made over almost the entire analytical region using potential values, but in the neighborhood of the free boundary, elastic variables were used. All the examples above were analyzed numerically using the FDTD method, and the results confirmed the usefulness of the method.

Sato, Masahiro

2006-05-01

28

Measurement and folding-potential analysis of the elastic ?-scattering on light nuclei  

NASA Astrophysics Data System (ADS)

Differential cross sections of ?-elastic scattering have been measured for the target nuclei11B,12C,13C,14N,15N, and16O at E=48.7 and 54.1 MeV and for the nuclei17O,18O, and20Ne at E=54.1 MeV. The experimental results were analysed in terms of the optical model using different complex potentials. Special emphasis is given to the application of the double-folding approach for the real part of the potential. The imaginary part is expressed in terms of Fourier-Bessel functions. Differential cross sections for the ?-16O scattering over a wide energy range and for the elastic ?-scattering for nuclei in the mass range A=11 up to A=24 at E=54.1 MeV are analysed by this method. A close correlation between the absorptive part of the potential and nuclear deformation is observed.

Abele, H.; Hauser, H. J.; Körber, A.; Leitner, W.; Neu, R.; Plappert, H.; Rohwer, T.; Staudt, G.; Straßer, M.; Weite, S.; Walz, M.; Eversheim, P. D.; Hinterberger, F.

1987-12-01

29

Calculation of the Helmholtz potential of an elastic strand in an external electric field.  

PubMed

We derive from statistical mechanics the Gibbs free energy of an elastic random-walk chain affected by the presence of an external electric field. Intrachain charge interactions are ignored. In addition, we find two approximations of the Helmholtz potential for this system analogous to the gaussian and Cohen-Pade? approximations for an elastic strand without the presence of an electric field. Our expressions agree well with exact numerical calculations of the potential in a wide range of conditions. Our analog of the gaussian approximation exhibits distortion of the monomer density due to the presence of the electric field, and our analog of the Cohen-Pade? approximation additionally includes finite chain extensibility effects. The Helmholtz potential may be used in modeling the dynamics of electrophoresis experiments. PMID:21322738

Khaliullin, Renat N; Schieber, Jay D

2011-02-14

30

Non-monotonic potential description of alpha-Zr refractive elastic scattering  

NASA Astrophysics Data System (ADS)

Experimental differential cross sections of ? elastic scattering by 90Zr in the 15.0-141.7 MeV range of the bombarding energies have been analysed within the framework of an optical model using non-monotonic (NM) potentials. These potentials are generated from the energy-density functional theory using a realistic two-nucleon potential coupled with an appropriate consideration of the Pauli principle. The NM nature of the real part of the potential seems to be gradually diminishing at energies beyond 118.0 MeV. The Airy structure of the nuclear rainbow scattering data in the energy range of 79.5-141.7 MeV is for the first time well accounted for by the shallow NM potential. Two potential families, which are located in the real part, bear a linear variation of a volume integral in the energy range 25.0-141.7 MeV with a threshold anomaly at the lower energies. The potential contains an interior repulsive part that, with energy, shifts towards the surface and gradually weakens until it is almost lost in the nuclear surface. The requirement of a deep attractive real part of the nuclear potential seems to be generally non-stringent for describing the nuclear rainbow oscillations. Some discrete ambiguities in the potentials seem to persist even when the ‘exponential falloff’ in the angular distribution following the ‘rainbow angle’ is well reproduced in this investigation using the NM real part of the optical potentials.

Hossain, S.; Billah, Masum; Azad, M. M. B.; Parvin, Farzana; Abdullah, M. N. A.; Hasan, K. M.; Uddin, M. A.; Tariq, A. S. B.; Basak, A. K.; Reichstein, I.; Malik, F. B.

2013-10-01

31

Microscopic optical potential for -nucleus elastic scattering in a Dirac-Brueckner-Hartree-Fock approach  

Microsoft Academic Search

The microscopic optical model potential (OMP) of -nucleus elastic scattering based on a double-folding model (DFM) is studied. The nucleon OMPs in nuclear matter as well as the nucleon-nucleon (NN) effective interaction are calculated in the framework of the Dirac-Brueckner-Hartree-Fock (DBHF) approach, in which the density and energy dependence is parametrized by polynomial expansions. The microscopic OMP of nucleus-nucleus scattering

Zou Wei; Tian Yuan; Ma Zhongyu

2008-01-01

32

Estimating disaggregated price elasticities in industrial energy demand  

SciTech Connect

Econometric energy models are used to evaluate past policy experiences, assess the impact of future policies and forecast energy demand. This paper estimates an industrial energy demand model for the province of Ontario using a linear-logit specification for fuel type equations which are embedded in an aggregate energy demand equation. Short-term, long-term, own- and cross-price elasticities are estimated for electricity, natural gas, oil and coal. Own- and cross-price elasticities are disaggregated to show that overall price elasticities and the energy-constant price elasticities when aggregate energy use is held unchanged. These disaggregations suggest that a substantial part of energy conservation comes from the higher aggregate price of energy and not from interfuel substitution. 13 refs., 2 tabs.

Elkhafif, M.A.T. (Ontario Ministry of Energy, Toronto (Canada))

1992-01-01

33

Fusion and Quasi-elastic scattering around the Coulomb barrier: determination of inter-nucleus potential  

NASA Astrophysics Data System (ADS)

We invert experimental data for heavy-ion fusion cross sections at energies well below the Coulomb barrier in order to directly determine the internucleus potential between the colliding nuclei. In contrast to the previous applications of the inversion formula, we explicitly take into account the effect of channel couplings on fusion reactions, by assuming that fusion cross sections at deep subbarrier energies are governed by the lowest barrier in the barrier distribution. The surface region of the internuclear potential is determined from quasi-elastic scattering at deep subbarrier energies, while the inner part is determined with the WKB formula. We apply this procedure to the 16O+144Sm and 16O+208Pb reactions, and find that the inverted internucleus potential are much thicker than phenomenological potentials.

Hagino, K.

2009-05-01

34

Energy in elastic fiber embedded in elastic matrix containing incident SH wave  

NASA Technical Reports Server (NTRS)

A single elastic fiber embedded in an infinite elastic matrix is considered. An incident plane SH wave is assumed in the infinite matrix, and an expression is derived for the total energy in the fiber due to the incident SH wave. A nondimensional form of the fiber energy is plotted as a function of the nondimensional wavenumber of the SH wave. It is shown that the fiber energy attains maximum values at specific values of the wavenumber of the incident wave. The results obtained here are interpreted in the context of phenomena observed in acousto-ultrasonic experiments on fiber reinforced composite materials.

Williams, James H., Jr.; Nagem, Raymond J.

1989-01-01

35

Dynamic polarization potential effects on vector analyzing powers of 6Li- 28Si elastic scattering from non-monotonic potentials  

NASA Astrophysics Data System (ADS)

Experimental cross section ( CS) and vector analyzing power ( VAP) data of the 6Li- 28Si elastic scattering at 22.8 MeV are analyzed in the coupled-channels (CC) and coupled discretized continuum channels (CDCC) methods. Non-monotonic (NM) 6Li and ? potentials of microscopic origin are employed, respectively, in the CC calculations and to generate folding potentials for the CDCC calculations. The study demonstrates that the use of central NM potentials can generate an appropriate dynamic polarization potential (DPP) required to describe both the CS and VAP data without the necessity of renormalization. This also produces an effective spin-orbit (SO) potential to account for the iT data without the requirement of an additional static SO potential at the incident energy considered.

Basak, A. K.; Roy, P. K.; Hossain, S.; Abdullah, M. N. A.; Tariq, A. S. B.; Uddin, M. A.; Reichstein, I.; Malik, F. B.

2010-08-01

36

Calculations of {sup 8}He+p elastic cross sections using a microscopic optical potential  

SciTech Connect

An approach to calculate microscopic optical potential with the real part obtained by a folding procedure and with the imaginary part inherent in the high-energy approximation is applied to study the {sup 8}He+p elastic-scattering data at energies of tens of MeV/nucleon. The neutron and proton density distributions obtained in different models for {sup 8}He are used in the calculations of the differential cross sections. The role of the spin-orbit potential is studied. Comparison of the calculations with the available experimental data on the elastic-scattering differential cross sections at beam energies of 15.7, 26.25, 32, 66, and 73 MeV/nucleon is performed. The problem of the ambiguities of the depths of each component of the optical potential is considered by means of the imposed physical criterion related to the known behavior of the volume integrals as functions of the incident energy. It is shown also that the role of the surface absorption is rather important, in particular for the lowest incident energies (e.g., 15.7 and 26.25 MeV/nucleon)

Lukyanov, V. K.; Zemlyanaya, E. V.; Lukyanov, K. V. [Joint Institute for Nuclear Research, Dubna RU-141980 (Russian Federation); Kadrev, D. N.; Antonov, A. N.; Gaidarov, M. K. [Institute for Nuclear Research and Nuclear Energy, Bulgarian Academy of Sciences, Sofia 1784 (Bulgaria); Massen, S. E. [Department of Theoretical Physics, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece)

2009-08-15

37

A Microscopic Optical Potential Approach to {sup 6,8}He+p Elastic Scattering  

SciTech Connect

A microscopic approach to calculate the optical potential (OP) with the real part obtained by a folding procedure and with the imaginary part inherent in the high-energy approximation (HEA) is applied to study the {sup 6,8}He+p elastic scattering data at energies of tens of MeV/N. The OP's and the cross sections are calculated using different models for the neutron and proton densities of {sup 6,8}He. The role of the spin-orbit (SO) potential and effects of the energy and density dependence of the effective NN forces are studied. Comparison of the calculations with the available experimental data on the elastic scattering differential cross sections at beam energies <100 MeV/N is performed and conclusions on the role of the aforesaid effects are made. It is shown that the present approach, which uses only parameters that renormalize the depths of the OP, can be applied along with other methods like that from the microscopic g-matrix description of the complex proton optical potential.

Lukyanov, V. K.; Zemlyanaya, E. V.; Lukyanov, K. V. [Joint Institute for Nuclear Research, Dubna 141980 (Russian Federation); Kadrev, D. N.; Antonov, A. N.; Gaidarov, M. K. [Institute for Nuclear Research and Nuclear Energy, Bulgarian Academy of Sciences, Sofia 1784 (Bulgaria); Massen, S. E. [Department of Theoretical Physics, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece)

2009-08-26

38

Insights into low-energy elastic scattering of halo nuclei  

NASA Astrophysics Data System (ADS)

Recent measurements of low-energy (quasi)elastic-scattering angular distribution of halo nuclei have shown a strong suppression of the Coulomb-nuclear interference peak. Examining the components of the elastic-scattering differential cross sections for 11Be + 64Zn and 6He + 208Pb at energies near the Coulomb barrier, this appears to be caused by a dramatic phase-change (destructive) of the reduced Coulomb-nuclear interference term due to continuum couplings.

Diaz-Torres, Alexis; Moro, Antonio M.

2014-06-01

39

Energy shaping control for robot manipulators in explicit force regulation tasks with elastic environments  

Microsoft Academic Search

In this paper, we analyse and present a control approach using the energy shaping formulation to explicitly regulate the applied force of a robot manipulator in contact with a purely elastic environment. The potential energy of the robot-environment system is shaped in a way that its local equilibrium implies the application of the desired force onto the contact surface. This

David Navarro-Alarcon; Peng Li; Hiu Man Yip

2011-01-01

40

Measuring liquid crystal elastic constants with free energy perturbations.  

PubMed

A first principles method is proposed to calculate the Frank elastic constants of nematic liquid crystals. These include the constants corresponding to standard splay, twist and bend deformations, and an often-ignored surface-like contribution known as saddle-splay. The proposed approach is implemented on the widely studied Gay-Berne (3, 5, 2, 1) model [J. G. Gay and B. J. Berne, J. Chem. Phys., 1981, 74, 3316], and the effects of temperature and system size on the elastic constants are examined in the nematic phase. The results of simulations for splay, twist, and bend elastic constants are consistent with those from previous literature reports. The method is subsequently applied to the saddle-splay elastic constant k24 which is found to exist at the limits of the Ericksen inequalities governing positive definite free energy. Finally, extensions of the method are discussed that present a new paradigm for in silico measurements of elastic constants. PMID:24837037

Joshi, Abhijeet A; Whitmer, Jonathan K; Guzmán, Orlando; Abbott, Nicholas L; de Pablo, Juan J

2014-02-14

41

Elastic Hadron Scattering on Li Isotopes at Intermediate Energies  

SciTech Connect

The elastic scattering of hadrons (protons, charged pions, and positively charged kaons) on {sup 6,7,8}Li nuclei is analyzed on the basis of Glauber-Sitenko diffraction theory. A few nuclear-wave-function versions found within two- and three-particle potential cluster models are used in the calculations. It is shown that the application of these wave functions in diffraction theory makes it possible to describe adequately the experimental differential cross sections and analyzing powers in hadron scattering at intermediate energies. In this study, particular attention is given to a comparison of the scattering of different particles on the same target nucleus, as well as to a comparison of scattering of particles of the same sort on different target nuclei.

Zhusupov, M.A.; Imambekov, O. [Institute of Experimental and Theoretical Physics, Kazakh State University, ul. Timiryazeva 46, Almaty, 480121 (Kazakhstan); Ibraeva, E.T. [Institute of Nuclear Physics, National Nuclear Center of the Republic of Kazakhstan, Almaty, 480082 (Kazakhstan)

2005-01-01

42

Quasi-elastic nucleon-nucleus scattering at high energy  

Microsoft Academic Search

Summary  The angular distribution for elastic nucleon-nucleon scattering at high energy is sharply peaked in the forward direction.\\u000a As a consequence, there is an angular interval in nucleon-nucleus scattering to which successive small-angle elastic nucleon-bound\\u000a nucleon scatterings are more likely to contribute than a single nucleon-bound nucleon scattering through the angle of observation.\\u000a Such « plural » collisions result in outgoing

R. Karplus; Y. Yamaguchi

1961-01-01

43

The elastic energy of sharply bent nicked DNA  

NASA Astrophysics Data System (ADS)

We obtain measurements of the elastic energy of short (18-30 bp) molecules of ds DNA constrained into a sharply bent conformation, using a thermodynamic method with the DNA in solution. We consider the case where there is one nick in the ds DNA, and find that the system develops a kink at a critical torque ?c?27 pN×nm. In this regime the elastic energy is linear in the end-to-end distance (EED). For smaller torques the DNA is smoothly bent and described by the worm-like-chain energy, which is also approximately linear in the EED, but with a different slope. Thus we access both the high and low elastic energy regimes, and the transition between the two.

Qu, Hao; Tseng, Chiao-Yu; Wang, Yong; Levine, Alex J.; Zocchi, Giovanni

2010-04-01

44

Cracks in gradient elastic bodies with surface energy  

Microsoft Academic Search

In the present paper the effect of higher order gradients on the structure of line-crack tips is determined. In particular we introduce in the constitutive equations of the linear deformation of an elastic solid a volumetric energy term, which includes the contribution of the strain gradient, and a surface energy gradient dependent term and then determine the effect of these

G. Exadaktylos; I. Vardoulakis; E. Aifantis

1996-01-01

45

Quasi-elastic nuclear scattering at high energies  

NASA Technical Reports Server (NTRS)

The quasi-elastic scattering of two nuclei is considered in the high-energy optical model. Energy loss and momentum transfer spectra for projectile ions are evaluated in terms of an inelastic multiple-scattering series corresponding to multiple knockout of target nucleons. The leading-order correction to the coherent projectile approximation is evaluated. Calculations are compared with experiments.

Cucinotta, Francis A.; Townsend, Lawrence W.; Wilson, John W.

1992-01-01

46

Elasticity  

NASA Astrophysics Data System (ADS)

The subject of Elasticity is concerned with the determination of the stresses and displacements in a body as a result of applied mechanical or thermal loads, for those cases in which the body reverts to its original state on the removal of the loads. In this book, we shall further restrict attention to the case of linear infinitesimal elasticity, in which the stresses and displacements are linearly proportional to the applied loads and the displacements are small in comparison with the characteristic length dimensions of the body. These restrictions ensure that linear superposition can be used and enable us to employ a wide range of series and transform techniques which are not available for non-linear problems.

Barber, J. R.

47

Curve Crossing for Low Energy Elastic Scattering of He (Plus) by Ne.  

National Technical Information Service (NTIS)

The perturbation seen in the experimental differential elastic scattering cross section for the 40 eV He(+) + Ne system was attributed to a single crossing of two intermolecular potential energy curves. A new theoretical treatment of the curve crossing pr...

L. D. Doverspike R. L. Champion S. M. Bobbio

1972-01-01

48

Insensitivity to the long-range Coulomb potential in laser-induced elastic scattering of electrons with ions  

NASA Astrophysics Data System (ADS)

Recently, laser-induced electron diffraction has been used to image molecular structures with subangstrom precision and exposure times of a few femtoseconds by Blaga et al. [Nature (London) 483, 194 (2012), 10.1038/nature10820], who treated molecular ions as neutral molecules in the calculation of differential cross section (DCS) for elastic scattering of electrons by molecular ions. In this work, we investigate the long-range and short-range potential effects in elastic scattering of electrons with ions and atoms. It has been found that for incident electron energies above 100 eV and scattering angles greater than 40?, the DCSs of long-range Coulomb potential scattering can be neglected and the DCSs for elastic scattering of electrons with atomic ions and neutral atoms agree well. Therefore, the validity of the treatment in Blaga et al. is verified.

Chen, Zhangjin; Xu, Junliang; Yang, Weifeng; Song, Xiaohong

2013-12-01

49

Intermediate energy proton-deuteron elastic scattering  

NASA Technical Reports Server (NTRS)

A fully symmetrized multiple scattering series is considered for the description of proton-deuteron elastic scattering. An off-shell continuation of the experimentally known twobody amplitudes that retains the exchange symmeteries required for the calculation is presented. The one boson exchange terms of the two body amplitudes are evaluated exactly in this off-shell prescription. The first two terms of the multiple scattering series are calculated explicitly whereas multiple scattering effects are obtained as minimum variance estimates from the 146-MeV data of Postma and Wilson. The multiple scattering corrections indeed consist of low order partial waves as suggested by Sloan based on model studies with separable interactions. The Hamada-Johnston wave function is shown consistent with the data for internucleon distances greater than about 0.84 fm.

Wilson, J. W.

1973-01-01

50

Using hard dihadron correlations to constrain elastic energy loss  

NASA Astrophysics Data System (ADS)

One contribution to the energy loss of hard partons propagating through a medium as created in ultrarelativistic heavy-ion (A-A) collisions are elastic scattering processes with medium constituents. The magnitude of this energy loss contribution depends crucially on the effective mass of the medium constituents—in the limit of nonrecoiling static scattering centers, elastic energy loss vanishes. Thus, it is important to constrain the amount of elastic energy loss in order to gain information about the nature of the degrees of freedom in the medium as resolved by a hard parton. So far, the relative fraction of elastic (or rather incoherent) energy loss has been constrained from above by using path-length dependent observables. However, using the observation that subleading gluon energy dissipation into the medium is probed by some observables, such as hard dihadron correlations or the dijet asymmetry, a constraint from below can also be found. In this work, this idea is worked out within the in-medium shower evolution Monte Carlo (MC) code YaJEM-D.

Renk, Thorsten

2011-12-01

51

Misfit elastic energy and a continuum model for epitaxial growth with elasticity on vicinal surfaces  

NASA Astrophysics Data System (ADS)

In heteroepitaxial growth, the mismatch between the lattice constants in the film and the substrate causes misfit strain in the film, making a flat surface unstable to small perturbations. This morphological instability is called Asaro-Tiller-Grinfeld (ATG) instability. In practice, most devices are fabricated on vicinal surfaces which consist of steps and terraces. In this case, the misfit strain causes step bunching and traditional continuum models for the ATG instability do not apply directly. In this paper, we present a continuum model for this elastically driving step bunching. We validate our model by performing linear stability analysis and numerical simulation in the nonlinear regime. We also present a continuum description for the misfit elastic energy on vicinal surface which incorporates the underlying atomic features of the vicinal surface.

Xiang, Yang; E, Weinan

2004-01-01

52

Elastic gamma -Proton Scattering at Low and Intermediate Energies.  

National Technical Information Service (NTIS)

A new dispersive analysis of the elastic gamma -proton scattering at photon laboratory energies lower than 450 MeV, based on the use of Bardeen-Tung invariant amplitudes free of both kinematical singularities and zeros, is presented. The requirements of r...

I. Guiasu C. Pomponiu E. E. Radescu

1977-01-01

53

ElasticTree: Saving Energy in Data Center Networks  

Microsoft Academic Search

Networks are a shared resource connecting critical IT in- frastructure, and the general practice is to always leave them on. Yet, meaningful energy savings can result from improving a network's ability to scale up and down, as traffic demands ebb and flow. We present ElasticTree, a network-wide power1 manager, which dynamically ad- justs the set of active network elements —

Brandon Heller; Srinivasan Seetharaman; Priya Mahadevan; Yiannis Yiakoumis; Puneet Sharma; Sujata Banerjee; Nick McKeown

2010-01-01

54

Measurements of radiated elastic wave energy from dynamic tensile cracks  

NASA Technical Reports Server (NTRS)

The role of fracture-velocity, microstructure, and fracture-energy barriers in elastic wave radiation during a dynamic fracture was investigated in experiments in which dynamic tensile cracks of two fracture cofigurations of double cantilever beam geometry were propagating in glass samples. The first, referred to as primary fracture, consisted of fractures of intact glass specimens; the second configuration, referred to as secondary fracture, consisted of a refracture of primary fracture specimens which were rebonded with an intermittent pattern of adhesive to produce variations in fracture surface energy along the crack path. For primary fracture cases, measurable elastic waves were generated in 31 percent of the 16 fracture events observed; the condition for radiation of measurable waves appears to be a local abrupt change in the fracture path direction, such as occurs when the fracture intersects a surface flaw. For secondary fractures, 100 percent of events showed measurable elastic waves; in these fractures, the ratio of radiated elastic wave energy in the measured component to fracture surface energy was 10 times greater than for primary fracture.

Boler, Frances M.

1990-01-01

55

High Energy Elastic Hadron Scattering. Experiment, Data and Theoretical Descriptions.  

National Technical Information Service (NTIS)

The paper deals with the WA7 experiment at the CERN super proton synchrotron (SPS). The elastic differential cross sections of pion-proton, kaon-proton, antiproton-proton, and proton-proton at lower SPS energies over a wide range of momentum transfer were...

T. A. Fearnly

1986-01-01

56

Elastic np ? np( pn) scattering at intermediate energies  

NASA Astrophysics Data System (ADS)

The study of the elastic np ? np( pn) scattering was carried out at the momenta of incident quasimonochromatic neutrons P 0 = 1.43, 2.23 and 5.20 GeV/ c. The differential cross sections of the processes of elastic np scattering, both without (cos ?* p < 0) and with charge exchange (cos ?* p >0) of nucleons, are analyzed. The results are compared with the data of other experiments. The suggested pole model takes into account exchange by ? meson, ? meson, and includes the peripheral exchange mechanism. This model permits one to get a good description of the data of elastic np scattering at the energy region 1-10 GeV.

Troyan, Yu. A.; Anikina, M. Kh.; Belyaev, A. V.; Ierusalimov, A. P.; Troyan, A. Yu.

2014-03-01

57

Elastic positron-cadmium scattering at low energies  

SciTech Connect

The elastic and annihilation cross sections for positron-cadmium scattering are reported up to the positronium-formation threshold (at 2.2 eV). The low-energy phase shifts for the elastic scattering of positrons from cadmium were derived from the bound and pseudostate energies of a very large basis configuration-interaction calculation of the e{sup +}-Cd system. The s-wave binding energy is estimated to be 126{+-}42 meV, with a scattering length of A{sub scat}=(14.2{+-}2.1)a{sub 0}, while the threshold annihilation parameter, Z{sub eff}, was 93.9{+-}26.5. The p-wave phase shift exhibits a weak shape resonance that results in a peak Z{sub eff} of 91{+-}17 at a collision energy of about 490{+-}50 meV.

Bromley, M. W. J.; Mitroy, J. [Department of Physics and Computational Science Research Center, San Diego State University, San Diego, California 92182 (United States); ARC Centre for Antimatter-Matter Studies and School of Engineering, Charles Darwin University, Darwin, Northern Territory 0909 (Australia)

2010-05-15

58

Complementary energy release rates and dual conservation integrals in micropolar elasticity  

Microsoft Academic Search

The complementary energy momentum tensor, expressed in terms of the spatial gradients of stress and couple-stress, is used to construct the J^k and L^k conservation integrals of infinitesimal micropolar elasticity. The derived integrals are related to the release rates of the complementary potential energy associated with a defect translation or rotation. A nonconserved M^ integral is also derived and related

V. A. Lubarda; X. Markenscoff

2007-01-01

59

Elastic diffractive scattering of nucleons at ultra-high energies  

NASA Astrophysics Data System (ADS)

A simple Regge-eikonal model with the eikonal represented as a single-reggeon-exchange term is applied to description of the nucleon-nucleon elastic diffractive scattering at ultra-high energies. The range of validity of the proposed approximation is discussed. The model predictions for the proton-proton cross-sections at the collision energy 14 TeV are given.

Godizov, A. A.

2014-07-01

60

Probing internucleus potential with large-angle quasi-elastic scattering  

NASA Astrophysics Data System (ADS)

Recent measurements for fusion cross section at energies around the Coulomb barrier have systematically indicated a significant deviation of fusion cross sections from a prediction of double-folding model. It has been argued that the deviation can be accounted for if one uses a large value of surface diffuseness parameter for a Woods-Saxon internuclear potential. We investigate this problem using large-angle quasi-elastic scattering, that is a good counterpart of fusion reaction. Towards a reconciliation of the apparent anomaly in the diffuseness parameter for fusion reactions, we also discuss possible ingredients which are missing in present nuclear reaction models. Those include a deviation from the frozen density approximation, the effect of antisymmetrization and the role of coordinate dependent moment of inertia for the relative motion between the colliding nuclei.

Hagino, K.; Washiyama, K.

2006-08-01

61

Microscopic optical potential for alpha-nucleus elastic scattering in a Dirac-Brueckner-Hartree-Fock approach  

Microsoft Academic Search

The microscopic optical model potential (OMP) of alpha-nucleus elastic scattering based on a double-folding model (DFM) is studied. The nucleon OMPs in nuclear matter as well as the nucleon-nucleon (NN) effective interaction are calculated in the framework of the Dirac-Brueckner-Hartree-Fock (DBHF) approach, in which the density and energy dependence is parametrized by polynomial expansions. The microscopic OMP of nucleus-nucleus scattering

Wei Zou; Yuan Tian; Zhong-Yu Ma

2008-01-01

62

Antiproton-induced elastic and inelastic scattering at intermediate energies  

SciTech Connect

With the construction and subsequent operation of LEAR, beams of low-energy antiproton with previously unobtainable intensity and quality were possible. Elastic and inelastic scattering experiments were performed on several nuclei in both the p- and sd-shell as well as targets of heavier mass. In the very near future experiments with antiproton having momentum of up to 2 Gev/c will be possible. It is the purpose of this brief article to report results of initial calculations of {anti p}-nucleus scattering for energies that span this new energy region and for which the elementary {anti p}N amplitudes are known. 4 figs.

Ma, W.H.; Strottman, D.D.

1991-01-01

63

Gradient elasticity with surface energy: Mode-I crack problem  

Microsoft Academic Search

The solution of the mode-I crack problem is given by using an anisotropic strain-gradient elasticity theory with surface energy, extending previous results by Vardoulakis and co-workers, as well as by Aifantis and co-workers. The solution of the problem is derived by applying the Fourier transform technique and the theory of dual integral and Fredholm integral equations. Asymptotic analysis of the

G. Exadaktylos

1998-01-01

64

Gradient elasticity with surface energy: mode-III crack problem  

Microsoft Academic Search

In this paper an anisotropic strain-gradient dependent theory of elasticity is exploited, which contains both volumetric and surface energy gradient dependent terms. The theory is applied to the solution of the mode-III crack problem and is extending previous results by Aifantis and co-workers. The two boundary value problems corresponding to the “unclamped” and “clamped” crack tips, respectively, are solved analytically.

E. Aifantis

1996-01-01

65

Strain energy-based homogenization of nonlinear elastic particulate composites  

Microsoft Academic Search

The macroscopic constitutive law for a heterogeneous solid containing two dissimilar nonlinear elastic phases undergoing finite deformation is obtained. Attention is restricted to the case of spherical symmetry such that only the materials consisting of an irregular suspension of perfectly spherical particles experiencing all-round uniform loading are considered which leads to a one-dimensional modeling. For the homogenization procedure, a strain–energy

R. Avazmohammadi; R. Naghdabadi

2009-01-01

66

Low-energy antiproton-nucleus elastic scattering  

SciTech Connect

We have studied antiproton elastic scattering on Al, Cu, and Pb for two incident momenta: 514 and 633 MeV/c. The angular region covered extends from the forward Coulomb region to approximately 30 deg. The differential cross sections were analyzed using a nonrelativistic optical potential of the Woods-Saxon form, with the imaginary shape taken from electron scattering data. We obtained fits for the strengths of the real and imaginary parts of the potential, (V/sub o/,W/sub o/), of (51, 116) MeV for Al, (12, 71) MeV for Cu, and (12, 278) MeV for Pb.

Ashford, V.; Sainio, M.E.; Sakitt, M.; Skelly, J.; Debbe, R.; Fickinger, W.; Marino, R.; Robinson, D.K.

1984-09-01

67

Elastic and inelastic scattering of alpha particles from 40,44Ca over a broad range of energies and angles  

Microsoft Academic Search

Angular distributions for alpha particle elastic scattering by 40,44Ca and excitation of the 3.73 MeV 3- collective state of 40Ca were measured for incident energies ranging from 40 to 62 MeV. An extensive optical model analysis of these elastic scattering cross sections and other available data, using squared Woods-Saxon form factors, results in potentials with fixed geometry for both real

Th. Delbar; Gh. Grégoire; G. Paic; R. Ceuleneer; F. Michel; R. Vanderpoorten; A. Budzanowski; H. Dabrowski; L. Freindl; K. Grotowski; S. Micek; R. Planeta; A. Strzalkowski; K. A. Eberhard

1978-01-01

68

Elastic backscattering measurements for {sup 6}Li+{sup 28}Si at sub- and near-barrier energies  

SciTech Connect

Elastic backscattering measurements were performed for the weakly bound nucleus {sup 6}Li on a {sup 28}Si target at sub- and near-barrier energies (0.6 to 1.3 V{sub C.B.}). Excitation functions of elastic scattering cross sections were measured at 150 deg. and 170 deg. and the corresponding ratios to Rutherford scattering and relevant barrier distributions were formed. The results are discussed in terms of the potential threshold anomaly and the reaction mechanisms involved.

Zerva, K.; Patronis, N.; Pakou, A.; Aslanoglou, X.; Nicolis, N. G. [Department of Physics, University of Ioannina, GR-45110 Ioannina (Greece); Alamanos, N. [DSM/DAPNIA CEA SACLAY, F-91191 Gif-sur-Yvette (France); Filipescu, D.; Glodariu, T. ['Horia Hulubei' National Institute of Physics and Nuclear Engineering, Bucharest-Magurele (Romania); Kokkoris, M. [National Technical University of Athens, Athens (Greece); La Commara, M. [Dipartimento di Scienze Fisiche and INFN Sezione di Napoli, I-80125, Napoli (Italy); Lagoyannis, A. [National Research Center Demokritos, Agia Paraskevi (Greece); Mazzocco, M. [Dipartimento di Fisica, INFN, I-35131 Padova (Italy); Pierroutsakou, D.; Romoli, M. [INFN Sezione di Napoli, I-80125, Napoli (Italy); Rusek, K. [Heavy Ion Laboratory, University of Warsaw, Pasteura 5a, PL-02-093 Warsaw (Poland)

2009-07-15

69

Curve Crossing for Low-Energy Elastic Scattering of He+ by Ne  

Microsoft Academic Search

The perturbation seen in the experimental differential elastic-scattering cross section for the 40-eV He+ + Ne system has been attributed to a single crossing of two intermolecular potential-energy curves. A new theoretical treatment of the curve-crossing problem, namely, that of Delos and Thorson, is employed to obtain the crossing probabilities and phases associated with the crossing. These are determined by

S. M. Bobbio; L. D. Doverspike; R. L. Champion

1973-01-01

70

Low-energy elastic electron scattering by acetaldehyde  

NASA Astrophysics Data System (ADS)

We report results from a combined experimental and computational study of low-energy electron interactions with acetaldehyde in the gas phase. Differential cross sections for elastic electron scattering were measured at selected incident energies from 1 to 50 eV, while corresponding first-principles calculations were carried out up to 30 eV. Integral and momentum-transfer cross sections were derived from the angle-differential data. The role of resonances in the scattering is examined and comparison is made to previous results for acetaldehyde and for its analogs, formamide and formic acid.

Gauf, A.; Navarro, C.; Balch, G.; Hargreaves, L. R.; Khakoo, M. A.; Winstead, C.; McKoy, V.

2014-02-01

71

Breakup and Elastic Scattering in the {sup 9}Be + {sup 144}Sm system at near barrier energies  

SciTech Connect

Breakup and elastic scattering in the Be + {sup 144}Sm system, at near barrier energies, are investigated. We calculate theoretically the non-capture breakup cross section by performing coupled reaction channel calculations. The energy dependence of the optical potential does not show the usual threshold anomaly found in tightly bound systems.

Paes, B.; Garcia, V. N.; Lubian, J.; Gomes, P. R. S. [Instituto de Fisica, Universidade Federal Fluminense, Niteroi, R.J., 24210-340 (Brazil); Padron, I. [CEADEN, P.O. Box 6122, Havana (Cuba)

2010-05-21

72

High Temperature Elastic Constants and the Evaluation of Effective Pair Potentials.  

National Technical Information Service (NTIS)

It is shown by example that the predicted temperature dependence of the elastic constants is a useful measure of the ability of an effective pair potential to estimate the high temperature thermal properties of a metal. Our example is based on a model pai...

R. D. Mountain D. C. Knauss

1979-01-01

73

Water Deficit Effects on Osmotic Potential, Cell Wall Elasticity, and Proline in Five Forage Grasses  

Microsoft Academic Search

Physiological responses of forage grasses to water deficit are not well documented, but may be important in determining drought resistance. The objective of this study was to determine the response of osmotic potential, leaf proline concentration, and cell wall elasticity to water deficit for the C4 (warm-season) grasses 'Nebraska 54' indiangrass [Sorghastrum nutans (L.) Nash], 'Pathfinder' switchgrass (Panicum virgutum L.),

D. J. Barker; C. Y. Sullivan; Lowell E. Moser

1993-01-01

74

Low Energy Elastic Electron Scattering from Gaseous Isopropanol  

NASA Astrophysics Data System (ADS)

Normalized absolute experimental electron scattering differential cross-sections (DCS) for electron energies of 1.5eV to 30eV and scattering angles from 10^o to 130^o, for elastic electron scattering from isopropyl alcohol will be presented. The experimental method employs the relative flow method using an aperture gas collimator source of isopropanol and helium as the calibration gas. It also employs a moveable source arrangement to accurately determine the experimental background. The theory is a multi-channel Schwinger method with polarization effects included. On average, agreement between theory and experiment is found to be very good.

Jo, Amos; Gauf, Alexsander; Tanner, Joshua; Hargreaves, Leigh R.; Khakoo, Murtadha A.; Winstead, Carl; McKoy, B. Vincent; Bettega, Marcio H. F.

2011-11-01

75

Energy Release Rate of Interface Delamination Between a Thin Coating and AN Elastic Substrate  

NASA Astrophysics Data System (ADS)

The mechanical properties of materials such as elastic modulus, hardness, and fracture toughness, can be measured by nanoindentation. For a thin film coated on an elastic substrate, the cross-sectional nanoindentation technique can decrease the influence of plastic deformation around the nanoindenter apex on fracture toughness for interface delamination. Considering the effect of the elastic substrate, the theory of an elastic beam bonded to an elastic foundation is further developed to obtain the energy release rate of interfacial debonding. Explicit closed-form solutions are determined, and the influence of the substrate on the energy release rate is shown graphically.

Duan, X.-Y.; Li, X.-F.

76

Elastic scattering of {sup 9}Li on {sup 208}Pb at energies around the Coulomb barrier  

SciTech Connect

We have studied the dynamical effects of the halo structure of {sup 11}Li on the scattering on heavy targets at energies around the Coulomb barrier. This experiment was performed at ISAC-II at TRIUMF with a world record in production of the post-accelerated {sup 11}Li beam. As part of this study we report here on the first measurement of the elastic cross section of the core nucleus, i.e. {sup 9}Li on {sup 208}Pb, at energies around the Coulomb barrier. A preliminary optical model analysis has been performed in order to extract a global optical potential to describe the measured angular distributions.

Cubero, M. [Instituto de Estructura de la Materia, CSIC, E-28006 Madrid (Spain); CICANUM, Universidad de Costa Rica, Apdo. 2060, San Jose (Costa Rica); Fernandez-Garcia, J. P.; Alvarez, M. A. G. [Departamento de FAMN, Universidad de Sevilla, Apdo. 1065, E-41080 Sevilla (Spain); Centro Nacional de Aceleradores, Avda. Thomas A. Edison, E-41092, Sevilla (Spain); Lay, J. A.; Moro, A. M. [Departamento de FAMN, Universidad de Sevilla, Apdo. 1065, E-41080 Sevilla (Spain); Acosta, L.; Martel, I.; Sanchez-Benitez, A. M. [Departamento de Fisica Aplicada, Facultad de Ciencias, Universidad de Huelva (Spain); Alcorta, M.; Borge, M. J. G.; Tengblad, O. [Instituto de Estructura de la Materia, CSIC, E-28006 Madrid (Spain); Buchmann, L.; Shotter, A.; Walden, P. [TRIUMF, V6T2A3 Vancouver B.C. (Canada); Diget, D. G.; Fulton, B. [Department of Physics, University of York, YO10 5DD Heslington, York (United Kingdom); Fynbo, H. O. U. [Department of Physics and Astronomy, University ofAarhus, DK-8000, Aarhus (Denmark); Galaviz, D. [Centro de Fisica Nuclear da Universidade de Lisboa, 1649-003 Lisbon (Portugal); Gomez-Camacho, J. [Centro Nacional de Aceleradores, Avda. Thomas A. Edison, E-41092, Sevilla (Spain); Departamento de FAMN, Universidad de Sevilla, Apdo. 1065, E-41080 Sevilla (Spain); Mukha, I. [Instituto de Fisica Corpuscular, CSIC-Universidadde Valencia (Spain)

2011-10-28

77

A proof of the cancellation of the redistribution tidal potential effects on the rotation of an elastic Earth model  

NASA Astrophysics Data System (ADS)

The gravitational action of the Moon and the Sun on the elastic Earth originates a redistribution of its mass. In turn, this redistribution is responsible of an additional term in the gravitational potential energy of the system, commonly referred to as tidal potential of redistribution. Its effects on the Earth rotation were previously discussed in Escapa et al. (2004) and Lambert & Mathews (2006). A numerical approach was followed in those works to show that for an elastic Earth model, assumed to be spherical and non-rotating in the undeformed state, there is no net contribution to the motion of the figure axis. This result is consistent with the corresponding one deduced from the torque approach, where one can derive analytically that the redistribution torque for that elastic Earth model vanishes (e.g., Krasinsky 1999). However, it is far from being a trivial question to recover the same result when working directly with the tidal potential of redistribution, as in Escapa et al. (2004) or Lambert & Mathews (2006). In this investigation we revisit the issue, enhancing and completing former results by Escapa et al. (2004). In particular, we aim at proving, by analytical means, that the redistribution tidal potential of the former elastic Earth model does not affect its rotational motion. To this end we expand that potential in terms of an Andoyer-like set of canonical variables, and then compute the torque associated to it. This choice was motivated by the suitability of this set of variables to extend our calculations to the nutations of other different elastic or anelastic Earth models, through the Hamiltonian framework (e.g., Ferrándiz et al. 2012). We show the exact cancellation of the derived expressions as a consequence of certain properties fulfilled by the expansions of the orbital motion of the perturbing bodies. Acknowledgement. - This work has been partially supported by the Spanish government trhough the MINECO projects I+D+I AYA201022039-C02-01, AYA2010-22039-C02-02, and Universidad de Alicante project GRE11-08. Escapa, A., Getino, J., & Ferrándiz, J. M. 2004, Proc. Journées Sys. Ref., Ed. N. Capitaine, Paris, 70 Ferrándiz, J. M., Baenas, T., & Escapa, A. 2012, Geophys. Res. Abs., 14, EGU2012-6175 Krasinsky, G. A. 1999, Celest. Mech. Dyn. Astron., 75, 39 Lambert, S. & Mathews, P. M. 2006, A&A, 453, 363

Baenas, Tomás; Escapa, Alberto; Ferrándiz, Jose Manuel

2014-05-01

78

Elastic calculation of self-interstitial formation energies in fcc metals  

Microsoft Academic Search

An elastic calculation of self-interstitial formation energies in fcc metals is presented. The formation energy of an interstitial is identified with the elastic deformation energy inside an infinite crystal containing an extra atom. The following configurations of interstitials in fcc metals are analyzed: octahedral and tetrahedral single interstitials and single , , and splits. The deformation resulting from the insertion

L. Kornblit

1980-01-01

79

Universality in Ground State Energy Distributions of Random Elastic Manifolds  

NASA Astrophysics Data System (ADS)

The distribution of ground state energies of elastic manifolds with random-bond disorder is studied numerically in (1+1), (1+2), (1+3), and (2+1) dimensions. (1+1) -dimensional manifolds, or directed polymers, are known to have in a ``single valley'' an energy distribution which is Gaussian close to the mean, and has stretched exponential low and high energy tails with the stretching exponents ?- = 1.6 and ?+ = 2.3 (J. A. Kim, M. A. Moore, and A. J. Bray, Phys. Rev. A 44), 2345 (1991).. With free or periodic boundary conditions, if the transverse height of the system is increased the ?-exponents vary continuosly and the energy distribution has an asymptotic cross-over to the Gumbel distribution of extreme statistics. For all the cases, including the (2+1)-dimensional random bond Ising domain wall one, it is found that the ?-exponents corresponding to a single-valley boundary condition are hyper-universal, close to those from (1+1) dimensions. This is in contrast to the scaling of the width of the distribution, characterized by the energy fluctuation exponent ? which depends on dimensionality. Acknowledgment: This work was performed under the auspices of the US Dept. of Energy at the University of California/Lawrence Livermore National Laboratory under contract no. W-7405-Eng-48.

Seppälä, Eira T.; Kytölä, Kalle P.; Alava, Mikko J.

2002-03-01

80

Target Flexibility in RNA-Ligand Docking Modeled by Elastic Potential Grids  

PubMed Central

The highly flexible nature of RNA provides a formidable challenge for structure-based drug design approaches that target RNA. We introduce an approach for modeling target conformational changes in RNA?ligand docking based on potential grids that are represented as elastic bodies using Navier's equation. This representation provides an accurate and efficient description of RNA?ligand interactions even in the case of a moving RNA structure. When applied to a data set of 17 RNA?ligand complexes, filtered out of the largest validation data set used for RNA?ligand docking so far, the approach is twice as successful as docking into an apo structure and still half as successful as redocking to the holo structure. The approach allows considering RNA movements of up to 6 Å rmsd and is based on a uniform and robust parametrization of the properties of the elastic potential grids, so that the approach is applicable to different RNA?ligand complex classes.

2011-01-01

81

The elastic relaxation energy and equilibrium aspect ratio of self-organized pyramidal quantum dot  

Microsoft Academic Search

The formation of dislocation-free three-dimensional island by heteroepitaxial growth of lattice-mismatched materials is used to produce quantum dots. The equilibrium shape of these islands results from the competition between surface and elastic energies. The system Ge\\/Si has been studied in detail. The elastic relaxation energy of the islands has been calculated within a continuum elasticity theory using finite element method,

Wang Min Zhou; Cheng Yu Cai; Shu Yuan Yin; Chong Yu Wang

2008-01-01

82

Anchoring energy and orientational elasticity of a ferroelectric liquid crystal  

SciTech Connect

The dielectric susceptibility of a helix-free ferroelectric liquid crystal layer has been experimentally and theoretically studied as a function of the layer thickness. The investigation has been performed on the inner branch of the polarization hysteresis loop, in the region of a linear dependence of the polarization on the electric field. The experimental results are explained using the notion of effective layer thickness, which involves the characteristic distance {xi} over which the orienting effect of interfaces is operative. Comparison of the experimental data and theoretical results made it possible to estimate this distance as {xi} = 41 {mu}m and evaluate the anchoring energy (W = 2.8 Multiplication-Sign 10{sup -3}-1.1 Multiplication-Sign 10{sup -2} J/m{sup 2}) and the intralayer elastic constant (K Double-Prime Almost-Equal-To 1 Multiplication-Sign 10{sup -8}-3 Multiplication-Sign 10{sup -7} N).

