Discrete Bose-Einstein spectra

International Nuclear Information System (INIS)

Vlad, Valentin I.; Ionescu-Pallas, Nicholas

2001-03-01

The Bose-Einstein energy spectrum of a quantum gas, confined in a rigid cubic box, is shown to become discrete and strongly dependent on the box geometry (size L), temperature, T and atomic mass number, A at , in the region of small γ=A at TV 1/3 . This behavior is the consequence of the random state degeneracy in the box. Furthermore, we demonstrate that the total energy does not obey the conventional law any longer, but a new law, which depends on γ and on the quantum gas fugacity. This energy law imposes a faster decrease to zero than it is classically expected, for γ→0. The lighter the gas atoms, the higher the temperatures or the box size, for the same effects in the discrete Bose-Einstein regime. (author)

Modelling of discrete TDS-spectrum of hydrogen desorption

Science.gov (United States)

Rodchenkova, Natalia I.; Zaika, Yury V.

2015-12-01

High concentration of hydrogen in metal leads to hydrogen embrittlement. One of the methods to evaluate the hydrogen content is the method of thermal desorption spectroscopy (TDS). As the sample is heated under vacuumization, atomic hydrogen diffuses inside the bulk and is desorbed from the surface in the molecular form. The extraction curve (measured by a mass-spectrometric analyzer) is recorded. In experiments with monotonous external heating it is observed that background hydrogen fluxes from the extractor walls and fluxes from the sample cannot be reliably distinguished. Thus, the extraction curve is doubtful. Therefore, in this case experimenters use discrete TDS-spectrum: the sample is removed from the analytical part of the device for the specified time interval, and external temperature is then increased stepwise. The paper is devoted to the mathematical modelling and simulation of experimental studies. In the corresponding boundary-value problem with nonlinear dynamic boundary conditions physical- chemical processes in the bulk and on the surface are taken into account: heating of the sample, diffusion in the bulk, hydrogen capture by defects, penetration from the bulk to the surface and desorption. The model aimed to analyze the dynamics of hydrogen concentrations without preliminary artificial sample saturation. Numerical modelling allows to choose the point on the extraction curve that corresponds to the initial quantity of the surface hydrogen, to estimate the values of the activation energies of diffusion, desorption, parameters of reversible capture and hydride phase decomposition.

Modelling of discrete TDS-spectrum of hydrogen desorption

International Nuclear Information System (INIS)

Rodchenkova, Natalia I; Zaika, Yury V

2015-01-01

High concentration of hydrogen in metal leads to hydrogen embrittlement. One of the methods to evaluate the hydrogen content is the method of thermal desorption spectroscopy (TDS). As the sample is heated under vacuumization, atomic hydrogen diffuses inside the bulk and is desorbed from the surface in the molecular form. The extraction curve (measured by a mass-spectrometric analyzer) is recorded. In experiments with monotonous external heating it is observed that background hydrogen fluxes from the extractor walls and fluxes from the sample cannot be reliably distinguished. Thus, the extraction curve is doubtful. Therefore, in this case experimenters use discrete TDS-spectrum: the sample is removed from the analytical part of the device for the specified time interval, and external temperature is then increased stepwise. The paper is devoted to the mathematical modelling and simulation of experimental studies. In the corresponding boundary-value problem with nonlinear dynamic boundary conditions physical- chemical processes in the bulk and on the surface are taken into account: heating of the sample, diffusion in the bulk, hydrogen capture by defects, penetration from the bulk to the surface and desorption. The model aimed to analyze the dynamics of hydrogen concentrations without preliminary artificial sample saturation. Numerical modelling allows to choose the point on the extraction curve that corresponds to the initial quantity of the surface hydrogen, to estimate the values of the activation energies of diffusion, desorption, parameters of reversible capture and hydride phase decomposition. (paper)

Ultrahigh-energy cosmic-ray spectrum

International Nuclear Information System (INIS)

Hill, C.T.; Schramm, D.N.

1985-01-01

We analyze the evolution of the ultrahigh-energy cosmic-ray spectrum upon traversing the 2.7 0 K microwave background with respect to pion photoproduction, pair-production reactions, and cosmological effects. Our approach employs exact transport equations which manifestly conserve nucleon number and embody the laboratory details of these reactions. A spectrum enhancement appears around 6 x 10 19 eV due to the ''pile-up'' of energy-degraded nucleons, and a ''dip'' occurs around 10 19 eV due to combined effects. Both of these features appear in the observational spectrum. We analyze the resulting neutrino spectrum and the effects of cosmological source distributions. We present a complete model of the ultrahigh-energy spectrum and anisotropy in reasonable agreement with observation and which predicts an observable electron-neutrino spectrum

On the Discrete Spectrum of the Nonstationary Schrödinger Equation and Multipole Lumps of the Kadomtsev-Petviashvili I Equation

Science.gov (United States)

Villarroel, Javier; Ablowitz, Mark J.

The discrete spectrum of the nonstationary Schrödinger equation and localized solutions of the Kadomtsev-Petviashvili-I (KPI) equation are studied via the inverse scattering transform. It is shown that there exist infinitely many real and rationally decaying potentials which correspond to a discrete spectrum whose related eigenfunctions have multiple poles in the spectral parameter. An index or winding number is asssociated with each of these solutions. The resulting localized solutions of KPI behave as collection of individual humps with nonuniform dynamics.

On the discrete spectrum of the Dirac operator on bent chain quantum graph

Directory of Open Access Journals (Sweden)

Belov Michail

2017-01-01

Full Text Available We study Dirac operators on an infinite quantum graph of a bent chain form which consists of identical rings connected at the touching points by δ-couplings with a parameter α ∈ ℝ. We are interested in the discrete spectrum of the corresponding Hamiltonian. It can be non-empty due to a local (geometrical perturbation of the corresponding infinite chain of rings. The quantum graph of analogous geometry with the Schrodinger operator on the edges was considered by Duclos, Exner and Turek in 2008. They showed that the absence of δ-couplings at vertices (i.e. the Kirchhoff condition at the vertices lead to the absence of eigenvalues. We consider the relativistic particle (the Dirac operator instead of the Schrodinger one but the result is analogous. Quantum graphs of such type are suitable for description of grapheme-based nanostructures. It is established that the negativity of α is the necessary and sufficient condition for the existence of eigenvalues of the Dirac operator (i.e. the discrete spectrum of the Hamiltonian in this case is not empty. The continuous spectrum of the Hamiltonian for bent chain graph coincides with that for the corresponding straight infinite chain. Conditions for appearance of more than one eigenvalue are obtained. It is related to the bending angle. The investigation is based on the transfer-matrix approach. It allows one to reduce the problem to an algebraic task. δ-couplings was introduced by the operator extensions theory method.

Three-dimensional poor man's Navier-Stokes equation: a discrete dynamical system exhibiting k(-5/3) inertial subrange energy scaling.

Science.gov (United States)

McDonough, J M

2009-06-01

Outline of the derivation and mathematical and physical interpretations are presented for a discrete dynamical system known as the "poor man's Navier-Stokes equation." Numerical studies demonstrate that velocity fields produced by this dynamical system are similar to those seen in laboratory experiments and in detailed simulations, and they lead to scaling for the turbulence kinetic energy spectrum in accord with Kolmogorov K41 theory.

Digital Watermarks Using Discrete Wavelet Transformation and Spectrum Spreading

Directory of Open Access Journals (Sweden)

Ryousuke Takai

2003-12-01

Full Text Available In recent tears, digital media makes rapid progress through the development of digital technology. Digital media normally assures fairly high quality, nevertheless can be easily reproduced in a perfect form. This perfect reproducibility takes and advantage from a certain point of view, while it produces an essential disadvantage, since digital media is frequently copied illegally. Thus the problem of the copyright protection becomes a very important issue. A solution of this problem is to embed digital watermarks that is not perceived clearly by usual people, but represents the proper right of original product. In our method, the images data in the frequency domain are transformed by the Discrete Wavelet Transform and analyzed by the multi resolution approximation, [1]. Further, the spectrum spreading is executed by using PN-sequences. Choi and Aizawa [7] embed watermarks by using block correlation of DCT coefficients. Thus, we apply Discrete Cosine Transformation, abbreviated to DCT, instead of the Fourier transformation in order to embed watermarks.If the value of this variance is high then we decide that the block has bigger magnitude for visual fluctuations. Henceforth, we may embed stronger watermarks, which gives resistance for images processing, such as attacks and/or compressions.

Spectrum Control through Discrete Frequency Diffraction in the Presence of Photonic Gauge Potentials

Science.gov (United States)

Qin, Chengzhi; Zhou, Feng; Peng, Yugui; Sounas, Dimitrios; Zhu, Xuefeng; Wang, Bing; Dong, Jianji; Zhang, Xinliang; Alù; , Andrea; Lu, Peixiang

2018-03-01

By using optical phase modulators in a fiber-optical circuit, we theoretically and experimentally demonstrate large control over the spectrum of an impinging signal, which may evolve analogously to discrete diffraction in spatial waveguide arrays. The modulation phase acts as a photonic gauge potential in the frequency dimension, realizing efficient control of the central frequency and bandwidth of frequency combs. We experimentally achieve a 50 GHz frequency shift and threefold bandwidth expansion of an impinging comb, as well as the frequency analogue of various refraction phenomena, including negative refraction and perfect focusing in the frequency domain, both for discrete and continuous incident spectra. Our study paves a promising way towards versatile frequency management for optical communications and signal processing using time modulation schemes.

Discrete spectrum of the two-center problem of p bar He+ atomcule

International Nuclear Information System (INIS)

Pavlov, D.V.; Puzynin, I.V.; Vinitskij, S.I.

1999-01-01

A discrete spectrum of the two-center Coulomb problem of p bar He + system is studied. For solving this problem the finite-difference scheme of the 4th-order and the continuous analog of Newton's method are applied. The algorithm for calculation of eigenvalues and eigenfunctions with optimization of the parameter of the fractional-rational transformation of the quasiradial variable to a finite interval is developed. The specific behaviour of the solutions in a vicinity of the united and separated atoms is discussed

Instructing Individuals to Deliver Discrete-Trials Teaching to Children with Autism Spectrum Disorders: A Review

Science.gov (United States)

Thomson, Kendra; Martin, Garry L.; Arnal, Lindsay; Fazzio, Daniela; Yu, C. T.

2009-01-01

Early intensive behavioral intervention (EIBI) has been identified as the treatment of choice for children with autism spectrum disorders. A common strategy for conducting EIBI is discrete-trials teaching (DTT). There is a demand for research-based, economical, rapid training techniques to teach tutors and parents of children with autism to…

Energy spectrum of buoyancy-driven turbulence

KAUST Repository

Kumar, Abhishek; Chatterjee, Anando G.; Verma, Mahendra K.

2014-01-01

Using high-resolution direct numerical simulation and arguments based on the kinetic energy flux Πu, we demonstrate that, for stably stratified flows, the kinetic energy spectrum Eu(k)∼k-11/5, the potential energy spectrum Eθ(k)∼k-7/5, and Πu(k)∼k-4

Sparse signal reconstruction from polychromatic X-ray CT measurements via mass attenuation discretization

International Nuclear Information System (INIS)

Gu, Renliang; Dogandžić, Aleksandar

2014-01-01

We propose a method for reconstructing sparse images from polychromatic x-ray computed tomography (ct) measurements via mass attenuation coefficient discretization. The material of the inspected object and the incident spectrum are assumed to be unknown. We rewrite the Lambert-Beer’s law in terms of integral expressions of mass attenuation and discretize the resulting integrals. We then present a penalized constrained least-squares optimization approach for reconstructing the underlying object from log-domain measurements, where an active set approach is employed to estimate incident energy density parameters and the nonnegativity and sparsity of the image density map are imposed using negative-energy and smooth ℓ 1 -norm penalty terms. We propose a two-step scheme for refining the mass attenuation discretization grid by using higher sampling rate over the range with higher photon energy, and eliminating the discretization points that have little effect on accuracy of the forward projection model. This refinement allows us to successfully handle the characteristic lines (Dirac impulses) in the incident energy density spectrum. We compare the proposed method with the standard filtered backprojection, which ignores the polychromatic nature of the measurements and sparsity of the image density map. Numerical simulations using both realistic simulated and real x-ray ct data are presented

Energy Minimization of Discrete Protein Titration State Models Using Graph Theory

Science.gov (United States)

Purvine, Emilie; Monson, Kyle; Jurrus, Elizabeth; Star, Keith; Baker, Nathan A.

2016-01-01

There are several applications in computational biophysics which require the optimization of discrete interacting states; e.g., amino acid titration states, ligand oxidation states, or discrete rotamer angles. Such optimization can be very time-consuming as it scales exponentially in the number of sites to be optimized. In this paper, we describe a new polynomial-time algorithm for optimization of discrete states in macromolecular systems. This algorithm was adapted from image processing and uses techniques from discrete mathematics and graph theory to restate the optimization problem in terms of “maximum flow-minimum cut” graph analysis. The interaction energy graph, a graph in which vertices (amino acids) and edges (interactions) are weighted with their respective energies, is transformed into a flow network in which the value of the minimum cut in the network equals the minimum free energy of the protein, and the cut itself encodes the state that achieves the minimum free energy. Because of its deterministic nature and polynomial-time performance, this algorithm has the potential to allow for the ionization state of larger proteins to be discovered. PMID:27089174

Energy Minimization of Discrete Protein Titration State Models Using Graph Theory.

Science.gov (United States)

Purvine, Emilie; Monson, Kyle; Jurrus, Elizabeth; Star, Keith; Baker, Nathan A

2016-08-25

There are several applications in computational biophysics that require the optimization of discrete interacting states, for example, amino acid titration states, ligand oxidation states, or discrete rotamer angles. Such optimization can be very time-consuming as it scales exponentially in the number of sites to be optimized. In this paper, we describe a new polynomial time algorithm for optimization of discrete states in macromolecular systems. This algorithm was adapted from image processing and uses techniques from discrete mathematics and graph theory to restate the optimization problem in terms of "maximum flow-minimum cut" graph analysis. The interaction energy graph, a graph in which vertices (amino acids) and edges (interactions) are weighted with their respective energies, is transformed into a flow network in which the value of the minimum cut in the network equals the minimum free energy of the protein and the cut itself encodes the state that achieves the minimum free energy. Because of its deterministic nature and polynomial time performance, this algorithm has the potential to allow for the ionization state of larger proteins to be discovered.

Josephson junction in the quantum mesoscopic electric circuits with charge discreteness

Science.gov (United States)

Pahlavani, H.

2018-04-01

A quantum mesoscopic electrical LC-circuit with charge discreteness including a Josephson junction is considered and a nonlinear Hamiltonian that describing the dynamic of such circuit is introduced. The quantum dynamical behavior (persistent current probability) is studied in the charge and phase regimes by numerical solution approaches. The time evolution of charge and current, number-difference and the bosonic phase and also the energy spectrum of a quantum mesoscopic electric LC-circuit with charge discreteness that coupled with a Josephson junction device are investigated. We show the role of the coupling energy and the electrostatic Coulomb energy of the Josephson junction in description of the quantum behavior and the spectral properties of a quantum mesoscopic electrical LC-circuits with charge discreteness.

Testing the discreteness of spacetime at low energies

International Nuclear Information System (INIS)

Chardin, G.

1994-01-01

Expected at the Planck scale, the discreteness of spacetime can hardly be tested at such high energies in a foreseable future. However, the Bekenstein relation suggests another approach, based on the study of time-asymmetry. After a brief introduction to discrete physics, the relation between gravitation and discreteness on the one hand, and between gravitation and time-asymmetry on the other was investigated. These relations have led to reconsider the possibility that CP violation in the neutral kaon system, the only known microscopic 'arrow of time', could be attributed to gravitation. The arguments suggesting that 'antigravity' could occur for antimatter and could even be expected in General Relativity itself are summarized. Experimental tests are proposed. (author). 48 refs

Testing the discreteness of spacetime at low energies

Energy Technology Data Exchange (ETDEWEB)

Chardin, G. [CEA Centre d`Etudes de Saclay, 91 - Gif-sur-Yvette (France). Dept. d`Astrophysique, de la Physique des Particules, de la Physique Nucleaire et de l`Instrumentation Associee

1994-12-31

Expected at the Planck scale, the discreteness of spacetime can hardly be tested at such high energies in a foreseable future. However, the Bekenstein relation suggests another approach, based on the study of time-asymmetry. After a brief introduction to discrete physics, the relation between gravitation and discreteness on the one hand, and between gravitation and time-asymmetry on the other was investigated. These relations have led to reconsider the possibility that CP violation in the neutral kaon system, the only known microscopic `arrow of time`, could be attributed to gravitation. The arguments suggesting that `antigravity` could occur for antimatter and could even be expected in General Relativity itself are summarized. Experimental tests are proposed. (author). 48 refs.

Lyapunov spectrum of the separated flow around the NACA 0012 airfoil and its dependence on numerical discretization

International Nuclear Information System (INIS)

Fernandez, P.; Wang, Q.

2017-01-01

We investigate the impact of numerical discretization on the Lyapunov spectrum of separated flow simulations. The two-dimensional chaotic flow around the NACA 0012 airfoil at a low Reynolds number and large angle of attack is considered to that end. Time, space and accuracy-order refinement studies are performed to examine each of these effects separately. Numerical results show that the time discretization has a small impact on the dynamics of the system, whereas the spatial discretization can dramatically change them. Also, the finite-time Lyapunov exponents associated to unstable modes are shown to be positively skewed, and quasi-homoclinic tangencies are observed in the attractor of the system. The implications of these results on flow physics and sensitivity analysis of chaotic flows are discussed.

Lyapunov spectrum of the separated flow around the NACA 0012 airfoil and its dependence on numerical discretization

Science.gov (United States)

Fernandez, P.; Wang, Q.

2017-12-01

We investigate the impact of numerical discretization on the Lyapunov spectrum of separated flow simulations. The two-dimensional chaotic flow around the NACA 0012 airfoil at a low Reynolds number and large angle of attack is considered to that end. Time, space and accuracy-order refinement studies are performed to examine each of these effects separately. Numerical results show that the time discretization has a small impact on the dynamics of the system, whereas the spatial discretization can dramatically change them. Also, the finite-time Lyapunov exponents associated to unstable modes are shown to be positively skewed, and quasi-homoclinic tangencies are observed in the attractor of the system. The implications of these results on flow physics and sensitivity analysis of chaotic flows are discussed.

On the discrete spectrum of non-self-adjoint Schroedinger differential equation with an operator coefficient

International Nuclear Information System (INIS)

Bayramoglu, Mehmet; Tasci, Fatih; Zeynalov, Djafar

2004-01-01

We study the discrete part of spectrum of a singular non-self-adjoint second-order differential equation on a semiaxis with an operator coefficient. Its boundedness is proved. The result is applied to the Schroedinger boundary value problem -Δu+q(x)u=λ 2 u, u vertical bar ∂D =0, with a complex potential q(x) in an angular domain

Low energy nuclear reactions driven by discrete breathers

OpenAIRE

Dubinko, Vladimir

2014-01-01

A new mechanism of LENR in solids is proposed, which is based on the large amplitude anharmonic lattice vibrations, a.k.a. intrinsic localized modes or discrete breathers (DBs). In particular, so called gap DBs, which can arise in diatomic crystals such as metal hydrides, are argued to be the LENR catalyzers. The large mass difference between H or D and the metal atoms provides a gap in phonon spectrum, in which DBs can be excited in the H/D sub-lattice resulting in extreme dynamic closing of...

Histogram plots and cutoff energies for nuclear discrete levels

International Nuclear Information System (INIS)

Belgya, T.; Molnar, G.; Fazekas, B.; Oestoer, J.

1997-05-01

Discrete level schemes for 1277 nuclei, from 6 Li through 251 Es, extracted from the Evaluated Nuclear Structure Data File were analyzed. Cutoff energies (U max ), indicating the upper limit of level scheme completeness, were deduced from the inspection of histograms of the cumulative number of levels. Parameters of the constant-temperature level density formula (nuclear temperature T and energy shift U 0 ) were obtained by means of the least square fit of the formula to the known levels below cutoff energy. The results are tabulated for all 1277 nuclei allowing for an easy and reliable application of the constant-temperature level density approach. A complete set of cumulative plots of discrete levels is also provided. (author). 5 figs, 2 tabs

Low-frequency logarithmic discretization of the reservoir spectrum for improving the efficiency of hierarchical equations of motion approach.

Science.gov (United States)

Ye, LvZhou; Zhang, Hou-Dao; Wang, Yao; Zheng, Xiao; Yan, YiJing

2017-08-21

An efficient low-frequency logarithmic discretization (LFLD) scheme for the decomposition of fermionic reservoir spectrum is proposed for the investigation of quantum impurity systems. The scheme combines the Padé spectrum decomposition (PSD) and a logarithmic discretization of the residual part in which the parameters are determined based on an extension of the recently developed minimum-dissipaton ansatz [J. J. Ding et al., J. Chem. Phys. 145, 204110 (2016)]. A hierarchical equations of motion (HEOM) approach is then employed to validate the proposed scheme by examining the static and dynamic system properties in both the Kondo and noninteracting regimes. The LFLD scheme requires a much smaller number of exponential functions than the conventional PSD scheme to reproduce the reservoir correlation function and thus facilitates the efficient implementation of the HEOM approach in extremely low temperature regimes.

Energy spectrum of buoyancy-driven turbulence

KAUST Repository

Kumar, Abhishek

2014-08-25

Using high-resolution direct numerical simulation and arguments based on the kinetic energy flux Πu, we demonstrate that, for stably stratified flows, the kinetic energy spectrum Eu(k)∼k-11/5, the potential energy spectrum Eθ(k)∼k-7/5, and Πu(k)∼k-4/5 are consistent with the Bolgiano-Obukhov scaling. This scaling arises due to the conversion of kinetic energy to the potential energy by buoyancy. For weaker buoyancy, this conversion is weak, hence Eu(k) follows Kolmogorov\\'s spectrum with a constant energy flux. For Rayleigh-Bénard convection, we show that the energy supply rate by buoyancy is positive, which leads to an increasing Πu(k) with k, thus ruling out Bolgiano-Obukhov scaling for the convective turbulence. Our numerical results show that convective turbulence for unit Prandt number exhibits a constant Πu(k) and Eu(k)∼k-5/3 for a narrow band of wave numbers. © 2014 American Physical Society.

Determination of central q and effective mass on textor based on discrete Alfven wave (DAW) spectrum measurements

International Nuclear Information System (INIS)

Descamps, P.; Wassenhove, G. van; Koch, R.; Messiaen, A.M.; Vandenplas, P.E.; Lister, J.B.; Marmillod, P.

1990-01-01

The use of the discrete Alfven wave spectrum to determine the current density profile and the effective mass density of the plasma in the TEXTOR tokamak is studied; the measurement, the validity of which is discussed, confirms independently the central q(r=0)<1 already obtained by polarimetry. (orig.)

Analytical energy spectrum for hybrid mechanical systems

International Nuclear Information System (INIS)

Zhong, Honghua; Xie, Qiongtao; Lee, Chaohong; Guan, Xiwen; Gao, Kelin; Batchelor, Murray T

2014-01-01

We investigate the energy spectrum for hybrid mechanical systems described by non-parity-symmetric quantum Rabi models. A set of analytical solutions in terms of the confluent Heun functions and their analytical energy spectrum is obtained. The analytical energy spectrum includes regular and exceptional parts, which are both confirmed by direct numerical simulation. The regular part is determined by the zeros of the Wronskian for a pair of analytical solutions. The exceptional part is relevant to the isolated exact solutions and its energy eigenvalues are obtained by analyzing the truncation conditions for the confluent Heun functions. By analyzing the energy eigenvalues for exceptional points, we obtain the analytical conditions for the energy-level crossings, which correspond to two-fold energy degeneracy. (paper)

Discrete gradients in discrete classical mechanics

International Nuclear Information System (INIS)

Renna, L.

1987-01-01

A simple model of discrete classical mechanics is given where, starting from the continuous Hamilton equations, discrete equations of motion are established together with a proper discrete gradient definition. The conservation laws of the total discrete momentum, angular momentum, and energy are demonstrated

Thermodynamic modeling, energy equipartition, and nonconservation of entropy for discrete-time dynamical systems

Directory of Open Access Journals (Sweden)

Chellaboina Vijaysekhar

2005-01-01

Full Text Available We develop thermodynamic models for discrete-time large-scale dynamical systems. Specifically, using compartmental dynamical system theory, we develop energy flow models possessing energy conservation, energy equipartition, temperature equipartition, and entropy nonconservation principles for discrete-time, large-scale dynamical systems. Furthermore, we introduce a new and dual notion to entropy; namely, ectropy, as a measure of the tendency of a dynamical system to do useful work and grow more organized, and show that conservation of energy in an isolated thermodynamic system necessarily leads to nonconservation of ectropy and entropy. In addition, using the system ectropy as a Lyapunov function candidate, we show that our discrete-time, large-scale thermodynamic energy flow model has convergent trajectories to Lyapunov stable equilibria determined by the system initial subsystem energies.

Discrete event simulations for glycolysis pathway and energy balance

NARCIS (Netherlands)

Zwieten, van D.A.J.; Rooda, J.E.; Armbruster, H.D.; Nagy, J.D.

2010-01-01

In this report, the biological network of the glycolysis pathway has been modeled using discrete event models (DEMs). The most important feature of this pathway is that energy is released. To create a stable steady-state system an energy molecule equilibrating enzyme and metabolic reactions have

On the spectrum of the one-speed slab-geometry discrete ordinates operator in neutron transport theory

International Nuclear Information System (INIS)

Abreu, Marcos Pimenta de

1998-01-01

We describe a numerical method applied to the first-order form of one-speed slab-geometry discrete ordinates equations modelling time-independent neutron transport problems with anisotropic scattering, with no interior source and defined in a nonmultiplying homogeneous host medium. Our numerical method is concerned with the generation of the spectrum and of a vector basis for the null space of the one-speed slab-geometry discrete ordinates operator. Moreover, it allows us to overcome the difficulties introduced in previous methods by anisotropic scattering and by angular quadrature sets of high order. To illustrate the positive features of our numerical method, we present numerical results for one-speed slab-geometry neutron transport model problems with anisotropic scattering

Relating zeta functions of discrete and quantum graphs

Science.gov (United States)

Harrison, Jonathan; Weyand, Tracy

2018-02-01

We write the spectral zeta function of the Laplace operator on an equilateral metric graph in terms of the spectral zeta function of the normalized Laplace operator on the corresponding discrete graph. To do this, we apply a relation between the spectrum of the Laplacian on a discrete graph and that of the Laplacian on an equilateral metric graph. As a by-product, we determine how the multiplicity of eigenvalues of the quantum graph, that are also in the spectrum of the graph with Dirichlet conditions at the vertices, depends on the graph geometry. Finally we apply the result to calculate the vacuum energy and spectral determinant of a complete bipartite graph and compare our results with those for a star graph, a graph in which all vertices are connected to a central vertex by a single edge.

Resource management for energy and spectrum harvesting sensor networks

CERN Document Server

Zhang, Deyu; Zhou, Haibo; Shen, Xuemin (Sherman)

2017-01-01

This SpringerBrief offers a comprehensive review and in-depth discussion of the current research on resource management. The authors explain how to best utilize harvested energy and temporally available licensed spectrum. Throughout the brief, the primary focus is energy and spectrum harvesting sensor networks (ESHNs) including energy harvesting (EH)-powered spectrum sensing and dynamic spectrum access. To efficiently collect data through the available licensed spectrum, this brief examines the joint management of energy and spectrum. An EH-powered spectrum sensing and management scheme for Heterogeneous Spectrum Harvesting Sensor Networks (HSHSNs) is presented in this brief. The scheme dynamically schedules the data sensing and spectrum access of sensors in ESHSNs to optimize the network utility, while considering the stochastic nature of EH process, PU activities and channel conditions. This brief also provides useful insights for the practical resource management scheme design for ESHSNs and motivates a ne...

Probing Efimov discrete scaling in an atom-molecule collision

Science.gov (United States)

Shalchi, M. A.; Yamashita, M. T.; Hadizadeh, M. R.; Garrido, E.; Tomio, Lauro; Frederico, T.

2018-01-01

The discrete Efimov scaling behavior, well known in the low-energy spectrum of three-body bound systems for large scattering lengths (unitary limit), is identified in the energy dependence of an atom-molecule elastic cross section in mass-imbalanced systems. That happens in the collision of a heavy atom with mass mH with a weakly bound dimer formed by the heavy atom and a lighter one with mass mL≪mH . Approaching the heavy-light unitary limit, the s -wave elastic cross section σ will present a sequence of zeros or minima at collision energies following closely the Efimov geometrical law. Our results, obtained with Faddeev calculations and supplemented by a Born-Oppenheimer analysis, open a perspective to detecting the discrete scaling behavior from low-energy scattering data, which is timely in view of the ongoing experiments with ultracold binary mixtures having strong mass asymmetries, such as lithium and cesium or lithium and ytterbium.

Multiple discrete-energy ion features in the inner magnetosphere: 9 February 1998, event

Directory of Open Access Journals (Sweden)

Y. Ebihara

2004-04-01

Full Text Available Multiple discrete-energy ion bands observed by the Polar satellite in the inner magnetosphere on 9 February 1998 were investigated by means of particle simulation with a realistic model of the convection electric field. The multiple bands appeared in the energy vs. L spectrum in the 1–100 keV range when Polar traveled in the heart of the ring current along the outbound and inbound paths. We performed particle tracing, and simulated the energy vs. L spectra of proton fluxes under the dipole magnetic field, the corotation electric field, and the realistic convection electric field model with its parameters depending on the solar wind data. Simulated spectra are shown to agree well with the observed ones. A better agreement is achieved when we rotate the convection electric potential eastward by 2h inMLT and we change the distribution function in time in the near-Earth magnetotail. It is concluded that the multiple bands are likely produced by two processes for this particular event, that is, changes in the convection electric field (for >3keV protons and changes in the distribution function in the near-Earth magnetotail (for <3keV protons. Key words. Magnetospheric physics (energetic particles, trapped; electric field – Space plasma physics (numerical simulation studies

Discrete Ramanujan transform for distinguishing the protein coding regions from other regions.

Science.gov (United States)

Hua, Wei; Wang, Jiasong; Zhao, Jian

2014-01-01

Based on the study of Ramanujan sum and Ramanujan coefficient, this paper suggests the concepts of discrete Ramanujan transform and spectrum. Using Voss numerical representation, one maps a symbolic DNA strand as a numerical DNA sequence, and deduces the discrete Ramanujan spectrum of the numerical DNA sequence. It is well known that of discrete Fourier power spectrum of protein coding sequence has an important feature of 3-base periodicity, which is widely used for DNA sequence analysis by the technique of discrete Fourier transform. It is performed by testing the signal-to-noise ratio at frequency N/3 as a criterion for the analysis, where N is the length of the sequence. The results presented in this paper show that the property of 3-base periodicity can be only identified as a prominent spike of the discrete Ramanujan spectrum at period 3 for the protein coding regions. The signal-to-noise ratio for discrete Ramanujan spectrum is defined for numerical measurement. Therefore, the discrete Ramanujan spectrum and the signal-to-noise ratio of a DNA sequence can be used for distinguishing the protein coding regions from the noncoding regions. All the exon and intron sequences in whole chromosomes 1, 2, 3 and 4 of Caenorhabditis elegans have been tested and the histograms and tables from the computational results illustrate the reliability of our method. In addition, we have analyzed theoretically and gotten the conclusion that the algorithm for calculating discrete Ramanujan spectrum owns the lower computational complexity and higher computational accuracy. The computational experiments show that the technique by using discrete Ramanujan spectrum for classifying different DNA sequences is a fast and effective method. Copyright © 2014 Elsevier Ltd. All rights reserved.

Dynamic energy spectrum and energy deposition in solid target by intense pulsed ion beams

Institute of Scientific and Technical Information of China (English)

Xiao Yu; Xiao-Yun Le; Zheng Liu; Jie Shen; Yu I.Isakova; Hao-Wen Zhong; Jie Zhang; Sha Yan; Gao-Long Zhang; Xiao-Fu Zhang

2017-01-01

A method for analyzing the dynamic energy spectrum of intense pulsed ion beam (IPIB) was proposed.Its influence on beam energy deposition in metal target was studied with IPIB produced by two types of magnetically insulated diodes (MID).The emission of IPIB was described with space charge limitation model,and the dynamic energy spectrum was further analyzed with time-of-flight method.IPIBs generated by pulsed accelerators of BIPPAB-450 (active MID) and TEMP-4M (passive MID) were studied.The dynamic energy spectrum was used to deduce the power density distribution of IPIB in the target with Monte Carlo simulation and infrared imaging diagnostics.The effect on the distribution and evolution of thermal field induced by the characteristics of IPIB dynamic energy spectrum was discussed.

Energy transfer, orbital angular momentum, and discrete current in a double-ring fiber array

International Nuclear Information System (INIS)

Alexeyev, C. N.; Volyar, A. V.; Yavorsky, M. A.

2011-01-01

We study energy transfer and orbital angular momentum of supermodes in a double-ring array of evanescently coupled monomode optical fibers. The structure of supermodes and the spectra of their propagation constants are obtained. The geometrical parameters of the array, at which the energy is mostly confined within the layers, are determined. The developed method for finding the supermodes of concentric arrays is generalized for the case of multiring arrays. The orbital angular momentum carried by a supermode of a double-ring array is calculated. The discrete lattice current is introduced. It is shown that the sum of discrete currents over the array is a conserved quantity. The connection of the total discrete current with orbital angular momentum of discrete optical vortices is made.

Energy transfer, orbital angular momentum, and discrete current in a double-ring fiber array

Energy Technology Data Exchange (ETDEWEB)

Alexeyev, C. N.; Volyar, A. V. [Taurida National V.I. Vernadsky University, Vernadsky Prospekt, 4, Simferopol, 95007, Crimea (Ukraine); Yavorsky, M. A. [Taurida National V.I. Vernadsky University, Vernadsky Prospekt, 4, Simferopol, 95007, Crimea (Ukraine); Universite Bordeaux and CNRS, LOMA, UMR 5798, FR-33400 Talence (France)

2011-12-15

We study energy transfer and orbital angular momentum of supermodes in a double-ring array of evanescently coupled monomode optical fibers. The structure of supermodes and the spectra of their propagation constants are obtained. The geometrical parameters of the array, at which the energy is mostly confined within the layers, are determined. The developed method for finding the supermodes of concentric arrays is generalized for the case of multiring arrays. The orbital angular momentum carried by a supermode of a double-ring array is calculated. The discrete lattice current is introduced. It is shown that the sum of discrete currents over the array is a conserved quantity. The connection of the total discrete current with orbital angular momentum of discrete optical vortices is made.

Electron energy spectrum in core-shell elliptic quantum wire

Directory of Open Access Journals (Sweden)

V.Holovatsky

2007-01-01

Full Text Available The electron energy spectrum in core-shell elliptic quantum wire and elliptic semiconductor nanotubes are investigated within the effective mass approximation. The solution of Schrodinger equation based on the Mathieu functions is obtained in elliptic coordinates. The dependencies of the electron size quantization spectrum on the size and shape of the core-shell nanowire and nanotube are calculated. It is shown that the ellipticity of a quantum wire leads to break of degeneration of quasiparticle energy spectrum. The dependences of the energy of odd and even electron states on the ratio between semiaxes are of a nonmonotonous character. The anticrosing effects are observed at the dependencies of electron energy spectrum on the transversal size of the core-shell nanowire.

Energy Stability Analysis of Some Fully Discrete Numerical Schemes for Incompressible Navier–Stokes Equations on Staggered Grids

KAUST Repository

Chen, Huangxin

2017-09-01

In this paper we consider the energy stability estimates for some fully discrete schemes which both consider time and spatial discretizations for the incompressible Navier–Stokes equations. We focus on three kinds of fully discrete schemes, i.e., the linear implicit scheme for time discretization with the finite difference method (FDM) on staggered grids for spatial discretization, pressure-correction schemes for time discretization with the FDM on staggered grids for the solutions of the decoupled velocity and pressure equations, and pressure-stabilization schemes for time discretization with the FDM on staggered grids for the solutions of the decoupled velocity and pressure equations. The energy stability estimates are obtained for the above each fully discrete scheme. The upwind scheme is used in the discretization of the convection term which plays an important role in the design of unconditionally stable discrete schemes. Numerical results are given to verify the theoretical analysis.

Discrete Hilbert transformation and its application to estimate the wind speed in Hong Kong

Energy Technology Data Exchange (ETDEWEB)

Zhu, Zuojin [Department of Thermal Science and Energy Engineering, Institute of Engineering Science, University of Science and Technology of China, Hefei, Anhui (China); Yang, Hongxing [Department of Building Services Engineering, The Hong Kong Polytechnic University, Hong Kong (Hong Kong)

2002-01-01

Discrete Hilbert Transform (DHT) has been applied to estimate the wind speed with the sample data sequence selected from the data record observed by the observatory in Hong Kong in June 1989, during which the data pertain to deep valleys and sharp crests due to manifold weather conditions in this region. To confirm the performance of the discrete Hilbert transformer, two harmonic input sequences were used to inspect the output signals, whether good agreement with the theoretical results is obtained. It was found that the energy spectrum and the outputs for the two different harmonic discrete waves are certainly correct. After the inspection of the DHT filter, the sample data for wind speed in Hong Kong were used for wind speed forecasting. For zero mean input sequence, the variance of the output is the same as that of the input signals, and so is the energy spectrum. The DHT of an individual input sample can really reflect the local variation performance, since it is the convolution with the reciprocal of time and the input data sequence, but there exists phase shift. For harmonic signals, the output signal holds a 90 phase delay.

Energy spectrum control for modulated proton beams

International Nuclear Information System (INIS)

Hsi, Wen C.; Moyers, Michael F.; Nichiporov, Dmitri; Anferov, Vladimir; Wolanski, Mark; Allgower, Chris E.; Farr, Jonathan B.; Mascia, Anthony E.; Schreuder, Andries N.

2009-01-01

In proton therapy delivered with range modulated beams, the energy spectrum of protons entering the delivery nozzle can affect the dose uniformity within the target region and the dose gradient around its periphery. For a cyclotron with a fixed extraction energy, a rangeshifter is used to change the energy but this produces increasing energy spreads for decreasing energies. This study investigated the magnitude of the effects of different energy spreads on dose uniformity and distal edge dose gradient and determined the limits for controlling the incident spectrum. A multilayer Faraday cup (MLFC) was calibrated against depth dose curves measured in water for nonmodulated beams with various incident spectra. Depth dose curves were measured in a water phantom and in a multilayer ionization chamber detector for modulated beams using different incident energy spreads. Some nozzle entrance energy spectra can produce unacceptable dose nonuniformities of up to ±21% over the modulated region. For modulated beams and small beam ranges, the width of the distal penumbra can vary by a factor of 2.5. When the energy spread was controlled within the defined limits, the dose nonuniformity was less than ±3%. To facilitate understanding of the results, the data were compared to the measured and Monte Carlo calculated data from a variable extraction energy synchrotron which has a narrow spectrum for all energies. Dose uniformity is only maintained within prescription limits when the energy spread is controlled. At low energies, a large spread can be beneficial for extending the energy range at which a single range modulator device can be used. An MLFC can be used as part of a feedback to provide specified energy spreads for different energies.

Knowledge network model of the energy consumption in discrete manufacturing system

Science.gov (United States)

Xu, Binzi; Wang, Yan; Ji, Zhicheng

2017-07-01

Discrete manufacturing system generates a large amount of data and information because of the development of information technology. Hence, a management mechanism is urgently required. In order to incorporate knowledge generated from manufacturing data and production experience, a knowledge network model of the energy consumption in the discrete manufacturing system was put forward based on knowledge network theory and multi-granularity modular ontology technology. This model could provide a standard representation for concepts, terms and their relationships, which could be understood by both human and computer. Besides, the formal description of energy consumption knowledge elements (ECKEs) in the knowledge network was also given. Finally, an application example was used to verify the feasibility of the proposed method.

A discrete wavelet spectrum approach for identifying non-monotonic trends in hydroclimate data

Science.gov (United States)

Sang, Yan-Fang; Sun, Fubao; Singh, Vijay P.; Xie, Ping; Sun, Jian

2018-01-01

The hydroclimatic process is changing non-monotonically and identifying its trends is a great challenge. Building on the discrete wavelet transform theory, we developed a discrete wavelet spectrum (DWS) approach for identifying non-monotonic trends in hydroclimate time series and evaluating their statistical significance. After validating the DWS approach using two typical synthetic time series, we examined annual temperature and potential evaporation over China from 1961-2013 and found that the DWS approach detected both the warming and the warming hiatus in temperature, and the reversed changes in potential evaporation. Further, the identified non-monotonic trends showed stable significance when the time series was longer than 30 years or so (i.e. the widely defined climate timescale). The significance of trends in potential evaporation measured at 150 stations in China, with an obvious non-monotonic trend, was underestimated and was not detected by the Mann-Kendall test. Comparatively, the DWS approach overcame the problem and detected those significant non-monotonic trends at 380 stations, which helped understand and interpret the spatiotemporal variability in the hydroclimatic process. Our results suggest that non-monotonic trends of hydroclimate time series and their significance should be carefully identified, and the DWS approach proposed has the potential for wide use in the hydrological and climate sciences.

Wave Equation for Operators with Discrete Spectrum and Irregular Propagation Speed

Science.gov (United States)

Ruzhansky, Michael; Tokmagambetov, Niyaz

2017-12-01

Given a Hilbert space H, we investigate the well-posedness of the Cauchy problem for the wave equation for operators with a discrete non-negative spectrum acting on H. We consider the cases when the time-dependent propagation speed is regular, Hölder, and distributional. We also consider cases when it is strictly positive (strictly hyperbolic case) and when it is non-negative (weakly hyperbolic case). When the propagation speed is a distribution, we introduce the notion of "very weak solutions" to the Cauchy problem. We show that the Cauchy problem for the wave equation with the distributional coefficient has a unique "very weak solution" in an appropriate sense, which coincides with classical or distributional solutions when the latter exist. Examples include the harmonic and anharmonic oscillators, the Landau Hamiltonian on {R^n}, uniformly elliptic operators of different orders on domains, Hörmander's sums of squares on compact Lie groups and compact manifolds, operators on manifolds with boundary, and many others.

Mass, momentum and energy conserving (MaMEC) discretizations on general grids for the compressible Euler and shallow water equations

International Nuclear Information System (INIS)

Hof, Bas van’t; Veldman, Arthur E.P.

2012-01-01

The paper explains a method by which discretizations of the continuity and momentum equations can be designed, such that they can be combined with an equation of state into a discrete energy equation. The resulting ‘MaMEC’ discretizations conserve mass, momentum as well as energy, although no explicit conservation law for the total energy is present. Essential ingredients are (i) discrete convection that leaves the discrete energy invariant, and (ii) discrete consistency between the thermodynamic terms. Of particular relevance is the way in which finite volume fluxes are related to nodal values. The method is an extension of existing methods based on skew-symmetry of discrete operators, because it allows arbitrary equations of state and a larger class of grids than earlier methods. The method is first illustrated with a one-dimensional example on a highly stretched staggered grid, in which the MaMEC method calculates qualitatively correct results and a non-skew-symmetric finite volume method becomes unstable. A further example is a two-dimensional shallow water calculation on a rectilinear grid as well as on an unstructured grid. The conservation of mass, momentum and energy is checked, and losses are found negligible up to machine accuracy.

Discrete Planck spectra

International Nuclear Information System (INIS)

Vlad, Valentin I.; Ionescu-Pallas, Nicholas

2000-10-01

The Planck radiation spectrum of ideal cubic and spherical cavities, in the region of small adiabatic invariance, γ = TV 1/3 , is shown to be discrete and strongly dependent on the cavity geometry and temperature. This behavior is the consequence of the random distribution of the state weights in the cubic cavity and of the random overlapping of the successive multiplet components, for the spherical cavity. The total energy (obtained by summing up the exact contributions of the eigenvalues and their weights, for low values of the adiabatic invariance) does not obey any longer Stefan-Boltzmann law. The new law includes a corrective factor depending on γ and imposes a faster decrease of the total energy to zero, for γ → 0. We have defined the double quantized regime both for cubic and spherical cavities by the superior and inferior limits put on the principal quantum numbers or the adiabatic invariance. The total energy of the double quantized cavities shows large differences from the classical calculations over unexpected large intervals, which are measurable and put in evidence important macroscopic quantum effects. (author)

Mass, momentum and energy conserving (MaMEC) discretizations on general grids for the compressible Euler and shallow water equations

NARCIS (Netherlands)

Hof, Bas van ’t; Veldman, Arthur E.P.

2012-01-01

The paper explains a method by which discretizations of the continuity and momentum equations can be designed, such that they can be combined with an equation of state into a discrete energy equation. The resulting 'MaMEC' discretizations conserve mass, momentum as well as energy, although no

Energy Stability Analysis of Some Fully Discrete Numerical Schemes for Incompressible Navier–Stokes Equations on Staggered Grids

KAUST Repository

Chen, Huangxin; Sun, Shuyu; Zhang, Tao

2017-01-01

In this paper we consider the energy stability estimates for some fully discrete schemes which both consider time and spatial discretizations for the incompressible Navier–Stokes equations. We focus on three kinds of fully discrete schemes, i

A discrete wavelet spectrum approach for identifying non-monotonic trends in hydroclimate data

Directory of Open Access Journals (Sweden)

Y.-F. Sang

2018-01-01

Full Text Available The hydroclimatic process is changing non-monotonically and identifying its trends is a great challenge. Building on the discrete wavelet transform theory, we developed a discrete wavelet spectrum (DWS approach for identifying non-monotonic trends in hydroclimate time series and evaluating their statistical significance. After validating the DWS approach using two typical synthetic time series, we examined annual temperature and potential evaporation over China from 1961–2013 and found that the DWS approach detected both the warming and the warming hiatus in temperature, and the reversed changes in potential evaporation. Further, the identified non-monotonic trends showed stable significance when the time series was longer than 30 years or so (i.e. the widely defined climate timescale. The significance of trends in potential evaporation measured at 150 stations in China, with an obvious non-monotonic trend, was underestimated and was not detected by the Mann–Kendall test. Comparatively, the DWS approach overcame the problem and detected those significant non-monotonic trends at 380 stations, which helped understand and interpret the spatiotemporal variability in the hydroclimatic process. Our results suggest that non-monotonic trends of hydroclimate time series and their significance should be carefully identified, and the DWS approach proposed has the potential for wide use in the hydrological and climate sciences.

Full Spectrum Diffused and Beamed Solar Energy Application Using Optical Fibre

OpenAIRE

Majumdar, M. R. Dutta; Das, Debasish

2007-01-01

Existing solar energy application systems use small fraction of full spectrum of solar energy. So attempts are made to show how full spectrum solar energy can be used for diffused and beamed form of incident solar energy. Luminescent Solar Concentrator (LSC) principle with optical fibre in diffused sun light and dielectric mirror separation technique with optical fibre in beamed form are discussed. Comparison of both the cases are done. Keywords: full spectrum, solar photonics, diffused solar...

Energy spectrum and angular distribution of prompt cosmic-ray muons

Energy Technology Data Exchange (ETDEWEB)

Castagnoli, C; Picchi, P [Consiglio Nazionale delle Ricerche, Turin (Italy). Lab. di Cosmo-Geofisica; Turin Univ. (Italy). Ist. di Fisica Generale); Castellina, A; D' Ettorre Piazzoli, B; Mannocchi, G; Vernetto, S [Consiglio Nazionale delle Ricerche, Turin (Italy). Lab. di Cosmo-Geofisica

1984-07-01

The energy spectrum and angular distribution of atmospheric prompt muons are calculated by using an integral solution for production of charmed particles, their decay and muon transport in the atmosphere. Current experimental information from accelerator and theoretical ideas about charm cross-section and semi-leptonic decay are used to give a reference prompt muon spectrum to compare with that from conventional sources (..pi.. and K decay). The obtained differential spectrum has an energy dependence which approaches that of the primary cosmic rays. The integral intensity of prompt muons is equal to the conventional one at about 250 TeV. The angular distribution is found to be practically flat in the range (0/80)/sup 0/ irrespective of the muon energy. On the basis of this analysis we estimate that accurate measurements of muon energy spectrum and angular distribution at energies greater than 10 TeV should allow one to obtain useful information regarding charm hadroproduction cross-section in the 100 TeV region.

"Minesweeper" and spectrum of discrete Laplacians

OpenAIRE

German, Oleg; Lakshtanov, Evgeny

2008-01-01

The paper is devoted to a problem inspired by the "Minesweeper" computer game. It is shown that certain configurations of open cells guarantee the existence and the uniqueness of solution. Mathematically the problem is reduced to some spectral properties of discrete differential operators. It is shown how the uniqueness can be used to create a new game which preserves the spirit of "Minesweeper" but does not require a computer.

Condensing Raman spectrum for single-cell phenotype analysis

KAUST Repository

Sun, Shiwei; Wang, Xuetao; Gao, Xin; Ren, Lihui; Su, Xiaoquan; Bu, Dongbo; Ning, Kang

2015-01-01

In this work, we have proposed an approach called rDisc to discretize the original Raman spectrum into only a few (usually less than 20) representative peaks (Raman shifts). The approach has advantages in removing noises, and condensing the original spectrum. In particular, effective signal processing procedures were designed to eliminate noise, utilising wavelet transform denoising, baseline correction, and signal normalization. In the discretizing process, representative peaks were selected to signicantly decrease the Raman data size. More importantly, the selected peaks are chosen as suitable to serve as key biological markers to differentiate species and other cellular features. Additionally, the classication performance of discretized spectra was found to be comparable to full spectrum having more than 1000 Raman shifts. Overall, the discretized spectrum needs about 5storage space of a full spectrum and the processing speed is considerably faster. This makes rDisc clearly superior to other methods for single-cell classication.

Energy spectrum of lightning gamma emission

Energy Technology Data Exchange (ETDEWEB)

Chubenko, A.P. [P.N. Lebedev Physical Institute of RAS, Moscow (Russian Federation); Karashtin, A.N. [Research Radiophysics Institute, Nizhny Novgorod (Russian Federation); Ryabov, V.A., E-mail: ryabov@x4u.lebedev.r [P.N. Lebedev Physical Institute of RAS, Moscow (Russian Federation); Shepetov, A.L. [P.N. Lebedev Physical Institute of RAS, Moscow (Russian Federation); Antonova, V.P.; Kryukov, S.V. [Ionosphere Institute, Almaty (Kazakhstan); Mitko, G.G.; Naumov, A.S.; Pavljuchenko, L.V. [P.N. Lebedev Physical Institute of RAS, Moscow (Russian Federation); Ptitsyn, M.O., E-mail: ptitsyn@lpi.r [P.N. Lebedev Physical Institute of RAS, Moscow (Russian Federation); Shalamova, S.Ya. [P.N. Lebedev Physical Institute of RAS, Moscow (Russian Federation); Shlyugaev, Yu.V. [Research Radiophysics Institute, Nizhny Novgorod (Russian Federation); Vildanova, L.I. [Tien-Shan Mountain Cosmic Ray Station, Almaty (Kazakhstan); Zybin, K.P. [P.N. Lebedev Physical Institute of RAS, Moscow (Russian Federation); Gurevich, A.V., E-mail: alex@lpi.r [P.N. Lebedev Physical Institute of RAS, Moscow (Russian Federation)

2009-08-10

The results of gamma emission observations obtained during thunderstorms at Tien-Shan Mountain Cosmic Ray Station are presented. The energy spectrum radiation of the stepped leader gamma radiation is measured. The total energy of stepped leader emitted in gamma rays is estimated as 10{sup -3}-10{sup -2} J. The experimental results are in an agreement with the runaway breakdown mechanism.

Energy spectrum of lightning gamma emission

International Nuclear Information System (INIS)

Chubenko, A.P.; Karashtin, A.N.; Ryabov, V.A.; Shepetov, A.L.; Antonova, V.P.; Kryukov, S.V.; Mitko, G.G.; Naumov, A.S.; Pavljuchenko, L.V.; Ptitsyn, M.O.; Shalamova, S.Ya.; Shlyugaev, Yu.V.; Vildanova, L.I.; Zybin, K.P.; Gurevich, A.V.

2009-01-01

The results of gamma emission observations obtained during thunderstorms at Tien-Shan Mountain Cosmic Ray Station are presented. The energy spectrum radiation of the stepped leader gamma radiation is measured. The total energy of stepped leader emitted in gamma rays is estimated as 10 -3 -10 -2 J. The experimental results are in an agreement with the runaway breakdown mechanism.

