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1

Adaptive multiconfigurational wave functions  

SciTech Connect

A method is suggested to build simple multiconfigurational wave functions specified uniquely by an energy cutoff ?. These are constructed from a model space containing determinants with energy relative to that of the most stable determinant no greater than ?. The resulting ?-CI wave function is adaptive, being able to represent both single-reference and multireference electronic states. We also consider a more compact wave function parameterization (?+SD-CI), which is based on a small ?-CI reference and adds a selection of all the singly and doubly excited determinants generated from it. We report two heuristic algorithms to build ?-CI wave functions. The first is based on an approximate prescreening of the full configuration interaction space, while the second performs a breadth-first search coupled with pruning. The ?-CI and ?+SD-CI approaches are used to compute the dissociation curve of N{sub 2} and the potential energy curves for the first three singlet states of C{sub 2}. Special attention is paid to the issue of energy discontinuities caused by changes in the size of the ?-CI wave function along the potential energy curve. This problem is shown to be solvable by smoothing the matrix elements of the Hamiltonian. Our last example, involving the Cu{sub 2}O{sub 2}{sup 2+} core, illustrates an alternative use of the ?-CI method: as a tool to both estimate the multireference character of a wave function and to create a compact model space to be used in subsequent high-level multireference coupled cluster computations.

Evangelista, Francesco A., E-mail: francesco.evangelista@emory.edu [Department of Chemistry and Cherry L. Emerson Center for Scientific Computation, Emory University, Atlanta, Georgia 30322 (United States)

2014-03-28

2

Comparing ab initio density-functional and wave function theories: the impact of correlation on the electronic density and the role of the correlation potential.  

PubMed

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

3

Wave Function Optimization in QMCPACK  

NASA Astrophysics Data System (ADS)

Wave function optimization is essential for both the accuracy and efficiency of diffusion, reptation, and variational quantum Monte Carlo (QMC). In this talk we outline the wave function optimization strategy used in the QMC software package QMCPACK developed at the University of Illinois. We use an extension of the linear optimization method originally developed by Umrigar et. al.[1] to optimize parameters in Slater-Jastrow, multi-determinant Slater-Jastrow, and Backflow-Jastrow trial wave functions. The efficiency and accuracy of this method is presented for bulk Silicon, Jellium, and the Nitrogen dimer.[4pt] [1] Umrigar et al. PRL 98, 110201 (2007)

McMinis, Jeremy; Morales, Miguel; Kim, Jeongnim; Ceperley, David

2011-03-01

4

Wave impacts: experimental and numerical research Introduction  

E-print Network

and Waves) department in Deltares is currently looking for a student that is willing to perform his/her MSc on a vertical wall have been conducted in the 250m long Delta flume of Deltares. This kind of wave impacts can also Figure 2. Deltares wants to investigate its quality for wave impact problems. Figure 2. Snapshots

Vuik, Kees

5

Wave-function functionals for the density  

SciTech Connect

We extend the idea of the constrained-search variational method for the construction of wave-function functionals {psi}[{chi}] of functions {chi}. The search is constrained to those functions {chi} such that {psi}[{chi}] reproduces the density {rho}(r) while simultaneously leading to an upper bound to the energy. The functionals are thereby normalized and automatically satisfy the electron-nucleus coalescence condition. The functionals {psi}[{chi}] are also constructed to satisfy the electron-electron coalescence condition. The method is applied to the ground state of the helium atom to construct functionals {psi}[{chi}] that reproduce the density as given by the Kinoshita correlated wave function. The expectation of single-particle operators W={Sigma}{sub i}r{sub i}{sup n}, n=-2,-1,1,2, W={Sigma}{sub i}{delta}(r{sub i}) are exact, as must be the case. The expectations of the kinetic energy operator W=-(1/2){Sigma}{sub i}{nabla}{sub i}{sup 2}, the two-particle operators W={Sigma}{sub n}u{sup n}, n=-2,-1,1,2, where u=|r{sub i}-r{sub j}|, and the energy are accurate. We note that the construction of such functionals {psi}[{chi}] is an application of the Levy-Lieb constrained-search definition of density functional theory. It is thereby possible to rigorously determine which functional {psi}[{chi}] is closer to the true wave function.

Slamet, Marlina; Pan Xiaoyin; Sahni, Viraht [Sacred Heart University, Fairfield, Connecticut 06825 (United States); Faculty of Science, Ningbo University, 315211 Ningbo (China); Brooklyn College and The Graduate School of the City University of New York, New York, New York 10016 (United States)

2011-11-15

6

Conductance of a copper-nanotube bundle interface: Impact of interface geometry and wave-function interference  

Microsoft Academic Search

Carbon nanotubes (CNTs) are a promising candidate to replace copper interconnects. An ab initio study is presented on the conductance of a closed-packed bundle of very narrow metallic (4,0) CNTs, which is vertically placed on a Cu (100) surface. The intertube interactions have no significant impact on the conductance. The conductance is highly dependent on the exact geometry of the

Steven Compernolle; Geoffrey Pourtois; Bart Sorée; Wim Magnus; Liviu F. Chibotaru; Arnout Ceulemans

2008-01-01

7

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

8

Impact produced stress waves in composites  

SciTech Connect

The Nonhomogenized Dynamic Method of Cells (NHDMOC) is used to study the propagation of stress waves through laminates. The accuracy of the theory is tested by applying it to a plate-impact experiment and checking its ability to resolve a propagation shock wave front. The theory is then compared to Lagrangian hydrodynamic calculations, where it is found that the NHDMOC consistently requires less fine spatial and temporal grids, and less artificial viscosity to control numerical noise. The theory is then used to treat the impact of an epoxy-graphite bilaminate. When the viscoelastic properties of the epoxy are accounted for, the theory agrees well with the experiment.

Clements, B.; Johnson, J.; Addessio, F.; Hixson, R.

1997-05-01

9

Wave impact on a deck or baffle  

NASA Astrophysics Data System (ADS)

Some coastal or ocean structures have deck-like baffles or horizontal platforms that can be exposed to wave action in heavy seas. A similar situation may occur in partially-filled tanks with horizontal baffles that become engulfed by sloshing waves. This can result in dangerous wave impact loads (slamming) causing a rapid rise of pressures which may lead to local damaging by crack initiation and/or propagation. We consider the wave impact against the whole of underside of horizontal deck (or baffle) projecting from a seawall (or vertical tank wall), previously studied by Wood and Peregrine (1996) using a different method based on conformal mappings. The approach used is to simplify the highly time-dependent and very nonlinear problem by considering the time integral of the pressure over the duration of the impact pressure-impulse, P (x, y). Our method expresses this in terms of eigenfunctions that satisfy the boundary conditions apart from that on the impact region and the matching of the two regions (under the platform and under the free surface); this results in a matrix equation to be solved numerically. As in Wood and Peregrine, we found that the pressure impulse on the deck increases when the length of deck increases, there is a strong pressure gradient beneath the deck near the seaward edge and the maximum pressure impulse occurs at the landward end of the impact zone.

Md Noar, Nor Aida Zuraimi; Greenhow, Martin

2015-02-01

10

Transoceanic infragravity waves impacting Antarctic ice shelves  

NASA Astrophysics Data System (ADS)

Long-period oceanic infragravity (IG) waves (ca. [250, 50] s period) are generated along continental coastlines by nonlinear wave interactions of storm-forced shoreward propagating swell. Seismic observations on the Ross Ice Shelf show that free IG waves generated along the Pacific coast of North America propagate transoceanically to Antarctica, where they induce a much higher amplitude shelf response than ocean swell (ca. [30, 12] s period). Additionally, unlike ocean swell, IG waves are not significantly damped by sea ice, and thus impact the ice shelf throughout the year. The response of the Ross Ice Shelf to IG-wave induced flexural stresses is more than 60 dB greater than concurrent ground motions measured at nearby Scott Base. This strong coupling suggests that IG-wave forcing may produce ice-shelf fractures that enable abrupt disintegration of ice shelves that are also affected by strong surface melting. Bolstering this hypothesis, each of the 2008 breakup events of the Wilkins Ice Shelf coincides with wave-model-estimated arrival of IG-wave energy from the Patagonian coast.

Bromirski, Peter D.; Sergienko, Olga V.; MacAyeal, Douglas R.

2010-01-01

11

Stress Wave Source Characterization: Impact, Fracture, and Sliding Friction  

NASA Astrophysics Data System (ADS)

Rapidly varying forces, such as those associated with impact, rapid crack propagation, and fault rupture, are sources of stress waves which propagate through a solid body. This dissertation investigates how properties of a stress wave source can be identified or constrained using measurements recorded at an array of sensor sites located far from the source. This methodology is often called the method of acoustic emission and is useful for structural health monitoring and the noninvasive study of material behavior such as friction and fracture. In this dissertation, laboratory measurements of 1--300 mm wavelength stress waves are obtained by means of piezoelectric sensors which detect high frequency (10 kHz--3MHz) motions of a specimen's surface, picometers to nanometers in amplitude. Then, stress wave source characterization techniques are used to study ball impact, drying shrinkage cracking in concrete, and the micromechanics of stick-slip friction of Poly(methyl methacrylate) (PMMA) and rock/rock interfaces. In order to quantitatively relate recorded signals obtained with an array of sensors to a particular stress wave source, wave propagation effects and sensor distortions must be accounted for. This is achieved by modeling the physics of wave propagation and transduction as linear transfer functions. Wave propagation effects are precisely modeled by an elastodynamic Green's function, sensor distortion is characterized by an instrument response function, and the stress wave source is represented with a force moment tensor. These transfer function models are verified though calibration experiments which employ two different mechanical calibration sources: ball impact and glass capillary fracture. The suitability of the ball impact source model, based on Hertzian contact theory, is experimentally validated for small (˜1 mm) balls impacting massive plates composed of four different materials: aluminum, steel, glass, and PMMA. Using this transfer function approach and the two mechanical calibration sources, four types of piezoelectric sensors were calibrated: three commercially available sensors and the Glaser-type conical piezoelectric sensor, which was developed in the Glaser laboratory. The distorting effects of each sensor are modeled using autoregressive-moving average (ARMA) models, and because vital phase information is robustly incorporated into these models, they are useful for simulating or removing sensor-induced distortions, so that a displacement time history can be retrieved from recorded signals. The Glaser-type sensor was found to be very well modeled as a unidirectional displacement sensor which detects stress wave disturbances down to about 1 picometer in amplitude. Finally, the merits of a fully calibrated experimental system are demonstrated in a study of stress wave sources arising from sliding friction, and the relationship between those sources and earthquakes. A laboratory friction apparatus was built for this work which allows the micro-mechanisms of friction to be studied with stress wave analysis. Using an array of 14 Glaser-type sensors, and precise models of wave propagation effects and the sensor distortions, the physical origins of the stress wave sources are explored. Force-time functions and focal mechanisms are determined for discrete events found amid the "noise" of friction. These localized events are interpreted to be the rupture of micrometer-sized contacts, known as asperities. By comparing stress wave sources from stick-slip experiments on plastic/plastic and rock/rock interfaces, systematic differences were found. The rock interface produces very rapid (<1 microsecond) implosive forces indicative of brittle asperity failure and fault gouge formation, while rupture on the plastic interface releases only shear force and produces a source more similar to earthquakes commonly recorded in the field. The difference between the mechanisms is attributed to the vast differences in the hardness and melting temperatures of the two materials, which affect the distribution of asp

McLaskey, Gregory Christofer

12

The wave function of quantum de Sitter  

NASA Astrophysics Data System (ADS)

We consider quantum general relativity in three dimensions with a positive cosmological constant. The Hartle-Hawking wave function is computed as a function of metric data at asymptotic future infinity. The analytic continuation from Euclidean Anti-de Sitter space provides a natural integration contour in the space of metrics, allowing us — with certain assumptions — to compute the wave function exactly, including both perturbative and non-perturbative effects. The resulting wave function is a non-normalizable function of the conformal structure of future infinity which is infinitely peaked at geometries where I+ becomesinfinitelyanisotropic. Weinterpretthisasanon-perturbativeinstabilityofde Sitter space in three dimensional Einstein gravity.

Castro, Alejandra; Maloney, Alexander

2012-11-01

13

Love waves in functionally graded piezoelectric materials  

Microsoft Academic Search

To investigate the features of Love waves in a layered functionally graded piezoelectric structure, the mathematical model is established on the basis of the elastic wave theory, and the WKB method is applied to solve the coupled electromechanical field differential equation. The solutions of the mechanical displacement and electrical potential function are obtained for the piezoelectric layer and elastic substrate.

X. Y. Li; Z. K. Wang; S. H. Huang

2004-01-01

14

Meson wave function from holographic models  

SciTech Connect

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

15

Impact damage detection in composite panels using guided ultrasonic waves  

NASA Astrophysics Data System (ADS)

Composite materials such as carbon fiber reinforced panels offer many 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 breakage or delaminations can be induced which reduce the functionality of the structure. Efficient structural health monitoring of such plate-like components can be achieved using guided ultrasonic waves propagating along the structure and covering critical areas. However, the guided wave propagation in such anisotropic and inhomogeneous materials needs to be understood from theory and verified experimentally to achieve sufficient coverage of the structure. Using noncontact laser interferometer measurements the guided wave propagation in carbon fiber reinforced panels was investigated experimentally. Good agreement with calculations using a full three-dimensional Finite Element (FE) model was achieved. Impact damage was induced in the composite panels and the guided wave scattering at the damage measured and quantified. Good agreement with predictions was found and barely visible impact damage in composite panels detected.

Murat, Bibi Intan Suraya; Khalili, Pouyan; Fromme, Paul

2014-02-01

16

Spatial wave functions of photon and electron  

SciTech Connect

The quantum mechanical model of the photon and electron is considered. The photon is conceived of as a particle moving with the speed of light which is accompanied by the wave function of the photon spreading out with an infinite speed. The wave function of the electron is introduced in terms of virtual photons tied to the electron. A description of electrostatic and magnetostatic interactions is given through the wave functions of electrons. The approach provides an explanation of the results of recent experiments measuring the speed of propagation of the bound magnetic field.

Khokhlov, D. L. [Sumy State University, R.-Korsakov St. 2, Sumy 40007 (Ukraine)

2010-12-01

17

Impact of stream restoration on flood waves  

NASA Astrophysics Data System (ADS)

Restoration of channelized or incised streams has the potential to reduce downstream flooding via storing and dissipating the energy of flood waves. Restoration design elements such as restoring meanders, reducing slope, restoring floodplain connectivity, re-introducing in-channel woody debris, and re-vegetating banks and the floodplain have the capacity to attenuate flood waves via energy dissipation and channel and floodplain storage. Flood discharge hydrographs measured up and downstream of several restored reaches of varying stream order and located in both urban and rural catchments are coupled with direct measurements of stream roughness at various stages to directly measure changes to peak discharge, flood wave celerity, and dispersion. A one-dimensional unsteady flow routing model, HEC-RAS, is calibrated and used to compare attenuation characteristics between pre and post restoration conditions. Modeled sensitivity results indicate that a restoration project placed on a smaller order stream demonstrates the highest relative reduction in peak discharge of routed flood waves compared to one of equal length on a higher order stream. Reductions in bed slope, extensions in channel length, and increases in channel and floodplain roughness follow restoration placement with the watershed in relative importance. By better understanding how design, scale, and location of restored reaches within a catchment hydraulically impact flood flows, this study contributes both to restoration design and site decision making. It also quantifies the effect of reach scale stream restoration on flood wave attenuation.

Sholtes, J.; Doyle, M.

2008-12-01

18

(e,2e) simple ionization of CO2 by fast electron impact: use of three-center parameterized continuum wave function and Dyson orbitals  

NASA Astrophysics Data System (ADS)

The variation of the triple differential cross section of the (e,2e) simple ionization of CO2 with the direction of the ejected electron is studied. The calculations are performed in the frame of a perturbative first Born procedure, using a three-center Dyson type description for the 1?g bound electron and an approximate three-center continuum solution of the corresponding Schrödinger equation for a specific wave vector {{{k}}e} for the free ejected electron, which satisfies the correct asymptotic boundary condition up to the order O({{(kr)}-2}). Empirical values for the screening of the three nuclei of the target and for the Sommerfeld parameters of the three-center Coulomb continuum function are introduced. The results are compared to existing experimental results and a theoretical result obtained by the same approach, using a Hartree–Fock Slater type orbital.

Alwan, O.; Chuluunbaatar, O.; Assfeld, X.; Naja, A.; Joulakian, B. B.

2014-11-01

19

The Maxwell wave function of the photon  

E-print Network

James Clerk Maxwell unknowingly discovered a correct relativistic, quantum theory for the light quantum, forty-three years before Einstein postulated the photon's existence. In this theory, the usual Maxwell field is the quantum wave function for a single photon. When the non-operator Maxwell field of a single photon is second quantized, the standard Dirac theory of quantum optics is obtained. Recently, quantum-state tomography has been applied to experimentally determine photon wave functions.

M. G. Raymer; Brian J. Smith

2006-04-24

20

Time symmetry in wave function collapse models  

E-print Network

A framework for wave function collapse models that is symmetric under time reversal is presented. Within this framework there are equivalent pictures of collapsing wave functions evolving in both time directions. The backwards-in-time Born rule can be broken by an initial condition on the Universe resulting in asymmetric behaviour. Similarly the forwards-in-time Born rule can in principle be broken by a final condition on the Universe.

Daniel Bedingham

2015-02-25

21

The geometry of electron wave functions  

SciTech Connect

To each wave function we assign a codimension-two submanifold in Euclidean space. We study the case of the wave function of a single electron in the hydrogen atom or other hydrogen-type atoms with quantum numbers n, l, m in detail. We prove theorems describing the behaviour of the scalar and sectional curvature of the constructed submanifold, depending on the quantum numbers. We also consider the external geometry of the submanifold. Bibliography: 9 titles.

Aminov, Yurii A [B.Verkin Institute for Low Temperature Physics and Engineering, National Academy of Sciences of Ukraine, Khar'kov (Ukraine)] [B.Verkin Institute for Low Temperature Physics and Engineering, National Academy of Sciences of Ukraine, Khar'kov (Ukraine)

2013-02-28

22

Light-cone wave functions of mesons  

E-print Network

A review of light-cone, covariant and gauge-invariant wave-functions of mesons is presented. They are basic non-perturbative objects needed for hard exclusive processes and for the method of light-cone QCD sum rules. The emphasis is on the vector mesons and a new (model-independent) way of computing the mass corrections of vector-meson wave functions is given.

G. Stoll

1999-04-29

23

Impact-driven shock waves and thermonuclear neutron generation  

NASA Astrophysics Data System (ADS)

Impact-driven shock waves, thermonuclear plasma and neutron yield were investigated. The results of 2D numerical simulations and Gekko/HIPER laser experiments on the collision of a laser-accelerated disk-projectile with a massive target, both containing (CD)n-material, are discussed. A two-temperature model of the non-equilibrium plasma created by impact-driven shock waves due to the collision of a laser-accelerated planar projectile with a massive target was developed and used for analysis of the numerical and experimental results. The model defines the characteristics of shock waves and plasmas (including their lifetime) as well as neutron yields in both the colliding objects as functions of velocity, density and mass of the projectile-impactor just before collision. The neutron yield generated during the period of laser-driven acceleration of the impactor was also determined. Two effects were discovered that exert a substantial influence on the plasma parameters and neutron yield. The first of them relates to the formation of the pre-impact state of the impactor. It decreases the projectile density due to thermal expansion of its matter through a free boundary during the period of laser-driven acceleration. The other relates to the formation of impact-produced plasma. Predominant heating of the ion component of plasma leads to the existence of a non-equilibrium two-temperature plasma during the period of electron-ion relaxation.

Gus'kov, S. Yu; Azechi, H.; Demchenko, N. N.; Doskoch, I. Ya; Murakami, M.; Rozanov, V. B.; Sakaiya, T.; Watari, T.; Zmitrenko, N. V.

2009-09-01

24

von Neumann-Landau equation for wave functions, wave-particle duality and collapses of wave functions  

E-print Network

It is shown that von Neumann-Landau equation for wave functions can present a mathematical formalism of motion of quantum mechanics. The wave functions of von Neumann-Landau equation for a single particle are `bipartite', in which the associated Schr\\"{o}dinger's wave functions correspond to those `bipartite' wave functions of product forms. This formalism establishes a mathematical expression of wave-particle duality and that von Neumann's entropy is a quantitative measure of complementarity between wave-like and particle-like behaviors. Furthermore, this extension of Schr\\"{o}dinger's form suggests that collapses of Schr\\"{o}dinger's wave functions can be regarded as the simultaneous transition of the particle from many levels to one.

Zeqian Chen

2007-09-29

25

Twist-2 Light-Cone Pion Wave Function  

E-print Network

We present an analysis of the existing constraints for the twist-2 light-cone pion wave function. We find that existing information on the pion wave function does not exclude the possibility that the pion wave function attains its asymptotic form. New bounds on the parameters of the pion wave function are presented.

V. M. Belyaev; Mikkel B. Johnson

1997-06-16

26

Spectroscopic measurement of an atomic wave function  

NASA Astrophysics Data System (ADS)

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.; Qamar, Shahid; Zubairy, M. Suhail

2003-02-01

27

The wave function of a gravitating shell  

E-print Network

We have calculated a discrete spectrum and found an exact analytical solution in the form of Meixner polynomials for the wave function of a thin gravitating shell in the Reissner-Nordstrom geometry. We show that there is no extreme state in the quantum spectrum of the gravitating shell, as in the case of extreme black hole.

V. I. Dokuchaev; S. V. Chernov

2010-10-01

28

The puzzling entanglement of Schrödinger's wave function  

NASA Astrophysics Data System (ADS)

A brief review of the conceptual difficulties met by the quantum formalism is presented. The main attempts to overcome these difficulties are considered and their limitations are pointed out. A recent proposal based on the assumption of the occurrence of a specific type of wave function collapse is discussed and its consequences for the above-mentioned problems are analyzed.

Ghirardi, G. C.; Rimini, A.; Weber, T.

1988-01-01

29

STUDY OF BLAST WAVE IMPACT ON CONCRETE AJIT GEEVARGHESE JOHN  

E-print Network

STUDY OF BLAST WAVE IMPACT ON CONCRETE by AJIT GEEVARGHESE JOHN Presented to the Faculty on numerous occasions to run my experiments. I would also express my gratitude to Kenneth without whom I would OF BLAST WAVE IMPACT ON CONCRETE Publication No. ______ Ajit Geevarghese John, M.S. The University of Texas

Texas at Arlington, University of

30

Designing electron wave functions in assembled nanostructures  

NASA Astrophysics Data System (ADS)

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 "quantum corrals". Precise control over the geometry of these structures allows electronic states to be tailored to suit particular experiments. Specifically, we design wave functions that enable studies of normally inaccessible quantum phases. First, we create pairs of quantum corrals with shapes drawn from contemporary mathematics. Exploiting special topological relationships between these structures, we retrieve internal quantum phase of electron wave functions without using interferometry. Second, we demonstrate that adding a single atom to a quantum corral can cause its electronic states to recombine into coherent superpositions. The real-space position of the additional atom controls abstract superposition phase angles, enabling arbitrary time-independent superpositions to be created. Third, we study geometric phase by creating a series of quantum corrals that traverse a closed path through a parameter space. Tracking the corral wave functions reveals a phase shift depending solely on the path taken, directly visualizing Berry's phase evolution in a quantum system. Finally, we extend beyond closed electron resonators and engineer wave functions in open nanostructures. We show that arbitrary patterns can be encoded into electronic states, creating a new form of holography on the nanoscale. We exhibit letters written in electron density rather than with atomic matter, and show that multiple letters may be simultaneously embedded at different energies in the same region of space. Because the wavelength of the electrons diminishes as energy is increased, this technique allows local information densities that exceed the conventionally assumed limit of 1 bit per atom. Taken together, the results in this thesis demonstrate unprecedented control of electron states in condensed matter and illuminate fundamental quantum phases that underlie systems ranging from coherent electronic devices to complex quantum materials.

Moon, Christopher Ryan

31

Wave functions for fractional Chern insulators  

NASA Astrophysics Data System (ADS)

We provide a parton construction of wave functions and effective field theories for fractional Chern insulators. We also analyze a strong-coupling expansion in lattice gauge theory that enables us to reliably map the parton gauge theory onto a microscopic electron Hamiltonian. We show that this strong-coupling expansion is useful because of a special hierarchy of energy scales in fractional quantum Hall physics. Our procedure is illustrated using the Hofstadter model and then applied to bosons at half filling and fermions at one-third filling in a checkerboard lattice model recently studied numerically. Because our construction provides a more or less unique mapping from microscopic model to effective parton description, we obtain wave functions in the same phase as the observed fractional Chern insulators without tuning any continuous parameters.

McGreevy, John; Swingle, Brian; Tran, Ky-Anh

2012-03-01

32

Spectroscopic measurement of an atomic wave function  

E-print Network

either tomographic or interferometric @11#. Ex- perimentally, tomographic method has been applied to the vibrational state of a diatomic molecule @12# and interfero- metric method for the holographic reconstruction of molecu- lar wave packets @13... on the measurement of Wigner function that bears a close connec- tion with the density operator of the system @3#, thus charac- terizing the quantum state completely. There are also several other techniques outside this tomographic @4,5# arena for measurement...

Kapale, KT; Qamar, S.; Zubairy, M. Suhail.

2003-01-01

33

Wave function methods for fractional electrons.  

PubMed

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

34

Transoceanic infragravity waves impacting Antarctic ice shelves  

Microsoft Academic Search

Long-period oceanic infragravity (IG) waves (ca. [250, 50] s period) are generated along continental coastlines by nonlinear wave interactions of storm-forced shoreward propagating swell. Seismic observations on the Ross Ice Shelf show that free IG waves generated along the Pacific coast of North America propagate transoceanically to Antarctica, where they induce a much higher amplitude shelf response than ocean swell

Peter D. Bromirski; Olga V. Sergienko; Douglas R. MacAyeal

2010-01-01

35

Can We Measure the Wave Function of a SingleWave Packet of Light?  

E-print Network

Can We Measure the Wave Function of a SingleWave Packet of Light? Brownian Motion and Continuous packet of light.- A signal wave packet of light, 1I)&, is correlated to a probe wave packet, 1a Wave Packet Collapse in RepeatedWeak Quantum Nondemolition Measurements ORLY ALTER AND YOSHIHISA

Utah, University of

36

On Dissipation Function of Ocean Waves due to Whitecapping.  

E-print Network

On Dissipation Function of Ocean Waves due to Whitecapping. V.E. Zakharov, A.O. Korotkevich, and A Dissipation Function of Ocean Waves due to White Capping. Scheme of scales kp1 k=2/ pumping inverse cascade Function of Ocean Waves due to White Capping. Why it is important? ­ L.D. Landau ITP RAS ­ Zakharov-70, SCT

Fominov, Yakov

37

The $??$ transition form factor and the pion wave function  

E-print Network

The pion wave function is discussed in the light of the recent CLEO data on the pion gamma transition form factor. It turns out that the wave function is close to the asymptotic form whereas wave functions strongly concentrated in the end-point regions are disfavoured. Consequences for other exclusive quantities, as for instance the pion's electromagnetic form factor, are also discussed.

P. Kroll; M. Raulfs

1996-05-09

38

Parametric Dependence of Ocean Wave-Radar Modulation Transfer Functions  

Microsoft Academic Search

much smaller when the antennas are pointed perpendicular to long waves, however. X band transfer functions measured with horizontally polarized microwave radiation are found to have larger magnitudes than those obtained by using vertical polarization. Under conditions encountered in this experiment, transfer functions are independent of long-wave amplitude when waves and antennas are aligned. Coherence functions, however, depend strongly on

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

1983-01-01

39

Modeling of Wave Impact Using a Pendulum System  

E-print Network

body swinging on a pendulum system is developed. The body on the pendulum goes through a wave free surface driven by gravity at the pendulum's natural frequency. The system's motion and impact force during the entire oscillation time beginning from...

Nie, Chunyong

2011-08-08

40

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

41

A Hammer-Impact, Aluminum, Shear-Wave Seismic Source  

USGS Publications Warehouse

Near-surface seismic surveys often employ hammer impacts to create seismic energy. Shear-wave surveys using horizontally polarized waves require horizontal hammer impacts against a rigid object (the source) that is coupled to the ground surface. I have designed, built, and tested a source made out of aluminum and equipped with spikes to improve coupling. The source is effective in a variety of settings, and it is relatively simple and inexpensive to build.

Haines, Seth S.

2007-01-01

42

Wave energy converters and their impact on power systems  

Microsoft Academic Search

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

43

Statistics of wave functions in mesoscopic systems  

NASA Astrophysics Data System (ADS)

We review the results of a recent study of fluctuations of wave functions in confined chaotic systems. The fluctuations can be due to a random potential or be a consequence of a chaotic scattering by the walls. The entire distribution function of the local amplitudes of the wave functions, f1, and the joint two-point distribution are calculated in various situations. The computation is performed using the supersymmetry technique and employs the studies of a reduced version of the non-linear supersymmetric ?-model developed especially for investigating the properties of a single eigenstate in a discrete spectrum of a chaotic quantum system. For not very large amplitudes, the complete description can be achieved using the zero-dimensional approximation of the ?-model. The distribution function calculated in the limit of various symmetry classes shows the universal behavior known as the Porter-Thomas statistics, and fluctuations at distant points do not correlate. In the crossover regime between the ensembles, the distribution of local amplitudes shows a somewhat more sophisticated behavior: the fluctuations in this case are correlated over distances exceeding the mean free path. For large amplitudes generated by the states the most affected by the localization (we call them prelocalized), the zero-dimensional approximation is no longer valid. Instead, the statistics of their wave functions is determined by nontrivial vacua of the reduced ?-model which is quite similar to the Liouville model known in conformal field theory. In particular, the vacuum state of the reduced ?-model obeys the Liouville equation, which indicates that in two dimensions the prelocalized states have nearly critical properties: we prove their multifractality and power-law statistically averaged envelope |?(r)|2?r-2? at the intermediate range of distances below the localization length with a spectrum of exponents ?<1, as well as obtain a logarithmically-normal tail of the distribution function f1. We also find an evidence of prelocalized states in quasi-one-dimensional wires with the length shorter than the localization length: their statistically averaged envelope has power-law asymptotics, |?(x)|2?x-2, and the tail of the distribution function is similar to that describing localized states in the infinite wires.

Fal'ko, Vladimir I.; Efetov, K. B.

1996-10-01

44

Functional evolution of quantum cylindrical waves  

E-print Network

Kucha{\\v{r}} showed that the quantum dynamics of (1 polarization) cylindrical wave solutions to vacuum general relativity is determined by that of a free axially-symmetric scalar field along arbitrary axially-symmetric foliations of a fixed flat 2+1 dimensional spacetime. We investigate if such a dynamics can be defined {\\em unitarily} within the standard Fock space quantization of the scalar field. Evolution between two arbitrary slices of an arbitrary foliation of the flat spacetime can be built out of a restricted class of evolutions (and their inverses). The restricted evolution is from an initial flat slice to an arbitrary (in general, curved) slice of the flat spacetime and can be decomposed into (i) `time' evolution in which the spatial Minkowskian coordinates serve as spatial coordinates on the initial and the final slice, followed by (ii) the action of a spatial diffeomorphism of the final slice on the data obtained from (i). We show that although the functional evolution of (i) is unitarily implemented in the quantum theory, generic spatial diffeomorphisms of (ii) are not. Our results imply that a Tomanaga-Schwinger type functional evolution of quantum cylindrical waves is not a viable concept even though, remarkably, the more limited notion of functional evolution in Kucha{\\v{r}}'s `half parametrized formalism' is well-defined.

Demian H. J. Cho; Madhavan Varadarajan

2006-10-16

45

Wave functions of log-periodic oscillators  

SciTech Connect

We use the Lewis and Riesenfeld invariant method [J. Math. Phys. 10, 1458 (1969)] and a unitary transformation to obtain the exact Schroedinger wave functions for time-dependent harmonic oscillators exhibiting log-periodic-type behavior. For each oscillator we calculate the quantum fluctuations in the coordinate and momentum as well as the quantum correlations between the coordinate and momentum. We observe that the oscillator with m=m{sub 0}t/t{sub 0} and {omega}={omega}{sub 0}t{sub 0}/t, which exhibits an exact log-periodic oscillation, behaves as the harmonic oscillator with m and {omega} constant.

Bessa, V.; Guedes, I. [Departamento de Fisica, Universidade Federal do Ceara, Campus do Pici, Fortaleza, CE 60455-760 (Brazil)

2011-06-15

46

Wave functions of log-periodic oscillators  

NASA Astrophysics Data System (ADS)

We use the Lewis and Riesenfeld invariant method [J. Math. Phys. 10, 1458 (1969)], 10.1063/1.1664991 and a unitary transformation to obtain the exact Schrödinger wave functions for time-dependent harmonic oscillators exhibiting log-periodic-type behavior. For each oscillator we calculate the quantum fluctuations in the coordinate and momentum as well as the quantum correlations between the coordinate and momentum. We observe that the oscillator with m = m0t/t0 and ? = ?0t0/t, which exhibits an exact log-periodic oscillation, behaves as the harmonic oscillator with m and ? constant.

Bessa, V.; Guedes, I.

2011-06-01

47

Improved wave functions for quantum Monte Carlo  

E-print Network

Improved wave functions for quantum Monte Carlo Priyanka Seth Corpus Christi College, Cambridge Dissertation submitted for the degree of Doctor of Philosophy at the University of Cambridge August 2012 To mum, dad, ìÉìÉ and the memory of êÉ. Preface... been published or is to be published: Chapter 3: P. Seth, P. Lo´pez R?´os and R. J. Needs, “Quantum Monte Carlo study of the first-row atoms and ions”, J. Chem. Phys. 134, 084105 (2011). Chapter 4: P. Lo´pez R´?os, P. Seth, N. D. Drummond and R. J...

Seth, Priyanka

2013-02-05

48

Impact of simulated heat waves on soybean physiology and yield  

Technology Transfer Automated Retrieval System (TEKTRAN)

With increases in mean global temperatures and associated climate change, extreme temperature events are predicted to increase in both intensity and frequency. Despite the clearly documented negative public health impacts of heat waves, the impact on physiology and yields of key agricultural species...

49

Deep Inelastic Scattering and Light-Cone Wave Functions  

E-print Network

In the framework of light-cone QCD sum rules, we study the valence quark distribution function $q(x_B)$ of a pion for moderate $x_B$. The sum rule with the leading twist-2 wave function gives $q(x_B)=\\varphi_\\pi(x_B)$. Twist-4 wave functions give about 30\\% for $x_B\\sim 0.5$. It is shown that QCD sum rule predictions, with the asymptotic pion wave function, are in good agreement with experimental data. We found that a two-hump profile for the twist-2 wave function leads to a valence quark disribution function that contradicts experimental data.

V. M. Belyaev; Mikkel B. Johnson

1996-05-11

50

Analysis of the impacts of Wave Energy Converter arrays on the nearshore wave climate in the Pacific Northwest  

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

51

String wave function across a Kasner singularity  

SciTech Connect

A collision of orbifold planes in 11 dimensions has been proposed as an explanation of the hot big bang. When the two planes are close to each other, the winding membranes become the lightest modes of the theory, and can be effectively described in terms of fundamental strings in a ten-dimensional background. Near the brane collision, the 11-dimensional metric is a Euclidean space times a 1+1-dimensional Milne universe. However, one may expect small perturbations to lead into a more general Kasner background. In this paper we extend the previous classical analysis of winding membranes to Kasner backgrounds, and using the Hamiltonian equations, solve for the wave function of loops with circular symmetry. The evolution across the singularity is regular, and explained in terms of the excitement of higher oscillation modes. We also show there is finite particle production and unitarity is preserved.

Copeland, Edmund J.; Niz, Gustavo [School of Physics and Astronomy, University of Nottingham, University Park, Nottingham NG7 2RD (United Kingdom); Turok, Neil [Perimeter Institute for Theoretical Physics, 31 Caroline Street N, Waterloo, Ontario N2L2Y5 (Canada)

2010-06-15

52

On periodic wave functions of Schrödinger operators on Cayley trees  

E-print Network

In the paper we define periodic wave functions for a (discrete) Schr\\"odinger operator on a Cayley tree. This periodicity depends on a subgroup of a group representation of the Cayley tree. For any subgroup of finite index we give a criterion for eigenvalues of the Schr\\"odinger operator under which there are periodic wave functions. For a normal subgroup of infinite index we describe a class of periodic wave functions.

Fumio Hiroshima; Utkir Rozikov

2013-04-11

53

Heat waves in urban heat islands: interactions, impacts, and mitigation  

NASA Astrophysics Data System (ADS)

Urbanization rates and the intensity of anthropogenic global warming are both on the rise. By the middle of this century, climate change impacts on humans will be largely manifested in urban regions and will result from a combination of global to regional impacts related to greenhouse gas emissions, as well as regional to local impacts related to land-cover changes associated with urbanization. Alarmingly, our understanding of how these two distinct impacts will interact remains very poor. One example, which is the focus of this study, is the interaction of urban heat islands and heat waves. Urban heat islands (UHIs) are spatial anomalies consisting of higher temperatures over built terrain; while their intensity varies with many factors, it consistently increases with city size. UHIs will hence intensify in the future as cities expand. Heat waves are temporal anomalies in the regional temperatures that affect both urban and rural areas; there is high certainty that the frequency and intensity of such waves will increase as a result global warming. However, whether urban and rural temperatures respond in the same way to heat waves remains a critical unanswered question. In this study, a combination of observational and modeling analyses of a heat wave event over the Baltimore-Washington urban corridor reveals synergistic interactions between urban heat islands and heat waves. Not only do heat waves increase the regional temperatures, but they also intensify the difference between urban and rural temperatures. That is, their impact is stronger in cities and the urban heat stress during such waves is larger than the sum of the background urban heat island effect and the heat wave effect. We also develop a simple analytical model of this interaction that suggests that this exacerbated impact in urban areas is primarily to the lack of surface moisture, with low wind speeds also playing a smaller role. Finally, the effectiveness of cool and green roofs as UHI mitigation strategies during intense heat waves are evaluated at city scales. These strategies are shown to reduce urban surface temperatures in the Baltimore-Washington corridor by about 5 K and urban air temperatures by about 1 K. These reductions are most significant in the dense urban cores of the two cities, but they are not sufficient to fully offset the UHI effect.

Bou-Zeid, E.; Li, D.

2013-12-01

54

GREEN'S FUNCTIONS FOR WATER WAVES IN POROUS STRUCTURES  

E-print Network

's functions suitable for water-wave problems involving porous structures are obtained by integrating solutions-dimensional problem, when the sides of the breakwater are vertical and the water depth is constant, it is possible and h is the water depth. In the standard water-wave problem for time-harmonic waves, K = 2 /g where

55

Angular correlation function and scattering coefficient of electromagnetic waves  

E-print Network

Angular correlation function and scattering coefficient of electromagnetic waves scattered We study three-dimensional (3-D) electromagnetic wave scattering from a buried object under a two-3232(98)00412-8] OCIS codes: 290.0290, 290.5880. 1. INTRODUCTION The study of electromagnetic wave scattering

Zhang, Guifu

56

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

57

Pain's Impact on Adaptive Functioning  

ERIC Educational Resources Information Center

Background: Pain interferes with the functioning of typical children, but no study has examined its effect on children with pre-existing intellectual disabilities (ID). Methods: Caregivers of 63 children observed their children for 2-h periods and recorded in 1-week diaries: pain presence, cause, intensity and duration. Caregivers also recorded…

Breau, L. M.; Camfield, C. S.; McGrath, P. J.; Finley, G. A.

2007-01-01

58

Physical measurements of breaking wave impact on a floating wave energy converter  

NASA Astrophysics Data System (ADS)

Marine energy converter must both efficiently extract energy in small to moderate seas and also successfully survive storms and potential collisions. Extreme loads on devices are therefore an important consideration in their design process. X-MED is a SuperGen UKCMER project and is a collaboration between the Universities of Manchester, Edinburgh and Plymouth and the Scottish Association for Marine Sciences. Its objective is to extend the knowledge of extreme loads due to waves, currents, flotsam and mammal impacts. Plymouth Universities contribution to the X-MED project involves measuring the loading and response of a taut moored floating body due to steep and breaking wave impacts, in both long crested and directional sea states. These measurements are then to be reproduced in STAR-CCM+, a commercial volume of fluid CFD solver, so as to develop techniques to predict the wave loading on wave energy converters. The measurements presented here were conducted in Plymouth Universities newly opened COAST laboratories 35m long, 15.5m wide and 3m deep ocean basin. A 0.5m diameter taut moored hemispherical buoy was used to represent a floating wave energy device or support structure. The changes in the buoys 6 degree of freedom motion and mooring loads are presented due to focused breaking wave impacts, with the breaking point of the wave changed relative to the buoy.

Hann, Martyn R.; Greaves, Deborah M.; Raby, Alison

2013-04-01

59

The impact of wave energy farms in the shoreline wave climate: Portuguese pilot zone case study using Pelamis energy wave devices  

Microsoft Academic Search

This paper describes the study of the impact of energy absorption by wave farms on the nearshore wave climate and, in special, the influence of the incident wave conditions and the number and position of the wave farms, on the nearshore wave characteristics is studied and discussed. The study was applied to the maritime zone at the West coast off

Artur Palha; Lourenço Mendes; Conceição Juana Fortes; Ana Brito-Melo; António Sarmento

2010-01-01

60

Has the impact of heat waves on mortality changed in France since the European heat wave of summer 2003? A study of the 2006 heat wave  

E-print Network

Has the impact of heat waves on mortality changed in France since the European heat wave of summer 2003? A study of the 2006 heat wave Fouillet Anne 1 , Rey Gr goireé 1 , Wagner V r neé è 2 , Laaidi wave occurred in Western Europe. Since the2003 heat wave, several preventive measures and an alert

Boyer, Edmond

61

Six Impossible Things: Fractional Charge From Laughlin's Wave Function  

SciTech Connect

The Laughlin's wave function is found to be the zero-energy ground state of a {delta}-function Hamiltonian. The finite negative value of the ground state energy which is 91 per cent of Wigner value, can be obtained only when Coulomb correlations are introduced. The Laughlin's wave function is of short range and it overlaps with that of the exact wave functions of small (number of electrons 2 or 5) systems. (i) It is impossible to obtain fractional charge from Laughlin's wave function. (ii) It is impossible to prove that the Laughlin's wave function gives the ground state of the Coulomb Hamiltonian. (iii) It is impossible to have particle-hole symmetry in the Laughlin's wave function. (iv) It is impossible to derive the value of m in the Laughlin's wave function. The value of m in {psi}{sub m} can not be proved to be 3 or 5. (v) It is impossible to prove that the Laughlin's state is incompressible because the compressible states are also likely. (vi) It is impossible for the Laughlin's wave function to have spin. This effort is directed to explain the experimental data of quantum Hall effect in GaAs/AlGaAs.

Shrivastava, Keshav N. [Department of Physics, Faculty of Science, University of Malaya, Kuala Lumpur 50603 (Malaysia)

2010-12-23

62

Photon wave functions, wave-packet quantization of light, and coherence theory  

E-print Network

The monochromatic Dirac and polychromatic Titulaer-Glauber quantized field theories (QFTs) of electromagnetism are derived from a photon-energy wave function in much the same way that one derives QFT for electrons, that is, by quantization of a single-particle wave function. The photon wave function and its equation of motion are established from the Einstein energy-momentum-mass relation, assuming a local energy density. This yields a theory of photon wave mechanics (PWM). The proper Lorentz-invariant single-photon scalar product is found to be non-local in coordinate space, and is shown to correspond to orthogonalization of the Titulaer-Glauber wave-packet modes. The wave functions of PWM and mode functions of QFT are shown to be equivalent, evolving via identical equations of motion, and completely describe photonic states. We generalize PWM to two or more photons, and show how to switch between the PWM and QFT viewpoints. The second-order coherence tensors of classical coherence theory and the two-photon wave functions are shown to propagate equivalently. We give examples of beam-like states, which can be used as photon wave functions in PWM, or modes in QFT. We propose a practical mode converter based on spectral filtering to convert between wave packets and their corresponding biorthogonal dual wave packets.

Brian J. Smith; M. G. Raymer

2007-12-09

63

Impact-induced tensile waves in a kind of phase-transforming materials  

E-print Network

This paper concerns the global propagation of impact-induced tensile waves in a kind of phase-transforming materials. It is well-known that the governing system of partial differential equations is hyperbolic-elliptic and the initial-boundary value problem is not well-posed at all levels of loading. By making use of fully nonlinear stress-strain curve to model this material, Dai and Kong succeeded in constructing a physical solution of the above initial-boundary value problem. For the impact of intermediate range, they assumed that $\\beta<3\\alpha$ in the stress-response function for simplicity. In this paper, we revisit the impact problem and consider the propagation of impact-induced tensile waves for all values of the parameters $\\alpha$ and $\\beta$. The physical solutions for all levels of loading are obtained completely.

Shou-Jun Huang

2010-07-23

64

Gravity-related wave function collapse: Is superfluid He exceptional?  

E-print Network

The gravity-related model of spontaneous wave function collapse, a longtime hypothesis, damps the massive Schr\\"odinger Cat states in quantum theory. We extend the hypothesis and assume that spontaneous wave function collapses are responsible for the emergence of Newton interaction. Superfluid helium would then show significant and testable gravitational anomalies.

Lajos Diósi

2013-02-21

65

Measurement of Light-Cone Wave Functions by Diffractive Dissociation  

E-print Network

Diffractive dissociation of particles can be used to study their light-cone wave functions. Results from Fermilab experiment E791 for diffractive dissociation of 500 GeV/c pi- mesons into di-jets show that the |q qbar> light-cone asymptotic wave function describes the data well for Q^2 ~ 10 (GeV/c)^2 or more.

Daniel Ashery

2002-05-07

66

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

67

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

68

Underwater Mach wave radiation from impact pile driving: theory and observation.  

