4,270 research outputs found

    Computational analysis and preliminary redesign of the nozzle contour of the Langley hypersonic CF4 tunnel

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    A computational analysis, modification, and preliminary redesign study was performed on the nozzle contour of the Langley Hypersonic CF4 Tunnel. This study showed that the existing nozzle was contoured incorrectly for the design operating condition, and this error was shown to produce the measured disturbances in the exit flow field. A modified contour was designed for the current nozzle downstream of the maximum turning point that would provide a uniform exit flow. New nozzle contours were also designed for an exit Mach number and Reynolds number combination which matches that attainable in the Langley 20-Inch Mach 6 Tunnel. Two nozzle contours were designed: one having the same exit radius but a larger mass flow rate than that of the existing CF4 Tunnel, and the other having the same mass flow rate but a smaller exit radius than that of the existing CF4 Tunnel

    National Purpose;Note

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    National Purpose;Note

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    An investigation of the science content preparation of Iowa State University elementary education majors: relationships among secondary and college course backgrounds, attitude toward teaching science, science teaching efficacy, science misconceptions, and science achievement

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    The goal of this study was to explore the role that formal science content education plays in the process of educating future elementary teachers of science. The formal science content preparation of elementary education majors was investigated to explore the relationships between secondary school and college science content preparation and science achievement, attitude toward teaching science, science teaching efficacy, selected science misconceptions, and other demographic variables. Some of the instruments utilized included Enoch\u27s and Rigg\u27s Science Teaching Efficacy Belief Instrument Form B, Thompson\u27s and Shrigley\u27s Revised Science Attitude Scale, the ACT Science Reasoning Test, student constructed concept maps, and a demographics questionnaire;Although a number of statistically significant relationships were found to exist among the variables, the significant correlations were mainly in what might be classified as low to moderate ranges of correlation;The results of this research can be drawn upon to make recommendations and set strategies for policy makers to consider when determining how to best prepare elementary education majors to teach science

    Fitness landscapes investigated

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    AICPA-NASBA Committee on Professional Recognition and Regulation, Report to Spring Meeting of Council, May3, 1972

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    https://egrove.olemiss.edu/aicpa_assoc/2090/thumbnail.jp

    Urgency of Unity, Remarks at AICPA Council Meeting, May 5, 1969

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    https://egrove.olemiss.edu/aicpa_assoc/2091/thumbnail.jp

    Measuring Student Growth in K–12 Schools Using Item Response Theory Within Structural Equation Models

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    The use of test-based accountability has expanded beyond measurements of school effectiveness to include measurements of teacher effectiveness. However, whereas the use of test-based accountability has expanded, the understanding of the statistical methodologies used in accountability systems has not kept pace. Currently, Student Growth Percentiles and value-added modeling are the most prevalent methodologies for estimating annual student growth. Each of these methodologies is regression-based and relies on scale scores from standardized assessments. Given the prevalence of Item Response Theory in statewide assessment programs, these scale scores often result from Item Response Theory scaling practices. Grounded in earlier work of Brockman (2011), Chiu and Camilli (2013), and Lu, Thomas, and Zumbo (2005), concerning error related to Item Response Theory-based scale scores, this study considers using Item Response Theory as the measurement model in a structural equation model by including simulated item response patterns as indicators of ability. Data were simulated using parameters from the Mississippi Curriculum Test, Second Edition. Separate structural equation models for language arts and mathematics were considered. Upon examining the fit of each model, results indicated a good fit for the measurement model in language arts and in mathematics. Results also indicated a good fit for the overall structural equation model but none of the structural relationships were statistically significant. Additional results and implications of this study are discussed
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