A procedure for code Verification by the Method of Manufactured Solutions (MMS) is presented. Although the procedure requires a certain amount of creativity and skill, we show that MMS can be applied to a variety of engineering codes which numerically solve partial differential equations. This is illustrated by detailed examples from computational fluid dynamics. The strength of the MMS procedure is that it can identify any coding mistake that affects the order-of-accuracy of the numerical method. A set of examples which use a blind-test protocol demonstrates the kinds of coding mistakes that can (and cannot) be exposed via the MMS code Verification procedure. The principle advantage of the MMS procedure over traditional methods of code Verification is that code capabilities are tested in full generality. The procedure thus results in a high degree of confidence that all coding ...
The objective of this study is to establish evaluation and verification guideline for the APR 1400 and to investigate the thermal-hydraulic characteristics for fluidic device is analyzed using FLUENT. The scope and major results of research are flow characteristics for fluidic device. In this study, three-dimensional numerical model for fluidic device is developed adequately for, and results are compared with experimental data performed by VAPER (VAlve Performance Evaluation test Rig) in KAERI with an aim to verify numerical simulation. In addition, the parametric study has also carried out to investigate the effect of major parameters such as velocity and pressure inside FD chamber.
In this letter we report a clear and unambiguous observation of the out-of-plane quadrupole magnetic field suggested by numerical simulations in the reconnecting current sheet in the Magnetic Reconnection Experiment (MRX). Measurements show that the Hall effect is large in collisionless regime and becomes small as the collisionality increases, indicating that the Hall effect plays an important role in collisionless reconnection.
BackgroundControversy exists about how to effectively measure patient reported outcomes in IBS clinical trials. Pain numeric rating scales (NRS) are widely used in...Full Text Available
The Kyoto Protocol foresees emission trading but does not yet specify verification of (uncertain) emissions. This paper analyses a setting in which parties can meet their emission targets by reducing emissions, by investing in monitoring (reducing uncertainty of emissions) or by (bilaterally) trading permits. We derive the optimality conditions and carry out various numerical simulations. Our applications suggest that including uncertainty could increase compliance costs for the USA, Japan and the European Union. Central Europe and the Former Soviet Union might be able to gain from trading due to higher permit prices. Emissions trading could also lower aggregate uncertainty on emissions.
The scope of the present article is two-fold. Firstly, to conduct an experiment to provide the temperature-time history of the cooling of a hot ball bearing in quiescent ambient air. Secondly, to predict the temporal variation of the bearing under the hypothesis of natural convection, radiation or natural convection coexists with radiation for a non-vanishing total hemispherical emissivity of the surface of the bearing. Numerical solutions of the three governing nonlinear lumped heat equations were carried out with a Runge-Kutta-Fehlberg (RKF45) algorithm accounting for automatic step size control. The experimental data was obtained with chrome steel ball bearings of diameter 0.953 cm (7/16 in) heated in an electric oven to a pre-set temperature. The heated bearing was exposed later to ambient air at atmospheric temperature and pressure. (orig.)
The abstract is additional with repect to the paper published in JGCD. Ordinary Earth satellites are usually placed into five categories of special orbits: sun-synchronous orbits, orbits at the critical inclination, frozen orbits, repeating ground track orbits, and geostationary orbits. This paper investigates their counterparts around Mars and examines the basic nature of these orbits, which are of special interest for missions conducted around Mars, including Mars reconnaissance. Mars' gravity field is much more complicated, with relatively smaller J2, compared to Earth's, which makes the behaviors of these Martian orbits different from those of Earth. Analytical formulations and numerical simulations are used to analyze these Martian orbits and compare them with their Earth counterparts. First, mean element theory is employed to describe variations of orbital elements and give the constraint conditions for achieving these special orbits. Then, ...
BackgroundChanges in ionic concentration have a fundamental effect on numerous physiological processes. For example, IP3-gated thapsigargin sensitive intracellular calcium...Full Text Available
BackgroundThe epidemiology of avian influenza viruses (AIVs) in gulls is only partially known. The role of the world's most numerous gull species, the black-legged kittiwake (Rissa...Full Text Available
BackgroundSurface electromyography (sEMG) signals have been used in numerous studies for the classification of hand gestures and movements and successfully implemented in the position...Full Text Available
BackgroundNumerous microRNAs (miRNAs) have heterogeneous ends resulting from imprecise cleavages by processing nucleases and from various non-templated nucleotide additions. The...Full Text Available
BackgroundGrapevine is subjected to numerous pests and diseases resulting in the use of phytochemicals in large quantities. The will to decrease the use of phytochemicals leads to...Full Text Available
BackgroundThe epidermal growth factor receptor (Egfr) with its numerous ligands has fundamental roles in development, cell differentiation and physiology. Dysfunction of the receptor-ligand...Full Text Available
BackgroundDespite numerous treatments available for deteriorated cutaneous wound healing such as a diabetic foot, there is still the need for more effective therapy. Adipose-derived...Full Text Available
BackgroundRed ripe tomatoes are the result of numerous physiological changes controlled by hormonal and developmental signals, causing maturation or differentiation of various fruit...Full Text Available
A new three-dimensional treatment planning system (TPS) based on convolution/superposition algorithms (TMS-Radix from HELAX AB, Uppsala, Sweden) was recently installed at the University Hospital in Lund. The purpose of the present study was to design a quality assurance and acceptance testing programme to meet the specific characteristics of this convolution model. The model is based on parametrization of a non-measurable quantity - the polyenergetic pencil beam. However, the verification of the treatment planning model is still dependent on numerous comparisons of measured depth-doses and dose profiles. The test programme was divided in two basic parts: (i) model implementation and beam data consistency and (ii) model performance and limitations in special situations. The first part was scheduled for all photon beam qualities available before they could be used for clinical treatment planning. The second part was performed for selected ...
The Predictive Capability Maturity Model (PCMM) is a new model that can be used to assess the level of maturity of computational modeling and simulation (M&S) efforts. The development of the model is based on both the authors experience and their analysis of similar investigations in the past. The perspective taken in this report is one of judging the usefulness of a predictive capability that relies on the numerical solution to partial differential equations to better inform and improve decision making. The review of past investigations, such as the Software Engineering Institute's Capability Maturity Model Integration and the National Aeronautics and Space Administration and Department of Defense Technology Readiness Levels, indicates that a more restricted, more interpretable method is needed to assess the maturity of an M&S effort. The PCMM addresses six contributing elements to M&S: (1) representation and geometric fidelity, (2) physics ...
Purpose/Objective: At present, treatment verification between portal and reference images is performed based on manually-identified features by radiation oncologist, which is both time-consuming and potentially error-prone. There is a demand for the computerized verification procedure in clinical application. The purpose of this study is to develop a computerized portal verification scheme for pelvic treatment fields. Materials/Methods: The automated verification system involves image acquisition, image feature extraction, feature matching between reference and portal images and quantitative evaluation of patient setup. Electronic portal images with a matrix size of 256 x 256 and 12 bit gray levels were acquired using a liquid matrix electronic portal imaging device. Simulation images were acquired by digitizing simulation films using a TV camera into images with 256 x 256 matrix and 8 bit gray levels. ...
In order to develop a numerical tool for the fast evaluation of CANDU refuelling schemes, a Linear Sensitivity Matrix method (LSM) is developed. It assumes that all the effects caused by various perturbations to the core state are independent to each other and the core response to a perturbation is proportional to its magnitude. In this way, the main core parameters of a refuelling scheme can be derived by simple algebraic operations with the use of pre-calculated sensitivity matrices, without resorting to the complicated and time-consuming 3D core calculation. Verification against the Qinshan CANDU reactor operation history demonstrates that LSM is capable of generating accurate results and running very fast for evaluating a refuelling scheme. (authors)
This is a numericalverification of two groups of pipe whip tests sponsored or cosponsored by EPRI. Experimental data of the two pipe whip tests, one by Tennessee Valley Authority (TVA) and by FRAMATOME/CEA, were provided by EPRI. A nonlinear finite element code, ABAQUS-EPGEN, developed under partial sponsorship by EPRI was used for modeling the pipe whip tests. Beam elements together with an equivalent nonlinear spring element or a partial shell mesh were used to model pipes and elbow in the pipe whip tests. Material nonlinearity due to plasticity, strain rate effects, and temperature, as well as geometric nonlinearity due to large rotation and boundary conditions were included in the study. Effects of strain rate and modeling techniques were assessed. Results by current industry approach were also included as a reference solution. This report can be used as a guideline for numerical simulation of pipe whip phenomena. 74 ...
In the last two decades the performance of numerical wind-wave models has improved considerably. Several models have been routinely producing good quality wave estimates globally since the mid-1980s. The verifications of wind-wave models have mainly focused on the evaluation of the error of the significant wave height H{sub s} estimates. However, for wave energy purposes, the main parameters to be assessed are the wave power P{sub w} and the mean (energy) period T{sub e}. Since P{sub w} is proportional to H{sub s}{sup 2}T{sub e}, its expected error is much larger than for the single-wave parameters. This paper summarizes the intercomparison of two wind-wave models against buoy data in the North Atlantic and the Mediterranean Sea to select the most suitable one for the construction of an Atlas of the wave energy resource in European waters. A full verification in the two basins of the selected model--the WAM model, ...
In this paper a prototype of Requirement Tracking and Verification System(RTVS) for a Distributed Control System was implemented and tested. The RTVS is a software design and verification tool. The main functions required by the RTVS are managing, tracking and verification of the software requirements listed in the documentation of the DCS. The analysis of DCS software design procedures and interfaces with documents were performed to define the user of the RTVS, and the design requirements for RTVS were developed. 4 refs., 3 figs. (Author)
Geologic sequestration is currently being practiced and scientifically evaluated as a critical component in a broad strategy, comprising new practices and technologies, for mitigating global climate change due to anthropogenic emissions of CO2. Demonstrating that geologic sequestration of CO2 is safe and effective, and gaining public acceptance of sequestration technologies are critically important in meeting these global climate change challenges. Monitored field-scale demonstrations of geologic sequestration of carbon dioxide will contribute greatly toward growing trust and confidence in the technology; however, pilot demonstrations ultimately will not be the norm for new geological sequestration deployments. Instead, scientists, engineers, regulators, and ultimately the public will rely on numerical simulations to predict the performance of geologic repositories for carbon dioxide sequestration. The U.S. Department of Energy (DOE), through the National ...
This work covers three distinct aspects of deformation and fracture during indentations. In particular, we develop an approach to verification of nanoindentation induced film fracture in hard film/soft substrate systems; we examine the ability to perform these experiments in harsh environments; we investigate the methods by which the resulting deformation from indentation can be quantified and correlated to computational simulations, and we examine the onset of plasticity during indentation testing. First, nanoindentation was utilized to induce fracture of brittle thin oxide films on compliant substrates. During the indentation, a load is applied and the penetration depth is continuously measured. A sudden discontinuity, indicative of film fracture, was observed upon the loading portion of the load-depth curve. The mechanical properties of thermally grown oxide films on various substrates were calculated using two different numerical methods. ...
MAGMA is a FORTRAN computer code designed to viscous flow in in situ vitrification melt pools. It models three-dimensional, incompressible, viscous flow and heat transfer. The momentum equation is coupled to the temperature field through the buoyancy force terms arising from the Boussinesq approximation. All fluid properties, except density, are assumed variable. Density is assumed constant except in the buoyancy force terms in the momentum equation. A simple melting model based on the enthalpy method allows the study of the melt front progression and latent heat effects. An indirect addressing scheme used in the numerical solution of the momentum equation voids unnecessary calculations in cells devoid of liquid. Two-dimensional calculations can be performed using either rectangular or cylindrical coordinates, while three-dimensional calculations use rectangular coordinates. All derivatives are approximated by finite differences. The incompressible Navier-Stokes ...
In the recent work [Proc. of SPIE 7801, 7801-2/1-12 (2010), Opt. Eng. 50(5) (2011), in press], we have reported on improvement of the Developmental Long Trace Profiler (DLTP), a slope measuring profiler available at the Advanced Light Source Optical Metrology Laboratory, achieved by replacing the bulk pentaprism with a mirror based pentaprism (MBPP). An original experimental procedure for optimal mutual alignment of the MBPP mirrors has been suggested and verified with numerical ray tracing simulations. It has been experimentally shown that the optimally aligned MBPP allows the elimination of systematic errors introduced by inhomogeneity of the optical material and fabrication imperfections of the bulk pentaprism. In the present article, we provide the analytical derivation and verification of easily executed optimal alignment algorithms for two different designs of mirror based pentaprisms. We also provide an analytical description for the ...
The Water Frame work Directive (December 2000) proposes integrated water management in regard to both quality and quality. A mathematical model has therefore been produced at the CEIT and EPTISA research centre, in collaboration with the Ebro Hydrographic. Confederation (CHE), to predict water quality and thus begin integrated management of it in the river basins. A description is given of the characteristics of the simulation tool. The hydraulic model is based on the numerical (weighted, four-point implicit) resolution of the complete Saint Venant equations. The quality model is based on the IWA River Water Quality Model Number 1 which has clear advantages (consistency, mass balance and easy integration with the biological models of the waste water treatment plants and the collector networks compared to traditional models. The experimental validation, which includes calibration in wintertime of the hydraulic and quality models most representative coefficients was ...
The opportunity of exposure to high-energy radiation up to GeV is increasing as in civilian aircrafts and at particle accelerators. The transport of such energetic particle is still difficult to describe precisely and thus verification by measurement using a well characterized instrument is indispensable for reliable dosimetry. However, no reference calibration field has been established for the high-energy range. We thus propose to use a facility at the summit of Mt. Fuji (3776 m in altitude; N35.36o, E138.73o), the highest place in Japan, for characterization of radiation instruments that are possibly used in high-energy radiation fields. For demonstration of the effectiveness, two moderator-type neutron monitors (NCN1 and WENDI-II) having different energy response functions were employed for cosmic-ray neutron measurements in the summer of 2009. In comparison with numerically simulated values, it was found that the extended energy neutron ...
The problem in perturbation theory in general relativity is finding a natural gauge which simplifies the equations considerably. We solved the first and second order perturbation equations in the ''Lorentz gauge'' using the two-timing method. The equations were deduced from the equations of Einstein in the presence of a matter energy-momentum tensor of a perfect fluid with equation of state p = (#gamma#-1) rho. It is found that the 0--0 component of the first order equations together with the gauge conditions are consistent with the Bianchi type V model, without axial symmetry. It represents a ''ground state'' situation of the Bianchi type IX model (Mixmaster model.) The second order equations, describing the reaction back of the gravitational waves on the slowly varying background, give rise to rotation and will disturb the isotropization mechanism. The numerical solutions show all the features which are expected to appear. Moreover, it is ...
Several configurations of moderating and shielding materials have been designed and measured on the LVR-15 reactor for boron neutron capture therapy (BNCT) purposes. To determine the neutron and gamma ray space-energy distributions in the cylindrical geometry, the two-dimensional code DOT with the coupled neutron-gamma data library DLC-36 was used. The experimental verification of the beam parameters was performed in the LVR-15 reactor thermal column empty space with layers of graphite, aluminium, alumina, lead and bismuth. Attention was paid to establishing techniques and instrumentation for monitoring the neutron and gamma ray dose and beam quality. The thermal and epithermal flux densities were measured by activation foils, the neutron spectrum was determined with a Bonner spectrometer and gamma ray background with a scintillation spectrometer. The distribution of thermal neutrons in the human head phantom was mapped with a small ...
Several configurations of moderating and shielding materials have been designed and measured on the LVR-15 reactor for boron neutron capture therapy (BNCT) purposes. To determine the neutron and gamma ray space-energy distributions in the cylindrical geometry, the two-dimensional code DOT with the coupled neutron-gamma data library DLC-36 was used. The experimental verification of the beam parameters was performed in the LVR-15 reactor thermal column empty space with layers of graphite, aluminium, alumina, lead and bismuth. Attention was paid to establishing techniques and instrumentation for monitoring the neutron and gamma ray dose and beam quality. The thermal and epithermal flux densities were measured by activation foils, the neutron spectrum was determined with a Bonner spectrometer and gamma ray background with a scintillation spectrometer. The distribution of thermal neutrons in the human head phantom was mapped with a small ...
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...
This paper describes a radiation shield verification survey of a large hot cell at the Fast Flux Test Facility (FFTF). The following aspects of the shield test are discussed: description of the FFTF; description of the hot cell; the test procedures; radiation protection, and the test results.
Purpose:To investigate the clinical usage of dose verification of Helical Tomotherapy plans by using 2D-array ion chambers, and to develop an efficient way to validate the dose delivered...Full Text Available
Prior to this at TRW, Mr. Schier managed flight software development on the MILSTAR Communications Payload and led integration and verification work on ...
Observations show the ubiquitous presence of propagating magnetohydrodynamic (MHD) kink waves in the solar atmosphere. Waves and flows are often observed simultaneously. Due to plasma inhomogeneity in the perpendicular direction to the magnetic field, kink waves are spatially damped by resonant absorption. The presence of flow may affect the wave spatial damping. Here, we investigate the effect of longitudinal background flow on the propagation and spatial damping of resonant kink waves in transversely nonuniform magnetic flux tubes. We combine approximate analytical theory with numerical investigation. The analytical theory uses the thin tube (TT) and thin boundary (TB) approximations to obtain expressions for the wavelength and the damping length. Numerically, we verify the previously obtained analytical expressions by means of the full solution of the resistive MHD eigenvalue problem beyond the TT and TB approximations. ...
This document describes the High Performance Electrical Modeling and Simulation (HPEMS) Global Verification Test Suite (VERTS). The VERTS is a regression test suite used for verification of the electrical circuit simulation codes currently being developed by the HPEMS code development team. This document contains descriptions of the Tier I test cases.
This document describes the High Performance Electrical Modeling and Simulation (HPEMS) Global Verification Test Suite (VERTS). The VERTS is a regression test suite used for verification of the electrical circuit simulation codes currently being developed by the HPEMS code development team. This document contains descriptions of the Tier I test cases.
This book is not a traditional handbook. Engineers in industry need up-to-date, accessible information on the applications of heat and mass transfer. This book is the answer. Contents include: (1) emphasis on applications in thermal design and computer solutions of thermal engineering problems; (2) an introduction to the use of the Second Law of Thermodynamics in analysis, optimization, and economics; (3) information on topics of current interest--in a form convenient and accessible to the average engineer; (4) three chapters of background material--enough to review the basic principles needed to understand specific thermal applications; and (5) extensive treatment of computational tools and numerical analysis.
In this paper, we calculated the radioactive concentration distribution of radioactive waste water, the temperature distribution of drained cooling water and the effect of implement from the Daya Bay Nuclear Power Plant on nearby waters range, discussed and analysed some problems of computational results and computation with Alternating Direction Implicit Method (ADI). The contents of the article included: the establishment of two-dimension tidal current equation, radioactive waste water pollutant dispersion equation and cooling water heat convection diffusion equation, the numerical difference calculation model of tidal current field, concentration field as well as temperature field, effect impingement with ADI method, numerical calculation results. The result of research showed that: when the Daya Bay Nuclear Power Plant is on normal operation and after the low level radioactive waste water and low temperature cooling water have been drained ...
In technical combustors, flow and combustion processes inside the combustion chamber determine the design and also the safety of the plant. A modelling technique was developed at TU Dresden which comprises both numerical simulations and experimental data and thus achieves a high degree of transparency in its visualisation of the processes inside the combustion chambers under investigation. With the experience gained, numerical models of commercial simulation software (FLUENT, CFX) can be validated by measured values, and potential applications of the programs can be investigated. The first stage of experimental modelling consisted in isothermal (cold) modelling in consideration of flow-relevant similarity characteristics. In the reactive, non-isothermal models, the fuel/air ratio and temperature conditions inside the original combustion chamber were modelled as well. In order to obtain detailed data on the combustion conditions at the burner, ...
Until now policy makers and researchers considered the problem of uncertainty and verification to be of minor importance for the Kyoto process. However, the first studies that recently appeared on uncertainty estimation of carbon accounting reveal that uncertainties of the reported emissions on the country level are large. In an environment of such large uncertainties, verification of emission reductions must be viewed as a crucial mechanism to secure the very functioning of the Protocol. The paper provides a set of tools to strategically deal with the problem of uncertainty and verification under the Kyoto Protocol. This is done by: providing an overview of the instruments to deal with verification (no-, trend-, level- and top-down/bottom-up verification under PCA and FCA); compute costs scenarios for those instruments under various flexibility scenarios; and providing a short ...
Data processing method was studied for mise-a-la-masse survey. Mise-a-la-masse method using wells as current sources measures resultant ground surface potential difference, and detects underground local resistivity anomaly. To extract resistivity anomaly largely different from surroundings, the anomaly is extracted as difference between the estimated value of regular resistivity structure (background) and potential difference or apparent resistivity. The following three approximations were attempted to estimate the background: the theoretical equation assuming isotropic homogeneous resistivity structure, that assuming horizontal multi-layered structure and the exponential function of distance from linear electrode for apparent resistivity, and these were compared with each other by numerical model experiment. The data processing method which determines the resistivity structure of the background and the ...
