Application of the DIERS methodology to the study of runaway polymerization: Validation of the DIERS methodology using blow-down tests

The Design Institute for Emergency Relief Systems (DIERS) and more recently the DIERS Users Group have been investigating various aspects of emergency relief for more than 12 years. The DIERS programs have given rise to an in-depth understanding of the basic mechanism of how runaway thermal reactions are safely vented. In concert with the development of the understanding of the venting mechanism, DIERS also developed experimental procedures and computational techniques for estimating emergency vent sizes.     

The reactive system screening tool (RSST): An easy,inexpensive approach to the DIERS procedure

The RSST DIERS vent sizing methodology is revised to provide realistic design equations for reactive systems consistent with available large-scale experience. Using easy to obtain RSST data such as rate of temperature rise and rate of pressure rise excellent agreement is illustrated for hybrid, vapor and gassy reactive systems.     

Batch runaway reaction relief: Re-evaluation of “Credible” scenario

Many chemical reactions in the fine chemical and related industries are performed in a semi-batch manner under isothermal conditions. Relief system design evaluation for runaway reactions, using DIERS methodology for example, is frequently studied adiabatically using data derived from batch mode testing. In many cases, however, evaluation of the process isothermally under the realistic semi-batch mode can be extremely useful, often helping to greatly reduce the vent size as a result of a better understanding of the process. In some cases, it is even possible to eliminate runaway reaction as a viable case for relief sizing. Such evaluations of venting are fully consistent with DIERS methodology. This paper presents the arguments for sizing vents for scenarios other than the very worst case, by objective evaluation of trips and interlocks, so that the level of risk is reduced to an acceptable level without the need for extremely large vents.     

Analysis of diers venting tests: Validation of a tool for sizing emergency relief systems for runaway chemical reactions

A one-dimensional computer model of multiphase, chemically reacting flow has been used to analyze a number of DIERS Phase III venting tests.     

The DIERS users group: A forum for development/dissemination of emergency relief system design technology

DIERS was formed in 1976 to develop methods for the design of emergency relief systems capable of handling runaway reactions [1, 2]. Of particular interest at the time were when tow-phase flow venting would occur and the applicability of different methods for sizing emergency relief systems for two-phase, vapor-liquid flashing flow. Approximately $1.6MM was devoted to investigations of two-phase, vapor-liquid onset/disengagement dynamics and the hydrodynamics of emergency relief systems.     

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.     

Process safety evaluation applying DIERS methodology to existing plant operations

The DIERS methodology can be used to quickly assess the relief capacity envelope for a collection of existing process vessels accounting for both vapor and gassy systems. Easy-to-use vent sizing nomograms and PRESS sheets are proposed that can be completed by the process engineering, the process chemistry and the process safety departments. A vessel volume-vent size diameter relationship is also developed using the source term based on fire exposure to cover a reasonable range of credible upset scenarios. In this way the adequacy of existing relief systems can be quickly surveyed for potential trouble sources—“outliers”—warranting further evaluation and corrective action.     

The use of spreadsheets in modelling accidental releases of toxic chemicals

Many hazardous industrial chemicals are stored as liquidfied compressed gases. To evaluate the possible consequences of a pipeline rupture, hose break, or tank puncture, the safety or process engineer needs a means to estimate the two-phase (liquid and gas) flow rate. Recent technical advances by the American Institute of Chemical Engineers Design Institute of Emergency Relief Systems (DIERS) have produced methods that can be used to compute the two-phase flow rate. These methods are simple and can be completed using a personal computer and a standard spreadsheet program such as Excel (Macintosh) or Lotus (DOS based). This paper presents the two-phase flow rate calculation method and shows how spreadsheets can be used for these calculations.     

Assessing a runaway of a Grignard reaction

The venting and control strategies of a Magnesium Grignard formation reaction were assessed by theoretical predictions of the exotherm and the reaction rate, by simple laboratory measurements of the self heat rate, and by Leung's simplified equations and SAFIRE evaluations, based on DIERS methods. SAFIRE computations showed that the 150 mm dia vent was capable of keeping the reactor pressure below its maximum (MAWP) of 860 kPa for the worst-case exotherm. The response to this evidence was to increase safety protection in the automatic control strategy, following a quantified fault tree analysis of the worst-case runaway scenario.     

