While these samples are representative of the content of Science.gov,

they are not comprehensive nor are they the most current set.

We encourage you to perform a real-time search of Science.gov

to obtain the most current and comprehensive results.

Last update: August 15, 2014.

1

Impact of 120-W 2-?m continuous wave laser vapoenucleation of the prostate on sexual function.

The objective of this work is to evaluate the impact of 120-W 2-?m continuous wave (cw) laser vapoenucleation of the prostate in patients with benign prostatic hyperplasia (BPH) on sexual function. One hundred twenty-two consecutive patients with BPH were retrospectively collected in this study and were classified into two groups for surgical treatment with 2-?m cw laser vapoenucleation or transurethral resection of the prostate (TURP). International Index of Erectile Function (IIEF) and general assessment questions were completed before and 12 months after treatment to determine the impact on sexual function. A total of 33 patients (52.4%) in group 1 and 31 (52.5%) in group 2 reported various degrees of erectile dysfunction before surgery. Interestingly, an increase in IIEF-EF score by 2 points was reported by 16 (25.4%) and 14 (23.7%) patients, respectively, and mean EF score did show a marginal but not significant increase postoperatively in both group. Differences about orgasmic intercourse satisfaction, sexual desire domain, and overall satisfaction scores in each group were not significant between preoperative and postoperative, but there was a significant decrease in the orgasmic function domain score at 12 months postoperation in both groups (p?impact on sexual function. No significant erectile function improvement was observed after surgery, but these two techniques significantly lowered the IIEF orgasmic function domain and this was mainly caused by retrograde ejaculation. PMID:23828495

Wang, Yubin; Shao, Jinkai; Lu, Yongning; Lü, Yongan; Li, Xiaodong

2014-03-01

2

NSDL National Science Digital Library

The Ejs Wave Function Plotter model displays a one-dimensional wave function u(x,t) depicting a disturbance at position x and time t. The disturbance can be mass density, pressure, or electric field depending on the physical context. The default wave function is sinusoidal but any other analytic function can be entered in the text box. The number of sampling points can also be changed. You can modify this simulation if you have Ejs installed by right-clicking within the plot and selecting âOpen Ejs Modelâ from the pop-up menu item. Ejs Wave Function Plotter model was created using the Easy Java Simulations (Ejs) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_osc_chains_WaveFunctionPlotter.jar file will run the program if Java is installed. Ejs is a part of the Open Source Physics Project and is designed to make it easier to access, modify, and generate computer models. Additional Ejs models for Newtonian mechanics are available. They can be found by searching ComPADRE for Open Source Physics, OSP, or Ejs.

Christian, Wolfgang

2008-07-05

3

NASA Astrophysics Data System (ADS)

The framework of ab initio density-functional theory (DFT) has been introduced as a way to provide a seamless connection between the Kohn-Sham (KS) formulation of DFT and wave-function based ab initio approaches [R. J. Bartlett, I. Grabowski, S. Hirata, and S. Ivanov, J. Chem. Phys. 122, 034104 (2005)]. Recently, an analysis of the impact of dynamical correlation effects on the density of the neon atom was presented [K. Jankowski, K. Nowakowski, I. Grabowski, and J. Wasilewski, J. Chem. Phys. 130, 164102 (2009)], contrasting the behaviour for a variety of standard density functionals with that of ab initio approaches based on second-order Møller-Plesset (MP2) and coupled cluster theories at the singles-doubles (CCSD) and singles-doubles perturbative triples [CCSD(T)] levels. In the present work, we consider ab initio density functionals based on second-order many-body perturbation theory and coupled cluster perturbation theory in a similar manner, for a range of small atomic and molecular systems. For comparison, we also consider results obtained from MP2, CCSD, and CCSD(T) calculations. In addition to this density based analysis, we determine the KS correlation potentials corresponding to these densities and compare them with those obtained for a range of ab initio density functionals via the optimized effective potential method. The correlation energies, densities, and potentials calculated using ab initio DFT display a similar systematic behaviour to those derived from electronic densities calculated using ab initio wave function theories. In contrast, typical explicit density functionals for the correlation energy, such as VWN5 and LYP, do not show behaviour consistent with this picture of dynamical correlation, although they may provide some degree of correction for already erroneous explicitly density-dependent exchange-only functionals. The results presented here using orbital dependent ab initio density functionals show that they provide a treatment of exchange and correlation contributions within the KS framework that is more consistent with traditional ab initio wave function based methods.

Grabowski, Ireneusz; Teale, Andrew M.; ?miga, Szymon; Bartlett, Rodney J.

2011-09-01

4

The framework of ab initio density-functional theory (DFT) has been introduced as a way to provide a seamless connection between the Kohn-Sham (KS) formulation of DFT and wave-function based ab initio approaches [R. J. Bartlett, I. Grabowski, S. Hirata, and S. Ivanov, J. Chem. Phys. 122, 034104 (2005)]. Recently, an analysis of the impact of dynamical correlation effects on the density of the neon atom was presented [K. Jankowski, K. Nowakowski, I. Grabowski, and J. Wasilewski, J. Chem. Phys. 130, 164102 (2009)], contrasting the behaviour for a variety of standard density functionals with that of ab initio approaches based on second-order Møller-Plesset (MP2) and coupled cluster theories at the singles-doubles (CCSD) and singles-doubles perturbative triples [CCSD(T)] levels. In the present work, we consider ab initio density functionals based on second-order many-body perturbation theory and coupled cluster perturbation theory in a similar manner, for a range of small atomic and molecular systems. For comparison, we also consider results obtained from MP2, CCSD, and CCSD(T) calculations. In addition to this density based analysis, we determine the KS correlation potentials corresponding to these densities and compare them with those obtained for a range of ab initio density functionals via the optimized effective potential method. The correlation energies, densities, and potentials calculated using ab initio DFT display a similar systematic behaviour to those derived from electronic densities calculated using ab initio wave function theories. In contrast, typical explicit density functionals for the correlation energy, such as VWN5 and LYP, do not show behaviour consistent with this picture of dynamical correlation, although they may provide some degree of correction for already erroneous explicitly density-dependent exchange-only functionals. The results presented here using orbital dependent ab initio density functionals show that they provide a treatment of exchange and correlation contributions within the KS framework that is more consistent with traditional ab initio wave function based methods. PMID:21950854

Grabowski, Ireneusz; Teale, Andrew M; ?miga, Szymon; Bartlett, Rodney J

2011-09-21

5

Vortices in Atomic Wave Functions

Vortices in atomic wave functions are shown to have observable consequences. It is shown that time-dependent electron wave functions in coordinate space go over to electron emission amplitudes in the limit that time becomes infinite. This relation between wave functions and emission amplitudes is called the imaging theorem. According to this theorem vortices in wave functions at small times when particles interact in a complex way appear as vortices in electron momentum distributions where they produce observable features. Conversely, some observable structures may be interpreted in terms of vortices no matter how they are seen or computed. We verify that previously unexplained features in (e,2e) triply differential cross sections can be interpreted in terms of vortices.

Macek, Joseph H [ORNL

2010-01-01

6

Analysis of superoscillatory wave functions

Surprisingly, differentiable functions are able to oscillate arbitrarily faster than their highest Fourier component would suggest. The phenomenon is called superoscillation. Recently, a practical method for calculating superoscillatory functions was presented and it was shown that superoscillatory quantum mechanical wave functions should exhibit a number of counter-intuitive physical effects. Following up on this work, we here present more general methods

Matt S. Calder; Achim Kempf

2005-01-01

7

If it is possible to describe the state of an atom by the addition of several vectors, and if one assumes the wave function for any state of a configuration to be a linear combination of product functions for that configuration, then one can determine the coefficients in the linear combination by a simple method. Examples are given. The usual

James H. Bartlett

1931-01-01

8

Correlated electronic wave functions: Correlated and transcorrelated wave functions

The development of the transcorrelated Hamiltonian method (THM) by Boys and Handy seemed to imply that the determination of atomic and molecular wave functions and energies with full electronic correlation can be done with calculations which involve at worst only pseudo-six-dimensional integrals. We show that the THM equations of Boys and Handy are in fact only the first of a

M. W. C. Dharma-Wardana; François Grimaldi

1976-01-01

9

Expansion of Continuum Functions on Resonance Wave Functions and Amplitudes.

National Technical Information Service (NTIS)

To overcome difficulties encountered with wave functions of continuum spectrum (for example, in a shell model with continuum) the pole expansion (by the Mittag-Leffler theorem) of wave functions, scattering amplitudes and the Green functions with positive...

J. Bang F. A. Gareev M. H. Gizzatkulov S. A. Goncharov

1978-01-01

10

Meson wave function from holographic approaches

We discuss the light-front wave function for the valence quark state of mesons using the AdS/CFT correspondence. We consider two kinds of wave functions obtained in different holographic Soft-Wall approaches.

Vega, Alfredo; Schmidt, Ivan [Departamento de Fisica y Centro de Estudios Subatomicos, Universidad Tecnica Federico Santa Maria, Casilla 110-V, Valparaiso (Chile); Branz, Tanja; Gutsche, Thomas; Lyubovitskij, Valery E. [Institut fuer Theoretische Physik, Universitaet Tuebingen, Kepler Center for Astro and Particle Physics, Auf der Morgenstelle 14, D-72076 Tuebingen (Germany)

2010-08-04

11

The destructive impact of the rogue waves

NASA Astrophysics Data System (ADS)

In our talk rogue waves at the ocean will be considered. By means of numerical modeling dangerous impact of rogue waves on the ships and oil rigs is calculated. Cases when these waves can bring in accident are considered. Using statistics of emergence of waves (see [1]-[2]), it is possible to estimate risks in each case. These results can be used for safety of the ships and oil rigs from rogue waves. References [1] V.E. Zakharov, A.I. Dyachenko, R.V. Shamin. How probability for freak wave formation can be found // THE EUROPEAN PHYSICAL JOURNAL - SPECIAL TOPICS Volume 185, Number 1, 113-124, DOI: 10.1140/epjst/e2010-01242-y [2] V.E. Zakharov, R.V. Shamin. Statistics of rogue waves in computer experiments // JETP Letters, 2012, V. 96, Issue 1, pp 66-69.

Shamin, Roman

2013-04-01

12

Precanonical quantization and the Schrödinger wave functional

A relation between the Schrödinger wave functional and the Clifford-valued wave function which appears in what we call precanonical quantization of fields and fulfills a Dirac-like generalized covariant Schrödinger equation on the space of field and space-time variables is discussed. The Schrödinger wave functional is argued to be the trace of the positive frequency part of the continual product over

Igor V. Kanatchikov

2001-01-01

13

Meson wave function from holographic models

We consider the light-front wave function for the valence quark state of mesons using the AdS/CFT correspondence, as has been suggested by Brodsky and Teramond. Two kinds of wave functions, obtained in different holographic Soft-Wall models, are discussed.

Vega, Alfredo; Schmidt, Ivan [Departamento de Fisica y Centro de Estudios Subatomicos, Universidad Tecnica Federico Santa Maria, Casilla 110-V, Valparaiso (Chile); Branz, Tanja; Gutsche, Thomas; Lyubovitskij, Valery E. [Institut fuer Theoretische Physik, Universitaet Tuebingen, Kepler Center for Astro and Particle Physics, Auf der Morgenstelle 14, D-72076 Tuebingen (Germany)

2009-09-01

14

Electron Wave Functions in Metallic Potassium

Wave functions to order k2 are presented for electrons in metallic potassium. The calculation is an application of the cellular method. The potential was derived from a self-consistent field and contains exchange effects.

Joseph Callaway

1960-01-01

15

Designing electron wave functions in assembled nanostructures

We use the scanning tunneling microscope to not only to map electron wave functions but also to engineer them. By assembling nanostructures from individual atoms and molecules, we confine two-dimensional electronic states into closed electron resonators, or \\

Christopher Ryan Moon

2009-01-01

16

Electronic Wave Functions for Polyatomic Molecules

A one-electron basis set made from functions with exponential and Gaussian radial dependence is proposed for constructing many-electron, many-center, electronic wave functions. Appropriate mixtures of these two types may greatly simplify the evaluation of many-center, two electron integrals and in addition make possible an improved description of the molecular bond. Plane waves may also be added to the basis set

Leland C. Allen

1959-01-01

17

The Wave Function and Quantum Reality

We investigate the meaning of the wave function by analyzing the mass and charge density distributions of a quantum system. According to protective measurement, a charged quantum system has effective mass and charge density distributing in space, proportional to the square of the absolute value of its wave function. In a realistic interpretation, the wave function of a quantum system can be taken as a description of either a physical field or the ergodic motion of a particle. The essential difference between a field and the ergodic motion of a particle lies in the property of simultaneity; a field exists throughout space simultaneously, whereas the ergodic motion of a particle exists throughout space in a time-divided way. If the wave function is a physical field, then the mass and charge density will be distributed in space simultaneously for a charged quantum system, and thus there will exist gravitational and electrostatic self-interactions of its wave function. This not only violates the superposition principle of quantum mechanics but also contradicts experimental observations. Thus the wave function cannot be a description of a physical field but be a description of the ergodic motion of a particle. For the later there is only a localized particle with mass and charge at every instant, and thus there will not exist any self-interaction for the wave function. It is further argued that the classical ergodic models, which assume continuous motion of particles, cannot be consistent with quantum mechanics. Based on the negative result, we suggest that the wave function is a description of the quantum motion of particles, which is random and discontinuous in nature. On this interpretation, the square of the absolute value of the wave function not only gives the probability of the particle being found in certain locations, but also gives the probability of the particle being there. The suggested new interpretation of the wave function provides a natural realistic alternative to the orthodox interpretation, and it also implies that the de Broglie-Bohm theory and many-worlds interpretation are wrong and the dynamical collapse theories are in the right direction by admitting wavefunction collapse.

Gao Shan [Unit for History and Philosophy of Science and Centre for Time, SOPHI, University of Sydney, Sydney, NSW 2006 (Australia)

2011-03-28

18

Functional methods for waves in random media

NASA Technical Reports Server (NTRS)

Some basic ideas in functional methods for waves in random media are illustrated through a simple random differential equation. These methods are then generalized to solve certain random parabolic equations via an exponential representation given by the Feynman-Kac formula. It is shown that these functional methods are applicable to a number of problems in random wave propagation. They include the forward-scattering approximation in Gaussian white-noise media; the solution of the optical beam propagation problem by a phase-integral method; the high-frequency scattering by bounded random media; and a derivation of approximate moment equations from the functional integral representation.

Chow, P. L.

1981-01-01

19

Functional methods for waves in random media

NASA Technical Reports Server (NTRS)

Some basic ideas in functional methods for waves in random media are illustrated through a simple random differential equation. These methods are then generalized to solve certain random parabolic equations via an exponential representation given by the Feynman-Kac formula. It is shown that these functional methods are applicable to a number of problems in random wave propagation. They include the forward-scattering approximation in Gaussian white-noise media; the solution of the optical beam propagation problem by a phase-integral method; the high-frequency scattering by bounded random media, and a derivation of approximate moment equations from the functional integral representation.

Chow, P. L.

1981-01-01

20

Pairing phase transitions in nuclear wave functions

The exact solution of the nuclear shell model is used for studying the phase transition from superfluid to normal Fermi-liquid as a function of the pairing strength, excitation energy (or temperature), nuclear spin and the presence of other types of residual interactions. The phase transition in a finite system is seen through the change of properties of individual wave functions.

Horoi, Mihai [Department of Physics, Central Michigan University, Mount Pleasant, Michigan 48859 (United States); Zelevinsky, Vladimir [Department of Physics and Astronomy and National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824-1321 (United States)

2007-05-15

21

New microscopic wave function of ?-condensation

NASA Astrophysics Data System (ADS)

We explain how to treat a microscopic wave function of ?-condensation taking a 3 ?-nucleus as a typical example. The wave function has been originally proposed ten years before by Horiuchi, Röpke, Schuck and the present author (Phys. Rev. Lett., 2001, 87: 192501). The microscopic model, which fully takes into account the Pauli principle between all the constituent nucleons, effective internucleon forces and the Coulomb force, can play an important role in reproducing an ?-gas nature thanks to ?-condensation as an excited state of ?-like nuclei. An essential point of the wave function is to describe their ground state simultaneously. We study its typical features by giving an analytical formula of the norm kernel and the kernel concerning the one-body operator for 3 ?-condensation.

