A brief introduction to the problem and importance of solid-solid contact as well as to the nature of surface topography is given. A number of experimental techniques, both direct and indirect, for determining the true area of contact between surfaces as well as a number of theories for predicting contact areas in the case of elastic, plastic, and elasto-plastic deformation of contacting surface asperities are reviewed. The effect of tangential loading upon the area of contact is also reviewed. In order to implement a previously established goal of observing the nature of contact between transparent models of scaled-up surfaces, a procedure for three-dimensional model design, a technique for model fabrication, and an experimental apparatus have been developed. A computer program to predict points of contact and elastic contact parameters between macroscopic surface models is presented. Determining the range of application of the Hertz equations is discussed. The computer program is used to predict the contact parameters between the three-dimensional surface models developed. For this situation the nature of contact was found to vary from the case of a single pair of asperities dominating elastic contact to the case of multiple asperity contact between several pairs of contacting asperities. / Master of Science

The thesis outlines the need for a method of communicating concepts of environmental action, reviews environmental movements and simulation gaming theory, proposes methodology and learning objectives and describes an environmental simulation game named ''Community". The game simulates a small town with four industries (food, housing, textile and automobile manufacturing) that employ four to thirty-three players who exchange money, pollute, and vote on community issues. The game rules, playing board, player roles, event cards, tokens, game operation and participant reactions are described. The conclusion states the game of ''Community" represents a design that involved individuals in participatory, decision making situations concerning economic, political and pollution processes, A need is stated for additional research on the effects of simulation gaming. A bibliography lists sources consulted on environmental movements and simulation gaming. The appendices contain the game model elements in a playing form. The author's vita notes a university background in history and education with work experience in community organization. / Master of Science

The purpose of this study was to develop a valid and reliable scale to evaluate the adequacy of learning environments in day care centers that would be easily administered by professionals and nonprofessionals. The Learning Environment Checklist (LEC) that was developed consists of fifty yes-no questions that can be answered during a half hour observation of a day care center. The LEC was administered 182 times in 27 day care centers by day care personnel, students, parents, and licensing agents. The KR-20 estimate of reliability was computed to be .82. The standard error of measurement was 3.05. Construct validity was established through the internal consistency aspect of the KR-20 and through analyses of variance. Highly significant differences among centers were established by licensing agent observers. Less sUbstantial differences were found by nonagent observers. / Master of Science

A feasibility study to determine the feasibility of neutron radiography with the VPI & SU Research Reactor has been completed. Various experimental facilities of the reactor were tested to determine which gave the best beam parameters. The beam parameters considered were: 1) thermal neutron flux; 2) thermal to fast-flux ratio; 3) gamma vs neutron relative film exposure ratio; 4) collimator length vs diameter ratio. It was found that the north beam port best met the necessary requirements. The direct exposure method utilizing a commercially available gadolinium paint was decided upon for X-ray film exposure. The resolution capabilities of the gadolinium paint converter screen were determined for several screen thicknesses using a cadmium test object. Exposure times and object limitations were found for the combination of the X-ray film, converter screen, and neutron beam of the north beam port. The test devices used were: 1) various thicknesses of acrylic plastic; 2) plywood and white pine test pieces; 3) thorium and natural uranium slugs; 4) enriched uranium fuel plate; 5) used and unused boral control elements; 6) miscellaneous small test objects. The results were, in general, good. Exposure times and limitations were found to be in agreement with other published works. Any significant differences in the technique's capability with other facilities were noted in the discussion of procedures and results. From the results of this work, neutron radiography can be successfully carried out on the VPI & SU reactor with small objects while further development should allow studies to be made of larger objects. / Master of Science

An economic description and analysis of Christmas tree production was made for the benefit of Virginia's farm and other landowners. The purpose of the study was to aid in determining if investment in Christmas trees was likely to be economically successful, and to improve plantation management on existing plantations. Basic production and marketing data was collected from the state's growers, and used to describe and recommend certain operations commonly involved in the production process. Evaluation of the operations was based primarily upon financial considerations, with emphasis on cultural effectiveness whenever possible or appropriate. A computer analysis program was also developed which, given a set of input data, calculates the present net worth of the investment and break-even price per tree using a discount rate of 12 percent. In addition, the internal rate of return, and yearly and accumulated cash flows are presented. It was found that if the operations recommended in the study were carried out on a five-acre plantation over a production cycle of nine years that the internal rate of return could be expected to range from 9.4 percent for a high-cost operation and $1000 per acre land cost, to 39.8 percent for a low-cost operation and a $100 per acre land value. The primary financial disadvantage of Christmas tree production was found to be the large negative cash flow incurred up to the last year of the cycle. The computer program developed in this study has been stored on the VPI & SU Extension Division's Computerized Management Network so that it will be readily accessible to prospective and current Christmas tree growers. / Master of Science

From data and concepts in the literature, DEER, a FORTRAN IV program that operates on an IBM 370/65 computer, was written. The general purpose population simulator was designed for managers of white-tailed deer (Odocoileus virginianus). It is based on a dynamic age and sex-specific algorithm, unifying bioenergetic, sociological, hunter, and population characteristics. The system determines a management plan that will stabilize a population under the conditions specified. The system is also designed to be used for examining deer populations and for educating students on wildlife ecology and management. The concept that achieving a constant sex ratio can be used to stabilize a population was explored. The results indicate that a population will stabilize with any sex ratio when all management activities are oriented toward achieving such a sex ratio. An increase in the proportion of doe deer in the herd results in an increase in the allowable harvest but causes a decrease in the ratio of the antlered(trophy)-to-antlerless deer changes with a population natality change. A static management strategy (e.g. to achieve a constant ratio of antlered-to-antlerless deer) results in unstable (and probably suboptimal) harvest when the reproductive rate, adult sex ratio, and fawn sex ratios are dynamic. DEER is a decision aid useful for replacing rule-of-thumb management. / Master of Science

M.S.

