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The goal in global illumination solutions for dynamic environments is to update a scene based on past scenes. For this difficult problem, current state of the art solutions are either not applicable, or unduly complex, when there are large changes in the illumination of unbounded number of objects. Such changes may be caused by the appearance of unexpected (at modeling time), irregular light sources.
We define a subset of dynamic environments in which new light sources may be user introduced, and implement solutions that complement existing schemes. 相似文献
3.
Mayur Sutaria Vinesh H. GadaAtul Sharma B. Ravi 《Journal of Materials Processing Technology》2012,212(6):1236-1249
The aim of the present work is to compute feed-paths and hot-spots by combining level-set-method based sharp interface and feed-path model. The model is based on the solution of energy and level-set equations in solid and liquid, with Stefan condition on the interface. The energy and level-set equation are discretized using finite-volume and finite-difference method, respectively. Feed-path is computed by tracking mass-less particles along the liquid-solid interface during solidification using combined Eulerian-Lagrangian framework. The proposed model is benchmarked on six test cases, where temperature contours and solidification time are compared with a finite-element-method based commercial software. The capability to predict the temporal evolution of interface and to identify multiple hot-spots is validated with an industrial aluminum-alloy lug casting. The numerical as well as experimental validations demonstrate the effectiveness of level-set-method for feed-path calculation. 相似文献
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Junye Wang Nicholas Christakis Mayur K. Patel Mark Cross Mark C. Leaper 《Numerical Heat Transfer, Part A: Applications》2013,63(8):751-776
As part of a comprehensive effort to predict the development of caking in granular materials, a mathematical model is introduced to model simultaneous heat and moisture transfer with phase change in porous media when undergoing temperature oscillations/cycling. The resulting model partial differential equations were solved using finite-volume procedures in the context of the PHYSICA framework and then applied to the analysis of sugar in storage. The influence of temperature on absorption/desorption and diffusion coefficients is coupled into the transport equations. The temperature profile, the depth of penetration of the temperature oscillation into the bulk solid, and the solids moisture content distribution were first calculated, and these proved to be in good agreement with experimental data. Then, the influence of temperature oscillation on absolute humidity, moisture concentration, and moisture migration for different parameters and boundary conditions was examined. As expected, the results show that moisture near boundary regions responds faster than farther away from them with surface temperature changes. The moisture absorption and desorption in materials occurs mainly near boundary regions (where interactions with the environment are more pronounced). Small amounts of solids moisture content, driven by both temperature and vapour concentration gradients, migrate between boundary and center with oscillating temperature. 相似文献
6.
Mayur Kenia 《世界电子元器件》2006,(8):24-26,36
引言
在蜂窝电话、PDA和便携式GPS等由电池供电的便携式产品中,高度集成的LT3491可为驱动背光照明电路组成简单和紧凑的解决方案。该器件具有内部补偿电路、LED开路保护功能、一个32V电源开关和一个32V肖特基二极管,而其封装却是纤巧的SC70。 相似文献
7.
The health effects of recreational gambling are presently unclear, particularly across age groups. Theories of healthy aging suggest that social activities, including gambling, may be beneficial to the health of older adults. Using cross-sectional data from the National Epidemiologic Survey on Alcohol and Related Conditions (N=43,093), the authors examined associations between gambling (categorized as nongambling, recreational gambling, or problem/pathological gambling) and health and functioning measures stratified by age (40-64 years and ≥65). Problem/pathological gambling was uniformly associated with poorer health measures among both younger and older adults. Among younger respondents, poorer health measures were also found among recreational gamblers. However, among older respondents, recreational gambling was associated not only with some negative measures (e.g., obesity) but also with some positive measures (e.g., better physical and mental functioning). Longitudinal studies are needed to clarify the relationship between gambling and health in older adults in the context of healthy aging. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
8.
Microalgae are promising biomass species owing to their fast growth rate and high CO2 fixation ability as compared to terrestrial plants. Microalgae have long been recognized as potentially good source for biofuel production because of their high oil content and rapid biomass production. In this study Chlorella sp. MP-1 biomass was examined for its physical and chemical characteristics using Bomb calorimeter, TGDTA, CHN and FTIR. The proximate composition was calculated using standard ASTM methodology. Chlorella sp. MP-1 biomass shows low ash (5.93%), whereas high energy (18.59 MJ/kg), carbohydrate (19.46%), and lipid (28.82%) content. The algal de-oiled cake was characterized by FTIR spectroscopy and thermogravimetric study at 10 °C/min and 30 °C/min to investigate its feasibility for thermo-chemical conversion. The present investigation suggests that within the realm of biomass energy technologies the algal biomass can be used as feedstock for bio and thermo-chemical whereas the de-oiled cake for thermo-chemical conversion thereby serving the demand of second generation biofuels. 相似文献
9.
Biodegradation of a mixture containing seven commercial textile dyes with different structures and color properties has been investigated by an ecofriendly strain--Brevibacillus laterosporus MTCC 2298. It showed 87% decolorization in terms of ADMI removal (American Dye Manufacturing Institute) within 24h. The effective decolorization of dye mixture was attained in the presence of metal salt--CaCl(2) and nitrogen sources. The induction of oxido-reductive enzymes such as veratryl alcohol oxidase, tyrosinase, NADH-DCIP reductase and azo reductase was found to be responsible for biotransformation of dyes. High performance thin layer chromatography exposed the mechanism of preferential biodegradation of dyes at different time periods. Significant change in the high pressure liquid chromatography and Fourier transform infrared spectroscopy of sample before and after treatment confirmed the biodegradation of dye mixture. Phytotoxicity study revealed the much less toxic nature of the metabolites produced after the degradation of dyes mixture. 相似文献
10.
PM Sutaria M Ohebshalom TA McCaffrey ED Vaughan D Felsen 《Canadian Metallurgical Quarterly》1998,62(21):1965-1972
Transforming growth factor-beta (TGF-beta) is a profibrotic cytokine which has been implicated in the renal fibrosis which follows unilateral ureteral obstruction (UUO) in the rat. TGF-beta receptor type I (TGF-RI) and TGF-beta receptor type II (TGF-RII) are part of the complex which mediates the response to TGF-beta. We sought to determine if TGF-RI and TGF-RII are found in the kidney, and if their expression is changed as a result of UUO. Polymerase chain reaction (PCR) was used to determine expression of mRNA for TGF-RI and TGF-RII in the kidney. Immunoperoxidase was used to localize and quantify the expression of these receptors at 3, 7, 14, 21 and 28 days after UUO, and in sham-operated animals. Expression of mRNA for TGF-RI and TGF-RII was demonstrated in sham operated, obstructed and contralateral unobstructed kidneys using PCR. Using immunoperoxidase, a uniform distribution of TGF-RI and TGF-RII was found in cortical tubules of sham operated kidneys, whereas medullary tubules showed a patchy TGF-RI distribution and no TGF-RII staining. After UUO, an increased tubular expression of TGF-RI and TGF-RII was noted in both obstructed and contralateral kidneys compared to sham operated kidneys. No staining for either TGF-RI or TGF-RII was noted in glomeruli, vasculature or interstitial cells. TGF-beta receptors I and II were found exclusively in renal tubules and were shown to increase in both the obstructed and contralateral kidneys relative to sham operated animals. Upregulation of TGF-beta receptors in both kidneys suggests that TGF-beta may contribute to the fibrotic response in the obstructed kidney and the hypertrophic response of the contralateral kidney. 相似文献