Expansions of Fermi and symmetrized Fermi integrals and applications in nuclear physics

International Nuclear Information System (INIS)

Grypeos, M.; Koutroulos, C.; Luk'yanov, V.; Shebeko, A.

1998-01-01

A detailed study is undertaken, using various techniques, in deriving expansions of integrals containing the Fermi or the symmetrized Fermi distributions. The results are presented in a mathematically compact form and consist of generalizations and extensions of previously known expansions. The relevance of the results to quantities of interest in nuclear physics is recalled and particular attention is paid to the so-called exponentially small terms which may play an essential role in certain cases

Pion Condensation and Alternating Layer Spin Model in Symmetric Nuclear Matter : Use of Extended Effective Nuclear Forces : Nuclear Physics

OpenAIRE

Teiji, KUNIHIRO; Tatsuyuki, TAKATSUKA; Ryozo, TAMAGAKI; Department of National Sciences, Ryukoku University; College of Humanities and Social Sciences, Iwate University; Department of Physics, Kyoto University

1985-01-01

Pion condensation in the symmetric nuclear matter is investigated on the basis of the ALS (alternating-layer-spin) model which provides a good description for the π^0 condensation. We perform energy calculations in a realistic way where the isobar (Δ)-mixing, the short range effects and the exchange energy of the interaction are taken into account. The Δ-mixing effect is built in the model state as previously done in the neutron matter. We preferentially employ G-0 force of Sprung and Banerje...

EXCEPTIONAL POINTS IN OPEN AND PT-SYMMETRIC SYSTEMS

Directory of Open Access Journals (Sweden)

Hichem Eleuch

2014-04-01

Full Text Available Exceptional points (EPs determine the dynamics of open quantum systems and cause also PT symmetry breaking in PT symmetric systems. From a mathematical point of view, this is caused by the fact that the phases of the wavefunctions (eigenfunctions of a non-Hermitian Hamiltonian relative to one another are not rigid when an EP is approached. The system is therefore able to align with the environment to which it is coupled and, consequently, rigorous changes of the system properties may occur. We compare analytically as well as numerically the eigenvalues and eigenfunctions of a 2 × 2 matrix that is characteristic either of open quantum systems at high level density or of PT symmetric optical lattices. In both cases, the results show clearly the influence of the environment on the system in the neighborhood of EPs. Although the systems are very different from one another, the eigenvalues and eigenfunctions indicate the same characteristic features.

Parametric amplification and bidirectional invisibility in PT -symmetric time-Floquet systems

Science.gov (United States)

Koutserimpas, Theodoros T.; Alù, Andrea; Fleury, Romain

2018-01-01

Parity-time (PT )-symmetric wave devices, which exploit balanced interactions between material gain and loss, exhibit extraordinary properties, including lasing and flux-conserving scattering processes. In a seemingly different research field, periodically driven systems, also known as time-Floquet systems, have been widely studied as a relevant platform for reconfigurable active wave control and manipulation. In this article, we explore the connection between PT -symmetry and parametric time-Floquet systems. Instead of relying on material gain, we use parametric amplification by considering a time-periodic modulation of the refractive index at a frequency equal to twice the incident signal frequency. We show that the scattering from a simple parametric slab, whose dynamics follows the Mathieu equation, can be described by a PT -symmetric scattering matrix, whose PT -breaking threshold corresponds to the Mathieu instability threshold. By combining different parametric slabs modulated out of phase, we create PT -symmetric time-Floquet systems that feature exceptional scattering properties, such as coherent perfect absorption (CPA)-laser operation and bidirectional invisibility. These bidirectional properties, rare for regular PT -symmetric systems, are related to a compensation of parametric amplification due to multiple scattering between two parametric systems modulated with a phase difference.

Quantum work relations and response theory in parity-time-symmetric quantum systems

Science.gov (United States)

Wei, Bo-Bo

2018-01-01

In this work, we show that a universal quantum work relation for a quantum system driven arbitrarily far from equilibrium extends to a parity-time- (PT -) symmetric quantum system with unbroken PT symmetry, which is a consequence of microscopic reversibility. The quantum Jarzynski equality, linear response theory, and Onsager reciprocal relations for the PT -symmetric quantum system are recovered as special cases of the universal quantum work relation in a PT -symmetric quantum system. In the regime of broken PT symmetry, the universal quantum work relation does not hold because the norm is not preserved during the dynamics.

Solution of generalized shifted linear systems with complex symmetric matrices

International Nuclear Information System (INIS)

Sogabe, Tomohiro; Hoshi, Takeo; Zhang, Shao-Liang; Fujiwara, Takeo

2012-01-01

We develop the shifted COCG method [R. Takayama, T. Hoshi, T. Sogabe, S.-L. Zhang, T. Fujiwara, Linear algebraic calculation of Green’s function for large-scale electronic structure theory, Phys. Rev. B 73 (165108) (2006) 1–9] and the shifted WQMR method [T. Sogabe, T. Hoshi, S.-L. Zhang, T. Fujiwara, On a weighted quasi-residual minimization strategy of the QMR method for solving complex symmetric shifted linear systems, Electron. Trans. Numer. Anal. 31 (2008) 126–140] for solving generalized shifted linear systems with complex symmetric matrices that arise from the electronic structure theory. The complex symmetric Lanczos process with a suitable bilinear form plays an important role in the development of the methods. The numerical examples indicate that the methods are highly attractive when the inner linear systems can efficiently be solved.

Non-Abelian behavior of α bosons in cold symmetric nuclear matter

International Nuclear Information System (INIS)

Zheng Hua; Bonasera, Aldo

2011-01-01

The ground-state energy of infinite symmetric nuclear matter is usually described by strongly interacting nucleons obeying the Pauli exclusion principle. We can imagine a unitary transformation which groups four nonidentical nucleons (i.e., with different spin and isospin) close in coordinate space. Those nucleons, being nonidentical, do not obey the Pauli principle, thus their relative momenta are negligibly small (just to fulfill the Heisenberg principle). Such a cluster can be identified with an α boson. But in dense nuclear matter, those α particles still obey the Pauli principle since are constituted of fermions. The ground state energy of nuclear matter α clusters is the same as for nucleons, thus it is degenerate. We could think of α particles as vortices which can now braid, for instance making 8 Be which leave the ground state energy unchanged. Further braiding to heavier clusters ( 12 C, 16 O,...) could give a different representation of the ground state at no energy cost. In contrast d-like clusters (i.e., N=Z odd-odd nuclei, where N and Z are the neutron and proton number, respectively) cannot describe the ground state of nuclear matter and can be formed at high excitation energies (or temperatures) only. We show that even-even, N=Z, clusters could be classified as non-Abelian states of matter. As a consequence an α condensate in nuclear matter might be hindered by the Fermi motion, while it could be possible a condensate of 8 Be or heavier clusters.

Influence of flow constraints on the properties of the critical endpoint of symmetric nuclear matter

Science.gov (United States)

Ivanytskyi, A. I.; Bugaev, K. A.; Sagun, V. V.; Bravina, L. V.; Zabrodin, E. E.

2018-06-01

We propose a novel family of equations of state for symmetric nuclear matter based on the induced surface tension concept for the hard-core repulsion. It is shown that having only four adjustable parameters the suggested equations of state can, simultaneously, reproduce not only the main properties of the nuclear matter ground state, but the proton flow constraint up its maximal particle number densities. Varying the model parameters we carefully examine the range of values of incompressibility constant of normal nuclear matter and its critical temperature, which are consistent with the proton flow constraint. This analysis allows us to show that the physically most justified value of nuclear matter critical temperature is 15.5-18 MeV, the incompressibility constant is 270-315 MeV and the hard-core radius of nucleons is less than 0.4 fm.

Color symmetrical superconductivity in a schematic nuclear quark model

DEFF Research Database (Denmark)

Bohr, Henrik; Providencia, C.; da Providencia, J.

2010-01-01

In this letter, a novel BCS-type formalism is constructed in the framework of a schematic QCD inspired quark model, having in mind the description of color symmetrical superconducting states. In the usual approach to color superconductivity, the pairing correlations affect only the quasi-particle...... states of two colors, the single-particle states of the third color remaining unaffected by the pairing correlations. In the theory of color symmetrical superconductivity here proposed, the pairing correlations affect symmetrically the quasi-particle states of the three colors and vanishing net color...

Pseudo-Hermitian description of PT-symmetric systems defined on a complex contour

International Nuclear Information System (INIS)

Mostafazadeh, Ali

2005-01-01

We describe a method that allows for a practical application of the theory of pseudo-Hermitian operators to PT-symmetric systems defined on a complex contour. We apply this method to study the Hamiltonians H = p 2 + x 2 (ix) ν with ν ε (-2, ∞) that are defined along the corresponding anti-Stokes lines. In particular, we reveal the intrinsic non-Hermiticity of H for the cases that ν is an even integer, so that H p 2 ± x 2+ν , and give a proof of the discreteness of the spectrum of H for all ν ε (-2, ∞). Furthermore, we study the consequences of defining a square-well Hamiltonian on a wedge-shaped complex contour. This yields a PT-symmetric system with a finite number of real eigenvalues. We present a comprehensive analysis of this system within the framework of pseudo-Hermitian quantum mechanics. We also outline a direct pseudo-Hermitian treatment of PT-symmetric systems defined on a complex contour which clarifies the underlying mathematical structure of the formulation of PT-symmetric quantum mechanics based on the charge-conjugation operator. Our results provide conclusive evidence that pseudo-Hermitian quantum mechanics provides a complete description of general PT-symmetric systems regardless of whether they are defined along the real line or a complex contour

Information Retrieval and Criticality in Parity-Time-Symmetric Systems.

Science.gov (United States)

Kawabata, Kohei; Ashida, Yuto; Ueda, Masahito

2017-11-10

By investigating information flow between a general parity-time (PT-)symmetric non-Hermitian system and an environment, we find that the complete information retrieval from the environment can be achieved in the PT-unbroken phase, whereas no information can be retrieved in the PT-broken phase. The PT-transition point thus marks the reversible-irreversible criticality of information flow, around which many physical quantities such as the recurrence time and the distinguishability between quantum states exhibit power-law behavior. Moreover, by embedding a PT-symmetric system into a larger Hilbert space so that the entire system obeys unitary dynamics, we reveal that behind the information retrieval lies a hidden entangled partner protected by PT symmetry. Possible experimental situations are also discussed.

Facade Layout Symmetrization

KAUST Repository

Jiang, Haiyong

2016-04-11

We present an automatic algorithm for symmetrizing facade layouts. Our method symmetrizes a given facade layout while minimally modifying the original layout. Based on the principles of symmetry in urban design, we formulate the problem of facade layout symmetrization as an optimization problem. Our system further enhances the regularity of the final layout by redistributing and aligning boxes in the layout. We demonstrate that the proposed solution can generate symmetric facade layouts efficiently. © 2015 IEEE.

Facade Layout Symmetrization

KAUST Repository

Jiang, Haiyong; Dong, Weiming; Yan, Dongming; Zhang, Xiaopeng

2016-01-01

We present an automatic algorithm for symmetrizing facade layouts. Our method symmetrizes a given facade layout while minimally modifying the original layout. Based on the principles of symmetry in urban design, we formulate the problem of facade layout symmetrization as an optimization problem. Our system further enhances the regularity of the final layout by redistributing and aligning boxes in the layout. We demonstrate that the proposed solution can generate symmetric facade layouts efficiently. © 2015 IEEE.

Conjugate gradient type methods for linear systems with complex symmetric coefficient matrices

Science.gov (United States)

Freund, Roland

1989-01-01

We consider conjugate gradient type methods for the solution of large sparse linear system Ax equals b with complex symmetric coefficient matrices A equals A(T). Such linear systems arise in important applications, such as the numerical solution of the complex Helmholtz equation. Furthermore, most complex non-Hermitian linear systems which occur in practice are actually complex symmetric. We investigate conjugate gradient type iterations which are based on a variant of the nonsymmetric Lanczos algorithm for complex symmetric matrices. We propose a new approach with iterates defined by a quasi-minimal residual property. The resulting algorithm presents several advantages over the standard biconjugate gradient method. We also include some remarks on the obvious approach to general complex linear systems by solving equivalent real linear systems for the real and imaginary parts of x. Finally, numerical experiments for linear systems arising from the complex Helmholtz equation are reported.

Symmetric and Programmable Multi-Chip Module for Low-Power Prototyping System

OpenAIRE

Yen, Mao-Hsu; Chen, Sao-Jie; Lan, Sanko H.

2001-01-01

The advantages of a Multi-Chip Module (MCM) product are its low-power and small-size. But the design of an MCM system usually requires weeks of engineering effort, thus we need a generic MCM substrate with programmable interconnections to accelerate system prototyping. In this paper, we propose a Symmetric and Programmable MCM (SPMCM) substrate for this purpose. This SPMCM substrate consists of a symmetrical array of slots for bare-chip attachment and Field Programmable Interco...

Spontaneous symmetry breaking in ΡΤ symmetric systems with nonlinear damping

International Nuclear Information System (INIS)

Karthiga, S.; Chandrasekar, V.K.; Senthilvelan, M.; Lakshmanan, M.

2016-01-01

In this talk, we discuss the remarkable role of position dependent damping in determining the parametric regions of symmetry breaking in nonlinear ΡΤ -symmetric systems. We illustrate the nature of ΡΤ-symmetry preservation and breaking with reference to a remarkable integrable scalar nonlinear system. In the two dimensional cases of such position dependent damped systems, we unveil the existence of a class of novel bi-ΡΤ -symmetric systems which have two fold ΡΤ symmetries. We discuss the dynamics of these systems and show how symmetry breaking occurs, that is whether the symmetry breaking of the two ΡΤ symmetries occurs in pair or occurs one by one. The addition of linear damping in these nonlinearly damped systems induces competition between the two types of damping. This competition results in a ΡΤ phase transition in which the ΡΤ symmetry is broken for lower loss/gain strength and is restored by increasing the loss/gain strength. We also show that by properly designing the form of the position dependent damping, we can tailor the ΡΤ-symmetric regions of the system. (author)

Systems of Differential Equations with Skew-Symmetric, Orthogonal Matrices

Science.gov (United States)

Glaister, P.

2008-01-01

The solution of a system of linear, inhomogeneous differential equations is discussed. The particular class considered is where the coefficient matrix is skew-symmetric and orthogonal, and where the forcing terms are sinusoidal. More general matrices are also considered.

An iteration for indefinite and non-symmetric systems and its application to the Navier-Stokes equations

Energy Technology Data Exchange (ETDEWEB)

Wathen, A. [Oxford Univ. (United Kingdom); Golub, G. [Stanford Univ., CA (United States)

1996-12-31

A simple fixed point linearisation of the Navier-Stokes equations leads to the Oseen problem which after appropriate discretisation yields large sparse linear systems with coefficient matrices of the form (A B{sup T} B -C). Here A is non-symmetric but its symmetric part is positive definite, and C is symmetric and positive semi-definite. Such systems arise in other situations. In this talk we will describe and present some analysis for an iteration based on an indefinite and symmetric preconditioner of the form (D B{sup T} B -C).

Symmetric extendibility of quantum states

OpenAIRE

Nowakowski, Marcin L.

2015-01-01

Studies on symmetric extendibility of quantum states become especially important in a context of analysis of one-way quantum measures of entanglement, distilabillity and security of quantum protocols. In this paper we analyse composite systems containing a symmetric extendible part with a particular attention devoted to one-way security of such systems. Further, we introduce a new one-way monotone based on the best symmetric approximation of quantum state. We underpin those results with geome...

Norm estimates of complex symmetric operators applied to quantum systems

International Nuclear Information System (INIS)

Prodan, Emil; Garcia, Stephan R; Putinar, Mihai

2006-01-01

This paper communicates recent results in the theory of complex symmetric operators and shows, through two non-trivial examples, their potential usefulness in the study of Schroedinger operators. In particular, we propose a formula for computing the norm of a compact complex symmetric operator. This observation is applied to two concrete problems related to quantum mechanical systems. First, we give sharp estimates on the exponential decay of the resolvent and the single-particle density matrix for Schroedinger operators with spectral gaps. Second, we provide new ways of evaluating the resolvent norm for Schroedinger operators appearing in the complex scaling theory of resonances

Technical report: Electric field in not completely symmetric systems

International Nuclear Information System (INIS)

Vila, F.

1994-08-01

In this paper it is studied theoretically the electric field in the not completely symmetric system earthed metallic sphere-uniformly charged dielectric plan, for sphere surface points situated in the plan that contains sphere's center and vertical symmetry axe of dielectric plan. (author). 11 refs, 1 fig

On Split Lie Algebras with Symmetric Root Systems

Indian Academy of Sciences (India)

... and any I j a well described ideal of , satisfying [ I j , I k ] = 0 if j ≠ k . Under certain conditions, the simplicity of is characterized and it is shown that is the direct sum of the family of its minimal ideals, each one being a simple split Lie algebra with a symmetric root system and having all its nonzero roots connected.

On split Lie algebras with symmetric root systems

Indian Academy of Sciences (India)

ideal of L, satisfying [Ij ,Ik] = 0 if j = k. Under certain conditions, the simplicity of L is characterized and it is shown that L is the direct sum of the family of its minimal ideals, each one being a simple split Lie algebra with a symmetric root system and having all its nonzero roots connected. Keywords. Infinite dimensional Lie ...

The symmetric extendibility of quantum states

International Nuclear Information System (INIS)

Nowakowski, Marcin L

2016-01-01

Studies on the symmetric extendibility of quantum states have become particularly important in the context of the analysis of one-way quantum measures of entanglement, and the distillability and security of quantum protocols. In this paper we analyze composite systems containing a symmetric extendible part, with particular attention devoted to the one-way security of such systems. Further, we introduce a new one-way entanglement monotone based on the best symmetric approximation of a quantum state and the extendible number of a quantum state. We underpin these results with geometric observations about the structures of multi-party settings which posses substantial symmetric extendible components in their subspaces. The impossibility of reducing the maximal symmetric extendibility by means of the one-way local operations and classical communication method is pointed out on multiple copies. Finally, we state a conjecture linking symmetric extendibility with the one-way distillability and security of all quantum states, analyzing the behavior of a private key in the neighborhood of symmetric extendible states. (paper)

Symmetric positive differential equations and first order hyperbolic systems

International Nuclear Information System (INIS)

Tangmanee, S.

1981-12-01

We prove that under some conditions the first order hyperbolic system and its associated mixed initial boundary conditions considered, for example, in Kreiss (Math. Comp. 22, 703-704 (1968)) and Kreiss and Gustafsson (Math. Comp. 26, 649-686 (1972)), can be transformed into a symmetric positive system of P.D.E.'s with admissible boundary conditions of Friedrich's type (Comm. Pure Appl. Math 11, 333-418 (1958)). (author)

Thermal properties of self-gravitating plane-symmetric configuration

Energy Technology Data Exchange (ETDEWEB)

Hara, T; Ikeuchi, S [Kyoto Univ. (Japan). Dept. of Physics; Sugimoto, D

1976-09-01

As a limiting case of rotating stars, thermal properties of infinite plane-symmetric self-gravitating gas are investigated. Such a configuration is characterized by surface density of the plane instead of stellar mass. In the Kelvin contraction, temperature of the interior decreases, if the surface density is kept constant. If the accretion of matter takes place, or if the angular momenta are transferred outward, the surface density will increase. In this case, the temperature of the interior may increase. When a nuclear burning is ignited, it is thermally unstable in most cases, even when electrons are non-degenerate. This thermal instability is one of the essential differences of the plane-symmetric configuration from the spherical star. Such instabilities are computed for different cases of nuclear fuels. This type of nuclear instability is the same phenomenon as thermal instability of a thin shell burning in a spherical star.

Cloning of symmetric d-level photonic states in physical systems

International Nuclear Information System (INIS)

Fan Heng; Matsumoto, Keiji; Imai, Hiroshi; Weihs, Gregor

2002-01-01

Optimal procedures play an important role in quantum information. It turns out that some naturally occurring processes as emission of light from an atom can realize optimal transformations. Here we study how arbitrary symmetric states of a number of d-level systems can be cloned using a multilevel atomic system. It is shown that optimality is always ensured even though the output number of systems is probabilistic

Symmetric fusion of heavy ions around the Coulomb barrier energy

International Nuclear Information System (INIS)

Royer, G.; Remaud, B.

1983-01-01

Using the liquid drop model, we have performed a systematic study of the symmetric fusion with a neck degree of freedom and tunnelling effects, the nuclear potential being calculated with the proximity approach. Barrier heights and positions are in very good agreement with experimental data when they are known (light-medium systems); the recent experimental data of the reactions 58 Ni + 58 Ni and 64 Ni + 64 Ni are particularly investigated. For heavier systems double-humped fusion barriers and isomeric states are predicted which strongly limit the complete fusion probability

Analytical mass formula and nuclear surface properties in the ETF approximation. Part I: symmetric nuclei

Science.gov (United States)

Aymard, François; Gulminelli, Francesca; Margueron, Jérôme

2016-08-01

The problem of determination of nuclear surface energy is addressed within the framework of the extended Thomas Fermi (ETF) approximation using Skyrme functionals. We propose an analytical model for the density profiles with variationally determined diffuseness parameters. In this first paper, we consider the case of symmetric nuclei. In this situation, the ETF functional can be exactly integrated, leading to an analytical formula expressing the surface energy as a function of the couplings of the energy functional. The importance of non-local terms is stressed and it is shown that they cannot be deduced simply from the local part of the functional, as it was suggested in previous works.

Admissible perturbations and false instabilities in PT -symmetric quantum systems

Science.gov (United States)

Znojil, Miloslav

2018-03-01

One of the most characteristic mathematical features of the PT -symmetric quantum mechanics is the explicit Hamiltonian dependence of its physical Hilbert space of states H =H (H ) . Some of the most important physical consequences are discussed, with emphasis on the dynamical regime in which the system is close to phase transition. Consistent perturbation treatment of such a regime is proposed. An illustrative application of the innovated perturbation theory to a non-Hermitian but PT -symmetric user-friendly family of J -parametric "discrete anharmonic" quantum Hamiltonians H =H (λ ⃗) is provided. The models are shown to admit the standard probabilistic interpretation if and only if the parameters remain compatible with the reality of the spectrum, λ ⃗∈D(physical ) . In contradiction to conventional wisdom, the systems are then shown to be stable with respect to admissible perturbations, inside the domain D(physical ), even in the immediate vicinity of the phase-transition boundaries ∂ D(physical ) .

Multiparty symmetric sum types

DEFF Research Database (Denmark)

Nielsen, Lasse; Yoshida, Nobuko; Honda, Kohei

2010-01-01

This paper introduces a new theory of multiparty session types based on symmetric sum types, by which we can type non-deterministic orchestration choice behaviours. While the original branching type in session types can represent a choice made by a single participant and accepted by others...... determining how the session proceeds, the symmetric sum type represents a choice made by agreement among all the participants of a session. Such behaviour can be found in many practical systems, including collaborative workflow in healthcare systems for clinical practice guidelines (CPGs). Processes...... with the symmetric sums can be embedded into the original branching types using conductor processes. We show that this type-driven embedding preserves typability, satisfies semantic soundness and completeness, and meets the encodability criteria adapted to the typed setting. The theory leads to an efficient...

Symmetrical components and power analysis for a two-phase microgrid system

DEFF Research Database (Denmark)

Alibeik, M.; Santos Jr., E. C. dos; Blaabjerg, Frede

2014-01-01

This paper presents a mathematical model for the symmetrical components and power analysis of a new microgrid system consisting of three wires and two voltages in quadrature, which is designated as a two-phase microgrid. The two-phase microgrid presents the following advantages: 1) constant power...

Symmetric and Asymmetric Tendencies in Stable Complex Systems.

Science.gov (United States)

Tan, James P L

2016-08-22

A commonly used approach to study stability in a complex system is by analyzing the Jacobian matrix at an equilibrium point of a dynamical system. The equilibrium point is stable if all eigenvalues have negative real parts. Here, by obtaining eigenvalue bounds of the Jacobian, we show that stable complex systems will favor mutualistic and competitive relationships that are asymmetrical (non-reciprocative) and trophic relationships that are symmetrical (reciprocative). Additionally, we define a measure called the interdependence diversity that quantifies how distributed the dependencies are between the dynamical variables in the system. We find that increasing interdependence diversity has a destabilizing effect on the equilibrium point, and the effect is greater for trophic relationships than for mutualistic and competitive relationships. These predictions are consistent with empirical observations in ecology. More importantly, our findings suggest stabilization algorithms that can apply very generally to a variety of complex systems.

Mathematical Model of Induction Heating Processes in Axial Symmetric Inductor-Detail Systems

Directory of Open Access Journals (Sweden)

Maik Streblau

2014-05-01

Full Text Available The wide variety of models for analysis of processes in the inductor-detail systems makes it necessary to summarize them. This is a difficult task because of the variety of inductor-detail system configurations. This paper aims to present a multi physics mathematical model for complex analysis of electromagnetic and thermal fields in axial symmetric systems inductor-detail.

Causal symmetric spaces

CERN Document Server

Olafsson, Gestur; Helgason, Sigurdur

1996-01-01

This book is intended to introduce researchers and graduate students to the concepts of causal symmetric spaces. To date, results of recent studies considered standard by specialists have not been widely published. This book seeks to bring this information to students and researchers in geometry and analysis on causal symmetric spaces.Includes the newest results in harmonic analysis including Spherical functions on ordered symmetric space and the holmorphic discrete series and Hardy spaces on compactly casual symmetric spacesDeals with the infinitesimal situation, coverings of symmetric spaces, classification of causal symmetric pairs and invariant cone fieldsPresents basic geometric properties of semi-simple symmetric spacesIncludes appendices on Lie algebras and Lie groups, Bounded symmetric domains (Cayley transforms), Antiholomorphic Involutions on Bounded Domains and Para-Hermitian Symmetric Spaces

Random matrix ensembles for PT-symmetric systems

International Nuclear Information System (INIS)

Graefe, Eva-Maria; Mudute-Ndumbe, Steve; Taylor, Matthew

2015-01-01

Recently much effort has been made towards the introduction of non-Hermitian random matrix models respecting PT-symmetry. Here we show that there is a one-to-one correspondence between complex PT-symmetric matrices and split-complex and split-quaternionic versions of Hermitian matrices. We introduce two new random matrix ensembles of (a) Gaussian split-complex Hermitian; and (b) Gaussian split-quaternionic Hermitian matrices, of arbitrary sizes. We conjecture that these ensembles represent universality classes for PT-symmetric matrices. For the case of 2 × 2 matrices we derive analytic expressions for the joint probability distributions of the eigenvalues, the one-level densities and the level spacings in the case of real eigenvalues. (fast track communication)

Doubly Fed Induction Generator Wind Turbine Systems Subject to Recurring Symmetrical Grid Faults

DEFF Research Database (Denmark)

Chen, Wenjie; Blaabjerg, Frede; Zhu, Nan

2016-01-01

New grid codes demand the wind turbine systems to ride through recurring grid faults. In this paper, the performance of the doubly Ffed induction generator (DFIG) wind turbine system under recurring symmetrical grid faults is analyzed. The mathematical model of the DFIG under recurring symmetrical...... grid faults is established. The analysis is based on the DFIG wind turbine system with the typical low-voltage ride-through strategy-with rotor-side crowbar. The stator natural flux produced by the voltage recovery after the first grid fault may be superposed on the stator natural flux produced...... by the second grid fault, so that the transient rotor and stator current and torque fluctuations under the second grid fault may be influenced by the characteristic of the first grid fault, including the voltage dips level and the grid fault angle, as well as the duration between two faults. The mathematical...

Symmetric, discrete fractional splines and Gabor systems

DEFF Research Database (Denmark)

Søndergaard, Peter Lempel

2006-01-01

In this paper we consider fractional splines as windows for Gabor frames. We introduce two new types of symmetric, fractional splines in addition to one found by Unser and Blu. For the finite, discrete case we present two families of splines: One is created by sampling and periodizing the continu......In this paper we consider fractional splines as windows for Gabor frames. We introduce two new types of symmetric, fractional splines in addition to one found by Unser and Blu. For the finite, discrete case we present two families of splines: One is created by sampling and periodizing...... the continuous splines, and one is a truly finite, discrete construction. We discuss the properties of these splines and their usefulness as windows for Gabor frames and Wilson bases....

From nuclear reactions to neutron stars

Indian Academy of Sciences (India)

2014-04-30

Apr 30, 2014 ... An equation of state (EoS) for symmetric nuclear matter is constructed using the density-dependent M3Y effective interaction and extended for isospin asymmetric nuclear matter. Theoretically obtained values of symmetric nuclear matter incompressibility, isobaric incompressibility, symmetry energy and its ...

Nuclear Spin Relaxation

Indian Academy of Sciences (India)

IAS Admin

ments have shown that in some cases the nuclear spin systems may be held in special configurations called .... these methods have been commercialized, and used for clinical trials, in which hyperpolarized NMR is used to .... symmetric under exchange, meaning that exchanging the two nuclei leaves the state unchanged.

Topologically protected bound states in photonic parity-time-symmetric crystals.

Science.gov (United States)

Weimann, S; Kremer, M; Plotnik, Y; Lumer, Y; Nolte, S; Makris, K G; Segev, M; Rechtsman, M C; Szameit, A

2017-04-01

Parity-time (PT)-symmetric crystals are a class of non-Hermitian systems that allow, for example, the existence of modes with real propagation constants, for self-orthogonality of propagating modes, and for uni-directional invisibility at defects. Photonic PT-symmetric systems that also support topological states could be useful for shaping and routing light waves. However, it is currently debated whether topological interface states can exist at all in PT-symmetric systems. Here, we show theoretically and demonstrate experimentally the existence of such states: states that are localized at the interface between two topologically distinct PT-symmetric photonic lattices. We find analytical closed form solutions of topological PT-symmetric interface states, and observe them through fluorescence microscopy in a passive PT-symmetric dimerized photonic lattice. Our results are relevant towards approaches to localize light on the interface between non-Hermitian crystals.

3He/4He production ratios by tetrahedral symmetric condensation

International Nuclear Information System (INIS)

Takahashi, Akito

2006-01-01

The present paper treats application of the Electronic Quasi-Particle Expansion Theory (EQPET) model for Tetrahedral Symmetric Condensate (TSC) of H/D mixed systems for Pd host metal. Production ratios of 3 He/ 4 He for multi-body fusion reactions in H/D mixed TSC systems are calculated as a function of H/D mixing ratio. The model is further extended to treat direct nuclear interactions between host-metal nucleus and TSC of pure four protons (or four deuterons), since TSC can become very small (far less than 1 pm radius) charge-neutral pseudo-particle. Results for the case of Ni + 4p/TSC are discussed with Ni + p capture reactions and Ni + 4p fission reactions. (authors)

Rodrigues formulas for the non-symmetric multivariable polynomials associated with the BCN-type root system

International Nuclear Information System (INIS)

Nishino, Akinori; Ujino, Hideaki; Komori, Yasushi; Wadati, Miki

2000-01-01

The non-symmetric Macdonald-Koornwinder polynomials are joint eigenfunctions of the commuting Cherednik operators which are constructed from the representation theory for the affine Hecke algebra corresponding to the BC N -type root system. We present the Rodrigues formula for the non-symmetric Macdonald-Koornwinder polynomials. The raising operators are derived from the realizations of the corresponding double affine Hecke algebra. In the quasi-classical limit, the above theory reduces to that of the BC N -type Sutherland model which describes many particles with inverse-square long-range interactions on a circle with one impurity. We also present the Rodrigues formula for the non-symmetric Jacobi polynomials of type BC N which are eigenstates of the BC N -type Sutherland model

Symmetric low-voltage powering system for relativistic electronic devices

International Nuclear Information System (INIS)

Agafonov, A.V.; Lebedev, A.N.; Krastelev, E.G.

2005-01-01

A special driver for double-sided powering of relativistic magnetrons and several methods of localized electron flow forming in the interaction region of relativistic magnetrons are proposed and discussed. Two experimental installations are presented and discussed. One of them is designed for laboratory research and demonstration experiments at a rather low voltage. The other one is a prototype of a full-scale installation for an experimental research at relativistic levels of voltages on the microwave generation in the new integrated system consisting of a relativistic magnetron and symmetrical induction driver

Symmetric normalisation for intuitionistic logic

DEFF Research Database (Denmark)

Guenot, Nicolas; Straßburger, Lutz

2014-01-01

We present two proof systems for implication-only intuitionistic logic in the calculus of structures. The first is a direct adaptation of the standard sequent calculus to the deep inference setting, and we describe a procedure for cut elimination, similar to the one from the sequent calculus......, but using a non-local rewriting. The second system is the symmetric completion of the first, as normally given in deep inference for logics with a DeMorgan duality: all inference rules have duals, as cut is dual to the identity axiom. We prove a generalisation of cut elimination, that we call symmetric...

Randomized Symmetric Crypto Spatial Fusion Steganographic System

Directory of Open Access Journals (Sweden)

Viswanathan Perumal

2016-06-01

Full Text Available The image fusion steganographic system embeds encrypted messages in decomposed multimedia carriers using a pseudorandom generator but it fails to evaluate the contents of the cover image. This results in the secret data being embedded in smooth regions, which leads to visible distortion that affects the imperceptibility and confidentiality. To solve this issue, as well as to improve the quality and robustness of the system, the Randomized Symmetric Crypto Spatial Fusion Steganography System is proposed in this study. It comprises three-subsystem bitwise encryption, spatial fusion, and bitwise embedding. First, bitwise encryption encrypts the message using bitwise operation to improve the confidentiality. Then, spatial fusion decomposes and evaluates the region of embedding on the basis of sharp intensity and capacity. This restricts the visibility of distortion and provides a high embedding capacity. Finally, the bitwise embedding system embeds the encrypted message through differencing the pixels in the region by 1, checking even or odd options and not equal to zero constraints. This reduces the modification rate to avoid distortion. The proposed heuristic algorithm is implemented in the blue channel, to which the human visual system is less sensitive. It was tested using standard IST natural images with steganalysis algorithms and resulted in better quality, imperceptibility, embedding capacity and invulnerability to various attacks compared to other steganographic systems.

Iterative methods for the solution of very large complex symmetric linear systems of equations in electrodynamics

Energy Technology Data Exchange (ETDEWEB)

Clemens, M.; Weiland, T. [Technische Hochschule Darmstadt (Germany)

1996-12-31

In the field of computational electrodynamics the discretization of Maxwell`s equations using the Finite Integration Theory (FIT) yields very large, sparse, complex symmetric linear systems of equations. For this class of complex non-Hermitian systems a number of conjugate gradient-type algorithms is considered. The complex version of the biconjugate gradient (BiCG) method by Jacobs can be extended to a whole class of methods for complex-symmetric algorithms SCBiCG(T, n), which only require one matrix vector multiplication per iteration step. In this class the well-known conjugate orthogonal conjugate gradient (COCG) method for complex-symmetric systems corresponds to the case n = 0. The case n = 1 yields the BiCGCR method which corresponds to the conjugate residual algorithm for the real-valued case. These methods in combination with a minimal residual smoothing process are applied separately to practical 3D electro-quasistatical and eddy-current problems in electrodynamics. The practical performance of the SCBiCG methods is compared with other methods such as QMR and TFQMR.

Centrioles in Symmetric Spaces

OpenAIRE

Quast, Peter

2011-01-01

We describe all centrioles in irreducible simply connected pointed symmetric spaces of compact type in terms of the root system of the ambient space, and we study some geometric properties of centrioles.

Potential surfaces in symmetric heavy-ion reactions

International Nuclear Information System (INIS)

Royer, G.; Piller, C.; Mignen, J.; Raffray, Y.

1989-01-01

The entrance channel in symmetric heavy-ion reactions is studied in the liquid-drop model approach including the nuclear proximity energy and allowing ellipsoidal deformations of the colliding nuclei. In the whole mass range a sudden transition occurs from oblate to prolate shapes when the proximity forces become important. This strongly affects the effective moment of inertia. The ellipsoidal deformations reduce the fusion barrier width for light systems and lower the potential barrier height for medium and heavy nuclei. The results are in agreement with the empirical effective barrier shift determined by Aguiar et al for the 58 Ni + 58 Ni, 74 Ge + 74 Ge and 80 Se + 80 Se systems. The sub-barrier fusion enhancement in heavy-ion reactions might be explained by the slowness of the process. Below the static fusion barrier, the reaction time is long; allowing some adiabaticity and deformations of the colliding ions. Above the barrier, the reaction is more sudden and the deformation degree of freedom is frozen

Electric field of not completely symmetric systems earthed sphere-uniformly charged dielectric plan

International Nuclear Information System (INIS)

Vila, F.

1994-07-01

In this paper we study theoretically the electric field in the not completely symmetric system, earthed metallic sphere-uniformly charged dielectric plan, for sphere surface points situated in the plan that contains sphere's center and vertical symmetry axe of dielectric plan. (author). 11 refs, 1 fig

Symmetric cryptographic protocols

CERN Document Server

Ramkumar, Mahalingam

2014-01-01

This book focuses on protocols and constructions that make good use of symmetric pseudo random functions (PRF) like block ciphers and hash functions - the building blocks for symmetric cryptography. Readers will benefit from detailed discussion of several strategies for utilizing symmetric PRFs. Coverage includes various key distribution strategies for unicast, broadcast and multicast security, and strategies for constructing efficient digests of dynamic databases using binary hash trees.   •        Provides detailed coverage of symmetric key protocols •        Describes various applications of symmetric building blocks •        Includes strategies for constructing compact and efficient digests of dynamic databases

Pseudo-Goldstone modes in isospin-asymmetric nuclear matter

International Nuclear Information System (INIS)

Cohen, T.D.; Broniowski, W.

1995-01-01

The authors analyze the chiral limit in dense isospin-asymmetric nuclear matter. It is shown that the pseudo-Goldstone modes in this system are qualitatively different from the case of isospin-symmetric matter

Stress analysis program system for nuclear vessel: STANSAS

International Nuclear Information System (INIS)

Okamoto, Asao; Michikami, Shinsuke

1979-01-01

IHI has developed a computer system of stress analysis and evaluation for nuclear vessels: STANSAS (STress ANalysis System for Axi-symmetric Structure). The system consists of more than twenty independent programs divided into the following six parts. 1. Programs for opening design by code rule. 2. Calculation model generating programs. 3. Load defining programs. 4. Structural analysis programs. 5. Load data/calculation results plotting programs. 6. Stress evaluation programs. Each program is connected with its pre- or post-processor through three data-bases which enable automatic data transfer. The user can make his choice of structural analysis programs in accordance with the problem to be solved. The interface to STANSAS can be easily installed in generalized structural analysis programs such as NASTRAN and MARC. For almost all tables and figures in the stress report, STANSAS has the function to print or plot out. The complicated procedures of ''Design by Analysis'' for pressure vessels have been well standardized by STANSAS. The system will give a high degree of efficiency and confidence to the design work. (author)

System of end-to-end symmetric database encryption

Science.gov (United States)

Galushka, V. V.; Aydinyan, A. R.; Tsvetkova, O. L.; Fathi, V. A.; Fathi, D. V.

2018-05-01

The article is devoted to the actual problem of protecting databases from information leakage, which is performed while bypassing access control mechanisms. To solve this problem, it is proposed to use end-to-end data encryption, implemented at the end nodes of an interaction of the information system components using one of the symmetric cryptographic algorithms. For this purpose, a key management method designed for use in a multi-user system based on the distributed key representation model, part of which is stored in the database, and the other part is obtained by converting the user's password, has been developed and described. In this case, the key is calculated immediately before the cryptographic transformations and is not stored in the memory after the completion of these transformations. Algorithms for registering and authorizing a user, as well as changing his password, have been described, and the methods for calculating parts of a key when performing these operations have been provided.

SP(6) X SU(2) and SO(8) X SU(2) - symmetric fermion-dynamic model of multinucleon systems

International Nuclear Information System (INIS)

Baktybaev, K.

2007-01-01

In last years a new approach describing collective states of multinucleon system on the base of their fermion dynamic symmetry was developed. Such fermion model is broad and logical one in comparison with the phenomenological model of interacting bosons. In cut fermion S- and D- pair spaces complicated nucleons interactions are approximating in that way so multinucleon system Hamiltonian becomes a simple function of fermion generators forming corresponding Lie algebra. Correlation fermion pairs are structured in such form so its operators of birth and destruction together with a set multiband operators are formed Sp(6) and SO(8) algebra of these pairs and SU(2)-algebra for so named anomalous pairs. For convenience at the model practical application to concrete systems the dynamical-symmetric Hamiltonian is writing by means of independent Casimir operators of subgroup are reductions of a large group. It is revealed, that observed Hamiltonians besides the known SU 3 , and SO 6 asymptotic borders have also more complicated 'vibration-like' borders SO 7 , SO 5 XSU 2 and SU 2 XSO 3 . In the paper both advantages and disadvantages of these borders and some its applications to specific nuclear systems are discussing

Non-skew-symmetric classical r-matrices, algebraic Bethe ansatz, and Bardeen-Cooper-Schrieffer-type integrable systems

International Nuclear Information System (INIS)

Skrypnyk, T.

2009-01-01

We construct quantum integrable systems associated with non-skew-symmetric gl(2)-valued classical r-matrices. We find a new explicit multiparametric family of such the non-skew-symmetric classical r-matrices. We consider two classes of examples of the corresponding integrable systems, namely generalized Gaudin systems with and without an external magnetic field. In the case of arbitrary r-matrices diagonal in a standard gl(2)-basis, we calculate the spectrum of the corresponding quantum integrable systems using the algebraic Bethe ansatz. We apply these results to a construction of integrable fermionic models and obtain a wide class of integrable Bardeen-Cooper-Schrieffer (BCS)-type fermionic Hamiltonians containing the pairing and electrostatic interaction terms. We also consider special cases when the corresponding integrable Hamiltonians contain only pairing interaction term and are exact analogs of the 'reduced BCS Hamiltonian' of Richardson

Mixed problems for linear symmetric hyperbolic systems with characteristic boundary conditions

International Nuclear Information System (INIS)

Secchi, P.

1994-01-01

We consider the initial-boundary value problem for symmetric hyperbolic systems with characteristic boundary of constant multiplicity. In the linear case we give some results about the existence of regular solutions in suitable functions spaces which take in account the loss of regularity in the normal direction to the characteristic boundary. We also consider the equations of ideal magneto-hydrodynamics under perfectly conducting wall boundary conditions and give some results about the solvability of such mixed problem. (author). 16 refs

On Symmetric Polynomials

OpenAIRE

Golden, Ryan; Cho, Ilwoo

2015-01-01

In this paper, we study structure theorems of algebras of symmetric functions. Based on a certain relation on elementary symmetric polynomials generating such algebras, we consider perturbation in the algebras. In particular, we understand generators of the algebras as perturbations. From such perturbations, define injective maps on generators, which induce algebra-monomorphisms (or embeddings) on the algebras. They provide inductive structure theorems on algebras of symmetric polynomials. As...

