N-representability of the Jastrow wave function pair density of the lowest-order.
Higuchi, Katsuhiko; Higuchi, Masahiko
2017-08-08
Conditions for the N-representability of the pair density (PD) are needed for the development of the PD functional theory. We derive sufficient conditions for the N-representability of the PD that is calculated from the Jastrow wave function within the lowest order. These conditions are used as the constraints on the correlation function of the Jastrow wave function. A concrete procedure to search the suitable correlation function is also presented.
Three-point Green's function of massless QED in position space to lowest order
International Nuclear Information System (INIS)
Mitra, Indrajit
2009-01-01
The transverse part of the three-point Green's function of massless QED is determined to the lowest order in position space. Taken together with the evaluation of the longitudinal part in Mitra (2008) (J. Phys. A: Math. Theor. 41 315401), this gives a relation for QED which is analogous to the star-triangle relation. We relate our result to conformal-invariant three-point functions
Lowest-order corrections to the RPA polarizability and GW self-energy of a semiconducting wire
Groot, de H.J.; Ummels, R.T.M.; Bobbert, P.A.; van Haeringen, W.
1996-01-01
We present the results of the addition of lowest-order vertex and self-consistency corrections to the RPA polarizability and the GW self-energy for a semiconducting wire. It is found that, when starting from a local density approximation zeroth-order Green function and systematically including these
International Nuclear Information System (INIS)
Pettersen, G.; Oestgaard, E.
1988-01-01
The ground-state energy of solid hydrogen and deuterium is calculated by means of a modified variational lowest order constrained-variation (LOCV) method. Both fcc and hcp H 2 and D 2 are considered, and the calculations are done for five different two-body potentials. For solid H 2 we obtain theoretical results for the ground-state binding energy per particle from -74.9 K at an equilibrium particle density of 0.700 σ -3 or a molar volume of 22.3 cm 3 /mole to -91.3 K at a particle density of 0.725 σ -3 or a molar volume of 21.5 cm 3 /mole, where σ = 2.958 A. The corresponding experimental result is -92.3 K at a particle density of 0.688 σ -3 or a molar volume of 22.7 cm 3 /mole. For solid D 2 we obtain theoretical results for the ground-state binding energy per particle from -125.7 K at an equilibrium particle density of 0.830 σ -3 or a molar volume of 18.8 cm 3 /mole to -140.1 K at a particle density of 0.843 σ -3 or a molar volume of 18.5 cm 3 /mole. The corresponding experimental result is -137.9 K at a particle density of 0.797 σ -3 or a molar volume of 19.6 cm 3 /mole
Lowest-order constrained variational method for simple many-fermion systems
International Nuclear Information System (INIS)
Alexandrov, I.; Moszkowski, S.A.; Wong, C.W.
1975-01-01
The authors study the potential energy of many-fermion systems calculated by the lowest-order constrained variational (LOCV) method of Pandharipande. Two simple two-body interactions are used. For a simple hard-core potential in a dilute Fermi gas, they find that the Huang-Yang exclusion correction can be used to determine a healing distance. The result is close to the older Pandharipande prescription for the healing distance. For a hard core plus attractive exponential potential, the LOCV result agrees closely with the lowest-order separation method of Moszkowski and Scott. They find that the LOCV result has a shallow minimum as a function of the healing distance at the Moszkowski-Scott separation distance. The significance of the absence of a Brueckner dispersion correction in the LOCV result is discussed. (Auth.)
Lowest order Virtual Element approximation of magnetostatic problems
Beirão da Veiga, L.; Brezzi, F.; Dassi, F.; Marini, L. D.; Russo, A.
2018-04-01
We give here a simplified presentation of the lowest order Serendipity Virtual Element method, and show its use for the numerical solution of linear magneto-static problems in three dimensions. The method can be applied to very general decompositions of the computational domain (as is natural for Virtual Element Methods) and uses as unknowns the (constant) tangential component of the magnetic field $\\mathbf{H}$ on each edge, and the vertex values of the Lagrange multiplier $p$ (used to enforce the solenoidality of the magnetic induction $\\mathbf{B}=\\mu\\mathbf{H}$). In this respect the method can be seen as the natural generalization of the lowest order Edge Finite Element Method (the so-called "first kind N\\'ed\\'elec" elements) to polyhedra of almost arbitrary shape, and as we show on some numerical examples it exhibits very good accuracy (for being a lowest order element) and excellent robustness with respect to distortions.
Lowest-order average effect of turbulence on atmospheric profiles derived from radio occultation
International Nuclear Information System (INIS)
Eshleman, V.R.; Haugstad, B.S.
1977-01-01
Turbulence in planetary atmospheres and ionospheres causes changes in angles of refraction of radio waves used in occultation experiments. Atmospheric temperature and pressure profiles, and ionospheric electron concentration profiles, derived from radio occultation measurements of Doppler frequency contain errors due to such angular offsets. The lowest-order average errors are derived from a geometrical-optics treatment of the radio-wave phase advance caused by the addition of uniform turbulence to an initially homogeneous medium. It is concluded that the average profile errors are small and that precise Doppler frequency measurements at two or more wavelengths could be used to help determine characteristics of the turbulence, as well as accuracy limits and possible correction terms for the profiles. However, a more detailed study of both frequency and intensity characteristics in radio and optical occultation measurements of turbulent planetary atmospheres and ionospheres is required to realize the full potential of such measurements
International Nuclear Information System (INIS)
Pettersen, G.; Ostgaard, E.
1988-01-01
The pressure and the compressibility of solid H 2 and D 2 are obtained from ground-state energies calculated by means of a modified variational lowest order constrained-variation (LOCV) method. Both fcc and hcp structures are considered, but results are given for the fcc structure only. The pressure and the compressibility are calculated or estimated from the dependence of the ground-state energy on density or molar volume, generally in a density region of 0.65σ -3 to 1.3σ -3 , corresponding to a molar volume of 0.65σ -3 to 1.3σ -3 , corresponding to a molar volume of 12-24 cm 3 mole, where σ = 2.958 angstrom, and the calculations are done for five different two-body potentials. Theoretical results for the pressure are 340-460 atm for solid H 2 at a particle density of 0.82σ -3 or a molar volume of 19 cm 3 /mole, and 370-490 atm for solid 4 He at a particle density of 0.92σ -3 or a molar volume of 17 cm 3 /mole. The corresponding experimental results are 650 and 700 atm, respectively. Theoretical results for the compressibility are 210 times 10 -6 to 260 times 10 -6 atm -1 for solid H 2 at a particle density of 0.82σ -3 or a molar volume of 19 cm 3 /mole, and 150 times 10 -6 to 180 times 10 -6 atm -1 for solid D 2 at a particle density of 0.92σ -3 or a molar volume of 17 cm 3 mole. The corresponding experimental results are 180 times 10 -6 and 140 times 10 -6 atm -1 , respectively. The agreement with experimental results is better for higher densities
Numerical simulation of lowest-order short-crested wave instabilities
DEFF Research Database (Denmark)
Fuhrman, David R.; Madsen, Per A.; Bingham, Harry
2006-01-01
instabilities. These correctly lead to well-known (nearly symmetric) recurrence cycles below a previously established breaking threshold steepness, and to an asymmetric evolution (characterized by a permanent transfer of energy to the lower side-band) above this threshold, with dissipation from a smoothing...... that the unstable evolution of these initially three-dimensional waves leads to an asymmetric evolution, even for weakly nonlinear cases presumably well below breaking. This is characterized by an energy transfer to the lower side-band, which is also accompanied by a similar transfer to more distant upper side......-bands. At larger steepness, the evolution leads to a permanent downshift of both the mean and peak frequencies, driven in part by dissipation, effectively breaking the quasi-recurrence cycle. A single case involving a class Ib short-crested wave instability at relatively large steepness is also considered, which...
International Nuclear Information System (INIS)
Bellorin, Jorge; Restuccia, Alvaro
2011-01-01
We perform the Hamiltonian analysis for the lowest-order effective action, up to second order in derivatives, of the complete Horava theory. The model includes the invariant terms that depend on ∂ i lnN proposed by Blas, Pujolas, and Sibiryakov. We show that the algebra of constraints closes. The Hamiltonian constraint is of second-class behavior and it can be regarded as an elliptic partial differential equation for N. The linearized version of this equation is a Poisson equation for N that can be solved consistently. The preservation in time of the Hamiltonian constraint yields an equation that can be consistently solved for a Lagrange multiplier of the theory. The model has six propagating degrees of freedom in the phase space, corresponding to three even physical modes. When compared with the λR model studied by us in a previous paper, it lacks two second-class constraints, which leads to the extra even mode.
International Nuclear Information System (INIS)
Shumeiko, N.M.; Timoshin, S.I.
1991-01-01
Compact formulae for a total 1-loop electromagnetic corrections, including the contribution of electromagnetic hadron effects to the deep inelastic scattering of polarized leptons on polarized nucleons in the quark-parton model have been obtained. The cases of longitudinal and transverse nucleon polarization are considered in detail. A thorough numerical calculation of corrections to cross sections and polarization asymmetries at muon (electron) energies over the range of 200-2000 GeV (10-16 GeV) has been made. It has been established that the contribution of corrections to the hadron current considerably affects the behaviour of longitudinal asymmetry. A satisfactory agreement is found between the model calculations of corrections to the lepton current and the phenomenological calculation results, which makes it possible to find the total 1-loop correction within the framework of a common approach. (Author)
Directory of Open Access Journals (Sweden)
Dongbo Zhang
2016-08-01
Full Text Available In this work, we applied a robust and fully air-coupled method to investigate the propagation of the lowest-order antisymmetric Lamb (A0 mode in both a stubbed and an air-drilled phononic-crystal (PC plate. By measuring simply the radiative acoustic waves of A0 mode close to the plate surface, we observed the band gaps for the stubbed PC plate caused by either the local resonance or the Bragg scattering, in frequency ranges in good agreement with theoretical predictions. We measured then the complete band gap of A0 mode for the air-drilled PC plate, in good agreement with the band structures. Finally, we compared the measurements made using the air-coupled method with those obtained by the laser ultrasonic technique.
Energy Technology Data Exchange (ETDEWEB)
Zhang, Dongbo; Zhao, Jinfeng, E-mail: jinfeng.zhao@tongji.edu.cn; Li, Libing; Pan, Yongdong; Zhong, Zheng [School of Aerospace Engineering and Applied Mechanics, Tongji University, 100 Zhangwu Road, 200092, Shanghai (China); Bonello, Bernard [CNRS, UMR 7588, Institut des NanoSciences de Paris, F-75005, Paris (France); Wei, Jianxin [State Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum, 18 Xuefu Road, 102249, Pekin (China)
2016-08-15
In this work, we applied a robust and fully air-coupled method to investigate the propagation of the lowest-order antisymmetric Lamb (A{sub 0}) mode in both a stubbed and an air-drilled phononic-crystal (PC) plate. By measuring simply the radiative acoustic waves of A{sub 0} mode close to the plate surface, we observed the band gaps for the stubbed PC plate caused by either the local resonance or the Bragg scattering, in frequency ranges in good agreement with theoretical predictions. We measured then the complete band gap of A{sub 0} mode for the air-drilled PC plate, in good agreement with the band structures. Finally, we compared the measurements made using the air-coupled method with those obtained by the laser ultrasonic technique.
Measurement of the nucleon structure function using high energy muons
International Nuclear Information System (INIS)
Meyers, P.D.
1983-12-01
We have measured the inclusive deep inelastic scattering of muons on nucleons in iron using beams of 93 and 215 GeV muons. To perform this measurement, we have built and operated the Multimuon Spectrometer (MMS) in the muon beam at Fermilab. The MMS is a magnetized iron target/spectrometer/calorimeter which provides 5.61 kg/cm 2 of target, 9% momentum resolution on scattered muons, and a direct measure of total hadronic energy with resolution sigma/sub nu/ = 1.4√nu(GeV). In the distributed target, the average beam energies at the interaction are 88.0 and 209 GeV. Using the known form of the radiatively-corrected electromagnetic cross section, we extract the structure function F 2 (x,Q 2 ) with a typical precision of 2% over the range 5 2 2 /c 2 . We compare our measurements to the predictions of lowest order quantum chromodynamics (QCD) and find a best fit value of the QCD scale parameter Λ/sub LO/ = 230 +- 40/sup stat/ +- 80/sup syst/ MeV/c, assuming R = 0 and without applying Fermi motion corrections. Comparing the cross sections at the two beam energies, we measure R = -0.06 +- 0.06/sup stat/ +- 0.11/sup syst/. Our measurements show qualitative agreement with QCD, but quantitative comparison is hampered by phenomenological uncertainties. The experimental situation is quite good, with substantial agreement between our measurements and those of others. 86 references
Nonlocal kinetic energy functionals by functional integration
Mi, Wenhui; Genova, Alessandro; Pavanello, Michele
2018-05-01
Since the seminal studies of Thomas and Fermi, researchers in the Density-Functional Theory (DFT) community are searching for accurate electron density functionals. Arguably, the toughest functional to approximate is the noninteracting kinetic energy, Ts[ρ], the subject of this work. The typical paradigm is to first approximate the energy functional and then take its functional derivative, δ/Ts[ρ ] δ ρ (r ) , yielding a potential that can be used in orbital-free DFT or subsystem DFT simulations. Here, this paradigm is challenged by constructing the potential from the second-functional derivative via functional integration. A new nonlocal functional for Ts[ρ] is prescribed [which we dub Mi-Genova-Pavanello (MGP)] having a density independent kernel. MGP is constructed to satisfy three exact conditions: (1) a nonzero "Kinetic electron" arising from a nonzero exchange hole; (2) the second functional derivative must reduce to the inverse Lindhard function in the limit of homogenous densities; (3) the potential is derived from functional integration of the second functional derivative. Pilot calculations show that MGP is capable of reproducing accurate equilibrium volumes, bulk moduli, total energy, and electron densities for metallic (body-centered cubic, face-centered cubic) and semiconducting (crystal diamond) phases of silicon as well as of III-V semiconductors. The MGP functional is found to be numerically stable typically reaching self-consistency within 12 iterations of a truncated Newton minimization algorithm. MGP's computational cost and memory requirements are low and comparable to the Wang-Teter nonlocal functional or any generalized gradient approximation functional.
Microscopically Based Nuclear Energy Functionals
International Nuclear Information System (INIS)
Bogner, S. K.
2009-01-01
A major goal of the SciDAC project 'Building a Universal Nuclear Energy Density Functional' is to develop next-generation nuclear energy density functionals that give controlled extrapolations away from stability with improved performance across the mass table. One strategy is to identify missing physics in phenomenological Skyrme functionals based on our understanding of the underlying internucleon interactions and microscopic many-body theory. In this contribution, I describe ongoing efforts to use the density matrix expansion of Negele and Vautherin to incorporate missing finite-range effects from the underlying two- and three-nucleon interactions into phenomenological Skyrme functionals.
Measurement of the nucleon structure function using high energy muons
Energy Technology Data Exchange (ETDEWEB)
Meyers, P.D.
1983-12-01
We have measured the inclusive deep inelastic scattering of muons on nucleons in iron using beams of 93 and 215 GeV muons. To perform this measurement, we have built and operated the Multimuon Spectrometer (MMS) in the muon beam at Fermilab. The MMS is a magnetized iron target/spectrometer/calorimeter which provides 5.61 kg/cm/sup 2/ of target, 9% momentum resolution on scattered muons, and a direct measure of total hadronic energy with resolution sigma/sub nu/ = 1.4..sqrt..nu(GeV). In the distributed target, the average beam energies at the interaction are 88.0 and 209 GeV. Using the known form of the radiatively-corrected electromagnetic cross section, we extract the structure function F/sub 2/(x,Q/sup 2/) with a typical precision of 2% over the range 5 < Q/sup 2/ < 200 GeV/sup 2//c/sup 2/. We compare our measurements to the predictions of lowest order quantum chromodynamics (QCD) and find a best fit value of the QCD scale parameter ..lambda../sub LO/ = 230 +- 40/sup stat/ +- 80/sup syst/ MeV/c, assuming R = 0 and without applying Fermi motion corrections. Comparing the cross sections at the two beam energies, we measure R = -0.06 +- 0.06/sup stat/ +- 0.11/sup syst/. Our measurements show qualitative agreement with QCD, but quantitative comparison is hampered by phenomenological uncertainties. The experimental situation is quite good, with substantial agreement between our measurements and those of others. 86 references.
Energy functions for regularization algorithms
Delingette, H.; Hebert, M.; Ikeuchi, K.
1991-01-01
Regularization techniques are widely used for inverse problem solving in computer vision such as surface reconstruction, edge detection, or optical flow estimation. Energy functions used for regularization algorithms measure how smooth a curve or surface is, and to render acceptable solutions these energies must verify certain properties such as invariance with Euclidean transformations or invariance with parameterization. The notion of smoothness energy is extended here to the notion of a differential stabilizer, and it is shown that to void the systematic underestimation of undercurvature for planar curve fitting, it is necessary that circles be the curves of maximum smoothness. A set of stabilizers is proposed that meet this condition as well as invariance with rotation and parameterization.
Density dependence of the nuclear energy-density functional
Papakonstantinou, Panagiota; Park, Tae-Sun; Lim, Yeunhwan; Hyun, Chang Ho
2018-01-01
Background: The explicit density dependence in the coupling coefficients entering the nonrelativistic nuclear energy-density functional (EDF) is understood to encode effects of three-nucleon forces and dynamical correlations. The necessity for the density-dependent coupling coefficients to assume the form of a preferably small fractional power of the density ρ is empirical and the power is often chosen arbitrarily. Consequently, precision-oriented parametrizations risk overfitting in the regime of saturation and extrapolations in dilute or dense matter may lose predictive power. Purpose: Beginning with the observation that the Fermi momentum kF, i.e., the cubic root of the density, is a key variable in the description of Fermi systems, we first wish to examine if a power hierarchy in a kF expansion can be inferred from the properties of homogeneous matter in a domain of densities, which is relevant for nuclear structure and neutron stars. For subsequent applications we want to determine a functional that is of good quality but not overtrained. Method: For the EDF, we fit systematically polynomial and other functions of ρ1 /3 to existing microscopic, variational calculations of the energy of symmetric and pure neutron matter (pseudodata) and analyze the behavior of the fits. We select a form and a set of parameters, which we found robust, and examine the parameters' naturalness and the quality of resulting extrapolations. Results: A statistical analysis confirms that low-order terms such as ρ1 /3 and ρ2 /3 are the most relevant ones in the nuclear EDF beyond lowest order. It also hints at a different power hierarchy for symmetric vs. pure neutron matter, supporting the need for more than one density-dependent term in nonrelativistic EDFs. The functional we propose easily accommodates known or adopted properties of nuclear matter near saturation. More importantly, upon extrapolation to dilute or asymmetric matter, it reproduces a range of existing microscopic
Minimal nuclear energy density functional
Bulgac, Aurel; Forbes, Michael McNeil; Jin, Shi; Perez, Rodrigo Navarro; Schunck, Nicolas
2018-04-01
We present a minimal nuclear energy density functional (NEDF) called "SeaLL1" that has the smallest number of possible phenomenological parameters to date. SeaLL1 is defined by seven significant phenomenological parameters, each related to a specific nuclear property. It describes the nuclear masses of even-even nuclei with a mean energy error of 0.97 MeV and a standard deviation of 1.46 MeV , two-neutron and two-proton separation energies with rms errors of 0.69 MeV and 0.59 MeV respectively, and the charge radii of 345 even-even nuclei with a mean error ɛr=0.022 fm and a standard deviation σr=0.025 fm . SeaLL1 incorporates constraints on the equation of state (EoS) of pure neutron matter from quantum Monte Carlo calculations with chiral effective field theory two-body (NN ) interactions at the next-to-next-to-next-to leading order (N3LO) level and three-body (NNN ) interactions at the next-to-next-to leading order (N2LO) level. Two of the seven parameters are related to the saturation density and the energy per particle of the homogeneous symmetric nuclear matter, one is related to the nuclear surface tension, two are related to the symmetry energy and its density dependence, one is related to the strength of the spin-orbit interaction, and one is the coupling constant of the pairing interaction. We identify additional phenomenological parameters that have little effect on ground-state properties but can be used to fine-tune features such as the Thomas-Reiche-Kuhn sum rule, the excitation energy of the giant dipole and Gamow-Teller resonances, the static dipole electric polarizability, and the neutron skin thickness.
The complete lowest order chiral Lagrangian from a little box
International Nuclear Information System (INIS)
DeGrand, T.; Schaefer, S.
2007-09-01
We recently performed a pilot study determining the parameters of the leading order chiral Lagrangian from distributions of the eigenvalues of a quenched Dirac operator coupled to an imaginary isospin chemical potential. (orig.)
Parameters of the lowest order chiral Lagrangian from fermion eigenvalues
International Nuclear Information System (INIS)
DeGrand, T.; Schaefer, S.
2007-08-01
Recent advances in Random Matrix Theory enable one to determine the pseudoscalar decay constant from the response of eigenmodes of quenched fermions to an imaginary isospin chemical potential. We perform a pilot test of this idea, from simulations with two flavors of dynamical overlap fermions. (orig.)
Approximate Schur complement preconditioning of the lowest order nodal discretizations
Energy Technology Data Exchange (ETDEWEB)
Moulton, J.D.; Ascher, U.M. [Univ. of British Columbia, Vancouver, British Columbia (Canada); Morel, J.E. [Los Alamos National Lab., NM (United States)
1996-12-31
Particular classes of nodal methods and mixed hybrid finite element methods lead to equivalent, robust and accurate discretizations of 2nd order elliptic PDEs. However, widespread popularity of these discretizations has been hindered by the awkward linear systems which result. The present work exploits this awkwardness, which provides a natural partitioning of the linear system, by defining two optimal preconditioners based on approximate Schur complements. Central to the optimal performance of these preconditioners is their sparsity structure which is compatible with Dendy`s black box multigrid code.
Potential energy function of CN-
Czech Academy of Sciences Publication Activity Database
Špirko, Vladimír; Polák, Rudolf
2008-01-01
Roč. 248, č. 1 (2008), s. 77-80 ISSN 0022-2852 R&D Projects: GA MŠk LC512; GA AV ČR IAA400550511; GA AV ČR IAA400400504 Institutional research plan: CEZ:AV0Z40550506; CEZ:AV0Z40400503 Keywords : potential energy curve * fundamental transition * spectroscopic constants Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.636, year: 2008
Directory of Open Access Journals (Sweden)
Ron Tolmie
2014-11-01
Full Text Available Heat can be collected from local energy sources and concentrated into a relatively small volume, and at a useful working temperature, by using a heat pump as the concentrator. That heat can be stored and utilized at a later date for applications like space heating. The process is doing two things at the same time: storing heat and shifting the power demand. The concentration step can be done at night when there is normally a surplus of power and its timing can be directly controlled by the power grid operator to ensure that the power consumption occurs only when adequate power is available. The sources of heat can be the summer air, the heat extracted from buildings by their cooling systems, natural heat from the ground or solar heat, all of which are free, abundant and readily accessible. Such systems can meet the thermal needs of buildings while at the same time stabilizing the grid power demand, thus reducing the need for using fossil-fuelled peaking power generators. The heat pump maintains the temperature of the periphery at the ambient ground temperature so very little energy is lost during storage.
Universal Nuclear Energy Density Functional
Energy Technology Data Exchange (ETDEWEB)
Carlson, Joseph; Furnstahl, Richard; Horoi, Mihai; Lusk, Rusty; Nazarewicz, Witold; Ng, Esmond; Thompson, Ian; Vary, James
2012-12-01
An understanding of the properties of atomic nuclei is crucial for a complete nuclear theory, for element formation, for properties of stars, and for present and future energy and defense applications. During the period of Dec. 1 2006 – Jun. 30, 2012, the UNEDF collaboration carried out a comprehensive study of all nuclei, based on the most accurate knowledge of the strong nuclear interaction, the most reliable theoretical approaches, the most advanced algorithms, and extensive computational resources, with a view towards scaling to the petaflop platforms and beyond. Until recently such an undertaking was hard to imagine, and even at the present time such an ambitious endeavor would be far beyond what a single researcher or a traditional research group could carry out.
Building a universal nuclear energy density functional
International Nuclear Information System (INIS)
Bertsch, G F
2007-01-01
This talk describes a new project in SciDAC II in the area of low-energy nuclear physics. The motivation and goals of the SciDAC are presented as well as an outline of the theoretical and computational methodology that will be employed. An important motivation is to have more accurate and reliable predictions of nuclear properties including their binding energies and low-energy reaction rates. The theoretical basis is provided by density functional theory, which the only available theory that can be systematically applied to all nuclei. However, other methodologies based on wave function methods are needed to refine the functionals and to make applications to dynamic processes
Fermi-Dirac function and energy gap
Bondarev, Boris
2013-01-01
Medium field method is applied for studying valence electron behavior in metals. When different wave-vector electrons are attracted at low temperatures, distribution function gets discontinued. As a result, a specific energy gap occurs.
Economic modelling of energy services: Rectifying misspecified energy demand functions
International Nuclear Information System (INIS)
Hunt, Lester C.; Ryan, David L.
2015-01-01
estimation of an aggregate energy demand function for the UK with data over the period 1960–2011. - Highlights: • Introduces explicit modelling of demands for energy services • Derives estimable energy demand equations from energy service demands • Demonstrates the implicit misspecification with typical energy demand equations • Empirical implementation using aggregate and individual energy source data • Illustrative empirical example using UK data and energy efficiency modelling
Nonlocal kinetic-energy-density functionals
International Nuclear Information System (INIS)
Garcia-Gonzalez, P.; Alvarellos, J.E.; Chacon, E.
1996-01-01
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
Functional materials for energy-efficient buildings
Ebert, H.-P.
2015-08-01
The substantial improving of the energy efficiency is essential to meet the ambitious energy goals of the EU. About 40% of the European energy consumption belongs to the building sector. Therefore the reduction of the energy demand of the existing building stock is one of the key measures to deliver a substantial contribution to reduce CO2-emissions of our society. Buildings of the future have to be efficient in respect to energy consumption for construction and operation. Current research activities are focused on the development of functional materials with outstanding thermal and optical properties to provide, for example, slim thermally superinsulated facades, highly integrated heat storage systems or adaptive building components. In this context it is important to consider buildings as entities which fulfill energy and comfort claims as well as aesthetic aspects of a sustainable architecture.
Functional materials for energy-efficient buildings
Directory of Open Access Journals (Sweden)
Ebert H.-P
2015-01-01
Full Text Available The substantial improving of the energy efficiency is essential to meet the ambitious energy goals of the EU. About 40% of the European energy consumption belongs to the building sector. Therefore the reduction of the energy demand of the existing building stock is one of the key measures to deliver a substantial contribution to reduce CO2-emissions of our society. Buildings of the future have to be efficient in respect to energy consumption for construction and operation. Current research activities are focused on the development of functional materials with outstanding thermal and optical properties to provide, for example, slim thermally superinsulated facades, highly integrated heat storage systems or adaptive building components. In this context it is important to consider buildings as entities which fulfill energy and comfort claims as well as aesthetic aspects of a sustainable architecture.
SURFACE SYMMETRY ENERGY OF NUCLEAR ENERGY DENSITY FUNCTIONALS
Energy Technology Data Exchange (ETDEWEB)
Nikolov, N; Schunck, N; Nazarewicz, W; Bender, M; Pei, J
2010-12-20
We study the bulk deformation properties of the Skyrme nuclear energy density functionals. Following simple arguments based on the leptodermous expansion and liquid drop model, we apply the nuclear density functional theory to assess the role of the surface symmetry energy in nuclei. To this end, we validate the commonly used functional parametrizations against the data on excitation energies of superdeformed band-heads in Hg and Pb isotopes, and fission isomers in actinide nuclei. After subtracting shell effects, the results of our self-consistent calculations are consistent with macroscopic arguments and indicate that experimental data on strongly deformed configurations in neutron-rich nuclei are essential for optimizing future nuclear energy density functionals. The resulting survey provides a useful benchmark for further theoretical improvements. Unlike in nuclei close to the stability valley, whose macroscopic deformability hangs on the balance of surface and Coulomb terms, the deformability of neutron-rich nuclei strongly depends on the surface-symmetry energy; hence, its proper determination is crucial for the stability of deformed phases of the neutron-rich matter and description of fission rates for r-process nucleosynthesis.
Energy harvesting with functional materials and microsystems
Bhaskaran, Madhu; Iniewski, Krzysztof
2013-01-01
For decades, people have searched for ways to harvest energy from natural sources. Lately, a desire to address the issue of global warming and climate change has popularized solar or photovoltaic technology, while piezoelectric technology is being developed to power handheld devices without batteries, and thermoelectric technology is being explored to convert wasted heat, such as in automobile engine combustion, into electricity. Featuring contributions from international researchers in both academics and industry, Energy Harvesting with Functional Materials and Microsystems explains the growi
Damage energy functions for compounds and alloys
International Nuclear Information System (INIS)
Parkin, D.M.; Coulter, C.A.
1977-01-01
The concept of the damage energy of an energetic primary knock-on atom in a material is a central component in the procedure used to calculate dpa for metals exposed to neutron and charged particle radiation. Coefficients for analytic fits to the calculated damage energy functions are given for Al 2 O 3 , Si 3 N 4 , Y 2 O 3 , and NbTi. Damage efficiencies are given for Al 2 O 3
Neuroenergetics: How energy constraints shape brain function
CERN. Geneva
2016-01-01
The nervous system consumes a disproportionate fraction of the resting body’s energy production. In humans, the brain represents 2% of the body’s mass, yet it accounts for ~20% of the total oxygen consumption. Expansion in the size of the brain relative to the body and an increase in the number of connections between neurons during evolution underpin our cognitive powers and are responsible for our brains’ high metabolic rate. The molecules at the center of cellular energy metabolism also act as intercellular signals and constitute an important communication pathway, coordinating for instance the immune surveillance of the brain. Despite the significance of energy consumption in the nervous system, how energy constrains and shapes brain function is often under appreciated. I will illustrate the importance of brain energetics and metabolism with two examples from my recent work. First, I will show how the brain trades information for energy savings in the visual pathway. Indeed, a significant fraction ...
dd →3 Hen Reaction at Intermediate Energies
International Nuclear Information System (INIS)
Ladygina, N. B.
2012-01-01
The dd → 3 Hen reaction is considered at the energies between 200 and 520 MeV. The Alt-Grassberger-Sandhas equations are iterated up to the lowest order terms over the nucleon-nucleon t-matrix. The parameterized 3He wave function including five components is used. The angular dependence of the differential cross section and energy dependence of tensor analyzing power T 20 at the zero scattering angle are presented in comparison with the experimental data. (author)
Quark condensate contributions to the gluon self-energy and the ρ meson sum rule
International Nuclear Information System (INIS)
Steele, T.G.
1989-01-01
The operator-product expansion will be employed to obtain the lowest-order, quark condensate component of both the gluon self-energy and the ρ meson correlation function to all orders in the quark mass parameter. Field-theoretic aspects of the self-energy and correlation function will be considered, and physical effects to the quark condensate upon gluon mass generation will be examined. (orig.)
Functional data analysis of sleeping energy expenditure
Adequate sleep is crucial during childhood for metabolic health, and physical and cognitive development. Inadequate sleep can disrupt metabolic homeostasis and alter sleeping energy expenditure (SEE). Functional data analysis methods were applied to SEE data to elucidate the population structure of ...
Analysis of the Bogoliubov free energy functional
DEFF Research Database (Denmark)
Reuvers, Robin
In this thesis, we analyse a variational reformulation of the Bogoliubov approximation that is used to describe weakly-interacting translationally-invariant Bose gases. For the resulting model, the `Bogoliubov free energy functional', we demonstrate existence of minimizers as well as the presence...
Electron energy-distribution functions in gases
International Nuclear Information System (INIS)
Pitchford, L.C.
1981-01-01
Numerical calculation of the electron energy distribution functions in the regime of drift tube experiments is discussed. The discussion is limited to constant applied fields and values of E/N (ratio of electric field strength to neutral density) low enough that electron growth due to ionization can be neglected
Functional derivative of noninteracting kinetic energy density functional
International Nuclear Information System (INIS)
Liu Shubin; Ayers, Paul W.
2004-01-01
Proofs from different theoretical frameworks, namely, the Hohenbergh-Kohn theorems, the Kohn-Sham scheme, and the first-order density matrix representation, have been presented in this paper to show that the functional derivative of the noninteracting kinetic energy density functional can uniquely be expressed as the negative of the Kohn-Sham effective potential, arbitrary only to an additive orbital-independent constant. Key points leading to the current result as well as confusion about the quantity in the literature are briefly discussed
Functional Carbon Materials for Electrochemical Energy Storage
Zhou, Huihui
The ability to harvest and convert solar energy has been associated with the evolution of human civilization. The increasing consumption of fossil fuels since the industrial revolution, however, has brought to concerns in ecological deterioration and depletion of the fossil fuels. Facing these challenges, humankind is forced to seek for clean, sustainable and renewable energy resources, such as biofuels, hydraulic power, wind power, geothermal energy and other kinds of alternative energies. However, most alternative energy sources, generally in the form of electrical energy, could not be made available on a continuous basis. It is, therefore, essential to store such energy into chemical energy, which are portable and various applications. In this context, electrochemical energy-storage devices hold great promises towards this goal. The most common electrochemical energy-storage devices are electrochemical capacitors (ECs, also called supercapacitors) and batteries. In comparison to batteries, ECs posses high power density, high efficiency, long cycling life and low cost. ECs commonly utilize carbon as both (symmetric) or one of the electrodes (asymmetric), of which their performance is generally limited by the capacitance of the carbon electrodes. Therefore, developing better carbon materials with high energy density has been emerging as one the most essential challenges in the field. The primary objective of this dissertation is to design and synthesize functional carbon materials with high energy density at both aqueous and organic electrolyte systems. The energy density (E) of ECs are governed by E = CV 2/2, where C is the total capacitance and V is the voltage of the devices. Carbon electrodes with high capacitance and high working voltage should lead to high energy density. In the first part of this thesis, a new class of nanoporous carbons were synthesized for symmetric supercapacitors using aqueous Li2SO4 as the electrolyte. A unique precursor was adopted to
Functional materials discovery using energy-structure-function maps.
Pulido, Angeles; Chen, Linjiang; Kaczorowski, Tomasz; Holden, Daniel; Little, Marc A; Chong, Samantha Y; Slater, Benjamin J; McMahon, David P; Bonillo, Baltasar; Stackhouse, Chloe J; Stephenson, Andrew; Kane, Christopher M; Clowes, Rob; Hasell, Tom; Cooper, Andrew I; Day, Graeme M
2017-03-30
Molecular crystals cannot be designed in the same manner as macroscopic objects, because they do not assemble according to simple, intuitive rules. Their structures result from the balance of many weak interactions, rather than from the strong and predictable bonding patterns found in metal-organic frameworks and covalent organic frameworks. Hence, design strategies that assume a topology or other structural blueprint will often fail. Here we combine computational crystal structure prediction and property prediction to build energy-structure-function maps that describe the possible structures and properties that are available to a candidate molecule. Using these maps, we identify a highly porous solid, which has the lowest density reported for a molecular crystal so far. Both the structure of the crystal and its physical properties, such as methane storage capacity and guest-molecule selectivity, are predicted using the molecular structure as the only input. More generally, energy-structure-function maps could be used to guide the experimental discovery of materials with any target function that can be calculated from predicted crystal structures, such as electronic structure or mechanical properties.
The Bogoliubov free energy functional II
DEFF Research Database (Denmark)
Napiórkowski, Marcin; Reuvers, Robin; Solovej, Jan Philip
2018-01-01
We analyse the canonical Bogoliubov free energy functional at low temperatures in the dilute limit. We prove existence of a first order phase transition and, in the limit $a_0\\to a$, we determine the critical temperature to be $T_{\\rm{c}}=T_{\\rm{fc}}(1+1.49(\\rho^{1/3}a))$ to leading order. Here, $T......_{\\rm{fc}}$ is the critical temperature of the free Bose gas, $\\rho$ is the density of the gas, $a$ is the scattering length of the pair-interaction potential $V$, and $a_0=(8\\pi)^{-1}\\widehat{V}(0)$ its first order approximation. We also prove asymptotic expansions for the free energy. In particular, we recover the Lee...
Functional data analysis of sleeping energy expenditure.
Lee, Jong Soo; Zakeri, Issa F; Butte, Nancy F
2017-01-01
Adequate sleep is crucial during childhood for metabolic health, and physical and cognitive development. Inadequate sleep can disrupt metabolic homeostasis and alter sleeping energy expenditure (SEE). Functional data analysis methods were applied to SEE data to elucidate the population structure of SEE and to discriminate SEE between obese and non-obese children. Minute-by-minute SEE in 109 children, ages 5-18, was measured in room respiration calorimeters. A smoothing spline method was applied to the calorimetric data to extract the true smoothing function for each subject. Functional principal component analysis was used to capture the important modes of variation of the functional data and to identify differences in SEE patterns. Combinations of functional principal component analysis and classifier algorithm were used to classify SEE. Smoothing effectively removed instrumentation noise inherent in the room calorimeter data, providing more accurate data for analysis of the dynamics of SEE. SEE exhibited declining but subtly undulating patterns throughout the night. Mean SEE was markedly higher in obese than non-obese children, as expected due to their greater body mass. SEE was higher among the obese than non-obese children (p0.1, after post hoc testing). Functional principal component scores for the first two components explained 77.8% of the variance in SEE and also differed between groups (p = 0.037). Logistic regression, support vector machine or random forest classification methods were able to distinguish weight-adjusted SEE between obese and non-obese participants with good classification rates (62-64%). Our results implicate other factors, yet to be uncovered, that affect the weight-adjusted SEE of obese and non-obese children. Functional data analysis revealed differences in the structure of SEE between obese and non-obese children that may contribute to disruption of metabolic homeostasis.
Multi-functional energy plantation; Multifunktionella bioenergiodlingar
Energy Technology Data Exchange (ETDEWEB)
Boerjesson, Paal [Lund Univ. (Sweden). Environmental and Energy Systems Studies; Berndes, Goeran; Fredriksson, Fredrik [Chalmers Univ. of Technology, Goeteborg (Sweden). Dept. of Physical Resource Theory; Kaaberger, Tomas [Ecotraffic, Goeteborg (Sweden)
2002-02-01
There exists a significant potential for utilising perennial energy plantations in protecting and restoring polluted water and land resources in Sweden. By optimising the design, location and management, several additional environmental services could be obtained which will increase the value of the energy plantations, thereby improving future market conditions for biomass. Multi-functional energy plantations (mainly Salix but also energy grass) can be divided into two categories, those designed for dedicated environmental services (e.g. vegetation filters for wastewater and sewage sludge treatment and shelter belts against soil erosion), and those generating more general benefits (e.g. soil carbon accumulation, increased soil fertility, cadmium removal and increased hunting potential). The practical potential of those two categories is estimated to be equivalent to up to 3% and more than 20% of the total Swedish arable land, respectively. The regional conditions of utilising multi-functional plantations vary, however, with the best possibilities in densely populated areas dominated by farmland. The economic value of multi-functional plantations is normally highest for those designed for dedicated environmental services. Purification of wastewater has the highest value, which could exceed the production cost in conventional Salix plantations, followed by treatment of polluted drainage water in vegetation filters and buffer zones (equivalent to more than half of the production cost), recirculation of sewage sludge (around half of the production cost), erosion control (around one fourth) and increased hunting potential (up to 15% of the production cost). The value of increased hunting potential varies due to nearness to larger cities and in which part of Sweden the plantation is located. The economic value of cadmium removal and increased soil fertility is equivalent to a few percent of the production cost, but the value of cadmium removal might increase in the
Balance Function in High-Energy Collisions
International Nuclear Information System (INIS)
Tawfik, A.; Shalaby, Asmaa G.
2015-01-01
Aspects and implications of the balance functions (BF) in high-energy physics are reviewed. The various calculations and measurements depending on different quantities, for example, system size, collisions centrality, and beam energy, are discussed. First, the different definitions including advantages and even short-comings are highlighted. It is found that BF, which are mainly presented in terms of relative rapidity, and relative azimuthal and invariant relative momentum, are sensitive to the interaction centrality but not to the beam energy and can be used in estimating the hadronization time and the hadron-quark phase transition. Furthermore, the quark chemistry can be determined. The chemical evolution of the new-state-of-matter, the quark-gluon plasma, and its temporal-spatial evolution, femtoscopy of two-particle correlations, are accessible. The production time of positive-negative pair of charges can be determined from the widths of BF. Due to the reduction in the diffusion time, narrowed widths refer to delayed hadronization. It is concluded that BF are powerful tools characterizing hadron-quark phase transition and estimating some essential properties
Energy functionals for Calabi-Yau metrics
International Nuclear Information System (INIS)
Headrick, M; Nassar, A
2013-01-01
We identify a set of ''energy'' functionals on the space of metrics in a given Kähler class on a Calabi-Yau manifold, which are bounded below and minimized uniquely on the Ricci-flat metric in that class. Using these functionals, we recast the problem of numerically solving the Einstein equation as an optimization problem. We apply this strategy, using the ''algebraic'' metrics (metrics for which the Kähler potential is given in terms of a polynomial in the projective coordinates), to the Fermat quartic and to a one-parameter family of quintics that includes the Fermat and conifold quintics. We show that this method yields approximations to the Ricci-flat metric that are exponentially accurate in the degree of the polynomial (except at the conifold point, where the convergence is polynomial), and therefore orders of magnitude more accurate than the balanced metrics, previously studied as approximations to the Ricci-flat metric. The method is relatively fast and easy to implement. On the theoretical side, we also show that the functionals can be used to give a heuristic proof of Yau's theorem
Building a Universal Nuclear Energy Density Functional
Energy Technology Data Exchange (ETDEWEB)
Carlson, Joe A. [Michigan State Univ., East Lansing, MI (United States); Furnstahl, Dick; Horoi, Mihai; Lust, Rusty; Nazaewicc, Witek; Ng, Esmond; Thompson, Ian; Vary, James
2012-12-30
During the period of Dec. 1 2006 – Jun. 30, 2012, the UNEDF collaboration carried out a comprehensive study of all nuclei, based on the most accurate knowledge of the strong nuclear interaction, the most reliable theoretical approaches, the most advanced algorithms, and extensive computational resources, with a view towards scaling to the petaflop platforms and beyond. The long-term vision initiated with UNEDF is to arrive at a comprehensive, quantitative, and unified description of nuclei and their reactions, grounded in the fundamental interactions between the constituent nucleons. We seek to replace current phenomenological models of nuclear structure and reactions with a well-founded microscopic theory that delivers maximum predictive power with well-quantified uncertainties. Specifically, the mission of this project has been three-fold: First, to find an optimal energy density functional (EDF) using all our knowledge of the nucleonic Hamiltonian and basic nuclear properties; Second, to apply the EDF theory and its extensions to validate the functional using all the available relevant nuclear structure and reaction data; Third, to apply the validated theory to properties of interest that cannot be measured, in particular the properties needed for reaction theory.
Electroweak splitting functions and high energy showering
Chen, Junmou; Han, Tao; Tweedie, Brock
2017-11-01
We derive the electroweak (EW) collinear splitting functions for the Standard Model, including the massive fermions, gauge bosons and the Higgs boson. We first present the splitting functions in the limit of unbroken SU(2) L × U(1) Y and discuss their general features in the collinear and soft-collinear regimes. These are the leading contributions at a splitting scale ( k T ) far above the EW scale ( v). We then systematically incorporate EW symmetry breaking (EWSB), which leads to the emergence of additional "ultra-collinear" splitting phenomena and naive violations of the Goldstone-boson Equivalence Theorem. We suggest a particularly convenient choice of non-covariant gauge (dubbed "Goldstone Equivalence Gauge") that disentangles the effects of Goldstone bosons and gauge fields in the presence of EWSB, and allows trivial book-keeping of leading power corrections in v/ k T . We implement a comprehensive, practical EW showering scheme based on these splitting functions using a Sudakov evolution formalism. Novel features in the implementation include a complete accounting of ultra-collinear effects, matching between shower and decay, kinematic back-reaction corrections in multi-stage showers, and mixed-state evolution of neutral bosons ( γ/ Z/ h) using density-matrices. We employ the EW showering formalism to study a number of important physical processes at O (1-10 TeV) energies. They include (a) electroweak partons in the initial state as the basis for vector-boson-fusion; (b) the emergence of "weak jets" such as those initiated by transverse gauge bosons, with individual splitting probabilities as large as O (35%); (c) EW showers initiated by top quarks, including Higgs bosons in the final state; (d) the occurrence of O (1) interference effects within EW showers involving the neutral bosons; and (e) EW corrections to new physics processes, as illustrated by production of a heavy vector boson ( W ') and the subsequent showering of its decay products.
Elfwing, Stefan; Uchibe, Eiji; Doya, Kenji
2016-12-01
Free-energy based reinforcement learning (FERL) was proposed for learning in high-dimensional state and action spaces. However, the FERL method does only really work well with binary, or close to binary, state input, where the number of active states is fewer than the number of non-active states. In the FERL method, the value function is approximated by the negative free energy of a restricted Boltzmann machine (RBM). In our earlier study, we demonstrated that the performance and the robustness of the FERL method can be improved by scaling the free energy by a constant that is related to the size of network. In this study, we propose that RBM function approximation can be further improved by approximating the value function by the negative expected energy (EERL), instead of the negative free energy, as well as being able to handle continuous state input. We validate our proposed method by demonstrating that EERL: (1) outperforms FERL, as well as standard neural network and linear function approximation, for three versions of a gridworld task with high-dimensional image state input; (2) achieves new state-of-the-art results in stochastic SZ-Tetris in both model-free and model-based learning settings; and (3) significantly outperforms FERL and standard neural network function approximation for a robot navigation task with raw and noisy RGB images as state input and a large number of actions. Copyright © 2016 The Author(s). Published by Elsevier Ltd.. All rights reserved.
New angles on energy correlation functions
Moult, Ian; Necib, Lina; Thaler, Jesse
2016-12-01
Jet substructure observables, designed to identify specific features within jets, play an essential role at the Large Hadron Collider (LHC), both for searching for signals beyond the Standard Model and for testing QCD in extreme phase space regions. In this paper, we systematically study the structure of infrared and collinear safe substructure observables, defining a generalization of the energy correlation functions to probe n-particle correlations within a jet. These generalized correlators provide a flexible basis for constructing new substructure observables optimized for specific purposes. Focusing on three major targets of the jet substructure community — boosted top tagging, boosted W/Z/H tagging, and quark/gluon discrimination — we use power-counting techniques to identify three new series of powerful discriminants: M i , N i , and U i . The M i series is designed for use on groomed jets, providing a novel example of observables with improved discrimination power after the removal of soft radiation. The N i series behave parametrically like the N -subjettiness ratio observables, but are defined without respect to subjet axes, exhibiting improved behavior in the unresolved limit. Finally, the U i series improves quark/gluon discrimination by using higher-point correlators to simultaneously probe multiple emissions within a jet. Taken together, these observables broaden the scope for jet substructure studies at the LHC.
New angles on energy correlation functions
Energy Technology Data Exchange (ETDEWEB)
Moult, Ian [Berkeley Center for Theoretical Physics, University of California,Berkeley, CA 94720 (United States); Theoretical Physics Group, Lawrence Berkeley National Laboratory,Berkeley, CA 94720 (United States); Center for Theoretical Physics, Massachusetts Institute of Technology,Cambridge, MA 02139 (United States); Necib, Lina; Thaler, Jesse [Center for Theoretical Physics, Massachusetts Institute of Technology,Cambridge, MA 02139 (United States)
2016-12-29
Jet substructure observables, designed to identify specific features within jets, play an essential role at the Large Hadron Collider (LHC), both for searching for signals beyond the Standard Model and for testing QCD in extreme phase space regions. In this paper, we systematically study the structure of infrared and collinear safe substructure observables, defining a generalization of the energy correlation functions to probe n-particle correlations within a jet. These generalized correlators provide a flexible basis for constructing new substructure observables optimized for specific purposes. Focusing on three major targets of the jet substructure community — boosted top tagging, boosted W/Z/H tagging, and quark/gluon discrimination — we use power-counting techniques to identify three new series of powerful discriminants: M{sub i}, N{sub i}, and U{sub i}. The M{sub i} series is designed for use on groomed jets, providing a novel example of observables with improved discrimination power after the removal of soft radiation. The N{sub i} series behave parametrically like the N-subjettiness ratio observables, but are defined without respect to subjet axes, exhibiting improved behavior in the unresolved limit. Finally, the U{sub i} series improves quark/gluon discrimination by using higher-point correlators to simultaneously probe multiple emissions within a jet. Taken together, these observables broaden the scope for jet substructure studies at the LHC.
Energy density functional analysis of shape coexistence in 44S
International Nuclear Information System (INIS)
Li, Z. P.; Yao, J. M.; Vretenar, D.; Nikšić, T.; Meng, J.
2012-01-01
The structure of low-energy collective states in the neutron-rich nucleus 44 S is analyzed using a microscopic collective Hamiltonian model based on energy density functionals (EDFs). The calculated triaxial energy map, low-energy spectrum and corresponding probability distributions indicate a coexistence of prolate and oblate shapes in this nucleus.
A Cellular Perspective on Brain Energy Metabolism and Functional Imaging
Magistretti, Pierre J.; Allaman, Igor
2015-01-01
The energy demands of the brain are high: they account for at least 20% of the body's energy consumption. Evolutionary studies indicate that the emergence of higher cognitive functions in humans is associated with an increased glucose utilization
Enhancement of biodiversity in energy farming: towards a functional approach
International Nuclear Information System (INIS)
Londo, M.; Dekker, J.
1997-01-01
When biomass is a substantial sustainable energy source, and special energy crops are grown on a large scale, land use and the environment of agriculture will be affected. Of these effects, biodiversity deserves special attention. The enhancement of biodiversity in energy farming via standard setting is the overall purpose of this project. In this study, the potential functionality of biodiversity in energy farming is proposed as a way of operationalising the rather abstract and broad concept of biodiversity. Functions of biodiversity are reviewed, and examples of functions are worked out, based on the current literature of nature in energy farming systems. (author)
Functionally graded biomimetic energy absorption concept development for transportation systems.
2014-02-01
Mechanics of a functionally graded cylinder subject to static or dynamic axial loading is considered, including a potential application as energy absorber. The mass density and stiffness are power functions of the radial coordinate as may be the case...
Kramers-Kronig transform for the surface energy loss function
International Nuclear Information System (INIS)
Tan, G.L.; DeNoyer, L.K.; French, R.H.; Guittet, M.J.; Gautier-Soyer, M.
2005-01-01
A new pair of Kramers-Kronig (KK) dispersion relationships for the transformation of surface energy loss function Im[-1/(ε + 1)] has been proposed. The validity of the new surface KK transform is confirmed, using both a Lorentz oscillator model and the surface energy loss functions determined from the experimental complex dielectric function of SrTiO 3 and tungsten metal. The interband transition strength spectra (J cv ) have been derived either directly from the original complex dielectric function or from the derived dielectric function obtained from the KK transform of the surface energy loss function. The original J cv trace and post-J cv trace overlapped together for the three modes, indicating that the new surface Kramers-Kronig dispersion relationship is valid for the surface energy loss function
Liver Function Status in some Nigerian Children with Protein Energy ...
African Journals Online (AJOL)
Objective: To ascertain functional status of the liver in Nigeria Children with Protein energy malnutrition. Materials and Methods: Liver function tests were performed on a total of 88 children with protein energy malnutrition (PEM). These were compared with 22 apparently well-nourished children who served as controls.
Energy expressions in density-functional theory using line integrals.
van Leeuwen, R.; Baerends, E.J.
1995-01-01
In this paper we will address the question of how to obtain energies from functionals when only the functional derivative is given. It is shown that one can obtain explicit expressions for the exchange-correlation energy from approximate exchange-correlation potentials using line integrals along
Analytical potential energy function for the Br + H2 system
International Nuclear Information System (INIS)
Kurosaki, Yuzuru
2001-01-01
Analytical functions with a many-body expansion for the ground and first-excited-state potential energy surfaces for the Br+H 2 system are newly presented in this work. These functions describe the abstraction and exchange reactions qualitatively well, although it has been found that the function for the ground-state potential surface is still quantitatively unsatisfactory. (author)
Structure and potential energy function for Pu22+ ion
International Nuclear Information System (INIS)
Li Quan; Huang Hui; Li Daohua
2003-01-01
The theoretical study on Pu 2 2+ using density functional method shows that the molecular ion is metastable. Ground electronic state is 13 Σ g for Pu 2 2+ , the analytic potential energy function is in well agreement with the Z-W function, and the force constants and spectroscopic data have been worked out for the first time
Green close-quote s function method with energy-independent vertex functions
International Nuclear Information System (INIS)
Tsay Tzeng, S.Y.; Kuo, T.T.; Tzeng, Y.; Geyer, H.B.; Navratil, P.
1996-01-01
In conventional Green close-quote s function methods the vertex function Γ is generally energy dependent. However, a model-space Green close-quote s function method where the vertex function is manifestly energy independent can be formulated using energy-independent effective interaction theories based on folded diagrams and/or similarity transformations. This is discussed in general and then illustrated for a 1p1h model-space Green close-quote s function applied to a solvable Lipkin many-fermion model. The poles of the conventional Green close-quote s function are obtained by solving a self-consistent Dyson equation and model space calculations may lead to unphysical poles. For the energy-independent model-space Green close-quote s function only the physical poles of the model problem are reproduced and are in satisfactory agreement with the exact excitation energies. copyright 1996 The American Physical Society
Measuring structure functions at SSC energies
International Nuclear Information System (INIS)
Morfin, J.G.; Owens, J.F.
1985-01-01
Topics discussed include measuring Λ, tests of QCD using hard scattering processes, and measuring parton distributions. In each case, any opportunities and advantages afforded by the unique features of the SSC are emphasized. The working group on structure functions was charged with investigating two specific questions: (1) How well are the various parton distributions known in the kinematic region relevant to calculations for the SSC. (2) What new information can be learned about parton distributions at the SSC. Especially for this working group, the advantages of having a fixed-target facility at the SSC for the measurement of the parton distributions with multi-TeV leptons, were to be examined. 15 references
Zeta-function approach to Casimir energy with singular potentials
International Nuclear Information System (INIS)
Khusnutdinov, Nail R.
2006-01-01
In the framework of zeta-function approach the Casimir energy for three simple model system: single delta potential, step function potential and three delta potentials are analyzed. It is shown that the energy contains contributions which are peculiar to the potentials. It is suggested to renormalize the energy using the condition that the energy of infinitely separated potentials is zero which corresponds to subtraction all terms of asymptotic expansion of zeta-function. The energy obtained in this way obeys all physically reasonable conditions. It is finite in the Dirichlet limit, and it may be attractive or repulsive depending on the strength of potential. The effective action is calculated, and it is shown that the surface contribution appears. The renormalization of the effective action is discussed
A Cellular Perspective on Brain Energy Metabolism and Functional Imaging
Magistretti, Pierre J.
2015-05-01
The energy demands of the brain are high: they account for at least 20% of the body\\'s energy consumption. Evolutionary studies indicate that the emergence of higher cognitive functions in humans is associated with an increased glucose utilization and expression of energy metabolism genes. Functional brain imaging techniques such as fMRI and PET, which are widely used in human neuroscience studies, detect signals that monitor energy delivery and use in register with neuronal activity. Recent technological advances in metabolic studies with cellular resolution have afforded decisive insights into the understanding of the cellular and molecular bases of the coupling between neuronal activity and energy metabolism and pointat a key role of neuron-astrocyte metabolic interactions. This article reviews some of the most salient features emerging from recent studies and aims at providing an integration of brain energy metabolism across resolution scales. © 2015 Elsevier Inc.
An enviro-economic function for assessing energy resources for district energy systems
International Nuclear Information System (INIS)
Rezaie, Behnaz; Reddy, Bale V.; Rosen, Marc A.
2014-01-01
District energy (DE) systems provide an important means of mitigating greenhouse gas emissions and the significant related concerns associated with global climate change. DE systems can use fossil fuels, renewable energy and waste heat as energy sources, and facilitate intelligent integration of energy systems. In this study, an enviro-economic function is developed for assessing various energy sources for a district energy system. The DE system is assessed for the considered energy resources by considering two main factors: CO 2 emissions and economics. Using renewable energy resources and associated technologies as the energy suppliers for a DE system yields environmental benefits which can lead to financial advantages through such instruments as tax breaks; while fossil fuels are increasingly penalized by a carbon tax. Considering these factors as well as the financial value of the technology, an analysis approach is developed for energy suppliers of the DE system. In addition, the proposed approach is modified for the case when thermal energy storage is integrated into a DE system. - Highlights: • Developed a function to assess various energy sources for a district energy system. • Considered CO 2 emissions and economics as two main factors. • Applied renewable energy resources technologies as the suppliers for a DE system. • Yields environmental benefits can lead to financial benefits by tax breaks. • Modified enviro-economic function for the TES integrated into a DE system
Kinetic-energy density functional: Atoms and shell structure
International Nuclear Information System (INIS)
Garcia-Gonzalez, P.; Alvarellos, J.E.; Chacon, E.
1996-01-01
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
Surface energy and work function of elemental metals
DEFF Research Database (Denmark)
Skriver, Hans Lomholt; Rosengaard, N. M.
1992-01-01
and noble metals, as derived from the surface tension of liquid metals. In addition, they give work functions which agree with the limited experimental data obtained from single crystals to within 15%, and explain the smooth behavior of the experimental work functions of polycrystalline samples......We have performed an ab initio study of the surface energy and the work function for six close-packed surfaces of 40 elemental metals by means of a Green’s-function technique, based on the linear-muffin-tin-orbitals method within the tight-binding and atomic-sphere approximations. The results...... are in excellent agreement with a recent full-potential, all-electron, slab-supercell calculation of surface energies and work functions for the 4d metals. The present calculations explain the trend exhibited by the surface energies of the alkali, alkaline earth, divalent rare-earth, 3d, 4d, and 5d transition...
International Nuclear Information System (INIS)
Garcia-Aldea, David; Alvarellos, J. E.
2008-01-01
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
Dependence of the giant dipole strength function on excitation energy
International Nuclear Information System (INIS)
Draper, J.E.; Newton, J.O.; Sobotka, L.G.; Lindenberger, H.; Wozniak, G.J.; Moretto, L.G.; Stephens, F.S.; Diamond, R.M.; McDonald, R.J.
1982-01-01
Spectra of γ rays associated with deep-inelastic products from the 1150-MeV 136 Xe+ 181 Ta reaction have been measured. The yield of 10--20-MeV γ rays initially increases rapidly with the excitation energy of the products and then more slowly for excitation energies in excess of 120 MeV. Statistical-model calculations with ground-state values of the giant dipole strength function fail to reproduce the shape of the measured γ-ray spectra. This suggests a dependence of the giant dipole strength function on excitation energy
Construction of energy loss function for low-energy electrons in helium
Energy Technology Data Exchange (ETDEWEB)
Dayashankar, [Bhabha Atomic Research Centre, Bombay (India). Div. of Radiation Protection
1976-02-01
The energy loss function for electrons in the energy range from 50 eV to 1 keV in helium gas has been constructed by considering separately the energy loss in overcoming the ionization threshold, the loss manifested as kinetic energy of secondary electrons and the loss in the discrete state excitations. This has been done by utilizing recent measurements of Opal et al. on the energy spectrum of secondary electrons and incorporating the experimental data on cross sections for twenty-four excited states. The present results of the energy loss function are in good agreement with the Bethe formula for energies above 500 eV. For lower energies, where the Bethe formula is not applicable, the present results should be particularly useful.
On the low-energy behavior of the Adler function
International Nuclear Information System (INIS)
Nesterenko, A.V.
2009-01-01
The infrared behavior of the Adler function is examined by making use of a recently derived integral representation for the latter. The obtained result for the Adler function agrees with its experimental prediction in the entire energy range. The inclusive τ lepton decay is studied in the framework of the developed approach
On approximation and energy estimates for delta 6-convex functions.
Saleem, Muhammad Shoaib; Pečarić, Josip; Rehman, Nasir; Khan, Muhammad Wahab; Zahoor, Muhammad Sajid
2018-01-01
The smooth approximation and weighted energy estimates for delta 6-convex functions are derived in this research. Moreover, we conclude that if 6-convex functions are closed in uniform norm, then their third derivatives are closed in weighted [Formula: see text]-norm.
On approximation and energy estimates for delta 6-convex functions
Directory of Open Access Journals (Sweden)
Muhammad Shoaib Saleem
2018-02-01
Full Text Available Abstract The smooth approximation and weighted energy estimates for delta 6-convex functions are derived in this research. Moreover, we conclude that if 6-convex functions are closed in uniform norm, then their third derivatives are closed in weighted L2 $L^{2}$-norm.
