Service workers who are paid in tips experience a particular type of occupational uncertainty. It stems from the lack of contract securing wages, When wages, the terms of the work exchange, are not specified, then the outcome of work exchange is uncertain. The attitude that develops in response to uncertain exchange outcomes is defined as occupational Vulnerability. It serves as the study's dependent variable and is researched within the context of waitress work. / Ph. D.

The purpose of this study was to determine the knowledge level of vocational laboratory teachers in technical colleges and institutes in Alabama regarding tort liability concerning negligence. Furthermore, the study sought to determine the extent to which these same teachers observed and enforced safety practices in the conduct of their vocational laboratory classes. The investigator examined whether relationships existed between knowledge and practice and the factors of location--urban, suburban, or rural, level of education, teaching experience, age, gender, and industrial experience. Two hundred and ninety-seven vocational laboratory teachers in the technical colleges and institutes in Alabama participated in the study. The researcher did not make a random selection of vocational laboratory teachers, but included all vocational laboratory teachers as identified by the president/director of each institution upon the researcher's visit to the institution. A three-part questionnaire was used in collecting the data for this study. Part A contained eight items designed to collect personal data relative to the participants. Part B was. composed of twenty items designed to assess the knowledge of the participants concerning tort liability and negligence. Part C was composed of twenty-four items designed to assess the practice which related to the participants as vocational laboratory teachers. The Statistical Package for the Social Sciences (SPSS), second edition (1975), was used inasmuch as the frequencies, percentages, and correlations could be computed by this one program. The Pearson productmoment coefficient of correlation was used to determine the relationship between knowledge and practice. Chi square (χ²) was used to determine the relationship between variables for both knowledge and practice items. No significant relationship was found between knowledge and practice. There was no significant relationship between the variables of location, level of training, teaching experience, gender, age and industrial experience and the knowledge level of vocational laboratory teachers regarding the body of law concerning tort liability regarding negligence. There was no significant relationship between the variables of location, teaching experience, age and industrial experience and the safety practices and procedures used by the vocational laboratory teachers. The null hypotheses for these variables were retained. There was. a significant relationship between the variables of gender and level. of training and the safety practices and procedures used by the vocational laboratory teachers. The null hypotheses for these two variables were, therefore, rejected. / Ed. D.

The problem addressed by this study was that of determining whether significant differences existed among selected apprehensions concerning work, church, social, and family life of sample groups drawn from the black and white faculties in selected Virginia Community Colleges where student population are no less than 10 percent black. The subjects consisted of 256 community college faculty of which 190 faculty members responded. These subjects consisted of 75 black faculty members and 181 white faculty members in 9 selected Virginia Community Colleges. The study utilized the descriptive-survey research design to define and interpret the problem under investigation: (1) the willingness of the faculty members of the opposite race, (2) the kinds of people with whom black and white faculty members were most willing and unwilling to associate, and (3) the apprehensiveness of the faculty members and the intensity of such apprehension in campus-related situations. To answer the first concern of the study, a twenty-item questionnaire containing a rating scale was constructed. The rating scale was designed to ascertain the attitudes of faculty members in Different Role Behavior Situations. To respond to the second concern of the study, a list of twentyseven items were derived from pertinent literature. The subjects were asked to indicate by selecting only one response from two categories consisting of six items each and from "yes" or "no" in fifteen attitude situations. To respond to the third concern of the study, a twenty-item questionnaire containing a numerical rating scale was constructed. The rating scale was designed to ascertain the apprehensions of faculty members with respect to campus-related situations and determine the relative intensity of each. The Statistical Package Program SPSSH, Version 6.01 and contributed programs in the computer user's library at Virginia Western Community College were used to test chi-square between groups. Further, analysis of data using the Wilcoxan and Friedman tests also contributed to the computer user's library at Virginia Western Community College were used. The analysis was done on the Hewlett-Packard System 3000 in the computer center at Virginia Western Community College, Roanoke, Virginia. The findings revealed a relationship in the data to support conclusions concerning the varying degrees of apprehension related to role behavior, interpersonal reactions, and campus-related situations. These conclusions are summarized below. In the area of role behavior as it related to levels of apprehension expressed by respondents the following conclusions can be drawn: 1. The analysis of the data suggests that there exists a relationship between years teaching experience and the respondent's expressed level of apprehension about associating with members of the opposite race. Since this relationship was indicated by the chi-square test, but not confirmed by the Wilcoxan test further study in this area is needed before a conclusion can be reached. 2. The data analysis indicated a relationship between degree of apprehension a respondent expressed about associating with members of the opposite race and the respondent's own race. Additional analysis of the data indicates that blacks are less apprehensive than whites. 3. The analysis suggests there is a relationship between the respondent's sex and the degree of apprehension expressed concerning association with members of the opposite race. Males appeared to be more apprehensive than females collectively. Also, white males appear to be more apprehensive than black males and white females more apprehensive than black females. Additional investigation into the question suggest there is a relationship between sex and the degree of apprehension among whites. The data did not show a statistically significant relationship between sex and degree of apprehension among blacks. Analysis of individual survey items suggested a relationship between sex and the degree of apprehension in two social situations: (a) joining a club where most of the members are women and (b) joining a church where half of the members are of the opposite race. The examination of the responses related to different kinds of interpersonal reactions revealed the following trends: The data suggests a relationship between race and characteristics of individuals of the opposite race with whom the respondents would be most willing to associate. The data did not produce statistically significant findings that a relationship exists between race and the characteristics of individuals of the opposite race with whom the respondents would be most unwilling to associate. Neither did the analysis suggest a relationship between sex and characteristics of individuals of the opposite race with whom the respondents would be most willing or unwilling to associate. An examination of the data related to campus-related situations suggested that: 1. There is a relationship between degree of apprehension expressed and race, with blacks being more apprehensive than whites. 2. There is a possible relationship between degree of apprehension expressed and sex with white females expressing less apprehension than black females. / Ed. D.

