General theory for thermal pulses of finite amplitude in nuclear shell-burnings

Energy Technology Data Exchange (ETDEWEB)

Sugimoto, D [Tokyo Univ. (Japan). Coll. of General Education; Fujimoto, M Y

1978-09-01

Theory for thermal pulses of nuclear shell-burning is advanced to include the case of finite amplitude. The aims are to predict the progress of thermal pulse quantitatively and to obtain the peak values of the temperature and nuclear energy generation rate without making detailed numerical computation of stellar structure. In order to attain them the physical processes involved in the progress of the pulse are clarified using the concepts of the flatness of the shell source, which destabilizes nuclear burning, and the effect of radiation pressure, which stabilizes it. It is shown that the progress of the pulse can be predicted quantitatively when the pressure and the gravitational potential of the burning shell are specified for the onset stage of the pulse. The pulse height is determined mainly by the initial pressure; the higher initial pressure results in the higher pulse. Mass dependence is also obtained by approximating the gravitational potential by that of white dwarfs. The initial pressure is the quantity which is determined in the course of evolution preceding the pulse. The theory is shown to give a satisfactory agreement with numerical computations for a wide variety of the preceding evolutions, i.e., both for the case of the core in red giant stars and of the accreting white dwarfs.

SU(5) finite unified theories and the mass of the top quark

International Nuclear Information System (INIS)

Mondragon, M.; Zoupanos, G.

1994-01-01

We present results of a study of phenomenologically interesting SU(5) supersymmetric GUT's, which are finite to all-loops before spontaneous symmetry breaking. The finiteness conditions provide the spontaneously broken theory with relationships among the Yukawa and gauge couplings at the unification point. These in turn predict a heavy top quark mass (∼175-190 GeV). (orig.)

Nuclear collective states at finite temperature

International Nuclear Information System (INIS)

Milian, A.; Barranco, M.; Mas, D.; Lombard, R.J.

1987-04-01

The Energy Density Method (EDM) has been used to study low-lying nuclear collective states as well as isoscalar giant resonances at finite temperature (T). Giant states have been studied by computing the corresponding strength function moments (sum rules) in the Random-Phase Approximation (RPA). For the description of the low lying states we have resorted to a variety of models from the rather sophisticated RPA method to liquid drop and schematic models. It has been found that low lying states are most affected by thermal effects, giant resonances being little affected in the range of temperatures here studied

Critical assessment of nuclear mass models

International Nuclear Information System (INIS)

Moeller, P.; Nix, J.R.

1992-01-01

Some of the physical assumptions underlying various nuclear mass models are discussed. The ability of different mass models to predict new masses that were not taken into account when the models were formulated and their parameters determined is analyzed. The models are also compared with respect to their ability to describe nuclear-structure properties in general. The analysis suggests future directions for mass-model development

Measuring the strangeness content of the nucleon by observing the ϕ-meson mass shift in nuclear matter

International Nuclear Information System (INIS)

Gubler, Philipp; Ohtani, Keisuke

2015-01-01

The modification of the ϕ-meson at finite density is studied by using QCD sum rules in combination with the maximum entropy method. As a result, it is found that the mass shift of the ϕ-meson is strongly correlated to the strangeness content of the nucleon, , which governs the depletion of the strange quark condensate in nuclear matter. (author)

Mass Spectrometric Analysis for Nuclear Safeguards

International Nuclear Information System (INIS)

Boulyga, S.

2013-01-01

The release of man-made radionuclides into the environment results in contamination that carries specific isotopic signatures according to the release scenarios and the previous usage of materials and facilities. In order to trace the origin of such contamination and/or to assess the potential impact on the public and environmental health, it is necessary to determine the isotopic composition and activity concentrations of radionuclides in environmental samples in an accurate and timely fashion. Mass spectrometric techniques, such as thermal ionization mass spectrometry (TIMS), secondary ion mass spectrometry (SIMS), and inductively coupled plasma mass spectrometry (ICP-MS) belong to the most powerful methods for analysis of nuclear and related samples in nuclear safeguards, forensics, and environmental monitoring. This presentation will address the potential of mass spectrometric analysis of actinides at ultra-trace concentration levels, isotopic analysis of micro-samples, age determination of nuclear materials as well as identification and quantification of elemental and isotopic signatures of nuclear samples in general. (author)

Coupled porohyperelastic mass transport (PHEXPT) finite element models for soft tissues using ABAQUS.

Science.gov (United States)

Vande Geest, Jonathan P; Simon, B R; Rigby, Paul H; Newberg, Tyler P

2011-04-01

Finite element models (FEMs) including characteristic large deformations in highly nonlinear materials (hyperelasticity and coupled diffusive/convective transport of neutral mobile species) will allow quantitative study of in vivo tissues. Such FEMs will provide basic understanding of normal and pathological tissue responses and lead to optimization of local drug delivery strategies. We present a coupled porohyperelastic mass transport (PHEXPT) finite element approach developed using a commercially available ABAQUS finite element software. The PHEXPT transient simulations are based on sequential solution of the porohyperelastic (PHE) and mass transport (XPT) problems where an Eulerian PHE FEM is coupled to a Lagrangian XPT FEM using a custom-written FORTRAN program. The PHEXPT theoretical background is derived in the context of porous media transport theory and extended to ABAQUS finite element formulations. The essential assumptions needed in order to use ABAQUS are clearly identified in the derivation. Representative benchmark finite element simulations are provided along with analytical solutions (when appropriate). These simulations demonstrate the differences in transient and steady state responses including finite deformations, total stress, fluid pressure, relative fluid, and mobile species flux. A detailed description of important model considerations (e.g., material property functions and jump discontinuities at material interfaces) is also presented in the context of finite deformations. The ABAQUS-based PHEXPT approach enables the use of the available ABAQUS capabilities (interactive FEM mesh generation, finite element libraries, nonlinear material laws, pre- and postprocessing, etc.). PHEXPT FEMs can be used to simulate the transport of a relatively large neutral species (negligible osmotic fluid flux) in highly deformable hydrated soft tissues and tissue-engineered materials.

A low-energy β-function in a finite super-Yang-Mills model with multiple mass scales

International Nuclear Information System (INIS)

Foda, O.; Helayel-Neto, J.A.

1985-01-01

We compute the one-loop contribution to the low-energy light-fermion gauge coupling in a finite supersymmetric gauge theory with two mass scales: a heavy mass that breaks an initial N=4 supersymmetry down to N=2, but respects the finiteness, and a light mass that, for simplicity, is set to zero. We find that coupling grows with the mass of the heavy intermediate states. Hence the latter do not decouple at low energies, leading to large logarithms that invalidate low-energy perturbation theory. Consequently, further manipulations are required to obtain a meaningful perturbative expansion. Enforcing decoupling through finite renormalizations, that absorb the heavy mass effects into a redefinition of the parameters of the lagrangian, introduces an arbitrary subtraction mass μ. The requirement that the S-matrix elements be independent of μ leads to a non-trivial renormalization-group equation for the low-energy theory, with a non-vanishing β-function. (orig.)

A low-energy β-function in a finite super-Yang-Mills model with multiple mass scales

International Nuclear Information System (INIS)

Foda, O.; Helayel-Neto, J.A.

1984-08-01

We compute the one-loop contribution to the low-energy light-fermion gauge coupling in a finite supersymmetric gauge theory with two mass scales: a heavy mass that breaks an initial N=4 supersymmetry down to N=2, but respects the finiteness, and a light mass that, for simplicity, is set to zero. We find that the coupling grows with the mass of the heavy intermediate states. Hence the latter do not decouple at low energies, leading to large logarithms that invalidate low-energy perturbation theory. Consequently, further manipulations are required to obtain a meaningful perturbative expansion. Enforcing decoupling through finite renormalizations, that absorb the heavy mass effects into a redefinition of the parameters of the Lagrangian, introduces an arbitrary subtraction mass μ. The requirement that the S-matrix elements be independent of μ leads to a non-trivial renormalization-group equation for the low-energy theory, with a non-vanishing β-function. (author)

Nuclear mass formula with a neutron skin degree of freedom and finite-range model for the surface energy

International Nuclear Information System (INIS)

Moeller, P.; Myers, W.D.

1984-03-01

We study the possibility of extending the model used by Moeller and Nix in 1980 to calculate nuclear masses and fission barriers for nuclei throughout the periodic system, to describe compressibility effects and the existence of a neutron skin. 9 references

Quantum chaos and nuclear mass systematics

International Nuclear Information System (INIS)

Hirsch, Jorge G.; Velazquez, Victor; Frank, Alejandro

2004-01-01

The presence of quantum chaos in nuclear mass systematics is analyzed by considering the differences between measured and calculated nuclear masses as a time series described by the power law 1fα. While for the liquid droplet model plus shell corrections a quantum chaotic behavior α∼1 is found, errors in the microscopic mass formula have α∼0.5, closer to white noise. The chaotic behavior seems to arise from many body effects not included in the mass formula

Nuclear mass formula with a neutron skin degree of freedom and finite-range model for the surface energy

Energy Technology Data Exchange (ETDEWEB)

Moeller, P.; Myers, W.D.

1984-03-01

We study the possibility of extending the model used by Moeller and Nix in 1980 to calculate nuclear masses and fission barriers for nuclei throughout the periodic system, to describe compressibility effects and the existence of a neutron skin. 9 references. (WHK)

Non-perturbative Debye mass in finite-T QCD

CERN Document Server

Kajantie, Keijo; Peisa, J; Rajantie, A; Rummukainen, K; Shaposhnikov, Mikhail E

1997-01-01

Employing a non-perturbative gauge invariant definition of the Debye screening mass m_D in the effective field theory approach to finite T QCD, we use 3d lattice simulations to determine the leading O(g^2) and to estimate the next-to-leading O(g^3) corrections to m_D in the high temperature region. The O(g^2) correction is large and modifies qualitatively the standard power-counting hierarchy picture of correlation lengths in high temperature QCD.

$J/\\Psi$ mass shift in nuclear matter

Energy Technology Data Exchange (ETDEWEB)

Gastao Krein, Anthony Thomas, Kazuo Tsushima

2011-02-01

The $J/\\Psi$ mass shift in cold nuclear matter is computed using an effective Lagrangian approach. The mass shift is computed by evaluating $D$ and $D^*$ meson loop contributions to the $J/\\Psi$ self-energy employing medium-modified meson masses. The modification of the $D$ and $D^*$ masses in nuclear matter is obtained using the quark-meson coupling model. The loop integrals are regularized with dipole form factors and the sensitivity of the results to the values of form-factor cutoff masses is investigated. The $J/\\Psi$ mass shift arising from the modification of the $D$ and $D^*$ loops at normal nuclear matter density is found to range from $-16$~MeV to $-24$~MeV under a wide variation of values of the cutoff masses. Experimental perspectives for the formation of a bound state of $J/\\Psi$ to a nucleus are investigated.

Finite size effects in neutron star and nuclear matter simulations

Energy Technology Data Exchange (ETDEWEB)

Giménez Molinelli, P.A., E-mail: pagm@df.uba.ar; Dorso, C.O.

2015-01-15

In this work we study molecular dynamics simulations of symmetric nuclear and neutron star matter using a semi-classical nucleon interaction model. Our aim is to gain insight on the nature of the so-called “finite size effects”, unavoidable in this kind of simulations, and to understand what they actually affect. To do so, we explore different geometries for the periodic boundary conditions imposed on the simulation cell: cube, hexagonal prism and truncated octahedron. For nuclear matter simulations we show that, at sub-saturation densities and low temperatures, the solutions are non-homogeneous structures reminiscent of the “nuclear pasta” phases expected in neutron star matter simulations, but only one structure per cell and shaped by specific artificial aspects of the simulations—for the same physical conditions (i.e. number density and temperature) different cells yield different solutions. The particular shape of the solution at low enough temperature and a given density can be predicted analytically by surface minimization. We also show that even if this behavior is due to the imposition of periodic boundary conditions on finite systems, this does not mean that it vanishes for very large systems, and it is actually independent of the system size. We conclude that, for nuclear matter simulations, the cells' size sets the only characteristic length scale for the inhomogeneities, and the geometry of the periodic cell determines the shape of those inhomogeneities. To model neutron star matter we add a screened Coulomb interaction between protons, and perform simulations in the three cell geometries. Our simulations indeed produce the well known nuclear pasta, with (in most cases) several structures per cell. However, we find that for systems not too large results are affected by finite size in different ways depending on the geometry of the cell. In particular, at the same certain physical conditions and system size, the hexagonal prism yields a

Plasma Mass Filters For Nuclear Waste Reprocessing

International Nuclear Information System (INIS)

Fetterman, Abraham J.; Fisch, Nathaniel J.

2011-01-01

Practical disposal of nuclear waste requires high-throughput separation techniques. The most dangerous part of nuclear waste is the fission product, which contains the most active and mobile radioisotopes and produces most of the heat. We suggest that the fission products could be separated as a group from nuclear waste using plasma mass filters. Plasmabased processes are well suited to separating nuclear waste, because mass rather than chemical properties are used for separation. A single plasma stage can replace several stages of chemical separation, producing separate streams of bulk elements, fission products, and actinoids. The plasma mass filters may have lower cost and produce less auxiliary waste than chemical processing plants. Three rotating plasma configurations are considered that act as mass filters: the plasma centrifuge, the Ohkawa filter, and the asymmetric centrifugal trap.

Nuclear matter kinetic coefficients and damping of finite nuclear collective modes

International Nuclear Information System (INIS)

Toledo Piza, A.F.R. de.

1986-06-01

By carrying the general description of one-body observables beyond the mean-field approximation, those correlation terms responsible for Kinetic phenomena and those involved in the renormalization of the G-matrix mean-field in finite nuclei are identified. A Kinetic equation for the one-body density is obtained. Estimates for transport coefficients and for the damping of zero sound are obtained which point to the inadequacy of hydrodynamical descriptions of collective nuclear modes and indicate that collisional damping in large nuclei may account for one or a few tenths of the observed widths. (S.D.) [pt

New relativistic effective interaction for finite nuclei, infinite nuclear matter, and neutron stars

Science.gov (United States)

Kumar, Bharat; Patra, S. K.; Agrawal, B. K.

2018-04-01

We carry out the study of finite nuclei, infinite nuclear matter, and neutron star properties with the newly developed relativistic force, the Institute of Physics Bhubaneswar-I (IOPB-I). Using this force, we calculate the binding energies, charge radii, and neutron-skin thickness for some selected nuclei. From the ground-state properties of superheavy nuclei (Z =120 ), it is noticed that considerable shell gaps appear at neutron numbers N =172 , 184, and 198, manifesting the magicity at these numbers. The low-density behavior of the equation of state for pure neutron matter is compatible with other microscopic models. Along with the nuclear symmetry energy, its slope and curvature parameters at the saturation density are consistent with those extracted from various experimental data. We calculate the neutron star properties with the equation of state composed of nucleons and leptons in β -equilibrium, which are in good agreement with the x-ray observations by Steiner [Astrophys. J. 722, 33 (2010), 10.1088/0004-637X/722/1/33] and Nättilä [Astron. Astrophys. 591, A25 (2016), 10.1051/0004-6361/201527416]. Based on the recent observation of GW170817 with a quasi-universal relation, Rezzolla et al. [Astrophys. J. Lett. 852, L25 (2018), 10.3847/2041-8213/aaa401] have set a limit for the maximum mass that can be supported against gravity by a nonrotating neutron star in the range 2.01 ±0.04 ≲M (M⊙)≲2.16 ±0.03 . We find that the maximum mass of the neutron star for the IOPB-I parametrization is 2.15 M⊙ . The radius and tidal deformability of a canonical neutron star of mass 1.4 M⊙ are 13.2 km and 3.9 ×1036g cm2s2 , respectively.

Position-dependent mass, finite-gap systems, and supersymmetry

Science.gov (United States)

Bravo, Rafael; Plyushchay, Mikhail S.

2016-05-01

The ordering problem in quantum systems with position-dependent mass (PDM) is treated by inclusion of the classically fictitious similarity transformation into the kinetic term. This provides a generation of supersymmetry with the first-order supercharges from the kinetic term alone, while inclusion of the potential term allows us also to generate nonlinear supersymmetry with higher-order supercharges. A broad class of finite-gap systems with PDM is obtained by different reduction procedures, and general results on supersymmetry generation are applied to them. We show that elliptic finite-gap systems of Lamé and Darboux-Treibich-Verdier types can be obtained by reduction to Seiffert's spherical spiral and Bernoulli lemniscate in the presence of Calogero-like or harmonic oscillator potentials, or by angular momentum reduction of a free motion on some AdS2 -related surfaces in the presence of Aharonov-Bohm flux. The limiting cases include the Higgs and Mathews-Lakshmanan oscillator models as well as a reflectionless model with PDM exploited recently in the discussion of cosmological inflationary scenarios.

Compressibility, zero sound, and effective mass of a fermionic dipolar gas at finite temperature

International Nuclear Information System (INIS)

Kestner, J. P.; Das Sarma, S.

2010-01-01

The compressibility, zero-sound dispersion, and effective mass of a gas of fermionic dipolar molecules is calculated at finite temperature for one-, two-, and three-dimensional uniform systems, and in a multilayer quasi-two-dimensional system. The compressibility is nonmonotonic in the reduced temperature, T/T F , exhibiting a maximum at finite temperature. This effect might be visible in a quasi-low-dimensional experiment, providing a clear signature of the onset of many-body quantum degeneracy effects. The collective mode dispersion and effective mass show similar nontrivial temperature and density dependence. In a quasi-low-dimensional system, the zero-sound mode may propagate at experimentally attainable temperatures.

Realistic effective interactions for nuclear systems

International Nuclear Information System (INIS)

Hjort-Jensen, M.; Osnes, E.; Kuo, T.T.S.

1994-09-01

A review of perturbative many-body descriptions of several nuclear systems is presented. Symmetric and asymmetric nuclear matter and finite nuclei with few valence particles are examples of systems considered. The many-body description starts with the most recent meson-exchange potential models for the nucleon-nucleon interaction, an interaction which in turn is used in perturbative schemes to evaluate the effective interaction for finite nuclei and infinite nuclear matter. A unified perturbative approach based on time-dependent perturbation theory is elaborated. For finite nuclei new results are presented for the effective interaction and the energy spectra in the mass areas of oxygen, calcium and tin. 166 refs., 83 refs., 21 tabs

Interquark potential with finite quark mass from lattice QCD.

Science.gov (United States)

Kawanai, Taichi; Sasaki, Shoichi

2011-08-26

We present an investigation of the interquark potential determined from the q ̄q Bethe-Salpeter (BS) amplitude for heavy quarkonia in lattice QCD. The q ̄q potential at finite quark mass m(q) can be calculated from the equal-time and Coulomb gauge BS amplitude through the effective Schrödinger equation. The definition of the potential itself requires information about a kinetic mass of the quark. We then propose a self-consistent determination of the quark kinetic mass on the same footing. To verify the proposed method, we perform quenched lattice QCD simulations with a relativistic heavy-quark action at a lattice cutoff of 1/a≈2.1  GeV in a range 1.0≤m(q)≤3.6 GeV. Our numerical results show that the q ̄q potential in the m(q)→∞ limit is fairly consistent with the conventional one obtained from Wilson loops. The quark-mass dependence of the q ̄q potential and the spin-spin potential are also examined. © 2011 American Physical Society

Mass spectrometry in nuclear science and technology

International Nuclear Information System (INIS)

Komori, Takuji

1985-01-01

Mass spectrometry has been widely used and playing a very important role in the field of nuclear science and technology. A major reason for this is that not only the types of element but also its isotopes have to be identified and measured in this field. Thus, some applications of this analytical method are reviewed and discussed in this article. Its application to analytical chemistry is described in the second section following an introductory section, which includes subsections for isotropic dilution mass spectrometry, resonance ionization mass spectrometry and isotopic correlation technique. The isotopic ratio measurement for hydrogen, uranium and plutonium as well as nuclear material control and safeguards are also reviewed in this section. In the third section, mass spectrometry is discussed in relation to nuclear reactors, with subsections on natural uranium reactor and neutron flux observation. Some techniques for measuring the burnup fraction, including the heavy isotopic ratio method and fission product monitoring, are also described. In the fourth section, application of mass spectrometry to measurement of nuclear constants, such as ratio of effective cross-sectional area for 235 U, half-life and fission yield is reviewed. (Nogami, K.)

Mapping the N-Z plane: residual mass regularities

International Nuclear Information System (INIS)

Hirsch, J.G.; Frank, A.; Velazquez, V.

2004-01-01

A new development in the study of the deviations between experimental nuclear masses and those calculated in the framework of the Finite Range Droplet Model is introduced. Some frequencies are isolated and used in a simple fit to reduce significantly the error width. The presence of this regular residual correlations suggests that the Strutinsky method of including microscopic fluctuations in nuclear masses could be improved. (Author)

The Gogny-Hartree-Fock-Bogoliubov nuclear-mass model

Energy Technology Data Exchange (ETDEWEB)

Goriely, S. [Universite Libre de Bruxelles, Institut d' Astronomie et d' Astrophysique, CP-226, Brussels (Belgium); Hilaire, S.; Girod, M.; Peru, S. [CEA, DAM, DIF, Arpajon (France)

2016-07-15

We present the Gogny-Hartree-Fock-Bogoliubov model which reproduces nuclear masses with an accuracy comparable with the best mass formulas. In contrast to the Skyrme-HFB nuclear-mass models, an explicit and self-consistent account of all the quadrupole correlation energies is included within the 5D collective Hamiltonian approach. The final rms deviation with respect to the 2353 measured masses is 789 keV in the 2012 atomic mass evaluation. In addition, the D1M Gogny force is shown to predict nuclear and neutron matter properties in agreement with microscopic calculations based on realistic two- and three-body forces. The D1M properties and its predictions of various observables are compared with those of D1S and D1N. (orig.)

Systematics of nuclear mass and level density formulas

Energy Technology Data Exchange (ETDEWEB)

Nakamura, Hisashi [Fuji Electric Co. Ltd., Kawasaki, Kanagawa (Japan)

1998-03-01

The phenomenological models of the nuclear mass and level density are close related to each other, the nuclear ground and excited state properties are described by using the parameter systematics on the mass and level density formulas. The main aim of this work is to provide in an analytical framework the improved energy dependent shell, pairing and deformation corrections generalized to the collective enhancement factors, which offer a systematic prescription over a great number of nuclear reaction cross sections. The new formulas are shown to be in close agreement with not only the empirical nuclear mass data but the measured slow neutron resonance spacings, and experimental systematics observed in the excitation energy dependent properties. (author)

Testing the predictive power of nuclear mass models

International Nuclear Information System (INIS)

Mendoza-Temis, J.; Morales, I.; Barea, J.; Frank, A.; Hirsch, J.G.; Vieyra, J.C. Lopez; Van Isacker, P.; Velazquez, V.

2008-01-01

A number of tests are introduced which probe the ability of nuclear mass models to extrapolate. Three models are analyzed in detail: the liquid drop model, the liquid drop model plus empirical shell corrections and the Duflo-Zuker mass formula. If predicted nuclei are close to the fitted ones, average errors in predicted and fitted masses are similar. However, the challenge of predicting nuclear masses in a region stabilized by shell effects (e.g., the lead region) is far more difficult. The Duflo-Zuker mass formula emerges as a powerful predictive tool

Thermo field dynamics in the treatment of the nuclear pairing problem at finite temperature

International Nuclear Information System (INIS)

Civitarese, O.; DePaoli, A.L.

1993-01-01

The use of the thermo field dynamics, in dealing with the study of nuclear properties at finite temperature, is discussed for the case of a nuclear Hamiltonian which includes a single-particle term and a monopole pairing residual two-body interaction. The rules of the thermo fields dynamics are applied to double the Hilbert space, thus accounting for the thermal occupation of single-particle states, and to construct dual spaces, both for single-particle (BCS) and collective (RPA) degrees of freedom. It is shown that the rules of the thermo field dynamics yield to a temperature dependence of the equations describing quasiparticle and phonon excitations which is similar to the one found in the more conventional finite temperature Wick's theorem approach, namely: By dealing with thermal averages. (orig.)

Facing the challenge of nuclear mass tort processing

International Nuclear Information System (INIS)

Pelzer, Norbert

2017-01-01

A great majority of states do not issue any specific legislation on nuclear mass tort litigations. They apparently build on general traditional practice as most probably already tried and tested in other areas. Some states defer the decision on the way to deal with mass tort claims to the time of the nuclear incident. They insert into their nuclear liability laws respective 'reminders' that contain an invitation or a demand to the legislator to take appropriate steps if and when necessary. Finally, there are a number of states that enacted elaborate regimes on how to react to, and organise, compensation of mass damages after a catastrophic nuclear incident. Among those states are in particular major nuclear states like Canada, India, Japan and the US. They developed compensation schemes where claims for compensation of nuclear damage shall be dealt with by fora that are not regular courts. In some of those states, the fora are exclusively competent without a right to appeal their decisions, while in other states the fora act in parallel or in complement to courts. So the international scenario appears to be somewhat confusing. Of course, sovereign states are free to organise claims processing, including nuclear mass claims processing, as they deem fit. The discretion of states is, however, limited by obligations under public international law. With regard to the victims of nuclear incidents, states are particularly bound by obligations under the 1948 Universal Declaration of Human Rights and other relevant instruments they may be a party to. National nuclear mass claim processing has in particular to comply with the obligation to guarantee 'a fair and public hearing by an independent and impartial tribunal'. With regard to possible international obligations vis-a-vis other states, it has to be taken into account that major nuclear incidents, as a rule, have transboundary detrimental effects. There is always a potential impact on territories

User's manual for the FEHM application - A finite-element heat- and mass-transfer code

International Nuclear Information System (INIS)

Zyvoloski, G.A.; Robinson, B.A.; Dash, Z.V.; Trease, L.L.

1997-07-01

The use of this code is applicable to natural-state studies of geothermal systems and groundwater flow. A primary use of the FEHM application will be to assist in the understanding of flow fields and mass transport in the saturated and unsaturated zones below the proposed Yucca Mountain nuclear waste repository in Nevada. The equations of heat and mass transfer for multiphase flow in porous and permeable media are solved in the FEHM application by using the finite-element method. The permeability and porosity of the medium are allowed to depend on pressure and temperature. The code also has provisions for movable air and water phases and noncoupled tracers; that is, tracer solutions that do not affect the heat- and mass-transfer solutions. The tracers can be passive or reactive. The code can simulate two-dimensional, two-dimensional radial, or three-dimensional geometries. In fact, FEHM is capable of describing flow that is dominated in many areas by fracture and fault flow, including the inherently three-dimensional flow that results from permeation to and from faults and fractures. The code can handle coupled heat and mass-transfer effects, such as boiling, dryout, and condensation that can occur in the near-field region surrounding the potential repository and the natural convection that occurs through Yucca Mountain due to seasonal temperature changes. This report outlines the uses and capabilities of the FEHM application, initialization of code variables, restart procedures, and error processing. The report describes all the data files, the input data, including individual input records or parameters, and the various output files. The system interface is described, including the software environment and installation instructions

Validating neural-network refinements of nuclear mass models

Science.gov (United States)

Utama, R.; Piekarewicz, J.

2018-01-01

Background: Nuclear astrophysics centers on the role of nuclear physics in the cosmos. In particular, nuclear masses at the limits of stability are critical in the development of stellar structure and the origin of the elements. Purpose: We aim to test and validate the predictions of recently refined nuclear mass models against the newly published AME2016 compilation. Methods: The basic paradigm underlining the recently refined nuclear mass models is based on existing state-of-the-art models that are subsequently refined through the training of an artificial neural network. Bayesian inference is used to determine the parameters of the neural network so that statistical uncertainties are provided for all model predictions. Results: We observe a significant improvement in the Bayesian neural network (BNN) predictions relative to the corresponding "bare" models when compared to the nearly 50 new masses reported in the AME2016 compilation. Further, AME2016 estimates for the handful of impactful isotopes in the determination of r -process abundances are found to be in fairly good agreement with our theoretical predictions. Indeed, the BNN-improved Duflo-Zuker model predicts a root-mean-square deviation relative to experiment of σrms≃400 keV. Conclusions: Given the excellent performance of the BNN refinement in confronting the recently published AME2016 compilation, we are confident of its critical role in our quest for mass models of the highest quality. Moreover, as uncertainty quantification is at the core of the BNN approach, the improved mass models are in a unique position to identify those nuclei that will have the strongest impact in resolving some of the outstanding questions in nuclear astrophysics.

Effective masses and the nuclear mean field

International Nuclear Information System (INIS)

Mahaux, C.; Sartor, R.

1985-01-01

The effective mass characterizes the energy dependence of the empirical average nuclear potential. This energy dependence has two different sources, namely the nonlocality in space of the microscopic mean field on the one hand, and its true energy dependence on the other hand. Correspondingly it is convenient to divide the effective mass into two components, the k-mass and the ω-mass. The latter is responsible for the existence of a peak in the energy dependence of the effective mass. This peak is located near the Fermi energy in nuclear matter and in nuclei, as well as in the electron gas, the hard sphere Fermi gas and liquid helium 3. A related phenomenon is the existence of a low energy anomaly in the energy dependence of the optical model potential between two heavy ions. (orig.)

Higgs, Top, and Bottom Mass Predictions in Finite Unified Theories

CERN Document Server

Heinemeyer, Sven; Zoupanos, George

2014-01-01

All-loop Finite Unified Theories (FUTs) are N = 1 supersymmetric Grand Unified Theories (GUTs) based on the principle of reduction of couplings, which have a remarkable predictive power. The reduction of couplings implies the existence of renormalization group invariant relations among them, which guarantee the vanishing of the beta functions at all orders in perturbation theory in particular N = 1 GUTs. In the soft breaking sector these relations imply the existence of a sum rule among the soft scalar masses. The confrontation of the predictions of a SU(5) FUT model with the top and bottom quark masses and other low-energy experimental constraints leads to a prediction of the light Higgs-boson mass in the rangeMh ∼ 121−126 GeV, in remarkable agreement with the discovery of the Higgs boson with a mass around ∼ 125.7 GeV. Also a relatively heavy spectrum with coloured supersymmetric particles above ∼ 1.5 TeV is predicted, consistent with the non-observation of those particles at the LHC.

Polyakov loop and spin correlators on finite lattices. A study beyond the mass gap

International Nuclear Information System (INIS)

Engels, J.; Neuhaus, T.

1995-01-01

We derive an analytic expression for point-to-point correlation functions of the Polyakov loop based on the transfer matrix formalism. For the 2D Ising model we show that the results deduced from point-point spin correlators are coinciding with those from zero momentum correlators. We investigate the contributions from eigenvalues of the transfer matrix beyond the mass gap and discuss the limitations and possibilities of such an analysis. The finite size behaviour of the obtained 2D Ising model matrix elements is examined. The point-to-point correlator formula is then applied to Polyakov loop data in finite temperature SU(2) gauge theory. The leading matrix element shows all expected scaling properties. Just above the critical point we find a Debye screening mass μ D /T∼4, independent of the volume. ((orig.))

Finite element analysis of an inflatable torus considering air mass structural element

Science.gov (United States)

Gajbhiye, S. C.; Upadhyay, S. H.; Harsha, S. P.

2014-01-01

Inflatable structures, also known as gossamer structures, are at high boom in the current space technology due to their low mass and compact size comparing to the traditional spacecraft designing. Internal pressure becomes the major source of strength and rigidity, essentially stiffen the structure. However, inflatable space based membrane structure are at high risk to the vibration disturbance due to their low structural stiffness and material damping. Hence, the vibration modes of the structure should be known to a high degree of accuracy in order to provide better control authority. In the past, most of the studies conducted on the vibration analysis of gossamer structures used inaccurate or approximate theories in modeling the internal pressure. The toroidal shaped structure is one of the important key element in space application, helps to support the reflector in space application. This paper discusses the finite-element analysis of an inflated torus. The eigen-frequencies are obtained via three-dimensional small-strain elasticity theory, based on extremum energy principle. The two finite-element model (model-1 and model-2) have cases have been generated using a commercial finite-element package. The structure model-1 with shell element and model-2 with the combination of the mass of enclosed fluid (air) added to the shell elements have been taken for the study. The model-1 is computed with present analytical approach to understand the convergence rate and the accuracy. The convergence study is made available for the symmetric modes and anti-symmetric modes about the centroidal-axis plane, meeting the eigen-frequencies of an inflatable torus with the circular cross section. The structural model-2 is introduced with air mass element and analyzed its eigen-frequency with different aspect ratio and mode shape response using in-plane and out-plane loading condition are studied.

Finiteness preserving mass terms in N=4 super Yang-Mills theory

International Nuclear Information System (INIS)

Rajpoot, S.; Taylor, J.G.; Zaimi, M.

1983-01-01

It is shown using light cone gauge techniques that N = 4 super Yang-Mills theory is ultraviolet finite in the presence of a wide range of explicit symmetry breaking mass terms for (a) scalars and fermions (b) scalars alone. These mass terms satisfy sum rules that are part of the more general sum rule: μsub(s=0,) sub(1/2) (-1)sup(2S+1)(2s + 1)msub(S) 2 = 0, in which the mass of vector bosons is set to zero for reasons of gauge invariance. The resulting lagrangians offer the exciting possibility of realising explicit hierarchical descent of N = 4 super Yang-Mills through N = 2 and N = 1 supersymmetries. Tree level spontaneous symmetry breaking from the resulting scalar potentials are briefly discussed. (orig.)

Masses of exotic calcium isotopes pin down nuclear forces

CERN Document Server

Wienholtz, F; Blaum, K; Borgmann, Ch; Breitenfeldt, M; Cakirli, R B; George, S; Herfurth, F; Holt, J D; Kowalska, M; Kreim, S; Lunney, D; Manea, V; Menéndez, J; Neidherr, D; Rosenbusch, M; Schweikhard, L; Schwenk, A; Simonis, J; Stanja, J; Wolf, R N; Zuber, K

2013-01-01

The properties of exotic nuclei on the verge of existence play a fundamental part in our understanding of nuclear interactions. Exceedingly neutron-rich nuclei become sensitive to new aspects of nuclear forces. Calcium, with its doubly magic isotopes $^{40}$Ca and $^{48}$Ca, is an ideal test for nuclear shell evolution, from the valley of stability to the limits of existence. With a closed proton shell, the calcium isotopes mark the frontier for calculations with three-nucleon forces from chiral effective field theory. Whereas predictions for the masses of $^{51}$Ca and $^{52}$Ca have been validated by direct measurements$^4$, it is an open question as to how nuclear masses evolve for heavier calcium isotopes. Here we report the mass determination of the exotic calcium isotopes $^{53}$Ca and $^{54}$Ca, using the multi-reflection time-of-flight mass spectrometer of ISOLTRAP at CERN. The measured masses unambiguously establish a prominent shell closure at neutron number N = 32, in excellent agreement with our t...

Analysis on one underground nuclear waste repository rock mass in USA

International Nuclear Information System (INIS)

Ha Qiuling; Zhang Tiantian

2012-01-01

When analyzing the rock mass of a underground nuclear waste repository, the current studies are all based on the loading mechanical condition, and the unloading damage of rock mass is unconsidered. According to the different mechanical condition of actual engineering rock mass of loading and unloading, this paper implements a comprehensive analysis on the rock mass deformation of underground nuclear waste repository through the combination of present loading and unloading rock mass mechanics. It is found that the results of comprehensive analysis and actual measured data on the rock mass deformation of underground nuclear waste repository are basically the same, which provide supporting data for the underground nuclear waste repository. (authors)

User's Manual for the FEHM Application-A Finite-Element Heat- and Mass-Transfer Code

Energy Technology Data Exchange (ETDEWEB)

George A. Zyvoloski; Bruce A. Robinson; Zora V. Dash; Lynn L. Trease

1997-07-07

This document is a manual for the use of the FEHM application, a finite-element heat- and mass-transfer computer code that can simulate nonisothermal multiphase multicomponent flow in porous media. The use of this code is applicable to natural-state studies of geothermal systems and groundwater flow. A primary use of the FEHM application will be to assist in the understanding of flow fields and mass transport in the saturated and unsaturated zones below the proposed Yucca Mountain nuclear waste repository in Nevada. The equations of heat and mass transfer for multiphase flow in porous and permeable media are solved in the FEHM application by using the finite-element method. The permeability and porosity of the medium are allowed to depend on pressure and temperature. The code also has provisions for movable air and water phases and noncoupled tracers; that is, tracer solutions that do not affect the heat- and mass-transfer solutions. The tracers can be passive or reactive. The code can simulate two-dimensional, two-dimensional radial, or three-dimensional geometries. In fact, FEHM is capable of describing flow that is dominated in many areas by fracture and fault flow, including the inherently three-dimensional flow that results from permeation to and from faults and fractures. The code can handle coupled heat and mass-transfer effects, such as boiling, dryout, and condensation that can occur in the near-field region surrounding the potential repository and the natural convection that occurs through Yucca Mountain due to seasonal temperature changes. The code is also capable of incorporating the various adsorption mechanisms, ranging from simple linear relations to nonlinear isotherms, needed to describe the very complex transport processes at Yucca Mountain. This report outlines the uses and capabilities of the FEHM application, initialization of code variables, restart procedures, and error processing. The report describes all the data files, the input data

Solution of the Lambda modes problem of a nuclear power reactor using an h–p finite element method

International Nuclear Information System (INIS)

Vidal-Ferrandiz, A.; Fayez, R.; Ginestar, D.; Verdú, G.

2014-01-01

Highlights: • An hp finite element method is proposed for the Lambda modes problem of a nuclear reactor. • Different strategies can be implemented for increasing the accuracy of the solutions. • 2D and 3D benchmarks have been studied obtaining accurate results. - Abstract: Lambda modes of a nuclear power reactor have interest in reactor physics since they have been used to develop modal methods and to study BWR reactor instabilities. An h–p-Adaptation finite element method has been implemented to compute the dominant modes the fundamental mode and the next subcritical modes of a nuclear reactor. The performance of this method has been studied in three benchmark problems, a homogeneous 2D reactor, the 2D BIBLIS reactor and the 3D IAEA reactor

User`s manual for the FEHM application -- A finite-element heat- and mass-transfer code

Energy Technology Data Exchange (ETDEWEB)

Zyvoloski, G.A.; Robinson, B.A.; Dash, Z.V.; Trease, L.L.

1997-07-01

The use of this code is applicable to natural-state studies of geothermal systems and groundwater flow. A primary use of the FEHM application will be to assist in the understanding of flow fields and mass transport in the saturated and unsaturated zones below the proposed Yucca Mountain nuclear waste repository in Nevada. The equations of heat and mass transfer for multiphase flow in porous and permeable media are solved in the FEHM application by using the finite-element method. The permeability and porosity of the medium are allowed to depend on pressure and temperature. The code also has provisions for movable air and water phases and noncoupled tracers; that is, tracer solutions that do not affect the heat- and mass-transfer solutions. The tracers can be passive or reactive. The code can simulate two-dimensional, two-dimensional radial, or three-dimensional geometries. In fact, FEHM is capable of describing flow that is dominated in many areas by fracture and fault flow, including the inherently three-dimensional flow that results from permeation to and from faults and fractures. The code can handle coupled heat and mass-transfer effects, such as boiling, dryout, and condensation that can occur in the near-field region surrounding the potential repository and the natural convection that occurs through Yucca Mountain due to seasonal temperature changes. This report outlines the uses and capabilities of the FEHM application, initialization of code variables, restart procedures, and error processing. The report describes all the data files, the input data, including individual input records or parameters, and the various output files. The system interface is described, including the software environment and installation instructions.

Dependence of X-Ray Burst Models on Nuclear Masses

Energy Technology Data Exchange (ETDEWEB)

Schatz, H.; Ong, W.-J. [National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, MI 48824 (United States)

2017-08-01

X-ray burst model predictions of light curves and the final composition of the nuclear ashes are affected by uncertain nuclear masses. However, not all of these masses are determined experimentally with sufficient accuracy. Here we identify the remaining nuclear mass uncertainties in X-ray burst models using a one-zone model that takes into account the changes in temperature and density evolution caused by changes in the nuclear physics. Two types of bursts are investigated—a typical mixed H/He burst with a limited rapid proton capture process (rp-process) and an extreme mixed H/He burst with an extended rp-process. When allowing for a 3 σ variation, only three remaining nuclear mass uncertainties affect the light-curve predictions of a typical H/He burst ({sup 27}P, {sup 61}Ga, and {sup 65}As), and only three additional masses affect the composition strongly ({sup 80}Zr, {sup 81}Zr, and {sup 82}Nb). A larger number of mass uncertainties remain to be addressed for the extreme H/He burst, with the most important being {sup 58}Zn, {sup 61}Ga, {sup 62}Ge, {sup 65}As, {sup 66}Se, {sup 78}Y, {sup 79}Y, {sup 79}Zr, {sup 80}Zr, {sup 81}Zr, {sup 82}Zr, {sup 82}Nb, {sup 83}Nb, {sup 86}Tc, {sup 91}Rh, {sup 95}Ag, {sup 98}Cd, {sup 99}In, {sup 100}In, and {sup 101}In. The smallest mass uncertainty that still impacts composition significantly when varied by 3 σ is {sup 85}Mo with 16 keV uncertainty. For one of the identified masses, {sup 27}P, we use the isobaric mass multiplet equation to improve the mass uncertainty, obtaining an atomic mass excess of −716(7) keV. The results provide a roadmap for future experiments at advanced rare isotope beam facilities, where all the identified nuclides are expected to be within reach for precision mass measurements.

Application of finite element numerical technique to nuclear reactor geometries

Energy Technology Data Exchange (ETDEWEB)

Rouai, N M [Nuclear engineering department faculty of engineering Al-fateh universty, Tripoli (Libyan Arab Jamahiriya)

1995-10-01

Determination of the temperature distribution in nuclear elements is of utmost importance to ensure that the temperature stays within safe limits during reactor operation. This paper discusses the use of Finite element numerical technique (FE) for the solution of the two dimensional heat conduction equation in geometries related to nuclear reactor cores. The FE solution stats with variational calculus which considers transforming the heat conduction equation into an integral equation I(O) and seeks a function that minimizes this integral and hence gives the solution to the heat conduction equation. In this paper FE theory as applied to heat conduction is briefly outlined and a 2-D program is used to apply the theory to simple shapes and to two gas cooled reactor fuel elements. Good results are obtained for both cases with reasonable number of elements. 7 figs.

Application of finite element numerical technique to nuclear reactor geometries

International Nuclear Information System (INIS)

Rouai, N. M.

1995-01-01

Determination of the temperature distribution in nuclear elements is of utmost importance to ensure that the temperature stays within safe limits during reactor operation. This paper discusses the use of Finite element numerical technique (FE) for the solution of the two dimensional heat conduction equation in geometries related to nuclear reactor cores. The FE solution stats with variational calculus which considers transforming the heat conduction equation into an integral equation I(O) and seeks a function that minimizes this integral and hence gives the solution to the heat conduction equation. In this paper FE theory as applied to heat conduction is briefly outlined and a 2-D program is used to apply the theory to simple shapes and to two gas cooled reactor fuel elements. Good results are obtained for both cases with reasonable number of elements. 7 figs

Impact of Precision Mass Measurements on Nuclear Physics and Astrophysics

CERN Document Server

Kreim, Susanne; Dilling, Jens; Litvinov, Yuri A

2013-01-01

Among all nuclear ground-state properties, atomic masses are highly specific for each particular combination of neutron and proton number, N and Z, respectively. The data obtained through mass measurements provide details of the nuclear interaction and thus apply to a variety of physics topics. Some of the most crucial questions to be addressed by mass spectrometry of unstable radionuclides are, on the one hand, nuclear forces and structure, describing phenomena such as the so-called neutron-halos or the evolution of magic numbers when moving towards the borders of nuclear existence. On the other hand, the understanding of the processes of element formation in the Universe poses a challenge and requires an accurate knowledge of nuclear astrophysics. Here, precision atomic mass values of a large number of exotic nuclei participating in nucleosynthesis processes are among the key input data in large-scale reaction network calculations.

Finite temperature corrections to tachyon mass in intersecting D-branes

International Nuclear Information System (INIS)

Sethi, Varun; Chowdhury, Sudipto Paul; Sarkar, Swarnendu

2017-01-01

We continue with the analysis of finite temperature corrections to the Tachyon mass in intersecting branes which was initiated in https://www.doi.org/10.1007/JHEP09(2014)063. In this paper we extend the computation to the case of intersecting D3 branes by considering a setup of two intersecting branes in flat-space background. A holographic model dual to BCS superconductor consisting of intersecting D8 branes in D4 brane background was proposed in https://www.doi.org/10.1016/j.nuclphysb.2011.07.011. The background considered here is a simplified configuration of this dual model. We compute the one-loop Tachyon amplitude in the Yang-Mills approximation and show that the result is finite. Analyzing the amplitudes further we numerically compute the transition temperature at which the Tachyon becomes massless. The analytic expressions for the one-loop amplitudes obtained here reduce to those for intersecting D1 branes obtained in https://www.doi.org/10.1007/JHEP09(2014)063 as well as those for intersecting D2 branes.

Finite temperature corrections to tachyon mass in intersecting D-branes

Energy Technology Data Exchange (ETDEWEB)

Sethi, Varun [Department of Physics and Astrophysics, University of Delhi,Delhi 110007 (India); Chowdhury, Sudipto Paul [Institute of Physics, Sachivalaya Marg,Bhubaneswar 751005 (India); Sarkar, Swarnendu [Department of Physics and Astrophysics, University of Delhi,Delhi 110007 (India)

2017-04-19

We continue with the analysis of finite temperature corrections to the Tachyon mass in intersecting branes which was initiated in https://www.doi.org/10.1007/JHEP09(2014)063. In this paper we extend the computation to the case of intersecting D3 branes by considering a setup of two intersecting branes in flat-space background. A holographic model dual to BCS superconductor consisting of intersecting D8 branes in D4 brane background was proposed in https://www.doi.org/10.1016/j.nuclphysb.2011.07.011. The background considered here is a simplified configuration of this dual model. We compute the one-loop Tachyon amplitude in the Yang-Mills approximation and show that the result is finite. Analyzing the amplitudes further we numerically compute the transition temperature at which the Tachyon becomes massless. The analytic expressions for the one-loop amplitudes obtained here reduce to those for intersecting D1 branes obtained in https://www.doi.org/10.1007/JHEP09(2014)063 as well as those for intersecting D2 branes.

Pionic atom as a probe of origin of the Hadron Mass. Quantitative evaluation of the chiral condensate in a nuclear medium

International Nuclear Information System (INIS)

Suzuki, Ken; Itahashi, Kenta; Hirenzaki, Satoru

2005-01-01

Spontaneous breaking of chiral symmetry is believed to be the mechanism which endows nucleus their large masses. The order parameter of the symmetry breaking is the chiral condensate, whose magnitude is predicted to decrease linearly as the nuclear density is increased. The reduction of quark condensate was quantitatively studied from recent precise measurement of deeply bound pionic 1s states on three tin (Sn) isotopes. We made use of the Gell-Mann-Oakes-Renner relation which connects the magnitude of quark-codensate to a pion decay constant, and then used the Tomozawa-Weinberg relation which relates the pion decay constant to an isovector strength of the pion-nucleus potential. The potential strength was determined by fitting the measured pionic 1s-state binding energies. The result shows that the quark-condensate strength is reduced by about 35% at normal nuclear density, compared with the ''vacuum'' value obtained from pionic hydrogen X-ray measurements. This is the first quantitative deduction of the quark condensate modification at finite nuclear density, and is an important step towards understanding the origin of hadron masses. (author)

Equations of the quasiparticle-phonon nuclear model with effective finite-rank separable interactions

International Nuclear Information System (INIS)

Solov'ev, V.G.

1989-01-01

Basic equations are derived for the quasiparticle-phonon nuclear model for the finite-rank separable isoscalar and isovector multipole and spin-multipole and isovector tensor particle-hole and particle-particle interactions between quasiparticles. For even-even spherical nuclei it is shown that in the calculation of single-phonon states in the random phase approximation a significant complication arises due to the finite rank n max >1 of separable interactions. Taking into account separable interactions with n max >1 does not lead to significant difficulties in the calculation of fragmentation of quasiparticle and collective states. It is asserted that the model can be used as a basis for calculations of many characteristics of complex nuclei

Finite element simulations of two rock mechanics tests

International Nuclear Information System (INIS)

Dahlke, H.J.; Lott, S.A.

1986-04-01

Rock mechanics tests are performed to determine in situ stress conditions and material properties of an underground rock mass. To design stable underground facilities for the permanent storage of high-level nuclear waste, determination of these properties and conditions is a necessary first step. However, before a test and its associated equipment can be designed, the engineer needs to know the range of expected values to be measured by the instruments. Sensitivity studies by means of finite element simulations are employed in this preliminary design phase to evaluate the pertinent parameters and their effects on the proposed measurements. The simulations, of two typical rock mechanics tests, the plate bearing test and the flat-jack test, by means of the finite element analysis, are described. The plate bearing test is used to determine the rock mass deformation modulus. The flat-jack test is used to determine the in situ stress conditions of the host rock. For the plate bearing test, two finite element models are used to simulate the classic problem of a load on an elastic half space and the actual problem of a plate bearing test in an underground tunnel of circular cross section. For the flat-jack simulation, a single finite element model is used to simulate both horizontal and vertical slots. Results will be compared to closed-form solutions available in the literature

Extending and refining the nuclear mass surface with ISOLTRAP and MISTRAL

CERN Document Server

Lunney, M D

2000-01-01

Through the nuclear binding energy the atomic mass gives us important information about nuclear structure. Viewing the ensemble of mass data over the nuclear chart, we can examine the hills and valleys that form this surface and make hypotheses about the effects of certain nuclear configurations. To unveil these effects, mass measurements of very high precision (10$^{-6}$) are required. Two experiments at ISOLDE pursue this effort of nuclear cartography the tandem Penning trap spectrometer ISOLTRAP and the radiofrequency transmission spectrometer MISTRAL. Between them, the masses of almost 150 nuclides have been measured from stable isotopes to those with half-lives as short as 30 ms. Both experiments rely on good optical properties of a low energy ion beam and are thus well suited to the ISOLDE facility. (30 refs).

