Second-Order Perturbation Theory for Generalized Active Space Self-Consistent-Field Wave Functions.

Science.gov (United States)

Ma, Dongxia; Li Manni, Giovanni; Olsen, Jeppe; Gagliardi, Laura

2016-07-12

A multireference second-order perturbation theory approach based on the generalized active space self-consistent-field (GASSCF) wave function is presented. Compared with the complete active space (CAS) and restricted active space (RAS) wave functions, GAS wave functions are more flexible and can employ larger active spaces and/or different truncations of the configuration interaction expansion. With GASSCF, one can explore chemical systems that are not affordable with either CASSCF or RASSCF. Perturbation theory to second order on top of GAS wave functions (GASPT2) has been implemented to recover the remaining electron correlation. The method has been benchmarked by computing the chromium dimer ground-state potential energy curve. These calculations show that GASPT2 gives results similar to CASPT2 even with a configuration interaction expansion much smaller than the corresponding CAS expansion.

Quasi-Particle Self-Consistent GW for Molecules.

Science.gov (United States)

Kaplan, F; Harding, M E; Seiler, C; Weigend, F; Evers, F; van Setten, M J

2016-06-14

We present the formalism and implementation of quasi-particle self-consistent GW (qsGW) and eigenvalue only quasi-particle self-consistent GW (evGW) adapted to standard quantum chemistry packages. Our implementation is benchmarked against high-level quantum chemistry computations (coupled-cluster theory) and experimental results using a representative set of molecules. Furthermore, we compare the qsGW approach for five molecules relevant for organic photovoltaics to self-consistent GW results (scGW) and analyze the effects of the self-consistency on the ground state density by comparing calculated dipole moments to their experimental values. We show that qsGW makes a significant improvement over conventional G0W0 and that partially self-consistent flavors (in particular evGW) can be excellent alternatives.

Use of the SSF equations in the Kojima-Moon-Ochi thermodynamic consistency test of isothermal vapour-liquid equilibrium data

Directory of Open Access Journals (Sweden)

SLOBODAN P. SERBANOVIC

2000-12-01

Full Text Available The Kojima-Moon-Ochi (KMO thermodynamic consistency test of vapour–liquid equilibrium (VLE measurements for 32 isothermal data sets of binary systems of various complexity was applied using two fitting equations: the Redlich-Kister equation and the Sum of Symmetrical Functions. It was shown that the enhanced reliability of the fitting of the experimental data can change the conclusions drawn on their thermodynamic consistency in those cases of VLE data sets that are estimated to be near the border of consistency.

Truncated Calogero-Sutherland models

Science.gov (United States)

Pittman, S. M.; Beau, M.; Olshanii, M.; del Campo, A.

2017-05-01

A one-dimensional quantum many-body system consisting of particles confined in a harmonic potential and subject to finite-range two-body and three-body inverse-square interactions is introduced. The range of the interactions is set by truncation beyond a number of neighbors and can be tuned to interpolate between the Calogero-Sutherland model and a system with nearest and next-nearest neighbors interactions discussed by Jain and Khare. The model also includes the Tonks-Girardeau gas describing impenetrable bosons as well as an extension with truncated interactions. While the ground state wave function takes a truncated Bijl-Jastrow form, collective modes of the system are found in terms of multivariable symmetric polynomials. We numerically compute the density profile, one-body reduced density matrix, and momentum distribution of the ground state as a function of the range r and the interaction strength.

Self-consistent radial sheath

International Nuclear Information System (INIS)

Hazeltine, R.D.

1988-12-01

The boundary layer arising in the radial vicinity of a tokamak limiter is examined, with special reference to the TEXT tokamak. It is shown that sheath structure depends upon the self-consistent effects of ion guiding-center orbit modification, as well as the radial variation of E /times/ B-induced toroidal rotation. Reasonable agreement with experiment is obtained from an idealized model which, however simplified, preserves such self-consistent effects. It is argued that the radial sheath, which occurs whenever confining magnetic field-lines lie in the plasma boundary surface, is an object of some intrinsic interest. It differs from the more familiar axial sheath because magnetized charges respond very differently to parallel and perpendicular electric fields. 11 refs., 1 fig

Translationally invariant self-consistent field theories

International Nuclear Information System (INIS)

Shakin, C.M.; Weiss, M.S.

1977-01-01

We present a self-consistent field theory which is translationally invariant. The equations obtained go over to the usual Hartree-Fock equations in the limit of large particle number. In addition to deriving the dynamic equations for the self-consistent amplitudes we discuss the calculation of form factors and various other observables

Self-consistency in Capital Markets

Science.gov (United States)

Benbrahim, Hamid

2013-03-01

Capital Markets are considered, at least in theory, information engines whereby traders contribute to price formation with their diverse perspectives. Regardless whether one believes in efficient market theory on not, actions by individual traders influence prices of securities, which in turn influence actions by other traders. This influence is exerted through a number of mechanisms including portfolio balancing, margin maintenance, trend following, and sentiment. As a result market behaviors emerge from a number of mechanisms ranging from self-consistency due to wisdom of the crowds and self-fulfilling prophecies, to more chaotic behavior resulting from dynamics similar to the three body system, namely the interplay between equities, options, and futures. This talk will address questions and findings regarding the search for self-consistency in capital markets.

Full self-consistency versus quasiparticle self-consistency in diagrammatic approaches: exactly solvable two-site Hubbard model.

Science.gov (United States)

Kutepov, A L

2015-08-12

Self-consistent solutions of Hedin's equations (HE) for the two-site Hubbard model (HM) have been studied. They have been found for three-point vertices of increasing complexity (Γ = 1 (GW approximation), Γ1 from the first-order perturbation theory, and the exact vertex Γ(E)). Comparison is made between the cases when an additional quasiparticle (QP) approximation for Green's functions is applied during the self-consistent iterative solving of HE and when QP approximation is not applied. The results obtained with the exact vertex are directly related to the present open question-which approximation is more advantageous for future implementations, GW + DMFT or QPGW + DMFT. It is shown that in a regime of strong correlations only the originally proposed GW + DMFT scheme is able to provide reliable results. Vertex corrections based on perturbation theory (PT) systematically improve the GW results when full self-consistency is applied. The application of QP self-consistency combined with PT vertex corrections shows similar problems to the case when the exact vertex is applied combined with QP sc. An analysis of Ward Identity violation is performed for all studied in this work's approximations and its relation to the general accuracy of the schemes used is provided.

Quasiparticle self-consistent GW method: a short summary

International Nuclear Information System (INIS)

Kotani, Takao; Schilfgaarde, Mark van; Faleev, Sergey V; Chantis, Athanasios

2007-01-01

We have developed a quasiparticle self-consistent GW method (QSGW), which is a new self-consistent method to calculate the electronic structure within the GW approximation. The method is formulated based on the idea of a self-consistent perturbation; the non-interacting Green function G 0 , which is the starting point for GWA to obtain G, is determined self-consistently so as to minimize the perturbative correction generated by GWA. After self-consistency is attained, we have G 0 , W (the screened Coulomb interaction) and G self-consistently. This G 0 can be interpreted as the optimum non-interacting propagator for the quasiparticles. We will summarize some theoretical discussions to justify QSGW. Then we will survey results which have been obtained up to now: e.g., band gaps for normal semiconductors are predicted to a precision of 0.1-0.3 eV; the self-consistency including the off-diagonal part is required for NiO and MnO; and so on. There are still some remaining disagreements with experiments; however, they are very systematic, and can be explained from the neglect of excitonic effects

Analysis of truncation limit in probabilistic safety assessment

International Nuclear Information System (INIS)

Cepin, Marko

2005-01-01

A truncation limit defines the boundaries of what is considered in the probabilistic safety assessment and what is neglected. The truncation limit that is the focus here is the truncation limit on the size of the minimal cut set contribution at which to cut off. A new method was developed, which defines truncation limit in probabilistic safety assessment. The method specifies truncation limits with more stringency than presenting existing documents dealing with truncation criteria in probabilistic safety assessment do. The results of this paper indicate that the truncation limits for more complex probabilistic safety assessments, which consist of larger number of basic events, should be more severe than presently recommended in existing documents if more accuracy is desired. The truncation limits defined by the new method reduce the relative errors of importance measures and produce more accurate results for probabilistic safety assessment applications. The reduced relative errors of importance measures can prevent situations, where the acceptability of change of equipment under investigation according to RG 1.174 would be shifted from region, where changes can be accepted, to region, where changes cannot be accepted, if the results would be calculated with smaller truncation limit

Self-consistent areas law in QCD

International Nuclear Information System (INIS)

Makeenko, Yu.M.; Migdal, A.A.

1980-01-01

The problem of obtaining the self-consistent areas law in quantum chromodynamics (QCD) is considered from the point of view of the quark confinement. The exact equation for the loop average in multicolor QCD is reduced to a bootstrap form. Its iterations yield new manifestly gauge invariant perturbation theory in the loop space, reproducing asymptotic freedom. For large loops, the areas law apprears to be a self-consistent solution

Nonlinear Ion-Acoustic Waves in a Plasma Consisting of Warm Ions and Isothermal Distributed Electrons

International Nuclear Information System (INIS)

Abourabia, A.M.; Hassan, K.M.; Shahein, R.A.

2008-01-01

The formation of (1+1) dimensional ion-acoustic waves (IAWs) in an unmagnetized collisionless plasma consisting of warm ions and isothermal distributed electrons is investigated. The electrodynamics system of equations are solved analytically in terms of a new variable ξκ χ -φ τ, where k=k(ω) is a complex function, at a fixed position. The analytical calculations gives that the critical value σ = τ/τ ∼ 0.25 distinguishes between the linear and nonlinear characters of IAW within the nanosecond time scale. The flow velocity, pressure, number density, electric potential, electric field, mobility and the total energy in the system are estimated and illustrated

SOCIAL COMPARISON, SELF-CONSISTENCY AND THE PRESENTATION OF SELF.

Science.gov (United States)

MORSE, STANLEY J.; GERGEN, KENNETH J.

TO DISCOVER HOW A PERSON'S (P) SELF-CONCEPT IS AFFECTED BY THE CHARACTERISTICS OF ANOTHER (O) WHO SUDDENLY APPEARS IN THE SAME SOCIAL ENVIRONMENT, SEVERAL QUESTIONNAIRES, INCLUDING THE GERGEN-MORSE (1967) SELF-CONSISTENCY SCALE AND HALF THE COOPERSMITH SELF-ESTEEM INVENTORY, WERE ADMINISTERED TO 78 UNDERGRADUATE MEN WHO HAD ANSWERED AN AD FOR WORK…

Quark-gluon vertex dressing and meson masses beyond ladder-rainbow truncation

International Nuclear Information System (INIS)

Matevosyan, Hrayr H.; Thomas, Anthony W.; Tandy, Peter C.

2007-01-01

We include a generalized infinite class of quark-gluon vertex dressing diagrams in a study of how dynamics beyond the ladder-rainbow truncation influences the Bethe-Salpeter description of light-quark pseudoscalar and vector mesons. The diagrammatic specification of the vertex is mapped into a corresponding specification of the Bethe-Salpeter kernel, which preserves chiral symmetry. This study adopts the algebraic format afforded by the simple interaction kernel used in previous work on this topic. The new feature of the present work is that in every diagram summed for the vertex and the corresponding Bethe-Salpeter kernel, each quark-gluon vertex is required to be the self-consistent vertex solution. We also adopt from previous work the effective accounting for the role of the explicitly non-Abelian three-gluon coupling in a global manner through one parameter determined from recent lattice-QCD data for the vertex. Within the current model, the more consistent dressed vertex limits the ladder-rainbow truncation error for vector mesons to be never more than 10% as the current quark mass is varied from the u/d region to the b region

Adaptation of the delta-m and δ-fit truncation methods to vector radiative transfer: Effect of truncation on radiative transfer accuracy

International Nuclear Information System (INIS)

Sanghavi, Suniti; Stephens, Graeme

2015-01-01

In the presence of aerosol and/or clouds, the use of appropriate truncation methods becomes indispensable for accurate but cost-efficient radiative transfer computations. Truncation methods allow the reduction of the large number (usually several hundreds) of Fourier components associated with particulate scattering functions to a more manageable number, thereby making it possible to carry out radiative transfer computations with a modest number of streams. While several truncation methods have been discussed for scalar radiative transfer, few rigorous studies have been made of truncation methods for the vector case. Here, we formally derive the vector form of Wiscombe's delta-m truncation method. Two main sources of error associated with delta-m truncation are identified as the delta-separation error (DSE) and the phase-truncation error (PTE). The view angles most affected by truncation error occur in the vicinity of the direction of exact backscatter. This view geometry occurs commonly in satellite based remote sensing applications, and is hence of considerable importance. In order to deal with these errors, we adapt the δ-fit approach of Hu et al. (2000) [17] to vector radiative transfer. The resulting δBGE-fit is compared with the vectorized delta-m method. For truncation at l=25 of an original phase matrix consisting of over 300 Fourier components, the use of the δBGE-fit minimizes the error due to truncation at these view angles, while practically eliminating error at other angles. We also show how truncation errors have a distorting effect on hyperspectral absorption line shapes. The choice of the δBGE-fit method over delta-m truncation minimizes errors in absorption line depths, thus affording greater accuracy for sensitive retrievals such as those of XCO 2 from OCO-2 or GOSAT measurements. - Highlights: • Derives vector form for delta-m truncation method. • Adapts δ-fit truncation approach to vector RTE as δBGE-fit. • Compares truncation

Self-consistent model of confinement

International Nuclear Information System (INIS)

Swift, A.R.

1988-01-01

A model of the large-spatial-distance, zero--three-momentum, limit of QCD is developed from the hypothesis that there is an infrared singularity. Single quarks and gluons do not propagate because they have infinite energy after renormalization. The Hamiltonian formulation of the path integral is used to quantize QCD with physical, nonpropagating fields. Perturbation theory in the infrared limit is simplified by the absence of self-energy insertions and by the suppression of large classes of diagrams due to vanishing propagators. Remaining terms in the perturbation series are resummed to produce a set of nonlinear, renormalizable integral equations which fix both the confining interaction and the physical propagators. Solutions demonstrate the self-consistency of the concepts of an infrared singularity and nonpropagating fields. The Wilson loop is calculated to provide a general proof of confinement. Bethe-Salpeter equations for quark-antiquark pairs and for two gluons have finite-energy solutions in the color-singlet channel. The choice of gauge is addressed in detail. Large classes of corrections to the model are discussed and shown to support self-consistency

Coupled Dyson-Schwinger equations and effects of self-consistency

International Nuclear Information System (INIS)

Wu, S.S.; Zhang, H.X.; Yao, Y.J.

2001-01-01

Using the σ-ω model as an effective tool, the effects of self-consistency are studied in some detail. A coupled set of Dyson-Schwinger equations for the renormalized baryon and meson propagators in the σ-ω model is solved self-consistently according to the dressed Hartree-Fock scheme, where the hadron propagators in both the baryon and meson self-energies are required to also satisfy this coupled set of equations. It is found that the self-consistency affects the baryon spectral function noticeably, if only the interaction with σ mesons is considered. However, there is a cancellation between the effects due to the σ and ω mesons and the additional contribution of ω mesons makes the above effect insignificant. In both the σ and σ-ω cases the effects of self-consistency on meson spectral function are perceptible, but they can nevertheless be taken account of without a self-consistent calculation. Our study indicates that to include the meson propagators in the self-consistency requirement is unnecessary and one can stop at an early step of an iteration procedure to obtain a good approximation to the fully self-consistent results of all the hadron propagators in the model, if an appropriate initial input is chosen. Vertex corrections and their effects on ghost poles are also studied

Helicase Dependent Isothermal Amplification of DNA and RNA using Self-Avoiding Molecular Recognition Systems

Science.gov (United States)

Yang, Zunyi; McLendon, Chris; Hutter, Daniel; Bradley, Kevin M.; Hoshika, Shuichi; Frye, Carole; Benner, Steven A.

2015-01-01

Assays that target DNA or RNA (xNA) are highly sensitive, as small amounts of xNA can be amplified by PCR. Unfortunately, PCR is inconvenient in low resource environments, requiring equipment and power that may not be available in these environments. However, isothermal procedures that avoid thermal cycling are often confounded by primer dimers, off-target priming, and other artifacts. Here, we show how a “self avoiding molecular recognition system” (SAMRS) eliminates these artifacts to give clean amplicons in a helicase-dependent isothermal amplification (SAMRS-HDA). We also show that incorporating SAMRS into the 3′-ends of primers facilitates the design and screening of primers for HDA assays. Finally, we show that SAMRS-HDA can be twofold multiplexed, something difficult to achieve with HDA using standard primers. This shows that SAMRS-HDA is a more versatile approach than standard HDA with a broader applicability for xNA-targeted diagnostics and research. PMID:25953623

Self-consistency and coherent effects in nonlinear resonances

International Nuclear Information System (INIS)

Hofmann, I.; Franchetti, G.; Qiang, J.; Ryne, R. D.

2003-01-01

The influence of space charge on emittance growth is studied in simulations of a coasting beam exposed to a strong octupolar perturbation in an otherwise linear lattice, and under stationary parameters. We explore the importance of self-consistency by comparing results with a non-self-consistent model, where the space charge electric field is kept 'frozen-in' to its initial values. For Gaussian distribution functions we find that the 'frozen-in' model results in a good approximation of the self-consistent model, hence coherent response is practically absent and the emittance growth is self-limiting due to space charge de-tuning. For KV or waterbag distributions, instead, strong coherent response is found, which we explain in terms of absence of Landau damping

Self-consistency corrections in effective-interaction calculations

International Nuclear Information System (INIS)

Starkand, Y.; Kirson, M.W.

1975-01-01

Large-matrix extended-shell-model calculations are used to compute self-consistency corrections to the effective interaction and to the linked-cluster effective interaction. The corrections are found to be numerically significant and to affect the rate of convergence of the corresponding perturbation series. The influence of various partial corrections is tested. It is concluded that self-consistency is an important effect in determining the effective interaction and improving the rate of convergence. (author)

Self-consistent cluster theories for alloys with diagonal and off-diagonal disorder

International Nuclear Information System (INIS)

Gonis, A.; Garland, J.W.

1978-01-01

The molecular coherent-potential approximation (MCPA) and other, simpler cluster approximations for disordered alloys are studied both analytically and numerically for alloys with diagonal and off-diagonal disorder (ODD). First, the MCPA for alloys with only diagonal disorder is rederived within the interactor formalism of Blackman, Esterling, and Berk. This formalism, which simplifies the numerical implementation of the MCPA, is then used to generalize the MCPA so as to take account of ODD. It is shown that the analytic properties of the MCPA are preserved under this generalization. Also, two computationally simple cluster approximations, the self-consistent central-site approximation (SCCSA) and the self-consistent boundary-site approximation (SCBSA), are generalized to include the effects of ODD. It is shown that for one-dimensional systems with only nearest-neighbor hopping the SCBSA yields Green's functions which are identical to those given by the MCPA and thus are analytic, even in the presence of ODD. Finally, the results of numerical calculations are reported for one-dimensional systems with only nearest-neighbor hopping but with both diagonal and off-diagonal disorder. These calculations were performed using the single-site approximation of Blackman, Esterling, and Berk and three different cluster approximations: the multishell method previously proposed by the authors, the SCCSA, and the SCBSA. The results of these calculations are compared with exact results and with previous results obtained using the truncated t-matix approximation and the recent method of Kaplan and Gray. These comparisons suggest that the multishell method and the generalization of the SCBSA given in this paper are more efficient and accurate for the calculation of densities of states for systems with ODD. On the other hand, as expected, the SCCSA was found to yield severely nonanalytic results for the values of band parameters used

Self-consistent approximations beyond the CPA: Part II

International Nuclear Information System (INIS)

Kaplan, T.; Gray, L.J.

1982-01-01

This paper concentrates on a self-consistent approximation for random alloys developed by Kaplan, Leath, Gray, and Diehl. The construction of the augmented space formalism for a binary alloy is sketched, and the notation to be used derived. Using the operator methods of the augmented space, the self-consistent approximation is derived for the average Green's function, and for evaluating the self-energy, taking into account the scattering by clusters of excitations. The particular cluster approximation desired is derived by treating the scattering by the excitations with S /SUB T/ exactly. Fourier transforms on the disorder-space clustersite labels solve the self-consistent set of equations. Expansion to short range order in the alloy is also discussed. A method to reduce the problem to a computationally tractable form is described

Investigation of propagation dynamics of truncated vector vortex beams.

Science.gov (United States)

Srinivas, P; Perumangatt, C; Lal, Nijil; Singh, R P; Srinivasan, B

2018-06-01

In this Letter, we experimentally investigate the propagation dynamics of truncated vector vortex beams generated using a Sagnac interferometer. Upon focusing, the truncated vector vortex beam is found to regain its original intensity structure within the Rayleigh range. In order to explain such behavior, the propagation dynamics of a truncated vector vortex beam is simulated by decomposing it into the sum of integral charge beams with associated complex weights. We also show that the polarization of the truncated composite vector vortex beam is preserved all along the propagation axis. The experimental observations are consistent with theoretical predictions based on previous literature and are in good agreement with our simulation results. The results hold importance as vector vortex modes are eigenmodes of the optical fiber.

Self-consistent calculation of atomic structure for mixture

International Nuclear Information System (INIS)

Meng Xujun; Bai Yun; Sun Yongsheng; Zhang Jinglin; Zong Xiaoping

2000-01-01

Based on relativistic Hartree-Fock-Slater self-consistent average atomic model, atomic structure for mixture is studied by summing up component volumes in mixture. Algorithmic procedure for solving both the group of Thomas-Fermi equations and the self-consistent atomic structure is presented in detail, and, some numerical results are discussed

Maximum nondiffracting propagation distance of aperture-truncated Airy beams

Science.gov (United States)

Chu, Xingchun; Zhao, Shanghong; Fang, Yingwu

2018-05-01

Airy beams have called attention of many researchers due to their non-diffracting, self-healing and transverse accelerating properties. A key issue in research of Airy beams and its applications is how to evaluate their nondiffracting propagation distance. In this paper, the critical transverse extent of physically realizable Airy beams is analyzed under the local spatial frequency methodology. The maximum nondiffracting propagation distance of aperture-truncated Airy beams is formulated and analyzed based on their local spatial frequency. The validity of the formula is verified by comparing the maximum nondiffracting propagation distance of an aperture-truncated ideal Airy beam, aperture-truncated exponentially decaying Airy beam and exponentially decaying Airy beam. Results show that the formula can be used to evaluate accurately the maximum nondiffracting propagation distance of an aperture-truncated ideal Airy beam. Therefore, it can guide us to select appropriate parameters to generate Airy beams with long nondiffracting propagation distance that have potential application in the fields of laser weapons or optical communications.

An iterative reconstruction from truncated projection data

International Nuclear Information System (INIS)

Anon.

1985-01-01

Various methods have been proposed for tomographic reconstruction from truncated projection data. In this paper, a reconstructive method is discussed which consists of iterations of filtered back-projection, reprojection and some nonlinear processings. First, the method is so constructed that it converges to a fixed point. Then, to examine its effectiveness, comparisons are made by computer experiments with two existing reconstructive methods for truncated projection data, that is, the method of extrapolation based on the smooth assumption followed by filtered back-projection, and modified additive ART

Self-consistent modelling of resonant tunnelling structures

DEFF Research Database (Denmark)

Fiig, T.; Jauho, A.P.

1992-01-01

We report a comprehensive study of the effects of self-consistency on the I-V-characteristics of resonant tunnelling structures. The calculational method is based on a simultaneous solution of the effective-mass Schrödinger equation and the Poisson equation, and the current is evaluated...... applied voltages and carrier densities at the emitter-barrier interface. We include the two-dimensional accumulation layer charge and the quantum well charge in our self-consistent scheme. We discuss the evaluation of the current contribution originating from the two-dimensional accumulation layer charges......, and our qualitative estimates seem consistent with recent experimental studies. The intrinsic bistability of resonant tunnelling diodes is analyzed within several different approximation schemes....

A Post-Truncation Parameterization of Truncated Normal Technical Inefficiency

OpenAIRE

Christine Amsler; Peter Schmidt; Wen-Jen Tsay

2013-01-01

In this paper we consider a stochastic frontier model in which the distribution of technical inefficiency is truncated normal. In standard notation, technical inefficiency u is distributed as N^+ (μ,σ^2). This distribution is affected by some environmental variables z that may or may not affect the level of the frontier but that do affect the shortfall of output from the frontier. We will distinguish the pre-truncation mean (μ) and variance (σ^2) from the post-truncation mean μ_*=E(u) and var...

Equivalence of truncated count mixture distributions and mixtures of truncated count distributions.

Science.gov (United States)

Böhning, Dankmar; Kuhnert, Ronny

2006-12-01

This article is about modeling count data with zero truncation. A parametric count density family is considered. The truncated mixture of densities from this family is different from the mixture of truncated densities from the same family. Whereas the former model is more natural to formulate and to interpret, the latter model is theoretically easier to treat. It is shown that for any mixing distribution leading to a truncated mixture, a (usually different) mixing distribution can be found so that the associated mixture of truncated densities equals the truncated mixture, and vice versa. This implies that the likelihood surfaces for both situations agree, and in this sense both models are equivalent. Zero-truncated count data models are used frequently in the capture-recapture setting to estimate population size, and it can be shown that the two Horvitz-Thompson estimators, associated with the two models, agree. In particular, it is possible to achieve strong results for mixtures of truncated Poisson densities, including reliable, global construction of the unique NPMLE (nonparametric maximum likelihood estimator) of the mixing distribution, implying a unique estimator for the population size. The benefit of these results lies in the fact that it is valid to work with the mixture of truncated count densities, which is less appealing for the practitioner but theoretically easier. Mixtures of truncated count densities form a convex linear model, for which a developed theory exists, including global maximum likelihood theory as well as algorithmic approaches. Once the problem has been solved in this class, it might readily be transformed back to the original problem by means of an explicitly given mapping. Applications of these ideas are given, particularly in the case of the truncated Poisson family.

Ion-sound oscillations in strongly non-isotherm weakly ionized nonuniform hydrogen plasma

International Nuclear Information System (INIS)

Leleko, Ya.F.; Stepanov, K.N.

2010-01-01

A stationary distribution of strongly non-isotherm weakly ionized hydrogen plasma parameters is obtained in the hydrodynamic approximation in a quasi neutrality region in the transient layer between the plasma and dielectric taking the ionization, charge exchange, diffusion, viscosity, and a self-consistent field potential distribution. The ion-sound oscillation frequency and the collisional damping decrement as functions of the wave vector in the plasma with the obtained parameters are found in the local approximation.

Helicase-Dependent Isothermal Amplification of DNA and RNA by Using Self-Avoiding Molecular Recognition Systems.

Science.gov (United States)

Yang, Zunyi; McLendon, Chris; Hutter, Daniel; Bradley, Kevin M; Hoshika, Shuichi; Frye, Carole B; Benner, Steven A

2015-06-15

Assays that detect DNA or RNA (xNA) are highly sensitive, as small amounts of xNA can be amplified by PCR. Unfortunately, PCR is inconvenient in low-resource environments, and requires equipment and power that might not be available in these environments. Isothermal procedures, which avoid thermal cycling, are often confounded by primer dimers, off-target priming, and other artifacts. Here, we show how a "self avoiding molecular recognition system" (SAMRS) eliminates these artifacts and gives clean amplicons in a helicase-dependent isothermal amplification (SAMRS-HDA). We also show that incorporating SAMRS into the 3'-ends of primers facilitates the design and screening of primers for HDA assays. Finally, we show that SAMRS-HDA can be twofold multiplexed, difficult to achieve with HDA using standard primers. Thus, SAMRS-HDA is a more versatile approach than standard HDA, with a broader applicability for xNA-targeted diagnostics and research. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

How Truncating Are 'Truncating Languages'? Evidence from Russian and German.

Science.gov (United States)

Rathcke, Tamara V

Russian and German have pr eviously been described as 'truncating', or cutting off target frequencies of the phrase-final pitch trajectories when the time available for voicing is compromised. However, supporting evidence is rare and limited to only a few pitch categories. This paper reports a production study conducted to document pitch adjustments to linguistic materials, in which the amount of voicing available for the realization of a pitch pattern varies from relatively long to extremely short. Productions of nuclear H+L*, H* and L*+H pitch accents followed by a low boundary tone were investigated in the two languages. The results of the study show that speakers of both 'truncating languages' do not utilize truncation exclusively when accommodating to different segmental environments. On the contrary, they employ several strategies - among them is truncation but also compression and temporal re-alignment - to produce the target pitch categories under increasing time pressure. Given that speakers can systematically apply all three adjustment strategies to produce some pitch patterns (H* L% in German and Russian) while not using truncation in others (H+L* L% particularly in Russian), we question the effectiveness of the typological classification of these two languages as 'truncating'. Moreover, the phonetic detail of truncation varies considerably, both across and within the two languages, indicating that truncation cannot be easily modeled as a unified phenomenon. The results further suggest that the phrase-final pitch adjustments are sensitive to the phonological composition of the tonal string and the status of a particular tonal event (associated vs. boundary tone), and do not apply to falling vs. rising pitch contours across the board, as previously put forward for German. Implications for the intonational phonology and prosodic typology are addressed in the discussion. © 2017 S. Karger AG, Basel.

Tunneling in cosmology and isothermal inflation

International Nuclear Information System (INIS)

Brout, R.; Spindel, P.

1991-01-01

The wave function for the universe, as proposed by Hartle and Hawking, experiences tunneling for small values of the radius of the universe. This induces thermal effects and so a hot big bang. We first give a detailed analysis of the observer accelerating in Minkowski space in terms of the tunneling of his wave function beyond his turning point. Applied to cosmology one finds a temperature at the big bang equal to the Gibbons-Hawking value. The residual thermal effects which result in an isothermal inflationary expansion give rise to a renormalized self-consistently determined Hubble constant (and hence Gibbons-Hawking temperature) through the trace anomaly. A thermodynamic interpretation is given. These results militate against phase transitions as a motor for inflation. (orig.)

Self-consistent normal ordering of gauge field theories

International Nuclear Information System (INIS)

Ruehl, W.

1987-01-01

Mean-field theories with a real action of unconstrained fields can be self-consistently normal ordered. This leads to a considerable improvement over standard mean-field theory. This concept is applied to lattice gauge theories. First an appropriate real action mean-field theory is constructed. The equations determining the Gaussian kernel necessary for self-consistent normal ordering of this mean-field theory are derived. (author). 4 refs

Parquet equations for numerical self-consistent-field theory

International Nuclear Information System (INIS)

Bickers, N.E.

1991-01-01

In recent years increases in computational power have provided new motivation for the study of self-consistent-field theories for interacting electrons. In this set of notes, the so-called parquet equations for electron systems are derived pedagogically. The principal advantages of the parquet approach are outlined, and its relationship to simpler self-consistent-field methods, including the Baym-Kadanoff technique, is discussed in detail. (author). 14 refs, 9 figs

Liking for Evaluators: Consistency and Self-Esteem Theories

Science.gov (United States)

Regan, Judith Weiner

1976-01-01

Consistency and self-esteem theories make contrasting predictions about the relationship between a person's self-evaluation and his liking for an evaluator. Laboratory experiments confirmed predictions about these theories. (Editor/RK)

Production of valuable pyrolytic oils from mixed Municipal Solid Waste (MSW in Indonesia using non-isothermal and isothermal experimental

Directory of Open Access Journals (Sweden)

Indra Mamad Gandidi

2017-09-01

Full Text Available Municipal solid waste (MSW, disposed of at open dumping sites, poses health risks, contaminates surface water, and releases greenhouse gasses such as methane. However, pyrolysis offers the opportunity to convert MSW into Bio-Oil (BO for clean energy resource. In this paper, an MSW sample consisting of plastic, paper and cardboard, rubber and textiles, and vegetable waste is pyrolysed on a laboratory scale in a fixed-bed vacuum reactor. In the non-isothermal process, the sample was fed into the reactor and then heated. In the isothermal process, the reactor is first heated and then the sample is added. The non-isothermal process created greater BO in both quality and quantity. The BO had a larger amount of gasoline species than diesel-48 fuel, with at 33.44%the BO produced by isothermal pyrolysis and 36.42% in non-isothermal pyrolysis. However the product of isothermal pyrolysis had a higher acid content that reduced its heating value.

R Programs for Truncated Distributions

Directory of Open Access Journals (Sweden)

Saralees Nadarajah

2006-08-01

Full Text Available Truncated distributions arise naturally in many practical situations. In this note, we provide programs for computing six quantities of interest (probability density function, mean, variance, cumulative distribution function, quantile function and random numbers for any truncated distribution: whether it is left truncated, right truncated or doubly truncated. The programs are written in R: a freely downloadable statistical software.

Exact relations for energy transfer in self-gravitating isothermal turbulence.

Science.gov (United States)

Banerjee, Supratik; Kritsuk, Alexei G

2017-11-01

Self-gravitating isothermal supersonic turbulence is analyzed in the asymptotic limit of large Reynolds numbers. Based on the inviscid invariance of total energy, an exact relation is derived for homogeneous (not necessarily isotropic) turbulence. A modified definition for the two-point energy correlation functions is used to comply with the requirement of detailed energy equipartition in the acoustic limit. In contrast to the previous relations (S. Galtier and S. Banerjee, Phys. Rev. Lett. 107, 134501 (2011)PRLTAO0031-900710.1103/PhysRevLett.107.134501; S. Banerjee and S. Galtier, Phys. Rev. E 87, 013019 (2013)PLEEE81539-375510.1103/PhysRevE.87.013019), the current exact relation shows that the pressure dilatation terms play practically no role in the energy cascade. Both the flux and source terms are written in terms of two-point differences. Sources enter the relation in a form of mixed second-order structure functions. Unlike the kinetic and thermodynamic potential energies, the gravitational contribution is absent from the flux term. An estimate shows that, for the isotropic case, the correlation between density and gravitational acceleration may play an important role in modifying the energy transfer in self-gravitating turbulence. The exact relation is also written in an alternative form in terms of two-point correlation functions, which is then used to describe scale-by-scale energy budget in spectral space.

Family Therapy for the "Truncated" Nuclear Family.

Science.gov (United States)

Zuk, Gerald H.

1980-01-01

The truncated nuclear family consists of a two-generation group in which conflict has produced a polarization of values. The single-parent family is at special risk. Go-between process enables the therapist to depolarize sharply conflicted values and reduce pathogenic relating. (Author)

Understand rotating isothermal collapses yet

International Nuclear Information System (INIS)

Tohline, J.E.

1985-01-01

A scalar virial equation is used to describe the dynamic properties of equilibrium gas clouds, taking into account the relative effects of surface pressure, rotation, self gravity and internal isothermal pressure. Details concerning the internal structure of the clouds are ignored in order to obtain a globalized analytical expression. The obtained solution to the equation is found to agree with the surface-pressure-dominated model of Stahler (1983), and the rotation-dominated model of Hayashi, Narita, and Miyama (1982). On the basis of the analytical expression of virial equilibrium in the clouds, some of the limiting properties of isothermal clouds are described, and a realistic starting model for cloud collapse is proposed. 18 references

Linear augmented plane wave method for self-consistent calculations

International Nuclear Information System (INIS)

Takeda, T.; Kuebler, J.

1979-01-01

O.K. Andersen has recently introduced a linear augmented plane wave method (LAPW) for the calculation of electronic structure that was shown to be computationally fast. A more general formulation of an LAPW method is presented here. It makes use of a freely disposable number of eigenfunctions of the radial Schroedinger equation. These eigenfunctions can be selected in a self-consistent way. The present formulation also results in a computationally fast method. It is shown that Andersen's LAPW is obtained in a special limit from the present formulation. Self-consistent test calculations for copper show the present method to be remarkably accurate. As an application, scalar-relativistic self-consistent calculations are presented for the band structure of FCC lanthanum. (author)

Isothermal Titration Calorimetry and Fluorescence Spectroscopy Study Of Asphaltene Self-Association In Toluene And Interaction With A Model Resin

DEFF Research Database (Denmark)

Garcia, Daniel Merino; Andersen, Simon Ivar

2002-01-01

This article collects the work performed by Isothermal Titration Caloritnetry (ITC) in the study of the self-association of asphaltenes in toluene solutions. Calorimetric experiments show that asphaltenes, start self-associating at very low concentrations and that the existence of a Critical...... with the results of the titration of three model molecules: nonylphenol, which associates by means of hydrogen bond formation, and coronene and pyrene, which associates by stacking. The results obtained leave open the question about the model-stacking molecules, as it was not possible to elucidate whether they do...

A self-consistent theory of the magnetic polaron

International Nuclear Information System (INIS)

Marvakov, D.I.; Kuzemsky, A.L.; Vlahov, J.P.

1984-10-01

A finite temperature self-consistent theory of magnetic polaron in the s-f model of ferromagnetic semiconductors is developed. The calculations are based on the novel approach of the thermodynamic two-time Green function methods. This approach consists in the introduction of the ''irreducible'' Green functions (IGF) and derivation of the exact Dyson equation and exact self-energy operator. It is shown that IGF method gives a unified and natural approach for a calculation of the magnetic polaron states by taking explicitly into account the damping effects and finite lifetime. (author)

Self-consistent electrodynamic scattering in the symmetric Bragg case

International Nuclear Information System (INIS)

Campos, H.S.

1988-01-01

We have analyzed the symmetric Bragg case, introducing a model of self consistent scattering for two elliptically polarized beams. The crystal is taken as a set of mathematical planes, each of them defined by a surface density of dipoles. We have considered the mesofield and the epifield differently from that of the Ewald's theory and, we assumed a plane of dipoles and the associated fields as a self consistent scattering unit. The exact analytical treatment when applied to any two neighbouring planes, results in a general and self consistent Bragg's equation, in terms of the amplitude and phase variations. The generalized solution for the set of N planes was obtained after introducing an absorption factor in the incident radiation, in two ways: (i) the analytical one, through a rule of field similarity, which says that the incidence occurs in both faces of the all crystal planes and also, through a matricial development with the Chebyshev polynomials; (ii) using the numerical solution we calculated, iteratively, the reflectivity, the reflection phase, the transmissivity, the transmission phase and the energy. The results are showed through reflection and transmission curves, which are characteristics as from kinematical as dynamical theories. The conservation of the energy results from the Ewald's self consistency principle is used. In the absorption case, the results show that it is not the only cause for the asymmetric form in the reflection curves. The model contains basic elements for a unified, microscope, self consistent, vectorial and exact formulation for interpretating the X ray diffraction in perfect crystals. (author)

Efficient self-consistency for magnetic tight binding

Science.gov (United States)

Soin, Preetma; Horsfield, A. P.; Nguyen-Manh, D.

2011-06-01

Tight binding can be extended to magnetic systems by including an exchange interaction on an atomic site that favours net spin polarisation. We have used a published model, extended to include long-ranged Coulomb interactions, to study defects in iron. We have found that achieving self-consistency using conventional techniques was either unstable or very slow. By formulating the problem of achieving charge and spin self-consistency as a search for stationary points of a Harris-Foulkes functional, extended to include spin, we have derived a much more efficient scheme based on a Newton-Raphson procedure. We demonstrate the capabilities of our method by looking at vacancies and self-interstitials in iron. Self-consistency can indeed be achieved in a more efficient and stable manner, but care needs to be taken to manage this. The algorithm is implemented in the code PLATO. Program summaryProgram title:PLATO Catalogue identifier: AEFC_v2_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEFC_v2_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 228 747 No. of bytes in distributed program, including test data, etc.: 1 880 369 Distribution format: tar.gz Programming language: C and PERL Computer: Apple Macintosh, PC, Unix machines Operating system: Unix, Linux, Mac OS X, Windows XP Has the code been vectorised or parallelised?: Yes. Up to 256 processors tested RAM: Up to 2 Gbytes per processor Classification: 7.3 External routines: LAPACK, BLAS and optionally ScaLAPACK, BLACS, PBLAS, FFTW Catalogue identifier of previous version: AEFC_v1_0 Journal reference of previous version: Comput. Phys. Comm. 180 (2009) 2616 Does the new version supersede the previous version?: Yes Nature of problem: Achieving charge and spin self-consistency in magnetic tight binding can be very

Self-consistent hybrid functionals for solids: a fully-automated implementation

Science.gov (United States)

Erba, A.

2017-08-01

A fully-automated algorithm for the determination of the system-specific optimal fraction of exact exchange in self-consistent hybrid functionals of the density-functional-theory is illustrated, as implemented into the public Crystal program. The exchange fraction of this new class of functionals is self-consistently updated proportionally to the inverse of the dielectric response of the system within an iterative procedure (Skone et al 2014 Phys. Rev. B 89, 195112). Each iteration of the present scheme, in turn, implies convergence of a self-consistent-field (SCF) and a coupled-perturbed-Hartree-Fock/Kohn-Sham (CPHF/KS) procedure. The present implementation, beside improving the user-friendliness of self-consistent hybrids, exploits the unperturbed and electric-field perturbed density matrices from previous iterations as guesses for subsequent SCF and CPHF/KS iterations, which is documented to reduce the overall computational cost of the whole process by a factor of 2.

Self-consistent one-gluon exchange in soliton bag models

International Nuclear Information System (INIS)

Dodd, L.R.; Adelaide Univ.; Williams, A.G.

1988-01-01

The treatment of soliton bag models as two-point boundary value problems is extended to include self-consistent one-gluon exchange interactions. The colour-magnetic contribution to the nucleon-delta mass splitting is calculated self-consistently in the mean-field, one-gluon-exchange approximation for the Friedberg-Lee and Nielsen-Patkos models. Small glueball mass parameters (m GB ∝ 500 MeV) are favoured. Comparisons with previous calculations are made. (orig.)

Zero-truncated negative binomial - Erlang distribution

Science.gov (United States)

Bodhisuwan, Winai; Pudprommarat, Chookait; Bodhisuwan, Rujira; Saothayanun, Luckhana

2017-11-01

The zero-truncated negative binomial-Erlang distribution is introduced. It is developed from negative binomial-Erlang distribution. In this work, the probability mass function is derived and some properties are included. The parameters of the zero-truncated negative binomial-Erlang distribution are estimated by using the maximum likelihood estimation. Finally, the proposed distribution is applied to real data, the number of methamphetamine in the Bangkok, Thailand. Based on the results, it shows that the zero-truncated negative binomial-Erlang distribution provided a better fit than the zero-truncated Poisson, zero-truncated negative binomial, zero-truncated generalized negative-binomial and zero-truncated Poisson-Lindley distributions for this data.

Angular truncation errors in integrating nephelometry

International Nuclear Information System (INIS)

Moosmueller, Hans; Arnott, W. Patrick

2003-01-01

Ideal integrating nephelometers integrate light scattered by particles over all directions. However, real nephelometers truncate light scattered in near-forward and near-backward directions below a certain truncation angle (typically 7 deg. ). This results in truncation errors, with the forward truncation error becoming important for large particles. Truncation errors are commonly calculated using Mie theory, which offers little physical insight and no generalization to nonspherical particles. We show that large particle forward truncation errors can be calculated and understood using geometric optics and diffraction theory. For small truncation angles (i.e., <10 deg. ) as typical for modern nephelometers, diffraction theory by itself is sufficient. Forward truncation errors are, by nearly a factor of 2, larger for absorbing particles than for nonabsorbing particles because for large absorbing particles most of the scattered light is due to diffraction as transmission is suppressed. Nephelometers calibration procedures are also discussed as they influence the effective truncation error

Near-resonant absorption in the time-dependent self-consistent field and multiconfigurational self-consistent field approximations

DEFF Research Database (Denmark)

Norman, Patrick; Bishop, David M.; Jensen, Hans Jørgen Aa

2001-01-01

Computationally tractable expressions for the evaluation of the linear response function in the multiconfigurational self-consistent field approximation were derived and implemented. The finite lifetime of the electronically excited states was considered and the linear response function was shown...... to be convergent in the whole frequency region. This was achieved through the incorporation of phenomenological damping factors that lead to complex response function values....

Self-consistent equilibria in the pulsar magnetosphere

International Nuclear Information System (INIS)

Endean, V.G.

1976-01-01

For a 'collisionless' pulsar magnetosphere the self-consistent equilibrium particle distribution functions are functions of the constants of the motion ony. Reasons are given for concluding that to a good approximation they will be functions of the rotating frame Hamiltonian only. This is shown to result in a rigid rotation of the plasma, which therefore becomes trapped inside the velocity of light cylinder. The self-consistent field equations are derived, and a method of solving them is illustrated. The axial component of the magnetic field decays to zero at the plasma boundary. In practice, some streaming of particles into the wind zone may occur as a second-order effect. Acceleration of such particles to very high energies is expected when they approach the velocity of light cylinder, but they cannot be accelerated to very high energies near the star. (author)

An approach to a self-consistent nuclear energy system

International Nuclear Information System (INIS)

Fujii-e, Yoichi; Arie, Kazuo; Endo, Hiroshi

1992-01-01

A nuclear energy system should provide a stable supply of energy without endangering the environment or humans. If there is fear about exhausting world energy resources, accumulating radionuclides, and nuclear reactor safety, tension is created in human society. Nuclear energy systems of the future should be able to eliminate fear from people's minds. In other words, the whole system, including the nuclear fuel cycle, should be self-consistent. This is the ultimate goal of nuclear energy. If it can be realized, public acceptance of nuclear energy will increase significantly. In a self-consistent nuclear energy system, misunderstandings between experts on nuclear energy and the public should be minimized. The way to achieve this goal is to explain using simple logic. This paper proposes specific targets for self-consistent nuclear energy systems and shows that the fast breeder reactor (FBR) lies on the route to attaining the final goal

Column Chromatography To Obtain Organic Cation Sorption Isotherms.

Science.gov (United States)

Jolin, William C; Sullivan, James; Vasudevan, Dharni; MacKay, Allison A

2016-08-02

Column chromatography was evaluated as a method to obtain organic cation sorption isotherms for environmental solids while using the peak skewness to identify the linear range of the sorption isotherm. Custom packed HPLC columns and standard batch sorption techniques were used to intercompare sorption isotherms and solid-water sorption coefficients (Kd) for four organic cations (benzylamine, 2,4-dichlorobenzylamine, phenyltrimethylammonium, oxytetracycline) with two aluminosilicate clay minerals and one soil. A comparison of Freundlich isotherm parameters revealed isotherm linearity or nonlinearity was not significantly different between column chromatography and traditional batch experiments. Importantly, skewness (a metric of eluting peak symmetry) analysis of eluting peaks can establish isotherm linearity, thereby enabling a less labor intensive means to generate the extensive data sets of linear Kd values required for the development of predictive sorption models. Our findings clearly show that column chromatography can reproduce sorption measures from conventional batch experiments with the benefit of lower labor-intensity, faster analysis times, and allow for consistent sorption measures across laboratories with distinct chromatography instrumentation.

Functional analysis of Rift Valley fever virus NSs encoding a partial truncation.

Science.gov (United States)

Head, Jennifer A; Kalveram, Birte; Ikegami, Tetsuro

2012-01-01

Rift Valley fever virus (RVFV), belongs to genus Phlebovirus of the family Bunyaviridae, causes high rates of abortion and fetal malformation in infected ruminants as well as causing neurological disorders, blindness, or lethal hemorrhagic fever in humans. RVFV is classified as a category A priority pathogen and a select agent in the U.S., and currently there are no therapeutics available for RVF patients. NSs protein, a major virulence factor of RVFV, inhibits host transcription including interferon (IFN)-β mRNA synthesis and promotes degradation of dsRNA-dependent protein kinase (PKR). NSs self-associates at the C-terminus 17 aa., while NSs at aa.210-230 binds to Sin3A-associated protein (SAP30) to inhibit the activation of IFN-β promoter. Thus, we hypothesize that NSs function(s) can be abolished by truncation of specific domains, and co-expression of nonfunctional NSs with intact NSs will result in the attenuation of NSs function by dominant-negative effect. Unexpectedly, we found that RVFV NSs truncated at aa. 6-30, 31-55, 56-80, 81-105, 106-130, 131-155, 156-180, 181-205, 206-230, 231-248 or 249-265 lack functions of IFN-β mRNA synthesis inhibition and degradation of PKR. Truncated NSs were less stable in infected cells, while nuclear localization was inhibited in NSs lacking either of aa.81-105, 106-130, 131-155, 156-180, 181-205, 206-230 or 231-248. Furthermore, none of truncated NSs had exhibited significant dominant-negative functions for NSs-mediated IFN-β suppression or PKR degradation upon co-expression in cells infected with RVFV. We also found that any of truncated NSs except for intact NSs does not interact with RVFV NSs even in the presence of intact C-terminus self-association domain. Our results suggest that conformational integrity of NSs is important for the stability, cellular localization and biological functions of RVFV NSs, and the co-expression of truncated NSs does not exhibit dominant-negative phenotype.

Functional analysis of Rift Valley fever virus NSs encoding a partial truncation.

Directory of Open Access Journals (Sweden)

Jennifer A Head

Full Text Available Rift Valley fever virus (RVFV, belongs to genus Phlebovirus of the family Bunyaviridae, causes high rates of abortion and fetal malformation in infected ruminants as well as causing neurological disorders, blindness, or lethal hemorrhagic fever in humans. RVFV is classified as a category A priority pathogen and a select agent in the U.S., and currently there are no therapeutics available for RVF patients. NSs protein, a major virulence factor of RVFV, inhibits host transcription including interferon (IFN-β mRNA synthesis and promotes degradation of dsRNA-dependent protein kinase (PKR. NSs self-associates at the C-terminus 17 aa., while NSs at aa.210-230 binds to Sin3A-associated protein (SAP30 to inhibit the activation of IFN-β promoter. Thus, we hypothesize that NSs function(s can be abolished by truncation of specific domains, and co-expression of nonfunctional NSs with intact NSs will result in the attenuation of NSs function by dominant-negative effect. Unexpectedly, we found that RVFV NSs truncated at aa. 6-30, 31-55, 56-80, 81-105, 106-130, 131-155, 156-180, 181-205, 206-230, 231-248 or 249-265 lack functions of IFN-β mRNA synthesis inhibition and degradation of PKR. Truncated NSs were less stable in infected cells, while nuclear localization was inhibited in NSs lacking either of aa.81-105, 106-130, 131-155, 156-180, 181-205, 206-230 or 231-248. Furthermore, none of truncated NSs had exhibited significant dominant-negative functions for NSs-mediated IFN-β suppression or PKR degradation upon co-expression in cells infected with RVFV. We also found that any of truncated NSs except for intact NSs does not interact with RVFV NSs even in the presence of intact C-terminus self-association domain. Our results suggest that conformational integrity of NSs is important for the stability, cellular localization and biological functions of RVFV NSs, and the co-expression of truncated NSs does not exhibit dominant-negative phenotype.

STP: A mathematically and physically consistent library of steam properties

International Nuclear Information System (INIS)

Aguilar, F.; Hutter, A.C.; Tuttle, P.G.

1982-01-01

A new FORTRAN library of subroutines has been developed from the fundamental equation of Keenan et al. to evaluate a large set of water properties including derivatives such as sound speed and isothermal compressibility. The STP library uses the true saturation envelope of the Keenan et al. fundamental equation. The evaluation of the true envelope by a continuation method is explained. This envelope, along with other design features, imparts an exceptionally high degree of thermodynamic and mathematical consistency to the STP library, even at the critical point. Accuracy and smoothness, library self-consistency, and designed user convenience make the STP library a reliable and versatile water property package

Self-consistent descriptions of vector mesons in hot matter reexamined

International Nuclear Information System (INIS)

Riek, Felix; Knoll, Joern

2010-01-01

Technical concepts are presented that improve the self-consistent treatment of vector mesons in a hot and dense medium. First applications concern an interacting gas of pions and ρ mesons. As an extension of earlier studies, we thereby include random-phase-approximation-type vertex corrections and further use dispersion relations to calculate the real part of the vector-meson self-energy. An improved projection method preserves the four transversality of the vector-meson polarization tensor throughout the self-consistent calculations, thereby keeping the scheme void of kinematical singularities.

Approximate self-consistent potentials for density-functional-theory exchange-correlation functionals

International Nuclear Information System (INIS)

Cafiero, Mauricio; Gonzalez, Carlos

2005-01-01

We show that potentials for exchange-correlation functionals within the Kohn-Sham density-functional-theory framework may be written as potentials for simpler functionals multiplied by a factor close to unity, and in a self-consistent field calculation, these effective potentials find the correct self-consistent solutions. This simple theory is demonstrated with self-consistent exchange-only calculations of the atomization energies of some small molecules using the Perdew-Kurth-Zupan-Blaha (PKZB) meta-generalized-gradient-approximation (meta-GGA) exchange functional. The atomization energies obtained with our method agree with or surpass previous meta-GGA calculations performed in a non-self-consistent manner. The results of this work suggest the utility of this simple theory to approximate exchange-correlation potentials corresponding to energy functionals too complicated to generate closed forms for their potentials. We hope that this method will encourage the development of complex functionals which have correct boundary conditions and are free of self-interaction errors without the worry that the functionals are too complex to differentiate to obtain potentials

Self-consistent Bayesian analysis of space-time symmetry studies

International Nuclear Information System (INIS)

Davis, E.D.

1996-01-01

We introduce a Bayesian method for the analysis of epithermal neutron transmission data on space-time symmetries in which unique assignment of the prior is achieved by maximisation of the cross entropy and the imposition of a self-consistency criterion. Unlike the maximum likelihood method used in previous analyses of parity-violation data, our method is freed of an ad hoc cutoff parameter. Monte Carlo studies indicate that our self-consistent Bayesian analysis is superior to the maximum likelihood method when applied to the small data samples typical of symmetry studies. (orig.)

Self-consistent RPA based on a many-body vacuum

International Nuclear Information System (INIS)

Jemaï, M.; Schuck, P.

2011-01-01

Self-Consistent RPA is extended in a way so that it is compatible with a variational ansatz for the ground-state wave function as a fermionic many-body vacuum. Employing the usual equation-of-motion technique, we arrive at extended RPA equations of the Self-Consistent RPA structure. In principle the Pauli principle is, therefore, fully respected. However, the correlation functions entering the RPA matrix can only be obtained from a systematic expansion in powers of some combinations of RPA amplitudes. We demonstrate for a model case that this expansion may converge rapidly.

Consistency of the Self-Schema in Depression.

Science.gov (United States)

Ross, Michael J.; Mueller, John H.

Depressed individuals may filter or distort environmental information in direct relationship to their self perceptions. To investigate the degree of uncertainty about oneself and others, as measured by consistent/inconsistent responses, 72 college students (32 depressed and 40 nondepressed) rated selected adjectives from the Derry and Kuiper…

Self-consistent electron transport in collisional plasmas

International Nuclear Information System (INIS)

Mason, R.J.

1982-01-01

A self-consistent scheme has been developed to model electron transport in evolving plasmas of arbitrary classical collisionality. The electrons and ions are treated as either multiple donor-cell fluids, or collisional particles-in-cell. Particle suprathermal electrons scatter off ions, and drag against fluid background thermal electrons. The background electrons undergo ion friction, thermal coupling, and bremsstrahlung. The components move in self-consistent advanced E-fields, obtained by the Implicit Moment Method, which permits Δt >> ω/sub p/ -1 and Δx >> lambda/sub D/ - offering a 10 2 - 10 3 -fold speed-up over older explicit techniques. The fluid description for the background plasma components permits the modeling of transport in systems spanning more than a 10 7 -fold change in density, and encompassing contiguous collisional and collisionless regions. Results are presented from application of the scheme to the modeling of CO 2 laser-generated suprathermal electron transport in expanding thin foils, and in multi-foil target configurations

Self-consistent velocity dependent effective interactions

International Nuclear Information System (INIS)

Kubo, Takayuki; Sakamoto, Hideo; Kammuri, Tetsuo; Kishimoto, Teruo.