Tohsaki, Akihiro

2011-09-01

22

Spectroscopic measurement of an atomic wave function

We present a simple spectroscopic method based on Autler-Townes spectroscopy to determine the center-of-mass atomic wave function. The detection of spontaneously emitted photons from a three-level atom, in which two upper levels are driven by a classical standing light, yields information about the position and momentum distribution of the atom [A. M. Herkommer, W. P. Schleich, and M. S. Zubairy, J. Mod. Opt. 44, 2507 (1997)]. In this paper, we show that both the amplitude and phase information of the center-of-mass atomic wave function can be obtained from these distributions after a series of conditional measurements on the atom and the emitted photon.

Kapale, Kishore T. [Institute for Quantum Studies, and Department of Physics, Texas A and M University, College Station, Texas 77843-4242 (United States); Qamar, Shahid [Institute for Quantum Studies, and Department of Physics, Texas A and M University, College Station, Texas 77843-4242 (United States); Department of Physics and Applied Mathematics, Pakistan Institute of Engineering and Applied Science, Nilore, Islamabad (Pakistan); Zubairy, M. Suhail [Institute for Quantum Studies, and Department of Physics, Texas A and M University, College Station, Texas 77843-4242 (United States); Department of Electronics, Quaid-i-Azam University, Islamabad (Pakistan)

2003-02-01

23

Process characterization with Monte Carlo wave functions

NASA Astrophysics Data System (ADS)

We present an efficient method to simulate a quantum process subject to dissipation and noise. To describe the effect on any input state we evolve Monte Carlo wave functions for a principal and ancilla system, prepared initially in an entangled state. In analogy to experimental process tomography, the simulated propagator for the system density matrix is conveniently described by a process ? matrix - directly determined from the stochastic state vectors. Our method significantly reduces the computational complexity compared with standard theoretical characterization methods. It also delivers an upper bound on the trace distance between the ideal and simulated process based on the evolution of only a single wave function of the entangled system.

Gulliksen, J.; Rao, D. D. Bhaktavatsala; Mølmer, K.

2013-11-01

24

Semiclassical wave functions for open quantum billiards.

We present a semiclassical approximation to the scattering wave function ?(r,k) for an open quantum billiard, which is based on the reconstruction of the Feynman path integral. We demonstrate its remarkable numerical accuracy for the open rectangular billiard and show that the convergence of the semiclassical wave function to the full quantum state is controlled by the mean path length or equivalently the dwell time for a given scattering state. In the numerical implementation a cutoff length in the maximum path length or, equivalently, a maximum dwell time ?(max) included implies a finite energy resolution ?E~?(max)(-1). Possible applications include leaky billiards and systems with decoherence present. PMID:24032910

Lackner, Fabian; B?ezinová, Iva; Burgdörfer, Joachim; Libisch, Florian

2013-08-01

25

Semiclassical wave functions for open quantum billiards

NASA Astrophysics Data System (ADS)

We present a semiclassical approximation to the scattering wave function ?(r,k) for an open quantum billiard, which is based on the reconstruction of the Feynman path integral. We demonstrate its remarkable numerical accuracy for the open rectangular billiard and show that the convergence of the semiclassical wave function to the full quantum state is controlled by the mean path length or equivalently the dwell time for a given scattering state. In the numerical implementation a cutoff length in the maximum path length or, equivalently, a maximum dwell time ?max included implies a finite energy resolution ?E˜?max-1. Possible applications include leaky billiards and systems with decoherence present.

Lackner, Fabian; B?ezinová, Iva; Burgdörfer, Joachim; Libisch, Florian

2013-08-01

26

The influence of air and scale on wave impact pressures

Both laboratory and field tests that are described provide new information on the characteristics of wave impacts. Laboratory drop tests conducted using seawater and freshwater demonstrate that maximum impact pressures and rise times are influenced by both the level of aeration and the violence of the impact. A relationship is derived which enables the reduction in impact pressure caused by

G. N. Bullock; A. R. Crawford; P. J. Henson; M. J. A. Walkden; P. A. D. Bird

2001-01-01

27

Multifractal wave functions of simple quantum maps.

We study numerically multifractal properties of two models of one-dimensional quantum maps: a map with pseudointegrable dynamics and intermediate spectral statistics and a map with an Anderson-like transition recently implemented with cold atoms. Using extensive numerical simulations, we compute the multifractal exponents of quantum wave functions and study their properties, with the help of two different numerical methods used for classical multifractal systems (box-counting and wavelet methods). We compare the results of the two methods over a wide range of values. We show that the wave functions of the Anderson map display a multifractal behavior similar to eigenfunctions of the three-dimensional Anderson transition but of a weaker type. Wave functions of the intermediate map share some common properties with eigenfunctions at the Anderson transition (two sets of multifractal exponents, with similar asymptotic behavior), but other properties are markedly different (large linear regime for multifractal exponents even for strong multifractality, different distributions of moments of wave functions, and absence of symmetry of the exponents). Our results thus indicate that the intermediate map presents original properties, different from certain characteristics of the Anderson transition derived from the nonlinear sigma model. We also discuss the importance of finite-size effects. PMID:21230364

Martin, John; García-Mata, Ignacio; Giraud, Olivier; Georgeot, Bertrand

2010-10-01

28

Multifractal wave functions of simple quantum maps

NASA Astrophysics Data System (ADS)

We study numerically multifractal properties of two models of one-dimensional quantum maps: a map with pseudointegrable dynamics and intermediate spectral statistics and a map with an Anderson-like transition recently implemented with cold atoms. Using extensive numerical simulations, we compute the multifractal exponents of quantum wave functions and study their properties, with the help of two different numerical methods used for classical multifractal systems (box-counting and wavelet methods). We compare the results of the two methods over a wide range of values. We show that the wave functions of the Anderson map display a multifractal behavior similar to eigenfunctions of the three-dimensional Anderson transition but of a weaker type. Wave functions of the intermediate map share some common properties with eigenfunctions at the Anderson transition (two sets of multifractal exponents, with similar asymptotic behavior), but other properties are markedly different (large linear regime for multifractal exponents even for strong multifractality, different distributions of moments of wave functions, and absence of symmetry of the exponents). Our results thus indicate that the intermediate map presents original properties, different from certain characteristics of the Anderson transition derived from the nonlinear sigma model. We also discuss the importance of finite-size effects.

Martin, John; García-Mata, Ignacio; Giraud, Olivier; Georgeot, Bertrand

2010-10-01

29

Impact detection using ultrasonic waves based on artificial immune system

NASA Astrophysics Data System (ADS)

This paper presents a structural health monitoring system for judging structural condition of metallic plates by analyzing ultrasonic waves. Many critical accidents of structures like buildings and aircrafts are caused by small structural errors; cracks and loosened bolts etc. This is a reason why we need to detect little errors at an early stage. Moreover, to improve precision and to reduce cost for damage detection, it is necessary to build and update the database corresponding to environmental change. This study focuses our attention on the automatable structures, specifically, applying artificial immune system (AIS) algorithm to determine the structure safe or not. The AIS is a novelty computational detection algorithm inspired from biological defense system, which discriminates between self and non-self to reject nonself cells. Here, self is defined to be normal data patterns and non-self is abnormal data patterns. Furthermore, it is not only pattern recognition but also it has a storage function. In this study, a number of impact resistance experiments of duralumin plates, with normal structural condition and abnormal structural condition, are examined and ultrasonic waves are acquired by AE sensors on the surface of the aluminum plates. By accumulating several feature vectors of ultrasonic waves, a judging method, which can determine an abnormal wave as nonself, inspired from immune system is created. The results of the experiments show good performance of this method.

Okamoto, Keisuke; Mita, Akira

2009-03-01

30

Wave function microscopy of quasibound atomic states.

In the 1980s Demkov, Kondratovich, and Ostrovsky and Kondratovich and Ostrovsky proposed an experiment based on the projection of slow electrons emitted by a photoionized atom onto a position-sensitive detector. In the case of resonant excitation, they predicted that the spatial electron distribution on the detector should represent nothing else but a magnified image of the projection of a quasibound electronic state. By exciting lithium atoms in the presence of a static electric field, we present in this Letter the first experimental photoionization wave function microscopy images where signatures of quasibound states are evident. Characteristic resonant features, such as (i) the abrupt change of the number of wave function nodes across a resonance and (ii) the broadening of the outer ring of the image (associated with tunneling ionization), are observed and interpreted via wave packet propagation simulations and recently proposed resonance tunneling mechanisms. The electron spatial distribution measured by our microscope is a direct macroscopic image of the projection of the microscopic squared modulus of the electron wave that is quasibound to the atom and constitutes the first experimental realization of the experiment proposed 30 years ago. PMID:23683194

Cohen, S; Harb, M M; Ollagnier, A; Robicheaux, F; Vrakking, M J J; Barillot, T; Lépine, F; Bordas, C

2013-05-01

31

Wave Function Microscopy of Quasibound Atomic States

NASA Astrophysics Data System (ADS)

In the 1980s Demkov, Kondratovich, and Ostrovsky and Kondratovich and Ostrovsky proposed an experiment based on the projection of slow electrons emitted by a photoionized atom onto a position-sensitive detector. In the case of resonant excitation, they predicted that the spatial electron distribution on the detector should represent nothing else but a magnified image of the projection of a quasibound electronic state. By exciting lithium atoms in the presence of a static electric field, we present in this Letter the first experimental photoionization wave function microscopy images where signatures of quasibound states are evident. Characteristic resonant features, such as (i) the abrupt change of the number of wave function nodes across a resonance and (ii) the broadening of the outer ring of the image (associated with tunneling ionization), are observed and interpreted via wave packet propagation simulations and recently proposed resonance tunneling mechanisms. The electron spatial distribution measured by our microscope is a direct macroscopic image of the projection of the microscopic squared modulus of the electron wave that is quasibound to the atom and constitutes the first experimental realization of the experiment proposed 30 years ago.

Cohen, S.; Harb, M. M.; Ollagnier, A.; Robicheaux, F.; Vrakking, M. J. J.; Barillot, T.; Lépine, F.; Bordas, C.

2013-05-01

32

Arterial stiffness is correlated with left ventricular (LV) diastolic function as well as susceptibility to LV systolic function. Therefore, if LV systolic function is not known, the relationship between arterial stiffness and LV diastolic function is difficult to determine. A total of 260 patients were included in the study. The brachial-ankle pulse wave velocity (baPWV) and the ratio of right

Po-Chao Hsu; Tsung-Hsien Lin; Chee-Siong Lee; Chun-Yuan Chu; Ho-Ming Su; Wen-Chol Voon; Wen-Ter Lai; Sheng-Hsiung Sheu; H-M Su

2011-01-01

33

Microscopic Wave Function of Alpha Condensation

NASA Astrophysics Data System (ADS)

We explain how to treat a microscopic wave function of ?-condensation named THSR taking 3?-condensation as a typical example. The microscopic model, which fully takes into account the Pauli principle between all the constituent nucleons and effective inter-nucleon forces simultaneously, can play an important role in reproducing an ?-gas-like nature thanks to ?-condensation. We study its typical features by giving numerical results of the norm kernel for 3?-condensation.

Tohsaki, Akihiro; Funaki, Yasuro; Horiuchi, Hisashi; Röpke, Gerd; Schuck, Peter; Yamada, Taiichi

34

Impact Induced Surface Wave Propagation In Concrete Massif

NASA Astrophysics Data System (ADS)

Experimental inspection of large concrete massifs was carried out. The concrete massif was excited by the light impact of metallic road, falling from the height 50 cm. The most energy (60-70)% from that impact goes for surface wave excitation in concrete. They are vertical polarized Relay waves, propagating in concrete, deeps till (0, 5 - 0, 7) ?, where ? is wave length of excited oscillations. Wave frequencies from the impact source in object under research are 2-4 kHz; they are frequencies of acoustic emission (AE) of moving metal about grainy surface. The mechanism of low-frequency acoustic emission in grainy materials is known as f = V/d, (V velocity of displacement [m/s] divide to length of displacement, [m]. In granular materials the diameter of grain is the determine length of displacement, That is simple, convenient nondestructive method for Relay wave excitation for inspection and monitoring of large surfaces of granular materials. Propagation of shock-induced surface wave for the distance of 50 m is observed. The velocity of propagation of vertically polarized Raleigh waves reflects the fractures inside the concrete body-the smaller is the wave velocity, the higher is the crack concentration. It speaks nonlinearity of surface wave propagation. Assessment of surface wave propagation velocity V and Q-factor sensitivity to structural changes is made. Q-Factor sensitivity is higher and applicability wider than that for surface waves.

Vilchinska, Nora A.

2008-06-01

35

Wave function methods for fractional electrons.

Determining accurate chemical potentials is of considerable interest in various chemical and physical contexts: from small molecular charge-transfer complexes to bandgap in bulk materials such as semi-conductors. Chemical potentials are typically evaluated either by density functional theory, or, alternatively, by computationally more intensive Greens function based GW computations. To calculate chemical potentials, the ground state energy needs to be defined for fractional charges. We thus explore an extension of wave function theories to fractional charges, and investigate the ionization potential and electron affinity as the derivatives of the energy with respect to the electron number. The ultimate aim is to access the chemical potential of correlated wave function methods without the need of explicitly changing the numbers of electrons, making the approach readily applicable to bulk materials. We find that even though second order perturbation theory reduces the fractional charge error considerably compared to Hartree-Fock and standard density functionals, higher order perturbation theory is more accurate and coupled-cluster approaches are even more robust, provided the electrons are bound at the Hartree-Fock level. The success of post-HF approaches to improve over HF relies on two equally important aspects: the integer values are more accurate and the Coulomb correlation between the fractionally occupied orbital and all others improves the straight line behavior significantly as identified by a correction to Hartree-Fock. Our description of fractional electrons is also applicable to fractional spins, illustrating the ability of coupled-cluster singles and doubles to deal with two degenerate fractionally occupied orbitals, but its inadequacy for three and more fractional spins, which occur, for instance, for spherical atoms and when dissociating double bonds. Our approach explores the realm of typical wave function methods that are applied mostly in molecular chemistry, but become available to the solid state community and offer the advantage of an integrated approach: fundamental gap, relative energies, and optimal geometries can be obtained at the same level. PMID:23968072

Steinmann, Stephan N; Yang, Weitao

2013-08-21

36

Impact of shear and curvature on surface gravity wave stress

NASA Astrophysics Data System (ADS)

It has been shown that surface gravity wave stress is sensitive to the low level wind profile shape. The simplest way of incorporating those effects in a theoretical model has been recently proposed, using a second order WKB approach, which leads to closed analytical formulae for the surface stress as a function of stability, low level wind and its two first derivatives (shear and curvature). In the present study, we assess the impact of those calculations on global scale gravity wave stress and the corresponding torque, using 6-hourly data from ERA-40 reanalysis, at full resolution. While the theory shows that linear wind shear leads to a reduced stress and curvature may lead to stress enhancement, the present results indicate that the latter effect is dominant. However, when one looks for regionally integrated stress fields for the large mountain ranges, where cancellation effects take place thorough time and space integration, the overall effect is one of drag enhancement in regions of dominant easterly flow, namely Antarctica and East Africa, leading to a slight reduction of the global westerly torque due to mountain waves. Drag enhancement due to wind profile curvature seems to be an important effect in Antarctic flow, where it accounts for a 50% increase in the mean regional torque, with implied consequences for the dynamics of the polar vortex.

Miranda, P. M. A.; Martins, J. P. A.; Teixeira, M. A. C.

