نتایج جستجو برای: unsaturated soil

تعداد نتایج: 195589  

Journal: :Remote Sensing 2017
Chang-Hwan Park Andreas Behrendt Ellsworth LeDrew Volker Wulfmeyer

Microwave remote sensing techniques are used, among others, for temporally and spatially highly-resolved observations of land-surface properties, e.g., for the management of agricultural productivity and water resource, as well as to improve the performances of numerical weather prediction and climate simulations with soil moisture data. In this context, the effective dielectric constant of the...

Journal: :E3S web of conferences 2023

The importance of degree soil saturation in geotechnical problems resulted inclusion unsaturated mechanics various applications for several decades. However, spite recent progress remotely sensed moisture measurement, community has not yet taken advantage these advances analysis soils. NASA launched its Soil Moisture Active Passive (SMAP) satellite 2015 with the aim providing surface and root z...

2002
S. O. Eching

Inverse solution techniques currently used for estimating unsaturated soil hydraulic functions from laboratory outflow experiments use cumulative outflow only in combination with initial and final soil water pressure head values. Additional soil water information is needed to improve the estimation procedure and to minimize uniqueness problems. It was the objective of this study to experimental...

2009
Y. J. Cui A. M. Tang C. Loiseau P. Delage Yu-Jun Cui

Highly compacted sand-bentonite mixtures are often considered as possible engineered barriers in deep high-level radioactive waste disposals. In-situ, the saturation of these barriers from their initially unsaturated state is a complex hydro-mechanical coupled process in which temperature effects also play a role. The key parameter of this process is the unsaturated hydraulic conductivity of th...

2008
C. Yang Yu-Jun CUI

On the basis of plastic bounding surface model, the damage theory for structured soils and unsaturated soil mechanics, an elastoplastic model for unsaturated loessic soils under cyclic loading has been elaborated. Firstly, the description of bond degradation in a damage framework is given, linking the damage of soil’s structure to the accumulated strain. The Barcelona Basic Model (BBM) was cons...

2002
EDWARD D. KORN CHARLES L. GREENBLATT

On the basis of the unsaturated fatty acids which they synthesize, protists can be grouped in a meaningful way. Thus, the unsaturated fatty acids of the true slime mold are identical with the unsaturated fatty acids of the soil amoebae Acanthumoeba and Hartmannella but have no resemblance to those of the cellular slime mold Dictyostelium. Among the zooflagellates, Leishmania enriettii and Leish...

2004
Zhiming Lu Dongxiao Zhang

In this study, we derive analytical solutions of the first two moments (mean and variance) of pressure head for one-dimensional steady state unsaturated flow in a randomly heterogeneous layered soil column under random boundary conditions. We first linearize the steady state unsaturated flow equations by Kirchhoff transformation and solve the moments of the transformed variable up to second ord...

Journal: :تحقیقات آب و خاک ایران 0
میلاد نوری دانشجوی کارشناسی ارشد گروه خاک شناسی دانشگاه تربیت مدرس مهدی همایی استاد گروه خاک شناسی دانشگاه تربیت مدرس محمد بای بوردی استاد گروه خاک شناسی دانشگاه تربیت مدرس

to examine hydraulics of lnapls in soil, the retention curves of diesel fuel and water were both determined by hanging column method. the soil retention parameters were obtained based on van genuchten, brooks-corey and campbell’s models. in addition, the soil hydraulic conductivity for both fluids were predicted based on mualem- brooks-corey, burdine- brooks-corey, mualem-van genuchten and camp...

2007
Richard G. Niswonger David Rassam David E. Prudic

GSFLOW is a new U.S. Geological Survey model for simulating ground-water/surface-water interactions. GSFLOW couples PRMS (the Precipitation Runoff Modeling System) to MODFLOW (the Modular Ground-Water Model) with modules for simulating flow and storage in unsaturated-zones, lakes, and streams. GSFLOW simulates infiltration, runoff generation, and lateral flow in temporarily saturated material (...

2007
Vitaly A. Zlotnik Tiejun Wang John L. Nieber Jirka Šimunek

Efforts to find solutions that can be used for verification of numerical techniques for solving the Richards equation have generated a wealth of approximate and exact analytical solutions. Coefficients of this equation involve two highly non-linear functions related to the soil water potential, the unsaturated hydraulic conductivity, and the soil water content. The known exact solutions for rea...

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