18,645 research outputs found

    Factors influencing employee perceptions in lean transformations

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    The purpose of the study was to investigate employee perceptions during a lean transformation1. The combination of case study and survey methodologies was used to define elements influencing the perceived lean success of shop floor employees. According to our findings, belief, commitment, work method and communication all have a considerable direct impact on workers’ perceptions of lean success. However, their effects are very different based on the scope and focus of changes that is influenced by process characteristics. Perceptions regarding successful lean transformation during a moderate reorganisation of the company’s welding plant, where mainly males work, are affected only by commitment and work method, whereas the deep reorganisation of the sewing plant (populated by female employees) is only influenced by belief and communication

    Technique Design To Increase In-Situ Electrical Connections In A Cubic Anvil Press

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    An experimental technique designed to increase in-situ electrical connections in a cubic anvil press has been developed. Two encompassing cell designs (extruded gasket and pre-formed gasket) were tested with several electrical barrier methods: PVD coatings, G-10/FR-4 and Canvas Electrical (C. E.) phenolic, Teflon and Al ceramic tubing. Many variations of techniques were attempted and each (n)th attempt was founded on the experience from/observation of the results obtained with the (n-1)thtechnique variation. Eighteen pressure cell configurations were designed and tested. The cells with self-extruded gaskets were unsuccessful due to the destructive nature of the extruding gaskets on the wire leads. The final, successful pressure cell was designed with pre-formed gaskets, machined as a single part using a four-axis CNC mill with a C.E. phenolic insert recessed into one cubic cell face which accommodated two lead assemblies connecting to the internal electrodes of the cell. This technique was viable for applied hydraulic load up to 7,000 psi. It allows for HPHT experiments requiring 4-wire measurement methods to be made using only one anvil pair. This technique will also provide increasingly accurate temperature profiling as well as in-situ pressure measurements for large volume pressure cells

    EVALUATION OF SETUP ECONOMIES IN CELLULAR MANUFACTURING

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    This dissertation addresses two research questions relating to the role of setups in discrete parts manufacturing. The first research topic uses a carefully designed simulation study to investigate the role of setup economies in the factory-wide conversion of functional layouts (job shops) to cellular manufacturing. The model-based literature shows a wide dispersion in the relative performance of cellular manufacturing systems as compared to the original job-shop configurations, even when the key performance measure is flow time and the assessment tool used is simulation. Using a standardized framework for comparison, we show how this dispersion can be reduced and consistent results can be obtained as to when the conversion of the job shop is advantageous. The proposed framework standardizes the parameters and operational rules to permit meaningful comparison across different manufacturing environments, while retaining differences in part mix and demand characteristics. We apply this framework to a test bed of six problems extracted from the literature and use the results to assess the effect of two key factors: setup reduction and the overall shop load (demand placed on the available capacity). We also show that the use of transfer batches constitutes an independent improvement lever for reducing flow time across all data sets. Finally, we utilize the same simulation study framework to investigate the benefits of partial transformation, where only a portion of the job shop is converted to cells to work alongside a remainder shop. The second research question examines the role of dispatching rules in the reduction of setups. We use queueing models to investigate the extent of setup reduction analytically. We single out the Alternating Priority (AP) rule since it is designed to minimize the incidence of setups for a two-class system. We investigate the extent of setup reductions by comparing AP with the First-Come-First-Served (FCFS) rule. New results are obtained analytically for the case of zero setup times and extended to the case of non-zero setup time through computational studies

    Chemistry: Space resources for teachers including suggestions for classroom activities and laboratory experiments

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    Curriculum supplement to assist general chemistry teachers in updating instruction materials with aerospace development

    Ariel - Volume 5 Number 1

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    Editors Mark Dembert J.D. Kanofskv Entertainment Editor Robert Breckenridge Gary Kaskey Editor Emeritus David A. Jacoby Photographer Scott Kastner Staff Richard Blutstein Bob Johnson John R. Cohn Joseph Sassani Ken Jaffe Bob Sklarof

    RULE EXTRACTION TO ESTABLISH CRITERIA FOR MINICELL DESIGN IN MASS CUSTOMIZATION MANUFACTURING

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    Minicell-based manufacturing system is used in identifying best minicell designs. The existing method of minicell design generates best minicell designs by designing and scheduling minicells simultaneously. While in this research designing of minicells and scheduling of jobs in minicells is done separately. This research evaluates the effectiveness of hierarchical approach and compares with simultaneous method. Minicell designs with respect to average flow times and machine capacities and both are identified in a multi-stage flow shop environment. Rules for the extraction of good minicell designs in mass customization manufacturing systems are also established
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