International Nuclear Information System (INIS)

The time-dependent probability distribution of neutrons, precursors and detectrons in a space-independent, low-power, multiplying assembly with a source is developed in the multigroup approximation as forward and backward Kolmogorov equations. The relationship between these as adjoint equations is made explicit in a tensor notation and the equations developed in the generating-function formalism. (author).

Energy Technology Data Exchange (ETDEWEB)

This paper is concerned with the validation of the 3D deterministic neutral-particle transport theory code EVENT for shielding applications. The code is based on the finite element-spherical harmonics (FE-P{sub N}) method which has been extensively developed over the last decade. A general multi-group, anisotropic scattering formalism enables the code to address realistic steady state and time dependent, multi-dimensional coupled neutron/gamma radiation transport problems involving high scattering and deep penetration alike. The powerful geometrical flexibility and competitive computational effort makes the code an attractive tool for shielding applications. In recognition of this, EVENT is currently in the process of being adopted by the UK nuclear industry. The theory behind EVENT is described and its numerical implementation is outlined. Numerical results obtained by the code are compared with predictions of the Monte ...

International Nuclear Information System (INIS)

(Jun 1972). United States Greene, NM Mynatt, FR Las Vegas, Nev. 18 Jun

International Nuclear Information System (INIS)

A multi-group neutron-gamma cross-section library in DTF-IV format is supplemented with electron production matrix to generate a coupled neutron-gamma-electron library. This is realized by estimating the contributions from Compton scattering, pair production and photoelectric effect to the electron production cross-sections. A novel application of this new library, which involves transport of neutrons, gammas and electrons, for estimating the Compton current due to a pulse of radiation in air is discussed.

International Nuclear Information System (INIS)

Three new classes of finite, homogeneous and nonsingular solutions of Einstein's equations which have time-dependent expansion, shear and rotation are presented. The t-constant sections are of Bianchi type IX. The source of these geometries is a fluid which has not been thermalized. (Author).

Science.gov (United States)

This paper considers the time dependent Stefan problem with convection in the fluid phase governed by the Stokes equation, and with adherence of the fluid on the lateral boundaries. The existence of a weak solution is obtained via the introduction of a te...

Energy Technology Data Exchange (ETDEWEB)

No abstract prepared.

Energy Technology Data Exchange (ETDEWEB)

There are two versions of the MORSE multigroup Monte Carlo radiation transport computer code system at Oak Ridge National Laboratory. MORSE-CGA is the most well-known and has undergone extensive use for many years. MORSE-SGC was originally developed in about 1980 in order to restructure the cross-section handling and thereby save storage. However, with the advent of new computer systems having much larger storage capacity, that aspect of SGC has become unnecessary. Both versions use data from multigroup cross-section libraries, although in somewhat different formats. MORSE-SGC is the version of MORSE that is part of the SCALE system, but it can also be run stand-alone. Both CGA and SGC use the Multiple Array System (MARS) geometry package. In the last six months the main focus of the work on these two versions has been on making them operational on workstations, in particular, the IBM RISC 6000 family. A new version of SCALE for workstations is ...

International Nuclear Information System (INIS)

For models with several time-dependent components, generalized entropies can be defined. This is shown for the Bianchi type IX model. We first derive the Cardy-Verlinde formula under the assumption that the first law of thermodynamics is valid. This leads to an explicit expression of the total entropy associated with this type of universe. Assuming the validity of the Cardy entropy formula, we obtain expressions for the corresponding Bekenstein, Bekenstein-Hawking and Hubble entropies. We discuss the validity of the Cardy-Verlinde formula and possible extensions of the outlined procedure to other time-dependent models.

UK PubMed Central (United Kingdom)

BackgroundOver the past decade, many investigators have used sophisticated time series tools for the analysis of genomic sequences. Specifically, the correlation of the nucleotide...Full Text Available

Science.gov (United States)

... Law Parameter 28 Summary 28 6. CIRCULAR VS ANNULAR LASER BEAMS 29 7. HIGH-ENERGY LASER BEAM PROPAGATION THROUGH A ...

UK PubMed Central (United Kingdom)

We propose new method of assessment of histological images for medical diagnostics. 2-D image is preprocessed to form 1-D landscapes or 1-D signature of the image contour and then their complexity is...Full Text Available

UK PubMed Central (United Kingdom)

Background: CD1d belongs to a family of antigen presenting molecules that are structurally and distantly related to the classic major histocompatibility complex class I (MHC I)...Full Text Available

International Nuclear Information System (INIS)

In previous work, on cooling from 300 K to 10 K the elastic moduli for both #alpha#- and #delta#-Pu dropped 30%. This large change may reflect effects of 5f-electron localization. In this work, the elastic moduli at ambient temperature of several Pu-Ga alloys were measured using resonant ultrasound spectroscopy (RUS). The strong temperature dependence of the bulk and shear modulus and the temperature independence of Poisson's ratio was confirmed and the upper temperature limit for #alpha#-Pu was extended to 360 K. Measurements of the time dependence of the shear moduli of Pu and Pu-2.36 at.% Ga were determined with high precision as a function of time and temperature. Using a model for time dependence of point defects, we determined the exponential time constant at ambient temperature for such variations. The low temperature results are consistent with Fluss .

Energy Technology Data Exchange (ETDEWEB)

Neutron and gamma ray energy spectra were measured using an NE-213 scintillator at depths of 7.2, 15.2, and 22.2 cm in a tissue-equivalent phantom which was uniformly irradiated on one face by deuterium--tritium (DT) neutrons. Coupled neutron--gamma ray multigroup discrete-ordinates calculations were performed using semi-infinite slab geometry. These calculations were used to supplement the measured spectra below 1 MeV. Similar calculations were performed to study the perturbation in the phantom due to the detector. The measured and calculated spectra were used to determine the kerma distributions for neutrons and gamma rays at each location. The gamma radiation was determined to contribute more than 10% of the total dose at each depth. The calculated kerma also reveals that a knowledge of the gamma ray spectra below 1 MeV is desirable. Key words: neutron--gamma spectra, spectrometry, kerma distributions, coupled multigroup calculations

International Nuclear Information System (INIS)

The seismic analysis of nuclear island of Daya Bay Nuclear Power Plant (NPP) was just in accordance with the approaches in RCC-G standard for the model M310 in France, in which the simplified impedance matrix method was employed for the consideration of soil's function. In this paper the more sophisticated 3D half-space continuum impedance method based on the Green functions is used to analyze the function of soil. In addition, multi-group of input time histories was used in the seismic response analysis in the existing design and their average of responses for each group was taken as the design basis. The same multi-group of input time histories was used in the seismic response analysis in this study, but the average and enveloped value of responses for each case are calculated respectively to account for the uncertainty of input motions. Focused on the above two issues, the seismic responses of the reactor building are calculated and the ...

International Nuclear Information System (INIS)

Energy conservation and local energy deposition are investigated in the context of coupled-particle (i.e., neutrons, gamma rays, and charged particles) transport analysis. For charged particles, the concept of group splitting the 1 = 0 transfer matrix to ensure both particle and energy conservation is introduced. Although these procedures are more complex than those found in the usual neutron or coupled-neutron gamma-ray problem, they yield a consistent approach for the calculation of local energy deposition.

International Nuclear Information System (INIS)

Shielding calculations for neutron-gamma radiation are usually done by using the full Theory of Transport or the Monte Carlo Techniques. After some works based on the Albedo Method, the shielding calculations for neutron-gamma radiation have a reliable tool with great didactical value which shows its clarity and simplicity for the resolution of cases that involve neutrons and photon shielding in nonmultiplying media. The excellent results of these works have motivated the elaboration and the development of this study that will be presented in this dissertation. The balance of a neutronic current entering a shield of two layers considering the coupling neutron-gamma will be determined by the Albedo Method. The shield will be composed of a layer of iron and another one of manganese with 10 cm of thickness each. The arrays of the materials coefficients will be obtained from the ANISN code. ANISN is a one dimensional deterministic code that is based on transport equation. The final results ...

UK PubMed Central (United Kingdom)

This study examined changes in the degree of positive bias in self-perceptions of previously-diagnosed 8 to 13 year-old children with attention-deficit/hyperactivity disorder (ADHD) (n=513)...Full Text Available

UK PubMed Central (United Kingdom)

The activity of mice in their home cage is influenced greatly by the cycle of light and dark. In addition, home-cage activity shows remarkable time-dependent changes that result in a prominent temporal...Full Text Available

UK PubMed Central (United Kingdom)

Trypanothione reductase (TryR) is a key enzyme involved in the oxidative stress management of the Trypanosoma and Leishmania parasites, which helps to maintain an intracellular reducing environment...Full Text Available

UK PubMed Central (United Kingdom)

How learning and memory is achieved in the brain is a central question in neuroscience. Key to today’s research into information storage in the brain is the concept of synaptic plasticity, a...Full Text Available

International Nuclear Information System (INIS)

To investigate the 2D/1D fusion core analysis method, a 1D neutron transport problem solver, PEACH-ID, is developed. It is a code of method of characteristics (MOC), both the usual fiat-source step characteristics (SC) scheme and linear source (LS) approximation scheme are adopted for tracking calculation along the neutron flying trajectory. Exponential function interpolation table and fission source extrapolation are adopted as two major methods to accelerate the computational process. Numerical results demonstrate that PEACH-1D is accurate and efficient, and the proposed LS scheme is able to handle quite larger mesh division and deserves much more application in the MOC codes. (authors)

Energy Technology Data Exchange (ETDEWEB)

This work describes a procedure for the adaptive time dependent Finite Element Method using an automatic mesh refinement (H-Version) that efficiently reduces estimated errors ( a posteriori) below pre-assigned limits. Classical model problem for steady-state heat transfer are investigated, and the results are compared with the analytical solution. Then some typical time-dependent problem are qualitatively analysed. (author) 10 refs., 7 figs.

International Nuclear Information System (INIS)

For the layout of a pressure suppression system of a light water cooled reactor (boiling water reactor) it is important to know the time dependent behavior of the vent clearing transient after a loss-of-coolant accident for two main reasons: time of the end of the vent clearing transient influences strongly the pressure and temperature maxima in the drywell and wetwell. Time-dependent behavior of the vent clearing transient influences pressure loads in the condensation pool of the wetwell and therefore pressure induced stresses to the structure. The time-dependent behavior of the water masses in the vent pipes and wetwell are described by the basic equations for a nonstationary incompressible friction flow: momentum equation, continuity equation and a correlation for the variation of the state of the gas volume in the wetwell above the water level. After many algebraic operations and integrations along ...

Energy Technology Data Exchange (ETDEWEB)

The Nuclear Data Interface (NDI) code library and data formats are the standards for multigroup nuclear data at Los Alamos National Laboratory. NDI's analysis, design, implementation, testing, integration, and maintenance required a ten person-year and ongoing effort by the Nuclear Data Team. Their efforts provide a unique, contemporary experience in producing a standard component library. In reflection upon that experience at NDI's decennial, we have identified several factors critical to NDI's success: it addressed real problems with appropriate simplicity, it fully supported all users, it added extra value through the code to the raw nuclear data, and its team went the distance from analysis through maintenance. In this report we review these critical success factors and discuss their implications for future standardization projects.

International Nuclear Information System (INIS)

As a contribution to the US/Japan cooperative program in fusion neutronics, we have prepared a library of multigroup neutron cross sections, scattering matrices, and covariances (uncertainties and their correlations). This 74-group library, called COVFILS-2, is being used at Los Alamos and at the University of California at Los Angeles in the sensitivity and uncertainty analysis of the Li_2O integral experiment recently performed at the Fast Neutron Source (FNS) in Japan. Another intended use of this library is in the estimation of the uncertainty in key performance parameters (such as breeding ratio) of conceptual fusion reactors. The 14 materials included in the first version of COVFILS-2 are H, "6Li, "7Li, Be, C, N, O, Na, Al, Si, Cr, Fe, Ni, and Pb.

International Nuclear Information System (INIS)

An outline is given of time-dependent wavepacket methods as applied to calculations of molecular collisions with solid surfaces. The methods reviewed include numerical integration algorithms for the time-dependent Schroedinger equation, semiclassical wavepacket treatments, and approximations that treat some of the degrees-of-freedom quantum-mechanically and others classically. The computational and numerical characteristics of these methods are discussed, with emphasis on their particular advantages and relevance in the context of certain molecule/surface scattering problems. For the semiclassical and mixed quantal-classical treatments, the approximation errors and their physical origins are discussed. For the quantum wavepacket techniques a numerical error analysis is presented. The computational efficiency of the various algorithms is considered and examined in the context of several applications. The main focus is on diffractive scattering ...

CERN Document Server

We present a description of nuclear spontaneous fission, and generally of quantum tunneling, in terms of instantons - periodic imaginary-time solutions to time-dependent mean-field equations - that allows for a comparison with more familiar and used generator coordinate (GCM) and adiabatic time-dependent Hartree-Fock (ATDHF) methods. It is shown that the action functional whose value for the instanton is the quasiclassical estimate of the decay exponent fulfils the minimum principle when additional constraints are imposed on trial fission paths. In analogy with mechanics, these are conditions of energy conservation and the velocity-momentum relations. In the adiabatic limit the instanton method reduces to the time-odd ATDHF equation, with collective mass including the time-odd Thouless-Valatin term, while the GCM mass completely ignores velocity-momentum relations. This implies that GCM inertia generally overestimates instanton-related decay ...

Science.gov (United States)

Standard Practice for Military Marking. MIL-STD-130. K. 1/15/00. Identification Marking of U.S. Military Property. MIL-STD-2073-1 D. Notice 1. 12/15/99. 05/10/ 02 ...

UK PubMed Central (United Kingdom)

The majority of diseases in the retina are caused by genetic mutations affecting the development and function of photoreceptor cells. The transcriptional networks directing these processes are regulated...Full Text Available

International Nuclear Information System (INIS)

Russian 1986. p. 334. USSR Burtebaev, NT Dujsebaev, AD Sadkovskij,

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In the present work, we describe application of binary pseudo-random gratings (BPRG) and arrays (BPRA) as effective 1D and 2D test surfaces suitable for calibration of different surface profilometers, including a number of interferometric microscopes and scatterometers.

UK PubMed Central (United Kingdom)

Several investigations suggested abnormalities in circadian rhythms are related to the pathophysiology of psychiatric disorders, including drug addiction. Recently, orphan nuclear receptor rev-erb alpha...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

The principal mathematical tools frequently available for calculations in Nuclear Engineering, including coupled neutron-gamma radiations shielding problems, involve the full Transport Theory or the Monte Carlo techniques. The Multigroup Albedo Method applied to shieldings is characterized by following the radiations through distinct layers of materials, allowing the determination of the neutron and gamma fractions reflected from, transmitted through and absorbed in the irradiated media when a neutronic stream hits the first layer of material, independently of flux calculations. Then, the method is a complementary tool of great didactic value due to its clarity and simplicity in solving neutron and/or gamma shielding problems. The outstanding results achieved in previous works motivated the elaboration and the development of this study that is presented in this dissertation. The radiation balance resulting from the incidence of a neutronic stream into a shielding ...

