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No description available.

No description available.

Surface Acoustic Wave (SAW) devices are manufactured using standard metallization and photolithographic techniques that have been established by the semiconductor industry. The facilities in the newly developed Microelectronics laboratory at the University of Central Florida will be utilized in the fabrication of a SAW device. This thesis will outline the complete procedure beginning with the initial design from given specifications, up to mask generation, fabricating and testing of the device. This will serve to calibrate the fabrication process for future work in SAW device and semiconductor fabrication. The models that are used in the SAWCAD design software will be verified by comparing the theoretical and experimental results.

Plasma spray coatings are vital to the capabilities of jet engines. They allow engines to operate at combustion temperatures that would otherwise melt the superalloy components. Coatings tighten clearance between rotating components, increasing engine compression. They prevent chemical attack and physical erosion. Plasma spray coatings are imperative to the durability and efficient operation of the modern jet engine. In this application coating material property variation has a significant cost. In addition to the variation inherent in the process, some of the biggest contributors to coating property variation have been traced to spray gun nozzle wear and powder feed variation[3, 4]. Presented here are multiple methods utilizing flow induced acoustic signals to quantify noise parameters, measure component wear, diagnose the plasma spray process and detect coating property deviation. Methods have been developed for offline and online analysis of components in addition to online process analysis. These include characterization of nozzle wear by throat roughness measurements and nozzle casting, offline detection of nozzle wear by attenuation of discrete tone generation and broadband signal variation, and offline measurement of powder port wear by jet screech frequency variation. Online methods include pre-ignition nozzle degree of wear measurement by discrete frequency changes; online parameter change detection, process deviation detection with potential source identification, as well as variation in coating property detection by broadband acoustic signal changes. Offline methods allow for 100% accurate new nozzle manufacturer identification. By the same test nozzle wear state can be predicted with over 95% accuracy with the potential for a degree of wear determination. Internal diameter changes of less than 10 microns can similarly be detected. Analysis of online plasma spray acoustic signals as described here can distinguish nozzle state and powder feed variation with over 90% accuracy. The capabilities developed here will aid in plasma spray process variation detection and contribute to identifying the source of this variation. This will improve coating quality and consistency, reduce failures, lower operational costs and ultimately make jet engines more economical, safer, and more fuel efficient with significant environmental and financial cost reduction. / Ph. D.

What would it mean to make space inspired by the sounds of a particular place. The sounds are natural and man-made heard on the site; the place is Virginia Polytechnic Institute and State University's campus. I designed a series of outdoor spaces that reflect sound, and provide a structure where people can add to the sounds of campus. This project creates space that facilitates acoustic activities of a university. The walls reflect and focus sound due to their material and geometry. Sound is treated as a building material; used to help form the spaces that are visibly bounded by concrete and plywood. Concrete walls and plywood floor will alter the acoustic activity on the site; the acoustic fabric will be constantly changing, providing unique moments for people to discover as they pass through the site. / Master of Architecture

High-hostiles exhibit exaggerated physiological responses to stressors as seen by increased cardiovascular reactivity (BP & HR) (Rhodes, Harrison, & Demaree, 2002; Demaree & Harrison, 1997). This exaggerated physiological response style is associated with cardiovascular disease and premature death (Everson et al., 1997). This experiment hypothesized that diminished regulatory control would also be evident in the Acoustic Startle Response (ASR). In this experiment, high- and low-hostile undergraduate men (N = 40) were exposed to a series of startle probes before and after a cold pressor (CP). Startle responses were measured using electromyography (EMG) recorded over the orbicularis occuli. Cardiovascular measures of blood pressure and heart rate were also taken. A 2 X 2 mixed factorial ANOVA was performed with Group (high and low hostile) as the fixed factor, Condition (pre and post CP) as the repeated measure, and peak magnitude EMG (mV) of startle responses as the dependent variable. For startle responses, significant main effects for Group and Condition indicated that high hostiles had larger startle responses than low hostiles and startle responses decreased after the cold pressor (CP). A significant Group X Condition interaction effect was found. Post-hoc analyses revealed no significant group differences before the CP. After the CP, high-hostiles had significantly higher startle responses than-low hostiles. High-hostiles' startle responses did not change significantly after the CP, whereas low-hostiles' startle response magnitude decreased significantly after the CP. Low-hostiles HR increased significantly after the cold pressor and both groups SBP decreased significantly after the cold pressor. / Master of Science

Tactile and visual sound:Experiencing the aural through the use of material and form to direct, create and control sound. / Master of Architecture

Approved for public release; distribution in unlimited. / Optical turbulence plays an important role in the propagation of electromagnetic waves through the atmosphere because it broadens and distorts the optical beam. A variety of optical, thermal, and acoustic instruments are used to detect the atmospheric turbulence and an acoustic echosounder has proven to be a valuable tool to probe the fine dynamic structure of atmospheric turbulence within first hundred meters above the surface. The first planar acoustic echosounder constructed at the Naval Postgraduate School was by Weingartner and Wroblewski, under Walters' supervision. Moxcey later modified this design by reducing the number of drivers from 25 to 19 and placing the drivers closer together into a hexagonal, close-packed array. This thesis explored the potential sources of the transducer ringing and implemented solutions to the problem. Additionally, we also improved the receiving sensitivity of the echosounder and lowered the electronics noise when receiving. Finally, we applied these techniques to another array assembled with new drivers to improve its performance compared to the previous echosounder array, while measuring and quantifying the level of improvement achieved. / Lieutenant Commander, Republic of China Navy

The primary goal of this work is to measure the acoustic properties of a surface in situ. This generally involves sound pressure measurements and a calculation of the acoustic reflection factor of a surface, which may then be used to calculate the acoustic impedance or the acoustic absorption coefficient. These quantities are of use in acoustic simulations, architectural design, room acoustics and problems in noise control. It is of great interest to determine the performance of a particular surface where it is used, as opposed to measurements conducted in a laboratory. In situ measurements are not trivial, caution must be taken to ensure that high signal-to-noise levels are achieved and that the reflections of sound from the measurement environment are taken into consideration. This study presents five measurement methods that may be applied in situ. The acoustic absorption coefficient is calculated for each method on various surfaces spanning the whole range of absorption. Emphasis is placed on frequency resolution, in order to determine absorption characteristics in the bass region (50 Hz to 200 Hz). Advantages and disadvantages of each method are demonstrated and discussed. Finally, the in situ implementation of the surface pressure method is presented and measurements are made in order to test the limitations of this approach.