Use of DIPPR data in reactive chemical hazard assessment

In the early 1970's AIChE established the concept of Design Institutes. These are cooperative, industrially sponsored research efforts based on getting work done in an area of general interest at low cost to supporters. There are now four active AIChE groups. These are, with date of organization: Design Institute for Physical Property Data (DIPPR), 1978; Research Institute for Food Engineering (RIFE), 1984; Center for Chemical Process Safety (CCPS), 1985; and Center for Waste Reduction Technologies (CWRT), 1989. A fifth, Design Institute for Emergency Relief Systems (DIERS) has completed its work and established a user's group. The subject of this paper, DIPPR, is now in its eleventh year of funded project work. A symposium honoring the completion of DIPPR's tenth year was held in San Francisco in November, 1989. There were 11 papers presented, along with an historical overview. Copies of the 11 papers are available from the Engineering Societies Library in New York City, as Session 40. The papers were published as an AIChE Symposium Series in 1990 [1]. The DIPPR project results that can be used in reactive chemical hazard assessment are highlighted.     

Assessing value-in-use: A conceptual framework and exploratory study

Developing approaches for understanding customer perceived value is a priority for managers and scholars alike. A conceptual framework for assessment of value-in-use is proposed and explored within the context of a maintenance service provider. In contrast to value models in previous empirical research, the framework includes assessment not just of provider attributes but also of the customer's usage processes, as well as customer evaluations of the value-in-use they obtain. Interviews with members of a cross-disciplinary buying group provide support for the framework, including the observations that individuals can assess the quality of their usage processes and that they can articulate value-in-use at both organisational and individual levels; the further concept of network quality also emerges from the data. Assessment of usage process quality as well as service quality evolves as the customer's goals evolve. Practitioners may wish to elicit usage process quality and value-in-use as well as service quality. Research directions include scale development for both usage process quality and value-in-use.     

Strategic decision analysis: Applied decision analysis and its role in the strategic management process

This paper examines a role for applied decision analysis in the strategic management process. It is argued that decision analysis should be regarded both as a heuristic and a ‘thinking’ algorithm for decision structuring and problem diagnosis and, in addition, as an input to the process of policy dialogue. A policy dialogue paradigm using decision analysis is outlined, in which various viewpoints are reconciled by the questioning of analyses and assumptions. This dialogue paradigm is viewed as being compatible with approaches such as strategic assumptions analysis, which have been suggested in the literature as an aid for the processes of problem finding, formulation and solution.     

Towards a differentiated modeling of origin effects in hedonic analysis: An application to auction prices of specialty coffee

Origin matters. This has been shown by numerous studies using either discrete choice or hedonic approaches to derive implicit prices for origin as a product attribute. In most of the hedonic studies, intercept dummies were introduced for specific regional origins and statistically significant coefficients of those variables were seen as an indication of either a superior or inferior reputation, compared to products from other origins. We argue that hedonic pricing models of this type may be too simple to detect the true origin effects if assessments of a product’s sensory quality are available and interact with prior beliefs about reputation. Based on a supply-and-demand framework to explain auction prices, a reduced-form hedonic pricing model is suggested that includes intercept- as well as slope-dummy effects of the regional origin. Because reputation and the objective product quality are particularly important for markets of differentiated, high-quality foods and beverages, we analyze electronic auction markets for specialty coffees. The findings for the Cup of Excellence data reveal that it is important to distinguish reputation, sensory quality, and their interaction as determinants of coffee auction prices, as well as varying origin impacts across market segments.     

创伤骨科病人服装结构解析

创伤骨科病人服装首先应具备良好的功能性、舒适性、卫生性,其次应考虑服装结构便于创伤骨科病人的穿脱。为此本文从服装的开口部位、宽松量、紧固件等方面针对创伤骨科病人进行服装结构探讨,提出了这些部位的设计方法,为创伤骨科病员服结构设计提供理论依据。     

Interest-Rate Volatility, Basis Risk and Heteroscedasticity in Hedging Mortgages

This paper investigates the validity of the OLS regression to estimate the hedge ratio for mortgages (GNMA) and provides alternative methodologies. In particular, this paper is concerned with the variance structure (conditional and unconditional heteroscedasticities) and the misspecification (nonlinearities) of the simple linear regression model for direct as well as cross-hedging. Using data on spot prices of GNMA and futures prices of GNMAs and T-bills for the period September 1979 to January 1985, we show that there exists significant heteroscedasticity particularly for cross-hedging, and nonlinearity between cash and futures prices for direct as well as cross-hedging. Alternative hedge ratio estimates are provided using the Box-Cox transformation model and an autoregressive conditional heteroscedastic (ARCH) Model.     

