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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
81

Progressive failure of slopes in lined waste impoundments

Esterhuizen, Jacob J. B. 03 August 2007 (has links)
The failure of the Kettleman Hills landfill focused attention on the uncertainties associated with the use of limit equilibrium analyses for evaluation of the stability of slopes in which failure occurs along displacement-softening interfaces. Sliding on such interfaces can occur in a progressive manner with the result that the available interface strengths are reduced below their peak values. The amount of strength reduction depends on the magnitude of shear displacement, which varies from one location to another. Because the limit equilibrium method does not provide any information regarding the magnitudes of shear displacements along the sliding interface, it can only provide realistic assessments of stability where progressive failure effects are small, or where the degree of strength reduction due to progressive failure can be estimated independently. The objective of this research study was to develop procedures to study the phenomenon of progressive failure in lined landfills, and to use the results of these studies as a basis to provide guidance for performing limit equilibrium analyses. Progressive failure along liner interfaces was analyzed using the finite element method. Adaptation and application of the finite element method for this type of analysis was a principal focus of this study. Two new plasticity models for interface behavior, a displacement-softening model and a work-softening model, were developed to simulate strength reduction along liner interfaces. The work-softening model performs better than the displacement-softening model when applied to laboratory tests performed under conditions of changing normal stress. However, the differences in performance of the two models were not significant when applied to landfills. The displacement-softening model is computationally more efficient, and it was used in most of the analyses. Progressive failure effects were severe for all the cases that were analyzed in this study. Analyses of the Kettleman Hills failure showed that the average available shearing resistance at failure was only about 10 percent higher than the residual shearing resistance. Analyses of hypothetical Municipal Solid Waste landfills indicated that the average available shearing resistance would be about 6 percent to 14 percent greater than the residual shearing resistance. This means that a limit equilibrium factor of safety of 1.4 based on residual strengths would correspond to a factor of safety of 1.5 if progressive failure was taken into account. / Ph. D.
82

A study of the procedures and their perceived effectiveness in the recruitment of African American teachers in city school divisions in Virginia

Hobbs, Betty E. 05 October 2007 (has links)
The purpose of this study was to investigate the procedures and their perceived effectiveness in the recruitment of African American teachers in city school divisions in Virginia. The research questions investigated were: (1) What are the procedures used by human resource directors in city school divisions in Virginia to recruit African American teachers? (2) To what extent are these procedures helping to increase the number and percentage of African American teachers in city school divisions in Virginia? (3) What problems do human resource directors in city school divisions in Virginia encounter in recruiting African American teachers to their divisions? (4) What strategies do human resource directors in city school divisions in Virginia use to overcome these problems? This study, both quantitative and qualitative in nature, focused on human resource directors in each of the 39 city school divisions in Virginia. The primary method of data collection was a questionnaire which consisted of forty one items. To compliment the quantitative study, three human school divisions in Virginia were interviewed by phone. Chi Square Tests of Association were used to compare the use and perceived effectiveness of recruitment practices in city school divisions in Virginia. After data were gathered and analyzed, the researcher presented the data using tables. The results of this study showed that using other employees to recruit, networking through other educators, having recruitment fairs, and sending vacancy announcements to colleges were the procedures used most often by human resource directors to recruit African American teachers. Likewise, these procedures were the most effective in helping to increase the number and percentage of African American teachers. Human resource directors reported that the most common problems they encountered when recruiting were: (1) the decreasing number of African American teachers in relation to the rising number of African American students; (2) expanding career opportunities in other fields for African Americans; (3) the pool of African American teachers not adequate to meet the needs; and (4) greater economic rewards in other fields for African Americans. The directors also reported that the most common strategies used to overcome recruitment problems were: reflecting an ethnically diverse teaching force in recruitment information; developing a strong recruitment program; and participating in career fairs at predominately black colleges and universities. Five major themes emerged as the human resource directors who were interviewed described the strategies they use to recruit African American teachers. They were: (1) promoting teaching; (2) diversifying the teaching pool; (3) improving resource directors from the city the culture of teaching; (4) developing volunteer programs for college professors and middle school students to assist in schools; and (5) increasing salaries to that of other professions. / Ed. D.
83

