Influence of steam-treatment upon properties, structure, and composition of red oak was investigated. Small specimens of red oak heartwood were submitted to steam-treatments at atmospheric pressure for 1.5, 3, 6, 12, 24, 48, and 96 hours. Short steaming induced little or no changes in the properties and the composition of red oak. Prolonged steaming, however, resulted in significant changes in physical and mechanical properties as well as in structure and chemical composition of wood. Shrinkage increased significantly with increasing steaming time. After 96 hrs of steaming volumetric shrinkage to the air-dry condition was 4.4 times that of the non-treated wood and was thus indicative of cell wall collapse. Specific gravity and equilibrium moisture content were decreasing and air-dry density was increasing with an increase in steaming time. Color of wood became darker and the fluid content brighter with prolonged steaming. / Ph. D.

A method of solving the three-dimensional, incompressible turbulent boundary-layer equations was developed using a Crank-Nicholson implicit finite-difference technique, with the turbulent stress terms modeled with an eddy-viscosity model obtained from mixing length theory. The method was applied to two three-dimensional flow geometries for which experimental data exists and a comparison with this data showed excellent agreement. The complete computer program was sufficiently generalized for application to two-dimensional laminar and turbulent flows with arbitrary pressure gradients. The method was applied to several such test cases and the solutions agreed well with both theory and experiment. An analysis was presented to determine the conditions for which the finite difference equations were stable and convergent. The results of this analysis demonstrated that the equations are generally stable and convergent. However, care must be exercised when writing the finite difference approximation to the continuity equation, because certain finite difference formulations of the continuity equation can lead to an instability when the initial values for the distribution of the velocity normal to the bounding surface cannot be accurately specified. / Ph. D.

The purpose of this study was to determine the most accurate method of calculating the most probable producing ability (MPPA) of beef cows based on one, two or three records. A preliminary analysis of preweaning records on 9,515 calves from 4 Angus herds enrolled in the Virginia Beef Cattle Improvement Association program was conducted on average daily gain, 205-day weight and index value. Adjusted 205-day weight was selected for further study. To obtain a realistic repeatability value of adjusted 205-day calf weight, needed for calculating MPPA, separate estimates were first obtained for each herd by intraclass correlation. These values were 0.34, 0.00, 0.35 and 0.14. The individual herd sums of squares and degrees of freedom were then pooled to obtain an overall estimate of 0.31. Repeatability was also calculated by the correlation of adjacent records (r = 0.48) and by the regression of the second record on the first (b = 0.51). The pooled intraclass correlation coefficient (0.31) was selected as the best for the calculation of all MPPAs. MPPAs were calculated by the method of Lush (1949), using the dam's progeny record: (1) as a deviation from the herd-year average, and (2) as a deviation from the sire progeny average within years. MPPAs were calculated by both methods based on each of one, tuo and three records and each of these correlated with the average of all subsequent records (maximum of six). The first, second and third MPPA values by the herd-year method yielded correlation coefficients of 0.18, 0.10 and 0.04 with the average of all subsequent records, respectively. Corresponding sire-year correlation coefficients were 0.23, 0.31 and 0.36, respectively. The differences between the correlation coefficients obtained by the two methods for MPPA one, two and three were significant at the level of P < .10, P < .05 and P < .0005, respectively, indicating that the sire-year method is more accurate. The variance was also lower for the sire-year method (427 ± 44.2 pounds) than for the herd-year method (428 ± 55.2 pounds). Thus, the author has concluded from these results that the sire-year method of calculating most probable producing ability is a more accurate measure of the true productivity of beef cows. / Ph. D.

A spinning apparatus was built for the investigation of the phase-separation technique as applied to the production of polypropylene fibers from naphthalene solutions. The solutions were spun through a single 2.00 millimeter spinneret at compositions of 15 and 22 per cent polymer and at temperatures of 145 and 160°C. Linear velocities in the spinneret and draw ratios ranged from 0.125 to 0.277 meters per minute and from 759 to 2198, respectively. It was found that naphthalene could be extracted from the fibers by diethyl ether in less than one minute; however, this extraction was not necessary prior to properties testing because all of the naphthalene in the fibers exposed to air was lost by sublimation. Deniers of 14 selected fiber samples varied inversely with draw ratio and directly with solution composition in a range from 2.5 to 8.0. After the samples were cold-drawn 3:1, tests with a Scott Tensilgraph showed that tenacities, per cent elongations at break, and secant moduli varied directly with draw ratio in ranges from 0.9 to 1.6 grams per denier, from 50 to 150 per cent, and from 17 to 30 grams per denier, respectively. Per cent elongations at break also varied directly with solution composition. The fibers, in general, exhibited good hand, bulk, tangling, and self-crimping characteristics. Photographs of four of the fiber samples were made to show the tangling and crimp qualities. / Master of Science

