نتایج جستجو برای: index of geo
تعداد نتایج: 21192301 فیلتر نتایج به سال:
abstract the present study investigated the effects of task types and involvement load hypothesis on incidental learning of 10 target words (tws) in junior high schools (jhss) in givi, ardabil. the tasks deployed in this study were two input-based tasks (reading plus dictionary use with an involvement index of 3, and reading plus gap-fill task with an involvement index of 2), and one output-ba...
oil and pollutants resulting from its extraction and exploitation are considered as one of the serious problems for human health. vast oil fields of ahvaz city located in southern iran are known as one of controversial subjects in contamination with heavy metals. in this study, oil fields' soils of ahvaz city (ab-teymour) were chemically analyzed in order to determine the concentration of eight...
طوفان های گرد و غباری که اغلب در مناطق خشک و نیمه خشک جهان روی می دهند حجم زیادی از ذرات معلق را با خود حمل میکنند و از اینرو به عنوان یکی از مهمترین معضلات زیست محیطی در مقیاس های منطقه ای و بین المللی تلقی میگردند. این تحقیق به ارزیابی مقادیر فلزات سنگین در ذرات گرد و غبار ته نشین شده در شهرهای سنندج، خرم آباد و اندیمشک در غرب ایران میپردازد. نمونه برداری ذرات گرد و غبار از 30 خرداد 1391 بمدت...
any change in the refractive index of a laser active medium can lead to serious degradation of beam quality, laser beam modes, laser performance and variation in the intensity distribution. alteration in the refractive index of laser active medium is especially notable in high power lasers. it is clear that in the laser beam production, the pumping agent induces a great amount of heat which...
in this thesis, first the notion of weak mutual associativity (w.m.a.) and the necessary and sufficient condition for a $(l,gamma)$-associated hypersemigroup $(h, ast)$ derived from some family of $lesssim$-preordered semigroups to be a hypergroup, are given. second, by proving the fact that the concrete categories, semihypergroups and hypergroups have not free objects we will introduce t...
در سالیان اخیر پدیده حزن انگیز گرد و غبار گاها آسمان غرب ایران را اشغال کرده و زندگی مردم را تحت تاثیرات زیانبار خود قرار داده است. پدیده گرد و غبار که به عنوان مهمترین معضل زیست محیطی کشور در دهه اخیر قلمداد می شود واجد طیف وسیعی از خسارات و اثرات منفی است که باعث گردیده این موضوع از یک شکل محلی به بحرانی بین المللی تبدیل شود. این پایان نامه به مقایسه خصوصیات فیزیکوشیمیایی ذرات گرد و غبار در...
abstract because of the many geopolitical, geo economical and geo strategically potentials and communicational capabilities of eco region, members can expand the convergence and the integration in base of this organization that have important impact on members development and expanding peace in international and regional level. based on quality analyzing of library findings and experts interv...
background: sediments are inseparable fractions of wetland ecosystems that work as a his-torical archive in the process of recording heavy metal aggregation changes. this study was carried out for assessing co, ni, and zn in sediment samples of mighan wetland using geo-accumulation index in 2013. methods:the sediment samples were taken from 11 stations. the samples were subjected to bulk digest...
the concentration of selected trace metals (fe, cd, cu, pb, and zn) in 30surface sediments were measured using atomic absorption spectrometer to investigatethe spatial and seasonal variations of trace metals along kanyakumari coast, india. toassess the environmental risk of trace metals, enrichment factor, geo-accumulation index,pollution load index, and ecological risk index have been calculat...
pollution of water and soils by heavy metals is an emerging problem in industrialized countries.the present study was conducted to investigate the heavy metals concentration in water and sedimentsamples from ship breaking sites of sitakunda to assess the potential ecological risk posed by heavy metalusing different methods. heavy metals concentration was analyzed by atomic absorption spectrosco...
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