2009-09-01

37

Nonlinear surface wave impact on the bottom

NASA Astrophysics Data System (ADS)

The problem to compute the bottom pressure under the nonlinear water waves is studying. Jut now in oceanographic practice, the linear theory of water waves is the most popular in determining the relation between bottom pressure and sea surface. However the linear theory is not entirely correct to analyze strongly wave nonlinear processes. Such processes are for example, storm surge, and abnormally large wave or freak waves. Here numerical solutions of the fully nonlinear equations of motion of an ideal fluid in conformal variables is presented. The comparative evaluation of deficiencies in the linear theory calculating fluid pressure induced by surface waves is analysed. The exact formula for the calculation of the pressure in fluid using a conformal representation of the Euler equation is derived. It is shown the linear theory may underestimate the bottom pressure induced by strongly nonlinear surface waves (ka = 0.08, where k - wave number, a - wave amplitude), more than 17% in a shallow basin (kh = 0.58, where h - depth).

Kuznetsov, Konstantin; Shamin, Roman; Pelinovsky, Efim

2014-05-01

38

Propagation of detonation waves from an impact region

An experimental system was developed to study the propagation of a detonation wave away from a region that is initiated by the impact of a thin flyer plate. The propagation of detonation waves away from this region in pressed pellets of TATB and in RX-26-AF, a TATB\\/HMX formulation is studied. The system permits measurements at elevated, ambient, and low temperatures.

R. S. Lee; W. C. Tao; L. D. Crouch

1989-01-01

39

Wave energy converters and their impact on power systems

The objective of this paper is to give an introduction into ocean wave energy converters and their impact on power systems. The potential of wave energy is very large. There are a lot of different methods and systems for converting this power into electrical power, such as oscillating water columns, hinged contour devices as the Pelamis, overtopping devices as the

Henk Polinder; Mattia Scuotto

2005-01-01

40

Extreme waves impact on the ship mooring near berth

NASA Astrophysics Data System (ADS)

Ensuring safe ships berthing and loading-unloading operations at berths need reliable mooring systems. The choice of its parameters corresponds to calculating of the maximum displacements of the boat, which are caused by external impact of extreme waves, winds, and currents. Ship motions are described by system of differential equations, which contain disturbing, inertia, damping, and restoring forces, which magnitude strongly depends on the berth design and configuration of its elements. The major impact on the boat movements is caused by sea waves. In the given paper, an interaction between sea waves and ship located near the berth is studied. The cross-sectional shape of the boat is assumed to be rectangular and under-berth slope profile is approximated by finite number of steps. Different types of berth constructions are taken into account: containing impermeable or partially permeable front vertical wall, wave attenuation camera behind it with or without under-berth slope. The fluid is assumed ideal and incompressible, and its motion is potential. The stated problem is reduced to the determination of the velocity potential that satisfies the Laplace equation; the boundary condition on the free surface; the condition of non-flux through the impermeable bottom, the ship and berth elements; the condition on the surface of the permeable wall that is in proportionality between the wave flow velocity through the wall and pressure drop from its front to back faces. The problem is solved by dividing of the region into sub-domains with conditions of the hydrodynamic pressure and velocity continuity on its boundaries. In each sub-domain the solution is found using Fourier method in the form of functional series with unknown coefficients which are found from the system of linear algebraic equations. Calculated velocity potentials are used to determine different hydrodynamic characteristics of ship motions, such as horizontal and vertical components of disturbing force and moment, added masses and damping coefficients for all types of boat motions. The results of calculations are presented and they are compared with experimental data performed by authors.

Leont'ev, Victor; Nudner, Igor; Semenov, Konstantin; Pelinovsky, Efim

2013-04-01

41

Applications of elliptic functions to ion-acoustic plasma waves

NASA Astrophysics Data System (ADS)

New several classes of exact solutions are obtained in terms of the Weierstrass elliptic function for some nonlinear partial differential equations modeling ion-acoustic waves as well as dusty plasmas in laboratory and space sciences. The Weierstrass elliptic function solutions of the Schamel equation, a fifth order dispersive wave equation and the Kawahara equation are constructed. Moreover, Jacobi elliptic function solutions and solitary wave solutions of the Schamel equation are also given. The stability of some periodic wave solutions is computationally studied.

Khater, A. H.; Hassan, M. M.; Krishnan, E. V.; Peng, Y. Z.

2008-12-01

42

The Projector Augmented Wave Method: ab-initio molecular dynamics with full wave functions

A brief introduction to the projector augmented wave method is given and recent developments are reviewed. The projector augmented wave method is an all-electron method for efficient ab-initio molecular dynamics simulations with the full wave functions. It extends and combines the traditions of existing augmented wave methods and the pseudopotential approach. Without sacrificing efficiency, the PAW method avoids transferability problems

Peter E. Blöchl; Clemens J. Först; Johannes Schimpl

2002-01-01

43

Guided ultrasonic waves for impact damage detection in composite panels

NASA Astrophysics Data System (ADS)

Carbon fiber laminate composites, consisting of layers of polymer matrix reinforced with high strength carbon fibers, are increasingly employed for aerospace structures. They offer advantages for aerospace applications, e.g., good strength to weight ratio. However, impact during the operation and servicing of the aircraft can lead to barely visible and difficult to detect damage. Depending on the severity of the impact, fiber and matrix breakage or delaminations can occur, reducing the load carrying capacity of the structure. Efficient structural health monitoring of composite panels can be achieved using guided ultrasonic waves propagating along the structure. Impact damage was induced in the composite panels using standard drop weight procedures. The guided wave scattering at the impact damage was measured using a noncontact laser interferometer, quantified, and compared to baseline measurements on undamaged composite panels. Significant scattering of the first anti-symmetrical (A0) guided wave mode was observed, allowing for the detection of barely visible impact damage. The guided wave scattering was modeled using full three-dimensional Finite Element (FE) simulations, and the influence of the different damage mechanisms investigated. Good agreement between experiments and predictions was found. The sensitivity of guided waves for the detection of barely visible impact damage in composite panels has been verified.

Murat, B. I. S.; Khalili, P.; Fromme, P.

2014-03-01

44

NASA Astrophysics Data System (ADS)

As concerns over the use of fossil fuels increase, more and more effort is being put into the search for renewable and reliable sources of energy. Developments in ocean technologies have made the extraction of wave energy a promising alternative. Commercial exploitation of wave energy would require the deployment of arrays of Wave Energy Converters (WECs) that include several to hundreds of individual devices. Interactions between WECs and ocean waves result in both near-field and far-field changes in the incident wave field, including a significant decrease in wave height and a redirection of waves in the lee of the array, referred to as the wave shadow. Nearshore wave height and direction are directly related to the wave radiation stresses that drive longshore currents, rip currents and nearshore sediment transport, which suggests that significant far-field changes in the wave field due to WEC arrays could have an impact on littoral processes. The goal of this study is to investigate the changes in nearshore wave conditions and radiation stress forcing as a result of an offshore array of point-absorber type WECs using a nested SWAN model, and to determine how array size, configuration, spacing and distance from shore influence these changes. The two sites of interest are the Northwest National Marine Renewable Energy Center (NNMREC) test sites off the coast of Newport Oregon, the North Energy Test Site (NETS) and the South Energy Test Site (SETS). NETS and SETS are permitted wave energy test sites located approximately 4 km and 10 km offshore, respectively. Twenty array configurations are simulated, including 5, 10, 25, 50 and 100 devices in two and three staggered rows in both closely spaced (three times the WEC diameter) and widely spaced (ten times the WEC diameter) arrays. Daily offshore wave spectra are obtained from a regional WAVEWATCH III hindcast for 2011, which are then propagated across the continental shelf using SWAN. Arrays are represented in SWAN through the external modification of the wave spectra at the device locations, based on a new experimentally determined Power Transfer Function established in an earlier WEC-array laboratory study. Changes in nearshore forcing conditions for each array size and configuration are compared in order to determine the scale of the far-field effects of WEC arrays and which array sizes and configurations could have the most significant impacts on coastal processes.

O'Dea, A.; Haller, M. C.

2013-12-01

45

Adiabatic corrections to density functional theory energies and wave functions.

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

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

2008-09-25

46

Wave propagation in a plate after impact by a projectile

NASA Technical Reports Server (NTRS)

The wave propagation in a circular plate after impact by a cylindrical projectile is studied. In the vicinity of impact, the pressure is computed numerically. An intense pressure pulse is generated that peaks 0.2 microns after impact, then drops sharply to a plateau. The response of the plate is determined adopting a modal solution of Mindlin's equations. Velocity and acceleration histories display both propagating and dispersive features.

El-Raheb, M.; Wagner, P.

1987-01-01

47

Impact of Functionally Graded Cylinders: Theory

NASA Technical Reports Server (NTRS)

This final report summarizes the work funded under the Grant NAG3-2411 during the 04/05/2000-04/04/2001 period. The objective of this one-year project was to generalize the theoretical framework of the two-dimensional higher-order theory for the analysis of cylindrical functionally graded materials/structural components employed in advanced aircraft engines developed under past NASA Glenn funding. The completed generalization significantly broadens the theory's range of applicability through the incorporation of dynamic impact loading capability into its framework. Thus, it makes possible the assessment of the effect of damage due to fuel impurities, or the presence of submicron-level debris, on the life of functionally graded structural components. Applications involving advanced turbine blades and structural components for the reusable-launch vehicle (RLV) currently under development will benefit from the completed work. The theory's predictive capability is demonstrated through a numerical simulation of a one-dimensional wave propagation set up by an impulse load in a layered half-plane. Full benefit of the completed generalization of the higher-order theory described in this report will be realized upon the development of a related computer code.

Aboudi, Jacob; Pindera, Marek-Jerzy; Arnold, S. M. (Technical Monitor)

2001-01-01

48

An exponential multireference wave-function Ansatz

NASA Astrophysics Data System (ADS)

An exponential multireference wave-function Ansatz is formulated. In accordance with the state universal coupled-cluster Ansatz of Jeziorski and Monkhorst [Phys. Rev. A 24, 1668 (1981)] the approach uses a reference specific cluster operator. In order to achieve state selectiveness the excitation- and reference-related amplitude indexing of the state universal Ansatz is replaced by an indexing which is based on excited determinants. There is no reference determinant playing a particular role. The approach is size consistent, coincides with traditional single-reference coupled cluster if applied to a single-reference, and converges to full configuration interaction with an increasing cluster operator excitation level. Initial applications on BeH2, CH2, Li2, and nH2 are reported.

Hanrath, Michael

2005-08-01

49

Exact microscopic wave function for a topological quantum membrane.

The higher dimensional quantum Hall liquid constructed recently supports stable topological membrane excitations. Here we introduce a microscopic interacting Hamiltonian and present its exact ground state wave function. We show that this microscopic ground state wave function describes a topological quantum membrane. We also construct variational wave functions for excited states using the noncommutative algebra on the four sphere. Our approach introduces a nonperturbative method to quantize topological membranes. PMID:12785968

Zhang, Shou-Cheng

2003-05-16

50

Asymptotic behavior of atomic and molecular wave functions

The asymptotic form of bound-state wave functions is derived by analytic continuation of asymptotic scattering-state wave functions. The result is also regorously derived by using an approach that is independent of scattering theory. One aspect of the result is that the N electron wave function becomes the lowest accessible exact wave function for the remaining N — 1 electrons when one electron is far away from all the nuclei. This shows that the recently developed extended Koopmans' procedures are in principle exact for the first ionization energy.

Katriel, J.; Davidson, E. R.

1980-01-01

51

Holographic Wave Functions, Meromorphization and Counting Rules

We study the large-Q{sup 2} behavior of the meson form factor F{sub M} (Q{sup 2}) constructed using the holographic light-front wave functions proposed recently by Brodsky and de Teramond. We show that this model can be also obtained within the Migdal's regularization approach (''meromorphization''), if one applies it to 3-point function for scalar currents made of scalar quarks. We found that the asymptotic 1/Q{sup 2} behavior of F{sub M} (Q{sup 2}) is generated by soft Feynman mechanism rather than by short distance dynamics, which causes very late onset of the 1/Q{sup 2} asymptotic behavior. It becomes visible only for unaccessible momenta Q{sup 2} {approx}> 10, GeV{sup 2}. Using meromorphization for spin-1/2 quarks, we demonstrated that resulting form factor F{sup spinor}{sub M} (Q{sup 2}) has 1/Q{sup 4} asymptotic behavior. Now, owing to the late onset of this asymptotic pattern, F{sup spinor}{sub M} (Q{sup 2}) imitates the 1/Q{sup 2} behavior in the few GeV{sup 2} region.

Anatoly Radyushkin

2006-05-10

52

Shock Waves Impacting Composite Material Plates: The Mutual Interaction

NASA Astrophysics Data System (ADS)

High-performance, fiber-reinforced polymer composites have been extensively used in structural applications in the last 30 years because of their light weight combined with high specific stiffness and strength at a rather low cost. The automotive industry has adopted these materials in new designs of lightweight vehicles. The mechanical response and characterization of such materials under transient dynamic loading caused with shock impact induced by blast is not well understood. Air blast is associated with a fast traveling shock front with high pressure across followed by a decrease in pressure behind due to expansion waves. The time scales associated with the shock front are typically 103 faster than those involved in the expansion waves. Impingement of blast waves on structures can cause a reflection of the wave off the surface of the structure followed by a substantial transient aerodynamic load, which can cause significant deformation and damage of the structure. These can alter the overpressure, which is built behind the reflected shock. In addition, a complex aeroelastic interaction between the blast wave and the structure develops that can induce reverberation within an enclosure, which can cause substantial overpressure through multiple reflections of the wave. Numerical simulations of such interactions are quite challenging. They usually require coupled solvers for the flow and the structure. The present contribution provides a physics-based analysis of the phenomena involved, a critical review of existing computational techniques together with some recent results involving face-on impact of shock waves on thin composite plates.

Andreopoulos, Yiannis

2013-02-01

53

Antipodal focusing of seismic waves after larger meteorite impacts

NASA Astrophysics Data System (ADS)

We examine focusing of seismic waves at the antipode of large terrestrial meteorite impacts, using the Chicxulub impact as our case study. Numerical simulations are based on a spectral-element method, representing the impact as a Gaussian force in time and space. Simulating the impact as a point source at the surface of a spherically symmetric Earth model results in deceptively large peak displacements at the antipode. Earth's ellipticity, lateral heterogeneity and a spatially distributed source limit high-frequency waves from constructively interfering at the antipode, thereby reducing peak displacement by a factor of four. Nevertheless, for plausible impact parameters, we observe peak antipodal displacements of ˜ 4~m, dynamic stresses in excess of 15~bar, and strains of 2 ± 10-5 . While these values are significantly lower than prior estimates, mainly based on a point source in a spherically symmetric Earth model, wave interference en route to the antipode induces ``channels'' of peak stress that are 5~times greater than in surrounding areas. Underneath the antipode we observed ``chimneys'' of peak stress, strain and velocity, with peak values exceeding 50~bar, 10-5 and 0.1~m/s, respectively. Our results put quantitative constraints on the feasibility of impact-induced antipodal volcanism and seismicity, as well as mantle plume and hotspot formation.

Meschede, M.

2011-12-01

54

Projector augmented wave method: ab initio molecular dynamics with full wave functions

A brief introduction to the projector augmented wave method is given and recent developments are reviewed. The projector augmented\\u000a wave method is an all-electron method for efficient ab initio molecular dynamics simulations with full wave functions. It\\u000a extends and combines the traditions of existing augmented wave methods and the pseudopotential approach. Without sacrificing\\u000a efficiency, the PAW method avoids transferability problems

Peter E. Blöchl; Clemens J. Först; Johannes Schimpl

2003-01-01

55

The Projector Augmented Wave Method: ab-initio molecular dynamics with full wave functions

A brief introduction to the projector augmented wave method is given and\\u000arecent developments are reviewed. The projector augmented wave method is an\\u000aall-electron method for efficient ab-initio molecular dynamics simulations with\\u000athe full wave functions. It extends and combines the traditions of existing\\u000aaugmented wave methods and the pseudopotential approach. Without sacrificing\\u000aefficiency, the PAW method avoids transferability problems

Peter E. Blöchl; Clemens J. Först; Johannes Schimpl

2002-01-01

56

Transient wave propagation in composite plates due to impact

NASA Technical Reports Server (NTRS)

Stress-wave propagation in a composite plate due to an impact has been examined using anisotropic elasticity theory. The plate is modelled as a number of identical anisotropic layers whose elastic moduli are given. Mindlin's (1959) approximate theory of plates is then applied to each layer to obtain a set of difference-differential equations of motion by using the interlaminar stresses and displacements as explicit variables. Dispersion relationships for harmonic waves are found when traction-free boundary conditions are applied to both surfaces of the plate. The difference-differential equations are reduced to difference equations via integral transforms. With given impact boundary conditions these equations are solved for an arbitrary number of layers in the plate, and the transient propagation of a stress wave is calculated by means of a fast Fourier transform algorithm.