1993-09-01

The field coupling method is extended to a system with a velocity dependent mean potential. By means of this method, we can derive the effective interactions which are consistent with the mean potential. The self-consistent velocity dependent effective interactions are applied to the microscopic analysis of the structures of giant dipole resonances (GDR) of 148,154 Sm, of the first excited 2 + states of Sn isotopes and of the first excited 3 - states of Mo isotopes. It is clarified that the interactions play crucial roles in describing the splitting of the resonant structure of GDR peaks, in restoring the energy weighted sum rule values, and in reducing B (Eλ) values. (author)

Self-consistent nuclear energy systems

International Nuclear Information System (INIS)

Shimizu, A.; Fujiie, Y.

1995-01-01

A concept of self-consistent energy systems (SCNES) has been proposed as an ultimate goal of the nuclear energy system in the coming centuries. SCNES should realize a stable and unlimited energy supply without endangering the human race and the global environment. It is defined as a system that realizes at least the following four objectives simultaneously: (a) energy generation -attain high efficiency in the utilization of fission energy; (b) fuel production - secure inexhaustible energy source: breeding of fissile material with the breeding ratio greater than one and complete burning of transuranium through recycling; (c) burning of radionuclides - zero release of radionuclides from the system: complete burning of transuranium and elimination of radioactive fission products by neutron capture reactions through recycling; (d) system safety - achieve system safety both for the public and experts: eliminate criticality-related safety issues by using natural laws and simple logic. This paper describes the concept of SCNES and discusses the feasibility of the system. Both ''neutron balance'' and ''energbalance'' of the system are introduced as the necessary conditions to be satisfied at least by SCNES. Evaluations made so far indicate that both the neutron balance and the energy balance can be realized by fast reactors but not by thermal reactors. Concerning the system safety, two safety concepts: ''self controllability'' and ''self-terminability'' are introduced to eliminate the criticality-related safety issues in fast reactors. (author)

Self-consistent theory of a harmonic gyroklystron with a minimum Q cavity

International Nuclear Information System (INIS)

Tran, T.M.; Kreischer, K.E.; Temkin, R.J.

1986-01-01

In this paper, the energy extraction stage of the gyroklystron [in Advances in Electronics and Electron Physics, edited by C. Marton (Academic, New York, 1979), Vol. 1, pp. 1--54], with a minimum Q cavity is investigated by using a self-consistent radio-frequency (rf) field model. In the low-field, low-current limit, expressions for the self-consistent field and the resulting energy extraction efficiency are derived analytically for an arbitrary cyclotron harmonic number. To our knowledge, these are the first analytic results for the self-consistent field structure and efficiency of a gyrotron device. The large signal regime analysis is carried out by numerically integrating the coupled self-consistent equations. Several examples in this regime are presented

Multiple-scattering theory with a truncated basis set

International Nuclear Information System (INIS)

Zhang, X.; Butler, W.H.

1992-01-01

Multiple-scattering theory (MST) is an extremely efficient technique for calculating the electronic structure of an assembly of atoms. The wave function in MST is expanded in terms of spherical waves centered on each atom and indexed by their orbital and azimuthal quantum numbers, l and m. The secular equation which determines the characteristic energies can be truncated at a value of the orbital angular momentum l max , for which the higher angular momentum phase shifts, δ l (l>l max ), are sufficiently small. Generally, the wave-function coefficients which are calculated from the secular equation are also truncated at l max . Here we point out that this truncation of the wave function is not necessary and is in fact inconsistent with the truncation of the secular equation. A consistent procedure is described in which the states with higher orbital angular momenta are retained but with their phase shifts set to zero. We show that this treatment gives smooth, continuous, and correctly normalized wave functions and that the total charge density calculated from the corresponding Green function agrees with the Lloyd formula result. We also show that this augmented wave function can be written as a linear combination of Andersen's muffin-tin orbitals in the case of muffin-tin potentials, and can be used to generalize the muffin-tin orbital idea to full-cell potentals

Fully self-consistent GW calculations for molecules

DEFF Research Database (Denmark)

Rostgaard, Carsten; Jacobsen, Karsten Wedel; Thygesen, Kristian Sommer

2010-01-01

We calculate single-particle excitation energies for a series of 34 molecules using fully self-consistent GW, one-shot G0W0, Hartree-Fock (HF), and hybrid density-functional theory (DFT). All calculations are performed within the projector-augmented wave method using a basis set of Wannier...... functions augmented by numerical atomic orbitals. The GW self-energy is calculated on the real frequency axis including its full frequency dependence and off-diagonal matrix elements. The mean absolute error of the ionization potential (IP) with respect to experiment is found to be 4.4, 2.6, 0.8, 0.4, and 0...

Self-consistent description of the isospin mixing

International Nuclear Information System (INIS)

Gabrakov, S.I.; Pyatov, N.I.; Baznat, M.I.; Salamov, D.I.

1978-03-01

The properties of collective 0 + states built of unlike particle-hole excitations in spherical nuclei have been investigated in a self-consistent microscopic approach. These states arise when the broken isospin symmetry of the nuclear shell model Hamiltonian is restored. The numerical calculations were performed with Woods-Saxon wave functions

Oscillations of non-isothermal N/S boundary with a high frequency and large amplitude

International Nuclear Information System (INIS)

Bezuglyj, A.I.; Shklovskij, V.A.

2016-01-01

Within the framework of the phenomenological approach based on the heat balance equation and the dependence of the critical temperature of the superconductor on the current value theoretically investigated the impact of high-frequency current of high amplitude and arbitrary shape on the non-isothermal balance of the oscillating N/S interface in a long superconductor. We introduce a self-consistent average temperature field of rapidly oscillating non-isothermal N/S boundary (heat kink), which allows to go beyond the well-known concept of mean-square heating and consider the impact of current waveform. With regard to experiments on the effects of microwave high-power radiation on the current-voltage characteristics (CVC) of superconducting films, we give the classification of the families of the CVC for inhomogeneous superconductors which carry a current containing a high frequency component of large amplitude. Several characteristics have hysteresis of thermal nature.

Nonstatic, self-consistent πN t matrix in nuclear matter

International Nuclear Information System (INIS)

Van Orden, J.W.

1984-01-01

In a recent paper, a calculation of the self-consistent πN t matrix in nuclear matter was presented. In this calculation the driving term of the self-consistent equation was chosen to be a static approximation to the free πN t matrix. In the present work, the earlier calculation is extended by using a nonstatic, fully-off-shell free πN t matrix as a starting point. Right-hand pole and cut contributions to the P-wave πN amplitudes are derived using a Low expansion and include effects due to recoil of the interacting πN system as well as the transformation from the πN c.m. frame to the nuclear rest frame. The self-consistent t-matrix equation is rewritten as two integral equations which modify the pole and cut contributions to the t matrix separately. The self-consistent πN t matrix is calculated in nuclear matter and a nonlocal optical potential is constructed from it. The resonant contribution to the optical potential is found to be broadened by 20% to 50% depending on pion momentum and is shifted upward in energy by approximately 10 MeV in comparison to the first-order optical potential. Modifications to the nucleon pole contribution are found to be negligible

No chiral truncation of quantum log gravity?

Science.gov (United States)

Andrade, Tomás; Marolf, Donald

2010-03-01

At the classical level, chiral gravity may be constructed as a consistent truncation of a larger theory called log gravity by requiring that left-moving charges vanish. In turn, log gravity is the limit of topologically massive gravity (TMG) at a special value of the coupling (the chiral point). We study the situation at the level of linearized quantum fields, focussing on a unitary quantization. While the TMG Hilbert space is continuous at the chiral point, the left-moving Virasoro generators become ill-defined and cannot be used to define a chiral truncation. In a sense, the left-moving asymptotic symmetries are spontaneously broken at the chiral point. In contrast, in a non-unitary quantization of TMG, both the Hilbert space and charges are continuous at the chiral point and define a unitary theory of chiral gravity at the linearized level.

Truncated Groebner fans and lattice ideals

OpenAIRE

Lauritzen, Niels

2005-01-01

We outline a generalization of the Groebner fan of a homogeneous ideal with maximal cells parametrizing truncated Groebner bases. This "truncated" Groebner fan is usually much smaller than the full Groebner fan and offers the natural framework for conversion between truncated Groebner bases. The generic Groebner walk generalizes naturally to this setting by using the Buchberger algorithm with truncation on facets. We specialize to the setting of lattice ideals. Here facets along the generic w...

Thermodynamically self-consistent integral equations and the structure of liquid metals

International Nuclear Information System (INIS)

Pastore, G.; Kahl, G.

1987-01-01

We discuss the application of the new thermodynamically self-consistent integral equations for the determination of the structural properties of liquid metals. We present a detailed comparison of the structure (S(q) and g(r)) for models of liquid alkali metals as obtained from two thermodynamically self-consistent integral equations and some published exact computer simulation results; the range of states extends from the triple point to the expanded metal. The theories which only impose thermodynamic self-consistency without any fitting of external data show an excellent agreement with the simulation results, thus demonstrating that this new type of integral equation is definitely superior to the conventional ones (hypernetted chain, Percus-Yevick, mean spherical approximation, etc). (author)

Self-consistent tight-binding model of B and N doping in graphene

DEFF Research Database (Denmark)

Pedersen, Thomas Garm; Pedersen, Jesper Goor

2013-01-01

. The impurity potential depends sensitively on the impurity occupancy, leading to a self-consistency requirement. We solve this problem using the impurity Green's function and determine the self-consistent local density of states at the impurity site and, thereby, identify acceptor and donor energy resonances.......Boron and nitrogen substitutional impurities in graphene are analyzed using a self-consistent tight-binding approach. An analytical result for the impurity Green's function is derived taking broken electron-hole symmetry into account and validated by comparison to numerical diagonalization...

Statistical estimation for truncated exponential families

CERN Document Server

Akahira, Masafumi

2017-01-01

This book presents new findings on nonregular statistical estimation. Unlike other books on this topic, its major emphasis is on helping readers understand the meaning and implications of both regularity and irregularity through a certain family of distributions. In particular, it focuses on a truncated exponential family of distributions with a natural parameter and truncation parameter as a typical nonregular family. This focus includes the (truncated) Pareto distribution, which is widely used in various fields such as finance, physics, hydrology, geology, astronomy, and other disciplines. The family is essential in that it links both regular and nonregular distributions, as it becomes a regular exponential family if the truncation parameter is known. The emphasis is on presenting new results on the maximum likelihood estimation of a natural parameter or truncation parameter if one of them is a nuisance parameter. In order to obtain more information on the truncation, the Bayesian approach is also considere...

NLO renormalization in the Hamiltonian truncation

Science.gov (United States)

Elias-Miró, Joan; Rychkov, Slava; Vitale, Lorenzo G.

2017-09-01

Hamiltonian truncation (also known as "truncated spectrum approach") is a numerical technique for solving strongly coupled quantum field theories, in which the full Hilbert space is truncated to a finite-dimensional low-energy subspace. The accuracy of the method is limited only by the available computational resources. The renormalization program improves the accuracy by carefully integrating out the high-energy states, instead of truncating them away. In this paper, we develop the most accurate ever variant of Hamiltonian Truncation, which implements renormalization at the cubic order in the interaction strength. The novel idea is to interpret the renormalization procedure as a result of integrating out exactly a certain class of high-energy "tail states." We demonstrate the power of the method with high-accuracy computations in the strongly coupled two-dimensional quartic scalar theory and benchmark it against other existing approaches. Our work will also be useful for the future goal of extending Hamiltonian truncation to higher spacetime dimensions.

Vibrational multiconfiguration self-consistent field theory: implementation and test calculations.

Science.gov (United States)

Heislbetz, Sandra; Rauhut, Guntram

2010-03-28

A state-specific vibrational multiconfiguration self-consistent field (VMCSCF) approach based on a multimode expansion of the potential energy surface is presented for the accurate calculation of anharmonic vibrational spectra. As a special case of this general approach vibrational complete active space self-consistent field calculations will be discussed. The latter method shows better convergence than the general VMCSCF approach and must be considered the preferred choice within the multiconfigurational framework. Benchmark calculations are provided for a small set of test molecules.

Multiplicative renormalizability and self-consistent treatments of the Schwinger-Dyson equations

International Nuclear Information System (INIS)

Brown, N.; Dorey, N.

1989-11-01

Many approximations to the Schwinger-Dyson equations place constraints on the renormalization constants of a theory. The requirement that the solutions to the equations be multiplicatively renormalizable also places constraints on these constants. Demanding that these two sets of constraints be compatible is an important test of the self-consistency of the approximations made. We illustrate this idea by considering the equation for the fermion propagator in massless quenched quantum electrodynamics, (QED), checking the consistency of various approximations. In particular, we show that the much used 'ladder' approximation is self-consistent, provided that the coupling constant is renormalized in a particular way. We also propose another approximation which satisfies this self-consistency test, but requires that the coupling be unrenormalized, as should be the case in the full quenched approximation. This new approximation admits an exact solution, which also satisfies the renormalization group equation for the quenched approximation. (author)

Stability of Slopes Reinforced with Truncated Piles

Directory of Open Access Journals (Sweden)

Shu-Wei Sun

2016-01-01

Full Text Available Piles are extensively used as a means of slope stabilization. A novel engineering technique of truncated piles that are unlike traditional piles is introduced in this paper. A simplified numerical method is proposed to analyze the stability of slopes stabilized with truncated piles based on the shear strength reduction method. The influential factors, which include pile diameter, pile spacing, depth of truncation, and existence of a weak layer, are systematically investigated from a practical point of view. The results show that an optimum ratio exists between the depth of truncation and the pile length above a slip surface, below which truncating behavior has no influence on the piled slope stability. This optimum ratio is bigger for slopes stabilized with more flexible piles and piles with larger spacing. Besides, truncated piles are more suitable for slopes with a thin weak layer than homogenous slopes. In practical engineering, the piles could be truncated reasonably while ensuring the reinforcement effect. The truncated part of piles can be filled with the surrounding soil and compacted to reduce costs by using fewer materials.

Flow equation of quantum Einstein gravity in a higher-derivative truncation

International Nuclear Information System (INIS)

Lauscher, O.; Reuter, M.

2002-01-01

Motivated by recent evidence indicating that quantum Einstein gravity (QEG) might be nonperturbatively renormalizable, the exact renormalization group equation of QEG is evaluated in a truncation of theory space which generalizes the Einstein-Hilbert truncation by the inclusion of a higher-derivative term (R 2 ). The beta functions describing the renormalization group flow of the cosmological constant, Newton's constant, and the R 2 coupling are computed explicitly. The fixed point properties of the 3-dimensional flow are investigated, and they are confronted with those of the 2-dimensional Einstein-Hilbert flow. The non-Gaussian fixed point predicted by the latter is found to generalize to a fixed point on the enlarged theory space. In order to test the reliability of the R 2 truncation near this fixed point we analyze the residual scheme dependence of various universal quantities; it turns out to be very weak. The two truncations are compared in detail, and their numerical predictions are found to agree with a surprisingly high precision. Because of the consistency of the results it appears increasingly unlikely that the non-Gaussian fixed point is an artifact of the truncation. If it is present in the exact theory QEG is probably nonperturbatively renormalizable and ''asymptotically safe.'' We discuss how the conformal factor problem of Euclidean gravity manifests itself in the exact renormalization group approach and show that, in the R 2 truncation, the investigation of the fixed point is not afflicted with this problem. Also the Gaussian fixed point of the Einstein-Hilbert truncation is analyzed; it turns out that it does not generalize to a corresponding fixed point on the enlarged theory space

Self-consistent cluster theory for systems with off-diagonal disorder

International Nuclear Information System (INIS)

Kaplan, T.; Leath, P.L.; Gray, L.J.; Diehl, H.W.

1980-01-01

A self-consistent cluster theory for elementary excitations in systems with diagonal, off-diagonal, and environmental disorder is presented. The theory is developed in augmented space where the configurational average over the disorder is replaced by a ground-state matrix element in a translationally invariant system. The analyticity of the resulting approximate Green's function is proved. Numerical results for the self-consistent single-site and pair approximations are presented for the vibrational and electronic properties of disordered linear chains with diagonal, off-diagonal, and environmental disorder

MultiSIMNRA: A computational tool for self-consistent ion beam analysis using SIMNRA

International Nuclear Information System (INIS)

Silva, T.F.; Rodrigues, C.L.; Mayer, M.; Moro, M.V.; Trindade, G.F.; Aguirre, F.R.; Added, N.; Rizzutto, M.A.; Tabacniks, M.H.

2016-01-01

Highlights: • MultiSIMNRA enables the self-consistent analysis of multiple ion beam techniques. • Self-consistent analysis enables unequivocal and reliable modeling of the sample. • Four different computational algorithms available for model optimizations. • Definition of constraints enables to include prior knowledge into the analysis. - Abstract: SIMNRA is widely adopted by the scientific community of ion beam analysis for the simulation and interpretation of nuclear scattering techniques for material characterization. Taking advantage of its recognized reliability and quality of the simulations, we developed a computer program that uses multiple parallel sessions of SIMNRA to perform self-consistent analysis of data obtained by different ion beam techniques or in different experimental conditions of a given sample. In this paper, we present a result using MultiSIMNRA for a self-consistent multi-elemental analysis of a thin film produced by magnetron sputtering. The results demonstrate the potentialities of the self-consistent analysis and its feasibility using MultiSIMNRA.

Self-consistent T-matrix theory of superconductivity

Czech Academy of Sciences Publication Activity Database

Šopík, B.; Lipavský, Pavel; Männel, M.; Morawetz, K.; Matlock, P.

2011-01-01

Roč. 84, č. 9 (2011), 094529/1-094529/13 ISSN 1098-0121 R&D Projects: GA ČR GAP204/10/0212; GA ČR(CZ) GAP204/11/0015 Institutional research plan: CEZ:AV0Z10100521 Keywords : superconductivity * T-matrix * superconducting gap * restricted self-consistency Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.691, year: 2011

Self-consistent modelling of ICRH

International Nuclear Information System (INIS)

Hellsten, T.; Hedin, J.; Johnson, T.; Laxaaback, M.; Tennfors, E.

2001-01-01

The performance of ICRH is often sensitive to the shape of the high energy part of the distribution functions of the resonating species. This requires self-consistent calculations of the distribution functions and the wave-field. In addition to the wave-particle interactions and Coulomb collisions the effects of the finite orbit width and the RF-induced spatial transport are found to be important. The inward drift dominates in general even for a symmetric toroidal wave spectrum in the centre of the plasma. An inward drift does not necessarily produce a more peaked heating profile. On the contrary, for low concentrations of hydrogen minority in deuterium plasmas it can even give rise to broader profiles. (author)

Quantitative verification of ab initio self-consistent laser theory.

Science.gov (United States)

Ge, Li; Tandy, Robert J; Stone, A D; Türeci, Hakan E

2008-10-13

We generalize and test the recent "ab initio" self-consistent (AISC) time-independent semiclassical laser theory. This self-consistent formalism generates all the stationary lasing properties in the multimode regime (frequencies, thresholds, internal and external fields, output power and emission pattern) from simple inputs: the dielectric function of the passive cavity, the atomic transition frequency, and the transverse relaxation time of the lasing transition.We find that the theory gives excellent quantitative agreement with full time-dependent simulations of the Maxwell-Bloch equations after it has been generalized to drop the slowly-varying envelope approximation. The theory is infinite order in the non-linear hole-burning interaction; the widely used third order approximation is shown to fail badly.

Real-time electrochemical monitoring of isothermal helicase-dependent amplification of nucleic acids.

Science.gov (United States)

Kivlehan, Francine; Mavré, François; Talini, Luc; Limoges, Benoît; Marchal, Damien

2011-09-21

We described an electrochemical method to monitor in real-time the isothermal helicase-dependent amplification of nucleic acids. The principle of detection is simple and well-adapted to the development of portable, easy-to-use and inexpensive nucleic acids detection technologies. It consists of monitoring a decrease in the electrochemical current response of a reporter DNA intercalating redox probe during the isothermal DNA amplification. The method offers the possibility to quantitatively analyze target nucleic acids in less than one hour at a single constant temperature, and to perform at the end of the isothermal amplification a DNA melt curve analysis for differentiating between specific and non-specific amplifications. To illustrate the potentialities of this approach for the development of a simple, robust and low-cost instrument with high throughput capability, the method was validated with an electrochemical system capable of monitoring up to 48 real-time isothermal HDA reactions simultaneously in a disposable microplate consisting of 48-electrochemical microwells. Results obtained with this approach are comparable to that obtained with a well-established but more sophisticated and expensive fluorescence-based method. This makes for a promising alternative detection method not only for real-time isothermal helicase-dependent amplification of nucleic acid, but also for other isothermal DNA amplification strategies.

Nonequilibrium steady state of biochemical cycle kinetics under non-isothermal conditions

Science.gov (United States)

Jin, Xiao; Ge, Hao

2018-04-01

The nonequilibrium steady state of isothermal biochemical cycle kinetics has been extensively studied, but that under non-isothermal conditions has been much less extensively investigated. When the heat exchange between subsystems is slow, the isothermal assumption of the whole system breaks down, as is true for many types of living organisms. Here, starting with a four-state model of molecular transporter across the cell membrane, we generalize the nonequilibrium steady-state theory of isothermal biochemical cycle kinetics to the circumstances with non-uniform temperatures of subsystems in terms of general master equation models. We obtain a new thermodynamic relationship between the chemical reaction rates and thermodynamic potentials in non-isothermal circumstances, based on the overdamped dynamics along the continuous reaction coordinate. We show that the entropy production can vary up to 3% in real cells, even when the temperature difference across the cell membrane is only approximately 1 K. We then decompose the total thermodynamic driving force into its thermal and chemical components and predict that the net flux of molecules transported by the molecular transporter can potentially go against the temperature gradient in the absence of a chemical driving force. Furthermore, we demonstrate that the simple application of the isothermal transition-state rate formula for each chemical reaction in terms of only the reactant’ temperature is not thermodynamically consistent. Therefore, we mathematically derive several revised reaction rate formulas that are not only consistent with the new thermodynamic relationship but also approximate the exact reaction rate better than Kramers’ rate formula under isothermal conditions.

Renormalization of self-consistent Schwinger-Dyson equations at finite temperature

International Nuclear Information System (INIS)

Hees, H. van; Knoll, J.

2002-01-01

We show that Dyson resummation schemes based on Baym's Φ-derivable approximations can be renormalized with counter term structures solely defined on the vacuum level. First applications to the self-consistent solution of the sunset self-energy in φ 4 -theory are presented. (orig.)

A SUZAKU OBSERVATION OF NGC 4593: ILLUMINATING THE TRUNCATED DISK

International Nuclear Information System (INIS)

Markowitz, A. G.; Reeves, J. N.

2009-01-01

We report results from a 2007 Suzaku observation of the Seyfert 1 AGN NGC 4593. The narrow Fe Kα emission line has a FWHM width ∼ 4000 km s -1 , indicating emission from ∼> 5000 R g . There is no evidence for a relativistically broadened Fe K line, consistent with the presence of a radiatively efficient outer disk which is truncated or transitions to an interior radiatively inefficient flow. The Suzaku observation caught the source in a low-flux state; comparison to a 2002 XMM-Newton observation indicates that the hard X-ray flux decreased by 3.6, while the Fe Kα line intensity and width σ each roughly halved. Two model-dependent explanations for the changes in Fe Kα line profile are explored. In one, the Fe Kα line width has decreased from ∼10,000 to ∼4000 km s -1 from 2002 to 2007, suggesting that the thin disk truncation/transition radius has increased from 1000-2000 to ∼>5000 R g . However, there are indications from other compact accreting systems that such truncation radii tend to be associated only with accretion rates relative to Eddington much lower than that of NGC 4593. In the second model, the line profile in the XMM-Newton observation consists of a time-invariant narrow component plus a broad component originating from the inner part of the truncated disk (∼300 R g ) which has responded to the drop in continuum flux. The Compton reflection component strength R is ∼ 1.1, consistent with the measured Fe Kα line total equivalent width with an Fe abundance 1.7 times the solar value. The modest soft excess, modeled well by either thermal bremsstrahlung emission or by Comptonization of soft seed photons in an optical thin plasma, has fallen by a factor of ∼20 from 2002 to 2007, ruling out emission from a region 5 lt-yr in size.

Self-consistent Green’s-function technique for surfaces and interfaces

DEFF Research Database (Denmark)

Skriver, Hans Lomholt; Rosengaard, N. M.

1991-01-01

We have implemented an efficient self-consistent Green’s-function technique for calculating ground-state properties of surfaces and interfaces, based on the linear-muffin-tin-orbitals method within the tight-binding representation. In this approach the interlayer interaction is extremely short...... ranged, and only a few layers close to the interface need be treated self-consistently via a Dyson equation. For semi-infinite jellium, the technique gives work functions and surface energies that are in excellent agreement with earlier calculations. For the bcc(110) surface of the alkali metals, we find...

Computing correct truncated excited state wavefunctions

Science.gov (United States)

Bacalis, N. C.; Xiong, Z.; Zang, J.; Karaoulanis, D.

2016-12-01

We demonstrate that, if a wave function's truncated expansion is small, then the standard excited states computational method, of optimizing one "root" of a secular equation, may lead to an incorrect wave function - despite the correct energy according to the theorem of Hylleraas, Undheim and McDonald - whereas our proposed method [J. Comput. Meth. Sci. Eng. 8, 277 (2008)] (independent of orthogonality to lower lying approximants) leads to correct reliable small truncated wave functions. The demonstration is done in He excited states, using truncated series expansions in Hylleraas coordinates, as well as standard configuration-interaction truncated expansions.

Autocorrelation as a source of truncated Lévy flights in foreign exchange rates

Science.gov (United States)

Figueiredo, Annibal; Gleria, Iram; Matsushita, Raul; Da Silva, Sergio

2003-05-01

We suggest that the ultraslow speed of convergence associated with truncated Lévy flights (Phys. Rev. Lett. 73 (1994) 2946) may well be explained by autocorrelations in data. We show how a particular type of autocorrelation generates power laws consistent with a truncated Lévy flight. Stock exchanges have been suggested to be modeled by a truncated Lévy flight (Nature 376 (1995) 46; Physica A 297 (2001) 509; Econom. Bull. 7 (2002) 1). Here foreign exchange rate data are taken instead. Scaling power laws in the “probability of return to the origin” are shown to emerge for most currencies. A novel approach to measure how distant a process is from a Gaussian regime is presented.

Similarities between Prescott Lecky's theory of self-consistency and Carl Rogers' self-theory.

Science.gov (United States)

Merenda, Peter F

2010-10-01

The teachings of Prescott Lecky on the self-concept at Columbia University in the 1920s and 1930s and the posthumous publications of his book on self-consistency beginning in 1945 are compared with the many publications of Carl Rogers on the self-concept beginning in the early 1940s. Given that Rogers was a graduate student at Columbia in the 1920s and 1930s, the striking similarities between these two theorists, as well as claims attributed to Rogers by Rogers' biographers and writers who have quoted Rogers on his works relating to self-theory, strongly suggest that Rogers borrowed from Lecky without giving him the proper credit. Much of Rogers' writings on the self-concept included not only terms and concepts which were original with Lecky, but at times these were actually identical.

Self-consistent simulation of the CSR effect

International Nuclear Information System (INIS)

Li, R.; Bohn, C.L.; Bisogano, J.J.

1998-01-01

When a microbunch with high charge traverses a curved trajectory, the curvature-induced bunch self-interaction, by way of coherent synchrotron radiation (CSR) and space-charge forces, may cause serious emittance degradation. In this paper, the authors present a self-consistent simulation for the study of the impact of CSR on beam optics. The dynamics of the bunch under the influence of the CSR forces is simulated using macroparticles, where the CSR force in turn depends on the history of bunch dynamics in accordance with causality. The simulation is benchmarked with analytical results obtained for a rigid-line bunch. Here they present the algorithm used in the simulation, along with the simulation results obtained for bending systems in the Jefferson Lab (JLab) free-electron-laser (FEL) lattice

Two new integrable couplings of the soliton hierarchies with self-consistent sources

International Nuclear Information System (INIS)

Tie-Cheng, Xia

2010-01-01

A kind of integrable coupling of soliton equations hierarchy with self-consistent sources associated with s-tilde l(4) has been presented (Yu F J and Li L 2009 Appl. Math. Comput. 207 171; Yu F J 2008 Phys. Lett. A 372 6613). Based on this method, we construct two integrable couplings of the soliton hierarchy with self-consistent sources by using the loop algebra s-tilde l(4). In this paper, we also point out that there are some errors in these references and we have corrected these errors and set up new formula. The method can be generalized to other soliton hierarchy with self-consistent sources. (general)

Density Functional Theory and the Basis Set Truncation Problem with Correlation Consistent Basis Sets: Elephant in the Room or Mouse in the Closet?

Science.gov (United States)

Feller, David; Dixon, David A

2018-03-08

Two recent papers in this journal called into question the suitability of the correlation consistent basis sets for density functional theory (DFT) calculations, because the sets were designed for correlated methods such as configuration interaction, perturbation theory, and coupled cluster theory. These papers focused on the ability of the correlation consistent and other basis sets to reproduce total energies, atomization energies, and dipole moments obtained from "quasi-exact" multiwavelet results. Undesirably large errors were observed for the correlation consistent basis sets. One of the papers argued that basis sets specifically optimized for DFT methods were "essential" for obtaining high accuracy. In this work we re-examined the performance of the correlation consistent basis sets by resolving problems with the previous calculations and by making more appropriate basis set choices for the alkali and alkaline-earth metals and second-row elements. When this is done, the statistical errors with respect to the benchmark values and with respect to DFT optimized basis sets are greatly reduced, especially in light of the relatively large intrinsic error of the underlying DFT method. When judged with respect to high-quality Feller-Peterson-Dixon coupled cluster theory atomization energies, the PBE0 DFT method used in the previous studies exhibits a mean absolute deviation more than a factor of 50 larger than the quintuple zeta basis set truncation error.

Mixtures of truncated basis functions

DEFF Research Database (Denmark)

Langseth, Helge; Nielsen, Thomas Dyhre; Rumí, Rafael

2012-01-01

In this paper we propose a framework, called mixtures of truncated basis functions (MoTBFs), for representing general hybrid Bayesian networks. The proposed framework generalizes both the mixture of truncated exponentials (MTEs) framework and the mixture of polynomials (MoPs) framework. Similar t...

Applications of Fast Truncated Multiplication in Cryptography

Directory of Open Access Journals (Sweden)

Laszlo Hars

2006-12-01

Full Text Available Truncated multiplications compute truncated products, contiguous subsequences of the digits of integer products. For an n-digit multiplication algorithm of time complexity O(nα, with 1<α≤2, there is a truncated multiplication algorithm, which is constant times faster when computing a short enough truncated product. Applying these fast truncated multiplications, several cryptographic long integer arithmetic algorithms are improved, including integer reciprocals, divisions, Barrett and Montgomery multiplications, 2n-digit modular multiplication on hardware for n-digit half products. For example, Montgomery multiplication is performed in 2.6 Karatsuba multiplication time.

Analysis of a self-propelling sheet with heat transfer through non-isothermal fluid in an inclined human cervical canal.

Science.gov (United States)

Walait, Ahsan; Siddiqui, A M; Rana, M A

2018-02-13

The present theoretical analysis deals with biomechanics of the self-propulsion of a swimming sheet with heat transfer through non-isothermal fluid filling an inclined human cervical canal. Partial differential equations arising from the mathematical modeling of the proposed model are solved analytically. Flow variables like pressure gradient, propulsive velocity, fluid velocity, time mean flow rate, fluid temperature, and heat-transfer coefficients are analyzed for the pertinent parameters. Striking features of the pumping characteristics are explored. Propulsive velocity of the swimming sheet becomes faster for lower Froude number, higher Reynolds number, and for a vertical channel. Temperature and peak value of the heat-transfer coefficients below the swimming sheet showed an increase by the increment of Brinkmann number, inclination, pressure difference over wavelength, and Reynolds number whereas these quantities decrease with increasing Froude number. Aforesaid parameters have shown opposite effects on the peak value of the heat-transfer coefficients below and above the swimming sheet. Relevance of the current results to the spermatozoa transport with heat transfer through non-isothermal cervical mucus filling an inclined human cervical canal is also explored.

Isothermality of the gas in the Coma cluster

International Nuclear Information System (INIS)

Hughes, J.P.; Yamashita, K.; Okumura, Y.; Tsunemi, H.; Matsuoka, M.

1988-01-01

The high-quality X-ray spectrum of the Coma cluster observed by the Japanese satelite Tenma in conjunction with imaging data from the Einstein Observatory was used to explore the temperature distribution of the cluster gas. It is found that pure polytropic models are inadequate to describe this temperature distribution. Instead, a hybrid model is proposed consisting of a central isothermal region surrounded by a polytropic distribution. It is shown that as much as 75 percent of the global emission may come from the isothermal component. 30 references

Self-consistent calculation of steady-state creep and growth in textured zirconium

International Nuclear Information System (INIS)

Tome, C.N.; So, C.B.; Woo, C.H.

1993-01-01

Irradiation creep and growth in zirconium alloys result in anisotropic dimensional changes relative to the crystallographic axis in each individual grain. Several methods have been attempted to model such dimensional changes, taking into account the development of intergranular stresses. In this paper, we compare the predictions of several such models, namely the upper-bound, the lower-bound, the isotropic K* self-consistent (analytical) and the fully self-consistent (numerical) models. For given single-crystal creep compliances and growth factors, the polycrystal compliances predicted by the upper- and lower-bound models are unreliable. The predictions of the two self-consistent approaches are usually similar. The analytical isotropic K* approach is simple to implement and can be used to estimate the creep and growth rates of the polycrystal in many cases. The numerical fully self-consistent approach should be used when an accurate prediction of polycrystal creep is required, particularly for the important case of a closed-end internally pressurized tube. In most cases, the variations in grain shape introduce only minor corrections to the behaviour of polycrystalline materials. (author)

Energy transfer in compressible magnetohydrodynamic turbulence for isothermal self-gravitating fluids

Science.gov (United States)

Banerjee, Supratik; Kritsuk, Alexei G.

2018-02-01

Three-dimensional, compressible, magnetohydrodynamic turbulence of an isothermal, self-gravitating fluid is analyzed using two-point statistics in the asymptotic limit of large Reynolds numbers (both kinetic and magnetic). Following an alternative formulation proposed by Banerjee and Galtier [Phys. Rev. E 93, 033120 (2016), 10.1103/PhysRevE.93.033120; J. Phys. A: Math. Theor. 50, 015501 (2017), 10.1088/1751-8113/50/1/015501], an exact relation has been derived for the total energy transfer. This approach results in a simpler relation expressed entirely in terms of mixed second-order structure functions. The kinetic, thermodynamic, magnetic, and gravitational contributions to the energy transfer rate can be easily separated in the present form. By construction, the new formalism includes such additional effects as global rotation, the Hall term in the induction equation, etc. The analysis shows that solid-body rotation cannot alter the energy flux rate of compressible turbulence. However, the contribution of a uniform background magnetic field to the flux is shown to be nontrivial unlike in the incompressible case. Finally, the compressible, turbulent energy flux rate does not vanish completely due to simple alignments, which leads to a zero turbulent energy flux rate in the incompressible case.

Properties of truncated multiplicity distributions

International Nuclear Information System (INIS)

Lupia, S.

1995-01-01

Truncation effects on multiplicity distributions are discussed. Observables sensitive to the tail, like factorial moments, factorial cumulants and their ratio, are shown to be strongly affected by truncation. A possible way to overcome this problem by looking at the head of the distribution is suggested. (author)

Properties of truncated multiplicity distributions

Energy Technology Data Exchange (ETDEWEB)

Lupia, S. [Turin Univ. (Italy). Dipt. di Fisica

1995-12-31

Truncation effects on multiplicity distributions are discussed. Observables sensitive to the tail, like factorial moments, factorial cumulants and their ratio, are shown to be strongly affected by truncation. A possible way to overcome this problem by looking at the head of the distribution is suggested. (author)

Lamp with a truncated reflector cup

Science.gov (United States)

Li, Ming; Allen, Steven C.; Bazydola, Sarah; Ghiu, Camil-Daniel

2013-10-15

A lamp assembly, and method for making same. The lamp assembly includes first and second truncated reflector cups. The lamp assembly also includes at least one base plate disposed between the first and second truncated reflector cups, and a light engine disposed on a top surface of the at least one base plate. The light engine is configured to emit light to be reflected by one of the first and second truncated reflector cups.

Relativistic four-component multiconfigurational self-consistent-field theory for molecules

DEFF Research Database (Denmark)

Jensen, Hans Jørgen Aa; Dyall, Kenneth G.; Saue, Trond

1996-01-01

A formalism for relativistic four-component multiconfigurational self-consistent-field calculations on molecules is presented. The formalism parallels a direct second-order restricted-step algorithm developed for nonrelativistic molecular calculations. The presentation here focuses on the differe......A formalism for relativistic four-component multiconfigurational self-consistent-field calculations on molecules is presented. The formalism parallels a direct second-order restricted-step algorithm developed for nonrelativistic molecular calculations. The presentation here focuses...... the memory used by the largest nonrelativistic calculation in the equivalent basis, due to the complex arithmetic. The feasibility of the calculations is then determined more by the disk space for storage of integrals and N-particle expansion vectors....

Formal truncations of connected kernel equations

International Nuclear Information System (INIS)

Dixon, R.M.

1977-01-01

The Connected Kernel Equations (CKE) of Alt, Grassberger and Sandhas (AGS); Kouri, Levin and Tobocman (KLT); and Bencze, Redish and Sloan (BRS) are compared against reaction theory criteria after formal channel space and/or operator truncations have been introduced. The Channel Coupling Class concept is used to study the structure of these CKE's. The related wave function formalism of Sandhas, of L'Huillier, Redish and Tandy and of Kouri, Krueger and Levin are also presented. New N-body connected kernel equations which are generalizations of the Lovelace three-body equations are derived. A method for systematically constructing fewer body models from the N-body BRS and generalized Lovelace (GL) equations is developed. The formally truncated AGS, BRS, KLT and GL equations are analyzed by employing the criteria of reciprocity and two-cluster unitarity. Reciprocity considerations suggest that formal truncations of BRS, KLT and GL equations can lead to reciprocity-violating results. This study suggests that atomic problems should employ three-cluster connected truncations and that the two-cluster connected truncations should be a useful starting point for nuclear systems

Analytical relativistic self-consistent-field calculations for atoms

International Nuclear Information System (INIS)

Barthelat, J.C.; Pelissier, M.; Durand, P.

1980-01-01

A new second-order representation of the Dirac equation is presented. This representation which is exact for a hydrogen atom is applied to approximate analytical self-consistent-field calculations for atoms. Results are given for the rare-gas atoms from helium to radon and for lead. The results compare favorably with numerical Dirac-Hartree-Fock solutions

Towards a realization of the condensed-matter-gravity correspondence in string theory via consistent Abelian truncation of the Aharony-Bergman-Jafferis-Maldacena model.

Science.gov (United States)

Mohammed, Asadig; Murugan, Jeff; Nastase, Horatiu

2012-11-02

We present an embedding of the three-dimensional relativistic Landau-Ginzburg model for condensed matter systems in an N = 6, U(N) × U(N) Chern-Simons-matter theory [the Aharony-Bergman-Jafferis-Maldacena model] by consistently truncating the latter to an Abelian effective field theory encoding the collective dynamics of O(N) of the O(N(2)) modes. In fact, depending on the vacuum expectation value on one of the Aharony-Bergman-Jafferis-Maldacena scalars, a mass deformation parameter μ and the Chern-Simons level number k, our Abelianization prescription allows us to interpolate between the Abelian Higgs model with its usual multivortex solutions and a Ø(4) theory. We sketch a simple condensed matter model that reproduces all the salient features of the Abelianization. In this context, the Abelianization can be interpreted as giving a dimensional reduction from four dimensions.

Self-consistent theory of hadron-nucleus scattering. Application to pion physics

International Nuclear Information System (INIS)

Johnson, M.B.

1980-01-01

The requirement of using self-consistent amplitudes to evaluate microscopically the scattering of strongly interacting particles from nuclei is developed. Application of the idea to a simple model of pion-nucleus scattering is made. Numerical results indicate that the expansion of the optical potential converges when evaluated in terms of fully self-consistent quantities. A comparison of the results to a recent determination of the spreading interaction in the phenomenological isobar-hole model shows that the theory accounts for the sign and magnitude of the real and imaginary part of the spreading interaction with no adjusted parameters. The self-consistnt theory has a strong density dependence, and the consequences of this for pion-nucleus scattering are discussed. 18 figures, 1 table

Perspective on rainbow-ladder truncation

International Nuclear Information System (INIS)

Eichmann, G.; Alkofer, R.; Krassnigg, A.; Cloeet, I. C.; Roberts, C. D.

2008-01-01

Prima facie the systematic implementation of corrections to the rainbow-ladder truncation of QCD's Dyson-Schwinger equations will uniformly reduce in magnitude those calculated mass-dimensioned results for pseudoscalar and vector meson properties that are not tightly constrained by symmetries. The aim and interpretation of studies employing rainbow-ladder truncation are reconsidered in this light

Self-consistent perturbed equilibrium with neoclassical toroidal torque in tokamaks

International Nuclear Information System (INIS)

Park, Jong-Kyu; Logan, Nikolas C.

2017-01-01

Toroidal torque is one of the most important consequences of non-axisymmetric fields in tokamaks. The well-known neoclassical toroidal viscosity (NTV) is due to the second-order toroidal force from anisotropic pressure tensor in the presence of these asymmetries. This work shows that the first-order toroidal force originating from the same anisotropic pressure tensor, despite having no flux surface average, can significantly modify the local perturbed force balance and thus must be included in perturbed equilibrium self-consistent with NTV. The force operator with an anisotropic pressure tensor is not self-adjoint when the NTV torque is finite and thus is solved directly for each component. This approach yields a modified, non-self-adjoint Euler-Lagrange equation that can be solved using a variety of common drift-kinetic models in generalized tokamak geometry. The resulting energy and torque integral provides a unique way to construct a torque response matrix, which contains all the information of self-consistent NTV torque profiles obtainable by applying non-axisymmetric fields to the plasma. This torque response matrix can then be used to systematically optimize non-axisymmetric field distributions for desired NTV profiles. Published by AIP Publishing.

Quasiparticle self-consistent GW method for the spectral properties of complex materials.

Science.gov (United States)

Bruneval, Fabien; Gatti, Matteo

2014-01-01

The GW approximation to the formally exact many-body perturbation theory has been applied successfully to materials for several decades. Since the practical calculations are extremely cumbersome, the GW self-energy is most commonly evaluated using a first-order perturbative approach: This is the so-called G 0 W 0 scheme. However, the G 0 W 0 approximation depends heavily on the mean-field theory that is employed as a basis for the perturbation theory. Recently, a procedure to reach a kind of self-consistency within the GW framework has been proposed. The quasiparticle self-consistent GW (QSGW) approximation retains some positive aspects of a self-consistent approach, but circumvents the intricacies of the complete GW theory, which is inconveniently based on a non-Hermitian and dynamical self-energy. This new scheme allows one to surmount most of the flaws of the usual G 0 W 0 at a moderate calculation cost and at a reasonable implementation burden. In particular, the issues of small band gap semiconductors, of large band gap insulators, and of some transition metal oxides are then cured. The QSGW method broadens the range of materials for which the spectral properties can be predicted with confidence.

Multi-component nuclear energy system to meet requirement of self-consistency

International Nuclear Information System (INIS)

Saito, Masaki; Artisyuk, Vladimir; Shmelev, Anotolii; Korovin, Yorii

2000-01-01

Environmental harmonization of nuclear energy technology is considered as an absolutely necessary condition in its future successful development for peaceful use. Establishment of Self-Consistent Nuclear Energy System, that simultaneously meets four requirements - energy production, fuel production, burning of radionuclides and safety, strongly relies on the neutron excess generation. Implementation of external non-fission based neutron sources into fission energy system would open the possibility of approaching Multicomponent Self-Consistent Nuclear Energy System with unlimited fuel resources, zero radioactivity release and high protection against uncontrolled proliferation of nuclear materials. (author)

Symmetric truncations of the shallow-water equations

International Nuclear Information System (INIS)

Rouhi, A.; Abarbanel, H.D.I.

1993-01-01

Conservation of potential vorticity in Eulerian fluids reflects particle interchange symmetry in the Lagrangian fluid version of the same theory. The algebra associated with this symmetry in the shallow-water equations is studied here, and we give a method for truncating the degrees of freedom of the theory which preserves a maximal number of invariants associated with this algebra. The finite-dimensional symmetry associated with keeping only N modes of the shallow-water flow is SU(N). In the limit where the number of modes goes to infinity (N→∞) all the conservation laws connected with potential vorticity conservation are recovered. We also present a Hamiltonian which is invariant under this truncated symmetry and which reduces to the familiar shallow-water Hamiltonian when N→∞. All this provides a finite-dimensional framework for numerical work with the shallow-water equations which preserves not only energy and enstrophy but all other known conserved quantities consistent with the finite number of degrees of freedom. The extension of these ideas to other nearly two-dimensional flows is discussed

Consistent method of truncating the electron self-energy in nonperturbative QED

International Nuclear Information System (INIS)

Rembiesa, P.

1986-01-01

A nonperturbative method of solving the Dyson-Schwinger equations for the fermion propagator is considered. The solution satisfies the Ward-Takahashi identity, allows multiplicative regularization, and exhibits a physical-mass pole

Generalized isothermic lattices

International Nuclear Information System (INIS)

Doliwa, Adam

2007-01-01

We study multi-dimensional quadrilateral lattices satisfying simultaneously two integrable constraints: a quadratic constraint and the projective Moutard constraint. When the lattice is two dimensional and the quadric under consideration is the Moebius sphere one obtains, after the stereographic projection, the discrete isothermic surfaces defined by Bobenko and Pinkall by an algebraic constraint imposed on the (complex) cross-ratio of the circular lattice. We derive the analogous condition for our generalized isothermic lattices using Steiner's projective structure of conics, and we present basic geometric constructions which encode integrability of the lattice. In particular, we introduce the Darboux transformation of the generalized isothermic lattice and we derive the corresponding Bianchi permutability principle. Finally, we study two-dimensional generalized isothermic lattices, in particular geometry of their initial boundary value problem

Clustered survival data with left-truncation

DEFF Research Database (Denmark)

Eriksson, Frank; Martinussen, Torben; Scheike, Thomas H.

2015-01-01

Left-truncation occurs frequently in survival studies, and it is well known how to deal with this for univariate survival times. However, there are few results on how to estimate dependence parameters and regression effects in semiparametric models for clustered survival data with delayed entry....... Surprisingly, existing methods only deal with special cases. In this paper, we clarify different kinds of left-truncation and suggest estimators for semiparametric survival models under specific truncation schemes. The large-sample properties of the estimators are established. Small-sample properties...

Self-consistent chaos in the beam-plasma instability

International Nuclear Information System (INIS)

Tennyson, J.L.; Meiss, J.D.

1993-01-01

The effect of self-consistency on Hamiltonian systems with a large number of degrees-of-freedom is investigated for the beam-plasma instability using the single-wave model of O'Neil, Winfrey, and Malmberg.The single-wave model is reviewed and then rederived within the Hamiltonian context, which leads naturally to canonical action- angle variables. Simulations are performed with a large (10 4 ) number of beam particles interacting with the single wave. It is observed that the system relaxes into a time asymptotic periodic state where only a few collective degrees are active; namely, a clump of trapped particles oscillating in a modulated wave, within a uniform chaotic sea with oscillating phase space boundaries. Thus self-consistency is seen to effectively reduce the number of degrees- of-freedom. A simple low degree-of-freedom model is derived that treats the clump as a single macroparticle, interacting with the wave and chaotic sea. The uniform chaotic sea is modeled by a fluid waterbag, where the waterbag boundaries correspond approximately to invariant tori. This low degree-of-freedom model is seen to compare well with the simulation

Wavelets in self-consistent electronic structure calculations

International Nuclear Information System (INIS)

Wei, S.; Chou, M.Y.

1996-01-01

We report the first implementation of orthonormal wavelet bases in self-consistent electronic structure calculations within the local-density approximation. These local bases of different scales efficiently describe localized orbitals of interest. As an example, we studied two molecules, H 2 and O 2 , using pseudopotentials and supercells. Considerably fewer bases are needed compared with conventional plane-wave approaches, yet calculated binding properties are similar. Our implementation employs fast wavelet and Fourier transforms, avoiding evaluating any three-dimensional integral numerically. copyright 1996 The American Physical Society

Consistency between Self-Reported and Recorded Values for Clinical Measures

OpenAIRE

III, Joseph Thomas; Paulet, Mindy; Rajpura, Jigar R.

2016-01-01

Objectives. This study evaluated consistency between self-reported values for clinical measures and recorded clinical measures. Methods. Self-reported values were collected for the clinical measures: systolic blood pressure, diastolic blood pressure, glucose level, height, weight, and cholesterol from health risk assessments completed by enrollees in a privately insured cohort. Body mass index (BMI) was computed from reported height and weight. Practitioner recorded values for the clinical me...

High-yield water-based synthesis of truncated silver nanocubes

International Nuclear Information System (INIS)

Chang, Yun-Min; Lu, I-Te; Chen, Chih-Yuan; Hsieh, Yu-Chi; Wu, Pu-Wei

2014-01-01

Highlights: • Development of a water-based formula to fabricate truncated Ag nanocubes. • The sample exhibits (1 0 0), (1 1 0), and (1 1 1) on the facets, edges, and corners. • The sample shows three characteristic absorption peaks due to plasma resonance. -- Abstract: A high-yield water-based hydrothermal synthesis was developed using silver nitrate, ammonia, glucose, and cetyltrimethylammonium bromide (CTAB) as precursors to synthesize truncated silver nanocubes with uniform sizes and in large quantities. With a fixed CTAB concentration, truncated silver nanocubes with sizes of 49.3 ± 4.1 nm were produced when the molar ratio of glucose/silver cation was maintained at 0.1. The sample exhibited (1 0 0), (1 1 0), and (1 1 1) planes on the facets, edges, and corners, respectively. In contrast, with a slightly larger glucose/silver cation ratio of 0.35, well-defined nanocubes with sizes of 70.9 ± 3.8 nm sizes were observed with the (1 0 0) plane on six facets. When the ratio was further increased to 1.5, excess reduction of silver cations facilitated the simultaneous formation of nanoparticles with cubic, spherical, and irregular shapes. Consistent results were obtained from transmission electron microscopy, scanning electron microscopy, X-ray diffraction, and UV–visible absorption measurements

High-yield water-based synthesis of truncated silver nanocubes

Energy Technology Data Exchange (ETDEWEB)

Chang, Yun-Min; Lu, I-Te; Chen, Chih-Yuan; Hsieh, Yu-Chi; Wu, Pu-Wei, E-mail: ppwu@mail.nctu.edu.tw

2014-02-15

Highlights: • Development of a water-based formula to fabricate truncated Ag nanocubes. • The sample exhibits (1 0 0), (1 1 0), and (1 1 1) on the facets, edges, and corners. • The sample shows three characteristic absorption peaks due to plasma resonance. -- Abstract: A high-yield water-based hydrothermal synthesis was developed using silver nitrate, ammonia, glucose, and cetyltrimethylammonium bromide (CTAB) as precursors to synthesize truncated silver nanocubes with uniform sizes and in large quantities. With a fixed CTAB concentration, truncated silver nanocubes with sizes of 49.3 ± 4.1 nm were produced when the molar ratio of glucose/silver cation was maintained at 0.1. The sample exhibited (1 0 0), (1 1 0), and (1 1 1) planes on the facets, edges, and corners, respectively. In contrast, with a slightly larger glucose/silver cation ratio of 0.35, well-defined nanocubes with sizes of 70.9 ± 3.8 nm sizes were observed with the (1 0 0) plane on six facets. When the ratio was further increased to 1.5, excess reduction of silver cations facilitated the simultaneous formation of nanoparticles with cubic, spherical, and irregular shapes. Consistent results were obtained from transmission electron microscopy, scanning electron microscopy, X-ray diffraction, and UV–visible absorption measurements.

Self-consistent studies of magnetic thin film Ni (001)

International Nuclear Information System (INIS)

Wang, C.S.; Freeman, A.J.

1979-01-01

Advances in experimental methods for studying surface phenomena have provided the stimulus to develop theoretical methods capable of interpreting this wealth of new information. Of particular interest have been the relative roles of bulk and surface contributions since in several important cases agreement between experiment and bulk self-consistent (SC) calculations within the local spin density functional formalism (LSDF) is lacking. We discuss our recent extension of the (LSDF) approach to the study of thin films (slabs) and the role of surface effects on magnetic properties. Results are described for Ni (001) films using our new SC numerical basis set LCAO method. Self-consistency within the superposition of overlapping spherical atomic charge density model is obtained iteratively with the atomic configuration as the adjustable parameter. Results are presented for the electronic charge densities and local density of states. The origin and role of (magnetic) surface states is discussed by comparison with results of earlier bulk calculations

False memory production :effects of self-consistent false information and motivated cognition

OpenAIRE

Brown, Martha

1996-01-01

Remembrance of one's personal past and the development of false memories have recently received intense public scrutiny. Based upon self-schema (Markus, 1977) and selfverification (Swann, 1987) theories, two studies were conducted to investigate the hypothesis that a self-schema guides cognitive processing of self-relevant information and thereby influences the construction of a memory that includes false information, particularly more so if this information is self-schema consistent than ...

Applicability of self-consistent mean-field theory

International Nuclear Information System (INIS)

Guo Lu; Sakata, Fumihiko; Zhao Enguang

2005-01-01

Within the constrained Hartree-Fock (CHF) theory, an analytic condition is derived to estimate whether a concept of the self-consistent mean field is realized in the level repulsive region. The derived condition states that an iterative calculation of the CHF equation does not converge when the quantum fluctuations coming from two-body residual interaction and quadrupole deformation become larger than a single-particle energy difference between two avoided crossing orbits. By means of numerical calculation, it is shown that the analytic condition works well for a realistic case

Self-consistent potential variations in magnetic wells

International Nuclear Information System (INIS)

Kesner, J.; Knorr, G.; Nicholson, D.R.

1981-01-01

Self-consistent electrostatic potential variations are considered in a spatial region of weak magnetic field, as in the proposed tandem mirror thermal barriers (with no trapped ions). For some conditions, equivalent to ion distributions with a sufficiently high net drift speed along the magnetic field, the desired potential depressions are found. When the net drift speed is not high enough, potential depressions are found only in combination with strong electric fields on the boundaries of the system. These potential depressions are not directly related to the magnetic field depression. (author)

Self-consistent gyrokinetic modeling of neoclassical and turbulent impurity transport

Science.gov (United States)

Estève, D.; Sarazin, Y.; Garbet, X.; Grandgirard, V.; Breton, S.; Donnel, P.; Asahi, Y.; Bourdelle, C.; Dif-Pradalier, G.; Ehrlacher, C.; Emeriau, C.; Ghendrih, Ph.; Gillot, C.; Latu, G.; Passeron, C.

2018-03-01

Trace impurity transport is studied with the flux-driven gyrokinetic GYSELA code (Grandgirard et al 2016 Comput. Phys. Commun. 207 35). A reduced and linearized multi-species collision operator has been recently implemented, so that both neoclassical and turbulent transport channels can be treated self-consistently on an equal footing. In the Pfirsch-Schlüter regime that is probably relevant for tungsten, the standard expression for the neoclassical impurity flux is shown to be recovered from gyrokinetics with the employed collision operator. Purely neoclassical simulations of deuterium plasma with trace impurities of helium, carbon and tungsten lead to impurity diffusion coefficients, inward pinch velocities due to density peaking, and thermo-diffusion terms which quantitatively agree with neoclassical predictions and NEO simulations (Belli et al 2012 Plasma Phys. Control. Fusion 54 015015). The thermal screening factor appears to be less than predicted analytically in the Pfirsch-Schlüter regime, which can be detrimental to fusion performance. Finally, self-consistent nonlinear simulations have revealed that the tungsten impurity flux is not the sum of turbulent and neoclassical fluxes computed separately, as is usually assumed. The synergy partly results from the turbulence-driven in-out poloidal asymmetry of tungsten density. This result suggests the need for self-consistent simulations of impurity transport, i.e. including both turbulence and neoclassical physics, in view of quantitative predictions for ITER.

