A framework for evaluating the risk of water pollution from the application of liquid dairy manure to agricultural fields was developed and applied. The GLEAMS (Groundwater Loading Effects of Agricultural Management Practices) (Ver 2.1) model was used to simulate NO₃-N leaching below the root zone for different land application rates of liquid dairy waste for fields in Georgia and Texas. Probability distributions of yearly-maximum nitrate concentrations were developed for each application rate at each site using the simulated nitrate concentrations. The probability of failure (exceeding 10 mg/L NO₃-N) for each application rate was determined from its corresponding distribution. An appropriate fine for farmers based on probability of failure for different land application rates was determined through economic analysis. The expected risk to farmers in monetary terms was determined for each application rate based on possible fines and the probability of failure. The monetary risk of nitrate leaching to ground water was compared to the social value of ground water. The probability of failure for liquid dairy waste application rates between 200 to 800 kg·N/ha/yr ranged from 0.0022 to 0.74 for Tifton, GA. The probability of failure for liquid dairy waste application rates between 0 and 1000 kg·N/ha/yr ranged from 0.00 to 0.85 for Overton, TX. The maximum application rate that was environmentally acceptable for both Texas and Georgia was 250 kg·N/ha/yr based on the probability of failure. Fines of $1100/ha and $700/ha for the Georgia and Texas sites, respectively, would provide farmers with economic incentives not to exceed an application rate of 250 kg·N/ha/yr. These fines resulted in risks to farmers of $814/ha in Georgia for 800 kg·N/ha/yr application rate and $595/ha in Texas for 1000 kg·N/ha/yr rate. This compares with a social value ranging from $860/ha to $1432/ha of clean ground water. / Master of Science

A method has been developed whereby various physical properties of middle distillate fuels may be rapidly and accurately calculated by a group property approach from data obtained from a directly coupled Liquid Chromatograph -⁻¹H Nuclear Magnetic Resonance Spectrometer (LC-⁻¹H NMR). The physical properties include cetane number, cetane index, density, specific gravity, pour point, flash point, viscosity, filterability, heat of combustion, cloud point, volume percent aromatics, residual carbon content, and initial, 10%, 50%, 90%, and end boiling points. These property predictions have accuracies approaching the error for measurement of the experimental physical property and require less than two hours analysis time per fuel. An interface was developed between the NMR spectrometer and a personal computer to aid in automation of the LC-⁻¹H NMR data collection and to perform off-line analysis of the LC·⁻¹H NMR data. This interface and all associated software is described. Also presented is a series of model compound studies in which the physical properties of pure hydrocarbons (i.e., alkanes, monocyclic and dicyclic aromatics) were predicted by a similar group property approach. / Ph. D.

The effect of a single spray coating of 60.9% D.C. 801 silicone resin, with a 0.3% cobalt on the dry resin basis, on (1) the initial overall heat transfer coefficient, (2) the overall heat transfer coefficient under accelerated scale forming conditions, and (3) the corrosion resistance of 1.5” o.d. mild steel evaporator tubes, 12 B.W.G. was investigated. Preliminary tests were made with silicone resins D.C. 801, 993 and G.E. 9975, 9982, 9989 to select the resin to use in the above tests and to develop a precoating treatment for the evaporator tubes. The evaporator used for the investigation was an experimental, horizontal tube evaporator using the two 1.5” o.d., 21” mild steel tubes, 12 B.W.G., having an effective heating area of 1.113 ft.². The operating conditions for the test were steam, 85% quality, at 45.75-46.25” Hg. abs. and body pressure of 7.8-8.5” Hg. abs. giving an effective temperature drop of 80-85°F. Evaporator feed for the “Normal Tests” was tap water; for the “Accelerated Tests” was gypsum solution, saturated at 55-65°F.; for the “Corrosive Medium Tests” was 3% NaCl solution. The coated tubes had an initial overall coefficient of heat transfer, “U”, 11% lower than that of commercially clean tubes. In the accelerated scale forming tests the “U” of the coated tubes decreased 24.6% in 32 hours; while that of the commercially clean tubes decreased 47.4% in 24 hours. The silicone resin coating protected the tubes from corrosion in 3% NaCl, boiling in natural convection, for the duration of a 24 hour test. / M.S.

