244,679 research outputs found

    Analysis of Shop Floor Performance through Discrete Event Simulation: A Case Study

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    Shop floor performance management is a method to ensure the effective utilization of people, processes, and equipment. Changes in the shop floor might have a positive or negative effect on production performance. Therefore, optimal shop floor operation is required to enhance shop floor performance and to ensure the long-term efficiency of the production process. This work presents a case study of a semiconductor industry. The punching department is modeled to investigate the effect of changes in the shop floor on production performance through discrete event simulation. The effects on the throughput rate, machine utilization, and labor utilization are studied by adjusting the volume of parts, number of operators, and flow pattern of parts in a series of models. Simulation results are tested and analyzed by using analysis of variance (ANOVA).The best model under changes in the shop floor is identified during the exploration of alternative scenarios

    The Study Of Production Regimes And Quality Parameters Of Extruded Feed Additive Based On Corn Seed And Substandard Egg Mass

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    On the base of practical studies were established the rational parameters of technological processes of production of extruded feed additive. There was determined an expedience of mixture of substandard chicken egg mass and the crushed corn seed in two stages in frame (during 18 s) and blade (during 120…180 s) mixers. There were determined the optimal regimes of mixture extruding: pressure in working zone of extruder 2…3 mPa, consumed force of electric motor 4,0…4,5 kW, temperature on outcome of extruder 110…120 ºС, duration of process 60…120 s, diameter of matrix port 10 mm.There were given the results of study of parameters of quality and nutritive value of extruded feed additive. It was established, that in the process of extruding the quality parameters of food additive are improved at the expense of dextrinization and gelatinization of starch, decrease of bacterial and fungal pollution, disinfection of product.There was proved a possibility to solve problem of utilization of defective eggs at feeding poultry

    BUSINESS PROCESS FRAMEWORK AND IT ARCHITECTURE FOR SMART METER READING

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    The implementation of smart metering has an impact on the energy business processes and the corresponding enterprise IT architecture. The utilization level of the new meter assets and system support sets the amount of new services and internal efficiency that can be provide by the investment. Optimizations in terms of streamlined business processes, reduced costs, increased profit, lower end-user prices and by considering environmental aspects, less energy losses and optimal energy production can be reached by the entire energy process starting with generation, grid and transmission processes, distribution and energy consumption. Business drivers for the implementation are beside law, government, regulator and sometimes the energy companies themselves in particular business informatics and the IT services

    Low carbon manufacturing: Characterization, theoretical models and implementation

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    Today, the rising of carbon dioxide (CO2) emissions is becoming the crucial factor for global warming especially in industrial sectors. Therefore, the research to reduce carbon intensity and enhance resources utilization in manufacturing industry is starting to be a timely topic. Low carbon manufacturing (LCM) can be referred to the manufacturing process that produces low carbon emissions intensity and uses energy and resources efficiently and effectively during the process as well. In this paper, the concepts of LCM are discussed and the LCM associated theoretical models, characterization and implementation perspective explored. The paper is structured in four parts. Firstly, the conception of low carbon manufacturing is critically reviewed then the characterization of low carbon manufacturing is discussed and formulated. Third part, the theoretical models are developed with initial models by using the theory from supply chain modeling and linear programming solutions (LP). The models show the relationship of resource utilizations and related variables for LCM in two levels: shop-floor and extended supply chain. Finally, the pilot implementations of LCM are discussed with two approaches: desktop or micro machines and devolved manufacturing. The paper is concluded with further discussions on the potential and application of LCM for manufacturing industry

    Time-to-build obsolescence and the technological paradox

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    The paper focusses on the technological paradox. To analyze the possible temporary negative eect of an innovation, we make use of a ow representation of production. Our aim is to show that such phenomenon can be justied by a simple property of the production process: in real time costs strictly come before proceeds.Moving in the same direction of Amendola (1974), we analyze the obsolescence effect induced by a rise in the interest rate. Furthermore, we analyze the role of capital market stickiness on the timing of the technological paradox and on the distribution of the obsolescence eect among the different stages of a vertical integrated production system.Technological paradox, technology adoption, time-to-build, obsolescence.

    Capital utilization: maintenance costs and the business cycle

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    In this paper we analyze the role played by capacity utilization and maintenance costs in the propagation of aggregate fluctuations. To this purpose we use an extension of the general equilibrium stochastic growth model that incorporates a depreciation technology depending both upon capital utilization (depreciation in use assumption) and maintenance costs. In addition, we argue that the maintenance activity must be countercyclical, because it is cheaper for the firm to repair and maintain machines when they are stopped than when machines are being employed. We show that the propagation mechanism associated to our technology assumption is quantitatively important: the countercyclicality of maintenance costs contributes significantly to magnify and propagate aggregate fluctuations

    Taxonomic classification of planning decisions in health care: a review of the state of the art in OR/MS

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    We provide a structured overview of the typical decisions to be made in resource capacity planning and control in health care, and a review of relevant OR/MS articles for each planning decision. The contribution of this paper is twofold. First, to position the planning decisions, a taxonomy is presented. This taxonomy provides health care managers and OR/MS researchers with a method to identify, break down and classify planning and control decisions. Second, following the taxonomy, for six health care services, we provide an exhaustive specification of planning and control decisions in resource capacity planning and control. For each planning and control decision, we structurally review the key OR/MS articles and the OR/MS methods and techniques that are applied in the literature to support decision making

    Molecular crowding defines a common origin for the Warburg effect in proliferating cells and the lactate threshold in muscle physiology

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    Aerobic glycolysis is a seemingly wasteful mode of ATP production that is seen both in rapidly proliferating mammalian cells and highly active contracting muscles, but whether there is a common origin for its presence in these widely different systems is unknown. To study this issue, here we develop a model of human central metabolism that incorporates a solvent capacity constraint of metabolic enzymes and mitochondria, accounting for their occupied volume densities, while assuming glucose and/or fatty acid utilization. The model demonstrates that activation of aerobic glycolysis is favored above a threshold metabolic rate in both rapidly proliferating cells and heavily contracting muscles, because it provides higher ATP yield per volume density than mitochondrial oxidative phosphorylation. In the case of muscle physiology, the model also predicts that before the lactate switch, fatty acid oxidation increases, reaches a maximum, and then decreases to zero with concomitant increase in glucose utilization, in agreement with the empirical evidence. These results are further corroborated by a larger scale model, including biosynthesis of major cell biomass components. The larger scale model also predicts that in proliferating cells the lactate switch is accompanied by activation of glutaminolysis, another distinctive feature of the Warburg effect. In conclusion, intracellular molecular crowding is a fundamental constraint for cell metabolism in both rapidly proliferating- and non-proliferating cells with high metabolic demand. Addition of this constraint to metabolic flux balance models can explain several observations of mammalian cell metabolism under steady state conditions
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