Preventing explosions during chemicals and materials storage

Simple passive means are considered for preventing explosions in connection with storage of non-reactive and reactive materials. For high-pressure storage, special attention is given to the elimination of BLEVEs. Cost-effective passive features are proposed to accommodate both global and local fire impingement conditions. For atmospheric pressure storage, passive features are considered to accommodate potential fire exposure and prevent runaway scenarios for reactive systems.     

关注人民币升值，正确看待利与弊

原材料价格上涨、劳动力价格上涨,再加上出口退税率的下调和贷款利率去年的连续上调,使得本来就不具备强大竞争优势的中小企业生存状态十分艰难,使得这些企业更添烦恼。笔者在浙江云和、永嘉等玩具生产基地采访,这里的玩具企业负责人几乎都会感叹同一句话——“大环境不好”。他们说的大环境,当然包括了原材料、劳动力、出口退税、出口准入制度门槛等因素,然而,人民币快速的升值,更是给这些以出口为主的中小玩具企业添了烦恼。云和的一家木制玩具企业负责人这样感叹：“好不容易与外商的签下一份大单,但半年的合同做下来,我就莫名其妙的少了几十万,现在人民币还在升值,我都不敢和外商用美元来交易了”。     

Application of twin screw extruders for reactive processing

Reactive extrusion has grown in a few years from a specialized technique for creating experimental materials to the preferred production technique for manufacture of standard polymer systems (ex. polyurethanes) and modification of these systems (ex. grafting). The complexity of the extruder system design has also grown tremendously. The ability of reactive extrusion to produce a myriad of products in a single piece of capital equipment makes it attractive to R&D, manufacturing and financial groups.     

Workplace Industrial Relations under Different Regulatory Systems: A Survey-Based Comparison of Australia and Britain

The focus of the paper is upon the extent to which different national regulatory systems give rise to different institutions and outcomes at the workplace. It uses data from the Australian Workplace Industrial Relations Survey and the third British Workplace Industrial Relations Survey to examine a number of hypotheses which suggest that the different regulatory systems of these countries have produced distinct patterns of industrial relations at the workplace. It is concluded that, while there is substantial evidence that the countries' different regulatory systems have had distinct effect on industrial relations institutions and outcomes, these are not as straight forward as earlier work has suggested.     

钢包半钢脱磷的工业试验

结合承德钢厂转炉半钢特性,在100t钢包中使用侧吹氧枪和底吹氩气进行工业脱磷试验。试验表明,大供氧流量条件有利于提高炉渣的脱磷能力;脱磷率随半钢温度升高呈上升的趋势;随着脱磷渣碱度上升,脱磷率呈先上升后下降的趋势,脱磷渣碱度为3.26时,脱磷率最高,脱磷率为52.1%。     

Relief system design scope of CCPS effluent handling guidelines

The forthcoming CCPS Guidelines for Effective Handling of Emergency Release Effluents includes the methodology for defining effluent flow rates and characteristics during emergency pressure relief event. The intent is to provide the user with relief systems in a typical process unit without requiring expert assistance or access to other documents. Cases requiring special design training and methodology due to combinations of multi-phase, multi-component, reactive, geometric and thermodynamic complexities are identified and illustrated in the Guidelines. However, the complete design technology for such cases is beyond the scope of these Guidelines; reference is given to applicable documents.     

Common Knowledge Reference Price and Asymmetric Price Adjustments

There is abundant empirical evidence showing that asymmetric price adjustments exist in a wide variety of markets. Prices tend to rise faster when costs rise, relative to the rate at which prices drop when costs fall. This paper argues that a common knowledge reference price—a government suggested retail price—eases the existence of asymmetric price adjustments in a scenario where costs are ever-increasing. Our analysis of the Colombian retail gasoline market suggests that when costs rise by more than the reference price, prices tend to rise more slowly relative to when costs grow by less than the reference price.     

