Torsional fatigue tests were conducted on 4370 steel oil quenched and tempered at 1000° F in (l) the uncharged state, (2) the hydrogen charged state, and (3) in a hydrogen environment. The tests were conducted on both smooth (K_t = l.l) and V-notch (K_t = 3.8) test specimens. A statistical analysis conducted at the 99% confidence limit for the smooth test specimens indicated that precharging with hydrogen increased the fatigue life of the material and also the fracture surface of the test specimens changed from a circumferential crack to a 45° diagonal crack. At a 90% confidence limit, charging with hydrogen did not affect the fatigue life of the V-notched specimens. At a 99% confidence limit for both the smooth and V-notched test specimens, testing in a hydrogen environment increased the fatigue life of the material. Bending fatigue tests were also conducted on the same material and the results indicated that charging with hydrogen decreased fatigue life of smooth test specimens (K_t = l.l) but increased the fatigue life for V-notched specimens (K_t = 2.4 and 3.8). / Ph. D.

In the parametric development of statistical inference it often is assumed that observations are independent and Gaussian. The Gaussian assumption sometimes is justified on appeal to central limit theory or on the grounds that certain normal theory procedures are robust. The independence assumption, usually unjustified, routinely facilitates the derivation of needed distribution theory. In this thesis a variety of standard tests for scale parameters is considered when the observations are not necessarily either Gaussian or independent. The distributions considered are the spherically symmetric vector laws, i.e. laws for which x(nx1) and Px have the same distribution for every (nxn) orthogonal matrix P, and natural extensions of these to laws of random matrices. If x has a spherical law, then the distribution of Ax + b is said to be elliptically symmetric. The class of spherically symmetric laws contains such heavy-tailed distributions as the spherical Cauchy law and other symmetric stable distributions. As such laws need not have moments, the emphasis here is on tests for scale parameters which become tests regarding dispersion parameters whenever second-order moments are defined. Using the principle of invariance it is possible to characterize the invariant tests for certain hypotheses for all elliptically symmetric distributions. The particular problems treated are tests for the equality of k scale parameters, tests for the equality of k scale matrices, tests for sphericity, tests for block diagonal structure, tests for the uncorrelatedness of two variables within a set of m variables, and tests for the hypothesis of equi-correlatedness. In all cases except the last three the null and non-null distributions of invariant statistics are shown to be unique for all elliptically symmetric laws. The usual normal-theory procedures associated with these particular testing problems thus are exactly robust, and many of their known properties extend directly to this larger class. In the last three cases, the null distributions of certain invariant statistics are unique but the non-null distributions depend on the underlying elliptically symmetric law. In testing for block diagonal structure in the case of two blocks, a monotone power property is established for the subclass of all elliptically symmetric unimodal distributions. / Ph. D.

Socio-economic, education, and health variables were examined to determine the primary causes of malnutrition in preschool Haitian children. A survey of 160 women and their child closest to weaning age was conducted in three regions of Haiti in January 1978. Ordinary least squares multiple regression analysis was used to determine the combined power of the socio-economic, education, and health variables and the relative power of each independent variable separately in explaining malnutrition in the sample population. Results showed that the amount of food or food money available had the greatest impact on the child's current nutritional status as, measured by weight/age. Long term malnutrition, as measured by height, age, was most affected by education. Health variables as a group were least effective in explaining malnutrition although the number of illnesses a child had had was highly related to malnutrition. A strong interaction between weaning age and months spent in a nutrition center suggested that children who were weaned early were more likely to become severely malnourished and required longer periods of nutritional rehabilitation than children who were weaned later. Recommendations were made to incorporate the findings into current nutrition center programs in Haiti. / Ph. D.

The purpose of this study was to determine the relationship between qualitative evaluation of community college learning resource programs, as measured by a questionnaire distributed to selected faculty and students at eighteen single-campus Virginia community colleges, and quantitative measures frequently used as comparative indicators of program quality. The questionnaire, in two almost identical versions, one for students and one for faculty, was developed from Evaluative Criteria (4th edition, 1969), published by the National Study of Secondary School Evaluation, and consisted of six groups of five questions, each group related to a single quantitative measure, plus one additional overall evaluation question. / Ed. D.

