Dissertations / Theses on the topic 'Metalli non ferrosi'

A liga de alumínio designada AA4006 é muito utilizada na indústria. É uma liga do sistema Al-Fe-Si, com teores (% em massa) de Si na faixa de 0,8 a 1,2% e Fe entre 0,5 e 0,8%. Apesar de ser bastante utilizada, ela foi pouco estudada. Neste trabalho foi realizado um estudo comparativo da microestrutura e da textura cristalográfica entre chapas da liga AA4006 produzidas por dois processos industriais de lingotamento: contínuo (Twin roll caster TRC) e semicontínuo (Direct chill DC). Para a caracterização microestrutural, foram utilizadas as técnicas de microscopia óptica com luz polarizada, microscopia eletrônica de varredura com microanálise química, medidas de condutividade elétrica e ensaios de dureza Brinell. A textura cristalográfica foi determinada por difração de raios X. Foram detectadas e discutidas diferenças significativas nas morfologias e distribuições de grãos e de partículas de fases intermetálicas. O estudo da textura cristalográfica foi realizado ao longo da espessura das tiras e os resultados mostraram variações significativas da textura entre as chapas ao longo da espessura. A chapa produzida por lingotamento contínuo apresentou uma típica textura de cisalhamento nas proximidades de sua superfície, enquanto nas regiões mais internas a fibra foi observada. O estudo da recristalização de chapas metálicas laminadas a frio é muito útil para a obtenção da temperatura de amolecimento do material submetido a um tratamento térmico. Tratamentos térmicos isócronos no intervalo de uma hora foram feitos em amostras das duas chapas e a chapa produzida pelo processo TRC apresentou a temperatura para 50% de recristalização em torno de 290 ºC e a amostra da chapa produzida pelo processo DC em torno de 270 ºC. A textura cristalográfica pode mudar com a recristalização e com a laminação do metal. Utilizando estas etapas de processamento do material, a orientação dos grãos de uma tira metálica pode ser otimizada, a fim de, por exemplo, melhorar a estampabilidade de chapas na obtenção de um dado produto com valor agregado. Neste trabalho as curvas de amolecimento para duas chapas produzidas por lingotamento contínuo e lingotamento semicontínuo da liga de alumínio AA4006 também foram determinadas e comparadas. Embora as diferenças detectadas entre as curvas de amolecimento tenham sido pequenas, foi possível verificar que a recristalização da chapa produzida por twin roll caster TRC ocorre em temperaturas mais elevadas do que na chapa produzida pelo processo direct chill DC. Resultados da textura cristalográfica em amostras destas chapas (laminadas e recozidas) foram obtidos utilizando difração de raios X e difração de elétrons retroespalhados EBSD. Estes resultados indicaram a presença da textura de cisalhamento na superfície e a fibra no centro da amostra laminada a frio (70% de redução) da chapa obtida por lingotamento contínuo. Na amostra da chapa obtida por lingotamento semicontínuo, a componente cubo e a fibra foram vistas na superfície e no centro. Uma textura fraca com grãos orientados ao acaso foi vista nas duas amostras (TRC e DC) recristalizadas das duas chapas, possivelmente, devido à nucleação estimulada por partículas. A fibra desapareceu nas amostras (TRC e DC) recristalizadas.
AA4006 Aluminum alloy is extensively used in industry. It belongs to the Al-Fe-Si system, with Si between 0,8 and 1,2 % mass, and Fe between 0,5 and 0,8 % mass. This alloy is less studied despite its extensive use. A comparative microstructural study has been performed in as-received AA4006 alloy strip produced by two industrial casting processes: twin roll caster (TRC) and direct chill (DC). Polarized optical microscopy, scanning electron microscopy with microanalysis, electrical conductivity measurements and Brinnel hardness tests have been used for microstructural characterization. Significant differences in the grain and intermetallic particle sizes, morphologies and distributions were detected and are discussed. Thermal treatments effects on the silicon content in solid solution were also studied. Crystallographic textures have been also determined. Textures across thickness of both sheets have been analyzed and compared. Results showed significant texture changes across thickness of the specimens. Texture analysis was carried out using X-ray diffraction technique. Twin roll caster (TRC) sheet presented the typical shear texture near the surface, while, in internal regions, the -fibre was observed. A recrystallization study of cold rolled metallic sheets is very important to obtain softening temperature for the material during annealing. After cold rolling with 70% of reduction in thickness, followed by isochronous heat treatments, the samples of the two sheets produced by TRC and DC presented a 50% recrystallization temperature around 290 ºC and 270 ºC, respectively. Crystallographic texture can change during the metal rolling and recrystallization. These processing steps can optimize the grain orientation distribution in a metal strip to improve, for instance, the stamping process, in order to obtain an aggregated value product. Softening curves were also compared and determined for the two sheets (rolled and annealed) of the AA4006 aluminum alloy produced by twin roll caster TRC and direct chill DC processes. It was detected that the recrystallization of the strip produced by TRC process occurs at a higher temperature than that for the DC process, despite the little differences in their softening curves. Crystallographic texture results, for the sheet samples, were obtained by using X-ray diffraction and electron back scatter diffraction EBSD techniques. These results indicated the shear texture presence on the surface and fiber at the center of the cold rolled (70% area reduction) sample for the sheet produced by TRC process. In the sheet sample produced by the DC process, under the same conditions, the cube component and fiber texture (at the surface and at the center) were observed. A texture with random oriented grains was detected in two deformed and recrystallized samples of the two sheets (TRC and DC). It is suggested that this texture occurs due to the particle stimulated nucleation. There was fiber absence in the recrystallized samples (TRC and DC).

