12,874 research outputs found

    Pollution reduction technology program for turboprop engines

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    The reduction of CO, HC, and smoke emissions while maintaining acceptable NO(x) emissions without affecting fuel consumption, durability, maintainability, and safety was accomplished. Component combustor concept screening directed toward the demonstration of advanced combustor technology required to meet the EPA exhaust emissions standards for class P2 turboprop engines was covered. The combustion system for the Allison 501-D22A engine was used, and three combustor design concepts - reverse flow, prechamber, and staged fuel were evaluated

    An experimental test of Rubinstein's bargaining model

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    This paper offers an experimental test of a version of Rubinstein’s bargaining model in which the players’ discount factors are unequal. We find that learning, rationality, and fairness are all significant in determining the outcome. In particular, we find that a model of myopic optimization over time predicts the sign of deviations in the opening proposal from the final undiscounted agreement in the previous period rather well. To explain the amplitude of the deviations, we then successfully fit a perturbed version of the model of myopic adjustment to the data that allows for a bias toward refusing inequitable offers

    Pneumatic shutoff and time-delay valve operates at controlled rate

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    Shutoff and time delay valve, which incorporates a metering spool that moves at constant velocity under pneumatic pressure and spring compression, increases fluid-flow area at a uniform rate. Diaphragm areas, control cavity volume, and bleed-orifice size may be varied to give any desired combination of time delay and spool travel time

    Analytical study of the frequency response function of a nonlinear spring damper system

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    A spring damper system with a nonlinear damping element is investigated using the Volterra series method to study the system frequency response function (FRF) characteristics. The relationship between the FRF and the characteristic parameters of the nonlinear damper is determined to produce an analytical description for the system FRF. Simulation studies are used to verify the theoretical analysis. These results provide an important basis for the FRF based analysis and design of nonlinear spring damper systems in the frequency domain

    Electron Interactions and Transport Between Coupled Quantum Hall Edges

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    We examine the effects of electron-electron interactions on transport between edge states in a multilayer integer quantum Hall system. The edge states of such a system, coupled by interlayer tunneling, form a two-dimensional, chiral metal at the sample surface. We calculate the temperature-dependent conductivity and the amplitude of conductance fluctuations in this chiral metal, treating Coulomb interactions and disorder exactly in the weak-tunneling limit. We find that the conductivity increases with increasing temperature, as observed in recent experiments, and we show that the correlation length characterising conductance fluctuations varies inversely with temperature.Comment: 4 pages, 2 figures, typos corrected, Ref. 17 added, minor changes made for publicatio

    Including the urban heat island in spatial heat health risk assessment strategies: a case study for Birmingham, UK

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    Background Heatwaves present a significant health risk and the hazard is likely to escalate with the increased future temperatures presently predicted by climate change models. The impact of heatwaves is often felt strongest in towns and cities where populations are concentrated and where the climate is often unintentionally modified to produce an urban heat island effect; where urban areas can be significantly warmer than surrounding rural areas. The purpose of this interdisciplinary study is to integrate remotely sensed urban heat island data alongside commercial social segmentation data via a spatial risk assessment methodology in order to highlight potential heat health risk areas and build the foundations for a climate change risk assessment. This paper uses the city of Birmingham, UK as a case study area. Results When looking at vulnerable sections of the population, the analysis identifies a concentration of "very high" risk areas within the city centre, and a number of pockets of "high risk" areas scattered throughout the conurbation. Further analysis looks at household level data which yields a complicated picture with a considerable range of vulnerabilities at a neighbourhood scale. Conclusions The results illustrate that a concentration of "very high" risk people live within the urban heat island, and this should be taken into account by urban planners and city centre environmental managers when considering climate change adaptation strategies or heatwave alert schemes. The methodology has been designed to be transparent and to make use of powerful and readily available datasets so that it can be easily replicated in other urban areas

    Strategic planning for bioanalytical automation: managing growth successfully

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    Bioanalytical automation expanded at Glaxo Inc. from 1987 to 1991 by cycling through periods of justification, planning, implementation, obstacle-jumping and success, which justified continued cycling. In 1990 it became evident that the technology and its growth needed to be planned and the resources had to be managed. A Strategic Plan was researched and prepared. The plan describes the mission, values, goals and structure of the Bioanalytical Automation Group and the most important requirements for achieving those planned goals, including: (1) Long-term management commitment; (2) Trained, dedicated personnel; (3) Quality facilities; (4) Teamwork; and (5) Investment in automationcompatible equipment. The strategic plan has been in effect for over a year; current status, history, and the future are discussed in this article

    The Relationship of Delinquency to Achievement

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    Studies have shown that juvenile delinquents are at risk for a wealth of other problems such as learning disabilities. below average intelligence, and attention deficit disorder. Some researchers have refuted these claims by saying that the difficulty in appropriately labeling individuals learning disabled and delinquent has resulted in increasing numbers of individuals being incorrectly labeled delinquent or learning disabled. Others have argued that differential treatment of learning disabled and delinquent youth has negatively affected the school performance of these individuals. This study examined the Reading, Math, and English achievement scores of both delinquents and nondelinquents in an attempt to determine whether a significant mean difference between these groups was present. Seventy-three participants, including twenty-nine delinquents and fifty-two nondelinquents, were assessed through the use of the Tests of Adult Basic Education (TABE). At-test was performed, and it was found that there were no significant mean differences between these two groups with regard to Reading and English scores; a significant mean difference in Math scores was found between these two groups
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