Energy harvesting efficiency of piezoelectric flags in axial flows
Michelin, Sebastien
2012-01-01
Self-sustained oscillations resulting from fluid-solid instabilities, such as the flutter of a flexible flag in axial flow, can be used to harvest energy if one is able to convert the solid energy into electricity. Here, this is achieved using piezoelectric patches attached to the surface of the flag that convert the solid deformation into an electric current powering purely resistive output circuits. Nonlinear numerical simulations in the slender-body limit, based on an explicit description of the coupling between the fluid-solid and electric systems, are used to determine the harvesting efficiency of the system, namely the fraction of the flow kinetic energy flux effectively used to power the output circuit, and its evolution with the system's parameters. The role of the tuning between the characteristic frequencies of the fluid-solid and electric systems is emphasized, as well as the critical impact of the piezoelectric coupling intensity. High fluid loading, classically associated with destabilization by ...
Energy Dissipation in Sandwich Structures During Axial Compression
DEFF Research Database (Denmark)
Urban, Jesper
2002-01-01
The purpose of this paper is to investigate the energy dissipation in sandwich structures during axial crushing. Axial crushing tests on six sandwich elements are described. The sandwich elements consist of a polyurethane core and E-glass/Polyester skin. The elements compare to full......-scale structural elements in fast sandwich vessels. Two of the crushing tests are simulated with the explicit finite element software LS-DYNA3D. The key results are load-end shortening relationship and the energy dissipation. Good agreement between the numerical predictions and the experiments are obtained. A...... simple analytical model for the energy dissipation during axial crushing is proposed. Keywords: Sandwich, Energy Dissipation, Axial Crushing, LS-DYNA, Analytical crushing models, Crashworthiness....
Dimensional enhancement of kinetic energies
Schleich, W. P.; Dahl, Jens Peder
2002-01-01
Simple thermodynamics considers kinetic energy to be an extensive variable which is proportional to the number, N, of particles. We present a quantum state of N non-interacting particles for which the kinetic energy increases quadratically with N. This enhancement effect is tied to the quantum centrifugal potential whose strength is quadratic in the number of dimensions of configuration space.
Dimensional enhancement of kinetic energies
DEFF Research Database (Denmark)
Schleich, W.P.; Dahl, Jens Peder
2002-01-01
Simple thermodynamics considers kinetic energy to be an extensive variable which is proportional to the number N of particles. We present a quantum state of N noninteracting particles for which the kinetic energy increases quadratically with N. This enhancement effect is tied to the quantum centr...... centrifugal potential whose strength is quadratic in the number of dimensions of configuration space....
Classical kinetic energy, quantum fluctuation terms and kinetic-energy functionals
Hamilton, I. P.; Mosna, Ricardo A.; Site, L. Delle
2006-01-01
We employ a recently formulated dequantization procedure to obtain an exact expression for the kinetic energy which is applicable to all kinetic-energy functionals. We express the kinetic energy of an N-electron system as the sum of an N-electron classical kinetic energy and an N-electron purely quantum kinetic energy arising from the quantum fluctuations that turn the classical momentum into the quantum momentum. This leads to an interesting analogy with Nelson's stochastic approach to quant...
Axial focusing of energy from a hypervelocity impact on earth
International Nuclear Information System (INIS)
We have performed computational simulations to determine how energy from a large hypervelocity impact on the Earth's surface would couple to its interior. Because of the first-order axial symmetry of both the impact energy source and the stress-wave velocity structure of the Earth, a disproportionate amount of energy is dissipated along the axis defined by the impact point and its antipode (point opposite the impact). For a symmetric and homogeneous Earth model, all the impact energy that is radiated as seismic waves into the Earth at a given takeoff angle (ray parameter), independent of azimuthal direction, is refocused (minus attenuation) on the axis of symmetry, regardless of the number of reflections and refractions it has experienced. Material on or near the axis of symmetry experiences more strain cycles with much greater amplitude than elsewhere, and therefore experiences more irreversible heating. The focusing is most intense in the upper mantle, within the asthenosphere, where seismic energy is most effectively converted to heat. For a sufficiently energetic impact, this mechanism might generate enough local heating to create an isostatic instability leading to uplift, possibly resulting in rifting, volcanism, or other rearrangement of the interior dynamics of the planet. These simulations demonstrate how hypervelocity impact energy can be transported to the Earth's interior, supporting the possibility of a causal link between large impacts on Earth and major internally-driven geophysical processes
International Nuclear Information System (INIS)
Presented here is a new numerical nodal method for the simulation of the axial power distribution within nuclear reactors using the one-dimensional one speed kinetics diffusion model with one group of delayed neutron precursors. Our method is based on a spectral analysis of the nodal kinetics equations. These equations are obtained by integrating the original kinetics equations separately over a time step and over a spatial node, and then considering flat approximations for the forward difference terms. These flat approximations are the only approximations that are considered in the method. As a result, the spectral nodal method for space - time reactor kinetics generates numerical solutions for space independent problems or for time independent problems that are completely free from truncation errors. We show numerical results to illustrate the method's accuracy for coarse mesh calculations. (author)
Energy Technology Data Exchange (ETDEWEB)
Takehiro, Shin-ichi, E-mail: takepiro@gfd-dennou.or [Research Institute for Mathematical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8502 (Japan)
2010-10-15
The kinetic energy budget analysis of spiraling columnar critical convection emerging in a rapidly rotating spherical shell is performed. In the cylindrical-radially elongated spiraling convection mode appearing as a critical mode at small Prandtl numbers, the kinetic energy generated in the inner region of the spherical shell is transported in a cylindrically radial manner and is dissipated near the outer boundary around the equator. However, when the Prandtl number is increased, the dynamical energy flux turns in the axial direction rather than in the cylindrically radial direction. The kinetic energy generated inside the shell is transported in the direction of the rotating axis and is dissipated near the outer boundary at the same cylindrically radial location. The existence of the axial component of the dynamical energy flux is attributed to the ageostrophic flows in the columnar vortices induced by viscous damping and buoyancy force. In spite of the existence of the axial component of dynamical energy flux, the obtained geometry of the axially integrated kinetic energy budget is consistent with the results using a two-dimensional rotating annulus model. Therefore, the interpretation of spiraling structure with the radial propagation properties of topographic Rossby waves is applicable to the three-dimensional spiraling columnar convection emerging in a rotating spherical shell. Flow patterns calculated from the dispersion relation of two-dimensional topographic Rossby waves in a rotating spherical shell well explain the structure of the three-dimensional spiraling columnar convection.
Indian Academy of Sciences (India)
M Bhoopal; N Ravi Kumar Reddy; S Satyanarayana
2003-04-01
Kinetics and equilibria of axial ligation of bromomethyl(aquo) cobaloxime by a series of straight chain primary amines (methylamine, ethylamine, propylamine, butylamine, pentylamine, hexylamine), cycloamines (cyclopentylamine, cyclohexylamine, cycloheptylamine) and secondary amines (N,N-dimethylamine, N,N-diethylamine) have been measured as functions of pH by spectrophotometric technique in aqueous solution, ionic strength 1 M (KCl) at 25°C. The rate of substitution of H2O varies with the Ka of incoming ligand, thus establishing nucleophilic participation of the ligand in the transition state. Binding and kinetic data are interpreted based on the basicity and steric influence of the entering ligand. To compare the rate constants of the entering ligands, pH independent second-order rate constants (on) are calculated.
How ambiguous is the local kinetic energy?
Anderson, James S M; Ayers, Paul W; Hernandez, Juan I Rodriguez
2010-08-26
The local kinetic energy and the closely related local electronic stress tensor are commonly used to elucidate chemical bonding patterns, especially for covalent bonds. We use three different approaches-transformation properties of the stress tensor, quasiprobability distributions, and the virial theorem from density-functional theory-to clarify the inherent ambiguity in these quantities, discussing the implications for analyses based on the local kinetic energy and stress tensor. An expansive-but not universal-family of local kinetic energy forms that includes the most common choices and is suitable for both chemical-bonding and atoms-in-molecule analysis is derived. A family of local electronic stress tensors is also derived. Several local kinetic energy functions that are mathematically justified, but unlikely to be conceptually useful, are derived. The implications of these forms for atoms-in-molecule analysis are discussed. PMID:20586467
Nanostructured energy devices equilibrium concepts and kinetics
Bisquert, Juan
2014-01-01
Due to the pressing needs of society, low cost materials for energy devices have experienced an outstanding development in recent times. In this highly multidisciplinary area, chemistry, material science, physics, and electrochemistry meet to develop new materials and devices that perform required energy conversion and storage processes with high efficiency, adequate capabilities for required applications, and low production cost. Nanostructured Energy Devices: Equilibrium Concepts and Kinetics introduces the main physicochemical principles that govern the operation of energy devices. It inclu
Concepts of radial and angular kinetic energies
DEFF Research Database (Denmark)
Dahl, Jens Peder; Schleich, W.P.
2002-01-01
We consider a general central-field system in D dimensions and show that the division of the kinetic energy into radial and angular parts proceeds differently in the wave-function picture and the Weyl-Wigner phase-space picture, Thus, the radial and angular kinetic energies are different quantities...... in the two pictures, containing different physical information, but the relation between them is well defined. We discuss this relation and illustrate its nature by examples referring to a free particle and to a ground-state hydrogen atom....
Kinetic energy of vortex knots and unknots
International Nuclear Information System (INIS)
New results on the kinetic energy of ideal vortex filaments in the shape of torus knots and unknots are presented. These knots are given by small-amplitude torus knot solutions (Ricca, 1993) to the Localized Induction Approximation (LIA) law. The kinetic energy of different knot and unknot types is calculated and presented for comparison. These results provide new information on relationships between geometry, topology and dynamics of complex vortex systems and help to establish possible connections between aspects of structural complexity of dynamical systems and vortical flows.
Utilization of rotor kinetic energy storage for hybrid vehicles
Hsu, John S.
2011-05-03
A power system for a motor vehicle having an internal combustion engine, the power system comprises an electric machine (12) further comprising a first excitation source (47), a permanent magnet rotor (28) and a magnetic coupling rotor (26) spaced from the permanent magnet rotor and at least one second excitation source (43), the magnetic coupling rotor (26) also including a flywheel having an inertial mass to store kinetic energy during an initial acceleration to an operating speed; and wherein the first excitation source is electrically connected to the second excitation source for power cycling such that the flywheel rotor (26) exerts torque on the permanent magnet rotor (28) to assist braking and acceleration of the permanent magnet rotor (28) and consequently, the vehicle. An axial gap machine and a radial gap machine are disclosed and methods of the invention are also disclosed.
Nonlocal kinetic-energy-density functionals
International Nuclear Information System (INIS)
In this paper we present nonlocal kinetic-energy functionals T[n] within the average density approximation (ADA) framework, which do not require any extra input when applied to any electron system and recover the exact kinetic energy and the linear response function of a homogeneous system. In contrast with previous ADA functionals, these present good behavior of the long-range tail of the exact weight function. The averaging procedure for the kinetic functional (averaging the Fermi momentum of the electron gas, instead of averaging the electron density) leads to a functional without numerical difficulties in the calculation of extended systems, and it gives excellent results when applied to atoms and jellium surfaces. copyright 1996 The American Physical Society
Aircraft Measurements of Atmospheric Kinetic Energy Spectra
DEFF Research Database (Denmark)
Lundtang Petersen, Erik; Lilly, D. K.
1983-01-01
Wind velocity data obtained from a jet airliner are used to construct kinetic energy spectra over the range of wavelengths from 2.5 to 2500 km. The spectra exhibit an approximate -5/3 slope for wavelengths of less than about 150 km, steepening to about -2.2 at larger scales. These results support...
On kinetic energy stabilized superconductivity in cuprates
Singh, D. J.
2006-01-01
The possibility of kinetic energy driven superconductivity in cuprates as was recently found in the $tJ$ model is discussed. We argue that the violation of the virial theorem implied by this result is serious and means that the description of superconductivity within the $tJ$ model is pathological.
Electric Vehicles Mileage Extender Kinetic Energy Storage
Directory of Open Access Journals (Sweden)
Jivkov Venelin
2015-03-01
Full Text Available The proposed paper considers small urban vehicles with electric hybrid propulsion systems. Energy demands are examined on the basis of European drive cycle (NEUDC and on an energy recuperation coefficient and are formulated for description of cycle energy transfers. Numerical simulation results show real possibilities for increasing in achievable vehicle mileage at the same energy levels of a main energy source - the electric battery. Kinetic energy storage (KES, as proposed to be used as an energy buffer and different structural schemes of the hybrid propulsion system are commented. Minimum energy levels for primary (the electric battery and secondary (KES sources are evaluated. A strategy for reduced power flows control is examined, and its impact on achievable vehicle mileage is investigated. Results show an additional increase in simulated mileage at the same initial energy levels.
Directory of Open Access Journals (Sweden)
Ye-Wei Zhang
2013-01-01
Full Text Available Nonlinear targeted energy transfer (TET is applied to suppress the excessive vibration of an axially moving string with transverse wind loads. The coupling dynamic equations used are modeled by a nonlinear energy sink (NES attached to the string to absorb vibrational energy. By a two-term Galerkin procedure, the equations are discretized, and the effects of vibration suppression by numerical methods are demonstrated. Results show that the NES can effectively suppress the vibration of the axially moving string with transverse wind loadings, thereby protecting the string from excessive movement.
Production of low axial energy spread ion beams with multicusp sources
International Nuclear Information System (INIS)
Multicusp ion sources are capable of producing ions with low axial energy spread which are necessary in applications such as: ion projection lithography (IPL) and focused ion beams for the next generation lithographic tools and nuclear science experiments such as radioactive ion beam production. The axial ion energy spread for multicusp source is approximately 6 eV which is too large for IPL and radioactive ion beam applications. The addition of a magnetic filter which consists of a pair of permanent magnets to the multicusp source reduces the energy spread considerably. The reduction is due to the improvement in the uniformity of the axial plasma potential distribution in the discharge region. Axial ion energy spread of the filament driven ion source has been measured using three different techniques. In all cases, it was found to be less than 2 eV. Energy spread of the radio frequency (RF) driven source has also been explored, and it was found to be less than 3 eV with the proper RF-shielding. A new multicusp source configuration has been designed and constructed to further reduce the energy spread. To achieve a more uniform axial plasma potential distribution, a cylindrical magnetic filter has been designed and constructed for a 2-cm-diameter source. This new source configuration, the co-axial source, is new in its kind. The energy spread in this source has been measured to be a record low of 0.6 eV. Because of the novelty of this device, some plasma parameters inside the source have been studied. Langmuir probe has been used to measure the plasma potential, the electron temperature and the density distribution
International Nuclear Information System (INIS)
Here we present a novel method to improve the kinetic energy resolution of a velocity map imaging(VMI) spectrometer. The main modifications, compared to the original design of Eppink and Parker (1997 Rev. Sci. Instrum. 68 3477), are two additional grid electrodes. One of the electrodes is a grounded grid and the other is an arc-shaped grid with negative voltages (or positive voltages for an ions spectrometer). The arc-shaped electrode is axially symmetrical around the spectrometer axis. The field constructed by the two electrodes is to compensate the dispersion of the ‘v’-shaped energy resolution. Simulations by SIMION and reconstructions by the basis set expansion Abel transform method show that the kinetic energy resolution can be improved drastically by our new method. Furthermore, the accuracy in the determination of the kinetic energy of ion/electrons remains unchanged with respect to the original design. (paper)
Computation of liquid drop deformation energy for axial symmetric nuclei
International Nuclear Information System (INIS)
Computation methods for deformation dependent terms of the nuclear potential energy in the Myers-Swiatecki's and Krappe-Nix's variants of the liquid-drop model are presented. Also, an extension of the Krappe-Nix integral, surface and Coulomb energies formulas in case of reflection asymmetric deformations leading to fragments with different charge-to-mass ratio is introduced. (author)
Indian Academy of Sciences (India)
Kotha Laxma Reddy; K Ashwini Kumar; N Ravi Kumar Reddy; Penumaka Nagababu; A Panasa Reddy; S Satyanarayana
2009-11-01
The kinetics and equilibria for the axial ligation of pyridine and substituted pyridines to bromomethyl(aqua)cobaloxime have been measured spectrophotometrically in aqueous solutions of ionic strength 1.0 M (KC1) at 25°C as a function of H. The binding constants and rate of formation increase in the order 4-NH2Py 4-EtPy > 4-MePy > Py > 2-NH2Py > 2-EtPy. The data have been interpreted based on the basicity of the ligand, -back bonding from Co(III) → L and hard and soft interactions. The rate of substitution of H2O varies with the pKa of the incoming ligand, thus establishing the existence of nucleophilic participation of the ligand in the transition state. We have investigated the DNA binding of bromomethyl(aqua)cobaloxime with DNA. Bromomethyl(ligand)cobaloximes were isolated and characterized by elemental analysis, IR and NMR (1H, 13C) spectra.
Imperfect dark energy from kinetic gravity braiding
International Nuclear Information System (INIS)
We introduce a large class of scalar-tensor models with interactions containing the second derivatives of the scalar field but not leading to additional degrees of freedom. These models exhibit peculiar features, such as an essential mixing of scalar and tensor kinetic terms, which we have named kinetic braiding. This braiding causes the scalar stress tensor to deviate from the perfect-fluid form. Cosmology in these models possesses a rich phenomenology, even in the limit where the scalar is an exact Goldstone boson. Generically, there are attractor solutions where the scalar monitors the behaviour of external matter. Because of the kinetic braiding, the position of the attractor depends both on the form of the Lagrangian and on the external energy density. The late-time asymptotic of these cosmologies is a de Sitter state. The scalar can exhibit phantom behaviour and is able to cross the phantom divide with neither ghosts nor gradient instabilities. These features provide a new class of models for Dark Energy. As an example, we study in detail a simple one-parameter model. The possible observational signatures of this model include a sizeable Early Dark Energy and a specific equation of state evolving into the final de-Sitter state from a healthy phantom regime
The effect of non-uniform damping on flutter in axial flow and energy harvesting strategies
Singh, Kiran; Michelin, Sebastien; de Langre, Emmanuel
2012-01-01
The problem of energy harvesting from flutter instabilities in flexible slender structures in axial flows is considered. In a recent study, we used a reduced order theoretical model of such a system to demonstrate the feasibility for harvesting energy from these structures. Following this preliminary study, we now consider a continuous fluid-structure system. Energy harvesting is modelled as strain-based damping and the slender structure under investigation lies in a moderate fluid loading ra...
Optimization of an axial-flux permanent-magnet generator for a small wind energy application
Vansompel, Hendrik; Sergeant, Peter; Dupré, Luc
2011-01-01
Axial-flux permanent-magnet synchronous machines have a high torque output at low speeds and are therefore very suitable for direct drive wind energy applications. This research focuses on: measures to improve the efficiency of the energy conversion; simplification of the construction and easy maintenance by introduction of a modular stator construction; adaptations required to obtain an efficient power conversion in direct drive wind energy applications.
Kinetic Energy Transport in Rayleigh--B\\'enard Convection
Petschel, Klaus; Stellmach, Stephan; Wilczek, Michael; Lülff, Johannes; Hansen, Ulli
2014-01-01
The kinetic energy balance in Rayleigh--B\\'{e}nard convection is investigated for the Prandtl number range $0.01\\le Pr \\le 150$ and for fixed Rayleigh number $Ra=5\\cdot10^{6}$. The kinetic energy balance is divided into a dissipation, a production and a flux term. We discuss profiles of all terms and find that the different contributions to the energy balance can be spatially separated into regions where kinetic energy is produced and where kinetic energy is dissipated. Analysing the Prandtl ...
Effects of the symmetry energy slope on the axial oscillations of neutron stars
Institute of Scientific and Technical Information of China (English)
Wen De-Hua; Zhou Ying
2013-01-01
The impact of symmetry energy slope L on the axial w-mode oscillations is explored,where the range of the constrained slope L of symmetry energy at saturation density is adopted from 25 MeV to 115 MeV while keeping the equation of state (EOS) of symmetric nuclear matter fixed.Based on the range of the symmetry energy slope,a constraint on the frequency and damping time of the wI-mode of the neutron star is given.It is found that there is a perfect linear relation between the frequency and the stellar mass for a fixed slope L,and the softer symmetry energy corresponds to a higher frequency.Moreover,it is confirmed that both the frequencies and damping times have a perfect universal scaling behavior for the EOSs with different symmetry energy slopes at saturation density.
Kinetic energy functional for Fermi vapors in spherical harmonic confinement
Minguzzi, A.; March, N. H.; Tosi, M. P.
2001-01-01
Two equations are constructed which reflect, for fermions moving independently in a spherical harmonic potential, a differential virial theorem and a relation between the turning points of kinetic energy and particle densities. These equations are used to derive a differential equation for the particle density and a non-local kinetic energy functional.
Reassessing the Plastic Hinge Model for Energy Dissipation of Axially Loaded Columns
Directory of Open Access Journals (Sweden)
R. M. Korol
2014-01-01
Full Text Available This paper investigates the energy dissipation potential of axially loaded columns and evaluates the use of a plastic hinge model for analysis of hi-rise building column collapse under extreme loading conditions. The experimental program considered seven axially loaded H-shaped extruded aluminum structural section columns having slenderness ratios that would be typical of floor-to-ceiling heights in buildings. All seven test specimens initially experienced minor-axis overall buckling followed by formation of a plastic hinge at the mid-height region, leading to local buckling of the flanges on the compression side of the plastic hinge, and eventual folding of the compression flanges. The experimental energy absorption, based on load-displacement relations, was compared to the energy estimates based on section plastic moment resistance based on measured yield stress and based on measured hinge rotations. It was found that the theoretical plastic hinge model underestimates a column’s actual ability to absorb energy by a factor in the range of 3 to 4 below that obtained from tests. It was also noted that the realizable hinge rotation is less than 180°. The above observations are based, of course, on actual columns being able to sustain high tensile strains at hinge locations without fracturing.
Hydro-Kinetic Energy Conversion : Resource and Technology
Grabbe, Mårten
2013-01-01
The kinetic energy present in tidal currents and other water courses has long been appreciated as a vast resource of renewable energy. The work presented in this doctoral thesis is devoted to both the characteristics of the hydro-kinetic resource and the technology for energy conversion. An assessment of the tidal energy resource in Norwegian waters has been carried out based on available data in pilot books. More than 100 sites have been identified as interesting with a total estimated theor...
The effect of non-uniform damping on flutter in axial flow and energy harvesting strategies
Singh, Kiran; de Langre, Emmanuel
2012-01-01
The problem of energy harvesting from flutter instabilities in flexible slender structures in axial flows is considered. In a recent study, we used a reduced order theoretical model of such a system to demonstrate the feasibility for harvesting energy from these structures. Following this preliminary study, we now consider a continuous fluid-structure system. Energy harvesting is modelled as strain-based damping and the slender structure under investigation lies in a moderate fluid loading range, for which {the flexible structure} may be destabilised by damping. The key goal of this work is to {analyse the effect of damping distribution and intensity on the amount of energy harvested by the system}. The numerical results {indeed} suggest that non-uniform damping distributions may significantly improve the power harvesting capacity of the system. For low damping levels, clustered dampers at the position of peak curvature are shown to be optimal. Conversely for higher damping, harvesters distributed over the wh...
Axial enrichment profile in advance nuclear energy power plant at supercritical-pressures
Energy Technology Data Exchange (ETDEWEB)
Tashakor, S. [Nuclear Science and Technology Research Institute (NSTRI), Tehran (Iran, Islamic Republic of). Reactor Research School; Islamic Azad Univ., Shiraz (Iran, Islamic Republic of). Dept. of Nuclear Engineering; Zarifi, E. [Nuclear Science and Technology Research Institute (NSTRI), Tehran (Iran, Islamic Republic of). Reactor Research School; Salehi, A.A. [Sharif University of Technology, Tehran (Iran, Islamic Republic of). Dept. of Nuclear Energy
2015-12-15
The High-Performance Light Water Reactor (HPLWR) is the European version of the advance nuclear energy power plant at Supercritical-pressure. A light water reactor at supercritical pressure, being currently under design, is the new generation of nuclear reactors. The aim of this study is to predict the HPLWR neutronic behavior of the axial enrichment profile with an average enrichment of 5 w/o U-235. Neutronic calculations are performed using WIMS and CITATION codes. Changes in neutronic parameter, such as Power Peaking Factor (PPF) are discussed in this paper.
Turbulence generation through intense kinetic energy sources
Maqui, Agustin F.; Donzis, Diego A.
2016-06-01
Direct numerical simulations (DNS) are used to systematically study the development and establishment of turbulence when the flow is initialized with concentrated regions of intense kinetic energy. This resembles both active and passive grids which have been extensively used to generate and study turbulence in laboratories at different Reynolds numbers and with different characteristics, such as the degree of isotropy and homogeneity. A large DNS database was generated covering a wide range of initial conditions with a focus on perturbations with some directional preference, a condition found in active jet grids and passive grids passed through a contraction as well as a new type of active grid inspired by the experimental use of lasers to photo-excite the molecules that comprise the fluid. The DNS database is used to assert under what conditions the flow becomes turbulent and if so, the time required for this to occur. We identify a natural time scale of the problem which indicates the onset of turbulence and a single Reynolds number based exclusively on initial conditions which controls the evolution of the flow. It is found that a minimum Reynolds number is needed for the flow to evolve towards fully developed turbulence. An extensive analysis of single and two point statistics, velocity as well as spectral dynamics and anisotropy measures is presented to characterize the evolution of the flow towards realistic turbulence.
A study of the kinetic energy density functional for atoms
International Nuclear Information System (INIS)
This paper studies the rigorous kinetic energy density functional at the level of the Hartree-Fock method for closed electron shell atoms. The behaviour of the kinetic energy and its components, is analysed as the atomic number N increases. It is shown that the increments of the specific energies for two consecutive closed electron shells atoms depend distinctly on the electron configuration of the last electron shell. 35 refs, 1 fig., 4 tabs
Zero kinetic energy photoelectron spectroscopy of triphenylene
Energy Technology Data Exchange (ETDEWEB)
Harthcock, Colin; Zhang, Jie; Kong, Wei, E-mail: wei.kong@oregonstate.edu [Department of Chemistry, Oregon State University, Corvallis, Oregon 97331 (United States)
2014-06-28
We report vibrational information of both the first electronically excited state and the ground cationic state of jet-cooled triphenylene via the techniques of resonantly enhanced multiphoton ionization (REMPI) and zero kinetic energy (ZEKE) photoelectron spectroscopy. The first excited electronic state S{sub 1} of the neutral molecule is of A{sub 1}′ symmetry and is therefore electric dipole forbidden in the D{sub 3h} group. Consequently, there are no observable Franck-Condon allowed totally symmetric a{sub 1}′ vibrational bands in the REMPI spectrum. All observed vibrational transitions are due to Herzberg-Teller vibronic coupling to the E′ third electronically excited state S{sub 3}. The assignment of all vibrational bands as e′ symmetry is based on comparisons with calculations using the time dependent density functional theory and spectroscopic simulations. When an electron is eliminated, the molecular frame undergoes Jahn-Teller distortion, lowering the point group to C{sub 2v} and resulting in two nearly degenerate electronic states of A{sub 2} and B{sub 1} symmetry. Here we follow a crude treatment by assuming that all e′ vibrational modes resolve into b{sub 2} and a{sub 1} modes in the C{sub 2v} molecular frame. Some observed ZEKE transitions are tentatively assigned, and the adiabatic ionization threshold is determined to be 63 365 ± 7 cm{sup −1}. The observed ZEKE spectra contain a consistent pattern, with a cluster of transitions centered near the same vibrational level of the cation as that of the intermediate state, roughly consistent with the propensity rule. However, complete assignment of the detailed vibrational structure due to Jahn-Teller coupling requires much more extensive calculations, which will be performed in the future.
Kinetic Energy-Based Temperature Computation in Non-Equilibrium Molecular Dynamics Simulation
Liu, Bin; Xu, Ran; He, Xiaoqiao
2009-01-01
The average kinetic energy is widely used to characterize temperature in molecular dynamics (MD) simulation. In this letter, the applicability of three types of average kinetic energy as measures of temperature is investigated, i.e., the total kinetic energy, kinetic energy without the centroid translation part, and thermal disturbance kinetic energy. Our MD simulations indicate that definitions of temperature based on the kinetic energy including rigid translational or rotational motion may ...
Fisher information, kinetic energy and uncertainty relation inequalities
International Nuclear Information System (INIS)
By interpolating between Fisher information and mechanical kinetic energy, we introduce a general notion of kinetic energy with respect to a parameter of Schroedinger wavefunctions from a statistical inference perspective. Kinetic energy is the sum of Fisher information and an integral of a parametrized analogue of quantum mechanical current density related to phase. A family of integral inequalities concerning kinetic energy and moments are established, among which the Cramer-Rao inequality and the Weyl-Heisenberg inequality, are special cases. In particular, the integral inequalities involving the negative order moments are relevant to the study of electron systems. Moreover, by specifying the parameter to a scale, we obtain a family of inequalities of uncertainty relation type which incorporate the position and momentum observables symmetrically in a single quantity. (author)
Indian Academy of Sciences (India)
Vaddeboina Sridhar; S Satyanarayana
2000-12-01
Kinetics and equilibria of the axial ligation of alkyl(aquo)cobaloximes by imidazole and cyanide have been measured spectrophotometrically in aqueous solutions of ionic strength 1.0 M at 25°C as a function of H. Comparison of IMD and CN- of CH3, C2H5 and BrCH2 cobaloximes indicates that their stability is in the order BrCH2 > CH3 > C2H5. As the electron-withdrawing capacity of the alkyl group trans to water increases, the electron density of the cobalt(III) decreases and thus it becomes a stronger Lewis acid and binds more strongly to imidazole and cyanide. The association and dissociation rate constants are better correlated to the relative softness of the ligand showing that cyanide binds 30 times faster than imidazole. These complexes are isolated and are characterized by IR and 1H NMR spectra.
International Nuclear Information System (INIS)
The influence of an axial energy spread on the negative-mass instability in a relativistic nonneutral E layer aligned parallel to a uniform axial magnetic field B0e/sub z/ is investigated. The stability analysis is carried out within the framework of the linearized Vlasov--Maxwell equations. It is assumed that the E layer is thin with radial thickness (2a) much smaller than the mean radius (R0), and that ν/γ0very-much-less-than1, where ν is Budker's parameter and γ0mc2 is the mean electron energy. Stability properties are investigated for the choice of electron distribution function in which all electrons have the same value of canonical angular momentum (P/sub theta P0/=const) and a step-function distribution in axial momentum p/sub z/. The negative-mass growth rate is calculated including the important stabilizing influence of axial energy spread (ΔE), and it is shown that a modest energy spread (ΔE/γ0mc2approx. = a few percent) is sufficient to stabilize perturbations with axial wavenumber satisfying k2R20> or approx. =1
Energy loss distributions of relativistic protons axially channeled in a bent silicon crystal
Energy Technology Data Exchange (ETDEWEB)
Stojanov, Nace, E-mail: nacestoj@pmf.ukim.mk [Institute of Physics, Faculty of Natural Sciences and Mathematics, Sts. Cyril and Methodius University, P.O. Box 162, 1000 Skopje (Macedonia, The Former Yugoslav Republic of); Petrović, Srdjan; Nešković, Nebojša [Laboratory of Physics (010), Vinča Institute of Nuclear Sciences, University of Belgrade, P.O. Box 522, 11001 Belgrade (Serbia)
2013-05-01
A detailed study of the energy loss distributions of the relativistic protons axially channeled in the bent < 100 > Si crystals is presented in this work. The bending angle was varied from 0 to 20 μrad, while the crystal thickness was equal to 1 mm. The proton energy was chosen to be 7 TeV in accordance with the Large Hadron Collider (LHC) project, at the European Organization for Nuclear Research (CERN), in Geneva, Switzerland. The energy loss distributions of the channeled protons were generated using the numerical solution of the proton equations of motion in the transverse plane and the computer simulation method. An accurate energy loss model was used, which takes into account the trajectory dependence of the energy loss of protons during their motion through the crystal channels. Further, the dispersion of the proton’s scattering angle caused by its collisions with the electrons of the crystal and the divergence of the proton beam were taken into account. The calculated dependence of the number of dechanneled protons on the bending angle was excellently fitted by the Gompertz type dechanneling function.
Indian Academy of Sciences (India)
Yuquan Zhang; Yuan Zheng; Chunxia Yang; Yantao Zhu; Xin Zhang
2015-12-01
The axial flow turbine applied in an overtopping wave energy convertor can continuously provide power with high efficiency and reliably. To study the rules between parameters of the turbine and flows, three different types of turbines with complete 3D flow-channel models were designed and optimized. It appears that diameter of the runner, flow rates, number of guide vanes and shape of outflow passage have a considerable impact on the performance of the whole convertor. The turbine with a diameter of 0.8 m, flow rate of 0.5 m3/s, double guide vanes and bent section in outflow passage shows the best comprehensive performance. Moreover, the results of the experiments indicate that the output power can be enhanced by increasing the wave overtopping rate.
Institute of Scientific and Technical Information of China (English)
Liu Yu-Min; Yu Zhong-Yuan
2009-01-01
Calculations of electronic structures about the semiconductor quantum dot and the semiconductor quantum ring are presented in this paper. To reduce the calculation costs, for the quantum dot and the quantum ring, their simplified axially symmetric shapes are utilized in our analysis. The energy dependent effective mass is taken into account in solving the Schrodinger equations in the single band effective mass approximation. The calculated results show that the energy dependent effective mass should be considered only for relatively small volume quantum dots or small quantum rings. For large size quantum materials, both the energy dependent effective mass and the parabolic effective mass can give the same results. The energy states and the effective masses of the quantum dot and the quantum ring as a function of geometric parameters are also discussed in detail.
International Nuclear Information System (INIS)
Using the assumption of a partially conserved axial-vector current and the conservation law for the electromagnetic current, we rederive a low-energy theorem for the pion electroproduction. In contrast to the traditional approach, we include all effects of off-shell nucleons and pions. We parametrize the axial-vector current in its most general form and apply the minimal substitution prescription to obtain the radiative axial-vector vertex that is required for gauge invariance. We split the full radiative axial-vector vertex into the isolated-pole contribution, the minimal-coupling interaction, and the remainder. The Ward-Takahashi identities are translated into the constraints on the pion electroproduction amplitude. The rigorous low-energy theorem is obtained for the zero four-momentum pion electroproduction. It is found that the off-shell matrix elements of the axial-vector current affect the isolated-pole term and the gauge term so that the low-energy theorem is at variance with the standard one given in the literature
Energy efficiency of an innovative vertical axial rotary kiln for pottery production
Directory of Open Access Journals (Sweden)
Carlos Andrés Forero Núñez
2015-01-01
Full Text Available Colombia is a remarkablecoal producer and exporter worldwide; several sectors use this resource for electricity and thermal energy production. Among them, the ceramic industry consumed 118,590 tons in 2011. Most of the pottery production companies in this country arelocated in rural areas and use old coal fired kilns with low energy efficiencies, generating environmental effects to the population nearby. Despite of the importance of these industries to the small rural economies, the government agencies have closed them due to the lack of development on cleaner devices. This work aims to analyze the thermal behavior of an innovative vertical axial rotary kiln for pottery production, and the energy efficiency varying operation mode. The kiln operated during seven hours needed three hours for stabilizing sintering temperature at 800°C. The mean temperatures of the loading, drying, sintering and cooling stage were 204°C, 223°C, 809°C and 321°C respectively. The convection and radiation heat losses were 15 % whereas the flue gas heat losses 18 %.During continuous operation, the kiln energy efficiency was about 60 %. This design proven to reach the temperatures required in the firing stage of the pottery production; moreover, a gas fuel was fuelled making the process cleaner and more efficient than coal-fired systems.
Strain Energy Approach for Axial and Torsional Fatigue Life Prediction in Aged NiCrMoV Steels
Song, Gee Wook; Hyun, Jung Seob; Ha, Jeong Soo
Axial and torsional low cycle fatigue tests were performed for NiCrMoV steels serviced low-pressure turbine rotor of nuclear power plant. The results were used to evaluate multiaxial fatigue life models including Tresca, von Mises and Brown and Miller's critical plane. The fatigue life predicted by the multiaxial fatigue models didn't correspond with the experimental results in small strain range. We proposed the total strain energy density model to predict torsional fatigue life from axial fatigue data. The total strain energy density model was found to best correlate the experimental data with predictions being within a factor of 2.
Study of electron-beam-pumped KrF laser kinetics and calculation of energy deposition
International Nuclear Information System (INIS)
The program of the electron-beam-pumped KrF laser kinetics has been developed. By using this program the relation of relaxation rate of upper laser level to the optimum output condition of the KrF laser is studied. It is expected that the laser output will be directly proportional to the relaxation rate under a given condition when the laser flux is near saturation. The numerical simulation showed that a rise (or drop) in pump rate is faster than that of the relaxation rate, the laser output rises (or drops) as well. The optimum condition of output is obtained. The pressure (5 ∼ 6 atm*), the pump power and the Ar, Kr, F2 mixture ratio are determined for the optimum condition. In order to study the energy deposition of the electron-beam-pumped KrF gas laser, the SANDYL and the ITS programs have been developed. The latter is the program with the axial magnetic field applied, while the former without any field. The energy depositions of two kinds of Ar/Kr/F2 mixtures at various pressures of the electron-beam-pumped cylindrical KrF laser are calculated with the SANDYL program. The results show that under the same conditions, the energy deposition with the axial magnetic field applied is 3 times larger than that without any magnetic field. The energy depositions of two kinds of Ar/Kr/F2
Energy loss distributions of 7 TeV protons axially channeled in the bent Si crystal
Stojanov, Nace; Petrović, Srdjan
2016-04-01
In this article, the energy loss distributions of relativistic protons axially channeled in the bent Si crystal are studied. The crystal thickness is equal to 1 mm, which corresponds to the reduced crystal thickness, Λ, equal to 1.22, whereas the bending angle, α, was varied from 0 to 30 μrad. The proton energy of 7 TeV was chosen in accordance with the concept of using the bent crystals as a tool for selective deflection of the beam halo particles from the LUA9 experiment at LHC. For the continuum interaction potential of the proton and the crystal the Molière's expression was used and the energy loss of a proton was calculated by applying the trajectory dependent stopping power model. Further, the uncertainness of the scattering angle of the proton caused by its collisions with the electrons of the crystal and the divergence of the proton beam were taken into account. The energy loss distribution of the channeled protons was obtained via the numerical solution of the proton equations of motion in the transverse plane and the computer simulation method. The analysis of the obtained theoretical data shows that the shape of the energy loss distribution strongly depends on the horizontal or vertical direction of the curvature of the crystal. The number of dechanneled protons as a function of the bending angle also strongly depends on the direction of the crystal's curvature. As a result, the dechanneling rates and ranges, obtained from the Gompertz type sigmoidal fitting functions, have different sets of values for different bending orientations. We have also studied the influence of the proton beam divergence on the energy loss distribution of channeled protons.
A Kinetic Model for the Energy Transfer in Phycobilisomes
Suter, Georg W.; Holzwarth, Alfred R.
1987-01-01
A kinetic model for the energy transfer in phycobilisome (PBS) rods of Synechococcus 6301 is presented, based on a set of experimental parameters from picosecond studies. It is shown that the enormous complexity of the kinetic system formed by 400-500 chromophores can be greatly simplified by using symmetry arguments. According to the model the transfer along the phycocyanin rods has to be taken into account in both directions, i.e., back and forth along the rods. The corresponding forward ra...
Renormalizing the kinetic energy operator in elementary quantum mechanics
Energy Technology Data Exchange (ETDEWEB)
Coutinho, F A B [Faculdade de Medicina, Universidade de Sao Paulo e LIM 01-HCFMUSP, 05405-000 Sao Paulo (Brazil); Amaku, M [Faculdade de Medicina Veterinaria e Zootecnia, Universidade de Sao Paulo, 05508-970 Sao Paulo (Brazil)], E-mail: coutinho@dim.fm.usp.br
2009-09-15
In this paper, we consider solutions to the three-dimensional Schroedinger equation of the form {psi}(r) = u(r)/r, where u(0) {ne} 0. The expectation value of the kinetic energy operator for such wavefunctions diverges. We show that it is possible to introduce a potential energy with an expectation value that also diverges, exactly cancelling the kinetic energy divergence. This renormalization procedure produces a self-adjoint Hamiltonian. We solve some problems with this new Hamiltonian to illustrate its usefulness.
Logarithmic entropy corrected holographic dark energy with nonminimal kinetic coupling
Amani, Ali R.; Sadeghi, J.; Farajollahi, H.; Pourali, M.
2012-01-01
In this paper, we have considered a cosmological model with the non--minimal kinetic coupling terms and investigated its cosmological implications with respect to the logarithmic entropy-- corrected holographic dark energy (LECHDE). The correspondence between LECHDE in flat FRW cosmology and the phantom dark energy model with the aim to interpret the current universe acceleration is also examined.
The quantum mechanics based on a general kinetic energy
Wei, Yuchuan
2016-01-01
In this paper, we introduce the Schrodinger equation with a general kinetic energy operator. The conservation law is proved and the probability continuity equation is deducted in a general sense. Examples with a Hermitian kinetic energy operator include the standard Schrodinger equation, the relativistic Schrodinger equation, the fractional Schrodinger equation, the Dirac equation, and the deformed Schrodinger equation. We reveal that the Klein-Gordon equation has a hidden non-Hermitian kinetic energy operator. The probability continuity equation with sources indicates that there exists a different way of probability transportation, which is probability teleportation. An average formula is deducted from the relativistic Schrodinger equation, the Dirac equation, and the K-G equation.
Energy Technology Data Exchange (ETDEWEB)
Welzel, B. [Stuttgart Univ. (Germany). Inst. fuer Stroemungsmechanik und Hydraulische Stroemungsmaschinen
1997-12-31
Within the framework of a project sponsored by the Stiftung Energieforschung Baden-Wuerttemberg, an axial turbine was developed as a flash evaporator, which permits energy recovery in all sectors where liquids in piping undergoes pressure relaxation. A specific feature of this turbine is that it forms part, complete with generator, of a single pipeline and that it does not cause any pressure variations worth mentioning in case of mains failure. The report describes the turbine, its advantages, and a pilot operation carried out with a prototype. The turbine`s performance is compared with a return pump. Further, the optimization of the hydraulic design by computer and the results of a market analysis are dealt with. (orig.) [Deutsch] Im Rahmen einer von der Stiftung Energieforschung Baden-Wuerttemberg gefoerderten Neuentwicklung wurde eine Axialturbine als Entspannungsturbine entwickelt, mit der eine Energierueckgewinnung in allen Bereichen erfolgen kann, in denen Fluessigkeiten in Rohrleitungssystemen entspannt werden. Die Turbine zeichnet sich unter anderem dadurch aus, dass sie komplett, inklusive Generator, innerhalb einer Rohrleitung angeordnet ist und bei Netzausfall keine nennenswerte Druckschwankung erzeugt. Es werden die Turbine, deren Vorteile sowie der mit einem Prototypen durchgefuehrte Betriebsversuch beschrieben. Weiterhin werden ein Vergleich des Betriebsverhaltens mit einer rueckwaertslaufenden Pumpe, die rechnerische Optimierung der hydraulischen Formgebung sowie die Ergebnisse einer Marktanalyse behandelt. (orig.)
Kinetic and Exchange Energy Densities near the Nucleus
Directory of Open Access Journals (Sweden)
Lucian A. Constantin
2016-04-01
Full Text Available We investigate the behavior of the kinetic and the exchange energy densities near the nuclear cusp of atomic systems. Considering hydrogenic orbitals, we derive analytical expressions near the nucleus, for single shells, as well as in the semiclassical limit of large non-relativistic neutral atoms. We show that a model based on the helium iso-electronic series is very accurate, as also confirmed by numerical calculations on real atoms up to two thousands electrons. Based on this model, we propose non-local density-dependent ingredients that are suitable for the description of the kinetic and exchange energy densities in the region close to the nucleus. These non-local ingredients are invariant under the uniform scaling of the density, and they can be used in the construction of non-local exchange-correlation and kinetic functionals.
Rizzo, Giuseppe; Bonanno, Antonino; Massarotti, Giorgio Paolo; Pastorello, Luca; Raimondo, Mariarosa; Veronesi, Federico; Blosi, Magda
2016-01-01
Axial piston pumps and motors are widely used in heavy-duty applications and play a fundamental role in hydrostatic and power split drives. The mechanical power losses in hydraulic piston pumps come from the friction between parts in relative motion. The improvement, albeit marginal, in overall efficiency of these components may significantly impact the global efficiency of the machine. The friction between slipper and swash plate is a functional key in an axial piston pump, especially when t...
Evaluating rainfall kinetic energy - intensity relationships with observed disdrometric data
Angulo-Martinez, Marta; Begueria, Santiago; Latorre, Borja
2016-04-01
Rainfall kinetic energy is required for determining erosivity, the ability of rainfall to detach soil particles and initiate erosion. Its determination relay on the use of disdrometers, i.e. devices capable of measuring the drop size distribution and velocity of falling raindrops. In the absence of such devices, rainfall kinetic energy is usually estimated with empirical expressions relating rainfall energy and intensity. We evaluated the performance of 14 rainfall energy equations in estimating one-minute rainfall energy and event total energy, in comparison with observed data from 821 rainfall episodes (more than 100 thousand one-minute observations) by means of an optical disdrometer. In addition, two sources of bias when using such relationships were evaluated: i) the influence of using theoretical terminal raindrop fall velocities instead of measured values; and ii) the influence of time aggregation (rainfall intensity data every 5-, 10-, 15-, 30-, and 60-minutes). Empirical relationships did a relatively good job when complete events were considered (R2 > 0.82), but offered poorer results for within-event (one-minute resolution) variation. Also, systematic biases where large for many equations. When raindrop size distribution was known, estimating the terminal fall velocities by empirical laws produced good results even at fine time resolution. The influence of time aggregation was very high in the estimated kinetic energy, although linear scaling may allow empirical correction. This results stress the importance of considering all these effects when rainfall energy needs to be estimated from more standard precipitation records. , and recommends the use of disdrometer data to locally determine rainfall kinetic energy.
Kinetic-energy functionals studied by surface calculations
DEFF Research Database (Denmark)
Vitos, Levente; Skriver, Hans Lomholt; Kollár, J.
1998-01-01
The self-consistent jellium model of metal surfaces is used to study the accuracy of a number of semilocal kinetic-energy functionals for independent particles. It is shown that the poor accuracy exhibited by the gradient expansion approximation and most of the semiempirical functionals in the lo...
The eddy kinetic energy budget in the Red Sea
Zhan, Peng
2016-06-09
The budget of eddy kinetic energy (EKE) in the Red Sea, including the sources, redistributions and sink, is examined using a high-resolution eddy-resolving ocean circulation model. A pronounced seasonally varying EKE is identified, with its maximum intensity occurring in winter, and the strongest EKE is captured mainly in the central and northern basins within the upper 200 m. Eddies acquire kinetic energy from conversion of eddy available potential energy (EPE), from transfer of mean kinetic energy (MKE), and from direct generation due to time-varying (turbulent) wind stress, the first of which contributes predominantly to the majority of the EKE. The EPE-to-EKE conversion occurs almost in the entire basin, while the MKE-to-EKE transfer appears mainly along the shelf boundary of the basin (200 miso-bath) where high horizontal shear interacts with topography. The EKE generated by the turbulent wind stress is relatively small and limited to the southern basin. All these processes are intensified during winter, when the rate of energy conversion is about four to five times larger than that in summer. The EKE is redistributed by the vertical and horizontal divergence of energy flux and the advection of the mean flow. As a main sink of EKE, dissipation processes is ubiquitously found in the basin. The seasonal variability of these energy conversion terms can explain the significant seasonality of eddy activities in the Red Sea. This article is protected by copyright. All rights reserved.
A proposed method to measure relativistic kinetic energy of electrons in Penning Trap
International Nuclear Information System (INIS)
Penning ion trap is a versatile tool which serves as a storage device for sub-atomic particles using a combination of quadrupolar electric potential for axial confinement and a strong magnetic field for radial confinement. Trapped particles have three oscillatory motions: 1) axial motion, along the direction of the magnetic field with frequency ωz, 2) the trap modified cyclotron motion at a higher frequency ω+, 3) slow magnetron motion with frequency ω+ , where ω- z + . The cryogenic Penning trap has so far been used for various precision measurements like the measurement of (g-2) parameter of electron and positron and several other similar studies. In this work, a new method of measuring the shape of a beta spectrum by high precision measurement of the relativistic kinetic energy of the electrons using a cryogenic Penning trap is proposed. Using this method, it might be possible to measure the shape of the end-point of a beta spectrum with a high precision enabling the mass measurement of electron-neutrino
Plasma neutrino energy loss due to the axial-vector current at the late stages of stellar evolution
Institute of Scientific and Technical Information of China (English)
LIU Jing-Jing
2009-01-01
Based on the Weinberg-Salam theory, the plasma neutrino energy loss rates of vector and axialvector contributions are studied.A ratable factor of the rates from the axial-vector current relative to those of the total neutrino energy loss rates is accurately calculated.The results show that the ratable factor will reach a maximum of 0.95 or even more at relatively higher temperature and lower density (such as P/μe＜ 10~7 g/cm~3).Thus the rates of the axial-vector contribution cannot be neglected.On the other hand, the rates of the axialvector contribution are on the order of～0.01% of the total vector contribution, which is in good agreement with Itoh's at relatively high density (such as p/μe＞10~7 g/cm~3) and a temperature of T≤10~(11) K.
International Nuclear Information System (INIS)
The frequencies and damping times of the axial w-mode oscillations of neutron stars are investigated using a nuclear equation of state (EOS) partially constrained by the available terrestrial laboratory data. It is found that the nuclear symmetry energy Esym(ρ), especially its high density behavior, plays an important role in determining both the eigen-frequencies and the damping times of these oscillations. (author)
Kinetic-energy density functional: Atoms and shell structure
International Nuclear Information System (INIS)
We present a nonlocal kinetic-energy functional which includes an anisotropic average of the density through a symmetrization procedure. This functional allows a better description of the nonlocal effects of the electron system. The main consequence of the symmetrization is the appearance of a clear shell structure in the atomic density profiles, obtained after the minimization of the total energy. Although previous results with some of the nonlocal kinetic functionals have given incipient structures for heavy atoms, only our functional shows a clear shell structure for most of the atoms. The atomic total energies have a good agreement with the exact calculations. Discussion of the chemical potential and the first ionization potential in atoms is included. The functional is also extended to spin-polarized systems. copyright 1996 The American Physical Society
Kinetics with deactivation of methylcyclohexane dehydrogenation for hydrogen energy storage
Energy Technology Data Exchange (ETDEWEB)
Maria, G.; Marin, A.; Wyss, C.; Mueller, S.; Newson, E. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)
1997-06-01
The methylcyclohexane dehydrogenation step to recycle toluene and release hydrogen is being studied as part of a hydrogen energy storage project. The reaction is performed catalytically in a fixed bed reactor, and the efficiency of this step significantly determines overall system economics. The fresh catalyst kinetics and the deactivation of the catalyst by coke play an important role in the process analysis. The main reaction kinetics were determined from isothermal experiments using a parameter sensitivity analysis for model discrimination. An activation energy for the main reaction of 220{+-}11 kJ/mol was obtained from a two-parameter model. From non-isothermal deactivation in PC-controlled integral reactors, an activation energy for deactivation of 160 kJ/mol was estimated. A model for catalyst coke content of 3-17 weight% was compared with experimental data. (author) 3 figs., 6 refs.
Systems engineering analysis of kinetic energy weapon concepts
Energy Technology Data Exchange (ETDEWEB)
Senglaub, M.
1996-06-01
This study examines, from a systems engineering design perspective, the potential of kinetic energy weapons being used in the role of a conventional strategic weapon. Within the Department of Energy (DOE) complex, strategic weapon experience falls predominantly in the nuclear weapons arena. The techniques developed over the years may not be the most suitable methodologies for use in a new design/development arena. For this reason a more fundamental approach was pursued with the objective of developing an information base from which design decisions might be made concerning the conventional strategic weapon system concepts. The study examined (1) a number of generic missions, (2) the effects of a number of damage mechanisms from a physics perspective, (3) measures of effectiveness (MOE`s), and (4) a design envelope for kinetic energy weapon concepts. With the base of information a cut at developing a set of high-level system requirements was made, and a number of concepts were assessed against these requirements.
Crystal dissolution kinetics and Gibbs free energy
Energy Technology Data Exchange (ETDEWEB)
Luettge, Andreas [Department of Earth Science and the Department of Chemistry, Center for Biological and Environmental Nanotechnology, Rice University, 6100 Main Street, Houston, TX 77005 (United States)]. E-mail: aluttge@rice.edu
2006-02-15
The dependence of dissolution rates on the difference of Gibbs free energy is of critical importance for our understanding of crystal dissolution, reactive flow models and their applications to a variety of environmentally related problems. Here, we review experimental data generated with mineral powders and single crystals to develop a better understanding of apparent inconsistencies between otherwise internally consistent data sets. Additional information from direct surface observations and measurements with vertical scanning interferometry (VSI) and atomic force microscopy (AFM) of albite dissolution at 25, 150 and 185 deg. C may shed new light on this old but unsolved question. Our discussion is based on the importance of etch pit development, its {delta}G dependence, and the pits' role as a source for steps and step movement in the dissolution process. Results indicate that reaction history may be of critical importance in determining the overall reaction mechanism and its rate. Different rates are observed for systems having otherwise identical {delta}G {sub r} acquired from increasing versus decreasing disequilibrium positions. In this context, we finally discuss the validity of the common application of transition state theory (TST) to elementary and overall reactions governing the dissolution process. In this discussion of crystal dissolution, we contrast TST applications with a stochastic, many-body treatment that has led to the development of a stepwave model. This discussion also focuses on the controversy caused by the rivalry between surface adsorption models and a probabilistic model that seeks to incorporate the full three-dimensional crystal structure.
Mesoscale and macroscale kinetic energy fluxes from granular fabric evolution
Walker, David M.; Tordesillas, Antoinette; Froyland, Gary
2014-03-01
Recent advances in high-resolution measurements means it is now possible to identify and track the local "fabric" or contact topology of individual grains in a deforming sand throughout loading history. These provide compelling impetus to the development of methods for inferring changes in the contact forces and energies at multiple spatiotemporal scales, using information on grain contacts alone. Here we develop a surrogate measure of the fluctuating kinetic energy based on changes in the local contact topology of individual grains. We demonstrate the method for dense granular materials under quasistatic biaxial shear. In these systems, the initially stable and solidlike response eventually gives way to liquidlike behavior and global failure. This crossover in mechanical behavior, akin to a phase transition, is marked by bursts of kinetic energy and frictional dissipation. Mechanisms underlying this release of energy include the buckling of major load-bearing structures known as force chains. These columns of grains represent major repositories for stored strain energy. Stored energy initially accumulates at all of the contacts along the force chain, but is released collectively when the chain overloads and buckles. The exact quantification of the buildup and release of energy in force chains, and the manner in which force chain buckling propagates in the sample (i.e., diffuse and systemwide versus localized into shear bands), requires detailed knowledge of contact forces. To date, however, the forces at grain contacts continue to elude measurement in natural granular materials like sand. Here, using data from computer simulations, we show that a proxy for the fluctuating kinetic energy in dense granular materials can be suitably constructed solely from the evolving properties of the grain's local contact topology. Our approach directly relates the evolution of fabric to energy flux and makes possible research into the propagation of failure from measurements of
Effects of directed and kinetic energy weapons on spacecraft
Energy Technology Data Exchange (ETDEWEB)
Fraas, A P
1986-12-01
The characteristics of the various directed energy beams are reviewed, and their damaging effects on typical materials are examined for a wide range of energy pulse intensities and durations. Representative cases are surveyed, and charts are presented to indicate regions in which damage to spacecraft structures, particularly radiators for power plants, would be likely. The effects of kinetic energy weapons, such as bird-shot, are similarly examined. The charts are then applied to evaluate the effectiveness of various measures designed to reduce the vulnerability of spacecraft components, particularly nuclear electric power plants.
Reaction Path Optimization with Holonomic Constraints and Kinetic Energy Potentials
International Nuclear Information System (INIS)
Two methods are developed to enhance the stability, efficiency, and robustness of reaction path optimization using a chain of replicas. First, distances between replicas are kept equal during path optimization via holonomic constraints. Finding a reaction path is, thus, transformed into a constrained optimization problem. This approach avoids force projections for finding minimum energy paths (MEPs), and fast-converging schemes such as quasi-Newton methods can be readily applied. Second, we define a new objective function - the total Hamiltonian - for reaction path optimization, by combining the kinetic energy potential of each replica with its potential energy function. Minimizing the total Hamiltonian of a chain determines a minimum Hamiltonian path (MHP). If the distances between replicas are kept equal and a consistent force constant is used, then the kinetic energy potentials of all replicas have the same value. The MHP in this case is the most probable isokinetic path. Our results indicate that low-temperature kinetic energy potentials (7eq-to-Cax isomerization of an alanine dipeptide, the 4C1-to-1C4 transition of an α-D-glucopyranose, and the helix-to-sheet transition of a GNNQQNY heptapeptide. By applying the methods developed in this work, convergence of reaction path optimization can be achieved for these complex transitions, involving full atomic details and a large number of replicas (>100). For the case of helix-to-sheet transition, we identify pathways whose energy barriers are consistent with experimental measurements. Further, we develop a method based on the work energy theorem to quantify the accuracy of reaction paths and to determine whether the atoms used to define a path are enough to provide quantitative estimation of energy barriers.
International Nuclear Information System (INIS)
The axial buckling behavior of magnetically affected current-carrying nanowires is studied accounting for the surface energy effect. Using Euler–Bernoulli beam theory, the Lorentz force on the nanowire is determined and the governing equations are established. By application of the Galerkin approach and assumed mode method, the critical axial compressive load of the nanostructure is evaluated in the cases of simply supported and fully clamped ends. The effects of surface energy, electric current, strength of the magnetic field, slenderness ratio, and nanowire’s radius on the axial buckling loads are comprehensively discussed. The obtained results reveal that both the electric current and exerted magnetic field endanger the axial stability of the nanowire. For high levels of electric current or magnetic field strength, the surface effect becomes significant in the axial buckling performance of the nanostructure. (paper)
Universal Power Law for Relationship between Rainfall Kinetic Energy and Rainfall Intensity
Seung Sook Shin; Sang Deog Park; Byoung Koo Choi
2016-01-01
Rainfall kinetic energy has been linked to linear, exponential, logarithmic, and power-law functions using rainfall intensity as an independent variable. The power law is the most suitable mathematical expression used to relate rainfall kinetic energy and rainfall intensity. In evaluating the rainfall kinetic energy, the empirical power laws have shown a larger deviation than other functions. In this study, universal power law between rainfall kinetic energy and rainfall intensity was propose...
