661 research outputs found
DEVELOPMENT OF THE ALTERNATE PRESSURIZED THERMAL SHOCK RULE (10 CFR 50.61a) IN THE UNITED STATES
In the early 1980s, attention focused on the possibility that pressurized thermal shock (PTS) events could challenge the integrity of a nuclear reactor pressure vessel (RPV) because operational experience suggested that overcooling events, while not common, did occur, and because the results of in-reactor materials surveillance programs showed that RPV steels and welds, particularly those having high copper content, experience a loss of toughness with time due to neutron irradiation embrittlement. These recognitions motivated analysis of PTS and the development of toughness limits for safe operation. It is now widely recognized that state of knowledge and data limitations from this time necessitated conservative treatment of several key parameters and models used in the probabilistic calculations that provided the technical of the PTS Rule, 10 CFR 50.61. To remove the unnecessary burden imposed by these conservatisms, and to improve the NRC's efficiency in processing exemption and license exemption requests, the NRC undertook the PTS re-evaluation project. This paper provides a synopsis of the results of that project, and the resulting Alternate PTS rule, 10 CFR 50.61a
Relative compactness, cotopology and some other notions from the bitopological point of view
AbstractThe paper consists of two sections. Section 1 is the introduction which, in addition to the auxiliary information, contains some interesting results on Baire-like properties. Section 2 deals with the bitopological essence of the notions of relative compactness and cotopology in general topology, C-relation, subordination of topologies and closed neighborhoods condition in analysis. A generalization of Choquet's theorem on Baire spaces is given and the sufficient conditions for families of (i,j)-nowhere dense sets to coincide with families of (i,j)-first category sets are established using a finite measure. A bitopological solution of one of Ulam's problems is obtained. The corresponding relations are almost always studied using essentially the bitopological modifications of regularity, which, as seen in various problems of general topology, analysis and potential theory, are the most natural forms of relations of two topologies defined on the same set
How Geography and International Relations Shaped Economic Development in the Republic of Korea
Joan, PerePrimer pla contrapicat del relleu de sant
Jordi que forma part de la decoració de
la façana gòtica del Palau de la Generalitat. Apreciem el cavaller muntant el cavall i el drac.
Fet en pedra de Montjuïc
In This Issue
Ventura Rodríguez, Ferran (escultor)Pla general d'una part del Fossar. Era Era una antiga pedrera
que va es va destinar a enterrar víctimes
dels bombardeigs de la guerra civil, de les
execucions de la guerra i l'època
franquista. A partir del 1979 passar a ser
un memorial
Test Characteristics of Urinary Lipoarabinomannan and Predictors of Mortality among Hospitalized HIV-Infected Tuberculosis Suspects in Tanzania.
Tuberculosis is the most common cause of death among patients with HIV infection living in tuberculosis endemic countries, but many cases are not diagnosed pre-mortem. We assessed the test characteristics of urinary lipoarabinomannan (LAM) and predictors of mortality among HIV-associated tuberculosis suspects in Tanzania. We prospectively enrolled hospitalized HIV-infected patients in Dar es Salaam, with ≥2 weeks of cough or fever, or weight loss. Subjects gave 2 mLs of urine to test for LAM using a commercially available ELISA, ≥2 sputum specimens for concentrated AFB smear and solid media culture, and 40 mLs of blood for culture. Among 212 evaluable subjects, 143 (68%) were female; mean age was 36 years; and the median CD4 count 86 cells/mm(3). 69 subjects (33%) had culture confirmation of tuberculosis and 65 (31%) were LAM positive. For 69 cases of sputum or blood culture-confirmed tuberculosis, LAM sensitivity was 65% and specificity 86% compared to 36% and 98% for sputum smear. LAM test characteristics were not different in patients with bacteremia but showed higher sensitivity and lower specificity with decreasing CD4 cell count. Two month mortality was 64 (53%) of 121 with outcomes available. In multivariate analysis there was significant association of mortality with absence of anti-retroviral therapy (p = 0.004) and a trend toward association with a positive urine LAM (p = 0.16). Among culture-negative patients mortality was 9 (75%) of 12 in LAM positive patients and 27 (38%) of 71 in LAM negative patients (p = 0.02). Urine LAM is more sensitive than sputum smear and has utility for the rapid diagnosis of culture-confirmed tuberculosis in this high-risk population. Mortality data raise the possibility that urine LAM may also be a marker for culture-negative tuberculosis
Shear induced instabilities in layered liquids
Motivated by the experimentally observed shear-induced destabilization and
reorientation of smectic A like systems, we consider an extended formulation of
smectic A hydrodynamics. We include both, the smectic layering (via the layer
displacement u and the layer normal p) and the director n of the underlying
nematic order in our macroscopic hydrodynamic description and allow both
directions to differ in non equilibrium situations. In an homeotropically
aligned sample the nematic director does couple to an applied simple shear,
whereas the smectic layering stays unchanged. This difference leads to a finite
(but usually small) angle between n and p, which we find to be equivalent to an
effective dilatation of the layers. This effective dilatation leads, above a
certain threshold, to an undulation instability of the layers. We generalize
our earlier approach [Rheol. Acta, vol.39(3), 15] and include the cross
couplings with the velocity field and the order parameters for orientational
and positional order and show how the order parameters interact with the
undulation instability. We explore the influence of various material parameters
on the instability. Comparing our results to recent experiments and molecular
dynamic simulations, we find a good qualitative agreement.Comment: 15 pages, 12 figures, accepted for publication in PR
