attempts have been made to study the thermodynamic behavior of 1,3 butadiene purification columns with the aim of retrofitting those columns to more energy efficient separation schemes. 1,3 butadiene is purified in two columns in series through being separated from methyl acetylene and 1,2 butadiene in the first and second column respectively. comparisons have been made among different therm...

abstract this paper discusses several commonly used models for strategic marketing¹ including market environmental analysis methods (i.e. swot and pest analysis) and strategic marketing tools and techniques (i.e. boston matrix and shell directional policy matrix)and shows how these models may help a firm to achieve its strategic goals. at first, the main reason for doing this research is de...

Software system verification is an efficient technique for ensuring the correctness of a software product, especially in safety-critical systems in which a small bug may have disastrous consequences. The goal of software verification is to ensure that the product fulfills the requirements. Studies show that the cost of finding and fixing errors in design time is less than finding and fixing the...

    The number of factors affecting total factor productivity has been increasing far from those which considered in growth models. So, institutional factors have been attracting strong attention of researchers. This paper aims at investigating the effects of these institutional factors together with traditional factors on TFP growth during 1971-2007.   For this purpose, we present a State-Spac...

rivers and runoff have always been of interest to human beings. in order to make use of the proper water resources, human societies, industrial and agricultural centers, etc. have usually been established near rivers. as the time goes on, these societies developed, and therefore water resources were extracted more and more. consequently, conditions of water quality of the rivers experienced rap...

 In various statistical mechanical models, introduction of a metric into space of prameters gives a new perspective to the phase structure. In this paper, the scalar curvature R of this metric for a one dimensional four-state complex spin model is calculated. It is shown that this parameter has a similar behaviour to the Ising and Potts models.