Symmetrization of Facade Layouts

KAUST Repository

Jiang, Haiyong; Yan, Dong-Ming; Dong, Weiming; Wu, Fuzhang; Nan, Liangliang; Zhang, Xiaopeng

2016-01-01

We present an automatic approach for symmetrizing urban facade layouts. Our method can generate a symmetric layout through minimally modifying the original input layout. Based on the principles of symmetry in urban design, we formulate facade layout symmetrization as an optimization problem. Our method further enhances the regularity of the final layout by redistributing and aligning elements in the layout. We demonstrate that the proposed solution can effectively generate symmetric facade layouts.

Symmetrization of Facade Layouts

KAUST Repository

Jiang, Haiyong

2016-02-26

We present an automatic approach for symmetrizing urban facade layouts. Our method can generate a symmetric layout through minimally modifying the original input layout. Based on the principles of symmetry in urban design, we formulate facade layout symmetrization as an optimization problem. Our method further enhances the regularity of the final layout by redistributing and aligning elements in the layout. We demonstrate that the proposed solution can effectively generate symmetric facade layouts.

Uniqueness of flat spherically symmetric spacelike hypersurfaces admitted by spherically symmetric static spacetimes

Science.gov (United States)

Beig, Robert; Siddiqui, Azad A.

2007-11-01

It is known that spherically symmetric static spacetimes admit a foliation by flat hypersurfaces. Such foliations have explicitly been constructed for some spacetimes, using different approaches, but none of them have proved or even discussed the uniqueness of these foliations. The issue of uniqueness becomes more important due to suitability of flat foliations for studying black hole physics. Here, flat spherically symmetric spacelike hypersurfaces are obtained by a direct method. It is found that spherically symmetric static spacetimes admit flat spherically symmetric hypersurfaces, and that these hypersurfaces are unique up to translation under the timelike Killing vector. This result guarantees the uniqueness of flat spherically symmetric foliations for such spacetimes.

Performance limitations of translationally symmetric nonimaging devices

Science.gov (United States)

Bortz, John C.; Shatz, Narkis E.; Winston, Roland

2001-11-01

The component of the optical direction vector along the symmetry axis is conserved for all rays propagated through a translationally symmetric optical device. This quality, referred to herein as the translational skew invariant, is analogous to the conventional skew invariant, which is conserved in rotationally symmetric optical systems. The invariance of both of these quantities is a consequence of Noether's theorem. We show how performance limits for translationally symmetric nonimaging optical devices can be derived from the distributions of the translational skew invariant for the optical source and for the target to which flux is to be transferred. Examples of computed performance limits are provided. In addition, we show that a numerically optimized non-tracking solar concentrator utilizing symmetry-breaking surface microstructure can overcome the performance limits associated with translational symmetry. The optimized design provides a 47.4% increase in efficiency and concentration relative to an ideal translationally symmetric concentrator.

Parallel coupling of symmetric and asymmetric exclusion processes

International Nuclear Information System (INIS)

Tsekouras, K; Kolomeisky, A B

2008-01-01

A system consisting of two parallel coupled channels where particles in one of them follow the rules of totally asymmetric exclusion processes (TASEP) and in another one move as in symmetric simple exclusion processes (SSEP) is investigated theoretically. Particles interact with each other via hard-core exclusion potential, and in the asymmetric channel they can only hop in one direction, while on the symmetric lattice particles jump in both directions with equal probabilities. Inter-channel transitions are also allowed at every site of both lattices. Stationary state properties of the system are solved exactly in the limit of strong couplings between the channels. It is shown that strong symmetric couplings between totally asymmetric and symmetric channels lead to an effective partially asymmetric simple exclusion process (PASEP) and properties of both channels become almost identical. However, strong asymmetric couplings between symmetric and asymmetric channels yield an effective TASEP with nonzero particle flux in the asymmetric channel and zero flux on the symmetric lattice. For intermediate strength of couplings between the lattices a vertical-cluster mean-field method is developed. This approximate approach treats exactly particle dynamics during the vertical transitions between the channels and it neglects the correlations along the channels. Our calculations show that in all cases there are three stationary phases defined by particle dynamics at entrances, at exits or in the bulk of the system, while phase boundaries depend on the strength and symmetry of couplings between the channels. Extensive Monte Carlo computer simulations strongly support our theoretical predictions. Theoretical calculations and computer simulations predict that inter-channel couplings have a strong effect on stationary properties. It is also argued that our results might be relevant for understanding multi-particle dynamics of motor proteins

A semi-symmetric image encryption scheme based on the function projective synchronization of two hyperchaotic systems.

Directory of Open Access Journals (Sweden)

Xiaoqiang Di

Full Text Available Both symmetric and asymmetric color image encryption have advantages and disadvantages. In order to combine their advantages and try to overcome their disadvantages, chaos synchronization is used to avoid the key transmission for the proposed semi-symmetric image encryption scheme. Our scheme is a hybrid chaotic encryption algorithm, and it consists of a scrambling stage and a diffusion stage. The control law and the update rule of function projective synchronization between the 3-cell quantum cellular neural networks (QCNN response system and the 6th-order cellular neural network (CNN drive system are formulated. Since the function projective synchronization is used to synchronize the response system and drive system, Alice and Bob got the key by two different chaotic systems independently and avoid the key transmission by some extra security links, which prevents security key leakage during the transmission. Both numerical simulations and security analyses such as information entropy analysis, differential attack are conducted to verify the feasibility, security, and efficiency of the proposed scheme.

In-Medium K^+ Electromagnetic Form Factor with a Symmetric Vertex in a Light Front Approach

Science.gov (United States)

Yabusaki, George H. S.; de Melo, J. P. B. C.; de Paula, Wayne; Tsushima, K.; Frederico, T.

2018-05-01

Using the light-front K^ +-Meson wave function based on a Bethe-Salpeter amplitude model for the Quark-Antiquark bound state, we study the Electromagnetic Form Factor (EMFF) of the K^ +-Meson in nuclear medium within the framework of light-front field theory. The K^ +-Meson model we adopt is well constrained by previous and recent studies to explain its properties in vacuum. The in-medium K^ +-Meson EMFF is evaluated for the plus-component of the electromagnetic current, J^+, in the Breit frame. In order to consistently incorporate the constituent up and antistrange Quarks of the K^ +-Meson immersed in symmetric nuclear matter, we use the Quark-Meson coupling model, which has been widely applied to various hadronic and nuclear phenomena in a nuclear medium with success. We predict the in-medium modification of the K^ +-Meson EMFF in symmetric nuclear matter. It is found that, after a fine tuning of the regulator mass, i.e. m_R = 0.600 GeV, the model is suitable to fit the available experimental data in vacuum within the theoretical uncertainties, and based on this we predict the in-medium modification of the K^ +-Meson EMFF.

A Non-symmetric Digital Image Secure Communication Scheme Based on Generalized Chaos Synchronization System

International Nuclear Information System (INIS)

Zhang Xiaohong; Min Lequan

2005-01-01

Based on a generalized chaos synchronization system and a discrete Sinai map, a non-symmetric true color (RGB) digital image secure communication scheme is proposed. The scheme first changes an ordinary RGB digital image with 8 bits into unrecognizable disorder codes and then transforms the disorder codes into an RGB digital image with 16 bits for transmitting. A receiver uses a non-symmetric key to verify the authentication of the received data origin, and decrypts the ciphertext. The scheme can encrypt and decrypt most formatted digital RGB images recognized by computers, and recover the plaintext almost without any errors. The scheme is suitable to be applied in network image communications. The analysis of the key space, sensitivity of key parameters, and correlation of encrypted images imply that this scheme has sound security.

Young—Capelli symmetrizers in superalgebras†

Science.gov (United States)

Brini, Andrea; Teolis, Antonio G. B.

1989-01-01

Let Supern[U [unk] V] be the nth homogeneous subspace of the supersymmetric algebra of U [unk] V, where U and V are Z2-graded vector spaces over a field K of characteristic zero. The actions of the general linear Lie superalgebras pl(U) and pl(V) span two finite-dimensional K-subalgebras B and [unk] of EndK(Supern[U [unk] V]) that are the centralizers of each other. Young—Capelli symmetrizers and Young—Capelli *-symmetrizers give rise to K-linear bases of B and [unk] containing orthogonal systems of idempotents; thus they yield complete decompositions of B and [unk] into minimal left and right ideals, respectively. PMID:16594014

Stationary states of a PT symmetric two-mode Bose–Einstein condensate

International Nuclear Information System (INIS)

Graefe, Eva-Maria

2012-01-01

The understanding of nonlinear PT symmetric quantum systems, arising for example in the theory of Bose–Einstein condensates in PT symmetric potentials, is widely based on numerical investigations, and little is known about generic features induced by the interplay of PT symmetry and nonlinearity. To gain deeper insights it is important to have analytically solvable toy models at hand. In the present paper the stationary states of a simple toy model of a PT symmetric system previously introduced in [1, 2] are investigated. The model can be interpreted as a simple description of a Bose–Einstein condensate in a PT symmetric double well trap in a two-mode approximation. The eigenvalues and eigenstates of the system can be explicitly calculated in a straightforward manner; the resulting structures resemble those that have recently been found numerically for a more realistic PT symmetric double delta potential. In addition, a continuation of the system is introduced that allows an interpretation in terms of a simple linear matrix model. This article is part of a special issue of Journal of Physics A: Mathematical and Theoretical devoted to ‘Quantum physics with non-Hermitian operators’. (paper)

Symmetric q-Bessel functions

Directory of Open Access Journals (Sweden)

Giuseppe Dattoli

1996-05-01

Full Text Available q analog of bessel functions, symmetric under the interchange of q and q^ −1 are introduced. The definition is based on the generating function realized as product of symmetric q-exponential functions with appropriate arguments. Symmetric q-Bessel function are shown to satisfy various identities as well as second-order q-differential equations, which in the limit q → 1 reproduce those obeyed by the usual cylindrical Bessel functions. A brief discussion on the possible algebraic setting for symmetric q-Bessel functions is also provided.

Boiling Patterns of Iso-asymmetric Nuclear Matter

International Nuclear Information System (INIS)

Tõke, Jan

2013-01-01

Limits of thermodynamic metastability of self-bound neutron-rich nuclear matter are explored within the framework of microcanonical thermodynamics of interacting Fermi Gas model in Thomas-Fermi approximation. It is found that as the excitation energy per nucleon of the system is increased beyond a certain limiting value, the system loses metastability and becomes unstable with respect to joint fluctuations in excitation energy per nucleon and in isospin per nucleon. As a result, part of the system is forced to boil off in a form of iso-rich non-equilibrated vapors. Left behind in such a process, identifiable with distillation, is a more iso-symmetric metastable residue at a temperature characteristic of its residual isospin content. With a progressing increase in the initial excitation energy per nucleon, more neutron-rich matter is boiled off and a more iso-symmetric residue is left behind with progressively increasing characteristic temperature. Eventually, when all excess neutrons are shed, the system boils uniformly with a further supply of excitation energy, leaving behind a smaller and smaller residue at a characteristic boiling-point temperature of iso-symmetric matter.

Helically symmetric experiment, (HSX) goals, design and status

International Nuclear Information System (INIS)

Anderson, F.S.B.; Almagri, A.F.; Anderson, D.T.; Matthews, P.G.; Talmadge, J.N.; Shohet, J.L.

1995-01-01

HSX is a quasi-helically symmetric (QHS) stellarator currently under construction at the Torsatron-Stellarator Laboratory of the University of Wisconsin-Madison. This device is unique in its magnetic design in that the magnetic field spectrum possesses only a single dominant (helical) component. This design avoids the large direct orbit losses and the low-collisionality neoclassical losses associated with conventional stellarators. The restoration of symmetry to the confining magnetic field makes the neoclassical confinement in this device analogous to an axisymmetric q=1/3 tokamak. The HSX device has been designed with a clear set of primary physics goals: demonstrate the feasibility of construction of a QHS device, examine single particle confinement of injected ions with regard to magnetic field symmetry breaking, compare density and temperature profiles in this helically symmetric system to those for axisymmetric tokamaks and conventional stellarators, examine electric fields and plasma rotation with edge biasing in relation to L-H transitions in symmetric versus non-symmetric stellarator systems, investigate QHS effects on 1/v regime electron confinement, and examine how greatly-reduced neoclassical electron thermal conductivity compares to the experimental χ e profile. 3 refs., 4 figs., 1 tab

Strong orientational coordinates and orientational order parameters for symmetric objects

International Nuclear Information System (INIS)

Haji-Akbari, Amir; Glotzer, Sharon C

2015-01-01

Recent advancements in the synthesis of anisotropic macromolecules and nanoparticles have spurred an immense interest in theoretical and computational studies of self-assembly. The cornerstone of such studies is the role of shape in self-assembly and in inducing complex order. The problem of identifying different types of order that can emerge in such systems can, however, be challenging. Here, we revisit the problem of quantifying orientational order in systems of building blocks with non-trivial rotational symmetries. We first propose a systematic way of constructing orientational coordinates for such symmetric building blocks. We call the arising tensorial coordinates strong orientational coordinates (SOCs) as they fully and exclusively specify the orientation of a symmetric object. We then use SOCs to describe and quantify local and global orientational order, and spatiotemporal orientational correlations in systems of symmetric building blocks. The SOCs and the orientational order parameters developed in this work are not only useful in performing and analyzing computer simulations of symmetric molecules or particles, but can also be utilized for the efficient storage of rotational information in long trajectories of evolving many-body systems. (paper)

Analytical Study on Propagation Dynamics of Optical Beam in Parity-Time Symmetric Optical Couplers

International Nuclear Information System (INIS)

Zhou Zheng; Zhang Li-Juan; Zhu Bo

2015-01-01

We present exact analytical solutions to parity-time (PT) symmetric optical system describing light transport in PT-symmetric optical couplers. We show that light intensity oscillates periodically between two waveguides for unbroken PT-symmetric phase, whereas light always leaves the system from the waveguide experiencing gain when light is initially input at either waveguide experiencing gain or waveguide experiencing loss for broken PT-symmetric phase. These analytical results agree with the recent experimental observation reported by Rüter et al. [Nat. Phys. 6 (2010) 192]. Besides, we present a scheme for manipulating PT symmetry by applying a periodic modulation. Our results provide an efficient way to control light propagation in periodically modulated PT-symmetric system by tuning the modulation amplitude and frequency. (paper)

Dynamical instabilities in hot expanding nuclear systems: a microscopic approach to the understanding of multifragmentation

International Nuclear Information System (INIS)

Suraud, E.

1989-01-01

We present a microscopic study of the quasi-fusion/explosion transition in the framework of Landau-Vlasov simulations and for intermediate energy heavy-ion collisions (beam energy from 10 to 100 MeV/A). After a short presentation of the results of schematic calculations, which furnish a guideline for microscopic investigations, we discuss the relevance of our approach for studying multifragmentation. Once the limitations of this kind of dynamical simulations exhibited, we perform a detailed analysis in terms of the equation of state of the system. In agreement with schematic models we find that the composite nuclear system formed in the collision actually explodes when it stays long enough in the mechanically unstable region (spinodal region). Quantitative estimates of the explosion threshold are given for central symmetric reactions (Ca + Ca and Ar + Ti). The link of the results with transport properties and the equation of state of nuclear matter are briefly discussed

The effect of axial loads on free vibration of symmetric frame structures using continuous system method

Directory of Open Access Journals (Sweden)

Elham Ghandi

2016-09-01

Full Text Available The free vibration of frame structures has been usually studied in literature without considering the effect of axial loads. In this paper, the continuous system method is employed to investigate this effect on the free flexural and torsional vibration of two and three dimensional symmetric frames. In the continuous system method, in approximate analysis of buildings, commonly, the structure is replaced by an equivalent beam which matches the dominant characteristics of the structure. Accordingly, the natural frequencies of the symmetric frame structures are obtained through solving the governing differential equation of the equivalent beam whose stiffness and mass are supposed to be uniformly distributed along the length. The corresponding axial load applied to the replaced beam is calculated based on the total weight and the number of stories of the building. A numerical example is presented to show the simplicity and efficiency of the proposed solution.

Forced vibration of nonlinear system with symmetrical piecewise-linear characteristics

International Nuclear Information System (INIS)

Watanabe, Takeshi

1983-01-01

It is fairly difficult to treat exactly the analysis of a vibrating system including some play because it is accompanied by a strong nonlinear phenomenon of collision. The author attempted the theoretical analysis by the exact solution using series solution and the approximate solution, treating the forced vibration of a system having some play as the forced vibration of a continuous system with nonlinear boundary condition or the colliding vibration of a continuum. In this report, the problem of such system with play is treated as a nonlinear system having the symmetrical, piecewise linear characteristics of one degree of freedom. That is, it is considered that at the time of collision due to play, the collided body causes the deformation accompanied by triangular hystersis elastically and plastically, and the spring characteristics of restitution force change piecewise by the collision. The exact solution using series solution and the approximate solution are performed, and the effectiveness of these theoretical solutions is confirmed by comparing with the solution using an analog computer. The relation between the accuracy of two analysis methods and nonlinear parameters is shown by the examples of numerical calculation. (Kako, I.)

Symmetric vectors and algebraic classification

International Nuclear Information System (INIS)

Leibowitz, E.

1980-01-01

The concept of symmetric vector field in Riemannian manifolds, which arises in the study of relativistic cosmological models, is analyzed. Symmetric vectors are tied up with the algebraic properties of the manifold curvature. A procedure for generating a congruence of symmetric fields out of a given pair is outlined. The case of a three-dimensional manifold of constant curvature (''isotropic universe'') is studied in detail, with all its symmetric vector fields being explicitly constructed

PT-symmetric ladders with a scattering core

Energy Technology Data Exchange (ETDEWEB)

D' Ambroise, J. [Department of Mathematics, Amherst College, Amherst, MA 01002-5000 (United States); Lepri, S. [CNR – Consiglio Nazionale delle Ricerche, Istituto dei Sistemi Complessi, via Madonna del piano 10, I-50019 Sesto Fiorentino (Italy); Istituto Nazionale di Fisica Nucleare, Sezione di Firenze, via G. Sansone 1, I-50019 Sesto Fiorentino (Italy); Malomed, B.A. [Department of Physical Electronics, School of Electrical Engineering, Faculty of Engineering, Tel Aviv University, Tel Aviv 69978 (Israel); Kevrekidis, P.G. [Department of Mathematics and Statistics, University of Massachusetts, Amherst, MA 01003-9305 (United States)

2014-08-01

We consider a PT-symmetric chain (ladder-shaped) system governed by the discrete nonlinear Schrödinger equation where the cubic nonlinearity is carried solely by two central “rungs” of the ladder. Two branches of scattering solutions for incident plane waves are found. We systematically construct these solutions, analyze their stability, and discuss non-reciprocity of the transmission associated with them. To relate the results to finite-size wavepacket dynamics, we also perform direct simulations of the evolution of the wavepackets, which confirm that the transmission is indeed asymmetric in this nonlinear system with the mutually balanced gain and loss. - Highlights: • We model a PT-symmetric ladder system with cubic nonlinearity on two central rungs. • We examine non-reciprocity and stability of incident plane waves. • Simulations of wavepackets confirm our results.

On the pseudo-norm in some PT-symmetric potentials

International Nuclear Information System (INIS)

Levai, G.

2005-01-01

Complete text of publication follows. PT-symmetric quantum mechanical systems possess non-hermitian Hamiltonian, still they have some characteristics similar to hermitian problems. The most notable of these is their discrete energy spectrum, which can be partly or completely real. These systems are invariant under the simultaneous action of the P space and T time inversion operations. Perhaps the simplest PT-symmetric Hamiltonian contains a one-dimensional Schroedinger operator with a complex potential satisfying the V*(-x) = V (x) relation. Another typical feature PT-symmetric systems have in common with hermitian problems is that their basis states form an orthogonal set provided that the inner product is redefined as (ψ φ)PT ≡ (ψ Pφ). However, the norm defined by this inner product, the pseudo-norm turned out to possess indefinite sign, and this raised the question of the probabilistic interpretation of PT-symmetric systems. This problem was later put into a more general context when it was found that PT symmetry is a special case of pseudo-hermiticity, and this explains most of the peculiar features of PT-symmetric systems. There have been several attempts to link PT-symmetric, and in general, pseudo- hermitian systems with equivalent hermitian ones, and the sign of the pseudo-norm was found to play an important role in this respect. It is thus essential to evaluate the pseudo- norm for various potentials, especially considering the fact that there are some inconsistencies in the available results. Numerical studies indicated that the sign of the pseudo-norm typically alternates according to the n principal quantum number as (-1) n , and this was later proven for a class of potentials that are written in a polynomial form of ix. However, some potentials of other type did not fit into this line: this was the case for the Scarf II potential, the most well-known exactly solvable PT-symmetric potential. In contrast with the other examples, this potential is

Representations of locally symmetric spaces

International Nuclear Information System (INIS)

Rahman, M.S.

1995-09-01

Locally symmetric spaces in reference to globally and Hermitian symmetric Riemannian spaces are studied. Some relations between locally and globally symmetric spaces are exhibited. A lucid account of results on relevant spaces, motivated by fundamental problems, are formulated as theorems and propositions. (author). 10 refs

Nuclear fusion rate of the muonic T3 molecule

International Nuclear Information System (INIS)

Faghihi, F.; Eskandari, M. R.

2004-01-01

The ground state binding energy, size and effective nuclear charge of the muonic T 3 molecule are calculated using Born-Oppenheimer adiabatic approximation. The system possesses two minimum positions, one at typically muonic and the second at the atomic distances. A symmetric planar vibrational model between two minima is assumed and the approximated potential are calculated. Moreover, nuclear fusion rate calculations of the short-life molecule is carried out due to the overlap integral of the resonance nuclear compound nucleus and the molecular wave functions

Hardware Realization of Chaos Based Symmetric Image Encryption

KAUST Repository

Barakat, Mohamed L.

2012-01-01

This thesis presents a novel work on hardware realization of symmetric image encryption utilizing chaos based continuous systems as pseudo random number generators. Digital implementation of chaotic systems results in serious degradations

Emerging nuclear energy systems and nuclear weapon proliferation

International Nuclear Information System (INIS)

Gsponer, A.; Sahin, S.; Jasani, B.

1983-01-01

Generally when considering problems of proliferation of nuclear weapons, discussions are focused on horizontal proliferation. However, the emerging nuclear energy systems currently have an impact mainly on vertical proliferation. The paper indicates that technologies connected with emerging nuclear energy systems, such as fusion reactors and accelerators, enhance the knowledge of thermonuclear weapon physics and will enable production of military useful nuclear materials (including some rare elements). At present such technologies are enhancing the arsenal of the nuclear weapon states. But one should not forget the future implications for horizontal proliferation of nuclear weapons as some of the techniques will in the near future be within the technological and economic capabilities of non-nuclear weapon states. Some of these systems are not under any international control. (orig.) [de

All-optical symmetric ternary logic gate

Science.gov (United States)

Chattopadhyay, Tanay

2010-09-01

Symmetric ternary number (radix=3) has three logical states (1¯, 0, 1). It is very much useful in carry free arithmetical operation. Beside this, the logical operation using this type of number system is also effective in high speed computation and communication in multi-valued logic. In this literature all-optical circuits for three basic symmetrical ternary logical operations (inversion, MIN and MAX) are proposed and described. Numerical simulation verifies the theoretical model. In this present scheme the different ternary logical states are represented by different polarized state of light. Terahertz optical asymmetric demultiplexer (TOAD) based interferometric switch has been used categorically in this manuscript.

Nuclear Fusion Rate Study of a Muonic Molecule via Nuclear Threshold Resonances

Science.gov (United States)

Faghihi, F.; Eskandari, M. R.

This work follows our previous calculations of the ground state binding energy, size, and the effective nuclear charge of the muonic T3 molecule, using the Born-Oppenheimer adiabatic approximation. In our past articles, we showed that the system possesses two minimum positions, the first one at the muonic distance and the second at the atomic distance. Also, the symmetric planner vibrational model assumed between the two minima and the approximated potential were calculated. Following from the previous studies, we now calculate the fusion rate of the T3 muonic molecule according to the overlap integral of the resonance nuclear compound nucleus and the molecular wave functions.

Symmetric imaging findings in neuroradiology

International Nuclear Information System (INIS)

Zlatareva, D.

2015-01-01

Full text: Learning objectives: to make a list of diseases and syndromes which manifest as bilateral symmetric findings on computed tomography and magnetic resonance imaging; to discuss the clinical and radiological differential diagnosis for these diseases; to explain which of these conditions necessitates urgent therapy and when additional studies and laboratory can precise diagnosis. There is symmetry in human body and quite often we compare the affected side to the normal one but in neuroradiology we might have bilateral findings which affected pair structures or corresponding anatomic areas. It is very rare when clinical data prompt diagnosis. Usually clinicians suspect such an involvement but Ct and MRI can reveal symmetric changes and are one of the leading diagnostic tool. The most common location of bilateral findings is basal ganglia and thalamus. There are a number of diseases affecting these structures symmetrically: metabolic and systemic diseases, intoxication, neurodegeneration and vascular conditions, toxoplasmosis, tumors and some infections. Malformations of cortical development and especially bilateral perisylvian polymicrogyria requires not only exact report on the most affected parts but in some cases genetic tests or combination with other clinical symptoms. In the case of herpes simplex encephalitis bilateral temporal involvement is common and this finding very often prompt therapy even before laboratory results. Posterior reversible encephalopathy syndrome (PReS) and some forms of hypoxic ischemic encephalopathy can lead to symmetric changes. In these acute conditions MR plays a crucial role not only in diagnosis but also in monitoring of the therapeutic effect. Patients with neurofibromatosis type 1 or type 2 can demonstrate bilateral optic glioma combined with spinal neurofibroma and bilateral acoustic schwanoma respectively. Mirror-image aneurysm affecting both internal carotid or middle cerebral arteries is an example of symmetry in

Global properties of locally rotational symmetric Bianchi I spacetimes in the Einstein-Yang-Mills-dilaton system

Energy Technology Data Exchange (ETDEWEB)

Narita, Makoto [Department of Mathematics, National Taiwan University, 1, Sec. 4, Roosevelt Rd., Taipei 106, Taiwan (China)

2006-12-21

We discuss the strong cosmic censorship conjecture for cosmological spacetimes in the Einstein-Yang-Mills-dilaton system. Locally rotational symmetric Bianchi I spacetimes are considered. We show local and global existence theorems for the system. Asymptotic behaviour for the spacetimes is also investigated. The curvature invariant is blowup at the initial singularities and the spacetimes are future geodesic complete. Thus, the strong cosmic censorship conjecture for the spacetimes holds.

Global properties of locally rotational symmetric Bianchi I spacetimes in the Einstein-Yang-Mills-dilaton system

International Nuclear Information System (INIS)

Narita, Makoto

2006-01-01

We discuss the strong cosmic censorship conjecture for cosmological spacetimes in the Einstein-Yang-Mills-dilaton system. Locally rotational symmetric Bianchi I spacetimes are considered. We show local and global existence theorems for the system. Asymptotic behaviour for the spacetimes is also investigated. The curvature invariant is blowup at the initial singularities and the spacetimes are future geodesic complete. Thus, the strong cosmic censorship conjecture for the spacetimes holds

Dual formulation of covariant nonlinear duality-symmetric action of kappa-symmetric D3-brane

Science.gov (United States)

Vanichchapongjaroen, Pichet

2018-02-01

We study the construction of covariant nonlinear duality-symmetric actions in dual formulation. Essentially, the construction is the PST-covariantisation and nonlinearisation of Zwanziger action. The covariantisation made use of three auxiliary scalar fields. Apart from these, the construction proceed in a similar way to that of the standard formulation. For example, the theories can be extended to include interactions with external fields, and that the theories possess two local PST symmetries. We then explicitly demonstrate the construction of covariant nonlinear duality-symmetric actions in dual formulation of DBI theory, and D3-brane. For each of these theories, the twisted selfduality condition obtained from duality-symmetric actions are explicitly shown to match with the duality relation between field strength and its dual from the one-potential actions. Their on-shell actions between the duality-symmetric and the one-potential versions are also shown to match. We also explicitly prove kappa-symmetry of the covariant nonlinear duality-symmetric D3-brane action in dual formulation.

Asymptotic properties of solvable PT-symmetric potentials

International Nuclear Information System (INIS)

Levai, G.

2010-01-01

Compete text of publication follows. The introduction of PT-symmetric quantum mechanics generated renewed interest in non-hermitian quantum mechanical systems in the past decade. PT symmetry means the invariance of a Hamiltonian under the simultaneous P space and T time reflection, the latter understood as complex conjugation. Considering the Schroedinger equation in one dimension, this corresponds to a potential with even real and odd imaginary components. This implies a delicate balance of emissive and absorptive regions that eventually manifests itself in properties that typically characterize real potentials, i.e. hermitian systems. These include partly or fully real energy spectrum and conserved (pseudo-)norm. A particularly notable feature of these systems is the spontaneous breakdown of PT symmetry, which typically occurs when the magnitude of the imaginary potential component exceeds a certain limit. At this point the real energy eigenvalues begin to merge pairwise and re-emerge as complex conjugate pairs. Another unusual property of PT-symmetric potentials is that they can, or sometimes have to be defined off the real x axis on trajectories that are symmetric with respect to the imaginary x axis. After more than a decade of theoretical investigations a remarkable recent development was the experimental verification of the existence of PT-symmetric systems in nature and the occurrence of spontaneous PT symmetry breaking in them. The experimental setup was a waveguide containing regions where loss and gain of flux occurred in a set out prescribed by PT symmetry. These experimental developments require the study of PT -symmetric potentials with various asymptotics, in which, furthermore, the complex potential component is finite in its range and/or its magnitude. Having in mind that PT symmetry allows for a wider variety of asymptotic properties than hermeticity, we studied three exactly solvable PT-symmetric potentials and compared their scattering and bound

Symmetric Tensor Decomposition

DEFF Research Database (Denmark)

Brachat, Jerome; Comon, Pierre; Mourrain, Bernard

2010-01-01

We present an algorithm for decomposing a symmetric tensor, of dimension n and order d, as a sum of rank-1 symmetric tensors, extending the algorithm of Sylvester devised in 1886 for binary forms. We recall the correspondence between the decomposition of a homogeneous polynomial in n variables...... of polynomial equations of small degree in non-generic cases. We propose a new algorithm for symmetric tensor decomposition, based on this characterization and on linear algebra computations with Hankel matrices. The impact of this contribution is two-fold. First it permits an efficient computation...... of the decomposition of any tensor of sub-generic rank, as opposed to widely used iterative algorithms with unproved global convergence (e.g. Alternate Least Squares or gradient descents). Second, it gives tools for understanding uniqueness conditions and for detecting the rank....

Nuclear spin relaxation by translational diffusion in solids

International Nuclear Information System (INIS)

Barton, W.A.; Sholl, C.A.

1978-01-01

The theory of nuclear spin relaxation by translational diffusion in solids developed in previous papers is applied to two-spin systems and third-nearest-neighbour jump models in FCC crystals. The two-spin systems describe the dipole-dipole interactions between stationary host spins and spins migrating amongst either the tetrahedral or the octahedral interstitial sites. The tetrahedral sites in a FCC crystal form a SC lattice and two models, the symmetric and asymmetric jump models, are considered for third-nearest-neighbour jumps on this lattice. Numerical results for the correlation function relevant for single crystals and polycrystals are presented over the entire temperature range. It is found that the simpler, but unphysical, symmetric jump model is a good approximation to the more complicated asymmetric jump model. (author)

Confining but chirally symmetric dense and cold matter

International Nuclear Information System (INIS)

Glozman, L. Ya.

2012-01-01

The possibility for existence of cold, dense chirally symmetric matter with confinement is reviewed. The answer to this question crucially depends on the mechanism of mass generation in QCD and interconnection of confinement and chiral symmetry breaking. This question can be clarified from spectroscopy of hadrons and their axial properties. Almost systematical parity doubling of highly excited hadrons suggests that their mass is not related to chiral symmetry breaking in the vacuum and is approximately chirally symmetric. Then there is a possibility for existence of confining but chirally symmetric matter. We clarify a possible mechanism underlying such a phase at low temperatures and large density. Namely, at large density the Pauli blocking prevents the gap equation to generate a solution with broken chiral symmetry. However, the chirally symmetric part of the quark Green function as well as all color non-singlet quantities are still infrared divergent, meaning that the system is with confinement. A possible phase transition to such a matter is most probably of the first order. This is because there are no chiral partners to the lowest lying hadrons.

A symmetric positive definite formulation for monolithic fluid structure interaction

KAUST Repository

Robinson-Mosher, Avi; Schroeder, Craig; Fedkiw, Ronald

2011-01-01

In this paper we consider a strongly coupled (monolithic) fluid structure interaction framework for incompressible flow, as opposed to a loosely coupled (partitioned) method. This requires solving a single linear system that combines the unknown velocities of the structure with the unknown pressures of the fluid. In our previous work, we were able to obtain a symmetric formulation of this coupled system; however, it was also indefinite, making it more difficult to solve. In fact in practice there have been cases where we have been unable to invert the system. In this paper we take a novel approach that consists of factoring the damping matrix of deformable structures and show that this can be used to obtain a symmetric positive definite system, at least to the extent that the uncoupled systems were symmetric positive definite. We use a traditional MAC grid discretization of the fluid and a fully Lagrangian discretization of the structures for the sake of exposition, noting that our procedure can be generalized to other scenarios. For the special case of rigid bodies, where there are no internal damping forces, we exactly recover the system of Batty et al. (2007) [4]. © 2010 Elsevier Inc.

A symmetric positive definite formulation for monolithic fluid structure interaction

KAUST Repository

Robinson-Mosher, Avi

2011-02-01

In this paper we consider a strongly coupled (monolithic) fluid structure interaction framework for incompressible flow, as opposed to a loosely coupled (partitioned) method. This requires solving a single linear system that combines the unknown velocities of the structure with the unknown pressures of the fluid. In our previous work, we were able to obtain a symmetric formulation of this coupled system; however, it was also indefinite, making it more difficult to solve. In fact in practice there have been cases where we have been unable to invert the system. In this paper we take a novel approach that consists of factoring the damping matrix of deformable structures and show that this can be used to obtain a symmetric positive definite system, at least to the extent that the uncoupled systems were symmetric positive definite. We use a traditional MAC grid discretization of the fluid and a fully Lagrangian discretization of the structures for the sake of exposition, noting that our procedure can be generalized to other scenarios. For the special case of rigid bodies, where there are no internal damping forces, we exactly recover the system of Batty et al. (2007) [4]. © 2010 Elsevier Inc.

Comparison of methods for uncertainty analysis of nuclear-power-plant safety-system fault-tree models

International Nuclear Information System (INIS)

Martz, H.F.; Beckman, R.J.; Campbell, K.; Whiteman, D.E.; Booker, J.M.

1983-04-01

A comparative evaluation is made of several methods for propagating uncertainties in actual coupled nuclear power plant safety system faults tree models. The methods considered are Monte Carlo simulation, the method of moments, a discrete distribution method, and a bootstrap method. The Monte Carlo method is found to be superior. The sensitivity of the system unavailability distribution to the choice of basic event unavailability distribution is also investigated. The system distribution is also investigated. The system distribution is especially sensitive to the choice of symmetric versus asymmetric basic event distributions. A quick-and dirty method for estimating percentiles of the system unavailability distribution is developed. The method identifies the appropriate basic event distribution percentiles that should be used in evaluating the Boolean system equivalent expression for a given fault tree model to arrive directly at the 5th, 10th, 50th, 90th, and 95th percentiles of the system unavailability distribution

Nuclear fuel cycle system analysis

International Nuclear Information System (INIS)

Ko, W. I.; Kwon, E. H.; Kim, S. G.; Park, B. H.; Song, K. C.; Song, D. Y.; Lee, H. H.; Chang, H. L.; Jeong, C. J.

2012-04-01

The nuclear fuel cycle system analysis method has been designed and established for an integrated nuclear fuel cycle system assessment by analyzing various methodologies. The economics, PR(Proliferation Resistance) and environmental impact evaluation of the fuel cycle system were performed using improved DB, and finally the best fuel cycle option which is applicable in Korea was derived. In addition, this research is helped to increase the national credibility and transparency for PR with developing and fulfilling PR enhancement program. The detailed contents of the work are as follows: 1)Establish and improve the DB for nuclear fuel cycle system analysis 2)Development of the analysis model for nuclear fuel cycle 3)Preliminary study for nuclear fuel cycle analysis 4)Development of overall evaluation model of nuclear fuel cycle system 5)Overall evaluation of nuclear fuel cycle system 6)Evaluate the PR for nuclear fuel cycle system and derive the enhancement method 7)Derive and fulfill of nuclear transparency enhancement method The optimum fuel cycle option which is economical and applicable to domestic situation was derived in this research. It would be a basis for establishment of the long-term strategy for nuclear fuel cycle. This work contributes for guaranteeing the technical, economical validity of the optimal fuel cycle option. Deriving and fulfillment of the method for enhancing nuclear transparency will also contribute to renewing the ROK-U.S Atomic Energy Agreement in 2014

Gravitational collapse and topology change in spherically symmetric dynamical systems

Energy Technology Data Exchange (ETDEWEB)

Csizmadia, Peter; Racz, Istvan, E-mail: cspeter@rmki.kfki.h, E-mail: iracz@rmki.kfki.h [RMKI H-1121 Budapest, Konkoly Thege Miklos ut 29-33 (Hungary)

2010-01-07

A new numerical framework, based on the use of a simple first-order strongly hyperbolic evolution equations, is introduced and tested in the case of four-dimensional spherically symmetric gravitating systems. The analytic setup is chosen such that our numerical method is capable of following the time evolution even after the appearance of trapped surfaces, more importantly, until the true physical singularities are reached. Using this framework, the gravitational collapse of various gravity-matter systems is investigated, with particular attention to the evolution in trapped regions. It is verified that, in advance of the formation of these curvature singularities, trapped regions develop in all cases, thereby supporting the validity of the weak cosmic censor hypothesis of Penrose. Various upper bounds on the rate of blow-up of the Ricci and Kretschmann scalars and the Misner-Sharp mass are provided. In spite of the unboundedness of the Ricci scalar, the Einstein-Hilbert action was found to remain finite in all the investigated cases. In addition, important conceptual issues related to the phenomenon of topology changes are discussed.

The development of an algebraic multigrid algorithm for symmetric positive definite linear systems

Energy Technology Data Exchange (ETDEWEB)

Vanek, P.; Mandel, J.; Brezina, M. [Univ. of Colorado, Denver, CO (United States)

1996-12-31

An algebraic multigrid algorithm for symmetric, positive definite linear systems is developed based on the concept of prolongation by smoothed aggregation. Coarse levels are generated automatically. We present a set of requirements motivated heuristically by a convergence theory. The algorithm then attempts to satisfy the requirements. Input to the method are the coefficient matrix and zero energy modes, which are determined from nodal coordinates and knowledge of the differential equation. Efficiency of the resulting algorithm is demonstrated by computational results on real world problems from solid elasticity, plate blending, and shells.

Nuclear material control systems for nuclear power plants

International Nuclear Information System (INIS)

1975-06-01

Paragraph 70.51(c) of 10 CFR Part 70 requires each licensee who is authorized to possess at any one time special nuclear material in a quantity exceeding one effective kilogram to establish, maintain, and follow written material control and accounting procedures that are sufficient to enable the licensee to account for the special nuclear material in his possession under license. While other paragraphs and sections of Part 70 provide specific requirements for nuclear material control systems for fuel cycle plants, such detailed requirements are not included for nuclear power reactors. This guide identifies elements acceptable to the NRC staff for a nuclear material control system for nuclear power reactors. (U.S.)

Symmetric minimally entangled typical thermal states for canonical and grand-canonical ensembles

Science.gov (United States)

Binder, Moritz; Barthel, Thomas

2017-05-01

Based on the density matrix renormalization group (DMRG), strongly correlated quantum many-body systems at finite temperatures can be simulated by sampling over a certain class of pure matrix product states (MPS) called minimally entangled typical thermal states (METTS). When a system features symmetries, these can be utilized to substantially reduce MPS computation costs. It is conceptually straightforward to simulate canonical ensembles using symmetric METTS. In practice, it is important to alternate between different symmetric collapse bases to decrease autocorrelations in the Markov chain of METTS. To this purpose, we introduce symmetric Fourier and Haar-random block bases that are efficiently mixing. We also show how grand-canonical ensembles can be simulated efficiently with symmetric METTS. We demonstrate these approaches for spin-1 /2 X X Z chains and discuss how the choice of the collapse bases influences autocorrelations as well as the distribution of measurement values and, hence, convergence speeds.

Symmetric eikonal expansion

International Nuclear Information System (INIS)

Matsuki, Takayuki

1976-01-01

Symmetric eikonal expansion for the scattering amplitude is formulated for nonrelativistic and relativistic potential scatterings and also for the quantum field theory. The first approximations coincide with those of Levy and Sucher. The obtained scattering amplitudes are time reversal invariant for all cases and are crossing symmetric for the quantum field theory in each order of approximation. The improved eikonal phase introduced by Levy and Sucher is also derived from the different approximation scheme from the above. (auth.)

On symmetric structures of order two

Directory of Open Access Journals (Sweden)

Michel Bousquet

2008-04-01

Full Text Available Let (ω n 0 < n be the sequence known as Integer Sequence A047749 http://www.research.att.com/ njas/sequences/A047749 In this paper, we show that the integer ω n enumerates various kinds of symmetric structures of order two. We first consider ternary trees having a reflexive symmetry and we relate all symmetric combinatorial objects by means of bijection. We then generalize the symmetric structures and correspondences to an infinite family of symmetric objects.

Dynamics of axial symmetric system in self-interacting Brans-Dicke gravity

International Nuclear Information System (INIS)

Sharif, M.; Manzoor, Rubab

2016-01-01

This paper investigates the dynamics of an axial reflection symmetric model in self-interacting Brans-Dicke gravity for anisotropic fluid. We formulate hydrodynamical equations and discuss oscillations using a time-dependent perturbation for both spin-dependent and spin-independent cases. The expressions of the frequency, the total energy density, and the equation of motion of the oscillating model are obtained. We study the instability of the oscillating models in weak approximations. It is found that the oscillations and stability of the model depend upon the dark energy source along with anisotropy and reflection effects. We conclude that the axial reflection system remains stable for stiffness parameter Γ = 1, collapses for Γ > 1, and becomes unstable for 0 < Γ < 1. (orig.)

Dynamics of axial symmetric system in self-interacting Brans-Dicke gravity

Energy Technology Data Exchange (ETDEWEB)

Sharif, M. [University of the Punjab, Department of Mathematics, Lahore (Pakistan); Manzoor, Rubab [University of Management and Technology, Department of Mathematics, Lahore (Pakistan)

2016-06-15

This paper investigates the dynamics of an axial reflection symmetric model in self-interacting Brans-Dicke gravity for anisotropic fluid. We formulate hydrodynamical equations and discuss oscillations using a time-dependent perturbation for both spin-dependent and spin-independent cases. The expressions of the frequency, the total energy density, and the equation of motion of the oscillating model are obtained. We study the instability of the oscillating models in weak approximations. It is found that the oscillations and stability of the model depend upon the dark energy source along with anisotropy and reflection effects. We conclude that the axial reflection system remains stable for stiffness parameter Γ = 1, collapses for Γ > 1, and becomes unstable for 0 < Γ < 1. (orig.)

