نتایج جستجو برای: erosion rate

تعداد نتایج: 987131  

2008
Michael P. Lamb William E. Dietrich Leonard S. Sklar

[1] A mechanistic model is derived for the rate of fluvial erosion into bedrock by abrasion from uniform size particles that impact the bed during transport in both bed and suspended load. The erosion rate is equated to the product of the impact rate, the mass loss per particle impact, and a bed coverage term. Unlike previous models that consider only bed load, the impact rate is not assumed to...

2013
P. C. Stangeby D. L. Rudakov A. Hassanein

Experimental observation of net erosion of molybdenum being significantly reduced compared to gross erosion in the divertor of DIII-D is reported for well-controlled plasma conditions. For the first time, gross erosion rates were measured by both spectroscopic and non-spectroscopic methods. In one experiment a net erosion rate of 0.73 ± 0.03 nm/s was measured using ion beam analysis (IBA) of a ...

2015
Juan Li Jiawen Qiu Yuchuan Chu Tianping Zhang Wei Meng Yanhui Jia Xiaohui Liu

This article developed an ion thruster optic system sputter erosion depth numerical 3D model by IFE-PIC (Immersed Finite Element-Particle-in-Cell) and Mont Carlo method, and calculated the downstream surface sputter erosion rate of accelerator grid; compared with LIPS-200 life test data. The results of the numerical model are in reasonable agreement with the measured data. Finally, we predicted...

2009
Joseph I. Achebo

This paper clearly explains the use of drift flux models based on Eulerian continuum equations in predicting erosion wear rate in a transmission pipeline. In this case, a pipeline with a diameter of 0.5m was investigated. It was found that there was a large sand particle concentration on the welded parts of the pipe which has affected the internal geometry of the pipe. From physical examination...

1999
THOMAS L. TAYLOR JR.

Understanding tbe temporal response of infiltration rate and interrill erosion to selected livestock grazing strategies is necessary for the continued soil and water conservation of rangeland. Inflltration rate and btterrill erosion were sampled bimontbly from 1978-1984 on pastures grazed continuously (MCG) and moderately stocked (8.1 be AU-r); continuously (I-ICC) and heavily stocked (4.6 ha A...

Erosion caused by sand transportation in flow changing devices is a serious concern in the hydrocarbon and mineral processing industry, which entail to failure and malfunction of flow devices. In this study, computational fluid dynamics (CFD) with discrete phase models (DPM) were employed for analysis of carbon steel long radius 90-Degree elbow erosion due to the sand concentration of 2, 5 and ...

Rill erosion is considered to be the most important process affecting soils created by the concentrated flow of water. In this research to quantify sediment transport and runoff in natural rills, two rill experiments under dry and wet conditions were accomplished in November 2013 in the Golestan Dam. Filed experiments lead to a closer understanding of the dynamics and power of different soil er...

2016
Hilary Ford Angus Garbutt Cai Ladd Jonathan Malarkey Martin W. Skov

BACKGROUND Plants play a pivotal role in soil stabilization, with above-ground vegetation and roots combining to physically protect soil against erosion. It is possible that diverse plant communities boost root biomass, with knock-on positive effects for soil stability, but these relationships are yet to be disentangled. QUESTION We hypothesize that soil erosion rates fall with increased plan...

2006
Gerard H. Roe Drew B. Stolar Sean D. Willett

The theories of critical orogenic wedges and fluvial erosion are combined to explore the interactions between tectonics, erosion, and climate. A model framework is developed which allows the derivation of an exact analytical scaling relationship for how orogen width, height, and rock uplift rate vary as a function of accretionary flux and precipitation rate. Compared to a model with prescribed ...

Journal: :International journal of pharmaceutics 2014
Muhammad U Ghori Gidion Ginting Alan M Smith Barbara R Conway

Hypromellose, HPMC, is frequently used to control drug release from matrix tablet formulations. Drug is released by a combination of diffusion through and erosion of, the matrix and is usually measured invitro by separate dissolution and swelling/erosion studies. The present study was designed to measure matrix erosion, polymer dissolution and drug release kinetics and their inter-relationship ...

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