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A novel paste deposition process was developed to widen the range of possible materials and applications. This experimental process developed an increasingly complex series of additive manufacturing machines, resulting in new combinations of novel materials and deposition paths without sacrificing many of the design freedoms inherit in the craft process. The investigation made use of open-source software together with an approach to programming user originated infill geometries to form structural parts, differing from the somewhat automated processing by 'closed' commercial RP systems. A series of experimental trials were conducted to test a range of candidate materials and machines which might be suitable for the PDM process. The combination of process and materials were trailed and validated using a series of themed case studies including medical, food industry and jewellery. Some of the object created great interest and even, in the case of the jewellery items, won awards. Further evidence of the commercial validity was evidenced through a collaborative partnership resulting in the development of a commercial version of the experimental system called Newton3D. A number of exciting potential future directions having been opened up by this project including silicone fabrics, bio material deposition and inclusive software development for user originated infills and structures.

A thesis submitted to the Faculty of Engineering and the Built Environment, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Doctor of Philosophy. Johannesburg, 2016 / The Precious Metals Industry in South Africa is highly-regulated compared with other mining and trading countries in the western world which have either deregulated their precious metals industries, have only partial controls or have never seen the need to regulate gold and platinum-group metals specifically. South Africa has a specific Act of parliament, the Precious Metals Act, 2005 (a modification of Chapter 16 of the Mining Rights Act, 1967), that regulates possession, trading and manufacture of precious metals. Apart from the Russian Federation, no other country in the world regulates gold and platinum-group metals possession, trading and fabrication to the extent still done in South Africa. The requirement for such stringent controls was based on the country’s pre-eminence in the production of gold and platinum over the past fifty years, exchange controls (in the case of gold) and the contribution of gold and platinum-group metals to foreign exchange earnings and to the country’s economy as a whole. However, much has changed in South Africa, in the world and indeed in the precious metals industries domestically and globally and this work is the first attempt to discuss and analyse developments and proposals that are impacting on the regulation of the precious metals industries in South Africa. Of these, the World Gold Council’s Conflict-Free Gold Standard provides a case for industry self- regulation to complement, or substitute for government regulation in future. The hypothesis at the Proposal Stage of this study was that the precious metals industry in South Africa is over-regulated and should be deregulated. In this study, this hypothesis is explored and debated. The Resource Nationalism -motivated proposals, including Producer-Country Price for Platinum, OPEC-type trade bloc for platinum, precious metal exchange and single-channel marketing of platinum, were analysed in this study. It was concluded that these are wanting in terms of cost/benefit or problematic in terms of international agreements and trade and competition laws. iii The Precious Metals Act, 2005 itself was also critically analysed with a view to evaluating what could be regulated better or deregulated in the light of recent developments and proposals. It was found, ironically, that the old problem of illegal mining and trading needs to be brought under control before deregulation of the precious metals industry can begin. Nevertheless, in the run-up to deregulation (in an estimated 10 to 15 years), industry self-regulation, co-regulation (with industry) hallmarking, and a re-examination of how beneficiation is promoted should be considered.

The present study focuses on the characterization of solid-liquid extraction techniques for the separation and preconcentration of rare-earth elements and precious metals. We developed an impregnated resin with di (2-ethylhexyl)phosphoric acid (D2EHPA) in order to separate rare-earth elements / Els treballs realitzats es centren en la caracterització de sistemes d’extracció sòlid-líquid per a la separació i preconcentració de terres rares i metalls preciosos. Amb aquest objectiu es varen avaluar diferents resines quelants, majoritàriament disponibles comercialment, per a la separació i recuperació de metalls preciosos, així com la seva aplicació a processos en columna utilitzant llits de resina fixos. També s’inclou la caracterització del procés de separació d’itri i neodimi mitjançant una resina impregnada amb dissolvent