Kaznacheev, A. V., E-mail: kazna@ineos.ac.ru [Russian Academy of Sciences, Nesmeyanov Institute of Organoelement Compounds (Russian Federation); Pozhidaev, E. P., E-mail: epozhidaev@mail.ru [Russian Academy of Sciences, Lebedev Physical Institute (Russian Federation)

2012-06-15

83

Final Governing Equation of Plane Elasticity of Icosahedral Quasicrystals and General Solution Based on Stress Potential Function  

Microsoft Academic Search

The stress potential function theory for plane elasticity of icosahedral quasicrystals is developed. By introducing stress functions, huge numbers of basic equations involving elasticity of icosahedral quasicrystals are reduced to a single partial differential equation of the 12th order. The general solution of the equation is expressed by 6 analytic functions of complex variable z = x+iy.

Lian-He Li; Tian-You Fan

2006-01-01

84

Microscopic study on proton elastic scattering of light exotic nuclei at energies below than 100 MeV/nucleon  

NASA Astrophysics Data System (ADS)

The proton elastic scattering data on some light exotic nuclei, namely, 6, 8He, 9, 11Li, and 10, 11, 12Be, at energies below than 100MeV/nucleon are analyzed using the single folding optical model. The real, imaginary, and spin-orbit parts of the optical potential (OP) are constructed only from the folded potentials and their derivatives using M3Y effective nucleon-nucleon interaction. These OP parts, their renormalization factors and their volume integrals are studied. The surface and spin-orbit potentials are important to fit the experimental data. Three model densities for halo nuclei are used and the sensitivity of the cross-sections to these densities is tested. The imaginary OP within high-energy approximation is used and compared with the single folding OP. This OP with few and limited fitting parameters, which have systematic behavior with incident energy, successfully describes the proton elastic scattering data with exotic nuclei.

Farag, M. Y. H.; Esmael, E. H.; Maridi, H. M.

2012-11-01

85

Investigating Kinetic and Potential Energy  

NSDL National Science Digital Library

Students use media resources and an in-class investigation to explore the types of energy within different types of systems. They also use the formulas for kinetic and potential energy to examine the path of a projectile.

Foundation, Wgbh E.

2007-04-19

86

Magneto-elasticity in hydrogels containing Fe3O4 nanoparticles and their potential applications  

NASA Astrophysics Data System (ADS)

The magnetic hydrogels have been fabricated via standard method of polymer preparation. Hydrogels were the mixture of polyvinyl alcohol (PVA) and water by certain ratio of mass. Magnetism in hydrogels was presented by introduction of magnetic Fe3O4 nanoparticles with crystal size ranging from 11 nm to 15 nm, prepared by coprecipitation technique from iron-sands. According to the magnetic induction experiment, it has shown that the magneto-elasticity of gels containing Fe3O4 of around 2.5% - 15% tends to decrease as increasing Fe3O4 concentration. The magneto-elasticity responses of the gels clearly form hysteresis in the increasing and decreasing applied magnetic field, where in turn open the potential applications of these magnetic hydrogels.

Sunaryono; Taufiq, Ahmad; Munaji; Indarto, Bahtera; Triwikantoro; Zainuri, Mochamad; Darminto

2013-09-01

87

Microscopic optical potential for {alpha}-nucleus elastic scattering in a Dirac-Brueckner-Hartree-Fock approach  

SciTech Connect

The microscopic optical model potential (OMP) of {alpha}-nucleus elastic scattering based on a double-folding model (DFM) is studied. The nucleon OMPs in nuclear matter as well as the nucleon-nucleon (NN) effective interaction are calculated in the framework of the Dirac-Brueckner-Hartree-Fock (DBHF) approach, in which the density and energy dependence is parametrized by polynomial expansions. The microscopic OMP of nucleus-nucleus scattering is obtained by doubly folding the complex NN effective interaction with respect to the densities of both projectile and target nuclei. An improved local-density approximation is adopted to take account of the finite-range correction. Renormalization factors on the real and imaginary OMP are introduced to obtain the best fit to the experimental data. A systematic analysis of {sup 4}He elastic scattering off {sup 12}C, {sup 16}O, {sup 28}Si, and {sup 40}Ca is performed. The calculated cross sections over a wide range of incident energies and scattering angles are in good agreement with the experimental data, which confirms the applicability of this model. Moreover, for the same projectile and target, the renormalization factors are found to be almost constant at various incident energies.

Zou Wei [China Institute of Atomic Energy, P.O. Box 275(18), Beijing 102413 (China); Department of Physics, Jilin University, Jilin 130023 (China); Tian Yuan [China Institute of Atomic Energy, P.O. Box 275(18), Beijing 102413 (China); Ma Zhongyu [China Institute of Atomic Energy, P.O. Box 275(18), Beijing 102413 (China); Center of Theoretical Nuclear Physics, National Laboratory of Heavy Collision, Lanzhou 730000 (China)

2008-12-15

88

The elastic modulus correction term in creep activation energies Applied to oxide dispersion strengthened superalloy  

NASA Technical Reports Server (NTRS)

The effect of elastic modulus and the temperature dependence of elastic modulus on creep activation energies for an oxide dispersion strengthened nickel-base superalloy are investigated. This superalloy is commercially known as Inconel Alloy MA 753, strengthened both by gamma-prime precipitates and by yttria particles. It is shown that at intermediate temperatures, say below 1500 F, where elastic modulus is weakly dependent on temperature, the modulus correction term to creep activation energy is small. Accordingly, modulus corrections are insignificant for the superalloy considered, which shows high apparent creep activation energies at this temperature. On the contrary, at very high temperatures, the elastic modulus correction term can be significant, thus reducing the creep activation energy to that of vacancy self-diffusion. In order to obtain high-temperature creep resistance, a high-value elastic modulus with a weak dependence on temperature is required.

Malu, M.; Tien, J. K.

1975-01-01

89

Direct determination of multi-axial elastic potentials for incompressible elastomeric solids: an accurate, explicit approach based on rational interpolation  

NASA Astrophysics Data System (ADS)

With a novel approach based on certain logarithmic invariants, we demonstrate that a multi-axial elastic potential for incompressible, isotropic rubber-like materials may be obtained directly from two one-dimensional elastic potentials for uniaxial case and simple shear case, in a sense of exactly matching finite strain data for four benchmark tests, including uniaxial extension, simple shear, bi-axial extension, and plane-strain extension. As such, determination of multi-axial elastic potentials may be reduced to that of two one-dimensional elastic potentials. We further demonstrate that the latter two may be obtained by means of rational interpolating procedures for uniaxial data and shear data displaying strain-stiffening effects. Numerical examples are presented in fitting Treloar's data and other data.

Zhang, Yu-Yu; Li, Hao; Wang, Xiao-Ming; Yin, Zheng-Nan; Xiao, Heng

2014-03-01

90

Energy decaying scheme for nonlinear elastic multi-body systems  

Microsoft Academic Search

This paper is concerned with the modeling of nonlinear elastic multi-body systems discretized using the finite element method. The formulation uses Cartesian coordinates to represent the position of each elastic body with respect to a single inertial frame. The kinematic constraints among the various bodies of the system are enforced via the Lagrange multiplier technique. The resulting equations of motion

O. A. Bauchau; N. J. Theron

1996-01-01

91

Analysis of Dermal Elastic Fibers in the Absence of Fibulin-5 Reveals Potential Roles for Fibulin-5 in Elastic Fiber Assembly  

PubMed Central

Fibulin-5 is a 66 kDa modular, extracellular matrix protein that localizes to elastic fibers. Although in vitro protein-protein binding studies have shown that fibulin-5 binds many proteins involved in elastic fiber formation, the specific role of fibulin-5 in elastogenesis remains unclear. To provide a more detailed analysis of elastic fiber assembly in the absence of fibulin-5, the dermis of wild-type and fibulin-5 gene knockout (Fbln5?/?) mice was examined with electron microscopy (EM). Although light microscopy showed apparently normal elastic fibers near the hair follicles and the absence of elastic fibers in the intervening dermis of the Fbln5?/? mouse, EM revealed the presence of aberrantly assembled elastic fibers in both locales. Instead of the elastin being incorporated into the microfibrillar scaffold, the elastin appeared as globules juxtaposed to the microfibrils. Desmosine analysis showed significantly lower levels of mature cross-linked elastin in the the Fbln5?/? dermis, however, gene expression levels for tropoelastin and fibrillin-1, the major elastic fiber components, were unaffected. Based on these results, the nature of tropoelastin cross-linking was investigated using domain specific antibodies to lysyl oxidase like-1 (LOXL-1). Immunolocalization with an antibody to the N-terminal pro-peptide, which is cleaved to generate the active enzyme, revealed abundant staining in the Fbln5?/? dermis and no staining in the wild-type dermis. Overall, these results suggest two previously unrecognized functions for fibulin-5 in elastogenesis; first, to limit the extent of aggregation of tropoelastin monomers and/or coacervates and aid in the incorporation of elastin into the microfibril bundles, and second, to potentially assist in the activation of LOXL-1.

Choi, Jiwon; Bergdahl, Andreas; Zheng, Qian; Starcher, Barry; Yanagisawa, Hiromi; Davis, Elaine C.

2009-01-01

92

Analysis of dermal elastic fibers in the absence of fibulin-5 reveals potential roles for fibulin-5 in elastic fiber assembly.  

PubMed

Fibulin-5 is a 66 kDa modular, extracellular matrix protein that localizes to elastic fibers. Although in vitro protein-protein binding studies have shown that fibulin-5 binds many proteins involved in elastic fiber formation, the specific role of fibulin-5 in elastogenesis remains unclear. To provide a more detailed analysis of elastic fiber assembly in the absence of fibulin-5, the dermis of wild-type and fibulin-5 gene knockout (Fbln5(-/-)) mice was examined with electron microscopy (EM). Although light microscopy showed apparently normal elastic fibers near the hair follicles and the absence of elastic fibers in the intervening dermis of the Fbln5(-/-) mouse, EM revealed the presence of aberrantly assembled elastic fibers in both locales. Instead of the elastin being incorporated into the microfibrillar scaffold, the elastin appeared as globules juxtaposed to the microfibrils. Desmosine analysis showed significantly lower levels of mature cross-linked elastin in the Fbln5(-/-) dermis, however, gene expression levels for tropoelastin and fibrillin-1, the major elastic fiber components, were unaffected. Based on these results, the nature of tropoelastin cross-linking was investigated using domain specific antibodies to lysyl oxidase like-1 (LOXL-1). Immunolocalization with an antibody to the N-terminal pro-peptide, which is cleaved to generate the active enzyme, revealed abundant staining in the Fbln5(-/-) dermis and no staining in the wild-type dermis. Overall, these results suggest two previously unrecognized functions for fibulin-5 in elastogenesis; first, to limit the extent of aggregation of tropoelastin monomers and/or coacervates and aid in the incorporation of elastin into the microfibril bundles, and second, to potentially assist in the activation of LOXL-1. PMID:19321153

Choi, Jiwon; Bergdahl, Andreas; Zheng, Qian; Starcher, Barry; Yanagisawa, Hiromi; Davis, Elaine C

2009-05-01

93

Dynamics of energy exchange in model samples subjected to elastic and electromagnetic impacts  

NASA Astrophysics Data System (ADS)

The effects of elastic and electromagnetic (EM) fields are studied as an additional factor of energy exchange in the process of the deformation of a heterogeneous medium. The threshold value of initiating energy, Ktr( kp), relative to the current relaxation process is quantitatively estimated. It is shown that the estimated energy impacts below the threshold can initiate relaxation of local structural stresses and, thus, reduce the risk of a macrofracture. In a seismically active region, a similar scenario of initiation of dynamic development is considered in the local zones of potential sources of earthquakes. The possibility to determine the location, the time, and the intensity of the initiating EM impact is considered. From the experiments, the coefficient of electromechanical conversion is calculated.

Avagimov, A. A.; Zeigarnik, V. A.; Okunev, V. I.

2011-10-01

94

Elastic and vibrational properties of group IV semiconductors in empirical potential modelling.  

PubMed

We have developed an interatomic potential that with a single set of parameters is able to accurately describe at the same time the elastic, vibrational and thermodynamics properties of semiconductors. The simultaneous inclusion of radial and angular forces of the interacting atom pairs (short range) together with the influence of the broken crystal symmetry when the atomic arrangement is out of equilibrium (long range) results in correct predictions of all of the phonon dispersion spectrum and mode-Grüneisen parameters of silicon and germanium. The long range interactions are taken into account up to the second nearest neighbours, to correctly influence the elastic and vibrational properties, and therefore represent only a marginal computational cost compared to the full treatment of other proposed potentials.Results of molecular dynamics simulations are compared with those of ab initio calculations, showing that when our proposed potential is used to perform the initial stages of the structural relaxation, a significant reduction of the computational time needed during the geometry optimization of density functional theory simulations is observed. PMID:24065386

Monteverde, U; Migliorato, M A; Pal, J; Powell, D

2013-10-23

95

REFLECTION AND TRANSMISSION OF THE ENERGY OF TRANSIENT ELASTIC EXTENSIONAL WAVES IN A BENT BAR  

Microsoft Academic Search

Reflection and transmission of the energy of a transient elastic extensional wave at a sharp or smooth bend of a bar are studied theoretically and experimentally, with the principal aim being to validate the model used by Wu and Lundberg in a parallel study of harmonic elastic waves. In this model effects of rotary inertia and shear deformation are neglected,

R. Beccu; C. M. Wu; B. Lundberg

1996-01-01

96

Systematic study of the ?-optical potential via elastic scattering near the Z=50 region for p-process nuclei  

NASA Astrophysics Data System (ADS)

Production of proton-rich nuclei beyond iron in stars proceeds via the p process, i.e., a sequence of photodisintegration reactions, (?,n), (?,p), and (?,?) on heavy nuclei at temperatures of 2-3×109 K. The involved reaction rates are typically calculated with the statistical Hauser-Feshbach (HF) model. However, the HF model performs poorly in calculating the critical (?,?) rates due to the uncertainty of the alpha optical potentials applied. To test the reliability of the HF calculations and provide a systematic understanding of the ? optical potential at energies of astrophysical interest, a series of precision ? scattering measurements were carried out at the Notre Dame FN Tandem Accelerator. Specifically, 106Cd, 118Sn, and 120,124,126,128,130Te were studied at energies both below and above the Coulomb barrier. A new parametrization of the ? optical potential was derived of the elastic scattering cross section data. The derived potential was applied for calculating the ?-induced reaction cross sections on these nuclei using the HF approach. The results were compared to the corresponding experimental values obtained from previous activation measurements on Cd, Sn, and Te isotopes.

Palumbo, A.; Tan, W. P.; Görres, J.; Best, A.; Couder, M.; Crowter, R.; deBoer, R. J.; Falahat, S.; LeBlanc, P. J.; Lee, H. Y.; O'Brien, S.; Strandberg, E.; Wiescher, M.; Greene, J. P.; Fülöp, Zs.; Kiss, G. G.; Somorjai, E.; Özkan, N.; Efe, G.; Güray, R. T.

2012-03-01

97

Interaction of rare gas metastable atoms. [Differential and total cross sections, elastic scattering, ionization, potential scattering, phase shifts, rate constants  

SciTech Connect

The physical and chemical properties of metastable rare gas atoms are discussed and summarized. This is followed by a detailed examination of the various possible pathways whereby the metastable's excess electronic energy can be dissipated. The phenomenon of chemi-ionization is given special emphasis, and a theoretical treatment based on the use of complex (optical) potential is presented. This is followed by a discussion on the unique advantages offered by elastic differential cross section measurements in the apprehension of the fundamental forces governing the ionization process. The methodology generally adopted to extract information about the interaction potential for scattering data is also systematically outlined. Two widely studied chemi-ionization systems are then closely examined in the light of accurate differential cross section measurements obtained in this work. The first system is He(2/sup 3/S) + Ar for which one can obtain an interaction potential which is in good harmony with the experimental results of other investigators. The validity of using the first-order semiclassical approximation for the phase shifts calculation in the presence of significant opacities is also discussed. The second reaction studied is He*+D/sub 2/ for which measurements were made on both spin states of the metastable helium. A self-consistent interaction potential is obtained for the triplet system, and reasons are given for not being able to do likewise for the singlet system. The anomalous hump proposed by a number of laboratories is analyzed. Total elastic and ionization cross sections as well as rate constants are calculated for the triplet case. Good agreement with experimental data is found. Finally, the construction and operation of a high power repetitively pulsed nitrogen laser pumped dye laser system is described in great details. Details for the construction and operation of a flashlamp pumped dye laser are likewise given.

Wang, A.Z.F.

1977-11-01

98

Partial-wave analysis for elastic p{sup 13}C scattering at astrophysical energies  

SciTech Connect

A standard partial-wave analysis was performed on the basis of known measurements of differential cross sections for elastic p{sup 13}C scattering at energies in the range 250-750 keV. This analysis revealed that, in the energy range being considered, it is sufficient to take into account the {sup 3}S{sub 1} wave alone. A potential for the triplet {sup 3}S{sub 1}-wave state of the p{sup 13}C system in the region of the J{sup p}T = 1{sup -1} resonance at 0.55 MeV was constructed on the basis of the phase shifts obtained from the aforementioned partial-wave analysis.

Dubovichenko, S. B., E-mail: dubovichenko@mail.ru [V.G. Fessenkov Astrophysical Institute (Kazakhstan)

2012-03-15

99

Elastic energy distribution in bi-material lithosphere: implications for shear zone formation  

NASA Astrophysics Data System (ADS)

Shear instability in the lithosphere can cause mechanical rupturing such as slab detachment and deep focus earthquake. Recent studies reported that bi-material interface, which refers to sharp elastic modulus contrast, plays an important role in triggering the instability [So and Yuen et al., 2012, GJI]. In present study, we performed two-dimensional numerical simulations to investigate the distribution of thermal-mechanical energy within the bi-material lithosphere. Under the far-field constant compression exerted on the domain, a larger elastic energy is accumulated into the compliant part than stiff medium. For instance, the compliant part has two times greater elastic energy density than surrounding stiff part, when the elastic modulus contrast between two different parts is five. Although these elastic energies in both parts are conversed into thermal energies after plastic yielding, denser elastic energy in the compliant is released more efficiently. This leads to efficient strength weakening and the subsequent ductile shear zone in the compliant part. We propose that strong shear heating occurs in lithosphere with the bi-material interface due to locally non-uniform distribution of the energy around the interface.

So, B.; Yuen, D. A.

2013-12-01

100

LHC Physics Potential versus Energy  

SciTech Connect

Parton luminosities are convenient for estimating how the physics potential of Large Hadron Collider experiments depends on the energy of the proton beams. I present parton luminosities, ratios of parton luminosities, and contours of fixed parton luminosity for gg, u{bar d}, and qq interactions over the energy range relevant to the Large Hadron Collider, along with example analyses for specific processes.

Quigg, Chris; /Fermilab

2009-08-01

101

Elastic energy loss with respect to the reaction plane in a Monte Carlo model  

SciTech Connect

We present a computation of {pi}{sup 0} nuclear modification factor with respect to the reaction plane in Au+Au collisions at {radical}(s{sub NN})=200 GeV, based on a Monte Carlo model of elastic energy loss of hard partons traversing the bulk hydrodynamical medium created in ultrarelativistic heavy-ion collisions. We find the incoherent nature of elastic energy loss incompatible with the measured data.

Auvinen, Jussi; Eskola, Kari J.; Holopainen, Hannu; Renk, Thorsten [Department of Physics, P.O. Box 35, University of Jyvaeskylae, FI-40014 Jyvaeskylae, Finland and Helsinki Institute of Physics, P.O. Box 64, University of Helsinki, FI-00014 Helsinki (Finland)

2010-11-15

102

A derivation of linear elastic energies from pair-interaction atomistic systems  

Microsoft Academic Search

Pair-interaction atomistic energies may give rise, in the framework of the passage from discrete systems to continuous variational problems, to nonlinear energies with genuinely quasiconvex integrands. This phenomenon takes place even for simple harmonic interactions as shown by an example by Friesecke and Theil (19). On the other hand, a rigorous derivation of linearly elastic energies from energies with quasiconvex

Andrea Braides; Margherita Solci; Enrico Vitali

2007-01-01

103

Size-induced elastic stiffening of ZnO nanostructures: Skin-depth energy pinning  

NASA Astrophysics Data System (ADS)

It has long been puzzling regarding the trends and physical origins of the size-effect on the elasticity of ZnO nanostructures. An extension of the atomic ``coordination-radius'' correlation premise of Pauling and Goldschmidt to energy domain has enabled us to clarify that the elastic modulus is intrinsically proportional to the sum of bond energy per unit volume and that the size-induced elastic stiffening arises from (i) the broken-bond-induced local strain and skin-depth energy pinning and (ii) the tunable fraction of bonds between the undercoordinated atoms, and therefore, the elastic modulus of ZnO nanostructures should increase with the inverse of feature size.

Liu, X. J.; Li, J. W.; Zhou, Z. F.; Yang, L. W.; Ma, Z. S.; Xie, G. F.; Pan, Y.; Sun, Chang Q.

2009-03-01

104

Characterization of Elastic Properties in Basalts of the Western Snake River Plain, Idaho: a Mechanostratigraphic Analysis of a Potential Geothermal Reservoir  

NASA Astrophysics Data System (ADS)

The western Snake River Plain is a region of high crustal heat flow and has the potential for commercial geothermal energy development. High-temperature crystalline reservoirs commonly have connected fracture networks and other discontinuities that provide the primary fluid storage and permeability (Type I fractures). A borehole was drilled during the DOE/ICDP Snake River Scientific Drilling Program near Mountain Home, Idaho to a depth of ~1,800 m (6,000 ft) with 85 - 90% slimhole core recovery to assess the potential for geothermal energy development. A high-temperature artesian flow zone was encountered in basalt at a depth of 1,745 m (5,726 ft) in the MH-2 borehole with fluid temperatures above 140°C (240°F). Analysis of geomechanical behavior of rocks requires an understanding of basic physical and elastic properties under dynamic in-situ stress conditions. Here we conduct unconfined uniaxial compressive stress experiments on core samples to measure static elastic properties and compressive strength over a ~305 m (1,000 ft) interval of the borehole above and including the geothermal reservoir. Acoustic velocities are measured under pressure and temperature scenarios to calculate dynamic elastic properties and describe the anisotropy of elastic moduli and compressive strength. Dynamic elastic properties are calculated from dipole sonic borehole log data and compare the results to the previous dynamic and static interpretations. The comparison demonstrates that the calculation of dynamic elastic properties from borehole data is an effective method to interpret and describe mechanical stratigraphy and elastic properties in the case that core is not available for analysis in this area. Natural fractures, induced fractures, and breakouts are mapped in acoustic televiewer data. Fracture density is calculated and compared to lithological and mechanical stratigraphy, defined by the physical properties, elastic properties, and strength measurements. The stratigraphic relationships indicate that a ~15 m (50 ft) section of weak, non-brittle, low-permeability, highly altered basalt may act as a caprock to the geothermal reservoir at depth. Lithological descriptions of core show that the basalt in MH-2 has been altered and reworked in many cases. The alternating zones of ductile rocks and brittle basalts affect fracture density and can control fracture permeability. The induced fracture and breakout data are used to identify the direction of each of the two horizontal principal stresses. Interpretation of breakout data and induced fracture data indicate that the maximum horizontal principal stress (Shmax) is oriented 50° + 15°. This direction is antithetical to the expected Shmax direction based on the orientation of the normal fault-bounded basin that is oriented approximately 320°.

Kessler, J. A.; Evans, J. P.; Schmitt, D. R.; Shervais, J. W.

2013-12-01

105

Analysis of Low-Energy K(+)-P Elastic Scattering.  

National Technical Information Service (NTIS)

An analysis based on dispersion-relation techniques is applied to experimental data for K(+)-p elastic scattering. Particular reference is made to the 'force of longest range' due to the exchange of low-mass pion pairs with isospin I=0. The effect of this...

A. D. Martin T. D. Spearman

1964-01-01

106

A constitutive framework based on elastic and internal energy degradation  

Microsoft Academic Search

A general constitutive framework is presented capable of representing different irreversible deformation modes, like plasticity, elastic damage, complex evolution of the hardening properties and the induced coupling effects. The formulation can be framed in the generalized standard material models with internal variables and multiple dissipative activation functions. The formulation is thermodynamically consistent and the state laws, the structure of the

G. Borino; S. Del Linz; G. Giambanco

2001-01-01

107

Cross-linking cellulose nanofibrils for potential elastic cryo-structured gels.  

PubMed

Cellulose nanofibrils were produced from P. radiata kraft pulp fibers. The nanofibrillation was facilitated by applying 2,2,6,6-tetramethylpiperidinyl-1-oxyl-mediated oxidation as pretreatment. The oxidized nanofibrils were cross-linked with polyethyleneimine and poly N-isopropylacrylamide-co-allylamine-co-methylenebisacrylamide particles and were frozen to form cryo-structured gels. Samples of the gels were critical-point dried, and the corresponding structures were assessed with scanning electron microscopy. It appears that the aldehyde groups in the oxidized nanofibrils are suitable reaction sites for cross-linking. The cryo-structured materials were spongy, elastic, and thus capable of regaining their shape after a given pressure was released, indicating a successful cross-linking. These novel types of gels are considered potential candidates in biomedical and biotechnological applications. PMID:22152032

Syverud, Kristin; Kirsebom, Harald; Hajizadeh, Solmaz; Chinga-Carrasco, Gary

2011-01-01

108

Cross-linking cellulose nanofibrils for potential elastic cryo-structured gels  

NASA Astrophysics Data System (ADS)

Cellulose nanofibrils were produced from P. radiata kraft pulp fibers. The nanofibrillation was facilitated by applying 2,2,6,6-tetramethylpiperidinyl-1-oxyl-mediated oxidation as pretreatment. The oxidized nanofibrils were cross-linked with polyethyleneimine and poly N-isopropylacrylamide- co-allylamine- co-methylenebisacrylamide particles and were frozen to form cryo-structured gels. Samples of the gels were critical-point dried, and the corresponding structures were assessed with scanning electron microscopy. It appears that the aldehyde groups in the oxidized nanofibrils are suitable reaction sites for cross-linking. The cryo-structured materials were spongy, elastic, and thus capable of regaining their shape after a given pressure was released, indicating a successful cross-linking. These novel types of gels are considered potential candidates in biomedical and biotechnological applications.

Syverud, Kristin; Kirsebom, Harald; Hajizadeh, Solmaz; Chinga-Carrasco, Gary

2011-12-01

109

Elastic scattering of electrons on Ne atoms at intermediate energies  

NASA Astrophysics Data System (ADS)

In this work, we present a theoretical study on electron scattering by Ne in the intermediate- and high-energy range. More specifically, we report calculated differential cross sections for electron scattering by Ne in the 20-500 eV range by the Schwinger multichannel method using plane waves as a trial basis set. To include exchange plus polarization effects, we used the Born-Ochkur model and the Buckingham potential, respectively. The comparison of our calculated results with experimental data and recent theoretical studies (Jablonski et al 2004 J. Phys. Chem. Ref. Data 33 409) is encouraging.

Lino, Jorge L. S.

2010-03-01

110

Ab initio Potential Energy Surface for H-H2  

NASA Technical Reports Server (NTRS)

Ab initio calculations employing large basis sets are performed to determine an accurate potential energy surface for H-H2 interactions for a broad range of separation distances. At large distances, the spherically averaged potential determined from the calculated energies agrees well with the corresponding results determined from dispersion coefficients; the van der Waals well depth is predicted to be 75 +/- (mu)E(sub h). Large basis sets have also been applied to reexamine the accuracy of theoretical repulsive potential energy surfaces. Multipolar expansions of the computed H-H2 potential energy surface are reported for four internuclear separation distances (1.2, 1.401, 1.449, and 1.7a(sub 0) of the hydrogen molecule. The differential elastic scattering cross section calculated from the present results is compared with the measurements from a crossed beam experiment.

Partridge, Harry; Bauschlicher, Charles W., Jr.; Stallcop, James R.; Levin, Eugene

1993-01-01

111

Effect of size on energy and elastic constants of Ni nanoparticles studied using the embedded-atom method  

NASA Astrophysics Data System (ADS)

Using the embedded-atom method potential, the energy and elastic constants of Ni nanoparticles are investigated as a function of size. It is found that a simple formula derived from the total energy can be used to explain the change characteristics of the size-dependent energy and C11 and C44 of Ni nanoparticles. The change characteristics of the size-dependent C12 are slightly different from the situation of C11 and C44 and they perhaps depend on its strain character when the nanoparticle is larger than ˜2.0 nm in size. It is also found that a transition occurs from a fast change of these size-dependent properties to a slow one. Such a transition occurs at ˜1.5 nm in size for the nanoparticles, i.e. the energy and elastic constants of Ni nanoparticles show approximately no change as long as their size is larger than 2 nm. It is also demonstrated that when the size of the nanoparticle is large enough (>20 nm) the calculated elastic constants and the cohesive energy are in agreement with those of their respective bulk counterpart.

Cai, Jun; Wang, Yan-Dong; Huang, Zhen-wei

2013-04-01

112

Monte Carlo Simulation of Ferroelectric Domain Structure: Electrostatic and Elastic Strain Energy Contributions  

Microsoft Academic Search

A lattice-Monte Carlo approach was developed to simulate ferroelectric domain behav- ior. The model utilizes a Hamiltonian for the total energy that includes electrostatic terms (involving dipole-dipole interactions, local polarization gradients, and applied electric field), and elastic strain energy. The contributions of these energy components to the domain structure and to the overall ap- plied field response of the system

B. G. Potter; B. A. Tuttle; V. Tikare

113

Monte Carlo simulation of ferroelectric domain structure: Electrostatic and elastic strain energy contributions  

Microsoft Academic Search

A lattice-Monte Carlo approach was developed to simulate ferroelectric domain behavior. The model utilizes a Hamiltonian for the total energy that includes electrostatic terms (involving dipole-dipole interactions, local polarization gradients, and applied electric field), and elastic strain energy. The contributions of these energy components to the domain structure and to the overall applied field response of the system were examined.

B. G. Potter; B. A. Tuttle; V. Tikare

2000-01-01

114

Variation of the energy release rate as a crack approaches and passes through an elastic inclusion  

NASA Technical Reports Server (NTRS)

The variation of the energy release rate (ERP) at the tip of a crack penetrating an elastic inclusion is analyzed using an approach involving modeling the random array of microcracks or other defects by an elastic inclusion with effective elastic properties. Computations are carried out using a finite element procedure. The eight-noded isoparametric serendipity element with the shift of the midpoint to the quarter-point is used to simulate the singularity at the crack tip, and the crack growth is accommodated by implementing a mesh regeneration technique. The ERP values were calculated for various crack tip positions which simulate the process of the crack approaching and penetrating the inclusion.

Li, Rongshun; Chudnovsky, A.

1993-01-01

115

Kinetic and Potential Energy of Motion  

NSDL National Science Digital Library

In this lesson, students are introduced to both potential energy and kinetic energy as forms of mechanical energy. A hands-on activity demonstrates how potential energy can change into kinetic energy by swinging a pendulum, illustrating the concept of conservation of energy. Students calculate the potential energy of the pendulum and predict how fast it will travel knowing that the potential energy will convert into kinetic energy. They verify their predictions by measuring the speed of the pendulum.

Integrated Teaching And Learning Program

116

Examining the Potential of Renewable Energy  

SciTech Connect

This outreach document goes to potential partners for NREL's Renewable Energy Potential Initiative, which will explore the long-term potential of Renewable Energy to meet a substantial share of U.S. energy needs.

Not Available

2006-09-01

117

The curvature elastic-energy function of the lipid-water cubic mesophase  

NASA Astrophysics Data System (ADS)

CELL and lipid membranes are able to bend, as manifested during membrane fusion and the formation of non-lamellar lyotropic mesopbases in water. But there is an energy cost to bending of lipid layers, called the curvature elastic energy. Although the functional form of this energy is known1, a complete quantitative knowledge of the curvature elastic energy, which is central to predicting the relative stability of the large number of phases that lipid membranes can adopt, has been lacking. Here we use X-ray synchrotron diffraction measurements of the variation of lattice parameter with pressure and temperature for the periodic Ia3d (Q230) cubic phase of hydrated monoolein to calculate the complete curvature elastic-energy function for the lipid cubic mesophase. This allows us to predict the stabilities of different cubic and lamellar phases for this system as a function of composition.

Chung, Hesson; Caffrey, Martin

1994-03-01

118

A boundary element method for solving 3D static gradient elastic problems with surface energy  

Microsoft Academic Search

A boundary element methodology is developed for the static analysis of three-dimensional bodies exhibiting a linear elastic\\u000a material behavior coupled with microstructural effects. These microstructural effects are taken into account with the aid\\u000a of a simple strain gradient elastic theory with surface energy. A variational statement is established to determine all possible\\u000a classical and non-classical (due to gradient with surface

K. G. Tsepoura; S. Papargyri-Beskou; D. Polyzos

2002-01-01

119

Optical potential approach to K{sup +}d scattering at low energies  

SciTech Connect

I study K{sup +}d scattering at low energies using optical potential. My optical potential consists of the first- and second-order terms. The total, integrated elastic, and elastic differential cross sections at incident kaon momenta below 800 MeV/c are calculated using my optical potential. I found that my results are consistent with the Faddeev calculation as well as the data and especially that the second-order optical potential is essential for reproducing them at low energies. I also discuss the multiple scattering effects in this process.

Takaki, Takashi [Department of Economics, Management and Information Science, Onomichi University, Hisayamada 1600, 722-0021 Onomichi (Japan)

2010-05-15

120

Energies of Screened Coulomb Potentials.  

ERIC Educational Resources Information Center

This article shows that, by applying the Hellman-Feynman theorem alone to screened Coulomb potentials, the first four coefficients in the energy series in powers of the perturbation parameter can be obtained from the unperturbed Coulomb system. (Author/HM)

Lai, C. S.

1979-01-01

121

The Potential of Biogas Energy  

Microsoft Academic Search

Biogas technology has been known about for a long time, but in recent years the interest in it has significantly increased, especially due to the higher costs and the rapid depletion of fossil fuels as well as their environmental considerations. The main objective of the present study is to investigate the potential of biogas energy in the 15 European Union

MUSTAFA ACAROGLU; GUNNUR KOCAR; ARIF HEPBASLI

2005-01-01

122

Analysis of Potential Energy Surfaces.  

ERIC Educational Resources Information Center

Introduces different methodological strategies in analyzing potential energy surfaces (PES) used in chemical reactivity studies. Discusses the theory of PES and gives examples to be used for student work. Provides procedures for calculating normal coordinates and vibrational properties of an activated complex. (ML)

Fernandez, G. M.; And Others

1988-01-01

123

Complex angular momentum analysis of low-energy electron elastic scattering from lanthanide atoms  

SciTech Connect

Electron attachment to the lanthanide and Hf atoms resulting in the formation of stable excited lanthanide and Hf anions as Regge resonances is explored in the near-threshold electron impact energy region, E<1.0 eV. The investigation uses the recent Regge-pole methodology wherein is embedded the electron-electron correlations together with a Thomas-Fermi-type model potential incorporating the crucial core-polarization interaction. The near-threshold electron elastic total cross sections (TCSs) for the lanthanide and Hf atoms are found to be characterized by extremely narrow resonances whose energy positions are identified with the binding energies (BEs) of the resultant anions formed during the collision as Regge resonances. The extracted BEs for excited lanthanide anions are contrasted with those of the most recently calculated electron affinities (ground state BEs). We conclude that the BEs for the Pr{sup -}, Tb{sup -}, Dy{sup -}, Ho{sup -}, Er{sup -}, and Tm{sup -} anions of O'Malley and Beck [Phys. Rev. A 79, 012511 (2009)] are not identifiable with the electron affinities as claimed. Formation of bound excited anions is identified in the elastic TCSs of all the lanthanide atoms including Hf, except Eu and Gd. The imaginary part of the complex angular momentum L, ImL is used to distinguish between the shape resonances and the bound excited negative ions. These results challenge both experimentalists and theoreticians alike since the excited anions are very weakly bound, but mostly tenuously bound (BEs<0.1 eV). Shape resonances and Ramsauer-Townsend minima are also presented.

Felfli, Z.; Msezane, A. Z. [Department of Physics and Centre for Theoretical Studies of Physical Systems, Clark Atlanta University, Atlanta, Georgia 30314 (United States); Sokolovski, D. [School of Mathematics and Physics, Queen's University of Belfast, Belfast, BT7 1NN (United Kingdom); Department of Chemical Physics, University of the Basque Country, Leioa (Spain)

2010-04-15

124

On the theory of elastic scattering of slow particles at a 2D potential  

SciTech Connect

A theory is proposed for scattering of particles with a low energy E at an arbitrary 2D potential. This problem is solved using the expansion in the system of zero-energy eigenfunctions. Explicit expressions are obtained for the s-scattering amplitude and for the energy levels of weakly coupled s states. The general formulas derived here are illustrated with an exactly solvable example.

Balagurov, B. Ya., E-mail: balagurov@deom.chph.ras.ru [Russian Academy of Sciences, Emanuel Institute of Biochemical Physics (Russian Federation)

2012-06-15

125

Theoretical modeling for neutron elastic scattering angular distribution in the fast energy range  

SciTech Connect

One of the major issues of neutron scattering modeling in the fast energy range is the contribution of compound elastic and inelastic scattering to the total scattering process. The compound component may become large at very low energies where the angular distribution becomes 90-degree symmetric in the center-of-mass system. Together with the shape elastic component, the elastic scattering gives slightly forward-peaked angular distributions in the fast energy range. This anisotropic angular distribution gives high sensitivities to many important nuclear reactor characteristics, such as criticality and neutron shielding. In this talk we describe how the anisotropic angular distributions are calculated within the statistical model framework, including the case where strongly coupled channels exist, by combining the coupled-channels theory with the Hauser-Feshbach model. This unique capability extension will have significant advantages in understanding the neutron scattering process for deformed nuclei, like uranium or plutonium, on which advanced nuclear energy applications center.

Kawano, Toshihiko [Los Alamos National Laboratory

2010-12-07

126

Microscopic K{sup +}-nucleus optical potential and calculations of differential elastic-scattering cross sections and total reaction cross sections  

SciTech Connect

The differential elastic-scattering cross sections and the total reaction cross sections for the interaction of K{sup +} mesons with {sup 12}C and {sup 40}Ca nuclei at beam momenta of 0.635, 0.715, and 0.8 GeV/c are calculated. The microscopic optical potential derived in the high-energy approximation is used in these calculations. It is determined by the amplitude for kaon-nucleon scattering and the density distribution of pointlike nucleons of the target nucleus. In the high-energy approximation, the Klein-Gordon-Fock equation reduces to the form of the Schroedinger equation. It is shown that small distinctions between the reduction methods do not lead to significant changes in differential elastic-scattering cross sections, but the effects of relativization as such are quite large. Good agreement with experimental data on elastic K{sup +}A scattering is attained. The total reaction cross sections can be described upon adding, to the volume potential, a term that takes the form of its derivative and which has a maximum at the periphery, its contribution being fitted to experimental data.

Lukyanov, V. K., E-mail: lukyanov@theor.jinr.ru; Zemlyanaya, E. V.; Lukyanov, K. V. [Joint Institute for Nuclear Research (Russian Federation); Hanna, K. M. [NRC, Atomic Energy Authority, Department of Mathematical and Theoretical Physics (Egypt)

2010-08-15

127

California Industrial Energy Efficiency Potential  

SciTech Connect

This paper presents an overview of the modeling approach andhighlights key findings of a California industrial energy efficiencypotential study. In addition to providing estimates of technical andeconomic potential, the study examines achievable program potential undervarious program-funding scenarios. The focus is on electricity andnatural gas savings for manufacturing in the service territories ofCalifornia's investor-owned utilities (IOUs). The assessment is conductedby industry type and by end use. Both crosscutting technologies andindustry-specific process measures are examined. Measure penetration intothe marketplace is modeled as a function of customer awareness, measurecost effectiveness, and perceived market barriers. Data for the studycomes from a variety of sources, including: utility billing records, theEnergy Information Association (EIA) Manufacturing Energy ConsumptionSurvey (MECS), state-sponsored avoided cost studies, energy efficiencyprogram filings, and technology savings and cost data developed throughLawrence Berkeley National Laboratory (LBNL). The study identifies 1,706GWh and 47 Mth (million therms) per year of achievable potential over thenext twelve years under recent levels of program expenditures, accountingfor 5.2 percent of industrial electricity consumption and 1.3 percent ofindustrial natural gas consumption. These estimates grow to 2,748 GWh and192 Mth per year if all cost-effective and achievable opportunities arepursued. Key industrial electricity end uses, in terms of energy savingspotential, include compressed air and pumping systems that combine toaccount for about half of the total achievable potential estimates. Fornatural gas, savings are concentrated in the boiler and process heatingend uses, accounting for over 99 percent to total achievablepotential.

Coito, Fred; Worrell, Ernst; Price, Lynn; Masanet, Eric; RafaelFriedmann; Rufo, Mike

2005-06-01

128

Effect of covalency, zero-point energy and charge transfer on the phase-transition, elastic and thermophysical properties of Ca-chalcogenides under compression  

Microsoft Academic Search

The pressure induced phase-transition, elastic and thermophysical properties of Ca-chalcogenides have been investigated by means of many body potential. The modified charge transfer potential consists of long-range Coulomb and charge-transfer interactions modified by covalency and short-range overlap repulsion extended up to second neighbours and zero-point energy effects. Another charge-transfer model excludes covalency and zero-point energy effects. These chalcogenides undergo first-order

D. C. Gupta; K. C. Singh

2010-01-01

129

Spectral Modeling of Residual Stress and Stored Elastic Strain Energy in Thermal Barrier Coatings  

SciTech Connect

Solutions to the thermoelastic problem are important for characterizing the response under temperature change of refractory systems. This work extends a spectral fast Fourier transform (FFT) technique to analyze the thermoelastic behavior of thermal barrier coatings (TBCs), with the intent of probing the local origins of failure in TBCs. The thermoelastic FFT (teFFT) approach allows for the characterization of local thermal residual stress and strain fields, which constitute the origins of failure in TBC systems. A technique based on statistical extreme value theory known as peaks-over-threshold (POT) is developed to quantify the extreme values ("hot spots") of stored elastic strain energy (i.e., elastic energy density, or EED). The resolution dependence of the teFFT method is assessed through a sensitivity study of the extreme values in EED. The sensitivity study is performed both for the local (point-by-point) #12;eld distributions as well as the grain scale #12;eld distributions. A convergence behavior to a particular distribution shape is demonstrated for the local #12;elds. The grain scale fields are shown to exhibit a possible convergence to a maximum level of EED. To apply the teFFT method to TBC systems, 3D synthetic microstructures are created to approximate actual TBC microstructures. The morphology of the grains in each constituent layer as well as the texture is controlled. A variety of TBC materials, including industry standard materials and potential future materials, are analyzed using the teFFT. The resulting hot spots are quantified using the POT approach. A correlation between hot spots in EED and interface rumpling between constituent layers is demonstrated, particularly for the interface between the bond coat (BC) and the thermally grown oxide (TGO) layer.

Donegan, Sean; Rolett, Anthony

2013-12-31

130

Elastic modulus correction term in creep activation energies: applied to oxide dispersion strengthened superalloy  

Microsoft Academic Search

Creep properties of Inconel alloy MA 753 were studied. It was found ; that below 1500°F, where elastic modulus is weakly dependent upon ; temperature, the modulus correction term to creep activation energy is small. ; Accordingly, for superalloy systems such as INCONEL alloy MA 753 and Mar-M 200, ; which show high apparent creep activation energies at this temperature,

M. Malu; J. K. Tien

1975-01-01

131

Systematic study of the nuclear potential through high precision back-angle quasi-elastic scattering measurements of {sup 16}O and {sup 32}S on various targets  

SciTech Connect

Elastic and inelastic scattering have proven an excellent method to probe the nuclear potential in the surface region [1]. A surface diffuseness parameter of around 0.63 fm is accepted as describing elastic and inelastic scattering data. A new method to determine the diffuseness was proposed [2] using high precision quasi-elastic excitation functions at sub-barrier energies, and at backward angles. In response to this proposal, we have made measurements for {sup 32}S+{sup 170}Er, {sup 186}W, {sup 197}Au, {sup 208}Pb[3], and more recently for the reactions {sup 16}O+{sup 144,154}Sm, {sup 186}W, {sup 197}Au, {sup 208}Pb[4].Both single channel and coupled-channels calculations have been performed to extract the diffuseness parameter of the nuclear potential, assuming a Woods-Saxon shape. For the reactions involving near-spherical targets, both theoretical analyses give the same diffuseness parameter, as had been hoped, showing that the effect of couplings to intrinsic excited states in the target and projectile is negligible. On the other hand, for deformed systems, coupling effects are surprisingly important even at deep sub-barrier energies, reducing the flux at backward angles.Energy spectra recorded with the back-angle Si detector show a large number of distinct peaks as well as a broad structure at even higher excitation energies. A comparison of the back-scattered energy spectra with coupled-channels calculations demonstrates that including couplings only to low lying collective states in coupled-channels calculations is inadequate in describing the reaction mechanism even at energies close to the barrier.

