The rheological behavior of semi-solid AZ91D magnesium alloy was investigated in isothermal steady state condition. The effects of stirring temperature and shearing rate on apparent viscosity of semi-solid alloy slurr...The rheological behavior of semi-solid AZ91D magnesium alloy was investigated in isothermal steady state condition. The effects of stirring temperature and shearing rate on apparent viscosity of semi-solid alloy slurry at steady state were discussed. The results show that the apparent viscosity of semisolid AZ91D alloy increases with increasing solid fraction. It increases slightly before the solid fraction reaches a certain value, about 0.4, and then goes up rapidly aider the solid fraction reaches the critical value. However, the apparent viscosity decreases with increasing shearing rate, and the reduction amplitude is higher when the solid fraction is higher. According to the experimental data, an empirical equation that shows the effect of solid fraction and sheafing rate on the apparent viscosity of semi-solid AZ91D alloy can be built as ηa=9.7×10^-2 exp（13.87fs）γ^-0.58.展开更多
Anaerobic co-digestion of food waste（FW） and rice straw（RS） in continuously stirred tank reactor（CSTR） at high organic loading rate（OLR） was investigated. Co-digestion studies of FW and RS with six different m...Anaerobic co-digestion of food waste（FW） and rice straw（RS） in continuously stirred tank reactor（CSTR） at high organic loading rate（OLR） was investigated. Co-digestion studies of FW and RS with six different mixing ratios were conducted at an initial volatile solid（VS） concentration of more than 3 g VS · L-1. The biogas production, methane contents, degradation efficiency of VS, chemical oxygen demand（COD） and volatile fatty acids（VFAs） were determined to evaluate the stability and performance of the system. The results showed that the co-digestion process had higher system stability and higher volumetric biogas production than mono-digestions. Increase in FW content in the feedstock could increase the methane yield and shorten retention time. The efficiency of co-digestion systems mainly relied on the mixing ratios of FW and RS to some extent. The highest methane yield was 60.55 m L· g V· S-1 · d-1 at a mass ratio（FW/RS） of 3 ： 1, which was 178% and 70% higher than that of mono-digestions of FW and RS, respectively. Consequently, the anaerobic co-digestion of FW and RS could have superior stability and better performance than monodigestions in higher organic loading system.展开更多
The electromagnetic-mechanical stirring technology was employed for preparing QTi4.3-4 graghite composite slurry,and QTi4.3-4 graghite composite with uniform distribution of graphite particles was prepared uring the ...The electromagnetic-mechanical stirring technology was employed for preparing QTi4.3-4 graghite composite slurry,and QTi4.3-4 graghite composite with uniform distribution of graphite particles was prepared uring the semi-solid casting technology successfully.The structure of this QTi4.3-4graphite composite was studied and the condition for uniform distribution of graphite particles was got.The experimental results show that there exists a linear relationship between the solid fraction and the stirring temperature of QTi4.3-4graphite slurry.With the decreasing of stirring temperature,the solid fraction of QTi4.3-4 graghite slurry increases constantly.In casting,with the increasing of solid fraction of QTi4.3-4 graphite slurry.the agglomeration of graphite particles is removed gradually.When the solid fraction is higher than 40%,graphite particles can distribute evenly in QTi4.3-4 graghite composite.展开更多
The purpose of this case study was to conduct a case study in the generation rate, composition, and characterise solid wastes from low, middle and high income households during weekdays and weekends in Palapye, Botswa...The purpose of this case study was to conduct a case study in the generation rate, composition, and characterise solid wastes from low, middle and high income households during weekdays and weekends in Palapye, Botswana. The study was conducted through sampling and analysis of the wastes from sampled households from each of the three categories. Palapye village does not have an engineered solid waste management system in place;hence the study can be used as a starting point. The village is rapidly urbanising with many shopping complexes coming up which will generate high amounts of solid wastes of different compositions. The lowest generation rate was 0.038 kg/capita/day from low income households during weekends and the highest was 0.364 kg/capita/day generated from high income households during weekends. The composition of the wastes was dominated by food wastes ranging from 46.44% to 80.78% with low income households generating the highest percentage during weekdays. The average moisture contents of samples from low, middle and high income households were 71% ± 0.0%, 66.3% ± 1.25% and 74.3% ± 2.2% respectively during weekdays compared to 77% ± 0.0%, 66.5% ± 3.5% and 69.3% ± 3.3% during weekends. The average moisture contents from low, middle and high income households were 71% ± 0.0%, 66.3% ± 1.25% and 74.3% ± 2.2% respectively during weekdays compared to 77% ± 0.0%, 66.5% ± 3.5% and 69.3% ± 3.3% during weekends. The results can be used as part of the waste management planning purpose by the Administrative Council of the area.展开更多
基金Funded by the Innovative Group of Science and Technology of College of Jiangxi Province(No.00008713)
文摘The rheological behavior of semi-solid AZ91D magnesium alloy was investigated in isothermal steady state condition. The effects of stirring temperature and shearing rate on apparent viscosity of semi-solid alloy slurry at steady state were discussed. The results show that the apparent viscosity of semisolid AZ91D alloy increases with increasing solid fraction. It increases slightly before the solid fraction reaches a certain value, about 0.4, and then goes up rapidly aider the solid fraction reaches the critical value. However, the apparent viscosity decreases with increasing shearing rate, and the reduction amplitude is higher when the solid fraction is higher. According to the experimental data, an empirical equation that shows the effect of solid fraction and sheafing rate on the apparent viscosity of semi-solid AZ91D alloy can be built as ηa=9.7×10^-2 exp（13.87fs）γ^-0.58.