International Nuclear Information System (INIS)
This paper presents a novel vibration-based piezoelectric energy harvester capable of passively tuning its resonant frequency to a wide range of frequencies. The device comprises a dual bimorph with a mass at its free end. A novel sliding mechanism, consisting of two oblique springs connected to the tip mass, is proposed to widen the resonance frequency of the device even to very low frequencies. The application of two oblique springs results in an additional stiffness and axial load that are introduced within the system, such that the resonance frequency of the device is now a function of both the stiffness and axial load associated with the spring forces. An operator can manually change the resonance frequency of the harvester just by small adjustments of the sliding mechanism. Further, the device allows one to tune the resonance frequency of the beam to match very low frequencies without the requirement of having a large proof mass. The analytical solution of an axially loaded cantilevered piezoelectric energy harvester with tip stiffness, using Euler–Bernoulli beam assumptions, is presented. A parametric case study is presented to demonstrate the performance of the device. (paper)
Rotational and divergent kinetic energy in the mesoscale model ALADIN
Directory of Open Access Journals (Sweden)
V. Blažica
2013-03-01
Full Text Available Kinetic energy spectra from the mesoscale numerical weather prediction (NWP model ALADIN with horizontal resolution 4.4 km are split into divergent and rotational components which are then compared at horizontal scales below 300 km and various vertical levels. It is shown that about 50% of kinetic energy in the free troposphere in ALADIN is divergent energy. The percentage increases towards 70% near the surface and in the upper troposphere towards 100 hPa. The maximal percentage of divergent energy is found at stratospheric levels around 100 hPa and at scales below 100 km which are not represented by the global models. At all levels, the divergent energy spectra are characterised by shallower slopes than the rotational energy spectra, and the difference increases as horizontal scales become larger. A very similar vertical distribution of divergent energy is obtained by using the standard ALADIN approach for the computation of spectra based on the extension zone and by applying detrending approach commonly used in mesoscale NWP community.
Fragment kinetic energy distributions in ion induced CO2 fragmentation
International Nuclear Information System (INIS)
The dissociation of CO3+2 formed in heavy ion induced ionization of CO2 has been studied using the technique of time of flight mass spectroscopy with position sensitive ion detector, with 5 MeV/u Si12+ ions as projectiles. The kinetic energy released in the CO3+2→ C+ + O+ + O+ is measured and compared to theoretical ab initio calculations as well as photoionization results.
Kinetic Energy of Tornadoes in the United States
Tyler Fricker; James B. Elsner
2015-01-01
Tornadoes can cause catastrophic destruction. Here total kinetic energy (TKE) as a metric of destruction is computed from the fraction of the tornado path experiencing various damage levels and a characteristic wind speed for each level. The fraction of the path is obtained from a model developed for the Nuclear Regulatory Commission that combines theory with empirical data. TKE is validated as a useful metric by comparing it to other indexes and loss indicators. Half of all tornadoes have TK...
Fragmentation and mean kinetic energy release of the nitrogen molecule
International Nuclear Information System (INIS)
Ionization and fragmentation of the N2 molecule in coincidence with the final projectile charge state have been measured for the impact of 0.188-0.875 MeV/amu He+ projectiles. The average kinetic energy release (KER) of the target ionic fragments is derived from the peak widths of their time-of-flight distributions. It is shown that the KER's for singly-charged products follow scaling laws irrespectively to the collision channel
International Nuclear Information System (INIS)
In this paper, the generation of high-quality and high-energy micro electron beam in vacuum by a chirped Gaussian laser pulse in the presence of an axial magnetic field is numerically investigated. The features of energy and angular spectra, emittances, and position distribution of electron beam are compared in two cases, i.e., in the presence and absence of an external magnetic field. The electron beam is accelerated with higher energy and qualified in spatial distribution in the presence of the magnetic field. The presence of an axial magnetic field improves electron beam spatial quality as well as its gained energy through keeping the electron motion parallel to the direction of propagation for longer distances. It has been found that a 64 μm electron bunch with about MeV initial energy becomes a 20 μm electron beam with high energy of the order of GeV, after interacting with a laser pulse in the presence of an external magnetic field
Energy Technology Data Exchange (ETDEWEB)
Akou, H., E-mail: h.akou@nit.ac.ir; Hamedi, M. [Department of Physics, Faculty of Basic Science, Babol University of Technology, Babol 47148-71167 (Iran, Islamic Republic of)
2015-10-15
In this paper, the generation of high-quality and high-energy micro electron beam in vacuum by a chirped Gaussian laser pulse in the presence of an axial magnetic field is numerically investigated. The features of energy and angular spectra, emittances, and position distribution of electron beam are compared in two cases, i.e., in the presence and absence of an external magnetic field. The electron beam is accelerated with higher energy and qualified in spatial distribution in the presence of the magnetic field. The presence of an axial magnetic field improves electron beam spatial quality as well as its gained energy through keeping the electron motion parallel to the direction of propagation for longer distances. It has been found that a 64 μm electron bunch with about MeV initial energy becomes a 20 μm electron beam with high energy of the order of GeV, after interacting with a laser pulse in the presence of an external magnetic field.
Triebwasser-Freese, D.; Tharayil, N.; Preston, C. M.; Gerard, P.
2013-12-01
Recently, it has been suggested that lignin exhibit a turnover rate of less than 6 years, suggesting that the enzymatic mechanisms mediating the decay of lignin are less understood. One factor that could be affecting the mean residence time of lignin in the soil is the catalytic efficiency of soil oxidoreductase enzymes. We characterized the spatial and seasonal transitions in the Michaelis-Menten kinetics and activation energy of the soil oxidoreductase enzyme, peroxidase, across three ecosystems of differing litter chemistries- pine, deciduous forest, and a cultivated field- and associate it to the soil lignin chemistries. To interpret the combined effect of Vmax and Km, the two parameters were integrated into one term which we defined as the catalytic efficiency. Generally, the peroxidases in pine soils exhibited the highest Vmax and Km, resulting in the lowest catalytic efficiency, followed by that in the deciduous soils. Meanwhile, the agricultural soils which exhibited the lowest Vmax and Km contained the highest catalytic efficiency of peroxidase. Through linear regression analysis of the kinetic parameters to the soil lignin chemistry, we discerned that the catalytic efficiency term best associated to the lignin monomer ratios (C/V, P/V, and SCV/V). The Activation Energy of peroxidase varied by depth, and seasons across the ecosystems. However, the Activation Energy of peroxidase did not relate to the lignin chemistry or quantity. Collectively, our results show that although the peroxidase Vmax and Km in the phenolic-poor soils are low, the degradation efficiency of peroxidases in this soils can be equivalent or exceed that of phenolic-rich soils. This study, through the characterization of Michaelis-Menten kinetics, provides a new insight into the mechanisms that could moderate the decomposition of lignin in soils.
When and How Does A Prominence-like Jet Gain Kinetic Energy?
Liu, J.; Wang, Y.; Zhang, Q.; Liu, K.; Shen, C.
2013-12-01
Usually a jet is triggered by a brightening or flare, which provides the first driving force. In this process, magnetic reconnection is thought to be the mechanism to convert magnetic energy into jet's kinetic energy. However, most jets could reach an unusual height and end far after the end of its associated flare. This fact implies another way continuously transferring magnetic energy into kinetic energy after the reconnection. This picture is well known, but how and how much magnetic energy is released through the way other than the reconnection is still unclear. Here, through studying a prominence-like jet observed by AIA and EUVI, we reveal the continuously relaxation of post-reconnection magnetic field structure is an important process to support a jet. The kinetic energy of the jet gained through this way is 1.6 times of that from the reconnection. The resultant energy flux is hundreds of the required for local coronal heating, suggesting such jets are a possible source to keep corona hot. Rotational motion appearing all the time during the jet implies the torsional Alfven wave induced during reconnection is not the only mechanism to release magnetic energy and drive jets. Left column: Difference images taken by SDO/AIA at 304A passband. The FOV of the images is 430"x430". Right column: Difference images from STEREO-A/EUVI at the same passband. The FOV is 450"x450". Since STEREO-A was 120 degree apart away from SDO on 2012 July 8, the SDO limb event right happened ondisk in the view of STEREO-A. Black and red solid curve: integrated intensity over the cross-section of the jet at different height at 19:11 UT and 19:47 UT, respectively. The two horizontal dashed lines are their average values. Black and red dashed curve with asterisks: axial speed with errors of the eight sub-jets shown in Figure 3 at 19:11 UT and 19:47 UT , respectively. Blue dashed curve with diamonds: angular speed with errors of the jet at different height.
Maximum kinetic energy considerations in proton stereotactic radiosurgery
Sengbusch, Evan R.; Mackie, Thomas R.
2016-01-01
The purpose of this study was to determine the maximum proton kinetic energy required to treat a given percentage of patients eligible for stereotactic radiosurgery (SRS) with coplanar arc-based proton therapy, contingent upon the number and location of gantry angles used. Treatment plans from 100 consecutive patients treated with SRS at the University of Wisconsin Carbone Cancer Center between June of 2007 and March of 2010 were analyzed. For each target volume within each patient, in-house software was used to place proton pencil beam spots over the distal surface of the target volume from 51 equally-spaced gantry angles of up to 360°. For each beam spot, the radiological path length from the surface of the patient to the distal boundary of the target was then calculated along a ray from the gantry location to the location of the beam spot. This data was used to generate a maximum proton energy requirement for each patient as a function of the arc length that would be spanned by the gantry angles used in a given treatment. If only a single treatment angle is required, 100% of the patients included in the study could be treated by a proton beam with a maximum kinetic energy of 118 MeV. As the length of the treatment arc is increased to 90°, 180°, 270°, and 360°, the maximum energy requirement increases to 127, 145, 156, and 179 MeV, respectively. A very high percentage of SRS patients could be treated at relatively low proton energies if the gantry angles used in the treatment plan do not span a large treatment arc. Maximum proton kinetic energy requirements increase linearly with size of the treatment arc. PMID:21844866
Nuclear form in scission point at different kinetic energies
International Nuclear Information System (INIS)
Full text: Form of a fission nucleus in the scission point is determined by the relation of the future fragments masses, deformation, shell structure and quantum-mechanical effects (nuclear temperature, nuclear friction, intranuclear interaction). It is important to establish the contribution of each of these factors in dynamics of nuclear fission, that will allow more precisely to describe formation of the fragments nuclei at descent from the saddle point to the scission point. In the final account, the form of a nucleus determines kinetic energy of scattering fragments and their energy of excitation, and energy of deformation. The kinetic energy, charge and masses of scattering fragments are experimentally determined. Using modeling performances of fission process, by these experimental results it is possible to find the form of a fission nucleus in the scission point. On procedure in detail described in [1] there was determined a distance between fragments in the scission point at the fixed values of kinetic energy Ek for an easy fragment in a range of mass numbers 68 235U by thermal neutrons. The values of a fragment charge ZL were used from work [2]. Further on a technique offered in work [3], there were determined sizes of fragments nuclei and their parameters of deformations βL and βh. The executed accounts show, what at values 88 MeV k L = 76 and Ah = 134 (βL, βh ∼ 0) is observed. These fragments are formed with small excitation; the issue of neutrons from them practically is absent. At additional to them of fragments (Ah = 160, AL = 102) are observed of the large energy of excitation and deformation. The fragments with AL h h k, TKE, ZL/Zh, AL/Ah) and to use independent yield of fragments, it is possible to determine a degree of influence of these parameters on the form of a fission nucleus in the scission point. The dependences between these parameters are established. (author)
Neutron Generation and Kinetic Energy of Expanding Laser Plasmas
Institute of Scientific and Technical Information of China (English)
HUANG Yong-Sheng; WANG Nai-Yan; DUAN Xiao-Jiao; LAN Xiao-Fei; TAN Zhi-Xin; TANG Xiu-Zhang; HE Ye-Xi
2007-01-01
We investigate the kinetic energy of expanding plasma of a solid target heated by a ultra-short and ultra-intense laser pulse and the efficiency of energy coupling between the ultra-intense laser pulse and the solid target, in order to increase the utilization ratio of laser energy and to raise the neutron generation farther. Some new ideas about improving the energy utilization by head-on collisions between the expanding plasmas are proposed. The significance is the raise of generation of shorter duration neutron, of the order of picoseconds, which allows for an increase of energy resolution in time-of-flight experiments and also for the investigation of the dynamics of nuclear processes with high temporal resolution.
Enhanced propagation of rainfall kinetic energy in the UK
Diodato, Nazzareno; Bellocchi, Gianni
2016-07-01
A gridded 0.25° reconstruction of rainfall kinetic energy (RKE) over the UK, on the basis of pluviometric observations and reanalysis back to 1765, shows that autumn RKE doubled in 1991-2013 (˜2 MJ m-2) compared to 1948-1990 (˜1 MJ m-2). A shift eastward is underway, which includes southern and northern portions of the country. Analyzing the long-running England and Wales precipitation series, we conclude that it is likely that increased precipitation amounts associated with more frequent convective storms created conditions for higher energy events.
Ghotra, Harjit Singh; Kant, Niti
2016-05-01
Electron injected in the path of a circularly polarized Gaussian laser beam under the influence of an external axial magnetic field is shown to be accelerated with a several GeV of energy in vacuum. A small angle of injection δ with 0 ∘ propagation of laser pulse is suggested for better trapping of electron in laser field and stronger betatron resonance under the influence of axial magnetic field. Such an optimized electron injection with axial magnetic field maximizes the acceleration gradient and electron energy gain with low electron scattering.
Ghotra, Harjit Singh; Kant, Niti
2016-05-01
Electron injected in the path of a circularly polarized Gaussian laser beam under the influence of an external axial magnetic field is shown to be accelerated with a several GeV of energy in vacuum. A small angle of injection δ with 0 ∘ < δ < 20 ∘ for a sideway injection of electron about the axis of propagation of laser pulse is suggested for better trapping of electron in laser field and stronger betatron resonance under the influence of axial magnetic field. Such an optimized electron injection with axial magnetic field maximizes the acceleration gradient and electron energy gain with low electron scattering.
Meneveau, Charles
2015-11-01
A topic that elicited the interest of John Lumley is pressure transport in turbulence. In 1978 (JL, in Advances in Applied Mechanics, pages 123-176) he showed that pressure transport likely acts in the opposite direction to the spatial flux of kinetic energy due to triple velocity correlations. Here we examine a flow in which the interplay of turbulent decay and spatial transport is particularly relevant. Specifically, using a specially designed active grid and screens placed in the Corrsin wind tunnel, such a flow is realized. Data are acquired using X-wire thermal anemometry at different spanwise and downstream locations. In order to resolve the dissipation rate accurately, measurements are also acquired using the NSTAP probe developed and manufactured by Princeton researchers and kindly provided to us (M. Hultmark, Y. Fan, L. Smits). The results show power-law decay with downstream distance, with a decay exponent that becomes larger in the high kinetic energy side of the flow. Measurements of the dissipation enable us to obtain the spanwise gradient of the spatial flux. One possible explanation for the observations is upgrading transport of kinetic energy due to pressure-velocity correlations, although its magnitude required to close the budget appears very large. Absence of simultaneous pressure velocity measurement preclude us to fully elucidate the observed trends. In collaboration with Adrien Thormann, Johns Hopkins University. Financial support: National Science Foundation.
International Nuclear Information System (INIS)
A range of analytical and numerical models is available to investigate the thermal behaviour of vertical ground heat exchangers, both in the short- and long-term. However, most of them ignore the thermal effects of weather at ground level that affect the upper part of boreholes. Furthermore, few models look at the integrated simulation of a ground source heat pump system for both the borehole field and heat pump. Consequently, a limited number of applications to real cases are available for designers. This paper shows a study to assess the effects of both axial heat transfer in boreholes and the weather at ground level on the fluid temperature in the boreholes, as well as on the energy efficiency of the heat pump. To this purpose, long-term analysis of two ground source heat pump systems was conducted over ten years by means of a detailed numerical simulation tool. The systems were for two office buildings with unbalanced load profiles in Canada and Italy. These case studies were analyzed as they were being designed, then the influence of the borehole arrangement and borehole length was also investigated. The simulation results show that axial heat transfer affects fluid temperature in the boreholes and the seasonal energy efficiency of the whole system more than the weather. Moreover, when the load profile is unbalanced, neglecting the effect of weather does not always ensure a conservative design of the borehole field. - Highlights: • Multi-year integrated simulations of two real GSHP systems are carried out. • The work focuses on the long-term energy efficiency of GSHP systems. • The simulation tool considers both the borehole field and the heat pump. • The axial heat transfer in the ground affects the energy efficiency of the system. • The weather at the ground level affects the fluid temperature in the boreholes
Biomineralization mechanisms: a kinetics and interfacial energy approach
Nancollas, George H.; Wu, Wenju
2000-04-01
The calcium phosphates and oxalates are among the most frequently encountered biomineral phases and numerous kinetics studies have been made of their crystallization and dissolution in supersaturated and undersaturated solutions, respectively. These have focused mainly on parameters such as solution composition, ionic strength, pH, temperature, and solid surface characteristics. There is considerable interest in extending such studies to solutions more closely simulating the biological milieu. The constant composition method is especially useful for investigating the mechanisms of these reactions, and in the present work, the interfacial tensions between water and each of these surfaces have been calculated from measured contact angles using surface tension component theory. Values for the calcium phosphate phases such as dicalcium phosphate dihydrate (DCPD), octacalcium phosphate (OCP), hydroxyapatite (HAP), and fluorapatite (FAP) may be compared with data calculated from dissolution kinetics experiments invoking different reaction mechanisms. Agreement between the directly measured interfacial energies and those calculated from the kinetics experiments provides valuable corroborative information about individual growth and dissolution mechanisms. For the calcium phosphates, the much smaller interfacial tensions of OCP and DCPD in contact with water as compared with those of HAP and FAP support the suggestion that the former phases are precursors in HAP and FAP biomineralization. The ability of a surface to nucleate mineral phases is closely related to the magnitude of the interfacial energies. Constant composition studies have also shown that HAP is an effective nucleator of calcium oxalate monohydrate, both of which are frequently observed in renal stones.
Momentum and Kinetic Energy Before the Tackle in Rugby Union
Directory of Open Access Journals (Sweden)
Sharief Hendricks, David Karpul, Mike Lambert
2014-09-01
Full Text Available Understanding the physical demands of a tackle in match situations is important for safe and effective training, developing equipment and research. Physical components such as momentum and kinetic energy, and it relationship to tackle outcome is not known. The aim of this study was to compare momenta between ball-carrier and tackler, level of play (elite, university and junior and position (forwards vs. backs, and describe the relationship between ball-carrier and tackler mass, velocity and momentum and the tackle outcome. Also, report on the ball-carrier and tackler kinetic energy before contact and the estimated magnitude of impact (energy distributed between ball-carrier and tackler upon contact. Velocity over 0.5 seconds before contact was determined using a 2-dimensional scaled version of the field generated from a computer alogorithm. Body masses of players were obtained from their player profiles. Momentum and kinetic energy were subsequently calculated for 60 tackle events. Ball-carriers were heavier than the tacklers (ball-carrier 100 ± 14 kg vs. tackler 93 ± 11 kg, d = 0.52, p = 0.0041, n = 60. Ball-carriers as forwards had a significantly higher momentum than backs (forwards 563 ± 226 Kg.m.s-1 n = 31 vs. backs 438 ± 135 Kg.m.s-1, d = 0.63, p = 0.0012, n = 29. Tacklers dominated 57% of tackles and ball-carriers dominated 43% of tackles. Despite the ball-carrier having a mass advantage before contact more frequently than the tackler, momentum advantage and tackle dominance between the ball-carrier and tackler was proportionally similar. These findings may reflect a characteristic of the modern game of rugby where efficiently heavier players (particularly forwards are tactically predetermined to carry the ball in contact.
Oil shale pyrolysis kinetics and variable activation energy principle
Energy Technology Data Exchange (ETDEWEB)
Al-Ayed, Omar S. [Faculty of Engineering Technology, Department of Chemical Engineering, P.O. Box 15008, Marka 11134 (Jordan); Matouq, M.; Anbar, Z.; Khaleel, Adnan M. [Faculty of Engineering Technology, Department of Chemical Engineering, P.O. Box 15008, Marka 11134 (Jordan); Department of Basic Sciences, Prince Abdullah Bin-Ghazi of Science and Information, Al-Balqa Applied University (Jordan); Abu-Nameh, Eyad [Department of Basic Sciences, Prince Abdullah Bin-Ghazi of Science and Information, Al-Balqa Applied University (Jordan)
2010-04-15
A modified first order kinetic equation with variable activation energy is employed to model the total weight loss of Ellajjun oil shale samples. Fixed bed retort with 400 g of oil shale sample size is used in this study in 350-550 C temperature range. Variable heating rate, h, in the range 2.6-5 C min{sup -1} are tested. Activation energy was allowed to vary as a function of oil shale conversion. The value of the activation energy increased from 98 to 120 kJ mol{sup -1} while the corresponding frequency factor changed from 9.51 x 10{sup 5} to 1.16 x 10{sup 6}. Fischer Assay analysis of the studied samples indicated 12.2 wt.% oil content. The oil shale decomposition ranged from 3.2% to 28.0%. The obtained kinetic data are modeled using variable heating rate, pyrolysis temperature and variable activation energy principle in a nitrogen sweeping medium. Good fit to the obtained experimental data is achieved. (author)
Momentum and kinetic energy before the tackle in rugby union.
Hendricks, Sharief; Karpul, David; Lambert, Mike
2014-09-01
Understanding the physical demands of a tackle in match situations is important for safe and effective training, developing equipment and research. Physical components such as momentum and kinetic energy, and it relationship to tackle outcome is not known. The aim of this study was to compare momenta between ball-carrier and tackler, level of play (elite, university and junior) and position (forwards vs. backs), and describe the relationship between ball-carrier and tackler mass, velocity and momentum and the tackle outcome. Also, report on the ball-carrier and tackler kinetic energy before contact and the estimated magnitude of impact (energy distributed between ball-carrier and tackler upon contact). Velocity over 0.5 seconds before contact was determined using a 2-dimensional scaled version of the field generated from a computer alogorithm. Body masses of players were obtained from their player profiles. Momentum and kinetic energy were subsequently calculated for 60 tackle events. Ball-carriers were heavier than the tacklers (ball-carrier 100 ± 14 kg vs. tackler 93 ± 11 kg, d = 0.52, p = 0.0041, n = 60). Ball-carriers as forwards had a significantly higher momentum than backs (forwards 563 ± 226 Kg(.)m(.)s(-1) n = 31 vs. backs 438 ± 135 Kg(.)m(.)s(-1), d = 0.63, p = 0.0012, n = 29). Tacklers dominated 57% of tackles and ball-carriers dominated 43% of tackles. Despite the ball-carrier having a mass advantage before contact more frequently than the tackler, momentum advantage and tackle dominance between the ball-carrier and tackler was proportionally similar. These findings may reflect a characteristic of the modern game of rugby where efficiently heavier players (particularly forwards) are tactically predetermined to carry the ball in contact. Key PointsFirst study to quantify momentum, kinetic energy, and magnitude of impact in rugby tackles across different levels in matches without a device attached to a player.Physical components alone, of either ball
Energy dissipation in magnetic null points at kinetic scales
Olshevsky, Vyacheslav; Eriksson, Elin; Markidis, Stefano; Lapenta, Giovanni
2015-01-01
We use kinetic particle-in-cell and magnetohydrodynamic simulations supported by an observational dataset to investigate magnetic reconnection in clusters of null points in space plasma. The magnetic configuration under investigation is driven by fast adiabatic flux rope compression that dissipates almost half of the initial magnetic field energy. In this phase powerful currents are excited producing secondary instabilities, and the system is brought into a state of `intermittent turbulence' within a few ion gyro-periods. Reconnection events are distributed all over the simulation domain and energy dissipation is rather volume-filling. Numerous spiral null points interconnected via their spines form null lines embedded into magnetic flux ropes; null point pairs demonstrate the signatures of torsional spine reconnection. However, energy dissipation mainly happens in the shear layers formed by adjacent flux ropes with oppositely directed currents. In these regions radial null pairs are spontaneously emerging an...
Entropy perturbations in assisted dark energy with mixed kinetic terms
Karwan, Khamphee
2010-01-01
We study the effects of entropy perturbations in the two fields assisted dark energy model on the density perturbations in the universe. Based on usual scenario of assisted dark energy, in which one scalar field is subdominant compared with the other in the early epoch, we show that the entropy perturbations in this two scalar field system can be constant in the early epoch and hence survive until the present epoch for a generic evolution of both fields during the radiation and matter eras. This behaviour of the entropy perturbations is preserved even when the fields are coupled via kinetic interaction. The entropy perturbations can enhance the integrated Sachs-Wolfe (ISW) effect if the signs of the contributions from entropy perturbations and curvature perturbations are opposite during dark energy domination, otherwise the ISW contribution is suppressed or changes sign. For canonical scalar field the effect of entropy perturbations on ISW effect is small because the initial value of the entropy perturbations...
Autoionization rate constants of zero electron kinetic energy Rydberg states
International Nuclear Information System (INIS)
Highlights: ► Rovibrational autoionization rate constants for diatomic molecules. ► Density matrix formulation based on the model of IBOA. ► Quantum number and energy dependences are studied. - Abstract: We have calculated the vibrational and rotational autoionization rate constants for diatomic molecules H2, N2, and HCl in high Rydberg states by employing the density matrix formulation with the inverse Born–Oppenheimer approximation basis set. The purpose is to simulate the main radiationless processes occurring in zero electron kinetic energy (ZEKE) spectroscopy. The quantum numbers and the energy dependences of the calculated autoionization rate constants are represented as the scaling laws via nonlinear regression. These data provide a suitable starting point for quantitative study of the intricate dynamics involved in ZEKE Rydberg states.
Army hypersonic compact kinetic-energy missile laser window design
Russell, Gerald W.; Cayson, Stephen C.; Jones, Michael M.; Carriger, Wendy; Mitchell, Robert R.; Strobel, Forrest A.; Rembert, Michael; Gibson, David A.
2003-09-01
The U.S. Army Aviation and Missile Command, Aviation and Missile Research, Engineering, and Development Center (AMRDEC) is currently developing the Compact Kinetic Energy Missile (CKEM) which achieves hypersonic velocities at sea level. The system incorporates guidance to the target and requires active guidance technology. CKEM's kinetic energy warhead requires an accurate guidance sub-system in order to achieve high probability of kills at long range. Due to the severity of the aerothermal environments, minimized reaction time for small time to target conditions, and the communication degrading effects of the missile's energetic boost motor, a state of the art guidance technique is being developed by the AMRDEC Missile Guidance Directorate called Side-Scatter Laser Beam Rider. This technology incorporates a 1.06 micron laser to receive an off-axis laser guidance link to communicate guidance information from the launch site to the missile. This concept requires the use of optical windows on board the missile for the missile-borne laser energy signal receivers. The current concept utilizes four rectangular windows at 90° increments around the missile. The peak velocity during flight can reach approximately 6300 ft/sec inducing severe aerothermal heating and highly transient thermal gradients. The Propulsion and Structures Directorate was tasked to design and experimentally validate the laser window. Additionally, flight tests were conducted to demonstrate the laser guidance technology. This paper will present the laser window design development process as well as aerothermal testing to induce flight like environments and assess worst case thermostructural conditions.
Extending Newton's law from nonlocal-in-time kinetic energy
International Nuclear Information System (INIS)
We study a new equation of motion derived from a context of classical Newtonian mechanics by replacing the kinetic energy with a form of nonlocal-in-time kinetic energy. It leads to a hypothetical extension of Newton's second law of motion. In a first stage the obtainable solution form is studied by considering an unknown value for the nonlocality time extent. This is done in relation to higher-order Euler-Lagrange equations and a Hamiltonian framework. In a second stage the free particle case and harmonic oscillator case are studied and compared with quantum mechanical results. For a free particle it is shown that the solution form is a superposition of the classical straight line motion and a Fourier series. We discuss the link with quanta interpretations made in Pais-Uhlenbeck oscillators. The discrete nature emerges from the continuous time setting through application of the least action principle. The harmonic oscillator case leads to energy levels that approximately correspond to the quantum harmonic oscillator levels. The solution to the extended Newton equation also admits a quantization of the nonlocality time extent, which is determined by the classical oscillator frequency. The extended equation suggests a new possible way for understanding the relationship between classical and quantum mechanics
CONSERVATIVE CASCADE OF KINETIC ENERGY IN COMPRESSIBLE TURBULENCE
International Nuclear Information System (INIS)
The physical nature of compressible turbulence is of fundamental importance in a variety of astrophysical settings. We investigate the question: 'At what scales does the mechanism of pressure-dilatation operate?' and present the first direct evidence that mean kinetic energy cascades conservatively beyond a transitional 'conversion' scale range despite not being an invariant of the dynamics. We use high-resolution 10243 subsonic and transonic simulations. The key quantity we measure is the pressure-dilatation cospectrum, EPD(k), where we show that it decays at a rate faster than k–1 in wavenumber in at least the subsonic and transonic regimes. This is sufficient to imply that mean pressure-dilatation acts primarily at large scales and that kinetic and internal energy budgets statistically decouple beyond a transitional scale range. However, we observe that small-scale dynamics remains highly compressible locally in space and that the statistical decoupling in the energy budgets is unrelated to the existence of a subsonic scale range. Our results suggest that an extension of Kolmogorov's inertial-range theory to compressible turbulence is possible.
About total kinetic energy distribution between fragments of binary fission
International Nuclear Information System (INIS)
At the investigation of binary fission reactions one of the main characteristic of process is total kinetic energy (TKE) of fission fragments and it distribution between them. From the values of these characteristics it is possible to extract the information about structure of fission fragments in the break up point of initial fissionable nuclear system. In our work TKE dependence from the deformation parameters of shape and density distribution of charge in the fission fragments are investigated. In the end of paper some generalizations of obtaining results are carried out and presented in the form of tables and figures
Quieting the Flows in Valves Using Kinetic Energy Degraders
Pluviose, Michel
2013-01-01
It’s common knowledge that nature is a subtle mixture of order and disorder. On a windless day, everything seems calm, and yet billions and billions of molecules are constantly moving and colliding in the microscopic world. We are oblivious to all this activity and believe we are safe. Then the wind picks up. It possesses kinetic energy that we can partially capture in wind turbines. Sometimes, violent gusts and gale force winds begin to blow, destroying houses and damaging nature in their pa...
Flywheels for Low-Speed Kinetic Energy Storage Systems
International Nuclear Information System (INIS)
A brief overview of different steel disc-type flywheels is presented. It contents the analysis of relationship between stress-state and kinetic energy of rotating body, comparison of the main characteristics of flywheels and description of their optimization procedures. It is shown that pro files of the discs calculated on a basis of plane stress-state assumption may be considered only as a starting point for its further improvement using 3-D approach. The aim of the review is to provide a designer for a insight into problem of shaping of steel flywheels. (Author) 19 refs
Flywheels for Low-Speed Kinetic Energy Storage Systems
Energy Technology Data Exchange (ETDEWEB)
Portnov, G.; Cruz, I.; Arias, F.; Fiffe, R. P.
2003-07-01
A brief overview of different steel disc-type flywheels is presented. It contents the analysis of relationship between stress-state and kinetic energy of rotating body, comparison of the main characteristics of flywheels and description of their optimization procedures. It is shown that profiles of the discs calculated on a basis of plane stress-state assumption may be considered only as a starting point for its further improvement using 3-D approach. The aim of the review is to provide a designer for a insight into problem of shaping of steel flywheels. (Author) 19 refs.
Intermediate-high energy nuclear reaction kinetics simulation and QMD
International Nuclear Information System (INIS)
The main features of the IHENRKS and its application in the study of thermalization for reaction of 830 MeV P + 56Fe are described. IHENRKS is the abbreviation of intermediate-high energy nuclear reaction kinetic simulation. It combines the idea and method of MCM, SSIENC and QMD. These kind of models treat the movement of each particle (nucleon and meson) and their collisions in time and space and concern with the new particle production. From calculations for 830 MeV proton bombarding reactions, it can be concluded that the nucleus is not wholly thermalized, but locally thermalized. (1 fig.)
Molecular partitioning based on the kinetic energy density
Noorizadeh, Siamak
2016-05-01
Molecular partitioning based on the kinetic energy density is performed to a number of chemical species, which show non-nuclear attractors (NNA) in their gradient maps of the electron density. It is found that NNAs are removed using this molecular partitioning and although the virial theorem is not valid for all of the basins obtained in the being used AIM, all of the atoms obtained using the new approach obey this theorem. A comparison is also made between some atomic topological parameters which are obtained from the new partitioning approach and those calculated based on the electron density partitioning.
Spectral Energy Transfer and Dissipation of Magnetic Energy from Fluid to Kinetic Scales
Bowers, K.; Li, H.
2007-01-01
We investigate the magnetic energy transfer from the fluid to kinetic scales and dissipation processes using three-dimensional fully kinetic particle-in-cell plasma simulations. The nonlinear evolution of a sheet pinch is studied where we show that it exhibits both fluid scale global relaxation and kinetic scale collisionless reconnection at multiple resonant surfaces. The interactions among collisionless tearing modes destroy the original flux surfaces and produce stochastic fields, along with generating sheets and filaments of intensified currents. In addition, the magnetic energy is transferred from the original shear length scale both to the large scales due to the global relaxation and to the smaller, kinetic scales for dissipation. The dissipation is dominated by the thermal or pressure effect in the generalized Ohm’s law, and electrons are preferentially accelerated.
Signatures for axial chromodynamics
International Nuclear Information System (INIS)
Within the context of basic left-right symmetry and the hypothesis of unification of weak, electromagnetic and strong forces at a mass level approximately equal to 104-106 GeV, relatively light ''mass'' axial gluons, confined or liberated, must be postulated. The authors remark that the existence of such ''light'' axial gluons supplementing the familiar vector octet preserves the successes of QCD, both for deep inelastic processes and charmonium physics. Through the characteristic spin-spin force, generated by their exchange, they may even help resolve some of the discrepancies between vector QCD predictions and charmonium physics. The main remark of this note is that if colour is liberated, not only vector but also axial-vector gluons are produced in high-energy e-e+ experiments, e.g. at PETRA and PEP, with fairly large cross-section. Distinctive decay modes of such liberated axial gluons are noted
Mass, momentum and kinetic energy of a relativistic particle
International Nuclear Information System (INIS)
A rigorous definition of mass in special relativity, proposed in a recent paper, is recalled and employed to obtain simple and rigorous deductions of the expressions of momentum and kinetic energy for a relativistic particle. The whole logical framework appears as the natural extension of the classical one. Only the first, second and third laws of non-relativistic classical dynamics are postulated, in an axiomatic form which does not employ the concept of force. The axiomatic statements of the second and third laws of relativistic dynamics, which yield the relativistic definitions of mass and four-momentum and the conservation of four-momentum for an isolated pair of relativistic particles with a small relative velocity, are proved as simple consequences of the classical ones and of the Lorentz transformation of coordinates. Then, relativistic four-force and three-force are defined, and the expression of relativistic kinetic energy is deduced. Finally, a simple proof of the Lorentz invariance of the conservation of the sum of four-momenta for any set of particles, with arbitrary relative velocities, is presented.
Kinetic energy for the nuclear Yang-Mills collective model
Rosensteel, George; Sparks, Nick
2015-10-01
The Bohr-Mottelson-Frankfurt model of nuclear rotations and quadrupole vibrations is a foundational model in nuclear structure physics. The model, also called the geometrical collective model or simply GCM, has two hidden mathematical structures, one Lie group theoretic and the other differential geometric. Although the group structure has been understood for some time, the geometric structure is a new unexplored feature that shares the same mathematical origin as Yang-Mills, viz., a vector bundle with a non-abelian structure group and a connection. Using the de Rham Laplacian ▵ = * d * d from differential geometry for the kinetic energy extends significantly the physical scope of the GCM model. This Laplacian contains a ``magnetic'' term due to the coupling between base manifold rotational and fiber vorticity degrees of freedom. When the connection specializes to irrotational flow, the Laplacian reduces to the Bohr-Mottelson kinetic energy operator. More generally, the connection yields a moment of inertia that is intermediate between the extremes of irrotational flow and rigid body motion.
The conservative cascade of kinetic energy in compressible turbulence
Aluie, Hussein; Li, Hui
2011-01-01
The physical nature of compressible turbulence is of fundamental importance in a variety of astrophysical settings. We present the first direct evidence that mean kinetic energy cascades conservatively beyond a transitional "conversion" scale-range despite not being an invariant of the compressible flow dynamics. We use high-resolution three-dimensional simulations of compressible hydrodynamic turbulence on $512^3$ and $1024^3$ grids. We probe regimes of forced steady-state isothermal flows and of unforced decaying ideal gas flows. The key quantity we measure is pressure dilatation cospectrum, $E^{PD}(k)$, where we provide the first numerical evidence that it decays at a rate faster than $k^{-1}$ as a function of wavenumber. This is sufficient to imply that mean pressure dilatation acts primarily at large-scales and that kinetic and internal energy budgets statistically decouple beyond a transitional scale-range. Our results suggest that an extension of Kolmogorov's inertial-range theory to compressible turbu...
Reaction kinetics of annealing of high energy implantation by XRD
International Nuclear Information System (INIS)
The annealing of structural defects caused by high energy implantation is studied using X-ray diffraction. The implanted sample (dose: 1 x 1014 ions/cm2) was isochronally annealed in flowing nitrogen in steps of 50 K up to 823 K for 10 min each, using a RTA system developed in Mumbai University. XRD patterns were recorded after each annealing and analyzed for strain and curvature. Also, the screw dislocation density was estimated at each stage of annealing using the FWHM of w scans in high resolution mode. The XRD profiles were simulated using the dynamical theory of X-ray diffraction for layer damage i.e. thickness, mismatch with respect to substrate, Debye Waller factor and sample curvature. The activation energy and characteristic temperature of annealing were estimated through reaction kinetics, utilizing the experimental XRD for progressive changes with temperature, of strain and dislocation density
On a Broken Formal Symmetry between Kinetic and Gravitational Energy
Shirazi, Armin Nikkhah
2010-01-01
Historically, the discovery of symmetries has played an important role in the progress of our fundamental understanding of nature. This paper will demonstrate that there exists in Newtonian theory in a spherical gravitational field a formal symmetry between the kinetic (KE) and gravitational potential energy (GPE) of a test mass. Put differently, there exists a way of expressing GPE such that the form of the mathematical expression remains invariant under an interchange of KE and GPE. When extended to relativity by a suitable assumption, it leads to a framework that bridges the general relativistic and Newtonian conceptions of gravitational energy, even though the symmetry is broken except in the infinitesimal limit. Recognizing this symmetry at infinitesimal scales makes it possible to write a relativistic equation of an individual graviton, the properties of which under under one interpretation may be unexpected.
A rotational and axial motion system load frame insert for in situ high energy x-ray studies
International Nuclear Information System (INIS)
High energy x-ray characterization methods hold great potential for gaining insight into the behavior of materials and providing comparison datasets for the validation and development of mesoscale modeling tools. A suite of techniques have been developed by the x-ray community for characterizing the 3D structure and micromechanical state of polycrystalline materials; however, combining these techniques with in situ mechanical testing under well characterized and controlled boundary conditions has been challenging due to experimental design requirements, which demand new high-precision hardware as well as access to high-energy x-ray beamlines. We describe the design and performance of a load frame insert with a rotational and axial motion system that has been developed to meet these requirements. An example dataset from a deforming titanium alloy demonstrates the new capability
Kinetic Energy of Tornadoes in the United States.
Directory of Open Access Journals (Sweden)
Tyler Fricker
Full Text Available Tornadoes can cause catastrophic destruction. Here total kinetic energy (TKE as a metric of destruction is computed from the fraction of the tornado path experiencing various damage levels and a characteristic wind speed for each level. The fraction of the path is obtained from a model developed for the Nuclear Regulatory Commission that combines theory with empirical data. TKE is validated as a useful metric by comparing it to other indexes and loss indicators. Half of all tornadoes have TKE exceeding 62.1 GJ and a quarter have TKE exceeding 383.2 GJ. One percent of the tornadoes have TKE exceeding 31.9 TJ. April has more energy than May with fewer tornadoes; March has more energy than June with half as many tornadoes. September has the least energy but November and December have the fewest tornadoes. Alabama ranks number one in terms of tornado energy with 2.48 PJ over the period 2007-2013. TKE can be used to help better understand the changing nature of tornado activity.
Kinetic Energy of Tornadoes in the United States.
Fricker, Tyler; Elsner, James B
2015-01-01
Tornadoes can cause catastrophic destruction. Here total kinetic energy (TKE) as a metric of destruction is computed from the fraction of the tornado path experiencing various damage levels and a characteristic wind speed for each level. The fraction of the path is obtained from a model developed for the Nuclear Regulatory Commission that combines theory with empirical data. TKE is validated as a useful metric by comparing it to other indexes and loss indicators. Half of all tornadoes have TKE exceeding 62.1 GJ and a quarter have TKE exceeding 383.2 GJ. One percent of the tornadoes have TKE exceeding 31.9 TJ. April has more energy than May with fewer tornadoes; March has more energy than June with half as many tornadoes. September has the least energy but November and December have the fewest tornadoes. Alabama ranks number one in terms of tornado energy with 2.48 PJ over the period 2007-2013. TKE can be used to help better understand the changing nature of tornado activity. PMID:26132830
Kinetic energy sum spectra in nonmesonic weak decay of hypernuclei
International Nuclear Information System (INIS)
We evaluate the coincidence spectra in the nonmesonic weak decay (NMWD) ΛN→nN of Λ hypernuclei Λ4He, Λ5He, Λ12C, Λ16O, and Λ28Si, as a function of the sum of kinetic energies EnN=En+EN for N=n,p. The strangeness-changing transition potential is described by the one-meson-exchange model, with commonly used parametrization. Two versions of the independent-particle shell model (IPSM) are employed to account for the nuclear structure of the final residual nuclei. They are as follows: (a) IPSM-a, where no correlation, except for the Pauli principle, is taken into account and (b) IPSM-b, where the highly excited hole states are considered to be quasistationary and are described by Breit-Wigner distributions, whose widths are estimated from the experimental data. All np and nn spectra exhibit a series of peaks in the energy interval 110 MeV nN-1 , going from congruent with 4 MeV for Λ28Si to congruent with 40 MeV for Λ4He. Such a description could be pretty fair for the light Λ4He and Λ5He hypernuclei. For the remaining, heavier, hypernuclei it is very important, however, to consider as well the spreading in strength of the deep-hole states and bring into play the IPSM-b approach. Notwithstanding the nuclear model that is employed the results depend only very weakly on the details of the dynamics involved in the decay process proper. We propose that the IPSM is the appropriate lowest-order approximation for the theoretical calculations of the of kinetic energy sum spectra in the NMWD. It is in comparison to this picture that one should appraise the effects of the final-state interactions and of the two-nucleon-induced decay mode
Functional derivative of the kinetic energy functional for spherically symmetric systems.
Nagy, Á
2011-07-28
Ensemble non-interacting kinetic energy functional is constructed for spherically symmetric systems. The differential virial theorem is derived for the ensemble. A first-order differential equation for the functional derivative of the ensemble non-interacting kinetic energy functional and the ensemble Pauli potential is presented. This equation can be solved and a special case of the solution provides the original non-interacting kinetic energy of the density functional theory. PMID:21806089
Isospin-invariant Skyrme energy-density-functional approach with axial symmetry
Sheikh, J A; Dobaczewski, J; Nakatsukasa, T; Nazarewicz, W; Sato, K
2014-01-01
We develop the isospin-invariant Skyrme-EDF method by considering local densities in all possible isospin channels and proton-neutron (p-n) mixing terms as mandated by the isospin symmetry. The EDF employed has the most general form that depends quadratically on the isoscalar and isovector densities. We test and benchmark the resulting p-n EDF approach, and study the general properties of the new scheme by means of the cranking in the isospin space. We extend the existing axial DFT solver HFBTHO to the case of isospin-invariant EDF approach with all possible p-n mixing terms. Explicit expressions have been derived for all the densities and potentials that appear in the isospin representation. In practical tests, we consider the Skyrme EDF SkM* and, as a first application, concentrate on Hartree-Fock aspects of the problem, i.e., pairing has been disregarded. Calculations have been performed for the (A=78, T~11), (A=40, T~8), and (A=48, T~4) isobaric analog chains. Isospin structure of self-consistent p-n mixe...
An integral turbulent kinetic energy analysis of free shear flows
Peters, C. E.; Phares, W. J.
1973-01-01
Mixing of coaxial streams is analyzed by application of integral techniques. An integrated turbulent kinetic energy (TKE) equation is solved simultaneously with the integral equations for the mean flow. Normalized TKE profile shapes are obtained from incompressible jet and shear layer experiments and are assumed to be applicable to all free turbulent flows. The shear stress at the midpoint of the mixing zone is assumed to be directly proportional to the local TKE, and dissipation is treated with a generalization of the model developed for isotropic turbulence. Although the analysis was developed for ducted flows, constant-pressure flows were approximated with the duct much larger than the jet. The axisymmetric flows under consideration were predicted with reasonable accuracy. Fairly good results were also obtained for the fully developed two-dimensional shear layers, which were computed as thin layers at the boundary of a large circular jet.
Mass independent kinetic energy reducing inlet system for vacuum environment
Reilly, Peter T. A. [Knoxville, TN
2010-12-14
A particle inlet system comprises a first chamber having a limiting orifice for an incoming gas stream and a micrometer controlled expansion slit. Lateral components of the momentum of the particles are substantially cancelled due to symmetry of the configuration once the laminar flow converges at the expansion slit. The particles and flow into a second chamber, which is maintained at a lower pressure than the first chamber, and then moves into a third chamber including multipole guides for electromagnetically confining the particle. The vertical momentum of the particles descending through the center of the third chamber is minimized as an upward stream of gases reduces the downward momentum of the particles. The translational kinetic energy of the particles is near-zero irrespective of the mass of the particles at an exit opening of the third chamber, which may be advantageously employed to provide enhanced mass resolution in mass spectrometry.
International Nuclear Information System (INIS)
The eigenfrequencies of the axial w-modes of oscillating neutron stars are studied using the continued fraction method with an equation of state (EOS) partially constrained by the recent terrestrial nuclear laboratory data. It is shown that the density dependence of the nuclear symmetry energy Esym(ρ) affects significantly both the frequencies and the damping times of these modes. Besides confirming the previously found universal behavior of the mass-scaled eigenfrequencies as functions of the compactness of neutron stars, we explored several alternative universal scaling functions. Moreover, the wII-mode is found to exist only for neutron stars having a compactness of M/R≥0.1078 independent of the EOS used.
Trajectory-dependent energy loss for swift He atoms axially scattered off a silver surface
International Nuclear Information System (INIS)
Angle- and energy-loss-resolved distributions of helium atoms grazingly scattered from a Ag(110) surface along low indexed crystallographic directions are investigated considering impact energies in the few keV range. Final projectile distributions are evaluated within a semi-classical formalism that includes dissipative effects due to electron–hole excitations through a friction force. For mono-energetic beams impinging along the [11¯0],[11¯2] and [001] directions, the model predicts the presence of multiple peak structures in energy-loss spectra. Such structures provide detailed information about the trajectory-dependent energy loss. However, when the experimental dispersion of the incident beam is taken into account, these energy-loss peaks are completely washed out, giving rise to a smooth energy-loss distribution, in fairly good agreement with available experimental data
International Nuclear Information System (INIS)
In early work, Dawson and March [J. Chem. Phys. 81, 5850 (1984)] proposed a local energy method for treating both Hartree-Fock and correlated electron theory. Here, an exactly solvable model two-electron atom with pure harmonic interactions is treated in its ground state in the above context. A functional relation between the kinetic energy density t(r) at the origin r=0 and the electron density p(r) at the same point then emerges. The same approach is applied to the Hookean atom; in which the two electrons repel with Coulombic energy e2/r12, with r12 the interelectronic separation, but are still harmonically confined. Again the kinetic energy density t(r) is the focal point, but now generalization away from r=0 is also effected. Finally, brief comments are added about He-like atomic ions in the limit of large atomic number. (author)
Orientational, kinetic, and magnetic energy of geodynamo, reversals, and asymmetries
Starchenko, S. V.
2015-07-01
Integral laws describing the evolution of the kinetic, magnetic, and orientational energy in the liquid core of the Earth, which are also valid in the interiors of the other terrestrial planets, are derived, simplified, and analyzed. These laws are coarsely approximated by a system of ordinary differential equations with a given energy of the convection. The characteristic velocities, magnetic fields, periods, and scales as the functions of the power of the convection are estimated for the states beyond and close to the reversal or excursion. With the assumed simplifications, the convection power should be close to a certain value in order to enable a relatively short reversal or excursion; significant deviation of the convection energy from this value will render the system into a long-term steady state. Here, two types of steady state are possible: the codirectional state with the magnetic field oriented along the velocity vector, and contradirectional state with the opposing orientations of the magnetic field and velocity. These states are not symmetric with respect to each other since, other factors being equal, the energy support of the convection and the average intensity of the magnetic field are typically higher in the contradirectional rather than codirectional state. The total duration of codirectional states is somewhat shorter than contradirectional states in the case when the convection power grows with time; in the case of a long-decreasing convection power, the situation is opposite. This asymmetry in the duration of steady states is confirmed by the paleomagnetic data on the timescale of the magnetic reversals. The length of the average interval between the reversals is controlled by the turbulent, thermal, electromagnetic, and visco-compositional diffusion. The predominant type of the diffusion can be in many cases identified from the dependence of the reversal frequency on the intensity of the magnetic field based on the paleomagnetic data. The
Fluctuating kinetic energy budget during homogeneous flow of a fluid solid mixture
International Nuclear Information System (INIS)
Ensemble-averaging theorems are applied to derive transport equations for the fluctuating kinetic energy of a particulate mixture consisting of a continuous fluid and solid particles. The evolution of fluctuating kinetic energy in a homogeneous flow is examined and discussed. copyright 1996 American Institute of Physics
A Comparison of Kinetic Energy and Momentum in Special Relativity and Classical Mechanics
Riggs, Peter J.
2016-01-01
Kinetic energy and momentum are indispensable dynamical quantities in both the special theory of relativity and in classical mechanics. Although momentum and kinetic energy are central to understanding dynamics, the differences between their relativistic and classical notions have not always received adequate treatment in undergraduate teaching.…
A Virial Theorem for the Kinetic Energy of a Heavy Quark inside Hadrons
Neubert, Matthias(PRISMA Cluster of Excellence & Mainz Institut for Theoretical Physics, Johannes Gutenberg University, D-55099, Mainz, Germany)
1993-01-01
The formalism of the heavy quark effective theory is used to derive the field-theory analog of the virial theorem, which relates the matrix element of the kinetic energy of a heavy quark inside a hadron to a matrix element of the gluon field strength tensor. The existing QCD sum rule calculations of the kinetic energy are not consistent with this theorem.
Axial anomaly and energy dependence of hyperon polarization in Heavy-Ion Collisions
Sorin, A
2016-01-01
We address the issue of energy and charge dependence of global polarization of $\\Lambda$ hyperons in peripheral $Au-Au$ collisions recently observed by STAR collaboration at RHIC. We compare the different contributions to the anomalous mechanism relating polarization to vorticity and hydrodynamic helicity in QCD matter. We stress that the suppression of gravitational anomaly related contribution in strongly correlated matter observed in lattice simulations confirms our earlier prediction of rapid decrease of polarization with collision energy. Our mechanism leads to the polarization of $\\bar \\Lambda$ of the same sign and larger magnitude than $\\Lambda$. The energy and charge dependence of polarization is suggested as a sensitive probe of fine details of QCD matter structure.
The Rainfall and Rainfall Kinetic Energy Intensity-Duration of Landslides and Debris flow in Taiwan
Chang, Jui-Ming; Chen, Hongey
2016-04-01
This research used Joss-Waldvogel Disdrometers (JWD) which set in Shiment catchment, Northern Taiwan and Chishan catchment, Southern Taiwan to record rainfall kinetic energy data, to find the relationship between rainfall kinetic energy and rainfall intensity in these two areas. The distance between the two areas is less than 150 km. These data help the researchers and showed that the equations of relationship were ekN =28.7* (1-0.7027*exp(-0.0395*I)) and ekS=27.4*(1-0.5954*exp(-0.0345*I)). Generally, rainfall kinetic energy in Northern Taiwan is higher than in Southern Taiwan during rainfall period. Also, the occurring time and rainfall records of 143 landslide events from 2006 to 2012 were analyzed. The rainfall-intensity (I-D) relationship could be used to build rainfall threshold which were IN=15.13 D‑0.28 and IS=47.58 D‑0.35. In brief, the rainfall feature in landslide of Northern Taiwan had low rainfall intensity, long rainfall duration and low average accumulative rainfall. By combining rainfall kinetic energy and rainfall threshold, rainfall kinetic energy threshold could be established, which were ¯E N=13.83 D‑0.04 and ¯E S =15.59 D‑0.02. The results showed that not only for rainfall but also for rainfall kinetic energy threshold, the values of thresholds in North were lower than those in South. Due to impaction energy of rainfall to ground surface, rainfall kinetic energy would not forever increase. Therefore, rainfall kinetic energy threshold is also a useful tool for landslide warning. Key words: Rainfall kinetic energy, Rainfall threshold, Rainfall kinetic energy threshold, Landslide
Indian Academy of Sciences (India)
V Sridhar; D Sudarshan Reddy; N Ravikumar Reddy; S Satyanarayana
2002-02-01
Equilibria and kinetics of the reaction of bromomethyl(aquo) cobaloxime with histamine, histidine, glycine and ethyl glycine ester and iodomethyl(aquo) cobaloxime with cyanide, imidazole and substituted imidazoles were studied as a function of H at 25°C, 1.0 M ionic strength (KCl) by spectrophotometry technique. The rate of substitution of H2O varies with the of the incoming ligand, thus establishing the existence of nucleophilic participation of the ligand in the transition state. Dissociation kinetic reactions were also studied as a function of H. Binding and kinetic data were interpreted based on the basicity, steric crowd of the entering ligand and HSAB principle. To compare the rate constants of the entering ligands H independent second-order rate constants were calculated.
Control of Active Axial Magnetic Bearings for Flywheel-based Energy Storage System
Morís Gómez, Juan
2014-01-01
This thesis deals with the design and implementation of the control system for a Flywheel-based Energy Storage System (FESS) with active magnetic bearings. The thesis focuses on the construction of realistic model of the system according to experimental tests. The simulation model will be used to control the thrust magnetic bearings in order to withstand the flywheel in levitation.
Vertical-axial component wind turbine with a high coefficient using for wind energy
International Nuclear Information System (INIS)
The report presents the results of research and development on of promising wind units carousel type with a high ratio utilization of wind energy. This devices use a well-known invention – the wind turbine Darrieus. The rotation of the turbine is due to the action of ascensional power to aerodynamic well-streamlined symmetrical about the chord wing profiles of NASA, which are working wind turbine blades. The shaft rotation can be connected with the working blades of one of two ways: using the “swings” or the way “troposkino”. Darrieus turbine has a ratio utilization of wind energy xmax=045. Despite the fact that this is a good indicator of the efficiency of the turbine working, the proposed option allows us to significantly increase the value of this coefficient. The bases methodology of this research is a method of technical and technological research and development design of prospective wind energy construction (WES). Key words: wind turbine, the blade, coefficient utilization of wind energy
Study of axial magnetic effect
International Nuclear Information System (INIS)
The Axial Magnetic Effect manifests itself as an equilibrium energy flow of massless fermions induced by the axial (chiral) magnetic field. Here we study the Axial Magnetic Effect in the quenched SU(2) lattice gauge theory with massless overlap fermions at finite temperature. We numerically observe that in the low-temperature hadron phase the effect is absent due to the quark confinement. In the high-temperature deconfinement phase the energy flow is an increasing function of the temperature which reaches the predicted asymptotic T2 behavior at high temperatures. We find, however, that energy flow is about one order of magnitude lower compared to a theoretical prediction
Zero Kinetic Energy Photoelectron Spectroscopy of Benzo[h]quinoline.
Harthcock, Colin; Zhang, Jie; Kong, Wei
2015-12-17
We report zero kinetic energy (ZEKE) photoelectron spectroscopy of benzo[h]quinoline (BhQ) via resonantly enhanced multiphoton ionization (REMPI) through the first electronically excited state S1. From the simulated REMPI spectra with and without Herzberg-Teller coupling, we conclude that vibronic coupling plays a minor but observable role in the electronic excitation to the S1 state. We further compare the S1 state of BhQ with the first two electronically excited states of phenanthrene, noticing a similarity of the S1 state of BhQ with the second electronically excited state S2 of phenanthrene. In the ZEKE spectra of BhQ, the vibrational frequencies of the cationic state D0 are consistently higher than those of the intermediate neutral state, indicating enhanced bonding upon ionization. The sparse ZEKE spectra, compared with the spectrum of phenanthrene containing rich vibronic activities, further imply that the nitrogen atom has attenuated the structural change between S1 and D0 states. We speculate that the nitrogen atom can withdraw an electron in the S1 state and donate an electron in the D0 state, thereby minimizing the structural change during ionization. The origin of the first electronically excited state is determined to be 29,410 ± 5 cm(-1), and the adiabatic ionization potential is determined to be 65,064 ± 7 cm(-1). PMID:26039927
Phantom dark energy models with negative kinetic term
International Nuclear Information System (INIS)
We examine phantom dark energy models derived from a scalar field with a negative kinetic term for which V(φ)→∞ asymptotically. All such models can be divided into three classes, corresponding to an equation of state parameter wφ with asymptotic behavior wφ→-1, wφ→w0φ→-∞. We derive the conditions on the potential V(φ) which lead to each of these three types of behavior. For models with wφ→-1, we derive the conditions on V(φ) which determine whether or not such models produce a future big rip. Observational constraints are derived on two classes of these models: power-law potentials with V(φ)=λφα (with α positive or negative) and exponential potentials of the form V(φ)=βeλφα. It is shown that these models spend more time in a state with Ωm∼Ωφ than do corresponding models with a constant value of wφ, thus providing a more satisfactory solution to the coincidence problem
Bare, Simon R.; Knop-Gericke, Axel; Teschner, Detre; Hävacker, Michael; Blume, Raoul; Rocha, Tulio; Schlögl, Robert; Chan, Ally S. Y.; Blackwell, N.; Charochak, M. E.; ter Veen, Rik; Brongersma, Hidde H.
