探讨火力发电厂环保设备的管理及应用

对于火力发电厂来说,其在日常运行中必须要遵循安全、高效的规范与原则。为满足这一需求,需要保障火力发电厂内相关设备运行的稳定性和可靠性,提高火力发电厂的社会价值与经济效益。如今,随着国家对环境保护工作的重视程度不断提高,火力发电厂内环保设备的管理和应用已经成为社会各界所关注的重点内容。对此,论文主要对火力发电厂环保设备的管理与应用进行分析,以供参考。     

S355J2板带表裂的分析与改善

通过对缺陷钢卷理化检验结果的分析以及生产对比试验,指出连铸坯的角部横向裂纹是板带发生表裂的直接原因。并由此分析了板坯角部横向裂纹产生的主要原因。根据实际工艺条件,采取针对性的改善措施后,板卷表裂缺陷得以有效控制。     

Sewer plant operating efficiency,patronage, and competition

Sewer treatment plants in New York State, US, are studied for efficiency and economies of scale. Substantial economies of scale are found. The degree of inefficiency for each plant is then computed and this inefficiency is related to the degree of market concentration in that county. The result found is that greater concentration induces a reduction in efficiency. This is argued to be consistent with the Tiebout Hypothesis. Copyright © 2004 John Wiley & Sons, Ltd.     

基于Super-SBM模型的污水厂投资效率实证分析

随着我国对污水处理行业投资的不断增长,污水厂建设也得到了迅速的发展。由于污水厂建设具有投资规模大、投资周期长等特点,研究污水厂投资效率具有重要意义。本文针对传统的CCR模型没有考虑投入要素"松弛"和无法解决有效单元排序问题,运用Super-SBM模型对河南省新建13座污水厂投资效率进行了评价。结果表明:污水厂平均投资效率较高,但在建设单位管理费、征地移民、人员培训、勘察设计方面仍存在浪费资金现象。     

Economic Structure and Local Growth: France, 1984–1993

For 52 industry sectors and 42 services sectors, this paper tests how the local economic structure (local sectoral specialization and diversity, competition, average size of plants, and total employment density) affects the 1984–1993 employment growth of 341 local areas. These areas entirely and continuously cover the French territory. The impact of the local economic structure differs in industry and services. In industrial sectors, local total employment density, competition, and plant size always reduce local growth. Sectoral specialization and diversity have a negative impact on growth, but also increase the growth of a few sectors. Service sectors always exhibit negative specialization effects and positive diversity effects. Competition and plant size have a negative impact and density a positive one, but exceptions are observed for some sectors.     

Decentralized environmental regulations and plant‐level productivity

Using the framework provided by the Porter hypothesis, we study the impact of environmental regulations and enforcement policies on plant‐level green total factor productivity (TFP) growth and its components related to efficiency change and technical change. The detailed microdata we use are from Sweden and for the pulp and paper industry. This industry is the source of significant amounts of water and air pollution and is one of the most heavily environmentally regulated manufacturing industries. Sweden has a unique decentralized regulatory structure where the manufacturing plants have to comply with plant‐specific regulatory standards stipulated at the national level, as well as decentralized local supervision and enforcement. Our empirical results point to beneficial impacts of the environmental policies on plants' green TFP growth and sustainable production practices. We also find that political economy considerations are important, as the presence of the Green Party and aspects like plant size (with corresponding local and regional economic effects) matter in enforcement of the standards.     

An investment planning model for the electricity sector in Nigeria

In this study the methodology of mixed integer programming is used to deal with investment resource allocation problems that involve economies of scale in the Nigerial economic planning environment. The specific application is to long-term investment decisions in the government-operated electric power supply industry (NEPA). The investment planning problem involves determining the optimal generating plant/transmission mix from among a set of fossil fuel and conventional hydro plants which will meet the demand for electricity in Nigeria over the next three decades at minimum cost. Economies of scale in plant construction makes the investment cost function to be non-linear. However the non-linearity is approximated by a fixed charge function. Alternative price assumptions are made about locally found fuel resources (oil, gas, coal and liguite) to calculate the energy cost of fossil fuel plants. Different investment strategies are then evaluated in terms of the present values of the cost of supplying electricity to meet the required demand.     