This study provides a survey of local school board members in the Commonwealth of Virginia which investigates attitudes and perceptions of merit pay for teachers. In addition, criteria considered important components of a merit pay program for teachers in Virginia are identified. Case studies of selected school systems in Virginia provide a comparison of the criteria with the characteristics of merit pay programs which are now or have been operational at sometime since 1960 in school systems in Virginia. Findings indicate that the variables of sex, educational level, occupational status, length of service on the school board, and the location of the school system served significantly effect school board member attitude and perceptions of merit pay for teachers. In addition, the case studies indicate a relationship between school board members' perceptions of merit pay and the actual operational characteristics of merit pay programs. / Ed. D.

The study was designed to provide empirical data investigating children’s level of sense of humor with the severity of the hassles reported by the children. The sample included 82 children, 50 boys and 32 girls, ranging in age from 8-11 years, and representing the third, fourth, and fifth grades. Both male and female children participated in the study. The Hassles Scale for Elementary School Children (HSESC), a 22-item checklist, was administered to the children to assess the frequency of selected important hassles and the severity of the hassles. Subjects indicated those items that occurred in the past week and rated the severity of all the hassles on a 5-point Likert type response scale. The Children's Self-Rating of Humor (CSRH) questionnaire, a 20-item questionnaire, was completed by the children to evaluate children's level of sense of humor. Subjects rated each question on a 5-point Likert type response scale. Subjects were administered the scales individually and in small groups. To provide a more in-depth understanding of children’s use of humor, a subsample of 12 children, six boys and six girls, randomly selected to represent the three grade levels and high and low humor scores participated in a follow-up interview. The results of this study did not provide support for the contention that children with a high sense of humor would report hassles as being less upsetting as compared with children with a low sense of humor that would report hassles as being more upsetting. Further results seemed to indicate that the use of humor in stressful situations depended more on the child’s perception of the severity of the hassles rather than on the child's perceived level of sense of humor. The less upsetting the stressful situation was to the child the more likely the child would use humor and the more effective humor was in dealing with the stressful situation. More importantly, this study indicated that when humor was used it was not specific to the stressful situation but rather as a distraction, a more general coping mechanism. A recommendation for future research should include the need for a better understanding of how children produce humor in stressful situations. Also, future research should focus on investigating the differences in the effects of different types of humor on stressful situations and the timing of using humor on whether it is an immediate or delayed response to a stressful situation. Future studies should focus on the cognitive processes of children’s humor when applied to stressful situations. / Ph. D.

Within the past two decades, the planning arena has changed considerably and increasing awareness of the impacts of utility generation, intensifying pressure from the public and regulators, and growing competition from other energy and electricity suppliers have made the utility planning process rather complex. The variety of players in utility planning has introduced new priorities and a new set of competing objectives. Increased resource scarcity, the requirement for economic efficiency and the need to view the electricity production and utilization process in its entirety also necessitate an integrated resource planning approach, resulting in a wider array of expansion alternatives that must be evaluated. Another characteristic that makes planning so complicated is the uncertainty in the factors that influence the cost of the power system plan. Public concern for the environment has resulted in a series of legislations for controlling emissions of acid rain precursors (SO₂ and NO_x) and other pollutants. More and more regulators are also requiring electric utilities to internalize environmental externalities in their planning processes. The potential for new legislation on currently uncontrolled effluents like CO₂ likewise remains. There is thus a need to examine the modeling of emissions that would reflect not only the cost of control but the environmental impacts of these emissions as well. This thesis combines the features of the trade-off and decision analysis techniques to address the multiplicity of objectives and the uncertainties of planning. It draws on Saaty's analytic hierarchy process (AHP) and the interdependent data analysis (IDA) technique developed at Virginia Tech to develop priority weights among objectives and probability distributions of uncertainties. It elucidates the relationship between the competing techniques of trade-off analysis and the method of weights in terms of the economic theory of the firm. The confidence intervals determined with the IDA technique are then used to obtain a range of alternatives that satisfy the requirements of both approaches for evaluation by the decision maker (DM). Special attention is given to the environmental impacts of the generation plan and the model accounts for these issues as attributes in the planning process as well as being legislation uncertainties. / Ph. D.

Master of Architecture