Scholarship & Research
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Item Freeze foaming: a novel process for the synthesis of foam ceramics(Montana State University - Bozeman, College of Engineering, 2018) Johnson, Nathaniel Peyton; Chairperson, Graduate Committee: Stephen W. SofieFoam is a class of materials that was developed only after World War II and ceramic foams are still in development. Many of the processes for synthesizing ceramic foam require the burning out of a polymer scaffold or the use of chemical reactions to generate pores. This thesis investigates the development of a novel synthesis approach called freeze foaming. In the freeze foaming process, pores are made by putting an aqueous solution under vacuum. The reduced pressure causes the air within the slurry to expand and form bubbles. Then once the foam is formed, it is frozen into place. Then the water is removed from the system through sublimation. Finally, the foam is densified by traditional sintering. After successfully creating ceramic foam samples, the parameters in the freeze foaming process were identified and investigated. Foam samples were characterized by taking density measurements, examining the macrostructure and microstructure with light microscopy, and determining mechanical properties through compression testing. In the end, highly porous foam samples with adjustable properties were synthesized using a novel manufacturing process.Item Theoretical analysis and experimental design of dual-beam optical trap for large particles(Montana State University - Bozeman, College of Letters & Science, 2018) St. John, Demi Rose; Chairperson, Graduate Committee: Wm. Randall BabbittUltra-high sensitivity acceleration and gryometric sensors have been proposed as optically levitated particles in ultra-high vacuum (UHV). Larger particles (10- 30 microns in diameter) provide higher sensitivity, but they are difficult to trap in UHV without particle loss. To overcome the radiometric forces that lead to particle loss, rare earth (RE) ion dopants can be incorporated into the particles to enable solid-state laser cooling of the particles internal temperature. This thesis theoretically and experimentally explores development of optical traps designed for trapping and internally laser cooling large particles. The analysis focuses on dual-beam horizontal traps and the development of code to analyze dual-beam trap potentials and particle loading dynamics. Tolerance analysis, improved particle loader designs, and monitoring and automation of the loading process are investigated. The thesis provides a road map for achieving efficient optical trapping, cooling, and control of large particles.Item Development of a thermal vacuum system for application in space hardware environmental testing(Montana State University - Bozeman, College of Engineering, 2012) Schwendtner, Daniel Thomas; Chairperson, Graduate Committee: M. Ruhul AminSince 2001 the Space Science and Engineering Lab (SSEL) at Montana State University has designed and built a variety of space hardware, as well as developed the facilities necessary for environmental testing of flight hardware. In late 2005, the SSEL began developing a system to simulate the vacuum environment of near-space which would allow for rudimentary outgassing testing as well as thermal testing of electronics and spacecraft components. To truly test hardware and validate hardware analysis and design, the ability to cycle between the expected temperature extremes in a vacuum environment was essential. The usage and operation of thermal vacuum systems was investigated, requirements for a thermal vacuum system were defined, and possible design options were considered. A Finite Element Analysis (FEA) was performed to predict the heat load in Watts on the system when a 40 kg nanosatellite (50 cm x 50 cm x 60 cm) was cycled between -40°C and +80°C at rates of temperature change from 1°C/min to 5°C/min. Additional research, analysis, and design was performed on a thermal shroud surrounding the same nanosatellite and operating under identical conditions. Radiation heat transfer between the satellite on the shroud's inside and the vacuum chamber on the shroud's outside was calculated using the radiation network approach. The LU decomposition method was used to solve the resulting set of simultaneous equations. From the results, a design was selected for the system base plate on which the nanosatellite rested, with the capability of sinking or sourcing 833 W of heat power. Similarly, the thermal shroud was designed to sink or source up to 704 W through the shroud body, and up to 229 W through the shroud top. Testing was performed to validate both the FEA model and the physical hardware. Temperature measurements were taken during system testing to validate the design, and as a means to compare the FEA model of the base plate and the radiation heat transfer calculations with the performance of the system hardware. The results indicated that the system functioned as designed, that it met the design requirements, and that it was capable of completely and safely testing satellites and other space hardware.