Infinite nuclear matter model and mass formulae for nuclei

International Nuclear Information System (INIS)

Satpathy, L.

2016-01-01

The matter composed of the nucleus is a quantum-mechanical interacting many-fermionic system. However, the shell and classical liquid drop have been taken as the two main features of nuclear dynamics, which have guided the evolution of nuclear physics. These two features can be considered as the macroscopic manifestation of the microscopic dynamics of the nucleons at fundamental level. Various mass formulae have been developed based on either of these features over the years, resulting in many ambiguities and uncertainties posing many challenges in this field. Keeping this in view, Infinite Nuclear Matter (INM) model has been developed during last couple of decades with a many-body theoretical foundation employing the celebrated Hugenholtz-Van Hove theorem, quite appropriate for the interacting quantum-mechanical nuclear system. A mass formula called INM mass formula based on this model yields rms deviation of 342 keV being the lowest in literature. Some of the highlights of its result includes its determination of INM density in agreement with the electron scattering data leading to the resolution of the long standing 'r 0 -paradox' it predicts new magic numbers giving rise to new island of stability in the drip-line regions. This is the manifestation of a new phenomenon where shell-effect over comes the repulsive component of nucleon-nucleon force resulting in the broadening of the stability peninsula. Shell quenching in N= 82,and N= 126 shells, and several islands of inversion have been predicted. The model determines the empirical value of the nuclear compression modulus, using high precission 4500 data comprising nuclear masses, neutron and proton separation energies. The talk will give a critical review of the field of mass formula and our understanding of nuclear dynamics as a whole

Summary of the models and methods for the FEHM application - a finite-element heat- and mass-transfer code

International Nuclear Information System (INIS)

Zyvoloski, G.A.; Robinson, B.A.; Dash, Z.V.; Trease, L.L.

1997-07-01

The mathematical models and numerical methods employed by the FEHM application, a finite-element heat- and mass-transfer computer code that can simulate nonisothermal multiphase multi-component flow in porous media, are described. The use of this code is applicable to natural-state studies of geothermal systems and groundwater flow. A primary use of the FEHM application will be to assist in the understanding of flow fields and mass transport in the saturated and unsaturated zones below the proposed Yucca Mountain nuclear waste repository in Nevada. The component models of FEHM are discussed. The first major component, Flow- and Energy-Transport Equations, deals with heat conduction; heat and mass transfer with pressure- and temperature-dependent properties, relative permeabilities and capillary pressures; isothermal air-water transport; and heat and mass transfer with noncondensible gas. The second component, Dual-Porosity and Double-Porosity/Double-Permeability Formulation, is designed for problems dominated by fracture flow. Another component, The Solute-Transport Models, includes both a reactive-transport model that simulates transport of multiple solutes with chemical reaction and a particle-tracking model. Finally, the component, Constitutive Relationships, deals with pressure- and temperature-dependent fluid/air/gas properties, relative permeabilities and capillary pressures, stress dependencies, and reactive and sorbing solutes. Each of these components is discussed in detail, including purpose, assumptions and limitations, derivation, applications, numerical method type, derivation of numerical model, location in the FEHM code flow, numerical stability and accuracy, and alternative approaches to modeling the component

Nuclear dynamics with the (finite range) Gogny force: flow effects

International Nuclear Information System (INIS)

Sebille, F.; Royer, G.; Schuck, P.; Gregoire, C.

1988-01-01

We introduce for the first time the effective finite range interaction of Gogny in the semi-classical description of heavy ion reactions based on the Landau-Vlasov equation. The characteristics of the flow for heavy ion collisions are studied as functions of the incident energy, the impact parameter and the mass number. The momentum dependence in the mean field together with the non linearities in the collision kernel decrease the flow in contradiction with other calculations; the origins of this discrepancy are studied in details

Finite size and Coulomb corrections: from nuclei to nuclear liquid vapor phase diagram

International Nuclear Information System (INIS)

Moretto, L.G.; Elliott, J.B.; Phair, L.

2003-01-01

In this paper we consider the problem of obtaining the infinite symmetric uncharged nuclear matter phase diagram from a thermal nuclear reaction. In the first part we shall consider the Coulomb interaction which, because of its long range makes the definition of phases problematic. This Coulomb effect seems truly devastating since it does not allow one to define nuclear phase transitions much above A ∼ 30. However there may be a solution to this difficulty. If we consider the emission of particles with a sizable charge, we notice that a large Coulomb barrier Bc is present. For T << Bc these channels may be considered effectively closed. Consequently the unbound channels may not play a role on a suitably short time scale. Then a phase transition may still be definable in an approximate way. In the second part of the article we shall deal with the finite size problem by means of a new method, the complement method, which shall permit a straightforward extrapolation to the infinite system. The complement approach consists of evaluating the change in free energy occurring when a particle or cluster is moved from one (finite) phase to another. In the case of a liquid drop in equilibrium with its vapor, this is done by extracting a vapor particle of any given size from the drop and evaluating the energy and entropy changes associated with both the vapor particle and the residual liquid drop (complement)

On finite volume effects in the chiral extrapolation of baryon masses

CERN Document Server

Lutz, M F M; Kobdaj, C; Schwarz, K

2014-01-01

We perform an analysis of the QCD lattice data on the baryon octet and decuplet masses based on the relativistic chiral Lagrangian. The baryon self energies are computed in a finite volume at next-to-next-to-next-to leading order (N^3LO), where the dependence on the physical meson and baryon masses is kept. The number of free parameters is reduced significantly down to 12 by relying on large-N_c sum rules. Altogether we describe accurately more than 220 data points from six different lattice groups, BMW, PACS-CS, HSC, LHPC, QCDSF-UKQCD and NPLQCD. Precise values for all counter terms relevant at N^3LO are predicted. In particular we extract a pion-nucleon sigma term of (39 +- 1) MeV and a strangeness sigma term of the nucleon of sigma_{sN} simeq (4 +- 1) MeV. The flavour SU(3) chiral limit of the baryon octet and decuplet masses is determined with ( 802 +- 4 ) MeV and (1103 +- 6) MeV. Detailed predictions for the baryon masses as currently evaluated by the ETM lattice QCD group are made.

The low-energy effective theory of QCD at small quark masses in a finite volume

Energy Technology Data Exchange (ETDEWEB)

Lehner, Christoph

2010-01-15

At low energies the theory of quantum chromodynamics (QCD) can be described effectively in terms of the lightest particles of the theory, the pions. This approximation is valid for temperatures well below the mass difference of the pions to the next heavier particles. We study the low-energy effective theory at very small quark masses in a finite volume V. The corresponding perturbative expansion in 1/{radical}(V) is called {epsilon} expansion. At each order of this expansion a finite number of low-energy constants completely determine the effective theory. These low-energy constants are of great phenomenological importance. In the leading order of the {epsilon} expansion, called {epsilon} regime, the theory becomes zero-dimensional and is therefore described by random matrix theory (RMT). The dimensionless quantities of RMT are mapped to dimensionful quantities of the low-energy effective theory using the leading-order lowenergy constants {sigma} and F. In this way {sigma} and F can be obtained from lattice QCD simulations in the '' regime by a fit to RMT predictions. For typical volumes of state-of-the-art lattice QCD simulations, finite-volume corrections to the RMT prediction cannot be neglected. These corrections can be calculated in higher orders of the {epsilon} expansion. We calculate the finite-volume corrections to {sigma} and F at next-to-next-to-leading order in the {epsilon} expansion. We also discuss non-universal modifications of the theory due to the finite volume. These results are then applied to lattice QCD simulations, and we extract {sigma} and F from eigenvalue correlation functions of the Dirac operator. As a side result, we provide a proof of equivalence between the parametrization of the partially quenched low-energy effective theory without singlet particle and that of the super-Riemannian manifold used earlier in the literature. Furthermore, we calculate a special version of the massless sunset diagram at finite volume without

Liquid-gas phase transition in asymmetric nuclear matter at finite temperature

Science.gov (United States)

Maruyama, Toshiki; Tatsumi, Toshitaka; Chiba, Satoshi

2010-03-01

Liquid-gas phase transition is discussed in warm asymmetric nuclear matter. Some peculiar features are figured out from the viewpoint of the basic thermodynamics about the phase equilibrium. We treat the mixed phase of the binary system based on the Gibbs conditions. When the Coulomb interaction is included, the mixed phase is no more uniform and the sequence of the pasta structures appears. Comparing the results with those given by the simple bulk calculation without the Coulomb interaction, we extract specific features of the pasta structures at finite temperature.

Liquid-gas phase transition in asymmetric nuclear matter at finite temperature

International Nuclear Information System (INIS)

Maruyama, Toshiki; Tatsumi, Toshitaka; Chiba, Satoshi

2010-01-01

Liquid-gas phase transition is discussed in warm asymmetric nuclear matter. Some peculiar features are figured out from the viewpoint of the basic thermodynamics about the phase equilibrium. We treat the mixed phase of the binary system based on the Gibbs conditions. When the Coulomb interaction is included, the mixed phase is no more uniform and the sequence of the pasta structures appears. Comparing the results with those given by the simple bulk calculation without the Coulomb interaction, we extract specific features of the pasta structures at finite temperature.

Quark-Meson-Coupling (QMC) model for finite nuclei, nuclear matter and beyond

Science.gov (United States)

Guichon, P. A. M.; Stone, J. R.; Thomas, A. W.

2018-05-01

The Quark-Meson-Coupling model, which self-consistently relates the dynamics of the internal quark structure of a hadron to the relativistic mean fields arising in nuclear matter, provides a natural explanation to many open questions in low energy nuclear physics, including the origin of many-body nuclear forces and their saturation, the spin-orbit interaction and properties of hadronic matter at a wide range of densities up to those occurring in the cores of neutron stars. Here we focus on four aspects of the model (i) a full comprehensive survey of the theory, including the latest developments, (ii) extensive application of the model to ground state properties of finite nuclei and hypernuclei, with a discussion of similarities and differences between the QMC and Skyrme energy density functionals, (iii) equilibrium conditions and composition of hadronic matter in cold and warm neutron stars and their comparison with the outcome of relativistic mean-field theories and, (iv) tests of the fundamental idea that hadron structure changes in-medium.

Valuing modular nuclear power plants in finite time decision horizon

International Nuclear Information System (INIS)

Jain, Shashi; Roelofs, Ferry; Oosterlee, Cornelis W.

2013-01-01

Small and medium sized reactors, SMRs, (according to IAEA, ‘small’ refers to reactors with power less than 300 MWe, and ‘medium’ with power less than 700 MWe) are considered as an attractive option for investment in nuclear power plants. SMRs may benefit from flexibility of investment, reduced upfront expenditure, enhanced safety, and easy integration with small sized grids. Large reactors on the other hand have been an attractive option due to the economy of scale. In this paper we focus on the economic impact of flexibility due to modular construction of SMRs. We demonstrate, using real option analysis, the value of sequential modular SMRs. Numerical results under different considerations of decision time, uncertainty in electricity prices, and constraints on the construction of units, are reported for a single large unit and for modular SMRs. - Highlights: ► Real option value of modular construction in finite time decision horizon. ► Stochastic grid method is used to value the real option. ► Decisions in finite time can differ significantly from infinite decision time. ► Decisions depend on length of decision horizon and price volatilities

Mass spectrometric analysis for nuclear safeguards

OpenAIRE

BOULYGA S.; KONEGGER-KAPPEL S.; RICHTER Stephan; SANGELY L.

2014-01-01

Mass spectrometry is currently being implemented in a wide spectrum of research and industrial areas, such as material sciences, cosmo- and geochemistry, biology and medicine, to name just a few. Research and development in nuclear safeguards is closely related to the general field of “Peace Research”; representing a specific application area for analytical sciences in general and for mass spectrometry in particular. According to Albert Einstein “peace cannot be kept by force. It only can be ...

Finite difference applied to the reconstruction method of the nuclear power density distribution

International Nuclear Information System (INIS)

Pessoa, Paulo O.; Silva, Fernando C.; Martinez, Aquilino S.

2016-01-01

Highlights: • A method for reconstruction of the power density distribution is presented. • The method uses discretization by finite differences of 2D neutrons diffusion equation. • The discretization is performed homogeneous meshes with dimensions of a fuel cell. • The discretization is combined with flux distributions on the four node surfaces. • The maximum errors in reconstruction occur in the peripheral water region. - Abstract: In this reconstruction method the two-dimensional (2D) neutron diffusion equation is discretized by finite differences, employed to two energy groups (2G) and meshes with fuel-pin cell dimensions. The Nodal Expansion Method (NEM) makes use of surface discontinuity factors of the node and provides for reconstruction method the effective multiplication factor of the problem and the four surface average fluxes in homogeneous nodes with size of a fuel assembly (FA). The reconstruction process combines the discretized 2D diffusion equation by finite differences with fluxes distribution on four surfaces of the nodes. These distributions are obtained for each surfaces from a fourth order one-dimensional (1D) polynomial expansion with five coefficients to be determined. The conditions necessary for coefficients determination are three average fluxes on consecutive surfaces of the three nodes and two fluxes in corners between these three surface fluxes. Corner fluxes of the node are determined using a third order 1D polynomial expansion with four coefficients. This reconstruction method uses heterogeneous nuclear parameters directly providing the heterogeneous neutron flux distribution and the detailed nuclear power density distribution within the FAs. The results obtained with this method has good accuracy and efficiency when compared with reference values.

Full scale seismic simulation of a nuclear reactor with parallel finite element analysis code for assembled structure

International Nuclear Information System (INIS)

Yamada, Tomonori

2010-01-01

The safety requirement of nuclear power plant attracts much attention nowadays. With the growing computing power, numerical simulation is one of key technologies to meet this safety requirement. Center for Computational Science and e-Systems of Japan Atomic Energy Agency has been developing a finite element analysis code for assembled structure to accurately evaluate the structural integrity of nuclear power plant in its entirety under seismic events. Because nuclear power plant is very huge assembled structure with tens of millions of mechanical components, the finite element model of each component is assembled into one structure and non-conforming meshes of mechanical components are bonded together inside the code. The main technique to bond these mechanical components is triple sparse matrix multiplication with multiple point constrains and global stiffness matrix. In our code, this procedure is conducted in a component by component manner, so that the working memory size and computing time for this multiplication are available on the current computing environment. As an illustrative example, seismic simulation of a real nuclear reactor of High Temperature engineering Test Reactor, which is located at the O-arai research and development center of JAEA, with 80 major mechanical components was conducted. Consequently, our code successfully simulated detailed elasto-plastic deformation of nuclear reactor and its computational performance was investigated. (author)

Infinite nuclear matter based for mass of atomic nuclei

International Nuclear Information System (INIS)

Satpathy, L.

1987-01-01

The ground-state energy of an atomic nucleus with asymmetry β is considered to be equivalent to the energy of a perfect sphere made up of infinite nuclear matter of the same asymmetry plus a residual energy eta, called the local energy. Eta represents the energy due to shell, deformation, diffuseness and exchange Coulomb effects, etc. Using this picture and the generalised Hugenholtz-Van Hove theorem of many-body theory, the previously proposed mass relation is derived in a transport way in which eta drops away in a very natural manner. The validity of this mass relation is studied globally using the latest mass table. The model is suitable for the extraction of the saturation properties of nuclear matter. The binding energy per nucleon and the saturation Fermi momentum of nuclear matter obtained through this model are 18.33 MeV and 1.48 fm -1 respectively. It is shown in several representative cases in the Periodic Table that the masses of nuclei in the far unknown region can be reliably predicted. (author)

Probabilistic finite element investigation of prestressing loss in nuclear containment wall segments

International Nuclear Information System (INIS)

Balomenos, Georgios P.; Pandey, Mahesh D.

2017-01-01

Highlights: • Probabilistic finite element framework for assessing concrete strain distribution. • Investigation of prestressing loss based on concrete strain distribution. • Application to 3D nuclear containment wall segments. • Use of ABAQUS with python programing for Monte Carlo simulation. - Abstract: The main function of the concrete containment structures is to prevent radioactive leakage to the environment in case of a loss of coolant accident (LOCA). The Canadian Standard CSA N287.6 (2011) proposes periodic inspections, i.e., pressure testing, in order to assess the strength and design criteria of the containment (proof test) and the leak tightness of the containment boundary (leakage rate test). During these tests, the concrete strains are measured and are expected to have a distribution due to several uncertainties. Therefore, this study aims to propose a probabilistic finite element analysis framework. Then, investigates the relationship between the concrete strains and the prestressing loss, in order to examine the possibility of estimating the average prestressing loss during pressure testing inspections. The results indicate that the concrete strain measurements during the leakage rate test may provide information with respect to the prestressing loss of the bonded system. In addition, the demonstrated framework can be further used for the probabilistic finite element analysis of real scale containments.

Probabilistic finite element investigation of prestressing loss in nuclear containment wall segments

Energy Technology Data Exchange (ETDEWEB)

Balomenos, Georgios P., E-mail: gbalomen@uwaterloo.ca; Pandey, Mahesh D., E-mail: mdpandey@uwaterloo.ca

2017-01-15

Highlights: • Probabilistic finite element framework for assessing concrete strain distribution. • Investigation of prestressing loss based on concrete strain distribution. • Application to 3D nuclear containment wall segments. • Use of ABAQUS with python programing for Monte Carlo simulation. - Abstract: The main function of the concrete containment structures is to prevent radioactive leakage to the environment in case of a loss of coolant accident (LOCA). The Canadian Standard CSA N287.6 (2011) proposes periodic inspections, i.e., pressure testing, in order to assess the strength and design criteria of the containment (proof test) and the leak tightness of the containment boundary (leakage rate test). During these tests, the concrete strains are measured and are expected to have a distribution due to several uncertainties. Therefore, this study aims to propose a probabilistic finite element analysis framework. Then, investigates the relationship between the concrete strains and the prestressing loss, in order to examine the possibility of estimating the average prestressing loss during pressure testing inspections. The results indicate that the concrete strain measurements during the leakage rate test may provide information with respect to the prestressing loss of the bonded system. In addition, the demonstrated framework can be further used for the probabilistic finite element analysis of real scale containments.

Instanton vacuum at finite density of quark matter

International Nuclear Information System (INIS)

Molodtsov, S.V.; Zinovjev, G.M.

2002-01-01

We study light quark interactions in the instanton liquid at finite quark/baryon number density analyzing chiral and diquark condensates and investigate the behaviors of quark dynamical mass and both condensates together with instanton liquid density as a function of quark chemical potential. We conclude the quark impact (estimated in the tadpole approximation) on the instanton liquid could shift color superconducting phase transition to higher values of the chemical potential bringing critical quark matter density to the values essentially higher than conventional nuclear one

New lumped-mass-stick model based on modal characteristics of structures: development and application to a nuclear containment building

Science.gov (United States)

Roh, Hwasung; Lee, Huseok; Lee, Jong Seh

2013-06-01

In this study, a new lumped-mass-stick model (LMSM) is developed based on the modal characteristics of a structure such as eigenvalues and eigenvectors. The simplified model, named the "frequency adaptive lumped-massstick model," hasonly a small number of stick elements and nodes to provide the same natural frequencies of the structure and is applied to a nuclear containment building. To investigate the numerical performance of the LMSM, a time history analysis is carried out on both the LMSM and the finite element model (FEM) for a nuclear containment building. A comparison of the results shows that the dynamic responses of the LMSM in terms of displacement and acceleration are almost identical to those of the FEM. In addition, the results in terms of fl oor response spectra at certain elevations are also in good agreement.

FEHMN 1.0: Finite element heat and mass transfer code

International Nuclear Information System (INIS)

Zyvoloski, G.; Dash, Z.; Kelkar, S.

1991-04-01

A computer code is described which can simulate non-isothermal multiphase multicomponent flow in porous media. It is applicable to natural-state studies of geothermal systems and ground-water flow. The equations of heat and mass transfer for multiphase flow in porous and permeable media are solved using the finite element method. The permeability and porosity of the medium are allowed to depend on pressure and temperature. The code also has provisions for movable air and water phases and noncoupled tracers; that is, tracer solutions that do not affect the heat and mass transfer solutions. The tracers can be passive or reactive. The code can simulate two-dimensional, two-dimensional radial, or three-dimensional geometries. A summary of the equations in the model and the numerical solution procedure are provided in this report. A user's guide and sample problems are also included. The main use of FEHMN will be to assist in the understanding of flow fields in the saturated zone below the proposed Yucca Mountain Repository. 33 refs., 27 figs., 12 tabs

Simulation of incompressible flows with heat and mass transfer using parallel finite element method

Directory of Open Access Journals (Sweden)

Jalal Abedi

2003-02-01

Full Text Available The stabilized finite element formulations based on the SUPG (Stream-line-Upwind/Petrov-Galerkin and PSPG (Pressure-Stabilization/Petrov-Galerkin methods are developed and applied to solve buoyancy-driven incompressible flows with heat and mass transfer. The SUPG stabilization term allows us to solve flow problems at high speeds (advection dominant flows and the PSPG term eliminates instabilities associated with the use of equal order interpolation functions for both pressure and velocity. The finite element formulations are implemented in parallel using MPI. In parallel computations, the finite element mesh is partitioned into contiguous subdomains using METIS, which are then assigned to individual processors. To ensure a balanced load, the number of elements assigned to each processor is approximately equal. To solve nonlinear systems in large-scale applications, we developed a matrix-free GMRES iterative solver. Here we totally eliminate a need to form any matrices, even at the element levels. To measure the accuracy of the method, we solve 2D and 3D example of natural convection flows at moderate to high Rayleigh numbers.

Theories of Variable Mass Particles and Low Energy Nuclear Phenomena

Science.gov (United States)

Davidson, Mark

2014-02-01

Variable particle masses have sometimes been invoked to explain observed anomalies in low energy nuclear reactions (LENR). Such behavior has never been observed directly, and is not considered possible in theoretical nuclear physics. Nevertheless, there are covariant off-mass-shell theories of relativistic particle dynamics, based on works by Fock, Stueckelberg, Feynman, Greenberger, Horwitz, and others. We review some of these and we also consider virtual particles that arise in conventional Feynman diagrams in relativistic field theories. Effective Lagrangian models incorporating variable mass particle theories might be useful in describing anomalous nuclear reactions by combining mass shifts together with resonant tunneling and other effects. A detailed model for resonant fusion in a deuterium molecule with off-shell deuterons and electrons is presented as an example. Experimental means of observing such off-shell behavior directly, if it exists, is proposed and described. Brief explanations for elemental transmutation and formation of micro-craters are also given, and an alternative mechanism for the mass shift in the Widom-Larsen theory is presented. If variable mass theories were to find experimental support from LENR, then they would undoubtedly have important implications for the foundations of quantum mechanics, and practical applications may arise.

Nolen-Schiffer anomaly and atomic masses

International Nuclear Information System (INIS)

Fayans, S. A.

1998-01-01

A new form of the nuclear energy-density functional for describing the ground state properties of finite nuclei up to the drip lines and beyond is proposed. The surface energy-density term has a fractional form containing (∇ρ) 2 both in the numerator and in the denominator. An effective ρ-dependent Coulomb-nuclear correlation term is added. A fit to the nuclear masses and radii shows that the latter term gives contribution of the same order of magnitude as the Nolen-Schiffer anomaly in Coulomb displacement energy. The self-consistent run with the suggested functional, performed for about 100 spherical nuclei, has given the rms deviations from the experiment of ≅1.2 Mev in masses and ≅0.01 fm in radii. The extrapolation to the drip lines goes in between the ETFSI and the macroscopic-microscopic model predictions

Steam Generator control in Nuclear Power Plants by water mass inventory

Energy Technology Data Exchange (ETDEWEB)

Dong Wei [North Carolina State University, Department of Nuclear Engineering, Box 7909, Raleigh, NC 27695-7909 (United States); Doster, J. Michael [North Carolina State University, Department of Nuclear Engineering, Box 7909, Raleigh, NC 27695-7909 (United States)], E-mail: doster@eos.ncsu.edu; Mayo, Charles W. [North Carolina State University, Department of Nuclear Engineering, Box 7909, Raleigh, NC 27695-7909 (United States)

2008-04-15

Control of water mass inventory in Nuclear Steam Generators is important to insure sufficient cooling of the nuclear reactor. Since downcomer water level is measurable, and a reasonable indication of water mass inventory near steady-state, conventional feedwater control system designs attempt to maintain downcomer water level within a relatively narrow operational band. However, downcomer water level can temporarily react in a reverse manner to water mass inventory changes, commonly known as shrink and swell effects. These complications are accentuated during start-up or low power conditions. As a result, automatic or manual control of water level is difficult and can lead to high reactor trip rates. This paper introduces a new feedwater control strategy for Nuclear Steam Generators. The new method directly controls water mass inventory instead of downcomer water level, eliminating complications from shrink and swell all together. However, water mass inventory is not measurable, requiring an online estimator to provide a mass inventory signal based on measurable plant parameters. Since the thermal-hydraulic response of a Steam Generator is highly nonlinear, a linear state-observer is not feasible. In addition, difficulties in obtaining flow regime and density information within the Steam Generator make an estimator based on analytical methods impractical at this time. This work employs a water mass estimator based on feedforward neural networks. By properly choosing and training the neural network, mass signals can be obtained which are suitable for stable, closed-loop water mass inventory control. Theoretical analysis and simulation results show that water mass control can significantly improve the operation and safety of Nuclear Steam Generators.

Steam Generator control in Nuclear Power Plants by water mass inventory

International Nuclear Information System (INIS)

Dong Wei; Doster, J. Michael; Mayo, Charles W.

2008-01-01

Control of water mass inventory in Nuclear Steam Generators is important to insure sufficient cooling of the nuclear reactor. Since downcomer water level is measurable, and a reasonable indication of water mass inventory near steady-state, conventional feedwater control system designs attempt to maintain downcomer water level within a relatively narrow operational band. However, downcomer water level can temporarily react in a reverse manner to water mass inventory changes, commonly known as shrink and swell effects. These complications are accentuated during start-up or low power conditions. As a result, automatic or manual control of water level is difficult and can lead to high reactor trip rates. This paper introduces a new feedwater control strategy for Nuclear Steam Generators. The new method directly controls water mass inventory instead of downcomer water level, eliminating complications from shrink and swell all together. However, water mass inventory is not measurable, requiring an online estimator to provide a mass inventory signal based on measurable plant parameters. Since the thermal-hydraulic response of a Steam Generator is highly nonlinear, a linear state-observer is not feasible. In addition, difficulties in obtaining flow regime and density information within the Steam Generator make an estimator based on analytical methods impractical at this time. This work employs a water mass estimator based on feedforward neural networks. By properly choosing and training the neural network, mass signals can be obtained which are suitable for stable, closed-loop water mass inventory control. Theoretical analysis and simulation results show that water mass control can significantly improve the operation and safety of Nuclear Steam Generators

Mass spectrometry in nuclear technology - a review of application of thermal ionization mass spectrometry in fuel reprocessing plants. PD-7-1

International Nuclear Information System (INIS)

Dakshinamoorthy, A.

2007-01-01

Mass spectrometry finds the widespread application in nuclear science and technology due to the fact that it can be employed for isotope composition measurements of different elements of interest and also concentration measurements of these elements using isotope dilution techniques. Thermal ionization mass spectrometer (TIMS), Inductively coupled plasma mass spectrometer (ICP-MS) and gas chromatography mass spectrometer (GC-MS) are the different types of mass spectrometers used in nuclear industry for the analyses of isotope composition of special nuclear material, trace impurities in nuclear fuels and components and characterization of various solvents respectively. Among them, TIMS plays a vital role in the nuclear fuel cycle in determining precisely the isotope composition of uranium, plutonium, D/H ratio in heavy water etc. TIMS is an indispensable analytical tool for nuclear material accounting at the input stage of a reprocessing plant by carrying out precise and accurate concentration measurement of plutonium and uranium by isotope dilution mass spectrometry (IDMS). It is the only accepted measurement technique for the purpose because of its high precision, better sensitivity and no quantitative separation is needed. The isotope abundance measurements of uranium and plutonium at this point are also useful for burn-up studies and isotope correlations. Mass spectrometric analysis of uranium and plutonium is also required for nuclear data measurements and calibrating other chemical methods

Burnup determination of mass spectrometry for nuclear fuels

International Nuclear Information System (INIS)

Zhang Chunhua.

1987-01-01

The various methods currently being used in burnup determination of nuclear fuels are studied and reviewed. The mass spectrometry method of destructive testing is discussed emphatically. The burnup determination of mass spectrometry includes heavy isotopic abundance ratio method and isotope dilution mass spectrometry used as burnup indicator for the fission products. The former is applied to high burnup level, but the later to various burnup level. According to experiences, some problems which should be noticed in burnup determination of mass spectrometry are presented

Finite size and dynamical effects in pair production by an external field

International Nuclear Information System (INIS)

Martin, C.; Vautherin, D.

1988-12-01

We evaluate the rate of pair production in a uniform electric field confined into a bounded region in space. Using the Balian-Bloch expansion of Green's functions we obtain explicit expressions for finite size corrections to Schwinger's formula. The case of a time-dependent boundary, relevant to describe energy deposition by quark-antiquark pair production in ultrarelativistic collisions, is also investigated. We find that finite size effects are important in nuclear collisions. They decrease when the strength of the chromo-electric field between the nuclei is large. As a result, the rate of energy deposition increases sharply with the mass number A of the colliding nuclei

Recent status of the studies of nuclear masses and β-decay

International Nuclear Information System (INIS)

Yamada, Masami

1996-01-01

The recent status of the above studies was explained, especially, nuclear masses were described from the aspect of probability theory and that of β-decay suggested that the first forbidden transition was hindered between the ground states. We have to study various systematics in order to know the mass surface, Way-Yamada-Matumoto type systematics is better to check the experimental nuclear masses. The gross theory is very useful to understand the general aspect of β-decay. The understanding method of mass surface, systematic check of mass and hindrance of the first forbidden transition at rank 1 were explained. (S.Y.)

Recent status of the studies of nuclear masses and {beta}-decay

Energy Technology Data Exchange (ETDEWEB)

Yamada, Masami [Waseda Univ., Tokyo (Japan). Advanced Research Center for Science and Engineering

1996-05-01

The recent status of the above studies was explained, especially, nuclear masses were described from the aspect of probability theory and that of {beta}-decay suggested that the first forbidden transition was hindered between the ground states. We have to study various systematics in order to know the mass surface, Way-Yamada-Matumoto type systematics is better to check the experimental nuclear masses. The gross theory is very useful to understand the general aspect of {beta}-decay. The understanding method of mass surface, systematic check of mass and hindrance of the first forbidden transition at rank 1 were explained. (S.Y.)

Assessment of soil/structure interaction analysis procedures for nuclear power plant structures

International Nuclear Information System (INIS)

Young, G.A.; Wei, B.C.

1977-01-01

The paper presents an assessment of two state-of-the-art soil/structure interaction analysis procedures that are frequently used to provide seismic analyses of nuclear power plant structures. The advantages of large three-dimensional, elastic, discrete mass models and two-dimensional finite element models are compared. The discrete mass models can provide three-dimensional response capability with economical computer costs but only fair soil/structure interaction representation. The two-dimensional finite element models provide good soil/structure interaction representation, but cannot provide out-of-plane response. Three-dimensional finite element models would provide the most informative and complete analyses. For this model, computer costs would be much greater, but modeling costs would be approximately the same as those required for three-dimensional discrete mass models

Onsets of nuclear deformation from measurements with the Isoltrap mass spectrometer

International Nuclear Information System (INIS)

Naimi, S.

2010-10-01

Mass measurements provide important information concerning nuclear structure. This work presents results from the pioneering Penning trap spectrometer Isoltrap at CERN-Isolde. High-precision mass measurements of neutron-rich manganese ( 58 - 66 Mn) and krypton isotopes ( 96, 97 Kr) are presented, of which the 66 Mn and 96, 97 Kr masses are measured for the first time. In particular, the mass of 97 Kr was measured using the preparation trap and required the definition of a new fit function. In the case of the manganese isotopes, the N=40 shell closure is addressed. The two-neutron-separation energies calculated from the new masses show no shell closure at N=40 but give an estimation of the proton-neutron interaction (around 0.5 MeV) responsible for the increase of collectivity and nuclear deformation in this mass region. The new krypton masses show behavior in sharp contrast with heavier neighbors where sudden and intense deformation is present, interpreted as the establishment of a nuclear quantum shape/phase transition critical-point boundary. The new masses confirm findings from nuclear mean-square charge-radius measurements up to N=60 but are at variance with conclusions from recent gamma-ray spectroscopy. Another part of this work was the design of new decay spectroscopy system behind the Isoltrap mass spectrometer. The beam purity achievable with Isoltrap will allow decay studies with γ and β detection coupled to a tape-station. This system has been mounted and commissioned with the radioactive beam 80 Rb. (author)

Application of accelerator mass spectrometry in nuclear science

International Nuclear Information System (INIS)

Wang Xiaobo; Hu Jinjun; Wang Huijuan; Guan Yongjing; Wang Wei

2013-01-01

Accelerator mass spectrometry (AMS) is a promising method to provide extreme sensitivity measurements of the production yields of long-lived radioisotopes, which cannot be detected by other methods. AMS technique plays an important role in the research of nuclear physics, as well as the application field of AMS covered nuclear science and technology, life science, earth science, environmental science, archaeology etc. The newest AMS field is that of actinide, particularly U and Pu, isotopic assay with expanding applications in nuclear safeguards and monitoring, and as a modern bomb-fallout tracer for atmospheric transport and surface sediment movement. This paper reviews the applications of AMS in the research of nuclear energy and nuclear security including the research of half life of radionuclides, cross section of nuclear reaction. (authors)

Estimation of unknown nuclear masses by means of the generalized mass relations. Pt. 3

International Nuclear Information System (INIS)

Popa, S.M.

1980-01-01

A survey of the estimations of the unknown nuclear masses by means of the generalized mass relations is presented. One discusses the new hypotheses supplementing the original general Garvey-Kelson scheme, reviewing the generalized mass relations and formulae, according to the present status of this new formalism. A critical discussions is given of the reliability of these new Garvey-Kelson type extrapolation procedures. (author)

Nuclear masses, deformations and shell effects

International Nuclear Information System (INIS)

Hirsch, Jorge G; Barbero, César A; Mariano, Alejandro E

2011-01-01

We show that the Liquid Drop Model is best suited to describe the masses of prolate deformed nuclei than of spherical nuclei. To this end three Liquid Drop Mass formulas are employed to describe nuclear masses of eight sets of nuclei with similar quadrupole deformations. It is shown that they are able to fit the measured masses of prolate deformed nuclei with an RMS smaller than 750 keV, while for the spherical nuclei the RMS is, in the three cases, larger than 2000 keV. The RMS of the best fit of the masses of semi-magic nuclei is also larger than 2000 keV. The parameters of the three models are studied, showing that the surface symmetry term is the one which varies the most from one group of nuclei to another. In one model, isospin dependent terms are also found to exhibit strong changes. The inclusion of shell effects allows for better fits, which continue to be better in the prolate deformed nuclei region.

Bootstrap calculation of the dynamical quark mass in QCD4 at finite temperature

International Nuclear Information System (INIS)

Cabo, A.; Kalashnikov, O.K.; Veliev, E.Kh.

1988-01-01

Nonperturbative calculations of the dynamical quark mass m(T) are given in QCD 4 , based on the bootstrap solution of the Schwinger-Dyson equation for the quark Green function at finite temperatures. A closed nonlinear equation is obtained for m(T) whose solution is found under some simplifying assumptions. We used a particular approximation for the effective charge and the nonperturbative expressions of the gluon magnetic and electric masses. The singular behavior of m(T) is established and its parameters are determined numerically. The singularity found is shown to correctly reproduce the chiral phase transition and the temperature limits obtained for m(T) are qualitatively correct. The complete phase diagram of QCD 4 in the (μ,T) plane is briefly discussed. (orig.)

Deformation and shell effects in nuclear mass formulas

International Nuclear Information System (INIS)

Barbero, César; Hirsch, Jorge G.; Mariano, Alejandro E.

2012-01-01

We analyze the ability of three different Liquid Drop Mass (LDM) formulas to describe nuclear masses for nuclei in various deformation regions. Separating the 2149 measured nuclear species into eight sets with similar quadrupole deformations, we show that the masses of prolate deformed nuclei are better described than those of spherical ones. In fact, the prolate deformed nuclei are fitted with an RMS smaller than 750 keV, while for spherical and semi-magic species the RMS is always larger than 2000 keV. These results are found to be independent of pairing. It is also shown that the macroscopic sector of the Duflo–Zuker (DZ) mass model reproduces shell effects, while most of the deformation dependence is lost and the RMS is larger than in any LDM. Adding to the LDM the microscopically motivated DZ master terms introduces the shell effects, allowing for a significant reduction in the RMS of the fit but still exhibiting a better description of prolate deformed nuclei. The inclusion of shell effects following the Interacting Boson Model's ideas produces similar results.

Deformation and shell effects in nuclear mass formulas

Energy Technology Data Exchange (ETDEWEB)

Barbero, Cesar [Departamento de Fisica, Universidad Nacional de La Plata, C.C. 67, 1900 La Plata (Argentina); Instituto de Fisica La Plata, CONICET, 1900 La Plata (Argentina); Hirsch, Jorge G., E-mail: hirsch@nucleares.unam.mx [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, 04510 Mexico D.F. (Mexico); Mariano, Alejandro E. [Departamento de Fisica, Universidad Nacional de La Plata, C.C. 67, 1900 La Plata (Argentina); Instituto de Fisica La Plata, CONICET, 1900 La Plata (Argentina)

2012-01-15

We analyze the ability of three different Liquid Drop Mass (LDM) formulas to describe nuclear masses for nuclei in various deformation regions. Separating the 2149 measured nuclear species into eight sets with similar quadrupole deformations, we show that the masses of prolate deformed nuclei are better described than those of spherical ones. In fact, the prolate deformed nuclei are fitted with an RMS smaller than 750 keV, while for spherical and semi-magic species the RMS is always larger than 2000 keV. These results are found to be independent of pairing. It is also shown that the macroscopic sector of the Duflo-Zuker (DZ) mass model reproduces shell effects, while most of the deformation dependence is lost and the RMS is larger than in any LDM. Adding to the LDM the microscopically motivated DZ master terms introduces the shell effects, allowing for a significant reduction in the RMS of the fit but still exhibiting a better description of prolate deformed nuclei. The inclusion of shell effects following the Interacting Boson Model's ideas produces similar results.

Investigation of the proton-neutron interaction by high-precision nuclear mass measurements

CERN Multimedia

Savreux, R P; Akkus, B

2007-01-01

We propose to measure the atomic masses of a series of short-lived nuclides, including $^{70}$Ni, $^{122-130}$Cd, $^{134}$Sn, $^{138,140}$Xe, $^{207-210}$Hg, and $^{223-225}$Rn, that contribute to the investigation of the proton-neutron interaction and its role in nuclear structure. The high-precision mass measurements are planned for the Penning trap mass spectrometer ISOLTRAP that reaches the required precision of 10 keV in the nuclear mass determination.

Diffusion of heat from a finite, rectangular, plane heat source

International Nuclear Information System (INIS)

Ferreri, J.C.; Caballero, C.H.

1985-01-01

Non-dimensional results for the temperature field originating in a rectangular, finite, plane heat source with infinitesimal thickness are introduced. The source decays in time, zero decay being a particular case. Results are useful for obtaining an aproximation of the maximum temperature of a system holding an internal heat source. The range selected for the parameters is specially useful in the case of a nuclear waste repository. The application to the case of mass diffussion arises from analogy. (Author) [es

Finite nuclear size and Lamb shift of p-wave atomic states

International Nuclear Information System (INIS)

Milstein, A.I.; Sushkov, O.P.; Terekhov, I.S.

2003-01-01

We consider corrections to the Lamb shift of the p-wave atomic states due to the finite nuclear size (FNS). In other words, these are radiative corrections to the atomic isotope shift related to the FNS. It is shown that the structure of the corrections is qualitatively different to that for the s-wave states. The perturbation theory expansion for the relative correction for a p 1/2 state starts with a α ln(1/Zα) term, while for the s 1/2 states it starts with a Zα 2 term. Here, α is the fine-structure constant and Z is the nuclear charge. In the present work, we calculate the α terms for that 2p states, the result for the 2p 1/2 state reads (8α/9π){ln[1/(Zα) 2 ]+0.710}. Even more interesting are the p 3/2 states. In this case the 'correction' is several orders of magnitude larger than the 'leading' FNS shift. However, absolute values of energy shifts related to these corrections are very small

Thomas Fermi model of finite nuclei

International Nuclear Information System (INIS)

Boguta, J.; Rafelski, J.

1977-01-01

A relativistic Thomas-Fermi model of finite-nuclei is considered. The effective nuclear interaction is mediated by exchanges of isoscalar scalar and vector mesons. The authors include also a self-interaction of the scalar meson field and the Coulomb repulsion of the protons. The parameters of the model are constrained by the average nuclear properties. The Thomas-Fermi equations are solved numerically for finite, stable nuclei. The particular case of 208 82 Pb is considered in more detail. (Auth.)

Nuclear mass formula with the shell energies obtained by a new method

International Nuclear Information System (INIS)

Koura, H.; Tachibana, T.; Yamada, M.; Uno, M.

1998-01-01

Nuclear shapes and masses are estimated by a new method. The main feature of this method lies in estimating shell energies of deformed nuclei from spherical shell energies by mixing them with appropriate weights. The spherical shell energies are calculated from single-particle potentials, and, till now, two mass formulas have been constructed from two different sets of potential parameters. The standard deviation of the calculated masses from all the experimental masses of the 1995 Mass Evaluation is about 760 keV. Contrary to the mass formula by Tachibana, Uno, Yamada and Yamada in the 1987-1988 Atomic Mass Predictions, the present formulas can give nuclear shapes and predict on super-heavy elements

Centre de Spectrometrie Nucleaire et de Spectrometrie de Masse - CSNSM/Centre for nuclear and mass spectroscopy, Activity Report 2002-2004

International Nuclear Information System (INIS)

2005-01-01

The Centre for nuclear and mass spectroscopy (CSNSM) is a CNRS (National Centre for Scientific Research) laboratory affiliated with Paris-Sud University. The CSNSM is involved in pluri-disciplinary activities covering various scientific domains: Nuclear Structure (SNO), Nuclear Astrophysics (AN), Solid State Astrophysics (AS), Solid State Physics (PS) and Chemical Physics of Irradiation. This document presents the activity of the Centre during the 2002-2004 years: 1 - Foreword; 2 - Nuclear structure; 3 - EFIX: study of exotic nuclei-induced fission; 4 - Nuclear Astrophysics; 5 - Atomic mass; 6 - Solid state astrophysics; 7 - Accelerator-based mass spectroscopy; 8 - Solid State Physics; 9 - Physics and Chemistry of Irradiation; 10 - Activities of general interest; 11 - SEMIRAMIS (ion source and ion beam handling); 12 - Computer Department; 13 - Electronics Group; 14 - Mechanics Department; 15 - Health and safety; 16 - Permanent training; 17 - Seminars; 18 - PhDs; 19 - Staff

Mass-spectrometric measurements for nuclear safeguards

International Nuclear Information System (INIS)

Carter, J.A.; Smith, D.H.; Walker, R.L.

1982-01-01

The need of an on-site inspection device to provide isotopic ratio measurements led to the development of a quadrupole mass spectrometer mounted in a van. This mobile laboratory has the ability, through the use of the resin bead technique, to acquire, prepare, and analyze samples of interest to nuclear safeguards. Precision of the measurements is about 1 to 2%

Comparative research of finite element methods for perforated structures of nuclear power plant primary equipment

International Nuclear Information System (INIS)

Xiong Guangming; Deng Xiaoyun; Jin Ting

2013-01-01

Many perforated structures are used for nuclear power plant primary equipment, and they are complex, and have various forms. In order to explore the analysis and evaluation method, this paper used finite element method and equivalent analytic method to do the comparative analysis of perforated structures. The paper considered the main influence factors (including perforated forms, arrangements, and etc.), obtaining the systematic analysis methods of perforated structures. (authors)

Pions in the nuclear medium

International Nuclear Information System (INIS)

Chanfray, G.

1996-07-01

We discuss various aspects of pion physics in the nuclear medium. We first study s-wave pion-nucleus interaction in connection with chiral symmetry restoration and quark condensate in the nuclear medium. We then address the question of p-wave pion-nucleus interaction and collective pionic modes in nuclei and draw the consequences for in medium ππ correlations especially in the scalar-isoscalar channel. We finally discuss the modification of the rho meson mass spectrum at finite density and/or temperature in connection with relativistic heavy ion collisions

UPDATED MASS SCALING RELATIONS FOR NUCLEAR STAR CLUSTERS AND A COMPARISON TO SUPERMASSIVE BLACK HOLES

International Nuclear Information System (INIS)

Scott, Nicholas; Graham, Alister W.

2013-01-01

We investigate whether or not nuclear star clusters and supermassive black holes (SMBHs) follow a common set of mass scaling relations with their host galaxy's properties, and hence can be considered to form a single class of central massive object (CMO). We have compiled a large sample of galaxies with measured nuclear star cluster masses and host galaxy properties from the literature and fit log-linear scaling relations. We find that nuclear star cluster mass, M NC , correlates most tightly with the host galaxy's velocity dispersion: log M NC = (2.11 ± 0.31)log (σ/54) + (6.63 ± 0.09), but has a slope dramatically shallower than the relation defined by SMBHs. We find that the nuclear star cluster mass relations involving host galaxy (and spheroid) luminosity and stellar and dynamical mass, intercept with but are in general shallower than the corresponding black hole scaling relations. In particular, M NC ∝M 0.55±0.15 Gal,dyn ; the nuclear cluster mass is not a constant fraction of its host galaxy or spheroid mass. We conclude that nuclear stellar clusters and SMBHs do not form a single family of CMOs.

A finite quantum gravity

International Nuclear Information System (INIS)

Meszaros, A.

1984-05-01

In case the graviton has a very small non-zero mass, the existence of six additional massive gravitons with very big masses leads to a finite quantum gravity. There is an acausal behaviour on the scales that is determined by the masses of additional gravitons. (author)

Centre de Spectrometrie Nucleaire et de Spectrometrie de Masse - CSNSM/Centre for nuclear and mass spectroscopy, Activity Report 1985-1986-1987

International Nuclear Information System (INIS)

2003-01-01

The Centre for nuclear and mass spectroscopy (CSNSM) is a CNRS (National Centre for Scientific Research) laboratory affiliated with Paris-Sud University. The CSNSM is involved in pluri-disciplinary activities covering various scientific domains: Nuclear Structure (SNO), Nuclear Astrophysics (AN), Solid State Astrophysics (AS), Solid State Physics (PS) and Chemical Physics of Irradiation. This document presents the activity of the Centre during the 1985-1986-1987 years: 1 - Teams presentation; 2 - Abstracts: On the borderline of spectroscopy; Atomic spectroscopy and low-energy low-spin nuclear structure; high-energy high-spin nuclear structure; Theories and models; Nuclear astrophysics; Accelerator-based mass spectroscopy; Solid State Physics; Study of charged particles irradiation effects in astrophysics, geophysics and material sciences; Technical developments for the RF mass spectrometer and for Obelix; Technical developments for ion beams; Technical developments in electronics and their applications; CNSM's Computer Department; Developments in cryogenics; 3 - Staff and publications

Software requirements, design, and verification and validation for the FEHM application - a finite-element heat- and mass-transfer code

International Nuclear Information System (INIS)

Dash, Z.V.; Robinson, B.A.; Zyvoloski, G.A.

1997-07-01

The requirements, design, and verification and validation of the software used in the FEHM application, a finite-element heat- and mass-transfer computer code that can simulate nonisothermal multiphase multicomponent flow in porous media, are described. The test of the DOE Code Comparison Project, Problem Five, Case A, which verifies that FEHM has correctly implemented heat and mass transfer and phase partitioning, is also covered

ChPT loops for the lattice: pion mass and decay constant, HVP at finite volume and nn̅-oscillations

Science.gov (United States)

Bijnens, Johan

2018-03-01

I present higher loop order results for several calculations in Chiral perturbation Theory. 1) Two-loop results at finite volume for hadronic vacuum polarization. 2) A three-loop calculation of the pion mass and decay constant in two-flavour ChPT. For the pion mass all needed auxiliary parameters can be determined from lattice calculations of ππ-scattering. 3) Chiral corrections to neutron-anti-neutron oscillations.

Onsets of nuclear deformation from measurements with the Isoltrap mass spectrometer

CERN Document Server

Naimi, Sarah

Mass measurements provide important information concerning nuclear structure. This work presents results from the pioneering Penning trap spectrometer ISOLTRAP at CERN-ISOLDE. High-precision mass measurements of neutron-rich manganese ($^{58−66}$Mn) and krypton isotopes ($^{96,97}$Kr) are presented, of which the $^{66}$Mn and $^{96,97}$Kr masses are measured for the first time. In particular, the mass of $^{97}$Kr was measured using the preparation trap and required the definition of a new fit function. In the case of the manganese isotopes, the N = 40 shell closure is addressed. The two-neutron-separation energies calculated from the new masses show no shell closure at N = 40 but give an estimation of the proton-neutron interaction (around 0.5 MeV) responsible for the increase of collectivity and nuclear deformation in this mass region. The new krypton masses show behavior in sharp contrast with heavier neighbors where sudden and intense deformation is present, interpreted as the establishment of a nuclea...

$\\delta$-Expansion at Finite Temperature

OpenAIRE

Ramos, Rudnei O.

1996-01-01

We apply the $\\delta$-expansion perturbation scheme to the $\\lambda \\phi^{4}$ self-interacting scalar field theory in 3+1 D at finite temperature. In the $\\delta$-expansion the interaction term is written as $\\lambda (\\phi^{2})^{ 1 + \\delta}$ and $\\delta$ is considered as the perturbation parameter. We compute within this perturbative approach the renormalized mass at finite temperature at a finite order in $\\delta$. The results are compared with the usual loop-expansion at finite temperature.

Masses of the Goldstone modes in the CFL phase of QCD at finite density

CERN Document Server

Manuel, C; Manuel, Cristina; Tytgat, Michel H. G.

