Vector control is an essential and effective approach for controlling transmission of vector-borne diseases. However, increasing resistance to insecticide and drugs suggests that new strategies to control vector-borne diseases are needed. One possible strategy involves replacing mosquito populations with disease-resistant transgenic mosquitoes. Transposable elements (TEs) are an important component in this new strategy due to their ability to integrate exogenous DNA into chromosomes. They could potentially be useful tools in assisting the spread of disease-resistant genes in mosquito populations. This research focuses on two related subjects, TEs and their regulation. The first subject is on a Long Terminal Repeat (LTR) retrotransposon in the African malaria mosquito, Anopheles gambiae, namely Belly. The second subject focuses on the characterization of piwi genes in the dengue and yellow fever mosquito, Aedes aegypti. For the first subject we characterized Belly by identifying the two identical LTRs and one intact open reading frame. We also defined the target site duplications and boundaries of the full-length Belly element. This novel retrotransposon has nine full-length copies in the An. gambiae sequenced genome and their nucleotide similarity suggests that there has been fairly recent retrotransposon. We have shown that Belly is transcribed and translated in An. gambiae. Single LTR circles were recovered from An. gambiae cells, which is consistent with active transposition of Belly. The second subject focuses on the piwi genes of Ae. aegypti. We found nine potential piwi genes in Ae. aegypti and two in An. gambiae. Phylogenetic analysis suggests that these piwis formed two subgroups and gene duplication within each group occurred after the divergence between the two mosquito species. RT-PCR and transcriptome analysis showed Ago3 as well as all the seven tested piwi genes were expressed either in germline tissues or developing embryos. Differential expression patterns were observed. While most piwis were transcribed in the ovaries, testis, and embryos, two piwis appear to have a zygotic expression. Three piwi genes (piwi 3, piwi 4, and Ago3) were also detected in adult somatic tissues of Ae. aegypti. The expansion of the number of piwi genes in Ae. aegypti compared to An. gambiae and D. melanogaster may be correlated with a larger genome size and greater amount of TEs. The finding of piwi expression in adult somatic tissues is intriguing. It is possible that these piwi genes were expressed in the adult stem cells. It is also possible that they may be involved with anti-viral defense. Both of these hypotheses require further testing. / Master of Science

The 1990 Clean Air Act Amendment (CAAA) contains provisions that will establish new emission standards for 190 potentially hazardous air pollutant precursors (HAPPs). Studies have suggested that many of these HAPPs have the potential to be removed prior to combustion. This thesis details the findings of a bench-scale test program that was implemented to evaluate the capabilities of physical coal cleaning technologies on the removal of trace elements from coal. Test work was completed on Pittsburgh No. 8 seam coal that was processed using physical cleaning techniques (i.e., crushing, dense media separation, froth flotation, and enhanced gravity separation). The bench-scale test circuit incorporated crushing and rewashing a coarse, mid-density product with hopes that trace element rejections would improve due to greater liberation of HAPPs. The results of this investigation showed that trace elements were predominately rejected in the coarse coal portions of the processing circuit (i.e., dense media separation), and only slight improvements in rejections could be realized from crushing any portion of the coal. It was also shown that trace element rejection could be incrementally increased with minimal loss of total yield or combustible recovery when froth flotation is put in series with enhanced gravity separation. The results of the bench-scale test work, along with trace element float-sink and release analysis data, were used to develop a simulator that can predict trace element rejections from any coal processing circuit. This was achieved by applying general partition functions to trace element washability and bench-scale processing data. Simulation studies included comparing three physical coal cleaning techniques. The results of these analyses showed that although no net improvement in trace element rejection can be gained through crushing the circuit feed, there is a slight increase in product yield. Crushing a mid-density coarse coal product also showed little or no improvement in trace element rejection. / Master of Science

No description available.

Finite element models have been successfully used to analyze adhesive bonds in actual structures, but this takes a considerable amount of time and a high computational cost. The objective of this study is to develop a simple and cost-effective finite element model for adhesively bonded joints which could be used in industry. Stress and durability analyses of crack patch geometries are possible applications of this finite element model. For example, the lifetime of aging aircraft can be economically extended by the application of patches bonded over the flaws located in the wings or the fuselage. Special two and three- dimensional adhesive elements have been developed for stress and displacement analyses in adhesively bonded joints. Both the 2-D and 3-D elements are used to model the whole adhesive system: adherends and adhesive layer. In the 2-D elements, adherends are represented by Bernoulli beam elements with axial deformation and the adhesive layer by plane stress or plane strain elements. The nodes of the plane stress-strain elements that lie in the adherend-adhesive interface are rigidly linked with the nodes of the beam elements. The 3-D elements consist of shell elements that represent the adherends and solid brick elements to model the adhesive. This technique results in smaller models with faster convergence than ordinary finite element models. The resulting mesh can represent arbitrary geometries of the adhesive layer and include cracks. Since large displacements are often observed in adhesively bonded joints, geometric nonlinearity is modeled. 2-D and 3-D stress analyses of single lap joints are presented. Important 3-D effects can be appreciated. Fracture mechanics parameters are computed for both cases. A stress analysis of a crack patch geometry is presented. A numerical simulation of the debonding of the patch is also included. / Ph. D.