Evers, M.; Dasgupta, M.; Hinde, D. J.; Gasques, L. R. [Department of Nuclear Physics, Research School of Physical Sciences and Engineering, Australian National University, Canberra, ACT0200 (Australia)

2009-03-04

132

Salinity effects on water potential components and bulk elastic modulus of Alternanthera philoxeroides (Mart. ) Griseb  

SciTech Connect

Pressure volume curves for Alternanthera philoxeroides (Mart.) Grixeb. (alligator weed) grown in 0 to 400 millimolar NaCl were used to determine water potential (PSI), osmotic potential (psi/sub s/), turgor potential (psi/sub p/) and the bulk elastic modulus (element of) of shoots at different tissue water contents. Values of psi decreased with increasing salinity and tissue PSI was always lower than rhizosphere PSI. The relationship between psi/sub p/ and tissue water content changed because element of increased with salinity. As a results, salt-stressed plants had larger ranges of positive turgor but smaller ranges of tissue water content over which psi/sub p/ was positive. To our knowledge, this is the first report of such a salinity effect on element of in higher plants. These increases in element of with salinity provided a mechanism by which a large difference between plant PSI and rhizosphere PSI, the driving force for water uptake, could be produced with relatively little water loss by the plant. A time-course study of response after salinization to 400 millimolar NaCl showed PSI was constant with 1 day, psi/sub s/ and psi/sub p/ continued to change for 2 to 4 days, and element of continued to change for 4 to 12 days. Changes in element of modified the capacity of alligator weed to maintain a positive water balance and consideration of such changes in other species of higher plants should improve our understanding of salt stress. 24 references, 6 figures.

Bolanos, J.A.; Longstreth, D.J.

1984-06-01

133

Structural, vibrational, and elastic properties of a calcium aluminosilicate glass from molecular dynamics simulations: The role of the potential.  

PubMed

We study a calcium aluminosilicate glass of composition (SiO2)0.60(Al2O3)0.10(CaO)0.30 by means of molecular dynamics. To this end, we conduct parallel simulations, following a consistent methodology, but using three different potentials. Structural and elastic properties are analyzed and compared to available experimental data. This allows assessing the respective abilities of the potentials to produce a realistic glass. We report that, although all these potentials offer a reasonable glass structure, featuring tricluster oxygen atoms, their respective vibrational and elastic predictions differ. This allows us to draw some general conclusions about the crucial role, or otherwise, of the interaction potential in silicate systems. PMID:25028027

Bauchy, M

2014-07-14

134

Nonlinear Elastic Effects on the Energy Flux Deviation of Ultrasonic Waves in GR/EP Composites  

NASA Technical Reports Server (NTRS)

In isotropic materials, the direction of the energy flux (energy per unit time per unit area) of an ultrasonic plane wave is always along the same direction as the normal to the wave front. In anisotropic materials, however, this is true only along symmetry directions. Along other directions, the energy flux of the wave deviates from the intended direction of propagation. This phenomenon is known as energy flux deviation and is illustrated. The direction of the energy flux is dependent on the elastic coefficients of the material. This effect has been demonstrated in many anisotropic crystalline materials. In transparent quartz crystals, Schlieren photographs have been obtained which allow visualization of the ultrasonic waves and the energy flux deviation. The energy flux deviation in graphite/epoxy (gr/ep) composite materials can be quite large because of their high anisotropy. The flux deviation angle has been calculated for unidirectional gr/ep composites as a function of both fiber orientation and fiber volume content. Experimental measurements have also been made in unidirectional composites. It has been further demonstrated that changes in composite materials which alter the elastic properties such as moisture absorption by the matrix or fiber degradation, can be detected nondestructively by measurements of the energy flux shift. In this research, the effects of nonlinear elasticity on energy flux deviation in unidirectional gr/ep composites were studied. Because of elastic nonlinearity, the angle of the energy flux deviation was shown to be a function of applied stress. This shift in flux deviation was modeled using acoustoelastic theory and the previously measured second and third order elastic stiffness coefficients for T300/5208 gr/ep. Two conditions of applied uniaxial stress were considered. In the first case, the direction of applied uniaxial stress was along the fiber axis (x3) while in the second case it was perpendicular to the fiber axis along the laminate stacking direction (x1).

Prosser, William H.; Kriz, R. D.; Fitting, Dale W.

1992-01-01

135

Microscopic description of Li7 in Li7 + C12 and Li7 + Si28 elastic scattering at high energies  

NASA Astrophysics Data System (ADS)

We employ a microscopic continuum-discretized coupled-channels reaction framework (MCDCC) to study the elastic angular distribution of the 7Li=?+t nucleus colliding with C12 and Si28 targets at ELab=350 MeV. In this framework, the Li7 projectile is described in a microscopic cluster model and impinges on noncomposite targets. The diagonal and coupling potentials are constructed from nucleon-target interactions and Li7 microscopic wave functions. We obtain a fair description of the experimental data, in the whole angular range studied, when continuum channels are included. The inelastic and breakup angular distributions on the lightest target are also investigated. In addition, we compute 7Li+12C MCDCC elastic cross sections at energies much higher than the Coulomb barrier and we use them as reference calculations to test the validity of multichannel eikonal cross sections.

Pinilla, E. C.; Descouvemont, P.

2014-05-01

136

Interatomic potentials for CaCO 3 polymorphs (calcite and aragonite), fitted to elastic and vibrational data  

Microsoft Academic Search

Calcite and aragonite have been modeled using rigid-ion, two-body Born-type potentials, supplemented by O-C-O angular terms inside the CO3 groups. A shell model has also been developed for calcite. Atomic charges, repulsive parameters and force constants have been optimized to reproduce the equilibrium crystal structures, the elastic constants and the Raman and infrared vibrational frequencies. The rigid-ion potential RIM (atomic

A. Pavese; M. Catti; G. D. Price; R. A. Jackson

1992-01-01

137

Interatomic potentials for CaCO3 polymorphs (calcite and aragonite), fitted to elastic and vibrational data  

Microsoft Academic Search

Calcite and aragonite have been modeled using rigid-ion, two-body Born-type potentials, supplemented by O-C-O angular terms inside the CO3 groups. A shell model has also been developed for calcite. Atomic charges, repulsive parameters and force constants have been optimized to reproduce the equilibrium crystal structures, the elastic constants and the Raman and infrared vibrational frequencies. The rigid-ion potential RIM (atomic

A. Pavese; M. Catti; G. D. Price; R. A. Jackson

1992-01-01

138

Analysis of pp and bar pp Elastic Scattering Based on High Energy Bounds  

NASA Astrophysics Data System (ADS)

Considering the Froissart-Martin bound, Jin-Martin-Cornille bound and the optical theorem, we propose a novel parametrization for the total cross-section of proton-proton and antiproton-proton elastic scattering data. Using derivative dispersion relations we obtain the real part of the elastic scattering amplitude and thus the ? parameter. Simultaneous fits to ?tot and ? are performed allowing very good statistical descriptions of the available data. Furthermore, predictions to ?tot and ? at energies not used in the fit procedures are presented. For ?tot we obtain predictions at RHIC, LHC and future hadron collider energies.

Campos, S. D.; Okorokov, V. A.

139

Energy functions for rubber from microscopic potentials  

Microsoft Academic Search

The finite deformation theory of rubber and related materials is based on energy functions that describe the macroscopic response of these materials under deformation. Energy functions and elastic constants are here derived from a simple microscopic (ball-and-spring) model. Exact uniaxial force-extension relationships are given for Hooke’s Law and for the thermodynamic entropy-based microscopic model using the Gaussian and the inverse

A. S. Johal; D. J. Dunstan

2007-01-01

140

Energy functions for rubber from microscopic potentials  

Microsoft Academic Search

The finite deformation theory of rubber and related materials is based on energy functions that describe the macroscopic response of these materials under deformation. Energy functions and elastic constants are here derived from a simple microscopic (ball-and-spring) model. Exact uniaxial force-extension relationships are given for Hooke's Law and for the thermodynamic entropy-based microscopic model using the Gaussian and the inverse

A. S. Johal; D. J. Dunstan

2007-01-01

141

Energy current imaging method for time reversal in elastic media  

SciTech Connect

An energy current imaging method is presented for use in locating sources of wave energy during the back propagation stage of the time reversal process. During the back propagation phase of an ideal time reversal experiment, wave energy coalesces from all angles of incidence to recreate the source event; after the recreation, wave energy diverges in every direction. An energy current imaging method based on this convergence/divergence behavior has been developed. The energy current imaging method yields a smaller spatial distribution for source reconstruction than is possible with traditional energy imaging methods.

Anderson, Brian E [Los Alamos National Laboratory; Ulrich, Timothy J [Los Alamos National Laboratory; Le Bas, Pierre - Yves A [Los Alamos National Laboratory; Larmat, Carene [Los Alamos National Laboratory; Johnson, Paul A [Los Alamos National Laboratory; Guyer, Robert A [UNR; Griffa, Michele [ETH ZURICH

2009-01-01

142

REFLECTION AND TRANSMISSION OF THE ENERGY OF HARMONIC ELASTIC WAVES IN A BENT BAR  

Microsoft Academic Search

Harmonic elastic waves in a uniform bar with a semi-infinite straight input section, a bend with constant radius of curvature, and a semi-infinite straight output section are considered, with the effects of rotary inertia and shear deformation being neglected. For a given incident extensional or flexural wave, the relative energy fluxes of the reflected and transmitted waves of both kinds

C. M. Wu; B. Lundberg

1996-01-01

143

Exploiting elastic energy storage for cyclic manipulation: Modeling, stability, and observations for dribbling  

Microsoft Academic Search

For creating robots that are capable of human like performance in terms of speed, energetic properties, and robustness, intrinsic compliance is a promising design element. In this paper we investigate the effects of elastic energy storage and release for ball dribbling in terms of cycle stability. We base the analysis on error evolution, peak power performance during hand contact, and

Sami Haddadin; Kai Krieger; Alin Albu-Schaffer

2011-01-01

144

A STUDY OF STORAGE AND UTILIZATION OF ELASTIC ENERGY IN HUMAN LOWER LIMB MUSCLES  

Microsoft Academic Search

INTRODUCTION: In order to reveal how load, length of muscles, velocity of stretch and other factors affect the storage and the utilization of the elastic energy, lower limb muscular eccentric contraction in take-off phase of jumping were studied. In the past, Many studies about this topic was based on muscles in vitro, but this paper was based on muscles in

Yuqin Shi; Fuming Gu

145

Energy dependence of non-Rutherford proton elastic scattering spectrum for hafnium nitride thin film  

NASA Astrophysics Data System (ADS)

The energy dependence of the backscattering spectrum of non-Rutherford proton elastic scattering spectrum for a hafnium nitride (HfN) thin film was investigated. The purpose of the study is to demonstrate the feasibility of proton elastic scattering at 1.6 MeV as a tool for compositional analysis of transition metal nitride films on a silicon substrate. A HfN thin film deposited on a silicon substrate was analyzed by a common Rutherford backscattering spectrometry (RBS) with an ? beam at the energy of 1.98 MeV, and also by a proton elastic scattering at the energies between 1.53 MeV and 1.61 MeV. The results of two measurements were compared, and a good agreement for nitrogen composition was obtained when the proton energy was higher than 1.59 MeV. It was found that non-Rutherford proton elastic scattering can be used for the compositional analysis of HfN thin films with the thickness up to 230 nm. In analyzing a thicker film, careful observation is necessary.

Gotoh, Yasuhito; Ohue, Wataru; Tsuji, Hiroshi

2013-11-01

146

Study of dp-elastic scattering at energies 650, 750 and 1000 MeV/nucleon  

NASA Astrophysics Data System (ADS)

The results of measurements of dp-elastic scattering at 650, 750 and 1000 MeV/nucleon at Nuclotron JINR are reported. The data have been obtained for angels range of 75-120 deg. in the c.m.s. The results are compared with existing data for corresponding values of energies.

Terekhin, A. A.; Ladygin, V. P.; Piyadin, S. M.; Gurchin, Yu. V.; Resnikov, S. G.; Isupov, A. Yu.; Kurilkin, P. K.; Kurilkin, A. K.; Khrenov, A. N.; Vnukov, I. E.

2013-12-01

147

Relaxation of the elastic strain energy of misfitting inclusions due to diffusion of vacancies  

Microsoft Academic Search

Vacancy diffusion is investigated as a mechanism for relaxation of the elastic strain energy caused by a misfitting inclusion. The kinetics of reduction of the total eigenstrain by the deposition or removal of an atom layer along the interface is derived. The time evolution, as well as an estimate for the characteristic time of the relaxation process, is presented. The

J. Svoboda; E. Gamsjäger; F. D. Fischer

2005-01-01

148

Effect of long range potentials on the elastic cross section for the Li11+Pb208 system  

NASA Astrophysics Data System (ADS)

For the Li11+Pb208 system, we find that the breakup process takes place from the forward angle or far distance region through the interaction distance which is obtained from ratios of elastic scattering cross sections to the Rutherford cross section. It is well known that the behavior of the Li11+Pb208 system is closely related to Coulomb dipole excitation effect. From the first ?2 analysis for the elastic cross section of the Li9+Pb208 system, we obtain the short-range potential of the Li11+Pb208 system by exploiting the optical model calculation for the Coulomb dipole excitation effect. To include the effect of the long-range interaction, we use a dynamic complex polarization potential including the Coulomb dipole potential and a long-range nuclear potential with Woods-Saxon form. Using the second ?2 analysis for the elastic cross section of the Li11+Pb208 system, we obtain the electric dipole transition probabilities B (E1) which becomes 1.42 e2fm2 and 1.41 e2fm2 at Ec .m. = 23.1 MeV and 28.3 MeV, respectively.

So, W. Y.; Kim, K. S.; Cheoun, Myung-Ki

2014-05-01

149

Full potential study of the elastic, electronic, and optical properties of spinels MgIn 2S 4 and CdIn 2S 4 under pressure effect  

NASA Astrophysics Data System (ADS)

The structural, elastic, electronic, and optical properties of cubic spinel MgIn 2S 4 and CdIn 2S 4 compounds have been calculated using a full relativistic version of the full-potential linearized-augmented plane wave with the mixed basis FP/APW+lo method. The exchange and correlation potential is treated by the generalized-gradient approximation (GGA). Moreover, the Engel-Vosko GGA formalism is also applied to optimize the corresponding potential for band structure calculations. The ground state properties, including the lattice constants, the internal parameter, the bulk modulus, and the pressure derivative of the bulk modulus are in reasonable agreement with the available data. Using the total energy-strain technique, we have determined the full set of first-order elastic constants Cij and their pressure dependence, which have not been calculated or measured yet. The shear modulus, Young's modulus, and Poisson's ratio are calculated for polycrystalline XIn 2S 4 aggregates. The Debye temperature is estimated from the average sound velocity. Electronic band structures show a direct band gap (?-?) for MgIn 2S 4 and an indirect band gap (K-?) for CdIn 2S 4. The calculated band gaps with EVGGA show a significant improvement over the GGA. The optical constants, including the dielectric function ?( ?), the refractive index n( ?), the reflectivity R( ?), and the energy loss function L( ?) were calculated for radiation up to 30 eV.

Semari, F.; Khenata, R.; Rabah, M.; Bouhemadou, A.; Bin Omran, S.; Reshak, Ali H.; Rached, D.

2010-12-01

150

Elastic scattering of intermediate-energy electrons from C{sub 60} molecules  

SciTech Connect

Experimental and calculated differential cross sections for elastic scattering of electrons by C{sub 60} molecules at collision energies of 100 to 500 eV are reported. The elastic differential cross sections were measured in a standard crossed-beam apparatus, while the calculations were performed employing the Schwinger multichannel technique at the static-exchange level. Diffraction effects, some due to the overall spherical-cage structure and some to scattering by individual C atoms, are observed in both the measured and calculated cross sections.

Hargreaves, L. R.; Lohmann, B. [ARC Centre for Antimatter-Matter Studies, University of Adelaide, Adelaide, 5005 (Australia); Winstead, C.; McKoy, V. [A. A. Noyes Laboratory for Chemical Physics, California Institute of Technology, Pasadena, California 91125 (United States)

2010-12-15

151

Energy trapping of thickness-shear vibration modes of elastic plates with functionally graded materials.  

PubMed

Energy trapping has important applications in the design of thickness-shear resonators. Considerable efforts have been made for the effective utilization and improvement of energy trapping with variations of plate configurations, such as adding electrodes and contouring. As a new approach in seeking improved energy trapping feature, we analyze thickness-shear vibrations in an elastic plate with functionally graded material (FGM) of in-plane variation of mechanical properties, such as elastic constants and density. A simple and general equation governing the thickness-shear modes is derived from a variational analysis. A plate with piecewise constant material properties is analyzed as an example. It is shown that such a plate can support thickness-shear vibration modes with obvious energy trapping. Bechmann's number for the existence of only one trapped mode also can be determined accordingly. PMID:17375839

Wang, Ji; Yang, Jiashi; Li, Jiangyu

2007-03-01

152

Unified interatomic potential and energy barrier distributions for amorphous oxides  

NASA Astrophysics Data System (ADS)

Amorphous tantala, titania, and hafnia are important oxides for biomedical implants, optics, and gate insulators. Understanding the effects of oxide doping is crucial to optimize performance in these applications. However, no molecular dynamics potentials have been created to date that combine these and other oxides that would allow computational analyses of doping-dependent structural and mechanical properties. We report a novel set of computationally efficient, two-body potentials modeling van der Waals and covalent interactions that reproduce the structural and elastic properties of both pure and doped amorphous oxides. In addition, we demonstrate that the potential accurately produces energy barrier distributions for pure and doped samples. The distributions can be directly compared to experiment and used to calculate physical quantities such as internal friction to understand how doping affects material properties. Future analyses using these potentials will be of great value to determine optimal doping concentrations and material combinations for myriad material science applications.

Trinastic, J. P.; Hamdan, R.; Wu, Y.; Zhang, L.; Cheng, Hai-Ping

2013-10-01

153

Three nucleon force effects in intermediate-energy deuteron analyzing powers for dp elastic scattering  

NASA Astrophysics Data System (ADS)

A complete high precision set of deuteron analyzing powers for elastic deuteron-proton (dp) scattering at 250 MeV/nucleon (MeV/N) has been measured. The new data are presented together with data from previous measurements at 70, 100, 135 and 200 MeV/N. They are compared with the results of three-nucleon (3N) Faddeev calculations based on modern nucleon-nucleon (NN) potentials alone or combined with two models of three nucleon forces (3NFs): the Tucson-Melbourne 99 (TM99) and Urbana IX. At 250 MeV/N large discrepancies between pure NN models and data, which are not resolved by including 3NFs, were found at c.m. backward angles of ?c.m.?120° for almost all the deuteron analyzing powers. These discrepancies are quite similar to those found for the cross section at the same energy. We found small relativistic effects that cannot resolve the discrepancies with the data indicating that other, short-ranged 3NFs are required to obtain a proper description of the data.

Sekiguchi, K.; Okamura, H.; Sakamoto, N.; Suzuki, H.; Dozono, M.; Maeda, Y.; Saito, T.; Sakaguchi, S.; Sakai, H.; Sasano, M.; Shimizu, Y.; Wakasa, T.; Yako, K.; Wita?a, H.; Glöckle, W.; Golak, J.; Kamada, H.; Nogga, A.

2011-06-01

154

Ab Initio Potential Energy Surface for H-H2  

NASA Technical Reports Server (NTRS)

Ab initio calculations employing large basis sets are performed to determine an accurate potential energy surface for H-H2 interactions for a broad range of separation distances. At large distances, the spherically averaged potential determined from the calculated energies agrees well with the corresponding results determined from dispersion coefficients; the van der Waals well depth is predicted to be 75 +/- 3 micro E(h). Large basis sets have also been applied to reexamine the accuracy of theoretical repulsive potential energy surfaces (25-70 kcal/mol above the H-H2 asymptote) at small interatomic separations; the Boothroyd, Keogh, Martin, and Peterson (BKMP) potential energy surface is found to agree with results of the present calculations within the expected uncertainty (+/- 1 kcal/mol) of the fit. Multipolar expansions of the computed H-H2 potential energy surface are reported for four internuclear separation distances (1.2, 1.401, 1.449, and 1.7a(0)) of the hydrogen molecule. The differential elastic scattering cross section calculated from the present results is compared with the measurements from a crossed beam experiment.

Patridge, Harry; Bauschlicher, Charles W., Jr.; Stallcop, James R.; Levin, Eugene

1993-01-01

155

Energy and momentum transfer to a 'fully-clamped' elastic plate in an air-blast  

NASA Astrophysics Data System (ADS)

The momentum transfer by a planar wave impinging upon a rigid, free-standing plate in water, a largely incompressible medium, is well understood [1]. Kambouchev et al. [2] extended the results of Taylor [1] to include the nonlinear effects of compressibility whilst Hutchinson [3] has recently addressed the issues of energy and momentum transfer to a rigid, free-standing plate. In this paper, key conclusions from the aforementioned studies are critically re-examined in the context of a 'fully-clamped' elastic plate. The dynamic response of an elastic plate is represented by an equivalent single-degree-of-freedom (SDOF) system. A numerical method based on a Lagrangian formulation of the Euler equations of compressible flow and conventional shock-capturing techn iques, similar to that employed in [2, 3], were employed to solve numerically the interaction between the air blast wave and elastic plate. Particular emphasis is placed on elucidating the energy and momentum transfer to a 'fully-clamped' elastic plate compared to its rigid, free-standing counterpart, and on whether enhancement in the beneficial effects of FSI as a result of fluid compressibility remains and to what extent.

Yuan, Y.; Tan, P. J.

2013-07-01

156

Comparison of stress and total energy methods for calculation of elastic properties of semiconductors.  

PubMed

We explore the calculation of the elastic properties of zinc-blende and wurtzite semiconductors using two different approaches: one based on stress and the other on total energy as a function of strain. The calculations are carried out within the framework of density functional theory in the local density approximation, with the plane wave-based package VASP. We use AlN as a test system, with some results also shown for selected other materials (C, Si, GaAs and GaN). Differences are found in convergence rate between the two methods, especially in low symmetry cases, where there is a much slower convergence for total energy calculations with respect to the number of plane waves and k points used. The stress method is observed to be more robust than the total energy method with respect to the residual error in the elastic constants calculated for different strain branches in the systems studied. PMID:23211738

Caro, M A; Schulz, S; O'Reilly, E P

2013-01-16

157

Comparison of stress and total energy methods for calculation of elastic properties of semiconductors  

NASA Astrophysics Data System (ADS)

We explore the calculation of the elastic properties of zinc-blende and wurtzite semiconductors using two different approaches: one based on stress and the other on total energy as a function of strain. The calculations are carried out within the framework of density functional theory in the local density approximation, with the plane wave-based package vasp. We use AlN as a test system, with some results also shown for selected other materials (C, Si, GaAs and GaN). Differences are found in convergence rate between the two methods, especially in low symmetry cases, where there is a much slower convergence for total energy calculations with respect to the number of plane waves and k points used. The stress method is observed to be more robust than the total energy method with respect to the residual error in the elastic constants calculated for different strain branches in the systems studied.

Caro, M. A.; Schulz, S.; O'Reilly, E. P.

2013-01-01

158

Interfacial profiles in fluid/liquid systems: a description based on the storing of elastic energy.  

PubMed

An analytical expression for the interfacial energy is found by solving a Poisson equation and assuming a Boltzmann distribution of volume elements forming the fluid/liquid system. Interfacial phenomena are treated as a result of the response of a liquid when it makes contact with other fluid phase, in order to reach thermal and mechanical equilibrium. This model gives a quantitative description of the interface, obtaining values for its molar, force and energy density profiles. Also, our model allows the determination of the proportion of the fluids present in the interfacial zone, the values of interfacial tension and thickness. In the case of water+n-alkanes systems, the tensions are in agreement with the behavior shown by the experimental data. Finally, the values for interfacial thickness predicted from molar density profiles are lower than the range of influence of the elastic energy and elastic field. PMID:21421216

Castellanos-Suárez, Aly J; Toro-Mendoza, Jhoan; García-Sucre, Máximo

2011-06-01

159

California's Biomass and Its Energy Potential.  

National Technical Information Service (NTIS)

The potentials for using California's biomass for energy have been assessed. The study relies on the recent work of Amory Lovins and Lawrence Berkeley Laboratory's (LBL) Distributed Energy System's Project to specify an energy future for Californians. The...

F. B. Lucarelli

1980-01-01

160

Radius exponent in elastic and rigid arterial models optimized by the least energy principle  

PubMed Central

Abstract It was analyzed in normal physiological arteries whether the least energy principle would suffice to account for the radius exponent x. The mammalian arterial system was modeled as two types, the elastic or the rigid, to which Bernoulli's and Hagen?Poiseuille's equations were applied, respectively. We minimized the total energy function E, which was defined as the sum of kinetic, pressure, metabolic and thermal energies, and loss of each per unit time in a single artery transporting viscous incompressible blood. Assuming a scaling exponent ? between the vessel radius (r) and length (l) to be 1.0, x resulted in 2.33 in the elastic model. The rigid model provided a continuously changing x from 2.33 to 3.0, which corresponded to Uylings’ and Murray's theories, respectively, through a function combining Reynolds number with a proportional coefficient of the l ? r relationship. These results were expanded to an asymmetric arterial fractal tree with the blood flow preservation rule. While x in the optimal elastic model accounted for around 2.3 in proximal systemic (r >1 mm) and whole pulmonary arteries (r ?0.004 mm), optimal x in the rigid model explained 2.7 in elastic?muscular (0.1 < r ?1 mm) and 3.0 in peripheral resistive systemic arteries (0.004 ? r ?0.1 mm), in agreement with data obtained from angiographic, cast?morphometric, and in vivo experimental studies in the literature. The least energy principle on the total energy basis provides an alternate concept of optimality relating to mammalian arterial fractal dimensions under ? = 1.0.

Nakamura, Yoshihiro; Awa, Shoichi

2014-01-01

161

Radius exponent in elastic and rigid arterial models optimized by the least energy principle.  

PubMed

It was analyzed in normal physiological arteries whether the least energy principle would suffice to account for the radius exponent x. The mammalian arterial system was modeled as two types, the elastic or the rigid, to which Bernoulli's and Hagen-Poiseuille's equations were applied, respectively. We minimized the total energy function E, which was defined as the sum of kinetic, pressure, metabolic and thermal energies, and loss of each per unit time in a single artery transporting viscous incompressible blood. Assuming a scaling exponent ? between the vessel radius (r) and length (l) to be 1.0, x resulted in 2.33 in the elastic model. The rigid model provided a continuously changing x from 2.33 to 3.0, which corresponded to Uylings' and Murray's theories, respectively, through a function combining Reynolds number with a proportional coefficient of the l - r relationship. These results were expanded to an asymmetric arterial fractal tree with the blood flow preservation rule. While x in the optimal elastic model accounted for around 2.3 in proximal systemic (r >1 mm) and whole pulmonary arteries (r ?0.004 mm), optimal x in the rigid model explained 2.7 in elastic-muscular (0.1 < r ?1 mm) and 3.0 in peripheral resistive systemic arteries (0.004 ? r ?0.1 mm), in agreement with data obtained from angiographic, cast-morphometric, and in vivo experimental studies in the literature. The least energy principle on the total energy basis provides an alternate concept of optimality relating to mammalian arterial fractal dimensions under ? = 1.0. PMID:24744905

Nakamura, Yoshihiro; Awa, Shoichi

2014-02-01

162

Geothermal Energy: Tapping the Potential  

ERIC Educational Resources Information Center

Ground source geothermal energy enables one to tap into the earth's stored renewable energy for heating and cooling facilities. Proper application of ground-source geothermal technology can have a dramatic impact on the efficiency and financial performance of building energy utilization (30%+). At the same time, using this alternative energy…

Johnson, Bill

2008-01-01

163

Biowaste energy potential in Kenya  

Microsoft Academic Search

Energy affects all aspects of national development. Hence the current global energy crisis demands greater attention to new initiatives on alternative energy sources that are renewable, economically feasible and sustainable. The agriculture-dependent developing countries in Africa can mitigate the energy crisis through innovative use of the available but underutilised biowaste such as organic residues from maize, barley, cotton, tea and

Charles Nzila; Jo Dewulf; Henri Spanjers; Henry Kiriamiti; Herman van Langenhove

2010-01-01

164

Elastic resistance change and action potential generation of non-faradaic Pt/TiO2/Pt capacitors  

NASA Astrophysics Data System (ADS)

Electric current in the mixed ionic-electronic conductor TiO2 is hysteretic, i.e. history-dependent, and its use is versatile in electronic devices. Nowadays, biologically inspired, analogue-type computing systems, known as neuromorphic systems, are being actively investigated owing to their new and intriguing physical concepts. The realization of artificial synapses is important for constructing neuromorphic systems. In mammalians' brains, the plasticity of synapses between neighbouring nerve cells arises from action potential firing. Emulating action potential firing via inorganic systems has therefore become important in neuromorphic engineering. In this work, the current-voltage hysteresis of TiO2-based non-faradaic capacitors is investigated to primarily focus on the correlation between the blocking contact and the elasticity, i.e. non-plasticity, of the capacitors' resistance change, in experimental and theoretical methods. The similarity between the action potential firing behaviour in nerve cells and the elasticity of the non-faradaic capacitors is addressed.Electric current in the mixed ionic-electronic conductor TiO2 is hysteretic, i.e. history-dependent, and its use is versatile in electronic devices. Nowadays, biologically inspired, analogue-type computing systems, known as neuromorphic systems, are being actively investigated owing to their new and intriguing physical concepts. The realization of artificial synapses is important for constructing neuromorphic systems. In mammalians' brains, the plasticity of synapses between neighbouring nerve cells arises from action potential firing. Emulating action potential firing via inorganic systems has therefore become important in neuromorphic engineering. In this work, the current-voltage hysteresis of TiO2-based non-faradaic capacitors is investigated to primarily focus on the correlation between the blocking contact and the elasticity, i.e. non-plasticity, of the capacitors' resistance change, in experimental and theoretical methods. The similarity between the action potential firing behaviour in nerve cells and the elasticity of the non-faradaic capacitors is addressed. Electronic supplementary information (ESI) available. See DOI: 10.1039/c3nr02154h

Lim, Hyungkwang; Jang, Ho Won; Lee, Doh-Kwon; Kim, Inho; Hwang, Cheol Seong; Jeong, Doo Seok

2013-06-01

165

General solution for transversely isotropic magneto-electro-thermo-elasticity and the potential theory method  

Microsoft Academic Search

The three-dimensional equations of transversely isotropic magneto-electro-thermo-elasticity are simplified by the introduction of two displacement functions. A general solution is then rigorously derived by virtue of the operator theory, which is expressed in terms of two functions, satisfying a second-order and a tenth-order homogeneous partial differential equation, respectively. Utilizing the generalized Almansi's theorem, the general solution can be further simplified

W. Q Chen; Kang Yong Lee; H. J Ding

2004-01-01

166

An energy absorbing far-field boundary condition for the elastic wave equation  

SciTech Connect

The authors present an energy absorbing non-reflecting boundary condition of Clayton-Engquist type for the elastic wave equation together with a discretization which is stable for any ratio of compressional to shear wave speed. They prove stability for a second order accurate finite-difference discretization of the elastic wave equation in three space dimensions together with a discretization of the proposed non-reflecting boundary condition. The stability proof is based on a discrete energy estimate and is valid for heterogeneous materials. The proof includes all six boundaries of the computational domain where special discretizations are needed at the edges and corners. The stability proof holds also when a free surface boundary condition is imposed on some sides of the computational domain.

Petersson, N A; Sjogreen, B

2008-07-15

167

Monte Carlo simulation of ferroelectric domain structure: Electrostatic and elastic strain energy contributions  

SciTech Connect

A lattice-Monte Carlo approach was developed to simulate ferroelectric domain behavior. The model utilizes a Hamiltonian for the total energy that includes electrostatic terms (involving dipole-dipole interactions, local polarization gradients, and applied electric field), and elastic strain energy. The contributions of these energy components to the domain structure and to the overall applied field response of the system were examined. In general, the model exhibited domain structure characteristics consistent with those observed in a tetragonally distorted ferroelectric. Good qualitative agreement between the appearance of simulated electrical hysteresis loops and those characteristic of real ferroelectric materials was found.

POTTER JR.,BARRETT G.; TUTTLE,BRUCE A.; TIKARE,VEENA

2000-04-04

168

Methods to compute dislocation line tension energy and force in anisotropic elasticity  

NASA Astrophysics Data System (ADS)

A frame indifferent formulation of the energy and force on a dislocation in a line tension model in an anisotropic elasticity media is presented. This formulation is valid for any dislocation line direction and Burgers' vector and expresses the energy and force in terms of an integral for which no general analytical solution can be calculated. Three numerical methods are investigated to evaluate the energy and the force: direct numerical integration, spherical harmonics expansions and an interpolation table method. We analyze the convergence and computational cost of each method and compare them with a view to selecting the most appropriate for implementation in large scale dislocation dynamics codes.

Aubry, S.; Fitzgerald, S. P.; Arsenlis, A.

2014-01-01

169

Interatomic potentials for CaCO3 polymorphs (calcite and aragonite), fitted to elastic and vibrational data  

NASA Astrophysics Data System (ADS)

Calcite and aragonite have been modeled using rigid-ion, two-body Born-type potentials, supplemented by O-C-O angular terms inside the CO3 groups. A shell model has also been developed for calcite. Atomic charges, repulsive parameters and force constants have been optimized to reproduce the equilibrium crystal structures, the elastic constants and the Raman and infrared vibrational frequencies. The rigid-ion potential RIM (atomic charges: z O= -0.995 e, z C = 0.985 e, z Ca = 2.0 e) fitted to calcite properties is able to account for those of aragonite as well. Experimental unit-cell edges, elastic constants, internal and lattice frequencies are reproduced with average relative errors of 2.1, 5.5, 2.4, 15.1% for calcite and of 0.2, 19.4, 2.5, 11.8% for aragonite, respectively. The RIM potential is suitable for thermodynamic and phase diagram simulations in the CaCO3 system, and is discussed and compared to other potentials.

Pavese, A.; Catti, M.; Price, G. D.; Jackson, R. A.

1992-08-01

170

SH Surface Waves in a Homogeneous Gradient-Elastic Half-Space with Surface Energy  

Microsoft Academic Search

The existence of SH surface waves in a half-space of homogeneous material (i.e. anti-plane shear wave motions which decay exponentially with the distance from the free surface) is shown to be possible within the framework of the generalized linear continuum theory of gradient elasticity with surface energy. As is well-known such waves cannot be predicted by the classical theory of

I. VARDOULAKIS; H. G. GEORGIADIS

1997-01-01

171

EMTA’s Evaluation of the Elastic Properties for Fiber Polymer Composites Potentially Used in Hydropower Systems  

SciTech Connect

Fiber-reinforced polymer composites can offer important advantages over metals where lightweight, cost-effective manufacturing and high mechanical performance can be achieved. To date, these materials have not been used in hydropower systems. In view of the possibility to tailor their mechanical properties to specific applications, they now have become a subject of research for potential use in hydropower systems. The first step in any structural design that uses composite materials consists of evaluating the basic composite mechanical properties as a function of the as-formed composite microstructure. These basic properties are the elastic stiffness, stress-strain response, and strength. This report describes the evaluation of the elastic stiffness for a series of common discontinuous fiber polymer composites processed by injection molding and compression molding in order to preliminarily estimate whether these composites could be used in hydropower systems for load-carrying components such as turbine blades. To this end, the EMTA (Copyright © Battelle 2010) predictive modeling tool developed at the Pacific Northwest National Laboratory (PNNL) has been applied to predict the elastic properties of these composites as a function of three key microstructural parameters: fiber volume fraction, fiber orientation distribution, and fiber length distribution. These parameters strongly control the composite mechanical performance and can be tailored to achieve property enhancement. EMTA uses the standard and enhanced Mori-Tanaka type models combined with the Eshelby equivalent inclusion method to predict the thermoelastic properties of the composite based on its microstructure.

Nguyen, Ba Nghiep; Paquette, Joshua

2010-08-01

172

Repulsive nature of optical potentials for high-energy heavy-ion scattering  

NASA Astrophysics Data System (ADS)

The recent works by the present authors predicted that the real part of heavy-ion optical potentials changes its character from attraction to repulsion around the incident energy per nucleon E/A=200-300MeV on the basis of the complex G-matrix interaction and the double-folding model (DFM) and revealed that the three-body force plays an important role there. In the present paper, we have precisely analyzed the energy dependence of the calculated DFM potentials and its relation to the elastic-scattering angular distributions in detail in the case of the C12+C12 system in the energy range of E/A=100-400MeV. The tensor force contributes substantially to the energy dependence of the real part of the DFM potentials and plays an important role to lower the attractive-to-repulsive transition energy. The nearside and farside (N/F) decompositions of the elastic-scattering amplitudes clarify the close relation between the attractive-to-repulsive transition of the potentials and the characteristic evolution of the calculated angular distributions with the increase of the incident energy. Based on the present analysis, we propose experimental measurements for the predicted strong diffraction phenomena of the elastic-scattering angular distribution caused by the N/F interference around the attractive-to-repulsive transition energy together with the reduced diffractions below and above the transition energy.

Furumoto, T.; Sakuragi, Y.; Yamamoto, Y.

2010-10-01

173

Elastic resistance change and action potential generation of non-faradaic Pt/TiO2/Pt capacitors.  

PubMed

Electric current in the mixed ionic-electronic conductor TiO2 is hysteretic, i.e. history-dependent, and its use is versatile in electronic devices. Nowadays, biologically inspired, analogue-type computing systems, known as neuromorphic systems, are being actively investigated owing to their new and intriguing physical concepts. The realization of artificial synapses is important for constructing neuromorphic systems. In mammalians' brains, the plasticity of synapses between neighbouring nerve cells arises from action potential firing. Emulating action potential firing via inorganic systems has therefore become important in neuromorphic engineering. In this work, the current-voltage hysteresis of TiO2-based non-faradaic capacitors is investigated to primarily focus on the correlation between the blocking contact and the elasticity, i.e. non-plasticity, of the capacitors' resistance change, in experimental and theoretical methods. The similarity between the action potential firing behaviour in nerve cells and the elasticity of the non-faradaic capacitors is addressed. PMID:23733132

Lim, Hyungkwang; Jang, Ho Won; Lee, Doh-Kwon; Kim, Inho; Hwang, Cheol Seong; Jeong, Doo Seok

2013-07-21

174

Wind energy potential in Palestine  

Microsoft Academic Search

Weibull parameters of the wind speed distribution function were computed for 49 weather stations in Palestine. Wind potentials in kWh\\/m2 yr were calculated at the above stations, then contours of wind potential were drawn. Electricity from the wind can be generated, in some locations in the West Bank, at a cost of 0.07 $\\/kWh.

Afif Hasan

1997-01-01

175

Exam Question Exchange: Potential Energy Surfaces.  

ERIC Educational Resources Information Center

Presents three examination questions, graded in difficulty, that explore the topic of potential energy surfaces using a diagrammatic approach. Provides and discusses acceptable solutions including diagrams. (CW)

Alexander, John J., Ed.

1988-01-01

176

Rainbow structure and g-u-interference effects in the elastic scattering of low energy protons on deuterium and hydrogen atoms  

Microsoft Academic Search

Elastic differential cross sections for the scattering of low energy protons (Ec.m.=11-142 eV) on H and D atoms have been obtained. The curves exhibit clearly rainbow structure, g-u oscillations and a type of rapid interference, if coherent scattering of both sigmag and sigmau potential curves is taken into account. For comparison, partial wave calculations have been performed using WKB phases

A. Ding; J. Karlau; J. Weise

1976-01-01

177

Wind potential energy determination at Cammazes site.  

National Technical Information Service (NTIS)

Wind speed and direction data were measured on the complex topographic site of Cammazes (France). The data were then correlated to the speed and direction data from the meteorological station of Carcassonne. The potential wind energy and the annual energy...

J. P. Flori P. Duchene-Marullaz

1986-01-01

178

Cotton Stalk as a Potential Energy Source  

Microsoft Academic Search

Policymakers have a growing interest in the development of domestic energy sources. One renewable energy source, biomass, is receiving consideration as a potential energy source. Among agricultural biomass materials, crop residue has energy value in direct combustion and gasification as well as in the manufacture of hydrocarbon fuels. The main objective of the present study is to investigate many aspects

R. CENGIZ AKDENIZ; MUSTAFA ACAROGLU; ARIF HEPBASLI

2004-01-01

179

Interacting elastic lattice polymers: A study of the free energy of globular rings  

NASA Astrophysics Data System (ADS)

We introduce and implement a Monte Carlo scheme to study the equilibrium statistics of polymers in the globular phase. It is based on a model of "interacting elastic lattice polymers" and allows a sufficiently good sampling of long and compact configurations, an essential prerequisite to study the scaling behavior of free energies. By simulating interacting self-avoiding rings at several temperatures in the collapsed phase, we estimate both the bulk and the surface free energy. Moreover from the corresponding estimate of the entropic exponent ? -2 we provide evidence that, unlike for swollen and ?-point rings, the hyperscaling relation is not satisfied for globular rings.

Baiesi, M.; Orlandini, E.

2014-06-01

180

Simultaneous optical model analysis of elastic scattering, fusion, and breakup for the {sup 9}Be+{sup 144}Sm system at near-barrier energies  

SciTech Connect

A simultaneous optical model calculation of elastic scattering, complete fusion, and breakup cross sections for energies around the Coulomb barrier is presented for reactions involving the weakly bound projectile {sup 9}Be on the medium size target {sup 144}Sm. In the calculations, the nuclear polarization potential U is split into a volume part U{sub F}, which is responsible for fusion reactions, and a surface part U{sub DR}, which accounts for direct reactions. A simultaneous {chi}{sup 2} analysis of elastic and complete fusion data shows that the extracted optical potential parameters of the real V{sub F} and imaginary W{sub F} parts of U{sub F} and the corresponding parts V{sub DR} and W{sub DR} of U{sub DR} satisfy separately the dispersion relation. Energy-dependent forms for the fusion and direct reaction potentials indicate that, at the strong absorption radius, the direct reaction potentials dominate over the fusion potentials. Moreover, the imaginary direct reaction potential results in a rather smooth function of E around the barrier energy. These findings show that the threshold anomaly, usually present in reactions with tightly bound projectiles, is not exhibited for the system {sup 9}Be+{sup 144}Sm. Within this formalism, the effect of breakup reactions on complete fusion is studied by turning on and off the potentials responsible for breakup reactions.

Gomez Camacho, A.; Gomes, P. R. S.; Lubian, J.; Padron, I. [Departamento del Acelerador, Instituto Nacional de Investigaciones Nucleares, Apartado Postal 18-1027, C. P. 11801, Mexico D. F. Centro (Mexico); Instituto de Fisica, Universidade Federal Fluminenese, Avenida Litoranea s/n, Gragoata, Niteroi, RJ 24210-340 (Brazil); Centro de Aplicaciones Tecnologicas y Desarrollo Nuclear, Playa, Ciudad de la Habana (Cuba)

2008-05-15

181

Nonlinear elastic effects on the energy flux deviation of ultrasonic waves in gr/ep composites  

NASA Technical Reports Server (NTRS)

The effects of nonlinear elasticity on energy flux deviation in undirectional gr/ep composites are examined. The shift in the flux deviation is modeled using acoustoelasticity theory and the second- and third-order elastic stiffness coefficients for T300/5208 gr/ep. Two conditions of applied uniaxial stress are considered. In the first case, the direction of applied uniaxial stress was along the fiber axis (x3), while in the second case it was perpendicular to the fiber axis along the laminate stacking direction (x1). For both conditions, the change in the energy flux deviation angle from the condition of zero applied stress is computed over the range of propagation directions of 0 to 60 deg from the fiber axis at two-degree intervals. A positive flux deviation angle implies the energy deviates away from the fiber direction toward the x1 axis, while a negative deviation means that the energy deviates toward the fibers. Over this range of fiber orientation angles, the energy of the quasi-longitudinal and pure mode transverse waves deviates toward the fibers, while that of the quasi-transverse mode deviates away from the fibers.

Prosser, William H.; Kriz, R. D.; Fitting, Dale W.

1992-01-01

182

Potential Water and Energy Savings from Showerheads  

SciTech Connect

This paper estimates the benefits and costs of six water reduction scenarios. Benefits and costs of showerhead scenarios are ranked in this paper by an estimated water reduction percentage. To prioritize potential water and energy saving scenarios regarding showerheads, six scenarios were analyzed for their potential water and energy savings and the associated dollar savings to the consumer.

Biermayer, Peter J.

2005-09-28

183

Pseudo-potential calculations of structural and elastic properties of spinel oxides ZnX2O4 (X=Al, Ga, In) under pressure effect  

NASA Astrophysics Data System (ADS)

First principle calculations of structural and elastic properties of ZnAl2O4, ZnGa2O4 and ZnIn2O4 compounds are presented, using the pseudo-potential plane-waves approach based on density functional theory, within the generalized gradient approximation GGA. The lattice constants and internal parameters are in good agreement with the available experimental results. Young's modulus, Poisson ratio, bulk modulus, elastic constants and their pressure dependence are also calculated. As the experimental elastic constants are not available hence our results were only compared with the available theoretical values obtained at equilibrium volume.