International Nuclear Information System (INIS)

The upper range of the requirement for methionine plus cystine in healthy adults was proposed in 1985 by FAO/WHO/UNU to be 13 mg.kg body wt-1.d-1. To explore the validity of this estimate, five healthy, young adult men were given for 7 d a diet based on an L-amino acid mixture supplying 13 mg methionine.kg-1.d-1 (87 mumol.kg-1.d-1) without cystine. Constant intravenous infusions of L-[2H3-methyl-1-13C]methionine were given on days 5 and 7 while subjects were in the fed and postabsorptive states, respectively. Estimates were made of methionine oxidation, and daily methionine balance was derived from the intake-oxidation data. For the five subjects, methionine balances were -0.9, +0.7, +3.5, -3.1, and -3.8 mg kg-1.d-1, or -6, +5, +23, -21, and -26 mumol.kg-1.d-1. These findings ...

CERN Document Server

We apply the potential force estimation method to artificial time series of market price produced by a deterministic dealer model. We find that dealers' feedback of linear prediction of market price based on the latest mean price changes plays the central role in the market's potential force. When markets are dominated by dealers with positive feedback the resulting potential force is repulsive, while the effect of negative feedback enhances the attractive potential force.

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Experimentally it is found that at constant temperature the order-parameter relaxation time, tausub(..delta..), decreases with increasing power of the microwaves, coupled into a superconducting strip. If the same increase in critical current, that corresponds with a given power of the microwaves, is obtained by lowering the temperature, the decrease in tausub(..delta..) is smaller. This reflects the fact that quasiparticles are removed more efficiently from the gap edge by microwaves than by lowering the temperature in equilibrium. A modified time-dependent Ginzburg-Landau equation is shown to describe these results adequately.

CERN Document Server

Recently, Guo and Xia introduced low complexity decoders called Partial Interference Cancellation (PIC) and PIC with Successive Interference Cancellation (PIC-SIC), which include the Zero Forcing (ZF) and ZF-SIC receivers as special cases, for point-to-point MIMO channels. In this paper, we show that PIC and PIC-SIC decoders are capable of achieving the full cooperative diversity available in wireless relay networks. We give sufficient conditions for a Distributed Space-Time Block Code (DSTBC) to achieve full diversity with PIC and PIC-SIC decoders and construct a new class of DSTBCs with low complexity full-diversity PIC-SIC decoding. We also show that almost all known full-diversity PIC/PIC-SIC decodable codes constructed for point-to-point MIMO channels can be used as full-diversity PIC/PIC-SIC decodable DSTBCs in relay networks. The proposed DSTBCs with low complexity, full-diversity PIC/PIC-SIC decoding achieve higher rates (in complex symbols per channel use) than the ...

International Nuclear Information System (INIS)

The author have prepared a new, fusion-oriented library of multigroup neutron cross sections, scattering matrices, and covariances (uncertainties and correlations). The 74-group library, called COVFILS-2, has been used, or will be used, by neutronics groups at Los Alamos National Lab. (LANL) at the University of California at Los Angeles, and at the Swiss Federal Institute for Reactor Research in the sensitivity and uncertainty analysis of fusion-relevant integral experiments such as the Li_2O experiment performed at the Fast Neutron Source Facility in Japan and the Lithium breeding module experiment planned at the LOTUS facility in Lausanne, Switzerland. Another intended use of this library is in the estimation of the uncertainty in key performance parameters (such as the breeding ratio) of conceptual fusion reactors. The 14 materials included in the first version of COVFILS-2 are hydrogen, "6Li, "7Li, beryllium, carbon, nitrogen, oxygen, sodium, aluminum, ...

International Nuclear Information System (INIS)

Full text: The principal nuclear design tools available to the shielding designer include diffusion approximation, transport theory, and Monte Carlo techniques. Full transport theory or Monte Carlo methods are routinely used for shielding analyses, where penetration investigations are more sensitive to directional aspects. However, the aim of this paper is to illustrate the coupled neutron-gamma Albedo method particularly as applied to problems of shielding analysis. The multigroup Albedo method is applied to coupled neutron-gamma radiations considering 'n' neutron energy groups and 'g' gamma energy groups to estimate the probabilities of transmission through, absorption in, and reflection from shieldings composed by multiple material layers, 'm' slabs, in which no fission occurs. In this study, these energy groups were selected in order to minimize upscattering effects of the radiation from lower energy groups to higher energy groups. However, neutrons of all ...

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A non-linear analysis of a Cerenkov maser is presented. The system consists of a ring configuration of a cylindrical waveguide filled with a dielectric material. A single transverse-magnetic mode is assumed to propagate in the system. A low-density pencil electron beam travels in part of the ring, confined by a strong axial magnetic field. Using the single-particle description for the beam and the wave equation for the field, we obtain a set of two coupled non-linear differential equations describing the slowly varying amplitude and phase of the electromagnetic mode. The gain per path is assumed to be small and the spatial growth of the field is neglected. The resulting time dependent amplitude includes the exponential gain of the linear stage and the saturation to its maximum value. The time dependent frequency is also calculated. The two equations are combined to a single Van Der Pol equation with a ...

CERN Document Server

CDS Invenio is the web-based integrated digital library system developed at CERN. It is a suite of applications which provides the framework and tools for building and managing an autonomous digital library server. Within this framework, the goal of this project is to implement new ranking methods based on the bibliographic citation graph extracted from the CDS Invenio database. As a first step, we implemented the Citation Count as a baseline ranking method. The major disadvantage of this method is that all citations are treated equally, disregarding their importance and their publication date. To overcome this drawback, we consider two different approaches: a link-based approach which extends the PageRank model to the bibliographic citation graph and a time-dependent approach which takes into account time in the citation counts. In addition, we also combined these two approaches in a hybrid model based on a time-dependent PageRank. In the ...

Science.gov (United States)

A 100-bit slitlike aperture array spatial light modulator has been developed using 8.8/65/35 PLZT for a high-bit-density 1-D hologram memory. The most desirable characteristics, such as distortion-free diffraction-limited Fourier transform patterns and good uniformity of displayed bit patterns over 100 bits, have been realized. The lowest SNR was 86, and rise time and fall time have been 30 microsec and 8 microsec, respectively, at 190-V halfwave voltage. One-dimensional holographic storage experiments have been successfully performed using this PLZT spatial light modulator. PMID:20216813

British Library Electronic Table of Contents (United Kingdom)

Most gas dynamic computations in industrial ducts are done in one dimension with cross-section-averaged Euler equations. This poses a fundamental difficulty as soon as geometrical discontinuities are present. The momentum equation contains a non-conservative term involving a surface pressure integral, responsible for momentum loss. Definition of this integral is very difficult from a mathematical standpoint as the flow may contain other discontinuities (shocks, contact discontinuities). From a physical standpoint, geometrical discontinuities induce multidimensional vortices that modify the surface pressure integral. In the present paper, an improved 1D flow model is proposed. An extra energy (or entropy) equation is added to the Euler equations expressing the energy and turbulent pressure ...

International Nuclear Information System (INIS)

A new acquisition and evaluation procedure has been introduced for the measurement of time-dependent processes in gamma-ray spectrometry, in order to extract more information, including half-lives, from the data recorded during acquisition and to enable a more comprehensive analysis of the results. These advanced, off-line data evaluation techniques improve the selectivity and the background subtraction and make it possible to estimate the important analytical parameters (e.g., half-lives) more accurately than with the usual decay curve fitting method. (author)

British Library Electronic Table of Contents (United Kingdom)

We apply the group theory to Kadomtsev-Petviashvili-Burgers (KPBII) equation which is a natural model for the propagation of the two-dimensional damped waves. In correspondence with the generators of the symmetry group allowed by the equation, new types of symmetry reductions are performed. Some new exact solutions are obtained, which can be in the form of solitary waves and periodic waves. Specially, our solutions indicate that the equation may have time-dependent nonlinear shears. Such exact explicit solutions and symmetry reductions are important in both applications and the theory of nonlinear science.

Energy Technology Data Exchange (ETDEWEB)

Modified Ostwald ripening theory is used to calculate the time evolution of the size distribution function of extended end-of-range defects in ion implanted silicon. This allows the authors to compare the time dependent self-interstitial supersaturation during post-implantation annealing in the presence of Frank-type stacking faults with that in the presence of {l_brace}311{r_brace}-defects. It is shown that the latter affect self-interstitial concentrations up to the point where they dissolve whereas the former are irrelevant from the point of view of transient enhanced diffusion.

Science.gov (United States)

Self-magnetically insulated, high-voltage transmission lines are used in inertial confinement fusion particle accelerators in order to transmit power from the vacuum insulator to the diode. This paper describes a time-dependent 2-D code (MITL) for calculating (for planar or triplate geometries) the motion of test electrons through the tapered input or output convolutes of such lines. MITL results show that the electron canonical momentum in the direction of the flow changes as the electron passes through the convoluted geometry; it is suggested that these electrons lead to losses observed in long self-magnetically insulated lines.

International Nuclear Information System (INIS)

Effects of the rapid early-in-life expansion of metal fuel were measured in an irradiation experiment in the Fast Flux Test Facility (FFTF). This important performance/design information was obtainable through the unique combination of a dimensionally stable FFTF oxide core and the calibrated proximity instrumentation associated with the test. These results delineate the time dependence of metal-fuel swelling and provide quantitative estimates of the magnitude of axial fuel swelling in full-length metal-fuel assemblies. Final posttest examination results will define actual fuel column growth levels.

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This paper reviews and elaborates on the issue of the dilaton transformation under the usual {tau} {yields} {alpha}{prime}/{tau} target space duality and its non-static generalization (or {sigma}-model duality). It is found that the transformation law {tau} {yields} {alpha}{prime}/{tau}, {phi} {yields} {phi} In ({tau}/{alpha}{prime}) which guarantees duality at the one-loop {sigma}-model level should be modified at two (and higher) loop order. The non-static duality is illustrated on the example of cosmological solutions in D {ge} 2 with time-dependent radii of space torus.

Science.gov (United States)

Unsteady impinging jets are systematically controlled with respect to their time dependence in order to investigate the influence of unsteadiness on the heat transfer performance. This is achieved by a special mass flow control device, which allows almost arbitrary shapes of unsteadiness to be imposed onto the impinging jet. Three different standard signals (sinusoidal, triangular, rectangular) and two specially designed signals are applied and their influence on heat transfer is determined in terms of an enhancement factor. Heat transfer augmentation up to 30% was found and could be physically explained with the help of PIV and hot-wire measurements of the flow field.

British Library Electronic Table of Contents (United Kingdom)

The chemical reaction effect on an unsteady magnetohydrodynamic (MHD) flow past a semi-infinite vertical porous plate with viscous dissipation is analyzed. The governing equations of motion, energy, and species are transformed into ordinary differential equations (ODEs) using the time dependent similarity parameter. The resultant ODEs are then solved numerically by a finite element method. The effects of various parameters on the velocity, temperature, and concentration profiles are presented graphically, and the values of the skin-friction, Nusselt number, and Sherwood number for various values of physical parameters are presented through tables.

Energy Technology Data Exchange (ETDEWEB)

In an ionization chamber with the electric field parallel to the particle trajectories, the time dependence of the anode signal contains all the information about the energy and the nuclear charge of the ionizing particle. By proper pulse shaping with a long and a short time constant the total ionization charge and the ionization charge integrated around the Bragg maximum, respectively, can be obtained. The former signal is proportional to the total energy, whereas the latter allows the nuclear charge to be deduced directly. An energy resolution of 0.4% and a Z resolution ..delta..Z/Z = 1/82 was achieved for 130 MeV /sup 32/S ions and argon-methane as the stopping medium.

Science.gov (United States)

COMHOM/TANKF/ Fl ,F8 ,F3 ,F4,F5 ,F6,F7 ,F8,F9 ,F1D,F11 ,FI2,F13 ,F14. ...... The cumulative average learning curve exponent ...

CERN Document Server

We derive the expression for spontaneous emission rate in finite one-dimensional photonic crystal with arbitrary defects using the effective resonator model to describe electromagnetic field distributions in the structure. We obtain explicit formulas for contributions of different types of modes, i.e. radiation, substrate and guided modes. Formal calculations are illustrated with a few numerical examples, which demonstrate that the application of effective resonator model simplifies interpretation of results.

Science.gov (United States)

...prosthesis) Anatomical loss near hip (preventing use of prosthesis) Anatomical loss or loss of use below elbow M Codes M-1 a, b, or c, 38 CFR 3.350 (c)(1)(i) L Codes L-1 d, e, f, or g, 38 CFR 3.350(b)...

International Nuclear Information System (INIS)

A new method for kinetic experiments with neutrons is described. This method combines the conventional triple-axis neutron spectroscopy with relaxation-type experiments. Whereas the former method yields information about the microscopic dynamics of solids, the latter provides macroscopic relaxation times. The combination of both methods allows to determine the microscopic mechanism of relaxation processes. The time-resolved triple-axis spectroscopy is limited to reversible processes and to time scales from 10"-"3 to 10"4 s. Typical applications are the kinetics of phase transformations (structural and dynamical changes), kinetics of domain distributions, kinetics of (spinodal) decomposition, reversible solid state reactions, time-dependent occupation of phonon states or phonon lifetimes. (orig.).

International Nuclear Information System (INIS)

The Advanced Loose Parts monitoring System (ALPS), is installed in each Unit of Paks NPP. Its characteristics and some interesting results are presented. Wavelet analysis is being introduced to data evaluation techniques. The short-time Fourier transform and the continuous wavelet transform techniques have been used to present the time signal in a time-frequency and time-scale plane. Characteristic frequencies of the physical acoustic system and the growing frequencies of spectrum components during the start-up of the main coolant pumps are clearly seen on those pictures. The newly applied wavelet coherence promises to find new oscillation in the pair of signals, which remain hidden in time-dependent autospectra. (author)

British Library Electronic Table of Contents (United Kingdom)

A novel difunctional acylhydrazone has been synthesized by the reaction of 5-methylisoxazole-4-carboyl hydrazine with benzaldehyde and characterized by X-ray crystallography and spectroscopy. The obtained results demonstrate the crystal belongs to triclinic, space group Formula Not Shown . Moreover, the spectroscopic properties were evaluated through density functional theory (DFT) and time-dependent density functional theory (TD DFT) calculations. The results reveal that UV-Vis absorption peaks at 194, 217.5 and 290.5nm are mainly attributed to (p, p)p*, partly (p, p)p* and partly pp*, and predominantly pp*, respectively, with intraligand charge-transfer transition (ILCT) character. The fluorescence emission peak at 485.96nm should be assigned to ILCT. In addition, the results of antibact...

Energy Technology Data Exchange (ETDEWEB)

Singlet-singlet and triplet-triplet absorption spectra of a series of methyl-alloxazines were calculated using the time-dependent density-functional theory approach and compared to experimental results. The B3LYP functional provides good correlation between experimental and theoretical results, given that solvent effects are disregarded in the present calculations. Substituent and solvent dependences of the lowest, closely spaced, n,{pi}* and {pi},{pi}* excited state energies are discussed, their order being of consequence in determining the non-radiative decay rates and thus emission quantum yields and lifetimes. The high quantum yields of singlet oxygen formation indicate that the triplet state is formed by efficient intersystem crossing from the first singlet excited state.

