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...

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...

boron nitride semiconducting zigzag swcnt, $b_{cb}$$n_{cn}$$c_{1-cb-cn}$, as a potential candidate for making nanoelectronic devices was examined. in contrast to the previous dft calculations, wherein just one boron and nitrogen doping configuration have been considered, here for the average over all possible configurations, density of states (dos) was calculated in terms of boron and nitrogen ...

writing as a productive skill requires practice in the basic sub-skills of vocabulary and grammar. in fact, grammar has been viewed as the core of programs in writing classes to help the students put the elements of sentence together and combine sentences of specific lengths to come up with an error-free work of art. conceptualizing l2 writing in this way introduces writing as a product and enc...

abstract following innovations in the field of elt, a new topic which has recently attracted a lot of attention is metaphor analysis. although this area of research is still in its infancy in elt, it seems that the idea can shed more light on the puzzle of english language learning and teaching. therefore, the major aim of this study is to analyze language learning and teaching in formal a...

adolescents and young adults and their problems is an issue whose importance is obvious to anyone because youth are the founders of our countrys future and requires proper planning to be on leisure. given the importance of leisure,this study to investigate needs assessment and planning how adolescents and young adults spend their leisure time in urban of case study of high school girls and boys...

the present study sought to examine whether a task-based approach could have an impact on raising awareness of collocations. moreover, it sought to investigate the facilitative role of consciousness-raising tasks of collocations in the communicative instances of use. to this end, 68 intermediate learners of english were selected via a placement test. the participants were taught with classroom ...

we commence by using from a new norm on l1(g) the -algebra of all integrable functions on locally compact group g, to make the c-algebra c(g). consequently, we find its dual b(g), which is a banach algebra so-called fourier-stieltjes algebra, in the set of all continuous functions on g. we consider most of important basic theorems about this algebra. this consideration leads to a rather com...

the ability to speak two languages in the world is a remarkable achievement. there is a good reason to believe that bilingualism is the norm for the majority of people in the world because 70% of the earth’s population are supposed to be bilingual or multilingual. various investigations have shown that the native language impacts foreign word recognition, and this influence is adapted by the de...

we have two part in this thesis, at first: the interaction of native calf thymus dna (ct-dna) with two anthraquinones including quinizarin (1,4- dihydroxy anthraquinone) and danthron (1,8- dihydroxy anthraquinone) in a mixture of 0.04 m brittone-robinson buffer and 50% of ethanol were studied at physiological ph by uv-vis absorption, florescence, circular dichroism spectroscopic methods, viscos...