نتایج جستجو برای: critical hydraulic gradient

تعداد نتایج: 628141  

2006
Alan REMPEL

Glaciers are permeated by liquid veins that line the triple junctions between ice grains and act as conduits for material transport. The density difference between water and ice produces a hydraulic gradient that drives liquid flow down towards the glacier bed. We investigate how variations in this transport rate are manifest in the lower regions of a glacier that floats on a subglacial reservo...

2013
Erhan Caliskan

Forest roads are the base infrastructure foundation of forestry operations. These roads entail a complex engineering effort because they can cause substantial environmental damage to forests and include a high-cost construction. This study was carried out in four sample sites of Giresun, Trabzon(2) and Artvin Forest Directorate, which is in the Black Sea region of Turkey. The areas have both st...

2016
Usman Anwar Randall K. Kolka John Tyndall Randall Kolka

Predicting the hydrologic consequences of biomass cropping systems requires an understanding of how different crops and management practices affect soil hydraulic properties across space and time. To inform such predictions, I investigated the impacts of five biomass cropping systems on the hydraulic properties of soils across a landscape gradient in wet, dry, and average rainfall years. I used...

2008
Jennifer E. Pyzoha Timothy J. Callahan Ge Sun Carl C. Trettin Masato Miwa

This paper describes how climate influences the hydrology of an ephemeral depressional wetland. Surface water and groundwater elevation data were collected for 7 years in a Coastal Plain watershed in South Carolina USA containing depressional wetlands, known as Carolina bays. Rainfall and temperature data were compared with water-table well and piezometer data in and around one wetland. Using t...

Journal: :Plant physiology 2016
Hugo J de Boer Paul L Drake Erin Wendt Charles A Price Ernst-Detlef Schulze Neil C Turner Dean Nicolle Erik J Veneklaas

Leaf veins supply the mesophyll with water that evaporates when stomata are open to allow CO2 uptake for photosynthesis. Theoretical analyses suggest that water is optimally distributed in the mesophyll when the lateral distance between veins (dx) is equal to the distance from these veins to the epidermis (dy), expressed as dx:dy ≈ 1. Although this theory is supported by observations of many de...

Journal: :Plant physiology 1983
D J Cosgrove R E Cleland

The water transport properties of etiolated pea (Pisum sativum L.) internodes were studied using both dynamic and steady-state methods to determine (a) whether water transport through the growing tissue limits the rate of cell enlargement, and (b) whether auxin stimulates growth in part by increasing the hydraulic conductance of the growing tissue.Measurements using the pressure probe technique...

2005
Scott Purdy

Accurately measuring the in situ hydraulic conductivity (permeability) of a clay liner is a major factor in the construction of landfill containment systems. Laboratory and large-scale field test methods are often utilized on test pads constructed prior to placement of the production liner to determine the hydraulic conductivity of the clay. While these test methods provide reliable results, th...

Journal: :Annual review of chemical and biomolecular engineering 2016
Alexander C Barbati Jean Desroches Agathe Robisson Gareth H McKinley

Nearly 70 years old, hydraulic fracturing is a core technique for stimulating hydrocarbon production in a majority of oil and gas reservoirs. Complex fluids are implemented in nearly every step of the fracturing process, most significantly to generate and sustain fractures and transport and distribute proppant particles during and following fluid injection. An extremely wide range of complex fl...

2003
Massoud Tabesh Richard Burrows

Any reliability analysis based on just deterministic values of daily average or peak demands, cannot represent the overall system reliability realistically. Using a stochastic model in this paper variations of the system and nodal reliability values are investigated through a period of time. Considering probabilistic nature of demands, this paper combines the extended period simulation of water...

2011
T. B. Warner

The petroleum industry’s use of horizontal drilling and hydraulic fracturing technologies has changed organic-rich mudstones, like the Devonian Marcellus Formation, from conventional hydrocarbon sources and seals to unconventional ‘shale gas’ reservoirs. Organic-richness and formation brittleness are two principal components of reservoir quality assessment, as the former is indicative of the am...

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