Simulations of Tokamak Edge Turbulence Including Self-Consistent Zonal Flows

Science.gov (United States)

Cohen, Bruce; Umansky, Maxim

2013-10-01

Progress on simulations of electromagnetic drift-resistive ballooning turbulence in the tokamak edge is summarized in this mini-conference talk. A more detailed report on this work is presented in a poster at this conference. This work extends our previous work to include self-consistent zonal flows and their effects. The previous work addressed the simulation of L-mode tokamak edge turbulence using the turbulence code BOUT. The calculations used realistic single-null geometry and plasma parameters of the DIII-D tokamak and produced fluctuation amplitudes, fluctuation spectra, and particle and thermal fluxes that compare favorably to experimental data. In the effect of sheared ExB poloidal rotation is included with an imposed static radial electric field fitted to experimental data. In the new work here we include the radial electric field self-consistently driven by the microturbulence, which contributes to the sheared ExB poloidal rotation (zonal flow generation). We present simulations with/without zonal flows for both cylindrical geometry, as in the UCLA Large Plasma Device, and for the DIII-D tokamak L-mode cases in to quantify the influence of self-consistent zonal flows on the microturbulence and the concomitant transport. This work was performed under the auspices of the US Department of Energy under contract DE-AC52-07NA27344 at the Lawrence Livermore National Laboratory.

Truncation correction for oblique filtering lines

International Nuclear Information System (INIS)

Hoppe, Stefan; Hornegger, Joachim; Lauritsch, Guenter; Dennerlein, Frank; Noo, Frederic

2008-01-01

State-of-the-art filtered backprojection (FBP) algorithms often define the filtering operation to be performed along oblique filtering lines in the detector. A limited scan field of view leads to the truncation of those filtering lines, which causes artifacts in the final reconstructed volume. In contrast to the case where filtering is performed solely along the detector rows, no methods are available for the case of oblique filtering lines. In this work, the authors present two novel truncation correction methods which effectively handle data truncation in this case. Method 1 (basic approach) handles data truncation in two successive preprocessing steps by applying a hybrid data extrapolation method, which is a combination of a water cylinder extrapolation and a Gaussian extrapolation. It is independent of any specific reconstruction algorithm. Method 2 (kink approach) uses similar concepts for data extrapolation as the basic approach but needs to be integrated into the reconstruction algorithm. Experiments are presented from simulated data of the FORBILD head phantom, acquired along a partial-circle-plus-arc trajectory. The theoretically exact M-line algorithm is used for reconstruction. Although the discussion is focused on theoretically exact algorithms, the proposed truncation correction methods can be applied to any FBP algorithm that exposes oblique filtering lines.

Link between self-consistent pressure profiles and electron internal transport barriers in tokamaks

Energy Technology Data Exchange (ETDEWEB)

Razumova, K A [Nuclear Fusion Institute, RRC ' Kurchatov Institute' , 123182 Moscow (Russian Federation); Andreev, V F [Nuclear Fusion Institute, RRC ' Kurchatov Institute' , 123182 Moscow (Russian Federation); Donne, A J H [FOM-Institute for Plasma Physics Rijnhuizen, Association EURATOM-FOM, partner in the Trilateral Euregio Cluster, PO Box 1207, 3430 BE Nieuwegein (Netherlands); Hogeweij, G M D [FOM-Institute for Plasma Physics Rijnhuizen, Association EURATOM-FOM, partner in the Trilateral Euregio Cluster, PO Box 1207, 3430 BE Nieuwegein (Netherlands); Lysenko, S E [Nuclear Fusion Institute, RRC ' Kurchatov Institute' , 123182 Moscow (Russian Federation); Shelukhin, D A [Nuclear Fusion Institute, RRC ' Kurchatov Institute' , 123182 Moscow (Russian Federation); Spakman, G W [FOM-Institute for Plasma Physics Rijnhuizen, Association EURATOM-FOM, partner in the Trilateral Euregio Cluster, PO Box 1207, 3430 BE Nieuwegein (Netherlands); Vershkov, V A [Nuclear Fusion Institute, RRC ' Kurchatov Institute' , 123182 Moscow (Russian Federation); Zhuravlev, V A [Nuclear Fusion Institute, RRC ' Kurchatov Institute' , 123182 Moscow (Russian Federation)

2006-09-15

Tokamak plasmas have a tendency to self-organization: the plasma pressure profiles obtained in different operational regimes and even in various tokamaks may be represented by a single typical curve, called the self-consistent pressure profile. About a decade ago local zones with enhanced confinement were discovered in tokamak plasmas. These zones are referred to as internal transport barriers (ITBs) and they can act on the electron and/or ion fluid. Here the pressure gradients can largely exceed the gradients dictated by profile consistency. So the existence of ITBs seems to be in contradiction with the self-consistent pressure profiles (this is also often referred to as profile resilience or profile stiffness). In this paper we will discuss the interplay between profile consistency and ITBs. A summary of the cumulative information obtained from T-10, RTP and TEXTOR is given, and a coherent explanation of the main features of the observed phenomena is suggested. Both phenomena, the self-consistent profile and ITB, are connected with the density of rational magnetic surfaces, where the turbulent cells are situated. The distance between these cells determines the level of their interaction, and therefore the level of the turbulent transport. This process regulates the plasma pressure profile. If the distance is wide, the turbulent flux may be diminished and the ITB may be formed. In regions with rarefied surfaces the steeper pressure gradients are possible without instantaneously inducing pressure driven instabilities, which force the profiles back to their self-consistent shapes. Also it can be expected that the ITB region is wider for lower dq/d{rho} (more rarefied surfaces)

Generation of static solutions of self-consistent system of Einstein-Maxwell equations

International Nuclear Information System (INIS)

Anchikov, A.M.; Daishev, R.A.

1988-01-01

The theorem, according to which the static solution of the self-consistent system of the Einstein-Maxwell equations is assigned to energy static solution of the Einstein equations with the arbitrary energy-momentum tensor in the right part, is proved. As a consequence of this theorem, the way of the generation of the static solutions of the self-consistent system of the Einstein-Maxwell equations with charged dust as a source of the vacuum solutions of the Einstein equations is shown

Model-free method for isothermal and non-isothermal decomposition kinetics analysis of PET sample

International Nuclear Information System (INIS)

Saha, B.; Maiti, A.K.; Ghoshal, A.K.

2006-01-01

Pyrolysis, one possible alternative to recover valuable products from waste plastics, has recently been the subject of renewed interest. In the present study, the isoconversion methods, i.e., Vyazovkin model-free approach is applied to study non-isothermal decomposition kinetics of waste PET samples using various temperature integral approximations such as Coats and Redfern, Gorbachev, and Agrawal and Sivasubramanian approximation and direct integration (recursive adaptive Simpson quadrature scheme) to analyze the decomposition kinetics. The results show that activation energy (E α ) is a weak but increasing function of conversion (α) in case of non-isothermal decomposition and strong and decreasing function of conversion in case of isothermal decomposition. This indicates possible existence of nucleation, nuclei growth and gas diffusion mechanism during non-isothermal pyrolysis and nucleation and gas diffusion mechanism during isothermal pyrolysis. Optimum E α dependencies on α obtained for non-isothermal data showed similar nature for all the types of temperature integral approximations

Modeling the Effect of APC Truncation on Destruction Complex Function in Colorectal Cancer Cells

Science.gov (United States)

Barua, Dipak; Hlavacek, William S.

2013-01-01

In colorectal cancer cells, APC, a tumor suppressor protein, is commonly expressed in truncated form. Truncation of APC is believed to disrupt degradation of β—catenin, which is regulated by a multiprotein complex called the destruction complex. The destruction complex comprises APC, Axin, β—catenin, serine/threonine kinases, and other proteins. The kinases and , which are recruited by Axin, mediate phosphorylation of β—catenin, which initiates its ubiquitination and proteosomal degradation. The mechanism of regulation of β—catenin degradation by the destruction complex and the role of truncation of APC in colorectal cancer are not entirely understood. Through formulation and analysis of a rule-based computational model, we investigated the regulation of β—catenin phosphorylation and degradation by APC and the effect of APC truncation on function of the destruction complex. The model integrates available mechanistic knowledge about site-specific interactions and phosphorylation of destruction complex components and is consistent with an array of published data. We find that the phosphorylated truncated form of APC can outcompete Axin for binding to β—catenin, provided that Axin is limiting, and thereby sequester β—catenin away from Axin and the Axin-recruited kinases and . Full-length APC also competes with Axin for binding to β—catenin; however, full-length APC is able, through its SAMP repeats, which bind Axin and which are missing in truncated oncogenic forms of APC, to bring β—catenin into indirect association with Axin and Axin-recruited kinases. Because our model indicates that the positive effects of truncated APC on β—catenin levels depend on phosphorylation of APC, at the first 20-amino acid repeat, and because phosphorylation of this site is mediated by , we suggest that is a potential target for therapeutic intervention in colorectal cancer. Specific inhibition of is predicted to limit binding of β—catenin to truncated

On the Minimax Value in the Scale Model with Truncated Data

OpenAIRE

Gajek, Leslaw

1988-01-01

Let $X$ be a positive random variable with Lebesgue density $f_\\theta(x)$, where $\\theta$ is the scale parameter, and let $Y$ be a positive random variable independent of $X$. We consider two models of truncation: the LHS model, where the data consist only of those observations of $X$ for which $X > Y$; and the RHS model, where the data consist of those observations of $X$ for which $X \\leq Y$. Consider the problem of estimating $\\theta^s, s \

Water is a poor solvent for densely grafted poly(ethylene oxide) chains: a conclusion drawn from a self-consistent field theory-based analysis of neutron reflectivity and surface pressure-area isotherm data.

Science.gov (United States)

Lee, Hoyoung; Kim, Dae Hwan; Witte, Kevin N; Ohn, Kimberly; Choi, Je; Akgun, Bulent; Satija, Sushil; Won, You-Yeon

2012-06-21

By use of a combined experimental and theoretical approach, a model poly(ethylene oxide) (PEO) brush system, prepared by spreading a poly(ethylene oxide)-poly(n-butyl acrylate) (PEO-PnBA) amphiphilic diblock copolymer onto an air-water interface, was investigated. The polymer segment density profiles of the PEO brush in the direction normal to the air-water interface under various grafting density conditions were determined by using the neutron reflectivity (NR) measurement technique. To achieve a theoretically sound analysis of the reflectivity data, we used a data analysis method that utilizes the self-consistent field (SCF) theoretical modeling as a tool for predicting expected reflectivity results for comparison with the experimental data. Using this data analysis technique, we discovered that the effective Flory-Huggins interaction parameter of the PEO brush chains is significantly greater than that corresponding to the θ condition in Flory-Huggins solutions (i.e., χ(PEO-water)(brush chains)/χ(PEO-water)(θ condition) ≈ 1.2), suggesting that contrary to what is more commonly observed for PEO in normal situations (χ(PEO-water)(free chains)/χ(PEO-water)(θ condition) ≈ 0.92), the PEO chains are actually not "hydrophilic" when they exist as polymer brush chains, because of the many body interactions that are forced to be effective in the brush situation. This result is further supported by the fact that the surface pressures of the PEO brush calculated on the basis of the measured χ(PEO-water) value are in close agreement with the experimental surface pressure-area isotherm data. The SCF theoretical analysis of the surface pressure behavior of the PEO brush also suggests that even though the grafted PEO chains experience a poor solvent environment, the PEO brush layer exhibits positive surface pressures, because the hydrophobicity of the PEO brush chains (which favors compression) is insufficient to overcome the opposing effect of the chain

The numerical multiconfiguration self-consistent field approach for atoms; Der numerische Multiconfiguration Self-Consistent Field-Ansatz fuer Atome

Energy Technology Data Exchange (ETDEWEB)

Stiehler, Johannes

1995-12-15

The dissertation uses the Multiconfiguration Self-Consistent Field Approach to specify the electronic wave function of N electron atoms in a static electrical field. It presents numerical approaches to describe the wave functions and introduces new methods to compute the numerical Fock equations. Based on results computed with an implemented computer program the universal application, flexibility and high numerical precision of the presented approach is shown. RHF results and for the first time MCSCF results for polarizabilities and hyperpolarizabilities of various states of the atoms He to Kr are discussed. In addition, an application to interpret a plasma spectrum of gallium is presented. (orig.)

Self-consistent field variational cellular method as applied to the band structure calculation of sodium

International Nuclear Information System (INIS)

Lino, A.T.; Takahashi, E.K.; Leite, J.R.; Ferraz, A.C.

1988-01-01

The band structure of metallic sodium is calculated, using for the first time the self-consistent field variational cellular method. In order to implement the self-consistency in the variational cellular theory, the crystal electronic charge density was calculated within the muffin-tin approximation. The comparison between our results and those derived from other calculations leads to the conclusion that the proposed self-consistent version of the variational cellular method is fast and accurate. (author) [pt

Self-consistent green function calculations for isospin asymmetric nuclear matter

International Nuclear Information System (INIS)

Mansour, Hesham; Gad, Khalaf; Hassaneen, Khaled S.A.

2010-01-01

The one-body potentials for protons and neutrons are obtained from the self-consistent Green-function calculations of asymmetric nuclear matter, in particular their dependence on the degree of proton/neutron asymmetry. Results of the binding energy per nucleon as a function of the density and asymmetry parameter are presented for the self-consistent Green function approach using the CD-Bonn potential. For the sake of comparison, the same calculations are performed using the Brueckner-Hartree-Fock approximation. The contribution of the hole-hole terms leads to a repulsive contribution to the energy per nucleon which increases with the nuclear density. The incompressibility for asymmetric nuclear matter has been also investigated in the framework of the self-consistent Green-function approach using the CD-Bonn potential. The behavior of the incompressibility is studied for different values of the nuclear density and the neutron excess parameter. The nuclear symmetry potential at fixed nuclear density is also calculated and its value decreases with increasing the nucleon energy. In particular, the nuclear symmetry potential at saturation density changes from positive to negative values at nucleon kinetic energy of about 200 MeV. For the sake of comparison, the same calculations are performed using the Brueckner-Hartree-Fock approximation. The proton/neutron effective mass splitting in neutron-rich matter has been studied. The predicted isospin splitting of the proton/neutron effective mass splitting in neutron-rich matter is such that m n * ≥ m p * . (author)

Self-consistent approach to the eletronic problem in disordered solids

International Nuclear Information System (INIS)

Taguena-Martinez, J.; Barrio, R.A.; Martinez, E.; Yndurain, F.

1984-01-01

It is developed a simple formalism which allows us to perform a self consistent non-parametrized calculation in a non-periodic system, by finding out the thermodynamically averaged Green's function of a cluster Bethe lattice system. (Author) [pt

Self-consistent calculation of 208Pb spectrum

International Nuclear Information System (INIS)

Pal'chik, V.V.; Pyatov, N.I.; Fayans, S.A.

1981-01-01

The self-consistent model with exact accounting for one-particle continuum is applied to calculate all discrete particle-hole natural parity states with 2 208 Pb nucleus (up to the neutron emission threshold, 7.4 MeV). Contributions to the energy-weighted sum rules S(EL) of the first collective levels and total contributions of all discrete levels are evaluated. Most strongly the collectivization is manifested for octupole states. With multipolarity growth L contributions of discrete levels are sharply reduced. The results are compared with other models and the experimental data obtained in (e, e'), (p, p') reactions and other data [ru

Self-consistent modeling of electron cyclotron resonance ion sources

International Nuclear Information System (INIS)

Girard, A.; Hitz, D.; Melin, G.; Serebrennikov, K.; Lecot, C.

2004-01-01

In order to predict the performances of electron cyclotron resonance ion source (ECRIS), it is necessary to perfectly model the different parts of these sources: (i) magnetic configuration; (ii) plasma characteristics; (iii) extraction system. The magnetic configuration is easily calculated via commercial codes; different codes also simulate the ion extraction, either in two dimension, or even in three dimension (to take into account the shape of the plasma at the extraction influenced by the hexapole). However the characteristics of the plasma are not always mastered. This article describes the self-consistent modeling of ECRIS: we have developed a code which takes into account the most important construction parameters: the size of the plasma (length, diameter), the mirror ratio and axial magnetic profile, whether a biased probe is installed or not. These input parameters are used to feed a self-consistent code, which calculates the characteristics of the plasma: electron density and energy, charge state distribution, plasma potential. The code is briefly described, and some of its most interesting results are presented. Comparisons are made between the calculations and the results obtained experimentally

Self-consistent modeling of electron cyclotron resonance ion sources

Science.gov (United States)

Girard, A.; Hitz, D.; Melin, G.; Serebrennikov, K.; Lécot, C.

2004-05-01

In order to predict the performances of electron cyclotron resonance ion source (ECRIS), it is necessary to perfectly model the different parts of these sources: (i) magnetic configuration; (ii) plasma characteristics; (iii) extraction system. The magnetic configuration is easily calculated via commercial codes; different codes also simulate the ion extraction, either in two dimension, or even in three dimension (to take into account the shape of the plasma at the extraction influenced by the hexapole). However the characteristics of the plasma are not always mastered. This article describes the self-consistent modeling of ECRIS: we have developed a code which takes into account the most important construction parameters: the size of the plasma (length, diameter), the mirror ratio and axial magnetic profile, whether a biased probe is installed or not. These input parameters are used to feed a self-consistent code, which calculates the characteristics of the plasma: electron density and energy, charge state distribution, plasma potential. The code is briefly described, and some of its most interesting results are presented. Comparisons are made between the calculations and the results obtained experimentally.

Doubly self-consistent field theory of grafted polymers under simple shear in steady state

International Nuclear Information System (INIS)

Suo, Tongchuan; Whitmore, Mark D.

2014-01-01

We present a generalization of the numerical self-consistent mean-field theory of polymers to the case of grafted polymers under simple shear. The general theoretical framework is presented, and then applied to three different chain models: rods, Gaussian chains, and finitely extensible nonlinear elastic (FENE) chains. The approach is self-consistent at two levels. First, for any flow field, the polymer density profile and effective potential are calculated self-consistently in a manner similar to the usual self-consistent field theory of polymers, except that the calculation is inherently two-dimensional even for a laterally homogeneous system. Second, through the use of a modified Brinkman equation, the flow field and the polymer profile are made self-consistent with respect to each other. For all chain models, we find that reasonable levels of shear cause the chains to tilt, but it has very little effect on the overall thickness of the polymer layer, causing a small decrease for rods, and an increase of no more than a few percent for the Gaussian and FENE chains. Using the FENE model, we also probe the individual bond lengths, bond correlations, and bond angles along the chains, the effects of the shear on them, and the solvent and bonded stress profiles. We find that the approximations needed within the theory for the Brinkman equation affect the bonded stress, but none of the other quantities

Truncated Painleve expansion: Tanh-traveling wave solutions and reduction of sine-Poisson equation to a quadrature for stationary and nonstationary three-dimensional collisionless cold plasma

International Nuclear Information System (INIS)

Ibrahim, R. S.; El-Kalaawy, O. H.

2006-01-01

The relativistic nonlinear self-consistent equations for a collisionless cold plasma with stationary ions [R. S. Ibrahim, IMA J. Appl. Math. 68, 523 (2003)] are extended to 3 and 3+1 dimensions. The resulting system of equations is reduced to the sine-Poisson equation. The truncated Painleve expansion and reduction of the partial differential equation to a quadrature problem (RQ method) are described and applied to obtain the traveling wave solutions of the sine-Poisson equation for stationary and nonstationary equations in 3 and 3+1 dimensions describing the charge-density equilibrium configuration model

A self-consistent semiclassical sum rule approach to the average properties of giant resonances

International Nuclear Information System (INIS)

Li Guoqiang; Xu Gongou

1990-01-01

The average energies of isovector giant resonances and the widths of isoscalar giant resonances are evaluated with the help of a self-consistent semiclassical Sum rule approach. The comparison of the present results with the experimental ones justifies the self-consistent semiclassical sum rule approach to the average properties of giant resonances

Self-consistent field model for strong electrostatic correlations and inhomogeneous dielectric media.

Science.gov (United States)

Ma, Manman; Xu, Zhenli

2014-12-28

Electrostatic correlations and variable permittivity of electrolytes are essential for exploring many chemical and physical properties of interfaces in aqueous solutions. We propose a continuum electrostatic model for the treatment of these effects in the framework of the self-consistent field theory. The model incorporates a space- or field-dependent dielectric permittivity and an excluded ion-size effect for the correlation energy. This results in a self-energy modified Poisson-Nernst-Planck or Poisson-Boltzmann equation together with state equations for the self energy and the dielectric function. We show that the ionic size is of significant importance in predicting a finite self energy for an ion in an inhomogeneous medium. Asymptotic approximation is proposed for the solution of a generalized Debye-Hückel equation, which has been shown to capture the ionic correlation and dielectric self energy. Through simulating ionic distribution surrounding a macroion, the modified self-consistent field model is shown to agree with particle-based Monte Carlo simulations. Numerical results for symmetric and asymmetric electrolytes demonstrate that the model is able to predict the charge inversion at high correlation regime in the presence of multivalent interfacial ions which is beyond the mean-field theory and also show strong effect to double layer structure due to the space- or field-dependent dielectric permittivity.

Self-consistent field model for strong electrostatic correlations and inhomogeneous dielectric media

Energy Technology Data Exchange (ETDEWEB)

Ma, Manman, E-mail: mmm@sjtu.edu.cn; Xu, Zhenli, E-mail: xuzl@sjtu.edu.cn [Department of Mathematics, Institute of Natural Sciences, and MoE Key Laboratory of Scientific and Engineering Computing, Shanghai Jiao Tong University, Shanghai 200240 (China)

2014-12-28

Electrostatic correlations and variable permittivity of electrolytes are essential for exploring many chemical and physical properties of interfaces in aqueous solutions. We propose a continuum electrostatic model for the treatment of these effects in the framework of the self-consistent field theory. The model incorporates a space- or field-dependent dielectric permittivity and an excluded ion-size effect for the correlation energy. This results in a self-energy modified Poisson-Nernst-Planck or Poisson-Boltzmann equation together with state equations for the self energy and the dielectric function. We show that the ionic size is of significant importance in predicting a finite self energy for an ion in an inhomogeneous medium. Asymptotic approximation is proposed for the solution of a generalized Debye-Hückel equation, which has been shown to capture the ionic correlation and dielectric self energy. Through simulating ionic distribution surrounding a macroion, the modified self-consistent field model is shown to agree with particle-based Monte Carlo simulations. Numerical results for symmetric and asymmetric electrolytes demonstrate that the model is able to predict the charge inversion at high correlation regime in the presence of multivalent interfacial ions which is beyond the mean-field theory and also show strong effect to double layer structure due to the space- or field-dependent dielectric permittivity.

Macroscopic self-consistent model for external-reflection near-field microscopy

International Nuclear Information System (INIS)

Berntsen, S.; Bozhevolnaya, E.; Bozhevolnyi, S.

1993-01-01

The self-consistent macroscopic approach based on the Maxwell equations in two-dimensional geometry is developed to describe tip-surface interaction in external-reflection near-field microscopy. The problem is reduced to a single one-dimensional integral equation in terms of the Fourier components of the field at the plane of the sample surface. This equation is extended to take into account a pointlike scatterer placed on the sample surface. The power of light propagating toward the detector as the fiber mode is expressed by using the self-consistent field at the tip surface. Numerical results for trapezium-shaped tips are presented. The authors show that the sharper tip and the more confined fiber mode result in better resolution of the near-field microscope. Moreover, it is found that the tip-surface distance should not be too small so that better resolution is ensured. 14 refs., 10 figs

Self-consistent viscous heating of rapidly compressed turbulence

Science.gov (United States)

Campos, Alejandro; Morgan, Brandon

2017-11-01

Given turbulence subjected to infinitely rapid deformations, linear terms representing interactions between the mean flow and the turbulence dictate the evolution of the flow, whereas non-linear terms corresponding to turbulence-turbulence interactions are safely ignored. For rapidly deformed flows where the turbulence Reynolds number is not sufficiently large, viscous effects can't be neglected and tend to play a prominent role, as shown in the study of Davidovits & Fisch (2016). For such a case, the rapid increase of viscosity in a plasma-as compared to the weaker scaling of viscosity in a fluid-leads to the sudden viscous dissipation of turbulent kinetic energy. As shown in Davidovits & Fisch, increases in temperature caused by the direct compression of the plasma drive sufficiently large values of viscosity. We report on numerical simulations of turbulence where the increase in temperature is the result of both the direct compression (an inviscid mechanism) and the self-consistent viscous transfer of energy from the turbulent scales towards the thermal energy. A comparison between implicit large-eddy simulations against well-resolved direct numerical simulations is included to asses the effect of the numerical and subgrid-scale dissipation on the self-consistent viscous This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

Bosons system with finite repulsive interaction: self-consistent field method

International Nuclear Information System (INIS)

Renatino, M.M.B.

1983-01-01

Some static properties of a boson system (T = zero degree Kelvin), under the action of a repulsive potential are studied. For the repulsive potential, a model was adopted consisting of a region where it is constant (r c ), and a decay as 1/r (r > r c ). The self-consistent field approximation used takes into account short range correlations through a local field corrections, which leads to an effective field. The static structure factor S(q-vector) and the effective potential ψ(q-vector) are obtained through a self-consistent calculation. The pair-correlation function g(r-vector) and the energy of the collective excitations E(q-vector) are also obtained, from the structure factor. The density of the system and the parameters of the repulsive potential, that is, its height and the size of the constant region were used as variables for the problem. The results obtained for S(q-vector), g(r-vector) and E(q-vector) for a fixed ratio r o /r c and a variable λ, indicates the raising of a system structure, which is more noticeable when the potential became more repulsive. (author)

The influence of thermodynamic self-consistency on the phase behaviour of symmetric binary mixtures

CERN Document Server

Scholl-Paschinger, E; Kahl, G

2004-01-01

We have investigated the phase behaviour of a symmetric binary mixture with particles interacting via hard-core Yukawa potentials. To calculate the thermodynamic properties we have used the mean spherical approximation (MSA), a conventional liquid state theory, and the closely related self-consistent Ornstein-Zernike approximation which is defined via an MSA-type closure relation, requiring, in addition, thermodynamic self-consistency between the compressibility and the energy-route. We investigate on a quantitative level the effect of the self-consistency requirement on the phase diagram and on the critical behaviour and confirm the existence of three archetypes of phase diagram, which originate from the competition between the first order liquid/vapour transition and the second order demixing transition.

Analysis of the upper-truncated Weibull distribution for wind speed

International Nuclear Information System (INIS)

Kantar, Yeliz Mert; Usta, Ilhan

2015-01-01

Highlights: • Upper-truncated Weibull distribution is proposed to model wind speed. • Upper-truncated Weibull distribution nests Weibull distribution as special case. • Maximum likelihood is the best method for upper-truncated Weibull distribution. • Fitting accuracy of upper-truncated Weibull is analyzed on wind speed data. - Abstract: Accurately modeling wind speed is critical in estimating the wind energy potential of a certain region. In order to model wind speed data smoothly, several statistical distributions have been studied. Truncated distributions are defined as a conditional distribution that results from restricting the domain of statistical distribution and they also cover base distribution. This paper proposes, for the first time, the use of upper-truncated Weibull distribution, in modeling wind speed data and also in estimating wind power density. In addition, a comparison is made between upper-truncated Weibull distribution and well known Weibull distribution using wind speed data measured in various regions of Turkey. The obtained results indicate that upper-truncated Weibull distribution shows better performance than Weibull distribution in estimating wind speed distribution and wind power. Therefore, upper-truncated Weibull distribution can be an alternative for use in the assessment of wind energy potential

Self-consistent theory of hadron-nucleus scattering. Application to pion physics

International Nuclear Information System (INIS)

Johnson, M.B.

1981-01-01

The first part of this set of two seminars will consist of a review of several of the important accomplishments made in the last few years in the field of pion-nucleus physics. Next I discuss some questions raised by these accomplishments and show that for some very natural reasons the commonly employed theoretical methods cannot be applied to answer these questions. This situation leads to the idea of self-consistency, which is first explained in a general context. The remainder of the seminars are devoted to illustrating the idea within a simple multiple-scattering model for the case of pion scattering. An evaluation of the effectiveness of the self-consistent requirment to produce a solution to the model is made, and a few of the questions raised by recent accomplishments in the field of pion physics are addressed in the model. Finally, the results of the model calculation are compared to experimental data and implications of the results discussed. (orig./HSI)

Final Report Fermionic Symmetries and Self consistent Shell Model

International Nuclear Information System (INIS)

Zamick, Larry

2008-01-01

In this final report in the field of theoretical nuclear physics we note important accomplishments.We were confronted with 'anomoulous' magnetic moments by the experimetalists and were able to expain them. We found unexpected partial dynamical symmetries--completely unknown before, and were able to a large extent to expain them. The importance of a self consistent shell model was emphasized.

Charge neutralization as the major factor for the assembly of nucleocapsid-like particles from C-terminal truncated hepatitis C virus core protein.

Science.gov (United States)

de Souza, Theo Luiz Ferraz; de Lima, Sheila Maria Barbosa; Braga, Vanessa L de Azevedo; Peabody, David S; Ferreira, Davis Fernandes; Bianconi, M Lucia; Gomes, Andre Marco de Oliveira; Silva, Jerson Lima; de Oliveira, Andréa Cheble

2016-01-01

Hepatitis C virus (HCV) core protein, in addition to its structural role to form the nucleocapsid assembly, plays a critical role in HCV pathogenesis by interfering in several cellular processes, including microRNA and mRNA homeostasis. The C-terminal truncated HCV core protein (C124) is intrinsically unstructured in solution and is able to interact with unspecific nucleic acids, in the micromolar range, and to assemble into nucleocapsid-like particles (NLPs) in vitro . The specificity and propensity of C124 to the assembly and its implications on HCV pathogenesis are not well understood. Spectroscopic techniques, transmission electron microscopy and calorimetry were used to better understand the propensity of C124 to fold or to multimerize into NLPs when subjected to different conditions or in the presence of unspecific nucleic acids of equivalent size to cellular microRNAs. The structural analysis indicated that C124 has low propensity to self-folding. On the other hand, for the first time, we show that C124, in the absence of nucleic acids, multimerizes into empty NLPs when subjected to a pH close to its isoelectric point (pH ≈ 12), indicating that assembly is mainly driven by charge neutralization. Isothermal calorimetry data showed that the assembly of NLPs promoted by nucleic acids is enthalpy driven. Additionally, data obtained from fluorescence correlation spectroscopy show that C124, in nanomolar range, was able to interact and to sequester a large number of short unspecific nucleic acids into NLPs. Together, our data showed that the charge neutralization is the major factor for the nucleocapsid-like particles assembly from C-terminal truncated HCV core protein. This finding suggests that HCV core protein may physically interact with unspecific cellular polyanions, which may correspond to microRNAs and mRNAs in a host cell infected by HCV, triggering their confinement into infectious particles.

Correlations and self-consistency in pion scattering. II

International Nuclear Information System (INIS)

Johnson, M.B.; Keister, B.D.

1978-01-01

In an attempt to overcome certain difficulties of summing higher order processes in pion multiple scattering theories, a new, systematic expansion for the interaction of a pion in nuclear matter is derived within the context of the Foldy-Walecka theory, incorporating nucleon-nucleon correlations and an idea of self-consistency. The first two orders in the expansion are evaluated as a function of the nonlocality range; the expansion appears to be rapidly converging, in contrast to expansion schemes previously examined. (Auth.)

Mean-field theory and self-consistent dynamo modeling

International Nuclear Information System (INIS)

Yoshizawa, Akira; Yokoi, Nobumitsu

2001-12-01

Mean-field theory of dynamo is discussed with emphasis on the statistical formulation of turbulence effects on the magnetohydrodynamic equations and the construction of a self-consistent dynamo model. The dynamo mechanism is sought in the combination of the turbulent residual-helicity and cross-helicity effects. On the basis of this mechanism, discussions are made on the generation of planetary magnetic fields such as geomagnetic field and sunspots and on the occurrence of flow by magnetic fields in planetary and fusion phenomena. (author)

Self-consistent atmosphere modeling with cloud formation for low-mass stars and exoplanets

Science.gov (United States)

Juncher, Diana; Jørgensen, Uffe G.; Helling, Christiane

2017-12-01

Context. Low-mass stars and extrasolar planets have ultra-cool atmospheres where a rich chemistry occurs and clouds form. The increasing amount of spectroscopic observations for extrasolar planets requires self-consistent model atmosphere simulations to consistently include the formation processes that determine cloud formation and their feedback onto the atmosphere. Aims: Our aim is to complement the MARCS model atmosphere suit with simulations applicable to low-mass stars and exoplanets in preparation of E-ELT, JWST, PLATO and other upcoming facilities. Methods: The MARCS code calculates stellar atmosphere models, providing self-consistent solutions of the radiative transfer and the atmospheric structure and chemistry. We combine MARCS with a kinetic model that describes cloud formation in ultra-cool atmospheres (seed formation, growth/evaporation, gravitational settling, convective mixing, element depletion). Results: We present a small grid of self-consistently calculated atmosphere models for Teff = 2000-3000 K with solar initial abundances and log (g) = 4.5. Cloud formation in stellar and sub-stellar atmospheres appears for Teff day-night energy transport and no temperature inversion.

Screening effects in a polyelectrolyte brush: self-consistent-field theory

NARCIS (Netherlands)

Zhulina, E.B.; Klein Wolterink, J.; Borisov, O.V.

2000-01-01

We have developed an analytical self-consistent-field (SCF) theory describing conformations of weakly charged polyelectrolyte chains tethered to the solid-liquid interface and immersed in a solution of low molecular weight salt. Depending on the density of grafting of the polyelectrolytes to the

Generation of static solutions of the self-consistent system of Einstein-Maxwell equations

International Nuclear Information System (INIS)

Anchikov, A.M.; Daishev, R.A.

1988-01-01

A theorem is proved, according to which to each solution of the Einstein equations with an arbitrary momentum-energy tensor in the right hand side there corresponds a static solution of the self-consistent system of Einstein-Maxwell equations. As a consequence of this theorem, a method is established of generating static solutions of the self-consistent system of Einstein-Maxwell equations with a charged grain as a source of vacuum solutions of the Einstein equations

A new self-consistent model for thermodynamics of binary solutions

Czech Academy of Sciences Publication Activity Database

Svoboda, Jiří; Shan, Y. V.; Fischer, F. D.

2015-01-01

Roč. 108, NOV (2015), s. 27-30 ISSN 1359-6462 R&D Projects: GA ČR(CZ) GA14-24252S Institutional support: RVO:68081723 Keywords : Thermodynamics * Analytical methods * CALPHAD * Phase diagram * Self-consistent model Subject RIV: BJ - Thermodynamics Impact factor: 3.305, year: 2015

Non-Born-Oppenheimer trajectories with self-consistent decay of mixing

International Nuclear Information System (INIS)

Zhu Chaoyuan; Jasper, Ahren W.; Truhlar, Donald G.

2004-01-01

A semiclassical trajectory method, called the self-consistent decay of mixing (SCDM) method, is presented for the treatment of electronically nonadiabatic dynamics. The SCDM method is a modification of the semiclassical Ehrenfest (SE) method (also called the semiclassical time-dependent self-consistent-field method) that solves the problem of unphysical mixed final states by including decay-of-mixing terms in the equations for the evolution of the electronic state populations. These terms generate a force, called the decoherent force (or dephasing force), that drives the electronic component of each trajectory toward a pure state. Results for several mixed quantum-classical methods, in particular the SCDM, SE, and natural-decay-of-mixing methods and several trajectory surface hopping methods, are compared to the results of accurate quantum mechanical calculations for 12 cases involving five different fully dimensional triatomic model systems. The SCDM method is found to be the most accurate of the methods tested. The method should be useful for the simulation of photochemical reactions

Justifying quasiparticle self-consistent schemes via gradient optimization in Baym-Kadanoff theory.

Science.gov (United States)

Ismail-Beigi, Sohrab

2017-09-27

The question of which non-interacting Green's function 'best' describes an interacting many-body electronic system is both of fundamental interest as well as of practical importance in describing electronic properties of materials in a realistic manner. Here, we study this question within the framework of Baym-Kadanoff theory, an approach where one locates the stationary point of a total energy functional of the one-particle Green's function in order to find the total ground-state energy as well as all one-particle properties such as the density matrix, chemical potential, or the quasiparticle energy spectrum and quasiparticle wave functions. For the case of the Klein functional, our basic finding is that minimizing the length of the gradient of the total energy functional over non-interacting Green's functions yields a set of self-consistent equations for quasiparticles that is identical to those of the quasiparticle self-consistent GW (QSGW) (van Schilfgaarde et al 2006 Phys. Rev. Lett. 96 226402-4) approach, thereby providing an a priori justification for such an approach to electronic structure calculations. In fact, this result is general, applies to any self-energy operator, and is not restricted to any particular approximation, e.g., the GW approximation for the self-energy. The approach also shows that, when working in the basis of quasiparticle states, solving the diagonal part of the self-consistent Dyson equation is of primary importance while the off-diagonals are of secondary importance, a common observation in the electronic structure literature of self-energy calculations. Finally, numerical tests and analytical arguments show that when the Dyson equation produces multiple quasiparticle solutions corresponding to a single non-interacting state, minimizing the length of the gradient translates into choosing the solution with largest quasiparticle weight.

Self-consistent generalized Langevin-equation theory for liquids of nonspherically interacting particles

Science.gov (United States)

Elizondo-Aguilera, L. F.; Zubieta Rico, P. F.; Ruiz-Estrada, H.; Alarcón-Waess, O.

2014-11-01

A self-consistent generalized Langevin-equation theory is proposed to describe the self- and collective dynamics of a liquid of linear Brownian particles. The equations of motion for the spherical harmonics projections of the collective and self-intermediate-scattering functions, Fl m ,l m(k ,t ) and Flm ,l m S(k ,t ) , are derived as a contraction of the description involving the stochastic equations of the corresponding tensorial one-particle density nl m(k ,t ) and the translational (α =T ) and rotational (α =R ) current densities jlm α(k ,t ) . Similar to the spherical case, these dynamic equations require as an external input the equilibrium structural properties of the system contained in the projections of the static structure factor, denoted by Sl m ,l m(k ) . Complementing these exact equations with simple (Vineyard-like) approximate relations for the collective and the self-memory functions we propose a closed self-consistent set of equations for the dynamic properties involved. In the long-time asymptotic limit, these equations become the so-called bifurcation equations, whose solutions (the nonergodicity parameters) can be written, extending the spherical case, in terms of one translational and one orientational scalar dynamic order parameter, γT and γR, which characterize the possible dynamical arrest transitions of the system. As a concrete illustrative application of this theory we determine the dynamic arrest diagram of the dipolar hard-sphere fluid. In qualitative agreement with mode coupling theory, the present self-consistent equations also predict three different regions in the state space spanned by the macroscopic control parameters η (volume fraction) and T* (scaled temperature): a region of fully ergodic states, a region of mixed states, in which the translational degrees of freedom become arrested while the orientational degrees of freedom remain ergodic, and a region of fully nonergodic states.

Self-consistent generalized Langevin-equation theory for liquids of nonspherically interacting particles.

Science.gov (United States)

Elizondo-Aguilera, L F; Zubieta Rico, P F; Ruiz-Estrada, H; Alarcón-Waess, O

2014-11-01

A self-consistent generalized Langevin-equation theory is proposed to describe the self- and collective dynamics of a liquid of linear Brownian particles. The equations of motion for the spherical harmonics projections of the collective and self-intermediate-scattering functions, F_{lm,lm}(k,t) and F_{lm,lm}^{S}(k,t), are derived as a contraction of the description involving the stochastic equations of the corresponding tensorial one-particle density n_{lm}(k,t) and the translational (α=T) and rotational (α=R) current densities j_{lm}^{α}(k,t). Similar to the spherical case, these dynamic equations require as an external input the equilibrium structural properties of the system contained in the projections of the static structure factor, denoted by S_{lm,lm}(k). Complementing these exact equations with simple (Vineyard-like) approximate relations for the collective and the self-memory functions we propose a closed self-consistent set of equations for the dynamic properties involved. In the long-time asymptotic limit, these equations become the so-called bifurcation equations, whose solutions (the nonergodicity parameters) can be written, extending the spherical case, in terms of one translational and one orientational scalar dynamic order parameter, γ_{T} and γ_{R}, which characterize the possible dynamical arrest transitions of the system. As a concrete illustrative application of this theory we determine the dynamic arrest diagram of the dipolar hard-sphere fluid. In qualitative agreement with mode coupling theory, the present self-consistent equations also predict three different regions in the state space spanned by the macroscopic control parameters η (volume fraction) and T* (scaled temperature): a region of fully ergodic states, a region of mixed states, in which the translational degrees of freedom become arrested while the orientational degrees of freedom remain ergodic, and a region of fully nonergodic states.

Renormalization of self-consistent approximation schemes at finite temperature. II. Applications to the sunset diagram

International Nuclear Information System (INIS)

Hees, Hendrik van; Knoll, Joern

2002-01-01

The theoretical concepts for the renormalization of self-consistent Dyson resummations, devised in the first paper of this series, are applied to first example cases of φ 4 theory. In addition to the tadpole (Hartree) approximation, as a novel part the numerical solutions are presented, which include the sunset self-energy diagram into the self-consistent scheme based on the Φ-derivable approximation or the two-particle irreducible effective action concept

Renormalization of self-consistent approximation schemes at finite temperature II: applications to the sunset diagram

International Nuclear Information System (INIS)

Hees, H. van; Knoll, J.

2001-01-01

The theoretical concepts for the renormalization of self-consistent Dyson resummations, deviced in the first paper of this series, are applied to first example cases for the φ 4 -theory. Besides the tadpole (Hartree) approximation as a novel part the numerical solutions are presented which includes the sunset self-energy diagram into the self-consistent scheme based on the Φ-derivable approximation or 2PI effective action concept. (orig.)

The q-deformed mKP hierarchy with self-consistent sources, Wronskian solutions and solitons

International Nuclear Information System (INIS)

Lin Runliang; Peng Hua; Manas, Manuel

2010-01-01

Based on the eigenfunction symmetry constraint of the q-deformed modified KP hierarchy, a q-deformed mKP hierarchy with self-consistent sources (q-mKPHSCSs) is constructed. The q-mKPHSCSs contain two types of q-deformed mKP equation with self-consistent sources. By the combination of the dressing method and the method of variation of constants, a generalized dressing approach is proposed to solve the q-deformed KP hierarchy with self-consistent sources (q-KPHSCSs). Using the gauge transformation between the q-KPHSCSs and the q-mKPHSCSs, the q-deformed Wronskian solutions for the q-KPHSCSs and the q-mKPHSCSs are obtained. The one-soliton solutions for the q-deformed KP (mKP) equation with a source are given explicitly.

Negative self-regard at work – Frustrating the need for self-enhancement and self-consistency

Directory of Open Access Journals (Sweden)

Marcus Credé

2003-10-01

Full Text Available A positive and consistent sense of self is a key requirement for psychological well-being. Thirteen South African police officers and five police psychologists were interviewed to investigate the prevalence of negative social feedback received by officers and the consequences of such feedback on their sense of self. Negative social feedback and perceived lack of support from police management, courts, and government were widely prevalent and were seen to impact strongly on police officers. Officers had a largely negative view of themselves, their organisation, and the social context in which they operated. They engaged in dysfunctional and self-destructive behaviour and experienced significant discrepancies between their work and non-work selves. Opsomming Aanduidings uit die literatuur is dat navorsing aangaande bevoegdheidsevaluering gebrekkig is aan ’n teoretiese ondertoon. Ondersoek word ingestel na die kognitiewe prosesse wat plaasvind gedurende beoordeling wat aanduidend kan wees van die hoë persentasie variansie tussen evalueerders. Die beginsels van vyf verskillende kognitiewe teorieë word bespreek om moontlike verklarings te ondersoek, naamlik kognitiewe keuse-, kognitiewe evaluering-, sosiaal kognitieweteorieë, meta-kognitiewe- en die nuwe paradigma- benaderings.

Self-consistent theory of finite Fermi systems and radii of nuclei

International Nuclear Information System (INIS)

Saperstein, E. E.; Tolokonnikov, S. V.

2011-01-01

Present-day self-consistent approaches in nuclear theory were analyzed from the point of view of describing distributions of nuclear densities. The generalized method of the energy density functional due to Fayans and his coauthors (this is the most successful version of the self-consistent theory of finite Fermi systems) was the first among the approaches under comparison. The second was the most successful version of the Skyrme-Hartree-Fock method with the HFB-17 functional due to Goriely and his coauthors. Charge radii of spherical nuclei were analyzed in detail. Several isotopic chains of deformed nuclei were also considered. Charge-density distributions ρ ch (r) were calculated for several spherical nuclei. They were compared with model-independent data extracted from an analysis of elastic electron scattering on nuclei.

Self-consistent study of local and nonlocal magnetoresistance in a YIG/Pt bilayer

Science.gov (United States)

Wang, Xi-guang; Zhou, Zhen-wei; Nie, Yao-zhuang; Xia, Qing-lin; Guo, Guang-hua

2018-03-01

We present a self-consistent study of the local spin Hall magnetoresistance (SMR) and nonlocal magnon-mediated magnetoresistance (MMR) in a heavy-metal/magnetic-insulator heterostructure at finite temperature. We find that the thermal fluctuation of magnetization significantly affects the SMR. It appears unidirectional with respect to the direction of electrical current (or magnetization). The unidirectionality of SMR originates from the asymmetry of creation or annihilation of thermal magnons induced by the spin Hall torque. Also, a self-consistent model can well describe the features of MMR.

Tunneling in a self-consistent dynamic image potential

International Nuclear Information System (INIS)

Rudberg, B.G.R.; Jonson, M.

1991-01-01

We have calculated the self-consistent effective potential for an electron tunneling through a square barrier while interacting with surface plasmons. This potential reduces to the classical image potential in the static limit. In the opposite limit, when the ''velocity'' of the tunneling electron is large, it reduces to the unperturbed square-barrier potential. For a wide variety of parameters the dynamic effects on the transmission coefficient T=|t 2 | can, for instance, be related to the Buettiker-Landauer traversal time for tunneling, given by τ BL =ℎ|d lnt/dV|

Self-consistent collisional-radiative model for hydrogen atoms: Atom–atom interaction and radiation transport

International Nuclear Information System (INIS)

Colonna, G.; Pietanza, L.D.; D’Ammando, G.

2012-01-01

Graphical abstract: Self-consistent coupling between radiation, state-to-state kinetics, electron kinetics and fluid dynamics. Highlight: ► A CR model of shock-wave in hydrogen plasma has been presented. ► All equations have been coupled self-consistently. ► Non-equilibrium electron and level distributions are obtained. ► The results show non-local effects and non-equilibrium radiation. - Abstract: A collisional-radiative model for hydrogen atom, coupled self-consistently with the Boltzmann equation for free electrons, has been applied to model a shock tube. The kinetic model has been completed considering atom–atom collisions and the vibrational kinetics of the ground state of hydrogen molecules. The atomic level kinetics has been also coupled with a radiative transport equation to determine the effective adsorption and emission coefficients and non-local energy transfer.

Integrable motion of curves in self-consistent potentials: Relation to spin systems and soliton equations

Energy Technology Data Exchange (ETDEWEB)

Myrzakulov, R.; Mamyrbekova, G.K.; Nugmanova, G.N.; Yesmakhanova, K.R. [Eurasian International Center for Theoretical Physics and Department of General and Theoretical Physics, Eurasian National University, Astana 010008 (Kazakhstan); Lakshmanan, M., E-mail: lakshman@cnld.bdu.ac.in [Centre for Nonlinear Dynamics, School of Physics, Bharathidasan University, Tiruchirapalli 620 024 (India)

2014-06-13

Motion of curves and surfaces in R{sup 3} lead to nonlinear evolution equations which are often integrable. They are also intimately connected to the dynamics of spin chains in the continuum limit and integrable soliton systems through geometric and gauge symmetric connections/equivalence. Here we point out the fact that a more general situation in which the curves evolve in the presence of additional self-consistent vector potentials can lead to interesting generalized spin systems with self-consistent potentials or soliton equations with self-consistent potentials. We obtain the general form of the evolution equations of underlying curves and report specific examples of generalized spin chains and soliton equations. These include principal chiral model and various Myrzakulov spin equations in (1+1) dimensions and their geometrically equivalent generalized nonlinear Schrödinger (NLS) family of equations, including Hirota–Maxwell–Bloch equations, all in the presence of self-consistent potential fields. The associated gauge equivalent Lax pairs are also presented to confirm their integrability. - Highlights: • Geometry of continuum spin chain with self-consistent potentials explored. • Mapping on moving space curves in R{sup 3} in the presence of potential fields carried out. • Equivalent generalized nonlinear Schrödinger (NLS) family of equations identified. • Integrability of identified nonlinear systems proved by deducing appropriate Lax pairs.

Self-consistent field theory of collisions: Orbital equations with asymptotic sources and self-averaged potentials

Energy Technology Data Exchange (ETDEWEB)

Hahn, Y.K., E-mail: ykhahn22@verizon.net

2014-12-15

The self-consistent field theory of collisions is formulated, incorporating the unique dynamics generated by the self-averaged potentials. The bound state Hartree–Fock approach is extended for the first time to scattering states, by properly resolving the principal difficulties of non-integrable continuum orbitals and imposing complex asymptotic conditions. The recently developed asymptotic source theory provides the natural theoretical basis, as the asymptotic conditions are completely transferred to the source terms and the new scattering function is made fullyintegrable. The scattering solutions can then be directly expressed in terms of bound state HF configurations, establishing the relationship between the bound and scattering state solutions. Alternatively, the integrable spin orbitals are generated by constructing the individual orbital equations that contain asymptotic sources and self-averaged potentials. However, the orbital energies are not determined by the equations, and a special channel energy fixing procedure is developed to secure the solutions. It is also shown that the variational construction of the orbital equations has intrinsic ambiguities that are generally associated with the self-consistent approach. On the other hand, when a small subset of open channels is included in the source term, the solutions are only partiallyintegrable, but the individual open channels can then be treated more simply by properly selecting the orbital energies. The configuration mixing and channel coupling are then necessary to complete the solution. The new theory improves the earlier continuum HF model. - Highlights: • First extension of HF to scattering states, with proper asymptotic conditions. • Orbital equations with asymptotic sources and integrable orbital solutions. • Construction of self-averaged potentials, and orbital energy fixing. • Channel coupling and configuration mixing, involving the new orbitals. • Critical evaluation of the

Isothermal Martensite Formation

DEFF Research Database (Denmark)

Villa, Matteo

Isothermal (i.e. time dependent) martensite formation in steel was first observed in the 40ies of the XXth century and is still treated as an anomaly in the description of martensite formation which is considered as a-thermal (i.e. independent of time). Recently, the clarification of the mechanism...... of lattice strains provided fundamental information on the state of stress in the material and clarified the role of the strain energy on martensite formation. Electron backscatter diffraction revealed that the microstructure of the material and the morphology of martensite were independent on the cooling...... leading to isothermal kinetics acquired new practical relevance because of the identification of isothermal martensite formation as the most likely process responsible for enhanced performances of sub-zero Celsius treated high carbon steel products. In the present work, different iron based alloys...

New Schemes for Positive Real Truncation

Directory of Open Access Journals (Sweden)

Kari Unneland

2007-07-01

Full Text Available Model reduction, based on balanced truncation, of stable and of positive real systems are considered. An overview over some of the already existing techniques are given: Lyapunov balancing and stochastic balancing, which includes Riccati balancing. A novel scheme for positive real balanced truncation is then proposed, which is a combination of the already existing Lyapunov balancing and Riccati balancing. Using Riccati balancing, the solution of two Riccati equations are needed to obtain positive real reduced order systems. For the suggested method, only one Lyapunov equation and one Riccati equation are solved in order to obtain positive real reduced order systems, which is less computationally demanding. Further it is shown, that in order to get positive real reduced order systems, only one Riccati equation needs to be solved. Finally, this is used to obtain positive real frequency weighted balanced truncation.

The self-consistent calculation of the edge states in bilayer quantum Hall bar

International Nuclear Information System (INIS)

Kavruk, A E; Orzturk, T; Orzturk, A; Atav, U; Yuksel, H

2011-01-01

In this study, we present the spatial distributions of the edge channels for each layer in bilayer quantum Hall bar geometry for a wide range of applied magnetic fields. For this purpose, we employ a self-consistent Thomas-Fermi-Poisson approach to obtain the electron density distributions and related screened potential distributions. In order to have a more realistic description of the system we solve three dimensional Poisson equation numerically in each iteration step to obtain self consistency in the Thomas-Fermi-Poisson approach instead of employing a 'frozen gate' approximation.

Self-consistent determination of quasiparticle properties in nuclear matter

International Nuclear Information System (INIS)

Oset, E.; Palanques-Mestre, A.

1981-01-01

The self-energy of nuclear matter is calculated by directing the attention to the energy and momentum dependent pieces which determine the quasiparticle properties. A microscopic approach is followed which starts from the boson exchange picture for the NN interaction, then the π-and p-mesons are shown to play a major role in the nucleon renormalization. The calculation is done self-consistently and the effective mass and pole strength determined as a function of the nuclear density and momentum. Particular emphasis is put on the non-static character of the interaction and its consequences. Finally a comparison is made with other calculations and with experimental results. The consequences of the nucleon renormalization in pion condensation are also examined with the result that the critical density is pushed up appreciably. (orig.)

Measuring a Truncated Disk in Aquila X-1

Science.gov (United States)

King, Ashley L.; Tomsick, John A.; Miller, Jon M.; Chenevez, Jerome; Barret, Didier; Boggs, Steven E.; Chakrabarty, Deepto; Christensen, Finn E.; Craig, William W.; Feurst, Felix;

Evolution of truncated moments of singlet parton distributions

International Nuclear Information System (INIS)

Forte, S.; Magnea, L.; Piccione, A.; Ridolfi, G.

2001-01-01

We define truncated Mellin moments of parton distributions by restricting the integration range over the Bjorken variable to the experimentally accessible subset x 0 ≤x≤1 of the allowed kinematic range 0≤x≤1. We derive the evolution equations satisfied by truncated moments in the general (singlet) case in terms of an infinite triangular matrix of anomalous dimensions which couple each truncated moment to all higher moments with orders differing by integers. We show that the evolution of any moment can be determined to arbitrarily good accuracy by truncating the system of coupled moments to a sufficiently large but finite size, and show how the equations can be solved in a way suitable for numerical applications. We discuss in detail the accuracy of the method in view of applications to precision phenomenology

Self-consistent hole motion and spin excitations in a quantum antiferromagnet

International Nuclear Information System (INIS)

Su, Z.B.; Yu, L.; Li, Y.M.; Lai, W.Y.

1989-12-01

A new quantum Bogoliubov-de Gennes (BdeG) formalism is developed to study the self-consistent motion of holes and spin excitations in a quantum antiferromagnet within the generalized t-J model. On the one hand, the effects of local distortion of spin configurations and the renormalization of the hole motion due to virtual excitations of the distorted spin background are treated on an equal footing to obtain the hole wave function and its spectrum, as well as the effective mass for a propagating hole. On the other hand, the change of the spin excitation spectrum and the spin correlations due to the presence of dynamical holes are studied within the same adiabatic approximation. The stability of the hole states with respect to such changes justifies the self-consistency of the proposed formalism. (author). 25 refs, 6 figs, 1 tab

Self-consistency of a heterogeneous continuum porous medium representation of a fractured medium

International Nuclear Information System (INIS)

Hoch, A.R.; Jackson, C.P.; Todman, S.