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
This thesis was motivated by the study of voids and non-metallic inclusions influence on the high cycle fatigue of ferrous materials like steel, powder metal and gray cast iron. A second objective was to obtain simpler parameters, like the ones measured in hardness, static bending or axial tests, to evaluate materials in early phases of projects, in a way to avoid long fatigue tests. Initially the average fatigue strength was obtained for a high carbon steel. The effect of a silicon oxide inclusion near the surface on the performance of heavy-duty Cr-Si spring wire was also analyzed. The evaluation was done in terms of stress concentrating on the inclusion contours, due to the shot peening application on the surface and normal fluctuating loads. Mechanical properties of powder metal and cast iron were revised. Static tests without and with the presence of notches were performed, with the objective of obtaining a static notch sensitivity factor, to correlate with torsion fatigue results. The relation between hardness and torsion fatigue strength was evaluated for the cast iron, and simulations using linear elastic and nonlinear materials were performed to obtain geometric stress concentrating factors. A mesoscale simulation was done in plane stress, making it possible to evaluate local stress concentration in the cast iron matrix.
Esta tese foi motivada pelo estudo da influência de vazios e inclusões não metálicas na fadiga de alto ciclo de materiais ferrosos como aços, materiais obtidos por metalurgia do pó e ferros fundidos cinzentos. Foi objetivo também, avaliar parâmetros de medição mais simples, como os obtidos de ensaios de dureza e de flexão ou tração estáticos, como forma de avaliar materiais em fases iniciais de projeto, evitando-se longos ensaios de fadiga. Inicialmente obteve-se a resistência à fadiga de alto ciclo de um aço de alto teor de carbono. Analisou-se também o efeito da presença de uma inclusão de óxido de silício próximo à superfície de um arame de aço Cr-Si utilizado em molas submetidas a cargas reversas. A análise foi feita em termos de concentração de tensão nos contornos da inclusão, devido à aplicação de shot peening na superfície e também devido às cargas de operação. Uma revisão de propriedades mecânicas de aços obtidos por metalurgia do pó e do ferro fundido foi realizada, assim como ensaios estáticos sem e com entalhe, no intuito de obter um fator de sensibilidade ao entalhe estático, como forma de correlacionar com a sensibilidade ao entalhe na fadiga em torção. Foi avaliada a relação entre a dureza do ferro fundido e a sua resistência à fadiga na torção e realizadas simulações com material linear elástico e não linear para obter um fator de concentração de tensão geométrico. Uma simulação em mesoescala em estado plano de tensão foi realizada, podendo-se determinar a concentração de tensões locais na matriz do ferro fundido.

In the first part of this thesis the prices of six non-ferrous metals (aluminum, copper, lead, nickel, tin, and zinc) are used to assess the forecasting performance of GARCH models. We find that the forecasting performances of GARCH, EGARCH, and TGARCH models are similar. However, we suggest the use of the GARCH model because it is more parsimonious and has a slightly better statistical performance than the other two. In the second part, the prices of six non-ferrous metals and the price of crude oil are used to examine the dynamic links between oil and metal returns by using the BEKK specification of the multivariate GARCH model and the Granger causality-in-variance tests. Results of our study agree with the previous studies in that the crude oil market volatility leads all non-ferrous metal markets. In order to move as far away from the effects of 9/11, daily data for the period December 12, 2003 &ndash
December 15, 2008 is used for the data analysis part of the thesis.

The aim of this thesis has been to investigate and interpret late Iron Ageand Early Medieval traces of non-ferrous metalworking on the islandGotland, Sweden. Gotland was not, based on the archaeological record, anintegrated part of the common Scandinavian culture. Instead a local,endemic cultural expression had developed; a seclusion which lasted forcenturies despite the islands central position in the Baltic Sea. In thepast, key elements for the understanding of local settlement- and burialpractices as well as the local material culture were mainly recovered andreported by local farmers. A specific category of such finds – so-called‘bronze slag’ is discussed and partly reinterpreted in the first study ofthis thesis. Two further studies treat different aspects of metalworkingand metalworkers – one discusses common archaeological notions ofScandinavian workshops, production sites and metalworkers from a criticalperspective while the other mainly focuses on the Gotlandic finds frommetal-detector surveys carried out over the last 35 years. Based on whereand to which extent, both from a quantitative and a qualitative point ofview, these finds occur a hierarchical classification into four sub groupsis presented – ordinary farm sites with traces of non-ferrous metalworking,workshop sites, potential workshop sites and last, extrovert harboursettlements. A fourth study presents an attempt to evaluate the usefulnessof magnetometry in delimiting extant traces of high-temperature crafts,such as metalworking. The last study of the thesis presents an attempt touse trace elements analysis of skeletal lead in human bone to identifypotential non-ferrous metalworkers. As the wearing of endemic Gotlandic jewellery appears to have been centralin the manifestation of the local identity it is argued that themetalworking artisans played a crucial role in defining how this identitywas signalled and displayed via the jewellery and dress-related metalobjects. It is further suggested that these artisans might have played animportant role in upholding the local economy before the advent of localminting.

