<p>Aluminum alloys are widely used in many manufacturing areas due to good castability, lightness and mechanical properties. The purpose of this research is to investigate copper’s influence on an Al-Si-Mg alloy (A356). Copper in the range of 0.6 – 1.6 wt. % has been used in an A356 aluminum based alloy. In this work a simulation of three different casting processes, sand-, die- and high pressure die-casting has been employed with the help of gradient solidification equipment. The microstructure of the samples has been studied by optical and scanning electron microscopy. Materials in both as-cast and heat treated states have been investigated through tensile test bars  to get the mechanical properties of the different conditions.</p><p> </p><p>Questions that have been subjected to answer are what influence does copper have on the plastic deformation and on fracture behavior and whether there is a relationship between the content of copper and increased porosity or not; and in that case explore this relationship  between the amount of copper and the mechanical behaviour.</p><p> </p><p>It has been analyzed that a peak of mechanical properties is obtained with a content about 1.6 wt. % copper. The increment of copper seems to have a remarkable impact on the mechanical properties and especially after the aging process showing a large raise on the ultimate tensile strength and yield strength.</p><p>Relationship between the copper content and increased porosity could not be found.</p>

No abstract available. / Thesis (LL.M.)-University of KwaZulu-Natal, Durban, 2008.

The Constitution of the Republic of South Africa6 (hereinafter the Constitution) gives everyone the right to fair labour practices.7 The Labour Relations Act8 (hereinafter the LRA) regulates the relationship between employers and employees as well as the relationship between employers and trade unions. These labour relations are quite extensively regulated by statutory measures. The same can unfortunately not be said about the relationship between a trade union and its members. Because a trade union is a legal entity, a trade union is controlled and managed by certain functionaries like any body corporate. The management structures of the trade union are defined in the trade union’s constitution. A trade union can not perform any legal functions which are not provided for in the trade union’s constitution. 9 The trade union’s constitution states the nature of the relationship between the union and its members.10 Workers join trade unions in order to protect themselves and their rights in the workplace. An expectation is therefore cultivated by the members that the trade union, through its representative power and mandate to act on behalf of the members, will do so in the best interest of the members. The disruption of the relationship can have negative implications for the trade union. In this study, relevant case law will be sited to explain the contents of the legal responsibility of a trade union to its members. The specific focus of the study is the legal responsibility of a trade union if its members would suffer pecuniary loss or harm as a result of the trade union’s actions. The purpose of this study is to discuss the regulation of the relationship between a trade union and its members in South Africa and to find a solution for the fragmented regulation or non-regulation thereof. The authority that a member grants to a trade union, mostly in the form of a contract, involves the expression of the will of the members that the trade union has the necessary power to perform judicial acts on its behalf. The discussion is limited to the actual authorization originated by a contract of mandate between a trade union and its members. In terms of the common law’s contract of mandate a representative is obliged to perform his orders with care and diligence, convey information, to act in good faith and to account for his actions. There are no statutory measures that regulate the nature of the legal relationship between a trade union and its members provided for in the trade union’s constitution. This study discusses the regulatory challenges that the regulation of the relationship between a trade union and its members in South Africa are facing, and some recommendations are made with regards to the possible application of existing legislation and the common law contract of mandate. / LLM (Labour Law), North-West University, Potchefstroom Campus, 2014

The feasibility of using oriented polymer technology in the design and manufacture of mechanical power transmission belts has been investigated. Working from an initial selection of polymers a die-drawing technique for orienting the polymers was devised, and the static and dynamic mechanical properties of the oriented polymers were investigated. These results indicated that PP, PBT, PPS and PEEK were suitable for further research. Of these 4 materials PBT was selected as the most appropriate material for belt manufacture based on cost, processability (drawing temperature, natural draw ratio) and limitations of laboratory equipment. A technique based on free-tensile drawing combined with simultaneous rotational motion was designed and used to manufacture oriented PBT flat belts from cylindrical injection moulded preforms. The technique used a tensile machine with two pulley-clamps, a fitted heated chamber and an electric motor to provide rotational motion to the belt during drawing. Two types of oriented PBT flat belts with different cross sections were produced successfully, termed 'thick' and 'thin'. These belts were tested on a purpose-built rig comprising two equal diameter pulleys, one driven by an electric motor and the other connected to a generator to provide load. The belt life and power transmission performance was investigated at various conditions of speed, transmitted torque and tension, and the results indicated that despite their smaller cross section 'thin' flat belts demonstrated up to 3 times longer life. However life was only 100hours, which was very low compared with conventional flat belts that last for many thousands of hours at higher speeds and much greater power transmission capacity. Synchronous belts were then produced through the same manufacturing method used for flat belts. This aspect of the research concentrated on the initial pitch design and size, i.e. the timing. Initially a rectangular tooth profile was selected for its simplicity in terms of manufacture. The produced belts exhibited high pitch length variation as well as deformed teeth and were not usable for synchronous power transmission. An extra timing feature was included to control orientation; reducing the pitch length variation enabling consistent tooth production. It was observed that the areas between the extra timing feature and the tooth edges did not orient completely with some regions remaining undrawn. Finite Element Analysis (FEA) was used to predict the drawing behaviour of different shapes and dimensions of the timing features. The results suggested that a 4mm wide and 7mm long slot provided the highest possible extension and the minimum non-oriented regions on the groove. Whilst, the thickness and width of the drawn belt timing features showed differences to the FEA predictions, manufactured synchronous belts based on that design had much better controlled dimensions and the lowest achieved pitch length variation ( ±1%), compared to initial attempts. It is concluded that oriented polymers have the potential to be used in power transmission belts since they offer higher stiffness, tensile strength and creep resistance compared with isotropic polymers that are currently used in commercially available belts such as thermoplastic polyurethane (TPU) and polyvinyl chloride (PVC). The main disadvantages were the lack of dimensional stability and number of cycle to failure.

