For direct reentry from a lunar or deep space mission, considerable variation in reentry plane, reentry point, and reentry angle must be anticipated. The returning vehicle must therefore, possess the ability to control its range after reentry in order to touch down in the desired recovery area. Recent studies have indicated that considerable ranging capability is available with even low lift-drag ratio vehicles operating wholly within the atmosphere if aerodynamic maneuvering is initiated while the vehicle still possesses greater than satellite velocity. In these studies, maneuvering was initiated shortly after the initial pull-up. Range control is also available during the initial pull-up, but such control results in little gain in longitudinal ranging capability in most cases. It is the purpose of the present thesis to investigate the feasibility of increasing lateral ranging capability by banking during the initial pull-up. Low lift-drag ratio vehicles reentering the atmosphere in a banked attitude are considered and the effects of such reentries on allowable corridor width, and lateral range capability are studied. Equations are developed for the motion of a vehicle reentering the atmosphere of a spherical, non-rotating earth, and some permissible approximations applicable for the present problems are discussed. Numerical results obtained for the developed system of equations through use of an IBM 7090 high-speed computer are used throughout the investigation to furnish accurate evaluations of the effects being studied and to check the validity of some of the approximations used. Particular emphasis is placed on reentry at escape velocity, but the effects determined apply in character to reentry at other supercircular velocities. / Master of Science

It was the intent of this investigation to determine boiling film coefficients of SO₂ in a temperature range not previously investigated. Further, a practical method of circulating liquid SO₂ and reclaiming SO₂ vapor without a compressor or pump was attained. For the range investigated the boiling film coefficients decreased with an increase in temperature difference between the boiIing SO₂ liquid and the surface of the heater. This occurred in the regime of partial nucleate boiling. Favorable comparisons were made with the limited information available for this bolling regime. It was found that the controlling film coefficient was on the steam side of the test evaporator. This was due to the comparatively large values obtained for SO₂ bolling film coefficients. Within the limits of this investigation, the overall heat transfer coefficient may be taken as approximately equal to the steam film coefficient. Much more work needs to be done in the regime of partial nucleate boiling as the available literature is far from complete. / Master of Science

M.S.

The thesis develops the acoustic theory of the propagation of the shook waves produced by an aircraft in supersonic flight through an atmosphere in which the speed of sound decreases linearly with altitude. The problem is first studied in terms of the geometry of the rays along which the shock wave travels away from its point of origin and into the surrounding atmosphere. The equation of the rays is derived and certain important properties of the rays are discussed. It is shown how these results lead to a systematic graphical procedure for determining the location of the shock wave of a maneuvering aircraft. The theory is then considered in terms of the geometry of the "wave fronts" which represent the instantaneous positions of the individual disturbances created along the flight path. The shape of a wave front and its growth with time are determined. From this the equations for the envelope of a one-parameter family of wave fronts are obtained. The envelope equations are solved in parametric form and several examples are worked out which show some effects of flight maneuvers upon shock wave propagation. / M.S.

M.S.

Propionyl carboxylase purified from bovine liver mitochondria catalyzes the carboxylation of 992 micromoles of propionyl-CoA per hour per milligram of protein. Relative carboxylation rates for acetyl-, propionyl-, butyryl-, and valeryl-CoA remain constant during purification. The carboxylase is inhibited by PCMB, N-ethylmaleimide, and iodoacetamide; and the inhibition by PCMB can be almost completely reversed by GSH. The K_m values for acetyl-CoA, propionyl-CoA, butyryl-CoA, valeryh-CoA, propionyl pantetheine, ATP, and HCOj were determined. The K_m values for the aeyl-CoA derivatives are approximately the same while there is a 200-fold difference between the V_m values for propionyl-CoA and valeryl-CoA. Coenzyme A and valeryl-CoA, but not propionyl pantetheine were found to be competitive inhibitors of propionyl carboxylase. The apparent equilibrium constant for the enzymatic propionyl-CoA carboxylation reaction at pH 8.15 and 37°c is 8.1 x 10^-3 and the Δ F°₃₁₀ calculated from this constant is 2970 calories per mole. / Master of Science

