Evaluation of artisan training in metal silo construction for grain storage in Africa: Impact on uptake,entrepreneurship and income

This study assesses the impact of training sheet metal workers in Kenya on their uptake of learned skills and their income. Fifty-eight artisans trained in the construction of metal silos for hermetic grain storage were compared to a random sample of 123 untrained artisans. Results show that two-thirds of the trained artisans were making the silos, half of these in their own workshops and half as employees. The probability of using the skills learned declined with age but increased with previous experience in technical work. The training did not significantly increase the income of employed artisans, but increased the annual income of those who made the silos in their own workshops by KSh315,173 (about US$3,600). The overall impact could be improved by better targeting of trainees, by using apprenticeships as an alternative mode of training, and by encouraging entrepreneurship through business training and provision of credit.     

“金属材料焊接”课堂改革与创新实践

金属材料焊接课程是焊接技术与自动化专业的专业核心课程之一,该文以现代学徒制试点专业建设为契机进行了课程改革,提出以就业为导向的"三引入"教学内容改革、"三联系"的教学方法与教学手段改革以及突出"四个结合"、树立开放的教育教学观。课程改革效果显著,培养了一支优秀的教学团队。     

Steam as coolant and lubricant in turning of metal matrix composites

Green cutting has become focus of attention in ecological and environmental protection. Steam is cheap, poilution-free and eco-friendly, and then is a good and economical coolant and lubricant. Steam generator and steam feeding system were developed to generate and feed steam. Comparative experiments were carried out in cutting AA6061-15 vol.% SiC （25 p.m particle size）, with cubic boron nitride （CBN） insert KB-90 grade under the conditions of compressed air, oil water emulsion, steam as coolant and lubricant, and dry cutting, respectively. The experimental results show that, with steam as coolant and lubricant, gradual reduction in the cutting force, friction coefficient, surface roughness and cutting temperature values were observed. Further, there was reduction in built up edge formation. It is proved that use of water steam as coolant and lubricant is environmentally friendly.     

金属离子的键参数及其难溶氢氧化物pK_(sp)的定量关联研究

研究了影响难溶金属氢氧化物溶度积 (pKsp)大小的有关因素 ,基于逐步线性回归建立了一个pKsp与有关参数的定量关联模型 随后 ,根据金属离子在周期表中的区域及其结构差异进行了分组建模 ,相关系数R分别达到或接近优级水平 (0 994和 0 981) 对模型进行分析发现 ,影响氢氧化物pKsp 的最重要因素是离子电荷z和半径r     

含重金属离子废水处理中膜过滤工艺的研究与应用

通过对金川集团有限公司冶炼厂含Ni,Co,Cu等重金属离子废水膜过滤处理工艺的工业性实验数据的分析,得到处理该种废水的合理工艺流程、铁铝复配混凝剂配比和最佳投加量以及种植膜过滤器的运行参数。为工程设计提供了依据,成功的运用到了实践中。