At the time of the doctoral defense, the following paper was unpublished and had a status as follows: Paper 5: Manuscript.

Розрізнення кольорових металів між собою за допомогою металоаналізаторів є дуже актуальним питанням, оскільки звичайні металошукачі не вирішують дане питання. Провівши серію дослідів, автору вдалось визначити, що інформативні параметри в сигналі металоаналізатора залежать від тривалості часової реалізації вхідного сигналу, яка, у свою чергу, залежить від швидкості проходу антени над дослідним зразком, яка повинна бути завжди однаковою. Щоб правильно набрати статистичні дані для вирішення задачі розпізнавання методом лінійного передбачення, усі отримані сигнали потрібно масштабувати таким чином, щоб вони мали однакову тривалість.

Thesis (M.F.A.)--East Tennessee State University, 2003.
Title from electronic submission form. ETSU ETD database URN: etd-0330103-135724. Includes bibliographical references. Also available via Internet at the UMI web site.

The diploma thesis discusses laser cutting of non-ferrous metals using fiber YbYag laser and evaluation of the roughness of cutting edge samples. To manufacture samples of aluminium Al 99,5, deoxidized copper Cu – DHP and brass CuZn37 were used combinations of process parameters according to Taguchi statistical method. Samples were subsequently evaluated, according to the ČSN EN ISO 9013 standard and sorted into roughness cathegories, and by technical and economical evaluation, the most economical process parameter combinations were found. Experimantal part is preceded by description of general methods of cutting, description of laser types, process parameters and their influence on the occurrence of the cutting edge defects and description of roughness measurement and standard ČSN EN ISO 9013.

The thesis is focused on the theoretical description of the technology of anodizing of aluminium, magnesium, zinc and their alloys. In this work, methods for formation of oxide layers and the used chemical processes are described in detail. The experimental part of this work deals with formation of oxide layers on aluminium, magnesium and zinc of high purity under different conditions. Oxide layers of different thicknesses were created on all three experimental materials. Aluminium was anodized in a bath of 10% H2SO4, magnesium in the bath of 1 mol/dm3 NaOH, and zinc in the bath of 0.5 mol/dm3 NaOH. Processes were carried out at laboratory temperature. On the aluminium, continuous oxide layer was formed. Furthermore rule "312" was verified, that can indicatively be used for calculating the thickness of the resulting oxide layer on the aluminium. When using lower current of 0.08 and 0.2 A for magnesium anodizing, dark colored layer was created comparing to higher current of 0.5 A. More rough appearance of the oxide layer was produced with increasing voltage. Further, it was observed for magnesium that the resulting layer comprises of two sublayers. For zinc, black colored layer was created when the voltage 20 V and current from 0.4 to 0.5 A were used. In the layer, two sublayers were also observed. For lower voltage and current (0.05 A, 0.17 V), formation of the oxide layer on the zinc does not occur, but the crystallographic etching was observed.

ВКР (магистерская диссертация) состоит из введения, трех глав, заключения, библиографического списка, включающего 62 наименования. Работа включает 10 таблиц и 13 рисунков. Общий объем ВКР (магистерской диссертации) – 85 страниц. Ключевые слова: торговля цветными металлами, международные отношения, развитие торговли. Цель магистерской диссертации – исследование, оценка и анализ состояния российско-китайской торговли цветными металлами, выявление проблем и перспектив развития. исследование современного состояния российско-китайской торговли цветными металлами и разработать методические рекомендации к ее развитию Научные и практические результаты - оценено современное состояние и динамика развития российско-китайских внешнеторговых отношений - выявлены специфические особенности внешнеторговых отношений - предложены потенциальные направления дальнейшего развития российско-китайской торговли цветными металлами. Предложенные в работе меры по решению существующих в российско-китайской торговле цветными металлами проблем позволят перейти на новый этап развития. Дальнейшее развитие двусторонних отношений между Китаем и Россией имеют широкие перспективы долгосрочного и тесного взаимовыгодного сотрудничества.
The WRC (master's thesis) consists of an introduction, three chapters, a conclusion, a bibliographic list, including 62 titles. The work includes 10 tables and 13 figures. The total volume of the FQP (master's thesis) is 85 pages. Key words: non-ferrous metals trade, international relations, trade development. The purpose of the master's thesis is to research, assess and analyze the state of the Russian-Chinese trade in non-ferrous metals, to identify problems and development prospects. study of the current state of the Russian-Chinese trade in non-ferrous metals and develop guidelines for its development. Scientific and practical results: assessed the current state and dynamics of the development of Russian-Chinese foreign trade relations; revealed the specific features of foreign trade relations; potential directions of further development of the Russian-Chinese trade in non-ferrous metals have been proposed. The measures proposed in the work to solve the problems existing in the Russian-Chinese trade in non-ferrous metals will make it possible to move to a new stage of development. Further development of bilateral relations between China and Russia has broad prospects for long-term and close mutually beneficial cooperation.