Image compression-encryption algorithms by combining hyper-chaotic system with discrete fractional random transform

Science.gov (United States)

Gong, Lihua; Deng, Chengzhi; Pan, Shumin; Zhou, Nanrun

2018-07-01

Based on hyper-chaotic system and discrete fractional random transform, an image compression-encryption algorithm is designed. The original image is first transformed into a spectrum by the discrete cosine transform and the resulting spectrum is compressed according to the method of spectrum cutting. The random matrix of the discrete fractional random transform is controlled by a chaotic sequence originated from the high dimensional hyper-chaotic system. Then the compressed spectrum is encrypted by the discrete fractional random transform. The order of DFrRT and the parameters of the hyper-chaotic system are the main keys of this image compression and encryption algorithm. The proposed algorithm can compress and encrypt image signal, especially can encrypt multiple images once. To achieve the compression of multiple images, the images are transformed into spectra by the discrete cosine transform, and then the spectra are incised and spliced into a composite spectrum by Zigzag scanning. Simulation results demonstrate that the proposed image compression and encryption algorithm is of high security and good compression performance.

ON THE SPECTRUM OF THE ONE-DIMENSIONAL SCHRÖDINGER HAMILTONIAN PERTURBED BY AN ATTRACTIVE GAUSSIAN POTENTIAL

Directory of Open Access Journals (Sweden)

Silvestro Fassari

2017-12-01

Full Text Available We propose a new approach to the problem of finding the eigenvalues (energy levels in the discrete spectrum of the one-dimensional Hamiltonian with an attractive Gaussian potential by using the well-known Birman-Schwinger technique. However, in place of the Birman-Schwinger integral operator we consider an isospectral operator in momentum space, taking advantage of the unique feature of this potential, that is to say its invariance under Fourier transform. Given that such integral operators are trace class, it is possible to determine the energy levels in the discrete spectrum of the Hamiltonian as functions of the coupling constant with great accuracy by solving a finite number of transcendental equations. We also address the important issue of the coupling constant thresholds of the Hamiltonian, that is to say the critical values of λ for which we have the emergence of an additional bound state out of the absolutely continuous spectrum. 

Energy spectrum structure and ''trap'' effects in a three-particle system

International Nuclear Information System (INIS)

Simenog, I.V.; Sitnichenko, A.I.

1982-01-01

Investigation is made of the threshold energy spectrum structure in a system of three spinless particles depending on the form of two-particle interaction. The correlation dependence of the spectrum and low-energy scattering parameters are shown. A new phenomenon of ''traps'' for the spectrum in a three-particle system with interaction involving components of considerably different ranges is established

Post-processing of EPR spectrum from dosimetric substances through filtering of Discrete Fourier Transform

International Nuclear Information System (INIS)

Vieira, Fabio P.B.; Bevilacqua, Joyce S.

2014-01-01

The use of electron paramagnetic resonance spectrometers - EPR - in radiation dosimetry is known for more than four decades. It is an important tool in the retrospective determination of doses absorbed. To estimate the dose absorbed by the sample, it is necessary to know the amplitude of the peak to peak signature of the substance in its EPR spectrum. This information can be compromised by the presence of spurious information: noise - of random and low intensity nature; and the behavior of the baseline - coming from the coupling between the resonator tube and the sample analyzed. Due to the intrinsic characteristics of the three main components of the signal, i.e. signature, noise, and baseline - the analysis in the frequency domain allows, through post-processing techniques to filter spurious information. In this work, an algorithm that retrieves the signature of a substance has been implemented. The Discrete Fourier Transform is applied to the signal and without user intervention, the noise is filtered. From the filtered signal, recovers the signature by Inverse Discrete Fourier Transform. The peak to peak amplitude, and the absorbed dose is calculated with an error of less than 1% for signals wherein the base line is linearized. Some more general cases are under investigation and with little user intervention, you can get the same error

Missing baryonic resonances in the Hagedorn spectrum

Energy Technology Data Exchange (ETDEWEB)

Man Lo, Pok [University of Wroclaw, Institute of Theoretical Physics, Wroclaw (Poland); GSI, Extreme Matter Institute EMMI, Darmstadt (Germany); Marczenko, Michal; Sasaki, Chihiro [University of Wroclaw, Institute of Theoretical Physics, Wroclaw (Poland); Redlich, Krzysztof [University of Wroclaw, Institute of Theoretical Physics, Wroclaw (Poland); GSI, Extreme Matter Institute EMMI, Darmstadt (Germany); Duke University, Department of Physics, Durham, NC (United States)

2016-08-15

The hadronic medium of QCD is modeled as a gas of point-like hadrons, with its composition determined by the Hagedorn mass spectrum. The spectrum consists of a discrete and a continuous part. The former is determined by the experimentally confirmed resonances tabulated by the Particle Data Group (PDG), while the latter can be extracted from the existing lattice data. This formulation of the hadron resonance gas (HRG) provides a transparent framework to relate the fluctuation of conserved charges as calculated in the lattice QCD approach to the particle content of the medium. A comparison of the two approaches shows that the equation of state is well described by the standard HRG model, which includes only a discrete spectrum of known hadrons. The corresponding description in the strange sector, however, shows clear discrepancies, thus a continuous spectrum is added to incorporate the effect of missing resonances. We propose a method to extract the strange-baryon spectrum from the lattice data. The result is consistent with the trend set by the unconfirmed strange baryons resonances listed by the PDG, suggesting that most of the missing interaction strength for the strange baryons reside in the S = 1 sector. This scenario is also supported by recent lattice calculations, and might be important in the energy region covered by the NICA accelerator in Dubna, where in the heavy-ion collisions, baryons are the dominating degrees of freedom in the final state. (orig.)

On the Energy Spectrum of Strong Magnetohydrodynamic Turbulence

Directory of Open Access Journals (Sweden)

Jean Carlos Perez

2012-10-01

Full Text Available The energy spectrum of magnetohydrodynamic turbulence attracts interest due to its fundamental importance and its relevance for interpreting astrophysical data. Here we present measurements of the energy spectra from a series of high-resolution direct numerical simulations of magnetohydrodynamics turbulence with a strong guide field and for increasing Reynolds number. The presented simulations, with numerical resolutions up to 2048^{3} mesh points and statistics accumulated over 30 to 150 eddy turnover times, constitute, to the best of our knowledge, the largest statistical sample of steady state magnetohydrodynamics turbulence to date. We study both the balanced case, where the energies associated with Alfvén modes propagating in opposite directions along the guide field, E^{+}(k_{⊥} and E^{-}(k_{⊥}, are equal, and the imbalanced case where the energies are different. In the balanced case, we find that the energy spectrum converges to a power law with exponent -3/2 as the Reynolds number is increased, which is consistent with phenomenological models that include scale-dependent dynamic alignment. For the imbalanced case, with E^{+}>E^{-}, the simulations show that E^{-}∝k_{⊥}^{-3/2} for all Reynolds numbers considered, while E^{+} has a slightly steeper spectrum at small Re. As the Reynolds number increases, E^{+} flattens. Since E^{±} are pinned at the dissipation scale and anchored at the driving scales, we postulate that at sufficiently high Re the spectra will become parallel in the inertial range and scale as E^{+}∝E^{-}∝k_{⊥}^{-3/2}. Questions regarding the universality of the spectrum and the value of the “Kolmogorov constant” are discussed.

Comparative study on γ energy spectrum denoise by fourier and wavelet transforms

International Nuclear Information System (INIS)

Shi Dongsheng; Di Yuming; Zhou Chunlin

2007-01-01

This paper introduces the basic principle of wavelet and Fourier transforms, applies wavelet transform method to denoise γ energy spectrum of 60 Co and compares it with Fourier transform method. The result of simulation with MATLAB software tool showed that as compared with traditional Fourier transform, wavelet transform has comparatively higher accuracy for γ energy spectrum denoising and is more feasible to γ energy spectrum denoising. (authors)

A fully discrete energy stable scheme for a phase filed moving contact line model with variable densities and viscosities

KAUST Repository

Zhu, Guangpu

2018-01-26

In this paper, a fully discrete scheme which considers temporal and spatial discretizations is presented for the coupled Cahn-Hilliard equation in conserved form with the dynamic contact line condition and the Navier-Stokes equation with the generalized Navier boundary condition. Variable densities and viscosities are incorporated in this model. A rigorous proof of energy stability is provided for the fully discrete scheme based on a semi-implicit temporal discretization and a finite difference method on the staggered grids for the spatial discretization. A splitting method based on the pressure stabilization is implemented to solve the Navier-Stokes equation, while the stabilization approach is also used for the Cahn-Hilliard equation. Numerical results in both 2-D and 3-D demonstrate the accuracy, efficiency and decaying property of discrete energy of the proposed scheme.

Discrete density of states

International Nuclear Information System (INIS)

Aydin, Alhun; Sisman, Altug

2016-01-01

By considering the quantum-mechanically minimum allowable energy interval, we exactly count number of states (NOS) and introduce discrete density of states (DOS) concept for a particle in a box for various dimensions. Expressions for bounded and unbounded continua are analytically recovered from discrete ones. Even though substantial fluctuations prevail in discrete DOS, they're almost completely flattened out after summation or integration operation. It's seen that relative errors of analytical expressions of bounded/unbounded continua rapidly decrease for high NOS values (weak confinement or high energy conditions), while the proposed analytical expressions based on Weyl's conjecture always preserve their lower error characteristic. - Highlights: • Discrete density of states considering minimum energy difference is proposed. • Analytical DOS and NOS formulas based on Weyl conjecture are given. • Discrete DOS and NOS functions are examined for various dimensions. • Relative errors of analytical formulas are much better than the conventional ones.

Critical excitation spectrum of a quantum chain with a local three-spin coupling.

Science.gov (United States)

McCabe, John F; Wydro, Tomasz

2011-09-01

Using the phenomenological renormalization group (PRG), we evaluate the low-energy excitation spectrum along the critical line of a quantum spin chain having a local interaction between three Ising spins and longitudinal and transverse magnetic fields, i.e., a Turban model. The low-energy excitation spectrum found with the PRG agrees with the spectrum predicted for the (D(4),A(4)) conformal minimal model under a nontrivial correspondence between translations at the critical line and discrete lattice translations. Under this correspondence, the measurements confirm a prediction that the critical line of this quantum spin chain and the critical point of the two-dimensional three-state Potts model are in the same universality class.

Critical excitation spectrum of a quantum chain with a local three-spin coupling

International Nuclear Information System (INIS)

McCabe, John F.; Wydro, Tomasz

2011-01-01

Using the phenomenological renormalization group (PRG), we evaluate the low-energy excitation spectrum along the critical line of a quantum spin chain having a local interaction between three Ising spins and longitudinal and transverse magnetic fields, i.e., a Turban model. The low-energy excitation spectrum found with the PRG agrees with the spectrum predicted for the (D 4 ,A 4 ) conformal minimal model under a nontrivial correspondence between translations at the critical line and discrete lattice translations. Under this correspondence, the measurements confirm a prediction that the critical line of this quantum spin chain and the critical point of the two-dimensional three-state Potts model are in the same universality class.

FACT. Energy spectrum of the Crab Nebula

Energy Technology Data Exchange (ETDEWEB)

Temme, Fabian; Einecke, Sabrina; Buss, Jens [TU Dortmund, Experimental Physics 5, Otto-Hahn-Str.4, 44221 Dortmund (Germany); Collaboration: FACT-Collaboration

2016-07-01

The First G-APD Cherenkov Telescope is the first Imaging Air Cherenkov Telescope which uses silicon photon detectors (G-APDs aka SiPM) as photo sensors. With more than four years of operation, FACT proved an application of SiPMs is suitable for the field of ground-based gamma-ray astronomy. Due to the stable flux at TeV energies, the Crab Nebula is handled as a ''standard candle'' in Cherenkov astronomy. The analysis of its energy spectrum and comparison with other experiments, allows to evaluate the performance of FACT. A modern analysis chain, based on data stream handling and multivariate analysis methods was developed in close cooperation with the department of computer science at the TU Dortmund. In this talk, this analysis chain and its application are presented. Further to this, results, including the energy spectrum of the Crab Nebula, measured with FACT, are shown.

Formation of a superhigh energy electron spectrum in the Galaxy

International Nuclear Information System (INIS)

Agaronyan, F.A.; Ambartsumyan, A.S.

1985-01-01

The formation of superhigh energy electron spectrum in the disk of the galaxy and halo is considered. A different behaviour of the electron spectrum within the framework of capture models in disk or halo, in the energy region E> or approximately 10 5 GeV is revealed due to the account of relativistic corrections ir the energy losses of electrons during the inverse Compton scattering. A comparison with the existing experimental data is carried out

Spread spectrum image data hiding in the encrypted discrete cosine transform coefficients

Science.gov (United States)

Zhang, Xiaoqiang; Wang, Z. Jane

2013-10-01

Digital watermarking and data hiding are important tools for digital rights protection of media data. Spread spectrum (SS)-based watermarking and data-hiding approaches are popular due to their outstanding robustness, but their security might not be sufficient. To improve the security of SS, a SS-based image data-hiding approach is proposed by encrypting the discrete cosine transform coefficients of the host image with the piecewise linear chaotic map, before the operation of watermark embedding. To evaluate the performance of the proposed approach, simulations and analyses of its robustness and security are carried out. The average bit-error-rate values on 100 real images from the Berkeley segmentation dataset under the JPEG compression, additive Gaussian noise, salt and pepper noise, and cropping attacks are reported. Experimental results show that the proposed approach can maintain the high robustness of traditional SS schemes and, meanwhile, also improve the security. The proposed approach can extend the key space of traditional SS schemes from 10 to 10 and thus can resist brute-force attack and unauthorized detection watermark attack.

Discrete density of states

Energy Technology Data Exchange (ETDEWEB)

Aydin, Alhun; Sisman, Altug, E-mail: sismanal@itu.edu.tr

2016-03-22

By considering the quantum-mechanically minimum allowable energy interval, we exactly count number of states (NOS) and introduce discrete density of states (DOS) concept for a particle in a box for various dimensions. Expressions for bounded and unbounded continua are analytically recovered from discrete ones. Even though substantial fluctuations prevail in discrete DOS, they're almost completely flattened out after summation or integration operation. It's seen that relative errors of analytical expressions of bounded/unbounded continua rapidly decrease for high NOS values (weak confinement or high energy conditions), while the proposed analytical expressions based on Weyl's conjecture always preserve their lower error characteristic. - Highlights: • Discrete density of states considering minimum energy difference is proposed. • Analytical DOS and NOS formulas based on Weyl conjecture are given. • Discrete DOS and NOS functions are examined for various dimensions. • Relative errors of analytical formulas are much better than the conventional ones.

Model Predictive Control of a Wave Energy Converter with Discrete Fluid Power Power Take-Off System

Directory of Open Access Journals (Sweden)

Anders Hedegaard Hansen

2018-03-01

Full Text Available Wave power extraction algorithms for wave energy converters are normally designed without taking system losses into account leading to suboptimal power extraction. In the current work, a model predictive power extraction algorithm is designed for a discretized power take of system. It is shown how the quantized nature of a discrete fluid power system may be included in a new model predictive control algorithm leading to a significant increase in the harvested power. A detailed investigation of the influence of the prediction horizon and the time step is reported. Furthermore, it is shown how the inclusion of a loss model may increase the energy output. Based on the presented results it is concluded that power extraction algorithms based on model predictive control principles are both feasible and favorable for use in a discrete fluid power power take-off system for point absorber wave energy converters.

Molecular spectrum of laterally coupled quantum rings under intense terahertz radiation.

Science.gov (United States)

Baghramyan, Henrikh M; Barseghyan, Manuk G; Laroze, David

2017-09-05

We study the influence of intense THz laser radiation and electric field on molecular states of laterally coupled quantum rings. Laser radiation shows the capability to dissociate quantum ring molecule and add 2-fold degeneracy to the molecular states at the fixed value of the overlapping size between rings. It is shown that coupled to decoupled molecular states phase transition points form almost a straight line with a slope equal to two. In addition, the electric field direction dependent energy spectrum shows unexpected oscillations, demonstrating strong coupling between molecular states. Besides, intraband absorption is considered, showing both blue and redshifts in its spectrum. The obtained results can be useful for the controlling of degeneracy of the discrete energy spectrum of nanoscale structures and in the tunneling effects therein.

Exact wave packet decoherence dynamics in a discrete spectrum environment

International Nuclear Information System (INIS)

Tu, Matisse W Y; Zhang Weimin

2008-01-01

We find an exact analytical solution of the reduced density matrix from the Feynman-Vernon influence functional theory for a wave packet in an environment containing a few discrete modes. We obtain two intrinsic energy scales relating to the time scales of the system and the environment. The different relationship between these two scales alters the overall form of the solution of the system. We also introduce a decoherence measure for a single wave packet which is defined as the ratio of Schroedinger uncertainty over the delocalization extension of the wave packet and characterizes the time-evolution behaviour of the off-diagonal reduced density matrix element. We utilize the exact solution and the decoherence measure to study the wave packet decoherence dynamics. We further demonstrate how the dynamical diffusion of the wave packet leads to non-Markovian decoherence in such a microscopic environment.

Multislot Simultaneous Spectrum Sensing and Energy Harvesting in Cognitive Radio

Directory of Open Access Journals (Sweden)

Xin Liu

2016-07-01

Full Text Available In cognitive radio (CR, the spectrum sensing of the primary user (PU may consume some electrical power from the battery capacity of the secondary user (SU, resulting in a decrease in the transmission power of the SU. In this paper, a multislot simultaneous spectrum sensing and energy harvesting model is proposed, which uses the harvested radio frequency (RF energy of the PU signal to supply the spectrum sensing. In the proposed model, the sensing duration is divided into multiple sensing slots consisting of one local-sensing subslot and one energy-harvesting subslot. If the PU is detected to be present in the local-sensing subslot, the SU will harvest RF energy of the PU signal in the energy-harvesting slot, otherwise, the SU will continue spectrum sensing. The global decision on the presence of the PU is obtained through combining local sensing results from all the sensing slots by adopting “Or-logic Rule”. A joint optimization problem of sensing time and time splitter factor is proposed to maximize the throughput of the SU under the constraints of probabilities of false alarm and detection and energy harvesting. The simulation results have shown that the proposed model can clearly improve the maximal throughput of the SU compared to the traditional sensing-throughput tradeoff model.

Discrete Exterior Calculus Discretization of Incompressible Navier-Stokes Equations

KAUST Repository

Mohamed, Mamdouh S.

2017-05-23

A conservative discretization of incompressible Navier-Stokes equations over surface simplicial meshes is developed using discrete exterior calculus (DEC). Numerical experiments for flows over surfaces reveal a second order accuracy for the developed scheme when using structured-triangular meshes, and first order accuracy otherwise. The mimetic character of many of the DEC operators provides exact conservation of both mass and vorticity, in addition to superior kinetic energy conservation. The employment of barycentric Hodge star allows the discretization to admit arbitrary simplicial meshes. The discretization scheme is presented along with various numerical test cases demonstrating its main characteristics.

Energy efficient cross layer design for spectrum sharing systems

KAUST Repository

Alabbasi, AbdulRahman; Shihada, Basem

2016-01-01

We propose a cross layer design that optimizes the energy efficiency of spectrum sharing systems. The energy per good bit (EPG) is considered as an energy efficiency metric. We optimize the secondary user's transmission power and media access frame

A discrete-continuous choice model of climate change impacts on energy

International Nuclear Information System (INIS)

Morrison, W.N.; Mendelsohn, R.

1998-01-01

This paper estimates a discrete-continuous fuel choice model in order to explore climate impacts on the energy sector. The model is estimated on a national data set of firms and households. The results reveal that actors switch from oil in cold climates to electricity and natural gas in warm climates and that fuel-specific expenditures follow a U-shaped relationship with respect to temperature. The model implies that warming will increase American energy expenditures, reflecting a sizable welfare damage

A new class of galactic discrete gamma ray sources: Chaotic winds of massive stars

Science.gov (United States)

Chen, Wan; White, Richard L.

1992-01-01

We propose a new class of galactic discrete gamma-ray sources, the chaotic, high mass-loss-rate winds from luminous early-type stars. Early-type stellar winds are highly unstable due to intrinsic line-driven instabilities, and so are permeated by numerous strong shocks. These shocks can accelerate a small fraction of thermal electrons and ions to relativistic energies via the first-order Fermi mechanism. A power-law-like photon spectrum extending from keV to above 10 MeV energies is produced by inverse Compton scattering of the extremely abundant stellar UV photons by the relativistic electrons. In addition, a typical pi(sup 0)-decay gamma-ray spectrum is generated by proton-ion interactions in the densest part of the winds.

Reflectionless discrete Schr\\"odinger operators are spectrally atypical

OpenAIRE

VandenBoom, Tom

2017-01-01

We prove that, if an isospectral torus contains a discrete Schr\\"odinger operator with nonconstant potential, the shift dynamics on that torus cannot be minimal. Consequently, we specify a generic sense in which finite unions of nondegenerate closed intervals having capacity one are not the spectrum of any reflectionless discrete Schr\\"odinger operator. We also show that the only reflectionless discrete Schr\\"odinger operators having zero, one, or two spectral gaps are periodic.

Discrete Displacement Hydraulic Power Take-Off System for the Wavestar Wave Energy Converter

Directory of Open Access Journals (Sweden)

Enrique Vidal

2013-08-01

Full Text Available The Wavestar Wave Energy Converter (WEC is a multiple absorber concept, consisting of 20 hemisphere shaped floats attached to a single platform. The heart of the Wavestar WEC is the Power Take-Off (PTO system, converting the wave induced motion of the floats into a steady power output to the grid. In the present work, a PTO based on a novel discrete displacement fluid power technology is explored for the Wavestar WEC. Absorption of power from the floats is performed by hydraulic cylinders, supplying power to a common fixed pressure system with accumulators for energy smoothing. The stored pressure energy is converted into electricity at a steady pace by hydraulic motors and generators. The storage, thereby, decouples the complicated process of wave power absorption from power generation. The core for enabling this PTO technology is implementing a near loss-free force control of the energy absorbing cylinders. This is achieved by using special multi-chambered cylinders, where the different chambers may be connected to the available system pressures using fast on/off valves. Resultantly, a Discrete Displacement Cylinder (DDC is created, allowing near loss free discrete force control. This paper presents a complete PTO system for a 20 float Wavestar based on the DDC. The WEC and PTO is rigorously modeled from incident waves to the electric output to the grid. The resulting model of +600 states is simulated in different irregular seas, showing that power conversion efficiencies above 70% from input power to electrical power is achievable for all relevant sea conditions.

Adaptive, full-spectrum solar energy system

Science.gov (United States)

Muhs, Jeffrey D.; Earl, Dennis D.

2003-08-05

An adaptive full spectrum solar energy system having at least one hybrid solar concentrator, at least one hybrid luminaire, at least one hybrid photobioreactor, and a light distribution system operably connected to each hybrid solar concentrator, each hybrid luminaire, and each hybrid photobioreactor. A lighting control system operates each component.

Energy Cost of Avoiding Pressure Oscillations in a Discrete Fluid Power Force System

DEFF Research Database (Denmark)

Hansen, Anders Hedegaard; Pedersen, Henrik Clemmensen

2015-01-01

In secondary valve controlled discrete fluid power force systems the valve opening trajectory greatly influences the pressure dynamics in the actuator chambers. For discrete fluid power systems featuring hoses of significant length pressure oscillations due to fast valve switching is well......-known. This paper builds upon theoretical findings on how shaping of the valve opening may reduce the cylinder pressure oscillations. The current paper extents the work by implementing the valve opening characteristics reducing the pressure oscillations on a full scale power take-off test-bench for wave energy...... will present measurements comparing pressure dynamics for two valve opening algorithms. In addition the paper will give a theoretical investigation of the energy loss during valve shifting and finally measurements of average power output from the power take-off system in various sea states are compared...

Energy detection for spectrum sensing in cognitive radio

CERN Document Server

Atapattu, Saman; Jiang, Hai

2014-01-01

This Springer Brief focuses on the current state-of-the-art research on spectrum sensing by using energy detection, a low-complexity and low-cost technique. It includes a comprehensive summary of recent research, fundamental theories, possible architectures, useful performance measurements of energy detection and applications of energy detection. Concise, practical chapters explore conventional energy detectors, alternative forms of energy detectors, performance measurements, diversity techniques and cooperative networks. The careful analysis enables reader to identify the most efficient techn

A low noise discrete velocity method for the Boltzmann equation with quantized rotational and vibrational energy

Science.gov (United States)

Clarke, Peter; Varghese, Philip; Goldstein, David

2018-01-01

A discrete velocity method is developed for gas mixtures of diatomic molecules with both rotational and vibrational energy states. A full quantized model is described, and rotation-translation and vibration-translation energy exchanges are simulated using a Larsen-Borgnakke exchange model. Elastic and inelastic molecular interactions are modeled during every simulated collision to help produce smooth internal energy distributions. The method is verified by comparing simulations of homogeneous relaxation by our discrete velocity method to numerical solutions of the Jeans and Landau-Teller equations, and to direct simulation Monte Carlo. We compute the structure of a 1D shock using this method, and determine how the rotational energy distribution varies with spatial location in the shock and with position in velocity space.

Electron energy spectrum and maximum disruption angle under multi-photon beamstrahlung

Energy Technology Data Exchange (ETDEWEB)

Yokoya, Kaoru; Chen, Pisin

1989-03-01

The final electron energy spectrum under multi-photon beamstrahlung process is derived analytically in the classical and the intermediate regimes. The maximum disruption angle from the low energy tail of the spectrum is also estimated. The results are then applied to the TLC and the CLIC parameters. 6 refs., 1 fig., 1 tab.

Discrete kinetic models from funneled energy landscape simulations.

Directory of Open Access Journals (Sweden)

Nicholas P Schafer

Full Text Available A general method for facilitating the interpretation of computer simulations of protein folding with minimally frustrated energy landscapes is detailed and applied to a designed ankyrin repeat protein (4ANK. In the method, groups of residues are assigned to foldons and these foldons are used to map the conformational space of the protein onto a set of discrete macrobasins. The free energies of the individual macrobasins are then calculated, informing practical kinetic analysis. Two simple assumptions about the universality of the rate for downhill transitions between macrobasins and the natural local connectivity between macrobasins lead to a scheme for predicting overall folding and unfolding rates, generating chevron plots under varying thermodynamic conditions, and inferring dominant kinetic folding pathways. To illustrate the approach, free energies of macrobasins were calculated from biased simulations of a non-additive structure-based model using two structurally motivated foldon definitions at the full and half ankyrin repeat resolutions. The calculated chevrons have features consistent with those measured in stopped flow chemical denaturation experiments. The dominant inferred folding pathway has an "inside-out", nucleation-propagation like character.

Operator algebras for general one-dimensional quantum mechanical potentials with discrete spectrum

International Nuclear Information System (INIS)

Wuensche, Alfred

2002-01-01

We define general lowering and raising operators of the eigenstates for one-dimensional quantum mechanical potential problems leading to discrete energy spectra and investigate their associative algebra. The Hamilton operator is quadratic in these lowering and raising operators and corresponding representations of operators for action and angle are found. The normally ordered representation of general operators using combinatorial elements such as partitions is derived. The introduction of generalized coherent states is discussed. Linear laws for the spacing of the energy eigenvalues lead to the Heisenberg-Weyl group and general quadratic laws of level spacing to unitary irreducible representations of the Lie group SU(1, 1) that is considered in detail together with a limiting transition from this group to the Heisenberg-Weyl group. The relation of the approach to quantum deformations is discussed. In two appendices, the classical and quantum mechanical treatment of the squared tangent potential is presented as a special case of a system with quadratic level spacing

Discrete gauge symmetries in discrete MSSM-like orientifolds

International Nuclear Information System (INIS)

Ibáñez, L.E.; Schellekens, A.N.; Uranga, A.M.

2012-01-01

Motivated by the necessity of discrete Z N symmetries in the MSSM to insure baryon stability, we study the origin of discrete gauge symmetries from open string sector U(1)'s in orientifolds based on rational conformal field theory. By means of an explicit construction, we find an integral basis for the couplings of axions and U(1) factors for all simple current MIPFs and orientifolds of all 168 Gepner models, a total of 32 990 distinct cases. We discuss how the presence of discrete symmetries surviving as a subgroup of broken U(1)'s can be derived using this basis. We apply this procedure to models with MSSM chiral spectrum, concretely to all known U(3)×U(2)×U(1)×U(1) and U(3)×Sp(2)×U(1)×U(1) configurations with chiral bi-fundamentals, but no chiral tensors, as well as some SU(5) GUT models. We find examples of models with Z 2 (R-parity) and Z 3 symmetries that forbid certain B and/or L violating MSSM couplings. Their presence is however relatively rare, at the level of a few percent of all cases.

Research on influence of energy spectrum response of ICT detector arrays

International Nuclear Information System (INIS)

Zhou Rifeng; Gao Fuqiang; Zhang Ping

2008-01-01

The energy spectrum response is important characteristic for X-ray ICT detector. But there exist many difficulties to measure these parameters by experiments. The energy spectrum response of CdWO 4 detector was simulated by using the EGSnrc code. Meanwhile the effect of detection efficiency was analyzed by the distribution of accelerator bremsstrahlung spectra and the X-ray spectrum hardening, and some theoretic parameters were offered for the consistent and no-linearity correction of detector arrays. It was applied to ICT image correction, and a satisfying result was obtained. (authors)

Energy and spectrum efficiency in rural areas based on cognitive radio technology

CSIR Research Space (South Africa)

Masonta, MT

2009-09-01

Full Text Available spectrum scarcity in the most energy efficient manner. In this paper, researchers present the proposed work to be carried out as part of a doctoral thesis to address the spectrum scarcity and transmission power in energy constrained rural areas....

A numerical method for the quasi-incompressible Cahn–Hilliard–Navier–Stokes equations for variable density flows with a discrete energy law

International Nuclear Information System (INIS)

Guo, Z.; Lin, P.; Lowengrub, J.S.

2014-01-01

In this paper, we investigate numerically a diffuse interface model for the Navier–Stokes equation with fluid–fluid interface when the fluids have different densities [48]. Under minor reformulation of the system, we show that there is a continuous energy law underlying the system, assuming that all variables have reasonable regularities. It is shown in the literature that an energy law preserving method will perform better for multiphase problems. Thus for the reformulated system, we design a C 0 finite element method and a special temporal scheme where the energy law is preserved at the discrete level. Such a discrete energy law (almost the same as the continuous energy law) for this variable density two-phase flow model has never been established before with C 0 finite element. A Newton method is introduced to linearise the highly non-linear system of our discretization scheme. Some numerical experiments are carried out using the adaptive mesh to investigate the scenario of coalescing and rising drops with differing density ratio. The snapshots for the evolution of the interface together with the adaptive mesh at different times are presented to show that the evolution, including the break-up/pinch-off of the drop, can be handled smoothly by our numerical scheme. The discrete energy functional for the system is examined to show that the energy law at the discrete level is preserved by our scheme

Possibilities of the observation of the discrete spectrum of the water dimer at equilibrium in millimeter-wave band

International Nuclear Information System (INIS)

Krupnov, A.F.; Tretyakov, M.Yu.; Leforestier, C.

2009-01-01

Attempts of experimental observations of the water dimer spectrum at equilibrium conditions have lasted for more than 40 years since the dimeric hypothesis for extra absorption, but have not yielded any positive confirmed result. In the present paper a new approach is considered: using a high-resolution millimeter-wave spectrum of the water dimer at equilibrium, calculated by a rigorous fully quantum method, we show the potential existence of discernible spectral series of discrete features of the water dimer, which correspond to J+1 1 symmetry, already observed in cold molecular beam experiments and having, therefore, well-defined positions. The intensity of spectral series and contrast to the remaining continuum-like spectrum of the dimer are calculated and compared with the monomer absorption. The suitability of two types of microwave spectrometers for observing these series is considered. The collisional line-width of millimeter lines of the dimer at equilibrium is estimated and the width of IR dimer bands is discussed. It is pointed out that the large width of IR dimer bands may pose difficulties for their reliable observation and conclusive separation from the rest of absorption in water vapor. This situation contrasts with the suggested approach of dimer detection in millimeter-waves.

Discrete dynamics versus analytic dynamics

DEFF Research Database (Denmark)

Toxværd, Søren

2014-01-01

For discrete classical Molecular dynamics obtained by the “Verlet” algorithm (VA) with the time increment h there exists a shadow Hamiltonian H˜ with energy E˜(h) , for which the discrete particle positions lie on the analytic trajectories for H˜ . Here, we proof that there, independent...... of such an analytic analogy, exists an exact hidden energy invariance E * for VA dynamics. The fact that the discrete VA dynamics has the same invariances as Newtonian dynamics raises the question, which of the formulations that are correct, or alternatively, the most appropriate formulation of classical dynamics....... In this context the relation between the discrete VA dynamics and the (general) discrete dynamics investigated by Lee [Phys. Lett. B122, 217 (1983)] is presented and discussed....

Functions with disconnected spectrum sampling, interpolation, translates

CERN Document Server

Olevskii, Alexander M

2016-01-01

The classical sampling problem is to reconstruct entire functions with given spectrum S from their values on a discrete set L. From the geometric point of view, the possibility of such reconstruction is equivalent to determining for which sets L the exponential system with frequencies in L forms a frame in the space L^2(S). The book also treats the problem of interpolation of discrete functions by analytic ones with spectrum in S and the problem of completeness of discrete translates. The size and arithmetic structure of both the spectrum S and the discrete set L play a crucial role in these problems. After an elementary introduction, the authors give a new presentation of classical results due to Beurling, Kahane, and Landau. The main part of the book focuses on recent progress in the area, such as construction of universal sampling sets, high-dimensional and non-analytic phenomena. The reader will see how methods of harmonic and complex analysis interplay with various important concepts in different areas, ...

Quotients of irreducible N=2 superconformal coset theories by discrete symmetries

International Nuclear Information System (INIS)

Bailin, D.; Love, A.

1990-01-01

The spectrum of massless states is studied for the irreducible N=2 superconformal coset theories when these theories are quotiented by discrete symmetries, including the effect of embedding the discrete symmetries in the gauge group. (orig.)

Energy spectrum of tearing mode turbulence in sheared background field

Science.gov (United States)

Hu, Di; Bhattacharjee, Amitava; Huang, Yi-Min

2018-06-01

The energy spectrum of tearing mode turbulence in a sheared background magnetic field is studied in this work. We consider the scenario where the nonlinear interaction of overlapping large-scale modes excites a broad spectrum of small-scale modes, generating tearing mode turbulence. The spectrum of such turbulence is of interest since it is relevant to the small-scale back-reaction on the large-scale field. The turbulence we discuss here differs from traditional MHD turbulence mainly in two aspects. One is the existence of many linearly stable small-scale modes which cause an effective damping during the energy cascade. The other is the scale-independent anisotropy induced by the large-scale modes tilting the sheared background field, as opposed to the scale-dependent anisotropy frequently encountered in traditional critically balanced turbulence theories. Due to these two differences, the energy spectrum deviates from a simple power law and takes the form of a power law multiplied by an exponential falloff. Numerical simulations are carried out using visco-resistive MHD equations to verify our theoretical predictions, and a reasonable agreement is found between the numerical results and our model.

Observations of discrete energy loss effects in spectra of positrons reflected from solid surfaces

International Nuclear Information System (INIS)

Dale, J.M.; Hulett, L.D.; Pendyala, S.

1980-01-01

Surfaces of tungsten and silicon have been bombarded with monoenergetic beams of positrons and electrons. Spectra of reflected particles show energy loss tails with discrete peaks at kinetic energies about 15 eV lower than that of the elastic peaks. In the higher energy loss range for tungsten, positron spectra show fine structure that is not apparent in the electron spectra. This suggests that the positrons are losing energy through mechanisms different from that of the electrons

A method for measuring the energy spectrum of coincidence events in positron emission tomography.

Science.gov (United States)

Goertzen, Andrew L; Stout, David B; Thompson, Christopher J

2010-01-21

Positron emission tomography (PET) system energy response is typically characterized in singles detection mode, yet there are situations in which the energy spectrum of coincidence events might be different than the spectrum measured in singles mode. Examples include imaging with isotopes that emit a prompt gamma in coincidence with a positron emission, imaging with low activity in a LSO/LYSO-based cameras, in which the intrinsic activity is significant, and in high scatter situations where the two 511 keV photons have different scattering probabilities (i.e. off-center line source). The ability to accurately measure the energy spectrum of coincidence events could be used for validating simulation models, optimizing energy discriminator levels and examining scatter models and corrections. For many PET systems operating in coincidence mode, the only method available for estimating the energy spectrum is to step the lower and upper level discriminators (LLD and ULD). Simple measurement techniques such as using a narrow sliding energy window or stepping only the LLD will not yield a spectrum of coincidence events that is accurate for cases where there are different energy components contributing to the spectrum. In this work we propose a new method of measuring the energy spectrum of coincidence events in PET based on a linear combination of two sets of coincident count measurements: one made by stepping the LLD and one made by stepping the ULD. The method was tested using both Monte Carlo simulations of a Siemens microPET R4 camera and measured data acquired on a Siemens Inveon PET camera. The results show that our energy spectrum calculation method accurately measures the coincident energy spectra for cases including the beta/gamma spectrum of the (176)Lu intrinsic activity present in the LSO scintillator crystals, a (68)Ge source and an (124)I source (in which there are prompt gamma-rays emitted together with the positron).

Reflectionless Discrete Schrödinger Operators are Spectrally Atypical

Science.gov (United States)

VandenBoom, Tom

2017-12-01

We prove that, if an isospectral torus contains a discrete Schrödinger operator with nonconstant potential, the shift dynamics on that torus cannot be minimal. Consequently, we specify a generic sense in which finite unions of nondegenerate closed intervals having capacity one are not the spectrum of any reflectionless discrete Schrödinger operator. We also show that the only reflectionless discrete Schrödinger operators having zero, one, or two spectral gaps are periodic.

Gamma ray energy spectrum of a buried radioactive source

Energy Technology Data Exchange (ETDEWEB)

Massey, N B

1957-07-01

Because of current attempts to utilize airborne gamma-ray scintillation spectrometers as a means of detecting and identifying buried radioactive mineral deposits, it has become important to study the effects of multiple scattering on the gamma-ray energy spectrum of a source buried in a semi-infinite medium. A series of ten experiments was made. First a scintillation detector was located in air at a fixed distance above a 250 microcurie cobalt-60 source suspended in a large tank. The level of water was raised from 25 cm below the source to 50 cm above, and the gamma-ray energy spectrum was observed. It was found that the high energy portion of the cobalt-60 spectrum remained identifiable even when the source was submerged more than five half-lengths. Further, the ratio of the counting rate of the total incident gamma radiation to the counting rate of the primary 1.33 MeV radiation was found to be very nearly linearly proportional to the depth of water cover. This leads to an empirical method for determining the depth of burial of a cobalt-60 point source. (author)

Measurement of the ν _{μ } energy spectrum with IceCube-79

Science.gov (United States)

Aartsen, M. G.; Ackermann, M.; Adams, J.; Aguilar, J. A.; Ahlers, M.; Ahrens, M.; Al Samarai, I.; Altmann, D.; Andeen, K.; Anderson, T.; Ansseau, I.; Anton, G.; Archinger, M.; Argüelles, C.; Auffenberg, J.; Axani, S.; Bagherpour, H.; Bai, X.; Barwick, S. W.; Baum, V.; Bay, R.; Beatty, J. J.; Becker Tjus, J.; Becker, K.-H.; BenZvi, S.; Berley, D.; Bernardini, E.; Besson, D. Z.; Binder, G.; Bindig, D.; Blaufuss, E.; Blot, S.; Bohm, C.; Börner, M.; Bos, F.; Bose, D.; Böser, S.; Botner, O.; Bradascio, F.; Braun, J.; Brayeur, L.; Bretz, H.-P.; Bron, S.; Burgman, A.; Carver, T.; Casier, M.; Cheung, E.; Chirkin, D.; Christov, A.; Clark, K.; Classen, L.; Coenders, S.; Collin, G. H.; Conrad, J. M.; Cowen, D. F.; Cross, R.; Day, M.; de André, J. P. A. M.; De Clercq, C.; del Pino Rosendo, E.; Dembinski, H.; De Ridder, S.; Desiati, P.; de Vries, K. D.; de Wasseige, G.; de With, M.; DeYoung, T.; Díaz-Vélez, J. C.; di Lorenzo, V.; Dujmovic, H.; Dumm, J. P.; Dunkman, M.; Eberhardt, B.; Ehrhardt, T.; Eichmann, B.; Eller, P.; Euler, S.; Evenson, P. A.; Fahey, S.; Fazely, A. R.; Feintzeig, J.; Felde, J.; Filimonov, K.; Finley, C.; Flis, S.; Fösig, C.-C.; Franckowiak, A.; Friedman, E.; Fuchs, T.; Gaisser, T. K.; Gallagher, J.; Gerhardt, L.; Ghorbani, K.; Giang, W.; Gladstone, L.; Glauch, T.; Glüsenkamp, T.; Goldschmidt, A.; Gonzalez, J. G.; Grant, D.; Griffith, Z.; Haack, C.; Hallgren, A.; Halzen, F.; Hansen, E.; Hansmann, T.; Hanson, K.; Hebecker, D.; Heereman, D.; Helbing, K.; Hellauer, R.; Hickford, S.; Hignight, J.; Hill, G. C.; Hoffman, K. D.; Hoffmann, R.; Hoshina, K.; Huang, F.; Huber, M.; Hultqvist, K.; In, S.; Ishihara, A.; Jacobi, E.; Japaridze, G. S.; Jeong, M.; Jero, K.; Jones, B. J. P.; Kang, W.; Kappes, A.; Karg, T.; Karle, A.; Katz, U.; Kauer, M.; Keivani, A.; Kelley, J. L.; Kheirandish, A.; Kim, J.; Kim, M.; Kintscher, T.; Kiryluk, J.; Kittler, T.; Klein, S. R.; Kohnen, G.; Koirala, R.; Kolanoski, H.; Konietz, R.; Köpke, L.; Kopper, C.; Kopper, S.; Koskinen, D. J.; Kowalski, M.; Krings, K.; Kroll, M.; Krückl, G.; Krüger, C.; Kunnen, J.; Kunwar, S.; Kurahashi, N.; Kuwabara, T.; Kyriacou, A.; Labare, M.; Lanfranchi, J. L.; Larson, M. J.; Lauber, F.; Lennarz, D.; Lesiak-Bzdak, M.; Leuermann, M.; Lu, L.; Lünemann, J.; Madsen, J.; Maggi, G.; Mahn, K. B. M.; Mancina, S.; Maruyama, R.; Mase, K.; Maunu, R.; McNally, F.; Meagher, K.; Medici, M.; Meier, M.; Menne, T.; Merino, G.; Meures, T.; Miarecki, S.; Micallef, J.; Momenté, G.; Montaruli, T.; Moulai, M.; Nahnhauer, R.; Naumann, U.; Neer, G.; Niederhausen, H.; Nowicki, S. C.; Nygren, D. R.; Obertacke Pollmann, A.; Olivas, A.; O'Murchadha, A.; Palczewski, T.; Pandya, H.; Pankova, D. V.; Peiffer, P.; Penek, Ö.; Pepper, J. A.; Pérez de los Heros, C.; Pieloth, D.; Pinat, E.; Price, P. B.; Przybylski, G. T.; Quinnan, M.; Raab, C.; Rädel, L.; Rameez, M.; Rawlins, K.; Reimann, R.; Relethford, B.; Relich, M.; Resconi, E.; Rhode, W.; Richman, M.; Riedel, B.; Robertson, S.; Rongen, M.; Rott, C.; Ruhe, T.; Ryckbosch, D.; Rysewyk, D.; Sabbatini, L.; Sanchez Herrera, S. E.; Sandrock, A.; Sandroos, J.; Sarkar, S.; Satalecka, K.; Schlunder, P.; Schmidt, T.; Schoenen, S.; Schöneberg, S.; Schumacher, L.; Seckel, D.; Seunarine, S.; Soldin, D.; Song, M.; Spiczak, G. M.; Spiering, C.; Stachurska, J.; Stanev, T.; Stasik, A.; Stettner, J.; Steuer, A.; Stezelberger, T.; Stokstad, R. G.; Stößl, A.; Ström, R.; Strotjohann, N. L.; Sullivan, G. W.; Sutherland, M.; Taavola, H.; Taboada, I.; Tatar, J.; Tenholt, F.; Ter-Antonyan, S.; Terliuk, A.; Tešić, G.; Tilav, S.; Toale, P. A.; Tobin, M. N.; Toscano, S.; Tosi, D.; Tselengidou, M.; Tung, C. F.; Turcati, A.; Unger, E.; Usner, M.; Vandenbroucke, J.; van Eijndhoven, N.; Vanheule, S.; van Rossem, M.; van Santen, J.; Vehring, M.; Voge, M.; Vogel, E.; Vraeghe, M.; Walck, C.; Wallace, A.; Wallraff, M.; Wandkowsky, N.; Waza, A.; Weaver, Ch.; Weiss, M. J.; Wendt, C.; Westerhoff, S.; Whelan, B. J.; Wickmann, S.; Wiebe, K.; Wiebusch, C. H.; Wille, L.; Williams, D. R.; Wills, L.; Wolf, M.; Wood, T. R.; Woolsey, E.; Woschnagg, K.; Xu, D. L.; Xu, X. W.; Xu, Y.; Yanez, J. P.; Yodh, G.; Yoshida, S.; Zoll, M.

2017-10-01

IceCube is a neutrino observatory deployed in the glacial ice at the geographic South Pole. The ν _μ energy unfolding described in this paper is based on data taken with IceCube in its 79-string configuration. A sample of muon neutrino charged-current interactions with a purity of 99.5% was selected by means of a multivariate classification process based on machine learning. The subsequent unfolding was performed using the software Truee. The resulting spectrum covers an E_ν -range of more than four orders of magnitude from 125 GeV to 3.2 PeV. Compared to the Honda atmospheric neutrino flux model, the energy spectrum shows an excess of more than 1.9 σ in four adjacent bins for neutrino energies E_ν ≥ 177.8 {TeV}. The obtained spectrum is fully compatible with previous measurements of the atmospheric neutrino flux and recent IceCube measurements of a flux of high-energy astrophysical neutrinos.

Measurement of the νμ energy spectrum with IceCube-79

International Nuclear Information System (INIS)

Aartsen, M.G.; Hill, G.C.; Kyriacou, A.; Robertson, S.; Wallace, A.; Whelan, B.J.; Ackermann, M.; Bernardini, E.; Blot, S.; Bradascio, F.; Bretz, H.P.; Franckowiak, A.; Jacobi, E.; Karg, T.; Kintscher, T.; Kunwar, S.; Nahnhauer, R.; Satalecka, K.; Spiering, C.; Stachurska, J.; Stasik, A.; Strotjohann, N.L.; Terliuk, A.; Usner, M.; Santen, J. van; Adams, J.; Bagherpour, H.; Aguilar, J.A.; Ansseau, I.; Heereman, D.; Meagher, K.; Meures, T.; O'Murchadha, A.; Pinat, E.; Raab, C.; Ahlers, M.; Braun, J.; Chirkin, D.; Day, M.; Desiati, P.; Diaz-Velez, J.C.; Fahey, S.; Feintzeig, J.; Ghorbani, K.; Gladstone, L.; Griffith, Z.; Halzen, F.; Hanson, K.; Hoshina, K.; Jero, K.; Karle, A.; Kauer, M.; Kelley, J.L.; Kheirandish, A.; Krueger, C.; Mancina, S.; McNally, F.; Merino, G.; Sabbatini, L.; Tobin, M.N.; Tosi, D.; Vandenbroucke, J.; Van Rossem, M.; Wandkowsky, N.; Wendt, C.; Westerhoff, S.; Wille, L.; Xu, D.L.; Ahrens, M.; Bohm, C.; Dumm, J.P.; Finley, C.; Flis, S.; Hultqvist, K.; Walck, C.; Wolf, M.; Zoll, M.; Al Samarai, I.; Bron, S.; Carver, T.; Christov, A.; Montaruli, T.; Altmann, D.; Anton, G.; Gluesenkamp, T.; Katz, U.; Kittler, T.; Tselengidou, M.; Andeen, K.; Anderson, T.; Dunkman, M.; Eller, P.; Huang, F.; Keivani, A.; Lanfranchi, J.L.; Pankova, D.V.; Quinnan, M.; Tesic, G.; Weiss, M.J.; Archinger, M.; Baum, V.; Boeser, S.; Del Pino Rosendo, E.; Di Lorenzo, V.; Eberhardt, B.; Ehrhardt, T.; Foesig, C.C.; Koepke, L.; Krueckl, G.; Momente, G.; Peiffer, P.; Sandroos, J.; Steuer, A.; Wiebe, K.; Argueelles, C.; Axani, S.; Collin, G.H.; Conrad, J.M.; Jones, B.J.P.; Moulai, M.; Auffenberg, J.; Glauch, T.; Haack, C.; Hansmann, T.; Konietz, R.; Leuermann, M.; Penek, Oe.; Raedel, L.; Reimann, R.; Rongen, M.; Schoenen, S.; Schumacher, L.; Stettner, J.; Vehring, M.; Vogel, E.; Wallraff, M.; Waza, A.; Wickmann, S.; Wiebusch, C.H.; Bai, X.; Barwick, S.W.; Yodh, G.; Bay, R.; Filimonov, K.; Price, P.B.; Woschnagg, K.; Beatty, J.J.; Becker Tjus, J.; Bos, F.; Eichmann, B.; Kroll, M.; Schoeneberg, S.; Tenholt, F.; Becker, K.H.; Bindig, D.; Helbing, K.; Hickford, S.; Hoffmann, R.; Kopper, S.; Lauber, F.; Naumann, U.; Obertacke Pollmann, A.; Soldin, D.; BenZvi, S.; Cross, R.; Berley, D.; Blaufuss, E.; Cheung, E.; Felde, J.; Friedman, E.; Hellauer, R.; Hoffman, K.D.; Maunu, R.; Olivas, A.; Schmidt, T.; Song, M.; Sullivan, G.W.; Besson, D.Z.; Binder, G.; Gerhardt, L.; Klein, S.R.; Miarecki, S.; Palczewski, T.; Tatar, J.; Boerner, M.; Fuchs, T.; Meier, M.; Menne, T.; Pieloth, D.; Rhode, W.; Ruhe, T.; Sandrock, A.; Schlunder, P.

2017-01-01

IceCube is a neutrino observatory deployed in the glacial ice at the geographic South Pole. The ν μ energy unfolding described in this paper is based on data taken with IceCube in its 79-string configuration. A sample of muon neutrino charged-current interactions with a purity of 99.5% was selected by means of a multivariate classification process based on machine learning. The subsequent unfolding was performed using the software Truee. The resulting spectrum covers an E ν -range of more than four orders of magnitude from 125 GeV to 3.2 PeV. Compared to the Honda atmospheric neutrino flux model, the energy spectrum shows an excess of more than 1.9σ in four adjacent bins for neutrino energies E ν ≥ 177.8 TeV. The obtained spectrum is fully compatible with previous measurements of the atmospheric neutrino flux and recent IceCube measurements of a flux of high-energy astrophysical neutrinos. (orig.)

Measurements of the energy spectrum of backscattered fast neutrons

International Nuclear Information System (INIS)

Segal, Y.

1976-03-01

Experimental measurements have been made of the energy spectra of neutrons transmitted through slabs of iron, lead and perspex for incident neutron energies of 0.5, 1.0, 1.5 and 1.8 MeV. The neutron energy measurements were made using a He-3 spectrometer. The dependence of the neutrons energy spectrum as a function of scattering thickness was determined. The neutrons source used was a 3MeV Van de Graaff accelerator with a tritium target using the H 3 (p,n) He 3 reaction. The results obtained by the investigator on energy dependence of transmitted neutrons as a function of thickness of scattering material were compared, where possible, with the results obtained by other workers. The comparisons indicated good agreement. The experiment's results are compared with MORSE Monte Carlo calculated values. It is worthwhile to note that direct comparison between measured cross section values and the recommended ones are very far from satisfactory. In almost all cases the calculated spectrum is harder than the experimental one, a situation common to the penetrating and the back-scattered flux

Generation and reception of spread-spectrum signals

Science.gov (United States)

Moser, R.

1983-05-01

The term 'spread-spectrum' implies a technique whereby digitized information is added to a pseudo-random number sequence and the resultant bit stream changes some parameter of the carrier frequency in discrete increments. The discrete modulation of the carrier frequency is usually realized either as a multiple level phase shift keyed or frequency shift keyed signal. The resultant PSK-modulated frequency spectrum is referred to as direct sequence spread-spectrum, whereas the FSK-modulated carrier frequency is referred to as a frequency hopped spread spectrum. These can be considered the major subsets of the more general term 'spread-spectrum'. In discussing signal reception, it is pointed out that active correlation methods are used for channel synchronization when the psuedo random sequences are long or when the processing gain is large, whereas the passive methods may be used for either short pseudo-random noise generation codes or to assist in attaining initial synchronization in long sequence spread-spectrum systems.

