Thesis (MTech. degree in Mechanical Engineering.)--Tshwane University of Technology, 2008.

The introduction of alternative fuels such as natural gas is likely to occur at an increasing rate. The dual-fuel concept allows these low cetane number fuels to be used in compression-ignition (CI, diesel) type engines. Most CI engine conversions have pre-mixed the alternative fuel with air in the intake manifold while retaining diesel injection into the cylinder for ignition. The advantage is that it is simple for practical adaptation; the disadvantage is that good substitution levels are only obtained at midload. A better solution is to inject both the alternative and diesel fuels directly into the cylinder. Here, the fuel in the end-zone is limited and the diesel, injected before the alternative, has only a conventional ignition delay. This improves the high-end performance. Modern, very high pressure diesel injectors have good turndown characteristics as well as better controllability. This improves low-end performance and hence offers an ideal platform for a dual-fuel system. Several systems already exist, mainly for large marine engines but also a few for smaller, truck-sized engines. For the latter, the key is to produce a combined injector to handle both fuels which has the smallest diameter possible so that installation is readily achieved. There exists the potential for much improvement. A combined gas/diesel injection system based on small, high pressure common-rail injectors has been tested for fluid characteristics. Spray properties have been examined experimentally in a test rig and modelled using CFD. The CFD package Fluent was used to model the direct-injection of natural gas and diesel oil simultaneously into an engine. These models were initially calibrated using high-speed photographic visualisation of the jets. Both shadowgraph and schlieren techniques were employed to identify the gas jet itself as well as mixing regions within the flow. Different orientations and staging of the jets with respect to each other were simulated. Salient features of the two fuel jets were studied to optimise the design of a dual-fuel injector for CI engines. Analysis of the fuel-air mixture strength during the injection allowed the ignition delay to be estimated and thus the best staging of the jets to be determined.

Life writing is always constituted of alternate versions of the self and the lived life of the self. The duplicities inherent in life writing are central to this study. These duplicities refer not only to the doubleness, but also to the constructedness, of life writing. My enabling assumption is that a life lived is never the same as the life written. Some of the questions at stake in the discourse of life writing include: How may the self be represented in literary form? How is biography a necessary ground of autobiography? What is the borderline between history and life story? Why and how is a lived life different from a written life? How much "truth" is there in life writing? One obvious starting point is to trace the history of selfhood, or the identity of the self. Charles Taylor's Sources of the Self: The Making of the Modern Identity (1989) provides a thorough analysis of the sources of the self in its historical transformation from Plato's time to our era. However, only recently have media theorists such as Eric Havelock (1963), Benedict Anderson (1991), Mark Poster (1995) and Ronald J. Deibert (1997) offered an estimate of how self-identity changes as technology varies, and how the form of communication alters the bases of identity. Based on discoveries in neuroscience, Paul Eakin (1999) uses narrative theory to explain why life writing is always made up of multiple versions and how the notion of selfhood is profoundly shaped by culture. William Spengemann's historical and philosophical analysis of traditional autobiographies helps to explain different forms of autobiography in terms of personal motives and cultural reasons for writing. This study shows that life writing is necessarily a process of translation in which facts must be transmuted into stories. In the process of translation, there are always alternate versions of the self, forms, media, voices, narratives, realities and finally alternate versions of fictions. By looking at seven of Carol Shields's fictions, this study aims to illustrate how Shields goes beyond models of historical, philosophical, and poetic self-presentation to find new ways and new forms for self-presentation in life writing. / October 2007

Despite the success of modern medicine in treating infections, infectious diseases remain a major source of morbidity and mortality worldwide. The evolution of antibiotic resistant strains of bacteria means that new innovations in therapeutics must be pursued to combat this emerging threat. A novel approach is to utilize the anti-infective properties of endogenous host defense peptides by creating smaller synthetic peptides with enhanced protective activities. Some of these peptides directly kill bacteria and many display varied immunomodulatory activities, enhancing the host innate immune response to more effectively clear an infection. Here I examined the efficacy of several synthetic peptides in a murine model of invasive bacterial infection, induced by the Gram positive bacterium Staphylococcus aureus. Several peptides were able to significantly reduce peritoneal bacterial load in vivo by up to 4-logs relative to the controls, either through direct antibacterial killing or immunomodulatory activity. The latter class was studied in more detail; in particular, the peptides IDR-1 and 1002 displayed significant immunomodulatory effects in vivo. Both peptides were able to significantly induce the proinflammatory chemokines MCP-1, RANTES and KC, as well as increased recruitment of neutrophils and monocytes to the site of infection. These effects were not dependent on live bacteria, as heat inactivated S. aureus was also able to induce chemokines and cell migration. Mice that had been depleted of macrophages did not respond to peptide treatment, indicating that macrophages are an important effector cells through which immunomodulatory peptides counter infections. These results suggest that synthetic peptides have the potential to become a viable treatment option for bacterial infections.

