These are representative sample records from Science.gov related to your search topic.
For comprehensive and current results, perform a real-time search at Science.gov.
1

Polarization potential for elastic scattering of {sup 6,7}Li + {sup 28}Si at near-barrier energies  

SciTech Connect

The polarization potential for the elastic scattering of {sup 6,7}Li + {sup 28}Si at near barrier energies has been investigated in the context of an optical model framework. The effect on the elastic scattering was found to be strong, energy dependent, and compatible with the transfer channel.

Pakou, Athena [Department of Physics, The University of Ioannina, GR-45110 Ioannina (Greece)

2008-12-15

2

Probing the 17F+p potential by elastic scattering at near-barrier energies  

NASA Astrophysics Data System (ADS)

Proton elastic scattering angular distributions for the reaction 17F+p, were measured in inverse kinematics over a wide angular range (?c.m.=50?-160?) at two near-barrier energies of 3.5 and 4.3 MeV/u. The optical potential was probed in a phenomenological and microscopic approach. Moreover, total reaction cross-sections were also determined via optical potential analysis and were used as a signature for probing a possible halo structure of this proton-rich nucleus.

Patronis, N.; Pakou, A.; Pierroutsakou, D.; Sánchez-Benítez, A. M.; Acosta, L.; Alamanos, N.; Boiano, A.; Inglima, G.; Filipescu, D.; Glodariu, T.; Guglielmetti, A.; La Commara, M.; Lalazissis, G.; Martel, I.; Mazzocchi, C.; Mazzocco, M.; Molini, P.; Parascandolo, C.; Sandoli, M.; Signorini, C.; Silvestri, R.; Soramel, F.; Stiliaris, E.; Romoli, M.; Trzcinska, A.; Zerva, K.; Vardaci, E.; Vitturi, A.

2012-02-01

3

Elastic alpha scattering experiments and the alpha-nucleus optical potential at low energies  

SciTech Connect

High precision angular distribution data of (?,?) elastic scattering are presented for the nuclei {sup 89}Y, {sup 92}Mo, {sup 106,110,116}Cd, {sup 112,124}Sn, and {sup 144}Sm at energies around the Coulomb barrier. Such data with small experimental uncertainties over the full angular range (20–170°) are the indispensable prerequisite for the extraction of local optical potentials and for the determination of the total reaction cross section ?{sub reac}. A systematic fitting procedure was applied to the experimental scattering data presented to obtain comprehensive local potential parameter sets that are composed of a real folding potential and an imaginary potential of Woods–Saxon surface type. The potential parameters obtained were used in turn to construct a new systematic ?-nucleus potential with very few parameters. Although this new potential cannot reproduce the angular distributions with the same small deviations as the local potential, the new potential is able to predict the total reaction cross sections for all cases under study.

Mohr, P., E-mail: mohr@atomki.mta.hu [Institute of Nuclear Research (ATOMKI), H-4001 Debrecen (Hungary); Diakonie-Klinikum, D-74523 Schwäbisch Hall (Germany)] [Germany; Kiss, G.G.; Fülöp, Zs. [Institute of Nuclear Research (ATOMKI), H-4001 Debrecen (Hungary)] [Institute of Nuclear Research (ATOMKI), H-4001 Debrecen (Hungary); Galaviz, D. [Centro de Física Nuclear, University of Lisbon, P-1649-003 Lisbon (Portugal)] [Centro de Física Nuclear, University of Lisbon, P-1649-003 Lisbon (Portugal); Gyürky, Gy.; Somorjai, E. [Institute of Nuclear Research (ATOMKI), H-4001 Debrecen (Hungary)] [Institute of Nuclear Research (ATOMKI), H-4001 Debrecen (Hungary)

2013-11-15

4

Complementary optical-potential analysis of {alpha}-particle elastic scattering and induced reactions at low energies  

SciTech Connect

A previously derived semi-microscopic analysis based on the Double Folding Model, for {alpha}-particle elastic scattering on A{approx}100 nuclei at energies below 32 MeV, is extended to medium mass A{approx}50-120 nuclei and energies from {approx}13 to 50 MeV. The energy-dependent phenomenological imaginary part for this semi-microscopic optical model potential was obtained including the dispersive correction to the microscopic real potential, and used within a concurrent phenomenological analysis of the same data basis. A regional parameter set for low-energy {alpha}-particles entirely based on elastic scattering data analysis was also obtained for nuclei within the above mentioned mass and energy ranges. Then, an ultimate assessment of ({alpha},{gamma}), ({alpha},n), and ({alpha},p) reaction cross sections considered target nuclei from {sup 45}Sc to {sup 118}Sn and incident energies below {approx}12 MeV. The former diffuseness of the real part of optical potential as well as the surface imaginary potential depth have been found to be responsible for the actual difficulties in the description of these data, and modified in order to obtain an optical potential which describes equally well both the low-energy elastic scattering and induced reaction data for {alpha}-particles.

Avrigeanu, M. ['Horia Hulubei' National Institute for Physics and Nuclear Engineering, P.O. Box MG-6, 76900 Bucharest (Romania)], E-mail: mavrig@ifin.nipne.ro; Obreja, A.C.; Roman, F.L.; Avrigeanu, V. ['Horia Hulubei' National Institute for Physics and Nuclear Engineering, P.O. Box MG-6, 76900 Bucharest (Romania); Oertzen, W. von [Freie Universitaet Berlin, Fachbereich Physik, Arnimallee 14, 14195 Berlin (Germany); Hahn-Meitner-Institut, Glienicker Strasse 100, 14109 Berlin (Germany)

2009-07-15

5

Empirical interatomic potential for silicon with improved elastic properties  

Microsoft Academic Search

An alternative parametrization is given for a previous empirical interatomic potential for silicon. The new potential is designed to more accurately reproduce the elastic properties of silicon, which were poorly described in the earlier potential. The properties of liquid Si are also improved, but energies of surfaces are less accurate. Detailed tests of the new potential are described.

J. Tersoff

1988-01-01

6

Elasticity cells. An investigation of the relation between the energy liberated by a strained metal going into solution and the potential difference resulting.  

E-print Network

ELASTICITY CELLS. AN INVESTIGATION OF THE RELATION BETWEEN THE ENERGY LIBERATED BY A STRAINED METAL GOING INTO SOLUTION, AND THE POTENTIAL DIFFERENCE RESULTING. A thesis submitted to the Department of Physios of the University of Kansas... the relation between the energy liberated by a metal going Into solution, and the poten- tial difference resulting* From theoretical considerations Thoraeon deduced the following equation for the electro-motive force of a cell. E- Z. H. J. where Z...

Power, Archie Dayton

1912-06-01

7

Potentials for the ?– 40,44,48Ca elastic scattering  

Microsoft Academic Search

The differential cross sections for the elastic scattering of ? particles by 40,44,48Ca, over a wide range of incident energies, have been analyzed using a deep as well as shallow non-monotonic optical potential and compared with those using a squared Woods–Saxon (SWS) potential. The shallow non-monotonic potential exhibits a volume integral for the real part, characteristic of a molecular potential.

M. N. A. Abdullah; A. B. Idris; A. S. B. Tariq; M. S. Islam; S. K. Das; M. A. Uddin; A. S. Mondal; A. K. Basak; I. Reichstein; H. M. Sen Gupta; F. B. Malik

2005-01-01

8

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

9

Elastic lattice in a random potential  

SciTech Connect

Using Monte Carlo simulations, we study the properties of an elastic triangular lattice subject to a random background potential. As the cooling rate is reduced, we observe a rather sudden crossover between two different glass phases, with exponential decay of translational correlations, the other with power-law decay. Contrary to predictions derived for continuum models, no evidence of a crossover in the mean-square displacement B(r) from the quadratic growth at small r to the logarithmic growth at large r is found. {copyright} {ital 1998} {ital The American Physical Society}

Chudnovsky, E.M.; Dickman, R. [Department of Physics and Astronomy, Lehman College, CUNY, Bedford Park Boulevard West, Bronx, New York 10468-1589 (United States)] [Department of Physics and Astronomy, Lehman College, CUNY, Bedford Park Boulevard West, Bronx, New York 10468-1589 (United States)

1998-02-01

10

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

11

High energy elastic and diffractive scattering  

SciTech Connect

The developments in high energy pp and p{bar p} elastic scattering in the last 30 years are summarized. The Regge pole model and the geometrical models are reviewed and their agreement with experimental data discussed. The experimental method for measuring the total cross section and the ratio of the real to the imaginary part of the forward elastic scattering amplitude, p, is described. The asymptotic behavior of the total cross section at high energy is discussed in the light of the new results on p{bar p} elastic scattering at {radical}s=1.8 TeV. Predictions from geometrical models and Regge phenomenology are compared with experimental data. The 2-gluon model of the Pomeron by Low and Nussinov is discussed. Future measurements on elastic pp and p{bar p} elastic scattering are discussed.

Shukla, S.

1992-08-01

12

Information on Short-Range Nucleon-Nucleon Correlations and Woods-Saxon Nuclear Potential from High-Energy Elastic Electron Scattering  

Microsoft Academic Search

A method has been developed which allows the effect of the short-range dynamical correlations on the nuclear-charge form factors generated in arbitrary potential wells to be taken into account. Recent highenergy experimental data on elastic electron scattering by 6Li, 12C, and 16O have been analyzed with this method. The single-particle radial wave functions have been generated in a state-dependent Woods-Saxon

C. Ciofi Atti; N. M. Kabachnik

1970-01-01

13

Close-coupling calculations of low-energy inelastic and elastic processes in $^4$He collisions with H$_2$: A comparative study of two potential energy surfaces  

E-print Network

The two most recently published potential energy surfaces (PESs) for the HeH$_2$ 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 H$_2$($\

T. G. Lee; C. Rochow; R. Martin; T. K. Clark; R. C. Forrey; N. Balakrishnan; P. C. Stancil; D. R. Schultz; A. Dalgarno; G. J. Ferland

2004-12-09

14

Elasticity of a system with non-central potentials  

E-print Network

We derive expressions for determination of the stress and the elastic constants in systems composed of particles interacting via non-central two-body potentials as thermal averages of products of first and second partial derivatives of the interparticle potentials and components of the interparticle separation vectors. These results are adapted to hard potentials, when the stress and the elastic constants are expressed as thermal averages of the components of normals to contact surfaces between the particles and components of vectors separating the centers of the particles. The averages require the knowledge of simultaneous contact probabilities of two pairs of particles. We apply the expressions to particles for which a contact function can be defined, and demonstrate the feasibility of the method by computing the stress and the elastic constants of a two-dimensional system of hard ellipses using Monte Carlo simulations.

Michael Murat; Yacov Kantor

2006-06-01

15

Calculations of $^{6}$He+p elastic scattering cross sections using folding approach and high-energy approximation for the optical potential  

E-print Network

Calculations of microscopic optical potentials (OP's) (their real and imaginary parts) are performed to analyze the $^6$He+p elastic scattering data at a few tens of MeV/nucleon (MeV/N). The OP's and the cross sections are calculated using three model densities of $^6$He. Effects of the regularization of the NN forces and their dependence on nuclear density are investigated. Also, the role of the spin-orbit terms and of the non-linearity in the calculations of the OP's, as well as effects of their renormalization are studied. The sensitivity of the cross sections to the nuclear densities was tested and one of them that gives a better agreement with the data was chosen.

K. V. Lukyanov; V. K. Lukyanov; E. V. Zemlyanaya; A. N. Antonov; M. K. Gaidarov

2007-08-27

16

Elastic epsilon/sup + -/-He scattering with the use of the model-potential method  

SciTech Connect

A model-potential method has been used to evaluate the elastic e/sup + -/-He scattering at the low-incident energies. The potential contains one parameter to include the effect of short-range correlation. The results for the elastic e/sup + -/-He scattering have been obtained using the same parameter. Two model exchange potentials, one for s wave and the other for higher partial waves, have been employed. The present results are in good agreement with the measured values and refined theoretical predictions.

Khan, P.; Datta, S.K.; Bhattacharyya, D.; Ghosh, A.S.

1984-06-01

17

Folding model study of the elastic $?+ ?$ scattering at low energies  

E-print Network

The folding model analysis of the elastic $\\alpha + \\alpha$ scattering at the incident energies below the reaction threshold of 34.7 MeV (in the lab system) has been done using the well-tested density dependent versions of the M3Y interaction and realistic choices for the $^4$He density. Because the absorption is negligible at the energies below the reaction threshold, we were able to probe the $\\alpha + \\alpha$ optical potential at low energies quite unambiguously and found that the $\\alpha + \\alpha$ overlap density used to construct the density dependence of the M3Y interaction is strongly distorted by the Pauli blocking. This result gives possible explanation of a long-standing inconsistency of the double-folding model in its study of the elastic $\\alpha + \\alpha$ and $\\alpha$-nucleus scattering at low energies using the same realistic density dependent M3Y interaction.

Ngo Hai Tan; Nguyen Hoang Phuc; Dao T. Khoa

2014-03-13

18

pp Elastic Scattering at LHC Energies  

E-print Network

Using a unified analytic representation for the elastic scattering amplitudes of pp scattering valid for all energy region, the behavior of observables in the LHC collisions in the range $\\sqrt{s}$= 2.76 - 14 TeV is discussed. Similarly to the case of 7 TeV data, the proposed amplitudes give excellent description of the preliminary 8 TeV data. We discuss the expected energy dependence of the observable quantities, and present predictions for the experiments at 2.76, 13 and 14 TeV.

Anderson Kendi Kohara; Erasmo Ferreira; Takeshi Kodama

2014-08-07

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

An Expression for the Granular Elastic Energy  

E-print Network

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 draw-backs. 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 $26^\\circ$ to the more realistic value of $30^\\circ$. (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.

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

2012-06-13

21

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

22

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

23

Elastic constants of defected and amorphous silicon with the environment-dependent interatomic potential  

SciTech Connect

The elastic constants of a wide range of models of defected crystalline and amorphous silicon are calculated, using the environment-dependent interatomic potential (EDIP). The defected crystalline simulation cells contain randomly generated defect distributions. An extensive characterization of point defects is performed, including structure, energy and influence on elastic constants. Three important conclusions are drawn. (1) Defects have independent effects on the elastic constants of silicon up to (at least) a defect concentration of 0.3%. (2) The linear effect of Frenkel pairs on the <110> Young's modulus of silicon is -1653 GPa per defect fraction. (3) 17 different point defect types cause a very similar decrease in the <110> Young's modulus: -(0.28{+-}0.05)% when calculated in isolation using a 1728-atom cell. These principles will be very useful for predicting the effect of radiation damage on the elastic modulus of silicon in the typical case in which point-defect concentrations can be estimated, but the exact distribution and species of defects is unknown. We also study amorphous samples generated in quenching the liquid with EDIP, including an ideal structure of perfect fourfold coordination, samples with threefold and fivefold coordinated defects, one with a nanovoid, and one with an amorphous inclusion in a crystalline matrix. In the last case, a useful finding is that the change in the Young's modulus is simply related to the volume fraction of amorphous material, as has also been observed by experiment.

Allred, Clark L. [Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Charles Stark Draper Laboratory, Inc., 555 Technology Square, Cambridge, Massachusetts 02139 (United States); Air Force Institute of Technology, Wright-Patterson AFB, Ohio 45433 (United States); Yuan Xianglong; Hobbs, Linn W. [Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Bazant, Martin Z. [Department of Mathematics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

2004-10-01

24

Elastic constants of defected and amorphous silicon with the environment-dependent interatomic potential  

NASA Astrophysics Data System (ADS)

The elastic constants of a wide range of models of defected crystalline and amorphous silicon are calculated, using the environment-dependent interatomic potential (EDIP). The defected crystalline simulation cells contain randomly generated defect distributions. An extensive characterization of point defects is performed, including structure, energy and influence on elastic constants. Three important conclusions are drawn. (1) Defects have independent effects on the elastic constants of silicon up to (at least) a defect concentration of 0.3%. (2) The linear effect of Frenkel pairs on the ?110? Young’s modulus of silicon is -1653GPa per defect fraction. (3) 17 different point defect types cause a very similar decrease in the ?110? Young’s modulus: -(0.28±0.05)% when calculated in isolation using a 1728-atom cell. These principles will be very useful for predicting the effect of radiation damage on the elastic modulus of silicon in the typical case in which point-defect concentrations can be estimated, but the exact distribution and species of defects is unknown. We also study amorphous samples generated in quenching the liquid with EDIP, including an ideal structure of perfect fourfold coordination, samples with threefold and fivefold coordinated defects, one with a nanovoid, and one with an amorphous inclusion in a crystalline matrix. In the last case, a useful finding is that the change in the Young’s modulus is simply related to the volume fraction of amorphous material, as has also been observed by experiment.

Allred, Clark L.; Yuan, Xianglong; Bazant, Martin Z.; Hobbs, Linn W.

2004-10-01

25

High Energy Elastic pp Scattering in Additive Quark Model  

E-print Network

High energy $pp$ elastic scattering is treated in the framework of Additive Quark Model. The reasonable agreement with experimental data is achieved with natural parameters for the strong matter distribution inside proton.

Yu. M. Shabelski; A. G. Shuvaev

2014-06-05

26

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

27

Teaching about Energy: Dependence of Elastic Energy on Position  

NSDL National Science Digital Library

This student activity is designed to explore the potential energy of springs. By hanging different masses on a spring, students are lead to determine the potential energy in a stretched spring. Included are notes for instructors wishing to use this material. This activity is part of a PTRA manual on Energy.

Roeder, John

2006-06-14

28

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

PubMed

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 of representative arachnids. Extension torques of isolated joints with and without transarticular sclerites were measured as the joint was rotated through angles and at angular velocities comparable with those used by walking animals. The procedure was repeated with the joint subjected to different internal fluid pressures in order to assess the potential role of hydraulically induced extension. The efficiency of elastic energy storage (resilience) in the absence of internal fluid pressure was 70-90% for joints with well-developed transarticular sclerites, and the magnitude of torque was similar to those produced by different joint extension mechanisms in other arthropods. Increased internal fluid pressure acted synergistically with transarticular sclerites in some joints but had little or no effect in others. Joints that lacked both extensor muscles and transarticular sclerites appeared to be specialized for hydraulic extension, and joints operated by antagonistic muscles lacked apparent specializations for either elastic or hydraulic extension. It is well known that elastic energy storage is a significant contributor to propulsion in running vertebrates and certain arthropods, where elastic elements are loaded as the center of mass falls during one phase of the locomotor cycle. However, transarticular sclerites are apparently loaded by contraction of flexor muscles when the leg is not in contact with the substratum. Hence the mechanism of a transarticular sclerite is more similar to the flight and jumping mechanisms of other arthropods than to running vertebrates. The evolutionary significance and potential mechanical advantages of the transarticular elastic mechanism are discussed. PMID:12517993

Sensenig, Andrew T; Shultz, Jeffrey W

2003-02-01

29

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

30

LETTER TO THE EDITOR: Positronium-hydrogen atom elastic scattering at medium energies  

NASA Astrophysics Data System (ADS)

We study the elastic scattering of positronium atoms by hydrogen atoms at medium energies using partial-wave Born-Oppenheimer (BO) exchange amplitudes and report accurate BO cross sections in the energy range 0 to 60 eV. The present BO results agree with a 22-state R-matrix and a five-state coupled-channel model potential calculation, but disagree strongly with a conventional close-coupling calculation as well as its input BO amplitudes at medium energies.

Adhikari, Sadhan K.; Mandal, Puspajit

2000-10-01

31

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

32

Calculation of the Temperature Dependence of the Second-Order Elastic Constants of fcc Ar, Kr, and Xe Using a Two-Body Short-Range Interatomic Potential  

Microsoft Academic Search

The temperature dependence of the second-order elastic constants of fcc Ar, Kr, and Xe have been studied using phenomenological (m-6) Lennard-Jones potentials acting between nearest neighbors and fitted to the zero-temperature zero-pressure lattice constant and the sublimation energy. The theory of the second-order elastic constants is briefly reviewed, and the second-order strain dependence of the quasiharmonic free-energy density is derived

C. Feldman; M. L. Klein; G. K. Horton

1969-01-01

33

Elastic cross sections for high energy hadron-hadron scattering  

E-print Network

This report discusses some results on differential cross sections for high energy and small momentum transfer elastic hadron-hadron scattering in QCD, using a functional integral approach. In particulary a matrix cumulant expansion for the vacuum expectation values of lightlike Wegner-Wilson loops, which governs the hadronic amplitudes, is presented. The cumulants are evaluated using the model of the stochastic vacuum.

E. R. Berger

1998-11-11

34

Ubiquitous Low Energy Structures in Differential Elastic Electron Molecule Scattering  

Microsoft Academic Search

In recent years detailed, low energy, elastic electron-molecule scattering experiments in our laboratory and others, have revealed alluring structures in angular differential cross sections which occur at scattering angles around 20-50^o. They take the form of a shallow minimum\\/maximum which develops, and then disappears, over a very small impact energy range, typically between 3-7 eV. They have been observed in

Stephen J. Buckman; Lewis T. Chadderton

1999-01-01

35

Electromagnetic Coulomb gas with vector charges and “elastic” potentials: Renormalization group equations  

NASA Astrophysics Data System (ADS)

We present a detailed derivation of the renormalization group equations for two-dimensional electromagnetic Coulomb gases whose charges lie on a triangular lattice (magnetic charges) and its dual (electric charges). The interactions between the charges involve both angular couplings and a new electromagnetic potential. This motivates the denomination of "elastic" Coulomb gas. Such elastic Coulomb gases arise naturally in the study of the continuous melting transition of two-dimensional solids coupled to a substrate, either commensurate or with quenched disorder.

Carpentier, David; Le Doussal, Pierre

2008-06-01

36

An energy formulation of continuum magneto-electro-elasticity with applications  

NASA Astrophysics Data System (ADS)

We present an energy formulation of continuum electro-elasticity and magneto-electro-elasticity. Based on the principle of minimum free energy, we propose a form of total free energy of the system in three dimensions, and then systematically derive the theories for a hierarchy of materials including dielectric elastomers, piezoelectric ceramics, ferroelectrics, flexoelectric materials, magnetic elastomers, magnetoelectric materials, piezo-electric-magnetic materials among others. The effects of mechanical, electrical and magnetic boundary devices, external charges, polarizations and magnetization are taken into account in formulating the free energy. The linear and nonlinear boundary value problems governing these materials are explicitly derived as the Euler-Lagrange equations of the principle of minimum free energy. Finally, we illustrate the applications of the formulations by presenting solutions to a few simple problems and give an outlook of potential applications.

Liu, Liping

2014-02-01

37

Surface energy, elasticity and the homogenization of rough surfaces  

NASA Astrophysics Data System (ADS)

The concept of surface energy is widely used to understand numerous aspects of material behavior: fracture, self-assembly, catalysis, void formation, microstructure evolution, and size-effect exhibited by nanostructures. Extensive work exists on deriving homogenized constitutive responses for macroscopic composites—relating effective properties to various microstructural details. In the present work, we focus on homogenization of surfaces. Indeed, elucidation of the effect of surface roughness on the surface energy, stress, and elastic behavior is relatively under-studied and quite relevant to the behavior of both nanostructures and bulk material where surfaces are involved in some form or fashion. We present derivations that relate both periodic and random roughness to the effective surface elastic behavior. We find that the residual surface stress is hardly affected by roughness while the superficial elastic properties are dramatically altered and, importantly, they may also change sign—this has significant ramifications in the interpretation of sensing based on frequency measurement changes. Interestingly, even if the bare surface has a zero surface elasticity modulus, roughness is seen to endow it with one. Using atomistic calculations, we verify the qualitative validity of the obtained theoretical insights. We show, through an illustrative example, that the square of resonance frequency of a cantilever beam with rough surface can decrease almost by a factor of two compared to a flat surface.

Mohammadi, P.; Liu, L. P.; Sharma, P.; Kukta, R. V.

2013-02-01

38

Low-Energy Elastic Electron Scattering by Atomic Oxygen  

NASA Technical Reports Server (NTRS)

The B-spline R-matrix method is employed to investigate the low-energy elastic electron scattering by atomic oxygen. Flexible non-orthogonal sets of radial functions are used to construct the target description and to represent the scattering functions. A detailed investigation regarding the dependence of the predicted partial and total cross sections on the scattering model and the accuracy of the target description is presented. The predicted angle-integrated elastic cross sections are in good agreement with experiment, whereas significant discrepancies are found in the angle-differential elastic cross sections near the forward direction. .The near-threshold results are found to strongly depend on the treatment of inner-core short-range correlation effects in the target description, as well as on a proper account of the target polarizability. A sharp increase in the elastic cross sections below 1 eV found in some earlier calculations is judged to be an artifact of an unbalanced description of correlation in the N-electron target structure and the (N+l)-electron-collision problems.

Zatsarinny O.; Bartschat, K.; Tayal, S. S.

2006-01-01

39

Topics on High-Energy Elastic Hadron Scattering  

E-print Network

We review the main results we have obtained in the area of high-energy elastic hadron scattering and presented in this series of Workshops on Hadronic Interactions. After an introduction to some basic experimental and theoretical concepts, we survey the results reached by means of four approaches: analytic models, model-independent analyses, eikonal models and nonperturbative QCD. Some of the ongoing researches and future perspectives are also outlined.

M. J. Menon

2004-11-30

40

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

41

Semiphenomenological method of analysis for intermediate-energy alpha-nucleus elastic scattering data  

SciTech Connect

We propose a semiphenomenological method of analysis for intermediate energy ..cap alpha..-nucleus elastic scattering experiments and demonstrate its usefulness by analyzing available elastic ..cap alpha..-nucleus scattering data at 1.37 GeV.

Ahmad, I.; Alvi, M.A.

1983-12-01

42

Elastic Free Energy Drives the Shape of Prevascular Solid Tumors  

PubMed Central

It is well established that the mechanical environment influences cell functions in health and disease. Here, we address how the mechanical environment influences tumor growth, in particular, the shape of solid tumors. In an in vitro tumor model, which isolates mechanical interactions between cancer tumor cells and a hydrogel, we find that tumors grow as ellipsoids, resembling the same, oft-reported observation of in vivo tumors. Specifically, an oblate ellipsoidal tumor shape robustly occurs when the tumors grow in hydrogels that are stiffer than the tumors, but when they grow in more compliant hydrogels they remain closer to spherical in shape. Using large scale, nonlinear elasticity computations we show that the oblate ellipsoidal shape minimizes the elastic free energy of the tumor-hydrogel system. Having eliminated a number of other candidate explanations, we hypothesize that minimization of the elastic free energy is the reason for predominance of the experimentally observed ellipsoidal shape. This result may hold significance for explaining the shape progression of early solid tumors in vivo and is an important step in understanding the processes underlying solid tumor growth. PMID:25072702

Mills, K. L.; Kemkemer, Ralf; Rudraraju, Shiva; Garikipati, Krishna

2014-01-01

43

Elastic free energy drives the shape of prevascular solid tumors.  

PubMed

It is well established that the mechanical environment influences cell functions in health and disease. Here, we address how the mechanical environment influences tumor growth, in particular, the shape of solid tumors. In an in vitro tumor model, which isolates mechanical interactions between cancer tumor cells and a hydrogel, we find that tumors grow as ellipsoids, resembling the same, oft-reported observation of in vivo tumors. Specifically, an oblate ellipsoidal tumor shape robustly occurs when the tumors grow in hydrogels that are stiffer than the tumors, but when they grow in more compliant hydrogels they remain closer to spherical in shape. Using large scale, nonlinear elasticity computations we show that the oblate ellipsoidal shape minimizes the elastic free energy of the tumor-hydrogel system. Having eliminated a number of other candidate explanations, we hypothesize that minimization of the elastic free energy is the reason for predominance of the experimentally observed ellipsoidal shape. This result may hold significance for explaining the shape progression of early solid tumors in vivo and is an important step in understanding the processes underlying solid tumor growth. PMID:25072702

Mills, K L; Kemkemer, Ralf; Rudraraju, Shiva; Garikipati, Krishna

2014-01-01

44

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

45

12C+12C elastic scattering analysis above E/A=6 MeV using deep real potentials  

NASA Astrophysics Data System (ADS)

We present phenomenological and folding optical-model descriptions of 12C+12C elastic scattering between 6 and 120 MeV/nucleon. The potentials have a deep real part, a weakly absorbing imaginary part, and are energy dependent. The folding-model real potential is calculated from the energy- and density-dependent effective interaction DDM3Y. It requires renormalizations of about 1.1 below 10 MeV/nucleon, and close to unity above. The phenomenological real potential is about 300 MeV at the center for the lower energies, slowly reducing to 120 MeV for the highest energies. The discrete ambiguities for the real part found in the analysis at energies below 10 MeV/nucleon are resolved by demanding consistency with the higher energy results. The volume integrals for the folding-model and phenomenological potentials agree and display a smooth and slow energy dependence that is consistent with simple dispersion-relation predictions. The values for the total reaction cross sections show the transparency effect expected from microscopic calculations. A possible extension of this description towards lower energies is discussed.

Brandan, M. E.; Rodrguez-Villafuerte, M.; Ayala, A.

1990-04-01

46

sup 12 C+ sup 12 C elastic scattering analysis above E / A =6 MeV using deep real potentials  

SciTech Connect

We present phenomenological and folding optical-model descriptions of {sup 12}C+{sup 12}C elastic scattering between 6 and 120 MeV/nucleon. The potentials have a deep real part, a weakly absorbing imaginary part, and are energy dependent. The folding-model real potential is calculated from the energy- and density-dependent effective interaction DDM3Y. It requires renormalizations of about 1.1 below 10 MeV/nucleon, and close to unity above. The phenomenological real potential is about 300 MeV at the center for the lower energies, slowly reducing to 120 MeV for the highest energies. The discrete ambiguities for the real part found in the analysis at energies below 10 MeV/nucleon are resolved by demanding consistency with the higher energy results. The volume integrals for the folding-model and phenomenological potentials agree and display a smooth and slow energy dependence that is consistent with simple dispersion-relation predictions. The values for the total reaction cross sections show the transparency effect expected from microscopic calculations. A possible extension of this description towards lower energies is discussed.

Brandan, M.E.; Rodriguez-Villafuerte, M.; Ayala, A. (Universidad Nacional Autonoma de Mexico, Apartado Postal 20-364, Mexico 01000 Distrito Federal, Mexico (MX))

1990-04-01

47

The general properties of the equations of the non-linear theory of elasticity for piecewise-linear potentials  

Microsoft Academic Search

A theory of elasticity for piecewise-linear potentials is constructed assuming that the elastic potential consists of two terms, one of which depends on the hydrostatic pressure and other on the equivalent stress, which is a homogeneous function of the first power of the stress deviator. These assumptions limit the class of possible models compared with the previous assumptions [1], but

G. I. Bykovtsev

1996-01-01

48

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

NASA Astrophysics Data System (ADS)

We have studied the dynamical effects of the halo structure of 11Li 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 11Li beam. As part of this study we report here on the first measurement of the elastic cross section of the core nucleus, i.e. 9Li on 208Pb, 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.; Fernández-García, J. P.; Lay, J. A.; Acosta, L.; Alcorta, M.; Alvarez, M. A. G.; Borge, M. J. G.; Buchmann, L.; Diget, D. G.; Fulton, B.; Fynbo, H. O. U.; Galaviz, D.; Gómez-Camacho, J.; Martel, I.; Moro, A. M.; Mukha, I.; Nilsson, T.; Sánchez-Benítez, A. M.; Shotter, A.; Tengblad, O.; Walden, P.

2011-10-01

49

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

50

Indirect evidence for elastic energy playing a role in limb recovery during toad hopping.  

PubMed

Elastic energy is critical for amplifying muscle power during the propulsive phase of anuran jumping. In this study, we use toads (Bufo marinus) to address whether elastic recoil is also involved after take-off to help flex the limbs before landing. The potential for such spring-like behaviour stems from the unusually flexed configuration of a toad's hindlimbs in a relaxed state. Manual extension of the knee beyond approximately 90° leads to the rapid development of passive tension in the limb as underlying elastic tissues become stretched. We hypothesized that during take-off, the knee regularly extends beyond this, allowing passive recoil to help drive limb flexion in mid-air. To test this, we used high-speed video and electromyography to record hindlimb kinematics and electrical activity in a hindlimb extensor (semimembranosus) and flexor (iliofibularis). We predicted that hops in which the knees extended further during take-off would require less knee flexor recruitment during recovery. Knees extended beyond 90° in over 80% of hops, and longer hops involved greater degrees of knee extension during take-off and more intense semimembranosus activity. However, knee flexion velocities during recovery were maintained despite a significant decrease in iliofibularis intensity in longer hops, results consistent with elastic recoil playing a role. PMID:25030045

Schnyer, Ariela; Gallardo, Mirialys; Cox, Suzanne; Gillis, Gary

2014-07-01

51

Elastic scattering of low-energy electrons by nitromethane  

SciTech Connect

In this work, we present integral, differential, and momentum transfer cross sections for elastic scattering of low-energy electrons by nitromethane, for energies up to 10 eV. We calculated the cross sections using the Schwinger multichannel method with pseudopotentials, in the static-exchange and in the static-exchange plus polarization approximations. The computed integral cross sections show a {pi}* shape resonance at 0.70 eV in the static-exchange-polarization approximation, which is in reasonable agreement with experimental data. We also found a {sigma}* shape resonance at 4.8 eV in the static-exchange-polarization approximation, which has not been previously characterized by the experiment. We also discuss how these resonances may play a role in the dissociation process of this molecule.

Lopes, A. R.; D'A Sanchez, S.; Bettega, M. H. F. [Departamento de Fisica, Universidade Federal do Parana, Caixa Postal 19044, 81531-990 Curitiba, Parana (Brazil)

2011-06-15

52

Phenomenological optical potential analysis of proton-carbon elastic scattering at 200 MeV  

NASA Technical Reports Server (NTRS)

Differential cross sections for 200 MeV protons elastically scattered from C-12 were analyzed utilizing a local, complex, spin-dependent optical potential with a harmonic well radial dependence. Analyses were performed using the WKB and eikonal approximations. For the latter, first-order corrections to he phase shifts were incorporated to account for the spin-orbit contribution. Large disagreement between theory and experiment was observed when the usual Thomas form for the spin-orbit potential was utilized. Substantial improvement was obtained by allowing the parameters in the central and spin-orbit potential terms to vary independently.

Bidasaria, H. B.; Townsend, L. W.

1982-01-01

53

LETTER doi:10.1038/nature12267 Elastic energy storage in the shoulder and the  

E-print Network

angular movements that accumulate kinetic energy in the projectile until its release. It has been shown#12;LETTER doi:10.1038/nature12267 Elastic energy storage in the shoulder and the evolution of high elastic energy storage and release at the shoulder. These features first appear together approximately 2

Udgaonkar, Jayant B.

54

LETTER doi:10.1038/nature12267 Elastic energy storage in the shoulder and the  

E-print Network

angular movements that accumulate kinetic energy in the projectile until its release. It has been shownLETTER doi:10.1038/nature12267 Elastic energy storage in the shoulder and the evolution of high elastic energy storage and release at the shoulder. These features first appear together approximately 2

Lieberman, Daniel E.

55

Elastic energy release due to domain formation in the strained epitaxy of ferroelectric and ferroelastic films  

E-print Network

Elastic energy release due to domain formation in the strained epitaxy of ferroelectric and multiple domain fields depending on the relative misfit strains and domain wall energy. The concept strain between the substrate and ftlm and the ratio of the domain wall energy to the stored elastic

Suo, Zhigang

56

Low-energy elastic electron scattering from furan  

SciTech Connect

We report normalized experimental and theoretical differential cross sections for elastic electron scattering by C{sub 4}H{sub 4}O (furan) molecules from a collaborative project between several Brazilian theoretical groups and an experimental group at California State Fullerton, USA. The measurements are obtained by using the relative flow method with helium as the standard gas and a thin aperture target gas collimating source. The relative flow method is applied without the restriction imposed by the relative flow pressure condition on helium and the unknown gas. The experimental data were taken at incident electron energies of 1, 1.5, 1.73, 2, 2.7, 3, 5, 7, 10, 20, 30, and 50 eV and covered the angular range between 10 deg. and 130 deg. The measurements verify observed {pi}* shape resonances at 1.65{+-}0.05eV and 3.10{+-}0.05 eV scattering energies, in good agreement with the transmission electron data of Modelli and Burrow [J. Phys. Chem. A 108, 5721 (2004)]. Furthermore, the present results also indicated both resonances dominantly in the d-wave channel. The differential cross sections are integrated in the standard way to obtain integral elastic cross sections and momentum transfer cross sections. The calculations employed the Schwinger multichannel method with pseudopotentials and were performed in the static-exchange and in the static-exchange plus polarization approximations. The calculated integral and momentum transfer cross sections clearly revealed the presence of two shape resonances located at 1.95 and 3.56 eV and ascribed to the B{sub 1} and A{sub 2} symmetries of the C{sub 2v} point group, respectively, in very good agreement with the experimental findings. Overall agreement between theory and experiment regarding the differential, momentum transfer, and integral cross sections is very good, especially for energies below 10 eV.

