Theses and Dissertations from UMD

Permanent URI for this communityhttp://hdl.handle.net/1903/2

New submissions to the thesis/dissertation collections are added automatically as they are received from the Graduate School. Currently, the Graduate School deposits all theses and dissertations from a given semester after the official graduation date. This means that there may be up to a 4 month delay in the appearance of a give thesis/dissertation in DRUM

More information is available at Theses and Dissertations at University of Maryland Libraries.

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2008 - 200912020 - 20231

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    Development of the Cold Atom Vacuum Standard
    (2023) Scherschligt, Julia; Porto, Trey; Rolston, Steven; Physics; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    We describe the inception, design, development, and initial results of The Cold Atom Vacuum Standard (CAVS). It has been known for many years that vacuum level limits the lifetime of a cold atom cloud; we invert this to create a vacuum pressure measurement tool based on the trapped cloud lifetime. The difference between a standard and a sensor is of great concern to metrologists: a primary standard defines a unit, and a sensor transduces it. To have a device capable of both functions is to have a calibration-free measurement tool, which is of interest to many stakeholders in academia, industry, and defense. We describe all aspects of construction of the CAVS, including a lengthy investigation of vacuum technology. We ultimately demonstrate that the device is traceable to pressure through the fundamental physics of collision cross sections, thereby elevating it to status as not just a sensor, but a standard.
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    An Analysis of Vehicle Fires and Potential Methods to Reduce Their Severity Through More Stringent Material Standards
    (2008-06-17) Patronik, Evan; Mowrer, Frederick; Fire Protection Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    In the United States, more than 1 in every 12 fire fatalities occurs in a passenger road vehicle; vehicle fires claim roughly 1200 injuries, $1.3 billion in property loss, and 490 lives annually. Very little progress has been made over the last several decades to confront the hazards of vehicle fires, but recently researchers and standards organizations have begun addressing these challenges. A literature review of the progress made and methods of reducing fire severity through technologies and standards was conducted. NFPA 556 is one proposed standard aimed at mitigating the hazards to occupants of vehicle fires; it was used to analyze the fire retardancy of a new, fire-resistant acoustic insulation material through small, bench, and large-scale testing. The feasibility of the use of this material in new vehicles for the reduction of losses was assessed through a cost-benefit analysis. Upon review of the results, it was determined that the new insulation did not pass all the requirements of NFPA 556. However, the standard does include stringent requirements, so the improved performance of the material should not be underappreciated. Based on the literature search and experiments, this standard, in combination with other fire protection technologies, provides a basis for improved vehicle fire safety.