The generalised Sylvester matrix equations over the generalised bisymmetric and skew-symmetric matrices

Science.gov (United States)

Dehghan, Mehdi; Hajarian, Masoud

2012-08-01

A matrix P is called a symmetric orthogonal if P = P T = P -1. A matrix X is said to be a generalised bisymmetric with respect to P if X = X T = PXP. It is obvious that any symmetric matrix is also a generalised bisymmetric matrix with respect to I (identity matrix). By extending the idea of the Jacobi and the Gauss-Seidel iterations, this article proposes two new iterative methods, respectively, for computing the generalised bisymmetric (containing symmetric solution as a special case) and skew-symmetric solutions of the generalised Sylvester matrix equation ? (including Sylvester and Lyapunov matrix equations as special cases) which is encountered in many systems and control applications. When the generalised Sylvester matrix equation has a unique generalised bisymmetric (skew-symmetric) solution, the first (second) iterative method converges to the generalised bisymmetric (skew-symmetric) solution of this matrix equation for any initial generalised bisymmetric (skew-symmetric) matrix. Finally, some numerical results are given to illustrate the effect of the theoretical results.

Efficient characterization of phase space mapping in axially symmetric optical systems

Science.gov (United States)

Barbero, Sergio; Portilla, Javier

2018-01-01

Phase space mapping, typically between an object and image plane, characterizes an optical system within a geometrical optics framework. We propose a novel conceptual frame to characterize the phase mapping in axially symmetric optical systems for arbitrary object locations, not restricted to a specific object plane. The idea is based on decomposing the phase mapping into a set of bivariate equations corresponding to different values of the radial coordinate on a specific object surface (most likely the entrance pupil). These equations are then approximated through bivariate Chebyshev interpolation at Chebyshev nodes, which guarantees uniform convergence. Additionally, we propose the use of a new concept (effective object phase space), defined as the set of points of the phase space at the first optical element (typically the entrance pupil) that are effectively mapped onto the image surface. The effective object phase space provides, by means of an inclusion test, a way to avoid tracing rays that do not reach the image surface.

Symmetrization of mathematical model of charge transport in semiconductors

Directory of Open Access Journals (Sweden)

Alexander M. Blokhin

2002-11-01

Full Text Available A mathematical model of charge transport in semiconductors is considered. The model is a quasilinear system of differential equations. A problem of finding an additional entropy conservation law and system symmetrization are solved.

A transformerless single-phase symmetrical Z-source HERIC inverter with reduced leakage currents for PV systems

DEFF Research Database (Denmark)

Li, Kerui; Shen, Yanfeng; Yang, Yongheng

2018-01-01

and thus low leakage currents in PV applications. The symmetric Z-source HERIC inverter requires two extra active switches. Nevertheless, the operation frequency of the two switches is the line frequency, leading to negligible losses. More importantly, the performance in terms of low leakage currents...... and harmonics is improved. Experimental tests are performed to validate the analysis and performance of the proposed system....

Canonical form of an elastoplastic model of nuclear fusion

International Nuclear Information System (INIS)

Mikhajlova, T.I.; Mikhajlov, I.N.; Do Dang, G.

1997-01-01

Starting from equations of motion describing the fusion process in symmetrical nuclear systems of low angular momenta we reconstruct the collective Lagrangian and dissipation Rayleigh functions. This opens new perspectives in studying the dynamical effects in the heavy nuclei collisions. In particular, it provides a basis for a quantal description of the fusion process and accompanying its effects

Various scattering properties of a new PT-symmetric non-Hermitian potential

International Nuclear Information System (INIS)

Ghatak, Ananya; Mandal, Raka Dona Ray; Mandal, Bhabani Prasad

2013-01-01

We complexify a 1-d potential V(x)=V 0 cosh 2 μ(tanh[(x−μd)/d]+tanh(μ)) 2 which exhibits bound, reflecting and free states to study various properties of a non-Hermitian system. This potential turns out a PT-symmetric non-Hermitian potential when one of the parameters (μ,d) becomes imaginary. For the case of μ→iμ, we have an entire real bound state spectrum. Explicit scattering states are constructed to show reciprocity at certain discrete values of energy even though the potential is not parity symmetric. Coexistence of deep energy minima of transmissivity with the multiple spectral singularities (MSS) is observed. We further show that this potential becomes invisible from the left (or right) at certain discrete energies. The penetrating states in the other case (d→id) are always reciprocal even though it is PT-invariant and no spectral singularity (SS) is present in this case. The presence of MSS and reflectionlessness is also discussed for the free states in the later case. -- Highlights: •Existence of multiple spectral singularities (MSS) in PT-symmetric non-Hermitian system is shown. •Reciprocity is restored at discrete positive energies even for parity non-invariant complex system. •Co-existence of MSS with deep energy minima of transitivity is obtained. •Possibilities of both unidirectional and bidirectional invisibility are explored for a non-Hermitian system. •Penetrating states are shown to be reciprocal for all energies for PT-symmetric system

Symmetric voltage-controlled variable resistance

Science.gov (United States)

Vanelli, J. C.

1978-01-01

Feedback network makes resistance of field-effect transistor (FET) same for current flowing in either direction. It combines control voltage with source and load voltages to give symmetric current/voltage characteristics. Since circuit produces same magnitude output voltage for current flowing in either direction, it introduces no offset in presense of altering polarity signals. It is therefore ideal for sensor and effector circuits in servocontrol systems.

Mesotherapy for benign symmetric lipomatosis.

Science.gov (United States)

Hasegawa, Toshio; Matsukura, Tomoyuki; Ikeda, Shigaku

2010-04-01

Benign symmetric lipomatosis, also known as Madelung disease, is a rare disorder characterized by fat distribution around the shoulders, arms, and neck in the context of chronic alcoholism. Complete excision of nonencapsulated lipomas is difficult. However, reports describing conservative therapeutic measures for lipomatosis are rare. The authors present the case of a 42-year-old man with a diagnosis of benign symmetric lipomatosis who had multiple, large, symmetrical masses in his neck. Multiple phosphatidylcholine injections in the neck were administered 4 weeks apart, a total of seven times to achieve lipolysis. The patient's lipomatosis improved in response to the injections, and he achieved good cosmetic results. Intralesional injection, termed mesotherapy, using phosphatidylcholine is a potentially effective therapy for benign symmetric lipomatosis that should be reconsidered as a therapeutic option for this disease.

Ultrastrong extraordinary transmission and reflection in PT-symmetric Thue-Morse optical waveguide networks.

Science.gov (United States)

Wu, Jiaye; Yang, Xiangbo

2017-10-30

In this paper, we construct a 1D PT-symmetric Thue-Morse aperiodic optical waveguide network (PTSTMAOWN) and mainly investigate the ultrastrong extraordinary transmission and reflection. We propose an approach to study the photonic modes and solve the problem of calculating photonic modes distributions in aperiodic networks due to the lack of dispersion functions and find that in a PTSTMAOWN there exist more photonic modes and more spontaneous PT-symmetric breaking points, which are quite different from other reported PT-symmetric optical systems. Additionally, we develop a method to sort spontaneous PT-symmetric breaking point zones to seek the strongest extraordinary point and obtain that at this point the strongest extraordinary transmission and reflection arrive at 2.96316 × 10 5 and 1.32761 × 10 5 , respectively, due to the PT-symmetric coupling resonance and the special symmetry pattern of TM networks. These enormous gains are several orders of magnitude larger than the previous results. This optical system may possess potential in designing optical amplifier, optical logic elements in photon computers and ultrasensitive optical switches with ultrahigh monochromatity.

Gradient coil system for nuclear magnetic resonance apparatus

International Nuclear Information System (INIS)

Frese, G.; Siebold, H.

1984-01-01

A gradient coil system for an image-generating, nuclear magnetic resonance tomographic apparatus, particularly a zeugmatographic apparatus. The gradient coil system is arranged on a support body of rotational symmetry, illustratively a hollow cylindrical support body, having an axis which extends along the z-direction of an x, y, z coordinate system which has an origin in the center of imaging region. The gradient coil system contains two pairs of toroidal individual coils which are arranged symmetrically with respect to an x-y plane which extends through the center of the imaging region and which are arranged perpendicular to the z-axis. The direction of current flow in the individual coils of a coil pair is opposite to the direction of flow in the individual coils of the other coil pair. Moreover, further sets of coils are provided for generating field gradient Gx in the x-direction, and Gy in the y-direction. The hollow cylindrical shape of the support body on which the individual coils are arranged permit an imaging region having a substantially spherical volume with a substantially constant field gradient Gz to be achieved. Each of the coils has a predetermined linkage factor which corresponds to the product of the current flowing through the number of coil turns of the coil. Those coils which are arranged further from the plane of symmetry have a substantially larger linkage factor than the coils which are nearer to the plane of symmetry

Charge-exchange QRPA with the Gogny Force for Axially-symmetric Deformed Nuclei

Energy Technology Data Exchange (ETDEWEB)

Martini, M., E-mail: martini.marco@gmail.com [Institut d' Astronomie et d' Astrophysique, Université Libre de Bruxelles, CP-226, 1050 Brussels (Belgium); CEA, DAM, DIF, F-91297 Arpajon (France); Goriely, S. [Institut d' Astronomie et d' Astrophysique, Université Libre de Bruxelles, CP-226, 1050 Brussels (Belgium); Péru, S. [CEA, DAM, DIF, F-91297 Arpajon (France)

2014-06-15

In recent years fully consistent quasiparticle random-phase approximation (QRPA) calculations using finite range Gogny force have been performed to study electromagnetic excitations of several axially-symmetric deformed nuclei up to the {sup 238}U. Here we present the extension of this approach to the charge-exchange nuclear excitations (pnQRPA). In particular we focus on the Isobaric Analog and Gamow-Teller resonances. A comparison of the predicted GT strength distribution with existing experimental data is presented. The role of nuclear deformation is shown. Special attention is paid to β-decay half-lives calculations for which experimental data exist and for specific isotone chains of relevance for the r-process nucleosynthesis.

Critical coupling and coherent perfect absorption for ranges of energies due to a complex gain and loss symmetric system

International Nuclear Information System (INIS)

Hasan, Mohammad; Ghatak, Ananya; Mandal, Bhabani Prasad

2014-01-01

We consider a non-Hermitian medium with a gain and loss symmetric, exponentially damped potential distribution to demonstrate different scattering features analytically. The condition for critical coupling (CC) for unidirectional wave and coherent perfect absorption (CPA) for bidirectional waves are obtained analytically for this system. The energy points at which total absorption occurs are shown to be the spectral singular points for the time reversed system. The possible energies at which CC occurs for left and right incidence are different. We further obtain periodic intervals with increasing periodicity of energy for CC and CPA to occur in this system. -- Highlights: •Energy ranges for CC and CPA are obtained explicitly for complex WS potential. •Analytical conditions for CC and CPA for PT symmetric WS potential are obtained. •Conditions for left and right CC are shown to be different. •Conditions for CC and CPA are shown to be that of SS for the time reversed system. •Our model shows the great flexibility of frequencies for CC and CPA

Hardware Realization of Chaos-based Symmetric Video Encryption

KAUST Repository

Ibrahim, Mohamad A.

2013-01-01

This thesis reports original work on hardware realization of symmetric video encryption using chaos-based continuous systems as pseudo-random number generators. The thesis also presents some of the serious degradations caused by digitally

Continuous symmetric reductions of the Adler-Bobenko-Suris equations

International Nuclear Information System (INIS)

Tsoubelis, D; Xenitidis, P

2009-01-01

Continuously symmetric solutions of the Adler-Bobenko-Suris class of discrete integrable equations are presented. Initially defined by their invariance under the action of both of the extended three-point generalized symmetries admitted by the corresponding equations, these solutions are shown to be determined by an integrable system of partial differential equations. The connection of this system to the Nijhoff-Hone-Joshi 'generating partial differential equations' is established and an auto-Baecklund transformation and a Lax pair for it are constructed. Applied to the H1 and Q1 δ=0 members of the Adler-Bobenko-Suris family, the method of continuously symmetric reductions yields explicit solutions determined by the Painleve trancendents

Gamma-ray tracking: Characterisation of the AGATA symmetric prototype detectors

International Nuclear Information System (INIS)

Boston, A.J.; Boston, H.C.; Cresswell, J.R.; Dimmock, M.R.; Nelson, L.; Nolan, P.J.; Rigby, S.; Lazarus, I.; Simpson, J.; Medina, P.; Santos, C.; Parisel, C.

2007-01-01

Each major technical advance in gamma-ray detection devices has resulted in significant new insights into the structure of atomic nuclei. The next major step in gamma-ray spectroscopy involves achieving the goal of a 4pi ball of Germanium detectors by using the technique of gamma-ray energy tracking in electrically segmented Germanium crystals. The resulting spectrometer will have an unparalleled level of detection power for nuclear electromagnetic radiation. Collaborations have been established in Europe (AGATA) [J. Simpson, Acta Phys. Pol. B 36 (2005) 1383. ] and the USA (GRETA/GRETINA) to build gamma-ray tracking spectrometers. This paper discusses the performance of the AGATA (Advanced Gamma Tracking Array) symmetric prototype detectors that have been tested at University of Liverpool. The use of a fully digital data acquisition system has allowed detector charge pulse shapes from a selection of well defined photon interaction positions to be analysed, yielding important information on the position sensitivity of the detector

Gamma-ray tracking: Characterisation of the AGATA symmetric prototype detectors

Energy Technology Data Exchange (ETDEWEB)

Boston, A.J. [Oliver Lodge Laboratory, University of Liverpool, Oxford Street, Liverpool L69 7ZE (United Kingdom)]. E-mail: ajboston@liv.ac.uk; Boston, H.C. [Oliver Lodge Laboratory, University of Liverpool, Oxford Street, Liverpool L69 7ZE (United Kingdom); Cresswell, J.R. [Oliver Lodge Laboratory, University of Liverpool, Oxford Street, Liverpool L69 7ZE (United Kingdom); Dimmock, M.R. [Oliver Lodge Laboratory, University of Liverpool, Oxford Street, Liverpool L69 7ZE (United Kingdom); Nelson, L. [Oliver Lodge Laboratory, University of Liverpool, Oxford Street, Liverpool L69 7ZE (United Kingdom); Nolan, P.J. [Oliver Lodge Laboratory, University of Liverpool, Oxford Street, Liverpool L69 7ZE (United Kingdom); Rigby, S. [Oliver Lodge Laboratory, University of Liverpool, Oxford Street, Liverpool L69 7ZE (United Kingdom); Lazarus, I. [STFC Daresbury Laboratory, Daresbury, Warrington WA4 4AD (United Kingdom); Simpson, J. [STFC Daresbury Laboratory, Daresbury, Warrington WA4 4AD (United Kingdom); Medina, P. [Institut de Recherches Subatomiques, Strasbourg BP28 67037 (France); Santos, C. [Institut de Recherches Subatomiques, Strasbourg BP28 67037 (France); Parisel, C. [Institut de Recherches Subatomiques, Strasbourg BP28 67037 (France)

2007-08-15

Each major technical advance in gamma-ray detection devices has resulted in significant new insights into the structure of atomic nuclei. The next major step in gamma-ray spectroscopy involves achieving the goal of a 4pi ball of Germanium detectors by using the technique of gamma-ray energy tracking in electrically segmented Germanium crystals. The resulting spectrometer will have an unparalleled level of detection power for nuclear electromagnetic radiation. Collaborations have been established in Europe (AGATA) [J. Simpson, Acta Phys. Pol. B 36 (2005) 1383. ] and the USA (GRETA/GRETINA) to build gamma-ray tracking spectrometers. This paper discusses the performance of the AGATA (Advanced Gamma Tracking Array) symmetric prototype detectors that have been tested at University of Liverpool. The use of a fully digital data acquisition system has allowed detector charge pulse shapes from a selection of well defined photon interaction positions to be analysed, yielding important information on the position sensitivity of the detector.

Various scattering properties of a new PT-symmetric non-Hermitian potential

Energy Technology Data Exchange (ETDEWEB)

Ghatak, Ananya, E-mail: gananya04@gmail.com [Department of Physics, Banaras Hindu University, Varanasi-221005 (India); Mandal, Raka Dona Ray, E-mail: rakad.ray@gmail.com [Department of Physics, Rajghat Besant School, Varanasi-221001 (India); Mandal, Bhabani Prasad, E-mail: bhabani.mandal@gmail.com [Department of Physics, Banaras Hindu University, Varanasi-221005 (India)

2013-09-15

We complexify a 1-d potential V(x)=V{sub 0}cosh{sup 2}μ(tanh[(x−μd)/d]+tanh(μ)){sup 2} which exhibits bound, reflecting and free states to study various properties of a non-Hermitian system. This potential turns out a PT-symmetric non-Hermitian potential when one of the parameters (μ,d) becomes imaginary. For the case of μ→iμ, we have an entire real bound state spectrum. Explicit scattering states are constructed to show reciprocity at certain discrete values of energy even though the potential is not parity symmetric. Coexistence of deep energy minima of transmissivity with the multiple spectral singularities (MSS) is observed. We further show that this potential becomes invisible from the left (or right) at certain discrete energies. The penetrating states in the other case (d→id) are always reciprocal even though it is PT-invariant and no spectral singularity (SS) is present in this case. The presence of MSS and reflectionlessness is also discussed for the free states in the later case. -- Highlights: •Existence of multiple spectral singularities (MSS) in PT-symmetric non-Hermitian system is shown. •Reciprocity is restored at discrete positive energies even for parity non-invariant complex system. •Co-existence of MSS with deep energy minima of transitivity is obtained. •Possibilities of both unidirectional and bidirectional invisibility are explored for a non-Hermitian system. •Penetrating states are shown to be reciprocal for all energies for PT-symmetric system.

PsiQuaSP-A library for efficient computation of symmetric open quantum systems.

Science.gov (United States)

Gegg, Michael; Richter, Marten

2017-11-24

In a recent publication we showed that permutation symmetry reduces the numerical complexity of Lindblad quantum master equations for identical multi-level systems from exponential to polynomial scaling. This is important for open system dynamics including realistic system bath interactions and dephasing in, for instance, the Dicke model, multi-Λ system setups etc. Here we present an object-oriented C++ library that allows to setup and solve arbitrary quantum optical Lindblad master equations, especially those that are permutationally symmetric in the multi-level systems. PsiQuaSP (Permutation symmetry for identical Quantum Systems Package) uses the PETSc package for sparse linear algebra methods and differential equations as basis. The aim of PsiQuaSP is to provide flexible, storage efficient and scalable code while being as user friendly as possible. It is easily applied to many quantum optical or quantum information systems with more than one multi-level system. We first review the basics of the permutation symmetry for multi-level systems in quantum master equations. The application of PsiQuaSP to quantum dynamical problems is illustrated with several typical, simple examples of open quantum optical systems.

Non-Existence of Black Hole Solutionsfor a Spherically Symmetric, Static Einstein-Dirac-Maxwell System

Science.gov (United States)

Finster, Felix; Smoller, Joel; Yau, Shing-Tung

We consider for j=1/2, 3/2,... a spherically symmetric, static system of (2j+1) Dirac particles, each having total angular momentum j. The Dirac particles interact via a classical gravitational and electromagnetic field. The Einstein-Dirac-Maxwell equations for this system are derived. It is shown that, under weak regularity conditions on the form of the horizon, the only black hole solutions of the EDM equations are the Reissner-Nordstrom solutions. In other words, the spinors must vanish identically. Applied to the gravitational collapse of a "cloud" of spin-1/2-particles to a black hole, our result indicates that the Dirac particles must eventually disappear inside the event horizon.

Nuclear power plant diagnostic system

International Nuclear Information System (INIS)

Prokop, K.; Volavy, J.

1982-01-01

Basic information is presented on diagnostic systems used at nuclear power plants with PWR reactors. They include systems used at the Novovoronezh nuclear power plant in the USSR, at the Nord power plant in the GDR, the system developed at the Hungarian VEIKI institute, the system used at the V-1 nuclear power plant at Jaslovske Bohunice in Czechoslovakia and systems of the Rockwell International company used in US nuclear power plants. These diagnostic systems are basically founded on monitoring vibrations and noise, loose parts, pressure pulsations, neutron noise, coolant leaks and acoustic emissions. The Rockwell International system represents a complex unit whose advantage is the on-line evaluation of signals which gives certain instructions for the given situation directly to the operator. The other described systems process signals using similar methods. Digitized signals only serve off-line computer analyses. (Z.M.)

Computer Code for Interpreting 13C NMR Relaxation Measurements with Specific Models of Molecular Motion: The Rigid Isotropic and Symmetric Top Rotor Models and the Flexible Symmetric Top Rotor Model

Science.gov (United States)

2017-01-01

top rotor superimposes an effective correlation time, τe, onto a symmetric top rotor to account for internal motion. 2. THEORY The purpose...specifically describe how simple 13C relaxation theory is used to describe quantitatively simple molecular 3 motions. More-detailed accounts ...of nuclear magnetic relaxation can be found in a number of basic textbooks (i.e., Farrar and Becker, 1971; Fukushima and Roeder, 1981; Harris, 1986

Holographic Spherically Symmetric Metrics

Science.gov (United States)

Petri, Michael

The holographic principle (HP) conjectures, that the maximum number of degrees of freedom of any realistic physical system is proportional to the system's boundary area. The HP has its roots in the study of black holes. It has recently been applied to cosmological solutions. In this article we apply the HP to spherically symmetric static space-times. We find that any regular spherically symmetric object saturating the HP is subject to tight constraints on the (interior) metric, energy-density, temperature and entropy-density. Whenever gravity can be described by a metric theory, gravity is macroscopically scale invariant and the laws of thermodynamics hold locally and globally, the (interior) metric of a regular holographic object is uniquely determined up to a constant factor and the interior matter-state must follow well defined scaling relations. When the metric theory of gravity is general relativity, the interior matter has an overall string equation of state (EOS) and a unique total energy-density. Thus the holographic metric derived in this article can serve as simple interior 4D realization of Mathur's string fuzzball proposal. Some properties of the holographic metric and its possible experimental verification are discussed. The geodesics of the holographic metric describe an isotropically expanding (or contracting) universe with a nearly homogeneous matter-distribution within the local Hubble volume. Due to the overall string EOS the active gravitational mass-density is zero, resulting in a coasting expansion with Ht = 1, which is compatible with the recent GRB-data.

Anti-symmetrized molecular dynamics: a new insight into the structure of nuclei

International Nuclear Information System (INIS)

Yoshiko, Kanada-En'yo; Masaaki, Kimura; Hisashi, Horiuchi

2003-01-01

The AMD (anti-symmetrized molecular dynamics) theory for nuclear structure is explained by showing its actual applications. First the formulation of AMD including various refined versions is briefly presented and its characteristics are discussed, putting a stress on its nature as an 'ab initio' theory. Then we demonstrate fruitful applications to various structure problems in stable nuclei, in order to explicitly verify the 'ab initio' nature of AMD, especially the ability to describe both mean-field-type structure and cluster structure. Finally, we show the results of applications of AMD to unstable nuclei, from which we see that AMD is powerful in elucidating and understanding various types of nuclear structure of unstable nuclei. (authors)

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.

An acceleration technique for the Gauss-Seidel method applied to symmetric linear systems

Directory of Open Access Journals (Sweden)

Jesús Cajigas

2014-06-01

Full Text Available A preconditioning technique to improve the convergence of the Gauss-Seidel method applied to symmetric linear systems while preserving symmetry is proposed. The preconditioner is of the form I + K and can be applied an arbitrary number of times. It is shown that under certain conditions the application of the preconditioner a finite number of steps reduces the matrix to a diagonal. A series of numerical experiments using matrices from spatial discretizations of partial differential equations demonstrates that both versions of the preconditioner, point and block version, exhibit lower iteration counts than its non-symmetric version. Resumen. Se propone una técnica de precondicionamiento para mejorar la convergencia del método Gauss-Seidel aplicado a sistemas lineales simétricos pero preservando simetría. El precondicionador es de la forma I + K y puede ser aplicado un número arbitrario de veces. Se demuestra que bajo ciertas condiciones la aplicación del precondicionador un número finito de pasos reduce la matriz del sistema precondicionado a una diagonal. Una serie de experimentos con matrices que provienen de la discretización de ecuaciones en derivadas parciales muestra que ambas versiones del precondicionador, por punto y por bloque, muestran un menor número de iteraciones en comparación con la versión que no preserva simetría.

On a kind of symmetric weakly non-linear ordinary differential systems

Czech Academy of Sciences Publication Activity Database

Fečkan, M.; Rontó, András; Dilna, N.

2016-01-01

Roč. 140, č. 2 (2016), s. 188-230 ISSN 0007-4497 Institutional support: RVO:67985840 Keywords : symmetric solution * symmetry * periodic solution Subject RIV: BA - General Mathematics Impact factor: 0.750, year: 2016 http://www.sciencedirect.com/science/article/pii/S0007449715000895

Solving the generalized symmetric eigenvalue problem using tile algorithms on multicore architectures

KAUST Repository

Ltaief, Hatem

2012-01-01

This paper proposes an efficient implementation of the generalized symmetric eigenvalue problem on multicore architecture. Based on a four-stage approach and tile algorithms, the original problem is first transformed into a standard symmetric eigenvalue problem by computing the Cholesky factorization of the right hand side symmetric definite positive matrix (first stage), and applying the inverse of the freshly computed triangular Cholesky factors to the original dense symmetric matrix of the problem (second stage). Calculating the eigenpairs of the resulting problem is then equivalent to the eigenpairs of the original problem. The computation proceeds by reducing the updated dense symmetric matrix to symmetric band form (third stage). The band structure is further reduced by applying a bulge chasing procedure, which annihilates the extra off-diagonal entries using orthogonal transformations (fourth stage). More details on the third and fourth stage can be found in Haidar et al. [Accepted at SC\\'11, November 2011]. The eigenvalues are then calculated from the tridiagonal form using the standard LAPACK QR algorithm (i.e., DTSEQR routine), while the complex and challenging eigenvector computations will be addressed in a companion paper. The tasks from the various stages can concurrently run in an out-of-order fashion. The data dependencies are cautiously tracked by the dynamic runtime system environment QUARK, which ensures the dependencies are not violated for numerical correctness purposes. The obtained tile four-stage generalized symmetric eigenvalue solver significantly outperforms the state-of-the-art numerical libraries (up to 21-fold speed up against multithreaded LAPACK with optimized multithreaded MKL BLAS and up to 4-fold speed up against the corresponding routine from the commercial numerical software Intel MKL) on four sockets twelve cores AMD system with a 24000×24000 matrix size. © 2012 The authors and IOS Press. All rights reserved.

Propagation of symmetric and anti-symmetric surface waves in aself-gravitating magnetized dusty plasma layer with generalized (r, q) distribution

Science.gov (United States)

Lee, Myoung-Jae; Jung, Young-Dae

2018-05-01

The dispersion properties of surface dust ion-acoustic waves in a self-gravitating magnetized dusty plasma layer with the (r, q) distribution are investigated. The result shows that the wave frequency of the symmetric mode in the plasma layer decreases with an increase in the wave number. It is also shown that the wave frequency of the symmetric mode decreases with an increase in the spectral index r. However, the wave frequency of the anti-symmetric mode increases with an increase in the wave number. It is also found that the anti-symmetric mode wave frequency increases with an increase in the spectral index r. In addition, it is found that the influence of the self-gravitation on the symmetric mode wave frequency decreases with increasing scaled Jeans frequency. Moreover, it is found that the wave frequency of the symmetric mode increases with an increase in the dust charge; however, the anti-symmetric mode shows opposite behavior.

Innovative nuclear energy systems roadmap

International Nuclear Information System (INIS)

2007-12-01

Developing nuclear energy that is sustainable, safe, has little waste by-product, and cannot be proliferated is an extremely vital and pressing issue. To resolve the four issues through free thinking and overall vision, research activities of 'innovative nuclear energy systems' and 'innovative separation and transmutation' started as a unique 21st Century COE Program for nuclear energy called the Innovative Nuclear Energy Systems for Sustainable Development of the World, COE-INES. 'Innovative nuclear energy systems' include research on CANDLE burn-up reactors, lead-cooled fast reactors and using nuclear energy in heat energy. 'Innovative separation and transmutation' include research on using chemical microchips to efficiently separate TRU waste to MA, burning or destroying waste products, or transmuting plutonium and other nuclear materials. Research on 'nuclear technology and society' and 'education' was also added in order for nuclear energy to be accepted into society. COE-INES was a five-year program ending in 2007. But some activities should be continued and this roadmap detailed them as a rough guide focusing inventions and discoveries. This technology roadmap was created for social acceptance and should be flexible to respond to changing times and conditions. (T. Tanaka)

Symmetric textures

International Nuclear Information System (INIS)

Ramond, P.

1993-01-01

The Wolfenstein parametrization is extended to the quark masses in the deep ultraviolet, and an algorithm to derive symmetric textures which are compatible with existing data is developed. It is found that there are only five such textures

A Derandomized Algorithm for RP-ADMM with Symmetric Gauss-Seidel Method

OpenAIRE

Xu, Jinchao; Xu, Kailai; Ye, Yinyu

2017-01-01

For multi-block alternating direction method of multipliers(ADMM), where the objective function can be decomposed into multiple block components, we show that with block symmetric Gauss-Seidel iteration, the algorithm will converge quickly. The method will apply a block symmetric Gauss-Seidel iteration in the primal update and a linear correction that can be derived in view of Richard iteration. We also establish the linear convergence rate for linear systems.

Nuclear steam supply system and method of installation

International Nuclear Information System (INIS)

Tower, S.N.; Christenson, J.A.; Braun, H.E.

1989-01-01

This patent describes a method of providing a nuclear reactor power plant at a predetermined use site accessible by predetermined navigable waterways. The method is practiced with apparatus including a nuclear reactor system. The system has a nuclear steam-supply section. The method consists of: constructing a nuclear reactor system at a manufacturing site remote from the predetermined use site but accessible to the predetermined waterways for transportation from the manufacturing site to the predetermined use site, the nuclear reactor system including a barge with the nuclear steam supply section constructed integrally with the barge. Simultaneously with the construction of the nuclear reactor system, constructing facilities at the use site to be integrated with the nuclear reactor system to form the nuclear-reactor power plant; transporting the nuclear reactor system along the waterways to the predetermined use site; at the use site joining the removal parts of the altered nuclear reactor system to the remainder of the altered nuclear reactor system to complete the nuclear reactor system; and installing the nuclear reactor system at the predetermined use site and integrating the nuclear reactor system to interact with the facilities constructed at the predetermined use site to form the nuclear-reactor power plant

Hyperons in nuclear matter from SU(3) chiral effective field theory

Energy Technology Data Exchange (ETDEWEB)

Petschauer, S.; Kaiser, N. [Technische Universitaet Muenchen, Physik Department, Garching (Germany); Haidenbauer, J. [Institut fuer Kernphysik, Forschungszentrum Juelich, Institute for Advanced Simulation, Juelich Center for Hadron Physics, Juelich (Germany); Meissner, Ulf G. [Institut fuer Kernphysik, Forschungszentrum Juelich, Institute for Advanced Simulation, Juelich Center for Hadron Physics, Juelich (Germany); Universitaet Bonn, Helmholtz-Institut fuer Strahlen- und Kernphysik and Bethe Center for Theoretical Physics, Bonn (Germany); Weise, W. [Technische Universitaet Muenchen, Physik Department, Garching (Germany); Villa Tambosi, ECT, Villazzano (Trento) (Italy)

2016-01-15

Brueckner theory is used to investigate the properties of hyperons in nuclear matter. The hyperon-nucleon interaction is taken from chiral effective field theory at next-to-leading order with SU(3) symmetric low-energy constants. Furthermore, the underlying nucleon-nucleon interaction is also derived within chiral effective field theory. We present the single-particle potentials of Λ and Σ hyperons in symmetric and asymmetric nuclear matter computed with the continuous choice for intermediate spectra. The results are in good agreement with the empirical information. In particular, our calculation gives a repulsive Σ-nuclear potential and a weak Λ-nuclear spin-orbit force. (orig.)

The discrete dynamics of symmetric competition in the plane.

Science.gov (United States)

Jiang, H; Rogers, T D

1987-01-01

We consider the generalized Lotka-Volterra two-species system xn + 1 = xn exp(r1(1 - xn) - s1yn) yn + 1 = yn exp(r2(1 - yn) - s2xn) originally proposed by R. M. May as a model for competitive interaction. In the symmetric case that r1 = r2 and s1 = s2, a region of ultimate confinement is found and the dynamics therein are described in some detail. The bifurcations of periodic points of low period are studied, and a cascade of period-doubling bifurcations is indicated. Within the confinement region, a parameter region is determined for the stable Hopf bifurcation of a pair of symmetrically placed period-two points, which imposes a second component of oscillation near the stable cycles. It is suggested that the symmetric competitive model contains much of the dynamical complexity to be expected in any discrete two-dimensional competitive model.

Majorana bound states in two-channel time-reversal-symmetric nanowire systems

DEFF Research Database (Denmark)

Gaidamauskas, Erikas; Paaske, Jens; Flensberg, Karsten

2014-01-01

We consider time-reversal-symmetric two-channel semiconducting quantum wires proximity coupled to a conventional s-wave superconductor. We analyze the requirements for a non-trivial topological phase, and find that necessary conditions are 1) the determinant of the pairing matrix in channel space...

Nuclear physics on a hypersphere

International Nuclear Information System (INIS)

Rho, M.

1989-01-01

This lecture covers three (related) topics: a hidden gauge symmetric (HGS) formulation of low-energy effective theories of the strong interaction, a modelling of dense nuclear matter by putting skyrmions (and instantons) on a hypersphere and a description in terms of skyrmions of the chiral phase transition at high nuclear matter density

Is the Universe matter-antimatter symmetric

International Nuclear Information System (INIS)

Alfven, H.

1976-09-01

According to the symmetric cosmology there should be antimatter regions in space which are equally as large as the matter regions. The regions of different kind are separated by Leidenfrost layers, which may be very thin and not observable from a distance. This view has met resistance which in part is based on the old view that the dilute interstellar and intergalactic medium is more or less homogeneous. However, through space research in the magnetosphere and interplanetary space we know that thin layers, dividing space into regions of different magnetisation, exist and based on this it is concluded that space in general has a cellular structure. This result may break down the psychological resistance to the symmetric theory. The possibility that every second star in our galaxy consists of antimatter is discussed, and it is shown that this view is not in conflict with any observations. As most stars are likely to be surrounded by solar systems of a structure like our own, it is concluded that collisions between comets and antistars (or anticomets and stars) would be rather frequent. Such collisions would result in phenomena of the same type as the observed cosmic γ-ray bursts. Another support for the symmetric cosmology is the continuous X-ray background radiation. Also many of the observed large energy releases in cosmos are likely to be due to annihilation

Probabilistic cloning of three symmetric states

International Nuclear Information System (INIS)

Jimenez, O.; Bergou, J.; Delgado, A.

2010-01-01

We study the probabilistic cloning of three symmetric states. These states are defined by a single complex quantity, the inner product among them. We show that three different probabilistic cloning machines are necessary to optimally clone all possible families of three symmetric states. We also show that the optimal cloning probability of generating M copies out of one original can be cast as the quotient between the success probability of unambiguously discriminating one and M copies of symmetric states.

Pretension construction of safety shell in Chashma nuclear power plant

International Nuclear Information System (INIS)

Gong Zhenbin; Li Yinong; Ni Shaowen

1999-01-01

19T16 post-tension grouped anchor system is applied to the safety shell pretension in Chashma Nuclear Power Plant. The stretching force of each bundle is about 3800 kN and the prestressed reinforcement is stretched in five stages. The double-control measurement of stress controlling and extension checking is applied in strict accordance with the principle of symmetrical construction

A symmetrical rail accelerator

International Nuclear Information System (INIS)

Igenbergs, E.

1991-01-01

This paper reports on the symmetrical rail accelerator that has four rails, which are arranged symmetrically around the bore. The opposite rails have the same polarity and the adjacent rails the opposite polarity. In this configuration the radial force acting upon the individual rails is significantly smaller than in a conventional 2-rail configuration and a plasma armature is focussed towards the axis of the barrel. Experimental results indicate a higher efficiency compared to a conventional rail accelerator

Fusion channel of pd charge - symmetric ion including photons

International Nuclear Information System (INIS)

Gheisari, R.

2007-01-01

The charge- symmetric pseudo nucleus pd is formed in the cascade processes in the muon catalyzed fusion. The nuclear fusion in pdμ ion can be considered in the photon field. For the spin states of pd (L=0) system, employing a new space wave function of three-body, the matrix element M1 proportional to S s∼ (πα 2 m p dω 3 )/[3(2S p d+1)m p 2 ]I 3 HeIM1Ipd ; 0 , S ∼ >I 2 (1) and the fusion rate λ Sp d γ =(S sp d/παm p d) ρ p dμ , ρ p dμ ∫I Ψ p dμ(R → = 0 , r → ) I 2 dr→ (2) for its ground state are calculated. The used wave function is introduced in the form of Ψ p dμ(r → , R → ) = Ρ (R){ξ dγ τ - 1/2 (γ , γ ' )xexp(-I γr → +γ ' R → I )+ξ dβ η - 1/2(β , β ' )xexp(-Iβr → + β ' R → I )}χ 0 ,0(R)Y 0 ,0. (3) The nuclear wave function χ 0 ,0(R)Y 0 ,0 is numerically calculated considering Wood-Saxon potential in the total Hamiltonian of the mentioned system. The good behavior of Ρ(R) is caused that our works are easily done in a short computation time. This function is linear from R =0 to 2.2x10 - 10 cm and then, is limited to 0.7068. The constant parameters of nuclear potential are obtained as well as those of the introduced wave function, when the boundary conditions are satisfied in our calculations. Notice that the notations (R → , r → ) are Jacobean coordinates. The radiative pd fusion rates for the two spin states in the pdμ mesic molecule are found to be λ 1 /2 γ 0.42μs - 1 and λ 3 / 2 γ = 0.13μs - 1, close to experimental data

Non-integrability of time-dependent spherically symmetric Yang-Mills equations

Energy Technology Data Exchange (ETDEWEB)

Matinyan, S G; Prokhorenko, E B; Savvidy, G K

1988-03-07

The integrability of time-dependent spherically symmetric Yang-Mills equations is studied using the Fermi-Pasta-Ulam method. It is shown that the motion of this system is ergodic, while the system itself is non-integrable, i.e. manifests dynamical chaos.

Reaction mechanism for the symmetric breakup of 24Mg following an interaction with 12C

International Nuclear Information System (INIS)

Gyapong, G.J.; Watson, D.L.; Catford, W.N.; Clarke, N.M.; Bennett, S.J.; Freer, M.; Fulton, B.R.; Jones, C.D.; Leddy, M.; Murgatroyd, J.T.; Rae, W.D.M.; Simmons, P.

1994-01-01

Data on the yield of the symmetric breakup of 24 Mg as a function of beam energy are presented and compared with detailed calculations of the energy dependence. The 24 Mg states seen in symmetric breakup agree with previously observed breakup states having spin and parities J π =4 + ,(6 + ),8 + . The data allow the variations of yield for indivual states to be judged, as the beam energy is varied. The variation in the yield of the 4 + states is compared in detail with calculations assuming several possible compound nuclear or direct reaction mechanisms. It is concluded that a massive ( 12 C) transfer or a simple statistical compound process are unlikely mechanisms, but that each of several other mechanisms is consistent with the data. ((orig.))

Mobile nuclear power systems

International Nuclear Information System (INIS)

Andersson, B.

1988-11-01

This report is meant to present a general survey of the mobile nuclear power systems and not a detailed review of their technical accomplishments. It is based in published material mainly up to 1987. Mobile nuclear power systems are of two fundamentally different kinds: nuclear reactors and isotopic generators. In the reactors the energy comes from nuclear fission and in the isotopic generators from the radioactive decay of suitable isotopes. The reactors are primarily used as power sourves on board nuclear submarines and other warships but have also been used in the space and in remote places. Their thermal power has ranged from 30 kWth (in a satellite) to 175 MWth (on board an aircraft carrier). Isotopic generators are suitable only for small power demands and have been used on board satellites and spaceprobes, automatic weatherstations, lighthouses and marine installations for navigation and observation. (author)

Nuclear imaging system

International Nuclear Information System (INIS)

Barrett, H.H.; Horrigan, F.A.

1975-01-01

This invention relates to a nuclear imaging system for mapping the source of high energy nuclear particles from a living organ which has selectively absorbed a radioactive compound by spatially coding the energy from the source in a Fresnel pattern on a detector and decoding the detector output to prouce an image of the source. The coding is produced by a Fresnel zone plate interposed between the nuclear energy source and the detector whose position is adjustable with respect to the detector to focus the slices of the nuclear source on the detector. By adjusting the zone plate to a plurality of positions, data from a plurality of cross-sectional slices are produced from which a three-dimensional image of the nuclear source may be obtained. (Patent Office Record)

Homotheties of cylindrically symmetric static spacetimes

International Nuclear Information System (INIS)

Qadir, A.; Ziad, M.; Sharif, M.

1998-08-01

In this note we consider the homotheties of cylindrically symmetric static spacetimes. We find that we can provide a complete list of all metrics that admit non-trivial homothetic motions and are cylindrically symmetric static. (author)

Future nuclear systems technology

International Nuclear Information System (INIS)

Brooks, H.

1979-01-01

Five directions can be identified for evolution of nuclear systems, possibly a sixth. These are, first, and perhaps most important, toward a means of extending fissile resources through improvement of the efficiency of their use; second, improvements in nuclear safety; third, reduction in the environmental impacts of nuclear electric power generation, particularly water requirements; fourth, improvements in proliferation resistance of the nuclear fuel cycle; and fifth, improvements in economics. And added in a sixth, and somewhat more speculative direction, the use of nuclear power for purposes other than the direct generation of electricity

Counting with symmetric functions

CERN Document Server

Mendes, Anthony

2015-01-01

This monograph provides a self-contained introduction to symmetric functions and their use in enumerative combinatorics.  It is the first book to explore many of the methods and results that the authors present. Numerous exercises are included throughout, along with full solutions, to illustrate concepts and also highlight many interesting mathematical ideas. The text begins by introducing fundamental combinatorial objects such as permutations and integer partitions, as well as generating functions.  Symmetric functions are considered in the next chapter, with a unique emphasis on the combinatorics of the transition matrices between bases of symmetric functions.  Chapter 3 uses this introductory material to describe how to find an assortment of generating functions for permutation statistics, and then these techniques are extended to find generating functions for a variety of objects in Chapter 4.  The next two chapters present the Robinson-Schensted-Knuth algorithm and a method for proving Pólya’s enu...

