131 research outputs found

    Design and Application of Risk Adjusted Cumulative Sum (RACUSUM) for Online Strength Monitoring of Ready Mixed Concrete

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    The Cumulative Sum (CUSUM) procedure is an effective statistical process control tool that can be used to monitor quality of ready mixed concrete (RMC) during its production process. Online quality monitoring refers to monitoring of the concrete quality at the RMC plant during its production process. In this paper, we attempt to design and apply a new CUSUM procedure for RMC industry which takes care of the risks involved and associated with the production of RMC. This new procedure can be termed as Risk Adjusted CUSUM (RACUSUM). The 28 days characteristic cube compressive strengths of the various grades of concrete and detailed information regarding the production process and the risks associated with the production of RMC were collected from the operational RMC plants in and around Ahmedabad and Delhi (India). The risks are quantified using a likelihood based scoring method. Finally a Risk Adjusted CUSUM model is developed by imposing the weighted score of the estimated risks on the conventional CUSUM plot. This model is a more effective and realistic tool for monitoring the strength of RMC.

    Estimating of Capacity of Escalators in London Underground

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    In this paper we discuss a deterministic model for computing the capacity of the escalator in London Underground. We develop this model from fundamental principles of engineering by separating the capacities of standing and walking side of the escalator. By collecting real world data, we find the accuracy of this capacity computation. We also develop a multiple regression model that considers the effect of rise of the escalator with the capacity. We discuss the technical and behavioural reasons for differences in capacities of two methods.

    An Optimization-Based Decision Support System for Strategic Planning in a Process Industry: The Case of an Aluminum Company in India

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    <div align="justify">We describe how a generic multi-period optimization-based decision support system (DSS) can be used for strategic planning in process industries. The DSS is built on five fundamental elements . materials, facilities, activities, storage areas and time periods. It requires little direct knowledge of optimization techniques to be used effectively. Results based on real data from an aluminum company in India demonstrate significant potential for improvement in profits.</div>

    Development of Utility Function for Life Insurance Buyers in the Indian Market

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    <div align="justify">Insurance as a financial instrument has been used for a long time. The dramatic increase in competition within the insurance sector (in terms of providers coupled with awareness for the need for insurance) has concomitantly resulted in more policy options being available in the market. The insurance seller needs to know the buyers preference for an insurance product accurately. Based on such multi-criterion decision-making, we use a logarithmic goal programming method to develop a linear utility model. The model is then used to develop a ready reckoner for policies that will aid investors in comparing them across various attributes</div>

    BISPHENOL A DOSE- AND TIME-DEPENDENTLY INDUCES OXIDATIVE STRESS IN RAT LIVER MITOCHONDRIA EX VIVO

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    Objective: The probable toxic effects of bisphenol A (BPA) on different physiological functions have been reported in animal models. The role of BPA in mitochondrial oxidative stress has not been reported till date. The present study is aimed to elucidate dose- and time-dependent oxidative stress generation by BPA, respectively, in rat liver mitochondria in ex vivo model. Methods: The incubation mixture of BPA-treated groups containing mitochondria, 50 mM potassium phosphate buffer (pH 7.4), and different concentrations of BPA (20–160 μM/ml) (dissolved in 12% DMSO) in a final volume of 1.0 ml was incubated at 37°C in incubator for different time durations (30 min–2 h). Whereas, the incubation mixture of control group contained DMSO (12%), mitochondria and 50 mM potassium phosphatebuffer (pH 7.4).' will be replaced by ‘Whereas, the incubation mixture of control group contained the same constituents except BPA. Result: We have observed significant decrease in mitochondrial intactness incubated with BPA in dose- and time-dependent manner under bright field and confocal microscopic study compared to control. Further, we have observed a decrease in mitochondrial reduced glutathione (GSH) content and increase in lipid peroxidation and protein carbonylation levels in dose- and time-dependent manner in BPA-exposed mitochondria. We have found a significant increase in the activity of Mn-superoxide dismutase and decrease in the activities of GSH peroxidase, GSH reductase, pyruvate dehydrogenase, and other three enzymes of Kreb's cycle dose and time dependently in BPA-exposed mitochondria. The results indicate that exposure to BPA leads to decrease in intactness of mitochondria and increase in oxidative stress in mitochondria isolated from rat liver in a dose- and time-dependent manner. Conclusion: It can be concluded that the incubation of mitochondria isolated from rat liver with BPA, caused oxidative stress-mediated damages in mitochondria in both dose- and time-dependent manners

    Mathematical Modeling for Demurrage Reduction in Coal Transportation for an Indian Thermal Power Plant

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    Competitive pressures on power plants have seen them attempting to reduce their operating expenses for profitable operations. In India, the plants use wagons of the Indian Railways to transport coal from the mines (in case of domestic coal) or from the ports (in case of imported coal). Once these loaded railway wagons have reached the power plant, they need to be unloaded and released within a stipulated time frame. If there is any delay beyond the stipulated time, the power plant has to pay penalty cost to the Indian Railways. In this paper, we describe an analysis of the underlying causes behind these delays. We use correlation analysis, queuing theory and simulation to mathematically model the coal arrival process in the company. The recommendation suggested by the study is currently under implementation.

    Database Structure for a Class of Multi-Period Mathematical Programming Models

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    We describe how a generic multi-period optimization-based decision support system can be used for strategic and operational planning in a company whose processes can be described in terms of five fundamental elements: Materials, Facilities, Activities, Times and Storage-Areas. We discuss the issues of interface design, data reporting and updating, and production and profit planning. We also compare the performances of two different types of database structures with respect to optimization

    An Expanded Database Structure for a Multi-Period, Optimization Model

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    We describe a generic database structure of a multi-period two-stage stochastic optimization based decision support system. The model is an extension of earlier work (Dutta & Fourer; 2004). The model could be used with no or little knowledge of OR/MS. The model maximizes expected contribution subject to material balance, facility capacity, facility input, facility output, storage inventory balance, storage area constraints. The model also considers non-anticipativity constraints for first stage decision variables
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