A Thesis submitted to the Faculty of Science, University of the Witwatersrand, in fulfilment of the requirement for the degree of Doctor of Philosophy. Johannesburg March 2016 / This study aims to provide a comprehensive description of the Flora, biogeography and diversity of the serpentine outcrops of Barberton Greenstone Belt in Mpumalanga, South Africa in order to set conservation priorities for these areas. About 30 large and many smaller serpentine outcrops form part of the Barberton Greenstone Belt and consist of various combinations of serpentinized minerals. Seven outcrops were selected to be studied in detail. A floristic analysis recorded 744 species and subspecies, 319 genera and 94 families. The flora includes 33 taxa endemic to serpentine soils and six taxa, which are hyperaccumulators of nickel. The endemic taxa make up 41 % of the endemics of the Barberton Centre of Endemism. The serpentine flora was found to be different to the surrounding non-serpentine vegetation in terms of numbers of species per family, the ratios of dicotyledons to monocotyledons and familial composition. The Asteraceae and the Anacardiaceae support a higher number of endemics than expected, which suggests genetic pre-adaptation within these families and specifically within the genera Berkheya, Helichrysum and Ozoroa. Most of the endemic taxa exhibit long-range dispersal suggesting gene flow between populations on different outcrops. The endemics represent a mix of neo-endemics and paleoendemics. Non-parametric species richness estimators used to predict the species richness of each site, indicated that five serpentine outcrops have higher species richness than the surrounding non-serpentine areas. Indices of diversity calculated showed similar patterns to those of the species richness estimates. The Barberton Greenstone Belt serpentine outcrops show relatively high plant diversity when compared to some other serpentine outcrops around the world. Beta diversity calculated for each site was not correlated with altitude and weakly correlated with the size of outcrops. Species turnover between outcrops is high and is positively correlated with the geographical distance between outcrops. Diversity at higher taxonomic levels were calculated, and results suggest that genera have some potential for facilitating the ranking of outcrops in terms of biological richness to select sites for conservation planning. Less than 30% of serpentine outcrops are adequately conserved. Species and genus richness and endemism were used to select five outcrops that have high conservation priority / MT2016

Os custos de produção de minério de ferro possuem variações de acordo com a especificidade de cada mina. Na fase mina, dois dos maiores custos de produção estão associados aos índices: distância média de transporte e a relação estéril minério. A implantação do projeto de múltiplas minas e correias transportadoras em Itabira visa diminuir os custos associados a estes dois indicadores. O método de alimentação da planta de beneficiamento oriundo de múltiplas minas foca em reduzir a relação estéril minério global do complexo e a implantação de correias transportadoras mitiga o aumento da distância média de transporte. O presente trabalho tem seu enfoque em uma proposta de lavra de múltiplas minas e de uma pilha de minério para alimentação de três diferentes usinas. Propõem-se um modelo de programação linear por metas que determinará a melhor alimentação das usinas, menor distância média de transporte e menor relação estéril minério. Este modelo de otimização foi elaborado utilizando o software LINGO com interface com EXCEL, e avalia cenários diversificados entre o transporte por caminhões fora de estrada e o transporte misto entre caminhões fora de estrada e transportadores de correia de longa distância. Os resultados apresentados mostram que o método de múltiplas minas é uma saída técnica e economicamente viável para melhor aproveitamento das jazidas do Complexo Minerador de Itabira, apresentando uma economia que varia de US$82M até US$118M dependendo do local de instalação das unidades de Britagem Semimóvel (BSMs). / Production costs of iron ore varies according to the specificity of each mine. In the mining phase, some of the largest operational costs are associated to the haulage distance and the stripping ratio. In this context, the implementation of the multiple mines project and the conveyor belts at the Itabira Complex Mines aims to optimize these two indicators. The multiple mines methodology focuses on reducing the overall stripping ratio of the complex, and the implementation of conveyor belts mitigates the increase of the haulage distance. Two mines and a stock pile are available to feed three different concentration plants. The goal is to achieve the best way to feed the plants considering the economic aspects. A linear goal programming model is proposed to determine the best iron ore mass feeding the plants from different mines, taking into account the least haulage distance and the smallest stripping ratio. This optimization model was developed using LINGO Software to interface with EXCEL and evaluate diversified scenarios. The results showed that the method of multiple mines is a technical and economically viable method for mine planning at the Itabira Complex.