Bouhemadou, A.; Khenata, R.

2006-12-01

184

Measurement of the elastic, total and diffraction cross sections at tevatron energies  

SciTech Connect

The CDF collaboration has measured the differential elastic cross section d{sigma}{sub el}/dt, the single diffraction dissociation double differential cross section d{sup 2}{sigma}{sub sd}/dM{sup 2}dt and the total inelastic cross section for antiproton-proton collisions at center of mass energies {radical}s = 546 and 1,800 GeV. Data for this measurement have been collected in short dedicated runs during the 1988--1989 data taking period of CDF. The elastic scattering slope is 15.28 {+-} 0.58 (16.98 {+-} 0.25) GeV{sup {minus}2} at {radical}s = 546 (1,800) GeV. Using the luminosity independent method (1 + {rho}{sup 2}){sigma}{sub T} is measured to be 62.64 {+-} 0.95 (81.83 {+-} 2.29) mb at {radical}s = 546 (1,800) GeV. Assuming {rho} = 0.15 the elastic, total and single diffraction cross sections are {sigma}{sub el} = 12.87 {+-} 0.30, {sigma}{sub T} = 61.26 {+-} 0.93 and {sigma}{sub sd} = 7.89 {+-} 0.33 mb ({sigma}{sub el} = 19.70 {+-} 0.85, {sigma}{sub T} = 80.03 {+-} 2.24 and {sigma}{sub sd} = 9.46 {+-} 0.44 mb) at {radical}s = 546 (1,800) GeV.

Belforte, S. [Istituto Nazionale di Fisica Nucleare, Pisa (Italy); CDF Collaboration

1993-11-01

185

Price and income elasticities of energy demand: Some estimates for Kuwait using two econometric models  

SciTech Connect

This paper estimates the demand for energy in Kuwait for the period 1965-1989 using two econometric models: a cointegration and error correction model (ECM) and a simultaneous-equation model (SEM). The results obtained from both models are similar. It is found that the energy demand is inelastic with respect to price in the short and long run, and while it is elastic in the long run, the energy demand is inelastic with respect to income in the short run. Both models` validation shows that the ECM performed better in replicating the past than the simultaneous model, suggesting the need to use the ECM to identify future prospects for energy demand in Kuwait.

Al-Mutairi, N.H.; Eltony, M.N.

1995-12-31

186

Geothermal Energy Potential in Western United States  

ERIC Educational Resources Information Center

Reviews types of geothermal energy sources in the western states, including hot brine systems and dry steam systems. Conversion to electrical energy is a major potential use of geothermal energy, although it creates environmental disruptions such as noise, corrosion, and scaling of equipment. (AV)

Pryde, Philip R.

1977-01-01

187

High-energy asymptotic behavior of the Bourrely-Soffer-Wu model for elastic scattering  

NASA Astrophysics Data System (ADS)

Some time ago, an accurate phenomenological approach, the BSW model, was developed for proton-proton and antiproton-proton elastic scattering cross sections at center-of-mass energies above 10 GeV. This model has been used to give successful theoretical predictions for these processes, at successive collider energies. The BSW model involves a combination of integrals that, while computable numerically at fairly high energies, require some mathematical analysis to reveal the high-energy asymptotic behavior. In this paper we present a high-energy asymptotic representation of the scattering amplitude at moderate momentum transfer, for the leading order in an expansion parameter closely related to the logarithm of the center-of-mass energy. The fact that the expansion parameter goes as the logarithm of the energy means that the asymptotic behavior is accurate only for energies greatly beyond any foreseeable experiment. However, we compare the asymptotic representation against the numerically calculated model for energies in a less extreme region of energy. The asymptotic representation is given by a simple formula which, in particular, exhibits the oscillations of the differential cross section with momentum transfer. We also compare the BSW asymptotic behavior with the Singh-Roy unitarity upper bound for the diffraction peak.

Bourrely, Claude; Myers, John M.; Soffer, Jacques; Wu, Tai Tsun

2012-05-01

188

Complete set of deuteron analyzing powers for dp elastic scattering at intermediate energies  

NASA Astrophysics Data System (ADS)

With the aim of clarifying roles of the 3NFs in nuclei experimental programs with polarized deuterons beams at intermediate energies are in progress at RIKEN RI Beam Factory. As the first step, we have measured a complete set of deuteron analyzing powers ( iT 11, T 20, T 21, T 22) in deuteron-proton elastic scattering at 250 and 294 MeV/nucleon. The obtained data are compared with the Faddeev calculations based on the modern nucleon-nucleon forces together with the Tucson-Melbourne'99, and UrbanaIX three nucleon forces.

Sekiguchi, K.; Okamura, H.; Wada, Y.; Miyazaki, J.; Taguchi, T.; Gebauer, U.; Dozono, M.; Kawase, S.; Kubota, Y.; Lee, C. S.; Maeda, Y.; Mashiko, T.; Miki, K.; Sakaguchi, S.; Sakai, H.; Sakamoto, N.; Sasano, M.; Shimizu, Y.; Takahashi, K.; Tang, R.; Uesaka, T.; Wakasa, T.; Yako, K.

2014-01-01

189

Overlap function analysis of ?WENA elastic and charge exchange scattering at high energies  

Microsoft Academic Search

Summary  In terms of overlap functions, a new kind of analysis of ?\\u000a \\u000a elastic and charge exchange scattering data at high energies and small momentum transfers is given. The data analysed cover\\u000a a range 6 GeV\\/c?q\\u000a \\u000a L\\u000a =pion laboratory momentum ?18 GeV\\/c and 0??t=(centre-of-mass momentum transfer)2 ?1 (GeV\\/c)2. The phenomenological expressions of the scattering amplitudes, including spin-flip, as they are obtained

R. Henzi

1967-01-01

190

Radially symmetric thermo-elastic wave propagation without energy dissipation in an infinitely extended thin plate with a circular hole  

Microsoft Academic Search

In this article a model of the linear thermo-elastic theory without energy dissipation is employed to study radially symmetric thermo-elastic wave propagation in an infinitely extended thin plate with a circular hole when the inner boundary of the hole is subjected to (i) zero stress and a step-input of temperature rise and (ii) a step-input of stress and zero temperature

S. K. Roy Choudhuri; Nupur Bandyopadhyay

2006-01-01

191

On the asymptotic approximation for the elastic scattering by a potential  

Microsoft Academic Search

Summary  — The set of approximations usually known as the « semi-classical description of scattering » is developed in such a way that\\u000a the next orders in the asymptotic expansions may be calculated. An additional approximation enables one to treat the effects\\u000a of surface potentials and, in particular, spin-orbit potentials. In order to avoid nonessential difficulties, the derivation\\u000a is done in

P. C. Sabatier

1965-01-01

192

Potential energy surface of alanine polypeptide chains  

Microsoft Academic Search

The multidimensional potential energy surfaces of the peptide chains consisting of three and six alanine (Ala) residues have\\u000a been studied with respect to the degrees of freedom related to the twist of these molecules relative to the peptide backbone\\u000a (these degrees of freedom are responsible for the folding of such peptide molecules and proteins). The potential energy surfaces\\u000a have been

I. A. Solov’yov; A. V. Yakubovitch; A. V. Solov’yov; W. Greiner

2006-01-01

193

Kinetic energy contributions to heavy ion potentials  

Microsoft Academic Search

It is shown that the change in the intrinsic kinetic energies of two interacting heavy ions gives a repulsive contribution to the heavy ion interaction potential. It is proposed that this effect explains a major part of the discrepancy between folded and experimentally determined HI potentials.

P. G. Zint; U. Mosel

1975-01-01

194

Energy levels in modified quantum statistical potentials  

Microsoft Academic Search

We calculate one-electron energy levels in potentials derived from the solution of the atomic Thomas-Fermi-Dirac equation. A local exchange potential is used. Corrections are made to a previous theory, which joins a TFD density to a quantum mechanical electron density near the nucleus, where the Thomas-Fermi-Dirac density has an incorrect singularity. Use of a potential derived from this theory leads

Jerry Goodisman

1972-01-01

195

Multiple scattering approach to elastic low-energy electron collisions with the water dimer  

NASA Astrophysics Data System (ADS)

Multiple scattering theory is applied to low-energy electron collisions with a complex target formed of two molecular scatterers. The total T-matrix is expressed in terms of the T-matrix for each isolated molecule. We apply the approach to elastic electron-(H2O)2 collisions. Following the method developed in our previous work on crystalline ice (Caron et al 2007 Phys. Rev. A 76 032716), we impose a cut-off on the dipole outside the R-matrix sphere and an energy-dependent cut-off on the angular momentum components of the monomer T-matrix. An R-matrix calculation of electron-dimer collisions is performed in order to evaluate the accuracy of the multiple scattering approach. The agreement between the two calculations is very good.

Bouchiha, D.; Caron, L. G.; Gorfinkiel, J. D.; Sanche, L.

2008-02-01

196

Asymmetries for elastic scattering of ?+/- from polarized 3He at ? resonance energies  

NASA Astrophysics Data System (ADS)

Asymmetries Ay for ?+ and ?- elastic scattering from polarized 3He were measured at incident energies passing through the ? nucleon P33, or ?(1232), resonance. The data were taken at the Clinton P. Anderson Meson Physics Facility using the high-energy pion channel P3 and a large acceptance spectrometer to detect the scattered pions. The polarized 3He target, originally developed at TRIUMF, was modified for these experiments by the addition of diode lasers. Completely unexpected negative asymmetries were observed at and below the resonance in ?+ scattering near 50°-60°, which cannot be reproduced by multiple scattering theory and Faddeev wave functions. A hybrid model, which adds a ?-neutron spin-spin interaction term to the conventional calculations, provides a good description of the ?+ data. For ?- scattering this term predicts a negligible effect on Ay and the data do not show the anomalous Ay seen with ?+.

Espy, M. A.; O'donnell, J. M.; Davis, B.; Dehnhard, D.; Langenbrunner, J. L.; Larson, B.; Palarczyk, M.; Riedel, C. M.; Wick, K.; Blanchard, S.; Burleson, G. R.; Gibbs, W. R.; Lail, B.; Nelson, B.; Park, B. K.; Zhao, Q.; Cummings, W. J.; Delheij, P. P.; Jennings, B. K.; Häusser, O.; Henderson, R.; Thiessen, D.; Brash, E.; Jones, M. K.; Brinkmöller, B.; Maeda, K.; Merrill, F.; Morris, C. L.; Penttilä, S.; Swenson, D.; Tupa, D.; Bennhold, C.; Kamalov, S. S.

1997-11-01

197

Microscopic Neutron Optical Potential in the Energy Region 65-225 MeV  

NASA Astrophysics Data System (ADS)

In the present work, we report a microscopic optical potential analysis of the extensive neutron elastic scattering data from 12C, 40Ca and 208Pb in the 65-225 MeV energy region. Brueckner-Hartree-Fock method has been used to calculate the optical potential, where one requires internucleon potential to calculate reaction matrices which are then folded over the nucleon densities in the target nuclei. We report the predictions of the calculated potential using Argonne v-18 and Urbana v-14 local nucleon-nucleon potentials. The modern potential v-18 has been used for the first time to calculate the nucleon-nucleus optical potential. We also compare our predictions with the empirical potentials. The results indicate that the predictions of our microscopic potential are in better agreement with the experimental data as compared with the empirical global optical potentials.

Rafi, Syed; Haider, W.

198

Economic Energy Savings Potential in Federal Buildings  

SciTech Connect

The primary objective of this study was to estimate the current life-cycle cost-effective (i.e., economic) energy savings potential in Federal buildings and the corresponding capital investment required to achieve these savings, with Federal financing. Estimates were developed for major categories of energy efficiency measures such as building envelope, heating system, cooling system, and lighting. The analysis was based on conditions (building stock and characteristics, retrofit technologies, interest rates, energy prices, etc.) existing in the late 1990s. The potential impact of changes to any of these factors in the future was not considered.

Brown, Daryl R.; Dirks, James A.; Hunt, Diane M.

2000-09-04

199

Applying supersymmetry to energy dependent potentials  

SciTech Connect

We investigate the supersymmetry properties of energy dependent potentials in the D=1 dimensional space. We show the main aspects of supersymmetry to be preserved, namely the factorization of the Hamiltonian, the connections between eigenvalues and wave functions of the partner Hamiltonians. Two methods are proposed. The first one requires the extension of the usual rules via the concept of local equivalent potential. In this case, the superpotential becomes depending on the state. The second method, applicable when the potential depends linearly on the energy, is similar to what has been already achieved by means of the Darboux transform. -- Highlights: •Supersymmetry extended to energy dependent potentials. •Generalization of the concept of superpotential. •An alternative method used for linear E-dependence leads to the same results as Darboux transform.

Yekken, R. [Faculté de Physique, USTHB Bab Ezzouar, Alger (Algeria)] [Faculté de Physique, USTHB Bab Ezzouar, Alger (Algeria); Lassaut, M. [Groupe de Physique Théorique, Institut de Physique Nucléaire, IN2P3 - CNRS, Université Paris-Sud 11, 91406 Orsay Cedex (France)] [Groupe de Physique Théorique, Institut de Physique Nucléaire, IN2P3 - CNRS, Université Paris-Sud 11, 91406 Orsay Cedex (France); Lombard, R.J., E-mail: roland.lombard@laposte.net [Groupe de Physique Théorique, Institut de Physique Nucléaire, IN2P3 - CNRS, Université Paris-Sud 11, 91406 Orsay Cedex (France)

2013-11-15

200

Analysis of diffractive features in elastic scattering of 7Li by different target nuclei at different energies  

NASA Astrophysics Data System (ADS)

The diffractive features of angular distribution have been investigated by analyzing the experimental data for a set of elastic scattering processes of 7Li by different target nuclei at different laboratory energies. Both Frahn-Venter and McIntyre models are used to analyze experimental data of angular distribution for elastic scattering processes. The theoretical models can reasonably reproduce the general pattern of the data. Some geometrical parameters for colliding nuclei have been obtained from the elastic scattering processes. It is found that interpretation of the diffractive features of the data is model-independent. The values of extracted parameters, from adopted models, are found comparable to each other and to those of others. The total reaction cross section is correlated to the incident laboratory energy for each scattering and values of total reaction cross section are found comparable with those of others.

Badran, R. I.; Masri, Dana Al

2013-12-01

201

Analyzing power for p elastic scattering in the energy region of the Roper resonance  

SciTech Connect

High-precision measurements of the analyzing power A/sub N/ in p elastic scattering at p/sub / = 471--687 MeV/c are presented and compared with the results of recent N partial-wave analyses (PWA's) by the Karlsruhe-Helsinki, CMU-LBL, and VPI groups. While agreeing with the main features of the measured angular dependence of A/sub N/, the three PWA's yield larger values than the measurements at forward angles at p/sub / = 471, 547, and 625 MeV/c. At 687 MeV/c the PWA's do not agree with the data at far backward angles. We estimate the effect of our data on the phase shifts in this energy region, which includes the Roper resonance.

Mokhtari, A.; Briscoe, W.J.; Eichon, A.D.; Fitzgerald, D.H.; Kim, G.J.; Nefkens, B.M.K.; Wightman, J.A.; Sadler, M.E.

1986-01-01

202

Application of valence force field theory, tight binding approximation and Girifalco potential in the study of thermodynamic and elastic properties of C 60 in detail  

Microsoft Academic Search

In this paper we calculated the second order elastic constants (SOECs) of C60 using tight binding approximation (TBA) and valence force field theory (VFFT). To the SOECs obtained from Girifalco potential we added the contribution of Coloumb forces obtained through Martins prescription and the corrected values so obtained compare favorably with those of TBA and VFFT and also with literature

R. V. Gopala Rao; R. Venkatesh

2001-01-01

203

Elastic scattering of low-energy electrons by 1,4-dioxane.  

PubMed

We report calculated cross sections for elastic collisions of low-energy-electrons with 1,4-dioxane. Our calculations employed the Schwinger multichannel method with pseudopotentials and were carried out in the static-exchange and static-exchange plus polarization approximations for energies up to 30 eV. Our results show the presence of three shape resonances belonging to the Bu, Au, and Bg symmetries and located at 7.0 eV, 8.4 eV, and 9.8 eV, respectively. We also report the presence of a Ramsauer-Townsend minimum located at around 0.05 eV. We compare our calculated cross sections with experimental data and R-matrix and independent atom model along with the additivity rule corrected by using screening coefficients theoretical results for 1,4-dioxane obtained by Palihawadana et al. [J. Chem. Phys. 139, 014308 (2013)]. The agreement between the present and the R-matrix theoretical calculations of Palihawadana et al. is relatively good at energies below 10 eV. Our calculated differential cross sections agree well with the experimental data, showing only some discrepancies at higher energies. PMID:24832266

Barbosa, Alessandra Souza; Bettega, Márcio H F

2014-05-14

204

Potential to Kinetic Energy Demonstration: Principles of Energy Transfer  

NSDL National Science Digital Library

The Materials Science and Technology Teacher's Workshop (MAST) provides this activity to illustrate the principles of energy transfer. The demonstration uses a balance, matches, soda cans and a firecracker to show how energy can transfer between light, sound, heat and kinetic energy. Potential and kinetic energy are defined and explored. The lesson includes step by step directions for the experiment. Discussion questions are also included.

2012-03-07

205

Potential energy studies on silane dimers  

NASA Astrophysics Data System (ADS)

Intermolecular interactions and parameters for use in MD studies of large molecule systems have earlier been determined for hydrocarbons, carbon tetrahalides and sulfur. The paper reports a model representing nonbonding interactions between silane molecules, which were examined in the same way as hydrocarbons in an earlier (neopentane, isopropane, propane, and ethane) study. Intermolecular potentials were determined for 11 combinations of silane compound pairs (silane SiH 4, disilane Si 2H 6, trisilane Si 3H 8, isotetrasilane Si 4H 10 and neopentasilane Si 5H 12) with MP2/aug(df)-6-311G ?ab initio calculations. The most stable dimer configurations were identified. With use of the modified Morse potential model to represent the interactions, 276 new potential energy surfaces were generated for silane dimers. Separate and generic pair potentials were calculated for the silanes. The pair potentials can be used in MD studies of silanes.

Mahlanen, Riina; Pakkanen, Tapani A.

2011-04-01

206

Measurement of neutron elastic scattering cross sections for {sup 12}C, {sup 40}Ca, and {sup 208}Pb at energies from 65 to 225 MeV  

SciTech Connect

Differential neutron elastic scattering cross sections for {sup 12}C, {sup 40}Ca, and {sup 208}Pb have been measured using the continuum neutron source at the Los Alamos Neutron Science Center. The mean incident neutron kinetic energies ranged from 65 to 225 MeV. The large acceptance drift chamber based (n,p) recoil detector telescope spanned a center-of-mass angular range of 7 deg. to 23 deg. The measured cross sections are compared with calculations obtained with different optical model potentials, including predictions based on microscopic theory and phenomenology.

Osborne, J.H.; Brady, F.P.; Romero, J.L.; Ullmann, J.L.; Sorenson, D.S.; Ling, A.; King, N.S.P.; Haight, R.C.; Rapaport, J.; Finlay, R.W.; Bauge, E.; Delaroche, J.P.; Koning, A.J. [University of California, Davis, California 95616 (United States); Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Ohio University, Athens, Ohio 45701 (United States); Commissariat a l'Energie Atomique, Bruyeres-le-Chatel (France); Nuclear Research and Consulting Group, Petten (Netherlands)

2004-11-01

207

Biomass resource potential using energy crops  

SciTech Connect

Biomass energy crops can provide a significant and environmentally beneficial source of renewable energy feedstocks for the future. They can revitalize the agricultural sector of the US economy by providing profitable uses for marginal cropland. Energy crops include fast-growing trees, perennial grasses, and annual grasses, all capable of collecting solar energy and storing it as cellulosic compounds for several months to several years. Once solar energy is thus captured, it can be converted by means of currently available technologies to a wide variety of energy products such as electricity, heat, liquid transportation fuels, and gases. Experimental results from field trials have generated optimism that selected and improved energy crops, established on cropland with moderate limitations for crop production, have the potential for producing high yields. Both trees and grasses, under very good growing conditions, have produced average annual yields of 20 to 40 dry Mg ha{sup {minus}1} year{sup {minus}1}. Sorghum has shown especially high yields in the Midwest. Hybrids between sugar cane and its wild relatives, called energy cane, have yielded as much as 50 dry Mg ha{sup {minus}1} year{sup {minus}1} in Florida. These experimental results demonstrate that some species have the genetic potential for very rapid growth rates. New wood energy crop systems developed by the Department of Energy`s Biofuels Feedstock Development Program offer, at a minimum, a 100% increase in biomass production rates over the 2 to 4 Mg ha{sup {minus}1} year{sup {minus}1} of dry leafless woody biomass produced by most natural forest systems. Experimental data indicate that short rotation wood crops established on cropland with moderate limitations are capable of producing biomass yields of 8--20 dry Mg ha{sup {minus}1} year{sup {minus}1} with a present average about 11 dry Mg ha{sup {minus}1} year{sup {minus}1} on typical cropland sites.

Wright, L.L.; Cushman, J.H.; Martin, S.A.

1993-09-01

208

Estimation of Short-Run and Long-Run Elasticities of Energy Demand From Panel Data Using Shrinkage Estimators  

Microsoft Academic Search

This article discusses the problem of obtaining short-run and long-run elasticities of energy demand for each of 49 states in the United States using data for 21 years. Estimation using the time series data by each state gave several wrong signs for the coefficients. Estimation using pooled data was not valid because the hypothesis of homogeneity of the coefficients was

Robert P. Trost; Hongyi Li; Frederick Joutz

1997-01-01

209

Monte-Carlo model for elastic energy loss in a hydrodynamical background  

SciTech Connect

We present a computation of elastic energy loss of hard partons traversing the bulk hydrodynamical medium created in ultrarelativistic heavy-ion collisions. The model is based on perturbative QCD (pQCD) cross sections for 2{yields}2 processes in which a hard incoming parton is assumed to interact with a thermal parton from the medium. We model the interactions of this type in a Monte-Carlo framework to account properly for exact energy-momentum conservation, noneikonal parton propagation, parton conversion reactions, and the possibility to create additional hard recoiling partons from the medium. For the thermodynamical properties of the medium we use a hydrodynamical evolution model. We do not aim at a full description of high transverse momentum (P{sub T}) observables at this point. Rather, we view the model as a starting point in obtaining a baseline of what to expect under the assumptions that the medium is describable by thermal quasifree partons and that their pQCD interactions with the high-energy partons are independent. Deviations from this baseline then call for a more sophisticated medium description, as well as inclusion of higher-order processes and coherence effects in the pQCD scatterings.

Auvinen, Jussi; Eskola, Kari J.; Renk, Thorsten [Department of Physics, Post Office Box 35, FI-40014 University of Jyvaeskylae, Finland and Helsinki Institute of Physics, Post Office Box 64, FI-00014, University of Helsinki (Finland)

2010-08-15

210

Free energy of contact formation in proteins: Efficient computation in the elastic network approximation  

NASA Astrophysics Data System (ADS)

Biomolecular simulations have become a major tool in understanding biomolecules and their complexes. However, one can typically only investigate a few mutants or scenarios due to the severe computational demands of such simulations, leading to a great interest in method development to overcome this restriction. One way to achieve this is to reduce the complexity of the systems by an approximation of the forces acting upon the constituents of the molecule. The harmonic approximation used in elastic network models simplifies the physical complexity to the most reduced dynamics of these molecular systems. The reduced polymer modeled this way is typically comprised of mass points representing coarse-grained versions of, e.g., amino acids. In this work, we show how the computation of free energy contributions of contacts between two residues within the molecule can be reduced to a simple lookup operation in a precomputable matrix. Being able to compute such contributions is of great importance: protein design or molecular evolution changes introduce perturbations to these pair interactions, so we need to understand their impact. Perturbation to the interactions occurs due to randomized and fixated changes (in molecular evolution) or designed modifications of the protein structures (in bioengineering). These perturbations are modifications in the topology and the strength of the interactions modeled by the elastic network models. We apply the new algorithm to (1) the bovine trypsin inhibitor, a well-known enzyme in biomedicine, and show the connection to folding properties and the hydrophobic collapse hypothesis and (2) the serine proteinase inhibitor CI-2 and show the correlation to ? values to characterize folding importance. Furthermore, we discuss the computational complexity and show empirical results for the average case, sampled over a library of 77 structurally diverse proteins. We found a relative speedup of up to 10 000-fold for large proteins with respect to repeated application of the initial model.

Hamacher, Kay

2011-07-01

211

Bulk elastic moduli and solute potentials in leaves of freshwater, coastal and marine hydrophytes. Are marine plants more rigid?  

PubMed Central

Bulk modulus of elasticity (?), depicting the flexibility of plant tissues, is recognized as an important component in maintaining internal water balance. Elevated ? and comparatively low osmotic potential (??) may work in concert to effectively maintain vital cellular water content. This concept, termed the ‘cell water conservation hypothesis’, may foster tolerance for lower soil-water potentials in plants while minimizing cell dehydration and shrinkage. Therefore, the accumulation of solutes in marine plants, causing decreases in ??, play an important role in plant–water relations and likely works with higher ? to achieve favourable cell volumes. While it is generally held that plants residing in marine systems have higher leaf tissue ?, to our knowledge no study has specifically addressed this notion in aquatic and wetland plants residing in marine and freshwater systems. Therefore, we compared ? and ?? in leaf tissues of 38 freshwater, coastal and marine plant species using data collected in our laboratory, with additional values from the literature. Overall, 8 of the 10 highest ? values were observed in marine plants, and 20 of the lowest 25 ? values were recorded in freshwater plants. As expected, marine plants often had lower ??, wherein the majority of marine plants were below ?1.0 MPa and the majority of freshwater plants were above ?1.0 MPa. While there were no differences among habitat type and symplastic water content (?sym), we did observe higher ?sym in shrubs when compared with graminoids, and believe that the comparatively low ?sym observed in aquatic grasses may be attributed to their tendency to develop aerenchyma that hold apoplastic water. These results, with few exceptions, support the premise that leaf tissues of plants acclimated to marine environments tend to have higher ? and lower ??, and agree with the general tenets of the cell water conservation hypothesis.

Touchette, Brant W.; Marcus, Sarah E.; Adams, Emily C.

2014-01-01

212

Bulk elastic moduli and solute potentials in leaves of freshwater, coastal and marine hydrophytes. Are marine plants more rigid?  

PubMed

Bulk modulus of elasticity (?), depicting the flexibility of plant tissues, is recognized as an important component in maintaining internal water balance. Elevated ? and comparatively low osmotic potential (??) may work in concert to effectively maintain vital cellular water content. This concept, termed the 'cell water conservation hypothesis', may foster tolerance for lower soil-water potentials in plants while minimizing cell dehydration and shrinkage. Therefore, the accumulation of solutes in marine plants, causing decreases in ??, play an important role in plant-water relations and likely works with higher ? to achieve favourable cell volumes. While it is generally held that plants residing in marine systems have higher leaf tissue ?, to our knowledge no study has specifically addressed this notion in aquatic and wetland plants residing in marine and freshwater systems. Therefore, we compared ? and ?? in leaf tissues of 38 freshwater, coastal and marine plant species using data collected in our laboratory, with additional values from the literature. Overall, 8 of the 10 highest ? values were observed in marine plants, and 20 of the lowest 25 ? values were recorded in freshwater plants. As expected, marine plants often had lower ??, wherein the majority of marine plants were below -1.0 MPa and the majority of freshwater plants were above -1.0 MPa. While there were no differences among habitat type and symplastic water content (?sym), we did observe higher ?sym in shrubs when compared with graminoids, and believe that the comparatively low ?sym observed in aquatic grasses may be attributed to their tendency to develop aerenchyma that hold apoplastic water. These results, with few exceptions, support the premise that leaf tissues of plants acclimated to marine environments tend to have higher ? and lower ??, and agree with the general tenets of the cell water conservation hypothesis. PMID:24876296

Touchette, Brant W; Marcus, Sarah E; Adams, Emily C

2014-01-01

213

Some anomalies of the amplitude of elastic scattering of medium-energy nucleons by zero-spin nuclei. Applications of the K/umlt o/hler-Levintov theorem and catastrophe theory  

SciTech Connect

The optical model with phenomenological and microscopic (in the impulse approximation) optical potentials is used to calculate the amplitude of elastic scattering of nucleons with energy /ital E//sub /ital p//=100--1000 MeV by spin-zero nuclei. The results of these calculations demonstrate a high sensitivity of the real parts of this amplitude to variations in the geometrical parameters of the different components of the optical potential.

Zavarzina, V. P.; Stepanov, A. V.

1989-01-01

214

Elastic electron scattering and vibrational excitation of isoxazole molecules in the energy range from 2 to 20 eV  

NASA Astrophysics Data System (ADS)

Differential cross sections for elastic electron scattering and the excitation of the C-H vibrational modes of isoxazole molecules were measured in the energy range from 2 to 20 eV and over the scattering angle range from 10° to 180°. The cross sections at the scattering angles of and above 90° were accessible with the use of a magnetic angle changer. The differential cross sections were integrated to yield integral and momentum transfer cross sections. The negative ion resonances in the elastic scattering at 2.7 eV and in the vibrational excitation of isoxazole at 5.5 and 10 eV were observed. The present cross sections for elastic scattering are compared with the corresponding results in furan.

Linert, Ireneusz; Zubek, Mariusz

2012-08-01

215

Applications of an energy-momentum tensor in nonlinear elastodynamics : Pseudomomentum and eshelby stress in solitonic elastic systems  

NASA Astrophysics Data System (ADS)

IN CONTINUUM mechanics the pseudomomentum is the covariant material momentum whose associated flux in the balance law is Eshelby's "energy-momentum" tensor. The unbalance of pseudomomentum was previously shown to play a basic role in the formulation of configurational forces and path-independent integrals in the theory of elastic inhomogeneities and brittle fracture. Here, it is further shown to provide a fundamental conservation law for dispersive nonlinear elastic systems which exhibit soliton solutions. This is illustrated by both classical and grade-two elasticity with applications to the sine-Gordon, Boussinesq. sine-Gordon -d'Alembert and generalized Zakharov systems encountered in various bulk or surface wave-propagation problems. In these systems the nonconservation of global pseudomomentum may be used for a perturbational approach to nearly integrable systems so as to study the influence of dissipation and external sources (e.g. defects).

Maugin, Gérard A.

1992-10-01

216

Elastic and Irreversible Energies of a Two-Stage Martensitic Transformation in NiTi Utilizing Calorimetric Measurements  

NASA Astrophysics Data System (ADS)

Elastic energy and irreversible energy are quantified based on calorimetric measurements. We analyze energetics for each stage of the stress-free, thermally induced two-stage phase transformation A ? R ? B19' in an aged Ni-rich NiTi shape memory alloy. Heating/cooling rates are imposed from 1 K/min up to 100 K/min. We compare energetic analysis after multiple thermal cycles to virgin ( i.e., first-cycle) material. Fundamental thermodynamic formulations are applied from two perspectives: the free energy change d G, and the rate of change of free energy expressed as d G/d f m. Two measures of irreversible contributions are defined: the difference between the forward and reverse transformation heats, and the product of the entropy and the thermal hysteresis. Higher values are determined for the former. For scan rates of 10 K/min and greater, the energetic values become relatively stable. Substantial variations are evident at 1, 5, and 10 K/min. The scan rate impacts the elastic strain energy and irreversible energy of the B19' markedly compared with the R-phase transition. The findings are rationalized considering morphologic changes at the lower scan rates and the impacts on elastic and irreversible energies.

Lanba, Asheesh; Hamilton, Reginald F.

2014-06-01

217

Potential energy savings from aquifer thermal energy storage  

SciTech Connect

Pacific Northwest Laboratory researchers developed an aggregate-level model to estimate the short- and long-term potential energy savings from using aquifer thermal storage (ATES) in the United States. The objectives of this effort were to (1) develop a basis from which to recommend whether heat or chill ATES should receive future research focus and (2) determine which market sector (residential, commercial, or industrial) offers the largest potential energy savings from ATES. Information was collected on the proportion of US land area suitable for ATES applications. The economic feasibility of ATES applications was then evaluated. The potential energy savings from ATES applications was calculated. Characteristic energy use in the residential, commercial, and industrial sectors was examined, as was the relationship between waste heat production and consumption by industrial end-users. These analyses provided the basis for two main conclusions: heat ATES applications offer higher potential for energy savings than do chill ATES applications; and the industrial sector can achieve the highest potential energy savings for the large consumption markets. Based on these findings, it is recommended that future ATES research and development efforts be directed toward heat ATES applications in the industrial sector. 11 refs., 6 figs., 9 tabs.

Anderson, M.R.; Weijo, R.O.

1988-07-01

218

Phenomenon of Energy Focusing in Explosion Systems which Include High Modulus Elastic Elements  

NASA Astrophysics Data System (ADS)

The results of experimental studies of physical reasons and conditions of the phenomenon of energy focusing in explosion systems including high modulus elastic elements are presented. Experiments were conducted to study the conditions of this phenomenon for TG-40/60, SEP and Composition B. For each HE a number of experiments has been conducted for various heights of silicon carbide inserts. Presence or absence of a hole in the steel specimen was determined. Also a number of frame-by-frame recordings of the process with record step of 1 ?s have been performed. It is shown that the energy focusing phenomenon is reproduced for various high explosives. The phenomenon is observed in the conditions close to critical conditions of detonation transfer from an active to a passive HE charge. The best conditions for the phenomenon were observed for TG-40/60 for ceramic insert heights of 16.5 mm, 18 mm and 19.5-mm. Physical reason of focusing process is the propagation of a concave detonation wave into highly compressed HE and the formation of a Mach stem on the axis of HE charge.

Balagansky, I.; Hokamoto, K.; Manikandan, P.; Matrosov, A.; Stadnichenko, I.; Miyoshi, H.

2009-12-01

219

ElaStic: A tool for calculating second-order elastic constants from first principles  

NASA Astrophysics Data System (ADS)

Elastic properties play a key role in materials science and technology. The elastic tensors at any order are defined by the Taylor expansion of the elastic energy or stress in terms of the applied strain. In this paper, we present ElaStic, a tool that is able to calculate the full second-order elastic stiffness tensor for any crystal structure from ab initio total-energy and/or stress calculations. This tool also provides the elastic compliances tensor and applies the Voigt and Reuss averaging procedure in order to obtain an evaluation of the bulk, shear, and Young moduli as well as the Poisson ratio of poly-crystalline samples. In a first step, the space-group is determined. Then, a set of deformation matrices is selected, and the corresponding structure files are produced. In a next step, total-energy or stress calculations for each deformed structure are performed by a chosen density-functional theory code. The computed energies/stresses are fitted as polynomial functions of the applied strain in order to get derivatives at zero strain. The knowledge of these derivatives allows for the determination of all independent components of the elastic tensor. In this context, the accuracy of the elastic constants critically depends on the polynomial fit. Therefore, we carefully study how the order of the polynomial fit and the deformation range influence the numerical derivatives, and we propose a new approach to obtain the most reliable results. We have applied ElaStic to representative materials for each crystal system, using total energies and stresses calculated with the full-potential all-electron codes exciting and WIEN2k as well as the pseudo-potential code Quantum ESPRESSO.

Golesorkhtabar, Rostam; Pavone, Pasquale; Spitaler, Jürgen; Puschnig, Peter; Draxl, Claudia

2013-08-01

220

A variational definition of the strain energy for an elastic string  

Microsoft Academic Search

Using the variational point of view, the constitutive equations of an elastic one-dimensional string are deduced from the stress-strain relations of nonlinear three-dimensional elasticity, by passing to the limit when the other dimensions go to zero. The assumptions made on the three-dimensional model are not very restrictive.

Emilio Acerbi; Giuseppe Buttazzo; Danilo Percivale

1991-01-01

221

Cogeneration potential of energy conversion systems  

SciTech Connect

Energy conversion systems for industrial cogeneration, supplying both electricity and process heat, were characterized in order to match each candidate to specific industrial requirements. The ratio of power to process heat is shown to be a critical factor in achieving matches that produce appreciable fuel savings. Economic screening, based on return on incremental investment, further refines the selection. The potential national fuel savings in 1990 are developed for the energy conversion systems with the greatest impact at levels of 0% and a 20% return on investment.

Brown, D.H.

1982-08-01

222

Computed potential energy surfaces for chemical reactions  

NASA Technical Reports Server (NTRS)

The objective was to obtain accurate potential energy surfaces (PES's) for a number of reactions which are important in the H/N/O combustion process. The interest in this is centered around the design of the SCRAM jet engine for the National Aerospace Plane (NASP), which was envisioned as an air-breathing hydrogen-burning vehicle capable of reaching velocities as large as Mach 25. Preliminary studies indicated that the supersonic flow in the combustor region of the scram jet engine required accurate reaction rate data for reactions in the H/N/O system, some of which was not readily available from experiment. The most important class of combustion reactions from the standpoint of the NASP project are radical recombinaton reactions, since these reactions result in most of the heat release in the combustion process. Theoretical characterizations of the potential energy surfaces for these reactions are presented and discussed.

Walch, Stephen P.

1990-01-01

223

Solar-energy potential in Turkey  

Microsoft Academic Search

In this study, a new formula based on meteorological and geographical data was developed to determine the solar-energy potential in Turkey using artificial neural-networks (ANNs). Scaled conjugate gradient (SCG) and Levenberg–Marquardt (LM) learning algorithms and a logistic sigmoid transfer function were used in the network. Meteorological data for the last four years (2000?2003) from 18 cities (Bilecik, K?r?ehir, Akhisar, Bingöl,

Adnan Sözen; Erol Arcaklio?lu; Mehmet Özalp; E. Galip Kanit

2005-01-01

224

Potential energy surfaces for protonation of hydrochlorofluoromethanes  

Microsoft Academic Search

The proton affinities (PAs) and potential energy surfaces (PESs) of hydrochlorofluoromethanes (HCFMs) have been predicted by using Gaussian-3X (G3X) method. The G3X PAs agree with previous G3 predictions, while the large discrepancies between theoretical and experimental PAs persisted for CH2F2, CHF3, and CF3Cl. Protonated HCFMs usually have multiple structures, and structures with protonations at F-atom, [Methyl-FH]+, are the most stable.

Yi-Liang He; Liming Wang

2009-01-01

225

Convective Available Potential Energy of World Ocean  

NASA Astrophysics Data System (ADS)

Here, for the first time, we propose the concept of Ocean Convective Available Potential Energy (OCAPE), which is the maximum kinetic energy (KE) per unit seawater mass achievable by ocean convection. OCAPE occurs through a different mechanism from atmospheric CAPE, and involves the interplay of temperature and salinity on the equation of state of seawater. The thermobaric effect, which arises because the thermal coefficient of expansion increases with depth, is an important ingredient of OCAPE. We develop an accurate algorithm to calculate the OCAPE for a given temperature and salinity profile. We then validate our calculation of OCAPE by comparing it with the conversion of OCAPE to KE in a 2-D numerical model. We propose that OCAPE is an important energy source of ocean deep convection and contributes to deep water formation. OCAPE, like Atmospheric CAPE, can help predict deep convection and may also provide a useful constraint for modelling deep convection in ocean GCMs. We plot the global distribution of OCAPE using data from the World Ocean Atlas 2009 (WOA09) and see many important features. These include large values of OCAPE in the Labrador, Greenland, Weddell and Mediterranean Seas, which are consistent with our present observations and understanding, but also identify some new features like the OCAPE pattern in the Antarctic Circumpolar Current (ACC). We propose that the diagnosis of OCAPE can improve our understanding of global patterns of ocean convection and deep water formation as well as ocean stratification, the meridional overturning circulation and mixed layer processes. The background of this work is briefly introduced as below. Open-ocean deep convection can significantly modify water properties both at the ocean surface and throughout the water column (Gordon 1982). Open-ocean convection is also an important mechanism for Ocean Deep Water formation and the transport of heat, freshwater and nutrient (Marshall and Schott 1999). Open-ocean convection may arise through strong surface buoyancy fluxes (Schott et al. 1996), or by thermobaric instability (Akitomo 1999a, b). Ingersoll (2005) demonstrated that thermobaric-induced deep convection is due to the abrupt release of ocean potential energy into kinetic energy. In atmospheric dynamics, Convective Available Potential Energy (CAPE) has long been an important thermodynamic variable (Arakawa and Schubert 1974) that has been used to forecast moist convection (Doswell and Rasmussen 1994) and to test the performance of GCMs (Ye et al. 1998). However, the development of a similar diagnostic in the ocean has received little attention.; World Ocean Convective Available Potential Energy distribution in North-Hemisphere Autumn (J/kg)

Su, Z.; Ingersoll, A. P.; Thompson, A. F.

2012-12-01

226

The Wind Energy Potential of Iceland  

NASA Astrophysics Data System (ADS)

While Iceland has an abundant wind energy resource, its use for electrical power production has so far been limited. Electricity in Iceland is generated primarily from hydro- and geothermal sources, and adding wind energy has so far not been considered practical or even necessary. However, wind energy is becoming a more viable option, as opportunities for new hydro- or geothermal power installations become limited. In order to obtain an estimate of the wind energy potential of Iceland, a wind atlas has been developed as part of the joint Nordic project 'Improved Forecast of Wind, Waves and Icing' (IceWind). Downscaling simulations performed with the Weather Research and Forecasting (WRF) model were used to determine the large-scale wind energy potential of Iceland. Local wind speed distributions are represented by Weibull statistics. The shape parameter across Iceland varies between 1.2 and 3.6, with the lowest values indicative of near-exponential distributions at sheltered locations, and the highest values indicative of normal distributions at exposed locations in winter. Compared with summer, average power density in winter is increased throughout Iceland by a factor of 2.0 - 5.5. In any season, there are also considerable spatial differences in average wind power density. Relative to the average value within 10 km of the coast, power density across Iceland varies between 50 - 250%, excluding glaciers, or between 300 - 1500 W m-2 at 50 m above ground level in winter. At intermediate elevations of 500 - 1000 m above mean sea level, power density is independent of the distance to the coast. In addition to seasonal and spatial variability, differences in average wind speed and power density also exist for different wind directions. Along the coast in winter, power density of onshore winds is higher by 100 - 700 W m-2 than that of offshore winds. The regions with the highest average wind speeds are impractical for wind farms, due to the distances from road infrastructure and the power grid, as well as due to the harsh winter climate. However, even in easily accessible regions, wind energy potential in Iceland, as measured by annual average power density, is among the highest in Western Europe. Based on these results, 14 test sites were selected for more detailed analyses using the Wind Atlas Analysis and Application Program (WAsP). These calculations show that a modest wind farm of ten medium size turbines would produce more energy throughout the year than a small hydro power plant, making wind energy a viable additional option.

Nawri, Nikolai; Nína Petersen, Guðrún; Bjornsson, Halldór; Hahmann, Andrea N.; Jónasson, Kristján; Bay Hasager, Charlotte; Clausen, Niels-Erik

2014-05-01

227

Elastic Fluctuations and Rubber Elasticity  

NASA Astrophysics Data System (ADS)

A coarse-grained phenomenological model is constructed to describe both phonon fluctuations and elastic heterogeneities in rubbery materials. It is a nonlocal, spatially heterogeneous generalization of the classical model of rubber elasticity, and with a tunable repulsion interaction. This model can also be derived from the Vulcanization theory. The residual stress and the non-affine deformation field, as well as their correlations, are calculated perturbatively, to the leading order of quenched randomness. It is explicitly shown that the interplay between the repulsive interaction and quenched randomness induces non- affine deformation. The spatial correlations of the non- affine deformation field and residual stress exhibit power-law scaling, with no characteristic length scale. We also calculate the contributions to the elastic free energy from both thermal and quenched fluctuations for arbitrary deformation. We find that they naturally explain the universal features in the Mooney-Rivlin plot of the stress-strain curve for rubbery materials. The (disorder averaged) thermal fluctuation of monomers is shown to depend on deformation, and becomes anisotropic upon shear deformation, as long as the repulsive interaction is finite.

Xing, Xiangjun; Goldbart, Paul; Rradzihovsky, Leo

2006-03-01

228

Shallow and diffuse spin-orbit potential for proton elastic scattering from neutron-rich helium isotopes at 71 MeV/nucleon  

NASA Astrophysics Data System (ADS)

Vector analyzing powers for proton elastic scattering from 8He at 71 MeV/nucleon have been measured using a solid polarized proton target operated in a low magnetic field of 0.1 T. The spin-orbit potential obtained from a phenomenological optical model analysis is found to be significantly shallower and more diffuse than the global systematics of stable nuclei, which is an indication that the spin-orbit potential is modified for scattering involving neutron-rich nuclei. A close similarity between the matter radius and the root-mean-square radius of the spin-orbit potential is also identified.