This thesis is an exploration of method demonstrated in a series of mechanical drawings of the elements. An investigation of methods of drawing and of how different questions can be asked through drawing. Furthermore, this thesis asks the question of place in the elements of fire, earth, and sky in the formal relationship between walls, joints, trusses. These architectural elements protect against the natural ones, forming place focused around the hearth. This thesis traces the formal relationship between the elements of architecture stemming from the German thinker Gottfried Semper's treatise on architecture, but diverges from Semper's fixation with materiality and delves into questions of form, appearance, and construction through drawing. The drawings address questions about the elements; questions about form, tectonics, and the relation of part to whole. The whole becomes a building focused on forming a place and the relation of the elements to one another. / Master of Architecture / "Throughout all phases of society the hearth formed that sacred focus around which the whole took order and shape. It is the first and most important, the moral element of architecture. Around it were grouped the three other elements: the roof, the enclosure, and the mound, the protecting negations or defenders of the Hearth's flame against the three hostile elements of nature" (Semper 102) This reading, The Four Elements of Architecture by Gottfried Semper, and this quote were the origin of my thesis, which became a series of studies of these elements as parts and their relations to one another. Through mechanical investigative drawings I explored the traits and qualities assigned to these elements by Semper and developed my own understanding of them. Each element has a tectonic quality and architectural characteristic that defines it. The tectonic quality is "different technical skills of man used to construct the elements: ceramics and afterwards metal work around the hearth, water and masonry works around the mound, carpentry around the roof and its accessories… Wickerwork was the essence of the wall" (Semper 103-104). The mound forms the base of the building connecting it to the hearth, and also joins to the hearth and raises it. The roof as a dominant element protects from above. The wall is a spatial enclosure that forms the protected space. The hearth is the central and social element of the building, protected from nature by the other elements. In addition to an investigation of each of the elements, I also had an interest in constructing a building informed by these investigations, forming a place of gathering that focused around the hearth. How would the protective elements form and appear in space, and how would the hearth form the place around it. The wall, defined as woven and enclosing, led to a series of questions regarding its form, material, and connection to the other elements. Semper's understanding of woven extends to being a dressed wall or a wall of a pattern of parts, such as brick or wood. How can variation of size, depth, and material be used to form patterns in a wall? How do hierarchies of panels, verticality, and horizontality differ from one another? How can the wall connect to the mound and emphasize the existing character of the building? The roof, defined as dominant and of carpentry, led to a series of questions regarding frames and joints. My main interest in the roof was its structure, and the interior spatial quality it provided. How can the joint and the frame inform one another? What are the qualities of trusses? What are different types of joints and how do they display themselves? How do joints form a truss and the truss form a frame? The mound, defined as earthen and meeting, was investigated in conjunction with other elements. It forms the base that protects the hearth from the earth and acts as a base to the other elements. Its original use as a structural base for houses in marsh lands is no longer prevalent and its role lessened. Semper understood this evolution, "some elements [become] more developed while others [recede] into the background" (Semper 103). The hearth, defined as central and of worked metal, led to a series of questions regarding material, form, and relation to its surroundings. The hearth acts as a single focus that forms areas of repose protected by the other elements from nature. How should it connect to the roof and the floor? Benefits of a hanging hearth versus traditional? How can it act as more by storing wood and the other tools it needs to be worked? How can it relate to other elements through material and form? As Semper stated, "some elements [become] more developed" and I found some of these progressions through my studies. One of these developments is the hearth creating areas of transition in the interior and the need to connect this transitioning to the exterior. The frame of the hearth is repeated as a threshold, forming an area of transition between the exterior and the interior. Another development is the roof and the chimney belonging to the sky. As the mound recedes from importance, the sky and its connection to the roof develops further. These boards each developed from a series of questions, and led to further questions. They ask about the part and then about the part in relation to other parts. Each question can stand on its own, but it is only when you keep asking questions that you begin to find something. Each part is its own, but when formed together it creates something new. And that was my thesis, a series of questions and the joining of parts.

