نتایج جستجو برای: particle size distribution curve

تعداد نتایج: 1344075  

Journal: :تحقیقات مهندسی کشاورزی 0
بهزاد قنبریان علویجه دانشجوی سابق کارشناسی ارشد عبدالمجید لیاقت دانشیار دانشکده مهندسی آب و خاک دانشگاه تهران مهدی شرفا استادیار دانشکده مهندسی آب و خاک دانشگاه تهران سامان مقیمی عراقی استادیار دانشکده فیزیک دانشگاه صنعتی شریف.

the soil water retention curve (swrc) is a basic characteristic of the determination of soil hydraulic properties, including unsaturated hydraulic conductivity. measurement of this curve is essential to research, thus scientists have focused on indirect methods such as pedotransfer functions and empirical relationships to estimate swrc easily. since there is a close relationship between swrc an...

حمیدرضا فولادمند, ,

  Soil particle size distribution and bulk density are used for estimating soil-moisture characteristic curve. In this model, soil particle size distribution curve is divided into a number of segments, each with a specific particle radius and cumulative percentage of the particles greater than that radius. Using these data, soil-moisture characteristic curve is estimated. In the model a scale f...

ژورنال: علوم آب و خاک 2007
حمیدرضا فولادمند, ,

  Soil particle size distribution and bulk density are used for estimating soil-moisture characteristic curve. In this model, soil particle size distribution curve is divided into a number of segments, each with a specific particle radius and cumulative percentage of the particles greater than that radius. Using these data, soil-moisture characteristic curve is estimated. In the model a scale f...

Journal: :تحقیقات مهندسی کشاورزی 0
علی اصغر خوشنود یزدی مربی آموزشکده کشاورزی شیروان، دانشگاه فردوسی مشهد بیژن قهرمان استادیار گروه آبیاری دانشکده کشاورزی، دانشگاه فردوسی مشهد

the arya and paris model is a commonly accepted method to translate a particle-size distribution curve into a corresponding soil moisture characteristic curve using scaling parameter (α). the scaling parameter, in the original model of arya and paris (1981), was assumed constant (α=1.38) for all soil texture classes. in recent years, several studies have shown that α is not constant and its qua...

ژورنال: علوم آب و خاک 2004
حمیدرضا فولادمند, , علیرضا سپاسخواه, , جانب‌اله نیازی, ,

To obtain soil-moisture characteristic curve experimentally is time-consuming and usually subject to considerable errors. So, many investigators have tried to predict soil-moisture characteristic curve by different models. One of these models predicts soil moisture characteristic curve based on soil particle size distribution and bulk density. In this model, soil particle size distribution curv...

حمیدرضا فولادمند, , علیرضا سپاسخواه, , جانب‌اله نیازی, ,

To obtain soil-moisture characteristic curve experimentally is time-consuming and usually subject to considerable errors. So, many investigators have tried to predict soil-moisture characteristic curve by different models. One of these models predicts soil moisture characteristic curve based on soil particle size distribution and bulk density. In this model, soil particle size distribution curv...

Journal: :آب و خاک 0
محمدمهدی چاری بیژن قهرمان کامران داوری علی اصغر خشنود یزدی

introduction: water and soil retention curve is one of the most important properties of porous media to obtain in a laboratory retention curve and time associated with errors. for this reason, researchers have proposed techniques that help them to more easily acquired characteristic curve. one of these methods is the use of fractal geometry. determining the relationship between particle size di...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه علوم و فنون مازندران 0

مدل روزنه های موازی موج دار (corrugated oarallel bundle model) برای تعریف اثر ساختمان روزنه ها در نفوذ-واکنش (diffusion and reaction) در کاتالیستهای متخلخل بکار می رود. در مدل روزنه های موج دار، از یک دسته روزنه های اصلی (pore) استفاده شده است . هر یک از این روزنه های اصلی دارای یکسری عناصر روزنه می باشد که هر عنصر دارای یک شعاع تعیین شده به صورت اتفاقی از یک توزیع اندازه روزنه ها (pore size di...

Journal: :iranian journal of chemistry and chemical engineering (ijcce) 2011
fatemeh zabihi mohammad mahdi akbarnejad ali vaziri yazdi mahdi arjomand ali akbar safekordi

dissolution pressure and nozzle temperature effects on particle size and distribution were investigated for ress (rapid expansion of supercritical solution) process. supercritical co2 was used as solvent and ibuprofen was applied as the model component in all runs. the resulting ibuprofen nano-particles (about 50 nm in optimized runs) were analyzed by sem and laser diffraction particle size ana...

Journal: :آب و خاک 0
صادقی صادقی قهرمان قهرمان داوری داوری

abstract in recent years, many researchers have attempted to estimate the soil hydraulic functions (e.g. soil moisture characteristics curve, and hydraulic conductivity function) using particle-size distribution (psd) curve. in these studies, an accurate mathematical representation of psd is required for fitting the observed data. so far, some mathematical models were developed with different l...

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