Cette thèse porte sur l’étude du comportementdes bandes de convoyeurs soumisesà des contraintes mécanique, thermique et hydrique.La bande est constituée par un renforttextile multi-plis incorporé dans deux couchesde revêtement en caoutchouc. Le matériau dela bande en composite structural a été caractériséexpérimentalement à l'aide des essais mécaniqueset hydriques sur des éprouvettes normaliséesen composites avec et sans couche decaoutchouc. Des essais d’impact sont élaborésà fin d’identifier les différents modesd’endommagement à l’aide des observationsmicroscopiques.Une étude expérimentale est élaborée sur laméthode de réparation de la bande par collagede patchs internes en utilisant deux procédés decollage : la polymérisation à froid et la vulcanisationà chaud. Deux modèles analytiques unidimensionnelet bidirectionnel sont développéset confrontés aux modèles par éléments finispour étudier le comportement hygrothermomécaniquede la bande à l’aide des donnéesde caractérisation expérimentale. Les résultatsont montré que les performances de laméthode de réparation dépendent de différentsparamètres hygro-thermomécaniques et géométriques.Un outil d’aide à l’amélioration et à laconception en tenant compte de ces paramètresest enfin proposé. / This thesis deals with the study of themechanical behavior of a conveyor belt underhydrothermal effects. The structure that hasbeen studied consists of a 4 textile layers boundtogether by a thin rubber adhesive layer andcovered with the rubber cover. The beltcomposite structural was characterized usingstandard specimens with and without rubberlayers under tensile and ageing tests. Impacttests are developed to identify the differentdamage modes using microscopic observations..Experimental study of reparation method waselaborated using two processes: hotvulcanization and cold polymerization. Twoone-dimensional and bidirectional analyticmodels are developed and compared with finiteelement models to study the hygrothermomechanicalbehavior of the belt usingexperimental characterization parameters. Theresults showed that the performance ofreparation method of the belt depends ondifferent parameters. A tool for improvementand designing of the reparation is proposedtaking into account these parameters

Orientador: Luiz Sérgio Amarante Simões / Banca: Hardy Jost / Banca: Marcelo Juliano de Carvalho / Resumo: Na porção norte do Maciço de Goiás são reconhecidas três faixas greenstone belt de idades arqueano/paleoproterozóicas denominadas de Crixás, Guarinos e Pilar de Goiás. A área em estudo está inserida na porção sul do Greenstone belt de Guarinos, sendo limitada a oeste e leste, através de contatos tectônicos, pelos gnaisses dos Complexos Caiamar e Moquém, respectivamente. O mapeamento geológico possibilitou uma individualização das unidades litológicas com nova interpretação do empilhamento estratigráfico bem como a caracterização de feições estruturais da área. O empilhamento das unidades foi dividido da base para topo nas formações Serra do Cotovelo (metaultramáfica); Serra Azul (metamáfica); Unidade A (associação de rochas metaultramáficas, metamáficas e psamo-pelíticas); Cabaçal (xistos carbonosos com formações ferríferas e gonditos) subdividida em Ca-1, Ca-2, Ca-3 e Ca-4; Aimbé, com uma subunidade inferior (formações ferríferas bandadas ricas em muscovita) e outra superior (metapelitos associados esporadicamente a formações ferríferas fácies óxidos); e São Patricinho (metapelitos, subordinadamente gonditos). Embora diversos trabalhos da literatura descrevam este empilhamento do greenstone de Guarinos como invertido, neste trabalho considera-se a sequência apresentada como normal devido, à ausência de estruturas geopetálicas, que pudessem mostrar a polaridade estratigráfica do pacote, e de estruturas tectônicas que indicassem situação de flanco invertido. Um pacote de metassedimentos psamopelíticos atribuídos na literatura ao "Grupo Araxá" está sobreposto à sequência vulcanossedimentar através de uma descontinuidade, interpretada neste trabalho como uma discordância estratigráfica e não como falha de empurrão de baixo ângulo, como descrito na literatura... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: In the North portion of the Maciço de Goiás three greenstone belt of Archaean/Paleoproterozoic age are recognized, namely: Crixás, Guarinos and Pilar de Goiás. The study area is located on the southern portion of the Guarinos Greenstone Belt, and is delimited by faults to the west an east with the gneiss of the Caiamar Complex and Moquém Complex, respectively. The geological mapping allowed the individualization of lithological units, new interpretation of the stratigraphic stacking and the description of structural features found in the area. Previous studies describe the stratigraphic stacking of the Guarinos Greenstone Belt as inverteded. However, in this work, the stacking is interpreted as normal, due to the lacking of geopetalic and tectonic structures that could indicate top and basis of the sequence. The stratigraphic stacking was divided, from basis to top in Serra do Cotovelo Formation (metaultramafic); Serra Azul Formation (metamafic); Unit A (metaultramafic, metamafic and psammo pelitic association); Cabaçal Formation (carbonous schists with iron formations and gondites), which was subdivided in Ca-1, Ca-2, Ca-3 and Ca-4; Aimbé Formations, which contains a basal (banded iron formations, rich in muscovite) and a top subunit (metapelites, associated with rare iron formations, oxide facies); and São Patricinho Formation (metapelites, with subordinated gondites). Although several studies in the literature describe this stacking of the greenstone Guarinos as inverted, this paper considers the sequence presented as normal due to the lack of geopetálicas, which could show the polarity of the stratigraphic package, and tectonic structures to indicate status limb inverted. A package of metasediments in the literature psammo pelitic assigned to the Group Araxá volcanic sedimentary is superimposed on the sequence... (Complete abstract click electronic access below) / Mestre