This thesis studied the finite element modeling of plane wave acoustic phenomena in ducts. The study looked into finite element factors such as shape functions, mesh refinement, and element distortion. The study concluded that the higher order shape function eight-node quadrilateral element gave considerably better results than lower order shape function four-node quadrilateral element. The eight-node element converged much faster to the analytical solution than the four-node element. The average error, taking all the cases in consideration, for the four-node element was around 30 % for a mesh refinement of about 14 elements per wavelength at 100 Hz frequency. The eight-node element in the other hand had average absolute errors of less than 1% under the same conditions. This section also found that the eight-node element was substantially more resistant to solution deterioration due to element distortion than the four-node element. For example distorting the four-node element up to 60* degrees usually increased errors very rapidly to above 100 % errors. The eight-node element on the other hand usually produced errors of less than 5 % for the same level of distortion. The study showed that the type of boundary condition used had a significant effect on the solution accuracy. The study demonstrated that the effect of the natural boundary conditions was more global. Meeting this kind of boundary condition through mesh convergence produced accurate results throughout the duct. / Master of Science

The design and construction of a building presents many conditions where materials must be joined and many opportunities where the workings may be revealed. By revealing the additive process, the joining of the pieces, the connecting of the elements, and the relation of the parts to the whole, one may discover the workings and gain an understanding of the thing. It is within this understanding, this awareness of materials, that we may strengthen our connection with a place. The vehicle for studying these ideas of architecture is a public library for the town of Riner, Virginia. The building is a construction of elements; base, frame, enclosure, division, and machines. It is in how these things are put together with hierarchy, importance, truth, and honesty where one gets to architecture. / Master of Architecture

Coal preparation is widely regarded as a cost effective method for reducing the amounts of potentially hazardous air pollutant precursors (HAPPs) that occur as trace elements in the run-of-mine coals. Unfortunately, many existing coal preparation plants are inefficient in removing trace elements because of poor circuit design and inadequate liberation of coal and mineral matter. These problems are often difficult to correct in the absence of characterization data regarding the mineralogical association and washability of trace elements in run-of-mine coals. Therefore, the first step in removing the trace elements through coal preparation is to characterize the modes of association for trace elements in a coal seam. The purpose of this project was to link the occurrence of specific trace elements to the mineralogy and washability characteristics of different eastern U.S. coal seams. Detailed characterization studies were carried out using scanning electron microscopy (SEM) coupled with automated image analysis (AIA) to establish the association between different trace elements and the various components contained in coal. The first step in this analysis required the preparation of 11 different density fractions from a run-of-mine sample of 65 x 100 mesh Pittsburgh No. 8 coal. The samples were then examined using the scanning electron microscope (SEM) to establish the individual mineral constituents contained within each gravity fraction. For comparison, each gravity fraction was also carefully analyzed for trace element content by atomic adsorption spectroscopy (AA). The contribution of various mineral components to the trace element concentrations was determined in the present work using statistical procedures, i.e., individual linear regression and multiple linear regression. After completing the SEM analyses, washability (float-sink) tests were performed on three different coal seams. In this work, several size fractions from each of three different run-of-mine coals were subjected to float-sink testing and release analysis. Because of the overwhelming amount of data, statistical analyses were conducted to show the key relationships identified by this work. The data collected from this study show that trace elements are primarily associated with the mineral matter present in run-of-mine coal. The washability work also shows that the trace elements are concentrated in the heavier specific gravity classes. The characterization work shows that majority of the trace elements are associated with the ash-forming mineral matter and pyrite. The only element found to have a strong association with organic matter was beryllium. The information obtained from this work suggests that a properly designed coal preparation plant can remove substantial amounts of trace elements prior to coal combustion. / Master of Science

Thesis (Ph.D. (Afrikaans en Nederlands))--North-West University, Potchefstroom Campus, 2009.

