نتایج جستجو برای: layered gravel

تعداد نتایج: 37400  

2014
Guo Shuai Li Jian Jun Qu Xu Zhi Li Wan Fu Wang

Gravel beds can prevent sand-dust emission and weaken sand-dust flux. We used wind-tunnel experiments and field observations on artificial gravel beds above the Mogao Grottoes to quantify their impact. In the report, we identified a significant correlation between gravel roughness and its ability to trap wind-transported sand. The optimal combinations of gravel diameter and coverage were determ...

2013
Huifang Wang Bo Xiao Mingyu Wang Ming'an Shao

Soil water retention parameters are critical to quantify flow and solute transport in vadose zone, while the presence of rock fragments remarkably increases their variability. Therefore a novel method for determining water retention parameters of soil-gravel mixtures is required. The procedure to generate such a model is based firstly on the determination of the quantitative relationship betwee...

2015
Parneet Paul

Applications of geotextiles within tertiary stormwater treatment systems and for stormwater infiltration can provide a substrate for biofilm formation, enabling biological treatment of contaminants. Geotextiles can serve as an efficient part of stormwater filtration within the urban water environment. The project assessed the applications of three experimental granular filters as a sustainable ...

2011
J. Shulmeister

Contents 1. Introduction 2. Gravelly Beach Morphology 2.1. Gravelly beach profiles 2.2. Berms and the beach step 2.3. Cusps 3. Hydrodynamics of gravel beaches 3.1. Waves 3.2. Swash phase and percolation effects 3.3. Hydrodynamic effects of the beach step 4. Morphosedimentology of Gravel Beaches 4.1. Size and shape sorting 4.2. Measuring gravel size and shape. 4.3. Bluck models of gravel beach s...

Journal: :Computers & Geosciences 2005
Yuichi Hayakawa Takashi Oguchi

Sphericity and roundness have been employed in sedimentological and geomorphological studies to represent the gross shape of a gravel particle. The original complex definitions of gravel sphericity and roundness led to the use of visual charts or simplified parameters. Although the accurate derivation of sphericity requires the surface area of a gravel particle, manual measurement of the area i...

2014
Ryan A. McManamay Donald J. Orth Charles A. Dolloff

Sediment transport, one of the key processes of river systems, is altered or stopped by dams, leaving lower river reaches barren of sand and gravel, both of which are essential habitat for fish and macroinvertebrates. One way to compensate for losses in sediment is to supplement gravel to river reaches below impoundments. Because gravel addition has become a widespread practice, it is essential...

Journal: :European journal of cardio-thoracic surgery : official journal of the European Association for Cardio-thoracic Surgery 2005
Jacques Jougon Antonio Minniti Jean François Velly

A man riding a bike crashed against a bridge and fell into a river. He was rescued just before drowning. Chest radiography and CT scan showed gravel filling almost all his bronchial tree. Three hours were necessary to take out all the gravel by rigid bronchoscopy (Figs. 1 and 2). Fig. 1. Frontal CT scan showing gravel blocking the bronchial tree. Only the right upper bronchus lobe is free. Fig....

2004
P. Ritchie

t The effect of sesquioxidic i i ic gravels (>2 mm size fraction) on phosphorus sorption by two gravelly lateritic soils was investigated by phosphorus sorption experiments, X-ray diffraction, ti , autoradiography and electron microscopy. In one soil the abundance and size of gravels l decreased downslope. As the gravel content of both soils increased (13-61%), ), the proportion of large (>8 mm...

2008
A. MASONI L. ERCOLI M. MARIOTTI S. PAMPANA

Soil gravel content affects many soil physical properties, as well as crop yield. Little is known regarding the influence of soil gravel content on growth and nutrient uptake of durum wheat (Triticum durum Desf.). The accumulation of nitrogen and phosphorous during the vegetative and reproductive periods and the contribution of pre-anthesis assimilates to grain N and P content have been evaluat...

2015
Qing Zeng Linlu Shi Li Wen Junzhu Chen Hairui Duo Guangchun Lei Cédric Sueur

Gravel bars are characteristic components of river landscapes and are increasingly recognized as key sites for many waterbirds, though detailed studies on the ecological function of gravel bars for waterbirds are rare. In this study, we surveyed the endangered Scaly-sided Merganser Mergus squamatus along a 40 km river section of Yuan River, in Central China, for three consecutive winters. We de...

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