A des dates et à des vitesses différentes selon les pays, l’aluminium a changé tout à la fois le monde industriel et les modes de vie. Au début du XXème siècle, le monde en développement était déjà partagé entre l’Amérique du Nord où acier et béton commençaient à façonner les villes reliées par le chemin de fer, et l’Europe où il fallait détruire pour reconstruire et où le changement a pris plus de temps. Aluminium et hydroélectricité ont effectué leurs débuts ensemble, ouvrant une longue période de croissance que leur complémentarité a accélérée. Les réussites techniques dans les deux domaines ont eu un effet boule de neige. L’expansion a duré ¾ de siècle jusqu’à ce que l’augmentation des usages domestiques de l’électricité contraigne la production d’aluminium à trouver de nouvelles sources de courant, au sein des États-Unis d’abord. Les pays en développement ont adopté le chemin suivi auparavant et assuré la continuité. Depuis 2003, la Chine est le premier producteur mondial d’aluminium. La modernisation a touché tous les domaines en même temps, sant apparaître des besoins considérables d’accompagnement. L’économie et la gestion ont construit et développé des bases théoriques et pratiques en réseau, amplifiant l’efficacité des progrès techniques. Ce qu’il a paru intéressant de mettre en lumière dans cette étude, ce sont les interactions durables entre la théorie économique et la production industrielle d’un métal qui a façonné le siècle
At different times and speeds, depending on the countries concerned, aluminium has transformed both the world of industry and our ways of life. In the early 20th century, the developing world was already divided between North America, where steel and concrete were beginning to shape cities linked by railroads, and Europe, where it was necessary to demolish before rebuilding, and the transformation therefore took longer. Aluminium and hydroelectricity emerged together, heralding a long period of growth that was accelerated by their complementarity. Technical progress in both domains had a snowball effect. The expansion lasted three-quarters of a century, until the rising household demand for electricity forced aluminium producers to look for new sources of energy, firstly in the United States. The developing countries followed the same path and provided continuity. China has been the leading aluminium producer in the world since 2003. Modernisation affected both domains at the same time, creating considerable needs for support. Economics and management sciences have developed theoretical and practical foundations in a network, amplifying the effectiveness of technical advances. The interest of this study lies in our revelation of the lasting interactions between economic theory and industrial production

Современные условия хозяйственной деятельности, ее динамика делают рационализацию процессов материально-технического обеспечения одним из основных конкурентных преимуществ хозяйствующих субъектов. Данное положение особенно актуально для материалоемких малых предприятий занятых в цветной металлургии. Целью магистерской диссертации является разработка методики обеспечения малых промышленных предприятий ломом цветных металлов. В работе анализируются основные производственные особенности малых промышленных предприятий в разрезе этапов ресурсного обеспечения предприятий, даются рекомендация по оптимизации ресурсного обеспечения малого промышленного предприятия ломом цветных металлов. Отмечено особое значение рынка вторичных металлов, как потенциального источника экономии ресурсов для материалоемких малых промышленных предприятий. В качестве источников использовалась учебно-методическая и научно-исследовательская литература, результаты исследований автора. В магистерской диссертации была разработана методика обеспечения малых промышленных предприятий ломом цветных металлов, в основу которой положен учет специфики хозяйственной деятельности, возможностей производства, оценки поставщиков и факторе времени, что позволяет снизить затраты на основные материалы, а также сосредоточить внимание на возможных точках развития вертикальной (обратной) интеграции, тем самым перейти на качественно новую основу ресурсного обеспечения.
Modern conditions of economic activity, its dynamics make the rationalization of the processes of material and technical support one of the main competitive advantages of economic entities. This provision is especially relevant for material-intensive small enterprises engaged in non-ferrous metallurgy. The aim of the master's thesis is to develop a methodology for providing small industrial enterprises with non-ferrous scrap. The paper analyzes the main production features of small industrial enterprises in the context of the stages of resource provision of enterprises, gives a recommendation for optimizing the resource provision of a small industrial enterprise with non-ferrous scrap. The special importance of the secondary metals market as a potential source of resource saving for material-intensive small industrial enterprises is noted. Educational-methodical and research literature, the results of the author's research were used as sources. In the master's thesis, a methodology was developed for providing small industrial enterprises with non-ferrous scrap, which is based on taking into account the specifics of economic activity, production capabilities, assessing suppliers and the time factor, which allows reducing the cost of basic materials, as well as focusing on possible points of development of vertical (reverse) integration, thereby moving to a qualitatively new basis of resource provision.