This paper presents the regulatory experience gained from Wolsong Units 2,3 and 4 - Special Safety System Instrumentation Uncertainty for Trip Setpoint and Allowable Values. The equipment diversity method for the defense against common mode failure was applied to the transmitters of shutdown system number 2. However the Units experienced an unexpected drift problem with which the performance did not meet the Technical Specification (Tech Spec) Surveillance Requirements (SR). Discussed are the background, status and corrective actions, regulatory positions and issues to be solved for the drift problem. It was an instrument uncertainty methodology that the designer of safety system should have shown when the drift problem occurred. For deeper understanding of the problem, we present the background of Tech Spec SR for setpoints in Korean PWR and in CANDU reactors. The Setpoint Verification Test(SVT) and Calibration Test(CT) ...
Martin Marietta Energy Systems, Inc. (Energy Systems) manages a closed hazardous waste disposal unit, Chestnut Ridge Security Pits (CRSP), in the form of two trenches and several auger-holes, located on top of the eastern portion of Chestnut Ridge at the Department of Energy (DOE) Oak Ridge Y-12 Plant in Tennessee. The groundwater monitoring system for the unit presently consists of a network of upgradient and downgradient monitor wells. To investigate the discharge of groundwater to springs and streams. An initial dye-tracer study was conducted during the driest part of 1990. The dye was detected at some of the monitoring sites, but verification was necessary due to the proximity of some sites to extraneous dye sources. A second dye-tracer was conducted during the wet weather season. The actual test commenced during the first week of February 1992 with a 4-week baseline monitoring period to determine the inherent variability of the emission spectra within the ...
In the context of safety assessment of radioactive waste repositories, complex radionuclide transport models covering key safety-relevant processes play a major role. In recent Swiss safety assessments, such as Kristallin-I, an important drawback was the limitation in geosphere modelling capability to account for geosphere heterogeneities. In marked contrast to this limitation in modelling capabilities, great effort has been put into investigating the heterogeneity of the geosphere as it impacts on hydrology. Structural geological methods have been used to look at the geometry of the flow paths on a small scale and the diffusion and sorption properties of different rock materials have been investigated. This huge amount of information could however be only partially applied in geosphere transport modelling. To make use of these investigations the 'PICNIC project' was established as a joint cooperation of PSI/Nagra and QuantiSci to provide a new geosphere transport ...
In the past few decades the need for improved nuclear reactor safety analyses has led to a rapid development of advanced methods for multidimensional thermal-hydraulic analyses. These methods have become progressively more complex in order to account for the many physical phenomena anticipated during steady state and transient Light Water Reactor (LWR) conditions. The advanced thermal-hydraulic subchannel code COBRA-TF (Thurgood, M. J. et al., 1983) is used worldwide for best-estimate evaluations of the nuclear reactor safety margins. In the framework of a joint research project between the Pennsylvania State University (PSU) and AREVA NP GmbH, the theoretical models and numerics of COBRA-TF have been improved. Under the name F-COBRA-TF, the code has been subjected to an extensive verification and validation program and has been applied to variety of LWR steady state and transient simulations. To enable F-COBRA-TF for industrial applications, ...
Previously, an analytical dose calculation algorithm for MLC-based radiotherapy was developed and commissioned, which includes a detailed model of various MLC effects as a unique feature [1]. The algorithm was originally developed as an independent verification of the treatment planning system's dose calculation and it explicitly modeled spatial and depth dependent MLC effects such as interleaf transmission, the tongue-and-groove effect, rounded leaf ends, MLC scatter, beam hardening, and gradual MLC transmission fall-off with increasing off-axis distance. Originally the algorithm was implemented in Mathematica trademark (Wolfram). To speed up the calculation time and to be able to calculate high resolution 2D dose distributions within a reasonable time frame (<2 s) the algorithm needs to be optimized and to be embedded in a user friendly environment. To achieve this goal, the dose calculation model is implemented in Visual Basic 6.0, which decreases the ...
The microbial transport simulator (MTS) is a three-dimensional, three-phase, multiple-component numerical model that permits the study of the transport of microorganisms and nutrients in porous media. Microbial parameters incorporated into MTS include: Microbial growth and decay, microbial deposition, chemotaxis, diffusion, convective dispersion, tumbling, and nutrient consumption. Governing equations for microbial and nutrient transport are coupled with continuity and flow equations under conditions appropriate for a black oil reservoir. The model`s mathematical formulations and preparation procedures of data files for conducting simulations using MTS are described. A general background of microbial transport simulation is given in Section I and the governing equations, mechanisms, and numerical solutions of MTS are given in Section II. Explanations for preparing an input data file with reservoir and microbial transport ...
This manuscript contains the lecture notes for a course taught from July 7th through July 11th at the 1997 Numerical Analysis Summer School sponsored by C.E.A., I.N.R.I.A., and E.D.F. The subject area was chosen to support the general theme of that year`s school which is ``Multiscale Methods and Wavelets in Numerical Simulation.`` The first topic covered in these notes is a description of the problem domain. This coverage is limited to classical PDEs with a heavier emphasis on hyperbolic systems and constrained hyperbolic systems. The next topic is difference schemes. These schemes are the foundation for the adaptive methods. After the background material is covered, attention is focused on a simple patched based adaptive algorithm and its associated data structures for square grids and hyperbolic conservation laws. Embellishments include curvilinear meshes, embedded boundary and overset meshes. Next, several strategies for ...
The PLANCK SURVEYOR is a European Space Agency satellite mission to image the very faint anisotropies in the temperature of the Cosmic Microwave Background (CMB) radiation. Maynooth is actively participating in an international collaboration of scientists involved with the optical design of the High Frequency Instrument (HFI). This paper outlines research which has been undertaken in Maynooth concerned with numerical modelling of the optical characteristics of the multi-frequency array of detectors making up the HFI instrument. In the study the commercial software package ZEMAX was used to model the coupling of the focal plane HFI detectors to the PLANCK telescope. This package is particularly useful in the optical design of PLANCK because of the powerful optimisation features of the software. It is thus possible to readily determine the optimum positioning of the detectors in the focal plane of the telescope. Although the package is based on a ...
The problem in perturbation theory in general relativity is finding a natural gauge which simplifies the equations considerably. We solved the first and second order perturbation equations in the ''Lorentz gauge'' using the two-timing method. The equations were deduced from the equations of Einstein in the presence of a matter energy-momentum tensor of a perfect fluid with equation of state p = (..gamma..-1) rho. It is found that the 0--0 component of the first order equations together with the gauge conditions are consistent with the Bianchi type V model, without axial symmetry. It represents a ''ground state'' situation of the Bianchi type IX model (Mixmaster model.) The second order equations, describing the reaction back of the gravitational waves on the slowly varying background, give rise to rotation and will disturb the isotropization mechanism. The numerical ...
With an objective to discuss applicability of resistivity imaging using electromagnetic migration to detection of underground cavity, an applicability test was carried out on calculation of a numerical model and measurement data. By using the numerical model, a calculation was performed on a hypothetical case that a cubic cavity with sides each at 40 m exists in a homogenous medium of 200 ohm-m, with the cavity top located 20 m below the ground surface. As a result, it was possible to structure in a very short calculation time an image of the cavity which cannot be identified by one-dimensional inverse analysis. In the case of this cavity, a center of the image was structured on its lower face. It was shown that a location to indicate the image must be changed according to difference in the measurement locations. In a test on data measured in an underground cavity in the city of Utsunomiya, Tochigi Prefecture, it was found that the result may ...
This standard establishes requirements, verification criteria, and contractor tasks for electromagnetic effects protection of airborne, ground, and support systems. These effects include electromagnetic compatibility, electromagnetic interference, lightni...
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The present authors have previously developed a new method for Probabilistic Fracture Mechanics (PFM), which they call Recursive Distribution (RD) method. The method is based on the construction of the Lebesgue-Stieltjes measure through a deterministic mapping defining a crack growth process. In the present paper, its theoretical background is first discussed, and the Lebesgue decomposition of the measure is given. Then a numerical example of a Light Water Reactor (LWR)`s piping problem is solved by the present method, and the results are compared with those of the Monte Carlo (MC) method. In addition to leakage probability, a variation in stress cycles of the marginal distribution of an aspect ratio of a semi-elliptical surface crack is calculated, which will be used in a study on LBB evaluation.
An image-analysis system, based on commercially available data visualization software (IDL [1]), allows convenient interaction with image data while still providing calculated beam parameters at a rate of up to 2 Hz. Image data are transferred from the IOC to the workstation via EPICS [2] channel access. A custom EPICS record was created in order to overcome the channel access limit of 16k bytes per array. The user can conveniently calibrate optical transition radiation (OTR) and fluorescent screens, capture background images, acquire and average a series of images, and specify several other filtering and viewing options. The images can be saved in either IDL format or APS-standard format (SDDS [3]), allowing for rapid postprocessing of image data by numerous other software tools.
As part of three ongoing research projects, the Gas Research Institute (GRI) is studying the natural gas industry`s impacts on wetlands and how to manage operations so that impacts can be minimized or eliminated. The objective of the first project is to gain a better understanding of the causes and processes of wetland loss in the Louisiana deltaic plain and what role gas pipeline canals play in wetland loss. On the basis of information gathered from the first projects, management and mitigation implications for pipeline construction and maintenance will be evaluated. The objective of the second project is to assess the floral and faunal communities on existing rights-of-way (ROWs) that pass through numerous types of wetlands across the United States. The emphasis of the project is on pipelines that were installed within the past five years. The objective of the third project is to evaluate the administrative, jurisdictional, technical, and economic issues of ...
The next decade promises an observational revolution which will change cosmology forever. The precise measurement of the angular anisotropy of the cosmic microwave background should specify to a few percent all of the parameters of the cosmological model which effect astrophysics. The growth of structure will then be determined (but not yet observed) until gravitational collapse becomes highly non-linear and stars, galaxies and active galactic nuclei (AGN) form. These processes are hard to model with basic physics because they are complex and allow a rich variety of expression. Instead observations will determine when the first stars and quasars formed, and how and when galaxies assembled. If we can reconcile the numerous contradictions which characterize the subject today, cosmology will become a mature subject, founded on the agreement between detailed, inclusive and realistic models, which make precise predictions, and the wealth of new data ...
We study the phonon fluxes emitted when the condensate velocity crosses the speed of sound, i.e., in backgrounds which are analogue to that of a black hole. We focus on elongated one dimensional condensates, and on stationary flows. Our theoretical analysis and numerical results are based on the Bogoliubov-de-Gennes equation without any further approximation. The spectral properties of the fluxes and of the long distance density-density correlations are obtained, with and without an initial temperature. In realistic conditions, we show that the condensate temperature dominates the fluxes, and thus hides the presence of the spontaneous emission (the Hawking effect). We also explain why the temperature amplifies the long distance correlations which are intrinsic to this effect. This confirms that the correlations pattern offers a neat signature of the Hawking effect. Optimal conditions to observe the pattern are discussed.
A possibility of geophysical measurements using the large scale laser interferometrical gravitational wave antenna is discussed. An interferometer with suspended mirrors can be used as a gradiometer measuring variations of an angle between gravity force vectors acting on the spatially separated suspensions. We analyze restrictions imposed by the atmospheric noises on feasibility of such measurements. Two models of the atmosphere are invoked: a quiet atmosphere with a hydrostatic coupling of pressure and density and a dynamic model of moving region of the density anomaly (cyclone). Both models lead to similar conclusions up to numerical factors. Besides the hydrostatic approximation, we use a model of turbulent atmosphere with the pressure fluctuation spectrum f^{-7/3} to explore the Newtonian noise in a higher frequency domain (up to 10 Hz) predicting the gravitational noise background for modern gravitational wave detectors. Our estimates show ...
Martin Marietta Energy Systems, Inc. (Energy Systems) manages a closed hazardous waste disposal unit, Chestnut Ridge Security Pits (CRSP), in the form of two trenches and several auger-holes, located on top of the eastern portion of Chestnut Ridge at the Department of Energy (DOE) Oak Ridge Y-12 Plant in Tennessee. The groundwater monitoring system for the unit presently consists of a network of upgradient and downgradient monitor wells. To investigate the discharge of groundwater to springs and streams, Energy Systems, through Geraghty and Miller, Inc., conducted an initial dye-tracer study during the driest part of 1990. The dye was detected at some of the monitoring sites, but verification was necessary due to the proximity of some sites to extraneous dye sources. Based on the results of the initial study, Energy Systems recommended to the Tennessee Department of Environment and Conservation (TDEC) in the 1990 Groundwater Quality Assessment Report (GWQAR) (HSW ...
The Comprehensive Nuclear-Test-Ban-Treaty (CTBT), which was opened for signature in 1996, bans all nuclear explosions in all environments. Republic of Korea has been working to monitor compliance with CTBT by deterring and detecting any nuclear explosions conducted anywhere on Earth. For the verification of CTBT, several techniques are implemented. Radionuclide monitoring is of particular importance since it is the only method which can provide absolute assurance that a nuclear detonation has occurred
18-Months cycle reload design verifications of Daya Bay NPS is briefly described. It was attempted giving the description of analysis scope and key technology for a nuclear power plant which will be changed fuel management strategy from one year to 18-months cycle
To assure quality of safety critical software, software should be developed in accordance with software development procedures and rigorous software verification and validation should be performed. Software verification is the formal act of reviewing, testing of checking, and documenting whether software components comply with the specified requirements for a particular stage of the development phase[1]. New software verification methodology was developed and was applied to the Shutdown System No. 1 and 2 (SDS1,2) for Wolsung 2,3 and 4 nuclear power plants by Korea Atomic Energy Research Institute(KAERI) and Atomic Energy of Canada Limited(AECL) in order to satisfy new regulation requirements of Atomic Energy Control Boars(AECB). Software verification methodology applied to SDS1 for Wolsung 2,3 and 4 project will be described in this paper. Some errors were found by this methodology during the software ...
To assure quality of safety critical software, software should be developed in accordance with software development procedures and rigorous software verification and validation should be performed. Software verification is the formal act of reviewing, testing of checking, and documenting whether software components comply with the specified requirements for a particular stage of the development phase[1]. New software verification methodology was developed and was applied to the Shutdown System No. 1 and 2 (SDS1,2) for Wolsung 2,3 and 4 nuclear power plants by Korea Atomic Energy Research Institute(KAERI) and Atomic Energy of Canada Limited(AECL) in order to satisfy new regulation requirements of Atomic Energy Control Boars(AECB). Software verification methodology applied to SDS1 for Wolsung 2,3 and 4 project will be described in this paper. Some errors were found by this methodology during the software ...
Plasma neutralization of an intense ion pulse is of interest for many applications, including plasma lenses, heavy ion fusion, cosmic ray propagation, etc. An analytical electron fluid model has been developed based on the assumption of long charge bunches (l{sub b} >> r{sub b}). Theoretical predictions are compared with the results of calculations utilizing a particle-in-cell (PIC) code. The cold electron fluid results agree well with the PIC simulations for ion beam propagation through a background plasma. The analytical predictions for the degree of ion beam charge and current neutralization also agree well with the results of the numerical simulations. The model predicts very good charge neutralization (>99%) during quasi-steady-state propagation, provided the beam pulse duration {tau}{sub b} is much longer than the electron plasma period 2{pi}/{omega}{sub p}, where {omega}{sub p} = (4{pi}e{sup 2}n{sub p}/m){sup 1/2} is ...
Producing nuclear energy in order to reduce anthropic CO{sub 2} emission and to meet high energy demand, implies three conditions to the nuclear plants of the IV. generation: safety improvements, radioactive waste minimization, and fuel breeding for a sustainable use of the resources. The Thorium fuel cycle used in Molten Salt Reactors seems promising. Many numerical studies based on probabilistic codes are carried out in order to analyse the behaviour of such reactors. Nevertheless, one of the most important parameters is badly known: the alpha ratio of {sup 233}U, ratio of the neutron capture cross section to fission one for {sup 233}U. This key-parameter is necessary to calculate the breeding ratio and thus, the deployment capacities of those reactors. This Ph-D thesis was intended to prepare a precise measurement of the alpha ratio of {sup 233}U between 1 eV and 10 keV. Preliminary measurements have been performed on the experimental platform PEREN. This ...
The Canadian wind energy industry is experiencing rapid and unprecedented growth. The year 2006 saw the installation of 534 MW of wind energy across Canada, representing approximately $1 billion in new investment. It is anticipated that the wind energy industry will help to create jobs and training opportunities for many Canadians, as well as provide ongoing economic benefits to local communities through municipal tax and land lease payments. However, many challenges remain if Canada is to meet, or exceed, its objective of a total of 10,000 MW in installed wind energy by 2015. This conference provided a forum for wind industry member, academics and representatives of both governmental and non-governmental agencies to discuss issues related to wind energy development. The conference was divided into 3 streams. The policy stream examined issues related to the Canadian Wind Power Production Incentive (WPPI) program, as well as various federal policies regarding environmental assessments ...
Building complex knowledge based applications requires encoding large amounts of domain knowledge. After acquiring knowledge from domain experts, much of the effort in building a knowledge base goes into verifying that the knowledge is encoded correctly. We consider the problem of verifying hybrid knowledge bases that contain both Horn rules and a terminology in a description logic. Our approach to the verification problem is based on showing a close relationship to the problem of query containment. Our first contribution, based on this relationship, is presenting a thorough analysis of the decidability and complexity of the verification problem, for knowledge bases containing recursive rules and the interpreted predicates =, {le}, < and {ne}. Second, we show that important new classes of constraints on correct inputs and outputs can be expressed in a hybrid setting, in which a description logic class hierarchy is also considered, and we ...
Purpose: The authors have developed a novel technique using an electronic portal imaging device (EPID) to verify the geometrical accuracy of delivery of dose-rate-regulated tracking (DRRT)....Full Text Available
This work deals with a rational vision of stratospheric ozone including the threats on ozone layer, the verifications and the fears. After a recalling on the ozone layer history, the authors treats the question of the ultraviolets particularly the beneficial effects. Then an explanation of the ozone layer decrease is given. (O.L.). 29 refs., 6 figs.
The cupola furnace is used to melt scrap steel, pig iron, foundry returns, and alloying additives to a prescribed tapping chemistry and temperature for iron casting applications. The melting process within the cupola is highly complex and not well quantified. The American Foundrymen's Society is developing a mathematical model to aid in the understanding of these processes. This model is reaching maturity, and has been successful in estimating a number of melting parameters. This paper details the results of efforts to verify the model in a controlled system, equipped wit the appropriate sensors, for model verification. The work was performed on a research-scale cupola furnace located at the Department of Energy's Albany Research Center.
Lyman-limit absorption systems can play many important roles during and after cosmological reionization. Unfortunately, due to the prohibitively large dynamic range required, it is impossible to self-consistently include these systems in cosmological simulations. Using fast and versatile semi-numeric simulations, we systematically explore the spatial distribution of absorption systems during and following reionization. We self-calibrate the resulting number of absorbers to the mean free path (mfp) of the ionizing ultraviolet background (UVB), and present results at a given mfp and neutral hydrogen fraction. We use a simple optical depth criterion to identify the locations of absorbers. Our approach is fairly robust to uncertainties such as missing subgrid structure. Unlike at lower redshifts where the UVB is relatively uniform, at higher redshifts the fluctuations in the UVB and the HII morphology of reionization can drive the large-scale ...
As part of three ongoing research projects, the Gas Research Institute (GRI) is studying the natural gas industry's impacts on wetlands and how to manage operations so that impacts can be minimized or eliminated. The objective of the first project is to gain a better understanding of the causes and processes of wetland loss in the Louisiana deltaic plain and what role gas pipeline canals play in wetland loss. On the basis of information gathered from the first projects, management and mitigation implications for pipeline construction and maintenance will be evaluated. The objective of the second project is to assess the floral and faunal communities on existing rights-of-way (ROWs) that pass through numerous types of wetlands across the United States. The emphasis of the project is on pipelines that were installed within the past five years. The objective of the third project is to evaluate the administrative, jurisdictional, technical, and economic issues ...
Background When assessing the function of the cardiovascular system, cardiac output (CO) is a substantial parameter. For its determination, numerous non-invasive techniques have been proposed in the recent years including inert gas rebreathing (IGR) and impedance cardiography (ICG). The aim of our study was to evaluate whether a novel ICG algorithm (electrical velocimetry) and IGR can be used interchangeably in the clinical setting. Methods A total of 120 consecutive stable patients were included resulting in two pairs of repeated non-invasive cardiac output measurements. Results The mean CO was 5.0???1.2?l/min (range 2.6?8.6?l/min) using IGR and 4.4???1.1?l/min (1.7?7.4?l/min) using ICG, respectively. Bland?Altman analysis revealed an acceptable agreement with a mean bias of 0.6???1.2?l/m...
Blade fatigue life is an important element in determining the economic viability of the Vertical-Axis Wind Turbine (VAWT). A principal source of blade fatigue is thought to be the stochastic (i.e., random) aerodynamic loads created by atmospheric turbulence. This report describes the theoretical background of the VAWT Stochastic Aerodynamic Loads (VAWT-SAL) computer code, whose purpose is to numerically simulate these random loads, given the rotor geometry, operating conditions, and assumed turbulence properties. A Double-Multiple-Stream Tube (DMST) analysis is employed to model the rotor's aerodynamic response. The analysis includes the effects of Reynolds number variations, different airfoil sections and chord lengths along the blade span, and an empirical model for dynamic stall effects. The mean ambient wind is assumed to have a shear profile which is described by either a power law or a logarithmic variation with height above ...
... Title : The Numerical Weather Prediction System at the Italian Air Force Weather Service: Impact of Non-Conventional Observations and Increased ...