Sung Kim, B.; Moon, F.

1977-01-01

57

Breaking wave impact forces on truss support structures for offshore wind turbines

NASA Astrophysics Data System (ADS)

Due to depletion of the conventional energy sources, wind energy is becoming more popular these days. Wind energy is being produced mostly from onshore farms, but there is a clear tendency to transfer wind farms to the sea. The foundations of offshore wind turbines may be truss structures and might be located in shallow water, where are subjected to highly varying hydrodynamic loads, particularly from plunging breaking waves. There are models for impact forces prediction on monopiles. Typically the total wave force on slender pile from breaking waves is a superposition of slowly varying quasi-static force, calculated from the Morison equation and additional dynamical, short duration force due to the impact of the breaker front or breaker tongue. There is not much research done on the truss structures of wind turbines and there are still uncertainties on slamming wave forces, due to plunging breaking waves on those structures. Within the WaveSlam (Wave slamming forces on truss structures in shallow water) project the large scale tests were carried out in 2013 at the Large Wave Flume in Forschungszentrum Küste (FZK) in Hannover, Germany. The following institutions participated in this initiative: the University of Stavanger and the Norwegian University of Science and Technology (project management), University of Gda?sk, Poland, Hamburg University of Technology and the University of Rostock, Germany and Reinertsen AS, Norway. This work was supported by the EU 7th Framework Programme through the grant to the budget of the Integrating Activity HYDRALAB IV. The main aim of the experiment was to investigate the wave slamming forces on truss structures, development of new and improvement of existing methods to calculate forces from the plunging breakers. The majority of the measurements were carried out for regular waves with specified frequencies and wave heights as well as for the irregular waves based on JONSWAP spectrum. The truss structure was equipped with both total and local force transducers which measured the response of the structure to the impact force. Also, the free surface elevations, the water particle velocity and the water particle acceleration were recorded during the WaveSlam experiment. Both the total and the local force data have been analysed using the Frequency Response Function method, which has been already applied to the estimation of the wave slamming forces. The results of this classical approach were compared to the calculated slamming forces based on Goda and Wienke and Oumeraci theories. Slamming wave forces and slamming coefficients calculated using both models appeared to be very much larger than those obtained from the analysed recorded data, therefore there is a need for further research. Details of this research and modelling results will be presented in the final poster.

Cie?likiewicz, Witold; Gudmestad, Ove T.; Podra?ka, Olga

2014-05-01

58

Electronic Wave Functions Round a Vacancy in a Metal

A calculation of the wave functions round a vacancy in a metal has been carried out for a simple model. This corresponds to the case of a finite number of particles in a free-electron metal, with the boundary condition that the wave functions vanish on the surface of the spherical metal. Calculations are reported for particle numbers of approximately 2

N. H. March; A. M. Murray

1960-01-01

59

Interaction of an elastic cylindrical inclusion and a crack in half space impacted by SH-wave

Scattering of SH wave by an elastic half space containing an elastic cylindrical inclusion and a crack of any position and direction is studied by means of Green's function, complex function and multi-polar coordinate system. A suitable Green's function is constructed, which is the fundamental solution of the displacement field for a half space with an elastic cylindrical inclusion impacted

Zai-lin Yang; Pei-lei Yan; Bai-tao Sun

2009-01-01

60

Calculation of electronic excitations using wave-function in wave-function frozen-density embedding

NASA Astrophysics Data System (ADS)

Recently, a general framework suitable for general frozen-density embedding (FDE) methods was published [S. Höfener, A. S. P. Gomes, and L. Visscher, J. Chem. Phys. 136, 044104 (2012)]. In the present article, we report the fragmentation of a supermolecule while treating all subsystems with coupled-cluster theory and the interaction of the subsystems with density-functional theory. This variant is denoted wave-function theory in wave-function theory FDE, or coupled-cluster theory in coupled-cluster theory FDE. Main target of this approach is not the embedding of a single molecule in large solvation shells, but rather the possibility to divide a complex system consisting of several molecules when all subsystems are to be treated with, e.g., coupled-cluster methods to provide a balanced and unbiased description. We present numerical results for hydrogen-bonded complexes which exhibit rather strong interactions. Cases with weakly interacting subsystems are expected to exhibit even higher accuracy. This facilitates the study of properties of larger complexes such as DNA base pairs with coupled-cluster methods.

Höfener, Sebastian; Visscher, Lucas

2012-11-01

61

Propagation of detonation waves from an impact region

NASA Astrophysics Data System (ADS)

An experimental system was developed to study the propagation of a detonation wave away from a region that is initiated by the impact of a thin flyer plate. The propagation of detonation waves away from this region in pressed pellets of TATB and in RX-26-AF, a TATB/HMX formulation is studied. The system permits measurements at elevated, ambient, and low temperatures. The the distance-time trajectory and arrival time of the detonation front at the downstream face of the explosive pellets is measured for pellets with thicknesses of 1 to 16 mm over the temperature range -80 to +80 C.

Lee, R. S.; Tao, W. C.; Crouch, L. D.

62

Green's functions for gravitational waves in FRW spacetimes

A method for calculating the retarded Green's function for the gravitational wave equation in Friedmann-Robertson-Walker spacetimes within the formalism of linearized Einstein gravity is developed. Hadamard's general solution to Cauchy's problem for second-order, linear partial differential equations is applied to the FRW gravitational wave equation. The retarded Green's function may be calculated for any FRW spacetime, with curved or flat spatial sections, for which the functional form of the Ricci scalar curvature [ital R] is known. The retarded Green's function for gravitational waves propagating through a cosmological fluid composed of both radiation and dust is calculated analytically for the first time. It is also shown that for all FRW spacetimes in which the Ricci scalar curvature does not vanish, [ital R][ne]0, the Green's function violates Huygens' principle; the Green's function has support inside the light cone due to the scattering of gravitational waves off the background curvature.

Caldwell, R.R. (NASA/Fermilab Astrophysics Center, Fermi National Accelerator Laboratory, P.O. Box 500, Batavia, Illinois 60510-0500 (United States))

1993-11-15

63

Symmetry-projected wave functions in quantum Monte Carlo calculations

NASA Astrophysics Data System (ADS)

We consider symmetry-projected Hartree-Fock trial wave functions in constrained-path Monte Carlo (CPMC) calculations. Previous CPMC calculations have mostly employed Hartree-Fock (HF) trial wave functions, restricted or unrestricted. The symmetry-projected HF approach results in a hierarchy of wave functions with increasing quality: the more symmetries that are broken and restored in a self-consistent manner, the higher the quality of the trial wave function. This hierarchy is approximately maintained in CPMC calculations: the accuracy in the energy increases and the statistical variance decreases when further symmetries are broken and restored. Significant improvement is achieved in CPMC with the best symmetry-projected trial wave functions over those from simple HF. We analyze and quantify the behavior using the two-dimensional repulsive Hubbard model as an example. In the sign-problem-free region, where CPMC can be made exact but a constraint is deliberately imposed here, spin-projected wave functions remove the constraint bias. Away from half filling, spatial symmetry restoration in addition to that of the spin leads to highly accurate results from CPMC. Since the computational cost of symmetry-projected HF trial wave functions in CPMC can be made to scale algebraically with system size, this provides a potentially general approach for accurate calculations in many-fermion systems.

Shi, Hao; Jiménez-Hoyos, Carlos A.; Rodríguez-Guzmán, R.; Scuseria, Gustavo E.; Zhang, Shiwei

2014-03-01

64

Common generating function for two-dimensional hydrogen atom complete wave functions

The Schrödinger equation for the two-dimensional hydrogen atom is known to be separable and integrable in circular, parabolic, and elliptical coordinates. This makes it possible to construct a common generating function for the complete wave functions of the atom in the respective coordinates. The connections with the corresponding generating function and wave functions for the harmonic oscillator are recognized and

L. Chaos-Cador; E. Ley-Koo

2007-01-01

65

Probing [alpha]-particle wave functions using ([ital [rvec d

Wave functions of the [alpha] particle corresponding to different [ital S]- and [ital D]-state deuteron-deuteron overlaps, [l angle][ital dd][vert bar][alpha][r angle], were investigated using exact finite-range distorted-wave Born-approximation (DWBA) analyses of ([ital [rvec d

Crosson, E.R.; Lemieux, S.K.; Ludwig, E.J.; Thompson, W.J. (University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3255 (United States) Triangle Universities Nuclear Laboratory, Durham, North Carolina 27706 (United States)); Bisenberger, M.; Hertenberger, R.; Hofer, D.; Kader, H.; Schiemenz, P.; Graw, G. (Sektion Physik, Universitaet Muenchen, 8046 Garching (Germany)); Eiro, A.M.; Santos, F.D. (Departamento de Fisica, Universidade de Lisboa, 1700 Lisboa (Portugal))

1993-06-01

66

Properties of wave functions in homogeneous anisotropic media

NASA Astrophysics Data System (ADS)

The general solutions of the first, second, third, and fourth kinds to the wave equation in homogeneous anisotropic media are expressed by integrals over a finite range. The convergence of the series solution of wave functions in homogeneous anisotropic media [Phys. Rev. E 47, 664 (1993)] is discussed. The use of the wave functions in anisotropic media is demonstrated. The theory is expounded via an illustrative example of a two-dimensional scalar case. The analytical solution of plane-wave scattering by a conducting circular cylinder coated with anisotropic materials is formulated in terms of the series of wave functions for anisotropic media. Numerical results show that the solution in terms of wave functions of various kinds in anisotropic media gives essentially the same radar cross sections as obtained by Beker, Umashankar, and Taflove [Electromagnetics 10, 387 (1990)] using a different approach. Numerical results in the resonance region are presented for reference purposes. The analysis of this paper can be easily generalized to vector and tensor wave functions in homogeneous anisotropic media.

Ren, Wei; Wu, Xin Bao; Yi, Zhang; Lin, Wei Gan

1995-01-01

67

Impact of internal waves on the coherent underwater acoustic communication

NASA Astrophysics Data System (ADS)

The 2001 Asian Sea International Experiment (ASIAEX2001) is a large-scale survey performed in the South China Sea. During May 2001 several minutes of M-sequence phase modulation signals were transmitted by a 400-Hz source repeatedly at intervals of half an hour, and received by an array 31 km away to conduct tomography of internal waves. The signal was treated as a binary-phase shift-keying (BPSK) communication signal with an information rate of 100 bps. The communication signals were demodulated by a decision-feedback equalizer. Since the intensity of the internal waves was not stable during the experiment period, data of two transmissions corresponding to a strong and a weak internal-wave activity were separately located and processed to investigate the impact of internal waves on the coherent underwater acoustic communication. The results show that internal waves cause a greatly fluctuating signal level and a rapidly varying multipath structure; consequently, these results show that the parameters of the equalizer need to be adjusted to mitigate the degradation of the communication performance.

Wang, Jun; Yang, Xiaoxia; Wu, Lixin; Wang, Haibin; Lynch, James F.; Newhall, Arthur

2012-11-01

68

Conversion Technique of Vector Wave Functions: Formulas and Applications.

National Technical Information Service (NTIS)

The conversion theory of vector wave function is one of important problems in electromagnetics. This paper presents a systematic treatment of the conversion technique and some applications. In this paper, the conversion relations of standard and non-stand...

P. G. Xu S. Lu

1995-01-01

69

Rotating Waves in Neutral Partial Functional Differential Equations

General results on the existence and global continuation of rotating waves are established for partial neutral functional differential equations defined on the unit circle. These results are applied to a class of coupled lossless transmission lines.

J. Wu; H. Xia

1999-01-01

70

Uniform WKB approximation of Coulomb wave functions for arbitrary partial wave

NASA Astrophysics Data System (ADS)

Coulomb wave functions are difficult to compute numerically for extremely low energies, even with direct numerical integration. Hence, it is more convenient to use asymptotic formulas in this region. It is the object of this paper to derive analytical asymptotic formulas valid for arbitrary energies and partial waves. Moreover, it is possible to extend these formulas for complex values of the parameters.

Michel, N.

2008-07-01

71

Multi-time wave functions for quantum field theory

NASA Astrophysics Data System (ADS)

Multi-time wave functions such as ?(t1,x,…,tN,x) have one time variable tj for each particle. This type of wave function arises as a relativistic generalization of the wave function ?(t,x,…,x) of non-relativistic quantum mechanics. We show here how a quantum field theory can be formulated in terms of multi-time wave functions. We mainly consider a particular quantum field theory that features particle creation and annihilation. Starting from the particle-position representation of state vectors in Fock space, we introduce multi-time wave functions with a variable number of time variables, set up multi-time evolution equations, and show that they are consistent. Moreover, we discuss the relation of the multi-time wave function to two other representations, the Tomonaga-Schwinger representation and the Heisenberg picture in terms of operator-valued fields on space-time. In a certain sense and under natural assumptions, we find that all three representations are equivalent; yet, we point out that the multi-time formulation has several technical and conceptual advantages.

Petrat, Sören; Tumulka, Roderich

2014-06-01

72

Impact of sea-level rise and coral mortality on the wave dynamics and wave forces on barrier reefs.

A one-dimensional wave model was used to investigate the reef top wave dynamics across a large suite of idealized reef-lagoon profiles, representing barrier coral reef systems under different sea-level rise (SLR) scenarios. The modeling shows that the impacts of SLR vary spatially and are strongly influenced by the bathymetry of the reef and coral type. A complex response occurs for the wave orbital velocity and forces on corals, such that the changes in the wave dynamics vary reef by reef. Different wave loading regimes on massive and branching corals also leads to contrasting impacts from SLR. For many reef bathymetries, wave orbital velocities increase with SLR and cyclonic wave forces are reduced for certain coral species. These changes may be beneficial to coral health and colony resilience and imply that predicting SLR impacts on coral reefs requires careful consideration of the reef bathymetry and the mix of coral species. PMID:24768171

Baldock, T E; Golshani, A; Callaghan, D P; Saunders, M I; Mumby, P J

2014-06-15

73

NASA Astrophysics Data System (ADS)

We propose an improved version of the antisymmetrized quasicluster model (AQCM) to describe a smooth transition from the ?-cluster wave function to the jj-coupling shell model wave function and apply it to the ground state of 12C. The cluster-shell transition in 12C is characterized in AQCM by only two parameters: R representing the distance between ? clusters and the center of mass and ? describing the break of ? clusters. The optimal AQCM wave function for the ground state of 12C is an intermediate state between the three-? cluster state and the shell model state with the p3/2 subshell closure configuration. The result is consistent with that of the antisymmetrized molecular dynamics (AMD), and the optimal AQCM wave function quantitatively agrees with the AMD one, although the number of degrees of freedom in AQCM is significantly fewer.

Suhara, Tadahiro; Itagaki, Naoyuki; Cseh, József; P?oszajczak, Marek

2013-05-01

74

Impact of rheumatoid arthritis on sexual function

Sexuality is a complex aspect of the human being’s life and is more than just the sexual act. Normal sexual functioning consists of sexual activity with transition through the phases from arousal to relaxation with no problems, and with a feeling of pleasure, fulfillment and satisfaction. Rheumatic diseases may affect all aspects of life including sexual functioning. The reasons for disturbing sexual functioning are multifactorial and comprise disease-related factors as well as therapy. Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disease characterized by progressive joint destruction resulting from chronic synovial inflammation. It leads to various degrees of disability, and ultimately has a profound impact on the social, economic, psychological, and sexual aspects of the patient’s life. This is a systemic review about the impact of RA on sexual functioning.