PubMed

The underwater noise from impact pile driving is studied using a finite element model for the sound generation and parabolic equation model for propagation. Results are compared with measurements using a vertical line array deployed at a marine construction site in Puget Sound. It is shown that the dominant underwater noise from impact driving is from the Mach wave associated with the radial expansion of the pile that propagates down the pile after impact at supersonic speed. The predictions of vertical arrival angle associated with the Mach cone, peak pressure level as function of depth, and dominant features of the pressure time series compare well with corresponding field observations. PMID:21895063

Reinhall, Per G; Dahl, Peter H

2011-09-01

69

Effect of Forcing Function on Nonlinear Acoustic Standing Waves  

NASA Technical Reports Server (NTRS)

Nonlinear acoustic standing waves of high amplitude have been demonstrated by utilizing the effects of resonator shape to prevent the pressure waves from entering saturation. Experimentally, nonlinear acoustic standing waves have been generated by shaking an entire resonating cavity. While this promotes more efficient energy transfer than a piston-driven resonator, it also introduces complicated structural dynamics into the system. Experiments have shown that these dynamics result in resonator forcing functions comprised of a sum of several Fourier modes. However, previous numerical studies of the acoustics generated within the resonator assumed simple sinusoidal waves as the driving force. Using a previously developed numerical code, this paper demonstrates the effects of using a forcing function constructed with a series of harmonic sinusoidal waves on resonating cavities. From these results, a method will be demonstrated which allows the direct numerical analysis of experimentally generated nonlinear acoustic waves in resonators driven by harmonic forcing functions.

Finkheiner, Joshua R.; Li, Xiao-Fan; Raman, Ganesh; Daniels, Chris; Steinetz, Bruce

2003-01-01

70

Impact of rheumatoid arthritis on sexual function  

PubMed Central

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. PMID:24829873

Tristano, Antonio G

2014-01-01

71

Stringy wave function for an S{sup 3} cosmology  

SciTech Connect

Using the recent observations of the relation between the Hartle-Hawking wave function and the topological string partition function, we propose a wave function for scalar metric fluctuations on S{sup 3} embedded in a Calabi-Yau manifold. This problem maps to a study of noncritical bosonic string propagating on a circle at the self-dual radius. This can be viewed as a stringy toy model for a quantum cosmology.

Gukov, Sergei; Saraikin, Kirill; Vafa, Cumrun [Jefferson Physical Laboratory, Harvard University, Cambridge, Massachusetts 02138 (United States)

2006-03-15

72

Modular matrices from universal wave-function overlaps in Gutzwiller-projected parton wave functions  

NASA Astrophysics Data System (ADS)

We implement the universal wave-function overlap (UWFO) method to extract modular S and T matrices for topological orders in Gutzwiller-projected parton wave functions (GPWFs). The modular S and T matrices generate a projective representation of S L (2 ,Z ) on the degenerate-ground-state Hilbert space on a torus and may fully characterize the 2+1D topological orders, i.e., the quasiparticle statistics and chiral central charge (up to E8 bosonic quantum Hall states). We use the variational Monte Carlo method to computed the S and T matrices of the chiral spin liquid (CSL) constructed by the GPWF on the square lattice, and we confirm that the CSL carries the same topological order as the ? =1/2 bosonic Laughlin state. We find that the nonuniversal exponents in the UWFO can be small, and direct numerical computation can be applied on relatively large systems. The UWFO may be a powerful method to calculate the topological order in GPWFs.

Mei, Jia-Wei; Wen, Xiao-Gang

2015-03-01

73

Nonstandard jump functions for radially symmetric shock waves  

SciTech Connect

Nonstandard analysis is applied to derive generalized jump functions for radially symmetric, one-dimensional, magnetogasdynamic shock waves. It is assumed that the shock wave jumps occur on infinitesimal intervals, and the jump functions for the physical parameters occur smoothly across these intervals. Locally integrable predistributions of the Heaviside function are used to model the flow variables across a shock wave. The equations of motion expressed in nonconservative form are then applied to derive unambiguous relationships between the jump functions for the physical parameters for two families of self-similar flows. It is shown that the microstructures for these families of radially symmetric, magnetogasdynamic shock waves coincide in a nonstandard sense for a specified density jump function

Baty, Roy S.; Tucker, Don H.; Stanescu, Dan

2008-10-01

74

Proton Wave Functions in a Uniform Magnetic Field  

SciTech Connect

The wave function of the d-quark in the ground state of the proton, and how it is affected in the presence of a uniform background magnetic field is calculated in lattice QCD. We focus on the wave functions in the Landau and Coulomb gauges. When the quarks are annihilated at different lattice sites, we observe the formation of a scalar u-d diquark pair within the proton in the Landau gauge, which is not present in the Coulomb gauge. The overall distortion of the wave function under a very large magnetic field, as demanded by the quantisation conditions on the field, is quite small.

Roberts, Dale S.; Kamleh, Waseem; Leinweber, Derek B. [Special Research Centre for the Subatomic Structure of Matter and Department of Physics, University of Adelaide 5005 (Australia); Bowman, Patrick O. [Centre for Theoretical Chemistry and Physics and Institute of Natural Sciences, Massey University (Albany), Private Bag 102904, North Shore City 0745 (New Zealand)

2011-05-24

75

Wave function of string and membrane and spacetime geometry  

E-print Network

A first-quantized string (and membrane) theory is developed here by using a general wave function of the string (and membrane), analogously to the first-quantized quantum theory of a point particle. From the general wave function of the string (and membrane), the properties of the string (and membrane) such as its relation to Bosons, Fermions and spacetime are investigated. The string and membrane wave functions are found to be very useful and we can deduce Klein-Gordon equation, Dirac equation and the fundamental property of the spacetime from this new starting point.

Hongwei Xiong; Shujuan Liu

2002-11-18

76

Wave functions of elliptical quantum dots in a magnetic field  

NASA Astrophysics Data System (ADS)

We use the variational principle to obtain the wave functions of elliptical quantum dots under the influence of an external magnetic field. For the first excited states, whose wave functions have recently been mapped experimentally, we find a simple expression, based on a linear combination of the wave functions in the absence of a magnetic field. The results illustrate how a magnetic field breaks the x-y symmetry and mixes the corresponding eigenstates. The obtained eigenenergies agree well with those obtained by more involved analytical and numerical methods.

Zhou, Daming; Lorke, Axel

2015-03-01

77

Measurement of Light-Cone Wave Functions by Diffractive Dissociation  

E-print Network

Diffractive dissociation of particles can be used to study their light-cone wave function. Results from Fermilab experiment E791 for diffractive dissociation of 500 GeV/c $\\pi^-$ mesons into di-jets are presented. The results show that the $|q\\bar {q}>$ light-cone asymptotic wave function describes the data well for $Q^2 \\sim 10 ~{\\rm (GeV/c)^2}$ or more. Evidence for color transparency comes from a measurement of the $A$-dependence of the yield of the diffractive di-jets. It is proposed to carry out similar studies for the light-cone wave function of the photon.

Daniel Ashery

2000-08-22

78

Wave function statistics and multifractality in disordered systems  

E-print Network

Wave function statistics and multifractality in disordered systems Alexander D. Mirlin Forschungszentrum Karlsruhe & Universit¨at Karlsruhe http://www-tkm.physik.uni-karlsruhe.de/mirlin/ Workshop-r ) disorder - ensemble - statistical treatment: mesoscopic fluctuations Classical analogue: Electromagnetic

Fominov, Yakov

79

Schmidt decomposition for non-collinear biphoton angular wave functions  

E-print Network

Schmidt modes of non-collinear biphoton angular wave functions are found analytically. The experimentally realizable procedure is described for their separation. Parameters of the Schmidt decomposition are used for evaluation of the degree of biphoton's angular entanglement.

Mikhail Fedorov

2014-11-08

80

The Wave Function with Maximal Backo w  

Microsoft Academic Search

For a 1D free wave packet, with its momentum distribution being localized on the positive half line, position probability may move to the left during some intermediate stage of its time evolution. Bracken and Melloy have observed that the maximal amount, by which the left half space position probability can increase, is a dimensionless number. This number is independent from

M. Penz; G. Gr; P. Wagner

81

Multi-time wave functions for quantum field theory  

SciTech Connect

Multi-time wave functions such as ?(t{sub 1},x{sub 1},…,t{sub N},x{sub N}) have one time variable t{sub j} for each particle. This type of wave function arises as a relativistic generalization of the wave function ?(t,x{sub 1},…,x{sub N}) 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. -- Highlights: •Multi-time wave functions are manifestly Lorentz-covariant objects. •We develop consistent multi-time equations with interaction for quantum field theory. •We discuss in detail a particular model with particle creation and annihilation. •We show how multi-time wave functions are related to the Tomonaga–Schwinger approach. •We show that they have a simple representation in terms of operator valued fields.

Petrat, Sören, E-mail: petrat@math.lmu.de [Mathematisches Institut, Ludwig-Maximilians-Universität, Theresienstr. 39, 80333 München (Germany); Tumulka, Roderich, E-mail: tumulka@math.rutgers.edu [Department of Mathematics, Rutgers University, 110 Frelinghuysen Road, Piscataway, NJ 08854-8019 (United States)

2014-06-15

82

Study of Two-Nucleon Wave Functions in 3He  

NASA Astrophysics Data System (ADS)

The reaction 3He(p, 2p)pn has been studied at 250 and 400 MeV in a quasifree scattering arrangement characterized by P-->(recoil)=0 and various excitation or total energies E(recoil) of the unobserved p-n pair. The 3He spectral function deduced in the framework of the plane-wave impulse approximation is compared to the predictions of Faddeev and variational calculations. Comparisons are also made with p-n relative-motion momentum distributions calculated as the overlap between plane waves for the p-n pair and Irving, Irving-Gunn, and Khanna wave functions for 3He.

Bracco, A.; Gubler, H. P.; Hasell, D. K.; van Oers, W. T. H.; Epstein, M. B.; Margaziotis, D. J.; Abegg, R.; Miller, C. A.; Postma, H.; Stetz, A. W.; Schwandt, P.

1983-05-01

83

Impact loads and wave kinematics on a fixed truncated circular cylinder due to nonlinear waves in a 2-D tank  

E-print Network

This thesis presents a result of measurements and analyses of the wave kinematics and impact loads on a scaled ISSC-TLP column fixed in a 2-D wave tank. The objective is to find out the mechanics of impact loads varied with kinematics in both space...

Zou, Jun

1995-01-01

84

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

PubMed

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

85

Ultrarelativistic quasiclassical wave functions in strong laser and atomic fields  

NASA Astrophysics Data System (ADS)

The problem of an ultrarelativistic charge in the presence of an atomic and a plane-wave field is investigated in the quasiclassical regime by including exactly the effects of both fields. Starting from the quasiclassical Green's function obtained by Di Piazza and Milstein [Phys. Lett. B 717, 224 (2012), 10.1016/j.physletb.2012.09.043], the corresponding in- and out-wave functions are derived in the experimentally relevant case of the plane wave counterpropagating with respect to the initial momentum of the particle. The knowledge of these electron wave functions opens the possibility of investigating a variety of problems in strong-field QED, where both the atomic field and the laser field are strong enough to be taken into account exactly from the beginning in the calculations.

Di Piazza, A.; Milstein, A. I.

2014-06-01

86

Matter Density and Relativistic Models of Wave Function Collapse  

NASA Astrophysics Data System (ADS)

Mathematical models for the stochastic evolution of wave functions that combine the unitary evolution according to the Schrödinger equation and the collapse postulate of quantum theory are well understood for non-relativistic quantum mechanics. Recently, there has been progress in making these models relativistic. But even with a fully relativistic law for the wave function evolution, a problem with relativity remains: Different Lorentz frames may yield conflicting values for the matter density at a space-time point. We propose here a relativistic law for the matter density function. According to our proposal, the matter density function at a space-time point x is obtained from the wave function ? on the past light cone of x by setting the i-th particle position in |?|2 equal to x, integrating over the other particle positions, and averaging over i. We show that the predictions that follow from this proposal agree with all known experimental facts.

Bedingham, Daniel; Dürr, Detlef; Ghirardi, GianCarlo; Goldstein, Sheldon; Tumulka, Roderich; Zanghì, Nino

2013-08-01

87

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

88

Rapidity resummation for B-meson wave functions  

NASA Astrophysics Data System (ADS)

Transverse-momentum dependent (TMD) hadronic wave functions develop light-cone divergences under QCD corrections, which are commonly regularized by the rapidity ? of gauge vector defining the non-light-like Wilson lines. The yielding rapidity logarithms from infrared enhancement need to be resummed for both hadronic wave functions and short-distance functions, to achieve scheme-independent calculations of physical quantities. We briefly review the recent progress on the rapidity resummation for B-meson wave functions which are the key ingredients of TMD factorization formulae for radiative-leptonic, semi-leptonic and non-leptonic B-meson decays. The crucial observation is that rapidity resummation induces a strong suppression of B-meson wave functions at small light-quark momentum, strengthening the applicability of TMD factorization in exclusive B-meson decays. The phenomenological consequence of rapidity-resummation improved B-meson wave functions is further discussed in the context of B ? ? transition form factors at large hadronic recoil.

Shen, Yue-Long; Wang, Yu-Ming

2014-11-01

89

Rapidity resummation for $B$-meson wave functions  

E-print Network

Transverse-momentum dependent (TMD) hadronic wave functions develop light-cone divergences under QCD corrections, which are commonly regularized by the rapidity $\\zeta$ of gauge vector defining the non-light-like Wilson lines. The yielding rapidity logarithms from infrared enhancement need to be resummed for both hadronic wave functions and short-distance functions, to achieve scheme-independent calculations of physical quantities. We briefly review the recent progress on the rapidity resummation for $B$-meson wave functions which are the key ingredients of TMD factorization formulae for radiative-leptonic, semi-leptonic and non-leptonic $B$-meson decays. The crucial observation is that rapidity resummation induces a strong suppression of $B$-meson wave functions at small light-quark momentum, strengthening the applicability of TMD factorization in exclusive $B$-meson decays. The phenomenological consequence of rapidity-resummation improved $B$-meson wave functions is further discussed in the context of $B \\to \\pi$ transition form factors at large hadronic recoil.

Yue-Long Shen; Yu-Ming Wang

2014-09-03

90

Projections of heat waves with high impact on human health in Europe  

E-print Network

Projections of heat waves with high impact on human health in Europe A. Amengual1, V. Homar1, R will result in more intense, more frequent and longer lasting heat waves. The most hazardous conditions emerge and light winds for several consecutive days. Here, we assess present and future heat wave impacts on human

Romero, Romu

91

Joint Resummation for TMD Wave Function of Pion  

NASA Astrophysics Data System (ADS)

QCD corrections to transverse-momentum-dependent pion wave function develop the mixed double logarithm ln x ln(? P2/k_T^2), when the gluon emission is collinear to the energetic pion. The fist scheme-independent kT factorization formula for ?*? ? ? transition form factor is achieved by resumming all the enhanced logarithms for both pion wave function and short-distance coefficient function. High-order QCD corrections and transfer momentum ? {Q2} dependence of pion form factor are found to be distinct from those predicted by the conventional resummation approach.

Wang, Yu-Ming

2015-02-01

92

Love wave propagation in functionally graded piezoelectric material layer  

Microsoft Academic Search

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

Jianke Du; Xiaoying Jin; Ji Wang; Kai Xian

2007-01-01

93

The Light-Cone Wave Function of the Pion  

E-print Network

The light-cone wave function of the pion is calculated within the Nambu-Jona-Lasinio model. The result is used to derive the pion electromagnetic form factor, charge radius, structure function, pi-gamma transition form factor and distribution amplitude.

T. Heinzl

2000-08-30

94

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

95

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

96

Transverse instability of a plane front of fast impact ionization waves  

NASA Astrophysics Data System (ADS)

The transverse instability of a plane front of fast impact ionization waves in p +- n- n + semiconductor structures with a finite concentration of donors N in the n layer has been theoretically analyzed. It is assumed that the high velocity u of impact ionization waves is ensured owing to the avalanche multiplication of the uniform background of electrons and holes whose concentration ?b ahead of the front is high enough for the continuum approximation to be applicable. The problem of the calculation of the growth rate s of a small harmonic perturbation with wavenumber k is reduced to the eigenvalue problem for a specific homogeneous Volterra equation of the second kind containing the sum of double and triple integrals of an unknown eigenfunction. This problem has been solved by the method of successive approximations. It has been shown that the function s( k) for small k values increases monotonically in agreement with the analytical theory reported in Thermal Engineering 58 (13), 1119 (2011), reaches a maximum s M at k = k M, then decreases, and becomes negative at k > k 01. This behavior of the function s( k) for short-wavelength perturbations is due to a decrease in the distortion of the field owing to a finite thickness of the space charge region of the front and "smearing" of perturbation of concentrations owing to the transverse transport of charge carriers. The similarity laws for perturbations with k ? k M have been established: at fixed ?b values and the maximum field strength on the front E 0M, the growth rate s depends only on the ratio k/N and the boundary wavenumber k 01 ? N. The parameters s M, k M, and k 01, which determine the perturbation growth dynamics and the upper boundary of the instability region for impact ionization waves, have been presented as functions of E 0M. These dependences indicate that the model of a plane impact ionization wave is insufficient for describing the operation of avalanche voltage sharpers and that fronts of fast streamers in the continuum approximation should be stable with respect to transverse perturbations in agreement with the previously reported numerical simulation results. The results have been confirmed by the numerical simulation of the evolution of small harmonic perturbations of the steady-state plane impact ionization wave.

Kyuregyan, A. S.

2012-05-01

97

Reconstructing the Shock Wave From the Wolfe Creek Meteorite Impact.  

NASA Astrophysics Data System (ADS)

The Wolfe Creek meteorite crater is an 800m diameter impact structure located in the Tanami Desert near Hall's Creek, Western Australia. The crater formed <300000 years ago, and is the 2nd largest crater from which fragments of the impacting meteorite (a medium octahedrite) have been recovered. We present the results of new ground based geophysical (magnetics and gravity) surveys conducted over the structure in July-August, 2003. The results highlight the simple structure of the crater under the infilling sediments, and track the extent of deformation and the ejecta blanket under the encroaching sanddunes. The variations in the dip of the foliations around the crater rim confirm that the crater approached from East-Northeast, as deduced from the ejecta distribution, and provide constraints on the kinetic energy and angle of the impactor. We also use the distribution of shocked quartz in the target rock (Devonian sandstones) to reconstruct the shock loading conditions of the impact using the Grieve and Robertson (1976) criterion. We also use a Simplified Arbitrary Langrangian-Eulerian hydrocode (SALE 2) to simulate the propagation of shock waves through a material described by a Tillotson equation of state. Using the deformational and PT constraints of the Wolfe-Creek crater, we can estimate the partitioning of kinetic energy as a result of this medium-size impact.

Heine, C.; O'Neill, C. J.

2003-12-01

98

Monitoring the wave function by time continuous position measurement  

E-print Network

We consider a single copy of a quantum particle moving in a potential and show that it is possible to monitor its complete wave function by only continuously measuring its position. While we assume that the potential is known, no information is available about its state initially. In order to monitor the wave function, an estimate of the wave function is propagated due to the influence of the potential and continuously updated according to the results of the position measurement. We demonstrate by numerical simulations that the estimation reaches arbitrary values of accuracy below 100 percent within a finite time period for the potentials we study. In this way our method grants, a certain time after the beginning of the measurement, an accurate real-time record of the state evolution including the influence of the continuous measurement. Moreover, it is robust against sudden perturbations of the system as for example random momentum kicks from environmental particles, provided they occur not too frequently.

Konrad, Thomas; Petruccione, Francesco; Diósi, Lajos

2009-01-01

99

Monitoring the wave function by time continuous position measurement  

E-print Network

We consider a single copy of a quantum particle moving in a potential and show that it is possible to monitor its complete wave function by only continuously measuring its position. While we assume that the potential is known, no information is available about its state initially. In order to monitor the wave function, an estimate of the wave function is propagated due to the influence of the potential and continuously updated according to the results of the position measurement. We demonstrate by numerical simulations that the estimation reaches arbitrary values of accuracy below 100 percent within a finite time period for the potentials we study. In this way our method grants, a certain time after the beginning of the measurement, an accurate real-time record of the state evolution including the influence of the continuous measurement. Moreover, it is robust against sudden perturbations of the system as for example random momentum kicks from environmental particles, provided they occur not too frequently.

Thomas Konrad; Andreas Rothe; Francesco Petruccione; Lajos Diósi

2009-02-13

100

Laws of Nature and the Reality of the Wave Function  

E-print Network

In this paper I review three different positions on the wave function, namely: nomological realism, dispositionalism, and configuration space realism by regarding as essential their capacity to account for the world of our experience. I conclude that the first two positions are committed to regard the wave function as an abstract entity. The third position will be shown to be a merely speculative attempt to derive a primitive ontology from a reified mathematical space. Without entering any discussion about nominalism, I conclude that an elimination of abstract entities from one's ontology commits one to instrumentalism about the wave function, a position that therefore is not as unmotivated as it has seemed to be to many philosophers.

Dorato, Mauro

2015-01-01

101

Counting Rule for Hadronic Light-Cone Wave Functions  

E-print Network

We introduce a systematic way to write down the Fock components of a hadronic light-cone wave function with $n$ partons and orbital angular momentum projection $l_z$. We show that the wave function amplitude $\\psi_n(x_i,k_{i\\perp},l_{zi})$ has a leading behavior $1/(k^2_\\perp)^{[n+|l_z|+{\\rm min}(n'+|l_z'|)]/2-1}$ when all parton transverse momenta are uniformly large, where $n'$ and $l_z'$ are the number of partons and orbital angular momentum projection, respectively, of an amplitude that mixes under renormalization. The result can be used as a constraint in modeling the hadronic light-cone wave functions. We also derive a generalized counting rule for hard exclusive processes involving parton orbital angular momentum and hadron helicity flip.

Xiangdong Ji; Jian-Ping Ma; Feng Yuan

2003-01-17

102

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

103

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 H.

2007-01-01

104

Hadronic Spectra and Light-Front Wave Functions in Holographic QCD  

Microsoft Academic Search

We show how the string amplitude Ï(z) defined on the fifth dimension in AdSâ space can be precisely mapped to the light-front wave functions of hadrons in physical space-time. We find an exact correspondence between the holographic variable z and an impact variable ζ, which represents the measure of transverse separation of the constituents within the hadrons. In addition, we

Stanley J. Brodsky; Guy F. de Teramond

2006-01-01

105

Concerning Infeasibility of the Wave Functions of the Universe  

NASA Astrophysics Data System (ADS)

Difficulties with finding the general exact solutions to the Wheeler-DeWitt equation, i.e. the wave functions of the Universe, are known and well documented. However, the present paper draws attention to a completely different matter, which is rarely if ever discussed in relation to this equation, namely, the time complexity of the Wheeler-DeWitt equation, that is, the time required to exactly solve the equation for a given universe. As it is shown in the paper, whatever generic exact algorithm is used to solve the equation, most likely such an algorithm cannot be faster than brute force, which makes the wave functions of the Universe infeasible.

Bolotin, Arkady

2015-02-01

106

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

107

Compressive Direct Measurement of the Quantum Wave Function  

NASA Astrophysics Data System (ADS)

The direct measurement of a complex wave function has been recently realized by using weak values. In this Letter, we introduce a method that exploits sparsity for the compressive measurement of the transverse spatial wave function of photons. The procedure involves weak measurements of random projection operators in the spatial domain followed by postselection in the momentum basis. Using this method, we experimentally measure a 192-dimensional state with a fidelity of 90% using only 25 percent of the total required measurements. Furthermore, we demonstrate the measurement of a 19 200-dimensional state, a task that would require an unfeasibly large acquiring time with the standard direct measurement technique.

Mirhosseini, Mohammad; Magaña-Loaiza, Omar S.; Hashemi Rafsanjani, Seyed Mohammad; Boyd, Robert W.

2014-08-01

108

Concerning Infeasibility of the Wave Functions of the Universe  

E-print Network

Difficulties with finding the general exact solutions to the Wheeler-DeWitt equation, i.e. the wave functions of the Universe, are known and well documented. However, the present paper draws attention to a completely different matter, which is rarely if ever discussed in relation to this equation, namely, the time complexity of the Wheeler-DeWitt equation, that is, the time required to exactly solve the equation for a given universe. As it is shown in the paper, whatever generic exact algorithm is used to solve the equation, most likely such an algorithm cannot be faster than brute force, which makes the wave functions of the Universe infeasible.

Arkady Bolotin

2015-02-04

109

Optimal multiconfiguration approximation of an N-fermion wave function  

NASA Astrophysics Data System (ADS)

We propose a simple iterative algorithm to construct the optimal multiconfiguration approximation of an N-fermion wave function. Namely, M ?N single-particle orbitals are sought iteratively so that the projection of the given wave function in the CMN-dimensional configuration subspace is maximized. The algorithm has a monotonic convergence property and can be easily parallelized. The significance of the algorithm on the study of geometric entanglement in a multifermion system and its implication on the multiconfiguration time-dependent Hartree-Fock (MCTDHF) are discussed. The ground state and real-time dynamics of spinless fermions with nearest-neighbor interaction are studied using this algorithm, discussing several subtleties.

Zhang, J. M.; Kollar, Marcus

2014-01-01

110

Quantum-mechanical modeling without wave functions  

NASA Astrophysics Data System (ADS)

It has been shown that the variational principle can be used as the practical way to find the electron density and the total energy in terms of the density functional theory without solving the Kohn-Sham equations (the so-called orbital-free approach). The equilibrium interatomic distances and binding energies found using examples of diatomic systems Si2, Al2, and P2 are in good agreement with the published data. The results obtained for Si-Al, Si-P, and Al-P dimers are also close to the results obtained by the Kohn-Sham method.

Zavodinsky, V. G.; Gorkusha, O. A.

2014-11-01

111

Impact of autocorrelation on functional connectivity.  

PubMed

Although the impact of serial correlation (autocorrelation) in residuals of general linear models for fMRI time-series has been studied extensively, the effect of autocorrelation on functional connectivity studies has been largely neglected until recently. Some recent studies based on results from economics have questioned the conventional estimation of functional connectivity and argue that not correcting for autocorrelation in fMRI time-series results in "spurious" correlation coefficients. In this paper, first we assess the effect of autocorrelation on Pearson correlation coefficient through theoretical approximation and simulation. Then we present this effect on real fMRI data. To our knowledge this is the first work comprehensively investigating the effect of autocorrelation on functional connectivity estimates. Our results show that although FC values are altered, even following correction for autocorrelation, results of hypothesis testing on FC values remain very similar to those before correction. In real data we show this is true for main effects and also for group difference testing between healthy controls and schizophrenia patients. We further discuss model order selection in the context of autoregressive processes, effects of frequency filtering and propose a preprocessing pipeline for connectivity studies. PMID:25072392

Arbabshirani, Mohammad R; Damaraju, Eswar; Phlypo, Ronald; Plis, Sergey; Allen, Elena; Ma, Sai; Mathalon, Daniel; Preda, Adrian; Vaidya, Jatin G; Adali, Tülay; Calhoun, Vince D

2014-11-15

112

BPS Microstates and the Open Topological String Wave Function  

E-print Network

It has recently been conjectured that the closed topological string wave function computes a grand canonical partition function of BPS black hole states in 4 dimensions: Z_BH=|psi_top|^2. We conjecture that the open topological string wave function also computes a grand canonical partition function, which sums over black holes bound to BPS excitations on D-branes wrapping cycles of the internal Calabi-Yau: Z^open_BPS=|psi^open_top|^2. This conjecture is verified in the case of Type IIA on a local Calabi-Yau threefold involving a Riemann surface, where the degeneracies of BPS states can be computed in q-deformed 2-dimensional Yang-Mills theory.

Mina Aganagic; Andrew Neitzke; Cumrun Vafa

2005-04-06

113

Oblique propagation, wave particle interaction and particle distribution function  

NASA Astrophysics Data System (ADS)

Recent results from the Cluster mission have stimulated theoretical investigations and simulations to explain ion distribution functions observed in the quasi-perp bow shock. High-time resolution observations have revealed distributions of gyrating ions that are gyrophase-bunched. When not produced at the shock, such distributions are believed to be resulting from interactions between field-aligned beams and low frequency beamdriven waves . The Conventional models used to account for such distributions assume that the waves are purely transverse, and that they propagate parallel to the ambient magnetic eld. However observations indicate that these waves are propagating obliquely with respect to the ambient magnetic eld [Meziane et al., 2001]. A theoretical investigation of the non-relativistic wave-particle interaction in a background magnetic eld with the electromagnetic wave propagating obliquely has been addressed previously, resulting in a dynamical system describing the wave interaction with a single ion in the absence of dissipation mechanisms. [Hamza et al., 2005] This dynamical system has been numerically integrated to construct the ion distribution functions by seeding the particles with di erent initial conditions. We compute the particle orbits and simulate the time evolution of the distribution functions based on Liouville's theorem of phase space density conservation. It will be shown that the trapping which is due to the oblique propagation of the wave, gives an explanation for gyrophase-bunching and unstable distributions in velocity space which could trigger instabilities such as firehose and mirror. Therefore this exercise provide insights on the particle dynamics and onset of waves away from the shock. Meziane, K., C. Mazelle, R.P. Lin, D. LeQueau, D.E. Larson, G.K. Parks, R.P. Lepping (2001), Three dimensional observations of gyrating ions distributions far upstream from the Earth's bow shock and their association with low-frequency waves, J. Geophys. Res. 106, 5731 Hamza, A. M., K. Meziane, and C. Mazelle (2006), Oblique propagation and nonlinear wave particle processes, J. Geophys. Res., 111, A04104

Osmane, Adnane; Hamza, A. M.; Meziane, Karim

114

Impact of improved wave dissipation parameterisations on wave-current interactions in a coupled wave-ocean model  

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

115

Parallel eigensolvers in plane-wave Density Functional Theory  

NASA Astrophysics Data System (ADS)

We consider the problem of parallelizing electronic structure computations in plane-wave Density Functional Theory. Because of the limited scalability of Fourier transforms, parallelism has to be found at the eigensolver level. We show how a recently proposed algorithm based on Chebyshev polynomials can scale into the tens of thousands of processors, outperforming block conjugate gradient algorithms for large computations.

Levitt, Antoine; Torrent, Marc

2015-02-01

116

The Born Oppenheimer wave function near level crossing  

E-print Network

The Born Oppenheimer wave function near level crossing J. E. Avron and A. Gordon Department of Physics, Technion, 32000 Haifa, Israel June 19, 2000 Abstract The standard Born Oppenheimer theory does mass ratio. 1 Introduction In 1927, in a landmark paper, Born and Oppenheimer [2] paved the way

117

Interpretation of the wave function of the universe  

SciTech Connect

Hawking and Hartle interpreted their wave function of the universe as giving the probability for the universe to appear from nothing. However, this is not a correct interpretation, since the normalization presupposes a universe, not nothing. Transition probabilities require a measure on the initial state and a physical result requires a physical initial state.

Drees, W.B.

1987-10-01

118

On the Ground State Wave Function of Matrix Theory  

E-print Network

We propose an explicit construction of the leading terms in the asymptotic expansion of the ground state wave function of BFSS SU(N) matrix quantum mechanics. Our proposal is consistent with the expected factorization property in various limits of the Coulomb branch, and involves a different scaling behavior from previous suggestions. We comment on some possible physical implications.

Ying-Hsuan Lin; Xi Yin

2014-02-01

119

Topological wave functions and heat equations  

E-print Network

It is generally known that the holomorphic anomaly equations in topological string theory reflect the quantum mechanical nature of the topological string partition function. We present two new results which make this assertion more precise: (i) we give a new, purely holomorphic version of the holomorphic anomaly equations, clarifying their relation to the heat equation satisfied by the Jacobi theta series; (ii) in cases where the moduli space is a Hermitian symmetric tube domain $G/K$, we show that the general solution of the anomaly equations is a matrix element $\\IP{\\Psi | g | \\Omega}$ of the Schr\\"odinger-Weil representation of a Heisenberg extension of $G$, between an arbitrary state $\\bra{\\Psi}$ and a particular vacuum state $\\ket{\\Omega}$. Based on these results, we speculate on the existence of a one-parameter generalization of the usual topological amplitude, which in symmetric cases transforms in the smallest unitary representation of the duality group $G'$ in three dimensions, and on its relations to hypermultiplet couplings, nonabelian Donaldson-Thomas theory and black hole degeneracies.

Murat Gunaydin; Andrew Neitzke; Boris Pioline

2008-01-10

120

Transverse Momentum Dependent Light-Cone Wave Function of B-Meson and Relation to the Momentum Integrated One  

E-print Network

A direct generalization of the transverse momentum integrated(TMI) light-cone wave function to define a transverse momentum dependent(TMD) light-cone wave function will cause light-cone singularities and they spoil TMD factorization. We motivate a definition in which the light-cone singularities are regularized with non-light like Wilson lines. The defined TMD light-cone wave function has some interesting relations to the corresponding TMI one. When the transverse momentum is very large, the TMD light-cone wave function is determined perturbatively in term of the TMI one. In the impact $b$-space with a small $b$, the TMD light-cone wave function can be factorized in terms of the TMI one. In this letter we study these relations. By-products of our study are the renormalization evolution of the TMI light-cone wave function and the Collins-Soper equation of the TMD light-cone wave function, the later will be useful for resumming Sudakov logarithms.

J. P. Ma; Q. Wang

2005-03-14

121

Modelling of tsunami wave run-up, breaking and impact on vertical wall by SPH method  

NASA Astrophysics Data System (ADS)

Accurate predictions of wave run-up and run-down are important for coastal impact assessment of relatively long waves such as tsunami or storm waves. Wave run-up is, however, a complex process involving nonlinear build-up of the wave front, intensive wave breaking and strong turbulent flow, making the numerical approximation challenging. Recent advanced modeling methodologies could help to overcome these numerical challenges. For a demonstration, we study run-up of non-breaking and breaking solitary waves on vertical wall using two methods, the enhanced Smoothed Particle Hydrodynamics (SPH) method and the traditional non-breaking nonlinear model Tunami-N2. The Tunami-N2 model fails to capture the evolution of steep waves at the proximity of breaking that observed in the experiments. Whereas, the SPH method successfully simulate the wave propagation, breaking, impact on structure and the reform and breaking processes of wave run-down. The study also indicates that inadequate approximation of the wave breaking could lead to significant under-predictions of wave height and impact pressure on structures. The SPH model shows potential applications for accurate impact assessments of wave run-up onto coastal structures.

Dao, M. H.; Xu, H.; Chan, E. S.; Tkalich, P.

2013-06-01

122

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

123

Crustal structure of North Dakota from joint inversion of surface wave dispersion and teleseismic P-wave reciever functions  

NASA Astrophysics Data System (ADS)

Studying and determining crustal structure of the Earth is important for understanding the interior of the Earth. Using methods like receiver functions and surface wave dispersion allows the determination of differences in structure and composition through the crust. Jointly inverting receiver functions and surface wave dispersion reduces the error and over-interpretation of the crustal structure estimation. Receiver functions and surface wave dispersion invert well together because receiver functions are very sensitive to velocity contrasts and vertical travel times, and surface wave dispersion is sensitive to average velocity and insensitive to sharp velocity contrasts. By jointly inverting receiver functions and surface wave dispersion, shear wave velocity profiles can be created to determine the properties of the crustal structure and velocity contrasts. With the use of IRIS Transportable Array stations data throughout the United States, this thesis takes a closer look at the crustal structure of North Dakota through the joint inversion of surface wave dispersion and teleseismic P-wave receiver functions. The receiver functions in North Dakota show shallow sediment effects that affect the joint inversion process. In western North Dakota the Williston basin and in eastern North Dakota the Red River Valley cause ringing effects in the receiver functions. The shallow sediments in North Dakota control and overpower the rest of the crustal signal in the receiver functions, and thus affect the ability of determining the crustal shear wave velocity structure of North Dakota through the joint inversion of receiver functions and surface wave dispersion, thus the use of background geology is necessary.

Walsh, Braden Michael

124

Local properties of three-body atomic wave functions  

SciTech Connect

The local properties and accuracy of the positronium negative-ion (Ps{sup -}) ground-state wave functions obtained by the stochastic variational method (SVM) and by direct solution of the Schroedinger equation with the help of the correlation-function hyperspherical-harmonic method (CFHHM) are studied and compared. Though the energy, calculated by both methods, agrees to up to ten digits, the amplitudes of the values of the operator D=H{psi}/E{psi}-1, characterizing local deviation of the wave function from its true value, in all of the coordinate space in the SVM are consistently larger (by up to five orders of magnitude) than in the CFHHM, despite the fact that the SVM observables except <{delta}(r{sub k})> converge to significantly more digits than the CFHHM observables for their respective selected bases. (c) 2000 The American Physical Society.

Krivec, R. [Department of Theoretical Physics, J. Stefan Institute, P.O. Box 3000, 1001 Ljubljana, (Slovenia)] [Department of Theoretical Physics, J. Stefan Institute, P.O. Box 3000, 1001 Ljubljana, (Slovenia); Mandelzweig, V. B. [Racah Institute of Physics, Hebrew University, Jerusalem 91904, (Israel)] [Racah Institute of Physics, Hebrew University, Jerusalem 91904, (Israel); Varga, K. [Physics Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439 (United States)] [Physics Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439 (United States)

2000-06-01

125

Wave distribution functions estimation of VLF electromagnetic waves observed onboard Geos 1  

Microsoft Academic Search

Two methods to determine the electromagnetic wave distribution function are presented. The first is based on the use of the Dirichlet kernels and provides a local average. It has the disadvantage, however, of a nonsystematic approach to positive solutions. The second uses the maximum entropy concept. It leads to particular solutions that are smooth and positive everywhere. The two methods

F. Lefeuvre; M. Parrot; C. Delannoy

1981-01-01

126

Numerical modeling of wave propagation in functionally graded materials using time-domain spectral Chebyshev elements  

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

127

Elastic response of floating glacier ice to impact of longperiod ocean waves  

E-print Network

Elastic response of floating glacier ice to impact of longperiod ocean waves O. V. Sergienko1 given rise to the question of whether mechanical coupling with waves in the ocean may provide general question: how ocean waves affect the stress regime of floating ice, and in particular, how ocean

Rodgers, Keith

128

Transoceanic infragravity waves impacting Antarctic ice shelves Peter D. Bromirski,1  

E-print Network

that IG- wave forcing may produce ice-shelf fractures that enable abrupt disintegration of ice shelves-forced shoreward propagating swell. Seismic observations on the Ross Ice Shelf show that free IG waves generated ocean swell, IG waves are not significantly damped by sea ice, and thus impact the ice shelf throughout

Boyce, C. Kevin

129

Impact wave deposits provide new constraints on the location of the K/T boundary impact  

NASA Technical Reports Server (NTRS)

All available evidence is consistent with an impact into oceanic crust terminating the Cretaceous Period. Although much of this evidence is incompatible with an endogenic origin, some investigators still feel that a volcanic origin is possible for the Cretaceous/Tertiary (K/T) boundary clay layers. The commonly cited evidence for a large impact stems from delicate clay layers and their components and the impact site has not yet been found. Impact sites have been suggested all over the globe. The impact is felt to have occurred near North America by: the occurrence of a 2 cm thick ejecta layer only at North American locales, the global variation of shocked quartz grain sizes peaking in North America, the global variation of spinel compositions with most refractory compositions occurring in samples from the Pacific region and possibly uniquely severe plant extinctions in the North American region. The K/T boundary interval was investigated as preserved on the banks of the Brazos River, Texas. The K/T fireball and ejecta layers with associated geochemical anomalies were found interbedded with this sequence which apparently allows a temporal resolution 4 orders of magnitude greater than typical K/T boundary sections. A literature search reveals that such coarse deposits are widely preserved at the K/T boundary. Impact wave deposits have not been found elsewhere on the globe, suggesting the impact occurred between North and South America. The coarse deposits preserved in Deep Sea Drilling Project (DSDP) holes 151-3 suggest the impact occurred nearby. Subsequent tectonism has complicated the picture.

Hildebrand, A. R.; Boynton, W. V.

1988-01-01

130

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

131

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

Microsoft Academic Search

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

132

Acoustic Kappa-Density Fluctuation Waves in Suprathermal Kappa Function Fluids  

E-print Network

We describe a new wave mode similar to the acoustic wave in which both density and velocity fluctuate. Unlike the acoustic wave in which the underlying distribution is Maxwellian, this new wave mode occurs when the underlying distribution is a suprathermal kappa function and involves fluctuations in the power law index, kappa. This wave mode always propagates faster than the acoustic wave with an equivalent effective temperature and becomes the acoustic wave in the Maxwellian limit as kappa goes to infinity.

Michael R. Collier; Aaron Roberts; Adolfo Vinas

2007-10-20

133

Phases of Augmented Hadronic Light-Front Wave Functions  

SciTech Connect

It is an important question whether the final/initial state gluonic interactions which lead to naive-time-reversal-odd single-spin asymmetries and diffraction at leading twist can be associated in a definite way with the light-front wave function hadronic eigensolutions of QCD. We use light-front time-ordered perturbation theory to obtain augmented light-front wave functions which contain an imaginary phase which depends on the choice of advanced or retarded boundary condition for the gauge potential in light-cone gauge. We apply this formalism to the wave functions of the valence Fock states of nucleons and pions, and show how this illuminates the factorization properties of naive-time-reversal-odd transverse momentum dependent observables which arise from rescattering. In particular, one calculates the identical leading-twist Sivers function from the overlap of augmented light-front wavefunctions that one obtains from explicit calculations of the single-spin asymmetry in semi-inclusive deep inelastic lepton-polarized nucleon scattering where the required phases come from the final-state rescattering of the struck quark with the nucleon spectators.

Yuan, Feng; Brodsky, S.J.; Pasquini, B.; Xiao, B.-W.

2010-01-05

134

Phases of Augmented Hadronic Light-Front Wave Functions  

SciTech Connect

It is an important question whether the final/initial state gluonic interactions which lead to naive-time-reversal-odd single-spin asymmetries and diffraction at leading twist can be associated in a definite way with the light-front wave function hadronic eigensolutions of QCD. We use light-front time-ordered perturbation theory to obtain augmented light-front wave functions which contain an imaginary phase which depends on the choice of advanced or retarded boundary condition for the gauge potential in light-cone gauge. We apply this formalism to the wave functions of the valence Fock states of nucleons and pions, and show how this illuminates the factorization properties of naive-time-reversal-odd transverse momentum dependent observables which arise from rescattering. In particular, one calculates the identical leading-twist Sivers function from the overlap of augmented light-front wavefunctions that one obtains from explicit calculations of the single-spin asymmetry in semi-inclusive deep inelastic lepton-polarized nucleon scattering where the required phases come from the final-state rescattering of the struck quark with the nucleon spectators.

Brodsky, Stanley J.; /SLAC; Pasquini, Barbara; /Pavia U. /INFN, Pavia; Xiao, Bo-Wen; /LBNL, NSD; Yuan, Feng; /LBNL, NSD /RIKEN BNL

2010-02-15

135

Modelling the nucleon wave function from soft and hard processes  

E-print Network

Current light-cone wave functions for the nucleon are unsatisfactory since they are in conflict with the data of the nucleon's Dirac form factor at large momentum transfer. Therefore, we attempt a determination of a new wave function respecting theoretical ideas on its parameterization and satisfying the following constraints: It should provide a soft Feynman contribution to the proton's form factor in agreement with data; it should be consistent with current parameterizations of the valence quark distribution functions and lastly it should provide an acceptable value for the $\\jp \\to N \\bar N$ decay width. The latter process is calculated within the modified perturbative approach to hard exclusive reactions. A simultaneous fit to the three sets of data leads to a wave function whose $x$-dependent part, the distribution amplitude, shows the same type of asymmetry as those distribution amplitudes constrained by QCD sum rules. The asymmetry is however much more moderate as in those amplitudes. Our distribution amplitude resembles the asymptotic one in shape but the position of the maximum is somewhat shifted.

J. Bolz; P. Kroll

1996-03-12

136

Phases of Augmented Hadronic Light-Front Wave Functions  

E-print Network

It is an important question whether the final/initial state gluonic interactions which lead to naive-time-reversal-odd single-spin asymmetries and diffraction at leading twist can be associated in a definite way with the light-front wave function hadronic eigensolutions of QCD. We use light-front time-ordered perturbation theory to obtain augmented light-front wave functions which contain an imaginary phase which depends on the choice of advanced or retarded boundary condition for the gauge potential in light-cone gauge. We apply this formalism to the wave functions of the valence Fock states of nucleons and pions, and show how this illuminates the factorization properties of naive-time-reversal-odd transverse momentum dependent observables which arise from rescattering. In particular, one calculates the identical leading-twist Sivers function from the overlap of augmented light-front wavefunctions that one obtains from explicit calculations of the single-spin asymmetry in semi-inclusive deep inelastic lepton-polarized nucleon scattering where the required phases come from the final-state rescattering of the struck quark with the nucleon spectators.

Stanley J. Brodsky; Barbara Pasquini; Bowen Xiao; Feng Yuan

2010-01-08

137

Theory of steady-state plane tunneling-assisted impact ionization waves  

SciTech Connect

The effect of band-to-band and trap-assisted tunneling on the properties of steady-state plane ionization waves in p{sup +}-n-n{sup +} structures is theoretically analyzed. It is shown that such tunneling-assisted impact ionization waves do not differ in a qualitative sense from ordinary impact ionization waves propagating due to the avalanche multiplication of uniformly distributed seed electrons and holes. The quantitative differences of tunneling-assisted impact ionization waves from impact ionization waves are reduced to a slightly different relation between the wave velocity u and the maximum field strength E{sub M} at the front. It is shown that disregarding impact ionization does not exclude the possibility of the existence of tunneling-assisted ionization waves; however, their structure radically changes, and their velocity strongly decreases for the same E{sub M}. A comparison of the dependences u(E{sub M}) for various ionization-wave types makes it possible to determine the conditions under which one of them is dominant. In conclusion, unresolved problems concerning the theory of tunneling-assisted impact ionization waves are discussed and the directions of further studies are outlined.

Kyuregyan, A. S., E-mail: ask@vei.ru [Lenin All-Russian Electrical-Engineering Institute (Russian Federation)

2013-07-15

138

Wave Propagation Experiments On Ballistically Impacted Composite Laminates  

Microsoft Academic Search

The details of the time history of the elastic waves in ballistically im pacted composite laminates have been obtained by using surface and em bedded strain gages. Records show that a very low-amplitude in-plane tensile wave arrives first followed by a medium-amplitude flexural wave and then a high-amplitude flexural wave. Measured and calculated values of wave speeds agree well.

Nobuo Takeda; Robert L. Sierakowski; Lawrence E. Malvern

1981-01-01

139

Wave function analysis of MHC-peptide interactions.  

