26,658 research outputs found

    Unmanned seismometer levels self, corrects drift errors

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    Four-component, three-axis, feedback-controlled seismograph incorporates electronic circuitry for leveling and for monitoring the feedback signal required for servo-centering. Viscous damping of the earth-motion signal, compensation of the residual long-term drift, and centering of the seismometers are provided by automatic mechanisms

    On optical imaging through aircraft turbulent boundary layers

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    Optical resolution quality as affected by aircraft turbulent boundary layers is analyzed. Wind-tunnel data was analyzed to obtained the variation of boundary layer turbulence scale length and mass density rms fluctuations with Mach number. The data gave good agreement with a mass density fluctuation turbulence spectrum that is either isotropic of orthogonally anisotropic. The data did not match an isotropic turbulence velocity spectrum which causes an anisotropic non-orthogonal mass density fluctuation spectrum. The results indicate that the average mass density rms fluctuation is about 10% of the maximum mass density across the boundary layer and that the transverse turbulence scale size is about 10% of the boundary layer thickness. The results indicate that the effect of the turbulent boundary layer is large angle scattering which decreases contrast but not resolution. Using extinction as a criteria the range of acceptable aircraft operating conditions are given

    The case of Heinrich Wilhelm Poll (1877-1939): A German-Jewish geneticist, eugenicist, twin researcher, and victim of the Nazis

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    This paper uses a reconstruction of the life and career of Heinrich Poll as a window into developments and professional relationships in the biological sciences in Germany in the period from the beginning of the twentieth century to the Nazi seizure of power in 1933. Poll's intellectual work involved an early transition from morphometric physical anthropology to comparative evolutionary studies, and also found expression in twin research - a field in which he was an acknowledged early pioneer. His advocacy of eugenics led to participation in state-sponsored committees convened to advise on social policy, one of which debated sterilisation and made recommendations that led eventually to the establishment of the notorious Kaiser Wilhelm Institute for Anthropology, Human Heredity and Eugenics. However, his status as a prominent geneticist and, in particular, as a eugenicist had an ironic and ultimately tragic dimension. Heinrich Poll was of Jewish birth, and this resulted in his career being destroyed by an application of the population policies he had helped put in place

    New records for Tephritidae (Diptera) in Great Smoky Mountains National Park

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    As part of the All Taxon Biological Inventory (ATBI) being conducted in the Great Smoky Mountains National Park (GSMNP), we report new distribution and host plant records for nine Tephritidae species

    Defrauding the Public Interest: A Critical Examination of Reengineered Audit Processes and the Likelihood of Detecting Fraud

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    In the past few years, most of the major international public accounting firms have reengineered their audit processes to improve the cost effectiveness of completing an audit and to focus on value-added services for clients. The reengineered audit processes generally focus on a client’s business processes and the information systems used by the client to generate financial information. In essence, the new audit approaches deemphasize direct testing of the underlying transactions and account balances. Such an approach emphasizes analytical procedures as the main source of substantive evidence. During this same time period, however, the profession (through the AICPA) explicitly acknowledged the profession’s responsibility for fraud detection. The main premise of this paper is that the increased emphasis on systems assessments is at odds with the profession’s position regarding fraud detection because most material frauds originate at the top levels of the organization, where controls and systems are least prevalent and effective. As such, the profession may be paying lip service to fraud detection, while at the same time changing the audit process in a manner that is less effective at detecting the most common frauds

    What may be learnt about the archaeology of islands from archaeologically derived models of the exploration of Polynesia, 1966-2001?

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    Polynesian archaeology is one regional specialization in the world-wide practice of archaeological investigations of islands, oceans and seas. It is timely to consider how Polynesian archaeology fits within that newly-articulated framework of theoretical and methodological advances concerned with islands. To do this, I examine the history of archaeologically-derived models of the exploration of Polynesia developed since the invention of radiocarbon dating

    The MSFC space station/space operations mechanism test bed

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    The Space Station/Space Operations Mechanism Test Bed consists of the following: a hydraulically driven, computer controlled Six Degree-of-Freedom Motion System (6DOF); a six degree-of-freedom force and moment sensor; remote driving stations with computer generated or live TV graphics; and a parallel digital processor that performs calculations to support the real time simulation. The function of the Mechanism Test Bed is to test docking and berthing mechanisms for Space Station Freedom and other orbiting space vehicles in a real time, hardware-in-the-loop simulation environment. Typically, the docking and berthing mechanisms are composed of two mating components, one for each vehicle. In the facility, one component is attached to the motion system, while the other component is mounted to the force/moment sensor fixed in the support structure above the 6DOF. The six components of the contact forces/moments acting on the test article and its mating component are measured by the force/moment sensor

    Phosphonium chloride for thermal storage

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    Development of systems for storage of thermal energy is discussed. Application of phosphonium chloride for heat storage through reversible dissociation is described. Chemical, physical, and thermodynamic properties of phosphonium chloride are analyzed and dangers in using phosphonium chloride are explained

    Regenerable metallic oxide systems for removal of carbon dioxide: A concept

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    Design concepts for portable canisters for removal of carbon dioxide are described. One is screen pack configuration consisting of brazed rectangular canister with four metal oxide packs inserted. Other is radial flow canister with perforated central tube. Methods of production and operating principles are presented

    The Feynman-Wilson gas and the Lund model

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    We derive a partition function for the Lund fragmentation model and compare it with that of a classical gas. For a fixed rapidity ``volume'' this partition function corresponds to a multiplicity distribution which is very close to a binomial distribution. We compare our results with the multiplicity distributions obtained from the JETSET Monte Carlo for several scenarios. Firstly, for the fragmentation vertices of the Lund string. Secondly, for the final state particles both with and without decays.Comment: Latex, 21+1 pages, 11 figure
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