2000-01-01

We construct the U_L(3) x U_R(3) effective lagrangian which encodes the dynamics of the low energy pseudoscalar excitations in the Color-Flavor-Locking superconducting phase of QCD at finite quark density. We include the effects of instanton-induced interactions and study the mass pattern of the pseudoscalar mesons. A tentative comparison with the analytical estimate for the gap suggests that some of these low energy momentum modes are not stable for moderate values of the quark chemical potential.

Improved Nuclear Reactor and Shield Mass Model for Space Applications

Science.gov (United States)

Robb, Kevin

2004-01-01

New technologies are being developed to explore the distant reaches of the solar system. Beyond Mars, solar energy is inadequate to power advanced scientific instruments. One technology that can meet the energy requirements is the space nuclear reactor. The nuclear reactor is used as a heat source for which a heat-to-electricity conversion system is needed. Examples of such conversion systems are the Brayton, Rankine, and Stirling cycles. Since launch cost is proportional to the amount of mass to lift, mass is always a concern in designing spacecraft. Estimations of system masses are an important part in determining the feasibility of a design. I worked under Michael Barrett in the Thermal Energy Conversion Branch of the Power & Electric Propulsion Division. An in-house Closed Cycle Engine Program (CCEP) is used for the design and performance analysis of closed-Brayton-cycle energy conversion systems for space applications. This program also calculates the system mass including the heat source. CCEP uses the subroutine RSMASS, which has been updated to RSMASS-D, to estimate the mass of the reactor. RSMASS was developed in 1986 at Sandia National Laboratories to quickly estimate the mass of multi-megawatt nuclear reactors for space applications. In response to an emphasis for lower power reactors, RSMASS-D was developed in 1997 and is based off of the SP-100 liquid metal cooled reactor. The subroutine calculates the mass of reactor components such as the safety systems, instrumentation and control, radiation shield, structure, reflector, and core. The major improvements in RSMASS-D are that it uses higher fidelity calculations, is easier to use, and automatically optimizes the systems mass. RSMASS-D is accurate within 15% of actual data while RSMASS is only accurate within 50%. My goal this summer was to learn FORTRAN 77 programming language and update the CCEP program with the RSMASS-D model.

Nuclear mass formulas and its application for astrophysics

International Nuclear Information System (INIS)

Koura, Hiroyuki

2003-01-01

Some nuclear mass formulae are reviewed and applied for the calculation of the rapid neutron-capture-process (r-process) nucleosynthesis. A new mass formula composed of the gross term, the even-odd term, and the shell term is also presented. The new mass formula is a revised version of the spherical basis mass formula published in 2001, that is, the even-odd term is treated more carefully, and a considerable improvement is brought about. The root-mean-square deviation of the new formula from experimental masses is 641 keV for Z ≥ 8 and N ≥ 8. Properties on systematic of the neutron-separation energy is compared with some mass formulas. The calculated abundances of the r-process from different mass formulae are compared with use of a simple reaction model, and the relation between the calculated abundances and the corresponding masses are discussed. Furthermore, fission barriers for the superheavy and neutron-rich nuclei are also applied for the endpoint of the r-process. (author)

ChPT loops for the lattice: pion mass and decay constant, HVP at finite volume and nn̅-oscillations

Directory of Open Access Journals (Sweden)

Bijnens Johan

2018-01-01

Full Text Available I present higher loop order results for several calculations in Chiral perturbation Theory. 1 Two-loop results at finite volume for hadronic vacuum polarization. 2 A three-loop calculation of the pion mass and decay constant in two-flavour ChPT. For the pion mass all needed auxiliary parameters can be determined from lattice calculations of ππ-scattering. 3 Chiral corrections to neutron-anti-neutron oscillations.

Thomas-Fermi approach to nuclear mass formula. Pt. 1

International Nuclear Information System (INIS)

Dutta, A.K.; Arcoragi, J.P.; Pearson, J.M.; Tondeur, F.

1986-01-01

With a view to having a more secure basis for the nuclear mass formula than is provided by the drop(let) model, we make a preliminary study of the possibilities offered by the Skyrme-ETF method. Two ways of incorporating shell effects are considered: the ''Strutinsky-integral'' method of Chu et al., and the ''expectation-value'' method of Brack et al. Each of these methods is compared with the HF method in an attempt to see how reliably they extrapolate from the known region of the nuclear chart out to the neutron-drip line. The Strutinsky-integral method is shown to perform particularly well, and to offer a promising approach to a more reliable mass formula. (orig.)

Applications of accelerator mass spectrometry to nuclear physics and astrophysics

International Nuclear Information System (INIS)

Guo Zhiyu; Zhang Chuan

2002-01-01

As an ultra high sensitive analyzing method, accelerator mass spectrometry is playing an important role in the studies of nuclear physics and astrophysics. The accelerator mass spectrometry (AMS) applications in searching for violation of Pauli exclusion principle and study on supernovae are discussed as examples

Finite size effects in liquid-gas phase transition of asymmetric nuclear matter

International Nuclear Information System (INIS)

Pawlowski, P.

2001-01-01

Full text: Since the nuclear equation of state has been studied in astrophysical context as an element of neutron star or super-nova theories - a call for an evidence was produced in experimental nuclear physics. Heavy-ion collisions became a tool of study on thermodynamic properties of nuclear matter. A particular interest has been inspired here by critical behavior of nuclear systems, as a phase transition of liquid-gas type. A lot of efforts was put to obtain an experimental evidence of such a phenomenon in heavy-ion collisions. With the use of radioactive beams and high performance identification systems in a near future it will be possible to extend experimental investigation to asymmetric nuclear systems, where neutron-to-proton ratio is far from the stability line. This experimental development needs a corresponding extension of theoretical studies. To obtain a complete theory of the liquid-gas phase transition in small nuclear systems, produced in violent heavy-ion collisions, one should take into account two facts. First, that the nuclear matter forming nuclei is composed of protons and neutrons; this complicates the formalism of phase transitions because one has to deal with two separate, proton and neutron, densities and chemical potentials. The second and more important is that the surface effects are very strong in a system composed of a few hundreds of nucleons. This point is especially difficult to hold, because surface becomes an additional, independent state parameter, depending strongly on the geometrical configuration of the system, and introducing a non-local term in the equation of state. In this presentation we follow the recent calculation by Lee and Mekjian on the finite-size effects in small (A = 10 2 -10 3 ) asymmetric nuclear systems. A zero-range isospin-dependent Skyrme force is used to obtain a density and isospin dependent potential. The potential is then completed by additional terms giving contributions from surface and Coulomb

Shell finite element of reinforced concrete for internal pressure analysis of nuclear containment building

Energy Technology Data Exchange (ETDEWEB)

Lee, Hong Pyo, E-mail: hplee@kepri.re.k [Nuclear Power Laboratory, Korea Electric Power Research Institute, 103-16 Munji-Dong, Yuseong-Gu, Daejeon 305-380 (Korea, Republic of)

2011-02-15

Research highlights: Finite element program with 9-node degenerated shell element was developed. The developed program was mainly forced to analyze nuclear containment building. Concrete material model is adapted Niwa and Yamada failure criteria. The performance of program developed is verified through various numerical examples. The numerical analysis results similar to the experimental data. - Abstract: This paper describes a 9-node degenerated shell finite element (FE), an analysis program developed for ultimate pressure capacity evaluation and nonlinear analysis of a nuclear containment building. The shell FE developed adopts the Reissner-Mindlin (RM) assumptions to consider the degenerated shell solidification technique and the degree of transverse shear strain occurring in the structure. The material model of the concrete determines the level of the concrete stress and strain by using the equivalent stress-equivalent strain relationship. When a crack occurs in the concrete, the material behavior is expressed through the tension stiffening model that takes adhesive stress into account and through the shear transfer mechanism and compressive strength reduction model of the crack plane. In addition, the failure envelope proposed by Niwa is adopted as the crack occurrence criteria for the compression-tension region, and the failure envelope proposed by Yamada is used for the tension-tension region. The performance of the program developed is verified through various numerical examples. The analysis based on the application of the shell FE developed from the results of verified examples produced results similar to the experiment or other analysis results.

Equidistant structure and effective nucleon mass in nuclear matter

International Nuclear Information System (INIS)

Tezuka, Hirokazu.

1981-11-01

The effective nucleon mass of the Equidistant Multi-Layer Structure (EMULS) is discussed self-consistently. In the density region where the Fermi gas state in nuclear matter is unstable against the density fluctuation, the EMULS gives lower binding energy. It is, however, shown that such a structure with an ordinary nucleon mass collapses due to too strong attraction. We point out that such a collapse can be avoided by taking account of an effective nucleon mass affected by the localization of nucleons. (author)

Topics in quantum field theories at finite temperature

International Nuclear Information System (INIS)

Kao, Y.C.

1985-01-01

Studies on four topics in quantum field theories at finite temperature are presented in this thesis. In Chapter 1, it is shown that the chiral anomaly has no finite temperature corrections by Fujikawa's path integral approach. Chapter 2 deals with the chiral condensate in the finite temperature Schwinger model. The cluster decomposition property is employed to find . No finite critical temperature is found and the chiral condensate vanishes only at infinite temperature. In Chapter 3, the finite temperature behavior of the fermion-number breaking (Rubakov-Callan) condensate around a 't Hooft-Polyakov monopole is studied. It is found that the Rubakov-Callan condensate is suppressed exponentially from the monopole core at high temperature. The limitation of the techniques is understanding the behavior of the condensate for all temperature is also discussed. Chapter 4 is on the topological mass terms in (2 + 1)-dimensional gauge theories. The authors finds that if the gauge bosons have no topological mass at tree level, no topological mass induced radiatively up to two-loop order in either Abelian or non-Abelian theories with massive fermions. The Pauli-Villars regularization is used for fermion loops. The one-loop contributions to the topological mass terms at finite temperature are calculated and the quantization constraints in this case are discussed

Centre de Spectrometrie Nucleaire et de Spectrometrie de Masse - CSNSM/Centre for nuclear and mass spectroscopy, Activity Report 1992-1994

International Nuclear Information System (INIS)

2003-01-01

The Centre for nuclear and mass spectroscopy (CSNSM) is a CNRS (National Centre for Scientific Research) laboratory affiliated with Paris-Sud University. The CSNSM is involved in pluri-disciplinary activities covering various scientific domains: Nuclear Structure (SNO), Nuclear Astrophysics (AN), Solid State Astrophysics (AS), Solid State Physics (PS) and Chemical Physics of Irradiation. This document presents the activity of the Centre during the 1992-1994 years: 1 - Nuclear structure; 2 - Nuclear astrophysics; 3 - Basic symmetries; 4 - Accelerator-based mass spectroscopy; 5 - Solid State Astrophysics; 6 - Physics and Chemistry of Irradiation; 7 - Solid State Physics; 8 - SEMIRAMIS (ion source and ion beam handling); 9 - Computer Department; 10 - Electronics Group; 11 - Mechanics Department; 12 - Permanent training; 13 - Health and safety; 14 - Seminars; 15 - Dissertations; 16 - Publications; 17 - Staff

The nuclear waste issue in Swedish mass media

International Nuclear Information System (INIS)

Hedberg, P.

1991-04-01

This is an investigation of the representation given in the Swedish mass media of questions concerning the nuclear waste. The investigation covers the period from 1979 to 1989 of 8 newspapers of different political colours and the Swedish radio and television. (KAE)

Microscopically Based Nuclear Energy Functionals

International Nuclear Information System (INIS)

Bogner, S. K.

2009-01-01

A major goal of the SciDAC project 'Building a Universal Nuclear Energy Density Functional' is to develop next-generation nuclear energy density functionals that give controlled extrapolations away from stability with improved performance across the mass table. One strategy is to identify missing physics in phenomenological Skyrme functionals based on our understanding of the underlying internucleon interactions and microscopic many-body theory. In this contribution, I describe ongoing efforts to use the density matrix expansion of Negele and Vautherin to incorporate missing finite-range effects from the underlying two- and three-nucleon interactions into phenomenological Skyrme functionals.

Applications of a global nuclear-structure model to studies of the heaviest elements

International Nuclear Information System (INIS)

Moeller, P.; Nix, J.R.

1993-01-01

We present some new results on heavy-element nuclear-structure properties calculated on the basis of the finite-range droplet model and folded-Yukawa single-particle potential. Specifically, we discuss calculations of nuclear ground-state masses and microscopic corrections, α-decay properties, β-decay properties, fission potential-energy surfaces, and spontaneous-fission half-lives. These results, obtained in a global nuclear-structure approach, are particularly reliable for describing the stability properties of the heaviest elements

Meson dynamics and the nuclear many-body problem. II. Finite density Hartree-Fock

International Nuclear Information System (INIS)

Wilets, L.; Puff, R.D.; Chiang, D.; Nutt, W.T.

1976-01-01

The field-theoretic many-nucleon problem is formulated, and an analysis which sums all ''uncrossed meson line'' diagrams is investigated in detail. The calculation of energy per nucleon, after proper identification of infinite mass renormalization terms, exhibits effects of nuclear recoil, relativistic kinematics, and retardation. Numerical results are presented for π and ω mesons, and the nucleon interaction energies obtained are compared with the traditional static limit of infinite nucleon mass

Relativistic mean-field approximation with density-dependent screening meson masses in nuclear matter

International Nuclear Information System (INIS)

Sun, Baoxi; Lu, Xiaofu; Shen, Pengnian; Zhao, Enguang

2003-01-01

The Debye screening masses of the σ, ω and neutral ρ mesons and the photon are calculated in the relativistic mean-field approximation. As the density of the nucleon increases, all the screening masses of mesons increase. A different result with Brown–Rho scaling is shown, which implies a reduction in the mass of all the mesons in the nuclear matter, except the pion. Replacing the masses of the mesons with their corresponding screening masses in the Walecka-1 model, five saturation properties of the nuclear matter are fixed reasonably, and then a density-dependent relativistic mean-field model is proposed without introducing the nonlinear self-coupling terms of mesons. (author)

Characteristic relation for the mass and energy distribution of the nuclear fission products

International Nuclear Information System (INIS)

Alexandru, G.

1977-01-01

The dispersion relation for nuclear fission is written in the two part fragmentation approach which allows to obtain the characteristic relation for the mass and energy distribution of the nuclear fission products. One explains the resonance approximation in the mass distribution of the fission products taking into account the high order resonances too. (author)

System of equations of the quasiparticle-phonon nuclear model with allowance for phonon scattering at finite temperature

International Nuclear Information System (INIS)

Dang, N.D.

1986-01-01

The discovery of giant resonances in reactions of nuclei with heavy ions and in deep inelastic processes has stimulated interest in the study of the properties of highly excited nuclei. By taking into account exactly the population numbers of the single-phonon levels, the authors obtain a system of equations describing the interaction with the configurations in even-even spherical nuclei at a finite temperature. The Pauli principle is taken into account for the two-phonon components of the wave function of the excited states in accordance with an approximate procedure. The new diagrams associated with the introduction of the temperature are analyzed, and a comparison is made with the diagrams of nuclear field theory and the results of the theory of finite Fermi systems

Centre de Spectrometrie Nucleaire et de Spectrometrie de Masse - CSNSM/Centre for nuclear and mass spectroscopy, Activity Report 2001-2002

International Nuclear Information System (INIS)

2003-01-01

The Centre for nuclear and mass spectroscopy (CSNSM) is a CNRS (National Centre for Scientific Research) laboratory affiliated with Paris-Sud University. The CSNSM is involved in pluri-disciplinary activities covering various scientific domains: Nuclear Structure (SNO), Nuclear Astrophysics (AN), Solid State Astrophysics (AS), Solid State Physics (PS) and Chemical Physics of Irradiation. This document presents the activity of the Centre during the 2001-2002 years: 1 - Foreword; 2 - Research topics: Nuclear structure; EFIX: study of exotic nuclei-induced fission; Nuclear Astrophysics; Accelerator-based mass spectroscopy; Solid State Astrophysics; Physics and Chemistry of Irradiation; Solid State Physics; SEMIRAMIS (ion source and ion beam handling); Digest science; 3 - Publications; 4 - Dissertations; 5 - Seminars; 6 - Technical services: Computer Department; Electronics Group; Mechanics Department; Permanent training; Health and safety; 7 - Staff

Finite element method used in strength calculations of nuclear power plant pressure vessels

International Nuclear Information System (INIS)

Hanulak, E.

1987-01-01

A software system based on the use of the finite element method in linear and nonlinear elastomechanics was developed for assessing the strength and service life of steam generators and pressurizers for WWER type nuclear power plants. The individual programs are briefly described. They are written in FORTRAN IV, some modules are in ASSEMBLER. Programs EGUSAP, NEANKO, ROSYNA are designed for the calculation of stress and deformation, programs ROSYNA, NEANKO and NTEPLO are used for the calculation of temperature fields. Programs SPOJ and STATES are used for assessing the strength and service life of screw joints and other nodes of the WWER-440 type steam generators and pressurizers. (Z.M.)

RSMASS-D nuclear thermal propulsion and bimodal system mass models

Science.gov (United States)

King, Donald B.; Marshall, Albert C.

1997-01-01

Two relatively simple models have been developed to estimate reactor, radiation shield, and balance of system masses for a particle bed reactor (PBR) nuclear thermal propulsion concept and a cermet-core power and propulsion (bimodal) concept. The approach was based on the methodology developed for the RSMASS-D models. The RSMASS-D approach for the reactor and shield sub-systems uses a combination of simple equations derived from reactor physics and other fundamental considerations along with tabulations of data from more detailed neutron and gamma transport theory computations. Relatively simple models are used to estimate the masses of other subsystem components of the nuclear propulsion and bimodal systems. Other subsystem components include instrumentation and control (I&C), boom, safety systems, radiator, thermoelectrics, heat pipes, and nozzle. The user of these models can vary basic design parameters within an allowed range to achieve a parameter choice which yields a minimum mass for the operational conditions of interest. Estimated system masses are presented for a range of reactor power levels for propulsion for the PBR propulsion concept and for both electrical power and propulsion for the cermet-core bimodal concept. The estimated reactor system masses agree with mass predictions from detailed calculations with xx percent for both models.

Performance and scalability of finite-difference and finite-element wave-propagation modeling on Intel's Xeon Phi

NARCIS (Netherlands)

Zhebel, E.; Minisini, S.; Kononov, A.; Mulder, W.A.

2013-01-01

With the rapid developments in parallel compute architectures, algorithms for seismic modeling and imaging need to be reconsidered in terms of parallelization. The aim of this paper is to compare scalability of seismic modeling algorithms: finite differences, continuous mass-lumped finite elements

Toward finite quantum field theories

International Nuclear Information System (INIS)

Rajpoot, S.; Taylor, J.G.

1986-01-01

The properties that make the N=4 super Yang-Mills theory free from ultraviolet divergences are (i) a universal coupling for gauge and matter interactions, (ii) anomaly-free representations, (iii) no charge renormalization, and (iv) if masses are explicitly introduced into the theory, then these are required to satisfy the mass-squared supertrace sum rule Σsub(s=0.1/2)(-1)sup(2s+1)(2s+1)M 2 sub(s)=O. Finite N=2 theories are found to satisfy the above criteria. The missing member in this class of field theories are finite field theories consisting of N=1 superfields. These theories are discussed in the light of the above finiteness properties. In particular, the representations of all simple classical groups satisfying the anomaly-free and no-charge renormalization conditions for finite N=1 field theories are discussed. A consequence of these restrictions on the allowed representations is that an N=1 finite SU(5)-based model of strong and electroweak interactions can contain at most five conventional families of quarks and leptons, a constraint almost compatible with the one deduced from cosmological arguments. (author)

Computation of the velocity field and mass balance in the finite-element modeling of groundwater flow

International Nuclear Information System (INIS)

Yeh, G.T.

1980-01-01

Darcian velocity has been conventionally calculated in the finite-element modeling of groundwater flow by taking the derivatives of the computed pressure field. This results in discontinuities in the velocity field at nodal points and element boundaries. Discontinuities become enormous when the computed pressure field is far from a linear distribution. It is proposed in this paper that the finite element procedure that is used to simulate the pressure field or the moisture content field also be applied to Darcy's law with the derivatives of the computed pressure field as the load function. The problem of discontinuity is then eliminated, and the error of mass balance over the region of interest is much reduced. The reduction is from 23.8 to 2.2% by one numerical scheme and from 29.7 to -3.6% by another for a transient problem

Nuclear phenomena derived from quark-gluon strings

DEFF Research Database (Denmark)

Bohr, Henrik; Providencia, Constanca; Providencia, Joao da

2005-01-01

provided that the chiral fields are identified with the two-particle strings, which are natural in a QCD framework. Moreover, the model is able to reconcile qualitatively such aspects of hadronic physics as saturation density and binding energy of nuclear matter, surface density of finite nuclei, mass......, for the occurrence of the phases of nuclear matter. The model exhibits a quark deconfinement transition and chiral restoration, which are ingredients of QCD and give qualitatively correct numerics. The effective model is shown to be isomorphic to the Nambu-Jona-Lasinio model and exhibits the correct chirality...

Nuclear molecular structure in heavy mass systems

International Nuclear Information System (INIS)

Arctaedius, T.; Bargholtz, C.

1989-04-01

A study is made of nuclear molecular configurations involving one heavy mass partner. The stability of these configurations to mass flow and to fission is investigated as well as their population in fusion reactions. It is concluded that shell effects in combination with the effects of angular momentum may be important in stabilizing certain configurations. A possible relation of these configurations to the so called superdeformed states is pointed out. The spectrum of rotational and vibrational trasitions within molecular configurations is investigated. For sufficiently mass-asymmetric systems the engergies of vibrational transitions are comparable to the neutron separation energy. Gamma radiation from such transitions may then be observable above the background of statistical transitions. The gamma spectrum and the directional distribution of the radioation following fusion reactions with 12 C and 16 O are calculated. (authors)

Shell finite element of reinforced concrete for internal pressure analysis of nuclear containment building

International Nuclear Information System (INIS)

Lee, Hong Pyo

2011-01-01

Research highlights: → Finite element program with 9-node degenerated shell element was developed. → The developed program was mainly forced to analyze nuclear containment building. → Concrete material model is adapted Niwa and Yamada failure criteria. → The performance of program developed is verified through various numerical examples. → The numerical analysis results similar to the experimental data. - Abstract: This paper describes a 9-node degenerated shell finite element (FE), an analysis program developed for ultimate pressure capacity evaluation and nonlinear analysis of a nuclear containment building. The shell FE developed adopts the Reissner-Mindlin (RM) assumptions to consider the degenerated shell solidification technique and the degree of transverse shear strain occurring in the structure. The material model of the concrete determines the level of the concrete stress and strain by using the equivalent stress-equivalent strain relationship. When a crack occurs in the concrete, the material behavior is expressed through the tension stiffening model that takes adhesive stress into account and through the shear transfer mechanism and compressive strength reduction model of the crack plane. In addition, the failure envelope proposed by Niwa is adopted as the crack occurrence criteria for the compression-tension region, and the failure envelope proposed by Yamada is used for the tension-tension region. The performance of the program developed is verified through various numerical examples. The analysis based on the application of the shell FE developed from the results of verified examples produced results similar to the experiment or other analysis results.

Analysis of diffractive pd to Xd and pp to Xp interactions and test of the finite-mass sum rule

CERN Document Server

Akimov, Y; Golovanov, L B; Goulianos, K; Gross, D; Malamud, E; Melissinos, A C; Mukhin, S; Nitz, D; Olsen, S; Sticker, H; Tsarev, V A; Yamada, R; Zimmerman, P

1976-01-01

The first moment finite mass sum rule is tested by utilising cross- sections for pp to Xp extracted from recent Fermilab data on pd to Xd and also comparing with CERN ISR data. The dependences on M/sub x//sup 2/, t and s are also discussed. (11 refs).

Phase transitions in nuclear matter

International Nuclear Information System (INIS)

Glendenning, N.K.

1984-11-01

The rather general circumstances under which a phase transition in hadronic matter at finite temperature to an abnormal phase in which baryon effective masses become small and in which copious baryon-antibaryon pairs appear is emphasized. A preview is also given of a soliton model of dense matter, in which at a density of about seven times nuclear density, matter ceases to be a color insulator and becomes increasingly color conducting. 22 references

Mass shift of σ-meson in nuclear matter

International Nuclear Information System (INIS)

Morones-Ibarra, J.R.; Maciel, Mónica Menchaca; Padilla, Felipe Robledo; Santos-Guevara, Ayax

2013-01-01

The propagation of σ-meson in nuclear matter is studied in the Walecka model, by assuming that sigma couples to a pair of nucleon-antinucleon states to particle-hole states. The in-medium effect of σ-ω mixing is also studied. For completeness, the coupling of sigma to two virtual pions was also considered. It is found that the σ-meson mass decreases with respect to its value in vacuum and that the contribution of the σ-ω mixing effect on the mass shift is relatively small. (author)

Role of mass spectrometry in nuclear forensic science

International Nuclear Information System (INIS)

Joseph, M.; Sivaraman, N.

2016-01-01

The present talk will focus on the role of mass spectrometry in NFS in general; besides that, the various chromatographic methods developed towards separation of actinides and lanthanide fission products and characterization of dissolver solutions of nuclear reactor fuels using TIMS and some applications of using ICP-MS as well

Finite-element analysis of dynamic fracture

Science.gov (United States)

Aberson, J. A.; Anderson, J. M.; King, W. W.

1976-01-01

Applications of the finite element method to the two dimensional elastodynamics of cracked structures are presented. Stress intensity factors are computed for two problems involving stationary cracks. The first serves as a vehicle for discussing lumped-mass and consistent-mass characterizations of inertia. In the second problem, the behavior of a photoelastic dynamic tear test specimen is determined for the time prior to crack propagation. Some results of a finite element simulation of rapid crack propagation in an infinite body are discussed.

Pion properties at finite isospin chemical potential with isospin symmetry breaking

Science.gov (United States)

Wu, Zuqing; Ping, Jialun; Zong, Hongshi

2017-12-01

Pion properties at finite temperature, finite isospin and baryon chemical potentials are investigated within the SU(2) NJL model. In the mean field approximation for quarks and random phase approximation fpr mesons, we calculate the pion mass, the decay constant and the phase diagram with different quark masses for the u quark and d quark, related to QCD corrections, for the first time. Our results show an asymmetry between μI 0 in the phase diagram, and different values for the charged pion mass (or decay constant) and neutral pion mass (or decay constant) at finite temperature and finite isospin chemical potential. This is caused by the effect of isospin symmetry breaking, which is from different quark masses. Supported by National Natural Science Foundation of China (11175088, 11475085, 11535005, 11690030) and the Fundamental Research Funds for the Central Universities (020414380074)

Finite-volume scheme for anisotropic diffusion

Energy Technology Data Exchange (ETDEWEB)

Es, Bram van, E-mail: bramiozo@gmail.com [Centrum Wiskunde & Informatica, P.O. Box 94079, 1090GB Amsterdam (Netherlands); FOM Institute DIFFER, Dutch Institute for Fundamental Energy Research, The Netherlands" 1 (Netherlands); Koren, Barry [Eindhoven University of Technology (Netherlands); Blank, Hugo J. de [FOM Institute DIFFER, Dutch Institute for Fundamental Energy Research, The Netherlands" 1 (Netherlands)

2016-02-01

In this paper, we apply a special finite-volume scheme, limited to smooth temperature distributions and Cartesian grids, to test the importance of connectivity of the finite volumes. The area of application is nuclear fusion plasma with field line aligned temperature gradients and extreme anisotropy. We apply the scheme to the anisotropic heat-conduction equation, and compare its results with those of existing finite-volume schemes for anisotropic diffusion. Also, we introduce a general model adaptation of the steady diffusion equation for extremely anisotropic diffusion problems with closed field lines.

Self consitent description of nuclear level densitities

International Nuclear Information System (INIS)

Barranco, M.; Treiner, J.

1980-03-01

We present a self consistent calculation of the nuclear level density based on a generalization to finite temperature of a modified Thomas-Fermi method. A simple expression is derived for the so-called level density parameter a entering the expression of the density of states Xi(E)=Esup(-5/4)e 2 √aE and relating the excitation energy to the temperature E=a T 2 , in terms of nucleons equilibrium densities at T=0 only. One thus avoids the difficulty of adding external constraints to calculate isolated nuclei at finite temperature which are shown to be unstable against particle emission. The role of the nuclear surface is discussed. It is shown that the effective mass of the interaction plays a crucial role in determining the value of a and comparison with experiment confirms the value m*/m > = 1 near the Fermi level obtained through more microscopic analysis

On the time-stepping stability of continuous mass-lumped and discontinuous Galerkin finite elements for the 3D acoustic wave equation

NARCIS (Netherlands)

Zhebel, E.; Minisini, S.; Mulder, W.A.

2012-01-01

We solve the three-dimensional acoustic wave equation, discretized on tetrahedral meshes. Two methods are considered: mass-lumped continuous finite elements and the symmetric interior-penalty discontinuous Galerkin method (SIP-DG). Combining the spatial discretization with the leap-frog

Material constitutive model for jointed rock mass behavior

International Nuclear Information System (INIS)

Thomas, R.K.

1980-11-01

A material constitutive model is presented for jointed rock masses which exhibit preferred planes of weakness. This model is intended for use in finite element computations. The immediate application is the thermomechanical modelling of a nuclear waste repository in hard rock, but the model seems appropriate for a variety of other static and dynamic geotechnical problems as well. Starting with the finite element representations of a two-dimensional elastic body, joint planes are introduced in an explicit manner by direct modification of the material stiffness matrix. A novel feature of this approach is that joint set orientations, lengths and spacings are readily assigned through the sampling of a population distribution statistically determined from field measurement data. The result is that the fracture characteristics of the formations have the same statistical distribution in the model as is observed in the field. As a demonstration of the jointed rock mass model, numerical results are presented for the example problem of stress concentration at an underground opening

Nuclear structure studies of neutron-rich heavy nuclei by mass measurements of francium and radium isotopes

Energy Technology Data Exchange (ETDEWEB)

Rosenbusch, Marco [Ernst-Moritz-Arndt-Universitaet, Institut fuer Physik, 17487 Greifswald (Germany); Collaboration: ISOLTRAP-Collaboration

2013-07-01

The mass is a unique property of an atomic nucleus reflecting its binding energy and thus the sum of all interactions at work. Precise measurements of nuclear masses especially of short-lived exotic nuclides provide important input for nuclear structure, nuclear astrophysics, tests of the Standard Model, and weak interaction studies. The Penning-trap mass spectrometer ISOLTRAP at the on-line isotope separator ISOLDE/CERN has been set up for precision mass measurements and continuously improved for accessing more exotic nuclides. The mass uncertainty is typically δm / m=10{sup -8} and the accessible half-life has been reduced to about 50 ms. In this contribution, the results of a measurement campaign of neutron-rich francium and radium isotopes will be presented, i.e. the masses of the isotopic chain of {sup 224-233}Fr and {sup 233,234}Ra, one of the most neutron-rich ensemble obtainable at ISOL facilities. The mass {sup 234}Ra denotes the heaviest mass ever measured with ISOLTRAP. Experimental data in the neutron-rich, heavy mass region is of great interest for studies of structural evolution far from stability, especially because the knowledge from nuclear mass models is scarce. The impact of the new data on the physics in this mass region as well as recent technical developments of ISOLTRAP are discussed.

Effects of Brown-Rho scalings in nuclear matter, neutron stars and finite nuclei

Science.gov (United States)

Kuo, T. T. S.; Dong, Huan

2011-01-01

We have carried out calculations for nuclear matter, neutron stars and finite nuclei using NN potentials with and without the medium-dependent modifications based on the Brown-Rho (BR) scalings. Using the Vlow-k low-momentum interactions derived from such potentials, the equations of state (EOS) for symmetric and asymmetric nuclear matter, for densities up to ~ 5ρ0, are calculated using a RPA method where the particle-particle hole-hole ring diagrams are summed to all orders. The medium effects from both a linear BR scaling (BR1) and a non-linear one (BR2) are considered, and they both are essential for our EOSs to reproduce the nuclear matter saturation properties. For densities ρ below ρ0, results from BR1 and BR2 are close to each other. For higher densities, the EOS given by BR2 is more desirable and is well reproduced by that given by the interaction (Vlow-k+TBF) where Vlow-k is the unsealed low-momentum interaction and TBF is an empirical Skyrme three-body force. The moment of inertia of neutron stars is ~ 60 and ~ 25Modotkm2 respectively with and without the inclusion of the above BR2 medium effects. Effects from the BR scaling are important for the long half-life, ~ 5000yrs, of the 14C - 14N β-decay.

Centre de Spectrometrie Nucleaire et de Spectrometrie de Masse - CSNSM/Centre for nuclear and mass spectroscopy, Activity Report 1995-1997

International Nuclear Information System (INIS)

2003-01-01

The Centre for nuclear and mass spectroscopy (CSNSM) is a CNRS (National Centre for Scientific Research) laboratory affiliated with Paris-Sud University. The CSNSM is involved in pluri-disciplinary activities covering various scientific domains: Nuclear Structure (SNO), Nuclear Astrophysics (AN), Solid State Astrophysics (AS), Solid State Physics (PS) and Chemical Physics of Irradiation. This document presents the activity of the Centre during the 1995-1997 years: 1 - Nuclear structure: structure of first well states, superdeformation, high-spin state populations of stable or neutron-rich nuclei, high-k isomers physics, theoretical works, technical developments; 2 - Nuclear astrophysics; 3 - Basic symmetries; 4 - Accelerator-based mass spectroscopy; 5 - Solid State Astrophysics; 6 - Physics and Chemistry of Irradiation; 7 - Solid State Physics; 8 - SEMIRAMIS (ion source and ion beam handling); 9 - Computer Department; 10 - Electronics Group; 11 - Mechanics Department; 12 - Permanent training; 13 - Health and safety; 14 - Seminars and communications; 15 - Dissertations; 16 - Publications; 17 - Staff

The mass media and nuclear energy in the U.S

International Nuclear Information System (INIS)

Roche, C.

1994-01-01

The author discusses some problems of mass media of the United States connected with covering issues of nuclear power development, and makes some recommendations to improve the situation in this field

Determination of B and Li in nuclear materials by secondary-ion mass spectrometry

International Nuclear Information System (INIS)

Eby, R.E.; Christie, W.H.

1981-01-01

Secondary ion mass spectrometry (SIMS) was used to perform mass and isotopic analysis for B and Li in samples that are not readily amenable to more conventional mass spectrometric techniques (e.g., surface ionization, electron impact, etc.). In this paper three specific applications of SIMS analysis to nuclear materials are discussed: first, the quantitative determination of B and its isotopic composition in borosilicate glasses; second, the determination of the isotopic composition of B and Li in irradiated nuclear-grade aluminum oxide/boron carbide composite pellets, and, lastly, the quantitative and isotopic determination of B and Li in highly radioactive solutions of unknown composition

Quantum field theory and nuclear structure

International Nuclear Information System (INIS)

Celenza, L.S.; Goulard, B.; Shakin, C.M.

1981-01-01

We discuss recent successful calculations of the properties of nuclear matter within the context of theories exhibiting mass generation through spontaneous symmetry breaking. We start with the sigma model of Gell-Mann and Levy and introduce the nucleon mass (in a vacuum) in the usual manner. We relate the expectation value of the sigma field in a vacuum to a finite value of the scalar density. If the vacuum is now filled with nucleons (nuclear matter) the scalar density is increased and the new value for the nucleon mass must be determined. We exhibit the equation whose solution determines the new mass, and we also define a perturbative scheme for the determination of this mass. This scheme involves an expansion of the various quantities of the theory in terms of matrix elements calculated with positive- and negative-energy spinors parametrized with the vacuum mass. Although the decrease in the mass upon going from vacuum to nuclear matter at the equilibrium density is quite large (approx.400 MeV), we are still able to exhibit a small parameter which allows for a perturbative expansion of the binding energy and other observables. The leading term in such an expansion reproduces the approximation widely used in other calculations of the properties of nuclear matter. The truncation of the expansion at the leading term is inadequate and this fact accounts for the lack of success in previous calculations using the standard formalism. We proceed to make a transformation to the Weinberg Lagrangian retaining the fluctuating parts of the sigma field. We further make a small-oscillation approximation, dropping the nonlinear terms in this Lagrangian

Unified model of nuclear mass and level density formulas

International Nuclear Information System (INIS)

Nakamura, Hisashi

2001-01-01

The objective of present work is to obtain a unified description of nuclear shell, pairing and deformation effects for both ground state masses and level densities, and to find a new set of parameter systematics for both the mass and the level density formulas on the basis of a model for new single-particle state densities. In this model, an analytical expression is adopted for the anisotropic harmonic oscillator spectra, but the shell-pairing correlation are introduced in a new way. (author)

Research in theoretical nuclear physics, Nuclear Theory Group. Progress report

International Nuclear Information System (INIS)

Brown, G.E.; Jackson, A.D.; Kuo, T.T.S.

1984-01-01

Primary emphasis is placed on understanding the nature of nucleon-nucleon and meson-nucleon interactions and on determining the consequences of such microscopic interactions in nuclear systems. We have constructed models of baryons which smoothly interpolate between currently popular bag and Skyrme models of hadrons and provide a vehicle for introducing the notions of quantum chromodynamics to low energy nuclear physics without violating the constraints of chiral invariance. Such models have been used to study the nucleon-nucleon interaction, the spectrum of baryons, and the important question of the radius of the quark bag. We have used many-body techniques to consider a variety of problems in finite nuclei and infinite many-body systems. New light has been shed on the nuclear coexistence of spherical and deformed states in the A = 18 region as well as the role of genuine three-body forces in this region. Phenomenological studies of infinite systems have led to a number of predictions particularly regarding the spin-polarized quantum liquids of current experimental interest. Microscopic many-body theories, based on the parquet diagrams, have been improved to a fully quantitative level for the ground state properties of infinite many-body systems. Finite temperature theories of nuclear matter, important in the study of heavy ion reactions, have been constructed. An expanded program in heavy ion theory has led to major advances in the multi-dimensional barrier penetration problem. Activities in nuclear astrophysics have provided a far more reliable description of the role of electron capture processes in stellar collapse. As a consequence, we have been able to perform legitimate calculations of the unshocked mass in Type II supernovae

Finite unified models

Energy Technology Data Exchange (ETDEWEB)

Kapetanakis, D. (Technische Univ. Muenchen, Garching (Germany). Physik Dept.); Mondragon, M. (Technische Univ. Muenchen, Garching (Germany). Physik Dept.); Zoupanos, G. (National Technical Univ., Athens (Greece). Physics Dept.)

1993-09-01

We present phenomenologically viable SU(5) unified models which are finite to all orders before the spontaneous symmetry breaking. In the case of two models with three families the top quark mass is predicted to be 178.8 GeV. (orig.)

Finite unified models

International Nuclear Information System (INIS)

Kapetanakis, D.; Mondragon, M.; Zoupanos, G.

1993-01-01

We present phenomenologically viable SU(5) unified models which are finite to all orders before the spontaneous symmetry breaking. In the case of two models with three families the top quark mass is predicted to be 178.8 GeV. (orig.)

Parametric study for welding residual stresses in nozzle of nuclear power plants using finite element method

Energy Technology Data Exchange (ETDEWEB)

Kim, Wan Jae; Lee, Kyoung Soo; Kim, Tae Ryong [Korea Electric Power Research Institute, Daejeon (Korea, Republic of); Song, Tae Kwang [Korea Univ., Seoul (Korea, Republic of)

2008-07-01

Distribution of welding residual stresses are mainly characterized by degrees and frequencies of thermal loads applied to materials. However, other effects as component size and clamping condition can also affect stress distributions to a certain extent thus careful manipulation of these parameters based on clear understanding of how they affect residual stresses distributions and why can be additional measure to mitigate residual stresses. This paper discusses aforementioned issues for the case of safety and relief nozzle in nuclear power plant through finite element analysis.

Mass estimation of loose parts in nuclear power plant based on multiple regression

International Nuclear Information System (INIS)

He, Yuanfeng; Cao, Yanlong; Yang, Jiangxin; Gan, Chunbiao

2012-01-01

According to the application of the Hilbert–Huang transform to the non-stationary signal and the relation between the mass of loose parts in nuclear power plant and corresponding frequency content, a new method for loose part mass estimation based on the marginal Hilbert–Huang spectrum (MHS) and multiple regression is proposed in this paper. The frequency spectrum of a loose part in a nuclear power plant can be expressed by the MHS. The multiple regression model that is constructed by the MHS feature of the impact signals for mass estimation is used to predict the unknown masses of a loose part. A simulated experiment verified that the method is feasible and the errors of the results are acceptable. (paper)

Sensitivity studies for the main r process: nuclear masses

Directory of Open Access Journals (Sweden)

A. Aprahamian

2014-02-01

Full Text Available The site of the rapid neutron capture process (r process is one of the open challenges in all of physics today. The r process is thought to be responsible for the creation of more than half of all elements beyond iron. The scientific challenges to understanding the origin of the heavy elements beyond iron lie in both the uncertainties associated with astrophysical conditions that are needed to allow an r process to occur and a vast lack of knowledge about the properties of nuclei far from stability. One way is to disentangle the nuclear and astrophysical components of the question. On the nuclear physics side, there is great global competition to access and measure the most exotic nuclei that existing facilities can reach, while simultaneously building new, more powerful accelerators to make even more exotic nuclei. On the astrophysics side, various astrophysical scenarios for the production of the heaviest elements have been proposed but open questions remain. This paper reports on a sensitivity study of the r process to determine the most crucial nuclear masses to measure using an r-process simulation code, several mass models (FRDM, Duflo-Zuker, and HFB-21, and three potential astrophysical scenarios.

Approximate Approaches to the One-Dimensional Finite Potential Well

Science.gov (United States)

Singh, Shilpi; Pathak, Praveen; Singh, Vijay A.

2011-01-01

The one-dimensional finite well is a textbook problem. We propose approximate approaches to obtain the energy levels of the well. The finite well is also encountered in semiconductor heterostructures where the carrier mass inside the well (m[subscript i]) is taken to be distinct from mass outside (m[subscript o]). A relevant parameter is the mass…

Mass shift of σ-meson in nuclear matter

Indian Academy of Sciences (India)

Mass shift of σ-meson in nuclear matter. J R MORONES-IBARRA1, MÓNICA MENCHACA MACIEL1,∗. ,. AYAX SANTOS-GUEVARA2 and FELIPE ROBLEDO PADILLA1. 1Facultad de Ciencias Físico-Matemáticas, Universidad Autónoma de Nuevo León, UANL,. Av. Universidad S/N Ciudad Universitaria, San Nicolás de los ...

Soil-structure interaction in nuclear power plants: a comparison of methods

International Nuclear Information System (INIS)

Wight, L.H.

1976-06-01

We performed an extensive parametric survey to analyze the differences between two methods of calculating soil-structure interaction. One method involves discretizing the soil-structure system and solving for the complete response with the LUSH computer code. The other method solves for the lumped mass structural response with Whitman soil springs. Twelve soil-structure interaction problems are solved by each of these methods. Representative results are presented and discussed. The debate within the nuclear industry in the United States over the relative merits of various methods of calculating soil-structure interaction has intensified over the last three years. The debate is largely the result of the U.S. Nuclear Regulatory Commission's position generally favoring the finite element approach. Certain sectors of the industry claim that this ruling is without technical basis, that it requires unnecessary expense, and that it inhibits the judgment of the analyst. We have addressed each of these points through lumped mass and finite element calculations on a set of twelve soil-structure interaction problems. The results of these calculations indicate some of the consequences of the choice of method

Nuclear research with heavy ions

International Nuclear Information System (INIS)

Kaplan, M.

1991-08-01

This report discusses the following topics: Asymmetric fission of 149 Tb* from the finite-range, rotating-liquid-drop model: mean total kinetic energies for binary fragmentation; charged-particle evaporation from hot composite nuclei: evidence over a broad Z range for distortions from cold nuclear profiles; the role of reversed kinematics and double kinematic solutions in nuclear reactions studies; production of intermediate-mass-fragments in the reaction 98 Mo + 51 V at an excitation energy E* = 224-MeV; emission of light charged particles in the reaction 344-MeV 28 Si + 121 Sb; continued developments of the statistical evaporation code LILITA N90; and planning for heavy-ion-collision studies at very high energies: the STAR collaboration at RHIC

Bibliography for finite elements. [2200 references

Energy Technology Data Exchange (ETDEWEB)

Whiteman, J R [comp.

1975-01-01

This bibliography cites almost all of the significant papers on advances in the mathematical theory of finite elements. Reported are applications in aeronautical, civil, mechanical, nautical and nuclear engineering. Such topics as classical analysis, functional analysis, approximation theory, fluids, and diffusion are covered. Over 2200 references to publications up to the end of 1974 are included. Publications are listed alphabetically by author and also by keywords. In addition, finite element packages are listed.

Photon propagators at finite temperature

International Nuclear Information System (INIS)

Yee, J.H.

1982-07-01

We have used the real time formalism to compute the one-loop finite temperature corrections to the photon self energies in spinor and scalar QED. We show that, for a real photon, only the transverse components develop the temperature-dependent masses, while, for an external static electromagnetic field applied to the finite temperature system, only the static electric field is screened by thermal fluctuations. After showing how to compute systematically the imaginary parts of the finite temperature Green functions, we have attempted to give a microscopic interpretation of the imaginary parts of the self energies. (author)

Characterization of Nuclear Materials Using Complex of Non-Destructive and Mass-Spectroscopy Methods of Measurements

International Nuclear Information System (INIS)

Gorbunova, A.; Kramchaninov, A.

2015-01-01

Information and Analytical Centre for nuclear materials investigations was established in Russian Federation in the February 2 of 2009 by ROSATOM State Atomic Energy Corporation (the order #80). Its purpose is in preventing unauthorized access to nuclear materials and excluding their illicit traffic. Information and Analytical Centre includes analytical laboratory to provide composition and properties of nuclear materials of unknown origin for their identification. According to Regulation the Centre deals with: · identification of nuclear materials of unknown origin to provide information about their composition and properties; · arbitration analyzes of nuclear materials; · comprehensive research of nuclear and radioactive materials for developing techniques characterization of materials; · interlaboratory measurements; · measurements for control and accounting; · confirmatory measurements. Complex of non-destructive and mass-spectroscopy techniques was developed for the measurements. The complex consists of: · gamma-ray techniques on the base of MGAU, MGA and FRAM codes for uranium and plutonium isotopic composition; · gravimetrical technique with gamma-spectroscopy in addition for uranium content; · calorimetric technique for plutonium mass; · neutron multiplicity technique for plutonium mass; · measurement technique on the base of mass-spectroscopy for uranium isotopic composition; · measurement technique on the base of mass-spectroscopy for metallic impurities. Complex satisfies the state regulation requirements of ensuring the uniformity of measurements including the Russian Federation Federal Law on Ensuring the Uniformity of Measurements #102-FZ, Interstate Standard GOST R ISO/IEC 17025-2006, National Standards of Russian Federation GOST R 8.563-2009, GOST R 8.703-2010, Federal Regulations NRB-99/2009, OSPORB 99/2010. Created complex is provided in reference materials, equipment end certificated techniques. The complex is included in accredited

Atomic mass and characteristic constant of nuclear ground state (CENPL.MCC). Pt. 1

International Nuclear Information System (INIS)

Su Zongdi; Ma Lizhen; Zhou Chunmei; Ge Zhigang

1994-01-01

Atomic mass and characteristic constants for nuclear ground states are basic data for nuclear physics, and necessary ones for basic researches, theoretical calculations, as well as many applied researches. The atomic mass of exotic nuclei quite far from the valley stability are also very important for astrophysics researches. The above-requirement is paid attention to in our setting up this file. The recent and as many as possible data (such as the half-lives of the new nuclides 202 Pt, 208 Hg and 185 Hf and the mass excess of 199 Ir, which were produced and distinguished by Chinese scientists) have been collected, and put into the computer-based data file in brief table format. (1 fig.)

Computation with Inverse States in a Finite Field FPα: The Muon Neutrino Mass, the Unified Strong-Electroweak Coupling Constant, and the Higgs Mass

International Nuclear Information System (INIS)

Dai, Yang; Borisov, Alexey B.; Boyer, Keith; Rhodes, Charles K.

2000-01-01

The construction of inverse states in a finite field F P α enables the organization of the mass scale with fundamental octets in an eight-dimensional index space that identifies particle states with residue class designations. Conformance with both CPT invariance and the concept of supersymmetry follows as a direct consequence of this formulation. Based on two parameters (P α and g α ) that are anchored on a concordance of physical data, this treatment leads to (1) a prospective mass for the muon neutrino of approximately27.68 meV, (2) a value of the unified strong-electroweak coupling constant α* = (34.26) -1 that is physically defined by the ratio of the electron neutrino and muon neutrino masses, and (3) a see-saw congruence connecting the Higgs, the electron neutrino, and the muon neutrino masses. Specific evaluation of the masses of the corresponding supersymmetric Higgs pair reveals that both particles are superheavy (> 10 18 GeV). No renormalization of the Higgs masses is introduced, since the calculational procedure yielding their magnitudes is intrinsically divergence-free. Further, the Higgs fulfills its conjectured role through the see-saw relation as the particle defining the origin of all particle masses, since the electron and muon neutrino systems, together with their supersymmetric partners, are the generators of the mass scale and establish the corresponding index space. Finally, since the computation of the Higgs masses is entirely determined by the modulus of the field P α , which is fully defined by the large-scale parameters of the universe through the value of the universal gravitational constant G and the requirement for perfect flatness (Omega = 1.0), the see-saw congruence fuses the concepts of mass and space and creates a new unified archetype

Nuclear reactions of high energy deuterons with medium mass targets

International Nuclear Information System (INIS)

Numajiri, Masaharu; Miura, Taichi; Oki, Yuichi

1994-01-01

Formation cross sections of product nuclides in the nuclear reactions of medium mass targets by 10 GeV deuterons were measured with a gamma-ray spectroscopy. The measured data were compared with the cross sections of 12 GeV protons. (author)

Finite top-mass effects in gluon-induced Higgs production with a jet-veto at NNLO

Energy Technology Data Exchange (ETDEWEB)

Neumann, Tobias [Universitaet Wuppertal (Germany); Wiesemann, Marius [Universitaet Zuerich (Switzerland)

2015-07-01

Effects from a finite top quark mass on the H+n-jet cross section through gluon fusion are studied for n = 0/n ≥ 1 at NNLO/NLO QCD. For this purpose, sub-leading terms in 1/m{sub t} are calculated. We show that the asymptotic expansion of the jet-vetoed cross section at NNLO is very well behaved and that the heavy-top approximation is valid at the five permille level up to jet-veto cuts of 300 GeV. For the inclusive Higgs+jet rate, we introduce a matching procedure that allows for a reliable prediction of the top-mass effects using the expansion in 1/m{sub t}. The quality of the effective field theory to evaluate differential K-factors for the distribution of the hardest jet is found to be better than 1-2% as long as the transverse momentum of the jet is integrated out or remains below about 150 GeV.