PubMed

We have carried out an analysis of the wave function data for three MHC-peptide complexes: HLA-DRbeta1*0101-HA, HLA-DRbeta1*0401-HA and HLA-DRbeta1*0401-Col. We used quantum chemistry computer programs to generate wave function coefficients for these complexes, from which we obtained both molecular and atomic orbital data for both pocket and peptide amino acids within each pocket region. From these discriminated data, interaction molecular orbitals (IMOs) were identified as those with large and similar atomic orbital coefficient contributions from both pocket and peptide amino acids. The present results correlate well with our previous research where only electrostatic moments were used to explore molecular component interactions. Furthermore, we show a quantum chemical methodology to produce more fine-grained results concerning amino acid behavior in the MHC-peptide interaction. PMID:16793298

Cárdenas, Constanza; Obregón, Mateo; Balbín, Alejandro; Villaveces, José Luis; Patarroyo, Manuel E

2007-01-01

140

Horizon Wave-Function and the Quantum Cosmic Censorship  

E-print Network

We investigate the Cosmic Censorship Conjecture by means of the horizon wave-function (HWF) formalism. We consider a charged massive particle whose quantum mechanical state is represented by a spherically symmetric Gaussian wave-function, and restrict our attention to the superxtremal case (with charge-to-mass ratio $\\alpha>1$), which is the prototype of a naked singularity in the classical theory. We find that one can still obtain a normalisable HWF for $\\alpha^2 2$, and the uncertainty in the location of the horizon blows up at $\\alpha^2=2$, signalling that such an object is no more well-defined. This perhaps implies that a {\\em quantum\\/} Cosmic Censorhip might be conjectured by stating that no black holes with charge-to-mass ratio greater than a critical value (of the order of $\\sqrt{2}$) can exist.

Casadio, Roberto; Stojkovic, Dejan

2015-01-01

141

Horizon Wave-Function and the Quantum Cosmic Censorship  

E-print Network

We investigate the Cosmic Censorship Conjecture by means of the horizon wave-function (HWF) formalism. We consider a charged massive particle whose quantum mechanical state is represented by a spherically symmetric Gaussian wave-function, and restrict our attention to the superxtremal case (with charge-to-mass ratio $\\alpha>1$), which is the prototype of a naked singularity in the classical theory. We find that one can still obtain a normalisable HWF for $\\alpha^2 2$, and the uncertainty in the location of the horizon blows up at $\\alpha^2=2$, signalling that such an object is no more well-defined. This perhaps implies that a {\\em quantum\\/} Cosmic Censorhip might be conjectured by stating that no black holes with charge-to-mass ratio greater than a critical value (of the order of $\\sqrt{2}$) can exist.

Roberto Casadio; Octavian Micu; Dejan Stojkovic

2015-03-10

142

Spin-orbit decomposition of ab initio nuclear wave functions  

NASA Astrophysics Data System (ADS)

Although the modern shell-model picture of atomic nuclei is built from single-particle orbits with good total angular momentum j , leading to j -j coupling, decades ago phenomenological models suggested that a simpler picture for 0 p -shell nuclides can be realized via coupling of the total spin S and total orbital angular momentum L . I revisit this idea with large-basis, no-core shell-model calculations using modern ab initio two-body interactions and dissect the resulting wave functions into their component L - and S -components. Remarkably, there is broad agreement with calculations using the phenomenological Cohen-Kurath forces, despite a gap of nearly 50 years and six orders of magnitude in basis dimensions. I suggest that L -S decomposition may be a useful tool for analyzing ab initio wave functions of light nuclei, for example, in the case of rotational bands.

Johnson, Calvin W.

2015-03-01

143

Strongly correlated wave functions for artificial atoms and molecules  

E-print Network

A method for constructing semianalytical strongly correlated wave functions for single and molecular quantum dots is presented. It employs a two-step approach of symmetry breaking at the Hartree-Fock level and of subsequent restoration of total spin and angular momentum symmetries via Projection Techniques. Illustrative applications are presented for the case of a two-electron helium-like single quantum dot and a hydrogen-like quantum dot molecule.

Constantine Yannouleas; Uzi Landman

2002-08-27

144

A Polymer Expansion for the Quantum Heisenberg Ferromagnet Wave Function  

E-print Network

A polymer expansion is given for the Quantum Heisenberg Ferromagnet wave function. Working on a finite lattice, one is dealing entirely with algebraic identities; there is no question of convergence. The conjecture to be pursued in further work is that effects of large polymers are small. This is relevant to the question of the utility of the expansion and its possible extension to the infinite volume. In themselves the constructions of the present paper are neat and elegant and have surprising simplicity.

Paul Federbush

2003-04-02

145

Wave functions for the Schwarzschild black hole interior  

SciTech Connect

Using the Hamiltonian constraint derived by Ashtekar and Bojowald, we look for preclassical wave functions in the Schwarzschild interior. In particular, when solving this difference equation by separation of variables, an inequality is obtained relating the Immirzi parameter {gamma} to the quantum ambiguity {delta} appearing in the model. This bound is violated when we use a natural value for {delta} based on loop quantum gravity together with a recent proposal for {gamma}. We also present numerical solutions of the constraint.

Cartin, Daniel; Khanna, Gaurav [Naval Academy Preparatory School, 197 Elliot Street, Newport, Rhode Island 02841 (United States); Physics Department, University of Massachusetts at Dartmouth, North Dartmouth, Massachusetts 02747 (United States)

2006-05-15

146

Detecting topological order in a ground state wave function.  

PubMed

A large class of topological orders can be understood and classified using the string-net condensation picture. These topological orders can be characterized by a set of data (N, di, F(lmn)(ijk), delta(ijk). We describe a way to detect this kind of topological order using only the ground state wave function. The method involves computing a quantity called the "topological entropy" which directly measures the total quantum dimension D= Sum(id2i). PMID:16605803

Levin, Michael; Wen, Xiao-Gang

2006-03-24

147

Coevolution of Quantum Wave Functions and the Friedmann Universe  

E-print Network

Erwin Schrodinger (1939) proved that quantum wave functions coevolve with the curved spacetime of the Friedmann universe. Schrodinger's derivation explains the Hubble redshift of photons in an expanding universe, the energy changes of moving particles, and establishes the coevolution of atoms and other quantum systems with spacetime geometry. The assumption often made that small quantum systems are isolated and that their properties remain constant as the Friedmann universe evolves is incompatible with relativistic quantum mechanics and with general relativity.

W. Q. Sumner; D. Y. Sumner

2007-04-20

148

Simple Atomic Model and its Associated Wave Function  

Microsoft Academic Search

A simple atomic model, with features characteristic of the screening-theory approach, is constructed and provides simple analytic trial wave functions psit which describe the motion of the inner electrons particularly well. Basing our model on the energy-extremum principle, in contrast to a semiempirical or phenomenological approach, we can judge improvements in the model in a consistent manner. The single-particle orbitals

R. O. Mueller; A. R. Rau; Larry Spruch

1973-01-01

149

Interaction between light and matter: A photon wave function approach  

E-print Network

The Bialynicki-Birula-Sipe photon wave function formalism is extended to include the interaction between photons and continuous non-absorptive media. When the second quantization of this formalism is introduced, a new way of describing the quantum interactions between light and matter emerges. As an example of application, the quantum state of the twin photons generated by parametric down conversion is obtained in agreement with previous treatments, but with a more intuitive interpretation.

Pablo L. Saldanha; C. H. Monken

2011-06-14

150

The Second Moment of the Pion Light Cone Wave Function  

E-print Network

We present a preliminary result for second moment of the light cone wave function of the pion. This parameter is the subject of a discrepancy between theoretical predictions (coming from lattice and sum rules) and a recent experimental result (that remarkably agrees with purely perturbative predictions). In this work we exploit lattice hypercubic symmetries to remove power divergences and, moreover, implement a full 1-loop matching for all the contributing operators.

Luigi Del Debbio; Massimo Di Pierro; Alex Dougall

2002-11-21

151

The Born Oppenheimer wave function near level crossing  

E-print Network

The standard Born Oppenheimer theory does not give an accurate description of the wave function near points of level crossing. We give such a description near an isotropic conic crossing, for energies close to the crossing energy. This leads to the study of two coupled second order ordinary differential equations whose solution is described in terms of the generalized hypergeometric functions of the kind 0F3(;a,b,c;z). We find that, at low angular momenta, the mixing due to crossing is surprisingly large, scaling like \\mu^(1/6), where \\mu is the electron to nuclear mass ratio.

J. E. Avron; A. Gordon

2000-08-22

152

Measurement of the Pion and Photon Light-Cone Wave Functions by Diffractive Dissociation  

E-print Network

The measurement of the pion light-cone wave function is revisited and results for the Gegenbauer coefficients are presented. Mesurements of the photon electromagnetic and hadronic wave functions are described and results are presented.

Daniel Ashery

2005-11-24

153

Systematic theoretical investigation of the zero-field splitting in Gd(III) complexes: Wave function and density functional approaches  

NASA Astrophysics Data System (ADS)

The zero-field splitting (ZFS) of the electronic ground state in paramagnetic ions is a sensitive probe of the variations in the electronic and molecular structure with an impact on fields ranging from fundamental physical chemistry to medical applications. A detailed analysis of the ZFS in a series of symmetric Gd(III) complexes is presented in order to establish the applicability and accuracy of computational methods using multiconfigurational complete-active-space self-consistent field wave functions and of density functional theory calculations. The various computational schemes are then applied to larger complexes Gd(III)DOTA(H2O)-, Gd(III)DTPA(H2O)2-, and Gd(III)(H2O)83+ in order to analyze how the theoretical results compare to experimentally derived parameters. In contrast to approximations based on density functional theory, the multiconfigurational methods produce results for the ZFS of Gd(III) complexes on the correct order of magnitude.

Khan, Shehryar; Kubica-Misztal, Aleksandra; Kruk, Danuta; Kowalewski, Jozef; Odelius, Michael

2015-01-01

154

CUMULATIVE IMPACTS ON WATER QUALITY FUNCTIONS OF WETLANDS  

EPA Science Inventory

Cumulative impacts on the water quality function of wetlands are impacts whose total effect cannot be predicted from the sum of the effects of individual impacts. he wetland is not a simple filter; it embodies chemical, physical, and biotic processes that can detain, transform, r...

155

Computational aspects of the continuum quaternionic wave functions for hydrogen  

NASA Astrophysics Data System (ADS)

Over the past few years considerable attention has been given to the role played by the Hydrogen Continuum Wave Functions (HCWFs) in quantum theory. The HCWFs arise via the method of separation of variables for the time-independent Schrödinger equation in spherical coordinates. The HCWFs are composed of products of a radial part involving associated Laguerre polynomials multiplied by exponential factors and an angular part that is the spherical harmonics. In the present paper we introduce the continuum wave functions for hydrogen within quaternionic analysis ((R)QHCWFs), a result which is not available in the existing literature. In particular, the underlying functions are of three real variables and take on either values in the reduced and full quaternions (identified, respectively, with R3 and R4). We prove that the (R)QHCWFs are orthonormal to one another. The representation of these functions in terms of the HCWFs are explicitly given, from which several recurrence formulae for fast computer implementations can be derived. A summary of fundamental properties and further computation of the hydrogen-like atom transforms of the (R)QHCWFs are also discussed. We address all the above and explore some basic facts of the arising quaternionic function theory. As an application, we provide the reader with plot simulations that demonstrate the effectiveness of our approach. (R)QHCWFs are new in the literature and have some consequences that are now under investigation.

Morais, J.

2014-10-01

156

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

NASA Astrophysics Data System (ADS)

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.

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

2014-03-01

157

Spatial impacts of heat waves in mortality. Evaluating current risks and future threats  

Microsoft Academic Search

Impacts of heat waves in morbidity and mortality are largely known. Climate Change is expected to increase the climate health impacts in summer while the winter will be probably favored. The health impacts of extreme thermal events are mainly studied at a national or regional level, considering macro or mesoscale thermal features. But it can be assumed that local variations

H. Andrade; P. Canario; H. Nogueira

2009-01-01

158

Stress wave propagation in a composite beam subjected to transverse impact.  

SciTech Connect

Composite materials, particularly fiber reinforced plastic composites, have been extensively utilized in many military and industrial applications. As an important structural component in these applications, the composites are often subjected to external impact loading. It is desirable to understand the mechanical response of the composites under impact loading for performance evaluation in the applications. Even though many material models for the composites have been developed, experimental investigation is still needed to validate and verify the models. It is essential to investigate the intrinsic material response. However, it becomes more applicable to determine the structural response of composites, such as a composite beam. The composites are usually subjected to out-of-plane loading in applications. When a composite beam is subjected to a sudden transverse impact, two different kinds of stress waves, longitudinal and transverse waves, are generated and propagate in the beam. The longitudinal stress wave propagates through the thickness direction; whereas, the propagation of the transverse stress wave is in-plane directions. The longitudinal stress wave speed is usually considered as a material constant determined by the material density and Young's modulus, regardless of the loading rate. By contrast, the transverse wave speed is related to structural parameters. In ballistic mechanics, the transverse wave plays a key role to absorb external impact energy [1]. The faster the transverse wave speed, the more impact energy dissipated. Since the transverse wave speed is not a material constant, it is not possible to be calculated from stress-wave theory. One can place several transducers to track the transverse wave propagation. An alternative but more efficient method is to apply digital image correlation (DIC) to visualize the transverse wave propagation. In this study, we applied three-pointbending (TPB) technique to Kolsky compression bar to facilitate dynamic transverse loading on a glass fiber/epoxy composite beam. The high-speed DIC technique was employed to study the transverse wave propagation.

Lu, Wei-Yang; Song, Bo; Jin, Huiqing

2010-08-01

159

IMPACTS OF URBANIZATION ON WATERSHED HYDROLOGIC FUNCTION  

Technology Transfer Automated Retrieval System (TEKTRAN)

Although urbanization has a major impact on watershed hydrology, there have not been studies to quantify basic hydrological relationships are altered by the addition of impervious surfaces. The USDA-ARS and USEPA-ORD-NRMRL have initiated a pilot program to study the impacts of different extents and...

160

IMPACTS OF URBANIZATION ON WATERSHED HYDROLOGIC FUNCTION  

EPA Science Inventory

Although urbanization has a major impact on watershed hydrology, there have not been studies to quantify basic hydrological relationships that are altered by the addition of impervious surfaces. The USDA-ARS and USEPA-ORD-NRMRL have initiated a pilot program to study the impacts...

161

Trial Wave Function for Particle in Slanted Box Trial wave functions: 1 x( ) 2 sin x( ):= 2 x( ) 105 x 1 x-( )  

E-print Network

Trial Wave Function for Particle in Slanted Box Trial wave functions: 1 x( ) 2 sin x( ):= 2 x( ) 105 x 1 x-( ) 2 := Plot trial wave functions and potential energy. x 0 .005, 1..:= 0 0.5 1 0 0.5 1 1 of the particle in the box: 0 1 xx x( ) 2 d 0.496= Calculate the probability that the particle is in the left

Rioux, Frank

162

The impact energy of a moored tanker under the action of regular waves  

SciTech Connect

The influence that factors such as mooring line conditions, fender arrangements, dolphin arrangements, degree of ship loading, waves of long period, wave direction, and wind on the impact energy of a moored tanker were studied. Based on systematic test data, a semi-empirical formula was developed to calculate the impact energy of the moored ship on the berthing facilities under the action of regular waves. It was shown by experiment that this method is suitable for calculating the impact energy of moored ships of capacities as great as 200 X 10/sup 3/ t.

Yu-Cheng Li

1982-09-01

163

Orbital dependent functionals: An atom projector augmented wave method implementation  

NASA Astrophysics Data System (ADS)

This thesis explores the formulation and numerical implementation of orbital dependent exchange-correlation functionals within electronic structure calculations. These orbital-dependent exchange-correlation functionals have recently received renewed attention as a means to improve the physical representation of electron interactions within electronic structure calculations. In particular, electron self-interaction terms can be avoided. In this thesis, an orbital-dependent functional is considered in the context of Hartree-Fock (HF) theory as well as the Optimized Effective Potential (OEP) method and the approximate OEP method developed by Krieger, Li, and Iafrate, known as the KLI approximation. In this thesis, the Fock exchange term is used as a simple well-defined example of an orbital-dependent functional. The Projected Augmented Wave (PAW) method developed by P. E. Blochl has proven to be accurate and efficient for electronic structure calculations for local and semi-local functions because of its accurate evaluation of interaction integrals by controlling multiple moments. We have extended the PAW method to treat orbital-dependent functionals in Hartree-Fock theory and the Optimized Effective Potential method, particularly in the KLI approximation. In the course of study we develop a frozen-core orbital approximation that accurately treats the core electron contributions for above three methods. The main part of the thesis focuses on the treatment of spherical atoms. We have investigated the behavior of PAW-Hartree Fock and PAW-KLI basis, projector, and pseudopotential functions for several elements throughout the periodic table. We have also extended the formalism to the treatment of solids in a plane wave basis and implemented PWPAW-KLI code, which will appear in future publications.

Xu, Xiao

164

The "JK-only" approximation in density matrix functional and wave function theory.  

PubMed

Various energy functionals applying the "JK-only" approximation which leads to two-index two-electron integrals instead of four-index two-electron integrals in the electron-electron interaction term of the electronic energy are presented. Numerical results of multiconfiguration self-consistent field calculations for the best possible "JK-only" wave function are compared to those obtained from the pair excitation multiconfiguration self-consistent (PEMCSCF) method and two versions of density matrix functional theory. One of these is derived making explicit use of some necessary conditions for N representability of the second-order density matrix. It is shown that this method models the energy functional based on the best possible "JK-only" wave function with good accuracy. The calculations also indicate that only a minor fraction of the total correlation energy is incorporated by "JK-only" approaches for larger molecules. PMID:15634123

Kollmar, Christian

2004-12-15

165

Particle-in-cell simulation study of the impact of ion cyclotron waves on auroral kilometric radiation  

Microsoft Academic Search

We will present results of 2 1\\/2-dimensional particle-in-cell simulations where the impact of ion cyclotron waves on auroral kilometric radiation (AKR) has been studied. A horseshoe electron distribution function in a strong magnetic field is unstable to modes with frequencies slightly below the electron cyclotron frequency and can generate AKR. In the presence of an electron beam superimposed on the

N. Bessho; J. D. Menietti

2007-01-01

166

Wave-function monopoles in Bose-Einstein condensates  

NASA Astrophysics Data System (ADS)

Experimental preparation of multispecies Bose-Einstein condensates should permit the creation of topologically stable defects beyond the superfluid vortex. But the coldness and isolation of condensates should also permit the survival for observable durations of ``pseudodefects,'' such as the one-dimensional dark soliton: localized structures related to a defect but not topologically stable. In this paper we investigate the viability of pseudodefects beyond one dimension, by examining ``wave-function monopoles'' in two-species condensates in two dimensions. We identify interesting instabilities, including a ``dancing mode'' for monopoles of higher winding number, and (in a one-dimensional limit) ``superfluid roulette.''

Busch, Th.; Anglin, J. R.

1999-10-01

167

Relativistic Covariance and Quark-Diquark Wave Functions  

E-print Network

We derive covariant wave functions for hadrons composed of two constituents for arbitrary Lorentz boosts. Focussing explicitly on baryons as quark-diquark systems, we reduce their manifestly covariant Bethe-Salpeter equation to covariant 3-dimensional forms by projecting on the relative quark-diquark energy. Guided by a phenomenological multi gluon exchange representation of covariant confining kernels, we derive explicit solutions for harmonic confinement and for the MIT Bag Model. We briefly sketch implications of breaking the spherical symmetry of the ground state and the transition from the instant form to the light cone via the infinite momentum frame.

M. Dillig

2006-04-24

168

Resonance wave functions located at the Stark saddle point  

NASA Astrophysics Data System (ADS)

We calculate quantum-mechanically exact wave functions of resonances in spectra of the hydrogen atom in crossed external fields and prove the existence of long-lived decaying quantum states localized at the Stark saddle point. A spectrum of ground and excited states reproducing the nodal patterns expected from simple quadratic and cubic expansions of the potential in the vicinity of the saddle point can be identified. The results demonstrate the presence of resonances in the vicinity of the saddle predicted by simple approximations.

Cartarius, Holger; Main, Jörg; Losch, Thorsten; Wunner, Günter

2010-06-01

169

Is spontaneous wave function collapse testable at all?  

E-print Network

Mainstream literature on spontaneous wave function collapse never reflects on or profit from the formal coincidence and conceptual relationship with standard collapse under time-continuous quantum measurement (monitoring). I propose some easy lessons of standard monitoring theory which would make spontaneous collapse models revise some of their claims. In particular, the objective detection of spontaneous collapse remains impossible as long as the correct identification of what corresponds to the signal in standard monitoring is missing from spontaneous collapse models, the physical detectability of the "signal" is not stated explicitly and, finally, the principles of physical detection are not revealed.

Lajos Diósi

2015-03-16

170

Electromagnetism and multiple-valued loop-dependent wave functionals  

E-print Network

We quantize the Maxwell theory in the presence of a electric charge in a "dual" Loop Representation, i.e. a geometric representation of magnetic Faraday's lines. It is found that the theory can be seen as a theory without sources, except by the fact that the wave functional becomes multivalued. This can be seen as the dual counterpart of what occurs in Maxwell theory with a magnetic pole, when it is quantized in the ordinary Loop Representation. The multivaluedness can be seen as a result of the multiply-connectedness of the configuration space of the quantum theory.

Lorenzo Leal

2009-10-14

171

Ocean wave-radar modulation transfer functions from the west coast experiment  

Microsoft Academic Search

Short gravity-capillary waves, the equilibrium, or the steady state excitations of the ocean surface are modulated by longer ocean waves. These short waves are the predominant microwave scatterers on the ocean surface under many viewing conditions so that the modulation is readily measured with CW Doppler radar used as a two-scale wave probe. Modulation transfer functions (the ratio of the

J. W. Wright; W. J. Plant; W. C. Keller; W. L. Jones

1980-01-01

172

Ocean Wave-Radar Modulation Transfer Functions From the West Coast Experiment  

Microsoft Academic Search

Short gravity-capillary waves, the equilibrium, or the steady state excitations of the ocean surface are modulated by longer ocean waves. These short waves are the predominant microwave scatterers on the ocean surface under many viewing conditions so that the modulation is readily measured with CW Doppler radar used as a two-scale wave probe. Modulation transfer functions (the ratio of the

J. W. Wright; W. J. Plant; W. C. Keller; W. L. Jones

1980-01-01

173

Impact of Stone Removal on Renal Function: A Review  

PubMed Central

Stone removal can improve renal function by eradicating obstruction and, in certain cases, an underlying infection. Stone-removing procedures, however, may negatively impact functional integrity. Many things may impact the latter, including the procedures used, the methods of assessing function, the time when these assessments are made, the occurrence of complications, the baseline condition of the kidney, and patient-related factors. In the majority of cases, little significant functional impairment occurs. However, there are gaps in our knowledge of this subject, including the cumulative effects of multiple procedures violating the renal parenchyma and long-term functional outcomes. PMID:21935339

Wood, Kyle; Keys, Tristan; Mufarrij, Patrick; Assimos, Dean G

2011-01-01

174

Molecular dynamics study of shock wave generation by cluster impact on solid targets  

Microsoft Academic Search

The generation of shock waves by energetic gas cluster impact on a solid surface was studied by use of two-dimensional (2D) molecular dynamics. The collisions of Arn (n ? 200–350) clusters with the target of 40 000 atoms were modeled. The atomic scale shock waves arising from cluster impact have been obtained by calculating the pressure, temperature and mass-velocity of

Z. Insepov; I. Yamada

1996-01-01

175

The impact of heat waves and cold spells on mortality rates in the Dutch population  

Microsoft Academic Search

We conducted the study described in this paper to investigate the impact of ambient temperature on mortality in the Netherlands during 1979-1997, the impact of heat waves and cold spells on mortality in particular, and the possibility of any heat wave- or cold spell-induced forward dis- placement of mortality. We found a V-like relationship between mortality and temperature, with an

Maud M. T. E. Huynen; P Martens; Dieneke Schram; Matty P. Weijenberg; Anton E. Kunst

2001-01-01

176

Impact of a coupled ocean wave–tide–circulation system on coastal modeling  

Microsoft Academic Search

The impact of a coupled ocean wave–tide–circulation system on coastal modeling for wind waves, oceanic circulation, and water-mass simulation is investigated by coupling of two well-tested models: the third-generation wave model (WAVEWATCH-II) and the Princeton ocean model (POM). In this study, several numerical experiments in the Yellow and East China Sea (YECS) are performed for the ideal winter case and

Il-Ju Moon

2005-01-01

177

The stability of freak waves with regard to external impact and perturbation of initial data  

NASA Astrophysics Data System (ADS)

We investigate solutions of the equations, describing freak waves, in perspective of stability with regard to external impact and perturbation of initial data. The modeling of freak waves is based on numerical solution of equations describing a non-stationary potential flow of the ideal fluid with a free surface. We consider the two-dimensional infinitely deep flow. For waves modeling we use the equations in conformal variables. The variant of these equations is offered in [1]. Mathematical correctness of these equations was discussed in [2]. These works establish the uniqueness of solutions, offer the effective numerical solution calculation methods, prove the numerical convergence of these methods. The important aspect of numerical modeling of freak waves is the stability of solutions, describing these waves. In this work we study the questions of stability with regards to external impact and perturbation of initial data. We showed the stability of freak waves numerical model, corresponding to the external impact. We performed series of computational experiments with various freak wave initial data and random external impact. This impact means the power density on free surface. In each experiment examine two waves: the wave that was formed by external impact and without one. In all the experiments we see the stability of equation`s solutions. The random external impact practically does not change the time of freak wave formation and its form. Later our work progresses to the investigation of solution's stability under perturbations of initial data. We take the initial data that provide a freak wave and get the numerical solution. In common we take the numerical solution of equation with perturbation of initial data. The computing experiments showed that the freak waves equations solutions are stable under perturbations of initial data.So we can make a conclusion that freak waves are stable relatively external perturbation and perturbation of initial data both. 1. Zakharov V.E., Dyachenko A.I., Vasilyev O.A. New method for numerical simulation of a nonstationary potential flow of incompressible fluid with a free surface// Eur. J.~Mech. B Fluids. 2002. V. 21. P. 283-291. 2. R.V. Shamin. Dynamics of an Ideal Liquid with a Free Surface in Conformal Variables // Journal of Mathematical Sciences, Vol. 160, No. 5, 2009. P. 537-678. 3. R.V. Shamin, V.E. Zakharov, A.I. Dyachenko. 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

Smirnova, Anna; Shamin, Roman

2014-05-01

178

Phase-space manipulations of many-body wave functions  

NASA Astrophysics Data System (ADS)

We explore the manipulation in phase space of many-body wave functions that exhibit self-similar dynamics under the application of sudden force and/or in the presence of a constant acceleration field. For this purpose, we work out a common theoretical framework based on the Wigner function. We discuss squeezing in position space, phase-space rotation, and its implications in cooling for both noninteracting and interacting gases and time-reversal operation. We discuss various optical analogies and calculate the role of a spherical-like aberration in cooling protocols. We also present the equivalent of a spin-echo technique to improve the robustness of velocity dispersion reduction protocols.

Condon, G.; Fortun, A.; Billy, J.; Guéry-Odelin, D.

2014-12-01

179

Heat Wave Hazards: An Overview of Heat Wave Impacts in Canada  

Microsoft Academic Search

Extreme heat events are natural hazards affecting Canada and many other regions of the world. This paper presents an overview of the issues involved in defining heat waves and harmful hot weather events, followed by a spatial and historical overview of heat waves across Canada, and an assessment of heat wave adaptation potential in selected cities. The Prairies, Southern Ontario,

Karen E. Smoyer-Tomic; Robyn Kuhn; Alana Hudson

2003-01-01

180

Standing wave vs Green's function approach to the Casimir force problem Frdric Schuller1  

E-print Network

1 Standing wave vs Green's function approach to the Casimir force problem Frédéric Schuller1 standing wave approach to the Casimir force problem, we consider Lifshitz's temperature Green's function and z = a. The standing wave calculation In [5] we consider the following expression for the field

Boyer, Edmond

181

Heat wave impacts on mortality in Shanghai, 1998 and 2003  

Microsoft Academic Search

A variety of research has linked extreme heat to heightened levels of daily mortality and, not surprisingly, heat waves both in 1998 and in 2003 all led to elevated mortality in Shanghai, China. While the heat waves in the two years were similar in meteorological character, elevated mortality was much more pronounced during the 1998 event, but it remains unclear

Jianguo Tan; Youfei Zheng; Guixiang Song; Laurence S. Kalkstein; Adam J. Kalkstein; Xu Tang

2007-01-01

182

Insights Into Caribbean Lithospheric Structure From S Wave Receiver Functions  

NASA Astrophysics Data System (ADS)

BOLIVAR (Broadband Ocean-Land Investigation of Venezuela and the Antilles arc Region) was aimed at investigating the interplay between the lithospheric and asthenospheric mantle of the Caribbean and the South America plates. The oblique collision of the Caribbean plate migrating eastwards has created a complicated deformation zone with strike-slip, compressional and extensional structures along the Caribbean and South America boundary. Earlier results with P receiver functions revealed strong variations in crustal thickness ranging from 15 km beneath the Caribbean Sea to 55 km beneath Venezuela. However, one of the fundamental questions not yet resolved concerns the thickness of the lithosphere in this region. Using the S wave receiver function technique, we analyzed seismograms from some 100 events at epicentral distances of 55-125 degree. The seismograms were rotated and deconvolved to isolate S-to-P conversions from the incident S wave. These were subsequently stacked after their respective conversion points and mapped into the subsurface. A strong negative phase is associated with the S-to-P conversion from the base of the lithosphere. Analysis of these data is ongoing, but we expect to see large variation in lithospheric thickness as the BOLIVAR array spans the transition from the Caribbean with OBS stations to the interior of South America (Guyana Shield).

Landes, M.; Pavlis, G. L.

2007-12-01

183

Impact of fMRI Environment on Cognitive Function   

E-print Network

Functional magnetic resonance imaging (fMRI) is an increasingly important tool in psychological research, but its reliability is somewhat undermined by concerns about the fMRI environment’s impact on cognition. The unusual scanner environment...

Sim, Tony

2011-01-01

184

[Impact of thyroid function on fertility].  

PubMed

Until recently, anovulation or recurrent miscarriages were the only situations for screening a thyroid dysfunction in an infertile patient. Recent U.S. guidelines published in 2011 identify infertile women as being at risk for thyroid dysfunction. This paper proposes, on the occasion of the new recommendations, a review of the literature data on the known impact of thyroid dysfunction on fertility, on the first trimester of pregnancy and on the way to treat them. PMID:25724447

Gronier, H; Sonigo, C; Jacquesson, L

2015-03-01

185

On the hydrogen wave function in Momentum-space, Clifford algebra and the Generating function of Gegenbauer polynomial  

E-print Network

Using the quadratic transformation and the generating function method we Perform the Fourier transformation of the wave function of coordinates of hydrogen atom and we find the analytic expression of the wave function in momentum space. We derive the matrix elements between the basis to 4-dimensions and integral representation of the generating functions of Gegenbauer polynomials. We find a relationship between a class of Clifford algebra and the generating functions of these polynomials.

Mehdi Hage-Hassan

2008-07-25

186

The environmental impact of a Wave Dragon array operating in the Black Sea.  

PubMed

The present work describes a study related to the influence on the shoreline dynamics of a wave farm consisting of Wave Dragon devices operating in the western side of the Black Sea. Based on historical data analysis of the wave climate, the most relevant environmental conditions that could occur were defined, and for these cases, simulations with SWAN spectral phase averaged wave model were performed. Two situations were considered for the most representative patterns: model simulations without any wave energy converter and simulations considering a wave farm consisting of six Wave Dragon devices. Comparisons of the wave model outputs have been carried out in both geographical and spectral spaces. The results show that although a significant influence appears near the wave farm, this gradually decreases to the coast line level. In order to evaluate the influence of the wave farm on the longshore currents, a nearshore circulation modeling system was used. In relative terms, the longshore current velocities appear to be more sensitive to the presence of the wave farm than the significant wave height. Finally, the possible impact on the marine flora and fauna specific to the target area was also considered and discussed. PMID:23844401

Diaconu, Sorin; Rusu, Eugen

2013-01-01

187

The Environmental Impact of a Wave Dragon Array Operating in the Black Sea  

PubMed Central

The present work describes a study related to the influence on the shoreline dynamics of a wave farm consisting of Wave Dragon devices operating in the western side of the Black Sea. Based on historical data analysis of the wave climate, the most relevant environmental conditions that could occur were defined, and for these cases, simulations with SWAN spectral phase averaged wave model were performed. Two situations were considered for the most representative patterns: model simulations without any wave energy converter and simulations considering a wave farm consisting of six Wave Dragon devices. Comparisons of the wave model outputs have been carried out in both geographical and spectral spaces. The results show that although a significant influence appears near the wave farm, this gradually decreases to the coast line level. In order to evaluate the influence of the wave farm on the longshore currents, a nearshore circulation modeling system was used. In relative terms, the longshore current velocities appear to be more sensitive to the presence of the wave farm than the significant wave height. Finally, the possible impact on the marine flora and fauna specific to the target area was also considered and discussed. PMID:23844401

Rusu, Eugen

2013-01-01

188

Colombian ocean waves and coasts modeled by special functions  

NASA Astrophysics Data System (ADS)

Modeling the ocean bottom and surface of both Atlantic and Pacific Oceans near the Colombian coast is a subject of increasing attention due to the possibility of finding oil deposits that haven't been discovered, and as a way of monitoring the ocean limits of Colombia with other countries not only covering the possibility of naval intrusion but as a chance to detect submarine devices that are used by illegal groups for different unwished purposes. In the development of this topic it would be necessary to use Standard Hydrodynamic Equations to model the mathematical shape of ocean waves that will take differential equations forms. Those differential equations will be solved using computer algebra software and methods. The mentioned solutions will involve the use of Special Functions such as Bessel Functions, Whittaker, Heun, and so on. Using the Special Functions mentioned above, the obtained results will be simulated by numerical methods obtaining the typical patterns around the Colombian coasts (both surface and bottom). Using this simulation as a non-perturbed state, any change in the patter could be taken as an external perturbation caused by a strange body or device in an specific area or region modeled, building this simulation as an ocean radar or an unusual object finder. It's worth mentioning that the use of stronger or more rigorous methods and more advanced Special Functions would generate better theoretical results, building a more accurate simulation model that would lead to a finest detection.

Duque Tisnés, Simón

2013-06-01

189

Pulse Wave Velocity and Cognitive Function in Older Adults  

PubMed Central

Arterial stiffness may be associated with cognitive function. In this study, pulse wave velocity (PWV) was measured from the carotid to femoral (CF-PWV) and from the carotid to radial (CR-PWV) with the Complior SP System (Alam Medical, Vincennes, France). Cognitive function was measured by six tests of executive function, psychomotor speed, memory, and language fluency. A total of 1433 participants were included (mean age 75 years, 43% men). Adjusting for age, sex, education, pulse rate, hemoglobin A1C, HDL cholesterol, hypertension, CVD history, smoking ,drinking, and depression symptoms, a CF-PWV > 12 m/s was associated with a lower Mini-Mental State Examination score (coefficient: ?0.31, se: 0.11, p=0.005), fewer words recalled on Auditory Verbal Learning Test (coefficient: ?1.10, se: 0.43, p=0.01), and lower score on the composite cognition score (coefficient: ?0.10, se: 0.05, p=0.04) and marginally significantly associated with longer time to complete Trail Making Test-B (coefficient: 6.30, se: 3.41, p=0.06), CF-PWV was not associated with Trail Making Test-A, Digit Symbol Substation Test, or Verbal Fluency Test. No associations were found between CR-PWV and cognitive performance measures. Higher large artery stiffness was associated with worse cognitive function, and longitudinal studies are needed to confirm these associations. PMID:23632267

Zhong, Wenjun; Cruickshanks, Karen J; Schubert, Carla R; Carlsson, Cynthia M; Chappell, Richard J; Klein, Barbara EK; Klein, Ronald; Acher, Charles W

2013-01-01

190

Pulse wave velocity and cognitive function in older adults.  

PubMed

Arterial stiffness may be associated with cognitive function. In this study, pulse wave velocity (PWV) was measured from the carotid to femoral (CF-PWV) and from the carotid to radial (CR-PWV) with the Complior SP System. Cognitive function was measured by 6 tests of executive function, psychomotor speed, memory, and language fluency. A total of 1433 participants were included (mean age 75 y, 43% men). Adjusting for age, sex, education, pulse rate, hemoglobin A1C, high-density lipoprotein cholesterol, hypertension, cardiovascular disease history, smoking, drinking, and depression symptoms, a CF-PWV>12 m/s was associated with a lower Mini-Mental State Examination score (coefficient: -0.31, SE: 0.11, P=0.005), fewer words recalled on Auditory Verbal Learning Test (coefficient: -1.10, SE: 0.43, P=0.01), and lower score on the composite cognition score (coefficient: -0.10, SE: 0.05, P=0.04) and marginally significantly associated with longer time to complete Trail Making Test-part B (coefficient: 6.30, SE: 3.41, P=0.06), CF-PWV was not associated with Trail Making Test-part A, Digit Symbol Substation Test, or Verbal Fluency Test. No associations were found between CR-PWV and cognitive performance measures. Higher large artery stiffness was associated with worse cognitive function, and longitudinal studies are needed to confirm these associations. PMID:23632267

Zhong, Wenjun; Cruickshanks, Karen J; Schubert, Carla R; Carlsson, Cynthia M; Chappell, Richard J; Klein, Barbara E K; Klein, Ronald; Acher, Charles W

2014-01-01

191

Jastrow wave functions for closed-shell atoms  

SciTech Connect

A linked-cluster expansion that has been derived previously to calculate expectation values for Jastrow-type wave functions is applied to variational calculations for closed-shell atoms. In the calculation the Hartree-Fock ground state is multiplied by a correlating factor Pig(r/sub i/)Pif(r/sub i/j) and the functions f and g determined variationally. Only the lowest-order direct terms are included in the calculation so that the variational principle is not strictly valid. The calculation is carried out in momentum space in order to simplify the treatment of the kinetic energy operator. The variational principle leads to a Fredholm equation of the first kind for the correlating factor. Parametrized forms of the correlating factor are given for the cases considered. It is found that the direct terms calculated overestimate the correlation energy of the atoms considered but estimates of the exchange terms indicate that these would largely account for the differences. It is found that it is not adequate to include only the two-particle functions f in the correlating factor, but the one-particle function g must also be included. The atoms considered are He, Be, Ne, Mg, and Ar.

Talman, J.D.

1980-06-01

192

Coupling of surge and waves for an Ivan-like hurricane impacting the Tampa Bay, Florida region  

Microsoft Academic Search

The interactions between waves and storm surge are investigated using an unstructured grid, coupled wave-surge model forced by a hypothetical Ivan-like hurricane impacting the Tampa Bay, Florida region. The waves derived from the unstructured version of the third-generation wave model simulating waves nearshore. The surge derives from the unstructured Finite-Volume Coastal Ocean Model, to which wave-induced forces (based on radiation

Yong Huang; Robert H. Weisberg; Lianyuan Zheng

2010-01-01

193

SH Wave Number Green's Function for a Layered, Elastic Half-Space. Part I: Theory and Dynamic Canyon Response by the Discrete Wave Number Boundary Element Method  

NASA Astrophysics Data System (ADS)

We present a closed-form frequency-wave number ( ? - k) Green's function for a layered, elastic half-space under SH wave propagation. It is shown that for every ( ? - k) pair, the fundamental solution exhibits two distinctive features: (1) the original layered system can be reduced to a system composed by the uppermost superficial layer over an equivalent half-space; (2) the fundamental solution can be partitioned into three different fundamental solutions, each one carrying out a different physical interpretation, i.e., an equivalent half-space, source image impact, and dispersive wave effect, respectively. Such an interpretation allows the proper use of analytical and numerical integration schemes, and ensures the correct assessment of Cauchy principal value integrals. Our method is based upon a stiffness-matrix scheme, and as a first approach we assume that observation points and the impulsive SH line-source are spatially located within the uppermost superficial layer. We use a discrete wave number boundary element strategy to test the benefits of our fundamental solution. We benchmark our results against reported solutions for an infinitely long circular canyon subjected to oblique incident SH waves within a homogeneous half-space. Our results show an almost exact agreement with previous studies. We further shed light on the impact of horizontal strata by examining the dynamic response of the circular canyon to oblique incident SH waves under different layered half-space configurations and incident angles. Our results show that modifications in the layering structure manifest by larger peak ground responses, and stronger spatial variability due to interactions of the canyon geometry with trapped Love waves in combination with impedance contrast effects.

Restrepo, Doriam; Gómez, Juan David; Jaramillo, Juan Diego

2014-09-01

194

The effect of wave function orthogonality on the simultaneous ionization and excitation of helium  

NASA Astrophysics Data System (ADS)

Within the framework of the first-order Born approximation, the triple differential cross sections (TDCSs) for simultaneous ionization and excitation of helium are calculated. The wave function of the ejected electron is chosen to be orthogonal or non-orthogonal to the wave function of the bound electron before ionization. It is found that the orthogonality has a strong effect on the TDCS, especially when plane waves and Coulomb waves are used to describe the projectile and the ejected electron.

Liu, Li-Juan; Jia, Chang-Chun; Zhang, Li-Min; Chen, Jiao-Jiao; Chen, Zhang-Jin

2013-10-01

195

Heat wave impacts on mortality in Shanghai, 1998 and 2003  

Microsoft Academic Search

A variety of research has linked extreme heat to heightened levels of daily mortality and, not surprisingly, heat waves both\\u000a in 1998 and in 2003 all led to elevated mortality in Shanghai, China. While the heat waves in the two years were similar in\\u000a meteorological character, elevated mortality was much more pronounced during the 1998 event, but it remains unclear

Jianguo Tan; Youfei Zheng; Guixiang Song; Laurence S. Kalkstein; Adam J. Kalkstein; Xu Tang

2007-01-01

196

Research The Impact of Heat Waves on Mortality in Seven Major Cities in Korea  

E-print Network

Bac k g r o u n d: Understanding the health impacts of heat waves is important, especially given anticipated increases in the frequency, duration, and intensity of heat waves due to climate change. Objectives: We examined mortality from heat waves in seven major Korean cities for 2000 through 2007 and investigated effect modification by individual characteristics and heat wave characteristics (intensity, duration, and timing in season). Met h o d s: Heat waves were defined as ? 2 consecutive days with daily mean temperature at or above the 98th percentile for the warm season in each city. We compared mortality during heatwave days and non-heat-wave days using city-specific generalized linear models. We used Bayesian hierarchical models to estimate overall effects within and across all cities. In addition, we estimated effects of heat wave characteristics and effects according to cause of death and examined effect modification by individual characteristics for Seoul. Res u l t s: Overall, total mortality increased 4.1 % [95 % confidence interval (CI): –6.1%, 15.4%] during heat waves compared with non-heat-wave days, with an 8.4 % increase (95 % CI: 0.1%, 17.3%) estimated for Seoul. Estimated mortality was higher for heat waves that were more intense, longer, or earlier in summer, although effects were not statistically significant. Estimated risks were higher for women versus men, older versus younger residents, those with no education versus some education, and deaths that occurred out of hospitals in Seoul, although differences among strata of individual characteristics were not statistically significant. Co n c l u s i o n s: Our findings support evidence of mortality impacts from heat waves and have implications for efforts to reduce the public health burden of heat waves. Key w o r d s: climate change, effect modification, extreme temperature, heat wave, mortality.

Ji-young Son; Jong-tae Lee; G. Brooke Anderson; Michelle L. Bell

2012-01-01

197

The Use of Gaussian (Exponential Quadratic) Wave Functions in Molecular Problems. II. Wave Functions for the Ground States of the Hydrogen Atom and of the Hydrogen Molecule  

Microsoft Academic Search

The results reported in this paper constitute a first examination of the use of Gaussian wave functions with correlation as approximations to electronic wave functions. Functions of the form sumk=nk=1 C_k exp (-Q_k), where C_k is a constant and Q_k is a quadratic form corresponding to orbitals with cylindrical symmetry, variable centres and with correlation, are used for the hydrogen

J. V. L. Longstaff; K. Singer

1960-01-01

198

Impact of Surface Waves on the Steady Near-Surface Wind Profiles over the Ocean  

NASA Astrophysics Data System (ADS)

The impacts of surface waves on the steady near-surface wind profiles in the marine atmospheric boundary layer (ABL) are studied based on the Ekman theory, modified by introducing a wave-induced component on the total stress. An analytic solution is presented for the wave-modified Ekman model for an eddy viscosity coefficient varying linearly with height. The solution can be determined by the two-dimensional wavenumber spectrum of ocean waves, the wave-growth or decay rate, the geostrophic wind velocity, the Coriolis parameter and the densities of air and water. Wind profiles are calculated as examples for two cases: one with a monochromatic wave and the other with a fully-developed wind-generated sea. The effects of the surface waves on the wind profiles in the marine ABL are illustrated, and solutions proposed are compared with those of the model where the wave-induced stress is neglected. The solutions are also compared with observations from a tower on Östergarnsholm Island in the Baltic Sea. Illustrative examples and the comparisons between observations and the theoretical predictions demonstrate that the surface waves have a considerable impact, not only on the near-surface mean wind profile, but also on the turbulence structure of the marine ABL, as they change qualitatively the structure of the ABL.

Song, Jinbao; Fan, Wei; Li, Shuang; Zhou, Ming

2015-04-01

199

Impact of Exotic Invertebrate Invaders on Food Web Structure and Function in the Great Lakes: a Network Analysis Approach  

E-print Network

Impact of Exotic Invertebrate Invaders on Food Web Structure and Function in the Great Lakes a second wave of species invasions dominated by exotic invertebrates- Zebra mussels (Dreissena polymorpha invasions (e.g., sea Lamprey and Alewife), these invertebrates inserted themselves in the lower trophic

200

Impact of Emphysema Heterogeneity on Pulmonary Function  

PubMed Central

Objectives To investigate the association between emphysema heterogeneity in spatial distribution, pulmonary function and disease severity. Methods and Materials We ascertained a dataset of anonymized Computed Tomography (CT) examinations acquired on 565 participants in a COPD study. Subjects with chronic bronchitis (CB) and/or bronchodilator response were excluded resulting in 190 cases without COPD and 160 cases with COPD. Low attenuations areas (LAAs) (?950 Hounsfield Unit (HU)) were identified and quantified at the level of individual lobes. Emphysema heterogeneity was defined in a manner that ranged in value from ?100% to 100%. The association between emphysema heterogeneity and pulmonary function measures (e.g., FEV1% predicted, RV/TLC, and DLco% predicted) adjusted for age, sex, and smoking history (pack-years) was assessed using multiple linear regression analysis. Results The majority (128/160) of the subjects with COPD had a heterogeneity greater than zero. After adjusting for age, gender, smoking history, and extent of emphysema, heterogeneity in depicted disease in upper lobe dominant cases was positively associated with pulmonary function measures, such as FEV1 Predicted (p<.001) and FEV1/FVC (p<.001), as well as disease severity (p<0.05). We found a negative association between HI% , RV/TLC (p<0.001), and DLco% (albeit not a statistically significant one, p?=?0.06) in this group of patients. Conclusion Subjects with more homogeneous distribution of emphysema and/or lower lung dominant emphysema tend to have worse pulmonary function. PMID:25409328

Gu, Suicheng; Leader, Joseph K.; Wang, Xiaohua; Chen, Yahong; Zheng, Bin; Wu, Shandong; Gur, David; Sciurba, Frank; Pu, Jiantao

2014-01-01

201

Wave propagation in graphite/epoxy laminates due to impact  

NASA Technical Reports Server (NTRS)

The low velocity impact response of graphite-epoxy laminates is investigated theoretically and experimentally. A nine-node isoparametric finite element in conjunction with an empirical contact law was used for the theoretical investigation. Flat laminates subjected to pendulum impact were used for the experimental investigation. Theoretical results are in good agreement with strain gage experimental data. The collective results of the investigation indicate that the theoretical procedure describes the impact response of the laminate up to about 150 in/sec. impact velocity.

