818 research outputs found

    Summary of electric vehicle dc motor-controller tests

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    The differences in the performance of dc motors are evaluated when operating with chopper type controllers, and when operating on direct current. The interactions between the motor and the controller which cause these differences are investigated. Motor-controlled tests provided some of the data the quantified motor efficiency variations for both ripple free and chopper modes of operation

    Baseline tests of the AM General DJ-5E electruck electric delivery van

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    An electric quarter ton truck designed for use as a postal delivery vehicle was tested to characterize the state of the art of electric vehicles. Vehicle performance test results are presented. It is powered by a single-module, 54 volt industrial battery through a silicon controlled rectifier continuously adjustable controller with regenerative braking applied to a direct current compound wound motor

    Baseline tests of the EVA contractor electric passenger vehicle

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    The EVA Contactor four door sedan, an electric passenger vehicle, was tested to characterize the state-of-the-art of electric vehicles. It is a four passenger sedan that was converted to an electric vehicle. It is powered by 16 series connected 6 volt electric vehicle batteries through a four step contactor controller actuated by a foot accelerator pedal. The controller changes the voltage applied to the separately excited DC motor. The braking system is a vacuum assisted hydraulic braking system. Regenerative braking was also provided

    Solomon Islands languages : an internal classification

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    Installation and initial operation of a 4100 watt wind turbine

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    The results are presented of 211 days of operation of the 4.1 kilowatt wind turbine, which was the largest commercially available wind turbine. The wind turbine, electric controls and load bank, and the pivoted tower are described

    Developing an Academic Library Assessment Plan: A Case Study

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    Purpose – The purpose of this paper is to analyze the process of developing an academic library assessment plan and its relation to the furtherance of a culture of assessment. Design/methodology/approach – Qualitative study of a university library’s assessment planning process; findings based on documentary evidence as well as an employee survey; analysis framed in relationship to relevant literature. Findings – Planning for the future of assessment offered the Jerry Falwell Library a significant opportunity for organizational change. Evaluations of the planning process were mixed, but generally revealed evidence of conditions associated with the development of a culture of assessment. Participants saw planning as the product of both external and internal factors. The plan’s orientation toward value and impact, though clearly understood, was not universally appreciated. Implementation of the plan remains a substantial challenge. Research limitations/implications – Reliability is subject to the limitations inherent to qualitative methods. Single case study design limits generalizability to different contexts. Practical implications – The goal of developing a culture of assessment is not to be achieved easily or quickly. Library employees may be most inclined to support an assessment agenda when it is driven by internal factors such as quality improvement and the pursuit of efficiency and effectiveness. Originality/value – The study emphasizes the process of developing an assessment plan at a university with a strong teaching mission. Additionally, it provides insight into the relationship between assessment planning and a culture of assessment

    Multi-layered Ruthenium-modified Bond Coats for Thermal Barrier Coatings

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    Diffusional approaches for fabrication of multi-layered Ru-modified bond coats for thermal barrier coatings have been developed via low activity chemical vapor deposition and high activity pack aluminization. Both processes yield bond coats comprising two distinct B2 layers, based on NiAl and RuAl, however, the position of these layers relative to the bond coat surface is reversed when switching processes. The structural evolution of each coating at various stages of the fabrication process has been and subsequent cyclic oxidation is presented, and the relevant interdiffusion and phase equilibria issues in are discussed. Evaluation of the oxidation behavior of these Ru-modified bond coat structures reveals that each B2 interlayer arrangement leads to the formation of α-Al 2 O 3 TGO at 1100°C, but the durability of the TGO is somewhat different and in need of further improvement in both cases

    Ultimate gravitational mass defect

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    We present a new type of gravitational mass defect in which an infinite amount of matter may be bounded in a zero ADM mass. This interpolates between effects typical of closed worlds and T-spheres. We consider the Tolman model of dust distribution and show that this phenomenon reveals itself for a solution that has no origin on one side but is closed on the other side. The second class of examples corresponds to smooth gluing T-spheres to the portion of the Friedmann-Robertson-Walker solution. The procedure is generalized to combinations of smoothly connected T-spheres, FRW and Schwarzschild metrics. In particular, in this approach a finite T-sphere is obtained that looks for observers in two R-regions as the Schwarzschild metric with two different masses one of which may vanish.Comment: 9 pages. 1 reference added. To appear in Gen. Rel. Gra

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