Well-logging and aerospace applications require electronics capable of withstanding elevated temperature operation. A key element of high temperature packaging technology is the Si die attach material, and a comparative study of two die attach systems for use in harsh environment has been performed. Die bond sample packages, using commercial adhesives and an Au-Si eutectic solder, have been manufactured and were subsequently thermally exposed for various times at 250 and 300°C respectively. The adhesive die bond packages comprised a high temperature co-fired ceramic (HTCC) substrate with W, Ni and Au metallisations whereas the Au-Si die bond packages used thick film Au metallised on a Al₂O₃ substrate. Optimisation of the eutectic die bonding parameters was successfully performed for the Au-Si system by an experimental design method, which improved mean and spread of maximum bonded areas and consequently, the shear load to failure. Bonded area was systematically assessed by scanning acoustic microscopy (SAM) followed by digital image analysis (DIA). Accelerated testing comprised thermal cycling and thermal shock and although showing some degradation, Au-2wt%Si die bonds were surprisingly robust, showing excellent subsequent stability during industrial device testing investigations.

Automotive companies are actively pursuing to increase the use of high-strength-lightweight alloys such as aluminum, magnesium, and advanced/ultra high-strength steels (A/UHSS) in body panel and structural part applications to achieve fuel efficiency while satisfying several environmental and safety concerns. A/UHSS sheet materials with higher strength and crashworthiness capabilities, in comparison to mild steel alloys, are considered as a near-term (i.e., ~5 years) choice of material for body and structural components due to their relatively low cost when compared with other lightweight materials such as aluminum and magnesium. However, A/UHSS materials present an increased level of die wear and springback in stamping operations when compared to the currently used mild steel alloys due to their higher surface hardness and high yield strength levels. In order to prevent the excessive wear effect in stamping dies, various countermeasures have been proposed such as alternative coatings, modified surface enhancements in addition to the use of newer die materials including cast, cold work tool, and powder metallurgical tool steels. In this study, a new die wear test method was developed and tested to provide a cost-effective solution for evaluating various combinations of newly developed die materials, coatings and surfaces accurately and rapidly. A new slider type of test system was developed to replicate the actual stamping conditions including the contact pressure state, sliding velocity level and continuous and fresh contact pairs (blank-die surfaces). Several alternative die materials in coated or uncoated conditions were tested against different AHSS sheet blanks under varying load, sliding velocity circumstances. Prior to and after wear tests, several measurements and tribological examinations were performed to obtain a quantified performance evaluation using commonly adapted wear models. Analyses showed that (1) the rapid wear method is feasible and results in reasonable wear assessments, (2) uncoated die materials are prone to expose severe form wear (galling, scoring, etc.) problems; (3) coated samples are unlikely to experience such excessive wear problems, as expected; (4) almost all of the the recently developed die materials (DC 53, Vancron 40, Vanadis 4) performed better when compared to conventional tool steel material AISI D2, and (5) in terms of coating type, die materials coated with thermal diffusion (TD) and chemical vapor deposition (CVD) coatings performed relatively better compared to other tested coating types; (6) It was seen that wear resistance correlated with substrate hardness.

This thesis examines how Ernst Ludwig Kirchner reconceived the female nude within the two contexts of Expressionism and the German nudist movement. In particular, it looks to Kirchner’s early paintings, executed between 1909 and 1914, of female nudes in landscape settings to determine how Kirchner operated within and departed from the conventions of the female nude. This thesis challenges the feminist critique of Expressionist painting and Kirchner’s female nudes. It also examines how Kirchner’s female nudes in landscapes are complicated by the early twentieth-century development of German nudism. While these paintings are often categorized as bathers following nineteenth-century French precedent, they in fact are unique products of die Brücke philosophy.

