9,377 research outputs found

    Cost competitiveness of a solar cell array power source for ATS-6 educational TV terminal

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    A cost comparison is made between a terrestrial solar cell array power system and a variety of other power sources for the ATS-6 Satellite Instructional Television Experiment (SITE) TV terminals in India. The solar array system was sized for a typical Indian location, Lahore. Based on present capital and fuel costs, the solar cell array power system is a close competitor to the least expensive alternate power system. A feasibility demonstration of a terrestrial solar cell array system powering an ATS-6 receiver terminal at Cleveland, Ohio is described

    Magnetic field mapper

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    Magnetic field mapper locates imperfections in cadmium sulphide solar cells by detecting and displaying the variations of the normal component of the magnetic field resulting from current density variations. It can also inspect for nonuniformities in other electrically conductive materials

    Solar energy meter

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    An instrument was developed to continually integrate the energy available in incident light on a specifically oriented surface. The unit was designed for outdoor use in remote locations and is capable of operation over a temperature range of -20 to +60 C with good accuracy. The unit is weather resistant, requires low power, has a high input impedance, is inexpensive, and has a visual readout and an analog output for recording

    Investigation of deep flaws in thin walled tanks

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    Growth of deep surface flaws in thin wall tanks of aluminum and titanium base metal

    Linkages between Market Participation and Productivity: Results from a Multi-Country Farm Household Sample

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    We build upon international trade literature to analyze the direction of causality between market participation and productivity. Cross-country household data from Tanzania, Vietnam and Guatemala are used in a 2SLS approach with market participation and productivity as endogenous variables. Results indicate that households with higher productivity tend to participate in agricultural markets regardless of market access factors. In contrast, having better market access does not necessarily lead to higher productivity. This finding suggests that investments in market access infrastructure provide minimal, if any, improvements in agricultural productivity; whereas programs targeted at enhancements in farm structure and capital have the potential to increase both productivity and market participation.International Relations/Trade, Marketing, Productivity Analysis,

    Conscious monitoring and control (reinvestment) in surgical performance under pressure.

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    Research on intraoperative stressors has focused on external factors without considering individual differences in the ability to cope with stress. One individual difference that is implicated in adverse effects of stress on performance is "reinvestment," the propensity for conscious monitoring and control of movements. The aim of this study was to examine the impact of reinvestment on laparoscopic performance under time pressure

    Fracture characteristics of structural aerospace alloys containing deep surface flaws

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    Conditions controlling the growth and fracture of deep surface flaws in aerospace alloys were investigated. Static fracture tests were performed on 7075-T651 and 2219-T87 aluminum, and 6Ai-4V STA titanium . Cyclic flaw growth tests were performed on the two latter alloys, and sustain load tests were performed on the titanium alloy. Both the cyclic and the sustain load tests were performed with and without a prior proof overload cycle to investigate possible growth retardation effects. Variables included in all test series were thickness, flaw depth-to-thickness ratio, and flaw shape. Results were analyzed and compared with previously developed data to determine the limits of applicability of available modified linear elastic fracture solutions

    APP Expression in Primary Neuronal Cell Cultures fromP6 Mice during in vitro Differentiation

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    Primary neuronal cell cultures from P6 mice were investigated in order to study amyloid protein precursor (APP) gene expression in differentiating neurons. Cerebellar granule cells which strongly express APP 695 allowed the identification of three distinct isoforms of neuronal APP 695. The high-molecular-weight form of APP 695 is sialylated. The expression pattern of neuronal APP 695 changes during in vitro differentiation. Sialylated forms become more abundant upon longer cultivation time. The secreted forms of sialylated, neuronal APP 695 are shown to comigrate with APP isolated from cerebrospinal fluid. We suggest that the different sialylation states of APP 695 may reflect the modulation of cell-cell and cell-substrate interactions during in vitro differentiation and regeneration

    An Empirical Approach to Cosmological Galaxy Survey Simulation: Application to SPHEREx Low-Resolution Spectroscopy

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    Highly accurate models of the galaxy population over cosmological volumes are necessary in order to predict the performance of upcoming cosmological missions. We present a data-driven model of the galaxy population constrained by deep 0.1-8 μm\rm \mu m imaging and spectroscopic data in the COSMOS survey, with the immediate goal of simulating the spectroscopic redshift performance of the proposed SPHEREx mission. SPHEREx will obtain over the full-sky R41R\sim41 spectrophotometry at moderate spatial resolution (6"\sim6") over the wavelength range 0.75-4.18 μm\rm \mu m and R135R\sim135 over the wavelength range 4.18-5 μm\rm \mu m. We show that our simulation accurately reproduces a range of known galaxy properties, encapsulating the full complexity of the galaxy population and enables realistic, full end-to-end simulations to predict mission performance. Finally, we discuss potential applications of the simulation framework to future cosmology missions and give a description of released data products

    The effect of surgical approach on the histology of the femoral head following resurfacing of the hip : analysis of retrieval specimens

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    Objectives: We aimed to determine the effect of surgical approach on the histology of the femoral head following resurfacing of the hip. Methods: We performed a histological assessment of the bone under the femoral component taken from retrieval specimens of patients having revision surgery following resurfacing of the hip. We compared the number of empty lacunae in specimens from patients who had originally had a posterior surgical approach with the number in patients having alternative surgical approaches. Results: We found a statistically significant increase in the percentage of empty lacunae in retrieval specimens from patients who had the posterior approach compared with other surgical approaches (p < 0.001). Conclusions: This indicates that the vascular compromise that occurs during the posterior surgical approach does have long-term effects on the bone of the femoral head, even if it does not cause overt avascular necrosis
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