Sakaguchi, S.; Uesaka, T.; Aoi, N.; Ichikawa, Y.; Itoh, K.; Itoh, M.; Kawabata, T.; Kawahara, T.; Kondo, Y.; Kuboki, H.; Nakamura, T.; Nakao, T.; Nakayama, Y.; Sakai, H.; Sasamoto, Y.; Sekiguchi, K.; Shimamura, T.; Shimizu, Y.; Wakui, T.

2013-02-01

229

Empirical bond order potential calculations of the elastic properties of epitaxial InGaSbAs layers  

Microsoft Academic Search

In this paper, we show the use of an optimally parameterized empirical potential of the Abell–Tersoff type and demonstrate that we can obtain a deep level of insight into the properties of the epitaxially grown quaternary alloy InGaAsSb. We find that the strain energy as a function of composition does not follow intuitive averages between the binary constituents and that

V. Haxha; R. Garg; M. A. Migliorato; IWD Drouzas; J. M. Ulloa; P. M. Koenraad; M. J. Steer; H. Y. Liu; M. J. Hopkinson; D. J. Mowbray

2009-01-01

230

Elastic proteins: biological roles and mechanical properties  

Microsoft Academic Search

The term 'elastic protein' applies to many structural proteins with diverse functions and mechanical properties so there is room for confusion about its meaning. Elastic implies the property of elasticity, or the ability to deform reversibly without loss of energy; so elastic proteins should have high resilience. Another meaning for elastic is 'stretchy', or the ability to be deformed to

John Gosline; Margo Lillie; Emily Carrington; Paul Guerette; Christine Ortlepp; Ken Savage

2002-01-01

231

The Li+-H2 system in a rigid-rotor approximation: potential energy surface and transport coefficients  

Microsoft Academic Search

An accurate potential energy surface for the Li+-H2 system has been calculated ab initio at an H-H distance of 1.449 a0, using an extended geminal model. The potential has been used to find elastic and inelastic total and transport cross sections, which have subsequently been used in moment-type transport calculations with a Kramers-Moyal-type expansion of the collision integral. The ion

H R Skullerud; D K Dysthe

2002-01-01

232

pi. ⁻ elastic scattering on \\/sup 12,13\\/C and \\/sup 16,18\\/O at low energies  

Microsoft Academic Search

pi..⁻ elastic scattering experiments on \\/sup 12,13\\/C at 29. and 49.5 MeV and on \\/sup 16,18\\/O at 29. MeV are presented. The ratio of as well as the ratio of ¹⁸O differential cross section to ¹⁶O differential cross section have been measured. Two optical potentials have been used to examine the sensitivity of the ratios to neutron-proton radius differences, model

W. Gyles; R. R. Johnson; T. Masterson; B. Bassalleck; T. Marks; K. L. Erdman; A. W. Thomas; D. R. Gill; C. Sabev; J. Arvieux; E. Rost; J. J. Kraushaar; J. Alster; M. Krell

1979-01-01

233

Momentum Distributions of Deuterons from Quasi-Elastic DD Scattering at High Energies.  

National Technical Information Service (NTIS)

The expressions for the momentum spectra of relativistic deuterons experiencing quasi-elastic (with target deuteron breakup) scattering on deuterons are obtained in the framework of the multiple nucleon-nucleon scattering model. The results of calculation...

L. S. Azhgirey S. V. Razin A. V. Tarasov V. V. Uzhinsky

1979-01-01

234

Energy Approach to Anomalous Damped Elastic-Plastic Response to Short Pulse Loading.  

National Technical Information Service (NTIS)

In beams with full-end constraints, loaded transversely by short pressure pulses, the effect of extensional plastic deformation is to make possible instabilities related to snap buckling in the elastic-plastic recovery after the first peak displacement (S...

G. Borino U. Perego P. S. Symonds

1989-01-01

235

Predicting the Drop Performance of Solder Joints by Evaluating the Elastic Strain Energy from High-Speed Ball Pull Tests  

NASA Astrophysics Data System (ADS)

Despite being expensive and time consuming, board-level drop testing has been widely used to assess the drop or impact resistance of the solder joints in handheld microelectronic devices, such as cellphones and personal digital assistants (PDAs). In this study, a new test method, which is much simpler and quicker, is proposed. The method involves evaluating the elastic strain energy and relating it to the impact resistance of the solder joint by considering the Young’s modulus of the bulk solder and the fracture stress of the solder joint during a ball pull test at high strain rates. The results show that solder joints can be ranked in order of descending elastic strain energy as follows: Sn-37Pb, Sn-1Ag-0.5Cu, Sn-3Ag-0.5Cu, and Sn-4Ag-0.5Cu. This order is consistent with the actual drop performances of the samples.

You, Taehoon; Kim, Yunsung; Kim, Jina; Lee, Jaehong; Jung, Byungwook; Moon, Jungtak; Choe, Heeman

2009-03-01

236

Energy evolution of the large-t elastic scattering and its correlation with multiparticle production  

SciTech Connect

It is emphasized that the collective dynamics associated with color confinement is dominating over a point-like mechanism related to a scattering of the proton constituents at the currently available values of the momentum transferred in proton elastic scattering at the LHC. Deep-elastic scattering and its role in the dissimilation of the absorptive and reflective asymptotic scattering mechanisms are discussed with emphasis on the experimental signatures associated with the multiparticle production processes.

Troshin, S. M. [Institute for High Energy Physics, Protvino, Moscow Region, 142281 (Russian Federation)

2013-04-15

237

Computed potential energy surfaces for chemical reactions  

NASA Technical Reports Server (NTRS)

A new global potential energy surface (PES) is being generated for O(P-3) + H2 yields OH + H. This surface is being fit using the rotated Morse oscillator method, which was used to fit the previous POL-CI surface. The new surface is expected to be more accurate and also includes a much more complete sampling of bent geometries. A new study has been undertaken of the reaction N + O2 yields NO + O. The new studies have focused on the region of the surface near a possible minimum corresponding to the peroxy form of NOO. A large portion of the PES for this second reaction has been mapped out. Since state to state cross sections for the reaction are important in the chemistry of high temperature air, these studies will probably be extended to permit generation of a new global potential for reaction.

Walch, Stephen P.; Levin, Eugene

1993-01-01

238

Energy Independent Optical Potential and Inverse Scattering from NonLocal Potential  

Microsoft Academic Search

An energy-independent optical potential for nucleon -nucleus scattering is formally derived. A simple relation between energy-dependent and energy-independent potentials is established, showing that the latter has the same thresholds as the former. A generalized dispersion relation for energy -independent potentials is found and compared with the conventional dispersion relation of the generalized energy-dependent optical potentials. An inverse scattering method for

Kok-Cheung Tam

1982-01-01

239

Low energy positron interactions with uracil-Total scattering, positronium formation, and differential elastic scattering cross sections.  

PubMed

Measurements of the grand total and total positronium formation cross sections for positron scattering from uracil have been performed for energies between 1 and 180 eV, using a trap-based beam apparatus. Angular, quasi-elastic differential cross section measurements at 1, 3, 5, 10, and 20 eV are also presented and discussed. These measurements are compared to existing experimental results and theoretical calculations, including our own calculations using a variant of the independent atom approach. PMID:25053319

Anderson, E K; Boadle, R A; Machacek, J R; Chiari, L; Makochekanwa, C; Buckman, S J; Brunger, M J; Garcia, G; Blanco, F; Ingolfsson, O; Sullivan, J P

2014-07-21

240

Potential energy landscape equation of state.  

PubMed

Depth, number, and shape of the basins of the potential energy landscape are the key ingredients of the inherent structure thermodynamic formalism introduced by Stillinger and Weber [F. H. Stillinger and T. A. Weber, Phys. Rev. A 25, 978 (1982)]. Within this formalism, an equation of state based only on the volume dependence of these landscape properties is derived. Vibrational and configurational contributions to pressure are sorted out in a transparent way. Predictions are successfully compared with data from extensive molecular dynamics simulations of a simple model for the fragile liquid orthoterphenyl. PMID:12059429

La Nave, Emilia; Mossa, Stefano; Sciortino, Francesco

2002-06-01

241

Potential Energy Savings from Aquifer Thermal Energy Storage.  

National Technical Information Service (NTIS)

Pacific Northwest Laboratory researchers developed an aggregate-level model to estimate the short- and long-term potential energy savings from using aquifer thermal storage (ATES) in the United States. The objectives of this effort were to (1) develop a b...

M. R. Anderson R. O. Weijo

1988-01-01

242

Elastic and other associated properties of C60  

Microsoft Academic Search

Considering that Coulomb interactions contribute a negligible amount to the cohesive energy in C60, which has an fcc structure at room temperature, we used Girifalco potential function in our calculations; C60 is spherical in nature and rotates rather freely at room temperature. From this potential we evaluated the second-order elastic constants (SOEC's), their pressure derivatives, and the third-order elastic constants

R. Venkatesh; R. V. Gopala Rao

1997-01-01

243

Valence force field theory, elastic, acoustic and thermodynamic properties and a potential function of TeO 2 glass  

Microsoft Academic Search

A short survey has been made on the extensive work that is being done on the pressure derivatives of the second order elastic constants (SOEC) to ascertain various properties of substances. Hence an attempt has been made to correlate the pressure derivatives to some properties of the substances. Thus some equations have been derived to correlate the Grüneisen parameter which

R. V Gopala Rao; R Venkatesh

2003-01-01

244

Dramatic Resonances in Low-Energy Electron Elastic Scattering from Rb, Cs, Ba, La and Fr Atoms: Signatures of Electron Affinities  

NASA Astrophysics Data System (ADS)

We predict dramatic resonances in low-energy electron elastic total cross sections for Rb, Cs, Ba, La and Fr atoms whose energy positions are identified with the electron affinities (EA's) for these atoms, preceded by shape resonances and Ramsauer-Townsend minima. This provides a new powerful theoretical method of determining unambiguous EA values for atoms. The extracted EA values for Rb, Cs, Ba and La atoms agree very well with the most recently measured values, but our value for Fr disagrees significantly with existing calculated values (there are no experimental EA's for the Fr atom). The calculation used the recent Regge-pole methodology [1] with a Thomas-Fermi potential incorporating the vital core- polarization interaction. Results will be compared with other available data.[1] D. Sokolovski, Z. Felfli, S. Yu. Ovchinnikov, J. H. Macek and A. Z. Msezane, Phys. Rev. A 76, 012705 (2007)

Msezane, A. Z.; Felfli, Z.; Sokolovski, Dmitri

2008-05-01

245

An Iterative Global Optimization Algorithm for Potential Energy Minimization  

Microsoft Academic Search

In this paper we propose an algorithm for the minimization of potential energy functions. The new algorithm is based on the differential evolution algorithm of Storn and Price (1). The algorithm is tested on two different potential energy functions. The first function is the Lennard Jones energy function and the second function is the many-body potential energy function of Tersoff

N. P. Moloi; M. M. Ali

2003-01-01

246

Elastic interaction energy between a silicon interstitial and a carbon substitutional in a silicon crystal  

NASA Astrophysics Data System (ADS)

The strain interaction energy between a silicon interstitial and a carbon substitutional in a silicon crystal was modeled by a continuum Green’s function method and by atomistic simulation. The interaction energy is proportional to d-3 , where d is separation distance between the defects. The pair interaction energy was found to be less than 0.04meV for d>6nm increasing to more than about 0.1meV for d<3nm . The energies are unlikely to influence the diffusional behavior of the defects except at distances of one or two unit cells. The potential between the point defects is repulsive if they are oriented along the (100) crystal axis, but attractive if they are positioned along (110) or (111).

Christmas, Ursula M. E.; Faux, David A.; Cowern, Nicholas E. B.

2007-11-01

247

Momentum-space calculation of electron—CO elastic collision  

NASA Astrophysics Data System (ADS)

We report a momentum-space study on low-energy electron-CO collisions. Elastic differential cross sections (DCS) are obtained using a static-exchange-optical (SEO) model for the incident energies of 2, 3, 5, and 10 eV. Polarization effect of higher reaction channels, including the ionization continuum, on the elastic collision is represented by an ab initio equivalent-local optical potential. The cross sections are compared with experimental measurements and other theoretical results.

Wang, Yuan-Cheng; Ma, Jia; Zhou, Ya-Jun

2013-02-01

248

Non-contacting transfer of elastic energy into explosive simulants for dynamic property estimation  

NASA Astrophysics Data System (ADS)

Non-contacting acoustical methods can be used to extract various material properties of liquid or solid samples without disturbing the sample. These methods are useful even in the lab since they do not involve coupling anything to the sample, which might change its properties. A forteriori, when dealing with potentially dangerous materials, non-contacting methods may be the only safe solutions to mechanical characterization. Here, we show examples of using laser ultrasound to remotely insonify and monitor the elastic properties of several granular explosive simulants. The relatively short near-infrared laser pulse length (a few hundred nanoseconds) provides a broad-band thermoelastic source of ultrasound; we intentionally stay in the thermoelastic regime to avoid damaging the material. Then, we use a scanning laser Doppler vibrometer to measure the ultrasonic response of the sample. LDV technology is well established and very sensitive at ultrasonic frequencies; atomic level motions can be measured with modest averaging. The resulting impulse response of the explosive simulant can be analyzed to determine decay rates and wave speeds, with stiffer samples showing faster wave speeds and lower decay rates. On the other hand, at the low-frequency end of the acoustic spectrum, we use an electronically phased array to couple into a freely suspended sample's normal modes. This allows us to gently heat up the sample (3 °C in just under 5 min, as shown with a thermal IR camera). In addition to the practical interest in making the sample more chemically visible through heat, these two measurements (low-frequency resonant excitation vs high-frequency wave propagation) bracket the frequency range of acoustic non-destructive evaluation methods available.

Greeney, Nathan S.; Strovink, Kurt M.; Scales, John A.; Jessop, Andrew M.; Stuart Bolton, J.; Watson, Christopher C.; Adams, Douglas E.

2014-05-01

249

Assessment of wind energy potential in Poland  

NASA Astrophysics Data System (ADS)

The aim of the presentation is to show the suitability of using numerical model wind speed forecasts for the wind power industry applications in Poland. In accordance with the guidelines of the European Union, the consumption of wind energy in Poland is rapidly increasing. According to the report of Energy Regulatory Office from 30 March 2013, the installed capacity of wind power in Poland was 2807MW from 765 wind power stations. Wind energy is strongly dependent on the meteorological conditions. Based on the climatological wind speed data, potential energy zones within the area of Poland have been developed (H. Lorenc). They are the first criterion for assessing the location of the wind farm. However, for exact monitoring of a given wind farm location the prognostic data from numerical model forecasts are necessary. For the practical interpretation and further post-processing, the verification of the model data is very important. Polish Institute Meteorology and Water Management - National Research Institute (IMWM-NRI) runs an operational model COSMO (Consortium for Small-scale Modelling, version 4.8) using two nested domains at horizontal resolutions of 7 km and 2.8 km. The model produces 36 hour and 78 hour forecasts from 00 UTC, for 2.8 km and 7 km domain resolutions respectively. Numerical forecasts were compared with the observation of 60 SYNOP and 3 TEMP stations in Poland, using VERSUS2 (Unified System Verification Survey 2) and R package. For every zone the set of statistical indices (ME, MAE, RMSE) was calculated. Forecast errors for aerological profiles are shown for Polish TEMP stations at Wroc?aw, Legionowo and ?eba. The current studies are connected with a topic of the COST ES1002 WIRE-Weather Intelligence for Renewable Energies.

Starosta, Katarzyna; Linkowska, Joanna; Mazur, Andrzej

2014-05-01

250

The role of chemical free energy and elastic strain in the nucleation of zirconium hydride  

NASA Astrophysics Data System (ADS)

In this work a combination of synchrotron X-ray diffraction and thermodynamic modelling has been used to study the dissolution and precipitation of zirconium hydride in ?-Zr establishing the role of elastic misfit strain and chemical free energy in the ? ? ? + ? phase transformation. The nucleation of zirconium hydride is dominated by the chemical free energy where the chemical driving force for hydride precipitation is proportional to the terminal-solid solubility for precipitation and can be predicted by a function that is analogous to the universal nucleation parameter for the bainite transformation in ferrous alloys. The terminal-solid solubility for precipitation was found to be kinetically limited ?287 °C at a cooling rate of 5 °C min-1 or greater. The terminal solubilities were established using an offset method applied to the lattice strain data where a resolution of ˜10 wppm H can be achieved in the -direction. This is aided by the introduction of intra-granular strains in the -direction during cooling as a result of the thermal expansion anisotropy which increases the anisotropy associated with the misfitting H atoms within the ?-Zr lattice. The partial molar volume of H in ?-Zr has been shown to be consistent with other metals with BCC, FCC and HCP crystal structures and independent of H concentration. The application of an offset method to lattice strain data has successfully been used to measure the TSSd temperature during heating and the TSSp temperature during cooling based on the tetragonal misfit of H in ?-Zr. The TSSp temperature was measured to a resolution of ˜10 wppm H independently of bulk texture which is an improvement over other techniques. The ? ? ? + ? transformation has been shown to be kinetically limited when the TSSp temperature is >287 °C at a cooling rate of 5°C min-1 or greater. The chemical driving force for ?-hydride nucleation is proportional to the TSSp temperature and can be predicted as a function of temperature by ?GN. This is consistent with the dislocation-based models for hydride nucleation and gives an activation energy that is inversely proportional to the chemical driving force for hydride nucleation. It was not possible to detect the preferential nucleation of ?-hydride and its evolution to ?-hydride using synchrotron radiation due to the detection limit for {1 1 1}?/? (>20 wppm H) reflection and the expected rapid transformation kinetics. With a reduction in the TSSp temperature, the chemical driving force for hydride precipitation increases, promoting the nucleation of a high density of smaller hydrides. Establishing the TSSp temperature where ?-hydrides form on slow cooling will define the minimum chemical driving force needed to transition from ?- to ?-hydride.

Barrow, A. T. W.; Toffolon-Masclet, C.; Almer, J.; Daymond, M. R.

2013-10-01

251

Potential of renewable energy alternatives in Australia  

Microsoft Academic Search

Australia is one of those countries that are considered rich and abundant in fossil fuel energy resources. It is important for Australia to regulate the use of conventional energy and attempt replacing these conventional energies with renewable energy (RE) resources. Renewable energy resources in Australia are widely categorised as solar energy, biomass, wave energy and wind energy. By increasing the

Talal Yusaf; Steven Goh; J. A. Borserio

2011-01-01

252

Measurement of the slope parameter of the diffraction cone of elastic pp scattering in the energy region 650--1000 MeV  

SciTech Connect

The absolute differential cross sections of elastic pp scattering in the momentum-transfer range 0.006< or approx. =Vertical Bar t Vertical Bar< or approx. =0.04 (GeV/c)/sup 2/ in the energy region 650--1000 MeV were measured. The energy dependence of the slope parameter of the diffraction cone was determined and the contribution of the spin amplitudes to the elastic forward pp scattering was estimated.

Velichko, G.N.; Vorob'ev, A.A.; Dobrovol'skii, A.V.; Zalite, Y.K.; Korolev, G.A.; Maev, E.M.; Terent'ev, N.K.; Ter'en, I.; Khanzadeev, A.V.

1981-06-05

253

The Elastic Strain Energy of Damaged Solids with Applications to Non-Linear Deformation of Crystalline Rocks  

NASA Astrophysics Data System (ADS)

Laboratory and field data indicate that rocks subjected to sufficiently high loads clearly deviate from linear behavior. Non-linear stress-strain relations can be approximated by including third and higher-order terms of the strain tensor in the elastic energy expression (e.g., the Murnaghan model). Such classical non-linear models are successful for calculating deformation of soft materials, for example graphite, but cannot explain with the same elastic moduli small and large non-linear deformation of stiff rocks, such as granite. The values of the third (higher-order) Murnaghan moduli estimated from acoustic experiments are one to two orders of magnitude above the values estimated from stress-strain relations in quasi-static rock-mechanics experiments. The Murnaghan model also fails to reproduce an abrupt change in the elastic moduli upon stress reversal from compression to tension, observed in laboratory experiments with rocks, concrete, and composite brittle material samples, and it predicts macroscopic failure at stress levels lower than observations associated with granite. An alternative energy function based on second-order dependency on the strain tensor, as in the Hookean framework, but with an additional non-analytical term, can account for the abrupt change in the effective elastic moduli upon stress reversal, and extended pre-yielding deformation regime with one set of elastic moduli. We show that the non-analytical second-order model is a generalization of other non-classical non-linear models, for example "bi-linear", "clapping non-linearity", and "unilateral damage" models. These models were designed to explain the abrupt changes of elastic moduli and non-linearity of stiff rocks under small strains. The present model produces dilation under shear loading and other non-linear deformation features of the stiff rocks mentioned above, and extends the results to account for gradual closure of an arbitrary distribution of initial cracks. The results provide a quantitative framework that can be used to model simultaneously, with a small number of coefficients, multiple observed aspects of non-linear deformation of stiff rocks. These include, in addition to the features mentioned above, stress-induced anisotropy and non-linear effects in resonance experiments with damaged materials.

Hamiel, Yariv; Lyakhovsky, Vladimir; Ben-Zion, Yehuda

2011-12-01

254

Induced Seismicity Potential of Energy Technologies  

NASA Astrophysics Data System (ADS)

Earthquakes attributable to human activities--``induced seismic events''--have received heightened public attention in the United States over the past several years. Upon request from the U.S. Congress and the Department of Energy, the National Research Council was asked to assemble a committee of experts to examine the scale, scope, and consequences of seismicity induced during fluid injection and withdrawal associated with geothermal energy development, oil and gas development, and carbon capture and storage (CCS). The committee's report, publicly released in June 2012, indicates that induced seismicity associated with fluid injection or withdrawal is caused in most cases by change in pore fluid pressure and/or change in stress in the subsurface in the presence of faults with specific properties and orientations and a critical state of stress in the rocks. The factor that appears to have the most direct consequence in regard to induced seismicity is the net fluid balance (total balance of fluid introduced into or removed from the subsurface). Energy technology projects that are designed to maintain a balance between the amount of fluid being injected and withdrawn, such as most oil and gas development projects, appear to produce fewer seismic events than projects that do not maintain fluid balance. Major findings from the study include: (1) as presently implemented, the process of hydraulic fracturing for shale gas recovery does not pose a high risk for inducing felt seismic events; (2) injection for disposal of waste water derived from energy technologies does pose some risk for induced seismicity, but very few events have been documented over the past several decades relative to the large number of disposal wells in operation; and (3) CCS, due to the large net volumes of injected fluids suggested for future large-scale carbon storage projects, may have potential for inducing larger seismic events.

Hitzman, Murray

2013-03-01

255

Double scattering measurement applied for heavy ion elastic scattering at intermediate energies  

NASA Astrophysics Data System (ADS)

The measurement of the left-right asymmetry in double scattering was applied to deduce the vector analyzing power for elastic scattering of 150 MeV 6Li on 12C. In order to reduce the instrumental asymmetry, the measurement was done at ?lab = 7.7° and 12.3° corresponding to the second and third maxima of the angular distribution of the differential cross section for elastic scattering. The magnetic spectrograph DUMAS blocked reaction particles other than elastic ones impinging on the second scatterer. Position sensitive SSDs used for the left-right detectors in the second scattering reduced the instrumental false asymmetry. This enables us to perform the asymmetry measurement with a precision better than 10 -2.

Tanaka, M.; Yamagata, T.; Nakayama, S.; Inoue, M.; Goto, K.; Katori, K.; Yanagi, M.; Ogata, H.

1988-04-01

256

Low-energy elastic electron scattering by tetrafluoromethane (CF[sub 4])  

SciTech Connect

We report cross sections for electronically elastic electron scattering by CF[sub 4] from 1 to 40 eV, calculated within the static-exchange approximation using the Schwinger multichannel method. Although the static-exchange approximation does not give results that are accurate in detail below 20 eV, it is useful in understanding resonant features in the elastic and vibrationally inelastic cross sections. Above 20 eV, where the static-exchange approximation is more reliable, we derive a dissociation cross section in fair agreement with experiment by subtracting our result from the measured total cross section. We compare our integral and differential cross sections with the results of recent elastic and vibrationally inelastic scattering experiments.

Winstead, C.; Sun, Q.; McKoy, V. (A. A. Noyes Laboratory of Chemical Physics, California Institute of Technology, Pasadena, California 91125 (United States))

1993-01-15

257

Commercial Building Toplighting: Energy Saving Potential and Potential Paths Forward.  

National Technical Information Service (NTIS)

This report defines the cost-effective opportunity available to building owners that provides reduction in energy expenditures with rapid returns on investment while providing relief to our increasingly taxed electrical infrastructure around the country. ...

2008-01-01

258

Certification and the potential energy landscape  

NASA Astrophysics Data System (ADS)

Typically, there is no guarantee that a numerical approximation obtained using standard nonlinear equation solvers is indeed an actual solution, meaning that it lies in the quadratic convergence basin. Instead, it may lie only in the linear convergence basin, or even in a chaotic region, and hence not converge to the corresponding stationary point when further optimization is attempted. In some cases, these non-solutions could be misleading. Proving that a numerical approximation will quadratically converge to a stationary point is termed certification. In this report, we provide details of how Smale's ?-theory can be used to certify numerically obtained stationary points of a potential energy landscape, providing a mathematical proof that the numerical approximation does indeed correspond to an actual stationary point, independent of the precision employed.

Mehta, Dhagash; Hauenstein, Jonathan D.; Wales, David J.

2014-06-01

259

Communication: Certifying the potential energy landscape.  

PubMed

It is highly desirable for numerical approximations to stationary points for a potential energy landscape to lie in the corresponding quadratic convergence basin. However, it is possible that an approximation may lie only in the linear convergence basin, or even in a chaotic region, and hence not converge to the actual stationary point when further optimization is attempted. Proving that a numerical approximation will quadratically converge to the associated stationary point is termed certification. Here, we apply Smale's ?-theory to stationary points, providing a certification serving as a mathematical proof that the numerical approximation does indeed correspond to an actual stationary point, independent of the precision employed. As a practical example, employing recently developed certification algorithms, we show how the ?-theory can be used to certify all the known minima and transition states of Lennard-Jones LJ(N) atomic clusters for N = 7, ..., 14. PMID:23656107

Mehta, Dhagash; Hauenstein, Jonathan D; Wales, David J

2013-05-01

260

An ab initio method for locating potential energy minima  

SciTech Connect

We study the potential energy landscape underlying the motion of monatomic liquids by quenching from random initial configurations (stochastic configurations) to the nearest local minimum of the potential energy. We show that this procedure reveals the underlying potential energy surface directly. This is in contrast to the common technique of quenching from a molecular dynamics trajectory which does not allow a direct view of the underlying potential energy surface, but needs to be corrected for thermodynamic weighting factors.

Bock, Nicolas [Los Alamos National Laboratory; Peery, Travis [Los Alamos National Laboratory; Venneri, Giulia [Los Alamos National Laboratory; Chisolm, Eric [Los Alamos National Laboratory; Wallace, Duane [Los Alamos National Laboratory; Lizarraga, Raquel [CHILE; Holmstrom, Erik [CHILE

2009-01-01

261

Layout design optimization for magneto-electro-elastic laminate composites for maximized energy conversion under mechanical loading  

NASA Astrophysics Data System (ADS)

Magneto-electro-elastic (MEE) laminate composites with piezoelectric and piezomagnetic phases can be utilized as materials providing energy conversion among magnetic, electric and mechanical energies. This work is concerned with the development of a systematic design method of MEE composites with maximized conversion of mechanical energy to electric and/or magnetic energy. To predict the energy conversion phenomena, a fully coupled MEE theory is employed. A composite plate is assumed to be simply supported and is discretized into a number of laminates for analysis using a semi-analytic finite element method. Since the optimal stacking sequences for piezoelectric/piezomagnetic phases and the optimal thickness for each phase must be simultaneously determined, we propose formulating the design problem as a topology optimization problem. To implement the topology optimization, two interpolation models, the standard SIMP (solid isotropic material with penalization) model and the micromechanics model, are investigated. After solving benchmark test problems, design examples dealing with multifunctional composites are considered.

Sun, Kyung Ho; Kim, Yoon Young

2010-05-01

262

Energy resource potential of natural gas hydrates  

USGS Publications Warehouse

The discovery of large gas hydrate accumulations in terrestrial permafrost regions of the Arctic and beneath the sea along the outer continental margins of the world's oceans has heightened interest in gas hydrates as a possible energy resource. However, significant to potentially insurmountable technical issues must be resolved before gas hydrates can be considered a viable option for affordable supplies of natural gas. The combined information from Arctic gas hydrate studies shows that, in permafrost regions, gas hydrates may exist at subsurface depths ranging from about 130 to 2000 m. The presence of gas hydrates in offshore continental margins has been inferred mainly from anomalous seismic reflectors, known as bottom-simulating reflectors, that have been mapped at depths below the sea floor ranging from about 100 to 1100 m. Current estimates of the amount of gas in the world's marine and permafrost gas hydrate accumulations are in rough accord at about 20,000 trillion m3. Disagreements over fundamental issues such as the volume of gas stored within delineated gas hydrate accumulations and the concentration of gas hydrates within hydrate-bearing strata have demonstrated that we know little about gas hydrates. Recently, however, several countries, including Japan, India, and the United States, have launched ambitious national projects to further examine the resource potential of gas hydrates. These projects may help answer key questions dealing with the properties of gas hydrate reservoirs, the design of production systems, and, most important, the costs and economics of gas hydrate production.

Collett, T. S.

2002-01-01

263

Computed potential energy surfaces for chemical reactions  

NASA Technical Reports Server (NTRS)

The minimum energy path for the addition of a hydrogen atom to N2 is characterized in CASSCF/CCI calculations using the (4s3p2d1f/3s2p1d) basis set, with additional single point calculations at the stationary points of the potential energy surface using the (5s4p3d2f/4s3p2d) basis set. These calculations represent the most extensive set of ab initio calculations completed to date, yielding a zero point corrected barrier for HN2 dissociation of approx. 8.5 kcal mol/1. The lifetime of the HN2 species is estimated from the calculated geometries and energetics using both conventional Transition State Theory and a method which utilizes an Eckart barrier to compute one dimensional quantum mechanical tunneling effects. It is concluded that the lifetime of the HN2 species is very short, greatly limiting its role in both termolecular recombination reactions and combustion processes.

Walch, Stephen P.

1988-01-01

264

Thermophotovoltaic energy conversion: Technology and market potential  

NASA Astrophysics Data System (ADS)

This report contains material displayed on poster panels during the Conference. The purpose of the contribution was to present a summary of the business overview of thermophotovoltaic generation of electricity and its market potential. The market analysis has shown that the TPV market, while currently still in an early nucleation phase, is evolving into a range of small niche markets out of which larger-size opportunities can emerge. Early commercial applications on yachts and recreational vehicles which require a quiet and emission-free compact electrical generator fit the current TPV technology and economics. Follow-on residential applications are attractive since they can combine generation of electricity with space and hot water heating in a co-generation system. Development of future markets in transportation, both private and communal or industrial, will be driven by legislation requiring emission-free vehicles, and by a reduction in TPV systems cost. As a result of ``moving down the learning curve,'' growing power and consumer markets are predicted to come into reach of TPV systems, a development favored by high overall energy conversion efficiency due to high radiation energy density and to high electric conversion efficiency available with photovoltaic cells.

Ostrowski, Leon J.; Pernisz, Udo C.; Fraas, Lewis M.

1996-02-01

265

Vanishing rainbows near orbiting and the energy dependence of rainbow scattering - Relation to properties of the potential. [molecular beam scattering cross sections  

NASA Technical Reports Server (NTRS)

The energy threshold behavior of elastic rainbow scattering near the transition to orbiting is derived. Analysis of the energy dependence of the rainbow angle shows that the full range from high energies down to orbiting can be fitted with two parameters. Thus, measurements of the rainbow angle can give essentially only two pieces of information about the potential. For potentials of common shapes, such measurements are sensitive to regions of the potential just beyond the minimum and give information about the shape of the potential in this range. However, neither a minimum nor a point of inflection in the potential is necessary for rainbow scattering.

Greene, E. F.; Hall, R. B.; Mason, E. A.

1975-01-01

266

Low-Energy Elastic Scattering of Electrons from Highly Polarizable Atoms  

Microsoft Academic Search

In elastic scattering of electrons from atomic systems it is necessary to include the effect of the polarization of the atomic target by the incident electron in order to obtain reliable results for cross sections and spin polarization parameters. For highly polarizable systems such as the alkalis or excited states of atoms, the perturbative polarized-orbital method [1] does not yield

Weixing Ji; R. P. McEachran; A. D. Stauffer

2000-01-01

267

Coda wave interferometry and the equilibration of energy in elastic media  

Microsoft Academic Search

Multiple-scattered waves usually are not useful for creating deterministic images of the interior of elastic media. However, in many applications, one is not so much interested in making a deterministic image as in detecting changes in the medium. Cases in point are volcano monitoring and measuring the change in hydrocarbon reservoirs during enhanced recovery operations. Coda wave interferometry is a

Roel Snieder

2002-01-01

268

Some Convergence Tests on Medium Energy Pion-Deuteron Elastic Scattering Amplitudes.  

National Technical Information Service (NTIS)

With the exact solution of a covariant multiple scattering model for elastic pion deuteron scattering as a standard, the convergence of the multiple scattering series and the sufficiency of the first order and on-shell second order scattering amplitudes a...

A. S. Rinat Y. Starkand

1979-01-01

269

Forward pd elastic scattering and total spin-dependent pd cross sections at intermediate energies  

Microsoft Academic Search

Spin-dependent total pd cross sections are considered using the optical theorem. For this aim the full spin dependence of the forward pd elastic scattering amplitude is considered in a model independent way. The single-scattering approximation is used to relate this amplitude to the elementary amplitudes of pp and pn scattering and the deuteron form factor. A formalism allowing to take

Yu. N. Uzikov; J. Haidenbauer

2009-01-01

270

Channel coupling effect and important role of imaginary part of coupling potential for high-energy heavy-ion scatterings  

NASA Astrophysics Data System (ADS)

The recent works by the present authors and their collaborator predicted that the real part of heavy-ion optical potentials changes its character from attraction to repulsion around the incident energy per nucleon E/A= 200-300 MeV on the basis of the complex G-matrix interaction and the double-folding model (DFM) and revealed that the three-body force plays an important role there. In the present paper, we have analyzed the energy dependence of the coupling effect with the microscopic coupled channel (MCC) method and its relation to the elastic and inelastic-scattering angular distributions in detail in the case of the 12C + 12C system in the energy range of E/A= 100-400 MeV. The large channel coupling effect is clearly seen in the elastic cross section although the incident energies are enough high. The dynamical polarization potential (DPP) is derived to investigate the channel coupling effect. Moreover, we analyze the effect of the imaginary part of the coupling potential on elastic and inelastic cross sections.

Furumoto, T.; Sakuragi, Y.

2013-01-01

271

On the global and regional potential of renewable energy sources  

Microsoft Academic Search

In this thesis, the central research question is: what can be the contribution of renewable energy sources to the present and future world and regional energy supply system. The focus is on wind, solar PV and biomass energy (energy crops) for electricity generation. For the assessment of the economic potential, we construct cost-supply curves. As the economic potential also depends

Monique Maria Hoogwijk

2004-01-01

272

Renewable energy costs, potentials, barriers: Conceptual issues  

Microsoft Academic Search

Renewable energy can become the major energy supply option in low-carbon energy economies. Disruptive transformations in all energy systems are necessary for tapping widely available renewable energy resources. Organizing the energy transition from non-sustainable to renewable energy is often described as the major challenge of the first half of the 21st century. Technological innovation, the economy (costs and prices) and

Aviel Verbruggen; Manfred Fischedick; William Moomaw; Tony Weir; Alain Nadaï; Lars J. Nilsson; John Nyboer; Jayant Sathaye

2010-01-01

273

Jumping sans legs: does elastic energy storage by the vertebral column power terrestrial jumps in bony fishes?  

PubMed

Despite having no obvious anatomical modifications to facilitate movement over land, numerous small fishes from divergent teleost lineages make brief, voluntary terrestrial forays to escape poor aquatic conditions or to pursue terrestrial prey. Once stranded, these fishes produce a coordinated and effective "tail-flip" jumping behavior, wherein lateral flexion of the axial body into a C-shape, followed by contralateral flexion of the body axis, propels the fish into a ballistic flight-path that covers a distance of multiple body lengths. We ask: how do anatomical structures that evolved in one habitat generate effective movement in a novel habitat? Within this context, we hypothesized that the mechanical properties of the axial skeleton play a critical role in producing effective overland movement, and that tail-flip jumping species demonstrate enhanced elastic energy storage through increased body flexural stiffness or increased body curvature, relative to non-jumping species. To test this hypothesis, we derived a model to predict elastic recoil work from the morphology of the vertebral (neural and hemal) spines. From ground reaction force (GRF) measurements and high-speed video, we calculated elastic recoil work, flexural stiffness, and apparent material stiffness of the body for Micropterus salmoides (a non-jumper) and Kryptolebias marmoratus (adept tail-flip jumper). The model predicted no difference between the two species in work stored by the vertebral spines, and GRF data showed that they produce the same magnitude of mass-specific elastic recoil work. Surprisingly, non-jumper M. salmoides has a stiffer body than tail-flip jumper K. marmoratus. Many tail-flip jumping species possess enlarged, fused hypural bones that support the caudal peduncle, which suggests that the localized structures, rather than the entire axial skeleton, may explain differences in terrestrial performance. PMID:24388492

Ashley-Ross, Miriam A; Perlman, Benjamin M; Gibb, Alice C; Long, John H

2014-02-01

274

Spatial mapping of renewable energy potential  

Microsoft Academic Search

An energy resource that is renewed by nature and whose supply is not affected by the rate of consumption is often termed as renewable energy. The need to search for renewable, alternate and non-polluting sources of energy assumes top priority for self-reliance in the regional energy supply. This demands an estimation of available energy resources spatially to evolve better management

T. V. Ramachandra; B. V. Shruthi

2007-01-01

275

Full potential study of the elastic, electronic, and optical properties of spinels MgIn{sub 2}S{sub 4} and CdIn{sub 2}S{sub 4} under pressure effect  

SciTech Connect

The structural, elastic, electronic, and optical properties of cubic spinel MgIn{sub 2}S{sub 4} and CdIn{sub 2}S{sub 4} compounds have been calculated using a full relativistic version of the full-potential linearized-augmented plane wave with the mixed basis FP/APW+lo method. The exchange and correlation potential is treated by the generalized-gradient approximation (GGA). Moreover, the Engel-Vosko GGA formalism is also applied to optimize the corresponding potential for band structure calculations. The ground state properties, including the lattice constants, the internal parameter, the bulk modulus, and the pressure derivative of the bulk modulus are in reasonable agreement with the available data. Using the total energy-strain technique, we have determined the full set of first-order elastic constants C{sub ij} and their pressure dependence, which have not been calculated or measured yet. The shear modulus, Young's modulus, and Poisson's ratio are calculated for polycrystalline XIn{sub 2}S{sub 4} aggregates. The Debye temperature is estimated from the average sound velocity. Electronic band structures show a direct band gap ({Gamma}-{Gamma}) for MgIn{sub 2}S{sub 4} and an indirect band gap (K-{Gamma}) for CdIn{sub 2}S{sub 4}. The calculated band gaps with EVGGA show a significant improvement over the GGA. The optical constants, including the dielectric function {epsilon}({omega}), the refractive index n({omega}), the reflectivity R({omega}), and the energy loss function L({omega}) were calculated for radiation up to 30 eV. -- Graphical abstract: Calculated total and partial densities of states for MgIn{sub 2}S{sub 4} and CdIn{sub 2}S{sub 4}

Semari, F. [Laboratoire des Materiaux Magnetiques, Departement de Physique, Faculte des Sciences, Universite Djillali Liabes de Sidi Bel Abbes, Sidi Bel Abbes 22000 (Algeria); Khenata, R. [Laboratoire de Physique Quantique et de Modelisation Mathematique (LPQ3M), Departement de Technologie, Universite de Mascara, Mascara 29000 (Algeria); Depatment of Physics and Astronomy, King Saud University, PO Box 2455, Riyadh 11451 (Saudi Arabia); Rabah, M. [Laboratoire des Materiaux Magnetiques, Departement de Physique, Faculte des Sciences, Universite Djillali Liabes de Sidi Bel Abbes, Sidi Bel Abbes 22000 (Algeria); Bouhemadou, A. [Depatment of Physics and Astronomy, King Saud University, PO Box 2455, Riyadh 11451 (Saudi Arabia); Laboratory for Developing New Materials and their Characterization, Faculty of Science, University of Setif, 19000 Setif (Algeria); Bin Omran, S. [Depatment of Physics and Astronomy, King Saud University, PO Box 2455, Riyadh 11451 (Saudi Arabia); Reshak, Ali H., E-mail: maalidph@yahoo.co.u [Institute of Physical Biology, South Bohemia University, Nove Hrady 373 33 (Czech Republic); School of Microelectronic Engineering, University Malaysia Perlis (UniMAP), Block A, Kompleks Pusat Pengajian, 02600 Arau Jejawi, Perlis (Malaysia); Rached, D. [Laboratoire des Materiaux Magnetiques, Departement de Physique, Faculte des Sciences, Universite Djillali Liabes de Sidi Bel Abbes, Sidi Bel Abbes 22000 (Algeria)

2010-12-15

276

Size dependent stability analysis of circular ultrathin films in elastic medium with consideration of surface energies  

NASA Astrophysics Data System (ADS)

In this article, analytical framework is developed for size dependent symmetric stability and self-instability of circular nanoplates including surface effects using modified Kirchhoff plate theory. The surrounding elastic medium is modeled as Winkler elastic foundation and its effect is comprehensively studied on self-instability problems. The derived explicit solutions contain Bessel functions with modified arguments reflecting the size dependency of the buckling loads. In order to check the results an inverse formulation is presented for effective Young's modulus using the buckling loads to be verified by previous experimental results for nanowires. Several numerical examples are given for two types of materials with positive and negative surface properties to show the general trends of size dependencies. Some problems and limitations are explored for consistency of results with experiments and suggestions for future works.

Assadi, Abbas; Farshi, Behrooz

2011-03-01

277

Antiplane shear Lamb's problem treated by gradient elasticity with surface energy  

Microsoft Academic Search

The consideration of higher-order gradient effects in a classical elastodynamic problem is explored in this paper. The problem is the anti-plane shear analogue of the well-known Lamb's problem. It involves the time-harmonic loading of a half-space by a single concentrated anti-plane shear line force applied on the half-space surface. The classical solution of this problem based on standard linear elasticity

H. G. Georgiadis; I. Vardoulakis

1998-01-01

278

Energy absorption during compression and impact of dry elastic-plastic spherical granules  

Microsoft Academic Search

The discrete modelling and understanding of the particle dynamics in fluidized bed apparatuses, mixers, mills and others are\\u000a based on the knowledge about the physical properties of particles and their mechanical behaviour during slow, fast and repeated\\u000a stressing. In this paper model parameters (modulus of elasticity, stiffness, yield pressure, restitution coefficient and strength)\\u000a of spherical granules (?-Al2O3, zeolites 4A and

Sergiy Antonyuk; Stefan Heinrich; Jürgen Tomas; Niels G. Deen; Maureen S. van Buijtenen; J. A. M. Kuipers

2010-01-01

279

Elastic scattering cross sections for neutrons with energies up to 200 MeV  

SciTech Connect

Elastic scattering cross sections for natural C and Ca targets from 5-25 degrees and 75-200 MeV have been measured using the White Neutron Source at the Los Alamos Meson Production Facility (LAMPF). A large acceptance drift chamber based (n,p) recoil detector telescope was used. This detector included 2 scintillating converters. The cross sections will be compared to models such as Kozak and Madland`s using Dirac phenomenology.

Osborne, J.H.; Brady, F.P.; Romero, J.L. [Univ. of California, Davis, CA (United States)] [and others

1993-10-01

280

Potential of renewable energy systems in China  

Microsoft Academic Search

Along with high-speed economic development and increasing energy consumption, the Chinese Government faces a growing pressure to maintain the balance between energy supply and demand. In 2009, China has become both the largest energy consumer and CO2 emitting country in the world. In this case, the inappropriate energy consumption structure should be changed. As an alternative, a suitable infrastructure for

Wen Liu; Henrik Lund; Brian Vad Mathiesen; Xiliang Zhang

2011-01-01

281

Potential contribution of the wastewater sector to energy supply.  