COULN, a program for evaluating negative energy Coulomb functions
International Nuclear Information System (INIS)
Noble, C.J.; Thompson, I.J.
1984-01-01
Program COULN calculates exponentially decaying Whittaker functions, Wsub(K,μ)(z) corresponding to negative energy Coulomb functions. The method employed is most appropriate for parameter ranges which commonly occur in atomic and molecular asymptotic scattering problems using a close-coupling approximation in the presence of closed channels. (orig.)
Free energy distribution function of a random Ising ferromagnet
International Nuclear Information System (INIS)
Dotsenko, Victor; Klumov, Boris
2012-01-01
We study the free energy distribution function of a weakly disordered Ising ferromagnet in terms of the D-dimensional random temperature Ginzburg–Landau Hamiltonian. It is shown that besides the usual Gaussian 'body' this distribution function exhibits non-Gaussian tails both in the paramagnetic and in the ferromagnetic phases. Explicit asymptotic expressions for these tails are derived. It is demonstrated that the tails are strongly asymmetric: the left tail (for large negative values of the free energy) is much slower than the right one (for large positive values of the free energy). It is argued that at the critical point the free energy of the random Ising ferromagnet in dimensions D < 4 is described by a non-trivial universal distribution function which is non-self-averaging
Upper-bound nature of the Brueckner energy of nuclear matter
International Nuclear Information System (INIS)
Harada, M.
1993-01-01
A trial wavefunction is constructed for nuclear matter in terms of the reaction matrix. The trial function includes only two-particle excitations and the resulting energy expectation value for two-nucleon forces with a state-independent repulsive core of Yukawa shape approaches in the thermodynamic limit the energy given by the lowest order Brueckner theory with standard dispersion. Evaluation of the energy expectation value is carried out in a systematic way by use of an identity that holds between the Hamiltonians and reaction matrix. (Author)
Inferring Parametric Energy Consumption Functions at Different Software Levels
DEFF Research Database (Denmark)
Liqat, Umer; Georgiou, Kyriakos; Kerrison, Steve
2016-01-01
The static estimation of the energy consumed by program executions is an important challenge, which has applications in program optimization and verification, and is instrumental in energy-aware software development. Our objective is to estimate such energy consumption in the form of functions...... on the input data sizes of programs. We have developed a tool for experimentation with static analysis which infers such energy functions at two levels, the instruction set architecture (ISA) and the intermediate code (LLVM IR) levels, and reflects it upwards to the higher source code level. This required...... the development of a translation from LLVM IR to an intermediate representation and its integration with existing components, a translation from ISA to the same representation, a resource analyzer, an ISA-level energy model, and a mapping from this model to LLVM IR. The approach has been applied to programs...
Functionalization of graphene for efficient energy conversion and storage.
Dai, Liming
2013-01-15
As global energy consumption accelerates at an alarming rate, the development of clean and renewable energy conversion and storage systems has become more important than ever. Although the efficiency of energy conversion and storage devices depends on a variety of factors, their overall performance strongly relies on the structure and properties of the component materials. Nanotechnology has opened up new frontiers in materials science and engineering to meet this challenge by creating new materials, particularly carbon nanomaterials, for efficient energy conversion and storage. As a building block for carbon materials of all other dimensionalities (such as 0D buckyball, 1D nanotube, 3D graphite), the two-dimensional (2D) single atomic carbon sheet of graphene has emerged as an attractive candidate for energy applications due to its unique structure and properties. Like other materials, however, a graphene-based material that possesses desirable bulk properties rarely features the surface characteristics required for certain specific applications. Therefore, surface functionalization is essential, and researchers have devised various covalent and noncovalent chemistries for making graphene materials with the bulk and surface properties needed for efficient energy conversion and storage. In this Account, I summarize some of our new ideas and strategies for the controlled functionalization of graphene for the development of efficient energy conversion and storage devices, such as solar cells, fuel cells, supercapacitors, and batteries. The dangling bonds at the edge of graphene can be used for the covalent attachment of various chemical moieties while the graphene basal plane can be modified via either covalent or noncovalent functionalization. The asymmetric functionalization of the two opposite surfaces of individual graphene sheets with different moieties can lead to the self-assembly of graphene sheets into hierarchically structured materials. Judicious
Evaluation of NEB energy markets and supply monitoring function
International Nuclear Information System (INIS)
2003-09-01
Canada's National Energy Board regulates the exports of oil, natural gas, natural gas liquids and electricity. It also regulates the construction, operation and tolls of international and interprovincial pipelines and power lines. It also monitors energy supply and market developments in Canada. The Board commissioned an evaluation of the monitoring function to ensure the effectiveness and efficiency of the monitoring activities, to identify gaps in these activities and to propose recommendations. The objectives of the monitoring mandate are to provide Canadians with information regarding Canadian energy markets, energy supply and demand, and to ensure that exports of natural gas, oil, natural gas liquids and electricity do not occur at the detriment of Canadian energy users. The Board ensures that Canadians have access to domestically produced energy on terms that are as favourable as those available to export buyers. The following recommendations were proposed to improve the monitoring of energy markets and supply: (1) increase focus and analysis on the functioning of gas (first priority) and other commodity markets, (2) increase emphasis on forward-looking market analysis and issue identification, (3) demonstrate continued leadership by encouraging public dialogue on a wide range of energy market issues, (4) improve communication and increase visibility of the NEB within the stakeholder community, (5) build on knowledge management and organizational learning capabilities, (6) improve communication and sharing of information between the Applications and Commodities Business Units, and (7) enhance organizational effectiveness of the Commodities Business Unit. figs
Energy functionals for medical image segmentation: choices and consequences
McIntosh, Christopher
2011-01-01
Medical imaging continues to permeate the practice of medicine, but automated yet accurate segmentation and labeling of anatomical structures continues to be a major obstacle to computerized medical image analysis. Though there exists numerous approaches for medical image segmentation, one in particular has gained increasing popularity: energy minimization-based techniques, and the large set of methods encompassed therein. With these techniques an energy function must be chosen, segmentations...
Energy absorption behaviors of nanoporous materials functionalized (NMF) liquids
Kim, Tae Wan
2011-01-01
For many decades, people have been actively investigating high-performance energy absorption materials, so as to develop lightweight and small-sized protective and damping devices, such as blast mitigation helmets, vehicle armors, etc. Recently, the high energy absorption efficiency of nanoporous materials functionalized (NMF) liquids has drawn considerable attention. A NMF liquid is usually a liquid suspension of nanoporous particles with large nanopore surface areas (100 - 2,000 m²/g). The ...
Range and energy functions of interest in neutron dosimetry
International Nuclear Information System (INIS)
Bhatia, D.P.; Nagarajan, P.S.
1978-01-01
This report documents the energy and range functions generated and used in fast neutron interface dosimetry studies. The basic data of stopping power employed are the most recent. The present report covers a number of media mainly air, oxygen, nitrogen, polythene, graphite, bone and tissue, and a number of charged particles, namely protons, alphas, 9 Be, 11 B, 12 C, 13 C, 14 N and 16 O. These functions would be useful for generation of energy and range values for any of the above particles in any of the above media within +- 1% in any dosimetric calculations. (author)
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...... density, high gradient limit may be subtantially improved by including locally a von Weizsacker term. Based on this, we propose a simple one-parameter Pade's approximation, which reproduces the exact Kohn-Sham surface kinetic energy over the entire range of metallic densities....
Energy Technology Data Exchange (ETDEWEB)
Sillem, E.
2011-06-15
As typical office buildings from the nineties have large heating and cooling installations to provide heat or cold wherever and whenever needed, more recent office buildings have almost no demand for heating due to high internal heat loads caused by people, lighting and office appliances and because of the great thermal qualities of the contemporary building envelope. However, these buildings still have vast cooling units to cool down servers and other energy consuming installations. At the same time other functions such as dwellings, swimming pools, sporting facilities, archives and museums still need to be heated most of the year. In the current building market there is an increasing demand for mixed-use buildings or so called hybrid buildings. The Science Business Centre is no different and houses a conference centre, offices, a museum, archives, an exhibition space and a restaurant. From the initial program brief it seemed that the building will simultaneously house functions that need cooling most of the year and functions that will need to be heated the majority of the year. Can this building be equipped with a 'micro heating and cooling network' and where necessary temporarily store energy? With this idea a research proposal was formulated. How can the demand for heating and cooling of the Science Business Centre be reduced by using energy exchange between different kinds of functions and by temporarily storing energy? In conclusion the research led to: four optimized installation concepts; short term energy storage in pavilion concept and museum; energy exchange between the restaurant and archives; energy exchange between the server space and the offices; the majority of heat and cold will be extracted from the soil (long term energy storage); the access heat will be generated by the energy roof; PV cells from the energy roof power all climate installations; a total energy plan for the Science Business Centre; a systematic approach for exchanging
Energy vs. density on paths toward more exact density functionals.
Kepp, Kasper P
2018-03-14
Recently, the progression toward more exact density functional theory has been questioned, implying a need for more formal ways to systematically measure progress, i.e. a "path". Here I use the Hohenberg-Kohn theorems and the definition of normality by Burke et al. to define a path toward exactness and "straying" from the "path" by separating errors in ρ and E[ρ]. A consistent path toward exactness involves minimizing both errors. Second, a suitably diverse test set of trial densities ρ' can be used to estimate the significance of errors in ρ without knowing the exact densities which are often inaccessible. To illustrate this, the systems previously studied by Medvedev et al., the first ionization energies of atoms with Z = 1 to 10, the ionization energy of water, and the bond dissociation energies of five diatomic molecules were investigated using CCSD(T)/aug-cc-pV5Z as benchmark at chemical accuracy. Four functionals of distinct designs was used: B3LYP, PBE, M06, and S-VWN. For atomic cations regardless of charge and compactness up to Z = 10, the energy effects of the different ρ are energy-wise insignificant. An interesting oscillating behavior in the density sensitivity is observed vs. Z, explained by orbital occupation effects. Finally, it is shown that even large "normal" problems such as the Co-C bond energy of cobalamins can use simpler (e.g. PBE) trial densities to drastically speed up computation by loss of a few kJ mol -1 in accuracy. The proposed method of using a test set of trial densities to estimate the sensitivity and significance of density errors of functionals may be useful for testing and designing new balanced functionals with more systematic improvement of densities and energies.
AN ENERGY FUNCTION APPROACH FOR FINDING ROOTS OF CHARACTERISTIC EQUATION
Deepak Mishra; Prem K. Kalra
2011-01-01
In this paper, an energy function approach for finding roots of a characteristic equation has been proposed. Finding the roots of a characteristics equation is considered as an optimization problem. We demonstrated that this problem can be solved with the application of feedback type neural network. The proposed approach is fast and robust against variation of parameter.
El strength function at high spin and excitation energy
International Nuclear Information System (INIS)
Barrette, J.
1983-04-01
Recently giant dipole resonance-like concentration of the dipole strength function in nuclei was observed at both high excitation energies and high spins. This observation raises the possibility of obtaining new information on the shape of rapidly rotating heated nuclei. Recent experimental results on this subject are reviewed
Ab initio derivation of model energy density functionals
International Nuclear Information System (INIS)
Dobaczewski, Jacek
2016-01-01
I propose a simple and manageable method that allows for deriving coupling constants of model energy density functionals (EDFs) directly from ab initio calculations performed for finite fermion systems. A proof-of-principle application allows for linking properties of finite nuclei, determined by using the nuclear nonlocal Gogny functional, to the coupling constants of the quasilocal Skyrme functional. The method does not rely on properties of infinite fermion systems but on the ab initio calculations in finite systems. It also allows for quantifying merits of different model EDFs in describing the ab initio results. (letter)
On the asymptotic evolution of finite energy Airy wave functions.
Chamorro-Posada, P; Sánchez-Curto, J; Aceves, A B; McDonald, G S
2015-06-15
In general, there is an inverse relation between the degree of localization of a wave function of a certain class and its transform representation dictated by the scaling property of the Fourier transform. We report that in the case of finite energy Airy wave packets a simultaneous increase in their localization in the direct and transform domains can be obtained as the apodization parameter is varied. One consequence of this is that the far-field diffraction rate of a finite energy Airy beam decreases as the beam localization at the launch plane increases. We analyze the asymptotic properties of finite energy Airy wave functions using the stationary phase method. We obtain one dominant contribution to the long-term evolution that admits a Gaussian-like approximation, which displays the expected reduction of its broadening rate as the input localization is increased.
KIDS Nuclear Energy Density Functional: 1st Application in Nuclei
Gil, Hana; Papakonstantinou, Panagiota; Hyun, Chang Ho; Oh, Yongseok
We apply the KIDS (Korea: IBS-Daegu-Sungkyunkwan) nuclear energy density functional model, which is based on the Fermi momentum expansion, to the study of properties of lj-closed nuclei. The parameters of the model are determined by the nuclear properties at the saturation density and theoretical calculations on pure neutron matter. For applying the model to the study of nuclei, we rely on the Skyrme force model, where the Skyrme force parameters are determined through the KIDS energy density functional. Solving Hartree-Fock equations, we obtain the energies per particle and charge radii of closed magic nuclei, namely, 16O, 28O, 40Ca, 48Ca, 60Ca, 90Zr, 132Sn, and 208Pb. The results are compared with the observed data and further improvement of the model is shortly mentioned.
Comment on 'Kinetic energy as a density functional'
International Nuclear Information System (INIS)
Holas, A.; March, N.H.
2002-01-01
In a recent paper, Nesbet [Phys. Rev. A 65, 010502(R) (2001)] has proposed dropping ''the widespread but unjustified assumption that the existence of a ground-state density functional for the kinetic energy, T s [ρ], of an N-electron system implies the existence of a density-functional derivative, δT s [ρ]/δρ(r), equivalent to a local potential function,'' because, according to his arguments, this derivative 'has the mathematical character of a linear operator that acts on orbital wave functions'. Our Comment demonstrates that the statement called by Nesbet an 'unjustified assumption' happens, in fact, to be a rigorously proven theorem. Therefore, his previous conclusions stemming from his different view of this derivative, which undermined the foundations of density-functional theory, can be discounted
Nuclear response functions at large energy and momentum transfer
International Nuclear Information System (INIS)
Bertozzi, W.; Moniz, E.J.; Lourie, R.W.
1991-01-01
Quasifree nucleon processes are expected to dominate the nuclear electromagnetic response function for large energy and momentum transfers, i.e., for energy transfers large compared with nuclear single particle energies and momentum transfers large compared with typical nuclear momenta. Despite the evident success of the quasifree picture in providing the basic frame work for discussing and understanding the large energy, large momentum nuclear response, the limits of this picture have also become quite clear. In this article a selected set of inclusive and coincidence data are presented in order to define the limits of the quasifree picture more quantitatively. Specific dynamical mechanisms thought to be important in going beyond the quasifree picture are discussed as well. 75 refs, 37 figs
Multi functional roof structures of the energy efficient buildings
Directory of Open Access Journals (Sweden)
Krstić Aleksandra
2006-01-01
Full Text Available Modern architectural concepts, which are based on rational energy consumption of buildings and the use of solar energy as a renewable energy source, give the new and significant role to the roofs that become multifunctional structures. Various energy efficient roof structures and elements, beside the role of protection, provide thermal and electric energy supply, natural ventilation and cooling of a building, natural lighting of the indoor space sunbeam protection, water supply for technical use, thus according to the above mentioned functions, classification and analysis of such roof structures and elements are made in this paper. The search for new architectural values and optimization in total energy balance of a building or the likewise for the urban complex, gave to roofs the role of "climatic membranes". Contemporary roof forms and materials clearly exemplify their multifunctional features. There are numerous possibilities to achieve the new and attractive roof design which broadens to the whole construction. With such inducement, this paper principally analyze the configuration characteristics of the energy efficient roof structures and elements, as well as the visual effects that may be achieved by their application.
Free energy functionals for polarization fluctuations: Pekar factor revisited.
Dinpajooh, Mohammadhasan; Newton, Marshall D; Matyushov, Dmitry V
2017-02-14
The separation of slow nuclear and fast electronic polarization in problems related to electron mobility in polarizable media was considered by Pekar 70 years ago. Within dielectric continuum models, this separation leads to the Pekar factor in the free energy of solvation by the nuclear degrees of freedom. The main qualitative prediction of Pekar's perspective is a significant, by about a factor of two, drop of the nuclear solvation free energy compared to the total (electronic plus nuclear) free energy of solvation. The Pekar factor enters the solvent reorganization energy of electron transfer reactions and is a significant mechanistic parameter accounting for the solvent effect on electron transfer. Here, we study the separation of the fast and slow polarization modes in polar molecular liquids (polarizable dipolar liquids and polarizable water force fields) without relying on the continuum approximation. We derive the nonlocal free energy functional and use atomistic numerical simulations to obtain nonlocal, reciprocal space electronic and nuclear susceptibilities. A consistent transition to the continuum limit is introduced by extrapolating the results of finite-size numerical simulation to zero wavevector. The continuum nuclear susceptibility extracted from the simulations is numerically close to the Pekar factor. However, we derive a new functionality involving the static and high-frequency dielectric constants. The main distinction of our approach from the traditional theories is found in the solvation free energy due to the nuclear polarization: the anticipated significant drop of its magnitude with increasing liquid polarizability does not occur. The reorganization energy of electron transfer is either nearly constant with increasing the solvent polarizability and the corresponding high-frequency dielectric constant (polarizable dipolar liquids) or actually noticeably increases (polarizable force fields of water).
Free energy functionals for polarization fluctuations: Pekar factor revisited
International Nuclear Information System (INIS)
Dinpajooh, Mohammadhasan; Newton, Marshall D.; Matyushov, Dmitry V.
2017-01-01
The separation of slow nuclear and fast electronic polarization in problems related to electron mobility in polarizable media was considered by Pekar 70 years ago. This separation leads to the Pekar factor in the free energy of solvation by the nuclear degrees of freedom, within dielectric continuum models. The main qualitative prediction of Pekar’s perspective is a significant, by about a factor of two, drop of the nuclear solvation free energy compared to the total (electronic plus nuclear) free energy of solvation. The Pekar factor enters the solvent reorganization energy of electron transfer reactions and is a significant mechanistic parameter accounting for the solvent effect on electron transfer. We study the separation of the fast and slow polarization modes in polar molecular liquids (polarizable dipolar liquids and polarizable water force fields) without relying on the continuum approximation. We derive the nonlocal free energy functional and use atomistic numerical simulations to obtain nonlocal, reciprocal space electronic and nuclear susceptibilities. A consistent transition to the continuum limit is introduced by extrapolating the results of finite-size numerical simulation to zero wavevector. The continuum nuclear susceptibility extracted from the simulations is numerically close to the Pekar factor. But, we derive a new functionality involving the static and high-frequency dielectric constants. The main distinction of our approach from the traditional theories is found in the solvation free energy due to the nuclear polarization: the anticipated significant drop of its magnitude with increasing liquid polarizability does not occur. The reorganization energy of electron transfer is either nearly constant with increasing the solvent polarizability and the corresponding high-frequency dielectric constant (polarizable dipolar liquids) or actually noticeably increases (polarizable force fields of water).
Hydrophilic functionalized silicon nanoparticles produced by high energy ball milling
Hallmann, Steffen
The mechanochemical synthesis of functionalized silicon nanoparticles using High Energy Ball Milling (HEBM) is described. This method facilitates the fragmentation of mono crystalline silicon into the nanometer regime and the simultaneous surface functionalization of the formed particles. The surface functionalization is induced by the reaction of an organic liquid, such as alkynes and alkenes with reactive silicon sites. This method can be applied to form water soluble silicon nanoparticles by lipid mediated micelle formation and the milling in organic liquids containing molecules with bi-functional groups, such as allyl alcohol. Furthermore, nanometer sized, chloroalkyl functionalized particles can be synthesized by milling the silicon precursor in the presence of an o-chloroalkyne with either alkenes or alkynes as coreactants. This process allows tuning of the concentration of the exposed, alkyl linked chloro groups, simply by varying the relative amounts of the coreactant. The silicon nanoparticles that are formed serve as the starting point for a wide variety of chemical reactions, which may be used to alter the surface properties of the functionalized nanoparticles. Finally, the use of functionalized silicon particles for the production of superhydrophobic films is described. Here HEBM proves to be an efficient method to produce functionalized silicon particles, which can be deposited to form a stable coating exhibiting superhydrophobic properties. The hydrophobicity of the silicon film can be tuned by the milling time and thus the resulting surface roughness of the films.
Many-body theory and Energy Density Functionals
Energy Technology Data Exchange (ETDEWEB)
Baldo, M. [INFN, Catania (Italy)
2016-07-15
In this paper a method is first presented to construct an Energy Density Functional on a microscopic basis. The approach is based on the Kohn-Sham method, where one introduces explicitly the Nuclear Matter Equation of State, which can be obtained by an accurate many-body calculation. In this way it connects the functional to the bare nucleon-nucleon interaction. It is shown that the resulting functional can be performing as the best Gogny force functional. In the second part of the paper it is shown how one can go beyond the mean-field level and the difficulty that can appear. The method is based on the particle-vibration coupling scheme and a formalism is presented that can handle the correct use of the vibrational degrees of freedom within a microscopic approach. (orig.)
The coupled-channel T-matrix: its lowest-order Born + Lanczos approximants
International Nuclear Information System (INIS)
Znojil, M.
1995-01-01
Three iterative methods of solution of the Lippmann-Schwinger equations (viz., the method of continued fractions by J.Horacek and T.Sasakawa), its Born-remainder modification and a coupled-channel matrix-continued-fraction generalization are all interpreted as special cases of a common iterative matrix prescription. Firstly, in terms of certain asymmetric projectors P≠P + , we re-derive the three particular older methods as different realizations of the well-known Lanczos inversion. Then, a generalized iteration method is proposed as a Born-like re-arrangement of any intermediate Lanczos iteration step. A maximal flexibility is achieved in the formalism which might compete with the standard Pade re-summations in practice. Its first few truncations are listed, therefore. 26 refs., 1 tab
Rossen, E.T.R.; Flipse, C.F.J.; Cerda, J.I.
2013-01-01
We have developed an efficient and accurate formalism which allows the simulation at the ab initio level of inelastic electron tunneling spectroscopy data under a scanning tunneling microscope setup. It exploits fully the tunneling regime by carrying out the structural optimization and vibrational
A numerical study of lowest-order short-crested water wave instabilities
DEFF Research Database (Denmark)
Fuhrman, David R.; Madsen, Per A.
2005-01-01
This work presents the first numerical simulations of the long-term evolution of doubly-periodic short-crested wave instabilities, which are the simplest cases involving the three-dimensional instability of genuinely three-dimensional progressive water waves. The simulated evolutions reveal quali...
Efficient modified Jacobi relaxation for minimizing the energy functional
International Nuclear Information System (INIS)
Park, C.H.; Lee, I.; Chang, K.J.
1993-01-01
We present an efficient scheme of diagonalizing large Hamiltonian matrices in a self-consistent manner. In the framework of the preconditioned conjugate gradient minimization of the energy functional, we replace the modified Jacobi relaxation for preconditioning and use for band-by-band minimization the restricted-block Davidson algorithm, in which only the previous wave functions and the relaxation vectors are included additionally for subspace diagonalization. Our scheme is found to be comparable with the preconditioned conjugate gradient method for both large ordered and disordered Si systems, while it is more rapidly converged for systems with transition-metal elements
Trivial constraints on orbital-free kinetic energy density functionals
Luo, Kai; Trickey, S. B.
2018-03-01
Approximate kinetic energy density functionals (KEDFs) are central to orbital-free density functional theory. Limitations on the spatial derivative dependencies of KEDFs have been claimed from differential virial theorems. We identify a central defect in the argument: the relationships are not true for an arbitrary density but hold only for the minimizing density and corresponding chemical potential. Contrary to the claims therefore, the relationships are not constraints and provide no independent information about the spatial derivative dependencies of approximate KEDFs. A simple argument also shows that validity for arbitrary v-representable densities is not restored by appeal to the density-potential bijection.
The electron energy distribution function of noble gases with flow
International Nuclear Information System (INIS)
Karditsas, P.J.
1989-01-01
The treatment of the Boltzmann equation by several investigators, for the determination of the electron energy distribution function (EEDF) in noble gases was restricted to static discharges. It is of great interest to magnetoplasmadynamic power generation to develop the Boltzmann equation to account for the effect of the bulk fluid flow on the EEDF. The two term expansion of the Boltzmann equation, as given, results in additional terms introduced to the equations due to the bulk fluid flow, with velocity u
Energy Technology Data Exchange (ETDEWEB)
Shamim, Md; Harbola, Manoj K, E-mail: sami@iitk.ac.i, E-mail: mkh@iitk.ac.i [Department of Physics, Indian Institute of Technology, Kanpur 208 016 (India)
2010-11-14
Transition energies of a new class of excited states (two-gap systems) of various atoms are calculated in time-independent density functional formalism by using a recently proposed local density approximation exchange energy functional for excited states. It is shown that the excitation energies calculated with this functional compare well with those calculated with exact exchange theories.
International Nuclear Information System (INIS)
Shamim, Md; Harbola, Manoj K
2010-01-01
Transition energies of a new class of excited states (two-gap systems) of various atoms are calculated in time-independent density functional formalism by using a recently proposed local density approximation exchange energy functional for excited states. It is shown that the excitation energies calculated with this functional compare well with those calculated with exact exchange theories.
A new empirical potential energy function for Ar2
Myatt, Philip T.; Dham, Ashok K.; Chandrasekhar, Pragna; McCourt, Frederick R. W.; Le Roy, Robert J.
2018-06-01
A critical re-analysis of all available spectroscopic and virial coefficient data for Ar2 has been used to determine an improved empirical analytic potential energy function that has been 'tuned' to optimise its agreement with viscosity, diffusion and thermal diffusion data, and whose short-range behaviour is in reasonably good agreement with the most recent ab initio calculations for this system. The recommended Morse/long-range potential function is smooth and differentiable at all distances, and incorporates both the correct theoretically predicted long-range behaviour and the correct limiting short-range functional behaviour. The resulting value of the well depth is ? cm-1 and the associated equilibrium distance is re = 3.766 (±0.002) Å, while the 40Ar s-wave scattering length is -714 Å.
Energy demand with the flexible double-logarithmic functional form
International Nuclear Information System (INIS)
Nan, G.D.; Murry, D.A.
1992-01-01
A flexible double-logarithmic function form is developed to meet assumptions of consumer behavior. Then annual residential and commercial data (1970-87) are applied to this functional form to examine demand for petroleum products, electricity, and natural gas in California. The traditional double log-linear functional form has shortcomings of constant elasticities. The regression equations in this study, with varied estimated elasticities, overcome some of these shortcomings. All short-run own-price elasticities are inelastic and all income elasticities are close to unity in this study. According to the short-run time-trend elasticities, consumers' fuel preference in California is electricity. The long-run income elasticities also indicate that the residential consumers will consume more electricity and natural gas as their energy budgets increase in the long run. 14 refs., 5 tabs
Horn, Paul R; Head-Gordon, Martin
2016-02-28
In energy decomposition analysis (EDA) of intermolecular interactions calculated via density functional theory, the initial supersystem wavefunction defines the so-called "frozen energy" including contributions such as permanent electrostatics, steric repulsions, and dispersion. This work explores the consequences of the choices that must be made to define the frozen energy. The critical choice is whether the energy should be minimized subject to the constraint of fixed density. Numerical results for Ne2, (H2O)2, BH3-NH3, and ethane dissociation show that there can be a large energy lowering associated with constant density orbital relaxation. By far the most important contribution is constant density inter-fragment relaxation, corresponding to charge transfer (CT). This is unwanted in an EDA that attempts to separate CT effects, but it may be useful in other contexts such as force field development. An algorithm is presented for minimizing single determinant energies at constant density both with and without CT by employing a penalty function that approximately enforces the density constraint.
Impact of energy efficiency gains on output and energy use with Cobb-Douglas production function
International Nuclear Information System (INIS)
Wei Taoyuan
2007-01-01
A special issue of Energy Policy-28 (2000)-was devoted to a collection of papers, edited by Dr. Lee Schipper. The collection included a paper entitled 'A view from the macro side: rebound, backfire, and Khazzoom-Brookes' in which it was argued that the impact of fuel efficiency gains on output (roughly, GDP) is likely to be relatively small by Cobb-Douglas production function. However, an error in the analysis leads to under-estimation of the long-term impact. This paper first provides a partial equilibrium analysis by an alternative method for the same case and then proceeds to an analysis on the issue in a two-sector general equilibrium system. In the latter analysis, energy price is internalized. Both energy use efficiency and energy production efficiency are involved
Consequences of wave function orthogonality for medium energy nuclear reactions
International Nuclear Information System (INIS)
Noble, J.V.
1978-01-01
In the usual models of high-energy bound-state to continuum transitions no account is taken of the orthogonality of the bound and continuum wave functions. This orthogonality induces considerable cancellations in the overlap integrals expressing the transition amplitudes for reactions such as (e,e'p), (γ,p), and (π,N), which are simply not included in the distorted-wave Born-approximation calculations which to date remain the only computationally feasible heirarchy of approximations. The object of this paper is to present a new formulation of the bound-state to continuum transition problem, based upon flux conservation, in which the orthogonality of wave functions is taken into account ab initio. The new formulation, while exact if exact wave functions are used, offers the possibility of using approximate wave functions for the continuum states without doing violence to the cancellations induced by orthogonality. The method is applied to single-particle states obeying the Schroedinger and Dirac equations, as well as to a coupled-channel model in which absorptive processes can be described in a fully consistent manner. Several types of absorption vertex are considered, and in the (π,N) case the equivalence of pseudoscalar and pseudovector πNN coupling is seen to follow directly from wave function orthogonality
Descriptions of carbon isotopes within the energy density functional theory
Energy Technology Data Exchange (ETDEWEB)
Ismail, Atef [Fundamental and Applied Sciences Department, Universiti Teknologi PETRONAS, Bandar Seri Iskandar, 31750 Tronoh, Perak, Malaysia and Department of Physics, Al-Azhar University, 71524 Assiut (Egypt); Cheong, Lee Yen; Yahya, Noorhana [Fundamental and Applied Sciences Department, Universiti Teknologi PETRONAS, Bandar Seri Iskandar, 31750 Tronoh, Perak (Malaysia); Tammam, M. [Department of Physics, Al-Azhar University, 71524 Assiut (Egypt)
2014-10-24
Within the energy density functional (EDF) theory, the structure properties of Carbon isotopes are systematically studied. The shell model calculations are done for both even-A and odd-A nuclei, to study the structure of rich-neutron Carbon isotopes. The EDF theory indicates the single-neutron halo structures in {sup 15}C, {sup 17}C and {sup 19}C, and the two-neutron halo structures in {sup 16}C and {sup 22}C nuclei. It is also found that close to the neutron drip-line, there exist amazing increase in the neutron radii and decrease on the binding energies BE, which are tightly related with the blocking effect and correspondingly the blocking effect plays a significant role in the shell model configurations.
Descriptions of carbon isotopes within the energy density functional theory
International Nuclear Information System (INIS)
Ismail, Atef; Cheong, Lee Yen; Yahya, Noorhana; Tammam, M.
2014-01-01
Within the energy density functional (EDF) theory, the structure properties of Carbon isotopes are systematically studied. The shell model calculations are done for both even-A and odd-A nuclei, to study the structure of rich-neutron Carbon isotopes. The EDF theory indicates the single-neutron halo structures in 15 C, 17 C and 19 C, and the two-neutron halo structures in 16 C and 22 C nuclei. It is also found that close to the neutron drip-line, there exist amazing increase in the neutron radii and decrease on the binding energies BE, which are tightly related with the blocking effect and correspondingly the blocking effect plays a significant role in the shell model configurations
Non-empirical energy density functional for the nuclear structure
International Nuclear Information System (INIS)
Rot ival, V.
2008-09-01
The energy density functional (EDF) formalism is the tool of choice for large-scale low-energy nuclear structure calculations both for stable experimentally known nuclei whose properties are accurately reproduced and systems that are only theoretically predicted. We highlight in the present dissertation the capability of EDF methods to tackle exotic phenomena appearing at the very limits of stability, that is the formation of nuclear halos. We devise a new quantitative and model-independent method that characterizes the existence and properties of halos in medium- to heavy-mass nuclei, and quantifies the impact of pairing correlations and the choice of the energy functional on the formation of such systems. These results are found to be limited by the predictive power of currently-used EDFs that rely on fitting to known experimental data. In the second part of this dissertation, we initiate the construction of non-empirical EDFs that make use of the new paradigm for vacuum nucleon-nucleon interactions set by so-called low-momentum interactions generated through the application of renormalization group techniques. These soft-core vacuum potentials are used as a step-stone of a long-term strategy which connects modern many-body techniques and EDF methods. We provide guidelines for designing several non-empirical models that include in-medium many-body effects at various levels of approximation, and can be handled in state-of-the art nuclear structure codes. In the present work, the first step is initiated through the adjustment of an operator representation of low-momentum vacuum interactions using a custom-designed parallel evolutionary algorithm. The first results highlight the possibility to grasp most of the relevant physics for low-energy nuclear structure using this numerically convenient Gaussian vertex. (author)
Rydberg energies using excited state density functional theory
International Nuclear Information System (INIS)
Cheng, C.-L.; Wu Qin; Van Voorhis, Troy
2008-01-01
We utilize excited state density functional theory (eDFT) to study Rydberg states in atoms. We show both analytically and numerically that semilocal functionals can give quite reasonable Rydberg energies from eDFT, even in cases where time dependent density functional theory (TDDFT) fails catastrophically. We trace these findings to the fact that in eDFT the Kohn-Sham potential for each state is computed using the appropriate excited state density. Unlike the ground state potential, which typically falls off exponentially, the sequence of excited state potentials has a component that falls off polynomially with distance, leading to a Rydberg-type series. We also address the rigorous basis of eDFT for these systems. Perdew and Levy have shown using the constrained search formalism that every stationary density corresponds, in principle, to an exact stationary state of the full many-body Hamiltonian. In the present context, this means that the excited state DFT solutions are rigorous as long as they deliver the minimum noninteracting kinetic energy for the given density. We use optimized effective potential techniques to show that, in some cases, the eDFT Rydberg solutions appear to deliver the minimum kinetic energy because the associated density is not pure state v-representable. We thus find that eDFT plays a complementary role to constrained DFT: The former works only if the excited state density is not the ground state of some potential while the latter applies only when the density is a ground state density.
Energy coupling function and solar wind-magnetosphere dynamo
International Nuclear Information System (INIS)
Kan, J.R.; Lee, L.C.
1979-01-01
The power delivered by the solar wind dynamo to the open magnetosphere is calculated based on the concept of field line reconnection, independent of the MHD steady reconnection theories. By recognizing a previously overlooked geometrical relationship between the reconnection electric field and the magnetic field, the calculated power is shown to be approximately proportional to the Akasofu-Perreault energy coupling function for the magnetospheric substorm. In addition to the polar cap potential, field line reconnection also gives rise to parallel electric fields on open field lines in the high-latitude cusp and the polar cap reions
Relativistic Energy Density Functionals: Exotic modes of excitation
International Nuclear Information System (INIS)
Vretenar, D.; Paar, N.; Marketin, T.
2008-01-01
The framework of relativistic energy density functionals has been applied to the description of a variety of nuclear structure phenomena, not only in spherical and deformed nuclei along the valley of β-stability, but also in exotic systems with extreme isospin values and close to the particle drip-lines. Dynamical aspects of exotic nuclear structure have been investigated with the relativistic quasiparticle random-phase approximation. We present results for the evolution of low-lying dipole (pygmy) strength in neutron-rich nuclei, and charged-current neutrino-nucleus cross sections.
Systematics of strength function sum rules
Directory of Open Access Journals (Sweden)
Calvin W. Johnson
2015-11-01
Full Text Available Sum rules provide useful insights into transition strength functions and are often expressed as expectation values of an operator. In this letter I demonstrate that non-energy-weighted transition sum rules have strong secular dependences on the energy of the initial state. Such non-trivial systematics have consequences: the simplification suggested by the generalized Brink–Axel hypothesis, for example, does not hold for most cases, though it weakly holds in at least some cases for electric dipole transitions. Furthermore, I show the systematics can be understood through spectral distribution theory, calculated via traces of operators and of products of operators. Seen through this lens, violation of the generalized Brink–Axel hypothesis is unsurprising: one expects sum rules to evolve with excitation energy. Furthermore, to lowest order the slope of the secular evolution can be traced to a component of the Hamiltonian being positive (repulsive or negative (attractive.
Strict calculation of electron energy distribution functions in inhomogeneous plasmas
International Nuclear Information System (INIS)
Winkler, R.
1996-01-01
It is objective of the paper to report on strict calculations of the velocity or energy distribution function function and related macroscopic properties of the electrons from appropriate electron kinetic equations under various plasma conditions and to contribute to a better understanding of the electron behaviour in inhomogeneous plasma regions. In particular, the spatial relaxation of plasma electrons acted upon by uniform electric fields, the response of plasma electrons on spatial disturbances of the electric field, the electron kinetics under the impact of space charge field confinement in the dc column plasma and the electron velocity distribution is stronger field as occurring in the electrode regions of a dc glow discharge is considered. (author)
Building a universal nuclear energy density functional (UNEDF)
Energy Technology Data Exchange (ETDEWEB)
Nazarewicz, Witold [Univ. of Tennessee, Knoxville, TN (United States)
2012-07-01
The long-term vision initiated with UNEDF is to arrive at a comprehensive, quantitative, and unified description of nuclei and their reactions, grounded in the fundamental interactions between the constituent nucleons. We seek to replace current phenomenological models of nuclear structure and reactions with a well-founded microscopic theory that delivers maximum predictive power with well-quantified uncertainties. Specifically, the mission of this project has been three-fold: First, to find an optimal energy density functional (EDF) using all our knowledge of the nucleonic Hamiltonian and basic nuclear properties. Second, to apply the EDF theory and its extensions to validate the functional using all the available relevant nuclear structure and reaction data. Third, to apply the validated theory to properties of interest that cannot be measured, in particular the properties needed for reaction theory.
Structures and potential energy functions of Pu3 molecule
International Nuclear Information System (INIS)
Meng Daqiao; Jiang Gang; Liu Xiaoya; Luo Deli; Zhu Zhenghe
2001-01-01
Density functional (B3LYP) method with relativistic effective core potential (RECP) has been used to optimize the structures of Pu 2 and Pu 3 molecules. The results show that the ground states of Pu 2 and Pu 3 molecules are of D ∞h and D 3h symmetry, and of 13 and 19 fold, respectively. The spectral constants of Pu 2 , ω e = 52.3845 cm -1 and ω e x e = 0.0201 cm -1 , and the harmonic frequencies of Pu 3 , ν 1 = 56.9007 cm -1 , ν 2 = 57.1816 cm - '1 and ν 3 = 64.0785 cm -1 , have also been obtained on the B3LYP/RECP level. The potential energy functions of Pu 2 and Pu 3 have been derived, for the first time so far as known, from normal equation fitting and the many-body expansion theory
Energy and enthalpy distribution functions for a few physical systems.
Wu, K L; Wei, J H; Lai, S K; Okabe, Y
2007-08-02
The present work is devoted to extracting the energy or enthalpy distribution function of a physical system from the moments of the distribution using the maximum entropy method. This distribution theory has the salient traits that it utilizes only the experimental thermodynamic data. The calculated distribution functions provide invaluable insight into the state or phase behavior of the physical systems under study. As concrete evidence, we demonstrate the elegance of the distribution theory by studying first a test case of a two-dimensional six-state Potts model for which simulation results are available for comparison, then the biphasic behavior of the binary alloy Na-K whose excess heat capacity, experimentally observed to fall in a narrow temperature range, has yet to be clarified theoretically, and finally, the thermally induced state behavior of a collection of 16 proteins.
Response function measurement of plastic scintillator for high energy neutrons
International Nuclear Information System (INIS)
Sanami, Toshiya; Ban, Syuichi; Takahashi, Kazutoshi; Takada, Masashi
2003-01-01
The response function and detection efficiency of 2''φ x 2''L plastic (PilotU) and NE213 liquid (2''NE213) scintillators, which were used for the measurement of secondary neutrons from high energy electron induced reactions, were measured at Heavy Ion Medical Accelerator in Chiba (HIMAC). High energy neutrons were produced via 400 MeV/n C beam bombardment on a thick graphite target. The detectors were placed at 15 deg with respect to C beam axis, 5 m away from the target. As standard, a 5''φ x 5''L NE213 liquid scintillator (5''NE213) was also placed at same position. Neutron energy was determined by the time-of-flight method with the beam pickup scintillator in front of the target. In front of the detectors, veto scintillators were placed to remove charged particle events. All detector signals were corrected with list mode event by event. We deduce neutron spectrum for each detectors. The efficiency curves for pilotU and 2''NE213 were determined on the bases of 5 N E213 neutron spectrum and its efficiency calculated by CECIL code. (author)
E1 and M1 strength functions at low energy
Schwengner, Ronald; Massarczyk, Ralph; Bemmerer, Daniel; Beyer, Roland; Junghans, Arnd R.; Kögler, Toni; Rusev, Gencho; Tonchev, Anton P.; Tornow, Werner; Wagner, Andreas
2017-09-01
We report photon-scattering experiments using bremsstrahlung at the γELBE facility of Helmholtz-Zentrum Dresden-Rossendorf and using quasi-monoenergetic, polarized γ beams at the HIγS facility of the Triangle Universities Nuclear Laboratory in Durham. To deduce the photoabsorption cross sections at high excitation energy and high level density, unresolved strength in the quasicontinuum of nuclear states has been taken into account. In the analysis of the spectra measured by using bremsstrahlung at γELBE, we perform simulations of statistical γ-ray cascades using the code γDEX to estimate intensities of inelastic transitions to low-lying excited states. Simulated average branching ratios are compared with model-independent branching ratios obtained from spectra measured by using monoenergetic γ beams at HIγS. E1 strength in the energy region of the pygmy dipole resonance is discussed in nuclei around mass 90 and in xenon isotopes. M1 strength in the region of the spin-flip resonance is also considered for xenon isotopes. The dipole strength function of 74Ge deduced from γELBE experiments is compared with the one obtained from experiments at the Oslo Cyclotron Laboratory. The low-energy upbend seen in the Oslo data is interpreted as M1 strength on the basis of shell-model calculations.
E1 and M1 strength functions at low energy
Directory of Open Access Journals (Sweden)
Schwengner Ronald
2017-01-01
Full Text Available We report photon-scattering experiments using bremsstrahlung at the γELBE facility of Helmholtz-Zentrum Dresden-Rossendorf and using quasi-monoenergetic, polarized γ beams at the HIγS facility of the Triangle Universities Nuclear Laboratory in Durham. To deduce the photoabsorption cross sections at high excitation energy and high level density, unresolved strength in the quasicontinuum of nuclear states has been taken into account. In the analysis of the spectra measured by using bremsstrahlung at γELBE, we perform simulations of statistical γ-ray cascades using the code γDEX to estimate intensities of inelastic transitions to low-lying excited states. Simulated average branching ratios are compared with model-independent branching ratios obtained from spectra measured by using monoenergetic γ beams at HIγS. E1 strength in the energy region of the pygmy dipole resonance is discussed in nuclei around mass 90 and in xenon isotopes. M1 strength in the region of the spin-flip resonance is also considered for xenon isotopes. The dipole strength function of 74Ge deduced from γELBE experiments is compared with the one obtained from experiments at the Oslo Cyclotron Laboratory. The low-energy upbend seen in the Oslo data is interpreted as M1 strength on the basis of shell-model calculations.
Harris functional and related methods for calculating total energies in density-functional theory
International Nuclear Information System (INIS)
Averill, F.W.; Painter, G.S.
1990-01-01
The simplified energy functional of Harris has given results of useful accuracy for systems well outside the limits of weakly interacting fragments for which the method was originally proposed. In the present study, we discuss the source of the frequent good agreement of the Harris energy with full Kohn-Sham self-consistent results. A procedure is described for extending the applicability of the scheme to more strongly interacting systems by going beyond the frozen-atom fragment approximation. A gradient-force expression is derived, based on the Harris functional, which accounts for errors in the fragment charge representation. Results are presented for some diatomic molecules, illustrating the points of this study
Building A Universal Nuclear Energy Density Functional (UNEDF)
Energy Technology Data Exchange (ETDEWEB)
Carlson, Joe [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Furnstahl, Dick [The Ohio State Univ., Columbus, OH (United States); Horoi, Mihai [Central Michigan Univ., Mount Pleasant, MI (United States); Lusk, Rusty [Argonne National Lab. (ANL), Argonne, IL (United States); Nazarewicz, Witek [Univ. of Tennessee, Knoxville, TN (United States); Ng, Esmond [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Thompson, Ian [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Vary, James [Iowa State Univ., Ames, IA (United States)
2012-09-30
During the period of Dec. 1 2006 - Jun. 30, 2012, the UNEDF collaboration carried out a comprehensive study of all nuclei, based on the most accurate knowledge of the strong nuclear interaction, the most reliable theoretical approaches, the most advanced algorithms, and extensive computational resources, with a view towards scaling to the petaflop platforms and beyond. The long-term vision initiated with UNEDF is to arrive at a comprehensive, quantitative, and unified description of nuclei and their reactions, grounded in the fundamental interactions between the constituent nucleons. We seek to replace current phenomenological models of nuclear structure and reactions with a well-founded microscopic theory that delivers maximum predictive power with well-quantified uncertainties. Specifically, the mission of this project has been three-fold: first, to find an optimal energy density functional (EDF) using all our knowledge of the nucleonic Hamiltonian and basic nuclear properties; second, to apply the EDF theory and its extensions to validate the functional using all the available relevant nuclear structure and reaction data; third, to apply the validated theory to properties of interest that cannot be measured, in particular the properties needed for reaction theory. The main physics areas of UNEDF, defined at the beginning of the project, were: ab initio structure; ab initio functionals; DFT applications; DFT extensions; reactions.
Electron energy distribution function control in gas discharge plasmas
International Nuclear Information System (INIS)
Godyak, V. A.
2013-01-01
The formation of the electron energy distribution function (EEDF) and electron temperature in low temperature gas discharge plasmas is analyzed in frames of local and non-local electron kinetics. It is shown, that contrary to the local case, typical for plasma in uniform electric field, there is the possibility for EEDF modification, at the condition of non-local electron kinetics in strongly non-uniform electric fields. Such conditions “naturally” occur in some self-organized steady state dc and rf discharge plasmas, and they suggest the variety of artificial methods for EEDF modification. EEDF modification and electron temperature control in non-equilibrium conditions occurring naturally and those stimulated by different kinds of plasma disturbances are illustrated with numerous experiments. The necessary conditions for EEDF modification in gas discharge plasmas are formulated
Theoretical characterization of electron energy distribution function in RF plasmas
International Nuclear Information System (INIS)
Capitelli, M.; Capriati, G.; Dilonardo, M.; Gorse, C.; Longo, S.
1993-01-01
Different methods for the modeling of low-temperature plasmas of both technological and fundamental interest are discussed. The main concept of all these models is the electron energy distribution function (eedf) which is necessary to calculate the rate coefficients for any chemical reaction involving electrons. Results of eedf calculations in homogeneous SF 6 and SiH 4 plasmas are discussed based on solution of the time-dependent Boltzmann equation. The space-dependent eedf in an RF discharge in He is calculated taking into account the sheath oscillations by a Monte Carlo model assuming the plasma heating mechanism and the electric field determined by using a fluid model. The need to take into account the ambipolar diffusion of electrons in RF discharge modeling is stressed. A self-consistent model based on coupling the equations of the fluid model and the chemical kinetics ones is presented. (orig.)
Green's function calculation of the satellite spectrum of neon
International Nuclear Information System (INIS)
Kheifets, A.S.
1995-01-01
The single-hole Green's function with the lowest-order self-energy part has been used to calculate energies and spectroscopic factors of the neon ion ground and excited states which originated from the removal of the 2s and 2p valence electrons. The simplest two-hole-one-electron ion sates were included explicitly to the self-energy. More complex (m+l)-hole-m-electron states were treated implicitly by using the experimental energy of the two holes in the simplest ion states. The results of the calculation are found to be consistent with experimental satellite line positions and intensities obtained from recent photoionization and electron impact ionization measurements. 20 refs., 5 tabs
Studies on functional polymer films utilizing low energy electron beam
International Nuclear Information System (INIS)
Ando, Masayuki
1992-01-01
Also in adhesives and tackifiers, with the expansion of the fields of application, the required characteristics have become high grade and complex. As one of them, the instantaneous hardening of adhesives can be taken up. In the field of lamination works, the low energy type electron beam accelerators having the linear filament of accelerating voltage below 300 kV were developed in 1970s, and the interest in the development of electron beam-handened adhesives has heightend. The authors have carried out research aiming at heightening the functions of the polymer films obtained by electron beam hardening reaction, and developed the adhesives. In this report, the features of electron beam hardening reaction, the structure and properties of electron beam-hardened polymer films and the molecular design of electron beam-hardened monomer oligomers are described. The feature of electron beam hardening reaction is the cross-linking of high degree as the structure of oligomers is maintained. By controlling the structure at the time of electron beam hardening, the heightening of the functions of electron beam-hardened polymer films is feasible. (K.I.)
Snow, M E; Crippen, G M
1991-08-01
The structure of the AMBER potential energy surface of the cyclic tetrapeptide cyclotetrasarcosyl is analyzed as a function of the dimensionality of coordinate space. It is found that the number of local energy minima decreases as the dimensionality of the space increases until some limit at which point equipotential subspaces appear. The applicability of energy embedding methods to finding global energy minima in this type of energy-conformation space is explored. Dimensional oscillation, a computationally fast variant of energy embedding is introduced and found to sample conformation space widely and to do a good job of finding global and near-global energy minima.
Physics as a function of energy and luminosity
International Nuclear Information System (INIS)
Ellis, J.
1984-01-01
In this paper, a new physics in the range of mass up to TeV region is discussed. Most of the discussion concern hadron-hadron (hh) colliders, and also electron-positron colliders are discussed. The cross-sections for new particle production in hh colliders have the general Drell-Yan form, in which the differential luminosity for the collision of partons is included. The formulas with the parton distribution scaled up from present energy using the Altarelli-Parisi equations may be approximately correct within a factor of 2 for the production of particles. Some typical parton-parton luminosity functions for proton-proton and proton-antiproton collisions are presented. From the consideration of luminosity, it can be said that the pp colliders are to be preferred. The case studies of some of the possible new physics discussed by Zakharov, mainly on Higgs bosons and supersymmetric particles, but also a few remarks about technicolor are presented. It seems possible to detect technicolor at a large hh collider. The physics reaches of different possible hh colliders are summarized in tables. In the tables, the observable production of Higgses up to 1 TeV in mass, the observable masses for gluinos (squarks) and the technicolor observability are shown. The cleanliness of electron-positron colliders compared to hadron-hadron colliders is pled, a guess is given as to the appropriate conversion factors between the energy in the electron-positron and hh collisions, the complementarity of electron-positron and hh colliders is urged, and it is argued that a rational mix of world accelerators would include both. (Kato, T.)
Croatian Energy Policy as Function of Regional Development and Employment
International Nuclear Information System (INIS)
Potocnik, V.
2006-01-01
The Republic of Croatia has modest proven fossil fuels (oil and gas) reserves and relatively abundant renewable energy potential (wind, solar, biomass, geothermal, hydro), distributed mainly in less developed regions of Croatia. The Croatian energy system is excessively dependent on expensive oil and natural gas (80% of primary energy), compared to the European Union (61%), and the world average (58%). Approximately 60% of total energy is imported, which considerably contributes to the country's very high foreign trade deficit and foreign debt. Putting into focus of the Croatian energy policy the improvement of energy efficiency and implementation of renewable energies would significantly increase opportunities for mitigating rather wide regional development disparities and high unemployment rates, at the same time reducing energy import, foreign trade deficit and foreign debt, and contributing to energy security as a part of the national security.(author)
Changes in cotton gin energy consumption apportioned by ten functions
The public is concerned about air quality and sustainability. Cotton producers, gin owners and plant managers are concerned about rising energy prices. Both have an interest in cotton gin energy consumption trends. Changes in cotton gins’ energy consumption over the past fifty years, a period of ...
Association between Energy Availability and Menstrual Function in ...
African Journals Online (AJOL)
Energy intake (EI) minus exercise energy expenditure (EEE) normalized to fat free mass (FFM) determined EA. EI was determined through weight of all food and liquid consumed over three consecutive days. EEE was determined after isolating and deducting energy expended in exercise or physical activity above lifestyle ...
Recycling Energy to Restore Impaired Ankle Function during Human Walking
Collins, S.H.; Kuo, A.D.
2010-01-01
Background: Humans normally dissipate significant energy during walking, largely at the transitions between steps. The ankle then acts to restore energy during push-off, which may be the reason that ankle impairment nearly always leads to poorer walking economy. The replacement of lost energy is
Recycling energy to restore impaired ankle function during human walking.
Directory of Open Access Journals (Sweden)
Steven H Collins
Full Text Available BACKGROUND: Humans normally dissipate significant energy during walking, largely at the transitions between steps. The ankle then acts to restore energy during push-off, which may be the reason that ankle impairment nearly always leads to poorer walking economy. The replacement of lost energy is necessary for steady gait, in which mechanical energy is constant on average, external dissipation is negligible, and no net work is performed over a stride. However, dissipation and replacement by muscles might not be necessary if energy were instead captured and reused by an assistive device. METHODOLOGY/PRINCIPAL FINDINGS: We developed a microprocessor-controlled artificial foot that captures some of the energy that is normally dissipated by the leg and "recycles" it as positive ankle work. In tests on subjects walking with an artificially-impaired ankle, a conventional prosthesis reduced ankle push-off work and increased net metabolic energy expenditure by 23% compared to normal walking. Energy recycling restored ankle push-off to normal and reduced the net metabolic energy penalty to 14%. CONCLUSIONS/SIGNIFICANCE: These results suggest that reduced ankle push-off contributes to the increased metabolic energy expenditure accompanying ankle impairments, and demonstrate that energy recycling can be used to reduce such cost.
Symmetry Energy as a Function of Density and Mass
International Nuclear Information System (INIS)
Danielewicz, Pawel; Lee, Jenny
2007-01-01
Energy in nuclear matter is, in practice, completely characterized at different densities and asymmetries, when the density dependencies of symmetry energy and of energy of symmetric matter are specified. The density dependence of the symmetry energy at subnormal densities produces mass dependence of nuclear symmetry coefficient and, thus, can be constrained by that latter dependence. We deduce values of the mass dependent symmetry coefficients, by using excitation energies to isobaric analog states. The coefficient systematic, for intermediate and high masses, is well described in terms of the symmetry coefficient values of a a V = (31.5-33.5) MeV for the volume coefficient and a a S = (9-12) MeV for the surface coefficient. These two further correspond to the parameter values describing density dependence of symmetry energy, of L∼95 MeV and K sym ∼25 MeV
Local functional derivative of the total energy and the shell structure in atoms and molecules
Pino, R.; Markvoort, Albert. J.; Santen, van R.A.; Hilbers, P.A.J.
2003-01-01
The full and local Thomas–Fermi–Dirac energy functional derivatives are evaluated at Hartree–Fock densities for several atoms and molecules. These functions are interpreted as local chemical potentials and related mainly to kinetic energy functional derivatives. They are able to reveal the shell
Boll, Torben; Zhu, Zhiyong; Al-Kassab, Talaat; Schwingenschlö gl, Udo
2012-01-01
In this article the Cu-Au binding energy in Cu3Au is determined by comparing experimental atom probe tomography (APT) results to simulations. The resulting bonding energy is supported by density functional theory calculations. The APT simulations
Functional Modeling of Perspectives on the Example of Electric Energy Systems
DEFF Research Database (Denmark)
Heussen, Kai
2009-01-01
The integration of energy systems is a proven approach to gain higher overall energy efficiency. Invariably, this integration will come with increasing technical complexity through the diversification of energy resources and their functionality. With the integration of more fluctuating renewable ...... which enables a reflection on system integration requirements independent of particular technologies. The results are illustrated on examples related to electric energy systems.......The integration of energy systems is a proven approach to gain higher overall energy efficiency. Invariably, this integration will come with increasing technical complexity through the diversification of energy resources and their functionality. With the integration of more fluctuating renewable...... energies higher system flexibility will also be necessary. One of the challenges ahead is the design of control architecture to enable the flexibility and to handle the diversity. This paper presents an approach to model heterogeneous energy systems and their control on the basis of purpose and functions...
Directory of Open Access Journals (Sweden)
Ion VONCILA
2003-12-01
Full Text Available This paper presents a study of the influence of the main perturbation agent over the functional stability of the triphased asynchronous generator (for the two alternative: with coiled and short circuit rotor, used for the conversion systems from a eolian energy into electric energy.
The energy rebound effects across China’s industrial sectors: An output distance function approach
International Nuclear Information System (INIS)
Li, Ke; Zhang, Ning; Liu, Yanchu
2016-01-01
Highlights: • Output distance function for the energy rebound effect is developed. • The aggregate energy rebound effect of China is 88.42%. • Investment-driven economic growth is not conducive to energy-saving. - Abstract: Improving energy efficiency sustainability is a target of the Chinese government. However, the effectiveness of energy conservation policy is affected by the energy rebound effect under which energy efficiency improvement reduces the effective price of energy services, thereby completely or partially offsetting the energy saved by efficiency improvement. Based on the output distance function, this paper develops an improved estimation model of the energy rebound effect, which is logically consistent with the quantities of energy savings and energy rebounds induced by technological progress. Results show that the aggregate energy rebound effect of 36 industrial sectors in China over 1998–2011 is 88.42%, which implies that most of the expected energy savings are mitigated. Investment-driven economic growth is not conducive to energy-saving and results in a strong energy rebound effect in the following year. The equipment and high-end manufacturing sectors have low levels of rebound effect, indicating that increasing the proportion of such firms in the total manufacturing sector can improve the performance of energy conservation. The high level and heterogeneity in rebound effects strongly suggest that varies strategies are necessary for energy conservation among China’s industrial sectors.
The promotion and control functions of atomic energy law
International Nuclear Information System (INIS)
Roser, T.
1998-01-01
The question about the purpose of atomic energy law may sound superfluous in Germany, a country where a highly differential legal framework for the peaceful utilization of nuclear power has existed for nearly 40 years in the Basic Law, the Atomic Energy Act, and its ordinances, and a comprehensive body of case laws. Yet, it is justified in view of the declared intention of the German federal government to establish an environmental code into which atomic energy law, hitherto an independent branch of the law, would be integrated, and it is justified also in view of persistent complaints that the present rules and regulations stifled investment activities. A look into some codes of law may help answer the question. Already in 1959, the authors of the Atomic Energy Act outlined the purposes of the legislation in relatively clear terms in Section 1. Besides the two foreign policy aspects of security and loyalty under treaties, which do not concern us in this connection, the key purposes of atomic energy law are stated there as promotion and protection. The protection purpose, which implies the need to protect life, health, and property from the hazards of nuclear energy and harmful effects of ionizing radiation, ranks second in the Act. In accordance with the ruling in 1972 of the Federal Administrative Court, however, it should rank at the top. (orig.) [de
International Nuclear Information System (INIS)
Kikuchi, Yasunori; Kimura, Seiichiro; Okamoto, Yoshitaka; Koyama, Michihisa
2014-01-01
Highlights: • Energy flow model was represented as the functionals of technology options. • Relationships among available technologies can be visualized by developed model. • Technology roadmapping can be incorporated into the model as technical scenario. • Combination of technologies can increase their contribution to the environment. - Abstract: The design of energy systems has become an issue all over the world. A single optimal system cannot be suggested because the availability of infrastructure and resources and the acceptability of the system should be discussed locally, involving all related stakeholders in the energy system. In particular, researchers and engineers of technologies related to energy systems should be able to perform the forecasting and roadmapping of future energy systems and indicate quantitative results of scenario analyses. We report an energy flow model developed for analysing scenarios of future Japanese energy systems implementing a variety of feasible technology options. The model was modularized and represented as functionals of appropriate technology options, which enables the aggregation and disaggregation of energy systems by defining functionals for single technologies, packages integrating multi-technologies, and mini-systems such as regions implementing industrial symbiosis. Based on the model, the combinations of technologies on both energy supply and demand sides can be addressed considering not only the societal scenarios such as resource prices, economic growth and population change but also the technical scenarios including the development and penetration of energy-related technologies such as distributed solid oxide fuel cells in residential sectors and new-generation vehicles, and the replacement and shift of current technologies such as heat pumps for air conditioning and centralized power generation. The developed model consists of two main modules; namely, a power generation dispatching module for the
Department of Energy Emergency Management Functional Requirements Study
International Nuclear Information System (INIS)
1987-05-01
This Study, the Emergency Management Functional Requirements Study (EMFRS), identifies the physical environment, information resources, and equipment required in the DOE Headquarters Emergency Operations Center (EOC) to support the DOE staff in managing an emergency. It is the first step toward converting the present Forrestal EOC into a practical facility that will function well in each of the highly diverse types of emergencies in which the Department could be involved. 2 figs
Genetic modulation of energy metabolism in birds through mitochondrial function
Tieleman, B. Irene; Versteegh, Maaike A.; Fries, Anthony; Helm, Barbara; Dingemanse, Niels J.; Gibbs, H. Lisle; Williams, Joseph B.