Les Pyrénées centrales font l’objet, depuis plusieurs décennies, de recherches pluridisciplinaires consacrées aux exploitations minières et métallurgiques médiévales. Dans l’ancienne vicomté de Couserans, les fouilles archéologiques ont permis de mettre au jour le site de Castel-Minier qui s’avère être un témoin majeur des activités d’extraction des minerais et des métaux entre la fin du XIIIe siècle et le XVe siècle. Le mobilier archéologique révèle la vocation polymétallique de l’atelier qui se caractérise par la pratique de plusieurs métallurgies qui concernent l’argent, le cuivre et ses alliages et le plomb. Notre travail a pour objectifs d’une part, d’identifier la nature et l’origine des ressources minérales qui approvisionnent le site et d’autre part, de comprendre l’organisation fonctionnelle des différents espaces de travail à travers la restitution des chaînes opératoires.Nos recherches sont conduites dans une perspective pluridisciplinaire qui associe l’étude des sources écrites et iconographiques, les résultats des fouilles archéologiques mais également les données issues des analyses achéométriques du mobilier. Les résultats obtenus mettent en évidence, outre la transformation de la galène argentifère pour en extraire l’argent, une production de plomb désargenté, de cuivre non allié et de bronze au plomb antimonié, ou caldarium. Chaque chaîne opératoire fait l’objet d’une étude détaillée où sont discutées les pratiques techniques mais également les formes et les qualités des productions. L’association de plusieurs activités métallurgiques dans les ateliers de Castel-Minier est l’occasion d’aborder la question de la polyvalence et de l’expertise des ouvriers mais également de discuter leur capacité d’adaptation suivant les opportunités minières et les attentes du marché des métaux
For several decades, the central Pyrenees have been the subject of multidisciplinary researches, which deal with medieval mining and metallurgical activities. In the ancient viscounty of Couserans, archaeological excavations unearthed the site of Castel-Minier, which played a major role in mining and metals production between the late 13th and 15th centuries. The artefacts uncovered have highlighted the polymetallic activities of the workshop, which is characterized by the practice of several metallurgies concerning silver, copper and its alloys and lead. Our work aims, on the one hand, to identify the nature and origin of the mineral resources that supply the site and, on the other hand, to understand the functional organisation of the different workspaces through the restitution of the chaînes opératoires.Our research is carried out in a multidisciplinary perspective, combining the study of textual and iconographic sources, the results of archaeological excavations and data from the archaeometric studies of the metallurgical artefacts. The results show, besides the transformation of argentiferous galena to extract silver, the production of desilvered lead, unalloyed copper and antimony-lead bronze, or caldarium. Each chaîne opératoire is subject to a detailed study in which technical practices are discussed, as well as the forms and qualities of production. The association of several metallurgical activities in Castel-Minier workshops is an opportunity to address the issue of workers' multi-skilling and expertise, and also to discuss their adaptability according to the mining opportunities and the expectations of the metals market

This essay is an analysis of the objects made of bronze found in an excavation Västergarn parish, Gotland, in 2010, conducted by the University of Gotland. The studied material presented in this essay comes from contexts inside, as well as nearby the foundation of a medieval building which purpose is still not certain. The first purpose of this study is to present the bronze-objects found inside and nearby the foundation of house 6, and to see if there are any datable objects. There is also a discussion whether there has been any bronze-crafting in the area. The second purpose is to make a contextual analysis to see if there are any differences between the material found outside and inside of the building, and what conclusions can be made regarding the function and use of the building. A spatial analysis has also been made to distinguish any patterns of the distribution of material inside and around the house.The result of this essay is partly a presentation of the material, but also that there has occurred some bronze-crafting in the form of cutting metal sheets inside or near the foundation treated in this essay. There is no evidence for casting bronze near the house foundation.The frequency of finds from outside the foundation compared to the frequency of finds within the foundation is nearly quadruple, which is to be expected since there probably has been a wooden floor inside the house to prevent all but the tiniest objects from falling through. Objects that landed on the floor were cleaned out, just to land near the entrance of the building. The finds from within the building much resembles the finds from outside the building, and the distribution-patterns of the trench indicates that the entrance to the building probably was located near the north-west corner or near the south-east corner.Hopefully, this study contributes another piece to the great puzzle that is Västergarn.