1998-01-01

For many of the rocks that are, or have been, under investigation as potential host rocks for a radioactive waste repository, groundwater flow is considered to take place predominantly through discontinuities such as fractures. Although models of networks of discrete features (DFN models) would be the most realistic models for such rocks, calculations on large length scales would not be computationally practicable. A possible approach would be to use heterogeneous continuum porous-medium (CPM) models in which each block has an effective permeability appropriate to represent the network of features within the block. In order to build confidence in this approach, it is necessary to demonstrate that the approach is self-consistent, in the sense that if the effective permeability on a large length scale is derived using the CPM model, the result is close to the value derived directly from the underlying network model. It is also desirable to demonstrate self-consistency for the use of stochastic heterogeneous CPM models that are built as follows. The correlation structure of the effective permeability on the scale of the blocks is inferred by analysis of the effective permeabilities obtained from the underlying DFN model. Then realizations of the effective permeability within the domain of interest are generated on the basis of the correlation structure, rather than being obtained directly from the underlying DFN model. A study of self-consistency is presented for two very different underlying DFN models: one based on the properties of the Borrowdale Volcanic Group at Sellafield, and one based on the properties of the granite at Aespoe in Sweden. It is shown that, in both cases, the use of heterogeneous CPM models based directly on the DFN model is self-consistent, provided that care is taken in the evaluation of the effective permeability for the DFN models. It is also shown that the use of stochastic heterogeneous CPM models based on the correlation structure of the

A self-consistency check for unitary propagation of Hawking quanta

Science.gov (United States)

Baker, Daniel; Kodwani, Darsh; Pen, Ue-Li; Yang, I.-Sheng

2017-11-01

The black hole information paradox presumes that quantum field theory in curved space-time can provide unitary propagation from a near-horizon mode to an asymptotic Hawking quantum. Instead of invoking conjectural quantum-gravity effects to modify such an assumption, we propose a self-consistency check. We establish an analogy to Feynman’s analysis of a double-slit experiment. Feynman showed that unitary propagation of the interfering particles, namely ignoring the entanglement with the double-slit, becomes an arbitrarily reliable assumption when the screen upon which the interference pattern is projected is infinitely far away. We argue for an analogous self-consistency check for quantum field theory in curved space-time. We apply it to the propagation of Hawking quanta and test whether ignoring the entanglement with the geometry also becomes arbitrarily reliable in the limit of a large black hole. We present curious results to suggest a negative answer, and we discuss how this loss of naive unitarity in QFT might be related to a solution of the paradox based on the soft-hair-memory effect.

Self-consistent modeling of amorphous silicon devices

International Nuclear Information System (INIS)

Hack, M.

1987-01-01

The authors developed a computer model to describe the steady-state behaviour of a range of amorphous silicon devices. It is based on the complete set of transport equations and takes into account the important role played by the continuous distribution of localized states in the mobility gap of amorphous silicon. Using one set of parameters they have been able to self-consistently simulate the current-voltage characteristics of p-i-n (or n-i-p) solar cells under illumination, the dark behaviour of field-effect transistors, p-i-n diodes and n-i-n diodes in both the ohmic and space charge limited regimes. This model also describes the steady-state photoconductivity of amorphous silicon, in particular, its dependence on temperature, doping and illumination intensity

Non linear self consistency of microtearing modes

International Nuclear Information System (INIS)

Garbet, X.; Mourgues, F.; Samain, A.

1987-01-01

The self consistency of a microtearing turbulence is studied in non linear regimes where the ergodicity of the flux lines determines the electron response. The current which sustains the magnetic perturbation via the Ampere law results from the combines action of the radial electric field in the frame where the island chains are static and of the thermal electron diamagnetism. Numerical calculations show that at usual values of β pol in Tokamaks the turbulence can create a diffusion coefficient of order ν th p 2 i where p i is the ion larmor radius and ν th the electron ion collision frequency. On the other hand, collisionless regimes involving special profiles of each mode near the resonant surface seem possible

Classical and Quantum Consistency of the DGP Model

CERN Document Server

Nicolis, A; Nicolis, Alberto; Rattazzi, Riccardo

2004-01-01

We study the Dvali-Gabadadze-Porrati model by the method of the boundary effective action. The truncation of this action to the bending mode \\pi consistently describes physics in a wide range of regimes both at the classical and at the quantum level. The Vainshtein effect, which restores agreement with precise tests of general relativity, follows straightforwardly. We give a simple and general proof of stability, i.e. absence of ghosts in the fluctuations, valid for most of the relevant cases, like for instance the spherical source in asymptotically flat space. However we confirm that around certain interesting self-accelerating cosmological solutions there is a ghost. We consider the issue of quantum corrections. Around flat space \\pi becomes strongly coupled below a macroscopic length of 1000 km, thus impairing the predictivity of the model. Indeed the tower of higher dimensional operators which is expected by a generic UV completion of the model limits predictivity at even larger length scales. We outline ...

Self-consistent-field calculations of proteinlike incorporations in polyelectrolyte complex micelles

NARCIS (Netherlands)

Lindhoud, S.; Cohen Stuart, M.A.; Norde, W.; Leermakers, F.A.M.

2009-01-01

Self-consistent field theory is applied to model the structure and stability of polyelectrolyte complex micelles with incorporated protein (molten globule) molecules in the core. The electrostatic interactions that drive the micelle formation are mimicked by nearest-neighbor interactions using

Modeling self-consistent multi-class dynamic traffic flow

Science.gov (United States)

Cho, Hsun-Jung; Lo, Shih-Ching

2002-09-01

In this study, we present a systematic self-consistent multiclass multilane traffic model derived from the vehicular Boltzmann equation and the traffic dispersion model. The multilane domain is considered as a two-dimensional space and the interaction among vehicles in the domain is described by a dispersion model. The reason we consider a multilane domain as a two-dimensional space is that the driving behavior of road users may not be restricted by lanes, especially motorcyclists. The dispersion model, which is a nonlinear Poisson equation, is derived from the car-following theory and the equilibrium assumption. Under the concept that all kinds of users share the finite section, the density is distributed on a road by the dispersion model. In addition, the dynamic evolution of the traffic flow is determined by the systematic gas-kinetic model derived from the Boltzmann equation. Multiplying Boltzmann equation by the zeroth, first- and second-order moment functions, integrating both side of the equation and using chain rules, we can derive continuity, motion and variance equation, respectively. However, the second-order moment function, which is the square of the individual velocity, is employed by previous researches does not have physical meaning in traffic flow. Although the second-order expansion results in the velocity variance equation, additional terms may be generated. The velocity variance equation we propose is derived from multiplying Boltzmann equation by the individual velocity variance. It modifies the previous model and presents a new gas-kinetic traffic flow model. By coupling the gas-kinetic model and the dispersion model, a self-consistent system is presented.

Self-consistent Ginzburg-Landau theory for transport currents in superconductors

DEFF Research Database (Denmark)

Ögren, Magnus; Sørensen, Mads Peter; Pedersen, Niels Falsig

2012-01-01

We elaborate on boundary conditions for Ginzburg-Landau (GL) theory in the case of external currents. We implement a self-consistent theory within the finite element method (FEM) and present numerical results for a two-dimensional rectangular geometry. We emphasize that our approach can in princi...... in principle also be used for general geometries in three-dimensional superconductors....

Self-consistent model calculations of the ordered S-matrix and the cylinder correction

International Nuclear Information System (INIS)

Millan, J.

1977-11-01

The multiperipheral ordered bootstrap of Rosenzweig and Veneziano is studied by using dual triple Regge couplings exhibiting the required threshold behavior. In the interval -0.5 less than or equal to t less than or equal to 0.8 GeV 2 self-consistent reggeon couplings and propagators are obtained for values of Regge slopes and intercepts consistent with the physical values for the leading natural-parity Regge trajectories. Cylinder effects on planar pole positions and couplings are calculated. By use of an unsymmetrical planar π--rho reggeon loop model, self-consistent solutions are obtained for the unnatural-parity mesons in the interval -0.5 less than or equal to t less than or equal to 0.6 GeV 2 . The effects of other Regge poles being neglected, the model gives a value of the π--eta splitting consistent with experiment. 24 figures, 1 table, 25 references

Two-particle self-consistent approach to unconventional superconductivity

Energy Technology Data Exchange (ETDEWEB)

Otsuki, Junya [Department of Physics, Tohoku University, Sendai (Japan); Theoretische Physik III, Zentrum fuer Elektronische Korrelationen und Magnetismus, Universitaet Augsburg (Germany)

2013-07-01

A non-perturbative approach to unconventional superconductivity is developed based on the idea of the two-particle self-consistent (TPSC) theory. An exact sum-rule which the momentum-dependent pairing susceptibility satisfies is derived. Effective pairing interactions between quasiparticles are determined so that an approximate susceptibility should fulfill this sum-rule, in which fluctuations belonging to different symmetries mix at finite momentum. The mixing leads to a suppression of the d{sub x{sup 2}-y{sup 2}} pairing close to the half-filling, resulting in a maximum of T{sub c} away from half-filling.

Poisson solvers for self-consistent multi-particle simulations

International Nuclear Information System (INIS)

Qiang, J; Paret, S

2014-01-01

Self-consistent multi-particle simulation plays an important role in studying beam-beam effects and space charge effects in high-intensity beams. The Poisson equation has to be solved at each time-step based on the particle density distribution in the multi-particle simulation. In this paper, we review a number of numerical methods that can be used to solve the Poisson equation efficiently. The computational complexity of those numerical methods will be O(N log(N)) or O(N) instead of O(N2), where N is the total number of grid points used to solve the Poisson equation

Spontaneous symmetry breaking and self-consistent equations for the free-energy

International Nuclear Information System (INIS)

Lovesey, S.W.

1980-03-01

A variational procedure for the free-energy is used to derive self-consistent equations that allow for spontaneous symmetry breaking. For an N-component phi 4 -model the equations are identical to those obtained by summing all loops to order 1/N. (author)

Communication: A difference density picture for the self-consistent field ansatz

Energy Technology Data Exchange (ETDEWEB)

Parrish, Robert M.; Liu, Fang; Martínez, Todd J., E-mail: toddjmartinez@gmail.com [Department of Chemistry and the PULSE Institute, Stanford University, Stanford, California 94305 (United States); SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States)

2016-04-07

We formulate self-consistent field (SCF) theory in terms of an interaction picture where the working variable is the difference density matrix between the true system and a corresponding superposition of atomic densities. As the difference density matrix directly represents the electronic deformations inherent in chemical bonding, this “difference self-consistent field (dSCF)” picture provides a number of significant conceptual and computational advantages. We show that this allows for a stable and efficient dSCF iterative procedure with wholly single-precision Coulomb and exchange matrix builds. We also show that the dSCF iterative procedure can be performed with aggressive screening of the pair space. These approximations are tested and found to be accurate for systems with up to 1860 atoms and >10 000 basis functions, providing for immediate overall speedups of up to 70% in the heavily optimized TERACHEM SCF implementation.

Communication: A difference density picture for the self-consistent field ansatz

International Nuclear Information System (INIS)

Parrish, Robert M.; Liu, Fang; Martínez, Todd J.

2016-01-01

We formulate self-consistent field (SCF) theory in terms of an interaction picture where the working variable is the difference density matrix between the true system and a corresponding superposition of atomic densities. As the difference density matrix directly represents the electronic deformations inherent in chemical bonding, this “difference self-consistent field (dSCF)” picture provides a number of significant conceptual and computational advantages. We show that this allows for a stable and efficient dSCF iterative procedure with wholly single-precision Coulomb and exchange matrix builds. We also show that the dSCF iterative procedure can be performed with aggressive screening of the pair space. These approximations are tested and found to be accurate for systems with up to 1860 atoms and >10 000 basis functions, providing for immediate overall speedups of up to 70% in the heavily optimized TERACHEM SCF implementation.

Communication: A difference density picture for the self-consistent field ansatz

Science.gov (United States)

Parrish, Robert M.; Liu, Fang; Martínez, Todd J.

2016-04-01

We formulate self-consistent field (SCF) theory in terms of an interaction picture where the working variable is the difference density matrix between the true system and a corresponding superposition of atomic densities. As the difference density matrix directly represents the electronic deformations inherent in chemical bonding, this "difference self-consistent field (dSCF)" picture provides a number of significant conceptual and computational advantages. We show that this allows for a stable and efficient dSCF iterative procedure with wholly single-precision Coulomb and exchange matrix builds. We also show that the dSCF iterative procedure can be performed with aggressive screening of the pair space. These approximations are tested and found to be accurate for systems with up to 1860 atoms and >10 000 basis functions, providing for immediate overall speedups of up to 70% in the heavily optimized TeraChem SCF implementation.

Isothermal and non-isothermal conditions of isotope separation by chemical exchange method

International Nuclear Information System (INIS)

Khoroshilov, A.V.; Andreev, B.M.; Katalnikov, S.G.

1992-01-01

The published data about the effect of temperature on thermodynamic and mass transfer parameters of isotope separation by the chemical exchange method were used to examine the influence of iso- and non-isothermal conditions on the effectiveness of the separation process. It has been shown that simultaneous fulfillment of several optimization criteria is impossible in optimization of the isothermal process. If the limitation that temperature must be constant in the whole range of concentrational changes for an isolated isotope is removed, then it is possible to solve the problem of optimization with simultaneous fulfillment of several optimization criteria. When the separation process is carried out with non-isothermal conditions, that is, in temperature cascade, then the maximum concentration change takes place at every theoretical separation plate, and whole cascade is characterised by maximum throughput, minimum height and volume, and minimum cost for the stream reflux. From the results of our study, it was concluded that in the optimum temperature cascade, the cost of production of unity quantity of isotope can be decreased at least by a factor of two as compared with the optimal isothermal version of the separation process. (author)

Self-consistent GW0 results for the electron gas: Fixed screened potential W0 within the random-phase approximation

International Nuclear Information System (INIS)

von Barth, U.; Holm, B.

1996-01-01

With the aim of properly understanding the basis for and the utility of many-body perturbation theory as applied to extended metallic systems, we have calculated the electronic self-energy of the homogeneous electron gas within the GW approximation. The calculation has been carried out in a self-consistent way; i.e., the one-electron Green function obtained from Dyson close-quote s equation is the same as that used to calculate the self-energy. The self-consistency is restricted in the sense that the screened interaction W is kept fixed and equal to that of the random-phase approximation for the gas. We have found that the final results are marginally affected by the broadening of the quasiparticles, and that their self-consistent energies are still close to their free-electron counterparts as they are in non-self-consistent calculations. The reduction in strength of the quasiparticles and the development of satellite structure (plasmons) gives, however, a markedly smaller dynamical self-energy leading to, e.g., a smaller reduction in the quasiparticle strength as compared to non-self-consistent results. The relatively bad description of plasmon structure within the non-self-consistent GW approximation is marginally improved. A first attempt at including W in the self-consistency cycle leads to an even broader and structureless satellite spectrum in disagreement with experiment. copyright 1996 The American Physical Society

Mean fields and self consistent normal ordering of lattice spin and gauge field theories

International Nuclear Information System (INIS)

Ruehl, W.

1986-01-01

Classical Heisenberg spin models on lattices possess mean field theories that are well defined real field theories on finite lattices. These mean field theories can be self consistently normal ordered. This leads to a considerable improvement over standard mean field theory. This concept is carried over to lattice gauge theories. We construct first an appropriate real mean field theory. The equations determining the Gaussian kernel necessary for self-consistent normal ordering of this mean field theory are derived. (orig.)

Data and performance profiles applying an adaptive truncation criterion, within linesearch-based truncated Newton methods, in large scale nonconvex optimization

Directory of Open Access Journals (Sweden)

Andrea Caliciotti

2018-04-01

Full Text Available In this paper, we report data and experiments related to the research article entitled “An adaptive truncation criterion, for linesearch-based truncated Newton methods in large scale nonconvex optimization” by Caliciotti et al. [1]. In particular, in Caliciotti et al. [1], large scale unconstrained optimization problems are considered by applying linesearch-based truncated Newton methods. In this framework, a key point is the reduction of the number of inner iterations needed, at each outer iteration, to approximately solving the Newton equation. A novel adaptive truncation criterion is introduced in Caliciotti et al. [1] to this aim. Here, we report the details concerning numerical experiences over a commonly used test set, namely CUTEst (Gould et al., 2015 [2]. Moreover, comparisons are reported in terms of performance profiles (Dolan and Moré, 2002 [3], adopting different parameters settings. Finally, our linesearch-based scheme is compared with a renowned trust region method, namely TRON (Lin and Moré, 1999 [4].

Isothermal and non-isothermal cure of a tri-functional epoxy resin (TGAP): A stochastic TMDSC study

International Nuclear Information System (INIS)

Hutchinson, John M.; Shiravand, Fatemeh; Calventus, Yolanda; Fraga, Iria

2012-01-01

Highlights: ► First evaluation of T g of tri-functional epoxy resin TGAP by DSC. ► Clearly shows advantages of TOPEM for isothermal and non-isothermal cure analysis. ► Evidence of highly non-linear enthalpy relaxation in partially cured TGAP system. - Abstract: The isothermal cure of a highly reactive tri-functional epoxy resin, tri-glycidyl para-amino phenol (TGAP), with diamino diphenyl sulphone (DDS), at two different cure temperatures T c has been studied by both conventional differential scanning calorimetry (DSC) and by a stochastic temperature modulated DSC technique, TOPEM. From a series of isothermal cure experiments for increasing cure times, the glass transition temperature T g as a function of isothermal cure time is determined by conventional DSC from a second (non-isothermal) scan, and the vitrification time t v is obtained as the time at which T g = T c . In parallel, TOPEM experiments at the same T c lead directly to the determination of t v from the sigmoidal change in the quasi-static heat capacity. It is not possible to identify the glass transition temperature of the fully cured system, T g∞ , in a third scan by conventional DSC. In contrast, with TOPEM a second (non-isothermal) scan at 2 K/min after the isothermal cure gives rise to three separate transitions: devitrification of the partially cured and vitrified material; almost immediate vitrification as the T g of the system again rises; finally another devitrification, at a temperature approximating closely to T g∞ . Thus with TOPEM it is possible to obtain a calorimetric measure of the glass transition temperature of this fully cured system.

Self-consistent field theory based molecular dynamics with linear system-size scaling

Energy Technology Data Exchange (ETDEWEB)

Richters, Dorothee [Institute of Mathematics and Center for Computational Sciences, Johannes Gutenberg University Mainz, Staudinger Weg 9, D-55128 Mainz (Germany); Kühne, Thomas D., E-mail: kuehne@uni-mainz.de [Institute of Physical Chemistry and Center for Computational Sciences, Johannes Gutenberg University Mainz, Staudinger Weg 7, D-55128 Mainz (Germany); Technical and Macromolecular Chemistry, University of Paderborn, Warburger Str. 100, D-33098 Paderborn (Germany)

2014-04-07

We present an improved field-theoretic approach to the grand-canonical potential suitable for linear scaling molecular dynamics simulations using forces from self-consistent electronic structure calculations. It is based on an exact decomposition of the grand canonical potential for independent fermions and does neither rely on the ability to localize the orbitals nor that the Hamilton operator is well-conditioned. Hence, this scheme enables highly accurate all-electron linear scaling calculations even for metallic systems. The inherent energy drift of Born-Oppenheimer molecular dynamics simulations, arising from an incomplete convergence of the self-consistent field cycle, is circumvented by means of a properly modified Langevin equation. The predictive power of the present approach is illustrated using the example of liquid methane under extreme conditions.

Conditional truncated plurigaussian simulation; Simulacao plurigaussiana truncada com condicionamento

Energy Technology Data Exchange (ETDEWEB)

Simon, Vitor Hugo

1997-12-01

The goal of this work was a development of an algorithm for the Truncated Plurigaussian Stochastic Simulation and its validation in a complex geologic model. The reservoir data comes from Aux Vases Zone at Rural Hill Field in Illinois, USA, and from the 2D geological interpretation, described by WEIMER et al. (1982), three sets of samples, with different grid densities ware taken. These sets were used to condition the simulation and to refine the estimates of the non-stationary matrix of facies proportions, used to truncate the gaussian random functions (RF). The Truncated Plurigaussian Model is an extension of the Truncated Gaussian Model (TG). In this new model its possible to use several facies with different spatial structures, associated with the simplicity of TG. The geological interpretation, used as a validation model, was chosen because it shows a set of NW/SE elongated tidal channels cutting the NE/SW shoreline deposits interleaved by impermeable facies. These characteristics of spatial structures of sedimentary facies served to evaluate the simulation model. Two independent gaussian RF were used, as well as an 'erosive model' as the truncation strategy. Also, non-conditional simulations were proceeded, using linearly combined gaussian RF with varying correlation coefficients. It was analyzed the influence of some parameters like: number of gaussian RF,correlation coefficient, truncations strategy, in the outcome of simulation, and also the physical meaning of these parameters under a geological point of view. It was showed, step by step, using an example, the theoretical model, and how to construct an algorithm to simulate with the Truncated Plurigaussian Model. The conclusion of this work was that even with a plain algorithm of the Conditional Truncated Plurigaussian and a complex geological model it's possible to obtain a usefulness product. (author)

Nonlinear and self-consistent treatment of ECRH

Energy Technology Data Exchange (ETDEWEB)

Tsironis, C.; Vlahos, L.

2005-07-01

A self-consistent formulation for the nonlinear interaction of electromagnetic waves with relativistic magnetized electrons is applied for the description of the ECRH. In general, electron-cyclotron absorption is the result of resonances between the cyclotron harmonics and the Doppler-shifted waver frequency. The resonant interaction results to an intense wave-particle energy exchange and an electron acceleration, and for that reason it is widely applied in fusion experiments for plasma heating and current drive. The linear theory, for the wave absorption, as well as the quasilinear theory for the electron distribution function, are the most frequently-used tools for the study of wave-particle interactions. However, in many cases the validity of these theories is violated, namely cases where nonlinear effects, like, e. g. particle trapping in the wave field, are dominant in the particle phase-space. Our model consists of electrons streaming and gyrating in a tokamak plasma slab, which is finite in the directions perpendicular to the main magnetic field. The particles interact with an electromagnetic electron-cyclotron wave of the ordinary (O-) or the extraordinary (X-) mode. A set of nonlinear and relativistic equations is derived, which take into account the effects of the charged particle motions on the wave. These consist of the equations of motion for the plasma electrons in the slab, as well as the wave equation in terms of the vector potential. The effect of the electron motions on the temporal evolution of the wave is reflected in the current density source term. (Author)

Nonlinear and self-consistent treatment of ECRH

International Nuclear Information System (INIS)

Tsironis, C.; Vlahos, L.

2005-01-01

A self-consistent formulation for the nonlinear interaction of electromagnetic waves with relativistic magnetized electrons is applied for the description of the ECRH. In general, electron-cyclotron absorption is the result of resonances between the cyclotron harmonics and the Doppler-shifted waver frequency. The resonant interaction results to an intense wave-particle energy exchange and an electron acceleration, and for that reason it is widely applied in fusion experiments for plasma heating and current drive. The linear theory, for the wave absorption, as well as the quasilinear theory for the electron distribution function, are the most frequently-used tools for the study of wave-particle interactions. However, in many cases the validity of these theories is violated, namely cases where nonlinear effects, like, e. g. particle trapping in the wave field, are dominant in the particle phase-space. Our model consists of electrons streaming and gyrating in a tokamak plasma slab, which is finite in the directions perpendicular to the main magnetic field. The particles interact with an electromagnetic electron-cyclotron wave of the ordinary (O-) or the extraordinary (X-) mode. A set of nonlinear and relativistic equations is derived, which take into account the effects of the charged particle motions on the wave. These consist of the equations of motion for the plasma electrons in the slab, as well as the wave equation in terms of the vector potential. The effect of the electron motions on the temporal evolution of the wave is reflected in the current density source term. (Author)

Exciton spectrum of surface-corrugated quantum wells: the adiabatic self-consistent approach

International Nuclear Information System (INIS)

Atenco A, N.; Perez R, F.; Makarov, N.M.

2005-01-01

A theory for calculating the relaxation frequency ν and the shift δ ω of exciton resonances in quantum wells with finite potential barriers and adiabatic surface disorder is developed. The adiabaticity implies that the correlation length R C for the well width fluctuations is much larger than the exciton radius a 0 (R C >> a 0 ). Our theory is based on the self-consistent Green's function method, and therefore takes into account the inherent action of the exciton scattering on itself. The self-consistent approach is shown to describe quantitatively the sharp exciton resonance. It also gives the qualitatively correct resonance picture for the transition to the classical limit, as well as within the domain of the classical limit itself. We present and analyze results for h h-exciton in a GaAs quantum well with Al 0.3 Ga 0.7 As barriers. It is established that the self-consistency and finite height of potential barriers significantly influence on the line-shape of exciton resonances, and make the values of ν and δ ω be quite realistic. In particular, the relaxation frequency ν for the ground-state resonance has a broad, almost symmetric maximum near the resonance frequency ω 0 , while the surface-induced resonance shift δ ω vanishes near ω 0 , and has different signs on the sides of the exciton resonance. (Author) 43 refs., 4 figs

Truncation in diffraction pattern analysis. Pt. 1

International Nuclear Information System (INIS)

Delhez, R.; Keijser, T.H. de; Mittemeijer, E.J.; Langford, J.I.

1986-01-01

An evaluation of the concept of a line profile is provoked by truncation of the range of intensity measurement in practice. The measured truncated line profile can be considered either as part of the total intensity distribution which peaks at or near the reciprocal-lattice points (approach 1), or as part of a component line profile which is confined to a single reciprocal-lattice point (approach 2). Some false conceptions in line-profile analysis can then be avoided and recipes can be developed for the extrapolation of the tails of the truncated line profile. Fourier analysis of line profiles, according to the first approach, implies a Fourier series development of the total intensity distribution defined within [l - 1/2, l + 1/2] (l indicates the node considered in reciprocal space); the second approach implies a Fourier transformation of the component line profile defined within [ - ∞, + ∞]. Exact descriptions of size broadening are provided by both approaches, whereas combined size and strain broadening can only be evaluated adequately within the first approach. Straightforward methods are given for obtaining truncation-corrected values for the average crystallite size. (orig.)

Self-consistent field theory of polymer-ionic molecule complexation

OpenAIRE

Nakamura, Issei; Shi, An-Chang

2010-01-01

A self-consistent field theory is developed for polymers that are capable of binding small ionic molecules (adsorbates). The polymer-ionic molecule association is described by Ising-like binding variables, C_(i)^(a)(kΔ)(= 0 or 1), whose average determines the number of adsorbed molecules, nBI. Polymer gelation can occur through polymer-ionic molecule complexation in our model. For polymer-polymer cross-links through the ionic molecules, three types of solutions for nBI are obtained, depending...

Self-consistent equilibria in cylindrical reversed-field pinch

International Nuclear Information System (INIS)

Lo Surdo, C.; Paccagnella, R.; Guo, S.

1995-03-01

The object of this work is to study the self-consistent magnetofluidstatic equilibria of a 2-region (plasma + gas) reversed-field pinch (RFP) in cylindrical approximation (namely, with vanishing inverse aspect ratio). Differently from what happens in a tokamak, in a RFP a significant part of the plasma current is driven by a dynamo electric field (DEF), in its turn mainly due to plasma turbulence. So, it is worked out a reasonable mathematical model of the above self-consistent equilibria under the following main points it has been: a) to the lowest order, and according to a standard ansatz, the turbulent DEF say ε t , is expressed as a homogeneous transform of the magnetic field B of degree 1, ε t =(α) (B), with α≡a given 2-nd rank tensor, homogeneous of degree 0 in B and generally depending on the plasma state; b) ε t does not explicitly appear in the plasma energy balance, as it were produced by a Maxwell demon able of extract the corresponding Joule power from the plasma. In particular, it is showed that, if both α and the resistivity tensor η are isotropic and constant, the magnetic field is force-free with abnormality equal to αη 0 /η, in the limit of vanishing β; that is, the well-known J.B. Taylor'result is recovered, in this particular conditions, starting from ideas quite different from the usual ones (minimization of total magnetic energy under constrained total elicity). Finally, the general problem is solved numerically under circular (besides cylindrical) symmetry, for simplicity neglecting the existence of gas region (i.e., assuming the plasma in direct contact with the external wall)

Isothermal transitions of a thermosetting system

Science.gov (United States)

Gillham, J. K.; Benci, J. A.; Noshay, A.

1974-01-01

A study of the curing reactions of a cycloaliphatic epoxy resin/anhydride system by torsional braid analysis showed the existence of two critical isothermal temperatures - namely, the maximum glass transition temperature of the thermoset system and the glass transition temperature of the material at its gel point. Two rheologically active kinetic transitions occur during isothermal cure which correspond to gelation and vitrification. Three types of isothermal behavior occur. Methods for determining the time to gel and the time to vitrify, and also the two above-mentioned critical isothermal temperatures, have been developed. The time to gel obeyed the Arrhenius relationship, whereas the time to vitrify passed through a minimum. Application of these results to thermosetting systems in general is discussed in terms of the influence of molecular structure on the values of the critical isothermal temperatures.

Self-consistent simulation studies of periodically focused intense charged-particle beams

International Nuclear Information System (INIS)

Chen, C.; Jameson, R.A.

1995-01-01

A self-consistent two-dimensional model is used to investigate intense charged-particle beam propagation through a periodic solenoidal focusing channel, particularly in the regime in which there is a mismatch between the beam and the focusing channel. The present self-consistent studies confirm that mismatched beams exhibit nonlinear resonances and chaotic behavior in the envelope evolution, as predicted by an earlier envelope analysis [C. Chen and R. C. Davidson, Phys. Rev. Lett. 72, 2195 (1994)]. Transient effects due to emittance growth are studied, and halo formation is investigated. The halo size is estimated. The halo characteristics for a periodic focusing channel are found to be qualitatively the same as those for a uniform focusing channel. A threshold condition is obtained numerically for halo formation in mismatched beams in a uniform focusing channel, which indicates that relative envelope mismatch must be kept well below 20% to prevent space-charge-dominated beams from developing halos

Room temperature isotherms for Mo and Ni

International Nuclear Information System (INIS)

Masse, J.L.

1986-11-01

Isotherms at room temperature for Mo and Ni are proposed. They are of three types: BIRCH, KEANE and BORN-MIE. The adjustable constants appearing in these isotherms have been determined from experimental quantities at zero pressure. An evaluation of the limit of (δB T /δP) T as P #-> # ∞, where B T is the isothermal bulk modulus, has been also used. These three isotherms obtained for Mo and Ni are compared with isotherms derived from shock-wave data according to the PRIETO's model. There is a good agreement between these and these derived from shock-wave data. The three isotherms proposed for Mo and Ni can be considered as valid until pressures of several B To , where B To is the bulk modulus B T at P = o [fr

Self-Consistent Sources Extensions of Modified Differential-Difference KP Equation

Science.gov (United States)

Gegenhasi; Li, Ya-Qian; Zhang, Duo-Duo

2018-04-01

In this paper, we investigate a modified differential-difference KP equation which is shown to have a continuum limit into the mKP equation. It is also shown that the solution of the modified differential-difference KP equation is related to the solution of the differential-difference KP equation through a Miura transformation. We first present the Grammian solution to the modified differential-difference KP equation, and then produce a coupled modified differential-difference KP system by applying the source generation procedure. The explicit N-soliton solution of the resulting coupled modified differential-difference system is expressed in compact forms by using the Grammian determinant and Casorati determinant. We also construct and solve another form of the self-consistent sources extension of the modified differential-difference KP equation, which constitutes a Bäcklund transformation for the differential-difference KP equation with self-consistent sources. Supported by the National Natural Science Foundation of China under Grant Nos. 11601247 and 11605096, the Natural Science Foundation of Inner Mongolia Autonomous Region under Grant Nos. 2016MS0115 and 2015MS0116 and the Innovation Fund Programme of Inner Mongolia University No. 20161115

Self-accelerating parabolic cylinder waves in 1-D

Energy Technology Data Exchange (ETDEWEB)

Yuce, C., E-mail: cyuce@anadolu.edu.tr

2016-11-25

Highlights: • We find a new class of self-accelerating waves. • We show that parabolic cylinder waves self-accelerates in a parabolic potential. • We discuss that truncated parabolic cylinder waves propagates large distance without almost being non-diffracted in free space. - Abstract: We introduce a new self-accelerating wave packet solution of the Schrodinger equation in one dimension. We obtain an exact analytical parabolic cylinder wave for the inverted harmonic potential. We show that truncated parabolic cylinder waves exhibits their accelerating feature.

Self-consistent electronic-structure calculations for interface geometries

International Nuclear Information System (INIS)

Sowa, E.C.; Gonis, A.; MacLaren, J.M.; Zhang, X.G.

1992-01-01

This paper describes a technique for computing self-consistent electronic structures and total energies of planar defects, such as interfaces, which are embedded in an otherwise perfect crystal. As in the Layer Korringa-Kohn-Rostoker approach, the solid is treated as a set of coupled layers of atoms, using Bloch's theorem to take advantage of the two-dimensional periodicity of the individual layers. The layers are coupled using the techniques of the Real-Space Multiple-Scattering Theory, avoiding artificial slab or supercell boundary conditions. A total-energy calculation on a Cu crystal, which has been split apart at a (111) plane, is used to illustrate the method

Truncation Depth Rule-of-Thumb for Convolutional Codes

Science.gov (United States)

Moision, Bruce

2009-01-01

In this innovation, it is shown that a commonly used rule of thumb (that the truncation depth of a convolutional code should be five times the memory length, m, of the code) is accurate only for rate 1/2 codes. In fact, the truncation depth should be 2.5 m/(1 - r), where r is the code rate. The accuracy of this new rule is demonstrated by tabulating the distance properties of a large set of known codes. This new rule was derived by bounding the losses due to truncation as a function of the code rate. With regard to particular codes, a good indicator of the required truncation depth is the path length at which all paths that diverge from a particular path have accumulated the minimum distance of the code. It is shown that the new rule of thumb provides an accurate prediction of this depth for codes of varying rates.

Tanh-travelling wave solutions, truncated Painleve expansion and reduction of Bullough-Dodd equation to a quadrature in magnetohydrodynamic equilibrium

International Nuclear Information System (INIS)

Ibrahim, R.S.

2003-01-01

The equations of magnetohydrodynamic (MHD) equilibria for a plasma in gravitational field are investigated. For equilibria with one ignorable spatial coordinate, the MHD equations are reduced to a single nonlinear elliptic equation for the magnetic potential u-tilde, known as the Grad-Shafranov equation. Specifying the arbitrary functions in this equation, the Bullough-Dodd equation can be obtained. The truncated Painleve expansion and reduction of the partial differential equation to a quadrature problem (RQ method) are described and applied to obtain the travelling wave solutions of the Bullough-Dodd equation for the case of isothermal magnetostatic atmosphere, in which the current density J is proportional to the exponentially of the magnetic flux and moreover falls off exponentially with distance vertical to the base, with an 'e-folding' distance equal to the gravitational scale height

Isothermal and non-isothermal cure of a tri-functional epoxy resin (TGAP): a stochastic TMDSC study

OpenAIRE

Hutchinson, John M.; Shiravand, Fatemeh; Calventus Solé, Yolanda; Fraga Rivas, Iria

2012-01-01

The isothermal cure of a highly reactive tri-functional epoxy resin, tri-glycidyl para-amino phenol (TGAP), with diamino diphenyl sulphone (DDS), at two different cure temperatures Tc has been studied by both conventional differential scanning calorimetry (DSC) and by a stochastic temperature modulated DSC technique, TOPEM. From a series of isothermal cure experiments for increasing cure times, the glass transition temperature Tg as a function of isothermal cure time is determined by co...

Non-isothermal cure and exfoliation of tri-functional epoxy-clay nanocomposites

Directory of Open Access Journals (Sweden)

F. Shiravand

2015-08-01

Full Text Available The non-isothermal cure kinetics of polymer silicate layered nanocomposites based on a tri-functional epoxy resin has been investigated by differential scanning calorimetry. From an analysis of the kinetics as a function of the clay content, it can be concluded that the non-isothermal cure reaction can be considered to consist of four different processes: the reaction of epoxy groups with the diamine curing agent; an intra-gallery homopolymerisation reaction which occurs concurrently with the epoxy-amine reaction; and two extra-gallery homopolymerisation reactions, catalysed by the onium ion of the organically modified clay and by the tertiary amines resulting from the epoxy-amine reaction. The final nanostructure displays a similar quality of exfoliation as that observed for the isothermal cure of the same nanocomposite system. This implies that the intra-gallery reaction, which is responsible for the exfoliation, is not significantly inhibited by the extra-gallery epoxy-amine cross-linking reaction.

On the hydrodynamic limit of self-consistent field equations

International Nuclear Information System (INIS)

Pauli, H.C.

1980-01-01

As an approximation to the nuclear many-body problem, the hydrodynamical limit of self-consistent field equations is worked out and applied to the treatment of vibrational and rotational motion. Its validity is coupled to the value of a smallness parameter, behaving as 20Asup(-2/3) with the number of nucleons. For finite nuclei, this number is not small enough as compared to 1, and indeed one observes a discrepancy of roughly a factor of 5 between the hydrodynamic frequencies and the relevant experimental numbers. (orig.)

Multiconfigurational self-consistent reaction field theory for nonequilibrium solvation

DEFF Research Database (Denmark)

Mikkelsen, Kurt V.; Cesar, Amary; Ågren, Hans

1995-01-01

electronic structure whereas the inertial polarization vector is not necessarily in equilibrium with the actual electronic structure. The electronic structure of the compound is described by a correlated electronic wave function - a multiconfigurational self-consistent field (MCSCF) wave function. This wave......, open-shell, excited, and transition states. We demonstrate the theory by computing solvatochromatic shifts in optical/UV spectra of some small molecules and electron ionization and electron detachment energies of the benzene molecule. It is shown that the dependency of the solvent induced affinity...

A self-consistent nuclear energy supply system

International Nuclear Information System (INIS)

Fujii-e, Y.; Morita, T.; Kawakami, H.; Arie, K.; Suzuki, M.; Iida, M.; Yamazaki, H.

1992-01-01

A self-consistent nuclear energy supply system (SCNESS) is investigated for a Fast Reactor. SCNESS is proposed as a future stable energy supplier with no harmful influence on humans or environment for the ultimate goal of nuclear energy development. SCNESS should be inherently safe, be able to breed fissionable material, and transmute long-lived radioactive nuclides (i.e., minor actinides and long-lived fission products). The relationship between these characteristics and the spatial assignment of excess neutrons (v-1) for each characteristic are analyzed. The analysis shows that excess neutrons play an intrinsic role in realizing SCNESS. The reactor concept of SCNESS is investigated by considering utilization of excess neutrons. Results show that a small-size axially double-layered annular core with metal fuel is a choice candidate for SCNESS. SCNESS is concluded feasible. (author). 4 refs., 9 figs

Wigner distribution function of circularly truncated light beams

NARCIS (Netherlands)

Bastiaans, M.J.; Nijhawan, O.P.; Gupta, A.K.; Musla, A.K.; Singh, Kehar

1998-01-01

Truncating a light beam is expressed as a convolution of its Wigner distribution function and the WDF of the truncating aperture. The WDF of a circular aperture is derived and an approximate expression - which is exact in the space and the spatial-frequency origin and whose integral over the spatial

Consistency Over Flattery: Self-Verification Processes Revealed in Implicit and Behavioral Responses to Feedback

OpenAIRE

Ayduk, O; Gyurak, A; Akinola, M; Mendes, WB

2013-01-01

Negative social feedback is often a source of distress. However, self-verification theory provides the counterintuitive explanation that negative feedback leads to less distress when it is consistent with chronic self-views. Drawing from this work, the present study examined the impact of receiving self-verifying feedback on outcomes largely neglected in prior research: implicit responses (i.e., physiological reactivity, facial expressions) that are difficult to consciously regulate and downs...

Exciton spectrum of surface-corrugated quantum wells: the adiabatic self-consistent approach

Energy Technology Data Exchange (ETDEWEB)

Atenco A, N.; Perez R, F. [lnstituto de Fisica, Universidad Autonoma de Puebla, A.P. J-48, 72570 Puebla (Mexico); Makarov, N.M. [lnstituto de Ciencias, Universidad Autonoma de Puebla, Priv. 17 Norte No 3417, Col. San Miguel Hueyotlipan, 72050 Puebla (Mexico)

2005-07-01

A theory for calculating the relaxation frequency {nu} and the shift {delta} {omega} of exciton resonances in quantum wells with finite potential barriers and adiabatic surface disorder is developed. The adiabaticity implies that the correlation length R{sub C} for the well width fluctuations is much larger than the exciton radius a{sub 0} (R{sub C} >> a{sub 0}). Our theory is based on the self-consistent Green's function method, and therefore takes into account the inherent action of the exciton scattering on itself. The self-consistent approach is shown to describe quantitatively the sharp exciton resonance. It also gives the qualitatively correct resonance picture for the transition to the classical limit, as well as within the domain of the classical limit itself. We present and analyze results for h h-exciton in a GaAs quantum well with Al{sub 0.3} Ga{sub 0.7}As barriers. It is established that the self-consistency and finite height of potential barriers significantly influence on the line-shape of exciton resonances, and make the values of {nu} and {delta} {omega} be quite realistic. In particular, the relaxation frequency {nu} for the ground-state resonance has a broad, almost symmetric maximum near the resonance frequency {omega}{sub 0}, while the surface-induced resonance shift {delta} {omega} vanishes near {omega}{sub 0}, and has different signs on the sides of the exciton resonance. (Author) 43 refs., 4 figs.

The effect of truncation on very small cardiac SPECT camera systems

International Nuclear Information System (INIS)

Rohmer, Damien; Eisner, Robert L.; Gullberg, Grant T.

2006-01-01

Background: The limited transaxial field-of-view (FOV) of a very small cardiac SPECT camera system causes view-dependent truncation of the projection of structures exterior to, but near the heart. Basic tomographic principles suggest that the reconstruction of non-attenuated truncated data gives a distortion-free image in the interior of the truncated region, but the DC term of the Fourier spectrum of the reconstructed image is incorrect, meaning that the intensity scale of the reconstruction is inaccurate. The purpose of this study was to characterize the reconstructed image artifacts from truncated data, and to quantify their effects on the measurement of tracer uptake in the myocardial. Particular attention was given to instances where the heart wall is close to hot structures (structures of high activity uptake).Methods: The MCAT phantom was used to simulate a 2D slice of the heart region. Truncated and non-truncated projections were formed both with and without attenuation. The reconstructions were analyzed for artifacts in the myocardium caused by truncation, and for the effect that attenuation has relative to increasing those artifacts. Results: The inaccuracy due to truncation is primarily caused by an incorrect DC component. For visualizing the left ventricular wall, this error is not worse than the effect of attenuation. The addition of a small hot bowel-like structure near the left ventricle causes few changes in counts on the wall. Larger artifacts due to the truncation are located at the boundary of the truncation and can be eliminated by sinogram interpolation. Finally,algebraic reconstruction methods are shown to give better reconstruction results than an analytical filtered back-projection reconstruction algorithm. Conclusion: Small inaccuracies in reconstructed images from small FOV camera systems should have little effect on clinical interpretation. However, changes in the degree of inaccuracy in counts from slice to slice are due to changes in

Simulations of Turbulence in Tokamak Edge and Effects of Self-Consistent Zonal Flows

Science.gov (United States)

Cohen, Bruce; Umansky, Maxim

2013-10-01

Progress is reported on simulations of electromagnetic drift-resistive ballooning turbulence in the tokamak edge. This extends previous work to include self-consistent zonal flows and their effects. The previous work addressed simulation of L-mode tokamak edge turbulence using the turbulence code BOUT that solves Braginskii-based plasma fluid equations in tokamak edge domain. The calculations use realistic single-null geometry and plasma parameters of the DIII-D tokamak and produce fluctuation amplitudes, fluctuation spectra, and particle and thermal fluxes that compare favorably to experimental data. In the effect of sheared ExB poloidal rotation is included with an imposed static radial electric field fitted to experimental data. In the new work here we include the radial electric field self-consistently driven by the microturbulence, which contributes to the sheared ExB poloidal rotation (zonal flow generation). We present simulations with/without zonal flows for both cylindrical geometry, as in the UCLA Large Plasma Device, and for the DIII-D tokamak L-mode cases in to quantify the influence of self-consistent zonal flows on the microturbulence and the concomitant transport. This work was performed under the auspices of the U.S. Department of Energy under contract DE-AC52-07NA27344 at the Lawrence Livermore National Laboratory.

Online self-report questionnaire on computer work-related exposure (OSCWE): validity and internal consistency.

Science.gov (United States)

Mekhora, Keerin; Jalayondeja, Wattana; Jalayondeja, Chutima; Bhuanantanondh, Petcharatana; Dusadiisariyavong, Asadang; Upiriyasakul, Rujiret; Anuraktam, Khajornyod

2014-07-01

To develop an online, self-report questionnaire on computer work-related exposure (OSCWE) and to determine the internal consistency, face and content validity of the questionnaire. The online, self-report questionnaire was developed to determine the risk factors related to musculoskeletal disorders in computer users. It comprised five domains: personal, work-related, work environment, physical health and psychosocial factors. The questionnaire's content was validated by an occupational medical doctor and three physical therapy lecturers involved in ergonomic teaching. Twenty-five lay people examined the feasibility of computer-administered and the user-friendly language. The item correlation in each domain was analyzed by the internal consistency (Cronbach's alpha; alpha). The content of the questionnaire was considered congruent with the testing purposes. Eight hundred and thirty-five computer users at the PTT Exploration and Production Public Company Limited registered to the online self-report questionnaire. The internal consistency of the five domains was: personal (alpha = 0.58), work-related (alpha = 0.348), work environment (alpha = 0.72), physical health (alpha = 0.68) and psychosocial factor (alpha = 0.93). The findings suggested that the OSCWE had acceptable internal consistency for work environment and psychosocial factors. The OSCWE is available to use in population-based survey research among computer office workers.

A self-consistent mean field theory for diffusion in alloys

International Nuclear Information System (INIS)

Nastar, M.; Barbe, V.

2007-01-01

Starting from a microscopic model of the atomic transport via vacancies and interstitials in alloys, a self-consistent mean field (SCMF) kinetic theory yields the phenomenological coefficients L ij . In this theory, kinetic correlations are accounted for through a set of effective interactions within a non-equilibrium distribution function of the system. The introduction of a master equation describing the evolution with time of the distribution function and its moments leads to general self-consistent kinetic equations. The L ij of a face centered cubic alloy are calculated using the kinetic equations of Nastar (M. Nastar, Philos. Mag., 2005, 85, 3767, ref. 1) derived from a microscopic broken bond model of the vacancy jump frequency. A first approximation leads to an analytical expression of the L ij and a second approximation to a better agreement with the Monte Carlo simulations. A change of sign of the L ij is studied as a function of the microscopic parameters of the jump frequency. The L ij of a cubic centered alloy obtained for the complex diffusion mechanism of the dumbbell configuration of the interstitial are used to study the effect of an on-site rotation of the dumbbell on the transport. (authors)

Integrating the Toda Lattice with Self-Consistent Source via Inverse Scattering Method

International Nuclear Information System (INIS)

Urazboev, Gayrat

2012-01-01

In this work, there is shown that the solutions of Toda lattice with self-consistent source can be found by the inverse scattering method for the discrete Sturm-Liuville operator. For the considered problem the one-soliton solution is obtained.

Flexible scheme to truncate the hierarchy of pure states.

Science.gov (United States)

Zhang, P-P; Bentley, C D B; Eisfeld, A

2018-04-07

The hierarchy of pure states (HOPS) is a wavefunction-based method that can be used for numerically modeling open quantum systems. Formally, HOPS recovers the exact system dynamics for an infinite depth of the hierarchy. However, truncation of the hierarchy is required to numerically implement HOPS. We want to choose a "good" truncation method, where by "good" we mean that it is numerically feasible to check convergence of the results. For the truncation approximation used in previous applications of HOPS, convergence checks are numerically challenging. In this work, we demonstrate the application of the "n-particle approximation" to HOPS. We also introduce a new approximation, which we call the "n-mode approximation." We then explore the convergence of these truncation approximations with respect to the number of equations required in the hierarchy in two exemplary problems: absorption and energy transfer of molecular aggregates.

Flexible scheme to truncate the hierarchy of pure states

Science.gov (United States)

Zhang, P.-P.; Bentley, C. D. B.; Eisfeld, A.

2018-04-01

The hierarchy of pure states (HOPS) is a wavefunction-based method that can be used for numerically modeling open quantum systems. Formally, HOPS recovers the exact system dynamics for an infinite depth of the hierarchy. However, truncation of the hierarchy is required to numerically implement HOPS. We want to choose a "good" truncation method, where by "good" we mean that it is numerically feasible to check convergence of the results. For the truncation approximation used in previous applications of HOPS, convergence checks are numerically challenging. In this work, we demonstrate the application of the "n-particle approximation" to HOPS. We also introduce a new approximation, which we call the "n-mode approximation." We then explore the convergence of these truncation approximations with respect to the number of equations required in the hierarchy in two exemplary problems: absorption and energy transfer of molecular aggregates.

Charge neutralization as the major factor for the assembly of nucleocapsid-like particles from C-terminal truncated hepatitis C virus core protein

Directory of Open Access Journals (Sweden)

Theo Luiz Ferraz de Souza

2016-11-01

Full Text Available Background Hepatitis C virus (HCV core protein, in addition to its structural role to form the nucleocapsid assembly, plays a critical role in HCV pathogenesis by interfering in several cellular processes, including microRNA and mRNA homeostasis. The C-terminal truncated HCV core protein (C124 is intrinsically unstructured in solution and is able to interact with unspecific nucleic acids, in the micromolar range, and to assemble into nucleocapsid-like particles (NLPs in vitro. The specificity and propensity of C124 to the assembly and its implications on HCV pathogenesis are not well understood. Methods Spectroscopic techniques, transmission electron microscopy and calorimetry were used to better understand the propensity of C124 to fold or to multimerize into NLPs when subjected to different conditions or in the presence of unspecific nucleic acids of equivalent size to cellular microRNAs. Results The structural analysis indicated that C124 has low propensity to self-folding. On the other hand, for the first time, we show that C124, in the absence of nucleic acids, multimerizes into empty NLPs when subjected to a pH close to its isoelectric point (pH ≈ 12, indicating that assembly is mainly driven by charge neutralization. Isothermal calorimetry data showed that the assembly of NLPs promoted by nucleic acids is enthalpy driven. Additionally, data obtained from fluorescence correlation spectroscopy show that C124, in nanomolar range, was able to interact and to sequester a large number of short unspecific nucleic acids into NLPs. Discussion Together, our data showed that the charge neutralization is the major factor for the nucleocapsid-like particles assembly from C-terminal truncated HCV core protein. This finding suggests that HCV core protein may physically interact with unspecific cellular polyanions, which may correspond to microRNAs and mRNAs in a host cell infected by HCV, triggering their confinement into infectious particles.

Comparison of self-consistent calculations of the static polarizability of atoms and molecules

International Nuclear Information System (INIS)

Moullet, I.; Martins, J.L.

1990-01-01

The static dipole polarizabilities and other ground-state properties of H, H 2 , He, Na, and Na 2 are calculated using five different self-consistent schemes: Hartree--Fock, local spin density approximation, Hartree--Fock plus local density correlation, self-interaction-corrected local spin density approximation, and Hartree--Fock plus self-interaction-corrected local density correlation. The inclusion of the self-interaction corrected local spin density approximation in the Hartree--Fock method improves dramatically the calculated dissociation energies of molecules but has a small effect on the calculated polarizabilities. Correcting the local spin density calculations for self-interaction effects improves the calculated polarizability in the cases where the local spin density results are mediocre, and has only a small effect in the cases where the local spin density values are in reasonable agreement with experiment

Self-Consistent Model of Magnetospheric Electric Field, Ring Current, Plasmasphere, and Electromagnetic Ion Cyclotron Waves: Initial Results

Science.gov (United States)

Gamayunov, K. V.; Khazanov, G. V.; Liemohn, M. W.; Fok, M.-C.; Ridley, A. J.

2009-01-01

Further development of our self-consistent model of interacting ring current (RC) ions and electromagnetic ion cyclotron (EMIC) waves is presented. This model incorporates large scale magnetosphere-ionosphere coupling and treats self-consistently not only EMIC waves and RC ions, but also the magnetospheric electric field, RC, and plasmasphere. Initial simulations indicate that the region beyond geostationary orbit should be included in the simulation of the magnetosphere-ionosphere coupling. Additionally, a self-consistent description, based on first principles, of the ionospheric conductance is required. These initial simulations further show that in order to model the EMIC wave distribution and wave spectral properties accurately, the plasmasphere should also be simulated self-consistently, since its fine structure requires as much care as that of the RC. Finally, an effect of the finite time needed to reestablish a new potential pattern throughout the ionosphere and to communicate between the ionosphere and the equatorial magnetosphere cannot be ignored.

Self-consistent gyrokinetic modeling of neoclassical and turbulent impurity transport

OpenAIRE

Estève , D. ,; Sarazin , Y.; Garbet , X.; Grandgirard , V.; Breton , S. ,; Donnel , P. ,; Asahi , Y. ,; Bourdelle , C.; Dif-Pradalier , G; Ehrlacher , C.; Emeriau , C.; Ghendrih , Ph; Gillot , C.; Latu , G.; Passeron , C.

2018-01-01

International audience; Trace impurity transport is studied with the flux-driven gyrokinetic GYSELA code [V. Grandgirard et al., Comp. Phys. Commun. 207, 35 (2016)]. A reduced and linearized multi-species collision operator has been recently implemented, so that both neoclassical and turbulent transport channels can be treated self-consistently on an equal footing. In the Pfirsch-Schlüter regime likely relevant for tungsten, the standard expression of the neoclassical impurity flux is shown t...

Truncated predictor feedback for time-delay systems

CERN Document Server

Zhou, Bin

2014-01-01

This book provides a systematic approach to the design of predictor based controllers for (time-varying) linear systems with either (time-varying) input or state delays. Differently from those traditional predictor based controllers, which are infinite-dimensional static feedback laws and may cause difficulties in their practical implementation, this book develops a truncated predictor feedback (TPF) which involves only finite dimensional static state feedback. Features and topics: A novel approach referred to as truncated predictor feedback for the stabilization of (time-varying) time-delay systems in both the continuous-time setting and the discrete-time setting is built systematically Semi-global and global stabilization problems of linear time-delay systems subject to either magnitude saturation or energy constraints are solved in a systematic manner Both stabilization of a single system and consensus of a group of systems (multi-agent systems) are treated in a unified manner by applying the truncated pre...

Modeling of Experimental Adsorption Isotherm Data

Directory of Open Access Journals (Sweden)

Xunjun Chen

2015-01-01

Full Text Available Adsorption is considered to be one of the most effective technologies widely used in global environmental protection areas. Modeling of experimental adsorption isotherm data is an essential way for predicting the mechanisms of adsorption, which will lead to an improvement in the area of adsorption science. In this paper, we employed three isotherm models, namely: Langmuir, Freundlich, and Dubinin-Radushkevich to correlate four sets of experimental adsorption isotherm data, which were obtained by batch tests in lab. The linearized and non-linearized isotherm models were compared and discussed. In order to determine the best fit isotherm model, the correlation coefficient (r2 and standard errors (S.E. for each parameter were used to evaluate the data. The modeling results showed that non-linear Langmuir model could fit the data better than others, with relatively higher r2 values and smaller S.E. The linear Langmuir model had the highest value of r2, however, the maximum adsorption capacities estimated from linear Langmuir model were deviated from the experimental data.

Detecting and correcting for publication bias in meta-analysis - A truncated normal distribution approach.

Science.gov (United States)

Zhu, Qiaohao; Carriere, K C

2016-01-01

Publication bias can significantly limit the validity of meta-analysis when trying to draw conclusion about a research question from independent studies. Most research on detection and correction for publication bias in meta-analysis focus mainly on funnel plot-based methodologies or selection models. In this paper, we formulate publication bias as a truncated distribution problem, and propose new parametric solutions. We develop methodologies of estimating the underlying overall effect size and the severity of publication bias. We distinguish the two major situations, in which publication bias may be induced by: (1) small effect size or (2) large p-value. We consider both fixed and random effects models, and derive estimators for the overall mean and the truncation proportion. These estimators will be obtained using maximum likelihood estimation and method of moments under fixed- and random-effects models, respectively. We carried out extensive simulation studies to evaluate the performance of our methodology, and to compare with the non-parametric Trim and Fill method based on funnel plot. We find that our methods based on truncated normal distribution perform consistently well, both in detecting and correcting publication bias under various situations.

