A procedure was developed to subdivide a drainage area into units that respond similarly. These were defined hydrologic response units and were a funtion of soil texture, soil depth, land use, and hydrology group classification. A computer model was developed to generate excess precipitation for each hydrologic response unit based on the Mein and Larson and Holtan infiltration equations. Data for several major storms from a natural watershed, located in Virginia, was used to evaluate the technique. The results showed significant variability between response units reaffirming the need to consider the vegetative-soil characteristics separately. Sensitivity analyses were made to evaluate variations in soil texture, depth of A horizon, soil hydrology group classification, and land use relative to excess precipitation estimates. Interactions were not studied. Advantages of this system compared to a lumped-parameter model were discussed. The most important advantage, particularly for the planner, is that spatial uniqueness is maintained for all response units. / M.S.

In performing wind tunnel model tests of a two-dimensional nature, a grid constructed of 3.6 x 0.75 inch boards on 18 inch centers was used at the entrance of the tunnel. Important properties of the turbulent flow behind the uniform coarse grid were determined. The flow was found to be quite uniform at a distance of 38 bar widths downstream of the grid. Use of this flow to simulate atmospheric turbulent flows for testing sectional models of suspension bridges is discussed. The power spectra of the turbulence was found to agree quite well with the von Karman spectrum equation for atmospheric turbulence. The integral length scales were found to increase with increasing distance downstream of the grid. Integral length scales of the longitudinal turbulence component were found to increase in size as the mean velocity was increased. Measurements indicate that grid turbulence seems to model the atmospheric turbulence quite well for studies of suspension bridges and other elevated structures. Meaningful quantitative results may be obtained if geometric modeling of the integral length scales of the atmospheric turbulence is of minor importance for proper model response. / Master of Science / incomplete_metadata

Equations were derived to calculate the reflection points of acoustic rays emanating from a source to a receiver. Reflection points for up to three reflections could be determined if the location of the source, receiver and all reflecting surfaces were known. Assuming a point source, the distances along the calculated ray paths were used along with the power level of the source and the absorptive characteristics of all the reflecting surfaces to determine the sound pressure levels at specified receiver locations. A computer program was developed to perform the necessary calculations for reflection points and sound pressure levels. The output was in the form of ray tracing plots which showed the unique reflection paths for up to three reflections and the sound pressure levels at each receiver location. Comparisons were made between predicted and calculated sound pressure levels in a rectangular parallelopiped shaped room and a long narrow hallway. The results of this investigation showed a promising potential in the area of sound pressure level predictions and the use of ray tracing plots to provide a means of reducing the sound pressure levels. A particularly interesting point of the program was its ability to handle very irregularly shaped rooms which include slanted surfaces. / Master of Science

Males placed in one of two room sizes and one of two group sizes engaged in several group discussions, performed anagrams tasks, and served as members of a mock jury. Results indicated that subjects liked each other more in small groups than in large groups, that subjects in large rooms reported feeling more negative emotions than those in small rooms, that subjects felt more crowded in small rooms than in large ones, and that small rooms contained more information than large ones. Subjects performed better on the anagrams tasks, liking for group members increased, and reports of negative emotive feelings decreased as the experiment progressed. Results have theoretical and methodological implications since (1) social density is shown to be different than spatial density, (2) there are time-dependent effects, (3) "crowding" as an intervening variable cannot mediate observed effects of social density, and (4) subjects in the large. group, large room condition showed the greatest number of deleterious effects of treatment. Various theoretical mechanisms and their applicability to the present study are discussed. / Master of Science

Nine holes in the Blue Ridge, Valley and Ridge, and Alleghaney Plateau Provinces of Virginia provide heat flow values of 0.87 ± 0.07 mcal/cm² -sec , 7.7 ± 0.5 mcal/cm² -sec, 1.2 ± 0.1 mcal/cm²-sec and 1.4 ± 0.1 mcal/cm² -sec at Poor Mountain (37°02'N, 80°12'W), Hot Springs (38°00'N, 79°50'W), Back Creek (38°14'N, 79°49'W) and Vansant (37°12‘N, 82°06'W) respectively. The value of 0.87 mcal/cm² -sec agrees with Diment's Central Region for the eastern United States. Limited data support a model of moderately deep circulation of meteoric water possibly coupled with the heat generation of buried plutonic rocks to explain the origin of the hot springs in Hot Springs, Virginia. / Master of Science

The viscous power losses of a rotary-vibratory drilling system are estimated in this study. Rotational and pure vibratory losses are considered separately. This analysis indicates that considerable power is dissipated into the drilling fluid. Pure vibratory power losses of over 3,728 W (5 hp) are expected at frequencies equal to the first mode maximum response point for a drill column that is 152.4 m (500 ft) long. This is a frequency slightly less than the first undamped natural frequency of the drill column. For the same column, viscous rotational power losses of over 74.56 W ( 0.1 hp) are expected at rotational speeds of 10.47 rad/s (100 rpm). Rotational and vibratory losses increase with increases in the length of the column, fluid viscosity, and operating frequency. / Master of Science