Tan, T. M.; Sun, C. T.

1982-01-01

202

The string wave function across a Kasner singularity  

E-print Network

A collision of orbifold planes in eleven dimensions has been proposed as an explanation of the hot big bang. When the two planes are close to each other, the winding membranes become the lightest modes of the theory, and can be effectively described in terms of fundamental strings in a ten dimensional background. Near the brane collision, the eleven-dimensional metric is an Euclidean space times a 1+1-dimensional Milne universe. However, one may expect small perturbations to lead into a more general Kasner background. In this paper we extend the previous classical analysis of winding membranes to Kasner backgrounds, and using the Hamiltonian equations, solve for the wave function of loops with circular symmetry. The evolution across the singularity is regular, and explained in terms of the excitement of higher oscillation modes. We also show there is finite particle production and unitarity is preserved.

Edmund J. Copeland; Gustavo Niz; Neil Turok

2010-05-23

203

Generalized valence bond wave functions in quantum Monte Carlo  

NASA Astrophysics Data System (ADS)

We present a technique for using quantum Monte Carlo (QMC) to obtain high quality energy differences. We use generalized valence bond (GVB) wave functions, for an intuitive approach to capturing the important sources of static correlation, without needing to optimize the orbitals with QMC. Using our modifications to Walker branching and Jastrows, we can then reliably use diffusion quantum Monte Carlo to add in all the dynamic correlation. This simple approach is easily accurate to within a few tenths of a kcal/mol for a variety of problems, which we demonstrate for the adiabatic singlet-triplet splitting in methylene, the vertical and adiabatic singlet-triplet splitting in ethylene, 2+2 cycloaddition, and Be2 bond breaking.

Anderson, Amos G.; Goddard, William A.

2010-04-01

204

Correlated Electron-Nuclear Dynamics with Conditional Wave Functions  

NASA Astrophysics Data System (ADS)

The molecular Schrödinger equation is rewritten in terms of nonunitary equations of motion for the nuclei (or electrons) that depend parametrically on the configuration of an ensemble of generally defined electronic (or nuclear) trajectories. This scheme is exact and does not rely on the tracing out of degrees of freedom. Hence, the use of trajectory-based statistical techniques can be exploited to circumvent the calculation of the computationally demanding Born-Oppenheimer potential-energy surfaces and nonadiabatic coupling elements. The concept of the potential-energy surface is restored by establishing a formal connection with the exact factorization of the full wave function. This connection is used to gain insight from a simplified form of the exact propagation scheme.

Albareda, Guillermo; Appel, Heiko; Franco, Ignacio; Abedi, Ali; Rubio, Angel

2014-08-01

205

The Relation Between Equal-Time and Light-Front Wave Functions  

E-print Network

The relation between equal-time and light-front wave functions is studied using models for which the four-dimensional solution of the Bethe-Salpeter wave function can be obtained. The popular prescription of defining the longitudinal momentum fraction using the instant-form free kinetic energy and third component of momentum is found to be incorrect except in the non-relativistic limit. The only presently known way to obtain light-front wave functions from rest-frame, instant-form wave functions is to boost the latter wave functions to the infinite momentum frame. Despite this fact, we prove a relation between certain integrals of the equal-time and light-front wave functions.

Gerald A. Miller; Brian C. Tiburzi

2009-11-25

206

The study of leading twist light cone wave functions of J/Psi meson  

E-print Network

This paper is devoted to the study of leading twist light cone wave functions of J/Psi meson. The moments of these wave functions have been calculated within three approaches: potential models, nonrelativistic QCD and QCD sum rules. Using the results obtained within these approaches the models for the light cone wave functions of leading twist have been proposed. Similarly to the wave function of eta_c meson the leading twist light cone wave functions of J/Psi meson have very interesting properties at scales greater than m_c: improvement of the accuracy of the model, appearance of relativistic tail and violation of nonrelativistic QCD velocity scaling rules. The last two properties are the properties of true leading twist light cone wave functions of J/Psi meson.

V. V. Braguta

2007-01-27

207

Equality Impact Assessment Summary Name of policy, function or service  

E-print Network

Equality Impact Assessment Summary Name of policy, function or service Community Involvement with community involvement with woodlands. Who will benefit mainly from this policy, function or service? . The audiences for this Policy Position are woodland owners and managers, community groups, public, private

208

Hormonal profile impact on female sexual function in young women  

NASA Astrophysics Data System (ADS)

Female sexual function is dependent, in physiological milieu upon hormonal impulses: estradiol, testosterone, cortisol, progesterone, prolactin and TSH. Out study tries to appreciate the impact of testosterone, estradiol and prolactin, the major hormones involved in the sexual response, on the normal sexual function. This parameter is approximated by the value of the total FSFI score, a validated international structured interview.

Stoian, Dana; Craciunescu, Mihalea; Craina, Marius; Pater, Liana; Pater, Flavius

2014-12-01

209

Impact of Locally Suppressed Wave sources on helioseismic travel times  

E-print Network

Wave travel-time shifts in the vicinity of sunspots are typically interpreted as arising predominantly from magnetic fields, flows, and local changes in sound speed. We show here that the suppression of granulation related wave sources in a sunspot can also contribute significantly to these travel-time shifts, and in some cases, an asymmetry between in and outgoing wave travel times. The tight connection between the physical interpretation of travel times and source-distribution homogeneity is confirmed. Statistically significant travel-time shifts are recovered upon numerically simulating wave propagation in the presence of a localized decrease in source strength. We also demonstrate that these time shifts are relatively sensitive to the modal damping rates; thus we are only able to place bounds on the magnitude of this effect. We see a systematic reduction of 10-15 seconds in $p$-mode mean travel times at short distances ($\\sim 6.2$ Mm) that could be misinterpreted as arising from a shallow (thickness of 1.5 Mm) increase ($\\sim$ 4%) in the sound speed. At larger travel distances ($\\sim 24$ Mm) a 6-13 s difference between the ingoing and outgoing wave travel times is observed; this could mistakenly be interpreted as being caused by flows.

S. M. Hanasoge; S. Couvidat; S. P. Rajaguru; A. C. Birch

2008-03-13

210

On electron energy distribution function measurements in microwave discharges sustained by propagating surface waves  

Microsoft Academic Search

The possibility of measuring the electron energy distribution function in microwave discharges sustained by the field of propagating surface waves via a second derivative technique is demonstrated. The influence of different measuring probe orientations (axial or radial with respect to the discharge axis) on the measured electrodynamic surface wave parameters and distribution functions is examined. The electron energy distribution functions

S. Grosse; H. Schluter; E. Tatarova

1994-01-01

211

Impact detection using ultrasonic waves based on case based reasoning  

NASA Astrophysics Data System (ADS)

This study focuses on a structural health monitoring (SHM) using case-based reasoning (CBR). Structural condition is diagnosed using propagation patterns of ultra-sonic waves. Firstly, emitted pseudo-AE waves are measured in pencil lead fracture experiments. Then, the AE signals are classified into 90 types according to location, magnitude and structural condition. Secondly, pattern identification is conducted using feature parameters extracted from the signals for damage pattern recognition. Finally, feasibility of the method to real structures using CBR is studied. Results showed that the damage patterns could be determined with 82% accuracy. If only the damage location is needed, of the accuracy was higher with 95%. The proposed method using ultra-sonic waves and CBR is thus feasible for practical applications.

Otsuka, Takehisa; Mita, Akira

2008-03-01

212

Sedimentological effects of tsunamis, with particular reference to impact-generated and volcanogenic waves  

NASA Technical Reports Server (NTRS)

Impulse-generated waves (tsunamis) may be produced, at varying scales and global recurrence intervals (RI), by several processes. Meteorite-water impacts will produce tsunamis, and asteroid-scale impacts with associated mega-tsunamis may occur. A bolide-water impact would undoubtedly produce a major tsunami, whose sedimentological effects should be recognizable. Even a bolide-land impact might trigger major submarine landslides and thus tsunamis. In all posulated scenarios for the K/T boundary event, then, tsunamis are expected, and where to look for them must be determined, and how to distinguish deposits from different tsunamis. Also, because tsunamis decrease in height as they move away from their source, the proximal effects will differ by perhaps orders of magnitude from distal effects. Data on the characteristics of tsunamis at their origin are scarce. Some observations exist for tsunamis generated by thermonuclear explosions and for seismogenic tsunamis, and experimental work was conducted on impact-generated tsunamis. All tsunamis of interest have wave-lengths of 0(100) km and thus behave as shallow-water waves in all ocean depths. Typical wave periods are 0(10 to 100) minutes. The effect of these tsunamis can be estimated in the marine and coastal realm by calculating boundary shear stresses (expressed as U*, the shear velocity). An event layer at the K/T boundary in Texas occurs in mid-shelf muds. Only a large, long-period wave with a wave height of 0(50) m, is deemed sufficient to have produced this layer. Such wave heights imply a nearby volcanic explosion on the scale of Krakatau or larger, or a nearby submarine landslide also of great size, or a bolide-water impact in the ocean.

Bourgeois, Joanne; Wiberg, Patricia L.

1988-01-01

213

Pion light cone wave function in the non-local NJL model  

E-print Network

We use the simple instanton motivated NJL-type model to calculate the leading twist pion light cone wave function. The model consists in employing the momentum dependent quark mass in the quark loop entering the definition of the wave function. The result is analytical up to a solution of a certain algebraic equation. Various properties including the kT dependence of the pion wave function are discussed. The resulting kT integrated wave function is not asymptotic and is in agreement with recent analysis of the CLEO data.

M. Praszalowicz; A. Rostworowski

2001-08-29

214

Pion and photon light-cone wave functions from the instanton vacuum  

E-print Network

The leading-twist wave functions of the pion and the photon at a low normalization point are calculated in the effective low--energy theory derived from the instanton vacuum. The pion wave function is found to be close to the asymptotic one, consistent with the recent CLEO measurements. The photon wave function is non-zero at the endpoints. This different behavior is a consequence of the momentum dependence of the dynamical quark mass suggested by the instanton vacuum. We comment on the relation of meson wave functions and off-forward parton distributions in this model.

V. Yu. Petrov; M. V. Polyakov; R. Ruskov; C. Weiss; K. Goeke

1998-07-02

215

Optical path function calculation for an incoming cylindrical wave  

NASA Astrophysics Data System (ADS)

Modern polishing methods of ion-beam milling, and single atom removal techniques are beginning to allow the fabrication of arbitrary surface shapes for reflecting grazing incidence optics. Moreover, the total expense of fabrication, coating, measuring, mounting, aligning, cooling, and surrounding the optic with vacuum make the reduction of optical part count attractive for the latest generation x-ray sources, not even considering potential effects on the scattering and reflective losses of the radiation. These two developments converge to effectively suggest the question of what surface would be the optimally de-magnifying surface to replace a toroid illuminated by a wave cylindrical in the sagittal direction if the sag of the single surface were determined by a function, and not constrained to be a typical optical shape. To address this we derive a simplified case of the formalism of Chrisp, using the classical optical path function approach of Fermat to give a power series calculation of this best surface. This surface, the "diaboloid," would in principle earn its name by its, at least ab initio, consideration of being very difficult to manufacture. We show an example of improvement this surface would provide.

McKinney, Wayne R.; Glossinger, James M.; Padmore, Howard A.; Howells, Malcolm R.

2009-08-01

216

Propagating two-particle reduced density matrices without wave functions  

NASA Astrophysics Data System (ADS)

Describing time-dependent many-body systems where correlation effects play an important role remains a major theoretical challenge. In this paper we develop a time-dependent many-body theory that is based on the two-particle reduced density matrix (2-RDM). We present a closed equation of motion for the 2-RDM by developing a reconstruction functional for the three-particle reduced density matrix (3-RDM) that preserves norm, energy, and spin symmetries during time propagation. We show that approximately enforcing N -representability during time evolution is essential for achieving stable solutions. As a prototypical test case which features long-range Coulomb interactions we employ the one-dimensional model for lithium hydride (LiH) in strong infrared laser fields. We probe both one-particle observables such as the time-dependent dipole moment and two-particle observables such as the pair density and mean electron-electron interaction energy. Our results are in very good agreement with numerically exact solutions for the N -electron wave function obtained from the multiconfigurational time-dependent Hartree-Fock method.

Lackner, Fabian; B?ezinová, Iva; Sato, Takeshi; Ishikawa, Kenichi L.; Burgdörfer, Joachim

2015-02-01

217

Riemann {zeta} function from wave-packet dynamics  

SciTech Connect

We show that the time evolution of a thermal phase state of an anharmonic oscillator with logarithmic energy spectrum is intimately connected to the generalized Riemann {zeta} function {zeta}(s,a). Indeed, the autocorrelation function at a time t is determined by {zeta}({sigma}+i{tau},a), where {sigma} is governed by the temperature of the thermal phase state and {tau} is proportional to t. We use the JWKB method to solve the inverse spectral problem for a general logarithmic energy spectrum; that is, we determine a family of potentials giving rise to such a spectrum. For large distances, all potentials display a universal behavior; they take the shape of a logarithm. However, their form close to the origin depends on the value of the Hurwitz parameter a in {zeta}(s,a). In particular, we establish a connection between the value of the potential energy at its minimum, the Hurwitz parameter and the Maslov index of JWKB. We compare and contrast exact and approximate eigenvalues of purely logarithmic potentials. Moreover, we use a numerical method to find a potential which leads to exact logarithmic eigenvalues. We discuss possible realizations of Riemann {zeta} wave-packet dynamics using cold atoms in appropriately tailored light fields.

Mack, R.; Schleich, W. P. [Institut fuer Quantenphysik, Albert-Einstein-Allee 11, Universitaet Ulm, D-89069 Ulm (Germany); Dahl, J. P. [Institut fuer Quantenphysik, Albert-Einstein-Allee 11, Universitaet Ulm, D-89069 Ulm (Germany); Chemical Physics, Department of Chemistry, Technical University of Denmark, DTU 207, DK-2800 Kgs. Lyngby (Denmark); Moya-Cessa, H. [Institut fuer Quantenphysik, Albert-Einstein-Allee 11, Universitaet Ulm, D-89069 Ulm (Germany); Instituto Nacional de Astrofisica, Optica y Electronica, Apartado Postal 51 Y 216, 72000 Puebla (Mexico); Strunz, W. T. [Institut fuer Theoretische Physik, Technische Universitaet Dresden, D-01062 Dresden (Germany); Walser, R. [Institut fuer Quantenphysik, Albert-Einstein-Allee 11, Universitaet Ulm, D-89069 Ulm (Germany); Institut fuer Angewandte Physik, Technische Universitaet Darmstadt, D-64289 Darmstadt (Germany)

2010-09-15

218

The impact of density heterogeneities on seismic wave propagation  

NASA Astrophysics Data System (ADS)

Using 3D numerical simulations of seismic wave propagation in heterogeneous media, we systematically compare the imprints of heterogeneities of different type (and particularly density heterogeneities) on synthetic seismograms. Lateral density variations are the source of mass transport in the Earth at all scales, acting as drivers of convective motion in the mantle. However, the density structure of the Earth remains largely unknown since classic seismic observables and gravity provide only weak constraints with strong trade-offs. Current density models are therefore often based on velocity scaling, making strong assumptions on the origin of structural heterogeneities, which may not necessarily be true. We propose to develop a seismic tomography technique that directly inverts for density, using complete seismograms rather than arrival times of certain waves only. The first task in this challenge is to systematically study the imprints of density on synthetic seismograms. In this context, our study aims to compare the significance of density heterogeneities relative to velocity heterogeneities, and to design a numerical experiment with a source-receiver configuration particularly sensitive to density. To compute the full seismic wavefield in a 3D heterogeneous medium without making significant approximations, we use numerical wave propagation based on a spectral-element discretization of the seismic wave equation. We consider a 2000 by 1000 km wide and 500 km deep spherical section, with the 1D Earth model ak135 as a background. Onto this we superimpose 3D Gaussian-shaped perturbations of different type (P, SV, SH velocities and density) for depths in the range from 10 km to 70 km. The choice of depth in which the 3D heterogeneities were placed (10 km - 70 km) was dictated by the surface wave sensitivity to density. For each depth we perform 4 wave propagation simulations corresponding to 4 different types of heterogeneities, and calculate surface wave sensitivity kernels. We compare the synthetic seismograms for different types of heterogeneities with seismograms for the 1D reference model, using various misfit criteria, including weighted envelope and phase differences based on continuous wavelet transforms. Our preliminary analyses indicate that density variations do leave a noticeable mark on seismograms, which is of the same order of magnitude as the one from velocity variations. This suggests that the solution of the seismic inverse problem for density may become feasible.

P?onka, Agnieszka; Fichtner, Andreas

2014-05-01

219

Elastic coefficients of aluminum as functions of the degree of compression in a shock wave  

Microsoft Academic Search

The velocities of elastic relief waves in commercial aluminum (AD1) and aluminum alloy (D16) samples compressed by a shock wave were measured by the most direct method. Using these results together with the relationship for the three-dimensional velocity of sound as a function of the intensity of the sound wave (derived on the assumption that the shock adiabat and the

A. A. Vorob'ev; A. N. Dremin; G. I. Kanel

1974-01-01

220

Impact of complex blast waves on the human head: a computational study.  

PubMed

Head injuries due to complex blasts are not well examined because of limited published articles on the subject. Previous studies have analyzed head injuries due to impact from a single planar blast wave. Complex or concomitant blasts refer to impacts usually caused by more than a single blast source, whereby the blast waves may impact the head simultaneously or consecutively, depending on the locations and distances of the blast sources from the subject, their blast intensities, the sequence of detonations, as well as the effect of blast wave reflections from rigid walls. It is expected that such scenarios will result in more serious head injuries as compared to impact from a single blast wave due to the larger effective duration of the blast. In this paper, the utilization of a head-helmet model for blast impact analyses in Abaqus(TM) (Dassault Systemes, Singapore) is demonstrated. The model is validated against studies published in the literature. Results show that the skull is capable of transmitting the blast impact to cause high intracranial pressures (ICPs). In addition, the pressure wave from a frontal blast may enter through the sides of the helmet and wrap around the head to result in a second impact at the rear. This study recommended better protection at the sides and rear of the helmet through the use of foam pads so as to reduce wave entry into the helmet. The consecutive frontal blasts scenario resulted in higher ICPs compared with impact from a single frontal blast. This implied that blast impingement from an immediate subsequent pressure wave would increase severity of brain injury. For the unhelmeted head case, a peak ICP of 330?kPa is registered at the parietal lobe which exceeds the 235?kPa threshold for serious head injuries. The concurrent front and side blasts scenario yielded lower ICPs and skull stresses than the consecutive frontal blasts case. It is also revealed that the additional side blast would only significantly affect ICPs at the temporal and parietal lobes when compared with results from the single frontal blast case. By analyzing the pressure wave flow surrounding the head and correlating them with the consequential evolution of ICP and skull stress, the paper provides insights into the interaction mechanics between the concomitant blast waves and the biological head model. PMID:25132676

Tan, Long Bin; Chew, Fatt Siong; Tse, Kwong Ming; Chye Tan, Vincent Beng; Lee, Heow Pueh

2014-12-01

221

Impact of ozone depletion on immune function  

SciTech Connect

Depletion of stratospheric ozone is expected to lead to an increase in the amount of UV-B radiation present in sunlight. In addition to its well known ability to cause skin cancer, UV-B radiation has been shown to alter the immune system. The immune system is the body's primary defense mechanism against infectious diseases and protects against the development of certain types of cancer. Any impairment of immune function may jeopardize health by increasing susceptibility to infectious diseases, increasing the severity of infections, or delaying recovery for infections. In addition, impaired immune function can increase the incidence of certain cancers, particularly cancers of the skin. Research carried out with laboratory animals over the past 15 years has demonstrated that exposure of the skin to UV-B radiation can suppress certain types of immune responses. These include rejection of UV-induced skin cancers and melanomas, contact allergy reactions to chemicals, delayed-type hypersensitivity responses to microbial and other antigens, and phagocytosis and elimination of certain bacteria from lymphoid tissues. Recent studies with mycobacterial infection of mice demonstrated that exposure to UV-B radiation decreased the delayed hypersensitivity response to mycobacterial antigens and increased the severity of infection. In humans, UV-B radiation has also been shown to impair the contact allergy response. These studies demonstrate that UV radiation can decrease immune responses in humans and laboratory and raise the possibility that increased exposure to UV-B radiation could adversely affect human health by increasing the incidence or severity of certain infectious diseases.

Jeevan, A.; Kripke, M.L. (Univ. of Texas, Houston, TX (United States). Dept. of Immunology)

1993-06-01

222

Quantization causes waves:Smooth finitely computable functions are affine  

E-print Network

Given an automaton (a letter-to-letter transducer, a dynamical 1-Lipschitz system on the space $\\mathbb Z_p$ of $p$-adic integers) $\\mathfrak A$ whose input and output alphabets are $\\mathbb F_p=\\{0,1,\\ldots,p-1\\}$, one visualizes word transformations performed by $\\mathfrak A$ by a point set $\\mathbf P(\\mathfrak A)$ in real plane $\\mathbb R^2$. For a finite-state automaton $\\mathfrak A$, it is shown that once some points of $\\mathbf P(\\mathfrak A)$ constitute a smooth (of a class $C^2$) curve in $\\mathbb R^2$, the curve is a segment of a straight line with a rational slope; and there are only finitely many straight lines whose segments are in $\\mathbf{P}(\\mathfrak A)$. Moreover, when identifying $\\mathbf P(\\mathfrak A)$ with a subset of a 2-dimensional torus $\\mathbb T^2\\subset\\mathbb R^3$ (under a natural mapping of the real unit square $[0,1]^2$ onto $\\mathbb T^2$) the smooth curves from $\\mathbf P(\\mathfrak A)$ constitute a collection of torus windings. In cylindrical coordinates either of the windings can be ascribed to a complex-valued function $\\psi(x)=e^{i(Ax-2\\pi B(t))}$ $(x\\in\\mathbb R)$ for suitable rational $A,B(t)$. Since $\\psi(x)$ is a standard expression for a matter wave in quantum theory (where $B(t)=tB(t_0)$), and since transducers can be regarded as a mathematical formalization for causal discrete systems, the paper might serve as a mathematical reasoning why wave phenomena are inherent in quantum systems: This is because of causality principle and the discreteness of matter.

Vladimir Anashin

2015-02-06

223

Impact of weightlessness on muscle function  

NASA Technical Reports Server (NTRS)

The most studied skeletal muscles which depend on gravity, "antigravity" muscles, are located in the posterior portion of the legs. Antigravity muscles are characterized generally by a different fiber type composition than those which are considered nonpostural. The gravity-dependent function of the antigravity muscles makes them particularly sensitive to weightlessness (unweighting) resulting in a substantial loss of muscle protein, with a relatively greater loss of myofibrillar (structural) proteins. Accordingly alpha-actin mRNA decreases in muscle of rats exposed to microgravity. In the legs, the soleus seems particularly responsive to the lack of weight-bearing associated with space flight. The loss of muscle protein leads to a decreased cross-sectional area of muscle fibers, particularly of the slow-twitch, oxidative (SO) ones compared to fast-twitch glycolytic (FG) or oxidative-glycolytic (FOG) fibers. In some muscles, a shift in fiber composition from SO to FOG has been reported in the adaptation to spaceflight. Changes in muscle composition with spaceflight have been associated with decreased maximal isometric tension (Po) and increased maximal shortening velocity. In terms of fuel metabolism, results varied depending on the pathway considered. Glucose uptake, in the presence of insulin, and activities of glycolytic enzymes are increased by space flight. In contrast, oxidation of fatty acids may be diminished. Oxidation of pyruvate, activity of the citric acid cycle, and ketone metabolism in muscle seem to be unaffected by microgravity.

Tischler, M. E.; Slentz, M.

1995-01-01

224

Using soil functional indices to assess wildfire impact  

NASA Astrophysics Data System (ADS)

Disturbance impact on ecosystem are often based on functional indicators, which provide integrated and yet simple and affordable measures of key ecosystem functions. In this work, we studied the amount of change (resistance) and the recovery (resilience) of soil functions after fire as a function of vegetation type for a variety of Mediterranean shrublands. We used the Landscape Functional Analysis methodology to assess soil stability, water infiltration, and nutrient cycling functions for different types of vegetation patches and for bare-soil interpatches in repeatedly burned shrubland communities two weeks before, and two and nine months after experimental fires. We assessed the impact of fire on soil functions using resistance and resilience indices. The resistance and resilience of soil surface functions to fire was mediated by vegetation traits associated to the fuel structure and the post-fire regenerative strategy of the species. Resistance was higher in vegetation patches that accumulated low contents of fine dead fuel, whereas resilience was higher in patches of resprouter species. The variation in resistance and resilience of soil functions to fire in Mediterranean shrublands depends greatly on variation in fire-related plant structural and functional traits. Although originally designed for the assessment of dryland ecosystems LFA has proved to have great potential for the assessment of the soil functional status of recently burned areas.

López-Poma, Rosario; Mayor, Ángeles G.; Bautista, Susana

2014-05-01

225

Waves  

NSDL National Science Digital Library

We will review some basic properties of waves and then further explore sound and light. For a quick overview of some properties of all waves, click on this first site. Make sure you fill out your hand out as you work! Waves and Wave Motion : Describing Waves Practice what you've already learned about waves with this site: Waves This site will let you play around some more with transverse waves: Wave on a String Sound waves are mechanical waves, ...

Mrs. Petersen

2014-05-27

226

Functional Adult Literacy and Empowerment of Women: Impact of a Functional Literacy Program in Turkey  

ERIC Educational Resources Information Center

This study addresses the impact of functional adult literacy on the empowerment of women in the absence of formal schooling. It examines whether the effects of functional literacy are exclusively content specific or whether there are gains going beyond the obvious benefits and extending to other spheres of everyday functioning, such as…

Kagitcibasi, Cigdem; Goksen, Fatos; Gulgoz, Sami

2005-01-01

227

Impact of cosmic neutrinos on the gravitational-wave background  

SciTech Connect

We obtain the equation governing the evolution of the cosmological gravitational-wave background, accounting for the presence of cosmic neutrinos, up to second order in perturbation theory. In particular, we focus on the epoch during radiation dominance, after neutrino decoupling, when neutrinos yield a relevant contribution to the total energy density and behave as collisionless ultrarelativistic particles. Besides recovering the standard damping effect due to neutrinos, a new source term for gravitational waves is shown to arise from the neutrino anisotropic stress tensor. The importance of such a source term, so far completely disregarded in the literature, is related to the high velocity dispersion of neutrinos in the considered epoch; its computation requires solving the full second-order Boltzmann equation for collisionless neutrinos.

Mangilli, Anna; Bartolo, Nicola; Matarrese, Sabino; Riotto, Antonio [Institute of Space Sciences (CSIC-IEEC) Campus UAB, Torre C5 parell 2. Bellaterra (Barcelona) (Spain); Dipartimento di Fisica 'Galileo Galilei', Universita di Padova, via Marzolo 8, I-35131 Padova (Italy); Dipartimento di Fisica 'Galileo Galilei', Universita di Padova (Italy); INFN, Sezione di Padova, via Marzolo 8, I-35131 Padova (Italy); INFN, Sezione di Padova, via Marzolo 8, I-35131 Padova (Italy); CERN, Theory Division, CH-1211 Geneva 23 (Switzerland)

2008-10-15

228

Health Impact of the 2003 Heat-Wave in France  

Microsoft Academic Search

An unprecedented heat-wave struck France in early August 2003, associated to high levels of air pollution. The meteorological\\u000a event was accompanied by an excess of mortality that started early and rose quickly. Between August 1st and 20th, the excess\\u000a of deaths reached 14,802 cases in comparison to the average daily mortality in the 2000 – 2002 period. It represents +60

Stéphanie Vandentorren; Pascal Empereur-Bissonnet

229

Impact of Urban Expansion on Summer Heat Wave in Beijing  

Microsoft Academic Search

There is increasing evidence that rapid urbanization in China has intensified summer heat wave in recent decades in the background of global warming. This study implements two land-cover classification from the U.S. Geological Survey (USGS) and the Moderate Resolution Imaging Spectroradiometer (MODIS) in the Weather Research and Forecast model (WRF), version 2.2, and investigates the regional effect of urban expansion

Hongyun Ma; Jie Song; Pinwen Guo

2009-01-01

230

Impact of attenuator models on computed traveling wave tube performances  

NASA Astrophysics Data System (ADS)

Radio frequency characteristics of helix traveling wave tubes are analyzed with a one-dimensional numerical model that includes a new, more rigorous, self-consistent attenuator model. The nonlinear properties of the beam-wave interaction, including gain, phase distortion, and intermodulation distortion, are analyzed and compared with simulations using a conventional one-dimensional model of the attenuator. The comparative results show that the small signal gain is about 2-5dB smaller with the new model than with the conventional and wave phase has a difference of 2°-6° between the new and conventional models in the intermediate and large signal regions. The amplitude modulation/phase modulation (AM/PM) conversion from the new model shows a slower reach to maximum than that from the conventional, and when the large input signal is applied, the conventional model's AM/PM conversion oscillates more quickly compared to the new. Under two-frequency excitation, the fundamental tones are about 5-7dB smaller with the new model than the conventional, while the intermodulation products are approximately 10dB smaller relative to the conventional model.

Duan, Zhaoyun; Gong, Yubin; Wei, Yanyu; Wang, Wenxiang

2007-09-01

231

Systematic theoretical investigation of the zero-field splitting in Gd(III) complexes: wave function and density functional approaches.  

PubMed

The zero-field splitting (ZFS) of the electronic ground state in paramagnetic ions is a sensitive probe of the variations in the electronic and molecular structure with an impact on fields ranging from fundamental physical chemistry to medical applications. A detailed analysis of the ZFS in a series of symmetric Gd(III) complexes is presented in order to establish the applicability and accuracy of computational methods using multiconfigurational complete-active-space self-consistent field wave functions and of density functional theory calculations. The various computational schemes are then applied to larger complexes Gd(III)DOTA(H2O)(-), Gd(III)DTPA(H2O)(2-), and Gd(III)(H2O)8(3+) in order to analyze how the theoretical results compare to experimentally derived parameters. In contrast to approximations based on density functional theory, the multiconfigurational methods produce results for the ZFS of Gd(III) complexes on the correct order of magnitude. PMID:25612706

Khan, Shehryar; Kubica-Misztal, Aleksandra; Kruk, Danuta; Kowalewski, Jozef; Odelius, Michael

2015-01-21

232

Covariant nucleon wave function with S, D, and P-state components  

SciTech Connect

Expressions for the nucleon wave functions in the covariant spectator theory (CST) are derived. The nucleon is described as a system with a off-mass-shell constituent quark, free to interact with an external probe, and two spectator constituent quarks on their mass shell. Integrating over the internal momentum of the on-mass-shell quark pair allows us to derive an effective nucleon wave function that can be written only in terms of the quark and diquark (quark-pair) variables. The derived nucleon wave function includes contributions from S, P and D-waves.

Franz Gross, G. Ramalho, M. T. Pena

2012-05-01

233

Failure Wave in DEDF and Soda-Lime Glass during Rod Impact  

SciTech Connect

Investigations of glass by planar, and classical and symmetric Taylor impact experiments reveal that failure wave velocity vF depends on impact velocity, geometry, and type of glass. vF typically increases with impact velocity vP to between cS and cL or to {radical}2cS (shear and longitudinal wave velocity). This paper reports initial results of an investigation of failure waves associated with gold rod impact on high-density (DEDF) glass and soda-lime glass. Data are obtained by visualizing simultaneously the failure propagation in the glass with a high-speed camera and the rod penetration velocity u with flash radiography. Results for DEDF glass are reported for vP between 1.2 and 2.0 km/s, those for soda-lime glass with vP {approx_equal}1.3 km/s. It is shown that vF > u, and that in the case of DEDF glass vF/u decreases from ; 1.38 to 1.13 with increasing vp. In addition, several Taylor tests were performed. For both DEDF and soda-lime glass the vF-values, found here as well as vF- data reported in the literature, reveal that--for equal pressures--the failure wave velocities determined from Taylor tests or planar-impact tests are distinctly greater than those observed during steady-state rod penetration.

Orphal, D. L. [International Research Associates, Inc., 4450 Black Avenue, Pleasanton, CA 94566 (United States); Behner, Th.; Hohler, V. [Fraunhofer Institut fuer Kurzzeitdynamik (Ernst-Mach Institut), Eckerstr. 4, 79104 Freiburg (Germany); Anderson, C. E. Jr. [Southwest Research Institute, 6220 Culebra Road, San Antonio, TX 78228-0510 (United States); Templeton, D. W. [U. S. Army RDECOM-TACOM, AMST-TR-R, Warren, MI 48397 (United States)

2006-07-28

234

A dynamical model for longitudinal wave functions in light-front holographic QCD  

E-print Network

We construct a Schrodinger-like equation for the longitudinal wave function of a meson in the valence qq-bar sector, based on the 't Hooft model for large-N two-dimensional QCD, and combine this with the usual transverse equation from light-front holographic QCD, to obtain a model for mesons with massive quarks. The computed wave functions are compared with the wave function ansatz of Brodsky and De Teramond and used to compute decay constants and parton distribution functions. The basis functions used to solve the longitudinal equation may be useful for more general calculations of meson states in QCD.

S. S. Chabysheva; J. R. Hiller

2013-07-14

235

Impact of a Convectively Forced Gravity Wave Drag Parameterization in NCAR CCM3.  

NASA Astrophysics Data System (ADS)

A parameterization of gravity wave drag forced by subgrid-scale cumulus convection (GWDC) proposed by Chun and Baik is implemented into the National Center for Atmospheric Research Community Climate Model (NCAR CCM3) and its effect on perpetual January and July climate is investigated. The cloud-top gravity wave stress is concentrated in the intertropical convergence zone where persistent deep cumulus clouds exist. The resultant zonal wind acceleration due to the breaking of convectively forced gravity waves is predominantly found in the tropical lower stratosphere with westerly acceleration above cloud top and easterly acceleration just below it. Since the parameterized gravity waves are stationary relative to convective clouds, wave breaking occurs mainly in the tropical lower stratosphere where the zonal wind is weak enough for wave saturation. It is shown that the GWDC parameterization significantly alleviates the systematic model biases of zonal-mean zonal wind and temperature. In particular, excessive easterlies in the tropical stratosphere and excessive cold temperatures in the tropical lower stratosphere are reduced by more than 50% by including the GWDC parameterization. The horizontal wind divergence field in the tropical upper troposphere and lower stratosphere is also significantly improved with the GWDC parameterization.The impact of the GWDC parameterization extends to mid- to high latitudes through planetary wave activity in the winter hemisphere. The increased amplitude of zonal wavenumber 3 in the January Northern Hemisphere and the increased amplitude of zonal wavenumber 2 in the July Southern Hemisphere lead to significant improvements in model performance. The impact of the GWDC parameterization on Eliassen Palm (EP) flux divergence forcing by stationary waves is generally opposite to that by transient waves in the extratropics, especially in the Northern Hemisphere wintertime. Hence, the zonal-mean zonal wind change by the GWDC parameterization occurs mainly in the Tropics by direct gravity wave drag forcing.


Chun, Hye-Yeong; Song, In-Sun; Baik, Jong-Jin; Kim, Young-Joon

2004-09-01

236

Theoretical and Experimental Evidences of Material Phase Causality. Dynamics-Statistical Interpretation of the Wave Function  

E-print Network

The internal phase dynamics of a quantum system is revealed in details. Theoretical and experimental evidences of existence of a causal relation of the phase of the wave function with the dynamics of the quantum system are presented sistematically for the first time. A new, dynamics-statistical interpretation of the quantum mechanics is introduced. A particle-wave duality picture incorporated in the wave function through its phase and amplitude is considered.

I. G. Koprinkov

2010-04-19

237

Hadronic spectra and light-front wave functions in holographic QCD.  

PubMed

We show how the string amplitude phi(z) defined on the fifth dimension in AdS5 space can be precisely mapped to the light-front wave functions of hadrons in physical space-time. We find an exact correspondence between the holographic variable z and an impact variable zeta, which represents the measure of transverse separation of the constituents within the hadrons. In addition, we derive effective four dimensional Schrödinger equations for the bound states of massless quarks and gluons which exactly reproduce the anti-de Sitter conformal field theory results and give a realistic description of the light-quark meson and baryon spectrum as well as the form factors for space-like Q2. Only one parameter which sets the mass scale, lambda(QCD), is introduced. PMID:16803163

Brodsky, Stanley J; de Téramond, Guy F

2006-05-26

238

Hadronic Spectra and Light-Front Wave Functions in Holographic QCD  

SciTech Connect

We show how the string amplitude {phi}(z) defined on the fifth dimension in AdS{sub 5} space can be precisely mapped to the light-front wave functions of hadrons in physical space-time. We find an exact correspondence between the holographic variable z and an impact variable {zeta}, which represents the measure of transverse separation of the constituents within the hadrons. In addition, we derive effective four dimensional Schroedinger equations for the bound states of massless quarks and gluons which exactly reproduce the anti-de Sitter conformal field theory results and give a realistic description of the light-quark meson and baryon spectrum as well as the form factors for spacelike Q{sup 2}. Only one parameter which sets the mass scale, {lambda}{sub QCD}, is introduced.

Brodsky, Stanley J. [Stanford Linear Accelerator Center, Stanford University, Stanford, California 94309 (United States); Teramond, Guy F. de [Universidad de Costa Rica, San Jose (Costa Rica)

2006-05-26

239

Hadronic Spectra and Light-Front Wave Functions in Holographic QCD  

NASA Astrophysics Data System (ADS)

We show how the string amplitude ?(z) defined on the fifth dimension in AdS5 space can be precisely mapped to the light-front wave functions of hadrons in physical space-time. We find an exact correspondence between the holographic variable z and an impact variable ?, which represents the measure of transverse separation of the constituents within the hadrons. In addition, we derive effective four dimensional Schrödinger equations for the bound states of massless quarks and gluons which exactly reproduce the anti de Sitter conformal field theory results and give a realistic description of the light-quark meson and baryon spectrum as well as the form factors for spacelike Q2. Only one parameter which sets the mass scale, ?QCD, is introduced.

Brodsky, Stanley J.; de Téramond, Guy F.

2006-05-01

240

Modelling of tsunami-like wave run-up, breaking and impact on a vertical wall by SPH method  

NASA Astrophysics Data System (ADS)

Accurate predictions of wave run-up and run-down are important for coastal impact assessment of relatively long waves such as tsunami or storm waves. Wave run-up is, however, a complex process involving nonlinear build-up of the wave front, intensive wave breaking and strong turbulent flow, making the numerical approximation challenging. Recent advanced modelling methodologies could help to overcome these numerical challenges. For a demonstration, we study run-up of non-breaking and breaking solitary waves on a vertical wall using two methods, an enhanced smoothed particle hydrodynamics (SPH) method and the traditional non-breaking nonlinear model Tunami-N2. The Tunami-N2 model fails to capture the evolution of steep waves at the proximity of breaking that was observed in the experiments. Whereas the SPH method successfully simulates the wave propagation, breaking, impact on structure and the reform and breaking processes of wave run-down. The study also indicates that inadequate approximation of the wave breaking could lead to significant under-predictions of wave height and impact pressure on structures. The SPH model shows potential applications for accurate impact assessments of wave run-up on to coastal structures.

Dao, M. H.; Xu, H.; Chan, E. S.; Tkalich, P.

2013-12-01

241

Lithospheric structure beneath Eastern Africa from joint inversion of receiver functions and Rayleigh wave velocities  

NASA Astrophysics Data System (ADS)

Crust and upper mantle structure beneath eastern Africa has been investigated using receiver functions and surface wave dispersion measurements to understand the impact of the hotspot tectonism found there on the lithospheric structure of the region. In the first part of this thesis, I applied H-kappa stacking of receiver functions, and a joint inversion of receiver functions and Rayleigh wave group velocities to determine the crustal parameters under Djibouti. The two methods give consistent results. The crust beneath the GEOSCOPE station ATD has a thickness of 23+/-1.5 km and a Poisson's ratio of 0.31+/-0.02. Previous studies give crustal thickness beneath Djibouti to be between 8 and 10 km. I found it necessary to reinterprete refraction profiles for Djibouti from a previous study. The crustal structure obtained for ATD is similar to adjacent crustal structure in many other parts of central and eastern Afar. The high Poisson's ratio and Vp throughout most of the crust indicate a mafic composition, suggesting that the crust in Afar consists predominantly of new igneous rock emplaced during the late synrift stage where extension is accommodated within magmatic segments by diking. In the second part of this thesis, the seismic velocity structure of the crust and upper mantle beneath Ethiopia and Djibouti has been investigated by jointly inverting receiver functions and Rayleigh wave group velocities to obtain new constraints on the thermal structure of the lithosphere. Crustal structure from the joint inversion for Ethiopia and Djibouti is similar to previously published models. Beneath the Main Ethiopian Rift (MER) and Afar, the lithospheric mantle has a maximum shear wave velocity of 4.1-4.2 km/s and extends to a depth of at most 50 km. In comparison to the lithosphere away from the East African Rift System in Tanzania, where the lid extends to depths of ˜100-125 km and has a maximum shear velocity of 4.6 km/s, the mantle lithosphere under the Ethiopian Plateau appears to have been thinned by ˜30-50 km and the maximum shear wave velocity reduced by ˜0.3 km/s. Results from a 1D conductive thermal model suggest that the shear velocity structure of the lithosphere beneath the Ethiopian Plateau can be explained by a plume model, if a plume rapidly thinned the lithosphere by ˜30--50 km at the time of the flood basalt volcanism (c. 30 Ma), and if warm plume material has remained beneath the lithosphere since then. About 45-65% of the 1-1.5 km of plateau uplift in Ethiopia can be attributed to the thermally perturbed lithospheric structure. In the final part of this thesis, the shear-wave velocity structure of the crust and upper mantle beneath Kenya has been obtained from a joint inversion of receiver functions, and Rayleigh wave group and phase velocities. The crustal structure from the joint inversion is consistent with crustal structure published previously by different authors. The lithospheric mantle beneath the East African Plateau in Kenya is similar to the lithosphere under the East African Plateau in Tanzania. Beneath the Kenya Rift, the lithosphere extends to a depth of at most ˜75 km. The lithosphere under the Kenya Plateau is not perturbed when compared to the highly perturbed lithosphere beneath the Ethiopian Plateau. On the other hand, the lithosphere under the Kenya Rift is perturbed as compared to the Kenya Plateau or the rest of the East African Plateau, but is not as perturbed as the lithosphere beneath the Main Ethiopian Rift or the Afar. Although Kenya and Ethiopia have similar uplift and rifting histories, they have different volcanic histories. Much of Ethiopia has been affected by the Afar Flood Basalt volcanism, which may be the cause of this difference in lithospheric structure between these two regions.

Dugda, Mulugeta Tuji

242

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

E-print Network

In this article we discuss the problem of finding an interpretation of quantum mechanics which provides an objective account of physical reality. In the first place we discuss the problem of interpretation and analyze the importance of such an objective account in physics. In this context we present the problems which arise when interpreting the quantum wave function within the orthodox formulation of quantum mechanics. In connection to this critic, we expose the concept of 'entity' as an epistemological obstruction. In the second part of this paper we discuss the relation between actuality and potentiality in classical and quantum physics, and continue to present the concept of 'ontological potentiality' which is distinguished from the generic Aristotelian notion of potentiality in terms of 'becoming actual'. In this paper our main aim is to provide an objective interpretation of quantum mechanics which allows us to discuss the meaning of physical reality according to the theory. For this specific propose we present the concept of 'faculty' in place of the concept of 'entity'. Within our theory of faculties, we continue to discuss and interpret two paradigmatic experiments of quantum mechanics such as the double-slit and Schrodinger's cat.

Christian de Ronde

2007-11-29

243

Experimental determination of wave function spread in Si inversion layers  

NASA Astrophysics Data System (ADS)

We have experimentally determined the extent of wave function spread TQM in Si inversion layers on (100)-oriented surface in metal-oxide-semiconductor field-effect transistors (MOSFETs) using the back gate bias sensitivity of front gate threshold voltage of planar fully depleted silicon-on-insulator (SOI) MOSFETs. We show that the sum of TQM for large positive and negative F is an electrically determined value of the SOI thickness TSI. We find that the electric field dependence of TQM for electrons and holes is given by TQM˜F-0.4 and F-0.6, respectively, at high electric fields with TQM being larger for holes at a given F. Larger TQM for holes can be explained by the fact that holes have a smaller effective mass along the confinement direction than electrons in (100) Si. The field dependences of TQM are, however, not consistent with the results of variational calculations that assume single-subband occupancy and predict TQM˜F-1/3. The discrepancy likely indicates that the effects of multiple-subband occupation are significant at room temperature, especially for holes.

Majumdar, Amlan

2010-08-01

244

Quantum anti-Zeno effect without wave function reduction  

PubMed Central

We study the measurement-induced enhancement of the spontaneous decay for a two-level subsystem, where measurements are treated as couplings between the excited state and an auxiliary state rather than the von Neumann's wave function reduction. The photon radiated in a fast decay of the atom, from the auxiliary state to the excited state, triggers a quasi-measurement, as opposed to a projection measurement. Our use of the term “quasi-measurement” refers to a “coupling-based measurement”. Such frequent quasi-measurements result in an exponential decay of the survival probability of atomic initial state with a photon emission following each quasi-measurement. Our calculations show that the effective decay rate is of the same form as the one based on projection measurements. The survival probability of the atomic initial state obtained by tracing over all the photon states is equivalent to that of the atomic initial state with a photon emission following each quasi-measurement.