ADAPTIVE FULL-SPECTRUM SOLOR ENERGY SYSTEMS

Energy Technology Data Exchange (ETDEWEB)

Byard D. Wood

2004-04-01

This RD&D project is a three year team effort to develop a hybrid solar lighting (HSL) system that transports solar light from a paraboloidal dish concentrator to a luminaire via a large core polymer fiber optic. The luminaire can be a device to distribute sunlight into a space for the production of algae or it can be a device that is a combination of solar lighting and electric lighting. A benchmark prototype system has been developed to evaluate the HSL system. Sunlight is collected using a one-meter paraboloidal concentrator dish with two-axis tracking. A secondary mirror consisting of eight planar-segmented mirrors directs the visible part of the spectrum to eight fibers (receiver) and subsequently to eight luminaires. This results in about 8,200 lumens incident at each fiber tip. Each fiber can illuminate about 16.7 m{sup 2} (180 ft{sup 2}) of office space. The IR spectrum is directed to a thermophotovoltaic (TPV) array to produce electricity. During this reporting period, the project team made advancements in the design of the second generation (Alpha) system. For the Alpha system, the eight individual 12 mm fibers have been replaced with a centralized bundle of 3 mm fibers. The TRNSYS Full-Spectrum Solar Energy System model has been updated and new components have been added. The TPV array and nonimaging device have been tested and progress has been made in the fiber transmission models. A test plan was developed for both the high-lumen tests and the study to determine the non-energy benefits of daylighting. The photobioreactor team also made major advancements in the testing of model scale and bench top lab-scale systems.

Research on multi-spectrum detector in high-energy dual-energy X-ray imaging system

International Nuclear Information System (INIS)

Li Qinghua; Wang Xuewu; Li Jianmin; Kang Kejun; Li Yuanjing; Zhong Huaqiang

2008-01-01

The high-energy dual-energy X-ray imaging system can discriminate the material of the objects inspected, but when the objects are too thin, the discrimination becomes very difficult. This paper proposes the use of multi-spectrum detector to improve the ability to discriminate thin material, and a series of simulation were done with the Monte Carlo method. Firstly the X-ray depositions in the detectors with different thickness were calculated, and then the discrimination effects with different detector structure and parameters were calculated. The simulation results validated that using appropriate multi-spectrum detector can improve the discrimination accuracy of thin material, particularly thin high-Z material. (authors)

On the mass spectrum of particles

International Nuclear Information System (INIS)

Sajo, Istvan

1983-01-01

An eigenvalue formula of general validity was developed with correct mathematical methods from measured data of the stationary mass and self-energy of stationary particles; this is able to generate universally the mass of particles belonging to any class or group, i.e. to produce the spectra of particles with a stationary mass surpassing that of the electron. The author shows that this eigenvalue formula can be produced as the produc t of several partial formulae which, separately, are not more complicated than that developed by Balmer from data measured on the spectrum of the hydrogen atom. The validity of the first version of the formulae was checked for many particles discovered subsequently. The results are published in detail in the present paper, together with the method of development of the universal eigenvalue formula generating the mass spectrum of elementary particles. The formulae describing the discrete energy levels of the particles can be extended by considering the theory of special relativity, also to the mass of moving particles proportional with their inertia. (author)

Partial decay energy of 51Cr from inner bremsstrahlung spectrum

International Nuclear Information System (INIS)

Sanjeeviah, H.; Sanjeevaiah, B.

1980-01-01

The inner bremsstrahlung spectrum accompanying orbital electron capture decay of 51 Cr to the first excited state in 51 V was measured in coincidence with 320 keV gamma rays. From the Jauch plot of the spectrum the partial decay energy was deduced to be 433 +- 18 keV in good agreement with the previously measured value and the accepted mass difference. The overall shape factor of the inner bremsstrahlung spectrum was found to be a constant X(1.1 +- 0.1). (author)

Energy spectrum inverse problem of q -deformed harmonic oscillator and WBK approximation

International Nuclear Information System (INIS)

Sang, Nguyen Anh; Thuy, Do Thi Thu; Loan, Nguyen Thi Ha; Lan, Nguyen Tri; Viet, Nguyen Ai

2016-01-01

Using the connection between q-deformed harmonic oscillator and Morse-like anharmonic potential we investigate the energy spectrum inverse problem. Consider some energy levels of energy spectrum of q -deformed harmonic oscillator are known, we construct the corresponding Morse-like potential then find out the deform parameter q . The application possibility of using the WKB approximation in the energy spectrum inverse problem was discussed for the cases of parabolic potential (harmonic oscillator), Morse-like potential ( q -deformed harmonic oscillator). so we consider our deformed-three-levels simple model, where the set-parameters of Morse potential and the corresponding set-parameters of level deformations are easily and explicitly defined. For practical problems, we propose the deformed- three-levels simple model, where the set-parameters of Morse potential and the corresponding set-parameters of level deformations are easily and explicitly defined. (paper)

Effects of X-rays spectrum on the dose

International Nuclear Information System (INIS)

Rodriguez I, J. L.; Hernandez A, P. L.; Vega C, H. R.; Rivera M, T.

2015-10-01

The X-ray equipment for diagnosis comes in different sizes and shapes depending on the scan type to perform. The X-ray spectrum is the energy distribution of the beam photons and consists of a continuous spectrum of photons braking and discrete spectrum due to the characteristic photons. The knowledge of the X-rays spectrum is important to understand like they affect the voltage changes (k Vp), current (m A), time (s) and the type of filter in the interaction mechanisms between X-rays and patient's body, the image receptor or other material that gets in the beam. Across the spectrum can be estimated the absorbed dose in any point of the patient, the quality of the image and the scattered radiation (which is related to the dose received by the equipment operator). The Monte Carlo method was used by MCNP5 code to calculate the spectrum of X-rays that occurs when a monoenergetic electron beam of 250 keV interact with targets of Mo, Rh and W. The spectra were calculated with and without filter, and the values of ambient dose equivalent were estimated, as well as the air kerma. (Author)

Ensemble simulations with discrete classical dynamics

DEFF Research Database (Denmark)

Toxværd, Søren

2013-01-01

For discrete classical Molecular dynamics (MD) obtained by the "Verlet" algorithm (VA) with the time increment $h$ there exist a shadow Hamiltonian $\\tilde{H}$ with energy $\\tilde{E}(h)$, for which the discrete particle positions lie on the analytic trajectories for $\\tilde{H}$. $\\tilde......{E}(h)$ is employed to determine the relation with the corresponding energy, $E$ for the analytic dynamics with $h=0$ and the zero-order estimate $E_0(h)$ of the energy for discrete dynamics, appearing in the literature for MD with VA. We derive a corresponding time reversible VA algorithm for canonical dynamics...

Spectrum sensing algorithm based on autocorrelation energy in cognitive radio networks

Science.gov (United States)

Ren, Shengwei; Zhang, Li; Zhang, Shibing

2016-10-01

Cognitive radio networks have wide applications in the smart home, personal communications and other wireless communication. Spectrum sensing is the main challenge in cognitive radios. This paper proposes a new spectrum sensing algorithm which is based on the autocorrelation energy of signal received. By taking the autocorrelation energy of the received signal as the statistics of spectrum sensing, the effect of the channel noise on the detection performance is reduced. Simulation results show that the algorithm is effective and performs well in low signal-to-noise ratio. Compared with the maximum generalized eigenvalue detection (MGED) algorithm, function of covariance matrix based detection (FMD) algorithm and autocorrelation-based detection (AD) algorithm, the proposed algorithm has 2 11 dB advantage.

Energy spectrum of Compton scattering of laser photons on relativistic electrons

International Nuclear Information System (INIS)

Ando, Hiroaki; Yoneda, Yasuharu

1976-01-01

The high energy photons in gamma-ray region are obtainable by the Compton scattering of laser photons on relativistic electrons. But the motion of the electrons in the storage ring is not necessarily uniform. In the study of the uneven effect, the energy distribution of scattered photons is derived from the assumed momentum distribution of incident electrons. It is generally impossible to derive the momentum distribution of incident electrons from the energy spectrum of scattered photons. The additional conditions which make this possible in a special case are considered. A calculational method is examined for deriving the energy spectrum of scattered photons from the assumed momentum distribution of incident electrons. (Mori, K.)

Energy spectrum of argon ions emitted from Filippov type Sahand plasma focus

International Nuclear Information System (INIS)

Mohammadnejad, M.; Pestehe, S. J.; Mohammadi, M. A.

2013-01-01

The energy and flux of the argon ions produced in Sahand plasma focus have been measured by employing a well-designed Faraday cup. The secondary electron emission effects on the ion signals are simulated and the dimensions of Faraday cup are optimized to minimize these effects. The measured ion energy spectrum is corrected for the ion energy loss and charge exchange in the background gas. The effects of the capacitor bank voltage and working gas pressure on the ion energy spectrum are also investigated. It has been shown that the emitted ion number per energy increases as the capacitor bank voltage increases. Decreasing the working gas pressure leads to the increase in the number of emitted ion per energy

Energy-efficient routing, modulation and spectrum allocation in elastic optical networks

Science.gov (United States)

Tan, Yanxia; Gu, Rentao; Ji, Yuefeng

2017-07-01

With tremendous growth in bandwidth demand, energy consumption problem in elastic optical networks (EONs) becomes a hot topic with wide concern. The sliceable bandwidth-variable transponder in EON, which can transmit/receive multiple optical flows, was recently proposed to improve a transponder's flexibility and save energy. In this paper, energy-efficient routing, modulation and spectrum allocation (EE-RMSA) in EONs with sliceable bandwidth-variable transponder is studied. To decrease the energy consumption, we develop a Mixed Integer Linear Programming (MILP) model with corresponding EE-RMSA algorithm for EONs. The MILP model jointly considers the modulation format and optical grooming in the process of routing and spectrum allocation with the objective of minimizing the energy consumption. With the help of genetic operators, the EE-RMSA algorithm iteratively optimizes the feasible routing path, modulation format and spectrum resources solutions by explore the whole search space. In order to save energy, the optical-layer grooming strategy is designed to transmit the lightpath requests. Finally, simulation results verify that the proposed scheme is able to reduce the energy consumption of the network while maintaining the blocking probability (BP) performance compare with the existing First-Fit-KSP algorithm, Iterative Flipping algorithm and EAMGSP algorithm especially in large network topology. Our results also demonstrate that the proposed EE-RMSA algorithm achieves almost the same performance as MILP on an 8-node network.

Perturbation of operators and approximation of spectrum

Indian Academy of Sciences (India)

outside the bounds of essential spectrum of A(x) can be approximated ... some perturbed discrete Schrödinger operators treating them as block ...... particular, one may think of estimating the spectrum and spectral gaps of Schrödinger.

Hard x-ray to low energy gamma ray spectrum of the Crab Nebula

International Nuclear Information System (INIS)

Jung, G.V.

1986-01-01

The spectrum of the Crab Nebula has been determined in the energy range 10 keV to 5 MeV from the data of the UCSD/MIT Hard-X-ray and Low Energy Gamma Ray Experiment on the first High Energy Astronomy Observatory, HEAO-1. The x-ray to γ-ray portion of the continuous emission from the Crab is indicative of the electron spectrum, its transport through the nebula, and the physical conditions near the shocked interface between the nebular region and the wind which is the physical link between the nebula and the pulsar, NP0532. The power-law dependence of the spectrum found in the lower-energy decade of this observation (10 to 100 keV) is not continued without modification to higher energies. Evidence for this has been accumulating from previous observations in the γ-ray ranges of 1-10 MeV and above 35 MeV. The observations on which this dissertation is based further characterize the spectral change in the 100 keV to 1 MeV region. These observations provide a crucial connection between the x-ray and γ-ray spectrum of the non-pulsed emission of the Crab Nebula. The continuity of this spectrum suggests that the emission mechanism responsible for the non-pulsed γ-rays observed above 35 MeV is of the same origin as the emission at lower energies, i.e. that of synchrotron radiation in the magnetic field of the nebula

Hofstadter's butterfly energy spectrum of ultracold fermions on the two-dimensional triangular optical lattice

International Nuclear Information System (INIS)

Hou Jingmin; Lu Qingqing

2009-01-01

We study the energy spectrum of ultracold fermionic atoms on the two-dimensional triangular optical lattice subjected to a perpendicular effective magnetic field, which can be realized with laser beams. We derive the generalized Harper's equations and numerically solve them, then we obtain the Hofstadter's butterfly-like energy spectrum, which has a novel fractal structure. The observability of the Hofstadter's butterfly spectrum is also discussed

Characterization of the Photon Energy Spectrum of a 6 MV Linac

International Nuclear Information System (INIS)

Hernandez Bojorquez, M.; Larraga, J. M.; Garcia, A.; Celis, M. A.; Martinez-Davalos, A.; Rodriguez-Villafuerte, M.

2006-01-01

In this work we study the influence of the purity of the materials used in experimental transmission measurements to obtain data to reconstruct the photon energy spectrum of a 6 MV Linac. We also evaluate the contribution to PDDs due to electron contamination in the reconstructed spectrum

Wavelet Spatial Energy Spectrums Studies on Drag Reduction by Micro-bubble Injection

International Nuclear Information System (INIS)

Ling Zhen; Yassin Hassan

2006-01-01

In this study, continuous wavelet transforms and spatial correlation techniques are employed to determine the space-localized wavenumber energy spectrum of the velocity signals in turbulent channel flow. The flow conditions correspond to single phase flow and micro-bubbles injected two phase flow. The wavelet energy spectrums demonstrate that the wavenumber (eddy size) content of the velocity signals is not only space-dependent but also micro-bubbles can impact the eddy size content. Visual observations of the wavelet energy spectrum spatial distribution was realized by using Particle Image Velocimetry (PIV) measurement technique. The two phase flow condition corresponds to a drag reduction of 38.4% with void fraction of 4.9%. The present results provide evidence that micro-bubbles in the boundary layer of a turbulent channel flow can help adjust the eddy size distributions near the wall. This can assist in explaining that micro-bubbles are performing as buffers to keep the energy of fluid particles going in stream-wise direction and reducing the energy of fluid particles going in normal direction. (authors)

Condensing Raman spectrum for single-cell phenotype analysis

KAUST Repository

Sun, Shiwei

2015-12-09

Background In recent years, high throughput and non-invasive Raman spectrometry technique has matured as an effective approach to identification of individual cells by species, even in complex, mixed populations. Raman profiling is an appealing optical microscopic method to achieve this. To fully utilize Raman proling for single-cell analysis, an extensive understanding of Raman spectra is necessary to answer questions such as which filtering methodologies are effective for pre-processing of Raman spectra, what strains can be distinguished by Raman spectra, and what features serve best as Raman-based biomarkers for single-cells, etc. Results In this work, we have proposed an approach called rDisc to discretize the original Raman spectrum into only a few (usually less than 20) representative peaks (Raman shifts). The approach has advantages in removing noises, and condensing the original spectrum. In particular, effective signal processing procedures were designed to eliminate noise, utilising wavelet transform denoising, baseline correction, and signal normalization. In the discretizing process, representative peaks were selected to signicantly decrease the Raman data size. More importantly, the selected peaks are chosen as suitable to serve as key biological markers to differentiate species and other cellular features. Additionally, the classication performance of discretized spectra was found to be comparable to full spectrum having more than 1000 Raman shifts. Overall, the discretized spectrum needs about 5storage space of a full spectrum and the processing speed is considerably faster. This makes rDisc clearly superior to other methods for single-cell classication.

Spectrum and energy levels of four-times-ionized niobium

International Nuclear Information System (INIS)

Kagan, D.T.; Conway, J.G.; Meinders, E.

1981-01-01

The 4p 6 nl spectrum of Nb 4+ was measured and analyzed. The spectrum was excited in a vacuum sliding spark source with a peak current of 800 A and a pulse width of 70 μsec. The analysis of the spectrum has extended the 12 known lines to 84 and the 10 known levels to 30. The ionization energy was calculated to be 407897 +- 40 cm -1 . There is strong evidence that the 4p 5 4d 2 configurations interacts strongly with the 4p 6 nf configuration. In addition, the hyperfine splitting of the 4p 6 6s level has been observed and measured to be 1.1 cm -1

Measurement of the ν{sub μ} energy spectrum with IceCube-79

Energy Technology Data Exchange (ETDEWEB)

Aartsen, M.G.; Hill, G.C.; Kyriacou, A.; Robertson, S.; Wallace, A.; Whelan, B.J. [University of Adelaide, Department of Physics, Adelaide (Australia); Ackermann, M.; Bernardini, E.; Blot, S.; Bradascio, F.; Bretz, H.P.; Franckowiak, A.; Jacobi, E.; Karg, T.; Kintscher, T.; Kunwar, S.; Nahnhauer, R.; Satalecka, K.; Spiering, C.; Stachurska, J.; Stasik, A.; Strotjohann, N.L.; Terliuk, A.; Usner, M.; Santen, J. van [DESY, Zeuthen (Germany); Adams, J.; Bagherpour, H. [University of Canterbury, Department of Physics and Astronomy, Christchurch (New Zealand); Aguilar, J.A.; Ansseau, I.; Heereman, D.; Meagher, K.; Meures, T.; O' Murchadha, A.; Pinat, E.; Raab, C. [Universite Libre de Bruxelles, Science Faculty CP230, Brussels (Belgium); Ahlers, M.; Braun, J.; Chirkin, D.; Day, M.; Desiati, P.; Diaz-Velez, J.C.; Fahey, S.; Feintzeig, J.; Ghorbani, K.; Gladstone, L.; Griffith, Z.; Halzen, F.; Hanson, K.; Hoshina, K.; Jero, K.; Karle, A.; Kauer, M.; Kelley, J.L.; Kheirandish, A.; Krueger, C.; Mancina, S.; McNally, F.; Merino, G.; Sabbatini, L.; Tobin, M.N.; Tosi, D.; Vandenbroucke, J.; Van Rossem, M.; Wandkowsky, N.; Wendt, C.; Westerhoff, S.; Wille, L.; Xu, D.L. [University of Wisconsin, Department of Physics and Wisconsin IceCube Particle Astrophysics Center, Madison, WI (United States); Ahrens, M.; Bohm, C.; Dumm, J.P.; Finley, C.; Flis, S.; Hultqvist, K.; Walck, C.; Wolf, M.; Zoll, M. [Stockholm University, Department of Physics, Oskar Klein Centre, Stockholm (Sweden); Al Samarai, I.; Bron, S.; Carver, T.; Christov, A.; Montaruli, T. [Universite de Geneve, Departement de physique nucleaire et corpusculaire, Geneva (Switzerland); Altmann, D.; Anton, G.; Gluesenkamp, T.; Katz, U.; Kittler, T.; Tselengidou, M. [Friedrich-Alexander-Universitaet Erlangen-Nuernberg, Erlangen Centre for Astroparticle Physics, Erlangen (Germany); Andeen, K. [Marquette University, Department of Physics, Milwaukee, WI (United States); Anderson, T.; Dunkman, M.; Eller, P.; Huang, F.; Keivani, A.; Lanfranchi, J.L.; Pankova, D.V.; Quinnan, M.; Tesic, G.; Weiss, M.J. [Pennsylvania State University, Department of Physics, University Park, PA (United States); Archinger, M.; Baum, V.; Boeser, S.; Del Pino Rosendo, E.; Di Lorenzo, V.; Eberhardt, B.; Ehrhardt, T.; Foesig, C.C.; Koepke, L.; Krueckl, G.; Momente, G.; Peiffer, P.; Sandroos, J.; Steuer, A.; Wiebe, K. [University of Mainz, Institute of Physics, Mainz (Germany); Argueelles, C.; Axani, S.; Collin, G.H.; Conrad, J.M.; Jones, B.J.P.; Moulai, M. [Massachusetts Institute of Technology, Department of Physics, Cambridge, MA (United States); Auffenberg, J.; Glauch, T.; Haack, C.; Hansmann, T.; Konietz, R.; Leuermann, M.; Penek, Oe.; Raedel, L.; Reimann, R.; Rongen, M.; Schoenen, S.; Schumacher, L.; Stettner, J.; Vehring, M.; Vogel, E.; Wallraff, M.; Waza, A.; Wickmann, S.; Wiebusch, C.H. [RWTH Aachen University, III. Physikalisches Institut, Aachen (Germany); Bai, X. [South Dakota School of Mines and Technology, Physics Department, Rapid City, SD (United States); Barwick, S.W.; Yodh, G. [University of California, Department of Physics and Astronomy, Irvine, CA (United States); Bay, R.; Filimonov, K.; Price, P.B.; Woschnagg, K. [University of California, Department of Physics, Berkeley, CA (United States); Beatty, J.J. [Ohio State University, Department of Physics and Center for Cosmology and Astro-Particle Physics, Columbus, OH (United States); Ohio State University, Department of Astronomy, Columbus, OH (United States); Becker Tjus, J.; Bos, F.; Eichmann, B.; Kroll, M.; Schoeneberg, S.; Tenholt, F. [Ruhr-Universitaet Bochum, Fakultaet fuer Physik and Astronomie, Bochum (Germany); Becker, K.H.; Bindig, D.; Helbing, K.; Hickford, S.; Hoffmann, R.; Kopper, S.; Lauber, F.; Naumann, U.; Obertacke Pollmann, A.; Soldin, D. [University of Wuppertal, Department of Physics, Wuppertal (Germany); BenZvi, S.; Cross, R. [University of Rochester, Department of Physics and Astronomy, Rochester, NY (United States); Berley, D.; Blaufuss, E.; Cheung, E.; Felde, J.; Friedman, E.; Hellauer, R.; Hoffman, K.D.; Maunu, R.; Olivas, A.; Schmidt, T.; Song, M.; Sullivan, G.W. [University of Maryland, Department of Physics, College Park, MD (United States); Besson, D.Z. [University of Kansas, Department of Physics and Astronomy, Lawrence, KS (United States); Binder, G.; Gerhardt, L.; Klein, S.R.; Miarecki, S.; Palczewski, T.; Tatar, J. [University of California, Department of Physics, Berkeley, CA (United States); Lawrence Berkeley National Laboratory, Berkeley, CA (United States); Boerner, M.; Fuchs, T.; Meier, M.; Menne, T.; Pieloth, D.; Rhode, W.; Ruhe, T.; Sandrock, A.; Schlunder, P. [TU Dortmund University, Department of Physics, Dortmund (Germany); Collaboration: IceCube Collaboration; and others

2017-10-15

IceCube is a neutrino observatory deployed in the glacial ice at the geographic South Pole. The ν{sub μ} energy unfolding described in this paper is based on data taken with IceCube in its 79-string configuration. A sample of muon neutrino charged-current interactions with a purity of 99.5% was selected by means of a multivariate classification process based on machine learning. The subsequent unfolding was performed using the software Truee. The resulting spectrum covers an E{sub ν}-range of more than four orders of magnitude from 125 GeV to 3.2 PeV. Compared to the Honda atmospheric neutrino flux model, the energy spectrum shows an excess of more than 1.9σ in four adjacent bins for neutrino energies E{sub ν} ≥ 177.8 TeV. The obtained spectrum is fully compatible with previous measurements of the atmospheric neutrino flux and recent IceCube measurements of a flux of high-energy astrophysical neutrinos. (orig.)

Quantification of discreteness effects in cosmological N-body simulations: Initial conditions

International Nuclear Information System (INIS)

Joyce, M.; Marcos, B.

2007-01-01

The relation between the results of cosmological N-body simulations, and the continuum theoretical models they simulate, is currently not understood in a way which allows a quantification of N dependent effects. In this first of a series of papers on this issue, we consider the quantification of such effects in the initial conditions of such simulations. A general formalism developed in [A. Gabrielli, Phys. Rev. E 70, 066131 (2004).] allows us to write down an exact expression for the power spectrum of the point distributions generated by the standard algorithm for generating such initial conditions. Expanded perturbatively in the amplitude of the input (i.e. theoretical, continuum) power spectrum, we obtain at linear order the input power spectrum, plus two terms which arise from discreteness and contribute at large wave numbers. For cosmological type power spectra, one obtains as expected, the input spectrum for wave numbers k smaller than that characteristic of the discreteness. The comparison of real space correlation properties is more subtle because the discreteness corrections are not as strongly localized in real space. For cosmological type spectra the theoretical mass variance in spheres and two-point correlation function are well approximated above a finite distance. For typical initial amplitudes this distance is a few times the interparticle distance, but it diverges as this amplitude (or, equivalently, the initial redshift of the cosmological simulation) goes to zero, at fixed particle density. We discuss briefly the physical significance of these discreteness terms in the initial conditions, in particular, with respect to the definition of the continuum limit of N-body simulations

Decay energy of 55Fe from its inner Bremsstrahlung spectrum

Science.gov (United States)

Keshava, S. L.; Gopala, K.; Venkataramaiah, P.

2001-06-01

Several measurements of decay energy using the inner Bremsstrahlung spectrum (IB) due to radiative electron capture in 55Fe has been made. But the results are not uniform. Hence another attempt has been made at the same. Experimental data was obtained with a 4.445 cm. dia ' 5.08 cm thick NaI (Tl) detector. It was subjected to suitable statistical treatment and various corrections using Liden and Starfelt procedure. The corrected spectrum agrees well with the Glauber and Martin theory for 1s electron capture beyond 100 keV. From the Jauch plot, the decay energy of 232.36 +/-0.64 keV was obtained.

Decay energy of 55Fe from its inner Bremsstrahlung spectrum

International Nuclear Information System (INIS)

Keshava, S.L.; Gopala, K.; Venkataramaiah, P.

2001-01-01

Several measurements of decay energy using the inner Bremsstrahlung spectrum (IB) due to radiative electron capture in 55 Fe has been made. But the results are not uniform. Hence another attempt has been made at the same. Experimental data was obtained with a 4.445 cm dia x 5.08 cm thick NaI (Tl) detector. It was subjected to suitable statistical treatment and various corrections using Liden and Starfelt procedure. The corrected spectrum agrees well with the Glauber and Martin theory for l s electron capture beyond 100 keV. From the Jauch plot, the decay energy of 232.36±0.64 keV was obtained. (author)

D{sup -} energy spectrum in toroidal quantum ring

Energy Technology Data Exchange (ETDEWEB)

Gomez, C A; Gutierrez, W; Garcia, L F [Universidad Industrial de Santander, Bucaramanga (Colombia); Marin, J H, E-mail: jhmarin@unal.edu.c [Universidad Nacional-Colombia, Medellin-Colombia, AA3840 (Colombia)

2009-05-01

The structure of energy spectrum of the negative donor centre in a toroidal-shaped quantum ring with two different morphologies of the cross-section is analyzed. By using the adiabatic procedure we have deduced a one-dimensional wave equation with periodic conditions which describes the low-lying energy levels related to the electrons rotation around the symmetry axis. Our results are in good agreement with those previously obtained as the size of the ring cross-section tends to zero.

NREL Spectrum of Clean Energy Innovation: Issue 3 (Book)

Energy Technology Data Exchange (ETDEWEB)

2012-11-01

This quarterly magazine is dedicated to stepping beyond the technical journals to reveal NREL's vital work in a real-world context for our stakeholders. Continuum provides insights into the latest and most impactful clean energy innovations, while spotlighting those talented researchers and unique facilities that make it all happen. This edition focuses on the NREL Spectrum of Clean Energy Innovation.

Discrete Bose-Einstein systems in a box with low adiabatic invariant

International Nuclear Information System (INIS)

Vlad, V.I.; Ionescu-Pallas, N.

2002-03-01

The Bose-Einstein energy spectrum of a quantum gas, confined in a (cubic) box, is discrete and strongly dependent on the box geometry and temperature, for low product of the atomic mass number, A at and the adiabatic invariant, TV 2/3 , i.e. on γ=A at TV 2/3 . Even within the approximation of noninteracting particles in the gas, the calculation of the thermodynamic properties of Bose-Einstein systems turns out to be a difficult mathematical problem. It is solved in the textbooks and most papers by approximating the sums by integrals. The present study compares the total number of particles and the total energy obtained by summing up the exact contributions of the eigenvalues and their weights, for defined values of γ, to the results of the approximate integrals. Then, the passage from sums to integrals is done in a more rigorous manner and better analytical approximations are found. The corrected thermodynamic functions depend on γ. The critical temperature is corrected also in order to describe more accurately the discrete Bose-Einstein systems and their onset of the phase transition. (author)

Modeling energy market dynamics using discrete event system simulation

International Nuclear Information System (INIS)

Gutierrez-Alcaraz, G.; Sheble, G.B.

2009-01-01

This paper proposes the use of Discrete Event System Simulation to study the interactions among fuel and electricity markets and consumers, and the decision-making processes of fuel companies (FUELCOs), generation companies (GENCOs), and consumers in a simple artificial energy market. In reality, since markets can reach a stable equilibrium or fail, it is important to observe how they behave in a dynamic framework. We consider a Nash-Cournot model in which marketers are depicted as Nash-Cournot players that determine supply to meet end-use consumption. Detailed engineering considerations such as transportation network flows are omitted, because the focus is upon the selection and use of appropriate market models to provide answers to policy questions. (author)

Experimental verification of microbending theory using mode coupling to discrete cladding modes

DEFF Research Database (Denmark)

Probst, C. B.; Bjarklev, Anders Overgaard; Andreasen, S. B.

1989-01-01

a microbending theory in which coupling between the guided mode and a number of discrete cladding modes is considered. Very good agreement between theory and measurement is achieved. The consequences of the existence of discrete cladding modes with regard to the proper choice of artificial microbending spectrum...

Ground level enhancement (GLE) energy spectrum parameters model

Science.gov (United States)

Qin, G.; Wu, S.

2017-12-01

We study the ground level enhancement (GLE) events in solar cycle 23 with the four energy spectra parameters, the normalization parameter C, low-energy power-law slope γ 1, high-energy power-law slope γ 2, and break energy E0, obtained by Mewaldt et al. 2012 who fit the observations to the double power-law equation. we divide the GLEs into two groups, one with strong acceleration by interplanetary (IP) shocks and another one without strong acceleration according to the condition of solar eruptions. We next fit the four parameters with solar event conditions to get models of the parameters for the two groups of GLEs separately. So that we would establish a model of energy spectrum for GLEs for the future space weather prediction.

Neutron energy spectrum influence on irradiation hardening and microstructural development of tungsten

Energy Technology Data Exchange (ETDEWEB)

Fukuda, Makoto, E-mail: makoto.fukuda@qse.tohoku.ac.jp [Tohoku University, Sendai, 980-8579 (Japan); Kiran Kumar, N.A.P.; Koyanagi, Takaaki; Garrison, Lauren M. [Oak Ridge National Laboratory, Oak Ridge, TN, 37831 (United States); Snead, Lance L. [Massachusetts Institute of Technology, Cambridge, MA, 02139 (United States); Katoh, Yutai [Oak Ridge National Laboratory, Oak Ridge, TN, 37831 (United States); Hasegawa, Akira [Tohoku University, Sendai, 980-8579 (Japan)

2016-10-15

Neutron irradiation to single crystal pure tungsten was performed in the mixed spectrum High Flux Isotope Reactor (HFIR). To investigate the influences of neutron energy spectrum, the microstructure and irradiation hardening were compared with previous data obtained from the irradiation campaigns in the mixed spectrum Japan Material Testing Reactor (JMTR) and the sodium-cooled fast reactor Joyo. The irradiation temperatures were in the range of ∼90–∼800 °C and fast neutron fluences were 0.02–9.00 × 10{sup 25} n/m{sup 2} (E > 0.1 MeV). Post irradiation evaluation included Vickers hardness measurements and transmission electron microscopy. The hardness and microstructure changes exhibited a clear dependence on the neutron energy spectrum. The hardness appeared to increase with increasing thermal neutron flux when fast fluence exceeds 1 × 10{sup 25} n/m{sup 2} (E > 0.1 MeV). Irradiation induced precipitates considered to be χ- and σ-phases were observed in samples irradiated to >1 × 10{sup 25} n/m{sup 2} (E > 0.1 MeV), which were pronounced at high dose and due to the very high thermal neutron flux of HFIR. Although the irradiation hardening mainly caused by defects clusters in a low dose regime, the transmutation-induced precipitation appeared to impose additional significant hardening of the tungsten. - Highlights: • The microstructure and irradiation hardening of single crystal pure W irradiated in HFIR was investigated. • The neutron energy spectrum influence was evaluated by comparing the HFIR results with previous work in Joyo and JMTR. • In the dose range up to ∼1 dpa, the neutron energy spectrum influence of irradiation hardening was not clear. • In the dose range above 1 dpa, the neutron energy influence on irradiation hardening and microstructural development was clearly observed. • The irradiation induced precipitates caused significant irradiation hardening of pure W irradiated in HFIR.

Evolution of the near-UV emission spectrum associated with the reduction process in microwave iron making.

Science.gov (United States)

Matsubara, Akihiro; Takayama, Sadatsugu; Okajima, Shigeki; Sato, Motoyasu

2008-01-01

The structure of the emission spectrum in the near-UV range (240 nm-310 nm) changes drastically from the continuous spectrum to a discrete line spectrum with increasing sample temperature during the carbothermic reduction of magnetite in a 2.45 GHz microwave multimode furnace. The continuous spectrum can be assigned as a cathodoluminescence of magnetite. The dynamic evolution of the spectrum from continuous to discrete represents the progress of the reduction from magnetite to iron.

Improving Energy Efficiency for the Vehicle Assembly Industry: A Discrete Event Simulation Approach

Science.gov (United States)

Oumer, Abduaziz; Mekbib Atnaw, Samson; Kie Cheng, Jack; Singh, Lakveer

2016-11-01

This paper presented a Discrete Event Simulation (DES) model for investigating and improving energy efficiency in vehicle assembly line. The car manufacturing industry is one of the highest energy consuming industries. Using Rockwell Arena DES package; a detailed model was constructed for an actual vehicle assembly plant. The sources of energy considered in this research are electricity and fuel; which are the two main types of energy sources used in a typical vehicle assembly plant. The model depicts the performance measurement for process- specific energy measures of painting, welding, and assembling processes. Sound energy efficiency model within this industry has two-fold advantage: reducing CO2 emission and cost reduction associated with fuel and electricity consumption. The paper starts with an overview of challenges in energy consumption within the facilities of automotive assembly line and highlights the parameters for energy efficiency. The results of the simulation model indicated improvements for energy saving objectives and reduced costs.

Magnetic field effects on the quantum wire energy spectrum and Green's function

International Nuclear Information System (INIS)

Morgenstern Horing, Norman J.

2010-01-01

We analyze the energy spectrum and propagation of electrons in a quantum wire on a 2D host medium in a normal magnetic field, representing the wire by a 1D Dirac delta function potential which would support just a single subband state in the absence of the magnetic field. The associated Schroedinger Green's function for the quantum wire is derived in closed form in terms of known functions and the Landau quantized subband energy spectrum is examined.

Spectrum and energy levels of five-times ionized zirconium (Zr VI)

Science.gov (United States)

Reader, Joseph; Lindsay, Mark D.

2016-02-01

We carried out a new analysis of the spectrum of five-times-ionized zirconium Zr VI. For this we used sliding-spark discharges together with normal- and grazing-incidence spectrographs to observe the spectrum from 160 to 2000 Å. These observations showed that the analysis of this spectrum by Khan et al (1985 Phys. Scr. 31 837) contained a significant number of incorrect energy levels. We have now classified ˜420 lines as transitions between 23 even-parity levels 73 odd-parity levels. The 4s24p5, 4s4p6, 4s24p44d, 5s, 5d, 6s configurations are now complete, although a few levels of 4s24p45d are tentative. We determined Ritz-type wavelengths for ˜135 lines from the optimized energy levels. The uncertainties range from 0.0003 to 0.0020 Å. Hartree-Fock calculations and least-squares fits of the energy parameters to the observed levels were used to interpret the observed configurations. Oscillator strengths for all classified lines were calculated with the fitted parameters. The results are compared with values for the level energies, percentage compositions, and transition probabilities from recent ab initio theoretical calculations. The ionization energy was revised to 777 380 ± 300 cm-1 (96.38 ± 0.04 eV).

Application of thermoluminescence dosimeter on the measurement of hard X-ray pulse energy spectrum

International Nuclear Information System (INIS)

Song Zhaohui; Wang Baohui; Wang Kuilu; Hei Dongwei; Sun Fengrong; Li Gang

2003-01-01

This paper introduces the application of thermoluminescence dosimeter (TLD) which composed by TLD-3500 reader and GR-100 M chips on the measurement of hard X-ray pulse energy spectrum. The idea using Filter Fluorescence Method (FFM) and TLD to measure hard X-ray pulse energy spectrum (from 10 keV to 100 keV) is discussed in details. Considering all the factors of the measuring surrounding, the measurement system of hard X-ray pulse has been devised. The calibration technique of absolute energy response of TLD is established. This method has been applied successfully on the radiation parameters measurement of the huge pulse radiation device-high-power pulser I. Hard X-ray pulse energy spectrum data of the pulser are acquired

Energy spectrum measurement of high power and high energy(6 and 9 MeV) pulsed x-ray source for industrial use

Energy Technology Data Exchange (ETDEWEB)

Takagi, Hiroyuki [Hitachi, Ltd. Power Systems Company, Ibaraki (Japan); Murata, Isao [Graduate School of Engineering, Osaka University, Osaka (Japan)

2016-06-15

Industrial X-ray CT system is normally applied to non-destructive testing (NDT) for industrial product made from metal. Furthermore there are some special CT systems, which have an ability to inspect nuclear fuel assemblies or rocket motors, using high power and high energy (more than 6 MeV) pulsed X-ray source. In these case, pulsed X-ray are produced by the electron linear accelerator, and a huge number of photons with a wide energy spectrum are produced within a very short period. Consequently, it is difficult to measure the X-ray energy spectrum for such accelerator-based X-ray sources using simple spectrometry. Due to this difficulty, unexpected images and artifacts which lead to incorrect density information and dimensions of specimens cannot be avoided in CT images. For getting highly precise CT images, it is important to know the precise energy spectrum of emitted X-rays. In order to realize it we investigated a new approach utilizing the Bayesian estimation method combined with an attenuation curve measurement using step shaped attenuation material. This method was validated by precise measurement of energy spectrum from a 1 MeV electron accelerator. In this study, to extend the applicable X-ray energy range we tried to measure energy spectra of X-ray sources from 6 and 9 MeV linear accelerators by using the recently developed method. In this study, an attenuation curves are measured by using a step-shaped attenuation materials of aluminum and steel individually, and the each X-ray spectrum is reconstructed from the measured attenuation curve by the spectrum type Bayesian estimation method. The obtained result shows good agreement with simulated spectra, and the presently developed technique is adaptable for high energy X-ray source more than 6 MeV.

Construction of energy loss function for low-energy electrons in helium

Energy Technology Data Exchange (ETDEWEB)

Dayashankar, [Bhabha Atomic Research Centre, Bombay (India). Div. of Radiation Protection

1976-02-01

The energy loss function for electrons in the energy range from 50 eV to 1 keV in helium gas has been constructed by considering separately the energy loss in overcoming the ionization threshold, the loss manifested as kinetic energy of secondary electrons and the loss in the discrete state excitations. This has been done by utilizing recent measurements of Opal et al. on the energy spectrum of secondary electrons and incorporating the experimental data on cross sections for twenty-four excited states. The present results of the energy loss function are in good agreement with the Bethe formula for energies above 500 eV. For lower energies, where the Bethe formula is not applicable, the present results should be particularly useful.

Spectrum and energy levels of kryptonlike ion Nb VI

International Nuclear Information System (INIS)

Reader, J.; Ekberg, J.O.

1993-01-01

The spectrum of five-times ionized niobium, Nb, VI, was observed from 238 to 2700 angstrom with sliding spark discharges on 10.7-m normal- and grazing-incidence spectrographs. Experimental energies were determined for all levels of the 4s 2 4p 6 , 4s 2 4p 6 , 4s 2 4p 5 4d, 4f, 5s, 5p, 5g, 6s, and 4s4p 6 4d configurations as well as some levels of 4p 5 6g. A total of 291 lines were classified as transitions between 88 observed levels. A previous analysis of this spectrum was found to be totally erroneous. Large hyperfine splittings were found for several levels of the 4p 5 5s and 5p configurations. The observed configurations were theoretically interpreted by means of Hartree-Fock calculations and least squares fits of the energy parameters to the observed levels. A revised value of the ionization energy was obtained from the 4p 5 5g and 6g configurations

Model Predictive Control of a Wave Energy Converter with Discrete Fluid Power Power Take-Off System

DEFF Research Database (Denmark)

Hansen, Anders Hedegaard; Asmussen, Magnus Færing; Bech, Michael Møller

2018-01-01

Wave power extraction algorithms for wave energy converters are normally designed without taking system losses into account leading to suboptimal power extraction. In the current work, a model predictive power extraction algorithm is designed for a discretized power take of system. It is shown how...... the quantized nature of a discrete fluid power system may be included in a new model predictive control algorithm leading to a significant increase in the harvested power. A detailed investigation of the influence of the prediction horizon and the time step is reported. Furthermore, it is shown how...

A Laplace transform method for energy multigroup hybrid discrete ordinates

International Nuclear Information System (INIS)

Segatto, C.F.; Vilhena, M.T.; Barros, R.C.

2010-01-01

In typical lattice cells where a highly absorbing, small fuel element is embedded in the moderator, a large weakly absorbing medium, high-order transport methods become unnecessary. In this work we describe a hybrid discrete ordinates (S N) method for energy multigroup slab lattice calculations. This hybrid S N method combines the convenience of a low-order S N method in the moderator with a high-order S N method in the fuel. The idea is based on the fact that in weakly absorbing media whose physical size is several neutron mean free paths in extent, even the S 2 method (P 1 approximation), leads to an accurate result. We use special fuel-moderator interface conditions and the Laplace transform (LTS N ) analytical numerical method to calculate the two-energy group neutron flux distributions and the thermal disadvantage factor. We present numerical results for a range of typical model problems.

Algorithm for removing the noise from γ energy spectrum by analyzing the evolution of the wavelet transform maxima across scales

International Nuclear Information System (INIS)

Li Tianduo; Xiao Gang; Di Yuming; Han Feng; Qiu Xiaoling

1999-01-01

The γ energy spectrum is expanded in allied energy-frequency space. By the different characterization of the evolution of wavelet transform modulus maxima across scales between energy spectrum and noise, the algorithm for removing the noise from γ energy spectrum by analyzing the evolution of the wavelet transform maxima across scales is presented. The results show, in contrast to the methods in energy space or in frequency space, the method has the advantages that the peak of energy spectrum can be indicated accurately and the energy spectrum can be reconstructed with a good approximation

Spectrum-energy Correlations in GRBs: Update, Reliability, and the Long/Short Dichotomy

Science.gov (United States)

Zhang, Z. B.; Zhang, C. T.; Zhao, Y. X.; Luo, J. J.; Jiang, L. Y.; Wang, X. L.; Han, X. L.; Terheide, R. K.

2018-05-01

Spectrum-energy correlations of peak energy with total prompt γ-ray emission energies, namely {E}p,i-{E}{iso}, {E}p,i-{E}γ , and {E}p,i-{L}p, had been studied for long gamma-ray bursts (GRBs) previously by many authors. These energy correlations were proposed to measure the universe and classify GRBs as useful probes. However, most of these relations were built by non-Swift bursts. The spectrum-energy correlations of short bursts have not been systematically established yet; in particular, how the newly found GRB170817A matches these energy relations is unknown to date. We will first refresh the three spectrum-energy relations of Swift/BAT and Fermi/GBM long bursts and build the corresponding relations of short bursts. Then, we confirm whether they are commonly available as a discriminator of short and long GRBs. Some potential violators to these relations will be investigated. Combining with the plane of peak energy versus fluence, we select 31 short and 252 long GRBs with well-measured peak energy and redshift to study the issue of GRB classifications connected with the above energy relations statistically. We find that the three energy relations do exist in our new GRB samples and they are marginally consistent with some previous results. We report for the first time that short GRBs hold the three corresponding energy relations having the consistent power-law indices with long GRBs. It is found that these energy relations can be adopted to discriminate GRBs successfully if they are put in the peak energy versus fluence plane. Excitingly, we point out that GRB090510 matches the energy relations of {E}p,i-{E}{iso} and {E}p,i-{L}p, but violates the {E}p,i-{E}γ relation. More excitingly, we find that GRB170817A is an outlier to all the three energy correlations.

Discrete exterior calculus discretization of incompressible Navier–Stokes equations over surface simplicial meshes

KAUST Repository

Mohamed, Mamdouh S.

2016-02-11

A conservative discretization of incompressible Navier–Stokes equations is developed based on discrete exterior calculus (DEC). A distinguishing feature of our method is the use of an algebraic discretization of the interior product operator and a combinatorial discretization of the wedge product. The governing equations are first rewritten using the exterior calculus notation, replacing vector calculus differential operators by the exterior derivative, Hodge star and wedge product operators. The discretization is then carried out by substituting with the corresponding discrete operators based on the DEC framework. Numerical experiments for flows over surfaces reveal a second order accuracy for the developed scheme when using structured-triangular meshes, and first order accuracy for otherwise unstructured meshes. By construction, the method is conservative in that both mass and vorticity are conserved up to machine precision. The relative error in kinetic energy for inviscid flow test cases converges in a second order fashion with both the mesh size and the time step.

Discrete exterior calculus discretization of incompressible Navier-Stokes equations over surface simplicial meshes

Science.gov (United States)

Mohamed, Mamdouh S.; Hirani, Anil N.; Samtaney, Ravi

2016-05-01

A conservative discretization of incompressible Navier-Stokes equations is developed based on discrete exterior calculus (DEC). A distinguishing feature of our method is the use of an algebraic discretization of the interior product operator and a combinatorial discretization of the wedge product. The governing equations are first rewritten using the exterior calculus notation, replacing vector calculus differential operators by the exterior derivative, Hodge star and wedge product operators. The discretization is then carried out by substituting with the corresponding discrete operators based on the DEC framework. Numerical experiments for flows over surfaces reveal a second order accuracy for the developed scheme when using structured-triangular meshes, and first order accuracy for otherwise unstructured meshes. By construction, the method is conservative in that both mass and vorticity are conserved up to machine precision. The relative error in kinetic energy for inviscid flow test cases converges in a second order fashion with both the mesh size and the time step.

Scaling-law for the energy dependence of anatomic power spectrum in dedicated breast CT

Energy Technology Data Exchange (ETDEWEB)

Vedantham, Srinivasan; Shi, Linxi; Glick, Stephen J.; Karellas, Andrew [Department of Radiology, University of Massachusetts Medical School, Worcester, Massachusetts 01655 (United States)

2013-01-15

Purpose: To determine the x-ray photon energy dependence of the anatomic power spectrum of the breast when imaged with dedicated breast computed tomography (CT). Methods: A theoretical framework for scaling the empirically determined anatomic power spectrum at one x-ray photon energy to that at any given x-ray photon energy when imaged with dedicated breast CT was developed. Theory predicted that when the anatomic power spectrum is fitted with a power curve of the form k f{sup -{beta}}, where k and {beta} are fit coefficients and f is spatial frequency, the exponent {beta} would be independent of x-ray photon energy (E), and the amplitude k scales with the square of the difference in energy-dependent linear attenuation coefficients of fibroglandular and adipose tissues. Twenty mastectomy specimens based numerical phantoms that were previously imaged with a benchtop flat-panel cone-beam CT system were converted to 3D distribution of glandular weight fraction (f{sub g}) and were used to verify the theoretical findings. The 3D power spectrum was computed in terms of f{sub g} and after converting to linear attenuation coefficients at monoenergetic x-ray photon energies of 20-80 keV in 5 keV intervals. The 1D power spectra along the axes were extracted and fitted with a power curve of the form k f{sup -{beta}}. The energy dependence of k and {beta} were analyzed. Results: For the 20 mastectomy specimen based numerical phantoms used in the study, the exponent {beta} was found to be in the range of 2.34-2.42, depending on the axis of measurement. Numerical simulations agreed with the theoretical predictions that for a power-law anatomic spectrum of the form k f{sup -{beta}}, {beta} was independent of E and k(E) =k{sub 1}[{mu}{sub g}(E) -{mu}{sub a}(E)]{sup 2}, where k{sub 1} is a constant, and {mu}{sub g}(E) and {mu}{sub a}(E) represent the energy-dependent linear attenuation coefficients of fibroglandular and adipose tissues, respectively. Conclusions: Numerical

About the unitary discretizations of Heisenberg equations of motion

International Nuclear Information System (INIS)

Vazquez, L.

1986-01-01

In a recent paper Bender et al. (1985) have used a unitary discretization of Heisenberg equations for a one-dimensional quantum system in order to obtain information about the spectrum of the underlying continuum theory. The method consists in comparing the matrix elements between adjacent Fock states of the operators and at two steps. At the same time a very simple variational approach must be made. The purpose of this paper is to show that with unitary schemes, accurate either to order τ or τ 2 , we obtain the same spectrum results in the framework of the above method. On the other hand the same eigenvalues are obtained with a non-unitary scheme (Section II). In Section III we discuss the construction of the Hamiltonian associated to the unitary discretizations. (orig.)

Tolerance of continuous NFT spectrum to the optical fiber channel impairments

DEFF Research Database (Denmark)

Gaiarin, Simone; Da Ros, Francesco; Sørensen, Mads Peter

2016-01-01

The impact of launch power, additive white Gaussian noise and fiber loss on the nonlinear Fourier transform (NFT) continuous spectrum is investigated. NFT is shown to undergo lower spectral distortion than the discrete Fourier transform.......The impact of launch power, additive white Gaussian noise and fiber loss on the nonlinear Fourier transform (NFT) continuous spectrum is investigated. NFT is shown to undergo lower spectral distortion than the discrete Fourier transform....

Production of neutronic discrete equations for a cylindrical geometry in one group energy and benchmark the results with MCNP-4B code with one group energy library

International Nuclear Information System (INIS)

Salehi, A. A.; Vosoughi, N.; Shahriari, M.

2002-01-01

In reactor core neutronic calculations, we usually choose a control volume and investigate about the input, output, production and absorption inside it. Finally, we derive neutron transport equation. This equation is not easy to solve for simple and symmetrical geometry. The objective of this paper is to introduce a new direct method for neutronic calculations. This method is based on physics of problem and with meshing of the desired geometry, writing the balance equation for each mesh intervals and with notice to the conjunction between these mesh intervals, produce the final discrete equation series without production of neutron transport differential equation and mandatory passing form differential equation bridge. This method, which is named Direct Discrete Method, was applied in static state, for a cylindrical geometry in one group energy. The validity of the results from this new method are tested with MCNP-4B code with a one group energy library. One energy group direct discrete equation produces excellent results, which can be compared with the results of MCNP-4B

Spectrum and energy levels of five-times ionized zirconium (Zr VI)

International Nuclear Information System (INIS)

Reader, Joseph; Lindsay, Mark D

2016-01-01

We carried out a new analysis of the spectrum of five-times-ionized zirconium Zr VI. For this we used sliding-spark discharges together with normal- and grazing-incidence spectrographs to observe the spectrum from 160 to 2000 Å. These observations showed that the analysis of this spectrum by Khan et al (1985 Phys. Scr. 31 837) contained a significant number of incorrect energy levels. We have now classified ∼420 lines as transitions between 23 even-parity levels 73 odd-parity levels. The 4s 2 4p 5 , 4s4p 6 , 4s 2 4p 4 4d, 5s, 5d, 6s configurations are now complete, although a few levels of 4s 2 4p 4 5d are tentative. We determined Ritz-type wavelengths for ∼135 lines from the optimized energy levels. The uncertainties range from 0.0003 to 0.0020 Å. Hartree–Fock calculations and least-squares fits of the energy parameters to the observed levels were used to interpret the observed configurations. Oscillator strengths for all classified lines were calculated with the fitted parameters. The results are compared with values for the level energies, percentage compositions, and transition probabilities from recent ab initio theoretical calculations. The ionization energy was revised to 777 380 ± 300 cm −1 (96.38 ± 0.04 eV). (paper)

Reflection of the energy structure of a tungsten monocrystal nearsurface area in the secondary electron spectrum

International Nuclear Information System (INIS)

Artamonov, O.M.; Smirnov, O.M.; Terekhov, A.N.