Veracity of past analyses on the impact of impingement and entrainment of fish in power-plant cooling systems was questioned. Density-dependent dynamics were hypothesized as variable, not constant, making previous analyses based on constant density-dependent or density-independent mortality in error. This hypothesis was tested with a simulation model based on complex biological and behavioral mechanisms for individual fish, thereby forgoing the need for assuming the kind of mortality exhibited by a fish community prior to the analysis. Yellow perch and walleye in Oneida Lake, New York, were focal points of this test, and data taken in 1972 from Oneida Lake were used to validate the model. Model experiments consisted of varying turbidity, water temperature, impingement and entrainment, and abundance of young perch and walleye. Under most conditions in the experiments, individual growth was unchanged, and predators maintained a high frequency of full stomachs. Exceptions were that water temperature influenced growth and that adult walleyes went hungry when fry of both species were limnetic. Mortality of young perch proved depensatory and that of young walleye density-independent. Mortality of walleye fry was inversely influenced by abundance of young perch. High levels of turbidity greatly enhanced fry survival for both species. Impingement and entrainment reduced survival of young perch and young walleye by 43 and 30 percent, respectively. Expected losses due to density-independent impingement and entrainment were 3 and 2 percent. Depletion of young perch occurred because of their depensatory mortality; depletion of young walleye occurred because their survival was related to abundance of young perch. High abundance of young perch and high turbidity dropped mortality to density~independent levels of about 3 percent. These mitigating effects of turbidity and high abundance showed that mortality could shift from density-dependent to density-independent dynamics. The relationship between abundance of young perch and mortality of young walleye meant that no analysis based on a single species could properly assess impacts of impingement and entrainment in Oneida Lake. The conclusion was that density-dependent and density-independent mortality are variable and are influenced by certain conditions: 1) compensatory mortality is based on density-dependent growth, 2) density-~independent and depensatory mortality are based on density-independent growth, 3) density-independent mortality occurs when predation removes insignificant numbers of prey, and 4) depensatory mortality occurs when predators remove large numbers of prey. / Ph. D.

Presently, there exist significant discrepancies between experimental and theoretical predictions of flat-plate solar collector performance. There is a need to identify both those areas of analysis which need improvement as well as those which are already adequate. Two new methods of absorber-plate thermal analysis which can be used within the framework of existing theory were developed. The first method used the separation of variables technique in a unique manner to solve exactly for the coupled axial and transverse temperature distributions in an absorber plate-tube assembly. The conventional assumption of an overall uniform loss coefficient U_L was used in the analysis. The first method is practical only for parallel-flow collectors. The second method used two sectionally uniform loss coefficients -- U_LI for internal collector sections and U_LE for edge sections -- to evaluate collector performance. The second method is applicable for both parallel-flow and serpentine configurations. The validity of two assumptions commonly made in flat-plate collector analysis was investigated using the new methods. The first assumption that was investigated involved the approximate treatment of the effect of axial conduction on the absorber-plate temperature distributions. Results from the first new method were graphically compared to the predictions of approximate analytical treatments given by Whillier and Phillips. The comparisons showed that, for conventional flat-plate designs, the method given by Phillips yields values of the heat removal factor F_R accurate to within 1 per cent. The more commonly used method given by Whillier is accurate to within 10 per cent for conventional designs. The second assumption that was investigated dealt with the manner in heat losses from the collector peripheral area are taken into account. Results from the second new method indicated that, for typical collector designs, the conventional edge loss treatment yields values of instantaneous collector efficiency n_c accurate to within 3 per cent absolute and 15 per cent relative. Analysis of the net effect of the two improvements indicated that approximate axial and edge-loss treatments are not the primary source of error between experimental and theoretical results for typical collectors. The solution technique developed in the first new method has potential applications to a number of conduction-convection problems. The second new method has the inherent capability to better evaluate performance and design questions related to edge effects. Convenient relations between the mean plate and fluid temperatures and the heat removal factor F_R were obtained. The relations apply for parallel-flow analysis under the assumption of a uniform loss coefficient U_L. / Ph. D.

