Cephalomannine is a naturally occurring taxane diterpenoid closely related to the potent anticancer agent Taxol. Three aspects of its chemistry were examined. First, cephalomannine was converted to Taxol. This conversion was accomplished by the reaction of a 2'- benzoyl-7-Troc cephalomannine/Taxol mixture with oxalyl chloride to generate a common oxamic acid intermediate. Treatment of this intermediate with diphenylcarbodiimide cleaved the N-oxalyl group which resulted in a spontaneous transfer of the 2'-benzoyl group to the 3'-N position. Deprotection of the 7-Troc group afforded Taxol. Second, a number of 3'-N-acyl cephalomannine and Taxol analogs were prepared and their biological activity determined. The N-tigloyl group of cephalomannine was modified by oxygenation and halogenation to yield several cephalomannine derivatives. The Taxol analogs were prepared by coupling a protected side chain to baccatin III, deprotecting, and acylating the resulting free amine. This methodology was used to prepare several oxalyl and halogenated analogs as well as N-(phenylglyoxyl) and N-crotonyl derivatives. One derivative in particular, N-debenzoyl-N-(2"-bromopropenoyl)taxol, was found to be significantly more active than Taxol. Third, Taxotere, 10- acetyltaxotere, N-debenzoyl-N-(phenoxyacetyl)taxol, and the cephalomannine diol were synthetically prepared for testing in several tubulin polymerization systems. Earlier studies had shown that some Taxol analogs had the ability to stabilize tubulin polymers to cold, but failed to induce assembly as does Taxol. The compounds prepared were used to investigate the differences and this led to the conclusion that the hypernucleation of tubulin assembly and polymer stabilization observed with Taxol represent two distinct properties of the drug. / Ph. D.

This study details the extent to which classical scholars -- Comte, Pareto, and Durkheim -- conceptualized emotion as reflected in their respective works. This interpretive work seeks to further substantiate a classical grounding for the sociology of emotions, that is, to show that there is a breadth of material in the classical repertoire that has gone untapped by contemporary scholars of emotion, and further, that this neglected material may inform current discussions of emotions. It is clear from the review of the three theorist’s works that each maintained a conceptualization of emotion, and considered emotion to be a central concept in the discipline. Pareto’s conceptualization of emotion most clearly resembles an organismic account. Comte’s conceptualization of emotion is both an organismic and an interactive account, and Durkheim’s conceptualization of emotion most clearly resembles an interactive account. Comte’s career in particular is characterized by a shift from a theory that holds no place for emotion to a theory that is clearly dependent on the conceptualization of emotion. Each of the three theorists reviewed conceptualized emotion as a source of motivation for action. In addition, Comte and Durkheim, viewed emotion as an integral part of the process of social cohesion, as instrumental in the integration of individuals into the various institutions that comprise society. / Ph. D.

The main purpose of this dissertation is to explore and develop better signal modeling (decomposition) methods for nonstationary and/or nonlinear dynamic processes. Localization is the main focus. The characteristics of a nonstationary or nonlinear signal are decomposed onto a set of basis functions, either in the phase space spanned by time-frequency coordinates as Gabor proposed, or in the phase space spanned by a set of derivatives of different degree as defined in physics. To deal with time-varying signals, a Multiresolution Parametric Spectral Estimator (MPSE) is proposed together with its theory, techniques and applications. The resolution study provides the characteristics of windowed Fourier transforms, wavelet transforms, fixed resolution parametric spectral estimators, and the newly developed MPSE. Both the theoretical and the experimental results show that, of the above techniques, MPSE is the best in resolution. Furthermore, with proper a priori knowledge, MPSE can yield better resolution than the lower bound defined by the Heisenberg uncertainty principle. The application examples demonstrate the great potential of the MPSE method for tracking and analyzing time-varying processes. To deal with the time-varying characteristics caused by linearization of nonlinear processes, the Radial Basis Function Network (RBFN) is proposed for modeling nonlinear processes from a 'local' to a 'global' level. An equal distance sample rule is proposed for constructing the RBEN. Experiments indicate that the RBFN is a promising method for modeling deterministic chaos as well as stochastic processes, be it linear or nonlinear. The 'local' to 'global' approach of the RBEN also provides great potential for structure adaptation and knowledge accumulation. / Ph. D.