2016-06-01
The surface Si/Al ratio in a series of zeolite Y samples has been obtained using laboratory XPS, synchrotron (variable kinetic energy) XPS, and low energy ion scattering (LEIS) spectroscopy. The non-destructive depth profile obtained using variable kinetic energy XPS is compared to that from the destructive argon ion bombardment depth profile from the lab XPS instrument. All of the data indicate that the near surface region of both the ammonium form and steamed Y zeolites is strongly enriched in aluminum. It is shown that when the inelastic mean free path of the photoelectrons is taken into account the laboratory XPS of aluminosilicates zeolites does not provide a true measurement of the surface stoichiometry, while variable kinetic energy XPS results in a more surface sensitive measurement. A comprehensive Si/Al concentration profile as a function of depth is developed by combining the data from the three surface characterization techniques. The LEIS spectroscopy reveals that the topmost atomic layer is further enriched in Al compared to subsequent layers.
Energy Conservation Tests of a Coupled Kinetic-kinetic Plasma-neutral Transport Code
Energy Technology Data Exchange (ETDEWEB)
Stotler, D. P.; Chang, C. S.; Ku, S. H.; Lang, J.; Park, G.
2012-08-29
A Monte Carlo neutral transport routine, based on DEGAS2, has been coupled to the guiding center ion-electron-neutral neoclassical PIC code XGC0 to provide a realistic treatment of neutral atoms and molecules in the tokamak edge plasma. The DEGAS2 routine allows detailed atomic physics and plasma-material interaction processes to be incorporated into these simulations. The spatial pro le of the neutral particle source used in the DEGAS2 routine is determined from the uxes of XGC0 ions to the material surfaces. The kinetic-kinetic plasma-neutral transport capability is demonstrated with example pedestal fueling simulations.
Principal parametric resonance of axially accelerating rectangular thin plate in magnetic field
Institute of Scientific and Technical Information of China (English)
胡宇达; 张金志
2013-01-01
Nonlinear parametric vibration and stability is investigated for an axially accelerating rectangular thin plate subjected to parametric excitations resulting from the axial time-varying tension and axial time-varying speed in the magnetic field. Consid-ering geometric nonlinearity, based on the expressions of total kinetic energy, potential energy, and electromagnetic force, the nonlinear magneto-elastic vibration equations of axially moving rectangular thin plate are derived by using the Hamilton principle. Based on displacement mode hypothesis, by using the Galerkin method, the nonlinear para-metric oscillation equation of the axially moving rectangular thin plate with four simply supported edges in the transverse magnetic field is obtained. The nonlinear principal parametric resonance amplitude-frequency equation is further derived by means of the multiple-scale method. The stability of the steady-state solution is also discussed, and the critical condition of stability is determined. As numerical examples for an axially moving rectangular thin plate, the influences of the detuning parameter, axial speed, axial tension, and magnetic induction intensity on the principal parametric resonance behavior are investigated.
LaRue, Jerry L; Schäfer, Tim; Matsiev, Daniel; Velarde, Luis; Nahler, N Hendrik; Auerbach, Daniel J; Wodtke, Alec M
2011-12-22
We report kinetic energy distributions of exoelectrons produced by collisions of highly vibrationally excited NO molecules with a low work function Cs dosed Au(111) surface. These measurements show that energy dissipation pathways involving nonadiabatic conversion of vibrational energy to electronic energy can result in electronic excitation of more than 3 eV, consistent with the available vibrational energy. We measured the dependence of the electron energy distributions on the translational and vibrational energy of the incident NO and find a clear positive correlation between final electron kinetic energy and initial vibrational excitation and a weak but observable inverse dependence of electron kinetic energy on initial translational energy. These observations are consistent with a vibrational autodetachment mechanism, where an electron is transferred to NO near its outer vibrational turning point and ejected near its inner vibrational turning point. Within the context of this model, we estimate the NO-to-surface distance for electron transfer. PMID:22112161
Kinetic energy management in road traffic injury prevention: a call for action
Directory of Open Access Journals (Sweden)
Davoud Khorasani-Zavareh
2015-01-01
Full Text Available Abstract: By virtue of their variability, mass and speed have important roles in transferring energies during a crash incidence (kinetic energy. The sum of kinetic energy is important in determining an injury severity and that is equal to one half of the vehicle mass multiplied by the square of the vehicle speed. To meet the Vision Zero policy (a traffic safety policy prevention activities should be focused on vehicle speed management. Understanding the role of kinetic energy will help to develop measures to reduce the generation, distribution, and effects of this energy during a road traffic crash. Road traffic injury preventive activities necessitate Kinetic energy management to improve road user safety.
Universal Power Law for Relationship between Rainfall Kinetic Energy and Rainfall Intensity
Directory of Open Access Journals (Sweden)
Seung Sook Shin
2016-01-01
Full Text Available Rainfall kinetic energy has been linked to linear, exponential, logarithmic, and power-law functions using rainfall intensity as an independent variable. The power law is the most suitable mathematical expression used to relate rainfall kinetic energy and rainfall intensity. In evaluating the rainfall kinetic energy, the empirical power laws have shown a larger deviation than other functions. In this study, universal power law between rainfall kinetic energy and rainfall intensity was proposed based on the rainfall power theory under an ideal assumption that drop-size is uniformly distributed in constant rainfall intensity. An exponent of the proposed power law was 11/9 and coefficient was estimated at 10.3 from the empirical equations of the existing power-law relation. The rainfall kinetic energy calculated by universal power law showed >95% concordance rate in comparison to the average values calculated from exponential and logarithmic functions used in soil erosion model such as USLE, RUSLE, EUROSEM, and SEMMA and <5% relative difference as compared to the average rainfall kinetic energies calculated by other empirical functions. Therefore, it is expected that power law of ideal assumption may be utilized as a universal power law in evaluating rainfall kinetic energy.
Dissociation of CO induced by He2+ ions. Pt. 1: Fragmentation and kinetic energy release spectra
International Nuclear Information System (INIS)
The dissociation of COq+ ions (q ≤ 3) produced in collisions of keV amu-1 He2+ ions with CO has been studied by time-of-flight measurements. Both singles and coincidence time-of-flight techniques have been used to determine the kinetic energy release of the dissociating CO molecules. We describe the method to transform the singles and coincidence time-of-flight spectra into total kinetic energy distributions and discuss these distributions. They represent kinetic energy release distributions which clearly exhibit various contributions associated with different dissociation channels. In comparison with other ionization methods similarities but also clear differences are noted. (author)
Kinetic energy distributions of fragment ions in collisions of energetic heavy ions with C60
International Nuclear Information System (INIS)
Mass distributions of fragment ions of C60 produced in collisions with energetic heavy ions have been measured by means of time-of-flight (TOF) method. From the peak profile analysis, initial kinetic energy distributions (KED) of fragment ions were obtained. KED were investigated for three different projectiles. For all fragment ions except for C1+, KED peaked at a few eV kinetic energies. KED of C1+ was found to have a double-peak structure, indicating that the C1+ ions were produced through two different mechanisms. Also, it was found that the mean kinetic energies had strong correlation with electronic stopping cross-section. (author)
Prediction of free turbulent mixing using a turbulent kinetic energy method
Harsha, P. T.
1973-01-01
Free turbulent mixing of two-dimensional and axisymmetric one- and two-stream flows is analyzed by a relatively simple turbulent kinetic energy method. This method incorporates a linear relationship between the turbulent shear and the turbulent kinetic energy and an algebraic relationship for the length scale appearing in the turbulent kinetic energy equation. Good results are obtained for a wide variety of flows. The technique is shown to be especially applicable to flows with heat and mass transfer, for which nonunity Prandtl and Schmidt numbers may be assumed.
Institute of Scientific and Technical Information of China (English)
Chen Jian-Xin; Ma Ri; Ren Hai-Zhen; Li Xia; Wu Cheng-Yin; Yang Hong; Gong Qi-Huang
2004-01-01
@@ The kinetic energy release of fragment ions produced by the interaction of femtosecond laser pulse radiation with diatomic and linear triatomic molecules N2, CO, CO2 and CS2 is investigated. In the case of linear polarization, angles at which the kinetic energy release of ions has the maximum value are different from the alignment of molecules though the kinetic energy release of fragment atomic ions depends on the angle between the laser polarization vector and the detection axis of the time-of-flight.
Che, H.; Goldstein, M. L.; Vinas, A. F.
2014-01-01
The observed steep kinetic scale turbulence spectrum in the solar wind raises the question of how that turbulence originates. Observations of keV energetic electrons during solar quiet time suggest them as a possible source of free energy to drive kinetic turbulence. Using particle-in-cell simulations, we explore how the free energy released by an electron two-stream instability drives Weibel-like electromagnetic waves that excite wave-wave interactions. Consequently, both kinetic Alfvénic and whistler turbulence are excited that evolve through inverse and forward magnetic energy cascades.
Power Spectral Analysis of Jupiter's Clouds and Kinetic Energy from Cassini
Choi, David S; 10.1016/j.icarus.2011.10.001
2013-01-01
We present suggestive evidence for an inverse energy cascade within Jupiter's atmosphere through a calculation of the power spectrum of its kinetic energy and its cloud patterns. Using Cassini observations, we composed full-longitudinal mosaics of Jupiter's atmosphere at several wavelengths. We also utilized image pairs derived from these observations to generate full-longitudinal maps of wind vectors and atmospheric kinetic energy within Jupiter's troposphere. We computed power spectra of the image mosaics and kinetic energy maps using spherical harmonic analysis. Power spectra of Jupiter's cloud patterns imaged at certain wavelengths resemble theoretical spectra of two-dimensional turbulence, with power-law slopes near -5/3 and -3 at low and high wavenumbers, respectively. The slopes of the kinetic energy power spectrum are also near -5/3 at low wavenumbers. At high wavenumbers, however, the spectral slopes are relatively flatter than the theoretical prediction of -3. Our results also show the importance of...
Luberti, Mauro; Kim, Yo Han; Lee, Chang-Ha; Ferrari, Maria-Chiara; Ahn, Hyungwoong
2015-01-01
It was aimed to derive rigorous momentum and energy balance equations where the change of kinetic energy in both spatial and temporal domains of a fixed-bed adsorption column was newly taken into account. While the effect of kinetic energy on adsorption column dynamics is negligible in most cases, it can become more and more influential with an adsorption column experiencing a huge pressure drop or with the gas velocity changing abruptly with time and along the column. The rigorous momentum a...
Energy Technology Data Exchange (ETDEWEB)
Wakayama, Toshitaka, E-mail: wakayama@saitama-med.ac.jp; Yonemura, Motoki [School of Biomedical Engineering, Saitama Medical University, Yamane 1397-1, Hidaka, Saitama 350-1241 (Japan); Oikawa, Hiroki; Sasanuma, Atsushi; Arai, Goki; Fujii, Yusuke [Department of Electrical and Electronic Engineering, Faculty of Engineering, Utsunomiya University, Yoto 7-1-2, Utsunomiya, Tochigi 321-8585 (Japan); Dinh, Thanh-Hung; Otani, Yukitoshi [Center for Optical Research & Education (CORE), Utsunomiya University, Yoto 7-1-2, Utsunomiya, Tochigi 321-8585 (Japan); Higashiguchi, Takeshi, E-mail: higashi@cc.utsunomiya-u.ac.jp [Department of Electrical and Electronic Engineering, Faculty of Engineering, Utsunomiya University, Yoto 7-1-2, Utsunomiya, Tochigi 321-8585 (Japan); Center for Optical Research & Education (CORE), Utsunomiya University, Yoto 7-1-2, Utsunomiya, Tochigi 321-8585 (Japan); Sakaue, Kazuyuki, E-mail: kazuyuki.sakaue@aoni.waseda.jp [Waseda Institute for Advanced Study, Waseda University, 3-4-1, Okubo, Shinjuku, Tokyo 169-8555 (Japan); Washio, Masakazu [Research Institute for Science and Engineering, Waseda University, 3-4-1, Okubo, Shinjuku, Tokyo 169-8555 (Japan); Miura, Taisuke, E-mail: miura@fzu.cz [HiLASE Centre, Institute of Physics CAS, Za radnicí 828, 252 41, Dolní Břežany (Czech Republic); Takahashi, Akihiko [Department of Health Sciences, Faculty of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Fukuoka 812-8582 (Japan); Nakamura, Daisuke; Okada, Tatsuo [Graduate School of Information Sciences and Electrical Engineering, Kyushu University, 744 Motooka, Nishi, Fukuoka 819-0395 (Japan)
2015-08-24
We demonstrated the generation of the intense radially polarized mid-infrared optical vortex at a wavelength of 10.6 μm by use of a passive axially symmetric zinc selenide (ZnSe) waveplate with high energy pulse throughput. The phase of the radially polarized optical vortex with the degree of polarization of 0.95 was spirally distributed in regard to the angle. The converted laser beam energy of about 2.6 mJ per pulse was obtained at the input pulse energy of 4.9 mJ, corresponding to the energy conversion efficiency of 56%.
International Nuclear Information System (INIS)
We demonstrated the generation of the intense radially polarized mid-infrared optical vortex at a wavelength of 10.6 μm by use of a passive axially symmetric zinc selenide (ZnSe) waveplate with high energy pulse throughput. The phase of the radially polarized optical vortex with the degree of polarization of 0.95 was spirally distributed in regard to the angle. The converted laser beam energy of about 2.6 mJ per pulse was obtained at the input pulse energy of 4.9 mJ, corresponding to the energy conversion efficiency of 56%
Analysis of energy transfer in quantum networks using kinetic network approximations
Moser, David K
2012-01-01
Coherent energy transfer in pigment-protein complexes has been studied by mapping the quantum network to a kinetic network. This gives an analytic way to find parameter values for optimal transfer efficiency. In the case of the Fenna-Matthews-Olson (FMO) complex, the comparison of quantum and kinetic network evolution shows that dephasing-assisted energy transfer is driven by the two-site coherent interaction, and not system-wide coherence. Using the Schur complement, we find a new kinetic network that gives a closer approximation to the quantum network by including all multi-site coherence contributions. Our new network approximation can be expanded as a series with contributions representing different numbers of coherently interacting sites. For both kinetic networks we study the system relaxation time, the time it takes for the excitation to spread throughout the complex. We make mathematically rigorous estimates of the relaxation time when comparing kinetic and quantum network. Numerical simulations compa...
Turbulent kinetic energy balance measurements in the wake of a low-pressure turbine blade
Energy Technology Data Exchange (ETDEWEB)
Sideridis, A. [Laboratory of Fluid Mechanics and Turbomachinery, Department of Mechanical Engineering, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece); Yakinthos, K., E-mail: kyros@eng.auth.g [Laboratory of Fluid Mechanics and Turbomachinery, Department of Mechanical Engineering, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece); Goulas, A. [Laboratory of Fluid Mechanics and Turbomachinery, Department of Mechanical Engineering, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece)
2011-02-15
The turbulent kinetic energy budget in the wake generated by a high lift, low-pressure two-dimensional blade cascade of the T106 profile was investigated experimentally using hot-wire anemometry. The purpose of this study is to examine the transport mechanism of the turbulent kinetic energy and provide validation data for turbulence modeling. Point measurements were conducted on a high spatial resolution, two-dimensional grid that allowed precise derivative calculations. Positioning of the probe was achieved using a high accuracy traversing mechanism. The turbulent kinetic energy (TKE) convection, production, viscous diffusion and turbulent diffusion were all obtained directly from experimental measurements. Dissipation and pressure diffusion were calculated indirectly using techniques presented and validated by previous investigators. Results for all terms of the turbulent kinetic energy budget are presented and discussed in detail in the present work.
Lessons in solid-state kinetics from nuclear energy research
International Nuclear Information System (INIS)
The field of research on solid-state kinetics grew enormously, along with the rest of materials research, in the decades following World War II. The author discusses how research on kinetics in the U.S., the United Kingdom, France and the U.S.S.R. is linked to the reactor development program. This is due to material problems in reactors caused by solid-state reactions or diffusion, the availability of reactor-produced radiotracers, and the early realization of the close connections among radiation behavior, point defects and diffusion
Density dependence of the single particle kinetic energy in {sup 3}He-{sup 4}He
Energy Technology Data Exchange (ETDEWEB)
Azuah, R.T. [Keele Univ. (United Kingdom). Dept. of Physics]|[Rutherford Appleton Lab., Chilton, Didcot (United Kingdom); Stirling, W.G. [Keele Univ. (United Kingdom). Dept. of Physics; Gibbs, M.R. [Keele Univ. (United Kingdom). Dept. of Physics; Sokol, P.E. [Dept. of Physics, Pennsylvania State Univ., University Park, PA (United States); Mayers, J. [Rutherford Appleton Lab., Chilton, Didcot (United Kingdom)
1995-08-01
We present inelastic neutron scattering measurements of liquid {sup 3}He-{sup 4}He mixtures at 1.5 K and at {sup 3}He concentrations of 0,15,40,70 and 100%. There is little apparent concentration dependence of the {sup 3}He kinetic energy, in disagreement with recent variational calculations for mixtures. The kinetic energy of the {sup 4}He component for the lower concentration mixtures is consistent with theoretical predictions. (orig.).
Temporal Variability of Oceanic Eddy Kinetic Energy: A High Resolution Model Analysis
Rieck, Jan Klaus
2014-01-01
Mesoscale variability of velocities is an important part of the global ocean circulation, as it contains more kinetic energy than the mean flow over most of the ocean. Understanding its generation, dissipation and modulation processes therefore is crucial to better understand ocean circulation in general. In this thesis, a global 1/12◦ ocean model (ORCA12) is used to study the distribution of mean surface Eddy Kinetic Energy (EKE), its seasonal cycle and possible driving mechanisms, ...
International Nuclear Information System (INIS)
We propose a kinetic energy density functional scheme with nonlocal terms based on the von Weizsaecker functional, instead of the more traditional approach where the nonlocal terms have the structure of the Thomas-Fermi functional. The proposed functionals recover the exact kinetic energy and reproduce the linear response function of homogeneous electron systems. In order to assess their quality, we have tested the total kinetic energies as well as the kinetic energy density for atoms. The results show that these nonlocal functionals give as good results as the most sophisticated functionals in the literature. The proposed scheme for constructing the functionals means a step ahead in the field of fully nonlocal kinetic energy functionals, because they are capable of giving better local behavior than the semilocal functionals, yielding at the same time accurate results for total kinetic energies. Moreover, the functionals enjoy the possibility of being evaluated as a single integral in momentum space if an adequate reference density is defined, and then quasilinear scaling for the computational cost can be achieved
International Nuclear Information System (INIS)
Recently, Blyumkina et al. have noted tfte existence ot fission channel ettects in the total kinetic energy of fragments of fission induced by s- and p-wave neutrons. Effects of this nature can also be expected in the variation of the fragment kinetic energies from resonance to resonance in low-energy (s-wave) neutron-induced fission. A fission-fragment detector whose efficiency is dependent on the kinetic energy of the fragments was used in the study of the slow-neutron-induced fission of U235. Comparing the counting-rate of this detector with a conventional fission detector, whose efficiency is independent of the fragment kinetic energy, shows that there exists a variation in the kinetic energy of certain fragments with neutron energy in the neutron energy region from 0.025 to 1 eV. In order to determine the response of the kinetic-energy-sensitive detector, it was necessary to measure the rangè-energy relations of fission fragments in various media, including noble gases and metallic foils. It was estimated from these data that the variation in the fragment kinetic energy release is ∼500 keV, for those fission events that give the lightest and most energetic of the heavy fragments. The variation in fragment kinetic energy is strongly asymmetric about the 0.28-eV resonance in U235, and suggests that the fragment kinetic energy sensitively reflects the presence of interference effects among resonances in fission. A multi-level multi-channel analysis of the data has been made, based on the parameters of Vogt and under the assumption that different fission channels lead to different configurations at scission, such that the kinetic energy release is also different. Previously a major objection to multi-level multi-channel analysis in fission has been that the parameters obtained are not unique. However, the possibility of observing partial fission cross-sections (fission occurring by way of one channel only) removes one of the ambiguities inherent in the multi
Leading gradient correction to the kinetic energy for two-dimensional fermion gases
Trappe, Martin-Isbjörn; Len, Yink Loong; Ng, Hui Khoon; Müller, Cord Axel; Englert, Berthold-Georg
2016-04-01
Density-functional theory (DFT) is notorious for the absence of gradient corrections to the two-dimensional (2D) Thomas-Fermi kinetic-energy functional; it is widely accepted that the 2D analog of the 3D von Weizsäcker correction vanishes, together with all higher-order corrections. Contrary to this long-held belief, we show that the leading correction to the kinetic energy does not vanish, is unambiguous, and contributes perturbatively to the total energy. This insight emerges naturally in a simple extension of standard DFT, which has the effective potential energy as a functional variable on equal footing with the single-particle density.
Movers and Shakers: Kinetic Energy Harvesting for the Internet of Things
Gorlatova, Maria; Sarik, John; Grebla, Guy; Cong, Mina; Kymissis, Ioannis; Zussman, Gil
2013-01-01
Numerous energy harvesting wireless devices that will serve as building blocks for the Internet of Things (IoT) are currently under development. However, there is still only limited understanding of the properties of various energy sources and their impact on energy harvesting adaptive algorithms. Hence, we focus on characterizing the kinetic (motion) energy that can be harvested by a wireless node with an IoT form factor and on developing energy allocation algorithms for such nodes. In this ...
High-energy interactions in Kinetic Inductance Detectors arrays
D'Addabbo, A; Goupy, J; Benoit, A; Bourrion, O; Catalano, A; Macias-Perez, J F; Monfardini, A
2015-01-01
The impacts of Cosmic Rays on the detectors are a key problem for space-based missions. We are studying the effects of such interactions on arrays of Kinetic Inductance Detectors (KID), in order to adapt this technology for use on board of satellites. Before proposing a new technology such as the Kinetic Inductance Detectors for a space-based mission, the problem of the Cosmic Rays that hit the detectors during in-flight operation has to be studied in detail. We present here several tests carried out with KID exposed to radioactive sources, which we use to reproduce the physical interactions induced by primary Cosmic Rays, and we report the results obtained adopting different solutions in terms of substrate materials and array geometries. We conclude by outlining the main guidelines to follow for fabricating KID for space-based applications.
Incident energy dependence of the mean kinetic energy, flow and temperature azimuthal distributions
International Nuclear Information System (INIS)
The squeeze-out phenomena initially predicted by hydrodynamical calculations has been extensively studied experimentally. A unified representation of the observed trends can be done in terms of the azimuthal distribution of the total mass or kinetic energy. Previously reported comprehensive description of the squeeze-out phenomena in the range 0.25 - 1.15 A · GeV was based on the parametrization of the total mass spectra with an expression characteristic for radially symmetric shell expansion. As far as such a situation can hardly be encountered in heavy ion collisions and is not specific at all for mid-central geometries, we prefer to present also the experimental information free of any model which can be used to extract it. Due to this reasons we report also the results on azimuthal distribution of the mean kinetic energy (kincm>) besides the ones corresponding to β and T values. The azimuthal distributions of kincm>, β and T can be fit with the following expression: (kincm>, β,T) = (kincm>, β,T)0 - (Δ kincm>, Δβ, ΔT) ·cos2Φ. The excitation functions of (kincm>, β,T)max and (kincm>, β,T)min from 90 A · MeV to 400 A · MeV are given. The ellipsoidal character of the flow with the major axis perpendicular to the reaction plane constantly enhances from 90 to 400 A· MeV. At 90 A · MeV the two values are very similar. The lower slope in (E,β,T)min is due to the fact that the violence of the expansion increases faster as a function of incident energy than the decrease of the passage time. At higher incident energy the relativistic contraction and the gradient of the thermal pressure in the reaction plane due to the confinement created by the spectator matter are increasing. The two slopes reverse and a crossing point is expected. It would correspond to an elliptic flow with the major axis aligned in the reaction plane. A larger modulation in the mean kinetic energy or flow relative to temperature can be explained by the larger variation of the
Wang, Guiji; Chen, Xuemiao; Cai, Jintao; Zhang, Xuping; Chong, Tao; Luo, Binqiang; Zhao, Jianheng; Sun, Chengwei; Tan, Fuli; Liu, Cangli; Wu, Gang
2016-06-01
A high current pulsed power generator CQ-3-MMAF (Multi-Modules Assembly Facility, MMAF) was developed for material dynamics experiments under ramp wave and shock loadings at the Institute of Fluid Physics (IFP), which can deliver 3 MA peak current to a strip-line load. The rise time of the current is 470 ns (10%-90%). Different from the previous CQ-4 at IFP, the CQ-3-MMAF energy is transmitted by hundreds of co-axial high voltage cables with a low impedance of 18.6 mΩ and low loss, and then hundreds of cables are reduced and converted to tens of cables into a vacuum chamber by a cable connector, and connected with a pair of parallel metallic plates insulated by Kapton films. It is composed of 32 capacitor and switch modules in parallel. The electrical parameters in short circuit are with a capacitance of 19.2 μF, an inductance of 11.7 nH, a resistance of 4.3 mΩ, and working charging voltage of 60 kV-90 kV. It can be run safely and stable when charged from 60 kV to 90 kV. The vacuum of loading chamber can be up to 10-2 Pa, and the current waveforms can be shaped by discharging in time sequences of four groups of capacitor and switch modules. CQ-3-MMAF is an adaptive machine with lower maintenance because of its modularization design. The COMSOL Multi-physics® code is used to optimize the structure of some key components and calculate their structural inductance for designs, such as gas switches and cable connectors. Some ramp wave loading experiments were conducted to check and examine the performances of CQ-3-MMAF. Two copper flyer plates were accelerated to about 3.5 km/s in one shot when the working voltage was charged to 70 kV. The velocity histories agree very well. The dynamic experiments of some polymer bonded explosives and phase transition of tin under ramp wave loadings were also conducted. The experimental data show that CQ-3-MMAF can be used to do material dynamics experiments in high rate and low cost shots. Based on this design concept, the peak
Energy Technology Data Exchange (ETDEWEB)
Vos, M. [Atomic and Molecular Physics Laboratories, Research School of Physics and Engineering, Australian National University, Canberra ACT (Australia); Marmitt, G. G. [Atomic and Molecular Physics Laboratories, Research School of Physics and Engineering, Australian National University, Canberra ACT (Australia); Instituto de Fisica da Universidade Federal do Rio Grande do Sul, Avenida Bento Goncalves 9500, 91501-970 Porto Alegre, RS (Brazil); Finkelstein, Y. [Nuclear Research Center — Negev, Beer-Sheva 84190 (Israel); Moreh, R. [Physics Department, Ben-Gurion University of the Negev, Beer-Sheva 84105 (Israel)
2015-09-14
Reflection electron energy loss spectra from some insulating materials (CaCO{sub 3}, Li{sub 2}CO{sub 3}, and SiO{sub 2}) taken at relatively high incoming electron energies (5–40 keV) are analyzed. Here, one is bulk sensitive and a well-defined onset of inelastic excitations is observed from which one can infer the value of the band gap. An estimate of the band gap was obtained by fitting the spectra with a procedure that includes the recoil shift and recoil broadening affecting these measurements. The width of the elastic peak is directly connected to the mean kinetic energy of the atom in the material (Doppler broadening). The experimentally obtained mean kinetic energies of the O, C, Li, Ca, and Si atoms are compared with the calculated ones, and good agreement is found, especially if the effect of multiple scattering is taken into account. It is demonstrated experimentally that the onset of the inelastic excitation is also affected by Doppler broadening. Aided by this understanding, we can obtain a good fit of the elastic peak and the onset of inelastic excitations. For SiO{sub 2}, good agreement is obtained with the well-established value of the band gap (8.9 eV) only if it is assumed that the intensity near the edge scales as (E − E{sub gap}){sup 1.5}. For CaCO{sub 3}, the band gap obtained here (7 eV) is about 1 eV larger than the previous experimental value, whereas the value for Li{sub 2}CO{sub 3} (7.5 eV) is the first experimental estimate.
International Nuclear Information System (INIS)
Reflection electron energy loss spectra from some insulating materials (CaCO3, Li2CO3, and SiO2) taken at relatively high incoming electron energies (5–40 keV) are analyzed. Here, one is bulk sensitive and a well-defined onset of inelastic excitations is observed from which one can infer the value of the band gap. An estimate of the band gap was obtained by fitting the spectra with a procedure that includes the recoil shift and recoil broadening affecting these measurements. The width of the elastic peak is directly connected to the mean kinetic energy of the atom in the material (Doppler broadening). The experimentally obtained mean kinetic energies of the O, C, Li, Ca, and Si atoms are compared with the calculated ones, and good agreement is found, especially if the effect of multiple scattering is taken into account. It is demonstrated experimentally that the onset of the inelastic excitation is also affected by Doppler broadening. Aided by this understanding, we can obtain a good fit of the elastic peak and the onset of inelastic excitations. For SiO2, good agreement is obtained with the well-established value of the band gap (8.9 eV) only if it is assumed that the intensity near the edge scales as (E − Egap)1.5. For CaCO3, the band gap obtained here (7 eV) is about 1 eV larger than the previous experimental value, whereas the value for Li2CO3 (7.5 eV) is the first experimental estimate
Effect of kinetic energy on the doping efficiency of cesium cations into superfluid helium droplets
International Nuclear Information System (INIS)
We present an experimental investigation of the effect of kinetic energy on the ion doping efficiency of superfluid helium droplets using cesium cations from a thermionic emission source. The kinetic energy of Cs+ is controlled by the bias voltage of a collection grid collinearly arranged with the droplet beam. Efficient doping from ions with kinetic energies from 20 eV up to 480 V has been observed in different sized helium droplets. The relative ion doping efficiency is determined by both the kinetic energy of the ions and the average size of the droplet beam. At a fixed source temperature, the number of doped droplets increases with increasing grid voltage, while the relative ion doping efficiency decreases. This result implies that not all ions are captured upon encountering with a sufficiently large droplet, a deviation from the near unity doping efficiency for closed shell neutral molecules. We propose that this drop in ion doping efficiency with kinetic energy is related to the limited deceleration rate inside a helium droplet. When the source temperature changes from 14 K to 17 K, the relative ion doping efficiency decreases rapidly, perhaps due to the lack of viable sized droplets. The size distribution of the Cs+-doped droplet beam can be measured by deflection and by energy filtering. The observed doped droplet size is about 5 × 106 helium atoms when the source temperature is between 14 K and 17 K
Institute of Scientific and Technical Information of China (English)
ZUO Qunjie; GAO Shouting; L(U) Daren
2012-01-01
The local features of transient kinetic energy and available potential energy were investigated using ECMWF (European Centre for Medium-Range Weather Forecasts) Interim Reanalysis data for the stratospheric sudden warming (SSW) event of January 2009.The Western Europe high plays important roles in the propagation of the energy from North America to Eurasian.When the Western Europe high appeared and shifted eastward,energy conversions increased and energy propagated from North America to Eurasian as a form of interaction energy flow.The baroclinic conversion between transient-eddy kinetic energy (Ke)and transient-eddy available potential energy (Ae) and the horizontal advection of geopotential height were approximately one order of magnitude less than Ke and Ae generation terms.So,these terms were less important to this SSW event.
Energy Technology Data Exchange (ETDEWEB)
Avila, Ivonete; Silva, Eugenio A.G.; Mortari, Daniela A.; Crnkovic, Paula M.; Milioli, Fernando E. [University of Sao Paulo (EESC/USP), Sao Carlos, SP (Brazil). Engineering School. Group of Thermal and Fluids Engineering], Emails: iavila@sc.usp.br, eugenio.silva@usp.br, paulam@sc.usp.br, milioli@sc.usp.br
2010-07-01
This paper evaluates the behavior of kinetic energy for different heating rates ({alpha}) and particle sizes of the material in the study of the coal combustion process. It aims to obtain a response surface in a large range of particle size, using heating rates between the minimum and maximum values allowed by the equipment. Therefore it searches for a model to evaluate the interaction effect between particle size and the heating rate and to predict the activation energy of the process studied. The activation energy of the process was determined using the isoconversional model Model Free Kinetics. In this model, the activation energy (E{sub {alpha}}) is obtained as a function of the reaction extent ({alpha}). The subscript in E{sub {alpha}} designates the values related to a given value of conversion ({alpha}). All experiments were conducted in thermogravimetric balance using samples of a Brazilian coal (EC4500) witch average particle size between 163 to 650 {mu}m and heating rates between 10 and 40 deg C min{sup -1} in dynamic atmosphere of air. A central rotatable composite design was applied for the 2{sup 2} factorial design including 4 tests under the axial conditions and 3 repetitions in the central point. As expected, the results show that both the particle size and the heating rate affected significantly the values of activation energy of the coal combustion process obtained by the model used. (author)
Vibrational energy-transfer kinetics in molecular disequilibrium. Progress report
International Nuclear Information System (INIS)
A continuous wave CO laser was used to excite the vibrational mode of CO in gas mixtures. 13C isotope enrichment was studied. High steady-state excitation of the CO vibrational mode (0.3 eV/molecule) was achieved, while a translational-rotational temperature near 3000K was maintained by the steady flow of cold gas into the cell. Kinetics of the observed C2 formation were studied. Diagnostic experiments were begun to detect reaction intermediates in the enrichment process
Experimental free energy measurements of kinetic molecular states using fluctuation theorems
Alemany, Anna; Junier, Ivan; Ritort, Felix; 10.1038/nphys2375
2013-01-01
Recent advances in non-equilibrium statistical mechanics and single molecule technologies make it possible to extract free energy differences from irreversible work measurements in pulling experiments. To date, free energy recovery has been focused on native or equilibrium molecular states, whereas free energy measurements of kinetic states (i.e. finite lifetime states that are generated dynamically and are metastable) have remained unexplored. Kinetic states can play an important role in various domains of physics, such as nanotechnology or condensed matter physics. In biophysics, there are many examples where they determine the fate of molecular reactions: protein and peptide-nucleic acid binding, specific cation binding, antigen-antibody interactions, transient states in enzymatic reactions or the formation of transient intermediates and non-native structures in molecular folders. Here we demonstrate that it is possible to obtain free energies of kinetic states by applying extended fluctuation relations. T...
Logarithmic entropy--corrected holographic dark energy with non--minimal kinetic coupling
Amani, Ali R; Farajollahi, H; Pourali, M
2011-01-01
In this paper, we have considered a cosmological model with the non--minimal kinetic coupling terms and investigated its cosmological implications with respect to the logarithmic entropy-- corrected holographic dark energy (LECHDE). The correspondence between LECHDE in flat FRW cosmology and the phantom dark energy model with the aim to interpret the current universe acceleration is also examined.
International Nuclear Information System (INIS)
The k0-IAEA software was used to determine full peak energy efficiency of a High Purity Germanium (HPGe) co-axial detector within the energy range of 121.8 - 2204.5keV and geometries of l7cm, 15cm and 2cm. The experimentally (direct technique) determination of the efficiency of the co-axial detector was within the energy range of 59.54 - 2204.5keV. Plotted ratios of the k0-IAEA derived efficiency over the k0-fitted FEPE values showed slight oscillations at certain energies attributed to the characteristics of the detector while the results of the ratio of k0-IAEA FEPE measurement over the experimentally derived efficiency obtained yielded inconsequential oscillations at certain energy around the unity mark. These deviations of 0.1 to 6% for the three geometries measured from the k0-IAEA experimental data agreed to the accurate and large acceptance of the software for analysis.
International Nuclear Information System (INIS)
A straightforward derivation of relativistic expressions for the mechanical momentum, kinetic and total energies, and mass-energy equivalence (including potential energy) which does not require any knowledge of the energy-momentum relation for electromagnetic waves or consideration of elastic collisions, but is directly based on Newton's second law and Lorentz's transformations, is presented in this paper. The existence of an invariant force is shown to be important for the validity of the relativistic mechanics
Maligaspe, Eranda; Kumpulainen, Tatu; Lemmetyinen, Helge; Tkachenko, Nikolai V; Subbaiyan, Navaneetha K; Zandler, Melvin E; D'Souza, Francis
2010-01-14
Singlet-singlet energy transfer in self-assembled via axial coordination of imidazole-appended (at different positions of one of the meso-phenyl entities) free-base tetraphenylporphyrin, H(2)PIm, to either zinc phthalocyanine, ZnPc, or zinc naphthalocyanine, ZnNc, dyads is investigated in noncoordinating solvents, o-dichlorobenzene and toluene, using both steady-state and time-resolved transient absorption techniques. The newly formed supramolecular dyads were fully characterized by spectroscopic, computational, and electrochemical methods. The binding constants measured from optical absorption spectral data were found to be in the range of 10(4)-10(5) M(-1) for the 1:1 dyads, suggesting fairly stable complex formation. Electrochemical and computational studies suggested that photoinduced electron transfer is a thermodynamically unfavorable process when free-base porphyrin is excited in these dyads. Selective excitation of the donor free-base porphyrin entity was possible in both types of dyads formed by either of the ZnPc or ZnNc energy acceptors. Efficient singlet-singlet energy transfer was observed in these dyads, and the position of imidazole linkage on the free-base porphyrin entity, although flexible, seems to have some control over the overall efficiency of excited energy transfer process. Kinetics of energy transfer was monitored by performing transient absorption measurements using both up-conversion and pump-probe techniques. Such studies revealed ultrafast singlet-singlet energy transfer in the studied dyads with time constants on the order of 2-25 ps depending upon the type of the dyad. PMID:19928821
Mean kinetic energy budget of wakes within an array of model wind turbines and porous discs
Cal, Raúl Bayoán; Camp, Elizabeth
2015-11-01
Wind turbines are often modeled as porous actuator discs within computational studies. In this wind tunnel study, stereo particle image velocimetry (SPIV) is used to characterize the wakes within a 4 ×3 model wind turbine array and an analogous array of porous disks. The SPIV measurements are performed upstream between - 2 . 9 <= x / D <= - 0 . 3 and downstream between 0 . 7 <= x / D <= 5 . 6 of the center turbine in the fourth row. To provide context, the similarities and differences in the flow fields as well as the mean and turbulent stresses are found. The primary analysis revolves around the mean kinetic energy budget in the wakes for both cases, model turbines and discs, obtained by the computation of mean kinetic energy, production of turbulence and flux of kinetic energy as these are equivalent to a measure of extracted power.
Dynamic force spectroscopy of DNA hairpins: I. Force kinetics and free energy landscapes
International Nuclear Information System (INIS)
We investigate the thermodynamics and kinetics of DNA hairpins that fold/unfold under the action of applied mechanical force. We introduce the concept of the molecular free energy landscape and derive simplified expressions for the force dependent Kramers–Bell rates. To test the theory we have designed a specific DNA hairpin sequence that shows two-state cooperative folding under mechanical tension and carried out pulling experiments using optical tweezers. We show how we can determine the parameters that characterize the molecular free energy landscape of such sequences from rupture force kinetic studies. Finally we combine such kinetic studies with experimental investigations of the Crooks fluctuation relation to derive the free energy of formation of the hairpin at zero force
System Perspectives on Hydro-Kinetic Energy Conversion
Yuen, Katarina
2012-01-01
Free-flowing water currents such as tides and unregulated water courses could contribute to world electricity production given the emergence of robust technical solutions for extracting the energy. At Uppsala University, a concept for converting the energy in water currents to electricity using a vertical axis turbine with fixed blade-pitch and a direct-drive permanent magnet generator is studied. Technological equipment for extracting energy from water currents can be studied at desktop to s...
Lee, Kurnchul; Venugopal, Vishnu; Girimaji, Sharath S.
2016-08-01
Return-to-isotropy and kinetic-potential energy equipartition are two fundamental pressure-moderated energy redistributive processes in anisotropic compressible turbulence. Pressure-strain correlation tensor redistributes energy among various Reynolds stress components and pressure-dilatation is responsible for energy reallocation between dilatational kinetic and potential energies. The competition and interplay between these pressure-based processes are investigated in this study. Direct numerical simulations (DNS) of low turbulent Mach number dilatational turbulence are performed employing the hybrid thermal Lattice Boltzman method (HTLBM). It is found that a tendency towards equipartition precedes proclivity for isotropization. An evolution towards equipartition has a collateral but critical effect on return-to-isotropy. The preferential transfer of energy from strong (rather than weak) Reynolds stress components to potential energy accelerates the isotropization of dilatational fluctuations. Understanding of these pressure-based redistributive processes is critical for developing insight into the character of compressible turbulence.
Drop size distributions and kinetic energy rates in variable intensity rainfall
Assouline, Shmuel
2016-04-01
Temporal variability in rainfall intensity reflects on the drop size distribution (DSD), and affects the rainfall kinetic energy during the event. Smith et al. (2009) reported on 1-min interval rainfall intensity and corresponding DSD variability during a storm on the 22/7/06 at Princeton, NJ. They reported also on DSDs characteristics of heavy convective rainfall events during the whole summer. Applying the DSD model of Assouline and Mualem (1997), it is shown that: (a) a similar relationship between the mean drop size and the rainfall intensity characterized the local rainfall at both the seasonal and the single storm scale; (b) using the mean drop size as a scaling factor of the DSD removes the rainfall intensity dependence at the intrastorm scale, providing a powerful tool to deal with temporal variability of rainfall rates during rainfall events. For a storm characterized by a given temporal variability of intensities, three different ways of evaluating kinetic energy per unit mass or time were applied. By comparison to estimates accounting for rainfall temporal variability and related full DSDs, representing the storm by mean intensity and drop diameter tends to overestimate kinetic energy for low intensities and underestimate it for the higher ones. The relative error for the kinetic energy per unit of mass is ±45% and shifts from negative to positive sign for I>25 mm/h. For the kinetic energy per unit of time, the relative error ranges from -100% to +210% and changes sign for I>45 mm/h. When temporal variation of intensity is accounted for but drops are characterized by their mean values instead of the full DSD, kinetic energy is underestimated by 20% on average. Consequently, accounting for temporal variability in rainfall intensity during a storm has a notable impact on the erosive power of the rainfall.
Neutrons and Kinetic Energy of Fragments in Fission of Heavy Nuclei
International Nuclear Information System (INIS)
The distribution of excitation energy and kinetic energy depending on the mass of the fragment formed in heavy- isotope fission by thermal neutrons is experimentally investigated. The excitation energy is shown to have a low minimum in the region of the double-magic fragment (M ∼132), to increase in the symmetrical fission area and to be at its maximum for fragments complementary to magic. The kinetic energy of the fragments measured for U235 correlates with the excitation energy. The total energy release according to the experimental data is in good agreement with calculations according to Milton's mass tables in every case except that of strongly asymmetric fission. In the measurements conducted, the ratio of the maximum of the fragment yield curve to the minimum (after neutron escape) was 500 : 1. (author)
Exact kinetic energy enables accurate evaluation of weak interactions by the FDE-vdW method
International Nuclear Information System (INIS)
The correlation energy of interaction is an elusive and sought-after interaction between molecular systems. By partitioning the response function of the system into subsystem contributions, the Frozen Density Embedding (FDE)-vdW method provides a computationally amenable nonlocal correlation functional based on the adiabatic connection fluctuation dissipation theorem applied to subsystem density functional theory. In reproducing potential energy surfaces of weakly interacting dimers, we show that FDE-vdW, either employing semilocal or exact nonadditive kinetic energy functionals, is in quantitative agreement with high-accuracy coupled cluster calculations (overall mean unsigned error of 0.5 kcal/mol). When employing the exact kinetic energy (which we term the Kohn-Sham (KS)-vdW method), the binding energies are generally closer to the benchmark, and the energy surfaces are also smoother
Vafaee, Mohsen
2007-01-01
The electronic full dimensional of the time dependent Schr\\"odinger equation of the aligned deuterium molecular ion numerically is solved for the simulation of the complicated dissociative ionization process and compared with the related experimental results. In this work, the R-dependent ionization rate and the enhanced ionization phenomenon beyond the Born-Oppenheimer approximation are introduced and calculated and enhanced ionization is directly related to kinetic energy release (KER) of nuclear energy. The signification of the Coulomb explosion energy and dissociation-ionization energy in the ionization channel are comparatively revealed in the total kinetic energy release. It shows that the dissociation-ionization energy spectra in the ionization channel have significant role in the structure of the KER spectrum.
Kinetics of energy transfer processes in C-phycocyanin complexes
Institute of Scientific and Technical Information of China (English)
赵井泉; 李晔
1999-01-01
The antenna system of algae for photosynthesis is a functional entity composed of various phycobiliproteins and the linker polypeptides. Up to now, high-resolution crystal structure data have been available only for the isolated phycobiliproteins. To have an understanding of the functional connection between different phycobiliproteins, it is necessary to study the complexes composed of different phycobiliproteins. The energy transfer processes in C-phycocyanin complexes were studied through computer simulation because it is difficult to be studied by conventional experimental methods. The main pathways of energy flow and the dynamic property of the energy transfer were obtained. A fast transfer process between two neighboring disks was observed through analyzing the distribution curves of excitation energy over time. According to the definition of the time constants for energy transfer in time-resolved spectrum techniques, for a complex with three C-phycoeyanin hexamer disks, a fluorescence-rising comp
Theoretical study of atoms by the electronic kinetic energy density and stress tensor density
Nozaki, Hiroo; Tachibana, Akitomo
2016-01-01
We analyze the electronic structure of atoms in the first, second and third periods using the electronic kinetic energy density and stress tensor density, which are local quantities motivated by quantum field theoretic consideration, specifically the rigged quantum electrodynamics. We compute the zero surfaces of the electronic kinetic energy density, which we call the electronic interfaces, of the atoms. We find that their sizes exhibit clear periodicity and are comparable to the conventional atomic and ionic radii. We also compute the electronic stress tensor density and its divergence, tension density, of the atoms, and discuss how their electronic structures are characterized by them.
A multiscale numerical study into the cascade of kinetic energy leading to severe local storms
Paine, D. A.; Kaplan, M. L.
1977-01-01
The cascade of kinetic energy from macro- through mesoscales is studied on the basis of a nested grid system used to solve a set of nonlinear differential equations. The kinetic energy cascade and the concentration of vorticity through the hydrodynamic spectrum provide a means for predicting the location and intensity of severe weather from large-scale data sets. A mechanism described by the surface pressure tendency equation proves to be important in explaining how initial middle-tropospheric mass-momentum imbalances alter the low-level pressure field.
A Kinetic Study of Marginal Soil Energy Plant Helianthus annuus Stalk Pyrolysis
Huaxiao Yan; Hui Zhao; Yan Zhang; Yuanyu Tian; Kechang Xie
2013-01-01
The pyrolytic characteristics and kinetics of new marginal soil energy plant Helianthus annuus stalk were investigated using thermogravimetric (TG) method from 50 to 800°C in an inert argon atmosphere at different heating rates of 5, 10, 20, and 30°C min−1. The kinetic parameters of activation energy and pre-exponential factor were deduced by Popescu, Flynn-Wall-Ozawa (FWO), and Kissinger-Akahira-Sunose (KAS) methods, respectively. The results showed that three stages appeared in the thermal ...
Nozaki, Hiroo; Ichikawa, Kazuhide; Watanabe, Taku; Aihara, Yuichi; Tachibana, Akitomo
2016-01-01
We analyze the electronic structure of lithium ionic conductors, ${\\rm Li_3PO_4}$ and ${\\rm Li_3PS_4}$, using the electronic stress tensor density and kinetic energy density with special focus on the ionic bonds among them. We find that, as long as we examine the pattern of the eigenvalues of the electronic stress tensor density, we cannot distinguish between the ionic bonds and bonds among metalloid atoms. We then show that they can be distinguished by looking at the morphology of the electronic interface, the zero surface of the electronic kinetic energy density.
Yao, Kun
2015-01-01
We demonstrate a convolutional neural network trained to reproduce the Kohn-Sham kinetic energy of hydrocarbons from electron density. The output of the network is used as a non-local correction to the conventional local and semi-local kinetic functionals. We show that this approximation qualitatively reproduces Kohn-Sham potential energy surfaces when used with conventional exchange correlation functionals. Numerical noise inherited from the non-linearity of the neural network is identified as the major challenge for the model. Finally we examine the features in the density learned by the neural network to anticipate the prospects of generalizing these models.
Fission-fragment kinetic-energy distributions from a two-dimensional Fokker-Planck equation
International Nuclear Information System (INIS)
We calculate the fission-fragment kinetic-energy distribution for the compound nucleus 213At by simultaneously taking into account spreading in a stretching degree of freedom and fluctuations in a fission degree of freedom. This is done in terms of an approximate solution of a two-dimensional Fokker-Planck equation obtained by propagating Gaussian bundles in momentum space. When compared as functions of nuclear temperature with experimental data, our calculated mean kinetic energies are in approximate agreement and our calculated variances are slightly too small
The distribution of eddy kinetic and potential energies in the global ocean
Ferrari, Raffaele; Wunsch, Carl
2009-01-01
Understanding of the major sources, sinks, and reservoirs of energy in the ocean is briefly updated in a diagram. The nature of the dominant kinetic energy reservoir, that of the balanced variablity, is then found to be indistinguishable in the observations from a sum of barotropic and first baroclinic ordinary quasi-geostrophic modes. Little supporting evidence is available to partition the spectra among forced motions and turbulent cascades, along with significant energy more consistent wit...
Properties of the total kinetic energy balance in wall-bounded turbulent flows
Zhou, Ang; Klewicki, Joseph
2015-11-01
The properties of the total kinetic energy balance in turbulent boundary layer and channel flows are explored empirically. The total kinetic energy transport equation, which is the combination of mean and turbulent kinetic energy transport equations, is appropriately simplified for fully developed turbulent channel flow and the two-dimensional flat plate boundary layer. Different from the turbulence kinetic energy equation, a suitable grouping of terms is found that cleanly segregates the leading balances in the total energy equation. Available high-quality data reveal a four-layer structure for the energetics that is qualitatively different from the four-layer description of the mean dynamics [Wei et al. 2005, J. Fluid Mech. 522, 303]. The wall-normal widths of the layers exhibit significant Reynolds number dependencies, and these are empirically quantified. Present findings indicate that each of the four layers is characterized by a predominance of some of the terms in the governing equations. Particular significance is attached to the ratio of the sum of viscous diffusion and dissipation terms to the production/turbulent diffusion term, since these groupings allow the characterization of the layer widths. The third layer exhibits a complex leading order balance exchange that is described in detail.
Influence of the Richtmyer-Meshkov instability on the kinetic energy spectrum.
Energy Technology Data Exchange (ETDEWEB)
Weber, Christopher R. (University of Wisconsin-Madison, Madison, WI)
2010-09-01
The fluctuating kinetic energy spectrum in the region near the Richtmyer-Meshkov instability (RMI) is experimentally investigated using particle image velocimetry (PIV). The velocity field is measured at a high spatial resolution in the light gas to observe the effects of turbulence production and dissipation. It is found that the RMI acts as a source of turbulence production near the unstable interface, where energy is transferred from the scales of the perturbation to smaller scales until dissipation. The interface also has an effect on the kinetic energy spectrum farther away by means of the distorted reflected shock wave. The energy spectrum far from the interface initially has a higher energy content than that of similar experiments with a flat interface. These differences are quick to disappear as dissipation dominates the flow far from the interface.
International Nuclear Information System (INIS)
The present work is devoted to the fragments produced in the neutrons induced fission of 235U, performed with the time of flight-energy spectrometer 'Cosi Fan Tutte' recently built at the neutron high flux reactor of the Laue-Langevin Institute at Grenoble. Mass-kinetic energy-nuclear charge correlations were measured for the light fission fragment group. Nuclear charges were identified for the first time on this spectrometer using the range difference of the fission fragments in an axial field ionisation chamber. The present results are in good agreement with the previous one obtained using the spectrometer 'Lohengrin', which proves the validity of the methods which we developed. In addition, we extend the measurements to higher kinetic energies. The structures which appear in the distributions are attributed to spherical and deformed shell effects in the nascent fragments and to even odd effects. The study of thermal neutron induced fission of 229Th, which is scarcely known, has been started. (author)
Sorgente, R.; A. Olita; P. Oddo; L. Fazioli; A. Ribotti
2011-01-01
The spatial and temporal variability of eddy and mean kinetic energy of the Central Mediterranean region has been investigated, from January 2008 to December 2010, by mean of a numerical simulation mainly to quantify the mesoscale dynamics and their relationships with physical forcing. In order to understand the energy redistribution processes, the baroclinic energy conversion has been analysed, suggesting hypotheses about the drivers of the mesoscale activity in this area. The ocean model us...
Simulations of thermodynamics and kinetics on rough energy landscapes with milestoning.
Bello-Rivas, Juan M; Elber, Ron
2016-03-01
We investigated by computational means the kinetics and stationary behavior of stochastic dynamics on an ensemble of rough two-dimensional energy landscapes. There are no obvious separations of temporal scales in these systems, which constitute a simple model for the behavior of glasses and some biomaterials. Even though there are significant computational challenges present in these systems due to the large number of metastable states, the Milestoning method is able to compute their kinetic and thermodynamic properties exactly. We observe two clearly distinguished regimes in the overall kinetics: one in which diffusive behavior dominates and another that follows an Arrhenius law (despite the absence of a dominant barrier). We compare our results with those obtained with an exactly-solvable one-dimensional model, and with the results from the rough one-dimensional energy model introduced by Zwanzig. © 2015 Wiley Periodicals, Inc. PMID:26265358
The impact of rotor labyrinth seal leakage flow on the loss generation in an axial turbine
Energy Technology Data Exchange (ETDEWEB)
Anker, J.; Mayer, J.; Casey, M. [Stuttgart Univ. (Germany). Institute for Thermal Turbomachinery and Machinery Lab.
2005-09-15
This paper examines the impact of labyrinth seal leakage flow over the rotor shroud on the loss generation in an axial turbine stage. Numerical studies have been carried out with an in-house solver using the Baldwin-Lomax turbulence model to identify the changes in secondary flow structures. The code has been validated for this application using test data from a low-speed axial turbine stage with a simple generic rotor shroud labyrinth seal. Numerical simulations are carried out with different clearance gaps (0, 1, and 3 mm) and without cavity wells. The simulations are used to distinguish the separate interactions of the main flow with the leakage flow and the cavity flow. The leakage flow causes a strong increase in the secondary flow kinetic energy in the downstream stator. Both the leakage flow and the cavity flow lead to an increase in the secondary kinetic energy in the rotor. (author)
International Nuclear Information System (INIS)
Implantable medical devices usually require a battery to operate and this can represent a severe restriction. In most cases, the implantable medical devices must be surgically replaced because of the dead batteries; therefore, the longevity of the whole implantable medical device is determined by the battery lifespan. For this reason, researchers have been studying energy harvesting techniques from the human body in order to obtain batteryless implantable medical devices. The human body is a rich source of energy and this energy can be harvested from body heat, breathing, arm motion, leg motion or the motion of other body parts produced during walking or any other activity. In particular, the main human-body energy sources are kinetic energy and thermal energy. This paper reviews the state-of-art in kinetic and thermoelectric energy harvesters for powering implantable medical devices. Kinetic energy harvesters are based on electromagnetic, electrostatic and piezoelectric conversion. The different energy harvesters are analyzed highlighting their sizes, energy or power they produce and their relative applications. As they must be implanted, energy harvesting devices must be limited in size, typically about 1 cm3. The available energy depends on human-body positions; therefore, some positions are more advantageous than others. For example, favorable positions for piezoelectric harvesters are hip, knee and ankle where forces are significant. The energy harvesters here reported produce a power between 6 nW and 7.2 mW; these values are comparable with the supply requirements of the most common implantable medical devices; this demonstrates that energy harvesting techniques is a valid solution to design batteryless implantable medical devices. (topical review)
Axial structure of the nucleon
Energy Technology Data Exchange (ETDEWEB)
Veronique Bernard; Latifa Elouadrhiri; Ulf-G Meissner
2002-01-01
We review the current status of experimental and theoretical understanding of the axial nucleon structure at low and moderate energies. Topics considered include (quasi)elastic (anti)neutrino-nucleon scattering, charged pion electroproduction off nucleons and ordinary as well as radiative muon capture on the proton.
A Kinetic Study of Marginal Soil Energy Plant Helianthus annuus Stalk Pyrolysis
Directory of Open Access Journals (Sweden)
Huaxiao Yan
2013-01-01
Full Text Available The pyrolytic characteristics and kinetics of new marginal soil energy plant Helianthus annuus stalk were investigated using thermogravimetric (TG method from 50 to 800°C in an inert argon atmosphere at different heating rates of 5, 10, 20, and 30°C min−1. The kinetic parameters of activation energy and pre-exponential factor were deduced by Popescu, Flynn-Wall-Ozawa (FWO, and Kissinger-Akahira-Sunose (KAS methods, respectively. The results showed that three stages appeared in the thermal degradation process. The primary devolatilization stage of H. annuus stalk can be described by the Avrami-Erofeev function (n=4. The average activation energy of H. annuus stalk was only 142.9 kJ mol−1. There were minor kinetic compensation effects between the pre-exponential factor and the activation energy. The results suggest that H. annuus stalk is suitable for pyrolysis, and more importantly, the experimental results and kinetic parameters provided useful information for the design of pyrolytic processing system using H. annuus stalk as feedstock.
Endo, Kazunaka
2016-02-01
In the Auger electron spectra (AES) simulations, we define theoretical modified kinetic energies of AES in the density functional theory (DFT) calculations. The modified kinetic energies correspond to two final-state holes at the ground state and at the transition-state in DFT calculations, respectively. This method is applied to simulate Auger electron spectra (AES) of 2nd periodic atom (Li, Be, B, C, N, O, F)-involving substances (LiF, beryllium, boron, graphite, GaN, SiO2, PTFE) by deMon DFT calculations using the model molecules of the unit cell. Experimental KVV (valence band electrons can fill K-shell core holes or be emitted during KVV-type transitions) AES of the (Li, O) atoms in the substances agree considerably well with simulation of AES obtained with the maximum kinetic energies of the atoms, while, for AES of LiF, and PTFE substance, the experimental F KVV AES is almost in accordance with the spectra from the transitionstate kinetic energy calculations.
Kinetic, potential and surface tension energies of solitary waves in deep water
Hur, Vera Mikyoung
2015-01-01
We present an exact relation among the kinetic, potential and surface tension energies of a solitary wave in deep water in all dimensions. We deduce its non-existence in the absence of the effects of surface tension, provided that gravity acts in a direction opposite to what is physically realistic.
Kinetic, potential and surface tension energies of solitary waves in deep water
International Nuclear Information System (INIS)
We present an exact relation among the kinetic, potential and surface tension energies of a solitary wave in deep water in all dimensions. We deduce its non-existence in the absence of the effects of surface tension, provided that gravity acts in a direction opposite to what is physically realistic. (fast track communication)
Yafaev, D. R.