Lung cancer is the leading cause of cancer death in the United States, but a large fraction of cases is preventable. We use a spatial smoothing algorithm to identify a geographic pattern of high lung cancer mortality, primarily in the Southeast, which we call a lung cancer belt. Disease belts are an effective mode for conveying patterns of high incidence or mortality; formally defining this lung cancer belt may encourage increased public dialogue and more focused research. Public health officials could complement existing population lung cancer data with this information to help inform resource allocation decisions.

Les ceintures de radiation provoquent des dégâts irréversibles sur les satellites les traversant, détériorant ainsi les instruments de mesure embarqués. Les étudier est utile au développement de matériaux adaptés et résistants. Depuis les années 90, l'ONERA-DESP étudie les ceintures de radiations des planètes magnétisées, telle que la Terre ou Jupiter, grâce au modèle Salammbô. Salammbô prend en compte les processus physiques de l'environnement radiatif pour recréer les populations d'électrons peuplant les ceintures. Dans cette étude, il s'agit de développer un modèle des ceintures de radiations internes de Saturne, basé sur les travaux précédents. Avant les années 2000, Pioneer 11 et Voyager 2 ne permettaient pas un développement suffisamment avancé d'un modèle de ceintures de radiations de Saturne. La mission Cassini apporte ensuite quantités d'observations et de données pour mener une étude plus approfondie de ces ceintures. Cette thèse débute par l'analyse de la magnétosphère interne de Saturne : anneaux, satellites, nuages de neutres...L'interaction des particules des ceintures de radiations avec ces différents paramètres se traduit par le calcul de coefficients de diffusion. Ces coefficients sont intégrés à l'équation de transport et permettent de comprendre les mécanismes perturbant la distribution des électrons au sein des ceintures de radiations. Les résultats obtenus sont comparés aux mesures faites par les sondes Pioneer 11, Voyager 2 et Cassini. / Radiation belts cause irreversible damages to on-board instrument materials. Studies about radiation belts can be useful for development of materials that will stand such environment. Since the 1990's, ONERA develops models of radiation belts of magnetized planets, such as the Earth or Jupiter. These previous work lead to a physical model, named Salammbô. Salammbô is based on physical processes that dominate the planetary magnetosphere in order to recreate electron populations of radiation belts. ONERA is now able to develop an electron radiation belt model for Saturn's environment, i.e., a new version of Salammbô. Before the 2000's, Pioneer 11 and Voyager 2 did not allow a good development of a Salammbô model in the case of Saturn. Nowadays, the Cassini mission gives a lot of information about Saturn, its magnetosphere and its environment to start a study about radiation belts of Saturn. This thesis begins with the analyse of the kronian magnetosphere : rings, satellites, neutral clouds, etc. Interaction between radiation belt particle and these different parameters lead to diffusion coefficients. Diffusion coefficients are integrated into the Salammbô code and imply a better comprehension of mechanisms that can interfere with the electron distribution of radiation belts. Results have been compared with observations of Pioneer 11, Voyager 2 and Cassini spacecrafts.