2009-01-01
Despite their central importance for the evolution of physiological variation, the genetic mechanisms that determine energy expenditure in animals have largely remained unstudied. We used quantitative genetics to confirm that both mass-specific and whole-organism basal metabolic rate (BMR) were
Bubin, Sergiy; Adamowicz, Ludwik
2008-03-01
In this work we consider explicitly correlated complex Gaussian basis functions for expanding the wave function of an N-particle system with the L =1 total orbital angular momentum. We derive analytical expressions for various matrix elements with these basis functions including the overlap, kinetic energy, and potential energy (Coulomb interaction) matrix elements, as well as matrix elements of other quantities. The derivatives of the overlap, kinetic, and potential energy integrals with respect to the Gaussian exponential parameters are also derived and used to calculate the energy gradient. All the derivations are performed using the formalism of the matrix differential calculus that facilitates a way of expressing the integrals in an elegant matrix form, which is convenient for the theoretical analysis and the computer implementation. The new method is tested in calculations of two systems: the lowest P state of the beryllium atom and the bound P state of the positronium molecule (with the negative parity). Both calculations yielded new, lowest-to-date, variational upper bounds, while the number of basis functions used was significantly smaller than in previous studies. It was possible to accomplish this due to the use of the analytic energy gradient in the minimization of the variational energy.
Bubin, Sergiy; Adamowicz, Ludwik
2008-03-21
In this work we consider explicitly correlated complex Gaussian basis functions for expanding the wave function of an N-particle system with the L=1 total orbital angular momentum. We derive analytical expressions for various matrix elements with these basis functions including the overlap, kinetic energy, and potential energy (Coulomb interaction) matrix elements, as well as matrix elements of other quantities. The derivatives of the overlap, kinetic, and potential energy integrals with respect to the Gaussian exponential parameters are also derived and used to calculate the energy gradient. All the derivations are performed using the formalism of the matrix differential calculus that facilitates a way of expressing the integrals in an elegant matrix form, which is convenient for the theoretical analysis and the computer implementation. The new method is tested in calculations of two systems: the lowest P state of the beryllium atom and the bound P state of the positronium molecule (with the negative parity). Both calculations yielded new, lowest-to-date, variational upper bounds, while the number of basis functions used was significantly smaller than in previous studies. It was possible to accomplish this due to the use of the analytic energy gradient in the minimization of the variational energy.
Functional zinc oxide nanostructures for electronic and energy applications
Prasad, Abhishek
ZnO has proven to be a multifunctional material with important nanotechnological applications. ZnO nanostructures can be grown in various forms such as nanowires, nanorods, nanobelts, nanocombs etc. In this work, ZnO nanostructures are grown in a double quartz tube configuration thermal Chemical Vapor Deposition (CVD) system. We focus on functionalized ZnO Nanostructures by controlling their structures and tuning their properties for various applications. The following topics have been investigated: (1) We have fabricated various ZnO nanostructures using a thermal CVD technique. The growth parameters were optimized and studied for different nanostructures. (2) We have studied the application of ZnO nanowires (ZnONWs) for field effect transistors (FETs). Unintentional n-type conductivity was observed in our FETs based on as-grown ZnO NWs. We have then shown for the first time that controlled incorporation of hydrogen into ZnO NWs can introduce p-type characters to the nanowires. We further found that the n-type behaviors remained, leading to the ambipolar behaviors of hydrogen incorporated ZnO NWs. Importantly, the detected p- and n- type behaviors are stable for longer than two years when devices were kept in ambient conditions. All these can be explained by an ab initio model of Zn vacancy-Hydrogen complexes, which can serve as the donor, acceptors, or green photoluminescence quencher, depend on the number of hydrogen atoms involved. (3) Next ZnONWs were tested for electron field emission. We focus on reducing the threshold field (Eth) of field emission from non-aligned ZnO NWs. As encouraged by our results on enhancing the conductivity of ZnO NWs by hydrogen annealing described in Chapter 3, we have studied the effect of hydrogen annealing for improving field emission behavior of our ZnO NWs. We found that optimally annealed ZnO NWs offered much lower threshold electric field and improved emission stability. We also studied field emission from ZnO NWs at moderate
Energy Availability and Reproductive Function in Female Endurance Athletes
DEFF Research Database (Denmark)
Melin, Anna Katarina
and reduced EA, as well as those with oligomenorrhea/FHA, had lower RMR compared to those with either current optimal EA or eumenorrheic athletes. Furthermore, athletes with secondary FHA had increased work efficiency compared to eumenorrheic subjects, indicating a more profound metabolic adaptation in female...... athletes with clinical menstrual dysfunction. All three Triad conditions were common in this group of athletes, despite a normal BMI range and body composition. Furthermore, issues and physiological symptoms related to current low and reduced EA and oligomenorrhea/FHA were not limited to impaired bone...... health, but also included hypoglycaemia, hypercholesterolemia, and hypotension. The results indicated that diets lower in energy density, fat content, compact carbohydrate-rich foods and energy-containing drinks, together with higher fibre content, were associated with current low and reduced EA...
The role of dual-energy computed tomography in the assessment of pulmonary function
Energy Technology Data Exchange (ETDEWEB)
Hwang, Hye Jeon [Department of Radiology, Hallym University College of Medicine, Hallym University Sacred Heart Hospital, 22, Gwanpyeong-ro 170beon-gil, Dongan-gu, Anyang-si, Gyeonggi-do 431-796 (Korea, Republic of); Hoffman, Eric A. [Departments of Radiology, Medicine, and Biomedical Engineering, University of Iowa, 200 Hawkins Dr, CC 701 GH, Iowa City, IA 52241 (United States); Lee, Chang Hyun; Goo, Jin Mo [Department of Radiology, Seoul National University College of Medicine, 103 Daehak-ro, Jongno-gu, Seoul 110-799 (Korea, Republic of); Levin, David L. [Department of Radiology, Mayo Clinic College of Medicine, 200 First Street, SW, Rochester, MN 55905 (United States); Kauczor, Hans-Ulrich [Diagnostic and Interventional Radiology, University Hospital Heidelberg, Im Neuenheimer Feld 400, 69120 Heidelberg (Germany); Translational Lung Research Center Heidelberg (TLRC), Member of the German Center for Lung Research (DZL), Im Neuenheimer Feld 400, 69120 Heidelberg (Germany); Seo, Joon Beom, E-mail: seojb@amc.seoul.kr [Department of Radiology and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, 388-1, Pungnap 2-dong, Songpa-ku, Seoul, 05505 (Korea, Republic of)
2017-01-15
Highlights: • The dual-energy CT technique enables the differentiation of contrast materials with material decomposition algorithm. • Pulmonary functional information can be evaluated using dual-energy CT with anatomic CT information, simultaneously. • Pulmonary functional information from dual-energy CT can improve diagnosis and severity assessment of diseases. - Abstract: The assessment of pulmonary function, including ventilation and perfusion status, is important in addition to the evaluation of structural changes of the lung parenchyma in various pulmonary diseases. The dual-energy computed tomography (DECT) technique can provide the pulmonary functional information and high resolution anatomic information simultaneously. The application of DECT for the evaluation of pulmonary function has been investigated in various pulmonary diseases, such as pulmonary embolism, asthma and chronic obstructive lung disease and so on. In this review article, we will present principles and technical aspects of DECT, along with clinical applications for the assessment pulmonary function in various lung diseases.
Formation energies of rutile metal dioxides using density functional theory
DEFF Research Database (Denmark)
Martinez, Jose Ignacio; Hansen, Heine Anton; Rossmeisl, Jan
2009-01-01
We apply standard density functional theory at the generalized gradient approximation (GGA) level to study the stability of rutile metal oxides. It is well known that standard GGA exchange and correlation in some cases is not sufficient to address reduction and oxidation reactions. Especially...... and due to a more accurate description of exchange for this particular GGA functional compared to PBE. Furthermore, we would expect the self-interaction problem to be largest for the most localized d orbitals; that means the late 3d metals and since Co, Fe, Ni, and Cu do not form rutile oxides...
Expanded explorations into the optimization of an energy function for protein design
Huang, Yao-ming; Bystroff, Christopher
2014-01-01
Nature possesses a secret formula for the energy as a function of the structure of a protein. In protein design, approximations are made to both the structural representation of the molecule and to the form of the energy equation, such that the existence of a general energy function for proteins is by no means guaranteed. Here we present new insights towards the application of machine learning to the problem of finding a general energy function for protein design. Machine learning requires the definition of an objective function, which carries with it the implied definition of success in protein design. We explored four functions, consisting of two functional forms, each with two criteria for success. Optimization was carried out by a Monte Carlo search through the space of all variable parameters. Cross-validation of the optimized energy function against a test set gave significantly different results depending on the choice of objective function, pointing to relative correctness of the built-in assumptions. Novel energy cross-terms correct for the observed non-additivity of energy terms and an imbalance in the distribution of predicted amino acids. This paper expands on the work presented at ACM-BCB, Orlando FL , October 2012. PMID:24384706
Energy Technology Data Exchange (ETDEWEB)
Moon, C.K. [Korea Energy Economics Institute, Euiwang (Korea, Republic of)
1997-08-01
If the necessity of careful study on energy function is mentioned, it should be stressed that energy investment not only needs a long gestation period but also, acts as the bottleneck in the production capacity of an economy when investment is not enough. Thereby, the adverse effect of an energy supply shortage is very big. Especially, the replacement/supplemental relationship between energy and capital which corresponds to the movement on the iso-quanta curve is believed to have a direct relation with the answer as to whether long-term economic development would be possible under an energy crisis and its influence on technology selection. Furthermore, the advantages of technological advances which correspond to the movement on the iso-quanta curve has a direct relation with the question whether long-term economic development would be possible under an energy crisis depending on whether its direction is toward energy-saving or energy-consuming. This study tackles the main issues and outlines of the quantitative approach method based on the accounting approach method for modeling energy demand, quantitative economics approach method, and production model. In order to model energy demand of the Korean manufacturing industry, related data was established and a positive analytical model is completed and presented based on these. 122 refs., 10 tabs.
Magnetic field effects on the quantum wire energy spectrum and Green's function
International Nuclear Information System (INIS)
Morgenstern Horing, Norman J.
2010-01-01
We analyze the energy spectrum and propagation of electrons in a quantum wire on a 2D host medium in a normal magnetic field, representing the wire by a 1D Dirac delta function potential which would support just a single subband state in the absence of the magnetic field. The associated Schroedinger Green's function for the quantum wire is derived in closed form in terms of known functions and the Landau quantized subband energy spectrum is examined.
Energy substrates to support glutamatergic and GABAergic synaptic function
DEFF Research Database (Denmark)
Schousboe, Arne; Bak, Lasse K; Sickmann, Helle M
2007-01-01
under normal conditions is glucose but at the cellular level, i.e., neurons and astrocytes, lactate may play an important role as well. In addition to this the possibility exists that glycogen, which functions as a glucose storage molecule and which is only present in astrocytes, could play a role...
Energy vs. density on paths toward exact density functionals
DEFF Research Database (Denmark)
Kepp, Kasper Planeta
2018-01-01
Recently, the progression toward more exact density functional theory has been questioned, implying a need for more formal ways to systematically measure progress, i.e. a “path”. Here I use the Hohenberg-Kohn theorems and the definition of normality by Burke et al. to define a path toward exactness...
Of energy and the economy. Theory and evidence of their functional relationships
Energy Technology Data Exchange (ETDEWEB)
Chang, V.
2007-07-01
The author of the contribution under consideration offers a set of explicit functional relationships that link energy and the economy. Despite the reliance on energy permeating the whole economy, no such complete relationships had been presented before. The relevant questions are: (a) How related are energy and the economy? (b) What role does energy play in the economic growth? Under this aspect, the author theorizes the role of energy and then tests it with economic models, using data from 16 OECD countries from 1980 to 2001. The main results are the following: (a) Energy is a cross-country representative good whose prices are equalized when converted to a reference currency. Thus, energy prices satisfy the purchasing power parity. For all but one country, the half life of the real exchange rate is less than a year and as low as six months, shorter than those derived by other real exchange rate measures; (b) Considering energy a cross-time representative good, a country's utility function is inversely proportional to both its income share of energy and its energy price. The author obtains an explicit, unified two-dimensional (cross countries and time) production function with energy and non-energy as the two inputs; (c) The author concludes a cross-country parity relationship for income shares of energy, similar to that for energy prices. Furthermore, the author provides an intertemporal connection between the trajectory of the income share of energy and the productivity growth of the economy; (d) The author demonstrates the tradeoffs between energy efficiency and economic wellbeing, with the energy price being the medium of the tradeoffs.
Four-point correlation function of stress-energy tensors in N=4 superconformal theories
Korchemsky, G P
2015-01-01
We derive the explicit expression for the four-point correlation function of stress-energy tensors in four-dimensional N=4 superconformal theory. We show that it has a remarkably simple and suggestive form allowing us to predict a large class of four-point correlation functions involving the stress-energy tensor and other conserved currents. We then apply the obtained results on the correlation functions to computing the energy-energy correlations, which measure the flow of energy in the final states created from the vacuum by a source. We demonstrate that they are given by a universal function independent of the choice of the source. Our analysis relies only on N=4 superconformal symmetry and does not use the dynamics of the theory.
Nonlocal exchange and kinetic-energy density functionals for electronic systems
International Nuclear Information System (INIS)
Glossman, M.D.; Rubio, A.; Balbas, L.C.; Alonso, J.A.
1992-01-01
The nonlocal weighted density approximation (WDA) to the exchange and kinetic-energy functionals of many electron systems proposed several years ago by Alonso and Girifalco is used to compute, within the framework of density functional theory, the ground-state electronic density and total energy of noble gas atoms and of neutral jellium-like sodium clusters containing up to 500 atoms. These results are compared with analogous calculations using the well known Thomas-Fermi-Weizsacker-Dirac (TFWD) approximations for the kinetic (TFW) and exchange (D) energy density functionals. An outstanding improvement of the total and exchange energies, of the density at the nucleus and of the expectation values is obtained for atoms within the WDA scheme. For sodium clusters the authors notice a sizeable contribution of the nonlocal effects to the total energy and to the density profiles. In the limit of very large clusters these effects should affect the surface energy of the bulk metal
Analytical potential energy function for the Br + H{sub 2} system
Energy Technology Data Exchange (ETDEWEB)
Kurosaki, Yuzuru [Japan Atomic Energy Research Inst., Kizu, Kyoto (Japan). Kansai Research Establishment
2001-10-01
Analytical functions with a many-body expansion for the ground and first-excited-state potential energy surfaces for the Br+H{sub 2} system are newly presented in this work. These functions describe the abstraction and exchange reactions qualitatively well, although it has been found that the function for the ground-state potential surface is still quantitatively unsatisfactory. (author)
Equation satisfied by electron-electron mutual Coulomb repulsion energy density functional
Joubert, Daniel P.
2011-01-01
The electron-electron mutual Coulomb repulsion energy density functional satisfies an equation that links functionals and functional derivatives at N-electron and (N-1)-electron densities for densities determined from the same adiabatic scaled external potential for the N-electron system.
Ponizovskiy, Michail R
2016-01-01
Interactions between nucleus and mitochondria functions induce the mechanism of maintenance stability of cellular internal energy according to the first law of thermodynamics in able-bodied cells and changes the mechanisms of maintenance stability of cellular internal energy creating a transition stationary state of ablebodied cells into quasi-stationary pathologic states of acute inflammation transiting then into chronic inflammation and then transmuting into cancer metabolism. The mechanisms' influences of intruding etiologic pathologic agents (microbe, virus, etc.) lead to these changes of energy interactions between nucleus and mitochondria functions causing general acute inflammation, then passing into local chronic inflammation, and reversing into cancer metabolism transmutation. Interactions between biochemical processes and biophysical processes of cellular capacitors' operations create a supplementary mechanism of maintenance stability of cellular internal energy in the norm and in pathology. Discussion of some scientific works eliminates doubts of the authors of these works.
Evaluation of the Effects of Different Energy Drinks and Coffee on Endothelial Function.
Molnar, Janos; Somberg, John C
2015-11-01
Endothelial function plays an important role in circulatory physiology. There has been differing reports on the effect of energy drink on endothelial function. We set out to evaluate the effect of 3 energy drinks and coffee on endothelial function. Endothelial function was evaluated in healthy volunteers using a device that uses digital peripheral arterial tonometry measuring endothelial function as the reactive hyperemia index (RHI). Six volunteers (25 ± 7 years) received energy drink in a random order at least 2 days apart. Drinks studied were 250 ml "Red Bull" containing 80 mg caffeine, 57 ml "5-hour Energy" containing 230 mg caffeine, and a can of 355 ml "NOS" energy drink containing 120 mg caffeine. Sixteen volunteers (25 ± 5 years) received a cup of 473 ml coffee containing 240 mg caffeine. Studies were performed before drink (baseline) at 1.5 and 4 hours after drink. Two of the energy drinks (Red Bull and 5-hour Energy) significantly improved endothelial function at 4 hours after drink, whereas 1 energy drink (NOS) and coffee did not change endothelial function significantly. RHI increased by 82 ± 129% (p = 0.028) and 63 ± 37% (p = 0.027) after 5-hour Energy and Red Bull, respectively. The RHI changed after NOS by 2 ± 30% (p = 1.000) and by 7 ± 30% (p = 1.000) after coffee. In conclusion, some energy drinks appear to significantly improve endothelial function. Caffeine does not appear to be the component responsible for these differences. Copyright © 2015 Elsevier Inc. All rights reserved.
Approximated calculation of the vacuum wave function and vacuum energy of the LGT with RPA method
International Nuclear Information System (INIS)
Hui Ping
2004-01-01
The coupled cluster method is improved with the random phase approximation (RPA) to calculate vacuum wave function and vacuum energy of 2 + 1 - D SU(2) lattice gauge theory. In this calculating, the trial wave function composes of single-hollow graphs. The calculated results of vacuum wave functions show very good scaling behaviors at weak coupling region l/g 2 >1.2 from the third order to the sixth order, and the vacuum energy obtained with RPA method is lower than the vacuum energy obtained without RPA method, which means that this method is a more efficient one
Image Fusion Based on the \\({\\Delta ^{ - 1}} - T{V_0}\\ Energy Function
Directory of Open Access Journals (Sweden)
Qiwei Xie
2014-11-01
Full Text Available This article proposes a \\({\\Delta^{-1}}-T{V_0}\\ energy function to fuse a multi-spectral image with a panchromatic image. The proposed energy function consists of two components, a \\(TV_0\\ component and a \\(\\Delta^{-1}\\ component. The \\(TV_0\\ term uses the sparse priority to increase the detailed spatial information; while the \\({\\Delta ^{ - 1}}\\ term removes the block effect of the multi-spectral image. Furthermore, as the proposed energy function is non-convex, we also adopt an alternative minimization algorithm and the \\(L_0\\ gradient minimization to solve it. Experimental results demonstrate the improved performance of the proposed method over existing methods.
Experimental parameterization of an energy function for the simulation of unfolded proteins
DEFF Research Database (Denmark)
Norgaard, A.B.; Ferkinghoff-Borg, Jesper; Lindorff-Larsen, K.
2008-01-01
The determination of conformational preferences in unfolded and disordered proteins is an important challenge in structural biology. We here describe an algorithm to optimize energy functions for the simulation of unfolded proteins. The procedure is based on the maximum likelihood principle and e...... and can be applied to a range of experimental data and energy functions including the force fields used in molecular dynamics simulations.......The determination of conformational preferences in unfolded and disordered proteins is an important challenge in structural biology. We here describe an algorithm to optimize energy functions for the simulation of unfolded proteins. The procedure is based on the maximum likelihood principle...
Functional Domain Walls as Active Elements for Energy Technology
Energy Technology Data Exchange (ETDEWEB)
Wu, Junqiao [Univ. of California, Berkeley, CA (United States)
2016-10-12
In the past five years in the duration of this project (July 2011-July 2016), we have made a wide range of achievements in both basic research and energy applications along the direction planned in the original proposal. These achievements were reflected by 13 articles published in peer-reviewed journals including Nature Communications, Nano Letters, etc., and one currently in revision at Science. These papers have been accumulatively cited for more than 660 times as of October 2016, according to Web of Science statistics. Specifically, we have made impactful discoveries in the following fields. Basic Research. We have investigated in depth the materials physics of the representative quantum material, VO_{2}, on which most of our project is anchored. We have discovered that independent diffusion of heat and charge in the absence of quasiparticles in metallic VO_{2} leads to an anomalously low electronic thermal conductivity, dramatically violating the Wiedemann-Franz law, which is a robust law governing behavior of normal conductors stating that free electrons transport heat proportionally to the charge they transport. In addition, we have discovered a peculiar thermal rectification effect based on its phase transition, as well as a gating response of the phase transition. In parallel to the work on VO_{2}, we have also made breakthroughs in investigation of transition metal dichalcogenides (TMDs): we have experimentally demonstrate a strong anisotropy in in-plane thermal conductivity of black phosphorous, discovered a new, unusual member of the TMDs family, ReS_{2}, where the bulk behaves as monolayers due to electronic and vibrational decoupling, unusual interaction between physi-sorbed molecules and 2D semiconductors, and thermally driven crossover from indirect toward direct bandgap in some 2D TMDs. Applications. Based on the understanding and knowledge gained from the basic investigation, we have developed novel tools and
Functional nanomaterials and devices for electronics, sensors and energy harvesting
Balestra, Francis; Kilchytska, Valeriya; Flandre, Denis
2014-01-01
This book contains reviews of recent experimental and theoretical results related to nanomaterials. It focuses on novel functional materials and nanostructures in combination with silicon on insulator (SOI) devices, as well as on the physics of new devices and sensors, nanostructured materials and nano scaled device characterization. Special attention is paid to fabrication and properties of modern low-power, high-performance, miniaturized, portable sensors in a wide range of applications such as telecommunications, radiation control, biomedical instrumentation and chemical analysis. In this book, new approaches exploiting nanotechnologies (such as UTBB FD SOI, Fin FETs, nanowires, graphene or carbon nanotubes on dielectric) to pave a way between “More Moore” and “More than Moore” are considered, in order to create different kinds of sensors and devices which will consume less electrical power, be more portable and totally compatible with modern microelectronics products.
International Nuclear Information System (INIS)
Oruskaya, M.
2002-01-01
Materials collected (presented) in the paper introduce to (familiarise) the audience with the main forms, methods and phases of the state regulation of energy industry in Ukraine in the period of transition to market economy. Special attention was paid to the following aspects: 1. Necessity and history of establishment of special regulatory body in Ukraine - The National Electricity Regulatory Commission (NERC); 2. The main tasks and authorities of NERC according to the Ukraine Law on Energy Sector; 3. Regulation mechanisms of the main processes in the energy industry used by the Commission on the current level of energy sector development and economic results of its introduction; 4. Problems with functioning of the wholesale energy market specifically as the main component of the Ukraine energy industry and trends of future development (improvement of energy industry's financial situation, intensification of competition between energy producers and suppliers, improvement of tariff and investment policies, etc.); 5. Necessity and ways of future improvement of the standards and legal basis for regulation in Ukraine. (author)
Azobenzene-functionalized carbon nanotubes as high-energy density solar thermal fuels.
Kolpak, Alexie M; Grossman, Jeffrey C
2011-08-10
Solar thermal fuels, which reversibly store solar energy in molecular bonds, are a tantalizing prospect for clean, renewable, and transportable energy conversion/storage. However, large-scale adoption requires enhanced energy storage capacity and thermal stability. Here we present a novel solar thermal fuel, composed of azobenzene-functionalized carbon nanotubes, with the volumetric energy density of Li-ion batteries. Our work also demonstrates that the inclusion of nanoscale templates is an effective strategy for design of highly cyclable, thermally stable, and energy-dense solar thermal fuels.
Correlation energy functional within the GW -RPA: Exact forms, approximate forms, and challenges
Ismail-Beigi, Sohrab
2010-05-01
In principle, the Luttinger-Ward Green’s-function formalism allows one to compute simultaneously the total energy and the quasiparticle band structure of a many-body electronic system from first principles. We present approximate and exact expressions for the correlation energy within the GW -random-phase approximation that are more amenable to computation and allow for developing efficient approximations to the self-energy operator and correlation energy. The exact form is a sum over differences between plasmon and interband energies. The approximate forms are based on summing over screened interband transitions. We also demonstrate that blind extremization of such functionals leads to unphysical results: imposing physical constraints on the allowed solutions (Green’s functions) is necessary. Finally, we present some relevant numerical results for atomic systems.
Energy consumption of building related energy functions in houses and utility buildings
International Nuclear Information System (INIS)
Van Arkel, W.G.; Jeeninga, H.; Menkveld, M.; Ruijg, G.J.
1999-11-01
This study investigates the development of the use of electricity and natural gas in houses and buildings until 2010. For the domestic sector it is studied how much energy is used now and will be used in future for heating, for production of hot water, for lighting, for ventilation and for cooling. For different sorts of buildings (shops, hospitals, schools, offices, restaurants) it has been determined how much gas will be used for heating, for hot water production and by humidifiers. It has also been calculated how much electricity will be used for lighting, ventilation, cooling and humidifying. The influence of higher and lower energy prices on the amount of use has been studied. Experts have been asked to give their opinions on trends in the use of buildings and the role of new technologies. The influence of these ideas on the use of energy has been calculated. 44 refs
Swart, M.; Sola, M.; Bickelhaupt, F.M.
2007-01-01
We have carried out a detailed evaluation of the performance of all classes of density functional theory (DFT) for describing the potential energy surface (PES) of a wide range of nucleophilic substitution (S
Single-particle energies and density of states in density functional theory
van Aggelen, H.; Chan, G. K.-L.
2015-07-01
Time-dependent density functional theory (TD-DFT) is commonly used as the foundation to obtain neutral excited states and transition weights in DFT, but does not allow direct access to density of states and single-particle energies, i.e. ionisation energies and electron affinities. Here we show that by extending TD-DFT to a superfluid formulation, which involves operators that break particle-number symmetry, we can obtain the density of states and single-particle energies from the poles of an appropriate superfluid response function. The standard Kohn- Sham eigenvalues emerge as the adiabatic limit of the superfluid response under the assumption that the exchange- correlation functional has no dependence on the superfluid density. The Kohn- Sham eigenvalues can thus be interpreted as approximations to the ionisation energies and electron affinities. Beyond this approximation, the formalism provides an incentive for creating a new class of density functionals specifically targeted at accurate single-particle eigenvalues and bandgaps.
Frequency response function of motors for switching noise energy with a new experimental approach
International Nuclear Information System (INIS)
Kim, Hyunsu; Yoon, Jong-Yun
2017-01-01
Switching energy in electrical vehicles can create serious noise from the motors. However, the characteristics of switching noise in vehicle motors are not clear due to the complexity of measuring them. This study proposes a new experimental method to investigate the switching noise energy of a vehicle motor based on frequency response functions. A function generator-amplifier system is used to gen- erate the switching energy instead of the complex battery-inverter system that has previously been used to examine the noise energy characteristics. Even though newly adapted experimental method is simple, the switching noise energy was explicitly investigated under various input signals. Thus, this simple new method can be used to investigate the dynamic characteristics of noise energy in a vehicle motor
Frequency response function of motors for switching noise energy with a new experimental approach
Energy Technology Data Exchange (ETDEWEB)
Kim, Hyunsu [Ensemble Center for Automotive Research, Seoul (Korea, Republic of); Yoon, Jong-Yun [Incheon National University, Incheon (Korea, Republic of)
2017-06-15
Switching energy in electrical vehicles can create serious noise from the motors. However, the characteristics of switching noise in vehicle motors are not clear due to the complexity of measuring them. This study proposes a new experimental method to investigate the switching noise energy of a vehicle motor based on frequency response functions. A function generator-amplifier system is used to gen- erate the switching energy instead of the complex battery-inverter system that has previously been used to examine the noise energy characteristics. Even though newly adapted experimental method is simple, the switching noise energy was explicitly investigated under various input signals. Thus, this simple new method can be used to investigate the dynamic characteristics of noise energy in a vehicle motor.
Nuclear energy density functional from chiral pion-nucleon dynamics revisited
Kaiser, N.; Weise, W.
2009-01-01
We use a recently improved density-matrix expansion to calculate the nuclear energy density functional in the framework of in-medium chiral perturbation theory. Our calculation treats systematically the effects from $1\\pi$-exchange, iterated $1\\pi$-exchange, and irreducible $2\\pi$-exchange with intermediate $\\Delta$-isobar excitations, including Pauli-blocking corrections up to three-loop order. We find that the effective nucleon mass $M^*(\\rho)$ entering the energy density functional is iden...
Towards improved local hybrid functionals by calibration of exchange-energy densities
International Nuclear Information System (INIS)
Arbuznikov, Alexei V.; Kaupp, Martin
2014-01-01
A new approach for the calibration of (semi-)local and exact exchange-energy densities in the context of local hybrid functionals is reported. The calibration functions are derived from only the electron density and its spatial derivatives, avoiding spatial derivatives of the exact-exchange energy density or other computationally unfavorable contributions. The calibration functions fulfill the seven more important out of nine known exact constraints. It is shown that calibration improves substantially the definition of a non-dynamical correlation energy term for generalized gradient approximation (GGA)-based local hybrids. Moreover, gauge artifacts in the potential-energy curves of noble-gas dimers may be corrected by calibration. The developed calibration functions are then evaluated for a large range of energy-related properties (atomization energies, reaction barriers, ionization potentials, electron affinities, and total atomic energies) of three sets of local hybrids, using a simple one-parameter local-mixing. The functionals are based on (a) local spin-density approximation (LSDA) or (b) Perdew-Burke-Ernzerhof (PBE) exchange and correlation, and on (c) Becke-88 (B88) exchange and Lee-Yang-Parr (LYP) correlation. While the uncalibrated GGA-based functionals usually provide very poor thermochemical data, calibration allows a dramatic improvement, accompanied by only a small deterioration of reaction barriers. In particular, an optimized BLYP-based local-hybrid functional has been found that is a substantial improvement over the underlying global hybrids, as well as over previously reported LSDA-based local hybrids. It is expected that the present calibration approach will pave the way towards new generations of more accurate hyper-GGA functionals based on a local mixing of exchange-energy densities
DEFF Research Database (Denmark)
Cornaton, Y.; Stoyanova, A.; Jensen, Hans Jørgen Aagaard
2013-01-01
of the noninteracting Kohn-Sham one. When second-order corrections to the density are neglected, the energy expression reduces to a range-separated double-hybrid (RSDH) type of functional, RSDHf, where "f" stands for "full-range integrals" as the regular full-range interaction appears explicitly in the energy...
International Nuclear Information System (INIS)
Bluemlein, J.
1993-08-01
The possibilities to measure structure functions, to extract parton distributions, and to measure α s and Λ QCD in current and future high energy deep inelastic scattering experiments are reviewed. A comparison is given for experiments at HERA, an ep option at LEP xLHC, and a high energy neutrino experiment. (orig.)
Cascade-probabilistic function with taking unto account energy losses of ions. Chapter 3
International Nuclear Information System (INIS)
1998-01-01
Mathematical simulation of cascade-probabilistic functions (CPF) for ions with taking into account of energy losses is carried out. Recommendations for CPF calculation on computer are given. Influence of both the interaction number on CPF domain and the interaction depth on CPF domain are determined. Contribution of energy losses into simplest CPF is estimated. Algorithm of radiation defects concentration calculation under ion irradiation with taking into consideration energy losses is cited
Khvostichenko, Daria; Choi, Andrew; Boulatov, Roman
2008-04-24
We investigated the effect of several computational variables, including the choice of the basis set, application of symmetry constraints, and zero-point energy (ZPE) corrections, on the structural parameters and predicted ground electronic state of model 5-coordinate hemes (iron(II) porphines axially coordinated by a single imidazole or 2-methylimidazole). We studied the performance of B3LYP and B3PW91 with eight Pople-style basis sets (up to 6-311+G*) and B97-1, OLYP, and TPSS functionals with 6-31G and 6-31G* basis sets. Only hybrid functionals B3LYP, B3PW91, and B97-1 reproduced the quintet ground state of the model hemes. With a given functional, the choice of the basis set caused up to 2.7 kcal/mol variation of the quintet-triplet electronic energy gap (DeltaEel), in several cases, resulting in the inversion of the sign of DeltaEel. Single-point energy calculations with triple-zeta basis sets of the Pople (up to 6-311G++(2d,2p)), Ahlrichs (TZVP and TZVPP), and Dunning (cc-pVTZ) families showed the same trend. The zero-point energy of the quintet state was approximately 1 kcal/mol lower than that of the triplet, and accounting for ZPE corrections was crucial for establishing the ground state if the electronic energy of the triplet state was approximately 1 kcal/mol less than that of the quintet. Within a given model chemistry, effects of symmetry constraints and of a "tense" structure of the iron porphine fragment coordinated to 2-methylimidazole on DeltaEel were limited to 0.3 kcal/mol. For both model hemes the best agreement with crystallographic structural data was achieved with small 6-31G and 6-31G* basis sets. Deviation of the computed frequency of the Fe-Im stretching mode from the experimental value with the basis set decreased in the order: nonaugmented basis sets, basis sets with polarization functions, and basis sets with polarization and diffuse functions. Contraction of Pople-style basis sets (double-zeta or triple-zeta) affected the results
Applications of Skyrme energy-density functional to fusion reactions spanning the fusion barriers
International Nuclear Information System (INIS)
Liu Min; Wang, Ning; Li Zhuxia; Wu Xizhen; Zhao Enguang
2006-01-01
The Skyrme energy density functional has been applied to the study of heavy-ion fusion reactions. The barriers for fusion reactions are calculated by the Skyrme energy density functional with proton and neutron density distributions determined by using restricted density variational (RDV) method within the same energy density functional together with semi-classical approach known as the extended semi-classical Thomas-Fermi method. Based on the fusion barrier obtained, we propose a parametrization of the empirical barrier distribution to take into account the multi-dimensional character of real barrier and then apply it to calculate the fusion excitation functions in terms of barrier penetration concept. A large number of measured fusion excitation functions spanning the fusion barriers can be reproduced well. The competition between suppression and enhancement effects on sub-barrier fusion caused by neutron-shell-closure and excess neutron effects is studied
Patra, Abhilash; Jana, Subrata; Samal, Prasanjit
2018-04-01
The construction of meta generalized gradient approximations based on the density matrix expansion (DME) is considered as one of the most accurate techniques to design semilocal exchange energy functionals in two-dimensional density functional formalism. The exchange holes modeled using DME possess unique features that make it a superior entity. Parameterized semilocal exchange energy functionals based on the DME are proposed. The use of different forms of the momentum and flexible parameters is to subsume the non-uniform effects of the density in the newly constructed semilocal functionals. In addition to the exchange functionals, a suitable correlation functional is also constructed by working upon the local correlation functional developed for 2D homogeneous electron gas. The non-local effects are induced into the correlation functional by a parametric form of one of the newly constructed exchange energy functionals. The proposed functionals are applied to the parabolic quantum dots with a varying number of confined electrons and the confinement strength. The results obtained with the aforementioned functionals are quite satisfactory, which indicates why these are suitable for two-dimensional quantum systems.
International Nuclear Information System (INIS)
Hupin, G; Lacroix, D; Bender, M
2011-01-01
The Multi-Reference Energy Density Functional (MR-EDF) approach (also called configuration mixing or Generator Coordinate Method), that is commonly used to treat pairing in finite nuclei and project onto particle number, is re-analyzed. It is shown that, under certain conditions, the MR-EDF energy can be interpreted as a functional of the one-body density matrix of the projected state with good particle number. Based on this observation, we propose a new approach, called Symmetry-Conserving EDF (SC-EDF), where the breaking and restoration of symmetry are accounted for simultaneously. We show, that such an approach is free from pathologies recently observed in MR-EDF and can be used with a large flexibility on the density dependence of the functional.
International Nuclear Information System (INIS)
Yang, W.; Wu, H.; Cao, L.
2012-01-01
More and more MOX fuels are used in all over the world in the past several decades. Compared with UO 2 fuel, it contains some new features. For example, the neutron spectrum is harder and more resonance interference effects within the resonance energy range are introduced because of more resonant nuclides contained in the MOX fuel. In this paper, the wavelets scaling function expansion method is applied to study the resonance behavior of plutonium isotopes within MOX fuel. Wavelets scaling function expansion continuous-energy self-shielding method is developed recently. It has been validated and verified by comparison to Monte Carlo calculations. In this method, the continuous-energy cross-sections are utilized within resonance energy, which means that it's capable to solve problems with serious resonance interference effects without iteration calculations. Therefore, this method adapts to treat the MOX fuel resonance calculation problem natively. Furthermore, plutonium isotopes have fierce oscillations of total cross-section within thermal energy range, especially for 240 Pu and 242 Pu. To take thermal resonance effect of plutonium isotopes into consideration the wavelet scaling function expansion continuous-energy resonance calculation code WAVERESON is enhanced by applying the free gas scattering kernel to obtain the continuous-energy scattering source within thermal energy range (2.1 eV to 4.0 eV) contrasting against the resonance energy range in which the elastic scattering kernel is utilized. Finally, all of the calculation results of WAVERESON are compared with MCNP calculation. (authors)
Electronic energy distribution function at high electron swarm energies in neon
International Nuclear Information System (INIS)
Brown, K.L.; Fletcher, J.
1995-01-01
Electron swarms moving through a gas under the influence of an applied electric field have been extensively investigated. Swarms at high energies, as measured by the ratio of the applied field to the gas number density, E/N, which are predominant in many applications have, in general, been neglected. Discharges at E/N in the range 300 0 < 133 Pa using a differentially pumped vacuum system in which the swarm electrons are extracted from the discharge and energy analysed in both a parallel plate retarded potential analyser and a cylindrical electrostatic analyser. Both pre-breakdown and post-breakdown discharges have been studied. Initial results indicate that as the discharge traverses breakdown no sudden change in the nature of the discharge occurs and that the discharge can be described by both a Monte Carlo simulation and by a Boltzmann treatment given by Phelps et al. (1987). 18 refs., 8 figs
The ground state energy of 3He droplet in the LOCV framework
International Nuclear Information System (INIS)
Modarres, M.; Motahari, S.; Rajabi, A.
2012-01-01
The (extended) lowest order constrained variational method was used to calculate the ground state energy of liquid helium 3 ( 3 He) droplets at zero temperature. Different types of density distribution profiles, such as the Gaussian, the Quasi-Gaussian and the Woods-Saxon were used. It was shown that at least, on average, near 20 3 He atoms are needed to get the bound state for 3 He liquid droplet. Depending on the choice of the density profiles and the atomic radius of 3 He, the above estimate can increase to 300. Our calculated ground state energy and the number of atoms in liquid 3 He droplet were compared with those of Variational Monte Carlo method, Diffusion Monte Carlo method and Density Functional Theory, for which a reasonable agreement was found.
International Nuclear Information System (INIS)
Patsidis, A.C.; Kalaitzidou, K.; Psarras, G.C.
2012-01-01
Barium titanate/epoxy and exfoliated graphite nanoplatelets/epoxy nanocomposites were prepared and studied varying the filler content. Morphological characteristics were examined via scanning electron microscopy, while structural changes occurring in barium titanate as a function of temperature were investigated by means of X-ray diffraction. Broadband dielectric spectroscopy was employed for determining the dielectric response of the prepared systems. Based on the conducted analysis it was found that three relaxation processes are present in the spectra of the examined materials. From the slower to the faster one, these are interfacial polarization, glass to rubber transition of the polymer matrix, and rearrangement of polar side groups of the polymer chain. Systems' functionality and energy storing efficiency were assessed in terms of dielectric reinforcing function. Finally, the energy density of all systems was evaluated. Composite systems with embedded graphite nanoplatelets exhibit higher energy storing efficiency, while thermally induced structural changes in ferroelectric particles provide functional behavior to barium titanate composites. -- Graphical abstract: Systems' functionality, electrical relaxations and energy storing efficiency were assessed in terms of dielectric permittivity, electric modulus and dielectric reinforcing function (G). Further, the energy density (U) of all systems was evaluated. Composite systems with embedded graphite nanoplatelets exhibit higher energy storing efficiency, while thermally induced structural changes in ferroelectric particles provide functional behavior to barium titanate composites. Highlights: ► Relaxation phenomena were found to be present in all studied systems. ► Two processes emanate from the polymer matrix (α-mode and β-mode). ► Systems' electrical heterogeneity gives rise to interfacial polarization. ► BaTiO 3 /epoxy composites exhibit functional behavior due to structural changes. ► x
Level densities of iron isotopes and lower-energy enhancement of y-strength function
International Nuclear Information System (INIS)
Voinov, A V; Grimes, S M; Agvaanluvsan, U; Algin, E; Belgya, T; Brune, C R; Guttormsen, M; Hornish, M J; Massey, T N; Mitchell, G; Rekstad, J; Schiller, A; Siem, S
2005-01-01
The neutron spectrum from the 55 Mn(d,n) 56 Fe reaction has been measured at E d = 7 MeV. The level density of 56 Fe obtained from neutron evaporation spectrum has been compared to the level density from Oslo-type 57 Fe( 3 He, aγ) 56 Fe experiment [1]. The good agreement supports the recent results [1, 8] including an availability of a low-energy enhancement in the γ-strength function for iron isotopes. The new level density function allowed us to investigate an excitation energy dependence of this enhancement, which is shown to increase with increasing excitation energy
Energy Technology Data Exchange (ETDEWEB)
O' Neill, C.; Waskoenig, J. [Centre for Plasma Physics, School of Maths and Physics, Queen' s University Belfast, Belfast BT7 1NN (United Kingdom); Gans, T. [Centre for Plasma Physics, School of Maths and Physics, Queen' s University Belfast, Belfast BT7 1NN (United Kingdom); York Plasma Institute, Department of Physics, University of York, York YO10 5DD (United Kingdom)
2012-10-08
A multi-scale numerical model based on hydrodynamic equations with semi-kinetic treatment of electrons is used to investigate the influence of dual frequency excitation on the effective electron energy distribution function (EEDF) in a radio-frequency driven atmospheric pressure plasma. It is found that variations of power density, voltage ratio, and phase relationship provide separate control over the electron density and the mean electron energy. This is exploited to directly influence both the phase dependent and time averaged effective EEDF. This enables tailoring the EEDF for enhanced control of non-equilibrium plasma chemical kinetics at ambient pressure and temperature.
DEFF Research Database (Denmark)
Fromager, Emmanuel; Jensen, Hans Jørgen Aagaard
2011-01-01
Range-separated density-functional theory combines wave function theory for the long-range part of the two-electron interaction with density-functional theory for the short-range part. When describing the long-range interaction with non-variational methods, such as perturbation or coupled......-cluster theories, self-consistency effects are introduced in the density functional part, which for an exact solution requires iterations. They are generally assumed to be small but no detailed study has been performed so far. Here, the authors analyze self-consistency when using Møller-Plesset-type (MP......) perturbation theory for the long range interaction. The lowest-order self-consistency corrections to the wave function and the energy, that enter the perturbation expansions at the second and fourth order, respectively, are both expressed in terms of the one-electron reduced density matrix. The computational...
International Nuclear Information System (INIS)
Zhou, Junle; Chen, Lingen; Ding, Zemin; Sun, Fengrui
2016-01-01
Ecological performance of a single resonance ESE heat engine with heat leakage is conducted by applying finite time thermodynamics. By introducing Nielsen function and numerical calculations, expressions about power output, efficiency, entropy generation rate and ecological objective function are derived; relationships between ecological objective function and power output, between ecological objective function and efficiency as well as between power output and efficiency are demonstrated; influences of system parameters of heat leakage, boundary energy and resonance width on the optimal performances are investigated in detail; a specific range of boundary energy is given as a compromise to make ESE heat engine system work at optimal operation regions. Comparing performance characteristics with different optimization objective functions, the significance of selecting ecological objective function as the design objective is clarified specifically: when changing the design objective from maximum power output into maximum ecological objective function, the improvement of efficiency is 4.56%, while the power output drop is only 2.68%; when changing the design objective from maximum efficiency to maximum ecological objective function, the improvement of power output is 229.13%, and the efficiency drop is only 13.53%. - Highlights: • An irreversible single resonance energy selective electron heat engine is studied. • Heat leakage between two reservoirs is considered. • Power output, efficiency and ecological objective function are derived. • Optimal performance comparison for three objective functions is carried out.
Generalized Riemann zeta-function regularization and Casimir energy for a piecewise uniform string
International Nuclear Information System (INIS)
Li Xinzhou; Shi Xin; Zhang Jianzu.
1990-12-01
The generalized zeta-function techniques will be utilized to investigate the Casimir energy for the transverse oscillations of a piecewise uniform closed string. We find that zeta-function regularization method can lead straightforwardly to a correct result. (author). 6 refs
Tigabu, A.D.; Berkhout, F.G.H.; van Beukering, P.J.H.
2015-01-01
This paper compares the historical development of innovation systems related to biogas and improved cooking stove technologies in Rwanda and Kenya by applying the 'functions approach'. It argues that the accumulation of functions in these four renewable energy technological innovation systems (TISs)
Tao, Jianmin; Ye, Lin-Hui; Duan, Yuhua
2017-12-01
The primary goal of Kohn-Sham density functional theory is to evaluate the exchange-correlation contribution to electronic properties. However, the accuracy of a density functional can be affected by the electron density. Here we apply the nonempirical Tao-Mo (TM) semilocal functional to study the influence of the electron density on the exchange and correlation energies of atoms and ions, and compare the results with the commonly used nonempirical semilocal functionals local spin-density approximation (LSDA), Perdew-Burke-Ernzerhof (PBE), Tao-Perdew-Staroverov-Scuseria (TPSS), and hybrid functional PBE0. We find that the spin-restricted Hartree-Fock density yields the exchange and correlation energies in good agreement with the Optimized Effective Potential method, particularly for spherical atoms and ions. However, the errors of these semilocal and hybrid functionals become larger for self-consistent densities. We further find that the quality of the electron density have greater effect on the exchange-correlation energies of kinetic energy density-dependent meta-GGA functionals TPSS and TM than on those of the LSDA and GGA, and therefore, should have greater influence on the performance of meta-GGA functionals. Finally, we show that the influence of the density quality on PBE0 is slightly reduced, compared to that of PBE, due to the exact mixing.
Yu, Min; Doak, Peter; Tamblyn, Isaac; Neaton, Jeffrey B
2013-05-16
Functional hybrid interfaces between organic molecules and semiconductors are central to many emerging information and solar energy conversion technologies. Here we demonstrate a general, empirical parameter-free approach for computing and understanding frontier orbital energies - or redox levels - of a broad class of covalently bonded organic-semiconductor surfaces. We develop this framework in the context of specific density functional theory (DFT) and many-body perturbation theory calculations, within the GW approximation, of an exemplar interface, thiophene-functionalized silicon (111). Through detailed calculations taking into account structural and binding energetics of mixed-monolayers consisting of both covalently attached thiophene and hydrogen, chlorine, methyl, and other passivating groups, we quantify the impact of coverage, nonlocal polarization, and interface dipole effects on the alignment of the thiophene frontier orbital energies with the silicon band edges. For thiophene adsorbate frontier orbital energies, we observe significant corrections to standard DFT (∼1 eV), including large nonlocal electrostatic polarization effects (∼1.6 eV). Importantly, both results can be rationalized from knowledge of the electronic structure of the isolated thiophene molecule and silicon substrate systems. Silicon band edge energies are predicted to vary by more than 2.5 eV, while molecular orbital energies stay similar, with the different functional groups studied, suggesting the prospect of tuning energy alignment over a wide range for photoelectrochemistry and other applications.
Multiple parton scattering in nuclei: heavy quark energy loss and modified fragmentation functions
International Nuclear Information System (INIS)
Zhang Benwei; Wang, Enke; Wang Xinnian
2005-01-01
Multiple scattering, induced radiative energy loss and modified fragmentation functions of a heavy quark in nuclear matter are studied within the framework of generalized factorization in perturbative QCD. Modified heavy quark fragmentation functions and energy loss are derived in detail with illustration of the mass dependencies of the Landau-Pomeranchuk-Migdal interference effects and heavy quark energy loss. Due to the quark mass dependence of the gluon formation time, the nuclear size dependencies of nuclear modification of the heavy quark fragmentation function and heavy quark energy loss are found to change from a linear to a quadratic form when the initial energy and momentum scale are increased relative to the quark mass. The radiative energy loss of the heavy quark is also significantly suppressed due to limited cone of gluon radiation imposed by the mass. Medium modification of the heavy quark fragmentation functions is found to be limited to the large z region due to the form of heavy quark fragmentation functions in vacuum
International Nuclear Information System (INIS)
Sotiropoulou, P; Koukou, V; Martini, N; Nikiforidis, G; Michail, C; Kandarakis, I; Fountos, G; Kounadi, E
2015-01-01
In this study an analytical approximation of dual-energy inverse functions is presented for the estimation of the calcium-to-phosphorous (Ca/P) mass ratio, which is a crucial parameter in bone health. Bone quality could be examined by the X-ray dual-energy method (XDEM), in terms of bone tissue material properties. Low- and high-energy, log- intensity measurements were combined by using a nonlinear function, to cancel out the soft tissue structures and generate the dual energy bone Ca/P mass ratio. The dual-energy simulated data were obtained using variable Ca and PO 4 thicknesses on a fixed total tissue thickness. The XDEM simulations were based on a bone phantom. Inverse fitting functions with least-squares estimation were used to obtain the fitting coefficients and to calculate the thickness of each material. The examined inverse mapping functions were linear, quadratic, and cubic. For every thickness, the nonlinear quadratic function provided the optimal fitting accuracy while requiring relative few terms. The dual-energy method, simulated in this work could be used to quantify bone Ca/P mass ratio with photon-counting detectors. (paper)
Correlation Functions of the Energy Momentum Tensor on Spaces of Constant Curvature
Osborn, H
2000-01-01
An analysis of one and two point functions of the energy momentum tensor on homogeneous spaces of constant curvature is undertaken. The possibility of proving a c-theorem in this framework is discussed, in particular in relation to the coefficients c,a, which appear in the energy momentum tensor trace on general curved backgrounds in four dimensions. Ward identities relating the correlation functions are derived and explicit expressions are obtained for free scalar, spinor field theories in general dimensions and also free vector fields in dimension four. A natural geometric formalism which is independent of any choice of coordinates is used and the role of conformal symmetries on such constant curvature spaces is analysed. The results are shown to be constrained by the operator product expansion. For negative curvature the spectral representation, involving unitary positive energy representations of $O(d-1,2)$, for two point functions of vector currents is derived in detail and extended to the energy momentu...
Choi, Yun Seok
2017-05-26
Full waveform inversion (FWI) using an energy-based objective function has the potential to provide long wavelength model information even without low frequency in the data. However, without the back-propagation method (adjoint-state method), its implementation is impractical for the model size of general seismic survey. We derive the gradient of the energy-based objective function using the back-propagation method to make its FWI feasible. We also raise the energy signal to the power of a small positive number to properly handle the energy signal imbalance as a function of offset. Examples demonstrate that the proposed FWI algorithm provides a convergent long wavelength structure model even without low-frequency information, which can be used as a good starting model for the subsequent conventional FWI.
Casimir energies in M4≥/sup N/ for even N. Green's-function and zeta-function techniques
International Nuclear Information System (INIS)
Kantowski, R.; Milton, K.A.
1987-01-01
The Green's-function technique developed in the first paper in this series is generalized to apply to massive scalar, vector, second-order tensor, and Dirac spinor fields, as a preliminary to a full graviton calculation. The Casimir energies are of the form u/sub Casimir/ = (1/a 4 )[α/sub N/lna/b)+β/sub N/], where N (even) is the dimension of the internal sphere, a is its radius, and b/sup -1/ is an ultraviolet cutoff (presumably at the Planck scale). The coefficient of the divergent logarithm, α/sub N/, is unambiguously obtained for each field considered. The Green's-function technique gives rise to no difficulties in the evaluation of imaginary-mass-mode contributions to the Casimir energy. In addition, a new, simplified zeta-function technique is presented which is very easily implemented by symbolic programs, and which, of course, gives the same results. An error in a previous zeta-function calculation of the Casimir energy for even N is pointed out
Correlation functions of the energy-momentum tensor in SU(2) gauge theory at finite temperature
DEFF Research Database (Denmark)
Huebner, K.; Karsch, F.; Pica, Claudio
2008-01-01
We calculate correlation functions of the energy-momentum tensor in the vicinity of the deconfinement phase transition of (3+1)-dimensional SU(2) gauge theory and discuss their critical behavior in the vicinity of the second order deconfinement transition. We show that correlation functions...... of the trace of the energy momentum tensor diverge uniformly at the critical point in proportion to the specific heat singularity. Correlation functions of the pressure, on the other hand, stay finite at the critical point. We discuss the consequences of these findings for the analysis of transport...... coefficients, in particular the bulk viscosity, in the vicinity of a second order phase transition point....
Replacing leads by self-energies using non-equilibrium Green's functions
International Nuclear Information System (INIS)
Michael, Fredrick; Johnson, M.D.
2003-01-01
Open quantum systems consist of semi-infinite leads which transport electrons to and from the device of interest. We show here that within the non-equilibrium Green's function technique for continuum systems, the leads can be replaced by simple c-number self-energies. Our starting point is an approach for continuum systems developed by Feuchtwang. The reformulation developed here is simpler to understand and carry out than the somewhat unwieldly manipulations typical in the Feuchtwang method. The self-energies turn out to have a limited variability: the retarded self-energy Σ r depends on the arbitrary choice of internal boundary conditions, but the non-equilibrium self-energy or scattering function Σ which determines transport is invariant for a broad class of boundary conditions. Expressed in terms of these self-energies, continuum non-equilibrium transport calculations take a particularly simple form similar to that developed for discrete systems
Oferkin, Igor V; Katkova, Ekaterina V; Sulimov, Alexey V; Kutov, Danil C; Sobolev, Sergey I; Voevodin, Vladimir V; Sulimov, Vladimir B
2015-01-01
The adequate choice of the docking target function impacts the accuracy of the ligand positioning as well as the accuracy of the protein-ligand binding energy calculation. To evaluate a docking target function we compared positions of its minima with the experimentally known pose of the ligand in the protein active site. We evaluated five docking target functions based on either the MMFF94 force field or the PM7 quantum-chemical method with or without implicit solvent models: PCM, COSMO, and SGB. Each function was tested on the same set of 16 protein-ligand complexes. For exhaustive low-energy minima search the novel MPI parallelized docking program FLM and large supercomputer resources were used. Protein-ligand binding energies calculated using low-energy minima were compared with experimental values. It was demonstrated that the docking target function on the base of the MMFF94 force field in vacuo can be used for discovery of native or near native ligand positions by finding the low-energy local minima spectrum of the target function. The importance of solute-solvent interaction for the correct ligand positioning is demonstrated. It is shown that docking accuracy can be improved by replacement of the MMFF94 force field by the new semiempirical quantum-chemical PM7 method.
Directory of Open Access Journals (Sweden)
Igor V. Oferkin
2015-01-01
Full Text Available The adequate choice of the docking target function impacts the accuracy of the ligand positioning as well as the accuracy of the protein-ligand binding energy calculation. To evaluate a docking target function we compared positions of its minima with the experimentally known pose of the ligand in the protein active site. We evaluated five docking target functions based on either the MMFF94 force field or the PM7 quantum-chemical method with or without implicit solvent models: PCM, COSMO, and SGB. Each function was tested on the same set of 16 protein-ligand complexes. For exhaustive low-energy minima search the novel MPI parallelized docking program FLM and large supercomputer resources were used. Protein-ligand binding energies calculated using low-energy minima were compared with experimental values. It was demonstrated that the docking target function on the base of the MMFF94 force field in vacuo can be used for discovery of native or near native ligand positions by finding the low-energy local minima spectrum of the target function. The importance of solute-solvent interaction for the correct ligand positioning is demonstrated. It is shown that docking accuracy can be improved by replacement of the MMFF94 force field by the new semiempirical quantum-chemical PM7 method.
International Nuclear Information System (INIS)
Arslanbekov, R.R.; Kolokolov, N.B.; Kudryavtsev, A.A.; Khromov, N.A.
1991-01-01
Gorbunov et al. have developed a kinetic theory of the electron current drawn by a probe, which substantially extends the region of applicability of the probe method for determining the electron energy distribution function, enabling probes to be used for intermediate and high pressures (up to p ≤ 0.5 atm for monatomic gases). They showed that for λ var-epsilon >> a + d (where a is the probe radius, d is the sheath thickness, and λ var-epsilon is the electron energy relaxation length) the current density j e (V) drawn by the probe is related to the unperturbed distribution function by an integral equation involving the distribution function. The kernal of the integral equation can be written as a function of the diffusion parameter. In the present paper the method of quadrature sums is employed in order to obtain the electron energy distribution function from probe characteristics at intermediate and high pressures. This technique enables them to recover the distribution function from the integral equation when the diffusion parameter has an arbitrary energy dependence ψ 0 (var-epsilon) in any given energy range. The effectiveness of the method is demonstrated by application to both model problems and experimental data
An Energy-Based Limit State Function for Estimation of Structural Reliability in Shock Environments
Directory of Open Access Journals (Sweden)
Michael A. Guthrie
2013-01-01
Full Text Available limit state function is developed for the estimation of structural reliability in shock environments. This limit state function uses peak modal strain energies to characterize environmental severity and modal strain energies at failure to characterize the structural capacity. The Hasofer-Lind reliability index is briefly reviewed and its computation for the energy-based limit state function is discussed. Applications to two degree of freedom mass-spring systems and to a simple finite element model are considered. For these examples, computation of the reliability index requires little effort beyond a modal analysis, but still accounts for relevant uncertainties in both the structure and environment. For both examples, the reliability index is observed to agree well with the results of Monte Carlo analysis. In situations where fast, qualitative comparison of several candidate designs is required, the reliability index based on the proposed limit state function provides an attractive metric which can be used to compare and control reliability.
The effect of work function changes on secondary ion energy spectra
International Nuclear Information System (INIS)
Wittmaack, K.
1983-01-01
The effect of work function changes on experimental secondary ion energy spectra is discussed. In agreement with theory the measured ion intensities frequently exhibit an exponential work function dependence. However, the predicted velocity dependence is only observed at fairly high secondary ion energies. In the absence of a velocity dependence of the degree of ionization measured shifts of energy spectra reflect work function changes directly. Various instrumental problems are shown to aggravate a detailed comparison between experiment and theory. Significant artefacts must be expected if the extraction field is of the order of or less than the lateral field induced by a work function difference between the bombarded spot and the surrounding sample surface. (Auth.)
Energy Technology Data Exchange (ETDEWEB)
Greenblatt, J.; Letschert, V. [Environmental Energy Technologies Division, Lawrence Berkeley National Laboratory, Berkeley, CA (United States); Hopkins, A. [Vermont Department of Public Service, Burlington, VT (United States); Blasnik, M. [Blasnik Consulting, Boston, MA (United States)
2013-02-15
Field-metered energy use data for 1,467 refrigerators and 185 freezers from seven studies conducted between 1992 and 2010 were used to calculate usage adjustment factors (UAFs), defined as the ratio of measured to tested annual energy use. Multiple regressions of UAFs against several household and climate variables were then performed to obtain separate predictive functions for primary (most-used) refrigerators, secondary (second most-used) refrigerators, and freezers, and residual differences between observed and modeled UAFs were fit to log normal distributions. These UAF functions were used to project energy use in the more than 4,000 households in the 2005 Residential Energy Consumption Survey, a statistical representation of US homes. These energy use projections formed the basis of calculating lifecycle energy savings for more efficient refrigerators and freezers, as well as national energy and cost savings. Results were compared with previous published work by the Department of Energy, demonstrating how UAFs impact energy and cost savings. Such an approach could be further improved with additional data and adapted for other appliances in future analyses.