1982-01-01

Formation of secondary electron energy spectrum during emission from the crystal layer near the surface has been considered, at that layer energy structure can be different from volumetric energy structure. Its thickness depends on the predominant mechanism of electron scattering and is determined by corresponding phenomenological parameters. It is shown that the structure in the secondary electron spectrum appears in the case when energy structure of emitting monocrystal layer can not be described in the approximation of almost free electron gas and, as experimental investigations show, approaches energy zone structure of its volume. It is also show that in the case when the energy structure of the emitting layer is satisfactorily described with the model of almost free electron gas, the SE spectrum is characterized with traditional cascade minimum. Experimental investigation of SE energy distribution was carried out for the W monocrystalline face (110). It was established that distinct structure in the SE spectrum appears only after electrochemical polishing of the specimen surface. It is related to the appearance of ''far'' order in the monocrystal emission layer on initially disturbed tungsten surface during such treatment. Disturbance of tungsten monocrystal surface structure on its oxidation in O 2 atmosphere results in the appearance of the cascade maximum and disappearance of distinct peculiarities in the SE spectrum

Discrete series representations for sl(2|1), Meixner polynomials and oscillator models

International Nuclear Information System (INIS)

Jafarov, E I; Van der Jeugt, J

2012-01-01

We explore a model for a one-dimensional quantum oscillator based on the Lie superalgebra sl(2|1). For this purpose, a class of discrete series representations of sl(2|1) is constructed, each representation characterized by a real number β > 0. In this model, the position and momentum operators of the oscillator are odd elements of sl(2|1) and their expressions involve an arbitrary parameter γ. In each representation, the spectrum of the Hamiltonian is the same as that of a canonical oscillator. The spectrum of a position operator can be continuous or infinite discrete, depending on the value of γ. We determine the position wavefunctions both in the continuous and the discrete case and discuss their properties. In the discrete case, these wavefunctions are given in terms of Meixner polynomials. From the embedding osp(1|2) subset of sl(2|1), it can be seen why the case γ = 1 corresponds to a paraboson oscillator. Consequently, taking the values (β, γ) = (1/2, 1) in the sl(2|1) model yields a canonical oscillator. (paper)

Inverse scattering with mixed spectrum from δ-potentials

International Nuclear Information System (INIS)

Lin Jiancheng.

1987-03-01

The inverse problem is studied in a system with mixed spectrum, i.e. the continuous part of the spectrum coincides with that of a repulsive δ-potential and the discrete part coincides with that of an attractive δ-potential. (author). 2 refs, 5 figs

Measurement of discrete energy-level spectra in individual chemically synthesized gold nanoparticles

DEFF Research Database (Denmark)

Kuemmeth, Ferdinand; Bolotin, Kirill I; Shi, Su-Fei

2008-01-01

We form single-electron transistors from individual chemically synthesized gold nanoparticles, 5-15 nm in diameter, with monolayers of organic molecules serving as tunnel barriers. These devices allow us to measure the discrete electronic energy levels of individual gold nanoparticles that are......, by virtue of chemical synthesis, well-defined in their composition, size and shape. We show that the nanoparticles are nonmagnetic and have spectra in good accord with random-matrix-theory predictions taking into account strong spin-orbit coupling....

U.S. Department Of Energy's nuclear engineering education research: highlights of recent and current research-II. 2. Advanced Finite Element Discretizations for High-Energy Ion Transport

International Nuclear Information System (INIS)

Gleicher, Frederick; Prinja, Anil K.

2001-01-01

An efficient multigroup model that accurately describes electronic energy loss straggling was recently presented for use in multigroup Monte Carlo and deterministic high-energy ion transport codes. The model preserves the mean energy loss per path length, using the continuous slowing down (CSD) approximation, and mean-squared energy loss per path length, using strictly down-scatter multigroup cross sections, and accurately captures the energy spectrum of an initially monoenergetic ion beam. However, the dominant CSD energy loss process coupled with the small (but non-negligible) straggling poses a significant challenge for deterministic numerical solution when incident beams are monoenergetic or have discontinuous energy spectra. Such spectra broaden very slowly with depth into the target material, and thus, the interior distributions display sharpness and discontinuities. Advanced space-energy discretization methods are consequently necessary to achieve numerical robustness. In this paper, we investigate finite element solutions to this problem using two general families of discontinuous trial functions, one linear and the other nonlinear. The two families have been numerically tested, and we show results for 1.7-GeV protons incident on a tungsten target. For benchmarking purposes, we have also performed Monte Carlo (MC) simulations. Figure 1 displays the spatially converged energy spectrum with 200 groups after the beam has penetrated two-thirds of the ion range (85 cm). We contrast results from linear (LD), bilinear (BLD), and quadratic (QD) discontinuous trail functions against those from exponential-linear (LE), exponential-bilinear (BLE), and exponential-quadratic (QE) discontinuous trail functions. It is clear that the linear and bilinear results from both families are grossly inaccurate, both showing unacceptably high numerical straggling when compared against the MC results. The nonlinear results are everywhere positive while the linear schemes display

A Spectrum Allocation Mechanism Based on HJ-DQPSO for Cognitive Radio Networks

Directory of Open Access Journals (Sweden)

Zhu Jiang

2015-11-01

Full Text Available In cognitive radio network model consisting of secondary users and primary users, in order to solve the difficult multi-objective spectrum allocation issue about maximizing network efficiency and users’ fairness to access network, this paper proposes a new discrete multi-objective combinatorial optimization mechanism—HJ-DQPSO based on Hooke Jeeves (HJ and Quantum Particle Swarm Optimization (QPSO algorithm. The mechanism adopts HJ algorithm to local search to prevent falling into the local optimum, and proposes a discrete QPSO algorithm to match the discrete spectrum assignment model. The mechanism has the advantages of approximating optimal solution, rapid convergence, less parameters, avoiding falling into local optimum. Compared with existing spectrum assignment algorithms, the simulation results show that according to different optimization objectives, the HJ-DQPSO optimization mechanism for multi-objective optimization can better approximate optimal solution and　converge fast. We can obtain a reasonable spectrum allocation scheme in the case of satisfying multiple optimization objectives.

Relaxation of ion energy spectrum just after turbulent heating pulse in TRIAM-1 tokamak

International Nuclear Information System (INIS)

Nakamura, Kazuo; Hiraki, Naoji; Nakamura, Yukio; Itoh, Satoshi

1982-01-01

The temporal evolution and spatial profile of the ion energy spectrum just after the application of a toroidal current pulse for turbulent heating are investigated experimentally in the TRIAM-1 tokamak and also numerically using the Fokker-Planck equation. The two-component ion energy spectrum formed by turbulent heating relaxes to a single one within tausub(i) (the ion collision time). (author)

Relaxation of ion energy spectrum just after turbulent heating pulse in TRIAM-1 tokamak

Energy Technology Data Exchange (ETDEWEB)

Nakamura, Kazuo; Hiraki, Naoji; Nakamura, Yukio; Itoh, Satoshi [Kyushu Univ., Fukuoka (Japan). Research Inst. for Applied Mechanics

1982-07-01

The temporal evolution and spatial profile of the ion energy spectrum just after the application of a toroidal current pulse for turbulent heating are investigated experimentally in the TRIAM-1 tokamak and also numerically using the Fokker-Planck equation. The two-component ion energy spectrum formed by turbulent heating relaxes to a single one within tausub(i) (the ion collision time).

Energy-level statistics and time relaxation in quantum systems

International Nuclear Information System (INIS)

Gruver, J.L.; Cerdeira, H.A.; Aliaga, J.; Mello, P.A.; Proto, A.N.

1997-05-01

We study a quantum-mechanical system, prepared, at t = 0, in a model state, that subsequently decays into a sea of other states whose energy levels form a discrete spectrum with given statistical properties. An important quantity is the survival probability P(t), defined as the probability, at time t, to find the system in the original model state. Our main purpose is to analyze the influence of the discreteness and statistical properties of the spectrum on the behavior of P(t). Since P(t) itself is a statistical quantity, we restrict our attention to its ensemble average , which is calculated analytically using random-matrix techniques, within certain approximations discussed in the text. We find, for , an exponential decay, followed by a revival, governed by the two-point structure of the statistical spectrum, thus giving a nonzero asymptotic value for large t's. The analytic result compares well with a number of computer simulations, over a time range discussed in the text. (author). 17 refs, 1 fig

Segmented-spectrum detection mechanism for medical x-ray in CdTe

Science.gov (United States)

Shi, Zaifeng; Meng, Qingzhen; Cao, Qingjie; Yao, Suying

2016-01-01

This paper presents a segmented X-ray spectrum detection method based on a layered X-ray detector in Cadmium Telluride (CdTe) substrate. We describe the three-dimensional structure of proposed detector pixel and investigate the matched spectrum-resolving method. Polychromatic X-ray beam enter the CdTe substrate edge on and will be absorbed completely in different thickness varying with photon energy. Discrete potential wells are formed under external controlling voltage to collect the photo-electrons generated in different layers, and segmented X-ray spectrum can be deduced from the quantity of photo-electrons. In this work, we verify the feasibility of the segmented-spectrum detection mechanism by simulating the absorption of monochromatic X-ray in a CdTe substrate. Experiments in simulation show that the number of photo-electrons grow exponentially with the increase of incident thickness, and photons with different energy will be absorbed in various thickness. The charges generated in different layers are collected into adjacent potential wells, and collection efficiency is estimated to be about 87% for different incident intensity under the 40000V/cm electric field. Errors caused by charge sharing between neighboring layers are also analyzed, and it can be considered negligible by setting appropriate size of electrodes.

On the influence of spatial discretization in LWR steady state and burnup calculations with HELIOS 1.9

International Nuclear Information System (INIS)

Merk, B.; Weiss, F. P.

2009-01-01

Cell and burnup calculations are fundamental to all deterministic static and transient 3D full core calculations for different operational states of the reactor. The spatial discretization used for the cell and burnup calculations influences significantly the results of full integral transport solutions. The influence of the discretization on k inf is shown for the steady state case and the influence on the neutron spectrum is analyzed. Moreover, the differences in k inf are presented for different spatial discretization strategies in the burnup calculation of Uranium Oxide (UOX) fuel. The resulting different flux distributions cause significant changes in the isotopic densities. The influence of the discretization strategies on the calculation of homogenized few group cross-sections is investigated. This detailed discretization study demonstrates the need for sufficiently fine discretization to produce reliable and accurate results when using integral transport methods. In contrast to the currently used discretization schemes, refined discretization is especially important in the moderator region of the unit cell to reproduce the influence on the thermal neutron spectrum. Additionally, the need for sufficient discretization affects the idea of full core calculations based on integral transport methods since it has to be discussed whether it is worth to do full core calculations with reduced discretization when facing this strong discretization effect. The computer resources required for full core calculations with fine discretization are currently not available. (authors)

The application of thermoluminescence dosimeter on the measurement of hard X-ray pulse energy spectrum

International Nuclear Information System (INIS)

Song Zhaohui; Wang Baohui; Wang Kuilu; Hei Dongwei; Sun Fengrong; Li Gang

2001-01-01

This paper introduce the application of thermoluminescence dosimeter (TLD) which composed by TLD-3500 Reader and TLD-100M chips on the measurement of hard X-ray pulse energy spectrum. The idea, using Filter Fluorescence Method (FFM) and TLD to measure hard X-ray pulse energy spectrum (from 10 keV to 100 keV), is discussed in details. Considering all the factors of the measuring surroundings, the measurement system of hard X-ray pulse has been devised. The calibration technique of absolute energy response of TLD is established. This method has been applied successfully on the radiation parameters measurement of the huge pulse radiation device -high-power pulser I. Hard X-ray pulse energy spectrum data of the pulser are acquired

Third-Order Density Perturbation and One-Loop Power Spectrum in Dark-Energy-Dominated Universe

OpenAIRE

Takahashi, Ryuichi

2008-01-01

We investigate the third-order density perturbation and the one-loop correction to the linear power spectrum in the dark-energy cosmological model. Our main interest is to understand the dark-energy effect on baryon acoustic oscillations in a quasi-nonlinear regime ($k \\approx 0.1h$/Mpc). Analytical solutions and simple fitting formulae are presented for the dark-energy model with the general time-varying equation of state $w(a)$. It turns out that the power spectrum coincides with the approx...

Minimum Energy Control of 2D Positive Continuous-Discrete Linear Systems

Directory of Open Access Journals (Sweden)

Kaczorek Tadeusz

2014-09-01

Full Text Available The minimum energy control problem for the 2D positive continuous-discrete linear systems is formulated and solved. Necessary and sufficient conditions for the reachability at the point of the systems are given. Sufficient conditions for the existence of solution to the problem are established. It is shown that if the system is reachable then there exists an optimal input that steers the state from zero boundary conditions to given final state and minimizing the performance index for only one step (q = 1. A procedure for solving of the problem is proposed and illustrated by a numerical example.

Photon energy spectrum in B →Xs + γ and comparison with data

International Nuclear Information System (INIS)

Ali, A.; Greub, C.

1995-06-01

A comparison of the inclusive photon energy spectrum in the radiative decay B→X s +γ; measured recently by the CLEO collaboration, with the standard model is presented, using a B-meson wave function model and improving earlier perturbative QCD-based computations of the same. The dependence of the photon energy spectrum on the non-perturbative model parameters, p F , the b-quark Fermi momentum in the B hadron, and m q , the spectator quark mass, is explicitly shown, allowing a comparison of these parameters with the ones obtained from the analysis of the lepton energy spectrum in semileptonic B decays. Taking into account present uncertainties, we estimate BR(B→X s +γ)=(2.55±1.28)x10 -4 in the standard model, assuming vertical stroke V ts vertical stroke /vertical stroke V cb vertical stroke =1.0. Comparing this with CLEO measurement BR(B→X s +γ)=(2.32±0.67)x10 -4 implies vertical stroke V ts vertical stroke /vertical stroke V cb vertical stroke =1.1±0.43, in agreement with the CKM unitarity. (orig.)

The 4p-subshell photoabsorption spectrum of singly ionized molybdenum

International Nuclear Information System (INIS)

Mansfield, M W D; Costello, J T; Kennedy, E T; Mosnier, J-P

2003-01-01

The 4p-subshell spectrum of Mo + has been recorded, for the first time, in the wavelength range 500-200 A. The spectrum is dominated by a 4p → 4d 'giant resonance' on which extensive discrete structure is superposed. With only one exception the discrete lines can be ordered into six Rydberg series, 4p 6 4d 56 S 5/2 → 4p 5 (4d 56 S)( 7 P)ns,nd (J = 3/2, 5/2, 7/2), converging on three limits, the Mo III levels 4p 5 (4d 56 S) 7 P 4,3,2 . The observed spectrum is analysed by comparison with both Hartree plus exchange with relativistic corrections and relativistic time-dependent local density approximation calculations. The evolution of the discrete structure line shapes interacting with the giant resonance is found to be in qualitative agreement with the theory of Connerade and Lane (1987 J. Phys. B: At. Mol. Phys. 20 L181-6)

On the spectral theory and dispersive estimates for a discrete Schroedinger equation in one dimension

International Nuclear Information System (INIS)

Pelinovsky, D. E.; Stefanov, A.

2008-01-01

Based on the recent work [Komech et al., 'Dispersive estimates for 1D discrete Schroedinger and Klein-Gordon equations', Appl. Anal. 85, 1487 (2006)] for compact potentials, we develop the spectral theory for the one-dimensional discrete Schroedinger operator, Hφ=(-Δ+V)φ=-(φ n+1 +φ n-1 -2φ n )+V n φ n . We show that under appropriate decay conditions on the general potential (and a nonresonance condition at the spectral edges), the spectrum of H consists of finitely many eigenvalues of finite multiplicities and the essential (absolutely continuous) spectrum, while the resolvent satisfies the limiting absorption principle and the Puiseux expansions near the edges. These properties imply the dispersive estimates parallel e itH P a.c. (H) parallel l σ 2 →l -σ 2 -3/2 for any fixed σ>(5/2) and any t>0, where P a.c. (H) denotes the spectral projection to the absolutely continuous spectrum of H. In addition, based on the scattering theory for the discrete Jost solutions and the previous results by Stefanov and Kevrekidis [''Asymptotic behaviour of small solutions for the discrete nonlinear Schroedinger and Klein-Gordon equations,'' Nonlinearity 18, 1841 (2005)], we find new dispersive estimates parallel e itH P a.c. (H) parallel l 1 →l ∞ -1/3 , which are sharp for the discrete Schroedinger operators even for V=0

Meshes optimized for discrete exterior calculus (DEC).

Energy Technology Data Exchange (ETDEWEB)

Mousley, Sarah C. [Univ. of Illinois, Urbana-Champaign, IL (United States); Deakin, Michael [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Knupp, Patrick [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Mitchell, Scott A. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

2017-12-01

We study the optimization of an energy function used by the meshing community to measure and improve mesh quality. This energy is non-traditional because it is dependent on both the primal triangulation and its dual Voronoi (power) diagram. The energy is a measure of the mesh's quality for usage in Discrete Exterior Calculus (DEC), a method for numerically solving PDEs. In DEC, the PDE domain is triangulated and this mesh is used to obtain discrete approximations of the continuous operators in the PDE. The energy of a mesh gives an upper bound on the error of the discrete diagonal approximation of the Hodge star operator. In practice, one begins with an initial mesh and then makes adjustments to produce a mesh of lower energy. However, we have discovered several shortcomings in directly optimizing this energy, e.g. its non-convexity, and we show that the search for an optimized mesh may lead to mesh inversion (malformed triangles). We propose a new energy function to address some of these issues.

Discretization of space and time: mass-energy relation, accelerating expansion of the Universe, Hubble constant

OpenAIRE

Roatta , Luca

2017-01-01

Assuming that space and time can only have discrete values, we obtain the expression of the gravitational potential energy that at large distance coincides with the Newtonian. In very precise circumstances it coincides with the relativistic mass-energy relation: this shows that the Universe is a black hole in which all bodies are subjected to an acceleration toward the border of the Universe itself. Since the Universe is a black hole with a fixed radius, we can obtain the density of the Unive...

Graph-cut based discrete-valued image reconstruction.

Science.gov (United States)

Tuysuzoglu, Ahmet; Karl, W Clem; Stojanovic, Ivana; Castañòn, David; Ünlü, M Selim

2015-05-01

Efficient graph-cut methods have been used with great success for labeling and denoising problems occurring in computer vision. Unfortunately, the presence of linear image mappings has prevented the use of these techniques in most discrete-amplitude image reconstruction problems. In this paper, we develop a graph-cut based framework for the direct solution of discrete amplitude linear image reconstruction problems cast as regularized energy function minimizations. We first analyze the structure of discrete linear inverse problem cost functions to show that the obstacle to the application of graph-cut methods to their solution is the variable mixing caused by the presence of the linear sensing operator. We then propose to use a surrogate energy functional that overcomes the challenges imposed by the sensing operator yet can be utilized efficiently in existing graph-cut frameworks. We use this surrogate energy functional to devise a monotonic iterative algorithm for the solution of discrete valued inverse problems. We first provide experiments using local convolutional operators and show the robustness of the proposed technique to noise and stability to changes in regularization parameter. Then we focus on nonlocal, tomographic examples where we consider limited-angle data problems. We compare our technique with state-of-the-art discrete and continuous image reconstruction techniques. Experiments show that the proposed method outperforms state-of-the-art techniques in challenging scenarios involving discrete valued unknowns.

An energy recondensation method using the discrete generalized multigroup energy expansion theory

International Nuclear Information System (INIS)

Zhu Lei; Forget, Benoit

2011-01-01

Highlights: → Discrete-generalized multigroup method was implemented as a recondensation scheme. → Coarse group cross-sections were recondensed from core-level solution. → Neighboring effect of reflector and MOX bundle was improved. → Methodology was shown to be fully consistent when a flat angular flux approximation is used. - Abstract: In this paper, the discrete generalized multigroup (DGM) method was used to recondense the coarse group cross-sections using the core level solution, thus providing a correction for neighboring effect found at the core level. This approach was tested using a discrete ordinates implementation in both 1-D and 2-D. Results indicate that 2 or 3 iterations can substantially improve the flux and fission density errors associated with strong interfacial spectral changes as found in the presence of strong absorbers, reflector of mixed-oxide fuel. The methodology is also proven to be fully consistent with the multigroup methodology as long as a flat-flux approximation is used spatially.

SLC energy spectrum monitor using synchrotron radiation

International Nuclear Information System (INIS)

Seeman, J.; Brunk, W.; Early, R.; Ross, M.; Tillmann, E.; Walz, D.

1986-01-01

The SLAC linac is being upgraded for the use in the SLAC Linear Collider (SLC). The improved linac must accelerate electron and positron bunches from 1.2 GeV to 50 GeV while producing output energy spectra of about 0.2%. The energy spectra must be maintained during operation to provide for good beam transmission and to minimize chromatic effects in the SLC ARCs and Final Focus. The energy spectra of these beams are determined by the bunch length and intensity, the RF phase and waveform and the intra-bunch longitudinal wakefields. A non-destructive energy spectrum monitor has been designed using a vertical wiggler magnet located downstream of the horizontal beam splitter at the end of the SLC linac. It produces synchrotron radiation which is viewed in an off-axis x-ray position sensitive detector. The expected resolution is 0.08 %. The design considerations of this monitor are presented. A pair of these monitors is under construction with an installation data set for late summer 1986

SLC energy spectrum monitor using synchrotron radiation

International Nuclear Information System (INIS)

Seeman, J.; Brunk, W.; Early, R.; Ross, M.; Tillmann, E.; Walz, D.

1986-04-01

The SLAC Linac is being upgraded for the use in the SLAC Linear Collider (SLC). The improved Linac must accelerate electron and positron bunches from 1.2 GeV to 50 GeV while producing output energy spectra of about 0.2%. The energy spectra must be maintained during operation to provide for good beam transmission and to minimize chromatic effects in the SLC ARCs and Final Focus. the energy spectra of these beams are determined by the bunch length and intensity, the RF phase and waveform and the intra-bunch longitudinal wakefields. A non-destructive energy spectrum monitor has been designed using a vertical wiggler magnet located downstream of the horizontal beam splitter at the end of the SLC Linac. It produces synchrotron radiation which is viewed in an off-axis x-ray position sensitive detector. The expected resolution is 0.08%. The design considerations of this monitor are presented in this paper. A pair of these monitors is under construction with an installation date set for late summer 1986. 5 refs., 6 figs

Improving behavioral realism in hybrid energy-economy models using discrete choice studies of personal transportation decisions

International Nuclear Information System (INIS)

Horne, M.; Jaccard, M.; Tiedemann, K.

2005-01-01

Hybrid energy-economy models combine top-down and bottom-up approaches to explore behaviorally realistic responses to technology-focused policies. This research uses empirically derived discrete choice models to inform key behavioral parameters in CIMS, a hybrid model. The discrete choice models are estimated for vehicle and commuting decisions from a survey of 1150 Canadians. With the choice models integrated into CIMS, we simulate carbon taxes, gasoline vehicle disincentives, and single occupancy vehicle disincentives to show how different policy levers can motivate technological change. We also use the empirical basis for the choice models to portray uncertainty in technological change, costs, and emissions. (author)

Discrete Energies of a Weakly Outcoupled Atom Laser Beam Outside the Bose–Einstein Condensate Region

Directory of Open Access Journals (Sweden)

Teguh Budi Prayitno

2014-12-01

Full Text Available We consider the possibility of a discrete set of energies of a weakly outcoupled atom laser beam to the homogeneous Schrödinger equation with anisotropic harmonic trap in Cartesian coordinates outside the Bose–Einstein condensate region. This treatment is used because working in the cylindrical coordinates is not really possible, even though we implement the cigar-shaped trap case. The Schrödinger equation appears to replace a set of two-coupled Gross– Pitaevskii equations by enabling the weak-coupling assumption. This atom laser can be produced in a simple way that only involves extracting the atoms in a condensate from by using the radio frequency field. We initially present the relation between condensates as sources and atom laser as an output by exploring the previous work of Riou et al. in the case of theoretical work for the propagation of atom laser beams. We also show that even though the discrete energies are obtained by means of an approaching harmonic oscillator, degeneracy is only available in two states because of the anisotropic external potential

Discrete Variational Approach for Modeling Laser-Plasma Interactions

Science.gov (United States)

Reyes, J. Paxon; Shadwick, B. A.

2014-10-01

The traditional approach for fluid models of laser-plasma interactions begins by approximating fields and derivatives on a grid in space and time, leading to difference equations that are manipulated to create a time-advance algorithm. In contrast, by introducing the spatial discretization at the level of the action, the resulting Euler-Lagrange equations have particular differencing approximations that will exactly satisfy discrete versions of the relevant conservation laws. For example, applying a spatial discretization in the Lagrangian density leads to continuous-time, discrete-space equations and exact energy conservation regardless of the spatial grid resolution. We compare the results of two discrete variational methods using the variational principles from Chen and Sudan and Brizard. Since the fluid system conserves energy and momentum, the relative errors in these conserved quantities are well-motivated physically as figures of merit for a particular method. This work was supported by the U. S. Department of Energy under Contract No. DE-SC0008382 and by the National Science Foundation under Contract No. PHY-1104683.

Accurate and efficient implementation of the von Neumann representation for laser pulses with discrete and finite spectra

International Nuclear Information System (INIS)

Dimler, Frank; Fechner, Susanne; Rodenberg, Alexander; Brixner, Tobias; Tannor, David J

2009-01-01

We recently introduced the von Neumann picture, a joint time-frequency representation, for describing ultrashort laser pulses. The method exploits a discrete phase-space lattice of nonorthogonal Gaussians to represent the pulses; an arbitrary pulse shape can be represented on this lattice in a one-to-one manner. Although the representation was originally defined for signals with an infinite continuous spectrum, it can be adapted to signals with discrete and finite spectrum with great computational savings, provided that discretization and truncation effects are handled with care. In this paper, we present three methods that avoid loss of accuracy due to these effects. The approach has immediate application to the representation and manipulation of femtosecond laser pulses produced by a liquid-crystal mask with a discrete and finite number of pixels.

A study of discrete nonlinear systems

International Nuclear Information System (INIS)

Dhillon, H.S.

2001-04-01

An investigation of various spatially discrete time-independent nonlinear models was undertaken. These models are generically applicable to many different physical systems including electron-phonon interactions in solids, magnetic multilayers, layered superconductors and classical lattice systems. To characterise the possible magnetic structures created on magnetic multilayers a model has been formulated and studied. The Euler-Lagrange equation for this model is a discrete version of the Sine-Gordon equation. Solutions of this equation are generated by applying the methods of Chaotic Dynamics - treating the space variable associated with the layer number as a discrete time variable. The states found indicate periodic, quasiperiodic and chaotic structures. Analytic solutions to the discrete nonlinear Schroedinger Equation (DNSE) with cubic nonlinearity are presented in the strong coupling limit. Using these as a starting point, a procedure is developed to determine the wave function and the energy eigenvalue for moderate coupling. The energy eigenvalues of the different structures of the wave function are found to be in excellent agreement with the exact strong coupling result. The solutions to the DNSE indicate commensurate and incommensurate spatial structures associated with different localisation patterns of the wave function. The states which arise may be fractal, periodic, quasiperiodic or chaotic. This work is then extended to solve a first order discrete nonlinear equation. The exact solutions for both the first and second order discrete nonlinear equations with cubic nonlinearity suggests that this method of studying discrete nonlinear equations may be applied to solve discrete equations with any order difference and cubic nonlinearity. (author)

Measurement of the energy spectrum of cosmic rays from the Pierre Auger Observatory

International Nuclear Information System (INIS)

Roth, M.

2009-01-01

The large sample of data collected by the Pierre Auger Observatory has led to a significant improvement over previous measurements on the energy spectrum of cosmic rays. We observe a suppression of the flux at the highest energy with a significance of more than 6 standard deviations. The spectral index γ of the flux, J∝E -γ , at energies between 4x10 18 eV and 4x10 19 eV is 2.69±0.02 (stat) ±0.06 (syst), steepening to 4.2±0.4 (stat) ±0.06 (syst) at higher energies, consistent with the prediction by Greisen and by Zatsepin and Kuz'min. Observations of cosmic rays by the fluorescence detector allowed the extension of the energy spectrum to lower energies, where the efficiency of the surface detector is less then 100% and a change in the spectral index is expected.

Effective lagrangian description on discrete gauge symmetries

International Nuclear Information System (INIS)

Banks, T.

1989-01-01

We exhibit a simple low-energy lagrangian which describes a system with a discrete remnant of a spontaneously broken continuous gauge symmetry. The lagrangian gives a simple description of the effects ascribed to such systems by Krauss and Wilczek: black holes carry discrete hair and interact with cosmic strings, and wormholes cannot lead to violation of discrete gauge symmetries. (orig.)

Explanation of the Knee-like Feature in the DAMPE Cosmic {e}^{-}+{e}^{+} Energy Spectrum

Science.gov (United States)

Fang, Kun; Bi, Xiao-Jun; Yin, Peng-Fei

2018-02-01

The DArk Matter Particle Explorer, a space-based high precision cosmic-ray detector, has just reported the new measurement of the total electron plus positron energy spectrum up to 4.6 TeV. A notable feature in the spectrum is the spectral break at ∼0.9 TeV, with the spectral index softening from ‑3.1 to ‑3.9. Such a feature is very similar to the knee at the cosmic nuclei energy spectrum. In this work, we propose that the knee-like feature can be explained naturally by assuming that the electrons are accelerated at the supernova remnants (SNRs) and released when the SNRs die out with lifetimes around 105 years. The cut-off energy of those electrons have already decreased to several TeV due to radiative cooling, which may induce the observed TeV spectral break. Another possibility is that the break is induced by a single nearby old SNR. Such a scenario may bring a large electron flux anisotropy that may be observable by the future detectors. We also show that a minor part of electrons escaping during the acceleration in young and nearby SNRs is able to contribute to a several TeV or higher energy region of the spectrum.

Determination of the Spectral Index in the Fission Spectrum Energy Regime

Energy Technology Data Exchange (ETDEWEB)

Lee, Amy Sarah [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2016-05-16

Neutron reaction cross sections play a vital role in tracking the production and destruction of isotopes exposed to neutron fluence. They are central to the process of reconciling the initial and final atom inventories. Measurements of irradiated samples by radiochemical methods in tangent with an algorithm are used to evaluate the fluence a sample is exposed to over the course of the irradiation. This algorithm is the Isotope Production Code (IPC) created and used by the radiochemistry data assessment team at Los Alamos National Laboratory (LANL). An integral result is calculated by varying the total neutron fluence seen by a sample. A sample, irradiated in a critical assembly, will be exposed to a unique neutron flux defined by the neutron source and distance of the sample from the source. Neutron cross sections utilized are a function of the hardness of the neutron spectrum at the location of irradiation. A spectral index is used an indicator of the hardness of the neutron spectrum. Cross sections fit forms applied in IPC are collapsed from a LANL 30-group energy structure. Several decades of research and development have been performed to formalize the current IPC cross section library. Basis of the current fission spectrum neutron reaction cross section library is rooted in critical assembly experiments performed from the 1950’s through the early 1970’s at LANL. The focus of this report is development of the spectral index used an indicator of the hardness of the neutron spectrum in the fission spectrum energy regime.

Possible dark energy imprints in the gravitational wave spectrum of mixed neutron-dark-energy stars

Energy Technology Data Exchange (ETDEWEB)

Yazadjiev, Stoytcho S. [Department of Theoretical Physics, Faculty of Physics, St. Kliment Ohridski University of Sofia, James Bourchier Blvd. 5, 1164 Sofia (Bulgaria); Doneva, Daniela D., E-mail: yazad@phys.uni-sofia.bg, E-mail: daniela.doneva@uni-tuebingen.de [Theoretical Astrophysics, IAAT, Eberhard-Karls University of Tübingen, Auf der Morgenstelle 10, 72076 Tübingen (Germany)

2012-03-01

In the present paper we study the oscillation spectrum of neutron stars containing both ordinary matter and dark energy in different proportions. Within the model we consider, the equilibrium configurations are numerically constructed and the results show that the properties of the mixed neuron-dark-energy star can differ significantly when the amount of dark energy in the stars is varied. The oscillations of the mixed neuron-dark-energy stars are studied in the Cowling approximation. As a result we find that the frequencies of the fundamental mode and the higher overtones are strongly affected by the dark energy content. This can be used in the future to detect the presence of dark energy in the neutron stars and to constrain the dark-energy models.

Direct measurement of the partial decay energy of 7Be inner bremstrahlung spectrum

International Nuclear Information System (INIS)

Sanjeeviah, H.; Sanjeeviah, B.

1978-01-01

The inner bremsstrahlung spectrum accompanying orbital electron capture decay of 7 Be to the first excited state of 7 Li was measured in coincidence with 477 keV gamma rays. From the Jauch plot of the spectrum the partial decay energy was found to be 394 +- 16 keV. The shape factor of the inner bremsstrahlung spectrum close to the end point was accurately determined. It was found to be a constant X(1.001 +- 0.002) (author)

The spectrum of axisymmetric torsional Alfven waves

International Nuclear Information System (INIS)

Sy, W.N.

1977-03-01

The spectrum of axisymmetric torsional Alfven waves propagating in a cylindrical, non-uniform, resistive plasma waveguide has been analysed by a method of singular perturbations. A simple condition has been derived which predicts whether the spectrum is continuous or discrete under given physical conditions. Application of this result to resolve an apparent discrepancy in experimental observations is briefly discussed. (Author)

Energy Optimal Tracking Control with Discrete Fluid Power Systems using Model Predictive Control

DEFF Research Database (Denmark)

Hansen, Anders Hedegaard; Asmussen, Magnus Færing; Bech, Michael Møller

2017-01-01

For Discrete Displacement Cylinder (DDC) drives the control task lies in choosing force level. Hence, which force level to apply and thereby which pressure level each cylinder chambers shall be connected to. The DDC system is inherently a force system why often a force reference is generated...... and compared to a PID like tracking controller combined with a FSA. The results indicate that the energy efficiency of position tracking DDC systems may be improved significantly by using the MPC algorithm....

ULF hydromagnetic oscillations with the discrete spectrum as eigenmodes of MHD-resonator in the near-Earth part of the plasma sheet

Directory of Open Access Journals (Sweden)

V. A. Mazur

2006-07-01

Full Text Available A new concept is proposed for the emergence of ULF geomagnetic oscillations with a discrete spectrum of frequencies (0.8, 1.3, 1.9, 2.6 ...mHz registered in the magnetosphere's midnight-morning sector. The concept relies on the assumption that these oscillations are MHD-resonator eigenmodes in the near-Earth plasma sheet. This magnetospheric area is where conditions are met for fast magnetosonic waves to be confined. The confinement is a result of the velocity values of fast magnetosonic waves in the near-Earth plasma sheet which differ greatly from those in the magnetotail lobes, leading to turning points forming in the tailward direction for the waves under study. To compute the eigenfrequency spectrum of such a resonator, we used a model magnetosphere with parabolic geometry. The fundamental harmonics of this resonator's eigenfrequencies are shown to be capable of being clustered into groups with average frequencies matching, with good accuracy, the frequencies of the observed oscillations. A possible explanation for the stability of the observed oscillation frequencies is that such a resonator might only form when the magnetosphere is in a certain unperturbed state.

ULF hydromagnetic oscillations with the discrete spectrum as eigenmodes of MHD-resonator in the near-Earth part of the plasma sheet

Directory of Open Access Journals (Sweden)

V. A. Mazur

2006-07-01

Full Text Available A new concept is proposed for the emergence of ULF geomagnetic oscillations with a discrete spectrum of frequencies (0.8, 1.3, 1.9, 2.6 ...mHz registered in the magnetosphere's midnight-morning sector. The concept relies on the assumption that these oscillations are MHD-resonator eigenmodes in the near-Earth plasma sheet. This magnetospheric area is where conditions are met for fast magnetosonic waves to be confined. The confinement is a result of the velocity values of fast magnetosonic waves in the near-Earth plasma sheet which differ greatly from those in the magnetotail lobes, leading to turning points forming in the tailward direction for the waves under study. To compute the eigenfrequency spectrum of such a resonator, we used a model magnetosphere with parabolic geometry. The fundamental harmonics of this resonator's eigenfrequencies are shown to be capable of being clustered into groups with average frequencies matching, with good accuracy, the frequencies of the observed oscillations. A possible explanation for the stability of the observed oscillation frequencies is that such a resonator might only form when the magnetosphere is in a certain unperturbed state.

An Energy-Efficient Game-Theory-Based Spectrum Decision Scheme for Cognitive Radio Sensor Networks.

Science.gov (United States)

Salim, Shelly; Moh, Sangman

2016-06-30

A cognitive radio sensor network (CRSN) is a wireless sensor network in which sensor nodes are equipped with cognitive radio. In this paper, we propose an energy-efficient game-theory-based spectrum decision (EGSD) scheme for CRSNs to prolong the network lifetime. Note that energy efficiency is the most important design consideration in CRSNs because it determines the network lifetime. The central part of the EGSD scheme consists of two spectrum selection algorithms: random selection and game-theory-based selection. The EGSD scheme also includes a clustering algorithm, spectrum characterization with a Markov chain, and cluster member coordination. Our performance study shows that EGSD outperforms the existing popular framework in terms of network lifetime and coordination overhead.

Measurement of Neutron Energy Spectrum Emitted by Cf-252 Source Using Time-of-Flight Method

Energy Technology Data Exchange (ETDEWEB)

Lee, Cheol Ho; Son, Jaebum; Kim, Tae Hoon; Lee, Sangmin; Kim, Yong-Kyun [Hanyang University, Seoul (Korea, Republic of)

2016-10-15

The techniques proposed to detect the neutrons usually require the detection of a secondary recoiling nucleus in a scintillator (or other type of detector) to indicate the rare collision of a neutron with a nucleus. This is the same basic technique, in this case detection of a recoil proton that was used by Chadwick in the 1930 s to discover and identify the neutron and determine its mass. It is primary technique still used today for detection of fast neutron, which typically involves the use of a hydrogen based organic plastic or liquid scintillator coupled to a photo-multiplier tube. The light output from such scintillators is a function of the cross section and nuclear kinematics of the n + nucleus collision. With the exception of deuterated scintillators, the scintillator signal does not necessarily produce a distinct peak in the scintillator spectrum directly related to the incident neutron energy. Instead neutron time-of-flight (TOF) often must be utilized to determine the neutron energy, which requires generation of a prompt start signal from the nuclear source emitting the neutrons. This method takes advantage of the high number of prompt gamma rays. The Time-of-Flight method was used to measure neutron energy spectrum emitted by the Cf-252 neutron source. Plastic scintillator that has a superior discrimination ability of neutron and gamma-ray was used as a stop signal detector and liquid scintillator was used as a stat signal detector. In experiment, neutron and gamma-ray spectrum was firstly measured and discriminated using the TOF method. Secondly, neutron energy spectrum was obtained through spectrum analysis. Equation of neutron energy spectrum that was emitted by Cf-252 source using the Gaussian fitting was obtained.

Discrete and mesoscopic regimes of finite-size wave turbulence

International Nuclear Information System (INIS)

L'vov, V. S.; Nazarenko, S.

2010-01-01

Bounding volume results in discreteness of eigenmodes in wave systems. This leads to a depletion or complete loss of wave resonances (three-wave, four-wave, etc.), which has a strong effect on wave turbulence (WT) i.e., on the statistical behavior of broadband sets of weakly nonlinear waves. This paper describes three different regimes of WT realizable for different levels of the wave excitations: discrete, mesoscopic and kinetic WT. Discrete WT comprises chaotic dynamics of interacting wave 'clusters' consisting of discrete (often finite) number of connected resonant wave triads (or quarters). Kinetic WT refers to the infinite-box theory, described by well-known wave-kinetic equations. Mesoscopic WT is a regime in which either the discrete and the kinetic evolutions alternate or when none of these two types is purely realized. We argue that in mesoscopic systems the wave spectrum experiences a sandpile behavior. Importantly, the mesoscopic regime is realized for a broad range of wave amplitudes which typically spans over several orders on magnitude, and not just for a particular intermediate level.

Discreteness of area in noncommutative space

Energy Technology Data Exchange (ETDEWEB)

Amelino-Camelia, Giovanni [Dipartimento di Fisica, Universita di Roma ' La Sapienza' and Sez. Roma1 INFN, P.le A. Moro 2, 00185 Roma (Italy)], E-mail: amelino@roma1.infn.it; Gubitosi, Giulia; Mercati, Flavio [Dipartimento di Fisica, Universita di Roma ' La Sapienza' and Sez. Roma1 INFN, P.le A. Moro 2, 00185 Roma (Italy)

2009-06-08

We introduce an area operator for the Moyal noncommutative plane. We find that the spectrum is discrete, but, contrary to the expectation formulated by other authors, not characterized by a 'minimum-area principle'. We show that an intuitive analysis of the uncertainty relations obtained from Moyal-plane noncommutativity is fully consistent with our results for the spectrum, and we argue that our area operator should be generalizable to several other noncommutative spaces. We also observe that the properties of distances and areas in the Moyal plane expose some weaknesses in the line of reasoning adopted in some of the heuristic analyses of the measurability of geometric spacetime observables in the quantum-gravity realm.

Discreteness of area in noncommutative space

International Nuclear Information System (INIS)

Amelino-Camelia, Giovanni; Gubitosi, Giulia; Mercati, Flavio

2009-01-01

We introduce an area operator for the Moyal noncommutative plane. We find that the spectrum is discrete, but, contrary to the expectation formulated by other authors, not characterized by a 'minimum-area principle'. We show that an intuitive analysis of the uncertainty relations obtained from Moyal-plane noncommutativity is fully consistent with our results for the spectrum, and we argue that our area operator should be generalizable to several other noncommutative spaces. We also observe that the properties of distances and areas in the Moyal plane expose some weaknesses in the line of reasoning adopted in some of the heuristic analyses of the measurability of geometric spacetime observables in the quantum-gravity realm.

Continuous energy Neutron Transport Monte Carlo Simulator Project: Decomposition of the neutron energy spectrum by target nuclei tagging

Energy Technology Data Exchange (ETDEWEB)

Barcellos, Luiz Felipe F.C.; Bodmann, Bardo E.J.; Vilhena, Marco T.M.B., E-mail: luizfelipe.fcb@gmail.com, E-mail: bardo.bodmann@ufrgs.br, E-mail: mtmbvilhena@gmail.com [Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS (Brazil). Grupo de Estudos Nucleares; Leite, Sergio Q. Bogado, E-mail: sbogado@ibest.com.br [Comissao Nacional de Energia Nuclear (CNEN), Rio de Janeiro, RJ (Brazil)

2017-07-01

In this work a Monte Carlo simulator with continuous energy is used. This simulator distinguishes itself by using the sum of three probability distributions to represent the neutron spectrum. Two distributions have known shape, but have varying population of neutrons in time, and these are the fission neutron spectrum (for high energy neutrons) and the Maxwell-Boltzmann distribution (for thermal neutrons). The third distribution has an a priori unknown and possibly variable shape with time and is determined from parametrizations of Monte Carlo simulation. It is common practice in neutron transport calculations, e.g. multi-group transport, to consider that the neutrons only lose energy with each scattering reaction and then to use a thermal group with a Maxwellian distribution. Such an approximation is valid due to the fact that for fast neutrons up-scattering occurrence is irrelevant, being only appreciable at low energies, i.e. in the thermal energy region, in which it can be regarded as a Maxwell-Boltzmann distribution for thermal equilibrium. In this work the possible neutron-matter interactions are simulated with exception of the up-scattering of neutrons. In order to preserve the thermal spectrum, neutrons are selected stochastically as being part of the thermal population and have an energy attributed to them taken from a Maxwellian distribution. It is then shown how this procedure can emulate the up-scattering effect by the increase in the neutron population kinetic energy. Since the simulator uses tags to identify the reactions it is possible not only to plot the distributions by neutron energy, but also by the type of interaction with matter and with the identification of the target nuclei involved in the process. This work contains some preliminary results obtained from a Monte Carlo simulator for neutron transport that is being developed at Federal University of Rio Grande do Sul. (author)

Integrable lattices and their sublattices: From the discrete Moutard (discrete Cauchy-Riemann) 4-point equation to the self-adjoint 5-point scheme

International Nuclear Information System (INIS)

Doliwa, A.; Grinevich, P.; Nieszporski, M.; Santini, P. M.

2007-01-01

We present the sublattice approach, a procedure to generate, from a given integrable lattice, a sublattice which inherits its integrability features. We consider, as illustrative example of this approach, the discrete Moutard 4-point equation and its sublattice, the self-adjoint 5-point scheme on the star of the square lattice, which are relevant in the theory of the integrable discrete geometries and in the theory of discrete holomorphic and harmonic functions (in this last context, the discrete Moutard equation is called discrete Cauchy-Riemann equation). Therefore an integrable, at one energy, discretization of elliptic two-dimensional operators is considered. We use the sublattice point of view to derive, from the Darboux transformations and superposition formulas of the discrete Moutard equation, the Darboux transformations and superposition formulas of the self-adjoint 5-point scheme. We also construct, from algebro-geometric solutions of the discrete Moutard equation, algebro-geometric solutions of the self-adjoint 5-point scheme. In particular, we show that the corresponding restrictions on the finite-gap data are of the same type as those for the fixed energy problem for the two-dimensional Schroedinger operator. We finally use these solutions to construct explicit examples of discrete holomorphic and harmonic functions, as well as examples of quadrilateral surfaces in R 3

Research on pyrolysis behavior of Camellia sinensis branches via the Discrete Distributed Activation Energy Model.

Science.gov (United States)

Zhou, Bingliang; Zhou, Jianbin; Zhang, Qisheng

2017-10-01

This study aims at investigating the pyrolysis behavior of Camellia sinensis branches by the Discrete Distributed Activation Energy Model (DAEM) and thermogravimetric experiments. Then the Discrete DAEM method is used to describe pyrolysis process of Camellia sinensis branches dominated by 12 characterized reactions. The decomposition mechanism of Camellia sinensis branches and interaction with components are observed. And the reaction at 350.77°C is a significant boundary of the first and second reaction range. The pyrolysis process of Camellia sinensis branches at the heating rate of 10,000°C/min is predicted and provides valuable references for gasification or combustion. The relationship and function between four typical indexes and heating rates from 10 to 10,000°C/min are revealed. Copyright © 2017 Elsevier Ltd. All rights reserved.

Discrete structures in F-theory compactifications

Energy Technology Data Exchange (ETDEWEB)

Till, Oskar

2016-05-04

In this thesis we study global properties of F-theory compactifications on elliptically and genus-one fibered Calabi-Yau varieties. This is motivated by phenomenological considerations as well as by the need for a deeper understanding of the set of consistent F-theory vacua. The global geometric features arise from discrete and arithmetic structures in the torus fiber and can be studied in detail for fibrations over generic bases. In the case of elliptic fibrations we study the role of the torsion subgroup of the Mordell-Weil group of sections in four dimensional compactifications. We show how the existence of a torsional section restricts the admissible matter representations in the theory. This is shown to be equivalent to inducing a non-trivial fundamental group of the gauge group. Compactifying F-theory on genus-one fibrations with multisections gives rise to discrete selection rules. In field theory the discrete symmetry is a broken U(1) symmetry. In the geometry the higgsing corresponds to a conifold transition. We explain in detail the origin of the discrete symmetry from two different M-theory phases and put the result into the context of torsion homology. Finally we systematically construct consistent gauge fluxes on genus-one fibrations and show that these induce an anomaly free chiral spectrum.

Compatible Spatial Discretizations for Partial Differential Equations

Energy Technology Data Exchange (ETDEWEB)

Arnold, Douglas, N, ed.

2004-11-25

From May 11--15, 2004, the Institute for Mathematics and its Applications held a hot topics workshop on Compatible Spatial Discretizations for Partial Differential Equations. The numerical solution of partial differential equations (PDE) is a fundamental task in science and engineering. The goal of the workshop was to bring together a spectrum of scientists at the forefront of the research in the numerical solution of PDEs to discuss compatible spatial discretizations. We define compatible spatial discretizations as those that inherit or mimic fundamental properties of the PDE such as topology, conservation, symmetries, and positivity structures and maximum principles. A wide variety of discretization methods applied across a wide range of scientific and engineering applications have been designed to or found to inherit or mimic intrinsic spatial structure and reproduce fundamental properties of the solution of the continuous PDE model at the finite dimensional level. A profusion of such methods and concepts relevant to understanding them have been developed and explored: mixed finite element methods, mimetic finite differences, support operator methods, control volume methods, discrete differential forms, Whitney forms, conservative differencing, discrete Hodge operators, discrete Helmholtz decomposition, finite integration techniques, staggered grid and dual grid methods, etc. This workshop seeks to foster communication among the diverse groups of researchers designing, applying, and studying such methods as well as researchers involved in practical solution of large scale problems that may benefit from advancements in such discretizations; to help elucidate the relations between the different methods and concepts; and to generally advance our understanding in the area of compatible spatial discretization methods for PDE. Particular points of emphasis included: + Identification of intrinsic properties of PDE models that are critical for the fidelity of numerical

Calculation of the energy spectrum of atmospheric gamma-rays between 1 and 1000 MeV

International Nuclear Information System (INIS)

Martin, I.M.; Dutra, S.L.G.; Palmeira, R.A.R.

The energy spectrum of atmospheric gamma-rays at 4 g/cm 2 has been calculated for cut-off rigidities of 4.5, 10 and 16 GV. The considered processes for the production of these gamma-rays were the π 0 decay plus the bremsstrahlung from primary, secondary like splash and re-entrant albedo electrons. The calculations indicated that the spectrum could be fitted to a power law in energy, with the exponential index varying from 1.1 in the energy range 1 - 10 MeV, to 1.4 in the energy range 10 - 200 MeV and 1.8 in the energy range 200 - 1000 MeV. These results are discussed [pt

An Energy-Efficient Game-Theory-Based Spectrum Decision Scheme for Cognitive Radio Sensor Networks

Directory of Open Access Journals (Sweden)

Shelly Salim

2016-06-01

Full Text Available A cognitive radio sensor network (CRSN is a wireless sensor network in which sensor nodes are equipped with cognitive radio. In this paper, we propose an energy-efficient game-theory-based spectrum decision (EGSD scheme for CRSNs to prolong the network lifetime. Note that energy efficiency is the most important design consideration in CRSNs because it determines the network lifetime. The central part of the EGSD scheme consists of two spectrum selection algorithms: random selection and game-theory-based selection. The EGSD scheme also includes a clustering algorithm, spectrum characterization with a Markov chain, and cluster member coordination. Our performance study shows that EGSD outperforms the existing popular framework in terms of network lifetime and coordination overhead.

Measurement of the transverse energy spectrum in proton-nucleon collisions

International Nuclear Information System (INIS)

Bettoni, D.

1988-01-01

The author describes a measurement of the transverse energy spectrum in proton-nucleon interactions carried out at the CERN SPS using the HELIOS spectrometer. The measurement is of particular interest in that it is performed in a rapidity region away from central rapidity, where experimental data is scarce. In this rapidity region very interesting physics is anticipated and the measurement of the proton-nucleon collisions is essential as a basis to understand the more complicated proton-nucleus and nucleus-nucleus interactions. Both these topics are part of the experimental program of HELIOS. The measurement was done using a deuterium target enclosed in an iron tube. The contribution to the transverse energy spectrum from the p-Fe events is discriminated against by reconstructing the primary interaction vertex using drift chamber information. The measured spectrum is corrected via Monte Carlo to deconvolute the effect of reinteractions. High spatial resolution and multi-track resolving power are achieved with the use of a cool gas, such that the electron characteristic energy is close to the thermal limit: this implies a small diffusion coefficient and a consequently good positional accuracy. Of vital importance are the low value of the drift velocity, the fast, differentiating electronics and a careful shaping of the electric field configuration to improve the isochrony of the drift collection. The author reports on the design and tests of drift chamber prototypes built along the above lines, with which a spatial accuracy of 0.06 mm and a double track resolution of 0.6 mm were measured. He also describes the final drift chamber system and its operation in HELIOS

Geometry and Hamiltonian mechanics on discrete spaces

International Nuclear Information System (INIS)

Talasila, V; Clemente-Gallardo, J; Schaft, A J van der

2004-01-01

Numerical simulation is often crucial for analysing the behaviour of many complex systems which do not admit analytic solutions. To this end, one either converts a 'smooth' model into a discrete (in space and time) model, or models systems directly at a discrete level. The goal of this paper is to provide a discrete analogue of differential geometry, and to define on these discrete models a formal discrete Hamiltonian structure-in doing so we try to bring together various fundamental concepts from numerical analysis, differential geometry, algebraic geometry, simplicial homology and classical Hamiltonian mechanics. For example, the concept of a twisted derivation is borrowed from algebraic geometry for developing a discrete calculus. The theory is applied to a nonlinear pendulum and we compare the dynamics obtained through a discrete modelling approach with the dynamics obtained via the usual discretization procedures. Also an example of an energy-conserving algorithm on a simple harmonic oscillator is presented, and its effect on the Poisson structure is discussed

The discrete null space method for the energy-consistent integration of constrained mechanical systems. Part III: Flexible multibody dynamics

International Nuclear Information System (INIS)

Leyendecker, Sigrid; Betsch, Peter; Steinmann, Paul

2008-01-01

In the present work, the unified framework for the computational treatment of rigid bodies and nonlinear beams developed by Betsch and Steinmann (Multibody Syst. Dyn. 8, 367-391, 2002) is extended to the realm of nonlinear shells. In particular, a specific constrained formulation of shells is proposed which leads to the semi-discrete equations of motion characterized by a set of differential-algebraic equations (DAEs). The DAEs provide a uniform description for rigid bodies, semi-discrete beams and shells and, consequently, flexible multibody systems. The constraints may be divided into two classes: (i) internal constraints which are intimately connected with the assumption of rigidity of the bodies, and (ii) external constraints related to the presence of joints in a multibody framework. The present approach thus circumvents the use of rotational variables throughout the whole time discretization, facilitating the design of energy-momentum methods for flexible multibody dynamics. After the discretization has been completed a size-reduction of the discrete system is performed by eliminating the constraint forces. Numerical examples dealing with a spatial slider-crank mechanism and with intersecting shells illustrate the performance of the proposed method

Quantum models with energy-dependent potentials solvable in terms of exceptional orthogonal polynomials

International Nuclear Information System (INIS)

Schulze-Halberg, Axel; Roy, Pinaki

2017-01-01

We construct energy-dependent potentials for which the Schrödinger equations admit solutions in terms of exceptional orthogonal polynomials. Our method of construction is based on certain point transformations, applied to the equations of exceptional Hermite, Jacobi and Laguerre polynomials. We present several examples of boundary-value problems with energy-dependent potentials that admit a discrete spectrum and the corresponding normalizable solutions in closed form.

