7,273 research outputs found

    Digging into the infrastructure debate

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    Infrastructure (Economics)

    Investigation of the aerodynamic characteristics of a lifting body in ground proximity

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    The use of cambered hull shapes in the next generation of lighter-than-air vehicles to enhance aerodynamic performance, together with optimized take-off manoeuvre profiles, will require a more detailed understanding of ground proximity effects for such aircraft. A series of sub-scale wind tunnel tests at Re = 1.4 x 106 on a 6:1 prolate spheroid are used to identify potential changes in aerodynamic lift, drag and pitching moment coefficients that are likely to be experienced on the vehicle hull in isolation when in close ground proximity. The experimental data is supported by a preliminary assessment of surface pressure changes using a high order panel method (PANAIR) and RANS CFD simulations to assess the flow structure. The effect of ground proximity, most evident when non-dimensional ground clearance (h/c) < 0.3, is to reduce lift coefficient, increase drag coefficient and increase the body pitching moment coefficient

    A Response Surface Methodology Study of Ferroelectric Memory Devices

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    Fatigue in ferroelectric memory devices was studied. The application of fatigue pulses to a ferroelectric sample was controlled by the RT-66 Ferroelectric Tester, a variation of the Sawyer-Tower circuit. The RT-66 also controlled data collection following the fatiguing process. Seven variables were evaluated for their potential- affect on fatigue. A sequence of fatigue tests, which varied the settings of these variables, was developed using Response Surface Methodology (RSM) experimental designs. Least-squares regression models were developed once a particular RSM set of design experiments was completed. These models were evaluated using RSM tools, and the analysis of these models allowed the iterative development of new RSM designs. Within the experimental operating region it was determined that aging did not affect fatigue, and that differences in ferroelectric materials and electrode materials were the most important factors in determining fatigue. First-order models failed to fit the data for any of the RSM designs. The final model developed had two pure quadratic terms and three first-order terms. However, this design only involved one type of ferroelectric. Further testing is necessary before the findings of this study can be extended to modeling fatigue in other ferroelectric materials

    A study of the influence of the internal politics of the Royal Navy on the conduct of the war against the French Republic

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    Contrary to the myth of invincibility which frequently enshrouds the history of the Royal Navy, there was no particular reason to cause an observer to predict a British victory in the War against the French Republic. At the outbreak of the war, England had a smaller navy than France. In addition, France had won the most recent war between the two countries. Finally, France was obviously a larger, stronger, more populous country than England. Yet England won all the naval battles. This is due in part ot the weaknesses of the French navy caused by the French Revolution. But more important, it is due to the officers of the British navy

    All Purpose Mobile GPS

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    The aim of the All Purpose Mobile GPS (The System) is to create a GPS tracking device that can accurately record location and calculate velocity, distance traveled and elevation change even when the satellite signal is lost. This data can later overlay on existing internet-based maps illustrating a trip to oneself or others. The portable tracker consumes very little power achieving several days’ worth of power in a single charge. A solar cell provides a quick battery boost in a pinch. SD Card storage increases compatibility with computers and other forms of data transfer. Data processing, such as viewing the route on a map, occurs on a computer after the completed data logging

    Physiology and political beliefs: A response to Knoll, O’Daniel, and Cusato

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    n a recent paper in this journal, Knoll et al. question three studies from our laboratory. In this response to that paper, we address deficiencies in their “reproduction.” Notably, we demonstrate that their data provide little evidence of a negativity bias among research subjects, suggesting a failure not only to reproduce findings from our earlier studies, but also a failure to find a widely acknowledged universal human physiological response trait. This situation raises a number of questions regarding the data on which their analyses are based. We explore these questions below and speculate that Knoll et al.’s data collection procedures may compromise their ability to speak to the external validity of earlier studies

    Integrated Rig for the Production of Boron Nitride Nanotubes via the Pressurized Vapor-Condenser Method

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    An integrated production apparatus for production of boron nitride nanotubes via the pressure vapor-condenser method. The apparatus comprises: a pressurized reaction chamber containing a continuously fed boron containing target having a boron target tip, a source of pressurized nitrogen and a moving belt condenser apparatus; a hutch chamber proximate the pressurized reaction chamber containing a target feed system and a laser beam and optics

    Economic resilience and crowdsourcing platforms

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    The increased interdependence and complexity of modern societies have increased the need to involve all members of a community into solving problems. In times of great uncertainty, when communities face threats of different kinds and magnitudes, the traditional top-down approach where government provides solely for community wellbeing is no longer plausible. Crowdsourcing has emerged as an effective means of empowering communities with the potential to engage individuals in innovation, self-organization activities, informal learning, mutual support, and political action that can all lead to resilience. However, there remains limited resource on the topic. In this paper, we outline the various forms of crowdsourcing, economic and community resilience, crowdsourcing and economic resilience, and a case study of the Nepal earthquake. his article presents an exploratory perspective on the link can be found between crowdsourcing and economic resilience. It introduces and describes a framework that can be used to study the impact of crowdsourcing initiatives for economic resilience by future research. An initial a set of indicators to be used to measure the change in the level of resilience is presented.info:eu-repo/semantics/publishedVersio

    Design of a cooperative problem-solving system for enroute flight planning: An empirical study of its use by airline dispatchers

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    In a previous report, an empirical study of 30 pilots using the Flight Planning Testbed was reported. An identical experiment using the Flight Planning Testbed (FPT), except that 27 airline dispatchers were studied, is described. Five general questions were addressed in this study: (1) under what circumstances do the introduction of computer-generated suggestions (flight plans) influence the planning behavior of dispatchers (either in a beneficial or adverse manner); (2) what is the nature of such influences (i.e., how are the person's cognitive processes changed); (3) how beneficial are the general design concepts underlying FPT (use of a graphical interface, embedding graphics in a spreadsheet, etc.); (4) how effective are the specific implementation decisions made in realizing these general design concepts; and (5) how effectively do dispatchers evaluate situations requiring replanning, and how effectively do they identify appropriate solutions to these situations
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