Blood coagulation time was determined in five genetically diverse lines of chickens by the capillary tube method. Significant differences were found among lines for coagulation time suggesting genetic influences on this characteristic in chickens. Heritability of blood coagulation as estimated by paternal half-sib correlations was 0.13. The significant difference among lines and the low heritability of this trait indicated that a study of specific coagulation factors was warranted. Prothrombin time, thrombocyte concentration and plasma fibrinogen concentration was investigated in two of the most diverse lines to determine their relative contribution towards variation in coagulation time. Highly significant differences between lines were observed for prothrombin time and concentration of thrombocytes. Differences between lines for concentration of fibrinogen was not significant. The coagulation time and prothrombin time were positively correlated, where as the correlation was negative between coagulation time and thrombocyte concentration and between prothrombin time and thrombocyte concentration, The correlation coefficients between coagulation time and fibrinogen concentration were not significant. The percentage variation in coagulation time attributed to these three coagulation factors was 33 for females and 35 for males, Prothrombin time was the major source of variation in females while the contribution of each of these factors were comparable in males. / M.S.

The flow parameters involved in the transportation of sludge from the place of origin to the place of disposal has long been a problem to the sanitary engineer. To obtain the greatest efficiency in the design of pumps and pipelines the properties of sludge need to be thoroughly understood. This investigation examined the flow characteristic of raw and digested sludge from the Blacksburg Treatment Plant using a rheological approach. A Brookfield viscosimeter was used in the investigation and formulas developed by Krieger and Maron (1) were used to determine the shear stress and velocity gradient. A series of graphs involving shear stress vs velocity gradient were plotted. These graphs were compared to the Standard Newtonian and Non-Newtonian curves, in order to determine the flow behavior of the sludges. The results showed the method of analysis was satisfactory for determining the flow behavior of sewage sludges. The curves obtained showed that the raw and digested sludge examined was pseudoplastic in behavior and shear stress values for the domestic sludge showed it to be more viscous than the raw sludge. / M.S.

M.S.

The thesis shows a simplified representation for an armature rectifier driving a DC motor load. This representation was obtained from the nonlinear equations relating the output current of the armature rectifier into the DC motor as a function of the input control variable for continuous and discontinuous current conduction. Using this simplified representation, a velocity regulator with gears connecting the DC motor to an inertia load was examined by the Bode diagram method to observe the effects of twist in the load shaft and backlash in the gears on the stability of the velocity regulator. Velocity damping and friction were neglected in the analysis. It was discovered that the armature rectifier operating in discontinuous current presented stability problems which are not encountered in a velocity regulator using a conventional rotating armature supply to drive a DC motor. Linear stabilization techniques were used to stabilize the control system to overcome the effects of twist in the load shaft and backlash in the gears for both continuous and discontinuous conduction of the armature rectifier. / M.S.

The object of this thesis is to establish the necessary design criteria for a number of special feedback networks which were required to allow the final development of the Strip Mining Industry's first Automatic Crowd-Hoist Regulator. The introduction considers the purpose and needs for such a regulator by briefly outlining the present manual dipper loading operation. Section IV and Appendix 1 presents the analytical system requirements which are basically determined from an analysis of the system's inherent mechanical oscillatory frequency. Section VA is concerned with the development of the hoist and crowd motion transfer functions which are necessary to accomplish the stability analysis of the system. A general determinantal solution is obtained based on linear analysis to allow expression of the motion transfer functions as a factored polynomial. In section VB, the development of the necessary Crowd-Hoist feedback circuits is accomplished in terms of the system parameters defined from the analysis of the oscillatory mechanical system. Section VIA outlines the procedures to be followed in going from the basic mechanical system parameters to the specific control system hardware. The general requirements for a Bode analysis of the system GR is defined in section VIB, including the general procedures to follow in the utilization of the two lead compensation circuits provided. / M.S.

