نتایج جستجو برای: hydraulic gradient and soil texture

تعداد نتایج: 16890477  

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه گیلان - دانشکده فنی 1393

asymmetric membranes are widely used in many industrial membrane separation processes. the major advantage of membrane filtration over the conventional process is its ability to remove a wider spectrum of particles without using any chemicals. hollow fiber configuration offer many advantages over flat-sheet or tubular membranes. the spinning process of hollow fiber may look simple, yet it is te...

ژورنال: علوم آب و خاک 2014

There chemical and organic matter content in garbage leachate that may affect soil physical and hydraulic properties. The main objective of this study was to evaluate the influences of the leachate of Isfahan Organic Fertilizer Factory (IOFF) on some soil physical and hydraulic properties in a soil chemically enriched by Zeolite. The treatments include two soil textures (clay loam and sandy loa...

2006
K.-J. S. Kung

It is well known that there is a spectrum of pores in a soil profile. The conventional use of a single lumped value of soil hydraulic conductivity to describe a spectrum of hydraulically active pores may have unintentionally impeded the development of field-scale chemical transport theoryand perhaps indirectly hindered the development ofmanagement protocols for chemical application andwaste dis...

2004
M Tuller

A soil-water characteristic (SWC) curve describes the amount of water retained in a soil (expressed as mass or volume water content, m or v) under equilibrium at a given matric potential. An SWC is an important hydraulic property, related to size and connectedness of pore spaces, hence strongly affected by soil texture and structure, and by other constituents, including organic matter. Modeling...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه تربیت مدرس - دانشکده مهندسی عمران 1388

چکیده روش های متعددی برای برآورد رواناب حاصل از بارش در حوضه های آبریز وجود دارد. یکی از این روش ها استفاده از مدل های هیدرولوژیکی است. با استفاده از مدل های هیدرولوژیکی و شبیه سازی فرآیندهای هیدرولوژیکی می توان با صرف کمترین زمان و هزینه، رواناب و مولفه های دیگر چرخ? هیدرولوژیکی را برآورد کرد. از آنجا که در حوضه های آبریز اندازه گیری تمام کمیت های مورد نیاز برای تحلیل رواناب ممکن نیست، انتخاب...

2013
Chengchen Pan Halin Zhao Xueyong Zhao Huibang Han Yan Wang Jin Li

Grassland salinization causes considerable changes to soil and vegetation, which can lead to changes in soil organic carbon (C) and total nitrogen (N). These changes have complex causal relationships. A significant correlation between soil organic C and total N and any soil or vegetation property does not necessarily imply a significant direct effect of the property on soil organic C and total ...

2013
Paolo Nasta Nunzio Romano Shmuel Assouline Jasper A. Vrugt Jan W. Hopmans

[1] Simultaneous scaling of soil water retention and hydraulic conductivity functions provides an effective means to characterize the heterogeneity and spatial variability of soil hydraulic properties in a given study area. The statistical significance of this approach largely depends on the number of soil samples collected. Unfortunately, direct measurement of the soil hydraulic functions is t...

Journal: :مدیریت آب و آبیاری 0
محمود مشعل استادیار گروه مهندسی آبیاری و زهکشی، پردیس ابوریحان، دانشگاه تهران حامد سهرابی دانش آموخته کارشناسی ارشد گروه مهندسی آبیاری و زهکشی، پردیس ابوریحان، دانشگاه تهران مریم وراوی پور استادیار گروه مهندسی آبیاری و زهکشی، پردیس ابوریحان، دانشگاه تهران قاسم زارعی استادیار مؤسسه تحقیقات فنی و مهندسی، کرج، البرز

saturated hydraulic conductivity (ks) is one of the most important physical features of soil that have wide usage in soil and water science. measuring ks carries on laboratory and field. guelph permeameter (gp) method is one of the field measuring method for determining field saturated hydraulic conductivity (kfs) above the ground water table. well-shape-factor (c) is one important parameter ne...

2009
D. D. Bosch

Steady-state and transient one-dimensional unsaturated flow in vertically stratified porous media are examined. Saturated hydraulic conductivity and the alpha parameter of the exponential hydraulic conductivity function were assumed to vary from soil layer to soil layer. The use of effective unsaturated hydraulic conductivity to compute matric potential in the soil profile is demonstrated. Resu...

Journal: :تحقیقات آب و خاک ایران 0
پریسا مشایخی دانشجوی دکتری/دانشگاه شهرکرد شجاع قربانی دشتکی هیئت علمی محمدرضا مصدقی هیات علمی/دانشگاه صنعتی اصفهان حسین شیرانی هیات علمی/دانشگاه حضرت ولی عصر رفسنجان مهدی پناهی هیات علمی/موسسه تحقیقات خاک و آب کرج محمدرضا نوری هیات علمی/دانشگاه شهرکرد

in this study, hydrus2d/3d software was used to estimate the hydraulic parameters of van genuchten-mualem model via inverse modeling using double-ring infiltrometers data in 3 different soil textures. nine scenarios of inverse modeling (divided in three groups) were considered with different number (5, 4 and 3) of fitted hydraulic parameters for optimization. in the first group, simulation was ...

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