The effect of triiodothyronine (L-T₃) on the protein, RNA and DNA fractions of the thymus nuclei of growth-arrested sulfaguanidine-fed rats has been studied. A single dose of 15 µg of L-T₃ stimulated the incorporation of ¹⁴C-labelled amino acids into total nuclear protein, whole histone and histone fractions. The incorporation of the labelled amino acid into nuclear protein was increased 40 percent over the control 4 hours after the administration of L-T₃. The incorporation of alanine-1-¹⁴C into the total histone fraction reached a maximum 4 hours after the administration of L-T₃ and then decreased 8 and 16 hours after the administration of L-T₃. The incorporation of alanine-1-¹⁴C into histone fraction f₁ reached a maximum at 4 hours after the administration of L-T₃ while the incorporation into fractions f_2a, f_2b and f₃ did not reach a maximum until 8 hours after the administration of L-T₃. Time course studies showed that the protein and RNA moieties of thymus chromatin of rats injected with a single dose of L-T₃ was increased to a maximum at 4 hours. The T_m of chromatin was increased 2° by L-T₃ administration as early as 2 hours. However, the T_m of DNA was not affected. Four hours after the administration of L-T₃ the template efficiency increased 171 percent. The template efficiency of DNA was not affected by L-T₃. These results demonstrate that thyroid hormones modify the chromatin in such a way that the template efficiency is increased. An hypothesis for the mechanism of thyroid hormone action was presented. / Ph. D.

Ph. D.

The overall objective of this investigation was to develop a chemical method for treating spent vegetable tannin liquor. Vegetable tannin wastes are plagued by a multitude of undesirable characteristics, principal of which is a color problem. Historically, chemical coagulation processes have been successful in reducing color associated with industrial wastes. The coagulants tested were aluminum sulfate and polyelectrolytes. In addition, the pH and the time interval between aluminum ion and polyelegtrolyte addition were studied. Considerable difficulty was encountered in obtaining a waste product of uniform characteristics over an extended period. This problem was solved by storing a large quantity of waste of typical properties at temperatures near zero degrees centigrade. / Ph. D.

Halphen's Theorem states that, "A necessary and sufficient condition for every dynamical trajectory in a positional field of force in E3 to be planar is that the field of force is either parallel or central." This result has been known for some time, however only the sufficiency part of the theorem is widely documented. A new analytic proof of the necessity part of Halphen's Theorem was developed. The details of this proof motivated the new concepts of a flat point in a field of force and a flat point on a dynamical trajectory in a positional field of force. / Ph. D.

A dynamic pressure measuring system composed of long connecting tube, transducer, D-C amplifier and galvanometer oscillograph were used in a wind study conducted by the Department of Agricultural Engineering, Virginia Polytechnic Institute. The instrumentation was used to measure and record dynamic pressures due to wind velocity. Data recorded in that study indicated velocity head pressure oscillations on some surfaces of the test structure in excess of 100 Hz. This investigation was undertaken to see if the recorded oscillations could have been generated in the measuring system or if they were truly windpressure variations. Components of the pressure measuring system were modeled by transfer functions. From these transfer functions, a system operational transfer function was determined and used to define system frequency response. The frequency analysis indicated the system was severely limited in response by the oscillating air column constrained within the interconnecting tube. The usable frequency range of the system (+ 10% tolerable amplitude error allowable) was found to go from zero to 34.2 Hz. By eliminating the air column this frequency range could have been extended to 99.4 Hz. Phase shifts in these frequency ranges were found to be negligible. Transducers were mounted rigidly to exterior walls of the test structure. The measured fundamental natural frequencies of these walls (transducer mountings) were found to be well within the usable frequency range of the instrumentation; and, therefore, a source of vibration pickup. To improve the measuring system reliability, recommendations were made to eliminate the air column and stiffen the transducer mountings. / Master of Science

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

The subject of this dissertation is the analysis and solution of the equations describing the laminar boundary layer on axisymmetric bodies immersed in an oncoming stream and spinning at a constant rate about their axis of revolution. The flow is allowed to be compressible or incompressible and the geometries for which solutions are obtained include the sphere, cone, paraboloid, hyperboloid and tangent ogive. The only limitation on spin rate involves the assumption that the pressure across the boundary layer remain essentially constant. The method of solution for the set of parabolic nonlinear partial differential equations which describe the boundary layer is an implicit finite difference technique. A study of step size and convergence criteria is included to determine the accuracy of the numerical method. Comparisons with previous approximate methods are also presented in an effort to establish confidence in these results. Boundary layer characteristics in the form of shear stress, heat transfer, velocity and temperature profiles, displacement thickness and frictional drag and moment coefficients are presented for each geometry over a wide range of spin rates. / Ph. D.

This thesis investigates a problem common to many building types--the problem of accommodating audiences gathered for the purpose of viewing an event. It is not an attempt to design a specific facility to accommodate a particular type of event and audience but, instead, an attempt to define criteria applicable to a wide range of spectator seating problems and to establish methods of utilizing these criteria to generate solutions to specific design problems. By definition, a spectator is one who looks on or beholds, especially one witnessing an exhibition. Briefly stated, the problem consists of providing the best fit between the spectators and the spectacle being viewed. The author contends that all of the elements of this problem (spectator, spectacle, and any resultant fit) are easily quantified and hence subject to computer simulation and solution. The primary purpose of this thesis is to investigate the characteristics of spectators and spectacles, establish design criteria based on these investigations, and utilize these criteria to write a computer program capable of generating and evaluating solutions to spectator seating problems. The body of this thesis is divided into three parts. The first (Chapter II, The Spectator) analyzes some physiological characteristics. The second (Chapter III, The Spectacle) investigates the geometrical characteristics of spectacles and their effect on audience configuration. The third (Chapter IV, Computerized Seating Design) describes a computer program which generates and evaluates single-tier seating solutions for arena-type events. / M. Arch.

The main purpose of this study was to review and modify some of the work that has been done concerning the generation of pseudo-random numbers. The PURGE3, MIX1, and MIX2 subroutines, written in FORTRAN IV to be run on the IBM 360 computer system, are used for the generation of pseudo-random numbers from a family of Pearson distributions as well as from any combination of mixtures of two Pearson distributions, a normal distribution with arbitrary mean and variance and a uniform distribution on any finite interval. The primary improvement undertaken here was to increase the efficiency of operation by enabling the PURGE3 and MIX1 subroutines to be called in a single computer program. The Pearson distribution may be specified either by the first four moments or from sample data. The parameters of the fitted distribution are printed and, if desired, the moments and a graph of the distribution of the 100 pseudo-random numbers generated are printed. A graph of the mixture of distributions generated in the MIX1 subroutine may be obtained from 10,000 random numbers generated from the mixture. The MIX2 subroutine functions to generate random numbers only. The speed of generation varies from about 13,000 random numbers per minute for a Pearson distribution which computes and prints the moments from the generated numbers, to approximately 143,000 numbers per minute if mixtures are used without computing the moments from the generated numbers. / Master of Science