Introduction: Polycyclic Aromatic Hydrocarbons (PAHs) belong to one of the groups of persistent organic pollutants (POPs) which are the result of incomplete combustion of organic materials, volcanic eruptions and forest and agricultural fields’ fires in the environment. However, human factors are main source of these pollutions. Nowadays, these compounds are among the main concerns related to t...

the purpose of this study is to investigate the relationships between teachers’ immediacy behaviors and iranian students’ willingness to talk in english classes. analysis of the results from willingness to talk scale represents a relatively high level of willingness to talk in english classrooms among iranian language learners. the total mean score of students’ willingness to talk was 66.3 ou...

Composite solid propellants are materials that constitute from an oxidizer, an organic binder, a metallic fuel, additives and etc. Nowadays the size of energetic particles is attended because of their functional profits. Size reduction is well known way to increasing reactivity of additives in propellant formulations. Nanoparicles have considerable effects on composite solid propellants propert...

Regarding to the increase of cost and consumption of the nonrenewable energies such as natural gas and electricity, using renewable energies such as solar energy reduces the consumption of nonrenewable energies. In this research, at first, a regenerative organic Rankine cycle with flat plate solar collector as energy source is simulated and the effects of different parameters such as turbine in...

abstract abstract of thesis (includes summary, goals, execution methods, and results) story “al-obnosat al-bayza” is one of the short stories from “hanna mineh” collection. this story is a selection of lives of some humans during a voyage together, each of them is a symbol of human nature (love, mind, kindness) and examine social, cultural, and political aspects of governing system, and it...

مراتع حدود نیمی از خشکی های جهان را در بر دارند و پوشش گیاهی آن در نتیجه تأثیر متقابل محیط و موجودات زنده به وجود آمده است و به عنوان یک اکوسیستم طبیعی مدیریت می شوند. علاوه بر مراتع، راه ها در عصر حاضر نیز از اجزا مهم و زیرساخت های اصلی زندگی نوین و توسعه کشورها به شمار می روند. جاده ها ساخته دست بشر هستند و جوامع گیاهی کنار جاده تحت تأثیر ساخت و ساز قرار دارند. پوشش "رودرال" به مجموعه ای از پ...

nowadays,tourism industry considered as one of the main sources of income of a country.unfortunately and despite of owning plenty of cultural historical and natural attractions, iran has not reached to a proper position in this field. besides, the historical cities of a country are considered as the income resource and national wealth of it. qazvin with a rich cultural precedent, have suitable ...