No description available.

M. S.

No description available.

no abstract provided by author / Master of Science

This investigation was undertaken to determine the feasibility of producing a cellular, lightweight product by subjecting shales to temperatures of 2100 ± 100 °F in a muffle furnace. Such a product can be utilized as an aggregate for lightweight concrete to supplement cinders which have long been used. The growing scarcity of cinders and the inferior quality of the cinders now available account for the demand for another material to replace them. Samples of weathered and non-weathered, Liberty Hall shale; non-weathered, Martinsburg shale; weathered and non-weathered, MacCrady shale; and non-weathered, Brillier shale were obtained from deposits located in the state of Virginia. The degree of bloating or expansion of the shales was measured by determining the bulk density of the shale before and after exposure to 2100 ± 100 °F. The best bloating shale investigated, non-weathered Liberty Hall, bloated from a bulk density of 2.349 to 0.544 gram. per cubic centimeter; while the poorest bloating shale, Brallier, bloated from 2.448 to 2.389 grams per cubic centimeter. In a firing test on tour types of whale, weathered and non-weathered Liberty Hall and non-weathered Martinsburg and Brallier, it was determined that only 12.5 percent of the total bloating occurred in the temperature range between 70 and 1900 °F, while 87.5 percent occurred in the temperature range from 1900 to 2200 °F. In firing tests using non-weathered Liberty Hall shale it vu found that no additional bloating occurred after prolonged heating at 2050 °F for forty-five minutes. This was indicated by no change in the bulk densities of the fired and unfired test specimens. Additional firing tests using specimens of non-weathered Liberty Hall. shale indicated that a rapid firing schedule was conductive to good bloating. The specimens showed bulk densities of 0.524 and 0.623 gram per cubic centimeter when heated to 2050 °F in twenty minutes and one hour and forty-five minutes, respectively. Weathered and non-weathered MacCrady shale showed no bloating tendencies at the temperatures used. in this investigation. The densities of cinder concrete and bloating shale concrete were 93.47 and 114.3 pounds per cubic foot, respectively. The densities of these materials compare favorably with ordinary sand and gravel concrete which weighs approximately 145 pounds per cubic foot. / Master of Science

The purpose of this thesis has been to investigate the influence of secondary effects for beams resting on elastic foundations and vibrating beams. Two problems have been presented for beams on elastic foundations and a general comparison has been made for an infinite vibrating beam. / Master of Science

Molecular or short-path distillation is one form of high vacuum distillation, and offers a means of separating heat-sensitive, high-boiling materials which cannot be separated by conventional methods. Many of the so-called "undistillables," which include the natural fats and waxes, sugar derivatives, petroleum residues, plasticizers, dyes, and a host of other substances now fall within the scope of molecular distillation. The use or the process is limited, however, due to the high costs involved and the poor separatoey powers which are still characteristic of this method or distillation. Although there have been many mechanical improvements in the constructional designs of the molecular stills since the early beginnings of the crude pot stills, they still remain too inflexible in design and too compact in construction to allow the proper study or the fundamental factors affecting their performance. One of the problems yet to be solved satisfactorily is the prevention of leaks through the bearings and packings of the rotor shaft. It was the purpose of this investigation to redesign and reconstruct a five-inch magnetically-driven centrifugal molecular still, and by so doing to eliminate leaks around the rotor shaft by enclosing the rotor within the still head, and to gain flexibility by the use of a high-form bell jar, and a water-cooled condenser. The still head assembly consisted of a number of integrated units, many of which were of the same design and construction as the units used in other stills by previous investigators. Some of the more important changes were; a magnetic drive, consisting or an inner flange of magnets connected to the rotor shaft, and an outer flange of magnets connected to the drive shaft of the motor, a nitralloy rotary gear feed pump, especially fitted and constructed as a vacuum tight unit, and a water-cooled copper condenser, so constructed that its distance from the rotor surface could be varied. The feed, residue, and distillate tanks, as well as all flow lines for the feed, were constructed of aluminum or aluminum tubing; the vacuum lines were constructed of copper tubing, and all joints on the vacuum lines were either bronzed or silver-soldered to minimize the possibilities of leaks. All other constructional features of the still, such as electrical connections, vacuum connections to the base plate, bell jar seal, and thermocouple construction, were the same as used by previous investigators. / Master of Science

The classical method, required for its solution, the application of boundary conditions to the solution of the beam equation. Except for the case cf the beam with one concentrated load at the center, it was not considered a practical solution. The transcendental equation obtained in the solution of the unsymmetrical case, considered in part B, was found too cumbersome to handle. It was not attempted in parts C and D. The Rayleigh Method proved to be a simple, accurate and reasonably rapid method for all cases considered. The Dunkerley Equation gave very satisfactory results for parts A, B, and C. It was rapid to use, accurate and in most cases the data could be found in prepared tabulations. Results were inaccurate for the two span beam, indicating the necessity for caution in its application to multi-span beams. The Ritz Method, which is a refinement of the Rayleigh Method, proved to be exceedingly accurate when applied to the beam with the single concentrated load. However, it was found, that as the number of terms in the assumed deflection equation increased, the work became more time consuming. It was used only in parts A and B. The Influence Coefficient Method and the application of D'Alembert's Principle, which methods are quite similar, proved to be simple, accurate, and rapid. However, as the number of degrees of freedom increased, the degree of the algebraic equation increased, which complicated the solution. The Iteration Method is probably the method to be used if the number of degrees of freedom exceeds three. As the number of modes increases the number of iterations would increase, but the individual operations in themselves would remain simple. This method proved simple and accurate to use. For the cases considered, it was more time consuming to use than either the Influence Coefficient Method or the application of D'Alembert's Principle. However, for higher degree situations, it should prove to be a more practical method. / Master of Science

This investigation of design factors and operational requirements for irrigating burley tobacco was conducted on a system of irrigation control plots located on the Smithfield farm of the Virginia Agricultural Experiment Station. / Master of Science

A method has been proposed for obtaining confidence intervals for the differences between treatment means in an analysis of variance. The intervals have the following properties: (1) The probability that the interval will cover the parameter is greater than or equal to (1 - α), and (2) If the same procedure is applied simultaneously to each of the pO2 differences among p means, the probability that all confidence intervals will cover the parameters correctly is at least (1 - α) ^{p - 1}. The same properties hold if the procedure is simultaneously applied to special linear comparisons among the means as well as to differences between single means. The intervals are complex in that the limits are dependent on the values of nuisance parameters. Three alternatives for handling these nuisance parameters are discussed, and one is preferred for use in practice. / Master of Science