Nuclear containment systems and in-service inspection status of Korea nuclear power plants

Energy Technology Data Exchange (ETDEWEB)

Jihong, Park; Jaekeun, Hong; Banuk, Park [Korea Institute of Machinery and Materials, Dept. of Authorized Test and Evaluation, Kyungnam (Korea, Republic of)

2007-07-01

20 unit nuclear power plants in Korea have been operated and maintained since the first unit started in commercial service in 1978. Most recently 4 units were under construction and several units were planned to be constructed. by industries. 4 types of nuclear containment systems have been constructed until now: first, metal containments, then pre-stressed concrete containments with grouted tendon systems, followed by pre-stressed concrete containments with un-grouted tendon systems, and Korea standard nuclear containments. All the nuclear containments should be inspected periodically. Therefore for periodic in-service inspection, several appropriate technical requirements should be applied differently depending on the specific nuclear containment types. With the changes of times, nuclear containment systems have undergone a remarkable change, and finally nuclear containment system of Korea standard nuclear power plant was settled down, and as a matter of course it dominates the trend of present and future nuclear containment systems. Overall in-service inspection results of most Korea nuclear containments have not showed any serious evidence of degradation.

Symmetric approximations of the Navier-Stokes equations

International Nuclear Information System (INIS)

Kobel'kov, G M

2002-01-01

A new method for the symmetric approximation of the non-stationary Navier-Stokes equations by a Cauchy-Kovalevskaya-type system is proposed. Properties of the modified problem are studied. In particular, the convergence as ε→0 of the solutions of the modified problem to the solutions of the original problem on an infinite interval is established

Characteristic function-based semiparametric inference for skew-symmetric models

KAUST Repository

Potgieter, Cornelis J.

2012-12-26

Skew-symmetric models offer a very flexible class of distributions for modelling data. These distributions can also be viewed as selection models for the symmetric component of the specified skew-symmetric distribution. The estimation of the location and scale parameters corresponding to the symmetric component is considered here, with the symmetric component known. Emphasis is placed on using the empirical characteristic function to estimate these parameters. This is made possible by an invariance property of the skew-symmetric family of distributions, namely that even transformations of random variables that are skew-symmetric have a distribution only depending on the symmetric density. A distance metric between the real components of the empirical and true characteristic functions is minimized to obtain the estimators. The method is semiparametric, in that the symmetric component is specified, but the skewing function is assumed unknown. Furthermore, the methodology is extended to hypothesis testing. Two tests for a hypothesis of specific parameter values are considered, as well as a test for the hypothesis that the symmetric component has a specific parametric form. A resampling algorithm is described for practical implementation of these tests. The outcomes of various numerical experiments are presented. © 2012 Board of the Foundation of the Scandinavian Journal of Statistics.

Nuclear Systems Kilopower Overview

Science.gov (United States)

Palac, Don; Gibson, Marc; Mason, Lee; Houts, Michael; McClure, Patrick; Robinson, Ross

2016-01-01

The Nuclear Systems Kilopower Project was initiated by NASAs Space Technology Mission Directorate Game Changing Development Program in fiscal year 2015 to demonstrate subsystem-level technology readiness of small space fission power in a relevant environment (Technology Readiness Level 5) for space science and human exploration power needs. The Nuclear Systems Kilopower Project consists of two elements. The primary element is the Kilopower Prototype Test, also called the Kilopower Reactor Using Stirling Technology(KRUSTY) Test. This element consists of the development and testing of a fission ground technology demonstrator of a 1 kWe fission power system. A 1 kWe system matches requirements for some robotic precursor exploration systems and future potential deep space science missions, and also allows a nuclear ground technology demonstration in existing nuclear test facilities at low cost. The second element, the Mars Kilopower Scalability Study, consists of the analysis and design of a scaled-up version of the 1 kWe reference concept to 10 kWe for Mars surface power projected requirements, and validation of the applicability of the KRUSTY experiment to key technology challenges for a 10 kWe system. If successful, these two elements will lead to initiation of planning for a technology demonstration of a 10 kWe fission power capability for Mars surface outpost power.

21 CFR 892.1310 - Nuclear tomography system.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Nuclear tomography system. 892.1310 Section 892...) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1310 Nuclear tomography system. (a) Identification. A nuclear tomography system is a device intended to detect nuclear radiation in the body and...

Symmetric metamaterials based on flower-shaped structure

International Nuclear Information System (INIS)

Tuong, P.V.; Park, J.W.; Rhee, J.Y.; Kim, K.W.; Cheong, H.; Jang, W.H.; Lee, Y.P.

2013-01-01

We proposed new models of metamaterials (MMs) based on a flower-shaped structure (FSS), whose “meta-atoms” consist of two flower-shaped metallic parts separated by a dielectric layer. Like the non-symmetric MMs based on cut-wire-pairs or electric ring resonators, the symmetrical FSS demonstrates the negative permeability at GHz frequencies. Employing the results, we designed a symmetric negative-refractive-index MM [a symmetric combined structure (SCS)], which is composed of FSSs and cross continuous wires. The MM properties of the FSS and the SCS are presented numerically and experimentally. - Highlights: • A new designed of sub-wavelength metamaterial, flower-shaped structure was proposed. • Flower-shaped meta-atom illustrated effective negative permeability. • Based on the meta-atom, negative refractive index was conventionally gained. • Negative refractive index was demonstrated with symmetric properties for electromagnetic wave. • Dimensional parameters were studied under normal electromagnetic wave

PT -symmetric gain and loss in a rotating Bose-Einstein condensate

Science.gov (United States)

Haag, Daniel; Dast, Dennis; Cartarius, Holger; Wunner, Günter

2018-03-01

PT -symmetric quantum mechanics allows finding stationary states in mean-field systems with balanced gain and loss of particles. In this work we apply this method to rotating Bose-Einstein condensates with contact interaction which are known to support ground states with vortices. Due to the particle exchange with the environment transport phenomena through ultracold gases with vortices can be studied. We find that even strongly interacting rotating systems support stable PT -symmetric ground states, sustaining a current parallel and perpendicular to the vortex cores. The vortices move through the nonuniform particle density and leave or enter the condensate through its borders creating the required net current.

The symmetric = ω -semi-classical orthogonal polynomials of class one

Science.gov (United States)

Maroni, P.; Mejri, M.

2008-12-01

We give the system of Laguerre-Freud equations associated with the = ω -semi-classical functionals of class one, where = ω is the divided difference operator. This system is solved in the symmetric case. There are essentially two canonical cases. The corresponding integral representations are given.

Super-symmetric informationally complete measurements

Energy Technology Data Exchange (ETDEWEB)

Zhu, Huangjun, E-mail: hzhu@pitp.ca

2015-11-15

Symmetric informationally complete measurements (SICs in short) are highly symmetric structures in the Hilbert space. They possess many nice properties which render them an ideal candidate for fiducial measurements. The symmetry of SICs is intimately connected with the geometry of the quantum state space and also has profound implications for foundational studies. Here we explore those SICs that are most symmetric according to a natural criterion and show that all of them are covariant with respect to the Heisenberg–Weyl groups, which are characterized by the discrete analog of the canonical commutation relation. Moreover, their symmetry groups are subgroups of the Clifford groups. In particular, we prove that the SIC in dimension 2, the Hesse SIC in dimension 3, and the set of Hoggar lines in dimension 8 are the only three SICs up to unitary equivalence whose symmetry groups act transitively on pairs of SIC projectors. Our work not only provides valuable insight about SICs, Heisenberg–Weyl groups, and Clifford groups, but also offers a new approach and perspective for studying many other discrete symmetric structures behind finite state quantum mechanics, such as mutually unbiased bases and discrete Wigner functions.

Nuclear Space Power Systems Materials Requirements

International Nuclear Information System (INIS)

Buckman, R.W. Jr.

2004-01-01

High specific energy is required for space nuclear power systems. This generally means high operating temperatures and the only alloy class of materials available for construction of such systems are the refractory metals niobium, tantalum, molybdenum and tungsten. The refractory metals in the past have been the construction materials selected for nuclear space power systems. The objective of this paper will be to review the past history and requirements for space nuclear power systems from the early 1960's through the SP-100 program. Also presented will be the past and present status of refractory metal alloy technology and what will be needed to support the next advanced nuclear space power system. The next generation of advanced nuclear space power systems can benefit from the review of this past experience. Because of a decline in the refractory metal industry in the United States, ready availability of specific refractory metal alloys is limited

Nuclear data information system for nuclear materials

International Nuclear Information System (INIS)

Fujita, Mitsutane; Noda, Tetsuji; Utsumi, Misako

1996-01-01

The conceptual system for nuclear material design is considered and some trials on WWW server with functions of the easily accessible simulation of nuclear reactions are introduced. Moreover, as an example of the simulation on the system using nuclear data, transmutation calculation was made for candidate first wall materials such as 9Cr-2W steel, V-5Cr-5Ti and SiC in SUS316/Li 2 O/H 2 O(SUS), 9Cr-2W/Li 2 O/H 2 O(RAF), V alloy/Li/Be(V), and SiC/Li 2 ZrO 3 /He(SiC) blanket/shield systems based on ITER design model. Neutron spectrum varies with different blanket/shield compositions. The flux of low energy neutrons decreases in order of V< SiC< RAF< SUS blanket/shield systems. Fair amounts of W depletion in 9Cr-2W steel and the increase of Cr content in V-5Cr-5Ti were predicted in SUS or RAF systems. Concentration change in W and Cr is estimated to be suppressed if Li coolant is used in place of water. Helium and hydrogen production are not strongly affected by the different blanket/shield compositions. (author)

Oscillating molecular dipoles require strongly correlated electronic and nuclear motion

International Nuclear Information System (INIS)

Chang, Bo Y; Shin, Seokmin; Palacios, Alicia; Martín, Fernando; Sola, Ignacio R

2015-01-01

To create an oscillating electric dipole in an homonuclear diatomic cation without an oscillating driver one needs (i) to break the symmetry of the system and (ii) to sustain highly correlated electronic and nuclear motion. Based on numerical simulations in H 2 + we present results for two schemes. In the first one (i) is achieved by creating a superposition of symmetric and antisymmetric electronic states freely evolving, while (ii) fails. In a second scheme, by preparing the system in a dressed state of a strong static field, both conditions hold. We then analyze the robustness of this scheme with respect to features of the nuclear wave function and its intrinsic sources of decoherence. (tutorial)

Experience with Nuclear Medicine Information System

Directory of Open Access Journals (Sweden)

Bilge Volkan-Salanci

2012-12-01

Full Text Available Objective: Radiology information system (RIS is basically evolved for the need of radiologists and ignores the vital steps needed for a proper work flow of Nuclear Medicine Department. Moreover, CT/MRI oriented classical PACS systems are far from satisfying Nuclear Physicians like storing dynamic data for reprocessing and quantitative analysis of colored images. Our purpose was to develop a workflow based Nuclear Medicine Information System (NMIS that fulfills the needs of Nuclear Medicine Department and its integration to hospital PACS system. Material and Methods: Workflow in NMIS uses HL7 (health level seven and steps include, patient scheduling and retrieving information from HIS (hospital information system, radiopharmacy, acquisition, digital reporting and approval of the reports using Nuclear Medicine specific diagnostic codes. Images and dynamic data from cameras of are sent to and retrieved from PACS system (Corttex© for reprocessing and quantitative analysis. Results: NMIS has additional functions to the RIS such as radiopharmaceutical management program which includes stock recording of both radioactive and non-radioactive substances, calculation of the radiopharmaceutical dose for individual patient according to body weight and maximum permissible activity, and calculation of radioactivity left per unit volume for each radionuclide according their half lives. Patient scheduling and gamma camera patient work list settings were arranged according to specific Nuclear Medicine procedures. Nuclear Medicine images and reports can be retrieved and viewed from HIS. Conclusion: NMIS provides functionality to standard RIS and PACS system according to the needs of Nuclear Medicine. (MIRT 2012;21:97-102

Nuclear propulsion systems engineering

International Nuclear Information System (INIS)

Madsen, W.W.; Neuman, J.E.: Van Haaften, D.H.

1992-01-01

The Nuclear Energy for Rocket Vehicle Application (NERVA) program of the 1960's and early 1970's was dramatically successful, with no major failures during the entire testing program. This success was due in large part to the successful development of a systems engineering process. Systems engineering, properly implemented, involves all aspects of the system design and operation, and leads to optimization of theentire system: cost, schedule, performance, safety, reliability, function, requirements, etc. The process must be incorporated from the very first and continued to project completion. This paper will discuss major aspects of the NERVA systems engineering effort, and consider the implications for current nuclear propulsion efforts

Linac design algorithm with symmetric segments

International Nuclear Information System (INIS)

Takeda, Harunori; Young, L.M.; Nath, S.; Billen, J.H.; Stovall, J.E.

1996-01-01

The cell lengths in linacs of traditional design are typically graded as a function of particle velocity. By making groups of cells and individual cells symmetric in both the CCDTL AND CCL, the cavity design as well as mechanical design and fabrication is simplified without compromising the performance. We have implemented a design algorithm in the PARMILA code in which cells and multi-cavity segments are made symmetric, significantly reducing the number of unique components. Using the symmetric algorithm, a sample linac design was generated and its performance compared with a similar one of conventional design

Nuclear information access system

International Nuclear Information System (INIS)

Ham, C. H.; Yang, M. H.; Yoon, S. W.

1998-01-01

The energy supply in the countries, which have abundant energy resources, may not be affected by accepting the assertion of anti-nuclear and environment groups. Anti-nuclear movements in the countries which have little energy resources may cause serious problem in securing energy supply. Especially, it is distinct in Korea because she heavily depends on nuclear energy in electricity supply(nuclear share in total electricity supply is about 40%).The cause of social trouble surrounding nuclear energy is being involved with various circumstances. However, it is very important that we are not aware of the importance of information access and prepared for such a situation from the early stage of nuclear energy's development. In those matter, this paper analyzes the contents of nuclear information access system in France and Japan which have dynamic nuclear development program and presents the direction of the nuclear access regime through comparing Korean status and referring to progresses of the regime

PT symmetric Aubry–Andre model

International Nuclear Information System (INIS)

Yuce, C.

2014-01-01

PT symmetric Aubry–Andre model describes an array of N coupled optical waveguides with position-dependent gain and loss. We show that the reality of the spectrum depends sensitively on the degree of quasi-periodicity for small number of lattice sites. We obtain the Hofstadter butterfly spectrum and discuss the existence of the phase transition from extended to localized states. We show that rapidly changing periodical gain/loss materials almost conserve the total intensity. - Highlights: • We show that PT symmetric Aubry–Andre model may have real spectrum. • We show that the reality of the spectrum depends sensitively on the degree of disorder. • We obtain the Hofstadter butterfly spectrum for PT symmetric Aubry–Andre model. • We discuss that phase transition from extended to localized states exists

PT symmetric Aubry–Andre model

Energy Technology Data Exchange (ETDEWEB)

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

2014-06-13

PT symmetric Aubry–Andre model describes an array of N coupled optical waveguides with position-dependent gain and loss. We show that the reality of the spectrum depends sensitively on the degree of quasi-periodicity for small number of lattice sites. We obtain the Hofstadter butterfly spectrum and discuss the existence of the phase transition from extended to localized states. We show that rapidly changing periodical gain/loss materials almost conserve the total intensity. - Highlights: • We show that PT symmetric Aubry–Andre model may have real spectrum. • We show that the reality of the spectrum depends sensitively on the degree of disorder. • We obtain the Hofstadter butterfly spectrum for PT symmetric Aubry–Andre model. • We discuss that phase transition from extended to localized states exists.

Advanced nuclear systems. Review study

International Nuclear Information System (INIS)

Liebert, Wolfgang; Glaser, Alexander; Pistner, Christoph; Baehr, Roland; Hahn, Lothar

1999-04-01

The task of this review study is to from provide an overview of the developments in the field of the various advanced nuclear systems, and to create the basis for more comprehensive studies of technology assessment. In an overview the concepts for advanced nuclear systems pursued worldwide are subdivided into eight subgroups. A coarse examination raster (set pattern) is developed to enable a detailed examination of the selected systems. In addition to a focus on enhanced safety features, further aspects are also taken into consideration, like the lowering of the proliferation risk, the enhancement of the economic competitiveness of the facilities and new usage possibilities (for instance concerning the relaxation of the waste disposal problem or the usage of alternative fuels to uranium). The question about the expected time span for realization and the discussion about the obstacles on the way to a commercially usable reactor also play a substantial role as well as disposal requirements as far as they can be presently recognized. In the central chapter of this study, the documentation of the representatively selected concepts is evaluated as well as existing technology assessment studies and expert opinions. In a few cases where this appears to be necessary, according technical literature, further policy advisory reports, expert statements as well as other relevant sources are taken into account. Contradictions, different assessments and dissents in the literature as well as a few unsettled questions are thus indicated. The potential of advanced nuclear systems with respect to economical and societal as well as environmental objectives cannot exclusively be measured by the corresponding intrinsic or in comparison remarkable technical improvements. The acceptability of novel or improved systems in nuclear technology will have to be judged by their convincing solutions for the crucial questions of safety, nuclear waste and risk of proliferation of nuclear weapons

Comprehensive asynchronous symmetric rendezvous algorithm in ...

Indian Academy of Sciences (India)

Meenu Chawla

2017-11-10

Nov 10, 2017 ... Simulation results affirm that CASR algorithm performs better in terms of average time-to-rendezvous as compared ... process; neighbour discovery; symmetric rendezvous algorithm. 1. .... dezvous in finite time under the symmetric model. The CH ..... CASR algorithm in Matlab 7.11 and performed several.

Scenario-based roadmapping assessing nuclear technology development paths for future nuclear energy system scenarios

International Nuclear Information System (INIS)

Van Den Durpel, Luc; Roelofs, Ferry; Yacout, Abdellatif

2009-01-01

Nuclear energy may play a significant role in a future sustainable energy mix. The transition from today's nuclear energy system towards a future more sustainable nuclear energy system will be dictated by technology availability, energy market competitiveness and capability to achieve sustainability through the nuclear fuel cycle. Various scenarios have been investigated worldwide each with a diverse set of assumptions on the timing and characteristics of new nuclear energy systems. Scenario-based roadmapping combines the dynamic scenario-analysis of nuclear energy systems' futures with the technology roadmap information published and analysed in various technology assessment reports though integrated within the nuclear technology roadmap Nuclear-Roadmap.net. The advantages of this combination is to allow mutual improvement of scenario analysis and nuclear technology roadmapping providing a higher degree of confidence in the assessment of nuclear energy system futures. This paper provides a description of scenario-based roadmapping based on DANESS and Nuclear-Roadmap.net. (author)

Physical aspects of pseudo-Hermitian and PT-symmetric quantum mechanics

International Nuclear Information System (INIS)

Mostafazadeh, Ali; Batal, Ahmet

2004-01-01

For a non-Hermitian Hamiltonian H possessing a real spectrum, we introduce a canonical orthonormal basis in which a previously introduced unitary mapping of H to a Hermitian Hamiltonian h takes a simple form. We use this basis to construct the observables O α of the quantum mechanics based on H. In particular, we introduce pseudo-Hermitian position and momentum operators and a pseudo-Hermitian quantization scheme that relates the latter to the ordinary classical position and momentum observables. These allow us to address the problem of determining the conserved probability density and the underlying classical system for pseudo-Hermitian and in particular PT-symmetric quantum systems. As a concrete example we construct the Hermitian Hamiltonian h, the physical observables O α , the localized states and the conserved probability density for the non-Hermitian PT-symmetric square well. We achieve this by employing an appropriate perturbation scheme. For this system, we conduct a comprehensive study of both the kinematical and dynamical effects of the non-Hermiticity of the Hamiltonian on various physical quantities. In particular, we show that these effects are quantum mechanical in nature and diminish in the classical limit. Our results provide an objective assessment of the physical aspects of PT-symmetric quantum mechanics and clarify its relationship with both conventional quantum mechanics and classical mechanics

Symmetric Encryption Relying on Chaotic Henon System for Secure Hardware-Friendly Wireless Communication of Implantable Medical Systems

Directory of Open Access Journals (Sweden)

Taha Belkhouja

2018-05-01

Full Text Available Healthcare remote devices are recognized as a promising technology for treating health related issues. Among them are the wireless Implantable Medical Devices (IMDs: These electronic devices are manufactured to treat, monitor, support or replace defected vital organs while being implanted in the human body. Thus, they play a critical role in healing and even saving lives. Current IMDs research trends concentrate on their medical reliability. However, deploying wireless technology in such applications without considering security measures may offer adversaries an easy way to compromise them. With the aim to secure these devices, we explore a new scheme that creates symmetric encryption keys to encrypt the wireless communication portion. We will rely on chaotic systems to obtain a synchronized Pseudo-Random key. The latter will be generated separately in the system in such a way that avoids a wireless key exchange, thus protecting patients from the key theft. Once the key is defined, a simple encryption system that we propose in this paper will be used. We analyze the performance of this system from a cryptographic point of view to ensure that it offers a better safety and protection for patients.

For establishment on nuclear disaster prevention system

International Nuclear Information System (INIS)

Anon.

2000-01-01

For increasing requirement of peoples for review of nuclear disaster countermeasure at a chance of the JCO critical accident, the Japanese Government newly established the 'Special Measure Act on Nuclear Disaster Countermeasure', which was enacted on July 16, 2000. The nuclear business relatives such as electric power company and so forth established the Business program on nuclear disaster prevention in nuclear business relatives' after their consultation with local communities at their construction, under their co-operation. Simultaneously, the electric power industry field decided to intend to provide some sufficient countermeasures to incidental formation of nuclear accident such as start of the Co-operative agreement on nuclear disaster prevention among the nuclear business relatives' and so forth. Here were described on nuclear safety and disaster prevention, nuclear disaster prevention systems at the electric power industry field, abstract on 'Business program on nuclear disaster prevention in nuclear business relatives', preparation of technical assistance system for nuclear disaster prevention, executive methods and subjects on nuclear disaster prevention at construction areas, recent business on nuclear disaster prevention at the Nuclear Technical Center, and subjects on establishment of nuclear disaster prevention system. (G.K.)

Effects of Gogny type interactions on the nuclear flow

International Nuclear Information System (INIS)

Sebille, F.; De La Mota, V.; Jouault, B.; Schuck, P.

1995-01-01

A flow analysis on symmetric and asymmetric reactions from 100 to 400 MeV/n is performed in the framework of the semi-classical Landau-Vlasov approach. In this energy range our results present two different trends. At lower energies it is governed by the momentum dependence of the nuclear optical potential, whereas at higher energies its density dependence plays a crucial role leading to a rather pronounced sensitivity of the incompressibility modulus. The non-locality of the nuclear interaction is relevant for asymmetric colliding systems. With an incompressibility modulus in the vicinity of 200 MeV, an excellent quantitative description of the flow behavior with incident energy and impact parameter or the system mass is provided. (authors)., 26 refs., 6 figs., 3 tabs

The national nuclear material tracking system. A Korea's countermeasure against nuclear terrorism

International Nuclear Information System (INIS)

Moon, Joo Hyun

2011-01-01

Since nuclear terrorism has been identified as a real threat, the Korean government has earnestly developed elementary technologies and sub-systems for establishing an integrated defensive system against nuclear terrorism, which is based on the concept of defense-in-depth. This paper introduces the gist and implications of the studies that have been conducted in building the national nuclear material tracking system for preventing and intercepting the illicit trafficking and transporting of nuclear material in Korea. (orig.)

The double nuclear system is a new object of nuclear physics studies

International Nuclear Information System (INIS)

Volkov, V.V.

1980-01-01

Deep inelastic collisions of two complex nuclei result in formation of the specific nuclear complex - a double nuclear system which is a new unit of nuclear microworld. In this paper we consider the conditions under which the double nuclear system is formed, its properties, the statistical regularities of its disintegration, and the nuclear shell structure effect on its evolution. The possibility of using deep inelastic transfer reactions to produce nuclear far from the region of β-stability and nuclei with high angular momentum is discussed. (author)

The system of nuclear material control of Kazakhstan

International Nuclear Information System (INIS)

Yeligbayeva, G.Zh.

2001-01-01

Full text: The State system for nuclear material control consists of three integral components. The efficiency of each is to guarantee the non-proliferation regime in Kazakhstan. The components are the following: accounting, export and import control and physical protection of nuclear materials. First, the implementation of the goals of accounting and control bring into force, by the organization of the system for accounting and measurement of nuclear materials to determine present quantity. Organizing the accounting for nuclear material at facilities will ensure the efficiency of accountancy and reporting information. This defines the effectiveness of the state system for the accounting for the Kazakhstan's nuclear materials. Currently, Kazakhstan's nuclear material is fully safeguarded in designated secure locations. Kazakhstan has a nuclear power plant, 4 research reactors and a fuel fabrication plant. The governmental information system for nuclear materials control consist of two level: Governmental level - KAEA collects reports from facilities and prepares the reports for International Atomic Energy Agency, keeping of supporting documents and other necessary information, a data base of export and import, a data base of nuclear material inventory. Facility level - registration and processing information from key measurement points, formation the facility's nuclear materials accounting database. All facilities have computerized systems. Currently, all facilities are safeguarded under IAEA safeguarding standards, through IAEA inspections. Annually, IAEA verifies all nuclear materials at all Kazakhstan nuclear facilities. The government reporting system discloses the existence of all nuclear material and its transfer intended for interaction through the export control system and the nuclear control accounting system. Nuclear material export is regulated by the regulations of the Nuclear Export Control Law. The standard operating procedure is the primary means for

TOSHIBA CAE system for nuclear power plant

International Nuclear Information System (INIS)

Machiba, Hiroshi; Sasaki, Norio

1990-01-01

TOSHIBA aims to secure safety, increase reliability and improve efficiency through the engineering for nuclear power plant using Computer Aided Engineering (CAE). TOSHIBA CAE system for nuclear power plant consists of numbers of sub-systems which had been integrated centering around the Nuclear Power Plant Engineering Data Base (PDBMS) and covers all stage of engineering for nuclear power plant from project management, design, manufacturing, construction to operating plant service and preventive maintenance as it were 'Plant Life-Cycle CAE System'. In recent years, TOSHIBA has been devoting to extend the system for integrated intelligent CAE system with state-of-the-art computer technologies such as computer graphics and artificial intelligence. This paper shows the outline of CAE system for nuclear power plant in TOSHIBA. (author)

The Symmetric Rudin-Shapiro Transform

DEFF Research Database (Denmark)

Harbo, Anders La-Cour

2003-01-01

A method for constructing spread spectrum sequences is presented. The method is based on a linear, orthogonal, symmetric transform, the Rudin-Shapiro transform (RST), which is in many respects quite similar to the Haar wavelet packet transform. The RST provides the means for generating large sets...... of spread spectrum signals. This presentation provides a simple definition of the symmetric RST that leads to a fast N log(N) and numerically stable implementation of the transform....

Authenticated Blind Issuing of Symmetric Keys for Mobile Access Control System without Trusted Parties

Directory of Open Access Journals (Sweden)

Shin-Yan Chiou

2013-01-01

Full Text Available Mobile authentication can be used to verify a mobile user’s identity. Normally this is accomplished through the use of logon passwords, but this can raise the secret-key agreement problem between entities. This issue can be resolved by using a public-key cryptosystem, but mobile devices have limited computation ability and battery capacity and a PKI is needed. In this paper, we propose an efficient, non-PKI, authenticated, and blind issued symmetric key protocol for mobile access control systems. An easy-to-deploy authentication and authenticated key agreement system is designed such that empowered mobile devices can directly authorize other mobile devices to exchange keys with the server upon authentication using a non-PKI system without trusted parties. Empowered mobile users do not know the key value of the other mobile devices, preventing users from impersonating other individuals. Also, for security considerations, this system can revoke specific keys or keys issued by a specific user. The scheme is secure, efficient, and feasible and can be implemented in existing environments.

Unary self-verifying symmetric difference automata

CSIR Research Space (South Africa)

Marais, Laurette

2016-07-01

Full Text Available stream_source_info Marais_2016_ABSTRACT.pdf.txt stream_content_type text/plain stream_size 796 Content-Encoding ISO-8859-1 stream_name Marais_2016_ABSTRACT.pdf.txt Content-Type text/plain; charset=ISO-8859-1 18th... International Workshop on Descriptional Complexity of Formal Systems, 5 - 8 July 2016, Bucharest, Romania Unary self-verifying symmetric difference automata Laurette Marais1,2 and Lynette van Zijl1(B) 1 Department of Computer Science, Stellenbosch...

Acoustic interactions between inversion symmetric and asymmetric two-level systems

International Nuclear Information System (INIS)

Churkin, A; Schechter, M; Barash, D

2014-01-01

Amorphous solids, as well as many disordered lattices, display remarkable universality in their low temperature acoustic properties. This universality is attributed to the attenuation of phonons by tunneling two-level systems (TLSs), facilitated by the interaction of the TLSs with the phonon field. TLS-phonon interaction also mediates effective TLS–TLS interactions, which dictates the existence of a glassy phase and its low energy properties. Here we consider KBr:CN, the archetypal disordered lattice showing universality. We calculate numerically, using conjugate gradients method, the effective TLS–TLS interactions for inversion symmetric (CN flips) and asymmetric (CN rotations) TLSs, in the absence and presence of disorder, in two and three dimensions. The observed dependence of the magnitude and spatial power law of the interaction on TLS symmetry, and its change with disorder, characterizes TLS–TLS interactions in disordered lattices in both extreme and moderate dilutions. Our results are in good agreement with the two-TLS model, recently introduced to explain long-standing questions regarding the quantitative universality of phonon attenuation and the energy scale of ≈1–3 K below which universality is observed. (paper)

Preinspection of nuclear power plant systems

International Nuclear Information System (INIS)

1975-01-01

The general plans of the systems affecting the safety of the nuclear power plants are accepted by the Institute of Radiation Protection (IRP) on the basis of the preinspection of the systems. This is the prerequisite of the preinspection of the structures and components belonging to these systems. Exceptionally, when separately agreed, the IRP may perform the preinspection of a separate structure or component, although the preinspection documentation of the whole system, e.g. the nuclear heat generating system, has not been accepted. This guide applies to the nuclear power plant systems that have been defined to be preinspected in the classification document accepted by the IRP

Looking for symmetric Bell inequalities

OpenAIRE

Bancal, Jean-Daniel; Gisin, Nicolas; Pironio, Stefano

2010-01-01

Finding all Bell inequalities for a given number of parties, measurement settings and measurement outcomes is in general a computationally hard task. We show that all Bell inequalities which are symmetric under the exchange of parties can be found by examining a symmetrized polytope which is simpler than the full Bell polytope. As an illustration of our method, we generate 238 885 new Bell inequalities and 1085 new Svetlichny inequalities. We find, in particular, facet inequalities for Bell e...

The Symmetric Rudin-Shapiro Transform

DEFF Research Database (Denmark)

Harbo, Anders La-Cour

2003-01-01

A method for constructing spread spectrum sequences is presented. The method is based on a linear, orthogonal, and symmetric transform given as the Rudin-Shapiro transform (RST), which is in many respects quite similar to the Haar wavelet packet transform. The RST provides the means for generatin...... large sets of spread spectrum signals. This presentation provides a simple definition of the symmetric RST that leads to a fast N log(N) and numerically stable implementation of the transform....

Harmonic analysis on symmetric spaces

CERN Document Server

Terras, Audrey

This text explores the geometry and analysis of higher rank analogues of the symmetric spaces introduced in volume one. To illuminate both the parallels and differences of the higher rank theory, the space of positive matrices is treated in a manner mirroring that of the upper-half space in volume one. This concrete example furnishes motivation for the general theory of noncompact symmetric spaces, which is outlined in the final chapter. The book emphasizes motivation and comprehensibility, concrete examples and explicit computations (by pen and paper, and by computer), history, and, above all, applications in mathematics, statistics, physics, and engineering. The second edition includes new sections on Donald St. P. Richards’s central limit theorem for O(n)-invariant random variables on the symmetric space of GL(n, R), on random  matrix theory, and on advances in the theory of automorphic forms on arithmetic groups.

On isotropic cylindrically symmetric stellar models

International Nuclear Information System (INIS)

Nolan, Brien C; Nolan, Louise V

2004-01-01

We attempt to match the most general cylindrically symmetric vacuum spacetime with a Robertson-Walker interior. The matching conditions show that the interior must be dust filled and that the boundary must be comoving. Further, we show that the vacuum region must be polarized. Imposing the condition that there are no trapped cylinders on an initial time slice, we can apply a result of Thorne's and show that trapped cylinders never evolve. This results in a simplified line element which we prove to be incompatible with the dust interior. This result demonstrates the impossibility of the existence of an isotropic cylindrically symmetric star (or even a star which has a cylindrically symmetric portion). We investigate the problem from a different perspective by looking at the expansion scalars of invariant null geodesic congruences and, applying to the cylindrical case, the result that the product of the signs of the expansion scalars must be continuous across the boundary. The result may also be understood in relation to recent results about the impossibility of the static axially symmetric analogue of the Einstein-Straus model

78 FR 38739 - Special Nuclear Material Control and Accounting Systems for Nuclear Power Plants

Science.gov (United States)

2013-06-27

... Systems for Nuclear Power Plants AGENCY: Nuclear Regulatory Commission. ACTION: Regulatory guide; issuance... Guide (RG) 5.29, ``Special Nuclear Material Control and Accounting Systems for Nuclear Power Plants... material control and accounting. This guide applies to all nuclear power plants. ADDRESSES: Please refer to...

Nuclear energy an introduction to the concepts, systems, and applications of nuclear processes

CERN Document Server

Murray, Raymond L; Murphy, Arthur T; Rosenthal, Daniel I

1987-01-01

Nuclear Energy: An Introduction to the Concepts, Systems, and Applications of Nuclear Processes introduces the reader to the concepts, systems, and applications of nuclear processes. It provides a factual description of basic nuclear phenomena, as well as devices and processes that involve nuclear reactions. The problems and opportunities that are inherent in a nuclear age are also highlighted.Comprised of 27 chapters, this book begins with an overview of fundamental facts and principles, with emphasis on energy and states of matter, atoms and nuclei, and nuclear reactions. Radioactivi

Establishment of nuclear data evaluation system (I)

International Nuclear Information System (INIS)

Chang, Jong Hwa; Lee, Chang Kun; Kim, Jeong Do; Kim, Young Sik; Kim, Young Jin; Kim, Hyung Guk; Kil, Chung Sup; Kim, Kang Suk

1994-08-01

Nuclear data is fundamental data for development of new type of nuclear, upgrade of nuclear fuel, treatment of radwaste, research on fusion reactor, radioisotope usage, and nuclear medical therapy. Nuclear data is produced with experiments. However rack of experimental data for thousands of nuclides and various reaction types makes it essential to do statistical evaluation and theoretical interpolation. This study is intended to join international cooperation after establishing domestic basis for nuclear data evaluation work. This project is the first year of five year plan to do followings: 1) Establishment of database system to collect experimental data, 2) Setup of computer assistance system for evaluation work, 3) Verification of established system by test evaluation of selected nuclide reaction. The system has a collection of mass data of nuclides, computer codes for test evaluation of total cross section of 0-16 and collection of EXFOR format data for 0-16. This system will be improved continuously on next years. (Author)

Integrated nuclear and radiation protection systems

International Nuclear Information System (INIS)

Oprea, I.; Oprea, M.; Stoica, V.; Cerga, V.; Pirvu, V.; Badea, E.

1993-01-01

A multifunctional radiation monitoring equipment, flexible and capable to meet virtually environmental radiation monitoring, activity measurement and computational requirements, for nuclear laboratories has been designed. It can be used as a radiation protection system, for radionuclide measurement in isotope laboratories, nuclear technology, health physics and nuclear medicine, nuclear power stations and nuclear industry. The equipment is able to measure, transmit and record gamma dose rate and isotope activities. Other parameters and functions are optionally available, such as: self-contained alarm level, system self-test, dose integrator, syringe volume calculation for a given dose corrected for decay, calibration factor, 99 Mo assays performing and background subtraction

Study on interface between nuclear material accounting system and national nuclear forensic library

International Nuclear Information System (INIS)

Jeong, Yonhong; Han, Jae-Jun; Chang, Sunyoung; Shim, Hye-Won; Ahn, Seungho

2016-01-01

The implementation of nuclear forensics requires physical, chemical and radiological characteristics with transport history to unravel properties of seized nuclear materials. For timely assessment provided in the ITWG guideline, development of national response system (e.g., national nuclear forensic library) is strongly recommended. Nuclear material accounting is essential to obtain basic data in the nuclear forensic implementation phase from the perspective of nuclear non-proliferation related to the IAEA Safeguards and nuclear security. In this study, the nuclear material accounting reports were chosen due to its well-established procedure, and reviewed how to efficiently utilize the existing material accounting system to the nuclear forensic implementation phase In conclusion, limits and improvements in implementing the nuclear forensics were discussed. This study reviewed how to utilize the existing material accounting system for implementing nuclear forensics. Concerning item counting facility, nuclear material properties can be obtained based on nuclear material accounting information. Nuclear fuel assembly data being reported for the IAEA Safeguards can be utilized as unique identifier within the back-end fuel cycle. Depending upon the compulsory accountability report period, there exist time gaps. If national capabilities ensure that history information within the front-end nuclear fuel cycle is traceable particularly for the bulk handling facility, the entire cycle of national nuclear fuel would be managed in the framework of developing a national nuclear forensic library

Study on interface between nuclear material accounting system and national nuclear forensic library

Energy Technology Data Exchange (ETDEWEB)

Jeong, Yonhong; Han, Jae-Jun; Chang, Sunyoung; Shim, Hye-Won; Ahn, Seungho [Korea Institute of Nuclear Non-proliferation and Control, Daejeon (Korea, Republic of)

2016-10-15

The implementation of nuclear forensics requires physical, chemical and radiological characteristics with transport history to unravel properties of seized nuclear materials. For timely assessment provided in the ITWG guideline, development of national response system (e.g., national nuclear forensic library) is strongly recommended. Nuclear material accounting is essential to obtain basic data in the nuclear forensic implementation phase from the perspective of nuclear non-proliferation related to the IAEA Safeguards and nuclear security. In this study, the nuclear material accounting reports were chosen due to its well-established procedure, and reviewed how to efficiently utilize the existing material accounting system to the nuclear forensic implementation phase In conclusion, limits and improvements in implementing the nuclear forensics were discussed. This study reviewed how to utilize the existing material accounting system for implementing nuclear forensics. Concerning item counting facility, nuclear material properties can be obtained based on nuclear material accounting information. Nuclear fuel assembly data being reported for the IAEA Safeguards can be utilized as unique identifier within the back-end fuel cycle. Depending upon the compulsory accountability report period, there exist time gaps. If national capabilities ensure that history information within the front-end nuclear fuel cycle is traceable particularly for the bulk handling facility, the entire cycle of national nuclear fuel would be managed in the framework of developing a national nuclear forensic library.

Nuclear fuel element leak detection system

International Nuclear Information System (INIS)

John, C.D. Jr.

1978-01-01

Disclosed is a leak detection system integral with a wall of a building used to fabricate nuclear fuel elements for detecting radiation leakage from the nuclear fuel elements as the fuel elements exit the building. The leak detecting system comprises a shielded compartment constructed to withstand environmental hazards extending into a similarly constructed building and having sealed doors on both ends along with leak detecting apparatus connected to the compartment. The leak detecting system provides a system for removing a nuclear fuel element from its fabrication building while testing for radiation leaks in the fuel element

Fuel cycle of nuclear power plants and safeguards system of nuclear weapon nonproliferation

International Nuclear Information System (INIS)

Malek, Z.

1980-10-01

The international safeguard system of nuclear weapon nonproliferation and the IAEA safeguard system are briefly described. In Czechoslovakia, a decree was issued in 1977 governing the accounting for and control of nuclear materials. The contents of the decree are presented. Described are computer processing of accounting data, technical criteria for the safeguard system application, containment and inspection in the IAEA safeguard system. The method is shown of the control of and accounting for nuclear materials in nuclear power plants and in fuel manufacturing, reprocessing and enrichment plants. Nondestructive and destructive methods of nuclear materials analysis are discussed. Nondestructive methods used include gamma spectrometry, neutron techniques, X-ray fluores--cence techniques. (J.P.)

Time-invariant PT product and phase locking in PT -symmetric lattice models

Science.gov (United States)

Joglekar, Yogesh N.; Onanga, Franck Assogba; Harter, Andrew K.

2018-01-01

Over the past decade, non-Hermitian, PT -symmetric Hamiltonians have been investigated as candidates for both a fundamental, unitary, quantum theory and open systems with a nonunitary time evolution. In this paper, we investigate the implications of the former approach in the context of the latter. Motivated by the invariance of the PT (inner) product under time evolution, we discuss the dynamics of wave-function phases in a wide range of PT -symmetric lattice models. In particular, we numerically show that, starting with a random initial state, a universal, gain-site location dependent locking between wave-function phases at adjacent sites occurs in the PT -symmetry-broken region. Our results pave the way towards understanding the physically observable implications of time invariants in the nonunitary dynamics produced by PT -symmetric Hamiltonians.

Development of nuclear material accountancy control system

International Nuclear Information System (INIS)

Hirosawa, Naonori; Kashima, Sadamitsu; Akiba, Mitsunori

1992-01-01

PNC is developing a wide area of nuclear fuel cycle. Therefore, much nuclear material with a various form exists at each facility in the Works, and the controls of the inventory changes and the physical inventories of nuclear material are important. Nuclear material accountancy is a basic measure in safeguards system based on Non-Proliferation Treaty (NPT). In the light of such importance of material accountancy, the data base of nuclear material control and the material accountancy report system for all facilities has been developed by using the computer. By this system, accountancy report to STA is being presented certainly and timely. Property management and rapid corresponding to various inquiries can be carried out by the data base system which has free item searching procedure. (author)

Nuclear data evaluation method and evaluation system

International Nuclear Information System (INIS)

Liu Tingjin

1995-01-01

The evaluation methods and Nuclear Data Evaluation System have been developed in China. A new version of the system has been established on Micro-VAX2 computer, which is supported by IAEA under the technology assistance program. The flow chart of Chinese Nuclear Data Evaluation System is shown out. For last ten years, the main efforts have been put on the double differential cross section, covariance data and evaluated data library validation. The developed evaluation method and Chinese Nuclear Data Evaluation System have been widely used at CNDC and in Chinese Nuclear Data Network for CENDL. (1 tab., 15 figs.)

On the harmonic starlike functions with respect to symmetric ...

African Journals Online (AJOL)

In the present paper, we introduce the notions of functions harmonic starlike with respect to symmetric, conjugate and symmetric conjugate points. Such results as coefficient inequalities and structural formulae for these function classes are proved. Keywords: Harmonic functions, harmonic starlike functions, symmetric points, ...

Symmetric scrolled packings of multilayered carbon nanoribbons

Science.gov (United States)

Savin, A. V.; Korznikova, E. A.; Lobzenko, I. P.; Baimova, Yu. A.; Dmitriev, S. V.