Degenerate RS perturbation theory. [Rayleigh-Schroedinger energies and wave functions
Hirschfelder, J. O.; Certain, P. R.
1974-01-01
A concise, systematic procedure is given for determining the Rayleigh-Schroedinger energies and wave functions of degenerate states to arbitrarily high orders even when the degeneracies of the various states are resolved in arbitrary orders. The procedure is expressed in terms of an iterative cycle in which the energy through the (2n + 1)-th order is expressed in terms of the partially determined wave function through the n-th order. Both a direct and an operator derivation are given. The two approaches are equivalent and can be transcribed into each other. The direct approach deals with the wave functions (without the use of formal operators) and has the advantage that it resembles the usual treatment of nondegenerate perturbations and maintains close contact with the basic physics. In the operator approach, the wave functions are expressed in terms of infinite-order operators which are determined by the successive resolution of the space of the zeroth-order functions.
Stefanucci, G.; Pavlyukh, Y.; Uimonen, A.-M.; van Leeuwen, R.
2014-09-01
We present a diagrammatic approach to construct self-energy approximations within many-body perturbation theory with positive spectral properties. The method cures the problem of negative spectral functions which arises from a straightforward inclusion of vertex diagrams beyond the GW approximation. Our approach consists of a two-step procedure: We first express the approximate many-body self-energy as a product of half-diagrams and then identify the minimal number of half-diagrams to add in order to form a perfect square. The resulting self-energy is an unconventional sum of self-energy diagrams in which the internal lines of half a diagram are time-ordered Green's functions, whereas those of the other half are anti-time-ordered Green's functions, and the lines joining the two halves are either lesser or greater Green's functions. The theory is developed using noninteracting Green's functions and subsequently extended to self-consistent Green's functions. Issues related to the conserving properties of diagrammatic approximations with positive spectral functions are also addressed. As a major application of the formalism we derive the minimal set of additional diagrams to make positive the spectral function of the GW approximation with lowest-order vertex corrections and screened interactions. The method is then applied to vertex corrections in the three-dimensional homogeneous electron gas by using a combination of analytical frequency integrations and numerical Monte Carlo momentum integrations to evaluate the diagrams.
International Nuclear Information System (INIS)
Sergeev, Alexey; Jovanovic, Raka; Kais, Sabre; Alharbi, Fahhad H
2016-01-01
We consider the density of a fermionic system as a functional of the potential, in one-dimensional case, where it is approximated by the Thomas–Fermi term plus semiclassical corrections through the gradient expansion. We compare this asymptotic series with the exact answer for the case of the harmonic oscillator and the Morse potential. It is found that the leading (Thomas–Fermi) term is in agreement with the exact density, but the subdominant term does not agree in terms of the asymptotic behavior because of the presence of oscillations in the exact density, but their absence in the gradient expansion. However, after regularization of the density by convolution with a Gaussian, the agreement can be established even in the subdominant term. Moreover, it is found that the expansion is always divergent, and its terms grow proportionally to the factorial function of the order, similar to the well-known divergence of perturbation series in field theory and the quantum anharmonic oscillator. Padé–Hermite approximants allow summation of the series, and one of the branches of the approximants agrees with the density. (paper)
Hypothalamus-pituitary-thyroid axis activity and function of cardiac muscle in energy deficit
Directory of Open Access Journals (Sweden)
Katarzyna Lachowicz
2017-12-01
Full Text Available Frequently repeated statement that energy restriction is a factor that improves cardiovascular system function seems to be not fully truth. Low energy intake modifies the hypothalamus-pituitary-thyroid axis activity and thyroid hormone peripheral metabolism. Thyroid hormones, as modulators of the expression and activity of many cardiomyocyte proteins, control heart function. Decreased thyroid hormone levels and their disturbanced conversion and action result in alternation of cardiac remodeling, disorder of calcium homeostasis and diminish myocardial contractility. This review provides a summary of the current state of knowledge about the mechanisms of energy restriction effects on thyroidal axis activity, thyroid hormone peripheral metabolism and action in target tissues, especially in cardiac myocytes. We also showed the existence of energy restriction-thyroid-heart pathway.
Low-energy ion distribution functions on a magnetically quiet day at geostationary altitude /L = 7/
Singh, N.; Raitt, W. J.; Yasuhara, F.
1982-01-01
Ion energy and pitch angle distribution functions are examined for a magnetically quiet day using averaged data from ATS 6. For both field-aligned and perpendicular fluxes, the populations have a mixture of characteristic energies, and the distribution functions can be fairly well approximated by Maxwellian distributions over three different energy bands in the range 3-600 eV. Pitch angle distributions varying with local time, and energy distributions are used to compute total ion density. Pitch angle scattering mechanisms responsible for the observed transformation of pitch angle distribution are examined, and it is found that a magnetic noise of a certain power spectral density belonging to the electromagnetic ion cyclotron mode near the ion cyclotron frequency can be effective in trapping the field aligned fluxes by pitch angle scattering.
Structure and potential energy function investigation on UH and UH2 molecules
International Nuclear Information System (INIS)
Luo Deli; Liu Xiaoya; Jiang Gang; Meng Daqiao; Zhu Zhenghe
2001-01-01
Density functional (B3LYP) method with Relativistic Effective Core Potential (RECP) have been used to optimize the structures and to calculate the potential energy function both for the ground and excited states of UH and UH 2 molecules. Results show that the ground state of UH and UH 2 molecules are X 4 II and X 3 A 2 , which belongs to C2v symmetry, and the disassociation energies are 2.886 eV and 5.249 ev respectively, and the spectral data of UH and UH 2 have also been derived both for the ground and excited state. The potential energy function of UH and UH 2 have been derived based on normal equation fitting method and the many-body expansion theory. The information is useful to mechanism analysis of the aging effect of the hydrogen storage material
Energy level alignment and quantum conductance of functionalized metal-molecule junctions
DEFF Research Database (Denmark)
Jin, Chengjun; Strange, Mikkel; Markussen, Troels
2013-01-01
We study the effect of functional groups (CH3*4, OCH3, CH3, Cl, CN, F*4) on the electronic transport properties of 1,4-benzenediamine molecular junctions using the non-equilibrium Green function method. Exchange and correlation effects are included at various levels of theory, namely density...... functional theory (DFT), energy level-corrected DFT (DFT+Σ), Hartree-Fock and the many-body GW approximation. All methods reproduce the expected trends for the energy of the frontier orbitals according to the electron donating or withdrawing character of the substituent group. However, only the GW method...... predicts the correct ordering of the conductance amongst the molecules. The absolute GW (DFT) conductance is within a factor of two (three) of the experimental values. Correcting the DFT orbital energies by a simple physically motivated scissors operator, Σ, can bring the DFT conductances close...
International Nuclear Information System (INIS)
Vagner, S.D.; Ignat'ev, B.K.
1983-01-01
Electron energy distribution functions (EEDF) are recorded in an rf discharge in a mixture of neon and argon. The rates of different ionization processes and the energy losses of the electrons in the bulk of the discharge are calculated. The experimentally recorded electron energy distribution functions are compared with distributions calculated using a nonlocal theory. The effect of an rf voltage in the probe circuit on the recorded electron energy distribution functions is investigated experimentally
Systematic studies of binding energy dependence of neutron-proton momentum correlation function
International Nuclear Information System (INIS)
Wei, Y B; Ma, Y G; Shen, W Q; Ma, G L; Wang, K; Cai, X Z; Zhong, C; Guo, W; Chen, J G; Fang, D Q; Tian, W D; Zhou, X F
2004-01-01
Hanbury Brown-Twiss (HBT) results of the neutron-proton correlation function have been systematically investigated for a series of nuclear reactions with light projectiles with the help of the isospin-dependent quantum molecular dynamics model. The relationship between the binding energy per nucleon of the projectiles and the strength of the neutron-proton HBT at small relative momentum has been obtained. Results show that neutron-proton HBT results are sensitive to the binding energy per nucleon
Energy Technology Data Exchange (ETDEWEB)
Amusia, M.Ya. [The Racah Institute of Physics, Hebrew University, 91904 Jerusalem (Israel); A F Ioffe Physical-Technical Institute, 194921 St Petersburg (Russian Federation); Mikhailov, A.I.; Mikhailov, I.A. [St Petersburg Nuclear Physics Institute, Gatchina, 188350 St Petersburg (Russian Federation)
1999-10-28
Double ionization and ionization with excitation of helium-like ions with Z>>1 from 2 {sup 1}S and 2 {sup 3}S states on the absorption of a high-frequency photon have been considered. The analytical calculation is performed in the non-relativistic photon energy range in the lowest order of perturbation theory in the inter-electron interaction. Coulomb wavefunctions and the Coulomb Green function are used as a zeroth-order approximation. Differential and total cross sections of the processes are expressed via the corresponding values for the single photoionization. The photoelectron energy spectrum is obtained in the marginal energy range (i.e. for p{sub 1}>>p{sub 2}, p{sub 1} and p{sub 2} momenta of photoelectrons) for the double-ionization process. Simple relations between the cross sections of double ionization and ionization with excitation are derived. (author)
International Nuclear Information System (INIS)
Tait, E W; Payne, M C; Ratcliff, L E; Haynes, P D; Hine, N D M
2016-01-01
Experimental techniques for electron energy loss spectroscopy (EELS) combine high energy resolution with high spatial resolution. They are therefore powerful tools for investigating the local electronic structure of complex systems such as nanostructures, interfaces and even individual defects. Interpretation of experimental electron energy loss spectra is often challenging and can require theoretical modelling of candidate structures, which themselves may be large and complex, beyond the capabilities of traditional cubic-scaling density functional theory. In this work, we present functionality to compute electron energy loss spectra within the onetep linear-scaling density functional theory code. We first demonstrate that simulated spectra agree with those computed using conventional plane wave pseudopotential methods to a high degree of precision. The ability of onetep to tackle large problems is then exploited to investigate convergence of spectra with respect to supercell size. Finally, we apply the novel functionality to a study of the electron energy loss spectra of defects on the (1 0 1) surface of an anatase slab and determine concentrations of defects which might be experimentally detectable. (paper)
A method for ion distribution function evaluation using escaping neutral atom kinetic energy samples
International Nuclear Information System (INIS)
Goncharov, P.R.; Ozaki, T.; Veshchev, E.A.; Sudo, S.
2008-01-01
A reliable method to evaluate the probability density function for escaping atom kinetic energies is required for the analysis of neutral particle diagnostic data used to study the fast ion distribution function in fusion plasmas. Digital processing of solid state detector signals is proposed in this paper as an improvement of the simple histogram approach. Probability density function for kinetic energies of neutral particles escaping from the plasma has been derived in a general form taking into account the plasma ion energy distribution, electron capture and loss rates, superposition along the diagnostic sight line and the magnetic surface geometry. A pseudorandom number generator has been realized that enables a sample of escaping neutral particle energies to be simulated for given plasma parameters and experimental conditions. Empirical probability density estimation code has been developed and tested to reconstruct the probability density function from simulated samples assuming. Maxwellian and classical slowing down plasma ion energy distribution shapes for different temperatures and different slowing down times. The application of the developed probability density estimation code to the analysis of experimental data obtained by the novel Angular-Resolved Multi-Sightline Neutral Particle Analyzer has been studied to obtain the suprathermal particle distributions. The optimum bandwidth parameter selection algorithm has also been realized. (author)
International Nuclear Information System (INIS)
Cui, L.; Forero Rueda, M.A.; Gilchrist, M.D.
2009-01-01
The energy absorbing liner of safety helmets was optimised using finite element modelling. In this present paper, a functionally graded foam (FGF) liner was modelled, while keeping the average liner density the same as in a corresponding reference single uniform density liner model. Use of a functionally graded foam liner would eliminate issues regarding delamination and crack propagation between interfaces of different density layers which could arise in liners with discrete density variations. As in our companion Part I paper [Forero Rueda MA, Cui L, Gilchrist MD. Optimisation of energy absorbing liner for equestrian helmets. Part I: Layered foam liner. Mater Des [submitted for publication
Correlation functions of the energy-momentum tensor on spaces of constant curvature
International Nuclear Information System (INIS)
Osborn, H.; Shore, G.M.
2000-01-01
An analysis of one- and two-point functions of the energy-momentum tensor on homogeneous spaces of constant curvature is undertaken. The possibility of proving a c-theorem in this framework is discussed, in particular in relation to the coefficients c,a, which appear in the energy-momentum tensor trace on general curved backgrounds in four dimensions. Ward identities relating the correlation functions are derived and explicit expressions are obtained for free scalar, spinor field theories in general dimensions and also free vector fields in dimension four. A natural geometric formalism which is independent of any choice of coordinates is used and the role of conformal symmetries on such constant curvature spaces is analysed. The results are shown to be constrained by the operator product expansion. For negative curvature the spectral representation, involving unitary positive energy representations of O(d-1,2), for two-point functions of vector currents is derived in detail and extended to the energy-momentum tensor by analogy. It is demonstrated that, at non-coincident points, the two-point functions are not related to a in any direct fashion and there is no straightforward demonstration obtainable in this framework of irreversibility under renormalisation group flow of any function of the couplings for four-dimensional field theories which reduces to a at fixed points
The cascade probabilistic functions with taking into account energy losses for ions. Chapter 3
International Nuclear Information System (INIS)
2003-01-01
In the Chapter 3 the cascade probabilistic functions mathematical simulation with taking into account energy losses for ions are considered. The calculation of the CPF on the computer is carried out. The influence of both the interaction number and the penetration depth on the CPF determination field for ions are revealed. The estimation of energy losses contribution in the simplest CPF is made. Calculation algorithm for radiation defects concentration at ion irradiation with use of the CPF with taking into account of energy losses is given
Accurate Energies and Structures for Large Water Clusters Using the X3LYP Hybrid Density Functional
Su, Julius T.; Xu, Xin; Goddard, William A., III
2004-01-01
We predict structures and energies of water clusters containing up to 19 waters with X3LYP, an extended hybrid density functional designed to describe noncovalently bound systems as accurately as covalent systems. Our work establishes X3LYP as the most practical ab initio method today for calculating accurate water cluster structures and energies. We compare X3LYP/aug-cc-pVTZ energies to the most accurate theoretical values available (n = 2−6, 8), MP2 with basis set superposition error (BSSE)...
Complex-energy approach to sum rules within nuclear density functional theory
Hinohara, Nobuo; Kortelainen, Markus; Nazarewicz, Witold; Olsen, Erik
2015-04-01
Background: The linear response of the nucleus to an external field contains unique information about the effective interaction, the correlations governing the behavior of the many-body system, and the properties of its excited states. To characterize the response, it is useful to use its energy-weighted moments, or sum rules. By comparing computed sum rules with experimental values, the information content of the response can be utilized in the optimization process of the nuclear Hamiltonian or the nuclear energy density functional (EDF). But the additional information comes at a price: compared to the ground state, computation of excited states is more demanding. Purpose: To establish an efficient framework to compute energy-weighted sum rules of the response that is adaptable to the optimization of the nuclear EDF and large-scale surveys of collective strength, we have developed a new technique within the complex-energy finite-amplitude method (FAM) based on the quasiparticle random-phase approximation (QRPA). Methods: To compute sum rules, we carry out contour integration of the response function in the complex-energy plane. We benchmark our results against the conventional matrix formulation of the QRPA theory, the Thouless theorem for the energy-weighted sum rule, and the dielectric theorem for the inverse-energy-weighted sum rule. Results: We derive the sum-rule expressions from the contour integration of the complex-energy FAM. We demonstrate that calculated sum-rule values agree with those obtained from the matrix formulation of the QRPA. We also discuss the applicability of both the Thouless theorem about the energy-weighted sum rule and the dielectric theorem for the inverse-energy-weighted sum rule to nuclear density functional theory in cases when the EDF is not based on a Hamiltonian. Conclusions: The proposed sum-rule technique based on the complex-energy FAM is a tool of choice when optimizing effective interactions or energy functionals. The method
Research on energy-saving effect of technological progress based on Cobb-Douglas production function
International Nuclear Information System (INIS)
Yuan Chaoqing; Liu Sifeng; Wu Junlong
2009-01-01
Energy issues receive more and more attention these days. And it is considered that technological progress is an essential approach to save energy. This essay is to analyze the relation between energy intensity and technological progress by Cobb-Douglas production function in which energy, labor, capital and technological progress are taken as independent variables. It proves that the growth of output per capital and output per labor will increase energy intensity while technological progress will decrease energy intensity. Empirical research on Chinese industry is used here to indicate technological progress greatly decreases energy intensity. Because of the interferences of Asian financial crisis, there is something abnormal in the data. So in the empirical research, average weaken buffer operator (ABWO) is applied to weaken the interference of Asian financial crisis to the fixed assets, energy and value added. The results of the empirical research show that technological progress decreases energy intensity of Chinese industry an average of 6.3% every year in China.
Edge corrections to electromagnetic Casimir energies from general-purpose Mathieu-function routines
Blose, Elizabeth Noelle; Ghimire, Biswash; Graham, Noah; Stratton-Smith, Jeremy
2015-01-01
Scattering theory methods make it possible to calculate the Casimir energy of a perfectly conducting elliptic cylinder opposite a perfectly conducting plane in terms of Mathieu functions. In the limit of zero radius, the elliptic cylinder becomes a finite-width strip, which allows for the study of edge effects. However, existing packages for computing Mathieu functions are insufficient for this calculation because none can compute Mathieu functions of both the first and second kind for complex arguments. To address this shortcoming, we have written a general-purpose Mathieu-function package, based on algorithms developed by Alhargan. We use these routines to find edge corrections to the proximity force approximation for the Casimir energy of a perfectly conducting strip opposite a perfectly conducting plane.
Model etch profiles for ion energy distribution functions in an inductively coupled plasma reactor
International Nuclear Information System (INIS)
Chen, W.; Abraham-Shrauner, B.; Woodworth, J.R.
1999-01-01
Rectangular trench profiles are modeled with analytic etch rates determined from measured ion distribution functions. The pattern transfer step for this plasma etch is for trilayer lithography. Argon and chlorine angular ion energy distribution functions measured by a spherical collector ring analyzer are fit to a sum of drifting Maxwellian velocity distribution functions with anisotropic temperatures. The fit of the model ion distribution functions by a simulated annealing optimization procedure converges adequately for only two drifting Maxwellians. The etch rates are proportional to analytic expressions for the ion energy flux. Numerical computation of the etch profiles by integration of the characteristic equations for profile points and connection of the profiles points is efficient. copyright 1999 American Vacuum Society
The EDDA experiment: proton-proton elastic scattering excitation functions at intermediate energies
International Nuclear Information System (INIS)
Hinterberher, F.
1996-01-01
The EDDA experiment is designed to provide a high precision measurement of proton-proton elastic scattering excitation functions ranging from 0.5 to 2.5 GeV of (lab) incident kinetic energy. It is an internal target experiment utilizing the proton beam of the cooler synchrotron COSY operated by KFA Juelich. The excitation functions are measured during the acceleration ramp of COSY. (author)
Density-functional theory based on the electron distribution on the energy coordinate
Takahashi, Hideaki
2018-03-01
We developed an electronic density functional theory utilizing a novel electron distribution n(ɛ) as a basic variable to compute ground state energy of a system. n(ɛ) is obtained by projecting the electron density n({\\boldsymbol{r}}) defined on the space coordinate {\\boldsymbol{r}} onto the energy coordinate ɛ specified with the external potential {\\upsilon }ext}({\\boldsymbol{r}}) of interest. It was demonstrated that the Kohn-Sham equation can also be formulated with the exchange-correlation functional E xc[n(ɛ)] that employs the density n(ɛ) as an argument. It turned out an exchange functional proposed in our preliminary development suffices to describe properly the potential energies of several types of chemical bonds with comparable accuracies to the corresponding functional based on local density approximation. As a remarkable feature of the distribution n(ɛ) it inherently involves the spatially non-local information of the exchange hole at the bond dissociation limit in contrast to conventional approximate functionals. By taking advantage of this property we also developed a prototype of the static correlation functional E sc including no empirical parameters, which showed marked improvements in describing the dissociations of covalent bonds in {{{H}}}2,{{{C}}}2{{{H}}}4 and {CH}}4 molecules.
Binding energy and momentum distribution of nuclear matter using Green's function methods
International Nuclear Information System (INIS)
Ramos, A.; Dickhoff, W.H.; Polls, A.
1991-01-01
The influence of hole-hole (h-h) propagation in addition to the conventional particle-particle (p-p) propagation, on the energy per particle and the momentum distribution is investigated for the v 2 central interaction which is derived from Reid's soft-core potential. The results are compared to Brueckner-Hartree-Fock calculations with a continuous choice for the single-particle (SP) spectrum. Calculation of the energy from a self-consistently determined SP spectrum leads to a lower saturation density. This result is not corroborated by calculating the energy from the hole spectral function, which is, however, not self-consistent. A generalization of previous calculations of the momentum distribution, based on a Goldstone diagram expansion, is introduced that allows the inclusion of h-h contributions to all orders. From this result an alternative calculation of the kinetic energy is obtained. In addition, a direct calculation of the potential energy is presented which is obtained from a solution of the ladder equation containing p-p and h-h propagation to all orders. These results can be considered as the contributions of selected Goldstone diagrams (including p-p and h-h terms on the same footing) to the kinetic and potential energy in which the SP energy is given by the quasiparticle energy. The results for the summation of Goldstone diagrams leads to a different momentum distribution than the one obtained from integrating the hole spectral function which in general gives less depletion of the Fermi sea. Various arguments, based partly on the results that are obtained, are put forward that a self-consistent determination of the spectral functions including the p-p and h-h ladder contributions (using a realistic interaction) will shed light on the question of nuclear saturation at a nonrelativistic level that is consistent with the observed depletion of SP orbitals in finite nuclei
Directory of Open Access Journals (Sweden)
Israr Ullah
2017-11-01
Full Text Available In the smart home environment, efficient energy management is a challenging task. Solutions are needed to achieve a high occupant comfort level with minimum energy consumption. User comfort is measured in terms of three fundamental parameters: (a thermal comfort, (b visual comfort and (c air quality. Temperature, illumination and CO 2 sensors are used to collect indoor contextual information. In this paper, we have proposed an improved optimization function to achieve maximum user comfort in the building environment with minimum energy consumption. A comprehensive formulation is done for energy optimization with detailed analysis. The Kalman filter algorithm is used to remove noise in sensor readings by predicting actual parameter values. For optimization, we have used genetic algorithm (GA and particle swarm optimization (PSO algorithms and performed comparative analysis with a baseline scheme on real data collected for a one-month duration in our lab’s indoor environment. Experimental results show that the proposed optimization function has achieved a 27 . 32 % and a 31 . 42 % reduction in energy consumption with PSO and GA, respectively. The user comfort index was also improved by 10 % i.e., from 0 . 86 to 0 . 96 . GA-based optimization results were better than PSO, as it has achieved almost the same user comfort with 4 . 19 % reduced energy consumption. Results show that the proposed optimization function gives better results than the baseline scheme in terms of user comfort and the amount of consumed energy. The proposed system can help with collecting the data about user preferences and energy consumption for long-term analysis and better decision making in the future for efficient resource utilization and overall profit maximization.
Binding energy and momentum distribution of nuclear matter using Green's function methods
International Nuclear Information System (INIS)
Ramos, A.; Dickhoff, W.H.; Polls, A.
1990-07-01
The influence of hole-hole (hh) propagation in addition to the conventional particle-particle (pp) propagation on the energy per particle and the momentum distribution is investigated for two central interactions (v 2 and v 2 l=0 ) which are derived from Reid's soft core potential. The results are compared to Brueckner-Hartree-Fock calculations with a continuous choice for the single-particle (sp) spectrum. Calculation of the energy from a self-consistently determined sp spectrum leads to a lower saturation density. This result is not corroborated by calculating the energy from the hole spectral function which is, however, not self-consistent. A generalization of previous calculations of the momentum distribution based on a Goldstone diagram expansion is introduced which allows the inclusion of hh contributions to all orders. From this result an alternative calculation of the kinetic energy is obtained. In addition, a direct calculation of the potential energy is presented which is obtained from a solution of the ladder equation containing pp and hh propagation to all orders. These results can be considered as the contributions of selected Goldstone diagrams (including pp and hh terms on the same footing) to the kinetic and potential energy in which the sp energy is given by the quasi-article energy. The results for the summation of Goldstone diagrams leads to a different momentum distribution than the one obtained from integrating the hole spectral function which in general gives less depletion of the Fermi sea. Various arguments, based partly on the results that are obtained, are put forward that a self-consistent determination of the spectral functions including the pp and hh ladder contributions (using a realistic interaction) will shed light on the question of nuclear saturation at a non-relativistic level which is consistent with the observed depletion of sp orbitals in finite nuclei. (Author) (51 refs., 3 tabs., 15 figs)
Directory of Open Access Journals (Sweden)
Sajid Rafique
2014-04-01
Full Text Available Over the past few years, remarkable developments in piezoelectric materials have motivated many researchers to work in the field of vibration energy harvesting by using piezoelectric beam like smart structures. This paper aimed to present the most recent application of a dual function piezoelectric device which can suppress vibration and harvest vibration energy simultaneously and a brief illustration of conventional mechanical and electrical TVAs (Tuned Vibration Absorber. It is shown that the proposed dual function device combines the benefits of conventional mechanical and electrical TVAs and reduces their relative disadvantages. Conversion of mechanical energy into electrical energy introduces damping and, hence, the optimal damping required by this TVA is generated by the energy harvesting effects. This paper presents the methodology of implementing the theory of 'electromechanical' TVAs to suppress the response of any real world structure. The work also illustrates the prospect of extensive applications of such novel "electromechanical" TVAs in defence and industry. The results show that the optimum degree of vibration suppression of an electronic box is achieved by this dual function TVA through suitable tuning of the attached electrical circuitry
Total reflection coefficients of low-energy photons presented as universal functions
Directory of Open Access Journals (Sweden)
Ljubenov Vladan
2010-01-01
Full Text Available The possibility of expressing the total particle and energy reflection coefficients of low-energy photons in the form of universal functions valid for different shielding materials is investigated in this paper. The analysis is based on the results of Monte Carlo simulations of photon reflection by using MCNP, FOTELP, and PENELOPE codes. The normal incidence of the narrow monoenergetic photon beam of the unit intensity and of initial energies from 20 keV up to 100 keV is considered, and particle and energy reflection coefficients from the plane homogenous targets of water, aluminum, and iron are determined and compared. The representations of albedo coefficients on the initial photon energy, on the probability of large-angle photon scattering, and on the mean number of photon scatterings are examined. It is found out that only the rescaled albedo coefficients dependent on the mean number of photon scatterings have the form of universal functions and these functions are determined by applying the least square method.
International Nuclear Information System (INIS)
Rafique, S.; Shah, S.
2014-01-01
Over the past few years, remarkable developments in piezoelectric materials have motivated many researchers to work in the field of vibration energy harvesting by using piezoelectric beam like smart structures. This paper aimed to present the most recent application of a dual function piezoelectric device which can suppress vibration and harvest vibration energy simultaneously and a brief illustration of conventional mechanical and electrical TVAs (Tuned Vibration Absorber). It is shown that the proposed dual function device combines the benefits of conventional mechanical and electrical TVAs and reduces their relative disadvantages. Conversion of mechanical energy into electrical energy introduces damping and, hence, the optimal damping required by this TVA is generated by the energy harvesting effects. This paper presents the methodology of implementing the theory of electromechanical TVAs to suppress the response of any real world structure. The work also illustrates the prospect of extensive applications of such novel electromechanical TVAs in defence and industry. The results show that the optimum degree of vibration suppression of an electronic box is achieved by this dual function TVA through suitable tuning of the attached electrical circuitry. (author)
Frijia, Stephane; Guhathakurta, Subhrajit; Williams, Eric
2012-02-07
Prior LCA studies take the operational phase to include all energy use within a residence, implying a functional unit of all household activities, but then exclude related supply chains such as production of food, appliances, and household chemicals. We argue that bounding the functional unit to provision of a climate controlled space better focuses the LCA on the building, rather than activities that occur within a building. The second issue explored in this article is how technological change in the operational phase affects life cycle energy. Heating and cooling equipment is replaced at least several times over the lifetime of a residence; improved efficiency of newer equipment affects life cycle energy use. The third objective is to construct parametric models to describe LCA results for a family of related products. We explore these three issues through a case study of energy use of residences: one-story and two-story detached homes, 1,500-3,500 square feet in area, located in Phoenix, Arizona, built in 2002 and retired in 2051. With a restricted functional unit and accounting for technological progress, approximately 30% of a building's life cycle energy can be attributed to materials and construction, compared to 0.4-11% in previous studies.
Development of an Enhanced Payback Function for the Superior Energy Performance Program
Energy Technology Data Exchange (ETDEWEB)
Therkelsen, Peter; Rao, Prakash; McKane, Aimee; Sabouni, Ridah; Sheihing, Paul
2015-08-03
The U.S. DOE Superior Energy Performance (SEP) program provides recognition to industrial and commercial facilities that achieve certification to the ISO 50001 energy management system standard and third party verification of energy performance improvements. Over 50 industrial facilities are participating and 28 facilities have been certified in the SEP program. These facilities find value in the robust, data driven energy performance improvement result that the SEP program delivers. Previous analysis of SEP certified facility data demonstrated the cost effectiveness of SEP and identified internal staff time to be the largest cost component related to SEP implementation and certification. This paper analyzes previously reported and newly collected data of costs and benefits associated with the implementation of an ISO 50001 and SEP certification. By disaggregating “sunk energy management system (EnMS) labor costs”, this analysis results in a more accurate and detailed understanding of the costs and benefits of SEP participation. SEP is shown to significantly improve and sustain energy performance and energy cost savings, resulting in a highly attractive return on investment. To illustrate these results, a payback function has been developed and is presented. On average facilities with annual energy spend greater than $2M can expect to implement SEP with a payback of less than 1.5 years. Finally, this paper also observes and details decreasing facility costs associated with implementing ISO 50001 and certifying to the SEP program, as the program has improved from pilot, to demonstration, to full launch.
Dynamic energy landscapes of riboswitches help interpret conformational rearrangements and function.
Directory of Open Access Journals (Sweden)
Giulio Quarta
Full Text Available Riboswitches are RNAs that modulate gene expression by ligand-induced conformational changes. However, the way in which sequence dictates alternative folding pathways of gene regulation remains unclear. In this study, we compute energy landscapes, which describe the accessible secondary structures for a range of sequence lengths, to analyze the transcriptional process as a given sequence elongates to full length. In line with experimental evidence, we find that most riboswitch landscapes can be characterized by three broad classes as a function of sequence length in terms of the distribution and barrier type of the conformational clusters: low-barrier landscape with an ensemble of different conformations in equilibrium before encountering a substrate; barrier-free landscape in which a direct, dominant "downhill" pathway to the minimum free energy structure is apparent; and a barrier-dominated landscape with two isolated conformational states, each associated with a different biological function. Sharing concepts with the "new view" of protein folding energy landscapes, we term the three sequence ranges above as the sensing, downhill folding, and functional windows, respectively. We find that these energy landscape patterns are conserved in various riboswitch classes, though the order of the windows may vary. In fact, the order of the three windows suggests either kinetic or thermodynamic control of ligand binding. These findings help understand riboswitch structure/function relationships and open new avenues to riboswitch design.
A Game for Energy-Aware Allocation of Virtualized Network Functions
Directory of Open Access Journals (Sweden)
Roberto Bruschi
2016-01-01
Full Text Available Network Functions Virtualization (NFV is a network architecture concept where network functionality is virtualized and separated into multiple building blocks that may connect or be chained together to implement the required services. The main advantages consist of an increase in network flexibility and scalability. Indeed, each part of the service chain can be allocated and reallocated at runtime depending on demand. In this paper, we present and evaluate an energy-aware Game-Theory-based solution for resource allocation of Virtualized Network Functions (VNFs within NFV environments. We consider each VNF as a player of the problem that competes for the physical network node capacity pool, seeking the minimization of individual cost functions. The physical network nodes dynamically adjust their processing capacity according to the incoming workload, by means of an Adaptive Rate (AR strategy that aims at minimizing the product of energy consumption and processing delay. On the basis of the result of the nodes’ AR strategy, the VNFs’ resource sharing costs assume a polynomial form in the workflows, which admits a unique Nash Equilibrium (NE. We examine the effect of different (unconstrained and constrained forms of the nodes’ optimization problem on the equilibrium and compare the power consumption and delay achieved with energy-aware and non-energy-aware strategy profiles.
Energy-based Lyapunov functions for forced Hamiltonian systems with dissipation
Maschke, Bernhard M.J.; Ortega, Romeo; Schaft, Arjan J. van der
1998-01-01
It is well known that the total energy is a suitable Lyapunov function to study the stability of the trivial equilibrium of an isolated standard Hamiltonian system. In many practical instances, however, the system is in interaction with its environment through some constant forcing terms. This gives
Ab initio and work function and surface energy anisotropy of LaB6
Uijttewaal, M. A.; de Wijs, G. A.; de Groot, R. A.
2006-01-01
Lanthanum hexaboride is one of the cathode materials most used in high-power electronics technology, but the many experimental results do not provide a consistent picture of the surface properties. Therefore, we report the first ab initio calculations of the work functions and surface energies of
Four-body wave function of π3He-system at the threshold energy
International Nuclear Information System (INIS)
Pupyshev, V.V.; Rakityanskij, S.A.
1985-01-01
On the basis of approximate four-body equations the wave function of π 3 He-system is calculated at zero kinetic energy of the pion. In the case when distances between all four particles are comparable with the nucleus size a strong distortion of the wave function of (3N)-subsystem caused by the presence of the pion is found. The calculated four-body function is represented in a semianalytical form, which makes it possible to apply it in different calculations
Accurate correlation energies in one-dimensional systems from small system-adapted basis functions
Baker, Thomas E.; Burke, Kieron; White, Steven R.
2018-02-01
We propose a general method for constructing system-dependent basis functions for correlated quantum calculations. Our construction combines features from several traditional approaches: plane waves, localized basis functions, and wavelets. In a one-dimensional mimic of Coulomb systems, it requires only 2-3 basis functions per electron to achieve high accuracy, and reproduces the natural orbitals. We illustrate its effectiveness for molecular energy curves and chains of many one-dimensional atoms. We discuss the promise and challenges for realistic quantum chemical calculations.
International Nuclear Information System (INIS)
Kramer, T; Heller, E J; Parrott, R E
2008-01-01
Time-dependent quantum mechanics provides an intuitive picture of particle propagation in external fields. Semiclassical methods link the classical trajectories of particles with their quantum mechanical propagation. Many analytical results and a variety of numerical methods have been developed to solve the time-dependent Schroedinger equation. The time-dependent methods work for nearly arbitrarily shaped potentials, including sources and sinks via complex-valued potentials. Many quantities are measured at fixed energy, which is seemingly not well suited for a time-dependent formulation. Very few methods exist to obtain the energy-dependent Green function for complicated potentials without resorting to ensemble averages or using certain lead-in arrangements. Here, we demonstrate in detail a time-dependent approach, which can accurately and effectively construct the energy-dependent Green function for very general potentials. The applications of the method are numerous, including chemical, mesoscopic, and atomic physics
Duignan, Timothy T.; Baer, Marcel D.; Schenter, Gregory K.; Mundy, Chistopher J.
2017-10-01
Determining the solvation free energies of single ions in water is one of the most fundamental problems in physical chemistry and yet many unresolved questions remain. In particular, the ability to decompose the solvation free energy into simple and intuitive contributions will have important implications for models of electrolyte solution. Here, we provide definitions of the various types of single ion solvation free energies based on different simulation protocols. We calculate solvation free energies of charged hard spheres using density functional theory interaction potentials with molecular dynamics simulation and isolate the effects of charge and cavitation, comparing to the Born (linear response) model. We show that using uncorrected Ewald summation leads to unphysical values for the single ion solvation free energy and that charging free energies for cations are approximately linear as a function of charge but that there is a small non-linearity for small anions. The charge hydration asymmetry for hard spheres, determined with quantum mechanics, is much larger than for the analogous real ions. This suggests that real ions, particularly anions, are significantly more complex than simple charged hard spheres, a commonly employed representation.
Range-separated density-functional theory for molecular excitation energies
International Nuclear Information System (INIS)
Rebolini, E.
2014-01-01
Linear-response time-dependent density-functional theory (TDDFT) is nowadays a method of choice to compute molecular excitation energies. However, within the usual adiabatic semi-local approximations, it is not able to describe properly Rydberg, charge-transfer or multiple excitations. Range separation of the electronic interaction allows one to mix rigorously density-functional methods at short range and wave function or Green's function methods at long range. When applied to the exchange functional, it already corrects most of these deficiencies but multiple excitations remain absent as they need a frequency-dependent kernel. In this thesis, the effects of range separation are first assessed on the excitation energies of a partially-interacting system in an analytic and numerical study in order to provide guidelines for future developments of range-separated methods for excitation energy calculations. It is then applied on the exchange and correlation TDDFT kernels in a single-determinant approximation in which the long-range part of the correlation kernel vanishes. A long-range frequency-dependent second-order correlation kernel is then derived from the Bethe-Salpeter equation and added perturbatively to the range-separated TDDFT kernel in order to take into account the effects of double excitations. (author)
Measurement of the electron structure function F2e at LEP energies
Directory of Open Access Journals (Sweden)
J. Abdallah
2014-10-01
Full Text Available The hadronic part of the electron structure function F2e has been measured for the first time, using e+e− data collected by the DELPHI experiment at LEP, at centre-of-mass energies of s=91.2–209.5 GeV. The data analysis is simpler than that of the measurement of the photon structure function. The electron structure function F2e data are compared to predictions of phenomenological models based on the photon structure function. It is shown that the contribution of large target photon virtualities is significant. The data presented can serve as a cross-check of the photon structure function F2γ analyses and help in refining existing parameterisations.
Measurement of the electron structure function F{sub 2}{sup e} at LEP energies
Energy Technology Data Exchange (ETDEWEB)
Abdallah, J. [LPNHE, IN2P3-CNRS, Univ. Paris VI et VII, 4 place Jussieu, FR-75252 Paris Cedex 05 (France); Abreu, P. [LIP, IST, FCUL, Av. Elias Garcia, 14-1" o, PT-1000 Lisboa Codex (Portugal); Adam, W. [Institut für Hochenergiephysik, Österr. Akad. d. Wissensch., Nikolsdorfergasse 18, AT-1050 Vienna (Austria); Adzic, P. [Institute of Nuclear Physics, N.C.S.R. Demokritos, P.O. Box 60228, GR-15310 Athens (Greece); Albrecht, T. [Institut für Experimentelle Kernphysik, Universität Karlsruhe, Postfach 6980, DE-76128 Karlsruhe (Germany); Alemany-Fernandez, R. [CERN, CH-1211 Geneva 23 (Switzerland); Allmendinger, T. [Institut für Experimentelle Kernphysik, Universität Karlsruhe, Postfach 6980, DE-76128 Karlsruhe (Germany); Allport, P.P. [Department of Physics, University of Liverpool, P.O. Box 147, Liverpool L69 3BX (United Kingdom); Amaldi, U. [Dipartimento di Fisica, Univ. di Milano-Bicocca and INFN-Milano, Piazza della Scienza 3, IT-20126 Milan (Italy); Amapane, N. [Dipartimento di Fisica Sperimentale, Università di Torino and INFN, Via P. Giuria 1, IT-10125 Turin (Italy); Amato, S. [Univ. Federal do Rio de Janeiro, C.P. 68528 Cidade Univ., Ilha do Fundão, BR-21945-970 Rio de Janeiro (Brazil); Anashkin, E. [Dipartimento di Fisica, Università di Padova and INFN, Via Marzolo 8, IT-35131 Padua (Italy); Andreazza, A. [Dipartimento di Fisica, Università di Milano and INFN-Milano, Via Celoria 16, IT-20133 Milan (Italy); Andringa, S.; Anjos, N. [LIP, IST, FCUL, Av. Elias Garcia, 14-1" o, PT-1000 Lisboa Codex (Portugal); Antilogus, P. [LPNHE, IN2P3-CNRS, Univ. Paris VI et VII, 4 place Jussieu, FR-75252 Paris Cedex 05 (France); and others
2014-10-07
The hadronic part of the electron structure function F{sub 2}{sup e} has been measured for the first time, using e{sup +}e{sup −} data collected by the DELPHI experiment at LEP, at centre-of-mass energies of √(s)=91.2–209.5 GeV. The data analysis is simpler than that of the measurement of the photon structure function. The electron structure function F{sub 2}{sup e} data are compared to predictions of phenomenological models based on the photon structure function. It is shown that the contribution of large target photon virtualities is significant. The data presented can serve as a cross-check of the photon structure function F{sub 2}{sup γ} analyses and help in refining existing parameterisations.
DART: A Functional-Level Reconfigurable Architecture for High Energy Efficiency
Directory of Open Access Journals (Sweden)
David Raphaël
2008-01-01
Full Text Available Abstract Flexibility becomes a major concern for the development of multimedia and mobile communication systems, as well as classical high-performance and low-energy consumption constraints. The use of general-purpose processors solves flexibility problems but fails to cope with the increasing demand for energy efficiency. This paper presents the DART architecture based on the functional-level reconfiguration paradigm which allows a significant improvement in energy efficiency. DART is built around a hierarchical interconnection network allowing high flexibility while keeping the power overhead low. To enable specific optimizations, DART supports two modes of reconfiguration. The compilation framework is built using compilation and high-level synthesis techniques. A 3G mobile communication application has been implemented as a proof of concept. The energy distribution within the architecture and the physical implementation are also discussed. Finally, the VLSI design of a 0.13 m CMOS SoC implementing a specialized DART cluster is presented.
General Retarded Contact Self-energies in and beyond the Non-equilibrium Green's Functions Method
Kubis, Tillmann; He, Yu; Andrawis, Robert; Klimeck, Gerhard
2016-03-01
Retarded contact self-energies in the framework of nonequilibrium Green's functions allow to model the impact of lead structures on the device without explicitly including the leads in the actual device calculation. Most of the contact self-energy algorithms are limited to homogeneous or periodic, semi-infinite lead structures. In this work, the complex absorbing potential method is extended to solve retarded contact self-energies for arbitrary lead structures, including irregular and randomly disordered leads. This method is verified for regular leads against common approaches and on physically equivalent, but numerically different irregular leads. Transmission results on randomly alloyed In0.5Ga0.5As structures show the importance of disorder in the leads. The concept of retarded contact self-energies is expanded to model passivation of atomically resolved surfaces without explicitly increasing the device's Hamiltonian.
Directory of Open Access Journals (Sweden)
J. Park
2010-06-01
Full Text Available An energy-conservative metric based on the discrete wavelet transform is applied to assess the relative energy distribution of extreme sea level events across different temporal scales. The metric is applied to coastal events at Key West and Pensacola Florida as a function of two Atlantic Multidecadal Oscillation (AMO regimes. Under AMO warm conditions there is a small but significant redistribution of event energy from nearly static into more dynamic (shorter duration timescales at Key West, while at Pensacola the AMO-dependent changes in temporal event behaviour are less pronounced. Extreme events with increased temporal dynamics might be consistent with an increase in total energy of event forcings which may be a reflection of more energetic storm events during AMO warm phases. As dynamical models mature to the point of providing regional climate index predictability, coastal planners may be able to consider such temporal change metrics in planning scenarios.
New One-Boson-Exchange Potential functions | Fiase | Journal of ...
African Journals Online (AJOL)
A new one-boson-exchange potential (OBEP) is derived by fitting the oscillator matrix elements of the sum of the OBEP functions to those of the matrix elements derived by the lowest order constrained variational (LOCV) technique. The results give a reasonable fit to the OBEP model. Journal of the Nigerian Association of ...
Energy-efficient specialization of functional units in a Coarse-Grained Reconfigurable Array
International Nuclear Information System (INIS)
Van Essen, B.; Panda, R.; Wood, A.; Ebeling, C.; Hauck, S.
2010-01-01
Functional units provide the backbone of any spatial accelerator by providing the computing resources. The desire for having rich and expensive functional units is in tension with producing a regular and energy-efficient computing fabric. This paper explores the design trade-off between complex, universal functional units and simpler, limited functional units. We show that a modest amount of specialization reduces the area-delay-energy product of an optimized architecture to 0.86x a baseline architecture. Furthermore, we provide a design guideline that allows an architect to customize the contents of the computing fabric just by examining the profile of benchmarks within the application domains. Functional units are the core of compute-intensive spatial accelerators. They perform the computation of interest with support from local storage and communication structures. Ideally, the functional units will provide rich functionality, supporting operations ranging from simple addition, to fused multiply-adds, to advanced transcendental functions and domain specific operations like add-compare-select. However, the total opportunity cost to support the more complex operations is a function of the cost of the hardware, the rate of occurrence of the operation in the application domain, and the inefficiency of emulating the operation with simpler operators. Examples of operations that are typically emulated in spatial accelerators are division and trigonometric functions, which can be solved using table-lookup based algorithms and the CORDIC algorithm. One reason to avoid having direct hardware support for complex operations in a tiled architecture like a Coarse-Grained Reconfigurable Array (CGRA) is that the expensive hardware will typically need to be replicated in some or all of the architecture's tiles. Tiled architecture are designed such that their tiles are either homogeneous or heterogeneous. Homogeneous architectures are simpler to design but heterogeneous
Bending energy penalty enhances the adhesive strength of functional amyloid curli to surfaces
Zhang, Yao; Wang, Ao; DeBenedictis, Elizabeth P.; Keten, Sinan
2017-11-01
The functional amyloid curli fiber, a major proteinaceous component of biofilm extracellular matrices, plays an important role in biofilm formation and enterobacteriaceae adhesion. Curli nanofibers exhibit exceptional underwater adhesion to various surfaces, have high rigidity and strong tensile mechanical properties, and thus hold great promise in biomaterials. The mechanisms of how curli fibers strongly attach to surfaces and detach under force remain elusive. To investigate curli fiber adhesion to surfaces, we developed a coarse-grained curli fiber model, in which the protein subunit CsgA (curli specific gene A) self-assembles into the fiber. The coarse-grained model yields physiologically relevant and tunable bending rigidity and persistence length. The force-induced desorption of a single curli fiber is examined using coarse-grained modeling and theoretical analysis. We find that the bending energy penalty arising from high persistence length enhances the resistance of the curli fiber against desorption and thus strengthens the adhesion of the curli fiber to surfaces. The CsgA-surface adhesion energy and the curli fiber bending rigidity both play crucial roles in the resistance of curli fiber against desorption from surfaces. To enable the desorption process, the applied peeling force must overcome both the interfacial adhesion energy and the energy barrier for bending the curli fiber at the peeling front. We show that the energy barrier to desorption increases with the interfacial adhesion energy, however, the bending induced failure of a single curli fiber limits the work of adhesion if the proportion of the CsgA-surface adhesion energy to the CsgA-CsgA cohesive energy becomes large. These results illustrate that the optimal adhesion performance of nanofibers is dictated by the interplay between bending, surface energy and cohesive energy. Our model provides timely insight into enterobacteriaceae adhesion mechanisms as well as future designs of engineered
Du, A. M.; Tsurutani, B. T.; Sun, W.
2012-04-01
Sudden energy release (ER) events in the midnight sector at auroral zone latitudes during intense (B > 10 nT), long-duration (T > 3 hr), northward (Bz > 0 nT = N) IMF magnetic clouds (MCs) during solar cycle 23 (SC23) have been examined in detail. The MCs with northward-then-southward (NS) IMFs were analyzed separately from MCs with southward-then-northward (SN) configurations. It is found that there is a lack of substorms during the N field intervals of NS clouds. In sharp contrast, ER events do occur during the N field portions of SN MCs. From the above two results it is reasonable to conclude that the latter ER events represent residual energy remaining from the preceding S portions of the SN MCs. We derive a new solar wind-magnetosphere coupling function during northward IMFs: ENIMF = α N-1/12V 7/3B1/2 + β V |Dstmin|. The first term on the right-hand side of the equation represents the energy input via "viscous interaction", and the second term indicates the residual energy stored in the magnetotail. It is empirically found that the magnetosphere/magnetotail can store energy for a maximum of ~ 4 hrs before it has dissipated away. This concept is defining one for ER/substorm energy storage. Our scenario indicates that the rate of solar wind energy injection into the magnetosphere/magnetotail determines the form of energy release into the magnetosphere/ionosphere. This may be more important than the dissipation mechanism itself (in understanding the form of the release). The concept of short-term energy storage is applied for the solar case. It is argued that it may be necessary to identify the rate of energy input into solar magnetic loop systems to be able to predict the occurrence of solar flares.
The Analytical Potential Energy Function of NH Radical Molecule in External Electric Field
International Nuclear Information System (INIS)
Wu Dong-Lan; Tan Bin; Wan Hui-Jun; Xie An-Dong; Ding Da-Jun
2015-01-01
The geometric structures of an NH radical in different external electric fields are optimized by using the density functional B3P86/cc-PV5Z method, and the bond lengths, dipole moments, vibration frequencies and IR spectrum are obtained. The potential energy curves are gained by the CCSD (T) method with the same basis set. These results indicate that the physical property parameters and potential energy curves may change with the external electric field, especially in the reverse direction electric field. The potential energy function of zero field is fitted by the Morse potential, and the fitting parameters are in good accordance with the experimental data. The potential energy functions of different external electric fields are fitted adopting the constructed potential model. The fitted critical dissociation electric parameters are shown to be consistent with the numerical calculation, and the relative errors are only 0.27% and 6.61%, hence the constructed model is reliable and accurate. The present results provide an important reference for further study of the molecular spectrum, dynamics and molecular cooling with Stark effect. (paper)
Low-energy ion distribution functions on a magnetically quiet day at geostationary altitude (L = 7)
International Nuclear Information System (INIS)
Singh, N.; Raitt, W.J.; Yasuhara, F.
1982-01-01
By using averaged data from ATS 6, ion energy and pitch angle distribution functions were examined for a magnetically quiet day (July 18, 1974). The data showed that for both field-aligned and perpendicular fluxes, the population had a mixture of characteristic energies. It was found that over three different energy bands in the range 3-600 eV the distribution functions could be fairly well approximated by Maxwellian distributions with temperatures in the ranges 3-10 eV, 30-50 eV, and approximately 70 eV in energy bands of 3-30 eV, 30-140 eV, and 140-600 eV, respectively. Pitch angle distributions were found to vary the local time; strong field-aligned particle fluxes were measured in the midnight and afternoon sectors, minor field-aligned components persisted to some extent at all times, especially at low energies (E 0 was seen. By using the assumption that the plasma was corotating with the satellite, we have examined pitch angle scattering mechanisms responsible for the observed transformation of pitch angle distribution. It was found that a magnetic noise of power spectral density b 2 -3 γ 2 /Hz belonging to electromagnetic ion cyclotron mode (L mode) near the ion cyclotron frequency could be very effective in trapping the field-aligned fluxes by pitch angle scattering
Development of multi-functional nano-paint for energy harvesting applications
Directory of Open Access Journals (Sweden)
Bir B. Bohara
2018-02-01
Full Text Available The multi-functionality of lead magnesium niobate-lead titanate/paint (PMN-PT/paint nanocomposite films for energy harvesting via piezoelectric and pyroelectric effects is described. PMN-PT/paint films have been fabricated by a conventional paint-brushing technique to provide a low-cost, low-temperature and low–energy route to create multi-functional films. The properties investigated included dielectric constants, ε' and ε'', as a function of temperature, frequency and composition. From these parameters, it is indicated that the dielectric constants and AC conductivity (σAC increase with an increase of filler content and temperature, implying an improvement of the functionality of the films. The results revealed that σAC obeyed the relation σAC = Aωs, and exponent s, was found to decrease by increasing the temperature. The correlated barrier hopping was the dominant conduction mechanism in the nanocomposite films. The efforts were made to investigate the performance of nanocomposite films to mechanical vibrations and thermal variations. A cantilever system was designed and examined to assess its performance as energy harvesters. The highest output voltage and power for a PMN-PT/paint based harvester with a broad frequency response operating in the -31-piezoelectric mode were 65 mV and 1 nW, respectively. Voltage and power were shown to be enhanced by application of thermal variations. Thus, films could be utilized for combined energy harvesting via piezoelectric and pyroelectric characteristics. Keywords: Dielectric, Pyroelectricity, Piezoelectricity, Nanocomposites, PMN-PT, Energy harvesting
Perakakis, Nikolaos; Upadhyay, Jagriti; Ghaly, Wael; Chen, Joyce; Chrysafi, Pavlina; Anastasilakis, Athanasios D; Mantzoros, Christos S
2018-05-09
We have previously demonstrated that the adipose tissue derived hormone leptin controls reproductive function by regulating the hypothalamic-pituitary-gonadal axis in response to energy deficiency. Here, we evaluate the activins-follistatins-inhibins (AFI) axis during acute (short-term fasting in healthy people) and chronic energy deficiency (women with hypothalamic amenorrhea due to strenuous exercise [HA]) and investigate their relation to leptin and reproductive function in healthy subjects and subjects with HA. The AFI axis was investigated in: a) A double-blinded study in healthy subjects having three randomly assigned admissions, each time for four days: in the isocaloric fed state, complete fasting with placebo treatment, complete fasting with leptin replacement, b) A case-control study comparing women with HA vs healthy controls, c) An open-label interventional study investigating leptin treatment in women with HA over a period of up to three months, d) A randomized interventional trial investigating leptin treatment vs placebo in women with HA for nine months. The circulating levels of activin A, activin B, follistatin and follistatin-like 3 change robustly in response to acute and chronic energy deficiency. Leptin replacement in acute energy deprivation does not affect the levels of these hormones suggesting an independent regulation by these two hormonal pathways. In chronic energy deficiency, leptin replacement restores only activin B levels, which are in turn associated with an increase in the number of dominant follicles. We demonstrate for the first time that the AFI axis is affected both by acute and chronic energy deficiency. Partial restoration of a component of the axis, i.e. activin B only, through leptin replacement is associated with improved reproductive function in women with HA. Copyright © 2018. Published by Elsevier Inc.
Torbeyns, Tine; de Geus, Bas; Bailey, Stephen; Decroix, Lieselot; Van Cutsem, Jeroen; De Pauw, Kevin; Meeusen, Romain
2017-06-01
Physical activity is positively associated with physical health, cognitive performance, brain functioning and academic performance. The aim of this study is to investigate the influence of bike desks in the classroom on adolescents' energy expenditure, physical health, cognitive performance, brain functioning and academic performance. Forty-four adolescents were randomly assigned to control group (CG) or intervention group (IG). During 5 months, the IG used a bike desk for 4 class hours/week. Energy expenditure was measured during 6 consecutive days. Anthropometric parameters, aerobic fitness, academic performance, cognitive performance and brain functioning were assessed before (T0) and after (T1) the intervention. Energy expenditure of the IG was significantly higher during the class hours in which they used the bike desks relative to normal class hours. The CG had a significantly higher BMI at T1 relative to T0 while this was not significantly different for the IG. Aerobic fitness was significantly better in the IG at T1 relative to T0. No significant effects on academic performance cognitive performance and brain functioning were observed. As the implementation of bike desks in the classroom did not interfere with adolescents' academic performance, this can be seen as an effective means of reducing in-class sedentary time and improving adolescents' physical health.
International Nuclear Information System (INIS)
Quijada, M.; Borisov, A.G.; Muino, R.D.
2008-01-01
Time-dependent density functional theory is used to study the interaction between antiprotons and metallic nanoshells. The ground state electronic properties of the nanoshell are obtained in the jellium approximation. The energy lost by the antiproton during the collision is calculated and compared to that suffered by antiprotons traveling in metal clusters. The resulting energy loss per unit path length of material in thin nanoshells is larger than the corresponding quantity for clusters. It is shown that the collision process can be interpreted as the antiproton crossing of two nearly bi-dimensional independent metallic systems. (copyright 2008 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)
Gaussian-3 theory using density functional geometries and zero-point energies
International Nuclear Information System (INIS)
Baboul, A.G.; Curtiss, L.A.; Redfern, P.C.; Raghavachari, K.
1999-01-01
A variation of Gaussian-3 (G3) theory is presented in which the geometries and zero-point energies are obtained from B3LYP density functional theory [B3LYP/6-31G(d)] instead of geometries from second-order perturbation theory [MP2(FU)/6-31G(d)] and zero-point energies from Hartree - Fock theory [HF/6-31G(d)]. This variation, referred to as G3//B3LYP, is assessed on 299 energies (enthalpies of formation, ionization potentials, electron affinities, proton affinities) from the G2/97 test set [J. Chem. Phys. 109, 42 (1998)]. The G3//B3LYP average absolute deviation from experiment for the 299 energies is 0.99 kcal/mol compared to 1.01 kcal/mol for G3 theory. Generally, the results from the two methods are similar, with some exceptions. G3//B3LYP theory gives significantly improved results for several cases for which MP2 theory is deficient for optimized geometries, such as CN and O 2 + . However, G3//B3LYP does poorly for ionization potentials that involve a Jahn - Teller distortion in the cation (CH 4 + , BF 3 + , BCl 3 + ) because of the B3LYP/6-31G(d) geometries. The G3(MP2) method is also modified to use B3LYP/6-31G(d) geometries and zero-point energies. This variation, referred to as G3(MP2)//B3LYP, has an average absolute deviation of 1.25 kcal/mol compared to 1.30 kcal/mol for G3(MP2) theory. Thus, use of density functional geometries and zero-point energies in G3 and G3(MP2) theories is a useful alternative to MP2 geometries and HF zero-point energies. copyright 1999 American Institute of Physics
Non-local energy density functionals: models plus some exact general results
International Nuclear Information System (INIS)
March, N.H.
2001-02-01
Holas and March (Phys. Rev. A51, 2040, 1995) gave a formally exact expression for the force - δV xc (r-tilde)/δr-tilde associated with the exchange-correlation potential V xc (r-tilde) of density functional theory. This forged a precise link between first- and second-order density matrices and V xc (r-tilde). Here models are presented in which these low-order matrices can be related to the ground-state electron density. This allows non-local energy density functionals to be constructed within the framework of such models. Finally, results emerging from these models have led to the derivation of some exact 'nuclear cusp' relations for exchange and correlation energy densities in molecules, clusters and condensed phases. (author)
The calculations of small molecular conformation energy differences by density functional method
Topol, I. A.; Burt, S. K.
1993-03-01
The differences in the conformational energies for the gauche (G) and trans(T) conformers of 1,2-difluoroethane and for myo-and scyllo-conformer of inositol have been calculated by local density functional method (LDF approximation) with geometry optimization using different sets of calculation parameters. It is shown that in the contrast to Hartree—Fock methods, density functional calculations reproduce the correct sign and value of the gauche effect for 1,2-difluoroethane and energy difference for both conformers of inositol. The results of normal vibrational analysis for1,2-difluoroethane showed that harmonic frequencies calculated in LDF approximation agree with experimental data with the accuracy typical for scaled large basis set Hartree—Fock calculations.
Functional integration of vertical flight path and speed control using energy principles
Lambregts, A. A.
1984-01-01
A generalized automatic flight control system was developed which integrates all longitudinal flight path and speed control functions previously provided by a pitch autopilot and autothrottle. In this design, a net thrust command is computed based on total energy demand arising from both flight path and speed targets. The elevator command is computed based on the energy distribution error between flight path and speed. The engine control is configured to produce the commanded net thrust. The design incorporates control strategies and hierarchy to deal systematically and effectively with all aircraft operational requirements, control nonlinearities, and performance limits. Consistent decoupled maneuver control is achieved for all modes and flight conditions without outer loop gain schedules, control law submodes, or control function duplication.
Energy-momentum tensor correlation function in Nf = 2 + 1 full QCD at finite temperature
Taniguchi, Yusuke; Ejiri, Shinji; Kanaya, Kazuyuki; Kitazawa, Masakiyo; Suzuki, Asobu; Suzuki, Hiroshi; Umeda, Takashi
2018-03-01
We measure correlation functions of the nonperturbatively renormalized energy-momentum tensor in Nf = 2 + 1 full QCD at finite temperature by applying the gradient flow method both to the gauge and quark fields. Our main interest is to study the conservation law of the energy-momentum tensor and to test whether the linear response relation is properly realized for the entropy density. By using the linear response relation we calculate the specific heat from the correlation function. We adopt the nonperturba-tively improved Wilson fermion and Iwasaki gauge action at a fine lattice spacing = 0:07 fm. In this paper the temperature is limited to a single value T ≃ 232 MeV. The u, d quark mass is rather heavy with mπ=mρ ≃ 0:63 while the s quark mass is set to approximately its physical value.