The report gives a summary of important developments in numerical weather prediction and discusses their relationship to, and effect on, the practice of synoptic meteorology.
Gel dosimetry is a new dosimetry method applied in radiation therapy. Gel dosimeters consist of a radiation sensitive gel, which can integrate absorbed doses from several radiation sources or beams. The dose to the gel can be evaluated by magnetic resonance imaging (MRI), a procedure that is the focus of the present thesis. A robust tool for the evaluation of the nonuniformity in MRI has been developed, the Deviation Image method. Unlike previously presented methods, the Deviation Image method includes all nonuniformity variations across a phantom surface and is insensitive to stochastic noise. Methods for the estimation of stochastic noise were analyzed in terms of sensitivity to nonuniformities. A method that averages the stochastic noise level over five regions over the phantom surface, and a method that assesses the stochastic noise level from the background, were found to be the methods of choice. Pronounced MR image nonuniformity variation with repetition and ...
Portal verification images were generated from the photon contamination in electron beams produced by a linear accelerator during treatment of patients receiving high-energy electron radiation therapy (8-14 MeV). An experimental storage phosphor system was used to record the images and display them on laser-printed film. Images were obtained from four or more treatment fractions from 21 cases of head and neck cancer. Precision in field placement was estimated by determining the position of a selected anatomic landmark relative to the center of the field for each series of images. The average standard deviation in the field-position measurements was 3.8 mm. Several procedural problems were also detected and corrected after review of the verification images. The results indicate that the emphasis placed on monitoring and control of field-positioning error in high-energy electron treatments should be similar to the emphasis placed on this aspect ...
The Four years of the IMPACT, 'Integrated Modular Plant Analysis and Computing Technology', project Phase 1 have been completed. The verification study of Severe Accident Analysis Code SAMPSON prototype developed in Phase 1 was conducted in two steps. First, each analysis module was run independently and analysis results were compared and verified against separate-effect test data with good results. Second, with the Simulation Supervisory System, up to 11 analysis modules were executed concurrently in the parallel environment (currently, NUPEC uses IBM-SP2 with 72 process elements), to demonstrate the code capability and integrity. The target plant was Surry as a typical PWR and the initiation events were a 10-inch cold leg failure. The analysis is divided to two cases; one is in-vessel retention analysis when the gap cooling is effective (In-vessel scenario test), the other is analysis of phenomena event is extended to ex-vessel due to the Reactor Pressure Vessel ...
For safety evaluations and licensing procedures, fuel rod performance is predicted through model calculations. Due to the complexity of fuel rod performance and the insufficient availability of experimental data, such calculations necessarily reflect inaccuracies and conservatism. For verification and development of more realistic models and submodels, acquisition of reliable on-line data on fuel rod performance characteristics is imperative. The present paper describes the instruments and equipment applied in the Halden Reactor for on-line measurements of fuel rod and assembly power and power distribution, and fuel rod axial and diameter deformation. Recent results from evaluation of such fuel rod deformation measurements, covering fuel rods with different designs, subjected to various modes of operation, including startup ramps, steady state, and power shock, are presented. It is also shown how these data are used for verification and ...
... been possible to prove the existence and uniqueness of a classical solution which tends to the well-known solution of the Stefan problem as the ...
Sur l'origine des chiffres arabes A. Boucenna 1 From the pagination of an Algerian Arabic manuscript of the beginning of the 19th century,we rediscover the original shape that the Arabic numerals had before passing in Europe and underwent the transformation that gave the modern Arabic numerals. This original shape,whose use disappeared completely, proves that these numerals have their origin in the Arabic letters. Contrary to what some hypotheses pretend, particularly those that present them as drifting of Indian characters, the 10 Arabic numerals that we use are, nothing else, 10 Arabic letters more or less modified and taken in the "Abjadi" order. The hypothesis of the Indian origin of the Arabic numerals is revealed a mistake denied by the shape of the Arabic numerals and by the logic of the right to left representation of the numbers and the algorithm of the ...
The purposes of this report are (1) to perform a Verification and Validation (V and V) test for the VIPEX(Vital-area Identification Package EXpert) software and (2) to improve a software quality through the V and V test. The VIPEX was developed in Korea Atomic Energy Research Institute (KAERI) for the Vital Area Identification (VAI) of nuclear power plants. The version of the VIPEX which was distributed is 3.2.0.0. The VIPEX was revised based on the first V and V test and the second V and V test was performed. We have performed the following tasks for the V and V test on Windows XP and VISTA operating systems: ? Testing basic functions including fault tree editing ? Testing all kind of functions ? Research for update from Visual BASIC 6.0 to Visual BASIC 2008
The possibility of developing reactor designs with inherent safety characteristics sufficient to provide walk away safety is receiving additional emphasis in the LMR program. A key element in this effort is the recognition that LMR's possess safety characteristics above and beyond those employed in past safety review processes. Some of these additional safety characteristics are due to reactivity feedback effects caused by small structural movements during hypothetical severe design transients. The effects of these characteristics upon the behavior of the FFTF under such transients has been assessed and is discussed in this paper. The paper also presents a preliminary test matrix which might allow experimental verification of the structural reactivity feedback effects. Such experimental verification should be very useful to innovative designers seeking to optimize inherent safety.
The possibility of developing reactor designs with inherent safety characteristics sufficient to provide ''walk away'' safety is receiving additional emphasis in the LMR program. A key element in this effort is the recognition that LMR's possess safety characteristics above and beyond those employed in past safety review processes. Some of these additional safety characteristics are due to reactivity feedback effects caused by small structural movements during hypothetical severe design transients. The effect of these characteristics upon the behavior of the FFTF under such transients has been assessed and is discussed in this paper. The paper also presents a preliminary test matrix which might allow experimental verification of the structural reactivity feedback effects. Such experimental verification should be very useful to innovative designers seeking to optimize inherent safety. 8 refs., 1 fig., 2 tabs.
We present sufficient conditions that imply duality for the algebras of local observables in all Abelian sectors of all locally normal, irreducible representations of a field algebra if twisted duality obtains in one of these representations. It is verified that the Yukawa/sub 2/ model satisfies these conditions, yielding the first proof of duality for the observable algebra in all coherent charge sectors in this model. This paper also constitutes the first verification of the assumptions of the axiomatic study of the structure of superselection sectors by Doplicher, Haag and Roberts in an interacting model with nontrivial sectors. The existence of normal product states for the free Fermi field algebra and, thus, the verification of the funnel property for the associated net of local algebras are demonstrated.
In this report we focus on some aspects related to modeling and formal verification of embedded systems. Many models have been proposed to represent embedded systems . These models encompass a broad range of styles, characteristics, and application domains and include the extensions of finite state machines, data flow graphs, communication processes and Petri nets. In this report, we have used a PRES+ model (Petri net based Representation for Embedded Systems) as an extension of classical Petri net model that captures concurrency, timing behaviour of embedded systems; it allows systems to be representative in different levels of abstraction and improves expressiveness by allowing the token to carry information. Modeling using PRES+, as discussed above, may be convenient for specifying the input behaviour because it supports concurrency. However, there is no equivalence checking method reported in the literature for PRES+ models to the best of our knowledge. In ...
The ISI (In-Service Inspection) system has been developed so as to maintain the structural integrity of heat transfer tubes in the primary pressurized water cooler in the HTTR (High Temperature Engineering Test Reactor). This system consists of eddy current probes, ultra-sonic probes, insertion and extraction units, positioning unit and so on. Verification and performance tests of the developed ISI system were carried out using mock-up heat transfer tubes in the primary pressurized water cooler. The constitution of the system, R and D results of the inspection probes, and verification and performance test results of the ISI system for heat transfer tubes are described in this paper. (author)
The ISI (In-Service Inspection) system has been developed so as to maintain the structural integrity of heat transfer tubes in the primary pressurized water cooler in the HTTR (High Temperature Engineering Test Reactor). This system consists of eddy current probes, ultra-sonic probes, insertion and extraction units, positioning unit and so on. Verification and performance tests of the developed ISI system were carried out using mock-up heat transfer tubes in the primary pressurized water cooler. The constitution of the system, R and D results of the inspection probes, and verification and performance test results of the ISI system for heat transfer tubes are described in this paper. (author)
The purpose of this study is to investigate on the experimental verification analysis for the pipe whip problems and to obtain the quantitative evaluation technologies for the design technique of pipe whip restraints. These will contribute to the advance of nuclear regulatory technologies and enhance nuclear power plant safety. This study presents the experimental and transient analytical results of pipe whip tests using the 4', 6' diameter pipe and U-shaped restraints. In the tests, the effects of the overhang length, clearance, impact height on the pipe whip behavior of the pipe-restraints were investigated. The transient impact analysis of the pipe-restraint system was conducted by the finite element program ABAQUS. The applicability of the ABAQUS program to the pipe whip analysis is made clear through this analysis.
A method is presented for estimating the background at a given location on a sky map by interpolating the estimated background from a set of concentric annuli which surround this location. If the background is nonuniform but smoothly varying, this method provides a more accurate (though less precise) estimate than can be obtained with a single annulus. Several applications of multi-annulus background estimation are discussed, including direct testing for point sources in the presence of a nonuniform background, the generation of "surrogate maps" for characterizing false alarm rates, and precise testing of the null hypothesis that the background is uniform.
The GASPAR module utilized in MAXIGASP and POPGASP has been verified by hand calculations. The program operates as documented by the NRC [Eckerman et. al. 1980]. Equations used in the code to calculate downwind deposition rates, concentrations in air, on ground surfaces, and in vegetables, meat, and milk are provided in this report.
The detection efficiency of a lithium glass detector was calculated using MCNP code, and the calculation was compared with the published results in Pulsed Sphere Plan. A lithium glass detector of our own was made, and its neutron efficiency was calculated. The calculated neutron efficiency was verified with both pulsed and steady DD neutrons. Characteristics of Neutron response of "6Li detector was discussed. (authors)
Information is presented concerning new trends in licensing; seismic considerations and system structural behavior; TMI-2 risk assessment and thermal hydraulics; statistical assessment of potential accidents and verification of computational methods; issues with respect to improved safety; human factors in nuclear power plant operation; diagnostics and activities in support of recovery; LOCA transient analysis; unresolved safety issues and other safety considerations; and fission product transport.
Information is presented concerning new trends in licensing; seismic considerations and system structural behavior; TMI-2 risk assessment and thermal hydraulics; statistical assessment of potential accidents and verification of computational methods; issues with respect to improved safety; human factors in nuclear power plant operation; diagnostics and activities in support of recovery; LOCA transient analysis; unresolved safety issues and other safety considerations; and fission product transport.
The necessity of the electron beam machine characterization via dose measurement is discussed. It includes a measurement of comprehensive dose distribution (at known X and Z axis) for verification of the machine performance. The acquired data were then used to develop the irradiation parameters such as energy, current, distance, conveyor speed, exposure rate and depth inside product to be irradiated. These parameters will be used as a guide for the routine irradiations. (Author)
Certification as applied to existing computer codes includes the verification and validation process, placing the code in configuration control, establishing user qualification standards and training requirements. All software intended for use in critical calculations must be certified. This report is intended to fulfill the requirements for the certification of the SHIELD, SHLDED, GEDIT, GENPRT, FIPROD, FPCALC, and PROCES modules of the SHIELD system built February, 1992, by W.S. Parks. These modules are used for burnup, cooling, separate, and edit calculations.
There is ample historical verification of 46,XX congenital adrenal hyperplasia (CAH) patients being born with essentially male genitaliawhile outcome information is scant. Prior to glucocorticoid...Full Text Available
A reliable inventory control system was developed at the Fast Flux Test Facility (FFTF) to keep track of the occupancy of 900 refueling facility locations, to compile historical data on the movement of each reactor assembly, and to simulate assembly moves. The simulate capability is valuable because it allows verification of documents before they are issued for use in the plant, and eliminates the possibility of planning illegal or impossible moves. The system is installed on a UNIVAC 1100 computer and is maintained using a data base management system by Sperry Univac called MAPPER.
The requirements are given as placed on the development, procurement, maintenance, and application of software for the creation or processing of data during the design, construction, operation, repair, maintenance and safety-related upgrading of nuclear power plants. The verification and validation processes are highlighted, and the requirements put on the software documentation are outlined. The general quality assurance principles applied to safety analyses are characterized. (J.B.). 1 ref.
The Sodium Storage Facility Project Quality Assurance Plan delineates the quality assurance requirements for construction of a new facility, modifications to the sodium storage tanks, and tie-ins to the FFTF Plant. This plan provides direction for the types of verifications necessary to satisfy the functional requirements within the project scope and applicable regulatory requirements determined in the Project Functional Design Criteria (FDC), WHC-SD-FF-FDC-009.
Accidents from three main practices: medical applications, industrial radiography and industrial irradiators are used to illustrate some common causes of accidents and the main lessons to be learned. A brief description of some of these accidents is given. Lessons learned from the described accidents are approached by subjects covering: safety culture, quality assurance, human factors, good engineering practice, defence in depth, security of sources, safety assessment and monitoring and verification compliance. (author)
The field trial of an unattended monitoring system for SF transfer verification ended in June 2005. The system is aiming to improve the safeguards measures applied during SF transfers and reduce inspection effort currently required by the Operator, NNCA and the IAEA. They were reviewed based on its technical performance and other issues in this paper.
The field trial of an unattended monitoring system for SF transfer verification ended in June 2005. The system is aiming to improve the safeguards measures applied during SF transfers and reduce inspection effort currently required by the Operator, NNCA and the IAEA. They were reviewed based on its technical performance and other issues in this paper.
U.S. Department of Energy (DOE) Policy 450.4, Safety Management System Policy commits to institutionalizing an Integrated Safety Management System (ISMS) throughout the DOE complex as a means of accomplishing its missions safely. DOE Acquisition Regulation 970.5204-2 requires that contractors manage and perform work in accordance with a documented safety management system.
These ten chapters present an overview of floating production, storage and offloading (FPSO) vessels, and examines deep water developments; hydrostatic stability; production, storage and offloading systems; the configuration and structure of flexible risers and umbilicals; the structural and global dynamic analysis of flexible riser and umbilicals; verification of FPSO structural integrity; vessel global loading and rigid body response; environmental loading and vessel response; and mooring systems. (UK)
Due to a leakage from a 12-inch pressurized diesel steel pipe four years ago, an area of approximately 30,000 square meters was contaminated. A pilot study applying the technology of in-situ enhanced bioremediation was conducted. In the study, a field test kit and on-site monitoring equipment were applied for site characterization and treatment verification. Physically, the enhanced bioremediation study consisted of an air extraction and air supply system, and a nutrition supply network. Certain consistent sampling methodology was employed. Progress was verified by daily monitoring and monthly verification. The objective of this study was to evaluate the capabilities of indigenous microorganisms to biodegrade the petroleum hydrocarbons with provision of oxygen and nutrients. Nine extraction wells and eight air sparging wells were installed. The air sparging wells injected the air into geoformation and the extraction wells provided the ...
The objectives of this report are: to demonstrate complete CSSX process flowsheet (proof of concept)--decontamination factor {ge} 40,000, and concentration factor {approx}15; Scientific and technical issues evaluated--stage efficiency, temperature control, hydraulic performance, long time (multi-day) operation, short-term shutdown, effect of solids, and recovery from Cs moving through strip section.
The tritium in transpired water of plant leaves from four locations within site area (2=0.92) with that of measured values indicating that at Tarapur, the contribution to TFWT of plant is only from air activity and pick up through soil route is negligible during the period of study. (author)
High dose rate (HDR) brachytherapy for treating a cervix carcinoma has become popular, because it eliminates many of the problems associated with conventional brachytherapy. In order to improve the clinical effectiveness with HDR brachytherapy, a dose calculation algorithm, optimization procedures, and image registrations need to be verified by comparing the dose distributions from a planning computer and those from a humanoid phantom. In this study, the humanoid phantom was fabricated in order to verify the absolute doses and the relative dose distributions. The measured doses from the humanoid phantom were then compared with the treatment planning system for the dose verification. The humanoid phantom needs to be designed such that the dose distributions can be quantitatively evaluated thermoluminescent dosimeter (TLD) chips with a dimension of 1/8 and film dosimetry with a spatial resolution of <1 mm used to measure the radiation dosages in the phantom. ...
For verification of cow fertility a /sup 3/H radioimmunoassay of progesterone in milk and blood plasma was developed. It is of high specificity and accuracy as well. Extraction of progesterone from milk was facilitated by application of alcohol. Suggested differences in milk and plasma progesterone levels between pregnant and nonpregnant cows could be revealed.
The involvement and relationship of carbon steel corrosion products in the tube denting phenomenon promoted an intensive research effort to: 1) understand, reproduce, and arrest the denting process, and 2) evaluate alternative tube support materials to provide additional corrosion resistance. The paper summarizes a corrosion testing program for the verification of type 405 stainless steel under acid or all volatile treatment conditions.
An Eulerian/Langrangian model was developed to study the two-phase flow in a two-dimensional, axisymmetric, direct-injection diesel engine, under motored and firing conditions. The liquid phase was tracked in a Lagrangian sense using discrete droplet packets (DDP). The gaseous phase was solved using an implicit, iterative, finite-difference, scheme of the control volume variety. Gaseous-phase turbulence was modeled using a compressible two-equation k/epsilon model. Turbulence effects on the liquid phase were modeled by superimposing a randomly oriented turbulent eddy velocity proportional to the root of the turbulent kinetic energy, on each packet's mean relative velocity. Droplet-droplet interactions were neglected. The general knowledge obtained during validation studies, was used to simulate the direct-injection two-stroke diesel engine under motored conditions. The simulation showed that by beginning of the injection, (15/sup 0/ before top dead center: BTDC), the ...
Stochastic simulation has been employed in petroleum reservoir characterization as a modeling tool able to reconcile information from several different sources. It has the ability to preserve the variability of the modeled phenomena and permits transference of geological knowledge to numerical models of flux, whose predictions on reservoir constitute the main basis for reservoir management decisions. Several stochastic models have been used and/or suggested, depending on the nature of the phenomena to be described. Markov Random Fields (MRFs) appear as an alternative for the modeling of discrete variables, mainly reservoirs with mosaic architecture of facies. In this dissertation, the reader is introduced to the stochastic modeling by MRFs in a generic sense. The main aspects of the technique are reviewed. MRF Conceptual Background is described: its characterization through the Markovian property and the equivalence to Gibbs distributions. The ...
We have constructed a Monte Carlo generator (the corresponding FORTRAN code can be obtained from the authors upon request) for lowest-order predictions for the processes {gamma}{gamma}{yields}4f and {gamma}{gamma}{yields}4f{gamma} in the standard model and extensions thereof by an effective {gamma}{gamma}H coupling as well as anomalous triple and quartic gauge-boson couplings. Polarization is fully supported, and a realistic photon beam spectrum can be taken into account. For the processes {gamma}{gamma}{yields}4f all helicity amplitudes are explicitly given in a compact form. The presented numerical results contain, in particular, a survey of cross sections for representative final states and their comparison to results obtained with the program package Whizard/Madgraph. The impact of a realistic beam spectrum on cross sections and distributions is illustrated. Moreover, the size of various contributions to cross sections, such as from weak charged- or ...
We have constructed a Monte Carlo generator (the corresponding FORTRAN code can be obtained from the authors upon request) for lowest-order predictions for the processes #gamma##gamma##->#4f and #gamma##gamma##->#4f#gamma# in the standard model and extensions thereof by an effective #gamma##gamma#H coupling as well as anomalous triple and quartic gauge-boson couplings. Polarization is fully supported, and a realistic photon beam spectrum can be taken into account. For the processes #gamma##gamma##->#4f all helicity amplitudes are explicitly given in a compact form. The presented numerical results contain, in particular, a survey of cross sections for representative final states and their comparison to results obtained with the program package Whizard/Madgraph. The impact of a realistic beam spectrum on cross sections and distributions is illustrated. Moreover, the size of various contributions to cross sections, such as from weak charged- or ...
In this paper, we present an iterative filtering method to estimate the background of noisy spectroscopic data. The proposed method avoids the calculation of the average full width at half maximum (FWHM) of the whole spectrum and the peak regions, and it can estimate the background efficiently, especially for spectroscopic data with the Compton continuum.
BackgroundThis study investigated the knowledge of depression and preference for professional help, medications and treatment methods among Australians of Chinese-speaking background,...Full Text Available
We have made preliminary estimates of charged particles background at the 100x100 GeV Photon Linear Collider with ultimate luminosity. The charged particles background due to electromagnetic processes is located mainly in the small-angle range of the detector. At large angles, the number of background particles is much smaller. Analysis of the background (at least, in the range under consideration) shows that background conditions for the VLEPP-based Photon Linear Collider are better than at the VLEPP electron-positron collider. ((orig.)).
Full text: The ITWG was first formed in 1995 for the purpose of fostering international cooperation for combating illicit trafficking of nuclear materials. The initial focus for the ITWG was on the development of nuclear forensics to help answer attribution questions regarding nuclear materials of unknown origin. More recently, the ITWG has also expanded its focus to include detection of nuclear materials during transit. This paper presents some of the key developments by this group and their potential impact for combating nuclear smuggling. The initial focus of the ITWG was to write a status report on international cooperation on nuclear smuggling forensic analysis. This 26-page report summarized previous work on nuclear forensics and gave an initial analysis on prioritizing techniques and methods for forensic analysis regarding source and route attribution. This report was submitted to the G-8 countries, and shortly thereafter, nuclear forensics was endorsed at the Moscow Summit in ...
