210,969 research outputs found
Large-eddy simulation of dispersion from surface sources in arrays of obstacles
Full text linkTowards meeting the objective of simulating heat transfer processes in urban areas, the study of dispersion from a scalar (ground) surface area source has been addressed as a first step, as dispersion from such a source is in some ways analogous to heat transfer from the surface. Two different urban-like geometries are considered in this study: an array with uniform height cubes and an array with random height cuboids. Some point measurement dispersion experiments in a wind tunnel have previously been carried out in identical arrays using a naphthalene sublimation technique. Large-eddy simulations (LES) of these experiments have been performed as a validation study and the details, presented here, demonstrate the influence of the roughness morphology on the dispersion processes and the power of LES for obtaining physically important scalar turbulent flux information
Large-eddy simulation for flow and dispersion in urban streets
No full textLarge-eddy simulations (LES) with our recently developed inflow approach (Xie &Castro, 2008a) have been used for flow and dispersion within a genuine city area -the DAPPLE site, located at the intersection of Marylebone Rd and Gloucester Plin Central London. Numerical results up to second-order statistics are reported fora computational domain of 1.2km (streamwise) x 0.8km (lateral) x 0.2km (in fullscale), with a resolution down to approximately one meter in space and one secondin time. They are in reasonable agreement with the experimental data. Such a comprehensiveurban geometry is often, as here, composed of staggered, aligned, squarearrays of blocks with non-uniform height and non-uniform base, street canyons andintersections. Both the integrative and local effect of flow and dispersion to thesegeometrical patterns were investigated. For example, it was found that the peaksof spatially averaged urms, vrms, wrms and < u0w0 > occurred neither at the meanheight nor at the maximum height, but at the height of large and tall buildings. Itwas also found that the mean and fluctuating concentrations in the near-source fieldis highly dependent on the source location and the local geometry pattern, whereasin the far field (e.g. >0.1km) they are not. In summary, it is demonstrated thatfull-scale resolution of around one meter is sufficient to yield accurate prediction ofthe flow and mean dispersion characteristics and to provide reasonable estimationof concentration fluctuation
R. Latouche, Les origines de l'économie occidentale (IVe-XIe siècle)
No full textDoehaerd Renée. R. Latouche, Les origines de l'économie occidentale (IVe-XIe siècle). In: Annales. Economies, sociétés, civilisations. 13ᵉ année, N. 2, 1958. pp. 389-393
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Systolederus heishidingensis Zheng & Xie 2004
No full text12. Systolederus heishidingensis Zheng & Xie, 2004 Systolederus heishidingensis Zheng & Xie, 2004, Journal of Shaanxi Normal University. 32(3): 83. Specimens examined: P. R. CHINA: 1♀, Guangdong: Fengkai, 2002-VIII-18. Distribution: P. R. CHINA: Guangdong.Published as part of Deng, Wei-An, Lu, Xiang-Yi, Zhao, Cong-Lin & Wu, Fei-Peng, 2019, A review of the genus Systolederus Bolivar (Orthoptera: Metrodorinae) from China, pp. 489-500 in Zootaxa 4585 (3) on page 497, DOI: 10.11646/zootaxa.4585.3.5, http://zenodo.org/record/264021
"Closing the R&D Gap, Evaluating the Sources of R&D Spending"
Full text linkBoth spending and tax policies have been implemented in the United States with the goal of stimulating private sector research and development (R&D). Karier questions whether current R&D policy, especially the research and experimentation tax credit, can contribute to closing the gap between nondefense expenditures on R&D in the United States and such expenditures in other countries, such as Japan and Germany. He also explores possible changes to our current R&D policy to make it more effective.
A redescription of Piguetiella denticulata Liang and, Xie (Oligochaeta, Tubificidae, Naidinae) from China, with a key to the genus Piguetiella
No full textPiguetiella denticulata Liang & Xie, 1997 is redescribed based on the type series collected from the type locality, Songtao River, and streams of the Zhangjiajie Mountain in southwestern China, and specimens from several tributaries of the Yangtze River. This species is characterized by a large body size, the absence of eyespots and dorsal hair chaetae, the same size and shape of dorsal and ventral chaetae, the presence of 3-4 intermediate teeth on both ventral and dorsal chaetae, and an intestinal dilation in IX-X segments. The essential characteristics used to diagnose the genus are discussed and a key to the genus is provided.Piguetiella denticulata Liang & Xie, 1997 is redescribed based on the type series collected from the type locality, Songtao River, and streams of the Zhangjiajie Mountain in southwestern China, and specimens from several tributaries of the Yangtze River. This species is characterized by a large body size, the absence of eyespots and dorsal hair chaetae, the same size and shape of dorsal and ventral chaetae, the presence of 3-4 intermediate teeth on both ventral and dorsal chaetae, and an intestinal dilation in IX-X segments. The essential characteristics used to diagnose the genus are discussed and a key to the genus is provided
Criotettix brevipennis Zheng & Xie 2002
No full text38. Criotettix brevipennis Zheng & Xie, 2002 Criotettix brevipennis Zheng & Xie, 2002, Entomologica Sinica, 45 suppl. 7–8. figs. 4–7. Specimens examined: P. R. CHINA: 1♂ 2♀, Guangxi: Baise, 1999-IX-23; 1♂ 1♀, Yunnan: Shizong, 2006-VIII-05. Distribution: P. R. CHINA: Guangxi and Yunnan.Published as part of Deng, Wei-An, Chen, Dan-Ni, Sheng, Qin, Zhao, Cong-Lin & Wu, Fei-Peng, 2019, An annotated catalogue of the pygmy grasshoppers of the genus Criotettix Bolívar 1887 (Orthoptera: Tetrigidae) with two new Criotettix species from China, pp. 498-518 in Zootaxa 4629 (4) on page 514, DOI: 10.11646/zootaxa.4629.4.2, http://zenodo.org/record/327409
Latouche (R.) — Textes d'histoire médiévale, Ve-XIe siècles, (Publ. Fac. Lettres Grenoble, n° 2) 1951
No full textMollat Michel. Latouche (R.) — Textes d'histoire médiévale, Ve-XIe siècles, (Publ. Fac. Lettres Grenoble, n° 2) 1951. In: Revue du Nord, tome 34, n°136, Octobre-décembre 1952. p. 263
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