Electro-optical study of nanoscale Al-Si-truncated conical photodetector with subwavelength aperture

Science.gov (United States)

Karelits, Matityahu; Mandelbaum, Yaakov; Chelly, Avraham; Karsenty, Avi

2017-10-01

A type of silicon photodiode has been designed and simulated to probe the optical near field and detect evanescent waves. These waves convey subwavelength resolution. This photodiode consists of a truncated conical shaped, silicon Schottky diode having a subwavelength aperture of 150 nm. Electrical and electro-optical simulations have been conducted. These results are promising toward the fabrication of a new generation of photodetector devices.

Self-consistent mean-field models for nuclear structure

International Nuclear Information System (INIS)

Bender, Michael; Heenen, Paul-Henri; Reinhard, Paul-Gerhard

2003-01-01

The authors review the present status of self-consistent mean-field (SCMF) models for describing nuclear structure and low-energy dynamics. These models are presented as effective energy-density functionals. The three most widely used variants of SCMF's based on a Skyrme energy functional, a Gogny force, and a relativistic mean-field Lagrangian are considered side by side. The crucial role of the treatment of pairing correlations is pointed out in each case. The authors discuss other related nuclear structure models and present several extensions beyond the mean-field model which are currently used. Phenomenological adjustment of the model parameters is discussed in detail. The performance quality of the SCMF model is demonstrated for a broad range of typical applications

The self-consistent dynamic pole tide in global oceans

Science.gov (United States)

Dickman, S. R.

1985-01-01

The dynamic pole tide is characterized in a self-consistent manner by means of introducing a single nondifferential matrix equation compatible with the Liouville equation, modelling the ocean as global and of uniform depth. The deviations of the theory from the realistic ocean, associated with the nonglobality of the latter, are also given consideration, with an inference that in realistic oceans long-period modes of resonances would be increasingly likely to exist. The analysis of the nature of the pole tide and its effects on the Chandler wobble indicate that departures of the pole tide from the equilibrium may indeed be minimal.

Using Trait-State Models to Evaluate the Longitudinal Consistency of Global Self-Esteem From Adolescence to Adulthood

Science.gov (United States)

Donnellan, M. Brent; Kenny, David A.; Trzesniewski, Kali H.; Lucas, Richard E.; Conger, Rand D.

2012-01-01

The present research used a latent variable trait-state model to evaluate the longitudinal consistency of self-esteem during the transition from adolescence to adulthood. Analyses were based on ten administrations of the Rosenberg Self-Esteem scale (Rosenberg, 1965) spanning the ages of approximately 13 to 32 for a sample of 451 participants. Results indicated that a completely stable trait factor and an autoregressive trait factor accounted for the majority of the variance in latent self-esteem assessments, whereas state factors accounted for about 16% of the variance in repeated assessments of latent self-esteem. The stability of individual differences in self-esteem increased with age consistent with the cumulative continuity principle of personality development. PMID:23180899

Using Trait-State Models to Evaluate the Longitudinal Consistency of Global Self-Esteem From Adolescence to Adulthood.

Science.gov (United States)

Donnellan, M Brent; Kenny, David A; Trzesniewski, Kali H; Lucas, Richard E; Conger, Rand D

2012-12-01

The present research used a latent variable trait-state model to evaluate the longitudinal consistency of self-esteem during the transition from adolescence to adulthood. Analyses were based on ten administrations of the Rosenberg Self-Esteem scale (Rosenberg, 1965) spanning the ages of approximately 13 to 32 for a sample of 451 participants. Results indicated that a completely stable trait factor and an autoregressive trait factor accounted for the majority of the variance in latent self-esteem assessments, whereas state factors accounted for about 16% of the variance in repeated assessments of latent self-esteem. The stability of individual differences in self-esteem increased with age consistent with the cumulative continuity principle of personality development.

Lopsidedness of Self-consistent Galaxies Caused by the External Field Effect of Clusters

Energy Technology Data Exchange (ETDEWEB)

Wu, Xufen [CAS Key Laboratory for Research in Galaxies and Cosmology, Department of Astronomy, University of Science and Technology of China, Hefei, 230026 (China); Wang, Yougang [Key Laboratory of Computational Astrophysics, National Astronomical Observatories, Chinese Academy of Sciences, Beijing, 100012 (China); Feix, Martin [CNRS, UMR 7095 and UPMC, Institut d’Astrophysique de Paris, 98 bis Boulevard Arago, F-75014 Paris (France); Zhao, HongSheng, E-mail: xufenwu@ustc.edu.cn [School of Physics and Astronomy, University of St Andrews, North Haugh, Fife, KY16 9SS (United Kingdom)

2017-08-01

Adopting Schwarzschild’s orbit-superposition technique, we construct a series of self-consistent galaxy models, embedded in the external field of galaxy clusters in the framework of Milgrom’s MOdified Newtonian Dynamics (MOND). These models represent relatively massive ellipticals with a Hernquist radial profile at various distances from the cluster center. Using N -body simulations, we perform a first analysis of these models and their evolution. We find that self-gravitating axisymmetric density models, even under a weak external field, lose their symmetry by instability and generally evolve to triaxial configurations. A kinematic analysis suggests that the instability originates from both box and nonclassified orbits with low angular momentum. We also consider a self-consistent isolated system that is then placed in a strong external field and allowed to evolve freely. This model, just like the corresponding equilibrium model in the same external field, eventually settles to a triaxial equilibrium as well, but has a higher velocity radial anisotropy and is rounder. The presence of an external field in the MOND universe generically predicts some lopsidedness of galaxy shapes.

Lopsidedness of Self-consistent Galaxies Caused by the External Field Effect of Clusters

Science.gov (United States)

Wu, Xufen; Wang, Yougang; Feix, Martin; Zhao, HongSheng

2017-08-01

Adopting Schwarzschild’s orbit-superposition technique, we construct a series of self-consistent galaxy models, embedded in the external field of galaxy clusters in the framework of Milgrom’s MOdified Newtonian Dynamics (MOND). These models represent relatively massive ellipticals with a Hernquist radial profile at various distances from the cluster center. Using N-body simulations, we perform a first analysis of these models and their evolution. We find that self-gravitating axisymmetric density models, even under a weak external field, lose their symmetry by instability and generally evolve to triaxial configurations. A kinematic analysis suggests that the instability originates from both box and nonclassified orbits with low angular momentum. We also consider a self-consistent isolated system that is then placed in a strong external field and allowed to evolve freely. This model, just like the corresponding equilibrium model in the same external field, eventually settles to a triaxial equilibrium as well, but has a higher velocity radial anisotropy and is rounder. The presence of an external field in the MOND universe generically predicts some lopsidedness of galaxy shapes.

Self-consistent DFT +U method for real-space time-dependent density functional theory calculations

Science.gov (United States)

Tancogne-Dejean, Nicolas; Oliveira, Micael J. T.; Rubio, Angel

2017-12-01

We implemented various DFT+U schemes, including the Agapito, Curtarolo, and Buongiorno Nardelli functional (ACBN0) self-consistent density-functional version of the DFT +U method [Phys. Rev. X 5, 011006 (2015), 10.1103/PhysRevX.5.011006] within the massively parallel real-space time-dependent density functional theory (TDDFT) code octopus. We further extended the method to the case of the calculation of response functions with real-time TDDFT+U and to the description of noncollinear spin systems. The implementation is tested by investigating the ground-state and optical properties of various transition-metal oxides, bulk topological insulators, and molecules. Our results are found to be in good agreement with previously published results for both the electronic band structure and structural properties. The self-consistent calculated values of U and J are also in good agreement with the values commonly used in the literature. We found that the time-dependent extension of the self-consistent DFT+U method yields improved optical properties when compared to the empirical TDDFT+U scheme. This work thus opens a different theoretical framework to address the nonequilibrium properties of correlated systems.

New results to BDD truncation method for efficient top event probability calculation

International Nuclear Information System (INIS)

Mo, Yuchang; Zhong, Farong; Zhao, Xiangfu; Yang, Quansheng; Cui, Gang

2012-01-01

A Binary Decision Diagram (BDD) is a graph-based data structure that calculates an exact top event probability (TEP). It has been a very difficult task to develop an efficient BDD algorithm that can solve a large problem since its memory consumption is very high. Recently, in order to solve a large reliability problem within limited computational resources, Jung presented an efficient method to maintain a small BDD size by a BDD truncation during a BDD calculation. In this paper, it is first identified that Jung's BDD truncation algorithm can be improved for a more practical use. Then, a more efficient truncation algorithm is proposed in this paper, which can generate truncated BDD with smaller size and approximate TEP with smaller truncation error. Empirical results showed this new algorithm uses slightly less running time and slightly more storage usage than Jung's algorithm. It was also found, that designing a truncation algorithm with ideal features for every possible fault tree is very difficult, if not impossible. The so-called ideal features of this paper would be that with the decrease of truncation limits, the size of truncated BDD converges to the size of exact BDD, but should never be larger than exact BDD.

Adolescent Self-Esteem: Differences by Race/Ethnicity, Gender, and Age.

Science.gov (United States)

Bachman, Jerald G; O'Malley, Patrick M; Freedman-Doan, Peter; Trzesniewski, Kali H; Donnellan, M Brent

2011-01-01

Large-scale representative surveys of 8th-, 10th-, and 12th-grade students in the United States show high self-esteem scores for all groups. African-American students score highest, Whites score slightly higher than Hispanics, and Asian Americans score lowest. Males score slightly higher than females. Multivariate controls for grades and college plans actually heighten these race/ethnic/gender differences. A truncated scoring method, designed to counter race/ethnic differences in extreme response style, reduced but did not eliminate the subgroup differences. Age differences in self-esteem are modest, with 12th graders reporting the highest scores. The findings are highly consistent across 18 annual surveys from 1991 through 2008, and self-esteem scores show little overall change during that period.

Adolescent Self-Esteem: Differences by Race/Ethnicity, Gender, and Age

Science.gov (United States)

Bachman, Jerald G.; O’Malley, Patrick M.; Freedman-Doan, Peter; Trzesniewski, Kali H.; Donnellan, M. Brent

2012-01-01

Large-scale representative surveys of 8th-, 10th-, and 12th-grade students in the United States show high self-esteem scores for all groups. African-American students score highest, Whites score slightly higher than Hispanics, and Asian Americans score lowest. Males score slightly higher than females. Multivariate controls for grades and college plans actually heighten these race/ethnic/gender differences. A truncated scoring method, designed to counter race/ethnic differences in extreme response style, reduced but did not eliminate the subgroup differences. Age differences in self-esteem are modest, with 12th graders reporting the highest scores. The findings are highly consistent across 18 annual surveys from 1991 through 2008, and self-esteem scores show little overall change during that period. PMID:22279425

Self-consistent collective coordinate method for large amplitude collective motions

International Nuclear Information System (INIS)

Sakata, F.; Hashimoto, Y.; Marumori, T.; Une, T.

1982-01-01

A recent development of the self-consistent collective coordinate method is described. The self-consistent collective coordinate method was proposed on the basis of the fundamental principle called the invariance principle of the Schroedinger equation. If this is formulated within a framework of the time dependent Hartree Fock (TDHF) theory, a classical version of the theory is obtained. A quantum version of the theory is deduced by formulating it within a framework of the unitary transformation method with auxiliary bosons. In this report, the discussion is concentrated on a relation between the classical theory and the quantum theory, and an applicability of the classical theory. The aim of the classical theory is to extract a maximally decoupled collective subspace out of a huge dimensional 1p - 1h parameter space introduced by the TDHF theory. An intimate similarity between the classical theory and a full quantum boson expansion method (BEM) was clarified. Discussion was concentrated to a simple Lipkin model. Then a relation between the BEM and the unitary transformation method with auxiliary bosons was discussed. It became clear that the quantum version of the theory had a strong relation to the BEM, and that the BEM was nothing but a quantum analogue of the present classical theory. The present theory was compared with the full TDHF calculation by using a simple model. (Kato, T.)

Electron confinement in quantum nanostructures: Self-consistent Poisson-Schroedinger theory

International Nuclear Information System (INIS)

Luscombe, J.H.; Bouchard, A.M.; Luban, M.

1992-01-01

We compute the self-consistent electron states and confining potential, V(r,T), for laterally confined cylindrical quantum wires at a temperature T from a numerical solution of the coupled Poisson and Schroedinger (PS) equations. Finite-temperature effects are included in the electron density function, n(r,T), via the single-particle density matrix in the grand-canonical ensemble using the self-consistent bound states. We compare our results for a GaAs quantum wire with those obtained previously [J. H. Luscombe and M. Luban, Appl. Phys. Lett. 57, 61 (1990)] from a finite-temperature Thomas-Fermi (TF) approximation. We find that the TF results agree well with those of the more realistic, but also more computationally intensive PS theory, except for low temperatures or for cases where the quantum wire is almost, but not totally, depleted due to a combination of either small geometry, surface boundary conditions, or low doping concentrations. In the latter situations, the number of subbands that are populated is relatively small, and both n(r,T) and V(r,T) exhibit Friedel-type oscillations. Otherwise the TF theory, which is based on free-particle states, is remarkably accurate. We also present results for the partial electron density functions associated with the angular momentum quantum numbers, and discuss their role in populating the quantum wire

Adiabatic and isothermal resistivities

International Nuclear Information System (INIS)

Fishman, R.S.

1989-01-01

The force-balance method is used to calculate the isothermal resistivity to first order in the electric field. To lowest order in the impurity potential, the isothermal resistivity disagrees with the adiabatic results of the Kubo formula and the Boltzmann equation. However, an expansion of the isothermal resistivity in powers of the impurity potential is divergent, with two sets of divergent terms. The first set arises from the density matrix of the relative electron-phonon system. The second set arises from the explicit dependence of the density matrix on the electric field, which was ignored by force-balance calculations. These divergent contributions are calculated inductively, by applying a recursion relation for the Green's functions. Using the λ 2 t→∞ limit of van Hove, I show that the resummation of these divergent terms yields the same result for the resistivity as the adiabatic calculations, in direct analogy with the work of Argyres and Sigel, and Huberman and Chester

Self-consistent nonlinearly polarizable shell-model dynamics for ferroelectric materials

International Nuclear Information System (INIS)

Mkam Tchouobiap, S.E.; Kofane, T.C.; Ngabireng, C.M.

2002-11-01

We investigate the dynamical properties of the polarizable shellmodel with a symmetric double Morse-type electron-ion interaction in one ionic species. A variational calculation based on the Self-Consistent Einstein Model (SCEM) shows that a theoretical ferroelectric (FE) transition temperature can be derive which demonstrates the presence of a first-order phase transition for the potassium selenate (K 2 SeO 4 ) crystal around Tc 91.5 K. Comparison of the model calculation with the experimental critical temperature yields satisfactory agreement. (author)

Self-assessment: Strategy for higher standards, consistency, and performance

International Nuclear Information System (INIS)

Ide, W.E.

1996-01-01

In late 1994, Palo Verde operations underwent a transformation from a unitized structure to a single functional unit. It was necessary to build consistency in watchstanding practices and create a shared mission. Because there was a lack of focus on actual plant operations and because personnel were deeply involved with administrative tasks, command and control of evolutions were weak. Improvement was needed. Consistent performance standards have been set for all three operating units. These expectation focus on nuclear, radiological, and industrial safety. Straightforward descriptions of watchstanding and monitoring practices have been provided to all department personnel. The desired professional and leadership qualities for employee conduct have been defined and communicated thoroughly. A healthy and competitive atmosphere developed with the successful implementation of these standards. Overall performance improved. The auxiliary operators demonstrated increased pride and ownership in the performance of their work activities. In addition, their morale improved. Crew teamwork improved as well as the quality of shift briefs. There was a decrease in the noise level and the administrative functions in the control room. The use of self-assessment helped to anchor and define higher and more consistent standards. The proof of Palo Verde's success was evident when an Institute of Nuclear Power Operations finding was turned into a strength within 1 yr

A self-consistent spin-diffusion model for micromagnetics

KAUST Repository

Abert, Claas; Ruggeri, Michele; Bruckner, Florian; Vogler, Christoph; Manchon, Aurelien; Praetorius, Dirk; Suess, Dieter

2016-01-01

We propose a three-dimensional micromagnetic model that dynamically solves the Landau-Lifshitz-Gilbert equation coupled to the full spin-diffusion equation. In contrast to previous methods, we solve for the magnetization dynamics and the electric potential in a self-consistent fashion. This treatment allows for an accurate description of magnetization dependent resistance changes. Moreover, the presented algorithm describes both spin accumulation due to smooth magnetization transitions and due to material interfaces as in multilayer structures. The model and its finite-element implementation are validated by current driven motion of a magnetic vortex structure. In a second experiment, the resistivity of a magnetic multilayer structure in dependence of the tilting angle of the magnetization in the different layers is investigated. Both examples show good agreement with reference simulations and experiments respectively.

A self-consistent spin-diffusion model for micromagnetics

KAUST Repository

Abert, Claas

2016-12-17

We propose a three-dimensional micromagnetic model that dynamically solves the Landau-Lifshitz-Gilbert equation coupled to the full spin-diffusion equation. In contrast to previous methods, we solve for the magnetization dynamics and the electric potential in a self-consistent fashion. This treatment allows for an accurate description of magnetization dependent resistance changes. Moreover, the presented algorithm describes both spin accumulation due to smooth magnetization transitions and due to material interfaces as in multilayer structures. The model and its finite-element implementation are validated by current driven motion of a magnetic vortex structure. In a second experiment, the resistivity of a magnetic multilayer structure in dependence of the tilting angle of the magnetization in the different layers is investigated. Both examples show good agreement with reference simulations and experiments respectively.

Time-dependent restricted-active-space self-consistent-field theory for bosonic many-body systems

International Nuclear Information System (INIS)

Lévêque, Camille; Madsen, Lars Bojer

2017-01-01

We develop an ab initio time-dependent wavefunction based theory for the description of a many-body system of cold interacting bosons. Like the multi-configurational time-dependent Hartree method for bosons (MCTDHB), the theory is based on a configurational interaction Ansatz for the many-body wavefunction with time-dependent self-consistent-field orbitals. The theory generalizes the MCTDHB method by incorporating restrictions on the active space of the orbital excitations. The restrictions are specified based on the physical situation at hand. The equations of motion of this time-dependent restricted-active-space self-consistent-field (TD-RASSCF) theory are derived. The similarity between the formal development of the theory for bosons and fermions is discussed. The restrictions on the active space allow the theory to be evaluated under conditions where other wavefunction based methods due to exponential scaling in the numerical effort cannot, and to clearly identify the excitations that are important for an accurate description, significantly beyond the mean-field approach. For ground state calculations we find it to be important to allow a few particles to have the freedom to move in many orbitals, an insight facilitated by the flexibility of the restricted-active-space Ansatz . Moreover, we find that a high accuracy can be obtained by including only even excitations in the many-body self-consistent-field wavefunction. Time-dependent simulations of harmonically trapped bosons subject to a quenching of their noncontact interaction, show failure of the mean-field Gross-Pitaevskii approach within a fraction of a harmonic oscillation period. The TD-RASSCF theory remains accurate at much reduced computational cost compared to the MCTDHB method. Exploring the effect of changes of the restricted-active-space allows us to identify that even self-consistent-field excitations are mainly responsible for the accuracy of the method. (paper)

Truncated Wigner dynamics and conservation laws

Science.gov (United States)

Drummond, Peter D.; Opanchuk, Bogdan

2017-10-01

Ultracold Bose gases can be used to experimentally test many-body theory predictions. Here we point out that both exact conservation laws and dynamical invariants exist in the topical case of the one-dimensional Bose gas, and these provide an important validation of methods. We show that the first four quantum conservation laws are exactly conserved in the approximate truncated Wigner approach to many-body quantum dynamics. Center-of-mass position variance is also exactly calculable. This is nearly exact in the truncated Wigner approximation, apart from small terms that vanish as N-3 /2 as N →∞ with fixed momentum cutoff. Examples of this are calculated in experimentally relevant, mesoscopic cases.

Total energy calculation of perovskite, BaTiO3, by self-consistent

Indian Academy of Sciences (India)

Unknown

rgy, lattice constant, density of states, band structure etc using self-consistent tight binding method. ... share the paraelectric simple-cubic perovskite structure .... of neighbouring ions. In order to find the ground state, we solve the variation problem, minimizing Etot with respect to the coefficients, .*,λµ ic. The final equation is.

Self-consistent modelling of X-ray photoelectron spectra from air-exposed polycrystalline TiN thin films

Energy Technology Data Exchange (ETDEWEB)

Greczynski, G., E-mail: grzgr@ifm.liu.se; Hultman, L.

2016-11-30

Highlights: • We present first self-consistent model of TiN core level spectra with a cross-peak qualitative and quantitative agreement. • Model is tested for a series of TiN thin films oxidized to different extent by varying the venting temperature. • Conventional deconvolution process relies on reference binding energies that typically show large spread introducing ambiguity. • By imposing requirement of quantitative cross-peak self-consistency reliability of extracted chemical information is enhanced. • We propose that the cross-peak self-consistency should be a prerequisite for reliable XPS peak modelling. - Abstract: We present first self-consistent modelling of x-ray photoelectron spectroscopy (XPS) Ti 2p, N 1s, O 1s, and C 1s core level spectra with a cross-peak quantitative agreement for a series of TiN thin films grown by dc magnetron sputtering and oxidized to different extent by varying the venting temperature T{sub v} of the vacuum chamber before removing the deposited samples. So-obtained film series constitute a model case for XPS application studies, where certain degree of atmosphere exposure during sample transfer to the XPS instrument is unavoidable. The challenge is to extract information about surface chemistry without invoking destructive pre-cleaning with noble gas ions. All TiN surfaces are thus analyzed in the as-received state by XPS using monochromatic Al Kα radiation (hν = 1486.6 eV). Details of line shapes and relative peak areas obtained from deconvolution of the reference Ti 2p and N 1 s spectra representative of a native TiN surface serve as an input to model complex core level signals from air-exposed surfaces, where contributions from oxides and oxynitrides make the task very challenging considering the influence of the whole deposition process at hand. The essential part of the presented approach is that the deconvolution process is not only guided by the comparison to the reference binding energy values that often show

The numerical multiconfiguration self-consistent field approach for atoms

International Nuclear Information System (INIS)

Stiehler, Johannes

1995-12-01

The dissertation uses the Multiconfiguration Self-Consistent Field Approach to specify the electronic wave function of N electron atoms in a static electrical field. It presents numerical approaches to describe the wave functions and introduces new methods to compute the numerical Fock equations. Based on results computed with an implemented computer program the universal application, flexibility and high numerical precision of the presented approach is shown. RHF results and for the first time MCSCF results for polarizabilities and hyperpolarizabilities of various states of the atoms He to Kr are discussed. In addition, an application to interpret a plasma spectrum of gallium is presented. (orig.)

Self-consistent treatment of nuclear collective motion with an application to the giant-dipole resonance

International Nuclear Information System (INIS)

Liran, S.; Technion-Israel Inst. of Tech., Haifa. Dept. of Physics)

1977-01-01

This paper extends the recent theory of Liran, Scheefer, Scheid and Greiner on non-adiabatic cranking and nuclear collective motion. In the present work we show the self-consistency conditions for the collective motion, which are indicated by appropriate time-dependent Lagrange multipliers, can be treated explicitly. The energy conservation and the self-consistency condition in the case of one collective degree of freedom are expressed in differential form. This leads to a set of coupled differential equations in time for the many-body wave function, for the collective variable and for the Lagrange multiplier. An iteration procedure similar to that of the previous work is also presented. As an illustrative example, we investigate Brink's single-particle description of the giant-dipole resonance. In this case, the important role played by non-adiabaticity and self-consistency in determining the collective motion is demonstrated and discussed. We also consider the fact that in this example of a fast collective motion, the adiabatic cranking model of Inglis gives the correct mass parameter. (orig.) [de

Gate-controlled current and inelastic electron tunneling spectrum of benzene: a self-consistent study.

Science.gov (United States)

Liang, Y Y; Chen, H; Mizuseki, H; Kawazoe, Y

2011-04-14

We use density functional theory based nonequilibrium Green's function to self-consistently study the current through the 1,4-benzenedithiol (BDT). The elastic and inelastic tunneling properties through this Au-BDT-Au molecular junction are simulated, respectively. For the elastic tunneling case, it is found that the current through the tilted molecule can be modulated effectively by the external gate field, which is perpendicular to the phenyl ring. The gate voltage amplification comes from the modulation of the interaction between the electrodes and the molecules in the junctions. For the inelastic case, the electron tunneling scattered by the molecular vibrational modes is considered within the self-consistent Born approximation scheme, and the inelastic electron tunneling spectrum is calculated.

Bicontinuous Phases in Diblock Copolymer/Homopolymer Blends: Simulation and Self-Consistent Field Theory

KAUST Repository

Martínez-Veracoechea, Francisco J.; Escobedo, Fernando A.

2009-01-01

A combination of particle-based simulations and self-consistent field theory (SCFT) is used to study the stabilization of multiple ordered bicontinuous phases in blends of a diblock copolymer (DBC) and a homopolymer. The double-diamond phase (DD

Self-consistent spectral function for non-degenerate Coulomb systems and analytic scaling behaviour

International Nuclear Information System (INIS)

Fortmann, Carsten

2008-01-01

Novel results for the self-consistent single-particle spectral function and self-energy are presented for non-degenerate one-component Coulomb systems at various densities and temperatures. The GW (0) -method for the dynamical self-energy is used to include many-particle correlations beyond the quasi-particle approximation. The self-energy is analysed over a broad range of densities and temperatures (n = 10 17 cm -3 -10 27 cm -3 , T = 10 2 eV/k B -10 4 eV/k B ). The spectral function shows a systematic behaviour, which is determined by collective plasma modes at small wavenumbers and converges towards a quasi-particle resonance at higher wavenumbers. In the low density limit, the numerical results comply with an analytic scaling law that is presented for the first time. It predicts a power-law behaviour of the imaginary part of the self-energy, ImΣ ∼ -n 1/4 . This resolves a long time problem of the quasi-particle approximation which yields a finite self-energy at vanishing density

Calculation of the self-consistent current distribution and coupling of an RF antenna array

International Nuclear Information System (INIS)

Ballico, M.; Puri, S.

1993-10-01

A self-consistent calculation of the antenna current distribution and fields in an axisymmetric cylindrical geometry for the ICRH antenna-plasma coupling problem is presented. Several features distinguish this calculation from other codes presently available. 1. Variational form: The formulation of the self consistent antenna current problem in a variational form allows good convergence and stability of the algorithm. 2. Multiple straps: Allows modelling of (a) the current distribution across the width of the strap (by dividing it up into sub straps) (b) side limiters and septum (c) antenna cross-coupling. 3. Analytic calculation of the antenna field and calculation of the antenna self-consistent current distribution, (given the surface impedance matrix) gives rapid calculation. 4. Framed for parallel computation on several different parallel architectures (as well as serial) gives a large speed improvement to the user. Results are presented for both Alfven wave heating and current drive antenna arrays, showing the optimal coupling to be achieved for toroidal mode numbers 8< n<10 for typical ASDEX upgrade plasmas. Simulations of the ASDEX upgrade antenna show the importance of the current distribution across the antenna and of image currents flowing in the side limiters, and an analysis of a proposed asymmetric ITER antenna is presented. (orig.)

Solution of the Stieltjes truncated matrix moment problem

Directory of Open Access Journals (Sweden)

Vadim M. Adamyan

2005-01-01

Full Text Available The truncated Stieltjes matrix moment problem consisting in the description of all matrix distributions \\(\\boldsymbol{\\sigma}(t\\ on \\([0,\\infty\\ with given first \\(2n+1\\ power moments \\((\\mathbf{C}_j_{n=0}^j\\ is solved using known results on the corresponding Hamburger problem for which \\(\\boldsymbol{\\sigma}(t\\ are defined on \\((-\\infty,\\infty\\. The criterion of solvability of the Stieltjes problem is given and all its solutions in the non-degenerate case are described by selection of the appropriate solutions among those of the Hamburger problem for the same set of moments. The results on extensions of non-negative operators are used and a purely algebraic algorithm for the solution of both Hamburger and Stieltjes problems is proposed.

Relation between Tolman length and isothermal compressibility for simple liquids

International Nuclear Information System (INIS)

Wang Xiao-Song; Zhu Ru-Zeng

2013-01-01

The Tolman length δ 0 of a liquid with a plane surface has attracted increasing theoretical attention in recent years, but the expression of Tolman length in terms of observable quantities is still not very clear. In 2001, Bartell gave a simple expression of Tolman length δ 0 in terms of isothermal compressibility. However, this expression predicts that Tolman length is always negative, which is contrary to the results of molecular dynamics simulations (MDS) for simple liquids. In this paper, this contradiction is analyzed and the reason for the discrepancy in the sign is found. In addition, we introduce a new expression of Tolman length in terms of isothermal compressibility for simple fluids not near the critical points under some weak restrictions. The Tolman length of simple liquids calculated by using this formula is consistent with that obtained using MDS regarding the sign

Fast, kinetically self-consistent simulation of RF modulated plasma boundary sheaths

International Nuclear Information System (INIS)

Shihab, Mohammed; Ziegler, Dennis; Brinkmann, Ralf Peter

2012-01-01

A mathematical model is presented which enables the efficient, kinetically self-consistent simulation of RF modulated plasma boundary sheaths in all technically relevant discharge regimes. It is defined on a one-dimensional geometry where a Cartesian x-axis points from the electrode or wall at x E ≡ 0 towards the plasma bulk. An arbitrary endpoint x B is chosen ‘deep in the bulk’. The model consists of a set of kinetic equations for the ions, Boltzmann's relation for the electrons and Poisson's equation for the electrical field. Boundary conditions specify the ion flux at x B and a periodically—not necessarily harmonically—modulated sheath voltage V(t) or sheath charge Q(t). The equations are solved in a statistical sense. However, it is not the well-known particle-in-cell (PIC) scheme that is employed, but an alternative iterative algorithm termed ensemble-in-spacetime (EST). The basis of the scheme is a discretization of the spacetime, the product of the domain [x E , x B ] and the RF period [0, T]. Three modules are called in a sequence. A Monte Carlo module calculates the trajectories of a large set of ions from their start at x B until they reach the electrode at x E , utilizing the potential values on the nodes of the spatio-temporal grid. A harmonic analysis module reconstructs the Fourier modes n im (x) of the ion density n i (x, t) from the calculated trajectories. A field module finally solves the Boltzmann-Poisson equation with the calculated ion densities to generate an updated set of potential values for the spatio-temporal grid. The iteration is started with the potential values of a self-consistent fluid model and terminates when the updates become sufficiently small, i.e. when self-consistency is achieved. A subsequent post-processing determines important quantities, in particular the phase-resolved and phase-averaged values of the ion energy and angular distributions and the total energy flux at the electrode. A drastic reduction of the

IMPETUS: Consistent SPH calculations of 3D spherical Bondi accretion onto a black hole

Science.gov (United States)

Ramírez-Velasquez, J. M.; Sigalotti, L. Di G.; Gabbasov, R.; Cruz, F.; Klapp, J.

2018-04-01

We present three-dimensional calculations of spherically symmetric Bondi accretion onto a stationary supermassive black hole (SMBH) of mass 108M⊙ within a radial range of 0.02 - 10 pc, using a modified version of the smoothed particle hydrodynamics (SPH) GADGET-2 code, which ensures approximate first-order consistency (i.e., second-order accuracy) for the particle approximation. First-order consistency is restored by allowing the number of neighbours, nneigh, and the smoothing length, h, to vary with the total number of particles, N, such that the asymptotic limits nneigh → ∞ and h → 0 hold as N → ∞. The ability of the method to reproduce the isothermal (γ = 1) and adiabatic (γ = 5/3) Bondi accretion is investigated with increased spatial resolution. In particular, for the isothermal models the numerical radial profiles closely match the Bondi solution, except near the accretor, where the density and radial velocity are slightly underestimated. However, as nneigh is increased and h is decreased, the calculations approach first-order consistency and the deviations from the Bondi solution decrease. The density and radial velocity profiles for the adiabatic models are qualitatively similar to those for the isothermal Bondi accretion. Steady-state Bondi accretion is reproduced by the highly resolved consistent models with a percent relative error of ≲ 1% for γ = 1 and ˜9% for γ = 5/3, with the adiabatic accretion taking longer than the isothermal case to reach steady flow. The performance of the method is assessed by comparing the results with those obtained using the standard GADGET-2 and the GIZMO codes.

The accuracy of the time-dependent self-consistent-field approximation for inelastic collisions

DEFF Research Database (Denmark)

Henriksen, Niels Engholm; Billing, Gert D.; Hansen, Flemming Yssing

1992-01-01

We study the accuracy of the time-dependent self-consistent-field approximation for collinear inelastic collisions between an atom and a diatomic molecule. Individual state-to-state transition probabilities, total energy transfer. and the global description of the wavefunction is considered...

Self-consistent simulation of the CSR effect on beam emittance

CERN Document Server

Li, R

1999-01-01

When a microbunch with high charge traverses a curved trajectory, the curvature-induced Coherent Synchrotron Radiation (CSR) and space-charge forces may cause serious emittance degradation. Earlier analyses based on rigid-line charge model are helpful in understanding the mechanism of this curvature-induced bunch self-interaction. In reality, however, the bunch has finite transverse size and its dynamics respond to the CSR force. In this paper, we present the first self-consistent simulation for the study of the impact of CSR on beam optics. With the bunch represented by a set of macroparticles, the dynamics of the bunch under the influence of the CSR force are simulated, where the CSR force in turn depends on the history of bunch charge distribution and current density in accordance to causality. This simulation is bench-marked with previous analytical results for a rigid-line bunch. The algorithm applied in the simulation will be presented, along with the simulation results obtained for bending systems in t...

Self-consistent simulation of the CSR effect on beam emittance

International Nuclear Information System (INIS)

Li, R.

1999-01-01

When a microbunch with high charge traverses a curved trajectory, the curvature-induced Coherent Synchrotron Radiation (CSR) and space-charge forces may cause serious emittance degradation. Earlier analyses based on rigid-line charge model are helpful in understanding the mechanism of this curvature-induced bunch self-interaction. In reality, however, the bunch has finite transverse size and its dynamics respond to the CSR force. In this paper, we present the first self-consistent simulation for the study of the impact of CSR on beam optics. With the bunch represented by a set of macroparticles, the dynamics of the bunch under the influence of the CSR force are simulated, where the CSR force in turn depends on the history of bunch charge distribution and current density in accordance to causality. This simulation is bench-marked with previous analytical results for a rigid-line bunch. The algorithm applied in the simulation will be presented, along with the simulation results obtained for bending systems in the Jefferson Lab FEL lattice

Inference for shared-frailty survival models with left-truncated data

NARCIS (Netherlands)

van den Berg, G.J.; Drepper, B.

2016-01-01

Shared-frailty survival models specify that systematic unobserved determinants of duration outcomes are identical within groups of individuals. We consider random-effects likelihood-based statistical inference if the duration data are subject to left-truncation. Such inference with left-truncated

THERMODYNAMICS AND ADSORPTION ISOTHERMS FOR THE ...

African Journals Online (AJOL)

BAFFA

data were tested using Freundlich and Langmuir adsorption isotherms. The values of the numeric constants ... Keywords: Adsorbate, Adsorbent, Adsorption isotherms, Maize cob, Thermodynamics. INTRODUCTION. Maize (Zea mays) ... several times with water, air – dried and ground to. 850μm particle size and finally kept ...

A Self Consistent Multiprocessor Space Charge Algorithm that is Almost Embarrassingly Parallel

International Nuclear Information System (INIS)

Nissen, Edward; Erdelyi, B.; Manikonda, S.L.

2012-01-01

We present a space charge code that is self consistent, massively parallelizeable, and requires very little communication between computer nodes; making the calculation almost embarrassingly parallel. This method is implemented in the code COSY Infinity where the differential algebras used in this code are important to the algorithm's proper functioning. The method works by calculating the self consistent space charge distribution using the statistical moments of the test particles, and converting them into polynomial series coefficients. These coefficients are combined with differential algebraic integrals to form the potential, and electric fields. The result is a map which contains the effects of space charge. This method allows for massive parallelization since its statistics based solver doesn't require any binning of particles, and only requires a vector containing the partial sums of the statistical moments for the different nodes to be passed. All other calculations are done independently. The resulting maps can be used to analyze the system using normal form analysis, as well as advance particles in numbers and at speeds that were previously impossible.

General variational many-body theory with complete self-consistency for trapped bosonic systems

International Nuclear Information System (INIS)

Streltsov, Alexej I.; Alon, Ofir E.; Cederbaum, Lorenz S.

2006-01-01

In this work we develop a complete variational many-body theory for a system of N trapped bosons interacting via a general two-body potential. The many-body solution of this system is expanded over orthogonal many-body basis functions (configurations). In this theory both the many-body basis functions and the respective expansion coefficients are treated as variational parameters. The optimal variational parameters are obtained self-consistently by solving a coupled system of noneigenvalue--generally integro-differential--equations to get the one-particle functions and by diagonalizing the secular matrix problem to find the expansion coefficients. We call this theory multiconfigurational Hartree theory for bosons or MCHB(M), where M specifies explicitly the number of one-particle functions used to construct the configurations. General rules for evaluating the matrix elements of one- and two-particle operators are derived and applied to construct the secular Hamiltonian matrix. We discuss properties of the derived equations. We show that in the limiting cases of one configuration the theory boils down to the well-known Gross-Pitaevskii and the recently developed multi-orbital mean fields. The invariance of the complete solution with respect to unitary transformations of the one-particle functions is utilized to find the solution with the minimal number of contributing configurations. In the second part of our work we implement and apply the developed theory. It is demonstrated that for any practical computation where the configurational space is restricted, the description of trapped bosonic systems strongly depends on the choice of the many-body basis set used, i.e., self-consistency is of great relevance. As illustrative examples we consider bosonic systems trapped in one- and two-dimensional symmetric and asymmetric double well potentials. We demonstrate that self-consistency has great impact on the predicted physical properties of the ground and excited states

Immature truncated O-glycophenotype of cancer directly induces oncogenic features

DEFF Research Database (Denmark)

Radhakrishnan, Prakash; Dabelsteen, Sally; Madsen, Frey Brus

2014-01-01

Aberrant expression of immature truncated O-glycans is a characteristic feature observed on virtually all epithelial cancer cells, and a very high frequency is observed in early epithelial premalignant lesions that precede the development of adenocarcinomas. Expression of the truncated O-glycan s...

Social supports and mental health: a cross-sectional study on the correlation of self-consistency and congruence in China.

Science.gov (United States)

Gu, YanMei; Hu, Jie; Hu, YaPing; Wang, JianRong

2016-06-28

Psychosocial job characteristics require nursing staff with high self-consistency and good mental health. However, the attention and effort of such study remained very limited in China. A self-administered questionnaire was distributed to the bedside nurses in an affiliated hospital of Hebei Medical University, China. Of 218 registered bedside nurses eligible to participate in the survey anonymously, the data producing sample of 172 subjects resulted in a 79 % of effective response rate.. The Social Support Rating Scale was used to measure social support, and the Self-Consistency and Congruence Scale were used to measure mental health. Compared with the normal referenced group of college students, higher self-flexibility scores, lower self-conflict and self-stethoscope scores from the sample group were obtained with statistical significance in self-conflict scores. The close correlations were observed between participants' social support and Self-Consistency and Congruence Scale score. The difference of Social Support Rating Scale score was significant in demographic features including years of work, marital status, only child family, and levels of cooperation with other health worker. Bedside nurses in this study show a better inner harmony, and their Self-Consistency and Congruence closely correlates with the levels of social support. Thus, it is substantial to improve inner perception of support and external factors, such as the workplace support, and offer beneficial social environment to improve the bedside nurse's sub-health symptoms and decrease the high turnover rate.

The effects of feedback self-consistency, therapist status, and attitude toward therapy on reaction to personality feedback.

Science.gov (United States)

Collins, David R; Stukas, Arthur A

2006-08-01

Individuals' reactions to interpersonal feedback may depend on characteristics of the feedback and the feedback source. The present authors examined the effects of experimentally manipulated personality feedback that they--in the guise of therapists--e-mailed to participants on the degree of their acceptance of the feedback. Consistent with Self-Verification Theory (W. B. Swann Jr., 1987), participants accepted feedback that was consistent with their self-views more readily than they did feedback that was inconsistent with their self-views. Furthermore, the authors found main effects for therapist's status and participant's attitude toward therapy. Significant interactions showed effects in which high-status therapists and positive client attitudes increased acceptance of self-inconsistent feedback, effects that were only partially mediated by clients' perceptions of therapist competence. The present results indicate the possibility that participants may be susceptible to self-concept change or to self-fulfilling prophecy effects in therapy when they have a positive attitude toward therapy or are working with a high-status therapist.

1ST-ORDER NONADIABATIC COUPLING MATRIX-ELEMENTS FROM MULTICONFIGURATIONAL SELF-CONSISTENT-FIELD RESPONSE THEORY

DEFF Research Database (Denmark)

Bak, Keld L.; Jørgensen, Poul; Jensen, H.J.A.

1992-01-01

A new scheme for obtaining first-order nonadiabatic coupling matrix elements (FO-NACME) for multiconfigurational self-consistent-field (MCSCF) wave functions is presented. The FO-NACME are evaluated from residues of linear response functions. The residues involve the geometrical response of a ref......A new scheme for obtaining first-order nonadiabatic coupling matrix elements (FO-NACME) for multiconfigurational self-consistent-field (MCSCF) wave functions is presented. The FO-NACME are evaluated from residues of linear response functions. The residues involve the geometrical response...... to the full configuration interaction limit. Comparisons are made with state-averaged MCSCF results for MgH2 and finite-difference configuration interaction by perturbation with multiconfigurational zeroth-order wave function reflected by interactive process (CIPSI) results for BH....

Self-consistent field theory of protein adsorption in a non-Gaussian polyelectrolyte brush

NARCIS (Netherlands)

Biesheuvel, P.M.; Leermakers, F.A.M.; Stuart, M.A.C.

2006-01-01

To describe adsorption of globular protein molecules in a polyelectrolyte brush we use the strong-stretching approximation of the Edwards self-consistent field equation, combined with corrections for a non-Gaussian brush. To describe chemical potentials in this mixture of (globular) species of

Self-consistency condition and high-density virial theorem in relativistic many-particle systems

International Nuclear Information System (INIS)

Kalman, G.; Canuto, V.; Datta, B.

1976-01-01

In order for the thermodynamic and kinetic definitions of the chemical potential and the pressure to lead to identical results a nontrivial self-consistency criterion has to be satisfied. This, in turn, leads to a virial-like theorem in the high-density limit

The internal consistency and validity of the Self-assessment Parkinson's Disease Disability Scale.

NARCIS (Netherlands)

Biemans, M.A.J.E.; Dekker, J.; Woude, L.H.V. van der

2001-01-01

OBJECTIVE: To test the consistency and validity of the Self-assessment Parkinson's Disease Disability Scale in patients with Parkinson's disease living at home. DESIGN: Patients with Parkinson's disease responded to a set of questionnaires. In addition, an observation of the performance of daily

Internal consistency and validity of the self-assessment Parkinson's Disease disability scale. Abstract.

NARCIS (Netherlands)

Dekker, J.; Biemans, M.A.J.E.; Woude, L.H.V. van der

2000-01-01

OBJECTIVE: To test the consistency and validity of the Self-assessment Parkinson's Disease Disability Scale in patients with Parkinson's disease living at home. DESIGN: Patients with Parkinson's disease responded to a set of questionnaires. In addition, an observation of the performance of daily

Density distribution function of a self-gravitating isothermal compressible turbulent fluid in the context of molecular clouds ensembles

Science.gov (United States)

Donkov, Sava; Stefanov, Ivan Z.

2018-03-01

We have set ourselves the task of obtaining the probability distribution function of the mass density of a self-gravitating isothermal compressible turbulent fluid from its physics. We have done this in the context of a new notion: the molecular clouds ensemble. We have applied a new approach that takes into account the fractal nature of the fluid. Using the medium equations, under the assumption of steady state, we show that the total energy per unit mass is an invariant with respect to the fractal scales. As a next step we obtain a non-linear integral equation for the dimensionless scale Q which is the third root of the integral of the probability distribution function. It is solved approximately up to the leading-order term in the series expansion. We obtain two solutions. They are power-law distributions with different slopes: the first one is -1.5 at low densities, corresponding to an equilibrium between all energies at a given scale, and the second one is -2 at high densities, corresponding to a free fall at small scales.

Probability distributions with truncated, log and bivariate extensions

CERN Document Server

Thomopoulos, Nick T

2018-01-01

This volume presents a concise and practical overview of statistical methods and tables not readily available in other publications. It begins with a review of the commonly used continuous and discrete probability distributions. Several useful distributions that are not so common and less understood are described with examples and applications in full detail: discrete normal, left-partial, right-partial, left-truncated normal, right-truncated normal, lognormal, bivariate normal, and bivariate lognormal. Table values are provided with examples that enable researchers to easily apply the distributions to real applications and sample data. The left- and right-truncated normal distributions offer a wide variety of shapes in contrast to the symmetrically shaped normal distribution, and a newly developed spread ratio enables analysts to determine which of the three distributions best fits a particular set of sample data. The book will be highly useful to anyone who does statistical and probability analysis. This in...

Surface self-diffusion of adatom on Pt cluster with truncated octahedron structure

International Nuclear Information System (INIS)

Yang Jianyu; Hu Wangyu; Chen Shuguang

2010-01-01

Surface diffusion of single Pt adatom on Pt cluster with truncated octahedron structure is investigated through a combination of molecular dynamics and nudged elastic band method. Using an embedded atom method to describe the atomic interactions, the minimum energy paths are determined and the energy barriers for adatom diffusion across and along step are evaluated. The diffusion of adatom crossing step edge between {111} and {100} facets has a surprisingly low barrier of 0.03 eV, which is 0.12 eV lower than the barrier for adatom diffusion from {111} to neighboring {111} facet. Owing to the small barrier of adatom diffusion across the step edge between {111} and {100} facets, the diffusion of adatom along the step edge cannot occur. The molecular dynamics simulations at low temperatures also support these results. Our results show that mass transport will prefer step with {100} microfacet and the Pt clusters can have only {111} facets in epitaxial growth.

Isothermal martensite formation at sub-zero temperatures

DEFF Research Database (Denmark)

Stojko, Allan; Hansen, Mikkel Fougt; Slycke, Jan

2010-01-01

austenitized and quenched in oil and thereafter investigated with vibrating sample agnetometry, which allows a quantitative assessment of the fraction of retained austenite as a function of the subzero temperature and time. Isothermal martensite formation was observed on interrupting the continuous cooling (5...... with a continuation of the martensitic transformation. On prolonged isothermal holding a volume reduction was observed for AISI 52100, but not for AISI 1070. A mechanism is proposed that explains the occurrence of isothermal martensite formation....

Impact of degree truncation on the spread of a contagious process on networks.

Science.gov (United States)

Harling, Guy; Onnela, Jukka-Pekka

2018-03-01

Understanding how person-to-person contagious processes spread through a population requires accurate information on connections between population members. However, such connectivity data, when collected via interview, is often incomplete due to partial recall, respondent fatigue or study design, e.g., fixed choice designs (FCD) truncate out-degree by limiting the number of contacts each respondent can report. Past research has shown how FCD truncation affects network properties, but its implications for predicted speed and size of spreading processes remain largely unexplored. To study the impact of degree truncation on predictions of spreading process outcomes, we generated collections of synthetic networks containing specific properties (degree distribution, degree-assortativity, clustering), and also used empirical social network data from 75 villages in Karnataka, India. We simulated FCD using various truncation thresholds and ran a susceptible-infectious-recovered (SIR) process on each network. We found that spreading processes propagated on truncated networks resulted in slower and smaller epidemics, with a sudden decrease in prediction accuracy at a level of truncation that varied by network type. Our results have implications beyond FCD to truncation due to any limited sampling from a larger network. We conclude that knowledge of network structure is important for understanding the accuracy of predictions of process spread on degree truncated networks.

Thermodynamically self-consistent theory for the Blume-Capel model.

Science.gov (United States)

Grollau, S; Kierlik, E; Rosinberg, M L; Tarjus, G

2001-04-01

We use a self-consistent Ornstein-Zernike approximation to study the Blume-Capel ferromagnet on three-dimensional lattices. The correlation functions and the thermodynamics are obtained from the solution of two coupled partial differential equations. The theory provides a comprehensive and accurate description of the phase diagram in all regions, including the wing boundaries in a nonzero magnetic field. In particular, the coordinates of the tricritical point are in very good agreement with the best estimates from simulation or series expansion. Numerical and analytical analysis strongly suggest that the theory predicts a universal Ising-like critical behavior along the lambda line and the wing critical lines, and a tricritical behavior governed by mean-field exponents.

Self-consistency constraints on turbulent magnetic transport and relaxation in collisionless plasma

International Nuclear Information System (INIS)

Terry, P.W.; Diamond, P.H.; Hahm, T.S.

1985-10-01

Novel constraints on collisionless relaxation and transport in drift-Alfven turbulence are reported. These constraints arise due to the consideration of mode coupling and incoherent fluctuations and the proper application of self-consistency conditions. The result that electrostatic fluctuations alone regulate transport in drift-Alfven turbulence follows directly. Quasilinear transport predictions are discussed in light of these constraints

An eigenvalue approach to quantum plasmonics based on a self-consistent hydrodynamics method.

Science.gov (United States)

Ding, Kun; Chan, C T

2018-02-28

Plasmonics has attracted much attention not only because it has useful properties such as strong field enhancement, but also because it reveals the quantum nature of matter. To handle quantum plasmonics effects, ab initio packages or empirical Feibelman d-parameters have been used to explore the quantum correction of plasmonic resonances. However, most of these methods are formulated within the quasi-static framework. The self-consistent hydrodynamics model offers a reliable approach to study quantum plasmonics because it can incorporate the quantum effect of the electron gas into classical electrodynamics in a consistent manner. Instead of the standard scattering method, we formulate the self-consistent hydrodynamics method as an eigenvalue problem to study quantum plasmonics with electrons and photons treated on the same footing. We find that the eigenvalue approach must involve a global operator, which originates from the energy functional of the electron gas. This manifests the intrinsic nonlocality of the response of quantum plasmonic resonances. Our model gives the analytical forms of quantum corrections to plasmonic modes, incorporating quantum electron spill-out effects and electrodynamical retardation. We apply our method to study the quantum surface plasmon polariton for a single flat interface.

The robustness of truncated Airy beam in PT Gaussian potentials media

Science.gov (United States)

Wang, Xianni; Fu, Xiquan; Huang, Xianwei; Yang, Yijun; Bai, Yanfeng

2018-03-01

The robustness of truncated Airy beam in parity-time (PT) symmetric Gaussian potentials media is numerically investigated. A high-peak power beam sheds from the Airy beam due to the media modulation while the Airy wavefront still retain its self-bending and non-diffraction characteristics under the influence of modulation parameters. Increasing the modulation factor results in the smaller value of maximum power of the center beam, and the opposite trend occurs with the increment of the modulation depth. However, the parabolic trajectory of the Airy wavefront does not be influenced. By utilizing the unique features, the Airy beam can be used as a long distance transmission source under the PT symmetric Gaussian potentials medium.

The exact solution of self-consistent equations in the scanning near-field optic microscopy problem

DEFF Research Database (Denmark)

Lozovski, Valeri; Bozhevolnyi, Sergey I.

1999-01-01

The macroscopic approach that allows one to obtain an exact solution of the self-consistent equation of the Lippmann-Schwinger type is developed. The main idea of our method consist in usage of diagram technque for exact summation of the infinite series corresponding to the iteration procedure fo...

Self-consistent electric field effect on electron transport of ECH plasmas

International Nuclear Information System (INIS)

Chan, V.S.; Murakami, S.

1999-02-01

An algorithm is proposed which treats the ECH generated potential in a self-consistent way, by extending the Monte-Carlo Fokker-Planck method used by Murakami [S. Murakami et al., Proc. 17th IAEA Fusion Energy Conference, Yokohama, 1998 (International Atomic Energy Agency, Vienna, in press), paper CN-69/TH2/1]. The additional physics is expected to influence the transport of both thermal and suprathermal electrons in a helical toroidal system. (author)

Application of a truncated normal failure distribution in reliability testing

Science.gov (United States)

Groves, C., Jr.

1968-01-01

Statistical truncated normal distribution function is applied as a time-to-failure distribution function in equipment reliability estimations. Age-dependent characteristics of the truncated function provide a basis for formulating a system of high-reliability testing that effectively merges statistical, engineering, and cost considerations.

Truncation scheme of time-dependent density-matrix approach II

Energy Technology Data Exchange (ETDEWEB)

Tohyama, Mitsuru [Kyorin University School of Medicine, Mitaka, Tokyo (Japan); Schuck, Peter [Institut de Physique Nucleaire, IN2P3-CNRS, Universite Paris-Sud, Orsay (France); Laboratoire de Physique et de Modelisation des Milieux Condenses, CNRS et Universite Joseph Fourier, Grenoble (France)

2017-09-15

A truncation scheme of the Bogoliubov-Born-Green-Kirkwood-Yvon hierarchy for reduced density matrices, where a three-body density matrix is approximated by two-body density matrices, is improved to take into account a normalization effect. The truncation scheme is tested for the Lipkin model. It is shown that the obtained results are in good agreement with the exact solutions. (orig.)

A Combined Self-Consistent Method to Estimate the Effective Properties of Polypropylene/Calcium Carbonate Composites

Directory of Open Access Journals (Sweden)

Zhongqiang Xiong

2018-01-01

Full Text Available In this work, trying to avoid difficulty of application due to the irregular filler shapes in experiments, self-consistent and differential self-consistent methods were combined to obtain a decoupled equation. The combined method suggests a tenor γ independent of filler-contents being an important connection between high and low filler-contents. On one hand, the constant parameter can be calculated by Eshelby’s inclusion theory or the Mori–Tanaka method to predict effective properties of composites coinciding with its hypothesis. On the other hand, the parameter can be calculated with several experimental results to estimate the effective properties of prepared composites of other different contents. In addition, an evaluation index σ f ′ of the interactional strength between matrix and fillers is proposed based on experiments. In experiments, a hyper-dispersant was synthesized to prepare polypropylene/calcium carbonate (PP/CaCO3 composites up to 70 wt % of filler-content with dispersion, whose dosage was only 5 wt % of the CaCO3 contents. Based on several verifications, it is hoped that the combined self-consistent method is valid for other two-phase composites in experiments with the same application progress as in this work.

Identification and purification of truncated insulin-like growth factor I from porcine uterus. Evidence for high biological potency

International Nuclear Information System (INIS)

Ogasawara, M.; Karey, K.P.; Marquardt, H.; Sirbasku, D.A.

1989-01-01

The authors report the completion of the purification of uterine-derived growth factors (UDGF) described previously by this laboratory. During isolation, the mitogenic activity was monitored by using the human MCF-7 breast cancer cells in serum-free Ham's F12 and Dulbecco's modified Eagle's medium (1:1, v/v) containing 15 mM 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid, 200 μg/mL bovine serum albumin, and 10 μg/mL human transferrin. This medium sustained growth for several days in response to a single addition of growth factor. The mitogens were shown by protein microsequencing to be DES 1 → 3 to DES 1 → 6 forms of insulin-like growth factor I (truncated IGF-I). An M r estimated by 125 I labeling, urea-sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and autoradiography was consistent with a DES 1 → 3(4) N α truncation. Immunoadsorption and radioimmunoassay confirmed immunological properties equivalent to IGF-I. Radioreceptor assays showed truncated IGF-I was functionally equivalent to recombinant IGF-I. They conclude that the major acid-stable low-M r mitogenic activities isolated from uterus are very potent forms of truncated IGF-I capable of stimulating growth of epithelial and mesenchymal cells

Self-consistent electrostatic potential due to trapped plasma in the magnetosphere

International Nuclear Information System (INIS)

Miller, R.H.; Khazanov, G.V.