BackgroundA large and increasing part of the European population has a history of migration. Germany, for example, is home to about 15 million people with migrant background, which...Full Text Available
Numerical calculations of static, switched, and radiofrequency (RF) electromagnetic (EM) fields considering the geometry and EM properties of the human body are used increasingly in MRI to explain...Full Text Available
This report presents a summary of highlights of the year 1978. It then discusses: Research and development in numerical analysis and prediction systems; Techniques, development and application of new products; Analysis-forecast systems in operation use du...
Pfister, Robert M. (Lamont Geological Observatory, Palisades, N.Y.), and Paul R. Burkholder. Numerical taxonomy of some bacteria isolated from Antarctic and tropical seawaters. J....Full Text Available
Animals in a variety of taxa discriminate between a greater quantity and a lesser quantity of the same object, an ability that is referred to as relative numerousness judgment. For example,...Full Text Available
Coke-fired cupola furnaces were improved and made suitable for the production of high-quality casting melts by numerous additional devices. Moreover, they were equipped with environmental protection systems with numerous dust separation devices and afterb...
The vortex-excited dynamics of a uniform pivoted cylinder in uniform and sheared flow was investigated experimentally. The experiments were numerically simulated using a diffusive Van der Pol oscillator model developed by Balasubramanian & Skop recently. Salient features of the experimental investigations and the numerical simulations are presented here. Comparisons between the experimentally recorded and numerically predicted structural response to vortex-excited vibrations, power spectral density measurements of near-wake velocity fluctuations and lock-in ranges are made. A comparison of the numerical predictions and the experimental data reveals good agreement.
The radiative transport problem is cast in integral form using a transport kernel. The transport kernel has an explicit representation in terms of a Feynman Path Integral over all paths between selected points in a volume. This representation is setup in detail. Numerical evaluation of this Path Integral is formulated with a Frenet-Serret based procedure for generating valid random paths, and with a numerical evaluation of the weight for each valid path. Very early sanity checks of a numerical implementation are reported. Approaches to optimization are identified. (authors)
A physical model of free-electron laser (FEL) amplifier with variable-parameter wiggler magnets for one-dimensional numerical simulation is presented and a numerical example is given. The wiggler parameters, efficiency of energy conversion between electron beam and laser field, laser intensity, phase-space distributions and energy spectrum of electrons are computed. The period of synchronous oscillation and saturation value of laser intensity agree with estimated one.
A boundary value problem for Laplace?s equation in a bounded two-dimensional domain filled with a piecewise homogeneous medium is considered. The boundary of the inhomogeneity is assumed to be unknown. The inverse problem of determining the inhomogeneity boundary and the solution of the equation given the solution and its normal derivative on the boundary of the domain is discussed. Numerical methods are proposed for solving the inverse problem, and the results of numerical experiments are presented.
The enhancement of longitudinal heat transfer by means of fluid pulsation in a pipe has been investigated analytically and numerically, including the transient state. The effects of pulsation amplitude, frequency, and pipe length on thermal properties such as effective thermal diffusivity and delay time are clarified. Their effects on numerical calculations are also presented and suggestions for efficient numerical calculations of this problem are made concerning the combination of parameters.
An numerical method was developed for measuring radiant temperature using a set of absorption-foils coupled to soft x ray streak camera, SXRSC, in laser plasma experiments. An numerical code, SCC, was given. An x-ray intensity ratio vs temperature was calculated for Parylene, C_3H_6, Mylar and Aluminium. A suitable range of the measuring temperature was discussed to some absorber.
This paper presents a case study in the design and implementation of a numerical weather prediction model on a supercomputer (CRAY-1). Following a historical introduction to the evolution of the model, the governing equations of the model are presented and the numerical solution of these forecast equations is described. A brief tutorial on the architecture of the CRAY-1 is presented with a discussion of how it affects the choice of algorithms and code design of the model. A summary of the advantages gained by use of the vector aspects of the CRAY-1 is included.
Numerical simulations of compressible flows are commonly based on the Euler equations when effects of viscosity are thought to be negligible. These equations admit singular solutions, even in cases where the initial and boundary conditions are smooth. So-called ''Euler solvers'' rely on numerical dissipation, explicitly or implicitly present in the scheme, to regularize the problem, such that physical solutions are selected.
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.
Processing of symbolic sequences represented by mapping of symbolic data into numerical signals is commonly used in various applications. It is a particularly popular approach in genomic and proteomic sequence analysis. Numerous mappings of symbolic sequences have been proposed for various applications. It is unclear however whether the processing of symbolic data provides an artifact of the numerical mapping or is an inherent property of the symbolic data. This issue has been long ignored in the engineering and scientific literature. It is possible that many of the results obtained in symbolic signal processing could be a byproduct of the mapping and might not shed any light on the underlying properties embedded in the data. Moreover, in many applications, conflicting conclusions may arise due to the choice of the mapping used for numerical representation of symbolic data. In this paper, we present a ...
The pressurized Heavy Water Reactor (PHWR) consists of horizontal calandria vessel containing a large number of pressure tubes (fuel channels) connected to the reactor inlet and outlet headers by individual feeders. Coolant flow distribution among the pressure tubes play a vital role in extraction of thermal power. For these reactors one of the design objectives is to achieve uniform coolant outlet temperatures by providing coolant flows according to the channel power. This is achieved by the design process known as feeder sizing. This basically consists of accounting for the individual channel power and centre line geometry of individual feeder and iteratively adjusting the feeder hydraulic resistances within the design constraints such as limiting flow velocities, channel flows. Recently, the first unit of 540 MWe i.e Tarapur Atomic Power Project (unit 4) has been commissioned. This paper discusses the verification of the coolant flow distribution in the core ...
There are 4 CANDU reactors at Wolsung site together with a spent fuel dry storage associated with unit 1. These CANDU reactors, classified as On-Load Reactor (OLR) for Safeguards application, change 16- 24 fuel bundles with fresh fuel in everyday. Especially, the spent fuel bundles are transferred from spent fuel bays to dry storage throughout a year because of the insufficient capacity of spent fuel pond. Safeguards inspectors verify the spent fuel transfer to meet safeguards purposes according to the safeguards criteria by means of inspector's presence during the transfer campaign. For the verification, 60-80 person-days of inspection (PDIs) are needed during approximately 3 months for each unit. In order to reduce the inspection effort and operators' burden, an Unattended Monitoring System (UMS) was designed and developed by the IAEA for the verification of spent fuel bundles transfers from wet storage to dry storage. Based ...
The Belgian Tihange 2 nuclear power plant went into commercial operation in 1983 producing a thermal power of 2785 MW. Since the commissioning of the plant the steam generators U-tubes have been affected by primary stress corrosion cracking. In order to avoid further degradation of the performance and an increase in repair costs, Electrabel, the owner of the plant, decided in 1997 to replace the 3 steam generators. This decision was supported by the feasibility study performed by Tractebel Energy Engineering which demonstrated that an increase of 10% of the initial power together with a fuel cycle length of 18 months was achieved. Tractebel Energy Engineering was entrusted by Electrabel as the owner's engineer to manage the project. This paper presents the role of Tractebel Energy Engineering in this project and the safety analysis program necessary to justify the new operation point and the fuel cycle extension to 18 months re-analysis of FSAR chapter 15 accidents and ...
The Japan Atomic Energy Research Institute has conducted a piping reliability test program to demonstrate the safety and reliability of light water reactor primary piping. In this program, pipe fatigue test, leak-before-break (LBB) verification test and pipe rupture test were carried out to examine the integrity of piping, to verify the LBB and to demonstrate the effectiveness of protective measures against jet impingement and pipe whip loads under a pipe rupture event.In the pipe fatigue test, a procedure to predict the fatigue crack growth was developed, and the integrity of piping during the plant service life was evaluated. In the LBB verification test, the pipe fracture test and the leak rate test were performed to verify the LBB in the primary piping.In the pipe rupture test, the influence of jet impingement on the target disk and the deformation behavior of whipping pipe and restraint were investigated. Using the test results, the jet ...
Upon request by the Science and Technology Agency of Japanese Government, the Japan Atomic Energy Research Institute has conducted Piping Reliability Test Program to demonstrate the safety and reliability of light water reactor primary pipings. In this report, the results of the program are summarized. In the test program, pipe fatigue tests, Leak-Before-Break (LBB) verification tests and pipe rupture tests were carried out to examine the integrity of pipings, to verify the LBB concept and to demonstrate the effectiveness of the protective measures against jet impingement and pipe whip under pipe rupture event, respectively. In the pipe fatigue tests, a procedure to predict the fatigue crack growth was developed and the integrity of piping during plant service life was demonstrated. In the LBB verification tests, pipe fracture tests and leak rate tests were performed using cracked pipes. Based on the test results, LBB in the primary pipings was ...
We describe in a comprehensive fashion the Los Alamos second-generation system for passive and active neutron assays of drum-size containers. The developmental history of this 7-year project is presented with emphasis on the pulsed active neutron technique (differential dieaway), which has achieved milligram levels of assay sensitivity for both plutonium and uranium wastes. We describe in detail the matrix effects for both passive and active neutron assays. We present in a thorough fashion our novel approach to achieving comprehensive corrections for these matrix effects using measurements made during the assays. We develop a matrix correction formalism based on separate neutron absorption and moderator indices determined from these measurements. These are presented as a series of analytic functions fitted to the data. Absolute calibrations and calibration standards are discussed, as is a practical means (pink drum measurements) of achieving routine calibration ...
This paper summarizes results of reviews on the safety, critical software performed during the licensing process for the new Wolsung units. Each of these CANDU-type nuclear power plants has two micro-computerized shutdown systems. The SDS No. 1 program is graphically programmed in such a manner that its development process does not essentially differ from the design process of the conventional analog counterpart. This approach is understandable even to a reviewer in the regulatory agency without additional training in software engineering. The confidence in the reliability of this system is strengthened by the reverse verification and increased by extensive testing such as the reliability test. Concerning SDS No. 2, the development process is significantly influenced by the {open_quotes}software cost reduction project{close_quotes} of the U.S. naval research laboratory, and is, as a whole, clear and well structured except for the modules related to the operation of ...
This paper summarizes results of reviews on the safety, critical software performed during the licensing process for the new Wolsung units. Each of these CANDU-type nuclear power plants has two micro-computerized shutdown systems. The SDS No. 1 program is graphically programmed in such a manner that its development process does not essentially differ from the design process of the conventional analog counterpart. This approach is understandable even to a reviewer in the regulatory agency without additional training in software engineering. The confidence in the reliability of this system is strengthened by the reverse verification and increased by extensive testing such as the reliability test. Concerning SDS No. 2, the development process is significantly influenced by the software cost reduction project of the U.S. naval research laboratory, and is, as a whole, clear and well structured except for the modules related to the operation of the computer itself. These ...
The Kyoto Protocol is often described as a good first step towards reducing greenhouse gas (GHG) emissions into the atmosphere. The Protocol endorses emissions trading, joint implementation including 'bubbling' between Annex 1 Parties, and a clean development mechanism that allows Annex 1 and non-Annex 1 Parties to act together to reduce emissions. However, the anticipated permit market will not function if uncertainties are not rigorously assessed and considered in any compliance process. With no reliable verification tool, it is impossible to effectively assess the different mechanisms and activities mentioned under the Protocol. Thus, it is very important to study the uncertainties underlying the Kyoto relevant GHGs, here with reference to Poland, because without the consideration of uncertainty robust verification can not occur. This paper presents information about the data used in the calculations as well as the methods ...
Verification, calibration, and validation (VCV) of Computational Fluid Dynamics (CFD) codes is an essential element of the code development process. The exact manner in which code VCV activities are planned and conducted, however, is critically important. It is suggested that the way in which code validation, in particular, is often conducted--by comparison to published experimental data obtained for other purposes--is in general difficult and unsatisfactory, and that a different approach is required. This paper describes a proposed methodology for CFD code VCV that meets the technical requirements and is philosophically consistent with code development needs. The proposed methodology stresses teamwork and cooperation between code developers and experimentalists throughout the VCV process, and takes advantage of certain synergisms between CFD and experiment. A novel approach to uncertainty analysis is described which can both distinguish between and quantify ...
The full scope simulator in Daya Bay Nuclear Power Station is imported from THOMSON-CSF company in France. It is a large facility, using digital simulation technology, that simulate the main control room of Daya Bay Nuclear Power Station with the high fidelity. It is used for training operators; system analyzing including operation procedure verification. The input output interface system of the simulator is the bridge of the information exchange between instrumentation and the computer. From the point of view of data transfer, this paper discusses the operation principle of the I/O interface system.
The U.S. Support Program to International Atomic Energy Agency (IAEA) Safeguards (USSP) was established in 1977 to transfer US technology and expertise to assist the IAEA Department of Safeguards because its limited budget and scope would not allow for R&D activities and the procurement of specialized or customized equipment. Over the years, the USSP and the Department of Safeguards have worked together continuously to develop and improve processes for requesting, selecting, and managing projects that support the Safeguards verification mission. This paper will discuss the main USSP processes for accepting and processing Safeguards requests, and managing and reporting task progress.
This report has been prepared in support of the industry effort to standardize nuclear plant designs. This document describes the Combustion Engineering, Inc. System 80+trademark Standard Design. This volume contain Chapter 18 -- Human Factors Engineering. Topics covered include: design team organization and responsibilities; design goals and design bases; design process and application to human factors engineering; functional task analysis; control room configuration; information presentation and panel layout evaluation; control and monitoring outside the main control room; and verification and validation.
The product of several advanced physical coal cleaning processes is a dry, ultrafine coal (DUC), in the order of 10 microns mean mass diameter. To utilize this fuel commercially, cost-effective, environmentally safe systems must be provided for the storage, transport, and handling of this finely divided form of fuel. The objective of the project described herein is the development of total logistics systems for DUC, including experimental verification of key features. The systems to be developed will provide for safe, economic, and environmentally protective storage and delivery of DUC for residential, commercial, and industrial uses. 20 figs.
In order to consider some procedures to prevent errors in radiotherapy based in learned lessons of accidental expositions and in accordance with information contained in international reports elaborated by International Atomic Energy Agency (IAEA) and of the data base availability by the European group Radiation Oncology Safety Information System (ROSIS) on the events, a research of the occurred errors was performed. For the evaluation of the incidents a data base based in the ROSIS and added plus a parameter was created 'type of error'. All the stored data make possible the evaluation of the 839 incidents in terms of frequency of the type of error, the process of detention, the number of reached patients and the degree of severity. Of the 50 types of found errors, the type of error more frequently was 'incorrect treatment coordinate', confirmed with the data of literature and representing 28,96 por cent of the total of the incidents. The results ...
Extensive experimental and analytical investigations of fluid flow and heat transfer in gas-cooled rod bundles have been carried out. Different bundle geometries with partially or fully roughened rod surfaces were tested in a carbon dioxide loop. An advanced and comprehensive measuring control and instrumentation are important design features of this experiment. Comprehensive thermal hydraulic subchannel analysis computer codes have been developed in order to assist fuel element design calculation for gas-cooled reactors. The experiments, codes and their verification procedure are described and the results of comparisons between measured and calculated pressure and temperature distributions are given. (orig.).
This paper has the objective of presenting the philosophy of Static Var Compensator (SVC) Control as well the necessary adjustments in the project of control system to guarantee suitable performance under different operating conditions. The verification on the performance of the SVC control has been done by Transient Network Analyzer (TNA/CEPEL) studies, commissioning tests and a factory tests. The SVC is the type of Thyristor Controlled Reactor (TCR) and Thyristor Switched Capacitor (TSC). (author) 3 refs., 12 figs.
An accelerator experiment was performed using a low-energy antiproton beam to measure antiproton detection efficiency of BESS, a balloon-borne spectrometer with a superconducting solenoid. Measured efficiencies showed good agreement with calculated ones derived from the BESS Monte Carlo simulation based on GEANT/GHEISHA. With detailed verification of the BESS simulation, the relative systematic error of detection efficiency derived from the BESS simulation has been determined to be {+-}5%, compared with the previous estimation of {+-}15% which was the dominant uncertainty for measurements of cosmic-ray antiproton flux.
A 2D matrix allows a fairly rapid verification of irradiation parameters transferred on computer processing equipment without expanding the dosimetry means to implement. Associated to 'Multicheck and Verisoft' software it will handle some of the regulatory recommendations of the A.F.S.S.A.P.S. for quality control of accelerators and ensure the traceability of testing carried out. (N.C.)
Cement-based composites are widely used in applications which demand long-term service life. One important example is in immobilization matrices for low-level radioactive and other hazardous wastes, which demands long-term retention and durability. The authors describe conductivity measurements of grouts flooded with water and in contact with a sink that consists of pure water. The conductivity measurements were designed and carried out in parallel with present quality verification methods and standard leach tests of the nuclear waste management industry. For the first time, the authors show that the method of replacing intrusive chemical analysis with conductivity measurements of the leaching samples yields equivalent results.
It is possible to produce energetic beams of radioactive nuclei, as secondary beams, from the heavy-particle compound accelerator called BEVALAC. These beams can be focused into experimental areas without significant contamination using suitable magnetic filters and proper beam-optics. Properly selected high-energy beams of radioactive nuclei (those which defay by positron emission) can provide a truly unique opportunity to evaluate the effectiveness of these beams in localizing the Bragg peak on a tumor volume - necessary in heavy-particle therapy. Preliminary data are presented here to demonstrate the possible use of these beams in radiotherapy treatment-planning verification.
The ubiquitous presence of mobile communication devices and the continuous development of mo- bile data applications, which results in high level of mobile devices' activity and exchanged data, often transparent to the user, makes privacy preservation an important feature of mobile telephony systems. We present a formal analysis of the UMTS Authentication and Key Agreement protocol, using the applied pi-calculus and the ProVerif tool. We formally verify the model with respect to privacy properties. We show a linkability attack which makes it possible, for individuals with low-cost equipment, to trace UMTS subscribers. The attack exploits information leaked by poorly designed error messages.
An experimental verification for long-term performance of a Pd-Ag permeation in ITER tritium fusion cleanup units (FCU) is needed. In addition, information is required on the influence of tritium and {sup 3}He decay on the physical and chemical properties of Pd-Ag alloys (V-1). The results of the investigations of alloys (V-1) (mechanical properties and microstructure) after long-term usage exposition in tritium are given in this report. The experimental conditions (temperature, pressure, clearance, {sup 3}He concentrations) and the previous conclusions on the V-1 alloy performance are presented. (orig.).
Conformal radiation therapy represents a considerable and attractive challenge in oncology. Its aim is mainly to improve local control by increasing the dose with an acceptable rate of complications. This work overviews the world literature on this subject. The technical and theoretical requirements are highlighted. These requirements include a precise definition of the target volume by digital imaging (essentially CT scan), but also clear view of the target volume and the organs at risk, a specific collimation of the beam, 3-D dose calculations, optimization procedures, and a rigid immobilization of the patient with verification of his position. Moreover, the clinical applications of conformal radiation therapy are reviewed and discussed. (authors). 80 refs., 1 tab.
A new band gap profile (exponential profile) for the active layer of the a-SiGe:H single junction cell has been designed and experimentally demonstrated. By computer simulations we show how bending the grading of the band gap in the i-layer contributes to the enhancement of the carrier collection, improving the fill factor and efficiency. The differences observed between experiments and simulations are studied using Rutherford Backscattering Spectrometry (RBS). The results highlight weak points during the deposition process, whose control enables us to bring together experimental and computational results.
Calibration system for spot welding robots has been developed. The purpose of this system is to reduce the misalignment of tool center point (TCP) generated when teaching data made by off-line system is input to an actual robot. After the factor of the misalignment was analyzed, the relation between a main factor and the misalignment was modeled. In addition, the model was verified on experiment. The achievement of the accuracy requirement and practical use in the site was confirmed by the result of the verification. (author)
A method of using gamma radiation to determine the density and phase distribution in two-phase flows in pipes is described. Three collimated beams of radiation that pass through a pipe cross-section at different radial positions are used. A theory and computer program used to relate the measured attenuation of these beams to a three-parameter model of the phase distribution and to the average density and void fraction are discussed. Data obtained during both static and dynamic verification experiments using Lucite inserts are presented, as well as the results of several tests done in high pressure, steam-water flows.
An accelerator beam experiment was performed using a low-energy antiproton beam to measure antiproton detection efficiency of the BESS detector. Measured and calculated efficiencies derived from the BESS Monte Carlo simulation based on GRANT/GHEISHA showed good agreement. With detailed verification of the BESS simulation, the relative systematic error of detection efficiency derived from the BESS simulation has been determined to be {+-}5%, compared with the previous estimation of {+-}15% which was the dominant uncertainty for measurements of cosmic-ray antiproton flux. (author)
A dose calculation algorithm for MLC based conformal radiotherapy is described in this paper. The algorithm is formulated by the coordinate of MLC leaves. Verification on the algorithm is made by comparing the dose distributions generated by this algorithm with that generated by a Differential Convolution Superposition algorithm for various regular and irregular fields. The results demonstrate that the present algorithm has suitable accuracy and high computational efficiency, thus it could be useful for the treatment planning process in MLC based conformal radiotherapy, where the workload for interactively or automatically designing the shapes of MLC is heavy. (authors)
This report describes the results from acoustic emission (AE) and ultrasonic monitoring of the Aespoe Pillar Stability Experiment (APSE) at SKB's Hard Rock Laboratory (HRL), Sweden. The APSE is being undertaken to demonstrate the current capability to predict spalling in a fractured rock mass using numerical modelling techniques, and to demonstrate the effect of backfill and confining pressure on the propagation of micro-cracks in rock adjacent to deposition holes within a repository. An ultrasonic acquisition system has provided acoustic emission and ultrasonic survey monitoring throughout the various phases of the experiment. Results from the entire data set are provided with this document so that they can be effectively compared to several numerical modelling studies, and to mechanical and thermal measurements conducted around the pillar volume, in an 'integrated analysis' performed by SKB staff. This document ...