Energy-momentum tensor correlation function in Nf = 2 + 1 full QCD at finite temperature
Directory of Open Access Journals (Sweden)
Taniguchi Yusuke
2018-01-01
Full Text Available We measure correlation functions of the nonperturbatively renormalized energy-momentum tensor in Nf = 2 + 1 full QCD at finite temperature by applying the gradient flow method both to the gauge and quark fields. Our main interest is to study the conservation law of the energy-momentum tensor and to test whether the linear response relation is properly realized for the entropy density. By using the linear response relation we calculate the specific heat from the correlation function. We adopt the nonperturba-tively improved Wilson fermion and Iwasaki gauge action at a fine lattice spacing = 0:07 fm. In this paper the temperature is limited to a single value T ≃ 232 MeV. The u, d quark mass is rather heavy with mπ=mρ ≃ 0:63 while the s quark mass is set to approximately its physical value.
International Nuclear Information System (INIS)
Barut, A.O.; Anders, T.B.; Jachmann, W.
1992-06-01
The experimental data for the polarization asymmetries of pp-scattering available at the scattering angle θ = 90 deg. and at various moderate energies, as well as at E = 2.4434 GeV and various scattering angles are described by smooth phenomenological coupling functions for scalar, vector, tensor and the ''magnetic moment'' couplings as well as the corresponding parity conserving axial couplings. The analysis shows a predominant role of the ''axial magnetic moment'', the axial scalar, and the axial vector interactions. Moreover, the data contain oscillations of the type sin(qw 0 -π)/(qw 0 -π), where q is the square root of the energy-momentum transfer. The oscillations have amplitudes of 5%, and a constant frequency w o = 2π/0.88 m p . They arise from oscillating modulations up to 25% of the non-axial coupling functions. 8 refs, 21 figs, 4 tabs
Directory of Open Access Journals (Sweden)
Mohammad Javad Mahdavinejad
2015-03-01
Full Text Available Man raises level of his needs by falsifying the nature and construction of the built spaces. By examining various aspects and complex dimensions of the human, variable and different needs can be clearly seen. Therefore, an architectural construction, especially housing, should be able to set the access conditions to meet the highest level of the needs and achieve to the highest level of responsiveness to the needs of users. Thus, conditions such as flexibility, adaptability, variability and all the principles that lead to generate opportunities and capacities proportional to user's needs in a building has been double necessary. With looking at the traditional architecture, we find that, despite the limitations in manufacturing technology, the architects used their own strategies for responding to existing problems. Strategies such as the use of multi-functional space, embedding spaces in the three scales of tiny, medium and large scales as well as ability to separate or merge spaces, are some of these items. By knowing, however, Iran's traditional home space is flexible, in this study, we sought to answer the question whether this flexibility in space has a role in the amount of energy consumption of the building? If there is, it has an increasing or decreasing role? In order to answer this question, several examples of traditional houses in the hot and dry climates is simulated that, due to brevity it is not expressed in this study. Among them, for example, is expressed Boroujerdi House and energy consumption of the existing state compared with when a space had not seasonal versatility. Finally, it is concluded that flexibility, reduce energy consumption in traditional buildings.
A new analysis technique to measure fusion excitation functions with large beam energy dispersions
Figuera, P.; Di Pietro, A.; Fisichella, M.; Lattuada, M.; Shotter, A. C.; Ruiz, C.; Zadro, M.
2018-01-01
Peculiar nuclear structures of two colliding nuclei such has clustering, neutron halo/skin or very low breakup thresholds can affect the reaction dynamics below the Coulomb barrier and this may also have astrophysical consequences. In order to have a better understanding of this topic, in the last decade, several experiments were performed. A typical experimental challenge of such studies is the need to measure excitation functions below the Coulomb barrier, having a strong energy dependence, with rather large beam energy dispersions inside the target. This may easily lead to ambiguities in associating the measured cross section with a proper beam energy. In this paper a discussion on this topic is reported and a new technique to deal with the above problem will be proposed.
Boll, Torben
2012-10-01
In this article the Cu-Au binding energy in Cu3Au is determined by comparing experimental atom probe tomography (APT) results to simulations. The resulting bonding energy is supported by density functional theory calculations. The APT simulations are based on the Müller-Schottky equation, which is modified to include different atomic neighborhoods and their characteristic bonds. The local environment is considered up to the fifth next nearest neighbors. To compare the experimental with simulated APT data, the AtomVicinity algorithm, which provides statistical information about the positions of the neighboring atoms, is applied. The quality of this information is influenced by the field evaporation behavior of the different species, which is connected to the bonding energies. © Microscopy Society of America 2012.
Energy Technology Data Exchange (ETDEWEB)
Djukanovic, M [Institut Nikola Tesla, Belgrade (Yugoslavia); Sobajic, D J; Pao, Yohhan [Case Western Reserve Univ., Cleveland, OH (United States)
1991-10-01
The identification of the mode of instability plays an essential role in generating principal energy boundary hypersurfaces. We present a new method for unstable machine identification based on the use of supervised learning neural-net technology, and the adaptive pattern recognition concept. It is shown that using individual energy functions as pattern features, appropriately trained neural-nets can retrieve the reliable characterization of the transient process including critical clearing time parameter, mode of instability and energy margins. Generalization capabilities of the neural-net processing allow for these assessments to be made independently of load levels. The results obtained from computer simulations are presented using the New England power system, as an example. (author).
Ebrahimi, Saeed; Vahdatazad, Nader; Liaghat, Gholamhossein
2018-03-01
This paper deals with the energy absorption characterization of functionally graded foam (FGF) filled tubes under axial crushing loads by experimental method. The FGF tubes are filled axially by gradient layers of polyurethane foams with different densities. The mechanical properties of the polyurethane foams are firstly obtained from axial compressive tests. Then, the quasi-static compressive tests are carried out for empty tubes, uniform foam filled tubes and FGF filled tubes. Before to present the experimental test results, a nonlinear FEM simulation of the FGF filled tube is carried out in ABAQUS software to gain more insight into the crush deformation patterns, as well as the energy absorption capability of the FGF filled tube. A good agreement between the experimental and simulation results is observed. Finally, the results of experimental test show that an FGF filled tube has excellent energy absorption capacity compared to the ordinary uniform foam-filled tube with the same weight.
Notman, Rebecca; Anwar, Jamshed; Briels, W. J.; Noro, Massimo G.; den Otter, Wouter K.
2008-01-01
Transmembrane pore formation is central to many biological processes such as ion transport, cell fusion, and viral infection. Furthermore, pore formation in the ceramide bilayers of the stratum corneum may be an important mechanism by which penetration enhancers such as dimethylsulfoxide (DMSO) weaken the barrier function of the skin. We have used the potential of mean constraint force (PMCF) method to calculate the free energy of pore formation in ceramide bilayers in both the innate gel pha...
Modeling nuclear weak-interaction processes with relativistic energy density functionals
International Nuclear Information System (INIS)
Paar, N.; Marketin, T.; Vale, D.; Vretenar, D.
2015-01-01
Relativistic energy density functionals have become a standard framework for nuclear structure studies of ground state properties and collective excitations over the entire nuclide chart. In this paper, we review recent developments in modeling nuclear weak-interaction processes: Charge-exchange excitations and the role of isoscalar proton–neutron pairing, charged-current neutrino–nucleus reactions relevant for supernova evolution and neutrino detectors and calculation of β-decay rates for r-process nucleosynthesis. (author)
Modine, N. A.; Wright, A. F.; Lee, S. R.
The rate of defect-induced carrier recombination is determined by both defect levels and carrier capture cross-sections. Density functional theory (DFT) has been widely and successfully used to predict defect levels, but only recently has work begun to focus on using DFT to determine carrier capture cross-sections. Lang and Henry developed the theory of carrier-capture by multiphonon emission in the 1970s and showed that carrier-capture cross-sections differ between defects primarily due to differences in their carrier capture activation energies. We present an approach to using DFT to calculate carrier capture activation energies that does not depend on an assumed configuration coordinate and that fully accounts for anharmonic effects, which can substantially modify carrier activation energies. We demonstrate our approach for intrinisic defects in GaAs and GaN and discuss how our results depend on the choice of exchange-correlation functional and the treatment of spin polarization. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under Contract DE-AC04-94AL85000.
Dietary Energy Density, Renal Function, and Progression of Chronic Kidney Disease
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Mohammad Hossein Rouhani
2016-01-01
Full Text Available Background. There is evidence of the association between dietary energy density and chronic diseases. However, no report exists regarding the relation between DED and chronic kidney disease (CKD. Objective. To examine the association between dietary energy density (DED, renal function, and progression of chronic kidney disease (CKD. Design. Cross-sectional. Setting. Three nephrology clinics. Subjects. Two hundred twenty-one subjects with diagnosed CKD. Main Outcome Measure. Dietary intake of patients was assessed by a validated food frequency questionnaire. DED (in kcal/g was calculated with the use of energy content and weight of solid foods and energy yielding beverages. Renal function was measured by blood urea nitrogen (BUN, serum creatinine (Cr, and estimated glomerular filtration rate (eGFR. Results. Patients in the first tertile of DED consumed more amounts of carbohydrate, dietary fiber, potassium, phosphorus, zinc, magnesium, calcium, folate, vitamin C, and vitamin B2. After adjusting for confounders, we could not find any significant trend for BUN and Cr across tertiles of DED. In multivariate model, an increased risk of being in the higher stage of CKD was found among those in the last tertile of DED (OR: 3.15; 95% CI: 1.30, 7.63; P=0.01. Conclusion. We observed that lower DED was associated with better nutrient intake and lower risk of CKD progression.
Phipps, M J S; Fox, T; Tautermann, C S; Skylaris, C-K
2017-04-11
First-principles quantum mechanical calculations with methods such as density functional theory (DFT) allow the accurate calculation of interaction energies between molecules. These interaction energies can be dissected into chemically relevant components such as electrostatics, polarization, and charge transfer using energy decomposition analysis (EDA) approaches. Typically EDA has been used to study interactions between small molecules; however, it has great potential to be applied to large biomolecular assemblies such as protein-protein and protein-ligand interactions. We present an application of EDA calculations to the study of ligands that bind to the thrombin protein, using the ONETEP program for linear-scaling DFT calculations. Our approach goes beyond simply providing the components of the interaction energy; we are also able to provide visual representations of the changes in density that happen as a result of polarization and charge transfer, thus pinpointing the functional groups between the ligand and protein that participate in each kind of interaction. We also demonstrate with this approach that we can focus on studying parts (fragments) of ligands. The method is relatively insensitive to the protocol that is used to prepare the structures, and the results obtained are therefore robust. This is an application to a real protein drug target of a whole new capability where accurate DFT calculations can produce both energetic and visual descriptors of interactions. These descriptors can be used to provide insights for tailoring interactions, as needed for example in drug design.
International Nuclear Information System (INIS)
Nomura, K.; Vretenar, D.; Niksic, T.; Otsuka, T.; Shimizu, N.
2011-01-01
Microscopic energy density functionals have become a standard tool for nuclear structure calculations, providing an accurate global description of nuclear ground states and collective excitations. For spectroscopic applications, this framework has to be extended to account for collective correlations related to restoration of symmetries broken by the static mean field, and for fluctuations of collective variables. In this paper, we compare two approaches to five-dimensional quadrupole dynamics: the collective Hamiltonian for quadrupole vibrations and rotations and the interacting boson model (IBM). The two models are compared in a study of the evolution of nonaxial shapes in Pt isotopes. Starting from the binding energy surfaces of 192,194,196 Pt, calculated with a microscopic energy density functional, we analyze the resulting low-energy collective spectra obtained from the collective Hamiltonian, and the corresponding IBM Hamiltonian. The calculated excitation spectra and transition probabilities for the ground-state bands and the γ-vibration bands are compared to the corresponding sequences of experimental states.
New statistical potential for quality assessment of protein models and a survey of energy functions
Directory of Open Access Journals (Sweden)
Rykunov Dmitry
2010-03-01
Full Text Available Abstract Background Scoring functions, such as molecular mechanic forcefields and statistical potentials are fundamentally important tools in protein structure modeling and quality assessment. Results The performances of a number of publicly available scoring functions are compared with a statistical rigor, with an emphasis on knowledge-based potentials. We explored the effect on accuracy of alternative choices for representing interaction center types and other features of scoring functions, such as using information on solvent accessibility, on torsion angles, accounting for secondary structure preferences and side chain orientation. Partially based on the observations made, we present a novel residue based statistical potential, which employs a shuffled reference state definition and takes into account the mutual orientation of residue side chains. Atom- and residue-level statistical potentials and Linux executables to calculate the energy of a given protein proposed in this work can be downloaded from http://www.fiserlab.org/potentials. Conclusions Among the most influential terms we observed a critical role of a proper reference state definition and the benefits of including information about the microenvironment of interaction centers. Molecular mechanical potentials were also tested and found to be over-sensitive to small local imperfections in a structure, requiring unfeasible long energy relaxation before energy scores started to correlate with model quality.
Notman, Rebecca; Anwar, Jamshed; Briels, W J; Noro, Massimo G; den Otter, Wouter K
2008-11-15
Transmembrane pore formation is central to many biological processes such as ion transport, cell fusion, and viral infection. Furthermore, pore formation in the ceramide bilayers of the stratum corneum may be an important mechanism by which penetration enhancers such as dimethylsulfoxide (DMSO) weaken the barrier function of the skin. We have used the potential of mean constraint force (PMCF) method to calculate the free energy of pore formation in ceramide bilayers in both the innate gel phase and in the DMSO-induced fluidized state. Our simulations show that the fluid phase bilayers form archetypal water-filled hydrophilic pores similar to those observed in phospholipid bilayers. In contrast, the rigid gel-phase bilayers develop hydrophobic pores. At the relatively small pore diameters studied here, the hydrophobic pores are empty rather than filled with bulk water, suggesting that they do not compromise the barrier function of ceramide membranes. A phenomenological analysis suggests that these vapor pores are stable, below a critical radius, because the penalty of creating water-vapor and tail-vapor interfaces is lower than that of directly exposing the strongly hydrophobic tails to water. The PMCF free energy profile of the vapor pore supports this analysis. The simulations indicate that high DMSO concentrations drastically impair the barrier function of the skin by strongly reducing the free energy required for pore opening.
[Ionization energies and infrared spectra studies of histidine using density functional theory].
Hu, Qiong; Wang, Guo-Ying; Liu, Gang; Ou, Jia-Ming; Wang, Rui-Li
2010-05-01
Histidines provide axial ligands to the primary electron donors in photosynthetic reaction centers (RCs) and play an important role in the protein environments of these donors. In this paper the authors present a systematic study of ionization energies and vibrational properties of histidine using hybrid density functional theory (DFT). All calculations were undertaken by using B3LYP method in combination with four basis sets: 6-31G(d), 6-31G(df, p), 6-31+G(d) and 6-311+G(2d, 2p) with the aim to investigate how the basis sets influence the calculation results. To investigate solvent effects and gain a detailed understanding of marker bands of histidine, the ionization energies of histidine and the vibrational frequencies of histidine which are unlabeled and 13C, 15N, and 2H labeled in the gas phase, CCl4, protein environment, THF and water solution, which span a wide range of dielectric constant, were also calculated. Our results showed that: (1) The main geometry parameters of histidine were impacted by basis sets and mediums, and C2-N3 and N3-C4 bond of imidazole ring of histidine side chain display the maximum bond lengths in the gas phase; (2) single point energies and frequencies calculated were decreased while ionization energies increased with the increasing level of basis sets and diffuse function applied in the same solvent; (3) with the same computational method, the higher the dielectric constant of the solvent used, the lower the ionization energy and vibrational frequency and the higher the intensity obtained. In addition, calculated ionization energy in the gas phase and marker bands of histidine as well as frequency shift upon 13C and 15N labeling at the computationally more expensive 6-311+G(2d, 2p) level are in good agreement with experimental observations available in literatures. All calculations indicated that the results calculated by using higher level basis set with diffuse function were more accurate and closer to the experimental value. In
Optimizing virtual machine placement for energy and SLA in clouds using utility functions
Directory of Open Access Journals (Sweden)
Abdelkhalik Mosa
2016-10-01
Full Text Available Abstract Cloud computing provides on-demand access to a shared pool of computing resources, which enables organizations to outsource their IT infrastructure. Cloud providers are building data centers to handle the continuous increase in cloud users’ demands. Consequently, these cloud data centers consume, and have the potential to waste, substantial amounts of energy. This energy consumption increases the operational cost and the CO2 emissions. The goal of this paper is to develop an optimized energy and SLA-aware virtual machine (VM placement strategy that dynamically assigns VMs to Physical Machines (PMs in cloud data centers. This placement strategy co-optimizes energy consumption and service level agreement (SLA violations. The proposed solution adopts utility functions to formulate the VM placement problem. A genetic algorithm searches the possible VMs-to-PMs assignments with a view to finding an assignment that maximizes utility. Simulation results using CloudSim show that the proposed utility-based approach reduced the average energy consumption by approximately 6 % and the overall SLA violations by more than 38 %, using fewer VM migrations and PM shutdowns, compared to a well-known heuristics-based approach.
An energy security management model using quality function deployment and system dynamics
International Nuclear Information System (INIS)
Shin, Juneseuk; Shin, Wan-Seon; Lee, Changyong
2013-01-01
An energy security management model using quality function deployment (QFD) and system dynamics (SD) is suggested for application in public policymaking in developing economies. Through QFD, experts are guided toward identifying key energy security components, including indicators and policies, and in making these components consistent, focused, and customized for a particular country. Using these components as inputs, we construct an intermediate complex system dynamics model with a minimal number of crucial interactions. Key policies are simulated and evaluated in terms of the improvement of key indicators. Even with little data, our approach provides a coherent, useful, and customized energy security management model to help policymakers more effectively manage national energy security. To demonstrate its advantages, the model is applied to the Korean gas sector as an example. - Highlights: ► We suggest an energy security management model for developing economies. ► We identify a consistent set of key components, indicators and policies by using QFD. ► A coherent and practical system dynamics model based on QFD's output is constructed. ► The model is applied to the Korean gas sector as an example
Effective Ginzburg–Landau free energy functional for multi-band isotropic superconductors
International Nuclear Information System (INIS)
Grigorishin, Konstantin V.
2016-01-01
Highlights: • The intergradient coupling of order parameters in a two-band superconductor plays important role and cannot be neglected. • A two-band superconductor must be characterized with a single coherence length and a single Ginzburg–Landau parameter. • Type-1.5 superconductors are impossible. • The free energy functional for a multi-band superconductor can be reduced to the effective single-band Ginzburg–Landau functional. - Abstract: It has been shown that interband mixing of gradients of two order parameters (drag effect) in an isotropic bulk two-band superconductor plays important role – such a quantity of the intergradients coupling exists that the two-band superconductor is characterized with a single coherence length and a single Ginzburg–Landau (GL) parameter. Other quantities or neglecting of the drag effect lead to existence of two coherence lengths and dynamical instability due to violation of the phase relations between the order parameters. Thus so-called type-1.5 superconductors are impossible. An approximate method for solving of set of GL equations for a multi-band superconductor has been developed: using the result about the drag effect it has been shown that the free-energy functional for a multi-band superconductor can be reduced to the GL functional for an effective single-band superconductor.
Energy Technology Data Exchange (ETDEWEB)
Sobreira, F.; Rosenfeld, R. [Universidade Estadual Paulista Julio de Mesquita Filho (IFT/UNESP), Sao Paulo, SP (Brazil). Inst. Fisica Teorica; Simoni, F. de; Costa, L.A.N. da; Gaia, M.A.G.; Ramos, B.; Ogando, R.; Makler, M. [Laboratorio Interinstitucional de e-Astronomia (LIneA), Rio de Janeiro, RJ (Brazil)
2011-07-01
Full text: We study the cosmological constraints expected for the upcoming project Dark Energy Survey (DES) with the full functional form of the 2-point angular correlation function. The angular correlation function model applied in this work includes the effects of linear redshift-space distortion, photometric redshift errors (assumed to be Gaussian) and non-linearities prevenient from gravitational infall. The Fisher information matrix is constructed with the full covariance matrix, which takes the correlation between nearby redshift shells in a proper manner. The survey was sliced into 20 redshift shells in the range 0:4 {<=} z {<=} 1:40 with a variable angular scale in order to search only the scale around the signal from the baryon acoustic oscillation, therefore well within the validity of the non-linear model employed. We found that under those assumptions and with a flat {Lambda}CDM WMAP7 fiducial model, the DES will be able to constrain the dark energy equation of state parameter w with a precision of {approx} 20% and the cold dark matter with {approx} 11% when marginalizing over the other 25 parameters (bias is treated as a free parameter for each shell). When applying WMAP7 priors on {Omega}{sub baryon}, {Omega} c{sub dm}, n{sub s}, and HST priors on the Hubble parameter, w is constrained with {approx} 9% precision. This shows that the full shape of the angular correlation function with DES data will be a powerful probe to constrain cosmological parameters. (author)
Intrinsic polarization of the high energy W-boson structure functions
International Nuclear Information System (INIS)
Ralston, J.P.; Olness, F.
1986-01-01
Several new issues are presented that are to be incorporated into a consistent treatment of high-energy transverse effective-W boson structure functions. The issues included the numerical importance of the proper choice of scale, and the q 2 evolution of the boson structure functions in an Altarelli-Parisi framework. We investigate a novel effect of the V-A coupling which produces a sizable intrinsic polarization of the W distributions. A preliminary estimate yields a left- to right-helicity structure function ratio W/sub L// + W/sub R/ + ≅ 1 - 21/(1 - x) + 21/(1 - x) 2 . For x ≥ 0.06, there are two lift-handed W + 's for every right-handed one in an unpolarized proton. 11 refs., 2 figs
Higher-order terms in the nuclear-energy-density functional
International Nuclear Information System (INIS)
Carlsson, B. G.; Borucki, M.; Dobaczewski, J.
2009-01-01
One of the current projects at the Department of Physics in the University of Jyvaeskylae is to explore more general forms of the Skyrme energy-density functional (EDF). The aim is to find new phenomenological terms which are sensitive to experimental data. In this context we have extended the Skyrme functional by including terms which contain higher orders of derivatives allowing for a better description of finite range effects. This was done by employing an expansion in derivatives in a spherical-tensor formalism [1] motivated by ideas of the density-matrix expansion. The resulting functionals have different number of free parameters depending on the order in derivatives and assumed symmetries, see Fig. 1. The usual Skyrme EDF is obtained as a second order expansion while we keep terms up to sixth order.(author)
Cerebral energy metabolism and the brain's functional network architecture: an integrative review.
Lord, Louis-David; Expert, Paul; Huckins, Jeremy F; Turkheimer, Federico E
2013-09-01
Recent functional magnetic resonance imaging (fMRI) studies have emphasized the contributions of synchronized activity in distributed brain networks to cognitive processes in both health and disease. The brain's 'functional connectivity' is typically estimated from correlations in the activity time series of anatomically remote areas, and postulated to reflect information flow between neuronal populations. Although the topological properties of functional brain networks have been studied extensively, considerably less is known regarding the neurophysiological and biochemical factors underlying the temporal coordination of large neuronal ensembles. In this review, we highlight the critical contributions of high-frequency electrical oscillations in the γ-band (30 to 100 Hz) to the emergence of functional brain networks. After describing the neurobiological substrates of γ-band dynamics, we specifically discuss the elevated energy requirements of high-frequency neural oscillations, which represent a mechanistic link between the functional connectivity of brain regions and their respective metabolic demands. Experimental evidence is presented for the high oxygen and glucose consumption, and strong mitochondrial performance required to support rhythmic cortical activity in the γ-band. Finally, the implications of mitochondrial impairments and deficits in glucose metabolism for cognition and behavior are discussed in the context of neuropsychiatric and neurodegenerative syndromes characterized by large-scale changes in the organization of functional brain networks.
Comparison of experimental and theoretical binding and transition energies in the actinide region
International Nuclear Information System (INIS)
Krause, M.O.; Nestor, C.W. Jr.
1977-01-01
The status of experimental and theoretical binding and transition energy determinations is reviewed extending the comparison between experiment and theory to encompass representative series of data for all actinides. This comprehensive comparison reveals areas where improvements may be indicated, showing whether theoretical treatments including all known contributions to the lowest order would be adequate in all instances. 45 references
The role of dark energy in the evolution of the universe
CSIR Research Space (South Africa)
Greben, JM
2012-10-01
Full Text Available - expanding universe. In lowest order this expansion remains linear in the presence of matter and radiation, so that the proportions of dark energy and matter are not fixed strongly by the supernovae data and must be deduced from other astronomical data. One...
Effect of logarithmic terms on the energy level and wave function of a dtμ system
International Nuclear Information System (INIS)
Zhen, Z.
1990-01-01
The effect of the logarithmic terms on the ground-state energy level and wave function of a dtμ system is investigated. No significant contribution of the logarithmic terms on either the energy level or wave function is found. At the same time, we find the lowest upper bound of the ground-state energy ever obtained by the variational method using the Hylleraas-type trial function and that the corresponding wave function satisfies the cusp condition as r dt →0 automatically to a reasonable accuracy for r<3 (muonic a.u.), where r is the distance between the fused dt nuclear compound and the muon
Directory of Open Access Journals (Sweden)
B. A. Tonkonogov
2017-01-01
Full Text Available The aim of the work was the development of the original architecture of an integrated information system for analysis of the potential of renewable energy sources. The required functionality of system has led to the solution of a number of problems in the development of appropriate software modules that implement methods, models and algorithms for assessing the energy potential and economic efficiency of the use of renewable energy sources (RES. This required the solution of the following problems: adaptation of existing and development of new methods for analyzing the potential of RES at various territorial levels using modern technologies of geographic information systems and computer technologies were accomplished; models for the assessment and calculation of the potential of renewable energy resources were developed; techniques for assessing of the economic effectiveness of decisions made for using of RES were adapted; architecture of the information system was developed and the choice of technologies and means for its implementation was made; algorithms of software modules and their interaction as a parts of the information system were developed. A distinctive feature of the architecture were flexibility and openness for the expansion and implementation of additional functionality, in particular the development of special algorithms and software modules for interacting with the database and a graphical Web-based user interface that provides the ability to work with cartographic information. The development and implementation of this system is a modern up-to-date scientific and practical task, the solution of which will create conditions for increased use of RES in RB and improving the country’s energy security. The results of conducted researches and completed developments can be used in the system of the Ministry of Natural Resources and Environmental Protection of RB, in particular for maintaining of the state cadastre of RES and making
International Nuclear Information System (INIS)
Wang, H.; Zhou, P.; Zhou, D.Q.
2013-01-01
Improving energy efficiency and productivity is one of the most cost-effective ways for achieving the sustainable development target in China. This paper employs non-radial directional distance function approach to empirically investigate energy efficiency and energy productivity by including CO 2 emissions as an undesirable output. Three production scenarios, namely energy conservation (EC), energy conservation and emission reduction (ECER), and energy conservation, emission reduction and economic growth (ECEREG), are specified to assess China's energy efficiency and productivity growth during the period of Eleventh Five-Year Plan. Our empirical results show that there exist substantial differences in China's total-factor energy efficiency and productivity under different scenarios. Under the ECEREG scenario, the national average total-factor energy efficiency score was 0.6306 in 2005–2010, while the national average total-factor energy productivity increased by 0.27% annually during the period. The main driving force for energy productivity growth in China was energy technological change rather than energy efficiency change. - Highlights: • China's regional energy efficiency and productivity in 2005–2010 are evaluated. • Three production scenarios are considered. • Non-radial directional distance function with CO 2 emissions is employed. • Technological change is the main driver for China's energy productivity growth
Modern money theory and ecological tax reform: A functional finance approach to energy conservation
McConnell, Scott L. B.
This dissertation contributes to heterodox economics by developing a theoretical and policy-relevant link that will promote the conservation of energy while driving the value of the domestic currency. The analysis relies upon the theoretical foundation of modern money theory and functional finance, which states that "taxes-drive-money" where the value of a sovereign nation's currency is imputed through the acceptance by the sovereign nation of the currency in payment of taxation. This theoretical perspective lends itself to various public policy prescriptions, such as government employment policies or the employer of last resort (ELR), which has been discussed at length elsewhere (Wray 1998; Tcherneva 2007, Forstater 2003). This research contributes to this overall program by arguing that the basis for taxation under modern money theory allows public policy makers various alternatives regarding the make-up of the tax system in place. In particular, following functional finance, taxes do not have the sole purpose of paying for government spending, but rather drive the value of the currency and may be designed to perform other functions as well, such as penalizing socially undesirable behavior. The focus in this dissertation is on the amelioration of pollution and increasing energy conservation. The research question for this dissertation is this: what federally implemented tax would best serve the multiple criteria of 1) driving the value of the currency, 2) promoting energy conservation and 3) ameliorating income and wealth disparities inherent in a monetary production economy? This dissertation provides a suggestion for such a tax that would be part of a much larger overall policy program based upon the tenets of modern money theory and functional finance. Additionally, this research seeks to provide an important theoretical contribution to the emerging Post Keynesian and ecological economics dialog.
Studies of the energy density functional and its derivatives in atomic and molecular systems
International Nuclear Information System (INIS)
Robles, J.
1986-01-01
The first chapter is a review of formal density functional theory, (DFT). In the second chapter, approximations to exact DFT are reviewed. In chapter three, the author proposes a modified molecular Thomas-Fermi, (TF) theory. He proceeds by imposing a continuity condition on the density. This avoids the singularities at the nuclei of classical TF. The method is sanctioned by Teller and Balasz theorems. However, it is found that while the classical TF theory is improved, the present method still predicts no-binding. In chapter four, it is suggested that the correlation energy, (E/sub c/), is proportional to the exchange energy, (K), E/sub c/ = cK. This idea is tested with Hartree-Fock (HF) and DFT data. In HF, c = 1/40 for atoms and c = 1/25 for molecules. Furthermore, the method is used to estimate dissociation energies. Thereafter, the author studies the chemical potential, (μ), of atoms (chapter five) and molecules (chapter six). In chapter seven, the concept of local pressure in an inhomogeneous electronic system is studied and extended, within the local thermodynamic formulation of DFT. Finally, appendix A provides the required mathematical framework (basic functional calculus) to understand this work, while appendix B is essentially a summary of the HF method
Density Functional Methods for Shock Physics and High Energy Density Science
Desjarlais, Michael
2017-06-01
Molecular dynamics with density functional theory has emerged over the last two decades as a powerful and accurate framework for calculating thermodynamic and transport properties with broad application to dynamic compression, high energy density science, and warm dense matter. These calculations have been extensively validated against shock and ramp wave experiments, are a principal component of high-fidelity equation of state generation, and are having wide-ranging impacts on inertial confinement fusion, planetary science, and shock physics research. In addition to thermodynamic properties, phase boundaries, and the equation of state, one also has access to electrical conductivity, thermal conductivity, and lower energy optical properties. Importantly, all these properties are obtained within the same theoretical framework and are manifestly consistent. In this talk I will give a brief history and overview of molecular dynamics with density functional theory and its use in calculating a wide variety of thermodynamic and transport properties for materials ranging from ambient to extreme conditions and with comparisons to experimental data. I will also discuss some of the limitations and difficulties, as well as active research areas. Sandia is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.
Alekseev, S. A.; Dmitriev, A. S.; Dmitriev, A. A.; Makarov, P. G.; Mikhailova, I. A.
2017-11-01
In recent years, there has been a great interest in the development and creation of new functional energy materials, including for improving the energy efficiency of power equipment and for effectively removing heat from energy devices, microelectronics and optoelectronics (power micro electronics, supercapacitors, cooling of processors, servers and Data centers). In this paper, the technology of obtaining a new nanocomposite based on mesoscopic microspheres, polymers and graphene flakes is considered. The methods of sequential production of functional materials from graphite flakes of different volumetric concentration using polymers based on epoxy resins and polyimide, as well as the addition of a mesoscopic medium in the form of monodisperse microspheres are described. The data of optical and electron microscopy of such nanocomposites are presented, the main problems in the appearance of defects in such materials are described, the possibilities of their elimination by the selection of different concentrations and sizes of the components. Data are given on the measurement of the hysteresis of the contact angle and the evaporation of droplets on similar substrates. The results of studying the mechanical, electrophysical and thermal properties of such nanocomposites are presented. Particular attention is paid to the investigation of the thermal conductivity of these nanocomposites with respect to the creation of thermal interface materials for cooling devices of electronics, optoelectronics and power engineering.
Husowitz, B; Talanquer, V
2007-02-07
Density functional theory is used to explore the solvation properties of a spherical solute immersed in a supercritical diatomic fluid. The solute is modeled as a hard core Yukawa particle surrounded by a diatomic Lennard-Jones fluid represented by two fused tangent spheres using an interaction site approximation. The authors' approach is particularly suitable for thoroughly exploring the effect of different interaction parameters, such as solute-solvent interaction strength and range, solvent-solvent long-range interactions, and particle size, on the local solvent structure and the solvation free energy under supercritical conditions. Their results indicate that the behavior of the local coordination number in homonuclear diatomic fluids follows trends similar to those reported in previous studies for monatomic fluids. The local density augmentation is particularly sensitive to changes in solute size and is affected to a lesser degree by variations in the solute-solvent interaction strength and range. The associated solvation free energies exhibit a nonmonotonous behavior as a function of density for systems with weak solute-solvent interactions. The authors' results suggest that solute-solvent interaction anisotropies have a major influence on the nature and extent of local solvent density inhomogeneities and on the value of the solvation free energies in supercritical solutions of heteronuclear molecules.
DOE Energy Frontiers Research Center for Heterogeneous Functional Materials; the “HeteroFoaM Center”
Energy Technology Data Exchange (ETDEWEB)
Reifsnider, Kenneth Leonard [Univ. of South Carolina, Columbia, SC (United States)
2016-11-03
Synopsis of five year accomplishments: Devices that convert and store energy are generally made from heterogeneous constituent materials that act and interact to selectively conduct, transport, and separate mass, heat, and charge. Controlling these actions and interactions enables the technical breakthroughs that have made fuel cells, batteries, and solid state membranes, for example, essential parts of our society. In the biological sense, these materials are ‘vascular’ rather than primitive ‘cellular’ materials, in which the arrangements and configurations of the constituents (including their void phases) play essential and definitive roles in their functional capabilities. In 2009 a group of investigators, with lifetime investments of effort in the understanding of heterogeneous materials, recognized that the design of such material systems is not an optimization problem as such. Local interactions of the constituents create “emergent” properties and responses that are not part of the formal set of constituent characteristics, in much the same sense that society and culture is created by the group interactions of the people involved. The design of emergent properties is an open question in all formal science, but for energy materials the lack of this foundation science relegates development tasks to Edisonian trial and error, with anecdotal success and frequent costly failures. That group defined, for the first time, multi-scale heterogeneous functional materials with functional disordered and void phase regions as “HeteroFoaM,” and formed the first multidisciplinary research team to define and codify the foundation science of that material class. The primary goal of the HeteroFoaM Center was, and is, to create and establish the multi-scale fundamental knowledge and related methodology required for the rational and systematic multiphysics design of heterogeneous functional materials and their interfaces and surfaces for applications in energy
International Nuclear Information System (INIS)
Lee, Sang Uck
2013-01-01
The accurate prediction of vertical excitation energies is very important for the development of new materials in the dye and pigment industry. A time-dependent density functional theory (TD-DFT) approach coupled with 22 different exchange-correlation functionals was used for the prediction of vertical excitation energies in the halogenated copper phthalocyanine molecules in order to find the most appropriate functional and to determine the accuracy of the prediction of the absorption wavelength and observed spectral shifts. Among the tested functional, B3LYP functional provides much more accurate vertical excitation energies and UV-vis spectra. Our results clearly provide a benchmark calibration of the TD-DFT method for phthalocyanine based dyes and pigments used in industry
Statistical measurement of the gamma-ray source-count distribution as a function of energy
Zechlin, H.-S.; Cuoco, A.; Donato, F.; Fornengo, N.; Regis, M.
2017-01-01
Photon counts statistics have recently been proven to provide a sensitive observable for characterizing gamma-ray source populations and for measuring the composition of the gamma-ray sky. In this work, we generalize the use of the standard 1-point probability distribution function (1pPDF) to decompose the high-latitude gamma-ray emission observed with Fermi-LAT into: (i) point-source contributions, (ii) the Galactic foreground contribution, and (iii) a diffuse isotropic background contribution. We analyze gamma-ray data in five adjacent energy bands between 1 and 171 GeV. We measure the source-count distribution dN/dS as a function of energy, and demonstrate that our results extend current measurements from source catalogs to the regime of so far undetected sources. Our method improves the sensitivity for resolving point-source populations by about one order of magnitude in flux. The dN/dS distribution as a function of flux is found to be compatible with a broken power law. We derive upper limits on further possible breaks as well as the angular power of unresolved sources. We discuss the composition of the gamma-ray sky and capabilities of the 1pPDF method.
Nuclear energy density functional from chiral pion-nucleon dynamics revisited
Kaiser, N.; Weise, W.
2010-05-01
We use a recently improved density-matrix expansion to calculate the nuclear energy density functional in the framework of in-medium chiral perturbation theory. Our calculation treats systematically the effects from 1 π-exchange, iterated 1 π-exchange, and irreducible 2 π-exchange with intermediate Δ-isobar excitations, including Pauli-blocking corrections up to three-loop order. We find that the effective nucleon mass M(ρ) entering the energy density functional is identical to the one of Fermi-liquid theory when employing the improved density-matrix expansion. The strength F(ρ) of the ( surface-term as provided by the pion-exchange dynamics is in good agreement with that of phenomenological Skyrme forces in the density region ρ/2short-range spin-orbit interaction. The strength function F(ρ) multiplying the square of the spin-orbit density comes out much larger than in phenomenological Skyrme forces and it has a pronounced density dependence.
DART: A Functional-Level Reconfigurable Architecture for High Energy Efficiency
Directory of Open Access Journals (Sweden)
Sébastien Pillement
2007-12-01
Full Text Available Flexibility becomes a major concern for the development of multimedia and mobile communication systems, as well as classical high-performance and low-energy consumption constraints. The use of general-purpose processors solves flexibility problems but fails to cope with the increasing demand for energy efficiency. This paper presents the DART architecture based on the functional-level reconfiguration paradigm which allows a significant improvement in energy efficiency. DART is built around a hierarchical interconnection network allowing high flexibility while keeping the power overhead low. To enable specific optimizations, DART supports two modes of reconfiguration. The compilation framework is built using compilation and high-level synthesis techniques. A 3G mobile communication application has been implemented as a proof of concept. The energy distribution within the architecture and the physical implementation are also discussed. Finally, the VLSI design of a 0.13Ã¢Â€Â‰ÃŽÂ¼m CMOS SoC implementing a specialized DART cluster is presented.
Keshavarzi, Ezat; Kamalvand, Mohammad
2009-04-23
The structure and properties of fluids confined in nanopores may show a dramatic departure from macroscopic bulk fluids. The main reason for this difference lies in the influence of system walls. In addition to the entropic wall effect, system walls can significantly change the energy of the confined fluid compared to macroscopic bulk fluids. The energy effect of the walls on a nanoconfined fluid appears in two forms. The first effect is the cutting off of the intermolecular interactions by the walls, which appears for example in the integrals for calculation of the thermodynamic properties. The second wall effect involves the wall-molecule interactions. In such confined fluids, the introduction of wall forces and the competition between fluid-wall and fluid-fluid forces could lead to interesting thermodynamic properties, including new kinds of phase transitions not observed in the macroscopic fluid systems. In this article, we use the perturbative fundamental measure density functional theory to study energy effects on the structure and properties of a hard core two-Yukawa fluid confined in a nanoslit. Our results show the changes undergone by the structure and phase transition of the nanoconfined fluids as a result of energy effects.
Squeeze-out of nuclear matter as a function of projectile energy and mass
International Nuclear Information System (INIS)
Gutbrod, H.H.; Kampert, K.H.; Kolb, B.; Poskanzer, A.M.; Ritter, H.G.; Schicker, R.; Schmidt, H.R.
1990-01-01
Squeeze-out, a component of the collective flow of nuclear matter, is the preferential emission of particles out of the reaction plane. Using the sphericity method the out-of-plane/in-plane ratio of the kinetic energy flow has been analyzed as a function of multiplicity and beam energy for Ca+Ca, Nb+Nb, and Au+Au collisions measured with the Plastic Ball detector at the Bevalac. Also, azimuthal distribution of the particles around the flow axis are presented together with the extracted out-of-plane/in-plane ratios. Finally, the rapidity dependence of the out-of-plane/in-plane ratio has been investigated with a new method using the transverse momentum components of the particles
LDRD final report : energy conversion using chromophore-functionalized carbon nanotubes.
Energy Technology Data Exchange (ETDEWEB)
Vance, Andrew L.; Zifer, Thomas; Zhou, Xinjian; Leonard, Francois Leonard; Wong, Bryan Matthew; Kane, Alexander; Katzenmeyer, Aaron Michael; Krafcik, Karen Lee
2010-09-01
With the goal of studying the conversion of optical energy to electrical energy at the nanoscale, we developed and tested devices based on single-walled carbon nanotubes functionalized with azobenzene chromophores, where the chromophores serve as photoabsorbers and the nanotube as the electronic read-out. By synthesizing chromophores with specific absorption windows in the visible spectrum and anchoring them to the nanotube surface, we demonstrated the controlled detection of visible light of low intensity in narrow ranges of wavelengths. Our measurements suggested that upon photoabsorption, the chromophores isomerize to give a large change in dipole moment, changing the electrostatic environment of the nanotube. All-electron ab initio calculations were used to study the chromophore-nanotube hybrids, and show that the chromophores bind strongly to the nanotubes without disturbing the electronic structure of either species. Calculated values of the dipole moments supported the notion of dipole changes as the optical detection mechanism.
Evaluating C-RAN Fronthaul Functional Splits in Terms of Network Level Energy and Cost Savings
DEFF Research Database (Denmark)
Checko, Aleksandra; Popovska Avramova, Andrijana; Berger, Michael Stübert
2016-01-01
The placement of the complete baseband processing in a centralized pool results in high data rate requirement and inflexibility of the fronthaul network, which challenges the energy and cost effectiveness of the cloud radio access network (C-RAN). Recently, redesign of the C-RAN through functional...... split in the baseband processing chain has been proposed to overcome these challenges. This paper evaluates, by mathematical and simulation methods, different splits with respect to network level energy and cost efficiency having in the mind the expected quality of service.The proposed mathematical...... model quantifies the multiplexing gains and the trade-offs between centralization and decentralization concerning the cost of the pool, fronthaul network capacity and resource utilization. The event-based simulation captures the influence of the traffic load dynamics and traffic type variation...
Energy Technology Data Exchange (ETDEWEB)
Dodt, Dirk Hilar
2009-01-05
The experimental determination of the electron energy distribution of a low pressure glow discharge in neon from emission spectroscopic data has been demonstrated. The spectral data were obtained with a simple overview spectrometer and analyzed using a strict probabilistic, Bayesian data analysis. It is this Integrated Data Analysis (IDA) approach, which allows the significant extraction of non-thermal properties of the electron energy distribution function (EEDF). The results bear potential as a non-invasive alternative to probe measurements. This allows the investigation of spatially inhomogeneous plasmas (gradient length smaller than typical probe sheath dimensions) and plasmas with reactive constituents. The diagnostic of reactive plasmas is an important practical application, needed e.g. for the monitoring and control of process plasmas. Moreover, the experimental validation of probe theories for magnetized plasmas as a long-standing topic in plasma diagnostics could be addressed by the spectroscopic method. (orig.)
Energy Technology Data Exchange (ETDEWEB)
Jaworski, M A; Gray, T K; Kaita, R; Kallman, J; Kugel, H; LeBlanc, B; McLean, A; Sabbagh, S A; Soukanovskii, V; Stotler, D P
2011-06-03
The National Spherical Torus Experiment (NSTX) has recently studied the use of a liquid lithium divertor (LLD). Divertor Langmuir probes have also been installed for making measurements of the local plasma conditions. A non-local probe interpretation method is used to supplement the classical probe interpretation and obtain measurements of the electron energy distribution function (EEDF) which show the occurrence of a hot-electron component. Analysis is made of two discharges within a sequence that exhibited changes in plasma fueling efficiency. It is found that the local electron temperature increases and that this increase is most strongly correlated with the energy contained within the hot-electron population. Preliminary interpretative modeling indicates that kinetic effects are likely in the NSTX.
Energy Technology Data Exchange (ETDEWEB)
Zamanian, Amir Hosein [Southern Methodist University, Dallas (United States); Ohadi, Abdolreza [Amirkabir University of Technology (Tehran Polytechnic), Tehran (Iran, Islamic Republic of)
2017-06-15
Low-dimensional relevant feature sets are ideal to avoid extra data mining for classification. The current work investigates the feasibility of utilizing energies of vibration signals in optimal frequency bands as features for machine fault diagnosis application. Energies in different frequency bands were derived based on Parseval's theorem. The optimal feature sets were extracted by optimization of the related frequency bands using genetic algorithm and a Modified distance function (MDF). The frequency bands and the number of bands were optimized based on the MDF. The MDF is designed to a) maximize the distance between centers of classes, b) minimize the dispersion of features in each class separately, and c) minimize dimension of extracted feature sets. The experimental signals in two different gearboxes were used to demonstrate the efficiency of the presented technique. The results show the effectiveness of the presented technique in gear fault diagnosis application.
International Nuclear Information System (INIS)
Dodt, Dirk Hilar
2009-01-01
The experimental determination of the electron energy distribution of a low pressure glow discharge in neon from emission spectroscopic data has been demonstrated. The spectral data were obtained with a simple overview spectrometer and analyzed using a strict probabilistic, Bayesian data analysis. It is this Integrated Data Analysis (IDA) approach, which allows the significant extraction of non-thermal properties of the electron energy distribution function (EEDF). The results bear potential as a non-invasive alternative to probe measurements. This allows the investigation of spatially inhomogeneous plasmas (gradient length smaller than typical probe sheath dimensions) and plasmas with reactive constituents. The diagnostic of reactive plasmas is an important practical application, needed e.g. for the monitoring and control of process plasmas. Moreover, the experimental validation of probe theories for magnetized plasmas as a long-standing topic in plasma diagnostics could be addressed by the spectroscopic method. (orig.)
Excitation function of elastic scattering on 12C + 4He system, at low energies
International Nuclear Information System (INIS)
Perez-Torres, R.; Aguilera, E. F.; Martinez-Quiroz, E.; Murillo, G.; Belyaeva, T. L.; Maldonado-Velazquez, M.
2011-01-01
Interactions in the 12 C + 4 He system are of great interest in astrophysics and to help determine the relative abundances of elements in stars, at the end of helium burning [1, 2]. The Instituto Nacional de Investigaciones Nucleares (ININ) in Mexico, have made measurements of elastic scattering for this system, using the inverse kinematics method with thick white gas [3, 4], for E CM (0.5 - 4 MeV) θ CM = 180 o . In this work we obtain excitation functions of elastic scattering of 12 C + 4 He system with angular and energy dependence; E CM = 0.5 - 4 MeV and θ CM 100 o -170 o .Using inverse kinematics method with thick white gas and energy loss tables. (Author)
“Multi-functional Agriculture - Agriculture as a Resource for Energy and Environmental Preservation
Directory of Open Access Journals (Sweden)
the Editors
2008-10-01
Full Text Available In the present global situation, agriculture plays a major role in the interaction between socio-economic and biophysical processes. In addition to its principal and fundamental role of providing food, it now also needs to consider other ecosystem services provided by agriculture and to explore the new frontiers for the the future. In the 50’s of the 20th century the major topic was the introduction of inorganic fertilizers, in the 60’s the use of synthetic compounds for plant protection (insecticides, herbicides, fungicides, in the 70’s industrial crops, in the 80’s organic farming and the environmental impact of agronomic practices, and in the 90’s genetically modified crops (herbicide tolerance, insect resistance. In the current decade the themes are: land and water degradation, the production of agricultural biomass for bio-energy, and the increased expression of functional compounds in crops. The Bologna X Congress of ESA “Multi-functional Agriculture - Agriculture as a Resource for Energy and Environmental Preservation”, will meet the needs of finding tools to deal with environmental problems coupled with the increasing demand for food, and filling the knowledge gap on the physiological relationships between functional compound bio-synthesis and agricultural practices. Members of the European Society for Agronomy already have a deep knowledge of these issues, and the Bologna ESA Congress will provide an opportunity to develop them further particularly in regard to innovative agricultural techniques, new energy sources and better environmental monitoring.
International Nuclear Information System (INIS)
Vazquez, A.; Iglesias, G.
2016-01-01
Highlights: • A method for selecting the most suitable sites for tidal stream farms was presented. • The selection was based on relevant technical, economic and functional aspects. • As a case study, a model of the Bristol Channel was implemented and validated. - Abstract: Although a number of prospective locations for tidal stream farms have been identified, the development of a unified approach for selecting the optimum site in a region remains a current research topic. The objective of this work is to develop and apply a methodology for determining the most suitable sites for tidal stream farms, i.e. sites whose characteristics maximise power performance, minimise cost and avoid conflicts with competing uses of the marine space. Illustrated through a case study in the Bristol Channel, the method uses a validated hydrodynamics model to identify highly energetic areas and a geospatial Matlab-based program (designed ad hoc) to estimate the energy output that a tidal farm at the site with a given technology would have. This output is then used to obtain the spatial distribution of the levelised cost of energy and, on this basis, to preselect certain areas. Subsequently, potential conflicts with other functions of the marine space (e.g. fishing, shipping) are considered. The result is a selection of areas for tidal stream energy development based on a holistic approach, encompassing the relevant technical, economic and functional aspects. This methodology can lead to a significant improvement in the selection of tidal sites, thereby increasing the possibilities of project acceptance and development.
The tensor part of the Skyrme energy density functional. I. Spherical nuclei
Energy Technology Data Exchange (ETDEWEB)
Lesinski, T.; Meyer, J. [Universite de Lyon, F-69003 Lyon (France)]|[Institut de Physique Nucleaire de Lyon, CNRS/IN2P3, Universite Lyon 1, F-69622 Villeurbanne (France); Bender, M. [DSM/DAPNIA/SPhN, CEA Saclay, F-91191 Gif-sur-Yvette Cedex (France)]|[Universite Bordeaux, CNRS/IN2P3, Centre d' Etudes Nucleaires de Bordeaux Gradignan, UMR5797, Chemin du Solarium, BP120, F-33175 Gradignan (France); Bennaceur, K. [Universite de Lyon, F-69003 Lyon (France)]|[Institut de Physique Nucleaire de Lyon, CNRS/IN2P3, Universite Lyon 1, F-69622 Villeurbanne (France)]|[DSM/DAPNIA/SPhN, CEA Saclay, F-91191 Gif-sur-Yvette Cedex (France); Duguet, T. [National Superconducting Cyclotron Laboratory and Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 (United States)
2007-04-15
We perform a systematic study of the impact of the J-vector{sup 2} tensor term in the Skyrme energy functional on properties of spherical nuclei. In the Skyrme energy functional, the tensor terms originate both from zero-range central and tensor forces. We build a set of 36 parameterizations which cover a wide range of the parameter space of the isoscalar and isovector tensor term coupling constants with a fit protocol very similar to that of the successful SLy parameterizations. We analyze the impact of the tensor terms on a large variety of observables in spherical mean-field calculations, such as the spin-orbit splittings and single-particle spectra of doubly-magic nuclei, the evolution of spin-orbit splittings along chains of semi-magic nuclei, mass residuals of spherical nuclei, and known anomalies of radii. The major findings of our study are (i) tensor terms should not be added perturbatively to existing parameterizations, a complete refit of the entire parameter set is imperative. (ii) The free variation of the tensor terms does not lower the {chi}{sup 2} within a standard Skyrme energy functional. (iii) For certain regions of the parameter space of their coupling constants, the tensor terms lead to instabilities of the spherical shell structure, or even the coexistence of two configurations with different spherical shell structure. (iv) The standard spin-orbit interaction does not scale properly with the principal quantum number, such that single-particle states with one or several nodes have too large spin-orbit splittings, while those of node-less intruder levels are tentatively too small. Tensor terms with realistic coupling constants cannot cure this problem. (v) Positive values of the coupling constants of proton-neutron and like-particle tensor terms allow for a qualitative description of the evolution of spin-orbit splittings in chains of Ca, Ni and Sn isotopes. (vi) For the same values of the tensor term coupling constants, however, the overall
Electron energy distribution function in a cathode fall region of DC-glow discharge
International Nuclear Information System (INIS)
Elakshar, F.F.; Garamoon, A.A.; Hassouba, M.A.
1997-01-01
Recently a substantial effort has been devoted towards the development of a quantitative microscopic measurements in the cathode fall region of the DC-glow discharge magnetron sputtering unit. The electron energy distribution function (EEDF) has been measured using a single Langmuir probe at the edge of the cathode fall. Two groups of electrons are observed in helium and argon gas discharges. The two groups have no chance to be thermalized since they leave the cathode fall region fast. The electron temperature measurements have been compared with spectroscopic determination. Plasma density has been computed and compared with probe measurements. Sources of the two groups of electrons are also discussed. (author)
Skeleton series and multivaluedness of the self-energy functional in zero space-time dimensions
Rossi, Riccardo; Werner, Félix
2015-12-01
Recently, Kozik, Ferrero and Georges discovered numerically that for a family of fundamental models of interacting fermions, the self-energy {{Σ }}[G] is a multi-valued functional of the fully dressed single-particle propagator G, and that the skeleton diagrammatic series {{{Σ }}}{{bold}}[G] converges to the wrong branch above a critical interaction strength. We consider the zero space-time dimensional case, where the same mathematical phenomena appear from elementary algebra. We also find a similar phenomenology for the fully bold formalism built on the fully dressed single-particle propagator and pair propagator.
DEFF Research Database (Denmark)
Zhang, Minwei; Hou, Chengyi; Halder, Arnab
2017-01-01
for their critical applications associated with sensing, environmental and energy technologies. The contents of this review are based on a balance combination of our own studies and selected research studies done by worldwide academic groups. We first give a brief introduction to graphene as a versatile building...... block and to the current status of research studies on graphene papers. This is followed by addressing some crucial methods of how to prepare graphene papers. We then summarize multiple possibilities of functionalizing graphene papers, membranes or films. Finally, we evaluate some key applications...
Accurate core-electron binding energy shifts from density functional theory
International Nuclear Information System (INIS)
Takahata, Yuji; Marques, Alberto Dos Santos
2010-01-01
Current review covers description of density functional methods of calculation of accurate core-electron binding energy (CEBE) of second and third row atoms; applications of calculated CEBEs and CEBE shifts (ΔCEBEs) in elucidation of topics such as: hydrogen-bonding, peptide bond, polymers, DNA bases, Hammett substituent (σ) constants, inductive and resonance effects, quantitative structure activity relationship (QSAR), and solid state effect (WD). This review limits itself to works of mainly Chong and his coworkers for the period post-2002. It is not a fully comprehensive account of the current state of the art.
Directory of Open Access Journals (Sweden)
Diana E. Proffit
2010-11-01
Full Text Available Doping limits, band gaps, work functions and energy band alignments of undoped and donor-doped transparent conducting oxides Zn0, In2O3, and SnO2 as accessed by X-ray and ultraviolet photoelectron spectroscopy (XPS/UPS are summarized and compared. The presented collection provides an extensive data set of technologically relevant electronic properties of photovoltaic transparent electrode materials and illustrates how these relate to the underlying defect chemistry, the dependence of surface dipoles on crystallographic orientation and/or surface termination, and Fermi level pinning.
Directory of Open Access Journals (Sweden)
Sarah Sonnay
2017-05-01
Full Text Available Cerebral function is associated with exceptionally high metabolic activity, and requires continuous supply of oxygen and nutrients from the blood stream. Since the mid-twentieth century the idea that brain energy metabolism is coupled to neuronal activity has emerged, and a number of studies supported this hypothesis. Moreover, brain energy metabolism was demonstrated to be compartmentalized in neurons and astrocytes, and astrocytic glycolysis was proposed to serve the energetic demands of glutamatergic activity. Shedding light on the role of astrocytes in brain metabolism, the earlier picture of astrocytes being restricted to a scaffold-associated function in the brain is now out of date. With the development and optimization of non-invasive techniques, such as nuclear magnetic resonance spectroscopy (MRS, several groups have worked on assessing cerebral metabolism in vivo. In this context, 1H MRS has allowed the measurements of energy metabolism-related compounds, whose concentrations can vary under different brain activation states. 1H-[13C] MRS, i.e., indirect detection of signals from 13C-coupled 1H, together with infusion of 13C-enriched glucose has provided insights into the coupling between neurotransmission and glucose oxidation. Although these techniques tackle the coupling between neuronal activity and metabolism, they lack chemical specificity and fail in providing information on neuronal and glial metabolic pathways underlying those processes. Currently, the improvement of detection modalities (i.e., direct detection of 13C isotopomers, the progress in building adequate mathematical models along with the increase in magnetic field strength now available render possible detailed compartmentalized metabolic flux characterization. In particular, direct 13C MRS offers more detailed dataset acquisitions and provides information on metabolic interactions between neurons and astrocytes, and their role in supporting neurotransmission. Here
van Aggelen, Helen; Yang, Yang; Yang, Weitao
2014-05-14
Despite their unmatched success for many applications, commonly used local, semi-local, and hybrid density functionals still face challenges when it comes to describing long-range interactions, static correlation, and electron delocalization. Density functionals of both the occupied and virtual orbitals are able to address these problems. The particle-hole (ph-) Random Phase Approximation (RPA), a functional of occupied and virtual orbitals, has recently known a revival within the density functional theory community. Following up on an idea introduced in our recent communication [H. van Aggelen, Y. Yang, and W. Yang, Phys. Rev. A 88, 030501 (2013)], we formulate more general adiabatic connections for the correlation energy in terms of pairing matrix fluctuations described by the particle-particle (pp-) propagator. With numerical examples of the pp-RPA, the lowest-order approximation to the pp-propagator, we illustrate the potential of density functional approximations based on pairing matrix fluctuations. The pp-RPA is size-extensive, self-interaction free, fully anti-symmetric, describes the strong static correlation limit in H2, and eliminates delocalization errors in H2(+) and other single-bond systems. It gives surprisingly good non-bonded interaction energies--competitive with the ph-RPA--with the correct R(-6) asymptotic decay as a function of the separation R, which we argue is mainly attributable to its correct second-order energy term. While the pp-RPA tends to underestimate absolute correlation energies, it gives good relative energies: much better atomization energies than the ph-RPA, as it has no tendency to underbind, and reaction energies of similar quality. The adiabatic connection in terms of pairing matrix fluctuation paves the way for promising new density functional approximations.
International Nuclear Information System (INIS)
Aggelen, Helen van; Yang, Yang; Yang, Weitao
2014-01-01
Despite their unmatched success for many applications, commonly used local, semi-local, and hybrid density functionals still face challenges when it comes to describing long-range interactions, static correlation, and electron delocalization. Density functionals of both the occupied and virtual orbitals are able to address these problems. The particle-hole (ph-) Random Phase Approximation (RPA), a functional of occupied and virtual orbitals, has recently known a revival within the density functional theory community. Following up on an idea introduced in our recent communication [H. van Aggelen, Y. Yang, and W. Yang, Phys. Rev. A 88, 030501 (2013)], we formulate more general adiabatic connections for the correlation energy in terms of pairing matrix fluctuations described by the particle-particle (pp-) propagator. With numerical examples of the pp-RPA, the lowest-order approximation to the pp-propagator, we illustrate the potential of density functional approximations based on pairing matrix fluctuations. The pp-RPA is size-extensive, self-interaction free, fully anti-symmetric, describes the strong static correlation limit in H 2 , and eliminates delocalization errors in H 2 + and other single-bond systems. It gives surprisingly good non-bonded interaction energies – competitive with the ph-RPA – with the correct R −6 asymptotic decay as a function of the separation R, which we argue is mainly attributable to its correct second-order energy term. While the pp-RPA tends to underestimate absolute correlation energies, it gives good relative energies: much better atomization energies than the ph-RPA, as it has no tendency to underbind, and reaction energies of similar quality. The adiabatic connection in terms of pairing matrix fluctuation paves the way for promising new density functional approximations
Characterization of the dose perturbation in tissue by stents as a function of external beam energy
International Nuclear Information System (INIS)
Schell, M.C.; Rosenzweig, D.P.; Weaver, K.A.; Rubin, P.