FEHM, Finite Element Heat and Mass Transfer Code

International Nuclear Information System (INIS)

Zyvoloski, G.A.

2002-01-01

1 - Description of program or function: FEHM is a numerical simulation code for subsurface transport processes. It models 3-D, time-dependent, multiphase, multicomponent, non-isothermal, reactive flow through porous and fractured media. It can accurately represent complex 3-D geologic media and structures and their effects on subsurface flow and transport. Its capabilities include flow of gas, water, and heat; flow of air, water, and heat; multiple chemically reactive and sorbing tracers; finite element/finite volume formulation; coupled stress module; saturated and unsaturated media; and double porosity and double porosity/double permeability capabilities. 2 - Methods: FEHM uses a preconditioned conjugate gradient solution of coupled linear equations and a fully implicit, fully coupled Newton Raphson solution of nonlinear equations. It has the capability of simulating transport using either a advection/diffusion solution or a particle tracking method. 3 - Restriction on the complexity of the problem: Disk space and machine memory are the only limitations

Finiteness and GUTs

International Nuclear Information System (INIS)

Kapetanakis, D.; Mondragon, M.

1993-01-01

It is shown how to obtain phenomenologically viable SU(5) unified models which are finite to all orders before the spontaneous symmetry breaking. A very interesting feature of the models with three families is that they predict the top quark mass to be around 178 GeV. 16 refs

Heat and mass transfer and hydrodynamics in two-phase flows in nuclear power plants

International Nuclear Information System (INIS)

Styrikovich, M.A.; Polonskii, V.S.; Tsiklauri, G.V.

1986-01-01

This book examines nuclear power plant equipment from the point of view of heat and mass transfer and the behavior of impurities contained in water and in steam, with reference to real water regimes of nuclear power plants. The transfer processes of equipment are considered. Heat and mass transfer are analyzed in the pre-crisis regions of steam-generating passages with non-permeable surfaces, and in capillary-porous structures. Attention is given to forced convection boiling crises and top post-DNB heat transfer. Data on two-phase hydrodynamics in straight and curved channels are correlated and safety aspects of nuclear power plants are discussed

Relativistic finite-temperature Thomas-Fermi model

Science.gov (United States)

Faussurier, Gérald

2017-11-01

We investigate the relativistic finite-temperature Thomas-Fermi model, which has been proposed recently in an astrophysical context. Assuming a constant distribution of protons inside the nucleus of finite size avoids severe divergence of the electron density with respect to a point-like nucleus. A formula for the nuclear radius is chosen to treat any element. The relativistic finite-temperature Thomas-Fermi model matches the two asymptotic regimes, i.e., the non-relativistic and the ultra-relativistic finite-temperature Thomas-Fermi models. The equation of state is considered in detail. For each version of the finite-temperature Thomas-Fermi model, the pressure, the kinetic energy, and the entropy are calculated. The internal energy and free energy are also considered. The thermodynamic consistency of the three models is considered by working from the free energy. The virial question is also studied in the three cases as well as the relationship with the density functional theory. The relativistic finite-temperature Thomas-Fermi model is far more involved than the non-relativistic and ultra-relativistic finite-temperature Thomas-Fermi models that are very close to each other from a mathematical point of view.

Combating the terrorist use of mass destruction weapons, particularly nuclear weapons

International Nuclear Information System (INIS)

Barakat, M.

2008-01-01

The risks of mass destruction weapons vary and also forms of damages resulting therefrom. While the effects of nuclear weapons are focused, sudden and comprehensive, the chemical weapons have limited impacts relatively unless used intensively severe prejudice to the element of surprise, and thus impaired the efficacy of their influences,especially that they affect exceptionally the individuals in the area of injury and biological weapons do not announce themselves except through their effect that appears later than the time of use as they affect exceptionally the organisms in the area of injury.The mass destruction weapons have turned from being a purely military means in the early twentieth century and have now become the means of violence against governments and countries that they should prepare themselves for and respond in ways of successful and effective countermeasures. Despite the fact that the acquisition of mass destruction weapons can be considered as a priority objective, which terrorist groups and organizations steadily seek but their accessibility is flanked by a lot of difficulties. Addressing the risk of further spread of nuclear weapons, and especially after doubling the power of those high-risk weapons, the international community has an approach to take a number of arrangements that complement each other to control and resist nuclear proliferation, either for the states or for terrorist groups.

Extrapolations of nuclear binding energies from new linear mass relations

DEFF Research Database (Denmark)

Hove, D.; Jensen, A. S.; Riisager, K.

2013-01-01

We present a method to extrapolate nuclear binding energies from known values for neighboring nuclei. We select four specific mass relations constructed to eliminate smooth variation of the binding energy as function nucleon numbers. The fast odd-even variations are avoided by comparing nuclei...

Finite Volumes for Complex Applications VII

CERN Document Server

Ohlberger, Mario; Rohde, Christian

2014-01-01

The methods considered in the 7th conference on "Finite Volumes for Complex Applications" (Berlin, June 2014) have properties which offer distinct advantages for a number of applications. The second volume of the proceedings covers reviewed contributions reporting successful applications in the fields of fluid dynamics, magnetohydrodynamics, structural analysis, nuclear physics, semiconductor theory and other topics. The finite volume method in its various forms is a space discretization technique for partial differential equations based on the fundamental physical principle of conservation. Recent decades have brought significant success in the theoretical understanding of the method. Many finite volume methods preserve further qualitative or asymptotic properties, including maximum principles, dissipativity, monotone decay of free energy, and asymptotic stability. Due to these properties, finite volume methods belong to the wider class of compatible discretization methods, which preserve qualitative propert...

Characterization of resonances using finite size effects

International Nuclear Information System (INIS)

Pozsgay, B.; Takacs, G.

2006-01-01

We develop methods to extract resonance widths from finite volume spectra of (1+1)-dimensional quantum field theories. Our two methods are based on Luscher's description of finite size corrections, and are dubbed the Breit-Wigner and the improved ''mini-Hamiltonian'' method, respectively. We establish a consistent framework for the finite volume description of sufficiently narrow resonances that takes into account the finite size corrections and mass shifts properly. Using predictions from form factor perturbation theory, we test the two methods against finite size data from truncated conformal space approach, and find excellent agreement which confirms both the theoretical framework and the numerical validity of the methods. Although our investigation is carried out in 1+1 dimensions, the extension to physical 3+1 space-time dimensions appears straightforward, given sufficiently accurate finite volume spectra

Impact of nuclear 'pasta' on neutrino transport in collapsing stellar cores

International Nuclear Information System (INIS)

Sonoda, Hidetaka; Watanabe, Gentaro; Sato, Katsuhiko; Takiwaki, Tomoya; Yasuoka, Kenji; Ebisuzaki, Toshikazu

2007-01-01

Nuclear 'pasta', nonspherical nuclei in dense matter, is predicted to occur in collapsing supernova cores. We show how pasta phases affect the neutrino transport cross section via weak neutral current using several nuclear models. This is the first calculation of the neutrino opacity of the phases with rod-like and slab-like nuclei taking account of finite temperature effects, which are well described by the quantum molecular dynamics. We also show that pasta phases can occupy 10-20% of the mass of supernova cores in the later stage of the collapse

Proposal for the determination of nuclear masses by high-precision spectroscopy of Rydberg states

International Nuclear Information System (INIS)

Wundt, B J; Jentschura, U D

2010-01-01

The theoretical treatment of Rydberg states in one-electron ions is facilitated by the virtual absence of the nuclear-size correction, and fundamental constants like the Rydberg constant may be in the reach of planned high-precision spectroscopic experiments. The dominant nuclear effect that shifts transition energies among Rydberg states therefore is due to the nuclear mass. As a consequence, spectroscopic measurements of Rydberg transitions can be used in order to precisely deduce nuclear masses. A possible application of this approach to hydrogen and deuterium, and hydrogen-like lithium and carbon is explored in detail. In order to complete the analysis, numerical and analytic calculations of the quantum electrodynamic self-energy remainder function for states with principal quantum number n = 5, ..., 8 and with angular momentum l = n - 1 and l = n - 2 are described (j = l +- 1/2).

Proposal for the determination of nuclear masses by high-precision spectroscopy of Rydberg states

Energy Technology Data Exchange (ETDEWEB)

Wundt, B J; Jentschura, U D [Department of Physics, Missouri University of Science and Technology, Rolla, MO 65409-0640 (United States)

2010-06-14

The theoretical treatment of Rydberg states in one-electron ions is facilitated by the virtual absence of the nuclear-size correction, and fundamental constants like the Rydberg constant may be in the reach of planned high-precision spectroscopic experiments. The dominant nuclear effect that shifts transition energies among Rydberg states therefore is due to the nuclear mass. As a consequence, spectroscopic measurements of Rydberg transitions can be used in order to precisely deduce nuclear masses. A possible application of this approach to hydrogen and deuterium, and hydrogen-like lithium and carbon is explored in detail. In order to complete the analysis, numerical and analytic calculations of the quantum electrodynamic self-energy remainder function for states with principal quantum number n = 5, ..., 8 and with angular momentum l = n - 1 and l = n - 2 are described (j = l {+-} 1/2).

Contribution of Italy to the activities on intercomparison of analysis methods for seismically isolated nuclear structures: Finite element analysis of lead rubber bearings

International Nuclear Information System (INIS)

Dusi, A.; Forni, M.; Martelli, A.

1998-01-01

This paper presents a summary of the results of nonlinear Finite Element (FE) analyses carried out by ENEL-Ricerca, Hydraulic and Structural Centre and ENEA-ERG-SIEC-SISM, on Lead Rubber Bearings (LRBs). Activities were carried out in the framework of the four years' Coordinated Research Programme (CRP) of the International Atomic Energy Agency (IAEA) on I ntercomparison of Analysis Methods for Seismically Isolated Nuclear Structures . The bearing Finite Element Models (FEMs) are validated through comparisons of the numerical results with experimental test data. The reliability of FEMs for simulating the behaviour of rubber bearings is presented and discussed. (author)

Double beta decays and related subjects for particle and nuclear physics

International Nuclear Information System (INIS)

Ejiri, Hiroyasu

1991-01-01

Present status and some perspectives in 1990's are briefly given on double beta decays and related subjects. Subjects discussed are as follows I) Double beta decays without neutrinos, which require lepton number non-conservations and finite neutrino mass. II) Double beta decays followed by two neutrinos. III) Double weak processes with strangeness change ΔS = 2, leading to the H particle with 6 quarks of ss uu dd. IV) Charge non-conservation and electron decays. These are very rare nuclear processes studied by Ultra RAre-process NUclear Spectroscopy (URANUS). It is shown that URANUS is an important detector frontier of non-accelerator nuclear physics in 1990's. (orig.)

Finite temperature system of strongly interacting baryons

International Nuclear Information System (INIS)

Bowers, R.L.; Gleeson, A.M.; Pedigo, R.D.; Wheeler, J.W.

1976-07-01

A fully relativistic finite temperature many body theory is constructed and used to examine the bulk properties of a system of strongly interacting baryons. The strong interactions are described by a two parameter phenomenological model fit to a simple description of nuclear matter at T = 0. The zero temperature equation of state for such a system which has already been discussed in the literature was developed to give a realistic description of nuclear matter. The model presented here is the exact finite temperature extension of that model. The effect of the inclusion of baryon pairs for T greater than or equal to 2mc 2 /k is discussed in detail. The phase transition identified with nuclear matter vanishes for system temperatures in excess of T/sub C/ = 1.034 x 10 11 0 K. All values of epsilon (P,T) correspond to systems that are causal in the sense that the locally determined speed of sound never exceeds the speed of light

Finite temperature system of strongly interacting baryons

Energy Technology Data Exchange (ETDEWEB)

Bowers, R.L.; Gleeson, A.M.; Pedigo, R.D.; Wheeler, J.W.

1976-07-01

A fully relativistic finite temperature many body theory is constructed and used to examine the bulk properties of a system of strongly interacting baryons. The strong interactions are described by a two parameter phenomenological model fit to a simple description of nuclear matter at T = 0. The zero temperature equation of state for such a system which has already been discussed in the literature was developed to give a realistic description of nuclear matter. The model presented here is the exact finite temperature extension of that model. The effect of the inclusion of baryon pairs for T greater than or equal to 2mc/sup 2//k is discussed in detail. The phase transition identified with nuclear matter vanishes for system temperatures in excess of T/sub C/ = 1.034 x 10/sup 11/ /sup 0/K. All values of epsilon (P,T) correspond to systems that are causal in the sense that the locally determined speed of sound never exceeds the speed of light.

The delay function in finite difference models for nuclear channels thermo-hydraulic transients

International Nuclear Information System (INIS)

Agazzi, A.

1977-01-01

The study of the thermo-hydraulic transients in a nuclear reactor core often requires a bi- or tri-dimensional mathematical simulation of a reactor channel. The equations involved are generally solved by means of finite-difference methods. The determination of the spatial mesh-width and the time interval is strongly conditioned by the necessity of a good accuracy in the description of the delay function which defines the transfer of thermal perturbations along the cooling channel. In this paper the effects of both space and time discretization on the delay function are considered and for the classical cases of inlet temperature step and ramp universal functions and diagrams are given in order to make possible the determination of optimal spatial mesh-width and time interval, once the requested accuracy of the model is fixed in advance

Accelerator Mass Spectrometry with 15 UD pelletron at the Nuclear Science Centre, New Delhi

International Nuclear Information System (INIS)

Datta, S.K.

1997-01-01

The 15 UD Pelletron machine is widely used to carry on investigations in a variety of disciplines like nuclear physics, materials science, radiobiology etc. Accelerator Mass Spectrometry studies with 15 UD pelletron machine at Nuclear Science Centre are elaborated

Alterations in the nuclear matrix protein mass correlate with heat-induced inhibition of DNA single-strand-break repair

International Nuclear Information System (INIS)

Warters, R.L.; Brizgys, L.M.; Lyons, B.W.

1987-01-01

The total protein mass co-isolating with the nuclear matrix or nucleoid from Chinese hamster ovary (CHO) cells was observed to increase in heated cells as a function of increasing exposure temperature between 43 0 C and 45 0 C or of exposure time at any temperature. The sedimentation distance of the CHO cell nucleoid in sucrose gradients increased with increasing exposure time at 45 0 C. Both these nuclear alterations correlated in a log-linear manner with heat-induced inhibition of DNA strand break repair. A two-fold threshold increase in nuclear matrix protein mass preceded any substantial inhibition of repair of DNA single-strand breaks. When preheated cells were incubated at 37 0 C the nuclear matrix protein mass and nucleoid sedimentation recovered with a half-time of about 5 h, while DNA single-strand-break repair recovered with a half-time of about 2 h. When preheated cells were placed at 41 0 C a further increase was observed in the nuclear matrix protein mass and the half-time of DNA strand break repair, while nucleoid sedimentation recovered toward control values. These results implicate alterations in the protein mass of the nuclear matrix in heat-induced inhibition of repair of DNA single-strand breaks. (author)

Finite size scaling and lattice gauge theory

International Nuclear Information System (INIS)

Berg, B.A.

1986-01-01

Finite size (Fisher) scaling is investigated for four dimensional SU(2) and SU(3) lattice gauge theories without quarks. It allows to disentangle violations of (asymptotic) scaling and finite volume corrections. Mass spectrum, string tension, deconfinement temperature and lattice β-function are considered. For appropriate volumes, Monte Carlo investigations seem to be able to control the finite volume continuum limit. Contact is made with Luescher's small volume expansion and possibly also with the asymptotic large volume behavior. 41 refs., 19 figs

Isotopic abundance measurements on solid nuclear-type samples by glow discharge mass spectrometry

International Nuclear Information System (INIS)

Betti, M.; Rasmussen, G.; Koch, L.

1996-01-01

A double-focusing glow discharge mass spectrometer (GDMS) installed in a glovebox for nuclear sample screening has been employed for isotopic measurements. Isotopic compositions of zirconium, silicon, lithium, boron, uranium and plutonium which are elements of nuclear concern have been determined. Interferences arising from the matrix sample and the discharge gas (Ar) for each of these elements are discussed. The GDMS results are compared with those from thermal ionization mass spectrometry (TIMS). For boron and lithium at μg/g-ng/g levels, the two methods gave results in good agreement. In samples containing uranium the isotopic composition obtained by GDMS was in agreement with those from TIMS independently of the enrichment. Attempts for the determination of plutonium isotopic composition were also made. In this case, due to the interferences of uranium at mass 238 and americium at mass 241, the GDMS raw data are complementary with those values obtained from physical non-destructive techniques. (orig.). With 2 figs., 4 tabs

Ablation and deceleration of mass-driver launched projectiles for space disposal of nuclear wastes

International Nuclear Information System (INIS)

Park, C.; Bowen, S.W.

1981-01-01

The energy cost of launching a projectile containing nuclear waste is two orders of magnitude lower with a mass driver than with a typical rocket system. A mass driver scheme will be feasible, however, only if ablation and deceleration are within certain tolerable limits. It is shown that if a hemisphere-cylinder-shaped projectile protected thermally with a graphite nose is launched vertically to attain a velocity of 17 km/sec at an altitude of 40 km, the mass loss from ablation during atmospheric flight will be less than 0.1 ton, provided the radius of the projectile is under 20 cm and the projectile's mass is of the order of 1 ton. The velocity loss from drag will vary from 0.4 to 30 km/sec, depending on the mass and radius of the projectile, the smaller velocity loss corresponding to large mass and small radius. Ablation is always within a tolerable range for schemes using a mass driver launcher to dispose of nuclear wastes outside the solar system. Deceleration can also be held in the tolerable range if the mass and diameter of the projectile are properly chosen

Measures with locally finite support and spectrum.

Science.gov (United States)

Meyer, Yves F

2016-03-22

The goal of this paper is the construction of measures μ on R(n)enjoying three conflicting but fortunately compatible properties: (i) μ is a sum of weighted Dirac masses on a locally finite set, (ii) the Fourier transform μ f μ is also a sum of weighted Dirac masses on a locally finite set, and (iii) μ is not a generalized Dirac comb. We give surprisingly simple examples of such measures. These unexpected patterns strongly differ from quasicrystals, they provide us with unusual Poisson's formulas, and they might give us an unconventional insight into aperiodic order.

Characterisation of nuclear fuel samples by quadrupole and multi-collector inductively coupled plasma mass spectrometry

International Nuclear Information System (INIS)

Wernli, Beath; Guenther-Leopold, Ines; Kobler Waldis, Judith; Kopajtic, Zlatan

2003-01-01

The characterisation of nuclear fuel cycle materials for trace and minor metallic constituents is of great interest for the nuclear industry and safeguard officials. The main objective of various international programmes dealing with postirradiation examinations is to improve the knowledge of the inventories of actinides, fission and spallation products in spent nuclear fuels. The low detection limits for a large number of elements combined with the ability to analyse the isotopic composition of the elements have established inductively coupled plasma mass spectrometry (ICP-MS) as a powerful multi-element technique in diverse analytical applications for the characterisation of nuclear materials. Because numerous isobaric overlaps restrict the direct determination of many fission products by mass spectrometry, extensive chemical separations are required for these elements. In order to simplify this sample preparation procedure, a high performance liquid chromatography system (HPLC) was online coupled to the mass spectrometer. Since about 10 years a quadrupole based ICP-MS (Q-ICP-MS) combined with an HPLC is used within the Hot Laboratory of the Paul Scherrer Institut for different applications on nuclear fuel samples. Since May 2003 also a new multi-collector ICP-MS (MC-ICP-MS) is used for the mass spectrometric characterisation of nuclear fuel samples, especially for the precise determination of the isotopic vectors of fission products and actinides. Therefore, two complementary analytical systems are now available in the group of 'Isotope and Wet Analytical Chemistry'. A comparison of the analytical performance of both systems (with and without an online coupled HPLC system) for the determination of the isotopic composition and the elemental concentration of different nuclides in nuclear fuel samples, the advantages and limitations of both techniques, the accuracy and precision of the results and typical applications for both methods will be discussed in the

A finite range pairing force for density functional theory in superfluid nuclei

International Nuclear Information System (INIS)

Tian, Y.; Ma, Z.Y.; Ring, P.

2009-01-01

The problem of pairing in the 1 S 0 channel of finite nuclei is revisited. In nuclear matter forces of separable form can be adjusted to the bare nuclear force, to any phenomenological pairing interaction such as the Gogny force or to exact solutions of the gap equation. In finite nuclei, because of translational invariance, such forces are no longer separable. Using well-known techniques of Talmi and Moshinsky we expand the matrix elements in a series of separable terms, which converges quickly preserving translational invariance and finite range. In this way the complicated problem of a cut-off at large momenta or energies inherent in other separable or zero range pairing forces is avoided. Applications in the framework of the relativistic Hartree-Bogoliubov approach show that the pairing properties are depicted on almost the same footing as by the original pairing interaction not only in nuclear matter, but also in finite nuclei. This simple separable force can be easily applied for the investigation of pairing properties in nuclei far from stability as well as for further investigations going beyond mean field theory.

Derivation of binding energies on the basis of fundamental nuclear theory

International Nuclear Information System (INIS)

Kouki, Tuomo.

1975-10-01

An attempt to assess the degree of consistency between the underlying ideas of two different approaches to nuclear energy relations is described. The fundamental approach in the form of density dependent Hartree-Fock theory, as well as the method of renormalizing shell model energies have both met with fair success. Whereas the former method is based on nuclear matter theory, the latter's central idea is to combine shell structure with an average liquid drop behaviour. The shell smoothing procedure employed there has been subject to intense theoretical study. Only little attention has been paid to the liquid drop aspect of the method. It is purposed to derive the liquid drop mass formula by means of a model force fitted to results of some nuclear matter calculations. Moreover, the force is tested by applying it to finite nuclei. Because of this, the present work could also be regarded as an attempt to find a very direct way of relating nuclear matter properties to those of finite nuclei. As the results in this respect are worse than expected, we conclude with a discussion of possible directions of improvement. (author)

: Nuclear Spirals and Mass Accretion to Supermassive Black Holes in Weakly-Barred Galaxies

Science.gov (United States)

Kim, Woong-Tae; Elmegreen, Bruce

2018-01-01

Disk galaxies, especially barred-spiral galaxies, abound with rings and spirals in their nuclear regions. Nuclear spirals existing even in weakly barred galaxies are thought to channel gas inflows to supermassive black holes residing at the centers. We use high-resolution hydrodynamic simulations to study the properties of nuclear gas spirals driven by weak bar-like or oval potentials. The amplitude of the spirals increases toward the center by a geometric effect, readily developing into shocks at small radii even for very weak potentials. The shape of the spirals and shocks depends rather sensitively on the background shear. When shear is low, the nuclear spirals are loosely wound and the shocks are almost straight, resulting in large mass inflows toward the center. When shear is high, on the other hand, the spirals are tightly wound and the shocks are oblique, forming a circumnuclear disk through which gas flows inward at a relatively lower rate. The induced mass inflow rates are enough to power black hole accretion in various types of Seyfert galaxies.

Charm mass corrections to the bottomonium mass spectrum

International Nuclear Information System (INIS)

Ebert, D.; Faustov, R. N.; Galkin, V. O.

2002-01-01

The one-loop corrections to the bottomonium mass spectrum due to the finite charm mass are evaluated in the framework of the relativistic quark model. The obtained corrections are compared with the results of perturbative QCD

A quadrupole mass spectrometer system for nuclear safeguards applications

International Nuclear Information System (INIS)

Evans, P.J.

1987-12-01

An on-line enrichment monitor for nuclear safeguards-related surveillance of a pilot-scale gas centrifuge plant is described. This monitor utilises a quadrupole mass spectrometer to measure the isotopic composition of UF 6 in the feed and product gas streams. Details of the design and construction are given, and several difficulties are identified and discussed. Finally, the performance of this system is illustrated with typical results

The impact of global nuclear mass model uncertainties on r-process abundance predictions

Directory of Open Access Journals (Sweden)

Mumpower M.

2015-01-01

Full Text Available Rapid neutron capture or ‘r-process’ nucleosynthesis may be responsible for half the production of heavy elements above iron on the periodic table. Masses are one of the most important nuclear physics ingredients that go into calculations of r-process nucleosynthesis as they enter into the calculations of reaction rates, decay rates, branching ratios and Q-values. We explore the impact of uncertainties in three nuclear mass models on r-process abundances by performing global monte carlo simulations. We show that root-mean-square (rms errors of current mass models are large so that current r-process predictions are insufficient in predicting features found in solar residuals and in r-process enhanced metal poor stars. We conclude that the reduction of global rms errors below 100 keV will allow for more robust r-process predictions.

Finite-temperature mobility of a particle coupled to a fermionic environment

International Nuclear Information System (INIS)

Castella, H.; Zotos, X.

1996-01-01

We study numerically the finite-temperature and frequency mobility of a particle coupled by a local interaction to a system of spinless fermions in one dimension. We find that when the model is integrable (particle mass equal to the mass of fermions) the static mobility diverges. Further, an enhanced mobility is observed over a finite parameter range away from the integrable point. We present an analysis of the finite-temperature static mobility based on a random matrix theory description of the many-body Hamiltonian. copyright 1996 The American Physical Society

The management-retrieval code of the sub-library of atomic mass and characteristic constants for nuclear ground state

International Nuclear Information System (INIS)

Su Zongdi; Ma Lizhen

1994-01-01

The management code of the sub-library of atomic mass and characteristic constants for nuclear ground state (MCC) is used for displaying the basic information on the MCC sub-library on the screen, and retrieving the required data. The MCC data file contains the data of 4800 nuclides ranging from Z 0, A = 1 to Z = 122, A = 318. The MCC sub-library has been set up at Chinese Nuclear Data Center (CNDC), and has been used to provide the atomic masses and characteristic constants of nuclear ground states for the nuclear model calculation, nuclear data evaluations and other fields

The kinetic energy operator for distance-dependent effective nuclear masses: Derivation for a triatomic molecule.

Science.gov (United States)

Khoma, Mykhaylo; Jaquet, Ralph

2017-09-21

The kinetic energy operator for triatomic molecules with coordinate or distance-dependent nuclear masses has been derived. By combination of the chain rule method and the analysis of infinitesimal variations of molecular coordinates, a simple and general technique for the construction of the kinetic energy operator has been proposed. The asymptotic properties of the Hamiltonian have been investigated with respect to the ratio of the electron and proton mass. We have demonstrated that an ad hoc introduction of distance (and direction) dependent nuclear masses in Cartesian coordinates preserves the total rotational invariance of the problem. With the help of Wigner rotation functions, an effective Hamiltonian for nuclear motion can be derived. In the derivation, we have focused on the effective trinuclear Hamiltonian. All necessary matrix elements are given in closed analytical form. Preliminary results for the influence of non-adiabaticity on vibrational band origins are presented for H 3 + .

Nuclear technology: katulong sa pag-unlad ng masa [support for the progress of the masses

International Nuclear Information System (INIS)

1999-01-01

The topics discussed during the convention is the usefulness of nuclear science and technology in national development and to promote the beneficial uses of nuclear science and technology to support for the progress of the masses

Finite energy electroweak dyon

Energy Technology Data Exchange (ETDEWEB)

Kimm, Kyoungtae [Seoul National University, Faculty of Liberal Education, Seoul (Korea, Republic of); Yoon, J.H. [Konkuk University, Department of Physics, College of Natural Sciences, Seoul (Korea, Republic of); Cho, Y.M. [Konkuk University, Administration Building 310-4, Seoul (Korea, Republic of); Seoul National University, School of Physics and Astronomy, Seoul (Korea, Republic of)

2015-02-01

The latest MoEDAL experiment at LHC to detect the electroweak monopole makes the theoretical prediction of the monopole mass an urgent issue. We discuss three different ways to estimate the mass of the electroweak monopole. We first present the dimensional and scaling arguments which indicate the monopole mass to be around 4 to 10 TeV. To justify this we construct finite energy analytic dyon solutions which could be viewed as the regularized Cho-Maison dyon, modifying the coupling strength at short distance. Our result demonstrates that a genuine electroweak monopole whose mass scale is much smaller than the grand unification scale can exist, which can actually be detected at the present LHC. (orig.)

Software in windows for staple compounding system of microcomputer nuclear mass scale

International Nuclear Information System (INIS)

Wang Yanting; Zhang Yongming; Wang Yu; Jin Dongping

1998-01-01

The software exploited in windows for staple compounding system of microcomputer nuclear mass scale is described. The staple compounding system is briefly narrated. The software structure and its realizing method are given

Finite size effects of a pion matrix element

International Nuclear Information System (INIS)

Guagnelli, M.; Jansen, K.; Palombi, F.; Petronzio, R.; Shindler, A.; Wetzorke, I.

2004-01-01

We investigate finite size effects of the pion matrix element of the non-singlet, twist-2 operator corresponding to the average momentum of non-singlet quark densities. Using the quenched approximation, they come out to be surprisingly large when compared to the finite size effects of the pion mass. As a consequence, simulations of corresponding nucleon matrix elements could be affected by finite size effects even stronger which could lead to serious systematic uncertainties in their evaluation

Finite element analysis of degraded concrete structures - Workshop proceedings

International Nuclear Information System (INIS)

1999-09-01

This workshop is related to the finite element analysis of degraded concrete structures. It is composed of three sessions. The first session (which title is: the use of finite element analysis in safety assessments) comprises six papers which titles are: Historical Development of Concrete Finite Element Modeling for Safety Evaluation of Accident-Challenged and Aging Concrete Structures; Experience with Finite Element Methods for Safety Assessments in Switzerland; Stress State Analysis of the Ignalina NPP Confinement System; Prestressed Containment: Behaviour when Concrete Cracking is Modelled; Application of FEA for Design and Support of NPP Containment in Russia; Verification Problems of Nuclear Installations Safety Software of Strength Analysis (NISS SA). The second session (title: concrete containment structures under accident loads) comprises seven papers which titles are: Two Application Examples of Concrete Containment Structures under Accident Load Conditions Using Finite Element Analysis; What Kind of Prediction for Leak rates for Nuclear Power Plant Containments in Accidental Conditions; Influence of Different Hypotheses Used in Numerical Models for Concrete At Elevated Temperatures on the Predicted Behaviour of NPP Core Catchers Under Severe Accident Conditions; Observations on the Constitutive Modeling of Concrete Under Multi-Axial States at Elevated Temperatures; Analyses of a Reinforced Concrete Containment with Liner Corrosion Damage; Program of Containment Concrete Control During Operation for the Temelin Nuclear Power Plant; Static Limit Load of a Deteriorated Hyperbolic Cooling Tower. The third session (concrete structures under extreme environmental load) comprised five papers which titles are: Shear Transfer Mechanism of RC Plates After Cracking; Seismic Back Calculation of an Auxiliary Building of the Nuclear Power Plant Muehleberg, Switzerland; Seismic Behaviour of Slightly Reinforced Shear Wall Structures; FE Analysis of Degraded Concrete

Role of deformed shell effects on the mass asymmetry in nuclear fission of mercury isotopes

International Nuclear Information System (INIS)

Panebianco, Stefano; Sida, Jean-Luc; Goutte, Heloise; Lemaitre, Jean-Francois; Dubray, Noel; Hilaire, Stephane

2012-01-01

Until now, the mass asymmetry in the nuclear fission process has been understood in terms of the strong influence of the nuclear structure of the nascent fragments. Recently, a surprising asymmetric fission has been discovered in the light mercury region and has been interpreted as the result of the influence of the nuclear structure of the parent nucleus, totally discarding the influence of the fragments' structure. To assess the role of the fragment shell effects in the mass asymmetry in this particular region, a scission-point model, based on a full energy balance between the two nascent fragments, has been developed using one of the best theoretical descriptions of microscopic nuclear structure. As for actinides, this approach shows that the asymmetric splitting of the Hg-180 nucleus and the symmetric one of Hg-198 can be understood on the basis of only the microscopic nuclear structure of the fragments at scission. (authors)

Double-arm time-of-flight mass-spectrometer of nuclear fragments

International Nuclear Information System (INIS)

Ajvazian, G.M.; Astabatyan, R.A.

1995-01-01

A double-arm time-of-flight spectrometer of nuclear fragments for the investigation of heavy nuclei photofission in the intermediate energy range is described. The calibration results and working characteristics of the spectrometer, obtained using 252 Cf as a source of spontaneous fission, are presented. A mass resolution of σ m ∼2-3 a.m.u. was obtained within the registered fragments mass range of 80-160 a.m.u. The spectrometer was tested in the experiment on the investigation of 238 U nuclei fission by Bremsstahlung photons with Eγ max=1.75 GeV

Dense QCD in a Finite Volume

International Nuclear Information System (INIS)

Yamamoto, Naoki; Kanazawa, Takuya

2009-01-01

We study the properties of QCD at high baryon density in a finite volume where color superconductivity occurs. We derive exact sum rules for complex eigenvalues of the Dirac operator at a finite chemical potential, and show that the Dirac spectrum is directly related to the color superconducting gap Δ. Also, we find a characteristic signature of color superconductivity: an X-shaped spectrum of partition function zeros in the complex quark mass plane near the origin, reflecting the Z(2) L xZ(2) R symmetry of the diquark pairing. Our results are universal in the domain Δ -1 π -1 where L is the linear size of the system and m π is the pion mass at high density.

Heavy Scalar, Vector, and Axial-Vector Mesons in Hot and Dense Nuclear Medium

Directory of Open Access Journals (Sweden)

Arvind Kumar

2014-01-01

Full Text Available In this work we shall investigate the mass modifications of scalar mesons (D0; B0, vector mesons (D*; B*, and axial-vector mesons (D1; B1 at finite density and temperature of the nuclear medium. The above mesons are modified in the nuclear medium through the modification of quark and gluon condensates. We will find the medium modification of quark and gluon condensates within chiral SU(3 model through the medium modification of scalar-isoscalar fields σ and ζ at finite density and temperature. These medium modified quark and gluon condensates will further be used through QCD sum rules for the evaluation of in-medium properties of the above mentioned scalar, vector, and axial vector mesons. We will also discuss the effects of density and temperature of the nuclear medium on the scattering lengths of the above scalar, vector, and axial-vector mesons. The study of the medium modifications of the above mesons may be helpful for understanding their production rates in heavy-ion collision experiments. The results of present investigations of medium modifications of scalar, vector, and axial-vector mesons at finite density and temperature can be verified in the compressed baryonic matter (CBM experiment of FAIR facility at GSI, Germany.

Results in finite temperature quantum electrodynamics

International Nuclear Information System (INIS)

Down, D.M.

1985-01-01

First, three quantities of physical interest are calculated. The first two quantities are the self energy of the electron at order α and the self mass of the electron at order α 2 due to its interaction with a thermal bath of photons. The third quantity of physical interest is the thermal contribution to the self mass of the axion. Second, some formal developments are presented. First among these is the proof of an extension to the familiar optical theorem to cover processes taking place at finite temperature. Then an example of the application of the theorem is given for a simple field theory involving two types of scalar particles. The example illustrates that the relationship between the forward scattering amplitude and the total cross section is more complex at finite temperature than at zero temperature. Third, a method for calculating the wave function renormalization constant at finite temperature for an electron in a thermal bath of photons is presented. This method is compared with methods invented by other authors

Nonlinear finite element analysis of nuclear reinforced prestressed concrete containments up to ultimate load capacity

International Nuclear Information System (INIS)

Gupta, A.; Singh, R.K.; Kushwaha, H.S.; Mahajan, S.C.; Kakodkar, A.

1996-01-01

For safety evaluation of nuclear structures a finite element code ULCA (Ultimate Load Capacity Assessment) has been developed. Eight/nine noded isoparametric quadrilateral plate/shell element with reinforcement as a through thickness discrete but integral smeared layer of the element is presented to analyze reinforced and prestressed concrete structures. Various constitutive models such as crushing, cracking in tension, tension stiffening and rebar yielding are studied and effect of these parameters on the reserve strength of structures is brought out through a number of benchmark tests. A global model is used to analyze the prestressed concrete containment wall of a typical 220 MWe Pressurized Heavy Water Reactor (PHWR) up to its ultimate capacity. This demonstrates the adequacy of Indian PHWR containment design to withstand severe accident loads

Parquet theory of finite temperature boson systems

International Nuclear Information System (INIS)

He, H.W.

1992-01-01

In this dissertation, the author uses the parquet summation for the two-body vertex as the framework for a perturbation theory of finite-temperature homogeneous boson systems. The present formalism is a first step toward a full description of the thermodynamic behavior of a finite temperature boson system through parquet summation. The current approximation scheme focuses on a system below the Bose-Einstein condensation temperature and considers only the contribution from Bogoliubov excitations out of a boson condensate. Comparison with the finite temperature variational theory by Campbell et al. shows strong similarities between variational theory and the current theory. Numerical results from a 4 He system and a nuclear system are discussed

Uniformity measure for power-law mass spectrum in nuclear fragmentation

International Nuclear Information System (INIS)

Wislicki, W.

1992-11-01

Description is given in terms of the Renyi entropy and the uniformity for the canonical ensemble, the grand canonical ensemble and the power-law probability measures. The study is presented of the power-law spectra of cluster masses observed in nuclear interactions in the vicinity of the liquid-gas transition point. 6 figs., 1 tab., 15 refs. (author)

Nuclear moment of inertia and spin distribution of nuclear levels

International Nuclear Information System (INIS)

Alhassid, Y.; Fang, L.; Liu, S.; Bertsch, G.F.

2005-01-01

We introduce a simple model to calculate the nuclear moment of inertia at finite temperature. This moment of inertia describes the spin distribution of nuclear levels in the framework of the spin-cutoff model. Our model is based on a deformed single-particle Hamiltonian with pairing interaction and takes into account fluctuations in the pairing gap. We derive a formula for the moment of inertia at finite temperature that generalizes the Belyaev formula for zero temperature. We show that a number-parity projection explains the strong odd-even effects observed in shell model Monte Carlo studies of the nuclear moment of inertia in the iron region

Modified quark-meson coupling model for nuclear matter

International Nuclear Information System (INIS)

Jin, X.; Jennings, B.K.

1996-01-01

The quark-meson coupling model for nuclear matter, which describes nuclear matter as nonoverlapping MIT bags bound by the self-consistent exchange of scalar and vector mesons, is modified by introducing medium modification of the bag constant. We model the density dependence of the bag constant in two different ways: One invokes a direct coupling of the bag constant to the scalar meson field, and the other relates the bag constant to the in-medium nucleon mass. Both models feature a decreasing bag constant with increasing density. We find that when the bag constant is significantly reduced in nuclear medium with respect to its free-space value, large canceling isoscalar Lorentz scalar and vector potentials for the nucleon in nuclear matter emerge naturally. Such potentials are comparable to those suggested by relativistic nuclear phenomenology and finite-density QCD sum rules. This suggests that the reduction of bag constant in nuclear medium may play an important role in low- and medium-energy nuclear physics. copyright 1996 The American Physical Society

The finite temperature QCD phase transition and the thermodynamic equation of state. An investigation employing lattice QCD with Nf=2 twisted mass quarks

International Nuclear Information System (INIS)

Burger, Florian

2012-01-01

In this thesis we report about an investigation of the finite temperature crossover/phase transition of quantum chromodynamics and the evaluation of the thermodynamic equation of state. To this end the lattice method and the Wilson twisted mass discretisation of the quark action are used. This formulation is known to have an automatic improvement of lattice artifacts and thus an improved continuum limit behaviour. This work presents first robust results using this action for the non-vanishing temperature case. We investigate the chiral limit of the two flavour phase transition with several small values of the pion mass in order to address the open question of the order of the transition in the limit of vanishing quark mass. For the currently simulated pion masses in the range of 300 to 700 MeV we present evidence that the finite temperature transition is a crossover transition rather than a genuine phase transition. The chiral limit is investigated by comparing the scaling of the observed crossover temperature with the mass including several possible scenarios. Complementary to this approach the chiral condensate as the order parameter for the spontaneous breaking of chiral symmetry is analysed in comparison with the O(4) universal scaling function which characterises a second order transition. With respect to thermodynamics the equation of state is obtained from the trace anomaly employing the temperature integral method which provides the pressure and energy density in the crossover region. The continuum limit of the trace anomaly is studied by considering several values of N τ and the tree-level correction technique.

Nuclear assay of coal. Volume 6. Mass flow devices for coal handling

International Nuclear Information System (INIS)

Anon.

1979-01-01

The mass of coal entering the boiler per unit time is an essential parameter for determinig the total rate of heat input. The mass flow rate of coal on a conveyor belt is generally determined as a product of the instantaneous mass of material on a short section of the belt and the belt velocity. Belt loading could be measured by conventional transducers incorporating mechanical or electromechanical weighers or by gamma-ray attenuation gauge. This report reviews the state of the art in mass flow devices for coal handling. The various methods are compared and commented upon. Special design issues are discussed relative to incorporating a mass flow measuring device in a Continuous On-Line Nuclear Analysis of Coal (CONAC) system

Dense QCD in a Finite Volume

OpenAIRE

Yamamoto, Naoki; Kanazawa, Takuya

2009-01-01

We study the properties of QCD at high baryon density in a finite volume where color superconductivity occurs. We derive exact sum rules for complex eigenvalues of the Dirac operator at finite chemical potential, and show that the Dirac spectrum is directly related to the color superconducting gap $\\Delta$. Also, we find a characteristic signature of color superconductivity: an X-shaped spectrum of partition function zeros in the complex quark mass plane near the origin, reflecting the $Z(2)_...

φφ Back-to-Back Correlations in Finite Expanding Systems

International Nuclear Information System (INIS)

Padula, S. S.; Krein, G.; Hama, Y.; Panda, P. K.; Csoergo, T.

2006-01-01

Back-to-Back Correlations (BBC) of particle-antiparticle pairs are predicted to appear if hot and dense hadronic matter is formed in high energy nucleus-nucleus collisions. The BBC are related to in-medium mass-modification and squeezing of the quanta involved. Although the suppression of finite emission times were already known, the effects of finite system sizes and of collective phenomena had not been studied yet. Thus, for testing the survival and magnitude of the effect in more realistic situations, we study the BBC when mass-modification occurs in a finite sized, thermalized medium, considering a non-relativistically expanding fireball with finite emission time, and evaluating the width of the back-to-back correlation function. We show that the BBC signal indeed survives the expansion and flow effects, with sufficient magnitude to be observed at RHIC

Preconditioning for Mixed Finite Element Formulations of Elliptic Problems

KAUST Repository

Wildey, Tim; Xue, Guangri

2013-01-01

In this paper, we discuss a preconditioning technique for mixed finite element discretizations of elliptic equations. The technique is based on a block-diagonal approximation of the mass matrix which maintains the sparsity and positive definiteness of the corresponding Schur complement. This preconditioner arises from the multipoint flux mixed finite element method and is robust with respect to mesh size and is better conditioned for full permeability tensors than a preconditioner based on a diagonal approximation of the mass matrix. © Springer-Verlag Berlin Heidelberg 2013.

Low- and high-density nuclear equation of state and the hyperon puzzle

Energy Technology Data Exchange (ETDEWEB)

Colucci, Giuseppe; Sedrakian, Armen [Frankfurt Univ. (Germany). Inst. fuer Theoretische Physik

2013-07-01

The measurements of the unusually high mass of the millisecond pulsar PSR J1614-2230 (1.97 ± 0.04 M {sub CircleDot}) imposes a strong constraint on the nuclear Equation of State (EoS), in particular for what concerns the finite density behaviour of nuclear and neutron matter. In my talk I first discuss a model for the low-density part of the EoS, based on chiral one-pion exchange. I consider a self-consistent approach at finite temperature and density and show that even in a fully-relativistic theory the one-pion exchange contribution is dominated by a contact interaction. Then, a relativistic mean-field approach is used to discuss the high-density part of the EoS, including the presence of hyperons. In the latter, a density dependent parametrization is used and a parameter study on the hyperon-scalar meson coupling is performed.

Radiative nonrecoil nuclear finite size corrections of order $\\alpha(Z \\alpha)^5$ to the Lamb shift in light muonic atoms

OpenAIRE

Faustov, R. N.; Martynenko, A. P.; Martynenko, F. A.; Sorokin, V. V.

2017-01-01

On the basis of quasipotential method in quantum electrodynamics we calculate nuclear finite size radiative corrections of order α(Zα)5 to the Lamb shift in muonic hydrogen and helium. To construct the interaction potential of particles, which gives the necessary contributions to the energy spectrum, we use the method of projection operators to states with a definite spin. Separate analytic expressions for the contributions of the muon self-energy, the muon vertex operator and the amplitude...

Erratum to: Nuclear triaxiality in the A ∼ 160–170 mass region: the ...

Indian Academy of Sciences (India)

Erratum to: Nuclear triaxiality in the A ∼ 160–170 mass region: the story so far. S MUKHOPADHYAY1,∗ and W C MA2. 1Nuclear Physics Division, Bhabha Atomic Research Centre, Mumbai 400 085, India. 2Department of Physics, Mississippi State University, Mississippi State, Mississippi 39762, USA. ∗. Corresponding ...

Use of a finite range nucleon-nucleon interaction in the continuum shell model

International Nuclear Information System (INIS)

Faes, Jean-Baptiste

2007-01-01

The unification of nuclear structure and nuclear reactions was always a great challenge of nuclear physics. The extreme complexity of finite quantum systems lead in the past to a separate development of the nuclear structure and the nuclear reactions. A unified description of structure and reactions is possible within the continuum shell model. All previous applications of this model used the zero-range residual interaction and the finite depth local potential to generate the single-particle basis. In the thesis, we have presented an extension of the continuum shell model for finite-range nucleon-nucleon interaction and an arbitrary number of nucleons in the scattering continuum. The great advantage of the present formulation is the same two-body interaction used both to generate the single-particle basis and to describe couplings to the continuum states. This formulation opens a possibility for an ab initio continuum shell model studies with the same nucleon-nucleon interaction generating the nuclear mean field, the configuration mixing and the coupling to the scattering continuum. First realistic applications of the above model has been shown for spectra of "1"7F and "1"7O, and elastic phase-shifts in the reaction "1"6O(p, p)"1"6O. (author)

Research on digital system design of nuclear power valve

Science.gov (United States)

Zhang, Xiaolong; Li, Yuan; Wang, Tao; Dai, Ye

2018-04-01

With the progress of China's nuclear power industry, nuclear power plant valve products is in a period of rapid development, high performance, low cost, short cycle of design requirements for nuclear power valve is proposed, so there is an urgent need for advanced digital design method and integrated design platform to provide technical support. Especially in the background of the nuclear power plant leakage in Japan, it is more practical to improve the design capability and product performance of the nuclear power valve. The finite element numerical analysis is a common and effective method for the development of nuclear power valves. Nuclear power valve has high safety, complexity of valve chamber and nonlinearity of seal joint surface. Therefore, it is urgent to establish accurate prediction models for earthquake prediction and seal failure to meet engineering accuracy and calculation conditions. In this paper, a general method of finite element modeling for nuclear power valve assembly and key components is presented, aiming at revealing the characteristics and rules of finite element modeling of nuclear power valves, and putting forward aprecision control strategy for finite element models for nuclear power valve characteristics analysis.

Mass and Inertia Parameters for Nuclear Fission

International Nuclear Information System (INIS)

Damgaard, J.; Pauli, H.C.; Strutinsky, V.M.; Wong, C.Y.; Brack, M.; Stenholm-Jensen, A.

1969-01-01

The effective mass parameter and the moments of inertia for a deformed nucleus are evaluated using the cranking-model formalism. Special attention is paid to the dependence of these quantities on the intrinsic structure, which may arise due to shells in deformed nuclei. It is found that these inertial parameters are very much influenced by the shells present. The effective-mass parameter, which appears in an important way in the theory of spontaneous fission, fluctuates in the same manner as the shell-energy corrections. Its values at the fission barrier are up to two or three times larger than those at the equilibrium minima. This correlation comes about because for the effective mass the change in the local density of single-particle states is very important, much more so than the change in the pairing correlation. The moments of inertia which enter in the theory of angular anisotropy of fission fragments, also fluctuate as a function of the deformation. At low temperatures, the fluctuation is large and shows a distinct but more complicated correlation with the shells. At high temperatures, the moments of inertia fluctuate with a smaller amplitude about the rigid-body value in correlation with the energy-shell corrections. For the first-and second barriers, the rigid-body values are essentially reached at a nuclear temperature of 0.8 to 1.0 MeV. (author)

Standard test methods for chemical, mass spectrometric, spectrochemical, nuclear, and radiochemical analysis of nuclear-grade plutonium nitrate solutions

CERN Document Server

American Society for Testing and Materials. Philadelphia

2010-01-01

1.1 These test methods cover procedures for the chemical, mass spectrometric, spectrochemical, nuclear, and radiochemical analysis of nuclear-grade plutonium nitrate solutions to determine compliance with specifications. 1.2 The analytical procedures appear in the following order: Sections Plutonium by Controlled-Potential Coulometry Plutonium by Amperometric Titration with Iron(II) Plutonium by Diode Array Spectrophotometry Free Acid by Titration in an Oxalate Solution 8 to 15 Free Acid by Iodate Precipitation-Potentiometric Titration Test Method 16 to 22 Uranium by Arsenazo I Spectrophotometric Test Method 23 to 33 Thorium by Thorin Spectrophotometric Test Method 34 to 42 Iron by 1,10-Phenanthroline Spectrophotometric Test Method 43 to 50 Impurities by ICP-AES Chloride by Thiocyanate Spectrophotometric Test Method 51 to 58 Fluoride by Distillation-Spectrophotometric Test Method 59 to 66 Sulfate by Barium Sulfate Turbidimetric Test Method 67 to 74 Isotopic Composition by Mass Spectrom...

