Browsing by Subject "shielding"
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Item PET/CT shielding design comparisons(Texas A&M University, 2007-09-17) Coker, Audra LeeThe objective of this project was to compare two different methods of calculating dose through lead-shielded walls in the PET/CT suite at Scott & White Hospital in Temple, Texas. The ultimate goal was to see which of the two methods agreed with the actual physical measurements. Minimizing shielding needed in future suite designs would result in a possible reduction of structural as well as financial burden. Formulas and attenuation coefficients following the basic January 2006 AAPM guidelines were used to calculate unattenuated radiation through existing lead walls. The computer code MCNPX was used to simulate the leaded walls of the PET/CT suite and provide another set of results. These two sets of results were compared to doses gathered from OSL badges placed around the suite for a period of two months. For this type of problem, MCNPX proved to provide results that were inconsistent and unreliable. It was concluded that the traditional computational methods are the most reliable for designing shielding in a PET/CT suite.Item Thermal signature reduction through liquid nitrogen and water injection(Texas A&M University, 2005-02-17) Guarnieri, Jason AntonioThe protection of aircraft against shoulder fired heat seeking missiles is of growing concern in the aviation community. This thesis presents a simple method for shielding the infrared signature of a jet engine from heat seeking missiles. The research efforts investigated two approaches to shield the thermal signature of the Noel Penny Type 401 turbojet at the Texas A&M University Propulsion Lab Test Cell. First, liquid nitrogen was injected through a manifold at a flow rate equivalent to the flow rate of exhaust gases, producing a small temperature reduction in the exhaust but no infrared shielding. Second, water was injected at a flow rate of 13% of the flow of exhaust gases, producing a greater temperature reduction and some shielding. Water was then injected through a manifold at a ?ow rate of 118% of the flow rate of exhaust gases, producing a substantial reduction in temperature and complete shielding of the infrared signature. Additionally, numerical simulations were performed using FLUENT to support these experiments. Results are presented in the form of thermocouple data and thermal images from the experiments, and in the form of temperature contours and streamtraces from the simulations.