Diss. de mestrado : Educação : Campinas. - Bibliogr. p. 219-224.

No description available.

Thèse--Sc. pol.--Lausanne, 1975. / Bibliogr. p. 249-262.

Diss.--Philosophische Fakultät--Saarbrücken, 1981. / Bibliogr. p. 386-393.

Ph. D.

The structure of alicyclic dicarboxylic anhydrides was found to have a significant effect on the final physical and chemical properties of a cured epoxidized novolac resin, and the final properties of a cured system can be predicted with reasonable accuracy from the theoretical structure. Properties were related to structure in terms of cyclic rings, unsaturation, substituted groups, etc. Measured properties were flexural strength, tangent modulus, toughness (area under the stress-strain curve), density, heat distortion temperature, and solvent sensitivity, as well as the retention of these properties after 250°C aging. The tensile test was substituted for the flexural test for the softer materials due to excessive slippage between supports. The anhydride structure was found to influence properties primarily through its effect on physical density, cross-linking density, inter-conformational rotations, and extent of reaction. Overall results revealed hexahydrophthalic anhydride as an excellent hardener in the as-cured state for combining high toughness with good heat distortion temperatures and solvent resistance. Succinic anhydride is a close second in toughness although adversely affected in other properties by its low extent of reaction. Aging of the materials reveals the saturated single ring anhydrides to be superior in retention of properties, although all the materials embrittle severely, with methyl endomethylene tetrahydrophthalic anhydride having the lowest property retentions due to crazing. Vinyl monomers were added to the unsaturated systems in an attempt to enhance properties by promotion of the reaction through unsaturation. These additions were found to produce no advantageous properties except viscosity reduction; an exception being the maleic anhydride cured system where the cross-linking rate was significantly increased. The branched alkenyl succinic anhydrides were investigated as "flexibilizers" for a maleic anhydride cured system and the flexural strength, tangent modulus, toughness, and heat distortion temperatures were all found to decrease with increasing mole percent branched alkenyl succinic anhydride substituted for maleic anhydride. Properties of the substituted succinic anhydride cured materials, themselves, reveal that density, tensile strength, and moduli all decrease with increasing chain length while tensile elongation and solvent sensitivity increase. Essentially the effect of increasing chain length is to decrease both physical and cross-linking density and to subsequently affect all the other properties according to their dependence on these two density factors. Substituted succinic anhydrides with methyl branched alkenyl chains produced higher strength materials with higher heat distortion temperatures than the corresponding anhydrides with linear chains. The unsaturated substituted succinic anhydrides were found to be sensitive to surface embrittlement at high temperatures resulting in lower tensile elongations and toughness when compared to their saturated counterparts. / Ph. D.

Ph.D.

The present study seeks to determine what relationships, if any, exists between types of urban residential sub-areas and social participation patterns. The study concerns a comparison of residence in two contiguous suburban areas and the relationship between them and participation in voluntary associations, in neighboring activities, and in kin visitation. The two suburban types compared are residential areas of single family dwellings and mobile home courts located in the Roanoke Standard Metropolitan Statistical Area. One hundred and twenty households were interviewed, 62 mobile home court and 58 housing settlement households. Both a structured and an unstructured interview schedule were administered. The data from the structured schedule were machine processed. Statistical tests used are the point biserial and the Pearson product moment correlations. There are three categories of dependent variables, participation in voluntary associations, participation with neighbors, and kin participation. It is hypothesized that the suburban mobile home court households are less likely to affiliate and participate in social activities outside the nuclear family than are suburban single family dwelling settlement households. The suburban housing settlement households participated more in voluntary associations, however, they did not participate more in neighboring activities or in kin participation than did the suburban mobile home court households. Using the data from the structured and the unstructured interview schedules, two composite types of the two populations are constructed. In a descriptive sense, while the two populations reside in contiguous suburban residential areas, the populations are altogether two different types. / M.S.