Production costs and production rates for harvesting hardwood pulpwood in western Virginia were empirically studied. The harvesting operations of felling, bucking, skidding, loading and delay were individually and collectively analyzed. Forty operators were studied during the period July-September 1965. Average production time for all operators to process 1000 pounds of wood from the stump to a loaded transport device was 39.8 man-minutes, 8.0 power saw minutes, and 3.8 tractor minutes. Average cost for the total operation was $1.29 per 1000 pounds. Operators studied were stratified by amount of equipment used and productivity in truckloads per day. Variation within strata obscured most differences between strata. However, the data indicated that two load per day operators had a lower cost per 1000 pounds than the one load per day operators. Recommendations for improved harvesting efficiency center on improved organization of the harvesting processes, such as temporary storage, rather than on larger or different equipment. / M.S.

Results are presented on tests of reinforced concrete T-beams with a flange 20 inches wide by two inches thick setting on a stem five inches deep and four inches wide. These beams were loaded at the quarter points of an eight-foot span and also at the end of cantilever sections of two feet. The beams were loaded until they collapsed. The reinforcing steel was varied at the support section, but remained constant at the center. Moment-curvature information is developed from the experimental results, and conclusions are drawn concerning present theory for deriving analytical moment-curvature relationships for reinforced concrete sections. Ultimate concrete strain in confined sections is reviewed in light of the experimental results. Discussed also are current theories for calculating ultimate loads for indeterminate reinforced concrete beams. / M.S.

The transmissions of some optical crystals were determined for the vacuum ultraviolet using a SeyaNamioka monochromator. The characteristic low wavelength cutoffs were determined for crystals transmitting in the region 1050-2000 A. The crystals so studied are: MgF₂, NaF, LaF₃, SrF₂, BaF₂, BeO, Al₂O₃, KD*P, KDP, ADP, NaCl, NdF₃, KBr, CdF₃ and PrF₃. The techniques employed in the experiment and the data obtained will be presented. / Master of Science

The principle objective of this study was to determine whether the Virginia property tax, as it is applied to forest lands, may have harmful effects on forest management in Virginia. In order to accomplish this objective, an investigation was made of the theoretical aspects of the general property tax as applied to forest land, including a definition of tax equity as applied to forest taxation, Next, the property tax situation in Virginia, specifically as related to forest lands, was investigated. The usual situation of the general property tax as applied to forest lands was found to produce two serious equity faults, deferred yield bias and parcel bias, which could be harmful to forest management. It was also inferred that the general property tax is a variable cost as applied to forestry, and as such, influences management decisions. When the Virginia property tax situation was compared to the general case, it was found that the situations were not substantially different. Alternatives to the general property tax on forest land were discussed, It was decided that only the productivity tax meets the defined standard of equity. It was concluded that the forest tax situation in Virginia will allow the faults which are found in the general property tax situation to occur in Virginia. The effects of the presence of these faults in the Virginia situation and the magnitude of these effects were two subjects which were left for future study. It was felt that a firm understanding of the nature of these faults in the general property tax was prerequisite for further studies. Thus, in order to determine the actual effects of the Virginia real estate tax on forest management decisions future intensive study is necessary. / Master of Science

Small-deflection plate equations are presented in terms of the midplane plate deformations and the temperature distribution within the plate, which is assumed independent of the plate deformation. The plate boundary conditions are presented in a general form and are suitable for solutions involving either fixed, free, or hinged edge conditions. The temperature distribution within the plate is assumed to be governed by Poisson's equation and a specified temperature distribution over the surfaces of the plate. Solutions for the temperature distribution are given in terms of a power series with respect to the plate thickness coordinate, the coefficients of which are dependent on the midplane temperature distribution and the midplane temperature gradient in the plate thickness direction. Out-of-plane plate deformations are discussed for plates with fixed edges. Discussions of plate deformations are also presented in which the temperature distributions result from constant heat generation within the plate and from radiation absorption. / Master of Science