京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第19979号 / 工博第4223号 / 新制||工||1653(附属図書館) / 33075 / 京都大学大学院工学研究科都市社会工学専攻 / (主査)教授 藤井 聡, 准教授 SCHMOECKER Jan-Dirk, 准教授 宇野 伸宏 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM

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Modern radar and signal processing applications require data acquisition systems capable of high-speed analog data reception and processing. These systems need to support sophisticated signal processing algorithms and reliable high-speed interfaces. The objective of this project is to develop a prototype of a state of the art data acquisition system to aid NASA’s Surface Water and Ocean Topography (SWOT) mission. The SWOT mission aims at monitoring water levels of various water bodies to predict and avoid any catastrophic events. The principal instrument is a Ka-band Radar Interferometer (KaRIN) that is used for the measurement of water levels. The collected data need to be digitized and processed using an FPGA based-data acquisition system housed in a satellite. The scope of this project involves the design, implementation and test of a high-speed printed circuit board (PCB) that serves as the prototype data acquisition system. A lot of emphasis is placed on layout design, as the PCB needs to support data rates up to three Giga samples per second. The goal of this research is to provide Jet Propulsion Laboratory (JPL), NASA with a prototype version of the high- speed acquisition system that can be integrated with the KaRIN system in future.

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Indiana University-Purdue University Indianapolis (IUPUI) / The purpose of this investigation was to compare the histopathologic effects of kinetic cavity preparation to the histopathologic effects of conventional high-speed handpiece preparation on the human dental pulp. The objective was to test the following hypothesis: kinetic cavity preparation results in significantly fewer pulpal effects than does conventional preparation using the high-speed handpiece. Class V cavity preparations were made in 26 teeth of seven patients who required extraction of these teeth for orthodontic purposes. Thirteen teeth were prepared using kinetic cavity preparation, using 27-um aluminum oxide particles at 160 pounds per square inch pressure. Thirteen were prepared using the high-speed handpiece and 330bur. Glass ionomer restorations were placed in all teeth. Extractions were done 10 to 15days after preparation. On teeth with closed apices, the apical one-third of the root was removed. All teeth were placed in 10 percent formalin solution. Teeth were sectioned and selected slides stained with hematoxylin and eosin for histologic evaluation. Microscopic findings indicated that the amount of remaining dentin was of significant thickness to be protective to the pulp. Pulpal responses ranged from no response in 22 specimens to a mild response in 4 specimens. Based on the results of this study, it was concluded that shallow preparation into the dentin does not cause pulpal damage at 10 to 15 days post-preparation, when using either kinetic cavity preparation or high-speed handpiece preparation. The hypothesis that kinetic cavity preparation causes significantly fewer pulpal effects than does conventional preparation with the high-speed handpiece was rejected.

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This thesis by articles addresses the role played by Chapman-Jouguet (CJ) deflagrations in deflagration to detonation transition (DDT) events. By definition, CJ deflagrations are flames propagating with a sonic flow in the burned gases, and are theoretically the fastest subsonic combustion waves able to propagate steadily, predicted using conservation of mass, momentum and energy. DDT is difficult to describe, as many complex phenomena and their interaction take place, including flame instabilities, turbulent combustion, and combustion in compressible medium, among others. Recent experiments and numerical simulations however showed that, prior to transition to detonations, deflagrations plateau at the CJ regime before rapid acceleration. In the present thesis, multiple aspects of the last stages of DDT are studied, and are each presented in published articles or articles in preparation. The two articles presented in Chapter 2 focus on experiments performed on the transition of a shock-flame complex to a detonation downstream of a single obstacle, in a stoichiometric propane-oxygen mixture at low pressure, mimicking the common configuration found at the last stages of DDT in experiments and numerical simulations performed in a channel filled with obstacles. The relative large size of the obstacle and the low gas initial pressure permitted to visualize the details of the initiation of the detonation around the obstacle. Transition to detonation was found to occur in a similar fashion for variously shaped obstacles, after flame acceleration due to the interaction with reflected shocks. This acceleration process was found to occur rapidly in the case where the incident flame propagated with a burning rate close to the Chapman-Jouguet value. The third article presented in Chapter 3 describes a model aimed to predict the properties of shocks followed by a CJ deflagration, in experimental configurations where the burned gases can be vented. The formulation is similar to the double discontinuity problem adapted from the work of Chue (1993), extended to cases where the burned gases are not confined by a rear wall anymore, but can be vented through an opening of known dimensions. The properties of the shock / CJ-deflagration complex could then be predicted and compared to flame measurements done prior the initiation of detonations, obtained on a selection of large scale DDT experiments. The good agreement suggests that DDT occurs when deflagrations reach the CJ regime, corroborating with observations done in shock tubes. The article presented in Chapter 4 is aimed to present a consistent method for calculating the structure of flames propagating at arbitrary burning velocities, from the low-Mach case (isobaric) up to the CJ deflagration regime. The method uses a dynamical system approach to calculate the steady wave structure, described by ordinary differential equations. A stability analysis near the burned and unburned gases permitted to develop a numerical shooting technique, which was used to obtain the flame structure and burning rate eigenvalue. Chapter 5 is a numerical study of the deflagration to detonation transition problem in one-dimension. By linearly increasing the burning rate eigenvalue to increase the flame burning velocity, the flame first reached the CJ condition. Subsequent increase in the burning rate leads to the self-organization of the flame into a CJ deflagration - shock complex. This self-organization triggers a pulsating gasdynamic instability leading to the transition of the flame to detonation.

Advance warning signals (AWS) provide information warning drivers in advance of the end-of-green phase for an approaching signalized intersection. The purpose of this research was to develop guidelines for the placement of AWS in Utah, both conditions to evaluate the need for AWS installation and guidelines for the AWS system design. The conditions were based on literature of other transportation agencies that had similar AWS systems and were developed using the Policy Delphi method. The Policy Delphi method is the development of a specific policy area through the means of discussion by a committee of experts correlating views and information involving opportunity to react and assess different viewpoints until the committee is in agreement over the policies being recommended. Six conditions are recommended and discussed in detail, including: limited sight distance, posted speed, isolated intersection, high crash rate, approach grade, and heavy vehicle traffic volume. The guidelines for the AWS system design included details about three components: AWS component, advance detection component, and signal timing component. An evaluation matrix was developed by the Policy Delphi method for the purpose of evaluating and prioritizing a group of intersections for AWS installation. A total of 24 intersections were identified by the Utah Department of Transportation for this project that helped to develop and verify the conditions and evaluation matrix. The recommended guidelines and evaluation matrix results are described.