1993-01-01

The authors address the problem of the steady state confinement of plasma in a magnetic flux tube. They construct a steady state distribution function, under the assumption of no waves or collisions, using the kinematic constants of the motion, total energy and magnetic moment. The local particle densities are shown to be integrals over the equatorial distribution function for the particle of concern. The electric potential is determined by the imposition of quasineutrality. The authors show that their self consistent model produces potential drops which are consistent with the kinetic energy of the equatorially trapped particles. They comment on earlier work of Alfven and Faelthammar, and for a bi-Maxwellian distribution compare the results of the present model with the Alfven and Faelthammar model

Assembly of α-synuclein fibrils in nanoscale studied by peptide truncation and AFM

International Nuclear Information System (INIS)

Zhang Feng; Lin Xiaojing; Ji Lina; Du Haining; Tang Lin; He Jianhua; Hu Jun; Hu Hongyu

2008-01-01

α-Synuclein (α-Syn) fibrils are the major component of Lewy bodies that are closely associated with the pathogenesis of Parkinson's disease, but the mechanism for the fibril assembly remains poorly understood. Here we report using a combination of peptide truncation and atomic force microscopy (AFM) to elucidate the self-assembly and morphology of the α-Syn fibrils. The results show that protease K significantly slims the fibrils from the mean height of ∼6.6 to ∼4.7 nm, whereas chaotropic denaturant urea completely breaks down the fibrils into small particles. The in situ enzymatic digestion also results in thinning of the fibrils, giving rise to some nicks on the fibrils. Moreover, N- or C-terminally truncated α-Syn fragments assemble into thinner filaments with the heights depending on the peptide lengths. A nine-residue peptide corresponding to the homologous GAV-motif sequence can form very thin (∼2.2 nm) but long (>1 μm) filaments. Thus, the central sequence of α-Syn forms a fibrillar core by cross-β-structure that is flanked by two flexible termini, and the orientation of the fibril growth is perpendicular to the β-sheet structures

Importance-truncated shell model for multi-shell valence spaces

Energy Technology Data Exchange (ETDEWEB)

Stumpf, Christina; Vobig, Klaus; Roth, Robert [Institut fuer Kernphysik, TU Darmstadt (Germany)

2016-07-01

The valence-space shell model is one of the work horses in nuclear structure theory. In traditional applications, shell-model calculations are carried out using effective interactions constructed in a phenomenological framework for rather small valence spaces, typically spanned by one major shell. We improve on this traditional approach addressing two main aspects. First, we use new effective interactions derived in an ab initio approach and, thus, establish a connection to the underlying nuclear interaction providing access to single- and multi-shell valence spaces. Second, we extend the shell model to larger valence spaces by applying an importance-truncation scheme based on a perturbative importance measure. In this way, we reduce the model space to the relevant basis states for the description of a few target eigenstates and solve the eigenvalue problem in this physics-driven truncated model space. In particular multi-shell valence spaces are not tractable otherwise. We combine the importance-truncated shell model with refined extrapolation schemes to approximately recover the exact result. We present first results obtained in the importance-truncated shell model with the newly derived ab initio effective interactions for multi-shell valence spaces, e.g., the sdpf shell.

Analysis of self-consistency effects in range-separated density-functional theory with Møller-Plesset perturbation theory

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...

Maltose binding protein-fusion enhances the bioactivity of truncated forms of pig myostatin propeptide produced in E. coli.

Directory of Open Access Journals (Sweden)

Sang Beum Lee

Full Text Available Myostatin (MSTN is a potent negative regulator of skeletal muscle growth. MSTN propeptide (MSTNpro inhibits MSTN binding to its receptor through complex formation with MSTN, implying that MSTNpro can be a useful agent to improve skeletal muscle growth in meat-producing animals. Four different truncated forms of pig MSTNpro containing N-terminal maltose binding protein (MBP as a fusion partner were expressed in E. coli, and purified by the combination of affinity chromatography and gel filtration. The MSTN-inhibitory capacities of these proteins were examined in an in vitro gene reporter assay. A MBP-fused, truncated MSTNpro containing residues 42-175 (MBP-Pro42-175 exhibited the same MSTN-inhibitory potency as the full sequence MSTNpro. Truncated MSTNpro proteins containing either residues 42-115 (MBP-Pro42-115 or 42-98 (MBP-Pro42-98 also exhibited MSTN-inhibitory capacity even though the potencies were significantly lower than that of full sequence MSTNpro. In pull-down assays, MBP-Pro42-175, MBP-Pro42-115, and MBP-Pro42-98 demonstrated their binding to MSTN. MBP was removed from the truncated MSTNpro proteins by incubation with factor Xa to examine the potential role of MBP on MSTN-inhibitory capacity of those proteins. Removal of MBP from MBP-Pro42-175 and MBP-Pro42-98 resulted in 20-fold decrease in MSTN-inhibitory capacity of Pro42-175 and abolition of MSTN-inhibitory capacity of Pro42-98, indicating that MBP as fusion partner enhanced the MSTN-inhibitory capacity of those truncated MSTNpro proteins. In summary, this study shows that MBP is a very useful fusion partner in enhancing MSTN-inhibitory potency of truncated forms of MSTNpro proteins, and MBP-fused pig MSTNpro consisting of amino acid residues 42-175 is sufficient to maintain the full MSTN-inhibitory capacity.

Bounds and self-consistent estimates for elastic constants of polycrystals composed of orthorhombics or crystals with higher symmetries.

Science.gov (United States)

Berryman, James G

2011-04-01

Methods for computing Hashin-Shtrikman bounds and related self-consistent estimates of elastic constants for polycrystals composed of crystals having orthorhombic symmetry have been known for about three decades. However, these methods are underutilized, perhaps because of some perceived difficulties with implementing the necessary computational procedures. Several simplifications of these techniques are introduced, thereby reducing the overall computational burden, as well as the complications inherent in mapping out the Hashin-Shtrikman bounding curves. The self-consistent estimates of the effective elastic constants are very robust, involving a quickly converging iteration procedure. Once these self-consistent values are known, they may then be used to speed up the computations of the Hashin-Shtrikman bounds themselves. It is shown furthermore that the resulting orthorhombic polycrystal code can be used as well to compute both bounds and self-consistent estimates for polycrystals of higher-symmetry tetragonal, hexagonal, and cubic (but not trigonal) materials. The self-consistent results found this way are shown to be the same as those obtained using the earlier methods, specifically those methods designed specially for each individual symmetry type. But the Hashin-Shtrikman bounds found using the orthorhombic code are either the same or (more typically) tighter than those found previously for these special cases (i.e., tetragonal, hexagonal, and cubic). The improvement in the Hashin-Shtrikman bounds is presumably due to the additional degrees of freedom introduced into the available search space.

Approximate truncation robust computed tomography—ATRACT

International Nuclear Information System (INIS)

Dennerlein, Frank; Maier, Andreas

2013-01-01

We present an approximate truncation robust algorithm to compute tomographic images (ATRACT). This algorithm targets at reconstructing volumetric images from cone-beam projections in scenarios where these projections are highly truncated in each dimension. It thus facilitates reconstructions of small subvolumes of interest, without involving prior knowledge about the object. Our method is readily applicable to medical C-arm imaging, where it may contribute to new clinical workflows together with a considerable reduction of x-ray dose. We give a detailed derivation of ATRACT that starts from the conventional Feldkamp filtered-backprojection algorithm and that involves, as one component, a novel original formula for the inversion of the two-dimensional Radon transform. Discretization and numerical implementation are discussed and reconstruction results from both, simulated projections and first clinical data sets are presented. (paper)

Conservation laws and self-consistent sources for a super-CKdV equation hierarchy

International Nuclear Information System (INIS)

Li Li

2011-01-01

From the super-matrix Lie algebras, we consider a super-extension of the CKdV equation hierarchy in the present Letter, and propose the super-CKdV hierarchy with self-consistent sources. Furthermore, we establish the infinitely many conservation laws for the integrable super-CKdV hierarchy.

Conservation laws and self-consistent sources for a super-CKdV equation hierarchy

Energy Technology Data Exchange (ETDEWEB)

Li Li, E-mail: li07099@163.co [College of Maths and Systematic Science, Shenyang Normal University, Shenyang 110034 (China)

2011-03-14

From the super-matrix Lie algebras, we consider a super-extension of the CKdV equation hierarchy in the present Letter, and propose the super-CKdV hierarchy with self-consistent sources. Furthermore, we establish the infinitely many conservation laws for the integrable super-CKdV hierarchy.

Stellar Disk Truncations: HI Density and Dynamics

Science.gov (United States)

Trujillo, Ignacio; Bakos, Judit

2010-06-01

Using HI Nearby Galaxy Survey (THINGS) 21-cm observations of a sample of nearby (nearly face-on) galaxies we explore whether the stellar disk truncation phenomenon produces any signature either in the HI gas density and/or in the gas dynamics. Recent cosmological simulations suggest that the origin of the break on the surface brightness distribution is produced by the appearance of a warp at the truncation position. This warp should produce a flaring on the gas distribution increasing the velocity dispersion of the HI component beyond the break. We do not find, however, any evidence of this increase in the gas velocity dispersion profile.

Elastic constants of the hard disc system in the self-consistent free volume approximation

International Nuclear Information System (INIS)

Wojciechowski, K.W.

1990-09-01

Elastic moduli of the two dimensional hard disc crystal are determined exactly within the Kirkwood self-consistent free volume approximation and compared with the Monte Carlo simulation results. (author). 22 refs, 1 fig., 1 tab

Self-consistent electronic structure of the contracted tungsten (001) surface

International Nuclear Information System (INIS)

Posternak, M.; Krakauer, H.; Freeman, A.J.

1982-01-01

Self-consistent linearized-augmented-plane-wave energy-band studies using the warped muffin-tin approximation for a seven-layer W(001) single slab with the surface-layer separation contracted by 6% of the bulk interlayer spacing are reported. Surface electronic structure, local densities of states, generalized susceptibility for the surface, work function, and core-level shifts are found to have insignificant differences with corresponding results for the unrelaxed surface. Several differences in surface states between theory and recent angle-resolved photoemission experiments are discussed in the light of new proposed models of the actual unreconstructed surface structure at high temperatures

A self-consistent model for thermodynamics of multicomponent solid solutions

International Nuclear Information System (INIS)

Svoboda, J.; Fischer, F.D.

2016-01-01

The self-consistent concept recently published in this journal (108, 27–30, 2015) is extended from a binary to a multicomponent system. This is possible by exploiting the trapping concept as basis for including the interaction of atoms in terms of pairs (e.g. A–A, B–B, C–C…) and couples (e.g. A–B, B–C, …) in a multicomponent system with A as solvent and B, C, … as dilute solutes. The model results in a formulation of Gibbs-energy, which can be minimized. Examples show that the couple and pair formation may influence the equilibrium Gibbs energy markedly.

Self-consistent assessment of Englert-Schwinger model on atomic properties

Science.gov (United States)

Lehtomäki, Jouko; Lopez-Acevedo, Olga

2017-12-01

Our manuscript investigates a self-consistent solution of the statistical atom model proposed by Berthold-Georg Englert and Julian Schwinger (the ES model) and benchmarks it against atomic Kohn-Sham and two orbital-free models of the Thomas-Fermi-Dirac (TFD)-λvW family. Results show that the ES model generally offers the same accuracy as the well-known TFD-1/5 vW model; however, the ES model corrects the failure in the Pauli potential near-nucleus region. We also point to the inability of describing low-Z atoms as the foremost concern in improving the present model.

Miniaturized isothermal nucleic acid amplification, a review.

Science.gov (United States)

Asiello, Peter J; Baeumner, Antje J

2011-04-21

Micro-Total Analysis Systems (µTAS) for use in on-site rapid detection of DNA or RNA are increasingly being developed. Here, amplification of the target sequence is key to increasing sensitivity, enabling single-cell and few-copy nucleic acid detection. The several advantages to miniaturizing amplification reactions and coupling them with sample preparation and detection on the same chip are well known and include fewer manual steps, preventing contamination, and significantly reducing the volume of expensive reagents. To-date, the majority of miniaturized systems for nucleic acid analysis have used the polymerase chain reaction (PCR) for amplification and those systems are covered in previous reviews. This review provides a thorough overview of miniaturized analysis systems using alternatives to PCR, specifically isothermal amplification reactions. With no need for thermal cycling, isothermal microsystems can be designed to be simple and low-energy consuming and therefore may outperform PCR in portable, battery-operated detection systems in the future. The main isothermal methods as miniaturized systems reviewed here include nucleic acid sequence-based amplification (NASBA), loop-mediated isothermal amplification (LAMP), helicase-dependent amplification (HDA), rolling circle amplification (RCA), and strand displacement amplification (SDA). Also, important design criteria for the miniaturized devices are discussed. Finally, the potential of miniaturization of some new isothermal methods such as the exponential amplification reaction (EXPAR), isothermal and chimeric primer-initiated amplification of nucleic acids (ICANs), signal-mediated amplification of RNA technology (SMART) and others is presented.

Self-consistent theory of charged current neutrino-nucleus reactions

Energy Technology Data Exchange (ETDEWEB)

Paar, Nils; Marketin, Tomislav; Vretenar, Dario [Physics Department, Faculty of Science, University Zagreb (Croatia); Ring, Peter [Physik-Department, Technischen Universitaet Muenchen, D-85748 Muenchen (Germany)

2009-07-01

A novel theoretical framework has been introduced for description of neutrino induced reactions with nuclei. The properties of target nuclei are determined in a self-consistent way using relativistic mean-field framework based on effective Lagrangians with density dependent meson-nucleon vertex functions. The weak lepton-hadron interaction is expressed in the standard current-current form, the nuclear ground state is described in the relativistic Hartree-Bogolyubov model, and the relevant transitions to excited nuclear states are calculated in the proton-neutron relativistic quasiparticle random phase approximation. This framework has been employed in studies of charged-current neutrino reactions involving nuclei of relevance for neutrino detectors, r-process nuclei, and neutrino-nucleus cross sections averaged over measured neutrino fluxes and supernova neutrino distributions.

A new mixed self-consistent field procedure

Science.gov (United States)

Alvarez-Ibarra, A.; Köster, A. M.

2015-10-01

A new approach for the calculation of three-centre electronic repulsion integrals (ERIs) is developed, implemented and benchmarked in the framework of auxiliary density functional theory (ADFT). The so-called mixed self-consistent field (mixed SCF) divides the computationally costly ERIs in two sets: far-field and near-field. Far-field ERIs are calculated using the newly developed double asymptotic expansion as in the direct SCF scheme. Near-field ERIs are calculated only once prior to the SCF procedure and stored in memory, as in the conventional SCF scheme. Hence the name, mixed SCF. The implementation is particularly powerful when used in parallel architectures, since all RAM available are used for near-field ERI storage. In addition, the efficient distribution algorithm performs minimal intercommunication operations between processors, avoiding a potential bottleneck. One-, two- and three-dimensional systems are used for benchmarking, showing substantial time reduction in the ERI calculation for all of them. A Born-Oppenheimer molecular dynamics calculation for the Na+55 cluster is also shown in order to demonstrate the speed-up for small systems achievable with the mixed SCF. Dedicated to Sourav Pal on the occasion of his 60th birthday.

Diagnostic Devices for Isothermal Nucleic Acid Amplification

Directory of Open Access Journals (Sweden)

Chia-Chen Chang

2012-06-01

Full Text Available Since the development of the polymerase chain reaction (PCR technique, genomic information has been retrievable from lesser amounts of DNA than previously possible. PCR-based amplifications require high-precision instruments to perform temperature cycling reactions; further, they are cumbersome for routine clinical use. However, the use of isothermal approaches can eliminate many complications associated with thermocycling. The application of diagnostic devices for isothermal DNA amplification has recently been studied extensively. In this paper, we describe the basic concepts of several isothermal amplification approaches and review recent progress in diagnostic device development.

Diagnostic devices for isothermal nucleic acid amplification.

Science.gov (United States)

Chang, Chia-Chen; Chen, Chien-Cheng; Wei, Shih-Chung; Lu, Hui-Hsin; Liang, Yang-Hung; Lin, Chii-Wann

2012-01-01

Since the development of the polymerase chain reaction (PCR) technique, genomic information has been retrievable from lesser amounts of DNA than previously possible. PCR-based amplifications require high-precision instruments to perform temperature cycling reactions; further, they are cumbersome for routine clinical use. However, the use of isothermal approaches can eliminate many complications associated with thermocycling. The application of diagnostic devices for isothermal DNA amplification has recently been studied extensively. In this paper, we describe the basic concepts of several isothermal amplification approaches and review recent progress in diagnostic device development.

Enhancing propagation characteristics of truncated localized waves in silica

KAUST Repository

Salem, Mohamed

2011-07-01

The spectral characteristics of truncated Localized Waves propagating in dispersive silica are analyzed. Numerical experiments show that the immunity of the truncated Localized Waves propagating in dispersive silica to decay and distortion is enhanced as the non-linearity of the relation between the transverse spatial spectral components and the wave vector gets stronger, in contrast to free-space propagating waves, which suffer from early decay and distortion. © 2011 IEEE.

Microstructural evolution during isothermal aging and strain-induced transformation followed by isothermal aging in Co-Cr-Mo-C alloy: A comparative study

International Nuclear Information System (INIS)

Lashgari, H.R.; Zangeneh, Sh.; Hasanabadi, F.; Saghafi, M.

2010-01-01

The present study was undertaken to investigate the effects of isothermal aging (at 850 deg. C for 4, 8, 16 and 24 h) and strain-induced transformation (engineering strains of 10% and 20%) followed by isothermal aging (at 850 deg. C for 4, 8 and 16 h) on the microstructural evolution of a Co-28Cr-5Mo-0.3C alloy. The obtained results showed that isothermal aging at 850 deg. C resulted in the formation of lamellar-type carbides at the grain boundaries. Moreover, X-ray diffraction analysis indicated that isothermal aging of solution treated specimens at 850 deg. C for 24 h did not lead to complete fcc phase transformation to hcp one. In contrast with the isothermally aged specimens, applying plastic deformation to the solutionized samples accelerated the completion and saturation of fcc(metastable) → hcp transformation after 8 h aging at 850 deg. C. In addition, the X-ray diffraction results indicated that implementing isothermal aging of the strain-induced specimens at the higher aging time (16 h) caused the formation of (1 1 1) fcc and (2 0 0) fcc diffraction peaks again. Also, the strain-induced specimens followed by isothermal aging showed higher amount of microhardness as compared with the other specimens aged solely.

Convergence of quasiparticle self-consistent GW calculations of transition metal monoxides

OpenAIRE

Das, Suvadip; Coulter, John E.; Manousakis, Efstratios

2014-01-01

Finding an accurate ab initio approach for calculating the electronic properties of transition metal oxides has been a problem for several decades. In this paper, we investigate the electronic structure of the transition metal monoxides MnO, CoO, and NiO in their undistorted rock-salt structure within a fully iterated quasiparticle self-consistent GW (QPscGW) scheme. We study the convergence of the QPscGW method, i.e., how the quasiparticle energy eigenvalues and wavefunctions converge as a f...

Self-consistent particle distribution of a bunched beam in RF field

CERN Document Server

Batygin, Y K

2002-01-01

An analytical solution for the self-consistent particle equilibrium distribution in an RF field with transverse focusing is found. The solution is attained in the approximation of a high brightness beam. The distribution function in phase space is determined as a stationary function of the energy integral. Equipartitioning of the beam distribution between degrees of freedom follows directly from the choice of the stationary distribution function. Analytical expressions for r-z equilibrium beam profile and maximum beam current in RF field are obtained.

Self-consistent, relativistic, ferromagnetic band structure of gadolinium

International Nuclear Information System (INIS)

Harmon, B.N.; Schirber, J.; Koelling, D.D.

1977-01-01

An initial self-consistent calculation of the ground state magnetic band structure of gadolinium is described. A linearized APW method was used which included all single particle relativistic effects except spin-orbit coupling. The spin polarized potential was obtained in the muffin-tin form using the local spin density approximation for exchange and correlation. The most striking and unorthodox aspect of the results is the position of the 4f spin-down ''bands'' which are required to float just on top of the Fermi level in order to obtain convergence. If the 4f states (l = 3 resonance) are removed from the occupied region of the conduction bands the magnetic moment is approximately .75 μ/sub B//atom; however, as the 4f spin-down states are allowed to find their own position they hybridize with the conduction bands at the Fermi level and the moment becomes smaller. Means of improving the calculation are discussed

Self-consistent Analysis of Three-dimensional Uniformly Charged Ellipsoid with Zero Emittance

International Nuclear Information System (INIS)

Batygin, Yuri K.

2001-01-01

A self-consistent treatment of a three-dimensional ellipsoid with negligible emittance in time-dependent external field is performed. Envelope equations describing the evolution of an ellipsoid boundary are discussed. For a complete model it is required that the initial particle momenta be a linear function of the coordinates. Numerical example and verification of the problem by a 3-dimensional particle-in-cell simulations are given

Solving Non-Isospectral mKdV Equation and Sine-Gordon Equation Hierarchies with Self-Consistent Sources via Inverse Scattering Transform

International Nuclear Information System (INIS)

Li Qi; Zhang Dajun; Chen Dengyuan

2010-01-01

N-soliton solutions of the hierarchy of non-isospectral mKdV equation with self-consistent sources and the hierarchy of non-isospectral sine-Gordon equation with self-consistent sources are obtained via the inverse scattering transform. (general)

Isotherms clustering in cosmic microwave background

International Nuclear Information System (INIS)

Bershadskii, A.

2006-01-01

Isotherms clustering in cosmic microwave background (CMB) has been studied using the 3-year WMAP data on cosmic microwave background radiation. It is shown that the isotherms clustering could be produced by the baryon-photon fluid turbulence in the last scattering surface. The Taylor-microscale Reynolds number of the turbulence is estimated directly from the CMB data as Re λ ∼10 2

Truncation of CPC solar collectors and its effect on energy collection

Science.gov (United States)

Carvalho, M. J.; Collares-Pereira, M.; Gordon, J. M.; Rabl, A.

1985-01-01

Analytic expressions are derived for the angular acceptance function of two-dimensional compound parabolic concentrator solar collectors (CPC's) of arbitrary degree of truncation. Taking into account the effect of truncation on both optical and thermal losses in real collectors, the increase in monthly and yearly collectible energy is also evaluated. Prior analyses that have ignored the correct behavior of the angular acceptance function at large angles for truncated collectors are shown to be in error by 0-2 percent in calculations of yearly collectible energy for stationary collectors.

Water adsorption isotherms of carboxymethyl cellulose, guar, locust bean, tragacanth and xanthan gums.

Science.gov (United States)

Torres, María D; Moreira, Ramón; Chenlo, Francisco; Vázquez, María J

2012-06-20

Water adsorption isotherms of carboxymethyl cellulose (CMC), guar gum (GG), locust bean gum (LBG), tragacanth gum (TG) and xanthan gum (XG) were determined at different temperatures (20, 35, 50, and 65°C) using a gravimetric method. Several saturated salt solutions were selected to obtain different water activities in the range from 0.09 to 0.91. Water adsorption isotherms of tested hydrocolloids were classified like type II isotherms. In all cases, equilibrium moisture content decreased with increasing temperature at each water activity value. Three-parameter Guggenheim-Anderson-de Boer (GAB) model was employed to fit the experimental data in the water activity range and statistical analysis indicated that this model gave satisfactory results. CMC and GG were the most and the least hygroscopic gums, respectively. Sorption heats decreased with increasing moisture content. Monolayer moisture content evaluated with GAB model was consistent with equilibrium conditions of maximum stability calculated from thermodynamic analysis of net integral entropy. Values of equilibrium relative humidity at 20°C are proposed to storage adequately the tested gums. Copyright © 2012 Elsevier Ltd. All rights reserved.

Morphology and crystallographic orientation relationship in isothermally transformed Fe–N austenite

International Nuclear Information System (INIS)

Jiao, Dongling; Luo, Chengping; Liu, Jiangwen; Zhang, Guoqing

2014-01-01

The 225 °C isothermal transformation of a high-nitrogen austenite with Fe–2.71 wt.% N was investigated by means of electron microscopy. It was found that the transformation products were composed of ultrafine α-Fe and γ′-Fe 4 N plus retained austenite γ, which were in two types of morphologies, namely, (i) with the retained austenite patches dispersed among the (α-Fe + γ′-Fe 4 N) packets and (ii) with the ultrafine α-Fe and γ/γ′-Fe 4 N laths interwoven with each other within a single bainitic packet. A cube–cube orientation relationship between the γ (austenite) and γ′-Fe 4 N, and a near Greninger–Troiano (G–T) one between the γ (austenite) and the bainitic α-ferrite were detected. The morphology, orientation relationship and high hardness (> 1000 HV) of the transformation products indicated that the isothermal transformation of the high nitrogen austenite was analogous to a bainitic one. - Highlights: • Isothermal transformation products consisted of nano-sized α-Fe + γ′ + γ (retained). • The hardness of transformation product exceeded 1000 HV. • The α-Fe and γ/γ′-Fe 4 N kept a near G-T OR in the grain interior

Persistence length of wormlike micelles composed of ionic surfactants: self-consistent-field predictions

NARCIS (Netherlands)

Lauw, Y.; Leermakers, F.A.M.; Cohen Stuart, M.A.

2007-01-01

The persistence length of a wormlike micelle composed of ionic surfactants CnEmXk in an aqueous solvent is predicted by means of the self-consistent-field theory where CnEm is the conventional nonionic surfactant and X-k is an additional sequence of k weakly charged (pH-dependent) segments. By

Determining the baking isotherm temperature of Söderberg electrodes and associated structural changes

OpenAIRE

Shoko, L.; Beukes, J.P.; Strydom, C.A.

2013-01-01

One of the most commonly employed electrode systems in industrial metal smelting applications is continuous self-baking electrodes, i.e. the Söderberg electrode system. In this system, the temperature at which transition from a liquid/soft paste to a solid carbonaceous electrode takes place is termed the baking isotherm temperature. This temperature is extremely important within the context of electrode management. In this paper, thermo mechanical analysis (TMA) was used to measure the dimens...

Hardness of H13 Tool Steel After Non-isothermal Tempering

Science.gov (United States)

Nelson, E.; Kohli, A.; Poirier, D. R.

2018-04-01

A direct method to calculate the tempering response of a tool steel (H13) that exhibits secondary hardening is presented. Based on the traditional method of presenting tempering response in terms of isothermal tempering, we show that the tempering response for a steel undergoing a non-isothermal tempering schedule can be predicted. Experiments comprised (1) isothermal tempering, (2) non-isothermal tempering pertaining to a relatively slow heating to process-temperature and (3) fast-heating cycles that are relevant to tempering by induction heating. After establishing the tempering response of the steel under simple isothermal conditions, the tempering response can be applied to non-isothermal tempering by using a numerical method to calculate the tempering parameter. Calculated results are verified by the experiments.

Self-consistent finite-temperature model of atom-laser coherence properties

International Nuclear Information System (INIS)

Fergusson, J.R.; Geddes, A.J.; Hutchinson, D.A.W.

2005-01-01

We present a mean-field model of a continuous-wave atom laser with Raman output coupling. The noncondensate is pumped at a fixed input rate which, in turn, pumps the condensate through a two-body scattering process obeying the Fermi golden rule. The gas is then coupled out by a Gaussian beam from the system, and the temperature and particle number are self-consistently evaluated against equilibrium constraints. We observe the dependence of the second-order coherence of the output upon the width of the output-coupling beam, and note that even in the presence of a highly coherent trapped gas, perfect coherence of the output matter wave is not guaranteed

Branch-based model for the diameters of the pulmonary airways: accounting for departures from self-consistency and registration errors.

Science.gov (United States)

Neradilek, Moni B; Polissar, Nayak L; Einstein, Daniel R; Glenny, Robb W; Minard, Kevin R; Carson, James P; Jiao, Xiangmin; Jacob, Richard E; Cox, Timothy C; Postlethwait, Edward M; Corley, Richard A

2012-06-01

We examine a previously published branch-based approach for modeling airway diameters that is predicated on the assumption of self-consistency across all levels of the tree. We mathematically formulate this assumption, propose a method to test it and develop a more general model to be used when the assumption is violated. We discuss the effect of measurement error on the estimated models and propose methods that take account of error. The methods are illustrated on data from MRI and CT images of silicone casts of two rats, two normal monkeys, and one ozone-exposed monkey. Our results showed substantial departures from self-consistency in all five subjects. When departures from self-consistency exist, we do not recommend using the self-consistency model, even as an approximation, as we have shown that it may likely lead to an incorrect representation of the diameter geometry. The new variance model can be used instead. Measurement error has an important impact on the estimated morphometry models and needs to be addressed in the analysis. Copyright © 2012 Wiley Periodicals, Inc.

The role of collective self-gravity in the nonlinear evolution of viscous overstability in Saturn's rings.

Science.gov (United States)

Lehmann, Marius; Schmidt, Jürgen; Salo, Heikki

2017-06-01

We investigate the influence of collective self-gravity forces on the nonlinear evolution of the viscous overstability in Saturn's dense rings. Local N-body simulations, incorporating vertical and radial collective self-gravity are performed. Vertical self-gravity is mimicked through an increased frequency of vertical oscillations, while radial self-gravity is approximated by solving the Poisson equation for a thin disk in Fourier space. Direct particle-particle forces are omitted, while the magnitude of radial self gravity is controlled by assigning a variable surface mass density to the system's homogeneous ground state. We compare our simulations with large-scale isothermal and non-isothermal hydrodynamic model calculations, including radial self-gravity and employing transport coefficients derived in Salo et al. (2001). We concentrate on optical depths τ=1.5-2, appropriate to model Saturn's dense rings. Our isothermal and non isothermal hydrodynamic results in the limit of vanishing self-gravity compare very well with the studies of Latter&Ogilvie (2010) and Rein&latter (2013), respectively.With non-vanishing radial self-gravity we find that the wavelengths of saturated overstable wave trains are located in close vicinity of the local minimum of the nonlinear dispersion relation for a particular surface density. Good agreement is found between non-isothermal hydrodynamics and N-body simulations for disks with strong radial self-gravity, while the largest deviations occur for a weak but non-vanishing self-gravity.The resulting saturation wavelengths of the viscous overstability for moderate and strong radial self-gravity (λ~ 200-300m) agree reasonably well with the length scale of periodic micro structure in Saturn's inner A and B ring, as found by Cassini.

Calculating beta decay in the deformed self-consistent quasiparticle random phase approximation

Energy Technology Data Exchange (ETDEWEB)

Engel, Jonathan, E-mail: engelj@physics.unc.edu [Department of Physics and Astronomy, University of North Carolina, Chapel Hill, NC 27599-3255 (United States); Mustonen, M. T., E-mail: mika.mustonen@yale.edu [Department of Physics and Astronomy, University of North Carolina, Chapel Hill, NC 27599-3255 (United States); Center for Theoretical Physics, Sloane Physics Laboratory, Yale University, New Haven, CT 06052 (United States)

2016-06-21

We discuss a recent global calculation of beta-decay rates in the self-consistent Skyrme quasiparticle random phase approximation (QRPA), with axially symmetric nuclear deformation treated explicitly. The calculation makes makes use of the finite-amplitude method, first proposed by Nakatsukasa and collaborators, to reduce computation time. The results are comparable in quality to those of several other global QRPA calculations. The QRPA may have reached the limit of its accuracy.

Interpretation of Quasi-Isothermal Thermogravimetric Weight Curves

DEFF Research Database (Denmark)

Sørensen, Ole Toft

1979-01-01

Quasi-isothermal analysis (QIA) is a very useful technique. Compared to conventional non-isothermal thermogravimetry, close-lying reactions can easily be separated by use of this method and kinetic data can be obtained for each intermediate reaction in a single run. This paper discusses the shape...

Universality of isothermal fluid spheres in Lovelock gravity

Science.gov (United States)

Dadhich, Naresh; Hansraj, Sudan; Maharaj, Sunil D.

2016-02-01

We show universality of isothermal fluid spheres in pure Lovelock gravity where the equation of motion has only one N th order term coming from the corresponding Lovelock polynomial action of degree N . Isothermality is characterized by the equation of state, p =α ρ and the property, ρ ˜1 /r2 N . Then the solution describing isothermal spheres, which exist only for the pure Lovelock equation, is of the same form for the general Lovelock degree N in all dimensions d ≥2 N +2 . We further prove that the necessary and sufficient condition for the isothermal sphere is that its metric is conformal to the massless global monopole or the solid angle deficit metric, and this feature is also universal.

Transiently truncated and differentially regulated expression of midkine during mouse embryogenesis

International Nuclear Information System (INIS)

Chen Qin; Yuan Yuanyang; Lin Shuibin; Chang Youde; Zhuo Xinming; Wei Wei; Tao Ping; Ruan Lingjuan; Li Qifu; Li Zhixing

2005-01-01

Midkine (MK) is a retinoic acid response cytokine, mostly expressed in embryonic tissues. Aberrant expression of MK was found in numerous cancers. In human, a truncated MK was expressed specifically in tumor/cancer tissues. Here we report the discovery of a novel truncated form of MK transiently expressed during normal mouse embryonic development. In addition, MK is concentrated at the interface between developing epithelium and mesenchyme as well as highly proliferating cells. Its expression, which is closely coordinated with angiogenesis and vasculogenesis, is spatiotemporally regulated with peaks in extensive organogenesis period and undifferentiated cells tailing off in maturing cells, implying its role in nascent blood vessel (endothelial) signaling of tissue differentiation and stem cell renewal/differentiation.. Cloning and sequencing analysis revealed that the embryonic truncated MK, in which the conserved domain is in-frame deleted, presumably producing a novel secreted small peptide, is different from the truncated form in human cancer tissues, whose deletion results in a frame-shift mutation. Our data suggest that MK may play a role in epithelium-mesenchyme interactions, blood vessel signaling, and the decision of proliferation vs differentiation. Detection of the transiently expressed truncated MK reveals its novel function in development and sheds light on its role in carcinogenesis

A Simulation Model for Drift Resistive Ballooning Turbulence Examining the Influence of Self-consistent Zonal Flows

Science.gov (United States)

Cohen, Bruce; Umansky, Maxim; Joseph, Ilon

2015-11-01

Progress is reported on including self-consistent zonal flows in simulations of drift-resistive ballooning turbulence using the BOUT + + framework. Previous published work addressed the simulation of L-mode edge turbulence in realistic single-null tokamak geometry using the BOUT three-dimensional fluid code that solves Braginskii-based fluid equations. The effects of imposed sheared ExB poloidal rotation were included, with a static radial electric field fitted to experimental data. In new work our goal is to include the self-consistent effects on the radial electric field driven by the microturbulence, which contributes to the sheared ExB poloidal rotation (zonal flow generation). We describe a model for including self-consistent zonal flows and an algorithm for maintaining underlying plasma profiles to enable the simulation of steady-state turbulence. We examine the role of Braginskii viscous forces in providing necessary dissipation when including axisymmetric perturbations. We also report on some of the numerical difficulties associated with including the axisymmetric component of the fluctuating fields. This work was performed under the auspices of the U.S. Department of Energy under contract DE-AC52-07NA27344 at the Lawrence Livermore National Laboratory (LLNL-ABS-674950).

Modifications of Geometric Truncation of the Scattering Phase Function

Science.gov (United States)

Radkevich, A.

2017-12-01

Phase function (PF) of light scattering on large atmospheric particles has very strong peak in forward direction constituting a challenge for accurate numerical calculations of radiance. Such accurate (and fast) evaluations are important in the problems of remote sensing of the atmosphere. Scaling transformation replaces original PF with a sum of the delta function and a new regular smooth PF. A number of methods to construct such a PF were suggested. Delta-M and delta-fit methods require evaluation of the PF moments which imposes a numerical problem if strongly anisotropic PF is given as a function of angle. Geometric truncation keeps the original PF unchanged outside the forward peak cone replacing it with a constant within the cone. This approach is designed to preserve the asymmetry parameter. It has two disadvantages: 1) PF has discontinuity at the cone; 2) the choice of the cone is subjective, no recommendations were provided on the choice of the truncation angle. This choice affects both truncation fraction and the value of the phase function within the forward cone. Both issues are addressed in this study. A simple functional form of the replacement PF is suggested. This functional form allows for a number of modifications. This study consider 3 versions providing continuous PF. The considered modifications also bear either of three properties: preserve asymmetry parameter, provide continuity of the 1st derivative of the PF, and preserve mean scattering angle. The second problem mentioned above is addressed with a heuristic approach providing unambiguous criterion of selection of the truncation angle. The approach showed good performance on liquid water and ice clouds with different particle size distributions. Suggested modifications were tested on different cloud PFs using both discrete ordinates and Monte Carlo methods. It was showed that the modifications provide better accuracy of the radiance computation compare to the original geometric truncation.

Ptychographic x-ray imaging of surfaces on crystal truncation rod

Energy Technology Data Exchange (ETDEWEB)

Zhu, Chenhui; Barbour, Andi; Liu, Yaohua; You, Hoydoo, E-mail: hyou@anl.gov [Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Harder, Ross; Xu, Ruqing [Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Diaz, Ana; Menzel, Andreas [Paul Scherrer Institut, Villigen PSI 5232 (Switzerland); Komanicky, Vladimir [Faculty of Sciences, Safarik University, Kosice 04154 (Slovakia); Huang, Xiaojing [National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, New York 11973 (United States); Pierce, Michael S. [School of Physics and Astronomy, Rochester Institute of Technology, Rochester, New York 14623 (United States)

2015-03-09

Ptychography is a high-resolution imaging technique, which does not require lenses for image magnification and which provides phase contrast with high sensitivity. Here, we propose to use x-ray ptychography for the imaging of surface structure in crystalline samples. We show that ptychography can be used to image atomic step structures using coherent diffraction patterns recorded along the crystal truncation rod of a crystal surface. In a proof-of-concept experiment on a Pt (111) sample, we present ptychographic reconstructions showing features consistent with surface steps. Due to the penetration power of x-rays, this method could find interesting applications for the study of surface structures under buried interfaces or in harsh environments.

Ptychographic x-ray imaging of surfaces on crystal truncation rod

International Nuclear Information System (INIS)

Zhu, Chenhui; Barbour, Andi; Liu, Yaohua; You, Hoydoo; Harder, Ross; Xu, Ruqing; Diaz, Ana; Menzel, Andreas; Komanicky, Vladimir; Huang, Xiaojing; Pierce, Michael S.

2015-01-01

Ptychography is a high-resolution imaging technique, which does not require lenses for image magnification and which provides phase contrast with high sensitivity. Here, we propose to use x-ray ptychography for the imaging of surface structure in crystalline samples. We show that ptychography can be used to image atomic step structures using coherent diffraction patterns recorded along the crystal truncation rod of a crystal surface. In a proof-of-concept experiment on a Pt (111) sample, we present ptychographic reconstructions showing features consistent with surface steps. Due to the penetration power of x-rays, this method could find interesting applications for the study of surface structures under buried interfaces or in harsh environments

Bounds and self-consistent estimates for elastic constants of granular polycrystals composed of orthorhombics or crystal with higher symmetries

Energy Technology Data Exchange (ETDEWEB)

Berryman, J. G.

2011-02-01

Methods for computing Hashin-Shtrikman bounds and related self-consistent estimates of elastic constants for polycrystals composed of crystals having orthorhombic symmetry have been known for about three decades. However, these methods are underutilized, perhaps because of some perceived difficulties with implementing the necessary computational procedures. Several simplifications of these techniques are introduced, thereby reducing the overall computational burden, as well as the complications inherent in mapping out the Hashin-Shtrikman bounding curves. The self-consistent estimates of the effective elastic constants are very robust, involving a quickly converging iteration procedure. Once these self-consistent values are known, they may then be used to speed up the computations of the Hashin-Shtrikman bounds themselves. It is shown furthermore that the resulting orthorhombic polycrystal code can be used as well to compute both bounds and self-consistent estimates for polycrystals of higher-symmetry tetragonal, hexagonal, and cubic (but not trigonal) materials. The self-consistent results found this way are shown to be the same as those obtained using the earlier methods, specifically those methods designed specially for each individual symmetry type. But the Hashin-Shtrikman bounds found using the orthorhombic code are either the same or (more typically) tighter than those found previously for these special cases (i.e., tetragonal, hexagonal, and cubic). The improvement in the Hashin-Shtrikman bounds is presumably due to the additional degrees of freedom introduced into the available search space.

Self consistent field theory of virus assembly

Science.gov (United States)

Li, Siyu; Orland, Henri; Zandi, Roya

2018-04-01

The ground state dominance approximation (GSDA) has been extensively used to study the assembly of viral shells. In this work we employ the self-consistent field theory (SCFT) to investigate the adsorption of RNA onto positively charged spherical viral shells and examine the conditions when GSDA does not apply and SCFT has to be used to obtain a reliable solution. We find that there are two regimes in which GSDA does work. First, when the genomic RNA length is long enough compared to the capsid radius, and second, when the interaction between the genome and capsid is so strong that the genome is basically localized next to the wall. We find that for the case in which RNA is more or less distributed uniformly in the shell, regardless of the length of RNA, GSDA is not a good approximation. We observe that as the polymer-shell interaction becomes stronger, the energy gap between the ground state and first excited state increases and thus GSDA becomes a better approximation. We also present our results corresponding to the genome persistence length obtained through the tangent-tangent correlation length and show that it is zero in case of GSDA but is equal to the inverse of the energy gap when using SCFT.

A self-consistent upward leader propagation model

International Nuclear Information System (INIS)

Becerra, Marley; Cooray, Vernon

2006-01-01

The knowledge of the initiation and propagation of an upward moving connecting leader in the presence of a downward moving lightning stepped leader is a must in the determination of the lateral attraction distance of a lightning flash by any grounded structure. Even though different models that simulate this phenomenon are available in the literature, they do not take into account the latest developments in the physics of leader discharges. The leader model proposed here simulates the advancement of positive upward leaders by appealing to the presently understood physics of that process. The model properly simulates the upward continuous progression of the positive connecting leaders from its inception to the final connection with the downward stepped leader (final jump). Thus, the main physical properties of upward leaders, namely the charge per unit length, the injected current, the channel gradient and the leader velocity are self-consistently obtained. The obtained results are compared with an altitude triggered lightning experiment and there is good agreement between the model predictions and the measured leader current and the experimentally inferred spatial and temporal location of the final jump. It is also found that the usual assumption of constant charge per unit length, based on laboratory experiments, is not valid for lightning upward connecting leaders

A Support Vector Machine Approach for Truncated Fingerprint Image Detection from Sweeping Fingerprint Sensors

Science.gov (United States)

Chen, Chi-Jim; Pai, Tun-Wen; Cheng, Mox

2015-01-01

A sweeping fingerprint sensor converts fingerprints on a row by row basis through image reconstruction techniques. However, a built fingerprint image might appear to be truncated and distorted when the finger was swept across a fingerprint sensor at a non-linear speed. If the truncated fingerprint images were enrolled as reference targets and collected by any automated fingerprint identification system (AFIS), successful prediction rates for fingerprint matching applications would be decreased significantly. In this paper, a novel and effective methodology with low time computational complexity was developed for detecting truncated fingerprints in a real time manner. Several filtering rules were implemented to validate existences of truncated fingerprints. In addition, a machine learning method of supported vector machine (SVM), based on the principle of structural risk minimization, was applied to reject pseudo truncated fingerprints containing similar characteristics of truncated ones. The experimental result has shown that an accuracy rate of 90.7% was achieved by successfully identifying truncated fingerprint images from testing images before AFIS enrollment procedures. The proposed effective and efficient methodology can be extensively applied to all existing fingerprint matching systems as a preliminary quality control prior to construction of fingerprint templates. PMID:25835186

A Support Vector Machine Approach for Truncated Fingerprint Image Detection from Sweeping Fingerprint Sensors

Directory of Open Access Journals (Sweden)

Chi-Jim Chen

2015-03-01

Full Text Available A sweeping fingerprint sensor converts fingerprints on a row by row basis through image reconstruction techniques. However, a built fingerprint image might appear to be truncated and distorted when the finger was swept across a fingerprint sensor at a non-linear speed. If the truncated fingerprint images were enrolled as reference targets and collected by any automated fingerprint identification system (AFIS, successful prediction rates for fingerprint matching applications would be decreased significantly. In this paper, a novel and effective methodology with low time computational complexity was developed for detecting truncated fingerprints in a real time manner. Several filtering rules were implemented to validate existences of truncated fingerprints. In addition, a machine learning method of supported vector machine (SVM, based on the principle of structural risk minimization, was applied to reject pseudo truncated fingerprints containing similar characteristics of truncated ones. The experimental result has shown that an accuracy rate of 90.7% was achieved by successfully identifying truncated fingerprint images from testing images before AFIS enrollment procedures. The proposed effective and efficient methodology can be extensively applied to all existing fingerprint matching systems as a preliminary quality control prior to construction of fingerprint templates.

Pathological behavior of the open-shell restricted self-consistent-field equations

International Nuclear Information System (INIS)

Moscardo, F.; Alvarez-Collado, J.R.

1979-01-01

The possible solutions of open-shell restricted self-consistent-field equations for a doublet are studied for Li and Na atoms, according to the values of the parameters implied in those equations. A similar behavior, characterized by the presence of several variational solutions is observed in both atoms. Some of these solutions can be assigned to excited configurations. Excitation energies are in good agreement with experimental data. Doublet stability for the solutions obtained has been studied, discussing the saddle-point character present in those solutions associated to excited configurations

Pathological behavior of the open-shell restricted self-consistent-field equations

Energy Technology Data Exchange (ETDEWEB)

Moscardo, F.; Alvarez-Collado, J.R.

1979-02-01

The possible solutions of open-shell restricted self-consistent-field equations for a doublet are studied for Li and Na atoms, according to the values of the parameters implied in those equations. A similar behavior, characterized by the presence of several variational solutions is observed in both atoms. Some of these solutions can be assigned to excited configurations. Excitation energies are in good agreement with experimental data. Doublet stability for the solutions obtained has been studied, discussing the saddle-point character present in those solutions associated to excited configurations.

Resonance shifts and spill-out effects in self-consistent hydrodynamic nanoplasmonics

DEFF Research Database (Denmark)

Toscano, Giuseppe; Straubel, Jakob; Kwiatkowski, Alexander

2015-01-01

The standard hydrodynamic Drude model with hard-wall boundary conditions can give accurate quantitative predictions for the optical response of noble-metal nanoparticles. However, it is less accurate for other metallic nanosystems, where surface effects due to electron density spill-out in free...... space cannot be neglected. Here we address the fundamental question whether the description of surface effects in plasmonics necessarily requires a fully quantum-mechanical ab initio approach. We present a self-consistent hydrodynamic model (SC-HDM), where both the ground state and the excited state...

Propagation of truncated modified Laguerre-Gaussian beams

Science.gov (United States)

Deng, D.; Li, J.; Guo, Q.

2010-01-01

By expanding the circ function into a finite sum of complex Gaussian functions and applying the Collins formula, the propagation of hard-edge diffracted modified Laguerre-Gaussian beams (MLGBs) through a paraxial ABCD system is studied, and the approximate closed-form propagation expression of hard-edge diffracted MLGBs is obtained. The transverse intensity distribution of the MLGB carrying finite power can be characterized by a single bright and symmetric ring during propagation when the aperture radius is very large. Starting from the definition of the generalized truncated second-order moments, the beam quality factor of MLGBs through a hard-edged circular aperture is investigated in a cylindrical coordinate system, which turns out to be dependent on the truncated radius and the beam orders.

Enriching Elementary Quantum Mechanics with the Computer: Self-Consistent Field Problems in One Dimension

Science.gov (United States)

Bolemon, Jay S.; Etzold, David J.

1974-01-01

Discusses the use of a small computer to solve self-consistent field problems of one-dimensional systems of two or more interacting particles in an elementary quantum mechanics course. Indicates that the calculation can serve as a useful introduction to the iterative technique. (CC)

Balanced truncation for linear switched systems

DEFF Research Database (Denmark)

Petreczky, Mihaly; Wisniewski, Rafal; Leth, John-Josef

2013-01-01

In this paper, we present a theoretical analysis of the model reduction algorithm for linear switched systems from Shaker and Wisniewski (2011, 2009) and . This algorithm is a reminiscence of the balanced truncation method for linear parameter varying systems (Wood et al., 1996) [3]. Specifically...

Isothermal thermogravimetric data acquisition analysis system

Science.gov (United States)

Cooper, Kenneth, Jr.

1991-01-01

The description of an Isothermal Thermogravimetric Analysis (TGA) Data Acquisition System is presented. The system consists of software and hardware to perform a wide variety of TGA experiments. The software is written in ANSI C using Borland's Turbo C++. The hardware consists of a 486/25 MHz machine with a Capital Equipment Corp. IEEE488 interface card. The interface is to a Hewlett Packard 3497A data acquisition system using two analog input cards and a digital actuator card. The system provides for 16 TGA rigs with weight and temperature measurements from each rig. Data collection is conducted in three phases. Acquisition is done at a rapid rate during initial startup, at a slower rate during extended data collection periods, and finally at a fast rate during shutdown. Parameters controlling the rate and duration of each phase are user programmable. Furnace control (raising and lowering) is also programmable. Provision is made for automatic restart in the event of power failure or other abnormal terminations. Initial trial runs were conducted to show system stability.

Truncated Newton-Raphson Methods for Quasicontinuum Simulations

National Research Council Canada - National Science Library

Liang, Yu; Kanapady, Ramdev; Chung, Peter W

2006-01-01

.... In this research, we report the effectiveness of the truncated Newton-Raphson method and quasi-Newton method with low-rank Hessian update strategy that are evaluated against the full Newton-Raphson...

Generalized Lagrangian Jacobi Gauss collocation method for solving unsteady isothermal gas through a micro-nano porous medium

Science.gov (United States)

Parand, Kourosh; Latifi, Sobhan; Delkhosh, Mehdi; Moayeri, Mohammad M.

2018-01-01

In the present paper, a new method based on the Generalized Lagrangian Jacobi Gauss (GLJG) collocation method is proposed. The nonlinear Kidder equation, which explains unsteady isothermal gas through a micro-nano porous medium, is a second-order two-point boundary value ordinary differential equation on the unbounded interval [0, ∞). Firstly, using the quasilinearization method, the equation is converted to a sequence of linear ordinary differential equations. Then, by using the GLJG collocation method, the problem is reduced to solving a system of algebraic equations. It must be mentioned that this equation is solved without domain truncation and variable changing. A comparison with some numerical solutions made and the obtained results indicate that the presented solution is highly accurate. The important value of the initial slope, y'(0), is obtained as -1.191790649719421734122828603800159364 for η = 0.5. Comparing to the best result obtained so far, it is accurate up to 36 decimal places.

Self-consistent electronic structure of a model stage-1 graphite acceptor intercalate

International Nuclear Information System (INIS)

Campagnoli, G.; Tosatti, E.

1981-04-01

A simple but self-consistent LCAO scheme is used to study the π-electronic structure of an idealized stage-1 ordered graphite acceptor intercalate, modeled approximately on C 8 AsF 5 . The resulting non-uniform charge population within the carbon plane, band structure, optical and energy loss properties are discussed and compared with available spectroscopic evidence. The calculated total energy is used to estimate migration energy barriers, and the intercalate vibration mode frequency. (author)

The Stars and Gas in Outer Parts of Galaxy Disks : Extended or Truncated, Flat or Warped?

NARCIS (Netherlands)

van der Kruit, P. C.; Funes, JG; Corsini, EM

2008-01-01

I review observations of truncations of stellar disks and models for their origin, compare observations of truncations in moderately inclined galaxies to those in edge-on systems and discuss the relation between truncations and H I-warps and their systematics and origin. Truncations are a common

On truncated Taylor series and the position of their spurious zeros

DEFF Research Database (Denmark)

Christiansen, Søren; Madsen, Per A.

2006-01-01

A truncated Taylor series, or a Taylor polynomial, which may appear when treating the motion of gravity water waves, is obtained by truncating an infinite Taylor series for a complex, analytical function. For such a polynomial the position of the complex zeros is considered in case the Taylor...

Self-consistent Hartree-Fock RPA calculations in 208Pb

Science.gov (United States)

Taqi, Ali H.; Ali, Mohammed S.

2018-01-01

The nuclear structure of 208Pb is studied in the framework of the self-consistent random phase approximation (SCRPA). The Hartree-Fock mean field and single particle states are used to implement a completely SCRPA with Skyrme-type interactions. The Hamiltonian is diagonalised within a model space using five Skyrme parameter sets, namely LNS, SkI3, SkO, SkP and SLy4. In view of the huge number of the existing Skyrme-force parameterizations, the question remains which of them provide the best description of data. The approach attempts to accurately describe the structure of the spherical even-even nucleus 208Pb. To illustrate our approach, we compared the binding energy, charge density distribution, excitation energy levels scheme with the available experimental data. Moreover, we calculated isoscalar and isovector monopole, dipole, and quadrupole transition densities and strength functions.

Correlations between chaos in a perturbed sine-Gordon equation and a truncated model system

International Nuclear Information System (INIS)

Bishop, A.R.; Flesch, R.; Forests, M.G.; Overman, E.A.

1990-01-01

The purpose of this paper is to present a first step toward providing coordinates and associated dynamics for low-dimensional attractors in nearly integrable partial differential equations (pdes), in particular, where the truncated system reflects salient geometric properties of the pde. This is achieved by correlating: (1) numerical results on the bifurcations to temporal chaos with spatial coherence of the damped, periodically forced sine-Gordon equation with periodic boundary conditions; (2) an interpretation of the spatial and temporal bifurcation structures of this perturbed integrable system with regard to the exact structure of the sine-Gordon phase space; (3) a model dynamical systems problem, which is itself a perturbed integrable Hamiltonian system, derived from the perturbed sine-Gordon equation by a finite mode Fourier truncation in the nonlinear Schroedinger limit; and (4) the bifurcations to chaos in the truncated phase space. In particular, a potential source of chaos in both the pde and the model ordinary differential equation systems is focused on: the existence of homoclinic orbits in the unperturbed integrable phase space and their continuation in the perturbed problem. The evidence presented here supports the thesis that the chaotic attractors of the weakly perturbed periodic sine-Gordon system consists of low-dimensional metastable attacking states together with intermediate states that are O(1) unstable and correspond to homoclinic states in the integrable phase space. It is surmised that the chaotic dynamics on these attractors is due to the perturbation of these homocline integrable configurations

Self-Consistent Study of Conjugated Aromatic Molecular Transistors

International Nuclear Information System (INIS)

Jing, Wang; Yun-Ye, Liang; Hao, Chen; Peng, Wang; Note, R.; Mizuseki, H.; Kawazoe, Y.

2010-01-01

We study the current through conjugated aromatic molecular transistors modulated by a transverse field. The self-consistent calculation is realized with density function theory through the standard quantum chemistry software Gaussian03 and the non-equilibrium Green's function formalism. The calculated I – V curves controlled by the transverse field present the characteristics of different organic molecular transistors, the transverse field effect of which is improved by the substitutions of nitrogen atoms or fluorine atoms. On the other hand, the asymmetry of molecular configurations to the axis connecting two sulfur atoms is in favor of realizing the transverse field modulation. Suitably designed conjugated aromatic molecular transistors possess different I – V characteristics, some of them are similar to those of metal-oxide-semiconductor field-effect transistors (MOSFET). Some of the calculated molecular devices may work as elements in graphene electronics. Our results present the richness and flexibility of molecular transistors, which describe the colorful prospect of next generation devices. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

LIDT-DD: A New Self-Consistent Debris Disc Model Including Radiation Pressure and Coupling Dynamical and Collisional Evolution

Science.gov (United States)

Kral, Q.; Thebault, P.; Charnoz, S.

2014-01-01

The first attempt at developing a fully self-consistent code coupling dynamics and collisions to study debris discs (Kral et al. 2013) is presented. So far, these two crucial mechanisms were studied separately, with N-body and statistical collisional codes respectively, because of stringent computational constraints. We present a new model named LIDT-DD which is able to follow over long timescales the coupled evolution of dynamics (including radiation forces) and collisions in a self-consistent way.