Tristano, Antonio G

2014-01-01

75

Parametric dependence of ocean wave-radar modulation transfer functions

NASA Technical Reports Server (NTRS)

Microwave techniques at X and L band were used to determine the dependence of ocean-wave radar modulation transfer functions (MTFs) on various environmental and radar parameters during the Marine Remote Sensing experiment of 1979 (MARSEN 79). These MIF are presented, as are coherence functions between the AM and FM parts of the backscattered microwave signal. It is shown that they both depend on several of these parameters. Besides confirming many of the properties of transfer functions reported by previous authors, indications are found that MTFs decrease with increasing angle between wave propagation and antenna-look directions but are essentially independent of small changes in air-sea temperature difference. However, coherence functions are much smaller when the antennas are pointed perpendicular to long waves. It is found that X band transfer functions measured with horizontally polarized microwave radiation have larger magnitudes than those obtained by using vertical polarization.

Plant, W. J.; Keller, W. C.; Cross, A.

1983-01-01

76

Improved WKB radial wave functions in several bases

We develop approximate WKB-like solutions to the radial Schroedinger equation for problems with an angular momentum barrier using Riccati-Bessel, Coulomb, and harmonic-oscillator functions as basis functions. The solutions treat the angular momentum singularity near the origin more accurately in leading approximation than the standard WKB solutions based on sine waves. The solutions based on Riccati-Bessel and free Coulomb wave functions continue smoothly through the inner turning point and are appropriate for scattering problems. The solutions based on oscillator and bound Coulomb wave functions incorporate both turning points smoothly and are particularly appropriate for bound-state problems; no matching of piecewise solutions using Airy functions is necessary.

Durand, B.; Durand, L.

1986-05-01

77

Propagation of detonation waves from an impact region

We have developed an experimental system for studying the propagation of a detonation wave away from a region that is initiated by the impact of a thin flyer plate. We have studied the propagation of detonation waves away from this region in pressed pellets of TATB and in RX-26-AF, a TATB/HMX formulation. The system permits measurements at elevated, ambient and low temperatures. We measured the distance-time trajectory and arrival time of the detonation front at the downstream face of the explosive pellets for pellets with thicknesses of 1-16 mm over the temperature range -80{degree}C to +80{degree}C. 9 refs., 10 figs.

Lee, R.S.; Tao, W.C.; Crouch, L.D.

1989-01-01

78

Impact of an oblique breaking wave on a wall

NASA Astrophysics Data System (ADS)

The intention of this paper is to study impact force of an oblique-angled slamming wave acting on a rigid wall. In the present study the analytical approach is pursued based on a technique proposed by Shu (Proceedings of the International Conference on Applied Mathematics & Mathematical Physics, Sylhet, Bangladesh, 2000). A nonlinear theory in the context of potential flow is presented for determining accurately the free-surface profiles immediately after an oblique breaking wave impingement on the rigid vertical wall that suddenly starts from rest. The small-time expansion is taken as far as necessary to include the accelerating effect. The analytical solutions for the free-surface elevation are derived up to the third order. The results derived in this paper are of particular interest to the marine and offshore engineering industries, which will find the information useful for the design of ships, coastal and offshore.

Shu, Jian-Jun

2004-03-01

79

Pfaffian wave functions and topology of fermion nodes

NASA Astrophysics Data System (ADS)

Pfaffian is defined as a signed sum of all pair partitions of even number of elements and it can be viewed as a nontrivial generalization of determinant. Pfaffian enables to define the simplest possible antisymmetric wave function based on pair spinorbital(s) and therefore represents a pairing generalization of the Slater determinant of one-particle orbitals. Pfaffians actually accomodate several types of pairing wave functions, for example, one special case is the Bardeen-Cooper- Schrieffer wave function. Using this platform we propose pfaffian wave functions with simultaneous pairings both in singlet and triplet channels and we benchmark their performance in fixed-node quantum Monte Carlo. We implement Gaussian elimination-like algorithm which enables to calculate pfaffians with efficiency similar to calculation of determinants. For a testing set of first row atoms and molecules we show that single pfaffians provide correlation energies systematically at the level of about 95%. Linear combinations of small number of pfaffians recover another fraction of the missing correlation energy comparable to significantly larger determinantal expansions. In addition, we show that pfaffians possess an important property of fermionic wave functions, namely, the minimal number of two nodal domains defined by fermion nodes. This is related to the proof that under rather general conditions closed-shell ground state wave functions of fermionic systems in d>1 have two nodal domains for arbitrary system size. The explicit proofs cover a number of paradigmatic models such as fermions on a sphere surface, in a periodic box, atomic states, etc, and we discuss the implications of this on efficient construction of wave functions and on several types of many-body effects. Supported by NSF and done in collaboration with M. Bajdich, L.K. Wagner, G. Drobny, and K.E Schmidt.Refs: L. Mitas, PRL 96, 240402 (2006); L. Mitas, cond-mat/0605550; M. Bajdich et al, PRL 96, 130201 (2006); cond-mat/0610850.

Mitas, Lubos

2007-03-01

80

Impact of boat-generated waves on intertidal estuarine sediments

NASA Astrophysics Data System (ADS)

Hydrodynamics in the macrotidal Seine estuary (France) are controlled by the semi-diurnal tidal regime modulated seasonally by the fluvial discharge. Wind effect on sediment transport (through wind waves and swell) is observed at the mouth of the estuary. Over the last century, authorities have put emphasis on facilitating economic exchanges by means of embankment building and increased dredging activity. These developments led to allow and secure sea vessel traffic in the Seine estuary (from its mouth to the port of Rouen, 125 km upstream) but they also resulted in a change of estuarine hydrodynamics and sediment transport features. A riversides restoration policy has been recently started by port authorities. In this context, the objective of the field-based study presented is to connect vessel characteristics (i.e. speed, draft...), boat-generated waves and their sedimentary impacts. Such information will be used by stakeholders to manage riverside. The natural intertidal site of interest is located in the fluvial freshwater part of the Seine estuary characterized by a 4.5 m maximum tidal range. The foreshore slope is gently decreasing and surface sediments are composed of fine to coarse sand with occasional mud drapes. In order to decipher boat-generated events, the sampling strategy is based on continuous ADV measurements coupled with a turbidimeter and an altimeter to study sediment dynamics. These instruments are settled in the lower part of the foreshore (i) to obtain a significant dataset (i.e. oceanic instruments are not measuring in air) on a zone statically affected by boat waves and (ii) because most of boat traffic occurs during early flood or late ebb period. Spatial variations are assessed along a cross-section through grain-size analysis of surface sediments and topography measurements using pole technique. Results enhance hydrodynamic and sedimentary impacts of boat-generated waves compared respectively to tidal and wind effects. Long-term altimeter measurements in relation with boat traffic data base demonstrate that boat-generated waves are the key hydrodynamic parameter controlling short term tidal flat evolution. Concerning hydrodynamics, two main types of boat-generated waves can be distinguished: one corresponds to barges, the other to sea vessels. The critical parameter controlling wave characteristics, bottom shear stress and thus sedimentary impacts is the distance between seabed and keel. Thus, considering their larger seabed-keel distance, barges do not significantly affect the sedimentary cover of the intertidal area. On the contrary, sea-vessels can induce rapid changes of the tidal flat texture (i.e. bed flattening, mud drapes...) and morphology: erosion and sedimentation rates in a range of 0.5 to 6 cm.min-1 have been measured. Such energetic events occur generally during the squat generated wave run-up and can affect the seabed in water depths up to 1.5 m. In the freshwater part of the Seine estuary annual sediment inputs are mostly controlled by river flow (during river flood) while medium term scale evolution is dependent on tidal range and short term sediment dynamics (i.e. bedload, resuspension) on sea-vessels waves.

Blanpain, O.; Deloffre, J.; Lafite, R.; Gomit, G.; Calluaud, D.; David, L.

2010-12-01

81

NASA Astrophysics Data System (ADS)

Empirical Green's functions (EGFs) between receivers can be obtained from seismic interferometry through cross-correlation of pairs of ground motion records. Full reconstruction of the Green's function requires diffuse wavefields or a uniform distribution of (noise) sources. In practice, EGFs differ from actual Green's functions because wavefields are not diffuse and the source distribution not uniform. This difference, which may depend on medium heterogeneity, complicates (stochastic) medium characterization as well as imaging and tomographic velocity analysis with EGFs. We investigate how source distribution and scale lengths of medium heterogeneity influence surface wave Green's function reconstruction in the period band of primary microseisms ( T = 10-20 s). With data from a broad-band seismograph array in SE Tibet we analyze the symmetry and travel-time properties of surface wave EGFs from correlation of data in different windows: ambient noise, direct surface waves, and surface wave coda. The EGFs from these different windows show similar dispersion characteristics, which demonstrates that the Green's function can be recovered from direct wavefields (e.g., ambient noise or earthquakes) or from wavefields scattered by heterogeneity on a regional scale. Directional bias and signal-to-noise ratio of EGFs can be understood better with (plane wave) beamforming of the energy contributing to EGF construction. Beamforming also demonstrates that seasonal variations in cross-correlation functions correlate with changes in ocean activity.

Yao, Huajian; Campman, Xander; de Hoop, Maarten V.; van der Hilst, Robert D.

2009-11-01

82

Approximate Electronic Energy Surfaces from Cuspless Wave Functions

The eigenfunctions of a molecular Hamiltonian in which all Coulomb potentials have been replaced by Hooke's law potentials are easily determined. Their electronic parts are essentially single-particle single-center harmonic oscillator, or Gaussian wave functions originating at the center of nuclear charge. An investigation is made to determine the feasibility of using these cuspless base functions in variational calculations of relative

Carl E. Wulfman

1960-01-01

83

Delta function excitation of waves in the earth's ionosphere

NASA Technical Reports Server (NTRS)

Excitation of the earth's ionosphere by delta function current sheets is considered, and the temporal and spatial evolution of wave packets is analyzed for a two-component collisional F2 layer. Approximations of an inverse Fourier-Laplace transform via saddle point methods provide plots of typical wave packets. These illustrate cold plasma wave theory and may be used as a diagnostic tool since it is possible to relate specific features, e.g., the frequency of a modulation envelope, to plasma parameters such as the electron cyclotron frequency. It is also possible to deduce the propagation path length and orientation of a remote radio beacon.

Vidmar, R. J.; Crawford, F. W.; Harker, K. J.

1983-01-01

84

Spin and the Thermal Equilibrium Distribution of Wave Functions

NASA Astrophysics Data System (ADS)

Consider a quantum system S weakly interacting with a very large but finite system B called the heat bath, and suppose that the composite S?B is in a pure state ? with participating energies between E and E+? with small ?. Then, it is known that for most ? the reduced density matrix of S is (approximately) equal to the canonical density matrix. That is, the reduced density matrix is universal in the sense that it depends only on S's Hamiltonian and the temperature but not on B's Hamiltonian, on the interaction Hamiltonian, or on the details of ?. It has also been pointed out that S can also be attributed a random wave function ? whose probability distribution is universal in the same sense. This distribution is known as the "Scrooge measure" or "Gaussian adjusted projected (GAP) measure"; we regard it as the thermal equilibrium distribution of wave functions. The relevant concept of the wave function of a subsystem is known as the "conditional wave function." In this paper, we develop analogous considerations for particles with spin. One can either use some kind of conditional wave function or, more naturally, the "conditional density matrix," which is in general different from the reduced density matrix. We ask what the thermal equilibrium distribution of the conditional density matrix is, and find the answer that for most ? the conditional density matrix is (approximately) deterministic, in fact (approximately) equal to the canonical density matrix.

Pandya, Viraj; Tumulka, Roderich

2013-09-01

85

General trial wave functions for a three body interaction

NASA Astrophysics Data System (ADS)

The Pfaffian wave function, which is a candidate for the 5/2 FQHE state, is the exact ground state of a short range three body model interaction, but little is known about the solutions of this model at other filling factors. Our starting point is the observation that the Pfaffian can be obtained by fully anti-symmetrizing a bilayer wave function of Halperin. A more general class of composite fermion wave functions for bilayer systems was constructed by Scarola and Jain. We find that, upon full antisymmetrization, these wave function provide a decent approximation to the low energy solutions of the three body model interaction at filling factors other than 1/2. The charged and neutral excitations of the full state are naturally constructed by creating excitations in one or both ``layers.'' We also investigate how well the ground and excited state wave functions work for the Coulomb interaction, both in the lowest and the second Landau levels. Systems with up to 18 particles are studied by a combination of exact diagonalization and Monte Carlo method.

Ganesh Jaya, Sreejith; Toke, Csaba; Jain, Jainendra

2010-03-01

86

Quantum Corral Wave-function Engineering

NASA Astrophysics Data System (ADS)

We present a theoretical method for the design and optimization of quantum corrals[1] with specific electronic properties. Taking advantage that spins are subject to a RKKY interaction that is directly controlled by the scattering of the quantum corral, we design corral structures that reproduce spin Hamiltonians with coupling constants determined a priori[2]. We solve exactly the bi-dimensional scattering problem for each corral configuration within the s-wave approximation[3] and subsequently the geometry of the quantum corral is optimized by means of simulated annealing[4] and genetic algorithms[5]. We demonstrate the possibility of automatic design of structures with complicated target electronic properties[6]. This work was performed under the auspices of the US Department of Energy by the University of California at the LLNL under contract no W-7405-Eng-48. [1] M. F. Crommie, C. P. Lutz and D. M. Eigler, Nature 403, 512 (2000) [2] D. P. DiVincenzo et al., Nature 408, 339 (2000) [3] G. A. Fiete and E. J. Heller, Rev. Mod. Phys. 75, 933 (2003) [4] M. R. A. T. N. Metropolis et al., J. Chem. Phys. 1087 (1953) [5] E. Aarts and J. K. Lenstra, eds. Local search in combinatorial problems (Princeton University Press, 1997) [6] A. A. Correa, F. Reboredo and C. Balseiro, Phys. Rev. B (in press).

Correa, Alfredo; Reboredo, Fernando; Balseiro, Carlos

2005-03-01

87

Helicon Wave Physics Impacts on Electrodeless Thruster Design

NASA Technical Reports Server (NTRS)

Effective generation of helicon waves for high density plasma sources is determined by the dispersion relation and plasma power balance. Helicon wave plasma sources inherently require an applied magnetic field of .01-0.1 T, an antenna properly designed to couple to the helicon wave in the plasma, and an rf power source in the 10-100 s of MHz, depending on propellant choice. For a plasma thruster, particularly one with a high specific impulse (>2000 s), the physics of the discharge would also have to address the use of electron cyclotron resonance (ECR) heating and magnetic expansion. In all cases the system design includes an optimized magnetic field coil, plasma source chamber, and antenna. A preliminary analysis of such a system, calling on experimental data where applicable and calculations where required, has been initiated at Glenn Research Center. Analysis results showing the mass scaling of various components as well as thruster performance projections and their impact on thruster size are discussed.

Gilland, James

2003-01-01

88

Dirac single-particle wave functions in inelastic electron scattering

We formulate inelastic electron scattering using Dirac single-particle wave functions to describe the nuclear states. The lower components of these wave functions are much larger than those obtained assuming a free space relation with the upper component taken to be a Schroedinger single-particle wave function. We note that the impulse approximation to the nuclear current operator is ambiguous in the present case. However, one of the two possible forms yields an explicitly conserved current in the single particle limit. We identify an inelastic amplitude which is linear in the lower components and is therefore very sensitive to the ''relativity'' of the bound nucleons. This amplitude is found to be dominant for transverse isoscalar transitions.

Shepard, J.R.; Rost, E.; Siciliano, E.R.; McNeil, J.A.

