50,079 research outputs found

    Field tests of the real-data acquisiton system for the NASA-LaRC differential absorption lidar

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    A data acquisition system (DAS) for the NASA/LaRC Differential Absorption Lidar (DIAL) was documented. This DAS is a dual LSI 11/23 set up where one computer retrieves data from the digitizers and other peripheral units, stores that data on magnetic tape, generates aerosol grayscales on a Trilog printer and passes data to the second computer. The second computer is dedicated to real time displays of the data in a variety of modes from raw data to range resolved ozone profiles. The DIAL DAS also has several new features

    An object-oriented model of measurement systems

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    This paper presents a general object-oriented model for measurement systems. The limitations of the conventional function-oriented models are examined in the light of the generalized concept of measurement and its theoretical framework proposed previously by the authors. The proposed model identifies five classes of objects, i.e., measured object, measuring instrument, reference standard, human observer, and operating environment. Each is characterized by its own attributes and operations or functions at three levels, i.e., internal, operational, and environmental. The interactions between them are also modeled, including the coupling between the measured object and the measuring instrument, the human-instrument interface, the calibration, and the interference. It serves as both a modeling framework and a practical tool for description, analysis and design, and, in particular, for computer-aided analysis and design of a measuring system. It will find applications in instrumentation engineering and measurement research and education

    Can tract element distributions reclaim tectonomagmatic facies of basalts in greenstone assemblages?

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    During the past two decades many words have been written both for and against the hypothesis that the tectonic setting of a suite of igneous rocks is retained by the chemical variability within the suite. For example, it is argued that diagrams can be constructed from modern/recent basalt subcompositions within the system Ti-Zr-Y-Nb-Sr such that tectonomagmatic settings can be reclaimed. If one accepts this conclusion, it is tempting to inquire as to how far this hypothesis can be extended into other petrological realms. If chemical variations of metabasalts retain information relating to their genesis (tectonic setting), for example, this would be most helpful in reconstructing the history of basalts from greenstone belts. A discussion follows

    The Penn Science Teacher Institute: A Proven Model

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    The University of Pennsylvania’s Master of Chemistry Education (MCE) program graduated five cohorts of approximately twenty teachers between 2002 and 2006. One year after the teachers in the last cohort earned their degrees, the Penn Science Teacher Institute (Penn STI) initiated a follow-up study to ascertain if the goals of the MCE program had been sustained. For example, were the teachers incorporating updated content knowledge into their lessons and were their students learning more chemistry? A total of seventy-four of the eighty-two graduates participated in some aspect of this study. Because baseline data were not available for the MCE teachers and their students, baseline data from a comparable group of chemistry teachers enrolled in the first cohort of the Penn STI program and their students were used in some analyses. Among other findings, the data indicate that MCE met its goals: 1) to improve the chemistry content knowledge of its teacher participants; 2) to increase the use of research-based instruction in their classrooms; and, 3) to improve student achievement in chemistry (students of MCE graduates scored significantly higher than the comparison group)

    Development and operation of a real-time data acquisition system for the NASA, Langley Research Center Differential Absorption Lidar

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    The capabilities of the DIAL data acquisition system (DAS) for the remote measurement of atmospheric trace gas concentrations from ground and aircraft platforms were extended through the purchase and integration of other hardware and the implementation of improved software. An operational manual for the current system is presented. Hardware and peripheral device registers are outlined only as an aid in debugging any DAS problems which may arise

    Modelling and measurement accuracy enhancement of flue gas flow using neural networks

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    This paper discusses the modeling of the flue gas flow in industrial ducts and stacks using artificial neural networks (ANN's). Based upon the individual velocity and other operating conditions, an ANN model has been developed for the measurement of the volume flow rate. The model has been validated by the experiment using a case-study power plant. The results have shown that the model can largely compensate for the nonrepresentativeness of a sampling location and, as a result, the measurement accuracy of the flue gas flow can be significantly improved

    Outport adaptations: Social indicators through Newfoundland\u27s Cod crisis

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    The 1992 moratorium on fishing for Northern Cod marked a symbolic end to the way of life that had sustained Newfoundland\u27s out ports for hundreds of years. It also marked the completion of an ecological regime shift, from an ocean ecosystem dominated by cod and other predatory ground fish, to one in which such fish are comparatively scarce, and lower-trophic-level invertebrates more common. We examine patterns of change seen in large-scale social indicators, which reflect the smaller-scale adaptations of individuals and communities during this ecological shift. Trends in population, migration, age, unemployment and dependency suggest declining conditions in rural Newfoundland over the years of fisheries troubles. The 1992 crisis accelerated previous trends, but did not produce great discontinuities. Some trends date instead to the late-1980s resource-depletion phase that ended the glory years of Newfoundland\u27s ground fish boom. Government interventions meant to soften the economic impact of the 1992 crisis also blunted its social impacts, effectively postponing or distributing these over a number of subsequent years. Out port society is adapting to shifts in the regulatory and global-market environment, as well as changing marine ecology. Adaptive strategies include new investments in invertebrate fisheries, changes in education and migration, and continuing reliance on the informal economy

    Editorial: Throwing Shoes

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