Khakoo, M. A.; Muse, J.; Ralphs, K. [Department of Physics, California State University, Fullerton, California 92834 (United States); Costa, R. F. [Centro de Ciencias Naturais e Humanas, Universidade Federal do ABC, 09210-170 Santo Andre, Sao Paulo (Brazil); Bettega, M. H. F. [Departamento de Fisica, Universidade Federal do Parana, Caixa Postal 19044, 81531-990 Curitiba, Parana (Brazil); Lima, M. A. P. [Instituto de Fisica Gleb Wataghin, Universidade Estadual de Campinas, Caixa Postal 6165, 13083-970 Campinas, Sao Paulo (Brazil); Laboratorio Nacional de Ciencia e Tecnologia do Bioetanol (CTBE), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM), Caixa Postal 6170, 13083-970 Campinas, Sao Paulo (Brazil)

2010-06-15

57

Biomass Energy Crops: Massachusetts' Potential  

E-print Network

Biomass Energy Crops: Massachusetts' Potential Prepared for: Massachusetts Division of Energy;#12;Executive Summary In Massachusetts, biomass energy has typically meant wood chips derived from the region's extensive forest cover. Yet nationally, biomass energy from dedicated energy crops and from crop residues

Schweik, Charles M.

58

Elastic Scattering Of 6,7Li+80Se At Near And Above Barrier Energies  

NASA Astrophysics Data System (ADS)

In this work we propose to study the elastic scattering of the weakly bound projectiles 6,7Li on an intermediate mass target 80Se. From the experimental results presented here, precise angular distributions at energies below, around and above the nominal Coulomb barriers of the systems were obtained. The final goal of our work is to determine the characteristic parameters of the optical potential and use them to address the question of whether the usual threshold anomaly or the breakup threshold anomaly are present or not in these systems.

Fimiani, L.; Martí, G. V.; Arazi, A.; Capurro, O. A.; Cardona, M. A.; Carnelli, P.; de Barbará, E.; Fernández Niello, J. O.; Figueira, J. M.; Hojman, D.; Martinez Heimann, D.; Negri, A. E.; Pacheco, A. J.; Testoni, J. E.; Zalazar, L.

2010-08-01

59

Elastic scattering of low-energy positrons by bound silicon and germanium  

NASA Astrophysics Data System (ADS)

Elastic scattering differential and total cross sections for low-energy positron collisions with bound silicon and germanium atoms have been computed using partial wave analysis with static and polarization potentials. The calculations are performed at incident positron energies ranging from 0.2 to 500 eV. For each impact energy, an appropriate number of phase shifts are obtained by numerically integrating the radial wave equation to ensure convergence of the scattering amplitude. A simple parametrization of the total cross section in terms of the screened Rutherford cross section is also presented for use in Monte Carlo codes. Due, in part, to the lack of reliable experimental data, relatively little theoretical work has been done to calculate the inelastic and elastic differential cross sections (DCS) and total cross sections (TCS) for positron scattering. Most of the measurements were made on noble gases where it is observed that low-energy positrons exhibit a Ramsauer-Townsend (RT) minimum for helium, neon, and possibly argon (for electrons, the RT minimum occurs for heavier noble gases).1,2 Calculations of the positron TCS for these atoms agree with the observations. The RT effect has also been identified in a number of other free atoms and molecules for electrons.3,4 Recently, Meredith et al. computed the electron elastic scattering cross sections in solid silicon and germanium.5 In this work we calculate the DCS and TCS for positrons elastically scattered by silicon and germanium atoms which are bound in an amorphous solid using partial waves and the optical model. The results are presented for incident positron energies ranging from 0.2 to 500 eV. Simple fits to each TCS are given for use in Monte Carlo scattering simulations. For the static potential VS, Salvat and Parellada used Dirac-Hartree-Fock-Slater (DHFS) calculations to accurately fit analytic screening functions for atoms.6 They also imposed Wigner-Seitz boundary conditions (WSBC) on their wave functions to simulate atoms bound in a solid. The functional form of the static potential is (in atomic units)

Antolak, A. J.; Williamson, W., Jr.

1991-03-01

60

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. PMID:19321153

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

2009-01-01

61

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

62

Inertia-sensitive impact energy-absorbing structures part I: Effects of inertia and elasticity  

Microsoft Academic Search

By assuming an elastic-perfectly plastic constitutive relation for the material and employing a model which consists of four compressible elastic-plastic bars connected by four elastic-plastic “hinges” of finite length, the dynamic behaviour of an inertia-sensitive impact energy-absorbing structure (previously called a Type II structure) under impact is analysed in detail. By taking account of the complicated deformation history involving loading,

X. Y. Su; T. X. Yu; S. R. Reid

1995-01-01

63

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

64

Contribution to the theory of tidal oscillations of an elastic earth. External tidal potential  

NASA Technical Reports Server (NTRS)

The differential equations of the tidal oscillations of the earth were established under the assumption that the interior of the earth is laterally inhomogeneous. The theory was developed using vectorial and dyadic symbolism to shorten the exposition and to reduce the differential equations to a symmetric form convenient for programming and for numerical integration. The formation of tidal buldges on the surfaces of discontinuity and the changes in the internal density produce small periodic variations in the exterior geopotential which are reflected in the motion of artificial satellites. The analoques of Love elastic parameters in the expansion of exterior tidal potential reflect the asymmetric and inhomogeneous structure of the interior of the earth.

Musen, P.

1974-01-01

65

Coda wave interferometry and the equilibration of energy in elastic media Roel Snieder  

E-print Network

Coda wave interferometry and the equilibration of energy in elastic media Roel Snieder Department 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

Snieder, Roel

66

CAPITAL FOR ENERGY AND INTER-FUEL ELASTICITIES OF SUBSTITUTION  

E-print Network

: ESTIMATING THE COST OF GREENHOUSE GAS REDUCTION Prepared for: Natural Resources Canada Prepared by to make a cost comparison of potential greenhouse gas (GHG) abatement policies. Our primary tools: Christopher G.F. Bataille Energy Research Group School of Resource and Environmental Management Simon Fraser

67

Pole structure from energy-dependent and single-energy fits to $?N$ elastic scattering data  

E-print Network

The pole structure of the current GW/SAID partial-wave analysis of elastic $\\pi N$ scattering and $\\eta N$ production data is studied. Pole positions and residues are extracted from both the energy-dependent and single-energy fits, using two different methods. For the energy-dependent fits, both contour integration and a Laurent+Pietarinen approach are used. In the case of single-energy fits, the Laurent+Pietarinen approach is used. Errors are estimated and the two sets of results are compared to other recent and older fits to data.

Alfred Švarc; Mirza Hadžimehmedovi?; Hedim Osmanovi?; Jugoslav Stahov; Ron L. Workman

2014-05-26

68

A critical assessment of interatomic potentials for ceria with application to its elastic properties  

Microsoft Academic Search

We critically assess the materials fidelity of six interatomic potentials for ceria, based on predicted lattice constants, thermal expansion, chemical expansion, dielectric properties, oxygen migration energy and mechanical properties. While, no potential can reproduce all fundamental properties, the Gotte (2007) and Grimes potentials display the combination of highest fidelity with the widest range of applicability. The simulations show that sub-stoichiometry

Rakesh K. Behera; Fereshteh Ebrahimi; Susan B. Sinnott; Eric D. Wachsman; Simon R. Phillpot

2010-01-01

69

Radial Sensitivity of the Elastic Scattering around the Coulomb Barrier Energies for Weakly-Bound and Halo Nuclei  

NASA Astrophysics Data System (ADS)

The radial sensitivity of the elastic scattering of the weakly-bound 6Li and halo 6He nuclei on medium-mass 64Zn target and heavy target 208Pb is examined around the Coulomb barrier energies. We present that very good agreement between theoretical and experimental results have been obtained with small ?2/N values. The fusion cross-section and volume integrals of the potentials have been deduced from the theoretical calculations for all studied systems at relevant energies. We have also analyzed the elastic scattering of the 6He+208Pb system at Elab = 14, 16, 18, 22, 27 MeV in order to investigate whether there is a dispersion relation between the real and imaginary parts of the optical potential.

Sert, Y.; Caner, T.; Bayrak, O.; Boztosun, I.

2012-07-01

70

Parton-parton elastic scattering and rapidity gaps at SSC and LHC energies  

SciTech Connect

The theory of the perturbative pomeron, due to Lipatov and collaborators, is used to compute the probability of observing parton-parton elastic scattering and rapidity gaps between jets in hadron collisions at SSC and LHC energies.

Duca, V.D.

1993-08-01

71

Parton-parton elastic scattering and rapidity gaps at Tevatron energies  

SciTech Connect

The theory of the perturbative pomeron, due to Lipatov and collaborators, is used to compute the probability of observing parton-parton elastic scattering and rapidity gaps between jets in hadron collisions at Tevatron energies.

Del Duca, V.; Tang, Wai-Keung

1993-08-01

72

LHC Predictions from an extended theory with Elastic, Inelastic, and Path Length Fluctuating Energy Loss  

E-print Network

We present the LHC predictions for the WHDG model of radiative, elastic, and path length fluctuating energy loss. We find the pT dependence of RAA is qualitatively very different from AWS-based energy loss extrapolations to the LHC; the large pT reach of the year one data at the LHC should suffice to distinguish between the two. We also discuss the importance of requiring a first elastic scatter before any medium-induced elastic or radiative loss occurs, a necessary physical effect not considered in any previous models.

William A. Horowitz

2007-02-27

73

Energy elastic effects and the concept of temperature in flowing polymeric liquids  

Microsoft Academic Search

The incorporation of energy elastic effects in the modeling of flowing polymeric liquids is discussed. Since conformational\\u000a energetic effects are determined by structural features much smaller than the end-to-end vector of the polymer chains, commonly\\u000a employed single conformation tensor models are insufficient to describe energy elastic effects. The need for a local structural\\u000a variable is substantiated by studying a microscopic

Markus Hütter; Clarisse Luap; Hans Christian Öttinger

2009-01-01

74

An elastic energy approach to the interstitial diffusion of 3d elements in silicon  

Microsoft Academic Search

Evidence is presented that the elastic energy contribution to the migration enthalpies of interstitially dissolved 3d atoms in silicon cannot be neglected. The difference in elastic energy at the tetrahedral interstitial and the hexagonal interstitial site has been estimated in a hard-sphere model. The preexponential factor of diffusion D0 is evaluated within the framework of Zener’s D0 theory [C. Zener,

J. Utzig

1989-01-01

75

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

76

An aero-elastic flutter based electromagnetic energy harvester with wind speed augmenting funnel  

E-print Network

An aero-elastic flutter based electromagnetic energy harvester with wind speed augmenting funnel been used to convert wind flow energy into mechanical vibration, which is then transformed-scale renewable energy generating systems such as wind turbines, thermal generators, and solar panels, energy

Stanford University

77

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

78

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

79

Elastic energy of a deformable earth: General expression  

Microsoft Academic Search

This work is the first in the second part of a project dedicated to elaborating a Hamiltonian theory for the rotational motion of a deformable Earth. In the four works which make up the first part the basis of this theory is laid down, studying the effects produced when the Earth's elastic mantle is deformed by lunisolar attraction. More specifically,

Juan Getino; Facultad Ciencias

1992-01-01

80

Salinity Effects on Water Potential Components and Bulk Elastic Modulus of Alternanthera philoxeroides (Mart.) Griseb.  

PubMed

Pressure volume curves for Alternanthera philoxeroides (Mart.) Griseb. (alligator weed) grown in 0 to 400 millimolar NaCl were used to determine water potential (Psi), osmotic potential (psi(s)), turgor potential (psi(p)) and the bulk elastic modulus (epsilon) of shoots at different tissue water contents. Values of psi(s) decreased with increasing salinity and tissue Psi was always lower than rhizosphere Psi. The relationship between psi(p) and tissue water content changed because epsilon increased with salinity. As a result, salt-stressed plants had larger ranges of positive turgor but smaller ranges of tissue water content over which psi(p) was positive. To our knowledge, this is the first report of such a salinity effect on epsilon in higher plants. These increases in epsilon 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 within 1 day, psi(s) and psi(p) continued to change for 2 to 4 days, and epsilon continued to change for 4 to 12 days. Changes in epsilon 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. PMID:16663611

Bolaños, J A; Longstreth, D J

1984-06-01

81

Salinity Effects on Water Potential Components and Bulk Elastic Modulus of Alternanthera philoxeroides (Mart.) Griseb. 1  

PubMed Central

Pressure volume curves for Alternanthera philoxeroides (Mart.) Griseb. (alligator weed) grown in 0 to 400 millimolar NaCl were used to determine water potential (?), osmotic potential (?s), turgor potential (?p) and the bulk elastic modulus (?) of shoots at different tissue water contents. Values of ?s decreased with increasing salinity and tissue ? was always lower than rhizosphere ?. The relationship between ?p and tissue water content changed because ? increased with salinity. As a result, salt-stressed plants had larger ranges of positive turgor but smaller ranges of tissue water content over which ?p was positive. To our knowledge, this is the first report of such a salinity effect on ? in higher plants. These increases in ? with salinity provided a mechanism by which a large difference between plant ? and rhizosphere ?, 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 ? was constant within 1 day, ?s and ?p continued to change for 2 to 4 days, and ? continued to change for 4 to 12 days. Changes in ? 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. PMID:16663611

Bolaños, Jorge A.; Longstreth, David J.

1984-01-01

82

The cross-bridge spring: can cool muscles store elastic energy?  

PubMed

Muscles not only generate force. They may act as springs, providing energy storage to drive locomotion. Although extensible myofilaments are implicated as sites of energy storage, we show that intramuscular temperature gradients may enable molecular motors (cross-bridges) to store elastic strain energy. By using time-resolved small-angle x-ray diffraction paired with in situ measurements of mechanical energy exchange in flight muscles of Manduca sexta, we produced high-speed movies of x-ray equatorial reflections, indicating cross-bridge association with myofilaments. A temperature gradient within the flight muscle leads to lower cross-bridge cycling in the cooler regions. Those cross-bridges could elastically return energy at the extrema of muscle lengthening and shortening, helping drive cyclic wing motions. These results suggest that cross-bridges can perform functions other than contraction, acting as molecular links for elastic energy storage. PMID:23618763

George, N T; Irving, T C; Williams, C D; Daniel, T L

2013-06-01

83

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

84

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

85

Price Elasticities for Energy Use in Buildings of the United States  

EIA Publications

Energy demand tends to be responsive to changes in energy prices, a concept in economics known as price elasticity. Generally, an increase in a fuel price causes users to use less of that fuel or switch to a different fuel. The extent to which each of these changes takes place is of high importance to stakeholders in the energy sector and especially in energy planning. The purpose of this analysis is to determine fuel-price elasticities in stationary structures, particularly in the residential and commercial sectors.

2014-01-01

86

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

87

Optical Potential Approach to $K^{+}d$ Scattering at Low Energies  

E-print Network

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

Takashi Takaki

2009-11-29

88

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

89

Elastic constants and phonon frequencies of Si calculated by a fast full-potential linear-muffin-tin-orbital method  

Microsoft Academic Search

A new approach for including full-potential terms in a linear-muffin-tin-orbital calculation is presented. The implementation for crystals leads to a method which is at the same time fast and accurate. Calculated elastic constants and phonon frequencies for Si agree well with experiment.

M. Methfessel

1988-01-01

90

Surface Energy as a Barrier to Creasing of Elastomer Films: An Elastic Analogy to Classical Nucleation  

E-print Network

in the failure of photo- graphic films [1], rubber tires [2], dielectric elastomer actuators [3], and biomedicalSurface Energy as a Barrier to Creasing of Elastomer Films: An Elastic Analogy to Classical are resisted by the surface energy, which we demonstrate by studying creases for elastomers immersed in several

Suo, Zhigang

91

Nuclear Elastic Scattering of Photons near the Particle Threshold Energy (II)  

Microsoft Academic Search

Elastic scattering cross section of photons by a nucleus near the particle threshold energy was studied at 120 degrees for Mg, Fe, Zn, As, Cd, Sb and Bi using bremsstrahlung gamma rays. Each element has a gross peak in this energy range. This is consistent with the earlier results reported by Tohei et al. The peak values are 0.5, 1.3,

Masumi Sugawara; Shigeki Mori; Atsuwo Ono; Akio Hotta; Motoharu Kimura

1963-01-01

92

NUCLEAR ELASTIC SCATTERING OF PHOTONS NEAR THE PARTICLE THRESHOLD ENERGY. PART II  

Microsoft Academic Search

Elastic scattering cross section of photons by a nucleus near the ; particle threshold energy was studied at 120 degrees for Mg, Fe, Zn, As, Cd, Sb. ; and Bi using bremsstrahlung gamma rays. Each element has a gross peak in this ; energy range. This is consistent with the earlier results reported by Tohei et ; al. The peak

M. Sugawara; S. Mori; A. Ono; A. Hotta; M. Kimura

1963-01-01

93

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

94

Energy dissipation associated with crack extension in an elastic-plastic material  

NASA Technical Reports Server (NTRS)

Crack extension in elastic-plastic material involves energy dissipation through the creation of new crack surfaces and additional yielding around the crack front. An analytical procedure, using a two-dimensional elastic-plastic finite element method, was developed to calculate the energy dissipation components during a quasi-static crack extension. The fracture of an isotropic compact specimen was numerically simulated using the critical crack-tip-opening-displacement (CTOD) growth criterion. Two specimen sizes were analyzed for three values of critical CTOD. Results from the analysis showed that the total energy dissipation rate consisted of three components: the crack separation energy rate, the plastic energy dissipation rate, and the residual strain energy rate. All three energy dissipation components and the total energy dissipation rate initially increased with crack extension and finally reached constant values.

Shivakumar, K. N.; Crews, J. H., Jr.

1987-01-01

95

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

96

Energies of sp2 carbon shapes with pentagonal disclinations and elasticity theory  

E-print Network

Energies of a certain class of fullerene molecules (elongated, contracted, and regular icosahedral fullerenes) are numerically calculated using a microscopic description of carbon-carbon bonding. It is shown how these results can be interpreted and comprehended using the theory of elasticity that describes bending of a graphene plane. Detailed studies of a wide variety of structures constructed by application of the same general principle are performed, and analytical expressions for energies of such structures are derived. Comparison of numerical results with the predictions of a simple implementation of elasticity theory confirms the usefulness of the latter approach.

Antonio Siber

2006-03-28

97

cap alpha. /sup 4/He elastic scattering at high energies  

SciTech Connect

Differential cross sections for ..cap alpha.. /sup 4/He elastic scattering have been calculated at incident ..cap alpha..-particle momenta of 4.32, 5.07, and 7.0 GeV/c within the framework of Glauber multiple scattering theory. The full Glauber amplitude has been calculated using the Monte Carlo method for evaluating multidimensional integrals. We found that, in general, the more realistic double-Gaussian model for the density brings theory closer to experiment as compared to the generally used single-Gaussian model in some momentum transfer regions. Our results with the double-Gaussian model and an acceptable set of NN parameters are in fairly good agreement with the experimental data at 4.32 and 5.07 GeV/c.

Usmani, A.A.; Ahmad, I.; Usmani, Q.N.

1989-03-01

98

The potential of renewable energy  

SciTech Connect

On June 27 and 28, 1989, the US Department of Energy (DOE) national laboratories were convened to discuss plans for the development of a National Energy Strategy (NES) and, in particular, the analytic needs in support of NES that could be addressed by the laboratories. As a result of that meeting, interlaboratory teams were formed to produce analytic white papers on key topics, and a lead laboratory was designated for each core laboratory team. The broad-ranging renewables assignment is summarized by the following issue statement from the Office of Policy, Planning and Analysis: to what extent can renewable energy technologies contribute to diversifying sources of energy supply What are the major barriers to greater renewable energy use and what is the potential timing of widespread commercialization for various categories of applications This report presents the results of the intensive activity initiated by the June 1989 meeting to produce a white paper on renewable energy. Scores of scientists, analysts, and engineers in the five core laboratories gave generously of their time over the past eight months to produce this document. Their generous, constructive efforts are hereby gratefully acknowledged. 126 refs., 44 figs., 32 tabs.

Not Available

1990-03-01

99

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

100

High energy proton-proton elastic scattering at the Large Hadron Collider and nucleon structure  

NASA Astrophysics Data System (ADS)

To gain insight into the structure of the nucleon, we pursue the development of the phenomenological model of Islam et al. (IIFS model) for high energy elastic pp and p¯p scattering. We determine the energy dependence of the parameters of the IIFS model using the available elastic differential cross section data from SPS Collider and Tevatron and the known asymptotic behavior of sigmatot (s) and rho(s) from dispersion relation calculations and more recent analyses of Cudell et al. (COMPETE Collaboration). Next, we incorporate a high energy elastic valence quark-quark scattering amplitude into the model based on BFKL pomeron to describe small impact parameter (large | t|) pp collisions. Finally, we predict the pp elastic differential cross section at the unprecedented c.m. energy of s = 14.0 TeV at the Large Hadron Collider (LHC). This prediction assumes crucial significance---because of an approved experiment at LHC: TOTal and Elastic Measurement (TOTEM). The TOTEM group plans to measure pp elastic dsigma/dt at 14.0 TeV all the way from momentum transfer |t| = 0 to |t| ? 10 GeV 2. Their measurement will stringently test not only the diffraction and o-exchange descriptions of the original IIFS model, but also the additional valence quark-quark scattering contribution that we find to be dominant for large |t|. Successful quantitative verification of the predicted dsigma/dt will mean that our picture of the nucleon with an outer cloud of qq¯ condensed ground state, an inner core of topological baryonic charge, and a still smaller core of massless valence quarks provides a realistic description of nucleon structure.

Luddy, Richard Joseph

101

Elastic Scattering Of {sup 6,7}Li+{sup 80}Se At Near And Above Barrier Energies  

SciTech Connect

In this work we propose to study the elastic scattering of the weakly bound projectiles {sup 6,7}Li on an intermediate mass target {sup 80}Se. From the experimental results presented here, precise angular distributions at energies below, around and above the nominal Coulomb barriers of the systems were obtained. The final goal of our work is to determine the characteristic parameters of the optical potential and use them to address the question of whether the usual threshold anomaly or the breakup threshold anomaly are present or not in these systems.

Fimiani, L.; Marti, G. V.; Capurro, O. A.; Barbara, E. de; Testoni, J. E.; Zalazar, L. [Laboratorio TANDAR, Comision Nacional de Energia Atomica, Av. Gral. Paz 1499 B1650KNA, San Martin (Argentina); Arazi, A.; Cardona, M. A.; Carnelli, P.; Figueira, J. M.; Hojman, D.; Martinez Heimann, D.; Negri, A. E.; Pacheco, A. J. [Laboratorio TANDAR, Comision Nacional de Energia Atomica, Av. Gral. Paz 1499 B1650KNA, San Martin (Argentina); CONICET, Av. Rivadavia 1917, C1033AAJ Buenos Aires (Argentina); Fernandez Niello, J. O. [Laboratorio TANDAR, Comision Nacional de Energia Atomica, Av. Gral. Paz 1499 B1650KNA, San Martin (Argentina); CONICET, Av. Rivadavia 1917, C1033AAJ Buenos Aires (Argentina); Universidad Nacional de General San Martin, Ayacucho 2197, B1650BWA San Martin (Argentina)

2010-08-04

102

NUCLEAR ELASTIC SCATTERING OF PHOTONS NEAR THE PARTICLE THRESHOLD ENERGY PART I  

Microsoft Academic Search

The elastic scattering of photons near the particle threshold energy was ; studied for Al, Si, S, K, Ca, Ni, Cu, Cd, Sn, Pb, and Bi. The bremsstrahlung x ; rays from a 25 Mev betatron were used. The pulse of the primary x rays was ; expanded up to about 30 mu sec to decrease the pile-up effect. The

T. Tohei; M. Sugawara; S. Mori; M. Kimura

1961-01-01

103

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

104

Performance of guinea fowl Numida meleagris during jumping requires storage and release of elastic energy  

Microsoft Academic Search

The ability of birds to perform effective jumps may play an important role in predator avoidance and flight initiation. Jumping can provide the vertical acceleration necessary for a rapid takeoff, which may be particularly important for ground-dwelling birds such as phasianids. We hypothesized that by making use of elastic energy storage and release, the leg muscles could provide the large

Havalee T. Henry; David J. Ellerby; Richard L. Marsh

2005-01-01

105

Differential cross sections for high energy elastic hadron-hadron scattering in nonperturbative QCD  

E-print Network

Total and differential cross sections for high energy and small momentum transfer elastic hadron-hadron scattering are studied in QCD using a functional integral approach. The hadronic amplitudes are governed by vacuum expectation values of lightlike Wegner-Wilson loops, for which a matrix cumulant expansion is derived. The cumulants are evaluated within the framework of the Minkowskian version of the model of the stochastic vacuum. Using the second cumulant, we calculate elastic differential cross sections for hadron-hadron scattering. The agreement with experimental data is good.

E. R. Berger; O. Nachtmann

1998-08-13

106

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

107

Elastic constants of defected and amorphous silicon with the environment-dependent interatomic potential  

E-print Network

concentration of 0.3%. (2) The linear effect of Frenkel pairs on the 110 Young's modulus of silicon is -1653 GPa in the typical case in which point-defect concentrations can be estimated, but the exact distribution and speciesElastic constants of defected and amorphous silicon with the environment-dependent interatomic

Bazant, Martin Z.

108

Non-Monotonic - and 6Li-POTENTIALS from Energy Density Functional Formalism  

NASA Astrophysics Data System (ADS)

The present status of the ?-nucleus potential, generated from the energy density functional (EDF) formalism using a realistic two-nucleon potential, which incorporates the Pauli principle, is discussed. The EDF potentials, calculated using a density distribution of ?-particle that yields a binding energy of 20 MeV with a reasonable root-mean-squared radius and observed density distributions of 6Li and various target nuclei, are found to be shallow and non-monotonic in character. This non-monotonic EDF potential reproduces satisfactorily the experimental elastic scattering data, particularly at energies above the Coulomb barrier. Since the elastic scattering data and the binding energies of all nuclei considered herein are well reproduced using the mean field generated from a realistic two-nucleon potential for nuclear and nucleonic matter, one may conclude to have reasonable information on the equation of states of nuclear and nucleonic matter from a very low to the saturation density from the present investigation.

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

2009-12-01

109

Hybrid Simulation Modeling to Estimate U.S. Energy Elasticities  

E-print Network

energy efficiency index (AEEI) parameters. The ability of economies to reduce greenhouse gas emissions rights reserved. However, in accordance with the Copyright Act of Canada, this work may be reproduced of this work for the purposes of private study, research, criticism, review and news reporting is likely

110

Microscopic study on proton elastic scattering of helium and lithium isotopes at energy range up to 160 MeV/nucleon.  

NASA Astrophysics Data System (ADS)

The proton elastic scattering data on 4,6,8 He and 6,7,9,11Li nuclei at energies below 160 MeV/nucleon are analyzed using the optical model. The optical potential (OP) is taken microscopically, with few and limited fitting parameters, using the single folding model for the real part and high-energy approximation (HEA) for the imaginary one. Clear dependencies of the volume integrals on energy and rms radii are obtained from the results. The calculated differential and the reaction cross sections are in good agreement with the available experimental data. In general, this OP with few and limited fitting parameters, which have a systematic behavior with incident energy and matter radii, successfully describes the proton elastic scattering data with stable and exotic light nuclei at energies up to 160 MeV/nucleon.

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

2014-03-01

111

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

112

Microscopic positive-energy potential based on Gogny interaction  

E-print Network

We present nucleon elastic scattering calculation based on Green's function formalism in the Random-Phase Approximation. For the first time, the Gogny effective interaction is used consistently throughout the whole calculation to account for the complex, non-local and energy-dependent optical potential. Effects of intermediate single-particle resonances are included and found to play a crucial role in the account for measured reaction cross section. Double counting of the particle-hole second-order contribution is carefully addressed. The resulting integro-differential Schr\\"odinger equation for the scattering process is solved without localization procedures. The method is applied to neutron and proton elastic scattering from $^{40}$Ca. A successful account for differential and integral cross sections, including analyzing powers, is obtained for incident energies up to 30 MeV. Discrepancies at higher energies are related to much too high volume integral of the real potential for large partial waves. Moreover, this works opens the way for future effective interactions suitable simultaneously for both nuclear structure and reaction.

G. Blanchon; M. Dupuis; H. F. Arellano; N. Vinh Mau

2014-10-28

113

Potential of geothermal energy in China  

E-print Network

This thesis provides an overview of geothermal power generation and the potential for geothermal energy utilization in China. Geothermal energy is thermal energy stored in the earth's crust and currently the only ubiquitously ...

Sung, Peter On

2010-01-01

114

Elastic Scattering of Low-Energy Electrons byTetrahydrofuran  

SciTech Connect

We present the results of ab initio calculations for elasticelectron scattering by tetrahydrofuran (THF) using the complex Kohnvariational method. We carried out fixed-nuclei calculations at theequilibrium geometry of the target molecule for incident electronenergies up to 20 eV. The calculated momentum transfer cross sectionsclearly reveal the presence of broad shape resonance behavior in the 8-10eV energy range, in agreement with recent experiments. The calculateddifferential cross sections at 20 eV, which include the effects of thelong-range electron-dipole interaction, are alsofound to be in agreementwith the most recent experimental findings.

Trevisan, Cynthia S.; Orel, Ann E.; Rescigno, Thomas N.

2006-05-09

115

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. PMID:24744905

Nakamura, Yoshihiro; Awa, Shoichi

2014-01-01

116

Remarks on the energy release rate for an antiplane moving crack in couple stress elasticity  

E-print Network

This paper is concerned with the steady-state propagation of an antiplane semi-infinite crack in couple stress elastic materials. A distributed loading applied at the crack faces and moving with the same velocity of the crack tip is considered, and the influence of the loading profile variations and microstructural effects on the dynamic energy release rate is investigated. The behaviour of both energy release rate and maximum total shear stress when the crack tip speed approaches the critical speed (either that of the shear waves or that of the localised surface waves) is studied. The limit case corresponding to vanishing characteristic scale lengths is addressed both numerically and analytically by means of a comparison with classical elasticity results.

L. Morini; A. Piccolroaz; G. Mishuris

2013-11-21

117

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

118

Low-energy electron elastic scattering from Mn, Cu, Zn, Ni, Ag, and Cd atoms  

SciTech Connect

Electron elastic total cross sections (TCSs) for ground and excited Mn, Cu, Zn, Ni, Ag, and Cd atoms have been investigated in the electron-impact energy range 0 {<=}E{<=} 1 eV. The near-threshold TCSs for both the ground and excited states of these atoms are found to be characterized by Ramsauer-Townsend minima, shape resonances, and extremely sharp resonances corresponding to the formation of stable bound negative ions. The recently developed Regge-pole methodology where the crucial electron-electron correlations are embedded is employed for the calculations. From close scrutiny of the imaginary parts of the complex angular momenta, we conclude that these atoms form stable weakly bound ground and excited negative ions as Regge resonances through slow electron collisions. The extracted electron binding energies from the elastic TCSs of these atoms are contrasted with the available experimental and theoretical values.

Felfli, Z.; Msezane, A. Z. [Department of Physics and Center 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)

2011-05-15

119

Nuclear Elastic Scattering of Photons near the Particle Threshold Energy (I)  

Microsoft Academic Search

The elastic scattering of photons near the particle threshold energy was studied for Al, Si, S, K, Ca, Ni, Cu, Cd, Sn, Pb and Bi. The bremsstrahlung x-rays from a 25 Mev betatron were used. The pulse of the primary x-rays was expanded up to about 30 mu sec to decrease the pile-up effect. The scattered photons were detected at

Tsutomu Tohei; Masumi Sugawara; Shigeki Mori; Motoharu Kimura

1961-01-01

120

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

121

Finite element formulation using magnetic vector potential approach: effects of displacement current in magneto-electro-elastic cylindrical shells  

NASA Astrophysics Data System (ADS)

Displacement current is associated with the generation of magnetic fields due to time-varying electric fields. The harmonic response of a magneto-electro-elastic axisymmetric cylinder accounting for displacement current is carried out using the semi-analytical finite element method. The non-conservative electric field is represented using a magnetic vector potential. Studies are carried out for the first circumferential harmonics of the shell structure with the clamped-free boundary condition. The contribution made to the magnetic flux density by the electric displacement current is very small at lower frequencies but it becomes significant at higher frequencies.

Biju, B.; Ganesan, N.; Shankar, K.

2010-01-01

122

Elastic Strain Energy Storage and Neighboring Organ Assistance for Fluid Propulsion  

NASA Astrophysics Data System (ADS)

Storage of elastic strain energy by non-muscular structures such as tendons and ligaments, is a common scheme employed by jumping animals. Also, since skeletal muscle is attached to bone, mechanical advantage is obtained, allowing a burst of power that is unobtainable by muscle contraction alone. This is important at launch since force may be applied for only the brief period when the legs are in contact with the ground. Liquid propelling structures such as the urinary bladder and the heart face the similar problem of being able to impart force to the content only as long as the wall is in a stretched state. Using data from videocystometry and cardiac catheterisation we show that the means employed to achieve liquid propulsion appears to involve a combination of isometric contraction (contraction against a closed sphincter or valve) with hyperelastic stretch of the wall, elastic strain energy storage by the wall, overshoot past the undistended state and neighboring organ assistance (NOA). Thus, the heart, a partially collapsible thick muscular shell without the benefit of NOA manages an ejection fraction of about 70%. Using all of the above means, the collapsible urinary bladder is able to nearly always empty. Elastic strain energy storage and NOA appear to be important strategies for liquid propulsion employed by hollow viscera.

Arun, C. P.

2003-11-01

123

Energy dependence of nucleon-nucleon potentials  

E-print Network

We investigate the energy dependence of potentials defined through the Bethe-Salpeter wave functions. We analytically evaluate such a potential in the Ising field theory in 2 dimensions and show that its energy dependence is weak at low energy. We then numerically calculate the nucleon-nucleon potential at non-zero energy using quenched QCD with anti-periodic boundary condition. In this case we also observe that the potentials are almost identical at $E\\simeq 0$ and $E\\simeq 50$ MeV, where $E$ is the center of mass kinetic energy.

Sinya Aoki; Janos Balog; Tetsuo Hatsuda; Noriyoshi Ishii; Keiko Murano; Hidekatsu Nemura; Peter Weisz

2008-12-03

124

Energy from Forest Biomass: Potential Economic Impacts  

E-print Network

Energy from Forest Biomass: Potential Economic Impacts in Massachusetts Prepared for: Massachusetts Bioenergy Initiative, a multifaceted study of biomass energy potential in Massachusetts. The economic impact study looks specifically at impacts in the 5 western counties of the Commonwealth, where biomass energy

Schweik, Charles M.

125

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

SciTech Connect

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=200-300 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 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 {sup 12}C+{sup 12}C system in the energy range of E/A=100-400 MeV. 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. [Yukawa Institute for Theoretical Physics, Kyoto University, Kyoto 606-8502 (Japan) and RIKEN Nishina Center, Wako, Saitama 351-0198 (Japan); Department of Physics, Osaka City University, Osaka 558-8585 (Japan) and RIKEN Nishina Center, RIKEN, Wako, Saitama 351-0198 (Japan); Physics Section, Tsuru University, Tsuru, Yamanashi 402-8555 (Japan)

2010-10-15

126

Muscle-tendon interaction and elastic energy usage in human walking.  

PubMed

The present study was designed to explore how the interaction between the fascicles and tendinous tissues is involved in storage and utilization of elastic energy during human walking. Eight male subjects walked with a natural cadence (1.4 +/- 0.1 m/s) on a 10-m-long force plate system. In vivo techniques were employed to record the Achilles tendon force and to scan real-time fascicle lengths for two muscles (medial gastrocnemius and soleus). The results showed that tendinous tissues of both medial gastrocnemius and soleus muscles lengthened slowly throughout the single-stance phase and then recoiled rapidly close to the end of the ground contact. However, the fascicle length changes demonstrated different patterns and amplitudes between two muscles. The medial gastrocnemius fascicles were stretched during the early single-stance phase and then remained isometrically during the late-stance phase. In contrast, the soleus fascicles were lengthened until the end of the single-stance phase. These findings suggest that the elastic recoil takes place not as a spring-like bouncing but as a catapult action in natural human walking. The interaction between the muscle fascicles and tendinous tissues plays an important role in the process of release of elastic energy, although the leg muscles, which are commonly accepted as synergists, do not have similar mechanical behavior of fascicles in this catapult action. PMID:15845776

Ishikawa, Masaki; Komi, Paavo V; Grey, Michael J; Lepola, Vesa; Bruggemann, Gert-Peter

2005-08-01

127

Evidence for a vertebrate catapult: elastic energy storage in the plantaris tendon during frog jumping.  