British Library Electronic Table of Contents (United Kingdom)

The shock stand-off distance of a spherical model flying with transonic speeds is determined through numerical simulations. The model decelerates due to drag forces caused by the pressure and viscous shear stress at the model surface. Two-dimensional axisymmetric numerical codes with numerical grids fixed to the flying spherical model are used in the simulations. Numerically determined shock stand-off distances are compared with experimental data obtained in a previous study as well as with those obtained in our ballistic-range experiments. The numerical results and the experimental data are found to be in good agreement. In addition, the time-dependent shock stand-off distance of a decelerating model is investigated.

International Nuclear Information System (INIS)

The paper gives an introduction to reliability assessment of reliquefaction systems for boil-off gas (BOG) on LNG carriers with focus on redundancy optimization and maintenance strategies. The reliability modeling is based on a time-dependent Markov approach. Four different system options are studied, with varying degree of redundancy. Failures in the reliquefaction system may require flaring of the BOG, and the associated cost is compared with the cost of introducing redundancy and the cost of onboard maintenance. A model for maintenance optimization is developed and exemplified on a main unit of the reliquefaction system. Reliability and maintenance cost data for reliquefaction systems on LNG ships are very scarce. The input data have been collected from the best available data sources and adjusted by expert judgement. A tailor-made computer program has been developed and may be supplied to interested readers.

Energy Technology Data Exchange (ETDEWEB)

Recently it was demonstrated that long-lived quantum coherence exists during excitation energy transport in photosynthesis. It is a valid question up to which length, time and mass scales quantum coherence may extend, how one may detect this coherence and what, if any, role it plays in the dynamics of the system. Here we suggest that the selectivity filter of ion channels may exhibit quantum coherence, which might be relevant for the process of ion selectivity and conduction. We show that quantum resonances could provide an alternative approach to ultrafast two-dimensional (2D) spectroscopy to probe these quantum coherences. We demonstrate that the emergence of resonances in the conduction of ion channels that are modulated periodically by time-dependent external electric fields can serve as signatures of quantum coherence in such a system. Assessments of experimental feasibility and specific paths towards the experimental realization of such experiments are ...

Science.gov (United States)

An optimal deployment pattern of flux mapping detectors for a Canada uranium-deuterium (CANDU)-600 pressurized heavy water reactor (PHWR) is determined by obtaining an optimal feedback relationship between flux measurements and zone controllers. The reactor core is modeled with a time-dependent two-group, two-dimensional diffusion equation, and flux perturbation are expressed by model expansions. The modal expansion coefficients are used as elements of the state vector representing the system dynamics. An optimal feedback matrix connecting the flux measurement vector to the control vector is derived by minimizing a quadratic performance index involving both the state and control vectors. We obtain the detector effectiveness in terms of the optimal feedback matrix and determine optimal detector locations for the Wolsung Unit 1 reactor in Korea. We have tested the methodology through evaluation of flux maps generated through the CANDU flux mapping system.

Science.gov (United States)

We show that accretion disks, both in the subcritical and supercritical accretion rate regime, may exhibit significant amplitude luminosity oscillations. The luminosity time behavior has been obtained by performing a set of time-dependent 2D SPH simulations of accretion disks with different values of ? and accretion rate. An explanation of this luminosity behavior is proposed in terms of limit-cycle instability: the disk oscillates between a radiation pressure dominated configuration (with a high luminosity value) and a gas pressure dominated one (with a low luminosity value). The origin of this instability is the difference between the heat produced by viscosity and the energy emitted as radiation from the disk surface (the well-known thermal instability mechanism). We support this hypothesis showing that the limit-cycle behavior produces a sequence of collapsing and refilling states of the innermost disk region.

Energy Technology Data Exchange (ETDEWEB)

The mass and charge distributions in an unseparated mix of fission product nuclei from thermal-neutron fission of /sup 242m/Am were studied through semiconductor gamma-ray spectrometry. Samples of the fissionable material under study were irradiated in a vertical irradiation tube of the MIFI IRT research reactor. Following irradiation, measurements were made on aperture-calibrated semiconductor detectors. For broader identification of fission fragment nuclides three experiments were conducted that differed substantially in irradiation duration. The spectrum of gamma radiation from the mix of fission products and the time dependences of count rate at total absorption peaks were analyzed on SM-4 and Iskra-226 computers. The values of yields obtained were compared with data of investigations conducted earlier with other experimental methods, and also with the results of calculations.

International Nuclear Information System (INIS)

A noninvasive method is described for estimating local cerebral blood flow (LCBF) and local partition coefficients by means of computed tomographic scanning during inhalation of 30% stable xenon gas in oxygen. Time-dependent xenon concentrations in arterial blood and brain tissue during the wash-in and washout phases are used to calculate partition coefficients and LCBF values by means of a least-squares curve-fitting analysis. Control values for partition coefficient and LCBF obtained from control subjects with minor head trauma in the chronic stage were compatible with those in several past reports, and reproducibility was satisfactory. The theoretic grounds underlying this new method of curve-fitting analysis are discussed.

Science.gov (United States)

We show that accretion disks, both in the subcritical and supercritical accretion rate regime, may exhibit significant amplitude luminosity oscillations. The luminosity time behavior has been obtained by performing a set of time-dependent 2D SPH simulations of accretion disks with different values of ? and accretion rate. An explanation of this luminosity behavior is proposed in terms of limit-cycle thermal instability: the disk oscillates between a radiation pressure dominated configuration (with a high luminosity value) and a gas pressure dominated one (with a low luminosity value). We support this hypothesis showing that the limit-cycle behavior produces a sequence of collapsing and refilling states of the innermost disk region.

International Nuclear Information System (INIS)

Denting phenomenon as experienced in PWR steam generators has been investigated in the laboratory of Monel-400 tubes and C-steel baffles combination. Isothermal corrosion tests have been carried out by exposing capsules, containing a crevice between Monel-400 tubes and C-steel plugs, in plausible corrodents at 300"0C. Results indicated that the denting phenomenon is strongly influenced by the chloride content in the solution. In addition, it is a time dependent process. Stress exerted on the tubes by the growth of corrosion product on the outside surface of C-steel plugs are enough to deform the Monel tubes. The results have been discussed on the basis of accelerated corrosion of C-steel by hydrolyzable metal chlorides. (author).

Energy Technology Data Exchange (ETDEWEB)

UO/sub 2/ definitely leaked past the O-ring in three of the tests confirming the major results of the previous work. Continuous leakage at these levels may require additional precautions under present regulatory policies. The mechanism and the time and particle size dependence for the leakage are not known, but there is some indication leakage is more likely at low temperatures. It is possible leakage is due to movement of the O-ring during temperature or pressure cycling at the beginning or end of a test. The radiotracer method involves less labor and is much less susceptible to contamination than the previous method. Future work will investigate leakage past lubricated O-rings and time dependence of leakage. 1 reference, 1 table.

International Nuclear Information System (INIS)

The antisymmetric many-body trial state which describes a system of interacting fermions is parametrized in terms of localized wave packets. The equations of motion are derived from the time-dependent quantum variational principle. The resulting fermionic molecular dynamics (FMD) equations include a wide range of semi-quantal to classical physics extending from deformed Hartree-Fock theory to newtonian molecular dynamics. Conservation laws are discussed in connection with the choice of the trial state. The model is applied to heavy-ion collisions with which its basic features are illustrated. The results show a great variety of phenomena including deeply inelastic collisions, fusion, incomplete fusion, fragmentation, neck emission, promptly emitted nucleons and evaporation. ((orig.)).

CERN Document Server

We consider dimensional reduction techniques for the Liouville-von Neumann equation for the evaluation of the expectation values in a mixed quantum system. In applications such as nuclear spin dynamics the main goal for simulations is being able to simulate a system with as many spins as possible, for this reason it is very important to have an efficient method that scales well with respect to particle numbers. We describe several existing methods that have appeared in the literature, pointing out their limitations particularly in the setting of large systems. We introduce a method for direct computation of expectations via Chebyshev polynomials (DEC) based on evaluation of a trace formula combined with expansion in modified Chebyshev polynomials. This reduction is highly efficient and does not destroy any information. We demonstrate the practical application of the scheme for a nuclear spin system and compare with several alternatives, focusing on the performance of the various ...

Energy Technology Data Exchange (ETDEWEB)

The delayed neutrons from neutron-induced fission in /sup 232/U, /sup 237/Np, /sup 238/Pu, /sup 241/Am, /sup 242/Am/sup m/, /sup 245/Cm, and /sup 249/Cf were studied for the first time; those from /sup 232/Th, /sup 233/U, /sup 235/U, /sup 238/U, /sup 239/Pu, /sup 241/Pu, and /sup 242/Pu were measured again. The data were used to develop an expression for the prediction of the absolute delayed neutron yield, and the prediction of delayed neutron emission with time. This approach accurately predicts observed delayed neutron yields and decay characteristics. A fission product yield model was used in conjunction with delayed neutron emission probability to analytically predict delayed neutron characteristics. The results of this analysis are in excellent agreement with experimental values.

Energy Technology Data Exchange (ETDEWEB)

We study D-branes in a two-dimensional lorentzian orbifold R{sup 1,1}/{gamma} with a discrete boost {gamma}. This space is known as Misner or Milne space, and includes big crunch/big bang singularity. In this space, there are D0-branes in spiral orbits and D1-branes with or without flux on them. In particular, we observe imaginary parts of partition functions, and interpret them as the rates of open string pair creation for D0-branes and emission of winding closed strings for D1-branes. These phenomena occur due to the time-dependence of the background. Open string 2{yields}2 scattering amplitude on a D1-brane is also computed and found to be less singular than closed string case.

International Nuclear Information System (INIS)

The dynamics of a cluster-type system formed by constant total number of molecules, M, is studied when clusters change their sizes by nearest-size transitions (the Szilard model) with time-dependent boundary conditions and non-zero initial cluster size distribution. We compare these results to those reported previously, when non-stationary cluster size distribution was considered under the condition that only monomers are present in the system at the initial moment t=0, and describe the effect of arbitrary pre-existing clusters on the time evolution of the interacting clusters with different sizes, n. The average group size problem is also solved, and the process of relaxation in the system is studied. authors)

British Library Electronic Table of Contents (United Kingdom)

Measurement of serum biochemical parameters in response to metal exposures can be especially useful to help identify target organs of toxicity as well as the general health status of animals. Oreochromis niloticus were exposed to 5.0?mg/L?Zn, 1.0?mg/L?Cd, and 5.0?mg/L?Zn?+?1.0?mg/L?Cd mixture for 7 and 28?days, and alterations in serum enzyme activities and ion levels were measured. Significant changes in all the biochemical parameters were found to be time dependent. Following metal exposure, alkaline phosphatase activity was elevated at both exposure periods. No changes in activities of lactate dehydrogenase and lipase were observed in response to single or combined Zn and Cd exposure at 7?days while they increased at 28?days. Fish exposed to metals showed a decrease in cholinesterase ac...

British Library Electronic Table of Contents (United Kingdom)

The present investigation is concerned with the effect of Hall currents on boundary layer flow, and heat and mass transfer of an electrically conducting fluid over an unsteady stretching sheet in the presence of a strong magnetic field. The electron-atom collision frequency is assumed to be relatively high, so that the Hall effect is assumed to exist, while the induced magnetic field is neglected. The governing time-dependent boundary layer equations for momentum, thermal energy, and concentration are reduced using a similarity transformation to a set of coupled ordinary differential equations. The similarity ordinary differential equations are then solved numerically by the successive linearization method together with the Chebyshev pseudo-spectral collocation method. Effects of the Prand...

International Nuclear Information System (INIS)

The published literature is reviewed and supplemented by current information from the author's laboratory, to show the influence of various compositional, heat treatment and thermomechanical factors on the structural characteristics of Alloy 800. The features discussed include carbon, aluminium, titanium and boron, solution treatment, ageing treatments with and without applied strain, and cold working. Examples of the aspects reviewed include the effect of heat treatment and service or testing temperature on the austenite grain size, and the relative importance of M_2_3C_6 and TiC, the influence of carbon level on gamma prime, the effect of residual or steady stress combined with time at temperature on changes in carbide or gamma prime morphology, and on the appearance of sigma or other intermetallic phases. The questions posed by these features are discussed generally, in terms of their effect on the mechanical properties at ambient and elevated temperatures and on the ...

International Nuclear Information System (INIS)

For the first time a comprehensive level and decay scheme has been obtained for a T=(5/2) nucleus in the s-d shell ("2"7Na) by using a radioactive beam and target. Particle-#gamma# and p-#gamma#-#gamma# coincidences were measured following the "1"4C("1"4C,p#gamma#)"2"7Na reaction at E_l_a_b=22 MeV. The results do not support an inversion of the 2s_1_/_2 and 1d_5_/_2 orbitals, as previously proposed for T_z#>=#3, but they do suggest an increased N=16 gap between the 2s_1_/_2 and 1d_3_/_2 orbitals due to the neutron excess. A consistent interpretation of the level scheme in terms of the s-d shell model using the USD Hamiltonian is possible below 4 MeV, but differences increase at higher excitation energies. Another interpretation is that the influences of both the p_1_/_2 and f_7_/_2 intruder orbitals increase simultaneously with increasing T, an effect not included in the USD Hamiltonian.

Science.gov (United States)

The paper deals with the modeling and the development of a numerical procedure for the analysis of shape-memory alloy (SMA) elements in order to predict the main features of SMA devices. A 3D SMA model in the framework of small strain theory is developed starting from the thermo-mechanical model proposed by Souza et al. (Eur J Mech A/Solids 17:789-806, 1998) and modified by Auricchio and Petrini (Int J Numer Methods Eng 55:1255-1284, 2002). The aim of this paper is to propose some more modifications to the original model, to derive its consistent 1D formulation, to clarify the mechanical meaning of the material parameters governing the constitutive model. A robust time integration algorithm is developed in the framework of the finite element method and a new beam finite element is proposed. Some numerical applications and a comparison with experimental data available in literature are carried out in order to assess the ability of the proposed ...

International Nuclear Information System (INIS)

We investigate some aspects of the radiation damage mechanisms in biomolecules, focusing on the modelling of resonant fragmentation caused by the attachment of low-energy electrons (LEEs) initially ejected by biological tissues when exposed to ionizing radiation. Scattering equations are formulated within a symmetry-adapted, single-center expansion of both continuum and bound electrons, and the interaction forces are obtained from a combination of ab initio calculations and a nonempirical model of exchange and correlation effects developed in our group. We present total elastic scattering cross-sections and resonance features obtained for the equilibrium geometries of glycine, alanine, proline and valine. Our results at those geometries of the target molecules are briefly shown to qualitatively explain some of the fragmentation patterns obtained in experiments. We further carry out a one-dimensional (1D) modeling for the dynamics of ...

International Nuclear Information System (INIS)

The thermal performance monitoring and optimization system TEMPO is developed at the OECD Halden Reactor Project. The system supports staff of nuclear power plants in identification and correction of problems, which cause small decreases in plant efficiency but which may lead to significant economical losses. The system-wide physical model consists of mathematical description of individual components, such as the reactor, the pumps, the heat exchangers, or the turbines, etc. TEMPO code has recently been extended with new steam generator (SG) models. The present paper summarizes the thermal-hydraulic modelling aspects of the vertical and the horizontal SG. The heat balance equations and their solution are shown with the appropriate initial and boundary conditions. The method of the calculation of the pressure losses are also introduced. The vertical SG model is based on a U-tube structure and treated as a 1D flow channel. The horizontal approach ...

