Plastic bags, though commonly used for packaging of goods, are highly durable and non- biodegradable. Plastic bag litter serves as a negative environmental externality detrimental to animal health and natural beauty o...Plastic bags, though commonly used for packaging of goods, are highly durable and non- biodegradable. Plastic bag litter serves as a negative environmental externality detrimental to animal health and natural beauty of the environment. In an effort to curtail the excessive use of plastic bags in Botswana, the government introduced a plastic levy targeted at consumers at retail points. This study uses primary data collected from 367 respondents randomly selected from six geospatially and purposively selected shopping malls to determine the consumers＇ willingness to pay （WTP） for continued plastic bag usage and their willingness to accept （WTA） to shift to eco-friendly alternatives. The results of the study revealed that open dumping and burning of plastic litter are more common in Maun than in Gaborone, It also showed that there is a significant relationship between the level of education and W＇FP. Further, there is a significant variation in income and education in respect to environmental awareness. The government should improve its efforts of sensitizing the public about the improper disposal of plastic bags.展开更多
By axial compression tests on 6 reinforced concrete slender columns wrapped with carbon fiber-reinforced plastic (CFRP),with slenderness ratio(SR) from 4.5 to 17.5,the results show that when SR increases the retrofitt...By axial compression tests on 6 reinforced concrete slender columns wrapped with carbon fiber-reinforced plastic (CFRP),with slenderness ratio(SR) from 4.5 to 17.5,the results show that when SR increases the retrofitting effect declines. In the case of same SR,the stability coefficient (SC) for the reinforced concrete(RC) columns with CFRP is much less than that without CFRP. There is 20% increase of stable bearing capacity to the former as compared with the latter when the SR in less than 17.5. The study summarized the simplified formula for SC,which provides a reference for engineering designers.展开更多
In this paper, the life cycle assessment(LCA) method is used to evaluate and quantify the energy consumption and environmental impacts of biodegradable polylactic acid(PLA) plastic packaging from the five stages of ra...In this paper, the life cycle assessment(LCA) method is used to evaluate and quantify the energy consumption and environmental impacts of biodegradable polylactic acid(PLA) plastic packaging from the five stages of raw material acquisition, raw material transportation, product production, products use and final disposal. Seven impact categories were selected for the impact analysis: abiotic depletion potential fossil fuels(ADP), global warming potential(GWP), acidification potential(AP), eutrophication potential(EP), photochemical ozone formation potential(POCP), human toxicity potential(HTP), and terrestrial ecotoxicity potential(TETP). The results of the LCA are discussed and the results show that production of products is the highest stage of the environmental impact. Meanwhile, in the entire life cycle, the top three environmental impact categories are GWP, ADP and HTP,which account for 32.63%, 24.83% and 14.01%, respectively. The LCA results show that the environmental impact can be reduced in several ways: reducing the consumption of electricity, increasing the input of new energy, increasing the conversion rate of materials in the production process, using organic and water-soluble fertilizers instead of conventional fertilizers, using environment-friendly fuels and establishing a sound recycling system.展开更多
文摘Plastic bags, though commonly used for packaging of goods, are highly durable and non- biodegradable. Plastic bag litter serves as a negative environmental externality detrimental to animal health and natural beauty of the environment. In an effort to curtail the excessive use of plastic bags in Botswana, the government introduced a plastic levy targeted at consumers at retail points. This study uses primary data collected from 367 respondents randomly selected from six geospatially and purposively selected shopping malls to determine the consumers＇ willingness to pay （WTP） for continued plastic bag usage and their willingness to accept （WTA） to shift to eco-friendly alternatives. The results of the study revealed that open dumping and burning of plastic litter are more common in Maun than in Gaborone, It also showed that there is a significant relationship between the level of education and W＇FP. Further, there is a significant variation in income and education in respect to environmental awareness. The government should improve its efforts of sensitizing the public about the improper disposal of plastic bags.
文摘By axial compression tests on 6 reinforced concrete slender columns wrapped with carbon fiber-reinforced plastic (CFRP),with slenderness ratio(SR) from 4.5 to 17.5,the results show that when SR increases the retrofitting effect declines. In the case of same SR,the stability coefficient (SC) for the reinforced concrete(RC) columns with CFRP is much less than that without CFRP. There is 20% increase of stable bearing capacity to the former as compared with the latter when the SR in less than 17.5. The study summarized the simplified formula for SC,which provides a reference for engineering designers.
基金Tianjin Municipal Science and Technology Bureau(17JCYBJC42400)Tianjin Municipal Education Commission(2017KJ020)Tianjin Key Laboratory of Integrated Design and On-line Monitoring for Light Industry&Food Machinery and Equipment 2019(LIMFE08).
文摘In this paper, the life cycle assessment(LCA) method is used to evaluate and quantify the energy consumption and environmental impacts of biodegradable polylactic acid(PLA) plastic packaging from the five stages of raw material acquisition, raw material transportation, product production, products use and final disposal. Seven impact categories were selected for the impact analysis: abiotic depletion potential fossil fuels(ADP), global warming potential(GWP), acidification potential(AP), eutrophication potential(EP), photochemical ozone formation potential(POCP), human toxicity potential(HTP), and terrestrial ecotoxicity potential(TETP). The results of the LCA are discussed and the results show that production of products is the highest stage of the environmental impact. Meanwhile, in the entire life cycle, the top three environmental impact categories are GWP, ADP and HTP,which account for 32.63%, 24.83% and 14.01%, respectively. The LCA results show that the environmental impact can be reduced in several ways: reducing the consumption of electricity, increasing the input of new energy, increasing the conversion rate of materials in the production process, using organic and water-soluble fertilizers instead of conventional fertilizers, using environment-friendly fuels and establishing a sound recycling system.
