نتایج جستجو برای: moments and wind erosion climatic factor were used to evaluate the regional climates tendency effect on wind erosion in yazd province wind erosion climatic factor is calculated from wind speed quantiles

تعداد نتایج: 25568089  

Journal: :مرتع و آبخیزداری 0
محمد اکبریان مربی دانشگاه هرمزگان، ایران سیّد حسن کابلی دانش آموخته دکتری مرتعداری، دانشکده منابع طبیعی، دانشگاه تهران، ایران. نوازاله مرادی مربی دانشگاه هرمزگان، ایران.

determining the relative sensitivity of land to erosion and its factors, could be the basis of soil conservation programs. the aim of this study is to compare water and wind erosion functions in land degradation of dasht-e-jeihoon using psiac and irifr.ea models and the source studying of aeolian sediments in geomorphologic facieses as homogeneous units. the results indicate that in dasht-e-jei...

Introduction: The occurrence of dust storms in deserts or arid regions increases the suspended dust particles to more than the allowed threshold, and this has negative effects on atmospheric conditions, human health and agricultural production. Positioning of Iran in the world arid and semi-arid belt is exposed to various types of dust storm systems. Occurrence of severe dust storms in most par...

گورابـی, ابـوالقاسـم , یمـانی, مجتبـی ,

Dry climate, poor vegetation and relatively smooth surface and neighborhood with plain Lute are the most important factors that brought about wind erosion processes prevail in the Kerman region. Obviously, wind erosion rate and volume of material transfer depends on characteristics of speed and direction also frequency of wind as well as surface and sediment characteristics. The purpose of this...

Journal: :آب و خاک 0
سکینه پورمند احمد غلامعلی زاده آهنگر عبدالحمید دهواری

introduction: wind erosion is one of the most important factors in desert environments. prevailing winds can shift sand dunes and affect their accumulation and morphology. also, wind regime determines the direction of sand dune mobility in different ways. therefore, the wind regime, frequency, direction and velocity are supposed to be the most important factors to form the morphology of sand du...

The main parts of Iran have been countered in arid and hyper arid area that in result of especial environmental condition as low precipitation and vegetation density can be caused wind erosion, whereas wind erosion usually has a tiny destruction quantity than water erosion due to wide its activity. Because of not matching presented models by other countries with climate and edaphic condition of...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه پیام نور - دانشگاه پیام نور استان تهران - پژوهشکده علوم انسانی و اجتماعی 1390

this study attempts to investigate the effect of peers’ revision in comparison to that of the teacher, and whether peers’ comments and teachers’ comments facilitate students’ revision? if yes, which one is more effective? also attempts have been made to see which aspects of language are more highlighted by peers versus teachers when commenting. besides, it is investigating the student’s attitud...

2013
X Yang J Leys

This paper describes spatial modeling methods to identify wind erosion hazard (WEH) areas across Australia using the recently available time-series products of satellitederived ground cover, soil moisture and wind speed. We implemented the approach and data sets in a geographic information system to produce WEH maps for Australia at 500 m ground resolution on a monthly basis for the recent thir...

this thesis attempts to investigate the effects of prelistening activities on enhancing iranian efl learners` listening comprehension. the present study investigated ways in which learners` background knowledge could be activated in order to enhance their l2 listening comprehension by limiting the number of possible text interpretations prior to listening. the experiments conducted in this study examined the effect of prior knowledge and vocabulary teaching on iranian efl learners listening comprehension. the current study has two purposes: one is to investigate the effect of background knowledge on the second language listening comprehension of iranian intermediates and the other is to determine whether second language is facilitated by the introduction of unknown vocabularies in the form of prelistening activities. to conduct the study different instruments such as listening proficiency test and four listening tests such as pre and posttests were used and various statistical processes and techniques including paired-sample t-test, and analysis of variance (anova) were used. the findings of this study supported all three hypotheses tested. differences were found between the means of preteaching vocabulary variable, the background knowledge activation variable, and mean difference between these two strategies variable. subjects scored higher when the unknown words were taught in advance. likewise, subjects scored higher when they were asked some relevant questions about the topic than on those without them. there was, in addition, a significant difference between the means of preteaching vocabulary strategy and background knowledge activation strategy. in fact, preteaching vocabulary had a better effect in enhancing the students’ listening comprehension, in comparison to background knowledge activation strategy.

پایان نامه :دانشگاه آزاد اسلامی - دانشگاه آزاد اسلامی واحد تهران مرکزی - دانشکده زبانهای خارجی 1390

this thesis attempts to investigate the effects of prelistening activities on enhancing iranian efl learners` listening comprehension. the present study investigated ways in which learners` background knowledge could be activated in order to enhance their l2 listening comprehension by limiting the number of possible text interpretations prior to listening. the experiments conducted in this stud...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه الزهراء - دانشکده علوم تربیتی و روانشناسی 1391

abstract: research purpose: the purpose of this research is to identify academic databases assessment factors and criteria at law and political science majors. the necessity of this research is to distinguish academic databases assessment factors and criteria and to identify the most important ones and rank them in order to select an appropriate database according to students’ and faculty memb...

Journal: Desert 2008
N. Mashhadi S. Feiznia

The result of wind dynamic (capacity and potential) is transport of soil or sediment particles and subsequent formative desert landforms based on the severity of erosion or sedimentation. The Khartouran region, because of its geology, geomorphology and climatology conditions is a special place in the arid region on the closed basin of Dasht-e-kavir. It is evident that the ecosystem balance of t...

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