Aspartate transcarbamylase (carbamoyl phosphate: Laspartate carbamoyltransferase, E.C. 2.1.3.2.) activity from a thermophilic strain 7-11-05 of Chlorella pyrenoidosa appears to be stabilized during and after (NH₄)₂SO₄ precipitation of the enzyme by at least two factors, one having a molecular weight greater than 10,000 and the other having a molecular weight less than 10,000. The high molecular weight factor(s) appears to be an albumin-like protein which is important in stabilizing the activity of the reconstituted enzyme during storage in buffer. The low molecular weight factor(s) is necessary for stabilization of enzyme activity both during and after (NH₄)₂SO₄ precipitation, and it appears to be organic in nature. Stabilization of enzyme activity in whole son1cates during aging appears to be dependent on a heat-stable factor(s) which has a molecular weight of less than 1,000. Aspartate transcarbamylase activity can be stabilized and modulated in vitro by a number of different compounds such as carbamoyl phosphate, UMP, uridine, and cytidine. This low molecular weight stabilizing factor(s) is suggested to be similar to the low molecular weight factor(s) necessary for stabilization of the enzyme during and after (NH₄)₂SO₄ precipitation. The decay of enzyme activity during aging in vitro is proposed to be due to a breakdown of a polymeric form of aspartate transcarbamylase into subunits which have greater catalytic activity than the native enzyme and which are labile 1n the absence of a stabilizing factor(s). An active breakdown of a stabilizing factor(s) could not be observed in whole sonicates, and proof of an active breakdown of the enzyme itself must await further experimentation. / Master of Science

The influence of DMSO (dimethyl sulfoxide) on foliar absorption and translocation of herbicides and plant membrane permeability was investigated. Primary leaves of bean (<i>Phaseolus vulgaris</i> L., var. Black Valentine) were treated with ¹⁴C-labeled DMSO, 3,6-dicholoro-<u>o</u>-anisic acid (dicamba), 1,1′-dimethyl-4,4′-bipyridinium salt (paraquat) and 2-choloro-4(ethylamino)-6-(isopropylamino)-<u>s</u>-triazine (atrazine). DMSO at concentrations of 25% or more caused by varying degrees of acute toxicity. However, ¹⁴C was generally distributed throughout the plant 5 days after application of DMSO-¹⁴C, as determined by autoradiography and counting. DMSO, 30%, was not as effective as 0.25% Tween 80 (non-ionic surfactant containing polyoxyethylene sorbitan monooleate) in enhancing the absorption and translocation of dicamba, a phloem-mobile herbicide. Tween 80 was more effective than DMSO in enhancing the foliar uptake of atrazine and distributing it within the treated leaves. The contact toxicity and apoplastic movement of paraquat was increased with DMSO. Spectrophotometric studies revealed the absorption spectrum of paraquat was shifted by addition of DMSO. Root uptake of KH₂³²PO₄ by corn (<i>Zea mays</i> L., var. VPI 646) was inhibited by 3% or higher DMSO. Treatments of DMSO reduced oxygen uptake in corn roots. DMSO failed to increase diffusion of labeled solutes through isolated plant cuticular membranes. In <i>Beta vulgaris</i> L. (beet) permeability studies, DMSO increased efflux of betanin from root cells. Combining atrazine with DMSO resulted in a greater increase in membrane permeability. Membrane permeability of corn mitochondria as determined by characteristic swelling and shrinkage was unaffected by DMSO. / M.S.

This is an exploratory thesis. The objective of this thesis is to isolate human measurement error in a physical measuring environment. A secondary objective is to evaluate this measurement error, if successfully isolated, with respect to its effect of biasing statistical quality control tests that describe a manufacturing process. The author of this report designed a specialized measurement jig that was used to isolate human measurement error. Specifically, the tests involved seven human inspectors making micrometer measurements of the diameters of cylindrical brass pieces. Several physical factors were rigidly held in control or eliminated by the design of the jig and the experimental process. This was necessary to obtain as accurate an estimate as possible of the human error. The human measurement error in this experiment was successfully isolated. Further analysis of this measurement error led to the hypothesis that it probably can bias statistical quality control tests that describe a manufacturing process. This bias is reasoned to have a greater effect on statistics that describe processes with very close physical tolerances. / Master of Science

Using Richard Krutchkoff and Stephen Custer's stochastic model for pollution in estuaries, a Stochastic Simulation study of random inputs of pollution particles in estuaries was made. This study investigated four types of input in each of twelve estuarial situations and examined the resulting average distributions of both the biochemical . oxygen demand and the oxygen deficit. For two types of input, the number of input particles ranged from zero to ten and was chosen randomly from a binomial distribution and a uniform distribution. Another type of entry used an input of zero or ten particles, each with probability of .5. These three situations were compared with a constant input of five particles, which was the mean number of input particles for each of the probability-input cases. Graphs were plotted using all four types of input for each estuarial situation. On the basis of these graphs, the study indicates that the average distributions of both pollution particles and oxygen deficit particles which result from using random inputs do not differ significantly from each other and from the average distributions obtained by using the mean input. / Master of Science

Previous discrete analysis techniques applied to shear walls with openings have utilized finite elements with linear displacement fields. These elements require relatively fine meshes in order to correctly describe the reverse bending behavior of the connecting beams and to avoid an idealization for the shear wall which is too stiff. This study presents the use of finite elements which have additional degrees of freedom and allow curved deformation patterns to exist. These refined elements are also combined with plane frame beam elements which are used to idealize slender connecting beams in pierced shear walls. This combination of elements is also applied to analysis of the interaction of shear walls with their surrounding frames in plane frame shear wall combinations. A computer program is developed and presented which is capable of handling a wide range of general shear wall configurations. Only the geometry, loading conditions, and elastic properties are used as input to the program. The output consists of the input data, as a check, then the displacements and stresses at each node as well as member and actions for the beam elements if they are used. Several refined finite element solutions are compared with experimental results for pierced shear wall problems of varying story heights and beam to shear wall stiffness ratios as well as frame and shear wall configurations. These comparisons provide initial guidelines for the efficient use of this refined element in the analysis of general shear wall configurations. / Master of Science