2010-01-01
We obtain two-sided bounds on kinetic and potential energies of a bound state of a quantum particle in the semiclassical limit, as the Planck constant $\\hbar\\ri 0$. Proofs of these results rely on the generalized virial theorem obtained in the paper as well as on a decay of eigenfunctions in the classically forbidden region.
Employing Magnetic Levitation to Monitor Reaction Kinetics and Measure Activation Energy
Benz, Lauren; Cesafsky, Karen E.; Le, Tran; Park, Aileen; Malicky, David
2012-01-01
This article describes a simple and inexpensive undergraduate-level kinetics experiment that uses magnetic levitation to monitor the progress and determine the activation energy of a condensation reaction on a polymeric solid support. The method employs a cuvette filled with a paramagnetic solution positioned between two strong magnets. The…
International Nuclear Information System (INIS)
The measurement of ion kinetic energies is important for understanding processes that occur in discharges, e.g., the influence of ions on the etching of semiconductor materials in plasma reactors. Direct measurements of ion kinetic energies striking surfaces exposed to the discharge requires sampling through an orifice in a surface. Difficulties with ion sampling through a small aperture, manifested by errors or distortions in measured ion kinetic-energy distributions (IEDs) have been encountered in previous investigations of both dc and radio-frequency (rf) discharges. The errors are usually most significant at relatively low ion energies. Previous measurements in our laboratory of IEDs for ions sampled through a 0.1-mm hole in a grounded, aluminum electrode for rf discharges in argon showed evidence of reduced detection efficiency (discrimination) for low energy ions (<10 eV), and apparent shifts in the measured ion energies for plasmas generated in other gases. It has been suggested that surface charging at or near the sampling orifice can cause both discrimination and energy shifts. The existence of an insulating, or partially insulating, layer of aluminum oxide on the surface of an electrode allows the possibility of surface-charge accumulation. In the present work, IEDs were measured at both aluminum and 304 stainless-steel grounded electrodes with 0.1 mm sampling orifices in rf plasmas generated in argon and oxygen
Directory of Open Access Journals (Sweden)
R. Sorgente
2011-05-01
Full Text Available The spatial and temporal variability of eddy and mean kinetic energy of the Central Mediterranean Sea has been investigated, from January 2008 to December 2010, by mean of a numerical simulation mainly to quantify the mesoscale dynamics and their relationships with physical forcing. In order to understand the energy redistribution processes, the baroclinic energy conversion has been analysed, suggesting hypotheses about the drivers of the mesoscale activity in this area. The ocean model used is based on the Princeton Ocean Model implemented at 1/32° horizontal resolution. Surface momentum and buoyancy fluxes are interactively computed by mean of standard bulk formulae using predicted model Sea Surface Temperature and atmospheric variables provided by the European Centre for Medium Range Weather Forecast operational analyses. At its lateral boundaries the model is one-way nested within the Mediterranean Forecasting System operational products.
The model domain has been subdivided in four sub-regions: Sardinia channel and southern Tyrrhenian Sea, Sicily channel, eastern Tunisian shelf and Libyan Sea. Temporal evolution of eddy and mean kinetic energy has been analysed, on each of the four sub-regions composing the model domain, showing different behaviours. On annual scales and within the first 5 m depth, the eddy kinetic energy represents approximately the 60 % of the total kinetic energy over the whole domain, confirming the strong mesoscale nature of the surface current flows in this area. The analyses show that the model well reproduces the path and the temporal behaviour of the main known sub-basin circulation features. New mesoscale structures have been also identified, from numerical results and direct observations, for the first time as the Pantelleria Vortex and the Medina Gyre.
The classical the kinetic energy decomposition (eddy and mean allowed to depict and to quantify the stable and fluctuating parts of the
Directory of Open Access Journals (Sweden)
R. Sorgente
2011-08-01
Full Text Available The spatial and temporal variability of eddy and mean kinetic energy of the Central Mediterranean region has been investigated, from January 2008 to December 2010, by mean of a numerical simulation mainly to quantify the mesoscale dynamics and their relationships with physical forcing. In order to understand the energy redistribution processes, the baroclinic energy conversion has been analysed, suggesting hypotheses about the drivers of the mesoscale activity in this area. The ocean model used is based on the Princeton Ocean Model implemented at 1/32° horizontal resolution. Surface momentum and buoyancy fluxes are interactively computed by mean of standard bulk formulae using predicted model Sea Surface Temperature and atmospheric variables provided by the European Centre for Medium Range Weather Forecast operational analyses. At its lateral boundaries the model is one-way nested within the Mediterranean Forecasting System operational products.
The model domain has been subdivided in four sub-regions: Sardinia channel and southern Tyrrhenian Sea, Sicily channel, eastern Tunisian shelf and Libyan Sea. Temporal evolution of eddy and mean kinetic energy has been analysed, on each of the four sub-regions, showing different behaviours. On annual scales and within the first 5 m depth, the eddy kinetic energy represents approximately the 60 % of the total kinetic energy over the whole domain, confirming the strong mesoscale nature of the surface current flows in this area. The analyses show that the model well reproduces the path and the temporal behaviour of the main known sub-basin circulation features. New mesoscale structures have been also identified, from numerical results and direct observations, for the first time as the Pantelleria Vortex and the Medina Gyre.
The classical kinetic energy decomposition (eddy and mean allowed to depict and to quantify the permanent and fluctuating parts of the circulation in the region, and
Kinetic-energy matrix elements for atomic Hylleraas-CI wave functions.
Harris, Frank E
2016-05-28
Hylleraas-CI is a superposition-of-configurations method in which each configuration is constructed from a Slater-type orbital (STO) product to which is appended (linearly) at most one interelectron distance rij. Computations of the kinetic energy for atoms by this method have been difficult due to the lack of formulas expressing these matrix elements for general angular momentum in terms of overlap and potential-energy integrals. It is shown here that a strategic application of angular-momentum theory, including the use of vector spherical harmonics, enables the reduction of all atomic kinetic-energy integrals to overlap and potential-energy matrix elements. The new formulas are validated by showing that they yield correct results for a large number of integrals published by other investigators. PMID:27250282
Shibuya, Kengo; Kawamura, Yoshihiro; Saito, Haruo
2015-06-01
Positronium(Ps) can undergo ortho-para spin conversion reaction during Ps-Xecollisions due to spin-orbit interaction. We have investigated energy dependence of this reaction rate and found it is nearly proportional to T2.1, where T is the temperature (300-623 K), while the pick-off annihilation rate is proportional to T. The strong temperature dependence of the former annihilation rate is attributed to a nature of p-wave scattering because this reaction is forbidden in s-wave scattering. In addition, a new method for measuring Ps kinetic energy has been developed with a high resolution and a high sensitivity by utilizing the strong temperature dependence as a "thermometer." Analyzingthe obtained time evolution of Ps kinetic energy, we have determined the momentum transfer cross section during Ps-Xecollisions at a very low energy (40-60 meV) to be 12(2)×10-16 cm2.
Energy conserving continuum algorithms for kinetic & gyrokinetic simulations of plasmas
Hakim, A.; Hammett, G. W.; Shi, E.; Stoltzfus-Dueck, T.
2015-11-01
We present high-order, energy conserving, continuum algorithms for the solution of gyrokinetic equations for use in edge turbulence simulations. The distribution function is evolved with a discontinuous Galerkin scheme, while the fields are evolved with a continuous finite-element method. These algorithms work for a general, possibly non-canonical, Poisson bracket operator and conserve energy exactly. Benchmark simulations with ETG turbulence in 3X/2V are shown, as well as initial applications of the algorithms to turbulence in a simplified SOL geometry. Sheath boundary conditions with recycling and secondary electron emission are implemented, and a Lenard-Bernstein collision operator is included. Extension of these algorithms to full Vlasov-Maxwell equations are presented. It is shown that with a particular choice of numerical fluxes the total (particle+field) energy is conserved. Algorithms are implemented in a flexible and open-source framework, Gkeyll, which also includes fluid models, allowing potential hybrid simulations of various plasma problems. Supported by the Max-Planck/Princeton Center for Plasma Physics, and DOE Contract DE-AC02-09CH11466.
Institute of Scientific and Technical Information of China (English)
陈光巨; 李玉学
1999-01-01
The concrete molecule-fixed （MF） kinetic energy operator for penta-atomic molecules is expressed in terms of the parameterδ, the matrix element G?, and angular momentum operator （?）. The applications of the operator are also discussed. Finally, a general compact form of kinetic energy operator suitable for calculating the rovibrational spectra of polyatomie molecules is presented.
Goutte, H.; Berger, J.F.; Casoli, P.; Gogny, D.
2005-01-01
The collective dynamics of low energy fission in 238U is described within a time-dependent formalism based on the Gaussian Overlap Approximation of the time-dependent Generator Coordinate Method. The intrinsic deformed configurations of the nucleus are determined from the self-consistent Hartree-Fock-Bogoliubov procedure employing the effective force D1S with constraints on the quadrupole and octupole moments. Fragment kinetic energy and mass distributions are calculated and compared with exp...
A multi-layer model for turbulent kinetic energy in pipe flows
Chen, Xi; Hussain, Fazle; She, Zhen-Su
2011-01-01
A multi-layer model of an energy length function is developed by employing recent results of the authors. The theory predicts the complete, mean streamwise turbulent kinetic-energy profile (MKP), in good agreement with empirical data for a wide range of Reynolds numbers (Re). In particular, a critical $Re_\\tau$ is predicted, beyond which a scaling anomaly appears and MKP develops a second peak.
On the Exchange of Kinetic and Magnetic Energy Between Clouds and the Interstellar Medium
Miniati, Francesco; Jones, T. W.; Ryu, Dongsu
1999-01-01
We investigate, through 2D MHD numerical simulations, the interaction of a uniform magnetic field oblique to a moving interstellar cloud. In particular we explore the transformation of cloud kinetic energy into magnetic energy as a result of field line stretching. Some previous simulations have emphasized the possible dynamical importance of a ``magnetic shield'' formed around clouds when the magnetic field is perpendicular to the cloud motion (Jones et al. 1996, Miniati et al. 1998). It was ...
Kinetic energy cascades in quasi-geostrophic convection in a spherical shell
International Nuclear Information System (INIS)
We consider triadic nonlinear interaction in the Navier-Stokes equation for quasi-geostrophic convection in a spherical shell. This approach helps us understand the origin of kinetic energy transport in the system and the particular scheme of mode interaction, as well as the locality of energy transfer. The peculiarity of convection in the sphere, concerned with the excitation of Rossby waves, is considered. The obtained results are compared with the results of our previous study on Cartesian geometry. (paper)
Directory of Open Access Journals (Sweden)
DEJAN MARKOVIC
2003-09-01
Full Text Available Simultaneous measurements of fluorescence and thermal emission have been performed by applying combined fluorescence and photoacoustic techniques on isolated thylakoids pretreated by prolonged illumination with saturating light. The traces were used to create Lineweaver-Burk type plots, proving clearly at least a formal analogy between the kinetics of the mechanisms governing fluorescence and thermal emission from isolated thylakoids and Michaelis-Menten kinetics of enzymatic reactions. Two characteristic parameters were calculated from them (energy storage and half-saturation light intensity in order to obtain a basic, initial response of the photosynthetic apparatus functioning under photoinhibition stress.
Joubert, D
2001-01-01
For Psi an eigenfunction of the Hamiltonian operator H = T + V, where T is the kinetic energy operator and V the potential energy operator, the following relations between expectation values are satisfied: = , ^2 = , ^2 = .
Turbulent kinetic energy spectrum in very anisothermal flows
Energy Technology Data Exchange (ETDEWEB)
Serra, Sylvain, E-mail: sylvain_serra@bbox.fr [PROcedes, Materiaux et Energie Solaire, UPR CNRS 8521, Rambla de la thermodynamique, Tecnosud, 66100 Perpignan (France); Toutant, Adrien, E-mail: adrien.toutant@univ-Perp.fr [PROcedes, Materiaux et Energie Solaire, UPR CNRS 8521, Rambla de la thermodynamique, Tecnosud, 66100 Perpignan (France); Bataille, Françoise, E-mail: francoise.bataille@promes.cnrs.fr [PROcedes, Materiaux et Energie Solaire, UPR CNRS 8521, Rambla de la thermodynamique, Tecnosud, 66100 Perpignan (France); Zhou, Ye, E-mail: yezhou@llnl.gov [Lawrence Livermore National Laboratory, Livermore, CA 94550 (United States)
2012-10-01
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.
FLYWHEEL BASED KINETIC ENERGY RECOVERY SYSTEMS (KERS INTEGRATED IN VEHICLES
Directory of Open Access Journals (Sweden)
THOMAS MATHEWS
2013-09-01
Full Text Available Today, many hybrid electric vehicles have been developed in order to reduce the consumption of fossil fuels; unfortunately these vehicles require electrochemical batteries to store energy, with high costs as well as poor conversion efficiencies. By integrating flywheel hybrid systems, these drawbacks can be overcome and can potentially replace battery powered hybrid vehicles cost effectively. The paper will explain the engineering, mechanics of the flywheel system and it’s working in detail. Each component of the flywheel-based kineticenergy recovery system will also be described. The advantages of this technology over the electric hybrids will be elucidated carefully. The latest advancements in the field, the potential future and scope of the flywheelhybrid will be assessed.
Turbulent kinetic energy spectrum in very anisothermal flows
International Nuclear Information System (INIS)
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.
Proton Kinetic Effects and Turbulent Energy Cascade Rate in the Solar Wind
Osman, Kareem T; Kiyani, Khurom H; Hnat, Bogdan; Chapman, Sandra C
2013-01-01
The first observed connection between kinetic instabilities driven by proton temperature anisotropy and estimated energy cascade rates in the turbulent solar wind is reported using measurements from the Wind spacecraft at 1 AU. We find enhanced cascade rates are concentrated along the boundaries of the ($\\beta_{\\parallel}$, $T_{\\perp}/T_{\\parallel}$)-plane, which includes regions theoretically unstable to the mirror and firehose instabilities. A strong correlation is observed between the estimated cascade rate and kinetic effects such as temperature anisotropy and plasma heating, resulting in protons 5-6 times hotter and 70-90% more anisotropic than under typical isotropic plasma conditions. These results offer new insights into kinetic processes in a turbulent regime.
Kinetic energy of throughfall in a highly diverse forest ecosystem in the humid subtropics
Geißler, Christian; Kühn, Peter; Scholten, Thomas
2010-05-01
After decades of research it is generally accepted that vegetation is a key factor in controlling soil erosion. Therefore, in ecosystems where erosion is a serious problem, afforestation is a common measure against erosion. Most of the studies in the last decades focused on agricultural systems and less attention was paid to natural systems. To understand the mechanisms preventing soil erosion in natural systems the processes have to be studied in detail and gradually. The first step and central research question is on how the canopies of the tree layer alter the properties of rainfall and generate throughfall. Kinetic energy is a widely used parameter to estimate the erosion potential of open field rainfall and throughfall. In the past, numerous studies have shown that vegetation of a certain height enhances the kinetic energy under the canopy (Chapman 1948, Mosley 1982, Vis 1986, Hall & Calder 1993, Nanko et al. 2006, Nanko et al. 2008) in relation to open field rainfall. This is mainly due to a shift in the drop size distribution to less but larger drops possessing a higher amount of kinetic energy. In vital forest ecosystems lower vegetation (shrubs, herbs) as well as a continuous litter layer protects the forest soil from the impact of large drops. The influence of biodiversity, specific forest stands or single species in this process system is still in discussion. In the present study calibrated splash cups (after Ellison 1947, Geißler et al. under review) have been used to detect differences in kinetic energy on the scale of specific species and on the scale of forest stands of contrasting age and biodiversity in a natural forest ecosystem. The splash cups have been calibrated experimentally using a laser disdrometer. The results show that the kinetic energy of throughfall produced by the tree layer increases with the age of the specific forest stand. The average throughfall kinetic energy (J m-2) is about 2.6 times higher in forests than under open field
Buoyant production and consumption of turbulence kinetic energy in cloud-topped mixed layers
Randall, D. A.
1984-01-01
It is pointed out that studies of the entraining planetary boundary layer (PBL) have generally emphasized the role of buoyancy fluxes in driving entrainment. The buoyancy flux is proportional to the rate of conversion of the potential energy of the mean flow into the kinetic energy of the turbulence. It is not unusual for conversion to proceed in both directions simultaneously. This occurs, for instance, in both clear and cloudy convective mixed layers which are capped by inversions. A partitioning of the net conversion into positive parts, generating turbulence kinetic energy (TKE), and negative parts (TKE-consuming), would make it possible to include the positive part in the gross production rate, and closure would be achieved. Three different approaches to partitioning have been proposed. The present investigation is concerned with a comparison of the three partitioning theories. Particular attention is given to the cloud-topped mixed layer because in this case the differences between two partitioning approaches are most apparent.
Electron scattering as a tool to study zero-point kinetic energies of atoms in molecules
Moreh, R.; Finkelstein, Y.; Vos, M.
2015-07-01
High resolution electron compton scattering (ECS) is being used to study the atomic momentum distributions and hence the zero-point kinetic energies (ZPKE) of the scattering atoms. Such studies have shown that the scattering is from a single atom of the scattering sample. For an electron beam with a well defined incident energy, the scattered electron energy at any angle from each atomic species is Doppler broadened. The broadening reflects the atomic momentum distribution contributed by both the internal and external motions of the molecular system. By measuring the Doppler broadening of the scattered electron lines it was possible to determine the kinetic energy of the scattering atom including that of its zero-point motion. Thus, the atomic kinetic energies in gases such as H2, D2, HD, CH4 and in H2O, D2O and NH3 were measured and compared with those calculated semi-empirically using the measured optical infra red (IR) and Raman frequencies of the internal vibrations of the molecules. In general, good agreement between the measured and calculated values was found. Electron scattering was also used to study the ratio of e-scattering intensities from the H- and O-atoms in water (H2O), where some anomalies were reported to exist.
Electron scattering as a tool to study zero-point kinetic energies of atoms in molecules
International Nuclear Information System (INIS)
High resolution electron compton scattering (ECS) is being used to study the atomic momentum distributions and hence the zero-point kinetic energies (ZPKE) of the scattering atoms. Such studies have shown that the scattering is from a single atom of the scattering sample. For an electron beam with a well defined incident energy, the scattered electron energy at any angle from each atomic species is Doppler broadened. The broadening reflects the atomic momentum distribution contributed by both the internal and external motions of the molecular system. By measuring the Doppler broadening of the scattered electron lines it was possible to determine the kinetic energy of the scattering atom including that of its zero-point motion. Thus, the atomic kinetic energies in gases such as H2, D2, HD, CH4 and in H2O, D2O and NH3 were measured and compared with those calculated semi-empirically using the measured optical infra red (IR) and Raman frequencies of the internal vibrations of the molecules. In general, good agreement between the measured and calculated values was found. Electron scattering was also used to study the ratio of e-scattering intensities from the H- and O-atoms in water (H2O), where some anomalies were reported to exist
Electron scattering as a tool to study zero-point kinetic energies of atoms in molecules
Energy Technology Data Exchange (ETDEWEB)
Moreh, R., E-mail: moreh@bgu.ac.il [Physics Department, Ben-Gurion University of the Negev, Beer-Sheva 84105 (Israel); Finkelstein, Y. [Nuclear Research Center – Negev, Beer-Sheva 84190 (Israel); Vos, M. [Atomic and Molecular Physics Laboratories, Australian National University, Canberra (Australia)
2015-07-01
High resolution electron compton scattering (ECS) is being used to study the atomic momentum distributions and hence the zero-point kinetic energies (ZPKE) of the scattering atoms. Such studies have shown that the scattering is from a single atom of the scattering sample. For an electron beam with a well defined incident energy, the scattered electron energy at any angle from each atomic species is Doppler broadened. The broadening reflects the atomic momentum distribution contributed by both the internal and external motions of the molecular system. By measuring the Doppler broadening of the scattered electron lines it was possible to determine the kinetic energy of the scattering atom including that of its zero-point motion. Thus, the atomic kinetic energies in gases such as H{sub 2}, D{sub 2}, HD, CH{sub 4} and in H{sub 2}O, D{sub 2}O and NH{sub 3} were measured and compared with those calculated semi-empirically using the measured optical infra red (IR) and Raman frequencies of the internal vibrations of the molecules. In general, good agreement between the measured and calculated values was found. Electron scattering was also used to study the ratio of e-scattering intensities from the H- and O-atoms in water (H{sub 2}O), where some anomalies were reported to exist.
Rock Cutting Depth Model Based on Kinetic Energy of Abrasive Waterjet
Oh, Tae-Min; Cho, Gye-Chun
2016-03-01
Abrasive waterjets are widely used in the fields of civil and mechanical engineering for cutting a great variety of hard materials including rocks, metals, and other materials. Cutting depth is an important index to estimate operating time and cost, but it is very difficult to predict because there are a number of influential variables (e.g., energy, geometry, material, and nozzle system parameters). In this study, the cutting depth is correlated to the maximum kinetic energy expressed in terms of energy (i.e., water pressure, water flow rate, abrasive feed rate, and traverse speed), geometry (i.e., standoff distance), material (i.e., α and β), and nozzle system parameters (i.e., nozzle size, shape, and jet diffusion level). The maximum kinetic energy cutting depth model is verified with experimental test data that are obtained using one type of hard granite specimen for various parameters. The results show a unique curve for a specific rock type in a power function between cutting depth and maximum kinetic energy. The cutting depth model developed here can be very useful for estimating the process time when cutting rock using an abrasive waterjet.
On the ultrafast kinetics of the energy and electron transfer reactions in photosystem I
Energy Technology Data Exchange (ETDEWEB)
Slavov, Chavdar Lyubomirov
2009-07-09
The subject of the current work is one of the main participants in the light-dependent phase of oxygenic photosynthesis, Photosystem I (PS I). This complex carries an immense number of cofactors: chlorophylls (Chl), carotenoids, quinones, etc, which together with the protein entity exhibit several exceptional properties. First, PS I has an ultrafast light energy trapping kinetics with a nearly 100% quantum efficiency. Secondly, both of the electron transfer branches in the reaction center are suggested to be active. Thirdly, there are some so called 'red' Chls in the antenna system of PS I, absorbing light with longer wavelengths than the reaction center. These 'red' Chls significantly modify the trapping kinetics of PS I. The purpose of this thesis is to obtain better understanding of the above-mentioned, specific features of PS I. This will not merely cast more light on the mechanisms of energy and electron transfer in the complex, but also will contribute to the future developments of optimized artificial light-harvesting systems. In the current work, a number of PS I complexes isolated from different organisms (Thermosynechococcus elongatus, Chlamydomonas reinhardtii, Arabidopsis thaliana) and possessing distinctive features (different macroorganisation, monomers, trimers, monomers with a semibelt of peripheral antenna attached; presence of 'red' Chls) is investigated. The studies are primarily focused on the electron transfer kinetics in each of the cofactor branches in the PS I reaction center, as well as on the effect of the antenna size and the presence of 'red' Chls on the trapping kinetics of PS I. These aspects are explored with the help of several ultrafast optical spectroscopy methods: (i) time-resolved fluorescence ? single photon counting and synchroscan streak camera; and (ii) ultrafast transient absorption. Physically meaningful information about the molecular mechanisms of the energy trapping in PS I is
Kinetic and potential parts of nuclear symmetry energy: the role of Fock terms
Zhao, Qian; Sun, Bao Yuan; Long, Wen Hui
2015-09-01
The density dependence of nuclear symmetry energy is studied within the covariant density functional (CDF) theory in terms of the kinetic energy, isospin-singlet, and isospin-triplet potential energy parts of the energy density functional. When the Fock diagram is introduced, it is found that both isospin-singlet and isospin-triplet components of the potential energy play an important role in determining the symmetry energy. At high densities, a strong density-dependent behavior is revealed in the isospin-triplet potential part of the symmetry energy. In addition, the inclusion of the Fock terms in the CDF theory reduces the kinetic part of the symmetry energy and may lead to negative values at the supranuclear density region, which is regarded partly as the effect of the nuclear tensor-force components. The results demonstrate the importance of the Fock diagram in the CDF theory on the isospin properties of the in-medium nuclear force at high densities, especially from the isoscalar-meson coupling channels.
Kinetic energy recovery turbine technology: resource assessment and site development strategy
Energy Technology Data Exchange (ETDEWEB)
Briand, Marie-Helene; Ng, Karen
2010-09-15
New technologies to extract readily available energy from waves, tides and river flow are being developed and are promising but are still at the demonstration stage. Harnessing kinetic energy from currents (hydrokinetic power) is considered an attractive and cost-effective renewable energy solution to replace thermal generation without requiring construction of a dam or large civil works. The nature of this innovative hydrokinetic technology requires an adaptation of conventional approach to project engineering and environmental impact studies. This paper presents the approach developed by RSW to design a hydrokinetic site in the riverine environment, from resource assessment to detailed engineering design.
Metastable anions of dinitrobenzene: Resonances for electron attachment and kinetic energy release
Mauracher, Andreas; Denifl, S.; Edtbauer, A.; Hager, M; Probst, M.; Echt, O.; Mark, T.D.; Scheier, P.; Field, Thomas; Graupner, Karola
2010-01-01
Attachment of free, low-energy electrons to dinitrobenzene (DNB) in the gas phase leads to DNB as well as several fragment anions. DNB, (DNB-H), (DNB-NO), (DNB-2NO), and (DNB-NO2) are found to undergo metastable (unimolecular) dissociation. A rich pattern of resonances in the yield of these metastable reactions versus electron energy is observed; some resonances are highly isomer-specific. Most metastable reactions are accompanied by large average kinetic energy releases (KER) that range from...
Design, analysis and testing of a piezoelectric flex transducer for harvesting bio-kinetic energy
Daniels, A.; Zhu, M.; Tiwari, A.
2013-12-01
The increasing prevalence of low power consuming electronics brings greater potential to mobile energy harvesting devices as a possible power source. A new piezoelectric energy harvesting device, called the piezoelectric flex transducer (PFT), is presented and developed. A Finite Element Model (FEM) was developed to design and analyse the PFT. The PFT consists of a piezoelectric element sandwiched between substrate layers and metal endcaps that are able to amplify the axial force on the piezoelectric element. Based on the concept of the Cymbal transducer, the PFT can withstand higher forces, was retrofitted into a shoe and used to power a wireless sensor module whilst the subject with a body weight of 760N was wearing the shoe and ran at 3.1mph (1.4HZ on shoe), the PFT produced an average maximum power of 2.5mW (over 2MΩ load).
Design, analysis and testing of a piezoelectric flex transducer for harvesting bio-kinetic energy
International Nuclear Information System (INIS)
The increasing prevalence of low power consuming electronics brings greater potential to mobile energy harvesting devices as a possible power source. A new piezoelectric energy harvesting device, called the piezoelectric flex transducer (PFT), is presented and developed. A Finite Element Model (FEM) was developed to design and analyse the PFT. The PFT consists of a piezoelectric element sandwiched between substrate layers and metal endcaps that are able to amplify the axial force on the piezoelectric element. Based on the concept of the Cymbal transducer, the PFT can withstand higher forces, was retrofitted into a shoe and used to power a wireless sensor module whilst the subject with a body weight of 760N was wearing the shoe and ran at 3.1mph (1.4HZ on shoe), the PFT produced an average maximum power of 2.5mW (over 2MΩ load)
The Harmonic Picture of Nuclear Mean Kinetic Energies in Heavy Water
International Nuclear Information System (INIS)
This paper presents a study of the total mean kinetic energy, (EK), and of individual projections along a given molecular axis, (EK)α, for D and O nuclei in D2O, derived using a harmonic model. Our theoretical approach assumes decoupling amongst translational, rotational and vibrational modes. Resulting values of these dynamical quantities are discussed in terms of the anisotropy of the quantum kinetic energy tensor, its relation to the local potential, and deviations from the hypothesis of harmonicity and mode decoupling. Results are compared with corresponding quantities obtained from Deep Inelastic Neutron Scattering experiments performed on liquid and solid D2O, where the short-time dynamics and local environment of D and O atoms were probed. The present study confirms an overall picture where even small changes in the short-range environment of D and O nuclei have a strong influence on the quantum behaviour of heavy water
How to measure kinetic energy of the heavy quark inside B mesons?
Bigi, Ikaros I; Shifman, M; Uraltsev, N; Vainshtein, A I
1994-01-01
We discuss how one can determine the average kinetic energy of the heavy quark inside heavy mesons from differential distributions in B decays. A new, so-called third, sum rule for the b\\rightarrow c transition is derived in the small velocity (SV) limit. Using this sum rule and the existing data on the momentum dependence in the B\\rightarrow D^* transition (the slope of the Isgur-Wise function) we obtain a new lower bound on the parameter \\mu_\\pi^2 = (2M_B)^{-1}\\langle B |\\bar b (i\\vec{D})^2 b |B\\rangle proportional to the average kinetic energy of b quark inside B meson. The existing data suggest \\mu_\\pi^2 > 0.4~GeV^2 and (from the ``optical'' sum rule) \\overline{\\Lambda} > 500 MeV, albeit with some numerical uncertainties.
Total kinetic energy distribution of fission fragments in 6,7Li + 238U reactions
International Nuclear Information System (INIS)
The shape and width of fission-fragment (FF) mass and kinetic energy distribution provides a lot of information on the fission reaction mechanism and the structure of the compound nucleus (CN), the fragments as well as the interacting nuclei. The shape of the mass distribution of the fission fragments for the actinides induced by the proton or neutron is known to change with the incident energy. At low energies, it shows a double humped distribution which changes slowly to a single humped distribution as energy increases. However, for a reaction involving a weakly bound projectile (i.e., 6Li + 232Th), a sharp change in the shape of the mass distribution with energy was observed. The sharp increase in the peak to valley ratio (P:V) in the fission-fragment mass distribution in 6Li + 232Th reaction by Itkis et al. and in 6,7Li + 238U reactions by Santra et al. was concluded to be due to the reduced energy transfer to the composite system caused by incomplete fusion (ICF) of alpha or deuteron/triton followed by fissions. Total Kinetic Energy (TKE) distribution of fission fragments is another important observable on which the effect of projectile breakup is not explored yet. In this contribution, the study of breakup/transfer effect on average TKE distribution for 6,7Li + 238U reactions is presented
Barkan, Roy
2015-01-01
The general circulation of the ocean is forced by surface fluxes of momentum, heat, and freshwater at basin scales. The kinetic (E_k) and available potential (E_a) energy sources associated with these external forces drive a circulation which exhibits flow features that vary on a wide range of spatial and temporal scales. Understanding how the different forcing mechanisms lead to the observed large-scale ocean circulation patterns and to what degree do the various smaller scale processes modi...
Age-related changes in intraventricular kinetic energy: a physiological or pathological adaptation?
Wong, James; Chabiniok, Radomir; deVecchi, Adelaide; Dedieu, Nathalie; Sammut, Eva; Schaeffter, Tobias
2016-01-01
Aging has important deleterious effects on the cardiovascular system. We sought to compare intraventricular kinetic energy (KE) in healthy subjects of varying ages with subjects with ventricular dysfunction to understand if changes in energetic momentum may predispose individuals to heart failure. Four-dimensional flow MRI was acquired in 35 healthy subjects (age: 1–67 yr) and 10 patients with left ventricular (LV) dysfunction (age: 28–79 yr). Healthy subjects were divided into age quartiles (1st quartile: pathology. PMID:26747496
ENERGY TRANSFER IN TRIMERIC C-PHYCOCYANIN STUDIED BY PICOSECOND FLUORESCENCE KINETICS
WENDLER, J.; John, Wolfhart; Scheer, Hugo; Holzwarth, A. R.
1986-01-01
The excited state kinetics of trimeric C-phycocyanin from Mastigocladus laminosus has been measured as a function of the emission and excitation wavelength by the single-photon timing technique with picosecond resolution and simultaneous data analysis. A fast decay component of 22 ps (C-phycocyanin with linker peptides) and 36 ps (C-phycocyanin lacking linker peptides) is attributed to efficient energy transfer from sensitizing to fluorescing chromophores. At long detection wavelengths the fa...
Revisiting the density scaling of the non-interacting kinetic energy.
Borgoo, Alex; Teale, Andrew M; Tozer, David J
2014-07-28
Scaling relations play an important role in the understanding and development of approximate functionals in density functional theory. Recently, a number of these relationships have been redefined in terms of the Kohn-Sham orbitals [Calderín, Phys. Rev. A: At., Mol., Opt. Phys., 2013, 86, 032510]. For density scaling the author proposed a procedure involving a multiplicative scaling of the Kohn-Sham orbitals whilst keeping their occupation numbers fixed. In the present work, the differences between this scaling with fixed occupation numbers and that of previous studies, where the particle number change implied by the scaling was accommodated through the use of the grand canonical ensemble, are examined. We introduce the terms orbital and ensemble density scaling for these approaches, respectively. The natural ambiguity of the density scaling of the non-interacting kinetic energy functional is examined and the ancillary definitions implicit in each approach are highlighted and compared. As a consequence of these differences, Calderín recovered a homogeneity of degree 1 for the non-interacting kinetic energy functional under orbital scaling, contrasting recent work by the present authors [J. Chem. Phys., 2012, 136, 034101] where the functional was found to be inhomogeneous under ensemble density scaling. Furthermore, we show that the orbital scaling result follows directly from the linearity and the single-particle nature of the kinetic energy operator. The inhomogeneity of the non-interacting kinetic energy functional under ensemble density scaling can be quantified by defining an effective homogeneity. This quantity is shown to recover the homogeneity values for important approximate forms that are exact for limiting cases such as the uniform electron gas and one-electron systems. We argue that the ensemble density scaling provides more insight into the development of new functional forms. PMID:24710656
Kinetic theory of binary particles with unequal mean velocities and non-equipartition energies
Mei, Yifeng; Chen, Yanpei; Wang, Wei
2015-01-01
The hydrodynamic conservation equations and constitutive relations for a binary granular mixture composed of smooth, nearly elastic, hard spheres with non-equipartition energies and different mean velocities are derived. This research is aimed to build three-dimensional kinetic theory to characterize the behaviors of two species of particles suffering different forces. The standard Enskog method is employed assuming a Maxwell velocity distribution for each species of particles. The collision ...
Membrane Bending Energy and Fusion Pore Kinetics in Ca2+-Triggered Exocytosis
Zhang, Zhen; Jackson, Meyer B.
2010-01-01
A fusion pore composed of lipid is an obligatory kinetic intermediate of membrane fusion, and its formation requires energy to bend membranes into highly curved shapes. The energetics of such deformations in viral fusion is well established, but the role of membrane bending in Ca2+-triggered exocytosis remains largely untested. Amperometry recording showed that during exocytosis in chromaffin and PC12 cells, fusion pores formed by smaller vesicles dilated more rapidly than fusion pores formed...
Montoya, M; Rojas, J
2007-01-01
The mass and kinetic energy distribution of nuclear fragments from thermal neutron induced fission of 235U have been studied using a Monte-Carlo simulation. Besides reproducing the pronounced broadening on the standard deviation of the final fragment kinetic energy distribution $\\sigma_{e}(m)$ around the mass number m = 109, our simulation also produces a second broadening around m = 125, that is in agreement with the experimental data obtained by Belhafaf et al. These results are consequence of the characteristics of the neutron emission, the variation in the primary fragment mean kinetic energy and the yield as a function of the mass.
Measuring kinetic energy changes in the mesoscale with low acquisition rates
Energy Technology Data Exchange (ETDEWEB)
Roldán, É. [ICFO–Institut de Ciències Fotòniques, Mediterranean Technology Park, Av. Carl Friedrich Gauss 3, 08860 Castelldefels (Barcelona) (Spain); GISC–Grupo Interdisciplinar de Sistemas Complejos, Madrid (Spain); Martínez, I. A.; Rica, R. A., E-mail: rul@ugr.es [ICFO–Institut de Ciències Fotòniques, Mediterranean Technology Park, Av. Carl Friedrich Gauss 3, 08860 Castelldefels (Barcelona) (Spain); Dinis, L. [GISC–Grupo Interdisciplinar de Sistemas Complejos, Madrid (Spain); Departamento de Física Atómica, Molecular y Nuclear, Universidad Complutense de Madrid, 28040 Madrid (Spain)
2014-06-09
We report on the measurement of the average kinetic energy changes in isothermal and non-isothermal quasistatic processes in the mesoscale, realized with a Brownian particle trapped with optical tweezers. Our estimation of the kinetic energy change allows to access to the full energetic description of the Brownian particle. Kinetic energy estimates are obtained from measurements of the mean square velocity of the trapped bead sampled at frequencies several orders of magnitude smaller than the momentum relaxation frequency. The velocity is tuned applying a noisy electric field that modulates the amplitude of the fluctuations of the position and velocity of the Brownian particle, whose motion is equivalent to that of a particle in a higher temperature reservoir. Additionally, we show that the dependence of the variance of the time-averaged velocity on the sampling frequency can be used to quantify properties of the electrophoretic mobility of a charged colloid. Our method could be applied to detect temperature gradients in inhomogeneous media and to characterize the complete thermodynamics of biological motors and of artificial micro and nanoscopic heat engines.
Measuring kinetic energy changes in the mesoscale with low acquisition rates
International Nuclear Information System (INIS)
We report on the measurement of the average kinetic energy changes in isothermal and non-isothermal quasistatic processes in the mesoscale, realized with a Brownian particle trapped with optical tweezers. Our estimation of the kinetic energy change allows to access to the full energetic description of the Brownian particle. Kinetic energy estimates are obtained from measurements of the mean square velocity of the trapped bead sampled at frequencies several orders of magnitude smaller than the momentum relaxation frequency. The velocity is tuned applying a noisy electric field that modulates the amplitude of the fluctuations of the position and velocity of the Brownian particle, whose motion is equivalent to that of a particle in a higher temperature reservoir. Additionally, we show that the dependence of the variance of the time-averaged velocity on the sampling frequency can be used to quantify properties of the electrophoretic mobility of a charged colloid. Our method could be applied to detect temperature gradients in inhomogeneous media and to characterize the complete thermodynamics of biological motors and of artificial micro and nanoscopic heat engines.
Vector modeling and track simulation in axial turn-milling motion
Institute of Scientific and Technical Information of China (English)
JIANG Zeng-hui; JIA Chun-de
2005-01-01
Through vector analysis the kinetic vector model is built in a machining cylinder surface through axial turn-milling. When building a kinetic vector model in the machining field, machining through axial turn-milling and using equilateral triangles and square prism surfaces, the kinetic vector model is given any equilateral polygon prismic surface. Kinetic tracks are simulated through these kinetic models respectively, thus it can be seen that the axial turn-milling is a very effective method in manufacturing any equilateral, polygon, prismic surface.
Axially symmetric rotating traversable wormholes
Kuhfittig, P K F
2003-01-01
This paper generalizes the static and spherically symmetric traversable wormhole geometry to a rotating axially symmetric one with a time-dependent angular velocity by means of an exact solution. It was found that the violation of the weak energy condition, although unavoidable, is considerably less severe than in the static spherically symmetric case. The radial tidal constraint is more easily met due to the rotation. Similar improvements are seen in one of the lateral tidal constraints. The magnitude of the angular velocity may have little effect on the weak energy condition violation for an axially symmetric wormhole. For a spherically symmetric one, however, the violation becomes less severe with increasing angular velocity. The time rate of change of the angular velocity, on the other hand, was found to have no effect at all. Finally, the angular velocity must depend only on the radial coordinate, confirming an earlier result.
Wang, Y Y; Grygiel, C; Dufour, C; Sun, J R; Wang, Z G; Zhao, Y T; Xiao, G Q; Cheng, R; Zhou, X M; Ren, J R; Liu, S D; Lei, Y; Sun, Y B; Ritter, R; Gruber, E; Cassimi, A; Monnet, I; Bouffard, S; Aumayr, F; Toulemonde, M
2014-01-01
Modification of surface and bulk properties of solids by irradiation with ion beams is a widely used technique with many applications in material science. In this study, we show that nano-hillocks on CaF2 crystal surfaces can be formed by individual impact of medium energy (3 and 5 MeV) highly charged ions (Xe(22+) to Xe(30+)) as well as swift (kinetic energies between 12 and 58 MeV) heavy xenon ions. For very slow highly charged ions the appearance of hillocks is known to be linked to a threshold in potential energy (Ep) while for swift heavy ions a minimum electronic energy loss per unit length (Se) is necessary. With our results we bridge the gap between these two extreme cases and demonstrate, that with increasing energy deposition via Se the Ep-threshold for hillock production can be lowered substantially. Surprisingly, both mechanisms of energy deposition in the target surface seem to contribute in an additive way, which can be visualized in a phase diagram. We show that the inelastic thermal spike model, originally developed to describe such material modifications for swift heavy ions, can be extended to the case where both kinetic and potential energies are deposited into the surface. PMID:25034006
Kinetic Energy Distribution of H(2p) Atoms from Dissociative Excitation of H2
Ajello, Joseph M.; Ahmed, Syed M.; Kanik, Isik; Multari, Rosalie
1995-01-01
The kinetic energy distribution of H(2p) atoms resulting from electron impact dissociation of H2 has been measured for the first time with uv spectroscopy. A high resolution uv spectrometer was used for the measurement of the H Lyman-alpha emission line profiles at 20 and 100 eV electron impact energies. Analysis of the deconvolved 100 eV line profile reveals the existence of a narrow line peak and a broad pedestal base. Slow H(2p) atoms with peak energy near 80 meV produce the peak profile, which is nearly independent of impact energy. The wings of H Lyman-alpha arise from dissociative excitation of a series of doubly excited Q(sub 1) and Q(sub 2) states, which define the core orbitals. The fast atom energy distribution peaks at 4 eV.
International Nuclear Information System (INIS)
The description of an experimental set-up for the study of the excitation energy distribution of fission fragments by means of coincident measurement of fission neutrons is presented. For every fission event the kinetic energy and mass of both fragments are registered simultaneously with the number of prompt neutrons emitted by each of the complementary fission fragments. With this set-up, the fission fragments are detected by a twin ionization chamber and the neutrons - by two large Gd-loaded liquid scintillator tanks. (author)
Optimization of kinetic energy harvesters design for fully implantable Cochlear Implants.
Sudano, A; Accoto, D; Francomano, M T; Salvinelli, F; Guglielmelli, E
2011-01-01
Fully implantable Cochlear Implants (CIs) would represent a tremendous advancement in terms of quality of life, comfort and cosmetics, for patients with profound sensorineural deafness. One of the main challenges involved in the development of such implants consists of finding a power supply means which does not require recharging. To this aim an inertial Energy Harvester (EH), exploiting the kinetic energy produced by vertical movements of the head during walking, has been investigated. Compared to existing devices, the EH needs to exploit very low frequency vibrations (Genetic Algorithms (GAs). The robustness of the solution is also evaluated. PMID:22256117
Total kinetic energy release in the fast neutron-induced fission of $^{235}$U
Yanez, R; Loveland, W.; King, J.; Barrett, J. S.; Fotiades, N.; Lee, H. Y.
2015-01-01
We have measured the total kinetic energy (TKE) release for the $^{235}$U(n,f) reaction for $E_{n}$=2-100 MeV using the 2E method with an array of Si PIN diode detectors. The neutron energies were determined by time of flight measurements using the white spectrum neutron beam at the LANSCE facility. (To calibrate the apparatus, the TKE release for $^{235}$U(n$_{th}$,f) was also measured using a thermal neutron beam from the OSU TRIGA reactor). The TKE decreases non-linearly from 169.0 MeV to ...
Total kinetic energy release in the fast neutron-induced fission of $^{235}$U
Yanez, R; Loveland, W.; King, J.; Barrett, J. S.; Fotiades, N.; Lee, H. Y.
2016-01-01
We have measured the total kinetic energy (TKE) release for the $^{235}$U(n,f) reaction for $E_{n}$=2-100 MeV using the 2E method with an array of Si PIN diode detectors. The neutron energies were determined by time of flight measurements using the white spectrum neutron beam at the LANSCE facility. To benchmark the TKE measurement, the TKE release for $^{235}$U(n$_{th}$,f) was also measured using a thermal neutron beam from the Oregon State University TRIGA reactor, giving pre-neutron emissi...
International Nuclear Information System (INIS)
The mass and kinetic energy distributions of fragments from thermal neutron induced fission of 233U have been studied using a Monte-Carlo simulation. In our previous work [1] we reproduce the two pronounced broadenings in the standard deviation (SD) of the kinetic energy distribution of the final fragment at mass number around m=109, and m=125, respectively, which is agreement with the experimental data obtained by Belhafaf et al. [2] (author).
Chemical bond as a test of density-gradient expansions for kinetic and exchange energies
International Nuclear Information System (INIS)
Errors in kinetic and exchange contributions to the molecular bonding energy are assessed for approximate density functionals by reference to near-exact Hartree-Fock values. From the molecular calculations of Allan et al. and of Lee and Ghosh, it is demonstrated that the density-gradient expansion does not accurately describe the noninteracting kinetic contribution to the bonding energy, even when this expansion is carried to fourth order and applied in its spin-density-functional form to accurate Hartree-Fock densities. In a related study, it is demonstrated that the overbinding of molecules such as N2 and F2, which occurs in the local-spin-density (LSD) approximation for the exchange-correlation energy, is not attributable to errors in the self-consistent LSD densities. Contrary to expectations based upon the Gunnarsson-Jones nodality argument, it is found that the LSD approximation for the exchange energy can seriously overbind a molecule even when bonding does not create additional nodes in the occupied valence orbitals. LSD and exact values for the exchange contribution to the bonding energy are displayed and discussed for several molecules
International Nuclear Information System (INIS)
The purpose of this calculation is to develop axial profiles for estimating the axial variation in burnup of a boiling water reactor (BWR) assembly spent nuclear fuel (SNF) given the average burnup of an assembly. A discharged fuel assembly typically exhibits higher burnup in the center and lower burnup at the ends of the assembly. Criticality safety analyses taking credit for SNF burnup must account for axially varying burnup relative to calculations based on uniformly distributed assembly average burnup due to the under-burned tips. Thus, accounting for axially varying burnup in criticality analyses is also referred to as accounting for the ''end effect'' reactivity. The magnitude of the reactivity change due to ''end effect'' is dependent on the initial assembly enrichment, the assembly average burnup, and the particular axial profile characterizing the burnup distribution. The set of bounding axial profiles should incorporate multiple BWR core designs and provide statistical confidence (95 percent confidence that 95 percent of the population is bound by the profile) that end nodes are conservatively represented. The profiles should also conserve the overall burnup of the fuel assembly. More background on BWR axial profiles is provided in Attachment I
Energy Technology Data Exchange (ETDEWEB)
J. Huffer
2004-09-28
The purpose of this calculation is to develop axial profiles for estimating the axial variation in burnup of a boiling water reactor (BWR) assembly spent nuclear fuel (SNF) given the average burnup of an assembly. A discharged fuel assembly typically exhibits higher burnup in the center and lower burnup at the ends of the assembly. Criticality safety analyses taking credit for SNF burnup must account for axially varying burnup relative to calculations based on uniformly distributed assembly average burnup due to the under-burned tips. Thus, accounting for axially varying burnup in criticality analyses is also referred to as accounting for the ''end effect'' reactivity. The magnitude of the reactivity change due to ''end effect'' is dependent on the initial assembly enrichment, the assembly average burnup, and the particular axial profile characterizing the burnup distribution. The set of bounding axial profiles should incorporate multiple BWR core designs and provide statistical confidence (95 percent confidence that 95 percent of the population is bound by the profile) that end nodes are conservatively represented. The profiles should also conserve the overall burnup of the fuel assembly. More background on BWR axial profiles is provided in Attachment I.
Enzymatic Kinetic Isotope Effects from Path-Integral Free Energy Perturbation Theory.
Gao, J
2016-01-01
Path-integral free energy perturbation (PI-FEP) theory is presented to directly determine the ratio of quantum mechanical partition functions of different isotopologs in a single simulation. Furthermore, a double averaging strategy is used to carry out the practical simulation, separating the quantum mechanical path integral exactly into two separate calculations, one corresponding to a classical molecular dynamics simulation of the centroid coordinates, and another involving free-particle path-integral sampling over the classical, centroid positions. An integrated centroid path-integral free energy perturbation and umbrella sampling (PI-FEP/UM, or simply, PI-FEP) method along with bisection sampling was summarized, which provides an accurate and fast convergent method for computing kinetic isotope effects for chemical reactions in solution and in enzymes. The PI-FEP method is illustrated by a number of applications, to highlight the computational precision and accuracy, the rule of geometrical mean in kinetic isotope effects, enhanced nuclear quantum effects in enzyme catalysis, and protein dynamics on temperature dependence of kinetic isotope effects. PMID:27498645
Institute of Scientific and Technical Information of China (English)
Gamal G.L. Nashed
2011-01-01
A theory of (4+1)-dimensional gravity is developed on the basis of the teleparallel theory equivalent to general relativity.The fundamental gravitational field variables are the five-dimensional vector fields (pentad),defined globally on a manifold M,and gravity is attributed to the torsion.The Lagrangian density is quadratic in the torsion tensor.We then give the exact five-dimensional solution.The solution is a generalization of the familiar Schwarzschild and Kerr solutions of the four-dimensional teleparallel equivalent of general relativity.We also use the definition of the gravitational energy to calculate the energy and the spatial momentum.
Wang, Y.Y.; Grygiel, C.; Dufour, C; J. R. Sun; Wang, Z.G.; Zhao, Y. T.; G. Q. Xiao; Cheng, R.; Zhou, X. M.; Ren, J. R.; Liu, S. D.; Lei, Y.; Sun, Y. B.; Ritter, R.; E. Gruber
2014-01-01
Modification of surface and bulk properties of solids by irradiation with ion beams is a widely used technique with many applications in material science. In this study, we show that nano-hillocks on CaF2 crystal surfaces can be formed by individual impact of medium energy (3 and 5 MeV) highly charged ions (Xe22+ to Xe30+) as well as swift (kinetic energies between 12 and 58 MeV) heavy xenon ions. For very slow highly charged ions the appearance of hillocks is known to be linked to a threshol...
Institute of Scientific and Technical Information of China (English)
无
2011-01-01
[Objective] The research aimed to study the structure and propagation characteristics of climatological mean kinetic energy of disturbance of intraseasonal oscillation in Asian summer monsoon zone. [Method] When South China Sea monsoon started to break out, the kinetic energy of intraseasonal oscillation disturbance in the monsoon zone was analyzed, especially the researches about the variation of South China Sea monsoon, the development of Indian monsoon and the advancement of East Asian monsoon. [Result] ...
Kinetic energy distributions of neutral In and In{sub 2} sputtered by polyatomic ion bombardment
Energy Technology Data Exchange (ETDEWEB)
Samartsev, A.V. [Department of Physics, University of Duisburg-Essen, 47048 Duisburg (Germany); Wucher, A. [Department of Physics, University of Duisburg-Essen, 47048 Duisburg (Germany)]. E-mail: wucher@uni-essen.de
2006-07-30
Kinetic energy distributions of neutral In monomers and In{sub 2} dimers sputtered from a polycrystalline indium surface under bombardment with 5 keV/atom Au{sub 1} {sup -} and Au{sub 2} {sup -} projectiles have been investigated by means of laser postionization time-of-flight mass spectrometry. Results show that 5 keV Au{sub 1} bombardment leads to results in full compliance with linear cascade sputtering theory. For polyatomic ion bombardment, we find a clear transition to a collisional spike dominated emission process. The spike contribution appears as a low-energy part in the sputtered flux which increases with increasing projectile nuclearity and energy. We show that, the velocity spectrum associated with the low-energy contribution is virtually identical for sputtered monomers and dimers. This finding has important implications with respect to the particle emission mechanism under polyatomic projectile bombardment.
Ion kinetic energies in inductively coupled plasma/mass spectrometry (ICP-MS)
International Nuclear Information System (INIS)
Ion kinetic energies in an inductively coupled plasma/mass spectrometer (ICP-MS) system have been measured with the use of a retarding potential on the analyzing quadrupole. The energies differ markedly from those previously reported in the literature. This is attributed to the elimination of any arcing of the ICP to the sampling orifice or skimmer of the ICP-MS system. In the absence of secondary discharge effects, the ion energies increase with the mass of the ion and are consistent with those expected from molecular beam sampling from a plasma with a temperature of --5000 K and a potential of --2 V. Ion energies are found to be virtually independent of aerosol gas flow, plasma power, and sample matrix composition, allowing independent optimization of plasma parameters and ion optics
Notari, Alessio
2016-01-01
We analyze in detail the background cosmological evolution of a scalar field coupled to a massless abelian gauge field through an axial term $\\frac{\\phi}{f_\\gamma} F \\tilde{F}$, such as in the case of an axion. Gauge fields in this case are known to experience tachyonic growth and therefore can backreact on the background as an effective dissipation into radiation energy density $\\rho_R$, which which can lead to inflation without the need of a flat potential. We analyze the system, for momenta $k$ smaller than the cutoff $f_\\gamma$, including numerically the backreaction. We consider the evolution from a given static initial condition and explicitly show that, if $f_\\gamma$ is smaller than the field excursion $\\phi_0$ by about a factor of at least ${\\cal O} (20)$, there is a friction effect which turns on before that the field can fall down and which can then lead to a very long stage of inflation with a generic potential. In addition we find superimposed oscillations, which would get imprinted on any kind of...
International Nuclear Information System (INIS)
We study two families of approximate nonlocal kinetic-energy functionals that include a full von Weizsaecker functional, and that have nonlocal terms with the mathematical structure of the Thomas-Fermi functional. The functionals recover the exact kinetic energy and the linear response function of a homogeneous electron system. The first family is a generalization of a successful previous nonlocal functional. The second family is proposed in the paper, and is designed to obtain functionals suitable for use in both localized and extended systems. Furthermore, this family has been designed to be evaluated by a single integration in momentum space when a constant reference density is used. The atomic total kinetic energies are in good agreement with the exact calculations. The kinetic-energy density corresponding to each functional has been assessed to control its quality. The results show that, in general, these functionals behave better than both the Thomas-Fermi and all semilocal generalized gradient approximation functionals when describing the kinetic-energy density of atoms, providing a better description of the nonlocal effects of the kinetic energy of electron systems
International Nuclear Information System (INIS)
Advances in instrumentation regarding 3rd generation synchrotron light sources and electron spectrometers has enabled the field of high kinetic energy photoelectron spectroscopy (HIKE) (also often denoted hard X-ray photoelectron spectroscopy (HX-PES or HAXPES)). Over the last years, the amount of investigations that relies on the HIKE method has increased dramatically and can arguably be said to have given a rebirth of the interest in photoelectron spectroscopy in many areas. It is in particular the much increased mean free path at higher kinetic energies in combination with the elemental selectivity of the core level spectroscopies in general that has lead to this fact, as it makes it possible to investigate the electronic structure of materials with a substantially reduced surface sensitivity. In this review we demonstrate how HIKE can be used to investigate the interface properties in multilayer systems. Relative intensities of the core level photoelectron peaks and their chemical shifts derived from binding energy changes are found to give precise information on physico-chemical properties and quality of the buried layers. Interface roughening, including kinetic properties such as the rate of alloying, and temperature effects on the processes can be analyzed quantitatively. We will also provide an outline of the theoretical framework that is used to support the interpretation of data. We provide examples from our own investigations of multilayer systems which comprises both systems of more model character and a multilayer system very close to real applications in devices that are considered to be viable alternative to the present read head technology. The experimental data presented in this review is exclusively recorded at the BESSY-II synchrotron at the Helmholtz-Zentrum Berlin fuer Materialien und Energie. This HIKE facility is placed at the bending magnet beamline KMC-1, which makes it different from several other facilities which relies on undulators as
Energy Technology Data Exchange (ETDEWEB)
Granroth, Sari [Department of Physics and Astronomy, University of Turku, FIN-20014 Turku (Finland); Department of Physics and Materials Science, Uppsala University, SE-751 21 Uppsala (Sweden); Olovsson, Weine [Department of Materials Science and Engineering, Kyoto University, Sakyo, Kyoto 606-8501 (Japan); Holmstroem, Erik [Instituto de Fisica, Universidad Austral de Chile, Valdivia (Chile); Knut, Ronny [Department of Physics and Materials Science, Uppsala University, SE-751 21 Uppsala (Sweden); Gorgoi, Mihaela [Helmholtz Zentrum Berlin, BESSY II, Albert-Einstein-Str. 15, 12489 Berlin (Germany); Svensson, Svante [Department of Physics and Materials Science, Uppsala University, SE-751 21 Uppsala (Sweden); Karis, Olof, E-mail: olof.karis@fysik.uu.s [Department of Physics and Materials Science, Uppsala University, SE-751 21 Uppsala (Sweden)
2011-01-15
Advances in instrumentation regarding 3rd generation synchrotron light sources and electron spectrometers has enabled the field of high kinetic energy photoelectron spectroscopy (HIKE) (also often denoted hard X-ray photoelectron spectroscopy (HX-PES or HAXPES)). Over the last years, the amount of investigations that relies on the HIKE method has increased dramatically and can arguably be said to have given a rebirth of the interest in photoelectron spectroscopy in many areas. It is in particular the much increased mean free path at higher kinetic energies in combination with the elemental selectivity of the core level spectroscopies in general that has lead to this fact, as it makes it possible to investigate the electronic structure of materials with a substantially reduced surface sensitivity. In this review we demonstrate how HIKE can be used to investigate the interface properties in multilayer systems. Relative intensities of the core level photoelectron peaks and their chemical shifts derived from binding energy changes are found to give precise information on physico-chemical properties and quality of the buried layers. Interface roughening, including kinetic properties such as the rate of alloying, and temperature effects on the processes can be analyzed quantitatively. We will also provide an outline of the theoretical framework that is used to support the interpretation of data. We provide examples from our own investigations of multilayer systems which comprises both systems of more model character and a multilayer system very close to real applications in devices that are considered to be viable alternative to the present read head technology. The experimental data presented in this review is exclusively recorded at the BESSY-II synchrotron at the Helmholtz-Zentrum Berlin fuer Materialien und Energie. This HIKE facility is placed at the bending magnet beamline KMC-1, which makes it different from several other facilities which relies on undulators as
A simplified model for average kinetic energy flux within large wind turbine arrays
Markfort, Corey; Zhang, Wei; Porte-Agel, Fernando
2015-11-01
We investigate the kinetic energy distribution within an array of wind turbines using a 1-D model for the interactions between large-scale wind farms and the atmospheric boundary layer (ABL). Obstructed shear flow scaling is used to predict the development length of the wind farm flow as well as vertical momentum flux. Within the region of flow development, momentum and energy is advected into the wind farm and wake turbulence draws excess momentum in from between turbines. This is characterized by large dispersive fluxes. Once the flow within the farm is developed, the area - averaged velocity profile exhibits an inflection point, characteristic of obstructed shear flows. The inflected velocity profile is responsible for a characteristic turbulence eddy scale, which may be responsible for a significant amount of the vertical momentum and energy flux. Prediction of this scale is useful for determining the amount of available power for harvesting. The model result for kinetic energy flux is compared to wind tunnel measurements. The model is useful for optimizing wind turbine spacing and layout, and for assessing the impacts of wind farms on nearby wind resources and the environment.