PubMed

Anuran jumping is one of the most powerful accelerations in vertebrate locomotion. Several species are hypothesized to use a catapult-like mechanism to store and rapidly release elastic energy, producing power outputs far beyond the capability of muscle. Most evidence for this mechanism comes from measurements of whole-body power output; the decoupling of joint motion and muscle shortening expected in a catapult-like mechanism has not been demonstrated. We used high-speed marker-based biplanar X-ray cinefluoroscopy to quantify plantaris muscle fascicle strain and ankle joint motion in frogs in order to test for two hallmarks of a catapult mechanism: (i) shortening of fascicles prior to joint movement (during tendon stretch), and (ii) rapid joint movement during the jump without rapid muscle-shortening (during tendon recoil). During all jumps, muscle fascicles shortened by an average of 7.8 per cent (54% of total strain) prior to joint movement, stretching the tendon. The subsequent period of initial joint movement and high joint angular acceleration occurred with minimal muscle fascicle length change, consistent with the recoil of the elastic tendon. These data support the plantaris longus tendon as a site of elastic energy storage during frog jumping, and demonstrate that catapult mechanisms may be employed even in sub-maximal jumps. PMID:22090204

Astley, Henry C; Roberts, Thomas J

2012-06-23

128

A method to estimate the elastic energy stored in braided DNA molecules using hydrodynamic equations  

PubMed Central

We present a single-molecule method for measuring the torque exerted by braided DNA molecules undergoing spontaneous unbraiding while attached to a paramagnetic dumbbell in the absence of external manipulation. A magnetic tweezers setup is employed to braid pairs of lambda DNA molecules covalently bound to a surface. Upon removing the magnetic field, the braided DNA molecules undergo spontaneous unbraiding, efficiently transforming the stored elastic energy into enough mechanical energy to rotate the tethered dumbbells for periods as long as 30 minutes. Using hydrodynamic equations we estimate the torque exerted on the dumbbells by the DNA braids, yielding values ranging from 47 to 166 pN nm. PMID:21765578

Fernández-Sierra, Mónica; Delgado-Martí, Violeta; Colón-García, Jorge E.; Quiñones, Edwin

2011-01-01

129

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

130

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

131

Numerical simulations for width fluctuations in compound elastic and inelastic scattering at low energies  

SciTech Connect

The statistical theories - the Hauser-Feshbach model with the width fluctuation correction - play a central role in studying nuclear reactions in the fast energy region, hence the statistical model codes are essential for the nuclear data evaluations nowadays. In this paper, we revisit issues regarding the statistical model calculations in the fast energy range, such as the inclusion of the direct channels, and the energy averaged cross sections using different statistical assumptions. Although they have been discussed for a long time, we need more precise quantitative investigations to understand uncertainties coming from the models deficiencies in the fast energy range. For example, the partition of compound formation cross section into the elastic and inelastic channels depends on the elastic enhancement factor calculated from the statistical models. In addition, unitarity of S-matrix constrains this partition when the direct reactions are involved. Practically some simple assumptions, which many nuclear reaction model codes adopt, may work reasonably for the nuclear data evaluations. However, the uncertainties on the evaluated cross sections cannot go lower than the model uncertainty itself. We perform numerical simulations by generating the resonances using the R-matrix theory, and compare the energy (ensemble) averaged cross sections with the statistical theories, such as the theories of Moldauer, HRTW (Hofmann, Richert, Tepel, and Weidenmueller), KKM (Kawai-Kerman-McVoy), and GOE (Gaussian orthogonal ensemble).

Kawano, Toshihiko [Los Alamos National Laboratory; Talou, Patrick [Los Alamos National Laboratory

2012-09-18

132

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

133

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

134

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

135

Gurson-type elastic-plastic damage model based on strain-rate plastic potential  

NASA Astrophysics Data System (ADS)

Ductile damage is generally described by stress-space analytical potentials. In this contribution, it is shown that strain rate potentials, which are exact conjugate of the stress-based potentials, can be equally used to describe the dilatational response of porous metals. This framework is particularly appropriate for porous materials with matrix described by complex yield criteria for which a closed-form expression of the stress-based potential is not available. Illustration of the new approach is done for porous metals containing randomly distributed spherical voids in a von Mises elasto-plastic matrix. Furthermore, a general time integration algorithm for simulation of the mechanical response using this new formulation is developed and implemented in Abaqus/Standard. The proposed model and algorithm are validated with respect to the Abaqus built-in GTN model, which is based on a stress potential, through the simulation of a tensile test on a round bar.

Balan, Tudor; Cazacu, Oana

2013-12-01

136

Energy current imaging method for time reversal in elastic media Brian E. Anderson,1,2,a  

E-print Network

Energy current imaging method for time reversal in elastic media Brian E. Anderson,1,2,a Robert A as others for fluid media, could benefit from using a higher resolution imaging method, as the one proposed 16 July 2009 An energy current imaging method is presented for use in locating sources of wave energy

137

Muscle mechanical work and elastic energy utilization during walking and running near the preferred gait transition speed  

Microsoft Academic Search

Mechanical and metabolic energy conservation is considered to be a defining characteristic in many common motor tasks. During human gait, the storage and return of elastic energy in compliant structures is an important energy saving mechanism that may reduce the necessary muscle fiber work and be an important determinant of the preferred gait mode (i.e., walk or run) at a

Kotaro Sasaki; Richard R. Neptune

2006-01-01

138

SOLAR ENERGY POTENTIAL IN JORDAN  

Microsoft Academic Search

This study is aimed to constitute a database for the researchers interested in utilizing solar power in Jordan. It presents the investigation for seven sites distributed on all territory of the country. Based on long-term measured solar irradiation levels, provided by the National Energy Research Center, solar insolation profiles as well as solar irradiance characteristics are estimated. The obtained results

Yaser Anagreh; Ahmad Bataineh; Muhammad Al-Odat

139

On the Chemical Potential of Dark Energy  

E-print Network

It is widely assumed that the observed universe is accelerating due to the existence of a new fluid component called dark energy. In this article, the thermodynamics consequences of a nonzero chemical potential on the dark energy component is discussed with special emphasis to the phantom fluid case. It is found that if the dark energy fluid is endowed with a negative chemical potential, the phantom field hypothesis becomes thermodynamically consistent with no need of negative temperatures as recently assumed in the literature.

S. H. Pereira

2008-06-23

140

Nudged-elastic band used to find reaction coordinates based on the free energy  

NASA Astrophysics Data System (ADS)

Transition paths characterize chemical reaction mechanisms. In this paper, we present a new method to find mean reaction paths based on the free energy. A nudged elastic band (NEB) is optimized using gradients and Hessians of the free energy, which are obtained from umbrella integration. The transition state can be refined by a Newton-Raphson search starting from the highest point of the NEB path. All optimizations are done using Cartesian coordinates. Independent molecular dynamics (MD) runs are performed at each image used to discretize the path. This makes the method intrinsically parallel. In contrast to other free energy methods, the algorithm does not become more expensive when including more degrees of freedom in the active space. The method is applied to the alanine-dipeptide as a test case and compared to pathways that have been derived from metadynamics and forward flux sampling.

Bohner, Matthias U.; Zeman, Johannes; Smiatek, Jens; Arnold, Axel; Kästner, Johannes

2014-02-01

141

Nudged-elastic band used to find reaction coordinates based on the free energy.  

PubMed

Transition paths characterize chemical reaction mechanisms. In this paper, we present a new method to find mean reaction paths based on the free energy. A nudged elastic band (NEB) is optimized using gradients and Hessians of the free energy, which are obtained from umbrella integration. The transition state can be refined by a Newton-Raphson search starting from the highest point of the NEB path. All optimizations are done using Cartesian coordinates. Independent molecular dynamics (MD) runs are performed at each image used to discretize the path. This makes the method intrinsically parallel. In contrast to other free energy methods, the algorithm does not become more expensive when including more degrees of freedom in the active space. The method is applied to the alanine-dipeptide as a test case and compared to pathways that have been derived from metadynamics and forward flux sampling. PMID:24559340

Bohner, Matthias U; Zeman, Johannes; Smiatek, Jens; Arnold, Axel; Kästner, Johannes

2014-02-21

142

Nudged-elastic band method with two climbing images: finding transition states in complex energy landscapes  

E-print Network

The nudged-elastic band (NEB) method is modified with concomitant two climbing images (C2-NEB) to find a transition state (TS) in complex energy landscapes, such as those with serpentine minimal energy path (MEP). If a single climbing image (C1-NEB) successfully finds the TS, C2-NEB finds it with higher stability and accuracy. However, C2-NEB is suitable for more complex cases, where C1-NEB misses the TS because the MEP and NEB directions near the saddle point are different. Generally, C2-NEB not only finds the TS but guarantees that the climbing images approach it from the opposite sides along the MEP, and it estimates accuracy from the three images: the highest-energy one and its climbing neighbors. C2-NEB is suitable for fixed-cell NEB and the generalized solid-state NEB (SS-NEB).

Zarkevich, Nikolai A

2014-01-01

143

Unlocking potential for energy reduction.  

PubMed

In the latest of our series of articles designed to provide healthcare engineers with sound technical guidance on equipment or technology-related topics, John O'Leary, key account manager at Trend Controls (who in April's HEJ discussed the benefits of natural ventilation in healthcare settings), explains the functions of a building energy management system (BEMS), and the vital that role such equipment can play in helping healthcare estates teams reduce carbon emissions and save money, as well as ensuring the most comfortable environment for patients, staff, and visitors. PMID:23763085

O'Leary, John

2013-05-01

144

Experimental study of {sup 6}He+{sup 9}Be elastic scattering at low energies  

SciTech Connect

New data for the {sup 6}He+{sup 9}Be reaction at E{sub lab}=16.2 and 21.3 MeV have been taken and analyzed. The effect of the collective couplings to the excited states of the target has been studied by means of coupled-channels calculations, using a double-folding potential for the bare interaction between the colliding nuclei, supplemented with a phenomenological imaginary part of Woods-Saxon type. In addition, three- and four-body continuum-discretized coupled-channels calculations have been performed to investigate the effect of the projectile breakup on the elastic scattering. Both effects, the coupling to target and projectile excited states, are found to affect significantly the elastic scattering. The trivial local polarization potential extracted from the continuum-discretized coupled-channels calculations indicates that continuum couplings produce a repulsive real part and a long-range imaginary part in the projectile-target interaction.

Pires, K. C. C.; Lichtenthaeler, R.; Lepine-Szily, A.; Guimaraes, V.; Faria, P. N. de; Barioni, A.; Mendes Junior, D. R.; Morcelle, V.; Pampa Condori, R.; Morais, M. C.; Zamora, J. C.; Crema, E.; Moro, A. M.; Rodriguez-Gallardo, M.; Assuncao, M.; Shorto, J. M. B.; Mukherjee, S. [Departamento de Fisica Nuclear, Universidade de Sao Paulo, C.P. 66318, 05389-970, Sao Paulo (Brazil); Departamento de FAMN, Facultad de Fisica, Universidad de Sevilla, Apdo. 1065, E-41080 Sevilla (Spain); Instituto de Estructura de la Materia, CSIC, Serrano 123, E-28006 Madrid, Spain Departamento de FAMN, Facultad de Fisica, Universidad de Sevilla, Apdo. 1065, E-41080 Sevilla (Spain); Departamento de Ciencias Exatas e da Terra, Universidade Federal de Sao Paulo, Campus Diadema, Sao Paulo (Brazil); Instituto de Pesquisas Energeticas e Nucleares (IPEN-CNEN), Comissao Nacional de Energia Nuclear, Sao Paulo (Brazil); Physics Department, Faculty of Science, M.S. University of Baroda, Vadodara (India)

2011-06-15

145

Energy potential of modern landfills  

SciTech Connect

Methane produced by refuse decomposition in a sanitary landfill can be recovered for commercial use. Landfill methane is currently under-utilized, with commercial recovery at only a small percentage of US landfills. New federal regulations mandating control of landfill gas migration and atmospheric emissions are providing impetus to methane recovery schemes as a means of recovering costs for increased environmental control. The benefits of landfill methane recovery include utilization of an inexpensive renewable energy resource, removal of explosive gas mixtures from the subsurface, and mitigation of observed historic increases in atmospheric methane. Increased commercial interest in landfill methane recovery is dependent on the final form of Clean Air Act amendments pertaining to gaseous emissions from landfills; market shifts in natural gas prices; financial incentives for development of renewable energy resources; and support for applied research and development to develop techniques for increased control of the gas generation process in situ. This paper will discuss the controls on methane generation in landfills. In addition, it will address how landfill regulations affect landfill design and site management practices which, in turn, influence decomposition rates. Finally, future trends in landfilling, and their relationship to gas production, will be examined. 19 refs., 2 figs., 3 tabs.

Bogner, J.E.

1990-01-01

146

Zero-point energies in potential-energy surfaces  

Microsoft Academic Search

The definition of potential-energy surfaces (PES) and mass parameters in microscopic collective theories implies a folding over a collective wave packet. Thus the PES contains the zero-point energy (ZPE) of the packet, which should be extracted before using the collective potential any further. This paper concentrates on the kinetic energy part of the ZPE, its influence on the quantization procedure

P. G. Reinhard

1975-01-01

147

The synergy between protein positioning and DNA elasticity: energy minimization of protein-decorated DNA minicircles  

E-print Network

The binding of proteins onto DNA contributes to the shaping and packaging of genome as well as to the expression of specific genetic messages. With a view to understanding the interplay between the presence of proteins and the deformation of DNA involved in such processes, we developed a new method to minimize the elastic energy of DNA fragments at the mesoscale level. Our method makes it possible to obtain the optimal pathways of protein-decorated DNA molecules for which the terminal base pairs are spatially constrained. We focus in this work on the deformations induced by selected architectural proteins on circular DNA. We report the energy landscapes of DNA minicircles subjected to different levels of torsional stress and containing one or two proteins as functions of the chain length and spacing between the proteins. Our results reveal cooperation between the elasticity of the double helix and the structural distortions of DNA induced by bound proteins. We find that the imposed mechanical stress influence...

Clauvelin, Nicolas

2014-01-01

148

A curved detection-slit to improve ERD (Elastic Recoil Detection) energy/depth resolution  

SciTech Connect

Recoil atoms detected in Elastic Recoil Detection (ERD) experiments emerge from an initial collision area along cones of constant energy due to the cylindrical symmetry of the elastic scattering cross section. The constant energy cones therefore intercept planar slit plates placed before the detectors in conic sections. For ease of fabrication slits are typically configured as long narrow rectangles, and as a result energy resolution is adversely affected. It has been shown that the kinematic broadening caused by using rectangular slits is minimized when L = 2 (W z tan/Theta//sub recoil/)/sup 1/2/ where W is the slit width, L is the slit length, z is the slit-target distance and /Theta//sub recoil/ is the lab-frame recoil angle. The improved energy resolution which results when rectangular slits are replaced by appropriate curved slits is examined here. Formulas are given for the conic sections associated with the curved slits as a function of experimental geometry. When slit dimensions are small compared with the full extent of the conic section slit geometry can be accurately approximated as the arc of a circle with radius R/sub c/ = z tan/Theta//sub recoil/. Energy loss effects on the resolution are also accounted for in our treatment. The use of curved slits with L = 4 (W z tan/Theta//sub recoil/)/sup 1/2/ is shown to improve kinematic broadening by /approximately/50% as compared to optimized rectangular slits of the same area. 2 refs., 5 figs.

Brice, D.K.; Doyle, B.L.

1989-01-01

149

Energy saving potential of various roof technologies  

E-print Network

Unconventional roof technologies such as cool roofs and green roofs have been shown to reduce building heating and cooling load. Although previous studies suggest potential for energy savings through such technologies, ...

Ray, Stephen D. (Stephen Douglas)

2010-01-01

150

Elastic energy storage and radial forces in the myofilament lattice depend on sarcomere length.  

PubMed

We most often consider muscle as a motor generating force in the direction of shortening, but less often consider its roles as a spring or a brake. Here we develop a fully three-dimensional spatially explicit model of muscle to isolate the locations of forces and energies that are difficult to separate experimentally. We show the strain energy in the thick and thin filaments is less than one third the strain energy in attached cross-bridges. This result suggests the cross-bridges act as springs, storing energy within muscle in addition to generating the force which powers muscle. Comparing model estimates of energy consumed to elastic energy stored, we show that the ratio of these two properties changes with sarcomere length. The model predicts storage of a greater fraction of energy at short sarcomere lengths, suggesting a mechanism by which muscle function shifts as force production declines, from motor to spring. Additionally, we investigate the force that muscle produces in the radial or transverse direction, orthogonal to the direction of shortening. We confirm prior experimental estimates that place radial forces on the same order of magnitude as axial forces, although we find that radial forces and axial forces vary differently with changes in sarcomere length. PMID:23166482

Williams, C David; Regnier, Michael; Daniel, Thomas L

2012-01-01

151

Industrial Energy Conservation Potentials in North Carolina  

E-print Network

~ The technique involves removing up to half;of the existing tubes and ballasts, and installing the reflectors over the remaining lamps. . , The follOWing equation should be used to estimate the potential energy savings E, when efficient lighting management...~ The technique involves removing up to half;of the existing tubes and ballasts, and installing the reflectors over the remaining lamps. . , The follOWing equation should be used to estimate the potential energy savings E, when efficient lighting management...

Barakat, M. G.; Singh, H.; Mallik, A. K.

152

Low-energy elastic electron scattering from isobutanol and related alkyl amines  

NASA Astrophysics Data System (ADS)

Normalized experimental differential and integral cross sections for vibrationally elastic scattering of low-energy electrons from isobutanol (C4H9OH ) are presented. The differential cross sections are measured at incident energies from 1 to 100 eV and scattering angles from 5? to 130?. These cross sections are compared to earlier experimental and theoretical results for isobutanol and n-butanol, as well as to results for smaller alcohols and for alkanes. Further comparisons are made with calculated cross sections for isobutylamine (C4H9NH2) and for smaller amines, including ethylamine (C2H5NH2), dimethylamine (CH3NHCH3), the two C3H7NH2 isomers n-propylamine and isopropylamine, and ethylene diamine (NH2C2H4NH2). The calculated cross sections are obtained using the Schwinger multichannel method. The comparisons illuminate the role of molecular structure in determining the angular distribution of resonantly scattered electrons.

Fedus, Kamil; Navarro, C.; Hargreaves, L. R.; Khakoo, M. A.; Silva, F. M.; Bettega, M. H. F.; Winstead, C.; McKoy, V.

2014-09-01

153

Sub-wavelength energy trapping of elastic waves in a metamaterial.  

PubMed

Deep sub-wavelength focusing has been demonstrated for locally resonant metamaterials using electromagnetic and acoustic waves. The elastic equivalents of such objects are made of sub-wavelength resonating beams fixed to a two-dimensional plate, as presented here. Independent of a random or regular arrangement of the resonators, the metamaterial shows large bandgaps that are independent of the incident wave direction. Numerical simulations demonstrate that the insertion of a defect in the layout, as a shorter resonator, creates strong amplification of the wave-field on the defect. This energy trapping, which is localized on a spatial scale that is much smaller than the wavelength in the two-dimensional plate, leads to a >1 factor in terms of the local density of energy. PMID:25096146

Colombi, Andrea; Roux, Philippe; Rupin, Matthieu

2014-08-01

154

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

155

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

156

Investigation of contact electrification based broadband energy harvesting mechanism using elastic PDMS microstructures  

NASA Astrophysics Data System (ADS)

Triboelectric energy harvesting has recently garnered a lot of interest because of its easy fabrication and high power output. Contact electrification depends on the chemical properties of contacting materials. Another important factor in contact electrification mechanism is surfaces’ elastic and topographical characteristics. One of the biggest limitations of resonant mechanism based devices is their narrow operating bandwidth. This paper presents a broadband mechanism which utilizes stiffness induced in the cantilever motion due to contact between two triboelectric surfaces. We have conducted experiments using polydimethylsiloxane (PDMS) micropad patterns to study the effect of micropad array configuration on the performance of triboelectric energy harvesting devices. The maximum power output measured from the device was observed to be 0.69??W at an acceleration of 1?g. Due to the non-linearity introduced by contact separation mechanism, the bandwidth of the triboelectric energy harvester was observed to be increased by 63% at an acceleration level of 1?g. A hybrid energy harvesting mechanism has also been demonstrated by compounding the triboelectric energy harvester with a piezoelectric bimorph.

Dhakar, Lokesh; Tay, F. E. H.; Lee, Chengkuo

2014-10-01

157

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

SciTech Connect

The diffractive features of angular distribution have been investigated by analyzing the experimental data for a set of elastic scattering processes of {sup 7}Li 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 [Physics Department, Faculty of Sciences, The Hashemite University, Zarqa (Jordan)

2013-12-16

158

Quantum potential energy as concealed motion  

E-print Network

It is known that the Schroedinger equation may be derived from a hydrodynamic model in which the Lagrangian position coordinates of a continuum of particles represent the quantum state. Using Routh\\s method of ignorable coordinates it is shown that the quantum potential energy of particle interaction that represents quantum effects in this model may be regarded as the kinetic energy of additional concealed freedoms. The method brings an alternative perspective to Planck\\s constant, which plays the role of a hidden variable, and to the canonical quantization procedure, since what is termed kinetic energy in quantum mechanics may be regarded literally as energy due to motion.

Peter Holland

2014-10-01

159

Elastic energy and string configurations in the chiral gauge theory of biaxial uniaxial nematic phase transitions  

E-print Network

In nematic liquid crystals (NLCs), topological defects of a chiral origin play a role in phase transitions and lead to phase configurations of nontrivial topology, like those in neutron stars and helium in the A-phase. In the biaxial-uniaxial phase transition, the deformation of the orbit, as the order parameter degeneracy of the NLC, connects together an evolution of topological defects, the surface anchoring energy and elastic Frank modui. In this work we estimate the chiral gauge field presentation of the constrained Ladnau-de Gennes theory of the biaxial nematics, which have to explain their topologically dependent phase transformation, using the description of the transformation of disclinations in the biaxial nematic phase into the surface bojooms of a uniaxial NLC.

L. V. Elnikova

2014-10-09

160

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

NASA Astrophysics Data System (ADS)

Differential neutron elastic scattering cross sections for 12C , 40Ca , and 208Pb 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° to 23°. 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.; Haight, R. C.; Rapaport, J.; Finlay, R. W.; Bauge, E.; Delaroche, J. P.; Koning, A. J.

2004-11-01

161

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

162

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

163

How upgoing and downgoing energy fluxes contribute to the establishment of lamb waves in an immersed elastic  

E-print Network

How upgoing and downgoing energy fluxes contribute to the establishment of lamb waves-27 April 2012, Nantes, France 619 #12;Ultrasonic guided waves in an anisotropic elastic plate immersed (surface) waves are involved in the problem if the incidence angle is greater than the first critical angle

Boyer, Edmond

164

Precision Pion-Proton Elastic Differential Cross Sections at Energies Spanning the Delta Resonance  

E-print Network

A precision measurement of absolute pi+p and pi-p elastic differential cross sections at incident pion laboratory kinetic energies from T_pi= 141.15 to 267.3 MeV is described. Data were obtained detecting the scattered pion and recoil proton in coincidence at 12 laboratory pion angles from 55 to 155 degrees for pi+p, and six angles from 60 to 155 degrees for pi-p. Single arm measurements were also obtained for pi+p energies up to 218.1 MeV, with the scattered pi+ detected at six angles from 20 to 70 degrees. A flat-walled, super-cooled liquid hydrogen target as well as solid CH2 targets were used. The data are characterized by small uncertainties, ~1-2% statistical and ~1-1.5% normalization. The reliability of the cross section results was ensured by carrying out the measurements under a variety of experimental conditions to identify and quantify the sources of instrumental uncertainty. Our lowest and highest energy data are consistent with overlapping results from TRIUMF and LAMPF. In general, the Virginia Polytechnic Institute SM95 partial wave analysis solution describes our data well, but the older Karlsruhe-Helsinki PWA solution KH80 does not.

M. M. Pavan; J. T. Brack; F. Duncan; A. Feltham; G. Jones; J. Lange; K. J. Raywood; M. E. Sevior; R. Adams; D. F. Ottewell; G. R. Smith; B. Wells; R. L. Helmer; E. L. Mathie; R. Tacik; R. A. Ristinen; I. I. Strakovsky; H-M. Staudenmaier

2001-03-15

165

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

166

Potential reduction of DSN uplink energy cost  

NASA Technical Reports Server (NTRS)

DSN Earth stations typically transmit more power than that required to meet minimum specifications for uplink performance. Energy and cost savings that could result from matching the uplink power to the amount required for specified performance are studied. The Galileo mission was selected as a case study. Although substantial reduction in transmitted energy is possible, potential savings in source energy (oil or electricity) savings are much less. This is because of the rising inefficiency in power conversion and radio frequency power generation that accompanies reduced power output.

Dolinsky, S.; Degroot, N. F.

1982-01-01

167

The wind energy potential of western Greece  

Microsoft Academic Search

In this study wind data were used to determine the monthly and annual variations of the wind at 13 meterological stations in western Greece. An analysis of the available wind data for the Ionian Sea islands and the western coasts of Greece is carried out to ascertain its potential for wind energy development. The effect of the limited number of

B. D. Katsoulis; D. A. Metaxas

1992-01-01

168

Renewable Energy Potential for Brownfield Redevelopment Strategies  

E-print Network

to identify high-potential sites for renewable energy technologies and can help determine those technologies (see Figure 3). Thus, the decision to install a PV system depends on the power requirements to brownfields. Given economic and technological considerations, the most suitable at this time are growing

169

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

170

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

171

Do halo nuclei follow Rutherford elastic scattering at energies below the barrier? The case of 11Li.  

PubMed

The first measurement of the elastic scattering of the halo nucleus 11Li and its core 9Li on 208Pb at energies near the Coulomb barrier is presented. The 11Li+208Pb elastic scattering shows a strong reduction with respect to the Rutherford cross section, even at energies well below the barrier and down to very small scattering angles. This drastic change of the elastic differential cross section observed in 11Li+208Pb is the consequence of the halo structure of 11Li, as it is not observed in the elastic scattering of its core 9Li at the same energies. Four-body continuum-discretized coupled-channels calculations, based on a three-body model of the 11Li projectile, are found to explain the measured angular distributions and confirm that the observed reduction is mainly due to the strong Coulomb coupling to the dipole states in the low-lying continuum of 11Li. These calculations suggest the presence of a low-lying dipole resonance in 11Li close to the breakup threshold. PMID:23368554

Cubero, M; Fernández-García, J P; Rodríguez-Gallardo, M; Acosta, L; Alcorta, M; Alvarez, M A G; Borge, M J G; Buchmann, L; Diget, C A; Al Falou, H; Fulton, B R; Fynbo, H O U; Galaviz, D; Gómez-Camacho, J; Kanungo, R; Lay, J A; Madurga, M; Martel, I; Moro, A M; Mukha, I; Nilsson, T; Sánchez-Benítez, A M; Shotter, A; Tengblad, O; Walden, P

2012-12-28

172

Molecular spinless energies of the improved Tietz potential energy model  

NASA Astrophysics Data System (ADS)

We solve the Klein-Gordon equation with the improved Tietz empirical potential energy model. The bound state energy equation has been obtained by using the supersymmetric shape invariance approach. The relativistic vibrational transition frequencies for the state of Na2 molecule have been computed by using the improved Tietz potential model. The relativistic vibrational transition frequencies are in good agreement with the experimental RKR values.

Liu, Jian-Yi; Du, Jian-Fen; Jia, Chun-Sheng

2013-11-01

173

Elastic moduli, dislocation core energy, and melting of hard disks in two dimensions  

NASA Astrophysics Data System (ADS)

Elastic moduli and dislocation core energy of the triangular solid of hard disks of diameter ? are obtained in the limit of vanishing dislocation-antidislocation pair density, from Monte Carlo simulations that incorporate a constraint, namely that all moves altering the local connectivity away from that of the ideal triangular lattice are rejected. In this limit we show that the solid is stable against all other fluctuations at least up to densities as low as ??2=0.88. Our system does not show any phase transition so diverging correlation lengths leading to finite size effects and slow relaxations do not exist. The dislocation pair formation probability is estimated from the fraction of moves rejected due to the constraint which yields, in turn, the core energy Ec and the (bare) dislocation fugacity y. Using these quantities, we check the relative validity of first order and Kosterlitz-Thouless-Halperin-Nelson-Young (KTHNY) melting scenarios and obtain numerical estimates of the typical expected transition densities and pressures. We conclude that a KTHNY transition from the solid to a hexatic phase preempts the solid to liquid first order transition in this system albeit by a very small margin, easily masked by crossover effects in unconstrained ``brute- force'' simulations with a small number of particles.

Sengupta, Surajit; Nielaba, Peter; Binder, K.

2000-06-01

174

Three-phase plane composites of minimal elastic stress energy: High-porosity structures  

E-print Network

The paper establishes exact lower bound on the effective elastic energy of two-dimensional, three-material composite subjected to the homogeneous, anisotropic stress. It is assumed that the materials are mixed with given volume fractions and that one of the phases is degenerated to void, i.e. the effective composite is porous. Explicit formula for the energy bound is obtained using the translation method enhanced with additional inequality expressing certain property of stresses. Sufficient optimality conditions of the energy bound are used to set the requirements which have to be met by the stress fields in each phase of optimal effective material regardless of the complexity of its microstructural geometry. We show that these requirements are fulfilled in a special class of microgeometries, so-called laminates of a rank. Their optimality is elaborated in detail for structures with significant amount of void, also referred to as high-porosity structures. It is shown that geometrical parameters of optimal multi-rank, high-porosity laminates are different in various ranges of volume fractions and anisotropy level of external stress. Non-laminate, three-phase microstructures introduced by other authors and their optimality in high-porosity regions is also discussed by means of the sufficient conditions technique. Conjectures regarding low-porosity regions are presented, but full treatment of this issue is postponed to a separate publication. The corresponding "G-closure problem" of a three-phase isotropic composite is also addressed and exact bounds on effective isotropic properties are explicitly determined in these regions where the stress energy bound is optimal.

Andrej Cherkaev; Grzegorz Dzierzanowski

2013-02-12

175

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

176

Exploring for the Sources of Internal Elastic Deformations Using Potential Fields and Their Poisson Wavelets; Possible Applications to InSAR Observations  

NASA Astrophysics Data System (ADS)

From a restricted solution of the Cauchy-Navier equations of quasi-static infinitesimal elasticity theory [Green and Zerna, 1968, section 5.7] for an isotropic, linear elastic half-space with a shear-traction free ground surface, we find a scalar function ? that is present underground wherever internal deformations are generated, and absent elsewhere. The "deformation source density" ? is related to the magnitude of changes in body forces (e.g. frictional traction changes across a creeping fault surface) and is the source of a potential field, like mass density for vertical gravitational acceleration, or the divergence of magnetization for total magnetic intensity. Surveys of surface displacements (e.g. InSAR range changes) may be turned into the potential field at the surface of the half-space via standard 2D Fourier domain techniques. From this potential, a harmonic field may be constructed above the measurement plane. All of potential field theory and practice [e.g., Blakely, 1996] is applicable to analyzing such data for information about the underground distribution and strength of ?. In particular the potential field Poisson wavelet system of Hornby, Boschetti,and Horowitz [1999] —-- being generated by the Green's function for harmonic potentials —-- is ideally suited for such analysis, with all of the multiscale edge ("worm") discontinuity analysis, and the dipole source inverse wavelet transform ideas being directly applicable. We regard this as a gentle approach "halfway to inversion" which allows for a visual interpretation of maps of surficial displacement measurements to occur before a full inversion is performed. References: Blakely, R. J. (1996), Potential Theory in Gravity and Magnetic Applications, Cambridge University Press, Cambridge. Green, A. E., and W. Zerna (1968), Theoretical Elasticity, 2nd ed., Oxford University Press, Clarendon. Hornby, P., F. Boschetti, and F. G. Horowitz (1999), Analysis of Potential Field Data in the Wavelet Domain, Geophysical Journal International, 137 (1), 175 -196, doi:10.1046/j.1365-246x.1999.00788.x.

Horowitz, F. G.; Hornby, P.

2006-12-01

177

Sparse representation for a potential energy surface  

NASA Astrophysics Data System (ADS)

We propose a simple scheme to estimate the potential energy surface (PES) for which the accuracy can be easily controlled and improved. It is based on model selection within the framework of linear regression using the least absolute shrinkage and selection operator (LASSO) technique. Basis functions are selected from a systematic large set of candidate functions. The sparsity of the PES significantly reduces the computational cost of evaluating the energy and force in molecular dynamics simulations without losing accuracy. The usefulness of the scheme for describing the elemental metals Na and Mg is clearly demonstrated.

Seko, Atsuto; Takahashi, Akira; Tanaka, Isao

2014-07-01

178

A study of elastic and inelastic collisions of 58Ni+90,94Zr at two near-barrier energies  

NASA Astrophysics Data System (ADS)

Pure elastic scattering cross sections for the systems 58Ni+90,94Zr have been measured at energies of 247.5 and 232.5 MeV, making use of the ENMA spectrograph which is particularly suited for heavy-ion reactions. Also the differential cross sections for the excitation of the first 2+ inelastic state of 58Ni in the 58Ni+90Zr combination were extracted. Simple coupled channel calculations successfully reproduce the data at 247.5 MeV while some improvement is needed for the lower energy. Calculations with the code CC-FUS, based on the real optical model parameters extracted from the elastic scattering measurements, are compared with the previously measured fusion cross sections at energies near and below the Coulomb barrier.

Corradi, L.; Napoli, D. R.; Stefanini, A. M.; Signorini, C.; Sugiyama, Y.; Ikezoe, H.; Tomita, Y.; Ideno, K.; Kim, H. J.; Nagashima, Y.; Masuda, T.; Fujiwara, H.; Pu, Ye Hu; Tagishi, Y.; Sugimitsu, T.; Qi, B.

1992-03-01

179

Renewable energy in India: Current status and future potentials  

Microsoft Academic Search

Renewable energy sources and technologies have potential to provide solutions to the long-standing energy problems being faced by the developing countries. The renewable energy sources like wind energy, solar energy, geothermal energy, ocean energy, biomass energy and fuel cell technology can be used to overcome energy shortage in India. To meet the energy requirement for such a fast growing economy,

Ashwani Kumar; Kapil Kumar; Naresh Kaushik; Satyawati Sharma; Saroj Mishra

2010-01-01

180

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

181

Elastic energy storage in the shoulder and the evolution of high-speed throwing in Homo  

PubMed Central

Although some primates, including chimpanzees, throw objects occasionally1,2, only humans regularly throw projectiles with high speed and great accuracy. Darwin noted that humans’ unique throwing abilities, made possible when bipedalism emancipated the arms, enabled foragers to effectively hunt using projectiles3. However, there has been little consideration of the evolution of throwing in the years since Darwin made his observations, in part because of a lack of evidence on when, how, and why hominins evolved the ability to generate high-speed throws4-8. Here, we show using experimental studies of throwers that human throwing capabilities largely result from several derived anatomical features that enable elastic energy storage and release at the shoulder. These features first appear together approximately two million years ago in the species Homo erectus. Given archaeological evidence that suggests hunting activity intensified around this time9, we conclude that selection for throwing in order to hunt likely played an important role in the evolution of the human genus. PMID:23803849

Roach, Neil T.; Venkadesan, Madhusudhan; Rainbow, Michael J.; Lieberman, Daniel E.

2013-01-01

182

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

183

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

NASA Astrophysics Data System (ADS)

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.

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.

2014-07-01

184

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

185

Theoretical studies of potential energy surfaces  

SciTech Connect

The goal of this program is to calculate accurate potential energy surfaces (PES) for both reactive and nonreactive systems. To do this the electronic Schrodinger equation must be solved. Our approach to this problem starts with multiconfiguration self-consistent field (MCSCF) reference wavefunctions. These reference wavefunctions are designed to be sufficiently flexible to accurately describe changes in electronic structure over a broad range of geometries. Electron correlation effects are included via multireference, singles and doubles configuration interaction (MRSDCI) calculations. With this approach, the authors are able to provide useful predictions of the energetics for a broad range of systems.

Harding, L.B. [Argonne National Laboratory, IL (United States)

1993-12-01

186

The wind energy potential of western Greece  

SciTech Connect

In this study wind data were used to determine the monthly and annual variations of the wind at 13 meterological stations in western Greece. An analysis of the available wind data for the Ionian Sea islands and the western coasts of Greece is carried out to ascertain its potential for wind energy development. The effect of the limited number of daily observations available on the accuracy of the mean wind speed and annual wind energy estimates is ascertained. The wind speed and direction distributions are represented with Weibull functions. Besides, a mass-consistent numerical mesoscale model was used to give an overview of the wind prospecting and siting problem, and an example of its use for Corfu (Kerkira), an island in the Ionian Sea, is given. The comparison of the accuracy of the stimulation results versus measured wind at an available site is quite encouraging even though it cannot be conclusive since only one station is available.

Katsoulis, B.D.; Metaxas, D.A. (Univ. of Ioannina (Greece))

1992-12-01

187

The energy release rate of a pressurized crack in soft elastic materials: effects of surface tension and large deformation.  