English, Zulu and Northern Sotho summaries
This study aims to evaluate the Non-Ferrous Metals Crime Combating Committee's impact on combating copper cable theft in South Africa. Data was collected via in-depth interviews with awaiting trial detainees charged with copper cable theft at the Pollsmoor Correctional Centre in the Western Cape; members of the Mpumalanga and Gauteng Provincial Non-Ferrous Metals Crime Combating Committee; members of Business Against Crime South Africa; and investigators attached to Combined Private Investigations who investigate copper theft nationally. The in-depth interviews provided a comprehensive understanding of participant experiences relating to the impact of the Non-Ferrous Metals Crime Combating Committee on the combating of copper cable theft in South Africa. Moreover, the researcher performed a thorough literature study of the phenomenon locally and internationally. Research findings indicate shortcomings in the Non-Ferrous Metals Crime Combating Committee's effectiveness, limiting its impact on preventing copper cable theft. Based on these findings, the study recommends that the Non-Ferrous Metals Crime Combating Committee be replaced with a specialised South African Police Service Non-Ferrous Metals Theft Unit. Consequently, this study puts forward a set of recommendations proposing a systematic pro-active plan to address and minimise copper cable theft in South Africa. The proposed plan convincingly presents practical solutions to minimise copper cable theft and contributes to the current body of scholarship on copper cable theft in South Africa.
Inhloso yalolu cwaningo ukuhlola umthelela wohlelo lwe-Non-Ferrous Metals Crime Combating Committee mayelana nokuqedwa kokutshontshwa kwentambo yogesi (copper cable). Idatha iqoqwe ngokusebenzisa izinhlolovo ezijulile ezenziwa ngokusebenzisa iziboshwa eziboshelwe izintambo zikagesi ezisamele ukugwetshwa ejele lase Pollsmoor Correctional Centre ngaseNtshonalanga Kapa, amalunga eMpumalanga and Gauteng Provincial Non-Ferrous Metals Crime Combating Committee, amalunga eBusiness Against Crime South Africa kanye nabaphenyi abahambisana nophiko lweCombined Private Investigations oluphenya ukutshontshwa kwezintambo zikagesi ezweni lonke. Lezi zinhlolovo ezijulile zinikeze ulwazi olubanzi lwabadlalindima olumayelana nomthelela weNon-Ferrous Metals Crime Combating Committee mayelana nokuqedwa kokutshontshwa kwezintambo zikagesi. Ngaphezu kwalokho, umcwaningi wenze ucwaningo olunzulu lombhalo wobuciko mayelana nokutshontshwa kwezintambo zikagesi lapha ekhaya kanye nasemhlabeni wonke jikelele. Ulwazi olutholakele lukhombisa iziqi ezikhinyabeza ukusebenza kahle kweKomithi mayelana nokuvimbela umthelela walo mayelana nokutshontshwa kwezintambo zikagesi. Ngezizathu ezisuselwa phezu kwalolu lwazi, lolu cwaningo lubeka phambili isethi lezincomo ezinganceda iKomiti ekuqiniseni umthintela walo ngokuhlongoza uhlelo olugqugquzelayo lokunciphisa izinga lokutshontshwa kwezintambo zikagesi eNingizimu Afrika. Lolu hlelo oluhlongoziwe ngaphandle kokungabaza lwethula izixazululo ezenzeka empilweni yangempela ukunciphisa ukwetshiwa kwezintambo zikagesi kanti lokhu kunegalelo kwiziko lamanje futhi luqhubekisa iziko lamanje lwezifundo esimayelana nokwetshiwa kwezintambo zikagesi.
Maikemisetso a thutelo ye ke go lekola khuetso ya Komiti ya Twantsho ya Bosenyi bja Dimetale tse di Sego tsa Tshipi ka ga go lwantsha kutso ya megala ya koporo. Datha e kgobokeditswe ka mokgwa wa ditherisano tse di tseneletsego tseo di sepeditswego le mahodu a megala ya koporo ao a golegilwego ao a letetsego go sekiswa Senthareng ya Tshokollo ya Pollsmoor go la Kapa Bodikela, maloko a Diprofense tsa Mpumalanga le Gauteng a Komiti ya Twantsho ya Bosenyi bja Dimetale tse di sego tsa Tshipi, maloko a Dikgwebo tsa Kgahlanong le Bosenyi tsa Afrika Borwa le banyakisisi bao ba dirisanago le Dinyakisiso tsa Praebete tse Kopantswego tseo di nyakisisago kutso ya koporo kemong ya bosetshaba. Ditherisano tse di tseneletsego tse di file kwesiso ka botlalo ya maitemogelo a batseakarolo ye e sepelelanago le khuetso ya Komiti ya Twantsho ya Bosenyi bja Dimetale tse di sego tsa Tshipi ka ga go lwantsha kutso ya megala ya koporo. Gape, monyakisisi o dirile thutelo ya dingwalo ka botebo ya kutso ya megala ya koporo tikologong ya leagong le kemong ya boditshabatshaba. Dikhwetso tsa dinyakisiso di supa mafokodi ao a lebanego bokgoni bja Komiti tshitisong ya khuetso ya yona go kutso ya megala ya koporo. Go ya ka dikhwetso tse, thutelo ye e hlagisa sehlopha sa dikeletso tseo di ka thusago Komiti go tswetsa khuetso ya yona pele ka go sisinya leano la go itokisetsa seemo se ka diregago ka mokgwa wo o beakantswego go fokotsa kutso ya megala ya koporo ka Afrika Borwa. Leano leo le sisintswego le hlagisa ka mo go kgodisago ditharollo tse di ka phethagatswago go fokotsa kutso ya megala ya koporo ka gona la ba la seabe go le go tswetsa pele popego ya bjale ya borutegi ka ga kutso ya megala ya koporo.
Criminology and Security Science
Ph. D. (Criminal Justice)

