نتایج جستجو برای: during dust event and reducing the horizontal visibility

تعداد نتایج: 21293104  

Extended abstract 1- Introduction Dust storms are a kind of severe natural disaster indust source regions, which have a negative impact on human health, industrial products and activities. Iran is a dry  and low water country, the coincidence of this situation and its position in the global rebound belt has brought about very bad conditions. Repeaters in recent years have been affected by the...

Journal: :محیط شناسی 0
عباسعلی ولی استادیار بیابان زدایی، گروه علوم مهندسی بیابان، دانشکدۀ منابع طبیعی و علوم زمین، دانشگاه کاشان، کاشان، ایران سجاد خاموشی کارشناسی ارشد بیابان زدایی، گروه علوم مهندسی بیابان، دانشکدۀ منابع طبیعی و علوم زمین، دانشگاه کاشان، سید حجت موسوی استادیار ژئومورفولوژی، گروه جغرافیا و اکوتوریسم، دانشکدۀ منابع طبیعی و علوم زمین، دانشگاه کاشان، کاشان، ایران فاطمه پناهی استادیار بیابان زدایی، گروه علوم مهندسی بیابان، دانشکدۀ منابع طبیعی و علوم زمین، دانشگاه کاشان، کاشان، ایران احسان تمسکی کارشناسی ارشد بیابان زدایی، دانشگاه هرمزگان، بندرعباس، ایران

introduction dust storms, one type of dust event, are in most cases the result of turbulent winds, including convective haboobs, which raise large quantities of dust from desert surfaces and reduce visibility to less than 1 km. this dust reaches concentrations in excess of 6000 mg m3 in severe events. the major dust source regions are areas of arid and hyper-arid, with mean annual rainfalls of ...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه پیام نور - دانشگاه پیام نور استان تهران - دانشکده زیست شناسی 1388

126 abstract: in this research we studied the effects of cyclic hydration and dehydration of cysts of artemia urmiana and artemia parthenogenetica on the hatching percentage, survival and growth. the experiment was carried out in 3 treatments (1-3 hydration/dehydration cycles) with 3 replicates for each treatment. later effects of cold preservation at -20°c during three time periods were ...

Detecting the spatial distribution of dust storms in the deposition regions is an essential step for managing this natural and human-induced crisis. This study aimed to investigate the performance of the Normalized Differences Dust Index (NDDI) applied to MODIS data (4/7/2009) for detection of dust storms in the Khuzestan Province. The extracted NDDI map was classified by value pixel in six cla...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه فردوسی مشهد - دانشکده ادبیات و علوم انسانی دکتر علی شریعتی 1392

like any other learning activity, translation is a problem solving activity which involves executing parallel cognitive processes. the ability to think about these higher processes, plan, organize, monitor and evaluate the most influential executive cognitive processes is what flavell (1975) called “metacognition” which encompasses raising awareness of mental processes as well as using effectiv...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه صنعتی اصفهان - دانشکده شیمی 1389

in this thesis, a new optically active poly(amide-imide) (pai) was synthesized by the indirect polycondensation reaction of the l-phenylalanine based diacid chloride and 4,4?-diaminodiphenylether in the presence of triethylamine in n-methyl-2-pyrrolidone. the formation of pai was confirmed by ftir, 1h nmr and elemental analysis. in next step, the surface of titanium dioxide (tio2) nanoparticles...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه علامه طباطبایی - دانشکده اقتصاد 1389

abstract: about 60% of total premium of insurance industry is pertained?to life policies in the world; while the life insurance total premium in iran is less than 6% of total premium in insurance industry in 2008 (sigma, no 3/2009). among the reasons that discourage the life insurance industry is the problem of adverse selection. adverse selection theory describes a situation where the inf...

پایان نامه :دانشگاه تربیت معلم - تهران - دانشکده ادبیات و علوم انسانی 1391

the present study aimed at exploring cognitions of iranian english teachers within the context of english for academic purposes (eap). to this end, the cognitions of two groups of eap teachers with respect to their pedagogical content knowledge (pck) and their sense of professional identity (pi) were probed. two language teachers and two content instructors who had at least five years of eap te...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه شیراز - دانشکده علوم انسانی 1391

from 1950s onward, new theories and critical approaches burgeoned across humanities. these theories were context-oriented; as a result, the analysis of discursive practices gained significance. thus, social, political, historical and cultural discourses that have been hitherto marginalized and considered inferior to literary texts, were introduced as important texts to be analyzed by critics. o...

پایان نامه :دانشگاه تربیت معلم - تهران - دانشکده ادبیات و علوم انسانی 1389

abstract the primary purpose of this study was to explore the actual practices and cognitions of two groups of iranian eap teachers, i.e. language teachers and content teachers, with respect to teaching reading-comprehension and vocabulary. to this end, tehran university of medical sciences which authorizes both groups of teachers to teach eap courses was selected as the context of the study s...

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