A generalized multiple-objective research and development (R & D) capital budgeting model incorporating production-allocation decisions is developed for the analysis of the spent-nuclear-fuel management problem. The generalized model is decomposed into two subproblems. First is a multiple-objective R&D capital budgeting problem and second is a multiple-objective fuel allocation problem. Goal programming is selected as an appropriate modeling technique for both generic models. The spent-nuclear-fuel-allocation problem is further decomposed into a dynamic program with a goal program at each stage. The objectives are to allocate R&D funds to process or technology development and to allocate spent fuel to certain alternatives so as to minimize the weighted and prioritized vector cost. With regard to the objectives of non-proliferation and non-diversion, occupational and population exposure, uranium resource conservation, and fuel cycle economics. the major conclusion is to use the spent fuel for further energy production, preferably via a combination of extended burnup and recycle alternatives. / Ph. D.

The purpose of this investigation was to determine the extant relationship between formal statements of attendance policy, as implemented by each school administrator. and the associated student absentee rates. Four high schools in Newport News, Virginia, each which used somewhat differing attendance policies were examined. The school which used an alternative attendance policy was compared to each of the other three schools. each of which used a variation of a traditional attendance policy. In addition, failure and dropout rates were examined to determine the relationship among the school attendance policies and these variables. A comprehensive review of the related literature revealed numerous variables which affected student attendance rates. In order to determine the comparability of the schools, it was necessary to descriptively examine and statistically test by school, selected relationships among the following variables: family income level, parental educational attainment level, the age, sex, teaching experience and educational qualifications of each school's faculty, and the sex composition and the SRA scores in reading, language arts, mathematics, social studies, science and use of sources of each school's student body. In general terms, it can be concluded that the school which used the alternative attendance policy differed in significant respects from the other three schools among many, though not all, of the dimensions measured. Due to these differences, it was not possible to single out the attendance policy specifically as the most important variable associated with actual attendance rates. It may be concluded, however, that given the demographic and educational characteristics generally associated with favorable (low) absentee rates as those present in the other schools and given the data presented in this study, the alternative attendance policy may well have been causing favorable effects, that is as a descriptive observation, the school which used the alternative attendance policy had, for reasons inexplicable save for the policy, lower than expected student absentee rates. It also may be concluded from the findings that perhaps, the use of the alternative attendance policy decreased the failure rates because more students attended more classes each day. Finally, the used alternative attendance policy did not influence the dropout rate among schools. / Ed. D.

This study showed that Extension Services, like any other human service organizations, are having difficulty in serving diverse populations where there are overlapping political jurisdictions. One example of such a situation was the interstate metropolitan region that included Washington, D.C., Maryland and Virginia. This region is one of 38 such regions in the United States. The three extension services in metropolitan Washington appear to be failing to meet the need for nutrition education, consumer education, urban horticulture, street safety, and volunteer civic leadership and other needs because they are not fully utilizing available resources and are unable to capitalize on such earmarked resources as those designated by the Office of Management and Budget Circular A-95 review process which requires areawide consultation and regional planning. An organizational model was developed as part of the study and appears to satisfy such criteriaas maximizing resource utilization and access to new resources while minimizing friction among the land grant universities and related institutions in the region. In clarifying needs and refining issues, over 50 knowledgeable consultants were. involved in the study. In developing the model and testing for feasibility the ten key actors on policy matters that would become involved in accepting and implementing the model were used as a panel of experts. They further defined needs and approaches, critiqued the preliminary models, and eventually agreed upon the proposed model presented in the study. The result of the study is "A Proposed Model for an Interstate Metropolitan Extension Service Authority for Metropolitan Washington." The model has five major elements: a proposed charter, a set of bylaws, a table of organization, a decisionmaking process, and recommendations for implementing the model are included in the study. / Ed. D.

An examination was conducted of alternative responses to the water supply situation in four cities in southeastern Virginia. Cost/benefit analyses were performed for the provision of projected levels of use and for reductions in those levels of use achieved with the use of quotas, price increases, and water saving devices. An important element of these analyses was the consideration of the costs incurred as a result of waste water treatment with different levels of water use. The levels of the principal types of water use were estimated for each city. This provided a basis for the projection of water demand curves necessary for estimating the value of water. Optimal schedules for the development of additional water sources were derived through the examination of water demand, relative to the costs of operating and expanding water supply and waste water. treatment facilities. / Ph. D.