电力滤波器的研究现状概述

谐波对电网和其他系统的危害越来越大。解决谐波问题的一种有效方法就是使用滤波装置,无源滤波器因其功率大、成本低等优势在大功率用电系统中得到了广泛的应用;有源电力滤波器(APF)由于有很好的滤波特性及动态特性好等优势一直得到广泛关注,但其容量又限制了其实际应用。将有源电力滤波器与无源电力滤波器相结合,构成混合有源滤波器(AF),取两者之长补有源电力滤波器之短,可以降低谐波补偿系统的成本,达到APF实用的目的。     

A Note on Equivalent Fixed Rate and Variable Rate Loans; Borrower's Perspective

A common situation is where a borrower is offered the choice of two types of loans—a fixed interest rate loan for a fixed period or a variable interest (floating interest) rate loan. Usual wisdom and advice is that the borrower opts for the fixed rate loan if interest rates are anticipated to rise in the future or opts for the variable rate loan if interest rates are anticipated to fall. However, depending on the magnitude of the rates offered, and the rate uncertainty in the market, such wisdom may not always be well founded. This note demonstrates why this might be. It derives a readily usable, low-mathematical-background expression showing, for borrowers, when fixed and variable rate loans are equivalent and when one rate type is better/worse than the other.     

A consumer-oriented model for analysing the suitability of food classification systems

The main function of food classification systems is to regulate the market and inform it (consumers above all) about the different types of products and their characteristics. However, the reality is that many of these systems give rise to confusion and prevent consumers from obtaining a clear idea of them, making the purchasing process more difficult. The objective of this study was to propose a method that can be used as a basis or reference framework for analysing the suitability of any food classification system, based on maximising consumer comprehension and learning, before introducing it into the market. The model proposed establishes the procedure and the necessary indicators for identifying the advantages and drawbacks of each of the different systems, making it possible to compare their suitability. The model was tested empirically by comparing the current classification of orange juices and Iberian ham with two different proposals, in an experiment conducted with an online consumer panel, and using MANCOVA to analyse the differences between the six indicators related to consumer learning results. It was concluded that the model is suitable for assessing the suitability of the classification systems, as it shows technical viability, ease of introduction in practically any situation and the ability to facilitate and guide the process of drawing up consumer-oriented food classification systems.     

河北红松风电场接入电网稳定性问题浅析

随着大批风电场的建设,风电机组在电网中所占比例越来越高。由于风力发电机组的可控性远弱于火力发电机组和水力发电机组,所以给电网带来了许多新的技术问题,尤其是并网风电机组在持续运行和切换操作过程中产生的电压波动和闪变,会对当地电网的电能质量产生不良影响。结合河北红松风电场实际情况,从并网风电机组输出的功率波动、无功功率补偿、电网稳定性等方面出发,分析了风力发电引起电网电压波动和闪变的主要原因,对降低电网电压失稳进行了浅析。     

Modeling and simulation of order-driven planning policies in build-to-order automobile production

In adopting build-to-order order fulfillment systems, automotive companies strive to better synchronize their production output with market demand. This essentially gives rise to a new paradigm in production planning. Since all business is linked to customer orders, the operational performance is substantially determined by order-driven planning. Therefore, a clear understanding of the associated planning tasks, order promising and master production scheduling, as well as their dynamic interaction is essential. Based on the analysis of the decision situation of order-driven planning in build-to-order settings, we provide a framework comprising separate interlinked quantitative models for order promising and master production scheduling. The focus of the contribution is on the modeling and evaluation of both models in a dynamic setting. The approach is evaluated by means of a simulative analysis using empirical data from the automotive industry. Conclusions regarding the potentials of such systems with respect to customer service, the leveling of resource utilization, and holding are presented.     

注射成型工艺对聚丙烯收缩率的影响

研究了保压时间、注射温度、模具温度、注射压力、注射速度对聚丙烯收缩率的影响。结果表明:保压时间的增加能降低聚丙烯制品的收缩率,聚丙烯制品的收缩率随注射温度的提高而增加,模具温度的提高会加大聚丙烯制品的收缩率,聚丙烯制品的收缩率会随注射压力的提高而减少,注射速度的降低将减少聚丙烯制品的收缩率,注射工艺条件的改变对不同规格聚丙烯制品的收缩率的影响也不同。     

Housing Quality and the Structure Tax: Evidence from Microdata

In a previous study [13] I showed theoretically that housing quality will rise when the structure tax rate falls if capital is a noninferior input. This result was supported empirically with aggregate SMSA-level data. The present study reports empirical confirmation with microdata more appropriate for the theoretical hypothesis.     