Correias transportadoras têm sido utilizadas como um modo eficiente de transporte de materiais por diversos ramos da indústria. A vida útil desse equipamento é influenciada pelo desgaste natural ocasionado pelo uso excessivo e falhas, tais como rasgos, cortes e perfurações. Nesse trabalho, é proposto um método de identificação de falhas em correia transportadora por meio de processamento digital de imagens, combinadas com técnicas de escaneamento 3D a laser e aprendizado de máquinas (redes neurais e SVM (Support Vector Machine - Máquina de Vetores de Suporte)). A averiguação experimental foi efetuada em duas etapas: a primeira etapa inicia-se com a aquisição, o pré-processamento e a geração do banco de imagens; a segunda, com a extração e a classificação das amostras. O vetor de características foi submetido a dois classificadores: rede neural do tipo Perceptron Múltiplas Camadas (com 15 topologias candidatas) e um classificador SVM, variando sua função kernel: linear, quadrática, polinomial, gaussiano, RBF (Radial-Basis Function - Função de Base Radial) e MLP (Multilayer Perceptron – Perceptron Múltiplas Camadas). Os resultados experimentais mostram que a metodologia proposta obtém uma boa acurácia na estimação das falhas, mostrando-se promissora na tarefa de diagnosticar e classificar falhas em correias transportadoras. / Conveyor belts have been used as an efficient way of transporting materials by various industry branches. This equipment\'s lifespan is influenced by natural wear caused by overuse and flaws, such as tears, cuts, and perforations. This work proposes a method of identifying flaws in the conveyor belt using digital image processing, combined with 3D laser scanning techniques and machine learning (neural networks and SVM - Support Vector Machine). The experimental investigation has been carried out in two stages: the first stage begins with the acquisition, preprocessing, and generation of an image bank; the second, with the extraction and classification of the samples. The characteristic\'s vector has been submitted to two classifiers: Multi-Layer Perceptron neural network (with 15 candidate topologies) and an SVM classifier, varying its kernel function: linear, quadratic, polynomial, Gaussian, RBF (Radial-Basis Function) and MLP (Multilayer Perceptron). The experimental results show that the proposed methodology obtains a good accuracy in the failure estimation, being promising in the task of diagnosing and classifying flaws in conveyor belts.

Syftet med arbetet var att undersöka möjligheten för optimering av produktflödet. Företagets produkter transporteras på ett transportband till en gemensam process. Det nuvarande flödet till processen är inte optimerat vilket resulterar i att processen körs ineffektivt. Ackumulering av produkter innan processen ska därför undersökas som en lösning till problemet. Fyra olika ackumuleringsförslag har analyserats och jämförts: hängande bansystem, palleteringssystem, depalleteringssystem och kombination av bansystem och palleteringssystem. Förslagen har blivit bedömda och jämförda utifrån följande parametrar: yta, investeringskostnad, flexibilitet, arbetsbelastning, arbetsmiljö och tid. Hängande bansystem fick det högsta snittvärdet och valdes därför för fortsatt analys med stöd av simulering. Simuleringen gjordes i ExtendSim 7. Två simuleringsmodeller jämfördes, en med ackumulering av produkter i bansystem och en utan. Resultatet var att ackumulering av produkter kan ge en besparing på 16 procent i driftkostnader per år. Simulering av övriga förslag kan göras för att få en tydligare jämförelse mellan förslagen. Rekommendationen till företaget är att ackumulera produkter i ett bansystem. Det baseras på analys av jämförelsen. Analysen och diskussionen visar också att robothantering inte är en passande lösning på problemet, eftersom rörelserna skulle skaka om produkterna för mycket. En vidare undersökning av utformningen av bansystemet bör göras för att få fram den optimala utformningen. / The purpose of the work was to investigate possibilities for optimization of the material flow. The different products of the company are being transported by a conveyor belt to a common process. The current flow to the process is not optimized with the result that the process runs inefficiently. Accumulation of products before the process should therefore be investigated as a solution. Four different accumulating systems have been analyzed and compared: hanging conveyor belts, palletizing, depalletizing and a combination of conveyor belts and palletizing. The systems have been assessed and compared according to six parameters: area, investment cost, flexibility, work load, work environment and time. The hanging conveyor belt yielded the highest average score and was therefore chosen for further analysis with the support of simulation. The simulation was made in ExtendSim 7. Two simulation models were compared, one with accumulation of product in conveyor belts and one without. The result of the simulation part was that accumulation of product results in savings of running costs with 16 percent per year. To get a better comparison between the accumulation systems simulations of all systems can be done. The recommendation to the company is to accumulate products in a conveyor system. This is based on the analysis of the comparison. The analysis and discussion also shows that robot handling is not an appropriate solution to the problem, because the movements would shake the products too much. A further investigation of the layout should be done in order to find the optimal layout.

