نتایج جستجو برای: erosion

تعداد نتایج: 30410  

2012
O. Plé

The internal erosion of soil results from seepage flow. It appears to be the main cause of severe hydraulic failure for dams and dikes. All around the world, 46% of dams present a risk of internal erosion. In France, 70 critical cases have already been detected. When internal erosion is suspected, the delay to failure is hardly predictable. Then, authorities should be able to develop effective ...

Journal: :Caries research 2002
Tanya Mathew Paul S Casamassimo John R Hayes

Acidic soft drinks, including sports drinks, have been implicated in dental erosion with limited supporting data in scarce erosion studies worldwide. The purpose of this study was to determine the prevalence of dental erosion in a sample of athletes at a large Midwestern state university in the USA, and to evaluate whether regular consumption of sports drinks was associated with dental erosion....

Journal: :Computers & Geosciences 2011
Aykut Akgün Necdet Türk

Erosion is one of themost important natural hazard phenomena in theworld, and it poses a significant threat to Turkey in terms of land degredation and desertification. To cope with this problem, we must determine which areas are erosion-prone. Many studies have been carried out and different models and methods have been used to this end. In this study, we used a logistic regression to prepare a...

2002
Renata Chmelová Bořivoj Šarapatka

According to a UN Environment Programme survey, topsoil is eroding faster than it forms on about one third of the world’s cropland, causing an estimated 85 % of the world s land degradation from human activities. Erosion of soil, mainly by water, is also a problem in the Czech Republic where 54 % of arable land is endangered by water erosion. The topic of this article is to describe contemporar...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2007
David R Montgomery

Data drawn from a global compilation of studies quantitatively confirm the long-articulated contention that erosion rates from conventionally plowed agricultural fields average 1-2 orders of magnitude greater than rates of soil production, erosion under native vegetation, and long-term geological erosion. The general equivalence of the latter indicates that, considered globally, hillslope soil ...

2017
Mohammed Thamer AlShahrani Satheesh B Haralur Mohammed Alqarni

Dental erosion is the chemical dissolution of the tooth structure. Factors like eating disorders and gastrointestinal diseases are recognized as intrinsic factors for dental erosion. Advanced stages of dental erosion extensively damage the tooth morphology, consequently affecting both esthetics and functions. Reports indicate the growing prevalence of erosion, and hence knowledge of restorative...

2001
H. Soyama H. Kumano M. Saka

In order to avoid or predict cavitation erosion, it is necessary to know resistance of materials against to cavitation impacts. The cavitation impacts, which are larger than certain threshold level, only affect cavitation erosion of materials. In the present paper, existence of the threshold level was revealed experimentally. The threshold level of material is a new parameter to predict the cav...

2012
Isaac J. Larsen David R. Montgomery

The steep topography of mountain landscapes arises from interactions among tectonic rock uplift, valley incision and landslide erosion on hillslopes. Hillslopes in rapidly uplifting landscapes are thought to respond to river incision into bedrock by steepening to a maximum stable or ‘threshold’ angle1–3. Landslide erosion rates are predicted to increase nonlinearly as hillslope angles approach ...

Soil erosion can be considered as one of the most important obstacles in the way of sustainable development of agriculture and natural resources. The aim of this study is to estimate erosion and sediment yield of basin using Erosion Potential Method, in Gorganrud basin, north of Iran. The main factors in the EPM (slope average percent, erosion, rock and soil resistance, and land-use) were evalu...

شهنواز, یاسر, علی پور, حمید, غلام نیا, اعظم, هاتفی اردکانی, امیرحسین, هاشمی نسب, سیده نگار,

Wind erosion is important in areas with less than 150 mm of rainfall Measuring the extent and severity of wind erosion in many countries, including Iran, there is no station to measure wind erosion sediments and so the deposition estimation methods rely on empirical models so that in many cases there are measurement errors. With estimates wind and water erosion and deposition potential compared...

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