Air drying of naturally infested soils (0.12 to 0.38% water or about -2,000 bars) resulted in no recovery of Cylindrocladium crotalariae microsclerotia, but rewetting soils to near field capacity for 1 to 4 wk before assay resulted in partial recovery from the air drying-induced decreased germinability. Numbers of germinable C. crotalariae microsclerotia (assayed at 26 C) decreased progressively over 4 wk when naturally infested soils were incubated at 6 C. No germinable microsclerotia were recovered when soils were incubated at -10 C. When soils incubated at -10 C and at 6 C were transferred to 26 C for 4 wk, the low-temperature effect was partially reversed. Incubation of naturally infested soils under field conditions over the winter months (November-February) indicated that a similar low-temperature phenomenon exists in nature. Germinability of axenic, laboratory-grown microsclerotia of C. crotalariae, C. floridanum, and C. scoparium incubated 4 wk at 6 C ranged from 0 to 91.3% (mean = 37.7%) of the initial germinability. Partial recovery of laboratory-grown microsclerotia from the lowtemperature effect, by incubation at 26 C, was demonstrated. Conductivity measurements of solutions bathing microsclerotia incubated at 6 C and 26 C for 4 wk indicated that chilling injury may account, in part, for decreased germinability of microsclerotia. Direct observation of washed conidia of C. scoparium on rewetted, non-sterile soils at 26 C indicated that peak germination (33-58%) occurred after 24 h incubation. Peak germination on continually moist soils was somewhat lower (18-26%) than on rewetted soils. Conidia did not germinate on continually moist soils at 6 C. Conidia germinated at a high level (93-95%) in axenic culture in the absence of exogenous carbon and nitrogen substrates. The inhibition of conidium germination on soils was due, in part, to the presence of fungistatic soil volatiles. Addition of low levels of carbon and nitrogen substrates nullified the inhibitory effect of soil volatiles. Germinability of C. scoparium, C. crotalariae, and C. floridanum conidia in artificially infested soils (assayed on a selective medium at 26 C) decreased progressively during incubation at 26 C from 1 wk to 4 mo. No germinable conidia were recovered after incubation of soils at 6 C for 4 wk. Control of Cylindrocladium root rot of black wainut seedlings with sodium azide at 224 kg/ha applied by the plowdown method was comparable to MC-33 at 504 kg/ha. Sodium azide at 67 kg/ha was only marginally effective in disease control. Reduction of Cylindrocladium microsclerotium populations, qualitatively assayed by the azalea leaftrap method, was found in soil samples from plots fumigated with sodium azide and MC-33. A small-spored Cylindrocladium sp. with clavate to papillate vesicles, identified as C. parvum, was consistently recovered from diseased roots and soil samples from a Virginia forest nursery. Percentage recovery from necrotic roots and soil samples collected from root zones of necrotic black walnut seedlings was appreciably higher for C. parvum than for C. floridanum or C. scoparium. In greenhouse tests, limited pathogenicity of C. parvum on black walnut seedlings was demonstrated. / Ph. D.

The purpose of this study was to identify and examine the roles and functions of parent advisory councils serving Spanish-English bilingual projects funded under ESEA Title VII. It was also the intent of this study to determine if there existed signif icant differences on the ranking of roles and functions by the participants with respect to the specified variables of: position of participant, sex, age level, education level, bilingualism and ethnicity. The roles and functions under the program areas of planning, implementation and evaluation were identified through an extensive review of the literature. Twenty-one Spanish-English bilingual projects with grades Kindergarten through eight, funded under ESEA Bilingual-Bicultural Programs 1976-1977 were randomly selected from <ul>Guide To Title VII ESEA Bilingual-Bicultural Programs 1976-1977</ul>. The participants from these bilingual projects were advisory council chairpersons, and project directors. The research instrument developed was a questionnaire which solicited from the participants demographic information on the advisory councils and also asked participants to rank, according to primacy, roles and functions under the program areas of planning, implementation and evaluation. The data were analyzed by the Kendall Coefficient of Concordance W and Multivariate Analysis. The .05 level of significance was chosen for both tests. The results indicated that there existed a high degree of agreement within each group of respondents on the ranking of roles and functions. The only exception was a low degree of agreement by chairpersons ranking functions under evaluation. The results also showed that the independent variables identified made no difference on the ranking of roles and functions. The only exception was the sex variable on the ranking of roles. Male respondents ranked the roles of advisor, supporter and director first, second and third respectively, while female respondents ranked the roles of supporter, director and advisory first, second and third respectively. / Ed. D.