The threat posed by non-ferrous metal theft to industries in South Africa is substantial but is also regarded with indifference. A reason for this view may be that the criminal act is ordinarily not accompanied by violence and the target of the crime is an object that is far removed from the vicinity of the majority of South Africans. Non-ferrous metal theft may sometimes even be erroneously termed a victimless crime. This study endeavours to shed light on the complexities of non-ferrous metal theft and the industrial dangers that may be suffered if this crime is not eradicated. A case study from the mining industry was used to examine the nature and extent of non-ferrous metal theft. A mixed methods approach was followed in terms of which qualitative and quantitative research was done sequentially to provide the best possible representation of the situation. The participant allowed access to data over a six-year period as well as access to mine employees for interviews to assist with understanding the safety and security measures that the mine put in place to protect its workforce. This information led to another realisation, namely that if non-ferrous metal thieves cut an electricity supply line that is critical for life support and transportation in the mine, mineworkers may succumb to the harsh conditions underground. It also became evident that the police and the criminal justice system must develop a better understanding of the seriousness of non-ferrous metal theft. If this does not happen in the near future, managing the consequences of nonferrous metal theft at South African mines will become a mammoth task. Such mines and other industries affected by non-ferrous metal related theft must collaborate with each other and the police in order to understand the nature of the crime and to ensure that the prosecution of the perpetrators is handled properly. These industries should also subscribe to a pragmatic approach to crime prevention whereby various components from different crime prevention strategies are used to address the issues being experienced and whereby a unique crime prevention model for each industry and mining site can be developed.
Police Practice
M.A. (Policing)

The objective of this diploma thesis is to describe nowadays almost forgotten events in France during the Second World War, when the historical statues and monuments from the Third Republic in France are irretrievably destroyed because of melting non-ferrous metals used for arms-production in Nazi Germany. The key goal of the thesis is to mention some of the main decisions that led to the destruction of certain works and on the basis of that analysis consider to what extent the occupier contributed to their loss and to what extent their removal was inevitable. Within historical context, the first chapter introduces the period and ideas of the Third Republic until the arrival of the Vichy régime with its new ideals. The second chapter mentions expansion of sculpture of the Third Republic and statuomania. The development of the campaign for collection of non-ferrous metals and its actors are discussed in the third chapter. Afterwards this work presents specific decisions about the destruction of statues, based on religious, political and aesthetic subtext. In the fifth chapter in practical part, the thesis tries to analyze these decisions and to determine the cause of the elimination of statues based on the decisions. The last part focuses on the different generals reactions to destruction of the...