Centre de Spectrometrie Nucleaire et de Spectrometrie de Masse - CSNSM/Centre for nuclear and mass spectroscopy, Activity Report 2007-2009

International Nuclear Information System (INIS)

2010-01-01

The Centre for nuclear and mass spectroscopy (CSNSM) is a CNRS (National Centre for Scientific Research) laboratory affiliated with Paris-Sud University. The CSNSM is involved in pluri-disciplinary activities covering various scientific domains: Nuclear Structure (SNO), Nuclear Astrophysics (AN), Solid State Astrophysics (AS), Solid State Physics (PS) and Chemical Physics of Irradiation. This document presents the activity of the Centre during the 2007-2009 years: Nuclear Astrophysics; Solid State Astrophysics; Physics and Chemistry of Irradiation; Solid State Physics and cryogenic detectors; Solid State Physics, Condensed Matter and Irradiation; Structure of the Atomic Nucleus; Teaching and training activities; Spreading scientific culture; Administrative services; Electronics Group; Computer Department; Mechanics Department; RESET Service (Radiation-Environment-Safety- Maintenance-Work); SEMIRAMIS (ion source and ion beam handling)

Centre de Spectrometrie Nucleaire et de Spectrometrie de Masse - CSNSM/Centre for nuclear and mass spectroscopy, Activity Report 2010-2012

International Nuclear Information System (INIS)

2013-07-01

The Centre for nuclear and mass spectroscopy (CSNSM) is a CNRS (National Centre for Scientific Research) laboratory affiliated with Paris-Sud University. The CSNSM is involved in pluri-disciplinary activities covering various scientific domains: Nuclear Structure (SNO), Nuclear Astrophysics (AN), Solid State Astrophysics (AS), Solid State Physics (PS) and Chemical Physics of Irradiation. This document presents the activity of the Centre during the 2010-2012 years: Nuclear Astrophysics; Solid State Astrophysics; Physics and Chemistry of Irradiation; Solid State Physics Group; Condensed Matter and Irradiation: from fundamental to functional; Structure of the Atomic Nucleus; Teaching activities; Spreading scientific culture; Administrative services; Electronics Group; Computer Department; Mechanics Department; RESET Service (Radiation-Environment-Safety- Maintenance-Work); SEMIRAMIS (ion source and ion beam handling)

Consequences of the center-of-mass correction in nuclear mean-field models

International Nuclear Information System (INIS)

Bender, M.; Rutz, K.; Reinhard, P.G.; Maruhn, J.A.

2000-01-01

We study the influence of the scheme for the correction for spurious center-of-mass motion on the fit of effective interactions for self-consistent nuclear mean-field calculations. We find that interactions with very simple center-of-mass correction have significantly larger surface coefficients than interactions for which the center-of-mass correction was calculated for the actual many-body state during the fit. The reason for that is that the effective interaction has to counteract the wrong trends with nucleon number of all simplified schemes for center-of-mass correction which puts a wrong trend with mass number into the effective interaction itself. The effect becomes clearly visible when looking at the deformation energy of largely deformed systems, e.g. superdeformed states or fission barriers of heavy nuclei. (orig.)

Mass media differences in ''nuclear news'' reporting: implications for public opinions and acceptable safeguards

International Nuclear Information System (INIS)

Williams, A.; Williams, J.

1975-01-01

The technical and political issues of diversion safeguards are at best confusing to the general public, who derive most of their information about nuclear science from the mass media. This investigation compared ''nuclear news'' of all kinds in three national mass media for thirty-three months of 1972-1974 to examine the quantity and quality of atom-related news they provide. Findings from The New York Times, U. S. News and World Report, and the ABC, CBS, and NBC evening news indicate grounds for low public familiarity with essential concepts of safeguards, and consequently, for consumer value conflicts and weak popular supports for safeguards-related policy

Low-mass neutron stars: universal relations, the nuclear symmetry energy and gravitational radiation

Science.gov (United States)

O. Silva, Hector; Berti, Emanuele; Sotani, Hajime

2016-03-01

Compact objects such as neutron stars are ideal astrophysical laboratories to test our understanding of the fundamental interactions in the regime of supranuclear densities, unachievable by terrestrial experiments. Despite recent progress, the description of matter (i.e., the equation of state) at such densities is still debatable. This translates into uncertainties in the bulk properties of neutron stars, masses and radii for instance. Here we will consider low-mass neutron stars. Such stars are expected to carry important information on nuclear matter near the nuclear saturation point. It has recently been shown that the masses and surface redshifts of low-mass neutron stars smoothly depend on simple functions of the central density and of a characteristic parameter η associated with the choice of equation of state. Here we extend these results to slowly-rotating and tidally deformed stars and obtain empirical relations for various quantities, such as the moment of inertia, quadrupole moment and ellipticity, tidal and rotational Love numbers, and rotational apsidal constants. We discuss how these relations might be used to constrain the equation of state by future observations in the electromagnetic and gravitational-wave spectra.

Importance of banked tissues in the management of mass nuclear casualties

International Nuclear Information System (INIS)

Singh, Rita; Bhatnagar, P.K.

2009-01-01

Nuclear detonations are the most devastating of the weapons of mass destruction. There will be large number of casualties on detonation of nuclear weapon. Biological tissues like bone, skin, amniotic membrane and other soft tissues can be used for repair or reconstruction of the injured part of the body. Tissues from human donor can be processed and banked for orthopaedic, spinal, trauma and other surgical procedures. Radiation technology is used to sterilize the tissues to make them safe for clinical use. This paper highlights the importance of such banked tissues in the management of the casualties. (author)

Accelerator Mass Spectrometry at the Nuclear Science Laboratory: Applications to Nuclear Astrophysics

Science.gov (United States)

Collon, P.; Bauder, W.; Bowers, M.; Lu, W.; Ostdiek, K.; Robertson, D.

The Accelerator Mass Spectrometry (AMS) program at the Nuclear Science Laboratory of the University of Notre Dame is focused on measurements related to galactic radioactivity and to nucleosynthesis of main stellar burning as well as the production of so called Short-Lived Radionuclides (SLRs) in the Early Solar System (ESS). The research program is based around the 11MV FN tandem accelerator and the use of the gas-filled magnet technique for isobar separation. Using a technique that evolved from radiocarbon dating, this paper presents a number of research programs that rely on the use of an 11MV tandem accelerator at the center of the AMS program.

Perturbative QCD at finite temperature

International Nuclear Information System (INIS)

Altherr, T.

1989-03-01

We discuss an application of finite temperature QCD to lepton-pair production in a quark-gluon plasma. The perturbative calculation is performed within the realtime formalism. After cancellation of infrared and mass singularities, the corrections at O (α s ) are found to be very small in the region where the mass of the Drell-Yan pair is much larger than the temperature of the plasma. Interesting effects, however, appear at the annihilation threshold of the thermalized quarks

A study on the nonlinear finite element analysis of reinforced concrete structures: shell finite element formulation

Energy Technology Data Exchange (ETDEWEB)

Lee, Sang Jin; Seo, Jeong Moon

2000-08-01

The main goal of this research is to establish a methodology of finite element analysis of containment building predicting not only global behaviour but also local failure mode. In this report, we summerize some existing numerical analysis techniques to be improved for containment building. In other words, a complete description of the standard degenerated shell finite element formulation is provided for nonlinear stress analysis of nuclear containment structure. A shell finite element is derived using the degenerated solid concept which does not rely on a specific shell theory. Reissner-Mindlin assumptions are adopted to consider the transverse shear deformation effect. In order to minimize the sensitivity of the constitutive equation to structural types, microscopic material model is adopted. The four solution algorithms based on the standard Newton-Raphson method are discussed. Finally, two numerical examples are carried out to test the performance of the adopted shell medel.

A study on the nonlinear finite element analysis of reinforced concrete structures: shell finite element formulation

International Nuclear Information System (INIS)

Lee, Sang Jin; Seo, Jeong Moon

2000-08-01

The main goal of this research is to establish a methodology of finite element analysis of containment building predicting not only global behaviour but also local failure mode. In this report, we summerize some existing numerical analysis techniques to be improved for containment building. In other words, a complete description of the standard degenerated shell finite element formulation is provided for nonlinear stress analysis of nuclear containment structure. A shell finite element is derived using the degenerated solid concept which does not rely on a specific shell theory. Reissner-Mindlin assumptions are adopted to consider the transverse shear deformation effect. In order to minimize the sensitivity of the constitutive equation to structural types, microscopic material model is adopted. The four solution algorithms based on the standard Newton-Raphson method are discussed. Finally, two numerical examples are carried out to test the performance of the adopted shell medel

« Culture populaire », « culture de masse » : une définition ou un préalable ?

OpenAIRE

Ory, Pascal

2017-01-01

Parmi les notions en usage dans le champ historien, celles de « culture populaire » et de « culture de masse » se caractérisent par une définition des plus incertaines – incertitude encore aggravée par la tendance de certains à les confondre l’une avec l’autre. Je voudrais ici restreindre cette incertitude en proposant, en effet, une telle définition. Mais comme – je l’annonce d’emblée – je rapprocherai l’une de l’autre plus que je ne les distinguerai, j’espère ne pas ajouter à la confusion… ...

Nuclear Forensics: Measurements of Uranium Oxides Using Time-of-Flight Secondary Ion Mass Spectrometry (TOF-SIMS)

Science.gov (United States)

2010-03-01

Isotope Ratio Analysis of Actinides , Fission Products, and Geolocators by High- efficiency Multi-collector Thermal Ionization Mass Spectrometry...Information, 1999. Hou, Xiaolin, and Per Roos. “ Critical Comparison of radiometric and Mass Spectrometric Methods for the Determination of...NUCLEAR FORENSICS: MEASUREMENTS OF URANIUM OXIDES USING TIME-OF-FLIGHT SECONDARY ION MASS

Administrative Procedure Act and mass procedures (illustrated by the nuclear licensing procedure)

International Nuclear Information System (INIS)

Naumann, R.

1977-01-01

The report deals with the administrative procedure law of 25.5.76 of the Fed. Government, esp. with its meaning for the administrative procedures for the permission for nuclear power plants, as fas ar so-called mass procedures are concerned. (UN) [de

Description of nuclear properties

International Nuclear Information System (INIS)

Faessler, A.

1991-01-01

The lectures want to give a survey about new developments in the description of nuclei. In a first chapter we try to derive nuclear properties from the basis theory of quantum chromodynamics. This is not rigorously possible. There are still many cracks in the bridge between QCD and nuclear structure. The basic ingredient for nuclear structure calculations is the nucleon-nucleon interaction. We shall discuss the nucleon-nucleon interaction in a quark model. In a further chapter we discuss the way to come from a bare nucleon-nucleon interaction in free space to an effective nucleon-nucleon interaction in a limited model space for nuclear structure calculations. Such nuclear structure calculations can be done as shell model calculations. But they are due to the large number of configurations limited to light nuclei. We discuss possibilities (MONSTER and VAMPIR) to enlarge the model space for medium heavy and heavy nuclei. As the example of the low lying isovector 1 + states we discuss collective models (Bohr - Mottelson Model, interacting Boson Model) with proton and neutron degrees of freedom. The same states can also be described microscopically with the Quasi-Particle Random Phase Approximation (QRPA). We discuss the removal of spurious states in RPA. We also discuss the calculation of form factors and compare with inelastic electron scattering data. Finally we apply QRPA to the double-beta decay. Grand unified models predict, that the neutrino is identical with his antiparticle, that it has a finite mass and a weak right-handed interaction. If these properties are found the standard model of the strong and the electro-weak interaction can not be correct. Presently we can only derive from lower limits of the half lives of neutrinoless double-beta decays upper limits of the neutrino mass and of the right-handedness of the weak interaction and lower limits of the mass of the right handed heavy vector boson, if a specific grand unified model is given. (author)

Mechanical and chemical spinodal instabilities in finite quantum systems

International Nuclear Information System (INIS)

Colonna, M.; Chomaz, Ph.; Ayik, S.

2001-01-01

Self consistent quantum approaches are used to study the instabilities of finite nuclear systems. The frequencies of multipole density fluctuations are determined as a function of dilution and temperature, for several isotopes. The spinodal region of the phase diagrams is determined and it appears reduced by finite size effects. The role of surface and volume instabilities is discussed. Important chemical effects are associated with mechanical disruption and may lead to isospin fractionation. (authors)

Ultraviolet finiteness of N = 8 supergravity, spontaneously broken by dimensional reduction

International Nuclear Information System (INIS)

Sezgin, E.; Nieuwenhuizen, P. van

1982-06-01

The one-loop corrections to scalar-scalar scattering in N = 8 supergravity with 4 masses from dimensional reduction, are finite. We discuss various mechanisms that cancel the cosmological constant and infra-red divergences due to finite but non-vanishing tadpoles. (author)

Reduction of Couplings: Applications in Finite Theories and the MSSM

CERN Document Server

Mondragón, Myriam; Tracas, Nick; Zoupanos, George

2017-01-01

The method of reduction of couplings is applied to a Finite Unified Theory and in the MSSM.We search for renormalization group invariant relations among couplings of a renormalizable theory which holds to all orders in perturbation theory. The method leads to relations, at the unification scale, between gauge and Yukawa couplings (in the dimensionless sectors of the theory) and relations among the couplings of the trilinear terms and the Yukawa couplings, as well as a sum rule among the scalar masses and the gaugino mass (in the soft breaking sector). In the Finite Unified Theory model we predict, with remarkable agreement with the experiment, the masses of the top and bottom quarks while our predictions for the light Higgs mass and the rest supersymmetric spectrum masses are in comfortable agreement with the LHC bounds on Higgs and supersymmetric particles. In the case of the reduced MSSM the predictions are less successful but recent improvements in the code used to calculate the Higgs masses give promises ...

Finite volume effects on the electric polarizability of neutral hadrons in lattice QCD

Science.gov (United States)

Lujan, M.; Alexandru, A.; Freeman, W.; Lee, F. X.

2016-10-01

We study the finite volume effects on the electric polarizability for the neutron, neutral pion, and neutral kaon using eight dynamically generated two-flavor nHYP-clover ensembles at two different pion masses: 306(1) and 227(2) MeV. An infinite volume extrapolation is performed for each hadron at both pion masses. For the neutral kaon, finite volume effects are relatively mild. The dependence on the quark mass is also mild, and a reliable chiral extrapolation can be performed along with the infinite volume extrapolation. Our result is αK0 phys=0.356 (74 )(46 )×10-4 fm3 . In contrast, for neutron, the electric polarizability depends strongly on the volume. After removing the finite volume corrections, our neutron polarizability results are in good agreement with chiral perturbation theory. For the connected part of the neutral pion polarizability, the negative trend persists, and it is not due to finite volume effects but likely sea quark charging effects.

Finiteness of broken N=4 super Yang-Mills theory

International Nuclear Information System (INIS)

Namazie, M.A.; Salam, A.; Strathdee, J.

1982-11-01

Using a light cone gauge formulation for N=4 extended supersymmetry, it is shown that an explicit breaking of the supersymmetry by addition of mass terms does not disturb off-shell finiteness to any order provided the sum of fermion masses equals the sum of scalar masses and appropriate cubic interactions between scalars are included. (author)

Nuclear-mass dependence of azimuthal beam-helicity and beam-charge asymmetries in deeply virtual Compton scattering

International Nuclear Information System (INIS)

Airapetian, A.; Akopov, Z.

2009-11-01

The nuclear-mass dependence of azimuthal cross section asymmetries with respect to charge and longitudinal polarization of the lepton beam is studied for hard exclusive electroproduction of real photons. The observed beam-charge and beam-helicity asymmetries are attributed to the interference between the Bethe-Heitler and deeply virtual Compton scattering processes. For various nuclei, the asymmetries are extracted for both coherent and incoherent-enriched regions, which involve different (combinations of) generalized parton distributions. For both regions, the asymmetries are compared to those for a free proton, and no nuclear-mass dependence is found. (orig.)

EFFECT OF CENTRAL MASS CONCENTRATION ON THE FORMATION OF NUCLEAR SPIRALS IN BARRED GALAXIES

International Nuclear Information System (INIS)

Thakur, Parijat; Jiang, I.-G.; Ann, H. B.

2009-01-01

We have performed smoothed particle hydrodynamics simulations to study the response of the central kiloparsec region of a gaseous disk to the imposition of nonaxisymmetric bar potentials. The model galaxies are composed of three axisymmetric components (halo, disk, and bulge) and a nonaxisymmetric bar. These components are assumed to be invariant in time in the frame corotating with the bar. The potential of spherical γ-models of Dehnen is adopted for the bulge component whose density varies as r -γ near the center and r -4 at larger radii and, hence, possesses a central density core for γ = 0 and cusps for γ>0. Since the central mass concentration of the model galaxies increases with the cusp parameter γ, we have examined here the effect of the central mass concentration by varying the cusp parameter γ on the mechanism responsible for the formation of the symmetric two-armed nuclear spirals in barred galaxies. Our simulations show that the symmetric two-armed nuclear spirals are formed by hydrodynamic spiral shocks driven by the gravitational torque of the bar for the models with γ = 0 and 0.5. On the other hand, the symmetric two-armed nuclear spirals in the models with γ = 1 and 1.5 are explained by gas density waves. Thus, we conclude that the mechanism responsible for the formation of symmetric two-armed nuclear spirals in barred galaxies changes from hydrodynamic shocks to gas density waves as the central mass concentration increases from γ = 0 to 1.5.

Radiative nonrecoil nuclear finite size corrections of order α(Zα)5 to the hyperfine splitting of S-states in muonic hydrogen

International Nuclear Information System (INIS)

Faustov, R.N.; Martynenko, A.P.; Martynenko, G.A.; Sorokin, V.V.

2014-01-01

On the basis of quasipotential method in quantum electrodynamics we calculate nuclear finite size radiative corrections of order α(Zα) 5 to the hyperfine structure of S-wave energy levels in muonic hydrogen and muonic deuterium. For the construction of the particle interaction operator we employ the projection operators on the particle bound states with definite spins. The calculation is performed in the infrared safe Fried–Yennie gauge. Modern experimental data on the electromagnetic form factors of the proton and deuteron are used.

Radiative nonrecoil nuclear finite size corrections of order α(Zα)5 to the Lamb shift in light muonic atoms

Science.gov (United States)

Faustov, R. N.; Martynenko, A. P.; Martynenko, F. A.; Sorokin, V. V.

2017-12-01

On the basis of quasipotential method in quantum electrodynamics we calculate nuclear finite size radiative corrections of order α(Zα) 5 to the Lamb shift in muonic hydrogen and helium. To construct the interaction potential of particles, which gives the necessary contributions to the energy spectrum, we use the method of projection operators to states with a definite spin. Separate analytic expressions for the contributions of the muon self-energy, the muon vertex operator and the amplitude with spanning photon are obtained. We present also numerical results for these contributions using modern experimental data on the electromagnetic form factors of light nuclei.

Isospin breaking in nuclear physics: The Nolen-Schiffer effect

International Nuclear Information System (INIS)

Adami, C.; Brown, G.E.

1991-01-01

Using the QCD sum rules we calculate the neutron-proton mass difference at zero density as a function of the difference in bare quark mass m d -m u . We confirm results of Hatsuda, Hoegaasen and Prakash that the largest term results from the difference in up and down quark condensates, the explicit C (m d -m u ) entering with the opposite sign. The quark condensates are then extended to finite density to estimate the Nolen-Schiffer effect. The neutron-proton mass difference is extremely density dependent, going to zero at roughly nuclear matter density. The Ioffe formula for the nucleon mass is interpreted as a derivation, within the QCD sum rule approach, of the Nambu-Jona-Lasinio formula. This clarifies the N c counting and furthermore provides an alternative interpretation of the Borel mass. We compare calculations in the constituent quark model treated in the Nambu-Jona-Lasinio formalism with ours in the QCD sum rule approach. (orig.)

A comparison study on the performance of lower order solid finite element for elastic analysis of plate and shell structures

International Nuclear Information System (INIS)

Lee, Young Jung; Lee, Sang Jin; Choun, Young Sun; Seo, Jeong Moon

2003-05-01

The objective of this research is to assess the performance of lower order solid finite elements which will be ultimately applied into the safety analysis of nuclear containment building. For the safety analysis of large structures such as nuclear containment building, efficient lower order finite element is necessarily required to calculate the structural response of containment building with low computational cost. In this study, the state of the art formulations of lower order solid finite element are throughly reviewed and the best possible solid finite element is adopted into the development of nuclear containment analysis system. Three 8-node solid finite elements based on standard strain-displacement relationship, B-bar method and EAS method are implemented as computer modules and completely tested with various plate and shell structures. The present results can be directly applied into the analysis code development for general reinforced concrete structures

Investigation of an orbital mass - the role of nuclear medicine

International Nuclear Information System (INIS)

Dunlop, R. V.

2009-01-01

Full text:A 35 year old male presented, suffering from night sweats, occipital and frontal headaches, blurred vision, nausea and a decrease in appetite. He underwent a CT and MRI scan, which identified a 2.2cm lesion in the left orbit in an intra-conal position. This was suspected to be a cavernous haemangioma, although other tumours, such as Schwannoma could not be ruled out. A nuclear medicine labelled red blood cell study was performed which included initial dynamic images and early statics and 120min delayed images. SPECT/CT was also performed at the later time. The characteristic blood pool mismatch of low early and high delayed concentration of red blood cells confirmed suspicions of a cavernous haemangioma, which, although comprised mainly of blood vessels, has slow flow. Hence there is considerable delay before maximum activity is reached. The lesion was surgically removed. Histology reports confirmed the nuclear medicine results. Nuclear Medicine has the potential to play a significant role in the preoperative diagnosis of an orbital mass.

Application of mass-spring model in seismic analysis of liquid storage tank

International Nuclear Information System (INIS)

Liu Jiayi; Bai Xinran; Li Xiaoxuan

2013-01-01

There are many tanks for storing liquid in nuclear power plant. When seismic analysis is performed, swaying of liquid may change the mechanical parameters of those tanks, such as the center of mass and the moment of inertia, etc., so the load due to swaying of liquid can't be neglected. Mass-spring model is a simplified model to calculate the dynamic pressure of liquid in tank under earthquake, which is derived by the theory of Housner and given in the specification of seismic analysis of Safety-Related Nuclear Structures and Commentary-4-98 (ASCE-4-98 for short hereinafter). According to the theory of Housner and ASCE-4-98, the mass-spring 3-D FEM model for storage tank and liquid in it was established, by which the force of stored liquid acted on liquid storage tank in nuclear power plant under horizontal seismic load was calculated. The calculated frequency of liquid swaying and effect of liquid convection on storage tank were compared with those calculated by simplified formula. It is shown that the results of 3-D FEM model are reasonable and reliable. Further more, it is more direct and convenient compared with description in ASCE-4-98 when the mass-spring model is applied to 3-D FEM model for seismic analysis, from which the displacement and stress distributions of the plate-shell elements or the 3-D solid finite elements can be obtained directly from the seismic input model. (authors)

Nuclear quantum shape-phase transitions in odd-mass systems

Science.gov (United States)

Quan, S.; Li, Z. P.; Vretenar, D.; Meng, J.

2018-03-01

Microscopic signatures of nuclear ground-state shape-phase transitions in odd-mass Eu isotopes are explored starting from excitation spectra and collective wave functions obtained by diagonalization of a core-quasiparticle coupling Hamiltonian based on energy density functionals. As functions of the physical control parameter—the number of nucleons—theoretical low-energy spectra, two-neutron separation energies, charge isotope shifts, spectroscopic quadrupole moments, and E 2 reduced transition matrix elements accurately reproduce available data and exhibit more-pronounced discontinuities at neutron number N =90 compared with the adjacent even-even Sm and Gd isotopes. The enhancement of the first-order quantum phase transition in odd-mass systems can be attributed to a shape polarization effect of the unpaired proton which, at the critical neutron number, starts predominantly coupling to Gd core nuclei that are characterized by larger quadrupole deformation and weaker proton pairing correlations compared with the corresponding Sm isotopes.

Finite-temperature behavior of mass hierarchies in supersymmetric theories

International Nuclear Information System (INIS)

Ginsparg, P.

1982-01-01

It is shown that Witten's mechanism for producing a large gauge hierarchy in supersymmetric theories leads to a novel symmetry behavior at finite temperature. The exponentially large expectation value in such models develops at a critical temperature of order of the small (supersymmetry-breaking) scale. The phase transition can proceed without need of vacuum tunnelling. Models based on Witten's mechanism thus require a reexamination of the standard cosmological treatment of grand unified theories. (orig.)

Penning-trap mass spectrometry and mean-field study of nuclear shape coexistence in the neutron-deficient lead region

Science.gov (United States)

Manea, V.; Ascher, P.; Atanasov, D.; Barzakh, A. E.; Beck, D.; Blaum, K.; Borgmann, Ch.; Breitenfeldt, M.; Cakirli, R. B.; Cocolios, T. E.; Day Goodacre, T.; Fedorov, D. V.; Fedosseev, V. N.; George, S.; Herfurth, F.; Kowalska, M.; Kreim, S.; Litvinov, Yu. A.; Lunney, D.; Marsh, B.; Neidherr, D.; Rosenbusch, M.; Rossel, R. E.; Rothe, S.; Schweikhard, L.; Wienholtz, F.; Wolf, R. N.; Zuber, K.

2017-05-01

We present a study of nuclear shape coexistence in the region of neutron-deficient lead isotopes. The midshell gold isotopes 180,185,188,190Au (Z =79 ), the two long-lived nuclear states in 197At (Z =85 ), and the neutron-rich nuclide 219At were produced by the ISOLDE facility at CERN and their masses were determined with the high-precision Penning-trap mass spectrometer ISOLTRAP. The studied gold isotopes address the trend of binding energies in a region of the nuclear chart where the nuclear charge radii show pronounced discontinuities. Significant deviations from the atomic-mass evaluation were found for Au,190188. The new trend of two-neutron separation energies is smoother, although it does reveal the onset of deformation. The origin of this effect is interpreted in connection to the odd-even staggering of binding energies, as well as theoretically by Hartree-Fock-Bogoliubov calculations including quasiparticle blocking. The role of blocking for reproducing the large odd-even staggering of charge radii in the mercury isotopic chain is illustrated.

Low mass dilepton production at the SPS probing hot and dense nuclear matter

CERN Document Server

Pérez de los Heros, C; Baur, R; Breskin, Amos; Chechik, R; Drees, A; Jacob, C; Faschingbauer, U; Fisher, P H; Fraenkel, Zeev; Fuchs, C; Gatti, E; Glässel, P; Günzel, T F; Hess, F; Irmscher, D; Lenkeit, B C; Olsen, L H; Panebratsev, Yu A; Pfeiffer, A; Ravinovich, I; Rehak, P; Schön, A; Schükraft, Jürgen; Sampietro, M; Shimansky, S S; Shor, A; Specht, H J; Steiner, V; Tapprogge, Stefan; Tel-Zur, G; Tserruya, Itzhak; Ullrich, T S; Wurm, J P; Yurevich, V I

1996-01-01

CERES and HELIOS-3 have detected a significant enhancement of low--mass dileptons in nuclear collisions at 200 GeV/nucleon with respect to the expected ``conventional'' sources. The onset of the excess, starting at a mass of $\\sim2m_{\\pi}$, and the possibility of a quadratic dependence on the event multiplicity suggest the opening of the $\\pi^+\\pi^-\\rightarrow e^+e^-(\\mu^+\\mu^-)$ annihilation channel. This would be the first observation of thermal radiation from dense hadronic matter. Possible interpretations of these results are presented, including the reduction of the $\\rho$ mass due to partial restoration of chiral symmetry in the dense fireball formed in the collision.

Research in theoretical nuclear physics

International Nuclear Information System (INIS)

1989-08-01

This report discusses the following areas of investigation of the Stony Brook Nuclear Theory Group: the physics of hadrons; QCD and the nucleus; QCD at finite temperature and high density; nuclear astrophysics; nuclear structure and many-body theory; and heavy ion physics

Modification of the finite element heat and mass transfer code (FEHMN) to model multicomponent reactive transport

International Nuclear Information System (INIS)

Viswanathan, H.S.

1995-01-01

The finite element code FEHMN is a three-dimensional finite element heat and mass transport simulator that can handle complex stratigraphy and nonlinear processes such as vadose zone flow, heat flow and solute transport. Scientists at LANL have been developed hydrologic flow and transport models of the Yucca Mountain site using FEHMN. Previous FEHMN simulations have used an equivalent K d model to model solute transport. In this thesis, FEHMN is modified making it possible to simulate the transport of a species with a rigorous chemical model. Including the rigorous chemical equations into FEHMN simulations should provide for more representative transport models for highly reactive chemical species. A fully kinetic formulation is chosen for the FEHMN reactive transport model. Several methods are available to computationally implement a fully kinetic formulation. Different numerical algorithms are investigated in order to optimize computational efficiency and memory requirements of the reactive transport model. The best algorithm of those investigated is then incorporated into FEHMN. The algorithm chosen requires for the user to place strongly coupled species into groups which are then solved for simultaneously using FEHMN. The complete reactive transport model is verified over a wide variety of problems and is shown to be working properly. The simulations demonstrate that gas flow and carbonate chemistry can significantly affect 14 C transport at Yucca Mountain. The simulations also provide that the new capabilities of FEHMN can be used to refine and buttress already existing Yucca Mountain radionuclide transport studies

Neutron Flux Interpolation with Finite Element Method in the Nuclear Fuel Cell Calculation using Collision Probability Method

International Nuclear Information System (INIS)

Shafii, M. Ali; Su'ud, Zaki; Waris, Abdul; Kurniasih, Neny; Ariani, Menik; Yulianti, Yanti

2010-01-01

Nuclear reactor design and analysis of next-generation reactors require a comprehensive computing which is better to be executed in a high performance computing. Flat flux (FF) approach is a common approach in solving an integral transport equation with collision probability (CP) method. In fact, the neutron flux distribution is not flat, even though the neutron cross section is assumed to be equal in all regions and the neutron source is uniform throughout the nuclear fuel cell. In non-flat flux (NFF) approach, the distribution of neutrons in each region will be different depending on the desired interpolation model selection. In this study, the linear interpolation using Finite Element Method (FEM) has been carried out to be treated the neutron distribution. The CP method is compatible to solve the neutron transport equation for cylindrical geometry, because the angle integration can be done analytically. Distribution of neutrons in each region of can be explained by the NFF approach with FEM and the calculation results are in a good agreement with the result from the SRAC code. In this study, the effects of the mesh on the k eff and other parameters are investigated.

Isotopic Determination of Nuclear Materials Using Nuclear Fission Track Registration Technique and Thermal Ionization Mass Spectrometric Technique

International Nuclear Information System (INIS)

Jeon, Young Sin; Pyo, Hyeong Yeol; Park, Yong Joon; Song, Kyu Seok; Kim, Won Ho; Jee, Kwang Yong

2007-05-01

It is very important to develope the technology for the determination of isotopic ratios of hot particles( 234 U, 235 U, 236 U etc.) detected from swipe samples of various nuclear facilities. This technology is highly competitive internationally and has to be established independently as long as our government maintains atomic energy and treats nuclear materials. In this text, sample pretreatment procedure, gamma-ray counting, alpha or fission track techniques, isotopic analysis of U and Pu, background problems and detection limits for mass determination, and their application to the real swipe sample were described with detailed procedure. This technology would contribute to the Korean economy's high growth rate as well as to superiority of government's leading research and development programs if successfully established

Nuclear assay of coal. Volume 6. Mass flow devices for coal handling. Final report

International Nuclear Information System (INIS)

Gozani, T.; Elias, E.; Bevan, R.

1980-04-01

The mass of coal entering the boiler per unit time is an essential parameter for determining the total rate of heat input. The mass flow rate of coal on a conveyor belt is generally determined as a product of the instantaneous mass of material on a short section of the belt and the belt velocity. Belt loading could be measured by conventional transducers incorporating mechanical or electromechanical weighers or by gamma-ray attenuation gauge. This report reviews the state of the art in mass flow devices for coal handling. The various methods are compared and commented upon. Special design issues are discussed relative to incorporating a mass flow measuring device in a Continuous On-Line Nuclear Analysis of Coal (CONAC) system

Nuclear research with heavy ions

International Nuclear Information System (INIS)

Kaplan, M.

1992-08-01

This report discusses the following topics; studies of light-charged-particle emission from fission and er reactions in the system 344-MeV 28 Si+ 121 Sb → 149 Tb; the role of reversed kinematics and double kinematic solutions in nuclear reactions studies; improvements in interactive data analysis and graphical representations; studies of the reaction 856-MeV 98 Mo + 51 V→ 149 Tb(E*=224-MeV): emission of intermediate-mass fragments; particle-particle correlations in compound nucleus reactions: preliminary consideration of lifetime estimates from small angle data; light particle emission studies using a new scintillator array; statistical evaporation calculations: developments with the computer codes LILITA-N90 and CASCADE; star collaboration studies: simulations for the conceptual design of the STAR detector system at RHIC; asymmetric fission of 149Tb* from the finite-range, rotating-liquid-drop model: mean total kinetic energies for binary fragmentation; and charged-particle evaporation from hot composite nuclei: evidence over a broad z range for distortions from cold nuclear profiles

Lattice QCD for nuclear physics

CERN Document Server

Meyer, Harvey

2015-01-01

With ever increasing computational resources and improvements in algorithms, new opportunities are emerging for lattice gauge theory to address key questions in strongly interacting systems, such as nuclear matter. Calculations today use dynamical gauge-field ensembles with degenerate light up/down quarks and the strange quark and it is possible now to consider including charm-quark degrees of freedom in the QCD vacuum. Pion masses and other sources of systematic error, such as finite-volume and discretization effects, are beginning to be quantified systematically. Altogether, an era of precision calculation has begun, and many new observables will be calculated at the new computational facilities.  The aim of this set of lectures is to provide graduate students with a grounding in the application of lattice gauge theory methods to strongly interacting systems, and in particular to nuclear physics.  A wide variety of topics are covered, including continuum field theory, lattice discretizations, hadron spect...

Leptodermous expansion of finite-nucleus incompressibility

International Nuclear Information System (INIS)

Nayak, R.C.

1990-01-01

We consider the influence of higher-order terms in the leptodermous expansion used to extract the incompressibility K v of infinite nuclear matter from data on the breathing mode of finite nuclei. The terms we calculate are the curvature term K cv A -2/3 , the surface-symmetry term K ss I 2 A -1/3 , the quartic volume-symmetry term K 4 I 4 , and a Coulomb-exchange term. Working within the framework of the scaling model we derive expressions for their coefficients in terms of quantities that are defined for infinite and semi-infinite nuclear matter. We calculate these coefficients for four different Skyrme-type forces, using the extended Thomas-Fermi (ETF) approximation. With the same forces we also calculate the incompressibility K (A, I) for a number of finite nuclei, fit the results to the leptodermous expansion, and thereby extract new results for the same coefficients. The comparison of the two calculations shows that the leptodermous expansion is converging rapidly. Of the new terms, the term K 4 I 4 is quite negligible, the curvature term should be included, and we discuss to what extent the other higher-order terms are significant. (orig.)

Nuclear Resonance Fluorescence to Measure Plutonium Mass in Spent Nuclear Fuel

Energy Technology Data Exchange (ETDEWEB)

Ludewigt, Bernhard A; Quiter, Brian J.; Ambers, Scott D.

2011-01-14

The Next Generation Safeguard Initiative (NGSI) of the U.S Department of Energy is supporting a multi-lab/university collaboration to quantify the plutonium (Pu) mass in spent nuclear fuel (SNF) assemblies and to detect the diversion of pins with non-destructive assay (NDA) methods. The following 14 NDA techniques are being studied: Delayed Neutrons, Differential Die-Away, Differential Die-Away Self-Interrogation, Lead Slowing Down Spectrometer, Neutron Multiplicity, Passive Neutron Albedo Reactivity, Total Neutron (Gross Neutron), X-Ray Fluorescence, {sup 252}Cf Interrogation with Prompt Neutron Detection, Delayed Gamma, Nuclear Resonance Fluorescence, Passive Prompt Gamma, Self-integration Neutron Resonance Densitometry, and Neutron Resonance Transmission Analysis. Understanding and maturity of the techniques vary greatly, ranging from decades old, well-understood methods to new approaches. Nuclear Resonance Fluorescence (NRF) is a technique that had not previously been studied for SNF assay or similar applications. Since NRF generates isotope-specific signals, the promise and appeal of the technique lies in its potential to directly measure the amount of a specific isotope in an SNF assay target. The objectives of this study were to design and model suitable NRF measurement methods, to quantify capabilities and corresponding instrumentation requirements, and to evaluate prospects and the potential of NRF for SNF assay. The main challenge of the technique is to achieve the sensitivity and precision, i.e., to accumulate sufficient counting statistics, required for quantifying the mass of Pu isotopes in SNF assemblies. Systematic errors, considered a lesser problem for a direct measurement and only briefly discussed in this report, need to be evaluated for specific instrument designs in the future. Also, since the technical capability of using NRF to measure Pu in SNF has not been established, this report does not directly address issues such as cost, size

Explicit dynamics for numerical simulation of crack propagation by the extended finite element method

International Nuclear Information System (INIS)

Menouillard, T.

2007-09-01

Computerized simulation is nowadays an integrating part of design and validation processes of mechanical structures. Simulation tools are more and more performing allowing a very acute description of the phenomena. Moreover, these tools are not limited to linear mechanics but are developed to describe more difficult behaviours as for instance structures damage which interests the safety domain. A dynamic or static load can thus lead to a damage, a crack and then a rupture of the structure. The fast dynamics allows to simulate 'fast' phenomena such as explosions, shocks and impacts on structure. The application domain is various. It concerns for instance the study of the lifetime and the accidents scenario of the nuclear reactor vessel. It is then very interesting, for fast dynamics codes, to be able to anticipate in a robust and stable way such phenomena: the assessment of damage in the structure and the simulation of crack propagation form an essential stake. The extended finite element method has the advantage to break away from mesh generation and from fields projection during the crack propagation. Effectively, crack is described kinematically by an appropriate strategy of enrichment of supplementary freedom degrees. Difficulties connecting the spatial discretization of this method with the temporal discretization of an explicit calculation scheme has then been revealed; these difficulties are the diagonal writing of the mass matrix and the associated stability time step. Here are presented two methods of mass matrix diagonalization based on the kinetic energy conservation, and studies of critical time steps for various enriched finite elements. The interest revealed here is that the time step is not more penalizing than those of the standard finite elements problem. Comparisons with numerical simulations on another code allow to validate the theoretical works. A crack propagation test in mixed mode has been exploited in order to verify the simulation

Numerical solution of multi group-Two dimensional- Adjoint equation with finite element method

International Nuclear Information System (INIS)

Poursalehi, N.; Khalafi, H.; Shahriari, M.; Minoochehr

2008-01-01

Adjoint equation is used for perturbation theory in nuclear reactor design. For numerical solution of adjoint equation, usually two methods are applied. These are Finite Element and Finite Difference procedures. Usually Finite Element Procedure is chosen for solving of adjoint equation, because it is more use able in variety of geometries. In this article, Galerkin Finite Element method is discussed. This method is applied for numerical solving multi group, multi region and two dimensional (X, Y) adjoint equation. Typical reactor geometry is partitioned with triangular meshes and boundary condition for adjoint flux is considered zero. Finally, for a case of defined parameters, Finite Element Code was applied and results were compared with Citation Code

A finite element modeling method for predicting long term corrosion rates

International Nuclear Information System (INIS)

Fu, J.W.; Chan, S.

1984-01-01

For the analyses of galvanic corrosion, pitting and crevice corrosion, which have been identified as possible corrosion processes for nuclear waste isolation, a finite element method has been developed for the prediction of corrosion rates. The method uses a finite element mesh to model the corrosive environment and the polarization curves of metals are assigned as the boundary conditions to calculate the corrosion cell current distribution. A subroutine is used to calculate the chemical change with time in the crevice or the pit environments. In this paper, the finite element method is described along with experimental confirmation

Storage ion trap of an 'In-Flight Capture' type for precise mass measurement of radioactive nuclear reaction products and fission fragments

International Nuclear Information System (INIS)

Tarantin, N.I.

2001-01-01

Data on nuclear masses provide a basis for creating and testing various nuclear models. A tandem system of FLNR comprised of the U-400M cyclotron, the COMBAS magnetic separator and the mass-spectrometric ion trap of an 'in-flight capture' type is considered as a possible complex for producing of the short-lived nuclei in fragmentation reactions by heavy ions and for precise mass measurement of these nuclei. The plan of scientific and technical FLNR research includes a project DRIBs for producing beams of accelerated radioactive nuclear reaction products and photofission fragments. This project proposes also precise mass measurements of the fission fragment with the help of the ion trap. The in-flight entrance of the ions and their capture in the mass-spectrometric ion trap using the monochromatizing degrader, the static electric and magnetic fields and a new invention, a magnetic unidirectional transporting ventil, is considered

Coupling of mass and charge distributions for low excited nuclear fission

International Nuclear Information System (INIS)

Salamatin, V.S.; )

2000-01-01

The simple model for calculation of charge distributions of fission fragments for low exited nuclear fission from experimental mass distributions is offered. The model contains two parameters, determining amplitude of even-odd effect of charge distributions and its dependence on excitation energy. Results for reactions 233 U(n th ,f), 235 U(n th ,f), 229 Th(n th ,f), 249 Cf(n th ,f) are spent [ru

Finite element analysis of ion transport in solid state nuclear waste form materials

Science.gov (United States)

Rabbi, F.; Brinkman, K.; Amoroso, J.; Reifsnider, K.

2017-09-01

Release of nuclear species from spent fuel ceramic waste form storage depends on the individual constituent properties as well as their internal morphology, heterogeneity and boundary conditions. Predicting the release rate is essential for designing a ceramic waste form, which is capable of effectively storing the spent fuel without contaminating the surrounding environment for a longer period of time. To predict the release rate, in the present work a conformal finite element model is developed based on the Nernst Planck Equation. The equation describes charged species transport through different media by convection, diffusion, or migration. And the transport can be driven by chemical/electrical potentials or velocity fields. The model calculates species flux in the waste form with different diffusion coefficient for each species in each constituent phase. In the work reported, a 2D approach is taken to investigate the contributions of different basic parameters in a waste form design, i.e., volume fraction, phase dispersion, phase surface area variation, phase diffusion co-efficient, boundary concentration etc. The analytical approach with preliminary results is discussed. The method is postulated to be a foundation for conformal analysis based design of heterogeneous waste form materials.

Volumes, Masses, and Surface Areas for Shippingport LWBR Spent Nuclear Fuel in a DOE SNF Canister

International Nuclear Information System (INIS)

J.W. Davis

1999-01-01

The purpose of this calculation is to estimate volumes, masses, and surface areas associated with (a) an empty Department of Energy (DOE) 18-inch diameter, 15-ft long spent nuclear fuel (SNF) canister, (b) an empty DOE 24-inch diameter, 15-ft long SNF canister, (c) Shippingport Light Water Breeder Reactor (LWBR) SNF, and (d) the internal basket structure for the 18-in. canister that has been designed specifically to accommodate Seed fuel from the Shippingport LWBR. Estimates of volumes, masses, and surface areas are needed as input to structural, thermal, geochemical, nuclear criticality, and radiation shielding calculations to ensure the viability of the proposed disposal configuration

The dynamics of the nuclear disassembly in a field-theoretical model at finite entropies

International Nuclear Information System (INIS)

Knoll, J.; Strack, B.

1984-10-01

The expansion phase of a hot nuclear system as created in an energetic heavy-ion collision is calculated and discussed by a selfconsistent field-theoretical model. Dynamical instabilities arising during the expansion from strong fluctuations of the one-body density are included explicitely. First multiplicity distributions and mass spectra resulting from a series of numerical runs in a 2+1 dimensional model world are presented. The dependence of break-up dynamics both on the properties of the binding force and possible correlations in the initially compressed hot state are discussed. (orig.)

Decisive role of nuclear quantum effects on surface mediated water dissociation at finite temperature

Science.gov (United States)

Litman, Yair; Donadio, Davide; Ceriotti, Michele; Rossi, Mariana

2018-03-01

Water molecules adsorbed on inorganic substrates play an important role in several technological applications. In the presence of light atoms in adsorbates, nuclear quantum effects (NQEs) influence the structural stability and the dynamical properties of these systems. In this work, we explore the impact of NQEs on the dissociation of water wires on stepped Pt(221) surfaces. By performing ab initio molecular dynamics simulations with van der Waals corrected density functional theory, we note that several competing minima for both intact and dissociated structures are accessible at finite temperatures, making it important to assess whether harmonic estimates of the quantum free energy are sufficient to determine the relative stability of the different states. We thus perform ab initio path integral molecular dynamics (PIMD) in order to calculate these contributions taking into account the conformational entropy and anharmonicities at finite temperatures. We propose that when adsorption is weak and NQEs on the substrate are negligible, PIMD simulations can be performed through a simple partition of the system, resulting in considerable computational savings. We then calculate the full contribution of NQEs to the free energies, including also anharmonic terms. We find that they result in an increase of up to 20% of the quantum contribution to the dissociation free energy compared with the harmonic estimates. We also find that the dissociation process has a negligible contribution from tunneling but is dominated by zero point energies, which can enhance the rate of dissociation by three orders of magnitude. Finally we highlight how both temperature and NQEs indirectly impact dipoles and the redistribution of electron density, causing work function changes of up to 0.4 eV with respect to static estimates. This quantitative determination of the change in the work function provides a possible approach to determine experimentally the most stable configurations of water

High-accuracy mass determination of unstable nuclei with a Penning trap mass spectrometer

CERN Multimedia

2002-01-01

The mass of a nucleus is its most fundamental property. A systematic study of nuclear masses as a function of neutron and proton number allows the observation of collective and single-particle effects in nuclear structure. Accurate mass data are the most basic test of nuclear models and are essential for their improvement. This is especially important for the astrophysical study of nuclear synthesis. In order to achieve the required high accuracy, the mass of ions captured in a Penning trap is determined via their cyclotron frequency $ \

Radiative nonrecoil nuclear finite size corrections of order α(Zα){sup 5} to the hyperfine splitting of S-states in muonic hydrogen

Energy Technology Data Exchange (ETDEWEB)

Faustov, R.N. [Dorodnicyn Computing Centre, Russian Academy of Science, Vavilov Str. 40, 119991 Moscow (Russian Federation); Martynenko, A.P. [Samara State University, Pavlov Str. 1, 443011 Samara (Russian Federation); Samara State Aerospace University named after S.P. Korolyov, Moskovskoye Shosse 34, 443086 Samara (Russian Federation); Martynenko, G.A.; Sorokin, V.V. [Samara State University, Pavlov Str. 1, 443011 Samara (Russian Federation)

2014-06-02

On the basis of quasipotential method in quantum electrodynamics we calculate nuclear finite size radiative corrections of order α(Zα){sup 5} to the hyperfine structure of S-wave energy levels in muonic hydrogen and muonic deuterium. For the construction of the particle interaction operator we employ the projection operators on the particle bound states with definite spins. The calculation is performed in the infrared safe Fried–Yennie gauge. Modern experimental data on the electromagnetic form factors of the proton and deuteron are used.

Correlation Results for a Mass Loaded Vehicle Panel Test Article Finite Element Models and Modal Survey Tests

Science.gov (United States)

Maasha, Rumaasha; Towner, Robert L.

2012-01-01

High-fidelity Finite Element Models (FEMs) were developed to support a recent test program at Marshall Space Flight Center (MSFC). The FEMs correspond to test articles used for a series of acoustic tests. Modal survey tests were used to validate the FEMs for five acoustic tests (a bare panel and four different mass-loaded panel configurations). An additional modal survey test was performed on the empty test fixture (orthogrid panel mounting fixture, between the reverb and anechoic chambers). Modal survey tests were used to test-validate the dynamic characteristics of FEMs used for acoustic test excitation. Modal survey testing and subsequent model correlation has validated the natural frequencies and mode shapes of the FEMs. The modal survey test results provide a basis for the analysis models used for acoustic loading response test and analysis comparisons

6th international symposium on finite volumes for complex applications

CERN Document Server

Halama, Jan; Herbin, Raphaèle; Hubert, Florence; Fort, Jaroslav; FVCA 6; Finite Volumes for Complex Applications VI : Problems and perspectives

2011-01-01

Finite volume methods are used for various applications in fluid dynamics, magnetohydrodynamics, structural analysis or nuclear physics. A closer look reveals many interesting phenomena and mathematical or numerical difficulties, such as true error analysis and adaptivity, modelling of multi-phase phenomena or fitting problems, stiff terms in convection/diffusion equations and sources. To overcome existing problems and to find solution methods for future applications requires many efforts and always new developments. The goal of The International Symposium on Finite Volumes for Complex Applica

Charge symmetry breaking nuclear forces and the properties of nuclear matter

International Nuclear Information System (INIS)

Haensel, P.

1977-01-01

The charge symmetry breaking (CSB) component of the nuclear forces yields the charge asymmetric term Esub(a)(N-Z)/A in the nuclear binding energy of nuclear matter. Calculation performed with several models of the CSB nuclear forces, and accounting for the strong short-range two-body correlations, gives Esub(a) approximately -0.2 MeV at the normal nuclear density. The charge asymmetry of the effective nucleon-nucleon interaction is determined primarily by the CSB nuclear forces at the neutron excess, observed in finite nuclei. The exclusion principle and dispersion (self-consistency) effects of the nuclear medium decrease this charge asymmetry. (author)

Finite volume at two-loops in chiral perturbation theory

International Nuclear Information System (INIS)

Bijnens, Johan; Rössler, Thomas

2015-01-01

We calculate the finite volume corrections to meson masses and decay constants in two and three flavour Chiral Perturbation Theory to two-loop order. The analytical results are compared with the existing result for the pion mass in two-flavour ChPT and the partial results for the other quantities. We present numerical results for all quantities.

