Analysis of material and capacity requirements with Q-GERT

The purpose of this paper is to report on research conducted to develop a simulation model which incorporates the basic MRP logic into the modelled production process. The objective of the modelling effort is to provide information necessary for planning and controlling of the material and capacity requirements of a production process that includes stochastic processes. The modelling and analysis procedure exploits the fact that the structure of the production process can be logically modelled as a network flow process. The technique employed to facilitate the network modelling is Q-GERT (Graphical Evaluation and Review Technique) modelling and simulation language. A case application is presented to demonstrate a prototype model, followed by a report of the simulation results. The model is designed to provide answers and insights to the following questions: (1) how long must each production centre operate to yield the specified quantities of finished products, (2) what is the expected lead time required to complete the production of finished products, (3) what are the utilization rates for various processing stations, and/or percentage idle times due to lack of preprocess inventories, and (4) where do bottlenecks occur in the production process, as evidenced by large queues of materials or subassemblies prior to the machine centres.     

Some Fundamental Innovations in Direct Solvent Extraction of Low Molecular Weight Biological Products

Abstract

The separation of low molecular weight biologically produced molecules by fermentation processes is a very important area of development in the pharmaceutical industry and elsewhere. The problems of separation processes for economic exploitation are significant. The use of liquid-liquid solvent extraction as a means of recovering such products is chemically very attractive on account of the high degree of selectivity control which is available by adjustment of both the chemical and physical structure of the solvents. The paper reviews some of the problems arising from using solvent extraction especially in relation to mass transfer processes, physical contacting processes, and product and solvent recovery. The technical and scientific issues surrounding rheology and the presence of surfactants and solid material in the extraction of fermentation solutions are discussed in some detail. The influence of such phenomena on droplet behaviour is a particular source of focus in the paper. The use of novel contacting techniques including intensified electrostatic contact for both dispersion and coalescence purposes is described. The application of these techniques to some well known biological product extractions are reviewed briefly including those for ethanol and penicillin G. The potential application of solvent extraction to some of the more recent biological products including arene cisdihydrodiols is reviewed briefly. Some of the implications for equipment application and, design are also reviewed in relation to direct extraction of biological products.     

The Role of Acquisitions in Reshaping Business Capabilities in the International Telecommunications Industry

This paper focuses on the relationships between observed processesof post-acquisition activities within four cross-border horizontalacquisitions that occurred in the telecommunications equipmentmanufacturing sector between 1988 and 1992. We discuss the desirabilityof such acquisitions from a corporate and social welfare standpoint.We report a detailed survey of the context, post-acquisitionactivities and outcomes of the four acquisitions. The acquisitioncontext includes industry characteristics, target characteristics,target strengths and acquisition motives. Post-acquisition activitiesinclude several dimensions of business restructuring, resourceredeployment and creation of integration mechanisms. Acquisitionoutcomes include impact on business capabilities, financialperformance and judgments of overall success. We conclude thatthe results provide stronger support for strategic reconfigurationand productive efficiency explanations for horizontal acquisitionsthan they do for market power, target mismanagement or resourceappropriation explanations.     

MEAT TEXTURE CHARACTERISATION: COMPARISON OF CHEWING PATTERNS, SENSORY AND MECHANICAL MEASURES

The texture of beef, varied by muscle (semimembranosus and semitendinosus), myofibrillar status (ageing time and cold-shortening) and cooking temperature (60C and 80C), was determined by a sensory profile, chewing patterns (determined from surface electromyograms) and mechanical properties of the cooked meats measured at low and high deformation in compression, shear (cutting) and by dynamic (viscoelasticity) tests. The meat factors were discriminated differently by the different measurements showing that they detected differently the various origins of meat texture. Only the maximum modulus before 70% compression and sensory assessments and EMG gave discrimination among all the meat factors. Two main sensory dimensions were found from the profile: juiciness and tenderness with a third related to the determination of elasticity. Juiciness, which varied most between cooking temperatures, was better related to mechanical parameters at low strain rather than high strain and to initial muscular activity rather than later muscular activity. Conversely, tenderness was better related to high strain mechanical properties and to measurements in the middle or later part of the mastication process suggesting that tenderness assessment requires structural disintegration of meat.