145 research outputs found
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Covariance Workshop. April 22-23, 1999 Brookhaven National Laboratory
The NCSP is a comprehensive program established to help assure continued safe, efficient operations with fissile materials in the US. The major Tasks included in the NCSP are Critical Experiments, Benchmark Evaluations, Analytical Methods, Applicable Ranges of Bounding Curves and Data (AROBCAD), Information Preservation and Dissemination, Training and Qualification, and Nuclear Data. The Nuclear Data Task provides newly measured differential data and newly evaluated nuclear data for use in analyses of fissile material systems. One feature of the effort to improve the nuclear data for criticality applications is the inclusion of covariance data and sensitivity parameters that then allows the analyst to assess the uncertainty in calculated performance parameters due to uncertainties in the nuclear data. A characteristic of currently available nuclear data libraries is a lack of such covariance information. It was felt that gathering noted experts in the field would help assess the current status and offer guidance to the NCSP Nuclear Data Task on how to proceed in developing covariance information useful for criticality safety analysts. Since many of the experts in the field are in the international community, we scheduled the Workshop to be held just prior to a meeting of the OECD Nuclear Energy Agency Working Party on Evaluation Cooperation (WPEC). Hence, the Nuclear Data Covariance Workshop, held April 22-23, 1999 at Brookhaven National Laboratory, was able to attract 28 experts from 16 institutes in 8 countries to help assess the status of nuclear data covariance information. The presentations and discussions focused on practical technical matters associated with the generation of covariance matrices, formats for covariance matrices (particularly for evaluated files), mathematical issues related to the manipulation of covariances, and applications for covariance matrices. This publication provides a means of documenting the formal and informal presentations. The chairs of the four sessions also provided a summary of the discussions and exchange of ideas that took place. The meeting provided a rekindling of interest in this important area of work and representatives of the various international cross-section libraries were supportive of the efforts being made in the NCSP to provide evaluated data files with comprehensive covariance information. It is recommended that Workshops of this kind be planned for the future and the additional activities related to nuclear data covariances be included in the program of the NEA/NCS WPEC
The information analysis center concept as developed by the Radiation Shielding Information Center in its computer codes activities
Information analysis center concept and computer codes for calculating radiation transport, and shield design
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Available computer codes and data for radiation transport analysis
The Radiation Shielding Information Center (RSIC), sponsored and supported by the Energy Research and Development Administration (ERDA) and the Defense Nuclear Agency (DNA), is a technical institute serving the radiation transport and shielding community. It acquires, selects, stores, retrieves, evaluates, analyzes, synthesizes, and disseminates information on shielding and ionizing radiation transport. The major activities include: (1) operating a computer-based information system and answering inquiries on radiation analysis, (2) collecting, checking out, packaging, and distributing large computer codes, and evaluated and processed data libraries. The data packages include multigroup coupled neutron-gamma-ray cross sections and kerma coefficients, other nuclear data, and radiation transport benchmark problem results. (auth
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Computer codes and data available from the Radiation Shielding Information Center
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BUGLE-96: A revised multigroup cross section library for LWR applications based on ENDF/B-VI Release 3
A revised multigroup cross-section library based ON ENDF/B-VI Release 3 has been produced for light water reactor shielding and reactor pressure vessel dosimetry applications. This new broad-group library, which is designated BUGLE-96, represents an improvement over the BUGLE-93 library released in February 1994 and is expected to replace te BUGLE-93 data. The cross-section processing methodology is the same as that used for producing BUGLE-93 and is consistent with ANSI/ANS 6.1.2. As an added feature, cross-section sets having upscatter data for four thermal neutron groups are included in the BUGLE-96 package available from the Radiation Shielding Information Center. The upscattering data should improve the application of this library to the calculation of more accurate thermal fluences, although more computer time will be required. The incorporation of feedback from users has resulted in a data library that addresses a wider spectrum of user needs
The Grizzly, September 28, 1993
The Quilt\u27s Arrival: To Remember • Dawleys Appointed Biology Co-Chairs • Russian President Yeltsin Dissolves Parliament • Model UN Seeks New Delegation • Billy Joel Rocks Philly • Javapalooza • Big Al Day Exposed • Fitness Forum • Freshman Primer • Letter: Faculty Members Point Out Error • Tutorial Program Strengthens Ursinus • Ursinus Perceived as Anti-Gay • UC Training Staff Saves the Day • Bear Pack Way Ahead Again • Football Holds Off Western Maryland • Scooter\u27s Dayhttps://digitalcommons.ursinus.edu/grizzlynews/1319/thumbnail.jp
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VITAMIN E: a multipurpose ENDF/B-V coupled neutron-gamma cross section library
The US Department of Energy Office of Fusion Energy and the Division of Reactor Research and Technology jointly sponsored the development of a coupled fine-group cross section library (VITAMIN-C). The experience gained in the generation, validation, and utilization of the VITAMIN-C library along with its broad range of applicability has led to the request for updating this data set using ENDF/B-V. Additional support in this regard has been provided by the Defense Nuclear Agency (DNA) and by EPRI in support of weapons analyses and light water reactor shielding and dosimetry problems, respectively. The rationale for developing the multipurpose ENDF/B-V-based VITAMIN-E library is presented, with special emphasis on new models used in the data generation algorithms. The library specifications and testing procedures are also discussed in detail. The distribution of the VITAMIN-E library is currently subject to the same restrictions as the distribution of the ENDF/B-V data. 2 tables
Left ventricular remodeling and hypertrophy in patients with aortic stenosis:insights from cardiovascular magnetic resonance
<p>Abstract</p> <p>Background</p> <p>Cardiovascular magnetic resonance (CMR) is the gold standard non-invasive method for determining left ventricular (LV) mass and volume but has not been used previously to characterise the LV remodeling response in aortic stenosis. We sought to investigate the degree and patterns of hypertrophy in aortic stenosis using CMR.</p> <p>Methods</p> <p>Patients with moderate or severe aortic stenosis, normal coronary arteries and no other significant valve lesions or cardiomyopathy were scanned by CMR with valve severity assessed by planimetry and velocity mapping. The extent and patterns of hypertrophy were investigated using measurements of the LV mass index, indexed LV volumes and the LV mass/volume ratio. Asymmetric forms of remodeling and hypertrophy were defined by a regional wall thickening <b>≥</b>13 mm and >1.5-fold the thickness of the opposing myocardial segment.</p> <p>Results</p> <p>Ninety-one patients (61±21 years; 57 male) with aortic stenosis (aortic valve area 0.93±0.32cm2) were recruited. The severity of aortic stenosis was unrelated to the degree (r<sup>2</sup>=0.012, P=0.43) and pattern (P=0.22) of hypertrophy. By univariate analysis, only male sex demonstrated an association with LV mass index (P=0.02). Six patterns of LV adaption were observed: normal ventricular geometry (n=11), concentric remodeling (n=11), asymmetric remodeling (n=11), concentric hypertrophy (n=34), asymmetric hypertrophy (n=14) and LV decompensation (n=10). Asymmetric patterns displayed considerable overlap in appearances (wall thickness 17±2mm) with hypertrophic cardiomyopathy.</p> <p>Conclusions</p> <p>We have demonstrated that in patients with moderate and severe aortic stenosis, the pattern of LV adaption and degree of hypertrophy do not closely correlate with the severity of valve narrowing and that asymmetric patterns of wall thickening are common.</p> <p>Trial registration</p> <p>ClinicalTrials.gov Reference Number: NCT00930735</p
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