Energy Technology Data Exchange (ETDEWEB)

The feasibility of removing petroleum hydrocarbons from oil fields produced waters using biological treatment was evaluated under laboratory and field conditions. Based on previous laboratory studies, a field-scale prototype system was designed and operated over a period of four months. Two different sources of produced waters were tested in this field study under various continuous flow rates ranging from 375 1/D to 1,800 1/D. One source of produced water was an open storage pit; the other, a closed storage tank. The TDS concentrations of these sources exceeded 50,000 mg/l; total n-alkanes exceeded 100 mg/l; total petroleum hydrocarbons exceeded 125 mg/l; and total BTEX exceeded 3 mg/l. Removals of total n-alkanes, total petroleum hydrocarbons, and BTEX remained consistently high over 99%. During these tests, the energy costs averaged $0.20/bbl at 12 bbl/D.

International Nuclear Information System (INIS)

The error estimation for calculated quantities relies on nuclear data uncertainty information available in the basic nuclear data libraries such as the U.S. Evaluated Nuclear Data File (ENDF/B). The uncertainty files (covariance matrices) in the ENDF/B library are generally obtained from analysis of experimental data. In the resonance region, the computer code SAMMY is used for analyses of experimental data and generation of resonance parameters. In addition to resonance parameters evaluation, SAMMY also generates resonance parameter covariance matrices (RPCM). SAMMY uses the generalized least-squares formalism (Bayes' method) together with the resonance formalism (R-matrix theory) for analysis of experimental data. Two approaches are available for creation of resonance-parameter covariance data. (1) During the data-evaluation process, SAMMY generates both a set of resonance parameters that fit the experimental data and the associated resonance-parameter covariance matrix. (2) For ...

International Nuclear Information System (INIS)

The activation aspects of pure fusion and hybrid fusion technology is studied to assess the radioactive safety of various fusion concepts including tokamak pure fusion, fissile fuel producing hybrid and radio waste transmuting hybrid. The activation properties of breeding, coolant and structural materials in fusion reactors might be quite different from those in fission reactors because of the high energy D-T fusion neutrons from the fusion cores. A study on the involved activation reactions and the uncertainties of the associated nuclear cross-sections is carried. The activation properties of various first wall concepts and blanket concepts are discussed. The radioactive inventory during the operation lifetime and the potential hazard of the radioactive nuclides with respect to near term (reprocessing) and long term (waste disposal) aspects are calculated, with reference to ITER/NET (International Thermonuclear Experiment Reactor/Next European Torus), STARFIRE (a commercial tokamak ...

Energy Technology Data Exchange (ETDEWEB)

This paper presents a numerical simulation with the EUROPLEXUS fast dynamics software of a pipe whipping phenomenon occurring in the thermal hydraulic conditions of a loss of coolant accident in a PWR primary circuit. Different physical phenomena take place simultaneously during the rupture and the whipping of the pipe such as plasticity, contact, large displacements, two-phase flow regime and fluid structure interaction. Two kinds of numerical models - a simplified pipeline model and a mixed 1D/3D model - are considered and compared throughout modelling and computation. Numerical results are compared with experimental data belonging to the Aquitaine II test campaign.

International Nuclear Information System (INIS)

1 - Description of program or function: T-HEMP3D (Transportable HEMP3D) is a derivative of the STEALTH three-dimensional thermodynamics code developed by Science Applications, Inc. Changes were made primarily in three areas: material specification, coordinate generation, and the addition of sliding surface boundary conditions. STEALTH itself is based entirely on the HEMP3D code written at LLNL. HEMP3D solves problems in solid mechanics involving dynamic plasticity and time-dependent material behavior and problems in gas dynamics. 2 - Method of solution: The equations of motion, conservation equations, and constitutive relations for stresses, strains, hydrostatic pressure, the von Mises yield condition, and artificial viscosity are solved by finite difference methods following the format of the HEMP code (NESC Abstract 775). The physical object is divided into zones defined by 8 grid points. The grid (i,j,k) moves with the material, and the mass within a zone ...

DEFF Research Database (Denmark)

The recently observed X-ray synchrotron emission from four supernova remnants (SNRs) has strengthened the evidence that cosmic-ray electrons are accelerated in SNRs. We show that if this is indeed the case, the local electron spectrum will be strongly time-dependent, at least above roughly 30 GeV. The time dependence stems from the Poisson fluctuations in the number of SNRs within a certain volume and within a certain time interval. As far as cosmic-ray electrons are concerned, the Galaxy looks like actively bubbling Swiss cheese rather than a steady, homogeneously filled system. Our finding has important consequences for studies of the Galactic diffuse gamma-ray emission, for which a strong excess over model predictions above 1 GeV has recently been reported. While these models relied on an electron injection spectrum with index 2.4 (chosen to fit the local electron flux up to 1 TeV), we show that an electron injection ...

International Nuclear Information System (INIS)

Sr3In0.9Co1.1O6, isostructural to Ca3Co2O6, is revealed by the study of the phase relations in the system SrO-InO1.5-CoOx (1000 oC). The structure of Sr3In0.9Co1.1O6 is refined by the combination of powder X-ray and neutron diffraction. Sr3In0.9Co1.1O6 crystallizes in a trigonal lattice with the cell parameters a=b=9.59438(3) A, c=11.02172(4) A with the space group R-3c. Its structure possesses 1D (In/Co)O3 chains running along the c-axis constructed by alternating face-sharing CoO6 octahedra and (In0.9Co0.1)O6 trigonal prisms. The co-occupation of In3+ and Co3+ at the trigonal prismatic site is evidenced by elementary analysis and determined by the structure refinement. Sr3In0.9Co1.1O6 is paramagnetic, and the susceptibility is consistent with the occupation of Co3+ at 10% of the trigonal prismatic positions in a high spin state (HS, S=2). The HS Co3+ is well separated by diamagnetic CoO6 octahedra and InO6 trigonal prisms and shows a g factor ...

International Nuclear Information System (INIS)

The molar extinction coefficients at the absorption maximum of the solvated electron spectrum have been evaluated to be 900, 970, and 1000 mol-1?m2 for 1,2-ethanediol (12ED), 1,2-propanediol (12PD), and 1,3-propanediol (13PD), respectively. These values are two-third or three-fourth of the value usually reported in the published report. Picosecond pulse radiolysis studies have aided in depicting the radiolytic yield of the solvated electron in these solvents as a function of time from picosecond to microsecond. The radiolytic yield in these viscous solvents is found to be strongly different from that of the water solution. The temperature dependent absorption spectra of the solvated electron in 12ED, 12PD, and 13PD have been also investigated. In all the three solvents, the optical spectra shift to the red with increasing temperature. While the shape of the spectra does not change in 13PD, a widening on the blue side of the absorption band is observed in 12ED and 12PD at elevated ...

International Nuclear Information System (INIS)

It is of utmost importance to have a computer code in order to analyze how different parameters (like test duration time) affect the unavailability of safety systems of nuclear. In this context, a study was performed in order to evaluate the model employed by the FRANTIC computer code, which performs detailed calculations on the contribution to the system unavailability originated by hardware failures, component tests and repairs, aiming at considering the influence of different test schemes on the system unavailability. It was shown, by means of the results attained that the numerical model used by the FRANTIC code and the analytical model proposed by APOSTOLAKIS and CHU (4) give unavailability values much similar when the component tests are supposed to be perfect. When a test is supposed to be imperfect (that is, when it may induce a test is supposed to be imperfect (that is, when it may induce a failure on the component being tested), the analytical model presents more conservative ...

Energy Technology Data Exchange (ETDEWEB)

We argue that closed string tachyons drive two spacetime topology changing transitions--loss of genus in a Riemann surface and separation of a Riemann surface into two components. The tachyons of interest are localized versions of Scherk-Schwarz winding string tachyons arising on Riemann surfaces in regions of moduli space where string-scale tubes develop. Spacetime and world-sheet renormalization group analyses provide strong evidence that the decay of these tachyons removes a portion of the spacetime, splitting the tube into two pieces. We address the fate of the gauge fields and charges lost in the process, generalize it to situations with weak flux backgrounds, and use this process to study the type 0 tachyon, providing further evidence that its decay drives the theory sub-critical. Finally, we discuss the time-dependent dynamics of this topology-changing transition and find that it can occur more efficiently than analogous transitions on extended ...

International Nuclear Information System (INIS)

The main goal of this paper is to present a methodology for calculating the radioactivity in the moderator and heat transport systems of Cernavoda NPP Unit 1, with the intention to improve the knowledge on the radionuclides inventories in the operational waste streams, and to aid the licensing process of new near surface repository. In the present paper we describe our methodology for estimating H-3 and C-14 production rates in the heavy-water moderator and heat transport systems using the capacity factors from 1997 to 2007 years. The radioactivity of the difficult-to-measure nuclides is predicted by scaling method using measured concentration in reference CANDU 6 reactor Gentilly-2. The difficult-to-measure radionuclides of primary interest in this study were those with long half-lives which have a significant role for post-closure safety assessment. The equation used to scale fission products (parents and daughters) is based on the equilibrium solution of the ...

Energy Technology Data Exchange (ETDEWEB)

We revisited the quantum Zeno paradox, which claims that a generic quantum system prepared in a state which is not an eigenstate of the Hamiltonian operator and is continuously observed never decays. Since any perfectly isolated quantum system always interact with a vacuum field, we analyze the possibility of using this fact to solve the above mentioned conceptual problem. Therefore we discuss a two-level system or qubit-Bose field interaction Hamiltonians. We consider the quantum dynamics of this two-level system, prepared in the excited state interacting with a Bose field prepared in the Poincare invariant vacuum state. Using a first-order approximation in time-dependent perturbation theory, we evaluate the probability of spontaneous decay of the two-level system driven by the vacuum field. This probability is evaluated for a finite time interval. Using the standard argument to obtain the quantum Zeno paradox, we consider N measurements where N {yields} ...

Energy Technology Data Exchange (ETDEWEB)

Accurately predicting wind turbine blade loads and response is important for the proper design of wind turbines. The need to accurately predict both deterministic and stochastic blade loads is now widely recognized. Previous rotor code development and validation efforts at NREL have concentrated on prediction of deterministic and stochastic blade loads for rigid hub rotors. During the past year this effort was expanded for predicting blade and shaft loads for two-bladed teetering hub rotors. The NREL (formerly SERI) Teetering Rotor Analysis Program (STRAP), a derivative of the Force and Loads Analysis Program (FLAP), can include the effects of rotor undersling, delta-3 and the effects of a concentrated hub mass. The degrees of freedom include rotor teeter and symmetric and asymmetric rotor flap modes. A time-dependent, prescribed yaw motion can also be input to the code. Loads due to turbulent wind inputs are also calculated. In this paper, final code ...

Energy Technology Data Exchange (ETDEWEB)

Ultraviolet (UV) photoirradiation of Ag(I) compounds in the presence of an aqueous Triton X-100 solution has been exploited for the first time to prepare reproducible yellow silver hydrosol. The evolution of nanosized silver particles has been examined critically under the influence of different anions/ligands. Hence, time dependent evolution of silver hydrosol from different silver compounds in micelle via photochemical reduction is observed. Anions/ligands of precursor salts have been found to show profound influence (due to electron scavenging property, solubility, stability etc.) on the evolution route and efficiency of photochemical reduction of Ag(I) to Ag(O) in micelle and thereby classification of silver compounds becomes possible. Kinetic results reveal that the formation of silver particles proceeds via autocatalytic growth mechanism. The observed variation in rate constant values for the evolution of nanoparticles from different ...

Science.gov (United States)

We present computer modeling along with experimental data on the formation of sharp conical tips on silicon-based three-layer structures that consist of a single-crystal Si layer on a 1 {mu}m layer of silica on a bulk Si substrate. The upper Si layers with thicknesses in the range of 0.8-4.1 {mu}m were irradiated by single pulses from a KrF excimer laser focused onto a spot several micrometers in diameter. The computer simulation includes two-dimensional time-dependent heat transfer and phase transformations in Si films that result from the laser irradiation (the Stefan problem). After the laser pulse, the molten material self-cools and resolidifies, forming a sharp conical structure, the height of which can exceed 1 {mu}m depending on the irradiation conditions. We also performed computer simulations for experiments involving single-pulse irradiation of bulk silicon, reported by other groups. We discuss conditions under which different types of structures (cones ...

Energy Technology Data Exchange (ETDEWEB)

We study free and self-interacting scalar quantum field theories in a flat Robertson-Walker metric in the functional Schroedinger picture. We discuss Schroedinger picture quantization, relating it to conventional Heisenberg picture quantization. For the interacting theory, we introduce the time-dependent Gaussian approximation to study time evolution of pure and mixed states and we establish renormalizability of the approximation. We also study the question of computing a finite, renormalized energy-momentum tensor for both the free and the interacting theory in the Gaussian appproximation. Using the adiabatic expansion, we show that the entire subtration necessary to make the the energy-momentum tensor finite in the free theory can be written in terms of covariantly conserved tensors. We further show that the same subtraction is sufficient to make the energy-momentum tensor finite in the Gaussian approximation for the interacting theory provided that the mass and ...

CERN Document Server

We summarize results of recent studies of heavy quarkonia correlators and spectral functions at finite temperatures from lattice QCD and systematic T-matrix studies using QCD motivated finite-temperature potentials. We argue that heavy quarkonia dissociation shall occur in the temperature range $1.2 \\le T_d/T_c \\le 1.5$ by the interplay of both screening and absorption in the strongly correlated plasma medium. We discuss these effects on the quantum mechanical evolution of quarkonia states within a time-dependent harmonic oscillator model with complex oscillator strength and compare the results with data for $R_{\\rm AA}/R_{\\rm AA}^{\\rm CNM}$ from RHIC and SPS experiments. We speculate whether the suppression pattern of the rather precise NA60 data from In-In collisions may be related to the recently discovered X(3872) state. Theoretical support for this hypothesis comes from the cluster expansion of the plasma Hamiltonian for heavy quarkonia in a strongly ...

Energy Technology Data Exchange (ETDEWEB)

The optoelectronic and excitonic properties in a series of linear acenes are investigated using range-separated methods within time-dependent density functional theory (TDDFT). In these highly-conjugated systems, we find that the range-separated formalism provides a substantially improved description of excitation energies compared to conventional hybrid functionals, which surprisingly fail for the various low-lying valence transitions. Moreover, we find that even if the percentage of Hartree-Fock exchange in conventional hybrids is re-optimized to match wavefunction-based CC2 benchmark calculations, they still yield serious errors in excitation energy trends. Based on an analysis of electron-hole transition density matrices, we also show that conventional hybrid functionals overdelocalize excitons and underestimate quasiparticle energy gaps in the acene systems. The results of the present study emphasize the importance of a range-separated and ...

International Nuclear Information System (INIS)

The electromagnetic field due to an air explosion is here studied: neutron and the gamma-rays, generated by neutronic reactions, deposit energy which ionizes atmosphere; recoil electrons are also created by gamma collisions. This data set allows to solve the Maxwell equations which manage the electromagnetic field. The TRIPOLI-2 code studies the coupled neutron-gamma transport in 3D- geometries by the Monte Carlo method. The code has been modified to calculate the photon energy deposited in matter and the recoil electron current created by Compton effect. The method is tested wiht a simple case; then neutron and gamma transport is studied in air kerma, deposited photon energy, electron current are calculated as functions of space and time and the contributions of the different neutronic reactions are separately evaluated. The calculations presented here are only part of studies about this subject. Developments will relate three dimensional calculations and the existence of several ...