Noble metal nanostructures possess unique properties including large near-field enhancement and strong light scattering and absorption due to their plasmon resonance - the collective coherent oscillation of the metal free electrons in resonance with the electromagnetic field of light. The effect of nanostructure size, shape, composition, and environment on the plasmon resonance frequency and plasmonic enhancement is well known. In this thesis, we describe the effect of inter-particle coupling in assembled plasmonic nanostructures on their radiative and non-radiative properties. When metal nanoparticles assemble, plasmon oscillations of neighboring particles couple, resulting in a shift in the plasmon resonance frequency. Our investigation of plasmon coupling in gold nanorods shows that the coupling between the plasmons is "bonding" in nature when the plasmon oscillations are polarized along the inter-particle axis, whereas an "anti-bonding" interaction results when the polarization is perpendicular. We studied the distance-dependence of plasmon coupling using electrodynamic simulations and experimental plasmon resonances of lithographically fabricated gold nanoparticle pairs with systematically varying inter-particle separations. The strength of plasmon bonding, reflected by the fractional plasmon shift, decays near-exponentially with the inter-particle separation (in units of particle size) according to a universal trend independent of the nanoparticle size, shape, metal type, or medium. From the universal scaling model, we obtain a "plasmon ruler equation" which calculates (in good agreement with the experiments of Alivisatos and Liphardt) the inter-particle separation in a gold nanosphere pair from its plasmon resonance shift, making it applicable to the determination of inter-site distances in biological systems. Universal size-scaling is valid also in the metal nanoshell structure, a nanosphere trimer, and pairs of elongated nanoparticles, thus making it a generalized fundamental model, which is useful in optimizing plasmon coupling for achieving tunable plasmon resonances, enhanced plasmonic sensitivities, and large SERS cross-sections. Ultrafast laser pump-probe studies of non-radiative electronic relaxation in coupled metal nanospheres in aggregates and in gold nanospheres conjugated to thiol SAMs are also reported. We also show that the relative contribution of scattering (radiative) to absorption (non-radiative) part of the plasmon relaxation, respectively useful in optical and photothermal applications, can be increased by increasing the nanostructure size.

In the first section, the electrical conductivity of rhodium phenylene-diisocyanide polymer is reported to be 3.4E-11 S/cm. However, the conductivity also exhibits an inverse exponential decay in air with t = 8 days. This change is attributed to the oxidation of the isocyanide functional group to an isocyanate, leading to degradation in the long-range metal-metal bonding, the dominant conductivity mechanism. Using a more stable carboxylate ligand, the Cu terephthalate (TPA) system is studied and compared against the Mg, Co, Ni, and Zn terephthalates. A synthesis in N,N-dimethylformamide (DMF) is developed and large quantities of the Cu(TPA)DMF can be synthesized in air. The crystal structure of the Cu(TPA) DMF is shown to be in the C2/m spacegroup. Upon desolvation, the Cu(TPA) is shown to have a large surface area of 625 m2/g. The magnetic susceptibility of the Cu(TPA) indicates anti-ferromagnetic coupling between adjacent Cu centers in the same dimer. The thermal stability of the Zn, Ni, Co, and Mg terephthalates is shown to increase with decreasing symmetric carboxylate stretch in the IR. The magnetic susceptibilities of the Co and Ni terephthalates have paramagnetic behavior, with a Weiss temperature of T = -12.9 K and T = 8.8 for Co(TPA) DMF and Ni(TPA)DMF respectively. A heterometallic Zn-Cu terephthalate is synthesized with Cu concentrations ranging from 0 to 100%. Upon the addition of Cu, Zn-rich frameworks increase in surface area, change in thermal stability, and increase their solvent retention from 16% to 25%. Zn is shown to couple with Cu in the same dimer at a high rate, changing the behavior of the dimer from anti-ferromagnetic to paramagnetic. The Weiss temperature suggests weak ferromagnetic interaction.