Ai, Qing; Xu, Dazhi; Yi, Su; Kofman, A. G.; Sun, C. P.; Nori, Franco

2013-01-01

245

Stress Tensor for Quantized Random Field and Wave Function Collapse  

E-print Network

The continuous spontaneous localization (CSL) theory of dynamical wave function collapse is an experimentally testable alternative to non-relativistic quantum mechanics. In it, collapse occurs because particles interact with a classical random field. However, particles gain energy from this field, i.e., particle energy is not conserved. Recently, it has been shown how to construct a theory dubbed "completely quantized collapse" (CQC) which is predictively equivalent to CSL. In CQC, a quantized random field is introduced, and CSL's classical random field becomes its eigenvalue. In CQC, energy is conserved, which allows one to understand that energy is conserved in CSL, as the particle's energy gain is compensated by the random field's energy loss. Since the random field has energy, it should have gravitational consequences. For that, one needs to know the random field's energy density. In this paper, it is shown how to construct a symmetric, conserved, energy-momentum-stress-density tensor associated with the quantized random field, even though this field obeys no dynamical equation and has no Lagrangian. Then, three examples are given involving the random field's energy density. One considers interacting particles, the second treats a "cosmological" particle creation model, the third involves the gravity of the random field.

Philip Pearle

2008-08-13

246

Spin-contamination of coupled-cluster wave functions Anna I. Krylov  

E-print Network

Spin-contamination of coupled-cluster wave functions Anna I. Krylov Department of Chemistry-CCD, enables a discussion of the stability of coupled-cluster wave functions in terms of both spin-contamination and a corresponding energy lowering relative to the pure spin solutions. The spin-contamination of V OO-CCD models has

Krylov, Anna I.

247

Short-time-evolved wave functions for solving quantum many-body problems  

E-print Network

converges essentially to the exact ground state in a relatively short time. Thus a short-time evolved wave function can be an excellent approximation to the exact ground state. Such a short-time-evolved wave function can be obtained by factorizing...

Ciftja, O.; Chin, Siu A.

2003-01-01

248

Quantum Monte Carlo: Direct calculation of corrections to trial wave functions and their energies  

E-print Network

ARTICLES Quantum Monte Carlo: Direct calculation of corrections to trial wave functions, Pennsylvania 16802 Received 4 January 2000; accepted 10 March 2000 We report an improved Monte Carlo method Monte Carlo QMC method for the direct calculation of corrections to trial wave functions.1­3 We report

Anderson, James B.

249

Two-frequency mutual coherence function of electromagnetic waves in random  

E-print Network

Two-frequency mutual coherence function of electromagnetic waves in random media: a path-position mutual coherence function of an electromagnetic pulse propagating through turbulent atmosphere of arbitrary strength. The approach presented in this paper was examined in the cases of plane-wave, spherical

Morozov, Alexandre V.

250

A new iterative method for calculating energy levels and wave functions  

NASA Astrophysics Data System (ADS)

We present an efficient iterative method for calculating energy levels and wave functions. The method requires storing only a small number of vectors but allows one to calculate energy levels and wave functions with far fewer matrix-vector products than the filter diagonalization method of Mandelshtam and Taylor. A zeroth-order Hamiltonian is used to precondition a spectral transform Lanczos method.

Huang, Shi-Wei; Carrington, Tucker

2000-05-01

251

An impact of multiple wave reflections in a flat sample on material parameter reconstruction using THz pulsed spectroscopy  

NASA Astrophysics Data System (ADS)

The present paper is dedicated to studying the accuracy of sample material parameter reconstruction using terahertz (THz) pulsed spectroscopy. The technique for characterizing the material parameters of thin flat samples allowing to take into account multiple wave reflections in a flat have been considered. While transmitting through the resonant sample, THz pulse undergoes multiple reflections, which result in satellite pulses in THz waveform. The accuracy of material parameter reconstruction strongly depends on the number of satellite pulses. We have analytically estimated an impact of satellite pulses on material parameter reconstruction by considering the local linearization of theoretical sample transfer function based on the model of quasi-Fabry-Perot-resonator.

Zaytsev, Kirill I.; Tsapenko, Konstantin P.; Nosov, Pavel A.; Yurchenko, Stanislav O.

2015-01-01

252

Natural impacts on the Moon and Mars: seismic constrains on the impact shock wave and perspectives in term of crustal and upper mantle imaging.  

NASA Astrophysics Data System (ADS)

Natural Impacts occurring on the surface of telluric planets are important seismic sources for constraining the crustal and upper mantle structure, especially when their impact location and impacting time can be determined by other complementing experiments, such as Earth based flash detection for the Moon or differential orbital imaging of the surface for Mars. When these complementary data are not available, which was the case of Apollo with the exception of artificial impacts, the location of impact as compared to quake is easier, as only their geographical location must be determined from seismic data. We present recent results of the analysis of impact related seismic data gathered by the Apollo Lunar seismic network during the 70th. By using the artificial impact, we first develop a calibrated analysis for extracting the impulse (i.e. mass time impact velocity) from the amplitude of seismic waves, and point out the effect of the generation of ejecta in the seismic impulse. This approach not only allows to constrain the mass of the impacts, but also to constrain the impact frequency-impactor mass relation. By combining both the Apollo long period and short period data, further analysis can be made on the dynamic of the seismic source. The combination of these date provides indeed broadband seismic analysis have been made allowing to constraint the seismic cut-off frequency and source spectrum associated with both natural and artificial impacts. We show that the source cut-off is, as compared to moonquakes, relatively low and around a few Hz for remotely detected impacts. It is also depending not only on the impact size, but also on the impact location, as the seismic radiation of the shock wave depends on the most-upper regolith layers. We finally use our results and forward modeling to prepare the GEMS seismic mission to Mars, considered by NASA for a launch in 2016. In order to have a robust estimation of the rates of seismic detection of impacts, we analyze and model the differences of seismic propagation properties between Mars and the Moon, and use this modeling to estimate the seismic response of impacts on Mars, as a function of both the impactor characteristics (mass and velocity) and epicentral distance. We then use statistical models of impactors, confirmed by both the Apollo seismic observations and the Mars Orbiter impacts observations, to estimate the present flux on Mars and to constrain the rate of seismic impact detection, as well as the expected probability to further locale these events by differential remote sensing. This analysis is performed by taking into account both the expected performances of the VBB seismometer of GEMS and the expected environmental noise after its deployment on the Martian surface. The perspectives in terms of crustal and upper mantle seismic imaging are finally provided in conclusion for both GEMS on Mars and SELENE2 on the Moon.

Lognonne, P.; Gudkova, T.; Le Feuvre, M.; Garcia, R. F.; Kawamura, T.; Banerdt, B.; Kobayashi, N.

2011-12-01

253

Ground state wave functionals for $1+1$-dimensional fermion field theories  

E-print Network

We use path-\\-integral methods to derive the ground state wave functions of a number of two-\\-dimensional fermion field theories and related systems in one-\\-dimensional many body physics. We derive the exact wave function for the Thirring/Luttinger and Coset fermion models and apply our results to derive the universal behavior of the wave functions of the Heisenberg antiferromagnets and of the Sutherland model. We find explicit forms for the wave functions in the density and in the Grassmann representations. We show that these wave functions always have the Jastrow factorized form and calculated the exponent. Our results agree with the exponents derived from the Bethe Ansatz for the Sutherland model and the Haldane-\\-Shastri spin chain but apply to all the systems in the same universality class.

Eduardo Fradkin; Enrique Moreno; Fidel A. Schaposnik

1992-07-01

254

The study of leading twist light cone wave function of ?_c meson  

E-print Network

This paper is devoted to the study of leading twist light cone wave function of $\\eta_c$ meson. The moments of this wave function have been calculated within three approaches: potential models, nonrelativistic QCD and QCD sum rules. Using the results obtained within these approaches the model for the light cone wave function of leading twist has been proposed. Being scale dependent light cone wave function has very interesting properties at scales $\\mu> m_c$: improvement of the accuracy of the model, appearance of relativistic tail and violation of nonrelativistic QCD velocity scaling rules. The last two properties are the properties of real leading twist light cone wave function of $\\eta_c$ meson.

V. V. Braguta; A. K. Likhoded; A. V. Luchinsky

2007-01-15

255

On Transverse-Momentum Dependent Light-Cone Wave Functions of Light Mesons  

E-print Network

Transverse-momentum dependent (TMD) light-cone wave functions of a light meson are important ingredients in the TMD QCD factorization of exclusive processes. This factorization allows one conveniently resum Sudakov logarithms appearing in collinear factorization. The TMD light-cone wave functions are not simply related to the standard light-cone wave functions in collinear factorization by integrating them over the transverse momentum. We explore relations between TMD light-cone wave functions and those in the collinear factorization. Two factorized relations can be found. One is helpful for constructing models for TMD light-cone wave functions, and the other can be used for resummation. These relations will be useful to establish a link between two types of factorization.

J. P. Ma; Q. Wang

2006-09-04

256

In situ measurements of impact-induced pressure waves in sandstone targets  

NASA Astrophysics Data System (ADS)

In the present study we introduce an innovative method for the measurement of impact-induced pressure waves within geological materials. Impact experiments on dry and water-saturated sandstone targets were conducted at a velocity of 4600 m/s using 12 mm steel projectiles to investigate amplitudes, decay behavior, and speed of the waves propagating through the target material. For this purpose a special kind of piezoresistive sensor capable of recording transient stress pulses within solid brittle materials was developed and calibrated using a Split-Hopkinson pressure bar. Experimental impact parameters (projectile size and speed) were kept constant and yielded reproducible signal curves in terms of rise time and peak amplitudes. Pressure amplitudes decreased by 3 orders of magnitude within the first 250 mm (i.e., 42 projectile radii). The attenuation for water-saturated sandstone is higher compared to dry sandstone which is attributed to dissipation effects caused by relative motion between bulk material and interstitial water. The proportion of the impact energy radiated as seismic energy (seismic efficiency) is in the order of 10-3. The present study shows the feasibility of real-time measurements of waves caused by hypervelocity impacts on geological materials. Experiments of this kind lead to a better understanding of the processes in the crater subsurface during a hypervelocity impact.

Hoerth, Tobias; Schäfer, Frank; Nau, Siegfried; Kuder, Jürgen; Poelchau, Michael H.; Thoma, Klaus; Kenkmann, Thomas

2014-10-01

257

Equality Impact Assessment Summary Name of policy, function or service  

E-print Network

Equality Impact Assessment Summary Name of policy, function or service Health and Well or service This policy, written by FCW, has been developed on behalf of the Welsh Assembly Government (WAG). Its purpose is to define WAGs position on health and well-being benefits from Welsh woodlands

258

The impact of soil degradation on soil functioning in Europe  

Microsoft Academic Search

The European Commission has presented in September 2006 its Thematic Strategy for Soil Protection.The Thematic Strategy for Soil Protection consists of a Communication from the Commission to the other European Institutions, a proposal for a framework Directive (a European law), and an Impact Assessment. The Communication (COM(2006) 231) sets the frame. It defines the relevant soil functions for Europe and

Luca Montanarella

2010-01-01

259

RESEARCH Open Access Functional impact of Aurora A-mediated  

E-print Network

RESEARCH Open Access Functional impact of Aurora A-mediated phosphorylation of HP1 at serine 83 division, HP1 colocalizes and is phosphorylated at serine 83 (Ser83 ) in G2/M phase by Aurora A. Since Aurora A regulates both cell proliferation and mitotic aberrations, we evaluated the role of HP1

Boyer, Edmond

260

The function of 'brain waves': a cybernetic model of electroencephalography.  

PubMed

Electroencephalograms recorded from sleeping subjects are reinterpreted, from first principles, to explain the relationship between the observed wave-forms and cerebral processes. The manifestations of narcolepsy, namely, sleep paralysis, hypnopompic hallucinations and cataplexy are consistent with a hypothesis that the disorder is the result of entrainment of cerebral waves, causing almost instantaneous descent into a REM sleep state. PMID:14592793

ben-Aaron, M

2003-01-01

261

The East Atlantic - West Russia Teleconnection in the North Atlantic: Climate Impact and Relation to Rossby Wave Propagation  

NASA Technical Reports Server (NTRS)

Large-scale winter teleconnection of the East Atlantic - West Russia (EA-WR) over the Atlantic and surrounding regions is examined in order to quantify its impacts on temperature and precipitation and identify the physical mechanisms responsible for its existence. A rotated empirical orthogonal function (REOF) analysis of the upper-tropospheric monthly height field captures successfully the EA-WR pattern and its interannual variation, with the North Atlantic Oscillation as the first mode. EA-WRs climate impact extends from eastern North America to Eurasia. The positive (negative) EA-WR produces positive (negative) temperature anomalies over the eastern US, western Europe and Russia east of Caspian Sea, with negative (positive) anomalies over eastern Canada, eastern Europe including Ural Mountains and the Middle East. These anomalies are largely explained by lower-tropospheric temperature advections. Positive (negative) precipitation anomalies are found over the mid-latitude Atlantic and central Russia around 60E, where lower-level cyclonic (anticyclonic) circulation anomaly is dominant. The eastern Canada and the western Europe are characterized by negative (positive) precipitation anomalies.The EA-WR is found to be closely associated with Rossby wave propagation. Wave activity fluxes show that it is strongly tied to large-scale stationary waves. Furthermore, a stationary wave model (SWM) forced with vorticity transients in the mid-latitude Atlantic (approximately 40N) or diabatic heat source over the subtropical Atlantic near the Caribbean Sea produces well-organized EA-WR-like wave patterns, respectively. Sensitivity tests with the SWM indicate improvement in the simulation of the EA-WR when the mean state is modified to have a positive NAO component that enhances upper-level westerlies between 40-60N.

Lim, Young-Kwon

2014-01-01

262

Projections of heat waves with high impact on human health in Europe  

NASA Astrophysics Data System (ADS)

Climate change will result in more intense, more frequent and longer lasting heat waves. The most hazardous conditions emerge when extreme daytime temperatures combine with warm night-time temperatures, high humidities and light winds for several consecutive days. Here, we assess present and future heat wave impacts on human health in Europe. Present daily physiologically equivalent temperatures (PET) are derived from the ERA-Interim reanalysis. PET allows to specifically focus on heat-related risks on humans. Regarding projections, a suite of high-resolution regional climate models - run under SRES A1B scenario - has been used. A quantile-quantile adjustment is applied to the daily simulated PET to correct biases in individual model climatologies and a multimodel ensemble strategy is adopted to encompass model errors. Two types of heat waves differently impacting human health - strong and extreme stress - are defined according to specified thresholds of thermal stress and duration. Heat wave number, frequency, duration and amplitude are derived for each type. Results reveal relatively strong correlations between the spatial distribution of strong and extreme heat wave amplitudes and mortality excess for the 2003 European summer. Projections suggest a steady increase and a northward extent of heat wave attributes in Europe. Strong stress heat wave frequencies could increase more than 40 days, lasting over 20 days more by 2075-2094. Amplitudes might augment up to 7 °C per heat wave day. Important increases in extreme stress heat wave attributes are also expected: up to 40 days in frequency, 30 days in duration and 4 °C in amplitude. We believe that with this information at hand policy makers and stakeholders on vulnerable populations to heat stress can respond more effectively to the future challenges imposed by climate warming.

Amengual, A.; Homar, V.; Romero, R.; Brooks, H. E.; Ramis, C.; Gordaliza, M.; Alonso, S.

2014-08-01

263

The impact of heat waves on mortality in 9 European cities: results from the EuroHEAT project  

Microsoft Academic Search

BACKGROUND: The present study aimed at developing a standardized heat wave definition to estimate and compare the impact on mortality by gender, age and death causes in Europe during summers 1990-2004 and 2003, separately, accounting for heat wave duration and intensity. METHODS: Heat waves were defined considering both maximum apparent temperature and minimum temperature and classified by intensity, duration and

Daniela D'Ippoliti; Paola Michelozzi; Claudia Marino; Francesca de'Donato; Bettina Menne; Klea Katsouyanni; Ursula Kirchmayer; Antonis Analitis; Mercedes Medina-Ramón; Anna Paldy; Richard Atkinson; Sari Kovats; Luigi Bisanti; Alexandra Schneider; Agnès Lefranc; Carmen Iñiguez; Carlo A Perucci

2010-01-01

264

Impact of high-frequency nonlinear internal waves on plankton dynamics in Massachusetts Bay  

E-print Network

Impact of high-frequency nonlinear internal waves on plankton dynamics in Massachusetts Bay dynamics in Massachusetts Bay (MB) during the stratified summer season. The temporal and spatial in Massachusetts Bay (MB) is based on the early study of Haury et al. (1979, 1983) (Fig. 1). They suggested

Chen, Changsheng

265

Wave Shaping and Lateral Spreading of Impact Loads Using Layered Materials and Structures  

Microsoft Academic Search

The overall objective of our work is to explore a new concept for developing resilient armor using high wave speed layers to rapidly spread the loads arising from projectile impacts. Because layered structures involve many additional geometrical and material variables, and because layers affect stress distribution and energy absorption capability of the target, a fundamental issue in determining layering effects

J. L. Ding; J. Robbins; Y. M. Gupta; M. K. Wong

1999-01-01

266

Satellite remote sensing data for urban heat waves assessment and human health impacts  

NASA Astrophysics Data System (ADS)

Remote sensing is a key application in global-change science and urban climatology. Urbanization, the conversion of other types of land to uses associated with growth of populations and economy has a great impact on both micro-climate as well as macro-climate. By integrating high-resolution and medium-resolution satellite imagery with other geospatial information, have been investigated several land surface parameters including impervious surfaces and land surface temperatures for Bucharest metropolitan area in Romania. The aim of this study is to examine the changes in land use/cover pattern in a rapidly changing area of Bucharest in relation to urbanization since the 1990s till 2011 and then to investigate the impact of such changes on the intensity and spatial pattern of the UHI (Urban Heat Island) effect in the region in relation with heat waves assessment. Investigation of radiative properties, energy balance, heat fluxes and NDVI, EVI is based on satellite data provided by various sensors Landsat TM/ETM, ASTER, MODIS and IKONOS. A detailed analysis was done for summer 2003, 2007 and 2010 years heat wave events in and related impacts on human health. So called effect of "urban heat island" must be considered mostly for summer periods conditions and large European scale heat waves. As future climate trends have been predicted to increase the magnitude and negative impacts of urban heat waves in Bucharest metropolitan area, there is an urgent need to be developed adequate strategies for societal vulnerability reducing.

Zoran, M. A.; Dida, M. R.

2012-10-01

267

Impact of current-wave interaction on storm surge simulation: A case study for Hurricane Bob  

E-print Network

, especially following Hurricane Katrina in 2005, hurricane-induced storm surge and coastal inundation haveImpact of current-wave interaction on storm surge simulation: A case study for Hurricane Bob,2 Received 2 January 2013; revised 5 April 2013; accepted 18 April 2013; published 30 May 2013. [1] Hurricane

Chen, Changsheng

268

Europe's 2003 heat wave: a satellite view of impacts and land–atmosphere feedbacks  

Microsoft Academic Search

ABSTRACT A combination of satellite imagery, meteorological station data, and the NCEP\\/NCAR reanalysis has been used to explore the spatial and temporal evolution of the 2003 heat wave in France, with focus on understanding the impacts and feedbacks at the land surface. Vegetation was severely affected across the study area, especially in a swath across central France that corresponds,to the

Benjamin F. Zaitchik; Alison K. Macalady; Laurent R. Bonneau; Ronald B. Smith

2006-01-01

269

EUROPE'S 2003 HEAT WAVE: A SATELLITE VIEW OF IMPACTS AND LAND-ATMOSPHERE FEEDBACKS  

Microsoft Academic Search

A combination of satellite imagery, meteorological station data, and the NCEP\\/NCAR reanalysis has been used to explore the spatial and temporal evolution of the 2003 heat wave in France, with focus on understanding the impacts and feedbacks at the land surface. Vegetation was severely affected across the study area, especially in a swath across central France that corresponds to the

BENJAMIN F. ZAITCHIK; ALISON K. MACALADY; RONALD B. SMITHd

270

Europe's 2003 heat wave: a satellite view of impacts and land-atmosphere feedbacks  

Microsoft Academic Search

A combination of satellite imagery, meteorological station data, and the NCEP\\/NCAR reanalysis has been used to explore the spatial and temporal evolution of the 2003 heat wave in France, with focus on understanding the impacts and feedbacks at the land surface. Vegetation was severely affected across the study area, especially in a swath across central France that corresponds to the

Benjamin F. Zaitchik; Alison K. Macalady; Laurent R. Bonneau; Ronald B. Smith

2006-01-01

271

Geographical differences on the mortality impact of heat waves in Europe  

Microsoft Academic Search

Climate change is potentially the biggest global health threat in the 21st century. Deaths related with heat waves and spread of infectious diseases will be part of the menace though the major impact will be caused by malnutrition, diarrhea and extreme climate events. Consequently, loss of healthy life years as a result of global climate change is predicted to be

Jordi Sunyer

2010-01-01

272

Electron-impact excitation-autoionization of helium in the S-wave limit  

SciTech Connect

Excitation of the autoionizing states of helium by electron impact is shown in calculations in the s-wave limit to leave a clear signature in the singly differential cross section for the (e,2e) process. It is suggested that such behavior should be seen generally in (e,2e) experiments on atoms that measure the single differential cross section.

Horner, Daniel A.; McCurdy, C. William; Rescigno, Thomas N.

2004-10-01

273

Correlated wave functions for the ground and some excited states of the iron atom.  

PubMed

We study the states arising from the [Ar]4s(2)3d6 and [Ar]4s(1)3d7 configurations of iron atom with explicitly correlated wave functions. The variational wave function is the product of the Jastrow correlation factor times a model function obtained within the parametrized optimized effective potential framework. A systematic analysis of the dependence of both the effective potential and the correlation factor on the configuration and on the term is carried out. The ground state of both, the cation, Fe+, and anion, Fe-, are calculated with correlated wave functions and the ionization potential and the electron affinity are obtained. PMID:16674212

Buendía, E; Gálvez, F J; Sarsa, A

2006-04-21

274

Impact of heat waves on mortality in Croatia.  

PubMed

The aim of this work was to determine the criteria for heat loads associated with an increase in mortality in different climatic regions of Croatia. The relationship between heat stress and mortality was analysed for the period 1983-2008. The input series is excess mortality defined as the deviations of mortality from expected values determined by means of a Gaussian filter of 183 days. The assessment of the thermal environment was performed by means of physiologically equivalent temperature (PET). The curve depicting the relationship between mortality and temperature has a U shape, with increased mortality in both the cold and warm parts of the scale but more pronounced in the warm part. The threshold temperature for increased mortality was determined using a scatter plot and fitting data by means of moving average of mortality; the latter is defined as the temperature at which excess mortality becomes significant. The values are higher in the continental part of Croatia than at the coast due to the refreshing influence of the sea during the day. The same analysis on a monthly basis shows that at the beginning of the warm season increased mortality occurs at a lower temperature compared with later on in the summer, and the difference is up to 15 °C between August and April. The increase in mortality is highest during the first 3-5 days and after that it decreases and falls below the expected value. Long-lasting heat waves present an increased risk, but in very long heat waves the increase in mortality is reduced due to mortality displacement. PMID:23995621

Zaninovi?, Ksenija; Matzarakis, Andreas

2014-08-01

275

Single impact crater functions for ion bombardment of silicon  

SciTech Connect

The average effect of a single 500 eV incident argon ion on a silicon surface is studied using molecular dynamics simulations. More than 10{sup 3} ion impacts at random surface points are averaged for each of seven incidence angles, from 0 deg. to 28 deg. off normal, to determine a local surface height change function, or a crater function. The crater shapes are mostly determined by mass rearrangement; sputtering has a relatively small effect. Analytical fitting functions are provided for several cases, and may serve as input into kinetic Monte Carlo calculations or stability analyses for surfaces subjected to ion bombardment.

Kalyanasundaram, N.; Ghazisaeidi, M.; Freund, J. B.; Johnson, H. T. [Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 (United States)

2008-03-31

276

Impact of IQ Discrepancy on Executive Function in High-Functioning Autism: Insight into Twice Exceptionality  

ERIC Educational Resources Information Center

We examined the impact of IQ discrepancy (IQD) within (1) and above (1+) one standard deviation on executive function in HFA using the BRIEF. We hypothesized that IQD would benefit executive function. IQD 1 is hallmarked by deficits in BRIEF indices and subscales inhibit, shift, initiate, working memory, planning and organization, and monitor…

Kalbfleisch, M. Layne; Loughan, Ashlee R.

2012-01-01

277

Decomposition of the unsteady wave patterns for Bessho form translating-pulsating source green function  

NASA Astrophysics Data System (ADS)

In order to interpret the physical feature of Bessho form translating-pulsating source Green function, the phase function is extracted from the integral representation and stationary-phase analysis is carried out in this paper. The complex characteristics of the integral variable and segmentation of the integral intervals are discussed in m complex plane. In ? space, the interval [-?/2+ ?, -?/2+ ?-i ?] is dominant in the near-field flow, and there is a one-to-one correspondence between the real intervals in m space and the unsteady wave patterns in far field. If 4 ?>1 ( ? is the Brard number), there are three kinds of propagation wave patterns such as ring-fan wave pattern, fan wave pattern and inner V wave pattern, and if 0<4 ?<1, a ring wave pattern, an outer V and inner V wave pattern are presented in far field. The ring-fan or ring wave pattern corresponds to the interval [-?+ ?, -?/2+ ?] for integral terms about k 2, and the fan or outer V wave pattern and inner V wave pattern correspond to [-?+ ?, -?/2) and (-?/2, -?/2+ ?] respectively for terms about k 1. Numerical result shows that it is beneficial to decompose the unsteady wave patterns under the condition of ??0 by converting the integral variable ? to m. In addition, the constant-phase curve equations are derived when the source is performing only pulsating or translating.

Xiao, Wenbin; Dong, Wencai

2014-10-01

278

Coherent cooling of atoms in a frequency-modulated standing laser wave: Wave function and stochastic trajectory approaches  

SciTech Connect

The wave function of a moderately cold atom in a stationary near-resonant standing light wave delocalizes very fast due to wave packet splitting. However, we show that frequency modulation of the field can suppress packet splitting for some atoms whose specific velocities are in a narrow range. These atoms remain localized in a small space for a long time. We demonstrate and explain this effect numerically and analytically. We also demonstrate that the modulated field can not only trap but also cool the atoms. We perform a numerical experiment with a large atomic ensemble having wide initial velocity and energy distributions. During the experiment, most of atoms leave the wave while the trapped atoms have a narrow energy distribution.

Argonov, V. Yu., E-mail: argonov@poi.dvo.ru [Russian Academy of Sciences, Pacific Oceanological Institute (Russian Federation)

2014-11-15

279

Temporomandibular joint disorders' impact on pain, function, and disability.  

PubMed

The aim of this study was to determine the association between more advanced stages of temporomandibular joint (TMJ) intra-articular disorders ("TMJ intra-articular status"), representing a transition from normal joint structure to TMJ disc displacement with and without reduction (DDwR and DDwoR) to degenerative joint disease (DJD), and patient-reported outcomes of jaw pain, function, and disability ("TMD impact"). This cross-sectional study included 614 cases from the RDC/TMD Validation Project with at least one temporomandibular disorder (TMD) diagnosis. TMJ intra-articular status was determined by 3 blinded, calibrated radiologists using magnetic resonance imaging and computed tomography as one of normal joint structure, DDwR, DDwoR, or DJD, representing the subject's most advanced TMJ diagnosis. TMD impact was conceptualized as a latent variable consisting of 1) pain intensity (Characteristic Pain Index from the Graded Chronic Pain Scale [GCPS]), 2) jaw function (Jaw Functional Limitation Scale), and 3) disability (Disability Points from GCPS). A structural equation model estimated the association of TMJ intra-articular status with the latent measure TMD impact as a correlation coefficient in all TMD cases (n = 614) and in cases with a TMD pain diagnosis (n = 500). The correlations between TMJ intra-articular status and TMD impact were 0.05 (95% confidence interval [CI], -0.04 to 0.13) for all TMD cases and 0.07 (95% CI, -0.04 to 0.17) for cases with a pain diagnosis, which are neither statistically significant nor clinically relevant. Conceptualizing worsening of TMJ intra-articular disorders as 4 stages and characterizing impact from TMD as a composite of jaw pain, function, and disability, this cross-sectional study found no clinically significant association. Models of TMJ intra-articular status other than ours (normal structure ? DDwR ? DDwoR ? DJD) should be explored. PMID:25572112

Chantaracherd, P; John, M T; Hodges, J S; Schiffman, E L

2015-03-01

280

Coherent molecular transistor: Control through variation of the gate wave function  

SciTech Connect

In quantum interference transistors (QUITs), the current through the device is controlled by variation of the gate component of the wave function that interferes with the wave function component joining the source and the sink. Initially, mesoscopic QUITs have been studied and more recently, QUITs at the molecular scale have been proposed and implemented. Typically, in these devices the gate lead is subjected to externally adjustable physical parameters that permit interference control through modifications of the gate wave function. Here, we present an alternative model of a molecular QUIT in which the gate wave function is directly considered as a variable and the transistor operation is discussed in terms of this variable. This implies that we specify the gate current as well as the phase of the gate wave function component and calculate the resulting current through the source-sink channel. Thus, we extend on prior works that focus on the phase of the gate wave function component as a control parameter while having zero or certain discrete values of the current. We address a large class of systems, including finite graphene flakes, and obtain analytic solutions for how the gate wave function controls the transistor.

Ernzerhof, Matthias, E-mail: Matthias.Ernzerhof@UMontreal.ca [Département de Chimie, Université de Montréal, C.P. 6128 Succursale A, Montréal, Quebec H3C 3J7 (Canada)] [Département de Chimie, Université de Montréal, C.P. 6128 Succursale A, Montréal, Quebec H3C 3J7 (Canada)

2014-03-21

281

Longitudinal wave function control in single quantum dots with an applied magnetic field.  

PubMed

Controlling single-particle wave functions in single semiconductor quantum dots is in demand to implement solid-state quantum information processing and spintronics. Normally, particle wave functions can be tuned transversely by an perpendicular magnetic field. We report a longitudinal wave function control in single quantum dots with a magnetic field. For a pure InAs quantum dot with a shape of pyramid or truncated pyramid, the hole wave function always occupies the base because of the less confinement at base, which induces a permanent dipole oriented from base to apex. With applying magnetic field along the base-apex direction, the hole wave function shrinks in the base plane. Because of the linear changing of the confinement for hole wave function from base to apex, the center of effective mass moves up during shrinking process. Due to the uniform confine potential for electrons, the center of effective mass of electrons does not move much, which results in a permanent dipole moment change and an inverted electron-hole alignment along the magnetic field direction. Manipulating the wave function longitudinally not only provides an alternative way to control the charge distribution with magnetic field but also a new method to tune electron-hole interaction in single quantum dots. PMID:25624018

Cao, Shuo; Tang, Jing; Gao, Yunan; Sun, Yue; Qiu, Kangsheng; Zhao, Yanhui; He, Min; Shi, Jin-An; Gu, Lin; Williams, David A; Sheng, Weidong; Jin, Kuijuan; Xu, Xiulai

2015-01-01

282

Longitudinal wave function control in single quantum dots with an applied magnetic field  

NASA Astrophysics Data System (ADS)

Controlling single-particle wave functions in single semiconductor quantum dots is in demand to implement solid-state quantum information processing and spintronics. Normally, particle wave functions can be tuned transversely by an perpendicular magnetic field. We report a longitudinal wave function control in single quantum dots with a magnetic field. For a pure InAs quantum dot with a shape of pyramid or truncated pyramid, the hole wave function always occupies the base because of the less confinement at base, which induces a permanent dipole oriented from base to apex. With applying magnetic field along the base-apex direction, the hole wave function shrinks in the base plane. Because of the linear changing of the confinement for hole wave function from base to apex, the center of effective mass moves up during shrinking process. Due to the uniform confine potential for electrons, the center of effective mass of electrons does not move much, which results in a permanent dipole moment change and an inverted electron-hole alignment along the magnetic field direction. Manipulating the wave function longitudinally not only provides an alternative way to control the charge distribution with magnetic field but also a new method to tune electron-hole interaction in single quantum dots.

Cao, Shuo; Tang, Jing; Gao, Yunan; Sun, Yue; Qiu, Kangsheng; Zhao, Yanhui; He, Min; Shi, Jin-An; Gu, Lin; Williams, David A.; Sheng, Weidong; Jin, Kuijuan; Xu, Xiulai

2015-01-01

283

Longitudinal wave function control in single quantum dots with an applied magnetic field  

E-print Network

Controlling single-particle wave functions in single semiconductor quantum dots is in demand to implement solid-state quantum information processing and spintronics. Normally, particle wave functions can be tuned transversely by an perpendicular magnetic field. We report a longitudinal wave function control in single quantum dots with a magnetic field. For a pure InAs quantum dot with a shape of pyramid or truncated pyramid, the hole wave function always occupies the base because of the less confinement at base, which induces a permanent dipole oriented from base to apex. With applying magnetic field along the base-apex direction, the hole wave function shrinks in the base plane. Because of the linear changing of the confinement for hole wave function from base to apex, the center of effective mass moves up during shrinking process. Due to the uniform confine potential for electrons, the center of effective mass of electrons does not move much, which results in a permanent dipole moment change and an inverted electron-hole alignment along the magnetic field direction. Manipulating the wave function longitudinally not only provides an alternative way to control the charge distribution with magnetic field but also a new method to tune electron-hole interaction in single quantum dots.

Shuo Cao; Jing Tang; Yunan Gao; Yue Sun; Kangsheng Qiu; Yanhui Zhao; Min He; Jin-An Shi; Lin Gu; David A. Williams; Weidong Sheng; Kuijuan Jin; Xiulai Xu

2015-01-29

284

How child's play impacts executive function--related behaviors.  

PubMed

Executive functions refer to an array of organizing and self-regulating behaviors often associated with maturation of the prefrontal cortex. In fact, young children with rudimentary neurodevelopment of the prefrontal cortex develop ways to inhibit impulses and regulate behavior from a very early age. Can executive functioning be impacted by intervention, practice, or training? What interventions impact development of executive function in childhood, and how can these be studied? Several programs are reviewed that propose to positively impact executive/self-regulation skills. Evidence-based programs are contrasted with popular programs that have little empirical basis but have apparent wide acceptance by educators and families. As self-regulation has critical implications for later school and life success, interventions may well attenuate the negative consequences of attention-deficit hyperactivity disorder, brain injury, and social stressors. Programs with active play components may be more successful in eliciting improved executive function (defined here as self-regulation) because of the importance of motor learning early on and because of the social motivation aspects of learning. Caution is advised in the recommendation of programs where there is little empirical basis to support program claims. Carefully planned outcome studies can help bring the most effective components of programs to the mainstream. PMID:25010084

Shaheen, Sandra

2014-01-01

285

Remarks on nodal volume statistics for regular and chaotic wave functions in various dimensions  

E-print Network

We discuss the statistical properties of the volume of the nodal set of wave function for two paradigmatic model systems which we consider in arbitrary dimension $s\\ge 2$: the cuboid as a paradigm for a regular shape with separable wave functions, planar random waves as an established model for chaotic wave functions in irregular shapes. We give explicit results for the mean and variance of the nodal volume in arbitrary dimension, and for their limiting distribution. For the mean nodal volume we calculate the effect of the boundary of the cuboid where Dirichlet boundary conditions reduce the nodal volume compared to the bulk. Boundary effects for chaotic wave functions are calculated using random waves which satisfy a Dirichlet boundary condition on a hyperplane. We put forward several conjectures what properties of cuboids generalise to general regular shapes with separable wave functions and what properties of random waves can be expected for general irregular shapes. These universal features clearly distinct between the two cases.

Sven Gnutzmann; Stylianos Lois

2012-12-19

286

Spectrum and Wave Functions of Excited States in Lattice Gauge Theory  

E-print Network

We suggest a new method to compute the spectrum and wave functions of excited states. We construct a stochastic basis of Bargmann link states, drawn from a physical probability density distribution and compute transition amplitudes between stochastic basis states. From such transition matrix we extract wave functions and the energy spectrum. We apply this method to $U(1)_{2+1}$ lattice gauge theory. As a test we compute the energy spectrum, wave functions and thermodynamical functions of the electric Hamiltonian and compare it with analytical results. We find excellent agreement. We observe scaling of energies and wave functions in the variable of time. We also present first results on a small lattice for the full Hamiltonian including the magnetic term.

H. Kroger; A. Hosseinizadeh; J. F. Laprise; J. Kroger

2009-02-17

287

A test of a mechanical multi-impact shear-wave seismic source  

USGS Publications Warehouse

We modified two gasoline-engine-powered earth tampers, commonly used as compressional-(P) wave seismic energy sources for shallow reflection studies, for use as shear(S)-wave energy sources. This new configuration, termed ?Hacker? (horizontal Wacker?), is evaluated as an alternative to the manual sledgehammer typically used in conjunction with a large timber held down by the front wheels of a vehicle. The Hacker maximizes the use of existing equipment by a quick changeover of bolt-on accessories as opposed to the handling of a separate source, and is intended to improve the depth of penetration of S-wave data by stacking hundreds of impacts over a two to three minute period. Records were made with a variety of configurations involving up to two Hackers simultaneously then compared to a reference record made with a sledgehammer. Preliminary results indicate moderate success by the higher amplitude S-waves recorded with the Hacker as compared to the hammer method. False triggers generated by the backswing of the Hacker add unwanted noise and we are currently working to modify the device to eliminate this effect. Correlation noise caused by insufficient randomness of the Hacker impact sequence is also a significant noise problem that we hope to reduce by improving the coupling of the Hacker to the timber so that the operator has more control over the impact sequence.

Worley, David M.; Odum, Jack K.; Williams, Robert A.; Stephenson, William J.

2001-01-01

288

The Hartle-Hawking wave function in 2d causal set quantum gravity  

E-print Network

We define the Hartle-Hawking no-boundary wave function for causal set quantum gravity over the discrete analogs of spacelike hypersurfaces. Using Markov Chain Monte Carlo and numerical integration methods we analyse this wave function in non perturbative 2d causal set quantum gravity. Our results provide new insights into the role of quantum gravity in the observable universe. We find that non-manifold contributions to the Hartle-Hawking wave function can play a significant role. These discrete geometries exhibit a rapid spatial expansion with respect to the proper time and also possess a spatial homogeneity consistent with our current understanding of the observable universe.

Lisa Glaser; Sumati Surya

2014-11-13

289

Small-x behavior of light-cone wave functions in transverse lattice gauge theory  

SciTech Connect

We study the behavior of light-cone wave functions, in coarse transverse lattice gauge theory, when one or more parton light-cone momenta are small. This probes the limit of hadron structure at large and small Bjorken x. Finite-energy boundary conditions on boundstates allow one to derive the analytic form of wave functions in this region. This leads to simple, universal predictions for the behavior of quark generalized parton distributions near their endpoints. For the first few meson wave functions at large N{sub c}, we give the simplest ansatz that incorporates all the boundary conditions.

Bratt, J.; Sande, B. van de; Watson, E.M. [Geneva College, 3200 College Avenue, Beaver Falls, Pennsylvania 15010 (United States); Dalley, S. [Department of Physics, University of Wales Swansea, Singleton Park, Swansea SA2 8PP (United Kingdom)

2004-12-01

290

Pion Light-Cone Wave Functions and Light-Front Quark Model  

E-print Network

We discuss a relation between the light-front quark model and QCD. We argue that this model can be used for an evaluation of the light-cone wave functions for moderate values of "u", but that it is inapplicable for this purpose in the region near the ends points u=0,1. We find additional support for a recent analysis in which it was claimed that the twist-two pion wave function attains its asymptotic form. The asymptotic twist-four two-particle wave function is also in good agreement with the light-front quark model.

V. M. Belyaev; Mikkel B. Johnson

1997-12-05

291

Detection of gravitational waves in Michelson interferometer by the use of second order correlation functions  

E-print Network

The possibility of measuring the second order correlation function of the gravitational waves detectors' currents or photonumbers, and the observation of the gravitational signals by using a spectrum analyzer is discussed. The method is based on complicated data processing and is expected to be efficient for coherent periodic gravitational waves. It is suggested as an alternative method to the conventional one which is used now in the gravitational waves observatories.

Y. Ben-Aryeh

2006-12-31

292

The impact of consecutive freshwater trimix dives at altitude on human cardiovascular function.  

PubMed

Self-contained underwater breathing apparatus (SCUBA) diving is regularly associated with numerous asymptomatic changes in cardiovascular function. Freshwater SCUBA diving presents unique challenges compared with open sea diving related to differences in water density and the potential for dive locations at altitude. The aim of this study was to evaluate the impact of freshwater trimix diving at altitude on human cardiovascular function. Ten divers performed two dives in consecutive days at 294 m altitude with the surface interval of 24 h. Both dives were at a depth of 45 m with total dive time 29 and 26 min for the first and second dive, respectively. Assessment of venous gas embolization, hydration status, cardiac function and arterial stiffness was performed. Production of venous gas emboli was low, and there were no significant differences between the dives. After the first dive, diastolic blood pressure was significantly reduced, which persisted up to 24 h. Left ventricular stroke volume decreased, and heart rate increased after both dives. Pulse wave velocity was unchanged following the dives. However, the central and peripheral augmentation index became more negative after both dives, indicating reduced wave reflection. Ejection duration and round trip travel time were prolonged 24 h after the first dive, suggesting longer-lasting suppression of cardiac and endothelial function. This study shows that freshwater trimix dives with conservative profiles and low venous gas bubble loads can result in multiple asymptomatic acute cardiovascular changes some of which were present up to 24 h after dive. PMID:24528802

Lozo, Mislav; Madden, Dennis; Gunjaca, Grgo; Ljubkovic, Marko; Marinovic, Jasna; Dujic, Zeljko

2015-03-01

293

Isgur-Wise function within a QCD quark model with Airy's function as the wave function of heavy-light mesons  

E-print Network

We report some improved wave function for mesons taking linear confinement term in standard QCD potential as parent and Coulombic term as perturbation while applying quantum mechanical perturbation technique in solving Schrodinger equation with such a potential. We find that Airy's infinite series appears in the wave-function of the mesons. We report our calculations on the Isgur-Wise function and its derivatives for heavy-light mesons, within this framework.

Sabyasachi Roy; N. S. Bordoloi; D. K. Choudhury

2012-09-27

294

Sea state projections for the North Sea: Impact of climate change on very high waves?  

NASA Astrophysics Data System (ADS)

The research program KLIWAS of the German Federal Ministry of Transport, Building and urban Development investigates the impacts of climate change on waterways and navigation and provides options for adaptations. One aspect of the research task is to analyse climate scenarios for the sea state, eg. Sea wave height (SWH), wave direction and wave periods for the North Sea. Of particular importance for the safety on waterways is the potential change of frequence and magnitude from severe waves. The scenarios together with the wave climate of the recent years will give an approximation of projected changes of the sea state in coastal and open sea areas. Here we show the results for projected changes of medium, high and very high waves in the North Sea for the period 2000-2100 in comparison to 1961-2000, based on the wave model WAM4.5.3 The wave model is driven with wind data from two different regional atmosphere-ocean-models (DMI-HIRHAM and MPI-REMO) in the scenario A1B. The wind data are delivered in a horizontal resolution of about 20 km and a time resolution of one hour, while the wave model provides data of the calculated sea state with a horizontal grid of 5 km and the time resolution of one hour. It is seen, that in the eastern North Sea and especially in the German Bight there is a trend to a increasing of the 99th percentile of SWH, while in the western part the 99th percentile of SWH decreases in the future. These changes are mainly caused by changing wind directions in the future, while the wind speed will be mostly unaltered. Supplementary, it was carried out an extrem value analysis with the same data. Although the very high waves (eg. waves with a return period of 1-, 5-, 10-, up to 100 years) displays a similar behavior as the median or 99th percentile, there are regions in the North Sea (eg. the German Bight) with stronger changes of the higher waves. For all wave heights a strong decadal variability is detected which superimposes the calculated trends.

Möller, Jens; Groll, Nikolaus; Heinrich, Hartmut

2014-05-01

295

Gravity wave propagation in the realistic atmosphere based on a three-dimensional transfer function model  

Microsoft Academic Search

In order to study the filter effect of the background winds on the propagation of gravity waves, a three-dimensional transfer function model is developed on the basis of the complex dispersion relation of internal gravity waves in a stratified dissipative atmosphere with background winds. Our model has successfully represented the main results of the ray tracing method, e.g. the trend

L. Sun; W. Wan; F. Ding; T. Mao

2007-01-01

296

Functionally graded piezoelectric materials for modal transducers for exciting bulk and surface acoustic waves.  

PubMed

We show that functionally graded piezoelectric materials can be used to make modal actuators through theoretical analyses of the excitation of extensional motion in an elastic rod and Rayleigh surface waves over an elastic half-plane. The results suggest alternatives with certain advantages for the excitation of bulk and surface acoustic waves. PMID:18986946

Yang, Jiashi; Jin, Zhihe; Li, Jiangyu

2008-07-01

297

Random fields of water surface waves using Wiener Hermite functional series expansions  

Microsoft Academic Search

Random motions of irrotational gravity water surface waves on deep water are formulated using the so-called Wiener Hermite functional series expansion, based on the `ideal random process', i.e. the white noise. Such a procedure is known to differ fundamentally from moment expansions such as Gram Charlier or Edgeworth series. The applications concern `free waves' which are homogeneous in the horizontal

Maminirina Joelson; Alfred Ramamonjiarisoa

2003-01-01

298

Ocean wave-radar modulation transfer functions from the West Coast experiment  

NASA Technical Reports Server (NTRS)

Short gravity-capillary waves, the equilibrium, or the steady state excitations of the ocean surface are modulated by longer ocean waves. These short waves are the predominant microwave scatterers on the ocean surface under many viewing conditions so that the modulation is readily measured with CW Doppler radar used as a two-scale wave probe. Modulation transfer functions (the ratio of the cross spectrum of the line-of-sight orbital speed and backscattered microwave power to the autospectrum of the line-of-sight orbital speed) were measured at 9.375 and 1.5 GHz (Bragg wavelengths of 2.3 and 13 cm) for winds up to 10 m/s and ocean wave periods from 2-18 s. The measurements were compared with the relaxation-time model; the principal result is that a source of modulation other than straining by the horizontal component of orbital speed, possibly the wave-induced airflow, is responsible for most of the modulation by waves of typical ocean wave period (10 s). The modulations are large; for unit coherence, spectra of radar images of deep-water waves should be proportional to the quotient of the slope spectra of the ocean waves by the ocean wave frequency.

