Master of Science

Data on egg delivery routes were obtained from a sample of nine selected Federal-State egg grading stations located in four different areas of Virginia. These data included time and distance requirements, route characteristics and a basis for computing costs. Based upon the time requirements--which included driving time, personal time and time at the stop--and the distance traveled, cost estimates were obtained. Cost comparisons were made by size of plant, size of delivery and type of outlet. Wide variation in delivery costs were found. Delivery costs showed a meaningful decline as volume of delivery increased. Significant differences in delivery costs among different types of market outlets were found. Volume-cost relationships observed indicated that larger volumes of eggs were consistently delivered to certain types of outlets at the smallest unit cost. The marginal cost of delivering selected volumes of eggs specified distances was calculated. / Master of Science

Recently, there has been an expanding interest in the packaging industry concerning thermoplastic film laminations. These types of materials provide a packaging material that can be tailored to the consumers' needs. An understanding of the bonding mechanisms between plastics might prove useful in the improvement or development of film lamination. Infrared spectrometry has been used to study the structures of plastics in the 3.0 - 100 micron region. It was decided that a study of infrared spectrometry in the 1.0 - 3.5 region could provide a tool for studying bonding mechanisms between thermoplastic material. The results of the qualitative study of the structural groups of nine polymers showed that the spectral identification in the 1.0 - 3.5 micron region was possible. These results could provide a means of determining the groups involved in bonding mechanisms. Beer's law has normally been applied to the quantitative analysis of homogeneous gaseous and liquid mixtures. A study shewed that Beer's law was applicable, with limited quantitative accuracy, to solid thermoplastic mixtures. The results indicate that a base-line analysis technique, based on Beer's law can be used to determine concentration gradients. A study of such concentration gradients across the interface of a lamination could indicate the types of bending mechanisms. All samples were analyzed in the form of films with a Beckman DK-2 ratio recording spectrophotometer. An improved method for the preparation of film samples was developed. Thermoplastic resins were pressed between 10 mil Mylar and Teflon FEP films on a Carver laboratory press. / Master of Science

see document / Master of Science

see document / Master of Science

In the assumptions, it was indicated that a modification in the method of analysis would allow taking into account the variation in pressure. This could be done by assuming that the internal pressure P used in the analysis was the pressure after deformation. During deformation, the mass of the enclosed gas remains constant. Thus, knowing the initial and final volumes and the final pressure, the initial internal pressure could be determined using the appropriate gas law. / Master of Science

This thesis presents an investigation and derivation of the expression: fer bending moment, torsional moment, and shear at the ends and at any intermediate point along a circularly curved beam. The investigation includes both cantilever beams and fixed ends beams, loaded with a uniformly distributed load, concentrated loads or a combination of the two. The solutions of the equations have been presented in a graphical form for the case of the uniformly distributed load, and a tabulated form representing the ordinate of the influence lines for the case of the concentrated loads. The graphs and tables cover a series of beams whose arcs are subtending central angles of 50, 45, 60, 75, 90, 120, 135, 150, 165 and 180 degrees and whose stiffness ratio: (K) are 1.33, 2, 4, and 10.67. Special emphasis has been given to reinforced concrete curved beam design as based on the theories and experiments presented in the literature by Timoshenko and Gowan. The investigation shows that many questions still remain to be answered in the design of reinforced concrete beams subjected to bending moment, torsional moment and shear; and there is a need for the ACI Code to give some criteria for such designs in the near future. / Master of Science

The object of this investigation was to develop a general solution for the thermal stresses and strains in a hollow cylindrical case-bonded solid propellant. The heat conduction equation, as solved by Carslaw and Jaeger, was applied to a hollow composite cylinder. The temperature distribution from this equation was used in conjunction with the stress and strain for an elastic solid propellant. The boundary conditions were employed to solve for the constants and the general solution for the stresses and strains were obtained. In order to study the predictions of the general expressions, a numerical example was presented. It was found that the maximum stress and strain appeared at the inner radius of the grain. It was also observed that the stress and strain increased with an increase in the radius ratio "m”. Failure criteria for the grain under consideration were discussed. A method for obtaining the maximum allowable temperature variation (from cure temperature) was investigated. Knowing the stress and strain characteristics of the grain the equations developed would indicate failure conditions and also allow calculations of the maximum allowable temperature variations prior to grain failure. / M.S.

M.S.

A determination of the resonance escape probability of thorium as thorium nitrate in aqueous solution has been made as a function of thorium concentration. The physical system used was an aluminum box surrounded by successive layers of cadmium, paraffin and borated paraffin to keep out neutrons scattered by objects in the laboratory. Neutrons were obtained from a Cockcroft-Walton type accelerator by the D(d,n)He³ reaction. The drive-in target was located at the center of one of the faces of the aluminum box. Neutron density was measured at nine spatial positions in the direction of the neutron beam with a bare boron trifluoride detector. The area under a curve of neutron density versus spatial position was obtained for various concentrations of absorber. The above process was carried out for the thorium solution and for a “mock solution," whose cross-section was similar to that of thorium except that it had no resonances in the thorium resonance region. By taking ratios of the neutron densities (area under curves of neutron density versus spatial position) in the thorium solution to the neutron density in the mock solution, it was possible to determine the resonance escape probability of neutrons in a homogeneous, aqueous solution of thorium nitrate. It is shown that, for the absorber concentrations used in the experiment, the resonance escape probability for an infinite geometry may be obtained by the above ratio method. The difference between a finite system and an infinite one is exhibited as leakage of neutrons from the system in the finite case. If one can compare neutron densities for systems which are large enough so that leakage is negligible or for systems with corresponding leakage rates, the effect of leakage can be overcome and the resonance escape probability for the infinite geometry obtained. Before taking the above ratios of neutron densities, it was necessary to compensate for the spectral shift of the thermal flux in the two solutions. After such a correction, the resonance escape probability so obtained shows good correlation with the results of the Monte Carlo prediction for this system. Over the range covered by the experiment (0 - 1 x 10²¹ atoms of thorium per cubic centimeter), experimental results agree with Monte Carlo predictions to within one percent. Counting statistics were good, with 10⁶ counts normally taken per spatial position. The curves from which the value of neutron density were determined were formed by nine points, each of which represented at least 10⁶ counts. Reproducibility of the neutron density at a point was of the order of one percent. Various changes made in the analysis of the data have caused corresponding changes in the values obtained for the resonance escape probability of less than one percent. These facts all indicate that the uncertainty in the experimental determination is of the order of one percent. Calculations of effective resonance integrals from the experimentally determined values of the resonance escape probability show good agreement with published measurements on other systems. / Ph. D.