An examination of a proposed state self-insurance fund to replace commercial fire insurance on public properties. / Master of Science

Very few sewage and industrial waste treatment effluents are free from microorganisms and proteins. Such discharges require further treatment by the receiving stream and consequently lower stream quality. The object of this investigation was to evaluate chlorinated solvent processes for the removal of microorganisms, proteins, and other substances from sewage and other wastes. Six different chlorinated solvents were added to different waste samples in the ratio (by volume) of five percent solvent and 95 percent waste, mixed and allowed to settle for a specified period of time. The efficiency of the solvent extraction process was evaluated in terms of reduction of suspended solids, biochemical oxygen demand, and by increased weight of residue separable by sedimentation. The results showed that the process produced the following effects on settled sewage. Suspended solids were reduced by 85 percent, the weight of residue separable by sedimentation was increased 33 percent, and the biochemical oxygen demand was reduced 49 percent. The process was less effective for the treatment of raw sewage, trickling filter effluent, sewage lagoon effluent, or for separation of activated sludge. The variables investigated were temperature, pH and the solvent waste system. Temperature and pH appeared to have negligible effects on the extraction efficiency. The solvents employed were; chloroform, ethylene dichloride, chlorobenzene, carbon tetrachloride, trichloroethane, and dichloroisopropyl ether. Solvents with low vapor pressures and wastes with low concentrations of suspended solids appeared to be the most efficient system. The addition of 20 percent of butanol (by weight) to trichloroethane appeared to increase the extraction efficiency of trichloroethane. Bacterial counts made indicated that the solvent extraction process was affecting better than 90 percent removal of microorganisms from the waste samples. More research will be needed to completely evaluate chlorinated solvent processes for the removal of microorganisms, proteins, and other substances from sewage and other wastes. / Master of Science

The design of a practical torque sensing governor which can be used with any type of prime mover and load was accomplished. An investigation was performed to determine the advantages of such a governor as applied to a small internal combustion engine. The characteristics of the engine, torque sensor, and load were determined in order that the system composed of the aforementioned elements could be simulated on an analog computer. The simulated system was governed by a simulated torque sensing governor and optimized, then the same procedure was followed with a simulated proportional-integral-derivative governor. The real system was then governed by each type of governor using the optimum values of governor parameters obtained from the simulated system. The control response curves of the real and simulated systems using both governors were obtained by application of a step-change in load. From these response curves it was determined that for both the real and simulated systems the torque sensing governor produced less speed error for less time than the proportional-integral-derivative governor. Open-loop frequency response data were taken for the real system using each governor and the Nyquist stability criteria applied. The Nyquist criteria showed the system to be stable when either governor was used. The Nyquist plots showed that the torque sensor reduced phase lag more than the derivative component of conventional control. / Master of Science

This thesis is an investigation of the effect of welding heat on the properties of hardened concrete. In precast concrete structures, where the bearing plates are embedded in the concrete, the welding heat on these plates, generated by the electric arc, penetrates into the concrete. It has been known for many years that high temperatures will lower the modulus of elasticity and the ultimate strength. This thesis is concerned with the “critical” temperatures at which losses begin and the arc energy required to develop this temperature at a reasonable depth into the concrete. In the investigation, the “critical” temperature, using limestone aggregate concrete that might be typical for precast construction, was found to be between 900°F and 1,000°F. The investigation, to determine the arc energy required to develop this temperature, was halted when under severe heating, where the arc burned through both plates, the maximum temperature at a point one half inch from the bearing plate was 710°F. Although cracking was severe in the immediate vicinity of the plate, the moduli of elasticity were lowered only slightly and the welding heat was not high enough to affect the ultimate strength. / Master of Science