Energy Technology Data Exchange (ETDEWEB)

Intramuscular hermorrhage was induced by injecting autologous blood into the paraspinal muscle of 8 rabbits. In order to evaluate the time-dependent changes of hemorrhage observed on MRI, the animals were imaged at different stages of blood resolution at 0.02 tesla (T), and control examined with ultrasound using a 7.5 MHz linear transducer. Six inversion recovery sequences (TR=1 000 ms. TE=30 ms, and TI=18, 48, 148, 201, 302, and 398 ms) were used for the invivo calculation of T1 relaxation times. IR 1 000 (398)/30 imaging was performed before and after the Gd-DOTA administration. The hemorrhage was evident on MR images throughout the study, especially on the T2 weighted (SE 1 000/100) images. MRI showed the healing lesion longer than ultrasound. The T1 relaxation time increased during the time of resolution. Lesions on days 4 to 7 enhanced in intensity after the injection of Gd-DOTA. (orig.).

International Nuclear Information System (INIS)

Complete text of publication follows. The stability regime of the incommensurate phase of quartz is influenced by uniaxial stress. Hence, the phase transition can be induced under isothermal conditions by the application of external mechanical forces. Using real-time neutron scattering the time evolution of structural changes is investigated id detail during stress variations. The time dependent behaviour of the satellite reflection is compared with that one of the fundamental Bragg reflection which - via primary extinction - gives information about the perfection of the crystal. On increasing stress the perfection of the lattice is destroyed immediately while the modulated structure is built up with a delay of about 1 s. Decreasing the stress leads to a reverse behaviour. Moreover, there is evidence that under periodical load residual non-relaxed strain fields survive leading to a different temperature dependence as compared to static ...

International Nuclear Information System (INIS)

The perturbations of the L.R.S. class A spatially homogeneous spacetimes are treated using Hamiltonian methods in conjunction with techniques from the theory of Lie group harmonic analysis. These latter techniques lead to a simple way of handling any set of tensor equations on these background spacetimes which has the same symmetry group as the space-time metric. Once this approach is developed, the Hamiltonian formulation is used to recover in a clean way the Bonanos equations for the perturbations of the perfect fluid models of the class of spacetimes under consideration. The conserved quantities associated with the four-dimensional symmetry group are evaluated and their role in the linearized Hamiltonian dynamics is discussed. The time-dependent linear canonical transformation of the linearized vacuum gravitational phase space adapted to Moncrief's gauge invariant decomposition is described in general for these models and evaluated explicitly for a class of ...

CERN Document Server

We present the results of a search for Extreme Ultraviolet emission in A4059, a cluster with an X-ray emitting cluster gas. Our analysis of Extreme Ultraviolet Explorer (EUVE) Deep Survey observations of this cluster shows that it is associated with diffuse EUV emission. Outside the central 2 arcmin radius the entire EUV emission detected is explained by the low energy tail of the X-ray emitting gas. Within the central 2 arcmin region of the cluster we find a deficit of EUV emission compared to that expected from the X-ray gas. This flux deficit is discussed in the context of the cluster's cooling flow. The results derived for A4059 are compared to EUVE results obtained for other clusters such as Coma, Virgo, A1795, and A2199. As part of the study we have carried out a detailed investigation of the stability of the EUVE Deep Survey detector background. Based on long integrations of blank sky over 27 months we disprove claims of substantial time ...

Energy Technology Data Exchange (ETDEWEB)

The leakage current behaviors of PLZT capacitors with top electrodes of Pt, Ir, and IrO{sub 2} are investigated before and after hydrogen forming gas anneal. The P-E hysteresis and fatigue properties of Pt/PLZT/Pt capacitors are almost recovered after recovery anneal in O{sub 2} ambient. The leakage current mechanisms of PLZT capacitors with Pt and IrO{sub 2} top electrodes are consistent with space-charge influenced injection model showing the strong time dependence irrespective of annealing conditions. On the other hand, the leakage current behavior of Ir/PLZT/Pt capacitor shows steady state independent of time because IrPb, conducting phase, formed at interface between Ir top and PLZT is a high conduction path. Teh leakage current mechanism of Ir/PLZT/Pt capacitor is consistent with Schottky barrier model. (author). 15 refs., 6 figs.

CERN Document Server

We develop and demonstrate the methodology of testing multi-dimensional supernova models against observations by studying the properties of one example of the detonation from failed deflagration (DFD) explosion model of thermonuclear supernovae. Using time-dependent multi-dimensional radiative transfer calculations, we generate the synthetic broadband optical light curves, near-infrared light curves, color evolution curves, full spectral time-series, and spectropolarization of the model, as seen from various viewing angles. All model observables are critically evaluated against examples of well-observed, standard Type Ia supernovae (SNe Ia). We explore the consequences of the intrinsic model asphericity by studying the dependence of the model emission on viewing angle, and by quantifying the resulting dispersion in (and internal correlations between) various model observables. These statistical properties of the model are also evaluated against those of the ...

Energy Technology Data Exchange (ETDEWEB)

The fundamental mechanisms underlying the chemical degradation of polymers can change as a function of environmental stress level. When this occurs, it greatly complicates any attempt to use accelerated tests for predicting long-term material degradation behaviors. Understanding how degradation mechanisms can change at different stress levels facilitates both the design and the interpretation of aging tests. Oxidative degradation is a predominant mechanism for many polymers exposed to a variety of different environments in the presence of air, and there are two mechanistic considerations which are widely applicable to material oxidation. One involves a physical process, oxygen diffusion, as a rate-limiting step. This mechanism can predominate at high stress levels. The second is a chemical process, the time-dependent decomposition of peroxide species. This leads to chain branching and can become a rate-controlling factor at lower stress levels involving time-scales ...

Energy Technology Data Exchange (ETDEWEB)

Air flow and the buoyancy-driven flow through a building`s horizontal openings was discussed. Horizontal openings occur in staircases, stairwells, ventilation shafts and chimneys. Mass and energy transfer through them have important implications regarding energy saving, thermal comfort, control of contaminants and micro-organisms and spread of fire and smoke. The analysis of the buoyancy-driven flow was attained using computational fluid dynamics (CFD). Use was made of the CFD code FLUENT which integrated the Navier-Stokes equations by a time-dependent, finite volume method. Good agreement was achieved between predicted and experimental measurements of flow rate. Results showed that flow patterns in horizontal openings were transient and unstable. The air exchange through the openings occurred in intermittent pulses. The flow rate through the opening increased with the temperature difference between zones in buildings and the size of the horizontal opening. 3 ...

Energy Technology Data Exchange (ETDEWEB)

The United States and Russia have agreed to jointly develop a solar dynamic (SD) system for flight demonstration on the Russian Mir space station starting in late 1997. Two important components of this SD system are the solar concentrator and heat receiver provided by Russia and the US, respectively. This paper describes optical analysis of the concentrator and solar flux predictions on target receiver surfaces. The optical analysis is performed using the code CIRCE2. These analyses account for finite sun size with limb darkening, concentrator surface slope and position errors, concentrator petal thermal deformation, gaps between petals, and the shading effect of the receiver support struts. The receiver spatial flux distributions are then combined with concentrator shadowing predictions. Geometric shadowing patterns are traced from the concentrator to the target receiver surfaces. These patterns vary with time depending on the chosen Mir ...

International Nuclear Information System (INIS)

Uranium Hexafluoride is a material used in the various processes which comprise the front end of the nuclear fuel cycle (conversion, enrichment and fuel fabrication). Confinement of UF6 is a very important safety requirement since this material is highly reactive and presents safety hazards to humans. The present paper discusses the safety relevant aspects of accidental releases of UF6 inside process confinement buildings. Postulated accidental scenarios are analyzed and their consequences evaluated. Implant releases rates are estimated using computer code predictions. A time dependent homogeneous compartment model is used to predict concentrations of UF6, hydrogen fluoride and uranyl fluoride inside a confinement building, as well as to evaluate source terms released to the atmosphere. These source terms can be used as input to atmospheric dispersion models to evaluate consequences to the environment. The results can also be used to define ...

International Nuclear Information System (INIS)

As the first step for development of the corrosion resistant superheater tube materials of 500 C, 100 ata used in high efficient waste-to-energy plants, field corrosion tests of six conventional alloys were carried out at metal temperatures of 450 C and 550 C for 700 and 3,000 hours in four typical Japanese waste incineration plants. The test results indicate that austenitic alloys containing approximately 80 wt% [Cr+Ni] show excellent corrosion resistance. When the corrosive environment is severe, intergranular corrosion of 40#approx#200 microm depth occurs in stainless steel and high alloyed materials. It is confirmed quantitatively that corrosion behavior is influenced by environmental corrosion factors such as Cl concentration and thickness of deposits on tube surface, metal temperature, and flue gas temperature. The excellent corrosion resistance of high [Cr+Ni+Mo] alloys such as Alloy 625 is explained by the stability of its protective oxide, such that the ...

CERN Document Server

We show that accretion disks, both in the subcritical and supercritical accretion rate regime, may exhibit significant amplitude luminosity oscillations. The luminosity time behavior has been obtained by performing a set of time-dependent 2D SPH simulations of accretion disks with different values of alpha and accretion rate. In this study, to avoid any influence of the initial disk configuration, we produced the disks injecting matter from an outer edge far from the central object. The period of oscillations is 2 - 50 s respectively for the two cases, and the variation amplitude of the disc luminosity is 10^38 - 10^39 erg/s. An explanation of this luminosity behavior is proposed in terms of limit cycle instability: the disk oscillates between a radiation pressure dominated configuration (with a high luminosity value) and a gas pressure dominated one (with a low luminosity value). The origin of this instability is the difference between the heat produced by ...

Energy Technology Data Exchange (ETDEWEB)

The atmosphere and the biosphere are inherently coupled to one another. Atmospheric surface state variables such as temperature, winds, water vapor, precipitation, and radiation control biophysical, biogeochemical, and ecological processes at the surface and subsurface. At the same time, surface fluxes of momentum, moisture, heat, and trace gases act as time-dependent boundary conditions providing feedback on atmospheric processes. To understand such phenomena, a coupled set of interactive models is required. Costs are still prohibitive for computing surface/subsurface fluxes directly for medium-resolution atmospheric general circulation models (AGCMs), but a technique has been developed for testing large-scale homogeneity and accessing surface parameterizations and models to reduce this computational cost and maintain accuracy. This modeling system potentially bridges the observed spatial and temporal ranges yet allows the incorporation of necessary details about ...

British Library Electronic Table of Contents (United Kingdom)

Two ent-rosane- (cuzcol, 1 and 6-dehydroxycuzcol, 2) and a abietatriene- (salvadoriol, 3) type diterpenoids have been isolated from Maytenus cuzcoina and Crossopetalum uragoga, respectively, along with five known diterpene compounds (4-8). Their stereostructures have been elucidated on the basis of spectroscopic analysis, including 1D and 2D NMR techniques, and computational data. The absolute configuration of cuzcol was determined by application of Riguera ester procedure. This is the first instance of isolation of ent-rosane diterpenoids from species of the Celastraceae. The isolated diterpenes were found to be potent anti-tumour-promoter agents, and carnosol (7) also showed a remarkable chemopreventive effect in an in vivo two-stage carcinogenesis model.

International Nuclear Information System (INIS)

Supernova explosions within wind-driven bubbles are studied with 2D hydrodynamical calculations. Two different density distributions for the ejecta are considered: (i) a smooth, unfragmented power-law stratification, and (ii) a fragmented distribution. As in 1D models, the presence of the shell of interstellar swept-up matter causes the rapid evolution of the remnant to the radiative phase. The main 2D effects, for both fragmented and unfragmented ejecta, include: (i) substantial chaotic deviations from a purely radial flow in the remnant interior, (ii) efficient turbulent mixing between the ejecta and the shocked wind, resulting in homogenization of the former wind cavity, and (iii) severe distortion of the wind-driven shell by cooling and Rayleigh-Taylor instabilities. (author).

CERN Document Server

We propose an extension of the su(2,2|4) superalgebra to incorporate the F1/D1 string charges in type IIB string theory on the AdS_5 X S^5 background, or the electro-magnetic charges in the dual super Yang-Mills theory. With the charges introduced, the superalgebra inevitably undergoes a noncentral extension, as noted recently in [1]. After developing a group theoretical method of obtaining the noncentral extension, we show that the charges form a certain nonunitary representation of the original unextended superalgebra, subject to some constraints. We solve the constraints completely and show that, apart from the su(2,2|4) generators, there exist 899 complex brane charges in the extended algebra. Explicitly we present all the super-commutators among them.

International Nuclear Information System (INIS)

An overview of LOCA analysis in Japanese industry is presented. The BASH-M code, developed for large scale LOCA reflooding analysis, is given as an example of verification and improvement of US computer programs are given. The code's application to the operational safety analysis concerns the following main areas: 1D drift flux model base computer program CANAC; CANAC-based advanced training simulator; emergency operating procedures. The author considers also the code application to the following new PWR safety design concepts: use of steam generators for decay heat removal at LOCA conditions; use of horizontal type steam generator for maintaining two-phase natural circulation under the reactor coolant system submerged. 9 figs.

CERN Document Server

We study dipolar bosons in a 1D optical lattice and identify a region in parameter space---strong coupling but relatively weak on-site repulsion---hosting a series of stable CDW states whose low-energy excitations, built from "fractional domain walls", are remarkably similar to those of non-abelian fractional quantum Hall states. Here, a conventional domain wall between translated CDW's may split by inserting strings of degenerate, but inequivalent, CDW states. Outside these insulating regions, we find numerous supersolids as well as a superfluid regime. The mentioned phases should be accessible experimentally, and in particular, the fractional domain walls can be created in the ground state using single-site addressing, i.e. by locally changing the chemical potential.

British Library Electronic Table of Contents (United Kingdom)

The endophytic fungus Trichothecium roseum LZ93 from Maytenus hookeri was found to antagonize other pathogenic fungi in vitro. To identify which compound contributed substantially to the antagonism, we fermented the strain and purified its fermentation products. Eleven compounds were obtained, including two trichothecenes, five rosenonolactones, two cardiotonic cyclodepsipeptides, and two sterols. Compound 11?-hydroxyrosenonolactone (1) was assigned according to 1D and 2D-NMR data for the first time. At the same time, the 1H and 13C-NMR assignments for 6?-hydroxyrosenonolactone (2) were revised. Of all of them, only trichothecin (6) showed strong antifungal activity. Based on our observations of the antagonistic activity and the other experimental results, we suggest that the antifungal co...

Energy Technology Data Exchange (ETDEWEB)

In the previous paper, we have derived a dispersion relation for the free electron laser (FEL) gain in the exponential regime taking account the diffraction and electron`s betatron oscillation. Here, we compare the growth rates obtained by solving the dispersion relation with those obtained by simulation calculation for the waterbag and the Gaussian models for the electron`s transverse phase space distribution. The agreement is found to be good except for the limiting case where the Rayleigh length is much longer than the gain length (1-D limit). We also generalize the analysis to the case where the electron beam cross section is elliptical as is usually the case in storage rings, and derive the first-order dispersion relation.