2016-06-01

Scrolled packings of single-layer and multilayer graphene can be used for the creation of supercapacitors, nanopumps, nanofilters, and other nanodevices. The full atomistic simulation of graphene scrolls is restricted to consideration of relatively small systems in small time intervals. To overcome this difficulty, a two-dimensional chain model making possible an efficient calculation of static and dynamic characteristics of nanoribbon scrolls with allowance for the longitudinal and bending stiffness of nanoribbons is proposed. The model is extended to the case of scrolls of multilayer graphene. Possible equilibrium states of symmetric scrolls of multilayer carbon nanotribbons rolled up so that all nanoribbons in the scroll are equivalent are found. Dependences of the number of coils, the inner and outer radii, lowest vibrational eigenfrequencies of rolled packages on the length L of nanoribbons are obtained. It is shown that the lowest vibrational eigenfrequency of a symmetric scroll decreases with a nanoribbon length proportionally to L -1. It is energetically unfavorable for too short nanoribbons to roll up, and their ground state is a stack of plane nanoribbons. With an increasing number k of layers, the nanoribbon length L necessary for creation of symmetric scrolls increases. For a sufficiently small number of layers k and a sufficiently large nanoribbon length L, the scrolled packing has the lowest energy as compared to that of stack of plane nanoribbons and folded structures. The results can be used for development of nanomaterials and nanodevices on the basis of graphene scrolled packings.

Non-integrability of time-dependent spherically symmetric Yang-Mills equations

International Nuclear Information System (INIS)

Matinyan, S.G.; Prokhorenko, E.V.; Savvidy, G.K.

1986-01-01

The integrability of time-dependent spherically symmetric Yang-Mills equations is studied using the Fermi-Pasta-Ulam method. The phase space of this system is shown to have no quasi-periodic motion specific for integrable systems. In particular, the well-known Wu-Yang static solution is unstable, so its vicinity in phase is the stochasticity region

The protection system to Brazilian Nuclear Program

International Nuclear Information System (INIS)

Andreuzza, Mario Giussepp Santezzi Bertottelli

1997-01-01

The Sistema de Protecao ao Programa Nuclear Brasileiro-SIPRON (Protection System to Brazilian Nuclear Program) was established in 1980. It is intended to accomplish in only one system, all the actions related to security and protection for Nuclear Facilities in Brazil. The author presents in detail the protection system SIPRON, describing the system structure and organization, the functions and obligations of the system involved main organizations, as well as, the system operation and behaviour during an postulated occurrence of a nuclear emergency. It is also described an Exercise that happened in June of 1997 at the Nuclear Power Plant (NPP) Angra I, after two simulated tests in December of 1996 and April of 1997. The NPP Angra I Emergency Plan Exercise was a good opportunity to test the SIPRON structure and preparedness program. It was verified, included by International Atomic Energy Agency observers, the system involved organizations effectiveness and the procedures efficacy to protect the public and the environmental. Finally, it is shown the SIPRON activities of routine, the system obstacles and the expected future performances. (author)

Cotangent bundles over all the Hermitian symmetric spaces

International Nuclear Information System (INIS)

Arai, Masato; Baba, Kurando

2016-01-01

We construct the N = 2 supersymmetric nonlinear sigma models on the cotangent bundles over all the compact and non-compact Hermitian symmetric spaces. In order to construct them we use the projective superspace formalism which is an N = 2 off-shell superfield formulation in four-dimensional space-time. This formalism allows us to obtain the explicit expression of N = 2 supersymmetric nonlinear sigma models on the cotangent bundles over any Hermitian symmetric spaces in terms of the N =1 superfields, once the Kähler potentials of the base manifolds are obtained. Starting with N = 1 supersymmetric Kähler nonlinear sigma models on the Hermitian symmetric spaces, we extend them into the N = 2 supersymmetric models by using the projective superspace formalism and derive the general formula for the cotangent bundles over all the compact and non-compact Hermitian symmetric spaces. We apply to the formula for the non-compact Hermitian symmetric space E 7 /E 6 × U(1) 1 . (paper)

Ventilation-air conditioner system in nuclear power plant

International Nuclear Information System (INIS)

Kubota, Ryuji; Sugisaki, Toshihiko.

1989-01-01

This invention concerns a ventilation-air conditioner system which enables, upon occurrence of accidents in a nuclear power plant, continuous operation for other adjacent nuclear power plants with no effect of accidents. Air supply system and exhaust system are operated during usual operaiton. If loss of coolants accidents should occur in an adjacent nuclear power plants, operation is switched from ventilation operaiton to the operation of re-cycling system based on an AND logic of three signals, that is, a pressure HIGH signal for the reactor container, a water level LOW signal for the reactor and a radioactivity signal of the ventilation-air conditioner sytem on the side of air supply in the nuclear power plant. Thus, nuclear reactor buildings of the nuclear power plant are from the external atmosphere. Therefore, the radioactivity HIGH signal for switching to the emergency air conditioner system of the nuclear power plant is not actuated due to the loss of coolant accidents in the adjacent nuclear power plant. In addition, since the atmospheric temperature in the nuclear reactor building can be maintained by a cooling device disposed to the recycling system, reactor shutdown can be prevented. (I.S.)

Study on HVAC system in nuclear facility

International Nuclear Information System (INIS)

Baeg, S. Y.; Song, W. S.; Oh, Y. O.; Ju, Y. S.; Hong, K. P.

2003-01-01

Heating, Ventilation and Air Conditioning (HVAC) system in nuclear facility should be equipped and constructed more stable and allowable than that in common facility. The purpose of HVAC system is the maintenance of optimum working environment, the protection of worker against a contaminated air and the prevention of atmospheric contamination due to an outward ventilation, etc.. The basic scheme of a safety operation of nuclear facility is to prevent the atmospheric contamination even in low level. The adaptability of HVAC system which is in operation. In this study, the design requirements of HVAC system in nuclear facility and the HVAC systems in foreign countries are reviewed, and the results can be utilized in the design of HVAC system in nuclear facility

Symmetric waterbomb origami.

Science.gov (United States)

Chen, Yan; Feng, Huijuan; Ma, Jiayao; Peng, Rui; You, Zhong

2016-06-01

The traditional waterbomb origami, produced from a pattern consisting of a series of vertices where six creases meet, is one of the most widely used origami patterns. From a rigid origami viewpoint, it generally has multiple degrees of freedom, but when the pattern is folded symmetrically, the mobility reduces to one. This paper presents a thorough kinematic investigation on symmetric folding of the waterbomb pattern. It has been found that the pattern can have two folding paths under certain circumstance. Moreover, the pattern can be used to fold thick panels. Not only do the additional constraints imposed to fold the thick panels lead to single degree of freedom folding, but the folding process is also kinematically equivalent to the origami of zero-thickness sheets. The findings pave the way for the pattern being readily used to fold deployable structures ranging from flat roofs to large solar panels.

Symmetric modular torsatron

Science.gov (United States)

Rome, J.A.; Harris, J.H.

1984-01-01

A fusion reactor device is provided in which the magnetic fields for plasma confinement in a toroidal configuration is produced by a plurality of symmetrical modular coils arranged to form a symmetric modular torsatron referred to as a symmotron. Each of the identical modular coils is helically deformed and comprise one field period of the torsatron. Helical segments of each coil are connected by means of toroidally directed windbacks which may also provide part of the vertical field required for positioning the plasma. The stray fields of the windback segments may be compensated by toroidal coils. A variety of magnetic confinement flux surface configurations may be produced by proper modulation of the winding pitch of the helical segments of the coils, as in a conventional torsatron, winding the helix on a noncircular cross section and varying the poloidal and radial location of the windbacks and the compensating toroidal ring coils.

Study of Real Time Location System For Worker in Containment Building at Nuclear Power Plant

Energy Technology Data Exchange (ETDEWEB)

Lee, S. Y.; Kim, G. S. [Samchang Enterprise Company, Ulsan (Korea, Republic of); Kim, H. S. [Ulsan Univ., Ulsan (Korea, Republic of)

2012-03-15

Workers are required special management to minimize radiation exposure in nuclear power plant. Especially, there are many limitation in their activities at containment building in nuclear power plant. Test personnel shall administer the workers by tracing the location of them inside containment building in nuclear power plant. They may be exposed to the unnecessary radiation due to a complex and high radiation area in the building. Test personnel needs to manage efficiently for worker's safety and work hours at containment building. Therefore, it is critical for the test personnel to notice the risk to the workers by identifying the location when the workers are facing the dangerous situation on the high area. In this paper, we introduce requirements and design method to develop the one and two dimensional RTLS(Real Time Locating System) by using CSS(Chirp Spread Spectrum) which enables precise location measurement and robust data communication even indoor environment with serious electromagnetic interference caused by complicated structure such as the inside of containment building in the nuclear power plant. In the algorithm to compute the distance, it is suggested to use SDS-TWR(Symmetrical Double-Sided Two-Way Ranging) to solve the issue of indirect routes, and develop the power circuit with 10mW of designing gain for output power to meet the KCC standard in order to increase the raging distance, in addition, communication between Anchor and distance measuring computer shall be designed to increase energy using time of Tags(nodes) by using CAN(Controller Area Network) communication.

International Nuclear Information System in Malaysia

International Nuclear Information System (INIS)

Samsurdin Ahamad

1984-01-01

Practice of the International Nuclear Information System (INIS) in Malaysia is reviewed. The Nuclear Energy Unit, a participating representative of Malaysia, holds the responsibilities of disseminating information through this system. Its available services relevant to the aims of INIS are discussed

Modernizing computerized nuclear material accounting systems

International Nuclear Information System (INIS)

Erkkila, B.H.; Claborn, J.

1995-01-01

DOE Orders and draft orders for nuclear material control and accountability address a complete material control and accountability (MC and A) program for all DOE contractors processing, using, or storing nuclear materials. A critical element of an MC and A program is the accounting system used to track and record all inventories of nuclear material and movements of materials in those inventories. Most DOE facilities use computerized accounting systems to facilitate the task of accounting for all their inventory of nuclear materials. Many facilities still use a mixture of a manual paper system with a computerized system. Also, facilities may use multiple systems to support information needed for MC and A. For real-time accounting it is desirable to implement a single integrated data base management system for a variety of users. In addition to accountability needs, waste management, material management, and production operations must be supported. Information in these systems can also support criticality safety and other safety issues. Modern networked microcomputers provide extensive processing and reporting capabilities that single mainframe computer systems struggle with. This paper describes an approach being developed at Los Alamos to address these problems

Effect on the mean first passage time in symmetrical bistable systems by cross-correlation between noises

International Nuclear Information System (INIS)

Wang, J.; Cao, L.; Wu, D.J.

2003-01-01

We present an analytic investigation of the mean first passage time in two opposite directions (from the left well to the right well and from right to left) by studying symmetrical bistable systems driven by correlated Gaussian white noises, and prove that the mean first passage time in two opposite directions is not symmetrical any more when noises are correlated. As examples, the mean first passage time in the quartic bistable model and the sawtooth bistable model are calculated, respectively. From the analytic results of the mean first passage time, we testify further the relation T(from x - to x + ,λ)≠T(from x + to x - ,λ) in the same area of the parameter plan. Moreover, it is found that the dependences of T + (i.e., T(from x - to x + ,λ)) and T - (i.e., T(from x + to x - ,λ)) upon the multiplicative noise intensity Q and the additive noise intensity D exhibit entirely different properties. For same areas of the parameter plan: in the quartic bistable system, when the T + vs. Q curve exhibits a maximum, while the T - vs. Q curve is monotonous; when the T + vs. D curve is monotonous, while the T - vs. D curve experiences a phase transition from decreasing monotonously to possessing one minimum. Increasing Q, when the T + vs. D curve experiences a phase transition from decreasing monotonously to possessing one maximum, while the T - vs. D curve only increases monotonously. Similar behaviours also exist in the sawtooth bistable model

Virtual-Reality training system for nuclear security

International Nuclear Information System (INIS)

Nonaka, Nobuyuki

2012-01-01

At the Integrated Support Center for Nuclear Nonproliferation and Nuclear Security (ISCN) of the Japan Atomic Energy Agency, the virtual reality (VR) training system is under development for providing a practical training environment to implement experience-oriented and interactive lessons on nuclear security for wide range of participants in human resource development assistance program mainly to Asian emerging nuclear-power countries. This system electrically recreates and visualizes nuclear facilities and training conditions in stereoscopic (3D) view on a large-scale display (CAVE system) as virtual reality training facility (VR facility) and it provides training participants with effective environments to learn installation and layout of security equipment in the facility testing and verifying visually the protection performances under various situations such as changes in day-night lighting and weather conditions, which may lead to practical exercise in the design and evaluation of the physical protection system. This paper introduces basic concept of the system and outline of training programs as well as featured aspects in using the VR technology for the nuclear security. (author)

Isospin dependent properties of asymmetric nuclear matter

OpenAIRE

Chowdhury, P. Roy; Basu, D. N.; Samanta, C.

2009-01-01

The density dependence of nuclear symmetry energy is determined from a systematic study of the isospin dependent bulk properties of asymmetric nuclear matter using the isoscalar and the isovector components of density dependent M3Y interaction. The incompressibility $K_\\infty$ for the symmetric nuclear matter, the isospin dependent part $K_{asy}$ of the isobaric incompressibility and the slope $L$ are all in excellent agreement with the constraints recently extracted from measured isotopic de...

Nuclear power project management information system

International Nuclear Information System (INIS)

Zou Lailong; Zhang Peng; Xiao Ziyan; Chun Zengjun; Huang Futong

2001-01-01

Project Management Information System is an important infrastructure facility for the construction and operation of Nuclear Power Station. Based on the practice of Lingao nuclear power project management information system (NPMIS), the author describes the NPMIS design goals, system architecture and software functionality, points out the outline issues during the development and deployment of NPMIS

Symmetric structures of coherent states in superfluid helium-4

International Nuclear Information System (INIS)

Ahmad, M.

1981-02-01

Coherent States in superfluid helium-4 are discussed and symmetric structures are assigned to these states. Discrete and continuous series functions are exhibited for such states. Coherent State structure has been assigned to oscillating condensed bosons and their inter-relations and their effects on the superfluid system are analysed. (author)

Symmetric Imidazolium-Based Paramagnetic Ionic Liquids

Science.gov (United States)

2017-11-29

Charts N/A Unclassified Unclassified Unclassified SAR 14 Kamran Ghiassi N/A 1 Symmetric Imidazolium-Based Paramagnetic Ionic Liquids Kevin T. Greeson...NUMBER (Include area code) 29 November 2017 Briefing Charts 01 November 2017 - 30 November 2017 Symmetric Imidazolium-Based Paramagnetic Ionic ... Liquids K. Greeson, K. Ghiassi, J. Alston, N. Redeker, J. Marcischak, L. Gilmore, A. Guenthner Air Force Research Laboratory (AFMC) AFRL/RQRP 9 Antares

Nuclear-fueled circulatory support systems

Energy Technology Data Exchange (ETDEWEB)

Norman, J C [Texas Heart Inst. (USA)

1975-08-01

Experiments on calves using two types of systems for nuclear left ventricular assist pumps are described. These two systems use a nuclear heat source containing 120 g, 1600 Ci Pu-238 in the form of plutonium oxide. The heat source for the first system is the tidal regenerator engine with no valve or seal and is controlled using a hall effect displacement sensor. The second left ventricular assist system uses heat generated by nuclear decay for producing high gas pressure which is converted into a high hydraulic pressure for pumping. The engine efficiency amounts to 7 to 16%, and the measurement value of the pump efficiency obtained is 85%. How these two systems are synchronized with the left ventricle of vital body is described. IN a transplant experiment for a short period (175 hours) in the initial stage, the possibility of the present method was demonstrated. A long-term performance experiment and improvement of the systems are anticipated. However, there still remain many problems, such as improvement of efficiency, reliability, and performance and diminution of the size.

Development of a nuclear microprobe and its application to neurobiology

International Nuclear Information System (INIS)

Tapper, Staffan.

1989-01-01

A nuclear microprobe has been developed at the Pelletron accelerator in Lund. The design of the achromatic beam focusing system as well as of the beam scanning system is described. The focusing system consists of three magnetic- and three electrostatic quadrupole lenses together forming an chromatic quadrupole triplet with symmetric focusing properties. The beam quality from the accelerator has been improved by use of ultrathin stripper foils. The nuclear microprobe set-up has been applied to investigation of brain tissue specimens. The elemantal disorder following epileptic seizures has been studied by micro-PIXE analysis. A combination of macro- and micro-PIXE analysis have been utilized in an investigaiton of elemental differences between normal human brain and human brain tumours. In the context of the quantification procedure in micro-PIXE analysis, callibration and X-ray detector response function are discussed. (author)

Understanding Nuclear Safety Culture: A Systemic Approach

International Nuclear Information System (INIS)

Afghan, A.N.

2016-01-01

The Fukushima accident was a systemic failure (Report by Director General IAEA on the Fukushima Daiichi Accident). Systemic failure is a failure at system level unlike the currently understood notion which regards it as the failure of component and equipment. Systemic failures are due to the interdependence, complexity and unpredictability within systems and that is why these systems are called complex adaptive systems (CAS), in which “attractors” play an important role. If we want to understand the systemic failures we need to understand CAS and the role of these attractors. The intent of this paper is to identify some typical attractors (including stakeholders) and their role within complex adaptive system. Attractors can be stakeholders, individuals, processes, rules and regulations, SOPs etc., towards which other agents and individuals are attracted. This paper will try to identify attractors in nuclear safety culture and influence of their assumptions on safety culture behavior by taking examples from nuclear industry in Pakistan. For example, if the nuclear regulator is an attractor within nuclear safety culture CAS then how basic assumptions of nuclear plant operators and shift in-charges about “regulator” affect their own safety behavior?

Symmetric autocompensating quantum key distribution

Science.gov (United States)

Walton, Zachary D.; Sergienko, Alexander V.; Levitin, Lev B.; Saleh, Bahaa E. A.; Teich, Malvin C.

2004-08-01

We present quantum key distribution schemes which are autocompensating (require no alignment) and symmetric (Alice and Bob receive photons from a central source) for both polarization and time-bin qubits. The primary benefit of the symmetric configuration is that both Alice and Bob may have passive setups (neither Alice nor Bob is required to make active changes for each run of the protocol). We show that both the polarization and the time-bin schemes may be implemented with existing technology. The new schemes are related to previously described schemes by the concept of advanced waves.

Hyperons in nuclear matter from SU(3) chiral effective field theory

Energy Technology Data Exchange (ETDEWEB)

Petschauer, Stefan; Kaiser, Norbert [Technische Universitaet Muenchen (Germany); Haidenbauer, Johann [Forschungszentrum Juelich (Germany); Meissner, Ulf G. [Forschungszentrum Juelich (Germany); Universitaet Bonn (Germany); Weise, Wolfram [Technische Universitaet Muenchen (Germany); ECT, Trento (Italy)

2016-07-01

Brueckner theory is used to investigate the properties of hyperons in nuclear matter. The hyperon-nucleon interaction is taken from chiral effective field theory at next-to-leading order with SU(3) symmetric low-energy constants. Furthermore, the underlying nucleon-nucleon interaction is also derived within chiral effective field theory. We present the single-particle potentials of Λ and Σ hyperons in symmetric and asymmetric nuclear matter computed with the continuous choice for intermediate spectra. The results are in good agreement with the empirical information. In particular, our calculation gives a repulsive Σ-nuclear potential and a weak Λ-nuclear spin-orbit force. The splittings among the Σ{sup +}, Σ{sup 0} and Σ{sup -} potentials have a non-linear dependence on the isospin asymmetry which goes beyond the usual parametrization in terms of an isovector Lane potential.

Magnetospectroscopy of symmetric and anti-symmetric states in double quantum wells

Science.gov (United States)

Marchewka, M.; Sheregii, E. M.; Tralle, I.; Ploch, D.; Tomaka, G.; Furdak, M.; Kolek, A.; Stadler, A.; Mleczko, K.; Zak, D.; Strupinski, W.; Jasik, A.; Jakiela, R.

2008-02-01

The experimental results obtained for magnetotransport in the InGaAs/InAlAs double quantum well (DQW) structures of two different shapes of wells are reported. A beating effect occurring in the Shubnikov-de Haas (SdH) oscillations was observed for both types of structures at low temperatures in the parallel transport when the magnetic field was perpendicular to the layers. An approach for the calculation of the Landau level energies for DQW structures was developed and then applied to the analysis and interpretation of the experimental data related to the beating effect. We also argue that in order to account for the observed magnetotransport phenomena (SdH and integer quantum Hall effect), one should introduce two different quasi-Fermi levels characterizing two electron subsystems regarding the symmetry properties of their states, symmetric and anti-symmetric ones, which are not mixed by electron-electron interaction.

Systems integration processes for space nuclear electric propulsion systems

International Nuclear Information System (INIS)

Olsen, C.S.; Rice, J.W.; Stanley, M.L.

1991-01-01

The various components and subsystems that comprise a nuclear electric propulsion system should be developed and integrated so that each functions ideally and so that each is properly integrated with the other components and subsystems in the optimum way. This paper discusses how processes similar to those used in the development and intergration of the subsystems that comprise the Multimegawatt Space Nuclear Power System concepts can be and are being efficiently and effectively utilized for these purposes. The processes discussed include the development of functional and operational requirements at the system and subsystem level; the assessment of individual nuclear power supply and thruster concepts and their associated technologies; the conduct of systems integration efforts including the evaluation of the mission benefits for each system; the identification and resolution of concepts development, technology development, and systems integration feasibility issues; subsystem, system, and technology development and integration; and ground and flight subsystem and integrated system testing

Integrated engineering system for nuclear facilities building

International Nuclear Information System (INIS)

Tomura, H.; Miyamoto, A.; Futami, F.; Yasuda, S.; Ohtomo, T.

1995-01-01

In the construction of buildings for nuclear facilities in Japan, construction companies are generally in charge of the building engineering work, coordinating with plant engineering. An integrated system for buildings (PROMOTE: PROductive MOdeling system for Total nuclear Engineering) described here is a building engineering system including the entire life cycle of buildings for nuclear facilities. A Three-dimensional (3D) building model (PRO-model) is to be in the core of the system (PROMOTE). Data sharing in the PROMOTE is also done with plant engineering systems. By providing these basic technical foundations, PROMOTE is oriented toward offering rational, highquality engineering for the projects. The aim of the system is to provide a technical foundation in building engineering. This paper discusses the characteristics of buildings for nuclear facilities and the outline of the PROMOTE. (author)

Why nuclear geostorage systems for petroleum?

Energy Technology Data Exchange (ETDEWEB)

Harst, L van der; Knutson, C F [CER Geonuclear Corporation, Las Vegas, Nevada (United States)

1970-05-15

The objective of any kind of storage system in general is to act as a buffer between cyclical changes in supply and demand of the stored commodities. Since the advent of nuclear explosives engineering the possibility of constructing large-scale underground storage systems by means of contained nuclear explosions, for which the name nuclear geostorage has been coined, should be regarded as a valid alternative to the conventional storage systems currently in existence. Limiting this discussion to systems for storing crude oil, various options are available. The choice of any particular storage method depends, of course, on the circumstances surrounding each particular storage requirement; however, in many cases and for a variety of reasons, nuclear geostorage can be preferable to conventional solutions. Economic considerations are clearly among the most important ones. In this respect an increase in storage capacity will tend to favor the nuclear approach. Besides the economics, however, other considerations are important and may in some cases swing the balance in favor of nuclear geostorage plants, for instance: safety and strategic values, aesthetics, ease of access, lack of suitable tank farm space or lack of suitable geologic conditions for natural reservoirs. It should be borne in mind that the decision to use the nuclear approach to solve a storage problem can only be taken after satisfactory evaluation of the geological and geographical characteristics of the site, and when the technical, safety, political, and public relations factors can be handled adequately. (author)

Why nuclear geostorage systems for petroleum?

International Nuclear Information System (INIS)

Harst, L. van der; Knutson, C.F.

1970-01-01

The objective of any kind of storage system in general is to act as a buffer between cyclical changes in supply and demand of the stored commodities. Since the advent of nuclear explosives engineering the possibility of constructing large-scale underground storage systems by means of contained nuclear explosions, for which the name nuclear geostorage has been coined, should be regarded as a valid alternative to the conventional storage systems currently in existence. Limiting this discussion to systems for storing crude oil, various options are available. The choice of any particular storage method depends, of course, on the circumstances surrounding each particular storage requirement; however, in many cases and for a variety of reasons, nuclear geostorage can be preferable to conventional solutions. Economic considerations are clearly among the most important ones. In this respect an increase in storage capacity will tend to favor the nuclear approach. Besides the economics, however, other considerations are important and may in some cases swing the balance in favor of nuclear geostorage plants, for instance: safety and strategic values, aesthetics, ease of access, lack of suitable tank farm space or lack of suitable geologic conditions for natural reservoirs. It should be borne in mind that the decision to use the nuclear approach to solve a storage problem can only be taken after satisfactory evaluation of the geological and geographical characteristics of the site, and when the technical, safety, political, and public relations factors can be handled adequately. (author)

Hardware Realization of Chaos Based Symmetric Image Encryption

KAUST Repository

Barakat, Mohamed L.

2012-06-01

This thesis presents a novel work on hardware realization of symmetric image encryption utilizing chaos based continuous systems as pseudo random number generators. Digital implementation of chaotic systems results in serious degradations in the dynamics of the system. Such defects are illuminated through a new technique of generalized post proceeding with very low hardware cost. The thesis further discusses two encryption algorithms designed and implemented as a block cipher and a stream cipher. The security of both systems is thoroughly analyzed and the performance is compared with other reported systems showing a superior results. Both systems are realized on Xilinx Vetrix-4 FPGA with a hardware and throughput performance surpassing known encryption systems.

Perfectly invisible PT -symmetric zero-gap systems, conformal field theoretical kinks, and exotic nonlinear supersymmetry

Science.gov (United States)

Guilarte, Juan Mateos; Plyushchay, Mikhail S.

2017-12-01

We investigate a special class of the PT -symmetric quantum models being perfectly invisible zero-gap systems with a unique bound state at the very edge of continuous spectrum of scattering states. The family includes the PT -regularized two particle Calogero systems (conformal quantum mechanics models of de Alfaro-Fubini-Furlan) and their rational extensions whose potentials satisfy equations of the KdV hierarchy and exhibit, particularly, a behaviour typical for extreme waves. We show that the two simplest Hamiltonians from the Calogero subfamily determine the fluctuation spectra around the PT -regularized kinks arising as traveling waves in the field-theoretical Liouville and SU(3) conformal Toda systems. Peculiar properties of the quantum systems are reflected in the associated exotic nonlinear supersymmetry in the unbroken or partially broken phases. The conventional N=2 supersymmetry is extended here to the N=4 nonlinear supersymmetry that involves two bosonic generators composed from Lax-Novikov integrals of the subsystems, one of which is the central charge of the superalgebra. Jordan states are shown to play an essential role in the construction.

Filtering microfluidic bubble trains at a symmetric junction.

Science.gov (United States)

Parthiban, Pravien; Khan, Saif A

2012-02-07

We report how a nominally symmetric microfluidic junction can be used to sort all bubbles of an incoming train exclusively into one of its arms. The existence of this "filter" regime is unexpected, given that the junction is symmetric. We analyze this behavior by quantifying how bubbles modulate the hydrodynamic resistance in microchannels and show how speeding up a bubble train whilst preserving its spatial periodicity can lead to filtering at a nominally symmetric junction. We further show how such an asymmetric traffic of bubble trains can be triggered in symmetric geometries by identifying conditions wherein the resistance to flow decreases with an increase in the number of bubbles in the microchannel and derive an exact criterion to predict the same.

Entangling capabilities of symmetric two-qubit gates

Indian Academy of Sciences (India)

Com- putational investigation of entanglement of such ensembles is therefore impractical for ... the computational complexity. Pairs of spin-1 ... tensor operators which can also provide different symmetric logic gates for quantum pro- ... that five of the eight, two-qubit symmetric quantum gates expressed in terms of our newly.

Economic principles of optimizing mixed nuclear and non-nuclear electricity systems

International Nuclear Information System (INIS)

Gouni, L.

1984-01-01

In this chapter, an attempt will be made to show how and why, viewed from the economic angle, nuclear energy and electricity systems supplement each other, since the former requires large size facilities, and the latter provide already existing networks for the supply of all users. Consequently, it is primarily through the electric vector that the rational development of the nuclear industry may be ensured. Section 2.1 sets forth the essential rules for economic calculation. In Section 2.2 we discuss the competitive factors among final-use forms of energy in regard to utilization, and we attempt to show how nuclear energy transmitted through electricity systems may meet such terms. Finally, Section 2.3 deals with, and specifies the characteristics of, electricity systems based on nuclear energy and, in particular, the rates to which they lead. (author)

Nuclear technologies for local energy systems

International Nuclear Information System (INIS)

McDonnell, F.N.; Lynch, G.F.

1990-03-01

If nuclear energy is to realize its full potential as a safe and cost-effective alternative to fossil fuels, applications beyond those that are currently being serviced by large, central nuclear power stations must be identified and appropriate reactors developed. The Canadian program on reactor systems for local energy supply is at the forefront of these developments. This program emphasizes design simplicity, low power density and fuel rating, reliance on natural processes, passive systems, and reduced reliance on operator action. The first product, the SLOWPOKE Energy System, is a 10 MW heat source specifically designed to provide hot water to satisfy the needs of local heating systems for building complexes, institutions and municipal district heating systems. A demonstration heating reactor has been constructed at the Whiteshell Nuclear Research Establishment in Manitoba and has been undergoing an extensive test program since first operation in 1987 July. Based on the knowledge learned from the design, construction, licensing and operational testing of this facility, the design of the 10 MW commercial-size unit is well advanced, and Atomic Energy of Canada Limited is prepared to commit the construction of the first commercial unit. Although the technical demonstration of the concept is important, it is recognized that another crucial element is the public and regulatory acceptance of small nuclear systems in urban areas. The decision by a community to commit the construction of a SLOWPOKE Energy System brings to a sharp focus the current public apprehension about nuclear technologies

A cascaded three-phase symmetrical multistage voltage multiplier

International Nuclear Information System (INIS)

Iqbal, Shahid; Singh, G K; Besar, R; Muhammad, G

2006-01-01

A cascaded three-phase symmetrical multistage Cockcroft-Walton voltage multiplier (CW-VM) is proposed in this report. It consists of three single-phase symmetrical voltage multipliers, which are connected in series at their smoothing columns like string of batteries and are driven by three-phase ac power source. The smoothing column of each voltage multiplier is charged twice every cycle independently by respective oscillating columns and discharged in series through load. The charging discharging process completes six times a cycle and therefore the output voltage ripple's frequency is of sixth order of the drive signal frequency. Thus the proposed approach eliminates the first five harmonic components of load generated voltage ripples and sixth harmonic is the major ripple component. The proposed cascaded three-phase symmetrical voltage multiplier has less than half the voltage ripple, and three times larger output voltage and output power than the conventional single-phase symmetrical CW-VM. Experimental and simulation results of the laboratory prototype are given to show the feasibility of proposed cascaded three-phase symmetrical CW-VM

NCIS: a nuclear criticality information system

International Nuclear Information System (INIS)

Koponen, B.L.; Hampel, V.E.

1984-01-01

The NCIS is one of the developments carried out to meet the requirements in the field of criticality safety information. Its primary goal is to enhance nuclear criticality safety by dissemination of data, standards, and training material. This paper presents the ''NCIS'' progess since 1950: computer-searching, database management, nuclear critical experiments bibliography. American Nuclear Society transactions criticality safety publications compilation, edition of a personnel directory representing over 140 organizations located in 16 countries and showing a wide range of specialists involved in the field of nuclear criticality safety. The NCIS uses the information management and communication resources of TIS (Technology Information System): automated access procedures; creation of program-dependent information systems; communications. The NCIS is still in a growing, formative stage; it has concentrated first on collecting and organizing the nuclear criticality literature; nuclear critical data, calculational tools, standards, and training materials will follow. Finally the planned and contemplated resources are dealt with: expansion of bibliographic compilations; news database; fundamental criticality safety reference; criticality benchmarck database; user community; training resources; related resources; criticality accident database; dynamic databook; dynamic textbook; expert knowledge system; and, extraction of intelligence

Software Quality Assurance for Nuclear Safety Systems

International Nuclear Information System (INIS)

Sparkman, D R; Lagdon, R

2004-01-01

The US Department of Energy has undertaken an initiative to improve the quality of software used to design and operate their nuclear facilities across the United States. One aspect of this initiative is to revise or create new directives and guides associated with quality practices for the safety software in its nuclear facilities. Safety software includes the safety structures, systems, and components software and firmware, support software and design and analysis software used to ensure the safety of the facility. DOE nuclear facilities are unique when compared to commercial nuclear or other industrial activities in terms of the types and quantities of hazards that must be controlled to protect workers, public and the environment. Because of these differences, DOE must develop an approach to software quality assurance that ensures appropriate risk mitigation by developing a framework of requirements that accomplishes the following goals: (sm b ullet) Ensures the software processes developed to address nuclear safety in design, operation, construction and maintenance of its facilities are safe (sm b ullet) Considers the larger system that uses the software and its impacts (sm b ullet) Ensures that the software failures do not create unsafe conditions Software designers for nuclear systems and processes must reduce risks in software applications by incorporating processes that recognize, detect, and mitigate software failure in safety related systems. It must also ensure that fail safe modes and component testing are incorporated into software design. For nuclear facilities, the consideration of risk is not necessarily sufficient to ensure safety. Systematic evaluation, independent verification and system safety analysis must be considered for software design, implementation, and operation. The software industry primarily uses risk analysis to determine the appropriate level of rigor applied to software practices. This risk-based approach distinguishes safety

A study on optimization of the nuclear safety system

International Nuclear Information System (INIS)

Lee, Sang Hoon; Koh, Byung Joon; Kim, Jin Soo; Kim, Byoung Do; Cho, Seong Won; Kwon, Seog Kwon; Choi, Kwang Sik

1986-12-01

The number of nuclear facilities (nuclear power plants, research reactors, nuclear fuel facilities) under construction or in operation in Korea continues to increase and this has brought about increased importance and concerns toward nuclear safety in Korea. Also, domestic nuclear related organizations are increasingly carrying out the design/construction of nuclear power plants and the development /supply of nuclear fuels. In order to flexibly respond to these changes and to suggest direction to take, it is necessary to re-examine the current nuclear safety regulation system. This study is carried out in two stages and this report describes the results of the analysis and the assessment of the nuclear licencing system of such foreign countries as sweden and German, as the first of the two. In this regard, this study includes the analysis on the backgrounds on the choice of nuclear licensing system, the analysis on the licensing procedures, the analysis on the safety inspection system and the enforcement laws, the analysis on the structure and function of the regulatory, business and research organizations as well as the analysis on the relationship between the safety research and the regulatory duties. In this study, the German safety inspection system and the enforcement procedures and the Swedish nuclear licensing system are analyzed in detail. By comparing and assessing the finding with the current Korea Nuclear Licensing System, this study points out some reform measures of the Korean system that needs to improved. With the changing situations in mind, this study aims to develop the nuclear safety regulation system optimized for Korean situation by re-examining the current regulation system. (Author)

Recent space nuclear power systems

International Nuclear Information System (INIS)

Takizuka, Takakazu; Yasuda, Hideshi; Hishida, Makoto

1991-01-01

For the advance of mankind into the space, the power sources of large output are indispensable, and it has been considered that atomic energy is promising as compared with solar energy and others. Accordingly in USA and USSR, the development of the nuclear power generation systems for space use has been carried out since considerable years ago. In this report, the general features of space nuclear reactors are shown, and by taking the system for the SP-100 project being carried out in USA as the example, the contents of the recent design regarding the safety as an important factor are discussed. Moreover, as the examples of utilizing space nuclear reactors, the concepts of the power source for the base on the moon, the sources of propulsive power for the rockets used for Mars exploration and others, the remote power transmission system by laser in the space and so on are explained. In September, 1988, the launching of a space shuttle of USA was resumed, and the Jupiter explorer 'Galileo' and the space telescope 'Hubble' were successfully launched. The space station 'Mir' of USSR has been used since February, 1986. The history of the development of the nuclear power generation systems for space use is described. (K.I.)

International Nuclear Information System 25 years

International Nuclear Information System (INIS)

Behrens, H.; Prinz, H.

1996-01-01

In May 1970, the first information was published in the International Nuclear Information System (Inis). This makes Inis the first system in the world to establish a decentralized international database. In creating Inis, the International Atomic Energy Agency wanted to promote the exchange of information about the peaceful uses of nuclear energy among its members. References to the nuclear literature were to be compiled in the most complete way possible. The number of IAEA member countries participating in Inis has increased from an original 38 to 90, that of international organizations, from 12 to 17. The database holds more than 1.8 million documentation units; stocks grow by some 75,000 units annually. The German literature about nuclear research and nuclear technology is collected, evaluated and entered into Inis by the Fachinformationszentrum Karlsruhe. (orig.) [de

Scottish Nuclear's information systems strategy

International Nuclear Information System (INIS)

Inglis, P.

1991-01-01

Scottish Nuclear, the company which has owned and operated Scotland's nuclear power generating capacity since privatization, inherited a substantial amount of computer hardware and software from its predecessor, the South of Scotland Electricity Board. Each of the two power stations, Torness and Hunterston, were using Digital Vax clusters as the Scottish Nuclear company was formed. This had a major influence on the information systems strategy which has subsequently been adopted. (UK)

Study of nuclear reactions involving heavy nuclei and intermediate- and high-energy protons and an application in nuclear reactor physics (ADS)

International Nuclear Information System (INIS)

Matuoka, Paula Fernanda Toledo

2016-01-01

In the present work, intermediate- and high-energy nuclear reactions involving heavy nuclei and protons were studied with the Monte Carlo CRISP (Rio - Ilheus - Sao Paulo Collaboration) model. The most relevant nuclear processes studied were intranuclear cascade and fission-evaporation competition. Preliminary studies showed fair agreement between CRISP model calculation and experimental data of multiplicity of evaporated neutrons (E 20 MeV) were emitted mostly in the intranuclear cascade stage, while evaporation presented larger neutron multiplicity. Fission cross section of 209 mb and spallation cross section of 1788 mb were calculated { both in agreement with experimental data. The fission process resulted in a symmetric mass distribution. Another Monte Carlo code, MCNP, was used for radiation transport in order to understand the role of a spallation neutron source in a ADS (Accelerator Driven System) nuclear reactor. Initially, a PWR reactor was simulated to study the isotopic compositions in spent nuclear fuel. As a rst attempt, a spallation neutron source was adapted to an industrial size nuclear reactor. The results showed no evidence of incineration of transuranic elements and modifications were suggested. (author)

Expert system for nuclear power plant feedwater system diagnosis

International Nuclear Information System (INIS)

Meguro, R.; Kinoshita, Y.; Sato, T.; Yokota, Y.; Yokota, M.

1987-01-01

The Expert System for Nuclear Power Plant Feedwater System Diagnosis has been developed to assist maintenance engineers in nuclear power plants. This system adopts the latest process computer TOSBAC G8050 and the expert system developing tool TDES2, and has a large scale knowledge base which consists of the expert knowledge and experience of engineers in many fields. The man-machine system, which has been developed exclusively for diagnosis, improves the man-machine interface and realizes the graphic displays of diagnostic process and path, stores diagnostic results and searches past reference

An approach to a self-consistent nuclear energy system

International Nuclear Information System (INIS)

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

1992-01-01

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

Synthesis & Characterization of New bis-Symmetrical Adipoyl ...

African Journals Online (AJOL)

Full Title: Synthesis and Characterization of New bis-Symmetrical Adipoyl, Terepthaloyl, Chiral Diimido-di-L-alanine Diesters and Chiral Phthaloyl-L-alanine Ester of Tripropoxy p-tert-Butyl Calix[4]arene and Study of Their Hosting Ability for Alanine and Na+. Bis-symmetrical tripropoxy p-tert-butyl calix[4]arene esters were ...

The national nuclear material tracking system. A Korea's countermeasure against nuclear terrorism

Energy Technology Data Exchange (ETDEWEB)

Moon, Joo Hyun [Dongguk Univ., Gyeongbuk (Korea, Republic of)

2011-07-15

Since nuclear terrorism has been identified as a real threat, the Korean government has earnestly developed elementary technologies and sub-systems for establishing an integrated defensive system against nuclear terrorism, which is based on the concept of defense-in-depth. This paper introduces the gist and implications of the studies that have been conducted in building the national nuclear material tracking system for preventing and intercepting the illicit trafficking and transporting of nuclear material in Korea. (orig.)

Looking for symmetric Bell inequalities

Energy Technology Data Exchange (ETDEWEB)

Bancal, Jean-Daniel; Gisin, Nicolas [Group of Applied Physics, University of Geneva, 20 rue de l' Ecole-de Medecine, CH-1211 Geneva 4 (Switzerland); Pironio, Stefano, E-mail: jean-daniel.bancal@unige.c [Laboratoire d' Information Quantique, Universite Libre de Bruxelles (Belgium)

2010-09-24

Finding all Bell inequalities for a given number of parties, measurement settings and measurement outcomes is in general a computationally hard task. We show that all Bell inequalities which are symmetric under the exchange of parties can be found by examining a symmetrized polytope which is simpler than the full Bell polytope. As an illustration of our method, we generate 238 885 new Bell inequalities and 1085 new Svetlichny inequalities. We find, in particular, facet inequalities for Bell experiments involving two parties and two measurement settings that are not of the Collins-Gisin-Linden-Massar-Popescu type.

Looking for symmetric Bell inequalities

International Nuclear Information System (INIS)

Bancal, Jean-Daniel; Gisin, Nicolas; Pironio, Stefano

2010-01-01

Finding all Bell inequalities for a given number of parties, measurement settings and measurement outcomes is in general a computationally hard task. We show that all Bell inequalities which are symmetric under the exchange of parties can be found by examining a symmetrized polytope which is simpler than the full Bell polytope. As an illustration of our method, we generate 238 885 new Bell inequalities and 1085 new Svetlichny inequalities. We find, in particular, facet inequalities for Bell experiments involving two parties and two measurement settings that are not of the Collins-Gisin-Linden-Massar-Popescu type.

Diagrams for symmetric product orbifolds

International Nuclear Information System (INIS)

Pakman, Ari; Rastelli, Leonardo; Razamat, Shlomo S.

2009-01-01

We develop a diagrammatic language for symmetric product orbifolds of two-dimensional conformal field theories. Correlation functions of twist operators are written as sums of diagrams: each diagram corresponds to a branched covering map from a surface where the fields are single-valued to the base sphere where twist operators are inserted. This diagrammatic language facilitates the study of the large N limit and makes more transparent the analogy between symmetric product orbifolds and free non-abelian gauge theories. We give a general algorithm to calculate the leading large N contribution to four-point correlators of twist fields.

The Axially Symmetric One-Monopole

International Nuclear Information System (INIS)

Wong, K.-M.; Teh, Rosy

2009-01-01

We present new classical generalized one-monopole solution of the SU(2) Yang-Mills-Higgs theory with the Higgs field in the adjoint representation. We show that this solution with θ-winding number m = 1 and φ-winding number n = 1 is an axially symmetric generalization of the 't Hooft-Polyakov one-monopole. We construct this axially symmetric one-monopole solution by generalizing the large distance asymptotic solutions of the 't Hooft-Polyakov one-monopole to the Jacobi elliptic functions and solving the second order equations of motion numerically when the Higgs potential is vanishing. This solution is a non-BPS solution.