Wright, J. W.; Plant, W. J.; Keller, W. C.; Jones, W. L.

1980-01-01

299

Impacts and Responses to the 1995 Heat Wave: A Call to Action.  

NASA Astrophysics Data System (ADS)

The short but intense heat wave in mid-July 1995 caused 830 deaths nationally, with 525 of these deaths in Chicago. Many of the dead were elderly. and the event raised great concern over why it happened. Assessment of causes for the heat wave-related deaths in Chicago revealed many factors were at fault, including an inadequate local heat wave warning system, power failures, questionable death assessments, inadequate ambulance service and hospital facilities, the heat island, an aging population, and the inability of many persons to properly ventilate their residences due to fear of crime or a lack of resources for fans or air conditioning. Heat-related deaths appear to be on the increase in the United States. Heat-related deaths greatly exceed those caused by other life-threatening weather conditions. Analysis of the impacts and responses to this heat wave reveals a need to 1) define the heat island conditions during heat waves for all major cities is a means to improve forecasts of threatening conditions, 2) develop a nationally uniform means for classifying heat-related deaths, 3) improve warning systems that are designed around local conditions of large cities, and 4) increase research on the meteorological and climatological aspects of heat stress and heat waves.

Changnon, Stanley A.; Kunkel, Kenneth E.; Reinke, Beth C.

1996-07-01

300

The Dynamic Dielectric at a Brain Functional Site and an EM Wave Approach to Functional Brain Imaging  

PubMed Central

Functional brain imaging has tremendous applications. The existing methods for functional brain imaging include functional Magnetic Resonant Imaging (fMRI), scalp electroencephalography (EEG), implanted EEG, magnetoencephalography (MEG) and Positron Emission Tomography (PET), which have been widely and successfully applied to various brain imaging studies. To develop a new method for functional brain imaging, here we show that the dielectric at a brain functional site has a dynamic nature, varying with local neuronal activation as the permittivity of the dielectric varies with the ion concentration of the extracellular fluid surrounding neurons in activation. Therefore, the neuronal activation can be sensed by a radiofrequency (RF) electromagnetic (EM) wave propagating through the site as the phase change of the EM wave varies with the permittivity. Such a dynamic nature of the dielectric at a brain functional site provides the basis for an RF EM wave approach to detecting and imaging neuronal activation at brain functional sites, leading to an RF EM wave approach to functional brain imaging. PMID:25367217

Li, X. P.; Xia, Q.; Qu, D.; Wu, T. C.; Yang, D. G.; Hao, W. D.; Jiang, X.; Li, X. M.

2014-01-01

301

Proposed experiment with Rydberg atoms to test the wave function interpretation  

E-print Network

Experiment{Fabre_1983} shows that Rydberg atoms do not pass through 1 micronmeter width slits if their principal quantum number is rather large(n > 60). Thus, the particle density measured after the slits is null while the wave function calculated after the slits is not. This experiment is in contradiction with the Born interpretation (the square of the wave function is proportional to the probability density for the particle to be found at each point in space). The classical interpretation of this experiment, which removes the contradiction, is to suppose that if the particles do not pass, the wave function does not pass either (classical assumption). An alternative interpretation of this experiment is to suppose that the wave function passes through the slits, but that the Born interpretation is not valid any more in this case (alternative assumption). The aim of this paper is to present an experiment testing this alternative assumption compared to the classical assumption.

M. Gondran; M. Bozic; D. Arsenovic; A. Gondran

2007-01-15

302

Variation in Differential and Total Cross Sections Due to Different Radial Wave Functions  

ERIC Educational Resources Information Center

Three sets of analytical wave functions are used to calculate the Na (3s---3p) transition differential and total electron excitation cross sections by Born approximations. Results show expected large variations in values. (Author/CP)

Williamson, W., Jr.; Greene, T.

1976-01-01

303

Weak Equivalence Principle and Propagation of the Wave Function in Quantum Mechanics  

E-print Network

The propagation of the wave function of a particle is characterised by a group and a phase velocity. The group velocity is associated with the particle's classical velocity, which is always smaller than the speed of light, and the phase velocity is associated with the propagation speed of the wave function phase and is treated as being unphysical, since its value is always greater than the speed of light. Here we show, using Sciama's Machian formulation of rest mass energy, that this physical interpretation, for the group and the phase velocity of the wave function, is only valid if the weak equivalence principle strictly holds for the propagating particle, except for the photon. In case this constraint is released the phase velocity of the wave function could acquire a physical meaning in quantum condensates.

Clovis Jacinto de Matos

2010-06-14

304

A planetary ultra hypervelocity impact mechanics and shock wave science facility  

NASA Technical Reports Server (NTRS)

Using the concept of intercepting orbits from a pair of Space Station serviced free flyers, a class of impact and shock wave experiments pertinent to planetary science can be performed. One proposed free flying vehicle is an impactor dispensor, and the second is the impact laboratory. How collision is achieved by utilizing essentially twice orbital velocity is demonstrated. The impactor dispensor contains a series of small flyer plates or other projectiles which are launched into the trajectory of the impactor laboratory at appropriate positions. The impactor laboratory is a large impact tank similar to those in terrestrial gun laboratories, except that it contains a supply of targets and instrumentation such as high speed cameras, flash X-ray apparatus, and digital recorders. Shock and isentropic pressures of up to 20 Mbar are achievable with such a system which provides 15 km/sec impact velocities for precisely oriented projectiles.

Ahrens, Thomas J.

1987-01-01

305

A Study on Propagation Characteristic of One-dimensional Stress Wave in Functionally Graded Armor Composites  

NASA Astrophysics Data System (ADS)

The development of Functionally Graded Materials (FGM) for energy-absorbing applications requires understanding of stress wave propagation in these structures in order to optimize their resistance to failure. One-dimensional stress wave in FGM composites under elastic and plastic wave loading have been investigated. The stress distributions through the thickness and stress status have been analyzed and some comparisons have been done with the materials of sharp interfaces (two-layered material). The results demonstrate that the gradient structure design greatly decreases the severity of the stress concentrations at the interfaces and there are no clear differences in stress distribution in FGM composites under elastic and plastic wave loading.

Yang, S. Y.; Liu, X.; Cao, D. F.; Mei, H.; Lei, Z. T.; Liu, L. S.

2013-03-01

306

Data synthesis and display programs for wave distribution function analysis  

NASA Technical Reports Server (NTRS)

At the National Space Science Data Center (NSSDC) software was written to synthesize and display artificial data for use in developing the methodology of wave distribution analysis. The software comprises two separate interactive programs, one for data synthesis and the other for data display.

Storey, L. R. O.; Yeh, K. J.

1992-01-01

307

Composite-fermion wave functions as correlators in conformal field theory  

SciTech Connect

It is known that a subset of fractional quantum Hall wave functions has been expressed as conformal field theory (CFT) correlators, notably the Laughlin wave function [Phys. Rev. Lett. 50, 1395 (1983)] at filling factor {nu}=1/m (m odd) and its quasiholes, and the Pfaffian wave function at {nu}=1/2 and its quasiholes. We develop a general scheme for constructing composite-fermion (CF) wave functions from conformal field theory. Quasiparticles at {nu}=1/m are created by inserting anyonic vertex operators, P{sub 1/m}(z), that replace a subset of the electron operators in the correlator. The one-quasiparticle wave function is identical to the corresponding CF wave function, and the two-quasiparticle wave function has correct fractional charge and statistics and is numerically almost identical to the corresponding CF wave function. We further show how to exactly represent the CF wave functions in the Jain series {nu}=s/(2sp+1) [Phys. Rev. Lett. 63, 199 (1989); Composite Fermions (Cambridge University Press, Cambridge, 2007)] as the CFT correlators of a new type of fermionic vertex operators, V{sub p,n}(z), constructed from n free compactified bosons; these operators provide the CFT representation of composite fermions carrying 2p flux quanta in the nth CF Landau level. We also construct the corresponding quasiparticle and quasihole operators and argue that they have the expected fractional charge and statistics. For filling fractions 2/5 and 3/7, we show that the chiral CFTs that describe the bulk wave functions are identical to those given by Wen's general classification [Int. J. Mod. Phys. B 6, 1711 (1992); Adv. Phys. 44, 405 (1995)] of quantum Hall states in terms of K matrices and l and t vectors, and we propose that to be generally true. Our results suggest a general procedure for constructing quasiparticle wave functions for other fractional Hall states, as well as for constructing ground states at filling fractions not contained in the principal Jain series.

Hansson, T. H. [Department of Physics, Stockholm University, AlbaNova University Center, SE-106 91 Stockholm (Sweden); Chang, C.-C.; Jain, J. K. [Physics Department, 104 Davey Laboratory, Pennsylvania State University, University Park, Pennsylvania 16802 (United States); Viefers, S. [Department of Physics, University of Oslo, P.O. Box 1048, Blindern, 0316 Oslo (Norway)

2007-08-15

308

Convergence of repeated quantum non-demolition measurements and wave function collapse  

E-print Network

Motivated by recent experiments on quantum trapped fields, we give a rigorous proof that repeated indirect quantum non-demolition (QND) measurements converge to the collapse of the wave function as predicted by the postulates of quantum mechanics for direct measurements. We also relate the rate of convergence toward the collapsed wave function to the relative entropy of each indirect measurement, a result which makes contact with information theory.

Michel Bauer; Denis Bernard

2011-10-25

309

Bragg scattering as a probe of atomic wave functions and quantum phase transitions in optical lattices.  

PubMed

We have observed Bragg scattering of photons from quantum degenerate ^{87}Rb atoms in a three-dimensional optical lattice. Bragg scattered light directly probes the microscopic crystal structure and atomic wave function whose position and momentum width is Heisenberg limited. The spatial coherence of the wave function leads to revivals in the Bragg scattered light due to the atomic Talbot effect. The decay of revivals across the superfluid to Mott insulator transition indicates the loss of superfluid coherence. PMID:22107532

Miyake, Hirokazu; Siviloglou, Georgios A; Puentes, Graciana; Pritchard, David E; Ketterle, Wolfgang; Weld, David M

2011-10-21

310

sup 4 He- sup 4 He elastic scattering and variational wave functions  

SciTech Connect

We calculate differential cross sections for {sup 4}He-{sup 4}He elastic scattering at 4.32 GeV/{ital c} in the framework of Glauber multiple scattering theory using correlated variational wave functions as given by the two-nucleon Urbana {ital v}{sub 14} potential and the spin-isospin averaged Melfleit-Tjon force {ital V}. These wave functions are found to give fairly satisfactory results.

Usmani, A.A.; Ahmad, I. (Department of Physics, Aligarh Muslim University, Aligarh-202 002, Uttar Pradesh (India)); Usmani, Q.N. (Department of Physics, Jamia Millia Islamia, New Delhi-110 025 (India))

1992-01-01

311

Multifractal Wave Functions of a System with a Monofractal Energy Spectrum  

NASA Astrophysics Data System (ADS)

We show the appearance of multifractal wave functions on a one-dimensional quasiperiodic system that has a monofractal energy spectrum. Using the Mantica technique, we construct the model as an inverse problem from the energy spectrum of a pure Cantor set. The particle--hole symmetry and a relationship between the critical state and the information dimension are proved. This relationship is applied to the finite-size multifractal analysis of the wave functions.

Tashima, Masayuki; Tasaki, Shuichi

2011-07-01

312

EDF: Computing electron number probability distribution functions in real space from molecular wave functions  

NASA Astrophysics Data System (ADS)

Given an N-electron molecule and an exhaustive partition of the real space ( R) into m arbitrary regions ?,?,…,? ( ?i=1m?=R), the edf program computes all the probabilities P(n,n,…,n) of having exactly n electrons in ?, n electrons in ?,…, and n electrons ( n+n+⋯+n=N) in ?. Each ? may correspond to a single basin (atomic domain) or several such basins (functional group). In the later case, each atomic domain must belong to a single ?. The program can manage both single- and multi-determinant wave functions which are read in from an aimpac-like wave function description ( .wfn) file (T.A. Keith et al., The AIMPAC95 programs, http://www.chemistry.mcmaster.ca/aimpac, 1995). For multi-determinantal wave functions a generalization of the original .wfn file has been introduced. The new format is completely backwards compatible, adding to the previous structure a description of the configuration interaction (CI) coefficients and the determinants of correlated wave functions. Besides the .wfn file, edf only needs the overlap integrals over all the atomic domains between the molecular orbitals (MO). After the P(n,n,…,n) probabilities are computed, edf obtains from them several magnitudes relevant to chemical bonding theory, such as average electronic populations and localization/delocalization indices. Regarding spin, edf may be used in two ways: with or without a splitting of the P(n,n,…,n) probabilities into ? and ? spin components. Program summaryProgram title: edf Catalogue identifier: AEAJ_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEAJ_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 5387 No. of bytes in distributed program, including test data, etc.: 52 381 Distribution format: tar.gz Programming language: Fortran 77 Computer: 2.80 GHz Intel Pentium IV CPU Operating system: GNU/Linux RAM: 55 992 KB Word size: 32 bits Classification: 2.7 External routines: Netlib Nature of problem: Let us have an N-electron molecule and define an exhaustive partition of the physical space into m three-dimensional regions. The edf program computes the probabilities P(n,n,…,n)?P({n}) of all possible allocations of n electrons to ?, n electrons to ?,…, and n electrons to ?,{n} being integers. Solution method: Let us assume that the N-electron molecular wave function, ?(1,N), is a linear combination of M Slater determinants, ?(1,N)=?rMC?(1,N). Calling S?rs the overlap matrix over the 3D region ? between the (real) molecular spin-orbitals (MSO) in ?(?1r,…?Nr) and the MSOs in ?,(?1s,…,?Ns), edf finds all the P({n})'s by solving the linear system ?{n}{?kmtkn}P({n})=?r,sMCCdet[?kmtS?rs], where t=1 and t,…,t are arbitrary real numbers. Restrictions: The number of {n} sets grows very fast with m and N, so that the dimension of the linear system (1) soon becomes very large. Moreover, the computer time required to obtain the determinants in the second member of Eq. (1) scales quadratically with M. These two facts limit the applicability of the method to relatively small molecules. Unusual features: Most of the real variables are of precision real*16. Running time: 0.030, 2.010, and 0.620 seconds for Test examples 1, 2, and 3, respectively. References: [1] A. Martín Pendás, E. Francisco, M.A. Blanco, Faraday Discuss. 135 (2007) 423-438. [2] A. Martín Pendás, E. Francisco, M.A. Blanco, J. Phys. Chem. A 111 (2007) 1084-1090. [3] A. Martín Pendás, E. Francisco, M.A. Blanco, Phys. Chem. Chem. Phys. 9 (2007) 1087-1092. [4] E. Francisco, A. Martín Pendás, M.A. Blanco, J. Chem. Phys. 126 (2007) 094102. [5] A. Martín Pendás, E. Francisco, M.A. Blanco, C. Gatti, Chemistry: A European Journal 113 (2007) 9362-9371.

Francisco, E.; Pendás, A. Martín; Blanco, M. A.

2008-04-01

313

Longitudinal wave function control in single quantum dots with an applied magnetic field  

E-print Network

Controlling single-particle wave functions in single semiconductor quantum dots is in demand to implement solid-state quantum information processing and spintronics. Normally, particle wave functions can be tuned transversely by an perpendicular magnetic field. We report a longitudinal wave function control in single quantum dots with a magnetic field. For a pure InAs quantum dot with a shape of pyramid or truncated pyramid, the hole wave function always occupies the base because of the less confinement at base, which induces a permanent dipole oriented from base to apex. With applying magnetic field along the base-apex direction, the hole wave function shrinks in the base plane. Because of the linear changing of the confinement for hole wave function from base to apex, the center of effective mass moves up during shrinking process. Due to the uniform confine potential for electrons, the center of effective mass of electrons does not move much, which results in a permanent dipole moment change and an inverted...

Cao, Shuo; Gao, Yunan; Sun, Yue; Qiu, Kangsheng; Zhao, Yanhui; He, Min; Shi, Jin-An; Gu, Lin; Williams, David A; Sheng, Weidong; Jin, Kuijuan; Xu, Xiulai

2015-01-01

314

Model wave functions and dynamic correlations in light-medium nuclei  

E-print Network

The nuclei $^4$He, $^8$Be, $^{12}$C and $^{16}$O have been studied starting from nucleon-nucleon interactions of $v_4$ type. The wave function is built as the product of three terms, a Jastrow correlation factor, a linear correlation factor and a model wave function. The correlation factors account for both the short range repulsive and the spin and isospin dependence of the nuclear potential. The model wave function is antisymmetric and has the values of the angular momentum and parity of the state under description. For the model wave function we have used two different schemes. The first one is based on a Harmonic Oscillator shell model with and without deformation, and the second one is based on the Margenau-Brink model of alpha clustering. Projection operators of parity and total angular momentum are used. The performance of these two models is studied and compared systematically. Wave functions for the ground state and some members of its rotational band and some other bound states of these nuclei have been obtained. Binding energies, root mean square radius and the expectation value of the kinetic energy and the different channels of the nuclear interactions and the one-- and two-- body densities are reported. The two different model wave functions and the effects of the different nucleon-nucleon correlations have been evaluated on those quantities. All the results here presented have been obtained by using the Variational Monte Carlo method.

E Buendia; F J Galvez; J Praena; A Sarsa

2004-10-13

315

Light cone nucleon wave function in the quark-soliton model  

E-print Network

The light-cone wave function of the nucleon is calculated in the limit N_c -> infinity in the quark-soliton model inspired by the theory of the instanton vacuum of QCD. The technique of the finite time evolution operator is used in order to derive expressions for all components of the Fock vector describing the nucleon in the infinite momentum frame. It is shown that nucleon wave function for large N_c can be expressed in terms of the wave function of the discrete level in the self-consistent meson field and light cone wave functions of 1,2, etc mesons. The 3-quark components of the nucleon and Delta-resonance are estimated. Wave function of the nucleon appears to be positive in the whole region of x and it has rather small asymmetry. It differs strongly both from Chernyak-Zhitnitsky wave function and the asymptotic one. Large momentum transfer asymptotic of the electromagnetic and axial form factors is discussed.

V. Yu. Petrov; M. V. Polyakov

2003-07-22

316

Impact of water saturation on seismoelectric transfer functions: a laboratory study of coseismic phenomenon  

NASA Astrophysics Data System (ADS)

Seismic waves propagating in a porous medium, under favourable conditions, generate measurable electromagnetic fields due to electrokinetic effects. It has been proposed, following experimental and numerical studies, that these so-called `seismoelectromagnetic' couplings depend on pore fluid properties. The theoretical frame describing these phenomena are based on the original Biot's theory, assuming that pores are fluid-filled. We study here the impact of a partially saturated medium on amplitudes of those seismoelectric couplings by comparing experimental data to an effective fluid model. We have built a 1-m-length-scale experiment designed for imbibition and drainage of an homogeneous silica sand; the experimental set-up includes a seismic source, accelerometers, electric dipoles and capacitance probes in order to monitor seismic and seismoelectric fields during water saturation. Apparent velocities and frequency spectra (in the kiloHertz range) are derived from seismic and electrical measurements during experiments in varying saturation conditions. Amplitudes of seismic and seismoelectric waves and their ratios (i.e. transfer functions) are discussed using a spectral analysis performed by continuous wavelet transform. The experiments reveal that amplitude ratios of seismic to coseismic electric signals remain rather constant as a function of the water saturation in the Sw = [0.2-0.9] range, consistently with theoretically predicted transfer functions.

Bordes, C.; Sénéchal, P.; Barrière, J.; Brito, D.; Normandin, E.; Jougnot, D.

2015-03-01

317

Analyses of Third Order Bose-Einstein Correlation by Means of Coulomb Wave Function  

SciTech Connect

In order to include a correction by the Coulomb interaction in Bose-Einstein correlation (BEC), the wave function for the Coulomb scattering were introduced in the quantum optical approach to BEC in the previous work. If we formulate the amplitude written by Coulomb wave functions according to the diagram for BEC in the plane wave formulation, the formula for 3{pi} -BEC becomes simpler than that of our previous work. We re-analyze the raw data of 3{pi} -BEC by NA44 and STAR Collaborations by this formula. Results are compared with the previous ones.

Biyajima, Minoru [Department of Physics, Shinshu University, Matsumoto, 390-8621 (Japan); Mizoguchi, Takuya [Toba National College of Maritime Technology, Toba 517-8501 (Japan); Suzuki, Naomichi [Department of Comprehensive Management, Matsumoto University, Matsumoto 390-1295 (Japan)

2006-04-11

318

Lithosphere-asthenosphere structure beneath the United States from joint inversion of body waves, surface waves, and receiver functions  

NASA Astrophysics Data System (ADS)

The Earthscope USArray is providing an unprecedented dataset for seismic imaging. Many studies have generated models in terms of velocity or impedance contrast, but only a few are starting to integrate observations in a joint framework. The most common joint method inverts receiver function delay times with surface wave dispersion curves to image the crust and mantle lithosphere. Advances have also been made by jointly inverting surface wave dispersion observations with body wave relative travel times to image the upper mantle. These joint methods are producing clearer images and are fitting more observations than single dataset methods, however they do have their limitations. The surface wave and receiver function models are limited to the lithosphere while the body wave and surface wave models are inherently smooth which blurs the layered earth structure. By jointly inverting all three datasets we are able to image structure from the surface through the mantle transition zone under the Transportable Array footprint through July 2011. The stable North American craton is imaged at the eastern edge of the model as a thick high velocity body. The western portion of the model is largely slow through the thin lithosphere and upper asthenosphere relative to the craton. Within the asthenosphere, a 'slab graveyard' is imaged where broken fragments of Farallon slab reside. The Yellowstone anomaly rises amongst these slab pieces from the lower mantle to near the surface exerting control over local seismicity and topography. The Colorado Plateau shows signs of weakening of the lithospheric root resulting in removal by dripping. As a whole, the DNA11 model shows the mantle is far from a simple homogeneous medium.

Porritt, R. W.; Allen, R. M.; Pollitz, F. F.; Hung, S.; Obrebski, M. J.

2011-12-01

319

Influence of coastal vegetation on the 2004 tsunami wave impact in west Aceh  

PubMed Central

In a tsunami event human casualties and infrastructure damage are determined predominantly by seaquake intensity and offshore properties. On land, wave energy is attenuated by gravitation (elevation) and friction (land cover). Tree belts have been promoted as “bioshields” against wave impact. However, given the lack of quantitative evidence of their performance in such extreme events, tree belts have been criticized for creating a false sense of security. This study used 180 transects perpendicular to over 100 km on the west coast of Aceh, Indonesia to analyze the influence of coastal vegetation, particularly cultivated trees, on the impact of the 2004 tsunami. Satellite imagery; land cover maps; land use characteristics; stem diameter, height, and planting density; and a literature review were used to develop a land cover roughness coefficient accounting for the resistance offered by different land uses to the wave advance. Applying a spatial generalized linear mixed model, we found that while distance to coast was the dominant determinant of impact (casualties and infrastructure damage), the existing coastal vegetation in front of settlements also significantly reduced casualties by an average of 5%. In contrast, dense vegetation behind villages endangered human lives and increased structural damage. Debris carried by the backwash may have contributed to these dissimilar effects of land cover. For sustainable and effective coastal risk management, location of settlements is essential, while the protective potential of coastal vegetation, as determined by its spatial arrangement, should be regarded as an important livelihood provider rather than just as a bioshield. PMID:22065751

Laso Bayas, Juan Carlos; Marohn, Carsten; Dercon, Gerd; Dewi, Sonya; Piepho, Hans Peter; Joshi, Laxman; van Noordwijk, Meine; Cadisch, Georg

2011-01-01

320

Influence of coastal vegetation on the 2004 tsunami wave impact in west Aceh.  

PubMed

In a tsunami event human casualties and infrastructure damage are determined predominantly by seaquake intensity and offshore properties. On land, wave energy is attenuated by gravitation (elevation) and friction (land cover). Tree belts have been promoted as "bioshields" against wave impact. However, given the lack of quantitative evidence of their performance in such extreme events, tree belts have been criticized for creating a false sense of security. This study used 180 transects perpendicular to over 100 km on the west coast of Aceh, Indonesia to analyze the influence of coastal vegetation, particularly cultivated trees, on the impact of the 2004 tsunami. Satellite imagery; land cover maps; land use characteristics; stem diameter, height, and planting density; and a literature review were used to develop a land cover roughness coefficient accounting for the resistance offered by different land uses to the wave advance. Applying a spatial generalized linear mixed model, we found that while distance to coast was the dominant determinant of impact (casualties and infrastructure damage), the existing coastal vegetation in front of settlements also significantly reduced casualties by an average of 5%. In contrast, dense vegetation behind villages endangered human lives and increased structural damage. Debris carried by the backwash may have contributed to these dissimilar effects of land cover. For sustainable and effective coastal risk management, location of settlements is essential, while the protective potential of coastal vegetation, as determined by its spatial arrangement, should be regarded as an important livelihood provider rather than just as a bioshield. PMID:22065751

Laso Bayas, Juan Carlos; Marohn, Carsten; Dercon, Gerd; Dewi, Sonya; Piepho, Hans Peter; Joshi, Laxman; van Noordwijk, Meine; Cadisch, Georg

2011-11-15

321

AN EXPERIMENTAL STUDY OF SHOCK WAVES RESULTING FROM THE IMPACT OF HIGH VELOCITY MISSILES ON ANIMAL TISSUES  

PubMed Central

The spark shadowgram method of studying shock waves is described. It has been used to investigate the properties of such waves produced by the impact of a high velocity missile on the surface of water. The method can be adapted for study of behavior of shock waves in tissue by placing the tissue on a water surface or immersing it in water. Spark shadowgrams then reveal waves passing from tissue to water or reflected from tissue surfaces. Reflection and transmission of shock waves from muscle, liver, stomach, and intestinal wall are compared with reflection from non-living surfaces such as gelatin gel, steel, plexiglas, cork, and air. Because of its heterogeneous structure, waves transmitted by tissue are dispersed and appear as a series of wavelets. When the accoustical impedance (density x wave velocity) of a medium is less than that in which the wave is moving, reflection will occur with inversion of the wave; i.e., a high pressure wave will become a low pressure wave. This inversion occurs at an air surface and is illustrated by shadowgrams of reflection from stomach wall, from a segment of colon filled with gas, and from air-filled rubber balloons. Bone (human skull and beef ribs) shows good reflection and some transmission of shock waves. When steel is directly hit by a missile, clearly visible elastic waves pass from metal to water, but a similar direct hit on bone does not result in elastic waves strong enough to be detected by a spark shadowgram. PMID:19871617

Harvey, E. Newton; McMillen, J. Howard

1947-01-01

322

Multicriteria analysis to evaluate wave energy converters based on their environmental impact: an Italian case study  

NASA Astrophysics Data System (ADS)

The exploitation of renewable energy resources is fast becoming a key objective in many countries. Countries with coastlines have particularly valuable renewable energy resources in the form of tides, currents, waves and offshore wind. Due to the visual impact of siting large numbers of energy generating devices (eg. wind turbines) in terrestrial landscapes, considerable attention is now being directed towards coastal waters. Due to their environmental sensitivity, the selection of the most adequate location for these systems is a critical factor. Multi-criteria analysis allows to consider a wide variety of key characteristics (e.g. water depth, distance to shore, distance to the electric grid in land, geology, environmental impact) that may be converted into a numerical index of suitability for different WEC devices to different locations. So identifying the best alternative between an offshore or a onshore device may be specifically treated as a multicriteria problem. Special enphasisi should be given in the multicriteria analysis to the environmental impact issues. The wave energy prospective in the Italian seas is relatively low if compared to the other European countries faced to the ocean. Based on the wave climate, the Alghero site, (NW Sardinia, Italy) is one of the most interesting sites for the wave energy perspective (about 10 kW/m). Alghero site is characterized by a high level of marine biodiversity. In 2002 the area northern to Alghero harbour (Capo Caccia-Isola Piana) was established a Marine Protected Area (MPA). It could be discussed for this site how to choose between the onshore/offshore WEC alternative. An offshore device like Wave Dragon (http://www.wavedragon.net/) installed at -65m depth (width=300m and length=170 m) may approximately produce about 3.6 GWh/y with a total cost of about 9,000,000 €. On the other hand, an onshore device like SSG (http://waveenergy.no/), employed as crown wall for a vertical breakwater to enlarge the present harbour protection, and installed at -10m depth (length=300 m) may produce about 2.7 GWh/y with a total costs of about 12,000,000 €, where only the 50% of the amount are the costs of the SSG device. Obviously the environmental impact of the two solutions is quite different. Aim of this study is to provide a multicriteria decision support framework to evaluate the best WEC typology and location in the perspective of the environmental cost-benefit analysis. The general environmental aspects generated by wave power projects will be described. Colonisation patterns and biofouling will be discussed with particular reference to changes of the seabed and alterations due to new substrates. In addition, impacts for fish, fishery and marine mammals will be also considered. We suggest that wave power projects should be evaluated also on the basis of their environmental impacts in the perspective of the Strategic Environmental Assessment (SEA) analysis, as implemented by the European Commission (SEA Directive 2001/42/EC). The early incorporation of the environmental aspects involved in the evaluation of wave power projects will give the opportunity for early mitigations or design modifications, most likely making wave projects more acceptable in the long run and more suitable for the marine environment.

Azzellino, Arianna; Contestabile, Pasquale; Lanfredi, Caterina; Vicinanza, Diego

2010-05-01

323

Modifying Measures Based on Differential Item Functioning (DIF) Impact Analyses  

PubMed Central

Objectives Measure modification can impact comparability of scores across groups and settings. Changes in items can affect the percent admitting to a symptom. Methods Using item response theory (IRT) methods, well-calibrated items can be used interchangeably, and the exact same item does not have to be administered to each respondent, theoretically permitting wider latitude in terms of modification. Results Recommendations regarding modifications vary, depending on the use of the measure. In the context of research, adjustments can be made at the analytic level by freeing and fixing parameters based on findings of differential item functioning (DIF). The consequences of DIF for clinical decision making depend on whether or not the patient’s performance level approaches the scale decision cutpoint. High-stakes testing may require item removal or separate calibrations to ensure accurate assessment. Discussion Guidelines for modification based on DIF analyses and illustrations of the impact of adjustments are presented. PMID:22422759

Teresi, Jeanne A.; Ramirez, Mildred; Jones, Richard N.; Choi, Seung; Crane, Paul K.

2014-01-01

324

9 SCIENTIFIC HIGHLIGHT OF THE MONTH: Calculating Scattering Matrices by Wave Function Matching Calculating Scattering Matrices by Wave Function Matching  

Microsoft Academic Search

As devices are reduced in size, interfaces start to dominate electrical transport making it essential to be able to describe reliably how they transmit and reflect electrons. Wave func- tion matching (WFM) is a transparent technique for calculating transmission and reflection matrices suitable for any Hamiltonian that can be represented in tight-binding form. A first- principles Kohn-Sham Hamiltonian represented on

G. Brocks; V. M. Karpan; P. J. Kelly; P. A. Khomyakov; I. Marushchenko; A. Starikov; M. Talanana; I. Turek; K. Xia; P. X. Xu; M. Zwierzycki; G. E. W. Bauer

325

Impacts of a Convective Gravity-Wave Drag Parameterization in the Middle Atmosphere Circulations  

NASA Astrophysics Data System (ADS)

Impacts of a convectively generated gravity-wave drag (CGWD) parameterization in the middle atmosphere circulations are investigated using two climate simulation results by Whole Atmosphere Community Climate Model (WACCM) and Met Office Unified Model (MetUM), focusing on the southern hemisphere (SH) winter stratosphere and the quasi-biennial oscillation (QBO) in the tropical stratosphere, respectively. The CGWD parameterization used in the two models is developed by Choi and Chun that takes into account spatiotemporal variation of source-level (cloud top) momentum flux spectrum. In WACCM, cumulus convection is strong in the storm track of the SH winter extratropics as well as in the tropics, and thus convective gravity waves provide substantial wave drag in the SH winter stratosphere. The temperature and wind biases in the SH winter stratosphere of WACCM in the July climatology are significantly alleviated by including the CGWD parameterization. The reduction in the wind biases is due to directly the addition of GWDC in the SH midlatitudes and indirectly the enhanced resolved wave drag in response to GWDC. The reduction of the cold temperature is due to the increased downwelling in the SH winter polar region, which stems from an increased poleward motion due to the enhanced wave drag in the midlatitudes. In MetUM, QBO is simulated successfully with the CGWD parameterization in addition to an existing background GWD scheme. The convective gravity-wave momentum flux has a broad wave spectrum that is explicitly determined by the convective sources. Compared to the experiment without the CGWD parameterization, including the CGWD parameterization results in a greater variability in the duration of each phase of the QBO, which is closer to observed. Including the CGWD parameterization also strengthens the annual cycle of zonal wind and it allows for stronger modulation of the semi-annual oscillation.

Chun, Hye-Yeong; Kim, Young-Ha; Choi, Hyun-Joo

326

The 2006 California Heat Wave: Impacts on Hospitalizations and Emergency Department Visits  

PubMed Central

Background Climate models project that heat waves will increase in frequency and severity. Despite many studies of mortality from heat waves, few studies have examined morbidity. Objectives In this study we investigated whether any age or race/ethnicity groups experienced increased hospitalizations and emergency department (ED) visits overall or for selected illnesses during the 2006 California heat wave. Methods We aggregated county-level hospitalizations and ED visits for all causes and for 10 cause groups into six geographic regions of California. We calculated excess morbidity and rate ratios (RRs) during the heat wave (15 July to 1 August 2006) and compared these data with those of a reference period (8–14 July and 12–22 August 2006). Results During the heat wave, 16,166 excess ED visits and 1,182 excess hospitalizations occurred statewide. ED visits for heat-related causes increased across the state [RR = 6.30; 95% confidence interval (CI), 5.67–7.01], especially in the Central Coast region, which includes San Francisco. Children (0–4 years of age) and the elderly (? 65 years of age) were at greatest risk. ED visits also showed significant increases for acute renal failure, cardiovascular diseases, diabetes, electrolyte imbalance, and nephritis. We observed significantly elevated RRs for hospitalizations for heat-related illnesses (RR = 10.15; 95% CI, 7.79–13.43), acute renal failure, electrolyte imbalance, and nephritis. Conclusions The 2006 California heat wave had a substantial effect on morbidity, including regions with relatively modest temperatures. This suggests that population acclimatization and adaptive capacity influenced risk. By better understanding these impacts and population vulnerabilities, local communities can improve heat wave preparedness to cope with a globally warming future. PMID:19165388

Knowlton, Kim; Rotkin-Ellman, Miriam; King, Galatea; Margolis, Helene G.; Smith, Daniel; Solomon, Gina; Trent, Roger; English, Paul

2009-01-01

327

Modelling rock-avalanche induced impact waves: Sensitivity of the model chains to model parameters  

NASA Astrophysics Data System (ADS)

New lakes are forming in high-mountain areas all over the world due to glacier recession. Often they will be located below steep, destabilized flanks and are therefore exposed to impacts from rock-/ice-avalanches. Several events worldwide are known, where an outburst flood has been triggered by such an impact. In regions such as in the European Alps or in the Cordillera Blanca in Peru, where valley bottoms are densely populated, these far-travelling, high-magnitude events can result in major disasters. Usually natural hazards are assessed as single hazardous processes, for the above mentioned reasons, however, development of assessment and reproduction methods of the hazardous process chain for the purpose of hazard map generation have to be brought forward. A combination of physical process models have already been suggested and illustrated by means of lake outburst in the Cordillera Blanca, Peru, where on April 11th 2010 an ice-avalanche of approx. 300'000m3 triggered an impact wave, which overtopped the 22m freeboard of the rock-dam for 5 meters and caused and outburst flood which travelled 23 km to the city of Carhuaz. We here present a study, where we assessed the sensitivity of the model chain from ice-avalanche and impact wave to single parameters considering rock-/ice-avalanche modeling by RAMMS and impact wave modeling by IBER. Assumptions on the initial rock-/ice-avalanche volume, calibration of the friction parameters in RAMMS and assumptions on erosion considered in RAMMS were parameters tested regarding their influence on overtopping parameters that are crucial for outburst flood modeling. Further the transformation of the RAMMS-output (flow height and flow velocities on the shoreline of the lake) into an inflow-hydrograph for IBER was also considered a possible source of uncertainties. Overtopping time, volume, and wave height as much as mean and maximum discharge were considered decisive parameters for the outburst flood modeling and were therewith assumed dependent values. The resulting 54 runs were evaluated by an ANOVA-analysis for each dependent variable. Results show, that the model chain is able to correctly reproduce the 5m-overtopping wave. Further the dependency from the input parameters could be assessed for every dependent variable. It was e.g. shown, that RAMMS-calibration has the strongest influence on all variations, it is more crucial then the uncertainties introduced by assumptions on the initial rock-avalanche volume. The study shows, that from a hazard-assessment point of view, combinations of model chains are acceptable and permissible.

Schaub, Yvonne; Huggel, Christian

2014-05-01

328

Impact Of Coral Structures On Wave Directional Spreading Across A Shallow Reef Flat - Lizard Island, Northern Great Barrier Reef  

NASA Astrophysics Data System (ADS)

Coral reef hydrodynamics operate at several and overlapping spatial-temporal scales. Waves have the most important forcing function on shallow (< 5 m) reefs as they drive most ecological and biogeochemical processes by exerting direct physical stress, directly mixing water (temperature and nutrients) and transporting sediments, nutrients and plankton. Reef flats are very effective at dissipating wave energy and providing an important ecosystem service by protecting highly valued shorelines. The effectiveness of reef flats to dissipate wave energy is related to the extreme hydraulic roughness of the benthos and substrate composition. Hydraulic roughness is usually obtained empirically from frictional-dissipation calculations, as detailed field measurements of bottom roughness (e.g. chain-method or profile gauges) is a very labour and time-consuming task. In this study we measured the impact of coral structures on wave directional spreading. Field data was collected during October 2012 across a reef flat on Lizard Island, northern Great Barrier Reef. Wave surface levels were measured using an array of self-logging pressure sensors. A rapid in situ close-range photogrammetric method was used to create a high-resolution (0.5 cm) image mosaic and digital elevation model. Individual coral heads were extracted from these datasets using geo-morphometric and object-based image analysis techniques. Wave propagation was modelled using a modified version of the SWAN model which includes the measured coral structures in 2m by 1m cells across the reef. The approach followed a cylinder drag approach, neglecting skin friction and inertial components. Testing against field data included bed skin friction. Our results show, for the first time, how the variability of the reef benthos structures affects wave dissipation across a shallow reef flat. This has important implications globally for coral reefs, due to the large extent of their area occupied by reef flats, particularly, as global-scale degradation in coral reef health is causing a lowering of reef carbonate production that might lead to a decrease in reef structure and roughness.

Leon, J. X.; Baldock, T.; Callaghan, D. P.; Hoegh-guldberg, O.; Mumby, P.; Phinn, S. R.; Roelfsema, C. M.; Saunders, M. I.

2013-12-01

329

Shock-wave-induced fracturing of calcareous nannofossils from the Chesapeake Bay impact crater  

USGS Publications Warehouse

Fractured calcareous nannofossils of the genus Discoaster from synimpact sediments within the Chesapeake Bay impact crater demonstrate that other petrographic shock indicators exist for the cratering process in addition to quartz minerals. Evidence for shock-induced taphonomy includes marginal fracturing of rosette-shaped Discoaster species into pentagonal shapes and pressure- and temperature-induced dissolution of ray tips and edges of discoasters. Rotational deformation of individual crystallites may be the mechanism that produces the fracture pattern. Shock-wave-fractured calcareous nannofossils were recovered from synimpact matrix material representing tsunami or resurge sedimentation that followed impact. Samples taken from cohesive clasts within the crater rubble show no evidence of shock-induced fracturing. The data presented here support growing evidence that microfossils can be used to determine the intensity and timing of wet-impact cratering.

Self-Trail J.M.

2003-01-01

330

Shoreline changes and high-energy wave impacts at the leeward coast of Bonaire (Netherlands Antilles)  

NASA Astrophysics Data System (ADS)

Supralittoral coarse-clast deposits along the shores of Bonaire (Netherlands Antilles) as well as increased hurricane frequency during the past decade testify to the major hazard of high-energy wave impacts in the southern Caribbean. Since deducing certain events from the subaerial coarse-clast record involves major uncertainties and historical reports are restricted to the past 500 years, we use a new set of vibracore and push core data (i) to contribute to a more reliable Holocene history of regional extreme-wave events and (ii) to evaluate their impact on shoreline evolution. Multi-proxy palaeoenvironmental analyses (XRF, XRD, grain size distribution, carbonate, LOI, microfossils) were carried out using nearshore sedimentary archives from the sheltered western (leeward) side of Bonaire and its small neighbour Klein Bonaire. In combination with 14C-AMS age estimates the stratigraphy reflects a long-term coastal evolution controlled by relative sea level rise, longshore sediment transport, and short-term morphodynamic impulses by extreme wave action, all three of which may have significantly influenced the development of polyhaline lagoons and the demise of mangrove populations. Extreme wave events may be categorized into major episodic incidents (c. 3.6 ka [?] BP; 3.2-3.0 ka BP; 2.0-1.8 ka BP; post-1.3 ka [?] BP), which may correspond to tsunamis and periodic events recurring on the order of decades to centuries, which we interpret as severe tropical cyclones. Extreme wave events seem to control to a certain extent the formation of coastal ridges on Bonaire and, thus, to cause abrupt shifts in the long-term morphodynamic and ecological boundary conditions of the circumlittoral inland bays.

Engel, Max; Brückner, Helmut; Messenzehl, Karoline; Frenzel, Peter; May, Simon Matthias; Scheffers, Anja; Scheffers, Sander; Wennrich, Volker; Kelletat, Dieter

2012-10-01

331

Remarks on the Wave Function of the Universe in the Dilaton Cosmology  

E-print Network

Motivated by previous works, we study semi-classical cosmological solutions and the wave function of the Wheeler-DeWitt equation in the Bose-Parker-Peleg model. We obtain the wave function of the universe satisfying the suitable boundary condition of the redefined fields, which has not been considered in previous works. For some limiting cases, the Wheeler-DeWitt equation is reduced to the Liouville equation with a boundary, and its solution can be described by well-known functions. The consistent requirement of the boundary condition is related to the avoidance of the curvature singularity.

Wontae Kim; Edwin J. Son; Myung Seok Yoon

2006-07-27

332

Direct Fragmentation of Quarkonia Including Fermi Motion Using Light-cone Wave Function  

E-print Network

We investigate the effect of Fermi motion on the direct fragmentation of the $J/\\psi$ and $\\Upsilon$ states employing a light-cone wave function. Consistent with such a wave function we set up the kinematics of a heavy quark fragmenting into a quarkonia such that the Fermi motion of the constituents split into longitudinal as well as transverse direction and thus calculate the fragmentation functions for these states. In the framework of our investigation, we estimate that the fragmentation probabilities of $J/\\psi$ and $\\Upsilon$ may increase at least up to 14 percent when including this degree of freedom.

M. A. Gomshi Nobary; B. Javadi

2006-06-12

333

Transient difference solutions of the inhomogeneous wave equation: Simulation of the Green's function  

NASA Technical Reports Server (NTRS)

A time-dependent finite difference formulation to the inhomogeneous wave equation is derived for plane wave propagation with harmonic noise sources. The difference equation and boundary conditions are developed along with the techniques to simulate the Dirac delta function associated with a concentrated noise source. Example calculations are presented for the Green's function and distributed noise sources. For the example considered, the desired Fourier transformed acoustic pressures are determined from the transient pressures by use of a ramping function and an integration technique, both of which eliminates the nonharmonic pressure associated with the initial transient.

Baumeiste, K. J.

1983-01-01

334

On the relationship between the Karhunen-Loeve transform and the prolate spheroidal wave functions  

Microsoft Academic Search

We find a close relationship between the discrete Karhunen-Loeve transform (KLT) and the discrete prolate spheroidal wave functions (DPSWF). We show that the DPSWF form a natural basis for an expansion of the eigenfunctions of the KLT in the frequency domain, and then determine more general conditions that any set of functions must obey to be a valid basis. We

Craig L. Fancourt; Jose C. Principe

2000-01-01

335

Basis of symmetric polynomials for many-boson light-front wave functions  

NASA Astrophysics Data System (ADS)

We provide an algorithm for the construction of orthonormal multivariate polynomials that are symmetric with respect to the interchange of any two coordinates on the unit hypercube and are constrained to the hyperplane where the sum of the coordinates is one. These polynomials form a basis for the expansion of bosonic light-front momentum-space wave functions, as functions of longitudinal momentum, where momentum conservation guarantees that the fractions are on the interval [0 ,1 ] and sum to one. This generalizes earlier work on three-boson wave functions to wave functions for arbitrarily many identical bosons. A simple application in two-dimensional ?4 theory illustrates the use of these polynomials.

Chabysheva, Sophia S.; Hiller, John R.

2014-12-01

336

Basis of symmetric polynomials for many-boson light-front wave functions.  

PubMed

We provide an algorithm for the construction of orthonormal multivariate polynomials that are symmetric with respect to the interchange of any two coordinates on the unit hypercube and are constrained to the hyperplane where the sum of the coordinates is one. These polynomials form a basis for the expansion of bosonic light-front momentum-space wave functions, as functions of longitudinal momentum, where momentum conservation guarantees that the fractions are on the interval [0,1] and sum to one. This generalizes earlier work on three-boson wave functions to wave functions for arbitrarily many identical bosons. A simple application in two-dimensional ?^{4} theory illustrates the use of these polynomials. PMID:25615225

Chabysheva, Sophia S; Hiller, John R

2014-12-01

337

Wave Functions for Quantum Black Hole Formation in Scalar Field Collapse  

E-print Network

We study quantum mechanically the self-similar black hole formation by collapsing scalar field and find the wave functions that give the correct semiclassical limit. In contrast to classical theory, the wave functions for the black hole formation even in the supercritical case have not only incoming flux but also outgoing flux. From this result we compute the rate for the black hole formation. In the subcritical case our result agrees with the semiclassical tunneling rate. Furthermore, we show how to recover the classical evolution of black hole formation from the wave function by defining the Hamilton-Jacobi characteristic function as $W = \\hbar {\\rm Im} \\ln \\psi$. We find that the quantum corrected apparent horizon deviates from the classical value only slightly without any qualitative change even in the critical case.

