排序方式: 共有101条查询结果,搜索用时 257 毫秒
51.
Productive efficiency of public and private solid waste logistics and its implications for waste management policy 总被引:1,自引:0,他引:1
This paper measures the productive efficiency of municipal solid waste (MSW) logistics by applying data envelopment analysis (DEA) to cross-sectional data of prefectures in Japan. Either through public operations or by outsourcing to private waste collection operators, prefectural governments possess the fundamental authority over waste processing operations in Japan. Therefore, we estimate a multi-input multi-output production efficiency at the prefectural level via DEA, employing several different model settings. Our data classify the MSW into household solid waste (HSW) and business solid waste (BSW) collected by both private and public operators as separate outputs, while the numbers of trucks and workers used by private and public operators are used as inputs. The results consistently show that geographical characteristics, such as the number of inhabited remote islands, are relatively more dominant factors for determining inefficiency. While the implication that a minimum efficient scale is not achieved in these small islands is in line with the literature suggesting that waste logistics has increasing returns at the municipal level, our results indicate that waste collection efficiency in Japan is well described by CRS technology at the prefectural level. The results also show that prefectures with higher private-sector participation, measured in terms of HSW collection, are more efficient, whereas a higher private–labor ratio negatively affects efficiency. We also provide evidence that prefectures with inefficient MSW logistics have a higher tendency of suffering from the illegal dumping of industrial waste. 相似文献
52.
53.
54.
55.
Q345R钢是普通低合金高强度钢,广泛的用于压力容器制造行业。其S、P含量控制较严,焊接性较好,但是由于含有一定量的合金元素,淬硬、冷裂倾向都比低碳钢大一些。通过船用氮气储存罐的筒体和封头环焊缝的焊接,分析了Q345R钢的化学成分和机械性能,通过选用合理的焊接材料、坡口形式、焊接方法、焊接工艺来保证储存罐的焊缝质量。 相似文献
56.
为适应铁路快速发展战略的要求,提高铁路货车的运煤能力,株洲车辆厂研制了载重80t不锈钢及全钢运煤敞车。现介绍这种新型运煤敞车的技术参数及尺寸、基本结构、研制过程及其效益分析。 相似文献
57.
58.
80C196MC单片机控制永磁无刷直流电动机调速系统 总被引:1,自引:1,他引:0
扼要地介绍了80C196MC单片机的特点及在永磁无刷直流电动机驱动中的应用。 相似文献
59.
周安德 《电力机车与城轨车辆》2003,26(5):34-36,41
以16位单片机80C196MC为主控制器,采用实时的算法,用MCS96汇编语言编写程序,在ICES-16仿真器上成功实现实时的PWM仿真。 相似文献
60.