1997-01-01
Purpose: External beam irradiation of coronary arteries was shown to be detrimental in an animal model for the prevention of neointimal hyperplasia in the presence of stents when orthovoltage x-ray beams are used. This present study investigated the effect of beam energy on the dose distribution in the wall of the artery as a function of energy in the presence of stents in order to ascertain the effect on the dose due to beam energy. Materials and Methods: 250 kVp x-rays and 6-MV x rays were used to irradiate a stent placed in an homogeneous phantom. Radiochromic film densitometry and Monte Carlo calculations were used to measure and to simulate the dose distribution in the proximity of the stent. Result: External beam irradiation was reported to not only fail to prevent neointimal hyperplasia, but actually accentuate the neointimal response to a prompt mechanical injury in the artery. The photoelectric effect, which dominates low-energy x-ray interactions, produces recoil electrons in the stent which enhance the dose surrounding intima. The photoelectrons generated in nickel and iron have an extremely short range in normal tissue, approximately 0.1 mm. Initial estimates of orthovoltage x-ray interactions with the stent indicate a dose enhancement in the orthovoltage range by a factor of 2 to 3 due to the rise in the photoelectric cross section in this energy range depending on the elemental composition of the stent. Film densitometry verifies this dose enhancement. The Monte Carlo calculations yield a dose enhancement and the dose fall off with distance from the stent when irradiated with orthovoltage x-rays. Conversely when the tissue and stent are irradiated with megavoltage x-rays, the dose enhancement in this region is a factor of 1.15 in close proximity to the stent and 1.0 at distances greater than 0.1 mm. 6-MV photon interactions in tissue and iron are predominantly through Compton scattering. The Compton effect is dependent on the electron density in the
Kroonblawd, Matthew; Goldman, Nir
First principles molecular dynamics using highly accurate density functional theory (DFT) is a common tool for predicting chemistry, but the accessible time and space scales are often orders of magnitude beyond the resolution of experiments. Semi-empirical methods such as density functional tight binding (DFTB) offer up to a thousand-fold reduction in required CPU hours and can approach experimental scales. However, standard DFTB parameter sets lack good transferability and calibration for a particular system is usually necessary. Force matching the pairwise repulsive energy term in DFTB to short DFT trajectories can improve the former's accuracy for chemistry that is fast relative to DFT simulation times (Contract DE-AC52-07NA27344.
Kroonblawd, Matthew; Goldman, Nir
2017-06-01
First principles molecular dynamics using highly accurate density functional theory (DFT) is a common tool for predicting chemistry, but the accessible time and space scales are often orders of magnitude beyond the resolution of experiments. Semi-empirical methods such as density functional tight binding (DFTB) offer up to a thousand-fold reduction in required CPU hours and can approach experimental scales. However, standard DFTB parameter sets lack good transferability and calibration for a particular system is usually necessary. Force matching the pairwise repulsive energy term in DFTB to short DFT trajectories can improve the former's accuracy for reactions that are fast relative to DFT simulation times (Contract DE-AC52-07NA27344.
Brandenburg, Jan Gerit; Caldeweyher, Eike; Grimme, Stefan
2016-06-21
We extend the recently introduced PBEh-3c global hybrid density functional [S. Grimme et al., J. Chem. Phys., 2015, 143, 054107] by a screened Fock exchange variant based on the Henderson-Janesko-Scuseria exchange hole model. While the excellent performance of the global hybrid is maintained for small covalently bound molecules, its performance for computed condensed phase mass densities is further improved. Most importantly, a speed up of 30 to 50% can be achieved and especially for small orbital energy gap cases, the method is numerically much more robust. The latter point is important for many applications, e.g., for metal-organic frameworks, organic semiconductors, or protein structures. This enables an accurate density functional based electronic structure calculation of a full DNA helix structure on a single core desktop computer which is presented as an example in addition to comprehensive benchmark results.
Calculation of Multisphere Neutron Spectrometer Response Functions in Energy Range up to 20 MeV
Martinkovic, J
2005-01-01
Multisphere neutron spectrometer is a basic instrument of neutron measurements in the scattered radiation field at charged-particles accelerators for radiation protection and dosimetry purposes. The precise calculation of the spectrometer response functions is a necessary condition of the propriety of neutron spectra unfolding. The results of the response functions calculation for the JINR spectrometer with LiI(Eu) detector (a set of 6 homogeneous and 1 heterogeneous moderators, "bare" detector within cadmium cover and without it) at two geometries of the spectrometer irradiation - in uniform monodirectional and uniform isotropic neutron fields - are given. The calculation was carried out by the code MCNP in the neutron energy range 10$^{-8}$-20 MeV.
Shi, Yuguang; Cheng, Dong
2009-07-01
Monoacyglycerol acyltransferases (MGATs) and diacylglycerol acyltransferases (DGATs) catalyze two consecutive steps of enzyme reactions in the synthesis of triacylglycerols (TAGs). The metabolic complexity of TAG synthesis is reflected by the presence of multiple isoforms of MGAT and DGAT enzymes that differ in catalytic properties, subcellular localization, tissue distribution, and physiological functions. MGAT and DGAT enzymes play fundamental roles in the metabolism of monoacylglycerol (MAG), diacylglycerol (DAG), and triacylglycerol (TAG) that are involved in many aspects of physiological functions, such as intestinal fat absorption, lipoprotein assembly, adipose tissue formation, signal transduction, satiety, and lactation. The recent progress in the phenotypic characterization of mice deficient in MGAT and DGAT enzymes and the development of chemical inhibitors have revealed important roles of these enzymes in the regulation of energy homeostasis and insulin sensitivity. Consequently, selective inhibition of MGAT or DGAT enzymes by synthetic compounds may provide novel treatment for obesity and its related metabolic complications.
Multicomponent Time-Dependent Density Functional Theory: Proton and Electron Excitation Energies.
Yang, Yang; Culpitt, Tanner; Hammes-Schiffer, Sharon
2018-04-05
The quantum mechanical treatment of both electrons and protons in the calculation of excited state properties is critical for describing nonadiabatic processes such as photoinduced proton-coupled electron transfer. Multicomponent density functional theory enables the consistent quantum mechanical treatment of more than one type of particle and has been implemented previously for studying ground state molecular properties within the nuclear-electronic orbital (NEO) framework, where all electrons and specified protons are treated quantum mechanically. To enable the study of excited state molecular properties, herein the linear response multicomponent time-dependent density functional theory (TDDFT) is derived and implemented within the NEO framework. Initial applications to FHF - and HCN illustrate that NEO-TDDFT provides accurate proton and electron excitation energies within a single calculation. As its computational cost is similar to that of conventional electronic TDDFT, the NEO-TDDFT approach is promising for diverse applications, particularly nonadiabatic proton transfer reactions, which may exhibit mixed electron-proton vibronic excitations.
Quasi-particle energy spectra in local reduced density matrix functional theory.
Lathiotakis, Nektarios N; Helbig, Nicole; Rubio, Angel; Gidopoulos, Nikitas I
2014-10-28
Recently, we introduced [N. N. Lathiotakis, N. Helbig, A. Rubio, and N. I. Gidopoulos, Phys. Rev. A 90, 032511 (2014)] local reduced density matrix functional theory (local RDMFT), a theoretical scheme capable of incorporating static correlation effects in Kohn-Sham equations. Here, we apply local RDMFT to molecular systems of relatively large size, as a demonstration of its computational efficiency and its accuracy in predicting single-electron properties from the eigenvalue spectrum of the single-particle Hamiltonian with a local effective potential. We present encouraging results on the photoelectron spectrum of molecular systems and the relative stability of C20 isotopes. In addition, we propose a modelling of the fractional occupancies as functions of the orbital energies that further improves the efficiency of the method useful in applications to large systems and solids.
Functional materials for information and energy technology: Insights by photoelectron spectroscopy
International Nuclear Information System (INIS)
Müller, Martina; Nemšák, Slavomír; Plucinski, Lukasz; Schneider, Claus M.
2016-01-01
Highlights: • Photoemission spectro/microscopy studies of functional material systems. • Hard X-ray photoemission spectroscopy from magnetic semiconductors and insulators. • Information depth studies in hard X-ray photoemission microscopy. • Soft X-ray standing wave ambient pressure photoemission spectroscopy from liquid films. - Abstract: The evolution of both information and energy technology is intimately connected to complex condensed matter systems, the properties of which are determined by electronic and chemical interactions and processes on a broad range of length and time scales. Dedicated photoelectron spectroscopy and spectromicroscopy experiments can provide important insights into fundamental phenomena and applied functionalities. We discuss some recent methodological developments with application to relevant questions in spintronics, and towards operando studies of resistive switching and electrochemical processes.
HIGH-RESOLUTION ROTATIONAL SPECTRUM, DUNHAM COEFFICIENTS, AND POTENTIAL ENERGY FUNCTION OF NaCl
International Nuclear Information System (INIS)
Cabezas, C.; Peña, I.; Alonso, J. L.; Cernicharo, J.; Quintana-Lacaci, G.; Agundez, M.; Prieto, L. Velilla; Castro-Carrizo, A.; Zuñiga, J.; Bastida, A.; Requena, A.
2016-01-01
We report laboratory spectroscopy for the first time of the J = 1–0 and J = 2–1 lines of Na 35 Cl and Na 37 Cl in several vibrational states. The hyperfine structure has been resolved in both transitions for all vibrational levels, which permit us to predict with high accuracy the hyperfine splitting of the rotational transitions of the two isotopologues at higher frequencies. The new data have been merged with all previous works at microwave, millimeter, and infrared wavelengths and fitted to a series of mass-independent Dunham parameters and to a potential energy function. The obtained parameters have been used to compute a new dipole moment function, from which the dipole moment for infrared transitions up to Δ v = 8 has been derived. Frequency and intensity predictions are provided for all rovibrational transitions up to J = 150 and v = 8, from which the ALMA data of evolved stars can be modeled and interpreted.
High energy QCD at NLO: from light-cone wave function to JIMWLK evolution
Energy Technology Data Exchange (ETDEWEB)
Lublinsky, Michael [Department of Physics, Ben-Gurion University of the Negev,Beer-Sheva 84105 (Israel); Physics Department, University of Connecticut,2152 Hillside Road, Storrs, CT 06269-3046 (United States); Mulian, Yair [Department of Physics, Ben-Gurion University of the Negev,Beer-Sheva 84105 (Israel)
2017-05-17
Soft components of the light cone wave-function of a fast moving projectile hadron is computed in perturbation theory to the third order in QCD coupling constant. At this order, the Fock space of the soft modes consists of one-gluon, two-gluon, and a quark-antiquark states. The hard component of the wave-function acts as a non-Abelian background field for the soft modes and is represented by a valence charge distribution that accounts for non-linear density effects in the projectile. When scattered off a dense target, the diagonal element of the S-matrix reveals the Hamiltonian of high energy evolution, the JIMWLK Hamiltonian. This way we provide a new direct derivation of the JIMWLK Hamiltonian at the Next-to-Leading Order.
HIGH-RESOLUTION ROTATIONAL SPECTRUM, DUNHAM COEFFICIENTS, AND POTENTIAL ENERGY FUNCTION OF NaCl
Energy Technology Data Exchange (ETDEWEB)
Cabezas, C.; Peña, I.; Alonso, J. L. [Grupo de Espectroscopía Molecular, Edificio Quifima, Laboratorios de Espectroscopía y Bioespectroscopía, Unidad asociada CSIC, Parque científico Uva, Universidad de Valladolid, Paseo de Belén 5, E-47011, Valladolid (Spain); Cernicharo, J.; Quintana-Lacaci, G.; Agundez, M.; Prieto, L. Velilla [Group of Molecular Astrophysics, ICMM, CSIC. C/Sor Juana Inés de la Cruz 3, E-28049 Cantoblanco, Madrid (Spain); Castro-Carrizo, A. [Institut de Radioastronomie Millimétrique, 300 rue de la la Piscine, F-38406, Saint Martin d’Hères (France); Zuñiga, J.; Bastida, A.; Requena, A. [Universidad de Murcia. Faculdad de Química, Dpto. de Química-Física, Campus Espinardo E-30100, Murcia (Spain)
2016-07-10
We report laboratory spectroscopy for the first time of the J = 1–0 and J = 2–1 lines of Na{sup 35}Cl and Na{sup 37}Cl in several vibrational states. The hyperfine structure has been resolved in both transitions for all vibrational levels, which permit us to predict with high accuracy the hyperfine splitting of the rotational transitions of the two isotopologues at higher frequencies. The new data have been merged with all previous works at microwave, millimeter, and infrared wavelengths and fitted to a series of mass-independent Dunham parameters and to a potential energy function. The obtained parameters have been used to compute a new dipole moment function, from which the dipole moment for infrared transitions up to Δ v = 8 has been derived. Frequency and intensity predictions are provided for all rovibrational transitions up to J = 150 and v = 8, from which the ALMA data of evolved stars can be modeled and interpreted.
International Nuclear Information System (INIS)
Peterson, K.A.; Dunning, T.H. Jr.
1995-01-01
The hydrogen bond energy and geometry of the HF dimer have been investigated using the series of correlation consistent basis sets from aug-cc-pVDZ to aug-cc-pVQZ and several theoretical methods including Moller--Plesset perturbation and coupled cluster theories. Estimates of the complete basis set (CBS) limit have been derived for the binding energy of (HF) 2 at each level of theory by utilizing the regular convergence characteristics of the correlation consistent basis sets. CBS limit hydrogen bond energies of 3.72, 4.53, 4.55, and 4.60 kcal/mol are estimated at the SCF, MP2, MP4, and CCSD(T) levels of theory, respectively. CBS limits for the intermolecular F--F distance are estimated to be 2.82, 2.74, 2.73, and 2.73 A, respectively, for the same correlation methods. The effects of basis set superposition error (BSSE) on both the binding energies and structures have also been investigated for each basis set using the standard function counterpoise (CP) method. While BSSE has a negligible effect on the intramolecular geometries, the CP-corrected F--F distance and binding energy differ significantly from the uncorrected values for the aug-cc-pVDZ basis set; these differences decrease regularly with increasing basis set size, yielding the same limits in the CBS limit. Best estimates for the equilibrium properties of the HF dimer from CCSD(T) calculations are D e =4.60 kcal/mol, R FF =2.73 A, r 1 =0.922 A, r 2 =0.920 A, Θ 1 =7 degree, and Θ 2 =111 degree
International Nuclear Information System (INIS)
Balzer, Matthias
2008-01-01
The central goal of this thesis is the examination of strongly correlated electron systems on the basis of the two-dimensional Hubbard model. We analyze how the properties of the Mott insulator change upon doping and with interaction strength. The numerical evaluation is done using quantum cluster approximations, which allow for a thermodynamically consistent description of the ground state properties. The framework of self-energy-functional theory offers great flexibility for the construction of cluster approximations. A detailed analysis sheds light on the quality and the convergence properties of different cluster approximations within the self-energy-functional theory. We use the one-dimensional Hubbard model for these examinations and compare our results with the exact solution. In two dimensions the ground state of the particle-hole symmetric model at half-filling is an antiferromagnetic insulator, independent of the interaction strength. The inclusion of short-range spatial correlations by our cluster approach leads to a considerable improvement of the antiferromagnetic order parameter as compared to dynamical mean-field theory. In the paramagnetic phase we furthermore observe a metal-insulator transition as a function of the interaction strength, which qualitatively differs from the pure mean-field scenario. Starting from the antiferromagnetic Mott insulator a filling-controlled metal-insulator transition in a paramagnetic metallic phase can be observed. Depending on the cluster approximation used an antiferromagnetic metallic phase may occur at first. In addition to long-range antiferromagnetic order, we also considered superconductivity in our calculations. The superconducting order parameter as a function of doping is in good agreement with other numerical methods, as well as with experimental results. (orig.)
Trickey, Samuel; Karasiev, Valentin
We introduce the concept of tunable orbital-free non-interacting free-energy density functionals and present a generalized gradient approximation (GGA) with a subset of parameters defined from constraints and a few free parameters. Those free parameters are tuned to reproduce reference Kohn-Sham (KS) static-lattice pressures for Al at T=8 kK for bulk densities between 0.6 and 2 g/cm3. The tuned functional then is used in OF molecular dynamics (MD) simulations for Al with densities between 0.1 and 2 g/cm3 and T between 6 and 50 kK to calculate the equation of state and generate configurations for electrical conductivity calculations. The tunable functional produces accurate results. Computationally it is very effective especially at elevated temperature. Kohn-Shiam calculations for such low densities are affordable only up to T=10 kK, while other OF approximations, including two-point functionals, fail badly in that regime. Work supported by US DoE Grant DE-SC0002139.
International Nuclear Information System (INIS)
Meister, F.; Ott, F.
2002-01-01
This chapter gives an overview of the current energy economy in Austria. The Austrian political aims of sustainable development and climate protection imply a reorientation of the Austrian energy policy as a whole. Energy consumption trends (1993-1998), final energy consumption by energy carrier (indexed data 1993-1999), comparative analysis of useful energy demand (1993 and 1999) and final energy consumption of renewable energy sources by sector (1996-1999) in Austria are given. The necessary measures to be taken in order to reduce the energy demand and increased the use of renewable energy are briefly mentioned. Figs. 5. (nevyjel)
Harris, Robert C; Deng, Nanjie; Levy, Ronald M; Ishizuka, Ryosuke; Matubayasi, Nobuyuki
2017-06-05
Many biomolecules undergo conformational changes associated with allostery or ligand binding. Observing these changes in computer simulations is difficult if their timescales are long. These calculations can be accelerated by observing the transition on an auxiliary free energy surface with a simpler Hamiltonian and connecting this free energy surface to the target free energy surface with free energy calculations. Here, we show that the free energy legs of the cycle can be replaced with energy representation (ER) density functional approximations. We compute: (1) The conformational free energy changes for alanine dipeptide transitioning from the right-handed free energy basin to the left-handed basin and (2) the free energy difference between the open and closed conformations of β-cyclodextrin, a "host" molecule that serves as a model for molecular recognition in host-guest binding. β-cyclodextrin contains 147 atoms compared to 22 atoms for alanine dipeptide, making β-cyclodextrin a large molecule for which to compute solvation free energies by free energy perturbation or integration methods and the largest system for which the ER method has been compared to exact free energy methods. The ER method replaced the 28 simulations to compute each coupling free energy with two endpoint simulations, reducing the computational time for the alanine dipeptide calculation by about 70% and for the β-cyclodextrin by > 95%. The method works even when the distribution of conformations on the auxiliary free energy surface differs substantially from that on the target free energy surface, although some degree of overlap between the two surfaces is required. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.
Description of odd-mass nuclei by multi-reference energy density functional methods
International Nuclear Information System (INIS)
Bally, B.
2014-01-01
In this work, we are interested in the treatment of odd-mass atomic nuclei in energy density functional (EDF) models. More precisely, the goal of this thesis is to develop and to apply to odd-mass nuclei, the theoretical extensions of the EDF method that are: first, the projection technique, and secondly the configuration mixing by the generator coordinate method (GCM). These two extensions are part of the so-called multi-reference energy density functional (MR-EDF) formalism and allow one to take into account, within an EDF context, the 'beyond-mean-field' correlations between the nucleons forming the nucleus. Until now, the MR-EDF formalism has been applied, in its fully-fledged version, only to the calculation of even-even nuclei. In this thesis, we want to demonstrate the applicability of such a model also for the description of odd-mass nuclei. In the first part of this thesis, we describe the theoretical formalism of the EDF models, giving particular attention to the treatment of symmetries within our approach. In the second part of the manuscript, we apply our model to the nucleus 25 Mg and investigate different aspects of the method (e.g. numerical accuracy, convergence of the configuration mixing, comparison to known experimental data). The results obtained in this work are encouraging and demonstrate the potential of our approach for theoretical nuclear structure calculations. (author)
Convexity of Energy-Like Functions: Theoretical Results and Applications to Power System Operations
Energy Technology Data Exchange (ETDEWEB)
Dvijotham, Krishnamurthy [California Inst. of Technology (CalTech), Pasadena, CA (United States); Low, Steven [California Inst. of Technology (CalTech), Pasadena, CA (United States); Chertkov, Michael [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
2015-01-12
Power systems are undergoing unprecedented transformations with increased adoption of renewables and distributed generation, as well as the adoption of demand response programs. All of these changes, while making the grid more responsive and potentially more efficient, pose significant challenges for power systems operators. Conventional operational paradigms are no longer sufficient as the power system may no longer have big dispatchable generators with sufficient positive and negative reserves. This increases the need for tools and algorithms that can efficiently predict safe regions of operation of the power system. In this paper, we study energy functions as a tool to design algorithms for various operational problems in power systems. These have a long history in power systems and have been primarily applied to transient stability problems. In this paper, we take a new look at power systems, focusing on an aspect that has previously received little attention: Convexity. We characterize the domain of voltage magnitudes and phases within which the energy function is convex in these variables. We show that this corresponds naturally with standard operational constraints imposed in power systems. We show that power of equations can be solved using this approach, as long as the solution lies within the convexity domain. We outline various desirable properties of solutions in the convexity domain and present simple numerical illustrations supporting our results.
Disentangling interacting dark energy cosmologies with the three-point correlation function
Moresco, Michele; Marulli, Federico; Baldi, Marco; Moscardini, Lauro; Cimatti, Andrea
2014-10-01
We investigate the possibility of constraining coupled dark energy (cDE) cosmologies using the three-point correlation function (3PCF). Making use of the CODECS N-body simulations, we study the statistical properties of cold dark matter (CDM) haloes for a variety of models, including a fiducial ΛCDM scenario and five models in which dark energy (DE) and CDM mutually interact. We measure both the halo 3PCF, ζ(θ), and the reduced 3PCF, Q(θ), at different scales (2 values of the halo 3PCF for perpendicular (elongated) configurations. The effect is also scale-dependent, with differences between ΛCDM and cDE models that increase at large scales. We made use of these measurements to estimate the halo bias, that results in fair agreement with the one computed from the two-point correlation function (2PCF). The main advantage of using both the 2PCF and 3PCF is to break the bias-σ8 degeneracy. Moreover, we find that our bias estimates are approximately independent of the assumed strength of DE coupling. This study demonstrates the power of a higher order clustering analysis in discriminating between alternative cosmological scenarios, for both present and forthcoming galaxy surveys, such as e.g. Baryon Oscillation Spectroscopic Survey and Euclid.
Pair distribution functions of carbonaceous solids, determined using energy filtered diffraction
International Nuclear Information System (INIS)
Petersen, T.C.; McCulloch, D.G.
2002-01-01
Full text: The structures of various carbonaceous solids were investigated using energy filtered diffraction patterns collected in two dimensions using a Gatan Imaging Filter (GIF). In order to reduce multiple scattering and eliminate inelastic scattering effects, the diffraction patterns were filtered using an energy -selecting slit around the zero-loss peak. Software has been developed for the extraction of radially averaged pair distributions functions from the diffraction data. This entails finding the position of the un-scattered beam, radially averaging the two dimensional intensity distributions, calibrating the resulting one dimensional intensity profiles and finally normalising the data to obtain structure factors. Techniques for improving and assessing data quality, pertaining to the methodology used here, have also been explored. Structure factors and radial distribution functions generated using this analysis will be discussed and, for the commercial V25 glassy carbon samples, compared to previous, work of one of the authors'. In order to answer questions regarding multiple scattering effects and structural homogeneity of the samples, neutron scattering was performed on the Medium Resolution Powder Diffractometer (MRPD), at the Australian Nuclear Science and Technology's (ANSTO) facility. A critical comparison of the neutron scattering and electron diffraction generated structure factors will be presented. Copyright (2002) Australian Society for Electron Microscopy Inc
International Nuclear Information System (INIS)
Neumann, Martin; Zoppi, Marco
2002-01-01
We have performed extensive path integral Monte Carlo simulations of liquid and solid neon, in order to derive the kinetic energy as well as the single-particle and pair distribution functions of neon atoms in the condensed phases. From the single-particle distribution function n(r) one can derive the momentum distribution and thus obtain an independent estimate of the kinetic energy. The simulations have been carried out using mostly the semiempirical HFD-C2 pair potential by Aziz et al. [R. A. Aziz, W. J. Meath, and A. R. Allnatt, Chem. Phys. 79, 295 (1983)], but, in a few cases, we have also used the Lennard-Jones potential. The differences between the potentials, as measured by the properties investigated, are not very large, especially when compared with the actual precision of the experimental data. The simulation results have been compared with all the experimental information that is available from neutron scattering. The overall agreement with the experiments is very good
Building a Universal Nuclear Energy Density Functional (UNEDF): SciDAC-2 Project
Energy Technology Data Exchange (ETDEWEB)
Carlson, Joe; Furnstahl, Dick; Lusk, Rusty; Nazarewicz, Witek; Ng, Esmond; Thompson, Ian; Vary, James
2012-06-30
An understanding of the properties of atomic nuclei is crucial for a complete nuclear theory, for element formation, for properties of stars, and for present and future energy and defense applications. During the period of Dec. 1, 2006 - Jun. 30, 2012, the UNEDF collaboration carried out a comprehensive study of all nuclei based on the most accurate knowledge of the strong nuclear interaction, the most reliable theoretical approaches, the most advanced algorithms, and extensive computational resources, with a view towards scaling to the petaflop platforms and beyond. The long-term vision initiated with UNEDF is to arrive at a comprehensive, quantitative, and unified description of nuclei and their reactions, grounded in the fundamental interactions between the constituent nucleons. We seek to replace current phenomenological models of nuclear structure and reactions with a well-founded microscopic theory that delivers maximum predictive power with well-quantified uncertainties. Specifically, the mission of this project has been three-fold: first, to find an optimal energy density functional (EDF) using all our knowledge of the nucleonic Hamiltonian and basic nuclear properties; second, to apply the EDF theory and its extensions to validate the functional using all the available relevant nuclear structure and reaction data; and third, to apply the validated theory to properties of interest that cannot be measured, in particular the properties needed for reaction theory.
Modeling of Materials for Energy Storage: A Challenge for Density Functional Theory
Kaltak, Merzuk; Fernandez-Serra, Marivi; Hybertsen, Mark S.
Hollandite α-MnO2 is a promising material for rechargeable batteries and is studied extensively in the community because of its interesting tunnel structure and the corresponding large capacity for lithium as well as sodium ions. However, the presence of partially reduced Mn ions due to doping with Ag or during lithiation makes hollandite a challenging system for density functional theory and the conventionally employed PBE+U method. A naive attempt to model the ternary system LixAgyMnO2 with density functionals, similar to those employed for the case y = 0 , fails and predicts a strong monoclinic distortion of the experimentally observed tetragonal unit cell for Ag2Mn8O16. Structure and binding energies are compared with experimental data and show the importance of van der Waals interactions as well as the necessity for an accurate description of the cooperative Jan-Teller effects for silver hollandite AgyMnO2. Based on these observations a ternary phase diagram is calculated allowing to predict the physical and chemical properties of LixAgyMnO2, such as stable stoichiometries, open circuit voltages, the formation of Ag metal and the structural change during lithiation. Department of Energy (DOE) under award #DE-SC0012673.
Bufalo, Gennaro; Ambrosone, Luigi
2016-01-14
A method for studying the kinetics of thermal degradation of complex compounds is suggested. Although the method is applicable to any matrix whose grain size can be measured, herein we focus our investigation on thermogravimetric analysis, under a nitrogen atmosphere, of ground soft wheat and ground maize. The thermogravimetric curves reveal that there are two well-distinct jumps of mass loss. They correspond to volatilization, which is in the temperature range 298-433 K, and decomposition regions go from 450 to 1073 K. Thermal degradation is schematized as a reaction in the solid state whose kinetics is analyzed separately in each of the two regions. By means of a sieving analysis different size fractions of the material are separated and studied. A quasi-Newton fitting algorithm is used to obtain the grain size distribution as best fit to experimental data. The individual fractions are thermogravimetrically analyzed for deriving the functional relationship between activation energy of the degradation reactions and the particle size. Such functional relationship turns out to be crucial to evaluate the moments of the activation energy distribution, which is unknown in terms of the distribution calculated by sieve analysis. From the knowledge of moments one can reconstruct the reaction conversion. The method is applied first to the volatilization region, then to the decomposition region. The comparison with the experimental data reveals that the method reproduces the experimental conversion with an accuracy of 5-10% in the volatilization region and of 3-5% in the decomposition region.
International Nuclear Information System (INIS)
Meister, F.
2001-01-01
This chapter of the environmental control report deals with the environmental impact of energy production, energy conversion, atomic energy and renewable energy. The development of the energy consumption in Austria for the years 1993 to 1999 is given for the different energy types. The development of the use of renewable energy sources in Austria is given, different domestic heat-systems are compared, life cycles and environmental balance are outlined. (a.n.)
Active surface model improvement by energy function optimization for 3D segmentation.
Azimifar, Zohreh; Mohaddesi, Mahsa
2015-04-01
This paper proposes an optimized and efficient active surface model by improving the energy functions, searching method, neighborhood definition and resampling criterion. Extracting an accurate surface of the desired object from a number of 3D images using active surface and deformable models plays an important role in computer vision especially medical image processing. Different powerful segmentation algorithms have been suggested to address the limitations associated with the model initialization, poor convergence to surface concavities and slow convergence rate. This paper proposes a method to improve one of the strongest and recent segmentation algorithms, namely the Decoupled Active Surface (DAS) method. We consider a gradient of wavelet edge extracted image and local phase coherence as external energy to extract more information from images and we use curvature integral as internal energy to focus on high curvature region extraction. Similarly, we use resampling of points and a line search for point selection to improve the accuracy of the algorithm. We further employ an estimation of the desired object as an initialization for the active surface model. A number of tests and experiments have been done and the results show the improvements with regards to the extracted surface accuracy and computational time of the presented algorithm compared with the best and recent active surface models. Copyright © 2015 Elsevier Ltd. All rights reserved.
Han, Sungwon; Auger, Christopher; Thomas, Sean C; Beites, Crestina L; Appanna, Vasu D
2014-02-01
The significance of metabolic networks in guiding the fate of the stem cell differentiation is only beginning to emerge. Oxidative metabolism has been suggested to play a major role during this process. Therefore, it is critical to understand the underlying mechanisms of metabolic alterations occurring in stem cells to manipulate the ultimate outcome of these pluripotent cells. Here, using P19 murine embryonal carcinoma cells as a model system, the role of mitochondrial biogenesis and the modulation of metabolic networks during dimethyl sulfoxide (DMSO)-induced differentiation are revealed. Blue native polyacrylamide gel electrophoresis (BN-PAGE) technology aided in profiling key enzymes, such as hexokinase (HK) [EC 2.7.1.1], glucose-6-phosphate isomerase (GPI) [EC 5.3.1.9], pyruvate kinase (PK) [EC 2.7.1.40], Complex I [EC 1.6.5.3], and Complex IV [EC 1.9.3.1], that are involved in the energy budget of the differentiated cells. Mitochondrial adenosine triphosphate (ATP) production was shown to be increased in DMSO-treated cells upon exposure to the tricarboxylic acid (TCA) cycle substrates, such as succinate and malate. The increased mitochondrial activity and biogenesis were further confirmed by immunofluorescence microscopy. Collectively, the results indicate that oxidative energy metabolism and mitochondrial biogenesis were sharply upregulated in DMSO-differentiated P19 cells. This functional metabolic and proteomic study provides further evidence that modulation of mitochondrial energy metabolism is a pivotal component of the cellular differentiation process and may dictate the final destiny of stem cells.
High-sensitivity measurements of the excitation function for Bhabha scattering at MeV energies
International Nuclear Information System (INIS)
Tsertos, H.; Kozhuharov, C.; Armbruster, P.; Kienle, P.; Krusche, B.; Schreckenbach, K.
1989-02-01
Using a monochromatic e + beam scattered on a Be foil and a high-resolution detector device, the excitation function for elastic e + e - scattering was measured with a statistical accuracy of 0.25% in 1.4 keV steps in the c.m.-energy range between 770 keV and 840 keV (1.79 - 1.86 MeV/c 2 ) at c.m. scattering angles between 80 0 and 100 0 (FWHM). Within the experimental sensitivity of 0.5 b.eV/sr (c.m.) for the energy-integrated differential cross section no resonances were observed (97% CL). From this limit we infer that a hypothetical spinless resonant state should have a width of less than 1.9 meV corresponding to a lifetime limit of 3.5x10 -13 s. This limit establishes the most stringent bound for new particles in this mass range derived from Bhabha scattering and is independent of assumptions about the internal structure of the hypothetical particles. Less sensitivite limits were, in addition, derived around 520 keV c.m. energy (≅ 1.54 MeV/c 2 ) from an investigation with a thorium and a mylar foil as scatterers. (orig.)
Bower, Ward
2011-09-01
An overview of the activities and progress made during the US DOE Solar Energy Grid Integration Systems (SEGIS) solicitation, while maintaining reliability and economics is provided. The SEGIS R&D opened pathways for interconnecting PV systems to intelligent utility grids and micro-grids of the future. In addition to new capabilities are "value added" features. The new hardware designs resulted in smaller, less material-intensive products that are being viewed by utilities as enabling dispatchable generation and not just unpredictable negative loads. The technical solutions enable "advanced integrated system" concepts and "smart grid" processes to move forward in a faster and focused manner. The advanced integrated inverters/controllers can now incorporate energy management functionality, intelligent electrical grid support features and a multiplicity of communication technologies. Portals for energy flow and two-way communications have been implemented. SEGIS hardware was developed for the utility grid of today, which was designed for one-way power flow, for intermediate grid scenarios, AND for the grid of tomorrow, which will seamlessly accommodate managed two-way power flows as required by large-scale deployment of solar and other distributed generation. The SEGIS hardware and control developed for today meets existing standards and codes AND provides for future connections to a "smart grid" mode that enables utility control and optimized performance.
Ellis-Gibbings, L.; Krupa, K.; Colmenares, R.; Blanco, F.; Muńoz, A.; Mendes, M.; Ferreira da Silva, F.; Limá Vieira, P.; Jones, D. B.; Brunger, M. J.; García, G.
2016-09-01
Recent theoretical and experimental studies have provided a complete set of differential and integral electron scattering cross section data from furfural over a broad energy range. The energy loss distribution functions have been determined in this study by averaging electron energy loss spectra for different incident energies and scattering angles. All these data have been used as input parameters for an event by event Monte Carlo simulation procedure to obtain the electron energy deposition patterns and electron ranges in liquid furfural. The dependence of these results on the input cross sections is then analysed to determine the uncertainty of the simulated values.
International Nuclear Information System (INIS)
Chahine, C.; College de France, 75 - Paris. Lab. de Physique Corpusculaire)
1978-02-01
The concept of a real photon spectral weight function for any cross-section involving charged particles is introduced as a simple approximation taking into account the soft part of photon emission to all orders in perturbation theory. The spectral weight function replaces the energy-momentum conservation delta function in the elastic cross-section. The spectral weight function is computed in closed form in space-time and in the peaking approximation in momentum space. The spectral weight function description is applied to the imaginary part of vacuum polarization ImPI and to electron-proton scattering. A spectral representation for ImPI is derived and its content compared with the known fourth order result, showing in particular the identity of the soft and peaking approximations in lowest order. The virtual photon radiative corrections are discussed in part, with emphasis on the threshold behavior of the vertex functions. A relativistic generalization of the electric non-relativistic vertex function is given, whose asymptotic behavior is approppriate to use in conjuction with the spectral weight function
Alcohol mixed with energy drinks: Associations with risky drinking and functioning in high school.
Tucker, Joan S; Troxel, Wendy M; Ewing, Brett A; D'Amico, Elizabeth J
2016-10-01
Mixing alcohol with energy drinks is associated with heavier drinking and related problems among college students. However, little is known about how high school drinkers who mix alcohol with energy drinks (AmED) compare to those who do not (AwoED). This study compares high school AmED and AwoED users on their alcohol use during middle and high school, as well as key domains of functioning in high school. Two surveys were conducted three years apart in adolescents initially recruited from 16 middle schools in Southern California. The analytic sample consists of 696 past month drinkers. Multivariable models compared AmED and AwoED users on alcohol use, mental health, social functioning, academic orientation, delinquency and other substance use at age 17, and on their alcohol use and related cognitions at age 14. AmED was reported by 13% of past month drinkers. AmED and AwoED users did not differ on alcohol use or cognitions in middle school, but AmED users drank more often, more heavily, and reported more negative consequences in high school. AmED users were also more likely to report poor grades, delinquent behavior, substance use-related unsafe driving, public intoxication, and drug use than AwoED users in high school. Group differences were not found on mental health, social functioning, or academic aspirations. AmED use is common among high school drinkers. The higher risk behavioral profile of these young AmED users, which includes drug use and substance use-related unsafe driving, is a significant cause for concern and warrants further attention. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.
Riediger, Thomas
2012-11-01
The hypothalamic arcuate nucleus (ARC) and the area postrema (AP) represent targets for hormonal and metabolic signals involved in energy homoeostasis, e.g. glucose, amylin, insulin, leptin, peptide YY (PYY), glucagon-like peptide 1 (GLP-1) and ghrelin. Orexigenic neuropeptide Y expressing ARC neurons are activated by food deprivation and inhibited by feeding in a nutrient-dependent manner. PYY and leptin also reverse or prevent fasting-induced activation of the ARC. Interestingly, hypothalamic responses to fasting are blunted in different models of obesity (e.g. diet-induced obesity (DIO) or late-onset obesity). The AP also responds to feeding-related signals. The pancreatic hormone amylin acts via the AP to control energy intake. Amylin-sensitive AP neurons are also glucose-responsive. Furthermore, diet-derived protein attenuates amylin responsiveness suggesting a modulation of AP sensitivity by macronutrient supply. This review gives an overview of the receptive function of the ARC and the AP to hormonal and nutritional stimuli involved in the control of energy balance and the possible implications in the context of obesity. Collectively, there is consistency between the neurophysiological actions of these stimuli and their effects on energy homoeostasis under experimental conditions. However, surprisingly little progress has been made in the development of effective pharmacological approaches against obesity. A promising way to improve effectiveness involves combination treatments (e.g. amylin/leptin agonists). Hormonal alterations (e.g. GLP-1 and PYY) are also considered to mediate body weight loss observed in obese patients receiving bariatric surgery. The effects of hormonal and nutritional signals and their interactions might hold the potential to develop poly-mechanistic therapeutic strategies against obesity.
Soraya, N. W.; El Hadi, R. M.; Chumaidiyah, E.; Tripiawan, W.
2017-12-01
Conventional drying process is constrained by weather (cloudy / rainy), and requires wide drying area, and provides low-quality product. Multi-function dual energy oven is the appropriate technology to solve these problems. The oven uses solar thermal or gas heat for drying various type of products, including tapioca crackers. Investment analysis in technical, operational, and financial aspects show that the multi-function dual energy oven is feasible to be implemented for small medium enterprise (SME) processing tapioca crackers.
Navarro Pérez, R.; Schunck, N.; Dyhdalo, A.; Furnstahl, R. J.; Bogner, S. K.
2018-05-01
Background: Energy density functional methods provide a generic framework to compute properties of atomic nuclei starting from models of nuclear potentials and the rules of quantum mechanics. Until now, the overwhelming majority of functionals have been constructed either from empirical nuclear potentials such as the Skyrme or Gogny forces, or from systematic gradient-like expansions in the spirit of the density functional theory for atoms. Purpose: We seek to obtain a usable form of the nuclear energy density functional that is rooted in the modern theory of nuclear forces. We thus consider a functional obtained from the density matrix expansion of local nuclear potentials from chiral effective field theory. We propose a parametrization of this functional carefully calibrated and validated on selected ground-state properties that is suitable for large-scale calculations of nuclear properties. Methods: Our energy functional comprises two main components. The first component is a non-local functional of the density and corresponds to the direct part (Hartree term) of the expectation value of local chiral potentials on a Slater determinant. Contributions to the mean field and the energy of this term are computed by expanding the spatial, finite-range components of the chiral potential onto Gaussian functions. The second component is a local functional of the density and is obtained by applying the density matrix expansion to the exchange part (Fock term) of the expectation value of the local chiral potential. We apply the UNEDF2 optimization protocol to determine the coupling constants of this energy functional. Results: We obtain a set of microscopically constrained functionals for local chiral potentials from leading order up to next-to-next-to-leading order with and without three-body forces and contributions from Δ excitations. These functionals are validated on the calculation of nuclear and neutron matter, nuclear mass tables, single-particle shell structure
Smith, Keith; Ricaud, Benjamin; Shahid, Nauman; Rhodes, Stephen; Starr, John M.; Ibáñez, Augustin; Parra, Mario A.; Escudero, Javier; Vandergheynst, Pierre
2017-02-01
Visual short-term memory binding tasks are a promising early marker for Alzheimer’s disease (AD). To uncover functional deficits of AD in these tasks it is meaningful to first study unimpaired brain function. Electroencephalogram recordings were obtained from encoding and maintenance periods of tasks performed by healthy young volunteers. We probe the task’s transient physiological underpinnings by contrasting shape only (Shape) and shape-colour binding (Bind) conditions, displayed in the left and right sides of the screen, separately. Particularly, we introduce and implement a novel technique named Modular Dirichlet Energy (MDE) which allows robust and flexible analysis of the functional network with unprecedented temporal precision. We find that connectivity in the Bind condition is less integrated with the global network than in the Shape condition in occipital and frontal modules during the encoding period of the right screen condition. Using MDE we are able to discern driving effects in the occipital module between 100-140 ms, coinciding with the P100 visually evoked potential, followed by a driving effect in the frontal module between 140-180 ms, suggesting that the differences found constitute an information processing difference between these modules. This provides temporally precise information over a heterogeneous population in promising tasks for the detection of AD.
Sun, Jianwei; Remsing, Richard C; Zhang, Yubo; Sun, Zhaoru; Ruzsinszky, Adrienn; Peng, Haowei; Yang, Zenghui; Paul, Arpita; Waghmare, Umesh; Wu, Xifan; Klein, Michael L; Perdew, John P
2016-09-01
One atom or molecule binds to another through various types of bond, the strengths of which range from several meV to several eV. Although some computational methods can provide accurate descriptions of all bond types, those methods are not efficient enough for many studies (for example, large systems, ab initio molecular dynamics and high-throughput searches for functional materials). Here, we show that the recently developed non-empirical strongly constrained and appropriately normed (SCAN) meta-generalized gradient approximation (meta-GGA) within the density functional theory framework predicts accurate geometries and energies of diversely bonded molecules and materials (including covalent, metallic, ionic, hydrogen and van der Waals bonds). This represents a significant improvement at comparable efficiency over its predecessors, the GGAs that currently dominate materials computation. Often, SCAN matches or improves on the accuracy of a computationally expensive hybrid functional, at almost-GGA cost. SCAN is therefore expected to have a broad impact on chemistry and materials science.
A Robust, Water-Based, Functional Binder Framework for High-Energy Lithium-Sulfur Batteries.
Lacey, Matthew J; Österlund, Viking; Bergfelt, Andreas; Jeschull, Fabian; Bowden, Tim; Brandell, Daniel
2017-07-10
We report here a water-based functional binder framework for the lithium-sulfur battery systems, based on the general combination of a polyether and an amide-containing polymer. These binders are applied to positive electrodes optimised towards high-energy electrochemical performance based only on commercially available materials. Electrodes with up to 4 mAh cm -2 capacity and 97-98 % coulombic efficiency are achievable in electrodes with a 65 % total sulfur content and a poly(ethylene oxide):poly(vinylpyrrolidone) (PEO:PVP) binder system. Exchange of either binder component for a different polymer with similar functionality preserves the high capacity and coulombic efficiency. The improvement in coulombic efficiency from the inclusion of the coordinating amide group was also observed in electrodes where pyrrolidone moieties were covalently grafted to the carbon black, indicating the role of this functionality in facilitating polysulfide adsorption to the electrode surface. The mechanical properties of the electrodes appear not to significantly influence sulfur utilisation or coulombic efficiency in the short term but rather determine retention of these properties over extended cycling. These results demonstrate the robustness of this very straightforward approach, as well as the considerable scope for designing binder materials with targeted properties. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.
Liang, Hui; He, Shiming; Yang, Jingyi; Jia, Xinying; Wang, Pan; Chen, Xi; Zhang, Zhong; Zou, Xiajuan; McNutt, Michael A; Shen, Wen Hong; Yin, Yuxin
2014-05-06
PTEN is one of the most frequently mutated genes in human cancer. It is known that PTEN has a wide range of biological functions beyond tumor suppression. Here, we report that PTENα, an N-terminally extended form of PTEN, functions in mitochondrial metabolism. Translation of PTENα is initiated from a CUG codon upstream of and in-frame with the coding region of canonical PTEN. Eukaryotic translation initiation factor 2A (eIF2A) controls PTENα translation, which requires a CUG-centered palindromic motif. We show that PTENα induces cytochrome c oxidase activity and ATP production in mitochondria. TALEN-mediated somatic deletion of PTENα impairs mitochondrial respiratory chain function. PTENα interacts with canonical PTEN to increase PINK1 protein levels and promote energy production. Our studies demonstrate the importance of eIF2A-mediated alternative translation for generation of protein diversity in eukaryotic systems and provide insights into the mechanism by which the PTEN family is involved in multiple cellular processes. Copyright © 2014 Elsevier Inc. All rights reserved.
Lee, Kyungtae; Gu, Geun Ho; Mullen, Charles A; Boateng, Akwasi A; Vlachos, Dionisios G
2015-01-01
Density functional theory is used to study the adsorption of guaiacol and its initial hydrodeoxygenation (HDO) reactions on Pt(111). Previous Brønsted-Evans-Polanyi (BEP) correlations for small open-chain molecules are inadequate in estimating the reaction barriers of phenolic compounds except for the side group (methoxy) carbon-dehydrogenation. New BEP relations are established using a select group of phenolic compounds. These relations are applied to construct a potential-energy surface of guaiacol-HDO to catechol. Analysis shows that catechol is mainly produced via dehydrogenation of the methoxy functional group followed by the CHx (x<3) removal of the functional group and hydrogenation of the ring carbon, in contrast to a hypothesis of a direct demethylation path. Dehydroxylation and demethoxylation are slow, implying that phenol is likely produced from catechol but not through its direct dehydroxylation followed by aromatic carbon-ring hydrogenation. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Ion Binding Energies Determining Functional Transport of ClC Proteins
Yu, Tao; Guo, Xu; Zou, Xian-Wu; Sang, Jian-Ping
2014-06-01
The ClC-type proteins, a large family of chloride transport proteins ubiquitously expressed in biological organisms, have been extensively studied for decades. Biological function of ClC proteins can be reflected by analyzing the binding situation of Cl- ions. We investigate ion binding properties of ClC-ec1 protein with the atomic molecular dynamics simulation approach. The calculated electrostatic binding energy results indicate that Cl- at the central binding site Scen has more binding stability than the internal binding site Sint. Quantitative comparison between the latest experimental heat release data isothermal titration calorimetry (ITC) and our calculated results demonstrates that chloride ions prefer to bind at Scen than Sint in the wild-type ClC-ec1 structure and prefer to bind at Sext and Scen than Sint in mutant E148A/E148Q structures. Even though the chloride ions make less contribution to heat release when binding to Sint and are relatively unstable in the Cl- pathway, they are still part contributors for the Cl- functional transport. This work provides a guide rule to estimate the importance of Cl- at the binding sites and how chloride ions have influences on the function of ClC proteins.
2010-04-01
... 23 Highways 1 2010-04-01 2010-04-01 false National Reference Energy Mean Emission Levels as a Function of Speed A Appendix A to Part 772 Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF... NOISE Pt. 772, App. A Appendix A to Part 772—National Reference Energy Mean Emission Levels as a...
DEFF Research Database (Denmark)
List, Nanna Holmgaard; Olsen, Jógvan Magnus Haugaard; Rocha-Rinza, Tomás
2012-01-01
this task. We present an evaluation of the performance of commonly used XC-functionals for the prediction of excitation energies of GFP-like chromophores. In particular, we have considered the TD-DFT vertical excitation energies of chromophores displaying different charge states. We compare the quality...
Adamczyk, L.; Adkins, J. K.; Agakishiev, G.; Aggarwal, M. M.; Ahammed, Z.; Alekseev, I.; Alford, J.; Aparin, A.; Arkhipkin, D.; Aschenauer, E. C.; Averichev, G. S.; Banerjee, A.; Bellwied, R.; Bhasin, A.; Bhati, A. K.; Bhattarai, P.; Bielcik, J.; Bielcikova, J.; Bland, L. C.; Bordyuzhin, I. G.; Bouchet, J.; Brandin, A. V.; Bunzarov, I.; Burton, T. P.; Butterworth, J.; Caines, H.; Calderón de la Barca Sánchez, M.; Campbell, J. M.; Cebra, D.; Cervantes, M. C.; Chakaberia, I.; Chaloupka, P.; Chang, Z.; Chattopadhyay, S.; Chen, J. H.; Chen, H. F.; Cheng, J.; Cherney, M.; Christie, W.; Codrington, M. J. M.; Contin, G.; Crawford, H. J.; Cui, X.; Das, S.; De Silva, L. C.; Debbe, R. R.; Dedovich, T. G.; Deng, J.; Derevschikov, A. A.; Derradi de Souza, R.; di Ruzza, B.; Didenko, L.; Dilks, C.; Dong, X.; Drachenberg, J. L.; Draper, J. E.; Du, C. M.; Dunkelberger, L. E.; Dunlop, J. C.; Efimov, L. G.; Engelage, J.; Eppley, G.; Esha, R.; Evdokimov, O.; Eyser, O.; Fatemi, R.; Fazio, S.; Federic, P.; Fedorisin, J.; Feng, Filip, P.; Fisyak, Y.; Flores, C. E.; Gagliardi, C. A.; Garand, D.; Geurts, F.; Gibson, A.; Girard, M.; Greiner, L.; Grosnick, D.; Gunarathne, D. S.; Guo, Y.; Gupta, A.; Gupta, S.; Guryn, W.; Hamad, A.; Hamed, A.; Han, L.-X.; Haque, R.; Harris, J. W.; Heppelmann, S.; Hirsch, A.; Hoffmann, G. W.; Hofman, D. J.; Horvat, S.; Huang, B.; Huang, X.; Huang, H. Z.; Huck, P.; Humanic, T. J.; Igo, G.; Jacobs, W. W.; Jang, H.; Judd, E. G.; Kabana, S.; Kalinkin, D.; Kang, K.; Kauder, K.; Ke, H. W.; Keane, D.; Kechechyan, A.; Khan, Z. H.; Kikola, D. P.; Kisel, I.; Kisiel, A.; Klein, S. R.; Koetke, D. D.; Kollegger, T.; Kosarzewski, L. K.; Kotchenda, L.; Kraishan, A. F.; Kravtsov, P.; Krueger, K.; Kulakov, I.; Kumar, L.; Kycia, R. A.; Lamont, M. A. C.; Landgraf, J. M.; Landry, K. D.; Lauret, J.; Lebedev, A.; Lednicky, R.; Lee, J. H.; Li, Z. M.; Li, X.; Li, W.; Li, Y.; Li, X.; Li, C.; Lisa, M. A.; Liu, F.; Ljubicic, T.; Llope, W. J.; Lomnitz, M.; Longacre, R. S.; Luo, X.; Ma, G. L.; Ma, R. M.; Ma, Y. G.; Magdy, N.; Mahapatra, D. P.; Majka, R.; Manion, A.; Margetis, S.; Markert, C.; Masui, H.; Matis, H. S.; McDonald, D.; Minaev, N. G.; Mioduszewski, S.; Mohanty, B.; Mondal, M. M.; Morozov, D. A.; Mustafa, M. K.; Nandi, B. K.; Nasim, Md.; Nayak, T. K.; Nigmatkulov, G.; Nogach, L. V.; Noh, S. Y.; Novak, J.; Nurushev, S. B.; Odyniec, G.; Ogawa, A.; Oh, K.; Okorokov, V.; Olvitt, D. L.; Page, B. S.; Pan, Y. X.; Pandit, Y.; Panebratsev, Y.; Pawlak, T.; Pawlik, B.; Pei, H.; Perkins, C.; Pile, P.; Planinic, M.; Pluta, J.; Poljak, N.; Poniatowska, K.; Porter, J.; Poskanzer, A. M.; Pruthi, N. K.; Przybycien, M.; Putschke, J.; Qiu, H.; Quintero, A.; Ramachandran, S.; Raniwala, R.; Raniwala, S.; Ray, R. L.; Ritter, H. G.; Roberts, J. B.; Rogachevskiy, O. V.; Romero, J. L.; Roy, A.; Ruan, L.; Rusnak, J.; Rusnakova, O.; Sahoo, N. R.; Sahu, P. K.; Sakrejda, I.; Salur, S.; Sandacz, A.; Sandweiss, J.; Sarkar, A.; Schambach, J.; Scharenberg, R. P.; Schmah, A. M.; Schmidke, W. B.; Schmitz, N.; Seger, J.; Seyboth, P.; Shah, N.; Shahaliev, E.; Shanmuganathan, P. V.; Shao, M.; Sharma, B.; Shen, W. Q.; Shi, S. S.; Shou, Q. Y.; Sichtermann, E. P.; Simko, M.; Skoby, M. J.; Smirnov, N.; Smirnov, D.; Solanki, D.; Song, L.; Sorensen, P.; Spinka, H. M.; Srivastava, B.; Stanislaus, T. D. S.; Stock, R.; Strikhanov, M.; Stringfellow, B.; Sumbera, M.; Summa, B. J.; Sun, X. M.; Sun, Z.; Sun, Y.; Sun, X.; Surrow, B.; Svirida, D. N.; Szelezniak, M. A.; Takahashi, J.; Tang, Z.; Tang, A. H.; Tarnowsky, T.; Tawfik, A. N.; Thomas, J. H.; Timmins, A. R.; Tlusty, D.; Tokarev, M.; Trentalange, S.; Tribble, R. E.; Tribedy, P.; Tripathy, S. K.; Trzeciak, B. A.; Tsai, O. D.; Turnau, J.; Ullrich, T.; Underwood, D. G.; Upsal, I.; Van Buren, G.; van Nieuwenhuizen, G.; Vandenbroucke, M.; Varma, R.; Vasconcelos, G. M. S.; Vasiliev, A. N.; Vertesi, R.; Videbæk, F.; Viyogi, Y. P.; Vokal, S.; Voloshin, S. A.; Vossen, A.; Wang, J. S.; Wang, X. L.; Wang, Y.; Wang, H.; Wang, F.; Wang, G.; Webb, G.; Webb, J. C.; Wen, L.; Westfall, G. D.; Wieman, H.; Wissink, S. W.; Witt, R.; Wu, Y. F.; Xiao, Z.; Xie, W.; Xin, K.; Xu, N.; Xu, Z.; Xu, H.; Xu, Y.; Xu, Q. H.; Yan, W.; Yang, Y.; Yang, C.; Yang, Y.; Ye, Z.; Yepes, P.; Yi, L.; Yip, K.; Yoo, I.-K.; Yu, N.; Zbroszczyk, H.; Zha, W.; Zhang, X. P.; Zhang, Z. P.; Zhang, J. B.; Zhang, J. L.; Zhang, Y.; Zhang, S.; Zhao, F.; Zhao, J.; Zhong, C.; Zhu, Y. H.; Zhu, X.; Zoulkarneeva, Y.; Zyzak, M.; STAR Collaboration
2016-08-01
Balance functions have been measured in terms of relative pseudorapidity (Δ η ) for charged particle pairs at the BNL Relativistic Heavy Ion Collider from Au + Au collisions at √{sNN}=7.7 GeV to 200 GeV using the STAR detector. These results are compared with balance functions measured at the CERN Large Hadron Collider from Pb + Pb collisions at √{sNN}=2.76 TeV by the ALICE Collaboration. The width of the balance function decreases as the collisions become more central and as the beam energy is increased. In contrast, the widths of the balance functions calculated using shuffled events show little dependence on centrality or beam energy and are larger than the observed widths. Balance function widths calculated using events generated by UrQMD are wider than the measured widths in central collisions and show little centrality dependence. The measured widths of the balance functions in central collisions are consistent with the delayed hadronization of a deconfined quark gluon plasma (QGP). The narrowing of the balance function in central collisions at √{sNN}=7.7 GeV implies that a QGP is still being created at this relatively low energy.
Energy Technology Data Exchange (ETDEWEB)
Kamph, Jerome Henri; Robinson, Darren; Wetter, Michael
2009-09-01
There is an increasing interest in the use of computer algorithms to identify combinations of parameters which optimise the energy performance of buildings. For such problems, the objective function can be multi-modal and needs to be approximated numerically using building energy simulation programs. As these programs contain iterative solution algorithms, they introduce discontinuities in the numerical approximation to the objective function. Metaheuristics often work well for such problems, but their convergence to a global optimum cannot be established formally. Moreover, different algorithms tend to be suited to particular classes of optimization problems. To shed light on this issue we compared the performance of two metaheuristics, the hybrid CMA-ES/HDE and the hybrid PSO/HJ, in minimizing standard benchmark functions and real-world building energy optimization problems of varying complexity. From this we find that the CMA-ES/HDE performs well on more complex objective functions, but that the PSO/HJ more consistently identifies the global minimum for simpler objective functions. Both identified similar values in the objective functions arising from energy simulations, but with different combinations of model parameters. This may suggest that the objective function is multi-modal. The algorithms also correctly identified some non-intuitive parameter combinations that were caused by a simplified control sequence of the building energy system that does not represent actual practice, further reinforcing their utility.
Sousa, Maria Inês; Amaral, Sandra; Tavares, Renata Santos; Paiva, Carla; Ramalho-Santos, João
2014-04-01
Literature regarding the effects of sildenafil citrate on sperm function remains controversial. In the present study, we specifically wanted to determine if mitochondrial dysfunction, namely membrane potential, reactive oxygen species production, and changes in energy content, are involved in in vitro sildenafil-induced alterations of human sperm function. Sperm samples of healthy men were incubated in the presence of 0.03, 0.3, and 3 μM sildenafil citrate in a phosphate buffered saline (PBS)-based medium for 2, 3, 12, and 24 hours. Sperm motility and viability were evaluated and mitochondrial function, i.e., mitochondrial membrane potential and mitochondrial superoxide production were assessed using flow-cytometry. Additionally, adenosine triphosphate (ATP) levels were determined by high performance liquid chromatography (HPLC) analysis. Results show a decrease in sperm motility correlated with the level of mitochondria-generated superoxide, without a visible effect on mitochondrial membrane potential or viability upon exposure to sildenafil. The effect on both motility and superoxide production was higher for the intermediate concentration of sildenafil (0.3 µM) indicating that the in vitro effects of sildenafil on human sperm do not vary linearly with drug concentration. Adenosine triphosphate levels also decreased following sildenafil exposure, but this decrease was only detected after a decrease in motility was already evident. These results suggest that along with the level of ATP and mitochondrial function other factors are involved in the early sildenafil-mediated decline in sperm motility. However, the further decrease in ATP levels and increase in mitochondria-generated reactive oxygen species after 24 hours of exposure might further contribute towards declining sperm motility.
Coronary wave energy: a novel predictor of functional recovery after myocardial infarction.
De Silva, Kalpa; Foster, Paul; Guilcher, Antoine; Bandara, Asela; Jogiya, Roy; Lockie, Tim; Chowiencyzk, Phil; Nagel, Eike; Marber, Michael; Redwood, Simon; Plein, Sven; Perera, Divaka
2013-04-01
Revascularization after acute coronary syndromes provides prognostic benefit, provided that the subtended myocardium is viable. The microcirculation and contractility of the subtended myocardium affect propagation of coronary flow, which can be characterized by wave intensity analysis. The study objective was to determine in acute coronary syndromes whether early wave intensity analysis-derived microcirculatory (backward) expansion wave energy predicts late viability, defined by functional recovery. Thirty-one patients (58±11 years) were enrolled after non-ST elevation myocardial infarction. Regional left ventricular function and late-gadolinium enhancement were assessed by cardiac magnetic resonance imaging, before and 3 months after revascularization. The backward-traveling (microcirculatory) expansion wave was derived from wave intensity analysis of phasic coronary pressure and velocity in the infarct-related artery, whereas mean values were used to calculate hyperemic microvascular resistance. Twelve-hour troponin T, left ventricular ejection fraction, and percentage late-gadolinium enhancement mass were 1.35±1.21 µg/L, 56±11%, and 8.4±6.0%, respectively. The infarct-related artery backward-traveling (microcirculatory) expansion wave was inversely correlated with late-gadolinium enhancement infarct mass (r=-0.81; Pwave threshold of 2.8 W m(-2) s(-2)×10(5) predicted functional recovery with sensitivity and specificity of 0.91 and 0.82 (AUC 0.88). Hyperemic microvascular resistance correlated with late-gadolinium enhancement mass (r=0.48; P=0.03) but not left ventricular recovery (r=-0.34; P=0.07). The microcirculation-derived backward expansion wave is a new index that correlates with the magnitude and location of infarction, which may allow for the prediction of functional myocardial recovery. Coronary wave intensity analysis may facilitate myocardial viability assessment during cardiac catheterization.
