为探究塑料污染对农田土壤团聚体的影响,本研究在全国范围内,针对被塑料污染的土壤和未被塑料污染的土壤进行配对采样,经干筛法和湿筛法测定团聚体组成,利用土壤团聚体稳定性指标[团聚体破坏率(Percentage of aggregate destruction,PAD...为探究塑料污染对农田土壤团聚体的影响,本研究在全国范围内,针对被塑料污染的土壤和未被塑料污染的土壤进行配对采样,经干筛法和湿筛法测定团聚体组成,利用土壤团聚体稳定性指标[团聚体破坏率(Percentage of aggregate destruction,PAD)、平均重量直径(Mean weight diameter,MWD)、几何平均直径(Geometric mean diameter,GMD)和标准化平均重量直径(Normalized mean weight diameter,NMWD)]体系的差异,研究了塑料污染对农田土壤团聚体稳定性的影响。结果表明:从团聚体组成来看,农田土壤塑料输入增加了>5 mm机械稳定性大团聚体比例,降低了<0.25 mm机械稳定性团聚体比例;塑料输入降低了>2 mm水稳性大团聚体比例,增加了<0.053 mm土壤颗粒的比例。农田土壤塑料污染显著增加了机械稳定性团聚体的MWD和GMD,但对水稳性团聚体直径无影响。农田土壤塑料污染显著增加了团聚体的PAD,降低了土壤结构的稳定性。研究表明,农田土壤塑料污染会明显增加土壤大团聚体的机械稳定性,略降低团聚体的水稳定性。展开更多
About 1.3 billion tons of waste is being generated in the world annually. This waste is a cause of various diseases. Open dumping of waste also destroys valuable agricultural land. Various researchers have beneficiall...About 1.3 billion tons of waste is being generated in the world annually. This waste is a cause of various diseases. Open dumping of waste also destroys valuable agricultural land. Various researchers have beneficially used plastic waste in cement concrete and asphalt concrete in the past. This study aims at the use of aggregates, made from different types of plastic waste, as partial replacement of coarse aggregates in asphalt mixes. For this purpose waste is collected from different hospitals of the city. Sorted plastic from the waste consists of 64% low density polyethene, 32% high density polyethene and 4% of polypropylene. Plastic waste is shredded, heated and after cooling, pulverizes manually and mechanically. Specific gravity of plastic aggregates is 0.96. Water absorption and soundness values are 4.68% and 7.68% respectively. Impact, crushing and Loss Angeles values of plastic aggregates are 0.7%, 0.5%, and 1.1% respectively. Replacement of natural aggregates by plastic aggregates in asphalt mixes is done up to 25% with 5% incremental increase. Density of asphalt mixes decreases to 2060 kg/m<sup>3</sup>. Consequently flow increases to 5.73 mm. Maximum stability is at 20% replacement i.e. 34.57 KN. Cost analysis of the study indicates that 205% increase in stability are observed with 219% increase in cost.展开更多
Wrappers of betel nuts, chocolates, chips, hand bags, cold drink bottles and all other forms of plastic create significant environmental and economic problem. They consume massive energy and other natural resources, d...Wrappers of betel nuts, chocolates, chips, hand bags, cold drink bottles and all other forms of plastic create significant environmental and economic problem. They consume massive energy and other natural resources, depleting the environment in various ways. In manufacturing firms, construction industries and products delivery services, use of plastic is a priority to handle and pack things comfortably due to its light weight, cost effectiveness and strength. Plastics cannot be banned as it will result in usage of natural resources like paper, wood at a great extent. It is made up of various chemical elements and is regarded as a highly pestilent material which does not easily degrade in the natural environment after its usage. Waste plastics are made up of Polyethylene, Polystyrene and Polypropylene. Temperature varying between 120℃ - 160℃ gives the softening point of these plastics [5]. They do not produce any toxic gases during heating but the softened plastics have tendency to form a lamination or coating over the aggregate, when it is sprayed over the hot aggregate at 160℃. The main objective of this paper is to discuss the significance of plastic in terms of cost reduction, increase in strength and durability when these plastics are heated and coated upon the aggregates (160℃) to compensate the air voids with plastic and binds with aggregate to provide stability.展开更多
文摘为探究塑料污染对农田土壤团聚体的影响,本研究在全国范围内,针对被塑料污染的土壤和未被塑料污染的土壤进行配对采样,经干筛法和湿筛法测定团聚体组成,利用土壤团聚体稳定性指标[团聚体破坏率(Percentage of aggregate destruction,PAD)、平均重量直径(Mean weight diameter,MWD)、几何平均直径(Geometric mean diameter,GMD)和标准化平均重量直径(Normalized mean weight diameter,NMWD)]体系的差异,研究了塑料污染对农田土壤团聚体稳定性的影响。结果表明:从团聚体组成来看,农田土壤塑料输入增加了>5 mm机械稳定性大团聚体比例,降低了<0.25 mm机械稳定性团聚体比例;塑料输入降低了>2 mm水稳性大团聚体比例,增加了<0.053 mm土壤颗粒的比例。农田土壤塑料污染显著增加了机械稳定性团聚体的MWD和GMD,但对水稳性团聚体直径无影响。农田土壤塑料污染显著增加了团聚体的PAD,降低了土壤结构的稳定性。研究表明,农田土壤塑料污染会明显增加土壤大团聚体的机械稳定性,略降低团聚体的水稳定性。
文摘About 1.3 billion tons of waste is being generated in the world annually. This waste is a cause of various diseases. Open dumping of waste also destroys valuable agricultural land. Various researchers have beneficially used plastic waste in cement concrete and asphalt concrete in the past. This study aims at the use of aggregates, made from different types of plastic waste, as partial replacement of coarse aggregates in asphalt mixes. For this purpose waste is collected from different hospitals of the city. Sorted plastic from the waste consists of 64% low density polyethene, 32% high density polyethene and 4% of polypropylene. Plastic waste is shredded, heated and after cooling, pulverizes manually and mechanically. Specific gravity of plastic aggregates is 0.96. Water absorption and soundness values are 4.68% and 7.68% respectively. Impact, crushing and Loss Angeles values of plastic aggregates are 0.7%, 0.5%, and 1.1% respectively. Replacement of natural aggregates by plastic aggregates in asphalt mixes is done up to 25% with 5% incremental increase. Density of asphalt mixes decreases to 2060 kg/m<sup>3</sup>. Consequently flow increases to 5.73 mm. Maximum stability is at 20% replacement i.e. 34.57 KN. Cost analysis of the study indicates that 205% increase in stability are observed with 219% increase in cost.
文摘Wrappers of betel nuts, chocolates, chips, hand bags, cold drink bottles and all other forms of plastic create significant environmental and economic problem. They consume massive energy and other natural resources, depleting the environment in various ways. In manufacturing firms, construction industries and products delivery services, use of plastic is a priority to handle and pack things comfortably due to its light weight, cost effectiveness and strength. Plastics cannot be banned as it will result in usage of natural resources like paper, wood at a great extent. It is made up of various chemical elements and is regarded as a highly pestilent material which does not easily degrade in the natural environment after its usage. Waste plastics are made up of Polyethylene, Polystyrene and Polypropylene. Temperature varying between 120℃ - 160℃ gives the softening point of these plastics [5]. They do not produce any toxic gases during heating but the softened plastics have tendency to form a lamination or coating over the aggregate, when it is sprayed over the hot aggregate at 160℃. The main objective of this paper is to discuss the significance of plastic in terms of cost reduction, increase in strength and durability when these plastics are heated and coated upon the aggregates (160℃) to compensate the air voids with plastic and binds with aggregate to provide stability.