Chemical, mass spectrometric, spectrochemical, nuclear, and radiochemical analysis of nuclear-grade uranyl nitrate solutions

International Nuclear Information System (INIS)

Anon.

1981-01-01

The standard covers analytical procedures to determine compliance of nuclear-grade uranyl nitrate solution to specifications. The following methods are described in detail: uranium by ferrous sulfate reduction-potassium dichromate titrimetry and by ignition gravimetry; specific gravity by pycnometry; free acid by oxalate complexation; thorium by the Arsenazo(III) (photometric) method; chromium by the diphenylcarbazide (photometric) method; molybdenum by the thiocyanate (photometric) method; halogens separation by steam distillation; fluorine by specific ion electrode; halogen distillate analysis: chloride, bromide and iodide by amperometric microtitrimetry; bromine by the fluorescein (photometric) method; sulfate sulfur by (photometric) turbidimetry; phosphorus by the molybdenum blue (photometric) method; silicon by the molybdenum blue (photometric) method; carbon by persulfate oxidation-acid titrimetry; nonvolatile impurities by spectrography; volatile impurities by rotating-disk spark spectrography; boron by emission spectrography; impurity elements by spark source mass spectrography; isotopic composition by multiple filament surface-ionization mass spectrometry; uranium-232 by alpha spectrometry; total alpha activity by direct alpha counting; fission product activity by beta and gamma counting; entrained organic matter by infrared spectrophotometry

The Newtonian force experienced by a point mass near a finite cylindrical source

International Nuclear Information System (INIS)

Selvaggi, Jerry P; Salon, Sheppard; Chari, M V K

2008-01-01

The Newtonian gravitational force experienced by a point mass located at some external point from a thick-walled, hollow and uniform finite circular cylindrical body was recently solved by Lockerbie, Veryaskin and Xu (1993 Class. Quantum Grav. 10 2419). Their method of attack relied on the introduction of the circular cylindrical free-space Green function representation for the inverse distance which appears in the formulation of the Newtonian potential function. This ultimately leads Lockerbie et al to a final expression for the Newtonian potential function which is expressed as a double summation of even-ordered Legendre polynomials. However, the kernel of the cylindrical free-space Green function which is represented by an infinite integral of the product of two Bessel functions and a decaying exponential can be analytically evaluated in terms of a toroidal function. This leads to a simplification in the mathematical analysis developed by Lockerbie et al. Also, each term in the infinite series solution for the Newtonian potential function can be expressed in closed form in terms of elementary functions. The authors develop the Newtonian potential function by employing toroidal functions of zeroth order or Legendre functions of half-integral degree, Q m-1/2 (β)(Bouwkamp and de Bruijn 1947 J. Appl. Phys.18 562, Cohl et al 2001 Phys. Rev.A 64 052509-1, Selvaggi et al 2004 IEEE Trans. Magn.40 3278). These functions are monotonically decreasing and converge rapidly (Moon and Spencer 1961 Field Theory for Engineers (New Jersey: Van Nostrand Company) pp 368-76, Cohl and Tohline 1999 Astrophys. J.527 86). The introduction of the toroidal harmonic expansion leads to an infinite series solution for which each term can be expressed as an elementary function. This enables one to easily compute the axial and radial forces experienced by an internal or an external point mass

Radiocarbon mass balance for a Magnox nuclear power station

International Nuclear Information System (INIS)

Metcalfe, M.P.; Mills, R.W.

2015-01-01

Highlights: • First comprehensive assessment of C-14 arisings in a Magnox nuclear power station. • C-14 production in graphite and coolant gas quantified by activation modelling. • Principal C-14 production pathway is via C-13 with a small contribution from N-14. • C-14 mass balance model provides a basis for analyses on other reactors. - Abstract: Nuclear power generation in the United Kingdom is based principally on graphite-moderated gas-cooled reactors. The mass of irradiated graphite associated with these reactors, including material from associated experimental, prototype and plutonium production reactors, exceeds 96,000 tonnes. One of the principal long-lived radionuclides produced during graphite irradiation is radiocarbon (C-14). Its potential as a hazard must be taken into account in decommissioning and graphite waste management strategies. While C-14 production processes are well-understood, radionuclide distributions and concentrations need to be characterised. A common misconception is that generic statements can be made about C-14 precursors and their location. In fact, the composition of the original manufactured material, the chemical environment of the graphite during service and its irradiation history will all influence C-14 levels. The analysis presented here provides the first assessment of the principal C-14 activation pathways for a UK Magnox reactor. Activation modelling has been used to predict C-14 production rates in both the graphite core and the carbon dioxide coolant over a selected period of operation and the results compared with monitored site C-14 discharges. Principal activation routes have been identified, which should inform future graphite waste management strategies relating to radiocarbon

Finite element simulations of low-mass readout cables for the CBM Silicon Tracking System using RAPHAEL

Energy Technology Data Exchange (ETDEWEB)

Singla, M., E-mail: M.Singla@gsi.de [Goethe University, Frankfurt (Germany); GSI Helmholtzzentrum für Schwerionenforschung GmbH, Darmstadt (Germany); Chatterji, S.; Müller, W.F.J.; Kleipa, V.; Heuser, J.M. [GSI Helmholtzzentrum für Schwerionenforschung GmbH, Darmstadt (Germany)

2014-01-21

The first three-dimensional simulation study of thin multi-line readout cables using finite element simulation tool RAPHAEL is being reported. The application is the Silicon Tracking System (STS) of the fixed-target heavy-ion experiment Compressed Baryonic Matter (CBM), under design at the forthcoming accelerator center FAIR in Germany. RAPHAEL has been used to design low-mass analog readout cables with minimum possible Equivalent Noise Charge (ENC). Various trace geometries and trace materials have been explored in detail for this optimization study. These cables will bridge the distance between the microstrip detectors and the signal processing electronics placed at the periphery of the silicon tracking stations. SPICE modeling has been implemented in Sentaurus Device to study the transmission loss (dB loss) in cables and simulation has been validated with measurements. An optimized design having minimum possible ENC, material budget and transmission loss for the readout cables has been proposed.

Thermo-hydro-mechanical behavior of fractured rock mass

International Nuclear Information System (INIS)

Coste, F.

1997-12-01

The purpose of this research is to model Thermo-Hydro-Mechanical behavior of fractured rock mass regarding a nuclear waste re-depository. For this, a methodology of modeling was proposed and was applied to a real underground site (EDF site at Nouvelle Romanche). This methodology consists, in a first step, to determine hydraulic and mechanical REV. Beyond the greatest of these REV, development of a finite element code allows to model all the fractures in an explicit manner. The homogenized mechanical properties are determined in drained and undrained boundary conditions by simulating triaxial tests that represent rock mass subject to loading. These simulations allow to study the evolution of hydraulic and mechanical properties as a function of stress state. Drained and undrained boundary conditions enable to discuss the validity of assimilation of a fractured rock mass to a porous medium. The simulations lead to a better understanding of the behavior of the fractured rock masses and allow to show the dominant role of the shear behavior of the fractures on the hydraulic and mechanical homogenized properties. From a thermal point of view, as long as conduction is dominant, thermal properties of the rock mass are almost the same as those the intact rock. (author)

D mesons in asymmetric nuclear matter

International Nuclear Information System (INIS)

Mishra, Amruta; Mazumdar, Arindam

2009-01-01

We calculate the in-medium D and D meson masses in isospin-asymmetric nuclear matter in an effective chiral model. The D and D mass modifications arising from their interactions with the nucleons and the scalar mesons in the effective hadronic model are seen to be appreciable at high densities and have a strong isospin dependence. These mass modifications can open the channels of the decay of the charmonium states (Ψ ' ,χ c ,J/Ψ) to DD pairs in dense hadronic matter. The isospin asymmetry in the doublet D=(D 0 ,D + ) is seen to be particularly appreciable at high densities and should show in observables such as their production and flow in asymmetric heavy-ion collisions in the compressed baryonic matter experiments in the future facility of FAIR, GSI. The results of the present work are compared to calculations of the D(D) in-medium masses in the literature using the QCD sum rule approach, quark meson coupling model, and coupled channel approach as well as to those from studies of quarkonium dissociation using heavy-quark potentials from lattice QCD at finite temperatures

Double Beta Decay and Neutrino Masses Accuracy of the Nuclear Matrix Elements

International Nuclear Information System (INIS)

Faessler, Amand

2005-01-01

The neutrinoless double beta decay is forbidden in the standard model of the electroweak and strong interaction but allowed in most Grand Unified Theories (GUT's). Only if the neutrino is a Majorana particle (identical with its antiparticle) and if it has a mass, the neutrinoless double beta decay is allowed. Apart of one claim that the neutrinoless double beta decay in 76 Ge is measured, one has only upper limits for this transition probability. But even the upper limits allow to give upper limits for the electron Majorana neutrino mass and upper limits for parameters of GUT's and the minimal R-parity violating supersymmetric model. One further can give lower limits for the vector boson mediating mainly the right-handed weak interaction and the heavy mainly right-handed Majorana neutrino in left-right symmetric GUT's. For that one has to assume that the specific mechanism is the leading one for the neutrinoless double beta decay and one has to be able to calculate reliably the corresponding nuclear matrix elements. In the present contribution, one discusses the accuracy of the present status of calculating the nuclear matrix elements and the corresponding limits of GUT's and supersymmetric parameters

FINEDAN - an explicit finite-element calculation code for two-dimensional analyses of fast dynamic transients in nuclear reactor technology

International Nuclear Information System (INIS)

Adamik, V.; Matejovic, P.

1989-01-01

The problems are discussed of nonstationary, nonlinear dynamics of the continuum. A survey is presented of calculation methods in the given area with emphasis on the area of impact problems. A description is presented of the explicit finite elements method and its application to two-dimensional Cartesian and cylindrical configurations. Using the method the explicit calculation code FINEDAN was written which was tested in a series of verification calculations for different configurations and different types of continuum. The main characteristics are presented of the code and of some, of its practical applications. Envisaged trends of the development of the code and its possible applications in the technology of nuclear reactors are given. (author). 9 figs., 4 tabs., 10 refs

Calculation of media temperatures for nuclear sources in geologic depositories by a finite-length line source superposition model (FLLSSM)

Energy Technology Data Exchange (ETDEWEB)

Kays, W M; Hossaini-Hashemi, F [Stanford Univ., Palo Alto, CA (USA). Dept. of Mechanical Engineering; Busch, J S [Kaiser Engineers, Oakland, CA (USA)

1982-02-01

A linearized transient thermal conduction model was developed to economically determine media temperatures in geologic repositories for nuclear wastes. Individual canisters containing either high-level waste or spent fuel assemblies are represented as finite-length line sources in a continuous medium. The combined effects of multiple canisters in a representative storage pattern can be established in the medium at selected point of interest by superposition of the temperature rises calculated for each canister. A mathematical solution of the calculation for each separate source is given in this article, permitting a slow hand calculation. The full report, ONWI-94, contains the details of the computer code FLLSSM and its use, yielding the total solution in one computer output.

Application of finite-element method to three-dimensional nuclear reactor analysis

International Nuclear Information System (INIS)

Cheung, K.Y.

1985-01-01

The application of the finite element method to solve a realistic one-or-two energy group, multiregion, three-dimensional static neutron diffusion problem is studied. Linear, quadratic, and cubic serendipity box-shape elements are used. The resulting sets of simultaneous algebraic equations with thousands of unknowns are solved by the conjugate gradient method, without forming the large coefficient matrix explicitly. This avoids the complicated data management schemes to store such a large coefficient matrix. Three finite-element computer programs: FEM-LINEAR, FEM-QUADRATIC and FEM-CUBIC were developed, using the linear, quadratic, and cubic box-shape elements respectively. They are self-contained, using simple nodal labeling schemes, without the need for separate finite element mesh generating routines. The efficiency and accuracy of these computer programs are then compared among themselves, and with other computer codes. The cubic element model is not recommended for practical usage because it gives almost identical results as the quadratic model, but it requires considerably longer computation time. The linear model is less accurate than the quadratic model, but it requires much shorter computation time. For a large 3-D problem, the linear model is to be preferred since it gives acceptable accuracy. The quadratic model may be used if improved accuracy is desired

Sensitivity analyses of finite element method for estimating residual stress of dissimilar metal multi-pass weldment in nuclear power plant

Energy Technology Data Exchange (ETDEWEB)

Song, Tae Kwang; Bae, Hong Yeol; Kim, Yun Jae [Korea Unviersity, Seoul (Korea, Republic of); Lee, Kyoung Soo; Park, Chi Yong [Korea Electric Power Research Institute, Daejeon (Korea, Republic of)

2008-09-15

In nuclear power plants, ferritic low alloy steel components were connected with austenitic stainless steel piping system through alloy 82/182 butt weld. There have been incidents recently where cracking has been observed in the dissimilar metal weld. Alloy 82/182 is susceptible to primary water stress corrosion cracking. Weld-induced residual stress is main factor for crack growth. Therefore exact estimation of residual stress is important for reliable operating. This paper presents residual stress computation performed by 6'' safety and relief nozzle. Based on 2 dimensional and 3 dimensional finite element analyses, effect of welding variables on residual stress variation is estimated for sensitivity analysis.

Influence of the nuclear matter equation of state on the r-mode instability using the finite-range simple effective interaction

Science.gov (United States)

Pattnaik, S. P.; Routray, T. R.; Viñas, X.; Basu, D. N.; Centelles, M.; Madhuri, K.; Behera, B.

2018-05-01

The characteristic physical properties of rotating neutron stars under the r-mode oscillation are evaluated using the finite-range simple effective interaction. Emphasis is given on examining the influence of the stiffness of both the symmetric and asymmetric parts of the nuclear equation of state on these properties. The amplitude of the r-mode at saturation is calculated using the data of particular neutron stars from the considerations of ‘spin equilibrium’ and ‘thermal equilibrium’. The upper limit of the r-mode saturation amplitude is found to lie in the range 10‑8–10‑6, in agreement with the predictions of earlier work.

Finite Cycle Gibbs Measures on Permutations of

Science.gov (United States)

Armendáriz, Inés; Ferrari, Pablo A.; Groisman, Pablo; Leonardi, Florencia

2015-03-01

We consider Gibbs distributions on the set of permutations of associated to the Hamiltonian , where is a permutation and is a strictly convex potential. Call finite-cycle those permutations composed by finite cycles only. We give conditions on ensuring that for large enough temperature there exists a unique infinite volume ergodic Gibbs measure concentrating mass on finite-cycle permutations; this measure is equal to the thermodynamic limit of the specifications with identity boundary conditions. We construct as the unique invariant measure of a Markov process on the set of finite-cycle permutations that can be seen as a loss-network, a continuous-time birth and death process of cycles interacting by exclusion, an approach proposed by Fernández, Ferrari and Garcia. Define as the shift permutation . In the Gaussian case , we show that for each , given by is an ergodic Gibbs measure equal to the thermodynamic limit of the specifications with boundary conditions. For a general potential , we prove the existence of Gibbs measures when is bigger than some -dependent value.

[Nuclear theory: Annual report

International Nuclear Information System (INIS)

Iachello, F.; Alhassid, Y.; Kusnezov, D.

1991-01-01

This report discusses topics on : nuclear structure models; algebraic models of hadronic structure; nuclear reactions; hot rotating nuclei; chaos in nuclei; signatures of the quark-gluon plasma; hadronic spectroscopy; octupole collectivity in nuclei; finite-temperature methods for the many-body problem; and classical limit of algebraic hamiltonians

Simple, empirical approach to predict neutron capture cross sections from nuclear masses

Science.gov (United States)

Couture, A.; Casten, R. F.; Cakirli, R. B.

2017-12-01

Background: Neutron capture cross sections are essential to understanding the astrophysical s and r processes, the modeling of nuclear reactor design and performance, and for a wide variety of nuclear forensics applications. Often, cross sections are needed for nuclei where experimental measurements are difficult. Enormous effort, over many decades, has gone into attempting to develop sophisticated statistical reaction models to predict these cross sections. Such work has met with some success but is often unable to reproduce measured cross sections to better than 40 % , and has limited predictive power, with predictions from different models rapidly differing by an order of magnitude a few nucleons from the last measurement. Purpose: To develop a new approach to predicting neutron capture cross sections over broad ranges of nuclei that accounts for their values where known and which has reliable predictive power with small uncertainties for many nuclei where they are unknown. Methods: Experimental neutron capture cross sections were compared to empirical mass observables in regions of similar structure. Results: We present an extremely simple method, based solely on empirical mass observables, that correlates neutron capture cross sections in the critical energy range from a few keV to a couple hundred keV. We show that regional cross sections are compactly correlated in medium and heavy mass nuclei with the two-neutron separation energy. These correlations are easily amenable to predict unknown cross sections, often converting the usual extrapolations to more reliable interpolations. It almost always reproduces existing data to within 25 % and estimated uncertainties are below about 40 % up to 10 nucleons beyond known data. Conclusions: Neutron capture cross sections display a surprisingly strong connection to the two-neutron separation energy, a nuclear structure property. The simple, empirical correlations uncovered provide model-independent predictions of

Chiral ward-Takahashi identities at finite temperature and chiral phase transition in (2+1) dimensional chiral Gross-Neveu model

International Nuclear Information System (INIS)

Shen Kun; Qiu Zhongping

1993-01-01

Chiral Ward-Takahashi identities at finite temperature are derived in (2+1) dimensional chiral Gross-Neveu model. In terms of these identities, fermion mass generation and the mass spectra of bound states are investigate at finite temperature. Taking the fermion mass as an order parameter, the authors discuss the phase structure and chiral phase transition and obtain the critical temperature

Stress distributions in finite element analysis of concrete gravity dam ...

African Journals Online (AJOL)

Gravity dams are solid structures built of mass concrete material; they maintain their stability against the design loads from the geometric shape, the mass, and the strength of the concrete. The model was meshed with an 8-node biquadratic plane strain quadrilateral (CPE8R) elements, using ABAQUS, a finite element ...

The second RPA description for the decay of the one-phonon nuclear collective states at finite temperature

International Nuclear Information System (INIS)

Yannouleas, C.; Jang, S.

1986-01-01

The zero-temperature second RPA is generalized to finite temperatures through the use of the method of linearization of the equations of motion. After elimination of the quadruples, for low enough temperatures and within the subspace spanned by the doubles, a proper symmetrization yields an eigenvalue equation which exhibits formal properties like the simple RPA. From this second RPA eigenvalue equation, a closed formula for the spreading width of an isolated collective state is extracted. The second RPA can be recast in the form of a generalized collision term and be compared with the method of the Bethe-Salpeter equation for the two-body Green function. However, the second RPA method (and results) contrasts with the approach (and corresponding results) of the Boltzmann collision term, which is usually viewed as the appropriate agent for nuclear dissipation. (orig.)

A suitable low-order, eight-node tetrahedral finite element for solids

International Nuclear Information System (INIS)

Key, S.W.; Heinstein, M.S.; Stone, C.M.; Mello, F.J.; Blanford, M.L.; Budge, K.G.

1998-03-01

To use the all-tetrahedral mesh generation existing today, the authors have explored the creation of a computationally efficient eight-node tetrahedral finite element (a four-node tetrahedral finite element enriched with four mid-face nodal points). The derivation of the element's gradient operator, studies in obtaining a suitable mass lumping, and the element's performance in applications are presented. In particular they examine the eight-node tetrahedral finite element's behavior in longitudinal plane wave propagation, in transverse cylindrical wave propagation, and in simulating Taylor bar impacts. The element samples only constant strain states and, therefore, has 12 hour-glass modes. In this regard it bears similarities to the eight-node, mean-quadrature hexahedral finite element. Comparisons with the results obtained from the mean-quadrature eight-node hexahedral finite element and the four-node tetrahedral finite element are included. Given automatic all-tetrahedral meshing, the eight-node, constant-strain tetrahedral finite element is a suitable replacement for the eight-node hexahedral finite element in those cases where mesh generation requires an inordinate amount of user intervention and direction to obtain acceptable mesh properties

New discovery: Quantization of atomic and nuclear rest mass differences

International Nuclear Information System (INIS)

Gareev, F. A.; Zhidkova, I. E.

2007-01-01

We come to the conclusion that all atomic models based on either the Newton equation and the Kepler laws, or the Maxwell equations, or the Schrodinger and Dirac equations are in reasonable agreement with experimental data. We can only suspect that these equations are grounded on the same fundamental principle(s) which is (are) not known or these equations can be transformed into each other. We proposed a new mechanism of LENR: cooperative processes in the whole system - nuclei + atoms + condensed matter - nuclear reactions in plasma - can occur at smaller threshold energies than the corresponding ones on free constituents. We were able to quantize [1] phenomenologically the first time the differences between atomic and nuclear rest masses by the formula: ΔΔ M = n 1 /n 2 x 0.0076294 (in MeV/c 2 ), n i =1,2,3,... Note that this quantization rule is justified for atoms and nuclei with different A, N and Z and the nuclei and atoms represent a coherent synchronized open systems - a complex of coupled oscillators (resonators). The cooperative resonance synchronization mechanisms are responsible for explanation of how the electron volt world can influence on the nuclear mega electron volt world. It means that we created new possibilities for inducing and controlling nuclear reactions by atomic processes grounded on the fundamental low of physics - conservation law of energy. The results of these research fields can provide new ecologically pure mobile sources of energy independent from oil, gas and coal, new substances, and technologies. For example, this discovery gives us a simple and cheep method for utilization of nuclear waste. References [1] F.A. Gareev, I.E. Zhidkova, E-print arXiv Nucl-th/0610002 2006

Mean free path of nucleons in a Fermi gas at finite temperature

International Nuclear Information System (INIS)

Collins, M.T.; Griffin, J.J.

1980-01-01

The mean free path of a nucleon in a nuclear Fermi gas at finite temperature is calculated by utilizing the free nucleon-nucleon cross section modified to suppress final states excluded by the Pauli principle. The results agree with an earlier zero-temperature calculation but yield substantially smaller values than a previous finite-temperature analysis. The Fermi gas mean free paths are some two to four times shorter than those implied by phenomenological imaginary optical potentials, suggesting that the present Fermi gas model fails to adequately describe the physical processes determining the mean free path. Even so, the present results, taken as lower bounds on te mean free path, require temperatures of some 4.5 MeV before the mean free path of bound nucleons becomes as short as the nuclear diameter. It follows that very high excitation energies are prerequisite to any short mean free path assumption in nuclear heavy-ion collisions. (orig.)

Secondary-ion mass spectrometry: some applications in the analysis of nuclear material

International Nuclear Information System (INIS)

Christie, W.H.; Eby, R.E.; Warmack, R.J.; Landau, L.

1981-01-01

Secondary ion mass spectrometry (SIMS) has been shown to offer some significant advantages over conventional mass spectrometry for the analysis of radioactive samples. We have used SIMS for the rapid, accurate analysis of B, Li, Cs, U and Pu in various nuclear materials. In many instances, SIMS allows one to perform mass and isotopic analysis on samples that are not amenable to other mass spectrometric techniques (e.g., surface ionization, electron impact, etc.). The significant advantage that accrues from the use of SIMS for isotopic analysis of these materials is the cmplete elimination of any chemical sample preparation steps, and only sample dissolution is necessary for the application of isotope dilution methods for quantitative analysis. The high sensitivity of SIMS for B, Li, U and Pu makes it possible to analyze sufficiently small radioactive samples so that radiation is reduced to acceptable levels for safe handling. The precision of SIMS isotopic analysis for natural B samples is about 0.5% and is about 1% for natural Li samples

Measurement of particle size distribution and mass concentration of nuclear fuel aerosols

International Nuclear Information System (INIS)

Pickering, S.

1982-01-01

The particle size distribution and particle mass concentration of a nuclear fuel aerosol is measured by admitting the aerosol into a vertically-extending container, positioning an alpha particle detector within the container so that its window is horizontal and directed vertically, stopping the admission of aerosol into the container, detecting the alpha-activity of the particles of the aerosol sedimenting onto the detector window (for example in a series of equal time intervals until a constant level is reached), and converting the alpha-activity measurements into particle size distribution and/or particle mass concentration measurements. The detector is attached to a pivotted arm and by raising a counterweight can be lowered from the container for cleaning. (author)

Pion condensation and density isomerism in nuclear matter

International Nuclear Information System (INIS)

Hecking, P.; Weise, W.

1979-01-01

The possible existence of density isomers in nuclear matter, induced by pion condensation, is discussed; the nuclear equation of state is treated within the framework of the sigma model. Repulsive short-range baryon-baryon correlations, the admixture of Δ (1232) isobars and finite-range pion-baryon vertex form factors are taken into account. The strong dependence of density isomerism on the high density extrapolation of the equation of state for normal nuclear matter is also investigated. We find that, once finite range pion-baryon vertices are introduced, the appearance of density isomers becomes unlikely

Finite size effects and chiral symmetry breaking in quenched three-dimensional QED

International Nuclear Information System (INIS)

Hands, S.; Kogut, J.B.

1990-01-01

Finite size effects and the chiral condensate are studied in three-dimensional QED by the Lanczos and the conjugate-gradient algorithms. Very substantial finite size effects are observed, but studies on L 3 lattices with L ranging from 8 to 80 indicate the development of a non-vanishing chiral condensate in the continuum limit of the theory. The systematics of the finite size effects and the fermion mass dependence in the conjugate-gradient algorithm are clarified in this extensive study. (orig.)

Nuclear electric dipole moment with relativistic effects in Xe and Hg atoms

International Nuclear Information System (INIS)

Oshima, Sachiko; Fujita, Takehisa; Asaga, Tomoko

2007-01-01

The atomic electric dipole moment (EDM) is evaluated by considering the relativistic effects as well as nuclear finite size effects in Xe and Hg atomic systems. Due to Schiff's theorem, the first order perturbation energy of EDM is canceled out by the second order perturbation energy for the point nucleus. The nuclear finite size effects arising from the intermediate atomic excitations may be finite for deformed nucleus but it is extremely small. The finite size contribution of the intermediate nuclear excitations in the second order perturbation energy is completely canceled by the third order perturbation energy. As the results, the finite contribution to the atomic EDM comes from the first order perturbation energy of relativistic effects, and it amounts to around 0.3 and 0.4 percents of the neutron EDM d n for Xe and Hg, respectively, though the calculations are carried out with a simplified single-particle nuclear model. From this relation in Hg atomic system, we can extract the neutron EDM which is found to be just comparable with the direct neutron EDM measurement

An unstructured-mesh finite-volume MPDATA for compressible atmospheric dynamics

International Nuclear Information System (INIS)

Kühnlein, Christian; Smolarkiewicz, Piotr K.

2017-01-01

An advancement of the unstructured-mesh finite-volume MPDATA (Multidimensional Positive Definite Advection Transport Algorithm) is presented that formulates the error-compensative pseudo-velocity of the scheme to rely only on face-normal advective fluxes to the dual cells, in contrast to the full vector employed in previous implementations. This is essentially achieved by expressing the temporal truncation error underlying the pseudo-velocity in a form consistent with the flux-divergence of the governing conservation law. The development is especially important for integrating fluid dynamics equations on non-rectilinear meshes whenever face-normal advective mass fluxes are employed for transport compatible with mass continuity—the latter being essential for flux-form schemes. In particular, the proposed formulation enables large-time-step semi-implicit finite-volume integration of the compressible Euler equations using MPDATA on arbitrary hybrid computational meshes. Furthermore, it facilitates multiple error-compensative iterations of the finite-volume MPDATA and improved overall accuracy. The advancement combines straightforwardly with earlier developments, such as the nonoscillatory option, the infinite-gauge variant, and moving curvilinear meshes. A comprehensive description of the scheme is provided for a hybrid horizontally-unstructured vertically-structured computational mesh for efficient global atmospheric flow modelling. The proposed finite-volume MPDATA is verified using selected 3D global atmospheric benchmark simulations, representative of hydrostatic and non-hydrostatic flow regimes. Besides the added capabilities, the scheme retains fully the efficacy of established finite-volume MPDATA formulations.

An unstructured-mesh finite-volume MPDATA for compressible atmospheric dynamics

Energy Technology Data Exchange (ETDEWEB)

Kühnlein, Christian, E-mail: christian.kuehnlein@ecmwf.int; Smolarkiewicz, Piotr K., E-mail: piotr.smolarkiewicz@ecmwf.int

2017-04-01

An advancement of the unstructured-mesh finite-volume MPDATA (Multidimensional Positive Definite Advection Transport Algorithm) is presented that formulates the error-compensative pseudo-velocity of the scheme to rely only on face-normal advective fluxes to the dual cells, in contrast to the full vector employed in previous implementations. This is essentially achieved by expressing the temporal truncation error underlying the pseudo-velocity in a form consistent with the flux-divergence of the governing conservation law. The development is especially important for integrating fluid dynamics equations on non-rectilinear meshes whenever face-normal advective mass fluxes are employed for transport compatible with mass continuity—the latter being essential for flux-form schemes. In particular, the proposed formulation enables large-time-step semi-implicit finite-volume integration of the compressible Euler equations using MPDATA on arbitrary hybrid computational meshes. Furthermore, it facilitates multiple error-compensative iterations of the finite-volume MPDATA and improved overall accuracy. The advancement combines straightforwardly with earlier developments, such as the nonoscillatory option, the infinite-gauge variant, and moving curvilinear meshes. A comprehensive description of the scheme is provided for a hybrid horizontally-unstructured vertically-structured computational mesh for efficient global atmospheric flow modelling. The proposed finite-volume MPDATA is verified using selected 3D global atmospheric benchmark simulations, representative of hydrostatic and non-hydrostatic flow regimes. Besides the added capabilities, the scheme retains fully the efficacy of established finite-volume MPDATA formulations.

Multidimensional Schrödinger Equation and Spectral Properties of Heavy-Quarkonium Mesons at Finite Temperature

Directory of Open Access Journals (Sweden)

M. Abu-Shady

2016-01-01

Full Text Available The N-radial Schrödinger equation is analytically solved at finite temperature. The analytic exact iteration method (AEIM is employed to obtain the energy eigenvalues and wave functions for all states n and l. The application of present results to the calculation of charmonium and bottomonium masses at finite temperature is also presented. The behavior of the charmonium and bottomonium masses is in qualitative agreement with other theoretical methods. We conclude that the solution of the Schrödinger equation plays an important role at finite temperature that the analysis of the quarkonium states gives a key input to quark-gluon plasma diagnostics.

Finite temperature effects in Bose-Einstein condensed dark matter halos

International Nuclear Information System (INIS)

Harko, Tiberiu; Madarassy, Enikö J.M.

2012-01-01

Once the critical temperature of a cosmological boson gas is less than the critical temperature, a Bose-Einstein Condensation process can always take place during the cosmic history of the universe. Zero temperature condensed dark matter can be described as a non-relativistic, Newtonian gravitational condensate, whose density and pressure are related by a barotropic equation of state, with barotropic index equal to one. In the present paper we analyze the effects of the finite dark matter temperature on the properties of the dark matter halos. We formulate the basic equations describing the finite temperature condensate, representing a generalized Gross-Pitaevskii equation that takes into account the presence of the thermal cloud. The static condensate and thermal cloud in thermodynamic equilibrium is analyzed in detail, by using the Hartree-Fock-Bogoliubov and Thomas-Fermi approximations. The condensed dark matter and thermal cloud density and mass profiles at finite temperatures are explicitly obtained. Our results show that when the temperature of the condensate and of the thermal cloud are much smaller than the critical Bose-Einstein transition temperature, the zero temperature density and mass profiles give an excellent description of the dark matter halos. However, finite temperature effects may play an important role in the early stages of the cosmological evolution of the dark matter condensates

Finite-size scaling theory and quantum hamiltonian Field theory: the transverse Ising model

International Nuclear Information System (INIS)

Hamer, C.J.; Barber, M.N.

1979-01-01

Exact results for the mass gap, specific heat and susceptibility of the one-dimensional transverse Ising model on a finite lattice are generated by constructing a finite matrix representation of the Hamiltonian using strong-coupling eigenstates. The critical behaviour of the limiting infinite chain is analysed using finite-size scaling theory. In this way, excellent estimates (to within 1/2% accuracy) are found for the critical coupling and the exponents α, ν and γ

Multiple nucleon transfer in damped nuclear collisions. [Lectures, mass charge, and linear and angular momentum transport

Energy Technology Data Exchange (ETDEWEB)

Randrup, J.

1979-07-01

This lecture discusses a theory for the transport of mass, charge, linear, and angular momentum and energy in damped nuclear collisions, as induced by multiple transfer of individual nucleons. 11 references.

Properties of Localized Protons in Neutron Star Matter at Finite Temperatures

Science.gov (United States)

Szmaglinski, A.; Kubis, S.; Wójcik, W.

2014-02-01

We study properties of the proton component of neutron star matter for realistic nuclear models. Vanishing of the nuclear symmetry energy implies proton-neutron separation in dense nuclear matter. Protons which form admixture tend to be localized in potential wells. Here, we extend the description of proton localization to finite temperatures. It appears that the protons are still localized at temperatures typical for hot neutron stars. That fact has important astrophysical consequences. Moreover, the temperature inclusion leads to unexpected results for the behavior of the proton localized state.

Generalized multiscale finite element method. Symmetric interior penalty coupling

KAUST Repository

Efendiev, Yalchin R.; Galvis, Juan; Lazarov, Raytcho D.; Moon, M.; Sarkis, Marcus V.

2013-01-01

Motivated by applications to numerical simulations of flows in highly heterogeneous porous media, we develop multiscale finite element methods for second order elliptic equations. We discuss a multiscale model reduction technique in the framework of the discontinuous Galerkin finite element method. We propose two different finite element spaces on the coarse mesh. The first space is based on a local eigenvalue problem that uses an interior weighted L2-norm and a boundary weighted L2-norm for computing the "mass" matrix. The second choice is based on generation of a snapshot space and subsequent selection of a subspace of a reduced dimension. The approximation with these multiscale spaces is based on the discontinuous Galerkin finite element method framework. We investigate the stability and derive error estimates for the methods and further experimentally study their performance on a representative number of numerical examples. © 2013 Elsevier Inc.

Generalized multiscale finite element method. Symmetric interior penalty coupling

KAUST Repository

Efendiev, Yalchin R.

2013-12-01

Motivated by applications to numerical simulations of flows in highly heterogeneous porous media, we develop multiscale finite element methods for second order elliptic equations. We discuss a multiscale model reduction technique in the framework of the discontinuous Galerkin finite element method. We propose two different finite element spaces on the coarse mesh. The first space is based on a local eigenvalue problem that uses an interior weighted L2-norm and a boundary weighted L2-norm for computing the "mass" matrix. The second choice is based on generation of a snapshot space and subsequent selection of a subspace of a reduced dimension. The approximation with these multiscale spaces is based on the discontinuous Galerkin finite element method framework. We investigate the stability and derive error estimates for the methods and further experimentally study their performance on a representative number of numerical examples. © 2013 Elsevier Inc.

Mass and Elite Views on Nuclear Security: US National Security Surveys 1993-1999

Energy Technology Data Exchange (ETDEWEB)

HERRON,KERRY G.; JENKINS-SMITH,HANK C.; HUGHES,SCOTT D.

2000-06-01

This is the fourth report in an ongoing series of studies examining how US perspectives about nuclear security are evolving in the post-Cold War era. In Volume 1 the authors present findings from a nationwide telephone survey of randomly selected members of the US general public conducted from 13 September to 14 October 1999. Results are compared to findings from previous surveys in this series conducted in 1993, 1995, and 1997, and trends are analyzed. Key areas of investigation reported in Volume 1 include evolving perceptions of nuclear weapons risks and benefits, preferences for related policy and spending issues, and views about three emerging issue areas: deterrent utility of precision guided munitions; response options to attacks in which mass casualty weapons are used; and expectations about national missile defenses. In this volume they relate respondent beliefs about nuclear security to perceptions of nuclear risks and benefits and to policy preferences. They develop causal models to partially explain key preferences, and they employ cluster analysis to group respondents into four policy relevant clusters characterized by similar views and preferences about nuclear security within each cluster. Systematic links are found among respondent demographic characteristics, perceptions of nuclear risks and benefits, policy beliefs, and security policy and spending preferences. In Volume 2 they provide analysis of in-depth interviews with fifty members of the US security policy community.

Mass and Elite Views on Nuclear Security: US National Security Surveys 1993-1999

International Nuclear Information System (INIS)

Herron, Kerry G.; Jenkins-Smith, Hank C.; Hughes, Scott D.

2000-01-01

This is the fourth report in an ongoing series of studies examining how US perspectives about nuclear security are evolving in the post-Cold War era. In Volume 1 the authors present findings from a nationwide telephone survey of randomly selected members of the US general public conducted from 13 September to 14 October 1999. Results are compared to findings from previous surveys in this series conducted in 1993, 1995, and 1997, and trends are analyzed. Key areas of investigation reported in Volume 1 include evolving perceptions of nuclear weapons risks and benefits, preferences for related policy and spending issues, and views about three emerging issue areas: deterrent utility of precision guided munitions; response options to attacks in which mass casualty weapons are used; and expectations about national missile defenses. In this volume they relate respondent beliefs about nuclear security to perceptions of nuclear risks and benefits and to policy preferences. They develop causal models to partially explain key preferences, and they employ cluster analysis to group respondents into four policy relevant clusters characterized by similar views and preferences about nuclear security within each cluster. Systematic links are found among respondent demographic characteristics, perceptions of nuclear risks and benefits, policy beliefs, and security policy and spending preferences. In Volume 2 they provide analysis of in-depth interviews with fifty members of the US security policy community

Weapons of mass destruction: Overview of the CBRNEs (Chemical, Biological, Radiological, Nuclear, and Explosives).

Science.gov (United States)

Prockop, Leon D

2006-11-01

The events of September 11, 2001, made citizens of the world acutely aware of disasters consequent to present-day terrorism. This is a war being waged for reasons obscure to many of its potential victims. The term "NBCs" was coined in reference to terrorist weapons of mass destruction, i.e., nuclear, biological and chemical. The currently accepted acronym is "CBRNE" which includes Chemical, Biological, Radiological, Nuclear, and Explosive weapons. Non-nuclear explosives are the most common terrorist weapon now in use. Nuclear and radiological weapons are beyond the scope of this publication, which focuses on the "CBEs", i.e. chemical, biological and explosive weapons. Although neurologists will not be the first responders to CBEs, they must know about the neurological effects in order to provide diagnosis and treatment to survivors. Neurological complications of chemical, biological and explosive weapons which have or may be used by terrorists are reviewed by international experts in this publication. Management and treatment profiles are outlined.

Chiral symmetry breaking in finite quantum electrodynamics

International Nuclear Information System (INIS)

Montero, J.C.; Pleitez, V.

1987-01-01

The dynamical breakdown of chiral symmetry in a finite Abelian gauge theory using a variational approach for the effective potential for composite operators is discussed. It is shown that, at least in a variational approach, the fermion either remains massless or gets a dynamical mass for every non-zero coupling constant. (Author) [pt

Chemical, mass spectrometric, and spectrochemical analysis of nuclear-grade mixed oxides [(U,Pu)O2

International Nuclear Information System (INIS)

Anon.

1981-01-01

Mixed oxide, a mixture of uranium and plutonium oxides, is used as a nuclear-reactor fuel in the form of pellets. The plutonium content may be up to 10 wt %, and the diluent uranium may be of any U-235 enrichment. In order to be suitable for use as a nuclear fuel, the material must meet certain criteria for combined uranium and plutonium content, effective fissile content, and impurity content. Analytical procedures used to determine if mixed oxides comply with specifications are: uranium by controlled-potential coulometry; plutonium by controlled-potential coulometry; plutonium by amperometric titration with iron (II); nitrogen by distillation spectrophotometry using Nessler reagent; carbon (total) by direct combustion-thermal-conductivity; total chlorine and fluorine by pyrohydrolysis; sulfur by distillation-spectrophotometry; moisture by the coulometric, electrolytic moisture analyzer; isotopic composition by mass spectrometry; rare earths by copper spark spectroscopy; trace impurities by carrier distillation spectroscopy; impurities by spark-source mass spectrography; total gas in reactor-grade mixed dioxide pellets; tungsten by dithiol-spectrophotometry; rare earth elements by spectroscopy; plutonium-238 isotopic abundance by alpha spectrometry; uranium and plutonium isotopic analysis by mass spectrometry; oxygen-to-metal atom ratio by gravimetry

Finite-temperature phase structure of lattice QCD with Wilson quark action

International Nuclear Information System (INIS)

Aoki, S.; Ukawa, A.; Umemura, T.

1996-01-01

The long-standing issue of the nature of the critical line of lattice QCD with the Wilson quark action at finite temperatures, defined to be the line of vanishing pion screening mass, and its relation to the line of finite-temperature chiral transition is examined. Presented are both analytical and numerical evidence that the critical line forms a cusp at a finite gauge coupling, and that the line of chiral transition runs past the tip of the cusp without touching the critical line. Implications on the continuum limit and the flavor dependence of chiral transition are discussed. copyright 1996 The American Physical Society

A suitable low-order, eight-node tetrahedral finite element for solids

Energy Technology Data Exchange (ETDEWEB)

Key, S.W.; Heinstein, M.S.; Stone, C.M.; Mello, F.J.; Blanford, M.L.; Budge, K.G.

1998-03-01

To use the all-tetrahedral mesh generation existing today, the authors have explored the creation of a computationally efficient eight-node tetrahedral finite element (a four-node tetrahedral finite element enriched with four mid-face nodal points). The derivation of the element`s gradient operator, studies in obtaining a suitable mass lumping, and the element`s performance in applications are presented. In particular they examine the eight-node tetrahedral finite element`s behavior in longitudinal plane wave propagation, in transverse cylindrical wave propagation, and in simulating Taylor bar impacts. The element samples only constant strain states and, therefore, has 12 hour-glass modes. In this regard it bears similarities to the eight-node, mean-quadrature hexahedral finite element. Comparisons with the results obtained from the mean-quadrature eight-node hexahedral finite element and the four-node tetrahedral finite element are included. Given automatic all-tetrahedral meshing, the eight-node, constant-strain tetrahedral finite element is a suitable replacement for the eight-node hexahedral finite element in those cases where mesh generation requires an inordinate amount of user intervention and direction to obtain acceptable mesh properties.

Stress analysis of heated concrete using finite elements

International Nuclear Information System (INIS)

Majumdar, P.; Gupta, A.; Marchertas, A.

1994-01-01

Described is a finite element analysis of concrete, which is subjected to rapid heating. Using thermal mass transport calculation, the moisture content, temperature and pore pressure distribution over space and time is obtained first. From these effects, stress at various points of the concrete are computed using the finite element method. Contribution to the stress formulation comes from three components, namely the thermal expansion, pore pressure, and the shrinkage of concrete due to moisture loss (from dehydration). The material properties of concrete are assumed to be homogeneous, elastic, and cracking is not taken into consideration. (orig.)

Rock mass modification around a nuclear waste repository in welded tuff

International Nuclear Information System (INIS)

Mack, M.G.; Brandshaug, T.; Brady, B.H.

1989-08-01

This report presents the results of numerical analyses to estimate the extent of rock mass modification resulting from the presence of a High Level Waste (HLW) repository. Changes in rock mass considered are stresses and joint deformations resulting from disposal room excavation and thermal efffects induced by the heat generated by nuclear waste. rock properties and site conditions are taken from the Site Characterization Plan Conceptual Design Report for the potential repository site at Yucca Mountain, Nevada. Analyses were conducted using boundary element and distinct element methods. Room-scale models and repository-scale models were investigated for up to 500 years after waste emplacement. Results of room-scale analyses based on the thermoelastic boundary element model indicate that a zone of modified rock develops around the disposal rooms for both vertical and horizontal waste emplacement. This zone is estimated to extend a distance of roughly two room diameters from the room surface. Results from the repository-scale model, which are based on the thermoelastic boundary element model and the distinct element model, indicate a zone with modified rock mass properties starting approximately 100 m above and below the repository, with a thickness of approximately 200 m above and 150 m below the repository. Slip-prone subhorizontal features are shown to have a substantial effect on rock mass response. The estimates of rock mass modification reflect uncertainties and simplifying assumptions in the models. 32 refs., 57 figs., 1 tab

A stabilized second-order time accurate finite element formulation for incompressible viscous flow with heat transfer

International Nuclear Information System (INIS)

Curi, Marcos Filardy

2011-01-01

In view of the problem of global warming and the search for clean energy sources, a worldwide expansion on the use of nuclear energy is foreseen. Thus, the development of science and technology regarding nuclear power plants is essential, in particular in the field of reactor engineering. Fluid mechanics and heat transfer play an important role in the development of nuclear reactors. Computational Fluid Mechanics (CFD) is becoming ever more important in the optimization of cost and safety of the designs. This work presents a stabilized second-order time accurate finite element formulation for incompressible flows with heat transfer. A second order time discretization precedes a spatial discretization using finite elements. The terms that stabilize the finite element method arise naturally from the discretization process, rather than being introduced a priori in the variational formulation. The method was implemented in the program 'ns n ew s olvec2d av 2 M PI' written in FORTRAN90, developed in the Parallel Computing Laboratory at the Institute of Nuclear Engineering (LCP/IEN). Numerical solutions of some representative examples, including free, mixed and forced convection, demonstrate that the proposed stabilized formulation attains very good agreement with experimental and computational results available in the literature. (author)

Standard test methods for chemical and mass spectrometric analysis of nuclear-grade gadolinium oxide (Gd2O3) powder

CERN Document Server

American Society for Testing and Materials. Philadelphia

2006-01-01

1.1 These test methods cover procedures for the chemical and mass spectrometric analysis of nuclear-grade gadolinium oxide powders to determine compliance with specifications. 1.2 The analytical procedures appear in the following order: Sections Carbon by Direct CombustionThermal Conductivity C1408 Test Method for Carbon (Total) in Uranium Oxide Powders and Pellets By Direct Combustion-Infrared Detection Method Total Chlorine and Fluorine by Pyrohydrolysis Ion Selective Electrode C1502 Test Method for Determination of Total Chlorine and Fluorine in Uranium Dioxide and Gadolinium Oxide Loss of Weight on Ignition 7-13 Sulfur by CombustionIodometric Titration Impurity Elements by a Spark-Source Mass Spectrographic C761 Test Methods for Chemical, Mass Spectrometric, Spectrochemical,Nuclear, and Radiochemical Analysis of Uranium Hexafluoride C1287 Test Method for Determination of Impurities In Uranium Dioxide By Inductively Coupled Plasma Mass Spectrometry Gadolinium Content in Gadolinium Oxid...

On the reliability of finite element solutions

International Nuclear Information System (INIS)

Prasad, K.S.R.K.

1975-01-01

The extent of reliability of the finite element method for analysis of nuclear reactor structures, and that of reactor vessels in particular and the need for the engineer to guard against the pitfalls that may arise out of both physical and mathematical models have been high-lighted. A systematic way of checking the model to obtain reasonably accurate solutions is presented. Quite often sophisticated elements are suggested for specific design and stress concentration problems. The desirability or otherwise of these elements, their scope and utility vis-a-vis the use of large stack of conventional elements are discussed from the view point of stress analysts. The methods of obtaining a check on the reliability of the finite element solutions either through modelling changes or an extrapolation technique are discussed. (author)

Finite Element Analysis of Circular Plate using SolidWorks

International Nuclear Information System (INIS)

Kang, Yeo Jin; Jhung, Myung Jo

2011-01-01

Circular plates are used extensively in mechanical engineering for nuclear reactor internal components. The examples in the reactor vessel internals are upper guide structure support plate, fuel alignment plate, lower support plate etc. To verify the structural integrity of these plates, the finite element analyses are performed, which require the development of the finite element model. Sometimes it is very costly and time consuming to make the model especially for the beginners who start their engineering job for the structural analysis, necessitating a simple method to develop the finite element model for the pursuing structural analysis. Therefore in this study, the input decks are generated for the finite element analysis of a circular plate as shown in Fig. 1, which can be used for the structural analysis such as modal analysis, response spectrum analysis, stress analysis, etc using the commercial program Solid Works. The example problems are solved and the results are included for analysts to perform easily the finite element analysis of the mechanical plate components due to various loadings. The various results presented in this study would be helpful not only for the benchmark calculations and results comparisons but also as a part of the knowledge management for the future generation of young designers, scientists and computer analysts

Accelerator Mass Spectrometry at the National Institute of Nuclear Physics and Engineering in Bucharest

International Nuclear Information System (INIS)

Stan-Sion, C.; Catana, D.; Plostinaru, D.; Radulescu, M.; Enachescu, M.; Ivascu, M.; Marinescu, L.; Dima, R.

2000-01-01

The Accelerator Mass Spectrometry (AMS) is today the experimental physical method capable to measure the lowest concentration of a particular nuclide in a sample material. Ratios of radionuclides in the range 10 -13 - 10 -15 are normally measured with this technique, corresponding to a sensitivity which makes possible the detection of only 1 Atom in a surrounding material of about 1 Million of Billions of other Atoms. Thus, the AMS has advanced the art of Classical Mass Spectrometry (sensitivity 10 -11 ) to a sensitivity which allows for the first time the performance of special applications in environmental physics, medicine, pharmacology, geology, archaeology, measurements of radio nuclides in the Earth's atmosphere produced by cosmic-rays or by nuclear power plants, applications in astrophysics and in nuclear physics.An Accelerator Mass Spectrometry facility was constructed at the FN - 8 MV tandem accelerator of the National Institute of Physics and Nuclear Engineering . The construction was possible in the frame of a co-operation with the Technical University Munich and with financial support from IAEA-Vienna. It represents the first experimental set-up of this type in the large geographical area of Eastern Europe. The main components of the facility are: the ion injector deck, the AMS beam line and the detector systems. The injector deck is polarized at 50 kV and contains the high current sputtering ion source (spherical ionizer) followed, for beam transport, by electrostatic devices (single lenses, steerers, quadrupole lenses) a double focussing, 90 angle analyzing magnet (Danfysik), a pre-acceleration tube (NEC) and several diagnose and defining elements. The AMS samples are placed in an eight-stack magazine attached to the ion source. On the exit side of the tandem accelerator tank, a velocity filter and the particle detection system are mounted. The beam line, on the high-energy side, is optically achromatic and contains two 90 angle analyzing magnets of

Nuclear fission: What have we learned in 50 years?