PubMed

In this paper we present a theoretical study on how surface tension affects fracture of soft solids. In classical fracture theory, the resistance to fracture is partly attributed to the energy required to create new surfaces. Thus, the energy released to the crack tip must overcome the surface energy in order to propagate a crack. In soft materials, however, surface tension can cause significant deformation and can reduce the energy release rate for crack propagation by resisting the stretch of crack surfaces. We quantify this effect by studying the inflation of a penny-shaped crack in an infinite elastic body with applied pressure. To avoid numerical difficulty caused by singular fields near the crack tip, we derived an expression for the energy release rate which depends on the applied pressure, the surface tension, the inflated crack volume and the deformed crack area. This expression is evaluated using a newly developed finite element method with surface tension elements. Our calculation shows that, when the elasto-capillary number ? ? ?/Ea is sufficiently large, where ? is the isotropic surface tension, E is the small strain Young's modulus and a is the initial crack radius, both the energy release rate and the crack opening displacement of an incompressible neo-Hookean solid are significantly reduced by surface tension. For a sufficiently high elasto-capillary number, the energy release rate can be negative for applied pressure less than a critical amount, suggesting that surface tension can cause crack healing in soft elastic materials. PMID:25140489

Liu, Tianshu; Long, Rong; Hui, Chung-Yuen

2014-10-21

188

Strong pickup-coupling effect on p+{sup 10}Be and {sup 11}Be elastic scattering around 40A MeV incident energy  

SciTech Connect

To explore the nature of the coupling effects on p+{sup 10}Be and p+{sup 11}Be elastic scattering at incident energies of 39.1A and at 38.4A MeV, respectively, coupled reaction channels (CRC) calculations were performed for the {sup 10}Be(p,d){sup 9}Be and {sup 11}Be(p,d){sup 10}Be* pickup to the ground state of {sup 9}Be and the 5.960 MeV 1{sup -} and 6.263 MeV 2{sup -} doublet of excited states in {sup 10}Be at the corresponding incident energies. We show that within the CRC framework, the coupling effect on the elastic scattering is significant in both cases and produces effective absorption in the entrance channel. This suggests that the use of a fitted p+{sup 10}Be optical model potential may lead to too much absorption in the core plus proton interaction in extended coupled discretized continuum channels type of calculations for the p+{sup 11}Be system and that coupling to the {sup 11}Be(p,d){sup 10}Be* pickup should be explicitly included in such studies.

Keeley, N.; Lapoux, V. [CEA/DSM/DAPNIA/SPhN Saclay, F-91191 Gif-sur-Yvette Cedex (France)

2008-01-15

189

Unique potentials for the elastic scattering of 350 MeV 7Li from 12C and 28Si  

Microsoft Academic Search

Differential cross sections for the elastic scattering of 350 MeV 7Li from 12C and 28Si have been measured. The characteristics of the angular distributions are very similar to those of 318 MeV 6Li scattering from the same targets, with diffractive oscillations at the forward angles and smooth exponential falloff, attributed to the dominance of far-side scattering, at the larger angles.

A. Nadasen; J. Brusoe; J. Farhat; T. Stevens; J. Williams; L. Nieman; J. S. Winfield; R. E. Warner; F. D. Becchetti; J. W. Jänecke; T. Annakkage; J. Bajema; D. Roberts; H. S. Govinden

1995-01-01

190

Energy potential of leafy spurge (Euphorbia esula)  

SciTech Connect

Leafy spurge (Euphorbia esula) is a noxious, perennial weed that infests pastures, range land and waste areas in the northern Great Plains. The objective of this study was to determine the productive potential of this species when grown under optimum agronomic conditions. Plants were fertilized and irrigated. Oil, hydrocarbon, total protein, and dry-weight production were measured on 3 harvest dates. Calorimetric analyses were performed to determine the potential of leafy spurge as a fuel crop. The hydrocarbon content of 12 strains of leafy spurge was determined to measure genetic variability for this trait. The addition of fertilizer doubled dry-weight production but did not affect percent oil or hydrocarbon content. Oil and hydrocarbon production averaged 6.8 and 0.6% on a plant dry-weight basis. Maximum production of plant biomass, protein, and hydrocarbon was obtained from a mid-July harvest. Oil content increased later in the growing season. The total protein content of leafy spurge averaged 12%. Whole-plant biomass had a caloric value of 4407 cal/g while the oils contained 10,019 cal/g. Leafy spurge hay can produce 4 times more energy per year than wheat straw; therefore, the immediate potential of leafy spurge whole-plant biomass as a locally grown fuel crop for home-heating purposes is suggested.

Maxwell, B.D.; Wiatr, S.M.; Fay, P.K.

1985-01-01

191

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

192

Absolute differential cross sections for elastic and inelastic electron scattering from benzene with 1 kev impact energy  

NASA Astrophysics Data System (ADS)

The absolute generalized oscillator strength and absolute inelastic differential cross section have been determined, as a function of the momentum transfer, for the 1E1u + 1B1u larr 1Ag transition in the benzene molecule. A previously described electron energy-loss spectrometer, featuring a Wien-filter velocity analyser, has been used. Employing 1000 eV incident electron energy and 1.0 eV energy resolution, absolute oscillator strength distribution as a function of electron energy loss was obtained in the 2-8° scattering angle range. The absolute elastic differential cross section was also determined spanning an angular range of 2°-14°. The photoabsorption spectrum converted from the electron energy-loss spectrum was compared with the interstellar extinction curve where we confirm the proportionality between the cross section and extinction.

Boechat-Roberty, H. M.; Rocco, M. L. M.; Lucas, C. A.; de Souza, G. G. B.

2004-04-01

193

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

194

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

195

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

196

Energy conservation potential in Taiwanese textile industry  

Microsoft Academic Search

Since Taiwan lacks sufficient self-produced energy, increasing energy efficiency and energy savings are essential aspects of Taiwan’s energy policy. This work summarizes the energy savings implemented by 303 firms in Taiwan’s textile industry from the on-line Energy Declaration System in 2008. It was found that the total implemented energy savings amounted to 46,074ton of oil equivalent (TOE). The energy saving

Gui-Bing Hong; Te-Li Su; Jenq-Daw Lee; Tsung-Chi Hsu; Hua-Wei Chen

2010-01-01

197

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

198

Design guidance for elastic followup  

SciTech Connect

The basic mechanism of elastic followup is discussed in relation to piping design. It is shown how mechanistic insight gained from solutions for a two-bar problem can be used to identify dominant design parameters and to determine appropriate modifications where elastic followup is a potential problem. It is generally recognized that quantitative criteria are needed for elastic followup in the creep range where badly unbalanced lines can pose potential problems. Approaches for criteria development are discussed.

Naugle, F.V.

1983-01-01

199

ASSESSMENT OF ENERGY RECOVERY POTENTIAL OF INDUSTRIAL COMBUSTION EQUIPMENT  

EPA Science Inventory

An assessment was conducted to evaluate the waste heat content and energy recovery potential of flue gases from 30 industrial combustion devices. Pollution controls on nine of the devices were evaluated to estimate energy requirements and particulate reduction; energy requirement...

200

Energy Consumption and Conservation Potential at a Georgia Textile Plant  

E-print Network

is air-conditioned, the plant is an intensive user of electricity, fossil fuel, and water. Following completion of the energy analysis, recommendations to conserve energy and water resources were developed. Potential energy savings of approximately thirty...

Gurta, M. E.; Brown, M. L.

201

Monte Carlo simulation and parameterized treatment on the effect of nuclear elastic scattering in high-energy proton radiography  

E-print Network

A version of Geant4 has been developed to treat high-energy proton radiography. This article presents the results of calculations simulating the effects of nuclear elastic scattering for various test step wedges. Comparisons with experimental data are also presented. The traditional expressions of the transmission should be correct if the angle distribution of the scattering is Gaussian multiple Coulomb scattering. The mean free path which depends on the collimator angle and the radiation length are treated as empirical parameters, according to transmission as a function of thickness obtained by simulations. The results benefit for reconstructing density that depends on the transmission expressions.

Haibo, Xu

2014-01-01

202

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. Ramachandraa

203

Ab initio potential energy surfaces and nonadiabatic collision dynamics in H++O2 system  

NASA Astrophysics Data System (ADS)

The adiabatic potential energy surfaces for the lowest five electronic states of 3A'' symmetry for the H++O2 collision system have been obtained at the multireference configuration interaction level of accuracy using Dunning's correlation consistent polarized valence triple zeta basis set. The radial nonadiabatic coupling terms and the mixing angle between the lowest two electronic states (1 3A'' and 2 3A''), which adiabatically correlate in the asymptotic limit to H(2S)+O2+(X 2?g) and H++O2(X 3?g-), respectively, have been computed using ab initio procedures at the same level of accuracy to yield the corresponding quasidiabatic potential energy matrix. The computed strengths of the vibrational coupling matrix elements reflect the trend observed for inelastic vibrational excitations of O2 in the experiments at collision energy of 9.5 eV. The quantum dynamics has been preformed on the newly obtained coupled quasidiabatic potential energy surfaces under the vibrational close-coupling rotational infinite-order sudden framework at the experimental collision energy of 9.5 eV. The present theoretical results for vibrational elastic/inelastic excitations of O2 are in overall good agreement with the available experimental data obtained from the proton energy-loss spectra in molecular beam experiments [F. A. Gianturco et al., J. Phys. B 14, 667 (1981)]. The results for the complementary charge transfer processes are also presented at this collision energy.

Amaran, Saieswari; Kumar, Sanjay

2008-04-01

204

Response to 'Comment on 'Elastic incoherent neutron scattering operating by varying instrumental energy resolution: Principle, simulations, and experiments of the resolution elastic neutron scattering (RENS)'' [Rev. Sci. Instrum. 83, 107101 (2012)  

SciTech Connect

Recently [S. Magazu et al., Rev. Sci. Instrum. 82, 105115 (2011)] we have proposed a new method for characterizing, by neutron scattering, the dynamical properties of complex material systems, such as, the ones of interest in the biophysical field. This approach called Resolution Elastic Neutron Scattering, in short RENS, is based on the detection of the elastically scattered neutron intensity as a function of the instrumental energy resolution. By experimental, theoretical, and numerical findings, we have pointed out that an inflection point occurs in the elastic intensity when the system relaxation time approaches the instrumental energy resolution time. This approach, differently from quasi-elastic neutron scattering (QENS), gives the chance to evaluate the system relaxation times without using pre-defined models that can be wrong and/or misleading. Here, we reply to a Comment on the above-mentioned main paper in which Wuttke proposes a different approach to evaluate the above-mentioned inflection point; on this regard, it should be noticed that the existence of the inflection point, which is the main topic of our work, is not questioned and that the approach proposed by Wuttke in the Comment, although valid for a class of dynamical processes, is not applicable when different and distinct processes occur simultaneously at different time scale.

Magazu, Salvatore; Migliardo, Federica; Benedetto, Antonio [Dipartimento di Fisica, Universita di Messina, C.da Papardo n Degree-Sign 31, P.O. Box 55, Vill. S. Agata 98166 Messina (Italy)

2012-10-15

205

Static task of von Mises planar truss analyzed using the potential energy  

NASA Astrophysics Data System (ADS)

A Von Mises planar truss subjected to vertical static load at its top joint is studied. The mathematical concept of large displacement elastic analysis of the von Mises truss targeted for computers is described. The model geometry is described using finite mass points. Formulae for the evaluation of displacements of mass points and rotation of segments were derived with the help of geometrical and physical conditions. Formulae for the determination of potential energy of the system are listed. Deformation of the structure is evaluated by seeking the minimal potential energy. The step-by-step increment method combined with Newton-Raphson method is used. The mathematical solution described in the article enables the modelling of Mises truss using a finite amount of segments. The described solution is suitable for load-deflection curve computation of a limit load model. The equilibrium stability problem of von Mises truss is discussed in connection with the random effects of imperfections.

Kalina, Martin

2013-10-01

206

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

207

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

208

Elastic Properties of Random Percolating Systems  

Microsoft Academic Search

We study the macroscopic elastic moduli of an elastic percolating network in the critical region. A microscopic elastic Hamiltonian is used, which contains a bending energy term. We find that the rigidity threshold of this system is identical to the percolation threshold pc. By considering the elastic properties of elements of the infinite percolation cluster we calculate the critical exponent

Yacov Kantor; Itzhak Webman

1984-01-01

209

Elastic and inelastic scattering of {sup 16}O+{sup 64}Zn at near-barrier energies  

SciTech Connect

Elastic and inelastic scattering angular distributions were measured for the {sup 16}O+{sup 64}Zn reaction at bombarding energies close to the Coulomb barrier. The experimental data were analyzed within the optical model and coupled-channel model. An extended dispersion relation of integral quantities using a Gaussian weight was applied, instead of the normal relationship. Within this frame, the optical model parameters obtained from the data are in agreement with the dispersion relation and show the threshold anomaly at energies close to the Coulomb barrier. Analysis of the inelastic scattering angular distributions leads to some indications that an inelastic threshold anomaly is beginning to develop at energies lower than the ones for which our data were taken. {copyright} {ital 1996 The American Physical Society.}

Tenreiro, C.; Acquadro, J.C.; Freitas, P.A.; Liguori Neto, R. [Universidade de Sao Paulo, IFUSP Laboratorio Pelletron, C.P. 20516-01498-970, Sao Paulo (Brazil)] [Universidade de Sao Paulo, IFUSP Laboratorio Pelletron, C.P. 20516-01498-970, Sao Paulo (Brazil); Ramirez, G.; Cuevas, N. [Departamento de Fisica, Facultad de Ciencias, Universidad de Chile, Casilla 653, Santiago 1 (Chile)] [Departamento de Fisica, Facultad de Ciencias, Universidad de Chile, Casilla 653, Santiago 1 (Chile); Gomes, P.R.; Cabezas, R.; Anjos, R.M. [Departamento de Fisica, Universidade Federal Fluminense, Av. Gal. Milton Tavares de Souza s/n, Niteroi, R. J., 24210 (Brazil)] [Departamento de Fisica, Universidade Federal Fluminense, Av. Gal. Milton Tavares de Souza s/n, Niteroi, R. J., 24210 (Brazil); Copnell, J. [University of Manchester, Physics Department, Schuster Laboratories, Manchester M13 9PL (United Kingdom)] [University of Manchester, Physics Department, Schuster Laboratories, Manchester M13 9PL (United Kingdom)

1996-06-01

210

Biomass energy: the scale of the potential resource  

E-print Network

Biomass energy: the scale of the potential resource Christopher B. Field1 , J. Elliott Campbell1 Avenue, Livermore, CA 94550, USA Increased production of biomass for energy has the potential to offset resources and decrease food security. The net effect of biomass energy agriculture on climate could

211

Potential of solar energy for Texas  

Microsoft Academic Search

Evaluated is the rapidly growing solar energy program and it is determined which areas are appropriate for immediate development in Texas. Home heating and cooling via solar energy as well as integration of solar energy into electric and gas utilities are considered.

A. F. Hildebrandt

1974-01-01

212

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

213

Nonlinear elasticity, proteinquakes, and the energy landscapes of functional transitions in proteins  

PubMed Central

Large-scale motions of biomolecules involve linear elastic deformations along low-frequency normal modes, but for function nonlinearity is essential. In addition, unlike macroscopic machines, biological machines can locally break and then reassemble during function. We present a model for global structural transformations, such as allostery, that involve large-scale motion and possible partial unfolding, illustrating the method with the conformational transition of adenylate kinase. Structural deformation between open and closed states occurs via low-frequency modes on separate reactant and product surfaces, switching from one state to the other when energetically favorable. The switching model is the most straightforward anharmonic interpolation, which allows the barrier for a process to be estimated from a linear normal mode calculation, which by itself cannot be used for activated events. Local unfolding, or cracking, occurs in regions where the elastic stress becomes too high during the transition. Cracking leads to a counterintuitive catalytic effect of added denaturant on allosteric enzyme function. It also leads to unusual relationships between equilibrium constant and rate like those seen recently in single-molecule experiments of motor proteins. PMID:14566052

Miyashita, O.; Onuchic, J. N.; Wolynes, P. G.

2003-01-01

214

Microscopic self-energy calculations and dispersive optical-model potentials  

E-print Network

Nucleon self-energies for 40Ca, 48Ca, 60Ca isotopes are generated with the microscopic Faddeev-random-phase approximation (FRPA). These self-energies are compared with potentials from the dispersive optical model (DOM) that were obtained from fitting elastic-scattering and bound-state data for 40Ca and 48Ca. The \\textit{ab initio} FRPA is capable of explaining many features of the empirical DOM potentials including their nucleon asymmetry dependence. The comparison furthermore provides several suggestions to improve the functional form of the DOM potentials, including among others the exploration of parity and angular momentum dependence. The non-locality of the FRPA imaginary self-energy, illustrated by a substantial orbital angular momentum dependence, suggests that future DOM fits should consider this feature explicitly. The roles of the nucleon-nucleon tensor force and charge-exchange component in generating the asymmetry dependence of the FPRA self-energies are explored. The global features of the FRPA self-energies are not strongly dependent on the choice of realistic nucleon-nucleon interaction.

S. J. Waldecker; C. Barbieri; W. H. Dickhoff

2011-05-21

215

Evaluation of the Energy Saving Potential from Flue Gas Pressurization  

E-print Network

The potential for recovering energy from low pressure furnace flue products is limited when standard heat recovery equipment is utilized. Efficient energy recovery can be accomplished by providing a flue gas side pressure drop across a heat...

Stanton, E. H.

1980-01-01

216

Microscopic description of $^7$Li in the $^{7}\\text{Li}+^{12}\\text{C}$ and $^7\\text{Li}+^{28}\\text{Si}$ elastic scattering at high energies  

E-print Network

We employ a microscopic continuum-discretized coupled-channels reaction framework (MCDCC) to study the elastic angular distribution of the $^7$Li$=\\alpha+t$ nucleus colliding with $^{12}$C and $^{28}$Si targets at $E_{\\text{Lab}}$=350 MeV. In this framework, the $^7$Li projectile is described in a microscopic cluster model and impinges on non-composite targets. The diagonal and coupling potentials are constructed from nucleon-target interactions and $^7$Li 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 $^{7}$Li$+^{12}$C 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

2014-01-01

217

LBNL -50132 Assessment of Grid Distributed Energy Resource Potential  

E-print Network

LBNL -50132 Assessment of µGrid Distributed Energy Resource Potential Using DER-CAM and GIS Energy, Office of Power Technologies, Clean Energy Analysis Collaborative of the U.S. Department Berkeley National Laboratory is an equal opportunity employer. #12;Assessment of µGrid Distributed Energy

Kammen, Daniel M.

218

Quantifying National Energy Savings Potential of Lighting Controls in  

E-print Network

in reducing lighting energy use through more efficient lighting systems. The National Electrical ManufacturersQuantifying National Energy Savings Potential of Lighting Controls in Commercial Buildings Alison's Office of Energy Efficiency and Renewable Energy, Building Technologies Program under Contract No. DE

219

Ab initio study on stacking sequences, free energy, dynamical stability and potential energy surfaces of graphite structures  

NASA Astrophysics Data System (ADS)

Ab initio simulations have been performed to study the structure, energetics and stability of several plausible stacking sequences in graphite. These calculations suggest that in addition to the standard structures, graphite can also exist in AA-simple hexagonal, AB-orthorhombic and ABC-hexagonal type stacking. The free energy difference between these structures is very small (˜1 meV/atom), and hence all the structures can coexist from purely energetic considerations. Calculated x-ray diffraction patterns are similar to those of the standard structures for 2? ? 70°. Shear elastic constant C44 is negative in AA-simple hexagonal, AB-orthorhombic and ABC-hexagonal structures, suggesting that these structures are mechanically unstable. Phonon dispersions show that the frequencies of some modes along the ?-A direction in the Brillouin zone are imaginary in all of the new structures, implying that these structures are dynamically unstable. Incorporation of zero point vibrational energy via the quasi-harmonic approximation does not result in the restoration of dynamical stability. Potential energy surfaces for the unstable normal modes are seen to have the topography of a potential hill for all the new structures, confirming that all of the new structures are inherently unstable. The fact that the potential energy surface is not in the form of a double well implies that the structures are linearly as well as globally unstable.

Anees, P.; Valsakumar, M. C.; Chandra, Sharat; Panigrahi, B. K.

2014-04-01

220

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

221

Realizing the potential of nuclear energy. [Monograph  

Microsoft Academic Search

The future of nuclear power, just as the future of America, can be viewed with optimism. There is hope in America's record of overcoming obstacles, but growth is essential for that hope to be realized. Despite the downturn in energy demand made possible by conservation, we will need a 35% growth in total energy for new workers and production. Electricity

Walske

1982-01-01

222

Renewable Energy Resources Potential in Lao PDR  

Microsoft Academic Search

Renewable energy resources provide a large share of the total energy consumption of many developing countries. Evaluation of these resources has not been made in many countries and in many cases, data necessary to estimate the resource availability is also not easily available. However, for the profitable and sustained exploitation of these resources, a knowledge of their availability should be

KAYASITH SADETTANH

2004-01-01

223

Expedient Wind Energy Potential in Louisiana  

Microsoft Academic Search

Year after year, the world improves upon new ideas and forms of practical ways of applying green energy to humanity''s daily life. Some of these types include solar, nuclear, and natural gas energy, but wind power is growing in the ranks as far as popularity and usage. Countries such as China, the United States, and Germany have led the interest

Jasmin Honegger; Yucheng Liu

2012-01-01

224

Energy in America: Progress and Potential.  

ERIC Educational Resources Information Center

An overview of America's energy situation is presented with emphasis on recent progress, the risk of depending upon foreign oil, and policy choices. Section one reviews the energy problems of the 1970s, issues of the 1980s, concerns for the future, and choices that if made today could alleviate future problems. Section two examines past problems,…

American Petroleum Inst., Washington, DC.

225

Simulation of 12C+12C elastic scattering at high energy by using the Monte Carlo method  

NASA Astrophysics Data System (ADS)

The Monte Carlo method is used to simulate the 12C+12C reaction process. Taking into account the size of the incident 12C beam spot and the thickness of the 12C target, the distributions of scattered 12C on the MWPC and the CsI detectors at a detective distance have been simulated. In order to separate elastic scattering from the inelastic scattering with 4.4 MeV excited energy, we set several variables: the kinetic energy of incident 12C, the thickness of the 12C target, the ratio of the excited state, the wire spacing of the MWPC, the energy resolution of the CsI detector and the time resolution of the plastic scintillator. From the simulation results, the preliminary establishment of the experiment system can be determined to be that the beam size of the incident 12C is phi5 mm, the incident kinetic energy is 200-400 A MeV, the target thickness is 2 mm, the ratio of the excited state is 20%, the flight distance of scattered 12C is 3 m, the energy resolution of the CsI detectors is 1%, the time resolution of the plastic scintillator is 0.5%, and the size of the CsI detectors is 7 cm×7 cm, and we need at least 16 CsI detectors to cover a 0° to 5° angular distribution.

Guo, Chen-Lei; Zhang, Gao-Long; Tanihata, I.; Le, Xiao-Yun

2012-03-01

226

Polarizable interaction potential for water from coupled cluster calculations. I. Analysis of dimer potential energy surface  

E-print Network

Polarizable interaction potential for water from coupled cluster calculations. I. Analysis of dimer online 7 March 2008 A six-dimensional interaction potential for the water dimer has been fitted to ab potential energy surface Robert Bukowski,1 Krzysztof Szalewicz,1,a Gerrit C. Groenenboom,2 and Ad van der

227

Microscopic self-energy calculations and dispersive optical-model potentials  

E-print Network

Nucleon self-energies for 40Ca, 48Ca, 60Ca isotopes are generated with the microscopic Faddeev-random-phase approximation (FRPA). These self-energies are compared with potentials from the dispersive optical model (DOM) that were obtained from fitting elastic-scattering and bound-state data for 40Ca and 48Ca. The \\textit{ab initio} FRPA is capable of explaining many features of the empirical DOM potentials including their nucleon asymmetry dependence. The comparison furthermore provides several suggestions to improve the functional form of the DOM potentials, including among others the exploration of parity and angular momentum dependence. The non-locality of the FRPA imaginary self-energy, illustrated by a substantial orbital angular momentum dependence, suggests that future DOM fits should consider this feature explicitly. The roles of the nucleon-nucleon tensor force and charge-exchange component in generating the asymmetry dependence of the FPRA self-energies are explored. The global features of the FRPA s...

Waldecker, S J; Dickhoff, W H

2011-01-01

228

Potential energy savings on the MIT campus  

E-print Network

The MIT community and the City of Cambridge embarked on initiatives to reduce energy consumption and Greenhouse Gas emissions in accordance with the Kyoto Protocol which calls for a 20 % reduction in 1990 levels of GHG ...

Amanti, Steven Thomas

2006-01-01

229

Exact Description of Rotational Waves in an Elastic Solid  

E-print Network

Conventional descriptions of transverse waves in an elastic solid are limited by an assumption of infinitesimally small gradients of rotation. By assuming a linear response to variations in orientation, we derive an exact description of a restricted class of rotational waves in an ideal isotropic elastic solid. The result is a nonlinear equation expressed in terms of Dirac bispinors. This result provides a simple classical interpretation of relativistic quantum mechanical dynamics. We construct a Lagrangian of the form L=-E+U+K=0, where E is the total energy, U is the potential energy, and K is the kinetic energy.

R. A. Close

2009-08-22

230

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

231

Elastic differential cross sections for C4F6 isomers in the 1.5-200 eV energy electron impact: Similarities with six fluorine containing molecules and evidence of F-atom like scattering  

NASA Astrophysics Data System (ADS)

We report absolute elastic differential cross sections for electron interactions with the C4F6 isomers, hexafluoro-1,3-butadiene (1,3-C4F6), hexafluoro-2-butyne (2-C4F6), and hexafluorocyclobutene (c-C4F6). The incident electron energy range is 1.5-200 eV, and the scattered electron angular range for the differential measurements varies from 15° to 150°. In all cases the absolute scale of the differential cross section was set using the relative flow technique, with helium as the reference species. Atomic-like behaviour in these scattering systems is shown here for the first time, and is further investigated by comparing the elastic cross sections for the C4F6 isomers with other fluorinated molecules, such as SF6 and CnF6 (n = 2, 3, and 6). We note that for all the six-F containing molecules, the scattering process for electron energies above 30 eV is indistinguishable. Finally, we report results for calculations of elastic differential cross sections for electron scattering from each of these isomers, within an optical potential method and assuming a screened corrected independent atom representation. The level of agreement between these calculations and our measurements is found to be quite remarkable in all cases.

Hoshino, M.; Limão-Vieira, P.; Anzai, K.; Kato, H.; Cho, H.; Mogi, D.; Tanioka, T.; Ferreira da Silva, F.; Almeida, D.; Blanco, F.; García, G.; Ingólfsson, O.; Tanaka, H.

2014-09-01

232

Elastic differential cross sections for C4F6 isomers in the 1.5-200 eV energy electron impact: Similarities with six fluorine containing molecules and evidence of F-atom like scattering.  

PubMed

We report absolute elastic differential cross sections for electron interactions with the C4F6 isomers, hexafluoro-1,3-butadiene (1,3-C4F6), hexafluoro-2-butyne (2-C4F6), and hexafluorocyclobutene (c-C4F6). The incident electron energy range is 1.5-200 eV, and the scattered electron angular range for the differential measurements varies from 15° to 150°. In all cases the absolute scale of the differential cross section was set using the relative flow technique, with helium as the reference species. Atomic-like behaviour in these scattering systems is shown here for the first time, and is further investigated by comparing the elastic cross sections for the C4F6 isomers with other fluorinated molecules, such as SF6 and CnF6 (n = 2, 3, and 6). We note that for all the six-F containing molecules, the scattering process for electron energies above 30 eV is indistinguishable. Finally, we report results for calculations of elastic differential cross sections for electron scattering from each of these isomers, within an optical potential method and assuming a screened corrected independent atom representation. The level of agreement between these calculations and our measurements is found to be quite remarkable in all cases. PMID:25273432

Hoshino, M; Limão-Vieira, P; Anzai, K; Kato, H; Cho, H; Mogi, D; Tanioka, T; Ferreira da Silva, F; Almeida, D; Blanco, F; García, G; Ingólfsson, O; Tanaka, H

2014-09-28

233

ECONOMIC DEVELOPMENT POTENTIAL OF CONVENTIONAL AND POTENTIAL ALTERNATIVE ENERGY SOURCES IN APPALACHIAN COUNTIES  

Microsoft Academic Search

Appalachia has significant potential to contribute to both national energy independence and to achieve regional import substitution in the energy sector. There are significant opportunities for regional and community- scaled industrial development, especially in the areas of bio-fuels. Major choices exist in the selection of a minimum scale of production for many of the new technologies and energy sources. Technologies

Amy Glasmeier; Tom Bell

234

Saturation wind power potential and its implications for wind energy  

E-print Network

Saturation wind power potential and its implications for wind energy Mark Z. Jacobsona,1 to determine the maximum theo- retical wind power potential on Earth, based on the concept of "saturation". The saturation wind power potential (SWPP) is the maximum wind power that can be extracted upon increasing

235

The elastic fibre network of the human lumbar anulus fibrosus: architecture, mechanical function and potential role in the progression of intervertebral disc degeneration  

Microsoft Academic Search

Elastic fibres are critical constituents of dynamic biological structures that functionally require elasticity and resilience.\\u000a The network of elastic fibres in the anulus fibrosus of the intervertebral disc is extensive, however until recently, the\\u000a majority of histological, biochemical and biomechanical studies have focussed on the roles of other extracellular matrix constituents\\u000a such as collagens and proteoglycans. The resulting lack of

Lachlan J. Smith; Nicola L. Fazzalari

2009-01-01

236

Renewable energy potential and utilization in Turkey  

Microsoft Academic Search

Renewable energy sources have been important for humans since the beginning of civilisation. For centuries, and in many ways, biomass has been used for heating, and cooking. Many centuries ago, mankind was already utilizing the clearly visible power of water for mechanical drive purposes, as was also the case with wind. Today, water mills are still used in our villages,

Kamil Kaygusuz; Ahmet Sar?

2003-01-01

237

Energy potential of leafy spurge ( Euphorbia esula )  

Microsoft Academic Search

Leafy spurge (Euphorbia esula) is a noxious, perennial weed that infests pastures, rangeland and waste areas in the northern Great Plains. The objective\\u000a of this study was to determine the productive potential of this species when grown under optimum agronomic conditions. Plants\\u000a were fertilized and irrigated. Oil, hydrocarbon, total protein, and dry-weight production were measured on 3 harvest dates.\\u000a Calorimetric

B. D. Maxwell; S. M. Wiatr; P. K. Fay

1985-01-01

238

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

239

Geothermal energy—A sustainable resource of enormous potential  

NASA Astrophysics Data System (ADS)

Geothermal energy is available at many locations on the earth’s surface. This clean and reliable energy has enormous potential and can be used to partially replace the conventional fuels that are currently used; the total magnitude of this resource is much larger than the potential contained in all of the fossil and uranium reserves worldwide. Geothermal energy will become increasingly significant during the next century; enhanced thermal energy R&D is expected to lead to commercial development some time after 2010, depending on energy costs at that time.

Wright, P. M.

1998-12-01

240

Potential of renewable energy development for water desalination in Tunisia  

Microsoft Academic Search

Potential renewable energy sources, which can be harnessed toward brackish and seawater desalination in Tunisia, have been evaluated. These sources of energy, mainly: solar, wind and geothermal, have been identified throughout the country and their suitability for coupling with different desalting technologies have been investigated. Renewable energies are expected to have a flourishing future and an important role in the

F Benjemaa; I Houcine; M. H Chahbani

1999-01-01

241

Ocean Thermal Energy Conversion: Potential Environmental Impacts and Fisheries  

E-print Network

Ocean Thermal Energy Conversion: Potential Environmental Impacts and Fisheries Christina M Comfort Institute #12;Ocean Thermal Energy Conversion (OTEC) · Renewable energy ­ ocean thermal gradient · Large shock · Plume ­ Changes in local conditions ­ Aquaculture? ­ FAD effects + enhanced productivity? #12

Hawai'i at Manoa, University of

242

Rivers of energy: the hydropower potential. [Monograph  

SciTech Connect

Hydropower, aproven technology that provides 25% of the world's electricity, often has been overlooked by energy planners. Hydropower emits no health-threatening pollutants, produces no harmful wastes, and can be planned to cause minimal damage to the landscape. An overview of the long history of hydropower is followed by an analysis of the opportunities and problems associated with developing water resources. Small-scale hydro in developing countries and in remote areas opens new opportunities for investment and future development. The opportunities in developed countries are primarily in upgrading and rehabilitating existing facilities. New directions are needed to take advantage of the world's hydropower resources: (1) developing countries need to plan a balance of large and small sites, while developed countries should concentrate on small sites; (2) new pricing and allocation policies are needed to discourage waste and to reflect the transition to a new energy era. 87 references, 2 figures, 2 tables. (DCK)

Deudney, D.

1981-01-01

243

Muscle Function in vivo: A Comparison of Muscles used for Elastic Energy Savings versus Muscles Used to Generate Mechanical Power 1  

Microsoft Academic Search

SYNOPSIS. The function of muscles used to generate force economically and facil- itate elastic energy savings in their tendons is compared with muscles that function to produce mechanical power. The underlying architectural design of the muscle and its tendon (if present) dictate much of their functional capacity and role in animal locomotion. Using methods that allow direct recordings of muscle

ANDRE W A. BIEWENER

2010-01-01

244

Ocean thermal energy: Potentials and pitfalls  

Microsoft Academic Search

Thermal energy in vast reaches of the world's oceans lies waiting to be tapped by a fuel?hungry world. The United States— the one heavily industrialized nation with “OTEC”; waters lapping its shores—is actively developing the technology; Japan and a European consortium are also pressing forward. The resource may be of practical value soon to favorably situated islands (e.g., Hawaii, Puerto

David L. Hurwood

1981-01-01

245

Periodic Discrete Energy for Long-Range Potentials  

E-print Network

We consider periodic energy problems in Euclidean space with a special emphasis on long-range potentials that cannot be defined through the usual infinite sum. One of our main results builds on more recent developments of Ewald summation to define the periodic energy corresponding to a large class of long-range potentials. Two particularly interesting examples are the logarithmic potential and the Riesz potential when the Riesz parameter is smaller than the dimension of the space. For these examples, we use analytic continuation methods to provide concise formulas for the periodic kernel in terms of the Epstein Hurwitz Zeta function. We apply our energy definition to deduce several properties of the minimal energy including the asymptotic order of growth and the distribution of points in energy minimizing configurations as the number of points becomes large. We conclude with some detailed calculations in the case of one dimension, which shows the utility of this approach.

D. P. Hardin; E. B. Saff; Brian Simanek

2014-03-28

246

ELASTICITYELASTICITY Elasticity  

E-print Network

K We have noted that elastic modulus is a 4th rank tensor (with 81 components in general in 3D temperatures Phenomenologically mechanical behaviour can be understood as in the flow diagram below. Multiple mechanisms may be associated with these phenomena (e.g. creep can occur by diffusion, grain boundary sliding

Subramaniam, Anandh

247

Exploring for the Sources of Internal Elastic Deformations Using Potential Fields and Their Poisson Wavelets; Possible Applications to InSAR Observations  

Microsoft Academic Search

From a restricted solution of the Cauchy-Navier equations of quasi-static infinitesimal elasticity theory [Green and Zerna, 1968, section 5.7] for an isotropic, linear elastic half-space with a shear-traction free ground surface, we find a scalar function rho that is present underground wherever internal deformations are generated, and absent elsewhere. The \\

F. G. Horowitz; P. Hornby

2006-01-01

248

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

249

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

250

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

251

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

252

Generalized Berreman's model of the elastic surface free energy of a nematic liquid crystal on a sawtoothed substrate.  

PubMed

In this paper we present a generalization of Berreman's model for the elastic contribution to the surface free-energy density of a nematic liquid crystal in presence of a sawtooth substrate which favors homeotropic anchoring as a function of the wave number of the surface structure q, the tilt angle ?, and the surface anchoring strength w. In addition to the previously reported nonanalytic contribution proportional to -q ln q, due to the nucleation of disclination lines at the wedge bottoms and apexes of the substrate, the next-to-leading contribution is proportional to q for a given substrate roughness, in agreement with Berreman's predictions. We characterize this term, finding that it has two contributions: the deviations of the nematic director field with respect to a reference field corresponding to the isolated disclination lines and their associated core free energies. Comparison with the results obtained from the Landau-de Gennes model shows that our model is quite accurate in the limit wL>1, when strong anchoring conditions are effectively achieved. PMID:23214602

Rojas-Gómez, O A; Romero-Enrique, J M

2012-10-01

253

Noise activated dissociation of soft elastic contacts  

E-print Network

Adhesive forces are capable of deforming a soft elastic object when it comes in contact with a flat rigid substrate. The contact is in stable equilibrium if the total energy of the system arising from the elastic and surface forces exhibits a minimum at a zero or at a slightly negative load. However, as the system is continually unloaded, the energy barrier decreases and it eventually disappears, thus leading to a ballistic separation of the contact. While this type of contact splitting has received wide recognition, what has not been much appreciated with these types of soft adhesion problems is that rupture of a contact can also occur at any finite sub critical load in the presence of a noise. The soft contact problems are unique in that the noise can be a-thermal, whereas the metastable and stable states of the thermodynamic potential can arise from the competition of the elastic and the inter-facial energies of the system. Analysis based on activated rate theory and simulations based on stochastic dynamics show that the contact rupture dynamics is amenable to a force and noise induced escape of a particle from a potential well that is generic to various types of colloidal and macromolecular processes. These ideas are useful in understanding the results of a recent experiment involving the noise activated rolling dynamics of a rigid sphere on a surface, where it is pinned by soft micro-fibrils.

M. K. Chaudhury; P. S. Goohpattader

2014-02-03

254

Potential energy stored by planets and grand minima events  

NASA Astrophysics Data System (ADS)

Recently, Wolff & Patrone (2010), have developed a simple but very interesting model by which the movement of the Sun around the barycentre of the Solar system could create potential energy that could be released by flows pre-existing inside the Sun. The authors claim that it is the first mechanism showing how planetary movements can modify internal structure in the Sun that can be related to solar cycle. In this work we point out limitations of mentioned mechanism (which is based on interchange arguments), which could be inapplicable to a real star. Then, we calculate the temporal evolution of potential energy stored in zones of Sun's interior in which the potential energy could be most efficiently stored taking into account detailed barycentric Sun dynamics. We show strong variations of potential energy related to Maunder Minimum, Dalton Minimum and the maximum of Cycle 22, around 1990. We discuss briefly possible implications of this putative mechanism to solar cycle specially Grand Minima events.

