α- and β-Amylase activity were determined at 4°, -13°, -18°, and -23°C (39.2°, 8.6°, -0.4°, and -9.4°F) in systems with purified enzymes and in a system with sweet potato puree for different periods of time. In the systems with purified enzymes, commercially purified swine pancreatic α-amylase and sweet potato β-amylase at 0, 0.5, 1.0, and 1.5 μg/0.5 ml concentrations were used to react with 0.5 ml of a 2% potato soluble starch substrate for 112 days. In the system with sweet potato puree, samples prepared from cured and uncured roots were frozen and stored for 56 days. The cumulative enzyme activity was determined after different storage times. The stability of the enzymes as affected by low temperatures was determined in the sweet potato puree. In the systems with purified enzymes, cumulative α- and β-amylase activity at all storage temperatures studied increased as the storage time and enzyme concentration were increased, Both enzymes were still active at -23°C. In the system with sweet potato puree, α- and β-amylase were active at 4°C for up to 28 days, but were inhibited at -13°, -18°, and -23°C. In the cured sweet potato puree samples of the Centennial variety, α- and β-amylase were stable for up to 28 days at 4°C. Enzyme stability in samples from uncured roots of two varieties of sweet potatoes was not affected for up to 14 days of storage at 4°C, but decreased considerably thereafter. α- and β-Amylase stability in all sweet potato puree samples stored for 56 days at -13°, - 18°, and -23°C was not affected. / Master of Science

A program was developed which calculated sound pressure levels at an array of points in a room. Necessary inputs are the room dimensions, sound power or sound pressure levels for the sources, absorption coefficients for the room surfaces, the temperature, relative humidity, and if sound pressure levels are given for the source a description of the room in which this measurement was taken. This program allowed a maximum of twenty-five sources. Calculations were made at eleven octave bands from 16 Hz. to 16,000 Hz. and converted to dBA levels. The basis for these calculations was a modified room acoustics equations. The modifications were: a factor modifying the reverberant 1 term, continually monitoring directivity with respect to changing distance of receiver points from the source, the inclusion of air absorption on the direct term and corrections for receiver points in close proximity to room surfaces, The modification to the reverberant g term was to simulate the departure from the assumption of constant energy density in irregularly proportioned rooms. The modification when receiver points were near a room surface was simply the addition of corrections to calculated sound pressure levels. / Master of Science

Various estimation models and numerous sampling methods were used to estimate the size of a pumpkinseed sunfish (<i>Lepomis gibbosus</i>) population in a 1.16 hectare Virginia farm pond. After estimates were obtained, the pond was drained in order to compare estimated population size with actual population size. In all cases, population estimates were significantly less than actual population size. An examination of the underlying assumptions indicated that biases were attributed to mortality of marked fish, an increased catchability of marked fish due to marking, and the ability of fish to learn to avoid capture gear. Different gear combinations and use of different estimation models had no significant effect on the accuracy of estimates obtained. The study was designed to employ commonly used methods of estimating population size in a situation where underlying assumptions appeared relatively valid. It is apparent from the results of this study that underlying assumptions are often not met to the degree necessary to provide useful data. / Master of Science

Sources and yields of organic matter, suspended solids and nutrients in the Upper South River Basin were investigated during the summer low flow period of 1974. Parameters monitored at sampling stations in the basin included chemical oxygen demand, total suspended solids, turbidity, specific conductance, total phosphorus, total Kjeldahl nitrogen, nitrate, and iron. These data were used with flow and drainage area data to determine the relative magnitude and daily yields of materials from various sources. Sources of organic matter, suspended solids, and nutrients entering the South River included agricultural, forest and urban land drainage as well as domestic and industrial wastewater effluents. The yields of materials from the various sources were computed during an intense storm in May, wet weather flow in June, and dry weather flow in July. During the short term period of high storm flows, land runoff was the primary source of all pollutants. On the long term basis, however, wastewater effluents were the major contributors of all parameters except total suspended solids. Industrial effluents contributed the greatest proportion of chemical oxygen demand and total nitrogen. The Waynesboro sewage treatment plant supplied the greatest phosphorus loading. In comparison with forest drainage, agricultural land drainage was found to be a greater source of all materials monitored. Urban runoff was not analyzed separately, but it appears to contribute significant pollutant loads. It was found that reduction of phosphorus in the Waynesboro sewage treatment plant effluent may reduce excessive algal production in the South River below the city of Waynesboro. / Master of Science

Reproductive inefficiency is a major area of economic loss to most dairymen. Recent estimates for the United States indicate that this problem alone accounts for annual losses of 540 million dollars. Studies during the past several years have clearly illustrated the need for a complete, computerized reproductive management record system The reproductive management profile (RMP) has been developed to provide the dairyman with a current and. complete reproductive record on each cow and heifer in the herd. The forms for recording and reporting reproductive events have been condensed to a simple pocket format. Computer analysis is designed to coincide with routine herd examinations by a veterinarian. The output includes all routine reproductive events such as calving, estrus and breeding dates. In addition, two projected heat dates, days open, reproductive disorders, other disorders, uterine conditions and ovary conditions are listed. Monthly and annual summaries help make this a complete record system. / Master of Science