Enhanced von Weizsäcker Wang-Govind-Carter kinetic energy density functional for semiconductors
Shin, Ilgyou; Carter, Emily A.
2014-05-01
We propose a new form of orbital-free (OF) kinetic energy density functional (KEDF) for semiconductors that is based on the Wang-Govind-Carter (WGC99) nonlocal KEDF. We enhance within the latter the semi-local von Weizsäcker KEDF term, which is exact for a single orbital. The enhancement factor we introduce is related to the extent to which the electron density is localized. The accuracy of the new KEDF is benchmarked against Kohn-Sham density functional theory (KSDFT) by comparing predicted energy differences between phases, equilibrium volumes, and bulk moduli for various semiconductors, along with metal-insulator phase transition pressures. We also compare point defect and (100) surface energies in silicon for a broad test of its applicability. This new KEDF accurately reproduces the exact non-interacting kinetic energy of KSDFT with only one additional adjustable parameter beyond the three parameters in the WGC99 KEDF; it exhibits good transferability between semiconducting to metallic silicon phases and between various III-V semiconductors without parameter adjustment. Overall, this KEDF is more accurate than previously proposed OF KEDFs (e.g., the Huang-Carter (HC) KEDF) for semiconductors, while the computational efficiency remains at the level of the WGC99 KEDF (several hundred times faster than the HC KEDF). This accurate, fast, and transferable new KEDF holds considerable promise for large-scale OFDFT simulations of metallic through semiconducting materials.
Visualizing the large-$Z$ scaling of the kinetic energy density of atoms
Cancio, Antonio C
2016-01-01
The scaling of neutral atoms to large $Z$, combining periodicity with a gradual trend to homogeneity, is a fundamental probe of density functional theory, one that has driven recent advances in understanding both the kinetic and exchange-correlation energies. Although research focus is normally upon the scaling of energies, insights can also be gained from energy densities. We visualize the scaling of the positive-definite kinetic energy density (KED) in closed-shell atoms, in comparison to invariant quantities based upon the gradient and Laplacian of the density. We notice a striking fit of the KED within the core of any atom to a gradient expansion using both the gradient and the Laplacian, appearing as an asymptotic limit around which the KED oscillates. The gradient expansion is qualitatively different from that derived from first principles for a slowly-varying electron gas and is correlated with a nonzero Pauli contribution to the KED near the nucleus. We propose and explore orbital-free meta-GGA models...
Systematics of Kinetic Freeze-out Properties in High Energy Collisions from STAR
,
2014-01-01
The main aim of the RHIC Beam Energy Scan (BES) program is to explore the QCD phase diagram which includes search for a possible QCD critical point and the phase boundary between QGP and hadronic phase. We report the collision energy and centrality dependence of kinetic freeze-out properties from the measured mid-rapidity ($|y|<0.1)$ light hadrons (pions, kaons, protons and their anti-particles) for Au+Au collisions at the center-of-mass energy $\\sqrt{s_{NN}} =$ 7.7, 11.5, 19.6, 27, and 39 GeV. The STAR detector, with a large uniform acceptance and excellent particle identification is used in the data collection and analysis. The kinetic freeze-out temperature $T_{\\rm{kin}}$ and average collective velocity $\\langle \\beta \\rangle$ parameters are extracted from blast-wave fits to the identified hadron spectra and systematically compared with the results from other collision energies including those at AGS, SPS and LHC. It is found that all results fall into an anti-correlation band in the 2-dimension ($T_{\\r...
International Nuclear Information System (INIS)
Using the point-splitting procedure and the method of functional integration, we define currents in the chiral Schwinger model and compute the correlation funtions of currents with themselves and with the fundamental fields. We show that the ambiguities in the choice of the phase factor employed in the point-splitting procedure can be compensated by mixing of the currents with the gauge potential Aμ and εμνAν. A three-parameter family of conserved currents is found and the transformations they generate are identified. In order to construct the conserved energy-momentum tensor, it is necessary to allow for mixings with AμAν and gμνAαAα. We compute the two-point function of the energy-momentum tensor and the correlation functions of it with the fundamental fields. The physics of the chiral model is discussed in comparison with the vector model
An Unbroken Axial Vector Current Conservation Law
Sharafiddinov, Rasulkhozha S
2015-01-01
The mass, energy and momentum of the neutrino of a true flavor have an axial-vector nature. As a consequence, the left-handed truly neutral neutrino in an axial-vector field of emission can be converted into a right-handed one and vice versa. This predicts the unidenticality of masses, energies and momenta of neutrinos of the different components. Recognizing such a difference in masses, energies, momenta and accepting that the left-handed axial-vector neutrino and the right-handed antineutrino of true neutrality refer to long-lived C-odd leptons, and the right-handed truly neutral neutrino and the left-handed axial-vector antineutrino are of short-lived fermions of C-oddity, we would write a new CP-even Dirac equation taking into account the flavor symmetrical axial-vector mass, energy and momentum matrices. Their presence explains the spontaneous mirror symmetry violation, confirming that an axial-vector current conservation law has never violated. They reflect the availability of a mirror Minkowski space i...
Belgacem, O; Pittenauer, E; Openshaw, M E; Hart, P J; Bowdler, A; Allmaier, G
2016-01-01
Rationale For the last two decades, curved field reflectron technology has been used in matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometers, assisting in the generation of post-source-decay (PSD) or collision-induced dissociation (CID) without decelerating precursor ions, producing true high-energy CID spectra. The result was the generation of product ion mass spectra with product ions typical of high-energy (10 keV and beyond) collision processes. The disadvantage of this approach was the lack of resolution in CID spectra resulting from the excess laser energy deposition used to generate those MS/MS spectra. The work presented in this study overcomes this limitation and includes comprehensive examples of high-energy and high-resolution CID MALDI-MS/MS spectra of biomolecules. Methods The devices used in this study are TOF/RTOF instruments equipped with a high-vacuum MALDI ion source. High-resolution and high-energy CID spectra result from the use of axial spatial distribution focusing (ASDF) in combination with curved field reflectron technology. Results A CID spectrum of the P14R1 peptide exhibits product ion resolution in excess of 10,000 (FWHM) but at the same time yields typical high-energy product ions such as w- and [y–2]-type ion series. High-energy CID spectra of lipids, exemplified by a glycerophospholipid and triglyceride, demonstrate C–C backbone fragmentation elucidating the presence of a hydroxyl group in addition to double-bond positioning. A complex high mannose carbohydrate (Man)8(GlcNAc)2 was also studied at 20 keV collision energy and revealed further high-energy product ions with very high resolution, allowing unambiguous detection and characterization of cross-ring cleavage-related ions. Conclusions This is the first comprehensive study using a MALDI-TOF/RTOF instrument equipped with a curved field reflectron and an ASDF device prior to the reflectron. © 2015 The Authors. Rapid Communications in
Energy Technology Data Exchange (ETDEWEB)
Juarez, A M; Hoyos-Campo, L M [Institute de Ciencias Fisicas, Universidad Nacional Autonoma de Mexico, Cuernavaca, Mor. 62210 (Mexico); Redt, E; Hoenert, M; Aguilar, A [Lawrence Berkeley National Laboratory, Berkeley CA-94720 (United States); Rolles, D [Max Planck Advanced Study Group, CFEL, D-22761 Hamburg (Germany); Berrah, N, E-mail: aaguilar@lbl.go [Department of Physics, Western Michigan University, Kalamazoo MI-49008 (United States)
2009-11-01
We present photoelectron angular distributions (PADs) in Helium and Neon for electrons with excess energies between 5 and 100 meV. These ultra-low kinetic energy PAD measurements were obtained with a modified Velocity Map Imaging spectrometer (VMI) and VUV light from the Advanced Light Source (ALS) synchrotron radiation source. The efficiency and reliability of the spectrometer at this ultra-low kinetic energy range has been tested by determining the variation with energy of the asymmetry, {beta}, parameter of photoelectrons from the s-shell direct ionization in Helium. For Neon, we determined the energy dependent asymmetry parameters across the 's' and 'd' autoionizing resonances between the P{sub 3/2} and P{sub 1/2} ionic states. Furthermore, we measured the asymmetry parameter for photoelectrons produced from the n = 2 to n = 6 satellite states of He. These measurements were performed at values of excess kinetic energy previously unexplored.
International Nuclear Information System (INIS)
We present photoelectron angular distributions (PADs) in Helium and Neon for electrons with excess energies between 5 and 100 meV. These ultra-low kinetic energy PAD measurements were obtained with a modified Velocity Map Imaging spectrometer (VMI) and VUV light from the Advanced Light Source (ALS) synchrotron radiation source. The efficiency and reliability of the spectrometer at this ultra-low kinetic energy range has been tested by determining the variation with energy of the asymmetry, β, parameter of photoelectrons from the s-shell direct ionization in Helium. For Neon, we determined the energy dependent asymmetry parameters across the 's' and 'd' autoionizing resonances between the P3/2 and P1/2 ionic states. Furthermore, we measured the asymmetry parameter for photoelectrons produced from the n = 2 to n = 6 satellite states of He. These measurements were performed at values of excess kinetic energy previously unexplored.
Surface nanoscale axial photonics
Sumetsky, M.; Fini, J. M.
2011-01-01
Dense photonic integration promises to revolutionize optical computing and communications. However, efforts towards this goal face unacceptable attenuation of light caused by surface roughness in microscopic devices. Here we address this problem by introducing Surface Nanoscale Axial Photonics (SNAP). The SNAP platform is based on whispering gallery modes circulating around the optical fiber surface and undergoing slow axial propagation readily described by the one-dimensional Schr\\"odinger e...
Graph-based analysis of kinetics on multidimensional potential-energy surfaces
Okushima, T.; Niiyama, T.; Ikeda, K. S.; Shimizu, Y.
2009-09-01
The aim of this paper is twofold: one is to give a detailed description of an alternative graph-based analysis method, which we call saddle connectivity graph, for analyzing the global topography and the dynamical properties of many-dimensional potential-energy landscapes and the other is to give examples of applications of this method in the analysis of the kinetics of realistic systems. A Dijkstra-type shortest path algorithm is proposed to extract dynamically dominant transition pathways by kinetically defining transition costs. The applicability of this approach is first confirmed by an illustrative example of a low-dimensional random potential. We then show that a coarse-graining procedure tailored for saddle connectivity graphs can be used to obtain the kinetic properties of 13- and 38-atom Lennard-Jones clusters. The coarse-graining method not only reduces the complexity of the graphs, but also, with iterative use, reveals a self-similar hierarchical structure in these clusters. We also propose that the self-similarity is common to many-atom Lennard-Jones clusters.
Axial Vircator for Electronic Warfare Applications
L. Drazan; R. Vrana
2009-01-01
This paper deals with a high power microwave generator with virtual cathode – vircator in axial release for electronic warfare applications. The classification of directed energy weapons microwave (DEWM) is introduced together with basic block diagrams of a particular class of DEWM. In the paper, methods for designing vircator pulsed power supply, axial vircator structure, measurement methods and experimental results are presented. The vircator in electromagnetic ammunition is powered b...
Nonperturbative Aspects of Axial Vector Vertex
Institute of Scientific and Technical Information of China (English)
ZONG Hong-Shi; CHEN Xiang-Song; WANG Fan; CHANG Chao-Hsi; ZHAO En-Guang
2002-01-01
It is shown how the axial vector current of current quarks is related to that of constituent quarks within the framework of the global color symmetry model.Gluon dressing of the axial vector vertex and the quark self-energy functions are described by the inhomogeneous Bethe-Salpeter equation in the ladder approximation and the Schwinger Dyson equation in the rainbow approximation,respectively.
Sensory Agreement Guides Kinetic Energy Optimization of Arm Movements during Object Manipulation.
Farshchiansadegh, Ali; Melendez-Calderon, Alejandro; Ranganathan, Rajiv; Murphey, Todd D; Mussa-Ivaldi, Ferdinando A
2016-04-01
The laws of physics establish the energetic efficiency of our movements. In some cases, like locomotion, the mechanics of the body dominate in determining the energetically optimal course of action. In other tasks, such as manipulation, energetic costs depend critically upon the variable properties of objects in the environment. Can the brain identify and follow energy-optimal motions when these motions require moving along unfamiliar trajectories? What feedback information is required for such optimal behavior to occur? To answer these questions, we asked participants to move their dominant hand between different positions while holding a virtual mechanical system with complex dynamics (a planar double pendulum). In this task, trajectories of minimum kinetic energy were along curvilinear paths. Our findings demonstrate that participants were capable of finding the energy-optimal paths, but only when provided with veridical visual and haptic information pertaining to the object, lacking which the trajectories were executed along rectilinear paths. PMID:27035587
Potential to kinetic energy conversion in wave number domain for the Southern Hemisphere
Huang, H.-J.; Vincent, D. G.
1984-01-01
Preliminary results of a wave number study conducted for the South Pacific Convergence Zone (SPCZ) using FGGE data for the period January 10-27, 1979 are reported. In particular, three variables (geomagnetic height, z, vertical p-velocity, omega, and temperature, T) and one energy conversion quantity, omega-alpha (where alpha is the specific volume), are shown. It is demonstrated that wave number 4 plays an important role in the conversion from available potential energy to kinetic energy in the Southern Hemisphere tropics, particularly in the vicinity of the SPCZ. It is therefore suggested that the development and movement of wave number 4 waves be carefully monitored in making forecasts for the South Pacific region.
Sensory Agreement Guides Kinetic Energy Optimization of Arm Movements during Object Manipulation
Farshchiansadegh, Ali; Melendez-Calderon, Alejandro; Ranganathan, Rajiv; Murphey, Todd D.; Mussa-Ivaldi, Ferdinando A.
2016-01-01
The laws of physics establish the energetic efficiency of our movements. In some cases, like locomotion, the mechanics of the body dominate in determining the energetically optimal course of action. In other tasks, such as manipulation, energetic costs depend critically upon the variable properties of objects in the environment. Can the brain identify and follow energy-optimal motions when these motions require moving along unfamiliar trajectories? What feedback information is required for such optimal behavior to occur? To answer these questions, we asked participants to move their dominant hand between different positions while holding a virtual mechanical system with complex dynamics (a planar double pendulum). In this task, trajectories of minimum kinetic energy were along curvilinear paths. Our findings demonstrate that participants were capable of finding the energy-optimal paths, but only when provided with veridical visual and haptic information pertaining to the object, lacking which the trajectories were executed along rectilinear paths. PMID:27035587
International Nuclear Information System (INIS)
We present a model which allows for the calculation of fragment excitation energy, fragment kinetic energies and neutron evaporation in nuclear fission. The model is based on the assumption that, at the end of the fission process, fragments are excited to a temperature which is proportional to the reaction Q-value. Starting from this assumption the distribution functions of fragment excitation can be formulated and the distribution functions for the kinetic energies can be derived by a Monte Carlo method. From the distribution functions for the excitation energy neutron evaporation characteristics are calculated. (author)
Visualizing the Kohn-Sham kinetic energy density and its orbital-free description in molecules
Cancio, Antonio C; Kuna, Aeryk I
2015-01-01
We visualize the Kohn-Sham kinetic energy density (KED), and the ingredients -- the electron density, its gradient and Laplacian -- used to construct orbital-free models of it, for the AE6 test set of molecules. These are compared to related quantities used in metaGGA's, to characterize two important limits -- the gradient expansion and the localized-electron limit typified by the covalent bond. We find the second-order gradient expansion of the KED to be a surprisingly successful predictor of the exact KED, particularly at low densities where this approximation fails for exchange. This contradicts the conjointness conjecture that the optimal enhancement factors for orbital-free kinetic and exchange energy functionals are identical. In addition we find significant problems with a recent metaGGA-level orbital-free KED, especially for regions of strong electron localization. We define an orbital-free description of electron localization and a revised metaGGA that improves upon atomization energies significantly...
Kinetic energies of cluster fragments in ternary fission of 252 Cf
Vijayaraghavan, K. R.; von Oertzen, W.; Balasubramaniam, M.
2012-03-01
The kinetic energy distribution and potential energies of fragments from the collinear cluster tripartition (CCT), the "true" ternary fission of 252Cf, have been calculated. It is assumed that the breakup of the nucleus into three fragments happens sequentially in two steps from a hyper-deformed shape. In the first step a first neck rupture occurs of the parent radioactive nucleus, forming two fragments (one of them is usually 132Sn) and, in the second step, one of the two fragments breaks into two other fragments, resulting finally in three fragments (the experiment is based on a binary coincidence where a missing mass is determined). We show the result for the principal combination of the three spherical fragments (semi-magic isotopes of Sn, Ca, Ni) observed recently experimentally. These isotopes are clusters with high Q -values, which produce the highest yields in the ternary fission bump. It is shown that the kinetic energies of the middle fragments have very low values, making their experimental detection quite difficult. This fact explains why the direct detection of true ternary fission with three fragments heavier than A > 40 has escaped experimental observation.
Andrade, Tomás; Kelly, William R.; Marolf, Donald
2015-10-01
The gravitational Dirichlet problem—in which the induced metric is fixed on boundaries at finite distance from the bulk—is related to simple notions of UV cutoffs in gauge/gravity duality and appears in discussions relating the low-energy behavior of gravity to fluid dynamics. We study the Einstein-Maxwell version of this problem, in which the induced Maxwell potential on the wall is also fixed. For flat walls in otherwise asymptotically flat spacetimes, we identify a moduli space of Majumdar-Papapetrou-like static solutions parametrized by the location of an extreme black hole relative to the wall. Such solutions may be described as balancing gravitational repulsion from a negative-mass image source against electrostatic attraction to an oppositely signed image charge. Standard techniques for handling divergences yield a moduli space metric with an eigenvalue that becomes negative near the wall, indicating a region of negative kinetic energy and suggesting that the Hamiltonian may be unbounded below. One may also surround the black hole with an additional (roughly spherical) Dirichlet wall to impose a regulator whose physics is more clear. Negative kinetic energies remain, though new terms do appear in the moduli space metric. The regulator dependence indicates that the adiabatic approximation may be ill-defined for classical extreme black holes with Dirichlet walls.
Estimates of turbulent kinetic energy dissipation rate for a stratified flow in a wind tunnel
Puhales, Franciano Scremin; Demarco, Giuliano; Martins, Luis Gustavo Nogueira; Acevedo, Otávio Costa; Degrazia, Gervásio Annes; Welter, Guilherme Sausen; Costa, Felipe Denardin; Fisch, Gilberto Fernando; Avelar, Ana Cristina
2015-08-01
In this work a method to estimate turbulent kinetic energy dissipation rate (TKEDR) was presented. The technique uses the second-order structure function and Kolmogorov's law for inertial subrange. This methodology was applied on both neutral and stable stratification wind tunnel data, where the frozen turbulence hypothesis was assumed. The experiments were made with Reynolds Number ranging from 103 up to 104. The results show difference between the neutral and stable cases, but this gap decreases with the mean wind speed. Furthermore, TKEDR evaluated was used to describe the inertial subrange in the longitudinal velocity spectrum with a good agreement with the experimental data.
Half-lives and kinetic energies for the spontaneously emitted heavy clusters from nuclei
International Nuclear Information System (INIS)
The partial half-lives, branching ratios relative to the alpha decay, kinetic energies and Q-values for the most probable spontaneously emitted heavy ions from 766 nuclides with z=47-106 and total half-lives longer than 1 μs, are estimated by using the analytical supersymmetric fission model, a semiempirical formula for α-decay life-times which are not measured, and the Wapstra-Audi new mass tables. Even the so-called 'stable' nuclides with Z>40 are meta-stable relative to the new decay modes. The experimental evidences are briefly reviewed. (orig.)
Observed and Simulated Power Spectra of Kinetic and Magnetic Energy retrieved with 2D inversions
Danilovic, S; van Noort, M; Cameron, R
2016-01-01
We try to retrieve the power spectra with certainty to the highest spatial frequencies allowed by current instrumentation. For this, we use 2D inversion code that were able to recover information up to the instrumental diffraction limit. The retrieved power spectra have shallow slopes extending further down to much smaller scales than found before. They seem not to show any power law. The observed slopes at subgranular scales agree with those obtained from recent local dynamo simulations. Small differences are found for vertical component of kinetic energy that suggest that observations suffer from an instrumental effect that is not taken into account.
Kinetic energy releases of small amino acids upon interaction with keV ions
International Nuclear Information System (INIS)
In chromatin, DNA is tightly packed into one complex together with histone and non-histone proteins. These proteins are known to protect the DNA against indirect and to some extent even direct radiation damage. Radiation action upon amino acids is thus one of the primary steps in biological radiation action. In this paper we investigate the ionization and fragmentation of the gas-phase amino acids glycine, alanine and valine upon interaction with keV α-particles. High resolution coincidence time-of-flight mass spectrometry is used to determine the dominant fragmentation channels as well as fragment kinetic energies. (authors)
Kinetic energy releases of small amino acids upon interaction with keV ions
Energy Technology Data Exchange (ETDEWEB)
Bari, S.; Alvarado, F.; Postma, J.; Sobocinski, P.; Hoekstra, R.; Schlatholter, T. [Groningen Univ., KVI Atomic Physics (Netherlands); Schlatholter, T. [Universites P. et M. Curie and D. Diderot, INSP, CNRS UMR 75-88, 75 - Paris (France)
2009-01-15
In chromatin, DNA is tightly packed into one complex together with histone and non-histone proteins. These proteins are known to protect the DNA against indirect and to some extent even direct radiation damage. Radiation action upon amino acids is thus one of the primary steps in biological radiation action. In this paper we investigate the ionization and fragmentation of the gas-phase amino acids glycine, alanine and valine upon interaction with keV {alpha}-particles. High resolution coincidence time-of-flight mass spectrometry is used to determine the dominant fragmentation channels as well as fragment kinetic energies. (authors)
Releasable Kinetic Energy-Based Inertial Control of a DFIG Wind Power Plant
DEFF Research Database (Denmark)
Lee, Jinsik; Muljadi, Eduard; Sørensen, Poul Ejnar; Kang, Yong Cheol
2016-01-01
Wind turbine generators (WTGs) in a wind power plant (WPP) contain different levels of releasable kinetic energy (KE) because of the wake effects. This paper proposes a releasable KE-based inertial control scheme for a doubly fed induction generator (DFIG) WPP that differentiates the contributions...... loops. The proposed scheme adjusts the two loop gains in a DFIG controller depending on its rotor speed so that a DFIG operating at a higher rotor speed releases more KE. The performance of the proposed scheme was investigated under various wind conditions. The results clearly indicate that the proposed...
International Nuclear Information System (INIS)
Several compact proton accelerator systems for use in proton therapy have recently been proposed. Of paramount importance to the development of such an accelerator system is the maximum kinetic energy of protons, immediately prior to entry into the patient, that must be reached by the treatment system. The commonly used value for the maximum kinetic energy required for a medical proton accelerator is 250 MeV, but it has not been demonstrated that this energy is indeed necessary to treat all or most patients eligible for proton therapy. This article quantifies the maximum kinetic energy of protons, immediately prior to entry into the patient, necessary to treat a given percentage of patients with rotational proton therapy, and examines the impact of this energy threshold on the cost and feasibility of a compact, gantry-mounted proton accelerator treatment system. One hundred randomized treatment plans from patients treated with IMRT were analyzed. The maximum radiological pathlength from the surface of the patient to the distal edge of the treatment volume was obtained for 180 deg. continuous arc proton therapy and for 180 deg. split arc proton therapy (two 90 degree sign arcs) using CT profiles from the Pinnacle (Philips Medical Systems, Madison, WI) treatment planning system. In each case, the maximum kinetic energy of protons, immediately prior to entry into the patient, that would be necessary to treat the patient was calculated using proton range tables for various media. In addition, Monte Carlo simulations were performed to quantify neutron production in a water phantom representing a patient as a function of the maximum proton kinetic energy achievable by a proton treatment system. Protons with a kinetic energy of 240 MeV, immediately prior to entry into the patient, were needed to treat 100% of patients in this study. However, it was shown that 90% of patients could be treated at 198 MeV, and 95% of patients could be treated at 207 MeV. Decreasing the
Sabry, Hanan
2014-05-01
Solar screens are typically used to control solar access into building spaces. They proved their usefulness in improving the daylighting and energy performance of buildings in the hot arid desert environments which are endowed with abundance of clear skies.The daylighting and energy performance of solar screens is affected by many parameters. These include screen perforation, depth, reflectivity and color, aspect ratio of openings, shape, tilt angle and rotation. Changing some of these parameters can improve the daylighting performance drastically. However, this can result in increased energy consumption. A balanced solution must be sought, where acceptable daylighting performance would be achieved at minimum energy consumption.This paper aims at defining solar screen designs that achieve visual comfort and at the same time minimum energy consumption in residential desert settings. The study focused on the effect of changing the solar screen axial rotation and the aspect ratio of its openings under the desert clear-sky. The individual and combined effects of changing these parameters were studied.Results of this study demonstrated that a non-rotated solar screen that has wide horizontal openings (aspect ratio of 18:1) proved to be successful in the north and south orientations. Its performance in the east/west orientations was also superior. In contrast, the screen that was rotated along its vertical axis while having small size openings (aspect ratio of 1:1) proved to be more successful in the east/west orientations. Its performance in the north orientation was also good. These solutions enhanced daylighting performance, while maintaining the energy consumption at a minimum.Moreover, it was observed that combining two screen parameters which proved useful in previous studies on daylighting or thermal performance does not add up to better solutions. The combined solutions that were tested in this study did not prove successful in satisfying daylighting and thermal
Electronic coherence and the kinetics of inter-complex energy transfer in light-harvesting systems.
Huo, Pengfei; Miller, Thomas F
2015-12-14
We apply real-time path-integral dynamics simulations to characterize the role of electronic coherence in inter-complex excitation energy transfer (EET) processes. The analysis is performed using a system-bath model that exhibits the essential features of light-harvesting networks, including strong intra-complex electronic coupling and weak inter-complex coupling. Strong intra-complex coupling is known to generate both static and dynamic electron coherences, which delocalize the exciton over multiple chromophores and potentially influence the inter-complex EET dynamics. With numerical results from partial linearized density matrix (PLDM) real-time path-integral calculations, it is found that both static and dynamic coherence are correlated with the rate of inter-complex EET. To distinguish the impact of these two types of intra-complex coherence on the rate of inter-complex EET, we use Multi-Chromophore Förster Resonance Energy Transfer (MC-FRET) theory to map the original parameterization of the system-bath model to an alternative parameterization for which the effects of static coherence are preserved while the effects of dynamic coherence are largely eliminated. It is then shown that both parameterizations of the model (i.e., the original that supports dynamic coherence and the alternative that eliminates it), exhibit nearly identical EET kinetics and population dynamics over a wide range of parameters. These observations are found to hold for cases in which either the EET donor or acceptor is a dimeric complex and for cases in which the dimeric complex is either symmetric or asymmetric. The results from this study suggest that dynamic coherence plays only a minor role in the actual kinetics of inter-complex EET, whereas static coherence largely governs the kinetics of incoherent inter-complex EET in light-harvesting networks. PMID:26073739
Liu, Guanlin; Leng, Qiang; Lian, Jiawei; Guo, Hengyu; Yi, Xi; Hu, Chenguo
2015-01-21
Great attention has been paid to nanogenerators that harvest energy from ambient environments lately. In order to give considerable output current, most nanogenerators require high-velocity motion that in most cases can hardly be provided in our daily life. Here we report a notepad-like triboelectric generator (NTEG), which uses simple notepad-like structure to generate elastic deformation so as to turn a low-velocity kinetic energy into high-velocity kinetic energy through the conversion of elastic potential energy. Therefore, the NTEG can achieve high current output under low-velocity motion, which completely distinguishes it from tribogenerators previously reported. The factors that may affect the output performance are explored, including the number of slices, active length of slice, press speed, and vertical displacement. In addition, the working mechanism is systematically studied, indicating that the efficiency of the generator can be greatly enhanced by interconversion between kinetic energy and elastic potential energy. The short-circuit current, the open-circuit voltage, and power density are 205 μA and 470 V and 9.86 W/m(2), respectively, which is powerful enough to light up hundreds of light-emitting diodes (LEDs) and charge a commercial capacitor. Besides, NTEGs have been successfully applied to a self-powered door monitor. PMID:25564956
An ocean kinetic energy converter for low-power applications using piezoelectric disk elements
Viñolo, C.; Toma, D.; Mànuel, A.; del Rio, J.
2013-09-01
The main problem facing long-term electronic system deployments in the sea, is to find a feasible way to supply them with the power they require. Harvesting mechanical energy from the ocean wave oscillations and converting it into electrical energy, provides an alternative method for creating self-contained power sources. However, the very low and varying frequency of ocean waves, which generally varies from 0.1 Hz to 2 Hz, presents a hurdle which has to be overcome if this mechanical energy is to be harvested. In this paper, a new sea wave kinetic energy converter is described using low-cost disk piezoelectric elements, which has no dependence on their excitement frequency, to feed low-consumption maritime-deployed electronic devices. The operating principles of the piezoelectric device technique are presented, including analytical formulations describing the transfer of energy. Finally, a prototypical design, which generates electrical energy from the motion of a buoy, is introduced. The paper concludes with the the behavior study of the piezoelectric prototype device as a power generator.
Hypovalency--a kinetic-energy density description of a 4c-2e bond.
Jacobsen, Heiko
2009-06-01
A bond descriptor based on the kinetic energy density, the localized-orbital locator (LOL), is used to characterize the nature of the chemical bond in electron deficient multi-center bonds. The boranes B(2)H(6), B(4)H(4), B(4)H(10), [B(6)H(6)](2-), and [B(6)H(7)](-) serve as prototypical examples of hypovalent 3c-2e and 4c-2e bonding. The kinetic energy density is derived from a set of Kohn-Sham orbitals obtained from pure density functional calculations (PBE/TZVP), and the topology of LOL is analyzed in terms of (3,-3) attractors (Gamma). The B-B-B and B-H-B 3c-2e, and the B-B-H-B 4c-2e bonding situations are defined by their own characteristic LOL profiles. The presence of one attractor in relation to the three or four atoms that are engaged in electron deficient bonding provides sufficient indication of the type of 3c-2e or 4c-2e bond present. For the 4c-2e bond in [B(6)H(7)](-) the LOL analysis is compared to results from an experimental QTAIM study. PMID:19452076
Kinetic energy entrainment in wind turbine and actuator disc wakes: an experimental analysis
International Nuclear Information System (INIS)
The present experimental study focuses on the comparison between the wake of a two-bladed wind turbine and the one of an actuator disk. The flow field at the middle plane of the wake is measured with a stereoscopic particle image velocimetry setup, in the low-speed Open Jet Facility wind tunnel of the Delft University of Technology. The wind turbine wake is characterized by the complex dynamics of the tip vortex development and breakdown. Analysis of the flow statistics show anisotropic turbulent fluctuations in the turbine wake, with stronger components in the radial direction. The wake of the actuator disc is instead characterized by isotropic random fluctuations. The mixing process in the shear layer is further analysed in terms of flux of mean flow kinetic energy, to show the main differences between the kinetic energy entrainment in the actuator and the turbine wake. This project is intended to provide the basis for understanding the origin of the limitations of the current wake models based on the actuator disc assumption
Kinetic analysis and energy efficiency of phenol degradation in a plasma-photocatalysis system
International Nuclear Information System (INIS)
Combination of two kinds of advanced oxidation processes (AOPs) is an effective approach to control wastewater pollution. In this research, a pulsed discharge plasma system with multi-point-to-plate electrode and an immobilized TiO2 photocatalysis system is coupled to oxidize target pollutant in aqueous solution. Kinetic analysis (pseudo-first order kinetic constant, k) and energy efficiency (energy yield value at 50% phenol conversion, G50) of phenol oxidation in different reaction systems (plasma alone and plasma-photocatalysis) are reviewed to account for the synergistic mechanism of plasma and photocatalysis. The experimental results show that higher k and G50 of phenol oxidation can be obtained in the plasma-photocatalysis system under the conditions of different gas bubbling varieties, initial solution pH and radical scavenger addition. Moreover, the investigation tested hydroxyl radical (·OH) is the most important species for phenol removal in the synergistic system of plasma-photocatalysis as well as in the plasma alone system.
On the evaluation of the non-interacting kinetic energy in density functional theory.
Peach, Michael J G; Griffiths, David G J; Tozer, David J
2012-04-14
The utility of both an orbital-free and a single-orbital expression for computing the non-interacting kinetic energy in density functional theory is investigated for simple atomic systems. The accuracy of both expressions is governed by the extent to which the Kohn-Sham equation is solved for the given exchange-correlation functional and so special attention is paid to the influence of finite Gaussian basis sets. The orbital-free expression is a statement of the virial theorem and its accuracy is quantified. The accuracy of the single-orbital expression is sensitive to the choice of Kohn-Sham orbital. The use of particularly compact orbitals is problematic because the failure to solve the Kohn-Sham equation exactly in regions where the orbital has decayed to near-zero leads to unphysical behaviour in regions that contribute to the kinetic energy, rendering it inaccurate. This problem is particularly severe for core orbitals, which would otherwise appear attractive due to their formally nodeless nature. The most accurate results from the single-orbital expression are obtained using the relatively diffuse, highest occupied orbitals, although special care is required at orbital nodes. PMID:22502495
Jacob, Christoph R.; Beyhan, S. Maya; Visscher, Lucas
2007-06-01
We have investigated the functional derivative of the nonadditive kinetic-energy bifunctional, which appears in the embedding potential that is used in the frozen-density embedding formalism, in the limit that the separation of the subsystems is large. We have derived an exact expression for this kinetic-energy component of the embedding potential and have applied this expression to deduce its exact form in this limit. Comparing to the approximations currently in use, we find that while these approximations are correct at the nonfrozen subsystem, they fail completely at the frozen subsystem. Using test calculations on two model systems, a H2O⋯Li+ complex and a cluster of aminocoumarin C151 surrounded by 30 water molecules, we show that this failure leads to a wrong description of unoccupied orbitals, which can lead to convergence problems caused by too low-lying unoccupied orbitals and which can further have serious consequences for the calculation of response properties. Based on our results, a simple correction is proposed, and we show that this correction is able to fix the observed problems for the model systems studied.
Unified dark energy and dust dark matter dual to quadratic purely kinetic K-essence
Guendelman, Eduardo; Nissimov, Emil; Pacheva, Svetlana
2016-02-01
We consider a modified gravity plus single scalar-field model, where the scalar Lagrangian couples symmetrically both to the standard Riemannian volume-form (spacetime integration measure density) given by the square root of the determinant of the Riemannian metric, as well as to another non-Riemannian volume-form in terms of an auxiliary maximal-rank antisymmetric tensor gauge field. As shown in a previous paper, the pertinent scalar-field dynamics provides an exact unified description of both dark energy via dynamical generation of a cosmological constant, and dark matter as a "dust" fluid with geodesic flow as a result of a hidden Noether symmetry. Here we extend the discussion by considering a non-trivial modification of the purely gravitational action in the form of f(R) = R - α R^2 generalized gravity. Upon deriving the corresponding "Einstein-frame" effective action of the latter modified gravity-scalar-field theory we find explicit duality (in the sense of weak versus strong coupling) between the original model of unified dynamical dark energy and dust fluid dark matter, on one hand, and a specific quadratic purely kinetic "k-essence" gravity-matter model with special dependence of its coupling constants on only two independent parameters, on the other hand. The canonical Hamiltonian treatment and Wheeler-DeWitt quantization of the dual purely kinetic "k-essence" gravity-matter model is also briefly discussed.
Hamidifar, H.; Omid, M. H.; Keshavarzi, A.
2016-06-01
In this paper, the effect of flow relative depth (ratio of the floodplain to the main channel flow depths) and vegetation density on the kinetic energy and momentum correction coefficients (termed as α and β, respectively) was described based on an experimental study. A series of experiments was run using rigid dowels with seven flow relative depths and four vegetation densities in an asymmetric compound channel. The local flow velocities were measured using an acoustic Doppler velocimeter (ADV). Using regression analysis, velocity data were considered and equations were developed for calculating the kinetic energy and momentum correction coefficients as a function of the flow relative depth and vegetation density. The results show that the values of α and β decrease as the relative depth increases. Also, as the vegetation density increases, the effects of the vegetation on α and β increase too. Finally, by comparing with the findings of the previous researchers, it was found that the average values of the α for asymmetric compound channels with vegetation are 26.5% and 43.3% greater than those for asymmetric and symmetric compound channels without vegetation respectively while these values for β are 12.7% and 18.1%, respectively. Furthermore, the floodplain vegetation can increase the average values of coefficients α and β by 52.8% and 21.6%, respectively, in comparison with single channels.
The Effect of Kinetic Energy on the Reactions of Nucleogenic Carbon Atoms with Hydrocarbons
International Nuclear Information System (INIS)
The basic technique for studying the effect of kinetic energy on reactions of C atoms produced by nuclear transformation involves the well-known method of moderation with inert gases. However, this can be combined with other techniques such as (1) the use of scavengers to detect processes involving long- lived radicals, (2) degradative studies that serve to fix the position occupied by the labelled atom, (3) double tracer studies in which a reactant is partially labelled with deuterium and the isotopic composition of the labelled products is determined in order to establish the origin of the hydrogen which they contain. In this paper new results on product yields in two systems, neon-ethylene and neon-ethane, will be presented, and the relation of these results to other work involving degradative studies and double tracer experiments will be discussed. The discussion of the neon-ethylene results is in terms of the two previously postulated insertion mechanisms, insertion of the C atom into the C = C and into the C-H bonds to give C-C2H4 adducts, As neon concentration is increased no product is eliminated, but the relative yields of products are altered markedly. Those products such as acetylene and vinyl acetylene which can be formed from the initial C-C2H4 adducts via processes with a high energy requirement decrease in importance, and the yields of products formed in low energy processes, such as C5 compounds, increase. The ethane pattern is similar. Degradative studies have already shown that the intramolecular C11 distribution in allene and methyl- acetylene formed from ethylene is affected by neon moderation. These results imply both participation of the C = C and C-H bonds in formation of these products, and a dependence of the ratio of attack at the two bond types on the kinetic energy of the reacting C atom. Other work involving double tracer studies on acetylene formation from single molecules such as CH2CD2, CH3CH2D, CD9CDH2 and from various mixtures of
Elimination of the Translational Kinetic Energy Contamination in pre-Born-Oppenheimer Calculations
Simmen, Benjamin; Reiher, Markus
2012-01-01
In this paper we present a simple strategy for the elimination of the translational kinetic energy contamination of the total energy in pre-Born--Oppenheimer calculations carried out in laboratory-fixed Cartesian coordinates (LFCCs). The simple expressions for the coordinates and the operators are thus preserved throughout the calculations, while the mathematical form and the parametrisation of the basis functions are chosen so that the translational and rotational invariances are respected. The basis functions are constructed using explicitly correlated Gaussian functions (ECGs) and the global vector representation. First, we observe that it is not possible to parametrise the ECGs so that the system is at rest in LFCCs and at the same time the basis functions are square-integrable with a non-vanishing norm. Then, we work out a practical strategy to circumvent this problem by making use of the properties of the linear transformation between the LFCCs and translationally invariant and center-of-mass Cartesian ...
International Nuclear Information System (INIS)
In modelling the plasma kinetics in dielectric barrier discharges (DBDs), the electron energy conservation equation is often included in the rate equation analysis (rather than utilizing the local-field approximation) with the assumption that the electron energy distribution function (EEDF) has a Maxwellian profile. We show that adopting a Maxwellian EEDF leads to a serious overestimate of the calculated ionization/excitation rate coefficients and the electron mobility for typical plasma conditions in a xenon DBD. Alternative EEDF profiles are trialed (Druyvesteyn, bi-Maxwellian and bi-Druyvesteyn) and benchmarked against EEDFs obtained from solving the steady-state Boltzmann equation. A bi-Druyvesteyn EEDF is shown to be more inherently accurate for modelling simulations of xenon DBDs. (author)
Reiser, Georg; Habenicht, Wieland; Mueller-Dethlefs, Klaus
1993-06-01
Results are presented of nonresonant two-photon zero kinetic energy spectroscopy of ammonia, with resolution down to 0.4/cm. The spectra provide new rotational and vibrational data on the nu(2) vibrational progression of NH3(+). The adiabatic (field corrected) ionization energy is confirmed at 82,159 +/- 1 per cm.
Institute of Scientific and Technical Information of China (English)
Liu Yan-Hong; Zhang Jia-Liang; Ma Teng-Cai; Li Jian; Liu Dong-Ping
2007-01-01
The kinetic energy of ions in dielectric barrier discharge plasmas are analysed theoretically using the model of binary collisions between ions and gas molecules. Langevin equation for ions in other gases, Blanc law for ions in mixed gases, and the two-temperature model for ions at higher reduced field are used to determine the ion mobility. The kinetic energies of ions in CH4 + Ar(He) dielectric barrier discharge plasma at a fixed total gas pressure and various Ar (He)concentrations are calculated. It is found that with increasing Ar (He) concentration in CH4 + Ar (He) from 20% to 83%,the CH4+ kinetic energy increases from 69.6 (43.9) to 92.1 (128.5)eV, while the Ar+ (He+) kinetic energy decreases from 97 (145.2) to 78.8 (75.5)eV. The increase of CH4+ kinetic energy is responsible for the increase of hardness of diamond-like carbon films deposited by CH4 + Ar (He) dielectric barrier discharge without bias voltage over substrates.
NIST high throughput variable kinetic energy hard X-ray photoelectron spectroscopy facility
International Nuclear Information System (INIS)
Highlights: •High throughput HAPXES beamline provides beam energies between 2.1 and 6 keV. •Recent results in depth profiling of materials for next-generation CMOS. •Facility ideal or measurement of energy level alignment at buried interfaces. •Approved beamline NSLS II will provide wider energy range and X-ray flux. -- Abstract: We present an overview of the National Institute of Standards and Technology beamline X24A at the National Synchrotron Light Source at Brookhaven National Lab and recent work performed at the facility. The beamline is equipped for HAXPES measurements, with an energy range from 2.1 to 6 keV with Si(1 1 1) crystals. Recent measurements performed at the beamline include non-destructive depth dependent variable kinetic energy measurements of dielectric and semiconductor films and interfaces for microelectronics applications, band alignment at buried interfaces, and the electronic structure of bulk-like materials. The design and operation of the current beamline will be discussed, as well as the future NIST beamline at NSLS II
International Nuclear Information System (INIS)
An analysis based on the variation principle shows that in the molecules H2+, H2, B2, C2, N2, O2, F2, covalent bonding is driven by the attenuation of the kinetic energy that results from the delocalization of the electronic wave function. For molecular geometries around the equilibrium distance, two features of the wave function contribute to this delocalization: (i) Superposition of atomic orbitals extends the electronic wave function from one atom to two or more atoms; (ii) intra-atomic contraction of the atomic orbitals further increases the inter-atomic delocalization. The inter-atomic kinetic energy lowering that (perhaps counter-intuitively) is a consequence of the intra-atomic contractions drives these contractions (which per se would increase the energy). Since the contractions necessarily encompass both, the intra-atomic kinetic and potential energy changes (which add to a positive total), the fact that the intra-atomic potential energy change renders the total potential binding energy negative does not alter the fact that it is the kinetic delocalization energy that drives the bond formation
Indian Academy of Sciences (India)
J V Madhuri; V Malathi; S Satyanarayana
2004-03-01
Equilibrium constants are determined for the reaction of ethylester and methyl ester (aquo) cobaloximes with histamine, histidine, glycine and ethyl glycine ester as a function of pH at 25°C, using spectrophotometric technique. The functional dependence of p on the substitution rate of H2O varies with the p of the incoming ligand, establishing the existence of nucleophilic participation of the ligand in the transition state. This data is interpreted with the help of kinetic data where dissociation kinetic reactions were also studied as a function of pH. Binding and kinetic data were correlated based on the basicity, steric hindrance of the entering ligand and HSAB principle. To compare the rate constants of the entering ligands pH-independent second-order rate constants were calculated. The effect of incoming ligand on Co-C bond is studied using molecular mechanics.
International Nuclear Information System (INIS)
The mass and kinetic energy distribution of nuclear fragments from thermal neutron-induced fission of 235U(nth,f) have been studied using a Monte-Carlo simulation. Besides reproducing the pronounced broadening in the standard deviation of the kinetic energy at the final fragment mass number around m = 109, our simulation also produces a second broadening around m = 125. These results are in good agreement with the experimental data obtained by Belhafaf et al. and other results on yield of mass. We conclude that the obtained results are a consequence of the characteristics of the neutron emission, the sharp variation in the primary fragment kinetic energy and mass yield curves. We show that because neutron emission is hazardous to make any conclusion on primary quantities distribution of fragments from experimental results on final quantities distributions
International Nuclear Information System (INIS)
Neodymium plasma was produced between parallel electrodes by laser resonance photoionization. Ions were extracted and collected on a negative electrode by applying an electric field across the electrodes. Kinetic energy of ions collected at arbitrary time during ion collection was measured by the time-of-flight method using a gate electrode set behind negative electrode. It was confirmed that the kinetic energy of ions collected is equal to V0(eV) at any time during ion collection when electric potential V0(V) is applied between the parallel electrodes. This method will be used for measuring the kinetic energy of ions collected by improved methods such as by applying a electric potential to a wire electrode or by applying a radio frequency voltage. (author)
International Nuclear Information System (INIS)
In early 1977 the National Materials Advisory Board, an operating unit in the Commission on Sociotechnical Systems of the National Research Council, NAS/NAE, formed a study committee on High Density Materials for Kinetic Energy Penetrators. The Specific objectives of the Committee were defined as follows. Assess the potential of two materials for use in kinetic energy penetrators, including such factors as: (a) properties (as applied to this application: strength, toughness, and dynamic behavior); (b) uniformity, reliability and reproducibility; (c) deterioration in storage; (d) production capability; (e) ecological impact; (f) quality assurance; (g) availability, and (h) cost. The Committee was divided into two Panels; one panel devoted to the study of tungsten alloys and the other devoted to the study of depleted uranium alloys for use in Kinetic energy penetrators. This report represents the findings and recommendation of the Panel on Uranium
Andreani, Carla; Senesi, Roberto
2016-01-01
This study presents the first direct and quantitative measurements of the nuclear momentum distribution anisotropy and the quantum kinetic energy tensor in stable and metastable (supercooled) water near its triple point using Deep Inelastic Neutron Scattering (DINS). From the experimental spectra accurate lineshapes of the hydrogen momentum distributions are derived using an anisotropic Gaussian and a model independent framework. The experimental results, benchmarked with those obtained for the solid phase, provide the state of the art directional values of the hydrogen mean kinetic energy in metastable water. The determinations of the direction kinetic energies in the supercooled phase, benchmarked with ice at the same temperature, provide accurate and quantitative measurements of these dynamical observables in metastable and stable phases, {i.e.} key insight in the physical mechanisms of the hydrogen quantum state in both disordered and polycrystalline systems. The remarkable findings of this study establis...
International Nuclear Information System (INIS)
The rate constants for multiquantum vibration-to-vibration (V-V') energy exchanges in CO(v)-N2(v') collisions, with CO in highly excited vibrational levels v and N2 in the first few low-lying vibrational levels, were obtained from ab initio semiclassical calculations. A large temperature interval was explored, T = 100-500 K, while the vibrational quantum numbers v and v' were in the range v = (30-44) and v' = (0-3). The role played by these collisional processes in the vibrational kinetics of CO:Ar/He:N2 gas mixtures under typical laser conditions were explored in detail by using a recently developed kinetic modelling procedure. In particular, it was found that the V-V' exchanges between CO and N2 exert an essential influence on the time evolution of the vibrational population and on the associated small signal gain and spectral characteristics of the CO laser in both the fundamental and overtone bands
Kinetic model for the vibrational energy exchange in flowing molecular gas mixtures. Ph.D. Thesis
Offenhaeuser, F.
1987-01-01
The present study is concerned with the development of a computational model for the description of the vibrational energy exchange in flowing gas mixtures, taking into account a given number of energy levels for each vibrational degree of freedom. It is possible to select an arbitrary number of energy levels. The presented model uses values in the range from 10 to approximately 40. The distribution of energy with respect to these levels can differ from the equilibrium distribution. The kinetic model developed can be employed for arbitrary gaseous mixtures with an arbitrary number of vibrational degrees of freedom for each type of gas. The application of the model to CO2-H2ON2-O2-He mixtures is discussed. The obtained relations can be utilized in a study of the suitability of radiation-related transitional processes, involving the CO2 molecule, for laser applications. It is found that the computational results provided by the model agree very well with experimental data obtained for a CO2 laser. Possibilities for the activation of a 16-micron and 14-micron laser are considered.
Total kinetic energy release in the fast neutron-induced fission of $^{235}$U
Yanez, R; King, J; Barrett, J S; Fotiades, N; Lee, H Y
2015-01-01
We have measured the total kinetic energy (TKE) release for the $^{235}$U(n,f) reaction for $E_{n}$=2-100 MeV using the 2E method with an array of Si PIN diode detectors. The neutron energies were determined by time of flight measurements using the white spectrum neutron beam at the LANSCE facility. (To calibrate the apparatus, the TKE release for $^{235}$U(n$_{th}$,f) was also measured using a thermal neutron beam from the OSU TRIGA reactor). The TKE decreases non-linearly from 169.0 MeV to 161.4 MeV for $E_{n}$=2-90 MeV. The standard deviation of the TKE distribution is constant from $E_{n}$=20-90 MeV. Comparison of the data with the multi-modal fission model of Brosa indicates the TKE decrease is a consequence of the growth of symmetric fission and the corresponding decrease of asymmetric fission with increasing neutron energy. The average TKE associated with the Brosa superlong, standard I and standard II modes for a given mass is independent of neutron energy.
Thallmair, Sebastian; Roos, Matthias K; de Vivie-Riedle, Regina
2016-06-21
Quantum dynamics simulations require prior knowledge of the potential energy surface as well as the kinetic energy operator. Typically, they are evaluated in a low-dimensional subspace of the full configuration space of the molecule as its dimensionality increases proportional to the number of atoms. This entails the challenge to find the most suitable subspace. We present an approach to design specially adapted reactive coordinates spanning this subspace. In addition to the essential geometric changes, these coordinates take into account the relaxation of the non-reactive coordinates without the necessity of performing geometry optimizations at each grid point. The method is demonstrated for an ultrafast photoinduced bond cleavage in a commonly used organic precursor for the generation of electrophiles. The potential energy surfaces for the reaction as well as the Wilson G-matrix as part of the kinetic energy operator are shown for a complex chemical reaction, both including the relaxation of the non-reactive coordinates on equal footing. A microscopic interpretation of the shape of the G-matrix elements allows to analyze the impact of the non-reactive coordinates on the kinetic energy operator. Additionally, we compare quantum dynamics simulations with and without the relaxation of the non-reactive coordinates included in the kinetic energy operator to demonstrate its influence. PMID:27334151
Thallmair, Sebastian; Roos, Matthias K.; de Vivie-Riedle, Regina
2016-06-01
Quantum dynamics simulations require prior knowledge of the potential energy surface as well as the kinetic energy operator. Typically, they are evaluated in a low-dimensional subspace of the full configuration space of the molecule as its dimensionality increases proportional to the number of atoms. This entails the challenge to find the most suitable subspace. We present an approach to design specially adapted reactive coordinates spanning this subspace. In addition to the essential geometric changes, these coordinates take into account the relaxation of the non-reactive coordinates without the necessity of performing geometry optimizations at each grid point. The method is demonstrated for an ultrafast photoinduced bond cleavage in a commonly used organic precursor for the generation of electrophiles. The potential energy surfaces for the reaction as well as the Wilson G-matrix as part of the kinetic energy operator are shown for a complex chemical reaction, both including the relaxation of the non-reactive coordinates on equal footing. A microscopic interpretation of the shape of the G-matrix elements allows to analyze the impact of the non-reactive coordinates on the kinetic energy operator. Additionally, we compare quantum dynamics simulations with and without the relaxation of the non-reactive coordinates included in the kinetic energy operator to demonstrate its influence.
Kinetic mean field theories: Results of energy constraint in maximizing entropy
Stell, G.; Karkheck, J.; Beijeren, H. van
1983-01-01
Structure of liquids and solids; crystallography Classical, semiclassical, and quantum theories of liquid structure Statistical theories of liquid structure - Kinetic and transport theory of fluids; physical properties of gases Kinetic and transport theory
International Nuclear Information System (INIS)
Mass and kinetic energy distribution of nuclear fragments after neutron induced fission of 235U have been studied using a Monte-Carlo simulation. Besides that the pronounced peak in the standard deviation of the kinetic energy σE(m) at the mass number around m = 110 was reproduced, a second peak was found at m = 126. These results are in good agreement with experimental data obtained by Belhafaf et. al. We have concluded that the obtained results are consequence of the characteristics of neutron evaporation for the fragments and sharp variation on primary mass yield curve. (authors)
International Nuclear Information System (INIS)
The mass and kinetic energy distribution of nuclear fragments after neutron-induced fission of 235U have been studied using a Monte-Carlo simulation. Besides reproducing the pronounced peak in the standard deviation of the kinetic energy σE(m) at the fragment mass number around m=109, our simulation also produces a second peak at about m=126. These results are in good agreement with experimental data obtained by Belhafaf et.al. We conclude that the obtained results are consequence of the characteristics of the fragments' neutron evaporation and of the sharp variation on the primary mass yield curve. (orig.)
International Nuclear Information System (INIS)
Using the known perturbation series for the idem potent Dirac density matrix in powers of a given one-body potential V (r), Stoddart and March (SM) generated a corresponding series for the kinetic energy density. While the general term of the SM series is known, summation has not been achieved to date. A contribution to this problem is made here by exhibiting an explicit form of the above kinetic energy density for Fermions filling an arbitrary number of closed shells, when the confinement is harmonic. This example is of considerable current interest because of ongoing experiments on ultracold atomic gases of Fermions. (author)
Time-, angle- and kinetic-energy-resolved photoelectron spectroscopy of highly excited states of NO
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We investigate non-adiabatic dynamics of NO molecules that are photo-excited in the vacuum ultraviolet photon energy range using time-resolved velocity map imaging. Highly excited valence and Rydberg states are populated with a tunable (147–151 nm) femtosecond laser pulse and then ionized by a time-delayed near-IR laser pulse. Three main contributions are observed in the photoelectron kinetic spectra with corresponding electron yields that show pronounced oscillations. Two oscillations are assigned to ro-vibronic coupling in the valence-Rydberg mixture of the B′2Δ(v=7) and 4dδ N2Δ(v = 0) states and the B2Π(v = 25) and 4pπ K2Π(v = 1) states, respectively. We assign a third oscillation to originate from a coupling between two Rydberg states. (paper)
Do deep-ocean kinetic energy spectra represent deterministic or stochastic signals?
van Haren, Hans
2016-01-01
In analogy with historic analyses of shallow-water tide-gauge records, in which tides and their higher harmonics are modified by sea level changes induced by atmospheric disturbances, it is shown that deep-sea currents can be interpreted as motions at predominantly inertial-tidal harmonic frequencies modified by slowly varying background conditions. In this interpretation, their kinetic energy spectra may not be smoothed into a quasi-stochastic continuum for (random-)statistic confidence. Instead, they are considered as quasi-deterministic line-spectra. Thus, the climatology of the internal wave field and its slowly varying background can be inferred from line spectra filling the cusps around nonlinear tidal-inertial harmonics, as suggested previously.
International Nuclear Information System (INIS)
The mass distributions of fission fragments from rotating composite nuclear systems with parameters Z2/A > 40 have been calculated in the framework of the diffusion model based on the Fokker-Planck equation for the distribution function of the collective variables. In this formalism the two-body nuclear viscosity coefficient describing the intensity of the dissipative forces is the only free parameter. It has been found that the consideration of the angular momenta of the fissile nuclei leads to a small increase in the calculated widths which slightly improves the agreement with the experimental data. In addition, the fission fragment kinetic-energy distributions have been calculated and compared with the measured ones
Anomalous dissipation and kinetic-energy distribution in pipes at very high Reynolds numbers.
Chen, Xi; Wei, Bo-Bo; Hussain, Fazle; She, Zhen-Su
2016-01-01
A symmetry-based theory is developed for the description of (streamwise) kinetic energy K in turbulent pipes at extremely high Reynolds numbers (Re's). The theory assumes a mesolayer with continual deformation of wall-attached eddies which introduce an anomalous dissipation, breaking the exact balance between production and dissipation. An outer peak of K is predicted above a critical Re of 10^{4}, in good agreement with experimental data. The theory offers an alternative explanation for the recently discovered logarithmic distribution of K. The concept of anomalous dissipation is further supported by a significant modification of the k-ω equation, yielding an accurate prediction of the entire K profile. PMID:26871016
Euler-Lagrange equation from nonlocal-in-time kinetic energy of nonconservative system
International Nuclear Information System (INIS)
This Letter focuses on studying generalized Euler-Lagrange equation and Hamiltonian framework from nonlocal-in-time kinetic energy of nonconservative system. According to Suykens' approach, we extend his results and formulate some work related to the nonconservative system. With the Lagrangian and nonconservative force in nonlocal-in-time form, we obtain the higher order generalized Euler-Lagrange equation which leads to an extension of Newton's second law of motion. The Hamiltonian is studied in relation to the Lagrangian in the canonical phase space. Finally, the particle with nonconservative force case is studied and compared with quantum mechanical results. The extended equation gives a possible approach for understanding the connection between classical and quantum mechanics.