The aim of this study is to compare selected episodes of Ovid's Metamorphoses with three works of modern literature containing the theme of metamorphosis, and to follow their intertextual relations, dependency and innovation of Ovidian themes. On the basis of a comparison of the ancient and the modern text it is examined which motives remain constant during centuries and which, on the contrary, are evolving and shifting their meanings. Through the perspective of the Metamorphoses an attempt is made to interpret the works from a less usual angle. The most significant Ovidian characters that are examined in this study are Teiresias, Daphne, Hyacinth, Orpheus, Ceres, Icarus, Callisto and Io.

Le polissage mécano-chimique (CMP) en raison de spécifications sévères, telles que l‘aplanissement de la surface à ± 5 nm, est devenu un enjeu crucial pour le développement des nœuds technologiques 14 nm et au-delà. Les méthodes actuelles de caractérisation de la topographie, limitées en termes de taille de surface analysée, évaluent l'efficacité des procédés sur des structures nommées boites de mesure. Ces structures mesurent 100 µm x 50 µm et sont situées entre les circuits intégrés. Elles sont donc non représentatives de la topographie de la puce et, de ce fait, des procédés de métrologie topographique de la puce sont requis. Dans un premier temps, nous montrons que la microscopie interférométrique est capable de caractériser la nano-topographie sur des distances centimétriques avec une résolution latérale micrométrique. La caractérisation par microscopie interférométrique de la nano-topographie induite par les procédés de CMP montre que les méthodes actuelles fournissent des valeurs topographiques non représentatives de la puce. Une méthodologie associée à ce nouveau type de caractérisation est proposée et discutée. Dans un deuxième temps, nous montrons que la diffusion de la lumière permet un contrôle rapide (trois minutes par plaques) et non destructif de variations nanométriques de la topographie de grilles de quelques dizaines de nanomètres de large sur toute la plaque. / Chemical Mechanical Polishing (CMP), because of narrower specifications, as surface planarization at ± 5 nm, is becoming a critical process for the development of the 14 nm technology node and beyond. Habitual topographic characterization techniques, limited in acquisition area, appraise processes efficiency through structures called test boxes. Those structures have a size equal to 100 µm by 50 µm and they are located, in the scribe lines, between the chips. Consequently, they are not representative of the die level topography and die level topographic metrology processes are required. In a first time, we show that interferometric microscopy is able to characterize nano-topography over centimetric distances with micrometric lateral resolution. Interferometric microscopy characterization of CMP processes induced nano-topography demonstrates that usual methods provide non representative die level topography values. A new characterization kind related methodology is proposed and discussed. In a second time, we show that diffused light measurement allows fast (three minutes/wafer) and non-destructive control of gate nano-topography variations for pattern widths of some tenths of nanometer.

The purpose this study was to explore the relationship between counseling mental health practitioners’ attitudes toward euthanasia and their ethical decision making levels when confronted with clients facing end-of-life concerns. A review of literature indicated a series of complex ethical, moral, and societal issues surrounding clients’ right-to-die issues. Because of the lack of research in the counseling field and the growing prevalence of right-to-die issues with clients who have a diagnosis of a terminal illness, more research in the counseling field is needed (Hadjistavropoulos, 1996; Winograd, 2012). Participants for the present study were recruited from six state divisions of the American Counseling Association; Alabama, Louisiana, North Dakota, Maryland, Vermont, and Utah. Two multiple regressions were conducted in addition to one correlation and one MANOVA. One multiple regression was conducted using EDMS-R ans the dependent variable and one multiple regression was conducted using ATE overall score as the dependent variable. The Independent variables used were years in practice, gender, state, and religion. The dependent variables used were participant EDMS-R score and participant ATE score. Variables were chosen to examine variability accounted for in ATE and EDMS-R participant scores. Findings from this small study indicated that counselors’ years in practice, gender, state, and religion accounted for more of the variability in their beliefs about euthanasia (13.5) than their ethical decision making levels (2.7). Also, counselors’ religion had the greatest effect on participants’ ATE overall scores and on their EDMS-R P index scores. Counselors’ ATE overall scores as well as their both active and passive scores were all shown to be correlated to their P index scores with their ATE active scores exhibiting the strongest correlation and their ATE passive score exhibiting the weakest correlation. Future research suggestions include assessing counselors’ religion in more depth, and focusing on the other demographic variables in the study, as well as conducting an initial qualitative study to provide insight from individual participants as opposed to assessing a large group of participants.