A process can be monitored for the purpose of detecting and eliminating special causes or for the purpose of adjusting the process to a target value. SPC (Statistical Process Control) methods are used for the purpose of locating and removing any unexpected changes in the quality characteristic. On the other hand, certain processes (manufacturing, chemical etc.) are monitored using APC (Automatic Process Control) methods which compensate for process variability and maintain the process as close as possible to a desired target value. The efficiency of control schemes can be increased by allowing the interval between the samples from the process to vary as a function of the process data. The following are developed for a process control problem using a variable sampling scheme: a model for the process mean, a performance criterion and an estimation technique. The process mean is a random walk model with a control variable. An observation for the process is the mean plus a random error. The Kalman filter estimation technique is used to estimate the time-varying process mean parameter of the process control problem. The objective is to determine the adjustment and sampling strategies that lead to a minimum expected loss. These adjustment and sampling limits address two questions namely, when to adjust and when to take the next sample. The performance of the VSI scheme is compared to the performance of the FSI scheme in terms of the percentage reduction in cost. Also, the effects of the cost combinations and the observation errors on the VSI and FSI are studied. / Ph. D.

Advanced, very high temperature materials that are ablation-resistant in oxidizing atmospheres are needed to withstand the severe environments found in rocket engine and aerospace vehicle applications. Boride-based coatings that form a protective layer during oxidation have been found to withstand these extreme conditions. Chemical vapor deposition has been chosen as a viable processing technique for producing these coatings. It is expected that two-phase boride coatings will have enhanced oxidation resistance over the single-phase materials by forming an oxide/glass layer to seal the base material from direct attack. Thermochemical modeling of CVD reactions was done to predict the processing conditions for the deposition of two-phase HfB₂-SiB₆ or HfB₂-SiB₄ coatings. The SOLGASMIX-PV computer program was used for these calculations, which were based on ZrCl₄, SiCl₄ BCl₃, and H₂ reactant gases. An array of temperatures (1100, 1300, and 1500K), total pressures (0.02, 0.1, and 1 atm.) and excess hydrogen concentrations (10:1, 25:1, and 50:1 H:(Zr + Si + B + Cl)) were investigated. These calculations show that two-phase HfB₂-SiB₆ and HfB₂-SiB₃ coatings are possible over a wide range of processing conditions, suggesting that a wide variety of two-phase compositions with a diverse population of microstructures can be deposited. This points to the possibility of optimizing oxidation resistance of these coatings by varying the processing conditions. A hot-wall CVD reactor was designed and constructed specifically for deposition reactions in this system. It was found to be necessary to separately deliver SiCl₄ and BCI₃ to the hot zone to prevent reactions between them and to eliminate interference with the in-situ hafnium chlorination reaction. SiB₄, rather than SiB₆, was the preferred deposition product in the Si-B-CI-H system. HfB₂ was the only compound found to deposit in the Hf-B-Cl-H system. Both borides coatings exhibited several different surface morphologies. The separate delivery of BCI₃ and SiCl₄, while necessary to prevent their gas phase reaction, caused reactant concentration gradients at the substrate surface due to poor mixing. This resulted in a variation of microstructural features across the substrate surface (both domed and faceted morphologies were deposited at the same temperatures), suggesting that reactant supersaturation is more important in determining surface morphology than temperature, pressure, and hydrogen concentration at the conditions studied. The first successful deposition of the two-phase HfB₂-SiB₄ coating was accomplished. Analysis of these two-phase coatings again reveals a broad range of microstructural characteristics, and the compositional gradients across the substrate surface also suggest the need for better gas mixing. / Ph. D.

This historical study, covering the period 1900-1989, examined how team building became a discreet educational intervention in organizations. Team building, unlike other training interventions of the 1960s, continued to be used throughout the 1980s despite the major changes in organizations. The study reveals some of the story of how people in organizations worked to develop ways to get along with each other and to improve their performance. The study is divided into three time periods. The first, 1900-1950, was a period of the discovery of the value of teams in the workplace. The second period, 1950-1969, when team building emerged, was marked by an increased focus on the social interactions of managers, supervisors and workers. The third period, 1970-1989, saw team building change its focus. During the 1970s, team building became a stand alone educational process focused on solving productivity and quality problems. The factor that most influenced the evolution and development of team building was the management theory and practice of the times. Ranging from team building focused on relationships during the era of human relations, to team building focused on problem solving for total quality management, this group learning experience continued to meet the needs for training groups in organizations. / Ed. D.

