نتایج جستجو برای: upward seepage
تعداد نتایج: 16462 فیلتر نتایج به سال:
We present stable isotope and geochemical data from four sediment cores from west of Prins Karls Forland (ca. 340 m water depth), offshore western Svalbard, recovered from close to sites of active methane seepage, as well as from shallower water depths where methane seepage is not presently observed. Our analyses provide insight into the record of methane seepage in an area where ongoing ocean ...
Keywords: Groundwater seepage Pedotransfer function ROSETTA Seepage erosion Uncertainty analysis s u m m a r y Research has suggested that streambank seepage can be an important mechanism of bank instability; however, limited information is available on the level of soil characterization necessary to accurately predict seepage gradient forces and erosion. The objective of this research was to q...
To optimize the use of water for agriculture, knowledge of the seepage of the channel is required. Although there are many empirical equations for estimating canal seepage, the coefficients of these equations are different from Iranian conditions and these equations vary in different areas. In this research, the ability of the SEEP model was studied to estimate the seepage from earth canals in ...
Seepage-face boundaries are common features of unconfined ground water flow. These boundaries exist at the intersection of an unconfined aquifer and a surface water body such as a lake, river, or wetland. The existence of a seepage-face boundary is necessary to provide a physical transition between the internal water-table boundary and the external equipotential boundary when an unconfined aqui...
Rodrick D. Lentz* USDA-ARS Northwest Irrigation and Soils Research Lab. 3793 N 3600 E Kimberly, ID 83341 High water infiltration rates in unlined canals, reservoirs, and the inflow end of furrows relative to outflow ends result in excessive seepage losses and reduced furrow irrigation application uniformity. This study evaluated the use of cross-linked, anionic, polyacrylamide hydrogel (XPAM), ...
The flux of several polycyclic aromatic hydrocarbons (PAHs) from coal tar-impacted river sediment was measured under various seepage rates in a laboratory scale. The batch PAH equilibrium data between aqueous phase (C(eq)) and sediment phase was well-explained using a Raoult's law approach. In the flux measurement from column study, the steady-state PAH concentrations (C(infinity)) in the efflu...
Based on geological information of the Fengman dam, the seepage flow of the dam is analyzed. There are many different affecting factors on seepage problem, for example: the effect of the parameter of concrete, cut-off wall, the permeability coefficient of cut-off wall, drainage hole and grout curtains etc. On the basis of the research, the seepage control mechanism and effectiveness of the seep...
The effects of seepage on streambank erosion and failure are less understood compared to fluvial processes, especially the linkage between surface water and groundwater mechanisms. Field data are needed to validate laboratory seepage erosion and instability conclusions and to understand how engineering tools and methods may be applied to field conditions. An innovative trench injection system w...
We measured groundwater apparent age (s) and seepage rate (v) in a sandy streambed using point-scale sampling and seepage blankets (a novel seepage meter). We found very similar MTT estimates from streambed point sampling in a 58 m reach (29 years) and a 2.5 km reach (31 years). The TTD for groundwater discharging to the stream was best fit by a gamma distribution model and was very similar for...
Despite improved endotracheal tube designs, aspiration remains a cause of pulmonary complications. This in vitro study evaluates the efficacy of positive end-expiratory pressure (PEEP) in reducing the incidence of seepage around endotracheal tubes during mechanical (MV) and spontaneous ventilation (SV). Two transparent plastic "tracheas" with cuffed and uncuffed endotracheal tubes simulated adu...
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