2 resultados para Significant Impact Loading

em DRUM (Digital Repository at the University of Maryland)


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School districts need to “build the bench” to ensure that their schools will have effective principals when vacancies arise (Johnson-Taylor & Martin, 2007). Assistant principals represent a potential pool of new school leaders who are prepared to move confidently into the principalship (Oliver, 2005). Although a critical leader in schools, the assistant principal position is underutilized and under-researched (Oleszewski, Shoho, & Barnett, 2012). This lack of focus on assistant principals is concerning because they are part of the school leadership team and often advance to the position of school principal. The purpose of this study was to examine the impact of Bay City Public Schools’ (a pseudonym) Aspiring Principals Preparation Program (AP3; also a pseudonym) on assistant principals’ learning-centered leadership behaviors, as assessed by the Vanderbilt Assessment of Leadership in Education (Val-Ed) survey. The study compared the Val-Ed scores of assistant principals who had participated in one of three cohorts of AP3 training to the scores of assistant principals who did not participate. The results indicated that participation in the AP3 had no significant impact on respondents’ learning-centered leadership behaviors, as assessed on the VAL-ED instrument. This study may be useful as the district seeks to validate the effectiveness of AP3 and identify potential refinements and program modifications.

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This dissertation focuses on design challenges caused by secondary impacts to printed wiring assemblies (PWAs) within hand-held electronics due to accidental drop or impact loading. The continuing increase of functionality, miniaturization and affordability has resulted in a decrease in the size and weight of handheld electronic products. As a result, PWAs have become thinner and the clearances between surrounding structures have decreased. The resulting increase in flexibility of the PWAs in combination with the reduced clearances requires new design rules to minimize and survive possible internal collisions impacts between PWAs and surrounding structures. Such collisions are being termed ‘secondary impact’ in this study. The effect of secondary impact on board-level drop reliability of printed wiring boards (PWBs) assembled with MEMS microphone components, is investigated using a combination of testing, response and stress analysis, and damage modeling. The response analysis is conducted using a combination of numerical finite element modeling and simplified analytic models for additional parametric sensitivity studies.