Nature of Viscoelasticity in Lamellar Block Copolymers: Contraction Correlated to Strain Localization
We determined the local strain profile in sheared lamellar block copolymers. A trilayer model, based on elastic brushes separated by viscous interpenetration zones, captures the rheological response of these materials and provides a measure of the relative contributions of elastic versus viscous strain. The elastic chain distortions were evident from a reversible lamellar contraction, as measured from in situ small-angle x-ray scattering. The contraction was directly correlated to the elastic strain from our trilayer model; three distinct diblock copolymers conform to the predicted relationship, thus suggesting universal behavior
Environmental risk assessment studies on new plant protection products which have been elaborated from coniferous tree bark
ArticleNowadays there are still various chemical pesticides being applied in the course of ensuring plant protection. Since 2010, we have been working on the development of new, environmentally-friendly plant protection products which will provide an effective tool against pathogenic fungi and bacteria which cause disease in crop plants. The specific aim of this study was to evaluate a risk assessment for new plant protection products that have been elaborated on the basis of coniferous tree bark. Various products were tested which are extracted during the processing of wood bark from pine (Pinus sylvestris L.) and spruce (Picea abies (L.) Karst.). Ethanol extracts were formulated and applied during these experiments. Two formulations, which showed anti-fungal activity in vitro and in field trials on fruit crops (involving strawberries and raspberries) were selected for the risk assessment studies. The impact was studied of formulation treatment on crop plants and soil biological activity, and the accumulation of residues of active substances in crop plants and soil. The application of new formulations did not show any negative effect on the chlorophyll content and the chlorophyll fluorescence of plant leaves. The results showed that pine and spruce bark extract formulations contain active compounds (coumaric acid, quercetin, epicatechin, and ferulic acid) within the range of 5.1–5.9 mg kg-1 and 11.1– 443.9 mg kg-1 respectively. The amount of active substances which were determined in most cases was higher in the spruce bark extract formulation when compared to the pine bark extract formulation. Our results confirmed the presence of active compounds – epicatechin, quercetin, and coumaric acid – in strawberry fruits which remained untreated and in those that were treated with spruce ethanol extract formulation. Untreated raspberry fruits contained all four active substances within the range of 81–5,300 µg kg-1. We observed a significant increase of coumaric acid and quercetin in raspberries after their having been treated with spruce bark extract formulation in a 2% concentration, P < 0.05, and did not find any negative impact for spruce bark extract formulations when used on soil microbial biomass
Long-term species, sexual and individual variations in foraging strategies of fur seals revealed by stable isotopes in whiskers
Background: Individual variations in the use of the species niche are an important component of diversity in trophic interactions. A challenge in testing consistency of individual foraging strategy is the repeated collection of information on the same individuals. Methodology/Principal Findings: The foraging strategies of sympatric fur seals (Arctocephalus gazella and A. tropicalis) were examined using the stable isotope signature of serially sampled whiskers. Most whiskers exhibited synchronous delta C-13 and delta N-15 oscillations that correspond to the seal annual movements over the long term (up to 8 years). delta C-13 and delta N-15 values were spread over large ranges, with differences between species, sexes and individuals. The main segregating mechanism operates at the spatial scale. Most seals favored foraging in subantarctic waters (where the Crozet Islands are located) where they fed on myctophids. However, A. gazella dispersed in the Antarctic Zone and A. tropicalis more in the subtropics. Gender differences in annual time budget shape the seal movements. Males that do not perform any parental care exhibited large isotopic oscillations reflecting broad annual migrations, while isotopic values of females confined to a limited foraging range during lactation exhibited smaller changes. Limited inter-individual isotopic variations occurred in female seals and in male A. tropicalis. In contrast, male A. gazella showed large inter-individual variations, with some males migrating repeatedly to high-Antarctic waters where they fed on krill, thus meaning that individual specialization occurred over years. Conclusions/Significance: Whisker isotopic signature yields unique long-term information on individual behaviour that integrates the spatial, trophic and temporal dimensions of the ecological niche. The method allows depicting the entire realized niche of the species, including some of its less well-known components such as age-, sex-, individual- and migration-related changes. It highlights intrapopulation heterogeneity in foraging strategies that could have important implications for likely demographic responses to environmental variability
Measurement and comparison of individual external doses of high-school students living in Japan, France, Poland and Belarus -- the "D-shuttle" project --
Twelve high schools in Japan (of which six are in Fukushima Prefecture), four
in France, eight in Poland and two in Belarus cooperated in the measurement and
comparison of individual external doses in 2014. In total 216 high-school
students and teachers participated in the study. Each participant wore an
electronic personal dosimeter "D-shuttle" for two weeks, and kept a journal of
his/her whereabouts and activities. The distributions of annual external doses
estimated for each region overlap with each other, demonstrating that the
personal external individual doses in locations where residence is currently
allowed in Fukushima Prefecture and in Belarus are well within the range of
estimated annual doses due to the background radiation level of other
regions/countries
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