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...

some researches made in the field of agency problem issue, deal with the role of control systems regarding owners and managers. in this research the relationship between the two control mechanisms, namely the voluntary disclosure (external control mechanism) and outside directors (internal control mechanism), which are reductive of agency problems, has been studied. for this reason, a sample ...

cement is an essential ingredient in the concrete buildings. for production of cement considerable amount of fossil fuel and electrical energy is consumed. on the other hand for generating one tone of portland cement, nearly one ton of carbon dioxide is released. it shows that 7 percent of the total released carbon dioxide in the world relates to the cement industry. considering ecological issu...

abstract chickpea is weak in competition of weeds that damages to it at between 40 t0 60 percent. kermanshah province is one of the most important region for chickpea fields in iran. for these reosons, weed management is necessary in this crop. in order to evaluate of herbicides and stubble control on broad leave weeds control in chickpea. experiment was conducted in agricultural research stat...

in civil engineering concrete is a material combined of hydraulic cement, sand, gravel and water. gravel and sand compose 60 to 70 percent of concrete. these aggregates support compression force of concrete. cement paste acts as glue to stick grain together. in bushehr factories producing aggregates do not operate according to astm standards, so that fineness modulus (fm) of the produced sands ...

the aim of the current study was to investigate the relationship among efl learners learning style preferences, use of language learning strategies, and autonomy. a total of 148 male and female learners, between the ages of 18 and 30, majoring in english literature and english translation at islamic azad university, central tehran were randomly selected. a package of three questionnaires was ad...

‏‎the community dynamics of aquatic coleoptera(insecta)in one of the spring-stream habitats of bammo national park in fars province called cheshmeh-ye-ghanbari is studied as a pilot project and model for acquaintance with and furthering the biodiversity studies on fauna of iran. sixteen species-populations out of nineteen of this community were already identified for their taxonomy and for thei...

abstract: proverbs are of the language materials which of the food of any language depends on the quality and quantity of these same materials. in the present research, the researcher tried to present the ramsarian proverbs according to four variables of color, fruit, plantsand animals that selected from the book of the members of each of these four variables, put them into the spss system fo...

abstract over the past two decades, applied linguists and language teachers have shown a great deal of interest in genre-centered approaches , mainly because of pedagogic concerns . this has been due to the need to help non-native readers enhance their ability to understand academic and scientific texts. following swales’ (1981) works on genre analysis, studies of different sections of resear...

abstract this study aimed at investigating the possible relationship between self-assessment in writing and self-regulation of iranian efl learners. the main purpose of the study was not only to report and inform about this relationship, but also to investigate and find practical outcomes of the incorporation of self-assessment in writing, such as improving writing skill. the research was carr...