Energy resolution and efficiency of phonon-mediated kinetic inductance detectors for light detection
International Nuclear Information System (INIS)
The development of sensitive cryogenic light detectors is of primary interest for bolometric experiments searching for rare events like dark matter interactions or neutrino-less double beta decay. Thanks to their good energy resolution and the natural multiplexed read-out, Kinetic Inductance Detectors (KIDs) are particularly suitable for this purpose. To efficiently couple KIDs-based light detectors to the large crystals used by the most advanced bolometric detectors, active surfaces of several cm2 are needed. For this reason, we are developing phonon-mediated detectors. In this paper, we present the results obtained with a prototype consisting of four 40 nm thick aluminum resonators patterned on a 2 × 2 cm2 silicon chip, and calibrated with optical pulses and X-rays. The detector features a noise resolution σE = 154 ± 7 eV and an (18 ± 2)% efficiency
Unified dark energy and dust dark matter dual to quadratic purely kinetic K-essence
International Nuclear Information System (INIS)
We consider a modified gravity plus single scalar-field model, where the scalar Lagrangian couples symmetrically both to the standard Riemannian volume-form (spacetime integration measure density) given by the square root of the determinant of the Riemannian metric, as well as to another non-Riemannian volume-form in terms of an auxiliary maximal-rank antisymmetric tensor gauge field. As shown in a previous paper, the pertinent scalar-field dynamics provides an exact unified description of both dark energy via dynamical generation of a cosmological constant, and dark matter as a ''dust'' fluid with geodesic flow as a result of a hidden Noether symmetry. Here we extend the discussion by considering a non-trivial modification of the purely gravitational action in the form of f(R) = R -αR2 generalized gravity. Upon deriving the corresponding ''Einstein-frame'' effective action of the latter modified gravity-scalar-field theory we find explicit duality (in the sense of weak versus strong coupling) between the original model of unified dynamical dark energy and dust fluid dark matter, on one hand, and a specific quadratic purely kinetic ''k-essence'' gravity-matter model with special dependence of its coupling constants on only two independent parameters, on the other hand. The canonical Hamiltonian treatment and Wheeler-DeWitt quantization of the dual purely kinetic ''k-essence'' gravity-matter model is also briefly discussed. (orig.)
Unified dark energy and dust dark matter dual to quadratic purely kinetic K-essence
Energy Technology Data Exchange (ETDEWEB)
Guendelman, Eduardo [Ben-Gurion University of the Negev, Department of Physics, Beersheba (Israel); Nissimov, Emil; Pacheva, Svetlana [Institute for Nuclear Research and Nuclear Energy, Sofia (Bulgaria)
2016-02-15
We consider a modified gravity plus single scalar-field model, where the scalar Lagrangian couples symmetrically both to the standard Riemannian volume-form (spacetime integration measure density) given by the square root of the determinant of the Riemannian metric, as well as to another non-Riemannian volume-form in terms of an auxiliary maximal-rank antisymmetric tensor gauge field. As shown in a previous paper, the pertinent scalar-field dynamics provides an exact unified description of both dark energy via dynamical generation of a cosmological constant, and dark matter as a ''dust'' fluid with geodesic flow as a result of a hidden Noether symmetry. Here we extend the discussion by considering a non-trivial modification of the purely gravitational action in the form of f(R) = R -αR{sup 2} generalized gravity. Upon deriving the corresponding ''Einstein-frame'' effective action of the latter modified gravity-scalar-field theory we find explicit duality (in the sense of weak versus strong coupling) between the original model of unified dynamical dark energy and dust fluid dark matter, on one hand, and a specific quadratic purely kinetic ''k-essence'' gravity-matter model with special dependence of its coupling constants on only two independent parameters, on the other hand. The canonical Hamiltonian treatment and Wheeler-DeWitt quantization of the dual purely kinetic ''k-essence'' gravity-matter model is also briefly discussed. (orig.)
Spontaneous transfer of magnetically stored energy to Kinetic energy by electric double layers
International Nuclear Information System (INIS)
Current disruptions are investigated in a magnetized plasma column with an inductive external electric circuit. It is found that they persist in spite of the fact that each disruption gives rise to a large inductive over-voltage. This drops off at an electric double layer formed in the plasma where most of the magnetic energy, initially stored in the circuit inductance, is released as particle energy. Simultanously as the current disrupts, the potential level at a local potential minimum in the plasma decreases. This is expected to cause the disruption by reflection of electrons. (authors)
Total kinetic energy release in the fast neutron-induced fission of $^{235}$U
Yanez, R; King, J; Barrett, J S; Fotiades, N; Lee, H Y
2016-01-01
We have measured the total kinetic energy (TKE) release for the $^{235}$U(n,f) reaction for $E_{n}$=2-100 MeV using the 2E method with an array of Si PIN diode detectors. The neutron energies were determined by time of flight measurements using the white spectrum neutron beam at the LANSCE facility. To benchmark the TKE measurement, the TKE release for $^{235}$U(n$_{th}$,f) was also measured using a thermal neutron beam from the Oregon State University TRIGA reactor, giving pre-neutron emission $E^*_{TKE}=170.7\\pm0.4$ MeV in good agreement with known values. Our measurements are thus absolute measurements. The TKE in $^{235}$U(n,f) decreases non-linearly from 169.0 MeV to 161.4 MeV for $E_{n}$=2-90 MeV. Comparison of the data with the multi-modal fission model of Brosa indicates the TKE decrease is a consequence of the growth of symmetric fission and the corresponding decrease of asymmetric fission with increasing neutron energy. The average TKE associated with the Brosa superlong, standard I and standard II ...
On renormalization of axial anomaly
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It is shown that multiplicative renormalization of the axial singlet current results in renormalization of the axial anomaly in all orders of perturbation theory. It is a necessary condition for the Adler - Bardeen theorem being valid. 10 refs.; 2 figs
Axial compressor stability enhancement
Houghton, Timothy Oliver.
2010-01-01
Aircraft jet engines must operate in a stable manner at all times. One source of instability is compressor stall. Stall problems can be reduced by machining cavities into the compressor casing adjacent to the rotor blades. This ?casing treatment? is the focus of the present work. Two treatment configurations are tested: circumferential grooves cut into the casing above the rotor blades, and axial slots cut into the casing adjacent to the rotor blade leading edges. The performance of a single ...
AGN JET KINETIC POWER AND THE ENERGY BUDGET OF RADIO GALAXY LOBES
International Nuclear Information System (INIS)
Recent results based on the analysis of radio galaxies and their hot X-ray emitting atmospheres suggest that non-radiating particles dominate the energy budget in the lobes of FR I radio galaxies, in some cases by a factor of more than 1000, while radiating particles dominate the energy budget in FR II radio galaxy lobes. This implies a significant difference in the radiative efficiency of the two morphological classes. To test this hypothesis, we have measured the kinetic energy flux for a sample of 3C FR II radio sources using a new method based on the observed parameters of the jet terminal hotspots, and compared the resulting Qjet-Lradio relation to that obtained for FR I radio galaxies based on X-ray cavity measurements. Contrary to expectations, we find approximate agreement between the Qjet-Lradio relations determined separately for FR I and FR II radio galaxies. This result is ostensibly difficult to reconcile with the emerging scenario in which the lobes of FR I and FR II radio galaxies have vastly different energy budgets. However, a combination of lower density environment, spectral aging and strong shocks driven by powerful FR II radio galaxies may reduce the radiative efficiency of these objects relative to FR Is and counteract, to some extent, the higher radiative efficiency expected to arise due to the lower fraction of energy in non-radiating particles. An unexpected corollary is that extrapolating the Qjet-Lradio relation determined for low power FR I radio galaxies provides a reasonable approximation for high power sources, despite their apparently different lobe compositions.
International Nuclear Information System (INIS)
The dynamical symmetry limit of the two-fluid Interacting Vector Boson Model (IVBM), defined through the chain Sp(12,R) contains U(3,3) contains Up(3) x Un(3) contains SU*(3) contains SO(3), is considered and applied for the description of nuclear collective spectra exhibiting axially asymmetric features. The effect of the introduction of a Majorana interaction to the SU*(3) model Hamiltonian on the γ-band energies is studied. The theoretical predictions are compared with the experimental data for 192Os, 190Os, and 112Ru isotopes. It is shown that by taking into account the full symplectic structures in the considered dynamical symmetry of the IVBM, the proper description of the energy spectra and the γ-band energy staggering of the nuclei under considerations can be achieved. The obtained results show that the potential energy surfaces for the following two nuclei 192Os and 112Ru, possess almost γ-flat potentials with very shallow triaxial minima, suggesting a more complex and intermediate situation between γ-rigid and γ-unstable structures. Additionally, the absolute B(E2) intraband transition probabilities between the states of the ground-state band and γ band, as well as the B(M1) interband transition probabilities between the states of the ground and γ bands for the two nuclei 192Os and 190Os are calculated and compared with experiment and for the B(E2) values with the predictions of some other collective models incorporating the γ-rigid or γ-unstable structures. The obtained results agree well with the experimental data and reveal the relevance of the used dynamical symmetry of IVBM in the description of nuclei exhibiting axially asymmetric features in their spectra. (orig.)
Slawinski, Jean; BONNEFOY, Alice; ONTANON, Guy; LEVEQUE, Jean-Michel; Miller, Christian; RIQUET, Annie; CHEZE, Laurence; Dumas, Raphaël
2010-01-01
The aim of the present study was to measure during a sprint start the joint angularv elocity and the kinetic energy of the different segments in elite sprinters.This was performed using a 3D kinematic analysis of the wholebody.
International Nuclear Information System (INIS)
The average of fragment kinetic energy () and the multiplicity of prompt neutrons (ν(bar sign)) as a function of fragment mass (m*), as well as the fragment mass yield (Y (m*)) from thermal neutron induced fission of 239Pu, have been measured by Tsuchiya et al.. In that work the mass and kinetic energy are calculated from the measured kinetic energy of one fragment and the difference of time of flight of the two complementary fragments. However they do not present their results about the standard deviation σE*(m*). In this work we have made a numerical simulation of that experiment, assuming an initial distribution of the primary fragment kinetic energy (E(A)) with a constant value of the standard deviation as function of fragment mass σE(A)). As a result of that simulation we obtain the dependence σE*(m*) which presents an enhancement between m* = 92 and m* 110, and a peak at m* = 121. (orig.)
International Nuclear Information System (INIS)
The average of fragment kinetic energy (E-bar sign*) and the multiplicity of prompt neutrons (ν(bar sign)) as a function of fragment mass (m*), as well as the fragment mass yield (Y(m*)) from thermal neutron-induced fission of 239Pu have been measured by Tsuchiya et al.. In that work the mass and kinetic energy are calculated from the measured kinetic energy of one fragment and the difference of time of flight of the two complementary fragments. However they do not present their results about the standard deviation σE*(m*). In this work we have made a numerical simulation of that experiment which reproduces its results, assuming an initial distribution of the primary fragment kinetic energy (E(A)) with a constant value of the standard deviation as function of fragment mass (σE(A)). As a result of the simulation we obtain the dependence σE*(m*) which presents an enhancement between m* = 92 and m* = 110, and a peak at m* = 121.
International Nuclear Information System (INIS)
Our research concerns the investigation of bubble-induced turbulence using direct numerical simulation (DNS) of bubbly two-phase flow. DNS computations are performed for the bubble-driven liquid motion induced by a regular train of ellipsoidal bubbles rising through an initially stagnant liquid within a plane channel with two solid walls. DNS data are used to evaluate balance terms in the exact conservation equation for liquid phase turbulence kinetic energy. The evaluation comprises single-phase-like terms (diffusion, dissipation and production) as well as interfacial terms. Special emphasis is placed on the procedure for evaluation of interfacial quantities. Quantitative analysis of the conservation equation of liquid phase turbulence kinetic energy shows the importance of the interfacial terms which are the only source term. The results are further used to validate closure assumptions employed in modelling of the liquid phase turbulence kinetic energy transport in gas-liquid bubbly flows. In this context, performance of respective closure relations in the transport equation for liquid turbulence kinetic energy within the two-phase κ-ε approach is evaluated. (author)
DEFF Research Database (Denmark)
Jensen, K E; Jakobsen, J; Thomsen, C;
1990-01-01
A patient with McArdle's syndrome was examined using bicycle ergometry and 31P NMR spectroscopy during exercise. The patients working capacity was approximately half the expected capacity of controls. Muscle energy kinetics improved significantly during intravenous glucose infusion and after 6...
Andrae, J. C. G.; Johansson, Å.; Björnbom, P.; Rosén, A.
2004-08-01
A kinetic model for the H 2/O 2 reaction on a polycrystalline palladium catalyst has been constructed using CHEMKIN in order to understand the coverage-dependent OH desorption energy. Each adsorbed oxygen atom was modelled to cover four Pd surface sites. The yield of OH and the water production were measured with laser-induced fluorescence (LIF) and microcalorimetry respectively as a function of the relative hydrogen concentration, αH 2. The temperature of the catalyst was 1300 K, the total pressure was 13 Pa and the flow was set to 100 SCCM. In fitting the model to the experimental data, the OH desorption energy EdOH was found to have a first-order coverage dependence according to: EdOH( θ)= EdOH(0)- Bθ, where B is a constant set to 92 kJ/mol. The desorption energy at zero coverage EdOH(0) was determined to be 226 kJ/mol. The model could also qualitatively and quantitatively reproduce the apparent desorption energy as a function of αH 2; therefore it is believed that the coverage could be predicted by the model. The values for EdOH( θ) were calculated as a function of αH 2. From the results of a sensitivity analysis and rate of production calculations, there are strong reasons to believe that the main water-forming reaction on Pd at 1300 K is the hydrogen addition reaction, H + OH ⇌ H 2O. Enthalpy diagrams for the water-forming reactions are also presented.
Maximizing kinetic energy transfer in one-dimensional many-body collisions
International Nuclear Information System (INIS)
The main problem discussed in this paper involves a simple one-dimensional two-body collision, in which the problem can be extended into a chain of one-dimensional many-body collisions. The result is quite interesting, as it provides us with a thorough mathematical understanding that will help in designing a chain system for maximum energy transfer for a range of collision types. In this paper, we will show that there is a way to improve the kinetic energy transfer between two masses, and the idea can be applied recursively. However, this method only works for a certain range of collision types, which is indicated by a range of coefficients of restitution. Although the concept of momentum, elastic and inelastic collision, as well as Newton’s laws, are taught in junior college physics, especially in Singapore schools, students in this level are not expected to be able to do this problem quantitatively, as it requires rigorous mathematics, including calculus. Nevertheless, this paper provides nice analytical steps that address some common misconceptions in students’ way of thinking about one-dimensional collisions. (paper)
On the Exchange of Kinetic and Magnetic Energy Between Clouds and the Interstellar Medium
Miniati, F; Ryu, D; Miniati, Francesco; Ryu, Dongsu
1999-01-01
We investigate, through 2D MHD numerical simulations, the interaction of a uniform magnetic field oblique to a moving interstellar cloud. In particular we explore the transformation of cloud kinetic energy into magnetic energy as a result of field line stretching. Some previous simulations have emphasized the possible dynamical importance of a ``magnetic shield'' formed around clouds when the magnetic field is perpendicular to the cloud motion (Jones et al. 1996, Miniati et al. 1998). It was not clear, however, how dependent those findings were to the assumed field configuration and cloud properties. To expand our understanding of this effect, we examine several new cases by varing the magnetic field orientation angle with respect to the cloud motion (\\theta), the cloud-background density contrast, and the cloud Mach number. We show that in 2D and with \\theta large enough, the magnetic field tension can become dominant in the dynamics of the motion of high density contrast, low Mach number clouds. In such cas...
Directory of Open Access Journals (Sweden)
Katarzyna Chojnacka
2004-01-01
Full Text Available Some microalgae can grow metabolizing inorganic and organic carbon sources, which might occur simultaneously and independently, while energy is supplied by light and/or an organic carbon source. In this context, the contribution of each metabolism to total growth can be determined by quantitative analysis. The illumination of microalgal cells growing in the presence of organic substances, might cause an effect which can drive the carbon metabolism in different ways. When analyzing the growth of different strains of microalgae, some differences could be distinguished, between additive or inhibitory effect of light on heterotrophic metabolism in mixotrophic or photoheterotrophic growth. This manuscript proposes, the integration of a kinetic and stoichiometric metabolic model which explains the differences of carbon and energy utilization modes between mixotrophic and photoheterotrophic growth in microalgae. This model presumably discloses relevant independent facts between the mechanisms of photosynthesis and the oxidative metabolism of organic compounds, such as glucose and the importance of these differences on the production of biomass and secondary metabolites.
Andrade, Tomas; Marolf, Donald
2015-01-01
The gravitational Dirichlet problem -- in which the induced metric is fixed on boundaries at finite distance from the bulk -- is related to simple notions of UV cutoffs in gauge/gravity duality and appears in discussions relating the low-energy behavior of gravity to fluid dynamics. We study the Einstein-Maxwell version of this problem, in which the induced Maxwell potential on the wall is also fixed. For flat walls in otherwise-asymptotically-flat spacetimes, we identify a moduli space of Majumdar-Papapetrou-like static solutions parametrized by the location of an extreme black hole relative to the wall. Such solutions may be described as balancing gravitational repulsion from a negative-mass image-source against electrostatic attraction to an oppositely-signed image charge. Standard techniques for handling divergences yield a moduli space metric with an eigenvalue that becomes negative near the wall, indicating a region of negative kinetic energy and suggesting that the Hamiltonian may be unbounded below. O...
The measurement of rain kinetic energy and rain intensity using an acoustic disdrometer
International Nuclear Information System (INIS)
Microwave engineers and geomorphologists require rainfall data with a much greater temporal resolution and a better representation of the numbers of large raindrops than is available from current commercial instruments. This paper describes an acoustic instrument that determines rain parameters from the sound of raindrops falling into a tank of water. There is a direct relationship between the kinetic energy (KE) of a raindrop and the acoustic energy that it creates upon impact. Rain KE flux density is estimated from measurements of the sound field in the tank, and these have been compared to measurements from a co-sited commercial disdrometer. Eight months of data have been collected in the eastern UK. Comparisons of rain KE estimated by the two instruments are presented and links between the KE and rainfall intensity are discussed. The sampling errors of the two instruments are analysed to show that the acoustic instrument can produce rain KE measurements with a 1 s integration time with sampling uncertainty of the same size as commercial instruments using a 1 min integration time
The horizontal planar structure of kinetic energy in a model vertical-axis wind turbine array
Craig, Anna; Zeller, Robert; Zarama, Francisco; Weitzman, Joel; Dabiri, John; Koseff, Jeffrey
2013-11-01
Recent studies have indicated that arrays of vertical axis wind turbines (VAWTs) could potentially harvest significantly more power per unit land area than arrays composed of conventional horizontal axis wind turbines. However, to design VAWT arrays for optimal power conversion, a more comprehensive understanding of inter-turbine energy transfer is needed. In the presented study, a geometrically scaled array of rotating circular cylinders is used to model a VAWT array. The horizontal inter-cylinder mean fluid velocities and Reynolds stresses are measured on several cross-sections using 2D particle image velocimetry in a flume. Two orientations of the array relative to the incoming flow are tested. The results indicate that cylinder rotation drives asymmetric mean flow patterns within and above the array, resulting in non-uniform distributions of turbulent kinetic energy. The variability is observed to be directly related to the ratio of the cylinder rotation speed to the streamwise water velocity. Emphasis is placed on the implications of the asymmetries for power production. Work supported by a Stanford Graduate Fellowship to A.E.C, by funding to J.O.D. from ONR N000141211047 and the Gordon and Betty Moore Foundation through Grant GBMF2645, and by funding from the Environmental Fluid Mechanics Laboratory, Stanford University.
Axially symmetric SU(3) gravitating skyrmions
Energy Technology Data Exchange (ETDEWEB)
Ioannidou, Theodora [Maths Division, School of Technology, Aristotle University of Thessaloniki, Thessaloniki 54124 (Greece)]. E-mail: ti3@auth.gr; Kleihaus, Burkhard [Institut fuer Physik, Universitaet Oldenburg, Postfach 2503, D-26111 Oldenburg (Germany)]. E-mail: kleihaus@theorie.physik.uni-oldenburg.de; Zakrzewski, Wojtek [Department of Mathematical Sciences, University of Durham, Durham DH1 3LE (United Kingdom)]. E-mail: w.j.zakrzewski@durham.ac.uk
2004-10-21
Axially symmetric gravitating multi-skyrmion configurations are obtained using the harmonic map ansatz introduced in [J. Math. Phys. 40 (1999) 6353]. In particular, the effect of gravity on the energy and baryon densities of the SU(3) non-gravitating multi-skyrmion configurations is studied in detail.
Axially symmetric SU(3) Gravitating Skyrmions
Ioannidou, T A; Zakrzewski, W J; Ioannidou, Theodora; Kleihaus, Burkhard; Zakrzewski, Wojtek
2004-01-01
Axially symmetric gravitating multi-skyrmion configurations are obtained using the harmonic map ansatz introduced in [1]. In particular, the effect of gravity on the energy and baryon densities of the SU(3) non-gravitating multi-skyrmion configurations is studied in detail.
Axially symmetric SU(3) gravitating skyrmions
International Nuclear Information System (INIS)
Axially symmetric gravitating multi-skyrmion configurations are obtained using the harmonic map ansatz introduced in [J. Math. Phys. 40 (1999) 6353]. In particular, the effect of gravity on the energy and baryon densities of the SU(3) non-gravitating multi-skyrmion configurations is studied in detail
Axial Vircator for Electronic Warfare Applications
Directory of Open Access Journals (Sweden)
L. Drazan
2009-12-01
Full Text Available This paper deals with a high power microwave generator with virtual cathode – vircator in axial release for electronic warfare applications. The classification of directed energy weapons microwave (DEWM is introduced together with basic block diagrams of a particular class of DEWM. In the paper, methods for designing vircator pulsed power supply, axial vircator structure, measurement methods and experimental results are presented. The vircator in electromagnetic ammunition is powered by magneto-cumulative generator and in weapons for defense of objects (WDO, it is powered by Marx generator. The possible applications of a vircator in the DEWM area are discussed.
Directory of Open Access Journals (Sweden)
Walt Wells
2008-01-01
Full Text Available Our objective in this paper is to solve a second order differential equation for a long, simply supported column member subjected to a lateral axial load using Heun's numerical method. We will use the solution to find the critical load at which the column member will fail due to buckling. We will calculate this load using Euler's derived analytical approach for an exact solution, as well as Euler's Numerical Method. We will then compare the three calculated values to see how much they deviate from one another. During the critical load calculation, it will be necessary to calculate the moment of inertia for the column member.
EFFICIENCY OF MAGNETIC TO KINETIC ENERGY CONVERSION IN A MONOPOLE MAGNETOSPHERE
International Nuclear Information System (INIS)
Unconfined relativistic outflows from rotating, magnetized compact objects are often well modeled by assuming that the field geometry is approximately a split-monopole at large radii. Earlier work has indicated that such an unconfined flow has an inefficient conversion of magnetic energy to kinetic energy. This has led to the conclusion that ideal magnetohydrodynamical (MHD) processes fail to explain observations of, e.g., the Crab pulsar wind at large radii where energy conversion appears efficient. In addition, as a model for astrophysical jets, the monopole field geometry has been abandoned in favor of externally confined jets since the latter appeared to be generically more efficient jet accelerators. We perform time-dependent axisymmetric relativistic MHD simulations in order to find steady-state solutions for a wind from a compact object endowed with a monopole field geometry. Our simulations follow the outflow for 10 orders of magnitude in distance from the compact object, which is large enough to study both the initial 'acceleration zone' of the magnetized wind as well as the asymptotic 'coasting zone'. We obtain the surprising result that acceleration is actually efficient in the polar region, which develops a jet despite not being confined by an external medium. Our models contain jets that have sufficient energy to account for moderately energetic long and short gamma-ray burst (GRB) events (∼1051-1052 erg), collimate into narrow opening angles (opening half-angle θ j ∼ 0.03 rad), become matter-dominated at large radii (electromagnetic energy flux per unit matter energy flux σ j ∼ 200 for our fiducial model). The simulated jets have γ jθ j ∼ 5-15, so they are in principle capable of generating 'achromatic jet breaks' in GRB afterglow light curves. By defining a 'causality surface' beyond which the jet cannot communicate with a generalized 'magnetic nozzle' near the axis of rotation, we obtain approximate analytical solutions for the Lorentz
Axial instability of rotating relativistic stars
Friedman, J L; Friedman, John L.; Morsink, Sharon M.
1998-01-01
Perturbations of rotating relativistic stars can be classified by their behavior under parity. For axial perturbations (r-modes), initial data with negative canonical energy is found with angular dependence $e^{im\\phi}$ for all values of $m\\geq 2$ and for arbitrarily slow rotation. This implies instability (or marginal stability) of such perturbations for rotating perfect fluids. This low $m$-instability is strikingly different from the instability to polar perturbations, which sets in first for large values of $m$. The timescale for the axial instability appears, for small angular velocity $\\Omega$, to be proportional to a high power of $\\Omega$. As in the case of polar modes, viscosity will again presumably enforce stability except for hot, rapidly rotating neutron stars. This work complements Andersson's numerical investigation of axial modes in slowly rotating stars.
Energy Technology Data Exchange (ETDEWEB)
Olovsson, Weine, E-mail: weine.olovsson@gmail.co [Department of Materials Science and Engineering, Kyoto University, Yoshida Honmachi, Sakyo-ku, Kyoto 606-8501 (Japan); Marten, Tobias [Department of Physics, Chemistry and Biology (IFM), Linkoeping University, SE-581 83 Linkoeping (Sweden); Holmstroem, Erik [Instituto de Fisica, Universidad Austral de Chile, Valdivia (Chile); Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Johansson, Boerje [Department of Physics and Materials Science, Uppsala University, P.O. Box 530, SE-751 21 Uppsala (Sweden); Applied Materials Physics, Department of Materials and Engineering, Royal Institute of Technology (KTH), SE-100 44 Stockholm (Sweden); Abrikosov, Igor A. [Department of Physics, Chemistry and Biology (IFM), Linkoeping University, SE-581 83 Linkoeping (Sweden)
2010-05-15
We present a brief overview of recent theoretical studies of the core-level binding energy shift (CLS) in solid metallic materials. The focus is on first principles calculations using the complete screening picture, which incorporates the initial (ground state) and final (core-ionized) state contributions of the electron photoemission process in X-ray photoelectron spectroscopy (XPS), all within density functional theory (DFT). Considering substitutionally disordered binary alloys, we demonstrate that on the one hand CLS depend on average conditions, such as volume and overall composition, while on the other hand they are sensitive to the specific local atomic environment. The possibility of employing layer resolved shifts as a tool for characterizing interface quality in fully embedded thin films is also discussed, with examples for CuNi systems. An extension of the complete screening picture to core-core-core Auger transitions is given, and new results for the influence of local environment effects on Auger kinetic energy shifts in fcc AgPd are presented.
An Unbroken Axial-Vector Current Conservation Law
Sharafiddinov, Rasulkhozha S.
2016-04-01
The mass, energy and momentum of the neutrino of a true flavor have an axial-vector nature. As a consequence, the left-handed truly neutral neutrino in an axial-vector field of emission can be converted into a right-handed one and vice versa. This predicts the unidenticality of masses, energies and momenta of neutrinos of the different components. Recognizing such a difference in masses, energies, momenta and accepting that the left-handed axial-vector neutrino and the right-handed antineutrino of true neutrality refer to long-lived C-odd leptons, and the right-handed truly neutral neutrino and the left-handed axial-vector antineutrino are of short-lived fermions of C-oddity, we would write a new CP-even Dirac equation taking into account the flavor symmetrical axial-vector mass, energy and momentum matrices. Their presence explains the spontaneous mirror symmetry violation, confirming that an axial-vector current conservation law has never violated. They reflect the availability of a mirror Minkowski space in which a neutrino is characterized by left as well as by right space-time coordinates. Therefore, it is not surprising that whatever the main purposes experiments about a quasielastic axial-vector mass say in favor of an axial-vector mirror Minkowski space-time.
Trapped Particle Stability for the Kinetic Stabilizer
Berk, H L
2011-01-01
A kinetically stabilized axially symmetric tandem mirror (KSTM) uses the momentum flux of low-energy, unconfined particles that sample only the outer end-regions of the mirror plugs, where large favorable field-line curvature exists. The window of operation is determined for achieving MHD stability with tolerable energy drain from the kinetic stabilizer. Then MHD stable systems are analyzed for stability of the trapped particle mode. This mode is characterized by the detachment of the central-cell plasma from the kinetic stabilizer region without inducing field-line bending. Stability of the trapped particle mode is sensitive to the electron connection between the stabilizer and the end plug. It is found that the stability condition for the trapped particle mode is more constraining than the stability condition for the MHD mode, and it is challenging to satisfy the required power constraint. Furthermore a severe power drain may arise from the necessary connection of low-energy electrons in the kinetic stabili...
Trapped particle stability for the kinetic stabilizer
Berk, H. L.; Pratt, J.
2011-08-01
A kinetically stabilized axially symmetric tandem mirror (KSTM) uses the momentum flux of low-energy, unconfined particles that sample only the outer end-regions of the mirror plugs, where large favourable field-line curvature exists. The window of operation is determined for achieving magnetohydrodynamic (MHD) stability with tolerable energy drain from the kinetic stabilizer. Then MHD stable systems are analysed for stability of the trapped particle mode. This mode is characterized by the detachment of the central-cell plasma from the kinetic-stabilizer region without inducing field-line bending. Stability of the trapped particle mode is sensitive to the electron connection between the stabilizer and the end plug. It is found that the stability condition for the trapped particle mode is more constraining than the stability condition for the MHD mode, and it is challenging to satisfy the required power constraint. Furthermore, a severe power drain may arise from the necessary connection of low-energy electrons in the kinetic stabilizer to the central region.
Trapped particle stability for the kinetic stabilizer
International Nuclear Information System (INIS)
A kinetically stabilized axially symmetric tandem mirror (KSTM) uses the momentum flux of low-energy, unconfined particles that sample only the outer end-regions of the mirror plugs, where large favourable field-line curvature exists. The window of operation is determined for achieving magnetohydrodynamic (MHD) stability with tolerable energy drain from the kinetic stabilizer. Then MHD stable systems are analysed for stability of the trapped particle mode. This mode is characterized by the detachment of the central-cell plasma from the kinetic-stabilizer region without inducing field-line bending. Stability of the trapped particle mode is sensitive to the electron connection between the stabilizer and the end plug. It is found that the stability condition for the trapped particle mode is more constraining than the stability condition for the MHD mode, and it is challenging to satisfy the required power constraint. Furthermore, a severe power drain may arise from the necessary connection of low-energy electrons in the kinetic stabilizer to the central region.
Indian Academy of Sciences (India)
Rohit Jain; Deepika Bhandari; N S Saxena; S K Sharma; A Tripathi
2001-02-01
Differential scanning calorimeter (DSC) is employed to study the crystallization kinetics of irradiated (at three different fluences with high-energy heavy ion; Ni11+ of 150 MeV) specimens of two Co-based metallic glasses. It is found that the crystallization process in both the glasses is completed in two phases. The DSC data have been analysed in terms of kinetic parameters viz. activation energy (), Avrami exponent (), dimensionality of growth (), using two different theoretical models. The results obtained have been compared with that of virgin samples. The lower activation energy in case of second crystallization occurring at higher temperature indicates the easier nucleation of second phase. The abnormally high value of Avrami exponent in Co–Ni glass indicates very high nucleation rate during first crystallization.
International Nuclear Information System (INIS)
The effect of attenuating the energy of a 10 MeV electron beam on Salmonella inactivation kinetics was investigated. No statistically significant differences were observed between the D10 values of either Salmonella 4,[5],12:i:- or a Salmonella cocktail (S. 4,[5],12:i:-, Salmonella Heidelberg, Salmonella Newport, Salmonella Typhimurium, Salmonella) when irradiated with either a non-attenuated 10 MeV eBeam or an attenuated 10 MeV eBeam (~2.9±0.22 MeV). The results show that attenuating the energy of a 10 MeV eBeam to achieve low doses does not affect the inactivation kinetics of Salmonella spp. when compared to direct 10 MeV eBeam irradiation. - Highlights: • 10 MeV eBeam energy was attenuated to 2.9±0.22 MeV using HDPE sheets. • Attenuation of eBeam energy does not affect the inactivation kinetics of Salmonella. • Microbial inactivation is independent of eBeam energy in the range of 3–10 MeV
A nonlinear MEMS electrostatic kinetic energy harvester for human-powered biomedical devices
Energy Technology Data Exchange (ETDEWEB)
Lu, Y.; Cottone, F.; Marty, F.; Basset, P., E-mail: p.basset@esiee.fr [Université Paris-Est/ESYCOM/ESIEE Paris, Noisy-le-Grand 93162 (France); Boisseau, S. [CEA, Leti, Minatec Campus, Grenoble 38054 (France); Galayko, D. [UPMC-Sorbonne Université/LIP 6, CNRS, Paris 75005 (France)
2015-12-21
This article proposes a silicon-based electrostatic kinetic energy harvester with an ultra-wide operating frequency bandwidth from 1 Hz to 160 Hz. This large bandwidth is obtained, thanks to a miniature tungsten ball impacting with a movable proof mass of silicon. The motion of the silicon proof mass is confined by nonlinear elastic stoppers on the fixed part standing against two protrusions of the proof mass. The electrostatic transducer is made of interdigited-combs with a gap-closing variable capacitance that includes vertical electrets obtained by corona discharge. Below 10 Hz, the e-KEH offers 30.6 nJ per mechanical oscillation at 2 g{sub rms}, which makes it suitable for powering biomedical devices from human motion. Above 10 Hz and up to 162 Hz, the harvested power is more than 0.5 μW with a maximum of 4.5 μW at 160 Hz. The highest power of 6.6 μW is obtained without the ball at 432 Hz, in accordance with a power density of 142 μW/cm{sup 3}. We also demonstrate the charging of a 47-μF capacitor to 3.5 V used to power a battery-less wireless temperature sensor node.
Study of Some Simple Approximations to the Non-Interacting Kinetic Energy Functional
Salazar, Edison X; Ludeña, Eduardo V; Cornejo, Mauricio; Karasiev, Valentin V
2016-01-01
Within the framework of density functional theory, we present a study of approximations to the enhancement factor of the non-interacting kinetic energy functional $T_s[\\rho]$. For this purpose, we employ the model of Liu and Parr [S. Liu and R.G. Parr, Phys. Rev. A {\\bf 55}, 1792 (1997)] based on a series expansion of $T_s[\\rho]$ involving powers of the density. Applications to 34 atoms, at the Hartree-Fock level showed that the enhancement factors present peaks that are in excellent agreement with those of the exact ones and give an accurate description of the shell structure of these atoms. The application of Z-dependent expansions to represent some of the terms of these approximation for neutral atoms and for positive and negative ions, which allows $T_s[\\rho]$ to be cast in a very simple form, is also explored. Indications are given as to how these functionals may be applied to molecules and clusters
Scott, Robert B.
2010-01-01
We compare the total kinetic energy (TKE) in four global eddying ocean circulation simulations with a global dataset of over 5000, quality controlled, moored current meter records. At individual mooring sites, there was considerable scatter between models and observations that was greater than estimated statistical uncertainty. Averaging over all current meter records in various depth ranges, all four models had mean TKE within a factor of two of observations above 3500. m, and within a factor of three below 3500. m. With the exception of observations between 20 and 100. m, the models tended to straddle the observations. However, individual models had clear biases. The free running (no data assimilation) model biases were largest below 2000. m. Idealized simulations revealed that the parameterized bottom boundary layer tidal currents were not likely the source of the problem, but that reducing quadratic bottom drag coefficient may improve the fit with deep observations. Data assimilation clearly improved the model-observation comparison, especially below 2000. m, despite assimilated data existing mostly above this depth and only south of 47°N. Different diagnostics revealed different aspects of the comparison, though in general the models appeared to be in an eddying-regime with TKE that compared reasonably well with observations. © 2010 Elsevier Ltd.
Zhang, Yanwei; Xu, Huiping; Qin, Rufu; Xu, Changwei; Fan, Daidu
2016-01-01
The East China Sea (ECS) has a high suspended-sediment concentration because of the influence of the Changjiang River, indicated by high turbidity in the water. Considering the islands offthe coast and the complex topography, and the strong influence of tides and wind, the coast offthe ECS is a typical region with strong oceanic mixing processes. The changes in the dynamic processes near the bottom play an important role in the control of water turbidity. The turbulent kinetic energy dissipation rate ( ɛ ) is a parameter that shows the strength of ocean mixing. This is estimated based on a structure method using current velocity that is measured by a high-frequency Acoustic Doppler Current Profiler (ADCP) from a seafloor observatory in the ECS. The results indicate strong ocean mixing processes with a mean ɛ value of 5.7×10-5 W/kg and distinct tidal variations in the dissipation rate. Conversely, the variation of the water turbidity leads to changes in the water dynamical structure near the bottom. Comparing the dissipation rate with the turbidity near the bottom boundary layer, we find that the high turbidity mimics strong ocean mixing.
On the mean kinetic energy of the proton in strong hydrogen bonded systems
International Nuclear Information System (INIS)
The mean atomic kinetic energies of the proton, Ke(H), and of the deuteron, Ke(D), were calculated in moderate and strongly hydrogen bonded (HB) systems, such as the ferro-electric crystals of the KDP type (XH2PO4, X = K, Cs, Rb, Tl), the DKDP (XD2PO4, X = K, Cs, Rb) type, and the X3H(SO4)2 superprotonic conductors (X = K, Rb). All calculations utilized the simulated partial phonon density of states, deduced from density functional theory based first-principle calculations and from empirical lattice dynamics simulations in which the Coulomb, short range, covalent, and van der Waals interactions were accounted for. The presently calculated Ke(H) values for the two systems were found to be in excellent agreement with published values obtained by deep inelastic neutron scattering measurements carried out using the VESUVIO instrument of the Rutherford Laboratory, UK. The Ke(H) values of the M3H(SO4)2 compounds, in which the hydrogen bonds are centro-symmetric, are much lower than those of the KDP type crystals, in direct consistency with the oxygen-oxygen distance ROO, being a measure of the HB strength
On the mean kinetic energy of the proton in strong hydrogen bonded systems
Energy Technology Data Exchange (ETDEWEB)
Finkelstein, Y. [Nuclear Research Center–Negev, Beer-Sheva 84190 (Israel); Moreh, R. [Physics Department, Ben-Gurion University of the Negev, Beer-Sheva 84105 (Israel); Shang, S. L.; Wang, Y.; Liu, Z. K. [Department of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802 (United States); Shchur, Ya. [Institute for Condensed Matter Physics, 1 Svientsitskii str., L’viv 79011 (Ukraine)
2016-02-07
The mean atomic kinetic energies of the proton, Ke(H), and of the deuteron, Ke(D), were calculated in moderate and strongly hydrogen bonded (HB) systems, such as the ferro-electric crystals of the KDP type (XH{sub 2}PO{sub 4}, X = K, Cs, Rb, Tl), the DKDP (XD{sub 2}PO{sub 4}, X = K, Cs, Rb) type, and the X{sub 3}H(SO{sub 4}){sub 2} superprotonic conductors (X = K, Rb). All calculations utilized the simulated partial phonon density of states, deduced from density functional theory based first-principle calculations and from empirical lattice dynamics simulations in which the Coulomb, short range, covalent, and van der Waals interactions were accounted for. The presently calculated Ke(H) values for the two systems were found to be in excellent agreement with published values obtained by deep inelastic neutron scattering measurements carried out using the VESUVIO instrument of the Rutherford Laboratory, UK. The Ke(H) values of the M{sub 3}H(SO{sub 4}){sub 2} compounds, in which the hydrogen bonds are centro-symmetric, are much lower than those of the KDP type crystals, in direct consistency with the oxygen-oxygen distance R{sub OO}, being a measure of the HB strength.
Turbulence kinetic energy budget in bubbly flows in a vertical duct
Energy Technology Data Exchange (ETDEWEB)
Hosokawa, Shigeo; Suzuki, Takashi; Tomiyama, Akio [Graduate School of Engineering, Kobe University, Department of Mechanical Engineering, Kobe, Hyogo (Japan)
2012-03-15
Understanding turbulence kinetic energy (TKE) budget in gas-liquid two-phase bubbly flows is indispensable to develop and improve turbulence models for the bubbly flows. In this study, a molecular tagging velocimetry based on photobleaching reaction was applied to turbulent bubbly flows with sub-millimeter bubbles in a vertical square duct to examine the applicability of the k-{epsilon} models to the bubbly flows. Effects of bubbles on TKE budget are discussed and a priori tests of the standard and low Reynolds number k-{epsilon} models are carried out to examine the applicability of these models to the bubbly flows. The conclusions obtained are as follows: (1) The photobleaching molecular tagging velocimetry is of use for validating turbulence models. (2) The bubbles increase the liquid velocity gradient in the near wall region, and therefore, enhance the production and dissipation rates of TKE. (3) The k-{epsilon} models can reasonably evaluate the production rate of TKE in the bubbly flows. (4) The modulations of diffusion due to the bubbles have different characteristics from the diffusion enhancement due to shear-induced turbulence. Hence, the k-{epsilon} models fail in evaluating the diffusion rate in the near wall region in the bubbly flows. (5) The k-{epsilon} models represent the trends of the production, dissipation, and diffusion rates of {epsilon} in the bubbly flow, although more accurate experimental data are required for quantitative validation of the {epsilon} equation. (orig.)
Connectivity of Marine Protected Areas and Its Relation with Total Kinetic Energy
D’Agostini, Andressa; Gherardi, Douglas Francisco Marcolino; Pezzi, Luciano Ponzi
2015-01-01
The East Continental Shelf (ECS) of Brazil is a hotspot of endemism and biodiversity of reef biota in the South Atlantic, hosting a number of Marine Protected Areas (MPAs). Connectivity of MPAs through larval dispersal influences recruitment, population dynamics, genetic structure and biogeography in coral reef ecosystems. Connectivity of protected reef ecosystem in the ECS was investigated with a hydrodynamic model (ROMS) forcing an Individual Based Model (IBM—Ichthyop), and used groupers (genus Mycteroperca) as functional group. The hydrodynamic output from ROMS was compared with satellite data and showed good agreement with observed surface fields. Eggs were released, in IBM experiments, from April to September along six years (2002–2007) in five MPAs along the ECS. Intrannual variability in recruitment and self-recruitment of grouper larvae was observed, as well as a negative correlation of these population parameters with total Kinetic Energy (KE) used as a metric of the physical environment. Higher KE leads to increased offshore advection of larvae, reduced total recruitment and connectivity of MPAs. Our results indicate high and uni-directional connectivity between MPAs from north to south influenced by the Brazil Current flowing in the same direction. Results also showed that some MPAs act predominantly as “sink” while others are mainly “source” areas. PMID:26448650
A nonlinear MEMS electrostatic kinetic energy harvester for human-powered biomedical devices
Lu, Y.; Cottone, F.; Boisseau, S.; Marty, F.; Galayko, D.; Basset, P.
2015-12-01
This article proposes a silicon-based electrostatic kinetic energy harvester with an ultra-wide operating frequency bandwidth from 1 Hz to 160 Hz. This large bandwidth is obtained, thanks to a miniature tungsten ball impacting with a movable proof mass of silicon. The motion of the silicon proof mass is confined by nonlinear elastic stoppers on the fixed part standing against two protrusions of the proof mass. The electrostatic transducer is made of interdigited-combs with a gap-closing variable capacitance that includes vertical electrets obtained by corona discharge. Below 10 Hz, the e-KEH offers 30.6 nJ per mechanical oscillation at 2 grms, which makes it suitable for powering biomedical devices from human motion. Above 10 Hz and up to 162 Hz, the harvested power is more than 0.5 μW with a maximum of 4.5 μW at 160 Hz. The highest power of 6.6 μW is obtained without the ball at 432 Hz, in accordance with a power density of 142 μW/cm3. We also demonstrate the charging of a 47-μF capacitor to 3.5 V used to power a battery-less wireless temperature sensor node.
A nonlinear MEMS electrostatic kinetic energy harvester for human-powered biomedical devices
International Nuclear Information System (INIS)
This article proposes a silicon-based electrostatic kinetic energy harvester with an ultra-wide operating frequency bandwidth from 1 Hz to 160 Hz. This large bandwidth is obtained, thanks to a miniature tungsten ball impacting with a movable proof mass of silicon. The motion of the silicon proof mass is confined by nonlinear elastic stoppers on the fixed part standing against two protrusions of the proof mass. The electrostatic transducer is made of interdigited-combs with a gap-closing variable capacitance that includes vertical electrets obtained by corona discharge. Below 10 Hz, the e-KEH offers 30.6 nJ per mechanical oscillation at 2 grms, which makes it suitable for powering biomedical devices from human motion. Above 10 Hz and up to 162 Hz, the harvested power is more than 0.5 μW with a maximum of 4.5 μW at 160 Hz. The highest power of 6.6 μW is obtained without the ball at 432 Hz, in accordance with a power density of 142 μW/cm3. We also demonstrate the charging of a 47-μF capacitor to 3.5 V used to power a battery-less wireless temperature sensor node
Energy resolution and efficiency of phonon-mediated kinetic inductance detectors for light detection
Energy Technology Data Exchange (ETDEWEB)
Cardani, L., E-mail: laura.cardani@roma1.infn.it [Dipartimento di Fisica, Sapienza Università di Roma, Piazzale Aldo Moro 2, 00185 Roma (Italy); Physics Department, Princeton University, Washington Road, 08544, Princeton, New Jersey (United States); Colantoni, I.; Coppolecchia, A. [Dipartimento di Fisica, Sapienza Università di Roma, Piazzale Aldo Moro 2, 00185 Roma (Italy); Cruciani, A.; Vignati, M.; Bellini, F.; Casali, N.; Cosmelli, C. [Dipartimento di Fisica, Sapienza Università di Roma, Piazzale Aldo Moro 2, 00185 Roma (Italy); INFN - Sezione di Roma, Piazzale Aldo Moro 2, 00185 Roma (Italy); Di Domizio, S. [Dipartimento di Fisica, Università degli Studi di Genova, Via Dodecaneso 33, 16146 Genova (Italy); INFN - Sezione di Genova, Via Dodecaneso 33, 16146 Genova (Italy); Castellano, M. G. [Istituto di Fotonica e Nanotecnologie - CNR, Via Cineto Romano 42, 00156 Roma (Italy); Tomei, C. [INFN - Sezione di Roma, Piazzale Aldo Moro 2, 00185 Roma (Italy)
2015-08-31
The development of sensitive cryogenic light detectors is of primary interest for bolometric experiments searching for rare events like dark matter interactions or neutrino-less double beta decay. Thanks to their good energy resolution and the natural multiplexed read-out, Kinetic Inductance Detectors (KIDs) are particularly suitable for this purpose. To efficiently couple KIDs-based light detectors to the large crystals used by the most advanced bolometric detectors, active surfaces of several cm{sup 2} are needed. For this reason, we are developing phonon-mediated detectors. In this paper, we present the results obtained with a prototype consisting of four 40 nm thick aluminum resonators patterned on a 2 × 2 cm{sup 2} silicon chip, and calibrated with optical pulses and X-rays. The detector features a noise resolution σ{sub E} = 154 ± 7 eV and an (18 ± 2)% efficiency.
Yue, Ping; Zhang, Qiang; Wang, Runyuan; Li, Yaohui; Wang, Sheng
2015-09-01
A deep understanding of turbulence structure is important for investigating the characteristics of the atmospheric boundary layer, especially over heterogeneous terrain. In the present study, turbulence intensity and turbulent kinetic energy (TKE) parameters are analyzed for different conditions with respect to stability, wind direction and wind speed over a valley region of the Loess Plateau of China during December 2003 and January 2004. The purpose of the study is to examine whether the observed turbulence intensity and TKE parameters satisfy Monin-Obukhov similarity theory (MOST), and analyze the wind shear effect on, and thermal buoyancy function of, the TKE, despite the terrain heterogeneity. The results demonstrate that the normalized intensity of turbulence follows MOST for all stability in the horizontal and vertical directions, as well as the normalized TKE in the horizontal direction. The shear effect of the wind speed in the Loess Plateau region is strong in winter and could enhance turbulence for all stability conditions. During daytime, the buoyancy and shear effect together constitute the generation of TKE under unstable conditions. At night, the contribution of buoyancy to TKE is relatively small, and mechanical shearing is the main production form of turbulence.
Production and destruction of eddy kinetic energy in forced submesoscale eddy-resolving simulations
Mukherjee, Sonaljit; Ramachandran, Sanjiv; Tandon, Amit; Mahadevan, Amala
2016-09-01
We study the production and dissipation of the eddy kinetic energy (EKE) in a submesoscale eddy field forced with downfront winds using the Process Study Ocean Model (PSOM) with a horizontal grid resolution of 0.5 km. We simulate an idealized 100 m deep mixed-layer front initially in geostrophic balance with a jet in a domain that permits eddies within a range of O(1 km-100 km). The vertical eddy viscosities and the dissipation are parameterized using four different subgrid vertical mixing parameterizations: the k - ɛ , the KPP, and two different constant eddy viscosity and diffusivity profiles with a magnitude of O(10-2m2s-1) in the mixed layer. Our study shows that strong vertical eddy viscosities near the surface reduce the parameterized dissipation, whereas strong vertical eddy diffusivities reduce the lateral buoyancy gradients and consequently the rate of restratification by mixed-layer instabilities (MLI). Our simulations show that near the surface, the spatial variability of the dissipation along the periphery of the eddies depends on the relative alignment of the ageostrophic and geostrophic shear. Analysis of the resolved EKE budgets in the frontal region from the simulations show important similarities between the vertical structure of the EKE budget produced by the k - ɛ and KPP parameterizations, and earlier LES studies. Such an agreement is absent in the simulations using constant eddy-viscosity parameterizations.
Impact of Nocturnal Low-Level Jets on Near-Surface Turbulence Kinetic Energy
Duarte, Henrique F.; Leclerc, Monique Y.; Zhang, Gengsheng; Durden, David; Kurzeja, Robert; Parker, Matthew; Werth, David
2015-09-01
We report on the role of low-level jets (LLJs) on the modulation of near-surface turbulence in the stable boundary layer, focusing on the behaviour of the transport terms of the turbulence kinetic energy (TKE) budget. We also examine the applicability of Monin-Obukhov similarity theory (MOST) in light of these terms. Using coincident near-surface turbulence and LLJ data collected over a three-month period in South Carolina, USA, we found that turbulence during LLJ periods was typically stronger and more well-developed in comparison with periods without a LLJ. We found a local imbalance in the near-surface TKE budget, in which the imbalance (residual) term was typically positive (i.e., energy gain) and nearly in equilibrium with buoyant consumption. Based on a comparison with previous studies, we assume that this residual term represents mostly pressure transport. We found the behaviour of the residual term to be better delineated in the presence of LLJs. We found shear production to adhere to MOST remarkably well during LLJs, except under very stable conditions. Gain of non-local TKE via pressure transport, likely consisting of large-scale fluctuations, could be the cause of the observed deviation from the MOST -less prediction. The fact that this deviation was observed for periods with well-developed turbulence with an inertial subrange slope close to indicates that such Kolmogorov turbulence is not a sufficient condition to guarantee the applicability of the MOST -less concept, as recently suggested in the literature. The implications of these results are discussed.
Che, H; Viñas, A F
2013-01-01
The observed sub-proton scale turbulence spectrum in the solar wind raises the question of how that turbulence originates. Observations of keV energetic electrons during solar quite-time suggest them as possible source of free energy to drive the turbulence. Using particle-in-cell simulations, we explore how free energy in energetic electrons, released by an electron two-stream instability drives Weibel-like electromagnetic waves that excite wave-wave interactions. Consequently, both kinetic Alfv\\'enic and whistler waves are excited that evolve through inverse and forward magnetic energy cascades.
Axial skeletal CT densitometry
International Nuclear Information System (INIS)
Since the discovery of the Roentgen ray a precise and accurate assessment of bone mineral content has been a challenge to many investigators. A number of methods have been developed but no one satisfied. Considering its technical possibilities computed tomography is very promising in determination of bone mineral content (BMC). The new modality enables BMC estimations in the axial skeletal trabecular bone. CT densitometry can be performed on a normal commercially available third generation whole body CT scanner. No dedicated device in a special clinical set-up is necessary. In this study 106 patients, most of them clinically suspected of osteoporosis, were examined. The new method CT densitometry has been evaluated. The results have been correlated to alternative BMC determination methods. (Auth.)
Correlated Signals at the Energy and Intensity Frontiers from Nonabelian Kinetic Mixing
Barello, G; Newby, Christopher A
2015-01-01
We show that when a dark abelian gauge sector and SU$(2)_{L}$ kinetically mix it necessarily generates a relation between the kinetic mixing strength and the mass of the mediating particle. Remarkably, this correspondence maps the weak scale directly to the kinetic mixing strengths being probed by modern fixed-target experiments and next generation flavor factories. This illuminates the exciting possibility of correlated discoveries of a new particle at the LHC and a dark photon at intensity frontier experiments. To motivate the scenario, we construct a simple model and explore its phenomenology and constraints.
Frost, W.; Harper, W. L.
1975-01-01
Flow over surface obstructions can produce significantly large wind shears such that adverse flying conditions can occur for aeronautical systems (helicopters, STOL vehicles, etc.). Atmospheric flow fields resulting from a semi-elliptical surface obstruction in an otherwise horizontally homogeneous statistically stationary flow are modelled with the boundary-layer/Boussinesq-approximation of the governing equation of fluid mechanics. The turbulence kinetic energy equation is used to determine the dissipative effects of turbulent shear on the mean flow. Iso-lines of turbulence kinetic energy and turbulence intensity are plotted in the plane of the flow and highlight regions of high turbulence intensity in the stagnation zone and sharp gradients in intensity along the transition from adverse to favourable pressure gradient. Discussion of the effects of the disturbed wind field in CTOL and STOL aircraft flight path and obstruction clearance standards is given. The results indicate that closer inspection of these presently recommended standards as influenced by wind over irregular terrains is required.
Coutinho, Nayara D; Silva, Valter H C; de Oliveira, Heibbe C B; Camargo, Ademir J; Mundim, Kleber C; Aquilanti, Vincenzo
2015-05-01
The OH + HBr → H2O + Br reaction, prototypical of halogen-atom liberating processes relevant to mechanisms for atmospheric ozone destruction, attracted frequent attention of experimental chemical kinetics: the nature of the unusual reactivity drop from low to high temperatures eluded a variety of theoretical efforts, ranking this one among the most studied four-atom reactions. Here, inspired by oriented molecular-beams experiments, we develop a first-principles stereodynamical approach. Thermalized sets of trajectories, evolving on a multidimensional potential energy surface quantum mechanically generated on-the-fly, provide a map of most visited regions at each temperature. Visualizations of rearrangements of bonds along trajectories and of the role of specific angles of reactants' mutual approach elucidate the mechanistic change from the low kinetic energy regime (where incident reactants reorient to find the propitious alignment leading to reaction) to high temperature (where speed hinders adjustment of directionality and roaming delays reactivity). PMID:26263312
Kinetic Energy Driven Superconductivity in the Electron Doped Cobaltate NaxCoO2 · yH2O
Institute of Scientific and Technical Information of China (English)
LIU Bin; LIANG Ying; FENG Shi-Ping; CHEN Wei-Yeu
2005-01-01
Within the charge-spin separation fermion-spin theory, we show that the mechanism of superconductivity in the electron doped cobaltate Nax CoO2. yH2 O is ascribed to its kinetic energy. The dressed fermions interact occurring directly through the kinetic energy by exchanging magnetic excitations. This interaction leads to a net attractive force between dressed fermions, then the electron Cooper pairs originating from the dressed fermion pairing state are due to the charge-spin recombination, and their condensation reveals the superconducting ground state. The superconducting transition temperature is identical to the dressed fermion pair transition temperature, and is suppressed to a lower temperature due to the strong magnetic frustration. The optimal superconducting transition temperature occurs in the electron doping concentration δ≈ 0.29, and then decreases for both underdoped and overdoped regimes, in qualitative agreement with the experimental results.
Indian Academy of Sciences (India)
Maryam Abareshi; Seyed Mojtaba Zebarjad; Elaheh K Goharshadi
2014-08-01
Non-isothermal crystallization kinetics of pure medium density polyethylene (MDPE) and MDPE–clay nanocomposites have been investigated by differential scanning calorimeter. The modified Avrami, Ozawa, Liu and Ziabicki equations have been applied to describe non-isothermal crystallization process. The results of Avrami analysis showed a very complicated crystallization mechanism. Although, Ozawa equation failed to provide an adequate description for non-isothermal crystallization process, Liu equation could describe it well. The data showed the crystallization rate of MDPE and nanocomposites raises with increasing cooling rate and the crystallization rate of nanocomposite is faster than that of MDPE at a given cooling rate. Ziabicki’s kinetic crystallizability index showed that clay can increase the ability of MDPE to crystallize, when it is cooled at unit cooling rate. The activation energy of samples has been evaluated by Kissinger method. The results showed that the activation energy of nanocomposite was lower than that of MDPE.
Buoyant Turbulent Kinetic Energy Production in Steep-Slope Katabatic Flow
Oldroyd, Holly J.; Pardyjak, Eric R.; Higgins, Chad W.; Parlange, Marc B.
2016-07-01
We develop several critical concepts that should be considered when interpreting, modelling and designing future experiments for flows over sloping terrain. Vertical buoyancy fluxes in katabatic flows can be positive and a source of turbulent kinetic energy (TKE) despite the statically stable, thermal stratification that drives these flows. This phenomenon occurs when the ratio of along-slope to slope-normal kinematic heat fluxes is greater than the cotangent of the slope angle, suggesting a critical value of slope-angle steepness found in earlier studies. We provide field-data-based evidence that the along-slope heat flux may dominate the variables in this inequality, and therefore in generating buoyant TKE production or suppression over a steep slope. These data show the along-slope heat flux can be more variable and significantly larger in magnitude than the slope-normal component. The gradient Richardson number does not include the effects of the along-slope buoyancy; furthermore, none of the canonical stability parameters can properly reflect the TKE redistribution from turbulent transport divergence and the sink of TKE in cases of counter-gradient momentum fluxes, which we frequently observe near the peak of the katabatic jet. In such cases, canonical stability parameters inadequately represent the physical mechanisms associated with stability. These results have broad implications related to accurately modelling turbulence and surface exchanges over sloping terrain and illustrate the need to more thoroughly investigate the along-slope heat flux and its drivers, the meaning and definitions of stability, and the effects of non-local turbulent transport.
