نتایج جستجو برای: hydraulic

تعداد نتایج: 28732  

2008
T. W. Wietsma M. Oostrom

Knowledge of hydraulic properties, such as hydraulic conductivity and soil moisture retention, is crucial for understanding flow and contaminant transport in the subsurface. Hydraulic properties are often important input parameters for numerical simulation of flow and transport. Unfortunately, acquisition of these properties is usually time consuming and costly because of the manual labor assoc...

Journal: :The New phytologist 2008
Nate McDowell William T Pockman Craig D Allen David D Breshears Neil Cobb Thomas Kolb Jennifer Plaut John Sperry Adam West David G Williams Enrico A Yepez

Severe droughts have been associated with regional-scale forest mortality worldwide. Climate change is expected to exacerbate regional mortality events; however, prediction remains difficult because the physiological mechanisms underlying drought survival and mortality are poorly understood. We developed a hydraulically based theory considering carbon balance and insect resistance that allowed ...

Journal: :Journal of contaminant hydrology 2005
Xianda Zhao Roger B Wallace David W Hyndman Michael J Dybas Thomas C Voice

Hydraulic conductivity and sorption coefficients for chlorinated hydrocarbons (chloroform, carbon tetrachloride and tetrachloroethylene) were evaluated for 216 sediment samples collected across a 15 m transect and a 21 m depth interval in a contaminated aquifer near Schoolcraft, Michigan. Relationships between hydraulic conductivity, linear sorption partition coefficients, grain size classes, a...

2015
Andrea Ganthaler Stefan Mayr

Vaccinium myrtillus and Vaccinium vitis-idaea are two dwarf shrubs widespread in the European Alps. We studied the hydraulics of these species hypothesizing that (1) the hydraulic architecture of dwarf shrubs differs from trees, (2) hydraulic properties reflect the species' ecological amplitude and (3) hydraulic properties vary spatially and seasonally. Key hydraulic parameters (osmotic potenti...

Journal: :Plant, cell & environment 2012
Jennifer A Plaut Enrico A Yepez Judson Hill Robert Pangle John S Sperry William T Pockman Nate G McDowell

Drought-related tree mortality occurs globally and may increase in the future, but we lack sufficient mechanistic understanding to accurately predict it. Here we present the first field assessment of the physiological mechanisms leading to mortality in an ecosystem-scale rainfall manipulation of a piñon-juniper (Pinus edulis-Juniperus monosperma) woodland. We measured transpiration (E) and mode...

2014
Igor Linkov Benjamin Trump David Jin Marcin Mazurczak Miranda Schreurs

BACKGROUND The development of horizontal drilling and hydraulic fracturing methods has dramatically increased the potential for the extraction of previously unrecoverable natural gas. Nonetheless, the potential risks and hazards associated with such technologies are not without controversy and are compounded by frequently changing information and an uncertain landscape of international politics...

2015
Jun Ye

This paper proposes a dimension root distance and its similarity measure of single-valued neutrosophic sets (SVNSs), and then develops the fault diagnosis method of hydraulic turbine by using the dimension root similarity measure of SVNSs. By the similarity measure between the fault diagnosis patterns and a testing sample with single-valued neutrosophic information and the relation indices, we ...

2014
Rajiv K. Giri Krishna R. Reddy

In bioreactor landfill, the leachate flow and moisture distribution depend upon saturated and unsaturated hydraulic properties of municipal solid waste (MSW). The effects of unsaturated parameters have not been studied because of scarcity of the data and variation in unsaturated parameters due to MSW heterogeneity, degree of decomposition, and pore structure. In this study, a numerical two-phas...

2003
Sang-Gyum Kim Woon-Sung Lee Jung Ha Kim

We are studying a hydraulic system design and vehicle dynamic modeling for a development of tire roller system, because those are very important in analysis of tire roller. Generally, tire roller is one of the useful machines in a road construction field and it technically applied for many other construction fields. Also, we conceptualize of new hydraulic and traction system, and define about t...

2013
Paolo Nasta Nunzio Romano Shmuel Assouline Jasper A. Vrugt Jan W. Hopmans

[1] Simultaneous scaling of soil water retention and hydraulic conductivity functions provides an effective means to characterize the heterogeneity and spatial variability of soil hydraulic properties in a given study area. The statistical significance of this approach largely depends on the number of soil samples collected. Unfortunately, direct measurement of the soil hydraulic functions is t...

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