基金Supported by the Natural Science Foundation of Heilongjiang Province(QC2014C031)Returned Overseas Foundation of Heilongjiang Province(LC2013C07)+2 种基金Outstanding Academic Leaders Foundation of Harbin City(2013RFXYJ015)Young Reserve Talent Foundation of Harbin City(2014RFQYJ141)Outstanding Young Foundation of Heilongjiang Academy of Agricultural Sciences(2013JCQN003)
文摘Anaerobic co-digestion of food waste（FW） and rice straw（RS） in continuously stirred tank reactor（CSTR） at high organic loading rate（OLR） was investigated. Co-digestion studies of FW and RS with six different mixing ratios were conducted at an initial volatile solid（VS） concentration of more than 3 g VS · L-1. The biogas production, methane contents, degradation efficiency of VS, chemical oxygen demand（COD） and volatile fatty acids（VFAs） were determined to evaluate the stability and performance of the system. The results showed that the co-digestion process had higher system stability and higher volumetric biogas production than mono-digestions. Increase in FW content in the feedstock could increase the methane yield and shorten retention time. The efficiency of co-digestion systems mainly relied on the mixing ratios of FW and RS to some extent. The highest methane yield was 60.55 m L· g V· S-1 · d-1 at a mass ratio（FW/RS） of 3 ： 1, which was 178% and 70% higher than that of mono-digestions of FW and RS, respectively. Consequently, the anaerobic co-digestion of FW and RS could have superior stability and better performance than monodigestions in higher organic loading system.
文摘The electromagnetic-mechanical stirring technology was employed for preparing QTi4.3-4 graghite composite slurry,and QTi4.3-4 graghite composite with uniform distribution of graphite particles was prepared uring the semi-solid casting technology successfully.The structure of this QTi4.3-4graphite composite was studied and the condition for uniform distribution of graphite particles was got.The experimental results show that there exists a linear relationship between the solid fraction and the stirring temperature of QTi4.3-4graphite slurry.With the decreasing of stirring temperature,the solid fraction of QTi4.3-4 graghite slurry increases constantly.In casting,with the increasing of solid fraction of QTi4.3-4 graphite slurry.the agglomeration of graphite particles is removed gradually.When the solid fraction is higher than 40%,graphite particles can distribute evenly in QTi4.3-4 graghite composite.
文摘The purpose of this case study was to conduct a case study in the generation rate, composition, and characterise solid wastes from low, middle and high income households during weekdays and weekends in Palapye, Botswana. The study was conducted through sampling and analysis of the wastes from sampled households from each of the three categories. Palapye village does not have an engineered solid waste management system in place;hence the study can be used as a starting point. The village is rapidly urbanising with many shopping complexes coming up which will generate high amounts of solid wastes of different compositions. The lowest generation rate was 0.038 kg/capita/day from low income households during weekends and the highest was 0.364 kg/capita/day generated from high income households during weekends. The composition of the wastes was dominated by food wastes ranging from 46.44% to 80.78% with low income households generating the highest percentage during weekdays. The average moisture contents of samples from low, middle and high income households were 71% ± 0.0%, 66.3% ± 1.25% and 74.3% ± 2.2% respectively during weekdays compared to 77% ± 0.0%, 66.5% ± 3.5% and 69.3% ± 3.3% during weekends. The average moisture contents from low, middle and high income households were 71% ± 0.0%, 66.3% ± 1.25% and 74.3% ± 2.2% respectively during weekdays compared to 77% ± 0.0%, 66.5% ± 3.5% and 69.3% ± 3.3% during weekends. The results can be used as part of the waste management planning purpose by the Administrative Council of the area.
