نتایج جستجو برای: low rates of erosion

تعداد نتایج: 21265055  

Journal: :مرتع و آبخیزداری 0
گلاله غفاری دانشجوی کارشناسی ارشد آبخیزداری، دانشکدة منابع طبیعی دانشگاه تهران حسن احمدی استاد دانشکدة منابع طبیعی دانشگاه تهران امید بهمنی استادیار دانشگاه آزاد اسلامی، واحد گرمسار علی اکبر نظری سامانی استادیار دانشکدة منابع طبیعی دانشگاه تهران

in iran due to the lack of long experience in the implementation of soil conservation and watershed management plans, these measures have not been evaluated quantitatively and specific methods for this purpose have not been provided. in this research effort is to investigate the effect of watershed management operations performed in can basin in 1379, on the amount of erosion and sedimentation ...

Aims & Backgrounds: Considering the fact that a large part of our country is in arid and semi-arid regions and every year wind erosion and dust storms cause significant damages to the country's bio-economic resources, it is necessary to study this phenomenon. This study investigated the erosion rate of geomorphological facies of Gonabad city in relation to wind erosion. Methodology: The wind er...

2014
Devin McPhillips Paul R. Bierman Thomas Crocker Dylan H. Rood

[1] The landscape response to climate change is frequently investigated with models because natural experiments on geologic timescales are rare. In Quebrada Veladera, in the western Andes Mountains, the formation of alluvial terraces during periods of high precipitation presents opportunities for such an experiment. We compare drainage-average erosion rates during Pleistocene terrace deposition...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه سیستان و بلوچستان - دانشکده ادبیات و علوم انسانی 1388

abstract: the present thesis includes ; one preface and 11speeches , that each speech considered in different researches . the prefact part , studied grammer back ground , the first speech considered a brief description about grammatical credits . the second speech considered the different typs of sentences , from structure and meaning points of view . the third speech considered the verb es...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه شیراز - دانشکده ادبیات و علوم انسانی 1390

this study was carried out to investigate the effects of integrative vs. instrumental motivation, learning strategy use and gender on iranian efl learners. to this end, 120 efl learners both male and female majoring in english language and literature at shiraz university participated in the study. in order to conduct this study three instruments were used: oxford quick placement test, motivatio...

Journal: :تحقیقات جغرافیایی 0
علیرضا حبیبی پژوهشکده آبخیزداری

soil erosion is a major problem for developing countries with arid and semi-arid climate. these of erosion is possible than two ways of water and wind. in this paper, with using of two methods irifer and hierarchical models, the rate and intensity of of soil erosion is estimated shadegan catchment. for this purpose, by using various maps alike dem, rainfall, land use index, ndvi, geology estima...

2007
Eduardo Garzanti Giovanni Vezzoli Sergio Andò Jérôme Lavé Mikaël Attal Christian France-Lanord Peter DeCelles

We use petrographic and mineralogical data on modern sediments to investigate erosion patterns in the Marsyandi basin of the central Himalaya, a privileged natural laboratory in which a series of multidisciplinary geomorphological, sedimentological, geochemical and geochronological studies have been recently carried out to unravel the interrelationships between tectonic, climatic and sedimentar...

ژورنال: آبخیزداری ایران 2020

Transferring mechanic of cohesive sediments are different from non-cohesive sediments. For determining the erosion rate of non-cohesive sediments, physical parameters such as average diameter and density are used, such as average diameter and density. Due to the nature of the cohesive sediments, their erosion rates are determined interrelated with the shear stress of the bed with fixed coeffici...

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 تربیت مدرس 1382

‏‎the main purpose of this research was to:1.develop a coking model for thermal cracking of naphtha.2.study coke inhibition methods using different coke inhibitors.developing a coking model in naphtha cracking reactors requires a suitable model of the thermal cracking reactor based on a reliable kinetic model.to obtain reliable results all these models shall be solved simultaneously.for this pu...

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