SNG from coal: thermodynamic and kinetic constraints; use of nuclear energy
International Nuclear Information System (INIS)
Part I contains an analysis of the thermodynamic constraints of converting coal to SNG. It is shown that the thermodynamic constraints that limit the thermal efficiency are not inherent, but are the result of design decisions, based on available technology, as well as on the kinetic properties of available catalysts. The latter, limits the yield of methane to that obtainable at global equilibrium over carbon in the presence of CO, H2, CO2 and H2O. The equilibrium composition is shown to be independent of the thermodynamic properties of the char or coal fed. These limitations give the nonisothermal two-stage processes significant thermodynamic advantages. The analysis in part I results in suggesting directions for modifying present processes in order to obtain higher thermal efficiences. It also presents two-stage process schemes which may have significant advantages over present technology. As the methodology used for the thermodynamic analysis contains some novel elements, it should be of interest to the reaction engineer in general, and should be applicable to a wide range of catalytic and noncatalytic processes. Part II focuses on the use of nuclear energy in the production of synthetic fuel. Two processes for the production of hydrogen (which is used in coal-to-SNG processes) are analyzed and compared. The two processes are: 1) hydrogen from electrolysis of water using nuclear heat. 2) Hydrogen from steam reforming of methane using nuclear heat. The method used is differential economic analysis which focuses on evaluating the inherent advantages and disadvantages of the proposed technologies. Part II shows that the use of high temperature heat in production of hydrogen from coal is less attractive than the use of the same heat to generate electricity and split water into H2 and O2
Verhulst, Claire; Meneveau, Charles
2015-11-01
Vertical entrainment of mean kinetic energy is believed to be a limiting factor for power generation in very large wind farms, which operate in the turbulent atmospheric boundary layer and experience detrimental wake effects. A new approach, meant to increase vertical entrainment and aid wake recovery, is proposed and evaluated with a preliminary ``proof of concept'' test using Large Eddy Simulation (LES) with periodic boundary conditions to obtain realistic fully developed flow. In addition to the traditional actuator thrust force, a synthetic vertical force is applied at the turbine rotors to force high-speed flow downward and low-speed flow upward. The ratio of the vertical force and the thrust force, held constant within each case, ranges from 0 to 1 across six cases and is applied independently at each turbine. The proposed approach is found to increase the power extraction and mean kinetic energy entrainment significantly, by up to 95% when the vertical force is similar in magnitude to the thrust force. The effect of the forcing scheme on the mean velocity field is considered in detail. In addition, a quadrant analysis is performed to determine how the synthetic forcing changes the statistical characteristics of the mean kinetic energy entrainment within the wind farm. This work was supported by NSF grant 1243482 (the WINDINSPIRE project).
International Nuclear Information System (INIS)
Our aim is to prove existence and uniqueness of time-periodic strong solutions with finite kinetic energy for the Navier–Stokes equations in R3. For this, appropriate conditions are imposed on the external force, together with a smallness condition involving the viscosity of the fluid and the period of motion. We extend the method we have recently used to construct steady states with finite kinetic energy to the time-periodic case. First, existence and uniqueness of strong solutions with finite kinetic energy are established for a linearized version of the problem, using the Galerkin method and the Fourier transform in the space variables. Then, a strong solution with finite kinetic energy for the nonlinear problem is obtained by means of the contraction mapping principle. We also show that such a solution satisfies the energy equality and is unique within a class of weak solutions
Measurement of H- beam emittance in axial injection channel of DC-72 cyclotron
International Nuclear Information System (INIS)
A method of measuring the ion beam transversal emittance in the axial injection channel of DC-72 cyclotron is given. It is based on the gradient method using the standard rotating wire scanner for measurement of the transversal ion beam dimensions. This method was worked out for ion beam currents up to 1000 μA and allows one to reconstruct emittance with an accuracy about 30%. The method takes into account the ion beam self-charge, which is essential. It is not always a success to obtain an axial-symmetric ion beam in experiments. Therefore, a new experimental data processing method of measuring the transversal emittance for a non-axial-symmetric ion beam was suggested. The formulae for determination of the RMS dispersions of the ion beam dimensions in the rotation coordinate system by signals from the scanner wire are given. The measurements of the RMS emittances εx,y were carried out in the test stand of the injection channel of DC-72 cyclotron with the H- ion beam current of 180 μA and kinetic energy of ions of 16.82 keV. The results of the experimental data processing are adduced
Axial anomaly in nonrenormalizable theories
International Nuclear Information System (INIS)
The anomaly for the axial current in nonrenormalizable theories with electromagnetic coupling is considered. The spinor electrodynamics with Pauli term is examined in detail using the Feynman graph technique and the point-splitting method. The same finite value for the axial anomaly emerges. (author)
Rapalino, Otto; Smirniotopoulos, James G
2016-01-01
Extra-axial brain tumors are the most common adult intracranial neoplasms and encompass a broad spectrum of pathologic subtypes. Meningiomas are the most common extra-axial brain tumor (approximately one-third of all intracranial neoplasms) and typically present as slowly growing dural-based masses. Benign meningiomas are very common, and may occasionally be difficult to differentiate from more aggressive subtypes (i.e., atypical or malignant varieties) or other dural-based masses with more aggressive biologic behavior (e.g., hemangiopericytoma or dural-based metastases). Many neoplasms that typically affect the brain parenchyma (intra-axial), such as gliomas, may also present with primary or secondary extra-axial involvement. This chapter provides a general and concise overview of the common types of extra-axial tumors and their typical imaging features. PMID:27432671
Build Axial Gradient Field by Using Axial Magnetized Permanent Rings
Institute of Scientific and Technical Information of China (English)
无
2002-01-01
Axial magnetic field produced by an axial magnetized permanent ring was studied. For two permanent rings, if they are magnetized in the same directions, a nearly uniform axial field can be produced. If they are magnetized in opposite direction,an axial gradient magnetic field can be generated, with the field range changing from -B0 to B0. A permanent magnet with a high axial gradient field was fabricated, the measured results agree with the PANDIRA calculation very well. For wider usage,it is desirable for the field gradient to be changed. Some methods to produce the variable gradient field are presented. These kinds of axial gradient magnetic field can also be used as a beam focusing for linear accelerator if the periodic field can be produced along the beam trajectory. The axial magnetic field is something like a solenoid, large stray field will leak to the outside environment if no method is taken to control them. In this paper, one method is illustrated to shield off the outside leakage field.
Bode, Hans R.
2009-01-01
Morphogen gradients play an important role in pattern formation during early stages of embryonic development in many bilaterians. In an adult hydra, axial patterning processes are constantly active because of the tissue dynamics in the adult. These processes include an organizer region in the head, which continuously produces and transmits two signals that are distributed in gradients down the body column. One signal sets up and maintains the head activation gradient, which is a morphogenetic gradient. This gradient confers the capacity of head formation on tissue of the body column, which takes place during bud formation, hydra's mode of asexual reproduction, as well as during head regeneration following bisection of the animal anywhere along the body column. The other signal sets up the head inhibition gradient, which prevents head formation, thereby restricting bud formation to the lower part of the body column in an adult hydra. Little is known about the molecular basis of the two gradients. In contrast, the canonical Wnt pathway plays a central role in setting up and maintaining the head organizer. PMID:20066073
Bhattacharya, Ritthik; Stevens, Bjorn
2016-03-01
A two Turbulence Kinetic Energy (2TKE) model is developed to address the boundary layer "grey zone" problem. The model combines ideas from local and nonlocal models into a single energetically consistent framework. By applying the Reynolds averaging to the large eddy simulation (LES) equations that employ Deardorff's subgrid TKE, we arrive at a system of equations for the boundary layer quantities and two turbulence kinetic energies: one which encapsulates the TKE of large boundary-layer-scale eddies and another which represents the energy of eddies subgrid to the vertical grid size of a typical large-scale model. These two energies are linked via the turbulent cascade of energy from larger to smaller scales and are used to model the mixing in the boundary layer. The model is evaluated for three dry test cases and found to compare favorably to large eddy simulations. The usage of two TKEs for mixing helps reduce the dependency of the model on the vertical grid scale as well as on the free tropospheric stability and facilitates a smoother transition from convective to stable regimes. The usage of two TKEs representing two ranges of scales satisfies the prerequisite for modeling the boundary layer in the "grey zone": an idea that is explored further in a companion paper.
International Nuclear Information System (INIS)
Kinetic energy discrimination (KED) is one of the means to control cell-formed interferences in collision/reaction cell ICP-MS, and also a technique to reduce polyatomic ion interferences derived from the plasma or vacuum interface in collision cell ICP-MS. The operation of KED is accurately described to explain how spectral interferences from polyatomic ions are reduced by this technique. The cell is operated under non-thermal conditions to implement KED, where the hard sphere collision model is aptly employed to portray the transmission of ions colliding with the cell gas that they don't chemically react with. It is theoretically explained that the analyte atomic ions surmount the energy barrier placed downstream of the cell and the interfering polyatomic ions do not due to their lower kinetic energy than the atomic ions, resulting in polyatomic interference reduction. The intrinsic limitations of this technique are shown to lie in the statistical nature of collision processes, which causes the broadening of ion kinetic energy distribution that hinders efficient KED. The reaction cell operation with KED, where plasma-derived interferences are reduced by the reactive cell gas while cell-formed interferences are suppressed by the energy barrier, is also described in a quantitative manner. This review paper provides an in-depth understanding of KED in cell-based ICP-MS for analysts to make better use of it. - Highlights: • Hard sphere collision model was employed to describe the polyatomic ion interference reduction by KED. • The intrinsic limitations of KED lies in the statistical nature of collision processes. • It was shown that lighter collision gas is more effective than heavier one for polyatomic ion reduction by KED. • In non-thermal H2 reaction cell ICP-MS, KED does not contribute to the reduction of plasma-based interfering ions
Turbulence Kinetic Energy budget during the afternoon transition - Part 2: A simple TKE model
Nilsson, E.; Lothon, M.; Lohou, F.; Pardyjak, E.; Hartogensis, O.; Darbieu, C.
2015-11-01
A simple model for turbulence kinetic energy (TKE) and the TKE budget is presented for sheared convective atmospheric conditions based on observations from the Boundary Layer Late Afternoon and Sunset Turbulence (BLLAST) field campaign. It is based on an idealized mixed-layer approximation and a simplified near-surface TKE budget. In this model, the TKE is dependent on four budget terms (turbulent dissipation rate, buoyancy production, shear production and vertical transport of TKE) and only requires measurements of three input available (near-surface buoyancy flux, boundary layer depth and wind speed at one height in the surface layer). This simple model is shown to reproduce some of the observed variations between the different studied days in terms of near-surface TKE and its decay during the afternoon transition reasonably well. It is subsequently used to systematically study the effects of buoyancy and shear on TKE evolution using idealized constant and time-varying winds during the afternoon transition. From this, we conclude that many different TKE decay rates are possible under time-varying winds and that generalizing the decay with simple scaling laws for near-surface TKE of the form tα may be questionable. The model's errors result from the exclusion of processes such as elevated shear production and horizontal advection. The model also produces an overly rapid decay of shear production with height. However, the most influential budget terms governing near-surface TKE in the observed sheared convective boundary layers are included, while only second order factors are neglected. Comparison between modeled and averaged observed estimates of dissipation rate illustrate that the overall behavior of the model is often quite reasonable. Therefore, we use the model to discuss the low turbulence conditions that form first in the upper parts of the boundary layer during the afternoon transition and are only apparent later near the surface. This occurs as a
Solar Sailing Kinetic Energy Interceptor (KEI) Mission for Impacting/Deflecting Near-Earth Asteroids
Wie, Bong
2005-01-01
A solar sailing mission architecture, which requires a t least ten 160-m, 300-kg solar sail spacecraft with a characteristic acceleration of 0.5 mm/sqs, is proposed as a realistic near- term option for mitigating the threat posed by near-Earth asteroids (NEAs). Its mission feasibility is demonstrated for a fictional asteroid mitigation problem created by AIAA. This problem assumes that a 200-m asteroid, designated 2004WR, was detected on July 4, 2004, and that the expected impact will occur on January 14, 2015. The solar sailing phase of the proposed mission for the AIAA asteroid mitigation problem is comprised of the initial cruise phase from 1 AU t o 0.25 AU (1.5 years), the cranking orbit phase (3.5 years), and the retrograde orbit phase (1 year) prior to impacting the target asteroid at its perihelion (0.75 AU from the sun) on January 1, 2012. The proposed mission will require at least ten kinetic energy interceptor (KEI) solar sail spacecraft. Each KEI sailcraft consists of a 160- m, 150-kg solar sail and a 150-kg microsatellite impactor. The impactor is to be separated from a large solar sail prior to impacting the 200-m target asteroid at its perihelion. Each 150-kg microsatellite impactor, with a relative impact velocity of at least 70 km/s, will cause a conservatively estimated AV of 0.3 cm/s in the trajectory of the 200-m target asteroid, due largely to the impulsive effect of material ejected from the newly-formed crater. The deflection caused by a single impactor will increase the Earth-miss-distance by 0.45Re (where Re denotes the Earth radius of 6,378 km). Therefore, at least ten KEI sailcraft will be required for consecutive impacts, but probably without causing fragmentation, to increase the total Earth-miss-distance by 4.5Re. This miss-distance increase of 29,000 km is outside of a typical uncertainty/error of about 10,000 km in predicting the Earth-miss- distance. A conventional Delta I1 2925 launch vehicle is capable of injecting at least two KEI
DNS based analysis of liquid phase turbulence kinetic energy equation for bubbly two-phase flow
International Nuclear Information System (INIS)
While the modeling of turbulent single phase flows has already reached a certain level of maturity, models for the turbulence in bubble flows are still under development. The majority of models is based on the transport equation for liquid phase turbulence kinetic energy (kL) which is recast by extending the k-equation for single phase flow with empirical closure terms to account for the dispersed phase. In this paper we investigate bubble-induced liquid phase pseudo-turbulence by direct numerical simulations (DNS) based on the volume-of-fluid method. Simulations are performed for a regular array of ellipsoidal bubbles (gas hold up a 0.8%) and for a monodisperse swarm of 8 bubbles (a 6.4 %) rising in a plane vertical channel within an otherwise stagnant liquid. In the three bubble swarm simulations the liquid viscosity is varied by a factor of 10, resulting in a change of the bubble shape from ellipsoidal to spherical, a decrease of the average bubble rise velocity by a factor of 5 and a decrease of kL by a factor of 20. The DNS data are used to perform a detailed quantitative analysis of the analytical balance equation for kL. The evaluation comprises single-phase-like terms (diffusion, dissipation, production) as well as the interfacial term that only exists for two-phase flows. The general conclusion to be drawn for the considered bubbly flows is the prominent role of the interfacial term. Because the production term due to shear stresses is so low that it can be neglected, the interfacial term is the only one that feeds the liquid phase turbulence. The different closure terms in the analytical kL-equation are compared with respective closure assumptions for the modeled kL-equation implemented in two-phase k-l, k-e and ASM turbulence models. We find that - for the bubbly flows studied here - the conventional modelling of single-phase-like terms totally fails. Encouraging results are, however, obtained for modeling of the interfacial term. A detailed analysis of
Turbulence kinetic energy budget during the afternoon transition - Part 2: A simple TKE model
Nilsson, Erik; Lothon, Marie; Lohou, Fabienne; Pardyjak, Eric; Hartogensis, Oscar; Darbieu, Clara
2016-07-01
A simple model for turbulence kinetic energy (TKE) and the TKE budget is presented for sheared convective atmospheric conditions based on observations from the Boundary Layer Late Afternoon and Sunset Turbulence (BLLAST) field campaign. It is based on an idealized mixed-layer approximation and a simplified near-surface TKE budget. In this model, the TKE is dependent on four budget terms (turbulent dissipation rate, buoyancy production, shear production and vertical transport of TKE) and only requires measurements of three available inputs (near-surface buoyancy flux, boundary layer depth and wind speed at one height in the surface layer) to predict vertical profiles of TKE and TKE budget terms.This simple model is shown to reproduce some of the observed variations between the different studied days in terms of near-surface TKE and its decay during the afternoon transition reasonably well. It is subsequently used to systematically study the effects of buoyancy and shear on TKE evolution using idealized constant and time-varying winds during the afternoon transition. From this, we conclude that many different TKE decay rates are possible under time-varying winds and that generalizing the decay with simple scaling laws for near-surface TKE of the form tα may be questionable.The model's errors result from the exclusion of processes such as elevated shear production and horizontal advection. The model also produces an overly rapid decay of shear production with height. However, the most influential budget terms governing near-surface TKE in the observed sheared convective boundary layers are included, while only second-order factors are neglected. Comparison between modeled and averaged observed estimates of dissipation rate illustrates that the overall behavior of the model is often quite reasonable. Therefore, we use the model to discuss the low-turbulence conditions that form first in the upper parts of the boundary layer during the afternoon transition and are only
Signarbieux, C.; Simon, G.; Trochon, J.; Brisard, F.
1985-01-01
The performance of a back-to-back gridded ionization chamber containing an extremely thin fissile target has been investigated for studying the cold fragmentation phenomenon : primary fragment kinetic energy is measured with a resolution much better than 300 keV; mass separation is total and for each mass, a good charge separation is obtained. The evolution of the charge distribution as a function of the fragments' total kinetic energy is discussed for the mass-ratio 132/104.
Institute of Scientific and Technical Information of China (English)
2008-01-01
L-shell X-ray spectra of Mo surface induced by Xe25+ and Xe29+ were measured. The X-ray intensity was obtained in the kinetic energy range of the incident ions from 350 to 600 keV. The relationship of X-ray intensity with kinetic energy of the projec-tile and its charge state were studied,and the simple explanation was given.
International Nuclear Information System (INIS)
The fission of 210Po, produced by three different nuclear reactions (209Bi + p, 206Pb + α and 198Pt + 12C), has been studied in detail in order to establish the dependence of various scission-point properties on the excitation energy and angular-momentum distribution of the fissioning nucleus. Excitation energies of 31, 44 and 57 MeV were chosen so as to give reasonable fission cross-sections, while avoiding a large contribution from second chance fission. The experiments were conducted on a beam line of the Harwell Variable Energy Cyclotron. The mean-fragment total-kinetic-energy release was found to be dependent on the 210Po excitation energy and angular-momentum distribution. The variances of the total-kinetic energy and mass distributions were found to be a strongly dependent on excitation energy but not on angular momentum. The experimental results of this work were found to be in good agreement with the theoretical liquid-drop-model calculations of Nix and Swiatecki. (author)
Energy Technology Data Exchange (ETDEWEB)
Vlahostergios, Z. [Laboratory of Fluid Mechanics and Turbomachinery, Department of Mechanical Engineering, Aristotle University of Thessaloniki, Karamanli str., Thessaloniki 54124 (Greece); Yakinthos, K. [Laboratory of Fluid Mechanics and Turbomachinery, Department of Mechanical Engineering, Aristotle University of Thessaloniki, Karamanli str., Thessaloniki 54124 (Greece)], E-mail: kyros@eng.auth.gr; Goulas, A. [Laboratory of Fluid Mechanics and Turbomachinery, Department of Mechanical Engineering, Aristotle University of Thessaloniki, Karamanli str., Thessaloniki 54124 (Greece)
2009-08-15
We present an effort to model the separation-induced transition on a flat plate with a semi-circular leading edge, using a cubic non-linear eddy-viscosity model combined with the laminar kinetic energy. A non-linear model, compared to a linear one, has the advantage to resolve the anisotropic behavior of the Reynolds-stresses in the near-wall region and it provides a more accurate expression for the generation of turbulence in the transport equation of the turbulence kinetic energy. Although in its original formulation the model is not able to accurately predict the separation-induced transition, the inclusion of the laminar kinetic energy increases its accuracy. The adoption of the laminar kinetic energy by the non-linear model is presented in detail, together with some additional modifications required for the adaption of the laminar kinetic energy into the basic concepts of the non-linear eddy-viscosity model. The computational results using the proposed combined model are shown together with the ones obtained using an isotropic linear eddy-viscosity model, which adopts also the laminar kinetic energy concept and in comparison with the existing experimental data.
Characterization of Multiflux Axial Compressors
International Nuclear Information System (INIS)
In the present work the results of analytical models of performance are compared with experimental data acquired in the multi flux axial compressor test facility, built in The Pilcaniyeu Technological Complex for the SIGMA project.We describe the experimental circuit and the data of the dispersion inside the axial compressor obtained using a tracer gas through one of the annular inlets.The attained results can be used to validate the design code for the multi flux axial compressors and SIGMA industrial plant
Axial gap rotating electrical machine
Energy Technology Data Exchange (ETDEWEB)
None
2016-02-23
Direct drive rotating electrical machines with axial air gaps are disclosed. In these machines, a rotor ring and stator ring define an axial air gap between them. Sets of gap-maintaining rolling supports bear between the rotor ring and the stator ring at their peripheries to maintain the axial air gap. Also disclosed are wind turbines using these generators, and structures and methods for mounting direct drive rotating electrical generators to the hubs of wind turbines. In particular, the rotor ring of the generator may be carried directly by the hub of a wind turbine to rotate relative to a shaft without being mounted directly to the shaft.
Fathali, M.; Deshiri, M. Khoshnami
2016-04-01
The shearless mixing layer is generated from the interaction of two homogeneous isotropic turbulence (HIT) fields with different integral scales ℓ1 and ℓ2 and different turbulent kinetic energies E1 and E2. In this study, the sensitivity of temporal evolutions of two-dimensional, incompressible shearless mixing layers to the parametric variations of ℓ1/ℓ2 and E1/E2 is investigated. The sensitivity methodology is based on the nonintrusive approach; using direct numerical simulation and generalized polynomial chaos expansion. The analysis is carried out at Reℓ 1=90 for the high-energy HIT region and different integral length scale ratios 1 /4 ≤ℓ1/ℓ2≤4 and turbulent kinetic energy ratios 1 ≤E1/E2≤30 . It is found that the most influential parameter on the variability of the mixing layer evolution is the turbulent kinetic energy while variations of the integral length scale show a negligible influence on the flow field variability. A significant level of anisotropy and intermittency is observed in both large and small scales. In particular, it is found that large scales have higher levels of intermittency and sensitivity to the variations of ℓ1/ℓ2 and E1/E2 compared to the small scales. Reconstructed response surfaces of the flow field intermittency and the turbulent penetration depth show monotonic dependence on ℓ1/ℓ2 and E1/E2 . The mixing layer growth rate and the mixing efficiency both show sensitive dependence on the initial condition parameters. However, the probability density function of these quantities shows relatively small solution variations in response to the variations of the initial condition parameters.
Wang, Jun; Qiao, Zhiqiang; Yang, Yuntao; Shen, Jinpeng; Long, Zhang; Li, Zhaoqian; Cui, Xudong; Yang, Guangcheng
2016-01-01
The energy performance of solid energetic materials (Al, Mg, etc.) is typically restricted by a natural passivation layer and the diffusion-limited kinetics between the oxidizer and the metal. In this work, we use polytetrafluoroethylene (PTFE) as the fluorine carrier and the shielding layer to construct a new type of nano-Al based fuels. The PTFE shell not only prevents nano-Al layers from oxidation, but also assists in enhancing the reaction kinetics, greatly improving the stability and reactivity of fuels. An in situ chemical vapor deposition combined with the electrical explosion of wires (EEW) method is used to fabricate core-shell nanostructures. Studies show that by controlling the stoichiometric ratio of the precursors, the morphology of the PTFE shell and the energy performance can be easily tuned. The resultant composites exhibit superior energy output characters than that of their physically mixed Al/PTFE counterparts. This synthetic strategy might provide a general approach to prepare other high-energy fuels (Mg, Si). PMID:26612396
Camp, Elizabeth H.; Cal, Raúl Bayoán
2016-08-01
An array of model rotating wind turbines is compared experimentally to an array of static porous disks in order to quantify the similarities and differences in the mean kinetic energy transport within the wakes produced in these two cases. Stereo particle image velocimetry measurements are done in a wind tunnel bracketing the center turbine in the fourth row of a 4 ×3 array of model turbines. Equivalent sets of rotors and porous disks are created by matching their respective induction factors. The primary difference in the mean velocity components is found in the spanwise mean velocity component, which is as much as 190% different between the rotor and disk case. Horizontal averages of mean kinetic energy transport terms in the region where rotation is most important show percent differences in the range 3%-41%, which decrease to 1%-6% at streamwise coordinates where rotation is less important. Octant analysis is performed on the most significant term related to vertical mean kinetic energy flux u'v' ¯U . The average percent difference between corresponding octants is as much as 68% different in the near wake and as much as 17% different in the far wake. Furthermore, octant analysis elucidates the three-dimensional nature of sweeps and ejections in the near wake of the rotor case. Together, these results imply that a stationary porous disk adequately represents the mean kinetic energy transport of a rotor in the far wake where rotation is less important, while significant discrepancies exist at streamwise locations where rotation is a key phenomenon. This comparison has implications in the use of an actuator disk to model the wind turbine rotor in computational simulations specifically for studies where Reynolds stresses, turbulence intensity, or interactions with the atmosphere are of interest.
Wei, Hua-Rong; Lacey, Roy A
2015-01-01
Experimental results of the transverse momentum spectra of final-state light flavour particles produced in gold-gold (Au-Au), copper-copper (Cu-Cu), lead-lead (Pb-Pb), proton-lead (p-Pb), and proton-proton (p-p) collisions at various energies, measured by the PHENIX, STAR, ALICE, and CMS Collaborations, are described by the Tsallis-standard (Tsallis form of Fermi-Dirac or Bose-Einstein) distribution, Tsallis distribution, and two- or three-component standard distribution, in the framework of a multisource thermal model. The effective temperatures and real temperatures (kinetic freeze-out temperatures) of interacting system at the stage of kinetic freeze-out, and the radial flow velocities of final-state particles are successively extracted from the transverse momentum spectra by the three distributions which can be in fact regarded as three types of "thermometers" and "speedometers". The dependences of effective temperatures on particle mass and centrality, and the dependences of kinetic freeze-out temperatur...
Slawinski, J; Bonnefoy, A; Ontanon, G; Leveque, J M; Miller, C; Riquet, A; Chèze, L; Dumas, R
2010-05-28
The aim of the present study was to measure during a sprint start the joint angular velocity and the kinetic energy of the different segments in elite sprinters. This was performed using a 3D kinematic analysis of the whole body. Eight elite sprinters (10.30+/-0.14s 100 m time), equipped with 63 passive reflective markers, realised four maximal 10 m sprints start on an indoor track. An opto-electronic Motion Analysis system consisting of 12 digital cameras (250 Hz) was used to collect the 3D marker trajectories. During the pushing phase on the blocks, the 3D angular velocity vector and its norm were calculated for each joint. The kinetic energy of 16 segments of the lower and upper limbs and of the total body was calculated. The 3D kinematic analysis of the whole body demonstrated that joints such as shoulders, thoracic or hips did not reach their maximal angular velocity with a movement of flexion-extension, but with a combination of flexion-extension, abduction-adduction and internal-external rotation. The maximal kinetic energy of the total body was reached before clearing block (respectively, 537+/-59.3 J vs. 514.9+/-66.0 J; p< or =0.01). These results suggested that a better synchronization between the upper and lower limbs could increase the efficiency of pushing phase on the blocks. Besides, to understand low interindividual variances in the sprint start performance in elite athletes, a 3D complete body kinematic analysis shall be used. PMID:20226465
Directory of Open Access Journals (Sweden)
Karlsson J
2015-07-01
Full Text Available Johan Karlsson, Saba Atefyekta, Martin Andersson Department of Chemical and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden Abstract: The osseointegration capacity of bone-anchoring implants can be improved by the use of drugs that are administrated by an inbuilt drug delivery system. However, to attain superior control of drug delivery and to have the ability to administer drugs of varying size, including proteins, further material development of drug carriers is needed. Mesoporous materials have shown great potential in drug delivery applications to provide and maintain a drug concentration within the therapeutic window for the desired period of time. Moreover, drug delivery from coatings consisting of mesoporous titania has shown to be promising to improve healing of bone-anchoring implants. Here we report on how the delivery of an osteoporosis drug, alendronate, can be controlled by altering pore size and surface energy of mesoporous titania thin films. The pore size was varied from 3.4 nm to 7.2 nm by the use of different structure-directing templates and addition of a swelling agent. The surface energy was also altered by grafting dimethylsilane to the pore walls. The drug uptake and release profiles were monitored in situ using quartz crystal microbalance with dissipation (QCM-D and it was shown that both pore size and surface energy had a profound effect on both the adsorption and release kinetics of alendronate. The QCM-D data provided evidence that the drug delivery from mesoporous titania films is controlled by a binding–diffusion mechanism. The yielded knowledge of release kinetics is crucial in order to improve the in vivo tissue response associated to therapeutic treatments. Keywords: mesoporous titania, controlled drug delivery, release kinetics, alendronate, QCM-D
Poggi, D.; Katul, G. G.
2010-08-01
Inferring the vertical variation of the mean turbulent kinetic energy dissipation rate ( ɛ) inside dense canopies remains a basic research problem to be confronted. Using detailed laser Doppler anemometry (LDA) measurements collected within a densely arrayed rod canopy, traditional and newly proposed methods to infer ɛ profiles are compared. The traditional methods for estimating ɛ at a given layer include isotropic relationships applied to the viscous dissipation scales that are resolved by LDA measurements, higher order structure function methods, and residuals of the turbulent kinetic energy budget in which production and transport terms are all independently inferred. The newly proposed method extends earlier approaches based on zero-crossing statistics, which were shown to be promising in a number of laboratory flows. The extension to account for an arbitrary threshold (hereafter referred to as the level-crossing method) instead of zero-crossing minimizes the effects of instrument noise on the inferred ɛ. While none of the ɛ methods employed here can be titled as ‘measured’, these methods differ in their underlying assumptions and simplifications. Above the canopy, where a balance between production and dissipation rate of turbulent kinetic energy is expected, the agreement among all the methods is reasonably good. In the lower-to-middle layers of the canopy, all the methods agree except for those based on a structure-function inference of ɛ. This departure can be attributed to the lack of a well-defined inertial subrange in these layers. In the upper canopy layers, the disagreements between the methods are largest. Even the higher order structure-function methods disagree with each other when ɛ is inferred from third- and fifth-order moments. However, for all layers within the canopy, the proposed zero- and threshold-crossing methods agree well with estimates of ɛ derived from the isotropic relationship applied to the viscous dissipation range
High order magnetic optics for high dynamic range proton radiography at a kinetic energy of 800 MeV
Sjue, S. K. L.; Mariam, F. G.; Merrill, F. E.; Morris, C. L.; Saunders, A.
2016-01-01
Flash radiography with 800 MeV kinetic energy protons at Los Alamos National Laboratory is an important experimental tool for investigations of dynamic material behavior driven by high explosives or pulsed power. The extraction of quantitative information about density fields in a dynamic experiment from proton generated images requires a high fidelity model of the proton imaging process. It is shown that accurate calculations of the transmission through the magnetic lens system require terms beyond second order for protons far from the tune energy. The approach used integrates the correlated multiple Coulomb scattering distribution simultaneously over the collimator and the image plane. Comparison with a series of static calibration images demonstrates the model's accurate reproduction of both the transmission and blur over a wide range of tune energies in an inverse identity lens that consists of four quadrupole electromagnets.
High order magnetic optics for high dynamic range proton radiography at a kinetic energy of 800 MeV
Energy Technology Data Exchange (ETDEWEB)
Sjue, S. K. L., E-mail: sjue@lanl.gov; Mariam, F. G.; Merrill, F. E.; Morris, C. L.; Saunders, A. [Physics Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)
2016-01-15
Flash radiography with 800 MeV kinetic energy protons at Los Alamos National Laboratory is an important experimental tool for investigations of dynamic material behavior driven by high explosives or pulsed power. The extraction of quantitative information about density fields in a dynamic experiment from proton generated images requires a high fidelity model of the proton imaging process. It is shown that accurate calculations of the transmission through the magnetic lens system require terms beyond second order for protons far from the tune energy. The approach used integrates the correlated multiple Coulomb scattering distribution simultaneously over the collimator and the image plane. Comparison with a series of static calibration images demonstrates the model’s accurate reproduction of both the transmission and blur over a wide range of tune energies in an inverse identity lens that consists of four quadrupole electromagnets.
Variation of Kinetic Energy of Fragments in Fission of 235U with 0.006 - 20ev Neutrons
International Nuclear Information System (INIS)
Utilizing the LNF ONYal neutron spectrometer working in the energy range between 0.006 and 20 eV, the variation in fragments' kinetic energy (EK) was studied, applying the method of relative yields (W) measurements, in the thermal neutron region and at 11 resonances of 235U. It was found that the resonances at 0.29, 2.04, 3.14, 4.84, and 7.09 eV can be sorted in a group of resonances with small values of W and EK . The resonances at 1.14, 3.60, 6.40, 8.78, 12.4, and 19.3 eV form a group with big values of W and EK. Comparison of W with radiochemical data on fragments' yield at thermal and resonance region of 235U showed that EK is larger at more asymmetrical fission. From the values W ( I ) and W(II) for the two groups of resonances, the change in the average kinetic energy of fragments 2ΔEK = 0.74 ± 0. 32 MeV was determined. (author)
Nyakuma, Bemgba Bevan
2015-12-01
This study seeks to characterize the thermochemical fuel properties of melon seed husk (MSH) as a potential biomass feedstock for clean energy and power generation. It examined the ultimate analysis, proximate analysis, FTIR spectroscopy and thermal decomposition of MSH. Thermogravimetric (TG) analysis was examined at 5, 10, 20 °C/min from 30-800 °C under nitrogen atmosphere. Subsequently, the Distributed Activation Energy Model (DAEM) was applied to determine the activation energy, E, and frequency factor, A. The results revealed that thermal decomposition of MSH occurs in three (3) stages; drying (30-150 °C), devolatization (150-400 °C) and char degradation (400-800 °C). Kinetic analysis revealed that the E values fluctuated from 145.44-300 kJ/mol (Average E = 193 kJ/mol) while A ranged from 2.64 × 1010 to 9.18 × 1020 min-1 (Average E = 9.18 × 1019 min-1) highlighting the complexity of MSH pyrolysis. The fuel characterization and kinetics of MSH showed it is an environmentally friendly solid biofuel for future thermal biomass conversion.
Directory of Open Access Journals (Sweden)
S. W. H. Cowley
2006-03-01
Full Text Available Recent spectroscopic observations of Jupiter's "main oval" auroras indicate that the primary auroral electron beam is routinely accelerated to energies of ~100 keV, and sometimes to several hundred keV, thus approaching the relativistic regime. This suggests the need to re-examine the classic non-relativistic theory of auroral electron acceleration by field-aligned electric fields first derived by Knight (1973, and to extend it to cover relativistic situations. In this paper we examine this problem for the case in which the source population is an isotropic Maxwellian, as also assumed by Knight, and derive exact analytic expressions for the field-aligned current density (number flux and kinetic energy flux of the accelerated population, for arbitrary initial electron temperature, acceleration potential, and field strength beneath the acceleration region. We examine the limiting behaviours of these expressions, their regimes of validity, and their implications for auroral acceleration in planetary magnetospheres (and like astrophysical systems. In particular, we show that for relativistic accelerating potentials, the current density increases as the square of the minimum potential, rather than linearly as in the non-relativistic regime, while the kinetic energy flux then increases as the cube of the potential, rather than as the square.
Albite feldspar dissolution kinetics as a function of the Gibbs free energy at high pCO_2
Hellmann, Roland; Tisserand, Delphine; Renard, François
2008-01-01
We are currently measuring the dissolution kinetics of albite feldspar at 100 deg C in the presence of high levels of dissolved CO_2 (pCO_2 = 9 MPa) as a function of the saturation state of the feldspar (Gibbs free energy of reaction, \\Delta G). The experiments are conducted using a flow through reactor, thereby allowing the dissolution reactions to occur at a fixed pH and at constant, but variable saturation states. Preliminary results indicate that at far-from-equilibrium conditions, the dissolution kinetics of albite are defined by a rate plateau, with R \\approx 5.0 x 10^{-10} mol m^{-2} s^{-1} at -70 -40 kJ mol^{-1}, the rates decrease sharply, revealing a strong inverse relation between the dissolution rate and free energy. Based on the experiments carried out to date, the dissolution rate-free energy data correspond to a highly non-linear and sigmoidal relation, in accord with recent studies.
Ko, Hyunseok; Szlufarska, Izabela; Morgan, Dane
2016-01-01
The diffusion of silver (Ag) impurities in high energy grain boundaries (HEGBs) of cubic (3C) silicon carbide (SiC) is studied using an ab initio based kinetic Monte Carlo (kMC) model. This study assesses the hypothesis that the HEGB diffusion is responsible for Ag release in Tristructural-Isotropic fuel particles, and provides a specific example to increase understanding of impurity diffusion in highly disordered grain boundaries. The HEGB environment was modeled by an amorphous SiC. The structure and stability of Ag defects were calculated using density functional theory code. The defect energetics suggested that the fastest diffusion takes place via an interstitial mechanism in a-SiC. The formation energy of Ag interstitials and the kinetic resolved activation energies between them were well approximated with Gaussian distributions that were then sampled in the kMC. The diffusion of Ag was simulated with the effective medium model using kMC. At 1200-1600C, Ag in a HEGB is predicted to exhibit an Arrhenius ...
Evidence of two-length-scale kinetics of R-phase transformation by high-energy X-ray diffraction
International Nuclear Information System (INIS)
The cubic-to-rhombohedral (C-R) phase transition in an AuCd shape memory alloy was investigated by in situ high-energy X-ray diffraction. We present the first direct experimental evidence of two-length-scale phase transition kinetics in this alloy system. It was further found that aging in the R-phase leads to two-way memory 'loss', characterized by the reselection of new variants. We attributed this two-way memory 'loss' to the internal stresses caused by the defects formed in the off-equilibrium state of the studied AuCd system.
International Nuclear Information System (INIS)
Full text: Systematic dependence of mass discrimination on ICP operating parameters was investigated for two MCICPMS instruments, a Nu Plasma HR and a Nu Plasma 1700, which differ both in acceleration voltage and spectrometer geometry. Gas temperature variations were determined by absolute pressure measurements at the vacuum interface. Their influence on ion kinetic energy as monitored by means of a retardation filter fitted in front of an ion counting detector will be discussed and compared to effects resulting from variations in acceleration voltage. (author)
Geißler, C.; Nadrowski, K.; Kühn, P.; Baruffol, M.; Lang, A. C.; von Oheimb, G.; Härdtle, W.; Scholten, T.
2012-04-01
To combat soil erosion is a prominent and most important ecosystem service of forests. Yet, little is known about the mechanistic relation of this ecosystem service to biodiversity. We hypothesize that the underlying processes in forests can be explained by (i) mechanisms that alter rainfall properties and (ii) those that change forest floor properties. The present study concentrates on the alteration of rainfall properties by vegetation canopies in a subtropical forest ecosystem in SE-China. The research approach consists of investigations in established forest stands complemented by measurements in a plantation-like experiment. On the level of whole forest stands we relate forest succession, specific species, forest stand variables and species richness as a measure of biodiversity to throughfall kinetic energy (KE) (plot size=900m2). Effects of plant architectural traits, species identity and stand density on throughfall KE were studied more in detail on a smaller spatial scale (plot size=1m2) and related to changes in throughfall KE. On the forest stand level we could identify effects of tree canopy structure (height, leaf area index), diversity (rarefied species number) and functional trait identity (proportion of needle leafed species). Throughfall KE increases with canopy height, biodiversity and an interaction between canopy height and rainfall amount where both factors reinforce each other. It decreases with increasing proportion of needle leafed species within a plot and an increasing LAI. In subtropical broad-leaved forests throughfall KE is largely controlled by forest structure, traits and the number of the species present in the canopy. High coverage and a low total height keeps throughfall KE low in younger plots whereas canopy gaps and a higher total height enlarge the values of throughfall KE in older plots. The variability of throughfall KE is controlled by rainfall intensity and biodiversity which counteract against each other. The variability of
International Nuclear Information System (INIS)
The torsional energy levels of CH3OH+, CH3OD+, and CD3OD+ have been determined for the first time using one-photon zero kinetic energy photoelectron spectroscopy. The adiabatic ionization energies for CH3OH, CH3OD, and CD3OD are determined as 10.8396, 10.8455, and 10.8732 eV with uncertainties of 0.0005 eV, respectively. Theoretical calculations have also been performed to obtain the torsional energy levels for the three isotopologues using a one-dimensional model with approximate zero-point energy corrections of the torsional potential energy curves. The calculated values are in good agreement with the experimental data. The barrier height of the torsional potential energy without zero-point energy correction was calculated as 157 cm−1, which is about half of that of the neutral (340 cm−1). The calculations showed that the cation has eclipsed conformation at the energy minimum and staggered one at the saddle point, which is the opposite of what is observed in the neutral molecule. The fundamental C–O stretch vibrational energy level for CD3OD+ has also been determined. The energy levels for the combinational excitation of the torsional vibration and the fundamental C–O stretch vibration indicate a strong torsion-vibration coupling
Nuclear Axial Currents in Chiral Effective Field Theory
Baroni, A.; Girlanda, L.; Pastore, S.; Schiavilla, R.; Viviani, M
2015-01-01
Two-nucleon axial charge and current operators are derived in chiral effective field theory up to one loop. The derivation is based on time-ordered perturbation theory, and accounts for cancellations between the contributions of irreducible diagrams and the contributions due to non-static corrections from energy denominators of reducible diagrams. Ultraviolet divergencies associated with the loop corrections are isolated in dimensional regularization. The resulting axial current is finite and...
Computer simulation of energy profiles in a plasma focus device
International Nuclear Information System (INIS)
The study of the plasma focus dynamics has been treated to include the distribution profiles of kinetic energy, electrical energy and the power input in the axial and the pinch off phase. The snowplow model equations and the pinch phase equations for plasma motion in one dimension and the equation of energies have been simulated on computer. The distribution of the energies show strong dependence on the ratio of the periodic time of the external circuit to the transit time of the current sheath motion in the axial phase
International Nuclear Information System (INIS)
For the temperature fields in rod clads of experimental assemblies a good agreement have been got with use of prior calculations by subchannel code COBRA-IV-I, from results of which an additional information about δt/δX3 distribution was taken. The method of definition the local fields of velocity, turbulent kinetic energy, temperature and eddy diffusivities for one-phase axial stabilized fluids in arbitrary formed rod bundle assemblies with invariable upward geometry was developed. According to this model the AGURA code was worked out to calculate local thermal hydraulic problems in combination with temperature fields in fuel rods and constructive elements of fuel assemblies. The method does not use any prior geometric scales and is based only on invariant local flow parameters: turbulent kinetic energy, velocity field deformation tensor and specific work of inner friction. Verification of this method by available experimental data showed a good agreement of calculation data and findings of velocity and t.k.e. fields, when the secondary flows have not a substantial influence to a balance of axial momentum and turbulent kinetic energy. (author)
International Nuclear Information System (INIS)
Effect of artificial blood, FC 43 (Perfluorochemicals) on the kinetics of high-energy phosphate in the myocardium was evaluated by 31P-NMR which permits a continuous and non-invasive assessment of in vivo phosphorus compounds. Cardiac perfusion was carried out on a excised rat heart with a Krebs-Henseleit modified solution and FC 43 alternately. Under the normal condition, ischemic condition, and at second perfusion amounts of intramyocardial creatine phosphoric acid, ATP, and inorganic phosphorus were determined by 31P-NMR. Coronary flow was simultaneously estimated. The ischemic state due to interruption of perfusion resulted in a decrease in creatine phosphoric acid, which was associated with an increase in inorganic phosphorus and intracellular acidosis. No change of ATP amount was observed under ischemic state. With resumption of perfusion, the levels of creatine phosphoric acid and inorganic phosphorus rapidly returned to the normal. In the group of FC 43, coronary flow was 2.68 ml/min/g of the heart weight, about 1/2 of that of the Krebs-Henseleit group (5.68 ml/min/g of the heart weight). In controls, there was no difference between the two groups concerning creatine phosphoric acid level and recovery of creatine phospohric acid level after ischemia. These results showed that FC 43 supplies sufficient oxygen, and has no effect on the kinetics of energy in the myocardium. (Ueda, J.)
Fundamentally excited ﬂow past a surface-mounted rib. Part II: Kinetic energy budget details
Indian Academy of Sciences (India)
P K Panigrahi
2001-10-01
This paper presents the detailed turbulent kinetic energy budget and higher order statistics of ﬂow behind a surface-mounted rib with and without superimposed acoustic excitation. Pattern recognition technique is used to determine the large-scale structure magnitude. It is observed that most of the turbulence contributions after the reattachment region are from the large-scale structures contrary to the belief that mostly random turbulent structures are present after reattachment. The dissipation is not a small-scale phenomena only. It may result due to the interaction between large-scale structures. From the results of higher order moments, the outer edge of the shear layer is observed to be non-Gaussian in nature with signiﬁcant deviation from the Gaussian skewness and ﬂatness value. The kinetic energy budget results show positive intermodal production in the outer edge of the shear layer indicating the presence of back scattering. The non-Gaussian velocity distribution, ejection motions and back-scattering present in the outer shear layer may be conjectured to be correlated with each other.
Energy Technology Data Exchange (ETDEWEB)
Martinez, G.; Barreau, G.; Sicre, A.; Doan, T.P.; Audouard, P.; Leroux, B. (CEA Centre d' Etudes Nucleaires de Bordeaux-Gradignan, 33 - Gradignan (France)); Arafa, W.; Brissot, R.; Bocquet, J.P. (Grenoble-1 Univ., 38 (France). Inst. des Sciences Nucleaires); Faust, H. (Institut Max von Laue - Paul Langevin, 38 - Grenoble (France)); Koczon, P.; Mutterer, M. (Technische Hochschule Darmstadt (Germany, F.R.). Inst. fuer Kernphysik); Goennenwein, F. (Tuebingen Univ. (Germany, F.R.). Physikalisches Inst.); Asghar, M. (Universite des Sciences et de la Technologie Houari Boumediene, Algiers (Algeria). Inst. de Physique); Quade, U.; Rudolph, K. (Muenchen Univ. (Germany, F.R.)); Engelhardt, D. (Karlsruhe Univ. (T.H.) (Germany, F.R.)); Piasecki, E. (Warsaw Univ. (Poland))
1990-09-03
The recoil mass separator LOHENGRIN of the Laue-Langevin Institute Grenoble has been used to measure for the first time, the yields of light fission fragments from the fissioning system: {sub 93}{sup 239}Np; this odd-Z nucleus is formed after double thermal neutron capture in a {sub 93}{sup 237}Np target. The mass distributions were measured for different kinetic energies between 92 and 115.5 MeV, but the nuclear charge distributions were determined only up to 112 MeV. These distributions are compared to the distributions obtained for the even-even system {sub 94}{sup 240}Pu. At high kinetic energy, the mass distribution shows a prominent peak around mass number A{sub L}=106. These cold fragmentations are discussed in terms of a calculation based on a scission point model extrapolated to the cold fission case. As expected for an odd-Z fissioning nucleus, the nuclear charge distributions do not reveal any odd-even effect. The global neutron odd-even effect is found to be (8.1{plus minus}1.5)%. A simple model has been used to show that most of the neutron odd-even effect results from prompt neutron evaporation from the fragments. (orig.).
Pyrolysis Characteristics and Kinetics of Phoenix Tree Residues as a Potential Energy
Li, H.; X.-H. Li; L. Liu; K.-Q. Li; X.-H. Wang
2015-01-01
By using a thermogravimetric analyser under argon atmosphere, the pyrolysis process and the kinetic model of phoenix tree residues (the little stem, middle stem, and leaf) at a 30 °C min−1 heating rate and the phoenix tree mix at three different heating rates (10 °C min−1, 30 °C min−1, and 50 °C min−1) were examined. The catalyst and the co-pyrolysis samples were at a 30 °C min−1 heating rate. The catalysts were Na2CO3, ZnCl2 and CaO in a mass fraction of 5 %. The experimental results reveale...
Liang, Z.; Bédard-Tremblay, L.; Bauwens, L
2007-01-01
The structure of the steady planar detonation wave is analyzed for three-step chain-branching kinetics consistent with hydrogen–air chemistry. The initiation and chain-branching steps are described by an Arrhenius rate. Both are thermally neutral, so that heat release is due to termination. The initiation rate is typically very low and very stiff. As a result, a small fraction of the reactant is consumed in the initiation region, which is very long but ends in an exponential chain-branching e...
Marino, Raffaele; Rosenberg, Duane; Herbert, Corentin; Pouquet, Annick
2015-11-01
The interplay between waves and eddies in stably stratified rotating flows is investigated by means of world-class direct numerical simulations using up to 30723 grid points. Strikingly, we find that the shift from vortex- to wave-dominated dynamics occurs at a wave number k R which does not depend on the Reynolds number, suggesting that the partition of energy between wave and vortical modes is not sensitive to the development of turbulence at the smaller scales. We also show that k R is comparable to the wave number at which exchanges between kinetic and potential modes stabilize at close to equipartition, emphasizing the role of potential energy, as conjectured in the atmosphere and the oceans. Moreover, k R varies as the inverse of the Froude number as explained by the scaling prediction proposed, consistently with recent observations and modeling of the Mesosphere-Lower Thermosphere and of the ocean.
Marino, Raffaele; Herbert, Corentin; Pouquet, Annick
2015-01-01
The interplay between waves and eddies in stably stratified rotating flows is investigated by means of world-class direct numerical simulations using up to $3072^3$ grid points. Strikingly, we find that the shift from vortex to wave dominated dynamics occurs at a wavenumber $k_R$ which does not depend on Reynolds number, suggesting that partition of energy between wave and vortical modes is not sensitive to the development of turbulence at the smaller scales. We also show that $k_R$ is comparable to the wavenumber at which exchanges between kinetic and potential modes stabilize at close to equipartition, emphasizing the role of potential energy, as conjectured in the atmosphere and the oceans. Moreover, $k_R$ varies as the inverse of the Froude number as explained by the scaling prediction proposed, consistent with recent observations and modeling of the Mesosphere-Lower Thermosphere and of the ocean.
Antonov, Ivan O.; Barker, Beau J.; Heaven, Michael C.
2011-01-01
The ground electronic state of BeOBe+ was probed using the pulsed-field ionization zero electron kinetic energy photoelectron technique. Spectra were rotationally resolved and transitions to the zero-point level, the symmetric stretch fundamental and first two bending vibrational levels were observed. The rotational state symmetry selection rules confirm that the ground electronic state of the cation is 2Σg+. Detachment of an electron from the HOMO of neutral BeOBe results in little change in the vibrational or rotational constants, indicating that this orbital is nonbonding in nature. The ionization energy of BeOBe [65480(4) cm-1] was refined over previous measurements. Results from recent theoretical calculations for BeOBe+ (multireference configuration interaction) were found to be in good agreement with the experimental data.
质点动能定理的推导及应用%Derivation and application of the kinetic energy theorem of particle
Institute of Scientific and Technical Information of China (English)
刘雪梅; 张金锋
2013-01-01
The kinetic energy theorem of particle is derived by the equation of particle motion and Newton's second law.The two specific examples are solved by using the kinetic energy theorem of particle,Newton's second law and work-energy theorem,which reflects the application of the kinetic energy theorem of particle is more easy and more convenient.%利用牛顿第二定律及质点运动方程推导出质点动能定理形式，对两个具体实例分别运用质点动能定理、牛顿定律、功能原理进行求解，从而体现应用质点动能定律计算更加简单、方便。
CFD Simulation and Optimization of Very Low Head Axial Flow Turbine Runner
Directory of Open Access Journals (Sweden)
Yohannis Mitiku Tobo
2015-10-01
Full Text Available The main objective of this work is Computational Fluid Dynamics (CFD modelling, simulation and optimization of very low head axial flow turbine runner to be used to drive a centrifugal pump of turbine-driven pump. The ultimate goal of the optimization is to produce a power of 1kW at head less than 1m from flowing river to drive centrifugal pump using mechanical coupling (speed multiplier gear directly. Flow rate, blade numbers, turbine rotational speed, inlet angle are parameters used in CFD modeling, simulation and design optimization of the turbine runner. The computed results show that power developed by a turbine runner increases with increasing flow rate. Pressure inside the turbine runner increases with flow rate but, runner efficiency increases for some flow rate and almost constant thereafter. Efficiency and power developed by a runner drops quickly if turbine speed increases due to higher pressure losses and conversion of pressure energy to kinetic energy inside the runner. Increasing blade number increases power developed but, efficiency does not increase always. Efficiency increases for some blade number and drops down due to the fact that change in direction of the relative flow vector at the runner exit, which decreases the net rotational momentum and increases the axial flow velocity.
Tao, Yang; Zhang, Zhihang; Sun, Da-Wen
2014-07-01
The effects of acoustic energy density (6.8-47.4 W/L) and temperature (20-50 °C) on the extraction yields of total phenolics and tartaric esters during ultrasound-assisted extraction from grape marc were investigated in this study. The ultrasound treatment was performed in a 25-kHz ultrasound bath system and the 50% aqueous ethanol was used as the solvent. The initial extraction rate and final extraction yield increased with the increase of acoustic energy density and temperature. The two site kinetic model was used to simulate the kinetics of extraction process and the diffusion model based on the Fick's second law was employed to determine the effective diffusion coefficient of phenolics in grape marc. Both models gave satisfactory quality of data fit. The diffusion process was divided into one fast stage and one slow stage and the diffusion coefficients in both stages were calculated. Within the current experimental range, the diffusion coefficients of total phenolics and tartaric esters for both diffusion stages increased with acoustic energy density. Meanwhile, the rise of temperature also resulted in the increase of diffusion coefficients of phenolics except the diffusion coefficient of total phenolics in the fast stage, the value of which being the highest at 40 °C. Moreover, an empirical equation was suggested to correlate the effective diffusion coefficient of phenolics in grape marc with acoustic energy density and temperature. In addition, the performance comparison of ultrasound-assisted extraction and convention methods demonstrates that ultrasound is an effective and promising technology to extract bioactive substances from grape marc. PMID:24613646
Xu, Tong; Ducote, Justin L.; Wong, Jerry T.; Molloi, Sabee
2011-02-01
Dual-energy chest radiography has the potential to provide better diagnosis of lung disease by removing the bone signal from the image. Dynamic dual-energy radiography is now possible with the introduction of digital flat-panel detectors. The purpose of this study is to evaluate the feasibility of using dynamic dual-energy chest radiography for functional lung imaging and tumor motion assessment. The dual-energy system used in this study can acquire up to 15 frames of dual-energy images per second. A swine animal model was mechanically ventilated and imaged using the dual-energy system. Sequences of soft-tissue images were obtained using dual-energy subtraction. Time subtracted soft-tissue images were shown to be able to provide information on regional ventilation. Motion tracking of a lung anatomic feature (a branch of pulmonary artery) was performed based on an image cross-correlation algorithm. The tracking precision was found to be better than 1 mm. An adaptive correlation model was established between the above tracked motion and an external surrogate signal (temperature within the tracheal tube). This model is used to predict lung feature motion using the continuous surrogate signal and low frame rate dual-energy images (0.1-3.0 frames per second). The average RMS error of the prediction was (1.1 ± 0.3) mm. The dynamic dual energy was shown to be potentially useful for lung functional imaging such as regional ventilation and kinetic studies. It can also be used for lung tumor motion assessment and prediction during radiation therapy.
Energy Technology Data Exchange (ETDEWEB)
Xu Tong [Department of Physics, Carleton University, 1125 Colonel By Drive, Ottawa, ON, K1S5B6 (Canada); Ducote, Justin L; Wong, Jerry T; Molloi, Sabee, E-mail: txu@physics.carleton.ca [Department of Radiological Sciences, University of California, Irvine, CA 92697 (United States)
2011-02-21
Dual-energy chest radiography has the potential to provide better diagnosis of lung disease by removing the bone signal from the image. Dynamic dual-energy radiography is now possible with the introduction of digital flat-panel detectors. The purpose of this study is to evaluate the feasibility of using dynamic dual-energy chest radiography for functional lung imaging and tumor motion assessment. The dual-energy system used in this study can acquire up to 15 frames of dual-energy images per second. A swine animal model was mechanically ventilated and imaged using the dual-energy system. Sequences of soft-tissue images were obtained using dual-energy subtraction. Time subtracted soft-tissue images were shown to be able to provide information on regional ventilation. Motion tracking of a lung anatomic feature (a branch of pulmonary artery) was performed based on an image cross-correlation algorithm. The tracking precision was found to be better than 1 mm. An adaptive correlation model was established between the above tracked motion and an external surrogate signal (temperature within the tracheal tube). This model is used to predict lung feature motion using the continuous surrogate signal and low frame rate dual-energy images (0.1-3.0 frames per second). The average RMS error of the prediction was (1.1 {+-} 0.3) mm. The dynamic dual energy was shown to be potentially useful for lung functional imaging such as regional ventilation and kinetic studies. It can also be used for lung tumor motion assessment and prediction during radiation therapy.
International Nuclear Information System (INIS)
Dual-energy chest radiography has the potential to provide better diagnosis of lung disease by removing the bone signal from the image. Dynamic dual-energy radiography is now possible with the introduction of digital flat-panel detectors. The purpose of this study is to evaluate the feasibility of using dynamic dual-energy chest radiography for functional lung imaging and tumor motion assessment. The dual-energy system used in this study can acquire up to 15 frames of dual-energy images per second. A swine animal model was mechanically ventilated and imaged using the dual-energy system. Sequences of soft-tissue images were obtained using dual-energy subtraction. Time subtracted soft-tissue images were shown to be able to provide information on regional ventilation. Motion tracking of a lung anatomic feature (a branch of pulmonary artery) was performed based on an image cross-correlation algorithm. The tracking precision was found to be better than 1 mm. An adaptive correlation model was established between the above tracked motion and an external surrogate signal (temperature within the tracheal tube). This model is used to predict lung feature motion using the continuous surrogate signal and low frame rate dual-energy images (0.1-3.0 frames per second). The average RMS error of the prediction was (1.1 ± 0.3) mm. The dynamic dual energy was shown to be potentially useful for lung functional imaging such as regional ventilation and kinetic studies. It can also be used for lung tumor motion assessment and prediction during radiation therapy.
PFI-ZEKE (Pulsed Field Ionization-Zero Electron Kinetic Energy) para el estudio de iones
Castaño, F.; Fernández, J. A.; Basterretxea, A. Longarte. F.; Sánchez Rayo, M. N.; Martínez, R.
