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Novel Concepts For Enhanced Nuclear Thermal Propulsion Using Flow Area Tailoring And A Grooved-Ring Core Design, Julien Michel Apeloig Jan 2007

Novel Concepts For Enhanced Nuclear Thermal Propulsion Using Flow Area Tailoring And A Grooved-Ring Core Design, Julien Michel Apeloig

Theses and Dissertations

The most likely candidate for human missions to Mars and beyond will be spacecraft using Nuclear Thermal Propulsion (NTP). NTP provides for high thrust-to-weight ratio and significantly improved specific impulse over even the best chemical rockets. The improved specific impulse reduces required trip times, thereby minimizing the exposure time of the crew to space radiation. Using the PHOEBUS 2A 5 GW reactor, developed in the 1960’s with a thrust of 1,113 N and a specific impulse of 820 s, as a basis for comparison this thesis focuses on efforts to improve the specific impulse and reactor longevity. Hydrogen is the …


Design Study Of Triggered Isomer Heat Exchanger-Combustion Hybrid Jet Engine For High Altitude Flight, Christopher E. Hamilton Mar 2002

Design Study Of Triggered Isomer Heat Exchanger-Combustion Hybrid Jet Engine For High Altitude Flight, Christopher E. Hamilton

Theses and Dissertations

This study investigated the possibility of utilizing a Triggered Isomer Heat Exchanger (TIHE) within a conventional jet engine in order to increase the endurance of a High Altitude Long Endurance (HALE) Intelligence, Surveillance, and Reconnaissance (ISR) aircraft. Optimizations of the conventional and TIHE engines along with selection of a switchover flight condition, where the aircraft switches from combustion to TIHE operations, were made utilizing engine design and mission analysis software. Radiation shield weights were determined utilizing point source gamma ray shielding methods. The jet engine best suited for the hybrid use, where both combustion and TIHE components located in a …


A Transmission Electron Microscopy Study Of Some High Strength Plain Carbon Steels, George Joseph Vytanovych Jan 1967

A Transmission Electron Microscopy Study Of Some High Strength Plain Carbon Steels, George Joseph Vytanovych

Masters Theses

"Methods of preparing foils of high strength, heat treated, plain carbon steels for examination in the electron microscope by the transmission technique were perfected and are described. Two processes for the initial thinning of a bulk sample were successful. A chemical process was found to be more rapid but not satisfactory for small samples. A mechanical process was slower, but was applicable to the smaller specimens. Electro-polishing the thinned material yielded acceptable foils from which photomicrographs of good quality were obtained. The microstructure of the high strength steel samples showed typical tempered martensite. No reasons for the differences in ductility …