Quantum models with energy-dependent potentials solvable in terms of exceptional orthogonal polynomials

Energy Technology Data Exchange (ETDEWEB)

Schulze-Halberg, Axel, E-mail: axgeschu@iun.edu [Department of Mathematics and Actuarial Science, Indiana University Northwest, 3400 Broadway, Gary IN 46408 (United States); Department of Physics, Indiana University Northwest, 3400 Broadway, Gary IN 46408 (United States); Roy, Pinaki, E-mail: pinaki@isical.ac.in [Physics and Applied Mathematics Unit, Indian Statistical Institute, Kolkata 700108 (India)

2017-03-15

We construct energy-dependent potentials for which the Schrödinger equations admit solutions in terms of exceptional orthogonal polynomials. Our method of construction is based on certain point transformations, applied to the equations of exceptional Hermite, Jacobi and Laguerre polynomials. We present several examples of boundary-value problems with energy-dependent potentials that admit a discrete spectrum and the corresponding normalizable solutions in closed form.

3D spectrum imaging of multi-wall carbon nanotube coupled π-surface modes utilising electron energy-loss spectra acquired using a STEM/Enfina system

International Nuclear Information System (INIS)

Seepujak, A.; Bangert, U.; Gutierrez-Sosa, A.; Harvey, A.J.; Blank, V.D.; Kulnitskiy, B.A.; Batov, D.V.

2005-01-01

Numerous studies have utilised electron energy-loss (EEL) spectra acquired in the plasmon (2-10 eV) regime in order to probe delocalised π-electronic states of multi-wall carbon nanotubes (MWCNTs). Interpretation of electron energy loss (EEL) spectra of MWCNTs in the 2-10 eV regime. Carbon (accepted for publication); Blank et al. J. Appl. Phys. 91 (2002) 1657). In the present contribution, EEL spectra were acquired from a 2D raster defined on a bottle-shaped MWCNT, using a Gatan UHV Enfina system attached to a dedicated scanning transmission electron microscope (STEM). The technique utilised to isolate and sequentially filter each of the volume and surface resonances is described in detail. Utilising a scale for the intensity of a filtered mode enables one to 'see' the distribution of each resonance in the raster. This enables striking 3D resonance-filtered spectrum images (SIs) of π-collective modes to be observed. Red-shift of the lower energy split π-surface resonance provides explicit evidence of π-surface mode coupling predicted for thin graphitic films (Lucas et al. Phys. Rev. B 49 (1994) 2888). Resonance-filtered SIs are also compared to non-filtered SIs with suppressed surface contributions, acquired utilising a displaced collector aperture. The present filtering technique is seen to isolate surface contributions more effectively, and without the significant loss of statistics, associated with the displaced collector aperture mode. Isolation of collective modes utilising 3D resonance-filtered spectrum imaging, demonstrates a valuable method for 'pinpointing' the location of discrete modes in irregularly shaped nanostructures

Energy efficient cross layer design for spectrum sharing systems

KAUST Repository

Alabbasi, Abdulrahman

2016-10-06

We propose a cross layer design that optimizes the energy efficiency of spectrum sharing systems. The energy per good bit (EPG) is considered as an energy efficiency metric. We optimize the secondary user\\'s transmission power and media access frame length to minimize the EPG metric. We protect the primary user transmission via an outage probability constraint. The non-convex targeted problem is optimized by utilizing the generalized convexity theory and verifying the strictly pseudo-convex structure of the problem. Analytical results of the optimal power and frame length are derived. We also used these results in proposing an algorithm, which guarantees the existence of a global optimal solution. Selected numerical results show the improvement of the proposed system compared to other systems. © 2016 IEEE.

Effects of fault heterogeneity on seismic energy and spectrum

Science.gov (United States)

Dragoni, Michele; Santini, Stefano

2017-12-01

We study the effects of friction heterogeneity on the dynamics of a seismogenic fault. To this aim, we consider a fault model containing two asperities with different static frictions and a rate-dependent dynamic friction. We consider the seismic events produced by the consecutive failure of the two asperities and study their properties as functions of the ratio between static frictions. In particular, we calculate the moment rate, the stress evolution during fault slip, the average stress drop, the partitioning of energy release, the seismic energy, the far-field waveforms and the spectrum of seismic waves. These quantities depend to various extent on the friction distribution on the fault. In particular, the stress distribution on the fault is always strongly heterogeneous at the beginning of the seismic event. Seismic energy and frictional heat decrease with increasing friction heterogeneity, while seismic efficiency is constant. We obtain an equation relating seismic efficiency to the parameters of the friction law, showing that the efficiency is maximum for smaller values of dynamic friction. The seismic spectrum depends on the friction distribution as to the positions and the values of the minima. However, under the model assumption that the slip durations are the same for both asperities, the corner frequency is independent of the friction distribution, but it depends on the friction law and on the coupling between asperities. The model provides a relation between the total radiated energy and the seismic moment that is consistent with the empirical relation between the two quantities. The fault model with one asperity is also considered as a particular case. The model is applied to the 1965 Rat Islands (Alaska) earthquake and shows the role of fault heterogeneity in controlling the spatial distribution of stress drop as well as the time dependence and the final amount of radiated energy.

Discrete stochastic analogs of Erlang epidemic models.

Science.gov (United States)

Getz, Wayne M; Dougherty, Eric R

2018-12-01

Erlang differential equation models of epidemic processes provide more realistic disease-class transition dynamics from susceptible (S) to exposed (E) to infectious (I) and removed (R) categories than the ubiquitous SEIR model. The latter is itself is at one end of the spectrum of Erlang SE[Formula: see text]I[Formula: see text]R models with [Formula: see text] concatenated E compartments and [Formula: see text] concatenated I compartments. Discrete-time models, however, are computationally much simpler to simulate and fit to epidemic outbreak data than continuous-time differential equations, and are also much more readily extended to include demographic and other types of stochasticity. Here we formulate discrete-time deterministic analogs of the Erlang models, and their stochastic extension, based on a time-to-go distributional principle. Depending on which distributions are used (e.g. discretized Erlang, Gamma, Beta, or Uniform distributions), we demonstrate that our formulation represents both a discretization of Erlang epidemic models and generalizations thereof. We consider the challenges of fitting SE[Formula: see text]I[Formula: see text]R models and our discrete-time analog to data (the recent outbreak of Ebola in Liberia). We demonstrate that the latter performs much better than the former; although confining fits to strict SEIR formulations reduces the numerical challenges, but sacrifices best-fit likelihood scores by at least 7%.

The energy-momentum spectrum in local field theories with broken Lorentz-symmetry

International Nuclear Information System (INIS)

Borchers, H.J.; Buchholz, D.

1984-05-01

Assuming locality of the observables and positivity of the energy it is shown that the joint spectrum of the energy-momentum operators has a Lorentz-invariant lower boundary in all superselection sectors. This result is of interest if the Lorentz-symmetry is (spontaneously) broken, such as in the charged sectors of quantum electrodynamics. (orig.)

Discrete gradient methods for solving variational image regularisation models

International Nuclear Information System (INIS)

Grimm, V; McLachlan, Robert I; McLaren, David I; Quispel, G R W; Schönlieb, C-B

2017-01-01

Discrete gradient methods are well-known methods of geometric numerical integration, which preserve the dissipation of gradient systems. In this paper we show that this property of discrete gradient methods can be interesting in the context of variational models for image processing, that is where the processed image is computed as a minimiser of an energy functional. Numerical schemes for computing minimisers of such energies are desired to inherit the dissipative property of the gradient system associated to the energy and consequently guarantee a monotonic decrease of the energy along iterations, avoiding situations in which more computational work might lead to less optimal solutions. Under appropriate smoothness assumptions on the energy functional we prove that discrete gradient methods guarantee a monotonic decrease of the energy towards stationary states, and we promote their use in image processing by exhibiting experiments with convex and non-convex variational models for image deblurring, denoising, and inpainting. (paper)

An absolute measurement of 252Cf prompt fission neutron spectrum at low energy range

International Nuclear Information System (INIS)

Lajtai, A.; Dyachenko, P.P.; Kutzaeva, L.S.; Kononov, V.N.; Androsenko, P.A.; Androsenko, A.A.

1983-01-01

Prompt neutron energy spectrum at low energies (25 keV 252 Cf spontaneous fission has been measured with a time-of-flight technique on a 30 cm flight-path. Ionization chamber and lithium-glass were used as fission fragment and neutron detectors, respectively. Lithium glasses of NE-912 (containing 6 Li) and of NE-913 (containing 7 Li) 45 mm in diameter and 9.5 mm in thickness have been employed alternatively, for the registration of fission neutrons and gammas. For the correct determination of the multiscattering effects - the main difficulty of the low energy neutron spectrum measurements - a special geometry for the neutron detector was used. Special attention was paid also to the determination of the absolute efficiency of the neutron detector. The real response function of the spectrometer was determined by a Monte-Carlo calculation. The scattering material content of the ionization chamber containing a 252 Cf source was minimized. As a result of this measurement a prompt fission neutron spectrum of Maxwell type with a T=1.42 MeV parameter was obtained at this low energy range. We did not find any neutron excess or irregularities over the Maxwellian. (author)

Properties of Energy Spectra of Molecular Crystals Investigated by Nonlinear Theory

Science.gov (United States)

Pang, Xiao-Feng; Zhang, Huai-Wu

We calculate the quantum energy spectra of molecular crystals, such as acetanilide, by using discrete nonlinear Schrodinger equation, containing various interactions, appropriate to the systems. The energy spectra consist of many energy bands, in each energy band there are a lot of energy levels including some higher excited states. The result of energy spectrum is basically consistent with experimental values obtained by infrared absorption and Raman scattering in acetanilide and can also explain some experimental results obtained by Careri et al. Finally, we further discuss the influences of variously characteristic parameters on the energy spectra of the systems.

Nonlinear single-spin spectrum analyzer.

Science.gov (United States)

Kotler, Shlomi; Akerman, Nitzan; Glickman, Yinnon; Ozeri, Roee

2013-03-15

Qubits have been used as linear spectrum analyzers of their environments. Here we solve the problem of nonlinear spectral analysis, required for discrete noise induced by a strongly coupled environment. Our nonperturbative analytical model shows a nonlinear signal dependence on noise power, resulting in a spectral resolution beyond the Fourier limit as well as frequency mixing. We develop a noise characterization scheme adapted to this nonlinearity. We then apply it using a single trapped ion as a sensitive probe of strong, non-Gaussian, discrete magnetic field noise. Finally, we experimentally compared the performance of equidistant vs Uhrig modulation schemes for spectral analysis.

The puzzle of the ankle in the Ultrahigh Energy Cosmic Ray Spectrum, and composition indicators

Science.gov (United States)

Farrar, Glennys

2015-08-01

The sharp change in slope of the ultra-high energy cosmic ray spectrum around 10^18.6 eV (the ankle), combined with evidence of a light but extragalactic component near and below the ankle and intermediate composition above, has proved exceedingly challenging to understand theoretically. In this talk I discuss two possible solutions to the puzzle and how they can be (in)validated.First, I present a new mechanism whereby photo-disintegration of ultra-high energy nuclei in the region surrounding a UHECR accelerator naturally accounts for the observed spectrum and inferred composition (using LHC-tuned models extrapolated to UHE) at Earth. We discuss the conditions required to reproduce the spectrum above 10^17.5 eV and the composition, which -- in our model -- consists below the ankle of extragalactic protons and the high energy tail of Galactic Cosmic Rays, and above the ankle of surviving nuclei from the extended source. Predictions for the spectrum and flavors of neutrinos resulting from this process will be presented, and also implications for candidate sources.The other possible explanation is that in actuality UHECRs are entirely or almost entirely protons, and the cross-section for p-Air scattering increases more rapidly above center-of-mass energy of 70 TeV (10 times the current LHC cm energy) than predicted in conventional models. This gives an equally good fit to the depth-of-shower maximum behavior obverved by Auger, while being an intriguing sign of new state in QCD at extremely high energy density.

Thermostatistic properties of a q-deformed ideal Fermi gas with a general energy spectrum

International Nuclear Information System (INIS)

Cai, Shukuan; Su, Guozhen; Chen, Jincan

2007-01-01

The thermostatistic problems of a q-deformed ideal Fermi gas in any dimensional space and with a general energy spectrum are studied, based on the q-deformed Fermi-Dirac distribution. The effects of the deformation parameter q on the properties of the system are revealed. It is shown that q-deformation results in some novel characteristics different from those of an ordinary system. Besides, it is found that the effects of the q-deformation on the properties of the Fermi systems are very different for different dimensional spaces and different energy spectrums

Extended defect related energy loss in CVD diamond revealed by spectrum imaging in a dedicated STEM

International Nuclear Information System (INIS)

Bangert, U.; Harvey, A.J.; Schreck, M.; Hoermann, F.

2005-01-01

This article aims at investigations of the low EEL region in the wide band gap system diamond. The advent of the UHV Enfina electron energy loss spectrometer combined with Digital Micrograph acquisition and processing software has made reliable detection of absorption losses below 10 eV possible. Incorporated into a dedicated STEM this instrumentation allows the acquisition of spectral information via spectrum maps (spectrum imaging) of sample areas hundreds of nanometers across, with nanometers pixel sizes, adequate spectrum statistics and 0.3 eV energy resolution, in direct correlation with microstructural features in the mapping area. We aim at discerning defect related losses at band gap energies, and discuss different routes to simultaneously process and analyse the spectra in a map. This involves extracting the zero loss peak from each spectrum and constructing ratio maps from the intensities in two energy windows, one defect related and one at a higher, crystal bandstructure dominated energy. This was applied to the residual spectrum maps and their first derivatives. Secondly, guided by theoretical EEL spectra calculations, the low loss spectra were fitted by a series of gaussian distributions. Pixel maps were constructed from amplitude ratios of gaussians, situated in the defect and the unaffected energy regime. The results demonstrate the existence of sp 2 -bonded carbon in the vicinity of stacking faults and partial dislocations in CVD diamond as well as additional states below conduction band, tailing deep into the band gap, at a node in a perfect dislocation. Calculated EEL spectra of shuffle dislocations give similar absorption features at 5-8 eV, and it is thought that this common feature is due to sp 2 -type bonding

Quasicanonical structure of optimal control in constrained discrete systems

Science.gov (United States)

Sieniutycz, S.

2003-06-01

This paper considers discrete processes governed by difference rather than differential equations for the state transformation. The basic question asked is if and when Hamiltonian canonical structures are possible in optimal discrete systems. Considering constrained discrete control, general optimization algorithms are derived that constitute suitable theoretical and computational tools when evaluating extremum properties of constrained physical models. The mathematical basis of the general theory is the Bellman method of dynamic programming (DP) and its extension in the form of the so-called Carathéodory-Boltyanski (CB) stage criterion which allows a variation of the terminal state that is otherwise fixed in the Bellman's method. Two relatively unknown, powerful optimization algorithms are obtained: an unconventional discrete formalism of optimization based on a Hamiltonian for multistage systems with unconstrained intervals of holdup time, and the time interval constrained extension of the formalism. These results are general; namely, one arrives at: the discrete canonical Hamilton equations, maximum principles, and (at the continuous limit of processes with free intervals of time) the classical Hamilton-Jacobi theory along with all basic results of variational calculus. Vast spectrum of applications of the theory is briefly discussed.

The high energy x-ray spectrum of the Crab Nebula observed from OSO 8

International Nuclear Information System (INIS)

Dolan, J.F.; Crannell, L.J.; Dennis, B.R.; Orwig, L.E.; Maurer, G.S.

1977-01-01

The X-ray spectrum of the Crab Nebula was measured with the scintillation spectrometer on board the OSO-8 satellite. The total emission of the X-ray source shows no long term variability. The spectrum itself can be described by a single power law out to energies of at least 500 keV

Origin of the ankle in the ultrahigh energy cosmic ray spectrum, and of the extragalactic protons below it

Science.gov (United States)

Unger, Michael; Farrar, Glennys R.; Anchordoqui, Luis A.

2015-12-01

The sharp change in slope of the ultrahigh energy cosmic ray (UHECR) spectrum around 1 018.6 eV (the ankle), combined with evidence of a light but extragalactic component near and below the ankle and intermediate composition above, has proved exceedingly challenging to understand theoretically, without fine-tuning. We propose a mechanism whereby photo-disintegration of ultrahigh energy nuclei in the region surrounding a UHECR accelerator accounts for the observed spectrum and inferred composition at Earth. For suitable source conditions, the model reproduces the spectrum and the composition over the entire extragalactic cosmic ray energy range, i.e. above 1 017.5 eV . Predictions for the spectrum and flavors of neutrinos resulting from this process are also presented.

Direct measurement of the energy spectrum of an intense proton beam

International Nuclear Information System (INIS)

Leeper, R.J.; Lee, J.R.; Kissel, L.; Johnson, D.J.; Stygar, W.A.; Hebron, D.E.; Roose, L.D.

1983-01-01

A time-resolved magnetic spectrometer has been used to measure the energy spectrum of an intense (0.5 TW/cm 2 ) proton beam. A thin (2400 A) gold foil placed at the focus of an ion diode Rutherford scattered protons by 90 0 into the spectrometer, reducing the beam intensity to a level suitable for magnetic analysis. The scattered beam was collimated by two 1 mm diameter apertures separated by 12.3 cm. The collimated protons were deflected in a 12.7 cm diameter, 6.65 Kg samarium-cobalt permanent magnet. The deflected protons were recorded simultaneously on CR-39 and eight 1 mm 2 by 35 μm thick PIN diodes. A Monte Carlo computer code was used to calculate the sensitivity and resolution of the spectrometer. Data taken on Proto-I show a 150 keV to 250 keV wide proton energy spectrum at each instant in time

The vacuum profile of the energy spectrum compressor

International Nuclear Information System (INIS)

Kuijsten, W.J.

1988-12-01

A finite element model has been made of the vacuum system of the Energy Spectrum Compressor. It gives the possibility to calculate the average pressure profile of the system in a fast way. It is required that the average pressure in the system does not influence the present performance of the linac nor the performance of the beam switch yard. Calculations show that with standard pumps of 60 l/s an average pressure of -5 Pa can be obtained. 7 refs.; 8 figs.; 2 tabs

Method to deduce the energy spectrum by the Pierre Auger Observatory

Energy Technology Data Exchange (ETDEWEB)

Maris, I.; Roth, M.; Schmidt, T.; Schuessler, F.; Unger, M. [Univ. Karlsruhe (Germany); Bluemer, J. [Univ. Karlsruhe (Germany); Forschungszentrum Karlsruhe (Germany)

2007-07-01

Taken into account the great advantage of having a hybrid detector it has been developed a method, simulation independent, to determine the energy of the comic rays recorded by the surface detector of the Pierre Auger Observatory. The method assumes that the cosmic ray flux has the same distribution in zenith angle for all energy ranges. Therefore one can relate the calorimetric measurement of the fluorescence detector of the CR energy with a SD quantity, e.g. shower size at 1000m distance from the core, corrected for the different attenuations in the atmosphere. The method of measuring and calibrating the primary energy and the influence of reconstruction uncertainties on the energy spectrum are presented. (orig.)

The low-energy spectrum of (2, 0) theory on T5 x R

International Nuclear Information System (INIS)

Henningson, Maans

2008-01-01

We consider the ADE-series of (2, 0) supersymmetric quantum theories on T 5 x R, where the first factor is a flat spatial five-torus, and the second factor denotes time. The quantum states of such a theory Φ are characterized by a discrete quantum number f element of H 3 (T 5 , C), where the finite abelian group C is the center subgroup of the corresponding simply connected simply laced Lie group G. At energies that are low compared to the inverse size of the T 5 , the spectrum consists of a set of continua of states, each of which is characterized by the value of f and some number 5r of additional continuous parameters. By exploiting the interpretation of this theory as the ultraviolet completion of maximally supersymmetric Yang-Mills theory on T 4 x S 1 x R with gauge group G adj = G/C and coupling constant g given by the square root of the radius of the S 1 factor, one may compute the number N f r (Φ) of such continua. We perform these calculations in detail for the A- and D-series. While the Yang-Mills theory formalism is manifestly invariant under the SL 4 (Z) mapping class group of T 4 , the results are actually found to be invariant under the SL 5 (Z) mapping class group of T 5 , which provides a strong consistency check.

Impact of dissipation on the energy spectrum of experimental turbulence of gravity surface waves

Science.gov (United States)

Campagne, Antoine; Hassaini, Roumaissa; Redor, Ivan; Sommeria, Joël; Valran, Thomas; Viboud, Samuel; Mordant, Nicolas

2018-04-01

We discuss the impact of dissipation on the development of the energy spectrum in wave turbulence of gravity surface waves with emphasis on the effect of surface contamination. We performed experiments in the Coriolis facility, which is a 13-m-diam wave tank. We took care of cleaning surface contamination as well as possible, considering that the surface of water exceeds 100 m2. We observe that for the cleanest condition the frequency energy spectrum shows a power-law decay extending up to the gravity capillary crossover (14 Hz) with a spectral exponent that is increasing with the forcing strength and decaying with surface contamination. Although slightly higher than reported previously in the literature, the exponent for the cleanest water remains significantly below the prediction from the weak turbulence theory. By discussing length and time scales, we show that weak turbulence cannot be expected at frequencies above 3 Hz. We observe with a stereoscopic reconstruction technique that the increase with the forcing strength of energy spectrum beyond 3 Hz is mostly due to the formation and strengthening of bound waves.

Reducing pressure oscillations in discrete fluid power systems

DEFF Research Database (Denmark)

Hansen, Anders Hedegaard; Pedersen, Henrik Clemmensen

2016-01-01

Discrete fluid power systems featuring transmission lines inherently include pressure oscillations. Experimental verification of a discrete fluid power power take off system for wave energy converters has shown the cylinder pressure to oscillate as force shifts are performed. This article investi...... investigates how cylinder pressure oscillations may be reduced by shaping the valve opening trajectory without the need for closed loop pressure feedback. Furthermore the energy costs of reducing pressure oscillations are investigated....

Discrete mKdV and discrete sine-Gordon flows on discrete space curves

International Nuclear Information System (INIS)

Inoguchi, Jun-ichi; Kajiwara, Kenji; Matsuura, Nozomu; Ohta, Yasuhiro

2014-01-01

In this paper, we consider the discrete deformation of the discrete space curves with constant torsion described by the discrete mKdV or the discrete sine-Gordon equations, and show that it is formulated as the torsion-preserving equidistant deformation on the osculating plane which satisfies the isoperimetric condition. The curve is reconstructed from the deformation data by using the Sym–Tafel formula. The isoperimetric equidistant deformation of the space curves does not preserve the torsion in general. However, it is possible to construct the torsion-preserving deformation by tuning the deformation parameters. Further, it is also possible to make an arbitrary choice of the deformation described by the discrete mKdV equation or by the discrete sine-Gordon equation at each step. We finally show that the discrete deformation of discrete space curves yields the discrete K-surfaces. (paper)

Intermediate neutron spectrum problems and the intermediate neutron spectrum experiment

International Nuclear Information System (INIS)

Jaegers, P.J.; Sanchez, R.G.

1996-01-01

Criticality benchmark data for intermediate energy spectrum systems does not exist. These systems are dominated by scattering and fission events induced by neutrons with energies between 1 eV and 1 MeV. Nuclear data uncertainties have been reported for such systems which can not be resolved without benchmark critical experiments. Intermediate energy spectrum systems have been proposed for the geological disposition of surplus fissile materials. Without the proper benchmarking of the nuclear data in the intermediate energy spectrum, adequate criticality safety margins can not be guaranteed. The Zeus critical experiment now under construction will provide this necessary benchmark data

Measurement of the very-forward energy spectrum in pp collisions at √(s) = 13 TeV with CMS

Energy Technology Data Exchange (ETDEWEB)

Baur, Sebastian; Akbiyik, Melike; Baus, Colin; Katkov, Igor; Ulrich, Ralf; Woehrmann, Hauke [Karlsruher Institut fuer Technologie (Germany)

2016-07-01

The energy spectrum dN/dE in pp collisions at a centre-of-mass energy of √(s)=13 TeV is measured with the CASTOR calorimeter of CMS at pseudorapidities -5.2>η>-6.6. The spectrum of the total energy, as well as the hadronic and electromagnetic energy, is presented and compared to models used to describe high-energy hadronic interactions. The performance also of model used to describe ultra-high energy cosmic ray air showers is tested, and the possible impact of the measurement on the air shower development is illustrated.

Discrete Curvatures and Discrete Minimal Surfaces

KAUST Repository

Sun, Xiang

2012-06-01

This thesis presents an overview of some approaches to compute Gaussian and mean curvature on discrete surfaces and discusses discrete minimal surfaces. The variety of applications of differential geometry in visualization and shape design leads to great interest in studying discrete surfaces. With the rich smooth surface theory in hand, one would hope that this elegant theory can still be applied to the discrete counter part. Such a generalization, however, is not always successful. While discrete surfaces have the advantage of being finite dimensional, thus easier to treat, their geometric properties such as curvatures are not well defined in the classical sense. Furthermore, the powerful calculus tool can hardly be applied. The methods in this thesis, including angular defect formula, cotangent formula, parallel meshes, relative geometry etc. are approaches based on offset meshes or generalized offset meshes. As an important application, we discuss discrete minimal surfaces and discrete Koenigs meshes.

Physical models on discrete space and time

International Nuclear Information System (INIS)

Lorente, M.

1986-01-01

The idea of space and time quantum operators with a discrete spectrum has been proposed frequently since the discovery that some physical quantities exhibit measured values that are multiples of fundamental units. This paper first reviews a number of these physical models. They are: the method of finite elements proposed by Bender et al; the quantum field theory model on discrete space-time proposed by Yamamoto; the finite dimensional quantum mechanics approach proposed by Santhanam et al; the idea of space-time as lattices of n-simplices proposed by Kaplunovsky et al; and the theory of elementary processes proposed by Weizsaecker and his colleagues. The paper then presents a model proposed by the authors and based on the (n+1)-dimensional space-time lattice where fundamental entities interact among themselves 1 to 2n in order to build up a n-dimensional cubic lattice as a ground field where the physical interactions take place. The space-time coordinates are nothing more than the labelling of the ground field and take only discrete values. 11 references

Discrete breathers in graphane: Effect of temperature

Energy Technology Data Exchange (ETDEWEB)

Baimova, J. A., E-mail: julia.a.baimova@gmail.com [Russian Academy of Sciences, Institute of Metal Physics, Ural Branch (Russian Federation); Murzaev, R. T.; Lobzenko, I. P.; Dmitriev, S. V. [Russian Academy of Sciences, Institute for Metals Superplasticity Problems (Russian Federation); Zhou, Kun [Nanyang Technological University, School of Mechanical and Aerospace Engineering (Singapore)

2016-05-15

The discrete breathers in graphane in thermodynamic equilibrium in the temperature range 50–600 K are studied by molecular dynamics simulation. A discrete breather is a hydrogen atom vibrating along the normal to a sheet of graphane at a high amplitude. As was found earlier, the lifetime of a discrete breather at zero temperature corresponds to several tens of thousands of vibrations. The effect of temperature on the decay time of discrete breathers and the probability of their detachment from a sheet of graphane are studied in this work. It is shown that closely spaced breathers can exchange energy with each other at zero temperature. The data obtained suggest that thermally activated discrete breathers can be involved in the dehydrogenation of graphane, which is important for hydrogen energetics.

Evaluation of a new neutron energy spectrum unfolding code based on an Adaptive Neuro-Fuzzy Inference System (ANFIS).

Science.gov (United States)

Hosseini, Seyed Abolfazl; Esmaili Paeen Afrakoti, Iman

2018-01-17

The purpose of the present study was to reconstruct the energy spectrum of a poly-energetic neutron source using an algorithm developed based on an Adaptive Neuro-Fuzzy Inference System (ANFIS). ANFIS is a kind of artificial neural network based on the Takagi-Sugeno fuzzy inference system. The ANFIS algorithm uses the advantages of both fuzzy inference systems and artificial neural networks to improve the effectiveness of algorithms in various applications such as modeling, control and classification. The neutron pulse height distributions used as input data in the training procedure for the ANFIS algorithm were obtained from the simulations performed by MCNPX-ESUT computational code (MCNPX-Energy engineering of Sharif University of Technology). Taking into account the normalization condition of each energy spectrum, 4300 neutron energy spectra were generated randomly. (The value in each bin was generated randomly, and finally a normalization of each generated energy spectrum was performed). The randomly generated neutron energy spectra were considered as output data of the developed ANFIS computational code in the training step. To calculate the neutron energy spectrum using conventional methods, an inverse problem with an approximately singular response matrix (with the determinant of the matrix close to zero) should be solved. The solution of the inverse problem using the conventional methods unfold neutron energy spectrum with low accuracy. Application of the iterative algorithms in the solution of such a problem, or utilizing the intelligent algorithms (in which there is no need to solve the problem), is usually preferred for unfolding of the energy spectrum. Therefore, the main reason for development of intelligent algorithms like ANFIS for unfolding of neutron energy spectra is to avoid solving the inverse problem. In the present study, the unfolded neutron energy spectra of 252Cf and 241Am-9Be neutron sources using the developed computational code were

On the high energy gamma ray spectrum and the particle production model

International Nuclear Information System (INIS)

Ohta, Itaru; Tezuka, Ikuo.

1979-01-01

A small emulsion chamber, 25 cm x 20 cm in area and 12 radiation lengths in thick, was exposed with JAL jet-cargo at an atmospheric depth of 260 g/cm 2 during 150 hrs. The gamma ray spectrum derived by combining data from X-ray films and nuclear emulsions is well represented by I sub(r) (>=Er) = (3.65 +- 0.30) x 10 -8 [E sub(r)/TeV]sup(-1.89+0.06-0.09)/cm 2 sr sec in the energy range 200 - 3,000 GeV. This result is in good agreement with those of several other groups. We discuss our data in terms of Feynman's and Koba-Nielsen-Olesen's scaling law of high energy particle production model. Interpreted in terms of an assumption of mild violation of the scaling law as x.d delta-s / delta-s indx = AE sup(2a)exp (-BE sup(a)x), our gamma ray spectrum results suggest an existence of a violation parameter of a = 0.18, which is consistent with results from gamma ray spectrum observations at great depth such as the mountain elevations. (author)

THE γ-RAY SPECTRUM OF GEMINGA AND THE INVERSE COMPTON MODEL OF PULSAR HIGH-ENERGY EMISSION

International Nuclear Information System (INIS)

Lyutikov, Maxim

2012-01-01

We reanalyze the Fermi spectra of the Geminga and Vela pulsars. We find that the spectrum of Geminga above the break is well approximated by a simple power law without the exponential cutoff, making Geminga's spectrum similar to that of Crab. Vela's broadband γ-ray spectrum is equally well fit with both the exponential cutoff and the double power-law shapes. In the broadband double power-law fits, for a typical Fermi spectrum of a bright γ-ray pulsar, most of the errors accumulate due to the arbitrary parameterization of the spectral roll-off. In addition, a power law with an exponential cutoff gives an acceptable fit for the underlying double power-law spectrum for a very broad range of parameters, making such fitting procedures insensitive to the underlying Fermi photon spectrum. Our results have important implications for the mechanism of pulsar high-energy emission. A number of observed properties of γ-ray pulsars—i.e., the broken power-law spectra without exponential cutoffs and stretching in the case of Crab beyond the maximal curvature limit, spectral breaks close to or exceeding the maximal breaks due to curvature emission, patterns of the relative intensities of the leading and trailing pulses in the Crab repeated in the X-ray and γ-ray regions, presence of profile peaks at lower energies aligned with γ-ray peaks—all point to the inverse Compton origin of the high-energy emission from majority of pulsars.

Energy detection based on undecimated discrete wavelet transform and its application in magnetic anomaly detection.

Directory of Open Access Journals (Sweden)

Xinhua Nie

Full Text Available Magnetic anomaly detection (MAD is a passive approach for detection of a ferromagnetic target, and its performance is often limited by external noises. In consideration of one major noise source is the fractal noise (or called 1/f noise with a power spectral density of 1/fa (0energy detection method based on undecimated discrete wavelet transform (UDWT is proposed in this paper. Firstly, the foundations of magnetic anomaly detection and UDWT are introduced in brief, while a possible detection system based on giant magneto-impedance (GMI magnetic sensor is also given out. Then our proposed energy detection based on UDWT is described in detail, and the probabilities of false alarm and detection for given the detection threshold in theory are presented. It is noticeable that no a priori assumptions regarding the ferromagnetic target or the magnetic noise probability are necessary for our method, and different from the discrete wavelet transform (DWT, the UDWT is shift invariant. Finally, some simulations are performed and the results show that the detection performance of our proposed detector is better than that of the conventional energy detector even utilized in the Gaussian white noise, especially when the spectral parameter α is less than 1.0. In addition, a real-world experiment was done to demonstrate the advantages of the proposed method.

Quasi-energy of ultracold neutrons

International Nuclear Information System (INIS)

Frank, A.I.; Nosov, V.G.

1992-01-01

A solution is found to the problem of the propagation of a neutron beam transmitted through a periodically acting high-speed chopper. It is a generalization of the Moshinsky's problem of the evolution of a plane wave in the right half-space after an ideal absorber at the origin of coordinates has been instantaneously removed. The energy spectrum of transmitted neutrons is found to be discrete and corresponding to their quasi-energy. Interference of the states corresponding to different satellite lines leads to a complex spatial pattern with typical beats. A number of experiments with ultracold neutrons are suggested and discussed. 12 refs.; 1 fig

An optimized surface plasmon photovoltaic structure using energy transfer between discrete nano-particles.

Science.gov (United States)

Lin, Albert; Fu, Sze-Ming; Chung, Yen-Kai; Lai, Shih-Yun; Tseng, Chi-Wei

2013-01-14

Surface plasmon enhancement has been proposed as a way to achieve higher absorption for thin-film photovoltaics, where surface plasmon polariton(SPP) and localized surface plasmon (LSP) are shown to provide dense near field and far field light scattering. Here it is shown that controlled far-field light scattering can be achieved using successive coupling between surface plasmonic (SP) nano-particles. Through genetic algorithm (GA) optimization, energy transfer between discrete nano-particles (ETDNP) is identified, which enhances solar cell efficiency. The optimized energy transfer structure acts like lumped-element transmission line and can properly alter the direction of photon flow. Increased in-plane component of wavevector is thus achieved and photon path length is extended. In addition, Wood-Rayleigh anomaly, at which transmission minimum occurs, is avoided through GA optimization. Optimized energy transfer structure provides 46.95% improvement over baseline planar cell. It achieves larger angular scattering capability compared to conventional surface plasmon polariton back reflector structure and index-guided structure due to SP energy transfer through mode coupling. Via SP mediated energy transfer, an alternative way to control the light flow inside thin-film is proposed, which can be more efficient than conventional index-guided mode using total internal reflection (TIR).

Sputtering calculations with the discrete ordinated method

International Nuclear Information System (INIS)

Hoffman, T.J.; Dodds, H.L. Jr.; Robinson, M.T.; Holmes, D.K.

1977-01-01

The purpose of this work is to investigate the applicability of the discrete ordinates (S/sub N/) method to light ion sputtering problems. In particular, the neutral particle discrete ordinates computer code, ANISN, was used to calculate sputtering yields. No modifications to this code were necessary to treat charged particle transport. However, a cross section processing code was written for the generation of multigroup cross sections; these cross sections include a modification to the total macroscopic cross section to account for electronic interactions and small-scattering-angle elastic interactions. The discrete ordinates approach enables calculation of the sputtering yield as functions of incident energy and angle and of many related quantities such as ion reflection coefficients, angular and energy distributions of sputtering particles, the behavior of beams penetrating thin foils, etc. The results of several sputtering problems as calculated with ANISN are presented

Advantages of Real-Time Spectrum Analyzers in High-Energy Physics Applications

International Nuclear Information System (INIS)

Parker, Louis

2004-01-01

Typically, particles are injected into the ring at low energy levels and then 'ramped up' to higher levels. During ramping, it is important that the horizontal and vertical tune frequencies do not shift, lest they hit upon a resonant combination that causes beam instability or sudden total loss of ring beam current (beam blow up). Beam instabilities can be caused by a number of factors. Non-linearities and/or different response times of independent controls such as beam position monitor (BPM) cables and circuits, magnets for guidance and focusing of the beam, Klystrons or Tetrodes (which provide power to RF cavities that transmit energy to the beam), and vacuum pumps and monitors can all cause beam instabilities. Vibrations and lack of proper shielding are other factors. The challenge for operators and researchers is to correctly identify the factors causing beam instabilities and blow up so that costly accelerator time is not interrupted and experimental results are not compromised. The instrument often used to identify problems in particle accelerator applications is the spectrum analyzer. This paper will discuss the advantages of real time spectrum analyzers (RSA) versus swept frequency spectrum analyzers in HEP applications. The main focus will be on monitoring beam position and stability, especially during ramp-up. Also covered will be use of RSA for chromaticity measurements, Phase Locked Loop (PLL) diagnostics, and vibration analysis

Third-Order Density Perturbation and One-Loop Power Spectrum in Dark-Energy-Dominated Universe(Astrophysics and Cosmology)

OpenAIRE

Ryuichi, TAKAHASHI; Department of Physics and Astrophysics, Nagoya University

2008-01-01

We investigate the third-order density perturbation and the one-loop correction to the linear power spectrum in the dark-energy cosmological model. Our main interest is to understand the dark-energy effect on baryon acoustic oscillations in a quasi-nonlinear regime (k≈0.1h/Mpc). Analytical solutions and simple fitting formulae are presented for the dark-energy model with the general time-varying equation of state w(a). It turns out that the power spectrum coincides with the approximate res...

Neutron fluence rate and energy spectrum in SPRR-300 reactor thermal column

International Nuclear Information System (INIS)

Dou Haifeng; Dai Junlong

2006-01-01

In order to modify the simple one-dimension model, the neutron fluence rate distribution calculated with ANISN code ws checked with that calculated with MCNP code. To modify the error caused by ignoring the neutron landscape orientation leaking, the reflector that can't be modeled in a simple one-dimension model was dealt by extending landscape orientation scale. On this condition the neutron fluence rate distribution and the energy spectrum in the thermal column of SPRR-300 reactor were calculated with one-dimensional code ANISN, and the results of Cd ratio are well accorded with the experimental results. The deviation between them is less than 5% and it isn't above 10% in one or two special positions. It indicates that neutron fluence rate distribution and energy spectrum in the thermal column can be well calculated with one-dimensional code ANISN. (authors)

Reconstruction of the neutron spectrum using an artificial neural network in CPU and GPU

International Nuclear Information System (INIS)

Hernandez D, V. M.; Moreno M, A.; Ortiz L, M. A.; Vega C, H. R.; Alonso M, O. E.

2016-10-01

The increase in computing power in personal computers has been increasing, computers now have several processors in the CPU and in addition multiple CUDA cores in the graphics processing unit (GPU); both systems can be used individually or combined to perform scientific computation without resorting to processor or supercomputing arrangements. The Bonner sphere spectrometer is the most commonly used multi-element system for neutron detection purposes and its associated spectrum. Each sphere-detector combination gives a particular response that depends on the energy of the neutrons, and the total set of these responses is known like the responses matrix Rφ(E). Thus, the counting rates obtained with each sphere and the neutron spectrum is related to the Fredholm equation in its discrete version. For the reconstruction of the spectrum has a system of poorly conditioned equations with an infinite number of solutions and to find the appropriate solution, it has been proposed the use of artificial intelligence through neural networks with different platforms CPU and GPU. (Author)

The energy spectrum of 662 keV photons in a water equivalent phantom

International Nuclear Information System (INIS)

Akar Tarim, U.; Gurler, O.; Ozmutlu, E.N.; Yalcin, S.; Gundogdu, O.; Sharaf, J.M.; Bradley, D.A.

2012-01-01

Investigation is made on the energy spectrum of photons originating from interactions of 662 keV primary gamma-ray photons emitted by a point source positioned at the centre of a water equivalent solid phantom of dimensions 19 cm×19 cm×24 cm. Peaks resulting from total energy loss (photopeak) and multiple and back scattering have been observed using a 51 mm×51 mm NaI(Tl) detector; good agreement being found between the measured and simulated response functions. The energy spectrum of the gamma photons obtained through the Monte Carlo simulation reveals local maxima at about 100 keV and 210 keV, being also observed in the experimental response function. Such spectra can be used as a method of testing the water equivalence of solid phantom media before their use for dosimetry measurements. - Highlights: ► Peaks resulting from total energy loss (photopeak) and multiple and back scattering were observed. ► Energy distribution of γ-ray photons from a point source at the centre of a water equivalent solid phantom. ► The method can be applied to various detector geometries.

The su(2)α Hahn oscillator and a discrete Fourier-Hahn transform

International Nuclear Information System (INIS)

Jafarov, E I; Stoilova, N I; Van der Jeugt, J

2011-01-01

We define the quadratic algebra su(2) α which is a one-parameter deformation of the Lie algebra su(2) extended by a parity operator. The odd-dimensional representations of su(2) (with representation label j, a positive integer) can be extended to representations of su(2) α . We investigate a model of the finite one-dimensional harmonic oscillator based upon this algebra su(2) α . It turns out that in this model the spectrum of the position and momentum operator can be computed explicitly, and that the corresponding (discrete) wavefunctions can be determined in terms of Hahn polynomials. The operation mapping position wavefunctions into momentum wavefunctions is studied, and this so-called discrete Fourier-Hahn transform is computed explicitly. The matrix of this discrete Fourier-Hahn transform has many interesting properties, similar to those of the traditional discrete Fourier transform. (paper)

A response matrix method for slab-geometry discrete ordinates adjoint calculations in energy-dependent source-detector problems

Energy Technology Data Exchange (ETDEWEB)

Mansur, Ralph S.; Moura, Carlos A., E-mail: ralph@ime.uerj.br, E-mail: demoura@ime.uerj.br [Universidade do Estado do Rio de Janeiro (UERJ), RJ (Brazil). Departamento de Engenharia Mecanica; Barros, Ricardo C., E-mail: rcbarros@pq.cnpq.br [Universidade do Estado do Rio de Janeiro (UERJ), Nova Friburgo, RJ (Brazil). Departamento de Modelagem Computacional

2017-07-01

Presented here is an application of the Response Matrix (RM) method for adjoint discrete ordinates (S{sub N}) problems in slab geometry applied to energy-dependent source-detector problems. The adjoint RM method is free from spatial truncation errors, as it generates numerical results for the adjoint angular fluxes in multilayer slabs that agree with the numerical values obtained from the analytical solution of the energy multigroup adjoint SN equations. Numerical results are given for two typical source-detector problems to illustrate the accuracy and the efficiency of the offered RM computer code. (author)

Ion energy spectrum just after the application of current pulse for turbulent heating in the TRIAM-1 tokamak

Energy Technology Data Exchange (ETDEWEB)

Nakamura, K; Nakamura, Y; Hiraki, N; Itoh, S [Kyushu Univ., Fukuoka (Japan). Research Inst. for Applied Mechanics

1981-07-01

Temporal evolution and spatial profile of ion energy spectrum just after the application of current pulse for turbulent heating are investigated experimentally in TRIAM-1 and numerically with a Fokker-Planck equation. Two-component ion energy spectrum formed by turbulent heating relaxes to single one within tau sub(i) (ion collision time).

Ion energy spectrum just after the application of current pulse for turbulent heating in the TRIAM-1 tokamak

International Nuclear Information System (INIS)

Nakamura, Kazuo; Nakamura, Yukio; Hiraki, Naoji; Itoh, Satoshi

1981-01-01

Temporal evolution and spatial profile of ion energy spectrum just after the application of current pulse for turbulent heating are investigated experimentally in TRIAM-1 and numerically with a Fokker-Planck equation. Two-component ion energy spectrum formed by turbulent heating relaxes to single one within tau sub(i) (ion collision time). (author)

Energy-density spectrum of the vacuum around a cosmic string

International Nuclear Information System (INIS)

Sarmiento, A.; Hacyan, S.

1988-01-01

The explicit form of the spectrum of the energy density of the vacuum surrounding a cosmic string as would be seen by an observer at rest is calculated. Spin-0, -half, or -1 massless fields are considered and it is found that the result is independent of the spin value. An interpretation which differs from the one usually found in the literature is also given

Single-wave-number representation of nonlinear energy spectrum in elastic-wave turbulence of the Föppl-von Kármán equation: energy decomposition analysis and energy budget.

Science.gov (United States)

Yokoyama, Naoto; Takaoka, Masanori

2014-12-01

A single-wave-number representation of a nonlinear energy spectrum, i.e., a stretching-energy spectrum, is found in elastic-wave turbulence governed by the Föppl-von Kármán (FvK) equation. The representation enables energy decomposition analysis in the wave-number space and analytical expressions of detailed energy budgets in the nonlinear interactions. We numerically solved the FvK equation and observed the following facts. Kinetic energy and bending energy are comparable with each other at large wave numbers as the weak turbulence theory suggests. On the other hand, stretching energy is larger than the bending energy at small wave numbers, i.e., the nonlinearity is relatively strong. The strong correlation between a mode a(k) and its companion mode a(-k) is observed at the small wave numbers. The energy is input into the wave field through stretching-energy transfer at the small wave numbers, and dissipated through the quartic part of kinetic-energy transfer at the large wave numbers. Total-energy flux consistent with energy conservation is calculated directly by using the analytical expression of the total-energy transfer, and the forward energy cascade is observed clearly.

Spectrum and energy levels of Y VI

International Nuclear Information System (INIS)

Persson, W.; Reader, J.

1986-01-01

The spectrum of the five-times-ionized yttrium atom (Y VI), excited in a sliding-spark discharge, was studied in the 160--2500 A-circle range. About 900 Y VI lines were classified as transitions between 101 odd and 69 even energy levels.The energy-level system established includes almost all levels of the 4s 2 4p 4 , 4s4p 5 , 4s 2 4p 3 4d, 5d, 5s, 6s, and 5p configurations and a number of levels of the 7s, 4f, and 4s4p 4 4d configurations. The observed level system has been theoretically interpreted by means of Hartree--Fock calculations and least-squares parametric fits. Strong configuration mixings are found between the 4s4p 5 and 4s 2 4p 3 4d configurations, between the 4s 2 4p 3 5p and 4s4p 4 4d configurations, and between the 4s 2 4p 3 4f and 4s4p 4 4d configurations. From the optimized energy-level values, a system of Ritz-type wavelength standards with accuracies varying from 0.0003 to 0.003 A-circle in the range 179--500 A-circle has been determined. The ionization energy as determined from 4s 2 4p 3 ns levels (n = 5-7) is 737 110 +- 200 cm/sup -1/ (91.390 +- 0.025 eV)

Prediction of background in low-energy spectrum of phoswich detector

International Nuclear Information System (INIS)

Arun, B.; Manohari, M.; Mathiyarasu, R.; Rajagopal, V.; Jose, M.T.

2014-01-01

In vivo monitoring of actinides in occupational workers is done using Phoswich detector by measuring the low-energy X ray and gamma rays. Quantification of actinides like plutonium and americium in the lungs is extremely difficult due to higher background in the low-energy regions, which is from ambient background as well as from the subject. In the latter case, it is mainly due to the Compton scattering of body potassium, which varies person-to-person. Hence, an accurate prediction of subject-specific background counts in the lower-energy regions is an essential element in the in vivo measurement of plutonium and americium. Empirical equations are established for the prediction of background count rate in 239 Pu and 241 Am lower-energy regions, called 'target regions', as a function of count rate in the monitoring region (97-130 keV)/ 40 K region in the high-energy spectrum, weight-to-height ratio of the subject (scattering parameter) and the gender. (authors)

All-particle cosmic ray energy spectrum measured by the HAWC experiment from 10 to 500 TeV

Science.gov (United States)

Alfaro, R.; Alvarez, C.; Álvarez, J. D.; Arceo, R.; Arteaga-Velázquez, J. C.; Avila Rojas, D.; Ayala Solares, H. A.; Barber, A. S.; Becerril, A.; Belmont-Moreno, E.; BenZvi, S. Y.; Brisbois, C.; Caballero-Mora, K. S.; Capistrán, T.; Carramiñana, A.; Casanova, S.; Castillo, M.; Cotti, U.; Cotzomi, J.; Coutiño de León, S.; De León, C.; De la Fuente, E.; Diaz Hernandez, R.; Dichiara, S.; Dingus, B. L.; DuVernois, M. A.; Díaz-Vélez, J. C.; Ellsworth, R. W.; Enriquez-Rivera, O.; Fiorino, D. W.; Fleischhack, H.; Fraija, N.; García-González, J. A.; González Muñoz, A.; González, M. M.; Goodman, J. A.; Hampel-Arias, Z.; Harding, J. P.; Hernandez-Almada, A.; Hinton, J.; Hueyotl-Zahuantitla, F.; Hui, C. M.; Hüntemeyer, P.; Iriarte, A.; Jardin-Blicq, A.; Joshi, V.; Kaufmann, S.; Lara, A.; Lauer, R. J.; Lennarz, D.; León Vargas, H.; Linnemann, J. T.; Longinotti, A. L.; Luis Raya, G.; Luna-García, R.; López-Cámara, D.; López-Coto, R.; Malone, K.; Marinelli, S. S.; Martinez, O.; Martinez-Castellanos, I.; Martínez-Castro, J.; Martínez-Huerta, H.; Matthews, J. A.; Miranda-Romagnoli, P.; Moreno, E.; Mostafá, M.; Nellen, L.; Newbold, M.; Nisa, M. U.; Noriega-Papaqui, R.; Pelayo, R.; Pretz, J.; Pérez-Pérez, E. G.; Ren, Z.; Rho, C. D.; Rivière, C.; Rosa-González, D.; Rosenberg, M.; Ruiz-Velasco, E.; Salesa Greus, F.; Sandoval, A.; Schneider, M.; Schoorlemmer, H.; Sinnis, G.; Smith, A. J.; Springer, R. W.; Surajbali, P.; Taboada, I.; Tibolla, O.; Tollefson, K.; Torres, I.; Ukwatta, T. N.; Villaseñor, L.; Weisgarber, T.; Westerhoff, S.; Wood, J.; Yapici, T.; Zepeda, A.; Zhou, H.; HAWC Collaboration

2017-12-01

We report on the measurement of the all-particle cosmic ray energy spectrum with the High Altitude Water Cherenkov (HAWC) Observatory in the energy range 10 to 500 TeV. HAWC is a ground-based air-shower array deployed on the slopes of Volcan Sierra Negra in the state of Puebla, Mexico, and is sensitive to gamma rays and cosmic rays at TeV energies. The data used in this work were taken over 234 days between June 2016 and February 2017. The primary cosmic-ray energy is determined with a maximum likelihood approach using the particle density as a function of distance to the shower core. Introducing quality cuts to isolate events with shower cores landing on the array, the reconstructed energy distribution is unfolded iteratively. The measured all-particle spectrum is consistent with a broken power law with an index of -2.49 ±0.01 prior to a break at (45.7 ±0.1 ) TeV , followed by an index of -2.71 ±0.01 . The spectrum also represents a single measurement that spans the energy range between direct detection and ground-based experiments. As a verification of the detector response, the energy scale and angular resolution are validated by observation of the cosmic ray Moon shadow's dependence on energy.