Cionco, Rodolfo G.

2012-07-01

255

Opinion Biomass energy: the scale of the potential resource  

E-print Network

Increased production of biomass for energy has the potential to offset substantial use of fossil fuels, but it also has the potential to threaten conservation areas, pollute water resources and decrease food security. The net effect of biomass energy agriculture on climate could be either cooling or warming, depending on the crop, the technology for converting biomass into useable energy, and the difference in carbon stocks and reflectance of solar radiation between the biomass crop and the preexisting vegetation. The area with the greatest potential for yielding biomass energy that reduces net warming and avoids competition with food production is land that was previously used for agriculture or pasture but that has been abandoned and not converted to forest or urban areas. At the global scale, potential above-ground

Christopher B. Field; J. Elliott Campbell; David B. Lobell

256

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

257

Comparison of elastic scattering spectroscopy with histology in ex vivo prostate glands: potential application for optically guided biopsy and directed treatment.  

PubMed

The false-negative rate of ultrasound-guided sextant prostate biopsy has been estimated to be as high as 35 %. A significant percentage (10-35 %) of these prostate cancers diagnosed at a second or later attempt are high grade and, therefore, potentially lethal. We discuss the feasibility for performing optically guided biopsy using elastic scattering spectroscopy (ESS) to reduce sampling errors and improve sensitivity. ESS measurements were performed on 42 prostate glands ex vivo and correlated with standard histopathological assessment. Sliced glands were examined with wavelength ranges of 330-760 nm. The ESS portable system used a new fiber-optic probe with integrated cutting tool, designed specifically for ex vivo pathology applications. ESS spectra were grouped by diagnosis from standard histopathological procedure and then classified using linear support vector machine. Preliminary data are encouraging. ESS data showed strong spectral trends correlating with the histopathological assignments. The classification results showed a sensitivity of 0.83 and specificity of 0.87 for distinguishing dysplastic prostatic tissue from benign prostatic tissue. Similar results were obtained for distinguishing dysplastic prostatic tissue from prostatitis with a sensitivity and specificity of 0.80 and 0.88, respectively. The negative predictive values obtained with ESS are better than those obtained with transrectal ultrasound (TRUS)-guided core-needle biopsy. PMID:23247663

A'Amar, O M; Liou, L; Rodriguez-Diaz, E; De las Morenas, A; Bigio, I J

2013-09-01

258

DESIGN AND VALIDATION OF A HIGH ENERGY DENSITY ELASTIC ACCUMULATOR USING POLYURETHANE  

E-print Network

.j.barth@vanderbilt.edu ABSTRACT Hydraulic accumulators (HAs) have been used successfully in regenerative braking systems application of these devices is regenerative braking. A conventional braking system uses friction between. In contrast, regenerative braking harnesses the kinetic energy of a vehicle during braking, instead of letting

Barth, Eric J.

259

Potential energy: An analysis of world energy technology  

Microsoft Academic Search

General conditions concerning the available energy sources for the world's economy are examined, taking into account the growth in world energy consumption over the period from 1962 to 1972. New uses of coal are considered along with aspects of gasification and liquefaction. Prospects concerning a use of nuclear fission are investigated, taking into account thermal reactors, breeder reactors, the fuel

M. Kenward

1976-01-01

260

Investigating energy-saving potentials in the cloud.  

PubMed

Collecting webpage messages can serve as a sensor for investigating the energy-saving potential of buildings. Focusing on stores, a cloud sensor system is developed to collect data and determine their energy-saving potential. The owner of a store under investigation must register online, report the store address, area, and the customer ID number on the electric meter. The cloud sensor system automatically surveys the energy usage records by connecting to the power company website and calculating the energy use index (EUI) of the store. Other data includes the chain store check, company capital, location price, and the influence of weather conditions on the store; even the exposure frequency of store under investigation may impact the energy usage collected online. After collecting data from numerous stores, a multi-dimensional data array is constructed to determine energy-saving potential by identifying stores with similarity conditions. Similarity conditions refer to analyzed results that indicate that two stores have similar capital, business scale, weather conditions, and exposure frequency on web. Calculating the EUI difference or pure technical efficiency of stores, the energy-saving potential is determined. In this study, a real case study is performed. An 8-dimensional (8D) data array is constructed by surveying web data related to 67 stores. Then, this study investigated the savings potential of the 33 stores, using a site visit, and employed the cloud sensor system to determine the saving potential. The case study results show good agreement between the data obtained by the site visit and the cloud investigation, with errors within 4.17%. Among 33 the samples, eight stores have low saving potentials of less than 5%. The developed sensor on the cloud successfully identifies them as having low saving potential and avoids wasting money on the site visit. PMID:24561405

Lee, Da-Sheng

2014-01-01

261

Geospatial Analysis of Renewable Energy Technical Potential on Tribal Lands  

SciTech Connect

This technical report uses an established geospatial methodology to estimate the technical potential for renewable energy on tribal lands for the purpose of allowing Tribes to prioritize the development of renewable energy resources either for community scale on-tribal land use or for revenue generating electricity sales.

Doris, E.; Lopez, A.; Beckley, D.

2013-02-01

262

Feature Article Exploring Potential Energy Surfaces for Chemical  

E-print Network

, properties, and reactivities. Recent advances in tools for exploring potential energy surfaces are surveyed in the Born-Oppenheimer and Car-Parrinello approaches are described. © 2003 Wiley Periodicals, Inc. J Comput, polarizability, NMR shielding, etc., depend on the response of the energy to applied electric and magnetic fields

Schlegel, H. Bernhard

263

Brazilian waste potential: energy, environmental, social and economic benefits  

Microsoft Academic Search

The potential energy that could be produced from solid wastes in Brazil tops 50TWh. Equivalent to some 17% of the nation's total power consumption at costs that are competitive with more traditional options, this would also reduce greenhouse gases emissions. Moreover, managing wastes for energy generation purposes could well open up thousands of jobs for unskilled workers. Related to power

Luciano Basto Oliveira; Luiz Pinguelli Rosa

2003-01-01

264

DoD energy vulnerabilities: potential problems and observations  

SciTech Connect

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

265

Elastic scattering of high-energy electrons by dopant atoms within a crystal in transmission electron microscopy.  

PubMed

A Bloch-wave model of dopant-atom scattering is developed using perturbation theory for parallel illumination in a transmission electron microscope. Dopant-atom scattering causes a change in the Bloch-wave excitations, with transitions from one Bloch state to another being governed by the amplitudes of the Bloch states at the dopant-atom position. The scattering mechanisms therefore depend on whether the dopant atom is substitutional or interstitial as well as the orientation of the crystal. The model is used to calculate the electron wavefunction for substitutional and interstitial Mo atoms in [111]- and [001]-oriented body-centred cubic Fe and the results overall are consistent with multislice simulations. However, subtle differences are also observed. For example, in the Bloch-wave model the phase change of the incident electrons (with respect to the perfect crystal) due to dopant-atom scattering varies with the crystallographic orientation while in multislice theory the phase change is constant. This is likely to be due to the assumptions made in the Bloch-wave model, such as neglect of elastic diffuse scattering. Apart from providing a fundamental understanding of dopant-atom scattering, the model can also potentially be extended to analyse dopant-atom imaging in a scanning transmission electron microscope. PMID:18931417

Mendis, B G

2008-11-01

266

Potential energy surface for spin-polarized rubidium trimer  

Microsoft Academic Search

Potential energy surface for the lowest quartet state of the rubidium trimer is constructed, making use of the many-body decomposition. Interaction energies are calculated using the coupled-clusters method and interpolated using the reciprocal-power reproducing kernel Hilbert space interpolation method. Both the two-body and three-body nonadditive parts are extrapolated to exhibit the correct long-range behavior. Consequences for the low-energy scattering are

Pavel Solda´n; Ke Karlovu

2010-01-01

267

Analysis of elastic scattering of {sup 16}O+{sup 28}Si and {sup 12}C+{sup 24}Mg by a new optical potential  

SciTech Connect

We construct a new phenomenological nucleus-nucleus optical potential based on the interesting potential developed by Ginocchio that has the versatility to control the surface and volume regions of the potential. Using this potential with suitable energy dependence of some of the parameters, we are able to fit remarkably well experimental results of the differential scattering cross section for the {sup 16}O+{sup 28}Si system in the center-of-mass energy E{sub c.m.} range from 18.67 to 90.681 MeV and the excitation function in the E{sub c.m.} range from 13.0 to 52.0 MeV. We also fit equally well the exhaustive experimental differential scattering data available for the {sup 12}C+{sup 24}Mg system in the E{sub c.m.} range from 10.67 to 16.0 MeV. The new optical potential used has significantly fewer parameters. The results are interpreted in terms of wave mechanical aspects leading to superposition of partial waves undergoing different phase shifts generated by an optical potential characterized by volume and surface parts.

Mallick, G.S. [Department of Physics, Khallikote College, Berhampur 760 001 (India); Agarwalla, S.K.; Sahu, B. [Department of Physics, North Orissa University, Baripada 757 003 (India); Shastry, C.S. [Department of Physics, Amrita Vishwa Vidyapeetham, Coimbatore 641 105 (India)

2006-05-15

268

Waves and energy in random elastic guided media through the stochastic wave finite element method  

NASA Astrophysics Data System (ADS)

Energy propagation in random viscoelastic media is considered in this Letter. The forced response of uncertain waveguide subject to time harmonic loading is treated. This energy model is based on a spectral approach called the “Stochastic Wave Finite Element” (SWFE) method which is detailed in this Letter. Assuming that the random properties are spatially homogeneous in the media, the SWFE is a hybridization of the deterministic wave finite element and a parametric probabilistic approach. The proposed model is applicable in a wide frequency band with reduced time consumption. Numerical examples show the effectiveness of the proposed approach to predict the statistics of kinematic and quadratic variables of guided wave propagation. The results are compared to Monte Carlo simulations.

Ben Souf, M. A.; Bareille, O.; Ichchou, M. N.; Bouchoucha, F.; Haddar, M.

2013-11-01

269

Dark energy exponential potential models as curvature quintessence  

E-print Network

It has been recently shown that, under some general conditions, it is always possible to find a fourth order gravity theory capable of reproducing the same dynamics of a given dark energy model. Here, we discuss this approach for a dark energy model with a scalar field evolving under the action of an exponential potential. In absence of matter, such a potential can be recovered from a fourth order theory via a conformal transformation. Including the matter term, the function f(R) entering the generalized gravity Lagrangian can be reconstructed according to the dark energy model.

S. Capozziello; V. F. Cardone; E. Piedipalumbo; C. Rubano

2005-07-19

270

Calculations of Potential Energy Surfaces Using Monte Carlo Configuration Interaction  

E-print Network

We apply the method of Monte Carlo configuration interaction (MCCI) to calculate ground-state potential energy curves for a range of small molecules and compare the results with full configuration interaction. We show that the MCCI potential energy curve can be calculated to relatively good accuracy, as quantified using the non-parallelity error, using only a very small fraction of the FCI space. In most cases the potential curve is of better accuracy than its constituent single-point energies. We finally test the MCCI program on systems with basis sets beyond full configuration interaction: a lattice of fifty hydrogen atoms and ethylene. The results for ethylene agree fairly well with other computational work while for the lattice of fifty hydrogens we find that the fraction of the full configuration interaction space we were able to consider appears to be too small as, although some qualitative features are reproduced, the potential curve is less accurate.

Coe, J P; Paterson, M J; 10.1063/1.4767052

2012-01-01

271

On the nuclear interaction. Potential, binding energy and fusion reaction  

E-print Network

The nuclear interaction is responsible for keeping neutrons and protons joined in an atomic nucleus. Phenomenological nuclear potentials, fitted to experimental data, allow one to know about the nuclear behaviour with more or less success where quantum mechanics is hard to be used. A nuclear potential is suggested and an expression for the potential energy of two nuclear entities, either nuclei or nucleons, is developed. In order to estimate parameters in this expression, some nucleon additions to nuclei are considered and a model is suggested as a guide of the addition process. Coulomb barrier and energy for the addition of a proton to each one of several nuclei are estimated by taking into account both the nuclear and electrostatic components of energy. Studies on the binding energies of several nuclei and on the fusion reaction of two nuclei are carried out.

I. Casinos

2008-05-22

272

Free energy and direct photon emission at finite chemical potential  

NASA Astrophysics Data System (ADS)

We investigate the evolution of free energy and direct photon production from quark-gluon plasma (QGP) considering finite chemical potential. The evolution of QGP formation at the chemical potential is done through finite value of quark mass. The evolution rate is found to be decreasing with chemical potential. We further study the direct photon emission from the fireball of such QGP and found the result to be increasing function of chemical potential in all the channels of photon production. It also shows enhancement of photon emission in comparison to the other theoretical calculation of direct photon productions.

Somorendro Singh, S.

2014-09-01

273

Potential for energy conservation in the glass industry  

SciTech Connect

While the glass industry (flat glass, container glass, pressed and blown glass, and insulation fiber glass) has reduced its specific energy use (Btu/ton) by almost 30% since 1972, significant potential for further reduction still remains. State-of-the-art technologies are available which could lead to incremental improvements in glass industry energy productivity; however, these technologies must compete for capital with projects undertaken for other reasons (e.g., capacity expansion, equipment rebuild, labor cost reduction, product quality improvement, or compliance with environmental, health or safety regulations). Narrowing profit margins in the large tonnage segments of the glass industry in recent years and the fact that energy costs represent less than 25% of the value added in glass manufacture have combined to impede the widespread adoption of many state-of-the-art conservation technologies. Savings in energy costs alone have not provided the incentive to justify the capital expenditures required to realize the energy savings. Beyond implementation of state-of-the-art technologies, significant potential energy savings could accrue from advanced technologies which represent a radical departure from current glass making technology. Long-term research and development (R and D) programs, which address the technical and economic barriers associated with advanced, energy-conserving technologies, offer the opportunity to realize this energy-saving potential.

Garrett-Price, B.A.; Fassbender, A.G.; Bruno, G.A.

1986-06-01

274

Potential impact of energy farming for conserving the fossil-fuel energy requirements of food production  

Microsoft Academic Search

The potential of supplying the energy requirements for food production by utilizing waste biomass was investigated. It was found that the energy available was more than sufficient even after conversion of waste biomass to more versatile fuel forms. The concept of utilizing waste biomass has the potential for conserving fossil fuels. Only the energy balance aspects of utilizing waste biomass

R. C. Bailie; D. M. Doner; J. D. Henry

1976-01-01

275

Direct evaluation of composition profile, strain relaxation, and elastic energy of Ge:Si(001) self-assembled islands by anomalous x-ray scattering  

NASA Astrophysics Data System (ADS)

The growth of strained epitaxial self assembled nanocrystals is comprised of a variety of kinetic and thermodynamic factors that determine their morphology and size. Some of the significant factors to their stability are strain and interdiffusion. Here we directly measure the gradient of composition and strain in Ge nanocrystals grown on Si(001) using anomalous x-ray scattering. By combining our x-ray results, where we relate strain, interdiffusion, and shape with atomic force microscopy measurements, we have been able to determine the complete strain configuration of these islands. We show that the amount of elastic energy in pyramids and domes can be evaluated. The transition from pyramids to domes is accompanied by an increase of lattice parameter and enhancement of interdiffusion, both leading to a drastic decrease of the elastic energy stored per atom.

Magalhães-Paniago, R.; Medeiros-Ribeiro, G.; Malachias, A.; Kycia, S.; Kamins, T. I.; Williams, R. Stan

2002-12-01

276

Elastic scattering of nuclear systems induced by weakly bound projectiles  

NASA Astrophysics Data System (ADS)

The influence of the breakup channel on the elastic scattering and on the fusion process for systems that involve weakly bound stable nuclei has been widely investigated in the last years. One of the most used approaches to address these problems is to investigate the energy dependence of the nuclear interaction potential. For tightly bound systems at energies close to the Coulomb barrier, this energy dependence exhibits the behavior known as threshold anomaly. On the other hand, for various weakly bound systems the nuclear potential as a function of energy has a completely different behavior known as breakup threshold anomaly. In this report we present an overview of the subject discussing the different experimental measurements and theoretical interpretations that have been published. In this framework, we present the results of the elastic scattering cross sections for the 6,7Li+80Se systems that have been recently measured at the TANDAR laboratory and we discuss the conclusions obtained from these studies.

Martí, G. V.; Fimiani, L.; Figueira, J. M.; Testoni, J. E.; Arazi, A.; Capurro, O. A.; Cárdenas, W. H. Z.; Cardona, M. A.; Carnelli, P.; de Barbará, E.; Hojman, D.; Heimann, D. Martinez; Negri, A.; Pacheco, A. J.

2012-02-01

277

Saturation wind power potential and its implications for wind energy  

PubMed Central

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.

2012-01-01

278

Elastic softening in nanocrystalline silicon  

SciTech Connect

It is pointed out that some of the generic physical properties of a nanocrystalline material are similar to those of a grain-boundary superlattice. The structure and elastic properties of a superlattice of twist boundaries on the (110) plane of silicon are calculated as a function of modulation wavelength using a three-body potential. All elastic moduli are found to be softened. This softening is attributed to the relatively small amount of structural disorder at the interfaces. 8 refs., 4 figs.

Phillpot, S.R.; Wolf, D.; Lutsko, J.F.

1989-05-01

279

Energy and water potential of the Southeastern Anatolia Project (GAP)  

SciTech Connect

This article gives an overview of energy and water potential of the Southeastern Anatolia Project (GAP) in Turkey. This integrated socioeconomic development project is one of the largest of its kind in the world. The GAP region is rich in water and soil resources. The Euphrates and Tigris Rivers represent over 28% of the nation's water supply by rivers, and the economically irrigatable areas in the region make up 20% of those for the entire country. On the other hand, the GAP region is the richest region of the country in terms of its hydroelectric potential as well as its oil and asphalt reserves. The GAP region has a 22% share of the country's total hydroelectric potential, with plans for 22 dams and 19 hydropower plants. Once completed, 27 billion kWh of electricity will be generated. In addition to this hydropower and oil potential, the GAP region is also the richest region of Turkey as far as solar energy production is concerned. In meeting the energy requirements of the developing regions worldwide and in Turkey, solar energy is being taken into account as an important renewable source of energy.

Kaygusuz, K.

1999-12-01

280

Wayside energy storage for recuperation of potential energy from freight trains  

SciTech Connect

The subject of this paper, involves the potential for use of a wayside energy storage system to recapture part of the braking energy normally dissipated on long descending grades by freight trains employing dynamic braking. 4 refs.

Lawson, L.J.; Koper, J.; Cook, L.M.

1981-01-01

281

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

282

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

283

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

284

Reaction Path Optimization with Holonomic Constraints and Kinetic Energy Potentials  

SciTech Connect

Two methods are developed to enhance the stability, efficiency, and robustness of reaction path optimization using a chain of replicas. First, distances between replicas are kept equal during path optimization via holonomic constraints. Finding a reaction path is, thus, transformed into a constrained optimization problem. This approach avoids force projections for finding minimum energy paths (MEPs), and fast-converging schemes such as quasi-Newton methods can be readily applied. Second, we define a new objective function - the total Hamiltonian - for reaction path optimization, by combining the kinetic energy potential of each replica with its potential energy function. Minimizing the total Hamiltonian of a chain determines a minimum Hamiltonian path (MHP). If the distances between replicas are kept equal and a consistent force constant is used, then the kinetic energy potentials of all replicas have the same value. The MHP in this case is the most probable isokinetic path. Our results indicate that low-temperature kinetic energy potentials (<5 K) can be used to prevent the development of kinks during path optimization and can significantly reduce the required steps of minimization by 2-3 times without causing noticeable differences between a MHP and MEP. These methods are applied to three test cases, the C?eq-to-Cax isomerization of an alanine dipeptide, the ?C?- to-¹C? transition of an ?-D-glucopyranose, and the helix-to-sheet transition of a GNNQQNY heptapeptide. By applying the methods developed in this work, convergence of reaction path optimization can be achieved for these complex transitions, involving full atomic details and a large number of replicas (>100). For the case of helix-to-sheet transition, we identify pathways whose energy barriers are consistent with experimental measurements. Further, we develop a method based on the work energy theorem to quantify the accuracy of reaction paths and to determine whether the atoms used to define a path are enough to provide quantitative estimation of energy barriers.

Brokaw, Jason B.; Haas, Kevin R.; Chu, Jhih-wei

2009-08-11

285

Non-parametric Image Registration Using Generalized Elastic Nets  

E-print Network

elastic nets. The concept behind the algorithm is to adapt an elastic net in spatial-intensity space and recovers underlying image deformation, which can be arbitrary. Representation of elastic net in the spatial for optimization of elastic net energy is developed. The accuracy and effectiveness of the method is demonstrated

Boyer, Edmond

286

The trajectory of a stiff rod in a curved potential energy trough. An initial result for short nucleosomal rods.  

PubMed

The equilibrium trajectory of the axis of a rod subject to an externally imposed curved potential energy trough tends to conform to the shape of the curved trough, but also tends to be straight because of elastic resistance to bending. The actual path of the axis is a balance between the two extremes. We consider a potential energy trough centered along a circular arc of radius R. For a rod of small length compared to R, we show that the axis at equilibrium forms an arc of a circle of radius greater than R. The value of the radius of the axial path depends on the relative values of the Hooke's Law bending constant for the rod and the depth and width of the trough. Motivation for the calculation is provided by nucleosomal DNA, which conforms to the surface of a roughly cylindrical histone core at physiological ionic strength, but is observed to unwind into a partially extended conformation at very low ionic strength. We suggest that the rigidity to bending of short DNA segments becomes sufficiently great at low ionic strength to overcome attractive interactions with the histone surface. Alternately, of course, if during the cell cycle mutually attractive forces between DNA and histone core are weakened at constant ionic strength, the same type of unfolding would be expected to occur as the strength of the DNA-histone contacts drops below the level required to overcome elastic resistance to bending of the DNA rod. PMID:2416444

Manning, G S

1985-09-01

287

Price elasticity for gasoline revisited  

SciTech Connect

A reexamination of the 1974 findngs of Houthakker, Verleger, and Sheehan confirms that gasoline prices can promote energy conservation and that demand responses devlop over time. The empirical evidence is consistent with other earlier studies. The responsiveness observed during the 1962 to 73 sample period probably understates present economic elasticity because gasoline prices now require a larger share of disposable income, making a -1.5 price elasticity more realistic. 8 references, 1 table. (DCK)

Pelaez, R.F.

1981-10-01

288

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

289

Unified Technical Concepts. Module 7: Potential and Kinetic Energy.  

ERIC Educational Resources Information Center

This concept module on potential and kinetic energy is one of thirteen modules that provide a flexible, laboratory-based physics instructional package designed to meet the specialized needs of students in two-year, postsecondary technical schools. Each of the thirteen concept modules discusses a single physics concept and how it is applied to each…

Technical Education Research Center, Waco, TX.

290

Low energy chiral two pion exchange potential with statistical uncertainties  

E-print Network

We present a new phenomenological Nucleon-Nucleon chiral potential fitted to 925 pp and 1743 np scattering data up to a laboratory energy of $125$ MeV with 20 short distance parameters and three chiral constants $c_1$, $c_3$ and $c_4$ with $\\chi^2/\

Perez, R Navarro; Arriola, E Ruiz

2014-01-01

291

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. PMID:17350998

Gabel, Frank; Bellissent-Funel, Marie-Claire

2007-01-01

292

Potentials and policy implications of energy and material efficiency improvement  

SciTech Connect

There is a growing awareness of the serious problems associated with the provision of sufficient energy to meet human needs and to fuel economic growth world-wide. This has pointed to the need for energy and material efficiency, which would reduce air, water and thermal pollution, as well as waste production. Increasing energy and material efficiency also have the benefits of increased employment, improved balance of imports and exports, increased security of energy supply, and adopting environmentally advantageous energy supply. A large potential exists for energy savings through energy and material efficiency improvements. Technologies are not now, nor will they be, in the foreseeable future, the limiting factors with regard to continuing energy efficiency improvements. There are serious barriers to energy efficiency improvement, including unwillingness to invest, lack of available and accessible information, economic disincentives and organizational barriers. A wide range of policy instruments, as well as innovative approaches have been tried in some countries in order to achieve the desired energy efficiency approaches. These include: regulation and guidelines; economic instruments and incentives; voluntary agreements and actions, information, education and training; and research, development and demonstration. An area that requires particular attention is that of improved international co-operation to develop policy instruments and technologies to meet the needs of developing countries. Material efficiency has not received the attention that it deserves. Consequently, there is a dearth of data on the qualities and quantities for final consumption, thus, making it difficult to formulate policies. Available data, however, suggest that there is a large potential for improved use of many materials in industrialized countries.

Worrell, Ernst; Levine, Mark; Price, Lynn; Martin, Nathan; van den Broek, Richard; Block, Kornelis

1997-01-01

293

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

294

Turkey's High Temperature Geothermal Energy Resources and Electricity Production Potential  

NASA Astrophysics Data System (ADS)

Turkey is in the first 7 countries in the world in terms of potential and applications. Geothermal energy which is an alternative energy resource has advantages such as low-cost, clean, safe and natural resource. Geothermal energy is defined as hot water and steam which is formed by heat that accumulated in various depths of the Earth's crust; with more than 20oC temperature and which contain more than fused minerals, various salts and gases than normal underground and ground water. It is divided into three groups as low, medium and high temperature. High-temperature fluid is used in electricity generation, low and medium temperature fluids are used in greenhouses, houses, airport runways, animal farms and places such as swimming pools heating. In this study high temperature geothermal fields in Turkey which is suitable for electricity production, properties and electricity production potential was investigated.

Bilgin, Ö.

2012-04-01

295

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

296

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

297

Crack growth in bonded elastic half planes  

NASA Technical Reports Server (NTRS)

Two solutions were developed for the two dimensional problem of bonded linearly elastic half-planes. For each solution, numerical results are presented for the stress intensity factors, strain energy release rate, stresses, and displacements. The behavior predicted by the studies was investigated experimentally using polymers for the material pairs. Close agreement was found for the critical stress intensity factor at fracture for the perpendicular crack near the interface. Fracture along the interface proved to be inconclusive due to difficulties in obtaining a brittle bond. Some interesting and predictable behavior regarding the potential for the crack to cross the interface was observed and is discussed.

Goree, J. G.

1975-01-01

298

Recent Results on Elastic and Inelastic Scattering  

NASA Astrophysics Data System (ADS)

In this review article, which corresponds to lectures given by one of us (N.A) at the third "Euroschool on Exotic Beams" held in Leuven in September 1995, we present experimental results and theoretical developments in heavy-ion elastic and inelastic scattering and Giant Resonance excitation. The paper contains a short review of the field with special emphasis on more recent results and problems. We start by recalling the theoretical situation concerning the description of nucleon-nucleus elastic scattering. We show that in the framework of the local density approximation, complex potentials derived from fundamental effective nucleon-nucleon interactions, describe successfully the data. However, the main part of the discussion on elastic scattering, is dedicated to the description of intermediate energy heavy-ion elastic scattering. We present different folding models for the calculation of the real part of the nucleus-nucleus optical potential, M3Y, DDM3Y, .... The theoretical predictions are compared to experimental data mainly obtained at GANIL (20-100 Mev per nucleon). We show that a new density dependent interaction which reproduces the equilibrium density and the binding energy of normal nuclear matter, leads also to a satisfactory description of heavy-ion elastic scattering angular distributions. This interaction reproduces also the density and energy dependence of the nucleon optical potential. We present a new simple effective interaction with a real and imaginary part for peripheral heavy-ion collisions at intermediate energies. Finally the effect of the isospin and spin terms of the effective nucleon-nucleon interaction on the nucleus-nucleus folded potentials is discussed. We introduce the deformed optical model potential which is the most frequently used model, to obtain inelastic scattering transition potentials. However the most direct approach to obtain transition potentials is from the folding of the transition densities with an effective nucleon-nucleon interaction and the ground state density of the nucleus which is not excited. We show that the predictions of the optical and folding model are very different, especially for transitions dominated by nuclear excitation. The difference between the cross sections estimated within the deformed optical model and the folding model increases with multipolarity. Following the theoretical work of R. Satchler, we recommend the use of a folding model to extract deformation lengths and multipole moments from inelastic scattering measurements. We present the state of the field concerning Electric Giant Resonances and multiphonon excitations. We introduce the different sum rules which can be found usually in the literature and we show the link between them. The excitation of Giant Resonances with intermediate energy or high energy heavy ions, measured at GANIL or GSI and the technical problems met in the analysis of these experiments are discussed. Recent results concerning the two-phonon excitation of the Giant Quadrupole and Dipole mode are presented. Concerning the breathing mode, macroscopic and microscopic prescriptions introduced to access the compressibility of the nuclear matter are discussed. We show, in the light of theoretical arguments developed recently by J.P. Blaizot and collaborators, that microscopic calculations remain the most reliable tool for the determination of the nuclear matter compression modulus from the energy of the monopole vibration of nuclei.

Alamanos, N.; Roussel-Chomaz, P.

299

Technical Potential of Solar Energy to Address Energy Poverty and Avoid GHG Emissions in Africa  

SciTech Connect

This analysis explores the technical potential of photovoltaics (PV) or concentrating solar power (CSP) to address energy poverty in Africa through a geographic information system (GIS) screening of solar resource data developed by the U.S. Department of Energy's National Renewable Energy Laboratory (NREL).

Cowlin, S. C.; Heimiller, D.; Bilello, D.; Renne, D.

2008-01-01

300

Energy dependence of the optical potential of weakly and tightly bound nuclei as projectiles on a medium-mass target  

SciTech Connect

Angular distributions for the elastic scattering of the weakly bound {sup 6,7}Li+{sup 144}Sm systems were measured with high accuracy at bombarding energies from 85% up to 170% of the Coulomb barrier. An optical model analysis was performed, and the relevant parameters of the real and imaginary parts of the optical potential were extracted. The results are compared with those previously published for the tightly bound {sup 12}C+{sup 144}Sm and {sup 16}O+{sup 144}Sm systems. The usual threshold anomaly observed in the behavior of the potential of tightly bound systems was not observed for either weakly bound system. This absence is attributed to the repulsion due to breakup coupling which cancels the attraction arising from couplings with bound channels.

Figueira, J. M.; Arazi, A.; Carnelli, P.; Heimann, D. Martinez; Negri, A. E.; Pacheco, A. J. [Laboratorio Tandar, Comision Nacional de Energia Atomica, B1650KNA San Martin, Buenos Aires (Argentina); Consejo Nacional de Investigaciones Cientificas y Tecnicas, C1033AAJ Ciudad de Buenos Aires (Argentina); Niello, J. O. Fernandez [Laboratorio Tandar, Comision Nacional de Energia Atomica, B1650KNA San Martin, Buenos Aires (Argentina); Consejo Nacional de Investigaciones Cientificas y Tecnicas, C1033AAJ Ciudad de Buenos Aires (Argentina); Escuela de Ciencia y Tecnologia, Universidad de San Martin, B1650BWA San Martin, Buenos Aires (Argentina); Capurro, O. A.; Fimiani, L.; Marti, G. V. [Laboratorio Tandar, Comision Nacional de Energia Atomica, B1650KNA San Martin, Buenos Aires (Argentina); Lubian, J.; Monteiro, D. S.; Gomes, P. R. S. [Instituto de Fisica, Universidade Federal Fluminense, Gragoata, Niteroi, R. J., 24210-340 (Brazil)

2010-02-15

301

An assessement of global energy resource economic potentials  

E-print Network

framework, the marginal cost of energy production using every individual natural energy resource may be compared using a framework such as the LCOE at every level of natural resource use, in or- der to enable comparisons to be made. Furthermore, the poten... that are competitive compared to all al- ternatives. Since the competitiveness of cost levels change 2 with time and on the costs of alternatives, the economic potential corresponds to a quantity function of cost. How- ever, it can be used more conveniently when...

Mercure, Jean-Francois; Salas, Pablo

2012-03-20

302

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. PMID:18767086

Ess, Daniel H.; Wheeler, Steven E.; Iafe, Robert G.; Xu, Lai; Çelebi-Ölçüm, Nihan; Houk, K. N.

2009-01-01

303

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

304

Elastic response of shocked aluminum single crystals: a continuum analysis of molecular dynamics simulations  

NASA Astrophysics Data System (ADS)

Molecular dynamics (MD) simulations were used to examine elastic shock wave propagation in aluminum single crystals along [100], [110] and [111] directions using four different embedded-atom method potentials. Continuum variables extracted from MD results show that stresses, densities, and temperatures for [100] shock propagation are significantly different for the various potentials, while the results for [110] and [111] propagation are similar for three of the four potentials. Overall, the recent potential by Winey, Kubota and Gupta [MSMSE 17, 055004 (2009)] provides the best agreement with nonlinear elastic calculations that include elastic constants up to fourth order. Our MD-continuum approach provides a key step in establishing the applicability of classical MD potentials for dynamic compression. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

Zimmerman, J. A.; Winey, J. M.; Gupta, Y. M.

2011-06-01

305

Free energy generalization of the Peierls potential in iron.  

PubMed

In body-centered-cubic (bcc) crystals, 1/2<111> screw dislocations exhibit high intrinsic lattice friction as a consequence of their nonplanar core structure, which results in a periodic energy landscape known as the Peierls potential U(P). The main features determining plastic flow, including its stress and temperature dependences, can be derived directly from this potential, hence its importance. In this Letter, we use thermodynamic integration to provide a full thermodynamic extension of U(P) for bcc Fe. We compute the Peierls free energy path as a function of stress and temperature and show that the critical stress vanishes at 700 K, supplying the qualitative elements that explain plastic behavior in the athermal limit. PMID:24033045

Gilbert, M R; Schuck, P; Sadigh, B; Marian, J

2013-08-30

306

On the wave energy potential of Western Black Sea shelf  

E-print Network

In the present study we evaluate the approaches to estimate the wave energy potential of the western Black Sea shelf with numerical models. For the purpose of our evaluation and due to the lack of long time series of measurements in the selected area of the Black Sea, we compare the modeled mean wave power flux output from the SWAN wave model with the only available long term measurements from the buoy of Gelendzhik for the period 1997-2003 (with gaps). The forcing meteorological data for the numerical wave models for the selected years is extracted from the ERA Interim reanalysis of ECMWF (European Centre for Medium range Forecasts). For the year 2003 we also compare the estimated wave power with the modeled by SWAN, using ALADIN regional atmospheric model winds. We try to identify the shortcomings and limitations of the numerical modeling approach to the evaluation of the wave energy potential in Black Sea.

Galabov, Vasko

2013-01-01

307

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

308

A New Model for Calculating the Binding Energy of Lithium Nucleus under the Generalized Yukawa Potential and Hellmann Potential  

E-print Network

In this paper, the Schr\\"odinger equation for 6-body system is studied. We solved this equation for lithium nucleus by using supersymmetry method with the specific potentials. These potentials are Yukawa potential, the generalized Yukawa potential and Hellmann potential. The results of our model for all calculations show that the ground state binding energy of Lithium nucleus with these potentials are very close to the ones obtained in experiments.

Ghazvini, M; Rajabi, A A

2014-01-01

309

Elastic moduli of copper under compression  

SciTech Connect

Starting with a description of the electronic structure of copper, we have studied the zero temperature elastic moduli to 1 Mbar. We have used an empty-core model pseudopotential for the conduction electrons, treated the d-electron interactions in tight binding theory, and calculated the elastic moduli and their volume and pressure derivatives. The results are compared with experiment and with Full Potential Linear Muffin-Tin Orbital (FPLMTO) bandstructure calculations for the elastic moduli and their pressure derivatives.

Straub, G.K.; Wills, J.M.; Wallace, D.C.

1987-01-01

310

Unique potentials for the elastic scattering of 350 MeV ⁷Li from ¹²C and ²⁸Si  

Microsoft Academic Search

Differential cross sections for the elastic scattering of 350 MeV ⁷Li from ¹²C and ²⁸Si have been measured. The characteristics of the angular distributions are very similar to those of 318 MeV ⁶Li scattering from the same targets, with diffractive oscillations at the forward angles and smooth exponential falloff, attributed to the dominance of far-side scattering, at the larger angles.

A. Nadasen; J. Brusoe; J. Farhat; T. Stevens; J. Williams; L. Nieman; J. S. Winfield; R. E. Warner; F. D. Becchetti; J. W. Jaenecke; T. Annakkage; J. Bajema; D. Roberts; H. S. Govinden

1995-01-01

311

Electronic structure, molecular bonding and potential energy surfaces  

SciTech Connect

By virtue of the universal validity of the generalized Born-Oppenheimer separation, potential energy surfaces (PES`) represent the central conceptual as well as quantitative entities of chemical physics and provide the basis for the understanding of most physicochemical phenomena in many diverse fields. The research in this group deals with the elucidation of general properties of PES` as well as with the quantitative determination of PES` for concrete systems, in particular pertaining to reactions involving carbon, oxygen, nitrogen and hydrogen molecules.