Commutative curvature operators over four-dimensional generalized symmetric

Directory of Open Access Journals (Sweden)

Ali Haji-Badali

2014-12-01

Full Text Available Commutative properties of four-dimensional generalized symmetric pseudo-Riemannian manifolds were considered. Specially, in this paper, we studied Skew-Tsankov and Jacobi-Tsankov conditions in 4-dimensional pseudo-Riemannian generalized symmetric manifolds.

Nuclear matter from effective quark-quark interaction.

Science.gov (United States)

Baldo, M; Fukukawa, K

2014-12-12

We study neutron matter and symmetric nuclear matter with the quark-meson model for the two-nucleon interaction. The Bethe-Bruckner-Goldstone many-body theory is used to describe the correlations up to the three hole-line approximation with no extra parameters. At variance with other nonrelativistic realistic interactions, the three hole-line contribution turns out to be non-negligible and to have a substantial saturation effect. The saturation point of nuclear matter, the compressibility, the symmetry energy, and its slope are within the phenomenological constraints. Since the interaction also reproduces fairly well the properties of the three-nucleon system, these results indicate that the explicit introduction of the quark degrees of freedom within the considered constituent quark model is expected to reduce the role of three-body forces.

Future development of nuclear energy systems

Energy Technology Data Exchange (ETDEWEB)

NONE

2001-03-01

Nuclear energy development in Japan has passed about 30 years, and reaches to a step to supply about 35 % of total electric power demand. However, together with globalization of economic and technical development, its future progressing method is required for its new efforts. Among such conditions, when considering a state of future type nuclear energy application, its contribution to further environmental conservation and international cooperation is essential, and it is required for adoption to such requirement how it is made an energy source with excellent economics.The Research Committee on 'Engineering Design on Nuclear Energy Systems' established under recognition in 1998 has been carried out some discussions on present and future status of nuclear energy development. And so forth under participation of outer specialists. Here were summarized on two year's committee actions containing them and viewpoints of nuclear industries, popularization of nuclear system technology, and so forth. (G.K.)

Defense nuclear energy systems selection methodology for civil nuclear power applications

International Nuclear Information System (INIS)

Scarborough, J.C.

1986-01-01

A methodology developed to select a preferred nuclear power system for a US Department of Defense (DOD) application has been used to evaluate preferred nuclear power systems for a remote island community in Southeast Asia. The plant would provide ∼10 MW of electric power, possibly low-temperature process heat for the local community, and would supplement existing island diesel electric capacity. The nuclear power system evaluation procedure was evolved from a disciplined methodology for ranking ten nuclear power designs under joint development by the US Department of Energy (DOE) and DOD. These included six designs proposed by industry for the Secure Military Power Plant Program (now termed Multimegawatt Terrestrial Reactor Program), the SP-100 Program, the North Warning System Program, and the Modular Advanced High-Temperature Gas-Cooled Reactor (HTGR) and Liquid-Metal Reactor (LMR) programs. The 15 evaluation criteria established for the civil application were generally similar to those developed and used for the defense energy systems evaluation, except that the weighting factor applied to each individual criterion differed. The criteria and their weighting (importance) functions for the civil application are described

Remote system for counting of nuclear pulses

International Nuclear Information System (INIS)

Nieves V, J.A.; Garcia H, J.M.; Aguilar B, M.A.

1999-01-01

In this work, it is describe technically the remote system for counting of nuclear pulses, an integral system of the project radiological monitoring in a petroleum distillation tower. The system acquires the counting of incident nuclear particles in a nuclear detector which process this information and send it in serial form, using the RS-485 toward a remote receiver, which can be a Personal computer or any other device capable to interpret the communication protocol. (Author)

The regulatory system of nuclear safety in Russia

International Nuclear Information System (INIS)

Mizoguchi, Shuhei

2013-01-01

This article explains what type of mechanism the nuclear system has and how nuclear safety is regulated in Russia. There are two main organizations in this system : ROSATOM and ROSTEKHADZOR. ROSATOM, which was founded in 2007, incorporates all the nuclear industries in Russia, including civil nuclear companies as well as nuclear weapons complex facilities. ROSTEKHNADZOR is the federal body that secures and supervises the safety in using atomic energy. This article also reviews three laws on regulating nuclear safety. (author)

Containments for consolidated nuclear steam systems

International Nuclear Information System (INIS)

Jabsen, F.S.

1978-01-01

A containment system for a consolidated nuclear steam system incorporating a nuclear core, steam generator and reactor coolant pumps within a single pressure vessel is described which is designed to provide radiation shielding and pressure suppression. Design details, including those for the dry well and wet well of the containment, are given. (UK)

Spherical aberration correction with threefold symmetric line currents.

Science.gov (United States)

Hoque, Shahedul; Ito, Hiroyuki; Nishi, Ryuji; Takaoka, Akio; Munro, Eric

2016-02-01

It has been shown that N-fold symmetric line current (henceforth denoted as N-SYLC) produces 2N-pole magnetic fields. In this paper, a threefold symmetric line current (N3-SYLC in short) is proposed for correcting 3rd order spherical aberration of round lenses. N3-SYLC can be realized without using magnetic materials, which makes it free of the problems of hysteresis, inhomogeneity and saturation. We investigate theoretically the basic properties of an N3-SYLC configuration which can in principle be realized by simple wires. By optimizing the parameters of a system with beam energy of 5.5keV, the required excitation current for correcting 3rd order spherical aberration coefficient of 400 mm is less than 1AT, and the residual higher order aberrations can be kept sufficiently small to obtain beam size of less than 1 nm for initial slopes up to 5 mrad. Copyright © 2015 Elsevier B.V. All rights reserved.

Two-stage solar concentrators based on parabolic troughs: asymmetric versus symmetric designs.

Science.gov (United States)

Schmitz, Max; Cooper, Thomas; Ambrosetti, Gianluca; Steinfeld, Aldo

2015-11-20

While nonimaging concentrators can approach the thermodynamic limit of concentration, they generally suffer from poor compactness when designed for small acceptance angles, e.g., to capture direct solar irradiation. Symmetric two-stage systems utilizing an image-forming primary parabolic concentrator in tandem with a nonimaging secondary concentrator partially overcome this compactness problem, but their achievable concentration ratio is ultimately limited by the central obstruction caused by the secondary. Significant improvements can be realized by two-stage systems having asymmetric cross-sections, particularly for 2D line-focus trough designs. We therefore present a detailed analysis of two-stage line-focus asymmetric concentrators for flat receiver geometries and compare them to their symmetric counterparts. Exemplary designs are examined in terms of the key optical performance metrics, namely, geometric concentration ratio, acceptance angle, concentration-acceptance product, aspect ratio, active area fraction, and average number of reflections. Notably, we show that asymmetric designs can achieve significantly higher overall concentrations and are always more compact than symmetric systems designed for the same concentration ratio. Using this analysis as a basis, we develop novel asymmetric designs, including two-wing and nested configurations, which surpass the optical performance of two-mirror aplanats and are comparable with the best reported 2D simultaneous multiple surface designs for both hollow and dielectric-filled secondaries.

Development of the Advanced Nuclear Safety Information Management (ANSIM) System

Energy Technology Data Exchange (ETDEWEB)

Sohn, Jae Min; Ko, Young Cheol; Song, Tai Gil [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2012-05-15

Korea has become a technically independent nuclear country and has grown into an exporter of nuclear technologies. Thus, nuclear facilities are increasing in significance at KAERI (Korea Atomic Energy Research Institute), and it is time to address the nuclear safety. The importance of nuclear safety cannot be overemphasized. Therefore, a management system is needed urgently to manage the safety of nuclear facilities and to enhance the efficiency of nuclear information. We have established ISP (Information Strategy Planning) for the Integrated Information System of nuclear facility and safety management. The purpose of this paper is to develop a management system for nuclear safety. Therefore, we developed the Advanced Nuclear Safety Information Management system (hereinafter referred to as the 'ANSIM system'). The ANSIM system has been designed and implemented to computerize nuclear safety information for standardization, integration, and sharing in real-time. Figure 1 shows the main home page of the ANSIM system. In this paper, we describe the design requirements, contents, configurations, and utilizations of the ANSIM system

Risk and safety analysis of nuclear systems

National Research Council Canada - National Science Library

Lee, John C; McCormick, Norman J

2011-01-01

...), and failure modes of systems. All of this material is general enough that it could be used in non-nuclear applications, although there is an emphasis placed on the analysis of nuclear systems...

Crossing-symmetric solutions to low equations

International Nuclear Information System (INIS)

McLeod, R.J.; Ernst, D.J.

1985-01-01

Crossing symmetric models of the pion-nucleon interaction in which crossing symmetry is kept to lowest order in msub(π)/msub(N) are investigated. Two iterative techniques are developed to solve the crossing-symmetric Low equation. The techniques are used to solve the original Chew-Low equations and their generalizations to include the coupling to the pion-production channels. Small changes are found in comparison with earlier results which used an iterative technique proposed by Chew and Low and which did not produce crossing-symmetric results. The iterative technique of Chew and Low is shown to fail because of its inability to produce zeroes in the amplitude at complex energies while physical solutions to the model require such zeroes. We also prove that, within the class of solutions such that phase shifts approach zero for infinite energy, the solution to the Low equation is unique. (orig.)

Equation of state of dense nuclear matter and neutron star structure from nuclear chiral interactions

Science.gov (United States)

Bombaci, Ignazio; Logoteta, Domenico

2018-02-01

Aims: We report a new microscopic equation of state (EOS) of dense symmetric nuclear matter, pure neutron matter, and asymmetric and β-stable nuclear matter at zero temperature using recent realistic two-body and three-body nuclear interactions derived in the framework of chiral perturbation theory (ChPT) and including the Δ(1232) isobar intermediate state. This EOS is provided in tabular form and in parametrized form ready for use in numerical general relativity simulations of binary neutron star merging. Here we use our new EOS for β-stable nuclear matter to compute various structural properties of non-rotating neutron stars. Methods: The EOS is derived using the Brueckner-Bethe-Goldstone quantum many-body theory in the Brueckner-Hartree-Fock approximation. Neutron star properties are next computed solving numerically the Tolman-Oppenheimer-Volkov structure equations. Results: Our EOS models are able to reproduce the empirical saturation point of symmetric nuclear matter, the symmetry energy Esym, and its slope parameter L at the empirical saturation density n0. In addition, our EOS models are compatible with experimental data from collisions between heavy nuclei at energies ranging from a few tens of MeV up to several hundreds of MeV per nucleon. These experiments provide a selective test for constraining the nuclear EOS up to 4n0. Our EOS models are consistent with present measured neutron star masses and particularly with the mass M = 2.01 ± 0.04 M⊙ of the neutron stars in PSR J0348+0432.

Robust Solvers for Symmetric Positive Definite Operators and Weighted Poincaré Inequalities

KAUST Repository

Efendiev, Yalchin; Galvis, Juan; Lazarov, Raytcho; Willems, Joerg

2012-01-01

An abstract setting for robustly preconditioning symmetric positive definite (SPD) operators is presented. The term "robust" refers to the property of the condition numbers of the preconditioned systems being independent of mesh parameters

Evaluation of collapsed cone convolution superposition (CCCS algorithms in prowess treatment planning system for calculating symmetric and asymmetric field size

Directory of Open Access Journals (Sweden)

Tamer Dawod

2015-01-01

Full Text Available Purpose: This work investigated the accuracy of prowess treatment planning system (TPS in dose calculation in a homogenous phantom for symmetric and asymmetric field sizes using collapse cone convolution / superposition algorithm (CCCS. Methods: The measurements were carried out at source-to-surface distance (SSD set to 100 cm for 6 and 10 MV photon beams. Data for a full set of measurements for symmetric fields and asymmetric fields, including inplane and crossplane profiles at various depths and percentage depth doses (PDDs were obtained during measurements on the linear accelerator.Results: The results showed that the asymmetric collimation dose lead to significant errors (up to approximately 7% in dose calculations if changes in primary beam intensity and beam quality. It is obvious that the most difference in the isodose curves was found in buildup and the penumbra regions. Conclusion: The results showed that the dose calculation using Prowess TPS based on CCCS algorithm is generally in excellent agreement with measurements.

Basic study for development of nuclear heat application systems

Energy Technology Data Exchange (ETDEWEB)

Inaba, Yoshitomo; Fumizawa, Motoo; Hishida, Makoto [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment] [and others

1996-05-01

We need to intensely investigate real possibilities of nuclear heat application systems which exploit high potential of nuclear energy as a promising candidate of the future energy resource in the world. In this report, special interest was placed on coal reforming systems because we thought a compact heat source of nuclear power with a very high energy density might compensate the environmental problem caused by burning a great amount of coal. First, we reviewed state-of-the-art technologies for coal reforming technology with a special attention on coal gasification technologies. Based on these basic data, we proposed several nuclear coal reforming systems and discussed advantages and disadvantages of the systems. We also explored a model with which we could analyze nuclear heat application systems all together. In addition, we investigated possibility and effects of nuclear heat utilization systems producing chemical materials from carbon dioxide in flue gas of fossil fuel power plant. As a result, we showed nuclear heat application systems were useful. (author).

Radon transformation on reductive symmetric spaces:Support theorems

DEFF Research Database (Denmark)

Kuit, Job Jacob

2013-01-01

We introduce a class of Radon transforms for reductive symmetric spaces, including the horospherical transforms, and derive support theorems for these transforms. A reductive symmetric space is a homogeneous space G/H for a reductive Lie group G of the Harish-Chandra class, where H is an open sub...... is based on the relation between the Radon transform and the Fourier transform on G/H, and a Paley–Wiener-shift type argument. Our results generalize the support theorem of Helgason for the Radon transform on a Riemannian symmetric space....

Remote nuclear green pellet processing system

International Nuclear Information System (INIS)

Cellier, Francis.

1980-01-01

An automated system for manufacturing nuclear fuel pellets for use in nuclear fuel elements of nuclear power reactors is described. The system comprises process components arranged vertically but not directly under each other within a single enclosure. The vertical-lateral arrangement provides for gravity flow of the product from one component to the next and for removal of each component without interference with the other components. The single enclosure eliminates time consuming transfer between separate enclosures of each component while providing three-sided access to the component through glove ports. (auth)

Soft systems methodology as a systemic approach to nuclear safety management

International Nuclear Information System (INIS)

Vieira Neto, Antonio S.; Guilhen, Sabine N.; Rubin, Gerson A.; Caldeira Filho, Jose S.; Camargo, Iara M.C.

2017-01-01

Safety approach currently adopted by nuclear installations is built almost exclusively upon analytical methodologies based, mainly, on the belief that the properties of a system, such as its safety, are given by its constituent parts. This approach, however, does not properly address the complex dynamic interactions between technical, human and organizational factors occurring within and outside the organization. After the accident at Fukushima Daiichi nuclear power plant in March 2011, experts of the International Atomic Energy Agency (IAEA) recommended a systemic approach as a complementary perspective to nuclear safety. The aim of this paper is to present an overview of the systems thinking approach and its potential use for structuring socio technical problems involved in the safety of nuclear installations, highlighting the methodologies related to the soft systems thinking, in particular the Soft Systems Methodology (SSM). The implementation of a systemic approach may thus result in a more holistic picture of the system by the complex dynamic interactions between technical, human and organizational factors. (author)

Soft systems methodology as a systemic approach to nuclear safety management

Energy Technology Data Exchange (ETDEWEB)

Vieira Neto, Antonio S.; Guilhen, Sabine N.; Rubin, Gerson A.; Caldeira Filho, Jose S.; Camargo, Iara M.C., E-mail: asvneto@ipen.br, E-mail: snguilhen@ipen.br, E-mail: garubin@ipen.br, E-mail: jscaldeira@ipen.br, E-mail: icamargo@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNE-SP), Sao Paulo, SP (Brazil)

2017-07-01

Safety approach currently adopted by nuclear installations is built almost exclusively upon analytical methodologies based, mainly, on the belief that the properties of a system, such as its safety, are given by its constituent parts. This approach, however, does not properly address the complex dynamic interactions between technical, human and organizational factors occurring within and outside the organization. After the accident at Fukushima Daiichi nuclear power plant in March 2011, experts of the International Atomic Energy Agency (IAEA) recommended a systemic approach as a complementary perspective to nuclear safety. The aim of this paper is to present an overview of the systems thinking approach and its potential use for structuring socio technical problems involved in the safety of nuclear installations, highlighting the methodologies related to the soft systems thinking, in particular the Soft Systems Methodology (SSM). The implementation of a systemic approach may thus result in a more holistic picture of the system by the complex dynamic interactions between technical, human and organizational factors. (author)

Simulation of a Nuclear Steam Supply System (NSSS) of a PWR nuclear power plant

International Nuclear Information System (INIS)

Reis Martins Junior, L.L. dos.

1980-01-01

The following work intends to perform the digital simulation, of the Nuclear Steam Supply System (NSSS) of a PWR nuclear power plant for control systems design and analysis purposes. There are mathematical models for the reactor, the steam generator, the pressurizer and for transport lags of the coolant in the primary circuit. Nevertheless no one control system has been considered to permit any user the inclusion in the more convenient way of the desired control systems' models. The characteristics of the system in consideration are fundamentally equal to the ones of Almirante Alvaro Alberto Nuclear Power Plant, Unit I (Angra I) obtained in the Final Safety Analysis Report at Comissao Nacional de Energia Nuclear. (author)

Process information systems in nuclear reprocessing

International Nuclear Information System (INIS)

Jaeschke, A.; Keller, H.; Orth, H.

1987-01-01

On a production management level, a process information system in a nuclear reprocessing plant (NRP) has to fulfill conventional operating functions and functions for nuclear material surveillance (safeguards). Based on today's state of the art of on-line process control technology, the progress in hardware and software technology allows to introduce more process-specific intelligence into process information systems. Exemplified by an expert-system-aided laboratory management system as component of a NRP process information system, the paper demonstrates that these technologies can be applied already. (DG) [de

European nuclear data studies for fast systems

International Nuclear Information System (INIS)

Rullhusen, P.; Hambsch, F.-J.; Mondelaers, W.; Plompen, A.J.M.; Schillebeeckx, P.

2010-01-01

Nuclear data needs for fast systems are highlighted and the following projects are described: Joint European research projects: MUSE Experiments for Sub-critical Neutronics Validation; High- and Intermediate Energy Nuclear Data for ADS (HINDAS); and the Time-Of-Flight facility for Nuclear Data Measurements for ADS (n T OF N D A DS); European Research Programme for the Transmutation of High Level Nuclear Waste in an Accelerator Driven System (EUROTRANS-NUDATRA); and CANDIDE; Programmes for transnational access to experimental facilities in Europe: European Facilities for Nuclear Data Measurements (EFNUDAT); Neutron Data Measurements at IRMM (NUDAME); European facility for innovative reactor and transmutation neutron data (EUFRAT) (P.A.)

Tunable elastic parity-time symmetric structure based on the shunted piezoelectric materials

Science.gov (United States)

Hou, Zhilin; Assouar, Badreddine

2018-02-01

We theoretically and numerically report on the tunable elastic Parity-Time (PT) symmetric structure based on shunted piezoelectric units. We show that the elastic loss and gain can be archived in piezoelectric materials when they are shunted by external circuits containing positive and negative resistances. We present and discuss, as an example, the strongly dependent relationship between the exceptional points of a three-layered system and the impedance of their external shunted circuit. The achieved results evidence that the PT symmetric structures based on this proposed concept can actively be tuned without any change of their geometric configurations.

US Army Nuclear Burst Detection System (NBDS)

International Nuclear Information System (INIS)

Glaser, R.F.

1980-07-01

The Nuclear Burst Detection System (NBDS) was developed to meet the Army requirements of an unattended, automatic nuclear burst reporting system. It provides pertinent data for battlefield commanders on a timely basis with high reliability

Asymmetrical and symmetrical embedded Z-source inverters

DEFF Research Database (Denmark)

Gao, F.; Loh, P.C.; Li, D.

2011-01-01

ends, which indirectly translates to a lowering of overall system cost. These noted advantages are indeed appropriate for applications like photovoltaic and fuel cell energy harnessing, and have already been confirmed in simulation and experimentally using a laboratory-implemented inverter prototype.......This study presents two types of embedded Z-source inverters with each type further divided into asymmetrical and symmetrical realisations. Being different from their traditional counterparts, the presented inverters have their dc sources inserted within their X-shaped impedance networks so...

Quality assurance system in nuclear engineering

International Nuclear Information System (INIS)

Adams, H.W.; Hoensch, V.

1985-01-01

Due to the close connection between the German Atomic Energy Law and the nuclear control regulations, quality systems in nuclear engineering have taken on a special form. Quality assurance systems as a stipulated organisation of structure and procedure to assure quality have implications for the organisation of the electric supply company at the planning, erection and commissioning stage and for the organisation of the nuclear power station facility. To supervise the application and effectiveness of the stipulated organisation of structure and procedure internally and externally among contractors, special organisation units have been set up at the plant suppliers, manufactures, electric supply companies and nuclear power station facilities, which in the electric supply field go by the name of Quality Assurance Supervision. (orig.) [de

Approach for Establishing a National Nuclear Forensics System

International Nuclear Information System (INIS)

Kim, Jaekwang; Hyung, Sangcheol

2014-01-01

The increasing number could give rise to posing a potential threat to national infrastructure which is very vulnerable to radiological sabotage with the materials. International community has been emphasizing the importance of nuclear forensics through the Nuclear Security Summit process as a countermeasure against nuclear terrorism. Global Initiative to Combat Nuclear Terrorism(GICNT) and nuclear forensics International Technology Working Group(ITWG) suggest the establishment of national nuclear forensics system which has a law enforcement for forensic management and maintenance of nuclear forensics database including nuclear material and other radioactive materials. We suggest the legal and institutional system through this paper in an effort to set up a multi expert group and the nuclear forensics DB which can contribute to effective Core capabilities

Approach for Establishing a National Nuclear Forensics System

Energy Technology Data Exchange (ETDEWEB)

Kim, Jaekwang; Hyung, Sangcheol [Korea Institute of Nuclear Nonproliferation and Control, Daejeon (Korea, Republic of)

2014-05-15

The increasing number could give rise to posing a potential threat to national infrastructure which is very vulnerable to radiological sabotage with the materials. International community has been emphasizing the importance of nuclear forensics through the Nuclear Security Summit process as a countermeasure against nuclear terrorism. Global Initiative to Combat Nuclear Terrorism(GICNT) and nuclear forensics International Technology Working Group(ITWG) suggest the establishment of national nuclear forensics system which has a law enforcement for forensic management and maintenance of nuclear forensics database including nuclear material and other radioactive materials. We suggest the legal and institutional system through this paper in an effort to set up a multi expert group and the nuclear forensics DB which can contribute to effective Core capabilities.

Nuclear technology databases and information network systems

International Nuclear Information System (INIS)

Iwata, Shuichi; Kikuchi, Yasuyuki; Minakuchi, Satoshi

1993-01-01

This paper describes the databases related to nuclear (science) technology, and information network. Following contents are collected in this paper: the database developed by JAERI, ENERGY NET, ATOM NET, NUCLEN nuclear information database, INIS, NUclear Code Information Service (NUCLIS), Social Application of Nuclear Technology Accumulation project (SANTA), Nuclear Information Database/Communication System (NICS), reactor materials database, radiation effects database, NucNet European nuclear information database, reactor dismantling database. (J.P.N.)

Nuclear power systems: Their safety

International Nuclear Information System (INIS)

Myers, L.C.

1993-01-01

Mankind utilizes energy in many forms and from a variety of sources. Canada is one of a growing number of countries which have chosen to embrace nuclear-electric generation as a component of their energy systems. As of August 1992 there were 433 power reactors operating in 35 countries and accounting for more than 15% of the world's production of electricity. In 1992, thirteen countries derived at least 25% of their electricity from nuclear units, with France leading at nearly 70%. In the same year, Canada produced about 16% of its electricity from nuclear units. Some 68 power reactors are under construction in 16 countries, enough to expand present generating capacity by close to 20%. No human endeavour carries the guarantee of perfect safety and the question of whether or not nuclear-electric generation represents an 'acceptable' risk to society has long been vigorously debated. Until the events of late April 1986, nuclear safety had indeed been an issue for discussion, for some concern, but not for alarm. The accident at the Chernobyl reactor in the USSR has irrevocably changed all that. This disaster brought the matter of nuclear safety back into the public mind in a dramatic fashion. This paper discusses the issue of safety in complex energy systems and provides brief accounts of some of the most serious reactor accidents which have occurred to date. (author). 7 refs

Radon transformation on reductive symmetric spaces: support theorems

NARCIS (Netherlands)

Kuit, J.J.|info:eu-repo/dai/nl/313872589

2011-01-01

In this thesis we introduce a class of Radon transforms for reductive symmetric spaces, including the horospherical transforms, and study some of their properties. In particular we obtain a generalization of Helgason's support theorem for the horospherical transform on a Riemannian symmetric space.

Decomposition of a symmetric second-order tensor

Science.gov (United States)

Heras, José A.

2018-05-01

In the three-dimensional space there are different definitions for the dot and cross products of a vector with a second-order tensor. In this paper we show how these products can uniquely be defined for the case of symmetric tensors. We then decompose a symmetric second-order tensor into its ‘dot’ part, which involves the dot product, and the ‘cross’ part, which involves the cross product. For some physical applications, this decomposition can be interpreted as one in which the dot part identifies with the ‘parallel’ part of the tensor and the cross part identifies with the ‘perpendicular’ part. This decomposition of a symmetric second-order tensor may be suitable for undergraduate courses of vector calculus, mechanics and electrodynamics.

U.S. national nuclear material control and accounting system

International Nuclear Information System (INIS)

Taylor, S; Terentiev, V G

1998-01-01

Issues related to nuclear material control and accounting and illegal dealing in these materials were discussed at the April 19--20, 1996 Moscow summit meeting (G7 + Russia). The declaration from this meeting reaffirmed that governments are responsible for the safety of all nuclear materials in their possession and for the effectiveness of the national control and accounting system for these materials. The Russian delegation at this meeting stated that ''the creation of a nuclear materials accounting, control, and physical protection system has become a government priority''. Therefore, in order to create a government nuclear material control and accounting system for the Russian Federation, it is critical to study the structure, operating principles, and regulations supporting the control and accounting of nuclear materials in the national systems of nuclear powers. In particular, Russian specialists have a definite interest in learning about the National Nuclear Material Control and Accounting System of the US, which has been operating successfully as an automated system since 1968

Nuclear renaissance in Asia. Energy security and development of nuclear power generation system

International Nuclear Information System (INIS)

Nakasugi, Hideo

2009-01-01

The energy policy and strategy of development of nuclear power generation system of China, India and Korea are stated on the basis of use of light water reactors (LWRs). The conditions of power generation and introduction plans of nuclear energy of other Asian countries such as Vietnam, Thailand, Indonesia, Malaysia and Philippines are described. The power plant capacity of China increased from 50,500 MW in 2004, to 65,000 MW in 2005, and the target value is 40,000 MW of operating nuclear plants and 18,000 MW in building in 2020. China is lagging behind in peaceful use of nuclear energy technologies. A plan for the reform of nuclear industry and nuclear power generation projects of China are summarized. Total power plant capacity of India is 145,000 MW, but the nuclear plant capacity is 4,120 MW in 2008 and 63,000 MW of the target in 2032. Development of nuclear power, circumstance, and cooperation with other countries' industries are explained. 17,716 MW of nuclear power is in operation, 6,800 MW in building and 2,800 MW in the planning stage in Korea. History of development of national reactors and the subjects of development of the fourth generation reactor of Korea are stated. Management system of nuclear power plants in China, technical bases of nuclear power plants in China, development system of nuclear power generation in India, the conditions of power production of Korea in 2008, the capacity factor of Korea, Japan and world from 1998 to 2008, and comparison of nuclear industries in China, India and Korea are illustrated. (S.Y.)

Revisiting the Optical PT-Symmetric Dimer

Directory of Open Access Journals (Sweden)

José Delfino Huerta Morales

2016-08-01

Full Text Available Optics has proved a fertile ground for the experimental simulation of quantum mechanics. Most recently, optical realizations of PT -symmetric quantum mechanics have been shown, both theoretically and experimentally, opening the door to international efforts aiming at the design of practical optical devices exploiting this symmetry. Here, we focus on the optical PT -symmetric dimer, a two-waveguide coupler where the materials show symmetric effective gain and loss, and provide a review of the linear and nonlinear optical realizations from a symmetry-based point of view. We go beyond a simple review of the literature and show that the dimer is just the smallest of a class of planar N-waveguide couplers that are the optical realization of the Lorentz group in 2 + 1 dimensions. Furthermore, we provide a formulation to describe light propagation through waveguide couplers described by non-Hermitian mode coupling matrices based on a non-Hermitian generalization of the Ehrenfest theorem.

Heat transfer and fluid flow in nuclear systems

CERN Document Server

Fenech, Henri

1982-01-01

Heat Transfer and Fluid in Flow Nuclear Systems discusses topics that bridge the gap between the fundamental principles and the designed practices. The book is comprised of six chapters that cover analysis of the predicting thermal-hydraulics performance of large nuclear reactors and associated heat-exchangers or steam generators of various nuclear systems. Chapter 1 tackles the general considerations on thermal design and performance requirements of nuclear reactor cores. The second chapter deals with pressurized subcooled light water systems, and the third chapter covers boiling water reacto

Parity-Time Symmetric Photonics

KAUST Repository

Zhao, Han

2018-01-17

The establishment of non-Hermitian quantum mechanics (such as parity-time (PT) symmetry) stimulates a paradigmatic shift for studying symmetries of complex potentials. Owing to the convenient manipulation of optical gain and loss in analogy to the complex quantum potentials, photonics provides an ideal platform for visualization of many conceptually striking predictions from the non-Hermitian quantum theory. A rapidly developing field has emerged, namely, PT symmetric photonics, demonstrating intriguing optical phenomena including eigenstate coalescence and spontaneous PT symmetry breaking. The advance of quantum physics, as the feedback, provides photonics with brand-new paradigms to explore the entire complex permittivity plane for novel optical functionalities. Here, we review recent exciting breakthroughs in PT symmetric photonics while systematically presenting their underlying principles guided by non-Hermitian symmetries. The potential device applications for optical communication and computing, bio-chemical sensing, and healthcare are also discussed.

Nuclear criticality information system

International Nuclear Information System (INIS)

Koponen, B.L.; Hampel, V.E.

1981-01-01

The nuclear criticality safety program at LLNL began in the 1950's with a critical measurements program which produced benchmark data until the late 1960's. This same time period saw the rapid development of computer technology useful for both computer modeling of fissile systems and for computer-aided management and display of the computational benchmark data. Database management grew in importance as the amount of information increased and as experimental programs were terminated. Within the criticality safety program at LLNL we began at that time to develop a computer library of benchmark data for validation of computer codes and cross sections. As part of this effort, we prepared a computer-based bibliography of criticality measurements on relatively simple systems. However, it is only now that some of these computer-based resources can be made available to the nuclear criticality safety community at large. This technology transfer is being accomplished by the DOE Technology Information System (TIS), a dedicated, advanced information system. The NCIS database is described

Nuclear power reactors and hydrogen storage systems

International Nuclear Information System (INIS)

Ibrahim Aly Mahmoud El Osery.

1980-01-01

Among conclusions and results come by, a nuclear-electric-hydrogen integrated power system was suggested as a way to prevent the energy crisis. It was shown that the hydrogen power system using nuclear power as a leading energy resource would hold an advantage in the current international situation as well as for the long-term future. Results reported provide designers of integrated nuclear-electric-hydrogen systems with computation models and routines which will allow them to explore the optimal solution in coupling power reactors to hydrogen producing systems, taking into account the specific characters of hydrogen storage systems. The models were meant for average computers of a type easily available in developing countries. (author)

Advanced physical protection systems for nuclear materials

International Nuclear Information System (INIS)

Jones, O.E.

1976-01-01

Because of the increasing incidence of terrorism, there is growing concern that nuclear materials and facilities need improved physical protection against theft, diversion, or sabotage. Physical protection systems for facilities or transportation which have balanced effectiveness include information systems, access denial systems, adequate and timely response, recovery capability, and use denial methods for despoiling special nuclear materials (SNM). The role of these elements in reducing societal risk is described; however, it is noted that, similar to nuclear war, the absolute risks of nuclear theft and sabotage are basically unquantifiable. Sandia Laboratories has a major US Energy Research and Development Administration (ERDA) role in developing advanced physical protection systems for improving the security of both SNM and facilities. These activities are surveyed in this paper. A computer simulation model is being developed to assess the cost-effectiveness of alternative physical protection systems under various levels of threat. Improved physical protection equipment such as perimeter and interior alarms, secure portals, and fixed and remotely activated barriers is being developed and tested. In addition, complete prototype protection systems are being developed for representative nuclear facilities. An example is shown for a plutonium storage vault. The ERDA safe-secure transportation system for highway shipments of all significant quantities of government-owned SNM is described. Adversary simulation as a tool for testing and evaluating physical protection systems is discussed. Finally, a list of measures is given for assessing overall physical protection system performance. (author)

Advanced physical protection systems for nuclear materials

International Nuclear Information System (INIS)

Jones, O.E.

1975-10-01

Because of the increasing incidence of terrorism, there is growing concern that nuclear materials and facilities need improved physical protection against theft, diversion, or sabotage. Physical protection systems for facilities or transportation which have balanced effectiveness include information systems, access denial systems, adequate and timely response, recovery capability, and use denial methods for despoiling special nuclear materials (SNM). The role of these elements in reducing societal risk is described; however, it is noted that, similar to nuclear war, the absolute risks of nuclear theft and sabotage are basically unquantifiable. Sandia Laboratories has a major Energy Research and Development Administration (ERDA) role in developing advanced physical protection systems for improving the security of both SNM and facilities. These activities are surveyed. A computer simulation model is being developed to assess the cost-effectiveness of alternative physical protection systems under various levels of threat. Improved physical protection equipment such as perimeter and interior alarms, secure portals, and fixed and remotely-activated barriers is being developed and tested. In addition, complete prototype protection systems are being developed for representative nuclear facilities. An example is shown for a plutonium storage vault. The ERDA safe-secure transportation system for highway shipments of all significant quantities of government-owned SNM is described. Adversary simulation as a tool for testing and evaluating physical protection systems is discussed. A list of measures is given for assessing overall physical protection system performance. (auth)

Symmetric alignment of the nematic matrix between close penetrable colloidal particles

International Nuclear Information System (INIS)

Teixeira, P I C; Barmes, F; Cleaver, D J

2004-01-01

A simple model is proposed for the liquid crystal matrix surrounding 'soft' colloidal particles whose separation is much smaller than their radii. We use our implementation of the Onsager approximation of density-functional theory (Chrzanowska et al 2001 J. Phys.: Condens. Matter 13 4715) to calculate the structure of a nanometrically thin film of hard Gaussian overlap particles of elongations κ = 3 and 5, confined between two solid walls. The penetrability of either substrate can be tuned independently to yield symmetric or hybrid alignment. Comparison with Monte Carlo simulations of the same system (Cleaver and Teixeira 2001 Chem. Phys. Lett. 338 1, Barmes and Cleaver 2004 in preparation) reveals good agreement in the symmetric case

Crossing symmetric solution of the Chew-Low equation

International Nuclear Information System (INIS)

McLeod, R.J.; Ernst, D.J.

1982-01-01

An N/D dispersion theory is developed which solves crossing symmetric Low equations. The method is used to generate crossing symmetric solutions to the Chew-Low model. We show why the technique originally proposed by Chew and Low was incapable of producing solutions. (orig.)

Reliability of sprinkler systems. Exploration and analysis of data from nuclear and non-nuclear installations

International Nuclear Information System (INIS)

Roenty, V.; Keski-Rahkonen, O.; Hassinen, J.P.

2004-12-01

Sprinkler systems are an important part of fire safety of nuclear installations. As a part of effort to make fire-PSA of our utilities more quantitative a literature survey from open sources worldwide of available reliability data on sprinkler systems was carried out. Since the result of the survey was rather poor quantitatively, it was decided to mine available original Finnish nuclear and non-nuclear data, since nuclear power plants present a rather small device population. Sprinklers are becoming a key element for the fire safety in modern, open non-nuclear buildings. Therefore, the study included both nuclear power plants and non-nuclear buildings protected by sprinkler installations. Data needed for estimating of reliability of sprinkler systems were collected from available sources in Finnish nuclear and non-nuclear installations. Population sizes on sprinkler system installations and components therein as well as covered floor areas were counted individually from Finnish nuclear power plants. From non-nuclear installations corresponding data were estimated by counting relevant things from drawings of 102 buildings, and plotting from that sample needed probability distributions. The total populations of sprinkler systems and components were compiled based on available direct data and these distributions. From nuclear power plants electronic maintenance reports were obtained, observed failures and other reliability relevant data were selected, classified according to failure severity, and stored on spreadsheets for further analysis. A short summary of failures was made, which was hampered by a small sample size. From non-nuclear buildings inspection statistics from years 1985.1997 were surveyed, and observed failures were classified and stored on spreadsheets. Finally, a reliability model is proposed based on earlier formal work, and failure frequencies obtained by preliminary data analysis of this work. For a model utilising available information in the non-nuclear

Nuclear Fuel Cycle Information System. A directory of nuclear fuel cycle facilities. 2009 ed

International Nuclear Information System (INIS)

2009-04-01

The Nuclear Fuel Cycle Information System (NFCIS) is an international directory of civilian nuclear fuel cycle facilities, published online as part of the Integrated Nuclear Fuel Cycle Information System (iNFCIS: http://www-nfcis.iaea.org/). This is the fourth hardcopy publication in almost 30 years and it represents a snapshot of the NFCIS database as of the end of 2008. Together with the attached CD-ROM, it provides information on 650 civilian nuclear fuel cycle facilities in 53 countries, thus helping to improve the transparency of global nuclear fuel cycle activities

Space nuclear power systems for extraterrestrial basing

International Nuclear Information System (INIS)

Lance, J.R.; Chi, J.W.H.

1989-01-01

Previous studies of nuclear and non-nuclear power systems for lunar bases are compared with recent studies by others. Power levels from tens of kW e for early base operation up to 2000 kW e for a self-sustaining base with a Closed Environment Life Support System (CELSS) are considered. Permanent lunar or Martian bases will require the use of multiple nuclear units connected to loads with a power transmission and distribution system analogous to earth-based electric utility systems. A methodology used for such systems is applied to the lunar base system to examine the effects of adding 100 kW e SP-100 class and/or larger nuclear units when a reliability criterion is imposed. The results show that resource and logistic burdens can be reduced by using 1000 kW e units early in the base growth scenario without compromising system reliability. Therefore, both technologies being developed in two current programs (SP-100 and NERVA Derivative Reactor (NDR) technology for space power) can be used effectively for extraterrestrial base power systems. Recent developments in NDR design that result in major reductions in reactor mass are also described. (author)

Management review of nuclear material control and accounting systems

International Nuclear Information System (INIS)

1975-06-01

Section 70.58, ''Fundamental Nuclear Material Controls,'' of 10 CFR Part 70, ''Special Nuclear Materials,'' requires, in paragraph 70.58(c), that certain licensees authorized to possess more than one effective kilogram of special nuclear material establish a management system to provide for the development, revision, implementation, and enforcement of nuclear material control and accounting procedures. Such a system must provide for a review of the nuclear material control system at least every 12 months. This guide describes the purpose and scope, personnel qualifications, depth of detail, and procedures that are acceptable to the NRC staff for the management review of nuclear material control systems required under paragraph 70.58(c) of 10 CFR Part 70. (U.S.)

A possible method for non-Hermitian and Non-PT-symmetric Hamiltonian systems.

Directory of Open Access Journals (Sweden)

Jun-Qing Li

Full Text Available A possible method to investigate non-Hermitian Hamiltonians is suggested through finding a Hermitian operator η+ and defining the annihilation and creation operators to be η+ -pseudo-Hermitian adjoint to each other. The operator η+ represents the η+ -pseudo-Hermiticity of Hamiltonians. As an example, a non-Hermitian and non-PT-symmetric Hamiltonian with imaginary linear coordinate and linear momentum terms is constructed and analyzed in detail. The operator η+ is found, based on which, a real spectrum and a positive-definite inner product, together with the probability explanation of wave functions, the orthogonality of eigenstates, and the unitarity of time evolution, are obtained for the non-Hermitian and non-PT-symmetric Hamiltonian. Moreover, this Hamiltonian turns out to be coupled when it is extended to the canonical noncommutative space with noncommutative spatial coordinate operators and noncommutative momentum operators as well. Our method is applicable to the coupled Hamiltonian. Then the first and second order noncommutative corrections of energy levels are calculated, and in particular the reality of energy spectra, the positive-definiteness of inner products, and the related properties (the probability explanation of wave functions, the orthogonality of eigenstates, and the unitarity of time evolution are found not to be altered by the noncommutativity.

Nuclear fuel cycle simulation system (VISTA)

International Nuclear Information System (INIS)

2007-02-01

The Nuclear Fuel Cycle Simulation System (VISTA) is a simulation system which estimates long term nuclear fuel cycle material and service requirements as well as the material arising from the operation of nuclear fuel cycle facilities and nuclear power reactors. The VISTA model needs isotopic composition of spent nuclear fuel in order to make estimations of the material arisings from the nuclear reactor operation. For this purpose, in accordance with the requirements of the VISTA code, a new module called Calculating Actinide Inventory (CAIN) was developed. CAIN is a simple fuel depletion model which requires a small number of input parameters and gives results in a very short time. VISTA has been used internally by the IAEA for the estimation of: spent fuel discharge from the reactors worldwide, Pu accumulation in the discharged spent fuel, minor actinides (MA) accumulation in the spent fuel, and in the high level waste (HLW) since its development. The IAEA decided to disseminate the VISTA tool to Member States using internet capabilities in 2003. The improvement and expansion of the simulation code and the development of the internet version was started in 2004. A website was developed to introduce the simulation system to the visitors providing a simple nuclear material flow calculation tool. This website has been made available to Member States in 2005. The development work for the full internet version is expected to be fully available to the interested parties from IAEA Member States in 2007 on its website. This publication is the accompanying text which gives details of the modelling and an example scenario

Entanglement of polar symmetric top molecules as candidate qubits.

Science.gov (United States)

Wei, Qi; Kais, Sabre; Friedrich, Bretislav; Herschbach, Dudley

2011-10-21

Proposals for quantum computing using rotational states of polar molecules as qubits have previously considered only diatomic molecules. For these the Stark effect is second-order, so a sizable external electric field is required to produce the requisite dipole moments in the laboratory frame. Here we consider use of polar symmetric top molecules. These offer advantages resulting from a first-order Stark effect, which renders the effective dipole moments nearly independent of the field strength. That permits use of much lower external field strengths for addressing sites. Moreover, for a particular choice of qubits, the electric dipole interactions become isomorphous with NMR systems for which many techniques enhancing logic gate operations have been developed. Also inviting is the wider chemical scope, since many symmetric top organic molecules provide options for auxiliary storage qubits in spin and hyperfine structure or in internal rotation states. © 2011 American Institute of Physics

A philosophy for space nuclear systems safety

International Nuclear Information System (INIS)

Marshall, A.C.