The purpose of this investigation was to design, build, and test a preparative-scale column which contained a blocked-off center tube, thus forming an annular space for the packing. The chromatographic system for this study consisted of 1-methylnaphthalene injections with helium carrier gas and a liquid phase of Craig polyester succinate on crushed firebrick. The analytical column had an inside diameter of 0.061 inches. For the preparative-scale column, the outer diameter was. 2.075 inches and the inside diameter was 1.050 inches. The operating temperature for both columns was 300 degrees Fahrenheit. The flow rates were 0.012 and 10.30 liters per minute for the analytical and preparative-scale columns, respectively. Several sample sizes were injected on both columns. Variation of HETP with sample size was determined. Preparative-scale column efficiencies were calculated from average HETP's at all sample sizes tested. Efficiencies of 36.5, 33.4, 58.2, 69.3, and 52.7 per cent relative to the analytical column were calculated for preparative-scale injections of 0.1, 0.3, 0.5, 0.7, and 0.9, milliliters, respectively. HETP for the preparative-scale column was very sensitive to variation in sample size in the range from 0.l to 0.9 milliliters. HETP for the analytical column was not sensitive to variation in sample size in the range from 0.12 to l.00 microliters, as was expected from literature data. / Master of Science

James Breckinridge, frontier aristocrat, was active in the Virginia House of Delegates during the formation of the United States under the new Constitution. He was a member of Congress from 1809-1817, a time when the young nation was beginning to stand on its own and develop internally and internationally. Bearing the Federalist label, Breckinridge' s career fluctuated with Republican mistakes. But he was more of an independent politician than a doctrinaire Federalist. He voted with expediency to benefit his state and his agricultural section of Virginia. Genuinely interested in developing education and transportation in Virginia, he served on a James and Kanawha River canal coanission and he worked with Thomas Jefferson in initiating the new ersity of Virginia. Of great significance to Breckinridge was the Virginia militia of which he was a member from his boyhood days during the Revolution until the War of 1812, when he attained the rank of brigadier general. But it was Breckinridge's estate, Grove Hill, that gave him the status of frontier aristocrat. Breckinridge amassed a land empire in the Valley of Virginia at a time when land could be bought almost for the asking. Soldier, surveyor, lawyer, educator, politician, and planter, Breckinridge led a full and interesting life and can lay claim to being another of Virginia's outstanding citizens. / Master of Arts

Various concentrations of grease were fed to a completely mixed activated sludge laboratory plant and the effects of blending and the addition of a surfactant on removal efficiencies were determined. Blended and unblended raw sewage containing grease was studied to obtain a comparison between the removal efficiencies by organisms acclimated to a synthetic substrate and organisms naturally present in raw sewage. Grease determinations were made by a modification of Loehr and Rohlich's wet analysis method using chloroform as the solvent. The experimental results indicated that grease was readily metabolized by the organisms of activated sludge, that the addition of a surface active agent decreased the removal efficiency, and that blending of raw sewage prior to biological treatment should increase removal efficiencies to greater than 90 per cent. / Master of Science

A method for solving general compressible three-dimensional boundary-layer flows is developed. The equations are initially placed in a Crocco-type form which makes use of similarity variables. A general solution technique which employs an implicit finite-difference scheme that is stable for negative transverse velocities is developed. The solutions for some 10° vertical half-angle elliptical cones of varying ellipticity ratios at up to 8° angle of attack at a Mach number of 7.95 are presented. Skin friction and heat-transfer-rate distributions are presented for all cases. Good agreement has been found with experiment for the heat-transfer rates on circular cones at angle of attack. It has also been determined that increasing ellipticity tended to produce large heat-transfer-rate gradients, and large increases in the peak heat-transfer rates and peak skin frictions. It has also been found that for even moderate angles of attack and small ellipticity ratios the peak heat-transfer rate and peak longitudinal skin friction fall close to the major axis of the cone. / Master of Science

In November, 1966, Tinker Creek, a hard water stream was introduced into Carvin cove Reservoir, a very infertile, water-supply reservoir. This provided an excellent opportunity to study some of the interactions between fish productivity and water quality. Physicochemical conditions were monitored in the reservoir from 1965 to 1968 by the Roanoke City Water Department. These records demonstrated that a significant water quality alteration resulted from the addition of Tinker Creek water. Total hardness and alkalinity were seen to increase from 10 - 20 ppm in 1965 and 1966 to 50 - 60 ppm by the end of 1968. Hydrogen ion concentrations, which averaged about 6.8 before the hard water introduction, had increased to about 7.6 in 1968. The hard water introduction caused variations in the physicochemical conditions of different areas of the reservoir during 1968. Waters nearest the hard water inflow ranged somewhat higher in dissolved nutrients. Bottom fauna distribution and abundance was affected. Greater concentrations of macrobenthic organisms were found in the area nearest the Tinker Creek inflow. High concentrations of fish, especially gizzard shad and white suckers, were found in the area near the hard water inflow. Length-weight relationships and condition indices suggest that bluegills and bullheads were in better physical shape in 1968 than they were in 1951. An age and growth study on the white sucker, Catostomus commersoni, indicated that growth rates had doubled in the sucker after the Tinker Creek water was added. / Master of Science