Large,entrepreneurship and regional development policy: ‘growth poles’ in the Mezzogiorno over 40 years

Large firms are often perceived by economists and policy-makers as ‘growth poles’ to promote development in backward regions. The idea behind the ‘growth poles’ is that large firms may have a leverage effect on the birth and growth of small and medium sized firms. Regional policy in Italy, particularly in the Mezzogiorno, has subsidized large external plants since the 1950s. A new wave of planning agreements in the 1990s is going to redesign and to strengthen this policy orientation. This paper offers empirical data on plant location and growth at provincial level over 40 years. There is no evidence of overall long term growth impact of large acternal plants in the Mezzogiorno, while there are interesting variations by sectors. A theoretical interpretation of the impact of large firms on local entrepreneurial resources is offered, pointing to the negative effects of large firms on the supply of local entrepreneurship. Policy implications are discussed.     

A heuristic algorithm for capacity sensitive requirements planning

Available lot sizing rules for use in MRP (Material Requirements Planning) systems ignore capacity limitations at various work centers when sizing future orders. Planned order releases are instead determined by the tradeoff only between the item's set up and inventory holding costs. This limitation can cause unanticipated overloads and underloads at the various work centers, along with higher inventories, poorer customer service, and excessive overtime.This research explores one way to make MRP systems more sensitive to capacity limitations at the time of each regeneration run. A relatively simple heuristic algorithm is designed for this purpose. The procedure is applied to those planned order releases that standard MRP logic identifies as mature for release. The lot sizes for a small percentage of these items are increased or decreased so as to have the greatest impact in smoothing capacity requirements at the various work centers in the system. This algorithm for better integrating material requirements plans and capacity requirements plans is tested with a large scale simulator in a variety of manufacturing environments. This simulator has subsequently undergone extensive tests, including its successful validation with actual data at a large plant of major corporations.Simulation results show that the algorithm's modest extension to MRP logic significantly helps overall performance, particularly with customer service. For a wide range of test environments, past due orders were reduced by more than 30% when the algorithm was used. Inventory levels and capacity problems also improved. Not surprisingly, the algorithm helps the most (compared to not using it at all as an MRP enhancement) in environments in which short-term bottlenecks are most severe. Large lot sizes and tight shop capacities are characteristic of these environments. The algorithm works the best when forecast errors are not excessive and the master schedule is not too “nervous.”This proposed procedure is but one step toward making MRP more capacity sensitive. The widely heralded concept of “closed-loop” MRP means that inventory analysts must change or “fix up” parts of the computer generated material requirements plan. What has been missing is a tool for identifying the unrealistic parts of the plan. Our algorithm helps formalize this identification process and singles out a few planned order releases each week. This information comes to the analyst's attention as part of the usual action notices. These pointers to capacity problems go well beyond capacity requirements planning (CRP) and would be impossible without computer assistance.Our study produced two other findings. First, short-term bottlenecks occur even when the master production schedule is leveled. The culprits are the lot sizing choices for items at lower levels in the bills of material. “Rough-cut” capacity planning, such as resource requirements planning, therefore is not a sufficient tool for leveling capacity requirements. It must be supplemented by a way to smooth bottlenecks otherwise caused by shop orders for intermediate items. Second, the disruptive effect of large lot sizes is apparent, both in terms of higher inventories and worse customer service. Large lot sizes not only inflate inventories, but paradoxically hurt customer service because they create more capacity bottlenecks. The only reason why management should prefer large lot sizes is if set-up times are substantial and cannot be efficiently reduced. This finding is very much in step with the current interest in just-in-time (JIT) systems.     