Development in Instrumentation and Control (I and C) technology provides more convenience and better performance, thus, adopted in many fields. To adopt newly developed technology, nuclear industry requires rigorous V and V procedure and tests to assure reliable operation. Adoption of digital system requires verification and testing of the OS for licensing. Commercial real-time operating system (RTOS) is targeted to apply to various, unpredictable needs, which makes it difficult to verify. For this reason, simple, application-oriented realtime OS is developed for the nuclear application. In this work, we show how to verify the developed RTOS at each development lifecycle. Commercial formal tool is used in specification and verification of the system. Based on the developed model, software in C language is automatically generated. Tests are performed for two purposes; one is to identify consistency between the verified model and the generated ...
Development in Instrumentation and Control (I and C) technology provides more convenience and better performance, thus, adopted in many fields. To adopt newly developed technology, nuclear industry requires rigorous V and V procedure and tests to assure reliable operation. Adoption of digital system requires verification and testing of the OS for licensing. Commercial real-time operating system (RTOS) is targeted to apply to various, unpredictable needs, which makes it difficult to verify. For this reason, simple, application-oriented realtime OS is developed for the nuclear application. In this work, we show how to verify the developed RTOS at each development lifecycle. Commercial formal tool is used in specification and verification of the system. Based on the developed model, software in C language is automatically generated. Tests are performed for two purposes; one is to identify consistency between the verified model and the generated ...
We adapt the Jain-Taylor (2003) shear-ratio geometric lensing method to measure the dark energy equation of state, w = pv/?v and its time derivative from dark matter haloes in cosmologies with arbitrary spatial curvature. The full shear-ratio covariance matrix is calculated for lensed sources, including the intervening large-scale structure and photometric redshift errors as additional sources of noise, and a maximum likelihood method for applying the test is presented. Decomposing the lensing matter distribution into dark matter haloes we calculate the parameter covariance matrix for an arbitrary experiment. Combining with the expected results from the cosmic microwave background (CMB) we design an optimal survey for probing dark energy. This shows that a targeted survey imaging 60 of the largest clusters in a hemisphere with five-band optical photometric redshifts to a median galaxy depth of zm = 0.9 could measure w0 ? w(z = 0) to a marginal 1? error of ?w0 = ...
The present paper is concerned with the prediction method for the motions and tensions of mooring lines on slack-moored floating oceanic architectural building in coastal zone. The motions and the tensions of mooring lines were estimated by the time domain numerical simulation in the present method. The present method includes the nonlinearity of mooring system, slow varying wave drift force. The authors performed a time domain numerical simulation for motions and the tensions of mooring lines on floating barge in two component waves. Also, the results obtained by numerical simulation were compared with the experimental results. The validity of the present method was confirmed.
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.
We review an analysis of a consistent renormalization of the top and bottom quark/squark sector of the MSSM with complex parameters (cMSSM). Various renormalization schemes are defined, analyzed analytically and tested numerically in the decays Stop_2 -> Sbottom_i H^+/W^+ (i = 1,2). No scheme is found that produces numerically acceptable results over all the cMSSM parameter space, where problems occur mostly already for real parameters. Some numerical examples for Gamma(Stop_2 -> Sbottom_1 H^+) in our preferred scheme, "m_b, A_b DRbar" are shown.
The aim of the safety calculation is to quantify through numerical modelling the radiological impact (molar flow, human dose) of a potential repository for radioactive waste on the Meuse/Haute Marne site at Bure. A selection process is underway for safety scenarios and their phenomenological and numerical conceptual models upstream from the safety calculation. This involves defining and quantifying the geometric and dimensional representations of the repository for each scenario plus the physical, mathematical and numerical models that reflect its behaviour and the uncertainties associated with all the parameters required to quantify the impact. A summary will be given of these various aspects. The numerical simulations are then performed on the Alliances platform which integrates the various computer codes required for the physical representation of the system. (authors)
drical Enclosures Using a Numerical Ray Tracing Technique. NASA. TM-I02527, 1990 . Buckley, H.: Radiation from the Interior of a Reflecting Cylinder. Philos. ...
The ras oncogenes function by indirectly controlling expression of a subset of yet-undefined genes that are crucial for cell growth and differentiation. In a differential display strategy, numerous...Full Text Available
This bibliography lists unclassified publications of work done at the Los Alamos National Laboratory for 1988. The entries, which are subdivided by broad subject categories, are cross-referenced with an author index and a numeric index.
terms of 11) numerical models, 2D SPH simulations, and analytic models. The 1D model was useful for determining the evolution over very long timescales. ...
Brush fires, especially during the summer months, are hazards that occasionally threaten the leeward (Waianae) coast of Oahu in Hawaii. The prediction of future ... ...
SummaryA meshless numerical model is proposed to investigate shallow-water dam break flows in 1D open channels. The numerical model is to solve the shallow water equations (SWE) based on smoothed particle hydrodynamics (SPH). The concept of slice water particles (SWP) is adopted in the SPH-SWE formulation. The numerical sensitivity analysis is first performed to study the appropriate SWP number and variable smoothing length through dam break flows in an idealized 1D channel with dry/wet beds. Extensive validation by comparison with laboratory and field data is next conducted for four benchmark problems, including dam break flows through a rough flat channel, a rough bumpy channel with various downstream boundary conditions, a nonprismatic channel, and a realistic scale model of the Toce ri...
A numerical analysis method for melting/solidification phenomena has been developed to evaluate a feasibility of several candidate techniques in the nuclear fuel cycle. Our method is based on the eXtended Finite Element Method (X-FEM) which has been used for moving boundary problems. Key technique of the X-FEM is to incorporate signed distance function into finite element interpolation to represent a discontinuous gradient of the temperature at a moving solid-liquid interface. Construction of the finite element equation, the technique of quadrature and the method to solve the equation are reported here. The numerical solutions of the one-dimensional Stefan problem, solidification in a two-dimensional square corner and melting of pure gallium are compared to the exact solutions or to the experimental data. Through these analyses, validity of the newly developed numerical analysis method has been demonstrated. (author)
... that range from relatively low frequency strong ground motion modeling [Vidale et al., 1985] to high frequency reverse time migration of seismic ...
... being pulled out of water, the movement is restricted ... This heating depended on the particle size ... hydrometeor injection into the upper tropopause. ...
The quest to understand why we age has given rise to numerous lines of investigation that have gradually converged to include metabolic control by mitochondrial activity as a major player. That...Full Text Available
Numerous reports of chronic renal disease in patients who habitually use phenacetin-containing compounds to excess have aroused considerable controversy over the possible relationship between phenacetin,...Full Text Available
... these features and yields results which are two orders of magnitude faster than those available using conventional numerical ray tracing techniques ...
ground strike hazards 3) Advancements in the initialization of numerical weather prediction models through better identification of deep convection 4) Improved routing of...
We develop and investigate numerically a thermodynamically consistent model of two-dimensional multicomponent vesicles in an incompressible viscous fluid. The model is derived using an energy...Full Text Available
Numerous bacteria from a salt-marsh environment are capable of degrading malathion, an organophosphate insecticide, when supplied with additional nutrients as energy and carbon sources. Seven isolates...Full Text Available
Jan 7, 2010 ... Deforestation. The environmental implications of the word are as numerous as the syllables. And scientists like Jim Collatz have the job of ...
(Lactuca scariole),morning glory (Ipomea sp.), broomsedge (Andropogon virginicus ) and numerous composites. Because this area is leveed -and managed it ...
It is shown numerically that on a time scale of order 1 msec a neutron star with pion condensation will undergo separation into a core and an envelope with a sharp interface. The envelope will not, however, be ejected.
Carboxylesterases (CE) are ubiquitous enzymes that hydrolyze numerous ester-containing xenobiotics, including complex molecules, such as the anticancer drugs irinotecan (CPT-11) and capecitabine...Full Text Available
BackgroundMany commercial banana varieties lack sources of resistance to pests and diseases, as a consequence of sterility and narrow genetic background. Fertile wild relatives,...Full Text Available
I summarize the extant direct and indirect data on the sky background SNAP will see at the North Ecliptic Pole over the wavelength range 0.4 < {lambda} < 1.7 {micro}m. At the spatial resolution of SNAP the sky background due to stars and galaxies is resolved, so the only source considered is zodiacal light. Several models are explored to provide interpolation in wavelength between the broadband data from HST and COBE observations. I believe the input data are now established well enough that the accuracy of the sky background presented here is sufficient for SNAP simulations, and that it will stand up to scrutiny by reviewers.
Before working at JPL he was the Chief Engineer for the Milstar Satellite Avionics and several Military space programs. His technical background is in ...
LUCIFER (Low-background Underground Cryogenic Installation For Elusive Rates) is a new project for the study of neutrinoless Double Beta Decay, based on the technology of scintillating bolometers. These devices promise a very efficient rejection of the alpha background, opening the way to a virtual background-free experiment if candidates with a transition energy higher than 2615 keV are investigated. The baseline candidate for LUCIFER is 82Se. This isotope will be embedded in ZnSe crystals grown with enriched selenium and operated as scintillating bolometers in a low-radioactivity underground dilution refrigerator. In this paper, the LUCIFER concept will be introduced. The sensitivity and the very promising prospects related to this project will be discussed.
Continuum events represent an eminent source of background in any e+e- experiment. As these have a higher branching ratio than BB-bar events (at BaBar this ratio is estimated to about 3.5) or ?+?- events, efficient continuum background suppression is essential in many analyses. Using Artificial Neural Networks and the Nearest Neighbor Method we developed several selectors which, based only on the global event shape variables, efficiently tag BB-bar events and ?+?- events against the continuum background. These selectors could then be combined with the channel specific information in various types of analyses. The study was done using a parametric Monte Carlo.
We entertain the idea that a suitable background of cold (very low momentum) pseudoscalar particles or condensate, may trigger a background that effectively generates Lorentz-invariance violation. This aether-like background induces a Chern-Simons modification of QED. Physics is different in different frames and, in the rest frame of the pseudoscalar background, high momentum photons can decay into pairs. The threshold for such decay depends quadratically on the rest mass of the particles. This mechanism could explain in a natural way why antiprotons are absent in recent cosmic ray measurements. A similar signal could be used as a probe of pseudoscalar condensation in heavy ion collisions.
Properties of the multi-species electromagnetic Weibel and electrostatic two-stream instabilities are investigated for an intense ion beam propagating through background plasma. Assuming that the background plasma electrons provide complete charge and current neutralization, detailed linear stability properties are calculated within the framework of a macroscopic cold-fluid model for a wide range of system parameters.
...this page document analysis carried out during the policy development of the CRC Energy Efficiency Scheme. policy, background, carbon, reduction,...commitment, energy efficiency, CRC, Policy background Spending Review Announcement In the October 2010 Spending Review, the UK Government announced that the CRC ... Revenue from the sale of CRC allowances, totalling ٟ billion a year by 2014/15, will be used to support ... The implications of this announcement for CRC are: In order to clarify the price signal to participants and to support the public ...
Numerical results on aeroelastic standard configurations are presented. The methods used for two dimensional configurations include the small perturbations approach for inviscid flow, coupling methods for unseparated flow, coupling methods for unseparated or separated, laminar or turbulent boundary layers, and a numerical solution of the Euler equations for inviscid flow. The three dimensional configurations are studied by the transonic small disturbance approach. The detailed results are given.
Parameters of the vortex air flow in an isothermal model of the cyclone chamber are studied. The effect of the air velocity in nozzles on the values and character of the distribution of pressure and tangential and longitudinal velocities of air in the chamber is determined. Numerical modeling of the flow is performed, and it is shown that numerical calculation by the k-w turbulence model is in agreement with experimental data.
The structure of polydispersed populations of unilamellar vesicles is studied by small-angle neutron scattering for three types of lipid systems, namely, single-, two-and four-component vesicular systems. Results of the numerical analysis based on the separated-form-factor model are reported.
In this paper the stress due to torsion and the torsional buckling behavior of bellows are investigated through both theoretical and numerical analyses. The numerical solutions agree with the theoretical results very well in a wide range of dimensions and the number of convolutions. Based on these results, the framework of the design rule related to the torsion of bellows is proposed. (J.P.N.).
We study by means of Quantum Monte Carlo simulations based on the Worm Algorithm the low temperature (down to T = 0.05 K) properties of parahydrogen clusters comprising up to 40 molecules. Three different intermolecular interactions are employed: the Silvera-Goldman, the Buck and the Lennard-Jones potential. Despite important discrepancies observed in the numerical estimates of energy and superfluid fraction, the mechanism by which clusters melt at low T is independent of the particular choice of the potential, whose only effect is to alter the temperature scale.
Results are given of numerical simulation of three-dimensional pattern of flow of a two-phase steam-water mixture in the house of a PGV-1000 horizontal steam generator obtained using the BAGIRA best-estimate thermohydrodynamic computer codes. The space distributions of velocities and local void fractions in the steam generator housing for different modes of operation of power-generating unit are calculated and compared with available experimental data.
Results are given of numerical simulation of three-dimensional pattern of flow of a two-phase steam-water mixture in the house of a PGV-1000 horizontal steam generator obtained using the BAGIRA best-estimate thermohydrodynamic computer codes. The space distributions of velocities and local void fractions in the steam generator housing for different modes of operation of power-generating unit are calculated and compared with available experimental data.
Numerical errors of PALLAS calculation due to spatial mesh sizes are examined for a typical deep penetration shielding problem of isotropic incident fission neutrons penetrating a 200-cm-thick water slab. The exponential approximation for the source spatial distribution to solve the transport equation based on the direct integration method is verified to be effective for radiation transport in attenuating medium, while the linear approximation employed in the old PALLAS code is found to produce large errors for calculations with large mesh sizes.
A numerical calculation procedure applicable to cavity-type receiver configurations and flow conditions was developed. Flow visualization experiments were performed, and experimental measurements of quantities valuable for the development of the numerical calculation procedure were made. The investigation is focussed on a configuration which is strongly two-dimensional in the mean flow structure (but turbulent in a truly three-dimensional sense). (LEW)
Tthe acceleration of a liquid from a cylindrical container by the products of instantaneous detonation of a superimposed explosive charge (implosion method) is studies numerically in a two-dimensional formulation. Analytical formulas for the asymptotic velocities of liquid expansion and acceleration of the container body were obtained using numerical calculations in a one-dimensional approximation. The effect of the fracture of the body on the velocity of liquid expansion was studied in a two-dimensional formulation.
Collisional-Radiative numerical models are commonly used to design or interpret experiments in atomic physics of laser-created plasmas, including X-ray laser studies. We describe our new code containing several options: average ion, more or less detailed configurations. It consists of an atomic data base coupled to subroutines evaluating ionic populations and emission and absorption coefficients. Numerical results are given to illustrate the capabilities of the code and to compare different models and types of approximation.
A three-dimensional numerical simulation of mammatus-like clouds is presented. A portion of a cirrus outflow anvil cloud is simulated including cloud ice and snow microphysical representations. The simulated mammatus clouds appear in a cellular pattern and are compared with the few available previously published physical observations of mammatus. Copyright Copyright 2006 Royal Meteorological Society
In this paper, finite-difference time-domain method is used to research the transient electromagnetic pulse (EMP) coupling to the cylinder object which is shielded in another shielding cavity with a hole numerically. The different coupling effectiveness of three transient EMP is simulated. The distribution of the electric field in the shielding cavity and the current on the cavity are researched. The shielding effectiveness is evaluated. (authors)
The existence of a cosmic neutrino background - the analogue of the cosmic microwave background - is a fundamental prediction of standard big bang cosmology. Up to now, the observational evidence for its existence is rather indirect and rests entirely on cosmological observations of, e.g., the light elemental abundances, the anisotropies in the cosmic microwave background, and the large scale distribution of matter. Here, we review more direct, weak interaction based detection techniques for the cosmic neutrino background in the present epoch and in our local neighbourhood. We show that, with current technology, all proposals are still off by some orders of magnitude in sensitivity to lead to a guaranteed detection of the relic neutrinos. The most promising laboratory search, based on neutrino capture on beta decaying nuclei, may be done in future experiments designed to measure the neutrino mass ...
A three-dimensional numerical simulation of the loss-of-feed water transient at the horizontal steam generator of the Kola nuclear power plant is performed. Presented numerical results show transient change of integral steam generator parameters, such as steam generation rate, water mass inventory, outlet reactor coolant temperature, as well as detailed distribution of shell side thermal-hydraulic parameters: swell and collapsed levels, void fraction distributions, mass flux vectors, etc. Numerical results are compared with measurements at the Kola NPP. The agreement is satisfactory, while differences are close to or below the measurement uncertainties. Obtained numerical results are the first ones that give complete insight into the three-dimensional and transient horizontal steam generator thermal-hydraulics. Also, the presented results serve as benchmark tests for the assessment and further ...
Finite-difference acoustic-wave modeling and reverse-time depth migration based on the full wave equation are general approaches that can take into account arbitrary variations in velocity and density and can handle turning waves as well. However, conventional finite-difference methods for solving the acoustic- or elastic-wave equation suffer from numerical dispersion when too few samples per wavelength are used. The flux-corrected transport (FCT) algorithm, adapted from hydrodynamics, reduces the numerical dispersion in finite-difference wavefield continuation. The flux-correction procedure endeavors to incorporate diffusion into the wavefield continuation process only where needed to suppress the numerical dispersion. Incorporating the flux-correction procedure in conventional finite-difference modeling or reverse-time migration can provide finite-difference solutions with no numerical dispersion even ...
WIPS (Whip and Impact of Piping Systems) is a special purpose computer code for the structural analysis of pipe whip dynamic effects following a postulated pipe rupture. WIPS has been developed primarily to provide support for the pipe whip analysis procedures described in Section 3.6.2 of the US Nuclear Regulatory Commission Standard Review Plan. This report summarizes the purpose and scope of the WIPS development effort, identifying those clauses in the Standard Review Plan which refer to pipe whip analysis, and indicating how the WIPS code can be used to provide supporting data. Detailed information on use of the code is contained in accompanying reports which cover: (1) user instructions; (2) theory; (3) programming procedures; and (4) verification examples.
Inductive electromagnetic launchers, or coilguns, use discrete solenoidal coils to accelerate a coaxial conductive armature. To date, Sandia has been using an internally developed code, SLINGSHOT, as a point-mass lumped circuit element simulation tool for modeling coilgun behavior for design and verification purposes. This code has shortcomings in terms of accurately modeling gun performance under stressful electromagnetic propulsion environments. To correct for these limitations, it was decided to attempt to closely couple two Sandia simulation codes, Xyce and ALEGRA, to develop a more rigorous simulation capability for demanding launch applications. This report summarizes the modifications made to each respective code and the path forward to completing interfacing between them.
The Authenticated Tracking and Monitoring System (ATMS) has been designed to address the need for global monitoring of the status and location of proliferation-sensitive items. Conceived to utilize the proposed Global Verification and Location System (GVLS) satellite link, ATMS could use the existing International Maritime Satellite commercial communication system until GVLS is operational. The ATMS concept uses sensor packs to monitor items and environmental conditions, collects a variety of events data through a sensor processing unit, and transmits the data to a satellite, which then sends data to ground stations. Authentication and encryption algorithms will be used to secure the data. A typical ATMS application would be to track and monitor the safety and security of a number of items in transit along a scheduled shipping route. This paper also discusses a possible proof-of-concept system demonstration.
In this study the results of mathematical simulation and experimental research of texture transition in stress assisted shear phase transformations are discussed. The orientation distribution function (ODF) calculation model to the any type crystalline lattice symmetry materials has been suggested. By crystalline lattice symmetry analysis this computer program determines necessary amount of the initial experimental data. The experimental verification supports this model well. The ODF calculation model after shear phase transformation with equal use of all possible variants of orientation relationship or with various degrees of variant selection worked out. In this study the experimental and calculating data of the direct and reversal shear transformations #alpha# <=> #gamma# in Fe-alloys and B2 <=> B19' in Ti-Ni alloys are discussed. The stress assisted shear phase transformation model and computer program to calculate ODF after transformation have been ...
A brief FFTF project description is provided which includes general plant siting information, general layout, plant design parameters, description of principal systems and components, and description of support facilities. The current status of the FFTF project is provided, including status of plant construction, overall status of the plant checkout and test program, status of operating authorization and plant operating procedures and personnel, and status of reactor core components and experiments. Specific information on the acceptance test program and early program results is discussed. The role of FFTF in the future breeder program is described, including its objectives for verification of plant system and components designs and operability and use as an irradiation test facility.
Planning is an important part of computational model verification and validation (V&V) and the requisite planning document is vital for effectively executing the plan. The document provides a means of communicating intent to the typically large group of people, from program management to analysts to test engineers, who must work together to complete the validation activities. This report provides guidelines for writing a validation plan. It describes the components of such a plan and includes important references and resources. While the initial target audience is the DART Full System Model teams in the nuclear weapons program, the guidelines are generally applicable to other modeling efforts. Our goal in writing this document is to provide a framework for consistency in validation plans across weapon systems, different types of models, and different scenarios. Specific details contained in any given validation plan will vary according to application ...
