The use of recycled concrete and oyster shells as partial cement and aggregate replacements is ongoing research to solve this multifaceted problem of concrete waste in the construction industry as well as waste from o...The use of recycled concrete and oyster shells as partial cement and aggregate replacements is ongoing research to solve this multifaceted problem of concrete waste in the construction industry as well as waste from oyster shell farming. However, there is a lack of evidence on the possibility of producing a fully recycled composite consisting of recycled concrete and oyster shell without the need for new cement and natural aggregates. In this study, recycled concrete powder (RCP) and oyster shell were used to produce a green composite. Separate ground and combined ground (separate ground and co-ground) RCP and oyster shells are used to determine the effects of grinding approaches on the mechanical and chemical properties of the composite. The composite samples were molded via press molding by applying 30 MPa of pressure for 10 minutes. The results revealed that the composite prepared via the combined ground approach presented the highest flexural strength compared to the separate ground and unground samples. The FTIR and XRD characterization results revealed no chemical or phase alterations in the raw materials or the resulting composites before and after grinding. SEM analysis revealed that combined grinding reduced the particles’ size and improved the dispersion of the mixture, thereby increasing the strength.展开更多
Increasing concern over the amount of insecticide residues in food has encouraged research for ecologically sound strategies to effectively manage stored-product insect pests and protect living organisms and the envir...Increasing concern over the amount of insecticide residues in food has encouraged research for ecologically sound strategies to effectively manage stored-product insect pests and protect living organisms and the environment. Botanicals were evaluated as potential alternatives to control maize weevil, Sitophilus zeamais Motschulsky, in stored sorghum, Sorghum bicolor (L.) Moench. Beetles and moths of stored grain at farm and consumer levels damage 5 - 35% worldwide and >40% in tropical countries. Maize weevil is the most damaging storage insect of sorghum grain. Management of storage insects relies on insecticides that leave residues in food and the environment. Treatments were powders of neem bark, Azadirachta indica;mesquite pods, Prosopis glandulosa;milkweed leaves, Asclepias speciosa;and a check (no botanical powder). Eight newly emerged maize weevils were provided 5 g of Malisor-84 grain treated with three doses of each plant powder. Every 2 days, data were recorded on the number of adults killed by each treatment. Percentage killed was calculated by dose per treatment and compared with the check. Grain loss was calculated based on initial and final weights. LD50 was determined by probit analysis, and associations between variables were assessed by simple linear correlation. Powder of mesquite and milkweed at 0.2 g were more effective than neem or the check in killing S. zeamais (>90%) and reducing grain damage (34 - 35.2%) and weight loss (0.8%). Milkweed at 0.1 g and neem at 0.2 g killed 78.1% of weevils. Neem at 0.05 g was slow acting, resulting in 62.5% dead and more grain damage (59.5%) and weight loss (3.6%). Botanicals at low doses (LD50 = 0.2 - 0.4 g) showed efficacy in controlling maize weevils and are recommended alternatives to guarantee quantity and quality of stored cereal grains.展开更多
[Objective] The aim was to research property of maca and three plants＇ powders and process parameters of compound maca direct compression. [Method] Based on analysis data from SAS, bulk density, tap density, angle of...[Objective] The aim was to research property of maca and three plants＇ powders and process parameters of compound maca direct compression. [Method] Based on analysis data from SAS, bulk density, tap density, angle of repose and swelling of powders were studied as per single factor method and orthogonal exper- imental design. [Result] The test indicated that fillibilities of plant A and B, and maca powders are better and flowability plays an important role in fractional close of compound maca powder; plant A and B powders have a significant effect on bulk density of maca （P=0.0125）, an extremely significant effect on swelling volume ratio （P=0.008 9） and little effect on tap density （g/ml）; the optimal process condition of compound maca powder is as follows： A at 0.15 share; B at 0.10 share; C at 0.05 share; the optimal swelling volume ratio is at 2.459. [Conclusion] The technology is reasonable in formulation and satisfactory in fillibility, swelling ability, flowability, and it could serve as theoretical basis for the industrial production of maca tablets.展开更多
增材制造技术(additive manufacturing,AM)的发展为高熔点难熔金属(如钨、钼、钽、铌及其合金)复杂构件的近净成形带来了革命性的新机遇。然而,难熔金属材料因熔点高等固有属性,使其增材制造过程呈现出显著有别于其他金属材料的特殊性...增材制造技术(additive manufacturing,AM)的发展为高熔点难熔金属(如钨、钼、钽、铌及其合金)复杂构件的近净成形带来了革命性的新机遇。然而,难熔金属材料因熔点高等固有属性,使其增材制造过程呈现出显著有别于其他金属材料的特殊性。本文基于激光选区熔化(selective laser melting,SLM)和电子束选区熔化(selective electron beam melting,SEBM)等金属粉末床熔融(powder bed fusion,PBF)增材制造技术,系统综述了钨、钼、钽、铌及其合金在增材制造领域的研究进展。重点聚焦于难熔金属粉末原料制备技术,以及成形过程中工艺缺陷(如孔隙率、裂纹、晶粒粗化等)调控策略和组织性能特点。此外,本文还总结了当前增材制造难熔金属在产业化进程中面临的关键挑战,并对未来发展趋势进行了展望。展开更多
文摘The use of recycled concrete and oyster shells as partial cement and aggregate replacements is ongoing research to solve this multifaceted problem of concrete waste in the construction industry as well as waste from oyster shell farming. However, there is a lack of evidence on the possibility of producing a fully recycled composite consisting of recycled concrete and oyster shell without the need for new cement and natural aggregates. In this study, recycled concrete powder (RCP) and oyster shell were used to produce a green composite. Separate ground and combined ground (separate ground and co-ground) RCP and oyster shells are used to determine the effects of grinding approaches on the mechanical and chemical properties of the composite. The composite samples were molded via press molding by applying 30 MPa of pressure for 10 minutes. The results revealed that the composite prepared via the combined ground approach presented the highest flexural strength compared to the separate ground and unground samples. The FTIR and XRD characterization results revealed no chemical or phase alterations in the raw materials or the resulting composites before and after grinding. SEM analysis revealed that combined grinding reduced the particles’ size and improved the dispersion of the mixture, thereby increasing the strength.
