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61.
Size distributions of starch granules can be determined by microscopes, sieves, sedimentation methods, and Coulter Counter. Data obtained form discontinuous relative or cumulative expressions of weight or number distributed according to particle diameter or volume. Using a hypothetical example, the permitted transformations of data are described as a basis for comparison of results by several analytical methods. The definition of bimodality of size distribution and the precision of distributive analyses are briefly considered. 相似文献
62.
In many applications where battery powered drives are used, high efficiency, low cost, and low weight are of prime importance. Such applications include electric vehicles, fork-lift trucks, submarines, etc. 相似文献
63.
We study a scheduling problem to minimise total late work, i.e. each job is penalised according to the duration of its parts scheduled after its due-date. The machine setting is an m-machine proportionate flow shop. Two versions of the problem are studied: (i) the case that total late work refers to the last operation of the job (i.e. the operation performed on the last machine of the flow shop); (ii) the case that total late work refers to all the operations (on all machines). Both versions are known to be NP-hard. We prove a crucial property of an optimal schedule, and consequently introduce efficient pseudo-polynomial dynamic programming algorithms for the two versions. The dynamic programming algorithms are tested numerically and proved to perform well on large size instances. 相似文献
64.
Urbanization brings several changes to the natural environment. First, vegetation is supressed and natural scenery is modified, in order to accommodate manmade buildings and streets. Consequences bring a direct effect on fauna and flora and, due to a modified environment, with heat fluxes having a different pattern from that of the original site, on climatic features, such as on air temperature and humidity, radiative and convective heat exchanges. Thus, one of the factors that can contribute directly to the creation of urban climate is land use. The present study investigates how land use influences local temperatures in Curitiba, Brazil (25°31′S, 917 m elevation). For that purpose, seven different locations of the city were analyzed during a 1-month period by monitoring air temperature and humidity. Also, land use patterns around each location were quantified, according to five different categories established for that purpose: water area, built area, free area, paved area and green area. The monitoring of climatic data occurred in winter (June/July) of 2002. Comparisons were made regarding averages of the minimum, average and maximum temperatures for each location, qualitatively and quantitatively. As a final step of this study, formulas were developed expressing the local temperatures as a function of air temperatures, solar radiation and the wind speed of the meteorological station, which was used as reference station. 相似文献
65.
The preparation of high quality polypyrrole film in aqueous solutions is described. The new polypyrrole films were produced in a phthalate buffer solution (pH 4) with perchlorate as the electrolyte. Very smooth and remarkably flexible free-standing films were grown electrochemically. The conductivity of the polypyrrole film exhibits an inverse dependency on the film thickness. The mechanical properties of these films, such as tensile strength and the modulus of elasticity, are better than the reported properties for polypyrrole/tosylate films prepared in organic solutions. In comparison with the polypyrrole films prepared in phosphate buffer solution, the stability of the polypyrrole films prepared in phthalate buffer are improved considerably. The morphology and composition of the conducting film is described and a mechanism for their formation is proposed. 相似文献
66.
In this article we examine some of the basic psychophysics relevant to amplified night vision devices. These devices produce images that are substantially different from ordinary visual scenes. Distortions in contrast and luminance and the introduction of visual interference and geometrical artifacts contribute to unusual viewing conditions. We carried out experiments to determine the effect of these parameters of the image on a highly controlled visual target detection task simulated on a computer graphics system that closely models a night vision device. Our results indicate that display luminance and geometrical artifacts degrade detection performance only slightly, whereas contrast and visual interference have a substantial degrading effect. 相似文献
67.
Kretsch Rina; Benyakar Mordechai; Baruch Eli; Roth Merav 《Canadian Metallurgical Quarterly》1997,34(1):28
Utilizes the example of the Gulf War to present a conceptualization and a pragmatic model of professional intervention during situations of national crisis, like the recent situations (bomb explosions) in Buenos Aires, Argentina and in Oklahoma City, US. The authors discuss the impact of the shared reality experienced by therapists and patients, when both are exposed to a national crisis. The article stresses the importance of going out into the field and aiding the victims wherever they are. It describes interventions by an Israeli mental health team formed during the Gulf War, which assisted victims, whose homes were damaged by Scud missiles, wherever they were housed after their evacuation. By addressing the questions that confront the therapist in a national crisis of this kind, the authors introduced a certain mode of work that reflects the way the therapist and the patient cope with their shared reality as well as with the interrelationship between external organization and internal mobilization. Three case examples of adult individuals whose homes were destroyed during the war serve to illustrate the effectiveness of the technique of immediate intervention in the field in a crisis of this kind. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
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Oil dispersants, the tool of choice for treating oil spills in tropical marine environments, is potentially harmful to marine life, including reef corals. In a previous study, we found that dispersed oil and oil dispersants are harmful to soft and hard coral species at early life stages. In this broader study, we employed a "nubbin assay" on more than 10 000 coral fragments to evaluate the short- and long-term impacts of dispersed oil fractions (DOFs) from six commercial dispersants, the dispersants and water-soluble-fractions (WSFs) of Egyptian crude oil, on two Indo Pacific branching coral species, Stylophora pistillata and Pocillopora damicornis. Survivorship and growth of nubbins were recorded for up to 50 days following a single, short (24 h) exposure to toxicants in various concentrations. Manufacturer-recommended dispersant concentrations proved to be highly toxic and resulted in mortality for all nubbins. The dispersed oil and the dispersants were significantly more toxic than crude oil WSFs. As corals are particularly susceptible to oil detergents and dispersed oil, the results of these assays rules out the use of any oil dispersant in coral reefs and in their vicinity. The ecotoxicological impacts of the various dispersants on the corals could be rated on a scale from the least to the most harmful agent, as follows: Slickgone > Petrotech > Inipol = Biorieco > Emulgal > Dispolen. 相似文献