Sustainable fashion supply chain management under oligopolistic competition and brand differentiation

In this paper, we developed a new model of oligopolistic competition for fashion supply chains in the case of differentiated products with the inclusion of environmental concerns. The model assumes that each fashion firm's product is distinct by brand and the firms compete until an equilibrium is achieved. Each fashion firm seeks to maximize its profits as well as to minimize its emissions throughout its supply chain with the latter criterion being weighted in an individual manner by each firm. The competitive supply chain model is network-based and variational inequality theory is utilized for the formulation of the governing Nash equilibrium as well as for the solution of the case study examples. The numerical examples illustrate both the generality of the modeling framework as well as how the model and computational scheme can be used in practice to explore the effects of changes in the demand functions; in the total cost and total emission functions, as well as in the weights.     

A NOTE ON THE HIERARCHY–TEAM DEBATE

This note explores the debate between proponents of organizational learning who have criticized hierarchy as an obstacle to learning and those who have defended hierarchy as indispensable for large organizations. By considering hierarchy and team as ideal-typical information systems, it is argued that both teams and hierarchies are essential for organizational learning in large organizations. Teams appear to be the key learning units which are indispensable for producing and understanding novel information, and hierarchies are indispensable for processing and storing important learning results. The trade-off between teams and hierarchy can be solved by emphasizing the idea of circularity, involving the ability to switch between teams and hierarchies as complementary information systems in the context of organizational learning.     

Private voluntary standards in the food system: The perspective of major food retailers in OECD countries

The paper examines the main economic and institutional incentives which have driven major OECD food retailers in their use of private voluntary standards and discusses their growing role in shaping the agri-food system. It is based on interviews with quality and safety directors of major OECD retailers and a brief survey of retailers’ actual buyer practices. Though not all retailers are included, these firms account for over 70% of retail food sales in OECD countries. We find that the growing voice of civil society, changing legal and institutional frameworks, increased market concentration and buying power as well as their integration with financial markets has provided the setting for development of private standards. While food safety and quality standards are seen as key to maintaining and improving reputation as well as against legal liabilities, additional standards such as labour, environmental and animal welfare are also gaining ground as strategies for customer loyalty and market shares. The grass-roots retailer move in the harmonization of food safety standards is seen as an initial step towards a global approach to managing the food system, with harmonization of other standards likely in the future. Given their buyer power, these developments can be viewed as a way of governing the food system and will be important for both OECD and non-OECD food and agricultural sector evolution in the coming years.     

Resource-based and institution-based approaches to biotechnology industry development in Malaysia

In this study, we use both resource-based and institution-based theories to examine potential sources of competitive advantage in the relatively new and rapidly growing biotechnology sector. We then use those theories as the basis for a multimethod study to assess the priorities, capabilities, and competitiveness of the emerging biotechnology industry in Malaysia. Multifunctional experts from a biotechnology industry organization in Malaysia identified the use of biotechnology for agriculture and biofuels as key country priorities, with access to funding and talent cited as key capabilities required for successful sector development. The gap between capabilities required and strategic priorities provides a “to do” list for industry development, with government institutions playing a central role in accelerating technology development and providing the capital flows necessary to bridge this gap. Implications include the need for public–private sector collaboration to enable biotech firms to efficiently obtain international investment and alliances to ensure sustainability, as well as to develop bold and creative approaches for developing and recruiting talent both at home and abroad.     

基于 DEA 方法的企业绿色供应链运营效率评价研究

绿色供应链在传统供应链的基础上兼顾了经济与环境效益,是社会可持续发展的重要推动力。对绿色供应链运营效率进行评价有助于企业了解自身的不足,从而对企业绿色供应链管理做出反馈,促进企业绿色供应链运营的良好发展。本文通过文献梳理与总结,构建了企业绿色供应链运营效率评价的投入、产出指标,在此基础上,利用 DEA 方法并通过算例进行实证研究,以期为改善企业绿色供应链运营效率、促进企业更好地实施经济效益与环境效益“双赢”的绿色供应链管理模式提出更加有益的建议。