Dongsu Bak; Sang Pyo Kim; Sung Ku Kim; Kwang-Sup Soh; Jae Hyung Yee

1999-10-05

338

Microscopic electronic wave function and interactions between quasiparticles in empirical tight-binding theory  

NASA Astrophysics Data System (ADS)

A procedure to obtain single-electron wave functions within the tight-binding formalism is proposed. It is based on linear combinations of Slater-type orbitals whose screening coefficients are extracted from the optical matrix elements of the tight-binding Hamiltonian. Bloch functions obtained for zinc-blende semiconductors in the extended-basis s p d s* tight-binding model demonstrate very good agreement with first-principles wave functions. We apply this method to the calculation of the electron-hole exchange interaction, and obtain the dispersion of excitonic fine structure in bulk GaAs. Beyond semiconductor nanostructures, this work is a fundamental step toward modeling many-body effects from post-processing single-particle wave functions within the tight-binding theory.

Benchamekh, R.; Raouafi, F.; Even, J.; Ben Cheikh Larbi, F.; Voisin, P.; Jancu, J.-M.

2015-01-01

339

The impact of soil degradation on soil functioning in Europe  

NASA Astrophysics Data System (ADS)

The European Commission has presented in September 2006 its Thematic Strategy for Soil Protection.The Thematic Strategy for Soil Protection consists of a Communication from the Commission to the other European Institutions, a proposal for a framework Directive (a European law), and an Impact Assessment. The Communication (COM(2006) 231) sets the frame. It defines the relevant soil functions for Europe and identifies the major threats. It explains why further action is needed to ensure a high level of soil protection, sets the overall objective of the Strategy and explains what kind of measures must be taken. It establishes a ten-year work program for the European Commission. The proposal for a framework Directive (COM(2006) 232) sets out common principles for protecting soils across the EU. Within this common framework, the EU Member States will be in a position to decide how best to protect soil and how use it in a sustainable way on their own territory. The Impact Assessment (SEC (2006) 1165 and SEC(2006) 620) contains an analysis of the economic, social and environmental impacts of the different options that were considered in the preparatory phase of the strategy and of the measures finally retained by the Commission. Since 2006 a large amount of new evidence has allowed to further document the extensive negative impacts of soil degradation on soil functioning in Europe. Extensive soil erosion, combined with a constant loss of soil organic carbon, have raised attention to the important role soils are playing within the climate change related processes. Other important processes are related to the loss of soil biodiversity, extensive soil sealing by housing and infrastructure, local and diffuse contamination by agricultural and industrial sources, compaction due to unsustainable agricultural practices and salinization by unsustainable irrigation practices. The extended impact assessment by the European Commission has attempted to quantify in monetary terms the actual economic impact of soil degradation in Europe.The total costs of soil degradation that could be assessed for erosion, organic matter decline, salinisation, landslides and contamination on the basis of available data, would be up to €38 billion annually for EU25. These estimates are necessarily wide ranging due to the lack of sufficient quantitative and qualitative data. Future research activities will have to address, in multidisciplinary teams, the social and economic aspects of soil degradation in Europe, in order to come up with more reliable estimates of the economic impact of soil degradation. A more reliable and updated system of indicators needs to be developed in order to cover the full cycle of the Driving forces-Pressures-State-Impact-Response (DPSIR) framework. Recent developments towards a new soil monitoring system for Europe will be presented as well as some of the recent outputs of the European Soil Data Centre (ESDAC).

Montanarella, Luca

2010-05-01

340

Functionally” Univentricular Hearts: Impact of Pre-Natal Diagnosis  

PubMed Central

Within the last few decades the pre-natal echocardiographic diagnosis of congenital heart defects has made substantial progresses, particularly for the identification of complex malformation. “Functionally” univentricular hearts categorize a huge variety of heart malformations. Since no one of the patients with these congenital heart defects can ever undergo a bi-ventricular type of repair, early recognition and decision-making from the neonatal period are required in order to allow for appropriate multiple-step diagnostic and treatment procedures, either of interventional cardiology and/or surgery, on the pathway of “univentricular” heart. In the literature strong disagreements exist about the potential impact of the pre-natal diagnosis on the early and late outcomes of complex congenital heart defects. This review of the recent reports has been undertaken to better understand the impact of pre-natal diagnosis in “functionally” univentricular hearts taking into consideration the following topics: pre-natal screening, outcomes and survival, general morbidity, neurologic and developmental consequences, pregnancy management and delivery planning, resources utilization and costs/benefits issues, ethical implications, parents counseling, and interruption of pregnancy versus treatment. PMID:25774365

Corno, Antonio Francesco

2015-01-01

341

Beyond receiver functions: Passive source reverse time migration and inverse scattering of converted waves  

NASA Astrophysics Data System (ADS)

We present a wave equation prestack depth migration to image crust and mantle structures using multi-component earthquake data recorded at dense seismograph arrays. Transmitted P and S waves recorded on the surface are back propagated using an elastic wave equation solver. The wave modes are separated after the reverse-time continuation of the wavefield from the surface, and subjected to a (cross-correlation type) imaging condition forming an inverse scattering transform. Reverse time migration (RTM) does not make assumptions about the presence or properties of interfaces - notably, it does not assume that interfaces are (locally) horizontal. With synthetic experiments, and different background models, we show that passive source RTM can reconstruct dipping and vertically offset interfaces even in the presence of complex wave phenomena (such as caustics and point diffraction) and that its performance is superior to traditional receiver function analysis, e.g., common conversion point (CCP) stacking, in complex geological environments.

Shang, Xuefeng; de Hoop, Maarten V.; van der Hilst, Robert D.

2012-08-01

342

Climate change impact on North Sea wave conditions: a consistent analysis of ten projections  

NASA Astrophysics Data System (ADS)

Long-term changes in the mean and extreme wind wave conditions as they may occur in the course of anthropogenic climate change can influence and endanger human coastal and offshore activities. A set of ten wave climate projections derived from time slice and transient simulations of future conditions is analyzed to estimate the possible impact of anthropogenic climate change on mean and extreme wave conditions in the North Sea. This set includes different combinations of IPCC SRES emission scenarios (A2, B2, A1B, and B1), global and regional models, and initial states. A consistent approach is used to provide a more robust assessment of expected changes and uncertainties. While the spatial patterns and the magnitude of the climate change signals vary, some robust features among the ten projections emerge: mean and severe wave heights tend to increase in the eastern parts of the North Sea towards the end of the twenty-first century in nine to ten projections, but the magnitude of the increase in extreme waves varies in the order of decimeters between these projections. For the western parts of the North Sea more than half of the projections suggest a decrease in mean and extreme wave heights. Comparing the different sources of uncertainties due to models, scenarios, and initial conditions, it can be inferred that the influence of the emission scenario on the climate change signal seems to be less important. Furthermore, the transient projections show strong multi-decadal fluctuations, and changes towards the end of the twenty-first century might partly be associated with internal variability rather than with systematic changes.

Grabemann, Iris; Groll, Nikolaus; Möller, Jens; Weisse, Ralf

2015-02-01

343

Combined impacts of global warming and pollution: impacts on food web structure and ecosystem function.  

NASA Astrophysics Data System (ADS)

Effects of global species loss on ecosystem function have traditionally been extrapolated from studies which investigate the effect of random species loss or addition. Real species loss is highly patterned and clumped according to trophic position, taxonomic relatedness and interconnectedness with the remainder of the food web. Using pond microcosms, I evoked a realistic pattern of species loss using toxins and warming. Species loss was predictably highly patterned. Influences on ecosystem functions ranged from simple and linear in the case of algal productivity, through to complex and step-like in the case of bacterial decomposition. Impacts on algal productivity were mediated by effects on the rate of grazing by invertebrates. There is strong evidence from the bacterial decomposition results of an `insurance effect' whereby the presence of multiple stressors has a strong, non-additive effect on function. These results clearly show that the traditional ecotoxicological practice of studying effects of single toxins on single species may be highly misleading.

Thompson, R. M.

2005-05-01

344

Predictions for $e^+e^-\\to J/??_c$ with Light-Cone Wave-Functions  

E-print Network

Predictions for $e^+e^-\\to J/\\psi \\eta_c$ from previous studies are made by taking charmonia as a nonrelativistic bound state and by using nonrelativistic QCD(NRQCD) approach. The predicted cross-section is smaller by an order of magnitude than the experimentally observed. We study the process by taking charm quark as a light quark and use light-cone wave-functions to parameterize nonperturbative effects related to charmonia. The total cross section of $e^+e^-\\to J/\\psi \\eta_c$ can be predicted, if these wave-functions are known. Motivated by studies of light-cone wave-functions of light hadrons, we make a reasonable assumption of the forms of light-cone wave-functions. With these light-cone wave-functions we can obtain the cross section which is more closer to the experimentally observed than that from NRQCD approach. We also discuss in detail the difference between two approaches.

J. P. Ma; Z. G. Si

2004-07-06

345

Numerical simulation of two-dimensional wave propagation in functionally graded materials  

Microsoft Academic Search

The propagation of stress waves in functionally graded materials (FGMs) is studied numerically by means of the composite wave-propagation algorithm. Two distinct models of FGMs are considered: (i) a multilayered metal–ceramic composite with averaged properties within layers; (ii) randomly embedded ceramic particles in a metal matrix with prescribed volume fraction. The numerical simulation demonstrates the applicability of that algorithm to the modelling

Arkadi Berezovski; Juri Engelbrecht; G. A Maugin

2003-01-01

346

Electron-deuteron tensor polarization and the short range behavior of the deuteron wave function  

Microsoft Academic Search

We investigate to what extent measurements of the polarization of recoil deuterons in electron-deuteron scattering would allow us to determine the short-range behavior of the deuteron wave function. We find that even if such measurements were performed out to q=10 fm-1 with an error of +\\/-10% and in some cases even within +\\/-1%, a considerable variation in the deuteron wave

L. J. Allen; H. Fiedeldey

1979-01-01

347

Asymptotic scattering wave function for three charged particles and astrophysical capture processes  

E-print Network

in all regions Omeganu, where nu = alpha, betaf, gamma............. 38 E.Conclusion........................... 40 IV ASYMPTOTIC BEHAVIOR OF THE THREE-BODY SCAT- TERED WAVE FOR THREE CHARGED PARTICLES * ... 41 A.Introduction.......................... 41 B... radiative capture reac- tion 7Be(p,gamma)8B ..................... 91 C. Triple reaction rate . . . . . . . . . . . . . . . . . . . . . . 94 1. Matrix element of the triple collision and initial and fifnal state wave functions . . . . . . . . . . . . . . 97 2...

Pirlepesov, Fakhriddin

2006-08-16

348

Power and frequency measurements from a uniform backward wave oscillator as a function of length  

SciTech Connect

The authors describe results from an experiment where the number of ripple periods in the slow wave structure of a backward wave oscillator (BWO) is increased. Both microwave power and frequency measurements are made for each shot. For a given cathode voltage and beam current, the microwave peak power and frequency are plotted as a function of BWO length. In previous investigations, the observation of two power maxima as a function of length was explained by the interaction of the electron beam with the forward traveling wave and reflections at the transition from the slow wave structure into the output waveguide. However, recent numerical calculations using the phase dynamics of electron beam and electromagnetic modes suggest that the power maxima are due to the phase relationship between the electron beam density wave and the backward wave. Experiments were performed on the Sinus-6, a relativistic electron beam accelerator. By adjusting the pressure in the Sinus-6 spark gap switch, cathode voltages between 400 kV to 650 kV can be obtained. The experiment was repeated for different sets of beam parameters. In all cases, the magnetic field used for beam transport was longer than the length of the slow wave structure. The experimental results are compared with phase model calculations and PIC code simulations using KARAT and TWOQUICK.

Moreland, L.D.; Roitman, A.M.; Schamiloglu, E.; Pegel, I.V. [Univ. of New Mexico, Albuquerque, NM (United States); Lemke, R.W. [Sandia National Labs., Albuquerque, NM (United States)

1994-12-31

349

Classical mechanics and the propagation of the discontinuities of the quantum wave function  

SciTech Connect

Geometrical optics can be regarded both as the short-wavelength approximation of the propagation of electromagnetic waves, and as the exact way in which propagate the surfaces of discontinuity of the classical electromagnetic field. In this work we translate this last idea to quantum mechanics (both relativistic and nonrelativistic). We find that the surfaces of discontinuity of the wave function propagate exactly following the classical trajectories determined by the Hamilton-Jacobi equation. As an example, we consider the lack of diffraction of abrupt wave fronts.

Luis, Alfredo [Departamento de Optica, Facultad de Ciencias Fisicas, Universidad Complutense, 28040 Madrid (Spain)

2003-02-01

350

Wave Propagation Analysis of Edge Cracked Circular Beams under Impact Force  

PubMed Central

This paper presents responses of an edge circular cantilever beam under the effect of an impact force. The beam is excited by a transverse triangular force impulse modulated by a harmonic motion. The Kelvin–Voigt model for the material of the beam is used. The cracked beam is modelled as an assembly of two sub-beams connected through a massless elastic rotational spring. The considered problem is investigated within the Bernoulli-Euler beam theory by using energy based finite element method. The system of equations of motion is derived by using Lagrange's equations. The obtained system of linear differential equations is reduced to a linear algebraic equation system and solved in the time domain by using Newmark average acceleration method. In the study, the effects of the location of crack, the depth of the crack, on the characteristics of the reflected waves are investigated in detail. Also, the positions of the cracks are calculated by using reflected waves. PMID:24972050

Akba?, ?eref Do?u?can

2014-01-01

351

The wave-function description of the electromagnetic field  

E-print Network

For an arbitrary electromagnetic field, we define a prepotential $S$, which is a complex-valued function of spacetime. The prepotential is a modification of the two scalar potential functions introduced by E. T. Whittaker. The prepotential is Lorentz covariant under a spin half representation. For a moving charge and any observer, we obtain a complex dimensionless scalar. The prepotential is a function of this dimensionless scalar. The prepotential $S$ of an arbitrary electromagnetic field is described as an integral over the charges generating the field. The Faraday vector at each point may be derived from $S$ by a convolution of the differential operator with the alpha matrices of Dirac. Some explicit examples will be calculated. We also present the Maxwell equations for the prepotential.

Yaakov Friedman

2013-04-30

352

Submillimeter Wave Astronomy Satellite observations of comet 9P/Tempel 1 and Deep Impact  

E-print Network

On 4 July 2005 at 5:52 UT the Deep Impact mission successfully completed its goal to hit the nucleus of 9P/Tempel 1 with an impactor, forming a crater on the nucleus and ejecting material into the coma of the comet. NASA's Submillimeter Wave Astronomy Satellite (SWAS) observed the 1(10)-1(01) ortho-water ground-state rotational transition in comet 9P/Tempel 1 before, during, and after the impact. No excess emission from the impact was detected by SWAS and we derive an upper limit of 1.8e7 kg on the water ice evaporated by the impact. However, the water production rate of the comet showed large natural variations of more than a factor of three during the weeks before and after the impact. Episodes of increased activity with Q(H2O)~1e28 molecule/s alternated with periods with low outgassing (Q(H2O)comet rotates. We calculate that appreciable asymmetries of these features could lead to a spin-down or spin-up of the nucleus at observable rates.

F. Bensch; G. J. Melnick; D. A. Neufeld; M. Harwit; R. L. Snell; B. M. Patten; V. Tolls

2006-06-02

353

Kinetic correlation in the final-state wave function in photo-double-ionization of He  

SciTech Connect

We evaluate the triply differential cross section (TDCS) for photo-double-ionization of helium. We use a final continuum wave function which correlates the motion of the three particles, through an expansion in products of two-body Coulomb functions. This function satisfies a set of appropriate physical conditions in the coalescence points, in addition to the correct asymptotic behavior condition. We analyze the effect of this correlation in the TDCS and compare our results with experimental data.

Otranto, S. [CONICET and Centro Atomico Bariloche, 8400 San Carlos de Bariloche, (Argentina); Departamento de Fisica, Universidad Nacional del Sur, 8000 Bahia Blanca, (Argentina); Garibotti, C. R. [CONICET and Centro Atomico Bariloche, 8400 San Carlos de Bariloche, (Argentina)

2003-06-01

354

Nonlinear response function for time-domain and frequency-domain four-wave mixing  

Microsoft Academic Search

A unified theory of time-domain and frequency-domain four-wave mixing processes, which is based on the nonlinear response function R(t 3 , t 2, t), is developed. The response function is expressed in terms of the four-point correlation function of the dipole operator F(r 1 , T2, T3, 4) and is evaluated explicitly for a stochastic model of line broadening that

Shaul Mukamel; Roger F. Loring

1986-01-01

355

The impact of alcohol dependence on social brain function.  

PubMed

The impact of alcoholism (ALC) or alcohol dependence on the neural mechanisms underlying cognitive and affective empathy (i.e. the different routes to understanding other people's minds) in schizophrenic patients and non-schizophrenic subjects is still poorly understood. We therefore aimed at determining the extent to which the ability to infer other people's mental states and underlying neural mechanisms were affected by ALC. We examined 48 men, who suffered either from ALC, schizophrenia, both disorders or none of these disorders, using functional magnetic resonance imaging while performing on a mind reading task that involves both cognitive and affective aspects of empathy. Using voxel-based morphometry, we additionally examined whether between-group differences in functional activity were associated with deficits in brain structural integrity. During mental state attribution, all clinical groups as compared with healthy controls exhibited poor performance as well as reduced right-hemispheric insular function with the highest error rate and insular dysfunction seen in the schizophrenic patients without ALC. Accordingly, both behavioral performance and insular functioning revealed schizophrenia × ALC interaction effects. In addition, schizophrenic patients relative to non-schizophrenic subjects (regardless of ALC) exhibited deficits in structural integrity and task-related recruitment of the left ventrolateral prefrontal cortex (vlPFC). Our data suggest that ALC-related impairment in the ability to infer other people's mental states is limited to insular dysfunction and thus deficits in affective empathy. By contrast, mentalizing in schizophrenia (regardless of ALC) may be associated with insular dysfunction as well as a combination of structural and functional deficits in the left vlPFC. PMID:22340281

Gizewski, Elke R; Müller, Bernhard W; Scherbaum, Norbert; Lieb, Bodo; Forsting, Michael; Wiltfang, Jens; Leygraf, Norbert; Schiffer, Boris

2013-01-01

356

Performance of storm damage functions: a sectoral impact model intercomparison  

NASA Astrophysics Data System (ADS)

Winter storms are the most costly natural hazard for European residential property. We compare four distinct storm damage functions with respect to their forecast accuracy and variability, with particular regard to the most severe winter storms. The analysis focuses on daily loss estimates under differing spatial aggregation, ranging from district to country level. We discuss the broad and heavily skewed distribution of insured losses posing difficulties on both the calibration and the evaluation of damage functions. From theoretical considerations, we provide a synthesis between the frequently discussed cubic damage-wind relationship and recent studies that report much steeper damage functions for European winter storms. The performance of the storm loss models is evaluated for two wind data sources, direct observation by the German Weather Service and ERA Interim reanalysis data. While the choice of wind data indicates little impact for the evaluation of German storm loss, local variability exhibits dependence between model and data choices. Based on our analysis, we favour the application of two probabilistic approaches which fare best in terms of the accuracy of their expected value and overall exhibit the lowest amount of variability.

Prahl, B. F.; Rybski, D.; Burghoff, O.; Kropp, J. P.

2014-09-01

357

Gap Wave Propagation in Functionally Graded Piezoelectric Material Structures  

E-print Network

-space and a piezoceramic plate were investigated in [3]. A new-style material called functionally graded material (FGM) was proposed to solve problems in the thermal-protection systems of a space-plane in 1980s. From then on, FGM has attracted interest of investigators from many kinds of disciplines. Today, FGM can be used

Wang, Ji

358

Love wave propagation in functionally graded piezoelectric material layer  

E-print Network

functionally graded material (FGM) was proposed to solve problems in the thermal- protection systems of aerospace structures in 1980s. Since then, FGM has attracted interest of investigators from many engineering disciplines. Today, FGM can be used not only in thermal-protection systems but also in elec- tronic and many

Wang, Ji

359

Exp-function method for nonlinear wave equations  

Microsoft Academic Search

In this paper, a new method, called Exp-function method, is proposed to seek solitary solutions, periodic solutions and compacton-like solutions of nonlinear differential equations. The modified KdV equation and Dodd–Bullough–Mikhailov equation are chosen to illustrate the effectiveness and convenience of the suggested method.

Ji-Huan He; Xu-Hong Wu

2006-01-01

360

The Impact of Heat Islands on Mortality in Paris during the August 2003 Heat Wave  

PubMed Central

Background: Heat waves have a drastic impact on urban populations, which could increase with climate change. Objectives: We evaluated new indicators of elderly people’s exposure to heat in Paris, from a public health prevention perspective, using satellite thermal images. Methods: We used a time series of 61 images from the satellites of the National Oceanic and Atmospheric Administration’s (NOAA) Advanced Very High Resolution Radiometer (AVHRR) taken from 1 to 13 August 2003 to produce thermal indicators of minimum, maximum, and mean surface temperatures and diurnal temperature amplitude, with different lags between the meteorological data and the health impact. Health data came from a case–control study involving 241 people ? 65 years of age who died in the city of Paris or the nearby suburban area of Val-de-Marne during the August 2003 heat wave, and 241 controls who were matched to cases on age, sex, and residential zone. For each person, we integrated the thermal indicators in a conditional logistic regression model, adjusted for age and other potential confounders. We computed odds ratios (ORs) comparing the 90th and 50th percentiles of the temperature differences between cases and controls for various indicators. Results: Mortality risk was significantly associated with exposure for two indicators: minimum temperatures averaged for 1–13 August [for a 0.41°C increase, OR = 2.17; 95% confidence interval (CI): 1.14, 4.16] and minimum temperature averaged on the day of death and the 6 preceding days (for a 0.51°C increase: OR = 2.24; 95% CI: 1.03, 4.87). Conclusions: Our results support the influence of night temperatures on the health impact of heat waves in urban areas. Urban heat exposure indicators based on satellite imagery have the potential to identify areas with higher risk of death, which could inform intervention decisions by key stakeholders. PMID:21885383

Zeghnoun, Abdelkrim; Dousset, Bénédicte; Bretin, Philippe; Vandentorren, Stéphanie; Giraudet, Emmanuel; Beaudeau, Pascal

2011-01-01

361

Interpreting scattering wave functions in the presence of energy-dependent interactions  

E-print Network

In scattering theory, the squared relative wave function $|\\phi({\\bf q},{\\bf r})|^2$ is often interpreted as a weight, due to final-state interactions, describing the probability enhancement for emission with asymptotic relative momentum $q$. An equivalence relation also links the integral of the squared wave function over all coordinate space to the density of states. This relation, which plays an important role in understanding two-particle correlation phenomenology, is altered for the case where the potential is energy dependent, as is assumed in various forms of reaction theory. Here, the modification to the equivalence relation is derived, and it is shown that the squared wave function should be augmented by a additional factor if it is to represent the emission enhancement for final-state interactions. Examples with relativistic vector interactions, e.g., the Coulomb interaction, are presented.

Scott Pratt

2007-11-09

362

U (1 )×U (1 ) symmetry-protected topological order in Gutzwiller wave functions  

NASA Astrophysics Data System (ADS)

Gutzwiller projection is a way to construct many-body wave functions that could carry topological order or symmetry-protected topological (SPT) order. However, an important issue is to determine whether or not a given Gutzwiller-projected wave function (GWF) carries a nontrivial SPT order, and which SPT order is carried by the wave function. In this paper, we numerically study the SPT order in a spin S =1 GWF on the kagome lattice. Using the standard Monte Carlo method, we directly confirm that the GWF has (1) gapped bulk with short-range correlations, (2) a trivial topological order via a nondegenerate ground state, and zero topological entanglement entropy, (3) a nontrivial U (1 )×U (1 ) SPT order via the Hall conductances of the protecting U (1 )×U (1 ) symmetry, and (4) a symmetry-protected gapless boundary. This represents numerical evidence of continuous symmetry-protected topological order in two-dimensional bosonic lattice systems.

Liu, Zheng-Xin; Mei, Jia-Wei; Ye, Peng; Wen, Xiao-Gang

2014-12-01

363

Quantization of the 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 provides an algebraically consistent way of discretizing the Dirac algebra for general relativity. This paper successfully formulates the Wheeler-DeWitt quantization of the canonical tensor model. Formally one can obtain wave functions of the "universe" by solving the partial differential equations representing the constraints. For the simplest non-trivial case, the unique wave function is exactly and globally obtained. Although this case is far from being realistic, the wave function is physically interesting; locality is favored, and there exists a locus of configurations with features of the beginning of the universe.

Sasakura, Naoki

2014-03-01

364

The No-Boundary Wave Function and the Duration of the Inflationary Period  

E-print Network

For the simplest minisuperspace model based on a homogeneous, isotropic metric and a minimally coupled scalar field we derive analytic expressions for the caustic which separates Euklidean and Minkowskian region and its breakdown value $\\p_*$. This value represents the prediction of the no-boundary wave function for the scalar field at the beginning of inflation. We use our results to search for inflationary models which can render the no-boundary wave function consistent with the requirement of a sufficiently long inflationary period.

A. Lukas

1994-09-07

365

When valence bond wave functions are analyzed through QTAIM: Conceptual incompatibilities in H2  

NASA Astrophysics Data System (ADS)

Hydrogen molecule was chosen, for simplicity, to analyze its valence bond (VB) wave function with the Quantum Theory of Atoms in Molecules (QTAIM). We find that the usual association of its covalent and ionic contributions to individual Lewis structures does not agree with the localization and delocalization indices between both hydrogens defined within the QTAIM framework. Concretely, we analyzed the dependence of both indices with the internuclear distance and with different ionic/covalent relative weightings. The results indicate that QTAIM localization and delocalization indices should not be estimated from interpretations of the VB wave function in terms of the Lewis model.

Ferro-Costas, David; Mosquera, Ricardo A.

2015-01-01

366

Selected new developments in vibrational structure theory: potential construction and vibrational wave function calculations.  

PubMed

This perspective addresses selected recent developments in the theoretical calculation of vibrational spectra, energies, wave functions and properties. The theoretical foundation and recently developed computational protocols for constructing hierarchies of vibrational Hamiltonian operators are reviewed. A many-mode second quantization (SQ) formulation is discussed prior to the discussion of anharmonic wave functions. Emphasis is put on vibrational self-consistent field (VSCF) based methods and in particular vibrational coupled cluster (VCC) theory. Other issues are also reviewed briefly, such as inclusion of thermal effects, response theoretical calculation of spectra, and the difficulty in treating dense spectra. PMID:22491444

Christiansen, Ove

2012-04-10

367

Impact wave monitoring in soil using a dynamic fiber sensor based on stimulated brillouin scattering.  

PubMed

The impact wave response of soil due to a ball drop is monitored on a 30.5 cm by 30.5 cm square soil box using a fiber sensor with dynamic strain sensing capability. The experiments are conducted in real time using a simple one-laser one-modulator configuration with stimulated Brillouin scattering. The embedded BOTDA sensor grid successfully monitored the distribution and evolution of the inner strains of a sand bed during a mass impact on its surface. The measurement of the distributed dynamic strains was possible in several milliseconds and with 1 cm actual location resolution. This paper presents a time-domain signal analysis utilized for determining the dynamic strains in embedded fiber sensor. The results demonstrate the method to be a promising one for detection of subsurface vibration and movement in geotechnical Structure Health Monitoring (SHM). PMID:25856327

Cui, Qingsong; Pamukcu, Sibel; Pervizpour, Mesut

2015-01-01

368

Does Laser Type Impact Myocardial Function Following Transmyocardial Laser Revascularization?  

PubMed Central

Background Transmyocardial laser revascularization (TMR) is currently clinically performed with either a CO2 or Ho:YAG laser for the treatment of severe angina. While both lasers provide symptomatic relief, there are significant differences in the laser–tissue interactions specific to each device that may impact their ability to enhance the perfusion of myocardium and thereby improve contractile function of the ischemic heart. Methods A porcine model of chronic myocardial ischemia was employed. After collecting baseline functional data with cine magnetic resonance imaging (MRI) and dobutamine stress echo (DSE), 14 animals underwent TMR with either a CO2 or Ho:YAG laser. Transmural channels were created with each laser in a distribution of 1/cm2 in the ischemic zone. Six weeks post-treatment repeat MRI as well as DSE were obtained after which the animals were sacrificed. Histology was preformed to characterize the laser–tissue interaction. Results CO2 TMR led to improvement in wall thickening in the ischemic area as seen with cine MRI (40.3% vs. baseline, P < 0.05) and DSE (20.2% increase vs. baseline, P < 0.05). Ho:YAG treated animals had no improvement in wall thickening by MRI (?11.6% vs. baseline, P = .67) and DSE (?16.7% vs. baseline, P = 0.08). Correlative semi-quantitative histology revealed a significantly higher fibrosis index in Ho:YAG treated myocardium versus CO2 (1.81 vs. 0.083, P < 0.05). Conclusions In a side-by-side comparison CO2 TMR resulted in improved function of ischemic myocardium as assessed by MRI and echocardiography. Ho:YAG TMR led to no improvement in regional function likely due to concomitant increase in fibrosis in the lasered area. PMID:21246579

Estvold, Soren K.; Mordini, Frederico; Zhou, Yifu; Yu, Zu X.; Sachdev, Vandana; Arai, Andrew; Horvath, Keith A.

2012-01-01

369

Finasteride-Its Impact on Sexual Function and Prostate Cancer  

PubMed Central

Finasteride, a specific and competitive inhibitor of 5?-reductase enzyme Type 2, inhibits the conversion of testosterone to dihydrotestosterone (DHT). In adults, DHT acts as primary androgen in prostate and hair follicles. The only FDA-approved dermatological indication of finasteride is androgenetic alopecia. But, apprehension regarding sexual dysfunction associated with finasteride deters dermatologists from prescribing the drug and patients from taking the drug for androgenetic alopecia. Testosterone, through its humoral endocrine and local paracrine effects is relevant in central and peripheral modulation of sexual function than locally acting DHT. Several large population-based long-term placebo-controlled studies, using International Index of Erectile Function-5 questionnaire and objective method (Nocturnal Penile Tumescence) to assess the erectile function have demonstrated no clear evidence of the negative effect of finasteride on erectile function. Reduction in ejaculatory volume is the only established causal relationship between finasteride and sexual dysfunction. Though finasteride causes significant reduction in all the semen parameters except sperm morphology, they did not fall below the threshold levels to interfere with fertility. Therefore, the sexual adverse effects associated with finasteride should be viewed in relation to normal prevalence and natural history of erectile dysfunction in the population, age of the patient, other confounding factors and also nocebo effect. The impact of finasteride on the prevention of prostate cancer has been discussed extensively. Finasteride is found to be effective in significantly reducing the incidence of low-grade prostate cancer. But the paradoxical increase in high-grade cancer in the finasteride group has been attributed to increased sensitivity and improved performance of prostate specific antigen levels to detect all grades of prostate cancer. PMID:20300365

Anitha, B; Inamadar, Arun C; Ragunatha, S

2009-01-01

370

Harvesting broadband kinetic impact energy from mechanical triggering/vibration and water waves.  

PubMed

We invented a triboelectric nanogenerator (TENG) that is based on a wavy-structured Cu-Kapton-Cu film sandwiched between two flat nanostructured PTFE films for harvesting energy due to mechanical vibration/impacting/compressing using the triboelectrification effect. This structure design allows the TENG to be self-restorable after impact without the use of extra springs and converts direct impact into lateral sliding, which is proved to be a much more efficient friction mode for energy harvesting. The working mechanism has been elaborated using the capacitor model and finite-element simulation. Vibrational energy from 5 to 500 Hz has been harvested, and the generator's resonance frequency was determined to be ?100 Hz at a broad full width at half-maximum of over 100 Hz, producing an open-circuit voltage of up to 72 V, a short-circuit current of up to 32 ?A, and a peak power density of 0.4 W/m(2). Most importantly, the wavy structure of the TENG can be easily packaged for harvesting the impact energy from water waves, clearly establishing the principle for ocean wave energy harvesting. Considering the advantages of TENGs, such as cost-effectiveness, light weight, and easy scalability, this approach might open the possibility for obtaining green and sustainable energy from the ocean using nanostructured materials. Lastly, different ways of agitating water were studied to trigger the packaged TENG. By analyzing the output signals and their corresponding fast Fourier transform spectra, three ways of agitation were evidently distinguished from each other, demonstrating the potential of the TENG for hydrological analysis. PMID:24964297

Wen, Xiaonan; Yang, Weiqing; Jing, Qingshen; Wang, Zhong Lin

2014-07-22

371

Automated calculation of anharmonic vibrational contributions to first hyperpolarizabilities: Quadratic response functions from vibrational configuration interaction wave functions  

NASA Astrophysics Data System (ADS)

Quadratic response functions are derived and implemented for a vibrational configuration interaction state. Combined electronic and vibrational quadratic response functions are derived using Born-Oppenheimer vibronic product wave functions. Computational tractable expressions are derived for determining the total quadratic response contribution as a sum of contributions involving both electronic and vibrational linear and quadratic response functions. In the general frequency-dependent case this includes a new and more troublesome type of electronic linear response function. Pilot calculations for the FH, H2O, CH2O, and pyrrole molecules demonstrate the importance of vibrational contributions for accurate comparison to experiment and that the vibrational contributions in some cases can be very large. The calculation of transition properties between vibrational states is combined with sum-over-states expressions for analysis purposes. On the basis of this some simple analysis methods are suggested. Also, a preliminary study of the effect of finite lifetimes on quadratic response functions is presented.

Hansen, Mikkel Bo; Christiansen, Ove; Hättig, Christof

2009-10-01

372

Uniform approximation of wave functions with improved semiclassical transformation amplitudes and Gram-Schmidt orthogonalization  

SciTech Connect

Semiclassical transformation theory implies an integral representation for stationary-state wave functions {psi}{sub m}(q) in terms of angle-action variables ({theta},J). It is a particular solution of Schroedinger's time-independent equation when terms of order ({Dirac_h}/2{pi}){sup 2} and higher are omitted, but the preexponential factor A(q,{theta}) in the integrand of this integral representation does not possess the correct dependence on q. The origin of the problem is identified: the standard unitarity condition invoked in semiclassical transformation theory does not fix adequately in A(q,{theta}) a factor which is a function of the action J written in terms of q and {theta}. A prescription for an improved choice of this factor, based on successfully reproducing the leading behavior of wave functions in the vicinity of potential minima, is outlined. Exact evaluation of the modified integral representation via the residue theorem is possible. It yields wave functions which are not, in general, orthogonal. However, closed-form results obtained after Gram-Schmidt orthogonalization bear a striking resemblance to the exact analytical expressions for the stationary-state wave functions of the various potential models considered (namely, a Poeschl-Teller oscillator and the Morse oscillator)

Davis, Edward D. [Department of Physics, Kuwait University, P.O. Box 5969, Safat (Kuwait)

2004-09-01

373

Human adipocyte function is impacted by mechanical cues.  

PubMed

Fibrosis is a hallmark of human white adipose tissue (WAT) during obesity-induced chronic inflammation. The functional impact of increased interstitial fibrosis (peri-adipocyte fibrosis) on adjacent adipocytes remains unknown. Here we developed a novel in vitro 3D culture system in which human adipocytes and decellularized material of adipose tissue (dMAT) from obese subjects are embedded in a peptide hydrogel. When cultured with dMAT, adipocytes showed decreased lipolysis and adipokine secretion and increased expression/production of cytokines (IL-6, G-CSF) and fibrotic mediators (LOXL2 and the matricellular proteins THSB2 and CTGF). Moreover, some alterations including lipolytic activity and fibro-inflammation also occurred when the adipocyte/hydrogel culture was mechanically compressed. Notably, CTGF expression levels correlated with the amount of peri-adipocyte fibrosis in WAT from obese individuals. Moreover, dMAT-dependent CTGF promoter activity, which depends on ?1-integrin/cytoskeleton pathways, was enhanced in the presence of YAP, a mechanosensitive co-activator of TEAD transcription factors. Mutation of TEAD binding sites abolished the dMAT-induced promoter activity. In conclusion, fibrosis may negatively affect human adipocyte function via mechanosensitive molecules, in part stimulated by cell deformation. PMID:24623048

Pellegrinelli, V; Heuvingh, J; du Roure, O; Rouault, C; Devulder, A; Klein, C; Lacasa, M; Clément, E; Lacasa, D; Clément, K

2014-06-01

374

Semiclassical Study of the Wave Vector Dependence of the Interband Impact Ionization Rate in Bulk Silicon  

NASA Technical Reports Server (NTRS)

We present calculations of the interband impact ionization rate calculated using a wave vector dependent (k-dependent) semiclassical formulation of the transition rate. The transition rate is determined using Fermi's golden rule from a two-body screened Coulomb interaction assuming energy and momentum conservation. The transition rate is calculated for the first two conduction bands of silicon by numerically integrating over the full Brillouin zone. The overlap integrals in the expression for the transition rate are determined numerically using a 15 band k-p calculation. It is found that the transition rate depends strongly on the initiating electron wave vector (k vector) and that the transition rate is greatest for electrons originating within the second conduction band than the first conduction band. An ensemble Monte Carlo simulation, which includes the numerically determined ionization transition rate as well as the full details of the first two conduction bands, is used to calculate the total impact ionization rate in bulk silicon. Good agreement with the experimentally determined electron ionization rate data is obtained.

Wang, Yang; Brennan, Kevin F.

1994-01-01

375

An experimental and theoretical investigation of spray characteristics of impinging jets in impact wave regime  

NASA Astrophysics Data System (ADS)

The current study focuses on experimentally and theoretically improving the characterization of the drop size and drop velocity for like-on-like doublet impinging jets. The experimental measurements were made using phase Doppler anemometry (PDA) at jet Weber numbers We j corresponding to the impact wave regime of impinging jet atomization. A more suitable dynamic range was used for PDA measurements compared to the literature, resulting in more accurate experimental measurements for drop diameters and velocities. There is some disagreement in the literature regarding the ability of linear stability analysis to accurately predict drop diameters in the impact wave regime. This work seeks to provide some clarity. It was discovered that the assumed uniform jet velocity profile was a contributing factor for deviation between diameter predictions based on models in the literature and experimental measurements. Analytical expressions that depend on parameters based on the assumed jet velocity profile are presented in this work. Predictions based on the parabolic and 1/7th power law turbulent profiles were considered and show better agreement with the experimental measurements compared to predictions based on the previous models. Experimental mean drop velocity measurements were compared with predictions from a force balance analysis, and it was observed that the assumed jet velocity profile also influences the predicted velocities, with the turbulent profile agreeing best with the experimental mean velocity. It is concluded that the assumed jet velocity profile has a predominant effect on drop diameter and velocity predictions.

Rodrigues, N. S.; Kulkarni, V.; Gao, J.; Chen, J.; Sojka, P. E.

2015-03-01

376

Floating potential perturbations due to micrometeoroid impacts: Theory and application to S/WAVES data  

NASA Astrophysics Data System (ADS)

In situ observation of dust grains from various origins is routinely performed by space missions equipped with radio instruments. These measurements consist in observations of voltage pulses or their spectral signature. It has for long been proposed that one of the mechanisms able to produce these pulses is the collection by the spacecraft of electric charges generated by impact ionization. Here for the first time, a complete theoretical model of how pulses are generated by charge collection is proposed. In the solar wind at 1 AU, the pulses are shown to be shaped by local plasma and photoelectron parameters. However, the situation can be different in hotter or denser plasma environments. We use the data provided by the STEREO/WAVES (S/WAVES) radio instrument onboard the twin STEREO spacecraft to validate our model. We find that the observations indeed strongly support the theory. The proposed model is an important step forward, since it makes it possible to reproduce the shape, timescales, and amplitudes of pulses generated by dust impacts in various space environments. Such a model can be used to infer the dust detection abilities of radio instruments onboard different spacecraft and can help the design of dust detection optimized radio instruments for future missions.

Zaslavsky, A.

2015-02-01

377

Impact of current-wave interaction on storm surge simulation: A case study for Hurricane Bob  

NASA Astrophysics Data System (ADS)

Hurricane Bob moved up the U.S. east coast and crossed over southern New England and the Gulf of Maine [with peak marine winds up to 54 m/s (100 mph)] on 19-20 August 1991, causing significant damage along the coast and shelf. A 3-D fully wave-current-coupled finite-volume community ocean model system was developed and applied to simulate and examine the coastal ocean responses to Hurricane Bob. Results from process study-oriented experiments showed that the impact of wave-current interaction on surge elevation varied in space and time, more significant over the shelf than inside the inner bays. While sea level change along the coast was mainly driven by the water flux controlled by barotropic dynamics and the vertically integrated highest water transports were essentially the same for cases with and without water stratification, the hurricane-induced wave-current interaction could generate strong vertical current shear in the stratified areas, leading to a strong offshore transport near the bottom and vertical turbulent mixing over the continental shelf. Stratification could also result in a significant difference of water currents around islands where the water is not vertically well mixed.

Sun, Yunfang; Chen, Changsheng; Beardsley, Robert C.; Xu, Qichun; Qi, Jianhua; Lin, Huichan

2013-05-01

378

The formation of shatter cones by shock wave interference during impacting  

NASA Astrophysics Data System (ADS)

In this paper we present a new model for the formation of shatter cones. The model follows earlier suggestions that shatter cones are initiated by heterogeneities in the rock, but does not require the participation of an elastic precursor wave: the conical fractures are initiated after the passage of the main plastic compression pulse, not before. Numerical simulations using the hydrocode SALE 2D, enhanced by the Grady-Kipp-Melosh fragmentation model, support the model. The conditions required for the formation of shatter cones are explored numerically and are found to be consistent with the pressure range derived from both explosion experiments and the analysis of shock metamorphic features in impact structures. This model permits us to deduce quantitative information about the shape of the shock wave from the shape and size of the observed shatter cones. Indeed, the occurrence of shatter cones is correlated with the ratio between the width of the compressive pulse and the size of the heterogeneity that initiates the conical fracture. The apical angles of the shatter cones are controlled by the shape of the rarefaction wave.

Baratoux, D.; Melosh, H. J.

2003-11-01

379

Functional Connectivity between Brain Areas Estimated by Analysis of Gamma Waves  

PubMed Central

The goal of this study is to investigate functional connectivity between different brain regions by analyzing the temporal relationship of the maxima of gamma waves recorded in multiple brain areas. Local field potentials were recorded from motor cortex, hippocampus, entorhinal cortex and piriform cortex of rats. Gamma activity was filtered and separated into two bands; high (65–90Hz) and low (30–55Hz) gamma. Maxima for gamma activity waves were detected and functional connectivity between different brain regions was determined using Shannon entropy for perievent histograms for each pair channels. Significant Shannon entropy values were reported as connectivity factors. We defined a connectivity matrix based the connectivity factors between different regions. We found that maxima of low and high frequency gamma occur in strong temporal relationship between some brain areas, indicating the existence of functional connections between these areas. The spatial pattern of functional connections between brain areas was different for slow wave sleep and waking states. However for each behavioral state in the same animal the pattern of functional connections was stable over time within 30 minutes of continuous analysis and over a 5 day period. With the same electrode montage the pattern of functional connectivity varied from one subject to another. Analysis of the temporal relationship of maxima of gamma waves between various brain areas could be a useful tool for investigation of functional connections between these brain areas. This approach could be applied for analysis of functional alterations occurring in these connections during different behavioral tasks and during processes related to learning and memory. The specificity in the connectivity pattern from one subject to another can be explained by the existence of unique functional networks for each subject. PMID:23376499

Kheiri, Farshad; Bragin, Anatol; Engel, Jerome

2013-01-01

380

The seismic response of an aquifer to the propagation of an impact generated shock wave: A possible trigger of the Martian outflow channels?  

NASA Technical Reports Server (NTRS)

Aquifer dilation from shock waves produced by the 8.4 magnitude Alaskan earthquake of 1964 led to water and sediment ejection from the ground up to 400 km away from the earthquake's epicenter. Groundwater disturbances were observed as far away as Perry, Florida (approximately 5500 km), where well water fluctuations with an amplitude of as much as 2.3 m were reported. The martian cratering record provides evidence that the planet has experienced numerous seismic events of a similar, and often much greater, magnitude. Given this fact, and the photogeologic evidence for abundant water in the early crust, the response of a basalt aquifer to the propagation of compressional waves (P-waves) produced by impacts in the 33-1000 km diameter size range were investigated. The resulting one-dimensional changes in effective stress and pore pressure were calculated - as a function of both distance and time - based on the following assumptions: (1) that all of the seismic energy radiated by an impact is transmitted as a single compressional wave; (2) that both the host rock and groundwater are compressible; and (3) that there is no net flow between the water-filled pores.

Leyva, Ivett A.; Clifford, Stephen M.

1993-01-01

381

Operator Dictionaries and Wave Functions in AdS/CFT and dS/CFT  

E-print Network

Dual AdS/CFT correlators can be computed in two ways: differentiate the bulk partition function with respect to boundary conditions, or extrapolate bulk correlation functions to the boundary. These dictionaries were conjectured to be equivalent by Banks, Douglas, Horowitz, and Martinec. We revisit this question at the level of bulk path integrals, showing that agreement in the presence of interactions requires careful treatment of the renormalization of bulk composite operators. By contrast, we emphasize that proposed dS/CFT analogues of the two dictionaries are inequivalent. Next, we show quite generally that the wave function for Euclidean AdS analytically continues to the dS wave function with Euclidean initial conditions. Most of our arguments consider interacting fields on a fixed background, but in a final section we discuss the inclusion of bulk dynamical gravity.

Daniel Harlow; Douglas Stanford

2011-04-21

382

NRQCD Factorization for Twist-2 Light-Cone Wave-Functions of Charmonia  

E-print Network

We show that the twist-2 light-cone wave-functions of eta_c and J/\\psi can be factorized with nonrelativistic QCD(NRQCD) at one-loop level, where the nonperturbative effects are represented by NRQCD matrix elements. The factorization is achieved by expanding the small velocity v, which the c- or \\bar c- quark moves inside a rest quarkonium with. At leading order of v the twist-2 light-cone wave-functions of eta_c and J/\\psi can be factorized as the product of a perturbative function and a NRQCD matrix element. The perturbative function is calculated at one-loop level and free from any soft divergence. Our results can be used for the production of J/\\psi\\eta_c through e^+e^- -annihilation and of a charmonium in B-decays, which are studied in experiment of two B-factories.