Effects of self-consistency in a Green's function description of saturation in nuclear matter

International Nuclear Information System (INIS)

Dewulf, Y.; Neck, D. van; Waroquier, M.

2002-01-01

The binding energy in nuclear matter is evaluated within the framework of self-consistent Green's function theory, using a realistic nucleon-nucleon interaction. The two-body dynamics is solved at the level of summing particle-particle and hole-hole ladders. We go beyond the on-shell approximation and use intermediary propagators with a discrete-pole structure. A three-pole approximation is used, which provides a good representation of the quasiparticle excitations, as well as reproducing the zeroth- and first-order energy-weighted moments in both the nucleon removal and addition domains of the spectral function. Results for the binding energy are practically independent of the details of the discretization scheme. The main effect of the increased self-consistency is to introduce an additional density dependence, which causes a shift towards lower densities and smaller binding energies, as compared to a (continuous choice) Brueckner calculation with the same interaction. Particle number conservation and the Hugenholz-Van Hove theorem are satisfied with reasonable accuracy

Self-consistent perturbation expansion for Bose-Einstein condensates satisfying Goldstone's theorem and conservation laws

International Nuclear Information System (INIS)

Kita, Takafumi

2009-01-01

Quantum-field-theoretic descriptions of interacting condensed bosons have suffered from the lack of self-consistent approximation schemes satisfying Goldstone's theorem and dynamical conservation laws simultaneously. We present a procedure to construct such approximations systematically by using either an exact relation for the interaction energy or the Hugenholtz-Pines relation to express the thermodynamic potential in a Luttinger-Ward form. Inspection of the self-consistent perturbation expansion up to the third order with respect to the interaction shows that the two relations yield a unique identical result at each order, reproducing the conserving-gapless mean-field theory [T. Kita, J. Phys. Soc. Jpn. 74, 1891 (2005)] as the lowest-order approximation. The uniqueness implies that the series becomes exact when infinite terms are retained. We also derive useful expressions for the entropy and superfluid density in terms of Green's function and a set of real-time dynamical equations to describe thermalization of the condensate.

Surface self-diffusion of adatom on Pt cluster with truncated octahedron structure

Energy Technology Data Exchange (ETDEWEB)

Yang Jianyu, E-mail: wuliyangjianyu@yahoo.com.c [Department of Maths and Physics, Hunan Institute of Engineering, Xiangtan 411104 (China); Hu Wangyu, E-mail: wangyuhu2001@yahoo.com.c [Department of Applied Physics, Hunan University, Changsha 410082 (China); Chen Shuguang [Department of Applied Physics, Hunan University, Changsha 410082 (China)

2010-05-03

Surface diffusion of single Pt adatom on Pt cluster with truncated octahedron structure is investigated through a combination of molecular dynamics and nudged elastic band method. Using an embedded atom method to describe the atomic interactions, the minimum energy paths are determined and the energy barriers for adatom diffusion across and along step are evaluated. The diffusion of adatom crossing step edge between {l_brace}111{r_brace} and {l_brace}100{r_brace} facets has a surprisingly low barrier of 0.03 eV, which is 0.12 eV lower than the barrier for adatom diffusion from {l_brace}111{r_brace} to neighboring {l_brace}111{r_brace} facet. Owing to the small barrier of adatom diffusion across the step edge between {l_brace}111{r_brace} and {l_brace}100{r_brace} facets, the diffusion of adatom along the step edge cannot occur. The molecular dynamics simulations at low temperatures also support these results. Our results show that mass transport will prefer step with {l_brace}100{r_brace} microfacet and the Pt clusters can have only {l_brace}111{r_brace} facets in epitaxial growth.

Thermal degradation and isothermal crystalline behavior of poly(trimethylene terephthalate)

Institute of Scientific and Technical Information of China (English)

Jian Liu; Shu Guang Bian; Min Xiao; Shuan Jin Wang; Yue Zhong Meng

2009-01-01

Poly(trimethylene terephthalate)(PTT)is an excellent fiber material.Its thermal degradation and isothermal crystalline behaviors were in this study investigated using thermogravimetric analysis(TGA),thermogravimetric analysis-Fourier transform infrared spectroscopy(TGA-FTIR)analysis,differential scanning calorimetry(DSC)and X-ray diffraction(XRD).The thermal degradation mechanism of PTT follows Mclafferty rearrangement principle.The PTT with intrinsicviscosity(IV)of 0.74 dL/g has a maximum crystallinity of about 55%at 190℃,as demonstrated by DSC and XRD measurements consistently.

A review of 20 Ne structure in a full microscopic self-consistent shell ...

African Journals Online (AJOL)

A set of single-particle energies together with a set of two-body matrix- elements derived in a self –consistent manner from the Reid soft–core potential are used to calculate the energy levels of 20Ne. We used a harmonic oscillator wave function folded with two-body correlation functions in our calculation. It is found that the ...

Closed-form kinetic parameter estimation solution to the truncated data problem

International Nuclear Information System (INIS)

Zeng, Gengsheng L; Kadrmas, Dan J; Gullberg, Grant T

2010-01-01

In a dedicated cardiac single photon emission computed tomography (SPECT) system, the detectors are focused on the heart and the background is truncated in the projections. Reconstruction using truncated data results in biased images, leading to inaccurate kinetic parameter estimates. This paper has developed a closed-form kinetic parameter estimation solution to the dynamic emission imaging problem. This solution is insensitive to the bias in the reconstructed images that is caused by the projection data truncation. This paper introduces two new ideas: (1) it includes background bias as an additional parameter to estimate, and (2) it presents a closed-form solution for compartment models. The method is based on the following two assumptions: (i) the amount of the bias is directly proportional to the truncated activities in the projection data, and (ii) the background concentration is directly proportional to the concentration in the myocardium. In other words, the method assumes that the image slice contains only the heart and the background, without other organs, that the heart is not truncated, and that the background radioactivity is directly proportional to the radioactivity in the blood pool. As long as the background activity can be modeled, the proposed method is applicable regardless of the number of compartments in the model. For simplicity, the proposed method is presented and verified using a single compartment model with computer simulations using both noiseless and noisy projections.

Analytic reconstruction algorithms for triple-source CT with horizontal data truncation

International Nuclear Information System (INIS)

Chen, Ming; Yu, Hengyong

2015-01-01

Purpose: This paper explores a triple-source imaging method with horizontal data truncation to enlarge the field of view (FOV) for big objects. Methods: The study is conducted by using theoretical analysis, mathematical deduction, and numerical simulations. The proposed algorithms are implemented in c + + and MATLAB. While the basic platform is constructed in MATLAB, the computationally intensive segments are coded in c + +, which are linked via a MEX interface. Results: A triple-source circular scanning configuration with horizontal data truncation is developed, where three pairs of x-ray sources and detectors are unevenly distributed on the same circle to cover the whole imaging object. For this triple-source configuration, a fan-beam filtered backprojection-type algorithm is derived for truncated full-scan projections without data rebinning. The algorithm is also extended for horizontally truncated half-scan projections and cone-beam projections in a Feldkamp-type framework. Using their method, the FOV is enlarged twofold to threefold to scan bigger objects with high speed and quality. The numerical simulation results confirm the correctness and effectiveness of the developed algorithms. Conclusions: The triple-source scanning configuration with horizontal data truncation cannot only keep most of the advantages of a traditional multisource system but also cover a larger FOV for big imaging objects. In addition, because the filtering is shift-invariant, the proposed algorithms are very fast and easily parallelized on graphic processing units

The kinetic of mass loss of grades A and B of melted TNT by isothermal and non-isothermal gravimetric methods

Directory of Open Access Journals (Sweden)

Hamid Reza Pouretedal

2018-04-01

Full Text Available The kinetic and activation energy of mass loss of two grades of melted TNT explosive, grade A and grade B, with freezing points of 80.57 and 78.15 °C, respectively, were studied by isothermal and non-isothermal gravimetric methods. In isothermal method, the mass loss of samples in containers of glass and aluminum was followed in temperatures of 80, 90 and 100 °C. The kinetic of the mass loss of the samples in the aluminum container was higher than the kinetic of it in the glass container that can be related to the effects of heat transfer and catalytic of aluminum metal. Also, the presence of impurities in grade B was due to increasing of kinetic of mass loss of it versus grade A. The non-isothermal curves were obtained in range of 30–330 °C at heating rates of 10, 15 and 20 °C⋅min−1. The TG/DTG data were used for determination of activation energy (Ea of mass loss of TNT samples upon degradation by using Ozawa, Kissinger, Ozawa-Flynn-Wall (OFW and Kissinger-Akahira-Sunose (KAS methods as model free methods. The activation energies of grades of A and B of TNT was obtained 99–120 and 66–70 kJ mol−1, respectively. The lower values of activation energy of the degradation reaction of grade B confirm the effect of impurities in the kinetics of mass loss of this grade. Keywords: TNT, Isothermal, Non-isothermal, Kinetic, Mass loss

Self-consistent clustering analysis: an efficient multiscale scheme for inelastic heterogeneous materials

Energy Technology Data Exchange (ETDEWEB)

Liu, Z.; Bessa, M. A.; Liu, W.K.

2017-10-25

A predictive computational theory is shown for modeling complex, hierarchical materials ranging from metal alloys to polymer nanocomposites. The theory can capture complex mechanisms such as plasticity and failure that span across multiple length scales. This general multiscale material modeling theory relies on sound principles of mathematics and mechanics, and a cutting-edge reduced order modeling method named self-consistent clustering analysis (SCA) [Zeliang Liu, M.A. Bessa, Wing Kam Liu, “Self-consistent clustering analysis: An efficient multi-scale scheme for inelastic heterogeneous materials,” Comput. Methods Appl. Mech. Engrg. 306 (2016) 319–341]. SCA reduces by several orders of magnitude the computational cost of micromechanical and concurrent multiscale simulations, while retaining the microstructure information. This remarkable increase in efficiency is achieved with a data-driven clustering method. Computationally expensive operations are performed in the so-called offline stage, where degrees of freedom (DOFs) are agglomerated into clusters. The interaction tensor of these clusters is computed. In the online or predictive stage, the Lippmann-Schwinger integral equation is solved cluster-wise using a self-consistent scheme to ensure solution accuracy and avoid path dependence. To construct a concurrent multiscale model, this scheme is applied at each material point in a macroscale structure, replacing a conventional constitutive model with the average response computed from the microscale model using just the SCA online stage. A regularized damage theory is incorporated in the microscale that avoids the mesh and RVE size dependence that commonly plagues microscale damage calculations. The SCA method is illustrated with two cases: a carbon fiber reinforced polymer (CFRP) structure with the concurrent multiscale model and an application to fatigue prediction for additively manufactured metals. For the CFRP problem, a speed up estimated to be about

Modeling and Prediction of Soil Water Vapor Sorption Isotherms

DEFF Research Database (Denmark)

Arthur, Emmanuel; Tuller, Markus; Moldrup, Per

2015-01-01

Soil water vapor sorption isotherms describe the relationship between water activity (aw) and moisture content along adsorption and desorption paths. The isotherms are important for modeling numerous soil processes and are also used to estimate several soil (specific surface area, clay content.......93) for a wide range of soils; and (ii) develop and test regression models for estimating the isotherms from clay content. Preliminary results show reasonable fits of the majority of the investigated empirical and theoretical models to the measured data although some models were not capable to fit both sorption...... directions accurately. Evaluation of the developed prediction equations showed good estimation of the sorption/desorption isotherms for tested soils....

Multiphase flows of N immiscible incompressible fluids: A reduction-consistent and thermodynamically-consistent formulation and associated algorithm

Science.gov (United States)

Dong, S.

2018-05-01

We present a reduction-consistent and thermodynamically consistent formulation and an associated numerical algorithm for simulating the dynamics of an isothermal mixture consisting of N (N ⩾ 2) immiscible incompressible fluids with different physical properties (densities, viscosities, and pair-wise surface tensions). By reduction consistency we refer to the property that if only a set of M (1 ⩽ M ⩽ N - 1) fluids are present in the system then the N-phase governing equations and boundary conditions will exactly reduce to those for the corresponding M-phase system. By thermodynamic consistency we refer to the property that the formulation honors the thermodynamic principles. Our N-phase formulation is developed based on a more general method that allows for the systematic construction of reduction-consistent formulations, and the method suggests the existence of many possible forms of reduction-consistent and thermodynamically consistent N-phase formulations. Extensive numerical experiments have been presented for flow problems involving multiple fluid components and large density ratios and large viscosity ratios, and the simulation results are compared with the physical theories or the available physical solutions. The comparisons demonstrate that our method produces physically accurate results for this class of problems.

Consistency of self-reported alcohol consumption on randomized and sequential alcohol purchase tasks

Directory of Open Access Journals (Sweden)

Michael eAmlung

2012-07-01

Full Text Available Behavioral economic demand for addictive substances is commonly assessed via purchase tasks that measure estimated drug consumption at a range of prices. Purchase tasks typically use escalating prices in sequential order, which may influence performance by providing explicit price reference points. This study investigated the consistency of value preferences on two alcohol purchase tasks (APTs that used either a randomized or sequential price order (price range: free to $30 per drink in a sample of ninety-one young adult monthly drinkers. Randomization of prices significantly reduced relative response consistency (p < .01, although absolute consistency was high for both versions (>95%. Self-reported alcohol consumption across prices and indices of demand were highly similar across versions, although a few notable exceptions were found. These results suggest generally high consistency and overlapping performance between randomized and sequential price assessment. Implications for the behavioral economics literature and priorities for future research are discussed.

A Line Search Multilevel Truncated Newton Algorithm for Computing the Optical Flow

Directory of Open Access Journals (Sweden)

Lluís Garrido

2015-06-01

Full Text Available We describe the implementation details and give the experimental results of three optimization algorithms for dense optical flow computation. In particular, using a line search strategy, we evaluate the performance of the unilevel truncated Newton method (LSTN, a multiresolution truncated Newton (MR/LSTN and a full multigrid truncated Newton (FMG/LSTN. We use three image sequences and four models of optical flow for performance evaluation. The FMG/LSTN algorithm is shown to lead to better optical flow estimation with less computational work than both the LSTN and MR/LSTN algorithms.

Isothermal calorimeter for reactor radiation dosimetry

Energy Technology Data Exchange (ETDEWEB)

Radak, B; Markovic, V [Institute of Nuclear Sciences Boris Kidric, Odeljenje za radijacionu hemiju, Vinca, Beograd (Serbia and Montenegro)

1961-12-15

An isothermal calorimeter with thermistors for measuring absorbed dose rates from 10{sup 4}-5-6.10{sup 5} rad/h in reactor experimental holes has been designed. A kinetics method for determining the equilibrium temperature difference has been developed, and its application in isothermal calorimetry proved. The expected accuracy in measurements within {+-} 2-5% has been proved by measurements carried out in the reactor. Some data obtained by measurements in the reactor RA are presented (author)

Phase field modeling of dendritic coarsening during isothermal

Directory of Open Access Journals (Sweden)

Zhang Yutuo

2011-08-01

Full Text Available Dendritic coarsening in Al-2mol%Si alloy during isothermal solidification at 880K was investigated by phase field modeling. Three coarsening mechanisms operate in the alloy: (a melting of small dendrite arms; (b coalescence of dendrites near the tips leading to the entrapment of liquid droplets; (c smoothing of dendrites. Dendrite melting is found to be dominant in the stage of dendritic growth, whereas coalescence of dendrites and smoothing of dendrites are dominant during isothermal holding. The simulated results provide a better understanding of dendrite coarsening during isothermal solidification.

Effects of frequency mismatch on a self-consistent arbitrary amplitude cyclotron resonance laser accelerator

International Nuclear Information System (INIS)

Pakter, R.; Schneider, R.S.; Rizzato, F.B.

1993-01-01

The cyclotron-resonance laser accelerator (CRLA), where a coherent electromagnetic wave may transfer a large amount of energy to a beam of electrons gravitating in a guide magnetic field is studied. This large amount of transferred energy takes place due to the autoresonance mechanism where, under some ideal conditions, an initial wave-particle synchronism is self-sustained throughout the accelerating period. An improved analysis of the mentioned self-consistent wave-particle interaction, taking into account a possible frequency mismatch between wave and particles. It is also shown how the frequency mismatch can compensate the dispersion effects. (L.C.J.A.)

Fully self-consistent multiparticle-multi-hole configuration mixing method - Applications to a few light nuclei

International Nuclear Information System (INIS)

Robin, Caroline

2014-01-01

This thesis project takes part in the development of the multiparticle-multi-hole configuration mixing method aiming to describe the structure of atomic nuclei. Based on a double variational principle, this approach allows to determine the expansion coefficients of the wave function and the single-particle states at the same time. In this work we apply for the first time the fully self-consistent formalism of the mp-mh method to the description of a few p- and sd-shell nuclei, using the D1S Gogny interaction. A first study of the 12 C nucleus is performed in order to test the doubly iterative convergence procedure when different types of truncation criteria are applied to select the many-body configurations included in the wave-function. A detailed analysis of the effect caused by the orbital optimization is conducted. In particular, its impact on the one-body density and on the fragmentation of the ground state wave function is analyzed. A systematic study of sd-shell nuclei is then performed. A careful analysis of the correlation content of the ground state is first conducted and observables quantities such as binding and separation energies, as well as charge radii are calculated and compared to experimental data. Satisfactory results are found. Spectroscopic properties are also studied. Excitation energies of low-lying states are found in very good agreement with experiment, and the study of magnetic dipole features are also satisfactory. Calculation of electric quadrupole properties, and in particular transition probabilities B(E2), however reveal a clear lack of collectivity of the wave function, due to the reduced valence space used to select the many-body configurations. Although the renormalization of orbitals leads to an important fragmentation of the ground state wave function, only little effect is observed on B(E2) probabilities. A tentative explanation is given. Finally, the structure description of nuclei provided by the multiparticle

Low-mode truncation methods in the sine-Gordon equation

International Nuclear Information System (INIS)

Xiong Chuyu.

1991-01-01

In this dissertation, the author studies the chaotic and coherent motions (i.e., low-dimensional chaotic attractor) in some near integrable partial differential equations, particularly the sine-Gordon equation and the nonlinear Schroedinger equation. In order to study the motions, he uses low mode truncation methods to reduce these partial differential equations to some truncated models (low-dimensional ordinary differential equations). By applying many methods available to low-dimensional ordinary differential equations, he can understand the low-dimensional chaotic attractor of PDE's much better. However, there are two important questions one needs to answer: (1) How many modes is good enough for the low mode truncated models to capture the dynamics uniformly? (2) Is the chaotic attractor in a low mode truncated model close to the chaotic attractor in the original PDE? And how close is? He has developed two groups of powerful methods to help to answer these two questions. They are the computation methods of continuation and local bifurcation, and local Lyapunov exponents and Lyapunov exponents. Using these methods, he concludes that the 2N-nls ODE is a good model for the sine-Gordon equation and the nonlinear Schroedinger equation provided one chooses a 'good' basis and uses 'enough' modes (where 'enough' depends on the parameters of the system but is small for the parameter studied here). Therefore, one can use 2N-nls ODE to study the chaos of PDE's in more depth

Lethal mutants and truncated selection together solve a paradox of the origin of life.

Directory of Open Access Journals (Sweden)

David B Saakian

Full Text Available BACKGROUND: Many attempts have been made to describe the origin of life, one of which is Eigen's cycle of autocatalytic reactions [Eigen M (1971 Naturwissenschaften 58, 465-523], in which primordial life molecules are replicated with limited accuracy through autocatalytic reactions. For successful evolution, the information carrier (either RNA or DNA or their precursor must be transmitted to the next generation with a minimal number of misprints. In Eigen's theory, the maximum chain length that could be maintained is restricted to 100-1000 nucleotides, while for the most primitive genome the length is around 7000-20,000. This is the famous error catastrophe paradox. How to solve this puzzle is an interesting and important problem in the theory of the origin of life. METHODOLOGY/PRINCIPAL FINDINGS: We use methods of statistical physics to solve this paradox by carefully analyzing the implications of neutral and lethal mutants, and truncated selection (i.e., when fitness is zero after a certain Hamming distance from the master sequence for the critical chain length. While neutral mutants play an important role in evolution, they do not provide a solution to the paradox. We have found that lethal mutants and truncated selection together can solve the error catastrophe paradox. There is a principal difference between prebiotic molecule self-replication and proto-cell self-replication stages in the origin of life. CONCLUSIONS/SIGNIFICANCE: We have applied methods of statistical physics to make an important breakthrough in the molecular theory of the origin of life. Our results will inspire further studies on the molecular theory of the origin of life and biological evolution.

Efficient 3D/1D self-consistent integral-equation analysis of ICRH antennae

International Nuclear Information System (INIS)

Maggiora, R.; Vecchi, G.; Lancellotti, V.; Kyrytsya, V.

2004-01-01

This work presents a comprehensive account of the theory and implementation of a method for the self-consistent numerical analysis of plasma-facing ion-cyclotron resonance heating (ICRH) antenna arrays. The method is based on the integral-equation formulation of the boundary-value problem, solved via a weighted-residual scheme. The antenna geometry (including Faraday shield bars and a recess box) is fairly general and three-dimensional (3D), and the plasma is in the one-dimensional (1D) 'slab' approximation; finite-Larmor radius effects, as well as plasma density and temperature gradients, are considered. Feeding via the voltages in the access coaxial lines is self consistently accounted throughout and the impedance or scattering matrix of the antenna array obtained therefrom. The problem is formulated in both the dual space (physical) and spectral (wavenumber) domains, which allows the extraction and simple handling of the terms that slow the convergence in the spectral domain usually employed. This paper includes validation tests of the developed code against measured data, both in vacuo and in the presence of plasma. An example of application to a complex geometry is also given. (author)

Smaller self-inflating bags produce greater guideline consistent ventilation in simulated cardiopulmonary resuscitation.

Science.gov (United States)

Nehme, Ziad; Boyle, Malcolm J

2009-02-20

Suboptimal bag ventilation in cardiopulmonary resuscitation (CPR) has demonstrated detrimental physiological outcomes for cardiac arrest patients. In light of recent guideline changes for resuscitation, there is a need to identify the efficacy of bag ventilation by prehospital care providers. The objective of this study was to evaluate bag ventilation in relation to operator ability to achieve guideline consistent ventilation rate, tidal volume and minute volume when using two different capacity self-inflating bags in an undergraduate paramedic cohort. An experimental study using a mechanical lung model and a simulated adult cardiac arrest to assess the ventilation ability of third year Monash University undergraduate paramedic students. Participants were instructed to ventilate using 1600 ml and 1000 ml bags for a length of two minutes at the correct rate and tidal volume for a patient undergoing CPR with an advanced airway. Ventilation rate and tidal volume were recorded using an analogue scale with mean values calculated. Ethics approval was granted. Suboptimal ventilation with the use of conventional 1600 ml bag was common, with 77% and 97% of participants unable to achieve guideline consistent ventilation rates and tidal volumes respectively. Reduced levels of suboptimal ventilation arouse from the use of the smaller bag with a 27% reduction in suboptimal tidal volumes (p = 0.015) and 23% reduction in suboptimal minute volumes (p = 0.045). Smaller self-inflating bags reduce the incidence of suboptimal tidal volumes and minute volumes and produce greater guideline consistent results for cardiac arrest patients.

Alfven-wave particle interaction in finite-dimensional self-consistent field model

International Nuclear Information System (INIS)

Padhye, N.; Horton, W.

1998-01-01

A low-dimensional Hamiltonian model is derived for the acceleration of ions in finite amplitude Alfven waves in a finite pressure plasma sheet. The reduced low-dimensional wave-particle Hamiltonian is useful for describing the reaction of the accelerated ions on the wave amplitudes and phases through the self-consistent fields within the envelope approximation. As an example, the authors show for a single Alfven wave in the central plasma sheet of the Earth's geotail, modeled by the linear pinch geometry called the Harris sheet, the time variation of the wave amplitude during the acceleration of fast protons

Self-consistent analysis of radial electric field and fast ion losses in CHS Torsatron/Heliotron

International Nuclear Information System (INIS)

Sanuki, H.; Itoh, K.; Itoh, S.

1992-09-01

A self-consistent analysis is developed to determine the radial electric field and loss cone boundary in Torsatron/Heliotron plasmas under the influence of non-classical ion losses such as the loss cone loss ans charge exchange loss of fast ions with neutrals. Analysis is applied to the NBI heated plasmas in the Compact Helical System (CHS) device. Comparison is made between theoretical results and experimental observations. The increased ion particle losses caused by the orbit loss and charge exchange loss with neutrals make the radial electric field more negative than the value of purely neoclassical calculation. The partition of the injection energy among the shine through, direct orbit loss, change exchange loss and bulk heating is evaluated by using the self-consistent electric field profile. On-going experiments in the CHS device are briefly introduced. (author)

Self-consistent expansion for the molecular beam epitaxy equation.

Science.gov (United States)

Katzav, Eytan

2002-03-01

Motivated by a controversy over the correct results derived from the dynamic renormalization group (DRG) analysis of the nonlinear molecular beam epitaxy (MBE) equation, a self-consistent expansion for the nonlinear MBE theory is considered. The scaling exponents are obtained for spatially correlated noise of the general form D(r-r('),t-t('))=2D(0)[r-->-r(')](2rho-d)delta(t-t(')). I find a lower critical dimension d(c)(rho)=4+2rho, above which the linear MBE solution appears. Below the lower critical dimension a rho-dependent strong-coupling solution is found. These results help to resolve the controversy over the correct exponents that describe nonlinear MBE, using a reliable method that proved itself in the past by giving reasonable results for the strong-coupling regime of the Kardar-Parisi-Zhang system (for d>1), where DRG failed to do so.

Simulations of tokamak disruptions including self-consistent temperature evolution

International Nuclear Information System (INIS)

Bondeson, A.

1986-01-01

Three-dimensional simulations of tokamaks have been carried out, including self-consistent temperature evolution with a highly anisotropic thermal conductivity. The simulations extend over the transport time-scale and address the question of how disruptive current profiles arise at low-q or high-density operation. Sharply defined disruptive events are triggered by the m/n=2/1 resistive tearing mode, which is mainly affected by local current gradients near the q=2 surface. If the global current gradient between q=2 and q=1 is sufficiently steep, the m=2 mode starts a shock which accelerates towards the q=1 surface, leaving stochastic fields, a flattened temperature profile and turbulent plasma behind it. For slightly weaker global current gradients, a shock may form, but it will dissipate before reaching q=1 and may lead to repetitive minidisruptions which flatten the temperature profile in a region inside the q=2 surface. (author)

N-terminally truncated POM121C inhibits HIV-1 replication.

Directory of Open Access Journals (Sweden)

Hideki Saito

Full Text Available Recent studies have identified host cell factors that regulate early stages of HIV-1 infection including viral cDNA synthesis and orientation of the HIV-1 capsid (CA core toward the nuclear envelope, but it remains unclear how viral DNA is imported through the nuclear pore and guided to the host chromosomal DNA. Here, we demonstrate that N-terminally truncated POM121C, a component of the nuclear pore complex, blocks HIV-1 infection. This truncated protein is predominantly localized in the cytoplasm, does not bind to CA, does not affect viral cDNA synthesis, reduces the formation of 2-LTR and diminished the amount of integrated proviral DNA. Studies with an HIV-1-murine leukemia virus (MLV chimeric virus carrying the MLV-derived Gag revealed that Gag is a determinant of this inhibition. Intriguingly, mutational studies have revealed that the blockade by N-terminally-truncated POM121C is closely linked to its binding to importin-β/karyopherin subunit beta 1 (KPNB1. These results indicate that N-terminally-truncated POM121C inhibits HIV-1 infection after completion of reverse transcription and before integration, and suggest an important role for KPNB1 in HIV-1 replication.

Application of a molecular beacon based real-time isothermal amplification (MBRTIA) technology for simultaneous detection of Bacillus cereus and Staphylococcus aureus.

Science.gov (United States)

Mandappa, I M; Joglekar, Prasanna; Manonmani, H K

2015-07-01

A multiplex real-time isothermal amplification assay was developed using molecular beacons for the detection of Bacillus cereus and Staphylococcus aureus by targeting four important virulence genes. A correlation between targeting highly accessible DNA sequences and isothermal amplification based molecular beacon efficiency and sensitivity was demonstrated using phi(Φ)29 DNA polymerase at a constant isothermal temperature of 30 °C. It was very selective and consistently detected down to 10(1) copies of DNA. The specificity and sensitivity of this assay, when tested with pure culture were high, surpassing those of currently used PCR assays for the detection of these organisms. The molecular beacon based real-time isothermal amplification (MBRTIA) assay could be carried out entirely in 96 well plates or well strips, enabling a rapid and high-throughput detection of food borne pathogens.

Using Trait-State Models to Evaluate the Longitudinal Consistency of Global Self-Esteem From Adolescence to Adulthood

OpenAIRE

Donnellan, M. Brent; Kenny, David A.; Trzesniewski, Kali H.; Lucas, Richard E.; Conger, Rand D.

2012-01-01

The present research used a latent variable trait-state model to evaluate the longitudinal consistency of self-esteem during the transition from adolescence to adulthood. Analyses were based on ten administrations of the Rosenberg Self-Esteem scale (Rosenberg, 1965) spanning the ages of approximately 13 to 32 for a sample of 451 participants. Results indicated that a completely stable trait factor and an autoregressive trait factor accounted for the majority of the variance in latent self-est...

Estimation of Panel Data Regression Models with Two-Sided Censoring or Truncation

DEFF Research Database (Denmark)

Alan, Sule; Honore, Bo E.; Hu, Luojia

2014-01-01

This paper constructs estimators for panel data regression models with individual speci…fic heterogeneity and two–sided censoring and truncation. Following Powell (1986) the estimation strategy is based on moment conditions constructed from re–censored or re–truncated residuals. While these moment...

Self-consistent quasi-particle RPA for the description of superfluid Fermi systems

CERN Document Server

Rahbi, A; Chanfray, G; Schuck, P

2002-01-01

Self-Consistent Quasi-Particle RPA (SCQRPA) is for the first time applied to a more level pairing case. Various filling situation and values for the coupling constant are considered. Very encouraging results in comparison with the exact solution of the model are obtaining. The nature of the low lying mode in SCQRPA is identified. The strong reduction of the number fluctuation in SCQRPA vs BCS is pointed out. The transition from superfluidity to the normal fluid case is carefully investigated.

A generalized right truncated bivariate Poisson regression model with applications to health data.

Science.gov (United States)

Islam, M Ataharul; Chowdhury, Rafiqul I

2017-01-01

A generalized right truncated bivariate Poisson regression model is proposed in this paper. Estimation and tests for goodness of fit and over or under dispersion are illustrated for both untruncated and right truncated bivariate Poisson regression models using marginal-conditional approach. Estimation and test procedures are illustrated for bivariate Poisson regression models with applications to Health and Retirement Study data on number of health conditions and the number of health care services utilized. The proposed test statistics are easy to compute and it is evident from the results that the models fit the data very well. A comparison between the right truncated and untruncated bivariate Poisson regression models using the test for nonnested models clearly shows that the truncated model performs significantly better than the untruncated model.

Self-consistent approach to x-ray reflection from rough surfaces

International Nuclear Information System (INIS)

Feranchuk, I. D.; Feranchuk, S. I.; Ulyanenkov, A. P.

2007-01-01

A self-consistent analytical approach for specular x-ray reflection from interfaces with transition layers [I. D. Feranchuk et al., Phys. Rev. B 67, 235417 (2003)] based on the distorted-wave Born approximation (DWBA) is used for the description of coherent and incoherent x-ray scattering from rough surfaces and interfaces. This approach takes into account the transformation of the modeling transition layer profile at the interface, which is caused by roughness correlations. The reflection coefficients for each DWBA order are directly calculated without phenomenological assumptions on their exponential decay at large scattering angles. Various regions of scattering angles are discussed, which show qualitatively different dependence of the reflection coefficient on the scattering angle. The experimental data are analyzed using the method developed

Self-consistence equations for extended Feynman rules in quantum chromodynamics

International Nuclear Information System (INIS)

Wielenberg, A.

2005-01-01

In this thesis improved solutions for Green's functions are obtained. First the for this thesis essential techniques and concepts of QCD as euclidean field theory are presented. After a discussion of the foundations of the extended approach for the Feynman rules of QCD with a systematic approach for the 4-gluon vertex a modified renormalization scheme for the extended approach is developed. Thereafter the resummation of the Dyson-Schwinger equations (DSE) by the appropriately modified Bethe-Salpeter equation is discussed. Then the leading divergences for the 1-loop graphs of the resummed DSE are determined. Thereafter the equation-of-motion condensate is defined as result of an operator-product expansion. Then the self-consistency equations for the extended approaches are defined and numerically solved. (HSI)

A self-consistent model for polycrystal deformation. Description and implementation

International Nuclear Information System (INIS)

Clausen, B.; Lorentzen, T.

1997-04-01

This report is a manual for the ANSI C implementation of an incremental elastic-plastic rate-insensitive self-consistent polycrystal deformation model based on (Hutchinson 1970). The model is furthermore described in the Ph.D. thesis by Clausen (Clausen 1997). The structure of the main program, sc m odel.c, and its subroutines are described with flow-charts. Likewise the pre-processor, sc i ni.c, is described with a flowchart. Default values of all the input parameters are given in the pre-processor, but the user is able to select from other pre-defined values or enter new values. A sample calculation is made and the results are presented as plots and examples of the output files are shown. (au) 4 tabs., 28 ills., 17 refs

Self-consistent embedding of density-matrix renormalization group wavefunctions in a density functional environment.

Science.gov (United States)

Dresselhaus, Thomas; Neugebauer, Johannes; Knecht, Stefan; Keller, Sebastian; Ma, Yingjin; Reiher, Markus

2015-01-28

We present the first implementation of a density matrix renormalization group algorithm embedded in an environment described by density functional theory. The frozen density embedding scheme is used with a freeze-and-thaw strategy for a self-consistent polarization of the orbital-optimized wavefunction and the environmental densities with respect to each other.

Bounded real and positive real balanced truncation using Σ-normalised coprime factors

NARCIS (Netherlands)

Trentelman, H.L.

2009-01-01

In this article, we will extend the method of balanced truncation using normalised right coprime factors of the system transfer matrix to balanced truncation with preservation of half line dissipativity. Special cases are preservation of positive realness and bounded realness. We consider a half

Adsorption isotherms and kinetics for dibenzothiophene on activated

Indian Academy of Sciences (India)

Adsorption isotherms were obtained and desulphurization kinetics were carried out on solutions of dibenzothiophene (DBT) and thiophene in a model fuel. The efficiencies of DBT and thiophene removal were reported. The adsorption isotherms fitted the Langmuir and Freundlich models. The highest adsorption capacity for ...

A novel homozygous truncating GNAT1 mutation implicated in retinal degeneration.

Science.gov (United States)

Carrigan, Matthew; Duignan, Emma; Humphries, Pete; Palfi, Arpad; Kenna, Paul F; Farrar, G Jane

2016-04-01

The GNAT1 gene encodes the α subunit of the rod transducin protein, a key element in the rod phototransduction cascade. Variants in GNAT1 have been implicated in stationary night-blindness in the past, but unlike other proteins in the same pathway, it has not previously been implicated in retinitis pigmentosa. A panel of 182 retinopathy-associated genes was sequenced to locate disease-causing mutations in patients with inherited retinopathies. Sequencing revealed a novel homozygous truncating mutation in the GNAT1 gene in a patient with significant pigmentary disturbance and constriction of visual fields, a presentation consistent with retinitis pigmentosa. This is the first report of a patient homozygous for a complete loss-of-function GNAT1 mutation. The clinical data from this patient provide definitive evidence of retinitis pigmentosa with late onset in addition to the lifelong night-blindness that would be expected from a lack of transducin function. These data suggest that some truncating GNAT1 variants can indeed cause a recessive, mild, late-onset retinal degeneration in human beings rather than just stationary night-blindness as reported previously, with notable similarities to the phenotype of the Gnat1 knockout mouse. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

Investigation of the thermo-mechanical behavior of neutron-irradiated Fe-Cr alloys by self-consistent plasticity theory

Energy Technology Data Exchange (ETDEWEB)

Xiao, Xiazi [State Key Laboratory for Turbulence and Complex System, Department of Mechanics and Engineering Science, College of Engineering, Peking University, Beijing 100871 (China); CAPT, HEDPS and IFSA Collaborative Innovation Center of MoE, BIC-ESAT, Peking University, Beijing 100871 (China); Terentyev, Dmitry [Structural Material Group, Institute of Nuclear Materials Science, SCK CEN, Mol (Belgium); Yu, Long [State Key Laboratory for Turbulence and Complex System, Department of Mechanics and Engineering Science, College of Engineering, Peking University, Beijing 100871 (China); Bakaev, A. [Structural Material Group, Institute of Nuclear Materials Science, SCK CEN, Mol (Belgium); Jin, Zhaohui [School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Duan, Huiling, E-mail: hlduan@pku.edu.cn [State Key Laboratory for Turbulence and Complex System, Department of Mechanics and Engineering Science, College of Engineering, Peking University, Beijing 100871 (China); CAPT, HEDPS and IFSA Collaborative Innovation Center of MoE, BIC-ESAT, Peking University, Beijing 100871 (China)

2016-08-15

The thermo-mechanical behavior of non-irradiated (at 223 K, 302 K and 573 K) and neutron irradiated (at 573 K) Fe-2.5Cr, Fe-5Cr and Fe-9Cr alloys is studied by a self-consistent plasticity theory, which consists of constitutive equations describing the contribution of radiation defects at grain level, and the elastic-viscoplastic self-consistent method to obtain polycrystalline behaviors. Attention is paid to two types of radiation-induced defects: interstitial dislocation loops and solute rich clusters, which are believed to be the main sources of hardening in Fe-Cr alloys at medium irradiation doses. Both the hardening mechanism and microstructural evolution are investigated by using available experimental data on microstructures, and implementing hardening rules derived from atomistic data. Good agreement with experimental data is achieved for both the yield stress and strain hardening of non-irradiated and irradiated Fe-Cr alloys by treating dislocation loops as strong thermally activated obstacles and solute rich clusters as weak shearable ones. - Highlights: • A self-consistent plasticity theory is proposed for irradiated Fe-Cr alloys. • Both the irradiation-induced hardening and plastic flow evolution are studied. • Dislocation loops and solute rich clusters are considered as the main defects. • Numerical results of the proposed model match with corresponding experimental data.

Reduction of variable-truncation artifacts from beam occlusion during in situ x-ray tomography

Science.gov (United States)

Borg, Leise; Jørgensen, Jakob S.; Frikel, Jürgen; Sporring, Jon

2017-12-01

Many in situ x-ray tomography studies require experimental rigs which may partially occlude the beam and cause parts of the projection data to be missing. In a study of fluid flow in porous chalk using a percolation cell with four metal bars drastic streak artifacts arise in the filtered backprojection (FBP) reconstruction at certain orientations. Projections with non-trivial variable truncation caused by the metal bars are the source of these variable-truncation artifacts. To understand the artifacts a mathematical model of variable-truncation data as a function of metal bar radius and distance to sample is derived and verified numerically and with experimental data. The model accurately describes the arising variable-truncation artifacts across simulated variations of the experimental setup. Three variable-truncation artifact-reduction methods are proposed, all aimed at addressing sinogram discontinuities that are shown to be the source of the streaks. The ‘reduction to limited angle’ (RLA) method simply keeps only non-truncated projections; the ‘detector-directed smoothing’ (DDS) method smooths the discontinuities; while the ‘reflexive boundary condition’ (RBC) method enforces a zero derivative at the discontinuities. Experimental results using both simulated and real data show that the proposed methods effectively reduce variable-truncation artifacts. The RBC method is found to provide the best artifact reduction and preservation of image features using both visual and quantitative assessment. The analysis and artifact-reduction methods are designed in context of FBP reconstruction motivated by computational efficiency practical for large, real synchrotron data. While a specific variable-truncation case is considered, the proposed methods can be applied to general data cut-offs arising in different in situ x-ray tomography experiments.

Calculation of self-consistent potentials for substitutionally disordered systems with application to the Ag/sub x/-Pd/sub 1-x/ alloy series

International Nuclear Information System (INIS)

Winter, H.; Stocks, G.M.

1983-01-01

Previous Korringa-Kohn-Rostoker coherent-potential-approximation electronic-structure calculations for substitutionally random alloys have been based on ad hoc potentials. The lack of procedures suitable to provide self-consistent, parameter-free potentials prevented computations for systems consisting of dissimilar atoms and is also the reason why quantities like, for example, cohesive energies or lattice constants, have not so far been evaluated for systems of similar constituents. We present in full detail a generally applicable scheme devised for calculating the self-consistent electronic structures of substitutionally disordered systems. Its feasibility is demonstrated by presenting the results obtained for the Ag/sub x/Pd/sub 1-x/ alloy series. They are compared with those of former non-self-consistent calculations which use Mattheiss prescription potentials and the α = 1 Slater exchange, whereas the von Barth--Hedin expression is employed in our work. The differences are perceptible and have to be understood as combined self-consistency and exchange-correlation effects. .ID BW2039 .PG 905 909

Neurodegeneration caused by expression of human truncated tau leads to progressive neurobehavioural impairment in transgenic rats.

Science.gov (United States)

Hrnkova, Miroslava; Zilka, Norbert; Minichova, Zuzana; Koson, Peter; Novak, Michal

2007-01-26

Human truncated tau protein is an active constituent of the neurofibrillary degeneration in sporadic Alzheimer's disease. We have shown that modified tau protein, when expressed as a transgene in rats, induced AD characteristic tau cascade consisting of tau hyperphosphorylation, formation of argyrophilic tangles and sarcosyl-insoluble tau complexes. These pathological changes led to the functional impairment characterized by a variety of neurobehavioural symptoms. In the present study we have focused on the behavioural alterations induced by transgenic expression of human truncated tau. Transgenic rats underwent a battery of behavioural tests involving cognitive- and sensorimotor-dependent tasks accompanied with neurological assessment at the age of 4.5, 6 and 9 months. Behavioural examination of these rats showed altered spatial navigation in Morris water maze resulting in less time spent in target quadrant (popen field was not influenced by transgene expression. However beam walking test revealed that transgenic rats developed progressive sensorimotor disturbances related to the age of tested animals. The disturbances were most pronounced at the age of 9 months (p<0.01). Neurological alterations indicating impaired reflex responses were other added features of behavioural phenotype of this novel transgenic rat. These results allow us to suggest that neurodegeneration, caused by the non-mutated human truncated tau derived from sporadic human AD, result in the neuronal dysfunction consequently leading to the progressive neurobehavioural impairment.

Amplitude reconstruction from complete photoproduction experiments and truncated partial-wave expansions

International Nuclear Information System (INIS)

Workman, R. L.; Tiator, L.; Wunderlich, Y.; Doring, M.; Haberzettl, H.

2017-01-01

Here, we compare the methods of amplitude reconstruction, for a complete experiment and a truncated partial-wave analysis, applied to the photoproduction of pseudoscalar mesons. The approach is pedagogical, showing in detail how the amplitude reconstruction (observables measured at a single energy and angle) is related to a truncated partial-wave analysis (observables measured at a single energy and a number of angles).

Pressure variation of the valence band width in Ge: A self-consistent GW study

DEFF Research Database (Denmark)

Modak, Paritosh; Svane, Axel; Christensen, Niels Egede

2009-01-01

. In the present work we report results of quasiparticle self-consistent GW  (QSGW) band calculations for diamond- as well as β-tin-type Ge under pressure. For both phases we find that the band width increases with pressure. For β-tin Ge this agrees with experiment and density-functional theory, but for diamond Ge...

Self-consistent beam halo studies ampersand halo diagnostic development in a continuous linear focusing channel

International Nuclear Information System (INIS)

Jameson, R.A.

1994-01-01

Beam halos are formed via self-consistent motion of the beam particles. Interactions of single particles with time-varying density distributions of other particles are a major source of halo. Aspects of these interactions are studied for an initially equilibrium distribution in a radial, linear, continuous focusing system. When there is a mismatch, it is shown that in the self-consistent system, there is a threshold in space-charge and mismatch, above which a halo is formed that extends to ∼1.5 times the initial maximum mismatch radius. Tools are sought for characterizing the halo dynamics. Testing the particles against the width of the mismatch driving resonance is useful for finding a conservative estimate of the threshold. The exit, entering and transition times, and the time evolution of the halo, are also explored using this technique. Extension to higher dimensions is briefly discussed

Electron beam charging of insulators: A self-consistent flight-drift model

International Nuclear Information System (INIS)

Touzin, M.; Goeuriot, D.; Guerret-Piecourt, C.; Juve, D.; Treheux, D.; Fitting, H.-J.

2006-01-01

Electron beam irradiation and the self-consistent charge transport in bulk insulating samples are described by means of a new flight-drift model and an iterative computer simulation. Ballistic secondary electron and hole transport is followed by electron and hole drifts, their possible recombination and/or trapping in shallow and deep traps. The trap capture cross sections are the Poole-Frenkel-type temperature and field dependent. As a main result the spatial distributions of currents j(x,t), charges ρ(x,t), the field F(x,t), and the potential slope V(x,t) are obtained in a self-consistent procedure as well as the time-dependent secondary electron emission rate σ(t) and the surface potential V 0 (t). For bulk insulating samples the time-dependent distributions approach the final stationary state with j(x,t)=const=0 and σ=1. Especially for low electron beam energies E 0 G of a vacuum grid in front of the target surface. For high beam energies E 0 =10, 20, and 30 keV high negative surface potentials V 0 =-4, -14, and -24 kV are obtained, respectively. Besides open nonconductive samples also positive ion-covered samples and targets with a conducting and grounded layer (metal or carbon) on the surface have been considered as used in environmental scanning electron microscopy and common SEM in order to prevent charging. Indeed, the potential distributions V(x) are considerably small in magnitude and do not affect the incident electron beam neither by retarding field effects in front of the surface nor within the bulk insulating sample. Thus the spatial scattering and excitation distributions are almost not affected

Self-consistent nonlinear transmission line model of standing wave effects in a capacitive discharge

International Nuclear Information System (INIS)

Chabert, P.; Raimbault, J.L.; Rax, J.M.; Lieberman, M.A.

2004-01-01

It has been shown previously [Lieberman et al., Plasma Sources Sci. Technol. 11, 283 (2002)], using a non-self-consistent model based on solutions of Maxwell's equations, that several electromagnetic effects may compromise capacitive discharge uniformity. Among these, the standing wave effect dominates at low and moderate electron densities when the driving frequency is significantly greater than the usual 13.56 MHz. In the present work, two different global discharge models have been coupled to a transmission line model and used to obtain the self-consistent characteristics of the standing wave effect. An analytical solution for the wavelength λ was derived for the lossless case and compared to the numerical results. For typical plasma etching conditions (pressure 10-100 mTorr), a good approximation of the wavelength is λ/λ 0 ≅40 V 0 1/10 l -1/2 f -2/5 , where λ 0 is the wavelength in vacuum, V 0 is the rf voltage magnitude in volts at the discharge center, l is the electrode spacing in meters, and f the driving frequency in hertz

Towards a fully self-consistent inversion combining historical and paleomagnetic data for geomagnetic field reconstructions

Science.gov (United States)

Arneitz, P.; Leonhardt, R.; Fabian, K.; Egli, R.

2017-12-01

Historical and paleomagnetic data are the two main sources of information about the long-term geomagnetic field evolution. Historical observations extend to the late Middle Ages, and prior to the 19th century, they consisted mainly of pure declination measurements from navigation and orientation logs. Field reconstructions going back further in time rely solely on magnetization acquired by rocks, sediments, and archaeological artefacts. The combined dataset is characterized by a strongly inhomogeneous spatio-temporal distribution and highly variable data reliability and quality. Therefore, an adequate weighting of the data that correctly accounts for data density, type, and realistic error estimates represents the major challenge for an inversion approach. Until now, there has not been a fully self-consistent geomagnetic model that correctly recovers the variation of the geomagnetic dipole together with the higher-order spherical harmonics. Here we present a new geomagnetic field model for the last 4 kyrs based on historical, archeomagnetic and volcanic records. The iterative Bayesian inversion approach targets the implementation of reliable error treatment, which allows different record types to be combined in a fully self-consistent way. Modelling results will be presented along with a thorough analysis of model limitations, validity and sensitivity.

Self-consistency in the phonon space of the particle-phonon coupling model

Science.gov (United States)

Tselyaev, V.; Lyutorovich, N.; Speth, J.; Reinhard, P.-G.

2018-04-01

In the paper the nonlinear generalization of the time blocking approximation (TBA) is presented. The TBA is one of the versions of the extended random-phase approximation (RPA) developed within the Green-function method and the particle-phonon coupling model. In the generalized version of the TBA the self-consistency principle is extended onto the phonon space of the model. The numerical examples show that this nonlinear version of the TBA leads to the convergence of results with respect to enlarging the phonon space of the model.

Modified Truncated Multiplicity Analysis to Improve Verification of Uranium Fuel Cycle Materials

International Nuclear Information System (INIS)

LaFleur, A.; Miller, K.; Swinhoe, M.; Belian, A.; Croft, S.

2015-01-01

Accurate verification of 235U enrichment and mass in UF6 storage cylinders and the UO2F2 holdup contained in the process equipment is needed to improve international safeguards and nuclear material accountancy at uranium enrichment plants. Small UF6 cylinders (1.5'' and 5'' diameter) are used to store the full range of enrichments from depleted to highly-enriched UF6. For independent verification of these materials, it is essential that the 235U mass and enrichment measurements do not rely on facility operator declarations. Furthermore, in order to be deployed by IAEA inspectors to detect undeclared activities (e.g., during complementary access), it is also imperative that the measurement technique is quick, portable, and sensitive to a broad range of 235U masses. Truncated multiplicity analysis is a technique that reduces the variance in the measured count rates by only considering moments 1, 2, and 3 of the multiplicity distribution. This is especially important for reducing the uncertainty in the measured doubles and triples rates in environments with a high cosmic ray background relative to the uranium signal strength. However, we believe that the existing truncated multiplicity analysis throws away too much useful data by truncating the distribution after the third moment. This paper describes a modified truncated multiplicity analysis method that determines the optimal moment to truncate the multiplicity distribution based on the measured data. Experimental measurements of small UF6 cylinders and UO2F2 working reference materials were performed at Los Alamos National Laboratory (LANL). The data were analyzed using traditional and modified truncated multiplicity analysis to determine the optimal moment to truncate the multiplicity distribution to minimize the uncertainty in the measured count rates. The results from this analysis directly support nuclear safeguards at enrichment plants and provide a more accurate verification method for UF6

Self-Consistent Dynamical Model of the Broad Line Region

Energy Technology Data Exchange (ETDEWEB)

Czerny, Bozena [Center for Theoretical Physics, Polish Academy of Sciences, Warsaw (Poland); Li, Yan-Rong [Key Laboratory for Particle Astrophysics, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing (China); Sredzinska, Justyna; Hryniewicz, Krzysztof [Copernicus Astronomical Center, Polish Academy of Sciences, Warsaw (Poland); Panda, Swayam [Center for Theoretical Physics, Polish Academy of Sciences, Warsaw (Poland); Copernicus Astronomical Center, Polish Academy of Sciences, Warsaw (Poland); Wildy, Conor [Center for Theoretical Physics, Polish Academy of Sciences, Warsaw (Poland); Karas, Vladimir, E-mail: bcz@cft.edu.pl [Astronomical Institute, Czech Academy of Sciences, Prague (Czech Republic)

2017-06-22

We develop a self-consistent description of the Broad Line Region based on the concept of a failed wind powered by radiation pressure acting on a dusty accretion disk atmosphere in Keplerian motion. The material raised high above the disk is illuminated, dust evaporates, and the matter falls back toward the disk. This material is the source of emission lines. The model predicts the inner and outer radius of the region, the cloud dynamics under the dust radiation pressure and, subsequently, the gravitational field of the central black hole, which results in asymmetry between the rise and fall. Knowledge of the dynamics allows us to predict the shapes of the emission lines as functions of the basic parameters of an active nucleus: black hole mass, accretion rate, black hole spin (or accretion efficiency) and the viewing angle with respect to the symmetry axis. Here we show preliminary results based on analytical approximations to the cloud motion.

First principles molecular dynamics without self-consistent field optimization

International Nuclear Information System (INIS)

Souvatzis, Petros; Niklasson, Anders M. N.

2014-01-01

We present a first principles molecular dynamics approach that is based on time-reversible extended Lagrangian Born-Oppenheimer molecular dynamics [A. M. N. Niklasson, Phys. Rev. Lett. 100, 123004 (2008)] in the limit of vanishing self-consistent field optimization. The optimization-free dynamics keeps the computational cost to a minimum and typically provides molecular trajectories that closely follow the exact Born-Oppenheimer potential energy surface. Only one single diagonalization and Hamiltonian (or Fockian) construction are required in each integration time step. The proposed dynamics is derived for a general free-energy potential surface valid at finite electronic temperatures within hybrid density functional theory. Even in the event of irregular functional behavior that may cause a dynamical instability, the optimization-free limit represents a natural starting guess for force calculations that may require a more elaborate iterative electronic ground state optimization. Our optimization-free dynamics thus represents a flexible theoretical framework for a broad and general class of ab initio molecular dynamics simulations

Self-consistent Langmuir waves in resonantly driven thermal plasmas

Science.gov (United States)

Lindberg, R. R.; Charman, A. E.; Wurtele, J. S.

2007-12-01

The longitudinal dynamics of a resonantly driven Langmuir wave are analyzed in the limit that the growth of the electrostatic wave is slow compared to the bounce frequency. Using simple physical arguments, the nonlinear distribution function is shown to be nearly invariant in the canonical particle action, provided both a spatially uniform term and higher-order spatial harmonics are included along with the fundamental in the longitudinal electric field. Requirements of self-consistency with the electrostatic potential yield the basic properties of the nonlinear distribution function, including a frequency shift that agrees closely with driven, electrostatic particle simulations over a range of temperatures. This extends earlier work on nonlinear Langmuir waves by Morales and O'Neil [G. J. Morales and T. M. O'Neil, Phys. Rev. Lett. 28, 417 (1972)] and Dewar [R. L. Dewar, Phys. Plasmas 15, 712 (1972)], and could form the basis of a reduced kinetic treatment of plasma dynamics for accelerator applications or Raman backscatter.

Self-consistent Langmuir waves in resonantly driven thermal plasmas

International Nuclear Information System (INIS)

Lindberg, R. R.; Charman, A. E.; Wurtele, J. S.

2007-01-01

The longitudinal dynamics of a resonantly driven Langmuir wave are analyzed in the limit that the growth of the electrostatic wave is slow compared to the bounce frequency. Using simple physical arguments, the nonlinear distribution function is shown to be nearly invariant in the canonical particle action, provided both a spatially uniform term and higher-order spatial harmonics are included along with the fundamental in the longitudinal electric field. Requirements of self-consistency with the electrostatic potential yield the basic properties of the nonlinear distribution function, including a frequency shift that agrees closely with driven, electrostatic particle simulations over a range of temperatures. This extends earlier work on nonlinear Langmuir waves by Morales and O'Neil [G. J. Morales and T. M. O'Neil, Phys. Rev. Lett. 28, 417 (1972)] and Dewar [R. L. Dewar, Phys. Plasmas 15, 712 (1972)], and could form the basis of a reduced kinetic treatment of plasma dynamics for accelerator applications or Raman backscatter

Self-Consistent Dynamical Model of the Broad Line Region

Directory of Open Access Journals (Sweden)

Bozena Czerny

2017-06-01

Full Text Available We develop a self-consistent description of the Broad Line Region based on the concept of a failed wind powered by radiation pressure acting on a dusty accretion disk atmosphere in Keplerian motion. The material raised high above the disk is illuminated, dust evaporates, and the matter falls back toward the disk. This material is the source of emission lines. The model predicts the inner and outer radius of the region, the cloud dynamics under the dust radiation pressure and, subsequently, the gravitational field of the central black hole, which results in asymmetry between the rise and fall. Knowledge of the dynamics allows us to predict the shapes of the emission lines as functions of the basic parameters of an active nucleus: black hole mass, accretion rate, black hole spin (or accretion efficiency and the viewing angle with respect to the symmetry axis. Here we show preliminary results based on analytical approximations to the cloud motion.

