نتایج جستجو برای: and gravel r2085
تعداد نتایج: 16827935 فیلتر نتایج به سال:
Twenty-eight coupled observations of flow, transport, and bed surface grain size distribution were made in a laboratory flume using a wide range of flows and a sediment with a very poorly sorted, bimodal grain size distribution. These observations permit the transport rates of individual size fractions to be scaled by the proportion of each size immediately available for transport on the bed su...
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abstract to study the effects of four types of mulches including wood chips, municipal compost, sawdust and gravel in three different thicknesses on growth of platanus orientalis during two years, an experiment was conducted in mashhad area with semi-arid climate. the research was conducted as split plot based on a completely randomized block design with four replications. treatments included c...
Exclusion and not using of rangeland in the long term affects the composition and homogeneity of vegetation and consequently leads to the improvement of plants status. In this study, the characteristics and structural changes of the rangeland of Gonbad, Hamadan province, Iran, in 2014 (after 20 years of enclosure) were evaluated using Braun-Blanquet plot, Phytosociology and multivariate analysi...
To investigate hydrodynamic processes above and within river beds, laboratory experiments have been performed to quantify the interaction between turbulent flow and pressure fluctuations at a porous gravel bed. A 2-D Particle Image Velocimetry (PIV) system measuring in streamwise vertical or horizontal planes above the gravel layer was used, synchronized with a pressure sensor array of 16 minia...
Sand and gravel mining from the most of our country rivers causes morphological, hydrological and geomorphological changes in these rivers. This study investigates the effects of removal of sand and gravel from the river bed on sedimentological features of Zaremrood River in Mazandaran province. For this purpose, by determining four sections before and four sections after the sand removing poin...
River bed sand and gravel are utilized more than mountain materials due to their availability and closeness to the transit roads and sites of usage. Excessive and non-technical extraction of gravel and sand bring a kind of interference in them, leading to many negative consequences. Therefore, presenting solutions to reduce these impacts and infilling mining pits are essential. In this researc...
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