نتایج جستجو برای: suspended sediment yield was estimated to select best model

تعداد نتایج: 11352688  

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه فردوسی مشهد - دانشکده ادبیات و علوم انسانی دکتر علی شریعتی 1389

the current study examined iranian undergraduate efl students’ willingness to communicate with regard to their vocabulary knowledge. in general, participants were somewhat willing to communicate in english. the total mean score of 730 university students’ perception of willing to communicate was 83.53 out of 135. results, regarding four parts of willingness to communicate, revealed that part...

Fatemeh Shokrian, K. Shahedi,

Estimate of sediment load is required in a wide spectrum of water resources engineering problems. The nonlinear nature of suspended sediment load series necessitates the utilization of nonlinear methods to simulate the suspended sediment load. In this study Artificial Neural Networks (ANNs) are employed to estimate daily suspended sediment load. Two different ANN algorithms, Multi Layer Perce...

پایان نامه :دانشگاه تربیت معلم - تهران - دانشکده علوم 1393

in this thesis, structural, electronical, and optical properties of inverse pervskite(ca3pbo) in cubic phase have been investigated.the calculation have been done based on density functional theory and according to generalized gradiant approximate (gga) as correlating potential. in order to calculate the configurations, implementing in the wien2k code have been used from 2013 version. first of ...

Journal: :آب و خاک 0
صادقی صادقی سعیدی سعیدی

abstract suspended sediment resulted from distributed soil erosions facilitates soil nutrients transportation and influences soil depletion. soil erosion plays a key role in loss of organic matter and therefore study of the relationship between organic matter and soil erosion processes and soil nutrient loss is very important. the present case study was conducted in kojour educational forest wa...

Journal: :journal of agricultural science and technology 2010
f. sarmadian p. rahimy a. keshavarzi

in the present study, the soil and water assessment tool (swat 2000) model was tested on both a monthly and yearly basis and applied to the kordan watershed, located in iran. the main objective of the research was to assess the accuracy of the model in sediment-yield and surface water bicarbonate concentration estimation. the attributes of sub-watersheds, tributary channels and the main channel...

A Tashakori N Vaseli R Salehi Teleshi,

In a watershed, sediment arises due to the erosion and some factors such as pastures destruction,change users, no reasonable cultivation. That causes problems such as sedimentation in reservoirs andreduces their useful volume, reducing water quality in agricultural consumption; reduce the efficiencyof hydraulic structures and some other environmental problems. Changes in sediment load in a rive...

2004
Hyoseob KIM

Variations of suspended sediment concentration over ripples in regular waves were described using an existing numerical model system. Nielsen’s (1992) empirical formula for sediment entrainment rate from the bed surface was used with an additional scale factor in the model system. The model system was applied to two typical laboratory experimental conditions selected for description of the vari...

1999
Desmond E. Walling Philip N. Owens Graham J. L. Leeks

Statistically veri®ed composite ®ngerprints and a multivariate mixing model have been employed to establish the main sources of the suspended sediment transported through the lower, non-tidal reaches of the River Ouse and one of its main tributaries, the River Wharfe, during the period 1994±1997. In the case of the suspended sediment samples collected from the River Ouse, the load-weighted mean...

2014
Xiaopeng Jia Haibing Wang

The interaction of wind and water in semiarid and arid areas usually leads to low-frequency flash flood events in desert rivers, which have adverse effects on river systems and ecology. In arid zones, many aeolian dune-fields terminate in stream channels and deliver aeolian sand to the channels. Although aeolian processes are common to many desert rivers, whether the aeolian processes contribut...

A. Zarei M.J. Amiri

ABSTRACT- One of the big problems today human societies are faced with is the problem of soil erosion. In this study, the "MPSIAC model" was used to estimate sediment yield and provide sediment yield map in Cachoyeh watershed. The MPSIAC method incorporates nine environmental factors that contribute to sediment yield of the watershed. These factors are: surface geology, soil, climate, runoff, t...

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