1984-06-01

89

Dirac single-particle wave functions in inelastic electron scattering

NASA Astrophysics Data System (ADS)

We formulate inelastic electron scattering using Dirac single-particle wave functions to describe the nuclear states. The lower components of these wave functions are much larger than those obtained assuming a free space relation with the upper component taken to be a Schrödinger single-particle wave function. We note that the impulse approximation to the nuclear current operator is ambiguous in the present case. However, one of the two possible forms yields an explicitly conserved current in the single particle limit. We identify an inelastic amplitude which is linear in the lower components and is therefore very sensitive to the "relativity" of the bound nucleons. This amplitude is found to be dominant for transverse isoscalar transitions.

Shepard, J. R.; Rost, E.; Siciliano, E. R.; McNeil, J. A.

1984-06-01

90

Hydrogen-oscillator connection: Passage formulas between wave functions

Recent works on the hydrogen-oscillator connection are extended to cover in a systematic (and easily computarizable) way the problem of the expansion of an R/sup 3/ hydrogen wave function in terms of R/sup 4/ oscillator wave functions. Passage formulas from oscillator to hydrogen wave functions are obtained in six cases resulting from the combination of the following coordinate systems: spherical and parabolic coordinate systems for the hydrogen atom in three dimensions, and Cartesian, double polar, and hyperspherical coordinate systems for the isotropic harmonic oscillator in four dimensions. These coordinate systems are particularly useful in physical applications (e.g., Zeeman and Stark effects for hydrogenlike ions and coherent state approaches to the Coulomb problem).

Kibler, M.; Ronveaux, A.; Negadi, T.

1986-06-01

91

Student use of a material anchor for quantum wave functions

NSDL National Science Digital Library

We explain the appropriate use of pipe cleaners to represent quantum wave functions in terms of material anchors. We then analyze the actions of one undergraduate quantum mechanics student in an oral exam situation with two related tasks, both involving the visualization of a 3-d structure to represent the real and imaginary parts of the wave function on one spatial coordinate. Instruction before the exam included several in-class activities involving building 3-d representations of wave functions for several potentials using pipe cleaners. Though the oral exam did not specify that students should or should not use pipe cleaners, the student in this analysis brought and used them successfully during the exam. Analysis of the studentsâ use of this tool shows promise of benefit to future students in a more highly structured environment of instruction and assessment.

Schiber, Catherine C.; Close, Hunter G.; Close, Eleanor W.; Donnelly, David

2014-02-01

92

Diving-wave migration using Airy functions

A method is described for imaging seismic reflection data selected from a data volume, comprising: preprocessing said selected seismic reflection data by application of normal moveout, dip moveout and a time-domain-to-frequency-domain transformation; determining the velocity field characteristic of said data volume; forming a velocity model for said data volume by fitting a velocity function to said velocity field, said function being characterized by a linear gradient in sloth; from the velocity model, calculating parameters for defining an Airy operator; separating normal seismic data from evanescent seismic data and saving said evanescant data in a random access memory; iterating downwardly, migrating said normal seismic data with the aid of said Airy operator; extracting said evanescent data from memory and iterating upwardly, migrating said evanescent seismic data with the aid of said Airy operator; summing the results of the downward and upward iterations; and inversely Fourier-transforming the summation.

Albertin, U.K.

1993-08-10

93

Wave propagation of functionally graded material plates in thermal environments.

The wave propagation of an infinite functionally graded plate in thermal environments is studied using the higher-order shear deformation plate theory. The thermal effects and temperature-dependent material properties are both taken into account. The temperature field considered is assumed to be a uniform distribution over the plate surface and varied in the thickness direction only. Material properties are assumed to be temperature-dependent, and graded in the thickness direction according to a simple power law distribution in terms of the volume fractions of the constituents. Considering the effects of transverse shear deformation and rotary inertia, the governing equations of the wave propagation in the functionally graded plate are derived by using the Hamilton's principle. The analytic dispersion relation of the functionally graded plate is obtained by solving an eigenvalue problem. Numerical examples show that the characteristics of wave propagation in the functionally graded plate are relates to the volume fraction index and thermal environment of the functionally graded plate. The influences of the volume fraction distributions and temperature on wave propagation of functionally graded plate are discussed in detail. The results carried out can be used in the ultrasonic inspection techniques and structural health monitoring. PMID:21663930

Sun, Dan; Luo, Song-Nan

2011-12-01

94

Accretion of Cometary Material as a Function of Impact Angle

NASA Astrophysics Data System (ADS)

It has been proposed that comets provided the raw ingredients for life during the first billion years of our planet's history. To investigate this possibility, we simulated comet-Earth impacts at a variety of impact angles. Our goal was to determine the mass fraction of material that would be likely to survive a terrestrial impact and come to rest as an isolated pond of water. We employed the Eulerian adaptive mesh refinement (AMR) code, GEODYN, in a 2-D, Cartesian (plane-strain) system. In the calculations, the impactors were modeled as solid-ice comets 1 km in diameter impacting into granite at escape velocity (11.2 km/s). The simulations were computed to a time of 2 seconds, long enough for multiple reverberations of the compression and rarefaction waves to propagate through the comet. Thermomechanical variables relevant to assessing comet conditions during the impact event were monitored at 1000 evenly distributed locations throughout the comet. At each location, the magnitude and orientation of the particle velocity vector were used to determine the fraction of comet mass that escapes Earth's gravity during the impact event. Pressure, density and temperature were also monitored to assess the survivability of organic matter distributed thoughout the comet. We determined that the fraction of comet mass that escapes Earth's gravity is not a simple monotonic function of impact angle. For example, the 15° impact showed the least accretion (61%) and the 90° impact had total accretion, but the 10° impact retained significantly more mass (at 71%) than the 15° impact. We also found that a significant amount of the comet experiences low peak temperatures; this was somewhat surprising given that the Earth target was a granitic hard rock. Approximately 80% (or 3x108kg) of the 10° impactor experienced temperatures between 250-350° C and corresponding pressures of 4.5-8.2 GPa. If the organic matter present in comets experienced similar conditions, we would expect it to survive with little deleterious alteration. We will consider the dispersion and final aerial distribution of our comet impactors. We will present our results using the phase diagram for H2O and experimental data from hypervelocity impact experiments. This work was performed under the auspices of the U.S. Department of Energy by University of California Lawrence Livermore National Laboratory under contract No. W-7405-Eng-48.

Karlow, B. A.; Lomov, I.; Antoun, T.; Blank, J. G.

2003-12-01

95

Wave-function recombination instability in cold-atom interferometers

Cold-atom interferometers use guiding potentials that split the wave function of the Bose-Einstein condensate and then recombine it. We present a theoretical analysis of the wave-function recombination instability that is due to the weak nonlinearity of the condensate. It is most pronounced when the accumulated phase difference between the arms of the interferometer is close to an odd multiple of {pi} and consists in exponential amplification of the weak ground state mode by the strong first excited mode. The instability exists for both trapped-atom and beam interferometers.

Stickney, James A.; Zozulya, Alex A. [Department of Physics, WPI, 100 Institute Road, Worcester, Massachusetts 01609 (United States)

2002-11-01

96

Wave-function recombination instability in cold-atom interferometers

NASA Astrophysics Data System (ADS)

Cold-atom interferometers use guiding potentials that split the wave function of the Bose-Einstein condensate and then recombine it. We present a theoretical analysis of the wave-function recombination instability that is due to the weak nonlinearity of the condensate. It is most pronounced when the accumulated phase difference between the arms of the interferometer is close to an odd multiple of ? and consists in exponential amplification of the weak ground state mode by the strong first excited mode. The instability exists for both trapped-atom and beam interferometers.

Stickney, James A.; Zozulya, Alex A.

2002-11-01

97

Many-body wave function in a dipole blockade configuration

We report the results of simulations of the many atom wave function when a cold gas is excited to highly excited states. We simulated the many body wave function by direct numerical solution of Schroedinger's equation. We investigated the fraction of atoms excited and the correlation of excited atoms in the gas for different types of excitation when the blockade region was small compared to the sample size. We also investigated the blockade effect when the blockade region is comparable to the sample size to determine the sensitivity of this system and constraints for quantum information.

Robicheaux, F.; Hernandez, J. V. [Department of Physics, Auburn University, Alabama 36849-5311 (United States)

2005-12-15

98

Exact wave functions in a noncommutative field theory.

We consider the nonrelativistic field theory with a quartic interaction on a noncommutative plane and compute the 2-->2 scattering amplitude within perturbative analysis to all orders. We regain the results of the perturbative analysis by finding the scattering and the bound state wave functions of the two particle Schrodinger equation. These wave functions unusually have two center positions in the relative coordinates, whose separation is transverse to the total momentum and scales linearly with its magnitude, exhibiting the stringy nature of the noncommutative field theory. PMID:11019273

Bak, D; Kim, S K; Soh, K S; Yee, J H

2000-10-01

99

Evolution of wave function in a dissipative system

NASA Technical Reports Server (NTRS)

For a dissipative system with Ohmic friction, we obtain a simple and exact solution for the wave function of the system plus the bath. It is described by the direct product in two independent Hilbert space. One of them is described by an effective Hamiltonian, the other represents the effect of the bath, i.e., the Brownian motion, thus clarifying the structure of the wave function of the system whose energy is dissipated by its interaction with the bath. No path integral technology is needed in this treatment. The derivation of the Weisskopf-Wigner line width theory follows easily.

Yu, Li-Hua; Sun, Chang-Pu

1994-01-01

100

NASA Astrophysics Data System (ADS)

The WAVEWATCH-III model is used operationally as part of the PREVIMER coastal forecast system. A global version of the model provides boundary conditions for a series of stand-alone high-resolution regional sub-domains, on unstructured grids, which are coupled with the regional ocean model MARS. New developments in the WW3 model include a combination of dissipation parameterisations (Ardhuin et al 2010). An anisotropic breaking-induced wind wave dissipation has been based on the local saturation spectrum, with a higher dissipation rate in the mean wave direction, designed to fit observed directional spreading. Additionally, a cumulative dissipation rate inspired by Babanin and Young (2005) but directly estimated from breaking wave probabilities dramatically enhances the dissipation at frequencies greater than 3 times the peak frequency. Regarding swell, a non-linear dissipation based on SAR-derived dissipation rates across the Pacific (Ardhuin et al., 2009) has been introduced. Validation of this model (Rascle and Ardhuin 2012, submitted) using a global hindcast from 1994-2010 shows improvements in significant wave height compared to an altimeter database, with values <10% in general. Regarding extreme events, Hanafin et al (2012) showed that the prediction of the timing of arrival, peak period and spectral distribution of very long swell generated by hurricane-level winds in the North Atlantic compared very well to coastal buoy observations. One of the aims of such improvements is to assist users by providing better geophysical parameters as output. Improvements noted in the mean squared slope compared to buoys, for example, implies a larger amount of energy is available to near-surface Langmuir turbulence. A recent study using the WW3 wave model and the MARS ocean model (Ardhuin et al, in press, JPO 2012) focused on near-shore wave interaction with strong currents. At small scales, rapid steepening of wave slopes by opposing currents induces enhanced breaking as the group velocity decreases. In the study area, tidal currents of up to 4m/s which are highly coherent over the water column and a high wind event created excellent conditions to test the performance of the model. A surface current radar with a resolution of 1km due to multiple signal classification algorithm and a number of buoys were used for validation. Adding currents in the wave model reduced the errors by up to 30% and clearly showed the effects of wave trapping by the strong tidal currents. Comparing different dissipation parameterisations, however, showed that none were completely satisfactory, indicating that further research is required in this area. For short wind waves, the relative wind at the air-sea interface becomes an important factor. At larger scales, waves are refracted by currents. In these cases, the choice of dissipation parameterisation was found to be less important when only one partition was present, though Ardhuin et al (2010) showed better results in mixed seas. Tidal modulations were shown to be due to currents, rather than water level, and a large impact was observed down-wave of currents that have large refraction effects as well as in the vicinity of the currents.

Hanafin, J. A.; Ardhuin, F.; Roland, A.; Leckler, F.; Rascle, N.

2012-12-01

101

Impact! Chandra Images a Young Supernova Blast Wave

NASA Astrophysics Data System (ADS)

Two images made by NASA's Chandra X-ray Observatory, one in October 1999, the other in January 2000, show for the first time the full impact of the actual blast wave from Supernova 1987A (SN1987A). The observations are the first time that X-rays from a shock wave have been imaged at such an early stage of a supernova explosion. Recent observations of SN 1987A with the Hubble Space Telescope revealed gradually brightening hot spots from a ring of matter ejected by the star thousands of years before it exploded. Chandra's X-ray images show the cause for this brightening ring. A shock wave is smashing into portions of the ring at a speed of 10 million miles per hour (4,500 kilometers per second). The gas behind the shock wave has a temperature of about ten million degrees Celsius, and is visible only with an X-ray telescope. "With Hubble we heard the whistle from the oncoming train," said David Burrows of Pennsylvania State University, University Park, the leader of the team of scientists involved in analyzing the Chandra data on SN 1987A. "Now, with Chandra, we can see the train." The X-ray observations appear to confirm the general outlines of a model developed by team member Richard McCray of the University of Colorado, Boulder, and others, which holds that a shock wave has been moving out ahead of the debris expelled by the explosion. As this shock wave collides with material outside the ring, it heats it to millions of degrees. "We are witnessing the birth of a supernova remnant for the first time," McCray said. The Chandra images clearly show the previously unseen, shock-heated matter just inside the optical ring. Comparison with observations made with Chandra in October and January, and with Hubble in February 2000, show that the X-ray emission peaks close to the newly discovered optical hot spots, and indicate that the wave is beginning to hit the ring. In the next few years, the shock wave will light up still more material in the ring, and an inward moving, or reverse, shock wave will heat the material ejected in the explosion itself. "The supernova is digging up its own past," said McCray. The observations were made on October 6, 1999, using the Advanced CCD Imaging Spectrometer (ACIS) and the High Energy Transmission Grating, and again on January 17, 2000, using ACIS. Other members of the team were Eli Michael of the University of Colorado; Dr. Una Hwang, Dr. Steven Holt and Dr. Rob Petre of NASA's Goddard Space Flight Center in Greenbelt, MD; Professor Roger Chevalier of the University of Virginia, Charlottesville; and Professors Gordon Garmire and John Nousek of Pennsylvania State University. The results will be published in an upcoming issue of the Astrophysical Journal. The ACIS instrument was built for NASA by the Massachusetts Institute of Technology, Cambridge, and Pennsylvania State University. The High Energy Transmission Grating was built by the Massachusetts Institute of Technology. NASA's Marshall Space Flight Center in Huntsville, AL, manages the Chandra program. TRW, Inc., Redondo Beach, CA, is the prime contractor for the spacecraft. The Smithsonian's Chandra X-ray Center controls science and flight operations from Cambridge, MA. More About SN 1987A Images to illustrate this release and more information on Chandra's progress can be found on the Internet at: http://chandra.harvard.edu/photo/2000/sn1987a/index.html AND http://chandra.nasa.gov More About SN 1987A

2000-05-01

102

A Green's function method for surface acoustic waves in functionally graded materials.