RESRAD was one of the multimedia models selected by the US Nuclear Regulatory Commission (NRC) to include in its workshop on radiation dose modeling and demonstration of compliance with the radiological criteria for license termination. This paper is a summary of the presentation made at the workshop and focuses on the 10 questions the NRC distributed to all participants prior to the workshop. The code selection criteria, which were solicited by the NRC, for demonstrating compliance with the license termination rule are also included. Among the RESRAD family of codes, RESRAD and RESRAD-BUILD are designed for evaluating radiological contamination in soils and in buildings. Many documents have been published to support the use of these codes. This paper focuses on these two codes. The pathways considered, the databases and parameters used, quality control and quality assurance, benchmarking, verification and validation of these codes, and capabilities as well as ...
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 presented.
Production engineering measures for improving production techniques to increase the reliability of high voltage, high temperature aluminum electrolytic capacitors have been completed. The required number of capacitors for each contract item were life tested at 85C for 10,000 hours. There were 9,400 capacitors on the extended life test. Reliability for CU13 and CU17 capacitors and contract item 2AG rated 1.5 mfd - 400 V are shown. The verification testing, which was performed at 125 C on 40 capacitors for each contract item, met the requirements of MIL-C-39018A. It further demonstrated that in addition to CU13 styles which are designed to operate at 125 C, the CU17 manufactured for this contract are capable of operating at 125C with derated voltage. Process specifications and Quality Control Manual are included.
Portal localization images for high-energy electron beam therapy are necessary to confirm the treatment field by comparing them with a simulation image obtained before treatment or portal verification images after treatment. In this study, portal localization images were acquired using the computed radiography (CR) system and bremsstrahlung X-rays generated in the electron beam irradiations. All images obtained with phantom and the irradiations of in the electron energy of 8, 10, 12 and 15 MeV were feasible for clinical use. The CR system used in this study included general diagnostic imaging cassette and storage phosphor plate, but none of other special devices. The system can usually supply portal localization images, which maintains the quality assurance of high-energy electron beam therapy. (author)
This issue of Carbon Market Perspectives on 'Pathways for implementing REDD+: Experience from carbon markets and communities' discusses the role of carbon markets in scaling up investments for REDD+ in developing countries. Nine articles authored by experienced negotiators on REDD+, carbon market actors, project developers and other leading experts share experiences and make suggestions on the key elements of a future international REDD+ regime: Architecture and underlying principles, measuring, reporting and verification (MRV), private-sector involvement, the rights of indigenous people and local communities, biodiversity conservation and environmental integrity. The articles are grouped under three main topics: the lessons of existing REDD+ projects; the future REDD+ regime and the role of carbon markets; and experiences and ideas about the involvement of indigenous people and local communities. (LN)
The prospects for the low-aspect-ratio (A) tokamak to fulfill the requirements of viable fusion power plants are considered relative to the present status in data and modeling. Desirable physics and design features for an attractive Blanket Test Facility and power reactors are estimated for low-A tokamaks based on calculations improved with the latest data from small pioneering experiments. While these experiments have confirmed some of the recent predictions for low-A, they also identify the remaining issues that require verification before reliable projections can be made for these deuterium-tritium applications. The results show that the low-A regime of small size, modest field, and high current offers a path complementary to the standard and high A tokamaks in developing the full potential of fusion power.
A method has been developed to optimize the energy resolution of a horizontally focusing monochromator. The method consists of determining the optimum radius of curvature of the cylindrically bent monochromator crystal by minimizing the total diffracted X-ray flux measured through an X-ray absorption foil. When measured at an absorption edge a global minimum can be identified, which corresponds to the minimum energy band accepted along the entire length of the crystal. Experimental verification of this method has been validated by comparing X-ray fluorescent scans taken for a series of crystal curvatures and by directly measuring the X-ray beam profiles at the corresponding points. The actual optical configuration and asymmetric-cut parameter of the focusing monochromator on beamline X4C at the National Synchrotron Light Source are modeled and ray tracing simulations of the optical system are compared with direct beam profile measurements.
Due to size and costs of big slewing rings, the common methods of experimental trial and error together with destructive test methods for verification of the inductive hardening process are limited. Thereby it is essential to simulate the hardening process in addition to the tests. With these simulations, it should be possible to get conclusions for the hardening pattern, the residual stress and distortion. With actually existing methods a fully three dimensional simulation is extremely time consuming. For that reason, a new method was developed that combines two dimensional with three dimensional simulation to shorten the time for calculation tremendously. (orig.)
A 500 keV negative-ion based NBI system is under construction for NB current drive and plasma core heating in high density plasma in JT-60U. Part of the beamline and the high voltage power supply required for a verification test of an ion source was completed in March 1995. After having done a high potential test of the power supply, the negative-ion generation and acceleration tests started in June 1995 aiming at deuterium beams of 500 keV, 22A. In initial experiment, deuterium negative-ion beams of 410 keV, 6.1A (2.5 MW) for 0.2 sec, so far, have been achieved. This is the world highest D{sup {minus}} current and negative ion beam power. The construction of the total system will be completed by the beginning of 1996, and the beam injection will start in March 1996.
Monte Carlo neutron transport methods can be used to verify the applicability of point kinetics for safety analysis of nuclear reactors. KENO-NR was used to obtain the transfer function of the Advanced Neutron Source reactor and the time delay between the core power production and the external detectors, a parameter of interest to the safety systems design. The good agreement between the Monte Carlo generated transfer function and the point kinetics transfer function validates that the uncommon ANS geometry does not preclude the use of point kinetics in the frequency range that was investigated. Various features of the power spectral densities also demonstrated the applicability of point kinetics. The time delay was obtained from the cross-power spectral density (CPSD) and is {approximately}15 ms. These analyses show that frequency analysis can be used experimentally to investigate the validity of the use of point kinetics models in critical experiments or zero power testing of ...
This thesis deals with the reduced-order modeling of electrical machines and interconnected power systems in the medium time scale using integral manifold techniques. First, an improved model for power system stabilizer design that captures the damping due to the amortisseur windings while retaining the simplicity of the DeMello-Concordia model is presented. Second, time scales of the regulated synchronous machine are analyzed using the linearized models, and the well-known effects of the high-gain regulator on the system are explained. A reduced-order model that captures the damping due to the power-system stabilizer is presented. Third, speed-damping terms are obtained in the swing equation in a multimachine environment by approximating the integral manifold associated with fast damper windings. This provides a theoretical basis for the practice of adding cross-damping terms to the swing equation to account for damping present in the system. Verification for the ...
Protein motions on all timescales faster than molecular tumbling are encoded in the spectral density. The dissection of complex protein dynamics is typically performed using relaxation rates determined at high and ultra-high field. Here we expand this range of the spectral density to low fields through field cycling using the nucleocapsid protein of the SARS coronavirus as a model system. The field-cycling approach enables site-specific measurements of R{sub 1} at low fields with the sensitivity and resolution of a high-field magnet. These data, together with high-field relaxation and heteronuclear NOE, provide evidence for correlated rigid-body motions of the entire {beta}-hairpin, and corresponding motions of adjacent loops with a time constant of 0.8 ns (mesodynamics). MD simulations substantiate these findings and provide direct verification of the time scale and collective nature of these motions.
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.
This engineering report compiles information on types and quantities of liquid waste discharged from B-Plant directly to cribs, ditches, reverse wells, etc., that are associated with B-Plant. Waste discharges to these cribs via overflow form 241-B, 241-BX, and 241-BY tank farms, and waste discharged to these cribs from sources other than B-Plant are discussed.Discharges from B-Plant to other cribs, unplanned releases, or waste remaining in tanks are not included in the report. Waste stream composition information is used to predict quantities of individual chemicals sent to cribs. This provides an accurate mass balance of waste streams from B-Plant to these cribs. These predictions are compared with known crib inventories as a verification of the process.
This research aims to develop reliable, advanced system thermal-hydraulic computer code and to quantify the uncertainties of code to introduce the best estimate methodology of ECCS for LBLOCA. Although the one of best estimate code, RELAP5/MOD3.1 was introduced from USNRC, several deficiencies in its reflood model and some improvements have been made. The improvements consist of modification of reflood wall heat transfer package and adjusting the drop size in dispersed flow regime. The tome smoothing of wall vaporization and level tracking model are also added to eliminate the pressure spike and level oscillation. For the verification of improved model and quantification of associated uncertainty, the FLECHT-SEASET data were used and upper limit of uncertainty at 95% confidence level is evaluated. (Author) 30 refs., 49 figs., 2 tabs.
Pork identification in four types of food products, which are sausages and the casings, bread and biscuits, using species-specific polymerase chain reaction (PCR) detection of a conserved region in the mitochondrial (mt) 12S ribosomal RNA (rRNA) gene was developed. Genomic DNA of the food products were successfully extracted except for the casing samples, where no genomic DNA was detected. The extracted genomic DNA was then subjected to PCR amplification targeting the specific regions of the 12S rRNA gene. The genomic DNA from the food products were found to be of good quality and produced clear PCR products on the amplification of 12S rRNA gene of 387 base pairs (bp) from pork species. The species-specific PCR identification yielded excellent results for identification of pork derivatives...
The present Manual provides guidance and illustrative examples for applying a method by which graded quality assurance requirements may be determined and adapted to the items and services of a nuclear power plant in conformance with the requirements of the IAEA Nuclear Safety Standards (NUSS) Code and Safety Guides on quality assurance. The Manual replaces the previous publication IAEA-TECDOC-303 on the same subject. Various methods of grading quality assurance are available in a number of Member States. During the development of the present Manual it was not considered practical to attempt to resolve the differences between those methods and it was preferred to identify and benefit from the good practices available in all the methods. The method presented in this Manual deals with the aspects of management, documentation, control, verification and administration which affect quality. 1 fig., 4 tabs.
RELAP5/MOD3 code was developed for western type power water reactors with vertical steam generators. Thus, this code should be validated also for VVER design with horizontal steam generators. The validation work, which has been started in Lappeenranta University of Technology (LUT), has already shown some weaknesses of the code. For example the flow inside a steam generator horizontal tube in some accident cases is not correctly modelled by the code. It may be the result of erroneous prediction of the flow regime. The aim of the study is the attempt of verification of the flow regime map, which is used in the RELAP5/MOD3 computer code for two-phase flow in horizontal tubes. (18 refs.).
A brief summary of the theory and experiments on electron- cyclotron heating and current drive is presented. The general relativistic formulation of wave propagation and linear absorption is considered in some detail. The O-mode and the X-mode for normal and oblique propagation are investigated and illustrated by several examples. The experimental verification of the theory in T-10 and D- III-D is briefly discussed. Quasilinear evolution of the momentum distribution and related applications as, for instance, non linear wave, damping and current drive, are also considered for special cases of wave frequencies, polarization and propagation. In the concluding section we present the general formulation of the wave damping and current drive in the absence of electron trapping for arbitrary values of the wave frequency. (Author) 13 refs.
SAMPSON is an integration of twelve analysis modules under the final development phase (phase-2) and will be capable of simulating hypothesized severe accidents in a nuclear power plant. One of these modules, the Molten Core Relocation Analysis (MCRA) module, simulates the relocation behavior of a molten core during a severe accident. MCRA models severe accident phenomena by using mechanistic formulations for multi-phase, multi-component, and multi-velocity field. As one of the verification studies of SAMPSON in Phase-1, the in-core phenomena of PHEBUS/FPT0 was analyzed with three modules, MCRA, fuel rod heat up analysis (FRHA) module, and the analysis control module (ACM) of SAMPSON. (author)
A non-contact method, using magnetic drag force principle, was proposed to design the braking systems to improve the shortcomings of the conventional braking systems. The extensive literature detailing all aspects of the magnetic braking is briefly reviewed, however little of this refers specifically to upright magnetic braking system, which is useful for industries. One of the major issues to design upright magnetic system is to find out the magnetic flux. The changing magnetic flux induces eddy currents in the conductor. These currents dissipate energy in the conductor and generate drag force to slow down the motion. Therefore, a finite element model is developed to analyze the phenomena of magnetic flux density when air gap and materials of track are varied. The verification shows the predicted magnetic flux is within acceptable range with the measured value. The results will facilitate the design of magnetic braking systems.
The Commissariat a l'Energie Atomique (CEA, French Atomic Energy Commission) has set up over the last 10 years an innovative methodology aiming at characterizing radiological contaminations. The application of the latter relies on various tools such as expertise vehicles with impressive detection performances (VEgAS) and recently developed software platform called Kartotrak. A Geographic Information System tailored to radiological needs constitutes the heart of the platform; it is surrounded by several modules aiming at sampling optimization (Stratege), data analysis and geostatistical modeling (Krigeo), real-time monitoring (Kartotrak- RT) and validation of cleaning efficiency (Pescar). This paper presents the different tools which provide exhaustive instruments for the follow-up of decontamination projects, from doubt removal to the verification of the decontamination process. (authors)
Sandia National Laboratories has the qualification evaluation responsibility for the design of certain components intended for use in nuclear weapons. Specific techniques in assurance and assessment have been developed to provide the quality evidence that the software has been properly qualified for use. Qualification Evaluation is a process for assessing the suitability of either a process used to develop or manufacture the product, or the product itself The qualification process uses a team approach to evaluating a product or process, chaired by a Quality Assurance professional, with other members representing the design organization, the systems organization, and the production agency. Suitable for use implies that adequate and appropriate definition and documentation has been produced and formally released, adequate verification and validation activities have taken place to ensure proper operation, and the software product meets all requirements, explicitly or ...
The Atmospheric Release Advisory Capability (ARAC) at the Lawrence Livermore National Laboratory uses the U.S. Navy's Coupled Ocean/Atmosphere Mesoscale Prediction System (COAMPS) to supply high-resolution wind data for use in its real-time dispersion modeling system. ARAC has used COAMPS products to support several events and exercises, and COAMPS forecasts appear accurate, based on qualitative examination. Recently ARAC has developed a quantitative verification system which calculates COAMPS error and bias statistics, comparing COAMPS forecasts of various lengths with observational data. This paper shows how this system has been used to guide ARAC operators, who need an estimate of the likely behavior of COAMPS forecasts of various lengths in different regions, seasons, and weather patterns.
With the rapid growth of Information and Communication Technology, Electronic commerce is now acting as a new means of carrying out business transactions through electronic means such as Internet environment. To avoid the complexities associated with the digital cash and electronic cash, consumers and vendors are looking for credit card payments on the Internet as one possible time-tested alternative. This gave rise of the on-line payment processing using a third-party verification; which is not suitable for the developing countries in most of the cases because of the excessive costs associated with it for maintenance and establishment of an online third-party processor. As a remedy of this problem, in this paper, we have proposed a framework for easy security incorporation in credit card based electronic payment system without the use of an on-line third- party processor; which tends to be low cost and effective for the developing countries.
A fundamental Doppler-like but asymmetric wave effect that shifts received signals in frequency in proportion to their respective source distances, was recently described as means for a whole new generation of communication technology using angle and distance, potentially replacing TDM, FDM or CDMA, for multiplexing. It is equivalent to wave packet compression by scaling of time at the receiver, converting path-dependent phase into distance-dependent shifts, and can multiply the capacity of physical channels. The effect was hitherto unsuspected in physics, appears to be responsible for both the cosmological acceleration and the Pioneer 10/11 anomaly, and is exhibited in audio data. This paper discusses how it may be exploited for instant, passive ranging of signal sources, for verification, rescue and navigation; incoherent aperture synthesis for smaller, yet more accurate radars; universal immunity to jamming or interference; and precision frequency scaling of ...
The subject of Tachyons, even if still speculative, may deserve some attention for reasons that can be divided into a few categories, two of which are as follows: The larger scheme, to build up in order to incorporate space-like objects in the relativistic theories. These allow better understanding of many aspects of the ordinary relativistic physics, even if Tachyons would not exist in our cosmos as ''asymptotically free'' objects; superliminal classical objects can have a role in elementary particle interactions (perhaps even in astrophysics) and possible verification of the reproduction of quantum-like behaviour at a classical level when taking into account the possible existence of faster-than-light classical particles. This paper shows that Special Relativity - even without tachyons - can be given a form which describes both particles and anti-particles. This paper also is confined only to a ''model theory'' of Tachyons in two dimensions.
The research documented herein was funded by a research contract between the Research Reactors Division (RRD) of Oak Ridge National Laboratory (ORNL) and the University of Tennessee, Knoxville (UTK) Mechanical, Aerospace and Biomedical Engineering Department (MABE). The research was governed by a statement of work (SOW) which clearly defines nine specific tasks. This report is outlined to follow and document the results of each of these nine specific tasks. The primary goal of this phase of the research is to demonstrate, through verification and validation methods, that COMSOL is a viable simulation tool for thermal-hydraulic modeling of the High Flux Isotope Reactor (HFIR) core. A secondary goal of this two-dimensional phase of the research is to establish methodology and data base libraries that are also needed in the full three-dimensional COMSOL simulation to follow. COMSOL version 3.5a was used for all of the models presented throughout this report.
Complete calculations of the accelerator related background in the muon spectrometer of the CMS detector at the Large Hadron Collider are presented. The simulations have been performed with the STRUCT multi-turn tracking code and the MARS and FLUKA cascade codes taking into account latest information of the LHC lattice, vacuum conditions, beam cleaning system and the shielding and layout of the CMS experiment. Beam loss distributions in the interaction regions and their vicinities and their contribution to the background levels in the muon spectrometer of CMS are analyzed. The studies show that hadronic and electromagnetic components of machine background are efficiently suppressed by the proposed CMS shielding. High energy muons penetrate through the shielding, but in positions of significance they do not contribute more than a few percent compared to the background generated by the pp-collisions. It ...
NO{sub x} compounds, specifically NO and NO{sub 2}, are pollutants and potent greenhouse gases. Compact and inexpensive NO{sub x} sensors are necessary in the next generation of diesel (CIDI) automobiles to meet government emission requirements and enable the more rapid introduction of more efficient, higher fuel economy CIDI vehicles. Because the need for a NO{sub x} sensor is recent and the performance requirements are extremely challenging, most are still in the development phase. Currently, there is only one type of NO{sub x} sensor that is sold commercially, and it seems unlikely to meet more stringent future emission requirements. Automotive exhaust sensor development has focused on solid-state electrochemical technology, which has proven to be robust for in-situ operation in harsh, high-temperature environments (e.g., the oxygen stoichiometric sensor). Solid-state sensors typically rely on yttria-stabilized zirconia (YSZ) as the oxygen-ion conducting electrolyte and then target ...
Since information has been regarded os a physical entity, the field of quantum information theory has blossomed. This brings novel applications, such as quantum computation. This field has attracted the attention of numerous researchers with backgrounds ranging from computer science, mathematics and engineering, to the physical sciences. Thus, we now have an interdisciplinary field where great efforts are being made in order to build devices that should allow for the processing of information at a quantum level, and also in the understanding of the complex structure of some physical processes at a more basic level. This thesis is devoted to the theoretical study of structures at the nanometer-scale, 'nanostructures', through physical processes that mainly involve the solid-state and quantum optics, in order to propose reliable schemes for the processing of quantum information. Initially, the main results of quantum information ...
The verification test program on zinc injection applicability to Japanese BWRs was started in 1997. Laboratory tests using high temperature water loops under BWR reactor water conditions are in progress. This paper is an interim report on results obtained so far. Co-58 and Zn-65 were simultaneously used in the Co radioactivity buildup test to evaluate zinc injection suppression effects towards cobalt deposition on pre-oxidized stainless steel. The following results were obtained. The Co deposition was suppressed effectively by Zn injection, even when there was a pre-oxide film. For the test piping that had the pre-oxide film formed under the NWC (normal water chemistry) condition, when soaked under the HWC (hydrogen water chemistry) condition a large amount of Co-58 was taken into a small part of the inner layer. The distribution ratio of Co-58 in the inner layer and outer layer of the oxide film was almost the same for both the pre-oxidized test piping and the non ...
The IAEA Code of Practice on Quality Assurance for Safety in Nuclear Power Plants and the corresponding Safety Guides are reviewed and compared with quality assurance (QA) practices in the IAEA Member States. The QA requirements stipulated by the Code place on the nuclear power plant owner the responsibility to establish an overall QA programme for the plant. In selecting the QA programme level for specific activities, the Code allows of a flexible approach but does not specify gradation in programme requirements. The Code is placing the burden of quality-achieving and quality-assuring functions on the task-performing organizations, namely the designers, manufacturers, constructors and plant operators. The plant owner provides for the management of the overall QA programme, surveillance of activities and verifications of the effectiveness of the constituent programmes of all project participants through programme audits and evaluations. The Code and the supporting ...
Visual Sample Plan (VSP) is an easy-to-use visual and graphic statistically-based software tool being developed by the Pacific Northwest National Laboratory (PNNL) to help determine the appropriate number and location of environmental samples so that environmental decisions can be made with the required confidence. The VSP software, which is available free at http://dqo.pnl.gov/vsp, is a significant aid in developing probability-based sampling designs (number and location of samples and measurements) using the Data Quality Objectives (DQO) planning process developed by the U.S. Environmental Protection Agency (EPA). VSP also has the capability of conducted statistical analyses to provide descriptive statistical summaries of data sets, to test whether data are normally distributed, and to compute upper confidence limits on means. This report is the latest in a series of reports that document the statistical methods used in VSP [Davidson (2001), Gilbert et al. (2001), Gilbert et a l. ...