International Nuclear Information System (INIS)

Vandenbosch, R.

1989-01-01

Nuclear fission has captured the imagination of chemists and physicists for half a century now. There are several reasons for this. One of course is that it represents the most drastic rearrangement of nuclear matter known, challenged only recently by collisions induced by very heavy ions. Another is that both statistical and dynamical features come into play. Perhaps one of the most compelling reasons is its never-ending capacity to surprise us: asymmetric mass distributions, the sawtooth dependence of neutron yields in fragment mass, spontaneously fissioning isomers and intermediate structure resonances. Finally, and perhaps most importantly, fission is a rich laboratory within which one can explore the delicate interplay between the macroscopic aspects of bulk nuclear matter and the quantal effects of a finite number of Fermions. It will of course be impossible for me to cover all aspects of fission. I have chosen a limited number of topics to cover, with particular topics being chosen either because the have been associated with persistent puzzles in fission or because they have, or hopefully will, tell us something special about how nuclei behave. After a brief historical note, I organize these topics sequentially according to the various stages of the fission process, starting first with the probability for fission to occur and ending with scission phenomena. 56 refs., 11 figs

Approximate approaches to the one-dimensional finite potential well

International Nuclear Information System (INIS)

Singh, Shilpi; Pathak, Praveen; Singh, Vijay A

2011-01-01

The one-dimensional finite well is a textbook problem. We propose approximate approaches to obtain the energy levels of the well. The finite well is also encountered in semiconductor heterostructures where the carrier mass inside the well (m i ) is taken to be distinct from mass outside (m o ). A relevant parameter is the mass discontinuity ratio β = m i /m o . To correctly account for the mass discontinuity, we apply the BenDaniel-Duke boundary condition. We obtain approximate solutions for two cases: when the well is shallow and when the well is deep. We compare the approximate results with the exact results and find that higher-order approximations are quite robust. For the shallow case, the approximate solution can be expressed in terms of a dimensionless parameter σ l = 2m o V 0 L 2 /ℎ 2 (or σ = β 2 σ l for the deep case). We show that the lowest-order results are related by a duality transform. We also discuss how the energy upscales with L (E∼1/L γ ) and obtain the exponent γ. Exponent γ → 2 when the well is sufficiently deep and β → 1. The ratio of the masses dictates the physics. Our presentation is pedagogical and should be useful to students on a first course on elementary quantum mechanics or low-dimensional semiconductors.

Conditions for equivalence of statistical ensembles in nuclear multifragmentation

International Nuclear Information System (INIS)

Mallik, Swagata; Chaudhuri, Gargi

2012-01-01

Statistical models based on canonical and grand canonical ensembles are extensively used to study intermediate energy heavy-ion collisions. The underlying physical assumption behind canonical and grand canonical models is fundamentally different, and in principle agree only in the thermodynamical limit when the number of particles become infinite. Nevertheless, we show that these models are equivalent in the sense that they predict similar results if certain conditions are met even for finite nuclei. In particular, the results converge when nuclear multifragmentation leads to the formation of predominantly nucleons and low mass clusters. The conditions under which the equivalence holds are amenable to present day experiments.

Modified random phase approximation for multipole excitations at finite temperature

International Nuclear Information System (INIS)

Nguyen Dinh Dang

1991-01-01

The modified finite temperature random phase approximation (modified FT-RPA) has been constructed with taking the influence of thermostat on the structure of quansiparticles into account. The modified FT-RPA linear response for electric quadrupole (λ π = 2 + ) and octupole (λ π = 3 - ) excitations in 5 8Ni has been calculated as a function of the nuclear temperature. As compared to the conventional FT-RPA the modified FT-RPA has given a stronger spreading for the strength distribution of quandrupole excitations at finite temperature T ≤ 3MeV. (author). 22 refs; 4 figs; 2 tabs

Condensation phenomena in two-flavor scalar QED at finite chemical potential

CERN Document Server

Schmidt, Alexander; Gattringer, Christof

2014-01-01

We study condensation in two-flavored, scalar QED with non-degenerate masses at finite chemical potential. The conventional formulation of the theory has a sign problem at finite density which can be solved using an exact reformulation of the theory in terms of dual variables. We perform a Monte Carlo simulation in the dual representation and observe a condensation at a critical chemical potential $\\mu_c$. After determining the low-energy spectrum of the theory we try to establish a connection between $\\mu_c$ and the mass of the lightest excitation of the system, which are naively expected to be equal. It turns out, however, that the relation of the critical chemical potential to the mass spectrum in this case is non-trivial: Taking into account the form of the condensate and making some simplifying assumptions we suggest an adequate explanation which is supported by numerical results.

Chiral symmetry and finite temperature effects in quantum theories

International Nuclear Information System (INIS)

Larsen, Aa.

1987-01-01

A computer simulation of the harmonic oscillator at finite temperature has been carried out, using the Monte Carlo Metropolis algorithm. Accurate results for the energy and fluctuations have been obtained, with special attention to the manifestation of the temperature effects. Varying the degree of symmetry breaking, the finite temperature behaviour of the asymmetric linear model in a linearized mean field approximation has been studied. In a study of the effects of chiral symmetry on baryon mass splittings, reasonable agreement with experiment has been obtained in a non-relativistic harmonic oscillator model

Radiocarbon Mass Balance for a Magnox Nuclear Power Station

International Nuclear Information System (INIS)

Metcalfe, M.P.; Mills, R.W.

2016-01-01

Nuclear power generation in the United Kingdom is based principally on graphite-moderated gas-cooled reactors. The mass of irradiated graphite associated with these reactors, including material from associated experimental, prototype and production reactors, exceeds 96,000 tonnes. One of the principal long-lived radionuclides produced during graphite irradiation is radiocarbon (C-14), which has a half-life of 5730 ± 40 years. Decommissioning and graphite waste management strategies must take account of this radionuclide. In order to identify appropriate options for addressing the potential hazard of C-14, it is important that the production processes are understood and the distributions and concentrations of C-14 are characterised. In fact, C-14 precursors and their activation processes are well-known. However, there is ongoing debate over the relative importance of different C-14 precursors, which will determine the location of C-14 within graphite components and hence its mobility/response to treatment. A generally held misconception concerning C-14 in irradiated graphite is that generic statements can be made about its precursors and their location. C-14 location and activities will depend upon the composition of the original manufactured graphite (raw materials, impurities), the chemical environment of the graphite during service and the irradiation history of the graphite. So, while there may be some similarities across, for example, carbon dioxide cooled graphite moderated designs (Magnox, AGR, UNGG), any informed assessment of a core’s C-14 inventory would require more-precise characterisation. The analysis presented here focuses on a UK Magnox reactor core, Reactor 1 at Wylfa Nuclear Power Station. The objective of the analysis is to present a full C-14 mass balance over a selected period of operation for which there are accurate C-14 discharge records. The analysis presented here provides the first assessment of the principal C-14 activation pathways

Effective mass of a #betta#-particle in nuclear matter and OBE #betta#-n interactions

International Nuclear Information System (INIS)

Bando, Hiroharu; Nagata, Sinobu.

1982-01-01

The effective mass of a lambda particle (M sub( lambda )*) in nuclear matter is investigated within the framework of the lowest-order Brueckner theory by employing the Nijmegen OBE lambda -N interaction model D and F. The non-locality mass (M tilde sub( lamda )) and the energy mass (anti M sub( lambda )) are evaluated and discussed in the light of the characteristics of the two models. In comparison with the model D, the model F yields smaller anti M sub( lambda ) and larger anti M sub( lamb da ) reflecting the stronger Majorana exchange force and the stronger lambda N- sigma N coupling tensor force. Final results of M sub( lambda )*/M sub( lambda ) are 0.85 for D and 0.79 for F. In view of the effective lambda mass inferred from observed properties of the single particle potential for lambda , the model D interaction seems to be more adequate. (author)

The Finite-Surface Method for incompressible flow: a step beyond staggered grid

Science.gov (United States)

Hokpunna, Arpiruk; Misaka, Takashi; Obayashi, Shigeru

2017-11-01

We present a newly developed higher-order finite surface method for the incompressible Navier-Stokes equations (NSE). This method defines the velocities as a surface-averaged value on the surfaces of the pressure cells. Consequently, the mass conservation on the pressure cells becomes an exact equation. The only things left to approximate is the momentum equation and the pressure at the new time step. At certain conditions, the exact mass conservation enables the explicit n-th order accurate NSE solver to be used with the pressure treatment that is two or four order less accurate without loosing the apparent convergence rate. This feature was not possible with finite volume of finite difference methods. We use Fourier analysis with a model spectrum to determine the condition and found that the range covers standard boundary layer flows. The formal convergence and the performance of the proposed scheme is compared with a sixth-order finite volume method. Finally, the accuracy and performance of the method is evaluated in turbulent channel flows. This work is partially funded by a research colloaboration from IFS, Tohoku university and ASEAN+3 funding scheme from CMUIC, Chiang Mai University.

Modification of the finite element heat and mass transfer code (FEHM) to model multicomponent reactive transport

International Nuclear Information System (INIS)

Viswanathan, H.S.

1996-08-01

The finite element code FEHMN, developed by scientists at Los Alamos National Laboratory (LANL), is a three-dimensional finite element heat and mass transport simulator that can handle complex stratigraphy and nonlinear processes such as vadose zone flow, heat flow and solute transport. Scientists at LANL have been developing hydrologic flow and transport models of the Yucca Mountain site using FEHMN. Previous FEHMN simulations have used an equivalent Kd model to model solute transport. In this thesis, FEHMN is modified making it possible to simulate the transport of a species with a rigorous chemical model. Including the rigorous chemical equations into FEHMN simulations should provide for more representative transport models for highly reactive chemical species. A fully kinetic formulation is chosen for the FEHMN reactive transport model. Several methods are available to computationally implement a fully kinetic formulation. Different numerical algorithms are investigated in order to optimize computational efficiency and memory requirements of the reactive transport model. The best algorithm of those investigated is then incorporated into FEHMN. The algorithm chosen requires for the user to place strongly coupled species into groups which are then solved for simultaneously using FEHMN. The complete reactive transport model is verified over a wide variety of problems and is shown to be working properly. The new chemical capabilities of FEHMN are illustrated by using Los Alamos National Laboratory's site scale model of Yucca Mountain to model two-dimensional, vadose zone 14 C transport. The simulations demonstrate that gas flow and carbonate chemistry can significantly affect 14 C transport at Yucca Mountain. The simulations also prove that the new capabilities of FEHMN can be used to refine and buttress already existing Yucca Mountain radionuclide transport studies

Storage of plutonium and nuclear power plant actinide waste in the form of critical-mass-free ceramics containing neutron poisons

Energy Technology Data Exchange (ETDEWEB)

Nadykto, B.A. [RFNC-VNIIEF, Nizhni Novgorod Region (Russian Federation)

2001-07-01

The nuclear weapons production has resulted in accumulation of a large quantity of plutonium and uranium highly enriched with uranium-235 isotope (many tons). The work under ISTC Project 332B-97 treated the issues of safe plutonium storage through making critical-mass-free plutonium oxide compositions with neutron poisons. This completely excludes immediate utilization (without chemical reprocessing) of retained plutonium in nuclear devices. It is therewith possible to locate plutonium most compactly in the storage facility, which would allow reduction in required storage areas and costs. The issues of the surplus weapon-grade plutonium management and utilization have been comprehensively studied in the recent decade. The issues are treated in multiple scientific publications, conferences, and seminars. At the same time, issues of nuclear power engineering actinide waste storage are studied no less extensively. The general issues are material radioactivity and energy release and nuclear accident hazards due to critical mass generation. Plutonium accumulated in nuclear power plant spent fuel is more accessible than weapon-grade plutonium and can become of higher and higher interest with time as its activity reduces, including as material for nuclear devices. The urgency of plutonium management is presently related not only to accumulation of surplus weapon-grade plutonium, but also to the fact that it is high time to decide what has to be done regarding reactor plutonium. Presently, the possibility of actinide separation from NPP spent nuclear fuel and compact underground burial separately from other (mainly fragment) activity is being considered. Actinide and neutron poison base critical-mass-free ceramic materials (similar to plutonium ceramics) may be useful for this burial method. (author)

Storage of plutonium and nuclear power plant actinide waste in the form of critical-mass-free ceramics containing neutron poisons

International Nuclear Information System (INIS)

Nadykto, B.A.

2001-01-01

The nuclear weapons production has resulted in accumulation of a large quantity of plutonium and uranium highly enriched with uranium-235 isotope (many tons). The work under ISTC Project 332B-97 treated the issues of safe plutonium storage through making critical-mass-free plutonium oxide compositions with neutron poisons. This completely excludes immediate utilization (without chemical reprocessing) of retained plutonium in nuclear devices. It is therewith possible to locate plutonium most compactly in the storage facility, which would allow reduction in required storage areas and costs. The issues of the surplus weapon-grade plutonium management and utilization have been comprehensively studied in the recent decade. The issues are treated in multiple scientific publications, conferences, and seminars. At the same time, issues of nuclear power engineering actinide waste storage are studied no less extensively. The general issues are material radioactivity and energy release and nuclear accident hazards due to critical mass generation. Plutonium accumulated in nuclear power plant spent fuel is more accessible than weapon-grade plutonium and can become of higher and higher interest with time as its activity reduces, including as material for nuclear devices. The urgency of plutonium management is presently related not only to accumulation of surplus weapon-grade plutonium, but also to the fact that it is high time to decide what has to be done regarding reactor plutonium. Presently, the possibility of actinide separation from NPP spent nuclear fuel and compact underground burial separately from other (mainly fragment) activity is being considered. Actinide and neutron poison base critical-mass-free ceramic materials (similar to plutonium ceramics) may be useful for this burial method. (author)

A Preliminary Model for Spacecraft Propulsion Performance Analysis Based on Nuclear Gain and Subsystem Mass-Power Balances

Science.gov (United States)

Chakrabarti, Suman; Schmidt, George R.; Thio, Y. C.; Hurst, Chantelle M.

1999-01-01

A preliminary model for spacecraft propulsion performance analysis based on nuclear gain and subsystem mass-power balances are presented in viewgraph form. For very fast missions with straight-line trajectories, it has been shown that mission trip time is proportional to the cube root of alpha. Analysis of spacecraft power systems via a power balance and examination of gain vs. mass-power ratio has shown: 1) A minimum gain is needed to have enough power for thruster and driver operation; and 2) Increases in gain result in decreases in overall mass-power ratio, which in turn leads to greater achievable accelerations. However, subsystem mass-power ratios and efficiencies are crucial: less efficient values for these can partially offset the effect of nuclear gain. Therefore, it is of interest to monitor the progress of gain-limited subsystem technologies and it is also possible that power-limited systems with sufficiently low alpha may be competitive for such ambitious missions. Topics include Space flight requirements; Spacecraft energy gain; Control theory for performance; Mission assumptions; Round trips: Time and distance; Trip times; Vehicle acceleration; and Minimizing trip times.

On finite larmor radius stabilization of Z-pinches

International Nuclear Information System (INIS)

Hellsten, T.

1982-12-01

Finite Larmor radius stabilization of Z-pinches is discussed. Stability criteria can be derived for a class of equilibria having constant mass and current density. The internal modes can be stabilized provided the line density not exceed a critical value of the order of 10 18 ions/m. (Author)

The current state and issues regarding communication from the nuclear energy industry to the mass media in Japan

International Nuclear Information System (INIS)

Tsuchida, Tatsuro; Kimura, Hiroshi

2011-01-01

The mass media has the potential to effect the utilization of nuclear power in Japan. In most cases journalists contact PR staff of the nuclear energy industry (hereinafter called 'the industry') to collect information about various events of nuclear energy. The industry is always ready to distribute related information and hold a press conference timely when necessary. In terms of the organizational structure for the PR activities each electric power company organizes the PR section in-house. The PR staff provides journalists with information on a daily basis. For the purpose of grasping the mass media's awareness, the author conducted interviews with 22 journalists who had experience in reporting news on nuclear energy subjects. The result showed that the journalists recognized the necessity of nuclear energy. The interviewees suggested that a proper press launch should be needed at just the right time especially in emergency situations and a press release should be more easily understandable. This interview showed that journalists considered the media reports as reflection of citizens' opinion. Most of the journalists realize that the influence of the media coverage should not be negligible and they acknowledge commutation between the two sides is gradually improved compared to before. (author)

Chiral thermodynamics of nuclear matter

International Nuclear Information System (INIS)

Fiorilla, Salvatore

2012-01-01

The equation of state of nuclear matter is calculated at finite temperature in the framework of in-medium chiral perturbation theory up to three-loop order. The dependence of its thermodynamic properties on the isospin-asymmetry is investigated. The chiral quark condensate is evaluated for symmetric nuclear matter. Its behaviour as a function of density and temperature sets important nuclear physics constraints for the QCD phase diagram.

Chiral thermodynamics of nuclear matter

Energy Technology Data Exchange (ETDEWEB)

Fiorilla, Salvatore

2012-10-23

The equation of state of nuclear matter is calculated at finite temperature in the framework of in-medium chiral perturbation theory up to three-loop order. The dependence of its thermodynamic properties on the isospin-asymmetry is investigated. The chiral quark condensate is evaluated for symmetric nuclear matter. Its behaviour as a function of density and temperature sets important nuclear physics constraints for the QCD phase diagram.

Characterization of spent nuclear fuels by an online combination of chromatographic and mass spectrometric techniques

International Nuclear Information System (INIS)

Guenther-Leopold, Ines; Wernli, Beat; Kopajtic, Zlatko

2003-01-01

The determination of the burn-up is one of the essential parts in post-irradiation examinations on nuclear fuel samples. In the frame of national and international research programs the analysis of the isotopic vectors of uranium, plutonium, neodymium and some other fission products and actinides was carried out in the Hot lab of the Paul Scherrer Institute in the last years by using high-performance liquid chromatography coupled online with an inductively coupled plasma quadrupole mass spectrometer. In the meantime a multicollector ICP-MS, suitable for high precision isotope ratio measurements, was installed within the Hot lab and has been used now in combination with a chromatographic separation system for the first time for burn-up determinations of nuclear fuel samples. The results of these investigations, a comparison of both methods with the classical technique for burn-up analyses (thermal ionization mass spectrometry), the advantages and limitations of the methods and the accuracy and precision of this type of analyses are presented in the paper. (author)

Finite elements methods in mechanics

CERN Document Server

Eslami, M Reza

2014-01-01

This book covers all basic areas of mechanical engineering, such as fluid mechanics, heat conduction, beams, and elasticity with detailed derivations for the mass, stiffness, and force matrices. It is especially designed to give physical feeling to the reader for finite element approximation by the introduction of finite elements to the elevation of elastic membrane. A detailed treatment of computer methods with numerical examples are provided. In the fluid mechanics chapter, the conventional and vorticity transport formulations for viscous incompressible fluid flow with discussion on the method of solution are presented. The variational and Galerkin formulations of the heat conduction, beams, and elasticity problems are also discussed in detail. Three computer codes are provided to solve the elastic membrane problem. One of them solves the Poisson’s equation. The second computer program handles the two dimensional elasticity problems, and the third one presents the three dimensional transient heat conducti...

Finite-size effects in the three-state quantum asymmetric clock model

International Nuclear Information System (INIS)

Gehlen, G. v.; Rittenberg, V.

1983-04-01

The one-dimensional quantum Hamiltonian of the asymmetric three-state clock model is studied using finite-size scaling. Various boundary conditions are considered on chains containing up to eight sites. We calculate the boundary of the commensurate phase and the mass gap index. The model shows an interesting finite-size dependence in connexion with the presence of the incommensurate phase indicating that for the infinite system there is no Lifshitz point. (orig.)

Meson spectral functions at finite temperature

International Nuclear Information System (INIS)

Wetzorke, I.; Karsch, F.; Laermann, E.; Petreczky, P.; Stickan, S.

2001-10-01

The Maximum Entropy Method provides a Bayesian approach to reconstruct the spectral functions from discrete points in Euclidean time. The applicability of the approach at finite temperature is probed with the thermal meson correlation function. Furthermore the influence of fuzzing/smearing techniques on the spectral shape is investigated. We present first results for meson spectral functions at several temperatures below and above T c . The correlation functions were obtained from quenched calculations with Clover fermions on large isotropic lattices of the size (24 - 64) 3 x 16. We compare the resulting pole masses with the ones obtained from standard 2-exponential fits of spatial and temporal correlation functions at finite temperature and in the vacuum. The deviation of the meson spectral functions from free spectral functions is examined above the critical temperature. (orig.)

Meson spectral functions at finite temperature

International Nuclear Information System (INIS)

Wetzorke, I.; Karsch, F.; Laermann, E.; Petreczky, P.; Stickan, S.

2002-01-01

The Maximum Entropy Method provides a Bayesian approach to reconstruct the spectral functions from discrete points in Euclidean time. The applicability of the approach at finite temperature is probed with the thermal meson correlation function. Furthermore the influence of fuzzing/smearing techniques on the spectral shape is investigated. We present first results for meson spectral functions at several temperatures below and above T c . The correlation functions were obtained from quenched calculations with Clover fermions on large isotropic lattices of the size (24 - 64) 3 x 16. We compare the resulting pole masses with the ones obtained from standard 2-exponential fits of spatial and temporal correlation functions at finite temperature and in the vacuum. The deviation of the meson spectral functions from free spectral functions is examined above the critical temperature

Meson spectral functions at finite temperature

Energy Technology Data Exchange (ETDEWEB)

Wetzorke, I.; Karsch, F.; Laermann, E.; Petreczky, P.; Stickan, S

2002-03-01

The Maximum Entropy Method provides a Bayesian approach to reconstruct the spectral functions from discrete points in Euclidean time. The applicability of the approach at finite temperature is probed with the thermal meson correlation function. Furthermore the influence of fuzzing/smearing techniques on the spectral shape is investigated. We present first results for meson spectral functions at several temperatures below and above T{sub c}. The correlation functions were obtained from quenched calculations with Clover fermions on large isotropic lattices of the size (24 - 64){sup 3} x 16. We compare the resulting pole masses with the ones obtained from standard 2-exponential fits of spatial and temporal correlation functions at finite temperature and in the vacuum. The deviation of the meson spectral functions from free spectral functions is examined above the critical temperature.

Meson spectral functions at finite temperature

Energy Technology Data Exchange (ETDEWEB)

Wetzorke, I.; Karsch, F.; Laermann, E.; Petreczky, P.; Stickan, S. [Bielefeld Univ. (Germany). Fakultaet fuer Physik

2001-10-01

The Maximum Entropy Method provides a Bayesian approach to reconstruct the spectral functions from discrete points in Euclidean time. The applicability of the approach at finite temperature is probed with the thermal meson correlation function. Furthermore the influence of fuzzing/smearing techniques on the spectral shape is investigated. We present first results for meson spectral functions at several temperatures below and above T{sub c}. The correlation functions were obtained from quenched calculations with Clover fermions on large isotropic lattices of the size (24 - 64){sup 3} x 16. We compare the resulting pole masses with the ones obtained from standard 2-exponential fits of spatial and temporal correlation functions at finite temperature and in the vacuum. The deviation of the meson spectral functions from free spectral functions is examined above the critical temperature. (orig.)

High-Order Curvilinear Finite Element Methods for Lagrangian Hydrodynamics [High Order Curvilinear Finite Elements for Lagrangian Hydrodynamics

Energy Technology Data Exchange (ETDEWEB)

Dobrev, Veselin A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Kolev, Tzanio V. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Rieben, Robert N. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

2012-09-20

The numerical approximation of the Euler equations of gas dynamics in a movingLagrangian frame is at the heart of many multiphysics simulation algorithms. Here, we present a general framework for high-order Lagrangian discretization of these compressible shock hydrodynamics equations using curvilinear finite elements. This method is an extension of the approach outlined in [Dobrev et al., Internat. J. Numer. Methods Fluids, 65 (2010), pp. 1295--1310] and can be formulated for any finite dimensional approximation of the kinematic and thermodynamic fields, including generic finite elements on two- and three-dimensional meshes with triangular, quadrilateral, tetrahedral, or hexahedral zones. We discretize the kinematic variables of position and velocity using a continuous high-order basis function expansion of arbitrary polynomial degree which is obtained via a corresponding high-order parametric mapping from a standard reference element. This enables the use of curvilinear zone geometry, higher-order approximations for fields within a zone, and a pointwise definition of mass conservation which we refer to as strong mass conservation. Moreover, we discretize the internal energy using a piecewise discontinuous high-order basis function expansion which is also of arbitrary polynomial degree. This facilitates multimaterial hydrodynamics by treating material properties, such as equations of state and constitutive models, as piecewise discontinuous functions which vary within a zone. To satisfy the Rankine--Hugoniot jump conditions at a shock boundary and generate the appropriate entropy, we introduce a general tensor artificial viscosity which takes advantage of the high-order kinematic and thermodynamic information available in each zone. Finally, we apply a generic high-order time discretization process to the semidiscrete equations to develop the fully discrete numerical algorithm. Our method can be viewed as the high-order generalization of the so-called staggered

Standard test methods for chemical, mass spectrometric, spectrochemical, nuclear, and radiochemical analysis of nuclear-grade uranyl nitrate solutions

CERN Document Server

American Society for Testing and Materials. Philadelphia

1999-01-01

1.1 These test methods cover procedures for the chemical, mass spectrometric, spectrochemical, nuclear, and radiochemical analysis of nuclear-grade uranyl nitrate solution to determine compliance with specifications. 1.2 The analytical procedures appear in the following order: Sections Determination of Uranium 7 Specific Gravity by Pycnometry 15-20 Free Acid by Oxalate Complexation 21-27 Determination of Thorium 28 Determination of Chromium 29 Determination of Molybdenum 30 Halogens Separation by Steam Distillation 31-35 Fluoride by Specific Ion Electrode 36-42 Halogen Distillate Analysis: Chloride, Bromide, and Iodide by Amperometric Microtitrimetry 43 Determination of Chloride and Bromide 44 Determination of Sulfur by X-Ray Fluorescence 45 Sulfate Sulfur by (Photometric) Turbidimetry 46 Phosphorus by the Molybdenum Blue (Photometric) Method 54-61 Silicon by the Molybdenum Blue (Photometric) Method 62-69 Carbon by Persulfate Oxidation-Acid Titrimetry 70 Conversion to U3O8 71-74 Boron by ...

Some aspects of the quality assurance of personnel carrying out finite element analysis

International Nuclear Information System (INIS)

Dickenson, P.W.

1990-01-01

In this paper, the need to assess the competence of personnel carrying out finite element analysis is emphasised. In carrying out its regulatory role on behalf of the Health and Safety Executive, the Nuclear Installations Inspectorate (NII) must be satisfied that appropriate standards are developed and maintained by the licensee. Since finite element methods have an important bearing on the acceptance of a safety case, it follows that relevant codes should be adequately validated and the personnel applying the code should be competent. Attention is drawn to the work of the Quality Assurance Working Group of the National Agency for Finite Element Methods and Standards (NAFEMS) who are active in this area. The paper also considers the methods that are available to assess the competence of personnel engaged in finite element methods. (author)

Groundwater flow analysis using mixed hybrid finite element method for radioactive waste disposal facilities

International Nuclear Information System (INIS)

Aoki, Hiroomi; Shimomura, Masanori; Kawakami, Hiroto; Suzuki, Shunichi

2011-01-01

In safety assessments of radioactive waste disposal facilities, ground water flow analysis are used for calculating the radionuclide transport pathway and the infiltration flow rate of groundwater into the disposal facilities. For this type of calculations, the mixed hybrid finite element method has been used and discussed about the accuracy of ones in Europe. This paper puts great emphasis on the infiltration flow rate of groundwater into the disposal facilities, and describes the accuracy of results obtained from mixed hybrid finite element method by comparing of local water mass conservation and the reliability of the element breakdown numbers among the mixed hybrid finite element method, finite volume method and nondegenerated finite element method. (author)

Structure-soil-structure interaction of nuclear structures

International Nuclear Information System (INIS)

Snyder, M.D.; Shaw, D.E.; Hall, J.R. Jr.

1975-01-01

Structure-to-structure interaction resulting from coupling of the foundations through the soil has traditionally been neglected in the seismic analysis of nuclear power plants. This paper examines the phenomenon and available methods of analytical treatment, including finite element and lumped parameter methods. Finite element techniques have lead to the treatment of through soil coupling of structural foundations using two dimensional plane strain models owing to the difficulty of considering three dimensional finite element models. The coupling problem is treated by means of a lumped parameter model derived from elastic half-space considerations. Consequently, the method is applicable to the interaction of any number of foundations and allows the simultaneous application of tri-directional excitation. The method entails the idealization of interacting structures as lumped mass/shear beams with lumped soil springs and dampers beneath each foundation plus a coupling matrix between the interacting foundations. Utilizing classical elastic half-space methods, the individual foundation soil springs and dampers may be derived, accounting for the effects of embedment and soil layering, analogous to the methods used for single soil-structure, interaction problems. The coupling matrix is derived by generating influence coefficients based on the geometric relationship of the structures using classical half-space solutions. The influence coefficients form the coupling flexibility matrix which is inverted to yield the coupling matrix for the lumped parameter model

Finite density lattice gauge theories with positive fermion determinants

International Nuclear Information System (INIS)

Sinclair, D.K.; Kogut, J.B.; Toublan, D.

2004-01-01

We perform simulations of (3-colour) QCD with 2 quark flavours at a finite chemical potential μ I for isospin (I 3 ), and of 2-colour QCD at a finite chemical potential μ for quark number. At zero temperature, QCD at finite μ I has a mean-field phase transition at μ I = m π to a superfluid state with a charged pion condensate which spontaneously breaks I 3 . We study the finite temperature transition as a function of μ I . For μ I π , where this is closely related to the transition at finite μ, this appears to be a crossover independent of quark mass, with no sign of the proposed critical endpoint. For μ I > m π this becomes a true phase transition where the pion condensate evaporates. For μ I just above m π the transition seems to be second order, while for larger μ I it appears to become first order. At zero temperature, 2-colour QCD also possesses a superfluid state with a diquark condensate. We study its spectrum of Goldstone and pseudo-Goldstone bosons associated with chiral and quark-number symmetry breaking. (author)

Perturbative study in quantum field theory at finite temperature, application to lepton pair production from a quark-gluon plasma

International Nuclear Information System (INIS)

Altherr, T.

1989-12-01

The main topic of this thesis is a perturbative study of Quantum Field Theory at Finite Temperature. The real-time formalism is used throughout this work. We show the cancellation of infrared and mass singularities in the case of the first order QCD corrections to lepton pair production from a quark-gluon plasma. Two methods of calculation are presented and give the same finite result in the limit of vanishing quark mass. These finite terms are analysed and give small corrections in the region of interest for ultra-relativistic heavy ions collisions, except for a threshold factor. Specific techniques for finite temperature calculations are explicited in the case of the fermionic self-energy in QED [fr

QCD sum rules and applications to nuclear physics

Energy Technology Data Exchange (ETDEWEB)

Cohen, T D [Maryland Univ., College Park, MD (United States). Dept. of Physics; [Washington Univ., Seattle, WA (United States). Dept. of Physics and Inst. for Nuclear Theory; Furnstahl, R J [Ohio State Univ., Columbus, OH (United States). Dept. of Physics; Griegel, D K [Maryland Univ., College Park, MD (United States). Dept. of Physics; [TRIUMF, Vancouver, BC (Canada); Xuemin, J

1994-12-01

Applications of QCD sum-rule methods to the physics of nuclei are reviewed, with an emphasis on calculations of baryon self-energies in infinite nuclear matter. The sum-rule approach relates spectral properties of hadrons propagating in the finite-density medium, such as optical potentials for quasinucleons, to matrix elements of QCD composite operators (condensates). The vacuum formalism for QCD sum rules is generalized to finite density, and the strategy and implementation of the approach is discussed. Predictions for baryon self-energies are compared to those suggested by relativistic nuclear physics phenomenology. Sum rules for vector mesons in dense nuclear matter are also considered. (author). 153 refs., 8 figs.

QCD sum rules and applications to nuclear physics

International Nuclear Information System (INIS)

Cohen, T.D.; Xuemin, J.

1994-12-01

Applications of QCD sum-rule methods to the physics of nuclei are reviewed, with an emphasis on calculations of baryon self-energies in infinite nuclear matter. The sum-rule approach relates spectral properties of hadrons propagating in the finite-density medium, such as optical potentials for quasinucleons, to matrix elements of QCD composite operators (condensates). The vacuum formalism for QCD sum rules is generalized to finite density, and the strategy and implementation of the approach is discussed. Predictions for baryon self-energies are compared to those suggested by relativistic nuclear physics phenomenology. Sum rules for vector mesons in dense nuclear matter are also considered. (author)

Mass in anti-de Sitter spaces

International Nuclear Information System (INIS)

Liu, James T.; Sabra, W.A.

2005-01-01

The boundary stress tensor approach has proven extremely useful in defining mass and angular momentum in asymptotically anti-de Sitter spaces with CFT duals. An integral part of this method is the use of boundary counterterms to regulate the gravitational action and stress tensor. In the presence of matter, however, ambiguities may arise that are related to the addition of possible finite counterterms. We demonstrate this explicitly for R-charged black holes in AdS 5 , where introduction of a finite counterterm proportional to φ 2 is necessary to properly reproduce the expected mass/charge relation for the black holes

Behavior of supersymmetry at finite temperature

International Nuclear Information System (INIS)

Midorikawa, Shoichi.

1984-11-01

Supersymmetry breaking at finite temperature is investigated by using the real-time formalism. We derive the Ward-Takahashi identities of the composite fields by using the path integral formalism. We also calculate the one-loop correction to fermion and boson masses, and discuss the connection of the perturbative result with that obtained from the effective potential. Our result shows that supersymmetry is broken explicitly even in the real-time formalism. (author)

Radiative nonrecoil nuclear finite size corrections of order α(Zα5 to the Lamb shift in light muonic atoms

Directory of Open Access Journals (Sweden)

R.N. Faustov

2017-12-01

Full Text Available On the basis of quasipotential method in quantum electrodynamics we calculate nuclear finite size radiative corrections of order α(Zα5 to the Lamb shift in muonic hydrogen and helium. To construct the interaction potential of particles, which gives the necessary contributions to the energy spectrum, we use the method of projection operators to states with a definite spin. Separate analytic expressions for the contributions of the muon self-energy, the muon vertex operator and the amplitude with spanning photon are obtained. We present also numerical results for these contributions using modern experimental data on the electromagnetic form factors of light nuclei. Keywords: Lamb shift, Muonic atoms, Quantum electrodynamics

Phase transitions in finite systems

Energy Technology Data Exchange (ETDEWEB)

Chomaz, Ph. [Grand Accelerateur National d' Ions Lourds (GANIL), DSM-CEA / IN2P3-CNRS, 14 - Caen (France); Gulminelli, F. [Caen Univ., 14 (France). Lab. de Physique Corpusculaire

2002-07-01

In this series of lectures we will first review the general theory of phase transition in the framework of information theory and briefly address some of the well known mean field solutions of three dimensional problems. The theory of phase transitions in finite systems will then be discussed, with a special emphasis to the conceptual problems linked to a thermodynamical description for small, short-lived, open systems as metal clusters and data samples coming from nuclear collisions. The concept of negative heat capacity developed in the early seventies in the context of self-gravitating systems will be reinterpreted in the general framework of convexity anomalies of thermo-statistical potentials. The connection with the distribution of the order parameter will lead us to a definition of first order phase transitions in finite systems based on topology anomalies of the event distribution in the space of observations. Finally a careful study of the thermodynamical limit will provide a bridge with the standard theory of phase transitions and show that in a wide class of physical situations the different statistical ensembles are irreducibly inequivalent. (authors)

Phase transitions in finite systems

International Nuclear Information System (INIS)

Chomaz, Ph.; Gulminelli, F.

2002-01-01

In this series of lectures we will first review the general theory of phase transition in the framework of information theory and briefly address some of the well known mean field solutions of three dimensional problems. The theory of phase transitions in finite systems will then be discussed, with a special emphasis to the conceptual problems linked to a thermodynamical description for small, short-lived, open systems as metal clusters and data samples coming from nuclear collisions. The concept of negative heat capacity developed in the early seventies in the context of self-gravitating systems will be reinterpreted in the general framework of convexity anomalies of thermo-statistical potentials. The connection with the distribution of the order parameter will lead us to a definition of first order phase transitions in finite systems based on topology anomalies of the event distribution in the space of observations. Finally a careful study of the thermodynamical limit will provide a bridge with the standard theory of phase transitions and show that in a wide class of physical situations the different statistical ensembles are irreducibly inequivalent. (authors)

New developments in the study of the caloric curve for finite nuclei within relativistic models

International Nuclear Information System (INIS)

Menezes, Debora Peres; Providencia, C.

2001-01-01

Relativistic nuclear models have been widely used in describing infinite nuclear matter and finite nuclei properties. With the help of the Thomas Fermi approximation, we have investigated droplet formation in the liquid-gas phase transition in cold and warm asymmetric nuclear matters using the non-linear Walecka model. We have shown that the optimal nuclear size of a droplet in a neutron gas is determined by a delicate balance between nuclear Coulomb and surface energies. On the other hand, the production of several intermediate mass fragments in a short time scale during heavy ion collisions is known as nuclear multifragmentation. In these experiments, the spectator matter has been used to investigate a possible liquid-gas phase transition. The caloric curve, which is given by the excitation energy per nucleon in terms of the thermodynamic temperature is an important quantity to be investigated in the search for a signal of a phase transition. In the present work we obtain the excitation energies of arising droplets in a vapor system, up to T = 6.5 MeV. The droplets are described in terms of a non-linear Walecka-type model with the NL1 parameterization, within the Thomas-Fermi approximation. We conclude that the excitation energies of droplets either corresponding to 150 Sm or 166 Sm, are consistent with the caloric curve in the Fermi gas approximation with a level density parameter A/13. This result agrees with experimental data obtained in heavy-ion collisions at intermediate energies. We have shown that the caloric curve is sensitive to the proton fraction and the inclusion of the Coulomb interaction is important. (author)

Scaling and critical behaviour in nuclear fragmentation

International Nuclear Information System (INIS)

Campi, X.

1990-09-01

These notes review recent results on nuclear fragmentation. An analysis of experimental data from exclusive experiments is made in the framework of modern theories of fragmentation of finite size objects. We discuss the existence of a critical regime of fragmentation and the relevance of scaling and finite size scaling

Application of a general purpose finite element program system in pressure vessel technology

International Nuclear Information System (INIS)

Aamodt, B.; Sandsmark, N.; Medonos, S.

1977-01-01

Main advantages of using general purpose finite element program systems in structural analysis are summarized. Several illustrative applications of the program system SESAM-69 to pressure vessel problems are described. The first example is a dynamic analysis of the motor housing of the internal main circulation pump of a BWR nuclear reactor. The next example is a transient heat conduction and stress analysis of deflector of feeding nozzle of PWR nuclear reactor. Then, numerical calculations of stress intensity factors and fatigue crack growth of semi-elliptical surface cracks are discussed. And finally, an elasto-plastic analysis of a thick plate with edge-cracks is considered. It is concluded that due to the fact that general purpose finite element program systems are general and user-orientated, they will gain increasingly higher popularity in the years ahead

On radii of nuclear potential and density

International Nuclear Information System (INIS)

Bal'butsev, E.B.; Mikhajlov, I.N.

1975-01-01

The Saxon-Woods potential is widely used as an average field in different nuclear models: upsilon(r)=-upsilonsub(0)parameters: upsilonsub(0) is the well depth, Rsub(v) is the well width, a is the diffusivity of the potential edge. The potential parameters should be determined from the data on the nuclear matter distribution. The data available is in agreement with the formula for density: rho(r)=rhosub(0)same sense as Rsub(v), a. The experimental data show that Rsub(v) by 1 Fermi exceed Rsub(rho) approximately. There exist some suggestions that it caused by the finiteness of the radius of action of nuclear forces. It is noted that finiteness of radius of action of forces is a sufficient condition for the presence of this effect. A model is considered in which the matter is limited with a plane surface, so that the density depends only on a single spatial variable normal to the boundary of matter. As is shown by the results, the radius of nuclear potential exceeds that of the volume of the nuclear matter by 0.6 Fermi approximately. The mechanism of this phenomenon takes its origin from a quantum-mechanical effect of turning the wave functions into zero near the infinitely high wall and from their considerable decreasing near the wall of a finite height

Research in theoretical nuclear physics

International Nuclear Information System (INIS)

1993-06-01

The introductory section describes the goals, main thrusts, and interrelationships between the various activities in the program and principal achievements of the Stony Brook Nuclear Theory Group during 1992--93. Details and specific accomplishments are related in abstract form. Current research is taking place in the following areas: strong interaction physics (the physics of hadrons, QCD and the nucleus, QCD at finite temperature and high density), relativistic heavy-ion physics, nuclear structure and nuclear many- body theory, and nuclear astrophysics

Three-dimensional finite element impact analysis of a nuclear waste truck cask

International Nuclear Information System (INIS)

Miller, J.D.

1985-01-01

This paper presents a three-dimensional finite element impact analysis of a hypothetical accident event for the preliminary design of a shipping cask which is used to transport radioactive waste by standard tractor-semitrailer truck. The nonlinear dynamic structural analysis code DYNA3D run on Sandia's Cray-1 computer was used to calculate the effects of the cask's closure-end impacting a rigid frictionless surface on an edge of its external impact limiter after a 30-foot fall. The center of gravity of the cask (made of 304 stainless steel and depleted uranium) was assumed to be directly above the impact point. An elastic-plastic material constitutive model was used to calculate the nonlinear response of the cask components to the transient loading. Interactive color graphics (PATRAN and MOVIE BYU) were used throughout the analysis, proving to be extremely helpful for generation and verification of the geometry and boundary conditions of the finite element model and for interpretation of the analysis results. Results from the calculations show the cask sustained large localized deformations. However, these were almost entirely confined to the impact limiters built into the cask. The closure sections were determined to remain intact, and leakage would not be expected after the event. As an example of a large three-dimensional finite element dynamic impact calculation, this analysis can serve as an excellent benchmark for computer aided design procedures

STAFAN, Fluid Flow, Mechanical Stress in Fractured Rock of Nuclear Waste Repository

International Nuclear Information System (INIS)

Huyakorn, P.; Golis, M.J.

1989-01-01

1 - Description of program or function: STAFAN (Stress And Flow Analysis) is a two-dimensional, finite-element code designed to model fluid flow and the interaction of fluid pressure and mechanical stresses in a fractured rock surrounding a nuclear waste repository. STAFAN considers flow behavior of a deformable fractured system with fracture-porous matrix interactions, the coupling effects of fluid pressure and mechanical stresses in a medium containing discrete joints, and the inelastic response of the individual joints of the rock mass subject to the combined fluid pressure and mechanical loading. 2 - Restrictions on the complexity of the problem: STAFAN does not presently contain thermal coupling, and it is unable to simulate inelastic deformation of the rock mass and variably saturated or two-phase flow in the fractured porous medium system

Scientometric mapping of mass spectrometry research in nuclear science and technology: a global perspective. IT-8

International Nuclear Information System (INIS)

Sagar, Anil; Kademani, B.S.; Vijai Kumar

2007-01-01

This paper attempts to analyse quantitatively the growth and development of Mass Spectrometry research in Nuclear Science and Technology in terms of publication output as reflected in International Nuclear Information System (INIS) database (1970-2005). During 1970-2005, a total of 10913 papers were published in various domains: Chemistry, Materials and Earth Sciences (5286) (48.44%), Physical Sciences (2367) (21.69%), Engineering and Technology (1434) (13.14), Life and Environmental Sciences (1212) (11.11), other aspects of Nuclear and Non Nuclear Energy (492) (4.51%) and Isotopes, Isotope and Radiation Applications (122) (1.12%). There were only three papers published in 1970. The highest number of papers (816) were published in 2004. The average number of publications published per year was 303.13. United States topped the list with 2247 publications followed by Germany with 1333 publications, Japan with 820 publications, France with 525 publications, and India with 460 publications. Authorship and collaboration trend was towards multi-authored papers as 81.83 percent of the papers were collaborative is indicative of the multidisciplinary nature of research activity. The most prolific authors were: S.K. Aggarwal, Bhabha Atomic Research Centre, Mumbai, India with 113 publications, W. Kutschera, University of Vienna, Austria with 85 publications, and H.C. Jain, Bhabha Atomic Research Centre, Mumbai, India with 70 publications. The highly productive institutions were: Bhabha Atomic Research Centre, Mumbai (India) with 233 publications, Argonne National Laboratory (USA) with 150 publications, Oak Ridge National Laboratory (USA) with 146 publications, University of California (USA) with 118 publications, Los Alamos National Laboratory (USA) with 104 publications and Japan Atomic Energy Research Institute (Japan) with 91 publications. The journals most preferred by the scientists for publication of papers were: Nuclear Instruments and Methods in Physics Research

Advertising campaigns on the necessity of nuclear energy through mass-media in Japan

International Nuclear Information System (INIS)

Niwano, Sadaji

1998-01-01

provide the public with materials and elements to think and decide with as information. In the background of those circumstances, the attitudes of PA activities toward the public-has changed recently to draw public attention to the wide range of issues from current severe energy conditions in Japan to global environmental problems connecting to the role and the position of nuclear power among overall national energy policies in Japan and let have urgent feelings among the public. Followings are the examples that we are taking up in promotion of advertising campaigns through mass media, including inter- net and other information tools. (1) To show concrete measures to be taken to meet national long- term energy supply/demand outlook for the year to 2030 that encourage energy- saving efforts, increased use of new energy sources and further development of nuclear power generation. (2) In this December, the 3rd Conference of the Parties to United Nations Framework Convention on Climate Change will be held at Kyoto, Japan. At this very moment that national attentions are increasingly concentrating toward the energy and environment issues, we will intend to hold advertising campaigns widely through mass media to heighten public awareness on the necessity of nuclear power promotion, as well as conservation and energy efficiency measures, introduction of alternative energy sources, such as solar, wind etc. in connection with the necessity of tackling the environmental problems, especially global warming phenomenon due to the greenhouse gas emissions. At this occasion, taking up some topics of specifically rapid energy demand which will obviously continue well into the next century and will very likely cause impending energy situations in Asian countries, expectations of serious environmental problems particularly in those of Asian countries, and among that appealing the role of nuclear energy as a clean energy source

The 1992 FRDM mass model and unstable nuclei

International Nuclear Information System (INIS)

Moeller, P.

1994-01-01

We discuss the reliability of a recent global nuclear-structure calculation in regions far from β stability. We focus on the results for nuclear masses, but also mention other results obtained in the nuclear-structure calculation, for example ground-state spins. We discuss what should be some minimal requirements of a nuclear mass model and study how the macroscopic-microscopic method and other nuclear mass models fullfil such basic requirements. We study in particular the reliability of nuclear mass models in regions of nuclei that were not considered in the determination of the model parameters

Fragmentation of giant dipole resonance at finite temperature

International Nuclear Information System (INIS)

Vdovin, A.

2005-01-01

It is well known that the main part of a width of a collective giant resonance built on the ground state in heavy nuclei is due to coupling of one-phonon vibrational states with more complex ones like two phonon or two-particle - two-hole. So it seems natural that the same idea was also explored in studying of the formation and dependence on temperature of a width of giant resonances built on a compound nuclear state. The first microscopic calculations of a giant dipole resonance width at finite temperature have demonstrated its weak dependence on T whereas the experimental width Γ exp strongly increases up to T≤3 MeV. The observed thermal behaviour of Γ exp was attributed mainly to thermal fluctuations of a nuclear shape at finite T . However, further theoretical studies of the problem have shown a strengthening of the GDR spreading with T. We calculate a fragmentation of the giant dipole resonance in hot spherical nuclei within the approach based on the quasiparticle-phonon model extended to finite temperature in with the formalism of thermofield dynamics. The fragmentation of collective giant dipole vibrations at finite T is due to the coupling with 'two-thermal phonon' configurations. The energies and structures of thermal phonon states are calculated from the thermal RPA temperature dependence of the variance σ th of a theoretical E1 strength function and the experimental GDR width Γ exp in 120 Sn. The coupling of thermal phonons is determined by their fermionic structure. The variance σ th of the E1 strength function is found continuously increasing with temperature. The main reason of this behavior is the coupling of the dipole phonons with very low-lying particle-particle (hole-hole) thermal phonons. These phonons are noncollective ones and they appear only at T≠0. The calculated T dependence of σ th is quite similar to that of the experimental width Γ exp in 120 Sn and 208 Pb

Heavy ion collisions with A = 1057: Aspects of nuclear stability and the nuclear equation of state in coalescing neutron-star binary systems

International Nuclear Information System (INIS)

Mathews, G.J.; Wilson, J.R.; Evans, C.R.; Detweiler, S.L.

1987-12-01

The dynamics of the final stages of the coalescence of two neturon stars (such as the binary pulsar PSR 1913+16) is an unsolved problem in astrophysics. Such systems are probably efficient generators of gravitational radiation, and may be significant contributors to heavy-element nucleosynthesis. The input physics for the study of such systems is similar to that required for the strudy of heavy-ion collision hydrodynamics; e.g., a finite temperature nuclear equation of state, properties of nuclei away from stability, etc. We discuss the development of a relativistic hydrodynamics code in three spatial dimensions for the purpose of studying such neutron-star systems. The properties of the mass-radius relation (determined by the nuclear equation of state) may lead to a proposed mechanism by which hot, highly neutronized matter is ejected from the coalescing stars. This material is photodisintegrated into a free (mostly) neutron gas which may subsequently experience rapid-neutron capture (r-process) nucleosynthesis. 15 refs., 4 figs

Expected brine movement at potential nuclear waste repository salt sites

International Nuclear Information System (INIS)

McCauley, V.S.; Raines, G.E.