Climate change is a subject of deep distress in today’s world. Over dependence on hydrocarbon has resulted in serious environmental problems. Rising sea level, global warming and ozone layer depletion are the mainstream of any discuss world over. The collective goal of cutting carbon emission by the year 2020has prompted the search for clean, alternative energy sources. This effort are already yielding good reward as other forms of energy such as solar, wind, nuclear and hydro have received huge investment and renew interest over the past decade. Thermoelectric materials over the past decades have been tipped to replace conventional means of power generations as these materials have the ability to convert heat to electrical energy and vice versa. They are simple, have no moving parts and use no greenhouse gases. But the major drawback of these materials is their low conversion efficiency. Hence there is a need to enhance the efficiency of thermoelectric material to fulfill their undeniable potentials. A parameter called the thermoelectric figure of merit, ZT defines the efficiency of a thermoelectric material. ZT relates three non-mutually exclusive transport properties namely Seebeck coefficient, electrical conductivity and thermal conductivity. Efficient thermoelectric material should possess high Seebeck coefficient, high electrical conductivity and low thermal conductivity. Hence, one of the interesting ideas in the area of thermoelectric research is the concept of designing a bulk material with high density of phonon scattering centers so has to reduce the lattice contribution to thermal conductivity but at the same time have minimum impact oncharge carriers. This is usually achieved by utilizing interphase and grain boundaries which are localized defects to scatter phonons. The volume fraction of the grain/interphase boundaries can be control through phase modification and microstructure design. This thesis is centered on Bi-Sb-Te systems which are the present room temperature state of the earth thermoelectric material. The investigation revolves around developing a new kind of microstructure in the well-studied Bi-Sb-Te system that shows tremendous potential as a means to reduce lattice contribution to thermal conductivity. The idea of having both p and n-type thermoelectric material preferably from the same material was also a motivation in our investigation. The thesis isdivided into six chapters. The first chapter introduces the concept of thermoelectricity i.e. the direct conversion of thermal energy into electricity. The physics involved and contribution of individual to the science of thermoelectricity were enumerated. Efficiency, optimization and material selection for better thermoelectric performance were briefly enumerated. Prospective materials that are currently been investigated for better thermoelectric properties were also mentioned. The structure of the Bi-Sb-Te system which is the focus of this thesis is present in this chapter including doping effect on the thermoelectric performance of the system as well as the various methods present been employed to improve the thermoelectric properties of the system. Finally the chapter enumerates the scope and object of the present thesis. The different experimental procedures adopted in the present thesis arediscussed in chapter 2. The details of different processing routes followed to synthesize flame-melted ingots, flame-melted + low temperature milled (cryo milling) + spark plasma sintering (SPS) alloy and flame-melted + melt spinning + spark plasma sintering (SPS) alloy, are discussed followed by the various structural and functional characterization techniques. The unique advantage of the spark plasma sintering techniques over the conventional sintering method was talked out in detail. The structural characterizations performed on the synthesized alloys include XRD, SEM and whilethe functional characterizations comprised of Hall measurement, Seebeck coefficient, electrical resistivity and thermal conductivity measurements. Thermoelectric properties of selected composition of Bi-Sb-Te synthesized via flame-melting are presented in chapter 3.Detail study of four analyzed compositions namelyBi24Sb20Te56, Bi20Sb12Te69, Bi16Sb5Te79 and Bi29Sb11Te60resulted in four unique microstructure and different volume fraction of primary and secondary phases. The resultant morphologies of the microstructure were observed to have influence the thermoelectric behavior corresponding to each composition. The sole influence of anti-structural defects on the conductivity type and the role of microstructure morphologies and length scale were understood in this chapter. Samples with segregated Te and a solid solution BiSbTe3(eutectic morphology) form an n-type thermoelectric material while samples with only solid solution BiSbTe3 forms a p-type thermoelectric material. Pair of n-type and p-type material was obtained without the introduction of external dopant.The pair shows good compatibility factorsuitable for thermoelectric device. In chapter 4, the thermoelectric properties of four selected composition of Bi-Sb-Te synthesized via low temperature milling plus spark plasma sintering is addressed. The analyzed compositions are as follows Bi24Sb20Te56, Bi18Sb11Te71, Bi17Sb6Te77, and Bi28Sb15Te57 respectively. The effect of low temperature milling combine with the prospect of minimum grain growth of spark plasma sintering on the thermoelectric properties of the selected compositions were determined. Samples with eutectic morphology which would otherwise scatter charge carriers were observed to have the highest carrier mobility as a result of high volume fraction of Te phase which serves as a donor injecting excess electrons into the system. The impact of small grain size was observed on the transport properties of the sample Bi28Sb15Te57 with the highest electrical resistivity, the best Seebeck coefficient and the lowest thermal conductivity. Pair of n-type and p-type material was obtained without the introduction of external doping elements. The pairshows good compatibility factor suitable for segmented thermoelectric device. Chapter 5 narrates the thermoelectric properties of four compositions namely Bi30Sb13Te58, Bi23Sb13Te65, Bi18Sb5Te77 and Bi23Sb20Te58subjected to melt spinning plus spark plasma sintering.High cooling rate obtained during melt spinning process was observed in this chapter to cause a shift of composition which resulted in a microstructure morphology with eutectic colonies that is predominantly Te rich. These Te rich colonies in the sample Bi30Sb13Te58 was observed to change the conductivity type of the sample from an otherwise p-type to n-type while also aiding bipolar conduction which was detrimental to the overall thermoelectric performance of the alloy. Segregated Te in the form of eutectic morphology helps to inject excess electron into the bulk of the sample Bi23Sb13Te65 and Bi18Sb5Te77hereby increases the observed electrical conductivity which by virtue of the microstructure morphology is expected to be low. As a result of the processing routes, all four compositions in this chapter shown-type conductivity. Chapter 6 presents the summary of the important conclusions drawn from this work.

This dissertation focuses on the phenomenon of copper cable theft within the Gauteng Province of South Africa. Data was collected from literature sources as well as from security professionals combating copper theft. There are five primary objectives in this research: 1. To explore and to describe the extent and the impact of copper cable theft. 2. To gain insight into the profile and the modus operandi of the offender. 3. To evaluate current intervention measures used to combat the copper cable theft. 4. To describe the general factors limiting the success of combating copper cable theft. 5. To recommend probable intervention measures with which to combat copper cable theft. Semi-structured interviews were conducted with responsible security officials of victim stakeholder groups in Gauteng. It was established that copper cable theft is currently a very serious crime that deserves both attention and quick intervention before it does irreparable damage to the utility infrastructure of Gauteng, in particular, and in fact to all these infrastructures in South Africa.
Criminology
M.A. (Criminology)

This study sought to examine the significance of modus operandi information in the investigation of copper theft. Data was collected by means of a literature study and individual semi-structured interviews conducted with detectives at the SAPS Philippi East, in the Nyanga policing cluster, in the Western Cape, to promote knowledge and understanding of the significance of modus operandi information in copper theft investigations. A comprehensive literature study, concerning the dynamics of modus operandi information in forensic investigation and copper theft in South Africa, was conducted. From the results of this research, it appears that participants do realize the significance of modus operandi information in the investigation of copper theft. It is, however, evident that they do not optimally utilize modus operandi information regarding copper thieves as a result of limited experience, case docket overload, and the inaccessibility of available data – all of which inhibit the establishment of modus operandi information pertaining to copper thieves. Role-players in the copper theft investigation sphere isolate themselves from each other and do not share the available modus operandi information amongst each other; these results in a non-systematic integrated approach to copper theft investigation. The study identifies the challenges and shortcomings, experienced by detectives at SAPS Philippi East, which inhibit the optimal utilization of modus operandi information in the investigation of copper theft. The study then puts forward a set of recommendations that could assist the SAPS, the relevant parastatals and other role-players in enhancing the utilization of such information.
Criminology and Security Science
M. Tech. (Forensic Investigation)