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

تعداد نتایج: 21293104  

پایان نامه :دانشگاه آزاد اسلامی - دانشگاه آزاد اسلامی واحد تهران مرکزی - دانشکده زبانهای خارجی 1392

the extent to which written corrective feedback on linguistic errors can play a role in helping l2 writers improve the accuracy of their writing continues to be an issue of interest to researchers and teachers since truscott (1996) mounted a case for its abolition. while there is growing empirical evidence that written corrective feedback can successfully target some types of linguistic error (...

Journal: :محیط شناسی 0
قاسم عزیزی دانشیار اقلیم شناسی، دانشکدة جغرافیا، دانشگاه تهران علی اکبر شمسی پور استادیار اقلیم شناسی، دانشکدة جغرافیا، دانشگاه تهران مرتضی میری دانشجوی کارشناسی ارشد اقلیم شناسی، دانشکدة جغرافیا، دانشگاه تهران طاهر صفرراد دانشجوی دکترای اقلیم شناسی، دانشکدة جغرافیا، دانشگاه تهران

dust storm is a meteorological phenomenon common in arid and semi-arid regions. iran and particularly its west and south-west parts, periodically faces with the dust phenomenon and its problems. in this investigation two dust samples has been selected and studied that they has sustained over three days with visibility less than 1000m in west of iran. the first one occurred during 18 - 21 april ...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه تحصیلات تکمیلی صنعتی کرمان - پژوهشکده برق و کامپیوتر 1390

a phase-locked loop (pll) based frequency synthesizer is an important circuit that is used in many applications, especially in communication systems such as ethernet receivers, disk drive read/write channels, digital mobile receivers, high-speed memory interfaces, system clock recovery and wireless communication system. other than requiring good signal purity such as low phase noise and low spu...

پایان نامه :0 1392

it is definitely necessary to understand the concept and behavior of causation of life insurance policies and its determinants for insurance managers, regulators, and customers. for insurance managers, the profitability and liquidity of insurers can be increasingly influenced by the number of causation through costs, adverse selection, and cash surrender values. therefore, causation is a materi...

پایان نامه :دانشگاه تربیت معلم - سبزوار - دانشکده ادبیات و زبانهای خارجی 1390

this study investigated the effects of planning on second-language written production with regard to task type. the participants were 75 iranian learners of english as a foreign language attending a private foreign language institution. they were asked to complete two different types of writing tasks (expository writing task and argumentative writing task) in different planned conditions (indiv...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه سیستان و بلوچستان - دانشکده ادبیات و علوم انسانی 1392

abstract the first purpose of this study was to investigate the effect of consciousness-raising (c-r) activities on learning grammatical structures (simple present tense in this case) by iranian guidance school efl learners. the second one was to investigate the effect of gender on learning the simple present tense through c-r activities and tasks. finally, this study aimed to investigate the ...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه شاهد - دانشکده فنی و مهندسی 1387

abstract biometric access control is an automatic system that intelligently provides the access of special actions to predefined individuals. it may use one or more unique features of humans, like fingerprint, iris, gesture, 2d and 3d face images. 2d face image is one of the important features with useful and reliable information for recognition of individuals and systems based on this ...

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Dust storms are one of damaging climatic phenomena on the synoptic maps that are affected from the elements of pressure, cloudiness, precipitation, relative humidity, wind, temperature, and evaporation. According to Kermanshah province is one of the areas that is affected by the storms, the aim of this study is synoptic analysis of extreme dust storms in Kermanshah Station in 54-year period (19...

حسین حمزه, نسیم, ذوالجودی, مجتبی, رنجبر, عباس, غفاریان, پروین, فتاحی, ابراهیم,

Dust particles consist of important aerosols and resulting in blowing strong winds on the surface of desert areas. These particles enter the atmosphere under the influence of different factors including: weather condition (wind, precipitation and temperature), land surface (topography, humidity level, roughness and vegetation), soil features (texture, density, composition and land use (agricult...

Journal: :جغرافیا و مخاطرات محیطی 0
فهیمه محمدی سمیه کمالی مریم اسکندری

1. introduction dust phenomenon which occurs in arid and semiarid lands of the world is closely related to climatic characteristics of the region. according to the world meteorological organization (wmo), whenever wind speed exceeds 15 meter per second and horizontal visibility reduces to less than 1 km in a station, dust storm is reported (goudie & mideleton, 2006). great storms are created wh...

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