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网页Sand and gravel are key components for a number of industries—especially construction and coastal protection/restoration—and are major marine extractable resources. The commercial mining of gravel, sand, and related minerals (Baker et al., 2014) is generally 网页2018年9月4日 GP. Various amount of gravel particles (0, 15, 30, 45, 60, 75, 90 and 100 w.t.%) were added to the base sand to achieve different mass proportions between sand 网页2016年6月3日 The maximum and minimum void ratios ( emax and emin) for sand in the SP series were 0.638 and 0.446, respectively, and those for gravel were 0.570 and 0.465, 网页2021年12月5日 沙堆效应”（The sand effect）是由美国学者巴克提出的一种理论，寓意为压死骆驼的最后一根稻草。在研究中，巴克等开始堆沙实验，同时借助慢速录像机和计算机精确地计算每在沙堆顶部落下一粒沙子 网页1941年12月1日 Field practice has shown thatthe screening effect of a given gravel for a given sand apparently varies withthe flow velocity. 2 Also, it has been assumed by some 网页2021年5月1日 Effect of Gravel-Sand Substrate on Sub-Surface Flow Constructed Wetland for Palm Oil Mill Effluent Treatme. nt.pdf. Content available from CC BY 3.0: 网页2021年3月10日 Therefore, the skeleton void ratio index introduced by Chang et al (2015) is revisited to account for the effect of GSD of both gravel and sand grains. Two semi-empirical equations are developed 网页Effects of gravel-sand mulching and irrigation on soil hydrothermal conditions and fruit yield in ecological jujube forests on degraded field 投稿时间：2022-03-17 DOI ： 网页2022年8月30日 Irregular particle shape and particle breakage are the two most important factors affecting the mechanical behavior of rockfill materials [4, 54, 69].Thus, it is 网页The effect of mining is compounded by the effect of sea level rise. Any volume of sand exported from streambeds and coastal areas is a loss to the system. Sand and gravel 网页Sand and gravel are key components for a number of industries—especially construction and coastal protection/restoration—and are major marine extractable resources. The commercial mining of gravel, sand, and related minerals (Baker et al., 2014) is generally restricted to shallow waters within national EEZs. 网页Field practice has shown thatthe screening effect of a given gravel for a given sand apparently varies withthe flow velocity. 2 Also, it has been assumed by some operators that thethickness of the walls of the gravel envelope surrounding the well has littleeffect upon the screening process. It is thought by others that a narrowenvelope of 网页2018年11月16日 Sand and gravel represent about 79% of this material extraction, almost 29 billion tonnes a year, exceeding fossil fuels and biomass extraction. Nations now mine about 13 billion tonnes of sand 网页Effects of gravel-sand mulching and irrigation on soil hydrothermal conditions and fruit yield in ecological jujube forests on degraded field 投稿时间：2022-03-17 DOI ： 10.13254/j.jare.2022.0133 中文关键词: 覆砂，灌水量，土壤水热，枣树生长，产量 英文关键 网页2020年6月23日 Gravel mulching is a characteristic agricultural technique that has been used for hundreds of years in the north-western Loess Plateau of China. However, the effects of the gravel-sand mulch on the processes of the runoff, soil erosion, and nutrient losses are neither fully distinguished nor even known in many parts of the world. This 网页2022年9月10日 The effects of river sand mining can also be seen at the coast where the lack of sand replenishment can cause beaches and dunes to erode faster and therewith offer less protection against storm surges, tsunamis and sea level rise ( Shaghude et al., 2012 ). 5. Effects on the biological environment. 网页The effect of mining is compounded by the effect of sea level rise. Any volume of sand exported from streambeds and coastal areas is a loss to the system. Sand and gravel represent the highest volume of raw material used on earth after water. Their use greatly exceeds natural renewal rates. Moreover, the amount being mined is increasing 网页2023年1月20日 extraction of sand, gravel and other materials exceeds the rate of deposition. Sand budget of a particular environment shall be observed before sand mining. Specific hydrologic Beach erosion takes place because of sand mining and effect homes and livelihoods (Photo-2). Photo- 1. Illegal sand mining in a beach, source: 网页The results of the tests indicate that depositional method has a significant effect on Gmax that this effect was more pronounced for the pure sand specimens than for the pure gravel or sand-gravel mixture specimens. However, the depositional method had no significant effect on the shear modulus at large shear strain amplitudes. 网页Mulch had no further effect on soil temperature when thickness is greater than 7 cm. With 80% plastic film mulch, a significant effect on watermelon yield and WUE was detected among the different treatments used in this study, with the highest yield and WUE obtained with the 8 cm mulch thickness treatment. 网页Field practice has shown thatthe screening effect of a given gravel for a given sand apparently varies withthe flow velocity. 2 Also, it has been assumed by some operators that thethickness of the walls of the gravel envelope surrounding the well has littleeffect upon the screening process. It is thought by others that a narrowenvelope of 网页2018年11月16日 Sand and gravel represent about 79% of this material extraction, almost 29 billion tonnes a year, exceeding fossil fuels and biomass extraction. Nations now mine about 13 billion tonnes of sand 网页2003年9月9日 Abstract. Gravel packing is one of the sand control techniques effectively used in oilfields with unconsolidated formation. The technique most widely used for selecting a suitable sized gravel to control the production of formation sand was developed by Saucier. With this technique, however, no consideration is given to the size distribution of 网页The gravel-sand mulch improved soil-water conditions because it was effective in reducing evaporation and enhancing transpiration. The gravel-sand mulch also improved infiltration of rainwater. For the 0–20 cm soil layers the average temperature in the gravel-sand mulch field was 1.0–5.3°C larger than that in the no-mulch field. 网页2019年12月24日 Effects of gravel-sand mulch, plastic mulch and ridge and furrow rainfall harvesting system combinations on water use efficiency, soil temperature and watermelon yield in a semi-arid Loess Plateau 网页2022年11月22日 Simulating the effect of gravel sand mulched field degradation on soil temperature and evaporation. Journal of Desert Research, 30(2): 388–393. (in Chinese) Wang Y J, Xie Z K, Malhi S S, et al. 2008. Effects of rainfall harvesting and mulching technologies on water use efficiency and crop yield in the semi-arid Loess Plateau, China 网页2017年11月9日 Effects of gravel-sand mulching on soil bacterial community and metabolic capability in the semi-arid Loess Plateau, China World J Microbiol Biotechnol. 2017 Nov 9 Gravel and sand mulching is an indigenous technology used for the crop yield for at least 300 years in the loess area of northwest China; however, little is known about the 网页2020年8月21日 The increase in the demand for sand and gravel for construction and other purposes such as flood control has placed immense pressure on the environment where sand and gravel resources occur. This study was carried out to determine the environmental effects of sand and gravel mining in Luku, North central Nigeria, using field observations 网页2023年1月20日 extraction of sand, gravel and other materials exceeds the rate of deposition. Sand budget of a particular environment shall be observed before sand mining. Specific hydrologic Beach erosion takes place because of sand mining and effect homes and livelihoods (Photo-2). Photo- 1. Illegal sand mining in a beach, source: 网页The results of the tests indicate that depositional method has a significant effect on Gmax that this effect was more pronounced for the pure sand specimens than for the pure gravel or sand-gravel mixture specimens. However, the depositional method had no significant effect on the shear modulus at large shear strain amplitudes.
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