The results of the research show that either the EDTA-(NH4)C03 procedure or the multivariate regression equation could be used to estimate the Zn supplying powers of Virginia soils. It was pointed out that the critical levels obtained for the procedures are considered tentative and that the calibration should be continued as more field data become available. / Master of Science

The effect(s) of bromide residues in rat diets on tissue bromide accumulations, organ size, growth rate and physical activity were studied. In Experiment 1, the treatment groups were fed diets containing 290, 600 and 1177 ppm bromide, respectively. The control group received 36 ppm from untreated feed. There were 12 rats on each diet for 56 days. Experiment 2 was divided into 4 groups of 5 rats each, and were fed a diet containing 1177 ppm bromide. Five representative animals were sacrificed every 2 weeks. Weights of the liver, spleen, lungs, heart and testes were recorded for all animals when sacrificed. Tissue samples from these organs and the triceps, gastrocnemius muscle, eyes, abdominal fat, blood and tibia were analyzed by neutron activation analysis (NAA) for bromide residues. A computer program was designed to convert the NAA data to ppm bromide. There was a significant difference in the levels of bromide in the tissues between all treatments in both experiments. The most notable results were the high residual bromide levels found in the eyes (856 ppm) and testes (610 ppm). Bromides were detected in the other tissues in the following levels as ppm: blood (631), liver (304), kidneys (610), tibia (343), spleen (541), triceps (178), gastrocnemius (179), lungs (648), abdominal fat (99) and heart (359). No significant differences in organ sizes, feed efficiency and rate of gain between animals in Experiment 1 or 2 were found. / Master of Science

Female role rejection, defined as a female's expressed disagreement with her ascribed feminine roles was examined. It was hypothesized that female role rejection (dependent variable) is positively correlated with (1) female possession of male traits, (2) a female's desire to pursue a "male" occupation, and (3) a female's perception of "male" occupations as being more prestigious than "female" occupations (independent variables). A scale to measure female role rejection was composed of three components: beliefs about personality traits, housekeeping and childcaring duties, and an occupational dimension. A non sampled population of 284 undergraduate female Sociology students at a large university and a small female college located in Southwest Virginia was chosen. Justification for use of statistical tests was provided by Gold's (1969) contention that statistics can be applied meaningfully to data without regard to sampling considerations. Measurement of possession of male sex traits using one-third of the items on the Mf scale of the MMPI proved unsuccessful and this variable was dropped from the study. The remaining two hypotheses were supported at the .05 level of significance using a one-way analysis of variance and a correlation coefficient with the associated tests of significance. It was concluded that females who desire "male" and "neutral" occupations reject their ascribed roles to a greater extent than females who desire "female" occupations. Also, females who see "male" occupations as being more prestigious than "female" occupations reject their roles more than females who fail to perceive "male" occupations as more prestigious. / M.S.

TOPAZ, which is the Technique for the Optimal Placement of Activities in Zones, was developed to provide the urban planner with a workable tool from which he could determine the best allocation of a set of activities to a set of zones and at the same time minimize cost. The main objective of this research was to determine if TOPAZ could be applied to reservoir recreational planning, and if so, the methodology necessary for its use. An example problem which includes a hypothetical reservoir with six zones and four key recreational activities is posed for the testing of the technique. The four key recreational activities being studied are swimming, picnicking, camping and boating. The model which was developed includes three cost components which are the establishment cost, the road cost and the cost of travel. It is shown that the technique can be a powerful aid to the planner of water based recreational facilities. Not only does the model give the planner a series of near optimal allocations of activities, but by the use of the sensitivity analysis the degree of accuracy to which the data should be collected can be determined, The model is also shown to be useful when applied to non-quantifiable type decisions. The results and a discussion of the results are included along with a discussion of other possible applications of the technique as applied to recreational planning. The planner can refine the model to suit his own particular needs by modifying the data input and the associated constraint set. / Master of Science

