نتایج جستجو برای: hydraulic parameters

تعداد نتایج: 603489  

ژورنال: علوم آب و خاک 2019

Simulation of water and salt transfer in soil is very effective in managing optimal water and fertilizer use in the field. In this study, the HYDRUS-1D model was used to simulate the transfer of water and bromide in a laboratory column of soil with clay loam texture. Soil hydraulic parameters (including air entry point) α, (saturated hydraulic conductivity) ks, (residual moisture content) θr (s...

Journal: :تحقیقات آب و خاک ایران 0
حجت احمدی استادیار گروه آب دانشگاه ارومیه حسین رضایی دانشیار گروه آب دانشگاه ارومیه کامران زینالزاده استادیار گروه آب دانشگاه ارومیه

seepage analysis through earth dams is employed to determine the water loss. moreover, as the magnitude of pore pressure in dam body is calculated using seepage analysis, this analysis plays an important role on the stability analysis in these types of structures. as the hydraulic conductivity of the earth dam materials, is considered as one of the effective parameters on the magnitude of seepa...

2012
M Osman Abdalla Fakhruldin M Hashim

Hydraulic cylinder actuators are used extensively in industrial, construction and agricultural works. The small sized outlet ports of the cylinders resist the flow of discharged oil; and as a result the piston motion is slowed down. This causes a lot of heat generation and energy loss within the actuators. The study investigates and analyzes the possibilities of reducing the hydraulic resistanc...

ژورنال: علوم آب و خاک 2012
بیژن خلیل‌مقدم, , جهانگرد محمدی, , حبیب خداوردی‌لو, , سیروس دهقانی بانیانی, , شجاع قربانی دشتکی, ,

Saturated hydraulic conductivity (Kfs) and macroscopic capillary length of soil pores are important hydraulic properties for water flow and solute transport modeling. Measuring these parameters is tedious, time consuming and expensive. One way is using indirect methods such as Pedotransfer functions (PTFs). The objective of this research was to develop some PTFs for estimating saturated hydraul...

ژورنال: علوم آب و خاک 2018

In this study, the values of moisture and soil temperature were estimated at different depths and times under unsteady conditions by solving the Richards’ equation in an explicit finite difference method provided in Visual Studio C#. For the estimation of soil hydraulic parameters, including av and nv (coefficients of van Genuchten’s equation) and Ks (saturated hydraulic conductivit...

2007
L. Ma P. Heilman L. R. Ahuja T. Meade R. S. Kanwar

Process-based agricultural system models require detailed description of soil hydraulic properties that are usually not available. The objectives of this study were to evaluate the sensitivity of model simulation results to variability in measured soil hydraulic properties and to compare simulation results using measured and default soil parameters. To do so, we measured soil water retention cu...

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...

2014
Kai LI Lingfeng TANG Youmin WANG Chun ZHAO

In order to study the numerical control (NC) servo press hydraulic control system and its control algorithm. The numerical control servo press performance and control principle of hydraulic control system are analyzed. According to the flow equation of the hydraulic control valve, hydraulic cylinder flow continuity equation and the force balance equation of the hydraulic cylinder with load pres...

Journal: :Ground water 2006
Walter A Illman Daniel M Tartakovsky

Illman and Tartakovsky (2005a, 2005b) developed a new approach for the interpretation of three-dimensional pneumatic well tests conducted in porous or fractured geologic media, which is based on a straight-line analysis of late-time data. We modify this approach to interpret three-dimensional well tests in the saturated zone and use it to analyze the cross-hole hydraulic test data collected in ...

2005
Mauro A. B. Cunha Raul Guenther

Abstract. This work presents a cascade controller for the trajectory tracking control of a hydraulic actuator by using adaptive algorithms to deal with parametric uncertainties together with an adaptive dead-zone compensation scheme. The hydraulic actuator is modeled as a forth order nonlinear system including the valve dynamic as a first order linear system and considering a valve with a dead-...

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