The Comprehensive Teacher Training Project (CTTP) is a distance education program developed and field tested between July 1990 and June 1992 in St. Lucia, Dominica, and St. Vincent and the Grenadines. It combined instructional modules, telephone tutorials, and periodic group instruction to help unqualified assistant teachers (UATs) pass the Caribbean Examination Council (CXC) exams in English Language, Mathematics, Integrated Science, and Social Science. To offset the high rate of attrition associated with distance education programs, student support interventions were devised to help UATs develop coping strategies and study techniques. To counteract the community’s perception that qualified teachers are insensitive subject specialists, workshops on nation building and empowerment were designed. This ethnographic study, which was conducted in St. Vincent and the Grenadines during the field testing period, sought to understand the lived experiences and perceptions of seven UATs as they matriculated through this distance education program. The study collected data through interviews, observations, and assessments of UATs, their significant others, marker/tutors (M/Ts), and country coordinator. These data were collected from UATs' communities in 1991 and during the workshops in the summers of 1990 and 1991. The study found that UATs experienced success in courses which were well written, taught what the syllabus prescribed, and what the exam tested. Those who were task-oriented, studied consistently, and community oriented, usually experienced success. M/T-initiated periodic face-to-face instructional workshops and regular telephone counseling which provided UATs with academic reinforcement and a sense of belonging. Those UATs whose significant others were supportive of their participation in the CTTP were more likely to succeed. The study also found that successful UATs adopted creative teaching techniques and active listening skills from M/Ts. Many of the lessons learned from the program were transferred to other aspects of their lives. The study concluded that Integrated Science was the most successful course and should be used as a model for the English course. UATs who felt comfortable with themselves, knew how to study, and used their time wisely usually experienced success, saw themselves as nation builders, and were perceived by the community as effective leaders. / Ed. D.

Because of the efficacy of taxol against a wide variety of cancers, the demand for this drug has vastly increased during the last decade. Due to its limited natural supply, a number of alternative sources of taxol continue to be investigated. One approach toward alleviating the taxol supply problem is by the systematic investigation of the structure-activity relationships of the molecule, in order to establish the structural features and functionalities necessary for biological activity. Research efforts during the last decade have led to the establishment of the molecular domains and functionalilties which are crucial for biological activity, however at the inception of this work, the structure-activity relationships of the C-4 position of taxol were unknown. It was thus the major goal of this work to prepare 4-deacetyltaxol, in order to assess the importance of the C-4 acetate for overall activity, as well as to have a template molecule with which to begin studies aimed at determining the effect on activity rendered by replacement of the C-4 acetate with other acyl groups. Preliminary studies of the deacylation and reacylation of baccatin III were carried out in order to find conditions necessary for the preparation of 4-deacetylbaccatin III, and hence 4-deacetyltaxol. 4-Deacetyltaxol has now been prepared from baccatin III via two synthetic approaches and from taxol via one synthetic approach, and has been shown to be significantly less potent than taxol, suggesting that the C-4 acetate is necessary for biological activity. From the investigation of several potential synthetic approaches toward the formation of 4-acyltaxol analogs, one methodology has been developed which has allowed the preparation of 4-acyltaxol derivatives from baccatin III] or the more readily available 10- deacetylbaccatin III. This particular methodology can be extended to the preparation of other 4-acvitaxol or 4-acyltaxotere derivatives. Two C-5a halogenated oxetane ring-opened compounds have been prepared from a 4-deacetyltaxol derivative, offering the opportunity to investigate the potential effects on biological activity generated by modifications to the oxetane ring. / Ph. D.

The main building of the Solitude complex is one of the oldest buildings on the campus of Virginia Polytechnic Institute and State University. The purpose of this study is to provide preliminary research for the master preservation plan of the historic landmark. In order to preserve and renovate the building, a field survey was conducted to collect data. Under the guidelines of the Historic American Building Survey, the building has been fully documented on measured drawings, and visible defects have been inspected. Computer programs were used as a means to execute drawings; a written report of the survey was organized according to the major building components. By using the knowledge of architectural history, building construction, preservation philosophy, and wood preservation technology, the collected data was analyzed, the causes of the defects were diagnosed, and the preservation treatments were suggested. Furthermore, recommendations for adaptive reuse are proposed. Meanwhile, this study also leaves openings for further study in some special fields. / Master of Science

Within a group of streets and neighborhoods and at the very fringe of the French Quarter is a boulevard named Esplanade. It is here where an attempt is made to explore particular architectural issues in the design of a hospice. Issues that have a significance both to this project and to others beyond it. An exploration that bridges between the architectural and experiential qualities of the past and present by creating a modern, architectural language that makes places that support the issues of history, surroundings, density, typology and style. / Master of Architecture