Flamigni, Lucia; Collin, Jean-Paul; Sauvage, Jean-Pierre
2008-07-01
In photosynthesis, sunlight energy is converted into a chemical potential by an electron transfer sequence that is started by an excited state and ultimately yields a long-lived charge-separated state. This process can be reproduced by carefully designed multicomponent artificial arrays of three or more components, and the stored energy can be used to oxidize or reduce molecules in solution, to inject electrons or holes, or to create an electron flow. Therefore, the process is important both for artificial-photosynthesis research and for photovoltaic and optoelectronic applications. Molecular arrays for photoinduced charge separation often use chromophores that resemble the natural ones. However, new synthetic components, including transition metal complexes, have had some success. This Account discusses the use of bis-terpyridine (tpy) metal complexes as assembling and functional units of such multicomponent arrays. M(tpy)2(n+) complexes have the advantage of yielding linear arrays with unambiguous geometry. Originally, Ru(tpy)2(2+) and Os(tpy)2(2+) were used as photosensitizers in triads containing typical organic donors and acceptors. However, it soon became evident that the relatively low excited state of these complexes could act as an energy drain of the excited state of the photosensitizer and, thus, seriously compete with charge separation. A new metal complex that preserved the favorable tpy geometry and yet had a higher energy level was needed. We identified Ir(tpy)2(3+), which displayed a higher energy level, a more facile reduction that favored charge separation, a longer excited-state lifetime, and strong spectroscopic features that were useful for the identification of intermediates. Ir(tpy)2(3+) was used in arrays with electron-donating gold porphyrin and electron-accepting free-base porphyrins. A judicious change of the free-base porphyrin photosensitizer with zinc porphyrin allowed us to shape the photoreactivity and led to charge separation with
Green energy facilitated? The uncertain function of the global environment facility
International Nuclear Information System (INIS)
Young, Z.; Boehmer-Christiansen, S.
1998-01-01
The GEF remains the interim operating entity of the financial mechanism, the aid provider, for the Climate Change Convention (FCCC); It had 1.6 billion dollars to spend between 1994 and 1997 on the 'incremental costs' of implementing UN environmental conventions in eligible countries. The paper describes how this multilateral fund has functioned so far in the energy-environment arena, analyzing its governance and policies, decision-making criteria, project cycle and strategies for monitoring and evaluation. Through the patterns of GEF assistance to climate change related science, technologies and institutions, we explore the origins and wider purposes of the entity and in the process illuminate some assumptions and principles underlying the work of the GEF Secretariat and associated bureaucracies. What can realistically be expected should GEF become a more permanent fund for 'global environmental benefits' after current negotiations for its second replenishment? (author)
TL response of LiF: Mg, Cu, P dosemeters in function of the photon energy
International Nuclear Information System (INIS)
Gonzalez, P.R.; Azorin, J.; Furetta, C.
2005-01-01
In this work the obtained results of studying the response of dosemeters of LiF: Mg, Cu, P + Ptfe, developed in the ININ, commercial dosemeters GR200A (LiF: Mg, Cu, P) of chinese manufacture and TLD-100 (LiF: Mg, Ti) US are presented, when irradiating them with X rays 16, 24, 34.5, 42, 100 and 145 keV of effective energy, with gamma rays of 662 keV ( 137 Cs) and 1252 keV ( 60 Co). The results are presented in function of the sensitivity that the dosemeters showed normalized to gamma radiation of 60 Co. It was appreciated that the dosemeters more equivalent to the tissue, they were those of LiF: Mg, Cu, P + Ptfe, while the less equivalent ones were the TLD-100. (Author)
Low energy cooling of the White Tower, functioning as a contemporary museum
Energy Technology Data Exchange (ETDEWEB)
Papadopoulos, A.M.; Avgelis, A.; Anastaselos, D. [Laboratory of Heat Transfer and Environmental Engineering, Department of Mechanical Engineering, School of Engineering, Aristotle University of Thessaloniki, Thessaloniki (Greece)
2008-07-01
Historical buildings are of significance not only because they preserve the cultural heritage of nations but also because of their representative character. However, as buildings they not necessarily provide satisfactory comfort and health conditions, despite the fact that they can be high-energy consumers. The Museum of Byzantine Culture in Thessaloniki has decided to convert the White Tower, a six-floor fortress dating back to the 15th century, into a contemporary city museum with means of audiovisual, virtual and information technologies. A study has been carried out in 2005-2006 to determine the possibilities, given the restrictions applying, to implement measures in order to establish and maintain satisfactory thermal comfort and indoor air quality conditions in the White Tower, whilst ensuring its unobstructed function as a contemporary city museum. The measurements and simulations carried out, together with the resulting suggested interventions are discussed in this paper. (author)
Electron and ion energy distribution functions in slide-away regime of TRIAM-1 tokamak
Energy Technology Data Exchange (ETDEWEB)
Nakamura, Kazuo; Satoh, Takemichi; Toi, Kazuo; Hiraki, Naoji; Nakamura, Yukio; Itoh, Satoshi
1983-02-01
The plasma properties, and the electron and ion energy distribution functions in particular, are studied in the slide-away regime of the TRIAM-1 tokamak, with the streaming parameter averaged over the plasma cross-section
DEFF Research Database (Denmark)
Xu, Yu
Continuous hydrothermal flow synthesis (CHFS) was used to prepare functional oxide nanoparticles. Materials synthesized include NiO, Y-doped ZrO2, Gd-doped CeO2, LaCrO3 and Ni-substituted CoFe2O4. These types of oxides can be applied in several energy conversion devices, e.g. as active materials...... as materials are continuously produced, and the technology can be scaled-up to an industrial-relevant production capacity. The thesis starts with investigating the most appropriate mixer design for a novel two-stage reactor by computational fluid dynamics modelling. On basis of the modelling results, a two......, dense continuous layers (
Towards the improvement of spin-isospin properties in nuclear energy density functionals
International Nuclear Information System (INIS)
Roca-Maza, X.; Colò, G.; Liang, H. Z.; Sagawa, H.; Meng, J.; Ring, P.; Zhao, P. W.
2016-01-01
We address the problem of improving existing nuclear Energy Density Functionals (EDFs) in the spin-isospin channel. For that, we propose two different ways. The first one is to carefully take into account in the fitting protocol some of the key ground state properties for an accurate description of the most studied spin-isospin resonances: the Gamow-Teller Resonance (GTR) [1]. The second consists in providing a strategy to build local covariant EDF keeping the main features from their non-local counterparts [2]. The RHF model based on a Lagrangian where heavy mesons carry the nuclear effective interaction have been shown to be successful in the description of spin-isospin resonances [3]. (paper)
International Nuclear Information System (INIS)
Bobin, J.L.
1996-01-01
Object of sciences and technologies, energy plays a major part in economics and relations between nations. Jean-Louis Bobin, physicist, analyses the relations between man and energy and wonders about fears that delivers nowadays technologies bound to nuclear energy and about the fear of a possible shortage of energy resources. (N.C.). 17 refs., 14 figs., 2 tabs
Non-Maxwellian electron energy probability functions in the plume of a SPT-100 Hall thruster
Giono, G.; Gudmundsson, J. T.; Ivchenko, N.; Mazouffre, S.; Dannenmayer, K.; Loubère, D.; Popelier, L.; Merino, M.; Olentšenko, G.
2018-01-01
We present measurements of the electron density, the effective electron temperature, the plasma potential, and the electron energy probability function (EEPF) in the plume of a 1.5 kW-class SPT-100 Hall thruster, derived from cylindrical Langmuir probe measurements. The measurements were taken on the plume axis at distances between 550 and 1550 mm from the thruster exit plane, and at different angles from the plume axis at 550 mm for three operating points of the thruster, characterized by different discharge voltages and mass flow rates. The bulk of the electron population can be approximated as a Maxwellian distribution, but the measured distributions were seen to decline faster at higher energy. The measured EEPFs were best modelled with a general EEPF with an exponent α between 1.2 and 1.5, and their axial and angular characteristics were studied for the different operating points of the thruster. As a result, the exponent α from the fitted distribution was seen to be almost constant as a function of the axial distance along the plume, as well as across the angles. However, the exponent α was seen to be affected by the mass flow rate, suggesting a possible relationship with the collision rate, especially close to the thruster exit. The ratio of the specific heats, the γ factor, between the measured plasma parameters was found to be lower than the adiabatic value of 5/3 for each of the thruster settings, indicating the existence of non-trivial kinetic heat fluxes in the near collisionless plume. These results are intended to be used as input and/or testing properties for plume expansion models in further work.
A joint probability density function of wind speed and direction for wind energy analysis
International Nuclear Information System (INIS)
Carta, Jose A.; Ramirez, Penelope; Bueno, Celia
2008-01-01
A very flexible joint probability density function of wind speed and direction is presented in this paper for use in wind energy analysis. A method that enables angular-linear distributions to be obtained with specified marginal distributions has been used for this purpose. For the marginal distribution of wind speed we use a singly truncated from below Normal-Weibull mixture distribution. The marginal distribution of wind direction comprises a finite mixture of von Mises distributions. The proposed model is applied in this paper to wind direction and wind speed hourly data recorded at several weather stations located in the Canary Islands (Spain). The suitability of the distributions is judged from the coefficient of determination R 2 . The conclusions reached are that the joint distribution proposed in this paper: (a) can represent unimodal, bimodal and bitangential wind speed frequency distributions, (b) takes into account the frequency of null winds, (c) represents the wind direction regimes in zones with several modes or prevailing wind directions, (d) takes into account the correlation between wind speeds and its directions. It can therefore be used in several tasks involved in the evaluation process of the wind resources available at a potential site. We also conclude that, in the case of the Canary Islands, the proposed model provides better fits in all the cases analysed than those obtained with the models used in the specialised literature on wind energy
Tantakitti, Faifan
Supramolecular chemistry is a powerful tool to create a material of a defined structure with tunable properties. This strategy has led to catalytically active, bioactive, and environment-responsive materials, among others, that are valuable in applications ranging from sensor technology to energy and medicine. Supramolecular polymers formed by peptide amphiphiles (PAs) have been especially relevant in tissue regeneration due to their ability to form biocompatible structures and mimic many important signaling molecules in biology. These supramolecular polymers can form nanofibers that create networks which mimic natural extracellular matrices. PA materials have been shown to induce growth of blood vessels, bone, cartilage, and nervous tissue, among others. The work described in this thesis not only studied the relationship between molecular structure and functions of PA assemblies, but also uncovered a powerful link between the energy landscape of their supramolecular self-assembly and the ability of PA materials to interact with cells. In chapter 2, it is argued that fabricating fibrous nanostructures with defined mechanical properties and decoration with bioactive molecules is not sufficient to create a material that can effectively communicate with cells. By systemically placing the fibronectin-derived RGDS epitope at increasing distances from the surface of PA nanofibers through a linker of one to five glycine residues, integrin-mediated RGDS signaling was enhanced. The results suggested that the spatial presentation of an epitope on PA nanofibers strongly influences the bioactivity of the PA substrates. In further improving functionality of a PA-based scaffold to effectively direct cell growth and differentiation, chapter 3 explored the use of a cell microcarrier to compartmentalize and simultaneously tune insoluble and soluble signals in a single matrix. PA nanofibers were incorporated at the surface of the microcarrier in order to promote cell adhesion, while
High solids emulsions produced by ultrasound as a function of energy density.
Consoli, Larissa; de Figueiredo Furtado, Guilherme; da Cunha, Rosiane Lopes; Hubinger, Míriam Dupas
2017-09-01
The use of emulsifying methods is frequently required before spray drying food ingredients, where using high concentration of solids increases the drying process yield. In this work, we used ultrasound to obtain kinetically stable palm oil-in-water emulsions with 30g solids/100g of emulsion. Sodium caseinate, maltodextrin and dried glucose syrup were used as stabilizing agents. Sonication time of 3, 7 and 11min were evaluated at power of 72, 105 and 148W (which represents 50%, 75% and 100% of power amplitude in relation to the nominal power of the equipment). Energy density required for each assay was calculated. Emulsions were characterized for droplets mean diameter and size distribution, optical microscopy, confocal microscopy, ζ-potential, creaming index (CI) and rheological behavior. Emulsions presented bimodal size distribution, with D [3,2] ranging from 0.7 to 1.4μm and CI between 5% and 12%, being these parameters inversely proportional to sonication time and power, but with a visual kinetically stabilization after the treatment at 148W at 7min sonication. D [3,2] showed to depend of energy density as a power function. Sonication presented as an effective method to be integrated to spray drying when emulsification is needed before the drying process. Copyright © 2016 Elsevier B.V. All rights reserved.
Energy-containing beverages: reproductive hormones and ovarian function in the BioCycle Study123
Schliep, Karen C; Mumford, Sunni L; Pollack, Anna Z; Perkins, Neil J; Ye, Aijun; Zhang, Cuilin J; Stanford, Joseph B; Porucznik, Christina A; Hammoud, Ahmad O; Wactawski-Wende, Jean
2013-01-01
Background: Energy-containing beverages are widely consumed among premenopausal women, but their association with reproductive hormones is not well understood. Objective: The objective was to assess the association of energy-containing beverages, added sugars, and total fructose intake with reproductive hormones among ovulatory cycles and sporadic anovulation in healthy premenopausal women. Design: Women (n = 259) in the BioCycle Study were followed for up to 2 menstrual cycles; they provided fasting blood specimens during up to 8 visits/cycle and four 24-h dietary recalls/cycle. Results: Women who consumed ≥1 cup (1 cup = 237 mL) sweetened soda/d had 16.3% higher estradiol concentrations compared with women who consumed less sweetened soda (86.5 pg/mL compared with 74.4 pg/mL, P = 0.01) after adjustment for age, BMI, race, dietary factors, and physical activity. Similarly elevated estradiol concentrations were found for ≥1 cup cola/d and noncola soda intake. Neither artificially sweetened soda nor fruit juice intake ≥1 cup/d was significantly associated with reproductive hormones. Added sugar above the average US woman's intake (≥73.2 g/d) or above the 66th percentile in total fructose intake (≥41.5 g/d) was associated with significantly elevated estradiol but not consistently across all models. No associations were found between beverages, added sugars, or total fructose intake and anovulation after multivariate adjustment. Conclusions: Even at moderate consumption amounts, sweetened soda is associated with elevated follicular estradiol concentrations among premenopausal women but does not appear to affect ovulatory function. Further research into the mechanism driving the association between energy-containing beverages and reproductive hormones, and its potential implications for women's health, is warranted. PMID:23364018
Energy-containing beverages: reproductive hormones and ovarian function in the BioCycle Study.
Schliep, Karen C; Schisterman, Enrique F; Mumford, Sunni L; Pollack, Anna Z; Perkins, Neil J; Ye, Aijun; Zhang, Cuilin J; Stanford, Joseph B; Porucznik, Christina A; Hammoud, Ahmad O; Wactawski-Wende, Jean
2013-03-01
Energy-containing beverages are widely consumed among premenopausal women, but their association with reproductive hormones is not well understood. The objective was to assess the association of energy-containing beverages, added sugars, and total fructose intake with reproductive hormones among ovulatory cycles and sporadic anovulation in healthy premenopausal women. Women (n = 259) in the BioCycle Study were followed for up to 2 menstrual cycles; they provided fasting blood specimens during up to 8 visits/cycle and four 24-h dietary recalls/cycle. Women who consumed ≥1 cup (1 cup = 237 mL) sweetened soda/d had 16.3% higher estradiol concentrations compared with women who consumed less sweetened soda (86.5 pg/mL compared with 74.4 pg/mL, P = 0.01) after adjustment for age, BMI, race, dietary factors, and physical activity. Similarly elevated estradiol concentrations were found for ≥1 cup cola/d and noncola soda intake. Neither artificially sweetened soda nor fruit juice intake ≥1 cup/d was significantly associated with reproductive hormones. Added sugar above the average US woman's intake (≥73.2 g/d) or above the 66th percentile in total fructose intake (≥41.5 g/d) was associated with significantly elevated estradiol but not consistently across all models. No associations were found between beverages, added sugars, or total fructose intake and anovulation after multivariate adjustment. Even at moderate consumption amounts, sweetened soda is associated with elevated follicular estradiol concentrations among premenopausal women but does not appear to affect ovulatory function. Further research into the mechanism driving the association between energy-containing beverages and reproductive hormones, and its potential implications for women's health, is warranted.
Nii, Maria; Maeda, Keisuke; Wakabayashi, Hidetaka; Nishioka, Shinta; Tanaka, Atsuko
2016-01-01
Malnutrition affects the activities of daily living (ADLs) in convalescent patients with cerebrovascular disorders. We investigated the relationship between nutritional improvement, energy intake at admission, and recovery of ADLs. We evaluated 67 patients with cerebrovascular disorders admitted to our rehabilitation hospital between April 2013 and April 2015. These patients received interventions from the rehabilitation nutritional support team according to the following criteria: weight loss of 2 kg or more and body mass index of 19 kg/m(2) or lower. Exclusion criteria included a body mass index of 25 kg/m(2) or higher, duration of intervention of less than 14 days, or transfer to an acute care hospital because of clinical deterioration. We assessed nutritional status using the Geriatric Nutritional Risk Index (GNRI) and ADL using the Functional Independence Measure (FIM) score, FIM gain, and FIM efficiency. The mean age of the patients was 78.7 ± 8.0 years. The numbers of patients in each category of cerebrovascular disorder were 39 with cerebral infarction, 16 with intracerebral hemorrhage, 8 with subarachnoid hemorrhage, and 4 others. Compared with the counterpart group, the group with an improvement in GNRI had a greater gain in FIM (median 17 and 20, respectively; P = .036) and a higher FIM efficiency (.14 and .22, respectively; P = .020). Multivariate stepwise regression analysis showed that an improvement in GNRI, increasing energy intake at admission, and intracerebral hemorrhage were associated independently with greater FIM efficiency. This study suggested that nutritional improvement and energy intake at admission are associated with recovery of ADL after cerebrovascular disorders. Copyright © 2015 National Stroke Association. Published by Elsevier Inc. All rights reserved.
Energy dependent charge spread function in a dedicated synchrotron beam pnCCD detector
International Nuclear Information System (INIS)
Yousef, Hazem
2011-01-01
A scan on the pixel edges is the method which is used to resolve the electron cloud size in the pixel array of the pnCCD detector. The EDR synchrotron radiation in BESSY is the source of the X-ray photons which are used in the scans. The radius of the electron cloud as a function of the impinging photon energy is analyzed. The angle of incidence of the X-ray beam is employed in the measurements. The measurements are validated by the numerical simulation models. The inclined X-ray track leads to distribute the electron clouds in a certain number of pixels according to the incident angle of the X-ray beam. The pixels detect different electron clouds according to their generation position in the detector bulk. A collimated X-ray beam of 12.14 keV is used in the measurements with 30 and 40 entrance angles. It is shown that the two factors that leads to expand the electron clouds namely the diffusion and the mutual electrostatic repulsion can be separated from the measured electron clouds. It is noticed as well that the influence of the mutual electrostatic repulsion dominates the cloud expansion over the diffusion process in the collection time of the detector. The perpendicular X-ray track leads to determine the average radius of the electron cloud per photon energy. The results show that the size of the electron clouds (RMS) in the energy range of [5.0-21.6] keV is smaller than the pixel size. (orig.)
Threshold energy dependence as a function of potential strength and the nonexistence of bound states
International Nuclear Information System (INIS)
Aronson, I.; Kleinman, C.J.; Spruch, L.
1975-01-01
The difficulty in attempting to prove that a given set of particles cannot form a bound state is the absence of a margin of error; the possibility of a bound state of arbitrarily small binding energy must be ruled out. At the sacrifice of rigor, one can hope to bypass the difficulty by studying the ground-state energy E(lambda) associated with H(lambda) identical with H/sub true/ + lambda/sub ν/, where H/sub true/ is the true Hamiltonian, ν is an artificial attractive potential, and lambda greater than 0. E(lambda) can be estimated via a Rayleigh-Ritz calculation. If H/sub true/ falls just short of being able to support a bound state, H(lambda) for lambda ''not too small'' will support a bound state of some significant binding. A margin of error is thereby created; the inability to find a bound state for lambda ''not too small'' suggests not only that H(lambda) can support at best a weakly bound state but that H/sub true/ cannot support a bound state at all. To give the argument real substance, one studies E(lambda) in the neighborhood of lambda = lambda 0 , the (unknown) smallest value for lambda for which H(lambda) can support a bound state. A comparison of E(lambda) determined numerically with the form of E(lambda) obtained with the use of a crude bound-state wave function in the Feynman theorem gives a rough self-consistency check. One thereby obtains a believable lower bound on the energy of a possible bound state of H/sub true/ or a believable argument that no such bound state exists. The method is applied to the triplet state of H -
Energy dependent charge spread function in a dedicated synchrotron beam pnCCD detector
Energy Technology Data Exchange (ETDEWEB)
Yousef, Hazem
2011-05-20
A scan on the pixel edges is the method which is used to resolve the electron cloud size in the pixel array of the pnCCD detector. The EDR synchrotron radiation in BESSY is the source of the X-ray photons which are used in the scans. The radius of the electron cloud as a function of the impinging photon energy is analyzed. The angle of incidence of the X-ray beam is employed in the measurements. The measurements are validated by the numerical simulation models. The inclined X-ray track leads to distribute the electron clouds in a certain number of pixels according to the incident angle of the X-ray beam. The pixels detect different electron clouds according to their generation position in the detector bulk. A collimated X-ray beam of 12.14 keV is used in the measurements with 30 and 40 entrance angles. It is shown that the two factors that leads to expand the electron clouds namely the diffusion and the mutual electrostatic repulsion can be separated from the measured electron clouds. It is noticed as well that the influence of the mutual electrostatic repulsion dominates the cloud expansion over the diffusion process in the collection time of the detector. The perpendicular X-ray track leads to determine the average radius of the electron cloud per photon energy. The results show that the size of the electron clouds (RMS) in the energy range of [5.0-21.6] keV is smaller than the pixel size. (orig.)
Hocine, Nora; Meignan, Michel; Masset, Hélène
2018-04-01
To better understand the risks of cumulative medical X-ray investigations and the possible causal role of contrast agent on the coronary artery wall, the correlation between iodinated contrast media and the increase of energy deposited in the coronary artery lumen as a function of iodine concentration and photon energy is investigated. The calculations of energy deposition have been performed using Monte Carlo (MC) simulation codes, namely PENetration and Energy LOss of Positrons and Electrons (PENELOPE) and Monte Carlo N-Particle eXtended (MCNPX). Exposure of a cylinder phantom, artery and a metal stent (AISI 316L) to several X-ray photon beams were simulated. For the energies used in cardiac imaging the energy deposited in the coronary artery lumen increases with the quantity of iodine. Monte Carlo calculations indicate a strong dependence of the energy enhancement factor (EEF) on photon energy and iodine concentration. The maximum value of EEF is equal to 25; this factor is showed for 83 keV and for 400 mg Iodine/mL. No significant impact of the stent is observed on the absorbed dose in the artery for incident X-ray beams with mean energies of 44, 48, 52 and 55 keV. A strong correlation was shown between the increase in the concentration of iodine and the energy deposited in the coronary artery lumen for the energies used in cardiac imaging and over the energy range between 44 and 55 keV. The data provided by this study could be useful for creating new medical imaging protocols to obtain better diagnostic information with a lower level of radiation exposure.
Foland, Andrew Dean
2007-01-01
Energy is the central concept of physics. Unable to be created or destroyed but transformable from one form to another, energy ultimately determines what is and isn''t possible in our universe. This book gives readers an appreciation for the limits of energy and the quantities of energy in the world around them. This fascinating book explores the major forms of energy: kinetic, potential, electrical, chemical, thermal, and nuclear.
International Nuclear Information System (INIS)
Attarian Shandiz, M.; Gauvin, R.
2014-01-01
The temperature and pressure dependency of the volume plasmon energy of solids was investigated by density functional theory calculations. The volume change of crystal is the major factor responsible for the variation of valence electron density and plasmon energy in the free electron model. Hence, to introduce the effect of temperature and pressure for the density functional theory calculations of plasmon energy, the temperature and pressure dependency of lattice parameter was used. Also, by combination of the free electron model and the equation of state based on the pseudo-spinodal approach, the temperature and pressure dependency of the plasmon energy was modeled. The suggested model is in good agreement with the results of density functional theory calculations and available experimental data for elements with the free electron behavior.
Headland, Michelle L; Clifton, Peter M; Keogh, Jennifer B
2018-06-04
Intermittent energy restriction is a popular alternative to daily energy restriction for weight loss; however, it is unknown if endothelial function, a risk factor for cardiovascular disease, is altered by periods of severe energy restriction. The objective of the study was to determine the impact of two consecutive very low energy intake days, which is the core component of the 5:2 intermittent energy restriction diet strategy, on endothelial function compared to consecutive ad libitum eating days. The secondary objective was to explore the effects of these dietary conditions on fasting glucose concentrations. This was a 4-week randomized, single-blinded, crossover study of 35 participants. Participants consumed a very low energy diet (500 calories for women, 600 calories for men) on two consecutive days per week and 5 days of habitual eating. In weeks 3 and 4 of the trial, participants had measurements of flow mediated dilatation (FMD) and blood samples taken following either 2 habitual eating days or 2 energy restricted days in a randomized order. FMD values were not different after the two eating states (8.6% vs. 8.3%, p = 0.7). All other outcome variables were unchanged. Endothelial function, as measured by flow mediated dilatation, was not altered by two consecutive very low energy intake days. Further investigations assessing the impact in specific population groups as well as different testing conditions would be beneficial.
Directory of Open Access Journals (Sweden)
Michelle L. Headland
2018-06-01
Full Text Available Intermittent energy restriction is a popular alternative to daily energy restriction for weight loss; however, it is unknown if endothelial function, a risk factor for cardiovascular disease, is altered by periods of severe energy restriction. The objective of the study was to determine the impact of two consecutive very low energy intake days, which is the core component of the 5:2 intermittent energy restriction diet strategy, on endothelial function compared to consecutive ad libitum eating days. The secondary objective was to explore the effects of these dietary conditions on fasting glucose concentrations. This was a 4-week randomized, single-blinded, crossover study of 35 participants. Participants consumed a very low energy diet (500 calories for women, 600 calories for men on two consecutive days per week and 5 days of habitual eating. In weeks 3 and 4 of the trial, participants had measurements of flow mediated dilatation (FMD and blood samples taken following either 2 habitual eating days or 2 energy restricted days in a randomized order. FMD values were not different after the two eating states (8.6% vs. 8.3%, p = 0.7. All other outcome variables were unchanged. Endothelial function, as measured by flow mediated dilatation, was not altered by two consecutive very low energy intake days. Further investigations assessing the impact in specific population groups as well as different testing conditions would be beneficial.
The Development of Functional Mesocrystals for Energy Harvesting, Storage, and Conversion.
Zhang, Peng; Tachikawa, Takashi; Fujitsuka, Mamoru; Majima, Tetsuro
2018-04-25
Higher-ordered semiconductors have attracted extensive research interest as an adopted engineering for active solar energy harvesting, storage, and conversion. It is well-known that the effective separation and anisotropic migration of photogenerated charges are the basic driven force required for superior efficiency. However, the morphology and stoichiometric variation of these semiconductors play essential roles in their physicochemical properties of bulk and surface, especially for efficient interparticle or interfacial charge transfer. To this point, the strategy of controlling the topotactic transformation toward superstructures with optimized functionality is preferable for a wide range of optoelectronic and catalytic engineering applications. In this Minireview, we provide an overview of the crystal orientation, synthetic engineering, functional applications, and spatial and temporal charge dynamics in TiO 2 mesocrystals and others. The viewpoint of in-depth understanding of the structure-related kinetics would offer an opportunity for design of versatile mesocrystal semiconductors sought-after for potential applications. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.
Ruiz, Rafael O.; Meruane, Viviana
2017-06-01
The goal of this work is to describe a framework to propagate uncertainties in piezoelectric energy harvesters (PEHs). These uncertainties are related to the incomplete knowledge of the model parameters. The framework presented could be employed to conduct prior robust stochastic predictions. The prior analysis assumes a known probability density function for the uncertain variables and propagates the uncertainties to the output voltage. The framework is particularized to evaluate the behavior of the frequency response functions (FRFs) in PEHs, while its implementation is illustrated by the use of different unimorph and bimorph PEHs subjected to different scenarios: free of uncertainties, common uncertainties, and uncertainties as a product of imperfect clamping. The common variability associated with the PEH parameters are tabulated and reported. A global sensitivity analysis is conducted to identify the Sobol indices. Results indicate that the elastic modulus, density, and thickness of the piezoelectric layer are the most relevant parameters of the output variability. The importance of including the model parameter uncertainties in the estimation of the FRFs is revealed. In this sense, the present framework constitutes a powerful tool in the robust design and prediction of PEH performance.
Influence of using nanoobjects as filler on functionality-based energy use of nanocomposites
Energy Technology Data Exchange (ETDEWEB)
Roes, A. L., E-mail: a.l.roes@uu.nl; Tabak, L. B.; Shen, L.; Nieuwlaar, E.; Patel, M. K. [Utrecht University, Copernicus Institute, Department of Science, Technology and Society (Netherlands)
2010-08-15
The goal of our study was to investigate the potential benefits of reinforcing polymer matrices with nanoobjects for structural applications by looking at both the mechanical properties and environmental impacts. For determining the mechanical properties, we applied the material indices defined by Ashby for stiffness and strength. For the calculation of environmental impacts, we applied the life cycle assessment methodology, focusing on non-renewable energy use (NREU). NREU has shown to be a good indicator also for other environmental impacts. We then divided the NREU by the appropriate Ashby index to obtain the 'functionality-based NREU'. We studied 23 different nanocomposites, based on thermoplastic and thermosetting polymer matrices and organophilic montmorillonite, silica, carbon nanotubes (single-walled and multiwalled) and calcium carbonate as filler. For 17 of these, we saw a decrease of the functionality-based NREU with increasing filler content. We draw the conclusion that the use of nanoobjects as filler can have benefits from both an environmental point of view and with respect to mechanical properties.
Strategies for the design of functional MOFs: addressing energy-intensive separations
Eddaoudi, Mohamed
2017-12-19
Metal Organic Frameworks (MOFs) are a promising class of crystalline solid-state materials amenable to tailoring their porosity and functionality towards various applications. MOF reticular chemistry using the Molecular Building Block (MBB) approach offers potential to construct robust made-to-order MOFs, where desired structural and geometrical information are incorporated into the building blocks prior to the assembly process. We will discuss two recently implemented conceptual approaches facilitating the design and deliberate construction of metal–organic frameworks (MOFs), namely supermolecular building block (SBB) and supermolecular building layer (SBL) approaches. Additionally, the concept of net-coded building units (net-cBUs), where precise embedded geometrical information codes uniquely and matchlessly a selected net, as a compelling route for the rational design of MOFs will be presented. Our progress in the development of functional metal-organic frameworks (MOFs) to address some energy-intensive separations will be discussed. Namely, the successful practice of reticular chemistry affording the fabrication of various stable MOFs with controlled pore-aperture size and allowing effective separation of various gas or vapors pairs.
Protein-Energy Malnutrition Causes Deficits in Motor Function in Adult Male Rats.
Alaverdashvili, Mariam; Li, Xue; Paterson, Phyllis G
2015-11-01
Adult protein-energy malnutrition (PEM) often occurs in combination with neurological disorders affecting hand use and walking ability. The independent effects of PEM on motor function are not well characterized and may be obscured by these comorbidities. Our goal was to undertake a comprehensive evaluation of sensorimotor function with the onset and progression of PEM in an adult male rat model. In Expt. 1 and Expt. 2, male Sprague-Dawley rats (14-15 wk old) were assigned ad libitum access for 4 wk to normal-protein (NP) or low-protein (LP) diets containing 12.5% and 0.5% protein, respectively. Expt. 1 assessed muscle strength, balance, and skilled walking ability on days 2, 8, and 27 by bar-holding, cylinder, and horizontal ladder walking tasks, respectively. In addition to food intake and body weight, nutritional status was determined on days 3, 9, and 28 by serum acute-phase reactant and corticosterone concentrations and liver lipids. Expt. 2 addressed the effect of an LP diet on hindlimb muscle size. PEM evolved over time in rats consuming the LP diet. Total food intake decreased by 24% compared with the NP group. On day 28, body weight and serum albumin decreased by 31% and 26%, respectively, and serum α2-macroglobulin increased by 445% (P malnutrition. This model can be used in combination with disease models of sensorimotor deficits to examine the interactions between nutritional status, other treatments, and disease progression. © 2015 American Society for Nutrition.
Directory of Open Access Journals (Sweden)
Dlamini Thembelihle
2017-01-01
Full Text Available Future mobile networks (MNs are required to be flexible with minimal infrastructure complexity, unlike current ones that rely on proprietary network elements to offer their services. Moreover, they are expected to make use of renewable energy to decrease their carbon footprint and of virtualization technologies for improved adaptability and flexibility, thus resulting in green and self-organized systems. In this article, we discuss the application of software defined networking (SDN and network function virtualization (NFV technologies towards softwarization of the mobile network functions, taking into account different architectural proposals. In addition, we elaborate on whether mobile edge computing (MEC, a new architectural concept that uses NFV techniques, can enhance communication in 5G cellular networks, reducing latency due to its proximity deployment. Besides discussing existing techniques, expounding their pros and cons and comparing state-of-the-art architectural proposals, we examine the role of machine learning and data mining tools, analyzing their use within fully SDN- and NFV-enabled mobile systems. Finally, we outline the challenges and the open issues related to evolved packet core (EPC and MEC architectures.
Wei, J. Q.; Cong, Y. C.; Xiao, M. Q.
2018-05-01
As renewable energies are increasingly integrated into power systems, there is increasing interest in stochastic analysis of power systems.Better techniques should be developed to account for the uncertainty caused by penetration of renewables and consequently analyse its impacts on stochastic stability of power systems. In this paper, the Stochastic Differential Equations (SDEs) are used to represent the evolutionary behaviour of the power systems. The stationary Probability Density Function (PDF) solution to SDEs modelling power systems excited by Gaussian white noise is analysed. Subjected to such random excitation, the Joint Probability Density Function (JPDF) solution to the phase angle and angular velocity is governed by the generalized Fokker-Planck-Kolmogorov (FPK) equation. To solve this equation, the numerical method is adopted. Special measure is taken such that the generalized FPK equation is satisfied in the average sense of integration with the assumed PDF. Both weak and strong intensities of the stochastic excitations are considered in a single machine infinite bus power system. The numerical analysis has the same result as the one given by the Monte Carlo simulation. Potential studies on stochastic behaviour of multi-machine power systems with random excitations are discussed at the end.
Anderson, Julie A; Tschumper, Gregory S
2006-06-08
Ten stationary points on the water dimer potential energy surface have been examined with ten density functional methods (X3LYP, B3LYP, B971, B98, MPWLYP, PBE1PBE, PBE, MPW1K, B3P86, and BHandHLYP). Geometry optimizations and vibrational frequency calculations were carried out with the TZ2P(f,d)+dif basis set. All ten of the density functionals correctly describe the relative energies of the ten stationary points. However, correctly describing the curvature of the potential energy surface is far more difficult. Only one functional (BHandHLYP) reproduces the number of imaginary frequencies from CCSD(T) calculations. The other nine density functionals fail to correctly characterize the nature of at least one of the ten (H(2)O)(2) stationary points studied here.
Werner, Jan; Sfakianakis, Nikolaos; Rendall, Alan D; Griebeler, Eva Maria
2018-05-07
Ectothermic and endothermic vertebrates differ not only in their source of body temperature (environment vs. metabolism), but also in growth patterns, in timing of sexual maturation within life, and energy intake functions. Here, we present a mathematical model applicable to ectothermic and endothermic vertebrates. It is designed to test whether differences in the timing of sexual maturation within an animal's life (age at which sexual maturity is reached vs. longevity) together with its ontogenetic gain in body mass (growth curve) can predict the energy intake throughout the animal's life (food intake curve) and can explain differences in energy partitioning (between growth, reproduction, heat production and maintenance, with the latter subsuming any other additional task requiring energy) between ectothermic and endothermic vertebrates. With our model we calculated from the growth curves and ages at which species reached sexual maturity energy intake functions and energy partitioning for five ectothermic and seven endothermic vertebrate species. We show that our model produces energy intake patterns and distributions as observed in ectothermic and endothermic species. Our results comply consistently with some empirical studies that in endothermic species, like birds and mammals, energy is used for heat production instead of growth, and with a hypothesis on the evolution of endothermy in amniotes published by us before. Our model offers an explanation on known differences in absolute energy intake between ectothermic fish and reptiles and endothermic birds and mammals. From a mathematical perspective, the model comes in two equivalent formulations, a differential and an integral one. It is derived from a discrete level approach, and it is shown to be well-posed and to attain a unique solution for (almost) every parameter set. Numerically, the integral formulation of the model is considered as an inverse problem with unknown parameters that are estimated using a
Allaway, Heather C M; Southmayd, Emily A; De Souza, Mary Jane
2016-02-01
An energy deficiency is the result of inadequate energy intake relative to high energy expenditure. Often observed with the development of an energy deficiency is a high drive for thinness, dietary restraint, and weight and shape concerns in association with eating behaviors. At a basic physiologic level, a chronic energy deficiency promotes compensatory mechanisms to conserve fuel for vital physiologic function. Alterations have been documented in resting energy expenditure (REE) and metabolic hormones. Observed metabolic alterations include nutritionally acquired growth hormone resistance and reduced insulin-like growth factor-1 (IGF-1) concentrations; hypercortisolemia; increased ghrelin, peptide YY, and adiponectin; and decreased leptin, triiodothyronine, and kisspeptin. The cumulative effect of the energetic and metabolic alterations is a suppression of the hypothalamic-pituitary-ovarian axis. Gonadotropin releasing hormone secretion is decreased with consequent suppression of luteinizing hormone and follicle stimulating hormone release. Alterations in hypothalamic-pituitary secretion alters the production of estrogen and progesterone resulting in subclinical or clinical menstrual dysfunction.
Hasan, E.; Dimitrova, M.; Havlicek, J.; Mitošinková, K.; Stöckel, J.; Varju, J.; Popov, Tsv K.; Komm, M.; Dejarnac, R.; Hacek, P.; Panek, R.; the COMPASS Team
2018-02-01
This paper presents the results from swept probe measurements in the divertor region of the COMPASS tokamak in D-shaped, L-mode discharges, with toroidal magnetic field BT = 1.15 T, plasma current Ip = 180 kA and line-average electron densities varying from 2 to 8×1019 m-3. Using neutral beam injection heating, the electron energy distribution function is studied before and during the application of the beam. The current-voltage characteristics data are processed using the first-derivative probe technique. This technique allows one to evaluate the plasma potential and the real electron energy distribution function (respectively, the electron temperatures and densities). At the low average electron density of 2×1019 m-3, the electron energy distribution function is bi-Maxwellian with a low-energy electron population with temperatures 4-6 eV and a high-energy electron group 12-25 eV. As the line-average electron density is increased, the electron temperatures decrease. At line-average electron densities above 7×1019 m-3, the electron energy distribution function is found to be Maxwellian with a temperature of 6-8.5 eV. The effect of the neutral beam injection heating power in the divertor region is also studied.
International Nuclear Information System (INIS)
Denysenko, I. B.; Azarenkov, N. A.; Kersten, H.
2016-01-01
Analytical expressions describing the variation of electron energy distribution function (EEDF) in an afterglow of a plasma are obtained. Especially, the case when the electron energy loss is mainly due to momentum-transfer electron-neutral collisions is considered. The study is carried out for different EEDFs in the steady state, including Maxwellian and Druyvesteyn distributions. The analytical results are not only obtained for the case when the rate for momentum-transfer electron-neutral collisions is independent on electron energy but also for the case when the collisions are a power function of electron energy. Using analytical expressions for the EEDF, the effective electron temperature and charge of the dust particles, which are assumed to be present in plasma, are calculated for different afterglow durations. An analytical expression for the rate describing collection of electrons by dust particles for the case when the rate for momentum-transfer electron-neutral collisions is independent on electron energy is also derived. The EEDF profile and, as a result, the effective electron temperature and dust charge are sufficiently different in the cases when the rate for momentum-transfer electron-neutral collisions is independent on electron energy and when the rate is a power function of electron energy.
Awad, E M
1999-01-01
In this work, we have studied the effect of the radiation damage caused by the incident particles on the activation energy of etching for CR-39 samples. The damage produced by the incident particle is expressed in terms of the linear energy transfer (LET). CR-39 samples from American Acrylic were irradiated to three different LET particles. These are N (LET sub 2 sub 0 sub 0 = 20 KeV/mu m) as a light particle, Fe (LET sub 2 sub 0 sub 0 = 110 KeV/mu m) as a medium particle and fission fragments (ff) from a sup 2 sup 5 sup 2 Cf source as heavy particles. In general the bulk etch rate was calculated using the weight difference method and the track etch rate was determined using the track geometry at various temperatures (50-90 deg. C) and concentrations (4-9 N) of the NaOH etchant. The average activation energy E sub b related to the bulk etch rate v sub b was calculated from 1n v sub b vs. 1/T. The average activation energy E sub t related to the track etch rate v sub t was estimated from 1n v sub t vs. 1/T. It...
Nuclear Statistical Equilibrium for compact stars: modelling the nuclear energy functional
International Nuclear Information System (INIS)
Aymard, Francois
2015-01-01
and beyond. At densities above two-three times saturation, other degrees of freedom are expected to appear, which potentially lead to other consistency problems but this issue will not be treated in this thesis. The thesis is divided into three parts. In part I, we present the Nuclear Statistical Equilibrium model based on the grand canonical statistics and non-relativistic Skyrme interactions. Results at β-equilibrium are shown and the importance of the clusters distribution as well as a realistic treatment for the free energy model is discussed. Part II investigates the functional behavior of the baryonic energy in the Wigner-Seitz cell within the Extended-Thomas-Fermi approximation. In particular, both bulk and surface in-medium effects are studied, and their dependence on cluster size and asymmetry as well as gas densities and asymmetry is investigated. A preliminary result of in-medium surface effects is presented within some approximations in the case of β-equilibrated matter. In part III, we develop approximations in order to obtain a reliable analytical expression of the mass formula, directly linked to the functional form and parameters of the Skyrme interaction. In this part, we mainly focus on nuclei in vacuum, and analyse the different binding energy components in terms of bulk and surface properties, as well as isovector and isoscalar properties. (author)
Mouchtouris, S.; Kokkoris, G.
2018-01-01
A generalized equation for the electron energy probability function (EEPF) of inductively coupled Ar plasmas is proposed under conditions of nonlocal electron kinetics and diffusive cooling. The proposed equation describes the local EEPF in a discharge and the independent variable is the kinetic energy of electrons. The EEPF consists of a bulk and a depleted tail part and incorporates the effect of the plasma potential, Vp, and pressure. Due to diffusive cooling, the break point of the EEPF is eVp. The pressure alters the shape of the bulk and the slope of the tail part. The parameters of the proposed EEPF are extracted by fitting to measure EEPFs (at one point in the reactor) at different pressures. By coupling the proposed EEPF with a hybrid plasma model, measurements in the gaseous electronics conference reference reactor concerning (a) the electron density and temperature and the plasma potential, either spatially resolved or at different pressure (10-50 mTorr) and power, and (b) the ion current density of the electrode, are well reproduced. The effect of the choice of the EEPF on the results is investigated by a comparison to an EEPF coming from the Boltzmann equation (local electron kinetics approach) and to a Maxwellian EEPF. The accuracy of the results and the fact that the proposed EEPF is predefined renders its use a reliable alternative with a low computational cost compared to stochastic electron kinetic models at low pressure conditions, which can be extended to other gases and/or different electron heating mechanisms.
Baryon scattering at high energies. Wave function, impact factor, and gluon radiation
International Nuclear Information System (INIS)
Bartels, J.; Motyka, L.; Jagellonian Univ., Krakow
2007-11-01
The scattering of a baryon consisting of three massive quarks is investigated in the high energy limit of perturbative QCD. A model of a relativistic proton-like wave function, dependent on valence quark longitudinal and transverse momenta and on quark helicities, is proposed, and we derive the baryon impact factors for two, three and four t-channel gluons. We find that the baryonic impact factor can be written as a sum of three pieces: in the first one a subsystem consisting of two of the three quarks behaves very much like the quark-antiquark pair in γ * scattering, whereas the third quark acts as a spectator. The second term belongs to the odderon, whereas in the third (C-even) piece all three quarks participate in the scattering. This term is new and has no analogue in γ * scattering. We also study the small x evolution of gluon radiation for each of these three terms. The first term follows the same pattern of gluon radiation as the γ * -initiated quark-antiquark dipole, and, in particular, it contains the BFKL evolution followed by the 2→4 transition vertex (triple Pomeron vertex). The odderon-term is described by the standard BKP evolution, and the baryon couples to both known odderon solutions, the Janik-Wosiek solution and the BLV solution. Finally, the t-channel evolution of the third term starts with a three reggeized gluon state which then, via a new 3→4 transition vertex, couples to the four gluon (two-Pomeron) state. We briefly discuss a few consequences of these findings, in particular the pattern of unitarization of high energy baryon scattering amplitudes. (orig.)
Baryon scattering at high energies. Wave function, impact factor, and gluon radiation
Energy Technology Data Exchange (ETDEWEB)
Bartels, J. [Hamburg Univ. (Germany). 2. Inst. fuer Theoretische Physik; Motyka, L. [Hamburg Univ. (Germany). 2. Inst. fuer Theoretische Physik]|[Jagellonian Univ., Krakow (Poland). Inst. of Physics
2007-11-15
The scattering of a baryon consisting of three massive quarks is investigated in the high energy limit of perturbative QCD. A model of a relativistic proton-like wave function, dependent on valence quark longitudinal and transverse momenta and on quark helicities, is proposed, and we derive the baryon impact factors for two, three and four t-channel gluons. We find that the baryonic impact factor can be written as a sum of three pieces: in the first one a subsystem consisting of two of the three quarks behaves very much like the quark-antiquark pair in {gamma}{sup *} scattering, whereas the third quark acts as a spectator. The second term belongs to the odderon, whereas in the third (C-even) piece all three quarks participate in the scattering. This term is new and has no analogue in {gamma}{sup *} scattering. We also study the small x evolution of gluon radiation for each of these three terms. The first term follows the same pattern of gluon radiation as the {gamma}{sup *}-initiated quark-antiquark dipole, and, in particular, it contains the BFKL evolution followed by the 2{yields}4 transition vertex (triple Pomeron vertex). The odderon-term is described by the standard BKP evolution, and the baryon couples to both known odderon solutions, the Janik-Wosiek solution and the BLV solution. Finally, the t-channel evolution of the third term starts with a three reggeized gluon state which then, via a new 3{yields}4 transition vertex, couples to the four gluon (two-Pomeron) state. We briefly discuss a few consequences of these findings, in particular the pattern of unitarization of high energy baryon scattering amplitudes. (orig.)
Robertson, William C
2002-01-01
Confounded by kinetic energy? Suspect that teaching about simple machines isn t really so simple? Exasperated by electricity? If you fear the study of energy is beyond you, this entertaining book will do more than introduce you to the topic. It will help you actually understand it. At the book s heart are easy-to-grasp explanations of energy basics work, kinetic energy, potential energy, and the transformation of energy and energy as it relates to simple machines, heat energy, temperature, and heat transfer. Irreverent author Bill Robertson suggests activities that bring the basic concepts of energy to life with common household objects. Each chapter ends with a summary and an applications section that uses practical examples such as roller coasters and home heating systems to explain energy transformations and convection cells. The final chapter brings together key concepts in an easy-to-grasp explanation of how electricity is generated. Energy is the second book in the Stop Faking It! series published by NS...
The potential adverse effect of energy drinks on executive functions in early adolescence
Directory of Open Access Journals (Sweden)
Tamara Van Batenburg-Eddes
2014-05-01
Full Text Available Introduction. Manufacturers of energy drinks (EDs claim their products improve cognitive performance. Young adolescents are in a critical developmental phase. The impact of ED intake on their development is not yet clear. Therefore, we studied the associations of both caffeine intake and ED consumption with executive functions (EFs, and the role of pubertal status and sleeping problems. Methods. A sample of 509 participants (mean age: 13.1 years, SD 0.85 participated in the study. The level of pubertal development was classified in five pubertal status categories. Participants were asked to report their caffeine (for example coffee and ED consumption for each day of the week. In addition, they indicated sleep quality by reporting problems falling asleep or waking up and/or interrupted sleep. EFs were assessed by self- and parent reports of the Behavior Rating Inventory of Executive Function (BRIEF. Results. Consuming on average one or more ED(s a day was associated with more problems in self-reported behavior regulation and metacognition, and with more problems in parent-reported metacognition. Only high caffeine consumption (two or more cups a day was associated with parent-reported problems with metacognition. The sum of caffeine and ED use was associated with a higher amount of problems with self-reported metacognition and parent reported behavior regulation. The effect estimates for the association between caffeine and ED use combined and EFs did not exceed those of EDs or caffeine separately. Adjusting for pubertal status, gender, educational level, number of sleeping problems and hours of sleep did not change the effect estimates substantially. Conclusion. The observed associations between ED consumption and EFs suggest that regular consumption of EDs - even in moderate amounts – may have a negative impact on daily life behaviors related to EF in young adolescents.
Sergiievskyi, Volodymyr P; Jeanmairet, Guillaume; Levesque, Maximilien; Borgis, Daniel
2014-06-05
Molecular density functional theory (MDFT) offers an efficient implicit-solvent method to estimate molecule solvation free-energies, whereas conserving a fully molecular representation of the solvent. Even within a second-order approximation for the free-energy functional, the so-called homogeneous reference fluid approximation, we show that the hydration free-energies computed for a data set of 500 organic compounds are of similar quality as those obtained from molecular dynamics free-energy perturbation simulations, with a computer cost reduced by 2-3 orders of magnitude. This requires to introduce the proper partial volume correction to transform the results from the grand canonical to the isobaric-isotherm ensemble that is pertinent to experiments. We show that this correction can be extended to 3D-RISM calculations, giving a sound theoretical justification to empirical partial molar volume corrections that have been proposed recently.
Seino, Junji; Kageyama, Ryo; Fujinami, Mikito; Ikabata, Yasuhiro; Nakai, Hiromi
2018-06-01
A semi-local kinetic energy density functional (KEDF) was constructed based on machine learning (ML). The present scheme adopts electron densities and their gradients up to third-order as the explanatory variables for ML and the Kohn-Sham (KS) kinetic energy density as the response variable in atoms and molecules. Numerical assessments of the present scheme were performed in atomic and molecular systems, including first- and second-period elements. The results of 37 conventional KEDFs with explicit formulae were also compared with those of the ML KEDF with an implicit formula. The inclusion of the higher order gradients reduces the deviation of the total kinetic energies from the KS calculations in a stepwise manner. Furthermore, our scheme with the third-order gradient resulted in the closest kinetic energies to the KS calculations out of the presented functionals.
International Nuclear Information System (INIS)
Zhang, Li; YangDai, Tianyi
2016-01-01
A method for deriving the molecular interference function (MIF) of an unknown liquid for security screening is presented. Based on the effective atomic number reconstructed from dual-energy computed tomography (CT), equivalent molecular formula of the liquid is estimated. After a series of optimizations, the MIF and a new effective atomic number are finally obtained from the X-ray diffraction (XRD) profile. The proposed method generates more accurate results with less sensitivity to the noise and data deficiency of the XRD profile. - Highlights: • EDXRD combined with dual-energy CT has been utilized for deriving the molecular interference function of an unknown liquid. • The liquid's equivalent molecular formula is estimated based on the effective atomic number reconstructed from dual-energy CT. • The proposed method provides two ways to estimate the molecular interference function: the simplified way and accurate way. • A new effective atomic number of the liquid could be obtained.
Álvarez Ruiz, Antón; Reyes Moreno, María
2011-01-01
This article analyzes the web pages of the major companies in the energy market (electricity and gas) of the more developed countries (EU and North America). The present situation of the market is very significant: For the first time, the Government of these countries have given permission to liberalize the power market. This process goes on very slowly but we can see now some changes that leads to a process of concentration, through acquisitions, merges and commercial agreements between the ...
Hung, L.; Guedj, C.; Bernier, N.; Blaise, P.; Olevano, V.; Sottile, F.
2016-04-01
We present the valence electron energy-loss spectrum and the dielectric function of monoclinic hafnia (m -HfO2) obtained from time-dependent density-functional theory (TDDFT) predictions and compared to energy-filtered spectroscopic imaging measurements in a high-resolution transmission-electron microscope. Fermi's golden rule density-functional theory (DFT) calculations can capture the qualitative features of the energy-loss spectrum, but we find that TDDFT, which accounts for local-field effects, provides nearly quantitative agreement with experiment. Using the DFT density of states and TDDFT dielectric functions, we characterize the excitations that result in the m -HfO2 energy-loss spectrum. The sole plasmon occurs between 13 and 16 eV, although the peaks ˜28 and above 40 eV are also due to collective excitations. We furthermore elaborate on the first-principles techniques used, their accuracy, and remaining discrepancies among spectra. More specifically, we assess the influence of Hf semicore electrons (5 p and 4 f ) on the energy-loss spectrum, and find that the inclusion of transitions from the 4 f band damps the energy-loss intensity in the region above 13 eV. We study the impact of many-body effects in a DFT framework using the adiabatic local-density approximation (ALDA) exchange-correlation kernel, as well as from a many-body perspective using "scissors operators" matched to an ab initio G W calculation to account for self-energy corrections. These results demonstrate some cancellation of errors between self-energy and excitonic effects, even for excitations from the Hf 4 f shell. We also simulate the dispersion with increasing momentum transfer for plasmon and collective excitation peaks.
International Nuclear Information System (INIS)
Lorenzen, J.; Brune, D.
1973-01-01
The present chapter has been formulated with the aim of making it useful in various fields of nuclear applications with emphasis on charged particle activation analysis. Activation analysis of light elements using charged particles has proved to be an important tool in solving various problems in analytical chemistry, e g those associated with metal surfaces. Scientists desiring to evaluate the distribution of light elements in the surface of various matrices using charged particle reactions require accurate data on cross sections in the MeV-region. A knowledge of cross section data and yield-functions is of great interest in many applied fields involving work with charged particles, such as radiological protection and health physics, material research, semiconductor material investigations and corrosion chemistry. The authors therefore decided to collect a limited number of data which find use in these fields. Although the compilation is far from being complete, it is expected to be of assistance in devising measurements of charged particle reactions in Van de Graaff or other low energy accelerators
Directory of Open Access Journals (Sweden)
Markus Börgardts
2017-04-01
Full Text Available The covalent attachment of organic fluorophores in mesoporous silica matrices for usage as energy down converting phosphors without employing inorganic transition or rare earth metals is reported in this article. Triethoxysilylpropyl-substituted derivatives of the blue emitting perylene, green emitting benzofurazane, and red emitting Nile red were synthesized and applied in the synthesis of mesoporous hybrid materials by postsynthetic grafting to commercially available MCM-41. These individually dye-functionalized hybrid materials are mixed in variable ratios to furnish a powder capable of emitting white light with CIE chromaticity coordinates of x = 0.33, y = 0.33 and an external quantum yield of 4.6% upon irradiation at 410 nm. Furthermore, as a proof of concept two different device setups of commercially available UV light emitting diodes, are coated with silica monoliths containing the three triethoxysilylpropyl-substituted fluorophore derivatives. These coatings are able to convert the emitted UV light into light with correlated color temperatures of very cold white (41100 K, 10700 K as well as a greenish white emission with correlated color temperatures of about 5500 K.
Non-thermal plasma instabilities induced by deformation of the electron energy distribution function
Dyatko, N. A.; Kochetov, I. V.; Napartovich, A. P.
2014-08-01
Non-thermal plasma is a key component in gas lasers, microelectronics, medical applications, waste gas cleaners, ozone generators, plasma igniters, flame holders, flow control in high-speed aerodynamics and others. A specific feature of non-thermal plasma is its high sensitivity to variations in governing parameters (gas composition, pressure, pulse duration, E/N parameter). This sensitivity is due to complex deformations of the electron energy distribution function (EEDF) shape induced by variations in electric field strength, electron and ion number densities and gas excitation degree. Particular attention in this article is paid to mechanisms of instabilities based on non-linearity of plasma properties for specific conditions: gas composition, steady-state and decaying plasma produced by the electron beam, or by an electric current pulse. The following effects are analyzed: the negative differential electron conductivity; the absolute negative electron mobility; the stepwise changes of plasma properties induced by the EEDF bi-stability; thermo-current instability and the constriction of the glow discharge column in rare gases. Some of these effects were observed experimentally and some of them were theoretically predicted and still wait for experimental confirmation.
Energy Technology Data Exchange (ETDEWEB)
Lorenzen, J; Brune, D
1973-07-01
The present chapter has been formulated with the aim of making it useful in various fields of nuclear applications with emphasis on charged particle activation analysis. Activation analysis of light elements using charged particles has proved to be an important tool in solving various problems in analytical chemistry, e g those associated with metal surfaces. Scientists desiring to evaluate the distribution of light elements in the surface of various matrices using charged particle reactions require accurate data on cross sections in the MeV-region. A knowledge of cross section data and yield-functions is of great interest in many applied fields involving work with charged particles, such as radiological protection and health physics, material research, semiconductor material investigations and corrosion chemistry. The authors therefore decided to collect a limited number of data which find use in these fields. Although the compilation is far from being complete, it is expected to be of assistance in devising measurements of charged particle reactions in Van de Graaff or other low energy accelerators
Alaverdashvili, Mariam; Hackett, Mark J; Caine, Sally; Paterson, Phyllis G
2017-04-01
While protein-energy malnutrition in the adult has been reported to induce motor abnormalities and exaggerate motor deficits caused by stroke, it is not known if alterations in mature cortical neurons contribute to the functional deficits. Therefore, we explored if PEM in adult rats provoked changes in the biochemical profile of neurons in the forelimb and hindlimb regions of the motor cortex. Fourier transform infrared spectroscopic imaging using a synchrotron generated light source revealed for the first time altered lipid composition in neurons and subcellular domains (cytosol and nuclei) in a cortical layer and region-specific manner. This change measured by the area under the curve of the δ(CH 2 ) band may indicate modifications in membrane fluidity. These PEM-induced biochemical changes were associated with the development of abnormalities in forelimb use and posture. The findings of this study provide a mechanism by which PEM, if not treated, could exacerbate the course of various neurological disorders and diminish treatment efficacy. Copyright © 2017 Elsevier Inc. All rights reserved.
International Nuclear Information System (INIS)
Yanguas-Gil, A.; Cotrino, J.; Gonzalez-Elipe, A.R.
2005-01-01
In this work the influence of the excited states on the electron-energy distribution function has been determined for an argon microwave discharge at low pressure. A collisional-radiative model of argon has been developed taking into account the most recent experimental and theoretical values of argon-electron-impact excitation cross sections. The model has been solved along with the electron Boltzmann equation in order to study the influence of the inelastic collisions from the argon excited states on the electron-energy distribution function. Results show that under certain conditions the excited states can play an important role in determining the shape of the distribution function and the mean kinetic energy of the electrons, deplecting the high-energy tail due to inelastic processes from the excited states, especially from the 4s excited configuration. It has been found that from the populations of the excited states an excitation temperature can be defined. This excitation temperature, which can be experimentally determined by optical emission spectroscopy, is lower than the electron kinetic temperature obtained from the electron-energy distribution function
Zhang, Xi; Huang, Xuezhen; Li, Chensha; Jiang, Hongrui
2013-08-14
Dye-sensitized solar cells with an energy storage function are demonstrated by modifying its counter electrode with a poly (vinylidene fluoride)/ZnO nanowire array composite. This simplex device could still function as an ordinary solar cell with a steady photocurrent output even after being fully charged. An energy storage density of 2.14 C g(-1) is achieved, while simultaneously a 3.70% photo-to-electric conversion efficiency is maintained. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
van Dronkelaar, C.; Costola, D.; Mangkuto, R.A.; Hensen, J.L.M.
2014-01-01
Underground buildings are pointed out as alternatives to conventional aboveground buildings for reducing total energy requirements, while alleviating land use and location problems. This paper investigates the potential in reducing the heating and cooling energy demand of underground buildings
The morphology of collision cascades as a function of recoil energy
International Nuclear Information System (INIS)
Heinisch, H.L.; Singh, B.N.