PubMed

The biological treatment of wastewater could yield high energy fuels such as methane and alcohols, however most conventional treatment systems do not recover this energy potential. with a simple model of the energy yields of various wastewater treatment technologies it is possible to demonstrate how minor shifts in technology selection can lead the industry from being identified as predominantly energy intensive, to being recognised as a source of energy resources. The future potential energy yield is estimated by applying energy yield factors to alternative use scenarios of the same wastewater loads. The method for identifying the energy potential of wastewater was demonstrated for the New Zealand wastewater sector, but can equally be applied to other countries or regions. The model suggests that by using technologies that maximise the recovery of energy from wastewater, the potential energy yield from this sector would be substantially increased (six fold for New Zealand). PMID:21866779

Heubeck, S; de Vos, R M; Craggs, R

2011-01-01

282

Temperature effects and resonance elastic cross section influence on secondary energy distributions of scattered neutrons in the resolved resonance region  

SciTech Connect

It is customary to neglect the effect of thermal motion (Doppler effect) and resonance behavior of elastic cross section on the energy distribution of scattered neutrons in the resonance region. But as has been shown earlier for {sup 238}U, there is certain effect of replacing usual step-function by more exact expression, where {sigma}{sub s} has resonance behavior The question of interest was to check the effect of replacing step distribution by more exact one for the simplest cylindrical two-zone cell with different V{sub mod} / V{sub f}. A code has been written to solve slowing-down equation from unit source in ultra-fine energy scale with two different kernels. Energy averaged cross sections were calculated for {sup 238}U and {sup 235}U. (authors)

Kolesov, V. V.; Ukraintsev, V. F. [Obninsk Inst. of Nuclear Power Engineering, Studgorodok 1, 249040 Obninsk, Kaluga reg. (Russian Federation)

2006-07-01

283

Mechanism of Resilin Elasticity  

PubMed Central

Resilin is critical in the flight and jumping systems of insects as a polymeric rubber-like protein with outstanding elasticity. However, insight into the underlying molecular mechanisms responsible for resilin elasticity remains undefined. Here we report the structure and function of resilin from Drosophila CG15920. A reversible beta-turn transition was identified in the peptide encoded by exon III and for full length resilin during energy input and release, features that correlate to the rapid deformation of resilin during functions in vivo. Micellar structures and nano-porous patterns formed after beta-turn structures were present via changes in either the thermal or mechanical inputs. A model is proposed to explain the super elasticity and energy conversion mechanisms of resilin, providing important insight into structure-function relationships for this protein. Further, this model offers a view of elastomeric proteins in general where beta-turn related structures serve as fundamental units of the structure and elasticity.

Qin, Guokui; Hu, Xiao; Cebe, Peggy; Kaplan, David L.

2012-01-01

284

Linear elasticity theory of pentagonal quasicrystals  

Microsoft Academic Search

We present general solutions of the inhomogeneous linear elastic equations for pentagonal quasicrystals. The equations are those obtained by minimizing the harmonic elastic energy which includes a nontrivial coupling between the phason and displacement variables. Our solutions are presented in terms of the Green's functions for the elastic equations and allow the solution of any inhomogeneous linear elastic problem for

Piali de; Robert A. Pelcovits

1987-01-01

285

Solar Energy Potential and Applications in Myanmar  

Microsoft Academic Search

Energy consumption is one of the indices in determining the levels of development of a nation. Therefore, availability of energy supply to all sectors of life in any country is crucial for its development. These exists shortage of all kinds of energy, particularly electricity which is badly needed for economic development. Electricity from the sun which is quite abundant in

Thet Thet; Han Yee; Su Su Win; Nyein Nyein Soe

286

Elastic pp scattering in the Coulomb-nuclear interference region at energies 500--1000 MeV  

SciTech Connect

The differential cross sections for elastic pp scattering at energies 648 and 992 MeV were measured in the momentum-transfer range 2 x 10/sup -3/< Vertical Bar t Vertical Bar <10/sup -2/ (GeV/c)/sup 2/. The scattered and recoil protons were recorded in the experiment simultaneously. The data are analyzed jointly with our earlier results in the energy range 500--1000 MeV. The ratio of the real and imaginary parts of the spin-independent forward-scattering amplitude is determined and agrees well with the results of dispersion-relation calculations. However, the obtained contribution of the spin-dependent amplitudes to the differential cross section is much lower than the calculated value.

Velichko, G.N.; Vorob'ev, A.A.; Zalite, Y.K.; Korolev, G.A.; Maev, E.M.; Terent'ev, N.K.; Khanzadeev, A.V.; Shchegel'skii, V.A.

1982-06-01

287

Analysis of Low-energy -4He Elastic Scattering Process in Direct Channel Regge-Pole Formalism  

NASA Astrophysics Data System (ADS)

The elastic scattering of low-energy -particles by a 4He target has been analysed within the frame-work of a modified Regge-Pole model which reproduces the partial wave phaseshifts in an elegant and simple way and describes all other relevant features of the scattering phenomena.Translated AbstractAnalyse des elastischen -4He-Streuungsprozesses bei niedrigen Energien im Direkt-Kanal-Regge-Pol-FormalismusDie elastische Streuung von -Teilchen niedriger Energie an einem 4He-Target wurde im Rahmen eines modifizierten Regge-Pol-Modells analysiert; dieses Modell stellt die Phasenverschiebungen der Partialwellen in eleganter und einfacher Weise dar und beschreibt alle anderen wesentlichen Aspekte des Streuvorganges.

Majumdar, D.; Chowdhury, A. Roy; Roy, T.

288

Solar energy in California industry - Applications, characteristics and potential  

Microsoft Academic Search

Results of a survey to determine the potential applicability of solar thermal energy to industrial processes in California are presented. It is found that if the heat for all industrial processes at temperatures below 212 F were supplied by solar energy, total state energy consumption could be reduced by 100 trillion Btus (2%), while the use of solar energy in

R. H. Barbieri; D. S. Pivirotto

1978-01-01

289

Energy conservation potential of surface modification technologies  

SciTech Connect

This report assesses the energy conservation impact of surface modification technologies on the metalworking industries. The energy conservation impact of surface modification technologies on the metalworking industries is assessed by estimating their friction and wear tribological sinks and the subsequent reduction in these sinks when surface modified tools are used. Ion implantation, coatings, and laser and electron beam surface modifications are considered.

Le, H.K.; Horne, D.M.; Silberglitt, R.S.

1985-09-01

290

Numerical investigation of the turbulent energy budget in the wake of freely oscillating elastically mounted cylinder at low reduced velocities  

NASA Astrophysics Data System (ADS)

We present a numerical study of the turbulent kinetic energy budget in the wake of cylinders undergoing Vortex-Induced Vibration (VIV). We show three-dimensional Large Eddy Simulations (LES) of an elastically mounted circular cylinder in the synchronization regime at Reynolds number of Re=8000. The Immersed Boundary Method (IBM) is used to account for the presence of the cylinder. The flow field in the wake is decomposed using the triple decomposition splitting the flow variables in mean, coherent and stochastic components. The energy transfer between these scales of motions are then studied and the results of the free oscillation are compared to those of a forced oscillation. The turbulent kinetic energy budget shows that the maximum amplitude of VIV is defined by the ability of the mean flow to feed energy to the coherent structures in the wake. At amplitudes above this maximum amplitude, the energy of the coherent structures needs to be fed additionally by small scale, stochastic energy in form of backscatter to sustain its motion. Furthermore, we demonstrate that the maximum amplitude of the VIV is defined by the integral length scale of the turbulence in the wake.

Sarkar, Abhishek; Schlüter, Jörg

2013-11-01

291

Zeta-function approach to Casimir energy with singular potentials  

SciTech Connect

In the framework of zeta-function approach the Casimir energy for three simple model system: single delta potential, step function potential and three delta potentials are analyzed. It is shown that the energy contains contributions which are peculiar to the potentials. It is suggested to renormalize the energy using the condition that the energy of infinitely separated potentials is zero which corresponds to subtraction all terms of asymptotic expansion of zeta-function. The energy obtained in this way obeys all physically reasonable conditions. It is finite in the Dirichlet limit, and it may be attractive or repulsive depending on the strength of potential. The effective action is calculated, and it is shown that the surface contribution appears. The renormalization of the effective action is discussed.

Khusnutdinov, Nail R. [Departamento de Fisica, Universidade Federal da Paraiba, Caixa Postal 5008, CEP 58051-970 Joao Pessoa, Pb (Brazil)

2006-01-15

292

Background Potential Resonance Effects in Low Energy Scattering of Neutrons from (12) C.  

National Technical Information Service (NTIS)

An R-matrix analysis of the total elastic scattering cross-section for neutron scattering off of C-12 below the first inelastic threshold is presented. Background potential scattering is included and gives a good fit to data.

L. Rikus K. Amos

1980-01-01

293

Analyzing powers in. pi. /sup +/p elastic scattering at intermediate energies  

SciTech Connect

The analyzing power, A/sub N/, has been measured for ..pi../sup +/p elastic scattering at p/sub ..pi../ = 471, 547, 625, and 687 MeV/c on a transversely polarized target. The results are compared with three recent partial-wave analyses for the isospin (3/2) channel. The agreement with our data for all three analyses is good at 471 MeV/c and reasonable at 547 and 625 MeV/c. At 687 MeV/c two of the analyses show a sharp maximum near costheta = -0.4 which is not seen in the data. There is no indication in our data of the existence of new, narrow ..delta.. resonances.

Mokhtari, A.; Briscoe, W.J.; Eichon, A.D.; Fitzgerald, D.H.; Kim, G.J.; Nefkens, B.M.K.; Wightman, J.A.; Adrian, S.D.; Sadler, M.E.; Walker, T.

1985-07-22

294

Correlation and size dependence of the lattice strain, binding energy, elastic modulus, and thermal stability for Au and Ag nanostructures  

NASA Astrophysics Data System (ADS)

As a group of wonder materials, gold and silver at the nanoscale demonstrate many intriguing properties that cannot be seen from their bulk counterparts. However, consistent insight into the mechanism behind the fascinations and their interdependence given by one integrated model is highly desirable. Based on Goldschmidt-Pauling's rule of bond contraction and its extension to the local bond energy, binding energy density, and atomic cohesive energy, we have developed such a model that is able to reconcile the observed size dependence of the lattice strain, core level shift, elastic modulus, and thermal stability of Au and Ag nanostructures from the perspective of skin-depth bond order loss. Theoretical reproduction of the measured size trends confirms that the undercoordination-induced local bond contraction, bond strength gain, and the associated binding energy density gain, the cohesive energy loss and the tunable fraction of such undercoordinated atoms dictate the observed fascinations, which should shed light on the understanding of the unusual behavior of other nanostructured materials as well.

Liu, X. J.; Zhou, Z. F.; Yang, L. W.; Li, J. W.; Xie, G. F.; Fu, S. Y.; Sun, C. Q.

2011-04-01

295

Energy sector and wind energy potential in Turkey  

Microsoft Academic Search

Turkey has very limited indigenous energy resources and has to import around 65% of primary energy to meet her needs. It is a large importer of primary energy despite having ample renewable energy sources.Turkey’s vibrant economy has led to increased energy demand in recent years. This situation is expected to continue in the near future because its economy is dependent

R. Tugrul Ogulata

2003-01-01

296

An Analysis of the Wind Energy Potential of Elazig, Turkey  

Microsoft Academic Search

In this study, the wind energy potential of Elazig is statistically analyzed based on hourly measured wind speed data over the five-year period from 1998 to 2002. The probability density distributions are derived from cumulative distribution functions. Two probability density functions are fitted to the measured probability distribution on a yearly basis. The wind energy potential of the location is

E. Kavak Akpinar; S. Akpinar

2004-01-01

297

Potential-energy surfaces for asymmetric heavy-ion reactions  

Microsoft Academic Search

We calculate the macroscopic potential energy of deformation as a function of mass asymmetry and distance between mass centers for shape configurations of interest in heavy-ion reactions. For the system300120 we also study the effect of adding microscopic shell and pairing corrections to the macroscopic potential energy. The shape configurations are generated by bringing together two separated spheres of unequal

P. Möller; J. R. Nix

1977-01-01

298

Potential energy surfaces for air triatomics. Volume 1: Literature review  

Microsoft Academic Search

An extensive literature review on the potential energy surfaces of fifteen atmospheric triatomic molecular systems has been made. The systems are water, nitrogen dioxide, ozone, carbon dioxide, nitrous oxide, and their singly charged positive and negative ions. The potential energy surface characteristics for each molecular system are summarized in the form of adiabatic correlation diagrams between the electronic states of

M. Krauss; D. G. Hopper; P. J. Fortune; A. C. Wahl; T. O. Tiernan

1975-01-01

299

Potential energy surfaces for study of heavy ion reactions  

Microsoft Academic Search

Potential energy surfaces are computed on the basis of an extended liquid drop model, taking into account the effects of nuclear surface diffusivity and the finite range of the nuclear interaction. Potential energy surfaces are constructed in the plane of central moments for symmetric and asymmetric systems.

D. N. Poenaru; M. Ivascu

1978-01-01

300

Potential energy surfaces for hydrocarbon molecules and ions  

Microsoft Academic Search

Studies of reaction dynamics and molecular spectroscopy rely on the concept of a potential energy surface (PES): the potential energy of the molecule or reaction complex as a function of the configuration of nuclei. In practice such a PES must be available in an analytical form that can be quickly evaluated and that has been fitted to the results of

Bastiaan J. Braams; Amit R. Sharma; Joel M. Bowman

2009-01-01

301

Potential Energy Sources Pose Mining Problem  

ERIC Educational Resources Information Center

Summarizes the discussions of a Division of Industrial and Engineering Chemistry symposium on solids handling for synthetic fuels production. Included is a description of technical difficulties with the use of coal seams and deposits of oil shale and oil sand as potential sources of fuel. (CC)

Chemical and Engineering News, 1974

1974-01-01

302

C-Phycocyanin Hydration Water Dynamics in the Presence of Trehalose: An Incoherent Elastic Neutron Scattering Study at Different Energy Resolutions  

PubMed Central

We present a study of C-phycocyanin hydration water dynamics in the presence of trehalose by incoherent elastic neutron scattering. By combining data from two backscattering spectrometers with a 10-fold difference in energy resolution we extract a scattering law S(Q,?) from the Q-dependence of the elastic intensities without sampling the quasielastic range. The hydration water is described by two dynamically different populations—one diffusing inside a sphere and the other diffusing quasifreely—with a population ratio that depends on temperature. The scattering law derived describes the experimental data from both instruments excellently over a large temperature range (235–320 K). The effective diffusion coefficient extracted is reduced by a factor of 10–15 with respect to bulk water at corresponding temperatures. Our approach demonstrates the benefits and the efficiency of using different energy resolutions in incoherent elastic neutron scattering over a large angular range for the study of biological macromolecules and hydration water.

Gabel, Frank; Bellissent-Funel, Marie-Claire

2007-01-01

303

Mechanisms of elastic energy dissipation in the transition layer between a coating and a substrate under contact interaction  

NASA Astrophysics Data System (ADS)

A theoretical and experimental analysis of the influence of the dispersed transition layer between a coating and a substrate on the development of deformation structures near the interface has been performed as part of an interdisciplinary study of the deformation and fracture of coating-substrate compositions under contact interaction. Elastic energy transfer from an indenter was simulated using excitable cellular automata taking into account the self-organization of translations and rotations of the structure near the interface. The effect of the transition layer between the coating and the substrate on the development of deformation structures during contact interaction with the indenter in three-point bending was studied experimentally using a TOMSC television-optical measuring complex.

Panin, V. E.; Moiseenko, D. D.; Panin, S. V.; Maksimov, P. V.; Goryacheva, I. G.; Cheng, C. H.

2014-03-01

304

Low energy super-elastic scattering studies of calcium over the complete angular range using a magnetic angle changing device  

NASA Astrophysics Data System (ADS)

Super-elastic scattering processes can be considered as the 'time reversal' of electron-photon coincidence measurements, with the advantage that data are accumulated thousands of times faster. This allows a far more extensive and accurate study of electron excitation of atoms which can also be excited using laser radiation. The application of a newly invented magnetic angle changing (MAC) device to these experiments has allowed the complete scattering geometry to be accessed for the first time, and experimental methods adopted in these new experiments are discussed here. Data are presented for excitation of the 41P1 state of calcium by electron impact at scattering angles from near 0° to beyond 180°, with incident energies of 45 eV and 55 eV. The results are compared to the DWBA theory of Stauffer and colleagues, with generally excellent agreement.

Hussey, Martyn; Murray, Andrew; MacGillivray, William; King, George

2008-03-01

305

Quasi-elastic and low-energy inelastic neutron scattering from fast ion conducting AgBr  

NASA Astrophysics Data System (ADS)

An apparently anomalous low-energy mode has been observed in AgBr close to the melting point, Tm, by inelastic neutron scattering using the IN6 time-of-flight spectrometer at ILL. Further measurements using the RITA triple-axis spectrometer at Risø National Laboratory show that in fact the “anomalous” behaviour is an artefact produced by the time-of-flight technique, coupled with a rapid expansion of the lattice close to melting. The behaviour of the 200 Bragg peak intensity as Tm is approached and is shown to be consistent with the proposal that a second-order transition to a fast ion conducting phase would occur at Tc=705 K> Tm,=701 K, but that melting occurs first. The observed quasi-elastic scattering is in excellent agreement with that expected from the ionic conductivity on the basis of the Nernst-Einstein relation.

Zetterström, P.; Chahid, A.; McGreevy, R. L.

1999-05-01

306

Solar energy potential in mountainous terrain  

Microsoft Academic Search

Mountainous terrain provides a special radiation climate that can be of advantage for solar energy conversion. Parameters influencing the general radiative climate are determined by the meso-scale of the locations. The major parameters are discussed and their respective influence on the radiative climate demonstrated using data recorded at various Alpine areas. Grid size for radiation networks has to be reduced

I. Dirmhirn

1977-01-01

307

On energy potential of millimeter-wave radar  

Microsoft Academic Search

One of the most serious problems of a short-pulse millimeter (MM) wave radar is deficit of its energy potential. The radar range upper limit of about a few kilometers is caused mostly by two factors: (1) low energy of transmitting signal pulses restricted by generator overheating or breakdown of waveguiding structures; and (2) decreasing of signal energy received because of

B. A. Rozanov; G. V. Cheslavsky

1998-01-01

308

The Biomass Potential of Turkey for Energy Production: Part II  

Microsoft Academic Search

Biomass is the major source of energy in rural Turkey. Biomass is used to meet a variety of energy needs including generating electricity, heating homes, fueling vehicles and providing process heat for industrial facilities. Biomass potential includes wood, animal and plant wastes. Among the biomass energy sources, fuelwood seems to be the most interesting because its share of the total

N. Saracoglu

2010-01-01

309

The Biomass Potential of Turkey for Energy Production: Part I  

Microsoft Academic Search

Biomass is the major source of energy in rural Turkey. Biomass is used to meet a variety of energy needs including generating electricity, heating homes, fueling vehicles and providing process heat for industrial facilities. Biomass potential includes wood, animal, and plant wastes. Among the biomass energy sources, fuelwood seems to be the most interesting because its share of the total

N. Saracoglu

2010-01-01

310

Effects of the Pauli principle on the 16O+ 28Si optical potential at 55 and 215 MeV laboratory energy  

Microsoft Academic Search

We find that the real part of the optical potential for the 16O+ 28Si system extracted from the elastic scattering data in the 55-215 MeV laboratory energy range undergoes a transition from a Brueckner to a folding-type shape. These changes agree with the theoretically expected reduction in the effects of the Pauli principle with increasing incident energy and suggest that

V. N. Bragin; R. Donangelo

1985-01-01

311

Virial exchange energies from model exact-exchange potentials.  

PubMed

It is shown by the example of Slater's averaged exchange potential that a poor approximation to the optimized effective potential (OEP) can yield a deceptively accurate energy via the conventional Kohn-Sham energy functional. For a trial exchange potential to be correct, its Kohn-Sham energy must coincide with the value obtained by the Levy-Perdew virial relation. Significant discrepancies between Kohn-Sham and the virial exchange energies are found for self-consistent Slater, Becke-Johnson, and effective local potentials (ELPs); their relative magnitudes are used to argue that, as approximations to the exact-exchange OEP, ELPs are the most accurate. Virial energy discrepancies vanish for Yang-Wu OEPs when the orbital and auxiliary basis sets are balanced, and remain surprisingly small for oscillatory OEPs obtained with unbalanced basis sets. PMID:18513004

Gaiduk, Alex P; Staroverov, Viktor N

2008-05-28

312

Coupled channel effect in elastic scattering and fusion for 6,7Li+28Si  

NASA Astrophysics Data System (ADS)

The fusion excitation and elastic angular distribution were measured for 6,7Li+28Si from below to above Coulomb barrier (? 3Vb) energies. The barrier distribution derived from the fusion data was found to be broad and asymmetric at the sub-barrier region, compared to 1D BPM estimation. Effect of rotational coupling on fusion was found to be not so dominant. Phenomenological optical potential parameters, with surface and volume type imaginary potentials, were obtained from f tting of elastic scattering data and energy dependence of real and imaginary surface strengths were investigated around the barrier. CDCC calculations considering only breakup of projectile were performed for 6,7Li+28Si with the elastic scattering data, using the code FRESCO. The effects of breakup of projectile on elastic cross section do not agree with the energy dependence of real and imaginary strength with volume type imaginary potential around the barrier.

Sinha, Mandira; Roy, Subinit; Basu, P.; Majumdar, H.; Santra, S.; Parkar, V. V.; Golda, K. S.; Kailas, S.

2011-10-01

313

Elastic cross sections for electron scattering from GeF4: Predominance of atomic-F in the high-energy collision dynamics  

NASA Astrophysics Data System (ADS)

We report absolute differential cross sections (DCSs) for elastic electron scattering from GeF4. The incident electron energy range was 3-200 eV, while the scattered electron angular range was typically 15°-150°. In addition, corresponding independent atom model (IAM) calculations, within the screened additivity rule (SCAR) formulation, were also performed. Those results, particularly for electron energies above about 10 eV, were found to be in good quantitative agreement with the present experimental data. Furthermore, we compare our GeF4 elastic DCSs to similar data for scattering from CF4 and SiF4. All these three species possess Td symmetry, and at each specific energy considered above about 50 eV their DCSs are observed to be almost identical. These indistinguishable features suggest that high-energy elastic scattering from these targets is virtually dominated by the atomic-F species of the molecules. Finally, estimates for the measured GeF4 elastic integral cross sections are derived and compared to our IAM-SCAR computations and with independent total cross section values.

Kato, H.; Suga, A.; Hoshino, M.; Blanco, F.; García, G.; Lima~o-Vieira, P.; Brunger, M. J.; Tanaka, H.

2012-04-01

314

Energy savings potential from energy-conserving irrigation systems  

SciTech Connect

This report systematically compares, within a consistent framework, the technical and economic characteristics of energy-conserving irrigation systems with those of conventional irrigation systems and to determine total energy savings. Levelized annual costs of owning and operating both energy-conserving and conventional irrigation systems have been developed and compared for all 17 states to account for the differences in energy costs and irrigation conditions in each state. Market penetration of energy-conserving systems is assessed for those systems having lower levelized annual costs than conventional systems performing the same function. Annual energy savings were computed by matching the energy savings per system with an assumed maximum market penetration of 100 percent in those markets where the levelized annual costs of energy-conserving systems are lower than the levelized annual costs of conventional systems.

Wilfert, G.L.; Patton, W.P.; Harrer, B.J.; Clark, M.A.

1982-11-01

315

Irradiation-induced damage in porous low- k materials during low-energy heavy-ion elastic recoil detection analysis  

NASA Astrophysics Data System (ADS)

With the implementation of time-of-flight elastic recoil detection (ToF-ERD) for the analysis of thin films with high depth resolution using a standard 'low-energy' accelerator, routine application of ERD in semiconductor technology becomes possible. In case of irradiation-sensitive materials, like organosilicate low- k films, the energetic incident beam damages the sample during the measurement, resulting in loss of the lighter elements and, as a consequence, altering the sample composition. The ion beam induced damage is investigated for 19F, 35Cl, 63Cu, 79Br and 127I beams at energies of 6-16 MeV and typical fluences for ERD analysis. By means of Fourier transform infrared (FTIR) spectroscopy a direct correlation between elemental losses and molecular broken bonds is obtained. The H losses can be described by the bulk molecular release model, with the associated release cross section for H linearly dependent on the energy deposited by the primary beam in the film.

Giangrandi, S.; Brijs, B.; Sajavaara, T.; Bender, H.; Iacopi, F.; Vantomme, A.; Vandervorst, W.

2006-08-01

316

Potential Energy Storage from Aquifer Thermal Energy Storage.  

National Technical Information Service (NTIS)

Aquifer thermal energy storage (ATES) is a technology that allows energy to be stored in aquifers and retrieved when needed. With this technology, energy is transferred to and from an aquifer through a network of wells. The aquifer operates as a containme...

M. R. Anderson R. O. Weijo J. L. Smoot

1987-01-01

317

Exploring wind energy potential off the California coast  

NASA Astrophysics Data System (ADS)

Wind energy represents the nearest term cost-effective renewable energy source. While efforts have been made to assess wind energy potential over land around the world, offshore wind energy resources are largely unexplored, in part because these regions have relatively sparse wind observations. In this study, the wind energy potential offshore of the California coast is evaluated using a well-tested high-resolution numerical model dataset. We found that along the coastline, the low-level winds exhibit strong spatial variation and are characterized by alternating windspeed maxima and minima near coastal promontories associated with the interaction between the marine boundary layer and coastal topography. Further analysis highlights the enormous and reliable wind energy development potential in these persistent offshore windspeed maxima.

Jiang, Qingfang; Doyle, James D.; Haack, Tracy; Dvorak, Michael J.; Archer, Cristina L.; Jacobson, Mark Z.

2008-10-01

318

Advanced Controls for Commercial Buildings: Barriers and Energy Savings Potential  

Microsoft Academic Search

Commercial buildings consume just over 17 quads of primary energy per year, about 17 percent of U.S. energy consumption. TIAX has carried out a two-phase study for the U.S. Department of Energy Building Technology Program (DOE\\/BT) that evaluates the energy saving potential of four advanced controls approaches in commercial buildings. This article presents the key results of the study, namely

Kurt W. Roth; Patricia Llana; Detlef Westphalen; Louis Quartararo; Michael Y. Feng

2006-01-01

319

Turbine under Gulf Stream: Potential energy source  

SciTech Connect

Turbine under the Gulf Stream (TUGS) is a project to design, build, and deploy the prototypes necessary to demonstrate the economic and technical feasibility of generating electric power from the Gulf Stream. The project is based in part on new generator designs and emerging materials technologies. Its successful completion would demonstrate the technology and produce prototype turbines that can be mass produced and sold with service support. Past research and experimentation indicates that energy can be generated from the Gulf Stream. Problems exist such as fluctuations in the current`s axis and inconsistency. Above all, the ocean is a difficult environment in which to work. Therefore, the question is not whether or not a generator can be put in the ocean to generate electricity, but rather can it be done in an economically and environmentally sound way and still be practical?

Venezia, W.A. [Naval Surface Warfare Center, Dania, FL (United States); Holt, J. [Harbor Branch Oceanographic Institution, Fort Pierce, FL (United States)

1995-09-01

320

The 4,5-Double Bond of Ceramide Regulates Its Dipole Potential, Elastic Properties, and Packing Behavior  

PubMed Central

The biological activities of ceramides show a large variation with small changes in molecular structure. To help understand how the structure regulates the activity of this important lipid second messenger, we investigated the interfacial features of a series of synthetic ceramide analogs in monomolecular films at the argon-buffer interface. To minimize differences arising from the N-acyl moiety, each analog had either a N-hexadecanoyl or a N-cis-4-hexadecenoyl moiety amide linked to the nitrogen of the sphingosine backbone. We found that the trans 4,5-unsaturation in the sphingosine backbone promoted closer packing and lower compressibilities of ceramide analogs in interfaces relative to comparable saturated species. Moreover, structures with this feature exhibited dipole potentials as much as 150–250 mV higher than comparable compounds lacking 4,5-unsaturation. The results support the hypothesis by M.C. Yappert and co-workers that trans unsaturation in the vicinity of C4 of the sphingoid backbone augments intramolecular hydration/hydrogen bonding in the polar region. This intramolecular hydration may allow the close packing of the ceramide molecules and engender their high dipole potentials. These properties of ceramides and their analogs may be important determinants of biological function.

Brockman, Howard L.; Momsen, Maureen M.; Brown, Rhoderick E.; He, Linli; Chun, Jiong; Byun, Hoe-Sup; Bittman, Robert

2004-01-01

321

Global permutationally invariant potential energy surface for ozone forming reaction  

NASA Astrophysics Data System (ADS)

We constructed new global potential energy surface for O + O2 --> O3 reaction. It is based on high level electronic structure theory calculations and employs fitting by permutationally invariant polynomial functions. This method of surface construction takes full advantage of permutation symmetry of three O nuclei and allows reducing dramatically the number of ab initio data points needed for accurate surface representation. New potential energy surface offers dramatic improvement over older surface of ozone in terms of dissociation energy and behavior along the minimum energy path. It can be used to refine the existing theories of ozone formation.

Ayouz, Mehdi; Babikov, Dmitri

2013-04-01

322

Variational formulation of a simplified strain gradient elasticity theory and its application to a pressurized thick-walled cylinder problem  

Microsoft Academic Search

A detailed variational formulation is provided for a simplified strain gradient elasticity theory by using the principle of minimum total potential energy. This leads to the simultaneous determination of the equilibrium equations and the complete boundary conditions of the theory for the first time. To supplement the stress-based formulation, the coordinate-invariant displacement form of the simplified strain gradient elasticity theory

X.-L. Gao; S. K. Park

2007-01-01

323

Evidence of Cholesterol Accumulated in High Curvature Regions: Implication to the Curvature Elastic Energy for Lipid Mixtures  

PubMed Central

Recent experiments suggested that cholesterol and other lipid components of high negative spontaneous curvature facilitate membrane fusion. This is taken as evidence supporting the stalk-pore model of membrane fusion in which the lipid bilayers go through intermediate structures of high curvature. How do the high-curvature lipid components lower the free energy of the curved structure? Do the high-curvature lipid components modify the average spontaneous curvature of the relevant monolayer, thereby facilitate its bending, or do the lipid components redistribute in the curved structure so as to lower the free energy? This question is fundamental to the curvature elastic energy for lipid mixtures. Here we investigate the lipid distribution in a monolayer of a binary lipid mixture before and after bending, or more precisely in the lamellar, hexagonal, and distorted hexagonal phases. The lipid mixture is composed of 2:1 ratio of brominated di18:0PC and cholesterol. Using a newly developed procedure for the multiwavelength anomalous diffraction method, we are able to isolate the bromine distribution and reconstruct the electron density distribution of the lipid mixture in the three phases. We found that the lipid distribution is homogenous and uniform in the lamellar and hexagonal phases. But in the distorted hexagonal phase, the lipid monolayer has nonuniform curvature, and cholesterol almost entirely concentrates in the high curvature region. This finding demonstrates that the association energies between lipid molecules vary with the curvature of membrane. Thus, lipid components in a mixture may redistribute under conditions of nonuniform curvature, such as in the stalk structure. In such cases, the spontaneous curvature depends on the local lipid composition and the free energy minimum is determined by lipid distribution as well as curvature.

Wang, Wangchen; Yang, Lin; Huang, Huey W.

2007-01-01

324

Evidence of Cholesterol Accumulated in High Curvature Regions: Implication ot the Curvature Elastic Energy for Lipid Mixtures  

SciTech Connect

Recent experiments suggested that cholesterol and other lipid components of high negative spontaneous curvature facilitate membrane fusion. This is taken as evidence supporting the stalk-pore model of membrane fusion in which the lipid bilayers go through intermediate structures of high curvature. How do the high-curvature lipid components lower the free energy of the curved structure? Do the high-curvature lipid components modify the average spontaneous curvature of the relevant monolayer, thereby facilitate its bending, or do the lipid components redistribute in the curved structure so as to lower the free energy? This question is fundamental to the curvature elastic energy for lipid mixtures. Here we investigate the lipid distribution in a monolayer of a binary lipid mixture before and after bending, or more precisely in the lamellar, hexagonal, and distorted hexagonal phases. The lipid mixture is composed of 2:1 ratio of brominated di18:0PC and cholesterol. Using a newly developed procedure for the multiwavelength anomalous diffraction method, we are able to isolate the bromine distribution and reconstruct the electron density distribution of the lipid mixture in the three phases. We found that the lipid distribution is homogenous and uniform in the lamellar and hexagonal phases. But in the distorted hexagonal phase, the lipid monolayer has nonuniform curvature, and cholesterol almost entirely concentrates in the high curvature region. This finding demonstrates that the association energies between lipid molecules vary with the curvature of membrane. Thus, lipid components in a mixture may redistribute under conditions of nonuniform curvature, such as in the stalk structure. In such cases, the spontaneous curvature depends on the local lipid composition and the free energy minimum is determined by lipid distribution as well as curvature.

Wang,W.; Yang, L.; Huang, H.

2007-01-01

325

Semiclassical energy levels and the corresponding potentials in nonhydrogenic ions  

NASA Astrophysics Data System (ADS)

A semiclassical expression is derived for the potential seen by an nl-shell electron in a nonhydrogenic ion. Corresponding energies Enl are compared with experimental values and with results of self-consistent-field calculations.

Pankratov, P.; Meyer-Ter-Vehn, J.

1992-11-01

326

Potential energy surfaces of HgH 2  

NASA Astrophysics Data System (ADS)

Potential energy surfaces for HgH 2 have been calculated using a non-empirical relativistic effective core potential incorporating configuration interaction by means of the CIPSI algorithm. Core valence polarization and correlation energy are included via a perturbative treatment. Spin-orbit coupling is introduced through an effective Hamiltonian. These theoretical results are used to discuss the experimental results of Breckenridge, Jouvet and Soep for the reaction Hg( 3P 1) + H 2 ? HgH( 2? +)+H.

Bernier, Anne; Millié, Philippe

1987-02-01

327

Improved potential energy surface for He-CO2  

Microsoft Academic Search

The anisotropic potential energy surface of He–CO2 is determined by the simultaneous analysis of newly measured high resolution total differential cross sections, differential energy loss spectra, new low temperature second virial coefficients, new diffusion, and viscosity data. The calculations are carried out in the infinite-order-sudden approximation. The repulsive anisotropy of the potential is determined from the rotationally inelastic cross sections

L. Beneventi; P. Casavecchia; F. Vecchiocattivi; G. G. Volpi; U. Buck; Ch. Lauenstein; R. Schinke

1988-01-01

328

Energy harvesting from axial fluid-elastic instabilities of a cylinder  

NASA Astrophysics Data System (ADS)

A flexible cylindrical system unstable to flutter oscillations is analysed from the perspective of energy harvesting. In this work we analyse the non-linear reduced order model of a two-degree of freedom system of cylinders modelled with discrete stiffness and damping. The non-linear system of equations is solved in terms of cylinder deflection angles. We seek the flow speed range over which flutter oscillations are stable and correspondingly amenable to energy harvesting. Energy harvesters are modelled as viscous dashpots and the coefficients of damping are parametrised in order to determine combinations that harvest maximum power. We show that for harvesting the maximum possible energy the viscous dashpot should be placed away from the region driving the instability and for this model the optimal location is the fixed end. This result is robust to flow speed variation, action of viscous drag and to variations in cylinder geometry.

Singh, Kiran; Michelin, Sébastien; de Langre, Emmanuel

2012-04-01

329

Sign of the real part of the elastic forward-scattering amplitude at high energies  

Microsoft Academic Search

For the reactions a+b-->a+b and a+b¯-->a+b¯ we obtain some general results about the sign of the real part of the forward-scattering amplitude, taking into account some general experimental features of the total cross sections. These results give numerical bounds on the energy beyond which the real part must remain positive for various reactions, neglecting some low-energy effects. (i) For crossing-symmetric

H. Cornille; R. E. Hendrick

1974-01-01

330

Potential energy surfaces in algebraic molecular models using coherent states  

Microsoft Academic Search

The potential energy surfaces provided by the coherent states formalism for the case of interacting one-dimensional oscillators is investigated. The case of two interacting oscillators modelled with Morse potentials are considered in detail. First the traditional treatment is presented in order to identify the need to establish a new transformation between the parameters and the classical variables that allow the

O. Castaños; R. Lemus

2010-01-01

331

Sturgeon Conservation: Insights From Elasticity Analysis  

Microsoft Academic Search

We use elasticity analyses for three sturgeon species, the shortnose sturgeon Acipenser brevirostrum, Atlantic sturgeon A. oxyrinchus, and white sturgeon A. transmontanus, to calculate the potential to increase population growth rate, l, by improving survival and fecundity. Elasticity analysis is a means of assessing changes to l resulting from conserva- tion initiatives. The elasticity of l to survival has a

MART R. GROSS; JOE REPKA; CORY T. ROBERTSON; DAVID H. SECOR; WEBB VAN WINKLE

332

Energy Consumption and Renewable Energy Development Potential on Indian Lands  

EIA Publications

Includes information on the electricity use and needs of Indian households and tribes, the comparative electricity rates that Indian households are paying, and the potential for renewable resources development of Indian lands.

Fred Mayes

2000-04-01

333

Elastic interaction energy calculations for Guinier--Preston zones in Al--Cu and CuBe  

Microsoft Academic Search

Computer experiments were performed in order to study elastic strain effects of small coherent precipitates. The model calculations were based on the harmonic theory of microscopic elasticity, which is a modification of lattice statics theory. The theoretical model requires as input only Born--Huang force constants of the host material and the elements of a symmetric stress-free distortion tensor for describing

E. Seitz; D. de Fontaine

1978-01-01

334

Thermal and elastic properties of solid neon  

NASA Astrophysics Data System (ADS)

We apply the improved effective potential Monte Carlo (IEP) and the improved self-consistent (ISC) theories to study the thermal and elastic properties of natural solid Ne. As a first orientation, we use the (12-6) Lennard-Jones (LJ) potential for first-neighbor forces only. The two parameters in the potential are determined from the 0 K lattice spacing and the sublimation energy of the crystal. We also create a realistic interatomic potential for the Ne dimer based on our study of the existing literature. When supplemented by many-body contributions, this potential is also used with ISC and IEP. The results are then compared with the experimental data in the literature. We conclude that our realistic potential which we regard as the best currently available is not significantly superior in accounting for the experimental data to the LJ potential, though both give a decent account of the experimental data.

Acocella, Dominic; Horton, George K.; Cowley, E. Roger

2000-04-01

335

The potential for renewable energy in industrial applications  

Microsoft Academic Search

To date, insufficient attention has been paid to the potential of renewable energy resources in industrial applications. Our analysis suggests that up to 21% of final energy demand and feedstock-use in the manufacturing industry sector could be of renewable origin by 2050, a five-fold increase over current levels in absolute terms. This estimate is considerably higher than other recent global

Emanuele Taibi; Dolf Gielen; Morgan Bazilian

336

Simple simulation for electron energy levels in geometrical potential wells  

Microsoft Academic Search

An octopus program is demonstrated to generate electron energy levels in three-dimensional geometrical potential wells. The wells are modeled to have shapes similar to cone, pyramid and truncated-pyramid. To simulate the electron energy levels in quantum mechanical scheme like the ones in parabolic band approximation scheme, the program is run initially to find a suitable electron mass fraction that can

Teparksorn Pengpan

2008-01-01

337

Regional Differences in the Price-Elasticity of Demand for Energy  

SciTech Connect

At the request of the National Renewable Energy Laboratory (NREL), the RAND Corporation examined the relationship between energy demand and energy prices with the focus on whether the relationships between demand and price differ if these are examined at different levels of data resolution. In this case, RAND compares national, regional, state, and electric utility levels of data resolution. This study is intended as a first step in helping NREL understand the impact that spatial disaggregation of data can have on estimating the impacts of their programs. This report should be useful to analysts in NREL and other national laboratories, as well as to policy nationals at the national level. It may help them understand the complex relationships between demand and price and how these might vary across different locations in the United States.

Bernstein, M. A.; Griffin, J.

2006-02-01

338

The Department of Defense energy vulnerabilities: Potential problems and observations  

NASA Astrophysics Data System (ADS)

The Department of Defense is almost entirely dependent on civilian energy supplies to meet its needs in both peacetime and periods of heightened conflict. There are a number of potential vulnerabilities to the continual and timely supply of energy to both the civilian and military sectors. These include denial of the energy resources themselves, disruption of critical transportation networks, destruction of storage facilities, and interruption of electrical power. This report briefly reviews the present situation for provision of energy from the civilian sector to the military. General vulnerabilities of the existing energy supply system are identified, along with the potential for armed aggression (including terrorist and sabotage activities) against the energy network. Conclusions and some tentative observations are made as to a proper response to the existing vulnerabilities.

Freiwald, D. A.; Berger, M. E.; Roach, J. F.

1982-08-01

339

Acousto-optically generated potential energy landscapes: potential mapping using colloids under flow.  

PubMed

Optical potential energy landscapes created using acousto-optical deflectors are characterized via solvent-driven colloidal particles. The full potential energy of both single optical traps and complex landscapes composed of multiple overlapping traps are determined using a simple force balance argument. The potential of a single trap is shown to be well described by a Gaussian trap with stiffness found to be consistent with those obtained by a thermal equilibrium method. We also obtain directly the depth of the well, which (as with stiffness) varies with laser power. Finally, various complex systems ranging from double-well potentials to random landscapes are generated from individually controlled optical traps. Predictions of these landscapes as a sum of single Gaussian wells are shown to be a good description of experimental results, offering the potential for fully controlled design of optical landscapes, constructed from single optical traps. PMID:23263108

Juniper, Michael P N; Besseling, Rut; Aarts, Dirk G A L; Dullens, Roel P A

2012-12-17

340

Electron-Hydrogen Elastic Scattering  

NASA Technical Reports Server (NTRS)

Scattering by single-electron systems is always of interest because the wave function of the target is known exactly. Various approximations have been employed to take into account distortion produced in the target. Among them are the method of polarized orbitals and the close coupling approximation. Recently, e-H and e-He+ S-wave scattering in the elastic region has been studied using the Feshbach projection operator formalism. In this approach, the usual Hartree-Fock and exchange potentials are augmented by an optical potential and the resulting phase shifts have rigorous lower bounds. Now this method is being applied to the e-H P-wave scattering in the elastic region. The number of terms in the Hylleraas-type wave function for the 1,3 P phase shifts is 84 and the resulting phase shifts (preliminary) are given. The results have been given up to five digits because to that accuracy they are rigorous lower bounds. They are in general agreement with the variational (VAR) results of Armstead, and those obtained from the intermediate energy R-matrix method (RM) of Scholz et al., and the finite element method (FEM) of Botero and Shertzer. The later two methods do not provide any bounds on phase shifts.

Bhatia, A. K.

2004-01-01

341

Analysis of Energy Dissipation and Deposition in Elastic Bodies Impacting at Hypervelocities.  

National Technical Information Service (NTIS)

A series of impact problems were analyzed using the Eulerian hydrocode CTH. The objective was to quantify the amount of energy dissipated locally by a projectile-infinite plate impact. A series of six impact problems were formulated such that the mass and...

D. F. Medina F. A. Allahdadi

1992-01-01

342

New Methods for Exploring QM:MM Potential Energy Landscapes  

NASA Astrophysics Data System (ADS)

In recent years, the applicability of quantum chemical methods for large system studies has been greatly enhanced by the development of hybrid QM:MM techniques. Despite these advancements, exploring the associated potential energy surfaces continues to present two key challenges. First, the QM energy and derivative evaluations may be too costly for simulations; and second, the system size for many QM:MM cases are too large to effectively store or use second-order information, an approach often used in QM studies to allow for larger integration steps and fewer QM evaluations of the potential energy surface. Our most recent work is focused on overcoming both computational bottlenecks. Using surface fitting models together with direct Hessian-vector and diagonalization algorithms, we are developing models that can accurately and efficiently explore QM:MM potential energy landscapes for very large systems. Our current development status and results from initial applications will be described.

Hratchian, Hrant P.

2010-06-01

343

Savings potential of ENERGY STAR (registered trademark) voluntary labeling programs  

SciTech Connect

In 1993 the U.S. Environmental Protection Agency (EPA) introduced ENERGY STAR (registered trademark), a voluntary labeling program designed to identify and promote energy-efficient products. Since then EPA, now in partnership with the U.S. Department of Energy (DOE), has introduced programs for more than twenty products, spanning office equipment, residential heating and cooling equipment, new homes, commercial and residential lighting, home electronics, and major appliances. We present potential energy, dollar and carbon savings forecasts for these programs for the period 1998 to 2010. Our target market penetration case represents our best estimate of future ENERGY STAR savings. It is based on realistic market penetration goals for each of the products. We also provide results under the assumption of 100% market penetration; that is, we assume that all purchasers buy ENERGY STAR-compliant products instead of standard efficiency products throughout the analysis period. Finally, we assess the sensitivity of our target penetration case forecasts to greater or lesser marketing success by EPA and DOE, lower-than-expected future energy prices, and higher or lower rates of carbon emission by electricity generators. The potential savings of ENERGY STAR are substantial. If all purchasers chose Energy Star-compliant products instead of standard efficiency products over the next 15 years, they would save more than $100 billion on their energy bills during those 15 years. (Bill savings are in 1995 dollars, discounted at a 4% real discount rate.)

Webber, Carrie A.; Brown, Richard E.