Ruedenberg, K. [Ames Laboratory, IA (United States)

1993-12-01

312

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

313

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

314

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

315

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

316

Elastic Scattering of 7Li+27Al at Backward Angles in the 7-11 MeV Energy Range for Application in RBS  

NASA Astrophysics Data System (ADS)

We have measured elastic excitation functions for the 7Li+27Al system, in an energy range close to its Coulomb barrier (Elab = 8.4 MeV) in steps of 0.25 MeV. For this purpose, an array of eight surface-barrier detectors was used. To get an insight on the background composition (mainly ? particles), a telescope-detector was used for atomic-number identification. Identical measurements for the 6Li+27Al system are planned for the near future.

Carnelli, P. F. F.; Abriola, D.; Arazi, A.; Capurro, O. A.; Cardona, M. A.; Fernández Niello, J. O.; Figueira, J. M.; Fimiani, L.; Grinberg, P.; Hojman, D.; Martí, G. V.; Martinez Heimann, D.; Negri, A. E.; Pacheco, A. J.

2010-08-01

317

Elastic Scattering of {sup 7}Li+{sup 27}Al at Backward Angles in the 7-11 MeV Energy Range for Application in RBS  

SciTech Connect

We have measured elastic excitation functions for the {sup 7}Li+{sup 27}Al system, in an energy range close to its Coulomb barrier (E{sub lab} = 8.4 MeV) in steps of 0.25 MeV. For this purpose, an array of eight surface-barrier detectors was used. To get an insight on the background composition (mainly {alpha} particles), a telescope-detector was used for atomic-number identification. Identical measurements for the {sup 6}Li+{sup 27}Al system are planned for the near future.

Carnelli, P. F. F.; Arazi, A.; Cardona, M. A.; Figueira, J. M.; Hojman, D.; Martinez Heimann, D.; Negri, A. E.; Pacheco, A. J. [Laboratorio TANDAR, CNEA, Av. Gral. Paz 1499, B1650KNA, San Martin, Buenos Aires (Argentina); CONICET, Av. Rivadavia 1917, C1033AAJ, Buenos Aires (Argentina); Abriola, D. [IAEA, NAPC-NDS, Vienna International Centre, PO Box 100, Vienna (Austria); Capurro, O. A.; Fimiani, L.; Grinberg, P.; Marti, G. V. [Laboratorio TANDAR, CNEA, Av. Gral. Paz 1499, B1650KNA, San Martin, Buenos Aires (Argentina); Fernandez Niello, J. O. [Laboratorio TANDAR, CNEA, Av. Gral. Paz 1499, B1650KNA, San Martin, Buenos Aires (Argentina); CONICET, Av. Rivadavia 1917, C1033AAJ, Buenos Aires (Argentina); UNSAM, Campus Miguelete, B1650BWA, San Martin, Buenos Aires (Argentina)

2010-08-04

318

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

319

GIS Assessment of Wind Energy Potential in California and Florida  

NASA Astrophysics Data System (ADS)

Energy efficiency coupled with renewable energy technologies can provide most of the U.S. carbon emissions reductions needed to contain atmospheric carbon concentrations at 450-500 parts per million, considered by many to be a tipping point in mitigating climate change. Among the leaders in the alternative energy sector is wind power, which is now one of the largest sources of new power generation in the U.S. creating jobs and revenue for rural communities while powering our economy with an emissions-free source of energy. In 2006, wind turbines capable of generating more than 2,400 megawatts of electricity were installed in the U.S. and by 2007 this number had risen to 3,000 megawatts. The U.S. generated 31 billion kilowatt-hours of wind power in 2007, which is enough electricity to power the equivalent of nearly 3 million average homes. It is estimated that generating the same amount of electricity would require burning 16 million tons of coal or 50 million barrels of oil. This study examines the wind power potential of sites near populated areas in Florida and California to determine the practicability of installing wind turbines at these locations. A GIS was developed in order to conduct a spatial analysis of these sites based on mean annual wind speed measured in meters per second and wind power density ratings measured in watts per square meter. The analysis indicates that coastal areas of Cocoa Beach, Key West, Hollywood, and West Palm Beach, respectively, possess the greatest potential for wind energy in Florida with mean annual wind speeds of 4.9 m/s and average wind power density ratings of 171 w/m2 peaking at Cocoa Beach followed by wind speeds of 4.64 m/s and wind power ratings of 115 w/m2 at Key West. California wind energy potential is even greater than that of Florida with Fairfield exhibiting mean annual wind speeds of 5.9 m/s and average wind power density ratings of 327 w/m2 followed by the Mojave and Palmdale areas with mean annual wind speeds of 5.0 m/s and 4.6 m/s, respectively. Wind power density ratings for Mojave are 240 w/m2 and 153 w/m2 at Palmdale. These results help confirm that wind energy continues to offer a clean, cost-effective, inexhaustible, and readily available means of helping to curb global warming while answering the increasing demand for electricity.

Snow, R. K.; Snow, M. M.

2008-05-01

320

Two-potential approach for electron-molecular collisions at intermediate and high energies - Application to e-N2 scatterings  

NASA Technical Reports Server (NTRS)

A general theoretical approach is proposed for the calculation of elastic, vibrational, and rotational transitions for electron-molecule scattering at intermediate and high-electron-impact energies. In this formulation, contributions to the scattering process come from the incoherent sum of two dominant potentials: a short-range shielded nuclear Coulomb potential from individual atomic centers, and a permanent/induced long-range potential. Application to e-N2 scattering from 50-500 eV incident electron energies has yielded good agreement with absolutely calibrated experiments. Comparisons with other theoretical approaches are made. The physical picture as well as the general features of electron-molecule scattering process are discussed within the framework of the two-potential approach.

Choi, B. H.; Poe, R. T.; Sun, J. C.; Shan, Y.

1979-01-01

321

Chapter 10. Energy This pole vaulter can lift  

E-print Network

at Gravitational Potential Energy · Restoring Forces and Hooke's Law · Elastic Potential Energy · Elastic= + = + = + = + = + = + = + = + #12;Restoring Force: Hooke's Law 16 spF k s= - = - = - = - spring constant Hooke's Law: #12;Restoring Force: Hooke's Law spF k s= - = - = - = - The sign of a restoring force is always opposite to the sign

Dhamala, Mukesh

322

Theoretical studies of potential energy surfaces and computational methods  

SciTech Connect

This project involves the development, implementation, and application of theoretical methods for the calculation and characterization of potential energy surfaces involving molecular species that occur in hydrocarbon combustion. These potential energy surfaces require an accurate and balanced treatment of reactants, intermediates, and products. This difficult challenge is met with general multiconfiguration self-consistent-field (MCSCF) and multireference single- and double-excitation configuration interaction (MRSDCI) methods. In contrast to the more common single-reference electronic structure methods, this approach is capable of describing accurately molecular systems that are highly distorted away from their equilibrium geometries, including reactant, fragment, and transition-state geometries, and of describing regions of the potential surface that are associated with electronic wave functions of widely varying nature. The MCSCF reference wave functions are designed to be sufficiently flexible to describe qualitatively the changes in the electronic structure over the broad range of geometries of interest. The necessary mixing of ionic, covalent, and Rydberg contributions, along with the appropriate treatment of the different electron-spin components (e.g. closed shell, high-spin open-shell, low-spin open shell, radical, diradical, etc.) of the wave functions, are treated correctly at this level. Further treatment of electron correlation effects is included using large scale multireference CI wave functions, particularly including the single and double excitations relative to the MCSCF reference space. This leads to the most flexible and accurate large-scale MRSDCI wave functions that have been used to date in global PES studies.

Shepard, R. [Argonne National Laboratory, IL (United States)

1993-12-01

323

Potential environmental effects of energy conservation measures in northwest industries  

SciTech Connect

The Bonneville Power Administration (Bonneville) has identified 101 plants in the Pacific Northwest that account for 80% of the region's industrial electricity consumption. These plants offer a precise target for a conservation program. PNL determined that most of these 101 plants were represented by 11 major industries. We then reviewed 36 major conservation technologies used in these 11 industrial settings to determine their potential environmental impacts. Energy efficiency technologies designed for industrial use may result in direct or indirect environmental impacts. Effects may result from the production of the conservation measure technology, changes in the working environment due to different energy and material requirements, or changes to waste streams. Industry type, work-place conditions, worker training, and environmental conditions inside and outside the plant are all key variables that may affect environmental outcomes. To address these issues this report has three objectives: Describe potential conservation measures that Bonneville may employ in industrial programs and discuss potential primary impacts. Characterize industrial systems and processes where the measure may be employed and describe general environmental issues associated with each industry type. Review environmental permitting, licensing, and other regulatory actions required for industries and summarize the type of information available from these sources for further analysis.

Baechler, M C; Gygi, K F; Hendrickson, P L

1992-01-01

324

Intermolecular potential energy surface and thermophysical properties of ethylene oxide.  

PubMed

A six-dimensional potential energy hypersurface (PES) for two interacting rigid ethylene oxide (C2H4O) molecules was determined from high-level quantum-chemical ab initio calculations. The counterpoise-corrected supermolecular approach at the MP2 and CCSD(T) levels of theory was utilized to determine interaction energies for 10178 configurations of two molecules. An analytical site-site potential function with 19 sites per ethylene oxide molecule was fitted to the interaction energies and fine tuned to agree with data for the second acoustic virial coefficient from accurate speed of sound measurements. The PES was validated by computing the second virial coefficient, shear viscosity, and thermal conductivity. The values of these properties are substantiated by the best experimental data as they tend to fall within the uncertainty intervals and also obey the experimental temperature functions, except for viscosity, where experimental data are insufficient. Due to the lack of reliable data, especially for the transport properties, our calculated values are currently the most accurate estimates for these properties of ethylene oxide. PMID:25362314

Crusius, Johann-Philipp; Hellmann, Robert; Hassel, Egon; Bich, Eckard

2014-10-28

325

Intermolecular potential energy surface and thermophysical properties of ethylene oxide  

NASA Astrophysics Data System (ADS)

A six-dimensional potential energy hypersurface (PES) for two interacting rigid ethylene oxide (C2H4O) molecules was determined from high-level quantum-chemical ab initio calculations. The counterpoise-corrected supermolecular approach at the MP2 and CCSD(T) levels of theory was utilized to determine interaction energies for 10178 configurations of two molecules. An analytical site-site potential function with 19 sites per ethylene oxide molecule was fitted to the interaction energies and fine tuned to agree with data for the second acoustic virial coefficient from accurate speed of sound measurements. The PES was validated by computing the second virial coefficient, shear viscosity, and thermal conductivity. The values of these properties are substantiated by the best experimental data as they tend to fall within the uncertainty intervals and also obey the experimental temperature functions, except for viscosity, where experimental data are insufficient. Due to the lack of reliable data, especially for the transport properties, our calculated values are currently the most accurate estimates for these properties of ethylene oxide.

Crusius, Johann-Philipp; Hellmann, Robert; Hassel, Egon; Bich, Eckard

2014-10-01

326

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

327

Exploring the local elastic properties of bilayer membranes using molecular dynamics simulations.  

PubMed

Membrane mechanical elastic properties regulate a variety of cellular processes involving local membrane deformation, such as ion channel function and vesicle fusion. In this work, we used molecular dynamics simulations to estimate the local elastic properties of a membrane. For this, we calculated the energy needed to extract a DOPE lipid molecule, modified with a linker chain, from a POPC bilayer membrane using the umbrella sampling technique. Although the extraction energy entails several contributions related not only to elastic deformation but also to solvation, careful analysis of the potential of mean force (PMF) allowed us to dissect the elastic contribution. With this information, we calculated an effective linear spring constant of 44 ± 4 kJ·nm(-2)·mol(-1) for the DOPC membrane, in agreement with experimental estimates. The membrane deformation profile was determined independently during the stretching process in molecular detail, allowing us to fit this profile to a previously proposed continuum elastic model. Through this approach, we calculated an effective membrane spring constant of 42 kJ·nm(-2)·mol(-1), which is in good agreement with the PMF calculation. Furthermore, the solvation energy we derived from the data is shown to match the solvation energy estimated from critical micelle formation constants. This methodology can be used to determine how changes in lipid composition or the presence of membrane modifiers can affect the elastic properties of a membrane at a local level. PMID:25325715

Pieffet, Gilles; Botero, Alonso; Peters, Günther H; Forero-Shelton, Manu; Leidy, Chad

2014-11-13

328

Elastic properties of spherically anisotropic piezoelectric composites  

NASA Astrophysics Data System (ADS)

Effective elastic properties of spherically anisotropic piezoelectric composites, whose spherically anisotropic piezoelectric inclusions are embedded in an infinite non-piezoelectric matrix, are theoretically investigated. Analytical solutions for the elastic displacements and the electric potentials under a uniform external strain are derived exactly. Taking into account of the coupling effects of elasticity, permittivity and piezoelectricity, the formula is derived for estimating the effective elastic properties based on the average field theory in the dilute limit. An elastic response mechanism is revealed, in which the effective elastic properties increase as inclusion piezoelectric properties increase and inclusion dielectric properties decrease. Moreover, a piezoelectric response mechanism, of which the effective piezoelectric response vanishes due to the symmetry of spherically anisotropic composite, is also disclosed.

Wei, En-Bo; Gu, Guo-Qing; Poon, Ying-Ming

2010-09-01

329

Assessing geothermal energy potential in upstate New York. Final report  

SciTech Connect

The potential of geothermal energy for future electric power generation in New York State is evaluated using estimates of temperatures of geothermal reservoir rocks. Bottom hole temperatures from over 2000 oil and gas wells in the region were integrated into subsurface maps of the temperatures for specific geothermal reservoirs. The Theresa/Potsdam formation provides the best potential for extraction of high volumes of geothermal fluids. The evaluation of the Theresa/Potsdam geothermal reservoir in upstate New York suggests that an area 30 miles east of Elmira, New York has the highest temperatures in the reservoir rock. The Theresa/Potsdam reservoir rock should have temperatures about 136 {degrees}C and may have as much as 450 feet of porosity in excess of 8%. Estimates of the volumes of geothermal fluids that can be extracted are provided and environmental considerations for production from a geothermal well is discussed.

Hodge, D.S. [SUNY, Buffalo, NY (United States)

1996-08-01

330

Potential energy surfaces and reaction dynamics of polyatomic molecules  

SciTech Connect

A simple empirical valence bond (EVB) model approach is suggested for constructing global potential energy surfaces for reactions of polyatomic molecular systems. This approach produces smooth and continuous potential surfaces which can be directly utilized in a dynamical study. Two types of reactions are of special interest, the unimolecular dissociation and the unimolecular isomerization. For the first type, the molecular dissociation dynamics of formaldehyde on the ground electronic surface is investigated through classical trajectory calculations on EVB surfaces. The product state distributions and vector correlations obtained from this study suggest very similar behaviors seen in the experiments. The intramolecular hydrogen atom transfer in the formic acid dimer is an example of the isomerization reaction. High level ab initio quantum chemistry calculations are performed to obtain optimized equilibrium and transition state dimer geometries and also the harmonic frequencies.

Chang, Yan-Tyng.

1991-11-01

331

The Nonlinear Spring and Energy Conservation.  

ERIC Educational Resources Information Center

Describes an air track experiment demonstrating the transfer of mechanical energy from elastic potential to kinetic. Discusses four methods for calculating energy stored in the spring. Included are pictures, typical data, and graphs. (YP)

Sherfinski, John

1989-01-01

332

Potential energy surfaces and quantum yields for photochromic diarylethene reactions.  

PubMed

Photochromic diarylethenes (DAEs) are among the most promising molecular switching systems for future molecular electronics. Numerous derivatives have been synthesized recently, and experimental quantum yields (QYs) have been reported for two categories of them. Although the QY is one of the most important properties in various applications, it is also the most difficult property to predict before a molecule is actually synthesized. We have previously reported preliminary theoretical studies on what determines the QYs in both categories of DAE derivatives. Here, reflecting theoretical analyses of potential energy surfaces and recent experimental results, a rational explanation of the general guiding principle for QY design is presented for future molecular design. PMID:23644976

Nakamura, Shinichiro; Uchida, Kingo; Hatakeyama, Makoto

2013-01-01

333

Context Rich Problems Online Archives: Electric Potential Energy Problems  

NSDL National Science Digital Library

This page provides a set of context-rich physics problems relating to electric potential energy. Each context-rich problem is based on a real-world situation, and includes both information that is relevant to solving the problem and extraneous information. Strategies for problem solving are not explicitly provided. Each problem is formulated so it is too difficult for one student to solve alone, yet not too difficult for a group to master. This resource is based on the research results of the Minnesota Physics Education Research group. See Related items on this page for a link to the full collection.

Group, University O.; Heller, Kenneth; Heller, Patricia

2008-09-29

334

Toward an improved ground state potential energy surface of ozone.  

PubMed

A systematic study of the ozone potential energy surface was performed by means of high level ab initio techniques. The methods include icMR-CISD and icMR-AQCC with all electrons correlated using a full valence CAS reference space and basis sets up to sextuple-? quality along with extrapolation to the complete basis set limit. We computed a dense 3D grid as well as 1D cuts along stretching and bending coordinates around the open (C(2v)) equilibrium structure as well as along the minimum energy path to dissociation including the transition state and the van der Waals minimum region. The detailed analysis of our results confirms earlier calculations by the Schinke group and assures that these are not biased by deficiencies of the basis set, lack of relativistic corrections, or core correlation effects. Finally, we discuss possible sources of error that may explain the remaining discrepancies compared to experimental findings. PMID:20825243

Holka, Filip; Szalay, Péter G; Müller, Thomas; Tyuterev, Vladimir G

2010-09-16

335

Higher Order Elastic Constants, Gruneisen Parameters and Lattice Thermal Expansion of Lithium Niobate  

Microsoft Academic Search

The second and third-order elastic constants and pressure derivatives of second- order elastic constants of trigonal LiNbO3 (lithium niobate) have been obtained using the deformation theory. The strain energy density estimated using finite strain elasticity is compared with the strain dependent lattice energy density obtained from the elastic continuum model approximation. The second-order elastic constants and the non-vanishing third-order elastic

THRESIAMMA PHILIP; C. S. MENON; K. INDULEKHA

2006-01-01

336

Vibration of an elastic tensegrity structure  

Microsoft Academic Search

The dynamic behavior of a simple elastic tensegrity structure is examined, in order to validate observations that the natural damping of the elastic elements in such a structure is poorly mobilized, due to the natural flexibility of the equilibrium position of the structure. It is confirmed, analytically and numerically, that the energy decay of such a system is slower than

Irving J Oppenheim; William O Williams

2001-01-01

337

An ab initio potential energy surface and vibrational energy levels of HXeO  

NASA Astrophysics Data System (ADS)

The potential energy surfaces for the electronic ground state of the HXeO molecule is constructed from more than 3500 ab initio points at the internally contracted multi-reference configuration interaction with the Davidson correction (icMRCI + Q) level employing large basis sets. The stabilities and dissociation barriers are identified from the potential energy surfaces. The three-body dissociation channel is found to be the dominate dissociation channel for HXeO. Low-lying vibrational energy levels of both HXeO and DXeO are calculated on the three-dimensional potential energy surface using the Lanczos algorithm, and found to be in good agreement with known experimental band origins.

Huang, Zhengguo

2009-05-01

338

An Ab Initio Based Potential Energy Surface for Water  

NASA Technical Reports Server (NTRS)

We report a new determination of the water potential energy surface. A high quality ab initio potential energy surface (PES) and dipole moment function of water have been computed. This PES is empirically adjusted to improve the agreement between the computed line positions and those from the HITRAN 92 data base. The adjustment is small, nonetheless including an estimate of core (oxygen 1s) electron correlation greatly improves the agreement with experiment. Of the 27,245 assigned transitions in the HITRAN 92 data base for H2(O-16), the overall root mean square (rms) deviation between the computed and observed line positions is 0.125/cm. However the deviations do not correspond to a normal distribution: 69% of the lines have errors less than 0.05/cm. Overall, the agreement between the line intensities computed in the present work and those contained in the data base is quite good, however there are a significant number of line strengths which differ greatly.

Partridge, Harry; Schwenke, David W.; Langhoff, Stephen R. (Technical Monitor)

1996-01-01

339

Proton-proton elastic scattering at the LHC energy of \\chem{\\sqrt{s} = 7\\,TeV}  

NASA Astrophysics Data System (ADS)

Proton-proton elastic scattering has been measured by the TOTEM experiment at the CERN Large Hadron Collider at \\sqrt{s} = 7\\,TeV in dedicated runs with the Roman Pot detectors placed as close as seven times the transverse beam size (?beam) from the outgoing beams. After careful study of the accelerator optics and the detector alignment, |t|, the square of four-momentum transferred in the elastic scattering process, has been determined with an uncertainty of \\delta t = 0.1\\,\\rm{GeV} \\sqrt{\\vert t\\vert } . In this letter, first results of the differential cross-section are presented covering a |t|-range from 0.36 to 2.5 GeV2. The differential cross-section in the range 0.36 < |t| < 0.47 GeV2 is described by an exponential with a slope parameter B = (23.6 ± 0.5stat ± 0.4syst) GeV-2, followed by a significant diffractive minimum at |t| = (0.53 ± 0.01stat ± 0.01syst) GeV2. For |t|-values larger than ~1.5 GeV2, the cross-section exhibits a power law behaviour with an exponent of -7.8 ± 0.3stat ± 0.1syst. When compared to predictions based on the different available models, the data show a strong discriminative power despite the small t-range covered.

TOTEM Collaboration; Antchev, G.; Aspell, P.; Atanassov, I.; Avati, V.; Baechler, J.; Berardi, V.; Berretti, M.; Bozzo, M.; Brücken, E.; Buzzo, A.; Cafagna, F. S.; Calicchio, M.; Catanesi, M. G.; Covault, C.; Csanád, M.; Csörgö, T.; Deile, M.; Dimovasili, E.; Doubek, M.; Eggert, K.; Eremin, V.; Ferro, F.; Fiergolski, A.; Garcia, F.; Giani, S.; Greco, V.; Grzanka, L.; Heino, J.; Hilden, T.; Janda, M.; Kašpar, J.; Kopal, J.; Kundrát, V.; Kurvinen, K.; Lami, S.; Latino, G.; Lauhakangas, R.; Leszko, T.; Lippmaa, E.; Lokají?ek, M.; Lo Vetere, M.; Rodríguez, F. Lucas; Macrí, M.; Magaletti, L.; Magazzù, G.; Mercadante, A.; Minutoli, S.; Nemes, F.; Niewiadomski, H.; Noschis, E.; Novák, T.; Oliveri, E.; Oljemark, F.; Orava, R.; Oriunno, M.; Österberg, K.; Perrot, A.-L.; Palazzi, P.; Pedreschi, E.; Petäjäjärvi, J.; Procházka, J.; Quinto, M.; Radermacher, E.; Radicioni, E.; Ravotti, F.; Robutti, E.; Ropelewski, L.; Ruggiero, G.; Saarikko, H.; Santroni, A.; Scribano, A.; Sette, G.; Snoeys, W.; Spinella, F.; Sziklai, J.; Taylor, C.; Turini, N.; Vacek, V.; Vitek, M.; Welti, J.; Whitmore, J.

2011-08-01

340

Electric Energy Conservation and Production Project: Vpolume 3: Wind energy potential  

SciTech Connect

A final report has been prepared under the Electric Energy Conservation and Production Project, conducted by the Blackfeet Indian Tribe and its consultants, Black Hawk Associates, Inc. The report addresses two major issues - the heavy reliance on electricity by residents of the Blackfeet Reservation, and the opportunities for electricity production from wind energy resources on the Reservation. The findings of this report (1) help provide a basis for comprehensive energy management planning on the Reservation, (2) analyze the potential for minimizing electricity demand and maximizing the efficiency of electrical end-uses through appropriate conservation measures, (3) assess the potential of wind energy resources located on the Reservation, and (4) identify and assess the technical, financial, legal, institutional, and regulatory issues involved in wind energy development within the Blackfeet Reservation.

Not Available

1984-02-01

341

Potential contribution of wind energy to climate change mitigation  

NASA Astrophysics Data System (ADS)

It is still possible to limit greenhouse gas emissions to avoid the 2 °C warming threshold for dangerous climate change. Here we explore the potential role of expanded wind energy deployment in climate change mitigation efforts. At present, most turbines are located in extra-tropical Asia, Europe and North America, where climate projections indicate continuity of the abundant wind resource during this century. Scenarios from international agencies indicate that this virtually carbon-free source could supply 10-31% of electricity worldwide by 2050 (refs , ). Using these projections within Intergovernmental Panel on Climate Change Representative Concentration Pathway (RCP) climate forcing scenarios, we show that dependent on the precise RCP followed, pursuing a moderate wind energy deployment plan by 2050 delays crossing the 2 °C warming threshold by 1-6 years. Using more aggressive wind turbine deployment strategies delays 2 °C warming by 3-10 years, or in the case of RCP4.5 avoids passing this threshold altogether. To maximize these climate benefits, deployment of non-fossil electricity generation must be coupled with reduced energy use.

Barthelmie, R. J.; Pryor, S. C.

2014-08-01

342

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 equation agrees with the usual expression for the energy of a radial density distribution. The second degree terms give a maximum nonhydrostatic energy in the mantle and crust of -2.77 x 10 to the twenty-ninth power ergs, an order of magnitude. 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 twentieth power poises is found by assuming the total geothermal flux is due to viscous dissipation. If the nonequilibrium figure is dynamically maintained by the earth acting as a heat engine at one per cent efficiency, then the viscosity is ten to the twenty second power poises, a number preferred by some as the viscosity of the mantle.

Rubincam, D. P.

1977-01-01

343

Steam systems in industry: Energy use and energy efficiency improvement potentials  

SciTech Connect

Steam systems are a part of almost every major industrial process today. Thirty-seven percent of the fossil fuel burned in US industry is burned to produce steam. In this paper we will establish baseline energy consumption for steam systems. Based on a detailed analysis of boiler energy use we estimate current energy use in boilers in U.S. industry at 6.1 Quads (6.4 EJ), emitting almost 66 MtC in CO{sub 2} emissions. We will discuss fuels used and boiler size distribution. We also describe potential savings measures, and estimate the economic energy savings potential in U.S. industry (i.e. having payback period of 3 years or less). We estimate the nationwide economic potential, based on the evaluation of 16 individual measures in steam generation and distribution. The analysis excludes the efficient use of steam and increased heat recovery. Based on the analysis we estimate the economic potential at 18-20% of total boiler energy use, resulting in energy savings approximately 1120-1190 TBtu ( 1180-1260 PJ). This results in a reduction of CO{sub 2} emissions equivalent to 12-13 MtC.

Einstein, Dan; Worrell, Ernst; Khrushch, Marta

2001-07-22

344

Alpha-deuteron (triton) analysis of 6(7)Li elastic scattering  

NASA Astrophysics Data System (ADS)

The elastic scattering of 6,7Li+28Si reactions has been analyzed in the framework of the double folding optical model. Semi-microscopic folded potentials are generated based on the alpha (?)-cluster structure of the colliding nuclei. Successful reproduction of the observed angular distributions of the elastic scattering differential cross section and reaction cross sections has been obtained at different energies using the derived potentials. A microscopic folding approach based on the effective DDM3Y nucleon-nucleon interaction and the nuclear matter densities of the interacting nuclei is also considered.

El-Azab Farid, M.; Ibraheem, Awad A.; Al-Zahrani, J. H.; Al-Harbi, W. R.; Hassanain, M. A.

2013-07-01

345

Mechanics of Elastic Solids  

NSDL National Science Digital Library

After conducting the associated activity, students are introduced to the material behavior of elastic solids. Engineering stress and strain are defined and their importance in designing devices and systems is explained. How engineers measure, calculate and interpret properties of elastic materials is addressed. Students calculate stress, strain and modulus of elasticity, and learn about the typical engineering stress-strain diagram (graph) of an elastic material.

Integrated Teaching And Learning Program

346

Extremely fast prey capture in pipefish is powered by elastic recoil  

Microsoft Academic Search

The exceptionally high speed at which syngnathid fishes are able to rotate their snout towards prey and capture it by suction is potentially caused by a catapult mechanism in which the energy previously stored in deformed elastic elements is suddenly released. According to this hypothesis, tension is built up in tendons of the post-cranial muscles before prey capture is initiated.

Sam Van Wassenbergh; James A. Strother; Brooke E. Flammang; Lara A. Ferry-Graham; Peter Aerts

2008-01-01

347

Microscopic optical model potentials for p-nucleus scattering at intermediate energies  

SciTech Connect

A comparative study of the microscopic optical potentials viz., semimicroscopic with extended Jeukenne-Lejeune-Mahaux interaction and microscopic Brueckner theory using Hamada-Johnston as well as Urbana V14 soft-core internucleon interactions, has been carried out. These microscopic optical potentials are compared with that of Dirac phenomenology (DP) for the polarized proton-{sup 40}Ca elastic scattering at 35 MeV and 200 MeV. These potentials have different shapes for 200 MeV below 4 fm. In particular, for the real part of the central potential, only the Dirac phenomenology and the microscopic optical potential calculated with the Hamada-Johnston interaction exhibit the well known wine-bottle-bottom shape. It is found that the calculated observables (cross section, analyzing power and spin rotation function) using these potentials having different shapes, compare well with the experiment.

Hemalatha, M. [Department of Physics, I.I.T.-Powai, Mumbai 400076 (India); Gambhir, Y. K. [Department of Physics, I.I.T.-Powai, Mumbai 400076 (India); Manipal Academy of Higher Education, Manipal 576119 (India); Kailas, S. [Nuclear Physics Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Haider, W. [Department of Physics, Aligarh Muslim University, Aligarh 202002 (India)

2007-03-15

348

French Brittany macroalgae screening: composition and methane potential for potential alternative sources of energy and products.  

PubMed

Macroalgae are biomass resources that represent a valuable feedstock to be used entirely for human consumption or for food additives after some extractions (mainly colloids) and/or for energy production. In order to better develop the algal sector, it is important to determine the capacity of macroalgae to produce these added-values molecules for food and/or for energy industries on the basis of their biochemical characteristics. In this study, ten macroalgae obtained from French Brittany coasts (France) were selected. The global biochemical composition (proteins, lipids, carbohydrates, fibers), the presence and characteristics of added-values molecules (alginates, polyphenols) and the biochemical methane potential of these algae were determined. Regarding its biochemical composition, Palmaria palmata is interesting for food (rich in nutrients) and for anaerobic digestion (0.279 LCH4/gVS). Saccharina latissima could be used for alginate extraction (242 g/kgTS, ratio between mannuronic and guluronic acid M/G=1.4) and Sargassum muticum for polyphenol extraction (19.8 g/kgTS). PMID:23896436

Jard, G; Marfaing, H; Carrère, H; Delgenes, J P; Steyer, J P; Dumas, C

2013-09-01

349

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

PubMed

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) were evaluated. The input energy steps for the energy life cycle assessment (ELCA) include collection, generator, torrefaction, crushing, briquetting, transportation, energy production, condensation, air pollution control and distribution of biofuels to the point of end use. Every PGT has a positive energy benefit. The input of energy required for the transportation and pre-treatment are major steps in the ELCA. On-site briquetting of refused-derived fuel (RDF) provides an alternative means of reducing transportation energy requirements. Bio-energy sources, such as waste rice straw, provide an ideal material for the bio-fuel plant. PMID:21507625

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

2011-06-01

350

Disagreement between capture probabilities extracted from capture and quasi-elastic backscattering excitation functions  

E-print Network

Experimental quasi-elastic backscattering and capture (fusion) excitation functions are usually used to extract the s-wave capture probabilities for the heavy-ion reactions. We investigated the $^{16}$O+$^{120}$Sn,$^{144}$Sm,$^{208}$Pb systems at energies near and below the corresponding Coulomb barriers and concluded that the probabilities extracted from quasi-elastic data are much larger than the ones extracted from fusion excitation functions at sub and deep-sub barrier energies. This seems to be a reasonable explanation for the known disagreement observed in literature for the nuclear potential diffuseness derived from both methods.

V. V. Sargsyan; G. G. Adamian; N. V. Antonenko; R. P. S. Gomes

2014-06-05

351

How does the potential energy of a rising helium-filled balloon change?  

Microsoft Academic Search

I discuss why the buoyant force as given by Archimedes' principle is a conservative force with an associated potential energy. I then provide several arguments why a rising helium balloon loses potential energy.

David Keeports

2002-01-01

352

How does the potential energy of a rising helium-filled balloon change?  

NASA Astrophysics Data System (ADS)

I discuss why the buoyant force as given by Archimedes' principle is a conservative force with an associated potential energy. I then provide several arguments why a rising helium balloon loses potential energy.

Keeports, David

2002-03-01

353

Potential alternative energy technologies on the Outer Continental Shelf.  

SciTech Connect

This technical memorandum (TM) describes the technology requirements for three alternative energy technologies for which pilot and/or commercial projects on the U.S. Outer Continental Shelf (OCS) are likely to be proposed within the next five to seven years. For each of the alternative technologies--wind, wave, and ocean current--the TM first presents an overview. After each technology-specific overview, it describes the technology requirements for four development phases: site monitoring and testing, construction, operation, and decommissioning. For each phase, the report covers the following topics (where data are available): facility description, electricity generated, ocean area (surface and bottom) occupied, resource requirements, emissions and noise sources, hazardous materials stored or used, transportation requirements, and accident potential. Where appropriate, the TM distinguishes between pilot-scale (or demonstration-scale) facilities and commercial-scale facilities.

Elcock, D.; Environmental Assessment

2007-04-20

354

Osmosis, colligative properties, entropy, free energy and the chemical potential  

E-print Network

A diffusive model of osmosis is presented that explains currently available experimental data. It makes predictions that distinguish it from the traditional convective flow model of osmosis, some of which have already been confirmed experimentally and others have yet to be tested. It also provides a simple kinetic explanation of Raoult's law and the colligative properties of dilute aqueous solutions. The diffusive model explains that when a water molecule jumps from low to high osmolarity at equilibrium, the free energy change is zero because the work done pressurizing the water molecule is balanced by the entropy of mixing. It also explains that equal chemical potentials are required for particle exchange equilibrium in analogy with the familiar requirement of equal temperatures at thermal equilibrium.

Peter Hugo Nelson

2014-09-13

355

Nuclear rainbow in elastic scattering of {sup 9}Be nuclei  

SciTech Connect

A systematic investigation of the elastic scattering of the {sup 9}Be nucleus, which is among themost loosely bound stable nuclei was performed.Differential cross sections for elastic {sup 9}Be + {sup 16}O scattering were measured at a c.m. energy of 47.5 MeV (beam of 132-MeV {sup 16}O nuclei). Available data at different energy values and data for neighboring nuclei were included in our analysis. As a result, the very fact of rainbow scattering was reliably established for the first time in systems involving {sup 9}Be. In addition, the analysis in question made it possible to identify Airy minima and to determine unambiguously the nucleus-nucleus potential with a high probability.

Glukhov, Yu. A., E-mail: gloukhov@inbox.ru; Ogloblin, A. A.; Artemov, K. P.; Rudakov, V. P. [Russian Research Center Kurchatov Institute (Russian Federation)

2010-01-15

356

On gradient field theories: gradient magnetostatics and gradient elasticity  

E-print Network

In this work the fundamentals of gradient field theories are presented and reviewed. In particular, the theories of gradient magnetostatics and gradient elasticity are investigated and compared. For gradient magnetostatics, non-singular expressions for the magnetic vector gauge potential, the Biot-Savart law, the Lorentz force and the mutual interaction energy of two electric current loops are derived and discussed. For gradient elasticity, non-singular forms of all dislocation key-formulas (Burgers equation, Mura equation, Peach-Koehler stress equation, Peach-Koehler force equation, and mutual interaction energy of two dislocation loops) are presented. In addition, similarities between an electric current loop and a dislocation loop are pointed out. The obtained fields for both gradient theories are non-singular due to a straightforward and self-consistent regularization.

Lazar, Markus

2014-01-01

357

Relation between quark-antiquark potential and quark-antiquark free energy in hadronic matter  

E-print Network

We study the relation between the quark-antiquark potential and the quark-antiquark free energy in hadronic matter. While a temperature is over the critical temperature, the potential of a heavy quark and a heavy antiquark almost equals the free energy, otherwise the quark-antiquark potential is substantially larger than the quark-antiquark free energy. While a temperature is below the critical temperature, the quark-antiquark free energy can be taken as the quark-antiquark potential.

Zhen-Yu Shen; Xiao-Ming Xu

2014-06-19

358

Theoretical study of the effect of point defects on the elastic constants of copper  

NASA Astrophysics Data System (ADS)

Using the recently published semi-empirical potential of Ackland, Tichy, Vitek and Finnis [1] for copper, and a standard Morse potential, the change in elastic constants due to the introduction of self-interstitial atoms (SIAs) and vacancies into a perfect lattice is investigated. Elastic energy is calculated for various strained states, using the technique of quenched molecular dynamics. The relaxed configuration of these strained states is thus found and the elastic constants are calculated from the energies of these strained states. Constant pressure molecular dynamics is used to find the fully relaxed position of the <100> SIA and that of the vacancy in an unstrained case. From this unstrained configuration the dipole tensor (P ij) is calculated, and from the change in elastic moduli the polarisabilities (? ijkl) are calculated. The dipole tensor is found to be qualitatively similar with both potentials, but differences in sign are found in the polarisabilities. Isolated interstitials are found to to increase all the elastic moduli, contrary to previous calculations, whereas their mutual interaction tends to reduce the moduli. In conjunction with experimental data, this work provides evidence for the formation of clusters of interstitials, and suggests that the SIPA model of irradiation creep [2] is not applicable to copper.