1992-01-01

The unique requirements and contraints of space nuclear systems require careful consideration in the development of a safety policy. The Nuclear Safety Policy Working Group (NSPWG) for the Space Exploration Initiative has proposed a hierarchical approach with safety policy at the top of the hierarchy. This policy allows safety requirements to be tailored to specific applications while still providing reassurance to regulators and the general public that the necessary measures have been taken to assure safe application of space nuclear systems. The safety policy used by the NSPWG is recommended for all space nuclear programs and missions

Nuclear excited power generation system

International Nuclear Information System (INIS)

Parker, R.Z.; Cox, J.D.

1989-01-01

A power generation system is described, comprising: a gaseous core nuclear reactor; means for passing helium through the reactor, the helium being excited and forming alpha particles by high frequency radiation from the core of the gaseous core nuclear reactor; a reaction chamber; means for coupling chlorine and hydrogen to the reaction chamber, the helium and alpha particles energizing the chlorine and hydrogen to form a high temperature, high pressure hydrogen chloride plasma; means for converting the plasma to electromechanical energy; means for coupling the helium back to the gaseous core nuclear reactor; and means for disassociating the hydrogen chloride to form molecular hydrogen and chlorine, to be coupled back to the reaction chamber in a closed loop. The patent also describes a power generation system comprising: a gaseous core nuclear reactor; means for passing hydrogen through the reactor, the hydrogen being excited by high frequency radiation from the core; means for coupling chlorine to a reaction chamber, the hydrogen energizing the chlorine in the chamber to form a high temperature, high pressure hydrogen chloride plasma; means for converting the plasma to electromechanical energy; means for disassociating the hydrogen chloride to form molecular hydrogen and chlorine, and means for coupling the hydrogen back to the gaseous core nuclear reactor in a closed loop

Nuclear energy in Canada: the CANDU system

International Nuclear Information System (INIS)

Robertson, J.A.L.

1979-10-01

Nuclear electricity in Canada is generated by CANDU nuclear power stations. The CANDU reactor - a unique Canadian design - is fuelled by natural uranium and moderated by heavy water. The system has consistently outperformed other comparable nuclear power systems in the western world, and has an outstanding record of reliability, safety and economy. As a source of energy it provides the opportunity for decreasing our dependence on dwindling supplies of conventional fossil fuels. (auth)

Chaos control and generalized projective synchronization of heavy symmetric chaotic gyroscope systems via Gaussian radial basis adaptive variable structure control

International Nuclear Information System (INIS)

Farivar, Faezeh; Aliyari Shoorehdeli, Mahdi; Nekoui, Mohammad Ali; Teshnehlab, Mohammad

2012-01-01

Highlights: ► A systematic procedure for GPS of unknown heavy chaotic gyroscope systems. ► Proposed methods are based on Lyapunov stability theory. ► Without calculating Lyapunov exponents and Eigen values of the Jacobian matrix. ► Capable to extend for a variety of chaotic systems. ► Useful for practical applications in the future. - Abstract: This paper proposes the chaos control and the generalized projective synchronization methods for heavy symmetric gyroscope systems via Gaussian radial basis adaptive variable structure control. Because of the nonlinear terms of the gyroscope system, the system exhibits chaotic motions. Occasionally, the extreme sensitivity to initial states in a system operating in chaotic mode can be very destructive to the system because of unpredictable behavior. In order to improve the performance of a dynamic system or avoid the chaotic phenomena, it is necessary to control a chaotic system with a periodic motion beneficial for working with a particular condition. As chaotic signals are usually broadband and noise like, synchronized chaotic systems can be used as cipher generators for secure communication. This paper presents chaos synchronization of two identical chaotic motions of symmetric gyroscopes. In this paper, the switching surfaces are adopted to ensure the stability of the error dynamics in variable structure control. Using the neural variable structure control technique, control laws are established which guarantees the chaos control and the generalized projective synchronization of unknown gyroscope systems. In the neural variable structure control, Gaussian radial basis functions are utilized to on-line estimate the system dynamic functions. Also, the adaptation laws of the on-line estimator are derived in the sense of Lyapunov function. Thus, the unknown gyro systems can be guaranteed to be asymptotically stable. Also, the proposed method can achieve the control objectives. Numerical simulations are presented to

Symmetric webs, Jones-Wenzl recursions and q-Howe duality

DEFF Research Database (Denmark)

Rose, David; Tubbenhauer, Daniel

We define and study the category of symmetric sl2-webs. This category is a combinatorial description of the category of all finite dimensional quantum sl2-modules. Explicitly, we show that (the additive closure of) the symmetric sl2-spider is (braided monoidally) equivalent to the latter. Our mai...... tool is a quantum version of symmetric Howe duality. As a corollary of our construction, we provide new insight into Jones-Wenzl projectors and the colored Jones polynomials....

Computer systems and nuclear industry

International Nuclear Information System (INIS)

Nkaoua, Th.; Poizat, F.; Augueres, M.J.

1999-01-01

This article deals with computer systems in nuclear industry. In most nuclear facilities it is necessary to handle a great deal of data and of actions in order to help plant operator to drive, to control physical processes and to assure the safety. The designing of reactors requires reliable computer codes able to simulate neutronic or mechanical or thermo-hydraulic behaviours. Calculations and simulations play an important role in safety analysis. In each of these domains, computer systems have progressively appeared as efficient tools to challenge and master complexity. (A.C.)

Multifragment disintegrations of expanding nuclear systems

International Nuclear Information System (INIS)

Gelbke, K.

1993-01-01

Two phase transitions are expected to exist in bulk nuclear matter: a liquid-gas phase transition and a deconfinement transition to a quark-gluon plasma. In studies of nucleus-nucleus collisions, conditions similar to those pertaining to phase transitions in infinite systems can be created, but the fundamental problem yet to be solved is the identification of remnant signatures uniquely related to either of these phase transitions. Nuclear systems at densities and temperatures corresponding to the liquid-gas coexistence region can be produced in intermediate energy nucleus-nucleus collisions; they are expected to decay into many intermediate mass fragments (IMF's: Z=3-20). Recent investigations with low-threshold electronic 4π detector arrays have firmly established the occurrence of multifragment disintegrations of hot nuclear systems and allowed to challenge various theoretical approaches. In this talk, an overview of pertinent experimental results on multifragmentation will be presented and discussed. it will be shown that current microscopic transport theories designed to treat the growth of density fluctuations predict fragment multiplicities much smaller than observed experimentally. Measurements of the time scales of fragment formation are consistent with statistical model calculations for expanding hot nuclear system which indicate that fragments may form during a rather narrow time interval after the system has cooled and expanded to a density below that of normal nuclear matter. The expansion rate (and hence the fragment multiplicity) is sensitive to the equation of state (EOS). However, a number of recent results provide increasing evidence that current theoretical treatments need to be refined to allow an experimental determination of the EOS

Nuclear plant-aging research on reactor protection systems

International Nuclear Information System (INIS)

Meyer, L.C.

1988-01-01

This report presents the rsults of a review of the Reactor Trip System (RTS) and the Engineered Safety Feature Actuating System (ESFAS) operating experiences reported in Licensee Event Reports (LER)s, the Nuclear Power Experience data base, Nuclear Plant Reliability Data System, and plant maintenance records. Our purpose is to evaluate the potential significance of aging, including cycling, trips, and testing as contributors to degradation of the RTS and ESFAS. Tables are presented that show the percentage of events for RTS and ESFAS classified by cause, components, and subcomponents for each of the Nuclear Steam Supply System vendors. A representative Babcock and Wilcox plant was selected for detailed study. The US Nuclear Regulatory Commission's Nuclear Plant Aging Research guidelines were followed in performing the detailed study that identified materials susceptible to aging, stressors, environmental factors, and failure modes for the RTS and ESFAS as generic instrumentation and control systems. Functional indicators of degradation are listed, testing requirements evaluated, and regulatory issues discussed

SUSY formalism for the symmetric double well potential

Indian Academy of Sciences (India)

symmetric double well potential barrier we have obtained a class of exactly solvable potentials subject to moving boundary condition. The eigenstates are also obtained by the same technique. Keywords. SUSY; moving boundary condition; exactly solvable; symmetric double well; NH3 molecule. PACS Nos 02.30.Ik; 03.50.

Coupled dilaton and electromagnetic field in cylindrically symmetric ...

Indian Academy of Sciences (India)

The dilaton black hole solutions have attracted considerable attention for the ... theory and study the corresponding cylindrically symmetric spacetime, where .... where Йm and Йe are integration constants to be interpreted later as the ..... feature is apparent for the cylindrically symmetric spacetime in the presence of the dila-.

A new option for exploitage of future nuclear energy. Accelerator driven radioactive clean nuclear power system

International Nuclear Information System (INIS)

Ding Dazhao

2000-01-01

Nuclear energy is an effective, clean and safe energy resource. But some shortages of the nuclear energy system presently commercial available obstruct further development of the nuclear energy by heavy nuclear fission. Those are final disposal of the high level radioactive waste, inefficient use of the uranium resource and safety issue of the system. Innovative technical option is seeking for by the nuclear scientific community in recent ten years in aiming to overcome these obstacles, namely, accelerator driven sub-critical system (ADS). This hybrid system may bridge over the gap between presently commercial available nuclear power system and the full exploitation of the fusion energy. The basic principle of ADS is described and its capability in waste transmutation, conversion of the nuclear fuel are demonstrated by two examples--AD-fast reactor and AD-heavy water thermal reactor. The feasibility of ADS and some projects in US, Japan, etc are briefly discussed. The rationale in promoting the R and D of ADS in China is emphasized as China is at the beginning stage of its ambitious project in construction of the nuclear power

Nuclear Material Control and Accountability System Effectiveness Tool (MSET)

International Nuclear Information System (INIS)

Powell, Danny H.; Elwood, Robert H. Jr.; Roche, Charles T.; Campbell, Billy J.; Hammond, Glenn A.; Meppen, Bruce W.; Brown, Richard F.

2011-01-01

A nuclear material control and accountability (MC and A) system effectiveness tool (MSET) has been developed in the United States for use in evaluating material protection, control, and accountability (MPC and A) systems in nuclear facilities. The project was commissioned by the National Nuclear Security Administration's Office of International Material Protection and Cooperation. MSET was developed by personnel with experience spanning more than six decades in both the U.S. and international nuclear programs and with experience in probabilistic risk assessment (PRA) in the nuclear power industry. MSET offers significant potential benefits for improving nuclear safeguards and security in any nation with a nuclear program. MSET provides a design basis for developing an MC and A system at a nuclear facility that functions to protect against insider theft or diversion of nuclear materials. MSET analyzes the system and identifies several risk importance factors that show where sustainability is essential for optimal performance and where performance degradation has the greatest impact on total system risk. MSET contains five major components: (1) A functional model that shows how to design, build, implement, and operate a robust nuclear MC and A system (2) A fault tree of the operating MC and A system that adapts PRA methodology to analyze system effectiveness and give a relative risk of failure assessment of the system (3) A questionnaire used to document the facility's current MPC and A system (provides data to evaluate the quality of the system and the level of performance of each basic task performed throughout the material balance area (MBA)) (4) A formal process of applying expert judgment to convert the facility questionnaire data into numeric values representing the performance level of each basic event for use in the fault tree risk assessment calculations (5) PRA software that performs the fault tree risk assessment calculations and produces risk importance

Expert systems and nuclear safety

International Nuclear Information System (INIS)

Beltracchi, L.

1990-01-01

The US Nuclear Regulatory Commission (NRC) and the Electric Power Research Institute have initiated a broad-based exploration of means to evaluate the potential applications of expert systems in the nuclear industry. This exploratory effort will assess the use of expert systems to augment the diagnostic and decision-making capabilities of personnel with the goal of enhancing productivity, reliability, and performance. The initial research effort is the development and documentation of guidelines for verifying and validating (V and V) expert systems. An initial application of expert systems in the nuclear industry is to aid operations and maintenance personnel in decision-making tasks. The scope of the decision aiding covers all types of cognitive behavior consisting of skill, rule, and knowledge-based behavior. For example, procedure trackers were designed and tested to support rule-based behavior. Further, these systems automate many of the tedious, error-prone human monitoring tasks, thereby reducing the potential for human error. The paper version of the procedure contains the knowledge base and the rules and thus serves as the basis of the design verification of the procedure tracker. Person-in-the-loop tests serve as the basis for the validation of a procedure tracker. When conducting validation tests, it is important to ascertain that the human retains the locus of control in the use of the expert system

Public concerns and alternative nuclear power systems

International Nuclear Information System (INIS)

Mayo, L.H.

1980-02-01

The basic task undertaken in this study was to assess the relative public acceptability of three general types of nuclear power systems as alternatives to the existing Light Water Reactor (LWR) system. Concerns registered toward nuclear power constituted the basic data for this assessment. The primary measure adopted for determining the significance of concerns was the degree of difficulty posed by the concern to the nuclear power decisional structure in the establishment and maintenance of norms to control risks or to advance intended energy objectives. Alleviations or exacerbations of concern resulting from particular attributes of alternative systems were measured from an LWR baseline

NCIS - a Nuclear Criticality Information System (overview)

International Nuclear Information System (INIS)

Koponen, B.L.; Hampel, V.E.

1983-07-01

A Nuclear Criticality Information System (NCIS) is being established at the Lawrence Livermore National Laboratory (LLNL) in order to serve personnel responsible for safe storage, transport, and handling of fissile materials and those concerned with the evaluation and analysis of nuclear, critical experiments. Public concern for nuclear safety provides the incentive for improved access to nuclear safety information

Structural materials for innovative nuclear systems (SMINS)

International Nuclear Information System (INIS)

2008-01-01

Structural materials research is a field of growing relevance in the nuclear sector, especially for the different innovative reactor systems being developed within the Generation IV International Forum (GIF), for critical and subcritical transmutation systems, and of interest to the Global Nuclear Energy Partnership (GNEP). Under the auspices of the NEA Nuclear Science Committee (NSC) the Workshop on Structural Materials for Innovative Nuclear Systems (SMINS) was organised in collaboration with the Forschungszentrum Karlsruhe in Germany. The objectives of the workshop were to exchange information on structural materials research issues and to discuss ongoing programmes, both experimental and in the field of advanced modelling. These proceedings include the papers and the poster session materials presented at the workshop, representing the international state of the art in this domain. (author)

Generalized Weyl–Heisenberg Algebra, Qudit Systems and Entanglement Measure of Symmetric States via Spin Coherent States

Directory of Open Access Journals (Sweden)

Mohammed Daoud

2018-04-01

Full Text Available A relation is established in the present paper between Dicke states in a d-dimensional space and vectors in the representation space of a generalized Weyl–Heisenberg algebra of finite dimension d. This provides a natural way to deal with the separable and entangled states of a system of N = d − 1 symmetric qubit states. Using the decomposition property of Dicke states, it is shown that the separable states coincide with the Perelomov coherent states associated with the generalized Weyl–Heisenberg algebra considered in this paper. In the so-called Majorana scheme, the qudit (d-level states are represented by N points on the Bloch sphere; roughly speaking, it can be said that a qudit (in a d-dimensional space is describable by a N-qubit vector (in a N-dimensional space. In such a scheme, the permanent of the matrix describing the overlap between the N qubits makes it possible to measure the entanglement between the N qubits forming the qudit. This is confirmed by a Fubini–Study metric analysis. A new parameter, proportional to the permanent and called perma-concurrence, is introduced for characterizing the entanglement of a symmetric qudit arising from N qubits. For d = 3 ( ⇔ N = 2 , this parameter constitutes an alternative to the concurrence for two qubits. Other examples are given for d = 4 and 5. A connection between Majorana stars and zeros of a Bargmmann function for qudits closes this article.

Nuclear Hybrid Energy Systems FY16 Modeling Efforts at ORNL

Energy Technology Data Exchange (ETDEWEB)

Cetiner, Sacit M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Greenwood, Michael Scott [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Harrison, Thomas J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Qualls, A. L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Guler Yigitoglu, Askin [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Fugate, David W. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

2016-09-01

A nuclear hybrid system uses a nuclear reactor as the basic power generation unit. The power generated by the nuclear reactor is utilized by one or more power customers as either thermal power, electrical power, or both. In general, a nuclear hybrid system will couple the nuclear reactor to at least one thermal power user in addition to the power conversion system. The definition and architecture of a particular nuclear hybrid system is flexible depending on local markets needs and opportunities. For example, locations in need of potable water may be best served by coupling a desalination plant to the nuclear system. Similarly, an area near oil refineries may have a need for emission-free hydrogen production. A nuclear hybrid system expands the nuclear power plant from its more familiar central power station role by diversifying its immediately and directly connected customer base. The definition, design, analysis, and optimization work currently performed with respect to the nuclear hybrid systems represents the work of three national laboratories. Idaho National Laboratory (INL) is the lead lab working with Argonne National Laboratory (ANL) and Oak Ridge National Laboratory. Each laboratory is providing modeling and simulation expertise for the integration of the hybrid system.

The protection system to Brazilian Nuclear Program; O sistema de protecao ao Programa Nuclear Brasileiro

Energy Technology Data Exchange (ETDEWEB)

Andreuzza, Mario Giussepp Santezzi Bertottelli [Secretaria de Assuntos Estrategicos (SAE), Brasilia, DF (Brazil)

1997-12-31

The Sistema de Protecao ao Programa Nuclear Brasileiro-SIPRON (Protection System to Brazilian Nuclear Program) was established in 1980. It is intended to accomplish in only one system, all the actions related to security and protection for Nuclear Facilities in Brazil. The author presents in detail the protection system SIPRON, describing the system structure and organization, the functions and obligations of the system involved main organizations, as well as, the system operation and behaviour during an postulated occurrence of a nuclear emergency. It is also described an Exercise that happened in June of 1997 at the Nuclear Power Plant (NPP) Angra I, after two simulated tests in December of 1996 and April of 1997. The NPP Angra I Emergency Plan Exercise was a good opportunity to test the SIPRON structure and preparedness program. It was verified, included by International Atomic Energy Agency observers, the system involved organizations effectiveness and the procedures efficacy to protect the public and the environmental. Finally, it is shown the SIPRON activities of routine, the system obstacles and the expected future performances. (author) 3 refs., 3 figs.

Nuclear systems of level measurement

International Nuclear Information System (INIS)

Lara, A.J.; Cabrera, M.J.

1992-01-01

In the industry there are processes in which is necessary to maintain the products level controlled which are handled for their transformation. The majority of such processes and by the operation conditions, they do not admit measure systems of level of invasive type then the application of nuclear techniques for level measurement results a big aid in these cases, since all the system installation is situated beyond frontiers of vessels that contain the product for measuring. In the Department of Nuclear Technology Applications of Mexican Petroleum Institute was developed a level measurement system by gamma rays transmission which operates in the Low Density Polyethylene plant of Petrochemical Complex Escolin at Poza Rica, Veracruz, Mexico. (Author)

Remote system for counting of nuclear pulses; Sistema remoto de conteo de pulsos nucleares

Energy Technology Data Exchange (ETDEWEB)

Nieves V, J.A.; Garcia H, J.M.; Aguilar B, M.A. [Instituto Nacional de Investigaciones Nucleares, Ingenieria Electronica, A.P. 18-1027, 11801 Mexico D.F. (Mexico)

1999-07-01

In this work, it is describe technically the remote system for counting of nuclear pulses, an integral system of the project radiological monitoring in a petroleum distillation tower. The system acquires the counting of incident nuclear particles in a nuclear detector which process this information and send it in serial form, using the RS-485 toward a remote receiver, which can be a Personal computer or any other device capable to interpret the communication protocol. (Author)

Nuclear instrumentation for the industrial measuring systems

International Nuclear Information System (INIS)

Normand, S.

2010-01-01

This work deals with nuclear instrumentation and its application to industry, power plant fuel reprocessing plant and finally with homeland security. The first part concerns the reactor instrumentation, in-core and ex-core measurement system. Ionization Uranium fission chamber will be introduced with their acquisition system especially Campbell mode system. Some progress have been done on regarding sensors failure foresee. The second part of this work deals with reprocessing plant and associated instrumentation for nuclear waste management. Proportional counters techniques will be discussed, especially Helium-3 counter, and new development on electronic concept for reprocessing nuclear waste plant (one electronic for multipurpose acquisition system). For nuclear safety and security for human and homeland will be introduce. First we will explain a new particular approach on operational dosimetric measurement and secondly, we will show new kind of organic scintillator material and associated electronics. Signal treatment with real time treatment is embedded, in order to make neutron gamma discrimination possible even in solid organic scintillator. Finally, the conclusion will point out future, with most trends in research and development on nuclear instrumentation for next years. (author) [fr

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.

Emerging nuclear energy systems: Economic challenge: Revision 1

International Nuclear Information System (INIS)

Nuckolls, J.H.

1986-01-01

Future nuclear energy systems may achieve substantially lower energy costs than those of existing fossil energy systems and comparable capital costs. Such low cost nuclear energy would provide a strong economic incentive to minimize the use of fossil fuels. If these low cost nuclear energy systems emerge in the next few decades, 21st century civilization may be able to avert potentially disastrous CO 2 induced global climate changes. 12 refs., 1 fig

A future vision of nuclear material information systems

International Nuclear Information System (INIS)

Suski, N.; Wimple, C.

1999-01-01

To address the current and future needs for nuclear materials management and safeguards information, Lawrence Livermore National Laboratory envisions an integrated nuclear information system that will support several functions. The vision is to link distributed information systems via a common communications infrastructure designed to address the information interdependencies between two major elements: Domestic, with information about specific nuclear materials and their properties, and International, with information pertaining to foreign nuclear materials, facility design and operations. The communication infrastructure will enable data consistency, validation and reconciliation, as well as provide a common access point and user interface for a broad range of nuclear materials information. Information may be transmitted to, from, and within the system by a variety of linkage mechanisms, including the Internet. Strict access control will be employed as well as data encryption and user authentication to provide the necessary information assurance. The system can provide a mechanism not only for data storage and retrieval, but will eventually provide the analytical tools necessary to support the U.S. government's nuclear materials management needs and non-proliferation policy goals

Simplifying numerical ray tracing for two-dimensional non circularly symmetric models of the human eye.

Science.gov (United States)

Jesus, Danilo A; Iskander, D Robert

2015-12-01

Ray tracing is a powerful technique to understand the light behavior through an intricate optical system such as that of a human eye. The prediction of visual acuity can be achieved through characteristics of an optical system such as the geometrical point spread function. In general, its precision depends on the number of discrete rays and the accurate surface representation of each eye's components. Recently, a method that simplifies calculation of the geometrical point spread function has been proposed for circularly symmetric systems [Appl. Opt.53, 4784 (2014)]. An extension of this method to 2D noncircularly symmetric systems is proposed. In this method, a two-dimensional ray tracing procedure for an arbitrary number of surfaces and arbitrary surface shapes has been developed where surfaces, rays, and refractive indices are all represented in functional forms being approximated by Chebyshev polynomials. The Liou and Brennan anatomically accurate eye model has been adapted and used for evaluating the method. Further, real measurements of the anterior corneal surface of normal, astigmatic, and keratoconic eyes were substituted for the first surface in the model. The results have shown that performing ray tracing, utilizing the two-dimensional Chebyshev function approximation, is possible for noncircularly symmetric models, and that such calculation can be performed with a newly created Chebfun toolbox.

Cylindrically symmetric Fresnel lens for high concentration photovoltaic

Science.gov (United States)

Hung, Yu-Ting; Su, Guo-Dung

2009-08-01

High concentration photovoltaic (HCPV) utilizes point-focus cost-effective plastic Fresnel lens. And a millimeter-sized Ill-V compound multi-junction solar cell is placed underneath focusing optics which can achieve cell efficiency potential of up to 40.7 %. The advantage of HCPV makes less solar cell area and higher efficiency; however, the acceptance angle of HCPV is about +/-1°, which is very small and the mechanical tracking of the sun is necessary. In order to reduce the power consumption and the angle tracking error of tracking systems, a light collector model with larger acceptance angle is designed with ZEMAX®. In this model, the original radially symmetric Fresnel lens of HCPV is replaced by cylindrically symmetric Fresnel lens and a parabolic reflective surface. Light is collected in two dimensions separately. And a couple of lenses and a light pipe are added before the solar cell chip in order to collect more light when sun light deviates from incident angle of 00. An acceptance angle of +/-10° is achieved with GCR 400.

Covariant, chirally symmetric, confining model of mesons

International Nuclear Information System (INIS)

Gross, F.; Milana, J.

1991-01-01

We introduce a new model of mesons as quark-antiquark bound states. The model is covariant, confining, and chirally symmetric. Our equations give an analytic solution for a zero-mass pseudoscalar bound state in the case of exact chiral symmetry, and also reduce to the familiar, highly successful nonrelativistic linear potential models in the limit of heavy-quark mass and lightly bound systems. In this fashion we are constructing a unified description of all the mesons from the π through the Υ. Numerical solutions for other cases are also presented

A study on LAN applications in nuclear safety systems

International Nuclear Information System (INIS)

Kim, Sung; Lee, Young Ryul; Koo, Jun Mo; Han, Jai Bok

1995-01-01

It is a general tendency to digitalize the conventional relay based I and C systems in nuclear power plant. But, the digitalisation of nuclear safety systems has many a difficulty to surmount. The typical one thing of many difficulties is the data communication problem between local controllers and systems. The network architecture built with LAN (Local Area Network) in digital systems of the other industries are general. But in case of nuclear safety systems many considerations in point of safety and license are required to implement it in the field. In this parer, some considerations for applying LAN in nuclear safety systems were reviewed

Nuclear engine system simulation (NESS) program update

International Nuclear Information System (INIS)

Scheil, C.M.; Pelaccio, D.G.; Petrosky, L.J.

1993-01-01

The second phase of development of a Nuclear Thermal Propulsion (NTP) engine system design analysis code has been completed. The standalone, versatile Nuclear Engine System Simulation (NESS) code provides an accurate, detailed assessment of engine system operating performance, weight, and sizes. The critical information is required to support ongoing and future engine system and stage design study efforts. This recent development effort included incorporation of an updated solid-core nuclear thermal reactor model that yields a reduced core weight and higher fuel power density when compared to a NERVA type reactor. NESS can now analyze expander, gas generator, and bleed cycles, along with multi-redundant propellant pump feed systems. Performance and weight of efficient multi-stage axial turbopump can now be determined, in addition to the traditional centrifugal pump

On the use of the Kodama vector field in spherically symmetric dynamical problems

Energy Technology Data Exchange (ETDEWEB)

Racz, Istvan [MTA KFKI, Reszecske- es Magfizikai Kutatointezet, H-1121 Budapest, Konkoly Thege Miklos ut 29-33, (Hungary)

2006-01-07

It is shown that by making use of the Kodama vector field, as a preferred time evolution vector field, in spherically symmetric dynamical systems unexpected simplifications arise. In particular, the evolution equations relevant for the case of a massless scalar field minimally coupled to gravity are investigated. The simplest form of these equations in the 'canonical gauge' is known to possess the character of a mixed first-order elliptic-hyperbolic system. The advantages related to the use of the Kodama vector field are twofold although they show up simultaneously. First, it is found that the true degrees of freedom separate. Second, a subset of the field equations possessing the form of a first-order symmetric hyperbolic system for these preferred degrees of freedom is singled out. It is also demonstrated, in the appendix, that the above results generalize straightforwardly to the case of a generic self-interacting scalar field.

Bistable states of TM polarized non-linear waves guided by symmetric layered structures

International Nuclear Information System (INIS)

Mihalache, D.

1985-04-01

Dispersion relations for TM polarized non-linear waves propagating in a symmetric single film optical waveguide are derived. The system consists of a layer of thickness d with dielectric constant epsilon 1 bounded at two sides by a non-linear medium characterized by the diagonal dielectric tensor epsilon 11 =epsilon 22 =epsilon 0 , epsilon 33 =epsilon 0 +α|E 3 | 2 , where E 3 is the normal electric field component. For sufficiently large d/lambda (lambda is the wavelength) we predict bistable states of both symmetric and antisymmetric modes provided that the power flow is the control parameter. (author)

Highly-dispersive electromagnetic induced transparency in planar symmetric metamaterials.

Science.gov (United States)

Lu, Xiqun; Shi, Jinhui; Liu, Ran; Guan, Chunying

2012-07-30

We propose, design and experimentally demonstrate highly-dispersive electromagnetically induced transparency (EIT) in planar symmetric metamaterials actively switched and controlled by angles of incidence. Full-wave simulation and measurement results show EIT phenomena, trapped-mode excitations and the associated local field enhancement of two symmetric metamaterials consisting of symmetrically split rings (SSR) and a fishscale (FS) metamaterial pattern, respectively, strongly depend on angles of incidence. The FS metamaterial shows much broader spectral splitting than the SSR metamaterial due to the surface current distribution variation.

A nuclear power plant system engineering workstation

International Nuclear Information System (INIS)

Mason, J.H.; Crosby, J.W.

1989-01-01

System engineers offer an approach for effective technical support for operation and maintenance of nuclear power plants. System engineer groups are being set up by most utilities in the United States. Institute of Nuclear Power operations (INPO) and U.S. Nuclear Regulatory Commission (NRC) have endorsed the concept. The INPO Good Practice and a survey of system engineer programs in the southeastern United States provide descriptions of system engineering programs. The purpose of this paper is to describe a process for developing a design for a department-level information network of workstations for system engineering groups. The process includes the following: (1) application of a formal information engineering methodology, (2) analysis of system engineer functions and activities; (3) use of Electric Power Research Institute (EPRI) Plant Information Network (PIN) data; (4) application of the Information Engineering Workbench. The resulting design for this system engineer workstation can provide a reference for design of plant-specific systems

Integrated Nuclear-Renewable Energy Systems: Foundational Workshop Report

International Nuclear Information System (INIS)

2014-01-01

The U.S. Department of Energy (DOE) recognizes the need to transform the energy infrastructure of the U.S. and elsewhere to systems that can drastically reduce environmental impacts in an efficient and economically viable manner while utilizing both hydrocarbon resources and clean energy generation sources. Thus, DOE is supporting research and development that could lead to more efficient utilization of clean energy generation sources, including renewable and nuclear options. A concept being advanced by the DOE Offices of Nuclear Energy (NE) and Energy Efficiency and Renewable Energy (EERE) is tighter coupling of nuclear and renewable energy sources in a manner that produces new energy currency for the combined electricity grid, industrial manufacturing, and the transportation energy sectors. This integration concept has been referred to as a ''hybrid system'' that is capable of providing the right type of energy, at the right time, in the right place. At the direction of DOE-NE and DOE-EERE leadership, project leads at Idaho National Laboratory (INL), National Renewable Energy Laboratory (NREL) and Massachusetts Institute of Technology (MIT) have identified and engaged stakeholders in discussing integrated energy systems that would optimize renewable and nuclear energy integration on a region-by-region basis. Subsequent work will entail conduct of technical, economic, environmental and socio-political evaluations of the leading integrated system options based on a set of criteria established with stakeholder input. The Foundational Workshop for Integrated Nuclear - Renewable Energy Systems was organized around the following objectives: 1. Identify and refine priority region-specific opportunities for integrated nuclear-renewable energy systems in the U.S.; 2. Select Figures of Merit (FOM) to rank and prioritize candidate systems; 3. Discuss enabling technology development needs; 4. Identify analysis requirements, capabilities and gaps to

The Nuclear Criticality Information System: An update

International Nuclear Information System (INIS)

Koponen, B.L.

1991-07-01

The US Department of Energy's Nuclear Criticality Information System (NCIS) has served the criticality community for the past ten years with publications and with an online information system. NCIS provides a mean for widely distributed nuclear criticality specialists to communicate and work together instantly. Users of the system may receive assistance from all members of the NCIS community, which provides a much broader base of support than is available at any single site. When unified by NCIS, these diverse specialists provide a resource that has proven to be very useful in the safe handling of fissile material. NCIS also is a source of current nuclear criticality safety information; the rapid access of such up-to-date information on the handling of fissile materials outside of nuclear reactors is international in scope, extending beyond political and geographical boundaries

Nuclear plants gain integrated information systems

International Nuclear Information System (INIS)

Villavicencio-Ramirez, A.; Rodriquez-Alvarez, J.M.

1994-01-01

With the objective of simplifying the complex mesh of computing devices employed within nuclear power plants, modern technology and integration techniques are being used to form centralized (but backed up) databases and distributed processing and display networks. Benefits are immediate as a result of the integration and the use of standards. The use of a unique data acquisition and database subsystem optimizes the high costs of engineering, as this task is done only once for the life span of the system. This also contributes towards a uniform user interface and allows for graceful expansion and maintenance. This article features an integrated information system, Sistema Integral de Informacion de Proceso (SIIP). The development of this system enabled the Laguna Verde Nuclear Power plant to fully use the already existing universe of signals and its related engineering during all plant conditions, namely, start up, normal operation, transient analysis, and emergency operation. Integrated systems offer many advantages over segregated systems, and this experience should benefit similar development efforts in other electric power utilities, not only for nuclear but also for other types of generating plants

The group-theoretical approach to the description of nuclear states

International Nuclear Information System (INIS)

Baktybaev, K.

2001-01-01

Study of symmetrical environmental properties, including nuclei, nuclear particles, atoms and molecules has very important, and sometimes determinative meaning. The role of visible symmetry, in other words of the world beauty is generally known, and studied for a long time. The internal symmetry of material world (isotopic, angular, gauge, dynamic etc.), playing vitally important significance for its structure, creation and development has been widely studied for last years. The development of conception of dynamic symmetry and supersymmetry in the structure of nuclear system condition and their supplement under studies of specific nuclei properties is considered in the present article. The next section includes the summary of the main point of dynamic symmetry and its connection to corresponding Lie algebra and techniques of physical operators construction through generators of chosen algebra and its subalgebra. Section 3 states the dynamic-symmetric properties of atomic nuclei collective states, which are described by the model of interactive bosons. Section 4 is dedicated to conception of dynamic supersymmetry, its supplement under structure study of quasi-particle and collective states of nuclei and all interactions. In particular, the theory is applied for study of fermion and boson states in the even isotopes Pd, Dy and Er

11-th International conference Nuclear power safety and nuclear education - 2009. Abstracts. Part 1. Session: Safety of nuclear technology; Innovative nuclear systems and fuel cycle; Nuclear knowledge management

International Nuclear Information System (INIS)

2009-01-01

The book includes abstracts of the 11-th International conference Nuclear power safety and nuclear education - 2009 (29 Sep - 2 Oct, 2009, Obninsk). Problems of safety of nuclear technology are discussed, innovative nuclear systems and fuel cycles are treated. Abstracts on professional education for nuclear power and industry are presented. Nuclear knowledge management are discussed

Croatian National System of Nuclear Materials Control

International Nuclear Information System (INIS)

Biscan, R.

1998-01-01

In the process of economic and technological development of Croatia by using or introducing nuclear power or in the case of international co-operation in the field of peaceful nuclear activities, including international exchange of nuclear material, Croatia should establish and implement National System of Nuclear Materials Control. Croatian National System of accounting for and control of all nuclear material will be subjected to safeguards under requirements of Agreement and Additional Protocol between the Republic of Croatia and the International Atomic Energy Agency (IAEA) for the Application of Safeguards in Connection with the Treaty on the Non-Proliferation of Nuclear Weapons (NPT). The decision by NPT parties at the 1995 NPT Review and Extension Conference to endorse the Fullscope IAEA Safeguards Standard (FSS) as a necessary precondition of nuclear supply means that states are obliged to ensure that the recipient country has a FSS agreement in place before any nuclear transfer can take place (Ref. 1). The FSS standard of nuclear supply is a central element of the Nuclear Suppliers Group (NSG) Guidelines which the NSG adopted in 1992 and should be applied to members and non-members of the NSG. The FSS standard of nuclear supply in general allows for NPT parties or countries which have undertaken the same obligations through other treaty arrangements, to receive favourable treatment in nuclear supply arrangements. However, the Iraqi experience demonstrate that trade in nuclear and dual-use items, if not properly monitored, can contribute to a nuclear weapons program in countries acting contrary to their non-proliferation obligation. Multilateral nuclear export control mechanisms, including the FSS supply standard, provide the basis for co-ordination and standardisation of export control measures. (author)

Ventilation systems and components of nuclear power plants

International Nuclear Information System (INIS)

1997-01-01

The most important radiation and nuclear safety requirements for the design and manufacture of nuclear power plant ventilation systems and components are presented in the guide. Also the regulatory activities of the Finnish Centre for Radiation and Nuclear Safety (STUK) as regards the ventilation systems and components are explained. Documents and data which shall be submitted to STUK during the various phases of the regulatory procedure relating to the design, construction, commissioning and operation of the nuclear power plants are presented. (13 refs.)

Building a medical system for nuclear facilities

International Nuclear Information System (INIS)

Maeda, Mitsuya

2016-01-01

To build a medical system for nuclear facilities, I explained what kinds of actions were performed with the TEPCO Fukushima Daiichi Nuclear Power Plant Accident and what kinds of actions are going to be performed in the future. We examined the health and medical care of the emergency workers in nuclear facilities including TEPCO Fukushima Daiichi Nuclear Power Plant from 2014 to 2015 in the Ministry of Health, Labour and Welfare (MHLW). We carried out a detailed hearing from stakeholders of electric companies and medical institutions about the medical system in nuclear facilities carrying out urgent activities. It has been said that the electric company is responsible to maintain the medical system for affected workers in nuclear facilities. However, TEPCO could not find the medical staff, such as doctors, by their own effort at the TEPCO Fukushima Daiichi Nuclear Power Plant Accident. The network of doctors familiar with emergency medical care support dispatched the medical staff after July of 2011. The stakeholders indicated that the following six tasks must be resolved: (1) the fact that no electric company performs the action of bringing up medical staff who can be dispatched into nuclear facilities in emergencies in 2015; (2) bringing up personnel in charge of radiation management and logistics other than the medical staff, such as doctors; (3) cooperation with the community medicine system given the light and shade by nuclear facilities; (4) performing training for the many concurrent wounded based on the scenario of a severe accident; (5) indicating both the condition of the contract and the guarantee of status that is appropriate for dispatched medical staffs; and (6) clarifying the organization of the network of stakeholders. The stakeholders showed the future directionality as follows: (1) To recruit the medical staff expected to be dispatched into nuclear facilities, (2) to carry out the discussion and conveyance training to strengthen cooperation with

Proliferation resistance assessment of nuclear systems

International Nuclear Information System (INIS)

1978-09-01

The paper focuses on examining the degree to which nuclear systems could be used to acquire nuclear weapons material. It establishes a framework for proliferation resistance assessment and illustrates its applicability through an analysis of reference systems for once-through cycles, breeder cycles and thermal recycle. On a more tentative basis, the approach is applied to various alternative technical and institutional measures. This paper was also submitted to Working Groups 5 and 8

SNAP: a tool for nuclear physical protection system modeling

International Nuclear Information System (INIS)

Engi, D.; Grant, F.H. III.

1979-10-01

Nuclear safeguards systems are concerned, in part, with the physical protection of nuclear materials. The function of a physical protection system is to define the facility against adversary activities which could lead to theft of nuclear material or sabotage resulting in a radiological release. The Safeguards Network Analysis Procedure (SNAP) provides a convenient and standard analysis methodology for the evaluation of physical protection system analysis. This paper describes a detailed application of SNAP to a hypothetical nuclear facility

Operator support system for nuclear power plants

International Nuclear Information System (INIS)

Mori, Nobuyuki; Tai, Ichiro; Sudo, Osamu; Naito, Norio.

1987-01-01

The nuclear power generation in Japan maintains the high capacity factor, and its proportion taken in the total generated electric power exceeded 1/4, thus it has become the indispensable energy source. Recently moreover, the nuclear power plants which are harmonious with operators and easy to operate are demanded. For realizing this, the technical development such as the heightening of operation watching performance, the adoption of automation, and the improvement of various man-machine systems for reducing the burden of operators has been advanced by utilizing electronic techniques. In this paper, the trend of the man-machine systems in nuclear power plants, the positioning of operation support system, the support in the aspects of information, action and knowledge, the example of a new central control board, the operation support system using a computer, an operation support expert system and the problems hereafter are described. As the development of the man-machine system in nuclear power plants, the upgrading from a present new central control board system PODIA through A-PODIA, in which the operational function to deal with various phenomena arising in plants and safety control function are added, to 1-PODIA, in which knowledge engineering technology is adopted, is expected. (Kako, I.)

Solitons in PT-symmetric potential with competing nonlinearity

International Nuclear Information System (INIS)

Khare, Avinash; Al-Marzoug, S.M.; Bahlouli, Hocine

2012-01-01

We investigate the effect of competing nonlinearities on beam dynamics in PT-symmetric potentials. In particular, we consider the stationary nonlinear Schrödinger equation (NLSE) in one dimension with competing cubic and generalized nonlinearity in the presence of a PT-symmetric potential. Closed form solutions for localized states are obtained. These solitons are shown to be stable over a wide range of potential parameters. The transverse power flow associated with these complex solitons is also examined. -- Highlights: ► Effect of competing nonlinearities on beam dynamics in PT-symmetric potentials. ► Closed form solutions for localized states are. ► The transverse power flow associated with these complex solitons is also examined.

Nuclear deterrence: Inherent escalation?

International Nuclear Information System (INIS)

Bergbauer, J.R. Jr.

1993-01-01

Despite 40 years of peace between the super powers, there is increasing clamor to the effect that nuclear war between the super powers is imminent; or could occur through escalation from a minor conflict; or could result from harsh rhetoric (but only on the part of the U.S.) in the super power dialogue. The factor that is ignored is that a massive nuclear attack would be rational ONLY if that attack could inflict such damage that the other super power could not launch a significant retaliatory nuclear attack. ONLY in this circumstance would there be any profit in launching an initial Strategic Nuclear Attack. This First Strike capability is not now possessed nor projected to be developed by either super power. As long as ANY possible Strategic Nuclear Attack against the national territory of one super power would be insufficient to prevent an equally destructive retaliatory attack, then a Strategic Nuclear Attack would inevitably result in the destruction of both and would be profitless, hence, pointless. This situation describes Mutually Assured Destruction (MAD), the governing conflict paradigm applicable to both super powers. The only convential attack that would even remotely rival the national-destruction potential of a Strategic Nuclear Attack and could cause the attacked power to consider launching a retaliatory Strategic Nuclear Attack would be a massive land-air invasion/occupation of one super power by the other. Since neither super power can successfully execute such a conventional invasion/occupation, this situation is moot. The geo-political environments of the two super powers are so asymmetrical and their military positions so symmetrical that the probability of ANY forseeable situation resulting in their resorting to a Strategic Nuclear Exchange is vanishingly small. It is possible escape the Chicken-Little syndrome and, instead, devote energy to ensuring the maintenance of this favorable, but fragile, world system

Transactions of the fifth symposium on space nuclear power systems

Energy Technology Data Exchange (ETDEWEB)

El-Genk, M.S.; Hoover, M.D. (eds.)