J. P. Ma; Z. G. Si

2006-08-20

383

Non-dipolar Wilson links for transverse-momentum-dependent wave functions  

E-print Network

We propose definitions of transverse-momentum-dependent wave functions with simpler soft subtractions for $k_T$ factorization of hard exclusive processes. The un-subtracted wave functions involve two pieces of non-light-like Wilson links, which are oriented in different directions, so that the rapidity singularity appearing in usual $k_T$ factorization is regularized, and the pinched singularity from Wilson-link self-energy corrections is alleviated to a logarithmic one. Then only a single soft function is required to remove the logarithmic soft divergence, and even no soft function is needed, when the two pieces of Wilson links are orthogonal to each other. We show at one-loop level that the simpler definitions with the non-dipolar Wilson links exhibit the same infrared behavior as the one proposed by Collins recently, and satisfy the similar evolution equation in Wilson-link rapidity.

Hsiang-nan Li; Yu-Ming Wang

2014-10-27

384

High-Speed Photographic Study of Wave Propagation and Impact Damage in Fused Silica and AlON Using the Edge-On Impact (EOI) Method  

NASA Astrophysics Data System (ADS)

An Edge-on Impact (EOI) technique, developed at the Ernst-Mach-Institute (EMI), coupled with a Cranz-Schardin high-speed camera, has been successfully utilized to visualize dynamic fracture in many brittle materials. In a typical test, the projectile strikes one edge of a specimen and damage formation and fracture propagation is recorded during the first 20 ?s after impact. In the present study, stress waves and damage propagation in fused silica and AlON were examined by means of two modified Edge-on Impact arrangements. In one arrangement, fracture propagation was observed simultaneously in side and top views of the specimens by means of two Cranz-Schardin cameras. In another arrangement, the photographic technique was modified by placing the specimen between crossed polarizers and using the photo-elastic effect to visualize the stress waves. Pairs of impact tests at approximately equivalent velocities were carried out in transmitted plane (shadowgraphs) and crossed polarized light.

Strassburger, E.; Patel, P.; McCauley, J. W.; Templeton, D. W.

2006-07-01

385

Cryptic impacts of temperature variability on amphibian immune function.  

PubMed

Ectothermic species living in temperate regions can experience rapid and potentially stressful changes in body temperature driven by abrupt weather changes. Yet, among amphibians, the physiological impacts of short-term temperature variation are largely unknown. Using an ex situ population of Cryptobranchus alleganiensis, an aquatic North American salamander, we tested the hypothesis that naturally occurring periods of temperature variation negatively impact amphibian health, either through direct effects on immune function or by increasing physiological stress. We exposed captive salamanders to repeated cycles of temperature fluctuations recorded in the population's natal stream and evaluated behavioral and physiological responses, including plasma complement activity (i.e. bacteria killing) against Pseudomonas aeruginosa, Escherichia coli and Aeromonas hydrophila. The best-fit model (?AICc=0, wi=0.9992) revealed 70% greater P. aeruginosa killing after exposure to variable temperatures and no evidence of thermal acclimation. The same model predicted 50% increased E. coli killing, but had weaker support (?AICc=1.8, wi=0.2882). In contrast, plasma defenses were ineffective against A. hydrophila, and other health indicators (leukocyte ratios, growth rates and behavioral patterns) were maintained at baseline values. Our data suggest that amphibians can tolerate, and even benefit from, natural patterns of rapid warming/cooling. Specifically, temperature variation can elicit increased activity of the innate immune system. This immune response may be adaptive in an unpredictable environment, and is undetectable by conventional health indicators (and hence considered cryptic). Our findings highlight the need to consider naturalistic patterns of temperature variation when predicting species' susceptibility to climate change. PMID:23948472

Terrell, Kimberly A; Quintero, Richard P; Murray, Suzan; Kleopfer, John D; Murphy, James B; Evans, Matthew J; Nissen, Bradley D; Gratwicke, Brian

2013-11-15

386

NO EFFECT OF HYDRODYNAMIC SHOCK WAVE ON PROTEIN FUNCTIONALITY OF BEEF MUSCLE  

Technology Transfer Automated Retrieval System (TEKTRAN)

The protein functionality of meat proteins after treatment with hydrodynamic shock wave was determined. Frankfurters (cooked to 71 deg C) were evaluated for cooking yield, CIE L*a*b*, nitrosylhemochrome, Texture Profile Analysis (hardness, cohesiveness), and stress and strain (torsion testing). Comp...

387

A Novel Conformal Field Theory Approach to Bulk Wave Functions in the  

E-print Network

A Novel Conformal Field Theory Approach to Bulk Wave Functions in the Fractional Quantum Hall of conformal field theory correlators. It starts from the LAUGHLIN states and their generalization following/c-spin conformal field theories. The enigmatic phe- nomenon of fractional statistics is described by twist fields

Flohr, Michael

388

Conformal field theory approach to bulk wave functions in the fractional quantum Hall effect  

E-print Network

Conformal field theory approach to bulk wave functions in the fractional quantum Hall effect field theory analogon of the composite fermion picture of Jain. Fractional statistics is described = -2 b/c-spin system as known from the Haldane-Rezayi state. In this way we derive conformal field

Flohr, Michael

389

Stress waves in functionally gradient materials and its use for material characterization  

Microsoft Academic Search

A method is presented to investigate elastic waves in functionally gradient material (FGM) plates excited by plane pressure wavelets. The FGM plate was first divided into linearly inhomogeneous elements (LIEs). A general solution for the equation of motion governing the LIE was derived. The general solution was then used together with the boundary and continuity conditions to obtain the displacement

G. R. Liu; X. Han; K. Y. Lam

1999-01-01

390

A wave-function Monte Carlo method for simulating conditional master equations  

E-print Network

Wave-function Monte Carlo methods are an important tool for simulating quantum systems, but the standard method cannot be used to simulate decoherence in continuously measured systems. Here we present a new Monte Carlo method for such systems. This was used to perform the simulations of a continuously measured nano-resonator in [Phys. Rev. Lett. 102, 057208 (2009)].

Kurt Jacobs

2010-01-21

391

Pseudospectral calculation of the wave function of helium and the negative hydrogen ion  

Microsoft Academic Search

We study the numerical solution of the nonrelativistic Schrödinger equation for two-electron atoms in ground and excited S states using pseudospectral (PS) methods of calculation. The calculation achieves convergence rates for the energy, Cauchy error in the wave function, and variance in local energy that are exponentially fast for all practical purposes. The method requires three separate subdomains to handle

Paul E. Grabowski; David F. Chernoff

2010-01-01

392

Pseudospectral calculation of the wave function of helium and the negative hydrogen ion  

Microsoft Academic Search

We study the numerical solution of the nonrelativistic Schroedinger equation for two-electron atoms in ground and excited S states using pseudospectral (PS) methods of calculation. The calculation achieves convergence rates for the energy, Cauchy error in the wave function, and variance in local energy that are exponentially fast for all practical purposes. The method requires three separate subdomains to handle

David F. Chernoff; Paul E. Grabowski

2010-01-01

393

Wave functions of a new kind of nonlinear single-mode squeezed state  

NASA Astrophysics Data System (ADS)

We explore the theoretical possibility of extending the usual squeezed state to those produced by nonlinear single-mode squeezing operators. We derive the wave functions of exp[?(ig/2)(P + P)|0rangle in the coordinate representation. A new operator's disentangling formula is derived as a by-product.

Fan, Hong-Yi; Da, Cheng; Chen, Jun-Hua

2014-12-01

394

Application of Exp-function method to Symmetric Regularized Long Wave (SRLW) equation  

Microsoft Academic Search

In this Letter, the Exp-function method with the aid of Maple is used to obtain generalized soliton solution and periodic solution with some free parameters for the Symmetric Regularized Long Wave (SRLW) equation. Suitable choice of parameters in the generalized solution leads to Darwish's solution [A.A. Darwish, A. Ramady, Chaos Solitons Fractals 33 (4) (2007) 1263]. The result shows that

Fei Xu

2008-01-01

395

MIMO Radar Space-Time Adaptive Processing Using Prolate Spheroidal Wave Functions  

E-print Network

1 MIMO Radar Space-Time Adaptive Processing Using Prolate Spheroidal Wave Functions Chun-Yang Chen and P. P. Vaidyanathan, Fellow, IEEE Abstract--In the traditional transmitting beamforming radar system- output (MIMO) radar system, the transmitter sends nonco- herent (possibly orthogonal) broad (possibly

Vaidyanathan, P. P.

396

Frequency-Domain Green's Functions for Radar Waves in Heterogeneous 2.5D Media  

EPA Science Inventory

Green?s functions for radar waves propagating in heterogeneous media may be calculated in the frequency domain using a hybrid of two numerical methods. The model is defined in the Cartesian coordinate system, and its electromagnetic properties may vary in the x and z directions, ...

397

Three-Dimensional Visualization of Wave Functions for Rotating Molecule: Plot of Spherical Harmonics  

ERIC Educational Resources Information Center

At an early stage of learning quantum chemistry, undergraduate students usually encounter the concepts of the particle in a box, the harmonic oscillator, and then the particle on a sphere. Rotational levels of a diatomic molecule can be well approximated by the energy levels of the particle on a sphere. Wave functions for the particle in a…

Nagaoka, Shin-ichi; Teramae, Hiroyuki; Nagashima, Umpei

2013-01-01

398

On the self-similar solution for the distribution function of particles accelerated by Alfven waves  

NASA Astrophysics Data System (ADS)

The equation representing the distribution function of relativistic particles accelerated by Alfven waves with bremsstrahlung radiation losses for the experimentally interesting case v = 2 is completely integrated and a general solution is found. The complete set of solutions for several boundary conditions has been obtained, including B = 2G.

Chanda, P. K.; Ray, D.

1983-05-01

399

ALYSSA NEY and DAVID Z ALBERT The Wave Function: Essays on the Metaphysics of Quantum  

E-print Network

REVIEW ALYSSA NEY and DAVID Z ALBERT The Wave Function: Essays on the Metaphysics of Quantum clearly how the fortunes of 3-space might be hostage to the metaphysics of quantum mechanics where Reichenbach didn't (in print, while alive), plunging into the metaphysics of the quantum state

Callender, Craig

400

Alternative Form of the Hydrogenic Wave Functions for an Extended, Uniformly Charged Nucleus.  

ERIC Educational Resources Information Center

Presented are forms of harmonic oscillator attraction and Coulomb wave functions which can be explicitly constructed and which lead to numerical results for the energy eigenvalues and eigenfunctions of the atomic system. The Schrodinger equation and its solution and specific cases of muonic atoms illustrating numerical calculations are included.…

Ley-Koo, E.; And Others

1980-01-01

401

Love waves propagation in functionally graded piezoelectric materials with quadratic variation  

Microsoft Academic Search

The propagation behavior of Love waves in a semi-infinite functionally graded piezoelectric material (FGPM) with a quadratic variation is addressed. The coupled electromechanical field equations are solved, and the dispersion relations, displacement, electric potential, and stress fields are obtained analytically for both electrically open and short conditions. The effects of gradient coefficient on phase velocity, group velocity, and electromechanical coupling

M. Eskandari; H. M. Shodja

2008-01-01

402

Orthogonal localized wave functions of an electron in a magnetic field E. I. Rashba  

E-print Network

Orthogonal localized wave functions of an electron in a magnetic field E. I. Rashba Department shape of exp( r2 /4l2 )/ 2 for r 2 l, where l is the magnetic length. This region makes a dominating for interacting electrons in a strong magnetic field have been developing rapidly in the past decade.1 They employ

Zhukov, Leonid

403

``Artificial Atoms'' in Magnetic Fields: Wave-Function Shaping and Phase-Sensitive Tunneling  

Microsoft Academic Search

We demonstrate the possibility to influence the shape of the wave functions in semiconductor quantum dots by the application of an external magnetic field Bz. The states of the so-called p shell, which show distinct orientations along the crystal axes for Bz=0, can be modified to become more and more circularly symmetric with an increasing field. Their changing probability density

Wen Lei; Christian Notthoff; Jie Peng; Dirk Reuter; Andreas Wieck; Gabriel Bester; Axel Lorke

2010-01-01

404

Determination of Non{Adiabatic Scattering Wave Functions in a Born{Oppenheimer Model  

E-print Network

Determination of Non{Adiabatic Scattering Wave Functions in a Born{Oppenheimer Model George A for the time dependent molecular Schrodinger equation in the Born{Oppenheimer limit. We assume the elec- tron. This component is shown to be exponentially small in the square of the Born{Oppenheimer parameter, due

Hagedorn, George A.

405

Determination of Non--Adiabatic Scattering Wave Functions in a Born--Oppenheimer Model  

E-print Network

Determination of Non--Adiabatic Scattering Wave Functions in a Born--Oppenheimer Model George A molecular SchrË?odinger equation in the Born--Oppenheimer limit. We assume the elec­ tron Hamiltonian has to be exponentially small in the square of the Born--Oppenheimer parameter, due to the Landau­Zener mechanism

406

Born-Oppenheimer wave function near level crossing J. E. Avron and A. Gordon  

E-print Network

Born-Oppenheimer wave function near level crossing J. E. Avron and A. Gordon Department of Physics, Technion, 32000 Haifa, Israel Received 18 June 2000; published 3 November 2000 The standard Born-Oppenheimer and Oppenheimer 1 paved the way toward applying quantum mechanics to mo- lecular spectra. In their paper

Avron, Joseph

407

Exact wave functions and geometric phases of a generalized driven oscillator  

E-print Network

The generalized invariant and its eigenstates of a general quadratic oscillator are found. The Schrödinger wave functions for the eigenstates are also found in analytically closed forms. The conditions for the existence of the cyclic initial state (CIS) are studied and the corresponding nonadiabatic Berry phase is calculated explicitly.

Lee, M H; Ji, J Y; Lee, Min-Ho; Kim, Hyeong-Chan; Ji, Jeong-Young

1997-01-01

408

Light hadron spectra and wave functions in quenched QCD with overlap quarks on a large lattice  

E-print Network

A simulation of quenched QCD with the overlap Dirac operator has been completed using 100 Wilson gauge configurations at beta=6 on an 18^3x64 lattice. We present results for meson and baryon masses, meson final state "wave functions'' and other observables.

Federico Berruto; Nicolas Garron; Christian Hoelbling; Joseph Howard; Laurent Lellouch; Silvia Necco; Claudio Rebbi; Noam Shoresh

2004-09-21

409

Standing wave vs Green's function approach to the Casimir force problem  

E-print Network

After a short recall of our previous standing wave approach to the Casimir force problem, we consider Lifshitz's temperature Green's function method and its virtues from a physical point of view. Using his formula, specialized for perfectly reflecting mirrors, we present a quantitative discussion of the temperature effect on the attractive force.

Frédéric Schuller; Renaud Savalle; Michael Neumann-Spallart

2012-05-29

410

Monte Carlo energy and variance-minimization techniques for optimizing many-body wave functions  

E-print Network

common type of trial wave function used in VMC and DMC calculations for at- oms, molecules and solids and Dn are Slater determinants of spin-up and spin-down single-particle orbit- als, the n in the single-particle orbitals forming the Slater determi- nants. The values of the parameters are obtained via

Kent, Paul

411

Electromagnetic wave emitting products and "Kikoh" potentiate human leukocyte functions.  

PubMed

Tourmaline (electric stone, a type of granite stone), common granite stone, ceramic disks, hot spring water and human palmar energy (called "Kikoh" in Japan and China), all which emit electromagnetic radiation in the far infrared region (wavelength 4-14 microns). These materials were thus examined for effects on human leukocyte activity and on lipid peroxidation of unsaturated fatty acids. It was revealed that these materials significantly increased intracellular calcium ion concentration, phagocytosis, and generation of reactive oxygen species in neutrophils, and the blastogenetic response of lymphocytes to mitogens. Chemotactic activity by neutrophils was also enhanced by exposure to tourmaline and the palm of "Kikohshi" i.e., a person who heals professionally by the laying on of hands. Despite the increase in reactive oxygen species generated by neutrophils, lipid peroxidation from unsaturated fatty acid was markedly inhibited by these four materials. The results suggest that materials emitting electromagnetic radiation in the far infrared range, which are widely used in Japan for cosmetic, therapeutic, and preservative purposes, appear capable of potentiating leukocyte functions without promoting oxidative injury. PMID:8406976

Niwa, Y; Iizawa, O; Ishimoto, K; Jiang, X; Kanoh, T

1993-09-01

412

Multi-functional Nanowire Evanescent Wave Optical Sensors  

SciTech Connect

Controlling the flow of photons through a fluidic media withsubwavelength optics is a major step towards the development of on-chipphotonic sensors. Central to this idea will be designing amulti-functional nanomaterial that can efficiently trap, route anddeliver light to various sensing channels, filters and detectors on aphotonic chip. Semiconductor nanowire waveguides offer an exceptionalsolution to the confinement of optical energy in solution and can bedirectly integrated into microfluidic devices. Here we demonstrate anovel optical sensing platform that utilizes the evanescent field of atin dioxide single crystalline waveguide to perform a wide array ofspectroscopic analyses including absorption, fluorescence and surfaceenhanced Raman on sub-picoliter probe volumes. Since the same waveguidecavity can transmit both broadband and monochromatic light it allowsmultiple modes of detection to be carried out on the same analyte. Tomove beyond less chemical specific optical techniques such as absorptionand fluorescence we exploit the amplified electric field around silvernanocubes to enhance the vibronic signatures of molecules present in theevanescent field. With excellent chemical resilience to strong acidicconditions, the waveguides can be completely cleaned from the attachedmetal nanoparticles making the devices fully reusable. These results openup the possibility of engineering self-contained, multiplexed photonicsensors that detect and identify chemical species in complex biologicaland environmental systems.

Sirbuly, Donald J.; Tao, Andrea; Law, Matt; Fan, Rong; Yang,Peidong

2006-10-18

413

Wave functions and half-off-shell t matrix of a two-particle system  

SciTech Connect

This paper obtains an integral representation that determines directly the partial wave functions and the half-off-shell t matrix of a two-particle system from scattering data. The representation has an explicitly controlled functional arbitrariness. If this is fixed in a manner equivalent to imposing the condition of locality on the interaction, the method developed is equivalent to the inverse scattering method. Other ways of fixing the arbitrariness correspond to different choices of nonlocal phase-equivalent potentials.

MuzaFarov, V.M.

1986-02-01

414

Optical mapping of amplitude and phase of excitonic wave functions in a quantum dot system  

Microsoft Academic Search

We propose a technique based on a near-field scanning optical microscope, able to measure the spatial variations of both amplitude and phase of the wave functions of the individual eigenstates of a quantum dot system. The proposed scheme is based on a near-field optical microscope working in collection mode combined with a Mach-Zehnder interferometer. We analyze the response function of

O. di Stefano; S. Savasta; G. Pistone; G. Martino; R. Girlanda

2003-01-01

415

The SCHRÖDINGER Propagator as a Wave Function of the Wheeler-De Witt Equation  

NASA Astrophysics Data System (ADS)

The eigenvalue equation of the dynamical Schrödinger operator in polar coordinates without potential is considered. An integral transformation in terms of the Bessel's functions is suggested as a solution. The eigenvalue equation is simplified to an ordinary equation in the time variable. The Schrödinger propagator is calculated with the solution of the eigenvalue equation, and used to find explicitly the wave function of the Wheeler-de Witt equation that describes gravity plus a perfect fluid.

Martinez-Morales, Jose L.

416

Configuration mixing of angular-momentum projected triaxial relativistic mean-field wave functions  

E-print Network

The framework of relativistic energy density functionals is extended to include correlations related to the restoration of broken symmetries and to fluctuations of collective variables. The generator coordinate method is used to perform configuration mixing of angular-momentum projected wave functions, generated by constrained self-consistent relativistic mean-field calculations for triaxial shapes. The effects of triaxial deformation and of $K$-mixing is illustrated in a study of spectroscopic properties of low-spin states in $^{24}$Mg.

J. M. Yao; J. Meng; P. Ring; D. Vretenar

2010-04-07

417

Configuration mixing of angular-momentum-projected triaxial relativistic mean-field wave functions  

SciTech Connect

The framework of relativistic energy-density functionals is extended to include correlations related to the restoration of broken symmetries and to fluctuations of collective variables. The generator coordinate method is used to perform configuration mixing of angular-momentum-projected wave functions, generated by constrained self-consistent relativistic mean-field calculations for triaxial shapes. The effects of triaxial deformation and of K mixing is illustrated in a study of spectroscopic properties of low-spin states in {sup 24}Mg.

Yao, J. M. [School of Physical Science and Technology, Southwest University, Chongqing 400715 (China); State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871 (China); Physik-Department der Technischen Universitaet Muenchen, D-85748 Garching (Germany); Meng, J. [State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871 (China); School of Physics and Nuclear Energy Engineering, Beihang University, Beijing 100191 (China); Ring, P. [Physik-Department der Technischen Universitaet Muenchen, D-85748 Garching (Germany); Vretenar, D. [Physics Department, Faculty of Science, University of Zagreb, 10000 Zagreb (Croatia)

2010-04-15

418

GPD and PDF modeling in terms of effective light-cone wave functions  

E-print Network

We employ models from effective two-body light-cone wave functions (LCWFs) to provide a link between generalized parton distributions (GPDs) and unintegrated parton distribution functions (uPDFs). Since we utilize the underlying Lorentz symmetry, GPDs can be entirely obtained from the parton number conserved LCWF overlaps. This also allows us to derive model constraints among GPDs. We illustrate that transversity distributions may be rather sizeable.

Dae Sung Hwang; Dieter Mueller

2011-08-18

419

Impact of mesostructure on functional properties of granular diamond composites  

NASA Astrophysics Data System (ADS)

Granular diamond composites are particulate reinforced composites, where the particulate phase is a grade of high-hardness polycrystalline diamond, embedded in a tougher, hard-material matrix. Granular diamond composites are hierarchically-structured materials. In addition to the macrostructure and microstructure, granular diamond composites have a mesostructure that encompasses the morphology of the matrix and granules and is characterized by parameters such as component volume fraction, granular sphericity, and matrix uniformity. The mesostructure is functionally designed to improve the performance of the composite in petroleum well-drilling applications by increasing the fracture resistance while maintaining the wear resistance. The impact of the mesostructure on the flexural strength, wear resistance, impact resistance, and in-field performance was measured. Physical testing showed that volume fraction of the tougher, matrix phase can be increased significantly before the wear resistance of the composite decreases appreciably. But the testing also showed that the method developed to produce the composites resulted in component materials with inferior properties. The flexural strength of a polycrystalline-diamond/tungsten-carbide material system was explored using several modeling techniques, including analytic, two-dimensional numeric, and three-dimensional numeric models. Residual stresses, arising from the change in conditions after the material is formed in a high-temperature, high-pressure sintering process, have a significant impact on the calculated strength of the composite. Dilatational residual stresses have never been treated in a rigorous manner in the literature and are often neglected completely. In this study, the thermal and dilatational residual stresses were modeled. Stresses from externally applied loads preferentially concentrate in the stiffer diamond phase. Thermal residual stresses strengthen the stiffer and weaker diamond phase through residual compression and weaken the carbide phase through residual tension. The dilatational residual stresses partially counteract the thermal residual stresses. Without thermal residual stresses the composite would have lower strength due to premature failure in the diamond phase. Without dilatational residual stresses the composite would have lower strength due to premature failure in the carbide phase. The strengths predicted by the enhanced models match the measured strengths quite well, despite significant uncertainty in the material properties and process parameters.

Harding, David Phillip

420

Waves generated by Asteroid impacts and their effects on US shorelines  

NASA Astrophysics Data System (ADS)

On February 15, 2013 an undetected ~17-20-m diameter asteroid entered earth's atmosphere and, due to its large entry speed of 18.6 km/s and its shallow entry angle, the asteroid exploded in an airburst over Chelyabinsk, Russia, generating a bright flash, producing many small fragment meteorites and causing a powerful shock wave which released the equivalent of ~440 kt TNT of energy. About 16 hours after the Chelyabinsk asteroid, the elongated ~20m by ~40m (~30 m diameter) NEA 2012 DA14 with an estimated mass of 40 kt neared the earth surface at ~28,100km, ~2.2 earth's diameter. These two consecutive events, which were unrelated and had drastically different orbits, generated considerable attention and awareness from the public, confusion among the local residents, and raised the issue of emergency response and preparedness of local, state and government agencies. LLNL and other government agencies have performed numerical simulations of a postulated asteroid impact onto the ocean and generated data to support an emergency preparedness exercise. We illustrate the exercise through the application of several codes from source (asteroid entry) to ocean impact (splash rim) to wave generation, propagation and interaction with the shoreline. Using state-of-the-art high performance computing codes we simulate three impact sites; one site is located off the eat coat by Maryland's shoreline and two other sites on the west coast: the San Francisco bay and the Los Angeles bay shorelines, respectively. Simulations were conducted not only under deterministic conditions but also under conditions of uncertainty. Uncertainty assessment of flood hazards zones and structural integrity of infrastructures will be presented. This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344, and partially funded by the Laboratory Directed Research and Development Program at LLNL under tracking code 12-ERD-005.

Ezzedine, S. M.; Miller, P. L.; Dearborn, D. S.; Dennison, D. S.; Glascoe, L. G.; Antoun, T.

2013-12-01

421

Ex vivo Characterization of Blast Wave Impact and Spinal Cord Tissue Deformation  

NASA Astrophysics Data System (ADS)

Primary blast injury on central nervous system is responsible for many of the war related casualties and mortalities. An ex vivo model system is developed to introduce a blast wave, generated from a shock tube, directly to spinal cord tissue sample. A high-speed shadowgraph system is utilized to visualize the development of the blast wave and its interaction with tissue sample. Surface deformation of the tissue sample is also measured for the analysis of internal stress and possible injury occurred within the tissue sample. Understanding the temporal development of the blast-tissue interaction provides valuable input for modeling blast-induced neurotrauma. Tracking the sample surface deformation as a function of time provides realistic boundary conditions for numerical simulation of injury process.

Chen, Jun; Gao, Jian; Connell, Sean; Shi, Riyi

2010-11-01

422

Explicit schemes for time propagating many-body wave functions  

NASA Astrophysics Data System (ADS)

Accurate theoretical data on many time-dependent processes in atomic and molecular physics and in chemistry require the direct numerical ab initio solution of the time-dependent Schrödinger equation, thereby motivating the development of very efficient time propagators. These usually involve the solution of very large systems of first-order differential equations that are characterized by a high degree of stiffness. In this contribution, we analyze and compare the performance of the explicit one-step algorithms of Fatunla and Arnoldi. Both algorithms have exactly the same stability function, therefore sharing the same stability properties that turn out to be optimum. Their respective accuracy, however, differs significantly and depends on the physical situation involved. In order to test this accuracy, we use a predictor-corrector scheme in which the predictor is either Fatunla's or Arnoldi's algorithm and the corrector, a fully implicit four-stage Radau IIA method of order 7. In this contribution, we consider two physical processes. The first one is the ionization of an atomic system by a short and intense electromagnetic pulse; the atomic systems include a one-dimensional Gaussian model potential as well as atomic hydrogen and helium, both in full dimensionality. The second process is the decoherence of two-electron quantum states when a time-independent perturbation is applied to a planar two-electron quantum dot where both electrons are confined in an anharmonic potential. Even though the Hamiltonian of this system is time independent the corresponding differential equation shows a striking stiffness which makes the time integration extremely difficult. In the case of the one-dimensional Gaussian potential we discuss in detail the possibility of monitoring the time step for both explicit algorithms. In the other physical situations that are much more demanding in term of computations, we show that the accuracy of both algorithms depends strongly on the degree of stiffness of the problem.

Frapiccini, Ana Laura; Hamido, Aliou; Schröter, Sebastian; Pyke, Dean; Mota-Furtado, Francisca; O'Mahony, Patrick F.; Madroñero, Javier; Eiglsperger, Johannes; Piraux, Bernard

2014-02-01

423

Impact of post-kidney transplant parathyroidectomy on allograft function  

PubMed Central

Background The impact of parathyroidectomy on allograft function in kidney transplant patients is unclear. Methods We conducted a retrospective, observational study of all kidney transplant recipients from 1988 to 2008 who underwent parathyroidectomy for uncontrolled hyperparathyroidism (n = 32). Post-parathyroidectomy, changes in estimated glomerular filtration rate (eGFR) and graft loss were recorded. Cross-sectional associations at baseline between eGFR and serum calcium, phosphate, and parathyroid hormone (PTH), and associations between their changes within subjects during the first two months post-parathyroidectomy were assessed. Results Post-parathyroidectomy, the mean eGFR declined from 51.19 mL/min/1.73 m2 at parathyroidectomy to 44.78 mL/min/1.73 m2 at two months (p < 0.0001). Subsequently, graft function improved, and by 12 months, mean eGFR recovered to 49.76 mL/min/1.73 m2 (p = 0.035). Decrease in serum PTH was accompanied by a decrease in eGFR (p = 0.0127) in the first two months post-parathyroidectomy. Patients whose eGFR declined by ? 20% (group 1) in the first two months post-parathyroidectomy were distinguished from the patients whose eGFR declined by <20% (group 2). The two groups were similar except that group 1 had a higher baseline mean serum PTH compared with group 2, although not significant (1046.7 ± 1034.2 vs. 476.6 ± 444.9, p = 0.14). In group 1, eGFR declined at an average rate of 32% (p < 0.0001) during the first month post-parathyroidectomy compared with 7% (p = 0.1399) in group 2, and the difference between these two groups was significant (p = 0.0003). The graft function recovered in both groups by one yr. During median follow-up of 66.00 ± 49.45 months, 6 (18%) patients lost their graft with a mean time to graft loss from parathyroidectomy of 37.2 ± 21.6 months. The causes of graft loss were rejection (n = 2), pyelonephritis (n = 1) and chronic allograft nephropathy (n = 3). No graft loss occurred during the first-year post-surgery. Conclusion Parathyroidectomy may lead to transient kidney allograft dysfunction with eventual recovery of graft function by 12 months post-parathyroidectomy. Higher level of serum PTH pre-parathyoidectomy is associated with a more profound decrease in eGFR post-parathyroidectomy. PMID:23448282

Parikh, Samir; Nagaraja, Haikady; Agarwal, Anil; Samavedi, Srinivas; Von Visger, Jon; Nori, Uday; Andreoni, Kenneth; Pesavento, Todd; Singh, Neeraj

2013-01-01

424

Accretion of Cometary Material as a Function of Impact Angle  

Microsoft Academic Search

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

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

2003-01-01

425

Universal Probability Distribution for the Wave Function of a Quantum System Entangled with Its Environment  

E-print Network

A quantum system (with Hilbert space $\\mathscr{H}_1$) entangled with its environment (with Hilbert space $\\mathscr{H}_2$) is usually not attributed a wave function but only a reduced density matrix $\\rho_1$. Nevertheless, there is a precise way of attributing to it a random wave function $\\psi_1$, called its conditional wave function, whose probability distribution $\\mu_1$ depends on the entangled wave function $\\psi\\in\\mathscr{H}_1\\otimes\\mathscr{H}_2$ in the Hilbert space of system and environment together. It also depends on a choice of orthonormal basis of $\\mathscr{H}_2$ but in relevant cases, as we show, not very much. We prove several universality (or typicality) results about $\\mu_1$, e.g., that if the environment is sufficiently large then for every orthonormal basis of $\\mathscr{H}_2$, most entangled states $\\psi$ with given reduced density matrix $\\rho_1$ are such that $\\mu_1$ is close to one of the so-called GAP (Gaussian adjusted projected) measures, $GAP(\\rho_1)$. We also show that, for most entangled states $\\psi$ from a microcanonical subspace (spanned by the eigenvectors of the Hamiltonian with energies in a narrow interval $[E,E+\\delta E]$) and most orthonormal bases of $\\mathscr{H}_2$, $\\mu_1$ is close to $GAP(\\mathrm{tr}_2 \\rho_{mc})$ with $\\rho_{mc}$ the normalized projection to the microcanonical subspace. In particular, if the coupling between the system and the environment is weak, then $\\mu_1$ is close to $GAP(\\rho_\\beta)$ with $\\rho_\\beta$ the canonical density matrix on $\\mathscr{H}_1$ at inverse temperature $\\beta=\\beta(E)$. This provides the mathematical justification of our claim in [J. Statist. Phys. 125:1193 (2006), http://arxiv.org/abs/quant-ph/0309021] that $GAP$ measures describe the thermal equilibrium distribution of the wave function.

Sheldon Goldstein; Joel L. Lebowitz; Christian Mastrodonato; Roderich Tumulka; Nino Zanghi

2015-02-10

426

Generalized minimum-phase relations for memory functions associated with wave phenomena  

NASA Astrophysics Data System (ADS)

Memory functions occur as temporal convolution operators in governing equations of wave propagation and generally account for the instantaneous and non-instantaneous responses of a medium. The specific memory function that is causal and stable, and the inverse of which is causal and stable as well, is conventionally referred to as a minimum-phase (MP) function. Its amplitude and phase spectra are not independent, but related through MP-relations; that is, Kramers-Kronig relations between the amplitude and phase spectra. In this paper, we derive generalized MP-relations for a memory function that does not necessarily meet the stability requirements; such functions are often encountered in the geophysical context. We still address the function as MP because its phase spectrum exhibits minimum group delay, like that of a conventional MP function. We successfully tested the derived relations for the well-known Maxwell, Kelvin-Voigt and Zener compressibility models used in acoustics/elastodynamics, the dynamic permeability used in poroelasticity and the electrokinetic coefficient used in coupled acoustics and electromagnetics. In these fields, the derived relations can be applied for the determining the involved memory function using numerical or laboratory experiments; only the amplitude or the phase spectrum needs to be measured and the other can be calculated. The relations also have applications in effective-medium theory and for any other wave phenomenon that employs memory functions.

N. van Dalen, Karel; Slob, Evert; Schoemaker, Christiaan

2013-12-01

427

Selection on soil microbiomes reveals reproducible impacts on plant function.  

PubMed

Soil microorganisms found in the root zone impact plant growth and development, but the potential to harness these benefits is hampered by the sheer abundance and diversity of the players influencing desirable plant traits. Here, we report a high level of reproducibility of soil microbiomes in altering plant flowering time and soil functions when partnered within and between plant hosts. We used a multi-generation experimental system using Arabidopsis thaliana Col to select for soil microbiomes inducing earlier or later flowering times of their hosts. We then inoculated the selected microbiomes from the tenth generation of plantings into the soils of three additional A. thaliana genotypes (Ler, Be, RLD) and a related crucifer (Brassica rapa). With the exception of Ler, all other plant hosts showed a shift in flowering time corresponding with the inoculation of early- or late-flowering microbiomes. Analysis of the soil microbial community using 16?S rRNA gene sequencing showed distinct microbiota profiles assembling by flowering time treatment. Plant hosts grown with the late-flowering-associated microbiomes showed consequent increases in inflorescence biomass for three A. thaliana genotypes and an increase in total biomass for B. rapa. The increase in biomass was correlated with two- to five-fold enhancement of microbial extracellular enzyme activities associated with nitrogen mineralization in soils. The reproducibility of the flowering phenotype across plant hosts suggests that microbiomes can be selected to modify plant traits and coordinate changes in soil resource pools. PMID:25350154

Panke-Buisse, Kevin; Poole, Angela C; Goodrich, Julia K; Ley, Ruth E; Kao-Kniffin, Jenny

2015-01-01

428

The Impact of Chromospheric Activity on Observed Initial Mass Functions  

E-print Network

Using recently established empirical calibrations for the impact of chromospheric activity on the radii, effective temperatures, and estimated masses of active low-mass stars and brown dwarfs, we reassess the shape of the initial mass function (IMF) across the stellar/substellar boundary in the Upper Sco star-forming region (age 5-10 Myr). We adjust the observed effective temperatures to warmer values using the observed strength of the chromospheric H$\\alpha$ emission, and redetermine the estimated masses of objects using pre--main-sequence evolutionary tracks in the H-R diagram. The effect of the activity-adjusted temperatures is to shift the objects to higher masses by 3-100%. While the slope of the resulting IMF at substellar masses is not strongly changed, the peak of the IMF does shift from ~0.06 to ~0.11 Msun. Moreover, for objects with masses ~0.2 Msun, the ratio of brown dwarfs to stars changes from ~80% to ~33%. These results suggest that activity corrections are essential for studies of the substell...

Stassun, Keivan G; Dupuy, Trent; Kratter, Kaitlin

2014-01-01

429

Impact of metal nanoparticles on germ cell viability and functionality.  

PubMed

Metal nanoparticles play an increasing role in consumer products, biomedical applications and in the work environment. Therefore, the effects of nanomaterials need to be properly understood. This applies especially to their potential reproductive toxicology (nanoreprotoxicity), because any shortcomings in this regard would be reflected into the next generation. This review is an attempt to summarize the current knowledge regarding the effects of nanoparticles on reproductive outcomes. A comprehensive collection of significant experimental nanoreprotoxicity data is presented, which highlight how the toxic effect of nanoparticles can be influenced, not only by the particles' chemical composition, but also by particle size, surface modification, charge and to a considerable extent on the experimental set-up. The period around conception is characterized by considerable cytological and molecular restructuring and is therefore particularly sensitive to disturbances. Nanoparticles are able to penetrate through biological barriers into reproductive tissue and at least can have an impact on sperm vitality and function as well as embryo development. Particularly, further investigations are urgently needed on the repetitively shown effect of the ubiquitously used titanium dioxide nanoparticles on the development of the nervous system. It is recommended that future research focuses more on the exact mechanism behind the observed effects, because such information would facilitate the production of nanoparticles with increased biocompatibility. PMID:22827393

Taylor, U; Barchanski, A; Kues, W; Barcikowski, S; Rath, D

2012-08-01

430

A numerically stable formulation of the Green's function parabolic equation: Subtracting the surface-wave pole.  

PubMed

The original formulation of the Green's function parabolic equation (GFPE) can have numerical accuracy problems for large normalized surface impedances. To solve the accuracy problem, an improved form of the GFPE has been developed. The improved GFPE formulation is similar to the original formulation, but it has the surface-wave pole "subtracted." The improved GFPE is shown to be accurate for surface impedances varying over 2 orders of magnitude, with the largest having a magnitude exceeding 1000. Also, the improved formulation is slightly faster than the original formulation because the surface-wave component does not have to be computed separately. PMID:25618104

Gilbert, Kenneth E

2015-01-01

431

Quantum diffusion wave-function approach to two-dimensional vibronic spectroscopy  

NASA Astrophysics Data System (ADS)

We apply the quantum diffusion wavefunction approach to calculate vibronic two-dimensional (2D) spectra. As an example, we use a system consisting of two electronic states with harmonic oscillator potentials which are coupled to a bath and interact with three time-delayed laser pulses. The first- and second-order perturbative wave functions which enter into the expression for the third-order polarization are determined for a sufficient number of stochastic runs. The wave-packet approach, besides being an alternative technique to calculate the spectra, offers an intuitive insight into the dissipation dynamics and its relation to the 2D vibronic spectra.

Wehner, Johannes; Falge, Mirjam; Strunz, Walter T.; Engel, Volker

2014-10-01

432

Frequency-domain Green's functions for radar waves in heterogeneous 2.5D media  

USGS Publications Warehouse

Green's functions for radar waves propagating in heterogeneous 2.5D media might be calculated in the frequency domain using a hybrid method. The model is defined in the Cartesian coordinate system, and its electromagnetic properties might vary in the x- and z-directions, but not in the y-direction. Wave propagation in the x- and z-directions is simulated with the finite-difference method, and wave propagation in the y-direction is simulated with an analytic function. The absorbing boundaries on the finite-difference grid are perfectly matched layers that have been modified to make them compatible with the hybrid method. The accuracy of these numerical Greens functions is assessed by comparing them with independently calculated Green's functions. For a homogeneous model, the magnitude errors range from -4.16% through 0.44%, and the phase errors range from -0.06% through 4.86%. For a layered model, the magnitude errors range from -2.60% through 2.06%, and the phase errors range from -0.49% through 2.73%. These numerical Green's functions might be used for forward modeling and full waveform inversion. ?? 2009 Society of Exploration Geophysicists. All rights reserved.

Ellefsen, K.J.; Croize, D.; Mazzella, A.T.; McKenna, J.R.

2009-01-01

433

Relations Between Low-lying Quantum Wave Functions and Solutions of the Hamilton-Jacobi Equation  

E-print Network

We discuss a new relation between the low lying Schroedinger wave function of a particle in a one-dimentional potential V and the solution of the corresponding Hamilton-Jacobi equation with -V as its potential. The function V is $\\geq 0$, and can have several minina (V=0). We assume the problem to be characterized by a small anhamornicity parameter $g^{-1}$ and a much smaller quantum tunneling parameter $\\epsilon$ between these different minima. Expanding either the wave function or its energy as a formal double power series in $g^{-1}$ and $\\epsilon$, we show how the coefficients of $g^{-m}\\epsilon^n$ in such an expansion can be expressed in terms of definite integrals, with leading order term determined by the classical solution of the Hamilton-Jacobi equation. A detailed analysis is given for the particular example of quartic potential $V={1/2}g^2(x^2-a^2)^2$.

R. Friedberg; T. D. Lee; W. Q. Zhao

1999-10-12

434

Harmonic-oscillator excitations of precise few-body wave functions  

E-print Network

A method for calculating the occupation probability of the number of harmonic oscillator (HO) quanta is developed for a precise few-body wave function obtained in a correlated Gaussian basis. The probability distributions of two- to four-nucleon wave functions obtained using different nucleon- nucleon (NN) interactions are analyzed to gain insight into the characteristic behavior of the various interactions. Tensor correlations as well as short-range correlations play a crucial role in enhancing the probability of high HO excitations. For the excited states of 4He, the interaction dependence is much less because high HO quanta are mainly responsible for describing the relative motion function between the 3N+N (3H+p and 3He+n) clusters.

W. Horiuchi; Y. Suzuki

2014-08-21

435

Time asymptotics of the Schroedinger wave function in time-periodic potentials  

E-print Network

We study the transition to the continuum of an initially bound quantum particle in $\\RR^d$, $d=1,2,3$, subjected, for $t\\ge 0$, to a time periodic forcing of arbitrary magnitude. The analysis is carried out for compactly supported potentials, satisfying certain auxiliary conditions. It provides complete analytic information on the time Laplace transform of the wave function. From this, comprehensive time asymptotic properties (Borel summable transseries) follow. We obtain in particular a criterion for whether the wave function gets fully delocalized (complete ionization). This criterion shows that complete ionization is generic and provides a convenient test for particular cases. When satisfied it implies absence of discrete spectrum and resonances of the associated Floquet operator. As an illustration we show that the parametric harmonic perturbation of a potential chosen to be any nonzero multiple of the characteristic function of a measurable compact set has this property.

O. Costin; R. D. Costin; J. L. Lebowitz

2006-08-13

436

The concept of phenomenological light-front wave functions -- Regge improved diquark model predictions  

E-print Network

We introduce a classification scheme for parton distribution models and we model generalized parton distributions (GPDs), their form factors, and parton distribution functions (PDFs), integrated and unintegrated ones, in terms of unintegrated double distributions that are obtained from the parton number conserved overlap of effective light-front wave functions. For a so-called "spherical" model we present general expressions for all twist-two related non-perturbative quantities in terms of one effective light-front wave function, including chiral-odd GPDs. We also discuss the Regge improvement of such quark models from the $s$-channel point of view and study the relations between zero-skewness GPDs and unintegrated PDFs on a more general ground. Finally, we provide a few phenomenological applications that emphasize the role of orbital angular momenta.

Dieter Müller; Dae Sung Hwang

2014-07-07

437

Expansion of X-ray form factor for close shell using uncorrelated wave function  

SciTech Connect

The atomic scattering factor has been studied for Be+ve, and B+2ve ions using the uncorrelated wave function (Hartree-Fock (HF)) for inter particle electronic shells. The physical importance of this factor appears in its relation to several important atomic properties as, the coherent scattering intensity, the total scattering intensity, the incoherent scattering function, the coherent scattering cross section, the total incoherent cross section, the nuclear magnetic shielding constant, the geometrical structure factor. Also there is one atomic properties the one particle radial density distribution function D(r)has been studied using the partitioning technique.

AL-Robayi, Enas M. [Babylon University , College of Science for Women, laser Physics Department, Hilla (Iraq)

2013-12-16

438

Assessments of Arterial Stiffness and Endothelial Function Using Pulse Wave Analysis  

PubMed Central

Conventionally, the assessments of endothelial function and arterial stiffness require different sets of equipment, making the inclusion of both tests impractical for clinical and epidemiological studies. Pulse wave analysis (PWA) provides useful information regarding the mechanical properties of the arterial tree and can also be used to assess endothelial function. PWA is a simple, valid, reliable, and inexpensive technique, offering great clinical and epidemiological potential. The current paper will outline how to measure arterial stiffness and endothelial function using this technique and include discussion of validity and reliability. PMID:22666595

Stoner, Lee; Young, Joanna M.; Fryer, Simon

2012-01-01

439

Expansion of X-ray form factor for close shell using uncorrelated wave function  

NASA Astrophysics Data System (ADS)

The atomic scattering factor has been studied for Be+ve, and B+2ve ions using the uncorrelated wave function (Hartree-Fock (HF)) for inter particle electronic shells. The physical importance of this factor appears in its relation to several important atomic properties as, the coherent scattering intensity, the total scattering intensity, the incoherent scattering function, the coherent scattering cross section, the total incoherent cross section, the nuclear magnetic shielding constant, the geometrical structure factor. Also there is one atomic properties the one particle radial density distribution function D(r)has been studied using the partitioning technique.

AL-Robayi, Enas M.

2013-12-01

440

Modeling the functional network of primary intercellular Ca$^{2+}$ wave propagation in astrocytes and its application to study drug effects  

E-print Network

We introduce a simple procedure of multivariate signal analysis to uncover the functional connectivity among cells composing a living tissue and describe how to apply it for extracting insight on the effect of drugs in the tissue. The procedure is based on the covariance matrix of time resolved activity signals. By determining the time-lag that maximizes covariance, one derives the weight of the corresponding connection between cells. Introducing simple constraints, it is possible to conclude whether pairs of cells are functionally connected and in which direction. After testing the method against synthetic data we apply it to study intercellular propagation of Ca$^{2+}$ waves in astrocytes following an external stimulus, with the aim of uncovering the functional cellular connectivity network. Our method proves to be particularly suited for this type of networking signal propagation where signals are pulse-like and have short time-delays, and is shown to be superior to standard methods, namely a multivariate Granger algorithm. Finally, based the statistical analysis of the connection weight distribution, we propose simple measures for assessing the impact of drugs on the functional connectivity between cells.

Marcelo Pires; Frank Raischel; Sandra Vaz; Andreia Cruz-Silva; Ana Sebastião; Pedro G. Lind

2014-06-10