The staff of the Donaldson Brown Continuing Education Center can benefit from the study in four ways: (1) The staff can gain information about the people who attend adult education programs. (2) The staff can obtain feedback on the quality and supportiveness of the Center facilities. (3) The program planning staff can determine the factors which are important for a successful conference. (4) The staff can gain information about the evaluation process which will provide the most useful information about the conferences. Knowledge about the characteristics of the average attender can be useful during program planning sessions. The average participant of the Center's programs was about 40 years of age, had a technical degree, had attended about three prior conferences in the last two years, and attended this conference to obtain technical information and to update work skills. The facilities of the Center were considered by the participants to be very conducive to adult learning and interaction. The Center staff is reinforced in their belief in the importance of comfortable lodging, ease, and coordination of registration, and helpfulness of the Center staff. Continued attention should be given to the selection of the conference speakers and the program content. These factors are vital to conference success and participant satisfaction. The Center's administrators became more aware of the need for several types of evaluative instruments which can be administered to different types of conferences. It is important that these instruments be carefully scrutinized and revised to ensure that they are providing the program planners with reliable information about the conferences. For the purposes of this study, only the closed-ended items were analyzed. The responses to the open-ended items, however, did provide valuable information for the planning of future conferences. / Master of Science

The role of sediments in regulating nutrient availability in lakes and reservoirs has been the subject of many recent studies. Classical theories concerning the regulation of phosphorus release from sediments by oxidation-reduction potential neglect the potential of microorganisms to transfer large amounts of phosphorus out of sediments. Aerobic surface sediments collected from the eutrophic Occoquan Reservoir, Virginia, were treated with ethylene oxide to reduce the populations of living organisms. These sediments served as the sole source of phosphorus in cultures inoculated with bacteria and/or blue-green algae collected from the Occoquan Reservoir. Inoculum composition was maintained for the thirty-five-day incubation period with selective inhibitors. An abiotic culture series served as a control. Cultures were harvested at five-day intervals and were analyzed for phosphorus fractions in sediment and medium, chlorophyll, bacteria in the sediments, and air dry weight of the sediments. Short-term (less than five days) release of total and inorganic phosphorus was roughly equal for all cultures. After five days growth of algae correlated with rapid transfer of phosphorus from the sediments. A large proportion of the released phosphorus was incorporated into the algae. Cultures containing just bacteria showed only slightly higher phosphorus release rates than abiotic cultures. Blue-green algae appear to act as a sink for phosphorus, permanently upsetting the phosphorus equilibrium between sediment and water. The sediments continuously release phosphorus to restore the equilibrium. Bacteria appear to have little effect beyond the mineralization of relatively small quantities of organic phosphorus. / Master of Science

The effect of a periodic source of a NO_x-SO₂ air pollution regime on the growth of forest trees was investigated. Radial increment growth studies were conducted to determine if correlations existed between emission levels of a source (predicted by production levels) and radial increment growth of forest trees. Three stands of loblolly pine, two of white pine, and one of sycamore proximal to the emission source were sampled by obtaining increment cores at d.b.h. (1.37 m from the base of the tree) from 50 trees in the dominant or codominant crown class of each stand. A multiple linear regression analysis utilizing annual radial increment growth as the dependent variable and the independent variables of annual production levels, total annual rainfall, annual seasonal rainfall, and age were used to evaluate all stands. An inverse relationship significant at the 0.001 level was demonstrated between growth and production levels in two loblolly pine stands and one white pine stand. The further analysis of these stands indicated respectively a 45%, 45%, and 10% theoretical reduction in diameter growth which was independent of symptom expression in white pine. Growth and production levels were not significantly correlated in the remaining loblolly pine stand and the sycamore stand; however, a positive relationship was exhibited in the second white pine stand. A field chamber study (utilizing charcoal filtered and nonfiltered air) with seedlings of red oak, sycamore, sweetgum, yellow poplar, white ash, green ash, and Virginia pine indicated significant inhibition of terminal elongation in Virginia pine and red oak in three locations surrounding the emission source. / Master of Science

Pairs of male subjects played an experimental game designed to investigate the antecedent conditions necessary for the development of cooperation. Subjects were assigned to one of four absolute power conditions and then were shifted to a condition of equal power. The results indicate that when individuals have been subjected to conditions of absolute power whereby another individual is determining their outcomes or payoffs, cooperation is facilitated by equity in payoffs. / Master of Science