基于新能源的高海拔植物制氧技术研究综述

分析了高海拔地区缺氧的危害,以及富氧空气对于高原(医学高原)移居者的重要意义。综述了国内外制氧原理与方法,进行比较,并对高海拔植物制氧的研究方向作了介绍。建设基于植物工厂理论的制氧工厂,用风光互补新能源发电技术为植物制氧提供能源,利用植物的光合作用为移居者提供富氧空气,改善高原缺氧状况,提高脑-体功效。     

提高电厂电气二次设备可靠运行的必要性及途径

本文主要阐述电厂电气二次设备的重要性,且电气二次设备是非常复杂的。很多环节会出现一些问题,导致其运行不可靠。针对这些出现的问题提出自己对解决这些问题和提高电器二次设备安全可靠性的几点看法。从电厂初期设计到施工、到工程的验收、到投运后对设备维护管理及维护人员的技术水平和工作态度等各个环节说明提高设备运行可靠性的具体方法。     

基于绿色增长的我国各地区工业企业技术创新效率研究

本文基于绿色增长对技术创新的方向进行约束,将资源生产率和环境负荷视作产出,运用四阶段DEA模型对我国2009年各省份工业企业技术创新效率进行实证研究。结果表明:环境因素有利于各省份工业企业技术创新效率的提高;剔除环境因素影响后全国平均技术创新效率有所提高,纯技术创新效率上升,而规模效率下降;东部地区的平均纯技术创新效率最高,而中西部地区平均纯技术创新效率偏低,并且低于平均规模效率;经济越发达的省份越容易出现规模报酬递减现象,而经济欠发达的省份则呈现规模报酬递增现象。     

Multiplant MRP

Many manufacturing firms have multiple manufacturing plants, located in geographically diverse parts of the world. This situation is becoming more common, as firms establish new plants in foreign countries to take advantage of low labor cost. In such cases, it is not unusual for the firm to retain production capability of certain key parts in a backup plant, with the necessary equipment and trained workforce in place. High volume production could be obtained relatively quickly from the backup plant in case of an emergency at the main supplying plant. In such multiplant settings, the transportation costs are significant. Throughout this paper, we use the term “multisourced parts” to describe parts produced in more than one location.Material Requirements Planning (MRP) is the component of a total manufacturing control system that is designed to manage inventory and plan orders for parts and material with dependent demand (demand derived from the demand of other items). Most of the literature on MRP systems discusses MRP methodology in a single-plant environment. Most MRP software systems in use today are single-plant systems.Currently, it is common for firms with multiple plants treated as cost centers to use an independent single-plant MRP system for each and handle the transshipment problems manually. Because of lack of coordination of production schedules between supplying and demanding plants, those firms hold more inventory and experience longer lead times than necessary to compensate for uncertainties in schedules and supply policies.The purpose of this article is to enhance single-plant MRP systems for coping with multiplant situations in which: the plants are regarded as cost centers, there exist multisourced parts, and the transportation costs are significant. The multiplant MRP system should recognize that parts are produced in different plants, make offset calculations for in-transit lead times, and consider transportation costs when establishing production requirements and shipping routes for multisourced parts. The objective is, beginning with the corporate-determined master schedule for finished products, to communicate in one planning cycle time-phased planned order release schedules and shipping/delivery schedules to each manufacturing plant producing components for the finished products.We first present a simplified framework for the multiplant MRP system, where a transportation algorithm is incorporated into the MRP logic. Then we refine this simplified framework to handle more complex aspects of a multiplant network. These complexities include the treatment of requirements that are not shipped on time and the regeneration of new MRP schedules. We also observe that the solution to the transportation problem described above is affected by the lot-sizing rules employed. In addition, we discuss several important issues and decisions that confront a firm when implementing a multiplant MRP system.     