1989-09-01
An analytical method based on defect densities has been devised to determine the threshold energies for subcascade formation in computer simulated collision cascades. Cascades generated with the binary collision code MARLOWE in Al, Cu, Ag, Au, Fe, Mo and W were analyzed to determine the threshold energy for subcascade formation, the number of subcascades per recoil per unit energy and the average spacing of subcascades. Compared on the basis of reduced damage energy, metals of the same crystal structure have subcascade thresholds at the same reduced energy. The number of subcascades per unit reduced damage energy is about the same for metals of the same crystal structure, and the average spacing of subcascades is about the same in units of lattice parameters. Comparisons between subcascade threshold energies and average recoil energies in fission and fusion neutron environments show the spectral sensitivity of the formation of subcascades
Study of real space wave functions with electron energy loss spectrometry
Energy Technology Data Exchange (ETDEWEB)
Löffler, S.
2013-07-01
In this work, new methods to study the real space wave functions of electrons in a solid using transmission electron microscopy (TEM) and electron energy loss spectrometry (EELS) are presented. To this end, the theory of both elastic and inelastic electron scattering is treated in a density-matrix formalism. In the process, the central quantities of inelastic electron scattering - the mixed dynamic form factor (MDFF) and the double differential scattering cross section (DDSCS) - are introduced. In addition to the formal theory, several approximations and simplifications, as well as their respective validities, are discussed. Furthermore, a method for diagonalizing the mixed dynamic form factor is described, which allows calculating high resolution energy filtered TEM images with unprecedented accuracy. Subsequently, several applications of the aforementioned theory to real-world examples are presented. On the one hand, the example of Silicon serves to demonstrate how the radial wave functions in the bulk can be measured; the agreement with the theoretical predictions proves to be very good. On the other hand, the determination of the wave functions' azimuthal dependence is derived. It turns out that the symmetry of the system under investigation is crucial to the success of this endeavor. With the new techniques presented here, it will be possible to measure electronic properties with atomic resolution, which can be of great importance, particularly in material science. (author) [German] In der vorliegenden Arbeit werden neue Methoden vorgestellt, mit deren Hilfe Elektronenwellenfunktionen in Festkörpern mittels Transmissionselektronenmikroskopie (TEM) und Elektronenenergieverlustspektrometrie (EELS) direkt im Realraum vermessen werden können. Zu diesem Zweck wird sowohl die Theorie der elastischen Elektronenbeugung als auch die der inelastischen Elektronenstreuung im Dichtematrixformalismus dargestellt. Dabei werden die zentralen Größen der inelastischen
International Nuclear Information System (INIS)
1975-10-01
On the occasion of the World Environment Day the Norwegian Ministry for the Environment held a conference on growth problems in energy consumption. The themes which were treated were energy conservation, hydroelectric power, the role of nuclear power, radioactive waste disposal, fossil fuel resources, ecological limits, pollution and international aspects. Nuclear energy forms the main theme of one lecture and an aspect of several others. (JIW)
Torriti, Jacopo
2016-01-01
The impact of energy policy measures has been assessed with various appraisal and evaluation tools since the 1960s. Decision analysis, environmental impact assessment and strategic environmental assessment are all notable examples of progenitors of Regulatory Impact Assessment (RIA) in the assessment of energy policies, programmes and projects. This chapter provides overview of policy tools which have been historically applied to assess the impacts of energy policies, programmes and projects....
International Nuclear Information System (INIS)
Vancura, J.; Kostroun, V.O.
1992-01-01
The absolute total and one and two electron transfer cross sections for Ar 8+ on Ar were measured as a function of projectile laboratory energy from 0.090 to 0.550 keV/amu. The effective one electron transfer cross section dominates above 0.32 keV/amu, while below this energy, the effective two electron transfer starts to become appreciable. The total cross section varies by a factor over the energy range explored. The overall error in the cross section measurement is estimated to be ± 15%
International Nuclear Information System (INIS)
Shi, San-Qiang; Xiao, Zhihua
2015-01-01
A temperature dependent, quantitative free energy functional was developed for the modeling of hydride precipitation in zirconium alloys within a phase field scheme. The model takes into account crystallographic variants of hydrides, interfacial energy between hydride and matrix, interfacial energy between hydrides, elastoplastic hydride precipitation and interaction with externally applied stress. The model is fully quantitative in real time and real length scale, and simulation results were compared with limited experimental data available in the literature with a reasonable agreement. The work calls for experimental and/or theoretical investigations of some of the key material properties that are not yet available in the literature
Energy Technology Data Exchange (ETDEWEB)
Mi, Bin-Zhou, E-mail: mbzfjerry2008@126.com [Department of Basic Curriculum, North China Institute of Science and Technology, Beijing 101601 (China); Department of Physics, School of Mathematics and Physics, University of Science and Technology Beijing, Beijing 100083 (China); Zhai, Liang-Jun [The School of Mathematics and Physics, Jiangsu University of Technology, Changzhou 213001 (China); Hua, Ling-Ling [Department of Basic Curriculum, North China Institute of Science and Technology, Beijing 101601 (China)
2016-01-15
The effect of magnetic spin correlation on the thermodynamic properties of Heisenberg ferromagnetic single-walled nanotubes are comprehensively investigated by use of the double-time Green's function method. The influence of temperature, spin quantum number, diameter of the tube, anisotropy strength and external magnetic field to internal energy, free energy, and magnon specific heat are carefully calculated. Compared to the mean field approximation, the consideration of the magnetic correlation effect significantly improves the internal energy values at finite temperature, while it does not so near zero temperature, and this effect is related to the diameter of the tube, anisotropy strength, and spin quantum number. The magnetic correlation effect lowers the internal energy at finite temperature. As a natural consequence of the reduction of the internal energy, the specific heat is reduced, and the free energy is elevated. - Highlights: • Magnon specific heat and free energy of Heisenberg ferromagnetic single-walled nanotubes (HFM-SWNTs) are investigated. • The magnetic correlations effect has a considerable contribution to the thermodynamics properties of HFM-SWNTs. • Magnetic correlation effects are always to lower the internal energy at finite temperature. • At Curie point, magnetic correlation energy is much less than zero. • The peak values of magnon specific heat curves rise and shift right towards higher temperatures with the diameter of tubes, the anisotropy strength, and the spin quantum number rising.
International Nuclear Information System (INIS)
2003-01-01
In the framework of the National Debate on the energies in a context of a sustainable development some associations for the environment organized a debate on the nuclear interest facing the renewable energies. The first part presents the nuclear energy as a possible solution to fight against the greenhouse effect and the associated problem of the wastes management. The second part gives information on the solar energy and the possibilities of heat and electric power production. A presentation of the FEE (French wind power association) on the situation and the development of the wind power in France, is also provided. (A.L.B.)
Running coupling corrections to high energy inclusive gluon production
International Nuclear Information System (INIS)
Horowitz, W.A.; Kovchegov, Yuri V.
2011-01-01
We calculate running coupling corrections for the lowest-order gluon production cross section in high energy hadronic and nuclear scattering using the BLM scale-setting prescription. In the final answer for the cross section the three powers of fixed coupling are replaced by seven factors of running coupling, five in the numerator and two in the denominator, forming a 'septumvirate' of running couplings, analogous to the 'triumvirate' of running couplings found earlier for the small-x BFKL/BK/JIMWLK evolution equations. It is interesting to note that the two running couplings in the denominator of the 'septumvirate' run with complex-valued momentum scales, which are complex conjugates of each other, such that the production cross section is indeed real. We use our lowest-order result to conjecture how running coupling corrections may enter the full fixed-coupling k T -factorization formula for gluon production which includes nonlinear small-x evolution.
Diquark fragmentation functions in hadron-nucleon interactions at 19 GeV/c and other energies
International Nuclear Information System (INIS)
Bakken, V.; Breivik, F.O.; Jacobsen, T.
New data on pion production in pn-interactions at 19 GeV/c are used, together with earlier data on pion production in pn (π + n) at other energies, to determine the diquark fragmentation functions Dsup(π) +- sub(dd)(=Dsup(π) +- sub(uu)) and Dsup(π)sub(ud) in the neutron and proton fragmentation regions. Typical high energy data on pion production in pp-interactions are also considered. The unfavoured fragmentation function Dsup(π) + sub(dd)(x) is found to be much smaller than the favoured fragmentati ion function Dsup(π) - sub(dd)(x) and to have a steeper x-dependence. The diquark fragmentation functions agree very well with those from v(v - )- proton interactions as expected from quark parton models
Bergeest, Jan-Philip; Rohr, Karl
2012-10-01
In high-throughput applications, accurate and efficient segmentation of cells in fluorescence microscopy images is of central importance for the quantification of protein expression and the understanding of cell function. We propose an approach for segmenting cell nuclei which is based on active contours using level sets and convex energy functionals. Compared to previous work, our approach determines the global solution. Thus, the approach does not suffer from local minima and the segmentation result does not depend on the initialization. We consider three different well-known energy functionals for active contour-based segmentation and introduce convex formulations of these functionals. We also suggest a numeric approach for efficiently computing the solution. The performance of our approach has been evaluated using fluorescence microscopy images from different experiments comprising different cell types. We have also performed a quantitative comparison with previous segmentation approaches. Copyright © 2012 Elsevier B.V. All rights reserved.
International Nuclear Information System (INIS)
Hemanadhan, M; Shamim, Md; Harbola, Manoj K
2014-01-01
The modified local spin density (MLSD) functional and the related local potential for excited states is tested by employing the ionization potential theorem. The exchange functional for an excited state is constructed by splitting k-space. Since its functional derivative cannot be obtained easily, the corresponding exchange potential is given by an analogy to its ground-state counterpart. Further, to calculate the highest occupied orbital energy ϵ max accurately, the potential is corrected for its asymptotic behaviour by employing the van Leeuwen and Baerends (LB) correction to it. ϵ max so obtained is then compared with the ΔSCF ionization energy calculated using the MLSD functional with self-interaction correction for the orbitals involved in the transition. It is shown that the two match quite accurately. The match becomes even better by tuning the LB correction with respect to a parameter in it. (paper)
Haghighi Mood, Kaveh; Lüchow, Arne
2017-08-17
Diffusion quantum Monte Carlo calculations with partial and full optimization of the guide function are carried out for the dissociation of the FeS molecule. For the first time, quantum Monte Carlo orbital optimization for transition metal compounds is performed. It is demonstrated that energy optimization of the orbitals of a complete active space wave function in the presence of a Jastrow correlation function is required to obtain agreement with the experimental dissociation energy. Furthermore, it is shown that orbital optimization leads to a 5 Δ ground state, in agreement with experiments but in disagreement with other high-level ab initio wave function calculations which all predict a 5 Σ + ground state. The role of the Jastrow factor in DMC calculations with pseudopotentials is investigated. The results suggest that a large Jastrow factor may improve the DMC accuracy substantially at small additional cost.
Determination of the S-wave scattering shape parameter P from the zero-energy wave function
International Nuclear Information System (INIS)
Kermode, M.W.; van Dijk, W.
1990-01-01
We show that for S-wave scattering at an energy k 2 by a local potential which supports no more than one bound state, the shape parameter P and coefficients of higher powers of k 2 in the effective range expansion function cotδ=-1/a+1/2 r 0 k 2 -Pr 0 3 k 3 +Qr 0 5 k 6 +..., where δ is the phase shift, may be obtained from the zero-energy wave function, u 0 (r). Thus δ itself may be determined from u 0 . We show that Pr 0 3 =∫ 0 R [β(r)u 0 2 (r)-bar β(r)bar u 0 2 (r)]dr, where r 0 is the effective range, β(r) is determined from an integral involving the wave function, and bar β(r) is a simple function of r which involves the scattering length and effective range
Energy Technology Data Exchange (ETDEWEB)
Deogracias, E.C.; Wood, J.L.; Wagner, E.C.; Kearfott, K.J
1999-02-11
The CEPXS/ONEDANT code package was used to produce a library of depth-dose profiles for monoenergetic electrons in various materials for energies ranging from 500 keV to 5 MeV in 10 keV increments. The various materials for which depth-dose functions were derived include: lithium fluoride (LiF), aluminium oxide (Al{sub 2}O{sub 3}), beryllium oxide (BeO), calcium sulfate (CaSO{sub 4}), calcium fluoride (CaF{sub 2}), lithium boron oxide (LiBO), soft tissue, lens of the eye, adiopose, muscle, skin, glass and water. All materials data sets were fit to five polynomials, each covering a different range of electron energies, using a least squares method. The resultant three dimensional, fifth-order polynomials give the dose as a function of depth and energy for the monoenergetic electrons in each material. The polynomials can be used to describe an energy spectrum by summing the doses at a given depth for each energy, weighted by the spectral intensity for that energy. An application of the polynomial is demonstrated by explaining the energy dependence of thermoluminescent detectors (TLDs) and illustrating the relationship between TLD signal and actual shallow dose due to beta particles.
Panel, Nicolas; Sun, Young Joo; Fuentes, Ernesto J; Simonson, Thomas
2017-01-01
PDZ domains generally bind short amino acid sequences at the C-terminus of target proteins, and short peptides can be used as inhibitors or model ligands. Here, we used experimental binding assays and molecular dynamics simulations to characterize 51 complexes involving the Tiam1 PDZ domain and to test the performance of a semi-empirical free energy function. The free energy function combined a Poisson-Boltzmann (PB) continuum electrostatic term, a van der Waals interaction energy, and a surface area term. Each term was empirically weighted, giving a Linear Interaction Energy or "PB/LIE" free energy. The model yielded a mean unsigned deviation of 0.43 kcal/mol and a Pearson correlation of 0.64 between experimental and computed free energies, which was superior to a Null model that assumes all complexes have the same affinity. Analyses of the models support several experimental observations that indicate the orientation of the α 2 helix is a critical determinant for peptide specificity. The models were also used to predict binding free energies for nine new variants, corresponding to point mutants of the Syndecan1 and Caspr4 peptides. The predictions did not reveal improved binding; however, they suggest that an unnatural amino acid could be used to increase protease resistance and peptide lifetimes in vivo . The overall performance of the model should allow its use in the design of new PDZ ligands in the future.
Directory of Open Access Journals (Sweden)
Nicolas Panel
2017-09-01
Full Text Available PDZ domains generally bind short amino acid sequences at the C-terminus of target proteins, and short peptides can be used as inhibitors or model ligands. Here, we used experimental binding assays and molecular dynamics simulations to characterize 51 complexes involving the Tiam1 PDZ domain and to test the performance of a semi-empirical free energy function. The free energy function combined a Poisson-Boltzmann (PB continuum electrostatic term, a van der Waals interaction energy, and a surface area term. Each term was empirically weighted, giving a Linear Interaction Energy or “PB/LIE” free energy. The model yielded a mean unsigned deviation of 0.43 kcal/mol and a Pearson correlation of 0.64 between experimental and computed free energies, which was superior to a Null model that assumes all complexes have the same affinity. Analyses of the models support several experimental observations that indicate the orientation of the α2 helix is a critical determinant for peptide specificity. The models were also used to predict binding free energies for nine new variants, corresponding to point mutants of the Syndecan1 and Caspr4 peptides. The predictions did not reveal improved binding; however, they suggest that an unnatural amino acid could be used to increase protease resistance and peptide lifetimes in vivo. The overall performance of the model should allow its use in the design of new PDZ ligands in the future.
On the twist-2 contributions to polarized structure functions and new sum rules
International Nuclear Information System (INIS)
Bluemlein, J.; Kochelev, N.
1996-03-01
The twist-2 contributions to the polarized structure functions in deep inelastic lepton-hadron scattering are calculated including the exchange of weak bosons and using both the operator product expansion and the covariant parton model. A new relation between two structure functions leading to a sequence of new sum rules is found. The light quark mass corrections to the structure functions are derived in lowest order QCD. (orig.)
Drukarev, Evgeny G
2016-01-01
This self-contained text introduces readers to the field of high-energy atomic physics - a new regime of photon-atom interactions in which the photon energies significantly exceed the atomic or molecular binding energies, and which opened up with the recent advent of new synchrotron sources. From a theoretical point of view, a small-parameter characteristic of the bound system emerged, making it possible to perform analytic perturbative calculations that can in turn serve as benchmarks for more powerful numerical computations. The first part of the book introduces readers to the foundations of this new regime and its theoretical treatment. In particular, the validity of the small-parameter perturbation expansion and of the lowest-order approximation is critically reviewed. The following chapters then apply these insights to various atomic processes, such as photoionization as a many-body problem, dominant mechanisms for the production of ions at higher energies, Compton scattering and ionization accompanied b...
International Nuclear Information System (INIS)
Salameh, Chrystelle
2014-01-01
Porous inorganic materials are of great interest owing to their potential in energy applications. The general objective of the present thesis concerns the development of functional (carbon)nitrides for hydrogen generation and storage (material design, elaboration, properties and applications). The PDCs route, which offers a large number of opportunities in chemistry and ceramic sciences, has been applied to produce functional (carbon)nitrides materials. Firstly, we prepared porous binary systems such as AlN and BN by replicating the structure of CMK-3 and that of activated carbon. After pyrolysis and removal of the template, we demonstrated the feasibility of producing nitrides with tailored porosity. Moreover, by coupling the PDCs route with the aerogel technology, we succeeded in preparing polymer-derived AlN and BN aerogels. We assessed the potential of these porous AlN and BN materials in nano-confinement of two chemical hydrides, namely sodium alanate and ammonia borane, respectively. In both cases, the nano-confinement destabilized the network of the hydride and favored the release of H 2 at low temperature. Besides, in the case of nano-confined ammonia borane, no evolution of undesired gaseous by-products was observed, which means that pure hydrogen was produced in our conditions. Secondly, we prepared porous quaternary systems through the association of AlN/BN with Si-based ceramics. In particular, we investigated the preparation of SiAlCN with tailored porosity by using two approaches: the 'molecular building block' and 'single-source precursor' approaches. Concerning the former, we investigated the preparation of ordered meso-porous materials to be used as catalytic supports for hydrolysis of alkaline solution of sodium borohydride. We succeeded in generating high amounts of H 2 with attractive kinetics. Concerning the latter approach, the work was focused on the investigation of the chemistry of SiAlCN and SiBCN materials with a
Exchange splitting of the interaction energy and the multipole expansion of the wave function
Energy Technology Data Exchange (ETDEWEB)
Gniewek, Piotr, E-mail: pgniewek@tiger.chem.uw.edu.pl; Jeziorski, Bogumił, E-mail: jeziorsk@chem.uw.edu.pl [Faculty of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw (Poland)
2015-10-21
The exchange splitting J of the interaction energy of the hydrogen atom with a proton is calculated using the conventional surface-integral formula J{sub surf}[Φ], the volume-integral formula of the symmetry-adapted perturbation theory J{sub SAPT}[Φ], and a variational volume-integral formula J{sub var}[Φ]. The calculations are based on the multipole expansion of the wave function Φ, which is divergent for any internuclear distance R. Nevertheless, the resulting approximations to the leading coefficient j{sub 0} in the large-R asymptotic series J(R) = 2e{sup −R−1}R(j{sub 0} + j{sub 1}R{sup −1} + j{sub 2}R{sup −2} + ⋯) converge with the rate corresponding to the convergence radii equal to 4, 2, and 1 when the J{sub var}[Φ], J{sub surf}[Φ], and J{sub SAPT}[Φ] formulas are used, respectively. Additionally, we observe that also the higher j{sub k} coefficients are predicted correctly when the multipole expansion is used in the J{sub var}[Φ] and J{sub surf}[Φ] formulas. The symmetry adapted perturbation theory formula J{sub SAPT}[Φ] predicts correctly only the first two coefficients, j{sub 0} and j{sub 1}, gives a wrong value of j{sub 2}, and diverges for higher j{sub n}. Since the variational volume-integral formula can be easily generalized to many-electron systems and evaluated with standard basis-set techniques of quantum chemistry, it provides an alternative for the determination of the exchange splitting and the exchange contribution of the interaction potential in general.
International Nuclear Information System (INIS)
Horacek, Miroslav
2005-01-01
The use of a thinned back-side illuminated charge coupled device chip as two-dimensional sensor working in direct electron bombarded mode at optimum energy of the incident signal electrons is demonstrated and the measurements of the modulation transfer function (MTF) and detective quantum efficiency (DQE) are described. The MTF was measured for energy of electrons 4 keV using an edge projection method and a stripe projection method. The decrease of the MTF for a maximum spatial frequency of 20.8 cycles/mm, corresponding to the pixel size 24x24 μm, is 0.75≅-2.5 dB, and it is approximately the same for both horizontal and vertical directions. DQE was measured using an empty image and the mixing factor method. Empty images were acquired for energies of electrons from 2 to 5 keV and for various doses, ranging from nearly dark image to a nearly saturated one. DQE increases with increasing energy of bombarded electrons and reaches 0.92 for electron energy of 5 keV. For this energy the detector will be used for the angle- and energy-selective detection of signal electrons in the scanning low energy electron microscope
International Nuclear Information System (INIS)
Mirtschink, André; Gori-Giorgi, Paola; Umrigar, C. J.; Morgan, John D.
2014-01-01
Anions and radicals are important for many applications including environmental chemistry, semiconductors, and charge transfer, but are poorly described by the available approximate energy density functionals. Here we test an approximate exchange-correlation functional based on the exact strong-coupling limit of the Hohenberg-Kohn functional on the prototypical case of the He isoelectronic series with varying nuclear charge Z − and to capture in general the physics of loosely bound anions, with a tendency to strongly overbind that can be proven mathematically. We also include corrections based on the uniform electron gas which improve the results
International Nuclear Information System (INIS)
Lim, S C; Teo, L P
2007-01-01
We derive rigorously explicit formulae of the Casimir free energy at finite temperature for massless scalar field and electromagnetic field confined in a closed rectangular cavity with different boundary conditions by a zeta regularization method. We study both the low and high temperature expansions of the free energy. In each case, we write the free energy as a sum of a polynomial in temperature plus exponentially decay terms. We show that the free energy is always a decreasing function of temperature. In the cases of massless scalar field with the Dirichlet boundary condition and electromagnetic field, the zero temperature Casimir free energy might be positive. In each of these cases, there is a unique transition temperature (as a function of the side lengths of the cavity) where the Casimir energy changes from positive to negative. When the space dimension is equal to two and three, we show graphically the dependence of this transition temperature on the side lengths of the cavity. Finally we also show that we can obtain the results for a non-closed rectangular cavity by letting the size of some directions of a closed cavity go to infinity, and we find that these results agree with the usual integration prescription adopted by other authors
Optimizing virtual machine placement for energy and SLA in clouds using utility functions
Abdelkhalik Mosa; Norman W. Paton
2016-01-01
Cloud computing provides on-demand access to a shared pool of computing resources, which enables organizations to outsource their IT infrastructure. Cloud providers are building data centers to handle the continuous increase in cloud users’ demands. Consequently, these cloud data centers consume, and have the potential to waste, substantial amounts of energy. This energy consumption increases the operational cost and the CO2 emissions. The goal of this paper is to develop an optimized energy ...
Thompson, Rodger I.
2018-04-01
This investigation explores using the beta function formalism to calculate analytic solutions for the observable parameters in rolling scalar field cosmologies. The beta function in this case is the derivative of the scalar ϕ with respect to the natural log of the scale factor a, β (φ )=d φ /d ln (a). Once the beta function is specified, modulo a boundary condition, the evolution of the scalar ϕ as a function of the scale factor is completely determined. A rolling scalar field cosmology is defined by its action which can contain a range of physically motivated dark energy potentials. The beta function is chosen so that the associated "beta potential" is an accurate, but not exact, representation of the appropriate dark energy model potential. The basic concept is that the action with the beta potential is so similar to the action with the model potential that solutions using the beta action are accurate representations of solutions using the model action. The beta function provides an extra equation to calculate analytic functions of the cosmologies parameters as a function of the scale factor that are that are not calculable using only the model action. As an example this investigation uses a quintessence cosmology to demonstrate the method for power and inverse power law dark energy potentials. An interesting result of the investigation is that the Hubble parameter H is almost completely insensitive to the power of the potentials and that ΛCDM is part of the family of quintessence cosmology power law potentials with a power of zero.
International Nuclear Information System (INIS)
Gori-Giorgi, Paola; Savin, Andreas
2006-01-01
The combination of density-functional theory with other approaches to the many-electron problem through the separation of the electron-electron interaction into a short-range and a long-range contribution is a promising method, which is raising more and more interest in recent years. In this work some properties of the corresponding correlation energy functionals are derived by studying the electron-electron coalescence condition for a modified (long-range-only) interaction. A general relation for the on-top (zero electron-electron distance) pair density is derived, and its usefulness is discussed with some examples. For the special case of the uniform electron gas, a simple parametrization of the on-top pair density for a long-range only interaction is presented and supported by calculations within the ''extended Overhauser model.'' The results of this work can be used to build self-interaction corrected short-range correlation energy functionals
Nandi, Prithwish Kumar; Valsakumar, M C; Chandra, Sharat; Sahu, H K; Sundar, C S
2010-09-01
We calculate properties like equilibrium lattice parameter, bulk modulus and monovacancy formation energy for nickel (Ni), iron (Fe) and chromium (Cr) using Kohn-Sham density functional theory (DFT). We compare the relative performance of local density approximation (LDA) and generalized gradient approximation (GGA) for predicting such physical properties for these metals. We also make a relative study between two different flavors of GGA exchange correlation functional, namely PW91 and PBE. These calculations show that there is a discrepancy between DFT calculations and experimental data. In order to understand this discrepancy in the calculation of vacancy formation energy, we introduce a correction for the surface intrinsic error corresponding to an exchange correlation functional using the scheme implemented by Mattsson et al (2006 Phys. Rev. B 73 195123) and compare the effectiveness of the correction scheme for Al and the 3d transition metals.
Zhang, Xi; Jiang, Hongrui
2015-03-09
Photo-self-charging cells (PSCs) are compact devices with dual functions of photoelectric conversion and energy storage. By introducing a scattering layer in polymer-based quasi-solid-state dye-sensitized solar cells, two-electrode PSCs with highly compact structure were obtained. The charge storage function stems from the formed ion channel network in the scattering layer/polymer electrolyte system. Both the photoelectric conversion and the energy storage functions are integrated in only the photoelectrode of such PSCs. This design of PSC could continuously output power as a solar cell with considerable efficiency after being photo-charged. Such PSCs could be applied in highly-compact mini power devices.
Li, Chen; Lu, Jianfeng; Yang, Weitao
2015-12-14
We develop the gentlest ascent dynamics for Kohn-Sham density functional theory to search for the index-1 saddle points on the energy landscape of the Kohn-Sham density functionals. These stationary solutions correspond to excited states in the ground state functionals. As shown by various examples, the first excited states of many chemical systems are given by these index-1 saddle points. Our novel approach provides an alternative, more robust way to obtain these excited states, compared with the widely used ΔSCF approach. The method can be easily generalized to target higher index saddle points. Our results also reveal the physical interest and relevance of studying the Kohn-Sham energy landscape.
Zhang, DaDi; Yang, Xiaolong; Zheng, Xiao; Yang, Weitao
2018-04-01
Electron affinity (EA) is the energy released when an additional electron is attached to an atom or a molecule. EA is a fundamental thermochemical property, and it is closely pertinent to other important properties such as electronegativity and hardness. However, accurate prediction of EA is difficult with density functional theory methods. The somewhat large error of the calculated EAs originates mainly from the intrinsic delocalisation error associated with the approximate exchange-correlation functional. In this work, we employ a previously developed non-empirical global scaling correction approach, which explicitly imposes the Perdew-Parr-Levy-Balduz condition to the approximate functional, and achieve a substantially improved accuracy for the calculated EAs. In our approach, the EA is given by the scaling corrected Kohn-Sham lowest unoccupied molecular orbital energy of the neutral molecule, without the need to carry out the self-consistent-field calculation for the anion.
International Nuclear Information System (INIS)
Adams, T.; Batra, P.; Bugel, Leonard G.; Camilleri, Leslie Loris; Conrad, Janet Marie; Fisher, Peter H.; Formaggio, Joseph Angelo; Karagiorgi, Georgia S.; )
2009-01-01
We extend the physics case for a new high-energy, ultra-high statistics neutrino scattering experiment, NuSOnG (Neutrino Scattering On Glass) to address a variety of issues including precision QCD measurements, extraction of structure functions, and the derived Parton Distribution Functions (PDFs). This experiment uses a Tevatron-based neutrino beam to obtain a sample of Deep Inelastic Scattering (DIS) events which is over two orders of magnitude larger than past samples. We outline an innovative method for fitting the structure functions using a parameterized energy shift which yields reduced systematic uncertainties. High statistics measurements, in combination with improved systematics, will enable NuSOnG to perform discerning tests of fundamental Standard Model parameters as we search for deviations which may hint of 'Beyond the Standard Model' physics
A low-energy β-function in a finite super-Yang-Mills model with multiple mass scales
International Nuclear Information System (INIS)
Foda, O.; Helayel-Neto, J.A.
1985-01-01
We compute the one-loop contribution to the low-energy light-fermion gauge coupling in a finite supersymmetric gauge theory with two mass scales: a heavy mass that breaks an initial N=4 supersymmetry down to N=2, but respects the finiteness, and a light mass that, for simplicity, is set to zero. We find that coupling grows with the mass of the heavy intermediate states. Hence the latter do not decouple at low energies, leading to large logarithms that invalidate low-energy perturbation theory. Consequently, further manipulations are required to obtain a meaningful perturbative expansion. Enforcing decoupling through finite renormalizations, that absorb the heavy mass effects into a redefinition of the parameters of the lagrangian, introduces an arbitrary subtraction mass μ. The requirement that the S-matrix elements be independent of μ leads to a non-trivial renormalization-group equation for the low-energy theory, with a non-vanishing β-function. (orig.)
Low-energy. beta. -function in a finite super-Yang-Mills model with multiple mass scales
Energy Technology Data Exchange (ETDEWEB)
Foda, O.; Helayel-Neto, J.A. (International Centre for Theoretical Physics, Trieste (Italy))
1985-02-14
We compute the one-loop contribution to the low-energy light-fermion gauge coupling in a finite supersymmetric gauge theory with two mass scales: a heavy mass that breaks an initial N=4 supersymmetry down to N=2, but respects the finiteness, and a light mass that, for simplicity, is set to zero. We find that coupling grows with the mass of the heavy intermediate states. Hence the latter do not decouple at low energies, leading to large logarithms that invalidate low-energy perturbation theory. Consequently, further manipulations are required to obtain a meaningful perturbative expansion. Enforcing decoupling through finite renormalizations, that absorb the heavy mass effects into a redefinition of the parameters of the lagrangian, introduces an arbitrary subtraction mass ..mu... The requirement that the S-matrix elements be independent of ..mu.. leads to a non-trivial renormalization-group equation for the low-energy theory, with a non-vanishing ..beta..-function.
General Retarded Contact Self-energies in and beyond the Non-equilibrium Green's Functions Method
International Nuclear Information System (INIS)
Kubis, Tillmann; He, Yu; Andrawis, Robert; Klimeck, Gerhard
2016-01-01
Retarded contact self-energies in the framework of nonequilibrium Green's functions allow to model the impact of lead structures on the device without explicitly including the leads in the actual device calculation. Most of the contact self-energy algorithms are limited to homogeneous or periodic, semi-infinite lead structures. In this work, the complex absorbing potential method is extended to solve retarded contact self-energies for arbitrary lead structures, including irregular and randomly disordered leads. This method is verified for regular leads against common approaches and on physically equivalent, but numerically different irregular leads. Transmission results on randomly alloyed In 0.5 Ga 0.5 As structures show the importance of disorder in the leads. The concept of retarded contact self-energies is expanded to model passivation of atomically resolved surfaces without explicitly increasing the device's Hamiltonian. (paper)
Evolution of elliptic and triangular flow as a function of beam energy in a hybrid model
International Nuclear Information System (INIS)
Auvinen, J; Petersen, H
2014-01-01
Elliptic flow has been one of the key observables for establishing the finding of the quark-gluon plasma (QGP) at the highest energies of Relativistic Heavy Ion Collider (RHIC) and the Large Hadron Collider (LHC). As a sign of collectively behaving matter, one would expect the elliptic flow to decrease at lower beam energies, where the QGP is not produced. However, in the recent RHIC beam energy scan, it has been found that the inclusive charged hadron elliptic flow changes relatively little in magnitude in the energies between 7.7 and 39 GeV per nucleon-nucleon collision. We study the collision energy dependence of the elliptic and triangular flow utilizing a Boltzmann + hydrodynamics hybrid model. Such a hybrid model provides a natural framework for the transition from high collision energies, where the hydrodynamical description is essential, to smaller energies, where the hadron transport dominates. This approach is thus suitable to investigate the relative importance of these two mechanisms for the production of the collective flow at different values of beam energy. Extending the examined range down to 5 GeV per nucleon-nucleon collision allows also making predictions for the CBM experiment at FAIR.
Hybrid Density Functional Study of the Local Structures and Energy Levels of CaAl2O4:Ce3.
Lou, Bibo; Jing, Weiguo; Lou, Liren; Zhang, Yongfan; Yin, Min; Duan, Chang-Kui
2018-05-03
First-principles calculations were carried out for the electronic structures of Ce 3+ in calcium aluminate phosphors, CaAl 2 O 4 , and their effects on luminescence properties. Hybrid density functional approaches were used to overcome the well-known underestimation of band gaps of conventional density functional approaches and to calculate the energy levels of Ce 3+ ions more accurately. The obtained 4f-5d excitation and emission energies show good consistency with measured values. A detailed energy diagram of all three sites is obtained, which explains qualitatively all of the luminescent phenomena. With the results of energy levels calculated by combining the hybrid functional of Heyd, Scuseria, and Ernzerhof (HSE06) and the constraint occupancy approach, we are able to construct a configurational coordinate diagram to analyze the processes of capture of a hole or an electron and luminescence. This approach can be applied for systematic high-throughput calculations in predicting Ce 3+ activated luminescent materials with a moderate computing requirement.
Kolmann, Stephen J.; Jordan, Meredith J. T.
2010-02-01
One of the largest remaining errors in thermochemical calculations is the determination of the zero-point energy (ZPE). The fully coupled, anharmonic ZPE and ground state nuclear wave function of the SSSH radical are calculated using quantum diffusion Monte Carlo on interpolated potential energy surfaces (PESs) constructed using a variety of method and basis set combinations. The ZPE of SSSH, which is approximately 29 kJ mol-1 at the CCSD(T)/6-31G∗ level of theory, has a 4 kJ mol-1 dependence on the treatment of electron correlation. The anharmonic ZPEs are consistently 0.3 kJ mol-1 lower in energy than the harmonic ZPEs calculated at the Hartree-Fock and MP2 levels of theory, and 0.7 kJ mol-1 lower in energy at the CCSD(T)/6-31G∗ level of theory. Ideally, for sub-kJ mol-1 thermochemical accuracy, ZPEs should be calculated using correlated methods with as big a basis set as practicable. The ground state nuclear wave function of SSSH also has significant method and basis set dependence. The analysis of the nuclear wave function indicates that SSSH is localized to a single symmetry equivalent global minimum, despite having sufficient ZPE to be delocalized over both minima. As part of this work, modifications to the interpolated PES construction scheme of Collins and co-workers are presented.
Kolmann, Stephen J; Jordan, Meredith J T
2010-02-07
One of the largest remaining errors in thermochemical calculations is the determination of the zero-point energy (ZPE). The fully coupled, anharmonic ZPE and ground state nuclear wave function of the SSSH radical are calculated using quantum diffusion Monte Carlo on interpolated potential energy surfaces (PESs) constructed using a variety of method and basis set combinations. The ZPE of SSSH, which is approximately 29 kJ mol(-1) at the CCSD(T)/6-31G* level of theory, has a 4 kJ mol(-1) dependence on the treatment of electron correlation. The anharmonic ZPEs are consistently 0.3 kJ mol(-1) lower in energy than the harmonic ZPEs calculated at the Hartree-Fock and MP2 levels of theory, and 0.7 kJ mol(-1) lower in energy at the CCSD(T)/6-31G* level of theory. Ideally, for sub-kJ mol(-1) thermochemical accuracy, ZPEs should be calculated using correlated methods with as big a basis set as practicable. The ground state nuclear wave function of SSSH also has significant method and basis set dependence. The analysis of the nuclear wave function indicates that SSSH is localized to a single symmetry equivalent global minimum, despite having sufficient ZPE to be delocalized over both minima. As part of this work, modifications to the interpolated PES construction scheme of Collins and co-workers are presented.
Within-day energy deficiency and reproductive function in female endurance athletes.
Fahrenholtz, I L; Sjödin, A; Benardot, D; Tornberg, Å B; Skouby, S; Faber, J; Sundgot-Borgen, J K; Melin, A K
2018-03-01
We aimed to estimate and compare within-day energy balance (WDEB) in athletes with eumenorrhea and menstrual dysfunction (MD) with similar 24-hour energy availability/energy balance (EA/EB). Furthermore, to investigate whether within-day energy deficiency is associated with resting metabolic rate (RMR), body composition, S-cortisol, estradiol, T 3 , and fasting blood glucose. We reanalyzed 7-day dietary intake and energy expenditure data in 25 elite endurance athletes with eumenorrhea (n = 10) and MD (n = 15) from a group of 45 subjects where those with disordered eating behaviors (n = 11), MD not related to low EA (n = 5), and low dietary record validity (n = 4) had been excluded. Besides gynecological examination and disordered eating evaluation, the protocol included RMR measurement; assessment of body composition by dual-energy X-ray absorptiometry, blood plasma analysis, and calculation of WDEB in 1-hour intervals. Subjects with MD spent more hours in a catabolic state compared to eumenorrheic athletes; WDEB energy deficiency was associated with clinical markers of metabolic disturbances. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.
International Nuclear Information System (INIS)
Seo, Sang-Hun; In, Jung-Hwan; Chang, Hong-Young
2005-01-01
The temporal behaviour of the electron energy distribution function (EEDF) and the plasma parameters such as electron density, electron temperature and plasma and floating potentials in a mid-frequency pulsed dc magnetron plasma are investigated using time-resolved probe measurements. A negative-voltage dc pulse with an average power of 160 W during the pulse-on period, a repetition frequency of 20 kHz and a duty cycle of 50% is applied to the cathode of a planar unbalanced magnetron discharge with a grounded substrate. The measured electron energy distribution is found to exhibit a bi-Maxwellian distribution, which can be resolved with the low-energy electron group and the high-energy tail part during the pulse-on period, and a Maxwellian distribution only with low-energy electrons as a consequence of initially rapid decay of the high-energy tail part during the pulse-off period. This characteristic evolution of the EEDF is reflected in the decay characteristics of the electron density and temperature in the afterglow. These parameters exhibit twofold decay represented by two characteristic decay times of an initial fast decay time τ 1 , and a subsequent slower decay time τ 2 in the afterglow when approximated with a bi-exponential function. While the initial fast decay times are of the order of 1 μs (τ T1 ∼ 0.99 μs and τ N1 ∼ 1.5 μs), the slower decay times are of the order of a few tens of microseconds (τ T2 ∼ 7 μs and τ N2 ∼ 40 μs). The temporal evolution of the plasma parameters are qualitatively explained by considering the formation mechanism of the bi-Maxwellian electron distribution function and the electron transports of these electron groups in bulk plasma
Mielke, Alexander; Mittnenzweig, Markus
2018-04-01
We discuss how the recently developed energy dissipation methods for reaction diffusion systems can be generalized to the non-isothermal case. For this, we use concave entropies in terms of the densities of the species and the internal energy, where the importance is that the equilibrium densities may depend on the internal energy. Using the log-Sobolev estimate and variants for lower-order entropies as well as estimates for the entropy production of the nonlinear reactions, we give two methods to estimate the relative entropy by the total entropy production, namely a somewhat restrictive convexity method, which provides explicit decay rates, and a very general, but weaker compactness method.
Song, Mengmeng; Cheng, Mengjiao; Ju, Guannan; Zhang, Yajun; Shi, Feng
2014-11-05
A smart device that can dive or surface in aqueous medium has been developed by combining a pH-responsive surface with acid-responsive magnesium. The diving-surfacing cycles can be used to convert chemical energy into electricity. During the diving-surfacing motion, the smart device cuts magnetic flux lines and produces a current, demonstrating that motional energy can be realized by consuming chemical energy of magnesium, thus producing electricity. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Directory of Open Access Journals (Sweden)
Hahnbeom Park
Full Text Available Protein loop modeling is a tool for predicting protein local structures of particular interest, providing opportunities for applications involving protein structure prediction and de novo protein design. Until recently, the majority of loop modeling methods have been developed and tested by reconstructing loops in frameworks of experimentally resolved structures. In many practical applications, however, the protein loops to be modeled are located in inaccurate structural environments. These include loops in model structures, low-resolution experimental structures, or experimental structures of different functional forms. Accordingly, discrepancies in the accuracy of the structural environment assumed in development of the method and that in practical applications present additional challenges to modern loop modeling methods. This study demonstrates a new strategy for employing a hybrid energy function combining physics-based and knowledge-based components to help tackle this challenge. The hybrid energy function is designed to combine the strengths of each energy component, simultaneously maintaining accurate loop structure prediction in a high-resolution framework structure and tolerating minor environmental errors in low-resolution structures. A loop modeling method based on global optimization of this new energy function is tested on loop targets situated in different levels of environmental errors, ranging from experimental structures to structures perturbed in backbone as well as side chains and template-based model structures. The new method performs comparably to force field-based approaches in loop reconstruction in crystal structures and better in loop prediction in inaccurate framework structures. This result suggests that higher-accuracy predictions would be possible for a broader range of applications. The web server for this method is available at http://galaxy.seoklab.org/loop with the PS2 option for the scoring function.
International Nuclear Information System (INIS)
Rees, J.
1986-11-01
Scaling laws for linear colliders are considered for the case of laterally round Gaussian beams and for the case that mutual pinching of the beams can be ignored. Based on these assumptions, the relationship is found between the interaction area, beta function, beam emittance, and energy for a linear collider in order to show the need for substantial improvements in the feasible values of accelerator parameters to reach a center of mass energy of 0.7 TeV. Pinch is then taken into account
Reimers, Jeffrey R; Sajid, A; Kobayashi, Rika; Ford, Michael J
2018-03-13
Defect states in 2-D materials present many possible uses but both experimental and computational characterization of their spectroscopic properties is difficult. We provide and compare results from 13 DFT and ab initio computational methods for up to 25 excited states of a paradigm system, the V N C B defect in hexagonal boron nitride (h-BN). Studied include: (i) potentially catastrophic effects for computational methods arising from the multireference nature of the closed-shell and open-shell states of the defect, which intrinsically involves broken chemical bonds, (ii) differing results from DFT and time-dependent DFT (TDDFT) calculations, (iii) comparison of cluster models to periodic-slab models of the defect, (iv) the starkly differing effects of nuclear relaxation on the various electronic states that control the widths of photoabsorption and photoemission spectra as broken bonds try to heal, (v) the effect of zero-point energy and entropy on free-energy differences, (vi) defect-localized and conduction/valence-band transition natures, and (vii) strategies needed to ensure that the lowest-energy state of a defect can be computationally identified. Averaged state-energy differences of 0.3 eV are found between CCSD(T) and MRCI energies, with thermal effects on free energies sometimes also being of this order. However, DFT-based methods can perform very poorly. Simple generalized-gradient functionals like PBE fail at the most basic level and should never be applied to defect states. Hybrid functionals like HSE06 work very well for excitations within the triplet manifold of the defect, with an accuracy equivalent to or perhaps exceeding the accuracy of the ab initio methods used. However, HSE06 underestimates triplet-state energies by on average of 0.7 eV compared to closed-shell singlet states, while open-shell singlet states are predicted to be too low in energy by 1.0 eV. This leads to misassignment of the ground state of the V N C B defect. Long
Attarian Shandiz, Mohammad; Guinel, Maxime J-F; Ahmadi, Majid; Gauvin, Raynald
2016-02-01
A new approach is presented to introduce the fine structure of core-loss excitations into the electron energy-loss spectra of ionization edges by Monte Carlo simulations based on an optical oscillator model. The optical oscillator strength is refined using the calculated electron energy-loss near-edge structure by density functional theory calculations. This approach can predict the effects of multiple scattering and thickness on the fine structure of ionization edges. In addition, effects of the fitting range for background removal and the integration range under the ionization edge on signal-to-noise ratio are investigated.
High-pressure pair distribution function (PDF) measurement using high-energy focused x-ray beam
Energy Technology Data Exchange (ETDEWEB)
Hong, Xinguo, E-mail: xhong@bnl.gov; Weidner, Donald J. [Mineral Physics Institute, Stony Brook University, Stony Brook, NY 11794 (United States); Ehm, Lars [Mineral Physics Institute, Stony Brook University, Stony Brook, NY 11794 (United States); National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, NY 11973 (United States); Zhong, Zhong; Ghose, Sanjit [National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, NY 11973 (United States); Duffy, Thomas S. [Department of Geosciences, Princeton University, Princeton, NJ 08544 (United States)
2016-07-27
In this paper, we report recent development of the high-pressure pair distribution function (HP-PDF) measurement technique using a focused high-energy X-ray beam coupled with a diamond anvil cell (DAC). The focusing optics consist of a sagittally bent Laue monochromator and Kirkpatrick-Baez (K–B) mirrors. This combination provides a clean high-energy X-ray beam suitable for HP-PDF research. Demonstration of the HP-PDF technique for nanocrystalline platinum under quasi-hydrostatic condition above 30 GPa is presented.
International Nuclear Information System (INIS)
Khericha, Soli T.
2000-01-01
One-energy group, two-dimensional computer code was developed to calculate the response of a detector to a vibrating absorber in a reactor core. A concept of local/global components, based on the frequency dependent detector adjoint function, and a nodalization technique were utilized. The frequency dependent detector adjoint functions presented by complex equations were expanded into real and imaginary parts. In the nodalization technique, the flux is expanded into polynomials about the center point of each node. The phase angle and the magnitude of the one-energy group detector adjoint function were calculated for a detector located in the center of a 200x200 cm reactor using a two-dimensional nodalization technique, the computer code EXTERMINATOR, and the analytical solution. The purpose of this research was to investigate the applicability of a polynomial nodal model technique to the calculations of the real and the imaginary parts of the detector adjoint function for one-energy group two-dimensional polynomial nodal model technique. From the results as discussed earlier, it is concluded that the nodal model technique can be used to calculate the detector adjoint function and the phase angle. Using the computer code developed for nodal model technique, the magnitude of one energy group frequency dependent detector adjoint function and the phase angle were calculated for the detector located in the center of a 200x200 cm homogenous reactor. The real part of the detector adjoint function was compared with the results obtained from the EXTERMINATOR computer code as well as the analytical solution based on a double sine series expansion using the classical Green's Function solution. The values were found to be less than 1% greater at 20 cm away from the source region and about 3% greater closer to the source compared to the values obtained from the analytical solution and the EXTERMINATOR code. The currents at the node interface matched within 1% of the average
Sun, Haitao
2016-05-16
We propose a new methodology for the first-principles description of the electronic properties relevant for charge transport in organic molecular crystals. This methodology, which is based on the combination of a non-empirical, optimally tuned range-separated hybrid functional with the polarizable continuum model, is applied to a series of eight representative molecular semiconductor crystals. We show that it provides ionization energies, electron affinities, and transport gaps in very good agreement with experimental values as well as with the results of many-body perturbation theory within the GW approximation at a fraction of the computational costs. Hence, this approach represents an easily applicable and computationally efficient tool to estimate the gas-to-crystal-phase shifts of the frontier-orbital quasiparticle energies in organic electronic materials.
Study of excitation energy sharing in heavy ion collisions as a function of their inelasticity
International Nuclear Information System (INIS)
Lott, B.
1986-01-01
The excitation energy sharing between the fragments of a heavy ion collision has been studied for quasi-elastic and deep inelastic mechanisms. A 32 S beam of 232 MeV incident energy has been used to bombard several targets (S, 58 Ni, 93 Nb). The evaporated charged particle multiplicities have been measured by inclusive measurements of the projectile-like nuclei and exclusive measurements of the two final nuclei. Evaporation calculations using the Hauser-Feshbach formalism allows us to deduce from the multiplicity measurements the projectile-like excitation energy. These results are compatible with the assumption of an equal sharing of excitation energies for quasi-elastic reaction products, and with the assumption of a mass ratio sharing for fully relaxed reaction products. Limiting values for the relaxation time of this mode have been deduced and are in agreement with predictions from the model developed by Randrup [fr
Beke-Somfai, Tamás; Lincoln, Per; Nordén, Bengt
2010-01-01
Despite exhaustive chemical and crystal structure studies, the mechanistic details of how FoF1-ATP synthase can convert mechanical energy to chemical, producing ATP, are still not fully understood. On the basis of quantum mechanical calculations
Kinetic-energy matrix elements for atomic Hylleraas-CI wave functions
Energy Technology Data Exchange (ETDEWEB)
Harris, Frank E., E-mail: harris@qtp.ufl.edu [Department of Physics, University of Utah, Salt Lake City, Utah 84112, USA and Quantum Theory Project, University of Florida, P.O. Box 118435, Gainesville, Florida 32611 (United States)
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 r{sub ij}. 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.
Evaluation of fitting functions for the representation of an O(3P)+H2 potential energy surface. I
International Nuclear Information System (INIS)
Wagner, A.F.; Schatz, G.C.; Bowman, J.M.
1981-01-01
The DIM surface of Whitlock, Muckerman, and Fisher for the O( 3 P)+H 2 system is used as a test case to evaluate the usefulness of a variety of fitting functions for the representation of potential energy surfaces. Fitting functions based on LEPS, BEBO, and rotated Morse oscillator (RMO) forms are examined. Fitting procedures are developed for combining information about a small portion of the surface and the fitting function to predict where on the surface more information must be obtained to improve the accuracy of the fit. Both unbiased procedures and procedures heavily biased toward the saddle point region of the surface are investigated. Collinear quasiclassical trajectory calculations of the reaction rate constant and one and three dimensional transition state theory rate constant calculations are performed and compared for selected fits and the exact DIM test surface. Fitting functions based on BEBO and RMO forms are found to give quite accurate results
Variation of the binary encounter peak energy as a function of projectile atomic number
International Nuclear Information System (INIS)
Sanders, J.M.
1994-01-01
The energy of the binary encounter peak, in spectra of electrons emitted at 0 degrees with respect to the projectile beam direction, has been studied to investigate its dependence on the atomic number of the projectile ion. The projectiles all had the same squared velocity of 0.6 MeV/u, and all had the same charge q=7. The Z of the projectiles ranged from 8 to 35, and the target was H 2 . The Energy E BEP of the binary encounter peak and also the energy t of the cusp formed by electron loss or electron capture to the projectile continuum (ELC or ECC) were obtained from fits to the spectra. Considerable care was required in fitting the cusp in order to properly ascertain the cusp energy. The energy shift ΔE, defined as the difference between 4t and E BEP , was obtained for each projectile. It is found that the energy shift decreases as the projectile Z increases. This trend is the opposite of that seen for projectile charge where the shift increases as q increases. Such a trend is not well described by the simple elastic scattering model of binary encounter electron production
Tan, Chuang; Guo, Lijun; Ai, Yuejie; Li, Jiang; Wang, Lijuan; Sancar, Aziz; Luo, Yi; Zhong, Dongping
2014-11-13
Photoantenna is essential to energy transduction in photoinduced biological machinery. A photoenzyme, photolyase, has a light-harvesting pigment of methenyltetrahydrofolate (MTHF) that transfers its excitation energy to the catalytic flavin cofactor FADH¯ to enhance DNA-repair efficiency. Here we report our systematic characterization and direct determination of the ultrafast dynamics of resonance energy transfer from excited MTHF to three flavin redox states in E. coli photolyase by capturing the intermediates formed through the energy transfer and thus excluding the electron-transfer quenching pathway. We observed 170 ps for excitation energy transferring to the fully reduced hydroquinone FADH¯, 20 ps to the fully oxidized FAD, and 18 ps to the neutral semiquinone FADH(•), and the corresponding orientation factors (κ(2)) were determined to be 2.84, 1.53 and 1.26, respectively, perfectly matching with our calculated theoretical values. Thus, under physiological conditions and over the course of evolution, photolyase has adopted the optimized orientation of its photopigment to efficiently convert solar energy for repair of damaged DNA.
Wang, Guanyao; Huang, Xingyi; Jiang, Pingkai
2017-01-01
High-dielectric-constant polymer nanocomposites are demonstrated to show great promise as energy storage materials. However, the large electrical mismatch and incompatibility between nanofillers and polymer matrix usually give rise to significantly reduced breakdown strength and weak energy storage capability. Therefore, rational selection and elaborate functionalization of nanofillers to optimize the performance of polymer nanocomposites are vital. Herein, inspired by adhesive proteins in mussels, a facile modification by fluoro-polydopamine is employed to reinforce the compatibility of TiO2 nanowires in the fluoropolymer matrix. The loading of 2.5 vol % f-DOPA@TiO2 NWs leads to an ultrahigh discharged energy density of 11.48 J cm−3 at 530 MV m−1, more than three times of commercial biaxial-oriented polypropylene (BOPP, 3.56 J cm−3 at 600 MV m−1). A gratifying high energy density of 9.12 J cm−3 has also been obtained with nanofiller loading as high as 15 vol % at 360 MV m−1, which is nearly double to that of pure P(VDF-HFP) (4.76 J cm−3 at 360 MV m−1). This splendid energy storage capability seems to rival or exceed most of previously reported nano-TiO2 based nanocomposites. The methods presented here provide deep insights into the design of polymer nanocomposites for energy storage applications. PMID:28225047
Wang, Guanyao; Huang, Xingyi; Jiang, Pingkai
2017-02-01
High-dielectric-constant polymer nanocomposites are demonstrated to show great promise as energy storage materials. However, the large electrical mismatch and incompatibility between nanofillers and polymer matrix usually give rise to significantly reduced breakdown strength and weak energy storage capability. Therefore, rational selection and elaborate functionalization of nanofillers to optimize the performance of polymer nanocomposites are vital. Herein, inspired by adhesive proteins in mussels, a facile modification by fluoro-polydopamine is employed to reinforce the compatibility of TiO2 nanowires in the fluoropolymer matrix. The loading of 2.5 vol % f-DOPA@TiO2 NWs leads to an ultrahigh discharged energy density of 11.48 J cm-3 at 530 MV m-1, more than three times of commercial biaxial-oriented polypropylene (BOPP, 3.56 J cm-3 at 600 MV m-1). A gratifying high energy density of 9.12 J cm-3 has also been obtained with nanofiller loading as high as 15 vol % at 360 MV m-1, which is nearly double to that of pure P(VDF-HFP) (4.76 J cm-3 at 360 MV m-1). This splendid energy storage capability seems to rival or exceed most of previously reported nano-TiO2 based nanocomposites. The methods presented here provide deep insights into the design of polymer nanocomposites for energy storage applications.
Directory of Open Access Journals (Sweden)
H. Mariji
2016-01-01
Full Text Available The nucleon single-particle energies (SPEs of the selected nuclei, that is, O16, Ca40, and Ni56, are obtained by using the diagonal matrix elements of two-body effective interaction, which generated through the lowest-order constrained variational (LOCV calculations for the symmetric nuclear matter with the Aυ18 phenomenological nucleon-nucleon potential. The SPEs at the major levels of nuclei are calculated by employing a Hartree-Fock inspired scheme in the spherical harmonic oscillator basis. In the scheme, the correlation influences are taken into account by imposing the nucleon effective mass factor on the radial wave functions of the major levels. Replacing the density-dependent one-body momentum distribution functions of nucleons, n(k,ρ, with the Heaviside functions, the role of n(k,ρ in the nucleon SPEs at the major levels of the selected closed shell nuclei is investigated. The best fit of spin-orbit splitting is taken into account when correcting the major levels of the nuclei by using the parameterized Wood-Saxon potential and the Aυ18 density-dependent mean field potential which is constructed by the LOCV method. Considering the point-like protons in the spherical Coulomb potential well, the single-proton energies are corrected. The results show the importance of including n(k,ρ, instead of the Heaviside functions, in the calculation of nucleon SPEs at the different levels, particularly the valence levels, of the closed shell nuclei.
International Nuclear Information System (INIS)
Singh, Kumud; Itteera, Janvin; Ukarde, Priti; Teotia, Vikas; Kumar, Prashant; Malhotra, Sanjay; Taly, Y.K.
2013-01-01
Medium Energy Beam Transport (MEBT) line is required to match the optical functions between the RFQ and SRF cavities/DTL cavities.The primary function of the MEBT lines is to keep the emittance growth of the output beam as low as possible in a highly space charge environment at low energies. The transverse focusing of the beam is achieved by strong focusing quadrupoles and the longitudinal dynamics is achieved by the buncher cavities. The Dipole Steerers serve the function of a control element to achieve the desired transverse beam position. To minimize the emittance growth high magnetic field rigidity is required in a highly constrained longitudinal space for these corrector magnets. The design and development of an air-cooled dipole steerer magnet has been done for an integral dipole field of 2.1mT-m in a Good Field Region (GFR) of 23 mm diameter with Integral Field homogeneity better than 0.5%. Electromagnetic field simulations were done using 3D-FEM simulation software OPERA. Error sensitivity studies have been carried out to specify the manufacturing tolerances to estimate and minimize the beam transmission loss due to likely misalignments and rotation of the magnet. A combined function dipole corrector magnet has been designed and fabricated at the Control Instrumentation Division, BARC. This paper discusses measurement results of a combined function dipole steerer for MEBT line for Proton (H + ) beam at 2.5 MeV. (author)
International Nuclear Information System (INIS)
Filippov, G.F.; Ovcharenko, V.I.; Teryoshin, Yu.V.
1980-01-01
For near-magnetic nuclei, the matrix elements of the central exchange nucleon-nucleon interaction potential energy operator between the generating functions of the total basis of the Sn are obtained. The basis states are highest weigt vectorsp(2,R) irreducible representatio of the SO(3) irredicible representation and in addition, have a definite O(A-1) symmetry. The Sp(2,R) basis generating matrix elements simplify essentially the problem of calculating the spectrum of collective excitations of the atomic nucleus over an intrinsic function of definite O(A-1) symmetry
International Nuclear Information System (INIS)
Giricheva, N.I.; Girichev, G.V.; Smorodin, S.V.
2007-01-01
Scanning of potential energy surface in the LaI 3 molecule along normal coordinates are realized using the B3LYP/SDD,SDD method. The most anharmonicity is shown to have a potential function of non-planar oscillation ν 2 (A 2 ''). Effect of anharmonicity on the value of mean-square oscillation amplitudes and oscillation spectrum of the molecule is established. It is noted that the account of anharmonicity of potential functions leads to decreasing mean-square oscillation amplitudes [ru
Veerbeek, Janneke; Firet, Nienke J.; Vijselaar, Wouter; Elbersen, R.; Gardeniers, Han; Huskens, Jurriaan
2017-01-01
Silicon-based solar fuel devices require passivation for optimal performance yet at the same time need functionalization with (photo)catalysts for efficient solar fuel production. Here, we use molecular monolayers to enable electrical passivation and simultaneous functionalization of silicon-based
Directory of Open Access Journals (Sweden)
Hui Yuan
2017-01-01
Full Text Available Interrupted-sampling repeater jamming (ISRJ is a new kind of coherent jamming to the large time-bandwidth linear frequency modulation (LFM signal. Many jamming modes, such as lifelike multiple false targets and dense false targets, can be made through setting up different parameters. According to the “storage-repeater-storage-repeater” characteristics of the ISRJ and the differences in the time-frequency-energy domain between the ISRJ signal and the target echo signal, one new method based on the energy function detection and band-pass filtering is proposed to suppress the ISRJ. The methods mainly consist of two parts: extracting the signal segments without ISRJ and constructing band-pass filtering function with low sidelobe. The simulation results show that the method is effective in the ISRJ with different parameters.
Brain Energy and Oxygen Metabolism: Emerging Role in Normal Function and Disease
Directory of Open Access Journals (Sweden)
Michelle E. Watts
2018-06-01
Full Text Available Dynamic metabolic changes occurring in neurons are critically important in directing brain plasticity and cognitive function. In other tissue types, disruptions to metabolism and the resultant changes in cellular oxidative state, such as increased reactive oxygen species (ROS or induction of hypoxia, are associated with cellular stress. In the brain however, where drastic metabolic shifts occur to support physiological processes, subsequent changes to cellular oxidative state and induction of transcriptional sensors of oxidative stress likely play a significant role in regulating physiological neuronal function. Understanding the role of metabolism and metabolically-regulated genes in neuronal function will be critical in elucidating how cognitive functions are disrupted in pathological conditions where neuronal metabolism is affected. Here, we discuss known mechanisms regulating neuronal metabolism as well as the role of hypoxia and oxidative stress during normal and disrupted neuronal function. We also summarize recent studies implicating a role for metabolism in regulating neuronal plasticity as an emerging neuroscience paradigm.