Energy Technology Data Exchange (ETDEWEB)

Heavy-ion reaction with unstable nuclei, {sup 13}N and {sup 11}Be, {sup 13}N+{sup 12}C and {sup 11}Be+{sup 12}C-{sup 10}Be+{sup 13}C were analyzed by a coupled-reaction-channel (CRC) method and formation of valence nucleon molecular orbital was studied by numerical analysing calculation. In this report, 1P1/2 (the ground state of {sup 13}N and {sup 13}C), 2s1/2 (the ground state of {sup 11}Be), 1d5/2 and 1d3/2 orbital were studied as one particle state of valance nucleon in {sup 13}N, {sup 13}C and {sup 11}Be. Moreover, d3/2 state, comparatively higher excited state, was contained into CRC calculation. The effect of this state on CRC scheme was proved very large. We developed new program code to obtain the numerical stable solution. It is necessary to about 200 MB (CRC equation) for {sup 11}Be+{sup 12}C{yields}{sup 10}Be+{sup 13}C and about 300 MB for discussion about molecular orbital. We show that the ...

Energy Technology Data Exchange (ETDEWEB)

Flowsheets for the dissolution of aluminum-clad spent nuclear fuel have been proposed using 0.002 M mercuric nitrate catalyst in 5 to 6 M nitric acid. Previous calculations for flammable gas control during the dissolution of spent nuclear fuel have been extended to cover a range of dissolver purge rates from 40 to 55 scfm. A range of dissolver solution volumes from 12000 to 15000 liters were considered for the large H-Canyon dissolver (6.4D). Depending on the purge rate, anywhere from four to six bundles of MURR fuel can be initially charged to the dissolver (6.4D). For successive charges where the dissolver solution already contains 0.002 M mercury catalyst and the dissolved aluminum from five bundles of MURR fuel, five to nine bundles of additional fuel can be charged depending on the purge rate and the dissolver solution volume. Similar calculations have been performed for the small H-Canyon dissolver (6.1D) for solution volumes that ranged ...

International Nuclear Information System (INIS)

Full text: In heavy-water-moderated power reactors, tritium is primarily produced by neutron capture in deuterium nuclei in the moderator and coolant. For CANDU 6 reactors, the estimated steady-state values are #approx# 3 TBq#centre dot#kg"-"1 D_2O in the moderator and #approx# 74 GBq#centre dot#kg"-"1 D_2O in the coolant. Tritium removal is one option available to reactor operators for use in their heavy water and tritium management strategies. The WTRF is designed to remove tritium from tritiated heavy water in each of the four CANDU units at the Wolsung Site, to immobilize the tritium and to store it on site. The detritiation process is based on three steps: the first one (front-end) involves the transfer of tritium from heavy water to deuterium gas; the second one (enrichment) concentrates the tritium in a cryogenic distillation system to produce essentially pure D_2 and T_2 streams; and in the ...

British Library Electronic Table of Contents (United Kingdom)

A series of NHC silver(I), mercury(II) and palladium(II) complexes, [(1,3-diethylbimy)6Ag4I3]I (2), [(1-benzyl-3-picolylbimy)Ag2Br2]n (3), [(1-benzyl-3-picolylbimy)HgI(CH2CN)]2 (4), {[(1-picolyl-3-npropylbimy)2Hg][Hg2I6]}n (5) and [(1,3-dipicolylbimy)PdCl]Cl (6), as well as one anionic complex [1,3-diethylbimidazolium]2[HgI4] (1) (bimy=benzimidazol-2-ylidene), have been prepared and characterized. Interestingly, a wind wheel-like Ag4I3 arrangement in 2 is formed, 1D polymeric chain containing 12-membered macrometallocycles and quadrangle Ag2Br2 units in 3 is generated, and the a-carbon atom of deprotonated acetonitrile ([CH2CN]-) in 4 participates in coordination with mercury(II) atom. In the crystal packings of complexes 1-6, 2D supramolecular layers or 3D supramolecular architectures are...

CERN Document Server

Learning to love the errror matrix lecture : Learning to love the errror matrix Introductory remarks. Conditional probability. Statistical and systematic errors. Combining results Binomial, Poisson and 1-D Gaussian 2-D Gaussian and the error matrix. Understanding the covariance. Using the error matrix. Estimating the error matrix. Combining correlated measurements Parameter determination by likelihood Do's and don'ts lecture : Parameter determination by likelihood : Do's and don'ts Introduction to likelihood. Error estimate. Simple examples: (1) Breit Wigner (2) Lifetime Binned and unbinned likelihood Several parameters Extended maximum likelihood. Common misapprehensions: Normalisation delta(lnL) = 1/2 rule and coverage Integrating the likelihood Unbinned L_max as goodness of fit Punzi effect Chi-squared and hypothesis testing lecture : Chi-squared and hypothesis testing Basic idea. Error estimates. Several parameters Correlated errors on y. ...

British Library Electronic Table of Contents (United Kingdom)

Une enfant drepanocytaire homozygote SS de 14 ans (sans deficit en G6PD), non transfusee anterieurement, a une cholecystectomie pour lithiase decouverte a un bilan systematique. L'intervention est encadree de 2 transfusions de concentres erythrocytaires (CGR) phenotypes ABO Rh Kell, compatibilises. Quinze jours apres, elle presente une hemolyse aigue associant fievre, ictere, insuffisance renale tubulaire, hemoglobinurie et anemie profonde (Hb 3,6 g/dL). Les RAI deviennent positives avec, entre autres, un auto anticorps anti D suspecte, le test de Coombs direct est positif de type mixte. L'enfant n'est pas retransfusee, mais recoit 1 mg/kg/j de corticoides IV pendant 10 jours. L'hemoglobine retrouve sa valeur de base (9 g/dL) apres 15 jours. Un antigene RH1(D) partiel de type DAR est ulter...

Energy Technology Data Exchange (ETDEWEB)

Asymmetric plasma divided by the magnetic filter (MF) is numerically simulated by the one-dimensional particle-in-cell code VSIM1D. Depending on the asymmetry, the system behaves static or dynamic. In the static state, the potentials of the main plasma and the sub-plasma are given by the sheath potentials, {phi}{sub M} - 3T{sub Me}/e and {phi}{sub S} - 3T{sub Se}/e, respectively, with e being an electron charge and T{sub Me} and T{sub Se} being electron temperatures (T{sub Me} > T{sub Se}). In the dynamics state, while {phi}{sub M} - 3T{sub Me}/e, {phi}{sub S} oscillates periodically between {phi}{sub S,min} - 3T{sub Se}/e and {phi}{sub S,max} - 3T{sub Me}/e. The ions accelerated by the time varying potential gap get into the sub-plasma and excite the laminar shock waves. This periodic phenomenon can be understood as a limit cycle due to transitions between two bifurcated states of {phi}{sub S,min} and {phi}{sub S,max}. (author)

Energy Technology Data Exchange (ETDEWEB)

During second quarter 1992, tritium, trichloroethylene, tetrachloroethylene, chloroethene, antimony, 1,1-dichloroethylene, lead, nonvolatile beta, radium-228, thorium-228, or total alpha-emitting radium (radium-226 and radium-228) exceeded the US Environmental Protection Agency Primary Drinking Water Standards (PDWS) in groundwater samples from monitoring wells at the Mixed Waste Management Facility (MWMF) and adjacent facilities. Tritium and trichloroethylene were the most widespread constituents; 55 (48%) of the 115 monitored wells contained elevated tritium activities, and 23 (20%) wells exhibited elevated trichloroethylene concentrations. Sixty-three downgradient wells screened in Aquifer Zone IIB2 (Water Table), Aquifer Zone IIB[sub 2] (Barnwell/McBean), and Aquifer Unit IIA (Congaree) contained concentrations of tritium, trichloroethylene, tetrachloroethylene, chloroethene, antimony, 1,1-dichloroethylene, lead, nonvolatile beta, radium-228, thorium-228, or total alpha-emitting ...

International Nuclear Information System (INIS)

Obtained experimental data on integral cross sections (ICS) of inelastic scattering of 50.5 MeV #alpha# particles with the excitation of "6","7Li, "9Be, "1"2","1"3C, "1"4C, "1"4N, "2"0Ne, "2"4Mg, "2"8Si nucleus low-lying energy levels are discussed. Regularities, detected in the behaviour of ICS forward scattering for 20-90 deg angles and backscattering for 90-160 deg angles for the target-nucleus under investigation are considered. Effect of reaction open channel number on #alpha#-particle scattering ICS where n,p,d- and #alpha#-channels were considered as the main channels for all the target-nuclei, is discussed. Dependence of #alpha#-particle scattering ICS on the target-nucleus level excitation energy and dependences of reaction open channel number on the channel spin, calculated for 50.5 MeV #alpha# particles and different target nuclei are shown in the diagrams. It is noted that the observed regularities in the #alpha#-particle inelastic scattering ICS are explained by a ...

Energy Technology Data Exchange (ETDEWEB)

Substantial thermal performance improvement in ice-on-tube cold thermal energy storage systems (TES) is possible by making use of porous copper mesh as a Heat Conducting Enhancement Device (HCED). HCEDs are inexpensive heat transfer augmentation devices that can result in faster rate of ice growth and larger final steady state ice build volume by reducing the controlling thermal conduction resistance of the ice layer. This improves the competitiveness of external ice-on-tube systems as compared to other TES systems, such as dynamic ice harvesters and static internal melt systems. In this study the amount of ice growth enhancement is predicted theoretically, by performing simplified 1-D calculations, and is then validated in the laboratory through carefully controlled experiments. This study shows that ice volume increase between 50 and 90% is possible by using HCEDs of the type tested. (author)

International Nuclear Information System (INIS)

The KLL Auger electron spectrum of "8"8Sr generated in the EC-decay of "8"8Y has been analyzed at the instrumental resolution of 11 eV using a combined electrostatic spectrometer. Energies and relative intensities of the all nine transitions were determined and compared with theoretical predictions. Our value of 12067.3(12) eV measured for the absolute energy of the dominant KL_2L_3("1D_2) transition was found to be higher by 7.4 eV (i.e., more than 3#sigma#) than that one obtained in a measurement with external excitation. The discrepancy indicates substantial influence of the 'atomic structure effect' on absolute transition energies in our experiment. Very good agreement of the measured 0.14(3) and predicted 0.12 values for the KL_1L_2("3P_0/"1P_1) Auger transition intensity ratio clearly proved the predicted strong influence of the relativistic effects on the KL_1L_2("3P_0) transition rate even at Z = 38.

Energy Technology Data Exchange (ETDEWEB)

The main purpose of this study is to develop a thermal hydraulic auditing code for the CANDU reactor, modifying the model of existing PWR auditing tool , i.e. RELAP5/MOD3. This scope of project is a fourth step of the whole project, applying the RELAP5/MOD3/CANDU+ version for the real CANDU plant LOCA Analysis and D2O leakage incident. There are three main models under investigation, i.e. Moody critical flow model, flow regime model of horizontal CANDU bundle, and fuel element heatup model when the stratification occurs, especially when CANDU LOCA is tested. Also, for Wolsung unit 1 D2O leakage incident analysis, the plant behavior is predicted with the newly developed version for the first 1000 seconds after onset of the incident, with the main interest aiming for system pressure, level control system, and thermal hydraulic transient behavior of the secondary system. The model applied for this particular application includes heat transfer ...

International Nuclear Information System (INIS)

A lot of recent experimental results show that cladding failure limits to the RCCA ejection accident will be changed because of the impact of the high irradiation on the fuel rod behavior in the reactor. The maximal assembly discharge burnup in Daya Bay unit 1 and 2 will reach up to 52 GMd/tU with 18 month fuel cycle. It is necessary to perform the specific RCCA ejection accident analysis for the high burnup fuel assembly in order to evaluate the maximal enthalpy in the fuel rods. There is no definite design limit of maximal enthalpy for high burnup assembly during the RCCA ejection accident. One could perform the rod ejection accident analysis for the high burnup assemblies and compare the analytical results with the specific experimental results. The RCCA ejection accident analysis for the high burnup assemblies for Daya Bay NPS has been performed based on the conventional methodology (2D-1D). For each anticipated cycle in Daya Bay unit 1 and ...

Energy Technology Data Exchange (ETDEWEB)

We find instanton/cosmological solutions with biaxial Bianchi-IX symmetry, involving nontrivial spatial dependence of the CP{sup 1}-CP{sup 2}-sigma-models coupled to gravity. Such manifolds arise in N = 1, d 4 supergravity with supermatter actions and hence the solutions can be embedded in supergravity. There is a natural way in which the standard coordinates of these manifolds can be mapped into the four-dimensional physical space. Due to its special symmetry, we start with CP{sup 2} with its corresponding scalar ansatz; this further requires the spacetime to be SU(2) x U(1)-invariant. The problem then reduces to a set of ordinary differential equations whose analytical properties and solutions are discussed. Among the solutions there is a surprising, special family of exact solutions which owe their existence to the nontrivial topology of CP{sup 2} and are in 1-1 correspondence with matter-free Bianchi-IX metrics. These solutions can also be ...

Energy Technology Data Exchange (ETDEWEB)

The major problem of measurement of a power spectral density (PSD) distribution of the surface heights with surface profilometers arises due to the unknown Modulation Transfer Function (MTF) of the instruments. The MTF tends to distort the PSD at higher spatial frequencies. It has been suggested [Proc. SPIE 7077-7, (2007), Opt. Eng. 47 (7), 073602-1-5 (2008)] that the instrumental MTF of a surface profiler can be precisely measured using standard test surfaces based on binary pseudo-random (BPR) patterns. In the cited work, a one dimensional (1D) realization of the suggested method based on use of BPR gratings has been demonstrated. Here, we present recent achievements made in fabricating and using two-dimensional (2D) BPR arrays that allow for a direct 2D calibration of the instrumental MTF. The 2D BPRAs were used as standard test surfaces for 2D MTF calibration of the MicromapTM-570 interferometric microscope with all available objectives. ...

International Nuclear Information System (INIS)

In order to evaluate the integrated performance of RELAP5/MOD3/CANDU"+ for CANDU operational transient analysis, we assesed the code to the D_2O leakage event occurred at Wolsung-I, 600 MW(e) CANDU reactor, on Oct. 20, '94. D_2O leakage event was initiated by stuck opening of liquid relief valve No.4 in primary coolant pressure and level control system. Assessment calculation was performed for the plant transients up to 1000 seconds after the initiating event. Calculation results are compared with those measured in primary heat transport system, pressure and inventory control system and boiler secondary system. Comparison with the plant trip log shows that the RELAP5/CANDU"+ is able to simulate the plant transients properly, from which we can conclude that the RELAP5/CANDU"+ is validated for application to CANDU operational transient analysis. CANDU specific models used in the assessment are fuel bundle heat transfer model, decay heat model and MOV(Motor Operated Valve) model.

British Library Electronic Table of Contents (United Kingdom)

Background The objective of this study was to confirm provisional quantitative trait loci (QTL) for cocaine-induced locomotor activation, on chromosomes 1, 5, 6, 9, 12, 15, 16, 17, and 18, previously identified in the AXB/BXA recombinant inbred (RI) and AcB/BcA recombinant congenic (RC) strains of mice derived from A/J (A) and C57BL/6J (B6) progenitors. This was accomplished through a genetic analysis of cocaine-induced activity in an AxB6 F2 cross and a phenotypic survey across a panel of B6.A chromosome substitution strains (CSS) mice. Mice were tested for cocaine-induced activity, following administration of saline and cocaine (20?mg/kg), utilizing an open-field procedure. Results Among AxB6 F2 mice, differences in cocaine-induced activity were associated with loci on chromosome 1 (D1Mi...