The problem of allocating non-identical machines among non-identical servers is considered under steady state conditions for the case of quasirandom input and exponential service times. Machines are assigned to operators with the objective of minimizing an expected cost model of the queuing system. Different classes of machines have different service rates and, for a given class of machines, the service rates are different among servers. Both dynamic programming and pattern search are used to solve the resulting optimization problem. Computational experience is presented, along with an analysis of the sensitivity of the model to errors in estimating the values of the parameters of the model. / Master of Science

The purpose of this project was to investigate the method of discrete least squares polynomial approximation and to provide an extension of the method which would allow for a reasonable data-fit while lowering the number of undetermined coefficients. Also, computer programs were to be provided so that one may use the extended method. This project is an outgrowth of work done by Dr. R. De an Riess, Mathematics Department, V.P.I.S.U. There exist several areas of investigation of the theory and some extensions of the computer programs which appear to merit future effort. Possible investigations of the theory include the interpolation result that was mentioned in the discussion of the extended problem, and error bound results. Possible extensions of the programs include the introduction of decision making capabilities so that the user need only specify the data and a tolerance level to achieve a good approximation, and the implementation of the extended programs on the central system. / Master of Science

A seismic reflection study was carried out southeast of the Brevard Zone in the Inner Piedmont province of southwestern North Carolina. Two geophone spreads approximately transverse to the regional strike were located 7 km and 9.25 km southeast of the Brevard Zone. The area of the study is underlain by Henderson Gneiss. Based on ultrasonic velocities from surface rock samples, early reflections on the seismograms from the two sites indicate that the Henderson Gneiss is approximately 2.8 km thick and the Brevard Zone is about 0.9 km thick. The inferred geometry of the reflecting interfaces indicates that the attitude of the Brevard Zone shallows to the southeast due to folding. Later large-amplitude reflections, beginning at about 6 km depth, are tentatively associated with the Lower Paleozoic sedimentary section as it exists in the Valley and Ridge province of northeastern Tennessee, implying that these sediments have been overridden by the Blue Ridge thrust sheet. A stratified igneous complex, or a gneiss with interlayered amphibolites, might also account for the large-amplitude reflections; however, regional geologic information seems to support the Lower Paleozoic section interpretation. / Master of Science

Hardware and software techniques have been developed to study water gas shift catalysts over a temperature range of 150°C to 400°C, a pressure range of 0 atmospheres gauge to 30 atmospheres gauge, and a space velocity range of 600 hr⁻¹ to 60,000 hr⁻¹ . The hardware consists of a 5-foot long 3/16 inch-I.D. stainless steel temperature controlled jacketed reactor over which temperatures can be maintained to within ± 2°C at 250°C and to within ± 4 °C at 500°C. The effluent from the reactor is sampled at 150°C and analyzed by gas chromatography for carbon monoxide, carbon dioxide, water, and other low molecular weight gaseous components. A computer program converts the conversion data to plots of - ln{(X_CO - X^eq_CO) / (X^O_CO - X^eq_CO) versus the reciprocal flow rate. The slopes at low values of 1/F are then divided by the weight of catalyst, and the quantity ln (kV/W) plotted against the reciprocal temperature to determine activation energies. Particle sizes studied were 20/60 mesh. Using the above reactor system, a sulfur-tolerant water gas shift catalyst was studied using a feed gas composition of 49% CO/49% H₂/2% COS. The composition of the catalyst was varied and an attempt was made to determine whether there were any "breaks" in the activation energy plots. Two types of breaks were observed which we tentatively ascribe to (a) a phase change, perhaps a melting point, at low temperatures ranging between 175°C and 350°C, and (b) a change to diffusion controlled reaction at higher temperatures in the region of 350°C to 400°C. We also report preliminary studies on a resistance drop technique for measuring melting points of molten electrolytes as well as a digital electronic interface between an Autolab 6300-02 digital integrator and a PDP 8/E minicomputer. / Master of Science

A disjunctive analysis technique was developed to investigate the relative importance of auditory and visual stimuli in eliciting initial approach and following responses in domestic fowl. 72 Canadian Athens random-bred chicks were tested at 24 or 36 hours post-hatch. A repetitive, tapping tone (4 per sec., 50 msec. duration, 500 Hz) served as the auditory stimulus, and a flickering light (3.5 pps, .8 fcl. intensity) served as the visual stimulus. Results are in agreement with previous reports that chicks of the ages tested respond primarily to auditory stimuli. However, a nonsignificant trend for an age-dependent increase in attractiveness of visual stimuli, with a concomitant decrease in attractiveness of auditory stimuli, was found. / Master of Science