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No description available.

Hydrocarbon exploration, global navigation satellite systems, computed tomography, and aircraft avionics are just a few examples of applications that require system operation at an ambient temperature, pressure, or radiation level outside the range covered by military specifications. The electronics employed in these applications are known as "extreme environment electronics." On account of the increased cost resulting from both process modifications and the use of exotic substrate materials, only a handful of semiconductor foundries have specialized in the production of extreme environment electronics. Protection of these electronic systems in an extreme environment may be attained by encapsulating sensitive circuits in a controlled environment, which provides isolation from the hostile ambient, often at a significant cost and performance penalty. In a significant departure from this traditional approach, system designers have begun to use commercial off-the-shelf technology platforms with built in mitigation techniques for extreme environment applications. Such an approach simultaneously leverages the state of the art in technology performance with significant savings in project cost. Silicon-germanium is one such commercial technology platform that demonstrates potential for deployment into extreme environment applications as a result of its excellent performance at cryogenic temperatures, remarkable tolerance to radiation-induced degradation, and monolithic integration with silicon-based manufacturing. In this dissertation the radiation response of silicon-germanium technology is investigated, and novel transistor-level layout-based techniques are implemented to improve the radiation tolerance of HBT digital logic.

Structure-property quantification of an A36 steel alloy was the focus of this study in order to calibrate and validate a plasticity-damage model. The microstructural parameters included grain size, particle size, particle number density, particle nearest neighbor distances, and percent of ferrite and pearlite. The mechanical property data focused on stress-strain behavior under different applied strain rates (0.001/s, 0.1/s, and 1000/s), different temperatures (293 K and 573 K), and different stress states (compression, tension, and torsion). Notch tension tests were also conducted to validate the plasticity-damage model. Also, failure of an A36 I-beam was examined in cyclic loads, and the crack growth rates were quantified in terms of fatigue striation data. Dynamic strain aging was observed in the stress-strain behavior giving rise to an important point that there exists a critical temperature for such behavior.

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Dynamic testing provides valuable insight into the behavior of materials undergoing fast deformation. During Split-Hopkinson Pressure Bar testing, stress waves are measured using strain gauges as voltage variations that are usually very small. Therefore, an amplifier is required to amplify the data and analyze it. One of the few available amplifiers designed for this purpose is provided by Vishay Micro-Measurements which limits the user’s options when it comes to research or industry. Among the challenges of implementing the Hopkinson technology in the industry are the size and cost of the amplifier. In this work, we propose a novel design of a signal conditioning amplifier that provides the following functionalities: voltage excitation for strain gauges, wide gain range (1-1000), signal balancing, shunting, and filtering. The main objective is to make a smaller and cheaper amplifier that provides equivalent or better performance allowing larger application of the Hopkinson technology in the industry.