International Nuclear Information System (INIS)

Six uranyl coordination compounds, UO_2(OH)(PYCA) (1), UO_2(PYCA)_2(H_2O).2H_2O (2), UO_2(PIC)_2 (3), UO_2(H_2O)_2(NIC)_2 (4), UO_2(OH)(HINIC)(INIC) (5), and UO_2(PYTAC)_2(H_2O)_2 (6) were grown as single crystals via hydrothermal synthesis (PYCA - pyrazine-2-carboxylate, PIC - picolinate, NIC - nicotinate, INIC - iso-nicotinate, and PYTAC - 2-(pyridin-4-yl)thiazole-5-carboxylate) to study their optical properties. All six compounds have been identified via single crystal X-ray diffraction and fully characterized via powder X-ray diffraction, infrared spectroscopy, UV-Vis spectroscopy, and fluorescence spectroscopy. Three of the complexes, 1, 3, and 6, represent new structures, and their synthesis and structural characterization is detailed within. The structures of 2, 4, and 5 have previously been reported in the literature. Coordination polymer 1 crystallizes in the orthorhombic space group Pca21 (a = 13.5476(5) Angstroms, b = 6.6047(2) Angstroms, c = 8.3458(3) Angstroms), and forms ...

Energy Technology Data Exchange (ETDEWEB)

A decade ago, Lovelock and Whitfield raised the question of how much longer the biosphere can survive on Earth. They pointed out that, despite the current fossil-fuel induced increase in the atmospheric CO[sub 2] concentration, the long-term trend should be in the opposite direction: as increased solar luminosity warms the Earth, silicate rocks should weather more readily, causing atmospheric CO[sub 2] to decrease. In their model, atmospheric CO[sub 2] falls below the critical level for C3 photosynthesis, 150 parts per million (p.p.m.), in only 100 Myr, and this is assumed to mark the demise of the biosphere as a whole. Here, this problem is re-examined using a more elaborate model that includes a more accurate treatment of the greenhouse effect of CO[sub 2] a biologically mediated weathering parameterization, and the realization that C4 photosynthesis can persist to much lower concentrations of atmospheric CO[sub 2] ([lt]10 p.p.m.). It was found that a C4-plant-based biosphere could ...

Energy Technology Data Exchange (ETDEWEB)

Moisture profiles from neutron probe data provide valuable information in site characterization and to supplement ground water monitoring efforts. The neutron probe precision error (reproducibility) is found to be about 0.2 vol% under in situ field conditions where the slope in moisture content with depth is varying slowly. This error is about 2 times larger near moisture spikes (e.g., at the vapor phase notch), due to the sensitivity of the probe response to vertical position errors on the order of 0.5 inches. Calibrations were performed to correct the downhole probe response to the volumetric moisture content determined on core samples. Calibration is sensitive to borehole diameter and casing type, requiring 3 separate calibration relations for the boreholes surveyed here. Power law fits were used for calibration in this study to assure moisture content results greater than zero. Findings in the boreholes reported here confirm the broad features seen previously in moisture profiles ...

International Nuclear Information System (INIS)

In order to prevent corrosion failures of machines and structures, it is desirable to know in advance when the corrosion damage will take place, and appropriate measures are needed to mitigate the damage. The corrosion predictions are needed both at development as well as operational stage of machines and structures. There are several forms of corrosion process through which varying degrees of damage can occur. Under certain conditions these corrosion processes at alone and in other set of conditions, several of these processes may occur simultaneously. For a certain type of machine elements and structures, such as gears, bearing, tubes, pipelines, containers, storage tanks etc., are particularly prone to pitting corrosion which is an insidious form of corrosion. The corrosion predictions are usually based on experimental results obtained from test coupons and/or field experiences of similar machines or parts of a structure. Considerable scatter is observed in corrosion processes. The ...

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The Heavy-Ion Fusion Sciences Virtual National Laboratory is pursuing an approach to target heating experiments in the Warm Dense Matter regime, using spacecharge-dominated ion beams that are simultaneously longitudinally bunched and transversely focused. Longitudinal beam compression by large factors has beendemonstrated in the Neutralized Drift Compression Experiment (NDCX) with controlledramps and forced neutralization. Using an injected 30-mA K+ ion beam with initialkinetic energy 0.3 MeV, axial compression leading to ~;;50-fold current amplification andsimultaneous radial focusing to beam radii of a few mm have led to encouraging energy deposition approaching the intensities required for eV-range target heating experiments. We discuss the status of several improvements to our Neutralized Drift Compression Experiment and associated beam diagnostics that are under development to reach the necessary higher beam intensities, including: (1) greater axial compression via a longer ...

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What will be discussed in this report represents a framework upon which multiphase and other real physical effects can be built. Chemical models of increasing complexity are envisioned and this methodology can provide a tool for evaluating new ideas against known experimental data. The recent work to be reported here addresses the multiphase issue of temperature deviation between phases undergoing chemical and heat transport processes. Modeling of the LLNL ODTX experiment will be performed with FLUENT, a commercially available computational fluid dynamics (CFD) code. FLUENT solves flows in 2D or 3D in Cartesian, cylindrical, or general curvilinear coordinates, with steady-state of fully time-dependent analysis. Multiphase flows in which two or more continuous phases are present can be solved with arbitrary volumetric sources of heat, mass, momentum, and chemical species applied through user-defined FORTRAN subroutines. FLUENT models these of phenomena by solving ...

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In cooperation with NRPB, the specifications of the mainframe COSYMA version 95/1 and the PC COSYMA version 2.0 were prepared and the corresponding modifications implemented. Important improvements are dose-rate dependent models for deterministic health effects, the time dependent efficiency of stable iodine tablets, the extension of data bases for the inclusion of activation products, and supplementary evaluation programs. PC COSYMA has been completed by an economics module, further options in the ingestion pathways, and a graphics package for presenting assessment results. COSYMA has been applied for probabilistic dose assessments within paramter studies and special investigations of EPR concepts. RODOS, the real-time on-line decision support system for nuclear emergency management, has been further developed with the aim of the first pilot version 2.0 for pre-operational application in the second half of 1995. At present, some 20 institutes ...

Science.gov (United States)

Spike-timing-dependent plasticity (STDP), a form of Hebbian plasticity, is inherently stabilizing. Whether and how GABAergic inhibition influences STDP is not well understood. Using a model neuron driven by converging inputs modifiable by STDP, we determined that a sufficient level of inhibition was critical to ensure that temporal coherence (correlation among presynaptic spike times) of synaptic inputs, rather than initial strength or number of inputs within a pathway, controlled postsynaptic spike timing. Inhibition exerted this effect by preferentially reducing synaptic efficacy, the ability of inputs to evoke postsynaptic action potentials, of the less coherent inputs. In visual cortical slices, inhibition potently reduced synaptic efficacy at ages during but not before the critical period of ocular dominance (OD) plasticity. Whole-cell recordings revealed that the amplitude of unitary IPSCs from parvalbumin positive (Pv+) interneurons to pyramidal neurons ...

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Insulin receptors on the surface of isolated rat adipocytes were photoaffinity labeled at 12 degrees C with the iodinated photoreactive insulin analogue, 125I-B2 (2-nitro-4-azidophenylacetyl)-des-PheB1-insulin, and the pathways in the intracellular processing of the labeled receptors were studied at 37 degrees C. During 37 degrees C incubations, the labeled 440-kDa insulin receptors were continuously internalized (as assessed by trypsin inaccessibility) and degraded such that up to 50% of the initially labeled receptors were lost by 120 min. Metabolic poisons (0.125-0.75 mM 2,4-dinitrophenol (DNP) and 1-10 mM NaF), which led to dose-dependent depletion of adipocyte ATP pools, inhibited receptor loss, and caused up to 3-fold increase in intracellular receptor accumulation. This effect was due to inhibition of intracellular receptor degradation, and there was no apparent effect of the metabolic poisons on initial internalization of the receptors. Following maximal intracellular ...

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This thesis is concerned with the crystallisation behaviour of polymers near to a free surface or a buried interface. The properties of polymers are expected to differ significantly near to an interface (either with air or another polymer), due to the contributions of (a) chain configurations induced at the interface, and (b) different mobilities between interfacial regions and the bulk of the sample. For a semi-crystalline polymer, properties such as the degree of crystallinity and the crystallisation kinetics may be enhanced near to a free surface. Grazing incidence x--ray diffraction (GIXD) is used to investigate such effects in poly(ethylene terphthalate) (PET), showing that a lower crystallisation temperature is obtained at the surface, and the crystallisation kinetics are faster at the surface for all temperatures. It is proposed that in thin films of PET, this surface-induced ordering provides nucleation sites for crystallisation in the bulk. GIXD is also used to investigate the ...

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In this paper, the turbulence structures of premixed impinging jets are investigated by three different experimental techniques: time-resolved particle image velocimetry (TPIV) visualisation, hot wire anemometry (HWA) and acoustic signal processing. The focus is on the TPIV, with the other two techniques providing supplementary information. The 2-D velocities of the impinging jets were obtained by TPIV. The contour maps of velocity derivatives were computed to facilitate the visualisation of the turbulence structure of the reactant part of turbulent impinging flames. Particular attention was concentrated on the turbulence structures out of the burner nozzle and their interactions with the combustion process. It was found that the contour plots are effective in visualising time-dependent structures. It is demonstrated that the derivatives of the velocity field are able to reveal many otherwise hidden turbulence patterns. Test cases were designed to facilitate easy ...

International Nuclear Information System (INIS)

The present study was designed to assess the radioprotective effects of amifostine on ovarian follicles. Three week-old female mice with or without pretreatment of amifostine were irradiated with 6.42 Gy of #gamma# -ray. Ovaries were collected 0 and 6h after irradiation. DNA fragmentation pattern and expression of genes and activity of proteins related with apoptosis were investigated by means of RT-PCR and Western blot. Proliferation of granulosa cells was reduced and incidence rate of follicular atresia was increased in ovarian follicles in #gamma# -ray irradiated mice compared to those in control or amifostine-treated group. DNA fragmentation was increased in time-dependent manner in granulosa cells of all irradiated groups. However, no difference between amifostine pre-treated group and irradiated groups was found and the expression of p53 as tumor suppressor gene and Bax as one of pro-apoptotic Bcl-2 family was increased in irradiated mice ovaries. PARP as DNA ...

Energy Technology Data Exchange (ETDEWEB)

The temporal evolution of linear toroidal ion temperature gradient (ITG) modes is studied based on a kinetic integral equation including an initial condition. It is shown how to evaluate the analytic continuation of the integral kernel as a function of a complex-valued frequency, which is useful for analytical and numerical calculations of the asymptotic damping behavior of the ITG mode. In the presence of the toroidal {nabla}B-curvature drift, the temporal dependence of the density and potential perturbations consists of normal modes and a continuum mode, which correspond to contributions from poles and from an integral along a branch cut, respectively, of the Laplace-transformed potential function of the complex-valued frequency. The normal modes have exponential time dependence with frequencies and growth rates determined by the dispersion relation while the continuum mode, which has a ballooning structure, shows a power law decay ...

International Nuclear Information System (INIS)

To accomplish the environmental radiological surveillance need of India's ambitious nuclear power programme, Health Physics Division is infusing new technologies and improved analytical techniques for day to day measurements of various radionuclides in different environmental matrices. It is essential to have techniques for measuring the concentration of radionuclides just above the background level since the discharges from the nuclear facilities are very low i.e. in the range of 5-10% of the prescribed discharge limits by the regulatory bodies. In view of developing ultra-sensitive techniques, the aim of ongoing programmes of the division is to meet the challenges of measuring ultra trace level of radioactivity by adopting state of art new instrumentation and improved sample processing techniques. This will allow us to measure the lowest level of radioactivity (3H, 90Sr, 137Cs, 239+240Pu, etc.) in the environment and thereby estimating the lowest doses to the members of public. ...

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An analysis was perfonned on the mid-latitude scintillation and coherence frequency bandwidth (Fcoh) using transionospheric VHF signal data. The data include 1062 events spanning from November 1997 to June 2002. Each event records FORTE satellite received VHF signals from LAPP located at Los Alamos, New Mexico. Fcohs were derived to study scintillation characteristics on diurnal and seasonal variations, as well as changes due to solar and geomagnetic activities. Comparisons to the VHFIUHF coherence frequency bandwidth studies previously reported at equatorial and mid-latitude regions are made using a 4th power frequency dependence relationship. Furthennore, a wideband ionospheric scintillation model, WBMOD, was used to estimate Fcohs and compared with our VHF Fcoh values. Our analysis indicates mid-latitude scintillation characteristics that are not previously revealed. At the VHF bottom frequency range (3035 MHz), distinguished smaller Fcohs are found in time period from sunset to ...

International Nuclear Information System (INIS)

A modified accumulator was devised to measure surface radon flux from porous media. It consists of a collector hood accumulator with a homogenizer pump and a pressure balancer. The latter was used to compensate for any pressure changes produced during sample withdrawl and hence eliminate additional radon transport from media. Errors resulting from radon back diffusion due to decreasing concentration gradient with time across the interface were eliminated by measuring radon concentrations in the accumulator for two different periods of time and calculating the true radon flux, J(o), from the solution of a time-dependent radon transport equation. Core samples from the observation site were withdrawn for laboratory determination of pkrosity, moisture content, bulk and grain densities, Ra-226 source concentration and the fraction of Rn-222 produced in the void volume. The data were used to calculate the radon diffusion coefficient for the media. Using the present ...

International Nuclear Information System (INIS)

The High Flux Isotope Reactor (HFIR) located at Oak Ridge National Laboratory is one of the world's most powerful research reactors. In 1996, one year after the demise of the Advanced Neutron Source Project, the U.S. Department of Energy embarked on an aggressive program to upgrade the neutron scattering facilities at the HFIR. These upgrades, which are now in progress, include the installation of larger beam tubes, a high-performance hydrogen cold source, and additional neutron guides and neutron scattering instruments. An extensive analysis effort was performed over the past 4 yr to support the design of the modified beamlines and new user facilities and to assess the impact of the upgrades on the integrity of the existing reactor system. The results of three of these analyses are summarized here. Specifically, results are presented for analyses related to the design of the new cold neutron source (CNS), the assessment of beam tube changes on the anticipated pressure vessel lifetime, ...

International Nuclear Information System (INIS)

Analyzing various SBLOCA with high pressure safety injection (HPSI) at VVER-440/213, we met a surprising phenomenon - a 'natural' circulation post SG heat transfer reversal. This is not usual, because normal natural circulation (NC) in primary circuit is connected with positive heat transfer at SG. If there is reverse heat transfer at SG (as soon as the break enthalpy outflow is sufficient for removal of reactor decay heat), it should obstruct any natural circulation. The question was, what is the driving force of this 'non-standard natural circulation'. After all we revealed that force - it is the density difference between the colder water in reactor downcomer (cold water from HPSI) and warmer water in inner reactor (lower plenum, core, upper plenum). This phenomenon could be confusing for operating personal, because there would be an opposite temperature difference at the loop than by normal natural circulation (under non-standard NC conditions water is heated in SG so there is ...