1998-06-19

344

Ab initio potential energy surfaces of the propane dimer  

NASA Astrophysics Data System (ADS)

The potential energy surface of a model propane dimer was systematically mapped with quantum chemical calculations. The calculations included approximately 12 separation distances between the monomers for each of 121 different relative geometries, or 1487 different configurations. The generated potential energy map reveals that the most attractive interactions are those having a maximum number of close contacts between carbon and hydrogen. The potential well depth of the most attractive orientation found was -1.625 kcal mol-1. The complete ab initio energy surface was fitted to a simple model consisting of pairwise-additive interatomic potentials, each modeled with a modified Morse function of interatomic distance. The resultant model accurately represents the entire propane dimer ab initio energy surface. The efficacy of the generated parameter set was tested with previously published ethane dimer energies and propane routes not included in fitting. The new parameter set is consistent with these results indicating a high level of transferability for the interatomic C-H, C-C, and H-H potentials obtained.

Jalkanen, Jukka-Pekka; Mahlanen, Riina; Pakkanen, Tapani A.; Rowley, Richard L.

2002-01-01

345

Optimizing potential energy functions for maximal intrinsic hyperpolarizability  

SciTech Connect

We use numerical optimization to study the properties of (1) the class of one-dimensional potential energy functions and (2) systems of point nuclei in two dimensions that yield the largest intrinsic hyperpolarizabilities, which we find to be within 30% of the fundamental limit. In all cases, we use a one-electron model. It is found that a broad range of optimized potentials, each of very different character, yield the same intrinsic hyperpolarizability ceiling of 0.709. Furthermore, all optimized potential energy functions share common features such as (1) the value of the normalized transition dipole moment to the dominant state, which forces the hyperpolarizability to be dominated by only two excited states and (2) the energy ratio between the two dominant states. All optimized potentials are found to obey the three-level ansatz to within about 1%. Many of these potential energy functions may be implementable in multiple quantum well structures. The subset of potentials with undulations reaffirm that modulation of conjugation may be an approach for making better organic molecules, though there appear to be many others. Additionally, our results suggest that one-dimensional molecules may have larger diagonal intrinsic hyperpolarizability {beta}{sub xxx}{sup int} than higher-dimensional systems.

Zhou Juefei; Szafruga, Urszula B.; Kuzyk, Mark G. [Department of Physics and Astronomy, Washington State University, Pullman, Washington 99164-2814 (United States); Watkins, David S. [Department of Physics and Astronomy, Washington State University, Pullman, Washington 99164-2814 (United States); Department of Mathematics, Washington State University, Pullman, Washington 99164-3113 (United States)

2007-11-15

346

Solar energy in California industry - Applications, characteristics and potential  

NASA Technical Reports Server (NTRS)

Results of a survey to determine the potential applicability of solar thermal energy to industrial processes in California are presented. It is found that if the heat for all industrial processes at temperatures below 212 F were supplied by solar energy, total state energy consumption could be reduced by 100 trillion Btus (2%), while the use of solar energy in processes between 212 and 350 F could displace 500 trillion Btus. The issues and problems with which solar energy must contend are illustrated by a description of fluid milk processing operations. Solar energy application is found to be technically feasible for processes with thermal energy requirements below 212 F, with design, and degree of technical, economic and management feasibility being site specific. It is recommended that the state provide support for federal and industrial research, development and demonstration programs in order to stimulate acceptance of solar process heat application by industry.

Barbieri, R. H.; Pivirotto, D. S.

1978-01-01

347

Global Onshore Wind Energy Potential and Its Uncertainties  

NASA Astrophysics Data System (ADS)

Wind power, a clean and renewable energy resource, can play an important role in providing energy and reducing greenhouse gas emissions. Yet there are substantial and important uncertainties about the potential costs and supplies of wind that influence our ability to understand today the strategic role of wind power in the future. A detailed global assessment of onshore wind energy potential and its uncertainties will help decision-makers develop policies and strategies to meet energy and environmental goals. In this study, we assess the technical and economic potential of onshore wind energy and its spatial distribution using reanalysis wind speed data from the National Centers for Environmental Modeling (Figure 1). The study focuses in particular in exploring a range of uncertainties that impact the economic potential of wind power by constructing quantitative scenarios for eight key physical and economic parameters. We present quantification of the impact of uncertainties in these parameters, focusing on areas relevant to geoscience research (Figure 2). The amount of economic potential of wind energy depends strongly on several uncertain parameters such as wind speed, turbine cost, and land-suitability. The distribution of wind speed at fine temporal and spatial scales is a key parameter, but is not well quantified in many regions of the world. Reanalysis datasets with more accurate wind fields are a first step, along with computationally tractable downscaling methodologies. Another key assumption is land-suitability, which is the fraction of a particular land-cover type assumed to be available for wind farm development. There is currently little scientific basis for land-suitability assumptions. While some of the data needed for progress in these areas is readily available, such as high-resolution land-cover and terrain data, further advances are likely to require new methodologies and inter-disciplinary collaboration. We outline a number of areas where further research is needed to construct improved estimates of global wind energy potential.

Zhou, Y.; Clarke, L.; Luckow, P.; Smith, S.

2011-12-01

348

The Measurements of the Differential Elastic Neutron Cross-Sections of Carbon for Energies from 2 TO 133 keV  

NASA Astrophysics Data System (ADS)

The measurements of the differential elastic neutron cross-sections of carbon have been carried out at the Kyiv Research Reactor (KRR) using the neutron filter beam technique. Experimental set-up for detection of scattered neutrons has been installed at the eighth horizontal channel of the KRR. The quasi-mono-energetic neutron lines with mean energies 2, 59 and 133 keV were formed by composite filters. The measurements of the angle distribution of scattering neutrons on carbon samples were executed at angles 30°, 55°, 90°, 125° and 150° for three neutron energies. To determine the differential elastic neutron cross-section on carbon d?/d?, the relative method of measurement was used. The isotope 208Pb was used as a standard. The normalization factor, which is a function of detector efficiency, thickness of the carbon samples, thickness of the Pb-208 sample, geometry, etc., for each sample and for each filter energy has been obtained through Monte Carlo calculations by means of own codes. The results of measurements of the differential elastic neutron cross sections on carbon samples at reactor neutron filtered beams with energies 2, 59, and 133 keV have been compared with the known experimental data from database EXFOR/CSISRS.

Gritzay, Olena; Kolotyi, Volodymyr; Pshenychnyi, Volodymyr; Klimova, Nataliia; Libman, Volodymyr; Venedyktov, Vitalii; Richardson, Jeffery; Sale, Kenneth

2009-08-01

349

Improved potential energy curve and vibrational energies for the electronic ground state of the hydrogen molecule  

Microsoft Academic Search

The potential energy curve for the electronic ground state of the hydrogen molecule has been recomputed for intermediate and large internuclear separations. For 2.4 <= R <= 8.0 a.u. the previous potential energy curve has been improved. The largest improvement amounts to 5.5 cm-1, and was obtained in the vicinity of R = 4.4 a.u.. Using the new potential energy

W. Kolos; L. Wolniewicz

1975-01-01

350

Collisionless Plasma Modeling in an Arbitrary Potential Energy Distribution  

NASA Technical Reports Server (NTRS)

A new technique for calculating a collisionless plasma along a field line is presented. The primary feature of the new model is that it can handle an arbitrary (including nonmonotonic) potential energy distribution. This was one of the limiting constraints on the existing models in this class, and these constraints are generalized for an arbitrary potential energy composition. The formulation for relating current density to the field-aligned potential as well as formulas for density, temperature and energy flux calculations are presented for several distribution functions, ranging from a bi-Lorentzian with a loss cone to an isotropic Maxwellian. A comparison of these results with previous models shows that the formulation reduces.to the earlier models under similar assumptions.

Liemohn, M. W.; Khazanov, G. V.

1997-01-01

351

Saturation wind power potential and its implications for wind energy.  

PubMed

Wind turbines convert kinetic to electrical energy, which returns to the atmosphere as heat to regenerate some potential and kinetic energy. As the number of wind turbines increases over large geographic regions, power extraction first increases linearly, but then converges to a saturation potential not identified previously from physical principles or turbine properties. These saturation potentials are >250 terawatts (TW) at 100 m globally, approximately 80 TW at 100 m over land plus coastal ocean outside Antarctica, and approximately 380 TW at 10 km in the jet streams. Thus, there is no fundamental barrier to obtaining half (approximately 5.75 TW) or several times the world's all-purpose power from wind in a 2030 clean-energy economy. PMID:23019353

Jacobson, Mark Z; Archer, Cristina L

2012-09-25

352

Contribution to the Study of the Elastic Scattering of Photons on Nucleons at Low and Intermediate Energies.  

National Technical Information Service (NTIS)

The elastic gamma -nucleon scattering represents an indirect powerful method for the nucleon structure investigation. Some theoretical aspects of this problem are treated in the presented thesis. After a general introduction into the subject and a short r...

I. Guiasu

1978-01-01

353

Benchmarking van der Waals density functionals with experimental data: potential-energy curves for H2 molecules on Cu(111), (100) and (110) surfaces  

NASA Astrophysics Data System (ADS)

Detailed physisorption data from experiment for the H2 molecule on low-index Cu surfaces challenge theory. Recently, density functional theory (DFT) has been developed to account for nonlocal correlation effects, including van der Waals (dispersion) forces. We show that the functional vdW-DF2 gives a potential-energy curve, potential-well energy levels and difference in lateral corrugation promisingly close to the results obtained by resonant elastic backscattering-diffraction experiments. The backscattering barrier is sensitive to the choice of exchange functional approximation. Further, the DFT-D3 and TS-vdW corrections to traditional DFT formulations are also benchmarked, and deviations are analyzed.

Lee, Kyuho; Berland, Kristian; Yoon, Mina; Andersson, Stig; Schröder, Elsebeth; Hyldgaard, Per; Lundqvist, Bengt I.

2012-10-01

354

Symmetric elastic and spin-flip low-energy collisions of the hydrogen-isotope mesic atoms in the adiabatic hyperspherical approach  

Microsoft Academic Search

The reduced adiabatic hyperspherical (RAHS) basis suggested previously is used to calculate elastic and spin-flip cross sections\\u000a in the processes (a?)F+a ? (a?)F?+a, a=(p, d, t), for collision energies 10?3???102 eV. The rapid convergence of the method is demonstrated: to achieve an accuracy of ?1% in the calculated cross sections,\\u000a it is sufficient to use N?10 of the basis RAHS

D. I. Abramov; V. V. Gusev; L. I. Ponomarev

2004-01-01

355

Elastic and inelastic scattering of [sup 16]O and [sup 18]O ions from [sup 64]Zn at energies near the Coulomb barrier  

Microsoft Academic Search

Coulomb-nuclear interference effects were investigated in the inelastic scattering of [sup 16]O and [sup 18]O by [sup 64]Zn. Measurements of elastic and inelastic angular distributions of [sup 18]O were performed at a laboratory energy of 49 MeV, over the angular range from [theta][sub lab][similar to]30[degree] to 85[degree]. The excitation functions of [sup 16]O and [sup 18]O ions were measured at

S. Salem-Vasconcelos; E. M. Takagui; M. J. Bechara; K. Koide; O. Dietzsch; A. B. N. Jr; H. Takai

1994-01-01

356

High order multipole three-body forces and their contribution to the elastic constants and zero point energy of the rare gas crystals  

Microsoft Academic Search

High order multipole three-body forces are shown to contribute significant amounts to the theoretical values of the elastic constants of the rare gas crystals. Their effect is to make the quantity delta =(C44-C12)\\/C12 slightly more negative than the value obtained using dipole interactions only. Their effect on the harmonic zero point energy is small but of the same order as

I. J. Zucker; M. B. Doran

1972-01-01

357

Available Potential Energy and Exergy in Stratified Fluids  

NASA Astrophysics Data System (ADS)

Lorenz's theory of available potential energy (APE) remains the main framework for studying the atmospheric and oceanic energy cycles. Because the APE generation rate is the volume integral of a thermodynamic efficiency times the local diabatic heating/cooling rate, APE theory is often regarded as an extension of the theory of heat engines. Available energetics in classical thermodynamics, however, usually relies on the concept of exergy and is usually measured relative to a reference-state maximizing entropy at constant energy, whereas APE's reference state minimizes potential energy at constant entropy. This review seeks to shed light on the two concepts; it covers local formulations of available energetics, alternative views of the dynamics/thermodynamics coupling, APE theory and the second law of thermodynamics, APE production/dissipation, extensions to binary fluids, mean/eddy decompositions, APE in incompressible fluids, APE and irreversible turbulent mixing, and the role of mechanical forcing on APE production.

Tailleux, Rémi

2013-01-01

358

Finding reaction paths using the potential energy as reaction coordinate  

NASA Astrophysics Data System (ADS)

The intrinsic reaction coordinate curve (IRC), normally proposed as a representation of a reaction path, is parametrized as a function of the potential energy rather than the arc-length. This change in the parametrization of the curve implies that the values of the energy of the potential energy surface points, where the IRC curve is located, play the role of reaction coordinate. We use Carathéodory's relation to derive in a rigorous manner the proposed parametrization of the IRC path. Since this Carathéodory's relation is the basis of the theory of calculus of variations, then this fact permits to reformulate the IRC model from this mathematical theory. In this mathematical theory, the character of the variational solution (either maximum or minimum) is given through the Weierstrass E-function. As proposed by Crehuet and Bofill [J. Chem. Phys. 122, 234105 (2005)], we use the minimization of the Weierstrass E-function, as a function of the potential energy, to locate an IRC path between two minima from an arbitrary curve on the potential energy surface, and then join these two minima. We also prove, from the analysis of the Weierstrass E-function, the mathematical bases for the algorithms proposed to locate the IRC path. The proposed algorithm is applied to a set of examples. Finally, the algorithm is used to locate a discontinuous, or broken, IRC path, namely, when the path connects two first order saddle points through a valley-ridged inflection point.

Aguilar-Mogas, Antoni; Giménez, Xavier; Bofill, Josep Maria

2008-03-01

359

Finding reaction paths using the potential energy as reaction coordinate.  

PubMed

The intrinsic reaction coordinate curve (IRC), normally proposed as a representation of a reaction path, is parametrized as a function of the potential energy rather than the arc-length. This change in the parametrization of the curve implies that the values of the energy of the potential energy surface points, where the IRC curve is located, play the role of reaction coordinate. We use Caratheodory's relation to derive in a rigorous manner the proposed parametrization of the IRC path. Since this Caratheodory's relation is the basis of the theory of calculus of variations, then this fact permits to reformulate the IRC model from this mathematical theory. In this mathematical theory, the character of the variational solution (either maximum or minimum) is given through the Weierstrass E-function. As proposed by Crehuet and Bofill [J. Chem. Phys. 122, 234105 (2005)], we use the minimization of the Weierstrass E-function, as a function of the potential energy, to locate an IRC path between two minima from an arbitrary curve on the potential energy surface, and then join these two minima. We also prove, from the analysis of the Weierstrass E-function, the mathematical bases for the algorithms proposed to locate the IRC path. The proposed algorithm is applied to a set of examples. Finally, the algorithm is used to locate a discontinuous, or broken, IRC path, namely, when the path connects two first order saddle points through a valley-ridged inflection point. PMID:18345872

Aguilar-Mogas, Antoni; Giménez, Xavier; Bofill, Josep Maria

2008-03-14

360

Hydroelastic response and energy harvesting potential of flexible piezoelectric beams in viscous flow  

NASA Astrophysics Data System (ADS)

Electroactive polymers such as piezoelectric elements are able to generate electric potential differences from induced mechanical deformations. They can be used to build devices to harvest ambient energy from natural flow-induced deformations, e.g., as flapping flags subject to flowing wind or artificial seaweed subject to waves or underwater currents. The objectives of this study are to (1) investigate the transient hydroelastic response and energy harvesting potential of flexible piezoelectric beams fluttering in incompressible, viscous flow, and (2) identify critical non-dimensional parameters that govern the response of piezoelectric beams fluttering in viscous flow. The fluid-structure interaction response is simulated using an immersed boundary approach coupled with a finite volume solver for incompressible, viscous flow. The effects of large beam deformation, membrane tension, and coupled electromechanical responses are all considered. Validation studies are shown for the motion of a flexible filament in uniform flow, and for a piezoelectric beam subject to base vibration. The predicted flutter velocities and frequencies also compared well with published experimental and numerical data over a range of Reynolds numbers for varying fluid and solid combinations. The results showed that for a heavy beam in a light fluid (i.e., high ?? regime), flutter incepts at a lower critical speed with a lower reduced frequency than for a light beam in a heavy fluid (i.e., low ?? regime). In the high ?? regime, flutter develops at the second mode and is only realized when the fluid inertial forces are in balance with the solid elastic restoring forces, which leads to large amplitude oscillations and complex wake patterns; the flutter speed is practically independent of the Reynolds number (Re) and solid to fluid mass ratio (??), because the response is dominated by the solid inertial forces. In the low ?? regime, fluid inertial forces dominate, flutter develops at higher modes and is only realized when the solid inertial forces are proportioned to the solid elastic restoring forces; the flutter speed depends on both Re and ??, and viscous force and beam tension effects tend to delay flutter and reduce vibration amplitudes, leading to thinner, more simplified wake patterns. The results demonstrate that energy extraction via fluttering piezoelectric beams is possible. The overall efficiency was observed to be influenced by the piezoelectric circuit resistance, which is known to be directly related to the square of the piezoelectric coupling factor. The results show that the maximum strain limit of piezoelectrics may be exceeded, and hence careful optimization of the material and geometry is recommended to maximize the energy capture for a given range of expected flow conditions while satisfying safety and reliability requirements.

Akcabay, Deniz Tolga; Young, Yin Lu

2012-05-01

361

Elastic Constants from Molecular Dynamics in the Presence of Microstructure  

NASA Astrophysics Data System (ADS)

We calculate second (and third) order elastic constants in the presence of twin and tweed-like microstructure in martensitic and other structural phase transitions using fluctuation formulas and embedded atom method (EAM) and modified (MEAM) potentials in molecular dynamics simulations. We illustrate the results on NiAl alloys. This procedure allows us to study and distinguish the effects of microstructure such as twin or tweed on various elastic constants. In addition, it provides direct microscopic input to determine the expansion coefficients in the mesoscopic Ginzburg-Landau free energy description, which can then be validated against measured elastic constants in a single crystal of NiAl. The procedure can be readily applied to other alloys of interest, e.g. AuCd and FePd with appropriate choice of MEAM potentials.

Srinivasan, S. G.; Dimitrov, D. A.; Lookman, T.; Saxena, A.; Albers, R. C.; Bishop, A. R.

2000-03-01

362

Reference pressure changes and available potential energy in isobaric coordinates  

NASA Technical Reports Server (NTRS)

A formulation of the available potential energy (APE) equation in isobaric coordinates which alleviates the need for computing temporal derivatives of reference pressure and describes how work done relates to changes in the APE of a limited region is presented. The APE budget equation possesses terms analogous to those in Johnson's (1970) isentropic version. It is shown that APE changes result from either mechanical work inside the domain or an exchange of energy via boundary processes with the surrounding environment.

Robertson, F. R.

1985-01-01

363

Potential structural material problems in a hydrogen energy system  

NASA Technical Reports Server (NTRS)

Potential structural material problems that may be encountered in the three components of a hydrogen energy system - production, transmission/storage, and utilization - have been identified. Hydrogen embrittlement, corrosion, oxidation, and erosion may occur during the production of hydrogen. Hydrogen embrittlement is of major concern during both transmission and utilization of hydrogen. Specific materials research and development programs necessary to support a hydrogen energy system are described. An awareness of probable shortages of strategic materials has been maintained in these suggested programs.

Gray, H. R.; Nelson, H. G.; Johnson, R. E.; Mcpherson, W. B.; Howard, F. S.; Swisher, J. H.

1976-01-01

364

Assessment of wind energy potential in Gaza Strip  

Microsoft Academic Search

The analysis of collected wind data at two sites in the Gaza Strip, namely, Gaza City and Gaza International Airport in Rafah\\u000a city, is presented. The two sites are candidates for remote area wind energy applications. The purpose of this paper is to\\u000a present the results of the assessment of wind energy potential in the Gaza Strip in order to

Juma Yousuf Alaydi

2011-01-01

365

Structure and potential energy surface of K +·CX 2  

Microsoft Academic Search

The potential energy surface of K+·CO2 and K+·CS2 complexes are determined at high levels of ab initio theory (CCSD), B3LYP, and MP2 using different basis sets. These calculations predict the existence of three minima for K+·CO2 complex; linear, quadrilateral and Y-shape, and two minima for K+·CS2 complex; bent and Y-shape. In addition, the binding energies, and other thermodynamic quantities are

M. I. Alomari; J. N. Dawoud

2010-01-01

366

Potential-Energy Surfaces for Heavy-Ion Collisions  

Microsoft Academic Search

We calculate the nuclear potential energy of deformation for the collision of two heavy nuclei by means of a macroscopic-microscopic method. The nuclear macroscopic energy is calculated in terms of a double volume integral of a Yukawa function, and the microscopic shell and pairing corrections are calculated by use of Strutinsky's method from the single-particle levels of a realistic diffuse-surface

J. R. Nix; A. J. Sierk

1974-01-01

367

Potential structural material problems in a hydrogen energy system  

NASA Technical Reports Server (NTRS)

Potential structural material problems that may be encountered in the three components of a hydrogen energy system - production, transmission/storage, and utilization - were identified. Hydrogen embrittlement, corrosion, oxidation, and erosion may occur during the production of hydrogen. Hydrogen embrittlement is of major concern during both transmission and utilization of hydrogen. Specific materials research and development programs necessary to support a hydrogen energy system are described.

Gray, H. R.; Nelson, H. G.; Johnson, R. E.; Mcpherson, B.; Howard, F. S.; Swisher, J. H.

1975-01-01

368

Cadmium tolerance and accumulation in eight potential energy crops  

Microsoft Academic Search

The production of energy crops that can be used for biodiesel production is a sustainable approach for the removal of metal pollutants by phytoremediation. This study investigated the cadmium (Cd) accumulation and tolerance of eight potential energy crops. After growth for 28 days in substrates containing 0, 50, 100 or 200 mg Cd·kg?1, seedlings were evaluated for growth parameters, chlorophyll content, chlorophyll

Gangrong Shi; Qingsheng Cai

2009-01-01

369

Nonlinear elasticity of biological tissues with statistical fibre orientation.  

PubMed

The elastic strain energy potential for nonlinear fibre-reinforced materials is customarily obtained by superposition of the potentials of the matrix and of each family of fibres. Composites with statistically oriented fibres, such as biological tissues, can be seen as being reinforced by a continuous infinity of fibre families, the orientation of which can be represented by means of a probability density function defined on the unit sphere (i.e. the solid angle). In this case, the superposition procedure gives rise to an integral form of the elastic potential such that the deformation features in the integral, which therefore cannot be calculated a priori. As a consequence, an analytical use of this potential is impossible. In this paper, we implemented this integral form of the elastic potential into a numerical procedure that evaluates the potential, the stress and the elasticity tensor at each deformation step. The numerical integration over the unit sphere is performed by means of the method of spherical designs, in which the result of the integral is approximated by a suitable sum over a discrete subset of the unit sphere. As an example of application, we modelled the collagen fibre distribution in articular cartilage, and used it in simulating displacement-controlled tests: the unconfined compression of a cylindrical sample and the contact problem in the hip joint. PMID:20053655

Federico, Salvatore; Gasser, T Christian

2010-06-01

370

LHC Physics Potential vs. Energy: Considerations for the 2011 Run  

SciTech Connect

Parton luminosities are convenient for estimating how the physics potential of Large Hadron Collider experiments depends on the energy of the proton beams. I quantify the advantage of increasing the beam energy from 3.5 TeV to 4 TeV. I present parton luminosities, ratios of parton luminosities, and contours of fixed parton luminosity for gg, u {bar d}, qq, and gq interactions over the energy range relevant to the Large Hadron Collider, along with example analyses for specific processes. This note extends the analysis presented in Ref. [1]. Full-size figures are available as pdf files at lutece.fnal.gov/PartonLum11/.

Quigg, Chris; /Fermilab /CERN

2011-02-01

371

High elastic modulus polymer electrolytes  

DOEpatents

A polymer that combines high ionic conductivity with the structural properties required for Li electrode stability is useful as a solid phase electrolyte for high energy density, high cycle life batteries that do not suffer from failures due to side reactions and dendrite growth on the Li electrodes, and other potential applications. The polymer electrolyte includes a linear block copolymer having a conductive linear polymer block with a molecular weight of at least 5000 Daltons, a structural linear polymer block with an elastic modulus in excess of 1.times.10.sup.7 Pa and an ionic conductivity of at least 1.times.10.sup.-5 Scm.sup.-1. The electrolyte is made under dry conditions to achieve the noted characteristics.

Balsara, Nitash Pervez; Singh, Mohit; Eitouni, Hany Basam; Gomez, Enrique Daniel

2013-10-22

372

Energy and angular momentum dependence of heavy ion optical potentials  

Microsoft Academic Search

The influence of bombarding energy and angular momentum on the depth and shape of the real part of the optical ion-ion potential is studied in a model which uses oscillator wave functions for the ground states of the interacting nuclei and takes into account the relative motion of the nuclei by a multiplication with a plane wave factor. The calculations

P. G. Zint

1977-01-01

373

Investigation of Wind Energy Potential in Kartalkaya-Bolu, Turkey  

Microsoft Academic Search

In this study, wind characteristics and the wind energy potential of the Kartalkaya skinning center in the west of the Black Sea region of Turkey were analyzed using wind speed data collected during the period from 2000 to 2006. The wind speed distribution curves of the investigated location were obtained by using the Weibull and Rayleigh probability density functions based

Aynur Ucar; Figen Balo

2009-01-01

374

Solar Energy Potential of Clusters on Sloped Terrains  

Microsoft Academic Search

Rapid worldwide urbanizations are demanding more land for construction and many cities surrounded by hills have started to expand onto neighbouring slopes. Whilst building on flat terrains is well investigated and documented, there is sill limited published research on the potential of energy conscious building on sloped terrain. The present study is part of a long-term research project which aims

PATRICIA VELOSO DA VEIGA; MOHAMED GADI

375

A highly accurate potential energy curve for the mercury dimer  

NASA Astrophysics Data System (ADS)

The potential energy curve of the electronic ground state of the mercury dimer based on CCSD(T) calculations at the complete basis set (CBS) limit, including corrections for the full triples ?T and explicit spin-orbit (SO) interactions at the CCSD(T) level of theory, is presented. In the far long-range part, the potential energy curve is complemented by symmetry-adapted perturbation theory calculations. Potential curves of an analytically simple, extended Lennard-Jones form are obtained from very accurate fits to the CBS/CCSD(T)+SO and CBS/CCSD(T)+SO+?T data. The Hg2 potential curves yield dissociation energies of De=424/392 cm-1 and equilibrium distances of re=3.650/3.679 A? at the CBS/CCSD(T)+SO and CBS/CCSD(T)+SO+?T levels of theory, respectively. By including perturbative quadruple corrections in our coupled-cluster calculations and corrections from correlating the 4f-core, we arrive at a final dissociation energy of De=405 cm-1, in excellent agreement with the experimentally estimated value of 407 cm-1 by Greif and Hensel. In addition, the rotational and vibrational spectroscopic constants as well as the second virial coefficient B(T) in dependence of the temperature T are calculated and validated against available experimental and theoretical data.

Pahl, Elke; Figgen, Detlev; Thierfelder, Christian; Peterson, Kirk A.; Calvo, Florent; Schwerdtfeger, Peter

2010-03-01

376

Collective potential-energy surfaces in heavy-ion reactions  

Microsoft Academic Search

Multidimensional potential-energy surfaces have been calculated for heavy-ion reactions as a function of separation (or elongation), neck-formation and mass-asymmetry collective degrees of freedom. The reactions Ar + Ag, Kr + Cu, Kr + Bi and Xe + Bi, of current interest, are considered as examples. The effects of the entrance channel asymmetry and the total charge and angular momentum of

O. Zohni; M. Blann

1978-01-01

377

Teaching Field Concept and Potential Energy at A-Level.  

ERIC Educational Resources Information Center

Argues for a greater emphasis on the reality of fields in electronics and gravitation instruction. Advocates that the potential energy in a system be regarded as stored in the field rather than in the material bodies of the system. Provides a rationale and examples for this position. (ML)

Poon, C. H.

1986-01-01

378

Inverse Problem at Fixed Energy for Finite Range Complex Potentials.  

National Technical Information Service (NTIS)

In the inverse problem of scattering theory, a simple transformation may be used to map the results for a fixed l=0 value of the angular momentum onto similar results at fixed energy concerning a finite-range potential. This property is applied to non-sel...

P. Sergent C. Coudray

1977-01-01

379

Potential Energy Functions for Transition Metals and Their Aluminides  

NASA Astrophysics Data System (ADS)

Transition metal aluminides have a wide range of potential uses in applications requiring high strength and light weight. Obtaining accurate potential energy functions is the first step in trying to understand the structural and defect properties of these materials. Using the simple Anderson model and ab-initio results as inputs, we are able to derive strong medium- and long-ranged interactions among the transition metal atoms in aluminides. Treating the pseudopotentials as a perturbation, we obtain a complete set of pair potentials for any pair of atoms in the aluminides. These potentials agree well with experiments on the structure of liquid aluminides, predict the correct chemical trends in structural stability, and in most cases reproduce the large structural energy differences that have been demonstrated by ab-initio calculations. The calculated results on the structural energies agree fairly well with the experimental phase diagram and the existing ab-initio results. On the basis of these potentials, we propose an explanation for quasicrystal formation in the aluminides. Four-body angular forces recently developed by Carlsson are used in the molecular dynamics simulation of liquid W to examine the effect of angular forces on the structure and thermodynamic properties of the liquid. We do not find any significant effect of the angular forces as compared with radial interatomic forces. However, the angular forces are much more accurate overall in treating the thermodynamic properties.

Zou, Jun

380

Three-dimensional elastic image registration based on strain energy minimization: application to prostate magnetic resonance imaging.  

PubMed

The use of magnetic resonance (MR) imaging in conjunction with an endorectal coil is currently the clinical standard for the diagnosis of prostate cancer because of the increased sensitivity and specificity of this approach. However, imaging in this manner provides images and spectra of the prostate in the deformed state because of the insertion of the endorectal coil. Such deformation may lead to uncertainties in the localization of prostate cancer during therapy. We propose a novel 3-D elastic registration procedure that is based on the minimization of a physically motivated strain energy function that requires the identification of similar features (points, curves, or surfaces) in the source and target images. The Gauss-Seidel method was used in the numerical implementation of the registration algorithm. The registration procedure was validated on synthetic digital images, MR images from prostate phantom, and MR images obtained on patients. The registration error, assessed by averaging the displacement of a fiducial landmark in the target to its corresponding point in the registered image, was 0.2 ± 0.1 pixels on synthetic images. On the prostate phantom and patient data, the registration errors were 1.0 ± 0.6 pixels (0.6 ± 0.4 mm) and 1.8 ± 0.7 pixels (1.1 ± 0.4 mm), respectively. Registration also improved image similarity (normalized cross-correlation) from 0.72 ± 0.10 to 0.96 ± 0.03 on patient data. Registration results on digital images, phantom, and prostate data in vivo demonstrate that the registration procedure can be used to significantly improve both the accuracy of localized therapies such as brachytherapy or external beam therapy and can be valuable in the longitudinal follow-up of patients after therapy. PMID:20552248

Zhang, Bao; Arola, Dwayne D; Roys, Steve; Gullapalli, Rao P

2011-08-01

381

Elastic proteins: biological roles and mechanical properties.  

PubMed

The term 'elastic protein' applies to many structural proteins with diverse functions and mechanical properties so there is room for confusion about its meaning. Elastic implies the property of elasticity, or the ability to deform reversibly without loss of energy; so elastic proteins should have high resilience. Another meaning for elastic is 'stretchy', or the ability to be deformed to large strains with little force. Thus, elastic proteins should have low stiffness. The combination of high resilience, large strains and low stiffness is characteristic of rubber-like proteins (e.g. resilin and elastin) that function in the storage of elastic-strain energy. Other elastic proteins play very different roles and have very different properties. Collagen fibres provide exceptional energy storage capacity but are not very stretchy. Mussel byssus threads and spider dragline silks are also elastic proteins because, in spite of their considerable strength and stiffness, they are remarkably stretchy. The combination of strength and extensibility, together with low resilience, gives these materials an impressive resistance to fracture (i.e. toughness), a property that allows mussels to survive crashing waves and spiders to build exquisite aerial filters. Given this range of properties and functions, it is probable that elastic proteins will provide a wealth of chemical structures and elastic mechanisms that can be exploited in novel structural materials through biotechnology. PMID:11911769

Gosline, John; Lillie, Margo; Carrington, Emily; Guerette, Paul; Ortlepp, Christine; Savage, Ken

2002-02-28

382

Energy life cycle assessment of rice straw bio-energy derived from potential gasification technologies  

Microsoft Academic Search

To be a viable alternative, a biofuel should provide a net energy gain and be capable of being produced in large quantities without reducing food supplies. Amounts of agricultural waste are produced and require treatment, with rice straw contributing the greatest source of such potential bio-fuel in Taiwan. Through life-cycle accounting, several energy indicators and four potential gasification technologies (PGT)

Je-Lueng Shie; Ching-Yuan Chang; Ci-Syuan Chen; Dai-Gee Shaw; Yi-Hung Chen; Wen-Hui Kuan; Hsiao-Kan Ma

2011-01-01

383

Global Potential of Energy Efficiency Standards and Labeling Programs  

SciTech Connect

This report estimates the global potential reductions in greenhouse gas emissions by 2030 for energy efficiency improvements associated with equipment (appliances, lighting, and HVAC) in buildings by means of energy efficiency standards and labels (EES&L). A consensus has emerged among the world's scientists and many corporate and political leaders regarding the need to address the threat of climate change through emissions mitigation and adaptation. A further consensus has emerged that a central component of these strategies must be focused around energy, which is the primary generator of greenhouse gas emissions. Two important questions result from this consensus: 'what kinds of policies encourage the appropriate transformation to energy efficiency' and 'how much impact can these policies have'? This report aims to contribute to the dialogue surrounding these issues by considering the potential impacts of a single policy type, applied on a global scale. The policy addressed in this report is Energy Efficient Standards and Labeling (EES&L) for energy-consuming equipment, which has now been implemented in over 60 countries. Mandatory energy performance standards are important because they contribute positively to a nation's economy and provide relative certainty about the outcome (both timing and magnitudes). Labels also contribute positively to a nation's economy and importantly increase the awareness of the energy-consuming public. Other policies not analyzed here (utility incentives, tax credits) are complimentary to standards and labels and also contribute in significant ways to reducing greenhouse gas emissions. We believe the analysis reported here to be the first systematic attempt to evaluate the potential of savings from EES&L for all countries and for such a large set of products. The goal of the analysis is to provide an assessment that is sufficiently well-quantified and accurate to allow comparison and integration with other strategies under consideration.

McNeil, Michael A; McNeil, Michael A.; Letschert, Virginie; de la Rue du Can, Stephane

2008-06-15

384

N2(+) bound quartet and sextet state potential energy curves  

NASA Technical Reports Server (NTRS)

The N2(+) potential energies have been determined from a complete active space self-consistent field calculation with active 2s and 2p electrons. A (6s 4p 3d 1f) Gaussian basis set was used together with additional higher angular momentum and diffuse functions. The calculated potential energy curves for the states 4Sigma(mu)(+), 4Pi(g), and 6Sigma(g)(+), for which there are no spectroscopic observations, are presented. The corresponding spectroscopic constants have been determined from a polynomial curve fit to the computed energies near the well minima and are shown. The 6Sigma(g)(+) state is found to be significantly bound, with a minimum at 1.72 A.

Partridge, H.; Bauschlicher, C. W., Jr.; Stallcop, J. R.

1985-01-01

385

How deep is the antinucleon optical potential at FAIR energies  

NASA Astrophysics Data System (ADS)

The key question in the interaction of antinucleons in the nuclear medium concerns the deepness of the antinucleon-nucleus optical potential. In this work we study this task in the framework of the non-linear derivative (NLD) model which describes consistently bulk properties of nuclear matter and Dirac phenomenology of nucleon-nucleus interactions. We apply the NLD model to antinucleon interactions in nuclear matter and find a strong decrease of the vector and scalar self-energies in energy and density and thus a strong suppression of the optical potential at zero momentum and, in particular, at FAIR energies. This is in agreement with available empirical information and, therefore, resolves the issue concerning the incompatibility of G-parity arguments in relativistic mean-field (RMF) models. We conclude the relevance of our results for the future activities at FAIR.

Gaitanos, T.; Kaskulov, M.; Lenske, H.

2011-09-01

386

Global interior eddy available potential energy diagnosed from Argo floats  

NASA Astrophysics Data System (ADS)

By combining all Argo profiles for the period 2002 to present, a cumulative density function is constructed on a 3-D grid of the global ocean. This function quantifies the statistics of isopycnals: time-averaged density, root-mean square of isopycnal displacement, and eddy available potential energy (EAPE). EAPE is the analogue of the eddy kinetic energy, but for the potential energy reservoir. Because it is essentially tied to the spatial structure and magnitude of mesoscale activity, EAPE is an important quantity that should be useful to evaluate eddy resolving/permitting model turbulence and circulation. Among other striking features are the turbulent behavior of Pacific and southern Atlantic Tsuchiya jets and subsurface EAPE maxima in some parts of the ocean, particularly in the Southern Ocean.

Roullet, Guillaume; Capet, Xavier; Maze, Guillaume

2014-03-01

387

Analysis of partial dislocations in wurtzite GaN using gradient elasticity  

Microsoft Academic Search

A non-singular gradient elasticity solution for the dislocation self-energy is employed and compared to previous results for 1\\/6203 partial dislocations fault in wurtzite GaN obtained by empirical potential calculations. Twenty-four previously obtained stable dislocation cores, twelve for each GaN polarity, are considered. It is shown that the gradient elasticity solution can be fitted to the atomistic simulations with good agreement

J. Kioseoglou; G. P. Dimitrakopulos; Ph. Komninou; Th. Karakostas; I. Konstantopoulos; M. Avlonitis; E. C. Aifantis

2006-01-01

388

Elastic properties of apatites  

Microsoft Academic Search

One of the prime motives for studying the elastic properties of the apatites stems from the occurrence of hydroxyapatite, OHAp, in calcified tissue. In this paper the isotropic elastic contents of crystalline apatite solids are determined from measurements of elastic wave velocities through powders under pressure. Once obtained, these elastic constants are used to model the elastic behaviour of a

R. S. Gilmore; J. L. Katz

1982-01-01

389

Quasi-Elastic Transfer Reactions in SULFUR-32 + MOLYBDENUM-92,98,100 and NIOBIUM-93 Systems at Energies Near the Coulomb Barrier.  

NASA Astrophysics Data System (ADS)

Angular distributions of the few-nucleon transfer reactions in ^{32}S + ^{92,98,100}Mo and ^{93}Nb were measured at laboratory energies of 109, 116, and 125 MeV. Beams of ^ {32}S were accelerated by the Stony Brook tandem-linac accelerator. The charge of the projectile -like transfer products was identified by E - Delta E gas telescopes. The mass identification was achieved by measuring the energy and time-of-flight, using Si surface barrier detectors, where the linac RF signals provided master time references. The timing width of the beam was between 150 and 200 ps. Up to three nucleons pickup and four nucleons stripping were observed. The pickup channels are primarily neutron pickup and the stripping channels are dominated by proton stripping which agrees with the Q-matching condition predictions. The elastic scattering data were fitted by the optical model to obtain optical model potential parameters. The transfer angular distributions are bell-shaped. The peak of the angular distribution shifts toward 180 ^circ, in the center-of-mass frame, as energies approach the Coulomb barrier. Distorted-wave Born approximation calculations were performed to compare with the one- and two-nucleon transfer data. Good agreement was seen, particularly at energies below the barrier. The one-nucleon transfer cross sections are among 60 to 70% of the total transfer cross sections. The sum of the total transfer and fusion cross sections made up the total reaction cross sections. Large transfer cross sections were measured in ^{98,100 }Mo and ^{93}Nb targets while small transfer cross sections were measured in ^{92}Mo target, particularly at energies near the barrier. This is consistent with the large sub-barrier fusion enhancement observed in ^{32}S + ^{98,100 }Mo, ^{93}Nb but no enhancement in ^{32}S + ^{92}Mo. The transfer probability for one- and two-nucleon transfer was compared with the DWBA predictions at large reaction distances, d_0 >= 1.6 fm. The transfer probability for one-nucleon transfer is in good agreement with the DWBA calculations. The two -proton transfer probability shows anomalous slope at energies slightly above the barrier. However, there is no slope anomaly for two-proton stripping at energies below the barrier. A sharp change in the slope behaviour for two -proton transfer was observed right at the barrier. For two-neutron transfer, there is no slope anomaly at energies above the barrier which agrees with the neutron transfer systematics. A simple model studied suggests that at these energies, the transfer mechanism should be dominated by the semiclassical picture. The slope anomaly for two-proton transfer at energies above the barrier may be due to the influence of diffractive processes.

Liang, Junjien Felix

390

Momentum potential theory of energy flux carried by momentum fluctuations  

NASA Astrophysics Data System (ADS)

The momentum potential theory of time-stationary fluctuating flows is briefly reviewed and then extended to include energy flux carried by momentum fluctuations. It is shown that the mean (time-averaged) energy flux can be expressed as a linear superposition of mean, turbulent, acoustic and thermal components. A mean energy flux balance relating turbulent, acoustic and thermal energy fluxes only is obtained. For homentropic flows the Cantrell and Hart expression for acoustic intensity is obtained as a special case. Physical and analog interpretations of the mean energy flux balance are presented for the general case. A formal solution of the equation for mean flow of energy due to momentum fluctuations is presented, leading to a definition of local fluctuating dynamical equilibrium of a time-stationary flow and an identification of sources of far field radiated acoustic power. In the Appendix, the momentum potential theory version of Jenvey's partitioning of the stagnation enthalpy into mean, turbulent, acoustic and thermal parts is presented.

Doak, P. E.

1989-05-01

391

A method for measuring coherent elastic neutrino-nucleus scattering at a far off-axis high-energy neutrino beam target  

NASA Astrophysics Data System (ADS)

We present an experimental method for measuring the process of coherent elastic neutrino-nucleus scattering (CENNS). This method uses a detector situated transverse to a high-energy neutrino beam production target. This detector would be sensitive to the low-energy neutrinos arising from decay-at-rest pions in the target. We discuss the physics motivation for making this measurement and outline the predicted backgrounds and sensitivities using this approach. We report a measurement of neutron backgrounds as found in an off-axis surface location of the Fermilab Booster Neutrino Beam (BNB) target. The results indicate that the Fermilab BNB target is a favorable location for a CENNS experiment.

Brice, S. J.; Cooper, R. L.; DeJongh, F.; Empl, A.; Garrison, L. M.; Hime, A.; Hungerford, E.; Kobilarcik, T.; Loer, B.; Mariani, C.; Mocko, M.; Muhrer, G.; Pattie, R.; Pavlovic, Z.; Ramberg, E.; Scholberg, K.; Tayloe, R.; Thornton, R. T.; Yoo, J.; Young, A.

2014-04-01

392

Asymptotic Energy Expansion for Rational Power Polynomial Potentials  

NASA Astrophysics Data System (ADS)

Asymptotic energy expansion method is extended for polynomial potentials having rational powers. New types of recurrence relations are derived for the potentials of the form V (x) = x2n/m + b1xn1/m1 + b2xn2/m2 + ... + bNxnN/mN where n, m, n1, m1, ..., nN, mN are positive integers while coefficients bk ? ?. As in the case of even degree polynomial potentials with integer powers, all the integrals in the expansion can be evaluated analytically in terms of ? functions. With the help of two examples, we demonstrate the usefulness of these expansions in getting analytic insight into the quantum systems having rational power polynomial potentials.

Asiri, Nanayakkara

2012-11-01

393

Ultracold collisions between two light indistinguishable diatomic molecules: Elastic and rotational energy transfer in HD+HD  

NASA Astrophysics Data System (ADS)

A close coupling quantum-mechanical calculation is performed for rotational energy transfer in a HD+HD collision at very low energy, down to the ultracold temperatures: T˜10-8 K. A global six-dimensional H2-H2 potential-energy surface is adopted from a previous work [Boothroyd , J. Chem. Phys.JCPSA60021-960610.1063/1.1405008 116, 666 (2002)]. State-resolved integral cross sections ?ij?i'j'(?kin) of different quantum-mechanical rotational transitions ij?i'j' in the HD molecules and corresponding state-resolved thermal rate coefficients kij?i'j'(T) have been computed. Additionally, for comparison, H2+H2 calculations for a few selected rotational transitions have also been performed. The hydrogen and deuterated hydrogen molecules are treated as rigid rotors in this work. A pronounced isotope effect is identified in the cross sections of these collisions at low and ultracold temperatures.

Sultanov, Renat A.; Guster, Dennis; Adhikari, S. K.