Corrections on energy spectrum and scattering for fast neutron radiography at NECTAR facility

International Nuclear Information System (INIS)

Liu Shuquan; Thomas, Boucherl; Li Hang; Zou Yubin; Lu Yuanrong; Guo Zhiyu

2013-01-01

Distortions caused by the neutron spectrum and scattered neutrons are major problems in fast neutron radiography and should be considered for improving the image quality. This paper puts emphasis on the removal of these image distortions and deviations for fast neutron radiography performed at the NECTAR facility of the research reactor FRM-Ⅱ in Technische Universitaet Mounchen (TUM), Germany. The NECTAR energy spectrum is analyzed and established to modify the influence caused by the neutron spectrum, and the Point Scattered Function (PScF) simulated by the Monte-Carlo program MCNPX is used to evaluate scattering effects from the object and improve image quality. Good analysis results prove the sound effects of the above two corrections. (authors)

Corrections on energy spectrum and scatterings for fast neutron radiography at NECTAR facility

Science.gov (United States)

Liu, Shu-Quan; Bücherl, Thomas; Li, Hang; Zou, Yu-Bin; Lu, Yuan-Rong; Guo, Zhi-Yu

2013-11-01

Distortions caused by the neutron spectrum and scattered neutrons are major problems in fast neutron radiography and should be considered for improving the image quality. This paper puts emphasis on the removal of these image distortions and deviations for fast neutron radiography performed at the NECTAR facility of the research reactor FRM- II in Technische Universität München (TUM), Germany. The NECTAR energy spectrum is analyzed and established to modify the influence caused by the neutron spectrum, and the Point Scattered Function (PScF) simulated by the Monte-Carlo program MCNPX is used to evaluate scattering effects from the object and improve image quality. Good analysis results prove the sound effects of the above two corrections.

Time-resolved energy spectrum of a pseudospark-produced high-brightness electron beam

International Nuclear Information System (INIS)

Myers, T.J.; Ding, B.N.; Rhee, M.J.

1992-01-01

The pseudospark, a fast low-pressure gas discharge between a hollow cathode and a planar anode, is found to be an interesting high-brightness electron beam source. Typically, all electron beam produced in the pseudospark has the peak current of ∼1 kA, pulse duration of ∼50 ns, and effective emittance of ∼100 mm-mrad. The energy information of this electron beam, however, is least understood due to the difficulty of measuring a high-current-density beam that is partially space-charge neutralized by the background ions produced in the gas. In this paper, an experimental study of the time-resolved energy spectrum is presented. The pseudospark produced electron beam is injected into a vacuum through a small pinhole so that the electrons without background ions follow single particle motion; the beam is sent through a negative biased electrode and the only portion of beam whose energy is greater than the bias voltage can pass through the electrode and the current is measured by a Faraday cup. The Faraday cup signals with various bias voltage are recorded in a digital oscilloscope. The recorded waveforms are then numerically analyzed to construct a time-resolved energy spectrum. Preliminary results are presented

The measurement of tripartition alpha particle low energy spectrum in 235U fission induced by thermal neutrons

International Nuclear Information System (INIS)

El Hage Sleiman, F.

1980-01-01

The energy spectrum of the α particles emitted in the thermal neutron induced fission of 235 U was measured from 11.5 MeV down to 2 MeV using the parabola mass spectrometer Lohengrin at the ILL high flux reactor. A Monte Carlo program, that simulates the α particle motion to the spectrometer, has been developed. Numerical results of Monte Carlo calculations for differents values of parameter are reported. The overall energy spectrum is slightly asymmetric at low energy. The possible reasons for the existence of this asymmetry are discussed [fr

Integration of Semiconducting Sulfides for Full-Spectrum Solar Energy Absorption and Efficient Charge Separation.

Science.gov (United States)

Zhuang, Tao-Tao; Liu, Yan; Li, Yi; Zhao, Yuan; Wu, Liang; Jiang, Jun; Yu, Shu-Hong

2016-05-23

The full harvest of solar energy by semiconductors requires a material that simultaneously absorbs across the whole solar spectrum and collects photogenerated electrons and holes separately. The stepwise integration of three semiconducting sulfides, namely ZnS, CdS, and Cu2-x S, into a single nanocrystal, led to a unique ternary multi-node sheath ZnS-CdS-Cu2-x S heteronanorod for full-spectrum solar energy absorption. Localized surface plasmon resonance (LSPR) in the nonstoichiometric copper sulfide nanostructures enables effective NIR absorption. More significantly, the construction of pn heterojunctions between Cu2-x S and CdS leads to staggered gaps, as confirmed by first-principles simulations. This band alignment causes effective electron-hole separation in the ternary system and hence enables efficient solar energy conversion. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The inverse of winnowing: a FORTRAN subroutine and discussion of unwinnowing discrete data

Science.gov (United States)

Bracken, Robert E.

2004-01-01

This report describes an unwinnowing algorithm that utilizes a discrete Fourier transform, and a resulting Fortran subroutine that winnows or unwinnows a 1-dimensional stream of discrete data; the source code is included. The unwinnowing algorithm effectively increases (by integral factors) the number of available data points while maintaining the original frequency spectrum of a data stream. This has utility when an increased data density is required together with an availability of higher order derivatives that honor the original data.

Composition and energy spectrum variations of auroral ions

International Nuclear Information System (INIS)

Lynch, J.; Leach, R.; Pulliam, D.; Scherb, F.

1977-01-01

We have detected H + ,O + , and He ++ ions with E/q up to 20 keV/charge in a hydrogen aurora over Churchill, Manitoba, during the flight of a Javelin sounding rocket on February 11, 1975, We observed several examples of different types of ion events. One type consisted of bursts of H + and O + ions which arrived simultaneously at all energies within the range of the E/q analyzer. These events were apparently of local origin (distance + ions (O + /H + approximately-greater-than30%). A second type of event consisted of bursts of enhanced H + counting rates but no O + ions. The dispersion in time of the energy spectrum was consistent with an injection and acceleration site located at about 20 R/sub E/ from the earth. An enhancement of the He ++ counting rates was associated with these events, but the He ++ data are of limited statistical significance. A third type of event, consisting of short bursts of H + ions with wide energy spreads, was observed in association with an event in which the energy of the H + ions showed time dispersion. We interpret these short H + bursts as due to ions trapped in traveling waves generated by an explosive injection of plasma in the earth's magnetotail

Dose rate constant and energy spectrum of interstitial brachytherapy sources

International Nuclear Information System (INIS)

Chen Zhe; Nath, Ravinder

2001-01-01

In the past two years, several new manufacturers have begun to market low-energy interstitial brachytherapy seeds containing 125 I and 103 Pd. Parallel to this development, the National Institute of Standards and Technology (NIST) has implemented a modification to the air-kerma strength (S K ) standard for 125 I seeds and has also established an S K standard for 103 Pd seeds. These events have generated a considerable number of investigations on the determination of the dose rate constants (Λ) of interstitial brachytherapy seeds. The aim of this work is to study the general properties underlying the determination of Λ and to develop a simple method for a quick and accurate estimation of Λ. As the dose rate constant of clinical seeds is defined at a fixed reference point, we postulated that Λ may be calculated by treating the seed as an effective point source when the seed's source strength is specified in S K and its source characteristics are specified by the photon energy spectrum measured in air at the reference point. Using a semi-analytic approach, an analytic expression for Λ was derived for point sources with known photon energy spectra. This approach enabled a systematic study of Λ as a function of energy. Using the measured energy spectra, the calculated Λ for 125 I model 6711 and 6702 seeds and for 192 Ir seed agreed with the AAPM recommended values within ±1%. For the 103 Pd model 200 seed, the agreement was 5% with a recently measured value (within the ±7% experimental uncertainty) and was within 1% with the Monte Carlo simulations. The analytic expression for Λ proposed here can be evaluated using a programmable calculator or a simple spreadsheet and it provides an efficient method for checking the measured dose rate constant for any interstitial brachytherapy seed once the energy spectrum of the seed is known

Evaluation of the Neutron Detector Response for Cosmic Ray Energy Spectrum by Monte Carlo Transport Simulation

International Nuclear Information System (INIS)

Pazianotto, Mauricio T.; Carlson, Brett V.; Federico, Claudio A.; Gonzalez, Odair L.

2011-01-01

Neutrons generated by the interaction of cosmic rays with the atmosphere make an important contribution to the dose accumulated in electronic circuits and aircraft crew members at flight altitude. High-energy neutrons are produced in spallation reactions and intranuclear cascade processes by primary cosmic-ray particle interactions with atoms in the atmosphere. These neutrons can produce secondary neutrons and also undergo a moderation process due to atmosphere interactions, resulting in a wider energy spectrum, ranging from thermal energies (0.025 eV) to energies of several hundreds of MeV. The Long-Counter (LC) detector is a widely used neutron detector designed to measure the directional flux of neutrons with about constant response over a wide energy range (thermal to 20 MeV). ). Its calibration process and the determination of its energy response for the wide-energy of cosmic ray induced neutron spectrum is a very difficult process due to the lack of installations with these capabilities. The goal of this study is to assess the behavior of the response of a Long Counter using the Monte Carlo (MC) computational code MCNPX (Monte Carlo N-Particle eXtended). The dependence of the Long Counter response on the angle of incidence, as well as on the neutron energy, will be carefully investigated, compared with the experimental data previously obtained with 241 Am-Be and 252 Cf neutron sources and extended to the neutron spectrum produced by cosmic rays. (Author)

THE COSMIC-RAY ENERGY SPECTRUM OBSERVED WITH THE SURFACE DETECTOR OF THE TELESCOPE ARRAY EXPERIMENT

Energy Technology Data Exchange (ETDEWEB)

Abu-Zayyad, T.; Allen, M.; Anderson, R.; Barcikowski, E.; Belz, J. W.; Bergman, D. R.; Blake, S. A.; Cady, R.; Hanlon, W. [High Energy Astrophysics Institute and Department of Physics and Astronomy, University of Utah, Salt Lake City, Utah (United States); Aida, R. [University of Yamanashi, Interdisciplinary Graduate School of Medicine and Engineering, Kofu, Yamanashi (Japan); Azuma, R.; Fukuda, T. [Graduate School of Science and Engineering, Tokyo Institute of Technology, Meguro, Tokyo (Japan); Cheon, B. G.; Cho, E. J. [Department of Physics and Research Institute of Natural Science, Hanyang University, Seongdong-gu, Seoul (Korea, Republic of); Chiba, J. [Department of Physics, Tokyo University of Science, Noda, Chiba (Japan); Chikawa, M. [Department of Physics, Kinki University, Higashi Osaka, Osaka (Japan); Cho, W. R. [Department of Physics, Yonsei University, Seodaemun-gu, Seoul (Korea, Republic of); Fujii, H. [Institute of Particle and Nuclear Studies, KEK, Tsukuba, Ibaraki (Japan); Fujii, T. [Graduate School of Science, Osaka City University, Osaka, Osaka (Japan); Fukushima, M. [Institute for Cosmic Ray Research, University of Tokyo, Kashiwa, Chiba (Japan); and others

2013-05-01

The Telescope Array (TA) collaboration has measured the energy spectrum of ultra-high energy cosmic rays (UHECRs) with primary energies above 1.6 Multiplication-Sign 10{sup 18} eV. This measurement is based upon four years of observation by the surface detector component of TA. The spectrum shows a dip at an energy of 4.6 Multiplication-Sign 10{sup 18} eV and a steepening at 5.4 Multiplication-Sign 10{sup 19} eV which is consistent with the expectation from the GZK cutoff. We present the results of a technique, new to the analysis of UHECR surface detector data, that involves generating a complete simulation of UHECRs striking the TA surface detector. The procedure starts with shower simulations using the CORSIKA Monte Carlo program where we have solved the problems caused by use of the ''thinning'' approximation. This simulation method allows us to make an accurate calculation of the acceptance of the detector for the energies concerned.

Spectrum and energy levels of the sodiumlike ion Sr/sup 27+/

International Nuclear Information System (INIS)

Reader, J.

1986-01-01

The spectrum of Sr/sup 27+/ was observed with a laser-produced plasma and a 2.2-m grazing-incidence spectrograph in the region 12--160 A-circle. From the identification of 37 lines, a system of 27 energy levels of the type 2p 6 nl was determined. The level system includes the configurations ns(n = 3-5), np(n = 3-6), nd(n = 3-7), nf(n = 4-6), and 5g. The ionization energy is determined as 11 188200 +- 1000 cm/sup -1/ (1387.16 +- 0.12 eV)

Quantum superposition of the state discrete spectrum of mathematical correlation molecule for small samples of biometric data

Directory of Open Access Journals (Sweden)

Vladimir I. Volchikhin

2017-06-01

Full Text Available Introduction: The study promotes to decrease a number of errors of calculating the correlation coefficient in small test samples. Materials and Methods: We used simulation tool for the distribution functions of the density values of the correlation coefficient in small samples. A method for quantization of the data, allows obtaining a discrete spectrum states of one of the varieties of correlation functional. This allows us to consider the proposed structure as a mathematical correlation molecule, described by some analogue continuous-quantum Schrödinger equation. Results: The chi-squared Pearson’s molecule on small samples allows enhancing power of classical chi-squared test to 20 times. A mathematical correlation molecule described in the article has similar properties. It allows in the future reducing calculation errors of the classical correlation coefficients in small samples. Discussion and Conclusions: The authors suggest that there are infinitely many mathematical molecules are similar in their properties to the actual physical molecules. Schrödinger equations are not unique, their analogues can be constructed for each mathematical molecule. You can expect a mathematical synthesis of molecules for a large number of known statistical tests and statistical moments. All this should make it possible to reduce calculation errors due to quantum effects that occur in small test samples.

Effects of X-rays spectrum on the dose; Efectos del espectro de rayos X sobre la dosis

Energy Technology Data Exchange (ETDEWEB)

Rodriguez I, J. L.; Hernandez A, P. L.; Vega C, H. R. [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas (Mexico); Rivera M, T., E-mail: johann_greenday@hotmail.com [IPN, Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada, Av. Legaria No. 694, 11500 Mexico D. F. (Mexico)

2015-10-15

The X-ray equipment for diagnosis comes in different sizes and shapes depending on the scan type to perform. The X-ray spectrum is the energy distribution of the beam photons and consists of a continuous spectrum of photons braking and discrete spectrum due to the characteristic photons. The knowledge of the X-rays spectrum is important to understand like they affect the voltage changes (k Vp), current (m A), time (s) and the type of filter in the interaction mechanisms between X-rays and patient's body, the image receptor or other material that gets in the beam. Across the spectrum can be estimated the absorbed dose in any point of the patient, the quality of the image and the scattered radiation (which is related to the dose received by the equipment operator). The Monte Carlo method was used by MCNP5 code to calculate the spectrum of X-rays that occurs when a monoenergetic electron beam of 250 keV interact with targets of Mo, Rh and W. The spectra were calculated with and without filter, and the values of ambient dose equivalent were estimated, as well as the air kerma. (Author)

Magnetic diffusion effects on the ultra-high energy cosmic ray spectrum and composition

Energy Technology Data Exchange (ETDEWEB)

Mollerach, Silvia; Roulet, Esteban, E-mail: mollerach@cab.cnea.gov.ar, E-mail: roulet@cab.cnea.gov.ar [CONICET, Centro Atómico Bariloche, Av. Bustillo 9500 (8400) (Argentina)

2013-10-01

We discuss the effects of diffusion of high energy cosmic rays in turbulent extra-galactic magnetic fields. We find an approximate expression for the low energy suppression of the spectrum of the different mass components (with charge Z) in the case in which this suppression happens at energies below ∼ Z EeV, so that energy losses are dominated by the adiabatic ones. The low energy suppression appears when cosmic rays from the closest sources take a time comparable to the age of the Universe to reach the Earth. This occurs for energies E < Z EeV (B/nG)√(l{sub c}/Mpc)(d{sub s}/70Mpc) in terms of the magnetic field RMS strength B, its coherence length l{sub c} and the typical separation between sources d{sub s}. We apply this to scenarios in which the sources produce a mixed composition and have a relatively low maximum rigidity (E{sub max} ∼ (2–10)Z EeV), finding that diffusion has a significant effect on the resulting spectrum, the average mass and on its spread, in particular reducing this last one. For reasonable values of B and l{sub c} these effects can help to reproduce the composition trends observed by the Auger Collaboration for source spectra compatible with Fermi acceleration.

First-principles modeling of electromagnetic scattering by discrete and discretely heterogeneous random media

Science.gov (United States)

Mishchenko, Michael I.; Dlugach, Janna M.; Yurkin, Maxim A.; Bi, Lei; Cairns, Brian; Liu, Li; Panetta, R. Lee; Travis, Larry D.; Yang, Ping; Zakharova, Nadezhda T.

2018-01-01

A discrete random medium is an object in the form of a finite volume of a vacuum or a homogeneous material medium filled with quasi-randomly and quasi-uniformly distributed discrete macroscopic impurities called small particles. Such objects are ubiquitous in natural and artificial environments. They are often characterized by analyzing theoretically the results of laboratory, in situ, or remote-sensing measurements of the scattering of light and other electromagnetic radiation. Electromagnetic scattering and absorption by particles can also affect the energy budget of a discrete random medium and hence various ambient physical and chemical processes. In either case electromagnetic scattering must be modeled in terms of appropriate optical observables, i.e., quadratic or bilinear forms in the field that quantify the reading of a relevant optical instrument or the electromagnetic energy budget. It is generally believed that time-harmonic Maxwell’s equations can accurately describe elastic electromagnetic scattering by macroscopic particulate media that change in time much more slowly than the incident electromagnetic field. However, direct solutions of these equations for discrete random media had been impracticable until quite recently. This has led to a widespread use of various phenomenological approaches in situations when their very applicability can be questioned. Recently, however, a new branch of physical optics has emerged wherein electromagnetic scattering by discrete and discretely heterogeneous random media is modeled directly by using analytical or numerically exact computer solutions of the Maxwell equations. Therefore, the main objective of this Report is to formulate the general theoretical framework of electromagnetic scattering by discrete random media rooted in the Maxwell–Lorentz electromagnetics and discuss its immediate analytical and numerical consequences. Starting from the microscopic Maxwell–Lorentz equations, we trace the development

First-principles modeling of electromagnetic scattering by discrete and discretely heterogeneous random media

International Nuclear Information System (INIS)

Mishchenko, Michael I.; Dlugach, Janna M.; Yurkin, Maxim A.; Bi, Lei; Cairns, Brian; Liu, Li; Panetta, R. Lee; Travis, Larry D.; Yang, Ping; Zakharova, Nadezhda T.

2016-01-01

A discrete random medium is an object in the form of a finite volume of a vacuum or a homogeneous material medium filled with quasi-randomly and quasi-uniformly distributed discrete macroscopic impurities called small particles. Such objects are ubiquitous in natural and artificial environments. They are often characterized by analyzing theoretically the results of laboratory, in situ, or remote-sensing measurements of the scattering of light and other electromagnetic radiation. Electromagnetic scattering and absorption by particles can also affect the energy budget of a discrete random medium and hence various ambient physical and chemical processes. In either case electromagnetic scattering must be modeled in terms of appropriate optical observables, i.e., quadratic or bilinear forms in the field that quantify the reading of a relevant optical instrument or the electromagnetic energy budget. It is generally believed that time-harmonic Maxwell’s equations can accurately describe elastic electromagnetic scattering by macroscopic particulate media that change in time much more slowly than the incident electromagnetic field. However, direct solutions of these equations for discrete random media had been impracticable until quite recently. This has led to a widespread use of various phenomenological approaches in situations when their very applicability can be questioned. Recently, however, a new branch of physical optics has emerged wherein electromagnetic scattering by discrete and discretely heterogeneous random media is modeled directly by using analytical or numerically exact computer solutions of the Maxwell equations. Therefore, the main objective of this Report is to formulate the general theoretical framework of electromagnetic scattering by discrete random media rooted in the Maxwell–Lorentz electromagnetics and discuss its immediate analytical and numerical consequences. Starting from the microscopic Maxwell–Lorentz equations, we trace the development

First-principles modeling of electromagnetic scattering by discrete and discretely heterogeneous random media

Energy Technology Data Exchange (ETDEWEB)

Mishchenko, Michael I., E-mail: michael.i.mishchenko@nasa.gov [NASA Goddard Institute for Space Studies, 2880 Broadway, New York, NY 10025 (United States); Dlugach, Janna M. [Main Astronomical Observatory of the National Academy of Sciences of Ukraine, 27 Zabolotny Str., 03680, Kyiv (Ukraine); Yurkin, Maxim A. [Voevodsky Institute of Chemical Kinetics and Combustion, SB RAS, Institutskaya str. 3, 630090 Novosibirsk (Russian Federation); Novosibirsk State University, Pirogova 2, 630090 Novosibirsk (Russian Federation); Bi, Lei [Department of Atmospheric Sciences, Texas A& M University, College Station, TX 77843 (United States); Cairns, Brian [NASA Goddard Institute for Space Studies, 2880 Broadway, New York, NY 10025 (United States); Liu, Li [NASA Goddard Institute for Space Studies, 2880 Broadway, New York, NY 10025 (United States); Columbia University, 2880 Broadway, New York, NY 10025 (United States); Panetta, R. Lee [Department of Atmospheric Sciences, Texas A& M University, College Station, TX 77843 (United States); Travis, Larry D. [NASA Goddard Institute for Space Studies, 2880 Broadway, New York, NY 10025 (United States); Yang, Ping [Department of Atmospheric Sciences, Texas A& M University, College Station, TX 77843 (United States); Zakharova, Nadezhda T. [Trinnovim LLC, 2880 Broadway, New York, NY 10025 (United States)

2016-05-16

A discrete random medium is an object in the form of a finite volume of a vacuum or a homogeneous material medium filled with quasi-randomly and quasi-uniformly distributed discrete macroscopic impurities called small particles. Such objects are ubiquitous in natural and artificial environments. They are often characterized by analyzing theoretically the results of laboratory, in situ, or remote-sensing measurements of the scattering of light and other electromagnetic radiation. Electromagnetic scattering and absorption by particles can also affect the energy budget of a discrete random medium and hence various ambient physical and chemical processes. In either case electromagnetic scattering must be modeled in terms of appropriate optical observables, i.e., quadratic or bilinear forms in the field that quantify the reading of a relevant optical instrument or the electromagnetic energy budget. It is generally believed that time-harmonic Maxwell’s equations can accurately describe elastic electromagnetic scattering by macroscopic particulate media that change in time much more slowly than the incident electromagnetic field. However, direct solutions of these equations for discrete random media had been impracticable until quite recently. This has led to a widespread use of various phenomenological approaches in situations when their very applicability can be questioned. Recently, however, a new branch of physical optics has emerged wherein electromagnetic scattering by discrete and discretely heterogeneous random media is modeled directly by using analytical or numerically exact computer solutions of the Maxwell equations. Therefore, the main objective of this Report is to formulate the general theoretical framework of electromagnetic scattering by discrete random media rooted in the Maxwell–Lorentz electromagnetics and discuss its immediate analytical and numerical consequences. Starting from the microscopic Maxwell–Lorentz equations, we trace the development

First-Principles Modeling Of Electromagnetic Scattering By Discrete and Discretely Heterogeneous Random Media

Science.gov (United States)

Mishchenko, Michael I.; Dlugach, Janna M.; Yurkin, Maxim A.; Bi, Lei; Cairns, Brian; Liu, Li; Panetta, R. Lee; Travis, Larry D.; Yang, Ping; Zakharova, Nadezhda T.

2016-01-01

A discrete random medium is an object in the form of a finite volume of a vacuum or a homogeneous material medium filled with quasi-randomly and quasi-uniformly distributed discrete macroscopic impurities called small particles. Such objects are ubiquitous in natural and artificial environments. They are often characterized by analyzing theoretically the results of laboratory, in situ, or remote-sensing measurements of the scattering of light and other electromagnetic radiation. Electromagnetic scattering and absorption by particles can also affect the energy budget of a discrete random medium and hence various ambient physical and chemical processes. In either case electromagnetic scattering must be modeled in terms of appropriate optical observables, i.e., quadratic or bilinear forms in the field that quantify the reading of a relevant optical instrument or the electromagnetic energy budget. It is generally believed that time-harmonic Maxwell's equations can accurately describe elastic electromagnetic scattering by macroscopic particulate media that change in time much more slowly than the incident electromagnetic field. However, direct solutions of these equations for discrete random media had been impracticable until quite recently. This has led to a widespread use of various phenomenological approaches in situations when their very applicability can be questioned. Recently, however, a new branch of physical optics has emerged wherein electromagnetic scattering by discrete and discretely heterogeneous random media is modeled directly by using analytical or numerically exact computer solutions of the Maxwell equations. Therefore, the main objective of this Report is to formulate the general theoretical framework of electromagnetic scattering by discrete random media rooted in the Maxwell- Lorentz electromagnetics and discuss its immediate analytical and numerical consequences. Starting from the microscopic Maxwell-Lorentz equations, we trace the development of

Microstructural evolution of pure tungsten neutron irradiated with a mixed energy spectrum

Energy Technology Data Exchange (ETDEWEB)

Koyanagi, Takaaki, E-mail: koyanagit@ornl.gov [Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Kumar, N.A.P. Kiran [Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Hwang, Taehyun [Tohoku University, Sendai, 980-8579 (Japan); Garrison, Lauren M.; Hu, Xunxiang [Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Snead, Lance L. [Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Katoh, Yutai [Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States)

2017-07-15

Microstructures of single-crystal bulk tungsten (W) and polycrystalline W foil with a strong grain texture were investigated using transmission electron microscopy following neutron irradiation at ∼90–800 °C to 0.03–4.6 displacements per atom (dpa) in the High Flux Isotope Reactor with a mixed energy spectrum. The dominant irradiation defects were dislocation loops and small clusters at ∼90 °C. Additional voids were formed in W irradiated at above 460 °C. Voids and precipitates involving transmutation rhenium and osmium were the dominant defects at more than ∼1 dpa. We found a new phenomenon of microstructural evolution in irradiated polycrystalline W: Re- and Os-rich precipitation along grain boundaries. Comparison of results between this study and previous studies using different irradiation facilities revealed that the microstructural evolution of pure W is highly dependent on the neutron energy spectrum in addition to the irradiation temperature and dose.

An extended discrete gradient formula for oscillatory Hamiltonian systems

International Nuclear Information System (INIS)

Liu Kai; Shi Wei; Wu Xinyuan

2013-01-01

In this paper, incorporating the idea of the discrete gradient method into the extended Runge–Kutta–Nyström integrator, we derive and analyze an extended discrete gradient formula for the oscillatory Hamiltonian system with the Hamiltonian H(p,q)= 1/2 p T p+ 1/2 q T Mq+U(q), where q:R→R d represents generalized positions, p:R→R d represents generalized momenta and M is an element of R dxd is a symmetric and positive semi-definite matrix. The solution of this system is a nonlinear oscillator. Basically, many nonlinear oscillatory mechanical systems with a partitioned Hamiltonian function lend themselves to this approach. The extended discrete gradient formula presented in this paper exactly preserves the energy H(p, q). We derive some properties of the new formula. The convergence is analyzed for the implicit schemes based on the discrete gradient formula, and it turns out that the convergence of the implicit schemes based on the extended discrete gradient formula is independent of ‖M‖, which is a significant property for the oscillatory Hamiltonian system. Thus, it transpires that a larger step size can be chosen for the new energy-preserving schemes than that for the traditional discrete gradient methods when applied to the oscillatory Hamiltonian system. Illustrative examples show the competence and efficiency of the new schemes in comparison with the traditional discrete gradient methods in the scientific literature. (paper)

Energy and spectrum of BeO molecule under the electric field from different directions

NARCIS (Netherlands)

Jiang, M.; Guo, F. J.; Yan, A. Y.; Zhang, C. W.; Miao, F.

2010-01-01

Based on the density functional theory DFT/ B3LYP at 6-311g level, the ground states of BeO molecule are optimized. The effects of electric field on the bond length, the system energy, the charge distribution, the energy levels, the HOMO-LUMO gaps and the infrared spectrum of BeO molecule are

Direct Discrete Method for Neutronic Calculations

International Nuclear Information System (INIS)

Vosoughi, Naser; Akbar Salehi, Ali; Shahriari, Majid

2002-01-01

The objective of this paper is to introduce a new direct method for neutronic calculations. This method which is named Direct Discrete Method, is simpler than the neutron Transport equation and also more compatible with physical meaning of problems. This method is based on physic of problem and with meshing of the desired geometry, writing the balance equation for each mesh intervals and with notice to the conjunction between these mesh intervals, produce the final discrete equations series without production of neutron transport differential equation and mandatory passing from differential equation bridge. We have produced neutron discrete equations for a cylindrical shape with two boundary conditions in one group energy. The correction of the results from this method are tested with MCNP-4B code execution. (authors)

Gabor's expansion and the Zak transform for continuous-time and discrete-time signals : critical sampling and rational oversampling

NARCIS (Netherlands)

Bastiaans, M.J.

1995-01-01

Gabor's expansion of a signal into a discrete set of shifted and modulated versions of an elementary signal is introduced and its relation to sampling of the sliding-window spectrum is shown. It is shown how Gabor's expansion coefficients can be found as samples of the sliding-window spectrum, where

Discrete Tomography and Imaging of Polycrystalline Structures

DEFF Research Database (Denmark)

Alpers, Andreas

High resolution transmission electron microscopy is commonly considered as the standard application for discrete tomography. While this has yet to be technically realized, new applications with a similar flavor have emerged in materials science. In our group at Ris� DTU (Denmark's National...... Laboratory for Sustainable Energy), for instance, we study polycrystalline materials via synchrotron X-ray diffraction. Several reconstruction problems arise, most of them exhibit inherently discrete aspects. In this talk I want to give a concise mathematical introduction to some of these reconstruction...... problems. Special focus is on their relationship to classical discrete tomography. Several open mathematical questions will be mentioned along the way....

Approximate albedo boundary conditions for energy multigroup X,Y-geometry discrete ordinates nuclear global calculations

Energy Technology Data Exchange (ETDEWEB)

Silva, Davi J.M.; Nunes, Carlos E.A.; Alves Filho, Hermes; Barros, Ricardo C., E-mail: davijmsilva@yahoo.com.br, E-mail: ceanunes@yahoo.com.br, E-mail: rcbarros@pq.cnpq.br [Secretaria Municipal de Educacao de Itaborai, RJ (Brazil); Universidade Estacio de Sa (UNESA), Rio de Janeiro, RJ (Brazil); Universidade do Estado do Rio de Janeiro (UERJ), Novra Friburgo, RJ (Brazil). Instituto Politecnico. Departamento de Modelagem Computacional

2017-11-01

Discussed here is the accuracy of approximate albedo boundary conditions for energy multigroup discrete ordinates (S{sub N}) eigenvalue problems in two-dimensional rectangular geometry for criticality calculations in neutron fission reacting systems, such as nuclear reactors. The multigroup (S{sub N}) albedo matrix substitutes approximately the non-multiplying media around the core, e.g., baffle and reflector, as we neglect the transverse leakage terms within these non-multiplying regions. Numerical results to a typical model problem are given to illustrate the accuracy versus the computer running time. (author)

Energy spectrum of two-dimensional tight-binding electrons in a spatially varying magnetic field

International Nuclear Information System (INIS)

Oh, G.Y.; Lee, M.H.

1996-01-01

The electronic energy spectrum of a two-dimensional lattice in a spatially varying magnetic field is studied within the framework of the tight-binding model by using the scheme of the transfer matrix. It is found that, in comparison with the case of a uniform magnetic field, the energy spectrum exhibits more complicated behavior; band broadening (or gap closing) and band splitting (or gap opening) occur depending on characteristic parameters of the lattice. The origin of these phenomena lies in the existence of direct touching and indirect overlapping between neighboring subbands. Dependence of direct touching and indirect overlapping, and thus the electronic band structure together with the density of states, on characteristic parameters of the lattice is elucidated in detail. copyright 1996 The American Physical Society

Prompt neutron fission spectrum mean energies for the fissile nuclides and 252Cf

International Nuclear Information System (INIS)

Holden, N.E.

1985-01-01

The international standard for a neutron spectrum is that produced from the spontaneous fission of 252 Cf, while the thermal neutron induced fission neutron spectra for the four fissile nuclides, 233 U, 235 U, 239 Pu, and 241 Pu are of interest from the standpoint of nuclear reactors. The average neutron energies of these spectra are tabulated. The individual measurements are recorded with the neutron energy range measured, the method of detection as well as the average neutron energy for each author. Also tabulated are the measurements of the ratio of mean energies for pairs of fission neutron spectra. 75 refs., 9 tabs

Improved method for solving the neutron transport problem by discretization of space and energy variables

International Nuclear Information System (INIS)

Bosevski, T.

1971-01-01

The polynomial interpolation of neutron flux between the chosen space and energy variables enabled transformation of the integral transport equation into a system of linear equations with constant coefficients. Solutions of this system are the needed values of flux for chosen values of space and energy variables. The proposed improved method for solving the neutron transport problem including the mathematical formalism is simple and efficient since the number of needed input data is decreased both in treating the spatial and energy variables. Mathematical method based on this approach gives more stable solutions with significantly decreased probability of numerical errors. Computer code based on the proposed method was used for calculations of one heavy water and one light water reactor cell, and the results were compared to results of other very precise calculations. The proposed method was better concerning convergence rate, decreased computing time and needed computer memory. Discretization of variables enabled direct comparison of theoretical and experimental results

Neutron energy spectrum determination near the surface on the JET vacuum vessel using the multifoil activation technique

Energy Technology Data Exchange (ETDEWEB)

Pillon, M.; Jarvis, O.N.; Conroy, S. (Associazione EURATOM-ENEA sulla Fusione, Frascati (Italy) JET Joint Undertaking, Abingdonm Oxon (U.K.) Imperial College of Science, Technology and Medicine, London (U.K.))

1990-03-01

The activation of foils of zinc, indium, aluminium, copper and magnesium has been used as a means of examining the energy spectrum of neutrons produced by discharges in the Joint European Torus (JET). Several threshold reactions have been used together with a least-squares unfolding code to determine the 2.5 and 14 MeV neutron yields produced by the JET plasma. The analysis shows that the energy spectrum produced by downscattered neutrons is satisfactorily calculated with the MCNP neutron transport code.

Structures in the primary spectrum

International Nuclear Information System (INIS)

Kempa, J.; Knurenko, S.P.; Malecki, R.

2009-01-01

Structures in the energy spectrum of primary cosmic rays at the 'knee' region and for energies higher than 1 EeV are obtained through studying extensive air showers (EAS). The main problem of the research is the fact that we work in the ranges of highly fluctuating parameters used to obtain the primary energy spectrum. In this paper the log-normal distribution for the error function has been used in convolution with the power spectrum to explain the Yakutsk experimental data. Similar results have been obtained for the gamma distribution as the error function. Using the power law primary spectrum in the energy region around 10 19 eV we will argue that the primary Yakutsk spectrum is overestimated. In the best case this overestimation is not less than 42%.

Theory and simulation of discrete kinetic beta induced Alfven eigenmode in tokamak plasmas

International Nuclear Information System (INIS)

Wang, X; Zonca, F; Chen, L

2010-01-01

It is shown, both analytically and by numerical simulations, that, in the presence of thermal ion kinetic effects, the beta induced Alfven eigenmode (BAE)-shear Alfven wave continuous spectrum can be discretized into radially trapped eigenstates known as kinetic BAE (KBAE). While thermal ion compressibility gives rise to finite BAE accumulation point frequency, the discretization occurs via the finite Larmor radius and finite orbit width effects. Simulations and analytical theories agree both qualitatively and quantitatively. Simulations also demonstrate that KBAE can be readily excited by the finite radial gradients of energetic particles.

Design and Analysis of Hybrid Solar Lighting and Full-Spectrum Solar Energy Systems

International Nuclear Information System (INIS)

Muhs, J.D.

2001-01-01

This paper describes a systems-level design and analysis of a new approach for improving the energy efficiency and affordability of solar energy in buildings, namely, hybrid solar lighting and full-spectrum solar energy systems. By using different portions of the solar spectrum simultaneously for multiple end-use applications in buildings, the proposed system offers unique advantages over other alternatives for using sunlight to displace electricity (conventional topside daylighting and solar technologies). Our preliminary work indicates that hybrid solar lighting, a method of collecting and distributing direct sunlight for lighting purposes, will alleviate many of the problems with passive daylighting systems of today, such as spatial and temporal variability, glare, excess illumination, cost, and energy efficiency. Similarly, our work suggests that the most appropriate use of the visible portion of direct, nondiffuse sunlight from an energy-savings perspective is to displace electric light rather than generate electricity. Early estimates detailed in this paper suggest an anticipated system cost of well under$2.0/Wp and 5-11(cents)/kWh for displaced and generated electricity in single-story commercial building applications. Based on a number of factors discussed in the paper, including sunlight availability, building use scenarios, time-of-day electric utility rates, cost, and efficacy of the displaced electric lights, the simple payback of this approach in many applications could eventually be well under 5 years

Critical experiments analyses by using 70 energy group library based on ENDF/B-VI

Energy Technology Data Exchange (ETDEWEB)

Tahara, Yoshihisa; Matsumoto, Hideki [Mitsubishi Heavy Industries Ltd., Yokohama (Japan). Nuclear Energy Systems Engineering Center; Huria, H.C.; Ouisloumen, M.

1998-03-01

The newly developed 70-group library has been validated by comparing kinf from a continuous energy Monte-Carlo code MCNP and two dimensional spectrum calculation code PHOENIX-CP. The code employs Discrete Angular Flux Method based on Collision Probability. The library has been also validated against a large number of critical experiments and numerical benchmarks for assemblies with MOX and Gd fuels. (author)

Dark Energy Constraints from the Thermal Sunyaev Zeldovich Power Spectrum

Science.gov (United States)

Bolliet, Boris; Comis, Barbara; Komatsu, Eiichiro; Macías-Pérez, Juan Francisco

2018-03-01

We constrain the dark energy equation of state parameter, w, using the power spectrum of the thermal Sunyaev-Zeldovich (tSZ) effect. We improve upon previous analyses by taking into account the trispectrum in the covariance matrix and marginalising over the foreground parameters, the correlated noise, the mass bias B in the Planck universal pressure profile, and all the relevant cosmological parameters (i.e., not just Ωm and σ8). We find that the amplitude of the tSZ power spectrum at ℓ ≲ 103 depends primarily on F ≡ σ8(Ωm/B)0.40h-0.21, where B is related to more commonly used variable b by B = (1 - b)-1. We measure this parameter with 2.6% precision, F = 0.460 ± 0.012 (68% CL). By fixing the bias to B = 1.25 and adding the local determination of the Hubble constant H0 and the amplitude of the primordial power spectrum constrained by the Planck Cosmic Microwave Background (CMB) data, we find w = -1.10 ± 0.12, σ8 = 0.802 ± 0.037, and Ωm = 0.265 ± 0.022 (68% CL). Our limit on w is consistent with and is as tight as that from the distance-alone constraint from the CMB and H0. Finally, by combining the tSZ power spectrum and the CMB data we find, in the Λ Cold Dark Matter (CDM) model, the mass bias of B = 1.71 ± 0.17, i.e., 1 - b = 0.58 ± 0.06 (68% CL).

Discrete expansions of continuum functions. General concepts

International Nuclear Information System (INIS)

Bang, J.; Ershov, S.N.; Gareev, F.A.; Kazacha, G.S.

1979-01-01

Different discrete expansions of the continuum wave functions are considered: pole expansion (according to the Mittag-Lefler theorem), Weinberg states. The general property of these groups of states is their completeness in the finite region of space. They satisfy the Schroedinger type equations and are matched with free solutions of the Schroedinger equation at the boundary. Convergence of expansions for the S matrix, the Green functions and the continuous-spectrum wave functions is studied. A new group of states possessing the best convergence is introduced

Local box-counting dimensions of discrete quantum eigenvalue spectra: Analytical connection to quantum spectral statistics

Science.gov (United States)

Sakhr, Jamal; Nieminen, John M.

2018-03-01

Two decades ago, Wang and Ong, [Phys. Rev. A 55, 1522 (1997)], 10.1103/PhysRevA.55.1522 hypothesized that the local box-counting dimension of a discrete quantum spectrum should depend exclusively on the nearest-neighbor spacing distribution (NNSD) of the spectrum. In this Rapid Communication, we validate their hypothesis by deriving an explicit formula for the local box-counting dimension of a countably-infinite discrete quantum spectrum. This formula expresses the local box-counting dimension of a spectrum in terms of single and double integrals of the NNSD of the spectrum. As applications, we derive an analytical formula for Poisson spectra and closed-form approximations to the local box-counting dimension for spectra having Gaussian orthogonal ensemble (GOE), Gaussian unitary ensemble (GUE), and Gaussian symplectic ensemble (GSE) spacing statistics. In the Poisson and GOE cases, we compare our theoretical formulas with the published numerical data of Wang and Ong and observe excellent agreement between their data and our theory. We also study numerically the local box-counting dimensions of the Riemann zeta function zeros and the alternate levels of GOE spectra, which are often used as numerical models of spectra possessing GUE and GSE spacing statistics, respectively. In each case, the corresponding theoretical formula is found to accurately describe the numerically computed local box-counting dimension.

Discrete Mathematics

DEFF Research Database (Denmark)

Sørensen, John Aasted

2011-01-01

The objectives of Discrete Mathematics (IDISM2) are: The introduction of the mathematics needed for analysis, design and verification of discrete systems, including the application within programming languages for computer systems. Having passed the IDISM2 course, the student will be able...... to accomplish the following: -Understand and apply formal representations in discrete mathematics. -Understand and apply formal representations in problems within discrete mathematics. -Understand methods for solving problems in discrete mathematics. -Apply methods for solving problems in discrete mathematics......; construct a finite state machine for a given application. Apply these concepts to new problems. The teaching in Discrete Mathematics is a combination of sessions with lectures and students solving problems, either manually or by using Matlab. Furthermore a selection of projects must be solved and handed...

Development of analytical software for semi-quantitative analysis of x-ray spectrum acquired from energy-dispersive spectrometer

International Nuclear Information System (INIS)

Karim, A.; Rana, M.A.; Qamar, R.; Latif, A; Ahmad, M.; Farooq, M.A.; Ahmad, Z.

2003-12-01

Software package for elemental analysis for X-ray spectrum obtained from Energy Dispersive Spectrometer (EDS) attached with Scanning Electron Microscope (SEM) has been developed: A Personal Computer Analyzer card PCA-800 is used to acquire data from the EDS. This spectrum is obtained in binary format, which is transformed into ASCII format using PCAII card software. The program is modular in construction and coded using Microsoft's QUICKBASIC compiler linker. Energy line library containing all lines of elements is created for analysis of acquired characteristic X-ray spectrum. Two techniques of peak identification are provided. Statistical tools are employed for smoothing of a curve and for computing area under the curve. Elemental concentration is calculated in weight % and in atomic. (author)

The energy spectrum of cosmic-ray electrons measured with H.E.S.S

International Nuclear Information System (INIS)

Egberts, Kathrin

2009-01-01

The spectrum of cosmic-ray electrons has so far been measured using balloon and satellite-based instruments. At TeV energies, however, the sensitivity of such instruments is very limited due to the low flux of electrons at very high energies and small detection areas of balloon/satellite based experiments. The very large collection area of ground-based imaging atmospheric Cherenkov telescopes gives them a substantial advantage over balloon/ satellite based instruments when detecting very-high-energy electrons (> 300 GeV). By analysing data taken by the High Energy Stereoscopic System (H.E.S.S.), this work extends the known electron spectrum up to 4 TeV - a range that is not accessible to direct measurements. However, in contrast to direct measurements, imaging atmospheric Cherenkov telescopes such as H.E.S.S. detect air showers that cosmic-ray electrons initiate in the atmosphere rather than the primary particle. Thus, the main challenge is to differentiate between air showers initiated by electrons and those initiated by the hadronic background. A new analysis technique was developed that determines the background with the support of the machine-learning algorithm Random Forest. It is shown that this analysis technique can also be applied in other areas such as the analysis of diffuse γ rays from the Galactic plane. (orig.)

The energy spectrum of cosmic-ray electrons measured with H.E.S.S.

Energy Technology Data Exchange (ETDEWEB)

Egberts, Kathrin

2009-03-30

The spectrum of cosmic-ray electrons has so far been measured using balloon and satellite-based instruments. At TeV energies, however, the sensitivity of such instruments is very limited due to the low flux of electrons at very high energies and small detection areas of balloon/satellite based experiments. The very large collection area of ground-based imaging atmospheric Cherenkov telescopes gives them a substantial advantage over balloon/ satellite based instruments when detecting very-high-energy electrons (> 300 GeV). By analysing data taken by the High Energy Stereoscopic System (H.E.S.S.), this work extends the known electron spectrum up to 4 TeV - a range that is not accessible to direct measurements. However, in contrast to direct measurements, imaging atmospheric Cherenkov telescopes such as H.E.S.S. detect air showers that cosmic-ray electrons initiate in the atmosphere rather than the primary particle. Thus, the main challenge is to differentiate between air showers initiated by electrons and those initiated by the hadronic background. A new analysis technique was developed that determines the background with the support of the machine-learning algorithm Random Forest. It is shown that this analysis technique can also be applied in other areas such as the analysis of diffuse {gamma} rays from the Galactic plane. (orig.)

The anisotropy of cosmic ray particles in the energy range 1011-1019 eV

International Nuclear Information System (INIS)

Xu Chunxian

1985-01-01

A study of the anisotropy of primary cosmic ray is presented. The expression of the anisotropy is derived in a model of statistical discrete sources in an infinite galaxy. Using these derived formulas, the amplitudes of the first harmonic anisotropies caused by eleven supernovea nearby the Earth are estimated individually and the trend of the resultant anisotropy is investigated. It is found that the expected results can account for the power law of Esup(0.5) of the anisotropy above the energy 5 x 10 15 eV. The Compton-getting effect can cause an additional anisotropy which is independent of energy and added to the resultant anisotropy of these discrete sources. It is apparent that the anisotropies available in the low energy range 10 11 - 10 14 eV are caused by the Compton-Getting effect. Taking the differential spectrum index γ = 2.67 measured in the same energy bound we get the streaming velocity of 35 km/s with respect to the cosmic ray background

Baecklund transformations for discrete Painleve equations: Discrete PII-PV

International Nuclear Information System (INIS)

Sakka, A.; Mugan, U.

2006-01-01

Transformation properties of discrete Painleve equations are investigated by using an algorithmic method. This method yields explicit transformations which relates the solutions of discrete Painleve equations, discrete P II -P V , with different values of parameters. The particular solutions which are expressible in terms of the discrete analogue of the classical special functions of discrete Painleve equations can also be obtained from these transformations

Benchmarking of EPRI-cell epithermal methods with the point-energy discrete-ordinates code (OZMA)

International Nuclear Information System (INIS)

Williams, M.L.; Wright, R.Q.; Barhen, J.; Rothenstein, W.

1982-01-01

The purpose of the present study is to benchmark E-C resonance-shielding and cell-averaging methods against a rigorous deterministic solution on a fine-group level (approx. 30 groups between 1 eV and 5.5 keV). The benchmark code used is OZMA, which solves the space-dependent slowing-down equations using continuous-energy discrete ordinates or integral transport theory to produce fine-group cross sections. Results are given for three water-moderated lattices - a mixed oxide, a uranium method, and a tight-pitch high-conversion uranium oxide configuration. The latter two lattices were chosen because of the strong self shielding of the 238 U resonances

Discrete-ordinates finite-element method for atmospheric radiative transfer and remote sensing

International Nuclear Information System (INIS)

Gerstl, S.A.W.; Zardecki, A.

1985-01-01

Advantages and disadvantages of modern discrete-ordinates finite-element methods for the solution of radiative transfer problems in meteorology, climatology, and remote sensing applications are evaluated. After the common basis of the formulation of radiative transfer problems in the fields of neutron transport and atmospheric optics is established, the essential features of the discrete-ordinates finite-element method are described including the limitations of the method and their remedies. Numerical results are presented for 1-D and 2-D atmospheric radiative transfer problems where integral as well as angular dependent quantities are compared with published results from other calculations and with measured data. These comparisons provide a verification of the discrete-ordinates results for a wide spectrum of cases with varying degrees of absorption, scattering, and anisotropic phase functions. Accuracy and computational speed are also discussed. Since practically all discrete-ordinates codes offer a builtin adjoint capability, the general concept of the adjoint method is described and illustrated by sample problems. Our general conclusion is that the strengths of the discrete-ordinates finite-element method outweight its weaknesses. We demonstrate that existing general-purpose discrete-ordinates codes can provide a powerful tool to analyze radiative transfer problems through the atmosphere, especially when 2-D geometries must be considered

Discrete quantum geometries and their effective dimension

International Nuclear Information System (INIS)

Thuerigen, Johannes

2015-01-01

In several approaches towards a quantum theory of gravity, such as group field theory and loop quantum gravity, quantum states and histories of the geometric degrees of freedom turn out to be based on discrete spacetime. The most pressing issue is then how the smooth geometries of general relativity, expressed in terms of suitable geometric observables, arise from such discrete quantum geometries in some semiclassical and continuum limit. In this thesis I tackle the question of suitable observables focusing on the effective dimension of discrete quantum geometries. For this purpose I give a purely combinatorial description of the discrete structures which these geometries have support on. As a side topic, this allows to present an extension of group field theory to cover the combinatorially larger kinematical state space of loop quantum gravity. Moreover, I introduce a discrete calculus for fields on such fundamentally discrete geometries with a particular focus on the Laplacian. This permits to define the effective-dimension observables for quantum geometries. Analysing various classes of quantum geometries, I find as a general result that the spectral dimension is more sensitive to the underlying combinatorial structure than to the details of the additional geometric data thereon. Semiclassical states in loop quantum gravity approximate the classical geometries they are peaking on rather well and there are no indications for stronger quantum effects. On the other hand, in the context of a more general model of states which are superposition over a large number of complexes, based on analytic solutions, there is a flow of the spectral dimension from the topological dimension d on low energy scales to a real number between 0 and d on high energy scales. In the particular case of 1 these results allow to understand the quantum geometry as effectively fractal.

Measuring the low-energy cosmic ray spectrum with the AFIS detector

Energy Technology Data Exchange (ETDEWEB)

Losekamm, Martin [Physics Department E18, Technische Universitaet Muenchen (Germany); Institute of Astronautics, Technische Universitaet Muenchen (Germany); Gaisbauer, Dominic; Greenwald, Daniel; Hahn, Alexander; Hauptmann, Philipp; Konorov, Igor; Meng, Lingxin; Paul, Stephan; Poeschl, Thomas [Physics Department E18, Technische Universitaet Muenchen (Germany); Renker, Dieter [Physics Department E17, Technische Universitaet Muenchen (Germany)

2014-07-01

High-energy cosmic rays interact with Earth's upper atmosphere and produce antiprotons, which can be trapped in Earth's magnetic field. The Antiproton Flux in Space (AFIS) Mission will measure the flux of trapped antiprotons with energies less than 100 MeV aboard the nanosatellite MOVE 2. An active-target tracking detector comprised of scintillating plastic fibers and silicon photomultipliers is already under construction at the Technische Universitaet Muenchen. As a precursor to the space-bound mission, a prototype version of the detector will be launched aboard a balloon from Kiruna, Sweden as part of the REXUS/BEXUS student program by the German Aerospace Center (DLR). Named AFIS-P, it will be used to measure the low-energy part of the cosmic-ray spectrum for energies less than 100 MeV-per-nucleon. Spectrometers in previous balloon missions were not sensitive in this low-energy region. Thus AFIS-P will deliver unprecedented data, while simultaneously allowing us to field-test the AFIS detector.

Dark discrete gauge symmetries

International Nuclear Information System (INIS)

Batell, Brian

2011-01-01

We investigate scenarios in which dark matter is stabilized by an Abelian Z N discrete gauge symmetry. Models are surveyed according to symmetries and matter content. Multicomponent dark matter arises when N is not prime and Z N contains one or more subgroups. The dark sector interacts with the visible sector through the renormalizable kinetic mixing and Higgs portal operators, and we highlight the basic phenomenology in these scenarios. In particular, multiple species of dark matter can lead to an unconventional nuclear recoil spectrum in direct detection experiments, while the presence of new light states in the dark sector can dramatically affect the decays of the Higgs at the Tevatron and LHC, thus providing a window into the gauge origin of the stability of dark matter.