Full text: Secure, reliable and cost-effective communications are becoming an increasingly important tool for safeguards verification. This trend began with the initiation of remote monitoring implementation, where secure and cost effective data communications were required both to satisfy the confidentiality requirements of Member States and in order to meet the rigorous data authenticity requirements which allow the International Atomic Energy Agency (IAEA) to draw credible and independent conclusions. In addition, the implementation of additional protocols and integrated safeguards increases the importance of information (obtained in the course of an inspection, visit, complementary access or design information verification) being analyzed and corroborated with other information sources stored at IAEA Headquarters or Regional Offices, often while the inspector is still on-site. This requires the capability of enabling the inspector, wherever ...
Monte Carlo simulation of beam modifiers such as physical wedges and compensating filters has been performed with a rectilinear voxel geometry module. A modified version of the EGS4/DOSXYZ code has been developed for this purpose. The new implementations have been validated against the BEAM Monte Carlo code using its standard component modules (CMs) in several geometrical conditions. No significant disagreements were found within the statistical errors of 0.5% for photons and 2% for electrons. The clinical applicability and flexibility of the new version of the code has been assessed through an extensive verification versus dosimetric data. Both Varian multi-leaf collimator (MLC) wedges and standard wedges have been simulated and compared against experiments for 6 MV photon beams and different field sizes. Good agreement was found between calculated and measured depth doses and lateral dose profiles along both wedged and unwedged directions for different depths and ...
This work describes an experimental verification of the two-photon dose calculation engines available on the Helax-TMS (version 6.1) commercial radiotherapy treatment planning system. The performance of the pencil beam convolution and the collapsed cone superposition algorithms was examined for 4, 6, 15 MV beams, under a range of clinically relevant irradiation geometries. Comparisons against measurements were carried out in terms of absolute dose, thus assessment of the accuracy of monitor unit (MU) calculations was also carried out. Results show that both algorithms agree with measurement to acceptable tolerance levels in most cases in homogeneous water-equivalent media irradiated under full scatter conditions. The collapsed cone algorithm slightly overestimates the penumbra width and this is mainly due to discretization effects of the fluence matrix. The accuracy of this algorithm strongly depends on the resolution of the patient density matrix. It is ...
The Four years of the IMPACT, 'Integrated Modular Plant Analysis and Computing Technology' project Phase 1 have been completed. The verification study of Severe Accident Analysis Code SAMPSON prototype developed in Phase 1 was conducted in two steps. First, each analysis module was run independently and analysis results were compared and verified against separate-effect test data with good results. Test data are as follows: CORA-13 (FZK) for the Core Heat-up Module; VI-3 of HI/VI Test (ORNL) for the FP Release from Fuel Module; KROTOS-37 (JRC-ISPRA) for the Molten Core Relocation Module; Water Spread Test (UCSB) for the Debris Spreading Model and Benard's Melting Test for Natural Convection Model in the Debris Cooling Module; Hydrogen Burning Test (NUPEC) for the Ex-Vessel Thermal Hydraulics Module; PREMIX, PM10 (FZK) for the Steam Explosion Module; and SWISS-2 (SNL) for the Debris-Concrete Interaction Module. Second, with the Simulation Supervisory System, up to ...
A numerical optimization technique is used to obtain low-energy momentum transfer, j = 0 [yields] 2 rotational and v = 0 [yields] vibrational sections from measured electron swarm data for parahydrogen. The downhill simplex algorithm is used to find cross sections that represent the best numerical fit to the measured electron drift velocity and characteristic energy over a range of E/N. These results, which are in excellent agreement with published cross sections derived using traditional swarm analysis techniques, demonstrates the feasibility of using automated computational algorithms for swarm analysis involving the estimation of multiple cross sections. (Author).
We study analytically and numerically the stability of the pressure-less, viscously spreading accretion ring. We show that the ring is unstable to small non-axisymmetric perturbations. To perform the perturbation analysis of the ring we use a stretching transformation of the time coordinate. We find that to 1st order, one-armed spiral structures, and to 2nd order additionally two-armed spiral features may appear. Furthermore, we identify a dispersion relation determining the instability of the ring. The theoretical results are confirmed in several simulations, using two different numerical methods. These computations prove independently the existence of a secular spiral instability driven by viscosity, which evolves into persisting leading and trailing spiral waves. Our results settle the question whether the spiral structures found in earlier simulations of the spreading ring are numerical artifacts or genuine ...
Boiling jet impingement cooling is currently being explored to cool power electronics components. In hybrid vehicles, inverters are used for DC-AC conversion. These inverters involve a number of insulated-gate bipolar transistors (IGBTs), which are used as on/off switches. The heat dissipated in these transistors can result in heat fluxes of up to 200 W/cm{sup 2}, which makes the thermal management problem quite important. In this paper, turbulent jet impingement involving nucleate boiling is explored numerically. The framework for these computations is the CFD code FLUENT. For nucleate boiling, the Eulerian multiphase model is used. The numerical results for boiling water and R113 jets (submerged) are validated against existing experimental data in the literature. Some representative IGBT package simulations that use R134a as the cooling fluid are also presented. (author)
In this paper, numerical simulation of a concentric tube heat exchanger is presented to determine the convective heat transfer coefficient and friction factor in a smooth tube. Increasing the convective heat transfer coefficient can increase heat transfer rate in a concentric tube heat exchanger from a given tubular surface area. This can be achieved by using heat transfer augmentation devices. This work constitutes the initial phase of the numerical simulation of heat transfer from tubes employing augmentation devices, such as twisted tapes, wire-coil inserts, for heat transfer enhancement. A computational fluid dynamics (CFD) simulation tool was developed with CFX software and the results obtained from the simulations are validated with the empirical correlations for a smooth tube heat exchanger. The difficulties associated with the simulation of a heat exchanger augmented with wire-coil inserts are discussed. (author)
This paper presents a numerical study on the formation history of coalbed methane (CBM) reservoir in the southeast edge of Ordos Basin, China. The coal seams studied belong to the Late Palaeozoic coal-bearing series. These coal seams have a burial history and experienced the process of subsidence, rapid subsidence alternated with uplift and then uplift, sequentially, and underwent the geothermal actions at normal, extremely high, and then normal temperatures, respectively. Coal organic matter of the coal seams matured in the Triassic Period and in the Late Jurassic to Early Cretaceous Period. The results from numerical simulation reveal that CBM reservoir evolution history can be classified into five stages, namely primary, initial, stagnant, active and dissipative stages. In the first (pr...
This paper presents results, numeric and experimental, due to installation operation of a Risers Uphold Sub-Surface Buoy, (BSR). This kind of installation developed by PETROBRAS is unique in the world. The work of BSR installation was based on a numeric pre analysis to verify the system and determine the main parameters to be experimentally verified. The second phase of the work was the experimental analysis in a deep water ocean basin. s. The work describes the BSR and their main accessories, the experimental environment and the model constructed in aluminum in a 1:12 scale and the main results. (author)
Turbulent premixed methane-air combustion in a cylindrical chamber is numerically simulated considering radiation effect. Reaction rates are considered as minimum rates between Arrhenius rates and eddy break up rates. A five step reduced mechanism is used. Turbulent modeling is done via standard k-{epsilon} model imposed by empirical inlet boundary conditions. Source terms of energy equation consist of reaction rates and radiation effects. The discrete ordinate method (DOM) is employed to solve the radiative transfer equation (RTE) and the weighted sum of gray gas model (WSGGM) is imposed to consider radiation effect of non-gray gases. The results indicate that in the case of turbulent combusting flows, the effect of radiation of gases can affect the temperature and species concentrations. The numerical results obtained considering radiation effect are closer to the experimental data than that of the case without radiation effect. (author)
Turbulent premixed methane-air combustion in a cylindrical chamber is numerically simulated considering radiation effect. Reaction rates are considered as minimum rates between Arrhenius rates and eddy break up rates. A five step reduced mechanism is used. Turbulent modeling is done via standard k-? model imposed by empirical inlet boundary conditions. Source terms of energy equation consist of reaction rates and radiation effects. The discrete ordinate method (DOM) is employed to solve the radiative transfer equation (RTE) and the weighted sum of gray gas model (WSGGM) is imposed to consider radiation effect of non-gray gases. The results indicate that in the case of turbulent combusting flows, the effect of radiation of gases can affect the temperature and species concentrations. The numerical results obtained considering radiation effect are closer to the experimental data than that of the case without radiation effect.
Baxter (Australas J Philos 79:449?464, 2001) proposes an ingenious solution to the problem of instantiation based on his theory of cross-count identity. His idea is that where a particular instantiates a universal it shares an aspect with that universal. Both the particular and the universal are numerically identical with the shared aspect in different counts. Although Baxter does not say exactly what a count is, it appears that he takes ways of counting as mysterious primitives against which different numerical identities are defined. In contrast, I defend the idea?suggested, though not quite endorsed, by Baxter himself?that counts are independent dimensions of numerical identity. Different ways of counting are explained by the existence of these different sorts of identity (i.e., counts)...
We present a new set of 3.5 Post-Newtonian equations in which Newtonian hydrodynamics is coupled to the nonconservative effects of gravitational radiation emission. Our formalism differs in two significant ways from a similar 3.5 Post-Newtonian approach proposed by Blanchet (1993, 1997). Firstly we concentrate only on the radiation-reaction effects produced by a time-varying mass-current quadrupole $S_{ij}$. Secondly, we adopt a gauge in which the radiation-reaction force densities depend on the fourth time derivative of $S_{ij}$, rather than on the fifth, as in Blanchet's approach. This difference makes our formalism particularly well-suited to numerical implementation and could prove useful in performing fully numerical simulations of the recently discovered $r$-mode instability for rotating neutron stars subject to axial perturbations.
Results from a numerical model of axisymmetric solar cavity receivers are compared with experimental data for tests of a novel test bed receiver in the Saudi National Laboratories solar furnace. The computed energy transfer rates and temperatures are compared with the experimental data for different receiver geometries, aperture sizes, and operating conditions. In general, the agreement between the numerical model and the experimental data is better for the small-to-midsized apertures than for the large apertures. The analysis indicates that for the larger apertures, the convective heat losses are overpredicted. It also suggests that these losses could be better characterized. Sensitivity analyses show that both the total solar energy input rate and the convective heat-loss coefficient significantly affect the receiver thermal performance and that the distribution of the input solar flux significantly affects the temperature distribution in the ...
The control volume finite element method (CVFEM) was developed to combine the local numerical conservation property of control volume methods with the unstructured grid and generality of finite element methods (FEMs). Most implementations of CVFEM include mass-lumping and upwinding techniques typical of control volume schemes. In this work we compare, via numerical error analysis, CVFEM and FEM utilizing consistent and lumped mass implementations, and stabilized Petrov-Galerkin streamline upwind schemes in the context of advection-diffusion processes. For this type of problem, we find no apparent advantage to the local numerical conservation aspect of CVFEM as compared to FEM. The stabilized schemes improve accuracy and degree of positivity on coarse grids, and also reduce iteration counts for advection-dominated problems.
Heterogeneous anisotropic diffusion problems arise in the various areas of science and engineering including plasma physics, petroleum engineering, and image processing. Standard numerical methods can produce spurious oscillations when they are used to solve those problems. A common approach to avoid this difficulty is to design a proper numerical scheme and/or a proper mesh so that the numerical solution validates the discrete counterpart (DMP) of the maximum principle satisfied by the continuous solution. A well known mesh condition for the DMP satisfaction by the linear finite element solution of isotropic diffusion problems is the non-obtuse angle condition that requires the dihedral angles of mesh elements to be non-obtuse. In this paper, a generalization of the condition, the so-called anisotropic non-obtuse angle condition, is developed for the finite element solution of heterogeneous anisotropic diffusion problems. ...
Proteinaceous aggregation occurs through self-assembly-- a process not entirely understood. In a recent article [1], an analytical theory for amyloid fibril growth via secondary rather than primary nucleation was presented. Remarkably, with only a single kinetic parameter, the authors were able to unify growth characteristics for a variety of experimental data. In essence, they seem to have uncovered the underlying allometric laws governing the evolution of filament elongation simply from two coupled non-linear ordinary differential equations (ODEs) stemming from a master equation. While this work adds significantly to our understanding of filament self-assembly, it required an approximate analytical solution representation. Here, we show that the same results are found by purely numerical means once a straightforward and reliable numerical solution to the set of ODEs has been established.
Ultra-short-pulse reflectometry is studied by means of the numerical integration of a one-dimensional full-wave equation for ordinary modes propagating in a plasma. The numerical calculations illustrate the potential of using the reflection of ultra-short-pulse, microwaves as an effective probe of the density profile even in the presence of significant density fluctuations. The difference in time delays of differing frequency components of the microwaves can be used to deduce the density profile. The modification of the reflected pulses in the presence of density fluctuations is examined and can be understood based on considerations of Bragg resonance. A simple and effective profile-reconstruction algorithm using the zero-crossings of the reflected pulse and subsequent Abel inversion is demonstrated. The robustness of the profile reconstruction algorithm in the presence of a sufficiently small amplitude density perturbation is assessed.
A combined numerical and theoretical study is conducted herein on the penetration of semi-infinite targets by jacketed rods with different r"j"0/r"c"0 ratios where r"j"0 and r"c"0 are the radii of the jacket and the core, respectively. The numerical results show that for smaller r"j"0/r"c"0 ratios the u-v relationship changes only a little compared to that of unitary long rod penetrator of the same core material, hence, the u-v relationship of unitary (homogeneous) long rod penetration is also applicable for jacketed rod penetration. Model for cratering in semi-infinite targets by jacketed rods is then suggested by using the laws of conversation of mass, momentum and energy, together with the u-v relationship of unitary (homogeneous) long rod penetration and an analytical model for predict...
A three-dimensional (3D) thermal-hydraulic model and a numerical procedure for the simulation and analysis of a steady-state, as well as transient operation of nuclear power plant components are presented. A two-fluid approach is applied to modelling of two-phase flow. Thermal-hydraulics of a horizontal steam generator in the WWER 1000 nuclear power plant has been simulated at the full load, steady-state operation. A comparison of the numerical results with data measured at the NPP Novovoronjezh shows good agreement. 3D numerical results can be used in plant design or retrofitting, in nuclear power plant operation and safety analysis and as improvement of existing one-dimensional thermal-hydraulics models of the horizontal steam generator which are assessed by system codes used for the nuclear power plant safety analyses. (author)
A three-dimensional (3D) thermal-hydraulic model and a numerical procedure for the simulation and analysis of a steady-state, as well as transient operation of nuclear power plant components are presented. A two-fluid approach is applied to modelling of two-phase flow. Thermal-hydraulics of a horizontal steam generator in the WWER 1000 nuclear power plant has been simulated at the full load, steady-state operation. A comparison of the numerical results with data measured at the NPP Novovoronjezh shows good agreement. 3D numerical results can be used in plant design or retrofitting, in nuclear power plant operation and safety analysis and as improvement of existing one-dimensional thermal-hydraulics models of the horizontal steam generator which are assessed by system codes used for the nuclear power plant safety analyses. (author)
We present the general properties of the far-ultraviolet (FUV; 1370-1720A) continuum background over most of the sky, obtained with the Spectroscopy of Plasma Evolution from Astrophysical Radiation instrument (SPEAR, also known as FIMS), flown aboard the STSAT-1 satellite mission. We find that the diffuse FUV continuum intensity is well correlated with N_{HI}, 100 $\\mu$m, and H-alpha intensities but anti-correlated with soft X-ray. The strongest correlation is with the H-alpha emission, and the correlation of the diffuse background with the direct stellar flux is weaker than the correlation with other parameters. The continuum spectra are relatively flat. However, a weak softening of the FUV spectra toward some sight lines, mostly at high Galactic latitudes, is found not only in direct-stellar but also in diffuse background spectra. The diffuse background is relatively softer that the direct stellar ...
It has been proposed that a hidden conformal field theory (CFT) governs the dynamics of low frequency scattering in a general Kerr black hole background. We further investigate this correspondence by mapping higher order corrections to the massless wave equations in a Kerr background to an expansion within the CFT in terms of higher dimension operators. This implies the presence of infinite towers of CFT primary operators with positive conformal dimensions compatible with unitarity. The exact Kerr background softly breaks the conformal symmetry and the scaling dimensions of these operators run with frequency. The scale-invariant fixed point is dual to a degenerate case of flat spacetime.
In many industrialised societies, women remain underrepresented in the sciences, which can be predicted by the gender gap in math achievement at school. Using PISA 2006 data, we explore the role of family background and single-sex schooling in girls' disadvantage in maths in South Korea and Hong Kong. This disadvantage is found to be associated with single-sex schooling, but not with family background. Attending a girls' school confers a benefit only in South Korea, whereas the gendered curriculum counteracts the selectivity advantage of girls' schools in Hong Kong. We find that a gendered social structure prevalent in both societies.
BackgroundDuplications of stretches of the genome are an important source of individual genetic variation, but their unrecognized presence in laboratory organisms would be a confounding...Full Text Available
BackgroundApproximately 25% of ischemic stroke patients awaken with neurological deficits. In these patients, in whom the time from symptom onset is uncertain, brain imaging is a...Full Text Available
BackgroundThe WINPEPI computer programs for epidemiologists are designed for use in practice and research in the health field and as learning or teaching aids. The programs are free,...Full Text Available
BackgroundOxidative stress has been proposed as a mechanism linking the poor placental perfusion characteristic of preeclampsia with the clinical manifestations of...Full Text Available
Background. The role of vitamin D in the body's ability to fight influenza and URI's may be dependent on regulation of specific cytokines that participate in the host inflammatory...Full Text Available
BackgroundVisual acuity, the ability of the visual system to distinguish two separate objects at a given angular distance, is influenced by the optical and neuronal properties of...Full Text Available
A new estimator of the local density of dark energy is suggested which comes from the virial theorem for non-relativistic gravitating systems embedded in the uniform dark energy background.
Background and ObjectivePulsed dye laser (PDL) treatment of cutaneous vascular lesions is associated with variable and unpredictable efficacy. Thus, alternative treatment...Full Text Available
BackgroundThe endoscopic endonasal transsphenoidal approach (EETA) to the pituitary is performed by ear, nose, and throat (ENT) surgeons in collaboration with neurosurgeons but also...Full Text Available
BackgroundUse of Traditional Chinese medicine (TCM), an important category of complementary and alternative medicine (CAM), has increased substantially in Western countries during...Full Text Available
BackgroundIncrease in the incidence of hyperuricemia associated with gout as well as hypertension, renal diseases and cardiovascular diseases has been a public health concern. We...Full Text Available
In this survey paper, we present open problems and conjectures on visibility graphs of points, segments and polygons along with necessary backgrounds for understanding them.