Acoustic wave propagation in anisotropic media with one-dimensional inhomogeneity is discussed. Using a Green's function approach, the wave equation with inhomogeneous variation of elastic property and mass density is transformed into an integral equation, which is then solved numerically. The method is applied to find the dispersion relation of surface acoustic waves for a medium with continuously or discontinuously varying elastic property and mass density profiles. PMID:17552695

Matsuda, Osamu; Glorieux, Christ

2007-06-01

103

Hydrodynamic waves and correlation functions in dusty plasmas

A hydrodynamic description of strongly coupled dusty plasmas is given when physical quantities vary slowly in space and time and the system can be assumed to be in local thermodynamic equilibrium. The linear waves in such a system are analyzed. In particular, a dispersion equation is derived for low-frequency dust acoustic waves, including collisional damping effects, and compared with experimental results. The linear response of the system is calculated from the fluctuation-dissipation theorem and the hydrodynamic equations. The requirement that these two calculations coincide constrains the particle correlation function for slowly varying perturbations. It is shown that in the presence of weakly damped, long-wavelength dust-acoustic waves, the dust autocorrelation function is of the Debye{endash}H{umlt u}ckel form and the characteristic shielding distance is the dust Debye length. {copyright} {ital 1997 American Institute of Physics.}

Wang, X.; Bhattacharjee, A. [Department of Physics and Astronomy, University of Iowa, Iowa City, Iowa 52242 (United States)] [Department of Physics and Astronomy, University of Iowa, Iowa City, Iowa 52242 (United States)

1997-11-01

104

Surface acoustic wave depth profiling of a functionally graded material

The potential and limitations of Rayleigh wave spectroscopy to characterize the elastic depth profile of heterogeneous functional gradient materials are investigated by comparing simulations of the surface acoustic wave dispersion curves of different profile-spectrum pairs. This inverse problem is shown to be quite ill posed. The method is then applied to extract information on the depth structure of a glass-ceramic (alumina) functionally graded material from experimental data. The surface acoustic wave analysis suggests the presence of a uniform coating region consisting of a mixture of Al{sub 2}O{sub 3} and glass, with a sharp transition between the coating and the substrate. This is confirmed by scanning electron microscope with energy dispersive x-ray analysis.

Goossens, Jozefien; Leclaire, Philippe; Xu Xiaodong; Glorieux, Christ; Martinez, Loic; Sola, Antonella; Siligardi, Cristina; Cannillo, Valeria; Van der Donck, Tom; Celis, Jean-Pierre [Laboratorium voor Akoestiek en Thermische Fysica, Departement Natuurkunde en Sterrenkunde, Katholieke Universiteit Leuven, PO 2416, Celestijnenlaan 200D, B-3001 Leuven (Belgium); Equipe Circuit Instrumentation et Modelisation en Electronique (ECIME) IUP GE, Universite de Cergy, Rue de Eragny, Neuville sur Oise, 95031 Cergy Pontoise Cedex (France); Dipartimento di Ingegneria dei Materiali e dell' Ambiente, University of Modena and Reggio Emilia, Via Vignolese 905, 41100 Modena (Italy); Departement Department of Metallurgy and Materials Engineering (MTM), Katholieke Universiteit Leuven, PO 2450, Kasteelpark Arenberg 44, B-3001 Heverlee (Belgium)

2007-09-01

105

Calculation of the nucleon structure function from the nucleon wave function

NASA Technical Reports Server (NTRS)

Harmonic oscillator wave functions have played an historically important role in our understanding of the structure of the nucleon, most notably by providing insight into the mass spectra of the low-lying states. High energy scattering experiments are known to give us a picture of the nucleon wave function at high-momentum transfer and in a frame in which the nucleon is traveling fast. A simple model that crosses the twin bridges of momentum scale and Lorentz frame that separate the pictures of the nucleon wave function provided by the deep inelastic scattering data and by the oscillator model is presented.

Hussar, Paul E.

1993-01-01

106

SIMULATION OF ROGUE WAVES AND THEIR IMPACT ON MARINE STRUCTURES

The design of safe and economic ofishore structures and ships requires detailed knowledge of the extreme wave environment and the corresponding loads and motions. For the investigation of wave\\/structure interaction and for the analysis of extreme wave events this paper de- scribes techniques to synthesize nonlinear gravity waves in irregular seas. Extreme waves registered in nature are simulated in a

F. Clauss; Christian E. Schmittner; Janou Hennig

2003-01-01

107

Towards model independent single-particle wave functions

We report some results for light nuclei that strongly suggest that it is possible to construct good nuclear single-particle wave functions on the basis of recently available, shell related experimental information, by recourse to an information theory based inference approach.

Casas, M.; Plastino, A.; Puente, A. (Physics Department, National University La Plata, CC67, 1900 La Plata (Argentina) Departament di Fisica, Universitat de les Illes Balears, 07071 Palma de Mallorca (Spain))

1993-08-01

108

Simulation of wind wave growth with reference source functions

NASA Astrophysics Data System (ADS)

We present results of extensive simulations of wind wave growth with the so-called reference source function in the right-hand side of the Hasselmann equation written as follows First, we use Webb's algorithm [8] for calculating the exact nonlinear transfer function Snl. Second, we consider a family of wind input functions in accordance with recent consideration [9] ( )s S = ?(k)N , ?(k) = ? ? ?- f (?). in k 0 ?0 in (2) Function fin(?) describes dependence on angle ?. Parameters in (2) are tunable and determine magnitude (parameters ?0, ?0) and wave growth rate s [9]. Exponent s plays a key role in this study being responsible for reference scenarios of wave growth: s = 4-3 gives linear growth of wave momentum, s = 2 - linear growth of wave energy and s = 8-3 - constant rate of wave action growth. Note, the values are close to ones of conventional parameterizations of wave growth rates (e.g. s = 1 for [7] and s = 2 for [5]). Dissipation function Sdiss is chosen as one providing the Phillips spectrum E(?) ~ ?5 at high frequency range [3] (parameter ?diss fixes a dissipation scale of wind waves) Sdiss = Cdiss?4w?N (k)?(? - ?diss) (3) Here frequency-dependent wave steepness ?2w = E(?,?)?5-g2 makes this function to be heavily nonlinear and provides a remarkable property of stationary solutions at high frequencies: the dissipation coefficient Cdiss should keep certain value to provide the observed power-law tails close to the Phillips spectrum E(?) ~ ?-5. Our recent estimates [3] give Cdiss ? 2.0. The Hasselmann equation (1) with the new functions Sin, Sdiss (2,3) has a family of self-similar solutions of the same form as previously studied models [1,3,9] and proposes a solid basis for further theoretical and numerical study of wave evolution under action of all the physical mechanisms: wind input, wave dissipation and nonlinear transfer. Simulations of duration- and fetch-limited wind wave growth have been carried out within the above model setup to check its conformity with theoretical predictions, previous simulations [2,6,9], experimental parameterizations of wave spectra [1,4] and to specify tunable parameters of terms (2,3). These simulations showed realistic spatio-temporal scales of wave evolution and spectral shaping close to conventional parameterizations [e.g. 4]. An additional important feature of the numerical solutions is a saturation of frequency-dependent wave steepness ?w in short-frequency range. The work was supported by the Russian government contract No.11.934.31.0035, Russian Foundation for Basic Research grant 11-05-01114-a and ONR grant N00014-10-1-0991. References [1] S. I. Badulin, A. V. Babanin, D. Resio, and V. Zakharov. Weakly turbulent laws of wind-wave growth. J. Fluid Mech., 591:339-378, 2007. [2] S. I. Badulin, A. N. Pushkarev, D. Resio, and V. E. Zakharov. Self-similarity of wind-driven seas. Nonl. Proc. Geophys., 12:891-946, 2005. [3] S. I. Badulin and V. E. Zakharov. New dissipation function for weakly turbulent wind-driven seas. ArXiv e-prints, (1212.0963), December 2012. [4] M. A. Donelan, J. Hamilton, and W. H. Hui. Directional spectra of wind-generated waves. Phil. Trans. Roy. Soc. Lond. A, 315:509-562, 1985. [5] M. A. Donelan and W. J. Pierson-jr. Radar scattering and equilibrium ranges in wind-generated waves with application to scatterometry. J. Geophys. Res., 92(C5):4971-5029, 1987. [6] E. Gagnaire-Renou, M. Benoit, and S. I. Badulin. On weakly turbulent scaling of wind sea in simulations of fetch-limited growth. J. Fluid Mech., 669:178-213, 2011. [7] R. L. Snyder, F. W. Dobson, J. A. Elliot, and R. B. Long. Array measurements of atmospheric pressure fluctuations above surface gravity waves. J. Fluid Mech., 102:1-59, 1981. [8] D. J. Webb. Non-linear transfers between sea waves. Deep Sea Res., 25:279-298, 1978. [9] V. E. Zakharov, D. Resio, and A. N. Pushkarev. New wind input term consistent with experimental, theoretical and numerical considerations. ArXiv e-prints, (1212.1069), December 2012.

Badulin, Sergei I.; Zakharov, Vladimir E.; Pushkarev, Andrei N.

2013-04-01

109

We derive variational equations for optimization of the orbitals of arbitrary multiconfiguration wave functions. Expressing the transformation matrix connecting the set of orthonormal trial vectors and the set of final optimal orbitals as an exponential matrix of independent rotation angles allows a simple derivation of the coupled variational equations to arbitrary order. We include the explicit results through third order

Laurence G. Yaffe; William A. Goddard III

1976-01-01

110

BackgroundIncreased arterial wave reflections predict cardiovascular events in dialysis patients. Their impact on the progression of renal disease has not been determined.MethodsWe prospectively quantified wave reflections as pressure augmentation (AP) and augmentation index (AIx) using radial applanation tonometry and a transfer function, in 111 patients (mean age 53.6 years; 71 men, 31 diabetics) with chronic kidney disease not requiring dialysis.

Thomas Weber; Marcus Ammer; Duygu Gündüz; Paul Bruckenberger; Bernd Eber; Manfred Wallner

2011-01-01

111

An analytical model to predict dune erosion due to wave impact

An analytical model is developed to calculate recession distance and eroded volume for coastal dunes during severe storms. The transport relationship used in the model is based on wave impact theory, where individual swash waves hitting the dune face induce the erosion. Combining this relationship with the sediment volume conservation equation describes the response of the dune to high waves

Magnus Larson; Li Erikson; Hans Hanson

2004-01-01

112

A critical survey of wave propagation and impact in composite materials

NASA Technical Reports Server (NTRS)

A review of the field of stress waves in composite materials is presented covering the period up to December 1972. The major properties of waves in composites are discussed and a summary is made of the major experimental results in this field. Various theoretical models for analysis of wave propagation in laminated, fiber and particle reinforced composites are surveyed. The anisotropic, dispersive and dissipative properties of stress pulses and shock waves in such materials are reviewed. A review of the behavior of composites under impact loading is presented along with the application of wave propagation concepts to the determination of impact stresses in composite plates.

Moon, F. C.

1973-01-01

113

NASA Astrophysics Data System (ADS)

The marine atmospheric boundary layer is strongly influenced by the moving surface in the presence of surface waves; the impact depends on the wave conditions and the interaction with the atmosphere. Previous studies using measurements as well as numerical simulations with large-eddy simulations have shown that surface waves propagating faster than the wind (swell) alter the surface exchange as well as turbulence properties in the atmosphere. This impact is here introduced in a coupled wave-atmosphere regional climate model with a so-called E - l turbulence scheme (where E is the turbulent kinetic energy and l is a mixing length). A wave age dependent coefficient (here called Wmix) is added to the mixing length in the turbulence parameterization. This acts similarly to inducing additional convection, with larger mixing length and increased eddy diffusivity, when we have near neutral stratification and strong swell. For shallow boundary layers the regional coupled climate model shows a larger response to the introduced wave coupling with increased near surface wind speed and smaller wind gradient between the surface and middle part of the boundary layer. The impact for the studied areas is relatively minor for parameters averaged over 1 year, but for limited periods and specific situations the impact is larger. One could expect a larger impact in areas with stronger swell dominance. We thus conclude that the impact of swell waves on the mixing in the boundary layer is not insignificant and should be taken into account when developing wave-atmosphere coupled regional climate models or global climate models.

Rutgersson, A.; Nilsson, E. O.; Kumar, R.

2012-11-01

114

Critical Analysis of the Density Functional Theory Prediction of Enhanced Capillary Waves

NASA Astrophysics Data System (ADS)

We present a critical analysis of the density functional description for capillary wave fluctuations on free liquid surfaces. The proposal made by Mecke and Dietrich, [Phys. Rev. EPLEEE81063-651X 59, 6766 (1999)10.1103/PhysRevE.59.6766], to obtain the effective wave vector dependent surface tension, and their prediction of an enhanced regime of capillary waves at mesoscopic scales, has had a large impact including claims of experimental observation [Fradin , Nature (London)NATUAS0028-0836 403, 871 (2000)10.1038/35002533; Mora , Phys. Rev. Lett.PRLTAO0031-9007 90, 216101 (2003)10.1103/PhysRevLett.90.216101]. Our analysis shows that there is a qualitative problem in the convergence of the low q expansion used for that prediction, and that the assumed link between the equilibrium density functional description of the liquid surface and its capillary wave fluctuations leads always to the unphysical decrease of the surface tension for large wave vectors.

Tarazona, P.; Checa, R.; Chacón, E.

2007-11-01

115

NASA Astrophysics Data System (ADS)

Numerical modeling of the Lamb wave propagation in functionally graded materials (FGMs) by a two-dimensional time-domain spectral finite element method (SpFEM) is presented. The high-order Chebyshev polynomials as approximation functions are used in the present formulation, which provides the capability to take into account the through thickness variation of the material properties. The efficiency and accuracy of the present model with one and two layers of 5th order spectral elements in modeling wave propagation in FGM plates are analyzed. Different excitation frequencies in a wide range of 28-350 kHz are investigated, and the dispersion properties obtained by the present model are verified by reference results. The through thickness wave structure of two principal Lamb modes are extracted and analyzed by the symmetry and relative amplitude of the vertical and horizontal oscillations. The differences with respect to Lamb modes generated in homogeneous plates are explained. Zero-crossing and wavelet signal processing-spectrum decomposition procedures are implemented to obtain phase and group velocities and their dispersion properties. So it is attested how this approach can be practically employed for simulation, calibration and optimization of Lamb wave based nondestructive evaluation techniques for the FGMs. The capability of modeling stress wave propagation through the thickness of an FGM specimen subjected to impact load is also investigated, which shows that the present method is highly accurate as compared with other existing reference data.

Hedayatrasa, Saeid; Bui, Tinh Quoc; Zhang, Chuanzeng; Lim, Chee Wah

2014-02-01

116

Impact force identification in aerospace panels by an inverse ultrasonic guided wave problem

NASA Astrophysics Data System (ADS)

This paper deals with monitoring impacts on aluminum and composite aerospace panels. The specific problems addressed are (1) the identification of the impact forces (force magnitude time history) and (2) the discrimination of "damaging impacts" from "non-damaging impacts." Ultrasonic guided waves generated by the impacts are used as the sensing mechanism. Flexible Macro-Fiber Composite (MFC) patches are used as the ultrasonic receivers. The impact force identification method is based on an optimization routine which minimizes the difference between the experimental impact waves and the numerical impact waves calculated by a Semi-Analytical Finite Element (SAFE) forced analysis. The differentiation of "damaging impacts" vs. "non-damaging impacts" is based on a frequency analysis of the impact waves. These techniques are demonstrated through an extensive experimental testing program involving the following six specimens: an aluminum panel, a quasi-isotropic CFRP composite panel, a highly anisotropic CFRP composite panel, a stiffened aluminum panel, a stiffened quasi-isotropic CFRP composite panel, and a stiffened anisotropic CFRP composite panel. These panels were subjected to low-velocity hammer impacts and to high-velocity gas-gun impacts by ice projectiles at speeds up to 170 m/sec using UCSD's gas-gun test facility. In all of these experiments, the techniques summarized above gave excellent results for both impact force identification and impact force discrimination.

Bartoli, Ivan; Salamone, Salvatore; Lanza di Scalea, Francesco; Rhymer, Jennifer; Kim, Hyonny

2011-03-01

117

Solitary transversal waves and vibro-impact motions in infinite chains and rods

This paper deals with traveling waves in non-linear infinite elastic systems (chains and rods). A passage to a long wavelength approximation is realized. Conditions of the solitary waves existence are analyzed. The waves with regard to elastic impacts have been investigated. 7 2000 Elsevier Science Ltd. All rights reserved. The study of non-linearities due to vibro-impacts is of significant practical

Yu V. Mikhlina; A. M. Volok

118

The impact of the summer 2003 heat wave in Iberia: how should we measure it?