Ph. D.

The purpose of this study was to systematically explore the potential for role conflict based on bureaucratic and professional value orientations in prospective and first-year teachers. The hypotheses of the study were: (1) Beginning students in the secondary teacher education program define their role expectations in relationship to that of the school bureaucracy; (2) Pre-student teachers in the secondary teacher education program define their role expectations in relationship to that of the teaching profession; (3) Student teachers in the secondary teacher education program define their role expectations in relationship to that of the teaching profession; (4) First-year secondary teachers, upon completion of the equivalent of one university quarter of actual teaching, define their role expectations in relationship to that of the school bureaucracy; and (5) Role conflict is found in persons who perceive their role expectations based on value orientations to both the bureaucracy and the profession. Of the four groups studied, teachers with actual teaching experience exhibit more role conflict than the other three groups. The discipline divisions of mathematics, science, social studies and English in the secondary teacher education program at Virginia Polytechnic Institute and State University provided the population for the study. Four groups in the secondary teacher education program were studied: (1) beginning teacher education students; (2) pre-student teachers preparing to student teach; (3) student teachers; and (4) teachers of the same teacher education program who had completed their first 10 weeks of actual teaching. Each group represented different levels of teacher education experience. The Teacher Value Orientation Questionnaire was developed to assist in the data gathering procedures to support or reject the hypotheses of the study. The instrument was designed to produce bureaucratic and professional responses toward selected teaching situations. The instrument was also designed to determine conflict in expected teaching roles by the inclusion of paired items, one item bureaucratically oriented and the corresponding item professionally oriented. The process of analyzing the data diverged into three stages: (1) determining commonalities found in the response patterns of the subjects; (2) determining the relationship of subject demographic variables to their value orientations; and (3) determining conflict in the responses of the subjects to 10 paired items on the questionnaire. The results of the analysis of data supported the general hypothesis of the study: The type of value orientation of each subgroup and the degree of conflict response reflected the amount of teacher education experienced by the subgroup. / Ed. D.

To compare the bird utilization of various residential areas, and to determine the components of the habitat associated with certain birds, bird counts and habitat measurements were made in seven neighborhoods. These. suburban neighborhoods differed in age, housing density, architectural design of the buildings and evidence of the habitat type prior to development. Birds seen or heard were counted in 4-minute periods (28 in each of two winters, 21 in one breeding season) in three 0.84 ha plots in each neighborhood. Measurements were taken of architectural features (eaves, vents, and an ornamental design), vegetation (including deciduous and evergreen volume in six horizontal layers, plus area of lawn and garden), A attraction devices (feeding stations and nest boxes), and sources of disturbance (housing density, vehicles, dogs and cats). Bird species diversity and degree of utilization by most of the common bird species were found to be different among the residential areas, during both the winter and breeding season. Some significant differences were also found among streets within neighborhoods. Housing developments built within wooded areas had consistently greater bird species diversity than developments of approximately the same age built on open ground. Within each group, species diversity increased with the age of the neighborhood. The multiple regression equations of the most common winter and breeding birds and bird species diversity contained 1 to 4 (mode=2) significant independent variables. Mourning doves (Columba livia) were associated with shrubby vegetation, particularly evergreens; (winter R² =0.82, spring R²=0.70). Blue jays (Cyanocitta cristata) preferred wooded, less open neighborhoods; (winter R²=0.65, spring R²=0.79). House wrens (Troglodytes aedon) were correlated with area of gardens and moderately high deciduous cover; (spring R²=0.40). Mockingbirds (Mimus Polyglottos) were most common in open residential areas with some shrubs (particularly evergreens); (winter R²=0.38, spring R²=0.59). American robins (Turdus migratorius) were associated with deciduous and evergreen vegetation up to a height of 30 ft; (spring R²=0.82). Starlings (Sturnus vulgaris) were ubiquitous, though more common in areas of dense housing; (winter R²=0.37, spring R²=0.34). House sparrows (Passer domesticus) were also associated with areas of dense housing and utilized ornamental architectural designs; (winter R²=0.69, spring R²=0.96). Common grackles (Quiscalus quiscula) were most common in areas with abundant vegetation, low evergreens in particular; (spring R²=0.65). Cardinals (Richmondena cardinalis) were associated with deciduous shrubs and gardens; (winter R²=0.81, spring R²=0.71). Evening grosbeaks (Hesperiphona vespertina) were also correlated with area of garden (winter R²=0.60); but field observations showed their affinity for feeding stations. Purple finches (Carpodacus purpureus) were shown to be correlated with feeders; (winter R²=0.38). Dark-eyed juncos (Junco Hyemalis) showed an affinity for gardens, and were observed less often in the heavily wooded neighborhoods than elsewhere; (winter R²=0.56). White-throated sparrows (Zonotrichia eucophrys) were associated with low shrub growth, particularly evergreen, and avoided areas with open expanses of lawn; (winter R²=0.77). Song sparrows (Melospiza melodia) were correlated with volume of vegetation near ground level; (winter R²=0.29, spring R²=0.35). / Ph. D.