Entre las áreas hacia donde ha evolucionado la Química en los últimos años están los estudios de sistemas con especies reactivas de alta energía y los dominados por fuerzas intermoleculares débiles, con energías de unas pocas kcal/mol. En efecto, el estudio de las propiedades de los iones, comenzando por su relación con la molécula neutra de la que procede, la energía de ionización, los estados vibracionales y rotacionales, energías de enlace de Van der Waals entre el ión y una amplia variedad de otras moléculas, sus confórmeros o isómeros y sus reacciones o semi-reacciones químicas están en la raíz de la necesidad de la espectroscopía conocida como PFI-ZEKE, Pulsed Field Ionization-Zero Electron Kinetic Energy. Entre las aplicaciones que requieren estos conocimientos se encuentran la generación de plasmas para la fabricación de semiconductores, memorias magnéticas, etc, así como los sistemas astrofísicos, la ionosfera terrestre, etc. La espectroscopía ZEKE es una evolución de las de fluorescencia inducida por láser, LIF, ionización multifotónica acrecentada por resonancia, REMPI, con uno y dos colores y acoplada a un sistema de tiempo de vuelo, REMPI-TOF-MS, y las espectroscopías de doble resonancia IR-UV y UV-UV. Sus espectros y la ayuda de cálculos ab inicio permite determinar las energías de enlace de complejos de van der Waals en estados fundamental y excitados, identificar confórmeros e isómeros, obtener energías de ionización experimentales aproximadas (100 cm-1) y otras variables de interés. Al igual que con LIF, REMPI y dobles resonancias, es posible utilizar muestras gaseosas, pero los espectros están muy saturados de bandas y su interpretación es difícil o imposible. Se evitan estas dificultades estudiando las moléculas o complejos en expansiones supersónicas, donde la T de los grados de libertad solo alcanzan unos pocos K. Para realizar experimentos de ZEKE hay que utilizar una propiedad recientemente
Mass Yields and Average Total Kinetic Energy Release in Fission for 235U, 238U, and 239Pu
Duke, Dana
2015-10-01
Mass yield distributions and average total kinetic energy (TKE) in neutron induced fission of 235U, 238U, and 239Pu targets were measured with a gridded ionization chamber. Despite decades of fission research, our understanding of how fragment mass yields and TKE depend on incident neutron energy is limited, especially at higher energies (above 5-10 MeV). Improved accuracy in these quantities is important for nuclear technology as it enhances our simulation capabilities and increases the confidence in diagnostic tools. The data can also guide and validate theoretical fission models where the correlation between the fragment mass and TKE is of particular value for constraining models. The Los Alamos Neutron Science Center - Weapons Neutron Research (LANSCE - WNR) provides a neutron beam with energies from thermal to hundreds of MeV, well-suited for filling in the gaps in existing data and exploring fission behavior in the fast neutron region. The results of the studies on target nuclei 235U, 238U, and 239Pu will be presented with a focus on exploring data trends as a function of neutron energy from thermal through 30 MeV. Results indicate clear evidence of structure due to multi-chance fission in the TKE . LA-UR-15-24761.
Energy Technology Data Exchange (ETDEWEB)
Devahastin, Sakamon; Pitaksuriyarat, Saovakhon [Department of Food Engineering, King Mongkut' s University of Technology Thonburi, 91 Pracha u-tid Road, Bangkok 10140 (Thailand)
2006-10-15
The present study aimed at investigating the feasibility of using a latent heat storage (LHS) with paraffin wax as a phase change material (PCM) to store excess solar energy and release it when the energy availability is inadequate or not available. First, attention was given on the heat transfer characteristics of the PCM during the charge and discharge periods of the LHS. The effects of inlet hot air temperature in the range of 70-90{sup o}C and inlet air velocities of 1 and 2ms{sup -1} on the charge time were determined, while during the discharge period only the effect of inlet ambient air velocity was considered. The effect of the use of LHS on the drying kinetics of sweet potato and the ability of the LHS to conserve energy during drying of sweet potato were also determined. It was found that the drying rate of sweet potato increased with a decrease of the inlet ambient air velocity. The amount of the energy extractable from the LHS was 1920 and 1386kJminkg{sup -1} and the energy savings was 40% and 34% when using an inlet ambient air velocity of 1 and 2ms{sup -1}, respectively. (author)
Vectorial versus axial goldstone bosons
International Nuclear Information System (INIS)
The Yukawa interactions of fermions with Goldstone bosons are given in closed form for an arbitrary renormalizable field theory to all orders of perturbation theory or for a general effective Lagrangian. Although the diagonal couplings are always pseudoscalar there is an important difference between spontaneously broken vector and axial-vector global symmetries. Compared to the axial case, the diagonal douplings of 'vectorial' Goldstone bosons to charged fermions are suppressed by mixing angles or appear only via radiative corrections involving gauge fields. This general result may be relevant for the problem of flavour symmetry breaking in composite models. (Author)
Simulation of an Axial Vircator
Tikhomirov, V V
2013-01-01
An algorithm of particle-in-cell simulations is described and tested to aid further the actual design of simple vircators working on axially symmetric modes. The methods of correction of the numerical solution, have been chosen and jointly tested, allow the stable simulation of the fast nonlinear multiflow dynamics of virtual cathode formation and evolution, as well as the fields generated by the virtual cathode. The selected combination of the correction methods can be straightforwardly generalized to the case of axially nonsymmetric modes, while the parameters of these correction methods can be widely used to improve an agreement between the simulation predictions and the experimental data.
International Nuclear Information System (INIS)
A double Frisch gridded ionization chamber has been used for the measurements. For both fission fragments the mass, kinetic energy and emission angle is found. Data have been measured at different neutron energies, Esub(n), ranging from thermal to 6.0 MeV in steps of 0.5 MeV. The measured angular anisotropies will be shown. A fit, based on statistical theory, to earlier measurements of negative anisotropies for Esub(n)<=0.2 MeV will be discussed.The measured total kinetic energy averaged over all fragment masses, TKE-bar(Esub(n)), shows a sudden decrease at Esub(n)approx. 4.5 MeV in agreement with earlier measurements. This sudden decrease can not be explained by the measured change in the mass distribution. The present data of TKE-bar(Esub(n)) as function of mass-split reveal that TKE-bar(Esub(n)) decreases with Esub(n) for mass splits around the 104/132 split as predicted by calculations of B.D. Wilkins et al. It is also seen that TKE-bar(Esub(n)) increases with Esub(n) for the symmetric and the extreme asymmetric fissions. The very structured mass distribution from approximately cold fragmentation will be presented. (author)
Directory of Open Access Journals (Sweden)
Q Joyce Han
Full Text Available Right ventricular (RV function has increasingly being recognized as an important predictor for morbidity and mortality in patients with pulmonary arterial hypertension (PAH. The increased RV after-load increase RV work in PAH. We used time-resolved 3D phase contrast MRI (4D flow MRI to derive RV kinetic energy (KE work density and energy loss in the pulmonary artery (PA to better characterize RV work in PAH patients.4D flow and standard cardiac cine images were obtained in ten functional class I/II patients with PAH and nine healthy subjects. For each individual, we calculated the RV KE work density and the amount of viscous dissipation in the PA.PAH patients had alterations in flow patterns in both the RV and the PA compared to healthy subjects. PAH subjects had significantly higher RV KE work density than healthy subjects (94.7±33.7 mJ/mL vs. 61.7±14.8 mJ/mL, p = 0.007 as well as a much greater percent PA energy loss (21.1±6.4% vs. 2.2±1.3%, p = 0.0001 throughout the cardiac cycle. RV KE work density and percent PA energy loss had mild and moderate correlations with RV ejection fraction.This study has quantified two kinetic energy metrics to assess RV function using 4D flow. RV KE work density and PA viscous energy loss not only distinguished healthy subjects from patients, but also provided distinction amongst PAH patients. These metrics hold promise as imaging markers for RV function.
Adamovich, Igor V; Li, Ting; Lempert, Walter R
2015-08-13
This work describes the kinetic mechanism of coupled molecular energy transfer and chemical reactions in low-temperature air, H2-air and hydrocarbon-air plasmas sustained by nanosecond pulse discharges (single-pulse or repetitive pulse burst). The model incorporates electron impact processes, state-specific N2 vibrational energy transfer, reactions of excited electronic species of N2, O2, N and O, and 'conventional' chemical reactions (Konnov mechanism). Effects of diffusion and conduction heat transfer, energy coupled to the cathode layer and gasdynamic compression/expansion are incorporated as quasi-zero-dimensional corrections. The model is exercised using a combination of freeware (Bolsig+) and commercial software (ChemKin-Pro). The model predictions are validated using time-resolved measurements of temperature and N2 vibrational level populations in nanosecond pulse discharges in air in plane-to-plane and sphere-to-sphere geometry; temperature and OH number density after nanosecond pulse burst discharges in lean H2-air, CH4-air and C2H4-air mixtures; and temperature after the nanosecond pulse discharge burst during plasma-assisted ignition of lean H2-mixtures, showing good agreement with the data. The model predictions for OH number density in lean C3H8-air mixtures differ from the experimental results, over-predicting its absolute value and failing to predict transient OH rise and decay after the discharge burst. The agreement with the data for C3H8-air is improved considerably if a different conventional hydrocarbon chemistry reaction set (LLNL methane-n-butane flame mechanism) is used. The results of mechanism validation demonstrate its applicability for analysis of plasma chemical oxidation and ignition of low-temperature H2-air, CH4-air and C2H4-air mixtures using nanosecond pulse discharges. Kinetic modelling of low-temperature plasma excited propane-air mixtures demonstrates the need for development of a more accurate 'conventional' chemistry mechanism
International Nuclear Information System (INIS)
Ion beam irradiation of a solid can lead to the emission of neutral or ionized atoms, molecules or clusters from the surface. This comes as a result of the atomic motion in the vicinity of the surface, induced by the transfer of the projectile energy. Then, the study of the sputtering process appears as a means to get a better understanding of the excited matter state around the projectile trajectory. In the case of slow multicharged ions, a strong electronic excitation can be achieved by the projectile neutralization above the solid surface and / or its deexcitation below the surface. Parallel to this, the slowing down of such ions is essentially related to elastic collision with the target atoms. The study of the effect of the initial charge state of slow multicharged ions, in the sputtering process, has been carried out by measuring the absolute angular distributions of emission of uranium atoms from a uranium dioxide surface. The experiments have been performed in two steps. First, the emitted particles are collected onto a substrate during irradiation. Secondly, the surface of the collectors is analyzed by Rutherford Backscattering Spectrometry (RBS). This method allows the characterization of the emission of neutrals, which are the vast majority of the sputtered particles. The results obtained provide an access to the evolution of the sputtering process as a function of xenon projectile ions charge state. The measurements have been performed over a wide kinetic energy range, from 81 down to 1.5 keV. This allowed a clear separation of the contribution of the kinetic energy and initial projectile charge state to the sputtering phenomenon. (author)
Axial electron-channelling analysis of perovskite
International Nuclear Information System (INIS)
The orientation dependence of characteristic X-ray emission (the Borrmann effect) under near-zone-axis diffraction conditions has been used to identify the site preferences of strontium, zirconium and uranium impurities within a CaTiO3 (perovskite) host structure. As characteristic emission lines from these impurities occur at both higher and lower energies than the calcium or titanium K-shell excitations, effects of delocalization are clearly measureable, and are used as a tool in axial electron channeling or ALCHEMI analysis. It is found that strontium and uranium strongly partition into calcium sites, whereas zirconium occupies titanium sites. (author)
Computer axial tomography in geosciences
International Nuclear Information System (INIS)
Computer Axial Tomography (CAT) is one of the most adequate non-invasive techniques for the investigation of the internal structure of a large category of objects. Initially designed for medical investigations, this technique, based on the attenuation of X- or gamma-ray (and in some cases neutrons), generates digital images which map the numerical values of the linear attenuation coefficient of a section or of the entire volume of the investigated sample. Shortly after its application in medicine, CAT has been successfully used in archaeology, life sciences, and geosciences as well as for the industrial materials non-destructive testing. Depending on the energy of the utilized radiation as well as on the effective atomic number of the sample, CAT can provide with a spatial resolution of 0.01 - 0.5 mm, quantitative as well as qualitative information concerning local density, porosity or chemical composition of the sample. At present two types of axial Computer Tomographs (CT) are in use. One category, consisting of medical as well as industrial CT is equipped with X-ray tubes while the other uses isotopic gamma-ray sources. CT provided with intense X-ray sources (equivalent to 12-15 kCi or 450-550 TBq) has the advantage of an extremely short running time (a few seconds and even less) but presents some disadvantages known as beam hardening and absorption edge effects. These effects, intrinsically related to the polychromatic nature of the X-rays generated by classical tubes, need special mathematical or physical corrections. A polychromatic X-ray beam can be made almost monochromatic by means of crystal diffraction or by using adequate multicomponent filters, but these devices are costly and considerably diminish the output of X-ray generators. In the case of CT of the second type, monochromatic gamma-rays generated by radioisotopic sources, such as 169 Yb (50.4 keV), 241 Am (59 keV), 192 Ir (310.5 and 469.1 keV ) or 137 Cs (662.7 keV), are used in combination with
Lajnef, N.; Burgueño, R.; Borchani, W.; Sun, Y.
2014-05-01
A major obstacle limiting the development of deployable sensing and actuation solutions is the scarcity of power. Converted energy from ambient loading using piezoelectric scavengers is a possible solution. Most of the previously developed research focused on vibration-based piezoelectric harvesters which are typically characterized by a response with a narrow natural frequency range. Several techniques were used to improve their effectiveness. These methods focus only on the transducer’s properties and configurations, but do little to improve the stimuli from the source. In contrast, this work proposes to focus on the input deformations generated within the structure, and the induction of an amplified amplitude and up-converted frequency toward the harvesters’ natural spectrum. This paper introduces the concept of using mechanically-equivalent energy converters and frequency modulators that can transform low-amplitude and low-rate service deformations into an amplified vibration input to the piezoelectric transducer. The introduced concept allows energy conversion within the unexplored quasi-static frequency range (≪1 Hz). The post-buckling behavior of bilaterally constrained columns is used as the mechanism for frequency up-conversion. A bimorph cantilever polyvinylidene fluoride (PVDF) piezoelectric beam is used for energy conversion. Experimental prototypes were built and tested to validate the introduced concept and the levels of extractable power were evaluated for different cases under varying input frequencies. Finally, finite element simulations are reported to provide insight into the scalability and performance of the developed concept.
Czech Academy of Sciences Publication Activity Database
Okrouhlík, Miloslav; Pták, Svatopluk; Lundberg, B.; Valdek, U.
2009-01-01
Roč. 60, č. 4 (2009), s. 181-209. ISSN 0039-2472 R&D Projects: GA ČR(CZ) GA106/08/0403 Institutional research plan: CEZ:AV0Z20760514 Keywords : energy flux * stress wave propagation * experiment Subject RIV: BI - Acoustics
International Nuclear Information System (INIS)
A major obstacle limiting the development of deployable sensing and actuation solutions is the scarcity of power. Converted energy from ambient loading using piezoelectric scavengers is a possible solution. Most of the previously developed research focused on vibration-based piezoelectric harvesters which are typically characterized by a response with a narrow natural frequency range. Several techniques were used to improve their effectiveness. These methods focus only on the transducer’s properties and configurations, but do little to improve the stimuli from the source. In contrast, this work proposes to focus on the input deformations generated within the structure, and the induction of an amplified amplitude and up-converted frequency toward the harvesters’ natural spectrum. This paper introduces the concept of using mechanically-equivalent energy converters and frequency modulators that can transform low-amplitude and low-rate service deformations into an amplified vibration input to the piezoelectric transducer. The introduced concept allows energy conversion within the unexplored quasi-static frequency range (≪1 Hz). The post-buckling behavior of bilaterally constrained columns is used as the mechanism for frequency up-conversion. A bimorph cantilever polyvinylidene fluoride (PVDF) piezoelectric beam is used for energy conversion. Experimental prototypes were built and tested to validate the introduced concept and the levels of extractable power were evaluated for different cases under varying input frequencies. Finally, finite element simulations are reported to provide insight into the scalability and performance of the developed concept. (paper)
Li, Suyun; Yang, Xue; Zhang, Yanyan; Ma, Haile; Qu, Wenjuan; Ye, Xiaofei; Muatasim, Rahma; Oladejo, Ayobami Olayemi
2016-07-01
This research investigated the structural characteristics and enzymolysis kinetics of rice protein which was pretreated by energy-gathered ultrasound and ultrasound assisted alkali. The structural characteristics of rice protein before and after the pretreatment were performed with surface hydrophobicity and Fourier transform infrared (FTIR). There was an increase in the intensity of fluorescence spectrum and changes in functional groups after the pretreatment on rice protein compared with the control (without ultrasound and ultrasound assisted alkali processed), thus significantly enhancing efficiency of the enzymatic hydrolysis. A simplified kinetic equation for the enzymolysis model with the impeded reaction of enzyme was deduced to successfully describe the enzymatic hydrolysis of rice protein by different pretreatments. The initial observed rate constants (Kin,0) as well as ineffective coefficients (kimp) were proposed and obtained based on the experimental observation. The results showed that the parameter of kin,0 increased after ultrasound and ultrasound assisted alkali pretreatments, which proved the effects of the pretreatments on the substrate enhancing the enzymolysis process and had relation to the structure changes of the pretreatments on the substrate. Furthermore, the applicability of the simplified model was demonstrated by the enzymatic hydrolysis process for other materials. PMID:26964926
Statistical properties of kinetic and total energy densities in reverberant spaces
DEFF Research Database (Denmark)
Jacobsen, Finn; Molares, Alfonso Rodriguez
2010-01-01
Many acoustical measurements, e.g., measurement of sound power and transmission loss, rely on determining the total sound energy in a reverberation room. The total energy is usually approximated by measuring the mean-square pressure (i.e., the potential energy density) at a number of discrete...... modal overlap, and this analysis has never been published. Moreover, until fairly recently, measurement of the total sound energy density required an elaborate experimental arrangement based on finite-difference approximations using at least four amplitude and phase matched pressure microphones...
Energy transfer kinetics in oxy-fluoride glass and glass-ceramics doped with rare-earth ions
International Nuclear Information System (INIS)
An investigation of donor-acceptor energy transfer kinetics in dual rare earths doped precursor oxy-fluoride glass and its glass-ceramics containing NaYF4 nano-crystals is reported here, using three different donor-acceptor ion combinations such as Nd-Yb, Yb-Dy, and Nd-Dy. The precipitation of NaYF4 nano-crystals in host glass matrix under controlled post heat treatment of precursor oxy-fluoride glasses has been confirmed from XRD, FESEM, and transmission electron microscope (TEM) analysis. Further, the incorporation of dopant ions inside fluoride nano-crystals has been established through optical absorption and TEM-EDX analysis. The noticed decreasing trend in donor to acceptor energy transfer efficiency from precursor glass to glass-ceramics in all three combinations have been explained based on the structural rearrangements that occurred during the heat treatment process. The reduced coupling phonon energy for the dopant ions due to fluoride environment and its influence on the overall phonon assisted contribution in energy transfer process has been illustrated. Additionally, realization of a correlated distribution of dopant ions causing clustering inside nano-crystals has also been reported.
Beeby, Stephen P.; Wang, Leran; Zhu, Dibin; Weddell, Alex S.; Merrett, Geoff V.; Stark, Bernard; Szarka, Gyorgy; Al-Hashimi, Bashir M.
2013-07-01
The design of vibration energy harvesters (VEHs) is highly dependent upon the characteristics of the environmental vibrations present in the intended application. VEHs can be linear resonant systems tuned to particular frequencies or nonlinear systems with either bistable operation or a Duffing-type response. This paper provides detailed vibration data from a range of applications, which has been made freely available for download through the Energy Harvesting Network’s online data repository. In particular, this research shows that simulation is essential in designing and selecting the most suitable vibration energy harvester for particular applications. This is illustrated through C-based simulations of different types of VEHs, using real vibration data from a diesel ferry engine, a combined heat and power pump, a petrol car engine and a helicopter. The analysis shows that a bistable energy harvester only has a higher output power than a linear or Duffing-type nonlinear energy harvester with the same Q-factor when it is subjected to white noise vibration. The analysis also indicates that piezoelectric transduction mechanisms are more suitable for bistable energy harvesters than electromagnetic transduction. Furthermore, the linear energy harvester has a higher output power compared to the Duffing-type nonlinear energy harvester with the same Q factor in most cases. The Duffing-type nonlinear energy harvester can generate more power than the linear energy harvester only when it is excited at vibrations with multiple peaks and the frequencies of these peaks are within its bandwidth. Through these new observations, this paper illustrates the importance of simulation in the design of energy harvesting systems, with particular emphasis on the need to incorporate real vibration data.
Cars and Kinetic Energy--Some Simple Physics with Real-World Relevance
Parthasarathy, Raghuveer
2012-01-01
Understanding energy usage is crucial to understanding modern civilization, as well as many of the challenges it faces. Energy-related issues also offer real-world examples of important physical concepts, and as such have been the focus of several articles in "The Physics Teacher" in the past few decades (e.g., Refs. 1-5, noted further below).…
International Nuclear Information System (INIS)
Embedded-atom molecular dynamics simulations are used to investigate the effects of low-energy self-ion irradiation of Pt adatoms on Pt(111). Here, we concentrate on self-bombardment dynamics, i.e., isolating and monitoring the atomic processes, induced by normally incident Pt atoms with energies E ranging from 5 to 50 eV, that can affect intra- and interlayer mass transport.. We find that adatom scattering, surface channeling, and dimer formation occur at all energies. Atomic intermixing events involving incident and terrace atoms are observed at energies ≥15 eV, while the collateral formation of residual surface vacancies is observed only with E>40 eV. The overall effect of low-energy self-ion irradiation is to enhance lateral adatom and terrace atom migration
International Nuclear Information System (INIS)
A differential equation for the Dirac density matrix γ(r, r'), given ground-state electron- and kinetic energy-densities, has been derived by March and Suhai for one- and two-level occupancy. For ten-electron spin-compensated spherical systems, it is shown here that γ ≡ γ[ρ, tg] where ρ and tg are electron- and kinetic energy-densities. The philosophy of March and Suhai is confirmed beyond two-level filling. An important byproduct of the present approach is an explicit expression for the one-body potential of DFT in terms of the p-shell electron density. (author)
International Nuclear Information System (INIS)
Reactor fuel elements generally consist of rod bundles with the coolant flowing axially through the bundles in the space between the rods. Heat transfer calculations form an important part in the design of such elements, which can only be carried out if information of the velocity field is available. A one-equation statistical model of turbulence is applied to compute the detailed description of velocity field (axial and secondary flows) and the wall shear stress distribution of steady, fully developed turbulent flows with incompressible, temperature-independent fluid, flowing through triangular arrays of rods with different aspect ratios (P/D). Also experimental measurements of the distributions of the axial velocity, turbulence kinetic energy, and Reynolds stresses were performed using a laser Doppler anemometer (LDA), operating in a ''fringe'' mode with forward scattering, in a simulated interior subchannel of a triangular rod array with P/D = 1.123 and L/D/sub H/ = 77. From the experimental results, a new mixing length distribution is proposed. Comparisons between the analytical results and the results of this experiment as well as other experimental data available in the literature are presented. The results are in good agreement
International Nuclear Information System (INIS)
Ionization and fragmentation of CO molecules have been investigated in charge-changing collisions of B''2''+ ions at v = 1.69 a.u.. Fragment ions from CO were measured by using a momentum 3D imaging technique in coincidence with outgoing projectile charge states. We deduced the kinetic energy release (KER) associated with charge-changing collisions of B''2''+ to B''3''+, B''1''+ and B''0''+. The KER spectra in the fragmentation to C''+ and O''+ ions are found to be different to some extent for these loss and capture collisions. It is concluded that the electron loss collision populates the intact CO molecule to highly excited states of (CO)''2''+''1 more effectively than electron capture collisions, resulting from different effective impact parameters associated with loss and capture collisions.
Runov, A. M.; Kasilov, S. V.; Helander, P.
2015-11-01
A kinetic Monte Carlo model suited for self-consistent transport studies is proposed and tested. The Monte Carlo collision operator is based on a widely used model of Coulomb scattering by a drifting Maxwellian and a new algorithm enforcing the momentum and energy conservation laws. The difference to other approaches consists in a specific procedure of calculating the background Maxwellian parameters, which does not require ensemble averaging and, therefore, allows for the use of single-particle algorithms. This possibility is useful in transport balance (steady state) problems with a phenomenological diffusive ansatz for the turbulent transport, because it allows a direct use of variance reduction methods well suited for single particle algorithms. In addition, a method for the self-consistent calculation of the electric field is discussed. Results of testing of the new collision operator using a set of 1D examples, and preliminary results of 2D modelling in realistic tokamak geometry, are presented.
Energy Technology Data Exchange (ETDEWEB)
Al-Taee, M.A. [Amman University (Jordan). Electrical Engineering Dept.; Al-Azzawi, F.J.; Al-Taee, A.A.; Al-Jumaily, T.Z. [Baghdad Univ. (Iraq). Electrical Engineering Dept.
2001-11-01
The effectiveness of the rate of change of kinetic energy (RACKE) in defining power system stability was studied previously using off-line computer simulation. Theoretical analyses indicated the effectiveness of this method in deciding transient stability of power systems, and its effectiveness in increasing the stability margin when a dynamic brake element is used. The practical implementation of the RACKE method with a resistive dynamic brake is presented. The brake insertion and removal instants are decided on-line by a microcomputer controller. The hardware and software design considerations of the proposed controller are described. The observed behaviour of the power system prototype during fault conditions is found to be in agreement with that obtained from simulation tests. (author)
Bischof, Günter; Reisinger, Karl; Singraber, Thomas; Summer, Andreas
2014-02-01
With the advent of flywheel-based kinetic energy recovery systems in automotive applications new safety issues arise as a consequence of the flywheel's high rotational speed. While the special structural safety requirements of the components are well discussed in the literature, there is still little research on the influence of gyroscopic effects on vehicle dynamics. The aim of this paper is to investigate the influence of a typical high-speed flywheel on the driving dynamics of an average passenger car. To this end the equations of motion of a gyroscope are derived, which relate the vehicle's roll, pitch and yaw rate with the transverse torque acting on the flywheel. These equations are implemented in a commercial vehicle dynamics simulation program in order to determine the reaction torques acting on the vehicle within a representative range of driving situations. Numerical simulations indicate that the gyroscopic effect can be considered insignificant in standard driving situations.
Ab initio free energy of vacancy formation and mass-action kinetics in vis-active TiO2
International Nuclear Information System (INIS)
Recent reports have identified bulk defects such as oxygen vacancies as key players in visible-light photoactive TiO2. This would imply greater visible light absorption rates may be possible provided effective defect engineering can be achieved. To further this we have developed methods to simulate vacancy formation in bulk TiO2 using ab initio techniques. Initial results of these methods show an entropic reduction in the free energy of vacancy formation of 2.3 eV over a range of 266 K. The use of this result is illustrated by a 'toy' mass-action kinetics model which offers insight into vacancy concentration, rate constants, and enthalpy of reaction. (fast track communication)
Xie, Hongtao; Wang, Shiliang; Huang, Han
2016-02-12
SiC nanowires were manipulated under an optic microscope to investigate the nanoscale friction between nanowires and a flat substrate. The deflection of the nanowires was modeled as that of an Euler-Bernoulli beam subjected to a uniformly distributed load. A simple formula was developed to calculate the kinetic friction from the normalized deflections at the two ends of a nanowire. The frictional force per unit area determined ranges from 0.18-0.51 MPa. Both experimental and simulated results demonstrated that the proposed approach was reliable. The results were also compared with those estimated using an energy-conservation model, which produced a frictional force ranging from 0.21-0.62 MPa. The results obtained from the two different methods are in excellent agreement. PMID:26762859
Dulak, Marcin; Wesolowski, Tomasz Adam
2006-01-01
The bifunctional of the nonadditive kinetic energy in the reference system of noninteracting electrons ( [ρA, ρB] = Ts[ρA + ρB] − Ts[ρA] − Ts[ρB]) is the key quantity in orbital-free embedding calculations because they hinge on approximations to [ρA,ρB]. Since [ρA,ρB] is not linear in ρA, the associated potential (functional derivative) [ρ,ρB]/δρ|ρ=ρA(r) changes if ρA varies. In this work, for two approximations to [ρA,ρB], which are nonlinear in ρA (gradient-free and gradient-dependent), the...
International Nuclear Information System (INIS)
We propose and study analytically a statistical mechanical model of reversible aggregation in anisotropic and isotropic solvents for small solute concentrations c. An aggregate comprising n solute molecules is a one-dimensional structureless flexible rod, n-mer, which interacts with the solvent anisotropy. The solvent is a nematic liquid crystal described by its scalar order parameter. The kinetic energy of n-mers is shown to play a unique role in the thermodynamic equilibrium. The kinetic energy contribution to the partition function is modeled by the term nq, where q is determined by the persistence lengths of different translation–rotation modes (e.g. q = 5 for a rigid rod and q≈0 for a very flexible chain). The n-mer concentration is found to depend on c via its powers which are fully determined by the parameter q. The solvent anisotropy results in a larger fraction of longer aggregates and gives rise to two different aggregation regimes: a low n regime for lower solute concentration c and a high n regime for higher c. The total aggregate concentration is found to be a sum of universal power laws of c with the exponents that are different for anisotropic and isotropic solvents, but in both cases are determined solely by the parameter q. The analytical formulae for the two regimes and the crossover point (which can be naturally associated with the critical micelle concentration) are in a quantitative agreement with the numerical solution of the model. The model is pertinent to self-assemblies of plank-like dye molecules dissolved in an isotropic solvent (related to chromonic liquid crystals) and in a nematic liquid crystal
Kinetics and energy efficiency for the degradation of 1,4-dioxane by electro-peroxone process
International Nuclear Information System (INIS)
Highlights: • E-peroxone couples electrolysis with ozonation to driven peroxone reaction for pollutant degradation. • Significant amounts of ·OH can be efficiently produced in the E-peroxone process. • E-peroxone greatly enhances 1,4-dioxane degradation kinetics compared with ozonation and electrolysis. • E-peroxone consumes less energy for 1,4-dioxane mineralization than ozonation and electrolysis. • E-peroxone offers a cost-effective and energy-efficient alternative to degrade 1,4-dioxane. - Abstract: Degradation of 1,4-dioxane by ozonation, electrolysis, and their combined electro-peroxone (E-peroxone) process was investigated. The E-peroxone process used a carbon-polytetrafluorethylene cathode to electrocatalytically convert O2 in the sparged ozone generator effluent (O2 and O3 gas mixture) to H2O2. The electro-generated H2O2 then react with sparged O3 to yield aqueous ·OH, which can in turn oxidize pollutants rapidly in the bulk solution. Using p-chlorobenzoic acid as ·OH probe, the pseudo-steady concentration of ·OH was determined to be ∼0.744 × 10−9 mM in the E-peroxone process, which is approximately 10 and 186 times of that in ozonation and electrolysis using a Pt anode. Thanks to its higher ·OH concentration, the E-peroxone process eliminated 96.6% total organic carbon (TOC) from a 1,4-dioxane solution after 2 h treatment with a specific energy consumption (SEC) of 0.376 kWh g−1 TOCremoved. In comparison, ozonation and electrolysis using a boron-doped diamond anode removed only ∼6.1% and 26.9% TOC with SEC of 2.43 and 0.558 kWh g−1 TOCremoved, respectively. The results indicate that the E-peroxone process can significantly improve the kinetics and energy efficiency for 1,4-dioxane mineralization as compared to the two individual processes. The E-peroxone process may thus offer a highly effective and energy-efficient alternative to treat 1,4-dioxane wastewater
Kinetics and energy efficiency for the degradation of 1,4-dioxane by electro-peroxone process
Energy Technology Data Exchange (ETDEWEB)
Wang, Huijiao; Bakheet, Belal; Yuan, Shi; Li, Xiang; Yu, Gang [School of Environment, Tsinghua University, Beijing 100084 (China); Murayama, Seiichi [Power and Industrial Systems R& D Center, Toshiba Corporation, Fuchu-shi, Tokyo (Japan); Wang, Yujue, E-mail: wangyujue@tsinghua.edu.cn [School of Environment, Tsinghua University, Beijing 100084 (China)
2015-08-30
Highlights: • E-peroxone couples electrolysis with ozonation to driven peroxone reaction for pollutant degradation. • Significant amounts of ·OH can be efficiently produced in the E-peroxone process. • E-peroxone greatly enhances 1,4-dioxane degradation kinetics compared with ozonation and electrolysis. • E-peroxone consumes less energy for 1,4-dioxane mineralization than ozonation and electrolysis. • E-peroxone offers a cost-effective and energy-efficient alternative to degrade 1,4-dioxane. - Abstract: Degradation of 1,4-dioxane by ozonation, electrolysis, and their combined electro-peroxone (E-peroxone) process was investigated. The E-peroxone process used a carbon-polytetrafluorethylene cathode to electrocatalytically convert O{sub 2} in the sparged ozone generator effluent (O{sub 2} and O{sub 3} gas mixture) to H{sub 2}O{sub 2}. The electro-generated H{sub 2}O{sub 2} then react with sparged O{sub 3} to yield aqueous ·OH, which can in turn oxidize pollutants rapidly in the bulk solution. Using p-chlorobenzoic acid as ·OH probe, the pseudo-steady concentration of ·OH was determined to be ∼0.744 × 10{sup −9} mM in the E-peroxone process, which is approximately 10 and 186 times of that in ozonation and electrolysis using a Pt anode. Thanks to its higher ·OH concentration, the E-peroxone process eliminated 96.6% total organic carbon (TOC) from a 1,4-dioxane solution after 2 h treatment with a specific energy consumption (SEC) of 0.376 kWh g{sup −1} TOC{sub removed}. In comparison, ozonation and electrolysis using a boron-doped diamond anode removed only ∼6.1% and 26.9% TOC with SEC of 2.43 and 0.558 kWh g{sup −1} TOC{sub removed}, respectively. The results indicate that the E-peroxone process can significantly improve the kinetics and energy efficiency for 1,4-dioxane mineralization as compared to the two individual processes. The E-peroxone process may thus offer a highly effective and energy-efficient alternative to treat 1,4-dioxane
International Nuclear Information System (INIS)
Equal channel angular pressing (ECAP) was conducted at 250 °C on commercial purity titanium up to 10 passes. An ultrafine-grained microstructure with a mean grain size of about 183 nm was obtained. The evolution of stored energy and recrystallization temperature was studied by differential scanning calorimetry. The activation energy involved in the recrystallization process was also determined. The results show that with increase of ECAP passes up to 6 the recrystallization temperature increases. Also, it is seen that with increasing ECAP passes up to 8 the stored energy increases, beyond which it saturates at a value of about 58 J/mol. For the recrystallization of 10 passes ECAP-ed samples, average activation energy of about 342 kJ/mol was determined
Energy Technology Data Exchange (ETDEWEB)
Baker, C.G.J.
1999-09-01
Precious work has shown that it is possible to predict the size of a continuous well-mixed fluidized bed dryer from batch drying curve measurements. This approach has been extended in the present study to include energy consumption calculations. A computer code was written to simulate the performance of the dryer and to determine its specific energy consumption E{sub s}. Starting in this case with an isothermal bed batch drying curve, the program first calculates the mean solids residence time required under specified operating conditions. Mass and energy balances are then used to calculate the heat duty and E{sub s}. The bed temperature was found to have a significant effect on specific energy consumption in all cases. However, the influences of air flowrate and humidity, and of solids loading, were shown to depend on the solids drying characteristics.
Chen, Tianju; Zhang, Jinzhi; Wu, Jinhu
2016-07-01
The kinetic and energy productions of pyrolysis of a lignocellulosic biomass were investigated using a three-parallel Gaussian distribution method in this work. The pyrolysis experiment of the pine sawdust was performed using a thermogravimetric-mass spectroscopy (TG-MS) analyzer. A three-parallel Gaussian distributed activation energy model (DAEM)-reaction model was used to describe thermal decomposition behaviors of the three components, hemicellulose, cellulose and lignin. The first, second and third pseudocomponents represent the fractions of hemicellulose, cellulose and lignin, respectively. It was found that the model is capable of predicting the pyrolysis behavior of the pine sawdust. The activation energy distribution peaks for the three pseudo-components were centered at 186.8, 197.5 and 203.9kJmol(-1) for the pine sawdust, respectively. The evolution profiles of H2, CH4, CO, and CO2 were well predicted using the three-parallel Gaussian distribution model. In addition, the chemical composition of bio-oil was also obtained by pyrolysis-gas chromatography/mass spectrometry instrument (Py-GC/MS). PMID:27035484
International Nuclear Information System (INIS)
To obtain information on the energy of deformation of fission fragments of tpansfermium isotopes in the correlation with prompt neutrons, a binary ionization chamber for the measurement of emission angle of fission fragments relatively to cathode plane, is developed. A range chamber is placed into the ionization chamber having lavsan windows in the 5 mm cathode plane. Two identical chambers with that parallel electrodes have a common cathode, screen grids in front of anode and signal grids in front of screen grids which serve to determine the emission angle of fission fragments. The cathode-signal (first) grid-screen (second) grid-collecting electrode distances are 32.7 and 10 mm, respectively. The grids are made of nichromium wire 100 μm thick, which is wired with the spacing of 1.5 and 1.0 mm for the first and for the second grid respectively. Chamber characteristics are: angle resolution 3-8 deg, energy resolution 1.5%, mass resolution 2-3 a m.u. Results of model experiments are presented. Spectra f 235U, fission fragments, those of distribution of fission fragments in mass and total kinetic energy are measured
Pradal, Delphine; Vauchel, Peggy; Decossin, Stéphane; Dhulster, Pascal; Dimitrov, Krasimir
2016-09-01
Ultrasound-assisted extraction (UAE) of antioxidant polyphenols from chicory grounds was studied in order to propose a suitable valorization of this food industry by-product. The main parameters influencing the extraction process were identified. A new mathematical model for multi-criteria optimization of UAE was proposed. This kinetic model permitted the following and the prediction of the yield of extracted polyphenols, the antioxidant activity of the obtained extracts and the energy consumption during the extraction process in wide ranges of temperature (20-60°C), ethanol content in the solvent (0-60% (vol.) in ethanol-water mixtures) and ultrasound power (0-100W). After experimental validation of the model, several simulations at different technological restrictions were performed to illustrate the potentiality of the model to find the optimal conditions for obtaining a given yield within minimal process duration or with minimal energy consumption. The advantage of ultrasound assistance was clearly demonstrated both for the reduction of extraction duration and for the reduction of energy consumption. PMID:27150754
Institute of Scientific and Technical Information of China (English)
延玺; 王国清; 朱文祥; 刘向荣; 朱守荣; 林华宽; 朱志昂; 陈荣悌
2001-01-01
模拟维生素B12合成了水溶性的高氯酸双氯（5，7，7，12，14，14-六甲基-1，4，8，11-四氮杂环十四烷）钴（Ⅲ）配合物，用停流分光光度计对甘氨酸等5种氨基酸与该配合物的轴向快速反应动力学性质进行了研究，探讨了它们的反应机制，对实验数据进行了拟合处理，得到预平衡步的平衡常数K和速控步的速率常数k，并算出了预平衡步的△r,△r以及速控步的△≠rHm,△≠rSm。在实验的基础上，提出了维生素B12治疗肝脏疾病的可能原因。%Thedichloro(5,7,7,12,14,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane) Cobalt(Ш) perchlorate 〔Co(C16H36N4)Cl2〕ClO4 was synthesized for the imitation of vitamin B12.The kinetic study on axial coordination fast reaction between 〔Co(C16H36N4)Cl2〕ClO4 and five amino-acid compounds at different temperatures by means of the union Giken RA-401 stopped-flow was reported.The mechanism of the reaction was postulated.The equilibrium constants K of the pre-equilibrium step and the rate constants k of rate-determining step were evaluated.The △r,△r of the prequilibrium step and △≠rHm,△≠rSm of the rate-determining step were also calculated.
Proton spin and baryon octet axial couplings
International Nuclear Information System (INIS)
Peripheral spin structure of the nucelon generated by the soft mesonic radiative corrections is studied within the light-cone perturbation theory. Starting with the tree-level SU(6) symmetry, we find a good description of the axial-vector couplings in β-decay of hyperons. We study the proton helicity flow from the baryonic core to the angular momentum of the pionic cloud. It is found that in the relativistic light-cone approach the spin-flip pattern is different from that in the coventional non-relativistic models. The axial-vector current matrix elements are shown to receive large corrections from beyond the conventional static limit. The important virtue of using the light-cone vertex functions of the meson-baryon Fock components of the proton is that the local gauge invariance and the energy-momentum sum rule are satisfied automatically. We infer the radius of the light-cone form factor from an analysis of the experimental data on the fragmentation of high-energy protons into nucleons and hyperons-the process dominated by stripping off the mesons of the meson-baryon Fock states. (orig.)
Energy Technology Data Exchange (ETDEWEB)
Duke, Dana Lynn [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
2015-11-12
This Ph.D. dissertation describes a measurement of the change in mass distributions and average total kinetic energy (TKE) release with increasing incident neutron energy for fission of ^{235}U and ^{238}U. Although fission was discovered over seventy-five years ago, open questions remain about the physics of the fission process. The energy of the incident neutron, En, changes the division of energy release in the resulting fission fragments, however, the details of energy partitioning remain ambiguous because the nucleus is a many-body quantum system. Creating a full theoretical model is difficult and experimental data to validate existing models are lacking. Additional fission measurements will lead to higher-quality models of the fission process, therefore improving applications such as the development of next-generation nuclear reactors and defense. This work also paves the way for precision experiments such as the Time Projection Chamber (TPC) for fission cross section measurements and the Spectrometer for Ion Determination in Fission (SPIDER) for precision mass yields.
View of the Axial Field Spectrometer
1980-01-01
The Axial Field Spectrometer, with the vertical uranium/scintillator calorimeter and the central drift chamber retracted for service. One coil of the Open Axial Field Magnet is just visible to the right.
Energy Technology Data Exchange (ETDEWEB)
Tatry, B.
1976-02-01
The feasibility of using solar energy to feed an autonomous station providing electric current continuously was studied. As an energy storage device a 'superflywheel' (rotor with composite fibers - magnetic bearings) would be used. Results show that such an experiment can be reasonably envisaged only in highly sunny countries and that it becomes non profitable at our latitudes, despite the very good performance of the flywheel storage device.
Simulation of an Axial Vircator
Tikhomirov, V. V.; Siahlo, S. E.
2013-01-01
An algorithm of particle-in-cell simulations is described and tested to aid further the actual design of simple vircators working on axially symmetric modes. The methods of correction of the numerical solution, have been chosen and jointly tested, allow the stable simulation of the fast nonlinear multiflow dynamics of virtual cathode formation and evolution, as well as the fields generated by the virtual cathode. The selected combination of the correction methods can be straightforwardly gene...
Axial-vector dominance predictions in quasielastic neutrino-nucleus scattering
Amaro, J E
2015-01-01
We use the minimum meson-dominance ansatz compatible with low- and high energy constrains to model the nucleon axial form factor. The parameters of the resulting axial form factor are the masses and widths of the two axial mesons, incorporated as a product of monopoles. By applying the half width rule in a Monte Carlo simulation a distribution of theoretical predictions can be generated for the neutrino-nucleus quasielastic cross section. We test the model by applying it to the $(\
International Nuclear Information System (INIS)
The differential energy characterisation of neutron emission or fluxes may be called difficult especially when an approach to metrological standards is required. The use of somewhat complex computing programmes is unavoidable here since the process of selective detection and interpretation of measurement results involves: - Firstly of need to simulate by so-called MONTE CARLO techniques the responses of the various kinds of detector used (the detector responses are so dependent on changes in the environment that experimental calibration -too expensive to be easily repeated from one situation to the next- cannot be recommended); - secondly the need to answer pratically (in a discretized situation by matrix manipulations) to the problem, theoretically without a unique analytical solution, of resolving a Fredholm equation of the first kind. For the understanding, use and as necessary modification of the appropriate codes it is most important to have a very precise conceptual view of the mechanisms involved (in the sequence of direct instrumental transformations). For didactic purposes the present article attempts in a very simple case to give an idea, at increasing levels of complexity: stylisation, schematisation, modelisation, simulation, of the successive stage (neutron-proton energy transfer, analog conversion of ionising particle energy into electric impulse signal size) involved in the formation and understanding of an energy spectrum of recoil nuclei. All these instrumental distortions are made explicit in a kind of underlying two-dimensional ''density''; in its discretized form this is called the instrumental transfer matrix and its understanding and treatment are the ''keys'' to the deconvolution of the recorded spectrum, giving access to the differental distribution of the emitted neutron energies
An Axial Vector Photon in a Mirror World
Sharafiddinov, Rasulkhozha S
2015-01-01
The unity of symmetry laws emphasizes, in the case of a mirror CP-even Dirac Lagrangian, the ideas of the left- and right-handed axial-vector photons referring to long- and short-lived bosons of true neutrality, respectively. Such a difference in lifetimes expresses the unidenticality of masses, energies and momenta of axial-vector photons of the different components. They define the unified field theory equation of C-odd particles with an integral spin. Together with a new equation of a theory of truly neutral particles with the half-integral spin, the latter reflects the availability in their nature of the second type of the local axial-vector gauge transformation responsible for origination in the Lagrangian of C-oddity of an interaction Newton component giving an axial-vector mass to all the interacting particles and fields. The mirror axial-vector mass, energy and momentum operators constitute a CP-invariant equation of quantum mechanics, confirming that each of them can individually influence on matter ...
An Axial-Vector Photon in a Mirror World
Sharafiddinov, Rasulkhozha S.
2016-03-01
The unity of symmetry laws emphasizes, in the case of a mirror CP-even Dirac Lagrangian, the ideas of the left- and right-handed axial-vector photons referring to long- and short-lived bosons of true neutrality, respectively. Such a difference in lifetimes expresses the unidenticality of masses, energies and momenta of axial-vector photons of the different components. They define the unified field theory equation of C-odd particles with an integral spin. Together with a new equation of a theory of truly neutral particles with the half-integral spin, the latter reflects the availability in their nature of the second type of the local axial-vector gauge transformation responsible for origination in the Lagrangian of C-oddity of an interaction Newton component giving an axial-vector mass to all the interacting particles and fields. The mirror axial-vector mass, energy and momentum operators constitute a CP-invariant equation of quantum mechanics, confirming that each of them can individually influence on matter field. Thereby, findings suggest at the level of the mass-charge structure of gauge invariance a new equation for the C-noninvariant Lagrangian.
Axially symmetric static sources of gravitational field
Hernandez-Pastora, J L; Martin, J
2016-01-01
A general procedure to find static and axially symmetric, interior solutions to the Einstein equations is presented. All the so obtained solutions, verify the energy conditions for a wide range of values of the parameters, and match smoothly to some exterior solution of the Weyl family, thereby representing globally regular models describing non spherical sources of gravitational field. In the spherically symmetric limit, all our models converge to the well known incompressible perfect fluid solution.The key stone of our approach is based on an ansatz allowing to define the interior metric in terms of the exterior metric functions evaluated at the boundary source. Some particular sources are obtained, and the physical variables of the energy-momentum tensor are calculated explicitly, as well as the geometry of the source in terms of the relativistic multipole moments. The total mass of different configurations is also calculated, it is shown to be equal to the monopole of the exterior solution.
Latypov, A. F.
2012-11-01
An expression for maximum permissible entropy gain is obtained and the condition of passage via the velocity of sound is found for the steady-state flow of an ideal gas in a channel of variable cross section in the presence of heat supply and kinetic energy dissipation. Particular flow examples are considered.
Camp, E.; Cal, R. B.
2015-12-01
To optimize the power production of large wind farms, it is important to understand the flow within the wind turbine array as well as its interaction with the surrounding atmosphere. Computational simulations are often employed to study both the velocity field within and immediately above wind farms. In many computational studies, wind turbines are modeled as stationary, porous actuator discs. A wind tunnel study is done in order to compare the wakes within an array of porous discs and an equivalent array of model wind turbines. To characterize the wakes within a 4×3 model wind farm, stereoscopic particle image velocimetry (SPIV) is employed. SPIV measurements focus on the region along the centerline of the array upstream and downstream of the center turbine in the fourth row. The computed mean flow fields and turbulent stresses provide a basis to compare the near and far wakes of the turbines with those of the porous discs. The detailed analysis of the wakes for each case focus on the mean kinetic energy budget within the wakes. Examining the mean kinetic energy budget is done via computing the mean kinetic energy, flux of kinetic energy, and production of turbulence which are analogous to a measure of extracted power.
Hartogensis, O.K.; Debruin, H.A.R.
2005-01-01
The Monin-Obukhov similarity theory (MOST) functions fepsi; and fT, of the dissipation rate of turbulent kinetic energy (TKE), ¿, and the structure parameter of temperature, CT2, were determined for the stable atmospheric surface layer using data gathered in the context of CASES-99. These data cover
Marini Bettolo Marconi, Umberto; Maggi, Claudio; Melchionna, Simone
2016-06-29
We discuss different definitions of pressure for a system of active spherical particles driven by a non-thermal coloured noise. We show that mechanical, kinetic and free-energy based approaches lead to the same result up to first order in the non-equilibrium expansion parameter. The first prescription is based on a generalisation of the kinetic mesoscopic virial equation and expresses the pressure exerted on the walls in terms of the average of the virial of the inter-particle forces. In the second approach, the pressure and the surface tension are identified with the volume and area derivatives, respectively, of the partition function associated with the known stationary non-equilibrium distribution of the model. The third method is a mechanical approach and is related to the work necessary to deform the system. The pressure is obtained by comparing the expression of the work in terms of local stress and strain with the corresponding expression in terms of microscopic distribution. This is determined from the force balance encoded in the Born-Green-Yvon equation. Such a method has the advantage of giving a formula for the local pressure tensor and the surface tension even in inhomogeneous situations. By direct inspection, we show that the three procedures lead to the same values of the pressure, and give support to the idea that the partition function, obtained via the unified coloured noise approximation, is more than a formal property of the system, but determines the stationary non-equilibrium thermodynamics of the model. PMID:27301440
Carjan, N.; Ivanyuk, F. A.; Oganessian, Yu.; Ter-Akopian, G.
2015-10-01
The total deformation energy at scission for Z = 100, 102, 104 and 106 isotopes is calculated using the Strutinsky's procedure and nuclear shapes described in terms of Cassinian ovals generalized by the inclusion of three additional shape parameters: α1, α4 and α6. The corresponding fragment-mass distributions are estimated supposing they are due to thermal fluctuations in the mass asymmetry degree of freedom. For these four series of isotopes the experimentally observed transition from asymmetric to symmetric fission, that happens with increasing mass number A, is qualitatively reproduced. In lighter isotopes (e.g. 254Fm and 254Rf) two mass-asymmetric fission modes are predicted to occur with comparable yields: one having relatively compact and the other relatively elongated scission configurations. On the other hand, in heavier isotopes (e.g. 264Fm and 264Rf) the fragment-mass distributions are predicted to be narrow single-peaked around A / 2 corresponding to essentially one mass-symmetric fission mode. The mass distributions are estimated separately for each fission mode, in the case of Fm and Rf isotopes, in order to display their inversion when A increases. Finally the distributions of the total kinetic energy of the fragments are calculated, for the same isotopes, in the point-charge approximation. Non-Gaussian shapes are obtained. With increasing mass number A, a transition from a distribution tailing towards higher energies to a distribution tailing towards lower energies and an increase of the difference in the peak positions of the two modes were observed; again in qualitative agreement with experimental data.
International Nuclear Information System (INIS)
The paper begins by briefly outlining possible uses of the kinetic energy of fission products in the case of gaseous phase weak G reactions. The problem is mainly one of the amount of energy available; industrial production would require ionizing radiation energies of several tens of megawatts. At the second Geneva Conference (September 1958), some of the present authors proposed, for the first time, the use of microporous nuclear fuels as a solution. A body of supplementary data obtained with these fuels in given; they refer to decomposition of N2O, methane radiolysis, and fixation of nitrogen in the form of oxides. The results of the experiments are described with reference to the following parameters: radiation dose, type of radiation, type and dimensions of the microporous support surface. This work confirms the existence of a phenomenon which we term 'heterogeneous radiocatalysis' and enables its nature to be better defined. The nitrogen fixation reaction carried out with these fuels has some interesting features. In some cases, the rate of formation of the nitrogen oxides varies little for oxygen burn-up rates ranging up to 50%. The apparent G, calculated with reference to the total fission energy dissipated in the ''solid/ reactive gas'' system varies, according to case, from 0.1 to 0.4. The temperature is 80o C and the pressure approximately 25 atmospheres. A thorough study of the microstructure of the solids used has been begun, and the spectrum of the pores has been measured. A rough theoretical sketch of the phenomenon of ''heterogenous radiocatalysis'' is tentatively put forward. The paper ends with a discussion of how such microporous fuels could be used in the building of ''chemonuclear '' reactors. A brief study of some possible solutions shows what difficulties are still to be overcome. (author)
Srinivasan, Supramaniam; Velev, Omourtag A.; Parthasathy, Arvind; Manko, David J.; Appleby, A. John
1991-01-01
The development of proton exchange membrane (PEM) fuel cell power plants with high energy efficiencies and high power densities is gaining momentum because of the vital need of such high levels of performance for extraterrestrial (space, underwater) and terrestrial (power source for electric vehicles) applications. Since 1987, considerable progress has been made in achieving energy efficiencies of about 60 percent at a current density of 200 mA/sq cm and high power densities (greater than 1 W/sq cm) in PEM fuel cells with high (4 mg/sq cm) or low (0.4 mg/sq cm) platinum loadings in electrodes. The following areas are discussed: (1) methods to obtain these high levels of performance with low Pt loading electrodes - by proton conductor impregnation into electrodes, localization of Pt near front surface; (2) a novel microelectrode technique which yields electrode kinetic parameters for oxygen reduction and mass transport parameters; (3) demonstration of lack of water transport from anode to cathode; (4) modeling analysis of PEM fuel cell for comparison with experimental results and predicting further improvements in performance; and (5) recommendations of needed research and development for achieving the above goals.
Pre-Study for a Battery Storage for a Kinetic Energy Storage System
Svensson, Henrik
2015-01-01
This bachelor thesis investigates what kind of battery system that is suitable for an electric driveline equipped with a mechanical fly wheel, focusing on a battery with high specific energy capacity. Basic battery theory such as the principle of an electrochemical cell, limitations and C-rate is explained as well as the different major battery systems that are available. Primary and secondary cells are discussed, including the major secondary chemistries such as lead acid, nickel cadmium (Ni...
Study of the charge kinetics of MgO (1 1 0) subjected to high energy electron irradiation
Energy Technology Data Exchange (ETDEWEB)
Boughariou, A., E-mail: aicha_boughariou@yahoo.fr [LaMaCoP, Université de Sfax pour le sud, Faculté des Sciences, 3038 Sfax Tunisie (Tunisia); Kallel, A. [LaMaCoP, Université de Sfax pour le sud, Faculté des Sciences, 3038 Sfax Tunisie (Tunisia); Blaise, G. [LPS, Université Paris-Sud XI, Batiment 510, Orsay 91405 (France)
2014-09-15
Highlights: • Variation of the logarithm of SEE yield with the injected dose in MgO (1 1 0) at high energy. • Critical energy E{sub C} of MgO (1 1 0). • Formation of an electrostatic mirror. • Breakdown phenomenon (current density effect). - Abstract: This article presents a study performed with a dedicated scanning electron microscope (SEM) on the electrical property evolution of magnesium oxide (1 1 0) single crystal during 15 and 30 keV irradiation. First, the charging behavior is studied during the charge injection process at low current density J{sub 0}, by measuring the logarithm of the secondary electron emission yield (lnσ). Next, we have investigated the dependence on the current density of the charge-trapping phenomena in MgO (1 1 0). The results shown that beyond the crossover energy E{sub 2}, the observed effects varies depending on whether the energy of the primary electrons is lower or higher than an energy called critical energy E{sub c} = 20 keV (in the case of MgO (1 1 0)). When irradiating the material at E{sub 0} < E{sub c} and at low J{sub 0}, self regulated regime is obtained, if J{sub 0} is sufficiently intense an aging regime is reached. This latter regime is characterized by a positive surface charge, when a negative charge was expected. At E{sub 0} > E{sub c}, and for low J{sub 0}, the detailed monitoring of the charge kinetic of MgO (1 1 0) at high primary energy E{sub 0} = 30 keV, permit to show that the combined effect of the increased negative surface potential during irradiation and extractor field below the surface of MgO fact that lnσ undergoes a strong slope failure at the beginning of the injection and stabilizes at a value much less than zero leading to the formation of an electrostatic mirror. At high J{sub 0}, the consequences of the charge accumulation are violent and a breakdown phenomenon is observed.
Study of the charge kinetics of MgO (1 1 0) subjected to high energy electron irradiation
International Nuclear Information System (INIS)
Highlights: • Variation of the logarithm of SEE yield with the injected dose in MgO (1 1 0) at high energy. • Critical energy EC of MgO (1 1 0). • Formation of an electrostatic mirror. • Breakdown phenomenon (current density effect). - Abstract: This article presents a study performed with a dedicated scanning electron microscope (SEM) on the electrical property evolution of magnesium oxide (1 1 0) single crystal during 15 and 30 keV irradiation. First, the charging behavior is studied during the charge injection process at low current density J0, by measuring the logarithm of the secondary electron emission yield (lnσ). Next, we have investigated the dependence on the current density of the charge-trapping phenomena in MgO (1 1 0). The results shown that beyond the crossover energy E2, the observed effects varies depending on whether the energy of the primary electrons is lower or higher than an energy called critical energy Ec = 20 keV (in the case of MgO (1 1 0)). When irradiating the material at E0 < Ec and at low J0, self regulated regime is obtained, if J0 is sufficiently intense an aging regime is reached. This latter regime is characterized by a positive surface charge, when a negative charge was expected. At E0 > Ec, and for low J0, the detailed monitoring of the charge kinetic of MgO (1 1 0) at high primary energy E0 = 30 keV, permit to show that the combined effect of the increased negative surface potential during irradiation and extractor field below the surface of MgO fact that lnσ undergoes a strong slope failure at the beginning of the injection and stabilizes at a value much less than zero leading to the formation of an electrostatic mirror. At high J0, the consequences of the charge accumulation are violent and a breakdown phenomenon is observed
Axial Force at the Vessel Bottom Induced by Axial Impellers
I. Fořt; P. Hasal; A. Paglianti; F. Magelli
2008-01-01
This paper deals with the axial force affecting the flat bottom of a cylindrical stirred vessel. The vessel is equipped with four radial baffles and is stirred with a four 45° pitched blade impeller pumping downwards. The set of pressure transducers is located along the whole radius of the flat bottom between two radial baffles. The radial distribution of the dynamic pressures indicated by the transducers is measured in dependence on the impeller off-bottom clearance and impeller speed.It fol...
DEFF Research Database (Denmark)
van Leeuwen, Theo; Djonov, Emilia
After discussing broad cultural drivers behind the development of kinetic typography, the chapter outlines an approach to analysing kinetic typography which is based on Halliday's theory of transitivity, as applied by Kress and Van Leeuwen to visual images.......After discussing broad cultural drivers behind the development of kinetic typography, the chapter outlines an approach to analysing kinetic typography which is based on Halliday's theory of transitivity, as applied by Kress and Van Leeuwen to visual images....