Ackland, G. J.

1988-03-01

359

Potential for supplying solar thermal energy to industrial unit operations  

SciTech Connect

Previous studies have identified major industries deemed most appropriate for the near-term adoption of solar thermal technology to provide process heat; these studies have been based on surveys that followed standard industrial classifications. This paper presents an alternate, perhaps simpler analysis of this potential, considered in terms of the end-use of energy delivered to industrial unit operations. For example, materials, such as animal feed, can be air dried at much lower temperatures than are currently used. This situation is likely to continue while economic supplies of natural gas are readily available. However, restriction of these supplies could lead to the use of low-temperature processes, which are more easily integrated with solar thermal technology. The adoption of solar technology is also favored by other changes, such as the relative rates of increase of the costs of electricity and natural gas, and by energy conservation measures. Thus, the use of low-pressure steam to provide process heat could be replaced economically with high-temperature hot water systems, which are more compatible with solar technology. On the other hand, for certain operations such as high-temperature catalytic and distillation processes employed in petroleum refining, there is no ready alternative to presently employed fluid fuels.

May, E.K.

1980-04-01

360

On the potential of a new IVUS elasticity modulus imaging approach for detecting vulnerable atherosclerotic coronary plaques: in vitro vessel phantom study  

NASA Astrophysics Data System (ADS)

Peak cap stress amplitude is recognized as a good indicator of vulnerable plaque (VP) rupture. However, such stress evaluation strongly relies on a precise, but still lacking, knowledge of the mechanical properties exhibited by the plaque components. As a first response to this limitation, our group recently developed, in a previous theoretical study, an original approach, called iMOD (imaging modulography), which reconstructs elasticity maps (or modulograms) of atheroma plaques from the estimation of strain fields. In the present in vitro experimental study, conducted on polyvinyl alcohol cryogel arterial phantoms, we investigate the benefit of coupling the iMOD procedure with the acquisition of intravascular ultrasound (IVUS) measurements for detection of VP. Our results show that the combined iMOD-IVUS strategy: (1) successfully detected and quantified soft inclusion contours with high positive predictive and sensitivity values of 89.7 ± 3.9% and 81.5 ± 8.8%, respectively, (2) estimated reasonably cap thicknesses larger than ~300 µm, but underestimated thinner caps, and (3) quantified satisfactorily Young's modulus of hard medium (mean value of 109.7 ± 23.7 kPa instead of 145.4 ± 31.8 kPa), but overestimated the stiffness of soft inclusions (mean Young`s moduli of 31.4 ± 9.7 kPa instead of 17.6 ± 3.4 kPa). All together, these results demonstrate a promising benefit of the new iMOD-IVUS clinical imaging method for in vivo VP detection.

Le Floc'h, Simon; Cloutier, Guy; Finet, Gérard; Tracqui, Philippe; Pettigrew, Roderic I.; Ohayon, Jacques

2010-10-01

361

Energy Policy 32 (2004) 289297 The potential of solar electric power for meeting future US energy  

E-print Network

forecasting; Energy futures analysis; PV-ANWR comparison Direct comparison of Arctic National Wildlife Refuge (ANWR) oil production and potential photovoltaics (PV) output (during the 70-year expected pumping lifetime of the ANWR deposit) has been neglected in the recent US policy debate. In part, this is because

Delaware, University of

362

Wind and Solar Energy Potential Assessment for Development of Renewables Energies Applications in Bucaramanga, Colombia  

NASA Astrophysics Data System (ADS)

Currently, the trend of micro-grids and small-scale renewable generation systems implementation in urban environments requires to have historical and detailed information about the energy potential resource in site. In Colombia, this information is limited and do not favor the design of these applications; for this reason, must be made detailed studies of the energy potential in their cities. In this paper is presented the wind and solar energy resource assessment for the city of Bucaramanga, based on the monitoring on four strategic points during the years 2010, 2011 and 2012. According to the analysis, is evidenced a significant solar resource throughout the year ascending on average to 1 734 kWh/m2, equivalent to 4.8 kWh/m2/day. Also, from a wind statistical study based on the Weibull probability distribution and Wind Power Density (WPD) was established the wind potential as Class 1 according to the scale of the Department of Energy of the United States (DOE), since the average speed is near 1.4 m/s. Due this, it is technically unfeasible the using of micro-turbines in the city, even so their potential for natural ventilation of building was analyzed. Finally, is presented a methodology to analyze solar harvesting by sectors in the city, according to the solar motion and shadowing caused by existing structures.

Ordóñez, G.; Osma, G.; Vergara, P.; Rey, J.

2014-06-01

363

Footprinting molecular electrostatic potential surfaces for calculation of solvation energies.  

PubMed

A liquid is composed of an ensemble of molecules that populate a large number of different states, so calculation of the solvation energy of a molecule in solution requires a method for summing the interactions with the environment over all of these states. The surface site interaction model for the properties of liquids at equilibrium (SSIMPLE) simplifies the surface of a molecule to a discrete number of specific interaction sites (SSIPs). The thermodynamic properties of these interaction sites can be characterised experimentally, for example, through measurement of association constants for the formation of simple complexes that feature a single H-bonding interaction. Correlation of experimentally determined solution phase H-bond parameters with gas phase ab initio calculations of maxima and minima on molecular electrostatic potential surfaces (MEPS) provides a method for converting gas phase calculations on isolated molecules to parameters that can be used to estimate solution phase interaction free energies. This approach has been generalised using a footprinting technique that converts an MEPS into a discrete set of SSIPs (each described by a polar interaction parameter, ?i). These SSIPs represent the molecular recognition properties of the entire surface of the molecule. For example, water is described by four SSIPs, two H-bond donor sites and two H-bond acceptor sites. A liquid mixture is described as an ensemble of SSIPs that represent the components of the mixture at appropriate concentrations. Individual SSIPs are assumed to be independent, so speciation of SSIP contacts can be calculated based on properties of the individual SSIP interactions, which are given by the sum of a polar (?i?j) and a non-polar (E(vdW)) interaction term. Results are presented for calculation the free energies of transfer of a range of organic molecules from the pure liquid into water, from the pure liquid into n-hexadecane, from n-hexadecane into water, from n-octanol into water, and for the transfer of water from pure water into a range of organic liquids. The agreement with experiment is accurate to within 1.6-3.9 kJ mol(-1) root mean square difference, which suggests that the SSIMPLE approach is a promising method for estimation of solvation energies in more complex systems. PMID:24064723

Calero, Christian Solis; Farwer, Jochen; Gardiner, Eleanor J; Hunter, Christopher A; Mackey, Mark; Scuderi, Serena; Thompson, Stuart; Vinter, Jeremy G

2013-11-01

364

Folding Model Analysis of 6He + 12C Elastic Scattering  

NASA Astrophysics Data System (ADS)

Elastic scattering of the two-neutron halo nucleus, 6He, on 12C target at 38.3 and 41.6 MeV/nucleon has been analyzed in the framework of the double-folding optical model. Real double-folded potentials based on the realistic density-dependent DDM3Y and JLM effective nucleon-nucleon interactions are generated using different forms of the nuclear matter density distribution of 6He. The imaginary optical potentials are taken in the conventional Woods-Saxon form. The bare (unnormalized) real folded potentials derived from the JLM interaction are more successful in reproducing the data at both energies than those derived from the DDM3Y interaction. The effect of contribution of the dynamic polarization potential is also studied. A semimicroscopic approximation is proposed to simulate this potential by introducing a repulsive real part extracted from the generated folded potential. Fits to data have been slightly improved by considering this approximation.

El-Azab Farid, M.; Nossair, A. M. A.; Ibraheem, Awad A.

365

{sup 7,9,10}Be elastic scattering and total reaction cross sections on a {sup 12}C target  

SciTech Connect

Elastic scattering angular distributions for {sup 7}Be, {sup 9}Be, and {sup 10}Be isotopes on {sup 12}C target were measured at laboratory energies of 18.8, 26.0, and 23.2 MeV, respectively. The analysis was performed in terms of optical model potentials using Woods-Saxon and double-folding form factors. Also, continuum discretized coupled-channels calculations were performed for {sup 7}Be and {sup 9}Be + {sup 12}C systems to infer the role of breakup in the elastic scattering. For the {sup 10}Be + {sup 12}C system, bound states coupled-channels calculations were considered. Moreover, total reaction cross sections were deduced from the elastic scattering analysis and compared with published data on other weakly and tightly bound projectiles elastically scattered on the {sup 12}C target, as a function of energy.

Zamora, J. C.; Guimaraes, V.; Barioni, A.; Lepine-Szily, A.; Lichtenthaeler, R.; Faria, P. N. de; Mendes, D. R. Jr.; Gasques, L. R.; Scarduelli, V.; Pires, K. C. C.; Morcelle, V.; Leistenschneider, E.; Condori, R. P.; Zagatto, V. A.; Morais, M. C.; Crema, E. [Instituto de Fisica, Universidade de Sao Paulo, P.O. Box 66318, 05389-970 Sao Paulo, SP (Brazil); Shorto, J. M. B. [Instituto de Pesquisas Energeticas e Nucleares, IPEN-CNEN, Sao Paulo, SP (Brazil)

2011-09-15

366

Energy storage in carbon nanotube super-springs  

E-print Network

A new technology is proposed for lightweight, high density energy storage. The objective of this thesis is to study the potential of storing energy in the elastic deformation of carbon nanotubes (CNTs). Prior experimental ...

Hill, Frances Ann

2008-01-01

367

Probing potential energy curves of C{sub 2}{sup -} by translational energy spectrometry  

SciTech Connect

We present studies on collision induced dissociation of C{sub 2}{sup -} with Ar at an impact energy of 15 keV. The C{sup -} fragment ion kinetic-energy release (KER) distribution is measured and is used to compute the KER in the center of mass (c.m.) frame (KER{sub c.m.}). We employ the reflection method to deduce an effective repulsive potential-energy curve for the molecular anion that is otherwise difficult to evaluate from quantum computational methods. The nuclear wave packet of the molecular ion in the initial ground state is computed by the semiclassical WKB method using the potential-energy curve of the {sup 2}{sigma}{sub g}{sup +} ground electronic state calculated by an ab initio quantum computation method. The ground-state nuclear wave packet is reflected on a parametrized repulsive potential-energy curve where the parameters are determined by fitting the measured KER{sub c.m.} with the calculated KER distribution.

Gupta, A.K. [Nuclear Physics Division, Bhabha Atomic Research Center, Mumbai 400 085 (India); Aravind, G.; Krishnamurthy, M. [Tata Institute of Fundamental Research, 1 Homi Bhabha Road, Bombay 400 005 (India)

2004-03-01

368

Potential system efficiencies for MEMS vibration energy harvesting  

Microsoft Academic Search

Reliable power sources are needed for portable micro-electromechanical systems (MEMS) devices such as wireless automobile tire pressure sensors. Vibration is an ubiquitous energy source that maybe 'harvested' as electrical energy at the site of the MEMS device. Existing vibration energy harvesting systems use either a piezoelectric or an electromagnetic transducer to convert vibrations into electrical energy. This electrical energy is

S. Behrens

2007-01-01

369

Energy conservation and retrofitting potential in Hellenic hotels  

Microsoft Academic Search

Energy consumption data from 158 Hellenic hotels and estimated energy savings that result from the use of practical retrofitting techniques, materials and new energy efficient systems are presented. The data were collected during an extensive energy audit of buildings that was carried out in Hellas, within the frame of a National Energy Programme sponsored by the CEC VALOREN Programme, for

M. Santamouris; C. A. Balaras; E. Dascalaki; A. Argiriou; A. Gaglia

1996-01-01

370

Industrial energy utilisation in Karnataka and potential savings  

Microsoft Academic Search

Energy is essential for industrial production. Because of the past abundance of low-cost energy, historically, the rate of social progress among industrial societies has not been limited by energy availability. Energy cost has not been significant when compared with no energy use. Mechanisation of agriculture, increased use of electrical appliances in the domestic sector and rapid industrialisation to meet the

T. V. Ramachandra; D. K. Subramanian

1997-01-01

371

Material and energy recovery in integrated waste management systems: the potential for energy recovery.  

PubMed

This article is part of a set of six coordinated papers reporting the main findings of a research project carried out by five Italian universities on "Material and energy recovery in Integrated Waste Management Systems (IWMS)". An overview of the project and a summary of the most relevant results can be found in the introductory article of the series. This paper describes the work related to the evaluation of mass and energy balances, which has consisted of three major efforts (i) development of a model for quantifying the energy content and the elemental compositions of the waste streams appearing in a IWMS; (ii) upgrade of an earlier model to predict the performances of Waste-to-Energy (WtE) plants; (iii) evaluation of mass and energy balances of all the scenarios and the recovery paths considered in the project. Results show that not only the amount of material available for energy recovery is significantly higher than the Unsorted Residual Waste (URW) left after Separate Collection (SC), because selection and recycling generate significant amounts of residues, but its heating value is higher than that of the original, gross waste. Therefore, the energy potential of what is left after recycling is always higher than the complement to 100% of the Source Separation Level (SSL). Also, increasing SSL has marginal effects on the potential for energy recovery: nearly doubling SSL (from 35% to 65%) reduces the energy potential only by one fourth. Consequently, even at high SSL energy recovery is a fundamental step of a sustainable waste management system. Variations of SSL do bring about variations of the composition, heating value and moisture content of the material fed to WtE plants, but these variations (i) are smaller than one can expect; (ii) have marginal effects on the performances of the WtE plant. These considerations suggest that the mere value of SSL is not a good indicator of the quality of the waste management system, nor of its energy and environmental outcome. Given the well-known dependence of the efficiency of steam power plants with their power output, the efficiency of energy recovery crucially depends on the size of the IWMS served by the WtE plant. A fivefold increase of the amount of gross waste handled in the IWMS (from 150,000 to 750,000 tons per year of gross waste) allows increasing the electric efficiencies of the WtE plant by about 6-7 percentage points (from 21-23% to 28.5% circa). PMID:21689919

Consonni, Stefano; Viganò, Federico

2011-01-01

372

Potential Peak Load Reductions From Residential Energy Efficient Upgrades  

E-print Network

are then combined into a package to assess the synergistic demand and energy impacts. A sensitivity analysis is then performed to assess the impacts of housing characteristics on estimated demand and energy savings. Finally, the demand, energy, and environmental...

Meisegeier, D.; Howes, M.; King, D.; Hall, J.

2002-01-01

373

VOLUME 45, NUMBER 10 P HYSI C AL REVIEW LE TTERS 8 SEPTEMBER 1980 ity a nonlocal potential which could fit neutron  

E-print Network

could fit neutron elastic scattering data in the energy range from 0.4 to 24 MeV and where the optical a nonlocal potential, which is not explicitly energy-dependent, which describes elastic nucleon scattering usefully expressed in Eulerian vari- systems possess Poincare invariants that influ- abIes. These two

Morrison, Philip J.,

374

Elastic scattering in the 6,7Li + 80Se systems  

NASA Astrophysics Data System (ADS)

Elastic-scattering angular distributions for the 6,7Li + 80Se systems were measured at center-of-mass energies from below to above the Coulomb barrier, 13 ? Ec.m.? 24 MeV. The experimental elastic-scattering cross sections were analyzed within the framework of the optical model to study the energy dependence of the real and imaginary parts of the nuclear-interaction potential. The main objective was to investigate the threshold anomaly in those weakly bound systems. The behavior of the calculated potentials as a function of energy indicates that our results are qualitatively consistent with the dispersion relation. The threshold anomaly was observed in the 7Li + 80Se system and for the 6Li + 80Se system a breakup threshold anomaly is apparent. An analysis of the absorptive processes, involved in the discussion of the experimental results, was performed using the phenomenological optical potentials that best fit the experimental data.

Fimiani, L.; Figueira, J. M.; Martí, G. V.; Testoni, J. E.; Pacheco, A. J.; Cárdenas, W. H. Z.; Arazi, A.; Capurro, O. A.; Cardona, M. A.; Carnelli, P.; de Barbará, E.; Hojman, D.; Martinez Heimann, D.; Negri, A. E.

2012-10-01

375

Material and energy recovery in integrated waste management systems: The potential for energy recovery  

SciTech Connect

Highlights: > The amount of waste available for energy recovery is significantly higher than the Unsorted Residual Waste (URW). > Its energy potential is always higher than the complement to 100% of the Source Separation Level (SSL). > Increasing SSL has marginal effects on the potential for energy recovery. > Variations in the composition of the waste fed to WtE plants affect only marginally their performances. > A large WtE plant with a treatment capacity some times higher than a small plant achieves electric efficiency appreciably higher. - Abstract: This article is part of a set of six coordinated papers reporting the main findings of a research project carried out by five Italian universities on 'Material and energy recovery in Integrated Waste Management Systems (IWMS)'. An overview of the project and a summary of the most relevant results can be found in the introductory article of the series. This paper describes the work related to the evaluation of mass and energy balances, which has consisted of three major efforts (i) development of a model for quantifying the energy content and the elemental compositions of the waste streams appearing in a IWMS; (ii) upgrade of an earlier model to predict the performances of Waste-to-Energy (WtE) plants; (iii) evaluation of mass and energy balances of all the scenarios and the recovery paths considered in the project. Results show that not only the amount of material available for energy recovery is significantly higher than the Unsorted Residual Waste (URW) left after Separate Collection (SC), because selection and recycling generate significant amounts of residues, but its heating value is higher than that of the original, gross waste. Therefore, the energy potential of what is left after recycling is always higher than the complement to 100% of the Source Separation Level (SSL). Also, increasing SSL has marginal effects on the potential for energy recovery: nearly doubling SSL (from 35% to 65%) reduces the energy potential only by one fourth. Consequently, even at high SSL energy recovery is a fundamental step of a sustainable waste management system. Variations of SSL do bring about variations of the composition, heating value and moisture content of the material fed to WtE plants, but these variations (i) are smaller than one can expect; (ii) have marginal effects on the performances of the WtE plant. These considerations suggest that the mere value of SSL is not a good indicator of the quality of the waste management system, nor of its energy and environmental outcome. Given the well-known dependence of the efficiency of steam power plants with their power output, the efficiency of energy recovery crucially depends on the size of the IWMS served by the WtE plant. A fivefold increase of the amount of gross waste handled in the IWMS (from 150,000 to 750,000 tons per year of gross waste) allows increasing the electric efficiencies of the WtE plant by about 6-7 percentage points (from 21-23% to 28.5% circa).

Consonni, Stefano [Department of Energy, Politecnico di Milano, Via Lambruschini 4, 20156 Milan (Italy); LEAP - Laboratorio Energia Ambiente Piacenza, Via Bixio 27, 29100 Piacenza (Italy); Vigano, Federico, E-mail: federico.vigano@polimi.it [Department of Energy, Politecnico di Milano, Via Lambruschini 4, 20156 Milan (Italy); LEAP -Laboratorio Energia Ambiente Piacenza, Via Bixio 27, 29100 Piacenza (Italy)

2011-09-15

376

(Molecular understanding of mutagenicity using potential energy methods)  

SciTech Connect

The objective of our work has been, for many year, to elucidate on a molecular level at atomic resolution the structures of DNAs modified by highly mutagenic polycyclic aromatic amines and hydrocarbons, and their less mutagenic chemically related analogs and unmodified DNAs, as controls. The ultimate purpose of this undertaking is to obtain an understanding of the relationship DNA structures and mutagenicity. Our methods for elucidating structures are computational, but we keep in close contact with experimental developments, and have, very recently, been able to incorporate the first experimental information from NMR studies by other workers in our calculations. The specific computational methods we employ are minimized potential energy calculations using the torsion angle space program DUPLEX, developed and written by Dr. Brain Hingerty to yield static views. Molecular dynamics simulations of the important static structures with full solvation and salt are carried out with the program AMBER; this yields mobile views in a milieu that best mimics the natural environment of the cell. In addition, we have been developing new strategies for searching conformation space and building DNA duplexes from favored subunit structures. 30 refs., 12 figs.

Broyde, S.

1990-01-01

377

Molecular understanding of mutagenicity using potential energy methods  

SciTech Connect

Our objective, has been to elucidate on a molecular level, at atomic resolution, the structures of DNAs modified by 2-aminofluorene and its N-acetyl derivative, 2-acetylaminofluorene (AAF). The underlying hypothesis is that DNA replicates with reduced fidelity when its normal right-handed B-structure is altered, and one result is a higher mutation rate. This change in structure may occur normally at a low incidence, for example by the formation of hairpin loops in appropriate sequences, but it may be enhanced greatly after covalent modification by a mutagenic substance. We use computational methods and have been able to incorporate the first data from NMR studies in our calculations. Computational approaches are important because x-ray and spectroscopic studies have not succeeded in producing atomic resolution views of mutagen and carcinogen-oligonucleotide adducts. The specific methods that we employ are minimized potential energy calculations using the torsion angle space molecular mechanics program DUPLEX to yield static views. Molecular dynamics simulations, with full solvent and salt, of the important static structures are carried out with the program AMBER; this yields mobile views in a medium that mimics the natural aqueous environment of the cell as well as can be done with current available computing resources.

Broyde, S.; Shapiro, R.

1992-07-01

378

Calculation of free-energy differences and potentials of mean force by a multi-energy gap method  

E-print Network

Calculation of free-energy differences and potentials of mean force by a multi-energy gap method the convergence of free-energy calculations. It introduces a bias factor in Monte Carlo simulations or.e., the difference in energy function between two states, and is therefore specifically designed for calculating free-energy

Weston, Ken

379

First-principle study of structural, elastic and electronic properties of Th monopnictides  

NASA Astrophysics Data System (ADS)

In this work, first principles calculation of structural, electronic and elastic properties of thorium monopnictides ThX (N, P, As, Sb and Bi) are presented. The calculations are performed by a developed full-potential augmented plane wave plus local orbitals (FP-L/APW+lo) method within the density functional theory (DFT). The exchange and correlation potential energies are treated according to the generalized gradient approximation (GGA) using the Perdew, Burke, Ernzerhof (PBE) parameterization, and the local density approximation (LDA). We have calculated the lattice parameters, bulk modulii and the first pressure derivatives of the bulk modulii. The elastic properties of the studied compounds are only investigated in the most stable calculated phase. We have obtained Young's modulus, shear modulus, Poisson's ratio, anisotropy factor and Kleinman parameter by the aid of the calculated elastic constants. We discuss the total and partial densities of states and charge densities.

Amari, S.; Méçabih, S.; Abbar, B.; Bouhafs, B.

2014-11-01

380

Transportation Energy Futures Series: Potential for Energy Efficiency Improvement Beyond the Light-Duty-Vehicle Sector  

SciTech Connect

Considerable research has focused on energy efficiency and fuel substitution options for light-duty vehicles, while much less attention has been given to medium- and heavy-duty trucks, buses, aircraft, marine vessels, trains, pipeline, and off-road equipment. This report brings together the salient findings from an extensive review of literature on future energy efficiency options for these non-light-duty modes. Projected activity increases to 2050 are combined with forecasts of overall fuel efficiency improvement potential to estimate the future total petroleum and greenhouse gas (GHG) emissions relative to current levels. This is one of a series of reports produced as a result of the Transportation Energy Futures (TEF) project, a Department of Energy-sponsored multi-agency project initiated to pinpoint underexplored strategies for abating GHGs and reducing petroleum dependence related to transportation.

Vyas, A. D.; Patel, D. M.; Bertram, K. M.

2013-03-01

381

Elastic constants of martensite  

Microsoft Academic Search

The elastic constants of Fe?Ni?C martensite are increased by retained austenite. Also, nickel markedly decreases the elastic\\u000a constants of such martensite. Therefore, to properly evaluate the effect of carbon on the elastic constants of Fe?Ni?C martensite,\\u000a it is necessary to first correct for both retained austenite and nickel content. When these corrections are made, both the\\u000a Young's modulus and the

G. R. Speich; W. C. Leslie

1973-01-01

382

Biomass energy potential and future prospect in Sudan  

Microsoft Academic Search

Sudan is an agricultural country with fertile land, plenty of water resources, livestock, forestry resources, and agricultural residues. Sudan is an energy importing country and the energy requirements have been supplied through imports that have caused financial problems. Because of the economical problems in Sudan today, the Sudanese energy policy should be concentrated on assurance of energy supply, reliability, domestic

Abdeen M. Omer

2005-01-01

383

Accuracy of the energy partitioning data obtained by classical trajectory calculations on potential energy surfaces constructed by interpolation  

E-print Network

Accuracy of the energy partitioning data obtained by classical trajectory calculations on potential of the classical trajectory calculation on a potential energy surface PES constructed by interpolation of the difficulties in this method is the need to calculate energies at many points for a faithful rep- resentation

Kim, Myung Soo

384

Hadron structure and elastic scattering  

E-print Network

When colliding, the high energy hadrons can either produce new particles or scatter elastically without change of their quantum numbers and other particles produced. Namely elastic scatterings of hadrons are considered in this paper. The general machinery of their theoretical treatment is described. Some new experimental data are presented and confronted to phenomenological approaches. The internal structure of hadrons is the main subject of these studies. Its impact on properties of their interactions is reviewed. It is shown that protons become larger and darker with increase of their collision energy and reveal some substructure. The violation of the geometric scaling in the diffraction cone and new problems of description of differential cross sections outside it are described.

I. M. Dremin

2013-11-17

385

Hadron Structure and Elastic Scattering  

NASA Astrophysics Data System (ADS)

When colliding, the high energy hadrons can either produce new particles or scatter elastically without change of their quantum numbers and other particles produced. Namely elastic scatterings of hadrons are considered in this paper. The general machinery of their theoretical treatment is described. Some new experimental data are presented and confronted to phenomenological approaches. The internal structure of hadrons is the main subject of these studies. Its impact on properties of their interactions is reviewed. It is shown that protons become larger and darker with increase of their collision energy and reveal some substructure. The violation of the geometric scaling in the diffraction cone and new problems of description of differential cross sections outside it are described.

Dremin, I.

386

X-ray diffraction study of residual elastic stress and microstructure of near-surface layers in nickel-titanium alloy irradiated with low-energy high-current electron beams  

NASA Astrophysics Data System (ADS)

In the work, we compare quantitative estimates of residual stresses in nickel-titanium (NiTi) alloy surface layers after electron beam treatment. The quantitative estimates to be compared were taken using X-ray diffraction (XRD) techniques with symmetric and asymmetric Bragg diffraction geometries. A method of quantitative X-ray diffraction estimation of residual stresses in materials with gradient changes in microstructure and physical properties, including elastic moduli, is described. It is found that in a NiTi specimen with one side irradiated by a low-energy high-current electron beam, the maximum residual elastic stresses ? ?550 MPa are localized in the modified surface layer (melted by the electron beam and rapidly quenched), whereas the residual elastic stresses in the underlying layer with initial B2 structure are no greater than ?100 MPa. It is for this reason that stress-induced B19? martensite is formed in the material layer beneath the modified layer.

Meisner, L. L.; Lotkov, A. I.; Ostapenko, M. G.; Gudimova, E. Yu.

2013-09-01

387

Mathematical Foundations of Elasticity TheoryElasticity Theory  

E-print Network

Mathematical Foundations of Elasticity TheoryElasticity Theory John Ball Oxford Centre (elastic rod) 1821 Navier, special case of linear elasticity via molecular model (Dalton's atomic theory was 1807)(Dalton's atomic theory was 1807) 1822 Cauchy, stress, nonlinear and linear elasticity For a long

Ball, John M.

388

Parametric interatomic potential for graphene  

NASA Astrophysics Data System (ADS)

A parametric interatomic potential is constructed for graphene. The potential energy consists of two parts: a bond energy function and a radial interaction energy function. The bond energy function is based on the Tersoff-Brenner potential model. It includes angular terms and explicitly accounts for flexural deformation of the lattice normal to the plane of graphene. It determines the cohesive energy of graphene and its equilibrium lattice constant. The radial energy function has been chosen such that it does not contribute to the binding energy or the equilibrium lattice constant but contributes to the interatomic force constants. The range of interaction of each atom extends up to its fourth-neighbor atoms in contrast to the Tersoff-Brenner potential, which extends only up to second neighbors. The parameters of the potential are obtained by fitting the calculated values to the cohesive energy, lattice constant, elastic constants, and phonon frequencies of graphene. The values of the force constants between an atom and other atoms that are within its fourth-neighbor distance are calculated. Analytical expressions are given for the elastic constants and the flexural rigidity of graphene. The flexural rigidity of the graphene lattice is found to be 2.13 eV, which is much higher than 0.797 eV calculated earlier using the Tersoff-Brenner potential.

Tewary, V. K.; Yang, B.

2009-02-01

389

Threshold anomaly in the elastic scattering of the weakly bound projectile 7Li on the medium-mass target 116Sn  

NASA Astrophysics Data System (ADS)

Elastic scattering angular distributions using the weakly bound projectile 7Li on medium-mass target 116Sn were measured for 10 different beam energies from much below to above the Coulomb barrier. Optical model (OM) analysis was carried out using the famous double folding São Paulo Potential (SPP) to investigate the energy dependence of the interacting polarizing potentials. The absence of the usual Threshold Anomaly (TA) is observed. Thus this unusual behavior of the interacting potentials indicates the coupling of the breakup channels with the elastic ones.

Deshmukh, N. N.; Mukherjee, S.; Nayak, B. K.; Biswas, D. C.; Santra, S.; Appannababu, S.; Mirgule, E. T.; Saxena, A.; Patel, D.; Choudhury, R. K.; Lubian, J.; Gomes, P. R. S.

2012-02-01

390

Modeling Elasticity in Crystal Growth  

E-print Network

A new model of crystal growth is presented that describes the phenomena on atomic length and diffusive time scales. The former incorporates elastic and plastic deformation in a natural manner, and the latter enables access to times scales much larger than conventional atomic methods. The model is shown to be consistent with the predictions of Read and Shockley for grain boundary energy, and Matthews and Blakeslee for misfit dislocations in epitaxial growth.

K. R. Elder; Mark Katakowski; Mikko Haataja; Martin Grant

2001-07-18

391

Crack initiation in elastic bodies  

Microsoft Academic Search

In this paper we study the crack initiation in a hyper-elastic body governed by a Griffith's type energy. We prove that, during a load process through a time dependent boundary datum of the type $t \\\\to t g(x)$ and in absence of strong singularities (this is the case of homogeneous isotropic materials) the crack initiation is brutal, i.e., a big

Antonin Chambolle; Alessandro Giacomini; Marcello Ponsiglione

2005-01-01

392

Zero-energy states for a class of quasi-exactly solvable rational potentials  

E-print Network

Quasi-exactly solvable rational potentials with known zero-energy solutions of the Schro\\" odinger equation are constructed by starting from exactly solvable potentials for which the Schr\\" odinger equation admits an so(2,1) potential algebra. For some of them, the zero-energy wave function is shown to be normalizable and to describe a bound state.

B. Bagchi; C. Quesne

1997-03-20

393

Deuteron elastic scattering from the tin isotopes  

Microsoft Academic Search

Angular distributions are presented for the elastic scattering of 20 MeV deuterons from 112,118,124Sn and of 27 MeV deuterons from 112,118,119,124Sn. Satisfactory fits to the data were obtained using both the standard optical model and the reformulated optical model of Greenlees, Pyle and Tang. Comparison with potentials obtained from proton elastic scattering showed consistently smaller mean square radii for the

Lesley A. Winsborrow; G. L. Thomas; C. F. Coleman; T. W. Conlon

1972-01-01

394

A comparative study of the He-Sb(111) interaction potential from close-coupling calculations and helium atom scattering experiments  

NASA Astrophysics Data System (ADS)

The exact elastic close-coupling formalism is used to compare the performance of several interaction potentials suggested in literature for describing the measured elastic diffraction peak intensities in helium scattering experiments. The coupling parameters have been analytically calculated for the corrugated Morse potential on a hexagonal surface structure and adapted for usage with similar interaction potentials. The potentials used have been fitted to previously known bound state energies complemented by two additional levels which are found by improving energy resolution. It is established that the shifted Morse potential reproduces the experimental He-Sb(111) bound state more closely than the other considered potential shapes. The performance of several interaction potentials in describing the elastic scattering intensities is presented and discussed. Morse and Morse-related potentials provide the best compromise for the description of elastic scattering intensities. The different effects of the potential shape were determined by comparing the calculated scattering intensities.

Kraus, Patrick; Mayrhofer-Reinhartshuber, Michael; Gösweiner, Christian; Apolloner, Florian; Miret-Artés, Salvador; Ernst, Wolfgang E.

2014-12-01

395

By-products: oil sorbents as a potential energy source.  

PubMed

The present study investigated the utilization of an industrial by-product, lignite fly ash, in oil pollution treatment, with the further potential profit of energy production. The properties of lignite fly ash, such as fine particle size, porosity, hydrophobic character, combined with the properties, such as high porosity and low specific gravity, of an agricultural by-product, namely sawdust, resulted in an effective oil-sorbent material. The materials were mixed either in the dry state or in aqueous solution. The oil sorption behaviour of the fly ash-sawdust mixtures was investigated in both marine and dry environments. Mixtures containing fly ash and 15-25% w/w sawdust performed better than each material alone when added to oil spills in a marine environment, as they formed a cohesive semi-solid phase, adsorbing almost no water, floating on the water surface and allowing total oil removal. For the clean-up of an oil spill 0.5 mm thick with surface area 1000 m(2), 225-255 kg of lignite fly ash can be utilized with the addition of 15-25% w/w sawdust. Fly ash-sawdust mixtures have also proved efficient for oil spill clean-up on land, since their oil sorption capacity in dry conditions was at least 0.6-1.4 g oil g(-1) mixture. The higher calorific value of the resultant oil-fly ash-sawdust mixtures increased up to that of bituminous coal and oil and exceeded that of lignite, thereby encouraging their utilization as alternative fuels especially in the cement industry, suggesting that the remaining ash can contribute in clinker production. PMID:23179513

Karakasi, Olga K; Moutsatsou, Angeliki

2013-04-01

396

Phase Transition and Elastic Properties of La-Compounds  

SciTech Connect

The Phase transition and elastic properties of La-monochalcogenides have been investigated under pressure by means of a modified charge-transfer potential model which incorporates the Coulomb interaction modified by Coulomb screening due to the delocalization of electron of rare-earth atom leading to many-body interactions, covalency effect and overlap repulsion extended up to second-nearest neighbours. Under high pressure the coordination increases and they transform from rock-salt to CsCl structure. The calculated values of cohesive energy, lattice constant, phase transition pressure, relative volume collapse and harmonic elastic moduli their agree well with the available measured data and better than those computed by earlier workers. Present model is capable of explaining the Cauchy's discrepancy correctly.

Raypuria, G. S.; Singh, K. C.; Baraiya, A. K.; Gupta, D. C. [Condensed Matter Theory Group, School of Studies in Physics, Jiwaji University, GWALIOR - 474 011 (India); Department of Physics, Govt. K.R.G.P.G. Autonomous College, Gwalior - 474 001 (India)

2011-07-15

397

DNA Twist Elasticity: Mechanics and Thermal Fluctuations  

E-print Network

The elastic properties of semiflexible polymers are of great importance in biology. There are experiments on biopolymers like double stranded DNA, which twist and stretch single molecules to probe their elastic properties. It is known that thermal fluctuations play an important role in determining molecular elastic properties, but a full theoretical treatment of the problem of twist elasticity of fluctuating ribbons using the simplest worm like chain model (WLC) remains elusive. In this paper, we approach this problem by taking first a mechanical approach and then incorporating thermal effects in a quadratic approximation applying the Gelfand-Yaglom (GY) method for computing fluctuation determinants. Our study interpolates between mechanics and statistical mechanics in a controlled way and shows how profoundly thermal fluctuations affect the elasticity of semiflexible polymers. The new results contained here are: 1) a detailed study of the minimum energy configurations with explicit expressions for their energy and writhe and plots of the extension versus Link for these configurations. 2) a study of fluctuations around the local minima of energy and approximate analytical formulae for the free energy of stretched twisted polymers derived by the Gelfand Yaglom method. We use insights derived from our mechanical approach to suggest calculational schemes that lead to an improved treatment of thermal fluctuations. From the derived formulae, predictions of the WLC model for molecular elasticity can be worked out for comparison against numerical simulations and experiments.

Supurna Sinha; Joseph Samuel

2010-11-30

398

Calculation of Protein Conformation by Global Optimization of a Potential Energy Function  

E-print Network

Calculation of Protein Conformation by Global Optimization of a Potential Energy Function Jooyoung- vided by CASP3. The approach is based exclusively on the global optimization of a potential energy function for a united-residue model by conformational space annealing, followed by energy refinement using

Lee, Jooyoung

399

Marine renewable energy: potential benefits to biodiversity? An urgent call for research  

E-print Network

Marine renewable energy: potential benefits to biodiversity? An urgent call for research Richard 1 Centre for Ecology and Conservation and Peninsula Research Institute for Marine Renewable Energy. Concerns over the potential impacts on biodiversity of marine renewable energy installations (MREI) include

Exeter, University of

400

PUBLISHED VERSION Free Energy Generalization of the Peierls Potential in Iron  

E-print Network

PUBLISHED VERSION Free Energy Generalization of the Peierls Potential in Iron M. R. Gilbert, P) and may be found at 10.1103/PhysRevLett.111.095502 #12;Free Energy Generalization of the Peierls Potential for bcc Fe. We compute the Peierls free energy path as a function of stress and temperature and show

401

Metastable states of ozone calculated on an accurate potential energy surface  

E-print Network

Metastable states of ozone calculated on an accurate potential energy surface Dmitri Babikov 2003 A new potential energy surface for ozone is developed. It is based on high level ab initio data compositions of ozone. Collision lifetimes are obtained over a wide energy range, which gives the spectrum

Reid, Scott A.