The purpose of this research was to examine the relationships between feminine role perception of senior college women and their mothers. The sample was comprised of 99 senior college women living in the resident halls of Virginia Polytechnic Institute and State University and 79 of their mothers. Questionnaires used in collecting data consisted of a modified version of Christensen's (1963) "Comparison of Marital Role Perceptions of Men and Women” and a personal data form; Each of four questionnaires contained 33 similar questions measuring either seniors or their mothers' perceptions of their own role or the other's role. These questionnaires investigated feminine role perception in the two main areas of dominance and submission, and division of labor. The sample was not paired, therefore, a test of significance was not feasible. An analysis of various questions was made and the .05 level of significance was approximated with .25 as the criterion for distinguishing significant differences. The senior women and their mothers differed significantly when perceiving their roles in the areas of the wife working, dominance and submission in decision making, sharing in the discipline and care of children, managing money, and responsibilities of household tasks. Traditional concepts about the wife being subordinate and the husband. dominant in decision making appears to be shifting to the more contemporary concept where young women perceive themselves more actively involved in pursuing their career, combining motherhood, engaged in decisions affecting management of the home, and division of household tasks and care of children. / M. S.

The application of incomplete relaxation and multistep concepts in the usage of steepest descent methods for the solution of simultaneous linear equations is recognized in the literature. There has been research in the area with very favorable results. Only recently, however, has there been any recognition of the fact that these concepts can be extended to unconstrained optimization problems, and by penalty formulations, also to constrained optimization problems. This holds true not only for steepest descent methods but also for any other "improving direction." In the discussion of the application of incomplete relaxation and multistep concepts to mathematical functions, very little has been accomplished in the mechanical applying of these ideas. The primary goal of this research, therefore, is to study these concepts and learn a significant amount about them. Algorithms are developed demonstrating the usage of incomplete relaxation and multistep concepts for unconstrained optimization on two directions - coordinate and gradient directions. Discussion of the performance of these methods follows in an attempt to choose some of the better ones. Ten such promising methods are selected and are applied to some complicated unconstrained functions to investigate the adaptability of these methods. Next, the application of these methods to constrained optimization is examined. Some well known constrained procedures are discussed to show how these applications can be made. A new algorithm for constrained optimization is then developed and used to solve a real world problem both to demonstrate the use of this algorithm and to show that nonlinear programming does have applications to the "real world." Finally, some areas that need further research are mentioned and discussed. The results, in general, are quite promising. For unconstrained optimization, underrelaxation yields faster convergence than did complete relaxation for all the problems examined. The difference is highly significant; but this is not startling as the same is true in the solution of simultaneous linear equations. Multistep methods are also quite efficient providing some way of efficiently determining or approximating the multistep multipliers can be obtained. In fact, an efficient multistep method is better than anyone step method for these problems. This research shows that out of the many algorithms tried only a few seem to offer the efficiency and adaptability that is needed. These methods are isolated so that their usage may be facilitated. Each of these requires its own development and to some extent stands alone. complicated unconstrained functions to investigate the adaptability of these methods. Next, the application of these methods to constrained optimization is examined. Some well known constrained procedures are discussed to show how these applications can be made. A new algorithm for constrained optimization is then developed and used to solve a real world problem both to demonstrate the use of this algorithm and to show that nonlinear programming does have applications to the "real world." Finally, some areas that need further research are mentioned and discussed. The results, in general, are quite promising. For unconstrained optimization, underrelaxation yields faster convergence than did complete relaxation for all the problems examined. The difference is highly significant; but this is not startling as the same is true in the solution of simultaneous linear equations. Multistep methods are also quite efficient providing some way of efficiently determining or approximating the multistep multipliers can be obtained. In fact, an efficient multistep method is better than anyone step method for these problems. This research shows that out of the many algorithms tried only a few seem to offer the efficiency and adaptability that is needed. These methods are isolated so that their usage may be facilitated. Each of these requires its own development and to some extent stands alone. / Ph. D.