The literature reports controversy among teachers about the value of an alternate assessment for students with significant cognitive disabilities (SCD) (Kampfer, Horvath, Kleinert, & Kearns, 2001).The purpose of this study was to investigate the perceptions of special education teachers about the value and implementation of the Arizona Alternate Assessment (AIMS-A) for instructional planning.Twelve elementary special education teachers from three school districts in Southern Arizona were placed in one of two focus groups. They were asked questions about the value of the alternate assessment, the impact on instructional planning, the allocation of time to complete the assessment, and the usefulness of the data collected for the alternate assessment. Later, in-depth interviews were held with three of the 12 teachers representing each of the districts. The teachers' responses to the questions asked in the focus group and interview sessions were tape-recorded, transcribed, and organized into themes.Results revealed four major themes and 11 sub-themes. Most teachers valued the AIMS-A information in guiding their teaching. Some teachers, however, believed the instrument did not accurately assess students with the most severe disabilities. Teachers reported the assessment helped guide their instructional planning. The limited time allocated during the school day to complete the assessment resulted in an additional burden on teachers' personal time. Teachers found documenting and collection data throughout the school year was necessary to be able to accurately assess students during the spring testing period. Most of the teachers found the progress data useful.Six recommendations for State (SEAs) and Local Education Agencies (LEAs) resulted from the implications. The first recommendation is to acquire positive teacher perceptions and support for the AIMS-A by providing teachers with a thorough understanding of the benefits of the assessment. A second recommendation is for LEA administrators to assist teachers in finding time to administer the AIMS-A. The third recommendation is that the LEA's must provide in-service training. The fourth recommendation requires modification of existing policies when needed. The fifth recommendation is to create a state-wide data base that articulates student progress on the AIMS-A. The final recommendation is to modify existing policies where needed.

Despite the success of modern medicine in treating infections, infectious diseases remain a major source of morbidity and mortality worldwide. The evolution of antibiotic resistant strains of bacteria means that new innovations in therapeutics must be pursued to combat this emerging threat. A novel approach is to utilize the anti-infective properties of endogenous host defense peptides by creating smaller synthetic peptides with enhanced protective activities. Some of these peptides directly kill bacteria and many display varied immunomodulatory activities, enhancing the host innate immune response to more effectively clear an infection. Here I examined the efficacy of several synthetic peptides in a murine model of invasive bacterial infection, induced by the Gram positive bacterium Staphylococcus aureus. Several peptides were able to significantly reduce peritoneal bacterial load in vivo by up to 4-logs relative to the controls, either through direct antibacterial killing or immunomodulatory activity. The latter class was studied in more detail; in particular, the peptides IDR-1 and 1002 displayed significant immunomodulatory effects in vivo. Both peptides were able to significantly induce the proinflammatory chemokines MCP-1, RANTES and KC, as well as increased recruitment of neutrophils and monocytes to the site of infection. These effects were not dependent on live bacteria, as heat inactivated S. aureus was also able to induce chemokines and cell migration. Mice that had been depleted of macrophages did not respond to peptide treatment, indicating that macrophages are an important effector cells through which immunomodulatory peptides counter infections. These results suggest that synthetic peptides have the potential to become a viable treatment option for bacterial infections.

Life writing is always constituted of alternate versions of the self and the lived life of the self. The duplicities inherent in life writing are central to this study. These duplicities refer not only to the doubleness, but also to the constructedness, of life writing. My enabling assumption is that a life lived is never the same as the life written. Some of the questions at stake in the discourse of life writing include: How may the self be represented in literary form? How is biography a necessary ground of autobiography? What is the borderline between history and life story? Why and how is a lived life different from a written life? How much "truth" is there in life writing? One obvious starting point is to trace the history of selfhood, or the identity of the self. Charles Taylor's Sources of the Self: The Making of the Modern Identity (1989) provides a thorough analysis of the sources of the self in its historical transformation from Plato's time to our era. However, only recently have media theorists such as Eric Havelock (1963), Benedict Anderson (1991), Mark Poster (1995) and Ronald J. Deibert (1997) offered an estimate of how self-identity changes as technology varies, and how the form of communication alters the bases of identity. Based on discoveries in neuroscience, Paul Eakin (1999) uses narrative theory to explain why life writing is always made up of multiple versions and how the notion of selfhood is profoundly shaped by culture. William Spengemann's historical and philosophical analysis of traditional autobiographies helps to explain different forms of autobiography in terms of personal motives and cultural reasons for writing. This study shows that life writing is necessarily a process of translation in which facts must be transmuted into stories. In the process of translation, there are always alternate versions of the self, forms, media, voices, narratives, realities and finally alternate versions of fictions. By looking at seven of Carol Shields's fictions, this study aims to illustrate how Shields goes beyond models of historical, philosophical, and poetic self-presentation to find new ways and new forms for self-presentation in life writing.

