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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Identifying Relevant Variables for Understanding How School Facilities Affect Educational Outcomes

Bosch, Sheila Jones 07 January 2004 (has links)
Many school facilities in the United States are old, out-of-date, poorly maintained, and lack specific design elements that are likely to enhance teaching, learning, behavior, and other desirable outcomes. This study proposed that one reason why previous research regarding the effects of the physical school environment on educational outcomes has had little impact on the quality of schools is because there is a lack of knowledge about these relationships. A multi-method approach was used to solicit information from educators and researchers familiar with school facility effects literature to develop a set of research priorities to guide future research. In Phase I, a literature analysis provided important physical and outcome variables to seed brainstorming lists used in following phases of the research and provided the basis for a gap analysis to identify unavailable information. A concept mapping methodology was utilized in Phase II to solicit feedback from a group of seventeen experienced educators who were asked to brainstorm a list of measures of student, school, or school district success, sort their final list of more than 100 items into categories that made sense to them, and rate each item regarding how important it is to monitor or otherwise track. Using a Delphi method, a series of four questionnaires was given to a group of experienced researchers who developed a list of physical variables plausibly related to educational outcomes, rated the importance of those items, developed hypotheses that included top-rated physical variables and top-rated outcome variables (i.e., measures of success rated by educators), and then selected from those hypotheses several that became the basis of the recommended research priorities for the field. These research priorities propose investigations of the relationships between a set of physical variables (including the provision of team work stations and faculty collaborative spaces, well-designed circulation spaces, spaces for quiet reflection, adaptable seating, daylighting in classrooms, and overall maintenance and building quality) and a variety of educational outcomes (e.g., achievement, behavior, satisfaction, affective performance).
2

Facility effects on Helicon ion thruster operation

Caruso, Natalie R. S. 27 May 2016 (has links)
In order to enable comparison of Helicon ion thruster performance across different vacuum test facilities, an understanding of the effect of operating pressure on plasma plume properties is required. Plasma property measurements are compared for thruster operation at two separate vacuum facility operating pressures to determine the effect of neutral ingestion on Helicon ion thruster operation. The ion energy distribution function (IEDF), electron temperature, ion number density, and plasma potential are measured along the thruster main axis for a replica of the Madison Helicon eXperiment. Plasma property values recorded at the ‘high-pressure condition’ (3.0×10^(-4) Torr corrected for argon) are compared to values recorded at the ‘low-pressure condition’ (1.2×10^(-5) Torr corrected for argon) for thruster operation at 100 - 500 watts radio frequency forward power, 340 – 700 gauss source region magnetic field strength, and 1.3 - 60 sccm argon volumetric flow rate (0.039-1.782 mg/s). Differences in plasma behavior at the ‘high-pressure condition’ result from two primary neutral-plume interactions: collisions between accelerated beam ions and ingested neutrals leading to a reduction of ion energy and neutral ionization downstream of the thruster exit due to electron-neutral collisions. Electron temperature at higher operating pressures is lowered due to an electron cooling effect resulting from repeated collisions with neutral atoms. Results suggest that Helicon ion thruster plasma properties are greatly influenced when subjected to neutral ingestion.

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