Inversion of Solid Earth's Varying Shape 2: Using Self-Consistency to Infer Static Ocean Topography

Science.gov (United States)

Blewitt, G.; Clarke, P. J.

2002-12-01

We have developed a spectral approach to invert for the redistribution of mass on the Earth's surface given precise global geodetic measurements of the solid Earth's geometrical shape. We used the elastic load Love number formalism to characterize the redistributed mass as a spherical harmonic expansion, truncated at some degree and order n. [Clarke and Blewitt, this meeting]. Here we incorporate the additional physical constraint that the sea surface in hydrostatic equilibrium corresponds to an equipotential surface, to infer the non-steric component of static ocean topography. Our model rigorously accounts for self-gravitation of the ocean, continental surface mass, and the deformed solid Earth, such that the sea surface adopts a new equipotential surface consistent with ocean-land mass exchange, deformation of the geoid, deformation of the sea floor, and the geographical configuration of the oceans and continents. We develop a self-consistent spectral inversion method to solve for the distribution of continental surface mass that would generate geographic variations in relative mean sea level such that the total (ocean plus continental) mass distribution agrees with the original geodetic estimates to degree and order n. We apply this theory to study the contribution of seasonal inter-hemispheric (degree-1) mass transfer to seasonal variation in static ocean topography, using a published empirical seasonal model for degree-1 surface loading derived using GPS coordinate time series from the global IGS network [Blewitt et al., Science 294, 2,342-2,345, 2001]. The resulting predictions of seasonal variations of relative sea level strongly depend on location, with peak variations ranging from 3 mm to 19 mm. The largest peak variations are predicted in mid-August around Antarctica and the southern hemisphere in general; the lowest variations are predicted in the northern hemisphere. Corresponding maximum continental loading occurs in Canada and Siberia at the water

Mathematical modelling of non-isothermal venturi scrubbers

Energy Technology Data Exchange (ETDEWEB)

Rahimi, A. [Isfahan Univ., Isfahan (Iran, Islamic Republic of). Dept. of Chemical Engineering; Taheri, M.; Fathikakajahi, J. [Shiraz Univ., Shiraz (Iran, Islamic Republic of). Dept. of Chemical Engineering

2005-06-01

Venturi scrubbers collect gaseous pollutants and particulate matter from industrial exhaust. This air pollution control device is highly efficient, easy to maintain and has a low initial cost. However, the high pressure drop through the device results in a high running cost. The main mechanism for collecting particulates is the inertial impaction of the particles on the droplets, which occurs due to high velocity between the gas stream and droplets. Droplet acceleration and irreversible drag-force which results from this high relative velocity are responsible for the high pressure drop in this type of scrubber. While several attempts have been made to mathematically model particulate removal in Venturi scrubbers, most models do not consider simultaneous heat and mass transfer. This factor is important because most Venturi scrubbers operate under non-isothermal conditions where the inlet gas is humidified in order to cool it before entering the scrubber. For that reason, the authors developed a more realistic model to determine the effects of heat and mass transfer on the particulate removal efficiency of a non-isothermal Venturi type scrubber. The model considers the effect of droplet size distribution and liquid film flow on the walls. It consists of differential equations for energy, momentum and material exchange. Model results were compared with data from experimental studies and industrial facilities. It was concluded that the removal efficiency of the scrubber is influenced by the inlet humidity temperature of the inlet gas. 26 refs., 1 tab., 10 figs.

Smaller self-inflating bags produce greater guideline consistent ventilation in simulated cardiopulmonary resuscitation

Directory of Open Access Journals (Sweden)

Boyle Malcolm J

2009-02-01

Full Text Available Abstract Background Suboptimal bag ventilation in cardiopulmonary resuscitation (CPR has demonstrated detrimental physiological outcomes for cardiac arrest patients. In light of recent guideline changes for resuscitation, there is a need to identify the efficacy of bag ventilation by prehospital care providers. The objective of this study was to evaluate bag ventilation in relation to operator ability to achieve guideline consistent ventilation rate, tidal volume and minute volume when using two different capacity self-inflating bags in an undergraduate paramedic cohort. Methods An experimental study using a mechanical lung model and a simulated adult cardiac arrest to assess the ventilation ability of third year Monash University undergraduate paramedic students. Participants were instructed to ventilate using 1600 ml and 1000 ml bags for a length of two minutes at the correct rate and tidal volume for a patient undergoing CPR with an advanced airway. Ventilation rate and tidal volume were recorded using an analogue scale with mean values calculated. Ethics approval was granted. Results Suboptimal ventilation with the use of conventional 1600 ml bag was common, with 77% and 97% of participants unable to achieve guideline consistent ventilation rates and tidal volumes respectively. Reduced levels of suboptimal ventilation arouse from the use of the smaller bag with a 27% reduction in suboptimal tidal volumes (p = 0.015 and 23% reduction in suboptimal minute volumes (p = 0.045. Conclusion Smaller self-inflating bags reduce the incidence of suboptimal tidal volumes and minute volumes and produce greater guideline consistent results for cardiac arrest patients.

A Lynden-Bell integral estimator for the tail index of right-truncated ...

African Journals Online (AJOL)

By means of a Lynden-Bell integral with deterministic threshold, Worms and Worms [A Lynden-Bell integral estimator for extremes of randomly truncated data. Statist. Probab. Lett. 2016; 109: 106-117] recently introduced an asymptotically normal estimator of the tail index for randomly right-truncated Pareto-type data.

Truncated States Obtained by Iteration

International Nuclear Information System (INIS)

Cardoso, W. B.; Almeida, N. G. de

2008-01-01

We introduce the concept of truncated states obtained via iterative processes (TSI) and study its statistical features, making an analogy with dynamical systems theory (DST). As a specific example, we have studied TSI for the doubling and the logistic functions, which are standard functions in studying chaos. TSI for both the doubling and logistic functions exhibit certain similar patterns when their statistical features are compared from the point of view of DST

Isothermal and non-isothermal infiltration and deuterium transport: a case study in a soil column from a headwater catchment

Czech Academy of Sciences Publication Activity Database

Sobotková, M.; Sněhota, M.; Budínová, E.; Tesař, Miroslav

2017-01-01

Roč. 65, č. 3 (2017), s. 234-243 ISSN 0042-790X Grant - others:GA ČR(CZ) GA14-03691S Institutional support: RVO:67985874 Keywords : isothermal infiltration * non-isothermal infiltration * column leaching * breakthrough curve * deuterium * viscosity * capillary trapping * entrapped air * permeability Subject RIV: DA - Hydrology ; Limnology OBOR OECD: Environmental sciences (social aspects to be 5.7) Impact factor: 1.654, year: 2016

The Dynamics of Truncated Black Hole Accretion Disks. I. Viscous Hydrodynamic Case

Energy Technology Data Exchange (ETDEWEB)

Hogg, J. Drew; Reynolds, Christopher S. [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States)

2017-07-10

Truncated accretion disks are commonly invoked to explain the spectro-temporal variability in accreting black holes in both small systems, i.e., state transitions in galactic black hole binaries (GBHBs), and large systems, i.e., low-luminosity active galactic nuclei (LLAGNs). In the canonical truncated disk model of moderately low accretion rate systems, gas in the inner region of the accretion disk occupies a hot, radiatively inefficient phase, which leads to a geometrically thick disk, while the gas in the outer region occupies a cooler, radiatively efficient phase that resides in the standard geometrically thin disk. Observationally, there is strong empirical evidence to support this phenomenological model, but a detailed understanding of the dynamics of truncated disks is lacking. We present a well-resolved viscous, hydrodynamic simulation that uses an ad hoc cooling prescription to drive a thermal instability and, hence, produce the first sustained truncated accretion disk. With this simulation, we perform a study of the dynamics, angular momentum transport, and energetics of a truncated disk. We find that the time variability introduced by the quasi-periodic transition of gas from efficient cooling to inefficient cooling impacts the evolution of the simulated disk. A consequence of the thermal instability is that an outflow is launched from the hot/cold gas interface, which drives large, sub-Keplerian convective cells into the disk atmosphere. The convective cells introduce a viscous θ − ϕ stress that is less than the generic r − ϕ viscous stress component, but greatly influences the evolution of the disk. In the truncated disk, we find that the bulk of the accreted gas is in the hot phase.

Self-consistent approximation for muffin-tin models of random substitutional alloys with environmental disorder

International Nuclear Information System (INIS)

Kaplan, T.; Gray, L.J.

1984-01-01

The self-consistent approximation of Kaplan, Leath, Gray, and Diehl is applied to models for substitutional random alloys with muffin-tin potentials. The particular advantage of this approximation is that, in addition to including cluster scattering, the muffin-tin potentials in the alloy can depend on the occupation of the surrounding sites (i.e., environmental disorder is included)

Structure of disordered alloys - II: self-consistent CCPA calculations for III-V semiconducting alloys

International Nuclear Information System (INIS)

Mookerjee, A.; Chaudhry, V.

1980-09-01

Using the chemical pseudopotential approach of Anderson and Bullett we have generated from first principles pseudo-Hamiltonians for heteropolar alloys. The one-electron density of states has been generated for Gasub(x)Insub(1-x)As using a self-consistent cluster CPA introduced earlier by one of us. Off-diagonal disorder has also been incorporated. (author)

A Multistep Extending Truncation Method towards Model Construction of Infinite-State Markov Chains

Directory of Open Access Journals (Sweden)

Kemin Wang

2014-01-01

Full Text Available The model checking of Infinite-State Continuous Time Markov Chains will inevitably encounter the state explosion problem when constructing the CTMCs model; our method is to get a truncated model of the infinite one; to get a sufficient truncated model to meet the model checking of Continuous Stochastic Logic based system properties, we propose a multistep extending advanced truncation method towards model construction of CTMCs and implement it in the INFAMY model checker; the experiment results show that our method is effective.

Self-consistent RPA and the time-dependent density matrix approach

Energy Technology Data Exchange (ETDEWEB)

Schuck, P. [Institut de Physique Nucleaire, Orsay (France); CNRS et Universite Joseph Fourier, Laboratoire de Physique et Modelisation des Milieux Condenses, Grenoble (France); Tohyama, M. [Kyorin University School of Medicine, Mitaka, Tokyo (Japan)

2016-10-15

The time-dependent density matrix (TDDM) or BBGKY (Bogoliubov, Born, Green, Kirkwood, Yvon) approach is decoupled and closed at the three-body level in finding a natural representation of the latter in terms of a quadratic form of two-body correlation functions. In the small amplitude limit an extended RPA coupled to an also extended second RPA is obtained. Since including two-body correlations means that the ground state cannot be a Hartree-Fock state, naturally the corresponding RPA is upgraded to Self-Consistent RPA (SCRPA) which was introduced independently earlier and which is built on a correlated ground state. SCRPA conserves all the properties of standard RPA. Applications to the exactly solvable Lipkin and the 1D Hubbard models show good performances of SCRPA and TDDM. (orig.)

A self-consistent model for polycrystal deformation. Description and implementation

Energy Technology Data Exchange (ETDEWEB)

Clausen, B.; Lorentzen, T.

1997-04-01

This report is a manual for the ANSI C implementation of an incremental elastic-plastic rate-insensitive self-consistent polycrystal deformation model based on (Hutchinson 1970). The model is furthermore described in the Ph.D. thesis by Clausen (Clausen 1997). The structure of the main program, sc{sub m}odel.c, and its subroutines are described with flow-charts. Likewise the pre-processor, sc{sub i}ni.c, is described with a flowchart. Default values of all the input parameters are given in the pre-processor, but the user is able to select from other pre-defined values or enter new values. A sample calculation is made and the results are presented as plots and examples of the output files are shown. (au) 4 tabs., 28 ills., 17 refs.

A self-consistent turbulence generated scenario for L-H transition

International Nuclear Information System (INIS)

Zhang, Y.Z.; Mahajan, S.M.

1992-10-01

The turbulence-induced ion banana polarization current associated with steep ion temperature gradients is explored as a possible mechanism for generating poloidal momentum at the tokamak edge. In the light of a recently developed two-dimensional turbulence theory, one can obtain a simple closed expression relating this current (determined by turbulence levels) to the derivatives of the poloidal rotation speed. A self-consistent system, then, emerges, if we balance the turbulence-induced poloidal momentum with that dissipated by viscosity. Under suitable conditions this system may show a bifurcation controlled by a parameter dependent on temperature gradients. Both the bifurcation point, and the shear layer width are predicted for a prescribed flow in terms of a scale characterizing the nonlinearity of viscosity. The crucial relevance of the flow parity with the turbulence scenario is analyzed

A modified KdV equation with self-consistent sources in non-uniform media and soliton dynamics

International Nuclear Information System (INIS)

Zhang Dajun; Bi Jinbo; Hao Honghai

2006-01-01

Two non-isospectral modified KdV equations with self-consistent sources are derived, which correspond to the time-dependent spectral parameter λ satisfying λ t = λ and λ t = λ 3 , respectively. Gauge transformation between the first non-isospectral equation (corresponding to λ t = λ) and its isospectral counterpart is given, from which exact solutions and conservation laws for the non-isospectral one are easily listed. Besides, solutions to the two non-isospectral modified KdV equations with self-consistent sources are derived by means of the Hirota method and the Wronskian technique, respectively. Non-isospectral dynamics and source effects, including one-soliton characteristics in non-uniform media, two-solitons scattering and special behaviours related to sources (for example, the 'ghost' solitons in the degenerate two-soliton case), are investigated analytically

The Plumber’s Nightmare Phase in Diblock Copolymer/Homopolymer Blends. A Self-Consistent Field Theory Study.

KAUST Repository

Martinez-Veracoechea, Francisco J.

2009-11-24

Using self-consistent field theory, the Plumber\\'s Nightmare and the double diamond phases are predicted to be stable in a finite region of phase diagrams for blends of AB diblock copolymer (DBC) and A-component homopolymer. To the best of our knowledge, this is the first time that the P phase has been predicted to be stable using self-consistent field theory. The stabilization is achieved by tuning the composition or conformational asymmetry of the DBC chain, and the architecture or length of the homopolymer. The basic features of the phase diagrams are the same in all cases studied, suggesting a general type of behavior for these systems. Finally, it is noted that the homopolymer length should be a convenient variable to stabilize bicontinuous phases in experiments. © 2009 American Chemical Society.

Pulling it all together: the self-consistent distribution of neutral tori in Saturn's Magnetosphere based on all Cassini observations

Science.gov (United States)

Smith, H. T.; Richardson, J. D.

2017-12-01

Saturn's magnetosphere is unique in that the plumes from the small icy moon, Enceladus, serve at the primary source for heavy particles in Saturn's magnetosphere. The resulting co-orbiting neutral particles interact with ions, electrons, photons and other neutral particles to generate separate H2O, OH and O tori. Characterization of these toroidal distributions is essential for understanding Saturn magnetospheric sources, composition and dynamics. Unfortunately, limited direct observations of these features are available so modeling is required. A significant modeling challenge involves ensuring that either the plasma and neutral particle populations are not simply input conditions but can provide feedback to each population (i.e. are self-consistent). Jurac and Richardson (2005) executed such a self-consistent model however this research was performed prior to the return of Cassini data. In a similar fashion, we have coupled a 3-D neutral particle model (Smith et al. 2004, 2005, 2006, 2007, 2009, 2010) with a plasma transport model (Richardson 1998; Richardson & Jurac 2004) to develop a self-consistent model which is constrained by all available Cassini observations and current findings on Saturn's magnetosphere and the Enceladus plume source resulting in much more accurate neutral particle distributions. We present a new self-consistent model of the distribution of the Enceladus-generated neutral tori that is validated by all available observations. We also discuss the implications for source rate and variability.

Bootstrapping gravity: A consistent approach to energy-momentum self-coupling

International Nuclear Information System (INIS)

Butcher, Luke M.; Hobson, Michael; Lasenby, Anthony

2009-01-01

It is generally believed that coupling the graviton (a classical Fierz-Pauli massless spin-2 field) to its own energy-momentum tensor successfully recreates the dynamics of the Einstein field equations order by order; however the validity of this idea has recently been brought into doubt [T. Padmanabhan, Int. J. Mod. Phys. D 17, 367 (2008).]. Motivated by this, we present a graviton action for which energy-momentum self-coupling is indeed consistent with the Einstein field equations. The Hilbert energy-momentum tensor for this graviton is calculated explicitly and shown to supply the correct second-order term in the field equations; in contrast, the Fierz-Pauli action fails to supply the correct term. A formalism for perturbative expansions of metric-based gravitational theories is then developed, and these techniques employed to demonstrate that our graviton action is a starting point for a straightforward energy-momentum self-coupling procedure that, order by order, generates the Einstein-Hilbert action (up to a classically irrelevant surface term). The perturbative formalism is extended to include matter and a cosmological constant, and interactions between perturbations of a free matter field and the gravitational field are studied in a vacuum background. Finally, the effect of a nonvacuum background is examined, and the graviton is found to develop a nonvanishing 'mass-term' in the action.

Molecular dynamics simulations of lipid bilayers : major artifacts due to truncating electrostatic interactions

NARCIS (Netherlands)

Patra, M.; Karttunen, M.E.J.; Hyvönen, M.T.; Falck, E.; Lindqvist, P.; Vattulainen, I.

2003-01-01

We study the influence of truncating the electrostatic interactions in a fully hydrated pure dipalmitoylphosphatidylcholine (DPPC) bilayer through 20 ns molecular dynamics simulations. The computations in which the electrostatic interactions were truncated are compared to similar simulations using

Distinct Ezrin Truncations Differentiate Metastases in Sentinel Lymph Nodes from Unaffected Lymph Node Tissues, from Primary Breast Tumors, and from Healthy Glandular Breast Tissues

Directory of Open Access Journals (Sweden)

Claudia Röwer

2018-02-01

Full Text Available BACKGROUND: Lymph node metastasis status is a prognostic factor for further lymph node involvement and for patient survival in breast cancer patients. Frozen section analysis of lymph nodes is a reliable method for detection of macro-metastases. However, this method is far less effective in detecting micro-metastases, requesting improved diagnostic procedures. METHODS: We investigated expression and truncation of ezrin in (i sentinel lymph node metastases, (ii unaffected axillary lymph nodes, (iii primary breast tumors, and (iv healthy glandular breast tissues using 2D gel electrophoresis, SDS-PAGE, and mass spectrometry in addition to Western blotting. RESULTS: Full-length ezrin (E1; amino acids 1–586 is present in all four investigated tissues. Two truncated ezrin forms, one missing about the first hundred amino acids (E2a and the other lacking about 150 C-terminal amino acids (E2b were detectable in primary tumor tissues and in sentinel lymph node metastases but not in glandular tissues. Strikingly, an ezrin truncation (E3 which consists approximately of amino acids 238–586 was found strongly expressed in all sentinel lymph node metastases. Moreover, an N-terminal ezrin fragment (E4 that consists approximately of amino acids 1–273 was identified in sentinel lymph node metastases as well. CONCLUSIONS: We show for the first time the existence of tissue-dependent specific ezrin truncations. The distinguished strong Western blot staining of ezrin E3 in sentinel lymph node metastases underlines its capability to substantiate the occurrence of lymph node (micrometastases in breast cancer patients.

Multiconfigurational self-consistent field calculations of nuclear shieldings using London atomic orbitals

DEFF Research Database (Denmark)

Ruud, Kenneth; Helgaker, Trygve; Kobayashi, Rika

1994-01-01

to corresponding individual gauges for localized orbitals (IGLO) results. The London results show better basis set convergence than IGLO, especially for heavier atoms. It is shown that the choice of active space is crucial for determination of accurate nuclear shielding constants.......Nuclear shielding calculations are presented for multiconfigurational self-consistent field wave functions using London atomic orbitals (gauge invariant atomic orbitals). Calculations of nuclear shieldings for eight molecules (H2O, H2S, CH4, N2, CO, HF, F2, and SO2) are presented and compared...

Effective Field Theories and the Role of Consistency in Theory Choice

CERN Document Server

Wells, James D

2012-01-01

Promoting a theory with a finite number of terms into an effective field theory with an infinite number of terms worsens simplicity, predictability, falsifiability, and other attributes often favored in theory choice. However, the importance of these attributes pales in comparison with consistency, both observational and mathematical consistency, which propels the effective theory to be superior to its simpler truncated version of finite terms, whether that theory be renormalizable (e.g., Standard Model of particle physics) or nonrenormalizable (e.g., gravity). Some implications for the Large Hadron Collider and beyond are discussed, including comments on how directly acknowledging the preeminence of consistency can affect future theory work.

Ice formation in PEM fuel cells operated isothermally at sub-freezing temperatures

Energy Technology Data Exchange (ETDEWEB)

Mukundan, Rangachary [Los Alamos National Laboratory; Luhan, Roger W [Los Alamos National Laboratory; Davey, John R [Los Alamos National Laboratory; Spendelow, Jacob S [Los Alamos National Laboratory; Borup, Rodney L [Los Alamos National Laboratory; Hussey, Daniel S [NIST; Jacobson, David L [NIST; Arif, Muhammad [NIST

2009-01-01

The effect of MEA and GDL structure and composition on the performance of single-PEM fuel cells operated isothermally at subfreezing temperatures is presented. The cell performance and durability are not only dependent on the MEA/GDL materials used but also on their interfaces. When a cell is operated isothermally at sub-freezing temperatures in constant current mode, the water formation due to the current density initially hydrates the membrane/ionomer and then forms ice in the catalyst layer/GDL. An increase in high frequency resistance was also observed in certain MEAs where there is a possibility of ice formation between the catalyst layer and GDL leading to a loss in contact area. The total water/ice holding capacity for any MEA was lower at lower temperatures and higher current densities. The durability of MEAs subjected to multiple isothermal starts was better for LANL prepared MEAs as compared to commercial MEAs, and cloth GDLs when compared to paper GDLs. The ice formation was monitored using high-resolution neutron radiography and was found to be concentrated near the cathode catalyst layer. However, there was significant ice formation in the GDLs especially at the higher temperature ({approx} -10 C) and lower current density (0.02 A/cm{sup 2}) operations. These results are consistent with the longer-term durability observations that show more severe degradation at the lower temperatures.

On the viability of the truncated Israel–Stewart theory in cosmology

International Nuclear Information System (INIS)

Shogin, Dmitry; Amundsen, Per Amund; Hervik, Sigbjørn

2015-01-01

We apply the causal Israel–Stewart theory of irreversible thermodynamics to model the matter content of the Universe as a dissipative fluid with bulk and shear viscosity. Along with the full transport equations we consider their widely used truncated version. By implementing a dynamical systems approach to Bianchi type IV and V cosmological models with and without cosmological constant, we determine the future asymptotic states of such Universes and show that the truncated Israel–Stewart theory leads to solutions essentially different from the full theory. The solutions of the truncated theory may also manifest unphysical properties. Finally, we find that in the full theory shear viscosity can give a substantial rise to dissipative fluxes, driving the fluid extremely far from equilibrium, where the linear Israel–Stewart theory ceases to be valid. (paper)

Ultrasmall volume molecular isothermal amplification in microfluidic chip with advanced surface processing

International Nuclear Information System (INIS)

Huang Guoliang; Yang Xiaoyong; Ma Li; Yang Xu

2011-01-01

In this paper, we developed a metal micro-fluidic chip with advanced surface processing for ultra-small volume molecular isothermal amplification. This method takes advantages of the nucleic acid amplification with good stability and consistency, high sensitivity about 31 genomic DNA copies and bacteria specific gene identification. Based on the advanced surface processing, the bioreaction assays of nucleic acid amplification was dropped about 392nl in volume. A high numerical aperture confocal optical detection system was advanced to sensitively monitor the DNA amplification with low noise and high power collecting fluorescence near to the optical diffraction limit. A speedy nucleic acid isothermal amplification was performed in the ultra-small volume microfluidic chip, where the time at the inflexions of second derivative to DNA exponential amplified curves was brought forward and the sensitivity was improved about 65 folds to that of in current 25μl Ep-tube amplified reaction, which indicates a promising clinic molecular diagnostics in the droplet amplification.

Escala de Autoestima de Rosenberg (EAR: validade fatorial e consistência interna Rosenberg Self-Esteem Scale (RSS: factorial validity and internal consistency

Directory of Open Access Journals (Sweden)

Juliana Burges Sbicigo

2010-12-01

Full Text Available O objetivo deste estudo foi investigar as propriedades psicométricas da Escala de Autoestima de Rosenberg (EAR para adolescentes. Participaram 4.757 adolescentes, com idades entre 14 e 18 anos (M=15,77; DP=1,22, de nove cidades brasileiras. Os participantes responderam a uma versão da EAR adaptada para o Brasil. A análise fatorial exploratória apontou uma estrutura bidimensional, com 51.4% da variância explicada, que foi sustentada pela análise fatorial confirmatória. As análises de consistência interna realizadas por meio do coeficiente alfa de Cronbach, confiabilidade composta e variância extraída indicaram bons valores de fidedignidade. Diferenças nos escores de autoestima em função do sexo e da idade não foram encontradas. Conclui-se que a EAR apresenta qualidades psicométricas satisfatórias, mostrando-se um instrumento confiável para medir autoestima em adolescentes brasileiros.The aim of this study was to investigate the psychometrics properties of the Rosenberg Self-Esteem Scale (RSS for adolescents. The sample was composed of 4.757 adolescents, with ages between 14 and 18 years old (M=15.77; SD=1.22 in nine Brazilian cities. Participants responded to an adapted version of the RSS for Brazil. Exploratory factorial analysis showed a bidimensional structure, with 51.4% of explained variance. This result was supported by confirmatory factor analysis. The internal consistency analysis by Cronbach alpha coefficient, composite reliability and extracted variance indicated good reliability. Differences in self-esteem for gender and age were not found. These findings show that RSS has satisfactory psychometric qualities and it's a reliable instrument to assess self-esteem in Brazilian adolescents.

Nonlinear chemical sorption isotherms in the assessment of nuclear fuel waste disposal

International Nuclear Information System (INIS)

Walker, J.R.; LeNeveu, D.M.

1987-01-01

Radionuclides emplaced in an underground disposal vault can possibly migrate from the vault, and through the geosphere, to enter Man's environment. Chemical sorption is a primary mechanism for retarding this migration. The effects of nonlinear chemical sorption isotherms on radionuclide transport are discussed. A method is given by which nonlinear isotherms can be approximated by the linear sorption isotherm used in the vault submodel. The relevance of nonlinear isotherms to transport in the geosphere is discussed, and it is shown that the linear isotherm model is conservative for deep geologic disposal. 22 refs

Isothermal martensite formation at sub-zero temperatures

DEFF Research Database (Denmark)

Stojko, Allan; Hansen, Mikkel Fougt; Slycke, Jan

2012-01-01

, quenched in oil, and thereafter investigated with vibrating sample magnetometry, which allows a quantitative assessment of the fraction of retained austenite as a function of the sub-zero temperature and time. Isothermal martensite formation was observed on interrupting the continuous cooling (5 K...... with a continuation of the martensitic transformation. On prolonged isothermal holding, a volume reduction was observed for AISI 52100, but not for AISI 1070. Copyright © 2011 by ASTM International....

Water-Column Stratification Observed along an AUV-Tracked Isotherm

Science.gov (United States)

Zhang, Y.; Messié, M.; Ryan, J. P.; Kieft, B.; Stanway, M. J.; Hobson, B.; O'Reilly, T. C.; Raanan, B. Y.; Smith, J. M.; Chavez, F.

2016-02-01

Studies of marine physical, chemical and microbiological processes benefit from observing in a Lagrangian frame of reference, i.e. drifting with ambient water. Because these processes can be organized relative to specific density or temperature ranges, maintaining observing platforms within targeted environmental ranges is an important observing strategy. We have developed a novel method to enable a Tethys-class long-range autonomous underwater vehicle (AUV) (which has a propeller and a buoyancy engine) to track a target isotherm in buoyancy-controlled drift mode. In this mode, the vehicle shuts off its propeller and autonomously detects the isotherm and stays with it by actively controlling the vehicle's buoyancy. In the June 2015 CANON (Controlled, Agile, and Novel Observing Network) Experiment in Monterey Bay, California, AUV Makai tracked a target isotherm for 13 hours to study the coastal upwelling system. The tracked isotherm started from 33 m depth, shoaled to 10 m, and then deepened to 29 m. The thickness of the tracked isotherm layer (within 0.3°C error from the target temperature) increased over this duration, reflecting weakened stratification around the isotherm. During Makai's isotherm tracking, another long-range AUV, Daphne, acoustically tracked Makai on a circular yo-yo trajectory, measuring water-column profiles in Makai's vicinity. A wave glider also acoustically tracked Makai, providing sea surface measurements on the track. The presented method is a new approach for studying water-column stratification, but requires careful analysis of the temporal and spatial variations mingled in the vehicles' measurements. We will present a synthesis of the water column's stratification in relation to the upwelling conditions, based on the in situ measurements by the mobile platforms, as well as remote sensing and mooring data.

Riesz Representation Theorem on Bilinear Spaces of Truncated Laurent Series

Directory of Open Access Journals (Sweden)

Sabarinsyah

2017-06-01

Full Text Available In this study a generalization of the Riesz representation theorem on non-degenerate bilinear spaces, particularly on spaces of truncated Laurent series, was developed. It was shown that any linear functional on a non-degenerate bilinear space is representable by a unique element of the space if and only if its kernel is closed. Moreover an explicit equivalent condition can be identified for the closedness property of the kernel when the bilinear space is a space of truncated Laurent series.

Covariant density functional theory for decay of deformed proton emitters: A self-consistent approach

Directory of Open Access Journals (Sweden)

L.S. Ferreira

2016-02-01

Full Text Available Proton radioactivity from deformed nuclei is described for the first time by a self-consistent calculation based on covariant relativistic density functionals derived from meson exchange and point coupling models. The calculation provides an important new test to these interactions at the limits of stability, since the mixing of different angular momenta in the single particle wave functions is probed.

Binding Isotherms and Time Courses Readily from Magnetic Resonance.

Science.gov (United States)

Xu, Jia; Van Doren, Steven R

2016-08-16

Evidence is presented that binding isotherms, simple or biphasic, can be extracted directly from noninterpreted, complex 2D NMR spectra using principal component analysis (PCA) to reveal the largest trend(s) across the series. This approach renders peak picking unnecessary for tracking population changes. In 1:1 binding, the first principal component captures the binding isotherm from NMR-detected titrations in fast, slow, and even intermediate and mixed exchange regimes, as illustrated for phospholigand associations with proteins. Although the sigmoidal shifts and line broadening of intermediate exchange distorts binding isotherms constructed conventionally, applying PCA directly to these spectra along with Pareto scaling overcomes the distortion. Applying PCA to time-domain NMR data also yields binding isotherms from titrations in fast or slow exchange. The algorithm readily extracts from magnetic resonance imaging movie time courses such as breathing and heart rate in chest imaging. Similarly, two-step binding processes detected by NMR are easily captured by principal components 1 and 2. PCA obviates the customary focus on specific peaks or regions of images. Applying it directly to a series of complex data will easily delineate binding isotherms, equilibrium shifts, and time courses of reactions or fluctuations.

Pressure-sensitive paint on a truncated cone in hypersonic flow at incidences

International Nuclear Information System (INIS)

Yang, L.; Erdem, E.; Zare-Behtash, H.; Kontis, K.; Saravanan, S.

2012-01-01

Highlights: ► Global pressure map over the truncated cone is obtained at various incidence angles in Mach 5 flow. ► Successful application of AA-PSP in hypersonic flow expands operation area of this technique. ► AA-PSP reveals complex three-dimensional pattern which is difficult for transducer to obtain. ► Quantitative data provides strong correlation with colour Schlieren and oil flow results. ► High spatial resolution pressure mappings identify small scale vortices and flow separation. - Abstract: The flow over a truncated cone is a classical and fundamental problem for aerodynamic research due to its three-dimensional and complicated characteristics. The flow is made more complex when examining high angles of incidence. Recently these types of flows have drawn more attention for the purposes of drag reduction in supersonic/hypersonic flows. In the present study the flow over a truncated cone at various incidences was experimentally investigated in a Mach 5 flow with a unit Reynolds number of 13.5 × 10 6 m −1 . The cone semi-apex angle is 15° and the truncation ratio (truncated length/cone length) is 0.5. The incidence of the model varied from −12° to 12° with 3° intervals relative to the freestream direction. The external flow around the truncated cone was visualised by colour Schlieren photography, while the surface flow pattern was revealed using the oil flow method. The surface pressure distribution was measured using the anodized aluminium pressure-sensitive paint (AA-PSP) technique. Both top and sideviews of the pressure distribution on the model surface were acquired at various incidences. AA-PSP showed high pressure sensitivity and captured the complicated flow structures which correlated well with the colour Schlieren and oil flow visualisation results.

Self-consistent model for pulsed direct-current N2 glow discharge

International Nuclear Information System (INIS)

Liu Chengsen

2005-01-01

A self-consistent analysis of a pulsed direct-current (DC) N 2 glow discharge is presented. The model is based on a numerical solution of the continuity equations for electron and ions coupled with Poisson's equation. The spatial-temporal variations of ionic and electronic densities and electric field are obtained. The electric field structure exhibits all the characteristic regions of a typical glow discharge (the cathode fall, the negative glow, and the positive column). Current-voltage characteristics of the discharge can be obtained from the model. The calculated current-voltage results using a constant secondary electron emission coefficient for the gas pressure 133.32 Pa are in reasonable agreement with experiment. (authors)

Longitudinal halo in beam bunches with self-consistent 6-D distributions

International Nuclear Information System (INIS)

Gluckstern, R. L.; Fedotov, A. V.; Kurennoy, S. S.; Ryne, R. D.

1998-01-01

We have explored the formation of longitudinal and transverse halos in 3-D axisymmetric beam bunches by starting with a self-consistent 6-D phase space distribution. Stationary distributions allow us to study the halo development mechanism without being obscured by beam redistribution and its effect on halo formation. The beam is then mismatched longitudinally and/or transversely, and we explore the rate, intensity and spatial extent of the halos which form, as a function of the beam charge and the mismatches. We find that the longitudinal halo forms first because the longitudinal tune depression is more severe than the transverse one for elongated bunches and conclude that it plays a major role in halo formation

Financial Statement Audit Report of Isothermal Community College.

Science.gov (United States)

Campbell, Ralph

This report presents the results of the Isothermal Community College financial statement audit for the fiscal year ending on June 30, 1998. Isothermal Community College is a component of the State of North Carolina, thus the authority to audit is granted by Article 5A of G.S. 147. The accounts and operations of the institution were subject to…

Assessment of Salmonella spp. and Escherichia coli O157:H7 growth on lettuce exposed to isothermal and non-isothermal conditions.

Science.gov (United States)

de Oliveira Elias, Susana; Noronha, Tiago Baptista; Tondo, Eduardo Cesar

2018-06-01

This study aimed to assess the growth of Salmonella and Escherichia coli O157:H7 on lettuce exposed to isothermal and non-isothermal conditions. Pathogens were inoculated on lettuce separately and stored under isothermal condition at 5 °C, 10 °C, 25 °C, 37 °C for both bacteria, at 40 °C for Salmonella and 42 °C for E. coli O157:H7. Growth curves were built by fitting the data to the Baranyi's DMFit, generating R 2 values greater than 0.92 for primary models. Secondary models were fitted with Ratkowsky equations, generating R 2 values higher than 0.91 and RMSE lower than 0.1. Experimental data showed that both bacteria could grow at all temperatures. Also, the growth of both pathogens under non-isothermal conditions was studied simulating temperatures found from harvest to supermarkets in Brazil. Models were analysed by R 2 , RMSE, bias factor (Bf) and accuracy factor (Af). Salmonella and E. coli O157:H7 were able to grow in this temperature profile and the models could predict the behavior of these microorganisms on lettuce under isothermal and non-isothermal conditions. Based on the results, a negligible growth time (ς) was proposed to provide the time which lettuce could be exposed to a specific temperature and do not present an expressive growth of bacteria. The ς was developed based on Baranyi's primary model equation and on growth potential concept. ς is the value of lag phase added of the time necessary to population grow 0.5 log CFU/g. The ς of lettuce exposed to 37 °C was 1.3 h, while at 5 °C was 3.3 days. Copyright © 2017 Elsevier Ltd. All rights reserved.

On truncations of the exact renormalization group

CERN Document Server

Morris, T R

1994-01-01

We investigate the Exact Renormalization Group (ERG) description of (Z_2 invariant) one-component scalar field theory, in the approximation in which all momentum dependence is discarded in the effective vertices. In this context we show how one can perform a systematic search for non-perturbative continuum limits without making any assumption about the form of the lagrangian. Concentrating on the non-perturbative three dimensional Wilson fixed point, we then show that the sequence of truncations n=2,3,\\dots, obtained by expanding about the field \\varphi=0 and discarding all powers \\varphi^{2n+2} and higher, yields solutions that at first converge to the answer obtained without truncation, but then cease to further converge beyond a certain point. No completely reliable method exists to reject the many spurious solutions that are also found. These properties are explained in terms of the analytic behaviour of the untruncated solutions -- which we describe in some detail.

Multifractality and quantum diffusion from self-consistent theory of localization

Energy Technology Data Exchange (ETDEWEB)

Suslov, I. M., E-mail: suslov@kapitza.ras.ru [Kapitza Institute for Physical Problems (Russian Federation)

2015-11-15

Multifractal properties of wave functions in a disordered system can be derived from self-consistent theory of localization by Vollhardt and Wölfle. A diagrammatic interpretation of results allows to obtain all scaling relations used in numerical experiments. The arguments are given that the one-loop Wegner result for a space dimension d = 2 + ϵ is exact, so the multifractal spectrum is strictly parabolical. The σ-models are shown to be deficient at the four-loop level and the possible reasons of that are discussed. The extremely slow convergence to the thermodynamic limit is demonstrated. The open question on the relation between multifractality and a spatial dispersion of the diffusion coefficient D(ω, q) is resolved in the compromise manner due to ambiguity of the D(ω, q) definition. Comparison is made with the extensive numerical material.

Improved Isotherm Data for Adsorption of Methane on Activated Carbons

KAUST Repository

Loh, Wai Soong

2010-08-12

This article presents the adsorption isotherms of methane onto two different types of activated carbons, namely, Maxsorb III and ACF (A-20) at temperatures from (5 to 75) °C and pressures up to 2.5 MPa. The volumetric technique has been employed to measure the adsorption isotherms. The experimental results presented herein demonstrate the improved accuracy of the uptake values compared with previous measurement techniques for similar adsorbate-adsorbent combinations. The results are analyzed with various adsorption isotherm models. The heat of adsorption, which is concentration and temperature dependent, has been calculated from the measured isotherm data. Henry\\'s law coefficients for these adsorbent-methane pairs are also evaluated at various temperatures. © 2010 American Chemical Society.

Longitudinal motion in high current ion beams: a self-consistent phase space distribution with an envelope equation

International Nuclear Information System (INIS)

Neuffer, D.

1979-03-01

Many applications of particle acceleration, such as heavy ion fusion, require longitudinal bunching of a high intensity particle beam to extremely high particle currents with correspondingly high space charge forces. This requires a precise analysis of longitudinal motion including stability analysis. Previous papers have treated the longitudinal space charge force as strictly linear, and have not been self-consistent; that is, they have not displayed a phase space distribution consistent with this linear force so that the transport of the phase space distribution could be followed, and departures from linearity could be analyzed. This is unlike the situation for transverse phase space where the Kapchinskij--Vladimirskij (K--V) distribution can be used as the basis of an analysis of transverse motion. In this paper a self-consistent particle distribution in longitudinal phase space is derived which is a solution of the Vlasov equation and an envelope equation for this solution is derived

Development of a self-consistent lightning NOx simulation in large-scale 3-D models

Science.gov (United States)

Luo, Chao; Wang, Yuhang; Koshak, William J.

2017-03-01

We seek to develop a self-consistent representation of lightning NOx (LNOx) simulation in a large-scale 3-D model. Lightning flash rates are parameterized functions of meteorological variables related to convection. We examine a suite of such variables and find that convective available potential energy and cloud top height give the best estimates compared to July 2010 observations from ground-based lightning observation networks. Previous models often use lightning NOx vertical profiles derived from cloud-resolving model simulations. An implicit assumption of such an approach is that the postconvection lightning NOx vertical distribution is the same for all deep convection, regardless of geographic location, time of year, or meteorological environment. Detailed observations of the lightning channel segment altitude distribution derived from the NASA Lightning Nitrogen Oxides Model can be used to obtain the LNOx emission profile. Coupling such a profile with model convective transport leads to a more self-consistent lightning distribution compared to using prescribed postconvection profiles. We find that convective redistribution appears to be a more important factor than preconvection LNOx profile selection, providing another reason for linking the strength of convective transport to LNOx distribution.

Self-Consistent Monte Carlo Study of the Coulomb Interaction under Nano-Scale Device Structures

Science.gov (United States)

Sano, Nobuyuki

2011-03-01

It has been pointed that the Coulomb interaction between the electrons is expected to be of crucial importance to predict reliable device characteristics. In particular, the device performance is greatly degraded due to the plasmon excitation represented by dynamical potential fluctuations in high-doped source and drain regions by the channel electrons. We employ the self-consistent 3D Monte Carlo (MC) simulations, which could reproduce both the correct mobility under various electron concentrations and the collective plasma waves, to study the physical impact of dynamical potential fluctuations on device performance under the Double-gate MOSFETs. The average force experienced by an electron due to the Coulomb interaction inside the device is evaluated by performing the self-consistent MC simulations and the fixed-potential MC simulations without the Coulomb interaction. Also, the band-tailing associated with the local potential fluctuations in high-doped source region is quantitatively evaluated and it is found that the band-tailing becomes strongly dependent of position in real space even inside the uniform source region. This work was partially supported by Grants-in-Aid for Scientific Research B (No. 2160160) from the Ministry of Education, Culture, Sports, Science and Technology in Japan.

Adsorption isotherms of pear at several temperatures

OpenAIRE

Mitrevski Vangelče; Lutovska Monika; Mijakovski Vladimir; Pavkov Ivan S.; Babić Mirko M.; Radojčin Milivoje T.

2015-01-01

The moisture adsorption isotherms of pear were determined at 15ºC, 30ºC and 45ºC using the standard static gravimetric method over a range of water activity from 0.112 to 0.920. The experimental data were fitted with isotherm equations recommended in ASAE Standard D245.5. In order to find which equation gives the best results, large number of numerical experiments were performed. After that, several statistical criteria proposed in scientific literature for...

Resonant Excitation of a Truncated Metamaterial Cylindrical Shell by a Thin Wire Monopole

DEFF Research Database (Denmark)

Kim, Oleksiy S.; Erentok, Aycan; Breinbjerg, Olav

2009-01-01

A truncated metamaterial cylindrical shell excited by a thin wire monopole is investigated using the integral equation technique as well as the finite element method. Simulations reveal a strong field singularity at the edge of the truncated cylindrical shell, which critically affects the matching...

An Isothermal Steam Expander for an Industrial Steam Supplying System

Directory of Open Access Journals (Sweden)

Chen-Kuang Lin

2015-01-01

Full Text Available Steam is an essential medium used in the industrial process. To ensure steam quality, small and middle scale boilers are often adopted. However, because a higher steam pressure (compared to the necessary steam pressure is generated, the boiler’s steam pressure will be reduced via a pressure regulator before the steam is directed through the process. Unfortunately, pressure is somewhat wasted during the reducing process. Therefore, in order to promote energy efficiency, a pressure regulator is replaced by a steam expander. With this steam expander, the pressure will be transformed into mechanical energy and extracted during the expansion process. A new type of isothermal steam expander for an industrial steam supplying system will be presented in the paper. The isothermal steam expander will improve the energy efficiency of a traditional steam expander by replacing the isentropic process with an isothermal expansion process. With this, steam condensation will decrease, energy will increase, and steam quality will be improved. Moreover, the mathematical model of the isothermal steam expander will be established by using the Schmidt theory, the same principle used to analyze Stirling engines. Consequently, by verifying the correctness of the theoretical model for the isothermal steam expander using experimental data, a prototype of 100 c.c. isothermal steam expander is constructed.

Coronal Loops: Evolving Beyond the Isothermal Approximation

Science.gov (United States)

Schmelz, J. T.; Cirtain, J. W.; Allen, J. D.

2002-05-01

Are coronal loops isothermal? A controversy over this question has arisen recently because different investigators using different techniques have obtained very different answers. Analysis of SOHO-EIT and TRACE data using narrowband filter ratios to obtain temperature maps has produced several key publications that suggest that coronal loops may be isothermal. We have constructed a multi-thermal distribution for several pixels along a relatively isolated coronal loop on the southwest limb of the solar disk using spectral line data from SOHO-CDS taken on 1998 Apr 20. These distributions are clearly inconsistent with isothermal plasma along either the line of sight or the length of the loop, and suggested rather that the temperature increases from the footpoints to the loop top. We speculated originally that these differences could be attributed to pixel size -- CDS pixels are larger, and more `contaminating' material would be expected along the line of sight. To test this idea, we used CDS iron line ratios from our data set to mimic the isothermal results from the narrowband filter instruments. These ratios indicated that the temperature gradient along the loop was flat, despite the fact that a more complete analysis of the same data showed this result to be false! The CDS pixel size was not the cause of the discrepancy; rather, the problem lies with the isothermal approximation used in EIT and TRACE analysis. These results should serve as a strong warning to anyone using this simplistic method to obtain temperature. This warning is echoed on the EIT web page: ``Danger! Enter at your own risk!'' In other words, values for temperature may be found, but they may have nothing to do with physical reality. Solar physics research at the University of Memphis is supported by NASA grant NAG5-9783. This research was funded in part by the NASA/TRACE MODA grant for Montana State University.

Squeezing in multi-mode nonlinear optical state truncation

International Nuclear Information System (INIS)

Said, R.S.; Wahiddin, M.R.B.; Umarov, B.A.

2007-01-01

In this Letter, we show that multi-mode qubit states produced via nonlinear optical state truncation driven by classical external pumpings exhibit squeezing condition. We restrict our discussions to the two- and three-mode cases

The Plumber’s Nightmare Phase in Diblock Copolymer/Homopolymer Blends. A Self-Consistent Field Theory Study.

KAUST Repository

Martinez-Veracoechea, Francisco J.; Escobedo, Fernando A.

2009-01-01

Using self-consistent field theory, the Plumber's Nightmare and the double diamond phases are predicted to be stable in a finite region of phase diagrams for blends of AB diblock copolymer (DBC) and A-component homopolymer. To the best of our

Self-consistent approach for neutral community models with speciation

Science.gov (United States)

Haegeman, Bart; Etienne, Rampal S.

2010-03-01

Hubbell’s neutral model provides a rich theoretical framework to study ecological communities. By incorporating both ecological and evolutionary time scales, it allows us to investigate how communities are shaped by speciation processes. The speciation model in the basic neutral model is particularly simple, describing speciation as a point-mutation event in a birth of a single individual. The stationary species abundance distribution of the basic model, which can be solved exactly, fits empirical data of distributions of species’ abundances surprisingly well. More realistic speciation models have been proposed such as the random-fission model in which new species appear by splitting up existing species. However, no analytical solution is available for these models, impeding quantitative comparison with data. Here, we present a self-consistent approximation method for neutral community models with various speciation modes, including random fission. We derive explicit formulas for the stationary species abundance distribution, which agree very well with simulations. We expect that our approximation method will be useful to study other speciation processes in neutral community models as well.

Nuclear charge-exchange excitations in a self-consistent covariant approach

International Nuclear Information System (INIS)

Liang, Haozhao

2010-01-01

Nowadays, charge-exchange excitations in nuclei become one of the central topics in nuclear physics and astrophysics. Basically, a systematic pattern of the energy and collectivity of these excitations could provide direct information on the spin and isospin properties of the in-medium nuclear interaction, and the equation of state of asymmetric nuclear matter. Furthermore, a basic and critical quantity in nuclear structure, neutron skin thickness, can be determined indirectly by the sum rule of spin-dipole resonances (SDR) or the excitation energy spacing between the isobaric analog states (IAS) and Gamow-Teller resonances (GTR). More generally, charge-exchange excitations allow one to attack other kinds of problems outside the realm of nuclear structure, like the description of neutron star and supernova evolutions, the β-decay of nuclei which lie on the r-process path of stellar nucleosynthesis, and the neutrino-nucleus cross sections. They also play an essential role in extracting the value of the Cabibbo-Kobayashi-Maskawa (CKM) matrix element V ud via the nuclear 0 + → 0 + superallowed Fermi β decays. For all these reasons, it is important to develop the microscopic theories of charge-exchange excitations and it is the main motivation of the present work. In this work, a fully self-consistent charge-exchange relativistic random phase approximation (RPA) based on the relativistic Hartree-Fock (RHF) approach is established. Its self-consistency is verified by the so-called IAS check. This approach is then applied to investigate the nuclear spin-isospin resonances, isospin symmetry-breaking corrections for the superallowed β decays, and the charged-current neutrino-nucleus cross sections. For two important spin-isospin resonances, GTR and SDR, it is shown that a very satisfactory agreement with the experimental data can be obtained without any readjustment of the energy functional. Furthermore, the isoscalar mesons are found to play an essential role in spin

Effect of the isothermal transformation temperature on the fine structure of steel-12Kh1MF

International Nuclear Information System (INIS)

Mints, I.I.; Berezina, T.G.; Lanskaya, K.A.

1976-01-01

For detailed analysis of bainite and pearlite in steel 12Kh1MF, homogeneous structures were obtained by isothermal annealing at 350, 450, 500, and 650 0 for 1 h. Isothermal transformation of austenite leads to the formation of bainite at 350-500 0 and pearlite at 650 0 . The austenitizing temperature was 980 0 for both types of samples, with holding for 20 min. For comparison, the plates were quenched from 980 0 and 1050 0 in ice-cold brine. The investigation was conducted with use of light and electron microscopes and x-ray analysis. The long-term strength was also determined. Isothermal treatment of steel 12Kh1MF at 350-500 0 C leads to the formation of a structure consisting of upper and lower bainite. At 500 0 the structure consists primarily of upper bainite, and at 350 0 of lower bainite. With tempering of the steel with a structure of upper and lower bainite at 730 0 for 3 h the dislocations undergo redistribution of the polygonization type within ferrite needles, with development of a cellular substructure. The acicular structure of the matrix is retained in this case. The density and evenness of the distribution of carbides is higher in upper bainite than in lower bainite. Steel 12Kh1MF with a structure of upper bainite is more susceptible to recrystallization as compared with a structure of lower bainite, which is responsible for the higher heat resistance of the latter

Self-consistent Maxwell-Bloch model of quantum-dot photonic-crystal-cavity lasers

DEFF Research Database (Denmark)

Cartar, William; Mørk, Jesper; Hughes, Stephen

2017-01-01

-level emitters are solved numerically. Phenomenological pure dephasing and incoherent pumping is added to the optical Bloch equations to allow for a dynamical lasing regime, but the cavity-mediated radiative dynamics and gain coupling of each QD dipole (artificial atom) is contained self-consistently within......-mode to multimode lasing is also observed, depending on the spectral peak frequency of the QD ensemble. Using a statistical modal analysis of the average decay rates, we also show how the average radiative decay rate decreases as a function of cavity size. In addition, we investigate the role of structural disorder...

Interstellar turbulence model : A self-consistent coupling of plasma and neutral fluids

International Nuclear Information System (INIS)

Shaikh, Dastgeer; Zank, Gary P.; Pogorelov, Nikolai

2006-01-01

We present results of a preliminary investigation of interstellar turbulence based on a self-consistent two-dimensional fluid simulation model. Our model describes a partially ionized magnetofluid interstellar medium (ISM) that couples a neutral hydrogen fluid to a plasma through charge exchange interactions and assumes that the ISM turbulent correlation scales are much bigger than the shock characteristic length-scales, but smaller than the charge exchange mean free path length-scales. The shocks have no influence on the ISM turbulent fluctuations. We find that nonlinear interactions in coupled plasma-neutral ISM turbulence are influenced substantially by charge exchange processes

Experimental and Numerical Studies on Isothermal and Non-isothermal Deep Drawing of IS 513 CR3 Steel Sheets

Science.gov (United States)

Mayavan, T.; Karthikeyan, L.; Senthilkumar, V. S.

2016-11-01

The present work aims to investigate the effects of the temperature gradient developed within the tool profiles on the formability of IS 513 CR3-grade steel sheets using the cup drawing test. The deformation characteristics of steel sheets were analyzed by comparing the thicknesses in various regions of the formed cup and also the limiting drawing ratios (LDR). Finite element simulations were carried out to predict the behavior of the steel sheets in isothermal and non-isothermal forming using Abaqus/Standard 6.12-1. An analytical model created by Kim was used to validate the experimental and finite element analysis (FEA) results on identical process parameters. Both the FEA and analytical modeling results showed that formability improvement is possible in warm forming; the findings are in good agreement with the experimental results in determining the locations and values of excessive thinning. The results also indicated that formability improvement cannot be achieved by keeping the tooling temperature at the same level. The LDR increased by around 9.5% in isothermal forming and by 19% in non-isothermal forming (with the punch maintained at a lower temperature compared with the die and blank holder). In addition, the fractured surfaces of unsuccessfully formed samples were analyzed using scanning electron microscopy. Metallographic investigations confirmed that the fracture mechanism during the forming of IS 513 CR3-grade steel sheets depends on the brittleness, strain hardening value, forming temperature, and magnitude of stresses developed.

truncSP: An R Package for Estimation of Semi-Parametric Truncated Linear Regression Models

Directory of Open Access Journals (Sweden)

Maria Karlsson

2014-05-01

Full Text Available Problems with truncated data occur in many areas, complicating estimation and inference. Regarding linear regression models, the ordinary least squares estimator is inconsistent and biased for these types of data and is therefore unsuitable for use. Alternative estimators, designed for the estimation of truncated regression models, have been developed. This paper presents the R package truncSP. The package contains functions for the estimation of semi-parametric truncated linear regression models using three different estimators: the symmetrically trimmed least squares, quadratic mode, and left truncated estimators, all of which have been shown to have good asymptotic and ?nite sample properties. The package also provides functions for the analysis of the estimated models. Data from the environmental sciences are used to illustrate the functions in the package.

Isoscalar and isovector giant resonances in a self-consistent phonon coupling approach

Energy Technology Data Exchange (ETDEWEB)

Lyutorovich, N.; Tselyaev, V. [Physical Faculty, St. Petersburg State University, RU-198504 St. Petersburg (Russian Federation); Speth, J., E-mail: J.Speth@fz-juelich.de [Institut für Kernphysik, Forschungszentrum Jülich, D-52425 Jülich (Germany); Krewald, S.; Grümmer, F. [Institut für Kernphysik, Forschungszentrum Jülich, D-52425 Jülich (Germany); Reinhard, P.-G. [Institut für Theoretische Physik II, Universität Erlangen-Nürnberg, D-91058 Erlangen (Germany)

2015-10-07

We present fully self-consistent calculations of isoscalar giant monopole and quadrupole as well as isovector giant dipole resonances in heavy and light nuclei. The description is based on Skyrme energy-density functionals determining the static Hartree–Fock ground state and the excitation spectra within random-phase approximation (RPA) and RPA extended by including the quasiparticle-phonon coupling at the level of the time-blocking approximation (TBA). All matrix elements were derived consistently from the given energy-density functional and calculated without any approximation. As a new feature in these calculations, the single-particle continuum was included thus avoiding the artificial discretization usually implied in RPA and TBA. The step to include phonon coupling in TBA leads to small, but systematic, down shifts of the centroid energies of the giant resonances. These shifts are similar in size for all Skyrme parametrizations investigated here. After all, we demonstrate that one can find Skyrme parametrizations which deliver a good simultaneous reproduction of all three giant resonances within TBA.