Discrete Curvature Theories and Applications

KAUST Repository

Sun, Xiang

2016-08-25

Discrete Di erential Geometry (DDG) concerns discrete counterparts of notions and methods in di erential geometry. This thesis deals with a core subject in DDG, discrete curvature theories on various types of polyhedral surfaces that are practically important for free-form architecture, sunlight-redirecting shading systems, and face recognition. Modeled as polyhedral surfaces, the shapes of free-form structures may have to satisfy di erent geometric or physical constraints. We study a combination of geometry and physics { the discrete surfaces that can stand on their own, as well as having proper shapes for the manufacture. These proper shapes, known as circular and conical meshes, are closely related to discrete principal curvatures. We study curvature theories that make such surfaces possible. Shading systems of freeform building skins are new types of energy-saving structures that can re-direct the sunlight. From these systems, discrete line congruences across polyhedral surfaces can be abstracted. We develop a new curvature theory for polyhedral surfaces equipped with normal congruences { a particular type of congruences de ned by linear interpolation of vertex normals. The main results are a discussion of various de nitions of normality, a detailed study of the geometry of such congruences, and a concept of curvatures and shape operators associated with the faces of a triangle mesh. These curvatures are compatible with both normal congruences and the Steiner formula. In addition to architecture, we consider the role of discrete curvatures in face recognition. We use geometric measure theory to introduce the notion of asymptotic cones associated with a singular subspace of a Riemannian manifold, which is an extension of the classical notion of asymptotic directions. We get a simple expression of these cones for polyhedral surfaces, as well as convergence and approximation theorems. We use the asymptotic cones as facial descriptors and demonstrate the

CHANDRA HIGH-ENERGY TRANSMISSION GRATING SPECTRUM OF AE AQUARII

International Nuclear Information System (INIS)

Mauche, Christopher W.

2009-01-01

The nova-like cataclysmic binary AE Aqr, which is currently understood to be a former supersoft X-ray binary and current magnetic propeller, was observed for over two binary orbits (78 ks) in 2005 August with the High-Energy Transmission Grating (HETG) on board the Chandra X-ray Observatory. The long, uninterrupted Chandra observation provides a wealth of details concerning the X-ray emission of AE Aqr, many of which are new and unique to the HETG. First, the X-ray spectrum is that of an optically thin multi-temperature thermal plasma; the X-ray emission lines are broad, with widths that increase with the line energy from σ ∼ 1 eV (510 km s -1 ) for O VIII to σ ∼ 5.5 eV (820 km s -1 ) for Si XIV; the X-ray spectrum is reasonably well fit by a plasma model with a Gaussian emission measure distribution that peaks at log T(K) = 7.16, has a width σ = 0.48, an Fe abundance equal to 0.44 times solar, and other metal (primarily Ne, Mg, and Si) abundances equal to 0.76 times solar; and for a distance d = 100 pc, the total emission measure EM = 8.0 x 10 53 cm -3 and the 0.5-10 keV luminosity L X = 1.1 x 10 31 erg s -1 . Second, based on the f/(i + r) flux ratios of the forbidden (f), intercombination (i), and recombination (r) lines of the Heα triplets of N VI, O VII, and Ne IX measured by Itoh et al. in the XMM-Newton Reflection Grating Spectrometer spectrum and those of O VII, Ne IX, Mg XI, and Si XIII in the Chandra HETG spectrum, either the electron density of the plasma increases with temperature by over three orders of magnitude, from n e ∼ 6 x 10 10 cm -3 for N VI [log T(K) ∼ 6] to n e ∼ 1 x 10 14 cm -3 for Si XIII [log T(K) ∼ 7], and/or the plasma is significantly affected by photoexcitation. Third, the radial velocity of the X-ray emission lines varies on the white dwarf spin phase, with two oscillations per spin cycle and an amplitude K ∼ 160 km s -1 . These results appear to be inconsistent with the recent models of Itoh et al., Ikhsanov, and

Spectrum of the Wilson Dirac operator at finite lattice spacings

DEFF Research Database (Denmark)

Akemann, G.; Damgaard, Poul Henrik; Splittorff, Kim

2011-01-01

We consider the effect of discretization errors on the microscopic spectrum of the Wilson Dirac operator using both chiral Perturbation Theory and chiral Random Matrix Theory. A graded chiral Lagrangian is used to evaluate the microscopic spectral density of the Hermitian Wilson Dirac operator...... as well as the distribution of the chirality over the real eigenvalues of the Wilson Dirac operator. It is shown that a chiral Random Matrix Theory for the Wilson Dirac operator reproduces the leading zero-momentum terms of Wilson chiral Perturbation Theory. All results are obtained for fixed index...... of the Wilson Dirac operator. The low-energy constants of Wilson chiral Perturbation theory are shown to be constrained by the Hermiticity properties of the Wilson Dirac operator....

PROBING THE INFLATON: SMALL-SCALE POWER SPECTRUM CONSTRAINTS FROM MEASUREMENTS OF THE COSMIC MICROWAVE BACKGROUND ENERGY SPECTRUM

International Nuclear Information System (INIS)

Chluba, Jens; Erickcek, Adrienne L.; Ben-Dayan, Ido

2012-01-01

In the early universe, energy stored in small-scale density perturbations is quickly dissipated by Silk damping, a process that inevitably generates μ- and y-type spectral distortions of the cosmic microwave background (CMB). These spectral distortions depend on the shape and amplitude of the primordial power spectrum at wavenumbers k ∼ 4 Mpc –1 . Here, we study constraints on the primordial power spectrum derived from COBE/FIRAS and forecasted for PIXIE. We show that measurements of μ and y impose strong bounds on the integrated small-scale power, and we demonstrate how to compute these constraints using k-space window functions that account for the effects of thermalization and dissipation physics. We show that COBE/FIRAS places a robust upper limit on the amplitude of the small-scale power spectrum. This limit is about three orders of magnitude stronger than the one derived from primordial black holes in the same scale range. Furthermore, this limit could be improved by another three orders of magnitude with PIXIE, potentially opening up a new window to early universe physics. To illustrate the power of these constraints, we consider several generic models for the small-scale power spectrum predicted by different inflation scenarios, including running-mass inflation models and inflation scenarios with episodes of particle production. PIXIE could place very tight constraints on these scenarios, potentially even ruling out running-mass inflation models if no distortion is detected. We also show that inflation models with sub-Planckian field excursion that generate detectable tensor perturbations should simultaneously produce a large CMB spectral distortion, a link that could potentially be established with PIXIE.

Discretized representations of harmonic variables by bilateral Jacobi operators

Directory of Open Access Journals (Sweden)

Andreas Ruffing

2000-01-01

Full Text Available Starting from a discrete Heisenberg algebra we solve several representation problems for a discretized quantum oscillator in a weighted sequence space. The Schrödinger operator for a discrete harmonic oscillator is derived. The representation problem for a q-oscillator algebra is studied in detail. The main result of the article is the fact that the energy representation for the discretized momentum operator can be interpreted as follows: It allows to calculate quantum properties of a large number of non-interacting harmonic oscillators at the same time. The results can be directly related to current research on squeezed laser states in quantum optics. They reveal and confirm the observation that discrete versions of continuum Schrodinger operators allow more structural freedom than their continuum analogs do.

Determination of the neutrons energy spectrum in the central thimble of the reactor core TRIGA Mark III

International Nuclear Information System (INIS)

Parra M, M. A.; Luis L, M. A.; Raya A, R.; Cruz G, H. S.

2013-10-01

This work presents the measurement of the neutrons spectrum in energies in the central thimble of the reactor TRIGA Mark III to a power of 1 MW in stationary state, with the core in the center of the pool. To achieve this objective, several thin sheets were irradiated (one at the time) in the same position of the core. The activation probes were selected in such a way that covered the energy range (1 x 10 -10 to 20 MeV) of the neutrons spectrum in the reactor core, for this purpose thin sheets were used of 197 Au, 58 Ni, 115 In, 24 Mg, 27 Al, 58 Fe, 59 Co and 63 Cu. After the irradiation, the high energy gamma emissions of the activated thin sheets were measured by means of gamma spectrometry, in a counting system of high resolution, with a Hyper pure Germanium detector, obtaining this way the activity induced in the thin sheets whose magnitude is proportional to the intensity of the neutrons flow, this activity together to a theoretical initial spectrum are the main entrance data of the computational code SANDBP (Hungarian version of the code Sand-II) that uses the unfolding method for the calculation of the spectrum. (Author)

First-order discrete Faddeev gravity at strongly varying fields

Science.gov (United States)

Khatsymovsky, V. M.

2017-11-01

We consider the Faddeev formulation of general relativity (GR), which can be characterized by a kind of d-dimensional tetrad (typically d = 10) and a non-Riemannian connection. This theory is invariant w.r.t. the global, but not local, rotations in the d-dimensional space. There can be configurations with a smooth or flat metric, but with the tetrad that changes abruptly at small distances, a kind of “antiferromagnetic” structure. Previously, we discussed a first-order representation for the Faddeev gravity, which uses the orthogonal connection in the d-dimensional space as an independent variable. Using the discrete form of this formulation, we considered the spectrum of (elementary) area. This spectrum turns out to be physically reasonable just on a classical background with large connection like rotations by π, that is, with such an “antiferromagnetic” structure. In the discrete first-order Faddeev gravity, we consider such a structure with periodic cells and large connection and strongly changing tetrad field inside the cell. We show that this system in the continuum limit reduces to a generalization of the Faddeev system. The action is a sum of related actions of the Faddeev type and is still reduced to the GR action.

Polarimetry of coherent bremsstrahlung by analysis of the photon energy spectrum

International Nuclear Information System (INIS)

Darbinyan, S.; Hakobyan, H.; Jones, R.; Sirunyan, A.; Vartapetian, H.

2005-01-01

A method of coherent bremsstrahlung (CB) polarimetry based on the analysis of the shape of the photon energy spectrum is presented. The influence of a number of uncertainty sources, including the choice of atomic form-factors, has been analyzed. For a CB source consisting of a diamond radiator and multi-GeV electrons, an absolute accuracy of polarimetry at the level of 0.01-0.02 is attainable

A preliminary layout and PIC simulations of the time resolved beam energy spectrum measurement for DRAGON-I

International Nuclear Information System (INIS)

Liao Shuqing; Zhang Kaizhi; Shi Jingshui

2010-01-01

The time resolved beam energy spectrum for DRAGON-I can be measured with a new method which is named RBS (Rotating Beam in Solenoid). The beam energy spectrum is determined by measuring the beam rotation angle and its expansion width at the exit of DRAGON-I. The rotation beam is shaped by a slit at the exit of DRAGON-I, then rotated in the magnetic field of the solenoids and the resulted beamlet is measured by the Cherenkov screen. The beam motion in the solenoids is simulated by PARMELA and the relationships between the beam rotation angle's expansion width and the beam energy spread, emittance are discussed. The measurement error is also discussed in this paper. (authors)

On the infimum of the energy-momentum spectrum of a homogeneous Bose gas

DEFF Research Database (Denmark)

Cornean, Horia; Derezinski, J.; Zin, P.

2009-01-01

We consider second-quantized homogeneous Bose gas in a large cubic box with periodic boundary conditions at zero temperature. We discuss the energy-momentum spectrum of the Bose gas and its physical significance. We review various rigorous and heuristic results as well as open conjectures about its...

Comparison of RF spectrum prediction methods for dynamic spectrum access

Science.gov (United States)

Kovarskiy, Jacob A.; Martone, Anthony F.; Gallagher, Kyle A.; Sherbondy, Kelly D.; Narayanan, Ram M.

2017-05-01

Dynamic spectrum access (DSA) refers to the adaptive utilization of today's busy electromagnetic spectrum. Cognitive radio/radar technologies require DSA to intelligently transmit and receive information in changing environments. Predicting radio frequency (RF) activity reduces sensing time and energy consumption for identifying usable spectrum. Typical spectrum prediction methods involve modeling spectral statistics with Hidden Markov Models (HMM) or various neural network structures. HMMs describe the time-varying state probabilities of Markov processes as a dynamic Bayesian network. Neural Networks model biological brain neuron connections to perform a wide range of complex and often non-linear computations. This work compares HMM, Multilayer Perceptron (MLP), and Recurrent Neural Network (RNN) algorithms and their ability to perform RF channel state prediction. Monte Carlo simulations on both measured and simulated spectrum data evaluate the performance of these algorithms. Generalizing spectrum occupancy as an alternating renewal process allows Poisson random variables to generate simulated data while energy detection determines the occupancy state of measured RF spectrum data for testing. The results suggest that neural networks achieve better prediction accuracy and prove more adaptable to changing spectral statistics than HMMs given sufficient training data.

Primary CR energy spectrum and mass composition by the data of Tunka-133 array

Directory of Open Access Journals (Sweden)

Prosin V.V.

2015-01-01

Full Text Available The Cherenkov light array for the registration of extensive air showers (EAS Tunka-133 collected data during 5 winter seasons from 2009 to 2014. The differential energy spectrum of all particles and the dependence of the average maximum depth on the energy in the range of 6 ⋅ 1015–1018 eV measured for 1540 hours of observation are presented.

Discrete nature of thermodynamics in confined ideal Fermi gases

International Nuclear Information System (INIS)

Aydin, Alhun; Sisman, Altug

2014-01-01

Intrinsic discrete nature in thermodynamic properties of Fermi gases appears under strongly confined and degenerate conditions. For a rectangular confinement domain, thermodynamic properties of an ideal Fermi gas are expressed in their exact summation forms. For 1D, 2D and 3D nano domains, variations of both number of particles and internal energy per particle with chemical potential are examined. It is shown that their relation with chemical potential exhibits a discrete nature which allows them to take only some definite values. Furthermore, quasi-irregular oscillatory-like sharp peaks are observed in heat capacity. New nano devices can be developed based on these behaviors. - Highlights: • “Discrete behaviors” appear in thermodynamic properties of ideal Fermi gases at nano scale. • Variations of particle number and internal energy with chemical potential have stepwise behavior. • There are oscillations and peaks in the variation of heat capacity with domain size and particle number. • Fermi line and Fermi surface at nano scale are not continuous but “discrete”. • Heat capacity oscillations can be used for excess thermal energy storage at nano scale

Structure of the discrete Dirac vacuum in the sigma + omega model

International Nuclear Information System (INIS)

Miller, L.D.

1989-01-01

The sigma + omega model potentials imply that any moderate to large nucleus should have thousands of discrete negative-energy nucleon states. Theoretical predictions of structure in this discrete island of the nuclear Dirac sea are presented in this paper. This structure is related to the spectral functions that will emerge in high energy electron- and hardon-induced reactions on nuclei. These high-energy reaction studies should supplement our understanding of the saturation mechanism of the sigma + omega model. They could also identify the threshold for observable quantum chromo-dynamics (QCD) effects in nuclei

Discrete Curvatures and Discrete Minimal Surfaces

KAUST Repository

Sun, Xiang

2012-01-01

This thesis presents an overview of some approaches to compute Gaussian and mean curvature on discrete surfaces and discusses discrete minimal surfaces. The variety of applications of differential geometry in visualization and shape design leads

The Cosmic Ray Energy Spectrum and Related Measurements with the Pierre Auger Observatory

Energy Technology Data Exchange (ETDEWEB)

Abraham, : J.; Abreu, P.; Aglietta, M.; Aguirre, C.; Ahn, E.J.; Allard, D.; Allekotte, I.; Allen, J.; Alvarez-Muniz, J.; Ambrosio, M.; Anchordoqui, L.

2009-06-01

These are presentations to be presented at the 31st International Cosmic Ray Conference, in Lodz, Poland during July 2009. It consists of the following presentations: (1) Measurement of the cosmic ray energy spectrum above 10{sup 18} eV with the Pierre Auger Observatory; (2) The cosmic ray flux observed at zenith angles larger than 60 degrees with the Pierre Auger Observatory; (3) Energy calibration of data recorded with the surface detectors of the Pierre Auger Observatory; (4) Exposure of the Hybrid Detector of The Pierre Auger Observatory; and (5) Energy scale derived from Fluorescence Telescopes using Cherenkov Light and Shower Universality.

Determination of r Factor of Kalbach-Mann Systematics for Energy Balance

International Nuclear Information System (INIS)

Zhang Jingshang

2008-01-01

Kalbach-Mann systematics is a very useful formula to discrete the double-differential cross sections of emitted particles. However, the energy balance by using this systematics is still a task to be studied. In the form of Legendre polynomial expansion the energy balance has been proved analytically. In terms of this approach, the formula to determine the pre-equilibrium fraction r factor of Kalbach-Mann systematics has been obtained for keeping energy balance strictly. This formula could be straightforwardly applied for describing the double-differential cross sections of all projectile types in the continuum spectrum emissions. It indicates that Legendre expansion coefficient with l = 1 is the key term in the energy balance

Indoor measurement of photovoltaic device characteristics at varying irradiance, temperature and spectrum for energy rating

International Nuclear Information System (INIS)

Bliss, M; Betts, T R; Gottschalg, R

2010-01-01

The first three-dimensional performance matrix for use in photovoltaic (PV) energy rating is reported utilizing a novel energy rating solar simulator based on LEDs. Device characteristics are measured indoors at varying irradiance (G), temperature (T) and spectrum (E). This opens the possibility for a more accurate measurement system for energy yield prediction of PV devices, especially for devices with high spectral dependence such as wide bandgap solar cells as they take into account spectral changes in the light. The main aspects of the LED-based solar simulator used are briefly described. A measurement method is developed and detailed in the paper, which takes into account the current imperfections in the achievable spectrum. Measurement results for a crystalline silicon solar cell are used to demonstrate the measurement approach. An uncertainty analysis of the measurement system is given, resulting in an overall absolute uncertainty of 4.3% (coverage factor k = 2) in maximum power measurements at 765 W m −2 irradiance with scope for further improvements

An Energy-Efficient Spectrum-Aware Reinforcement Learning-Based Clustering Algorithm for Cognitive Radio Sensor Networks.

Science.gov (United States)

Mustapha, Ibrahim; Mohd Ali, Borhanuddin; Rasid, Mohd Fadlee A; Sali, Aduwati; Mohamad, Hafizal

2015-08-13

It is well-known that clustering partitions network into logical groups of nodes in order to achieve energy efficiency and to enhance dynamic channel access in cognitive radio through cooperative sensing. While the topic of energy efficiency has been well investigated in conventional wireless sensor networks, the latter has not been extensively explored. In this paper, we propose a reinforcement learning-based spectrum-aware clustering algorithm that allows a member node to learn the energy and cooperative sensing costs for neighboring clusters to achieve an optimal solution. Each member node selects an optimal cluster that satisfies pairwise constraints, minimizes network energy consumption and enhances channel sensing performance through an exploration technique. We first model the network energy consumption and then determine the optimal number of clusters for the network. The problem of selecting an optimal cluster is formulated as a Markov Decision Process (MDP) in the algorithm and the obtained simulation results show convergence, learning and adaptability of the algorithm to dynamic environment towards achieving an optimal solution. Performance comparisons of our algorithm with the Groupwise Spectrum Aware (GWSA)-based algorithm in terms of Sum of Square Error (SSE), complexity, network energy consumption and probability of detection indicate improved performance from the proposed approach. The results further reveal that an energy savings of 9% and a significant Primary User (PU) detection improvement can be achieved with the proposed approach.

Finite-element discretization of 3D energy-transport equations for semiconductors

Energy Technology Data Exchange (ETDEWEB)

Gadau, Stephan

2007-07-01

In this thesis a mathematical model was derived that describes the charge and energy transport in semiconductor devices like transistors. Moreover, numerical simulations of these physical processes are performed. In order to accomplish this, methods of theoretical physics, functional analysis, numerical mathematics and computer programming are applied. After an introduction to the status quo of semiconductor device simulation methods and a brief review of historical facts up to now, the attention is shifted to the construction of a model, which serves as the basis of the subsequent derivations in the thesis. Thereby the starting point is an important equation of the theory of dilute gases. From this equation the model equations are derived and specified by means of a series expansion method. This is done in a multi-stage derivation process, which is mainly taken from a scientific paper and which does not constitute the focus of this thesis. In the following phase we specify the mathematical setting and make precise the model assumptions. Thereby we make use of methods of functional analysis. Since the equations we deal with are coupled, we are concerned with a nonstandard problem. In contrary, the theory of scalar elliptic equations is established meanwhile. Subsequently, we are preoccupied with the numerical discretization of the equations. A special finite-element method is used for the discretization. This special approach has to be done in order to make the numerical results appropriate for practical application. By a series of transformations from the discrete model we derive a system of algebraic equations that are eligible for numerical evaluation. Using self-made computer programs we solve the equations to get approximate solutions. These programs are based on new and specialized iteration procedures that are developed and thoroughly tested within the frame of this research work. Due to their importance and their novel status, they are explained and

Strong water absorption in the dayside emission spectrum of the planet HD 189733b.

Science.gov (United States)

Grillmair, Carl J; Burrows, Adam; Charbonneau, David; Armus, Lee; Stauffer, John; Meadows, Victoria; van Cleve, Jeffrey; von Braun, Kaspar; Levine, Deborah

2008-12-11

Recent observations of the extrasolar planet HD 189733b did not reveal the presence of water in the emission spectrum of the planet. Yet models of such 'hot-Jupiter' planets predict an abundance of atmospheric water vapour. Validating and constraining these models is crucial to understanding the physics and chemistry of planetary atmospheres in extreme environments. Indications of the presence of water in the atmosphere of HD 189733b have recently been found in transmission spectra, where the planet's atmosphere selectively absorbs the light of the parent star, and in broadband photometry. Here we report the detection of strong water absorption in a high-signal-to-noise, mid-infrared emission spectrum of the planet itself. We find both a strong downturn in the flux ratio below 10 microm and discrete spectral features that are characteristic of strong absorption by water vapour. The differences between these and previous observations are significant and admit the possibility that predicted planetary-scale dynamical weather structures may alter the emission spectrum over time. Models that match the observed spectrum and the broadband photometry suggest that heat redistribution from the dayside to the nightside is weak. Reconciling this with the high nightside temperature will require a better understanding of atmospheric circulation or possible additional energy sources.

Dependence of effective spectrum width of synchrotron radiation on particle energy

Energy Technology Data Exchange (ETDEWEB)

Bagrov, V.G. [Tomsk State University, Department of Physics, Tomsk (Russian Federation); Institute of High Current Electronics, Tomsk (Russian Federation); University of Sao Paulo, Institute of Physics, Sao Paulo (Brazil); Gitman, D.M. [Tomsk State University, Department of Physics, Tomsk (Russian Federation); University of Sao Paulo, Institute of Physics, Sao Paulo (Brazil); P.N. Lebedev Physical Institute, Moscow (Russian Federation); Levin, A.D. [University of Sao Paulo, Institute of Physics, Sao Paulo (Brazil); Loginov, A.S.; Saprykin, A.D. [Tomsk State University, Department of Physics, Tomsk (Russian Federation)

2017-05-15

In the classical theory of synchrotron radiation, for the exact quantitative characterization of spectral properties, the concept of effective spectral width is introduced. In the first part of our work, published in EJPC 75 (2015), the effective spectral width as a function of the energy E of the radiating particle was obtained only in the ultra-relativistic approximation. In this article, which can be considered as a natural continuation of this work, a complete investigation is presented of the dependence of the effective width of the synchrotron radiation spectrum on energy for any values of E and for all the polarization components of the radiation. Numerical calculations were carried out for an effective width not exceeding 100 harmonics. (orig.)

Discrete Bogomolny equations for the nonlinear O(3) σ model in 2+1 dimensions

International Nuclear Information System (INIS)

Leese, R.

1989-01-01

Discrete analogues of the topological charge and of the Bogomolny equations are constructed for the nonlinear O(3) σ model in 2+1 dimensions, subject to the restriction that the energy density be radially symmetric. These are then incorporated into a discretized version of the evolution equations. Using the discrete Bogomolny relations to construct the initial data for numerical simulations removes the ''lattice wobble'' sometimes observed at low kinetic energies. This feature is very important for the delicate question of instanton stability

Energy Efficient Cooperative Spectrum Sensing in Cognitive Radio Networks Using Distributed Dynamic Load Balanced Clustering Scheme

Directory of Open Access Journals (Sweden)

Muthukkumar R.

2017-04-01

Full Text Available Cognitive Radio (CR is a promising and potential technique to enable secondary users (SUs or unlicenced users to exploit the unused spectrum resources effectively possessed by primary users (PUs or licenced users. The proven clustering approach is used to organize nodes in the network into the logical groups to attain energy efficiency, network scalability, and stability for improving the sensing accuracy in CR through cooperative spectrum sensing (CSS. In this paper, a distributed dynamic load balanced clustering (DDLBC algorithm is proposed. In this algorithm, each member in the cluster is to calculate the cooperative gain, residual energy, distance, and sensing cost from the neighboring clusters to perform the optimal decision. Each member in a cluster participates in selecting a cluster head (CH through cooperative gain, and residual energy that minimises network energy consumption and enhances the channel sensing. First, we form the number of clusters using the Markov decision process (MDP model to reduce the energy consumption in a network. In this algorithm, CR users effectively utilize the PUs reporting time slots of unavailability. The simulation results reveal that the clusters convergence, energy efficiency, and accuracy of channel sensing increased considerably by using the proposed algorithm.

Energy Efficient Cooperative Spectrum Sensing in Cognitive Radio Networks Using Distributed Dynamic Load Balanced Clustering Scheme

Directory of Open Access Journals (Sweden)

Muthukkumar R.

2016-07-01

Full Text Available Cognitive Radio (CR is a promising and potential technique to enable secondary users (SUs or unlicenced users to exploit the unused spectrum resources effectively possessed by primary users (PUs or licenced users. The proven clustering approach is used to organize nodes in the network into the logical groups to attain energy efficiency, network scalability, and stability for improving the sensing accuracy in CR through cooperative spectrum sensing (CSS. In this paper, a distributed dynamic load balanced clustering (DDLBC algorithm is proposed. In this algorithm, each member in the cluster is to calculate the cooperative gain, residual energy, distance, and sensing cost from the neighboring clusters to perform the optimal decision. Each member in a cluster participates in selecting a cluster head (CH through cooperative gain, and residual energy that minimises network energy consumption and enhances the channel sensing. First, we form the number of clusters using the Markov decision process (MDP model to reduce the energy consumption in a network. In this algorithm, CR users effectively utilize the PUs reporting time slots of unavailability. The simulation results reveal that the clusters convergence, energy efficiency, and accuracy of channel sensing increased considerably by using the proposed algorithm.

Extended fine structure in the K-shell photoionization spectrum of Br2

International Nuclear Information System (INIS)

Dill, D.; Dehmer, J.L.

1975-01-01

The multiple-scattering approach to molecular wavefunctions in the electronic continuum has been used recently to elucidate the structure of the shape resonance just above threshold in the K-shell photoionization spectrum of N 2 . A similar calculation for Br 2 has yielded significantly different results, i.e., there is no shape resonance; appearing instead is a single resonance in the discrete spectrum, and the photoionization spectrum is found to oscillate with appreciable amplitude throughout the spectral range investigated, from threshold to 60 Ry

Application of direct discrete method (DDM) to multigroup neutron transport problems

International Nuclear Information System (INIS)

Vosoughi, Naser; Salehi, Ali Akbar; Shahriari, Majid

2003-01-01

The Direct Discrete Method (DDM), which produced excellent results for one-group neutron transport problems, has been developed for multigroup energy. A multigroup neutron transport discrete equation has been produced for a cylindrical shape fuel element with and without associated coolant regions with two boundary conditions. The calculations are illustrated for two-group energy by graphs showing the fast and thermal fluxes. The validity of the results are tested against the results obtained by the ANISN code. (author)

Energy spectrum analysis between single and dual energy source x-ray imaging for PCB non-destructive test

Energy Technology Data Exchange (ETDEWEB)

Park, Kyeong Jin; Kim, Myung Soo; Lee, Min Ju; Kang, Dong Uk; Lee, Dae Hee; Kim, Ye Won; Kim, Chan Kyu; Kim, Hyoung Taek; Kim, Gi Yoon; Cho, Gyu Seong [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2015-08-15

Reliability of printed circuit board (PCB), which is based on high integrated circuit technology, is having been important because of development of electric and self-driving car. In order to answer these demand, automated X-ray inspection (AXI) is best solution for PCB nondestructive test. PCB is consist of plastic, copper, and, lead, which have low to high Z-number materials. By using dual energy X-ray imaging, these materials can be inspected accurately and efficiently. Dual energy X-ray imaging, that have the advantage of separating materials, however, need some solution such as energy separation method and enhancing efficiency because PCB has materials that has wide range of Z-number. In this work, we found out several things by analysis of X-ray energy spectrum. Separating between lead and combination of plastic and copper is only possible with energy range not dose. On the other hand, separating between plastic and copper is only with dose not energy range. Moreover the copper filter of high energy part of dual X-ray imaging and 50 kVp of low energy part of dual X-ray imaging is best for efficiency.

Energy spectrum analysis between single and dual energy source x-ray imaging for PCB non-destructive test

International Nuclear Information System (INIS)

Park, Kyeong Jin; Kim, Myung Soo; Lee, Min Ju; Kang, Dong Uk; Lee, Dae Hee; Kim, Ye Won; Kim, Chan Kyu; Kim, Hyoung Taek; Kim, Gi Yoon; Cho, Gyu Seong

2015-01-01

Reliability of printed circuit board (PCB), which is based on high integrated circuit technology, is having been important because of development of electric and self-driving car. In order to answer these demand, automated X-ray inspection (AXI) is best solution for PCB nondestructive test. PCB is consist of plastic, copper, and, lead, which have low to high Z-number materials. By using dual energy X-ray imaging, these materials can be inspected accurately and efficiently. Dual energy X-ray imaging, that have the advantage of separating materials, however, need some solution such as energy separation method and enhancing efficiency because PCB has materials that has wide range of Z-number. In this work, we found out several things by analysis of X-ray energy spectrum. Separating between lead and combination of plastic and copper is only possible with energy range not dose. On the other hand, separating between plastic and copper is only with dose not energy range. Moreover the copper filter of high energy part of dual X-ray imaging and 50 kVp of low energy part of dual X-ray imaging is best for efficiency

Energy Levels and Spectral Lines of Li Atoms in White Dwarf Strength Magnetic Fields

Science.gov (United States)

Zhao, L. B.

2018-04-01

A theoretical approach based on B-splines has been developed to calculate atomic structures and discrete spectra of Li atoms in a strong magnetic field typical of magnetic white dwarf stars. Energy levels are presented for 20 electronic states with the symmetries 20+, 20‑, 2(‑1)+, 2(‑1)‑, and 2(‑2)+. The magnetic field strengths involved range from 0 to 2350 MG. The wavelengths and oscillator strengths for the electric dipole transitions relevant to these magnetized atomic states are reported. The current results are compared to the limited theoretical data in the literature. A good agreement has been found for the lower energy levels, but a significant discrepancy is clearly visible for the higher energy levels. The existing discrepancies of the wavelengths and oscillator strengths are also discussed. Our investigation shows that the spectrum data of magnetized Li atoms previously published are obviously far from meeting requirements of analyzing discrete atomic spectra of magnetic white dwarfs with lithium atmospheres.

Systematic Studies of Cosmic-Ray Anisotropy and Energy Spectrum with IceCube and IceTop

Science.gov (United States)

McNally, Frank

Anisotropy in the cosmic-ray arrival direction distribution has been well documented over a large energy range, but its origin remains largely a mystery. In the TeV to PeV energy range, the galactic magnetic field thoroughly scatters cosmic rays, but anisotropy at the part-per-mille level and smaller persists, potentially carrying information about nearby cosmic-ray accelerators and the galactic magnetic field. The IceCube Neutrino Observatory was the first detector to observe anisotropy at these energies in the Southern sky. This work uses 318 billion cosmic-ray induced muon events, collected between May 2009 and May 2015 from both the in-ice component of IceCube as well as the surface component, IceTop. The observed global anisotropy features large regions of relative excess and deficit, with amplitudes on the order of 10-3. While a decomposition of the arrival direction distribution into spherical harmonics shows that most of the power is contained in the low-multipole (ℓ ≤ 4) moments, higher-multipole components are found to be statistically significant down to an angular scale of less than 10°, approaching the angular resolution of the detector. Above 100TeV, a change in the topology of the arrival direction distribution is observed, and the anisotropy is characterized by a wide relative deficit whose amplitude increases with primary energy up to at least 5PeV, the highest energies currently accessible to IceCube with sufficient event statistics. No time dependence of the large- and small-scale structures is observed in the six-year period covered by this analysis within statistical and systematic uncertainties. Analysis of the energy spectrum and composition in the PeV energy range as a function of sky position is performed with IceTop data over a five-year period using a likelihood-based reconstruction. Both the energy spectrum and the composition distribution are found to be consistent with a single source population over declination bands. This work

Neutron energy spectrum flux profile of Ghana's miniature neutron source reactor core

International Nuclear Information System (INIS)

Sogbadji, R.B.M.; Abrefah, R.G.; Ampomah-Amoako, E.; Agbemava, S.E.; Nyarko, B.J.B.

2011-01-01

Highlights: → The total neutron flux spectrum of the compact core of Ghana's miniature neutron source reactor was studied. → Using 20,484 energy grids, the thermal, slowing down and fast neutron energy regions were studied. - Abstract: The total neutron flux spectrum of the compact core of Ghana's miniature neutron source reactor was understudied using the Monte Carlo method. To create small energy groups, 20,484 energy grids were used for the three neutron energy regions: thermal, slowing down and fast. The moderator, the inner irradiation channels, the annulus beryllium reflector and the outer irradiation channels were the region monitored. The thermal neutrons recorded their highest flux in the inner irradiation channel with a peak flux of (1.2068 ± 0.0008) x 10 12 n/cm 2 s, followed by the outer irradiation channel with a peak flux of (7.9166 ± 0.0055) x 10 11 n/cm 2 s. The beryllium reflector recorded the lowest flux in the thermal region with a peak flux of (2.3288 ± 0.0004) x 10 11 n/cm 2 s. The peak values of the thermal energy range occurred in the energy range (1.8939-3.7880) x 10 -08 MeV. The inner channel again recorded the highest flux of (1.8745 ± 0.0306) x 10 09 n/cm 2 s at the lower energy end of the slowing down region between 8.2491 x 10 -01 MeV and 8.2680 x 10 -01 MeV, but was over taken by the moderator as the neutron energies increased to 2.0465 MeV. The outer irradiation channel recorded the lowest flux in this region. In the fast region, the core, where the moderator is found, the highest flux was recorded as expected, at a peak flux of (2.9110 ± 0.0198) x 10 08 n/cm 2 s at 6.961 MeV. The inner channel recorded the second highest while the outer channel and annulus beryllium recorded very low flux in this region. The flux values in this region reduce asymptotically to 20 MeV.

Crystallization in Two Dimensions and a Discrete Gauss-Bonnet Theorem

Science.gov (United States)

De Luca, L.; Friesecke, G.

2018-02-01

We show that the emerging field of discrete differential geometry can be usefully brought to bear on crystallization problems. In particular, we give a simplified proof of the Heitmann-Radin crystallization theorem (Heitmann and Radin in J Stat Phys 22(3):281-287, 1980), which concerns a system of N identical atoms in two dimensions interacting via the idealized pair potential V(r)=+∞ if r1. This is done by endowing the bond graph of a general particle configuration with a suitable notion of discrete curvature, and appealing to a discrete Gauss-Bonnet theorem (Knill in Elem Math 67:1-7, 2012) which, as its continuous cousins, relates the sum/integral of the curvature to topological invariants. This leads to an exact geometric decomposition of the Heitmann-Radin energy into (i) a combinatorial bulk term, (ii) a combinatorial perimeter, (iii) a multiple of the Euler characteristic, and (iv) a natural topological energy contribution due to defects. An analogous exact geometric decomposition is also established for soft potentials such as the Lennard-Jones potential V(r)=r^{-6}-2r^{-12}, where two additional contributions arise, (v) elastic energy and (vi) energy due to non-bonded interactions.

Wavelet Space-Scale-Decomposition Analysis of QSO's Ly$\\alpha$ Absorption Lines: Spectrum of Density Perturbations

OpenAIRE

Pando, Jesus; Fang, Li-Zhi

1995-01-01

A method for measuring the spectrum of a density field by a discrete wavelet space-scale decomposition (SSD) has been studied. We show how the power spectrum can effectively be described by the father function coefficients (FFC) of the wavelet SSD. We demonstrate that the features of the spectrum, such as the magnitude, the index of a power law, and the typical scales, can be determined with high precision by the FFC reconstructed spectrum. This method does not require the mean density, which...

Mimetic discretization methods

CERN Document Server

Castillo, Jose E

2013-01-01

To help solve physical and engineering problems, mimetic or compatible algebraic discretization methods employ discrete constructs to mimic the continuous identities and theorems found in vector calculus. Mimetic Discretization Methods focuses on the recent mimetic discretization method co-developed by the first author. Based on the Castillo-Grone operators, this simple mimetic discretization method is invariably valid for spatial dimensions no greater than three. The book also presents a numerical method for obtaining corresponding discrete operators that mimic the continuum differential and

Adaptive discrete rate and power transmission for spectrum sharing systems

KAUST Repository

Abdallah, Mohamed M.

2012-04-01

In this paper we develop a framework for optimizing the performance of the secondary link in terms of the average spectral efficiency assuming quantized channel state information (CSI) of the secondary and the secondary-to-primary interference channels available at the secondary transmitter. We consider the problem under the constraints of maximum average interference power levels at the primary receiver. We develop a sub-optimal computationally efficient iterative algorithm for finding the optimal CSI quantizers as well as the discrete power and rate employed at the cognitive transmitter for each quantized CSI level so as to maximize the average spectral efficiency. We show via analysis and simulations that the proposed algorithm converges for Rayleigh fading channels. Our numerical results give the number of bits required to sufficiently represent the CSI to achieve almost the maximum average spectral efficiency attained using full knowledge of the CSI. © 2012 IEEE.

The high-energy pulsed X-ray spectrum of Hercules X-1 as observed with OSO 8

Science.gov (United States)

Maurer, G. S.; Dennis, B. R.; Coe, M. J.; Crannell, C. J.; Dolan, J. F.; Frost, K. J.; Orwig, L. E.; Cutler, E. P.

1979-01-01

Hercules X-1 was observed from August 30 to September 10, 1977, by using the high-energy X-ray scintillation spectrometer on board the OSO 8 satellite. The observation, during which the source was monitored continually for nearly an entire ON-state, covered the energy range from 16 to 280 keV. Pulsed-flux measurements as a function of binary orbit and binary phase are presented for energies between 16 and 98 keV. The pulsed flux between 16 and 33 keV exhibited a sharp decrease following the fourth binary orbit and was consistent with zero pulsed flux thereafter. Only weak evidence was found for temporal variation in the pulsed flux between 33 and 98 keV. The pulsed spectrum has been fitted with a power law, a thermal spectrum without features, and a thermal spectrum with a superposed Gaussian centered at 55 keV. The latter fit has the smallest value of chi-square per degree of freedom, and the resulting integrated line intensity is approximately 0.0015 photon/sec per sq cm for a width of 3.1 (+9.1, -2.6) keV. This result, while of low statistical significance, agrees with the value observed by Truemper (1978) during the same ON-state.

Was The Electromagnetic Spectrum A Blackbody Spectrum In The Early Universe?

International Nuclear Information System (INIS)

Opher, M.; Opher, R.

1997-01-01

It is generally assumed that the electromagnetic spectrum in the primordial universe was a blackbody spectrum in vacuum. We derive the electromagnetic spectrum based on the fluctuation-dissipation theorem that describes the electromagnetic fluctuations in a plasma. Our description includes thermal and collisional effects in a plasma. The electromagnetic spectrum obtained differs from a blackbody spectrum in vacuum at low frequencies. In particular, concentrating on the primordial nucleosynthesis era, it has more energy than the blackbody spectrum for frequencies less than 3ω pe to 6ω pe , where ω pe is the electron plasma frequency. copyright 1997 The American Physical Society

Anyonic order parameters for discrete gauge theories on the lattice

International Nuclear Information System (INIS)

Bais, F.A.; Romers, J.C.

2009-01-01

We present a new family of gauge invariant non-local order parameters Δ α A for (non-abelian) discrete gauge theories on a Euclidean lattice, which are in one-to-one correspondence with the excitation spectrum that follows from the representation theory of the quantum double D(H) of the finite group H. These combine magnetic flux-sector labeled by a conjugacy class with an electric representation of the centralizer subgroup that commutes with the flux. In particular, cases like the trivial class for magnetic flux, or the trivial irrep for electric charge, these order parameters reduce to the familiar Wilson and the 't Hooft operators, respectively. It is pointed out that these novel operators are crucial for probing the phase structure of a class of discrete lattice models we define, using Monte Carlo simulations.

Use of orthonormal polynomials to fit energy spectrum data for water transported through membrane

International Nuclear Information System (INIS)

Bogdanova, N.; Todorova, L.

2001-01-01

A new application of our approach with orthonormal polynomials to curve fitting is given when both variables have errors. We approximate and describe data of a new effect due to change of water energy spectrum as a result of water transport in a porous membrane

A Price-Based Demand Response Scheme for Discrete Manufacturing in Smart Grids

Directory of Open Access Journals (Sweden)

Zhe Luo

2016-08-01

Full Text Available Demand response (DR is a key technique in smart grid (SG technologies for reducing energy costs and maintaining the stability of electrical grids. Since manufacturing is one of the major consumers of electrical energy, implementing DR in factory energy management systems (FEMSs provides an effective way to manage energy in manufacturing processes. Although previous studies have investigated DR applications in process manufacturing, they were not conducted for discrete manufacturing. In this study, the state-task network (STN model is implemented to represent a discrete manufacturing system. On this basis, a DR scheme with a specific DR algorithm is applied to a typical discrete manufacturing—automobile manufacturing—and operational scenarios are established for the stamping process of the automobile production line. The DR scheme determines the optimal operating points for the stamping process using mixed integer linear programming (MILP. The results show that parts of the electricity demand can be shifted from peak to off-peak periods, reducing a significant overall energy costs without degrading production processes.

Nonlinear Gravitational Waves as Dark Energy in Warped Spacetimes

Directory of Open Access Journals (Sweden)

Reinoud Jan Slagter

2017-02-01

Full Text Available We find an azimuthal-angle dependent approximate wave like solution to second order on a warped five-dimensional manifold with a self-gravitating U(1 scalar gauge field (cosmic string on the brane using the multiple-scale method. The spectrum of the several orders of approximation show maxima of the energy distribution dependent on the azimuthal-angle and the winding numbers of the subsequent orders of the scalar field. This breakup of the quantized flux quanta does not lead to instability of the asymptotic wavelike solution due to the suppression of the n-dependency in the energy momentum tensor components by the warp factor. This effect is triggered by the contribution of the five dimensional Weyl tensor on the brane. This contribution can be understood as dark energy and can trigger the self-acceleration of the universe without the need of a cosmological constant. There is a striking relation between the symmetry breaking of the Higgs field described by the winding number and the SO(2 breaking of the axially symmetric configuration into a discrete subgroup of rotations of about 180 ∘ . The discrete sequence of non-axially symmetric deviations, cancelled by the emission of gravitational waves in order to restore the SO(2 symmetry, triggers the pressure T z z for discrete values of the azimuthal-angle. There could be a possible relation between the recently discovered angle-preferences of polarization axes of quasars on large scales and our theoretical predicted angle-dependency and this could be evidence for the existence of cosmic strings. Careful comparison of this spectrum of extremal values of the first and second order φ-dependency and the distribution of the alignment of the quasar polarizations is necessary. This can be accomplished when more observational data become available. It turns out that, for late time, the vacuum 5D spacetime is conformally invariant if the warp factor fulfils the equation of a vibrating �

Effects of synchrotron radiation spectrum energy on polymethyl methacrylate photosensitivity to deep x-ray lithography

International Nuclear Information System (INIS)

Mekaru, Harutaka; Utsumi, Yuichi; Hattori, Tadashi

2003-01-01

Since X-ray lithography requires a high photon flux to achieve deep resist exposure, a synchrotron radiation beam, which is not monochromatized, is generally used as a light source. If the synchrotron radiation beam is monochromatized, photon flux will decrease rapidly. Because of this reason, the wavelength dependence of the resist sensitivity has not been investigated for deep X-ray lithography. Measuring the spectrum of a white beam with a Si solid-state detector (SSD) is difficult because a white beam has a high intensity and an SSD has a high sensitivity. We were able to measure the spectrum and the photocurrent of a white beam from a beam line used for deep X-ray lithography by keeping the ring current below 0.05 mA. We evaluated the characteristics of the output beam based on the measured spectrum and photocurrent, and used them to investigate the relationship between the total exposure energy and the dose-processing depth with polymethyl methacrylate (PMMA). We found that it is possible to guess the processing depth of PMMA from the total exposure energy in deep X-ray lithography. (author)

Analysis of a gamma-ray spectrum by using a standard spectrum

International Nuclear Information System (INIS)

Tasaka, Kanji

1975-06-01

The standard spectrum method has been extended to take into account the energy dependence of a standard spectrum. The method analyses the observed gamma-ray spectrum by the least-square method, using an interpolated standard spectrum for expressing the line shape and a linear function for the background continuum. The interpolated standard spectrum is defined for each fitting interval by interpolating several standard spectra, which are derived directly from the observed spectra of single photopeaks each corresponding to the incident monochromatic gamma-rays by subtracting the background and smoothing the data. (author)

Understanding the spectrum of domestic energy consumption: Empirical evidence from France

International Nuclear Information System (INIS)

Belaïd, Fateh

2016-01-01

This article focuses on residential energy consumption in France. Using a bottom-up statistical approach, this analysis explores determinants of household energy consumption using data from the most recent National Housing Survey. The primary objective is to tease out the impacts of various factors on the domestic energy consumption spectrum across different population groups. The aim of this approach is to neutralize conventional factors affecting energy consumption (age of house, total area, etc.) to finely analyze the impact of other determinants including those relating to household characteristics and other control variables. First, we define homogeneous consumption groups of households by using multivariate statistical techniques, namely the Multiple Correspondence Analysis and Ascending Hierarchical Classification. Second, we use standard OLS regression to explore the effects of various factors on domestic energy consumption among homogeneous groups of households. This multivariate analysis exercise has led us to identify four main consumption typologies. Results revealed that energy prices were the most important factors determining domestic energy consumption. In addition, this study showed that occupant characteristics significantly affect domestic energy use. Results of this research call for combine all efforts, multiple strategies and smart policies, to incorporate household and consumption behaviors in managing domestic energy consumption. - Highlights: •Survey data of 36,000 occupiers from France is analyzed. •Bottom-up statistical approach is used to analyze domestic energy consumption. •Occupant characteristics significantly affect domestic energy use. •The impact of households attributes varies markedly across consumption groups.

Discrete hierarchical organization of social group sizes.

Science.gov (United States)

Zhou, W-X; Sornette, D; Hill, R A; Dunbar, R I M

2005-02-22

The 'social brain hypothesis' for the evolution of large brains in primates has led to evidence for the coevolution of neocortical size and social group sizes, suggesting that there is a cognitive constraint on group size that depends, in some way, on the volume of neural material available for processing and synthesizing information on social relationships. More recently, work on both human and non-human primates has suggested that social groups are often hierarchically structured. We combine data on human grouping patterns in a comprehensive and systematic study. Using fractal analysis, we identify, with high statistical confidence, a discrete hierarchy of group sizes with a preferred scaling ratio close to three: rather than a single or a continuous spectrum of group sizes, humans spontaneously form groups of preferred sizes organized in a geometrical series approximating 3-5, 9-15, 30-45, etc. Such discrete scale invariance could be related to that identified in signatures of herding behaviour in financial markets and might reflect a hierarchical processing of social nearness by human brains.

First measurement of the VESUVIO neutron spectrum in the 30-80 MeV energy range using a Proton Recoil Telescope technique

Science.gov (United States)

Cazzaniga, C.; Tardocchi, M.; Croci, G.; Frost, C.; Giacomelli, L.; Grosso, G.; Hjalmarsson, A.; Rebai, M.; Rhodes, N. J.; Schooneveld, E. M.; Gorini, G.

2013-11-01

Measurements of the fast neutron energy spectrum at the ISIS spallation source are reported. The measurements were performed with a Proton Recoil Telescope consisting of a thin plastic foil placed in the neutron beam and two scintillator detectors. Results in the neutron energy range 30 MeV < En < 80 MeV are in good agreement with Monte Carlo simulations of the neutron spectrum.

Is the primary energy spectrum around the knee a statistical game?

International Nuclear Information System (INIS)

Kempa, J.

2001-01-01

The present state of research of the shape of the energy spectrum of primary cosmic ray nuclei and the chemical composition in the region of the so-called, knee, and beyond is highly unsatisfactory. It was not very successful when using extensive air showers. In the present paper an attempt is made to explain what is the cause of such a situation. The experimental results as to which there is no doubt that they were wrongly interpreted, will be indicated

DOMINO, Coupling of Discrete Ordinate Program DOT with Monte-Carlo Program MORSE

International Nuclear Information System (INIS)

1974-01-01

1 - Nature of physical problem solved: DOMINO is a general purpose code for coupling discrete ordinates and Monte Carlo radiation transport calculations. 2 - Method of solution: DOMINO transforms the angular flux as a function of energy group, mesh interval and discrete angle into current and subsequently into normalized probability distributions. 3 - Restrictions on the complexity of the problem: The discrete ordinates calculation is limited to an r-z geometry

Continuous versus discrete structures II -- Discrete Hamiltonian systems and Helmholtz conditions

OpenAIRE

Cresson, Jacky; Pierret, Frédéric

2015-01-01

We define discrete Hamiltonian systems in the framework of discrete embeddings. An explicit comparison with previous attempts is given. We then solve the discrete Helmholtz's inverse problem for the discrete calculus of variation in the Hamiltonian setting. Several applications are discussed.

Spectrum and energy levels of six-times-ionized molybdenum (Mo VII)

International Nuclear Information System (INIS)

Reader, J.

1990-01-01

The spectrum of the kryptonlike ion Mo VII was observed from 140 to 2274 A with sliding-spark discharges on 10.7-m normal- and grazing-incidence spectrographs. Experimental energies were determined for all levels of the 4s 2 4p 6 , 4s 2 4p 5 4d, 4f, 5s, 5p, 5d, 5f, 5g, and 4s4p 6 4d configurations. A few levels of the 4s 2 4p 4 4d 2 configuration were also found. A total of 399 lines were classified as transitions between 86 observed levels. The observed configurations were theoretically interpreted. The energy parameters determined by least-squares fits to the observed levels are compared with Hartree--Fock calculations. A revised value of the ionization energy was obtained by using the energy of the 4p 5 5g configuration together with an isoelectronically extrapolated value of the effective quantum number n(5g). The adopted limit is 1 013 340±200 cm -1 (125.64±0.02 eV)

The energy spectrum of electromagnetic normal modes in dissipative media: modes between two metal half spaces

International Nuclear Information System (INIS)

Sernelius, Bo E

2008-01-01

The energy spectrum of electromagnetic normal modes plays a central role in the theory of the van der Waals and Casimir interaction. Here we study the modes in connection with the van der Waals interaction between two metal half spaces. Neglecting dissipation leads to distinct normal modes with real-valued frequencies. Including dissipation seems to have the effect that these distinct modes move away from the real axis into the complex frequency plane. The summation of the zero-point energies of these modes render a complex-valued result. Using the contour integration, resulting from the use of the generalized argument principle, gives a real-valued and different result. We resolve this contradiction and show that the spectrum of true normal modes forms a continuum with real frequencies

Search for the end of the cosmic ray energy spectrum

International Nuclear Information System (INIS)

Linsley, John

1998-01-01

The title I was asked to speak about expresses an idea that occurred rather recently in the history of cosmic ray studies. I argue that the idea of a possible end of the cosmic ray energy spectrum came into being after a sequence of three rapid advances in knowledge which I describe, calling them 'breakthroughs'. I suggest that the present workshop be regarded as a step toward a fourth breakthrough. I argue that this may occur through application of the Space Airwatch concept--the earth atmosphere as target and signal generator--as embodied in the NASA OWL project

Discrete Mathematics

DEFF Research Database (Denmark)

Sørensen, John Aasted

2011-01-01

; construct a finite state machine for a given application. Apply these concepts to new problems. The teaching in Discrete Mathematics is a combination of sessions with lectures and students solving problems, either manually or by using Matlab. Furthermore a selection of projects must be solved and handed...... to accomplish the following: -Understand and apply formal representations in discrete mathematics. -Understand and apply formal representations in problems within discrete mathematics. -Understand methods for solving problems in discrete mathematics. -Apply methods for solving problems in discrete mathematics...... to new problems. Relations and functions: Define a product set; define and apply equivalence relations; construct and apply functions. Apply these concepts to new problems. Natural numbers and induction: Define the natural numbers; apply the principle of induction to verify a selection of properties...