We present a new approach to improve the reliability of quantifying the impact of a heat wave on mortality rates. We show,\\u000a for the recent European summer 2003 heat wave, that the use of absolute maximum temperature values, or number of days above\\u000a a given threshold, can be misleading. Here, we have assessed the impact of the heat wave on

J. Díaz; R. García-Herrera; R. M. Trigo; C. Linares; M. A. Valente; J. M. De Miguel; E. Hernández

2006-01-01

119

Quantum Canonical Tensor Model and AN Exact Wave Function

NASA Astrophysics Data System (ADS)

Tensor models in various forms are being studied as models of quantum gravity. Among them the canonical tensor model has a canonical pair of rank-three tensors as dynamical variables, and is a pure constraint system with first-class constraints. The Poisson algebra of the first-class constraints has structure functions, and provides an algebraically consistent way of discretizing the Dirac first-class constraint algebra for general relativity. This paper successfully formulates the Wheeler-DeWitt scheme of quantization of the canonical tensor model; the ordering of operators in the constraints is determined without ambiguity by imposing Hermiticity and covariance on the constraints, and the commutation algebra of constraints takes essentially the same form as the classical Poisson algebra, i.e. is first-class. Thus one could consistently obtain, at least locally in the configuration space, wave functions of "universe" by solving the partial differential equations representing the constraints, i.e. the Wheeler-DeWitt equations for the quantum canonical tensor model. The unique wave function for the simplest nontrivial case is exactly and globally obtained. Although this case is far from being realistic, the wave function has a few physically interesting features; it shows that locality is favored, and that there exists a locus of configurations with features of beginning of universe.

Sasakura, Naoki

2013-08-01

120

Deducing spectroscopic factors from wave-function asymptotics

In a coupled-channel model, we explore the effects of coupling between configurations on the radial behavior of the wave function and, in particular, on the spectroscopic factor (SF) and the asymptotic normalization coefficient (ANC). We evaluate the extraction of a SF from the ratio of the ANC of the coupled-channel model to that of a single-particle approximation of the wave function. We perform this study within a core+n collective model, which includes two states of the core that connect by a rotational coupling. To get additional insights, we also use a simplified model that takes a {delta} function for the coupling potential. Calculations are performed for {sup 11}Be. Fair agreement is obtained between the SF inferred from the single-particle approximation and the one obtained within the coupled-channel models. Significant discrepancies are observed only for large coupling strength and/or large admixture, that is, a small SF. This suggests that reliable SFs can be deduced from the wave-function asymptotics when the structure is dominated by one configuration, that is, for a large SF.

Capel, P. [Physique Quantique, C.P. 165/82, and Physique Nucleaire Theorique et Physique Mathematique, C.P. 229, Universite Libre de Bruxelles (ULB), B-1050 Brussels (Belgium); National Superconducting Cyclotron Laboratory and Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824 (United States); Danielewicz, P.; Nunes, F. M. [National Superconducting Cyclotron Laboratory and Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824 (United States)

2010-11-15

121

Configuration interaction wave functions: A seniority number approach

NASA Astrophysics Data System (ADS)

This work deals with the configuration interaction method when an N-electron Hamiltonian is projected on Slater determinants which are classified according to their seniority number values. We study the spin features of the wave functions and the size of the matrices required to formulate states of any spin symmetry within this treatment. Correlation energies associated with the wave functions arising from the seniority-based configuration interaction procedure are determined for three types of molecular orbital basis: canonical molecular orbitals, natural orbitals, and the orbitals resulting from minimizing the expectation value of the N-electron seniority number operator. The performance of these bases is analyzed by means of numerical results obtained from selected N-electron systems of several spin symmetries. The comparison of the results highlights the efficiency of the molecular orbital basis which minimizes the mean value of the seniority number for a state, yielding energy values closer to those provided by the full configuration interaction procedure.

Alcoba, Diego R.; Torre, Alicia; Lain, Luis; Massaccesi, Gustavo E.; Oña, Ofelia B.

2014-06-01

122

Laughlin wave function and one-dimensional free fermions

Making use of the well-known phase-space reduction in the lowest Landau level, we show that the Laughlin wave function for the {nu}=1/{ital m} case can be obtained exactly as a coherent-state representation of a one-dimensional (1D) wave function. The 1D system consists of {ital m} copies of free fermions associated with each of the {ital N} electrons, confined in a common harmonic well potential. Interestingly, the condition for this exact correspondence is found to incorporate Jain`s parton picture. We argue that this correspondence between the free fermions and quantum Hall effect is due to the mapping of the 1D system under consideration to the Gaussian unitary ensemble in the random matrix theory.

Panigrahi, P.K.; Sivakumar, M. [School of Physics, University of Hyderabad, Hyderabad-500 134 (India)] [School of Physics, University of Hyderabad, Hyderabad-500 134 (India)

1995-11-15

123

Analytical wave functions for atomic quantum-defect theory

We present an exactly solvable effective potential that reproduces atomic spectra in the limit of exact quantum-defect theory, i.e., the limit in which, for a fixed l, the principal quantum number is modified by a constant: n*=n-delta(l). Transition probabilities for alkali atoms are calculated using the analytical wave functions obtained and agree well with accepted values. This allows us to

V. Alan Kostelecký; Michael Martin Nieto

1985-01-01

124

Interpreting the Quantum Wave Function in Terms of 'Interacting Faculties'

In this article we discuss the problem of finding an interpretation of\\u000aquantum mechanics which provides an objective account of physical reality. In\\u000athe first place we discuss the problem of interpretation and analyze the\\u000aimportance of such an objective account in physics. In this context we present\\u000athe problems which arise when interpreting the quantum wave function within the

Christian de Ronde

2007-01-01

125

Density functional perturbation theory within the projector augmented wave method

Density functional perturbation theory (DFPT) with ultrasoft pseudopotentials (US-PPs) is extended to the projector augmented wave (PAW) method. I show that minor modifications of the existing DFPT codes for US-PPs are sufficient for dealing with PAW. A few applications to small molecules (CO, H2O ) and to ferromagnetic Fe in the body-centered cubic structure validate the theory. Bibtex entry for

Andrea Dal Corso

2010-01-01

126

Computations of hypervelocity impact using the CTH shock wave physics code

Computer simulations of several hypervelocity impact events using the multi-dimensional, multi-material CTH shock wave physics code are presented and discussed. First, some two-dimensional CTH calculations are presented. These are then compared with calculations using another Eulerian shock wave physics code (CSQ) and with flash X-ray photographs of the impact events. Fully three-dimensional computations, including simulations of oblique impacts, are then

Frederick J. Zeigler; J. Michael McGlaun; Samuel L. Thompson; Timothy G. Trucano

1987-01-01

127

An analytical expression for the log-amplitude correlation function based on the Rytov approximation is derived for spherical wave propagation through an anisotropic non-Kolmogorov refractive turbulent atmosphere. The expression reduces correctly to the previously published analytic expressions for the case of spherical wave propagation through isotropic Kolmogorov turbulence. These results agree well with a wave-optics simulation based on the more general Fresnel approximation, as well as with numerical evaluations, for low-to-moderate strengths of turbulence. These results are useful for understanding the potential impact of deviations from the standard isotropic Kolmogorov spectrum. PMID:24561950

Gudimetla, V S Rao; Holmes, Richard B; Riker, Jim F

2014-01-01

128

An analytical expression for the log-amplitude correlation function for plane wave propagation through anisotropic non-Kolmogorov turbulent atmosphere is derived. The closed-form analytic results are based on the Rytov approximation. These results agree well with wave optics simulation based on the more general Fresnel approximation as well as with numerical evaluations, for low-to-moderate strengths of turbulence. The new expression reduces correctly to the previously published analytic expressions for the cases of plane wave propagation through both nonisotropic Kolmogorov turbulence and isotropic non-Kolmogorov turbulence cases. These results are useful for understanding the potential impact of deviations from the standard isotropic Kolmogorov spectrum. PMID:23455912

Gudimetla, V S Rao; Holmes, Richard B; Riker, Jim F

2012-12-01

129

S-wave velocity structure in southwest China from surface wave tomography and receiver functions

NASA Astrophysics Data System (ADS)

Using the surface wave records of 504 teleseismic events at 50 temporal and 92 permanent seismic stations in southwest China, we extracted the phase velocity dispersion curves with interstation correlation method, and obtained the phase velocity maps at 10, 15, 25, 40, 60 and 75 s with a grid space of 0.5×0.5 from surface wave tomography. Meanwhile, we obtained the S-wave velocity structures beneath three profiles from the joint inversion of receiver functions and surface waves. From the maps at short periods (10 and 15 s) and long periods (40, 60 and 75 s), different distribution features of high velocity zones (HVZs for short) and low velocity zones (LVZs for short) are shown in the study area: HVZs at short periods are shown in the Panzhihua - Emeishan region, Sichuan basin and Weixi-Lijiang region, surrounding the LVZs from Songpan-Ganzi block to the east of Lijiang where there are significant higher elevations; whereas HVZs at long periods are shown in the Weixi-Lijiang region, Panzhihua-Chuxiong basin and Kunming-Tonghai region and forming a line in the center part of the study area, and the fast polarization directions of the shear wave from SKS analysis on the two sides of the line change significantly. These phenomena indicate plateau material flow can be blocked in two different depth intervals and leads to different horizontal extensions. From the maps at long periods and the structures along the profiles, LVZs are shown in the upper mantle beneath rapid slip fault zones, such as Anninghe - Zemuhe - Xiaojiang fault zone, Red River fault zone and Xiaojinhe fault zone, implying these faults are deep penetrating faults. Figure (a-f) Rayleigh wave phase velocity maps at 10, 15, 25,40,60 and 75 s with a resolution of 100 km. The black lines represent faults. The red points represent M?6 earthquakes. The colour scale changes in different panels. Figure (g) Distribution of the seismic stations and regional tectonic features in the study area. Figure (h-j) The S wave velocity structures beneath the profiles AA', BB' and CC' from the joint inversion of receiver functions and surface waves. The results at different stations are vertically projected to the profiles.

Wang, W.; Wu, J.; Fang, L.; Lai, G.; Yang, T.

2013-12-01

130

Statistical properties and correlation functions for drift waves

The dissipative one-field drift wave equation is solved using the pseudospectral method to generate steady-state fluctuations. The fluctuations are analyzed in terms of space-time correlation functions and modal probability distributions. Nearly Gaussian statistics and exponential decay of the two-time correlation functions occur in the presence of electron dissipation, while in the absence of electron dissipation long-lived vortical structures occur. Formulas from renormalized, Markovianized statistical turbulence theory are given in a local approximation to interpret the dissipative turbulence.

Horton, W.

1986-05-01

131

The impact of heat waves on children's health: a systematic review.

Young children are thought to be particularly sensitive to heat waves, but relatively less research attention has been paid to this field to date. A systematic review was conducted to elucidate the relationship between heat waves and children's health. Literature published up to August 2012 were identified using the following MeSH terms and keywords: "heatwave", "heat wave", "child health", "morbidity", "hospital admission", "emergency department visit", "family practice", "primary health care", "death" and "mortality". Of the 628 publications identified, 12 met the selection criteria. The existing literature does not consistently suggest that mortality among children increases significantly during heat waves, even though infants were associated with more heat-related deaths. Exposure to heat waves in the perinatal period may pose a threat to children's health. Pediatric diseases or conditions associated with heat waves include renal disease, respiratory disease, electrolyte imbalance and fever. Future research should focus on how to develop a consistent definition of a heat wave from a children's health perspective, identifying the best measure of children's exposure to heat waves, exploring sensitive outcome measures to quantify the impact of heat waves on children, evaluating the possible impacts of heat waves on children's birth outcomes, and understanding the differences in vulnerability to heat waves among children of different ages and from different income countries. Projection of the children's disease burden caused by heat waves under climate change scenarios, and development of effective heat wave mitigation and adaptation strategies that incorporate other child protective health measures, are also strongly recommended. PMID:23525899

Xu, Zhiwei; Sheffield, Perry E; Su, Hong; Wang, Xiaoyu; Bi, Yan; Tong, Shilu

2014-03-01

132

The variational co-detor method has been applied to calculate wave functions and energies for the P2 and S2 states of Cl, the S1 state of Cl-, the P3, D1, S1 and P03 states of S and the P2 state of S-. This is the first application of the method to atoms of the second chemical period, and is thus an

S. F. Boys; V. E. Price

1954-01-01

133

A wave propagation model for the high velocity impact response of a composite sandwich panel

A solution methodology to predict the residual velocity of a hemispherical-nose cylindrical projectile impacting a composite sandwich panel at high velocity is presented. The term high velocity impact is used to describe impact scenarios where the projectile perforates the panel and exits with a residual velocity. The solution is derived from a wave propagation model involving deformation and failure of

Michelle S. Hoo Fatt; Dushyanth Sirivolu

2010-01-01

134

Projector augmented-wave method: Application to relativistic spin-density functional theory

Applying the projector augmented-wave (PAW) method to relativistic spin-density functional theory (RSDFT) we derive PAW Dirac-Kohn-Sham equations for four-component spinor pseudo-wave-functions. The PAW freedom to add a vanishing operator inside the PAW spheres allows us to transform these PAW Dirac-type equations into PAW Pauli-type equations for two-component spinor pseudo-wave-functions. With these wave functions, we get the frozen-core energy as well

Andrea Dal Corso

2010-01-01

135

Ramp wave generation using graded areal density ceramic flyers and the plate impact technique

NASA Astrophysics Data System (ADS)

A requirement exists to generate realistic insults in energetic targets, for example ramp loadings leading to shock waves. This paper examines the development of a ceramic flyer ramp wave generation technique. Ceramic stereolithography was used to produce fully-dense, graded areal density alumina ceramic flyers. These flyers consisted of multiple square pyramids arranged on a solid base. The gas gun plate impact and electromagnetic particle velocity gauge techniques were used to observe the ramp waves generated when the flyers impacted a Kel-F 81 polymer target. Ramp waves of varying properties were successfully generated in the targets, and good agreement was obtained with 3D hydrocode modelling.

Taylor, P.; Goff, M.; Hazell, P. J.; Leighs, J.; Wood, D.; Appleby-Thomas, G. J.

2014-05-01

136

An efficient procedure for the development of optimized Projector Augmented Wave basis functions

In the Projector Augmented Wave (PAW) method, a local potential, basis functions, and projector functions form an All-Electron (AE) basis for valence wave functions in the application of Density Functional Theory (DFT). The construction of these potentials, basis functions and projector functions for each element can be complex, and several codes capable of utilizing the PAW method have been otherwise

R. J. Snow; A. F. Wright; C. Y. Fong

2010-01-01

137

Love wave propagation in functionally graded piezoelectric material layer.

An exact approach is used to investigate Love waves in functionally graded piezoelectric material (FGPM) layer bonded to a semi-infinite homogeneous solid. The piezoelectric material is polarized in z-axis direction and the material properties change gradually with the thickness of the layer. We here assume that all material properties of the piezoelectric layer have the same exponential function distribution along the x-axis direction. The analytical solutions of dispersion relations are obtained for electrically open or short circuit conditions. The effects of the gradient variation of material constants on the phase velocity, the group velocity, and the coupled electromechanical factor are discussed in detail. The displacement, electric potential, and stress distributions along thickness of the graded layer are calculated and plotted. Numerical examples indicate that appropriate gradient distributing of the material properties make Love waves to propagate along the surface of the piezoelectric layer, or a bigger electromechanical coupling factor can be obtained, which is in favor of acquiring a better performance in surface acoustic wave (SAW) devices. PMID:17107699

Du, Jianke; Jin, Xiaoying; Wang, Ji; Xian, Kai

2007-03-01

138

Multiconfigurational floating Gaussian electronic wave functions are obtained for a variety of 2-electron atoms and for H2. These correlated wave functions are unusual in that they are constructed without taking excitations from a reference configuration. The description of electron correlation, the degree to which the proper ground state symmetry is attained, and the behavior of wave functions obtained by simulated

Dario A. Estrin; Chiachin Tsoo; Sherwin J. Singer

1990-01-01

139

Propagation of impact-induced shock waves in porous sandstone using mesoscale modeling

NASA Astrophysics Data System (ADS)