نتایج جستجو برای: sediment particle

تعداد نتایج: 210022  

Journal: :تحقیقات آب و خاک ایران 0
سیده کوثر دانش یار دانشجوی کارشناسی ارشد گروه خاک شناسی دانشکدة علوم کشاورزی دانشگاه گیلان حسین اسدی استادیار گروه خاک شناسی دانشکدة علوم کشاورزی دانشگاه گیلان سید علی موسوی مربی گروه مهندسی آب دانشکدة علوم کشاورزی دانشگاه گیلان

the understanding soil erosion processes and the development of accurate erosion prediction models require understanding of detachment, deposition and sediment transport in rills. to evaluate the effect of soil type and flow stream power on the relative importance of flow driven processes of sediment transport, and on the boundary between the processes regarding to particle size, experiments we...

2014
Kazuya Yoshimura Yuichi Onda Takehiko Fukushima

This study used particle size analysis to investigate the initial accumulation and trap efficiency of radiocesium ((137)Cs) in four irrigation ponds, ~4-5 months after the Fukushima Dai-ichi nuclear power plant (DNPP) accident. Trap efficiency, represented by the inventory of (137)Cs in pond sediment to the inventory of radiocesium in soil surrounding the pond (i.e., total (137)Cs inventory), w...

2001
Tim Lauck Roland Lamberson Thomas E. Lisle

Salmonid embryos depend on the adequate flow of oxygenated water to survive and interstitial passageways to emerge from the gravel bed. Spawning gravels are initially cleaned by the spawning female, but sediment transported during subsequent high-runoff events can nfiltrate the porous substrate. In many gravel-bed channels used for spawning, most of the infiltrating sediment consists of sand an...

2003
Andreas Krein Ellen Petticrew Thomas Udelhoven

As many particle-associated contaminants and nutrients are supply controlled, the question of particle source is crucial. In addition, sediment storage has important implications for the delivery and fate of pollutants. Increased accumulations of fine sediment ( < 63 Am) in gravel beds not only modify benthic habitat but also increase the retention time of sediment-associated contaminants in th...

احمد جلالیان, , حمیدرضا کریم‌ زاده, ,

For the study of field wind erosion and the design and evaluation of wind erosion control techniques, detailed observations of soil particle transport and vertical destribution of eroded soil particles are needed. The objectives of this study were: 1) To describe one device for soil transport particle measurement, i. e. the BSNE sediment catcher and 2) To assess vertical distribution of wind–er...

ژورنال: علوم آب و خاک 2002
احمد جلالیان, , حمیدرضا کریم‌ زاده, ,

For the study of field wind erosion and the design and evaluation of wind erosion control techniques, detailed observations of soil particle transport and vertical destribution of eroded soil particles are needed. The objectives of this study were: 1) To describe one device for soil transport particle measurement, i. e. the BSNE sediment catcher and 2) To assess vertical distribution of wind–er...

Journal: :آب و خاک 0
بهرامی یاراحمدی بهرامی یاراحمدی شفاعی بجستان شفاعی بجستان

abstract in all river engineering projects, determination of flow resistance is essential. most commonly, the manning roughness coefficient, , is used to describe the flow resistance or relative roughness of main channel or flood plane. over the past decades little or no study has been conducted to investigate the effects of particle shapes on manning roughness coefficient. therefore, it is the...

2012
NOOR AZHAR

43 surface sediment samples from Kemaman mangrove forest, Terengganu were analyzed for sediment characteristic (mean, sorting and skewness) off two seasons (dry season and wet season) by using the Particle Size Analyzer (PSA) after digest the sample with Hydrogen Peroxide (H2O2) and Hydrochloric Acid (HCl). There is a significant (P<0.05) relationship between sediment characteristic with the se...

Journal: :journal of agricultural science and technology 2012
s. h. sadeghi m. kiani harchegani

soil erosion causes sediments to be detached from their source materials and transported as suspended particles. the present study was conducted to evaluate the effects of sand exploitation on the distribution of suspended sediments in the educational and research forest watershed of tarbiat modares university, which comprises approximately 50,000 ha. fifty-one water samples were collected befo...

2010
D. E. WALLING J. C. WOODWARD D. E. Walling J. C. Woodward

The alluvial flood plains of lowland Britain contain thick sequences of fine-grained sediment that result from the deposition of suspended sediment during flood events. These environments constitute important storage zones for a wide range of sediment-associated nutrients and con­ taminants and many of the geochemical properties of the deposited sediment are strongly related to particle size. R...

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