文摘Increasing concern over the amount of insecticide residues in food has encouraged research for ecologically sound strategies to effectively manage stored-product insect pests and protect living organisms and the environment. Botanicals were evaluated as potential alternatives to control maize weevil, Sitophilus zeamais Motschulsky, in stored sorghum, Sorghum bicolor (L.) Moench. Beetles and moths of stored grain at farm and consumer levels damage 5 - 35% worldwide and >40% in tropical countries. Maize weevil is the most damaging storage insect of sorghum grain. Management of storage insects relies on insecticides that leave residues in food and the environment. Treatments were powders of neem bark, Azadirachta indica;mesquite pods, Prosopis glandulosa;milkweed leaves, Asclepias speciosa;and a check (no botanical powder). Eight newly emerged maize weevils were provided 5 g of Malisor-84 grain treated with three doses of each plant powder. Every 2 days, data were recorded on the number of adults killed by each treatment. Percentage killed was calculated by dose per treatment and compared with the check. Grain loss was calculated based on initial and final weights. LD50 was determined by probit analysis, and associations between variables were assessed by simple linear correlation. Powder of mesquite and milkweed at 0.2 g were more effective than neem or the check in killing S. zeamais (>90%) and reducing grain damage (34 - 35.2%) and weight loss (0.8%). Milkweed at 0.1 g and neem at 0.2 g killed 78.1% of weevils. Neem at 0.05 g was slow acting, resulting in 62.5% dead and more grain damage (59.5%) and weight loss (3.6%). Botanicals at low doses (LD50 = 0.2 - 0.4 g) showed efficacy in controlling maize weevils and are recommended alternatives to guarantee quantity and quality of stored cereal grains.
基金Supported by Special Funds of National Technological and Basic Work(2006FY110700)Yunnan Province Improvement Project(2007C0219Z)Special Funds of Biological Industry of Yunnan Financial Development([2011]274)~~
文摘[Objective] The aim was to research property of maca and three plants＇ powders and process parameters of compound maca direct compression. [Method] Based on analysis data from SAS, bulk density, tap density, angle of repose and swelling of powders were studied as per single factor method and orthogonal exper- imental design. [Result] The test indicated that fillibilities of plant A and B, and maca powders are better and flowability plays an important role in fractional close of compound maca powder; plant A and B powders have a significant effect on bulk density of maca （P=0.0125）, an extremely significant effect on swelling volume ratio （P=0.008 9） and little effect on tap density （g/ml）; the optimal process condition of compound maca powder is as follows： A at 0.15 share; B at 0.10 share; C at 0.05 share; the optimal swelling volume ratio is at 2.459. [Conclusion] The technology is reasonable in formulation and satisfactory in fillibility, swelling ability, flowability, and it could serve as theoretical basis for the industrial production of maca tablets.
文摘增材制造技术(additive manufacturing,AM)的发展为高熔点难熔金属(如钨、钼、钽、铌及其合金)复杂构件的近净成形带来了革命性的新机遇。然而,难熔金属材料因熔点高等固有属性,使其增材制造过程呈现出显著有别于其他金属材料的特殊性。本文基于激光选区熔化(selective laser melting,SLM)和电子束选区熔化(selective electron beam melting,SEBM)等金属粉末床熔融(powder bed fusion,PBF)增材制造技术,系统综述了钨、钼、钽、铌及其合金在增材制造领域的研究进展。重点聚焦于难熔金属粉末原料制备技术,以及成形过程中工艺缺陷(如孔隙率、裂纹、晶粒粗化等)调控策略和组织性能特点。此外,本文还总结了当前增材制造难熔金属在产业化进程中面临的关键挑战,并对未来发展趋势进行了展望。