Life writing is always constituted of alternate versions of the self and the lived life of the self. The duplicities inherent in life writing are central to this study. These duplicities refer not only to the doubleness, but also to the constructedness, of life writing. My enabling assumption is that a life lived is never the same as the life written. Some of the questions at stake in the discourse of life writing include: How may the self be represented in literary form? How is biography a necessary ground of autobiography? What is the borderline between history and life story? Why and how is a lived life different from a written life? How much "truth" is there in life writing? One obvious starting point is to trace the history of selfhood, or the identity of the self. Charles Taylor's Sources of the Self: The Making of the Modern Identity (1989) provides a thorough analysis of the sources of the self in its historical transformation from Plato's time to our era. However, only recently have media theorists such as Eric Havelock (1963), Benedict Anderson (1991), Mark Poster (1995) and Ronald J. Deibert (1997) offered an estimate of how self-identity changes as technology varies, and how the form of communication alters the bases of identity. Based on discoveries in neuroscience, Paul Eakin (1999) uses narrative theory to explain why life writing is always made up of multiple versions and how the notion of selfhood is profoundly shaped by culture. William Spengemann's historical and philosophical analysis of traditional autobiographies helps to explain different forms of autobiography in terms of personal motives and cultural reasons for writing. This study shows that life writing is necessarily a process of translation in which facts must be transmuted into stories. In the process of translation, there are always alternate versions of the self, forms, media, voices, narratives, realities and finally alternate versions of fictions. By looking at seven of Carol Shields's fictions, this study aims to illustrate how Shields goes beyond models of historical, philosophical, and poetic self-presentation to find new ways and new forms for self-presentation in life writing.

In FAMOUS MEN WHO NEVER LIVED, unwilling refugees from an alternate universe find their place in our New York City, making peace with what they have lost.

Orientador: José Ricardo de Arruda Miranda / Banca: Luciana Corá / Banca: Clélia Akiko Hiruma Lima / Resumo: O trato gastrintestinal (TGI) constitui um grupo de importantes atividades motoras, es-sencial à vida. Uma série de metodologias é empregada no estudo dessas atividades e das patologias a elas associadas. No entanto, estas técnicas são geralmente invasivas, requerem cirurgia, inserção do cateter, ou, para a construção de um modelo temporal destas funções, demandam o sacrifício de uma série de animais na obtenção dos dados necessários. A Biosusceptometria de Corrente Alternada (BAC) é uma técnica biomagnética de baixo custo, portá-til, não-invasiva, livre de radiação ionizante, que pode ser utilizada para avaliar as proprieda-des do TGI pelo monitoramento da posição e concentração de materiais ferromagnéticos, usa-dos como marcadores magnéticos. O objetivo desta dissertação foi, através de um sistema BAC associado a marcadores magnéticos, apresentar uma nova forma de analisar propriedades do trato gastrintestinal, co-mo o esvaziamento gástrico e tempo de trânsito gastrointestinal, de alimentos sólidos e líqui-dos em modelos animais de pequeno porte. Um sistema dedicado foi construído para analisar estas propriedades. A instrumenta-ção consiste em dois pares de bobinas, um de referência e outro para a detecção. Cada par é composto por uma bobina de excitação e uma detecção. Uma linha de base fixa separa os pa-res de detecção e referência, e funciona também como suporte para a instrumenta-ção. Também é importante ressaltar que as bobinas de detecção são dispostas em uma confi-guração gradiométrica. Seu princípio de funcionamento baseia-se em um transformador de fluxo magnético, que o par (excitação e detecção), localizado mais distante da amostra magnética funciona co-mo uma referência para o sistema. Assim, quando se aproxima um material magnético... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The gastrointestinal tract (GIT) motor activities constitute an important group, essen-tial to life. A series of methodologies is employed in the study of these activities and its asso-ciated pathologies. However, these techniques are generally invasive, require surgery, catheter insertion or, in the temporal model construction issue, require the sacrifice of a series of ani-mals to record the necessary data. The Biosusceptometry of Alternate Current (BAC) is a low cost biomagnetic technique, portable, non-invasive and radiation free, which can be used to evaluate GIT properties by monitoring position and concentration of ferromagnetic materials when used as magnetic markers. The objective of this dissertation was to present a new way to measure GIT properties like gastric emptying and gastrointestinal transit time of both solid and liquid food in small animal models, using the BAC system associated with magnetic markers. A dedicated biosusceptometry system was constructed to analyze these particular properties. The instrumentation is constituted of two coil pairs, one for reference and another for detection. Each pair consists of an excitation coil and a detection one. A fixed baseline separates the detection and reference pairs, and works also as support to the instrumentation. It is also important to point that the detection coils are arranged in a gradiometric connection. Its working principle is based on a magnetic flux transformer, which the pair (excita-tion and detection) located farther from the sample works as a reference. Thus, when ap-proaching a magnetic material to the sensor, the balance created between the two faces of the sensor will be broken. This imbalance can be measured, digitalized and acquired. The mag-netic tracer used in the liquid transit determination was a commercial... (Complete abstract, click electronic access below) / Doutor