À ce jour, la récupération de métaux précieux contenus dans les déchets d’équipements électriques et électroniques (DEEE) se fait par des procédés présentant un niveau de dangerosité certain du fait de l’utilisation de cyanure ou d’eau régale qui impactent l’environnement avec une toxicité notoire pour l’homme dans le cas des cyanures. C’est dans la perspective de répondre à ces enjeux environnementaux que le projet PEPITE a été construit en associant un industriel (RECUPYL®) le LEPMI avec le soutien de L’ADEME. L’objet du projet vise à récupérer les métaux précieux contenus dans les DEEE par un procédé utilisant des liquides ioniques (LIs). Les travaux ont permis de compiler une base de connaissance très utile sur les propriétés physicochimiques des liquides ioniques retenus. Nous avons également pu bâtir un schéma de traitement aussi efficace mais sans rejet de gaz toxiques ou d’effluents. Les résultats de nos travaux ont conduit à l’émergence d’une nouvelle voie de recyclage par chimie verte grâce à l’application des liquides ioniques. Enfin, cet avantage environnemental s’accompagne d’une viabilité économique en regard des procédés actuels. / To date, the recovery of precious metals contained in waste electrical and electronic equipment (WEEE) reported a significant level of danger due to the use of cyanide or aqua regia extremely harmful and dangerous to the humans and the environment. This is in view to respond to environmental and economic issues that RECUPYL® society, LEPMI laboratory and the French Environment and Energy Management Agency (ADEME) developed the PEPITE project. It aims to recover the precious metals contained in WEEE by a hydrometallurgical process using ionic liquid electrolytes (ILs). This work led us to establish a knowledge base and to make measurements on the physico-chemical properties of LIs. We were able to develop a process flow sheet without release neither toxic gases nor effluents. The research work undertaken has led to significant results and demonstrated that there is a real solution for the recovery of precious metals in ionic liquid electrolyte.

This dissertation assesses the significance of luxury dining ware within Roman society by analyzing the economic and socio-cultural value of these objects. Specifically, I focus on silver and gold tableware from the Roman Republic through the third century CE. Precious metal vessels are particularly well-suited to a study of socio-economical value because they are somewhere between an art object and a commodity. Because these objects are made from silver and gold, they have material value, but they are also valuable for their functionality within the dining context, particularly for hosting guests at the convivium. Their utility is, therefore, expressly social in nature. In the Roman world, silver and gold vessels were also highly decorative and as such served as display pieces and objects of attention. Their ability to communicate was not limited only to their material or their functionality; they were neither mere utilitarian commodities, nor simple stores of wealth. Scholars often note that precious metal vessels were status symbols and stores of wealth, but they rarely analyze the way that these objects functioned within those roles. I seek to address this issue by considering the different forms of attention and the processes of valuation which were applied to luxury products in the Roman period. I will ask how social and cultural contexts affected the value of precious metal tableware and how the monetary value of these items determined the social contexts in which they were used. Additionally, this dissertation includes a study of the epigraphic habits on surviving silver and gold tableware in order to better understand how these vessels were used and exchanged. The inscriptions give a sense of the kinds of attention that was given to these objects and the way in which owners or makers might use them to communicate. I will approach these questions through an analysis of four primary types of value: economic, cultural, social, and aesthetic value. Value can be an economic measure achieved by quantifying the significance of an object and expressing this as price. But value can also be applied through cognitive processes via the attention paid to objects and the attitudes of people towards them. By looking at the significance of tableware as a luxury product, utility object, and display piece, I take account of the different ways in which these vessels could be used to communicate within social contexts. I will show that the value of precious metal tableware, in both an economic and cultural sense, provided its owners with opportunities to convey particular messages aimed at navigating the fraught networks of status that existed in Roman society. Gold and silver dining ware could be a store of wealth, but not one which produced financial returns like other assets. Rather, the benefits of storing wealth as luxury dining products were social in nature. The use of precious metal dining ware at communal dinners, or for display, could project an image of wealth, taste, and, most of all, generosity. The return on assets of silver and gold dining ware was social rather than financial capital. Luxury commodities like silver and gold plate were enmeshed in the social interactions and behaviors of elite Romans and so become agents in defining the social personas of their owners.