2012-05-01

394

U.S. Building-Sector Energy Efficiency Potential  

SciTech Connect

This paper presents an estimate of the potential for energy efficiency improvements in the U.S. building sector by 2030. The analysis uses the Energy Information Administration's AEO 2007 Reference Case as a business-as-usual (BAU) scenario, and applies percentage savings estimates by end use drawn from several prior efficiency potential studies. These prior studies include the U.S. Department of Energy's Scenarios for a Clean Energy Future (CEF) study and a recent study of natural gas savings potential in New York state. For a few end uses for which savings estimates are not readily available, the LBNL study team compiled technical data to estimate savings percentages and costs of conserved energy. The analysis shows that for electricity use in buildings, approximately one-third of the BAU consumption can be saved at a cost of conserved energy of 2.7 cents/kWh (all values in 2007 dollars), while for natural gas approximately the same percentage savings is possible at a cost of between 2.5 and 6.9 $/million Btu. This cost-effective level of savings results in national annual energy bill savings in 2030 of nearly $170 billion. To achieve these savings, the cumulative capital investment needed between 2010 and 2030 is about $440 billion, which translates to a 2-1/2 year simple payback period, or savings over the life of the measures that are nearly 3.5 times larger than the investment required (i.e., a benefit-cost ratio of 3.5).

Brown, Rich; Borgeson, Sam; Koomey, Jon; Biermayer, Peter

2008-09-30

395

A Mezoscopic Model of Nucleic Acids. Part 2. An Effective Potential Energy Function for DNA  

Microsoft Academic Search

In this study we present an effective Potential of Mean Force (PMF) designed for Lagrangian and Quaternion Molecular Dynamics (LQMD) of DNA. The DNA model is built from pseudoatoms as well as rigid and pseudo-elastic bodies described by a limited number of selected Cartesian and internal degrees of freedom. Phosphate groups, deoxyribose rings and nucleic acid bases are represented by

Maciej Maciejczyk; Witold R. Rudnicki; Bogdan Lesyng

2000-01-01

396

Potential energy profile of colloidal nanoparticles in optical confinement.  

PubMed

An optical bottle method is developed to determine the potential-energy profile of colloidal Rayleigh nanoparticles in an optical trap. The three-dimensional distribution of fluorescent particles in the trap is measured by laser scanning confocal fluorescence microscopy. At sufficiently low concentrations at which interactions between the particles are negligible, the single-particle trapping potential-energy profile is determined from the equilibrium number-density profile by use of the Boltzmann distribution. Fluorescence imaging as well as calculations based on a discrete dipole approximation show that effects due to scattering forces are negligible for polystyrene particles of size less than 10% of the wavelength of the trapping laser, thus justifying the assumption of conservative forces in the equilibrium potential-energy determinations. The new optical bottle method measures the entire two-dimensional trapping-potential profile for an individual nanoparticle without the restriction that only one particle be contained in the trap, thus obviating the need for high laser power. PMID:24321903

Fu, Jinxin; Zhan, Qiwen; Lim, Min Yao; Li, Zhiyuan; Ou-Yang, H Daniel

2013-10-15

397

Elastic constants of a Laves phase compound: C15 NbCr{sub 2}  

SciTech Connect

The single-crystal elastic constants of C15 NbCr{sub 2} have been computed by using a first-principles, self-consistent, full-potential total energy method. From these single-crystal elastic constants the isotropic elastic moduli are calculated using the Voigt and Reuss averages. The calculated values are in fair agreement with the experimental values. The implications of the results are discussed with regards to Poisson`s ratio and the direction dependence of Young`s modulus.

Ormeci, A. [Koc Univ., Istanbul (Turkey)]|[Los Alamos National Lab., NM (United States); Chu, F.; Wills, J.M.; Chen, S.P.; Albers, R.C.; Thoma, D.J.; Mitchell, T.E. [Los Alamos National Lab., NM (United States)

1997-04-01

398

Observation of adsorbate-induced surface states by elastic electron tunneling spectroscopy  

NASA Technical Reports Server (NTRS)

Electronic structure induced by adsorbates at the interface of Al/AlOx/Au tunnel junctions has been observed by elastic electron tunneling spectroscopy. Strong structures appearing in the tunneling spectra above approximately 1 eV after exposure to I, Hg, Bi, and organohalides, have been interpreted in terms of adsorbate-induced surface states. The spectroscopic capabilities of elastic electron tunneling spectroscopy may be useful in the area of chemical detection. In the broader sense, the observation of adsorbate-induced unoccupied electronic states below the vacuum energy, makes elastic electron tunneling spectroscopy a potentially useful technique for the study of surfaces.

Leduc, H. G.; Lambe, J.; Thakoor, A. P.; Khanna, S. K.

1985-01-01

399

Uniqueness for plane crack problems in dipolar gradient elasticity and in couple-stress elasticity  

Microsoft Academic Search

The present work deals with the uniqueness theorem for plane crack problems in solids characterized by dipolar gradient elasticity. The theory of gradient elasticity derives from considerations of microstructure in elastic continua [Mindlin, R.D., 1964. Micro-structure in linear elasticity. Arch. Ration. Mech. Anal. 16, 51–78] and is appropriate to model materials with periodic structure. According to this theory, the strain-energy

C. G. Grentzelou; H. G. Georgiadis

2005-01-01

400

Study of elastic wave propagation in two-phase anisotropic media by numerical modeling of pseudospectral method  

Microsoft Academic Search

When there exists anisotropy in underground media, elastic parameters of the observed coordinate possibly do not coincide\\u000a with that of the natural coordinate. According to the theory that the density of potential energy, dissipating energy is independent\\u000a of the coordinate, the relationship of elastic parameters between two coordinates is derived for two-phase anisotropic media.\\u000a Then, pseudospectral method to solve wave

Yang Liu; Cheng-Chu Li

2000-01-01

401

NVU dynamics. III. Simulating molecules at constant potential energy  

NASA Astrophysics Data System (ADS)

This is the final paper in a series that introduces geodesic molecular dynamics at constant potential energy. This dynamics is entitled NVU dynamics in analogy to standard energy-conserving Newtonian NVE dynamics. In the first two papers [T. S. Ingebrigtsen, S. Toxvaerd, O. J. Heilmann, T. B. Schrøder, and J. C. Dyre, J. Chem. Phys. 135, 104101 (2011); T. S. Ingebrigtsen, S. Toxvaerd, T. B. Schrøder, and J. C. Dyre, ibid. 135, 104102 (2011)], a numerical algorithm for simulating geodesic motion of atomic systems was developed and tested against standard algorithms. The conclusion was that the NVU algorithm has the same desirable properties as the Verlet algorithm for Newtonian NVE dynamics, i.e., it is time-reversible and symplectic. Additionally, it was concluded that NVU dynamics becomes equivalent to NVE dynamics in the thermodynamic limit. In this paper, the NVU algorithm for atomic systems is extended to be able to simulate the geodesic motion of molecules at constant potential energy. We derive an algorithm for simulating rigid bonds and test this algorithm on three different systems: an asymmetric dumbbell model, Lewis-Wahnström o-terphenyl (OTP) and rigid SPC/E water. The rigid bonds introduce additional constraints beyond that of constant potential energy for atomic systems. The rigid-bond NVU algorithm conserves potential energy, bond lengths, and step length for indefinitely long runs. The quantities probed in simulations give results identical to those of Nosé-Hoover NVT dynamics. Since Nosé-Hoover NVT dynamics is known to give results equivalent to those of NVE dynamics, the latter results show that NVU dynamics becomes equivalent to NVE dynamics in the thermodynamic limit also for molecular systems.

Ingebrigtsen, Trond S.; Dyre, Jeppe C.

2012-12-01

402

NVU dynamics. III. Simulating molecules at constant potential energy.  

PubMed

This is the final paper in a series that introduces geodesic molecular dynamics at constant potential energy. This dynamics is entitled NVU dynamics in analogy to standard energy-conserving Newtonian NVE dynamics. In the first two papers [T. S. Ingebrigtsen, S. Toxvaerd, O. J. Heilmann, T. B. Schrøder, and J. C. Dyre, J. Chem. Phys. 135, 104101 (2011); T. S. Ingebrigtsen, S. Toxvaerd, T. B. Schrøder, and J. C. Dyre, ibid. 135, 104102 (2011)], a numerical algorithm for simulating geodesic motion of atomic systems was developed and tested against standard algorithms. The conclusion was that the NVU algorithm has the same desirable properties as the Verlet algorithm for Newtonian NVE dynamics, i.e., it is time-reversible and symplectic. Additionally, it was concluded that NVU dynamics becomes equivalent to NVE dynamics in the thermodynamic limit. In this paper, the NVU algorithm for atomic systems is extended to be able to simulate the geodesic motion of molecules at constant potential energy. We derive an algorithm for simulating rigid bonds and test this algorithm on three different systems: an asymmetric dumbbell model, Lewis-Wahnström o-terphenyl (OTP) and rigid SPC/E water. The rigid bonds introduce additional constraints beyond that of constant potential energy for atomic systems. The rigid-bond NVU algorithm conserves potential energy, bond lengths, and step length for indefinitely long runs. The quantities probed in simulations give results identical to those of Nosé-Hoover NVT dynamics. Since Nose?-Hoover NVT dynamics is known to give results equivalent to those of NVE dynamics, the latter results show that NVU dynamics becomes equivalent to NVE dynamics in the thermodynamic limit also for molecular systems. PMID:23277922

Ingebrigtsen, Trond S; Dyre, Jeppe C

2012-12-28

403

Evaluation of global onshore wind energy potential and generation costs.  

PubMed

In this study, we develop an updated global estimate of onshore wind energy potential using reanalysis wind speed data, along with updated wind turbine technology performance, land suitability factors, cost assumptions, and explicit consideration of transmission distance in the calculation of transmission costs. We find that wind has the potential to supply a significant portion of the world energy needs, although this potential varies substantially by region and with assumptions such as on what types of land can be used to site wind farms. Total global economic wind potential under central assumptions, that is, intermediate between optimistic and pessimistic, is estimated to be approximately 119.5 petawatt hours per year (13.6 TW) at less than 9 cents/kWh. A sensitivity analysis of eight key parameters is presented. Wind potential is sensitive to a number of input parameters, particularly wind speed (varying by -70% to +450% at less than 9 cents/kWh), land suitability (by -55% to +25%), turbine density (by -60% to +80%), and cost and financing options (by -20% to +200%), many of which have important policy implications. As a result of sensitivities studied here we suggest that further research intended to inform wind supply curve development focus not purely on physical science, such as better resolved wind maps, but also on these less well-defined factors, such as land-suitability, that will also have an impact on the long-term role of wind power. PMID:22715929

Zhou, Yuyu; Luckow, Patrick; Smith, Steven J; Clarke, Leon

2012-07-17

404

Role of the Clean Energy Potential for Energy Savings and Air Pollution Control in Turkey  

Microsoft Academic Search

This article begins with a brief review of the technical potential, the regional distribution, and the air pollution effects of all fossil energy sources as well as of all clean and renewable energy sources that could be used in Turkey. Air pollution levels due to fossil fuel consumption are examined. In this context, the role of clean energy sources is

KAM?L KAYGUSUZ; HULUS? KARGI ABDULLAH KAYGUSUZ; A. Kaygusuz

1996-01-01

405

Influences of hydration force and elastic strain energy on the stability of solid film in a very thin solid-on-liquid structure.  

PubMed

Since hydration forces become very strong at short range and are particularly important for determining the magnitude of the adhesion between two surfaces or interaction energy, the influences of the hydration force and elastic strain energy due to hydration-induced layering of liquid molecules close to a solid film surface on the stability of a solid film in a solid-on-liquid (SOL) nanostructure are studied in this paper. The liquid of this thin SOL structure is a kind of water solution. Since the surface forces play an important role in the structure, the total free energy change of SOL structures consists of the changes in the bulk elastic energy within the solid film, the surface energy at the solid-liquid interface and the solid-air interface, and highly nonlinear volumetric component associated with interfacial forces. The critical wavelength of one-dimensional undulation, the critical thickness of the solid film, and the critical thickness of the liquid layer are studied, and the stability regions of the solid film have been determined. Emphasis is placed on calculation of critical values, which are the basis of analyzing the stability of the very thin solid film. PMID:15267410

Yang, C Y; Zhao, Ya-Pu

2004-03-15

406

A global potential energy surface for ArH2  

NASA Technical Reports Server (NTRS)

We describe a simple analytic representation of the ArH2 potential energy surface which well reproduces the results of extensive ab initio electronic structure calculations. The analytic representation smoothly interpolates between the dissociated H2 and strong bonding limits. In the fitting process, emphasis is made on accurately reproducing regions of the potential expected to be important for high temperature (ca. 3000 K) collision processes. Overall, the anisotropy and H2 bond length dependence of the analytic representation well reproduce the input data.

Schwenke, David W.; Walch, Stephen P.; Taylor, Peter R.

1992-01-01

407

A global potential energy surface for ArH2  

NASA Technical Reports Server (NTRS)

We describe a simple analytic representation of the ArH2 potential energy surface which well reproduces the results of extensive ab initio electronic structure calculations. The analytic representation smoothly interpolates between the dissociated H2 and strong bonding limits. In the fitting process, emphasis is made on accurately reproducing regions of the potential expected to be important for high temperature (ca. 3000 K) collision processes. Overall, the anisotropy and H2 bond length dependence of the analytic representation well reproduce the input data.

Schwenke, David W.; Walch, Stephen P.; Taylor, Peter R.

1993-01-01

408

PBS Learning Media: Investigating Kinetic and Potential Energy  

NSDL National Science Digital Library

In this 3-5 day multimedia module, students explore concepts of kinetic, potential, and total energy within different types of systems. Watch a video of engineers who recreate a medieval trebuchet (using only 14th century technology) and an animation of energy transformation in a roller coaster. Play with a digital mass-and-spring model and a projectile simulator. Finally, students will use computational reasoning in a hands-on golf ball activity. This lesson was designed to engage multiple sensory paths and styles of learning through video, interactive simulation, animations, lab activities, and informative text.

2013-06-06

409

Bifurcations on Potential Energy Surfaces of Organic Reactions  

PubMed Central

A single transition state may lead to multiple intermediates or products if there is a post-transition state reaction path bifurcation. These bifurcations arise when there are sequential transition states with no intervening energy minimum. For such systems, the shape of the potential energy surface and dynamic effects control selectivity rather than transition state energetics. This minireview covers recent investigations of organic reactions exhibiting reaction pathway bifurcations. Such phenomena are surprisingly general and affect experimental observables such as kinetic isotope effects and product distributions.

Ess, Daniel H.; Wheeler, Steven E.; Iafe, Robert G.; Xu, Lai; Celebi-Olcum, Nihan; Houk, K. N.

2009-01-01

410

Quintom dark energy models with nearly flat potentials  

SciTech Connect

We examine quintom dark energy models, produced by the combined consideration of a canonical and a phantom field, with nearly flat potentials and dark energy equation-of-state parameter w{sub DE} close to -1. We find that all such models converge to a single expression for w{sub DE}(z), depending only on the initial field values and their derivatives. We show that this quintom paradigm allows for a description of the transition through -1 in the near cosmological past. In addition, we provide the necessary conditions for the determination of the direction of the -1 crossing.

Setare, M. R.; Saridakis, E. N. [Department of Science, Payame Noor University, Bijar (Iran, Islamic Republic of); Department of Physics, University of Athens, GR-15771 Athens (Greece)

2009-02-15

411

Potential for luminosity improvement for low-energy RHIC operation  

SciTech Connect

At the Brookhaven National Laboratory, a physics program, motivated by the search of the QCD phase transition critical point, requires operation of the Relativistic Heavy Ion Collider (RHIC) with heavy ions at very low beam energies corresponding to 2.5-20 GeV/n. Several physics runs were already successfully performed at these low energies. However, the luminosity is very low at lowest energies of interest (< 10 GeV/n) limited by the intra-beam scattering and space-charge, as well as by machine nonlinearities. At these low energies, electron cooling could be very effective in counteracting luminosity degradation due to the IBS, while it is less effective against other limitations. Overall potential luminosity improvement for low-energy RHIC operation from cooling is summarized for various energies, taking into account all these limitations as well as beam lifetime measured during the low-energy RHIC runs. We also explore a possibility of further luminosity improvement under the space-charge limitation.

Fedotov A. V.

2012-05-20

412

Forward pmacr d elastic scattering and total spin-dependent pmacr d cross sections at intermediate energies  

Microsoft Academic Search

Spin-dependent total pmacr d cross sections are considered using the optical theorem. For this aim the full spin dependence of the forward pmacr d elastic scattering amplitude is considered in a model independent way. The single-scattering approximation is used to relate this amplitude to the elementary amplitudes of pmacr p and pmacr n scattering and the deuteron form factor. A

Yu. N. Uzikov; J. Haidenbauer

2009-01-01

413

Accurate global potential energy surface for the H + OH+ collision  

NASA Astrophysics Data System (ADS)

We mapped the global three-dimensional potential energy surface (3D-PES) of the water cation at the MRCI/aug-cc-pV5Z including the basis set superposition (BSSE) correction. This PES covers the molecular region and the long ranges close to the H + OH+(X3?-), the O + H2+(X2?g+), and the hydrogen exchange channels. The quality of the PES is checked after comparison to previous experimental and theoretical results of the spectroscopic constants of H2O+(tilde X2B1) and of the diatomic fragments, the vibronic spectrum, the dissociation energy, and the barrier to linearity for H2O+(tilde X2B1). Our data nicely approach those measured and computed previously. The long range parts reproduce quite well the diatomic potentials. In whole, a good agreement is found, which validates our 3D-PES.

Gannouni, M. A.; Jaidane, N. E.; Halvick, P.; Stoecklin, T.; Hochlaf, M.

2014-05-01

414

Accurate global potential energy surface for the H + OH(+) collision.  

PubMed

We mapped the global three-dimensional potential energy surface (3D-PES) of the water cation at the MRCI/aug-cc-pV5Z including the basis set superposition (BSSE) correction. This PES covers the molecular region and the long ranges close to the H + OH(+)(X(3)?(-)), the O + H2 (+)(X(2)?g (+)), and the hydrogen exchange channels. The quality of the PES is checked after comparison to previous experimental and theoretical results of the spectroscopic constants of H2O(+)([Formula: see text](2)B1) and of the diatomic fragments, the vibronic spectrum, the dissociation energy, and the barrier to linearity for H2O(+)([Formula: see text](2)B1). Our data nicely approach those measured and computed previously. The long range parts reproduce quite well the diatomic potentials. In whole, a good agreement is found, which validates our 3D-PES. PMID:24832269

Gannouni, M A; Jaidane, N E; Halvick, P; Stoecklin, T; Hochlaf, M

2014-05-14

415

Theoretical characterization of the potential energy surface for NH + NO  

NASA Technical Reports Server (NTRS)

The potential energy surface for NH + NO was characterized using complete active space self-consistent field (CASSCF) gradient calculation to determine the stationary point geometries and frequencies followed by CASSCF/internally contracted configuration interaction calculations to refine the energetics. The present results are in qualitative accord with the BAC-MP4 calculations, but there are differences as large as 8 kcal/mol in the detailed energetics.

Walch, Stephen P.

1993-01-01

416

MCSCF potential energy surface for photodissociation of formaldehyde  

NASA Technical Reports Server (NTRS)

The ground state potential energy surface for the dissociation of formaldehyde (H2CO to H2 and CO) is calculated with the ab initio MCSCF method with an extended (4-31G) basis set. The location, barrier height, and force constants of the transition state are determined, and the normal coordinate analysis is carried out. The calculated barrier height is 4.5 eV. Based on the calculated quantities, the detailed mechanism of the photochemical dissociation is discussed.

Jaffe, R. L.; Morokuma, K.

1976-01-01

417

Spectroscopic constants and potential energy curves of RhH +  

NASA Astrophysics Data System (ADS)

Spectroscopic constants and potential energy curves of 14 electronic states of RhH + are computed. Several spectroscopic transitions are predicted in the IR-UV region none of which is observed. Our computed ground state De of the X2? state of RhH + [2.07 eV] is in good agreement with the experimental value deduced by Elkind and Armentrout [1.91 ± 0.1 eV].

Das, Kalyan K.; Balasubramanian, K.

1991-05-01

418

Potential energy surfaces for RhH sub 2 sup +  

Microsoft Academic Search

Complete active space multiconfiguration self-consistent-field (CASSCF) calculations followed by multireference singles-plus-doubles configuration interactions (MRSDCI) have been carried out on 12 electronic states of RhH{sup +}â. The bending potential energy surfaces of RhH{sup +}â reveal that the a³F ground state of Rh{sup +} forms a complex with Hâ with a geometry of r{sub e} = 1.737 â«, η{sub e} = 27°,

K. K. Das; K. Balasubramanian

1991-01-01

419

Potential energy surfaces describing ion complexes containing molecular hydrogen  

Microsoft Academic Search

High-level abinitio molecular orbital calculations have been carried out to describe the potential energy surfaces for a series of systems corresponding formally to dimer ions of molecular hydrogen with an inert-gas atom or a first- or second-row hydride [X???H2]˙ +, where X=He, Ne, Ar, Kr, HF, HCl, H2O, H2S, NH3, and PH3. Of the [XH2]˙ + ion complexes, [Ne???H2]˙ +,

Josef Ischtwan; Brian J. Smith; Michael A. Collins; Leo Radom

1992-01-01

420

Ab initio potential energy surfaces for SiH 2  

Microsoft Academic Search

Potential surfaces for the ion SiH 2 have been calculated by an ab initio configuration interaction method. Contour diagrams are presented for the [Xtilde]A1 and ÃB1 surfaces and show that in each case the entrance valley is separated from the equilibrium configuration by a substantial energy barrier. For collinear geometries, however, there is only a very small activation barrier in

David M. Hirst; Martyn F. Guest

1986-01-01

421

Ab initio potential energy surfaces for SiH 2  

Microsoft Academic Search

Potential surfaces for the ion SiH+2 have been calculated by an ab initio configuration interaction method. Contour diagrams are presented for the &(X)tilde;2A1 and Ã2B1 surfaces and show that in each case the entrance valley is separated from the equilibrium configuration by a substantial energy barrier. For collinear geometries, however, there is only a very small activation barrier in addition

David M. Hirst; Martyn F. Guest

1986-01-01

422

Martensitic textures: Multiscale consequences of elastic compatibility  

NASA Astrophysics Data System (ADS)

We show that a free energy entirely in the order-parameter strain variable(s), rather than the displacement field, provides a unified understanding of martensitic textures. We use compatibility equations, linking the strain tensor components in the bulk and at interfaces, that induce anisotropic order-parameter strain interactions. These two long-range bulk/interface potentials, together with local compositional fluctuations, drive the formation of global elastic textures. Relaxational simulations show the spontaneous formation (and evolution under stress/temperature quenches) of equal width parallel twins, branched twins, and tweed, including characteristic scaling of twin width with twin length.

Shenoy, S. R.; Lookman, T.; Saxena, A.; Bishop, A. R.

1999-11-01

423

Nuclear momentum distribution and potential energy surface in hexagonal ice  

NASA Astrophysics Data System (ADS)

The proton momentum distribution in ice Ih has been recently measured by deep inelastic neutron scattering and calculated from open path integral Car-Parrinello simulation. Here we report a detailed investigation of the relation between momentum distribution and potential energy surface based on both experiment and simulation results. The potential experienced by the proton is largely harmonic and characterized by 3 principal frequencies, which can be associated to weighted averages of phonon frequencies via lattice dynamics calculations. This approach also allows us to examine the importance of quantum effects on the dynamics of the oxygen nuclei close to the melting temperature. Finally we quantify the anharmonicity that is present in the potential acting on the protons.

Lin, Lin; Morrone, Joseph; Car, Roberto; Parrinello, Michele

2011-03-01

424

Evaluation of Global Onshore Wind Energy Potential and Generation Costs  

SciTech Connect

In this study, we develop an updated global estimate of onshore wind energy potential using reanalysis wind speed data, along with updated wind turbine technology performance and cost assumptions as well as explicit consideration of transmission distance in the calculation of transmission costs. We find that wind has the potential to supply a significant portion of world energy needs, although this potential varies substantially by region as well as with assumptions such as on what types of land can be used to site wind farms. Total global wind potential under central assumptions is estimated to be approximately 89 petawatt hours per year at less than 9 cents/kWh with substantial regional variations. One limitation of global wind analyses is that the resolution of current global wind speed reanalysis data can result in an underestimate of high wind areas. A sensitivity analysis of eight key parameters is presented. Wind potential is sensitive to a number of input parameters, particularly those related to land suitability and turbine density as well as cost and financing assumptions which have important policy implications. Transmission cost has a relatively small impact on total wind costs, changing the potential at a given cost by 20-30%. As a result of sensitivities studied here we suggest that further research intended to inform wind supply curve development focus not purely on physical science, such as better resolved wind maps, but also on these less well-defined factors, such as land-suitability, that will also have an impact on the long-term role of wind power.

Zhou, Yuyu; Luckow, Patrick; Smith, Steven J.; Clarke, Leon E.

2012-06-20

425

Market Potential for Non-electric Applications of Nuclear Energy  

SciTech Connect

The paper presents results of a recent IAEA study to assess the market potential for non-electric applications of nuclear energy in the near (before 2020) and long term (2020-2050). The applications covered are district heating, desalination, industrial heat supply, ship propulsion, energy supply for spacecraft, and, to a lesser extent, 'innovative' applications such as hydrogen production, coal gasification, etc. While technical details are covered only briefly, emphasis is placed on economics and other factors that may promote or hinder the penetration of nuclear options in the markets for non-electric energy services. The study makes a distinction between the market size (demand for a given service) and the market potential for nuclear penetration (which may be smaller because of technical or non-technical constraints). Near-term nuclear prospects are assessed on the basis of on-going projects in the final stages of design or under construction. For the long term, use has been made of a qualitative scale ranging from 0 to 2 for five critical areas: market structure, demand pressure, technical basis, economic competitiveness, and public acceptance. The paper presents the resulting evaluation of long-term prospects for nuclear energy entering into non-electric markets. (authors)

Konishi, T.; Kononov, S.; Kupitz, J.; McDonald, A.; Rogner, H.H. [International Atomic Energy Agency (IAEA), Wagramer Strasse 5, Vienna (Austria); Nisan, S. [Commissariat a l'energie atomique (CEA), CEA/CEN Cadarache, F-13108 Saint Paul-lez-Durance (France)

2002-07-01

426

Data Network Equipment Energy Use and Savings Potential in Buildings  

SciTech Connect

Network connectivity has become nearly ubiquitous, and the energy use of the equipment required for this connectivity is growing. Network equipment consists of devices that primarily switch and route Internet Protocol (IP) packets from a source to a destination, and this category specifically excludes edge devices like PCs, servers and other sources and sinks of IP traffic. This paper presents the results of a study of network equipment energy use and includes case studies of networks in a campus, a medium commercial building, and a typical home. The total energy use of network equipment is the product of the stock of equipment in use, the power of each device, and their usage patterns. This information was gathered from market research reports, broadband market penetration studies, field metering, and interviews with network administrators and service providers. We estimate that network equipment in the USA used 18 TWh, or about 1percent of building electricity, in 2008 and that consumption is expected to grow at roughly 6percent per year to 23 TWh in 2012; world usage in 2008 was 51 TWh. This study shows that office building network switches and residential equipment are the two largest categories of energy use consuming 40percent and 30percent of the total respectively. We estimate potential energy savings for different scenarios using forecasts of equipment stock and energy use, and savings estimates range from 20percent to 50percent based on full market penetration of efficient technologies.

Lanzisera, Steven; Nordman, Bruce; Brown, Richard E.

2010-06-09

427

Mashreq Arab interconnected power system potential for economic energy trading  

SciTech Connect

The Mashreq Arab countries covered in this study are Bahrain, Egypt, Jordan, Lebanon, Oman, Qatar, Saudi Arabia, Syria, the United Arab Emirates, and Yemen. A feasibility study for the interconnection of the electrical networks of the Mashreq Arab countries, sponsored by the Arab Fund, was completed in June 1992. Each country is served by one utility except Saudi Arabia, which is served by four major utilities and some smaller utilities serving remote towns and small load centers. The major utilities are the Saudi consolidated electric Company in the Eastern Province (SCECO East), SCECO Center, SCECO West, and SCECO South. These are the ones considered in this study. The Mashreq Arab region has a considerable mix of energy resources. Egypt and Syria have some limited amounts of hydropower resources, and the Arabian Gulf region is abundant in fossil fuel reserves. Owing to the differences in energy production costs, a potential exists for substantial energy trading between electric utilities in the region. The major objective of this project is to study the feasibility of electric energy trading between the Mashreq Arab countries. The basis, assumptions, and methodologies on which this energy trading study is based relate to the results and conclusions arising out of the previous study, power plant characteristics and costs, assumptions on economic parameters, rules for economy energy exchange, etc. This paper presents the basis, methodology, and major findings of the study.

Al-Shehri, A.M.; El-Amin, I.M.; Opoku, G.; Al-Baiyat, S.A.; Zedan, F.M.

1994-12-01

428

Market potential for optical fiber sensors in the energy sector  

NASA Astrophysics Data System (ADS)

For a long time electric power was taken as a natural unlimited resource. With globalisation the demand for energy has risen. This has brought rising prices for fossil fuels, as well as a diversification of power generation. Besides conventional fossil, nuclear plants are coming up again. Renewable energy sources are gaining importance resulting in recent boom of wind energy plants. In the past reliability and availability and an extremely long lifetime were of paramount importance. Today this has been added by cost, due to the global competition and the high fuel costs. New designs of power components have increased efficiency using lesser material. Higher efficiency causes inevitably higher stress on the materials, of which the machines are built. As a reduction of lifetime is not acceptable and maintenance costs are expected to be at a minimum, condition monitoring systems are going to being used now. This offers potentials for fibre optic sensor application.

Bosselmann, T.

2007-07-01

429

Rubber Balls and Conservation of Energy: A Lesson on Potential and Kinetic Energy  

NSDL National Science Digital Library

This teaching resource was developed by a K-12 science teacher in the American Physiologycal Society's 2006 Frontiers in Physiology Program. For more information on this program, please visit www.frontiersinphys.org. The purpose of this lesson is to teach students about how bouncy rubber balls can be used to demonstrate the concepts of kinetic and potential energy. The topics of kinetic and potential energy should be previously covered or introduced. Upon completion of this activity, students will be able to calculate the energy lost between bounces and account for where the missing energy has gone.

William G Mahl (Seymour Middle School)

2006-08-01

430

Threshold anomaly in the elastic scattering of {sup 6}He on {sup 209}Bi  

SciTech Connect

The energy dependence of the optical potential for the elastic scattering of {sup 6}He on {sup 209}Bi at near and subbarrier energies is studied. Elastic angular distributions and the reaction cross section were simultaneously fitted by performing some modifications in the ECIS code. A phenomenological optical model potential with the Woods-Saxon form was used. There are signatures that the so-called breakup threshold anomaly (BTA) is present in this system having a halo projectile {sup 6}He, as it had been found earlier for systems involving stable weakly bound nuclei.

Garcia, A. R.; Padron, I. [Centro de Aplicaciones Tecnologicas y Desarrollo Nuclear (CEADEN), Playa, Ciudad de la Habana (Cuba); Lubian, J.; Gomes, P. R. S.; Lacerda, T.; Garcia, V. N. [Instituto de Fisica, Universidade Federal Fluminense, Av. Litoranea s/n, Gragoata, Niteroi, R.J., 24210-340 (Brazil); Camacho, A. Gomez; Aguilera, E. F. [Departamento del Acelerador, Instituto Nacional de Investigaciones Nucleares, Apartado Postal 18-1027, C.P. 11801, Mexico, D.F. (Mexico)

2007-12-15

431

On boundary potential energies in deformational and configurational mechanics  

NASA Astrophysics Data System (ADS)

This contribution deals with the implications of boundary potential energies, i.e. in short surface, curve and point potentials, on deformational and configurational mechanics. Within the realm of deformational mechanics the surface/curve potentials are allowed in the most general case to depend on the deformation, the surface/curve deformation gradient and the spatial surface normal/curve tangent and are parametrised in the material placement and the material surface normal/curve tangent. The point potentials depend on the deformation and are parametrised in the material placement. From the configurational mechanics perspective the roles of fields and parametrisations are reversed. By considering variational arguments based on the kinematics of deforming surfaces/curves, in particular the relevant surface/curve stresses and distributed forces contributing to (localized) deformational and configurational force balances at surfaces/curves/points, which extend the common traction boundary conditions, are derived. Thereby, dissipative distributed configurational forces that are energetically conjugate to configurational changes are introduced as definitions. The (localized) force balances at surfaces/curves/points together with the contributing stresses and distributed forces within deformational and configurational mechanics display an intriguing duality. The resulting dissipative configurational tractions at the boundary are exemplified for some illustrative cases of boundary potentials.

Steinmann, Paul

432

Potentials 'R'Us web-server for protein energy estimations with coarse-grained knowledge-based potentials  

PubMed Central

Background Knowledge-based potentials have been widely used in the last 20 years for fold recognition, protein structure prediction from amino acid sequence, ligand binding, protein design, and many other purposes. However generally these are not readily accessible online. Results Our new knowledge-based potential server makes available many of these potentials for easy use to automatically compute the energies of protein structures or models supplied. Our web server for protein energy estimation uses four-body potentials, short-range potentials, and 23 different two-body potentials. Users can select potentials according to their needs and preferences. Files containing the coordinates of protein atoms in the PDB format can be uploaded as input. The results will be returned to the user's email address. Conclusions Our Potentials 'R'Us server is an easily accessible, freely available tool with a web interface that collects all existing and future protein coarse-grained potentials and computes energies of multiple structural models.

2010-01-01

433

Onshore wind energy potential over Iberia: present and future projections  

NASA Astrophysics Data System (ADS)

Onshore grid-connected wind power generation has been explored for more than three decades in the Iberian Peninsula. Further, increasing attention has been devoted to renewable energy sources in a climate change context. While advantages of wind energy are widely recognized, its distribution is not spatially homogeneous and not uniform throughout the year. Hence, understanding these spatial-temporal distributions is critical in power system planning. The present study aims at assessing the potential power output estimated from 10 m wind components simulated by a regional climate model (CCLM), driven by ERA40 reanalysis. Datasets are available on a grid with a high spatial resolution (approximately 20 km) and over a 40-yr period (1961-2000). Furthermore, several target sites, located in areas with high installed wind generation capacity, are selected for local-to-regional scale assessments. The results show that potential wind power is higher over northern Iberia, mostly in Cantabria and Galicia, while Andalucía and Cataluña record the lowest values. With respect to the intra-annual variability, summer is by far the season with the lowest potential energy outputs. Furthermore, the inter-annual variability reveals an overall downward long-term trend over the 40-yr period, particularly in the winter time series. A CCLM transient experiment, forced by the SRES A1B emission scenario, is also discussed for a future period (2041-2070), after a model validation/calibration process (bias corrections). Significant changes in the wind power potential are projected for the future throughout Iberia, but their magnitude largely depends on the locations. This work was partially supported by FEDER (Fundo Europeu de Desenvolvimento Regional) funds through the COMPETE (Programa Operacional Factores de Competitividade) and by national funds through FCT (Fundação para a Ciência e a Tecnologia, Portugal) under project STORMEx FCOMP-01-0124-FEDER- 019524 (PTDC/AAC-CLI/121339/2010).

Rochinha, Carlos A.; Santos, João A.; Liberato, Margarida L. R.; Pinto, Joaquim G.

2014-05-01

434

Electron-impact rotationally elastic total cross sections for H{sub 2}CO and HCOOH over a wide range of incident energy (0.01-2000 eV)  

SciTech Connect

This paper reports computational results of the total cross sections for electron impact on H{sub 2}CO and HCOOH over a wide range of electron impact energies from 0.01 eV to 2 keV. The total cross section is presented as sum of the elastic and electronic excitation cross sections for incident energies. The calculation uses two different methodologies, below the ionization threshold of the target the cross section is calculated using the UK molecular R-matrix code through the Quantemol-N software package while cross sections at higher energies are evaluated using the spherical complex optical potential formalism. The two methods are found to be consistent at the transition energy ({approx}15 eV). The present results are, in general, found to be in good agreement with previous experimental and theoretical results (wherever available) and, thus, the present results can serve as a benchmark for the cross section over a wide range of energy.

Vinodkumar, Minaxi [V P and R P T P Science College, Vallabh Vidyanagar 388 120, Gujarat (India); Bhutadia, Harshad [Government Engineering College, Patan 384265, Gujarat (India); Antony, Bobby [Department of Applied Physics, Indian School of Mines, Dhanbad JH-826004 (India); Mason, Nigel [Department of Physics and Astronomy, Open University, Milton Keynes MK7 6AA (United Kingdom)

2011-11-15

435

Energy surface, chemical potentials, Kohn-Sham energies in spin-polarized density functional theory.  

PubMed

On the basis of the zero-temperature grand canonical ensemble generalization of the energy E[N,N(s),v,B] for fractional particle N and spin N(s) numbers, the energy surface over the (N,N(s)) plane is displayed and analyzed in the case of homogeneous external magnetic fields B(r). The (negative of the) left-/right-side derivatives of the energy with respect to N, N(?), and N(?) give the fixed-N(s), spin-up, and spin-down ionization potentials/electron affinities, respectively, while the derivative of E[N,N(s),v,B] with respect to N(s) gives the (signed) half excitation energy to the lowest-lying state with N(s) increased (or decreased) by 2. The highest occupied and lowest unoccupied Kohn-Sham spin-orbital energies are identified as the corresponding spin-up and spin-down ionization potentials and electron affinities. The excitation energies to the lowest-lying states with N(s)±2 can be obtained as the differences between the lowest unoccupied and the opposite-spin highest occupied spin-orbital energies, if the (N,N(s)) representation of the Kohn-Sham spin-potentials is used. The cases where the convexity condition on the energy does not hold are also discussed. Finally, the discontinuities of the energy derivatives and the Kohn-Sham potential are analyzed and related. PMID:20949985

Gál, T; Geerlings, P

2010-10-14

436

Effect of combined local variations in elastic and inelastic energy losses on the morphology of tracks in ion-irradiated materials  

SciTech Connect

A judicious choice of irradiation parameters and experimental methodology allowed the visualization of the tracks created by swift heavy ions in pyrochlores over the entire ion trajectories. Several peculiarities were observed: a layered structure of tracks composed of an amorphous core surrounded by a strained crystalline envelope, a change of the track diameter as a function of the ion slowing down, a loss of parallelism of tracks, a transformation from continuous to discontinuous regime, and an increasing contribution of elastic collisions at large depths. These observations are compared to the respective amount of electronic and nuclear energy losses.

Jozwik Biala, Iwona; Jagielski, Jacek K.; Arey, Bruce W.; Kovarik, Libor; Sattonay, G.; Debelle, A.; Mylonas, S.; Monnet, I.; Thome, Lionel

2013-07-13

437

Investigation of nuclear matter distribution of the neutron-rich He isotopes by proton elastic scattering at intermediate energies  

NASA Astrophysics Data System (ADS)

Absolute differential cross-sections for elastic p6He and p8He scattering were measured in inverse kinematics with secondary beams. In order to supplement data taken for small-angle scattering, differential cross-sections for higher momentum transfer were measured using liquid hydrogen target. Both data sets were analyzed together. They have permitted to deduce the radial shape of the nuclear matter distributions and the root-mean-square radii with the help of Glauber theory. In addition to a phenomenological analysis, used already in the previous work, a model-independent analysis with a help of a Sum-Of-Gaussians (SOG) method has been performed. The experimental p6,8He elastic scattering cross-sections have also been compared with the predictions from various theoretical nuclear models.

Kiselev, O. A.; Aksouh, F.; Bleile, A.; Bochkarev, O. V.; Chulkov, L. V.; Cortina-Gil, D.; Dobrovolsky, A. V.; Egelhof, P.; Geissel, H.; Hellström, M.; Isaev, N. B.; Komkov, B. G.; Mátos, M.; Moroz, F. V.; Münzenberg, G.; Mutterer, M.; Mylnikov, V. A.; Neumaier, S. R.; Pribora, V. N.; Seliverstov, D. M.; Sergueev, L. O.; Shrivastava, A.; Sümmerer, K.; Weick, H.; Winkler, M.; Yatsoura, V. I.

2005-09-01

438

Gravitational potential energy of the earth - A spherical harmonic approach  

NASA Technical Reports Server (NTRS)

A spherical harmonic equation for the gravitational potential energy of the earth is derived for an arbitrary density distribution by conceptually bringing in mass-elements from infinity and building up the earth shell upon spherical shell. The zeroth degree term in the spherical harmonic expansion agrees with the usual expression for the energy of a radial density distribution. The second degree terms give a maximum nonhydrostatic energy in the crust and mantle of -2.77 x 10 to the 29th ergs, an order of magnitude below McKenzie's (1966) estimate. McKenzie's result stems from mathematical error. Our figure is almost identical with Kaula's (1963) estimate of the minimum shear strain energy in the mantle, a not unexpected result on the basis of the virial theorem. If the earth is assumed to be a homogeneous viscous oblate spheroid relaxing to an equilibrium shape, then a lower limit to the mantle viscosity of 1.3 x 10 to the 20th P is found by assuming that the total geothermal flux is due to viscous dissipation of energy. This number is almost six orders of magnitude below MacDonald's (1966) estimate of the viscosity and removes his objection to convection. If the nonequilibrium figure is dynamically maintained by the earth acting as a heat engine at 1% efficiency, then the viscosity is 10 to the 22nd P, a number preferred by Cathles (1975) and Peltier and Andrew (1976) as the viscosity of the mantle.

Rubincam, D. P.

1979-01-01

439

Potential impacts of nanotechnology on energy transmission applications and needs.  

SciTech Connect

The application of nanotechnologies to energy transmission has the potential to significantly impact both the deployed transmission technologies and the need for additional development. This could be a factor in assessing environmental impacts of right-of-way (ROW) development and use. For example, some nanotechnology applications may produce materials (e.g., cables) that are much stronger per unit volume than existing materials, enabling reduced footprints for construction and maintenance of electricity transmission lines. Other applications, such as more efficient lighting, lighter-weight materials for vehicle construction, and smaller batteries having greater storage capacities may reduce the need for long-distance transport of energy, and possibly reduce the need for extensive future ROW development and many attendant environmental impacts. This report introduces the field of nanotechnology, describes some of the ways in which processes and products developed with or incorporating nanomaterials differ from traditional processes and products, and identifies some examples of how nanotechnology may be used to reduce potential ROW impacts. Potential environmental, safety, and health impacts are also discussed.

Elcock, D.; Environmental Science Division

2007-11-30

440

Design of potential energy surfaces for chemical reactions  

SciTech Connect

The design of potential energy surfaces for two systems is considered. The first study presented is for the abstraction reaction F + H/sub 2/ ..-->.. HF + H and the exchange reaction H' + FH ..-->.. FH' + H and their related isotopic analogs. Several surfaces are proposed which incorporate both experimental and ab initio information. The new surfaces are of the form of the extended London-Eyring-Polanyi method but with angle-and distance-dependent Sato parameters and an added three-center term. The first new surface is fit using empirical data in the entrance channel but only ab initio data in the exit channel. Preliminary studies on the role of dynamical bottlenecks in the exit-channel are used to locate the crucial regions of the surface where accurate calculations are needed. A second surface is a slightly modified version of the first in which experimental information is used to recalibrate the abstraction exit channel. Two additional surfaces presented here are designed to test the effect of a higher entrance-channel saddle point on the dynamics. A study of potential energy surfaces for the reaction CH/sub 3/ + H/sub 2/ ..-->.. CH/sub 4/ + H is also presented. This includes a thorough analysis of existing surfaces and dynamics calculations using slightly modified forms of these surfaces. Two new surfaces are calibrated using both ab initio and experimental data. Rate constants, activation energies, and kinetic isotope effects calculated using the new surfaces are compared to experiment.

Steckler, R.

1986-01-01

441

Very High Energy Blazars and the Potential for Cosmological Insight  

NASA Astrophysics Data System (ADS)

Gamma-ray blazars are among the most extreme astrophysical sources, harboring phenomena far more energetic than those attainable by terrestrial accelerators. These galaxies are understood to be active galactic nuclei that are powered by accretion onto supermassive black holes and have relativistic jets pointed along the Earth line of sight. The emission displayed is variable at all wavelengths and timescales probed thus far, necessitating contemporaneous broadband observations to disentangle the details of the emission processes within the relativistic jets. The very high energy (VHE; E> 100 GeV) photons emitted by these sources are detectable with ground based imaging atmospheric Cherenkov telescopes such as VERITAS. As these photons propagate extragalactic distances, the interaction with the diffuse starlight that pervades the entire Universe results in a distance and energy dependent gamma-ray opacity, offering a unique method for probing photon densities on cosmological scales. These galaxies have also been postulated to be potential sources of ultra-high-energy cosmic rays, a theory which can be examined through the deep gamma-ray observations of sources which probe moderate gamma-ray opacities. Within this talk, I will highlight ongoing research regarding the broadband emission from VERITAS-observed VHE blazars, as well as the potential to use them for cosmological insight.

Furniss, Amy

2014-08-01

442

Elasticity and Geomechanics  

Microsoft Academic Search

This book concisely examines the use of elasticit