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Construction and demolition waste production and management in developing countries (a case study: Tehran metropolitan, Iran)
, Article Annual Conference of the Canadian Society for Civil Engineering 2007: Where the Road Ends, Ingenuity Begins, Yellowknife, NT, 6 June 2007 through 9 June 2007 ; Volume 2 , 2007 , Pages 1121-1130 ; Kavousiar, A ; Sharif University of Technology
2007
Abstract
Construction industry is one of the most important fractions of economy in developing countries. This industry consumes enormous amounts of raw materials and produces considerable waste. The optimization of construction material usage not only saves costs but also can significantly contribute towards Sustainable Development. This article addresses Construction Waste Management as an approach to improve construction productivity, with a focus on its application in developing countries. The status of construction waste production and management in Tehran metropolitan, Iran-as a developing country-is investigated and compared with the status of developed countries. Subsequently, barriers to...
Carbon dioxide: A waste product in the catalytic cycle of α-ketoglutarate dependent halogenases prevents the formation of hydroxylated by-products
, Article Journal of Physical Chemistry B ; Volume 113, Issue 1 , 2009 , Pages 12-14 ; 15206106 (ISSN) ; Latifi, R ; Sharif University of Technology
American Chemical Society
2009
Abstract
We present the first density functional theory study on α-ketoglutarate dependent halogenase and focus on the mechanism starting from the iron(IV)-oxo species. The studies show that the high-valent iron(IV)-oxo species reacts with substrates via an initial and rate determining hydrogen abstraction that is characterized by a large kinetic isotope effect (KIE) of 26.7 leading to a radical intermediate. This KIE value is in good agreement with experimental data. The reaction proceeds via two-state reactivity patterns on competing quintet and septet spin state surfaces with close lying hydrogen abstraction barriers. However the septet spin radical intermediate gives very high barriers for...