1988-01-01

This paper contains the presented papers at the fourth symposium on space nuclear power systems. Topics of these paper include: space nuclear missions and applications, reactors and shielding, nuclear electric and nuclear propulsion, high-temperature materials, instrumentation and control, energy conversion and storage, space nuclear fuels, thermal management, nuclear safety, simulation and modeling, and multimegawatt system concepts. (LSP)

Establishment of nuclear knowledge and information infrastructure; establishment of web-based database system for nuclear events

Energy Technology Data Exchange (ETDEWEB)

Park, W. J.; Kim, K. J. [Korea Atomic Energy Research Institute , Taejeon (Korea); Lee, S. H. [Korea Institute of Nuclear Safety, Taejeon (Korea)

2001-05-01

Nuclear events data reported by nuclear power plants are useful to prevent nuclear accidents at the power plant by examine the cause of initiating events and removal of weak points in the aspects of operational safety, and to improve nuclear safety in design and operation stages by backfitting operational experiences and practices 'Nuclear Event Evaluation Database : NEED' system distributed by CD-ROM media are upgraded to the NEED-Web (Web-based Nuclear Event Evaluation Database) version to manage event data using database system on network basis and the event data and the statistics are provided to the authorized users in the Nuclear Portal Site and publics through Internet Web services. The efforts to establish the NEED-Web system will improve the integrity of events data occurred in Korean nuclear power plant and the usability of data services, and enhance the confidence building and the transparency to the public in nuclear safety. 11 refs., 27 figs. (Author)

Nuclear legislation system and nuclear program outlook in Thailand

International Nuclear Information System (INIS)

Charoensri, Apisara; Morev, Mikhail N.; Imazu, Hidenori; Kosako, Toshiso; Iimoto, Takeshi

2009-01-01

In Thailand, radioactive materials are widely used for the industry, medicine, research and development fields. Reported here are background and recent developments in the national nuclear legislation system, including regulation of radiation safety and current status of nuclear program in Thailand. Under the Atomic Energy for Peace Act, the Thai Atomic Energy Commission (Thai AEC) is authorized to approve regulations respecting, the conversion, enrichment, processing, reprocessing, possession, import, export, use, packaging, transport, management and storage of nuclear materials. The most recent developments are related to the New Ministerial Regulation on Licensing Requirements Procedures and Nuclear Material, By-Product or Atomic Energy Processing B. E 2550 (A. D. 2007) issued under the Atomic Energy for Peace Act, B. E. 2504 (A. D. 1961). Currently, the Thai Cabinet is discussing the draft new Atomic Energy for Peace Act which is to revise the Act. The draft Act is to sets forth criteria for protecting individuals, society and the environment from radiation hazards with the perspective for anticipated nuclear power sector development in Thailand. (author)

Cycle Trades for Nuclear Thermal Rocket Propulsion Systems

Science.gov (United States)

White, C.; Guidos, M.; Greene, W.

2003-01-01

Nuclear fission has been used as a reliable source for utility power in the United States for decades. Even in the 1940's, long before the United States had a viable space program, the theoretical benefits of nuclear power as applied to space travel were being explored. These benefits include long-life operation and high performance, particularly in the form of vehicle power density, enabling longer-lasting space missions. The configurations for nuclear rocket systems and chemical rocket systems are similar except that a nuclear rocket utilizes a fission reactor as its heat source. This thermal energy can be utilized directly to heat propellants that are then accelerated through a nozzle to generate thrust or it can be used as part of an electricity generation system. The former approach is Nuclear Thermal Propulsion (NTP) and the latter is Nuclear Electric Propulsion (NEP), which is then used to power thruster technologies such as ion thrusters. This paper will explore a number of indirect-NTP engine cycle configurations using assumed performance constraints and requirements, discuss the advantages and disadvantages of each cycle configuration, and present preliminary performance and size results. This paper is intended to lay the groundwork for future efforts in the development of a practical NTP system or a combined NTP/NEP hybrid system.

Asymmetric nuclear matter in a modified quark meson coupling model

International Nuclear Information System (INIS)

Mishra, R.N.; Sahoo, H.S.; Panda, P.K.; Barik, N.

2014-01-01

In an earlier attempt we have successfully used this model in developing the nuclear equation of state and analysed various other bulk properties of symmetric nuclear matter with the dependence of quark masses. In the present work we want to apply the model to analyze asymmetric nuclear matter with the variation of the asymmetry parameter y p as well as analyze the effects of symmetry energy and the slope of the symmetry energy L

Computer System Analysis for Decommissioning Management of Nuclear Reactor

International Nuclear Information System (INIS)

Nurokhim; Sumarbagiono

2008-01-01

Nuclear reactor decommissioning is a complex activity that should be planed and implemented carefully. A system based on computer need to be developed to support nuclear reactor decommissioning. Some computer systems have been studied for management of nuclear power reactor. Software system COSMARD and DEXUS that have been developed in Japan and IDMT in Italy used as models for analysis and discussion. Its can be concluded that a computer system for nuclear reactor decommissioning management is quite complex that involved some computer code for radioactive inventory database calculation, calculation module on the stages of decommissioning phase, and spatial data system development for virtual reality. (author)

Nuclear Power Safety Reporting System. Final evaluation results

International Nuclear Information System (INIS)

Finlayson, F.C.; Newton, R.D.

1986-02-01

This document presents the results of a study conducted by the US Nuclear Regulatory Commission of an unobtrusive, voluntary, anonymous third-party managed, nonpunitive human factors data gathering system (the Nuclear power Safety Reporting System - NPSRS) for the nuclear electric power production industry. The data to be gathered by the NPSRS are intended for use in identifying and quantifying the factors that contribute to the occurrence of significant safety incidents involving humans in nuclear power plants. The NPSRS has been designed to encourage participation in the System through guarantees of reporter anonymity provided by a third-party organization that would be responsible for NPSRS management. As additional motivation to reporters for contributing data to the NPSRS, conditional waivers of NRC disciplinary action would be provided to individuals. These conditional waivers of immunity would apply to potential violations of NRC regulations that might be disclosed through reports submitted to the System about inadvertent, noncriminal incidents in nuclear plants. This document summarizes the overall results of the study of the NPSRS concept. In it, a functional description of the NPSRS is presented together with a review and assessment of potential problem areas that might be met if the System were implemented. Conclusions and recommendations resulting from the study are also presented. A companion volume (NUREG/CR-4133, Nuclear Power Safety Reporting System: Implementation and Operational Specifications'') presented in detail the elements, requirements, forms, and procedures for implementing and operating the System. 13 refs

Research on export system of marine nuclear power device

International Nuclear Information System (INIS)

Fu Mingyu; Bian Xinqian; Shi Ji; Xin Chengdong; Wei Dong

2002-01-01

A marine nuclear power plant simulation system is founded, and a management expert system, which can administer and diagnose the typical faults, is constituted by the intelligent expert theory. This real-time expert system can analyze the reason of the typical fault caused by the nuclear power plant practically running and give the best solvent by the expert knowledge reasoning in the repository; a neural network fault inspection and diagnosis expert system which can inspect every equipment continually and give the faults diagnosis result based on the inspective dates is established. Based on the three hierarchical architecture, the operation performance is improved very much by using of the neural network fault inspection and diagnosis expert system to inspect and diagnose the nuclear power plant faults and the management expert system to supervise the nuclear power plant running. The expert system research can give guidance for the marine nuclear power plant safety operation

Chemistry management system for nuclear power plants

International Nuclear Information System (INIS)

Nagasawa, Katsumi; Maeda, Katsuji

1998-01-01

Recently, the chemistry management in the nuclear power plants has been changing from the problem solution to the predictive diagnosis and maintenance. It is important to maintain the integrity of plant operation by an adequate chemistry control. For these reasons, many plant operation data and chemistry analysis data should be collected and treated effectively to evaluate chemistry condition of the nuclear power plants. When some indications of chemistry anomalies occur, quick and effective root cause evaluation and countermeasures should be required. The chemistry management system has been developed as to provide sophisticate chemistry management in the nuclear power plants. This paper introduces the concept and functions of the chemistry management system for the nuclear power plants. (author)

Meson theory and nuclear matter

International Nuclear Information System (INIS)

Skyrme, T.H.R.

1994-01-01

An attempt is made to justify the use of the concept of a 'mesic fluid' in connection with the structure of nuclear matter. A transformation is made of the usual symmetric pseudo-scalar meson theory to bring into evidence certain saturation properties, which provide a natural basis for the use of a 'self-consistent' field in the discussion of nuclear structure. Fluctuations about this semi-classical saturated state will give rise to residual interparticle forces within the nucleus, and are also briefly considered in relation to electromagnetic interactions. (author). 5 refs

Symmetric Double Quantum Dot Energy States in a High Magnetic Field

International Nuclear Information System (INIS)

Morgenstern Horing, Norman J; Sawamura, Makoto

2011-01-01

The dynamical Green's function and energy spectrum of a 2D symmetric quantum double-dot system on a planar host in a normal magnetic field are analyzed here, representing the two dots by Dirac delta function potentials. The proliferation of energy levels due to Landau quantization is examined in detail.

Integrated Nuclear-Renewable Energy Systems: Foundational Workshop Report

Energy Technology Data Exchange (ETDEWEB)

Bragg-Sitton, Shannon [Idaho National Lab. (INL), Idaho Falls, ID (United States); Boardman, Richard [Idaho National Lab. (INL), Idaho Falls, ID (United States); Ruth, Mark [National Renewable Energy Lab. (NREL), Golden, CO (United States); Zinaman, Owen [National Renewable Energy Lab. (NREL), Golden, CO (United States); Forsberg, Charles [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Collins, John [Idaho National Lab. (INL), Idaho Falls, ID (United States)

2014-08-01

The U.S. Department of Energy (DOE) recognizes the need to transform the energy infrastructure of the U.S. and elsewhere to systems that can drastically reduce environmental impacts in an efficient and economically viable manner while utilizing both hydrocarbon resources and clean energy generation sources. Thus, DOE is supporting research and development that could lead to more efficient utilization of clean energy generation sources, including renewable and nuclear options. A concept being advanced by the DOE Offices of Nuclear Energy (NE) and Energy Efficiency and Renewable Energy (EERE) is tighter coupling of nuclear and renewable energy sources in a manner that produces new energy currency for the combined electricity grid, industrial manufacturing, and the transportation energy sectors. This integration concept has been referred to as a “hybrid system” that is capable of providing the right type of energy, at the right time, in the right place. At the direction of DOE-NE and DOE-EERE leadership, project leads at Idaho National Laboratory (INL), National Renewable Energy Laboratory (NREL) and Massachusetts Institute of Technology (MIT) have identified and engaged stakeholders in discussing integrated energy systems that would optimize renewable and nuclear energy integration on a region-by-region basis. Subsequent work will entail conduct of technical, economic, environmental and socio-political evaluations of the leading integrated system options based on a set of criteria established with stakeholder input. The Foundational Workshop for Integrated Nuclear – Renewable Energy Systems was organized around the following objectives: 1. Identify and refine priority region-specific opportunities for integrated nuclear-renewable energy systems in the U.S.; 2. Select Figures of Merit (FOM) to rank and prioritize candidate systems; 3. Discuss enabling technology development needs; 4. Identify analysis requirements, capabilities and gaps to estimate FOM for

Development of integrated nuclear data utilization system for innovative reactors

International Nuclear Information System (INIS)

Naoki, Yamano; Masayuki, Igashira; Akira, Hasegawa; Kiyoshi, Kato

2005-01-01

An integrated nuclear data utilization system has been developing for innovative nuclear energy systems such as innovative reactors and accelerator-driven systems. The system has been constructed as a modular code system, which consists of a managing system and two subsystems. The management system named CONDUCT controls system resource management of the PC Linux server and the user authentication through Internet access. A subsystem is the nuclear data search and plotting subsystem based on a SPES engine developed by Hokkaido University. Nuclear data such as EXFOR, JENDL-3.3, ENDF/B-VI and JEFF-3.1 can be searched and plotted in the subsystem. The other is the nuclear data processing and utilization subsystem, which is able to handle JENDL-3.3, ENDF/B-VI and JEFF-3.1 to generate point-wise and group cross sections in several formats, and perform various criticality and shielding benchmarks for verification of nuclear data and validation of design methods for innovative reactors. This paper presents an overview of the integrated nuclear data utilization system, describes the progress of the system development to examine the operability of the user interface and discuss specifications of the two subsystems. (authors)

Nonlinear PT-symmetric plaquettes

International Nuclear Information System (INIS)

Li Kai; Kevrekidis, P G; Malomed, Boris A; Günther, Uwe

2012-01-01

We introduce four basic two-dimensional (2D) plaquette configurations with onsite cubic nonlinearities, which may be used as building blocks for 2D PT-symmetric lattices. For each configuration, we develop a dynamical model and examine its PTsymmetry. The corresponding nonlinear modes are analyzed starting from the Hamiltonian limit, with zero value of the gain–loss coefficient, γ. Once the relevant waveforms have been identified (chiefly, in an analytical form), their stability is examined by means of linearization in the vicinity of stationary points. This reveals diverse and, occasionally, fairly complex bifurcations. The evolution of unstable modes is explored by means of direct simulations. In particular, stable localized modes are found in these systems, although the majority of identified solutions are unstable. This article is part of a special issue of Journal of Physics A: Mathematical and Theoretical devoted to ‘Quantum physics with non-Hermitian operators’. (paper)

Knowledge Based Help desk System in Nuclear Malaysia

International Nuclear Information System (INIS)

Mohamad Safuan Sulaiman; Abdul Muin Abdul Rahman; Norzalina Nasirudin; Khairiel Adyani Abdul Ghani; Abdul Aziz Mhd Ramli; Mohd Ashhar Khalid

2012-01-01

Knowledge based (K-based) Help desk system is a knowledge oriented web based system that provides support to business process of the technical service providers. It is a multi-centric system which focuses on end-users, technical workers and higher level management through utilization of knowledge which resides and grows within the system. The objectives of the system are to be a user-friendly, capture technical knowledge for efficient performance and educating users for self reliance. These were achieved through the improvement of the help desk business process and better management of technical knowledge. This system has been tested and implemented in Information Technology Center (IT), Engineering Division (BKJ) and Instrumentation and Automation Center (IAC) at the Malaysian Nuclear Agency (Nuclear Malaysia). Higher levels of user satisfaction and faster growth in technical knowledge repository have been recorded in the system. This paper describes the help desk system in the perspective of management of its technical knowledge contributing to strengthening organizational knowledge asset of Nuclear Malaysia as national nuclear research institution. (Author)

Selection of nuclear power information database management system

International Nuclear Information System (INIS)

Zhang Shuxin; Wu Jianlei

1996-01-01

In the condition of the present database technology, in order to build the Chinese nuclear power information database (NPIDB) in the nuclear industry system efficiently at a high starting point, an important task is to select a proper database management system (DBMS), which is the hinge of the matter to build the database successfully. Therefore, this article explains how to build a practical information database about nuclear power, the functions of different database management systems, the reason of selecting relation database management system (RDBMS), the principles of selecting RDBMS, the recommendation of ORACLE management system as the software to build database and so on

Space nuclear power systems, Part 2

International Nuclear Information System (INIS)

El-Genk, M.S.; Hoover, M.D.

1992-01-01

This volume, number two of three, contains the reviewed and edited papers were being presented at the Ninth Symposium in Albuquerque, New Mexico, 12--16 January 1992. The objective of the symposium, and hence these volumes, is to summarize the state of knowledge in the area of space nuclear power and propulsion and to provide a forum at which the most recent findings and important new developments can be presented and discussed. Topics included is this volume are: reactor and power systems control; thermionic energy conversion; space missions and power needs; key issues in nuclear and propulsion; nuclear thermal propulsion; manufacturing and processing; thermal management; space nuclear safety; and nuclear testing and production facilities

The Management System for Nuclear Installations (Russian Edition)

International Nuclear Information System (INIS)

2014-01-01

This Safety Guide is applicable throughout the lifetime of a nuclear installation, including any subsequent period of institutional control, until there is no significant residual radiation hazard. For a nuclear installation, the lifetime includes site evaluation, design, construction, commissioning, operation and decommissioning. These stages in the lifetime of a nuclear installation may overlap. This Safety Guide may be applied to nuclear installations in the following ways: (a)To support the development, implementation, assessment and improvement of the management system of those organizations responsible for research, site evaluation, design, construction, commissioning, operation and decommissioning of a nuclear installation; (b)As an aid in the assessment by the regulatory body of the adequacy of the management system of a nuclear installation; (c)To assist an organization in specifying to a supplier, via contractual documentation, any specific element that should be included within the supplier's management system for the supply of products. This Safety Guide follows the structure of the Safety Requirements publication on The Management System for Facilities and Activities, whereby: (a)Section 2 provides recommendations on implementing the management system, including recommendations relating to safety culture, grading and documentation. (b)Section 3 provides recommendations on the responsibilities of senior management for the development and implementation of an effective management system. (c)Section 4 provides recommendations on resource management, including guidance on human resources, infrastructure and the working environment. (d)Section 5 provides recommendations on how the processes of the installation can be specified and developed, including recommendations on some generic processes of the management system. (e)Section 6 provides recommendations on the measurement, assessment and improvement of the management system of a nuclear installation. (f

The Management System for Nuclear Installations Safety Guide

International Nuclear Information System (INIS)

2009-01-01

This Safety Guide is applicable throughout the lifetime of a nuclear installation, including any subsequent period of institutional control, until there is no significant residual radiation hazard. For a nuclear installation, the lifetime includes site evaluation, design, construction, commissioning, operation and decommissioning. These stages in the lifetime of a nuclear installation may overlap. This Safety Guide may be applied to nuclear installations in the following ways: (a)To support the development, implementation, assessment and improvement of the management system of those organizations responsible for research, site evaluation, design, construction, commissioning, operation and decommissioning of a nuclear installation; (b)As an aid in the assessment by the regulatory body of the adequacy of the management system of a nuclear installation; (c)To assist an organization in specifying to a supplier, via contractual documentation, any specific element that should be included within the supplier's management system for the supply of products. This Safety Guide follows the structure of the Safety Requirements publication on The Management System for Facilities and Activities, whereby: (a)Section 2 provides recommendations on implementing the management system, including recommendations relating to safety culture, grading and documentation. (b)Section 3 provides recommendations on the responsibilities of senior management for the development and implementation of an effective management system. (c)Section 4 provides recommendations on resource management, including guidance on human resources, infrastructure and the working environment. (d)Section 5 provides recommendations on how the processes of the installation can be specified and developed, including recommendations on some generic processes of the management system. (e)Section 6 provides recommendations on the measurement, assessment and improvement of the management system of a nuclear installation. (f

Seminar in Critical Inquiry Twenty-first Century Nuclear Systems

Energy Technology Data Exchange (ETDEWEB)

LeMone, D. V.

2002-02-25

Critical Inquiry, has not only been successful in increasing university student retention rate but also in improving student academic performance beyond the initial year of transition into the University. The seminar course herein reviewed is a balanced combination of student personal and academic skill development combined with a solid background in modern nuclear systems. It is a valid premise to assume that entering students as well as stakeholders of the general public demonstrate equal levels of capability. Nuclear systems is designed to give a broad and basic knowledge of nuclear power, medical, industrial, research, and military systems (nuclear systems) in 20-25 hours.

Seminar in Critical Inquiry Twenty-first Century Nuclear Systems

International Nuclear Information System (INIS)

LeMone, D. V.

2002-01-01

Critical Inquiry, has not only been successful in increasing university student retention rate but also in improving student academic performance beyond the initial year of transition into the University. The seminar course herein reviewed is a balanced combination of student personal and academic skill development combined with a solid background in modern nuclear systems. It is a valid premise to assume that entering students as well as stakeholders of the general public demonstrate equal levels of capability. Nuclear systems is designed to give a broad and basic knowledge of nuclear power, medical, industrial, research, and military systems (nuclear systems) in 20-25 hours

Transactions of the fourth symposium on space nuclear power systems

Energy Technology Data Exchange (ETDEWEB)

El-Genk, M.S.; Hoover, M.D. (eds.)

1987-01-01

This paper contains the presented papers at the fourth symposium on space nuclear power systems. Topics of these papers include: space nuclear missions and applications, reactors and shielding, nuclear electric and nuclear propulsion, refractory alloys and high-temperature materials, instrumentation and control, energy conversion and storage, space nuclear fuels, thermal management, nuclear safety, simulation and modeling, and multimegawatt system concepts. (LSP)

Database retrieval systems for nuclear and astronomical data

International Nuclear Information System (INIS)

Suda, Takuma; Korennov, Sergei; Otuka, Naohiko; Yamada, Shimako; Katsuta, Yutaka; Ohnishi, Akira; Kato, Kiyoshi; Fujimoto, Masayuki Y.

2006-01-01

Data retrieval and plot systems of nuclear and astronomical data are constructed on a common platform. Web-based systems will soon be opened to the users of both fields of nuclear physics and astronomy. (author)

Emittance growth in non-symmetric beam configurations

International Nuclear Information System (INIS)

Anderson, O.A.

1996-06-01

Emittance growth in intense beams due to nonuniformity, mismatch, and misalignment has been analyzed by Reiser for the special case of axisymmetry. A more complex problem occurs in cases where a number of discrete beamlets are to be merged into a single focusing channel, for example, in designs for Heavy Ion Fusion drivers or Magnetic Fusion negative-ion systems. Celata, assuming the system to be perfectly matched and aligned, analyzed the case of four round beamlets arranged in a square array. We generalize these previous studies and analyze emittance growth in systems that are less symmetric. We include beam systems that are not necessarily matched and where the x and y moments may be unequal. We also include the possibility of initial convergence velocities that may differ in the two planes and allow for misalignment of the beam center-of-mass position and direction

Nuclear space power systems for orbit raising and maneuvering

International Nuclear Information System (INIS)

Buden, D.; Sullivan, J.A.

1984-01-01

Reference is made to recent studies which have shown that direct thrust nuclear rockets for routine orbit raising and near-earth space tug missions are probably not cost-effective. The need for additional trade-off studies and comparisons of direct-thrust nuclear systems with chemical systems to clarify the role of nuclear rockets in missions requiring rapid orbit maneuvering is stressed. Attention is confined here to nuclear electric propulsion considerations. Low-mass nuclear power plants are constructed to optimize nuclear electric propulsion systems. Electric power levels from 100 kilowatts to as much as several megawatts are desirable. The goals for the power plant specific mass are 20-30 kg/kW at the lower powers to 2-4 kg/kW at the higher powers

Innovation in the Safety of nuclear systems: fundamental aspects

International Nuclear Information System (INIS)

Herranz, L. E.

2009-01-01

Safety commercial nuclear reactors has been an indispensable condition for future enlargement of power generation based on nuclear technology. Its fundamental principle, defence in depth, far from being outdated, is still adopted as a key foundation in the advanced nuclear system (generations III and IV). Nevertheless, the cumulative experience gained in the operation and maintenance of nuclear reactors, the development of methodologies like the probabilistic safety analysis, the use of passive safety systems and, even, the inherent characteristics of some new design (which exclude accident scenarios), allow estimating safety figures of merit even more outstanding that those achieved in the second generation of nuclear reactors. This safety innovation of upcoming nuclear reactors has entailed a huge investigation program (generation III) that will be focused on optimizing and demonstrating the postulated safety of future nuclear systems (Generation IV). (Author)

Investigation of human system interface design in nuclear power plant

International Nuclear Information System (INIS)

Feng Yan; Zhang Yunbo; Wang Zhongqiu

2012-01-01

The paper introduces the importance of HFE in designing nuclear power plant, and introduces briefly the content and scope of HFE, discusses human system interface design of new built nuclear power plants. This paper also describes human system interface design of foreign nuclear power plant, and describes in detail human system interface design of domestic nuclear power plant. (authors)

Energy accounting in nuclear power systems

International Nuclear Information System (INIS)

Symonds, J.L.; Essam, P.; Stocks, K.

1976-01-01

Energy analysis is a systematic way of tracing and accounting for the flows of energy through an industrial system and apportioning a quantity of the primary energy input to each of the goods and services sent out. The application of energy accounting to nuclear power stations and their growth in generating systems is discussed. Misunderstandings arising from discrepancies and weaknesses in some published simple analyses of hypothetical growth situations are outlined. Results of a more complex energy flow analysis are used to demonstrate that current nuclear energy programs are running at an energy profit. Large fossil fuel savings will occur in a real electrical grid system under anticipated nuclear power growth rates. These savings will give a new dimension in planning the use of fossil energy resources which will still be needed for transport and industrial processes, such as steelmaking, for some time to come. (author)

Energy accounting in nuclear power systems

International Nuclear Information System (INIS)

Symonds, J.L.; Essam, P.; Stocks, K.

1975-10-01

Energy analysis is a systematic way of tracing and accounting for the flows of energy through an industrial system and apportioning a quantity of the primary energy input of the goods and services sent out. The application of energy accounting to nuclear power stations and their growth in generating systems is discussed. Misunderstandings arising from discrepancies and weaknesses in some published simple analyses of hypothetical growth situations are outlined. Results of a more complex energy flow analysis are used to demonstrate that current nuclear energy programs are running at an energy profit. Large fossil fuel savings will occur in a real electrical grid system under anticipated nuclear power growth rates. These savings will give a new dimension in planning the use of fossil energy resources which will still be needed for transport and industrial processes, such as steel-making, for some time to come. (author)

Fuzzy systems and soft computing in nuclear engineering

International Nuclear Information System (INIS)

Ruan, D.

2000-01-01

This book is an organized edited collection of twenty-one contributed chapters covering nuclear engineering applications of fuzzy systems, neural networks, genetic algorithms and other soft computing techniques. All chapters are either updated review or original contributions by leading researchers written exclusively for this volume. The volume highlights the advantages of applying fuzzy systems and soft computing in nuclear engineering, which can be viewed as complementary to traditional methods. As a result, fuzzy sets and soft computing provide a powerful tool for solving intricate problems pertaining in nuclear engineering. Each chapter of the book is self-contained and also indicates the future research direction on this topic of applications of fuzzy systems and soft computing in nuclear engineering. (orig.)

Unidirectional Wave Vector Manipulation in Two-Dimensional Space with an All Passive Acoustic Parity-Time-Symmetric Metamaterials Crystal

Science.gov (United States)

Liu, Tuo; Zhu, Xuefeng; Chen, Fei; Liang, Shanjun; Zhu, Jie

2018-03-01

Exploring the concept of non-Hermitian Hamiltonians respecting parity-time symmetry with classical wave systems is of great interest as it enables the experimental investigation of parity-time-symmetric systems through the quantum-classical analogue. Here, we demonstrate unidirectional wave vector manipulation in two-dimensional space, with an all passive acoustic parity-time-symmetric metamaterials crystal. The metamaterials crystal is constructed through interleaving groove- and holey-structured acoustic metamaterials to provide an intrinsic parity-time-symmetric potential that is two-dimensionally extended and curved, which allows the flexible manipulation of unpaired wave vectors. At the transition point from the unbroken to broken parity-time symmetry phase, the unidirectional sound focusing effect (along with reflectionless acoustic transparency in the opposite direction) is experimentally realized over the spectrum. This demonstration confirms the capability of passive acoustic systems to carry the experimental studies on general parity-time symmetry physics and further reveals the unique functionalities enabled by the judiciously tailored unidirectional wave vectors in space.

EPRI expert system activities for nuclear utility industry application

International Nuclear Information System (INIS)

Naser, J.A.

1990-01-01

This paper reports on expert systems which have reached a level of maturity where they offer considerable benefits for the nuclear utility industry. The ability of expert systems to enhance expertise makes them an important tool for the nuclear utility industry in the areas of engineering, operations and maintenance. Benefits of expert system applications include comprehensive and consistent reasoning, reduction of time required for activities, retention of human expertise and ability to utilize multiple experts knowledge for an activity. The Electric Power Research Institute (EPRI) has been performing four basic activities to help the nuclear industry take advantage of this expert system technology. The first is the development of expert system building tools which are tailored to nuclear utility industry applications. The second is the development of expert system applications. The third is work in developing a methodology for verification and validation of expert systems. The last is technology transfer activities to help the nuclear utility industry benefit from expert systems. The purpose of this paper is to describe the EPRI activities

Review of Current Nuclear Vacuum System Technologies

International Nuclear Information System (INIS)

Carroll, M.; McCracken, J.; Shope, T.

2003-01-01

Nearly all industrial operations generate unwanted dust, particulate matter, and/or liquid wastes. Waste dust and particulates can be readily tracked to other work locations, and airborne particulates can be spread through ventilation systems to all locations within a building, and even vented outside the building - a serious concern for processes involving hazardous, radioactive, or nuclear materials. Several varieties of vacuum systems have been proposed and/or are commercially available for clean up of both solid and liquid hazardous and nuclear materials. A review of current technologies highlights both the advantages and disadvantages of the various systems, and demonstrates the need for a system designed to address issues specific to hazardous and nuclear material cleanup. A review of previous and current hazardous/nuclear material cleanup technologies is presented. From simple conventional vacuums modified for use in industrial operations, to systems specifically engineered for such purposes, the advantages and disadvantages are examined in light of the following criteria: minimal worker exposure; minimal secondary waste generation;reduced equipment maintenance and consumable parts; simplicity of design, yet fully compatible with all waste types; and ease of use. The work effort reviews past, existing and proposed technologies in light of such considerations. Accomplishments of selected systems are presented, including identified areas where technological improvements could be suggested

Tilting-connected symmetric algebras

OpenAIRE

Aihara, Takuma

2010-01-01

The notion of silting mutation was introduced by Iyama and the author. In this paper we mainly study silting mutation for self-injective algebras and prove that any representation-finite symmetric algebra is tilting-connected. Moreover we give some sufficient conditions for a Bongartz-type Lemma to hold for silting objects.

Distributed Searchable Symmetric Encryption

NARCIS (Netherlands)

Bösch, C.T.; Peter, Andreas; Leenders, Bram; Lim, Hoon Wei; Tang, Qiang; Wang, Huaxiong; Hartel, Pieter H.; Jonker, Willem

Searchable Symmetric Encryption (SSE) allows a client to store encrypted data on a storage provider in such a way, that the client is able to search and retrieve the data selectively without the storage provider learning the contents of the data or the words being searched for. Practical SSE schemes

Application of expert system to nuclear power plant operation and guidance system

International Nuclear Information System (INIS)

Goto, M.; Takada, Y.

1990-01-01

For a nuclear power plant, it is important that an expert system supplies useful information to the operator to meet the increasing demand for high-level plant operation. It is difficult to build a user-friendly expert system that supplies useful information in real time using existing general-purpose expert system shells. Therefore a domain-specific expert system shell with a useful knowledge representation for problem-solving in nuclear power plant operation was selected. The Plant Table (P/T) representation format was developed for description of a production system for nuclear power plant operation knowledge. The P/T consists of plant condition representation designed to process multiple inputs and single output. A large number of operation inputs for several plant conditions are divided into 'timing conditions', 'preconditions' and 'completion conditions' to facilitate knowledge-base build-up. An expert system for a Nuclear Power Plant Operation and Guidance System utilizing the P/T was developed to assist automatic plant operation and surveillance test operation. In these systems, automatic plant operation signals to the plant equipment and operation guidance messages to the operators are both output based on the processing and assessment of plant operation conditions by the P/T. A surveillance test procedure guide for major safety-related systems, such as those for emergency core cooling systems, is displayed on a CRT (Cathode Ray Tube) and test results are printed out. The expert system for a Nuclear Power Plant Operation and Guidance System has already been successfully applied to Japanese BWR plants

Nuclear Systems (NS): Technology Demonstration Unit (TDU)

Data.gov (United States)

National Aeronautics and Space Administration — The Nuclear Systems Project demonstrates nuclear power technology readiness to support the goals of NASA's Space Technology Mission Directorate. To this end, the...

Symmetric Kullback-Leibler Metric Based Tracking Behaviors for Bioinspired Robotic Eyes.

Science.gov (United States)

Liu, Hengli; Luo, Jun; Wu, Peng; Xie, Shaorong; Li, Hengyu

2015-01-01

A symmetric Kullback-Leibler metric based tracking system, capable of tracking moving targets, is presented for a bionic spherical parallel mechanism to minimize a tracking error function to simulate smooth pursuit of human eyes. More specifically, we propose a real-time moving target tracking algorithm which utilizes spatial histograms taking into account symmetric Kullback-Leibler metric. In the proposed algorithm, the key spatial histograms are extracted and taken into particle filtering framework. Once the target is identified, an image-based control scheme is implemented to drive bionic spherical parallel mechanism such that the identified target is to be tracked at the center of the captured images. Meanwhile, the robot motion information is fed forward to develop an adaptive smooth tracking controller inspired by the Vestibuloocular Reflex mechanism. The proposed tracking system is designed to make the robot track dynamic objects when the robot travels through transmittable terrains, especially bumpy environment. To perform bumpy-resist capability under the condition of violent attitude variation when the robot works in the bumpy environment mentioned, experimental results demonstrate the effectiveness and robustness of our bioinspired tracking system using bionic spherical parallel mechanism inspired by head-eye coordination.

Symmetric Kullback-Leibler Metric Based Tracking Behaviors for Bioinspired Robotic Eyes

Directory of Open Access Journals (Sweden)

Hengli Liu

2015-01-01

Full Text Available A symmetric Kullback-Leibler metric based tracking system, capable of tracking moving targets, is presented for a bionic spherical parallel mechanism to minimize a tracking error function to simulate smooth pursuit of human eyes. More specifically, we propose a real-time moving target tracking algorithm which utilizes spatial histograms taking into account symmetric Kullback-Leibler metric. In the proposed algorithm, the key spatial histograms are extracted and taken into particle filtering framework. Once the target is identified, an image-based control scheme is implemented to drive bionic spherical parallel mechanism such that the identified target is to be tracked at the center of the captured images. Meanwhile, the robot motion information is fed forward to develop an adaptive smooth tracking controller inspired by the Vestibuloocular Reflex mechanism. The proposed tracking system is designed to make the robot track dynamic objects when the robot travels through transmittable terrains, especially bumpy environment. To perform bumpy-resist capability under the condition of violent attitude variation when the robot works in the bumpy environment mentioned, experimental results demonstrate the effectiveness and robustness of our bioinspired tracking system using bionic spherical parallel mechanism inspired by head-eye coordination.

Evaluating physical protection systems of licensed nuclear facilities using systems engineered inspection guidance

International Nuclear Information System (INIS)

Bradley, R.T.; Olson, A.W.; Rogue, F.; Scala, S.; Richard, E.W.

1980-01-01

The Lawrence Livermore National Laboratory (LLNL) and the US Nuclear Regulatory Commission (NRC) Office of Nuclear Regulatory Research (RES) have applied a systems engineering approach to provide the NRC Office of Inspection and Enforcement (IE) with improved methods and guidance for evaluating the physical protection systems of licensed nuclear facilities

Chilean Nuclear Energy Commission dosimetric information system

International Nuclear Information System (INIS)

Guerrero Vallejos, Patricia Andrea

1997-01-01

This thesis discusses the nuclear radiation that people who work with radioactive material is exposed to and its control by the Chilean Nuclear Energy Commission. A full analysis of the System is presented with information about the Commission and the Department of Nuclear and Radiological Safety which runs the System. Ana analysis of the System is presented in order to obtain requirements. Management flow diagrams, the processes involved and current problems experienced by the users are described. A design logic is modeled producing Data Flow Diagrams (DFD). based on this physical design, or, Model of Physical Data, is prepared including tables, attributes, types of data, primary and foreign keys. A description is presented of how the System is implemented, the tools that are used and how the testing phase is carried out. The Dosimetry System meets the criteria for a Software Engineering project, where the basic cycle was used as a working methodology. The System developed supports the dosimetric control of people exposed to radioactive material. (author)

A computer controlled ultrasonic measurement and testequipment for rotation-symmetrical products

International Nuclear Information System (INIS)

Abend, K.; Lang, R.; Schmidt, U.; Schuett, U.; Sterberg, W.

1976-01-01

During production of rotation-symmetrical thin wall precision tubes, dimensions must be measured and the tubes have to be inspected for surface defects. Within the production area of the tubes, several measurement points for different applications are located at different places. The paper describes their on-line connection to a process-computer system

Rings with involution whose symmetric elements are central

Directory of Open Access Journals (Sweden)

Taw Pin Lim

1980-01-01

Full Text Available In a ring R with involution whose symmetric elements S are central, the skew-symmetric elements K form a Lie algebra over the commutative ring S. The classification of such rings which are 2-torsion free is equivalent to the classification of Lie algebras K over S equipped with a bilinear form f that is symmetric, invariant and satisfies [[x,y],z]=f(y,zx−f(z,xy. If S is a field of char ≠2, f≠0 and dimK>1 then K is a semisimple Lie algebra if and only if f is nondegenerate. Moreover, the derived algebra K′ is either the pure quaternions over S or a direct sum of mutually orthogonal abelian Lie ideals of dim≤2.

Improvement of management systems for nuclear facilities

International Nuclear Information System (INIS)

2005-01-01

The area of Quality Management/ Quality Assurance has been changed dramatically over the past years. The nuclear facilities moved from the 'traditional' Quality Assurance approach towards Quality Management Systems, and later a new concept of Integrated Management Systems was introduced. The IAEA is developing a new set of Standards on Integrated Management Systems, which will replace the current 50-C-Q/SG-Q1-Q14 Code. The new set of document will require the integration of all management areas into one coherent management system. The new set of standards on Management Systems promotes the concept of the Integrated Management Systems. Based on new set a big number of documents are under preparation. These documents will address the current issues in the management systems area, e.g. Management of Change, Continuous Improvement, Self-assessment, and Attributes of effective management, etc. Currently NPES is providing a number of TC projects and Extra Budgetary Programmes to assist Member States in this area. The new Standards on Management Systems will be published in 2006. A number of Regulatory bodies already indicated that they would take the new Management System Standards as a basis for the national regulation. This fact will motivate a considerable change in the management of nuclear utilities, requiring a new approach. This activity is suitable for all IAEA Members States with large or limited nuclear capabilities. The service is directed to provide assistance for the management of all organizations carrying on or regulating nuclear activities and facilities

Hardware Realization of Chaos-based Symmetric Video Encryption

KAUST Repository

Ibrahim, Mohamad A.

2013-05-01

This thesis reports original work on hardware realization of symmetric video encryption using chaos-based continuous systems as pseudo-random number generators. The thesis also presents some of the serious degradations caused by digitally implementing chaotic systems. Subsequently, some techniques to eliminate such defects, including the ultimately adopted scheme are listed and explained in detail. Moreover, the thesis describes original work on the design of an encryption system to encrypt MPEG-2 video streams. Information about the MPEG-2 standard that fits this design context is presented. Then, the security of the proposed system is exhaustively analyzed and the performance is compared with other reported systems, showing superiority in performance and security. The thesis focuses more on the hardware and the circuit aspect of the system’s design. The system is realized on Xilinx Vetrix-4 FPGA with hardware parameters and throughput performance surpassing conventional encryption systems.

Radio frequency system for nuclear fusion

International Nuclear Information System (INIS)

Kozeki, Shoichiro; Sagawa, Norimoto; Takizawa, Teruhiro

1987-01-01

The importance of radio frequency waves has been increasing in the area of nuclear fusion since they are indispensable for heating of plasma, etc. This report outlines radio frequency techniques used for nuclear fusion and describes the development of radio frequency systems (radio frequency plasma heating system and current drive system). Presently, in-depth studies are underway at various research institutes to achieve plasma heating by injection of radio frequency electric power. Three ranges of frequencies, ICRF (ion cyclotron range of frequency), LHRF (lower hybrid range of frequency) and ECRF (electron cyclotron range of frequency), are considered promissing for radio frequency heating. Candidate waves for plasma current driving include ECW (electron cyclotron wave), LHW (lower hybrid wave), MSW (magnetic sound wave), ICW (ion cyclotron wave) with minority component, and FW (fast wave). FW is the greatest in terms of current drive efficiency. In general, a radio frequency system for nuclear fusion consists of a radio frequency power source, transmission/matching circuit component and plasma connection component. (Nogami, K.)

Nuclear proliferation and civilian nuclear power: report of the nonproliferation alternative systems assessment program. Volume V. Economics and systems analysis

International Nuclear Information System (INIS)

1979-12-01

This NASAP assessment considers the economics of alternative nuclear reactor and fuel-cycle systems in the light of possible patterns of uranium supply and energy demand, as well as the economic implications of improving the proliferation resistance of the various systems. The assessment focuses on the costs of alternative nuclear technologies and the possible timing of their implementation, based on their economic attractiveness. The objectives of this assessment are to identify when economic incentives to deploy advanced nuclear power systems might exist, to estimate the costs of using technologies that would reduce the risk of proliferation, to assess the impact of major economic uncertainties on the transition to new technologies, and to compare the investments required for alternative systems

From particle in a box to PT -symmetric systems via isospectral deformation

OpenAIRE

Cherian, Philip; Abhinav, Kumar; Panigrahi, P. K.

2011-01-01

A family of PT -symmetric complex potentials is obtained, which is isospectral to free particle in an infinite complex box in one dimension (1-D). These are generalizations to the cosec2 (x) potential, isospectral to particle in a real infinite box. In the complex plane, the infinite box is extended parallel to the real axis having a real width, which is found to be an integral multiple of a constant quantum factor, arising due to boundary conditions necessary for maintaining the PT -symmetry...

PET image reconstruction with rotationally symmetric polygonal pixel grid based highly compressible system matrix

International Nuclear Information System (INIS)

Yu Yunhan; Xia Yan; Liu Yaqiang; Wang Shi; Ma Tianyu; Chen Jing; Hong Baoyu

2013-01-01

To achieve a maximum compression of system matrix in positron emission tomography (PET) image reconstruction, we proposed a polygonal image pixel division strategy in accordance with rotationally symmetric PET geometry. Geometrical definition and indexing rule for polygonal pixels were established. Image conversion from polygonal pixel structure to conventional rectangular pixel structure was implemented using a conversion matrix. A set of test images were analytically defined in polygonal pixel structure, converted to conventional rectangular pixel based images, and correctly displayed which verified the correctness of the image definition, conversion description and conversion of polygonal pixel structure. A compressed system matrix for PET image recon was generated by tap model and tested by forward-projecting three different distributions of radioactive sources to the sinogram domain and comparing them with theoretical predictions. On a practical small animal PET scanner, a compress ratio of 12.6:1 of the system matrix size was achieved with the polygonal pixel structure, comparing with the conventional rectangular pixel based tap-mode one. OS-EM iterative image reconstruction algorithms with the polygonal and conventional Cartesian pixel grid were developed. A hot rod phantom was detected and reconstructed based on these two grids with reasonable time cost. Image resolution of reconstructed images was both 1.35 mm. We conclude that it is feasible to reconstruct and display images in a polygonal image pixel structure based on a compressed system matrix in PET image reconstruction. (authors)