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Available space for a totally implantable cardiac prosthesis. Progress report, April 1, 1973--July 31, 1973

Description: The goal of the present program is to define the spatial constraints of the body for a totally implantable radioisotope-powered cardiac prosthesis. The design is such that the prosthesis is compatib1e with both the human and the experimental animal, the calf. Most recent efforts were directed to the definition of the size and shape of the human thorax for implanting the blood pump. This was done by formulating a mathematical shape model from dimensions obtained from plastic molds made in the chest cavity of human cadavers. The shape model was used in conjunction with dimensions obtained from 100 chest radiographs of living humans to arrive at a statistical distribution of chest dimensions. The results are presented as scale drawings of the walls of the thorax as a iunction of the percent of the population having sizes smaller than the given curves. An effort is underway to define the natural heart boundaries in the chest to define soft tissue and vascular connections in the thorax. A parallel effort was to determine the anatomical and physiological tolerance of calves to implanted models of the thermal conventer. Five calves were implanted with models, four have been sacrificed at 8 to 12 months after implantation, and one remains under observation. All calves were in good physical condition with the retroperitoneal infrarenal space appearing to be most feasible for implantation. (auth)
Date: January 1, 1973
Creator: Nose, Y.
Partner: UNT Libraries Government Documents Department

Biomedical engineering support. Quarterly progress report, October 15, 1972--February 15, 1973

Description: During the quarter covered (October 15, 1972 to February 15, 1973), additional models of the nuclear engine were implanted in calves to evaluate the chronic effects of weight and size. Further characterization of the bench test heart pump was performed, The effect of pump rate on cardiac output was evaluated. The effect of outflow (anterial) pressure on cardiac output was evaluated. Bjork- Shiley valves with stainless steel disks and pyrolitic carbon disks were tested and the effect of cardiac output evaluated. A design of a quick connect system to enable rapid connection of the atrial cuffs and anterial graphs to the blood pump was undertaken. Molds of the implantable version of the ventricles were completed, and construction techniques and evaluation of the ventricles is now in progress. A protocol for the implantation of the pump mechanism into calves for testing is under consideration. (auth)
Date: February 15, 1973
Creator: Kolff, W.J.
Partner: UNT Libraries Government Documents Department

Mound Laboratory isotopic power fuels programs: July--September 1973

Description: Progress in the isotopes fuel program during July to Oct 1973 is reported. Preparation and fuel characterization studies of /sup 238/Pu fuels continued. The effect of lower pressing temperatures on pressed plutonium oxide (PPO) spheres was evaluated. Plutonium-238 dioxide feed material that was sintered to a maximum of only 900 deg C was pressed under otherwise normal conditions into a Multihundred Watt (MHW) type fuel sphere. This pressing resulted in a sphere with near-perfect surface texture. The surface was bright and totally free of any visible cracks. However, upon subjection to the normal 1500 deg C vacuum heat treatment, the sphere cracked severely. Metallographic examination of selected areas of MHLV- PPO spheres showed that the spheres were not uniform in microstructure. They possessed nonuniform grain size and porosity distribution. Spheres exposed to high-temperature heat treatments also were nonuniform in microstructure. Calculations were performed to determine the stresses that appear in MRW PPO spheres due to temperature gradients. Thermal shock analyses were also performed. The data obtained as a result of these analyses were used in establishing a controlled heating and cooling cycle for the 1500 deg C, 1-h outgassirg process for development and production spheres. In order to evaluate the performance of a quadrupole mass spectrometer capable of evolved gas analysis of PuO/sub 2/ up to 1850 deg C, a residual gas analysis system utilizing a quadrupole mass spectrometer was installed in an alpha glovebox. The installation and cold check-out of the system are essentially completed. Several nonradioactive samples and standands were analyzed to establish the sensitivity and to calibrate the instrument. Samples of iridium hemishells were examined using the quadrupole mass spectrometer and both transmission and scanning electron microscopy. These examinations were performed in an attempt to better identify the nature of the iridium being used in the Multihundred ...
Date: November 21, 1973
Partner: UNT Libraries Government Documents Department

SNAP 8 summary report

Description: The SNAP 8 Program was directed toward the development of lightweight nuclear reactors which would operate in space for greater than 10,000 hr at a power level of 600 kW(t). Toward this objective, two reactors were designed, built, and successfully operated. The experimental reactor (S8ER) was an engineering test of a prototype core, but did not have flight-developed hardware. The developmental reactor (S8DR) was a nuclear system test to verify the operability of the integrated flight configuration. The development, design characteristics, operating experience, experimental results, and supporting tests for the S8ER and S8DR are discussed. 20 references. (auth)
Date: September 24, 1973
Partner: UNT Libraries Government Documents Department