نتایج جستجو برای: dispersivity

تعداد نتایج: 244  

Journal: :Journal of Hydrology 2022

Choosing a suitable process-oriented eco-hydrological model is essential for obtaining reliable simulations of hydrological processes. Determining soil hydraulic and solute transport parameters another fundamental prerequisite. Research discussing the impact considering evaporation fractionation on parameter estimation practical applications isotope models limited. In this study, we analyzed re...

2002
Sabit Ersahin Robert I. Papendick Jeffrey L. Smith C. Kent Keller Valipuram S. Manoranjan

Macropore transport of chemicals in soil often causes unexpected contamination of groundwater. The effect of soil structure on the functions of various sized macropores was assessed, investigating transport of nonreactive bromide (Br) under matric heads of 0, 2, 5 and 10 cm using undisturbed soil columns from A, Bw and E horizons of a Thatuna silt loam soil (fine-silty, mixed, mesic Xeric Argia...

Journal: :Bulletin of Mathematical Biology 2008
Maarten de Gee Marjolein E. Lof Lia Hemerik

In a companion paper (Lof et al., in Bull. Math. Biol., 2008), we describe a spatio-temporal model for insect behavior. This model includes chemical information for finding resources and conspecifics. As a model species, we used Drosophila melanogaster, because its behavior is documented comparatively well. We divide a population of Drosophila into three states: moving, searching, and settled. ...

Journal: :محیط زیست طبیعی 0
فرزانه قائمی زاده دانشجوی دکتری گروه مهندسی آب، دانشکدۀ کشاورزی، دانشگاه بوعلی‏ سینا، همدان امید بهمنی استادیار گروه مهندسی آب، دانشکدۀ کشاورزی، دانشگاه بوعلی‏ سینا، همدان

determination of the best method to estimate the dispersion rate is very important to ensure accuracy of the computed data. the aim of this research is studying of transport length effects of dispersion of conservative tracer nacl in soils with different texture using several solute transport models including brigham, fried-combernous and solutions of the advection-dispersion equation with inve...

Journal: :تحقیقات آب و خاک ایران 0
محمدعلی محمودی دانشجوی دکتری، پردیس کشاورزی و منابع طبیعی مهدی شرفا استادیار، پردیس کشاورزی و منابع طبیعی مهدی همایی استاد، دانشگاه تربیت مدرس عبدالمجید لیاقت دانشیار، پردیس کشاورزی و منابع طبیعی فریبرز عباسی عضو هیات علمی موسسه تحقیقات فنی و مهندسی کشاورزی کرج

dispersivity (?) and effective transport porosity (?eff) are input parameters in equilibrium convection dispersion equation (cde). normally these parameters are obtained from breakthrough curves by inverse method. however, obtaining breakthrough curves in the field is not often possible in practice. the objective of this study was to estimate ? and feff from soil hydraulic data. for this purpos...

2007
C. K. Lee

The results form the application of the method of homogenization for the transport of solute in a porous medium with microscale pores and the rock matrix are applied to examine the dispersion characteristics of a solute in a porous rock matrix with parallel fractures including the retardation in the rock matrix and the decay effects. By using the solutions to a boundary value problem the effect...

2002
Feike J. Leij Teamrat A. Ghezzehei

for all properties whereas tillage practices contributed the most to the variation of infiltrability. Tillage causes soil fragmentation thereby increasing the proportion Quantifying the temporal dynamics of the PSD may of interaggregate (structural) pore space. The resulting tilled layer have important applications, but to do so in a determintends to be structurally unstable as manifested by a ...

Journal: :محیط شناسی 0
امید بهمنی استادیار گروه علوم و مهندسی آب، دانشگاه بوعلی سینا همدان، ایران محمد قبائی سبوق دانشجوی دکتری گروه علوم و مهندسی آب، دانشگاه بوعلی سینا همدان، ایران، معین الدین رضوانی دانشجوی دکتری گروه علوم و مهندسی آب، دانشگاه بوعلی سینا همدان، ایران عاطفه مهدوی نجف آبادی دانشجوی دکتری گروه علوم و مهندسی آب، دانشگاه بوعلی سینا همدان، ایران

introduction the movement and fate of solutes in the subsurface in affected by a large number of physical, chemical processes requiring a broad array of mathematical and physical sciences to study and describe solute transport. the dispersion is an important parameter in the advection – dispersion equation, which is used in assessing, and solving the problems related to the contamination and th...

Journal: :Hydrology and Earth System Sciences 2022

Abstract. Soil hydraulic and hydrodispersive properties are necessary for modeling water solute fluxes in agricultural environmental systems. Despite the major efforts developing methods (e.g., laboratory-based, pedotransfer functions), their characterization at applicative scales remains an imperative requirement. Accordingly, this paper proposes a noninvasive situ method integrating electroma...

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