Heliothis zea (Boddie) (Lepidoptera: Noctuidae) density, development, and relationships with host crops were studied in eastern Virginia. Six instars occur. The larval population in corn is the reservoir for the generation in soybeans. An estimator, based on the reservoir population, permitted calculation of the larval density in soybeans. An index, based on blacklight trap and emergence data, permitted precise timing ot peak moth flight to soybeans. Regression analyses of biotic and abiotic factors revealed that soybean plant morphometrics best explained corn earworm densities. Discriminant analyses on empiricala priori soybean field susceptibility categories (described by plant morphometrics) classified five levels of anticipated maximum larval densities 80 - 98 percent correctly. Development of highest larval densities was synchronized with overall plant growth and specific pod development: third and fourth instars were present during rapid pod elongation, while fifth and sixth were present during rapid pod volume increase. / Master of Science

An objective function that is suitable for both stable and unstable equilibrium states since it is guaranteed to assume a relative minimum at any equilibrium state is presented. The objective function, which is the inner product of the equations of equilibrium (algorithm 2), is compared with another objective function which, for a static problem, is the total potential energy (algorithm 3). The method of formulating the mathematical model for algorithm 2 is presented in detail. Algorithm 2 is found to be less efficient than algorithm 3. However, it is demonstrated that algorithm 2 is able to solve for equilibrium states on either the fundamental path or a bifurcation path. Hence algorithm 2 is a powerful tool for nonlinear structural analysis since it is able to predict the existence of limit and bifurcation points and to determine post-buckled equilibrium states. Also addressed are the methods of formulating mathematical models for nonlinear structural analysis. A comparison of the methods of integrating the equations of motion for nonlinear dynamics problems and the selection of an appropriate time step for the time integration schemes are presented. / Master of Science

The effect of normal load, contact velocity, and dwell time on the coefficient of adhesion at slip in braking was investigated. A test rig that simulated locomotive wheel/rail interactions was used for the experimentation. The results indicated a drop in the coefficient of adhesion with increasing speed. However, normal load, contact velocity, and dwell time, as operating variables, did not have any effect on the variation of the coefficient of adhesion. A description of the investigation and recommendations for further studies is included. / Master of Science

The high cost of land in large urban centers and increasing energy costs have prompted the revival of an old method of construction. Joint occupancy is the sharing of land for different combinations of uses. There are many concerns in our cities where land costs are exorbitant and many users compete for the available ground. In the case of public schools, high construction costs, difficult and expensive credit, and even the loss of revenue when schools are removed from the tax rolls, all contribute to the taxpayers unwillingness to pay for new schools. The United States' increasing dependence on foreign oil and ever-increasing energy costs have resulted in government incentives for building insulation and the development of solar energy. There are a few larger scale projects but mostly the use of solar energy has been at the residential scale. This thesis attempts to provide one solution to a set of cumulative problems. / Master of Architecture

System engineers are currently planning satellite communications links in the 20/30 GHz bands and frequency reuse through orthogonal polarizations. This thesis examines the system level constraints imposed by medium effects at these high frequencies of which the most serious is rain induced attenuation and depolarization. The effect of crosstalk between orthogonal channels is calculated in terms of a degradation of the carrier to noise ratio. This concept is combined with the results of rain propagation modeling to define a rain induced effective attenuation which incorporates the effects of depolarization and attenuation. Methods for computing the effective attenuation and link outage times caused by rain are outlined which are applicable to any earth to space millimeter wave communication link. The Millimeter Wave Communications Experiment is used as an illustrative example of these methods. / Master of Science