نتایج جستجو برای: bottom sediment

تعداد نتایج: 94716  

1999
F. de Rooij S. B. Dalziel P. F. Linden

This paper reports a new technique to measure the thickness of a layer of deposited sediment as a function of time, independent of the flow conditions or presence of suspended sediment above the layer. Small electrodes on the bottom and a reference electrode in the fluid above were used to measure the resistance of the layer with a small AC current and a bridge circuit. Using a multiplexer and ...

2001
G. C. Chang T. D. Dickey A. J. Williams

The present comprehensive physical and optical measurements have captured sediment resuspension associated with two hurricanes, Edouard and Hortense, that passed over the Coastal Mixing and Optics study site in the fall of 1996. Sediment resuspension associated with Hurricane Edouard was forced by combined current and wave processes. Combined current-wave bottom shear stresses exceeded 3.5 dyn ...

M.R Majdzadeh Tabatabai S.H Ghoreishi

Sediment flushing of reservoirs is an operational technique, whereby previously accumulated sediments in the reservoirs are hydraulically removed by accelerated flow when the bottom desiltingoutlets of the dam are opened. In this research, the process of sediment flushing is simulated by a three dimensional numerical model in which sediment and flow interaction are reflected in the reservoirs. ...

2014
Courtney K. Harris

Estimates of sediment concentrations and flux in coastal oceans can help predict optical and acoustical water properties, interpret remotely sensed coastal data, and characterize seafloor morphology. Predicting turbidity requires that we account for processes that erode, supply, and redistribute sediment; including storms, floods, winds, tides, and energetic waves. In many environments, particu...

2010
A. SITI WAZNAH

Bottom sediment samples from Pahang riverestuary were analyzed for the sediment characteristics in order to understand better sedimentation processes in the estuary. The mean, sorting, skewness and kurtosis values of each sample were determined by the Moment’s method. This study showed that the sediment characteristics were not significantly differ (p > 0.05) with the seasonal changes, except f...

2009
MD. ABDUL KARIM KIMIO FUKAMI

Mesophilic Enterobacter strain 9410-O isolated from a eutrophic bottom water environment and introduced into it to enhance heterotrophic activities and decompose organic matters in situ. The bacteria were added as cell suspension after absorbing with porous substrates, like Eco-breath, Neo-coal and Accela35. The strain stimulated net regeneration of dissolved inorganic nitrogen and inorganic ph...

2009
K. E. JURACEK A. C. ZIEGLER

The ability to achieve meaningful decreases in sediment loads to reservoirs requires a determination of the relative importance of sediment sources within the contributing basins. In an investigation of sources of fine-grained sediment (clay and silt) within the Perry Lake Basin in northeast Kansas, representative samples of channel-bank sources, surface-soil sources (cropland and grassland), a...

2010
Lisa M. Zurk

The propagation of mid-frequency (1-10 kHz) acoustic waves in shallow water regions (depths of 100200 m) is strongly influenced by the characteristics of the ocean bottom. While there has been much progress in developing and validating bottom scattering models, much of the focus has been in the high frequency regime with comparatively less focus in the mid-frequency. This is an important topic,...

ژورنال: بوم شناسی آبزیان 2019

Macrobenthos are benthic animals that live in or on the bottom sediments which used as a bioindicators to assess the presence of contaminants, in natural aquatic systems. This study aimed to achieve the relationship between sediment composition and macrobenthic communities, distribution. Sampling was done monthly in 2011-12 by a powerboat, and VanVeen grab with 0.04 cross section, were used for...

Hydro-induction sediment discharge technique (HSDT) aims to prevent reservoir sedimentation by withdrawing the discharge water from the reservoir bottom to suck up and discharge sediments, and by inducing vertical vortexes and undercurrents in the reservoir bay to keep sediments agitated and moving. The technique is facilitated with an innovative discharge conduit system having bottom intakes t...

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