374,796 research outputs found

    Electricity from photovoltaic solar cells: Flat-Plate Solar Array Project final report. Volume VI: Engineering sciences and reliability

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    The Flat-Plate Solar Array (FSA) Project, funded by the U.S. Government and managed by the Jet Propulsion Laboratory, was formed in 1975 to develop the module/array technology needed to attain widespread terrestrial use of photovoltaics by 1985. To accomplish this, the FSA Project established and managed an Industry, University, and Federal Government Team to perform the needed research and development. This volume of the series of final reports documenting the FSA Project deals with the Project's activities directed at developing the engineering technology base required to achieve modules that meet the functional, safety and reliability requirements of large-scale terrestrial photovoltaic systems applications. These activities included: (1) development of functional, safety, and reliability requirements for such applications; (2) development of the engineering analytical approaches, test techniques, and design solutions required to meet the requirements; (3) synthesis and procurement of candidate designs for test and evaluation; and (4) performance of extensive testing, evaluation, and failure analysis to define design shortfalls and, thus, areas requiring additional research and development. During the life of the FSA Project, these activities were known by and included a variety of evolving organizational titles: Design and Test, Large-Scale Procurements, Engineering, Engineering Sciences, Operations, Module Performance and Failure Analysis, and at the end of the Project, Reliability and Engineering Sciences. This volume provides both a summary of the approach and technical outcome of these activities and provides a complete Bibliography (Appendix A) of the published documentation covering the detailed accomplishments and technologies developed

    The Evolution of Shopping Center Research: A Review and Analysis

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    Retail research has evolved over the past sixty years. Christaller\u27s early work on central place theory, with its simplistic combination of range and threshold has been advanced to include complex consumer shopping patterns and retailer behavior in agglomerated retail centers. Hotelling\u27s seminal research on competition in a spatial duopoly has been realized in the form of comparison shopping in regional shopping centers. The research that has followed Christaller and Hoteling has been as wide as it has been deep, including literature in geography, economics, finance, marketing, and real estate. In combination, the many extensions of central place theory and retail agglomeration economics have clearly enhanced the understanding of both retailer and consumer behavior. In addition to these two broad areas of shopping center research, two more narrowly focused areas of research have emerged. The most recent focus in the literature has been on the positive effects large anchor tenants have on smaller non-anchor tenant sales. These positive effects are referred to as retail demand externalities. Exploring the theoretical basis for the valuation of shopping centers has been another area of interest to researchers. The primary focus of this literature is based in the valuation of current and expected lease contracts

    Turbulent liquid–liquid dispersion in SMV static mixer at high dispersed phase concentration

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    The aim of this paper is to investigate the influence of physico-chemical parameters on liquid–liquid dispersion at high dispersed phase concentration in Sulzer SMV™ mixer. Four different oil-in-water systems involving two different surfactants are used in order to evaluate the effect of interfacial tension, densities and viscosities ratio on mean droplets size diameters. Moreover the influence of the dispersed phase concentration on the pressure drop as well as on the droplet size distribution is investigated. Two different droplets size distribution analysis techniques are used in order to compare the resulting Sauter mean diameters. The comparison between residence time in the mixer and surfactants adsorption kinetics leads to take into account the evolution of the interfacial tension between both phases at short times. Finally experimental results are correlated as a function of dimensionless Reynolds and Weber numbers

    Engineering Feasibility Study of Fire Island as a Location for a Future Correctional Facility: Final Report

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    The "Legal Factors" section appearing on page 38–50 of this report was prepared by Stephen Conn of the UAA Justice Center, School of Justice. / This report is part of the Fire Island Prison Feasibility Study, a project conducted jointly by the School of Justice and School of Engineering at University of Alaska, Anchorage under contract to the Alaska Department of Corrections. The project undertook to assess the feasibility of locating a correctional facility on a 4,240 acre tract of land on Fire Island, which lies in Upper Cook Inlet about three miles off Point Campbell within the Municipality of Anchorage. The project was divided into three major phases: (1) an assessment of future bed space needs of the Alaska Department of Corrections; (2) an evaluation of the physical site and cost estimates for prison construction and operation; and (3) a public opinion survey and open discussion.This report provides the final results of an engineering assessment and evaluation of a 4,240 acre tract of land on Fire Island for a proposed correctional facility. Fire Island is an island in Upper Cook Inlet about three miles off Point Campbell within the Municipality of Anchorage. The report describes climatic and geophysical factors on the island including temperature, precipitation, wind, topography, geology and soils, seismicity, slide potential, and coastal erosion; facility site evaluation including suitability of soils for building foundations, transportation and site access, utility availability (water, wastewater and solid waste disposal, electricity, and communications), and legal factors (constitutional issues, prison security, and access to prisons); and estimated construction costs. Comparisons with alternative prison sites at Palmer and Goose Bay, both located within the Matanuska-Susitna Borough, are provided. A bibliography of land and facility studies of Fire Island is included.Alaska Department of Corrections1. Executive Summary / 2. Introduction / 3 . Location of the Fire Island Site / 4. Engineering Feasibility of Fire Island as a Potential Prison Site / 5. Estimated Construction Costs for Correctional Facilities / 6. Benefits and Liabilities of Alternative Sites / 7. Summary and Conclusions / References / Bibliography of Fire Island Land and Facilities Studie

    A Fundamental Study of Refrigerant Line Transients

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    Managing the trade-off implications of global supply

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    The cost versus response trade-off is a growing logistics issue due to many markets being increasingly characterized by demand uncertainty and shorter product life cycles. This is exacerbated further with supply increasingly moving to low cost global sources. However, the poor response implications of global supply are often not addressed or even acknowledged when undertaking such decisions. Consequently, various practical approaches to minimising, postponing or otherwise managing the impact of the demand uncertainty are often only adopted retrospectively. Even though such generic solutions are documented through case examples we lack effective tools and concepts to support the proactive identification and resolution of such trade-offs. This paper reports on case-based theory building research, involving three cases from the UK and USA used in developing a conceptual model with associated tools, in support of such a process

    Optimal operations and resilient investments in steam networks

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    Steam is a key energy vector for industrial sites, most commonly used for process heating and cooling, cogeneration of heat and mechanical power as a motive fluid or for stripping. Steam networks are used to carry steam from producers to consumers and between pressure levels through letdowns and steam turbines. The steam producers (boilers, heat and power cogeneration units, heat exchangers, chemical reactors) should be sized to supply the consumers at nominal operating conditions as well as peak demand. First, this paper proposes an Mixed Integer Linear Programing formulation to optimize the operations of steam networks in normal operating conditions and exceptional demand (when operating reserves fall to zero), through the introduction of load shedding. Optimization of investments based on operational and investment costs are included in the formulation. Though rare, boiler failures can have a heavy impact on steam network operations and costs, leading to undercapacity and unit shutdowns. A method is therefore proposed to simulate steam network operations when facing boiler failures. Key performance indicators are introduced to quantify the network’s resilience. The proposed methods are applied and demonstrated in an industrial case study using industrial data. The results indicate the importance of oversizing key steam producing equipments and the value of industrial symbiosis to increase industrial site resilience

    Managers Handbook for Software Development

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    Methods and aids for the management of software development projects are presented. The recommendations are based on analyses and experiences with flight dynamics software development. The management aspects of organizing the project, producing a development plan, estimation costs, scheduling, staffing, preparing deliverable documents, using management tools, monitoring the project, conducting reviews, auditing, testing, and certifying are described

    Land Transfers: Process and Processors

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