the thesis has been arranged into five chapters and mainly concerned with the baer-invariant of groups which is the generalization of the schur-multiplier with respect to the variety of groups. chapter one is devoted to collect some notation and background information which are needed in the next chapters. its also contains some important statements which will be generalized in this thesis. cha...

in this thesis our aim is to construct vector field in r3 for which the corresponding one-dimensional maps have certain discontinuities. two kinds of vector fields are considered, the first the lorenz vector field, and the second originally introced here. the latter have chaotic behavior and motivate a class of one-parameter families of maps which have positive lyapunov exponents for an open in...

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 lexical knowledge of complex english words is an important part of language skills and crucial for fluent language use (nation, 2001). the present study, thus, was an attempt to assess the role of morphological decomposition awareness as a vocabulary learning strategy on learners’ productive and receptive recall and recognition of complex english words. so 90 sophomores (female and ma...

abstract this study set out to compare the effect of modality of presentation (subtitled vs. auditory) in the comprehension of verbal content of documentary films among iranian efl students. to this end, (30 male 30 female) students were chosen from two schools. after their homogeneity was established, the students attended the listening sessions to watch five documentary films over t...

vocabulary as a major component of language learning has been the object of numerous studies each of which has its own contribution to the field. finding the best way of learning the words deeply and extensively is the common objective of most of those studies. however, one effective way for achieving this goal is somehow neglected in the field. using a variety of activities such as games can r...

within communicative, interactive, and learner-centered framework of language teaching and learning, students need to learn four skills of listening, speaking, reading, and writing for their educational success. but of all the language skills, reading enjoys a paramount significance in so many second or foreign language academic contexts. in spite of its importance, language learners still have...

august wilson is undoubtedly one of the rare black playwrights whose works have attracted streams of attention and worldwide audience. the present study aims at analyzing fences and piano lesson which are two of the most successful plays in his pittsburgh cycle from the perspective of michel foucault’s theories and ideas. studying these two plays from foucault’s perspective opens new windows in...

a one dimensional dynamic model for a riser reactor in a fluidized bed catalytic cracking unit (fccu) for gasoil feed has been developed in two distinct conditions, one for industrial fccu and another for fccu using various frequencies of microwave energy spaced at the height of the riser reactor (fccu-mw). in addition, in order to increase the accuracy of component and bulk diffusion, instanta...

the following null hypothesis was proposed: h : there is no significant difference between the use of semantically or communicatively translates scientific texts. to test the null hypothesis, a number of procedures were taken first, two passages were selected form soyrcebooks of food and nutrition industry and gardening deciplines. each, in turn, was following by a number of comprehension quest...