نتایج جستجو برای: hydraulic conductivity function

تعداد نتایج: 1282700  

Journal: :آب و خاک 0
الناز رضائی آباجلو کامران زینال زاده

introduction: soil hydraulic conductivity is considered as one of the most important hydraulic properties in water and solutionmovement in porous media. in recent years, variousmodels as pedo-transfer functions, fractal models and scaling technique are used to estimate the soil saturated hydraulic conductivity (ks). fractal models with two subset of two (solid and pore) and three phases (solid,...

Journal: :desert 2008
h. motaghian j. mohammadi a. karimi

soil hydrau-physical data are important for many hydrological modelings. they are the main variables controllingthe key processes such as water and chemicals movement and transport in the soil profiles. this study was conductedin order to analyze the spatial distribution of selected soil hydrau-physcial characteristics including infiltration rate(ir), saturated hydraulic conductivity (ks), bulk...

2008
M. Berli A. Carminati T. A. Ghezzehei

[1] Prediction of water flow and transport processes in soils susceptible to structural alteration such as compaction of tilled agricultural lands or newly constructed landfills rely on accurate description of changes in soil unsaturated hydraulic conductivity. Recent studies have documented the critical impact of aggregate contact characteristics on water flow rates and pathways in unsaturated...

Journal: :Waste management 2009
B Celik R K Rowe K Unlü

Leakage rates are evaluated for a landfill barrier system having a compacted clay liner (CCL) underlain by a vadose zone of variable thickness. A numerical unsaturated flow model SEEP/W is used to simulate the moisture flow regime and steady-state leakage rates for the cases of unsaturated zones with different soil types and thicknesses. The results of the simulations demonstrate that harmonic ...

Journal: :The New phytologist 2014
Alexandria L Pivovaroff Lawren Sack Louis S Santiago

Coordination of water movement among plant organs is important for understanding plant water use strategies. The hydraulic segmentation hypothesis (HSH) proposes that hydraulic conductance in shorter lived, 'expendable' organs such as leaves and longer lived, more 'expensive' organs such as stems may be decoupled, with resistance in leaves acting as a bottleneck or 'safety valve'. We tested the...

2010
Xiao-Wei Jiang Li Wan Tian-Chyi Jim Yeh Xu-Sheng Wang Liang Xu

Multi-scale heterogeneity of geological formations is a rule, which consists of random (local-scale) and systematic (large-scale) variability of hydraulic conductivity. The random variability and depth–decaying trend, a systematic variability, have different effects on subsurface flow, thus on groundwater discharge into tunnels. Little research has examined this problem in the past. Using Monte...

2001
Jan W. Hopmans

In order to better manage and monitor fluid flow and migration of chemicals in gas and liquid phases, a fundamental understanding and knowledge of the saturation dependency of permeability, diffusion and electrical conductivity in a porous medium is required. The initial fundamental formulations and recent research for characterization of transport properties in porous media are discussed. To i...

Journal: :The New phytologist 2011
Brendan Choat Danielle E Medek Stephanie A Stuart Jessica Pasquet-Kok John J G Egerton Hooman Salari Lawren Sack Marilyn C Ball

Hydraulic traits were studied in temperate, woody evergreens in a high-elevation heath community to test for trade-offs between the delivery of water to canopies at rates sufficient to sustain photosynthesis and protection against disruption to vascular transport caused by freeze-thaw-induced embolism. Freeze-thaw-induced loss in hydraulic conductivity was studied in relation to xylem anatomy, ...

Journal: :آب و خاک 0
رضا لاله زاری سعید برومند نسب هادی معاضد علی حقیقی

introduction: groundwater is the largest resource of water supplement and shortages of surface water supplies in drought conditions that requires an increase in groundwater discharge. groundwater flow dependson the subsurface properties such as hydraulic gradient (water table gradient or head loss in artesian condition) and hydrodynamic coefficients. the flow treatment is analyzed with an accur...

2007
Sherry Summers

This paper describes the scientific principles of Darcy’s law and hydraulic resistance as they relate to the in-ground dispersal of onsite wastewater effluent. A clear understanding of how water moves into the ground via dispersal trenches is needed to facilitate proper system design and effect some standardization of dispersal trench sizing and design. Hydraulic conductivity of the media, hydr...

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