Feather, as a by-product of the poultry industry, has long been treated as a solid waste, which causes environ- mental and economic problems. In this work, the hydrolyzed feather keratin （HFK） was extracted from the...Feather, as a by-product of the poultry industry, has long been treated as a solid waste, which causes environ- mental and economic problems. In this work, the hydrolyzed feather keratin （HFK） was extracted from the chicken feather using a cost-effective method of alkali-extraction and acid-precipitation by applying urea and sodium sulfide. The aim was development and characterization of the eco-friendly films based on the HFK with variable glycerol contents by a thermoplastic process. The thermal analysis showed that high temperature and high pres- sure improved the compatibility between the glycerol and the HFI（ molecules. Also it was shown that the addi- tion of water is necessary in the hot-pressing process of films, The FT-IR analysis indicated that the formation of the new hydrogen bonds between HFK and glycerol. By increasing the glycerol content, the film tensile strength （orb ） decreases from 10,5 MPa to 5.7 MPa and the solubility increases from 15.3% to 20.9%, while the elongation at break （εb） achieves the maximum value of 63,8% for the film with 35% glycerol. The swelling was just below 16.9% at 25 ℃ for 24 h, suggesting a good stability of the films in water. The water vapor permeability （WVP） varied between 3.02 x 10 ^10g. m 2. s-1 . pa-1 and 4.11 x 10-10g · m-2 · s-1 · Pa-1 for the films with 20%and 40% glycerol, respectively. The HFK film was uniform, translucent and tough, which could be used in packaging and agricultural field.展开更多
This research describes a series of laboratory tests performed to characterize the mechanical properties of plastic concrete. The mechanical properties of plastic concrete are studied using a series of compression tes...This research describes a series of laboratory tests performed to characterize the mechanical properties of plastic concrete. The mechanical properties of plastic concrete are studied using a series of compression tests. Stress relaxation and controlled rate of loading tests are also performed to investigate the rate sensitivity and time-dependency of plastic concrete. An important requirement for the plastic concrete in such applications is adequate strength for the design loads. The replacement of cement content of plastic concrete by micro silica does not result in any significant decrease in workability of plastic concretes and hence, unlike the case for normal concretes, plasticizers or super plasticizers are not required to rectify the adverse effect of micro silica on workability. The aim of the experimental research was to investigate the effects of various levels of cement replacement by micro silica, including 0%, 3%, 6%, 9%, 12% and 15% on strength of plastic concrete. Obtained results show that the effect of micro silica on strength enhancement of plastic concretes is substantial and a replacement level of 15% resulted in 70%-180% increase in strength compared to the control mix. For normal concretes, the increase in strength due to incorporation of micro silica was generally reported as 30%-50%.展开更多
Water-saving irrigation methods have been increasingly used for vegetable cultivation in greenhouse or plastic film house. However, there is limited information concerning the effect of water-saving irrigation methods...Water-saving irrigation methods have been increasingly used for vegetable cultivation in greenhouse or plastic film house. However, there is limited information concerning the effect of water-saving irrigation methods on soil phosphorus （P） behavior. In this experiment, drip and subsurface irrigation methods were applied, with furrow irrigation method as control, in Mollic Gleysols. Soil P distribution throughout the depth was significantly affected by irrigation methods. Total, Olsen, organic and inorganic P contents were greater in the topsoil （0-10 and 10-20 cm） than in the subsoil （20-30, 30-40, 40-50 and 50-60 cm）. The Olsen P content throughout 0-60 cm layer under drip and subsurface irrigation treatments was lower than that under the furrow irrigation treatment. However, the total, organic and inorganic P contents from 20 to 60 cm under drip irrigation treatment were higher than or close to those under furrow irrigation treatment, but were lower under subsurface irrigation treatment than under furrow irrigation treatment. Under subsurface irrigation treatment, the contents of total, organic and inorganic P at the 0-10 cm layer were 78.0%, 1.3% and 3.7% greater than those at the 10-20 cm layer, respectively. But Olsen P content at the 10-20 cm layer was 5.7% larger than that at the 0-10 cm layer. These suggested that soil P behavior could be manipulated by soil water management to some extent. 在展开更多