402

Elastic Scattering and Fusion of 6Li on 64Zn at the Barrier  

NASA Astrophysics Data System (ADS)

Elastic-scattering angular distributions for the 6Li+64Zn system were measured at energies from below to above the Coulomb barrier. The experimental data were analyzed within the optical model to study the energy dependence of the interaction potential. The results suggest the presence of the breakup threshold anomaly. Preliminary results on the fusion cross-sections for the same system are also reported.

Scuderi, V.; Strano, E.; Amorini, F.; Di Pietro, A.; Figuera, P.; Fisichella, M.; Goryunov, O.; Maiolino, C.; Lattuada, M.; Musumarra, A.; Ostashko, V.; Papa, M.; Pellegriti, M. G.; Rizzo, F.; Santonocito, D.; Torresi, D.; Zadro, M.

2011-10-01

403

Intensity of activation and timing of deactivation modulate elastic energy storage and release in a pennate muscle and account for gait-specific initiation of limb protraction in the horse.  

PubMed

The equine biceps brachii (biceps) initiates rapid limb protraction through a catapult mechanism. Elastic strain energy is slowly stored in an internal tendon and is then rapidly released to protract the forelimb. The muscle fibres are short, have little scope for length change and can therefore only shorten slowly compared with the speed at which the whole muscle must shorten, which makes them poor candidates for driving rapid limb protraction. We suggest that the muscle fibres in the biceps act to modulate the elastic energy output of the muscle-tendon unit (MTU) to meet the demands of locomotion under different conditions. We hypothesise that more elastic strain energy is stored and released from the biceps MTU during higher speed locomotion to accommodate the increase in energy required to protract the limb and that this can be achieved by varying the length change and activation conditions of the muscle. We examined the work performed by the biceps during trot and canter using an inverse dynamics analysis (IDA). We then used excised biceps muscles to determine how much work could be performed by the muscle in active and passive stretch-shorten cycles. A muscle model was developed to investigate the influence of changes in activation parameters on energy storage and energy return from the biceps MTU. Increased biceps MTU length change and increased work performed by the biceps MTU were found at canter compared with at trot. More work was performed by the ex vivo biceps MTU following activation of the muscle and by increasing muscle length change. However, the ratio of active to passive work diminished with increasing length change. The muscle model demonstrated that duration and timing of activation during stretch-shorten cycles could modulate the elastic energy storage and return from the biceps. We conclude that the equine biceps MTU acts as a tuneable spring and the contractile component functions to modulate the energy required for rapid forelimb protraction at different speeds. PMID:19617439

Lichtwark, Glen A; Watson, Johanna C; Mavrommatis, Sophia; Wilson, Alan M

2009-08-01

404

Estimation of CO2 Mitigation Potential through Renewable Energy Generation  

Microsoft Academic Search

Energy is vital input for economy and social development in every society. Presently, the global primary energy demands are met largely from oil, natural gas, coal, nuclear and hydroelectric energy among which coal is dominant thermal power stations add to environmental degradation problems through gaseous emissions, particulate matter, fly ash, bottom ash, which are very harmful to human life. The

Mohibullah; Imdadullah; I. Ashraf

2006-01-01

405

Wind energy potential mapping in Karnataka, India, using GIS  

Microsoft Academic Search

Increasing negative effects of fossil fuel combustion on the environment in addition to limited stock have forced many countries to explore and change to environmentally friendly alternatives that are renewable to sustain the increasing energy demand. Changing to renewable sources and implementation of effective conservation measures would ensure sustainability. Currently, wind energy is one of the fastest developing renewable energy

T. V. Ramachandra; B. V. Shruthi

2005-01-01

406

Energy requirements and CO2 mitigation potential of PV systems  

Microsoft Academic Search

In this paper we investigate the energy requirements of PV modules and systems and calculate the Energy Pay-Back Time for two major PV applications. Based on a review of past energy analysis studies we explain the main sources of differences and establish a \\

E. A. Alsema

1998-01-01

407

Power from Perspective: Potential future United States energy portfolios  

Microsoft Academic Search

This paper presents United States energy portfolios for the year 2030, developed from seven different Perspectives. The Perspectives are characterized by different weights placed on fourteen defining values (e.g., cost, social acceptance). The portfolios were constructed to achieve three primary goals, energy independence, energy security, and greenhouse gas reductions. The portfolios are also evaluated over a comprehensive set of secondary

Bruce Tonn; K. C. Healy; Amy Gibson; Ashutosh Ashish; Preston Cody; Drew Beres; Sam Lulla; Jim Mazur; A. J. Ritter

2009-01-01

408

Development of the Potential Energy Savings Estimation (PESE) Toolkit  

E-print Network

the corresponding energy conservation measures (ECMs) in the early phase of an EBCx project or energy retrofit project. Using the tool requires limited information about the building and the built-in HVAC system type, as well as sorted bin weather and energy...

Liu, J.; Baltazar, J. C.; Claridge, D. E.

409

Positron-inert gas differential elastic scattering  

NASA Technical Reports Server (NTRS)

Measurements are being made in a crossed beam experiment of the relative elastic differential cross section (DCS) for 5 to 300 eV positrons scattering from inert gas atoms (He, Ne, Ar, Kr, and Xe) in the angular range from 30 to 134 deg. Results obtained at energies around the positronium (Ps) formation threshold provide evidence that Ps formation and possibly other inelastic channels have an effect on the elastic scattering channel.

Kauppila, W. E.; Smith, Steven J.; Kwan, C. K.; Stein, T. S.

1990-01-01

410

A second-generation reactive empirical bond order (REBO) potential energy expression for hydrocarbons  

Microsoft Academic Search

A second-generation potential energy function for solid carbon and hydrocarbon molecules that is based on an empirical bond order formalism is presented. This potential allows for covalent bond breaking and forming with associated changes in atomic hybridization within a classical potential, producing a powerful method for modelling complex chemistry in large many-atom systems. This revised potential contains improved analytic functions

Donald W. Brenner; Olga A. Shenderova; Judith A. Harrison; Steven J. Stuart; Boris Ni; Susan B. Sinnott

2002-01-01

411

Elastic limit of silicane  

NASA Astrophysics Data System (ADS)

Silicane is a fully hydrogenated silicene-a counterpart of graphene-having promising applications in hydrogen storage with capacities larger than 6 wt%. Knowledge of its elastic limit is critical in its applications as well as tailoring its electronic properties by strain. Here we investigate the mechanical response of silicane to various strains using first-principles calculations based on density functional theory. We illustrate that non-linear elastic behavior is prominent in two-dimensional nanomaterials as opposed to bulk materials. The elastic limits defined by ultimate tensile strains are 0.22, 0.28, and 0.25 along armchair, zigzag, and biaxial directions, respectively, an increase of 29%, 33%, and 24% respectively in reference to silicene. The in-plane stiffness and Poisson ratio are reduced by a factor of 16% and 26%, respectively. However, hydrogenation/dehydrogenation has little effect on its ultimate tensile strengths. We obtained high order elastic constants for a rigorous continuum description of the nonlinear elastic response. The limitation of second, third, fourth, and fifth order elastic constants are in the strain range of 0.02, 0.08, and 0.13, and 0.21, respectively. The pressure effect on the second order elastic constants and Poisson's ratio were predicted from the third order elastic constants. Our results could provide a safe guide for promising applications and strain-engineering the functions and properties of silicane monolayers.

Peng, Qing; de, Suvranu

2014-09-01

412

Elastic limit of silicane.  

PubMed

Silicane is a fully hydrogenated silicene-a counterpart of graphene-having promising applications in hydrogen storage with capacities larger than 6 wt%. Knowledge of its elastic limit is critical in its applications as well as tailoring its electronic properties by strain. Here we investigate the mechanical response of silicane to various strains using first-principles calculations based on density functional theory. We illustrate that non-linear elastic behavior is prominent in two-dimensional nanomaterials as opposed to bulk materials. The elastic limits defined by ultimate tensile strains are 0.22, 0.28, and 0.25 along armchair, zigzag, and biaxial directions, respectively, an increase of 29%, 33%, and 24% respectively in reference to silicene. The in-plane stiffness and Poisson ratio are reduced by a factor of 16% and 26%, respectively. However, hydrogenation/dehydrogenation has little effect on its ultimate tensile strengths. We obtained high order elastic constants for a rigorous continuum description of the nonlinear elastic response. The limitation of second, third, fourth, and fifth order elastic constants are in the strain range of 0.02, 0.08, and 0.13, and 0.21, respectively. The pressure effect on the second order elastic constants and Poisson's ratio were predicted from the third order elastic constants. Our results could provide a safe guide for promising applications and strain-engineering the functions and properties of silicane monolayers. PMID:25190587

Peng, Qing; De, Suvranu

2014-10-21

413

Elastic properties of minerals  

SciTech Connect

Investigations of the elastic properties of the main rock-forming minerals were begun by T.V. Ryzhova and K.S. Aleksandrov over 30 years ago on the initiative of B.P. Belikov. At the time, information on the elasticity of single crystals in general, and especially of minerals, was very scanty. In the surveys of that time there was information on the elasticity of 20 or 30 minerals. These, as a rule, did not include the main rock-forming minerals; silicates were represented only by garnets, quartz, topaz, tourmaline, zircon, beryl, and staurolite, which are often found in nature in the form of large and fairly high-quality crystals. Then and even much later it was still necessary to prove a supposition which now seems obvious: The elastic properties of rocks, and hence the velocities of elastic (seismic) waves in the earth`s crust, are primarily determined by the elastic characteristics of the minerals composing these rocks. Proof of this assertion, with rare exceptions of mono-mineralic rocks (marble, quartzite, etc.) cannot be obtained without information on the elasticities of a sufficiently large number of minerals, primarily framework, layer, and chain silicates which constitute the basis of most rocks. This also served as the starting point and main problem of the undertakings of Aleksandrov, Ryzhova, and Belikov - systematic investigations of the elastic properties of minerals and then of various rocks. 108 refs., 7 tabs.

Aleksandrov, K.S.; Prodaivoda, G.T.

1993-09-01

414

Compressed-Air Energy Storage: Commercialization Potential and EPRI Roles in the Commercialization Process. Final Report.  

National Technical Information Service (NTIS)

This report describes an assessment of potential roles that EPRI might take to facilitate the commercial acceptance of compressed air energy storage (CAES) systems. The assessment is based on (1) detailed analyses of the market potential of utility storag...

D. W. Boyd, O. E. Buckley, C. E. Clark

1982-01-01

415

Deposition of Potential Energy in Solids by Slow, Highly Charged Ions  

NASA Astrophysics Data System (ADS)

We have measured the deposition of potential energy of slow \\(~6×105 m/s\\), highly charged ions in solids with an ion implanted silicon detector. A large fraction (about 35% or 60 keV) of the potential energy dissipated by Au69+ ions can be traced in electronic excitations deep \\(>50 nm\\) inside the solid. In contrast, only about 10% of the potential energy has been accounted for in measurements of emitted secondary particles.

Schenkel, T.; Barnes, A. V.; Niedermayr, T. R.; Hattass, M.; Newman, M. W.; Machicoane, G. A.; McDonald, J. W.; Hamza, A. V.; Schneider, D. H.

1999-11-01

416

Solar energy potential atlas for planning energy system off-grid electrification in the Republic of Djibouti  

E-print Network

1 Solar energy potential atlas for planning energy system off-grid electrification in the Republic solar resource can therefore be an interesting mean to produce energy where it is consumed. The aimWh/m². Furthermore, the solar radiation reaching Djibouti corresponded to 20 000 times the total yearly energy

Boyer, Edmond

417

On the form of free energy and specific heat in coupled thermo-elasticity with isotropic damage  

Microsoft Academic Search

This paper concerns the form of the free energy function in coupled thermo-mechanical problems with isotropic damage, particularly where damage accrues through both mechanical and thermal strains, and when the material is exposed to elevated temperatures. We show that with the normal assumption of a constant specific heat coefficient, mechanical dissipation is negative and so the second law of thermodynamics

J. Stabler; G. Baker

2000-01-01

418

Calculation of electron-impact rotationally elastic total cross sections for NH{sub 3}, H{sub 2}S, and PH{sub 3} over the energy range from 0.01 eV to 2 keV  

SciTech Connect

This paper report results of calculation of the total cross section Q{sub T} for electron impact on NH{sub 3}, H{sub 2}S, and PH{sub 3} over a wide range of incident energies from 0.01 eV to 2 keV. Total cross sections Q{sub T} (elastic plus electronic excitation) for incident energies below the ionization threshold of the target were calculated using the UK molecular R-matrix code through the Quantemol-N software package and cross sections at higher energies were derived using the spherical complex optical potential formalism. The two methods are found to give self-consistent values where they overlap. The present results are, in general, found to be in good agreement with previous experimental and theoretical results.

Limbachiya, Chetan [P. S. Science College, Kadi 382 715, Gujarat (India); Vinodkumar, Minaxi [V. P. and R. P. T. P. Science College, Vallabh Vidyanagar 388 120, Gujarat (India); Mason, Nigel [Department of Physics and Astronomy, Open University, Milton Keynes, MK7 6AA (United Kingdom)

2011-04-15

419

Methodology for the Determination of Potential Energy Savings in Commercial Buildings  

E-print Network

This paper describes a methodology to determine potential energy savings of buildings with limited information. This methodology is based upon the simplified energy analysis procedure of heating, ventilation and air condition (HVAC) systems...

Baltazar-Cervantes, J. C.; Claridge, D. E.

2007-01-01

420

Elastic scattering and heavy residue production in the collisions 6,7Li+64 Zn around the Coulomb barrier  

NASA Astrophysics Data System (ADS)

Elastic scattering angular distributions and heavy residue production cross sections have been measured at different energies around the Coulomb barrier for the systems 6,7Li+64Zn. Optical model fits of the elastic angular distributions were performed using a renormalized double folding potential and absence of usual threshold anomaly in the optical potential was found. Excitation functions for heavy residue production have been measured using an activation technique. Comparison of the data with the results of different calculations show that complete fusion is the dominant reaction mechanism above the barrier, whereas the heavy residue yield below the barrier is mainly due to incomplete fusion and transfer.

Figuera, P.; Di Pietro, A.; Strano, E.; Fisichella, M.; Lattuada, M.; Milin, M.; Musumarra, A.; Ostashko, V.; Pellegriti, M. G.; Randisi, G.; Scuderi, V.; Torresi, D.; Zadroa, M.

2013-12-01

421

Global energy scenarios and the potential role of fusion energy in the 21st century  

NASA Astrophysics Data System (ADS)

Global energy usage is increasing at about 2% p.a. The expansion is related to population growth and to demand for economic growth and higher standards of living, despite some economies in energy use per unit GNP. A severalfold increase in global electricity demand by the middle of the 21st century seems inevitable, with the largest increment from large-population developing countries such as China and India. Currently, most electricity is provided by carbon-based fossil fuels, by hydroelectricity and by nuclear fission. Fusion, with its potential to provide electricity from large central power stations could help meet a significant part of this expanding demand. It will have to be broadly competitive with established generating methods. Current advances in fusion research indicate good prospects for technical demonstration of fusion electricity generation. Research and development of materials for fusion energy is needed now not only for demonstration plant, but also to enhance the estimates of the competitivity of fusion and to maximise its economic and environmental potential.

Pease, R. S.

1992-09-01

422

Potential solar energy utilization for winter residential space heating in Georgia  

Microsoft Academic Search

A procedure for determining mean monthly space heating energy needs, solar radiation availability and solar energy collection is given. For the four Georgia locations of Atlanta, Augusta, Macon and Savannah, results indicate that solar energy may potentially meet a large portion of the total space heating needs for both a modern conventional insulated home and a highly energy efficient home

Suckling

1981-01-01

423

Solar energy for heat and electricity: the potential for mitigating climate change  

E-print Network

Solar energy for heat and electricity: the potential for mitigating climate change Dr N.J. EkiNs-DaukEs Executive summary Why are we interested in using solar energy? Sunlight provides the energy source countries, solar energy can seem less attractive than conventional sources due to its intermittent nature

424

Soft-Rotator Coupled Channels Global Optical Potential for A=24-122 Mass Region Nuclides up to 200-MeV Incident Nucleon Energies  

SciTech Connect

A coupled-channels optical model with a coupling scheme based on nuclear wave functions of the soft-rotator model was applied to analyze experimental nucleon-nucleus interaction data for even-even nuclides with mass number A=24-122. We found that all the available data (total cross sections, angular distributions of elastically and inelastically scattered nucleons, and reaction cross sections) for these nuclides can be described to a good accuracy using an optical potential having smooth dependencies of potential values, radii, and diffuseness on the mass number. The individual properties of the target nuclides are accounted for by individuality of the nuclear Hamiltonian parameters, adjusted to reproduce the low-lying collective level structure, Fermi energies, and deformation parameters.

Soukhovitski, Efrem Sh. [Joint Institute of Energy and Nuclear Research-Sosny, Academician A.K. Krasin Str. 99, Minsk 220109 (Belarus); Chiba, Satoshi [Japan Atomic Energy Research Institute, Tokai, Naka, Ibaraki 319-1195 (Japan); Lee, Jeong-Yeon [Department of Physics, Sejong University, Seoul 143-747 (Korea, Republic of)

2005-05-24

425

Recognising the potential for renewable energy heating and cooling  

Microsoft Academic Search

Heating and cooling in the industrial, commercial, and domestic sectors constitute around 40–50% of total global final energy demand. A wide range of renewable energy heating and cooling (REHC) technologies exists but they are presently only used to meet around 2–3% of total world demand (excluding from traditional biomass). Several of these technologies are mature, their markets are growing, and

Kristin Seyboth; Luuk Beurskens; Ole Langniss; Ralph E. H. Sims

2008-01-01

426

Solar Energy Utilisation Potential of three different Swiss Urban Sites  

Microsoft Academic Search

Besides providing a more efficient energy use, a large scale application of solar energy technologies in the urban context will be required in the upcoming decades to achieve a drastic reduction of greenhouse gas emissions in the biosphere. Three different urban sites, representative of three of the largest Swiss cities (Basel, Geneva and Lausanne), were examined in order to assess

M Montavon; J-L Scartezzini; R Compagnon

427

Potential utilization of solar energy for industrial processes in Egypt  

Microsoft Academic Search

During the last decade, people all over the world are using in alarming rates the costly supply of fossil and conventional fuels as the main source of energy. As the strategic reserves of these natural resources being quickly depleted, it appears as an urgent problem of special importance to mankind to search for alternative natural resources of energy which can

Abd El-Salam

1980-01-01

428

Potential for Altering Energy Partition in the Lactating Cow  

Microsoft Academic Search

Partitioning of nutrients in lactating cows is discussed in terms of processes requiring energy associated with main- tenance and production with emphasis upon kinetic properties that determine patterns and rates of nutrient use and nutrient interactions. Rates of nutrient oxidation by tissues are determined largely by energy expenditures, con- centrations of nutrients in blood, and relative affinities of tissues for

B. R. Baldwin; N. E. Forsberg; C. Y. Hu

1985-01-01

429

Biomass energy in China and its potential Li Jingjing  

E-print Network

Development #12;pollution. Household members, especially women and children, are exposed to pollutant.R.China Zhuang Xing Center for Renewable Energy Development, Energy Research Institute, State Development creates a burden on women and children, which reduces their time available for more productive activities

430

Solar biomass energy: an overview of u.s. Potential.  

PubMed

The U.S. annual biomass production for food, lumber, paper, and fiber, if used exclusively for energy, would provide 25 percent of current energy requirements. The collection of unharvested wood residues and cull trees for direct use as fuel for small nearby space-heating applications-especially for peak winter conditions-is an important near-term solar energy opportunity. Improved management of hundreds of millions of acres of productive forest land is an important opportunity for the long term. Harvest of cropland residues for energy values, new biomass production using intensive short-rotation silviculture, resubstitution of natural products for petroleum-based synthetics, and forest management for large-scale production of electricity and synthetic fuels are judged to be less appropriate directions for the U.S. energy system to take. PMID:17844401

Burwell, C C

1978-03-10

431

Near- and subbarrier elastic and quasielastic scattering of the weakly bound {sup 6}Li projectile on {sup 144}Sm  

SciTech Connect

High-precision data of backward-angle elastic and quasielastic scattering for the weakly bound {sup 6}Li projectile on {sup 144}Sm target at deep-sub-barrier, near-, and above-barrier energies were measured. From the deep-sub-barrier data, the surface diffuseness of the nuclear interacting potential was studied. Barrier distributions were extracted from the first derivatives of the elastic and quasielastic excitation functions. It is shown that sequential breakup through the first resonant state of the {sup 6}Li is an important channel to be included in coupled-channels calculations, even at deep-sub-barrier energies.

Monteiro, D. S.; Otomar, D. R.; Lubian, J.; Gomes, P. R. S. [Instituto de Fisica, Universidade Federal Fluminense, Av. Litoranea s/n, Gragoata, Niteroi, R.J., 24210-340 (Brazil); Capurro, O. A.; Marti, G. V. [Laboratorio TANDAR, Comision Nacional de Energia Atomica, Av. General Paz 1499, 1650 San Martin, Buenos Aires (Argentina); Arazi, A.; Figueira, J. M.; Heimann, D. Martinez; Negri, A. E.; Pacheco, A. J. [Laboratorio TANDAR, Comision Nacional de Energia Atomica, Av. General Paz 1499, 1650 San Martin, Buenos Aires (Argentina); CONICET, Av. Rivadavia 1917, Buenos Aires (1033) (Argentina); Niello, J. O. Fernandez [Laboratorio TANDAR, Comision Nacional de Energia Atomica, Av. General Paz 1499, 1650 San Martin, Buenos Aires (Argentina); CONICET, Av. Rivadavia 1917, Buenos Aires (1033) (Argentina); Escuela de Ciencia y Tecnologia, Univ. Nac. de San Martin, San Martin (1650), Buenos Aires (Argentina); Guimaraes, V. [Instituto de Fisica, Universidade de Sao Paulo, Caixa postal 66318, 05315-970, Sao Paulo, S.P. (Brazil)

2009-01-15

432

New analytical potential energy function for doubly charged diatomic molecules  

NASA Astrophysics Data System (ADS)

A new analytical potential function for doubly charged diatomic ions is proposed as V(R) = (?n = 0kanRn-1)exp(-ak+1R)+C/R, where an, ak+1 and C are parameters and R is the nuclear distance. This function can be used to describe the potential curves for doubly charged diatomic ions with both potential minimum and maximum, or without any stationary point. As examples, potential functions of this form for ground states of BH2+, He22+ and HF2+ have been derived. The calculations using the theoretical method QCISD with basis set 6-311++Gast have shown that the potential minimum of BH2+is at Rmin=0.147nm, the maximum at Rmax=0.185nm and ?E = Emax-Emin=0.062 eV; for He22+ Rmin=0.0736nm, Rmax=0.105nm and ?E = Emax-Emin=0.71 eV. It is found that the potential curve for HF2+ is one with a singly repulsive branch. The force constants and spectroscopic data for BH2+ and He22+ have also been worked out.

Wang, Fan-Hou; Yang, Chuan-Lu; Zhu, Zheng-He; Jing, Fu-Qian

2005-02-01

433

Complex absorbing potential based equation-of-motion coupled cluster method for the potential energy curve of CO2- anion  

NASA Astrophysics Data System (ADS)

The equation-of-motion coupled cluster method employing the complex absorbing potential has been used to investigate the low energy electron scattering by CO2. We have studied the potential energy curve for the 2?u resonance states of CO2- upon bending as well as symmetric and asymmetric stretching of the molecule. Specifically, we have stretched the C-O bond length from 1.1 Å to 1.5 Å and the bending angles are changed between 180° and 132°. Upon bending, the low energy 2?u resonance state is split into two components, i.e., 2A1, 2B1 due to the Renner-Teller effect, which behave differently as the molecule is bent.

Ghosh, Aryya; Vaval, Nayana; Pal, Sourav; Bartlett, Rodney J.

2014-10-01

434

Energy Analysis of a Kraft Pulp Mill: Potential for Energy Efficiency and Advanced Biomass Cogeneration  

E-print Network

-pressure steam turbine. Higher electricity to heat ratios is an industry wide trend and anticipated at the mill. The potential for self-sufficiency in energy using only black liquor and bark available on-site is assessed based on the analysis of the present... for the mill. The cogeneration analysis considers conventional steam turhine cycles and hlack liquor and hiomass integrated gasification/gas turhine com hi ned cycles. MILL DESCRIPTION The mill produces an annual average of 790 air dry short tons (ADST...

Subbiah, A.; Nilsson, L. J.; Larson, E. D.

435

Microscopic Calculation of IBM Parameters by Potential Energy Surface Mapping  

E-print Network

A coherent state technique is used to generate an Interacting Boson Model (IBM) Hamiltonian energy surface that simulates a mean field energy surface. The method presented here has some significant advantages over previous work. Specifically, that this can be a completely predictive requiring no a priori knowledge of the IBM parameters. The technique allows for the prediction of the low lying energy spectra and electromagnetic transition rates which are of astrophysical interest. Results and comparison with experiment are included for krypton, molybdenum, palladium, cadmium, gadolinium, dysprosium and erbium nuclei.

I. Bentley; S. Frauendorf

2011-02-08

436

Microscopic Calculation of IBM Parameters by Potential Energy Surface Mapping  

E-print Network

A coherent state technique is used to generate an Interacting Boson Model (IBM) Hamiltonian energy surface that simulates a mean field energy surface. The method presented here has some significant advantages over previous work. Specifically, that this can be a completely predictive requiring no a priori knowledge of the IBM parameters. The technique allows for the prediction of the low lying energy spectra and electromagnetic transition rates which are of astrophysical interest. Results and comparison with experiment are included for krypton, molybdenum, palladium, cadmium, gadolinium, dysprosium and erbium nuclei.

Bentley, I

2011-01-01

437

Airports offer unrealized potential for alternative energy production.  

PubMed

Scaling up for alternative energy such as solar, wind, and biofuel raises a number of environmental issues, notably changes in land use and adverse effects on wildlife. Airports offer one of the few land uses where reductions in wildlife abundance and habitat quality are necessary and socially acceptable, due to risk of wildlife collisions with aircraft. There are several uncertainties and limitations to establishing alternative energy production at airports, such as ensuring these facilities do not create wildlife attractants or other hazards. However, with careful planning, locating alternative energy projects at airports could help mitigate many of the challenges currently facing policy makers, developers, and conservationists. PMID:22245856

DeVault, Travis L; Belant, Jerrold L; Blackwell, Bradley F; Martin, James A; Schmidt, Jason A; Wes Burger, L; Patterson, James W

2012-03-01

438

Vibration of electro-elastic versus magneto-elastic circular/annular plates using the Chebyshev Ritz method  

NASA Astrophysics Data System (ADS)

The aim of this paper is to analyze three-dimensional free vibration of magneto-elastic/electro-elastic circular/annular plates with different boundary conditions using the Chebyshev-Ritz method, in which a set of duplicate Chebyshev polynomial series multiplied by the boundary function satisfying the boundary conditions are chosen as the trial functions of the displacement components, the electric potential and the magnetic potential. Convergence of the method is checked using various Chebyshev polynomial terms. The effect of geometrical parameters and material properties of magneto-elastic/electro-elastic circular/annular plates on the eigenfrequencies of free vibration is considered.

Dong, C. Y.

2008-10-01

439

An Integrated Assessment of China’s Wind Energy Potential  

E-print Network

Computable general equilibrium (CGE) models seeking to evaluate the impacts of electricity policy face difficulties incorporating detail on the variable nature of renewable energy resources. To improve the accuracy of ...

Zhang, D.

440

The economic potential of producing energy from agricultural biomass  

E-print Network

Agricultural biomass is a substitute for fossil fuels, which could provide a sustained energy feedstock and possibly reduce further accumulations of greenhouse gases. However, these feedstocks currently face a market dominated by low cost fossil...

Jerko, Christine

2012-06-07

441

Energy Savings Potential of Process Control Valve Replacement  

E-print Network

variable pressure drop element in the process piping system. The hydraulic system characteristics are then modified to suit the desired control conditions by throttling the control valve flow area to increase or decrease the pressure drop across... the valve. This control philosophy is very effective, but is implemented by creating an energy loss in the piping system to balance the unnecessary energy being delivered by the constant speed pump. HYDRAULIC SYSTEM ANALYSIS Figure I shows the flow (Q...

Holzenthal, L. Jr.

442

Assessing the potential of renewable energy sources in Turkey  

Microsoft Academic Search

To meet Turkey’s growing energy demand, the installed electric power capacity of 27.8 GW in 2001 has to be doubled by 2010 and increased fourfold by 2020. The difference between Turkey’s total primary energy supply (TPES) of from its own sources and total final consumption (TFC) is projected grow from 1 quad (1.06–2.06) in 1999 to 5.71 quads (2.79–8.5) in

F Evrendilek; C Ertekin

2003-01-01

443

Consequences of converting graded to action potentials upon neural information coding and energy efficiency.  

PubMed

Information is encoded in neural circuits using both graded and action potentials, converting between them within single neurons and successive processing layers. This conversion is accompanied by information loss and a drop in energy efficiency. We investigate the biophysical causes of this loss of information and efficiency by comparing spiking neuron models, containing stochastic voltage-gated Na(+) and K(+) channels, with generator potential and graded potential models lacking voltage-gated Na(+) channels. We identify three causes of information loss in the generator potential that are the by-product of action potential generation: (1) the voltage-gated Na(+) channels necessary for action potential generation increase intrinsic noise and (2) introduce non-linearities, and (3) the finite duration of the action potential creates a 'footprint' in the generator potential that obscures incoming signals. These three processes reduce information rates by ?50% in generator potentials, to ?3 times that of spike trains. Both generator potentials and graded potentials consume almost an order of magnitude less energy per second than spike trains. Because of the lower information rates of generator potentials they are substantially less energy efficient than graded potentials. However, both are an order of magnitude more efficient than spike trains due to the higher energy costs and low information content of spikes, emphasizing that there is a two-fold cost of converting analogue to digital; information loss and cost inflation. PMID:24465197

Sengupta, Biswa; Laughlin, Simon Barry; Niven, Jeremy Edward

2014-01-01

444

Consequences of Converting Graded to Action Potentials upon Neural Information Coding and Energy Efficiency  

PubMed Central

Information is encoded in neural circuits using both graded and action potentials, converting between them within single neurons and successive processing layers. This conversion is accompanied by information loss and a drop in energy efficiency. We investigate the biophysical causes of this loss of information and efficiency by comparing spiking neuron models, containing stochastic voltage-gated Na+ and K+ channels, with generator potential and graded potential models lacking voltage-gated Na+ channels. We identify three causes of information loss in the generator potential that are the by-product of action potential generation: (1) the voltage-gated Na+ channels necessary for action potential generation increase intrinsic noise and (2) introduce non-linearities, and (3) the finite duration of the action potential creates a ‘footprint’ in the generator potential that obscures incoming signals. These three processes reduce information rates by ?50% in generator potentials, to ?3 times that of spike trains. Both generator potentials and graded potentials consume almost an order of magnitude less energy per second than spike trains. Because of the lower information rates of generator potentials they are substantially less energy efficient than graded potentials. However, both are an order of magnitude more efficient than spike trains due to the higher energy costs and low information content of spikes, emphasizing that there is a two-fold cost of converting analogue to digital; information loss and cost inflation. PMID:24465197

Sengupta, Biswa; Laughlin, Simon Barry; Niven, Jeremy Edward

2014-01-01

445

Passive elastic mechanism to mimic fish-muscle action in anguilliform swimming  

PubMed Central

Swimmers in nature use body undulations to generate propulsive and manoeuvring forces. The anguilliform kinematics is driven by muscular actions all along the body, involving a complex temporal and spatial coordination of all the local actuations. Such swimming kinematics can be reproduced artificially, in a simpler way, by using the elasticity of the body passively. Here, we present experiments on self-propelled elastic swimmers at a free surface in the inertial regime. By addressing the fluid–structure interaction problem of anguilliform swimming, we show that our artificial swimmers are well described by coupling a beam theory with the potential flow model of Lighthill. In particular, we show that the propagative nature of the elastic wave producing the propulsive force is strongly dependent on the dissipation of energy along the body of the swimmer. PMID:23985737

Ramananarivo, Sophie; Godoy-Diana, Ramiro; Thiria, Benjamin

2013-01-01

446

Diabatic heating fields and the generation of available potential energy during FGGE  

NASA Technical Reports Server (NTRS)

Global diabatic heating is estimated using fields of directly computed heating components, in particular those due to shortwave radiation, longwave radiation, sensible heating, and latent heating produced every 6 hours. The role of average fields of diabatic heating in the generation of available potential energy is examined. It is observed that latent heating is most significant in generating available potential energy.

Salstein, David A.; Rosen, Richard D.; Baker, Wayman E.; Kalnay, Eugenia

1986-01-01

447

Adiabatic model of $(d,p)$ reactions with explicitly energy-dependent non-local potentials  

E-print Network

We have developed an approximate way of dealing with explicit energy-dependence of non-local nucleon optical potentials as used to predict the $(d,p)$ cross sections within the adiabatic theory. Within this approximation, the non-local optical potentials have to be evaluated at an energy shifted from half the incident deuteron energy by the $n-p$ kinetic energy averaged over the range of the $n-p$ interaction and then treated as an energy-independent non-local potential. Thus the evaluation of the distorting potential in the incident channel is reduced to a problem solved in our previous work in [{\\it Phys. Rev. Lett. 110, 112501(2013) and Phys. Rev. C 87, 064610 (2013)}]. We have demonstrated how our new model works for the case of $^{16}$O$(d,p)^{17}$O, $^{36}$Ar($d,p)^{37}$Ar and $^{40}$Ca$(d,p)^{41}$Ca reactions and highlighted the need for a detailed understanding of energy-dependence of non-local potentials. We have also suggested a simple way of correcting the $d-A$ effective potentials for non-locality when the underlying energy-dependent non-local nucleon potentials are unknown but energy-dependent local phenomenological nucleon potentials are available.

R. C. Johnson; N. K. Timofeyuk

2014-01-14

448

CVRQD ab initio ground-state adiabatic potential energy surfaces for the water molecule  

Microsoft Academic Search

The high accuracy ab initio adiabatic potential energy surfaces (PESs) of the ground electronic state of the water molecule, determined originally by Polyansky et al. [Science 299, 539 (2003)] and called CVRQD, are extended and carefully characterized and analyzed. The CVRQD potential energy surfaces are obtained from extrapolation to the complete basis set of nearly full configuration interaction valence-only electronic

Paolo Barletta; Sergei V. Shirin; Nikolai F. Zobov; Oleg L. Polyansky; Jonathan Tennyson; Edward F. Valeev; Attila G. Császár

2006-01-01

449

Long-Wavelength Elastic Interactions in Complex Crystals  

NASA Astrophysics Data System (ADS)

The long-wavelength (LWL) limit of the elastic interactions in complex non-Bravais lattices is investigated on the basis of microscopic elasticity theory. The conceptual simplicity of our approach enables large-scale simulations in materials with complex crystalline structures. We demonstrate the method by calculating the LWL elastic energy of hcp-based dilute Mg alloys for a variety of impurities. Our results show that for large coherent precipitates, the strain-induced interactions control the shape along the hexagonal axis whereas the surface energy dictates the basal growth. Our method allows a straightforward treatment of the long-range elastic interactions in the cluster expansion method for complex crystals.

Diaz Ortiz, Alejandro; Kurta, Ruslan; Bugaev, Volodymyr

2010-03-01

450

High-energy behavior of the nuclear symmetry potential in asymmetric nuclear matter  

E-print Network

Using the relativistic impulse approximation with empirical NN scattering amplitude and the nuclear scalar and vector densities from the relativistic mean-field theory, we evaluate the Dirac optical potential for neutrons and protons in asymmetric nuclear matter. From the resulting Schr\\"{o}% dinger-equivalent potential, the high energy behavior of the nuclear symmetry potential is studied. We find that the symmetry potential at fixed baryon density is essentially constant once the nucleon kinetic energy is greater than about 500 MeV. Moreover, for such high energy nucleon, the symmetry potential is slightly negative below a baryon density of about $% \\rho =0.22$ fm$^{-3}$ and then increases almost linearly to positive values at high densities. Our results thus provide an important constraint on the energy and density dependence of nuclear symmetry potential in asymmetric nuclear matter.

Lie-Wen Chen; Che Ming Ko; Bao-An Li

2005-08-24

451

Examining student ability to interpret and use potential energy diagrams for classical systems  

NSDL National Science Digital Library

The Physics Education Group at the University of Washington is examining the extent to which students are able to use graphs of potential energy vs. position to infer kinematic and dynamic quantities for a system. The findings indicate that many students have difficulty in relating the graphs to real-world systems. Some problems seem to be graphical in nature (e.g., interpreting graphs of potential energy vs. position as graphs of position vs. time)