Scania är en av världens största tillverkare av lastbilar, bussar och marina motorer och examensarbetet har utförts i syfte att utveckla en ny remmätrigg för att bättre kunna verifiera slitage, livslängd och töjning efter olika testcykler på Poly-V remmar. Riggen skall utföra mätningar enligt standard SAE-J1459 och klara att mäta remlängder mellan 1000-3300 mm. Därtill måste konstruktionen vara utformad enligt gällande säkerhetsföreskrifter och ergonomiska aspekter beaktas. Mätningar av Poly-V remmar sker efter principen att remmen spänns in mellan två remskivor med en kraft på 100 N per ribba. Vid examensarbetets start fanns en äldre mätrigg att tillgå, vilken inte längre är i bruk p.g.a. att den inte uppfyller alla krav för mätprocessen. Den har dock använts i syfte för att identifiera ergonomi- och säkerhetsrisker. Påvisade risker har sedan beaktats vid utformningen av koncept, för att begränsa dessa vid konstruktion av den nya mätriggen. Konstruktionen av den nya remmätriggen är framtagen med hjälp av erkänd produktutvecklingsmetodik, med arbete från idé till färdig produkt. Allt i enlighet med en förstudie i konstruktionsmetodik, en konceptstudie som behandlar ett flertal koncept, konceptval och analys av teknisk utrustning som används i den nya konstruktionen samt konstruktionsarbete och utvärdering. Vid examensarbetets slut har en färdigmonterad remmätrigg levererats klar för användning. Konstruktionen klarar att mäta remlängder mellan 1000-3300 mm och upp till tolv ribbor. Mätprocessen enligt SAE-J1459 kan utföras samtidigt som riggen är utformat med ergonomi och säkerhet i åtanke. Tillhörande remmätriggen finns en användarmanual som beskriver rutiner kring användning av utrustningen, risker och själva mätprocessen steg för steg. I rapporten bilagas en förstudie inom ergonomi och säkerhet, som har utförts vid examensarbetets första fas med syfte att användas som grund vid utformningen av den nya riggen. Det för garantera att hänsyn är tagen till gällande ergonomi- & arbetsmiljö-föreskrifter. / Scania is one of the World greatest producers of trucks, busses and marine engines. The purpose of the master thesis has been to develop a new measuring rig for Poly-V belts, to better be able to verify wear, duration and elongation at different testing cycles. The rig shall do measurements following the SAE-J1459 standard and be able to perform on belts with length between 1000-3300 mm. In addition, the design must be made in accordance with safety regulations and ergonomic aspects. Measurement of Poly-V belts are carried out by straining the belt between to pulleys with a force of 100 N per crossbar. At the project start access was granted to an old measuring rig, which is no longer in use due to not fulfilling the requirements for the measuring procedure. However, it has been used to identify ergonomic and safety gaps. The development of new concepts has then been carried out with those gaps in mind. The design of the new measuring rig is developed by using proven product development methodology, which covers work from idée to completed product. That includes accordance with a pre-study in design methodology, a concept study which deals with a number of concepts, the selection of concepts and an analysis of the technical equipment used in the new design during the product design. The result of the thesis is a completed rig, delivered and ready to use. The rig is capable of measuring ribbed belt length between 1000-3300 mm and up to twelve ribs. Measurement process according to SAE-J1459 can be performed meanwhile the rig is designed with ergonomics and safety aspects. A user manual describing the use of equipment, risks and the actual measurement process step by step is also included with the rig. The report annexes a pre-study of ergonomic and safety, which has been written in the initial phase of the thesis. The pre-study has been used as a guide for the design of the new rig, taking into consideration the existing regulations from different acquis.

published_or_final_version / Earth Sciences / Doctoral / Doctor of Philosophy