中国装备制造业全要素生产率增长的波动与异质性

研究目标：中国装备制造业及其细分行业TFP增长率的测定与分解。研究方法：构建超越对数形式的随机前沿生产函数模型,测算中国装备制造业及其细分行业TFP增长率,并对其进行分解。研究发现：中国装备制造业TFP增长率不但在区域和省份之间存在差异,而且存在明显的内部行业异质性;技术进步和配置效率变化分别是提高和阻碍装备制造业TFP增长率的主要原因和障碍;除技术进步均为正值外,技术效率变化、规模效率变化和配置效率变化在装备制造业各行业中异质性相当明显;装备制造业及其细分行业仍未从真正意义上实现由粗放型向集约型增长方式的转变。研究创新：中国装备制造业细分行业TFP增长率及其异质性。研究价值：为装备制造业转型与升级提供经验证据。     

一起水电机组异常跳闸原因分析和处理

针对智能水电厂设备技术水平不断提升和要求,结合一起水力发电厂运行故障处理实例,警示重视自动化设备的应用和配置获取设备发生故障前后第一时间数据,对运行人员准确判断事故性质缩短异常处理时间,提高电厂的长效机制有着重要作用。     

对多台电机共用一台“软起动器”起动模式的探讨

在一些使用较大功率鼠笼式异步电机的工作场合,当面临起动电源的容量不足以使这些电机直接起动时,用一台"软起动器"来实现多台电机限流起动,运用该方案,既可大幅降低起动电源的设计容量又使起动设备得以简化,不仅可减少设备投资,而且又能实现电机的无冲击软起动,达到双优之功效。     

Backshoring of production activities in European manufacturing

Backshoring – the movement of manufacturing activities from locations abroad back to the home country – has gained some attention in policy discussions and in academic research in recent years. This paper presents empirical evidence on backshoring from a large sample of European manufacturing firms. The data indicate that backshoring is still uncommon among European firms. Around 4% of all firms in our sample have moved production back to the home country between 2013 and mid-2015. The most frequent reasons for backshoring are the loss of flexibility, a lack in quality of the goods produced abroad, and unemployed capacities at home. Flexibility and quality concerns are, in particular, relevant for firms that move production back from Asian countries. Backshoring is most likely for manufacturers of final products and in high-technology sectors, in particular in electrical equipment, information and communications equipment, and the Automotive industry.     

中国装备制造产业创新网络运行效率及提升策略研究

通过分析装备制造产业创新网络运行机理,选取BBC模型、Malmquist指数作为运行效率测度模型,结合装备制造产业创新网络面板数据对其运行效率进行测度,结果表明:2008—2018年中国装备制造产业创新网络整体运行效率以平均每年8.7%的速度递增;从地区角度看,创新网络运行效率呈“东—中—西”阶梯差异态势,但差异态势逐年缩小;从省份角度看,全国26个省份运行效率存在异质性,大体可分为第一、二、三、四梯队;技术水平进步对全要素生产率增长的提升作用要大于纯技术效率和规模效率贡献;技术研发阶段效率低于成果转化阶段效率,两阶段存在脱节现象。创新网络是推动装备制造产业创新升级的重要力量之一,中国要坚定不移地推进创新驱动战略,以提升装备制造产业创新网络运行效率;依据不同地区、不同省份装备制造产业创新网络状况,实施差异化政策组合,以提升运行效率;注重研发技术市场化,以提升成果转化阶段效率。     

Accumulation, Technical Progress, and Increasing Returns in the Economic Growth of East Asia

Adopting homothetic variable returns to scale functional specifications, this study identifies the returns to scale in the aggregate production functions of four East Asian newly industrialized economies–Hong Kong, Korea, Singapore, and Taiwan–and the Group of Five economies based on a maximum likelihood estimation. The study finds evidence of increasing returns in the early developmental stage of the East Asian economies. Separating out the scale contribution from the non-scale factor contributions, the decomposition of the sources of East Asian economic growth differs significantly from the conventional constant returns to scale results, indicating that the role of technical progress is overestimated when constant returns to scale is assumed.