1987-08-01

The BRINEMIG brine migration code predicts rates and quantities of brine migration to a waste package emplaced in a high-level nuclear waste repository in salt. The BRINEMIG code is an explicit time-marching finite-difference code that solves a mass balance equation and uses the Jenks equation to predict velocities of brine migration. Predictions were made for the seven potentially acceptable salt sites under consideration as locations for the first US high-level nuclear waste repository. Predicted total quantities of accumulated brine were on the order of 1 m 3 brine per waste package or less. Less brine accumulation is expected at domal salt sites because of the lower initial moisture contents relative to bedded salt sites. Less total accumulation of brine is predicted for spent fuel than for commercial high-level waste because of the lower temperatures generated by spent fuel. 11 refs., 36 figs., 29 tabs

Level-density parameter of nuclei at finite temperature

International Nuclear Information System (INIS)

Gregoire, C.; Kuo, T.T.S.; Stout, D.B.

1991-01-01

The contribution of particle-particle (hole-hole) and of particle-hole ring diagrams to the nuclear level-density parameter at finite temperature is calculated. We first derive the correlated grand potential with the above ring diagrams included to all orders by way of a finite temperature RPA equation. An expression for the correlated level-density parameter is then obtained by differentiating the grand potential. Results obtained for the 40 Ca nucleus with realistic matrix elements derived from the Paris potential are presented. The contribution of the RPA correlations is found to be important, being significantly larger than typical Hartree-Fock results. The temperature dependence of the level-density parameter derived in the present work is generally similar to that obtained in a schematic model. Comparison with available experimental data is discussed. (orig.)

Mass hierarchy and energy scaling of the Tsallis - Pareto parameters in hadron productions at RHIC and LHC energies

Science.gov (United States)

Bíró, Gábor; Barnaföldi, Gergely Gábor; Biró, Tamás Sándor; Shen, Keming

2018-02-01

The latest, high-accuracy identified hadron spectra measurements in highenergy nuclear collisions led us to the investigation of the strongly interacting particles and collective effects in small systems. Since microscopical processes result in a statistical Tsallis - Pareto distribution, the fit parameters q and T are well suited for identifying system size scalings and initial conditions. Moreover, parameter values provide information on the deviation from the extensive, Boltzmann - Gibbs statistics in finite-volumes. We apply here the fit procedure developed in our earlier study for proton-proton collisions [1, 2]. The observed mass and center-of-mass energy trends in the hadron production are compared to RHIC dAu and LHC pPb data in different centrality/multiplicity classes. Here we present new results on mass hierarchy in pp and pA from light to heavy hadrons.

Chiral and continuum extrapolation of partially-quenched hadron masses

International Nuclear Information System (INIS)

Chris Allton; Wes Armour; Derek Leinweber; Anthony Thomas; Ross Young

2005-01-01

Using the finite-range regularization (FRR) of chiral effective field theory, the chiral extrapolation formula for the vector meson mass is derived for the case of partially-quenched QCD. We re-analyze the dynamical fermion QCD data for the vector meson mass from the CP-PACS collaboration. A global fit, including finite lattice spacing effects, of all 16 of their ensembles is performed. We study the FRR method together with a naive polynomial approach and find excellent agreement (∼1%) with the experimental value of M ρ from the former approach. These results are extended to the case of the nucleon mass

Chiral and continuum extrapolation of partially-quenched hadron masses

Energy Technology Data Exchange (ETDEWEB)

Chris Allton; Wes Armour; Derek Leinweber; Anthony Thomas; Ross Young

2005-09-29

Using the finite-range regularization (FRR) of chiral effective field theory, the chiral extrapolation formula for the vector meson mass is derived for the case of partially-quenched QCD. We re-analyze the dynamical fermion QCD data for the vector meson mass from the CP-PACS collaboration. A global fit, including finite lattice spacing effects, of all 16 of their ensembles is performed. We study the FRR method together with a naive polynomial approach and find excellent agreement ({approx}1%) with the experimental value of M{sub {rho}} from the former approach. These results are extended to the case of the nucleon mass.

Supersymmetric QED at finite temperature and the principle of equivalence

International Nuclear Information System (INIS)

Robinett, R.W.

1985-01-01

Unbroken supersymmetric QED is examined at finite temperature and it is shown that the scalar and spinor members of a chiral superfield acquire different temperature-dependent inertial masses. By considering the renormalization of the energy-momentum tensor it is also shown that the T-dependent scalar-spinor gravitational masses are also no longer degenerate and, moreover, are different from their T-dependent inertial mass shifts implying a violation of the equivalence principle. The temperature-dependent corrections to the spinor (g-2) are also calculated and found not to vanish

Accelerator-based ultrasensitive mass spectrometry

International Nuclear Information System (INIS)

Gove, H.E.

1985-01-01

This chapter describes a new mass spectrometry technique involving charged particle accelerators normally used for basic research in nuclear science. Topics considered include the limitations of conventional mass spectrometry, the limitations of the direct measurement of radioactive decay, mass spectrometry using a tandem electrostatic accelerator, mass spectrometry using a cyclotron, how accelerator mass spectrometry circumvents the limitations of conventional mass spectrometry, measurements of stable isotopes, nuclear physics and astrophysics applications, modifications to existing accelerators, descriptions of dedicated systems, and future applications

Large geometry secondary ion mass spectrometry (LG-SIMS) for the enhancement of nuclear safeguards applications

International Nuclear Information System (INIS)

Helberg, P.M.L.; Wallenius, M.; Vincent, C.; Albert, N.; Peres, P.; Truyens, J.

2013-01-01

A new LG-SIMS (Large Geometry Secondary Ion Mass Spectrometry) laboratory is currently being established at the Joint Research Centre, the Institute of Transuranium Elements for the purpose of improving the analytical capabilities within the European Commission. The laboratory will mainly be used for analysing uranium bearing aerosol particles collected on cotton swipes from nuclear Safeguards inspections but it will also be used for Nuclear Forensics and other Safeguards related applications. Until recently, this type of analysis has predominantly been performed using the small geometry CAMECA IMS 3F-7F instrument series. These instruments provide both particle screening and isotope ratio capabilities. The performance of these instruments was however limited by the occurrence of isobaric interferences, in particular for the minor isotopes ( 234 U, 236 U), that could not be resolved without compromising the transmission of the instrument. A recent breakthrough to solve this problem has been the implementation of Large Geometry SIMS, the CAMECA 1270 / 1280 / 1280-HR models, for this type of analysis. This instrument has originally been developed for geosciences applications requiring both high transmission and high mass resolution capabilities. This came out to be a key instrumental advantage also for uranium particle analyses, as it allows efficient removal of common molecular interferences with minimum loss in transmission. Furthermore an electrostatic ion optical device has been added for increasing the mass dispersion which allows the simultaneous detection of all uranium isotopes. The Automated Particle Measurement (APM) software has been developed to perform screening measurement in an automated mode. Combined with the APM screening software, LG-SIMS instruments greatly improve the overall performance and throughput of isotopic analyses of U particles for nuclear Safeguards purposes. The paper is followed by the slides of the presentation. (A.C.)

Finite-width effects in unstable-particle production at hadron colliders

Energy Technology Data Exchange (ETDEWEB)

Falgari, P. [Utrecht Univ. (Netherlands). Inst. for Theoretical Physics; Utrecht Univ. (Netherlands). Spinoza Inst.; Papanastasiou, A.S. [Deutsches Elektronen-Synchrotron DESY, Hamburg (Germany); Signer, A. [Paul Scherrer Institut, Villigen (Switzerland); Zuerich Univ. (Switzerland). Inst. for Theoretical Physics

2013-03-15

We present a general formalism for the calculation of finite-width contributions to the differential production cross sections of unstable particles at hadron colliders. In this formalism, which employs an effective-theory description of unstable-particle production and decay, the matrix element computation is organized as a gauge-invariant expansion in powers of {Gamma}{sub X}/m{sub X}, with {Gamma}{sub X} and m{sub X} the width and mass of the unstable particle. This framework allows for a systematic inclusion of off-shell and non-factorizable effects whilst at the same time keeping the computational effort minimal compared to a full calculation in the complex-mass scheme. As a proof-of-concept example, we give results for an NLO calculation of top-antitop production in the q anti q partonic channel. As already found in a similar calculation of single-top production, the finite-width effects are small for the total cross section, as expected from the naive counting {proportional_to}{Gamma}{sub t}/m{sub t}{proportional_to}1%. However, they can be sizeable, in excess of 10%, close to edges of certain kinematical distributions. The dependence of the results on the mass renormalization scheme, and its implication for a precise extraction of the top-quark mass, is also discussed.

Finite-width effects in unstable-particle production at hadron colliders

International Nuclear Information System (INIS)

Falgari, P.; Signer, A.; Zuerich Univ.

2013-03-01

We present a general formalism for the calculation of finite-width contributions to the differential production cross sections of unstable particles at hadron colliders. In this formalism, which employs an effective-theory description of unstable-particle production and decay, the matrix element computation is organized as a gauge-invariant expansion in powers of Γ X /m X , with Γ X and m X the width and mass of the unstable particle. This framework allows for a systematic inclusion of off-shell and non-factorizable effects whilst at the same time keeping the computational effort minimal compared to a full calculation in the complex-mass scheme. As a proof-of-concept example, we give results for an NLO calculation of top-antitop production in the q anti q partonic channel. As already found in a similar calculation of single-top production, the finite-width effects are small for the total cross section, as expected from the naive counting ∝Γ t /m t ∝1%. However, they can be sizeable, in excess of 10%, close to edges of certain kinematical distributions. The dependence of the results on the mass renormalization scheme, and its implication for a precise extraction of the top-quark mass, is also discussed.

Update on nuclear structure effects in light muonic atoms

Energy Technology Data Exchange (ETDEWEB)

Hernandez, Oscar Javier, E-mail: javierh@triumf.ca; Dinur, Nir Nevo; Ji, Chen; Bacca, Sonia [TRIUMF (Canada); Barnea, Nir [The Hebrew University, Racah Institute of Physics (Israel)

2016-12-15

We present calculations of the nuclear structure corrections to the Lamb shift in light muonic atoms, using state-of-the-art nuclear potentials. We outline updated results on finite nucleon size contributions.

Exact vacuum polarization in 1 + 1 dimensional finite nuclei

International Nuclear Information System (INIS)

Ferree, T.C.

1992-01-01

There is considerable interest in the use of renormalizable quantum field theories to describe nuclear structure. In particular, theories which employ hadronic degrees of freedom are used widely and lead to efficient models which allow self-consistent solutions of the many-body problem. An interesting feature inherent to relativistic field theories (like QHD) is the presence of an infinite sea of negative energy fermion (nucleon) states, which interact dynamically with positive energy fermions via other fields. Such interactions give rise to, for example, vacuum polarization effects, in which virtual particle-antiparticle pairs interact with positive energy valence nucleons as well as with each other, and can significantly influence the ground and excited states of nuclear systems. Several authors have addressed this question in various approximations for finite nuclei, mostly based on extensions of results derived for a uniform system of nucleons. Some attempts have also been made to include vacuum effects in finite systems exactly, but the presence of a vector potential can be problematic when working in a spectral representation. In this paper, the author presents a computational method by which vacuum polarization effects in finite nuclei can be calculated exactly in the RHA by employing matrix diagonalization methods in a discrete Fourier representation of the Dirac equation, and an approximate method for including deep negative energy states based on a derivative expansion of the effective action. This efficient approach is shown to provide well-behaved vacuum polarization densities which remain so even in the presence of strong vector potential

Activities report in nuclear physics

NARCIS (Netherlands)

Jansen, J. F. W.; Scholten, O.

1987-01-01

Experimental studies of giant resonances, nuclear structure, light mass systems, and heavy mass systems are summarized. Theoretical studies of nuclear structure, and dynamics are described. Electroweak interactions; atomic and surface physics; applied nuclear physics; and nuclear medicine are

A Kohn–Sham equation solver based on hexahedral finite elements

International Nuclear Information System (INIS)

Fang Jun; Gao Xingyu; Zhou Aihui

2012-01-01

We design a Kohn–Sham equation solver based on hexahedral finite element discretizations. The solver integrates three schemes proposed in this paper. The first scheme arranges one a priori locally-refined hexahedral mesh with appropriate multiresolution. The second one is a modified mass-lumping procedure which accelerates the diagonalization in the self-consistent field iteration. The third one is a finite element recovery method which enhances the eigenpair approximations with small extra work. We carry out numerical tests on each scheme to investigate the validity and efficiency, and then apply them to calculate the ground state total energies of nanosystems C 60 , C 120 , and C 275 H 172 . It is shown that our solver appears to be computationally attractive for finite element applications in electronic structure study.

Comparative aseismic response study of different analytical models of nuclear power plant

International Nuclear Information System (INIS)

Takemori, T.; Ogiwara, Y.; Kawakatsu, T.; Abe, Y.; Kitade, K.

1977-01-01

This study consists of two major sections; one is comparison of magnification factor of input acceleration between finite model and spring-mass model, the other is evaluation of modified spring-mass models for aseismic design of nuclear power plant. The structure model used in this study is a P.W.R. reactor containment building composed of the outer shield wall, the steel containment and the internal structure. The rigidity of the foundation rock is represented by shear wave velocity Vs. The magnification of bedrock acceleration at the structure foundation, main floors and free surface of foundation rock are calculated using axisymmetric finite element analytical model with various rock rigidities. The outer shield wall and the steel containment are represented by shell elements, and the internal structure and foundation rock are represented by quadrilateral elements. Each nodal point has four degrees of freedom, in shell element, and three in quadrilateral element. The total degrees of this analytical model are large, so the eigenvalue is calculated by the subspace iterative method. The responses are calculated by time history of acceleration and response spectrum based on the mode superposition method. The spring-mass model is most used in aseismic design for its simplicity. But, if the foundation rock spring is calculated assuming the semi-infinite elastic solid, the analyses of the magnification of acceleration in foundation rock are limited. From the calculated results of the F.E.M. model, the modification of the spring-mass model is estimated, considering the magnification ratio of foundation rock beneath the structure

Assessment for hydrodynamic masses of HANARO flow tubes

International Nuclear Information System (INIS)

Ryu, Jeong Soo; Cho, Yeong Garp; Kim, Doo Kie; Woo, Jong Sug; Park, Jin Ho

2000-06-01

The effect of hydrodynamic masses is investigated in dynamic characteristics and seismic response analyses of the submerged HANARO hexagonal flow tubes. Consistent hydrodynamic masses of the surrounding water are evaluated by the prepared program using the finite element method, in which arbitrary cross-sections of submerged structures and boundary conditions of the surrounding fluid can be considered. Also lumped hydrodynamic masses are calculated using simple formula applied to hexagonal flow tubes in the infinite fluid. Modal analyses and seismic response spectrum analyses were performed using hydrodynamic masses obtained by the finite element method and the simple formula. The results of modal analysis were verified by comparing the results measured from modal tests. And the displacement results of the seismic response spectrum analysis were assessed by comparing the consistent and the lumped hydrodynamic masses obtained by various methods. Finally practical criteria based on parametric studies are proposed as the lumped hydrodynamic masses for HANARO flow tubes

Assessment for hydrodynamic masses of HANARO flow tubes

Energy Technology Data Exchange (ETDEWEB)

Ryu, Jeong Soo; Cho, Yeong Garp; Kim, Doo Kie; Woo, Jong Sug; Park, Jin Ho

2000-06-01

The effect of hydrodynamic masses is investigated in dynamic characteristics and seismic response analyses of the submerged HANARO hexagonal flow tubes. Consistent hydrodynamic masses of the surrounding water are evaluated by the prepared program using the finite element method, in which arbitrary cross-sections of submerged structures and boundary conditions of the surrounding fluid can be considered. Also lumped hydrodynamic masses are calculated using simple formula applied to hexagonal flow tubes in the infinite fluid. Modal analyses and seismic response spectrum analyses were performed using hydrodynamic masses obtained by the finite element method and the simple formula. The results of modal analysis were verified by comparing the results measured from modal tests. And the displacement results of the seismic response spectrum analysis were assessed by comparing the consistent and the lumped hydrodynamic masses obtained by various methods. Finally practical criteria based on parametric studies are proposed as the lumped hydrodynamic masses for HANARO flow tubes.

Shell structure and orbit bifurcations in finite fermion systems

Science.gov (United States)

Magner, A. G.; Yatsyshyn, I. S.; Arita, K.; Brack, M.

2011-10-01

We first give an overview of the shell-correction method which was developed by V.M. Strutinsky as a practicable and efficient approximation to the general self-consistent theory of finite fermion systems suggested by A.B. Migdal and collaborators. Then we present in more detail a semiclassical theory of shell effects, also developed by Strutinsky following original ideas of M.C. Gutzwiller. We emphasize, in particular, the influence of orbit bifurcations on shell structure. We first give a short overview of semiclassical trace formulae, which connect the shell oscillations of a quantum system with a sum over periodic orbits of the corresponding classical system, in what is usually called the "periodic orbit theory". We then present a case study in which the gross features of a typical double-humped nuclear fission barrier, including the effects of mass asymmetry, can be obtained in terms of the shortest periodic orbits of a cavity model with realistic deformations relevant for nuclear fission. Next we investigate shell structures in a spheroidal cavity model which is integrable and allows for far-going analytical computation. We show, in particular, how period-doubling bifurcations are closely connected to the existence of the so-called "superdeformed" energy minimum which corresponds to the fission isomer of actinide nuclei. Finally, we present a general class of radial power-law potentials which approximate well the shape of a Woods-Saxon potential in the bound region, give analytical trace formulae for it and discuss various limits (including the harmonic oscillator and the spherical box potentials).

Lagrangian and Eulerian finite element techniques for transient fluid-structure interaction problems

International Nuclear Information System (INIS)

Donea, J.; Fasoli-Stella, P.; Giuliani, S.

1977-01-01

The basic finite element equations for transient compressible fluid flow are presented in a form that allows the elements to be moved with the fluid in normal Lagrangian fashion, to be held fixed in a Eulerian manner, or to be moved in some arbitrarily specified way. The co-existence of Lagrangian and Eulerian regions within the finite element mesh will permit to handle greater distortions in the fluid motion than would be allowed by a purely Lagrangian method, with more resolution than is afforded by a purely Eulerian method. To achieve a mixed formulation, the conservation statements of mass, momentum and energy are expressed in integral form over a reference volume whose surface may be moving with an arbitrarily prescribed velocity. Direct use can be made of the integral forms of the mass and energy equations to adjust the element density and specific internal energy. The Galerkin process is employed to formulate a variational statement associated with the momentum equation. The difficulties associated with the presence of convective terms in the conservation equations are handled by expressing transports of mass, momentum and energy terms of intermediate velocities derived at each cycle from the previous cycle velocities and accelerations. The hydrodynamic elements presented are triangles, quadrilaterals with constant pressure and density. The finite element equations associated with these elements are described in the necessary detail. Numerical results are presented based on purely Lagrangian, purely Eulerian and mixed formulations. Simple problems with analytic solution are solved first to show the validity and accuracy of the proposed mixed finite element formulation. Then, practical problems are illustrated in the field of fast reactor safety analysis

Finite volume for three-flavour Partially Quenched Chiral Perturbation Theory through NNLO in the meson sector

Science.gov (United States)

Bijnens, Johan; Rössler, Thomas

2015-11-01

We present a calculation of the finite volume corrections to meson masses and decay constants in three flavour Partially Quenched Chiral Perturbation Theory (PQChPT) through two-loop order in the chiral expansion for the flavour-charged (or off-diagonal) pseudoscalar mesons. The analytical results are obtained for three sea quark flavours with one, two or three different masses. We reproduce the known infinite volume results and the finite volume results in the unquenched case. The calculation has been performed using the supersymmetric formulation of PQChPT as well as with a quark flow technique.

Evaluation of the pressure loads generated by hydrogen explosion in auxiliary nuclear building

International Nuclear Information System (INIS)

Ahmed Bentaib; Alexandre Bleyer; Pierre Pailhories; Jean-Pierre L'heriteau; Bernard Chaumont; Jerome Dupas; Jerome Riviere

2005-01-01

Full text of publication follows: In the framework of nuclear safety, a hydrogen leaks in the auxiliary nuclear building would raise a explosion hazard. A local ignition of the combustible mixture would give birth initially to a slow flame, rapidly accelerated by obstacles. This flame acceleration is responsible for high pressure loads that can damage the auxiliary building and destroy safety equipments in it. In this paper, we evaluate the pressure loads generated by an hydrogen explosion for both bounding and realistic explosion scenarios. The bounding scenarios use stoichiometric hydrogen-air mixtures and the realistic scenarios correspond to hydrogen leaks with mass flow rate varying between 1 g/s and 9 g/s. For every scenario, the impact of the ignition location and ignition time are investigated. The hydrogen dispersion and explosion are computed using the TONUS code. The dispersion model used is based on a finite element solver and the explosion is simulated by a structured finite volumes EULER equation solver and the combustion model CREBCOM which simulates the hydrogen/air turbulent flame propagation, taking into account 3D complex geometry and reactants concentration gradients. The pressure loads computed are then used to investigate the occurrence of a mechanical failure of the tanks located in the auxiliary nuclear building and containing radioactive fluids. The EUROPLEXUS code is used to perform 3D mechanical calculations because the loads are non uniform and of rather short deviation. (authors)

Azimuthally anisotropic hydride lens structures in Zircaloy 4 nuclear fuel cladding: High-resolution neutron radiography imaging and BISON finite element analysis

Science.gov (United States)

Lin, Jun-Li; Zhong, Weicheng; Bilheux, Hassina Z.; Heuser, Brent J.

2017-12-01

High-resolution neutron radiography has been used to image bulk circumferential hydride lens particles in unirradiated Zircaloy 4 tubing cross section specimens. Zircaloy 4 is a common light water nuclear reactor (LWR) fuel cladding; hydrogen pickup, hydride formation, and the concomitant effect on the mechanical response are important for LWR applications. Ring cross section specimens with three hydrogen concentrations (460, 950, and 2830 parts per million by weight) and an as-received reference specimen were imaged. Azimuthally anisotropic hydride lens particles were observed at 950 and 2830 wppm. The BISON finite element analysis nuclear fuel performance code was used to model the system elastic response induced by hydride volumetric dilatation. The compressive hoop stress within the lens structure becomes azimuthally anisotropic at high hydrogen concentrations or high hydride phase fraction. This compressive stress anisotropy matches the observed lens anisotropy, implicating the effect of stress on hydride formation as the cause of the observed lens azimuthal asymmetry. The cause and effect relation between compressive stress and hydride lens anisotropy represents an indirect validation of a key BISON output, the evolved hoop stress associated with hydride formation.

Advances in dynamic relaxation techniques for nonlinear finite element analysis

International Nuclear Information System (INIS)

Sauve, R.G.; Metzger, D.R.

1995-01-01

Traditionally, the finite element technique has been applied to static and steady-state problems using implicit methods. When nonlinearities exist, equilibrium iterations must be performed using Newton-Raphson or quasi-Newton techniques at each load level. In the presence of complex geometry, nonlinear material behavior, and large relative sliding of material interfaces, solutions using implicit methods often become intractable. A dynamic relaxation algorithm is developed for inclusion in finite element codes. The explicit nature of the method avoids large computer memory requirements and makes possible the solution of large-scale problems. The method described approaches the steady-state solution with no overshoot, a problem which has plagued researchers in the past. The method is included in a general nonlinear finite element code. A description of the method along with a number of new applications involving geometric and material nonlinearities are presented. They include: (1) nonlinear geometric cantilever plate; (2) moment-loaded nonlinear beam; and (3) creep of nuclear fuel channel assemblies

Finite field-energy of a point charge in QED

International Nuclear Information System (INIS)

Costa, Caio V; Gitman, Dmitry M; Shabad, Anatoly E

2015-01-01

We consider a simple nonlinear (quartic in the fields) gauge-invariant modification of classical electrodynamics, to show that it possesses a regularizing ability sufficient to make the field energy of a point charge finite. The model is exactly solved in the class of static central-symmetric electric fields. Collation with quantum electrodynamics (QED) results in the total field energy of a point elementary charge about twice the electron mass. The proof of the finiteness of the field energy is extended to include any polynomial selfinteraction, thereby the one that stems from the truncated expansion of the Euler–Heisenberg local Lagrangian in QED in powers of the field strength. (paper)

A finite element simulation on transient large deformation and mass diffusion in electrodes for lithium ion batteries

International Nuclear Information System (INIS)

An, Yonghao; Jiang, Hanqing

2013-01-01

Lithium-ion batteries have attracted great deal of attention recently. Silicon is one of the most promising anode materials for high-performance lithium-ion batteries, due to its highest theoretical specific capacity. However, the short lifetime confined by mechanical failure in the silicon anode is now considered to be the biggest challenge in desired applications. High stress induced by the huge volume change due to lithium insertion/extraction is the main reason underlying this problem. Some theoretical models have been developed to address this issue. In order to properly implement these models, we develop a finite element based numerical method using a commercial software package, ABAQUS, as a platform at the continuum level to study fully coupled large deformation and mass diffusion problem. Using this method, large deformation, elasticity–plasticity of the electrodes, various spatial and temporal conditions, arbitrary geometry and dimension could be fulfilled. The interaction between anode and other components of the lithium ion batteries can also be studied as an integrated system. Several specific examples are presented to demonstrate the capability of this numerical platform. (paper)

New trends in nuclear collective dynamics

International Nuclear Information System (INIS)

Abe, Yasuhisa; Horiuchi, Hisashi; Matsuyanagi, Kenichi

1992-01-01

New Trends in Nuclear Collective Dynamics comprises reviews by well-known researchers from international centers of nuclear physics. This overview of recent advances concentrates on - order amd chaos in finite quantum systems - dissipation in heavy-ion collions - collective motion in warm nuclei - time-dependent mean-field theory with collision terms - nuclear fission and multi-dimensional tunneling - large scale collective motion see hints under the relevent topics. (orig.) With 90 figs

A finite range coupled channel Born approximation code

International Nuclear Information System (INIS)

Nagel, P.; Koshel, R.D.

1978-01-01

The computer code OUKID calculates differential cross sections for direct transfer nuclear reactions in which multistep processes, arising from strongly coupled inelastic states in both the target and residual nuclei, are possible. The code is designed for heavy ion reactions where full finite range and recoil effects are important. Distorted wave functions for the elastic and inelastic scattering are calculated by solving sets of coupled differential equations using a Matrix Numerov integration procedure. These wave functions are then expanded into bases of spherical Bessel functions by the plane-wave expansion method. This approach allows the six-dimensional integrals for the transition amplitude to be reduced to products of two one-dimensional integrals. Thus, the inelastic scattering is treated in a coupled channel formalism while the transfer process is treated in a finite range born approximation formalism. (Auth.)

Infrared divergences, mass shell singularities and gauge dependence of the dynamical fermion mass

International Nuclear Information System (INIS)

Das, Ashok K.; Frenkel, J.; Schubert, C.

2013-01-01

We study the behavior of the dynamical fermion mass when infrared divergences and mass shell singularities are present in a gauge theory. In particular, in the massive Schwinger model in covariant gauges we find that the pole of the fermion propagator is divergent and gauge dependent at one loop, but the leading singularities cancel in the quenched rainbow approximation. On the other hand, in physical gauges, we find that the dynamical fermion mass is finite and gauge independent at least up to one loop

A fully coupled finite element framework for thermal fracturing simulation in subsurface cold CO2 injection

Directory of Open Access Journals (Sweden)

Shunde Yin

2018-03-01

Simulation of thermal fracturing during cold CO2 injection involves the coupled processes of heat transfer, mass transport, rock deforming as well as fracture propagation. To model such a complex coupled system, a fully coupled finite element framework for thermal fracturing simulation is presented. This framework is based on the theory of non-isothermal multiphase flow in fracturing porous media. It takes advantage of recent advances in stabilized finite element and extended finite element methods. The stabilized finite element method overcomes the numerical instability encountered when the traditional finite element method is used to solve the convection dominated heat transfer equation, while the extended finite element method overcomes the limitation with traditional finite element method that a model has to be remeshed when a fracture is initiated or propagating and fracturing paths have to be aligned with element boundaries.

Research in theoretical nuclear physics

International Nuclear Information System (INIS)

1990-06-01

We shall organize the description of our many activities under following broad headings: Strong Interaction Physics: the physics of hadrons; QCD and the nucleus; and QCD at finite temperature and high density. Relativistic Heavy Ion Physics. Nuclear Structure and Many-body Theory. Nuclear Astrophysics. While these are the main areas of activity of the Stony Brood group, they do not cover all activities

Simulations of cold nuclear matter at sub-saturation densities

Energy Technology Data Exchange (ETDEWEB)

Giménez Molinelli, P.A., E-mail: pagm@df.uba.ar [Departamento de Física, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires and IFIBA, CONICET, Ciudad Universitaria, Buenos Aires 1428 (Argentina); Nichols, J.I. [Departamento de Física, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires and IFIBA, CONICET, Ciudad Universitaria, Buenos Aires 1428 (Argentina); López, J.A. [Department of Physics, University of Texas at El Paso, El Paso, TX 79968 (United States); Dorso, C.O. [Departamento de Física, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires and IFIBA, CONICET, Ciudad Universitaria, Buenos Aires 1428 (Argentina)

2014-03-01

Ideal nuclear matter is expected to undergo a first order phase transition at the thermodynamic limit. At such phase transitions the size of density fluctuations (bubbles or droplets) scale with the size of the system. This means that simulations of nuclear matter at sub-saturation densities will inexorably suffer from what is vaguely referred to as “finite size effects”. It is usually thought that these finite size effects can be diminished by imposing periodic boundary conditions and making the system large enough, but as we show in this work, that is actually not the case at sub-saturation densities. In this paper we analyze the equilibrium configurations of molecular dynamics simulations of a classical model for symmetric ideal (uncharged) nuclear matter at sub-saturation densities and low temperatures, where phase coexistence is expected at the thermodynamic limit. We show that the most stable configurations in this density range are almost completely determined by artificial aspects of the simulations (i.e. boundary conditions) and can be predicted analytically by surface minimization. This result is very general and is shown to hold true for several well known semi-classical models of nuclear interaction and even for a simple Lennard-Jones potential. Also, in the limit of very large systems, when “small size” effects can be neglected, those equilibrium configurations seem to be restricted to a few structures reminiscent to the “Pasta Phases” expected in Neutron Star matter, but arising from a completely different origin: In Neutron Star matter, the non-homogeneous structures arise from a competition between nuclear and Coulomb interactions while for ideal nuclear matter they emerge from finite (yet not “small”) size effects. The role of periodic boundary conditions and finite size effects in Neutron Star matter simulations are reexamined.

Finite element modelling

International Nuclear Information System (INIS)

Tonks, M.R.; Williamson, R.; Masson, R.

2015-01-01

The Finite Element Method (FEM) is a numerical technique for finding approximate solutions to boundary value problems. While FEM is commonly used to solve solid mechanics equations, it can be applied to a large range of BVPs from many different fields. FEM has been used for reactor fuels modelling for many years. It is most often used for fuel performance modelling at the pellet and pin scale, however, it has also been used to investigate properties of the fuel material, such as thermal conductivity and fission gas release. Recently, the United Stated Department Nuclear Energy Advanced Modelling and Simulation Program has begun using FEM as the basis of the MOOSE-BISON-MARMOT Project that is developing a multi-dimensional, multi-physics fuel performance capability that is massively parallel and will use multi-scale material models to provide a truly predictive modelling capability. (authors)

Structural analysis and incipient failure detection of primary circuit components based on correlation-analysis and finite-element models

International Nuclear Information System (INIS)

Olma, B.J.

1977-01-01

A method is presented to compute vibrational power spectral densities (VPSD's) of primary circuit components based on a finite-element representation of the primary circuit. First this method has been applied to the sodium cooled reactor KNK, Karlsruhe. Now a further application is being developed for a BWR-nuclear power plant. The experimentally determined VPSD's can be considered as the output of a multiple input-output system. They have to be explained as the frequency response of a multidimensional mechanical system, which is excited by stochastic and deterministic mechanical driving forces. The stochastic mechanical forces are generated by the dynamic pressure fluctuations of the fluid. The deterministic mechanical forces are caused by the pressure fluctuations, which are induced by the main coolant pumps or by standing waves. The excitation matrix can be obtained from measured pressure fluctuations. The vibration transfer function matrix can be computed from the mass matrix, damping matrix and stiffness matrix of a theoretical finite-element model or mass-spring model. Based on this theory the computer code 'STAMPO' has been established. This program has been applied to the KNK reactor. The excitation matrix was created from measured jet-noise pressure fluctuations. The mass-, stiffness- and damping matrix has been extracted from a SAP-IV-model of the primary system. Sequentially for each frequency point the complete VPSD matrix has been computed. The diagonal elements of this matrix represent the vibrational auto-power spectral densities, the off-diagonal elements represent the vibrational cross-power spectral densities. The calculations give good agreement with measured VPSD's. The comparison shows that the measured jet-noise pressure fluctuations act nearly uncorrelated on the structure, whereas the output VPSD's are well correlated

Nuclear collective flow from gaussian fits to triple differential distributions

International Nuclear Information System (INIS)

Gosset, J.; Babinet, R.; Cavata, C.; Marco, M. de; Demoulins, M.; Fanet, H.; Fodor, Z.; L'Hote, D.; Lucas, B.

1990-01-01

A simple characterization of triple differential cross sections is needed for a systematic study of the nuclear matter collective flow in relativistic nucleus-nucleus collisions. Our analysis is based upon a fitting procedure, so that the triple differential distributions need not be measured in the whole momentum space. If the detector acceptance eliminates most spectator particles or if it is artificially restricted for doing so, this method leads to a flow characterization of the participant nuclear matter. The center-of-mass triple-differential momentum distributions are fitted to a simple analytical shape, namely an anisotropic Gaussian distribution. The adjusted parameters (flow angle and aspect ratios) are corrected for uncertainty in the event-by-event determination of the reaction plane azimuth (finite-number effects). Results are presented for neon-nucleus and argon-nucleus collisions at incident energy between 400 and 800 MeV per nucleon. Flow is already significant for light systems, and depends clearly upon the impact parameter

Theoretical studies in nuclear reactions and nuclear structure

International Nuclear Information System (INIS)

1992-05-01

Research in the Maryland Nuclear Theory Group focusses on problems in four basic areas of current relevance. Hadrons in nuclear matter; the structure of hadrons; relativistic nuclear physics and heavy ion dynamics and related processes. The section on hadrons in nuclear matter groups together research items which are aimed at exploring ways in which the properties of nucleons and the mesons which play a role in the nuclear force are modified in the nuclear medium. A very interesting result has been the finding that QCD sum rules supply a new insight into the decrease of the nucleon's mass in the nuclear medium. The quark condensate, which characterizes spontaneous chiral symmetry breaking of the late QCD vacuum, decreases in nuclear matter and this is responsible for the decrease of the nucleon's mass. The section on the structure of hadrons contains progress reports on our research aimed at understanding the structure of the nucleon. Widely different approaches are being studied, e.g., lattice gauge calculations, QCD sum rules, quark-meson models with confinement and other hedgehog models. A major goal of this type of research is to develop appropriate links between nuclear physics and QCD. The section on relativistic nuclear physics represents our continuing interest in developing an appropriate relativistic framework for nuclear dynamics. A Lorentz-invariant description of the nuclear force suggests a similar decrease of the nucleon's mass in the nuclear medium as has been found from QCD sum rules. Work in progress extends previous successes in elastic scattering to inelastic scattering of protons by nuclei. The section on heavy ion dynamics and related processes reports on research into the e + e - problem and heavy ion dynamics

Decay of a hot zone in finite nuclei

International Nuclear Information System (INIS)

De, J.N.; Gregoire, C.

1987-01-01

Assuming that a hot zone is formed in nuclear collisions, we study its decay in the surrounding colder nuclear matter. Thermal equilibration resulting from energy transport is analyzed in terms of a classical model and within the Vlasov-Uehling-Uhlenbeck self-consistent approach. Convection is found to be the dominant energy propagation mode. Thermal equilibration time is found to be of the order of the damping of isoscalar quadrupole vibration, i.e. a few 10 -21 sec. This feature may not be fully consistent with recent available experimental data and casts doubt on the possibility of formation of a sharply localised thermally equilibrated hot zone as a likely intermediate state for excitation in finite nuclei in intermediate energy collisions. 16 refs

Halo-independent direct detection analyses without mass assumptions

International Nuclear Information System (INIS)

Anderson, Adam J.; Fox, Patrick J.; Kahn, Yonatan; McCullough, Matthew

2015-01-01

Results from direct detection experiments are typically interpreted by employing an assumption about the dark matter velocity distribution, with results presented in the m χ −σ n plane. Recently methods which are independent of the DM halo velocity distribution have been developed which present results in the v min −g-tilde plane, but these in turn require an assumption on the dark matter mass. Here we present an extension of these halo-independent methods for dark matter direct detection which does not require a fiducial choice of the dark matter mass. With a change of variables from v min to nuclear recoil momentum (p R ), the full halo-independent content of an experimental result for any dark matter mass can be condensed into a single plot as a function of a new halo integral variable, which we call h-til-tilde(p R ). The entire family of conventional halo-independent g-tilde(v min ) plots for all DM masses are directly found from the single h-tilde(p R ) plot through a simple rescaling of axes. By considering results in h-tilde(p R ) space, one can determine if two experiments are inconsistent for all masses and all physically possible halos, or for what range of dark matter masses the results are inconsistent for all halos, without the necessity of multiple g-tilde(v min ) plots for different DM masses. We conduct a sample analysis comparing the CDMS II Si events to the null results from LUX, XENON10, and SuperCDMS using our method and discuss how the results can be strengthened by imposing the physically reasonable requirement of a finite halo escape velocity

From anomalies of finite symmetries to heterotic GUTs

Science.gov (United States)

Vaudrevange, Patrick K. S.

2017-11-01

We review the role of finite symmetries for particle physics with special emphasis on discrete anomalies and on their possible origin from extra dimensions. Then, we apply our knowledge on finite symmetries to the problematic proton decay operators of various mass-dimensions, focusing on ℤ4R , i.e. a special R-symmetry of order 4. We show that this ℤ4R symmetry can naturally originate from extra dimensions as a discrete remnant of higher-dimensional Lorentz symmetry. Finally, in order to obtain a unified picture from the heterotic string theory we discuss grand unified theories (GUTs) in extra dimensions compactified on ℤ2 × ℤ2 orbifolds and show how proton decay operators can be suppressed in a certain class of orbifolds.

Finite element model for nonlinear shells of revolution

International Nuclear Information System (INIS)

Cook, W.A.

1979-01-01

Nuclear material shipping containers have shells of revolution as basic structural components. Analytically modeling the response of these containers to severe accident impact conditions requires a nonlinear shell-of-revolution model that accounts for both geometric and material nonlinearities. Existing models are limited to large displacements, small rotations, and nonlinear materials. The paper presents a finite element model for a nonlinear shell of revolution that will account for large displacements, large strains, large rotations, and nonlinear materials

TITUS: a general finite element system

International Nuclear Information System (INIS)

Bougrelle, P.

1983-01-01

TITUS is a general finite element structural analysis system which performs linear/non-linear, static/dynamic analyses of heat-transfer/thermo-mechanical problems. One of the major features of TITUS is that it was designed by engineers, to address engineers in an industrial environment. This has resulted in an easy to use system, with a high-level free-formatted problem oriented language, a large selection of pre- and post processors and sophisticated graphic capabilities. TITUS has many references in civil, mechanical and nuclear engineering applications. The TITUS system is available on various types of machines, from large mainframes to mini computers

Nuclear matter in all its states

International Nuclear Information System (INIS)

Bonche, P.; Cugnon, J.; Babinet, R.; Mathiot, J.F.; Van Hove, L.; Buenerd, M.; Galin, J.; Lemaire, M.C.; Meyer, J.

1986-01-01

This report includes the nine lectures which have been presented at the Joliot-Curie School of Nuclear Physics in 1985. The subjects covered are the following: thermodynamic description of excited nuclei; heavy ion reactions at high energy (theoretical approach); heavy ion reactions at high energy (experimental approach); relativistic nuclear physics and quark effects in nuclei; quark matter; nuclear compressibility and its experimental determinations; hot nuclei; anti p-nucleus interaction; geant resonances at finite temperature [fr

Coulomb breakup of 31Ne using finite range DWBA

International Nuclear Information System (INIS)

Shubhchintak; Chatterjee, R.

2013-01-01

Coulomb breakup of nuclei away from the valley of stability have been one of the most successful probes to unravel their structure. However, it is only recently that one is venturing into medium mass nuclei like 23 O and 31 Ne. This is a very new and exciting development which has expanded the field of light exotic nuclei to the deformed medium mass region. In this contribution, an extension of the previously proposed theory of Coulomb breakup within the post-form finite range distorted wave Born approximation to include deformation of the projectile is reported

A Simple Correlation for Neutron Capture Rates from Nuclear Masses

Energy Technology Data Exchange (ETDEWEB)

Couture, Aaron Joseph [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2018-01-30

Recent studies of neutron capture performed at LANL have revealed a previously unrecognized connection between nuclear masses and the average neutron capture cross section. A team of three scientists from Los Alamos (P-27), Yale Univ., and Istanbul Univ. (Turkey) recently discovered this connection and have published their results as a Rapid Communication in Physical Review C. Neutron capture is a reaction in which a free neutron is absorbed by the nucleus, keeping the element unchanged, but changing isotopes. This reaction is typically exothermic. As a result, the reaction can proceed even when many other reaction channels are closed. In an astrophysical environment, this means that neutron capture is the primary mechanism by which all of the elements with atomic number greater than nickel are produced is neutron capture.

fB from finite size effects in lattice QCD

International Nuclear Information System (INIS)

Guagnelli, M.; Palombi, F.; Petronzio, R.; Tantalo, N.

2003-01-01

We discuss a novel method to calculate f B on the lattice, introduced in [1], based on the study of the dependence of finite size effects upon the heavy quark mass of flavoured mesons and on a non-perturbative recursive finite size technique. This method avoids the systematic errors related to extrapolations from the static limit or to the tuning of the coefficients of effective Lagrangian and the results admit an extrapolation to the continuum limit. We show the results of a first estimate at finite lattice spacing, but close to the continuum limit, giving f B = 170(11)(5)(22) MeV. We also obtain f B s = 192(9)(5)(24)MeV. The first error is statistical, the second is our estimate of the systematic error from the method and the third the systematic error from the specific approximations adopted in this first exploratory calculation. The method can be generalized to two-scale problems in lattice QCD

Semiclassical description of hot nuclear systems

International Nuclear Information System (INIS)

Brack, M.

1984-01-01

We present semiclassical density variational calculations for highly excited nuclear systems. We employ the newly derived functionals tau[rho] and sigma[rho] of the extended Thomas-Fermi (ETF) model, generalized to finite temperatures. Excellent agreement is reached with Hartree-Fock (HF) results. We also calculated the fission barrier of 240 Pu as a function of the nuclear temperature

Neutrino mass matrices with vanishing determinant

International Nuclear Information System (INIS)

Chauhan, Bhag C.; Pulido, Joao; Picariello, Marco

2006-01-01

We investigate the prospects for neutrinoless double beta decay, texture zeros. and equalities between neutrino mass matrix elements in scenarios with vanishing determinant mass matrices for vanishing and finite θ 13 mixing angles in normal and inverse mass hierarchies. For normal hierarchy and both zero and finite θ 13 it is found that neutrinoless double beta decay cannot be observed by any of the present or next generation experiments, while for inverse hierarchy it is, on the contrary, accessible to experiments. Regarding texture zeros and equalities between mass matrix elements, we find that in both normal and inverse hierarchies with θ 13 =0 no texture zeros nor any such equalities can exist apart from the obvious ones. For θ 13 ≠0 some texture zeros become possible. In normal hierarchy two texture zeros occur if 8.1x10 -2 ≤sinθ 13 ≤9.1x10 -2 while in inverse hierarchy three are possible, one with sinθ 13 ≥7x10 -3 and two others with sinθ 13 ≥0.18. All equalities between mass matrix elements are impossible with θ 13 ≠0

Mass media communication of emergency issues and countermeasures in a nuclear accident: Fukushima reporting in European newspapers

International Nuclear Information System (INIS)

Gallego, Eduardo; Cantone, Marie Claire; Oughton, Deborah H.; Tomkiv, Yevgeniya; Perko, Tanja; Prezelj, Iztok

2017-01-01

This paper presents the results of a large study of 1340 articles published by two major newspapers in six European countries (Belgium, Italy, Norway, Slovenia, Spain and Russia) in the first 2 months after the Fukushima Daiichi nuclear disaster. The focus of the analysis is on the application and overall impact of protective actions, both during the emergency phase and later, how the newspapers describe those actions, which differences were apparent between countries and what recommendations can be extracted in order to improve general communication about these issues. A clear lesson is that, even under uncertainty and recognising limitations, responsible authorities need to provide transparent, clear and understandable information to the public and the mass media right from the beginning of the early phase of any nuclear emergency. Clear, concise messages should be given. Mass media could play a key role in reassuring the public if the countermeasures are clearly explained. (authors)

The magnetic centrifugal mass filter

International Nuclear Information System (INIS)

Fetterman, Abraham J.; Fisch, Nathaniel J.

2011-01-01

Mass filters using rotating plasmas have been considered for separating nuclear waste and spent nuclear fuel. We propose a new mass filter that utilizes centrifugal and magnetic confinement of ions in a way similar to the asymmetric centrifugal trap. This magnetic centrifugal mass filter is shown to be more proliferation resistant than present technology. This filter is collisional and produces well confined output streams, among other advantages.

The magnetic centrifugal mass filter

Energy Technology Data Exchange (ETDEWEB)

Fetterman, Abraham J.; Fisch, Nathaniel J. [Department of Astrophysical Sciences, Princeton University, Princeton, New Jersey 08540 (United States)

2011-09-15

Mass filters using rotating plasmas have been considered for separating nuclear waste and spent nuclear fuel. We propose a new mass filter that utilizes centrifugal and magnetic confinement of ions in a way similar to the asymmetric centrifugal trap. This magnetic centrifugal mass filter is shown to be more proliferation resistant than present technology. This filter is collisional and produces well confined output streams, among other advantages.

Finite element analysis of ageing reinforced and prestressed concrete structures in nuclear plant - An international review of current capabilities and priorities for future developments

International Nuclear Information System (INIS)

2002-01-01

Nuclear plants contain a variety of concrete structures whose structural performance is essential to the safety of the plant. There is a requirement to demonstrate the robustness of these structures during normal operating and extreme accident conditions, throughout their life. During this time, the concrete may degrade due to the effects of ageing. This degradation must be accounted for during the assessment of their performance. Finite Element Analysis (FEA) techniques have tremendous potential for providing valuable insight into the behaviour of these aged concrete structures under a range of different loading conditions. Advanced FEA techniques currently enjoy widespread use within the nuclear industry for the non-linear analysis of concrete. Many practitioners within the nuclear industry are at the forefront of the industrial application of these methods. However, in some areas, the programs that are commercially available lag behind the best information available from research. This document is an international review of current capabilities and priorities for future development relating to non-linear finite element analysis of reinforced and prestressed concrete in the nuclear industry in the various member states. Particular attention is paid to the analysis of degraded or ageing structures. This report: 1. Summarises the needs for FEA of aged concrete nuclear structures; 2. Details the existing capabilities, not just in terms of what the software is capable of, but also in terms of the current practices employed by those in industry; 3. Looks at how engineers, within the nuclear industry, working in this field would like to see methods improved, and identifies the factors that are limiting current practice; 4. Summarises ongoing research that may provide beneficial technological advances; 5. Assigns priorities to the different development requests; 6. Selects those developments that are felt to be of greatest benefit to industry and provides a qualitative

Theoretical studies in nuclear reactions and nuclear structure

Energy Technology Data Exchange (ETDEWEB)

1992-05-01

Research in the Maryland Nuclear Theory Group focusses on problems in four basic areas of current relevance. Hadrons in nuclear matter; the structure of hadrons; relativistic nuclear physics and heavy ion dynamics and related processes. The section on hadrons in nuclear matter groups together research items which are aimed at exploring ways in which the properties of nucleons and the mesons which play a role in the nuclear force are modified in the nuclear medium. A very interesting result has been the finding that QCD sum rules supply a new insight into the decrease of the nucleon's mass in the nuclear medium. The quark condensate, which characterizes spontaneous chiral symmetry breaking of the late QCD vacuum, decreases in nuclear matter and this is responsible for the decrease of the nucleon's mass. The section on the structure of hadrons contains progress reports on our research aimed at understanding the structure of the nucleon. Widely different approaches are being studied, e.g., lattice gauge calculations, QCD sum rules, quark-meson models with confinement and other hedgehog models. A major goal of this type of research is to develop appropriate links between nuclear physics and QCD. The section on relativistic nuclear physics represents our continuing interest in developing an appropriate relativistic framework for nuclear dynamics. A Lorentz-invariant description of the nuclear force suggests a similar decrease of the nucleon's mass in the nuclear medium as has been found from QCD sum rules. Work in progress extends previous successes in elastic scattering to inelastic scattering of protons by nuclei. The section on heavy ion dynamics and related processes reports on research into the e{sup +}e{sup {minus}} problem and heavy ion dynamics.

Deconstructing scalar QED at zero and finite temperature

International Nuclear Information System (INIS)

Kan, N.; Sakamoto, K.; Shiraishi, K.

2003-01-01

We calculate the effective potential for the WLPNGB in a world with a circular latticized extra dimension. The mass of the Wilson line pseudo-Nambu-Goldstone boson (WLPNGB) is calculated from the one-loop quantum effect of scalar fields at zero and finite temperature. We show that a series expansion by the modified Bessel functions is useful to calculate the one-loop effective potentials. (orig.)

Non-perturbative quark mass renormalization

CERN Document Server

Capitani, S.; Luescher, M.; Sint, S.; Sommer, R.; Weisz, P.; Wittig, H.

1998-01-01

We show that the renormalization factor relating the renormalization group invariant quark masses to the bare quark masses computed in lattice QCD can be determined non-perturbatively. The calculation is based on an extension of a finite-size technique previously employed to compute the running coupling in quenched QCD. As a by-product we obtain the $\\Lambda$--parameter in this theory with completely controlled errors.