Exploration of session perceptions in the words of clients and therapists

Batzel, Donna 02 October 2007 (has links)
This qualitative, baseline study collected information from clients and therapists about their perceptions of their first three sessions together. Four pairs of clients and therapists, matched on gender, participated in the study. Clients were adults seeking individual therapy for problems related to relationship issues and/or depression. Each participant provided a written document of their sessions, answered questionnaires about the helpfulness of their sessions together, and participated in semi-structured interviews following each session. Written notes and questionnaires were used as a springboard for discussion during interviews. Data were analyzed qualitatively regarding their perceptions of their sessions together. Themes related to the valued contributions participants made in a collaborative, conversational dialogue as part of helpful therapy. Informed by constructivist and social constructionist principles, the methodology of this study supported a relationship with research participants that allowed them to elaborate and comment openly about their perceptions of their therapy experience. Building on previous literature that tended to rely on more close-ended, response limited opportunities, this study elicited detailed, descriptive information about perceptions of therapy by both clients and therapists. Results supported theoretical literature about therapy that is more collaborative and conversational (e.g., narrative and solution-focused) as helpful for client change. In this study, clients and therapists similarly valued aspects of therapy that supported clients in an empowered, responsible role. Meaning-making was viewed as an important part of negotiating between therapist and client to find a fit that was most help4ful for client change towards a desired goal. A "friend"-like atmosphere was appreciated in which less hierarchy and a down-to-earth and relaxed style between therapist and client was facilitated. These aspects of their experiences provided more fertile ground for change. / Ph. D.
84

Alumnae perceptions of the influence of the undergraduate experience on adult friendship and the overall quality of life

Hopkins, Carter Byrd Hunter 05 October 2007 (has links)
Recent research focuses on the importance of relationships to women's development over the lifespan. The current study of two generations of Sweet Briar College graduates looked at the perceptions of women in the classes of 1965 and 1985 about the influence of their undergraduate experience over their adult friendships. Through a survey, alumnae indicated the types and patterns of friendships they have formed and maintained as adults and ranked the importance of friendships to the total quality of their adult lives In follow-up telephone interviews with randomly selected alumnae in the two classes, both respondents and non-respondents, attributes of the Sweet Briar College undergraduate experience were examined with reference to alumnae opinions about the influence of each on the quality of the undergraduate experience. The results illustrated more similarities between the two classes than differences from the survey and from the telephone interviews. The telephone interviews helped to clarify some of the findings of the survey. Both classes reported a strong perception that friendship is an important aspect contributing to the overall quality of adult life. The two classes selected similar characteristics, purposes, and foundations of close friendships. The two classes indicated the perception that their undergraduate experience had influenced the quality of their adult lives, and the majority in both classes included at least one friend made at Sweet Briar among their current friends. Both classes stated that friends were a positive aspect of the undergraduate experience, and that friends made at Sweet Briar were integral to the way they have remember their undergraduate experience and to the ways in which they choose to relate to the College today. Data from this baseline study and others like it could prove helpful to higher education administrators in a variety of institutional settings with regard to general and specific planning around enrollment management, student development, institutional advancement, and marketing issues. / Ph. D.
85

Priorities of counseling programs and outcomes within the Virginia community college system

Collins, Susan E. 06 June 2008 (has links)
The study was designed to identify counseling services and program outcomes within the Virginia Community College System (VCCS). VCCS counseling providers and chief administrative officers (presidents and campus provosts) assessed the level of importance and existing levels of institutional priorities for counseling services and program outcomes. The study sought to clarify institutional expectations, define the role of counseling providers, and provide elements essential to the assessment of counseling program outcomes. Major findings included the identification and clarification of services provided by VCCS counseling personnel, the dichotomous relationship between the two study groups regarding recruitment and retention activities, the undervalued and under-involved role of counselor participation in research activities, the process of developing program outcomes, and the Significantly different perceptions regarding institutional priorities for services and program outcomes between the two study groups. Implications for practice were presented including the need for greater collaboration between chief administrative officers and counseling services providers to make maximum use of available resources. / Ph. D.
86

"Don't let de paddle rollers catch you": punishment, control, and resistance in the slave South

Viar, Kristin D. 25 August 2008 (has links)
This thesis explores the nature of white-slave relations in the U.S. South during the thirty-year period that preceded the Civil War. It asks one central question: How did slaveowners, overseers, patrollers, and nonslaveowners attempt to physically and psychologically punish slaves and control their behavior? An analysis of the Virginia ex-slave narratives serves as a case study of the ways white agents of authority treated slaves, and state slave codes and state supreme court cases provide information on the legal aspects of slave treatment and limits on white behavior. Additional sources that shed light on antebellum race relations include fugitive slave accounts, slave autobiographies, articles in Southern agricultural journals by owners and overseers, and white travelers’ accounts. An examination of these sources shows that slave treatment was fundamentally coercive; that the threat of violence by whites against slaves was an inseparable element of all white-slave interactions; that slave punishment and abuse was frequent and ritualized; that white and slave perceptions of slave punishment differed significantly; and that slaves influenced white behavior, refused to legitimize white authority, and actively resisted abuse. / Master of Arts
87