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Classical semiconductor physics has been continuously improving electronic components such as diodes, light-emitting diodes, solar cells and transistors based on highly purified inorganic crystals over the past decades. Organic semiconductors, notably polymeric, are a comparatively young field of research, the first light-emitting diode based on conjugated polymers having been demonstrated in 1990. Polymeric semiconductors are of tremendous interest for high-volume, low-cost manufacturing (''printed electronics''). Due to their rather simple device structure mostly comprising only one or two functional layers, polymeric diodes are much more difficult to optimize compared to small-molecular organic devices. Usually, functions such as charge injection and transport are handled by the same material which thus needs to be highly optimized. The present work contributes to expanding the knowledge on the physical mechanisms determining device performance by ...

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The radionuclide characteristics of light-water-reactor (LWR) spent fuel play key roles in the design and licensing activities for radioactive waste transportation systems, interim storage facilities, and the final repository site. Several areas of analysis require detailed information concerning the time-dependent behavior of radioactive nuclides including (1) neutron/gamma-ray sources for shielding studies, (2) fissile/absorber concentrations for criticality safety determinations, (3) residual decay heat predictions for thermal considerations, and (4) curie and/or radiological toxicity levels for materials assumed to be released into the ground/environment after long periods of time. The crucial nature of the radionuclide predictions over both short and long periods of time has resulted in an increased emphasis on thorough validation for radionuclide generation/depletion codes. Current radionuclide generation/depletion codes have the capability to follow the ...

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X-ray ablation of material from the first wall and other components of an ICF (Inertial Confinement Fusion) chamber is a major threat to the laser final optics. Material condensing on these optics after a shot may cause damage with subsequent laser shots. To ensure the successful operation of the ICF facility, removal rates must be predicted accurately. The goal for this dissertation is to develop an experimentally validated x-ray response model, with particular application to the National Ignition Facility (NIF). Accurate knowledge of the x-ray and debris emissions from ICF targets is a critical first step in the process of predicting the performance of the target chamber system. A number of 1-D numerical simulations of NIF targets have been run to characterize target output in terms of energy, angular distribution, spectrum, and pulse shape. Scaling of output characteristics with variations of both target yield and hohlraum wall thickness are ...

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Computational transport models are described with applications in three problem areas related to unsaturated zone moisture movement beneath Area G. These studies may be used to support the ongoing maintenance of the site Performance Assessment. The three areas include: a 1-D transient analysis with average tuff hydraulic properties in the near surface region with computed results compared to field data; the influence on near surface transient moisture percolation due to realistic distributions in hydraulic properties derived statistically from the observed variance in the field data; and the west to east moisture flow in a 2-D steady geometry approximation of the Pajarito Plateau. Results indicate that a simple transient model for transport of moisture volume fraction fits field data well compared to a moisture pulse observed in the active disposal unit, pit 37. Using realistic infiltration boundary conditions for summer showers and for spring ...

Science.gov (United States)

Acetylcholine-rich synaptic vesicles were isolated from myenteric plexus-longitudinal muscle strips derived from the guinea pig ileum by the method of Dowe, Kilbinger, and Whittaker [J. Neurochem. 35, 993-1003 (1980)] using either unstimulated preparations or preparations field-stimulated at 1 Hz for 10 min using pulses of 1 ms duration and 10 V . cm-1 intensity. The organ bath contained either tetradeuterated (d4) choline (50 microM) or [3H]acetate (2 muCi . ml-1); d4 acetylcholine was measured by gas chromatography-mass spectrometry. As with Torpedo electromotor cholinergic vesicle preparations made under similar conditions the distribution of newly synthesized (d4 or [3H]) acetylcholine in the zonal gradient from stimulated preparations was not identical with that of endogenous (d0, [1H]) acetylcholine, but corresponded to a subpopulation of denser vesicles (equivalent to the VP2 fraction from Torpedo) that had preferentially taken up newly ...

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By contrast to the large mass, complexity and recirculating power of conventional drivers for inertial confinement fusion (ICF), antiproton annihilation offers a specific energy of 90MJ/{micro}g and thus a unique form of energy packaging and delivery. In principle, antiproton drivers could provide a profound reduction in system mass for advanced space propulsion by ICF. We examine the physics underlying the use of antiprotons ({bar p}) to drive various classes of high-yield ICF targets by the methods of volumetric ignition, hotspot ignition and fast ignition. The useable fraction of annihilation deposition energy is determined for both {bar p}-driven ablative compression and {bar p}-driven fast ignition, in association with 0-D and 1-D target burn models. Thereby, we deduce scaling laws for the number of injected antiprotons required per capsule, together with timing and focal spot requirements. The kinetic energy of the injected antiproton ...

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Lithium-ion batteries are becoming more and more important not only for portable electronic devices, but also in prevision of high power electric vehicles. In such an optic, deep studies regarding all the components of a secondary battery are in development. In this study, high voltage cathode materials have been selected. Crystals with spinel structure have a 3D vacancy pathway suitable for Li-ions transport. The material under study was LiNi{sub 0.5}Mn{sub 1.5}O{sub 4} doped with magnesium replacing the nickel. Various samples were synthesized via three different routes: a solid-state method, a modified sol-gel method and a xerogel method. The structure and morphology of the powders were analyzed with HRTEM and XRD. Electrochemical tests were also performed. A wide range of particle sizes (from micro to nanosize) was the result of the different synthesis routes. Unfortunately pure materials were not always obtained. The electrochemical tests showed improvement of the ...

Science.gov (United States)

We use a massively parallel 3D hybrid particle code, dHybrid, to simulate the deflection of plasma beams by a dipole like magnetic field in a laboratory environment. Dipole magnetic fields, along with a plasma injection source to inflate the magnetic field, are now being studied as means of deflecting solar wind and Energetic Particles away from spacecrafts [1,2,3]. We have considered three setups, consistent with the experiments, with a plasma beam fired at i) a dipole field with no plasma injection, ii) a plasma injection source with no dipole field and iii) a dipole field with a plasma injection source. The hybrid simulations help understand the relevant physical phenomena, and enable extrapolation to space plasma scenarios, where setups are similar but plasma parameters differ significantly. The simulation results consistently show the plasma beam being deflected by the dipole field, in the first scenario, with the deflecting distance determined by the magnetic field intensities. ...

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Mono-dispersed cubic CeO{sub 2} nanoparticles have been synthesized using a surfactant-assisted method with laurylamine hydrochloride and cerium alkoxide modified with acetylacetone in an aqueous solution system. The prepared cubic CeO{sub 2} nanoparticles had a highly crystallized structure at 353 K and formed rod-like structures by calcination at 673 K after freeze-drying the CeO{sub 2} gel. We discovered a clear potential to make 1D, 2D or 3D CeO{sub 2}-materials with a well-controlled characteristic length and shape by assembling cubic-shaped CeO{sub 2} nanoparticle building blocks. CeO{sub 2}-TiO{sub 2} composite nanostructures have also been synthesized by changing the mole ratio of cerium alkoxide/titanium alkoxides. By utilizing the redox characteristic of CeO{sub 2}, CeO{sub 2} nanoparticles and CeO{sub 2}-TiO{sub 2} composite nanostructures after calcination, showed reaction activity toward the oxidization of I{sup -} to I{sub 2}, due ...

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Protocol changes and options contained within US Environmental Protection Agency whole effluent toxicity tests represent variables that have the potential to affect bioassay performance and interpretation of results. Variables evaluated in this study include: the change in allowable age in the Pimephales promelas acute bioassay from up to 90 d to a maximum of 14 d, age-specific acute responses of P. promelas among the allowable ages of 1 to 14 d, change in the chronic growth endpoint definition from final mass to biomass, differences between hemacytometer and fluorometer measurements in the Selenastrum capricornutum protocol, and options for statistical interpretation of species sensitivity in multiple test/species screening bioassays. Clear age-related sensitivity and precision differences were observed in acute responses of P. promelas. Results obtained using the younger age classes were typically more variable in studies of both 1- to 14-d-old and 14- to 90-d-old P. promelas. In the ...

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The crystal structure of borophosphates ABPO{sub 5} (A = alkaline earth or Pb) was resolved on a polycrystalline sample using the Rietveld method. The x-ray diffraction patterns data show that ABPO{sub 5} crystallize in a centrosymmetric space group P3{sub 1}21 and their structure is related to the borogermanates REBGeO{sub 5} with a stillwellite-type structure. Pr{sup 3+} ion was used as a local structural probe to corroborate the structural resolution results. Absorption and fluorescence spectra of A{sub 1-x}Pr{sub x}BP{sub 1-x}Ge{sub x}O{sub 5} (A alkaline earth or Pb; x = 0.05) have been investigated at different temperatures. At 9 K the 3{sup H}{sub 4}{yields}{sup 3}P{sub 0} transition of trivalent praseodymium ion (4f{sup 2} configuration) is observed as a single line. This indicates a unique crystallographic site for the rare earth ion in these compounds replacing the divalent cation. Energy level schemes were deduced from the low-temperature spectroscopic measurements. ...

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The experimental effect investigation programme on Zircaloy-4/air oxidation was pursued and expanded to isothermal specimen exposure and the comparison of the oxidation between the atmospheres Ar/O{sub 2} and air. In close connection with the EC project OPSA, which is meanwhile terminated, the investigation concerned specimen exposure in a thermobalance to flowing atmospheres, namely dry Ar/O{sub 2} of composition 80/20 or synthetic air, respectively. As test parameters the linear heat-up rate was varied in the range 5 to 40 K/min and the ramp or holding temperature between 800 and 1500 C. Mass increase and reaction rate were continuously recorded or evaluated in temperature/time dependence. The oxide scale growth was found to be accompanied by colour changes, crack formation and spalling of layers, as well as by dimensional substrate growth, which are the reasons for the observed kinetic results. The microstructural investigation confirms ...

International Nuclear Information System (INIS)

Three blocks of non-welded tuff, one nominally one cubic foot (trial block) in volume and the other two, nominally one cubic meter (1 m3) in volume, were excavated from the Busted Butte Test Facility on the Nevada Test Site in 1999 and transported to the Atomic Energy of Canada Limited Whiteshell Laboratories in Pinawa, Manitoba. The trial block and one of the 1-m3 blocks were used for radionuclide migration experiments under unsaturated conditions; the remaining 1-m3 block was used for similar migration experiments under saturated conditions. After a vertical flow of synthetic transport solution was set up under unsaturated conditions, a suite of conservative and chemically reactive radionuclide tracers was injected at volumetric flow rates of 20 mL/hr in the trial block, and 10 mL/hr in two locations on the upper surface of the 1-m3 block. These flow rates correspond to infiltration rates of about 120 cm/year and about 17 cm/year, respectively. The duration of the migration ...

Energy Technology Data Exchange (ETDEWEB)

One- and two-dimensional NMR techniques have been used to investigate the solution structures of (2S,6S,11S,15S)-2,6,11,15-tetramethyl-1,4,7,10,13,16-hexaoxacyclooctadecane (I) and (2R,3R,11R,12R)-2,3,11,12-tetramethyl-1,4,7,10,13,16-hexaoxyacyclooctadecane (II) macrocycle complexes of CaCl{sub 2} and Ca(NO{sub 3}){sub 2} in CDCl{sub 3}. Previous chiroptical studies of these and similar crown complexes by circularly polarized luminescence (CPL), total luminescence (TL), and circular dichroism (CD) spectroscopy have shown that the macrocycle asymmetric carbons in these complexes constrain the ring such that the sense of the ring twist in the S chiral ring complexes is opposite to that in the R chiral ring complexes. These studies have also shown that there is an added chirality element in the di- and trivalent (alkaline earth and lanthanide metal, respectively) nitrate complexes of I and II associated with the twist of the nitrate anions relative to one another as they sterically ...

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The optical absorption of the Tm{sup 3+} ion in the gadolinium oxychloride (GdOCl) matrix in the UV, visible, and NIR range was studied at temperatures between 9 and 300 K. The visible luminescence of GdOCl:Tm{sup 3+} under Ar{sup +} ion laser and mercury lamp excitation was recorded at 9, 77, and 300 K, too. The crystal field (CF) splitting of the {sup 3}H{sub 4-6}, {sup 3}F{sub 2-4}, {sup 1}G{sub 4}, {sup 1}D{sub 2}, and {sup 1}I{sub 6} levels of the Tm{sup 3+} ion deduced from the spectra was analysed according to the C{sub 4v} point symmetry of the RE{sup 3+} site. The resulting energy level scheme, consisting of 39 levels (i.e. 55 Stark components) out of the total of 70 (91) for the whole 4f{sup 12} configuration, was simulated with the aid of a phenomenological theory taking simultaneously into account both the free-ion and CF effects. The model included 13 adjustable parameters describing the electrostatic (the Racah parameters E{sub ...

Energy Technology Data Exchange (ETDEWEB)

Full text of publication follows: Different to the very simple class of homogeneous non-equilibrium models (HEM) an one dimensional thermal-hydraulic theoretical drift-flux based and thus non-homogeneous coolant channel model and, as a result, an in itself complete thermal-hydraulic coolant channel module CCM have been established allowing to simulate in a very general way the steady state and transient behaviour of the most important parameters of a single- or two-phase fluid flowing within any type of heated or non-heated coolant channel (with an eventually varying cross flow area). To avoid mathematical discontinuities at the transition from single- to two-phase flow the coolant channel will, in its general form, be split into different regions, i.e. be looked as a basic channel (BC) which can consist of a number of different flow regimes and can, accordingly, be subdivided into a number of sub-channels (SC-s). All of them belong, obviously, to only two types of SC-s, a SC with an ...

International Nuclear Information System (INIS)

During the 2007 Niigataken Chuetsu-oki earthquake, strong ground motion with the peak acceleration of 680 cm/s/s which was larger than that of the empirical prediction was recorded at the base mat of the No.1 reactor building of Kashiwazaki-Kariwa Nuclear Power Station (NPS). Furthermore, in the Kashiwazaki-Kariwa NPS, over twice difference of 680 vs. 322 cm/s/s of peak acceleration between the No.1 and the No.6 reactor buildings was observed on the base mat. From the results of recent research, it is suggested that the deep sedimentary layers can be one of the important factors to elucidate these phenomena. In this study, at first, the applicability of microtremor array measurements for estimation of deep S-wave velocity structure (#approx#Vs=3 km/s layer) are discussed. Vertical microtremors were observed in three arrays at the Kashiwazaki-Kariwa NPS with the maximum station spacings of 3.04 km, 1.49 km and 0.75 km, respectively. The Rayleigh wave phase velocity in a frequency range ...

International Nuclear Information System (INIS)

Description or function: WLUP contains validated WIMS-D formatted cross section libraries in 69 and 172 energy group structures for nuclear reactor calculations. Materials from recently released evaluated nuclear data libraries are included. The NJOY nuclear data processing system was applied for generating the cross section files following the models and conventions built into the WIMS-D lattice code. The relevant features for the WIMS users are: - Energy group structures: 69 and 172 energy groups. - List of materials: WIMS ID, general information, source of data. - Cross sections: 69 and 172 group plots. - Resonance data: WIMS ID, temperature, background cross sections. - Goldstein-Cohen factors: Goldstein-Cohen lambda values. - Thermal scattering data: thermal scattering laws and P1 matrixes. - Fission spectrum: fission spectrum data. - Burnup data: burnup chains. - Fission product yields: fission yield tables. - Pseudo lumped fission product: Description of pseudo fission product. ...