نتایج جستجو برای: hydraulic uncertainties

تعداد نتایج: 72257  

2013
Yongchul Shin Binayak P. Mohanty

[1] Soil moisture (SM) at the local scale is required to account for small-scale spatial heterogeneity of land surface because many hydrological processes manifest at scales ranging from cm to km. Although remote sensing (RS) platforms provide large-scale soil moisture dynamics, scale discrepancy between observation scale (e.g., approximately several kilometers) and modeling scale (e.g., few hu...

2007
J. Eggleston

Hydraulic conductivity is commonly estimated from grain size characteristics of unconsolidated sediments. We present an extensive set of air-permeability and grain size measurements from a heterogeneous aquifer. These data are unique in that the hydraulic conductivity measurements are made on undisturbed in-situ sediment and, like the grain size measurements, have a small sample volume size (<1...

Journal: :Plant physiology 1977
B E Michel

A model that relates hydraulic permeability to water flux and to gradients in pressure potential and solute potential was tested using soybean (Glycine max) plants. Water flux was varied by additions of polyethylene glycol 6,000 around one portion of a divided root system and by changing the light intensity and CO(2) concentration around the plants. The data are compatible with the model only i...

2013
Dr. Etsujiro IMANISHI Takao NANJO Akira TSUTSUI

Simulation techniques to reduce the fuel consumption in hydraulic excavators are presented in three categories: first, a strongly non-linear dynamic simulation technique for a coupling system with a non-linear hydraulic system and a linkage system; second, a technique for evaluating fuel consumption in the engine when the engine powers the hydraulic pump in a digging operation performed by a hy...

2011
Hubert CHANSON

-A free-surface flow can change from a supercritical to subcritical flow with a strong dissipative phenomenon called a hydraulic jump. Herein the progress and development in turbulent hydraulic jumps are reviewed with a focus on hydraulic jumps operating at large Reynolds numbers typically encountered in natural streams and hydraulic structures. The key features of the turbulent hydraulic jumps...

2012
Jong Shik Kim Sung Hwan Park

Conventional hydraulic actuator (CHA) systems have been widely used as power units because they can generate very large power compared to their size. In general, a CHA system consists of an electric motor, a pump, a reservoir, various valves, hoses, which are used to transfer the working fluid and an actuator. CHA systems, however, have some problems such as environmental pollution caused by th...

2016
Jan W Hopmans Charles Young G. Schoups J. W. Hopmans C. A. Young J. A. Vrugt W. W. Wallender

This paper presents the multi-criteria calibration of a regional distributed subsurface water flow model for a 1400 km irrigated agricultural area in the western San Joaquin Valley of California. Two global optimization algorithms were used to identify model parameters using data on spatially distributed local water table depth measurements, district-average groundwater pumping and district-ave...

2008
Yin Chin Choo Kashem M. Muttaqi M. Negnevitsky

Power system performance is affected by dynamic characteristics of hydraulic governor-turbines during and following any disturbance, such as occurrence of a fault, loss of a transmission line or a rapid change of load. Accurate modelling of hydraulic governor-turbines is essential to characterise and diagnose the system response during an emergency. In this article, both detailed and simplified...

Journal: :Tree physiology 2004
Peter J Franks

A better understanding of the mechanistic basis of stomatal control is necessary to understand why modes of stomatal response differ among individual trees, and to improve the theoretical foundation for predictive models and manipulative experiments. Current understanding of the mechanistic basis of stomatal control is reviewed here and discussed in relation to the plant hydraulic system. Analy...

2012
Yihong Zhao Bo Jiang Zhengkun Wu Ran Dong

The hydraulic system of mobile garbage compression equipment was studied according to its actual working conditions. A simulation model of the hydraulic system was established with AMESim software, and the speed and acceleration of the piston rod were simulated. Simulation results show that the designed hydraulic system can achieve the action requirements. The experiment also shows the similar ...

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