نتایج جستجو برای: concentrated source and source over circular region
تعداد نتایج: 17021504 فیلتر نتایج به سال:
There are several different definitions and kinds of case studies. Because of different reasons the case studies can be either single or multiple. This study attempts to answer when to write a single case study and when to write a multiple case study. It will further answer the benefits and disadvantages with the different types. The literature review, which is based on secondary sources, is ab...
The design method and fabrication of mirrors with variable reflectivity are presented. To fabricate such a mirror a fixed mask with a circular aperture is used. The circular aperture is considered as an extended source with cosx(θ)as its diffusion distribution function and is the parameter for the distribution function of the particles through the aperture. The thickness profile of deposited ...
Crude oils and source rocks from the Northern and offshore depobelts of the Niger Delta basin, Nigeria have been characterized based on the distribution of pyrene and its derivatives by gas chromatography-mass spectrometry. Moreover, the crude oils have been characterized by the dominance of pyrene over fluoranthene while fluoranthene generally predominated over pyrene in the rock samples. Also...
In friction stir welding frictional heat is generated by the rotating tool, sliding over the stationary plate along the weld centre. Tool being the only source of heat producing member, its geometrical design influences the heat generation rate. In this present work, effects of variation in tool shoulder and tool pin taper angles on thermal history during joining are analysed. Tools with triang...
there are two major theories of measurement in psychometrics: classical test theory (ctt) and item-response theory (irt). despite its widespread and long use, ctt has a number of shortcomings, which make it problematic to be used for practical and theoretical purposes. irt tries to solve these shortcomings, and provide better and more dependable answers. one of the applications of irt is the as...
Crude oils and source rocks from the northern and offshore Niger Delta basin, Nigeria, have been characterized by gas chromatography-mass spectrometry in terms of their origin and thermal maturity based on the distribution of chrysene and its derivatives. The crude oils and source rocks were characterized by the dominance of chrysene over benzo[a]anthracene. 3-methylchrysene predominated over o...
Different approaches of source apportionment of dust fractions have been reported world-over. Predicting source categories within receptor chemical profiles using regression and factor analysis using PCA has been reported to evaluate possible source/routes of air pollution mass. The present study is focused on the application of all three approaches to investigate higher degrees of significance...
Background: Due to the lack of a proper waste management system, Tehran Municipality Region 20 is facing economic and environmental problems such as the high costs of a disposal system and source pollution. Life cycle assessment (LCA) is a method for collecting and evaluating the inputs, outputs, and potential environmental impacts of a product system throughout its life cycle. The current stud...
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