Digital Discretion

DEFF Research Database (Denmark)

Busch, Peter Andre; Zinner Henriksen, Helle

2018-01-01

discretion is suggested to reduce this footprint by influencing or replacing their discretionary practices using ICT. What is less researched is whether digital discretion can cause changes in public policy outcomes, and under what conditions such changes can occur. Using the concept of public service values......This study reviews 44 peer-reviewed articles on digital discretion published in the period from 1998 to January 2017. Street-level bureaucrats have traditionally had a wide ability to exercise discretion stirring debate since they can add their personal footprint on public policies. Digital......, we suggest that digital discretion can strengthen ethical and democratic values but weaken professional and relational values. Furthermore, we conclude that contextual factors such as considerations made by policy makers on the macro-level and the degree of professionalization of street...

On the energy spectrum of the Bethe-Salpeter equation; Ob ehnergeticheskom spektre uravneniya Bete-Solpitera

Energy Technology Data Exchange (ETDEWEB)

Dorkin, S M [Dal` nevostochnyj Gosudarstvennyj Univ., Vladivostok (Russian Federation); Kaptar` , L P; Semikh, S S [Joint Inst. for Nuclear Research, Dubna (Russian Federation). Lab. of Theoretical Physics

1997-12-31

The problem of calculating the energy spectrum of a two-fermion bound state within the Bethe-Salpeter formalism is discussed. An expansion of the kernel of the spinor-spinor Bethe-Salpeter equation in the ladder approximation is found in terms of a bi-orthogonal basis of the generalized Gilbert-Schmidt series for symmetric equations of the Fredholm type. According to this expansion, a new method of solving the Bethe-Salpeter equation and finding the mass spectrum is proposed. Methodological result of numerical solutions of equations with scalar interaction is presented. (author). 20 refs., 3 figs.

Measuring extensive air showers with Cherenkov light detectors of the Yakutsk array: the energy spectrum of cosmic rays

International Nuclear Information System (INIS)

Ivanov, A A; Knurenko, S P; Sleptsov, I Ye

2009-01-01

The energy spectrum of cosmic rays in the range E∼10 15 eV to 6x10 19 eV is studied in this paper using air Cherenkov light detectors of the Yakutsk array. The total flux of photons produced by the relativistic electrons (including positrons as well, hereafter) of extensive air showers in the atmosphere is used as an energy estimator of the primary particle initiating a shower. The resultant differential flux of cosmic rays exhibits, in agreement with previous measurements, a knee and ankle feature at energies of 3x10 15 and ∼10 19 eV, respectively. A comparison of observational data with simulations is made in the knee and ankle regions in order to choose the models of galactic and extragalactic components of cosmic rays that describe well the energy spectrum measured.

Measuring extensive air showers with Cherenkov light detectors of the Yakutsk array: the energy spectrum of cosmic rays

Energy Technology Data Exchange (ETDEWEB)

Ivanov, A A; Knurenko, S P; Sleptsov, I Ye [Shafer Institute for Cosmophysical Research and Aeronomy, Yakutsk 677980 (Russian Federation)], E-mail: ivanov@ikfia.ysn.ru

2009-06-15

The energy spectrum of cosmic rays in the range E{approx}10{sup 15} eV to 6x10{sup 19} eV is studied in this paper using air Cherenkov light detectors of the Yakutsk array. The total flux of photons produced by the relativistic electrons (including positrons as well, hereafter) of extensive air showers in the atmosphere is used as an energy estimator of the primary particle initiating a shower. The resultant differential flux of cosmic rays exhibits, in agreement with previous measurements, a knee and ankle feature at energies of 3x10{sup 15} and {approx}10{sup 19} eV, respectively. A comparison of observational data with simulations is made in the knee and ankle regions in order to choose the models of galactic and extragalactic components of cosmic rays that describe well the energy spectrum measured.

Free energy of RNA-counterion interactions in a tight-binding model computed by a discrete space mapping

International Nuclear Information System (INIS)

Henke, Paul S.; Mak, Chi H.

2014-01-01

The thermodynamic stability of a folded RNA is intricately tied to the counterions and the free energy of this interaction must be accounted for in any realistic RNA simulations. Extending a tight-binding model published previously, in this paper we investigate the fundamental structure of charges arising from the interaction between small functional RNA molecules and divalent ions such as Mg 2+ that are especially conducive to stabilizing folded conformations. The characteristic nature of these charges is utilized to construct a discretely connected energy landscape that is then traversed via a novel application of a deterministic graph search technique. This search method can be incorporated into larger simulations of small RNA molecules and provides a fast and accurate way to calculate the free energy arising from the interactions between an RNA and divalent counterions. The utility of this algorithm is demonstrated within a fully atomistic Monte Carlo simulation of the P4-P6 domain of the Tetrahymena group I intron, in which it is shown that the counterion-mediated free energy conclusively directs folding into a compact structure

Free energy of RNA-counterion interactions in a tight-binding model computed by a discrete space mapping

Energy Technology Data Exchange (ETDEWEB)

Henke, Paul S. [Department of Chemistry, University of Southern California, Los Angeles, California 90089 (United States); Mak, Chi H., E-mail: cmak@usc.edu [Department of Chemistry, University of Southern California, Los Angeles, California 90089 (United States); Center of Applied Mathematical Sciences, University of Southern California, Los Angeles, California 90089 (United States)

2014-08-14

The thermodynamic stability of a folded RNA is intricately tied to the counterions and the free energy of this interaction must be accounted for in any realistic RNA simulations. Extending a tight-binding model published previously, in this paper we investigate the fundamental structure of charges arising from the interaction between small functional RNA molecules and divalent ions such as Mg{sup 2+} that are especially conducive to stabilizing folded conformations. The characteristic nature of these charges is utilized to construct a discretely connected energy landscape that is then traversed via a novel application of a deterministic graph search technique. This search method can be incorporated into larger simulations of small RNA molecules and provides a fast and accurate way to calculate the free energy arising from the interactions between an RNA and divalent counterions. The utility of this algorithm is demonstrated within a fully atomistic Monte Carlo simulation of the P4-P6 domain of the Tetrahymena group I intron, in which it is shown that the counterion-mediated free energy conclusively directs folding into a compact structure.

Distribution for fermionic discrete lattice gas within the canonical ensemble

International Nuclear Information System (INIS)

Kutner, R.; Barszczak, T.

1991-01-01

The distinct deviations from the Fermi-Dirac statistics ascertained recently at low temperatures for a one-dimensional, spinless fermionic discrete lattice gas with conserved number of noninteracting particles hopping on the nondegenerated, well-separated single-particle energy levels are studied in numerical and theoretical terms. The generalized distribution is derived in the form n(h) = {Y h exp[(var-epsilon h -μ)β]+1} -1 valid even in the thermodynamic limit, when the discreteness of the energy levels is kept. This distribution demonstrates good agreement with the data obtained numerically both by the canonical partition-function technique and by Monte Carlo simulation

Two-dimensional angular energy spectrum of electrons accelerated by the ultra-short relativistic laser pulse

Energy Technology Data Exchange (ETDEWEB)

Borovskiy, A. V. [Department of Computer Science and Cybernetics, Baikal State University of Economics and Law, 11 Lenin Street, Irkutsk 664003 (Russian Federation); Galkin, A. L. [Coherent and Nonlinear Optics Department, A.M. Prokhorov General Physics Institute of the RAS, 38 Vavilov Street, Moscow 119991 (Russian Federation); Department of Physics of MBF, Pirogov Russian National Research Medical University, 1 Ostrovitianov Street, Moscow 117997 (Russian Federation); Kalashnikov, M. P., E-mail: galkin@kapella.gpi.ru [Max-Born-Institute for Nonlinear Optics and Short-Time Spectroscopy, 2a Max-Born-Strasse, Berlin 12489 (Germany)

2015-04-15

The new method of calculating energy spectra of accelerated electrons, based on the parameterization by their initial coordinates, is proposed. The energy spectra of electrons accelerated by Gaussian ultra-short relativistic laser pulse at a selected angle to the axis of the optical system focusing the laser pulse in a low density gas are theoretically calculated. The two-peak structure of the electron energy spectrum is obtained. Discussed are the reasons for its appearance as well as an applicability of other models of the laser field.

Turbulent kinetic energy spectrum in very anisothermal flows

International Nuclear Information System (INIS)

Serra, Sylvain; Toutant, Adrien; Bataille, Françoise; Zhou, Ye

2012-01-01

In this Letter, we find that the Kolmogorov scaling law is no longer valid when the flow is submitted to strong dilatational effects caused by high temperature gradients. As a result, in addition to the nonlinear time scale, there is a much shorter “temperature gradients” time scale. We propose a model that estimates the time scale of the triple decorrelation incorporating the influences of the temperature gradient. The model agrees with the results from the thermal large-eddy simulations of different Reynolds numbers and temperature gradients. This Letter provides a better understanding of the very anisothermal turbulent flow. -- Highlights: ► Turbulent flows subject to high temperature gradients are considered. ► The new “temperature gradients” time scale is determined. ► A generalized energy spectrum is developed to incorporate the effects of temperature gradient.

Spinless Salpeter equation: Laguerre bounds on energy levels

International Nuclear Information System (INIS)

Lucha, W.; Schoeberl, F.F.

1996-08-01

The spinless Salpeter equation may be considered either as a standard approximation to the Bethe-Salpeter formalism, designed for the description of bound states within a relativistic quantum field theory, or as the most simple, to a certain extent relativistic generalization of the customary non relativistic Schroedinger formalism. Because of the presence of the rather difficult-to-handle square-root operator of the relativistic kinetic energy in the corresponding Hamiltonian, very frequently the corresponding (discrete) spectrum of energy eigenvalues cannot be determined analytically. Therefore, we show how to calculate, by some clever choice of basis vectors in the Hilbert space of solutions, for the rather large class of power-law potentials, at least (sometimes excellent) upper bounds on these energy eigenvalues, for the lowest-lying levels this even analytically. (author)

Control of a 420 KN Discrete Displacement Cylinder Drive for the Wavestar Wave Energy Converter

DEFF Research Database (Denmark)

Hansen, Rico H.; Andersen, Torben Ole; Pedersen, Henrik C.

2014-01-01

absorbers. The system is implemented using multi-chambered cylinders, where the different chambers may be switched between three pressure lines using a manifold with fast on/off valves. Resultantly, a Discrete Displacement Cylinder (DDC) is obtained, where force control is implemented by shifting between...... different area/pressure combinations. Currently, a 420 kN DDC prototype has been implemented and tested at the newly commissioned full size wave energy testbench at Aalborg University. The initial design and control of the DDC had poorly damped switching transients. These issues treated in this paper....... This leads to a new control, which gives a smooth operating DDC, while meeting the requirements to the efficiency of the drive....

Energy level diagrams for black hole orbits

Science.gov (United States)

Levin, Janna

2009-12-01

A spinning black hole with a much smaller black hole companion forms a fundamental gravitational system, like a colossal classical analog to an atom. In an appealing if imperfect analogy with atomic physics, this gravitational atom can be understood through a discrete spectrum of periodic orbits. Exploiting a correspondence between the set of periodic orbits and the set of rational numbers, we are able to construct periodic tables of orbits and energy level diagrams of the accessible states around black holes. We also present a closed-form expression for the rational q, thereby quantifying zoom-whirl behavior in terms of spin, energy and angular momentum. The black hole atom is not just a theoretical construct, but corresponds to extant astrophysical systems detectable by future gravitational wave observatories.

Energy level diagrams for black hole orbits

International Nuclear Information System (INIS)

Levin, Janna

2009-01-01

A spinning black hole with a much smaller black hole companion forms a fundamental gravitational system, like a colossal classical analog to an atom. In an appealing if imperfect analogy with atomic physics, this gravitational atom can be understood through a discrete spectrum of periodic orbits. Exploiting a correspondence between the set of periodic orbits and the set of rational numbers, we are able to construct periodic tables of orbits and energy level diagrams of the accessible states around black holes. We also present a closed-form expression for the rational q, thereby quantifying zoom-whirl behavior in terms of spin, energy and angular momentum. The black hole atom is not just a theoretical construct, but corresponds to extant astrophysical systems detectable by future gravitational wave observatories.

A particular inverse problem for Schroedinger discrete equation in two and higher dimensions under apriori information of wave functions

International Nuclear Information System (INIS)

Pavlus, M.

1997-01-01

The entire potential and the rest of wave functions are determined in parallelepiped domain if the entire discrete spectrum and the apriori information about the wave functions on one side of parallelepiped are given. Formulation for solving the Schroedinger discrete equation in two and higher dimensions is proposed and new formulas are derived for their solution. Two examples for a 2D case and one example for a 3D case are demonstrated

The choice of optimal Discrete Interaction Approximation to the kinetic integral for ocean waves

Directory of Open Access Journals (Sweden)

V. G. Polnikov

2003-01-01

Full Text Available A lot of discrete configurations for the four-wave nonlinear interaction processes have been calculated and tested by the method proposed earlier in the frame of the concept of Fast Discrete Interaction Approximation to the Hasselmann's kinetic integral (Polnikov and Farina, 2002. It was found that there are several simple configurations, which are more efficient than the one proposed originally in Hasselmann et al. (1985. Finally, the optimal multiple Discrete Interaction Approximation (DIA to the kinetic integral for deep-water waves was found. Wave spectrum features have been intercompared for a number of different configurations of DIA, applied to a long-time solution of kinetic equation. On the basis of this intercomparison the better efficiency of the configurations proposed was confirmed. Certain recommendations were given for implementation of new approximations to the wave forecast practice.

Spectrum monitoring procedures and techniques

Science.gov (United States)

1990-07-01

The first step towards operating an emitter on a test range is to contact the local frequency manager to establish a schedule. Since restricted radio frequency bands and operations are different at each test range location, most testing is accomplished by sharing the spectrum available with all range users. The telemetry bands in particular require spectrum activity scheduling. The objective is to resolve scheduling conflicts prior to operations. When two programs or projects request to use the same spectrum, their activity can be separated by quard bands, discrete frequencies, time, or operating locations (terrain masking). Priorities assigned to each program usually dictate which program will be scheduled first; however, use of priorities to schedule activities should be avoided and only considered as a last resort. When a scheduling conflict cannot be resolved using these techniques, it is brought to the attention of the responsible program managers. When scheduling activities involve other federal or nonfederal agencies, it is in the best interest of program managers to be as flexible as possible.

Analysis of alpha spectrum instrumental errors accounting for the low energy part of semiconductor detector response function

International Nuclear Information System (INIS)

Gurbich, A.F.

1981-01-01

A technique for processing of instrumental spectrum of charged particles permitting to take account of a low-energy part of spectrometer line shape, to improve accuracy and to estimate detection efficiency is stated on the example of 226 Ra alpha spectrum. The results obtained show that relative intensities of alpha lines within the limits of statistical errors coincide with the known values, line ''tails'' constituting to 3% of total area of the line. Taking account of ''the line tail'' results in shift of centers of peak gravity by 10-20 keV. So low-energy part of the alpha spectrometer line, which is usually not taken account during spectra processing, markedly affect the results [ru

Contribution from individual nearby sources to the spectrum of high-energy cosmic-ray electrons

International Nuclear Information System (INIS)

Sedrati, R.; Attallah, R.

2014-01-01

In the last few years, very important data on high-energy cosmic-ray electrons and positrons from high-precision space-born and ground-based experiments have attracted a great deal of interest. These particles represent a unique probe for studying local comic-ray accelerators because they lose energy very rapidly. These energy losses reduce the lifetime so drastically that high-energy cosmic-ray electrons can attain the Earth only from rather local astrophysical sources. This work aims at calculating, by means of Monte Carlo simulation, the contribution from some known nearby astrophysical sources to the cosmic-ray electron/positron spectra at high energy (≥10GeV). The background to the electron energy spectrum from distant sources is determined with the help of the GALPROP code. The obtained numerical results are compared with a set of experimental data

Contribution from individual nearby sources to the spectrum of high-energy cosmic-ray electrons

Energy Technology Data Exchange (ETDEWEB)

Sedrati, R., E-mail: rafik.sedrati@univ-annaba.org; Attallah, R.

2014-04-01

In the last few years, very important data on high-energy cosmic-ray electrons and positrons from high-precision space-born and ground-based experiments have attracted a great deal of interest. These particles represent a unique probe for studying local comic-ray accelerators because they lose energy very rapidly. These energy losses reduce the lifetime so drastically that high-energy cosmic-ray electrons can attain the Earth only from rather local astrophysical sources. This work aims at calculating, by means of Monte Carlo simulation, the contribution from some known nearby astrophysical sources to the cosmic-ray electron/positron spectra at high energy (≥10GeV). The background to the electron energy spectrum from distant sources is determined with the help of the GALPROP code. The obtained numerical results are compared with a set of experimental data.

Quantum-gravity fluctuations and the black-hole temperature

Energy Technology Data Exchange (ETDEWEB)

Hod, Shahar [The Ruppin Academic Center, Emeq Hefer (Israel); The Hadassah Institute, Jerusalem (Israel)

2015-05-15

Bekenstein has put forward the idea that, in a quantum theory of gravity, a black hole should have a discrete energy spectrum with concomitant discrete line emission. The quantized black-hole radiation spectrum is expected to be very different from Hawking's semi-classical prediction of a thermal black-hole radiation spectrum. One naturally wonders: Is it possible to reconcile the discrete quantum spectrum suggested by Bekenstein with the continuous semi-classical spectrum suggested by Hawking? In order to address this fundamental question, in this essay we shall consider the zero-point quantum-gravity fluctuations of the black-hole spacetime. In a quantum theory of gravity, these spacetime fluctuations are closely related to the characteristic gravitational resonances of the corresponding black-hole spacetime. Assuming that the energy of the black-hole radiation stems from these zero-point quantum-gravity fluctuations of the black-hole spacetime, we derive the effective temperature of the quantized black-hole radiation spectrum. Remarkably, it is shown that this characteristic temperature of the discrete (quantized) black-hole radiation agrees with the well-known Hawking temperature of the continuous (semi-classical) black-hole spectrum. (orig.)

Quantum-gravity fluctuations and the black-hole temperature

International Nuclear Information System (INIS)

Hod, Shahar

2015-01-01

Bekenstein has put forward the idea that, in a quantum theory of gravity, a black hole should have a discrete energy spectrum with concomitant discrete line emission. The quantized black-hole radiation spectrum is expected to be very different from Hawking's semi-classical prediction of a thermal black-hole radiation spectrum. One naturally wonders: Is it possible to reconcile the discrete quantum spectrum suggested by Bekenstein with the continuous semi-classical spectrum suggested by Hawking? In order to address this fundamental question, in this essay we shall consider the zero-point quantum-gravity fluctuations of the black-hole spacetime. In a quantum theory of gravity, these spacetime fluctuations are closely related to the characteristic gravitational resonances of the corresponding black-hole spacetime. Assuming that the energy of the black-hole radiation stems from these zero-point quantum-gravity fluctuations of the black-hole spacetime, we derive the effective temperature of the quantized black-hole radiation spectrum. Remarkably, it is shown that this characteristic temperature of the discrete (quantized) black-hole radiation agrees with the well-known Hawking temperature of the continuous (semi-classical) black-hole spectrum. (orig.)

First measurement of the VESUVIO neutron spectrum in the 30–80 MeV energy range using a Proton Recoil Telescope technique

International Nuclear Information System (INIS)

Cazzaniga, C; Tardocchi, M; Croci, G; Grosso, G; Rebai, M; Gorini, G; Frost, C; Rhodes, N J; Schooneveld, E M; Giacomelli, L; Hjalmarsson, A

2013-01-01

Measurements of the fast neutron energy spectrum at the ISIS spallation source are reported. The measurements were performed with a Proton Recoil Telescope consisting of a thin plastic foil placed in the neutron beam and two scintillator detectors. Results in the neutron energy range 30 MeV n < 80 MeV are in good agreement with Monte Carlo simulations of the neutron spectrum

Thermodynamic properties of a solid exhibiting the energy spectrum given by the logistic map

International Nuclear Information System (INIS)

Curado, E.M.F.

2000-05-01

We show that the infinite-dimensional representation of the recently introduced Logistic algebra can be interpreted as a non-trivial generalization of the Heisenberg or oscillator algebra. This allows to construct a quantum Hamiltonian having the energy energy spectrum given by the logistic map. We analyze the Hamiltonian of a solid whose collective modes of vibrations are described by this generalized oscillator and compute the thermodynamic properties of the model in the two-cycle and γ3.6785 chaotic region of the logistic map. (author)

Time resolved energy spectrum of the axial ion beam generated in plasma focus discharges

International Nuclear Information System (INIS)

Bostick, W.H.; Kilic, H.; Nardi, V.; Powell, C.W.

1993-01-01

The energy spectrum of the deuteron beam along the electrode axis (0 (degree) ) in a plasma focus discharge has been determined with a time of flight (TOF) method and with a differential filter method in the ion energy interval E = 0.3-9 MeV. The ion TOF method is applied to single-ion pulse events with an ion emission time t(E) that is only weakly dependent on the ion energy E for E > 0.3 MeV. The correlation of the ion beam intensity with the filling pressure, the neutron yield and the hard X-ray intensity is also reported. (author). 11 refs, 10 figs

Energy/bandwidth-Saving Cooperative Spectrum Sensing for Two-hopWRAN

Directory of Open Access Journals (Sweden)

Ming-Tuo Zhou

2014-07-01

Full Text Available A two-hop wireless regional area network (WRAN providing monitoring services operating in Television White Space (TVWS, i.e., IEEE P802.22b, may employ a great number of subscriber customer-premises equipments (S-CPEs possibly without mains power supply, leading to requirement of cost-effective and power-saving design. This paper proposes a framework of cooperative spectrum sensing (CSS and an energy/bandwidth saving CSS scheme to P802.22b. In each round of sensing, S-CPEs with SNRs lower than a predefined threshold are excluded from reporting sensing results. Numerical results show that the fused missed-detection probability and false alarmprobability could remainmeeting sensing requirements, and the overall fused error probability changes very little. With 10 S-CPEs, it is possible to save more than 40% of the energy/bandwidth on a Rayleigh channel. The principle proposed can apply to other advanced sensing technologies capable of detecting primary signals with low average SNR.

State transformations and Hamiltonian structures for optimal control in discrete systems

Science.gov (United States)

Sieniutycz, S.

2006-04-01

Preserving usual definition of Hamiltonian H as the scalar product of rates and generalized momenta we investigate two basic classes of discrete optimal control processes governed by the difference rather than differential equations for the state transformation. The first class, linear in the time interval θ, secures the constancy of optimal H and satisfies a discrete Hamilton-Jacobi equation. The second class, nonlinear in θ, does not assure the constancy of optimal H and satisfies only a relationship that may be regarded as an equation of Hamilton-Jacobi type. The basic question asked is if and when Hamilton's canonical structures emerge in optimal discrete systems. For a constrained discrete control, general optimization algorithms are derived that constitute powerful theoretical and computational tools when evaluating extremum properties of constrained physical systems. The mathematical basis is Bellman's method of dynamic programming (DP) and its extension in the form of the so-called Carathéodory-Boltyanski (CB) stage optimality criterion which allows a variation of the terminal state that is otherwise fixed in Bellman's method. For systems with unconstrained intervals of the holdup time θ two powerful optimization algorithms are obtained: an unconventional discrete algorithm with a constant H and its counterpart for models nonlinear in θ. We also present the time-interval-constrained extension of the second algorithm. The results are general; namely, one arrives at: discrete canonical equations of Hamilton, maximum principles, and (at the continuous limit of processes with free intervals of time) the classical Hamilton-Jacobi theory, along with basic results of variational calculus. A vast spectrum of applications and an example are briefly discussed with particular attention paid to models nonlinear in the time interval θ.

Improved spatial resolution and lower-dose pediatric CT imaging: a feasibility study to evaluate narrowing the X-ray photon energy spectrum

Energy Technology Data Exchange (ETDEWEB)

Benz, Mark G. [Safer Pediatric Imaging and Engineering Horizons International, Lincoln, VT (United States); Benz, Matthew W. [Southboro Medical Group, Southboro, MA (United States); Birnbaum, Steven B. [Dartmouth Hitchcock Clinic Manchester, Department of Radiology, Manchester, NH (United States); Chason, Eric; Sheldon, Brian W. [Brown University, Division of Engineering, Materials Science and Engineering Program, Providence, RI (United States); McGuire, Dale [R and D Manager, C and G Technologies Inc., Jeffersonville, IN (United States)

2014-08-15

This feasibility study has shown that improved spatial resolution and reduced radiation dose can be achieved in pediatric CT by narrowing the X-ray photon energy spectrum. This is done by placing a hafnium filter between the X-ray generator and a pediatric abdominal phantom. A CT system manufactured in 1999 that was in the process of being remanufactured was used as the platform for this study. This system had the advantage of easy access to the X-ray generator for modifications to change the X-ray photon energy spectrum; it also had the disadvantage of not employing the latest post-imaging noise reduction iterative reconstruction technology. Because we observed improvements after changing the X-ray photon energy spectrum, we recommend a future study combining this change with an optimized iterative reconstruction noise reduction technique. (orig.)

The energy spectrum of delayed neutrons from thermal neutron induced fission of 235U and its analytical approximation

International Nuclear Information System (INIS)

Doroshenko, A.Yu.; Tarasko, M.Z.; Piksaikin, V.M.

2002-01-01

The energy spectrum of the delayed neutrons is the poorest known of all input data required in the calculation of the effective delayed neutron fractions. In addition to delayed neutron spectra based on the aggregate spectrum measurements there are two different approaches for deriving the delayed neutron energy spectra. Both of them are based on the data related to the delayed neutron spectra from individual precursors of delayed neutrons. In present work these two different data sets were compared with the help of an approximation by gamma-function. The choice of this approximation function instead of the Maxwellian or evaporation type of distribution is substantiated. (author)

Effect of photon energy spectrum on dosimetric parameters of brachytherapy sources.

Science.gov (United States)

Ghorbani, Mahdi; Mehrpouyan, Mohammad; Davenport, David; Ahmadi Moghaddas, Toktam

2016-06-01

The aim of this study is to quantify the influence of the photon energy spectrum of brachytherapy sources on task group No. 43 (TG-43) dosimetric parameters. Different photon spectra are used for a specific radionuclide in Monte Carlo simulations of brachytherapy sources. MCNPX code was used to simulate 125I, 103Pd, 169Yb, and 192Ir brachytherapy sources. Air kerma strength per activity, dose rate constant, radial dose function, and two dimensional (2D) anisotropy functions were calculated and isodose curves were plotted for three different photon energy spectra. The references for photon energy spectra were: published papers, Lawrence Berkeley National Laboratory (LBNL), and National Nuclear Data Center (NNDC). The data calculated by these photon energy spectra were compared. Dose rate constant values showed a maximum difference of 24.07% for 103Pd source with different photon energy spectra. Radial dose function values based on different spectra were relatively the same. 2D anisotropy function values showed minor differences in most of distances and angles. There was not any detectable difference between the isodose contours. Dosimetric parameters obtained with different photon spectra were relatively the same, however it is suggested that more accurate and updated photon energy spectra be used in Monte Carlo simulations. This would allow for calculation of reliable dosimetric data for source modeling and calculation in brachytherapy treatment planning systems.

Effects of virtual isobar admixtures on the low-energy spectrum of a complex nucleus - model calculations for 12C

International Nuclear Information System (INIS)

Grecksch, E.

1978-01-01

On the basis of a detailed analysis of the excitation spectrum of a complex nucleus in the framework of the conventional shell model theory, the paper extends this concept by adding nucleonic degrees of freedom (isobars) and by model investigations and a realistic assessment of their effects on the excited states of the low-energy spectrum. (AH) [de

Learning Frameworks for Cooperative Spectrum Sensing and Energy-Efficient Data Protection in Cognitive Radio Networks

Directory of Open Access Journals (Sweden)

Vinh Quang Do

2018-05-01

Full Text Available This paper studies learning frameworks for energy-efficient data communications in an energy-harvesting cognitive radio network in which secondary users (SUs harvest energy from solar power while opportunistically accessing a licensed channel for data transmission. The SUs perform spectrum sensing individually, and send local decisions about the presence of the primary user (PU on the channel to a fusion center (FC. We first design a new cooperative spectrum-sensing technique based on a convolutional neural network in which the FC uses historical sensing data to train the network for classification problem. The system is assumed to operate in a time-slotted manner. At the beginning of each time slot, the FC uses the current local decisions as input for the trained network to decide whether the PU is active or not in that time slot. In addition, legitimate transmissions can be vulnerable to a hidden eavesdropper, which always passively listens to the communication. Therefore, we further propose a transfer learning actor–critic algorithm for an SU to decide its operation mode to increase the security level under the constraint of limited energy. In this approach, the SU directly interacts with the environment to learn its dynamics (i.e., an arrival of harvested energy; then, the SU can either stay idle to save energy or transmit to the FC secured data that are encrypted using a suitable private-key encryption method to maximize the long-term effective security level of the network. We finally present numerical simulation results under various configurations to evaluate our proposed schemes.

The connection between cluster and collective quadrupole channels in 20 Ne and E 2-transition probabilities between the bound and continuous spectrum states

International Nuclear Information System (INIS)

Bystrenko, A.V.; Okhrimenko, I.P.

1993-01-01

The E 2-transition probabilities between the discrete and continuous spectrum states in 20 Ne are investigated using the two-channel version (making allowance for the connection between cluster and quadrupole channels) of the consistent microscopic approach,an algebraic version of the resonating-group method. The correctness of the approximation of the continuous spectrum by the discrete states, which is usual in collective models, the quadrupole sum rule and the giant quadrupole resonance phenomenon are considered. (author). 2 tab., 12 figs

Neutron energy spectrum from 120 GeV protons on a thick copper target

Energy Technology Data Exchange (ETDEWEB)

Shigyo, Nobuhiro; /Kyushu U.; Sanami, Toshiya; /KEK, Tsukuba; Kajimoto, Tsuyoshi; /Kyushu U.; Iwamoto, Yosuke; /JAEA, Ibaraki; Hagiwara, Masayuki; Saito, Kiwamu; /KEK, Tsukuba; Ishibashi, Kenji; /Kyushu U.; Nakashima, Hiroshi; Sakamoto, Yukio; /JAEA, Ibaraki; Lee, Hee-Seock; /Pohang Accelerator Lab.; Ramberg, Erik; /Fermilab

2010-08-01

Neutron energy spectrum from 120 GeV protons on a thick copper target was measured at the Meson Test Beam Facility (MTBF) at Fermi National Accelerator Laboratory. The data allows for evaluation of neutron production process implemented in theoretical simulation codes. It also helps exploring the reasons for some disagreement between calculation results and shielding benchmark data taken at high energy accelerator facilities, since it is evaluated separately from neutron transport. The experiment was carried out using a 120 GeV proton beam of 3E5 protons/spill. Since the spill duration was 4 seconds, protoninduced events were counted pulse by pulse. The intensity was maintained using diffusers and collimators installed in the beam line to MTBF. The protons hit a copper block target the size of which is 5cm x 5cm x 60 cm long. The neutrons produced in the target were measured using NE213 liquid scintillator detectors, placed about 5.5 m away from the target at 30{sup o} and 5 m 90{sup o} with respect to the proton beam axis. The neutron energy was determined by time-of-flight technique using timing difference between the NE213 and a plastic scintillator located just before the target. Neutron detection efficiency of NE213 was determined on basis of experimental data from the high energy neutron beam line at Los Alamos National Laboratory. The neutron spectrum was compared with the results of multiparticle transport codes to validate the implemented theoretical models. The apparatus would be applied to future measurements to obtain a systematic data set for secondary particle production on various target materials.

Long-time behaviour of discretizations of the simple pendulum equation

Energy Technology Data Exchange (ETDEWEB)

Cieslinski, Jan L [Uniwersytet w Bialymstoku, Wydzial Fizyki, ul. Lipowa 41, 15-424 Bialystok (Poland); Ratkiewicz, Boguslaw [Doctoral Studies, Wydzial Fizyki, Uniwersytet Adama Mickiewicza, Poznan (Poland)], E-mail: janek@alpha.uwb.edu.pl, E-mail: bograt@poczta.onet.pl

2009-03-13

We compare several discretizations of the simple pendulum equation in a series of numerical experiments. The stress is put on the long-time behaviour. The chosen numerical schemes are either symplectic maps or integrable (energy-preserving) maps, or both. Therefore, they preserve qualitative features of solutions (such as periodicity). We describe characteristic periodic time dependences of numerical estimates of the period and the amplitude, and explain them as systematic numerical by-effects produced by any method. Finally, we propose a new numerical scheme which is a modification of the discrete gradient method. This modified discrete gradient method preserves (almost exactly) the period of small oscillations for any time step.

Long-time behaviour of discretizations of the simple pendulum equation

International Nuclear Information System (INIS)

Cieslinski, Jan L; Ratkiewicz, Boguslaw

2009-01-01

We compare several discretizations of the simple pendulum equation in a series of numerical experiments. The stress is put on the long-time behaviour. The chosen numerical schemes are either symplectic maps or integrable (energy-preserving) maps, or both. Therefore, they preserve qualitative features of solutions (such as periodicity). We describe characteristic periodic time dependences of numerical estimates of the period and the amplitude, and explain them as systematic numerical by-effects produced by any method. Finally, we propose a new numerical scheme which is a modification of the discrete gradient method. This modified discrete gradient method preserves (almost exactly) the period of small oscillations for any time step

On the convergence of multigroup discrete-ordinates approximations

International Nuclear Information System (INIS)

Victory, H.D. Jr.; Allen, E.J.; Ganguly, K.

1987-01-01

Our analysis is divided into two distinct parts which we label for convenience as Part A and Part B. In Part A, we demonstrate that the multigroup discrete-ordinates approximations are well-defined and converge to the exact transport solution in any subcritical setting. For the most part, we focus on transport in two-dimensional Cartesian geometry. A Nystroem technique is used to extend the discrete ordinates multigroup approximates to all values of the angular and energy variables. Such an extension enables us to employ collectively compact operator theory to deduce stability and convergence of the approximates. In Part B, we perform a thorough convergence analysis for the multigroup discrete-ordinates method for an anisotropically-scattering subcritical medium in slab geometry. The diamond-difference and step-characteristic spatial approximation methods are each studied. The multigroup neutron fluxes are shown to converge in a Banach space setting under realistic smoothness conditions on the solution. This is the first thorough convergence analysis for the fully-discretized multigroup neutron transport equations

THE DETECTABILITY OF DARK MATTER ANNIHILATION WITH FERMI USING THE ANISOTROPY ENERGY SPECTRUM OF THE GAMMA-RAY BACKGROUND

International Nuclear Information System (INIS)

Hensley, Brandon S.; Pavlidou, Vasiliki; Siegal-Gaskins, Jennifer M.

2010-01-01

The energy dependence of the anisotropy (the anisotropy energy spectrum) of the large-scale diffuse gamma-ray background can reveal the presence of multiple source populations. Annihilating dark matter in the substructure of the Milky Way halo could give rise to a modulation in the anisotropy energy spectrum of the diffuse gamma-ray emission measured by Fermi, enabling the detection of a dark matter signal. We determine the detectability of a dark-matter-induced modulation for scenarios in which unresolved blazars are the primary contributor to the measured emission above ∼1 GeV and find that in some scenarios pair-annihilation cross sections on the order of the value expected for thermal relic dark matter can produce a detectable feature. We anticipate that the sensitivity of this technique to specific dark matter models could be improved by tailored likelihood analysis methods.

Discrete symmetries in periodic-orbit theory

International Nuclear Information System (INIS)

Robbins, J.M.

1989-01-01

The application of periodic-orbit theory to systems which possess a discrete symmetry is considered. A semiclassical expression for the symmetry-projected Green's function is obtained; it involves a sum over classical periodic orbits on a symmetry-reduced phase space, weighted by characters of the symmetry group. These periodic orbits correspond to trajectories on the full phase space which are not necessarily periodic, but whose end points are related by symmetry. If the symmetry-projected Green's functions are summed, the contributions of the unperiodic orbits cancel, and one recovers the usual periodic-orbit sum for the full Green's function. Several examples are considered, including the stadium billiard, a particle in a periodic potential, the Sinai billiard, the quartic oscillator, and the rotational spectrum of SF 6

Peak creation in the energy spectrum of laser-produced protons by phase rotation

International Nuclear Information System (INIS)

Noda, Akira; Nakamura, Shu; Iwashita, Yoshihisa; Shirai, Toshiyuki; Tongu, Hiromu; Ito, Hiroyuki; Souda, Hikaru; Yamazaki, Atsushi; Tanabe, Mikio; Daido, Hiroyuki; Mori, Michiaki; Kado, Masataka; Sagisaka, Akito; Ogura, Koichi; Nishiuchi, Mamiko; Orimo, Satoshi; Hayashi, Yukio; Yogo, Akifumi; Bulanov, Sergei; Esirkepov, Timur; Nagashima, Akira; Kimura, Toyoaki; Tajima, Toshiki; Fukumi, Atsushi; Li, Zhong

2007-01-01

In collaboration between JAEA, Kansai Photon Science Institute and Institute for Chemical Research, Kyoto University, proton generation from a thin foil target (Ti 3 or 5 μm in thickness) with use of 10 TW laser (JLITEX) has been performed. Proton production is optimized by real time proton energy measurement with use of TOF method. Phase rotation with use of an RF electric field phase-synchronized to the pulse laser enabled the creation of peaks with the spread of ∼7% in the energy spectrum of the produced protons, which resulted in the increase of the intensity ∼4 times at peak position. (author)

Experimental determination of spectral ratios and of neutrons energy spectrum in the fuel of the IPEN/MB-01 nuclear reactor

International Nuclear Information System (INIS)

Nunes, Beatriz Guimaraes

2012-01-01

This study aims to determine the spectral ratios and the neutron energy spectrum inside the fuel of IPEN/MB-01 Nuclear Reactor. These parameters are of great importance to accurately determine spectral physical parameters of nuclear reactors like reaction rates, fuel lifetime and also security parameters such as reactivity. For the experiment, activation detectors in the form of thin metal foils were introduced in a collapsible fuel rod. Then the rod was placed in the central position of the core which has a standard rectangular configuration of 26 x 28 fuel rods. There were used activation detectors from different elements such Au-197, U-238, Sc-45, Ni-58, Mg-24, Ti-47 and In-115 to cover a large range of the neutron energy spectrum. After the irradiation, the activation detectors were submitted to gamma spectrometry using a counting system with high purity Germanium, to obtain the reaction rates (saturation activity) per target nucleus. The spectral ratios were compared with calculated values obtained by the Monte Carlo method using the MCNP-4C code. The neutron energy spectrum was obtained inside the fuel rod using the SANDBP code with an input spectrum obtained by the MCNP-4C code, based on the saturation activity per target nucleus values of the activation detectors irradiated. (author)

Energy spectrum of 208Pb(n,x) reactions

Science.gov (United States)

Tel, E.; Kavun, Y.; Özdoǧan, H.; Kaplan, A.

2018-02-01

Fission and fusion reactor technologies have been investigated since 1950's on the world. For reactor technology, fission and fusion reaction investigations are play important role for improve new generation technologies. Especially, neutron reaction studies have an important place in the development of nuclear materials. So neutron effects on materials should study as theoretically and experimentally for improve reactor design. For this reason, Nuclear reaction codes are very useful tools when experimental data are unavailable. For such circumstances scientists created many nuclear reaction codes such as ALICE/ASH, CEM95, PCROSS, TALYS, GEANT, FLUKA. In this study we used ALICE/ASH, PCROSS and CEM95 codes for energy spectrum calculation of outgoing particles from Pb bombardment by neutron. While Weisskopf-Ewing model has been used for the equilibrium process in the calculations, full exciton, hybrid and geometry dependent hybrid nuclear reaction models have been used for the pre-equilibrium process. The calculated results have been discussed and compared with the experimental data taken from EXFOR.

Discrete Exterior Calculus Discretization of Incompressible Navier-Stokes Equations

KAUST Repository

Mohamed, Mamdouh S.; Hirani, Anil N.; Samtaney, Ravi

2017-01-01

A conservative discretization of incompressible Navier-Stokes equations over surface simplicial meshes is developed using discrete exterior calculus (DEC). Numerical experiments for flows over surfaces reveal a second order accuracy

MULTIMODE quantum calculations of vibrational energies and IR spectrum of the NO⁺(H₂O) cluster using accurate potential energy and dipole moment surfaces.

Science.gov (United States)

Homayoon, Zahra

2014-09-28

A new, full (nine)-dimensional potential energy surface and dipole moment surface to describe the NO(+)(H2O) cluster is reported. The PES is based on fitting of roughly 32,000 CCSD(T)-F12/aug-cc-pVTZ electronic energies. The surface is a linear least-squares fit using a permutationally invariant basis with Morse-type variables. The PES is used in a Diffusion Monte Carlo study of the zero-point energy and wavefunction of the NO(+)(H2O) and NO(+)(D2O) complexes. Using the calculated ZPE the dissociation energies of the clusters are reported. Vibrational configuration interaction calculations of NO(+)(H2O) and NO(+)(D2O) using the MULTIMODE program are performed. The fundamental, a number of overtone, and combination states of the clusters are reported. The IR spectrum of the NO(+)(H2O) cluster is calculated using 4, 5, 7, and 8 modes VSCF/CI calculations. The anharmonic, coupled vibrational calculations, and IR spectrum show very good agreement with experiment. Mode coupling of the water "antisymmetric" stretching mode with the low-frequency intermolecular modes results in intensity borrowing.

MULTIMODE quantum calculations of vibrational energies and IR spectrum of the NO+(H2O) cluster using accurate potential energy and dipole moment surfaces

Science.gov (United States)

Homayoon, Zahra

2014-09-01

A new, full (nine)-dimensional potential energy surface and dipole moment surface to describe the NO+(H2O) cluster is reported. The PES is based on fitting of roughly 32 000 CCSD(T)-F12/aug-cc-pVTZ electronic energies. The surface is a linear least-squares fit using a permutationally invariant basis with Morse-type variables. The PES is used in a Diffusion Monte Carlo study of the zero-point energy and wavefunction of the NO+(H2O) and NO+(D2O) complexes. Using the calculated ZPE the dissociation energies of the clusters are reported. Vibrational configuration interaction calculations of NO+(H2O) and NO+(D2O) using the MULTIMODE program are performed. The fundamental, a number of overtone, and combination states of the clusters are reported. The IR spectrum of the NO+(H2O) cluster is calculated using 4, 5, 7, and 8 modes VSCF/CI calculations. The anharmonic, coupled vibrational calculations, and IR spectrum show very good agreement with experiment. Mode coupling of the water "antisymmetric" stretching mode with the low-frequency intermolecular modes results in intensity borrowing.

MULTIMODE quantum calculations of vibrational energies and IR spectrum of the NO+(H2O) cluster using accurate potential energy and dipole moment surfaces

International Nuclear Information System (INIS)

Homayoon, Zahra

2014-01-01

A new, full (nine)-dimensional potential energy surface and dipole moment surface to describe the NO + (H 2 O) cluster is reported. The PES is based on fitting of roughly 32 000 CCSD(T)-F12/aug-cc-pVTZ electronic energies. The surface is a linear least-squares fit using a permutationally invariant basis with Morse-type variables. The PES is used in a Diffusion Monte Carlo study of the zero-point energy and wavefunction of the NO + (H 2 O) and NO + (D 2 O) complexes. Using the calculated ZPE the dissociation energies of the clusters are reported. Vibrational configuration interaction calculations of NO + (H 2 O) and NO + (D 2 O) using the MULTIMODE program are performed. The fundamental, a number of overtone, and combination states of the clusters are reported. The IR spectrum of the NO + (H 2 O) cluster is calculated using 4, 5, 7, and 8 modes VSCF/CI calculations. The anharmonic, coupled vibrational calculations, and IR spectrum show very good agreement with experiment. Mode coupling of the water “antisymmetric” stretching mode with the low-frequency intermolecular modes results in intensity borrowing

Broad Energy Range Neutron Spectroscopy using a Liquid Scintillator and a Proportional Counter: Application to a Neutron Spectrum Similar to that from an Improvised Nuclear Device.

Science.gov (United States)

Xu, Yanping; Randers-Pehrson, Gerhard; Marino, Stephen A; Garty, Guy; Harken, Andrew; Brenner, David J

2015-09-11

A novel neutron irradiation facility at the Radiological Research Accelerator Facility (RARAF) has been developed to mimic the neutron radiation from an Improvised Nuclear Device (IND) at relevant distances (e.g. 1.5 km) from the epicenter. The neutron spectrum of this IND-like neutron irradiator was designed according to estimations of the Hiroshima neutron spectrum at 1.5 km. It is significantly different from a standard reactor fission spectrum, because the spectrum changes as the neutrons are transported through air, and it is dominated by neutron energies from 100 keV up to 9 MeV. To verify such wide energy range neutron spectrum, detailed here is the development of a combined spectroscopy system. Both a liquid scintillator detector and a gas proportional counter were used for the recoil spectra measurements, with the individual response functions estimated from a series of Monte Carlo simulations. These normalized individual response functions were formed into a single response matrix for the unfolding process. Several accelerator-based quasi-monoenergetic neutron source spectra were measured and unfolded to test this spectroscopy system. These reference neutrons were produced from two reactions: T(p,n) 3 He and D(d,n) 3 He, generating neutron energies in the range between 0.2 and 8 MeV. The unfolded quasi-monoenergetic neutron spectra indicated that the detection system can provide good neutron spectroscopy results in this energy range. A broad-energy neutron spectrum from the 9 Be(d,n) reaction using a 5 MeV deuteron beam, measured at 60 degrees to the incident beam was measured and unfolded with the evaluated response matrix. The unfolded broad neutron spectrum is comparable with published time-of-flight results. Finally, the pair of detectors were used to measure the neutron spectrum generated at the RARAF IND-like neutron facility and a comparison is made to the neutron spectrum of Hiroshima.

COMPARISONS OF THE FINITE-ELEMENT-WITH-DISCONTIGUOUS-SUPPORT METHOD TO CONTINUOUS-ENERGY MONTE CARLO FOR PIN-CELL PROBLEMS

Energy Technology Data Exchange (ETDEWEB)

A. T. Till; M. Hanuš; J. Lou; J. E. Morel; M. L. Adams

2016-05-01

The standard multigroup (MG) method for energy discretization of the transport equation can be sensitive to approximations in the weighting spectrum chosen for cross-section averaging. As a result, MG often inaccurately treats important phenomena such as self-shielding variations across a material. From a finite-element viewpoint, MG uses a single fixed basis function (the pre-selected spectrum) within each group, with no mechanism to adapt to local solution behavior. In this work, we introduce the Finite-Element-with-Discontiguous-Support (FEDS) method, whose only approximation with respect to energy is that the angular flux is a linear combination of unknowns multiplied by basis functions. A basis function is non-zero only in the discontiguous set of energy intervals associated with its energy element. Discontiguous energy elements are generalizations of bands and are determined by minimizing a norm of the difference between snapshot spectra and their averages over the energy elements. We begin by presenting the theory of the FEDS method. We then compare to continuous-energy Monte Carlo for one-dimensional slab and two-dimensional pin-cell problem. We find FEDS to be accurate and efficient at producing quantities of interest such as reaction rates and eigenvalues. Results show that FEDS converges at a rate that is approximately first-order in the number of energy elements and that FEDS is less sensitive to weighting spectrum than standard MG.

DISCRETE MATHEMATICS/NUMBER THEORY

OpenAIRE

Mrs. Manju Devi*

2017-01-01

Discrete mathematics is the study of mathematical structures that are fundamentally discrete rather than continuous. In contrast to real numbers that have the property of varying "smoothly", the objects studied in discrete mathematics such as integers, graphs, and statements do not vary smoothly in this way, but have distinct, separated values. Discrete mathematics therefore excludes topics in "continuous mathematics" such as calculus and analysis. Discrete objects can often be enumerated by ...

On the spectral analysis of iterative solutions of the discretized one-group transport equation

International Nuclear Information System (INIS)

Sanchez, Richard

2004-01-01

We analyze the Fourier-mode technique used for the spectral analysis of iterative solutions of the one-group discretized transport equation. We introduce a direct spectral analysis for the iterative solution of finite difference approximations for finite slabs composed of identical layers, providing thus a complementary analysis that is more appropriate for reactor applications. Numerical calculations for the method of characteristics and with the diamond difference approximation show the appearance of antisymmetric modes generated by the iteration on boundary data. We have also utilized the discrete Fourier transform to compute the spectrum for a periodic slab containing N identical layers and shown that at the limit N → ∞ one obtains the familiar Fourier-mode solution

Beam collimation and energy spectrum compression of laser-accelerated proton beams using solenoid field and RF cavity

Energy Technology Data Exchange (ETDEWEB)

Teng, J.; Gu, Y.Q., E-mail: tengjian@mail.ustc.edu.cn; Zhu, B.; Hong, W.; Zhao, Z.Q.; Zhou, W.M.; Cao, L.F.

2013-11-21

This paper presents a new method of laser produced proton beam collimation and spectrum compression using a combination of a solenoid field and a RF cavity. The solenoid collects laser-driven protons efficiently within an angle that is smaller than 12 degrees because it is mounted few millimeters from the target, and collimates protons with energies around 2.3 MeV. The collimated proton beam then passes through a RF cavity to allow compression of the spectrum. Particle-in-cell (PIC) simulations demonstrate the proton beam transport in the solenoid and RF electric fields. Excellent energy compression and collection efficiency of protons are presented. This method for proton beam optimization is suitable for high repetition-rate laser acceleration proton beams, which could be used as an injector for a conventional proton accelerator.

Beam collimation and energy spectrum compression of laser-accelerated proton beams using solenoid field and RF cavity

Science.gov (United States)

Teng, J.; Gu, Y. Q.; Zhu, B.; Hong, W.; Zhao, Z. Q.; Zhou, W. M.; Cao, L. F.

2013-11-01

This paper presents a new method of laser produced proton beam collimation and spectrum compression using a combination of a solenoid field and a RF cavity. The solenoid collects laser-driven protons efficiently within an angle that is smaller than 12 degrees because it is mounted few millimeters from the target, and collimates protons with energies around 2.3 MeV. The collimated proton beam then passes through a RF cavity to allow compression of the spectrum. Particle-in-cell (PIC) simulations demonstrate the proton beam transport in the solenoid and RF electric fields. Excellent energy compression and collection efficiency of protons are presented. This method for proton beam optimization is suitable for high repetition-rate laser acceleration proton beams, which could be used as an injector for a conventional proton accelerator.

Beam collimation and energy spectrum compression of laser-accelerated proton beams using solenoid field and RF cavity

International Nuclear Information System (INIS)

Teng, J.; Gu, Y.Q.; Zhu, B.; Hong, W.; Zhao, Z.Q.; Zhou, W.M.; Cao, L.F.

2013-01-01

This paper presents a new method of laser produced proton beam collimation and spectrum compression using a combination of a solenoid field and a RF cavity. The solenoid collects laser-driven protons efficiently within an angle that is smaller than 12 degrees because it is mounted few millimeters from the target, and collimates protons with energies around 2.3 MeV. The collimated proton beam then passes through a RF cavity to allow compression of the spectrum. Particle-in-cell (PIC) simulations demonstrate the proton beam transport in the solenoid and RF electric fields. Excellent energy compression and collection efficiency of protons are presented. This method for proton beam optimization is suitable for high repetition-rate laser acceleration proton beams, which could be used as an injector for a conventional proton accelerator

Resonance and web structure in discrete soliton systems: the two-dimensional Toda lattice and its fully discrete and ultra-discrete analogues

International Nuclear Information System (INIS)

Maruno, Ken-ichi; Biondini, Gino

2004-01-01

We present a class of solutions of the two-dimensional Toda lattice equation, its fully discrete analogue and its ultra-discrete limit. These solutions demonstrate the existence of soliton resonance and web-like structure in discrete integrable systems such as differential-difference equations, difference equations and cellular automata (ultra-discrete equations)

Spectrum of a noncommutative formulation of the D=11 supermembrane with winding

International Nuclear Information System (INIS)

Garcia del Moral, M.P.; Restuccia, A.

2002-01-01

A regularized model of a noncommutative formulation of the double compactified D=11 supermembrane with nontrivial winding in terms of SU(N) valued maps is obtained. The condition of nontrivial winding is described in terms of a nontrivial line bundle introduced in the formulation of the compactified supermembrane. The multivalued geometrical objects of the model related to the nontrivial wrapping are described in terms of a SU(N) geometrical object, which in the N→∞ limit converges to the symplectic connection related to the area-preserving diffeomorphisms of the recently obtained noncommutative description of the compactified D=11 supermembrane [I. Martin, J. Ovalle, and A. Restuccia, Phys. Rev. D 64, 096001 (2001)]. The SU(N) regularized canonical Lagrangian is explicitly obtained. The spectrum of the Hamiltonian of the double compactified D=11 supermembrane is discussed. Generically, it contains local string such as spikes with zero energy. However, the sector of the theory corresponding to a principle bundle characterized by the winding number n=e0, described by the SU(N) model we propose, is shown to have no local stringlike spikes and hence the spectrum of this sector should be discrete