This study attempts to highlight the novella from a practical Creative Writing point of view. The establishment of Creative Writing as a teachable university discipline in South Africa is characterised by Creative Writing tutoring in various genres. However, there are voids to be filled in tutoring the nature of a novella and the writing thereof. The objective of this investigation into the novella is to propose a practical writing and theoretical novella approach for application in tutoring Creative Writing. The concept of a genre is investigated to place the novella within the genre categorisation, followed by research of literary sources to determine the origins, nature and historical development of the novella. This background information is essential for Creative Writing students (particularly on tertiary level) to gain knowledge of the literary tradition of the novella. The classical and modern novellas enjoy attention, while confusing terminology for the novella is placed in perspective as far as possible. Some novella definitions from different periods are presented to determine the common characteristics of the novella. These characteristics are important to describe the novella as part of my novella approach. It is essential to look at densification techniques that a writer may apply in order to highlight the novella with its concentrated structure as a particular genre. The four creative elements, event, character, time and space indicated in the title of the thesis, serve as point of departure as these elements are essential in all prose types. Based on this, the creative elements cannot define the novella specifically in their own right. A deeper insight into the writing techniques that the writer may use in the application of the creative elements to obtain the compressed structure of the novella is essential. The densification techniques are discussed based on the deduced techniques in Veldslag (1965) by Karel Schoeman. A personally created new millennium novella, Die Here III, is contained in Chapter 6 as a practical application of the densification techniques and a discussion thereof. As a time and culturally bound genre the prominence of event, character, time and space are subject to changes. Some of these changes revealed in the creative elements of Veldslag and Die Here III, are shown individually according to a sliding scale for each novella. The conclusion in Chapter 7 contains a proposed practical approach to the novella that the tutor in Creative Writing may apply. The approach to the novella involves three components: densification techniques for aspirant writers, possible shifts in the prominence of the creative elements and a description of a novella that also relates to the new millennium novella. It is important to emphasise that the approach to the novella does not contain fixed rules for the writing of a successful novella. The term novel approach hopefully disbands the idea of a fixed recipe. The same applies to the description of a novella in stead of a more closed novella definition by Karel Schoeman. A personally created new millennium novella, Die Here III, is contained in Chapter 6 as a practical application of the densification techniques and a discussion thereof. As a time and culturally bound genre the prominence of event, character, time and space are subject to changes. Some of these changes revealed in the creative elements of Veldslag and Die Here III, are shown individually according to a sliding scale for each novella. The conclusion in Chapter 7 contains a proposed practical approach to the novella that the tutor in Creative Writing may apply. The approach to the novella involves three components: densification techniques for aspirant writers, possible shifts in the prominence of the creative elements and a description of a novella that also relates to the new millennium novella. It is important to emphasise that the approach to the novella does not contain fixed rules for the writing of a successful novella. The term novel approach hopefully disbands the idea of a fixed recipe. The same applies to the description of a novella in stead of a more closed novella definition. / This study attempts to highlight the novella from a practical Creative Writing point of view. The establishment of Creative Writing as a teachable university discipline in South Africa is characterised by Creative Writing tutoring in various genres. However, there are voids to be filled in tutoring the nature of a novella and the writing thereof. The objective of this investigation into the novella is to propose a practical writing and theoretical novella approach for application in tutoring Creative Writing. The concept of a genre is investigated to place the novella within the genre categorisation, followed by research of literary sources to determine the origins, nature and historical development of the novella. This background information is essential for Creative Writing students (particularly on tertiary level) to gain knowledge of the literary tradition of the novella. The classical and modern novellas enjoy attention, while confusing terminology for the novella is placed in perspective as far as possible. Some novella definitions from different periods are presented to determine the common characteristics of the novella. These characteristics are important to describe the novella as part of my novella approach. It is essential to look at densification techniques that a writer may apply in order to highlight the novella with its concentrated structure as a particular genre. The four creative elements, event, character, time and space indicated in the title of the thesis, serve as point of departure as these elements are essential in all prose types. Based on this, the creative elements cannot define the novella specifically in their own right. A deeper insight into the writing techniques that the writer may use in the application of the creative elements to obtain the compressed structure of the novella is essential. The densification techniques are discussed based on the deduced techniques in Veldslag (1965) by Karel Schoeman. A personally created new millennium novella, Die Here III, is contained in Chapter 6 as a practical application of the densification techniques and a discussion thereof. As a time and culturally bound genre the prominence of event, character, time and space are subject to changes. Some of these changes revealed in the creative elements of Veldslag and Die Here III, are shown individually according to a sliding scale for each novella. The conclusion in Chapter 7 contains a proposed practical approach to the novella that the tutor in Creative Writing may apply. The approach to the novella involves three components: densification techniques for aspirant writers, possible shifts in the prominence of the creative elements and a description of a novella that also relates to the new millennium novella. It is important to emphasise that the approach to the novella does not contain fixed rules for the writing of a successful novella. The term novel approach hopefully disbands the idea of a fixed recipe. The same applies to the description of a novella in stead of a more closed novella definition. / Thesis (Ph.D. (Afrikaans en Nederlands))--North-West University, Potchefstroom Campus, 2009.