Modeling Flame Propagation of Coal Char Particles in Heterogeneous Media

In the present research, combustion of a quiescent coal char particle cloud has been studied in the media with spatially discrete sources by means of numerical approach. A thermal model based on diffusion-controlled regime of coal char particles has been generated in order to estimate the characteristics of flame propagation in heterogeneous media. The model uses discrete heat sources to analyze dust combustion of particles with the diameter of 50 μm. Oxygen and Nitrogen have been considered as the main oxidizer and the inert gas, respectively. Flame propagation speed in various dust and oxygen concentrations has been studied. Flame speed as a function of particle size has been investigated and comparison between cases with and without consideration of radiation effect has been made. Furthermore, minimum ignition energy as a function of dust concentration for different particle sizes has been studied. Results show a reasonable compatibility with the existing experimental data

Variation of DAT1 VNTR alleles and genotypes among old ethnic groups in Mesopotamia to the Oxus region

Variation of a VNTR in the DAT1 gene in seven ethnic groups of the Middle East was used to infer the history and affinities of these groups. The populations consisted of Assyrian, Jewish, Zoroastrian, Armenian, Turkmen, and Arab peoples of Iran, Iraq, and Kuwait. Three hundred forty subjects from these seven ethnic groups were screened for DAT1. DAT1 VNTR genotyping showed 3, 6, 7, 8, 9, 10, 11, and 12 alleles in the samples. Analysis of these data revealed differentiation and relationship among the populations. In this region, which covers an area of 2-2.5 million km2, the influence of geography and especially of linguistic characteristics has had potentially major effects on differentiation. Religion also has played a major role in imposing restrictions on some ethnic groups, who as a consequence have maintained their community. Overall, these ethnic groups showed greater heterogeneity compared to other populations. Copyright © 2008 Wayne State University Press

International relations in the making of political Islam: interrogating Khomeini's ‘Islamic government’

Eurocentric approaches to political Islam tend to deploy an internalist methodology that theoretically obscures the generative and constitutive role of international relations. This article addresses this problem through a critical application of Leon Trotsky's idea of ‘uneven and combined development’ to Ayatollah Khomeini's invention of the concept of ‘Islamic government’. It argues that this concept was international in its socio-political stimulus and intellectual content, and, crucially, reflected, influenced, and mobilised an emergent liminal sociality that combined Western and Islamic socio-cultural forms. This heterogeneous character of Iran's experience of modernity is, the article argues, theoretically inaccessible to Eurocentric approaches’ homogeneous and unilinear conceptions of history, which, as a result, generate exceptionalist modes of explanations