Montréal Trigonix inc. 2018

L'analyse des spectres Raman et infrarouges de OF2₂, SCl₂, SO₂F₂ et SO₂CI₂ solides, basée sur la théorie des groupes et les développements récents sur la présence de bandes dues à des modes longitudinaux dans les spectres de vibration de certains cristaux moléculaires, nous a permis de limiter le nombre des structures cristallines possibles de ces composés sur lesquels on ne possédait aucune donnée cristallographique. Même si nous n'avons pas réussi à déduire une structure cristalline unique dans chaque cas, les renseignements obtenus devraient s'avérer précieux lors de la détermination des structures cristallines par des méthodes plus directes, telle la diffraction des rayons X. On peut en effet s'attendre à ce que les travaux en diffraction sur ces solides soient extrêmement ardus, vu les points de fusion assez bas de ces composés. L'analyse des spectres de vibration de OF₂ cristallin a révélé que la maille primitive du cristal contient au moins deux molécules, situées sur des sites de symétrie Cs ou C₁. La présence dans le spectre Raman d'une bande bien distincte due à un mode longitudinal, associé à la vibration transversale v₃, a mis en évidence le caractère piézoélectrique de ce composé en phase solide. Le cristal est donc non-centrosymétrique. De plus, étant donné que la fréquence du mode longitudinal observé ne varie pas pour différents échantillons polycristallins, il est probable que le bifluorure d'oxygène possède une structure cristalline cubique (classe cristalline Td) dont la maille primitive contiendrait 12 molécules situées sur des sites de symétrie Cs . Nous avons aussi étudié les spectres infrarouges de OF₂ isolé dans des matrices solides de néon, d'argon et de krypton, dans des rapports de concentration molaire de 1:1000. Le dédoublement de la bande due au mode v₃ suite à des recuits successifs de ces matrices, nous a amené à conclure que les molécules de soluté se distribuent dans des sites de piégeage différents dans ces matrices. On ne peut cependant définir la nature exacte de ces différents sites. Les spectres infrarouges de SCl₂ gazeux et isolé dans une matrice de krypton, de même qu'un calcul des constantes de force effectué à partir des fréquences des bandes isotopiques de ce composé, ont permis de démontrer que la fréquence du mode de valence antisymétrique (v₃) dans la molécule libre est inférieure à 530 cm-1, contrairement à ce qui avait déjà été publié (535 cm-1). Les spectres de ce composé à l'état solide sont passablement compliqués dans les régions de v₁ et v₃, par suite de l'éclatement des fondamentales par effet de couplage, et de la présence de bandes dues aux diverses espèces isotopiques. En nous basant sur le nombre minimum de bandes observées dans la région des modes de réseau des spectres de vibration, nous avons pu déduire que la maille primitive du cristal contient au moins quatre molécules, situées dans des positions générales. Par ailleurs, ce solide ne saurait être de structure cristalline monoclinique ou triclinique. Le fait qu'aucune bande due à un mode longitudinal n'ait été décelé dans le spectre Raman du solide suggère pour ce composé une structure cristalline centrosymétrique. Contrairement à ce qui avait été avancé en se basant sur l'écart entre les entropies calorimétrique et spectroscopique, les spectres de vibration de SO₂F₂ en phase solide sont caractéristiques d'une structure cristalline bien ordonnée. Les épaulements longitudinaux observés du côté des hautes fréquences de plusieurs des fondamentales dans le spectre Raman prouvent sans ambiguité que le cristal est non-centrosymétrique. L'analyse de ces spectres nous a permis de déduire que la maille primitive du cristal contient au moins deux molécules, situées sur des sites de symétrie ou Cs ou C₁. De plus, la structure cristalline de SO₂F₂ ne saurait être triclinique, trigonale ou monoclinique si les molécules sont situées sur des sites de symétrie Cs . Le nombre de modes de réseau distincts (12 au total), observés dans les spectres Raman et infrarouge de SO₂C1₂ cristallin, indique que le cristal contient au moins 4 molécules par maille primitive. Les dédoublements de la bande due au mode de torsion v₅ (A₂) dans le spectre de diffusion, et de celles dues aux modes de symétrie A₁ dans le spectre d'absorption, prouvent que les molécules dans le cristal ne sont pas situées sur des sites de symétrie ou C₂v ou C₂. De plus, le grand nombre de bandes observées dans les régions de v₁ et v₄ du spectre Raman s'explique mal par une symétrie de site Cs. La présence d'épaulements longitudinaux dans le spectre Raman du solide prouve que la structure du cristal est non-centrosymétrique et suggère qu'elle n'est pas cubique. Il est probable que les molécules se situent dans des positions générales de la maille élémentaire du cristal, qui peut appartenir aux systèmes orthorhombique, tétragonal (quadratique) et hexagonal. / Montréal Trigonix inc. 2018