Risk analysis for operation of aluminum heat exchangers contaminated by mercury

Brazed aluminum plate-fin heat exchangers are extensively used in gas separation processes including LNG, LPG, NGL, nitrogen rejection and olefins manufacture. In situations where mercury is a trace component of feed gas or liquid feeds to crackers, condensation of liquid or precipitation of solid mercury can occur in heat exchanger passes, even with functional mercury removal systems in place. Mercury in liquid phase causes, under certain well-defined conditions, liquid metal embrittlement of susceptible metallurgy or amalgam corrosion of core fins, both of which can lead to sudden loss of pressure containment. Mercury-contaminated aluminum heat exchangers require close scrutiny and quantitative risk assessment to allow safe operation, remediation or to justify replacement. The risk analysis procedure involves computational prediction of mercury deposition, inspection of critical areas, detailed assessment of metallurgy and fabrication, strain analysis of temperature changes during trips and shutdowns and oxide fatigue analysis. Assigning probability of equipment failure requires a complete understanding of the mechanisms of liquid metal embrittlement and amalgam corrosion that operate on aluminum plate-fin heat exchangers. Statistical correlations to known failures are essential to assignment of probability-based risk factors. Probabilities of leak and rupture failure modes can be estimated using amounts and locations of mercury deposits determined from focused inspection or calculated thermodynamically. © 2009 American Institute of Chemical Engineers Process Saf Prog, 2009     

Market power and unemployment

This paper explores the under-consumptionist idea that market power can preclude the existence of a full employment equilibrium within the framework of the modern theory of economic growth. It is shown that the introduction of market power can indeed eliminate the full employment equilibrium. In an attempt to assess the importance of this possibility maximum values for the market power parameters consistent with a full employment equilibrium existing are computed. In some plausible cases these maxima are uncomfortably low suggesting that market power has significant potential for causing unemployment.     

Market power and banking failures

We investigate whether more competition in the banking industry necessarily results in a higher probability of banking failures, as it is often suggested. In our model borrowers face a moral hazard problem, which induces banks to choose between costly monitoring and credit rationing. We show that investment decreases with the lending rate and increases with monitoring effort. Since incentives to monitor are enhanced by market power, the relationship between market structure and investment is ambiguous. In the presence of non-diversifiable risk and decreasing returns to scale, more investment implies higher failure rates. As a result, the relationship between market power and banking failures is ambiguous.     

电力市场中无功电压运行考核方法

分析了无功电力在电网,电厂与用户之间的关系是相互依存和相互支持的,它不同于有功电力市场中的供求、买卖关系。因此,在电力市场中无功电力不能竞价上网,在无功电力交换中不能以能量法则确定无功电能的电价。根据上述客观规律和我国无功电压管理的现状,按电力系统安全、稳定运行与市场化运行的相互协调原则,探讨了在有功电力市场中无功电压的考核办法、必要性和操作规则。     

基于时间序列分析的火电机组运行优化研究

为了预测火电机组在变工况状态下的运行最优值,提高燃煤电厂的燃煤效率,依据燃煤火电厂3个月的各项数据,通过分析并挖掘燃煤火电厂与供电煤率密切相关的可调控参数(主蒸汽温度、主蒸汽压力)随时间的变化关系,利用Holt-Winters时间序列法进行预测。经过计算发现,通过Holt-Winters方法得到的主蒸汽温度和主蒸汽压力的相对误差值分别为0.28%和2.13%。实验结果表明:Holt-Winters时间序列法对预测燃煤火电厂火电机组在变工况下的运行数据是合理的,且其误差小,对燃煤火电厂提高火电机组的燃煤效率具有一定的指导意义。     

New opportunities for the mainland and Taiwan textile businesses

The Chinese mainland and Taiwan started direct air and sea transport and postal services on Dec. 15,2008 amid warming ties, ending a 59-year ban on such links. The launch of direct links has been widely seen as creating new opportunities for greater efficiency and competitiveness for the mainland and Taiwan textile businesses.     

Innovativeness among small businesses: Theory and propositions for future research

Small businesses represent the lifeblood of the economy. Variations in the innovativeness of these firms may help explain why some succeed, but many fail [Frambach, R. T. (1993). An integrated model of organizational adoption and diffusion of innovations. European Journal of Marketing, 25(5), 22-41; Nord, W. R. & Tucker, S. (1987). Implementing routine and radical innovations. Lexington, MA: Lexington Books.]. To understand how small businesses develop and use innovations, a series of depth interviews were conducted with small, family-owned firms in the US and Spain. Results suggest several factors affect innovativeness, including industry-specific, firm-specific, and innovation-specific factors. The study ends with a series of propositions, potential managerial implications of the study, and suggestions for further research.     

Market choice,entry regulation,and joint production: Market access and market service in motor carrier markets

In this paper I develop and estimate a model explaining firm decisions to serve markets. Firms choose to serve multiple markets within a set of markets, but serve only one set of markets at a time. Entry regulation restricts access to markets and may result in firms not serving particular markets or sets of markets. The empirical analysis suggests that Interstate Commerce Commission entry regulation, despite partial deregulation in 1980, continues to affect firm decisions to serve markets and that the effects vary across markets and may cause a firm to serve an entirely different set of markets.     

Organizing for solutions: How project-based firms integrate project and service businesses

Project-based firms (PBFs) increasingly provide comprehensive solutions that consist of products, product systems and services. In solution businesses, long-term collaborative relationships between solution providers and customers are essential. However, little is still known about how relationship marketing activities should be integrated across organizational units, particularly at the practical level of delivering individual projects and services belonging to complete solutions. In this study, based on a case study of a project-based firm and four of its system delivery projects, we identify eight micro-level integration mechanisms for integrating the activities of the project and service business units at the level of delivering a single solution. The joint participation of both project and service business units in project and service activities over the life cycle of a single delivered system enhances the management of customer relationships between the units, and ensures the continuity of the customer relationship over the system life cycle. The identified integration mechanisms also help PBFs to integrate services into their core business and overcome the problems arising from the discontinuous nature of project business.