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This paper presents an accelerated approach and an automated system for short-term machinability evaluation of metal materials. The proposed approach is developed for ranking materials in terms of machinability. It considers both objective factors, such as machine variables and process outputs, and subjective factors, such as the decision maker's preferences regarding different criteria (objectives, e.g. operation cost, production rate, and product quality). A set of analytical and empirical formulas relevant to different aspects of machinability are identified. A definition of machinability as a function of process outputs is proposed. A method for assessing the weights of importance of different criteria is proposed. Based on the approach, a computer software package called MACPRO for machinability assessment is developed. The computerized machinability evaluation system interfacing with sensors is configured to facilitate data sampling/processing and man/machine interactions. Results of experiments with different work-piece materials for a manufacturing company and problem are analysed and discussed. The results indicate that the approach and designed system are reliable, robust, fast (about half an hour), and easy to implement. The approach is currently being implemented and used in some major metal cutting industries. 相似文献
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文章介绍了对八钢四号板坯连铸机轻压下系统的技术改造和升级。使其除具备了全程动态轻压下功能外,并成功实现了生产过程中根据拉速、温度、钢种等变化随机调整压下位置降低改判率的上业化应用。生产实践表明:优化升级后在低拉速、开停机等情况下得到实现,整个压下过程平稳顺利,辊缝控制精度良好,实施轻压下时铸坯无内部裂纹生成。铸坯内部质量得以明显改善。 相似文献
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The objective of this research was to evaluate the ability of acoustic impulse response for monitoring the mandarin firmness change during storage. The dominant resonant frequency, stiffness coefficient (SC) and elasticity coefficient (EC) decrease with storage time. A good correlation was established between the acoustic parameters (SC and EC) and fruit compression force, and the correlation coefficients were 0.88 and 0.92, respectively. Acoustic impulse response gives a good indication of firmness change for mandarin during storage. The change of EC was more prominent (greatest), and hence it can be a better index of mandarin firmness. The nondestructive acoustic test might replace conventional destructive test for mandarin to determine fruit firmness and expected shelf life. 相似文献
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为评价2-氯乙基磷酸诱导烟碱提前向降烟碱转化的有效性,对湖北和海南两个白肋烟产地的3个白肋烟品种(系)和1个改良品种,进行了2-氯乙基磷酸早期诱导烟碱转化效果研究,并与正常调制的烟叶进行对比分析。结果表明,经过2-氯乙基磷酸处理后,除湖北恩施种植的鄂烟1号外,其余试验品种(系)群体平均烟碱转化率均高于正常调制后的烟叶,其中B21群体平均转化率和高转化株比例高于其它品种;湖北恩施种植的3个品种(系)早期诱导和正常调制在转化株鉴定结果的一致性上比海南高,其中湖北恩施种植的TN90和海南种植的改良鄂烟1号的转化株数超过正常调制出现的转化株数;利用2-氯乙基磷酸早期诱导鉴定筛选留种非转化株,使鄂烟1号后代转化率分别由改良前的22.10%和16.93%降为3.98%,转化株比例尤其是高转化株的比例分别由改良前的48%和27%降为2%。 相似文献
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A way of calculating the overall equivalent heat transfer coefficient of wheel rims of large capacity steam turbines is presented. The method and formula to calculate the mean forced convection heat-transfer coefficient of the surface of the blade and for the bottom wall of the blade passage, are introduced. The heat transmission from the blade to the rim was simplified by analogy to heat transmission in the fins. A fin heat transfer model was then used to calculate the equivalent heat transfer coefficient of the blade passage. The overall equivalent heat transfer coefficient of the wheel rim was then calculated using a cylindrical surface model. A practical calculation example was presented. The proposed method helps determine the heat transfer boundary conditions in finite element analyses of temperature and thermal stress fields of steam turbine rotors. 相似文献
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在对现有传统汽车前雾灯的光源、零部件数量、零部件材料、总成重量等基础上,分析应用PSX24W灯泡作为发光源的理论可行性及实际应用的可行性。突出PSX24W发光源的汽车前雾灯减少了零部件数量,减轻了灯具重量,降低了灯具的功率,实现了减排放、降能耗、节成本的目的。 相似文献