Investigations into the nature of architectural space

Ganapathy, Anjali 09 September 2008 (has links)
The concern of my work is primarily epistemological in nature. It is centered on the question of architectural space and the manner in which the framing of the definition of space affects architectural outcomes. This interest in definition dictated that the context of the work be theoretical as opposed to practical, universal rather than particular. This means that the particulars of an architectural work is not a primary concern and that issues such as site, programmatic concerns, economic or social issues were inconsequential in this investigation. The attempt to document this study has lead to a survey of my readings by art historians, theoreticians and philosophers on whose scholarship I relied heavily, for the theoretical principles that influenced my architectural work. The focus has been erudition and learning, that centers on process rather than on the world of temporal phenomena. At first, the architectural object was but a way to work through some of the processes, although, I realized with surprise that the work itself had gained a profound presence of its own, becoming an end in itself. / Master of Architecture
88

Characteristics of new town travel revisited: an update of the Morgan-Dickey study of Reston, Virginia

Libberton, Sean Gordon 22 August 2008 (has links)
In 1974, Kent R. Morgan and John W. Dickey published an in-depth study of the travel characteristics of new town development ("<i>The Characteristics of New Town Travel: A Case Study of Reston, Virginia</i>"). Using Reston as a case study (and Vienna, Virginia, as a "control" post WWII suburb), the objective of the Morgan-Dickey research was "to determine if the transportation element of this satellite new community has, in fact, altered the travel patterns of its residents relative to the patterns exhibited in a more traditional suburban development." The intent of the present analysis is to determine if Reston has achieved the travel patterns anticipated by Morgan-Dickey, as well as by several proponents of new town development. A review of the literature and analysis of recent travel data suggests that while Reston has exhibited significantly lower automobile availability rates than Vienna, other measures of travel behavior ---- e.g. "internal" trips and trip generation rates --- are less conclusive, with Reston exhibiting only slightly more favorable (in terms of reduced travel) patterns than Vienna. In fact, the data indicates that Reston residents are less likely to carpool, take transit, bicycle, or walk to work than Vienna workers. The research suggests that Reston may not be the most appropriate model for evaluating new towns in general. The research further suggests that development external to Reston likely has a significant impact on the travel behavior of its residents. / Master of Urban and Regional Planning
89

Modeling nitrogen transport with the ANSWERS model

Bennett, Mark R. 22 August 2008 (has links)
Nonpoint source pollution from cropland has been identified as the primary source of nitrogen and sediment, and a significant source of phosphorus in the Chesapeake Bay. These pollutants, whether from point or nonpoint sources, have been found to be the primary cause of declining water quality in the Bay. Numerous studies have indicated that, for many watersheds, a few critical areas are responsible for a disproportionate amount of the nutrient and sediment yield. Consequently, if pollution control activities are concentrated in these critical areas, then a far greater improvement in downstream water quality can be expected with limited funds. In this research a nitrogen transport model is incorporated into ANSWERS, a distributed parameter watershed model. The nitrogen model simulates nitrogen transformations of applied fertilizer and soil nitrogen in the soil. Dissolved nitrogen transport in surface runoff is modeled by assuming complete mixing of the soil surface layer and surface runoff. Sediment-bound nitrogen transport is modeled as a function of the clay content of transported sediment. The extended ANSWERS model was verified using water quality data from rainfall simulator plot studies conducted on the Prices Fork Research Farm in Blacksburg, Virginia. The four plots were 5.5 m wide by 18.3 m long with average slopes ranging from 6.2 to 11 percent. Two of the plots were tilled conventionally, and two were no-till. Simulated rainfall at an intensity of 5 cmlh was applied to the plots and runoff samples were analyzed for sediment and nitrogen. The model was then verified by comparing the simulated response with the observed data. The model predicted sediment-bound nitrogen losses within a factor of two. The model tended to overpredict dissolved nitrogen losses by a factor of five. The model shows potential as a best management practice planning tool, however, further verification of model predictions versus observed data is required. / Master of Science
90

Architecture of light and sound

Hart, Charles J. 09 September 2008 (has links)
Art reaches to our souls through the doorways of our senses. Architecture. as a form of the arts. can offer the opportunity to explore the realm of expression through an idea or intuition about perception; perception that develops at many levels and through all means of sensing what exists in the world. To discover architecture is to understand an offering of "place" as perceived through feelings of closure and openness and spatial relation and movement and many other ideas related to both architectural expression and the human experience. The realization that the success or failure of architecture lies not in the construction itself. but in how the texture of a wall gives a feeling of solidity. or the way a shadow compresses and encloses a space. or how the sound of wind blowing through a passage expresses the motion embedded in the walkway itself. is critical to the making of architecture that touches the soul. In this way. architecture is sculpture. it is poetry. it is music. it is language. and all of these are architecture. Considering the tools of light. sound. path and place and how the mind interacts with these conditions establishes the beginnings for a foundation of architectural thought. / Master of Architecture

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