BackgroundLate-onset sepsis in the premature infant is frequently revealed by severe, unusual and recurrent bradycardias. In view of the high morbidity and mortality...Full Text Available
BackgroundFeature selection is an important pre-processing task in the analysis of complex data. Selecting an appropriate subset of features can improve classification or clustering...Full Text Available
BackgroundSister species divergence and reproductive isolation commonly results from ecological adaptation. In mimetic Heliconius butterflies, shifts in colour pattern...Full Text Available
BackgroundThe evolution of eukaryotic cells is widely agreed to have proceeded through a series of endosymbiotic events between larger cells and proteobacteria or cyanobacteria,...Full Text Available
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
BACKGROUND: This prospective and retrospective study carried out over a period of one month (50 patients) looked at the quality of hospital records of urethral catheterisation with reference to the...Full Text Available
BackgroundDiscrepancies between the conclusions of different meta-analyses (quantitative syntheses of systematic reviews) are often ascribed to methodological differences. The objective...Full Text Available
BackgroundCharacterization of the innate immune repertoire of extant cnidarians is of both fundamental and applied interest - it not only provides insights into the basic immunological...Full Text Available
Background:To encourage evidence-based practice, an Annals of Internal Medicine editorial called for a new professional on clinical teams: an informationist trained...Full Text Available
BackgroundProfessionalism is a critical quality for physicians to possess. Physician professionalism has received increased attention in recent years, with many authorities suggesting...Full Text Available
BackgroundLow back pain (LBP) is the most prevalent musculoskeletal condition and one the most common causes of disability in the developed nations. Anecdotally, there is a general...Full Text Available
Background:Spina bifida presents a significant cause of childhood morbidity in lower- and middle-income nations. Unfortunately, there is a paucity of literature examining...Full Text Available
BackgroundThe availability of multiple, essentially complete genome sequences of prokaryotes and eukaryotes spurred both the demand and the opportunity for the construction of an...Full Text Available
BackgroundBlindness due to trachoma is avoidable through Surgery, Antibiotics, Facial hygiene and Environmental improvements (SAFE). Recent surveys have shown trachoma to be a serious...Full Text Available
BackgroundUnderstanding the mechanisms that control rates of disease progression in humans and other species is an important area of research relevant to epidemiology and to translating...Full Text Available
Background/Objective:Tarlov cysts or spinal perineurial cysts are uncommon lesions. These are mostly incidental findings on magnetic resonance imaging or myelograms. The...Full Text Available
Background:Prolonged mechanical ventilation is increasingly common. It is expensive and associated with significant morbidity and mortality. Our objective is to comprehensively characterize...Full Text Available
BackgroundThe routine removal of orthopaedic fixation devices after fracture healing remains an issue of debate. There are no evidence-based guidelines on this matter, and little...Full Text Available
BackgroundElementary schools represent both a source of childhood sun exposure and a setting for educational interventions.MethodsSun Protection...Full Text Available
BackgroundWith the exception of vertebrates, most organisms have plasma membrane associated ammonium transporters which primarily serve to import a source of nitrogen for nutritional...Full Text Available
Background:Solid pseudopapillary tumor is a rare pancreatic neoplasm with uncertain to low malignant potential. This is an uncommon neoplasm with many pseudonyms, occurring...Full Text Available
BackgroundTacrolimus (FK-506) is an immunosuppressant that binds to a specific immunophilin, resulting in the suppression of the cellular immune response during transplant rejection....Full Text Available
BackgroundCystic neoplasms of the pancreas are less common than solid tumors, and portend a better prognosis. They can be divided into serous and mucinous subtypes, with the former...Full Text Available
BackgroundTo identify the differential tuberculosis (TB) characteristics within the immigrant population with respect to natives in Spain.Methodology/Principal...Full Text Available
BackgroundTo investigate the significance of Aurora B expression in hepatocellular carcinoma (HCC).MethodsThe Aurora B and Aurora...Full Text Available
BackgroundAlternative splicing is an important mechanism mediating the diversified functions of genes in multicellular organisms, and such event occurs in around 40-60% of human...Full Text Available
BackgroundCharacterizing and comparing the determinant of cotinine concentrations in different populations should facilitate a better understanding of smoking patterns and addiction....Full Text Available
BackgroundNonsteroidal anti-inflammatory drugs are commonly used to treat postoperative and chronic pain. Animal studies suggest these drugs act in part by blocking...Full Text Available
BackgroundMost reports of scientific misconduct have been focused on principal investigators and other scientists (e.g., biostatisticians) involved in the research...Full Text Available
Background The Internet is becoming an increasingly important resource for health-information seekers. However, consumers often do not use effective search...Full Text Available
BACKGROUND: An approach to the study of the pharmacokinetics of drugs in the lung is to measure their concentrations in bronchial biopsy specimens. The main criticism of this technique is that bronchial...Full Text Available
BackgroundBrucellosis is a zoonosis of veterinary, public health and economic significance in most developing countries. Human brucellosis is a severely debilitating disease that...Full Text Available
BackgroundProvision of consumer information and patient education are considered an essential part of chronic disease management programmes developed for patients with heart failure....Full Text Available
BackgroundWhether psychological resilience correlates with neurocognitive performance is largely unknown. Therefore, we assessed association between neurocognitive...Full Text Available
BackgroundOrthology analysis is an important part of data analysis in many areas of bioinformatics such as comparative genomics and molecular phylogenetics. The ever-increasing flood...Full Text Available
BackgroundHealth service databases of administrative type can be a useful tool for the study of progression of a disease, but the data reported in such sources could be affected...Full Text Available
Background/Aim:To assess the prognostic indicators preoperatively presenting and influencing the mortality rate following esophagectomy for esophageal cancer.Full Text Available
BackgroundPolybrominated diphenyl ethers (PBDEs) are widely used flame retardant compounds that are persistent and bioaccumulative and therefore have become ubiquitous environment...Full Text Available
BackgroundStatistical autoregressive analyses of direct and delayed density dependence are widespread in ecological research. The models suggest that changes in ecological factors...Full Text Available
BackgroundPreclinical models of pediatric cancers are essential for testing new chemotherapeutic combinations for clinical trials. The most widely used ...Full Text Available
BackgroundBisphenol A (BPA) is a high-production-volume chemical commonly used in the manufacture of polycarbonate plastic. Low-level concentrations of BPA in animals and possibly...Full Text Available
BackgroundEmphysematous cholecystitis is a variant of acute cholecystitis which is generally caused by gas-forming organisms. Emphysematous cholecystitis may cause gas spreading...Full Text Available
BackgroundPlasmodium falciparum is the most malignant agent of human malaria. It belongs to the taxon Laverania, which includes other ape-infecting Plasmodium...Full Text Available
BackgroundSection Calochroi is one of the most species-rich lineages in the genus Cortinarius (Agaricales, Basidiomycota) and is widely distributed...Full Text Available
BackgroundPhotorhabdus luminescens is a Gram-negative luminescent enterobacterium and a symbiote to soil nematodes belonging to the species Heterorhabditis...Full Text Available
BackgroundThe monolignol biosynthetic pathway interconnects with the biosynthesis of other secondary phenolic metabolites, such as cinnamic acid derivatives, flavonoids and condensed...Full Text Available
OBJECTIVE: New surgical procedures designed to assist in the treatment of peritoneal surface malignancy were sought. BACKGROUND: Decisions regarding the treatment of cancer depend on the anatomic location...Full Text Available
BackgroundSeveral studies have suggested an association between periodontal disease and prematurity but this finding has not been consistently observed.MethodsCase...Full Text Available
Background:Percutaneous tracheostomy (PT) has gained an increasing acceptance as an alternative to the conventional surgical tracheostomy (ST). In experienced hands, and with...Full Text Available
BACKGROUND:In adults, it is well known that high levels of pain catastrophizing are related to increased pain and disability as well as to heightened anxiety and depression. However,...Full Text Available
BACKGROUND:Despite increasing attention to the epidemiology of pain, relatively little is known about the association between pain and health in children. In particular, no studies...Full Text Available
BackgroundGenetic predisposition to scrapie in sheep is associated with several variations in the peptide sequence of the prion protein gene (PRNP). DNA-based tests...Full Text Available
BackgroundMedication errors are common among inpatients and many are preventable with computerized prescribing. Relatively little is known about outpatient prescribing errors or...Full Text Available
BackgroundTitanium and titanium alloys are widely used for fabrication of dental implants. Since the material composition and the surface topography of a biomaterial play a fundamental...Full Text Available
BackgroundBisphenol A (BPA) is widely used in the manufacture of polycarbonate plastics, including infant formula bottles.ObjectivesBased on the...Full Text Available
BackgroundPrior research links optimism to physical health, but the strength of the association has not been systematically evaluated.PurposeFull Text Available
OBJECTIVE: This study evaluated, in a large, heterogeneous population, the outcome of open cholecystectomy as it is currently practiced. SUMMARY BACKGROUND AND DATA: Although cholecystectomy has been...Full Text Available
BackgroundSoft tissue foreign bodies are a common cause of orthopedic consultation in emergency departments. It is difficult to confirm their existence because conventional radiology...Full Text Available
BackgroundChanges in levels of estradiol and progesterone that occur with the transition to reproductive senescence may influence nociception or affect.Full Text Available
BackgroundMovement regularities are inherently present in automated goal-directed motions of the primate's arm system. They can provide important signatures of intentional behaviours...Full Text Available
BackgroundCo-flowering plant species frequently share pollinators. Pollinator sharing is often detrimental to one or more of these species, leading to competition for pollination....Full Text Available
BackgroundThe ongoing epidemiological transition in Mexico minimizes the relative impact of neurocysticercosis (NC) on public health. However, hard data on the disease frequency...Full Text Available
... and support cost, and post-retirement disposal cost) of ... from reactors, and the reactors and other ... the ship's hull and reactor compartment enough to ...
Background and PurposeHemodynamic insults at arterial bifurcations are hypothesized to play a key role in intracranial aneurysm formation. This study investigates...Full Text Available
Background: The nail gun is a commonly utilized tool in carpentry and construction. When used properly with appropriate safety precautions, it can facilitate production and boost efficiency;...Full Text Available
BackgroundMucinous cystic neoplasm (MCN) of the pancreas is basically cystic epithelial neoplasm, unilocular or multilocular, occurring almost exclusively in women.Case...Full Text Available
BackgroundStump and phantom pains are debilitating sequelae of amputations that are often resistant to treatment. The efficacy of pharmacologic therapies, including...Full Text Available
BackgroundBorrelia lonestari infects Amblyomma americanum, the tick species that is the most common cause of tick bites in southeast...Full Text Available
BackgroundMolecular genetic studies of Bombyx mori have led to profound advances in our understanding of the regulation of development. Bombyx mori brain,...Full Text Available
BackgroundAs long-term nursing home care is likely to increase with the aging of the population, identifying chronic medical conditions is of particular interest. Although need factors...Full Text Available
Background: Contamination of autologous grafts unfortunately occurs in plastic surgery, but the literature provides no guidance for management of such incidents. Methods: American...Full Text Available
Background. The coexistence of neoplasm and abdominal aortic aneurysm (AAA) presents a real management challenge. This paper reviews the literature on the prevalence, diagnosis,...Full Text Available
BackgroundMalaria is one of the most important tropical diseases that affects people globally. The influence of environmental conditions in the patterns of temporal distribution...Full Text Available
Effective localization of small magnets against a noisy, real world background can involve various methods to first identify the magnetic fields produced by the magnet of interest, then to filter out background noise, and then to analyze the available magnetic field data to localize the magnet. Here we discuss low cost techniques which allow localization of small magnets with field strengths in the milliGauss range against real world background fields in the range of hundreds of mG, which may be fluctuating by up to tens of mG. Such techniques allow magnet tracking to be used to localize catheters in place of more invasive and expensive methods, e.g. fluoroscopy, for a variety of applications, including drug infusion with peripherally inserted central catheters (PICCs), laser ablation (TMR, PTMR) and introduction of pacemaker leads.
BackgroundAlthough local excision (ampullectomy) was first described by Halsted in 1899, its adequacy as an alternative surgical treatment for the ampullary tumors is still a matter...Full Text Available
BackgroundLymphangioleiomyomatosis (LAM) is a rare lung disease characterised by progressive airflow obstruction. No effective medical treatment is available but therapy with sirolimus...Full Text Available
Background and AimsIt is well known that genome size differs among species. However, information on the variation and dynamics of genome size in wild populations and on the early...Full Text Available
BackgroundIt is well established that Legionella pneumophila is a waterborne pathogen; by contrast, the mode of Helicobacter pylori transmission...Full Text Available
BackgroundFloating knee injuries are usually associated with other significant injuries. Do these injuries have implications on the management of the floating knee and the final...Full Text Available
Background An increasing number of people have access to the Internet, and more people are seeking tobacco cessation resources online every year. Despite the...Full Text Available
• Background and Aims The occurrence of stomata in seed coats is uncommon and there is limited information about their function(s). The aim of this study was to verify the distribution...Full Text Available
BackgroundMany molecules of interest are flexible and undergo significant shape deformation as part of their function, but most existing methods of molecular shape comparison (MSC)...Full Text Available
BackgroundWhereas there is increasing evidence that loss of expression and/or function of the thyroid hormone receptors (TRs) could result in a selective advantage for tumor development,...Full Text Available
BackgroundAlterations in protein composition and oxidative damage of high-density lipoprotein (HDL) have been proposed to impair the cardioprotective properties of...Full Text Available
BackgroundIn biomedical ontologies, mereological relations have always been subject to special interest due to their high relevance in structural descriptions of anatomical entities,...Full Text Available
ObjectiveTo assess the utility of gracilis muscle transposition in the treatment of iatrogenic rectourethral fistula.Summary Background DataIatrogenic...Full Text Available
BackgroundRecent studies have shown associations between size and body proportions at birth and health outcomes throughout the life cycle, but there are few data...Full Text Available
BackgroundGender is a critically important moderator of psychopathology. However, gender similarities and differences in body dysmorphic disorder (BDD) have received...Full Text Available
BackgroundThe use of fractionated stereotactic radiotherapy (fsrt) has evolved with technical advances in noninvasive immobilization, radiation delivery, and image guidance....Full Text Available
BackgroundSeveral fractal and non-fractal parameters have been considered for the quantitative assessment of the vascular architecture, using a variety of test specimens and of computational...Full Text Available
Background and AimsAnnonaceae are one of the largest families of Magnoliales. This study investigates the comparative floral development of 15 species to understand the basis for...Full Text Available
Background and objectives: Despite potential significance of fatigue and its underlying components in the occurrence of cardiovascular diseases, epidemiologic data showing the link are virtually limited....Full Text Available
BackgroundSenescence is integral to the flowering plant life-cycle. Senescence-like processes occur also in non-angiosperm land plants, algae and photosynthetic prokaryotes. Increasing...Full Text Available
BackgroundEnzyme-linked immunosorbent assay (ELISA) is a standard immunoassay to estimate a protein's concentration in a sample. Deploying ELISA in a microarray format permits simultaneous...Full Text Available
BackgroundSwine is an important agricultural commodity and biomedical model. Manipulation of the pig genome provides opportunity to improve production efficiency, enhance disease...Full Text Available
This article examines how politics and science interacted against a background of uncertainty to shape policy in the case of environmental contamination by polybrominated biphenyls (PBB) in Michigan....Full Text Available
BackgroundThrough differentiation processes, keratinocytes provide a physical barrier to our bodies and control skin features such as moisturization, wrinkles and pigmentation. Keratinocyte...Full Text Available
Background:Since first reported in 1996, endoscopic minimally invasive surgery of the cervical region has been shown to be safe and effective in the treatment of benign thyroid and...Full Text Available
BackgroundMutations that disrupt the conversion of prelamin A to mature lamin A cause the rare genetic disorder Hutchinson-Gilford progeria syndrome and a group of laminopathies....Full Text Available
Background:People with severe and persistent mental illness need help in most aspects of their lives, as the disability associated with these diseases can be debilitating....Full Text Available
BackgroundTo investigate the effects of intravenous lignocaine infusions (IV lignocaine) in fibromyalgia.MethodsProspective study...Full Text Available
BackgroundThe National Cancer Institute has concluded that exposure to smoking in movies causes adolescent smoking and there are similar results for young adults.Full Text Available
BackgroundThe aim of this report was to describe duodenal obstruction caused by a rubber foreign body in a cow.Case PresentationThe clinical, biochemical...Full Text Available
BackgroundThere is no data documenting the existence of a risk of infection transmission in ambulatory healthcare settings but concern remains. Our objective was to determine the...Full Text Available
BackgroundPerfluoroalkyl acids (PFAAs) are found globally in wildlife and humans and are suspected to act as endocrine disruptors. There are no previous reports of PFAA levels in...Full Text Available
Background:Frozen shoulder (FS) is a debilitating musculoskeletal condition with an uncertain etiology and pathogenic mechanism. The aim of this study was to investigate...Full Text Available
Does the cultural background influence the success with which genetically unrelated individuals cooperate in social dilemma situations? In this paper, we provide an answer by analysing the data of Full Text Available
BACKGROUND: Cuba's response to the human immunodeficiency virus (HIV) epidemic has been to conduct mass testing of the population to ascertain seroprevalence, to enforce mandatory relative quarantine...Full Text Available
BackgroundInternet-based depression communities provide a forum for individuals to communicate and share information and ideas. There has been little research into the health status...Full Text Available
BackgroundAlthough advances in rehydration therapy have made cholera a treatable disease with low case-fatality in settings with appropriate medical care, cholera continues...Full Text Available
BackgroundClostridium botulinum produces seven distinct serotypes of botulinum neurotoxins (BoNTs). The genes encoding different subtype neurotoxins of serotypes...Full Text Available
BackgroundPublicly available DNA sequence databases such as GenBank are large, and are growing at an exponential rate. The sheer volume of data being dealt with presents serious...Full Text Available
BackgroundHypertension is a common non communicable condition worldwide. In developing countries (including Nigeria), the use of complementary and alternative medicine (CAM) is common....Full Text Available
BackgroundIn nuclear medicine, liquid radiopharmaceuticals for diagnostic or therapeutic purposes are administered to patients by using various types of syringes with different volumes....Full Text Available
BackgroundNucleotide sequences and the gene arrangements of mitochondrial genomes are effective tools for resolving phylogenetic problems. Hemipteroid insects are known to possess...Full Text Available
BackgroundAutofluorescence bronchoscopy is more sensitive than conventional bronchoscopy for detecting early airway mucosal lesions. Decreased specificity can lead...Full Text Available
BackgroundA mycovirus previously identified in brown discolored fruiting bodies of the cultivated mushroom Flammulina velutipes was characterized. We tentatively...Full Text Available
Background:Cemented hip arthroplasty is an established treatment for femoral neck fracture in the mobile elderly. Cement pressurization raises intramedullary pressure and...Full Text Available
Background Increasing numbers of cancer patients are using the Internet, but little is known about their attitudes toward online health care.Full Text Available
BackgroundCystinuria is the most common inherited cause of urinary tract stones in children. It can lead to obstructive uropathy, which is a major cause of renal...Full Text Available
Background:To determine nutrient requirements by the carbon oxidation techniques, it is necessary to know the fraction of carbon dioxide produced during the oxidative...Full Text Available
BackgroundOsseointegration is crucial for the long-term success of dental implants and depends on the tissue reaction at the tissue-implant interface. Mechanical properties and biocompatibility...Full Text Available
BackgroundThe metagenomic analysis of microbial communities holds the potential to improve our understanding of the role of microbes in clinical conditions. Recent, dramatic improvements...Full Text Available
BackgroundMeasures of attachment style are often used to appraise social and emotional health. In developmental literature, the concept of attachment is used to explain...Full Text Available
BackgroundThe purpose of this research was to examine whether waterpipe smokers experience increased risk of motor vehicle crashes.MethodsIn a telephone...Full Text Available
BackgroundArtificial duplicates from pyrosequencing reads may lead to incorrect interpretation of the abundance of species and genes in metagenomic studies. Duplicated reads were...Full Text Available
BackgroundObsessive-compulsive disorder is associated with a relevant impairment in social and interpersonal functioning and severe disability. This seems to be particularly true...Full Text Available
BackgroundThe aim of this study was to investigate the anticancer activity and mechanism of action of Noscapine alone and in combination with Doxorubicin against triple negative...Full Text Available
Background"Nubiotics" are synthetic oligonucleotides and nucleotides with nuclease-resistant backbones, and are fully protonated for enhanced ability to be taken up by bacterial...Full Text Available
BackgroundArtocarpus communis is used traditionally in Cameroon to treat several ailments, including infectious and associated diseases. This work was therefore...Full Text Available
BackgroundPoliovirus, the causative agent of poliomyelitis, is a human enterovirus and a member of the family of Picornaviridae and among the most rapidly evolving viruses known....Full Text Available
BackgroundHearing loss is a common sensory disorder, yet prospective data on potentially modifiable risk factors are limited. Regularly used analgesics, the most...Full Text Available
BackgroundThe function of a cylinder allowing simultaneous measurements of the opposition axis of the index finger and thumb of the hand and the magnitude of pinch force is described.Full Text Available
Background:Antimicrobial agents have been used as a chemotherapeutic agent to improve oral health. This in vitro study was carried out to determine the antimicrobial activity...Full Text Available
BackgroundFunction exertion of specific proteins are key factors in disease progression, thus the systematical identification of those specific proteins is a prerequisite to understand...Full Text Available
Background/Objectives:Imaging technology is an important part of the diagnosis and management of spinal trauma. Indications and findings in post-traumatic imaging of the vertebral...Full Text Available
SummaryBackgroundMalaria, a non-fatal disease if detected promptly and treated properly, still causes many deaths in malaria-endemic countries with...Full Text Available
Background:Alopecia areata (AA) is an immune-mediated form of hair loss that occurs in all ethnic groups, ages, and both sexes. Helicobacter pylori has...Full Text Available
BackgroundGhana has not conducted a national tuberculin survey or tuberculosis prevalence survey since the establishment of the National Tuberculosis Control Programme. The primary...Full Text Available
BackgroundMultilevelness is a defining characteristic of complex systems. For example, in the intestinal tissue the epithelial lining is organized into crypts that are maintained...Full Text Available
BackgroundThe evaluation of interventions and policies designed to promote resilience, and research to understand the determinants and associations, require reliable and valid measures...Full Text Available
BackgroundThe permeabilization of mitochondrial membranes is a decisive event in apoptosis or necrosis culminating in cell death. One fundamental mechanism by which...Full Text Available
BackgroundMultiple myeloma is a hematologic malignancy associated with the development of a destructive osteolytic bone disease.ResultsMathematical...Full Text Available
BackgroundMany difficult problems in evolutionary genomics are related to mutations that have weak effects on fitness, as the consequences of mutations with large effects are often...Full Text Available
BackgroundAmino-terminal signal peptides (SPs) are short regions that guide the targeting of secretory proteins to the correct subcellular compartments in the cell. They are cleaved...Full Text Available
BackgroundAdnexal masses are not uncommon in patients with breast cancer. Breast cancer and ovarian malignancies are known to be associated. In patients with breast cancer and co-existing...Full Text Available
BackgroundAdequate pain assessment is critical for evaluating the efficacy of analgesic treatment in clinical practice and during the development of new therapies. Yet the currently...Full Text Available
BackgroundMycobacterium avium subspecies paratuberculosis causes systemic infection and chronic intestinal inflammation in many species including...Full Text Available
BackgroundMitochondrial DNA (mtDNA) is being analyzed by an increasing number of laboratories in order to investigate its potential role as an active marker of tumorigenesis...Full Text Available
The continuing rapid increase in available computing power has not reduced the importance of efficient methods of optical system assessment for automatic lens design. On the contrary, the new capabilities simply show that truly automatic optical design wi...
Operation of an X-ray spectrometer based on a spherical variable-line-spacing (VLS) grating is analyzed using dedicated ray-tracing software allowing fast optimization of the grating parameters and...Full Text Available