基金Supported by the National Natural Science Foundation of China(21176269,31371880,31401526)Higher School Science and Technology Innovation Project of Guangdong Province(2013KJCX0102)Science and Technology Plan Project of Guangdong Province(2013B010403029)
文摘Feather, as a by-product of the poultry industry, has long been treated as a solid waste, which causes environ- mental and economic problems. In this work, the hydrolyzed feather keratin （HFK） was extracted from the chicken feather using a cost-effective method of alkali-extraction and acid-precipitation by applying urea and sodium sulfide. The aim was development and characterization of the eco-friendly films based on the HFK with variable glycerol contents by a thermoplastic process. The thermal analysis showed that high temperature and high pres- sure improved the compatibility between the glycerol and the HFI（ molecules. Also it was shown that the addi- tion of water is necessary in the hot-pressing process of films, The FT-IR analysis indicated that the formation of the new hydrogen bonds between HFK and glycerol. By increasing the glycerol content, the film tensile strength （orb ） decreases from 10,5 MPa to 5.7 MPa and the solubility increases from 15.3% to 20.9%, while the elongation at break （εb） achieves the maximum value of 63,8% for the film with 35% glycerol. The swelling was just below 16.9% at 25 ℃ for 24 h, suggesting a good stability of the films in water. The water vapor permeability （WVP） varied between 3.02 x 10 ^10g. m 2. s-1 . pa-1 and 4.11 x 10-10g · m-2 · s-1 · Pa-1 for the films with 20%and 40% glycerol, respectively. The HFK film was uniform, translucent and tough, which could be used in packaging and agricultural field.
文摘This research describes a series of laboratory tests performed to characterize the mechanical properties of plastic concrete. The mechanical properties of plastic concrete are studied using a series of compression tests. Stress relaxation and controlled rate of loading tests are also performed to investigate the rate sensitivity and time-dependency of plastic concrete. An important requirement for the plastic concrete in such applications is adequate strength for the design loads. The replacement of cement content of plastic concrete by micro silica does not result in any significant decrease in workability of plastic concretes and hence, unlike the case for normal concretes, plasticizers or super plasticizers are not required to rectify the adverse effect of micro silica on workability. The aim of the experimental research was to investigate the effects of various levels of cement replacement by micro silica, including 0%, 3%, 6%, 9%, 12% and 15% on strength of plastic concrete. Obtained results show that the effect of micro silica on strength enhancement of plastic concretes is substantial and a replacement level of 15% resulted in 70%-180% increase in strength compared to the control mix. For normal concretes, the increase in strength due to incorporation of micro silica was generally reported as 30%-50%.
基金Supported by the Liaoning Provincial Education Commission,China(No.413101206)
文摘Water-saving irrigation methods have been increasingly used for vegetable cultivation in greenhouse or plastic film house. However, there is limited information concerning the effect of water-saving irrigation methods on soil phosphorus （P） behavior. In this experiment, drip and subsurface irrigation methods were applied, with furrow irrigation method as control, in Mollic Gleysols. Soil P distribution throughout the depth was significantly affected by irrigation methods. Total, Olsen, organic and inorganic P contents were greater in the topsoil （0-10 and 10-20 cm） than in the subsoil （20-30, 30-40, 40-50 and 50-60 cm）. The Olsen P content throughout 0-60 cm layer under drip and subsurface irrigation treatments was lower than that under the furrow irrigation treatment. However, the total, organic and inorganic P contents from 20 to 60 cm under drip irrigation treatment were higher than or close to those under furrow irrigation treatment, but were lower under subsurface irrigation treatment than under furrow irrigation treatment. Under subsurface irrigation treatment, the contents of total, organic and inorganic P at the 0-10 cm layer were 78.0%, 1.3% and 3.7% greater than those at the 10-20 cm layer, respectively. But Olsen P content at the 10-20 cm layer was 5.7% larger than that at the 0-10 cm layer. These suggested that soil P behavior could be manipulated by soil water management to some extent. 在