浅析石油企业一体化管理体系

石油企业近年来相继引入并实施了ISO9000、ISO14000、OHSAS18000、HSE管理体系,多个管理体系独立实施造成了大量文件和资源的重复使用,增加了管理人员、操作成本和体系维护费用,也给基层岗位员工增加了工作量。探索和实施一体化管理体系,开展多体系整合工作,逐步实现机构一体化、人员一体化、管理一体化的管理模式是现代企业管理的趋势。就石油企业如何推行一体化管理体系,从现状和问题、必要性和可行性分析、一体化管理体系要素融合原则、一体化管理体系文件层次结构等方面,对一体化管理体系的建立进行了探索。     

Design of quench system for runaway reactions using bench-scale equipment

Runaway chemical reactions are a potential problem in many sectors of the chemical industry. The typical hazard scenario involves a batch (or semi-batch) chemical reaction where, due to an operator error or instrument failure, the reaction temperature begins to accelerate rapidly. The rise in temperature is, of course, accompanied by a rise in pressure and in order to prevent vessel rupture, some means of protection must be provided. The common approach to overpressure protection in the industry is to fit a relief device to the reactor vessel in question; the device opens at a predetermined pressure and, provided it is sized correctly, the maximum pressure can be kept within acceptable limits. The Design Institute for Emergency Relief Systems (DIERS), organized through the auspices of the AIChE [1], undertook several years of research to develop the methodology for the sizing of relief systems to cope with runaway reactions. The emphasis in industry has changed so considerably since the DIERS work that companies are interested in avoiding the release of chemicals to the environment in addition to preventing equipment damage. This adds considerable complexity to the relief system and must be evaluated with the same thoroughness as the vent design.     

The Borrower's Perceived Risk in Mortgage Choice

We investigate how borrowers perceive the risk in the adjustable rate mortgage (ARM) versus fixed rate mortgage (FRM) choice. We develop a mortgage choice model where the coefficient on the long‐term bond risk premium is conditional on the borrower's perceived risk. We show that the perceived risk fluctuates over time according to the short‐term interest rate level and housing market conditions. We find that when the short‐term rate level is high (low), the borrowers perceive low (high) risk of a short‐term rate rise, thus opting for ARMs (FRMs). Also, during a down housing market they become more risk‐averse perceiving higher risk in choosing ARMs. The perceived risk level alters the borrowers’ sensitivity to the long‐term bond risk premium.     

时滞超混沌系统的同步

时滞混沌系统是无穷维系统 ,由这样的系统产生的超混沌可具有多个正的L yapunov指数 ,因此系统可以产生复杂的时间序列。这个特征使它特别适用于保密通讯。本文正是根据时滞超混沌系统的这一特点 ,给出了一种同步时滞混沌系统的新方法。通过L yapunov稳定理论得到了系统同步时系统参数满足的条件。数值仿真表明了该方法的有效性。     

From Experience: Linking Projects to Strategy

There is a dramatic rise in the use of project management as organizations shift to provide customer-driven results and systems solutions. Some implementations of project management have been successful, whereas others are spectacular failures. A common occurrence in many organizations is too many projects being attempted by too few people with no apparent link to strategy or organizational goals. Research and experience indicate that the support of upper management is critical to project success. This article reviews actions that upper managers can take to create an environment for more successful projects in their organizations. Specifically, the authors discuss practices for upper manager teamwork and offer a complete model for selecting projects that support a strategic emphasis. The article includes experiences from within Hewlett-Packard Company. © 1999 Elsevier Science Inc.     

Problems of modern agriculture

Conventional high-input agriculture gives rise to biological problems related to the breakdown of the selfsustaining recycling characteristic, normal to living systems, by reducing saprophytes, humus return and nitrogen fixing organisms. Thus, the system becomes increasingly dependent on greater inputs. In addition, reduced diversification often leads to an increase in plant and animal diseases, and pest and weed problems. These are countered by increased applications of manufactured inputs which may cause agro-industry pollution and further breakdown of the system. An alternative which may reduce or eliminate some of these problems is ecological agriculture.