This dissertation explores a crucial period in the monetary geography of the Atlantic economy by examining the market for gold and silver coins (specie) in New Orleans between the Panic of 1839 and the U.S. naval blockade of the Confederate port in 1861. Situated at the intersection of global financial history and U.S. economic and business history, the dissertation reconstructs New Orleans’ supply chain of precious metals, shedding light on the port’s strategic role linking mining regions to specie-scarce nations under international bimetallism, and reveals how commission merchants, cotton factors, and merchant banks’ agents relied on metallic liquidity to engage in international trade and financial intermediation during a crucial era for nation-building and economic development in the Americas. The dissertation employs three main research strategies: (1) statistical and geographic analyses of a novel specie imports dataset (the first of its kind in the scholarly literature on specie in the early U.S. economy), extracted from the New Orleans Price-Current, a semi-weekly business newspaper, (2) group profiles and social network analysis of specie importers, leveraging multi-archival research and case studies of individuals, families, and banking and financial entities, (3) historical statistics on U.S. specie imports and Mexican specie production and exports. Chapter 1 reveals New Orleans’ centrality in the antebellum U.S. specie market and its strategic position in securing and shipping specie for the Atlantic economy under international bimetallism. Chapter 2 examines the demand side of the New Orleans specie market by focusing on the port’s cosmopolitan community of specie importers. Foreign residents received more specie than U.S. importers and New Orleans banks combined. The Louisiana Creole commission merchant and cotton factor Edmond Jean Forstall was the market’s key arbitrageur. Importers sorted into “silver barons” and “gold princes:” foreign residents handled mostly Mexican silver, while English residents, Anglo-Americans, and New Orleans banks obtained primarily gold. Chapter 3 focuses on the production and exports of Mexican specie to New Orleans. The port’s commission merchants exported British, Western European, and U.S. goods to Mexico in exchange for pesos (dollars); they reshipped U.S. cotton and Mexican pesos to European markets demanding specie for currency arbitrage operations in Europe and trade with China. Although New Orleans rapidly obtained metallic liquidity amid episodes of financial distress such as the Panic of 1857, its specie supply chain was highly vulnerable to disruptions from geopolitical shocks such as the Mexican-American War (1846-1848) and the U.S. Civil War.

Submitted by Olivier Boileau (olivier.boileau@hotmail.fr) on 2016-02-18T13:44:30Z No. of bitstreams: 1 Final-Report-FGV-by-Olivier-Boileau.pdf: 1435700 bytes, checksum: 5726e91bb0509cf4b3f5afd9acd70f3b (MD5) / Approved for entry into archive by Ana Luiza Holme (ana.holme@fgv.br) on 2016-02-18T13:45:44Z (GMT) No. of bitstreams: 1 Final-Report-FGV-by-Olivier-Boileau.pdf: 1435700 bytes, checksum: 5726e91bb0509cf4b3f5afd9acd70f3b (MD5) / Made available in DSpace on 2016-02-18T13:53:32Z (GMT). No. of bitstreams: 1 Final-Report-FGV-by-Olivier-Boileau.pdf: 1435700 bytes, checksum: 5726e91bb0509cf4b3f5afd9acd70f3b (MD5) Previous issue date: 2016-02-19 / Using regression and correlation approaches covering the last twenty years of daily data for seven countries, this thesis investigates safe haven and hedge abilities of precious metals against international equities over a given state of the economy. Furthermore, this thesis examines different portfolios performance in-samples and out-of-samples with the aim to observe whether investing in precious metals can help to mitigate investor risk management. The key results are: (i) Gold is the finest precious metal for international hedging against equities (ii) Gold provides valuable portfolio risk management benefits (iii) 60/40 portfolios allocated with gold proffer good investor outcomes. / Recorrendo a duas abordagens diferentes, regressão e correlação, e cobrindo os últimos vinte anos de dados diários para sete países, esta tese investiga as propriedades "safe haven" e "hedge" dos metais preciosos, em comparação com acções internacionais para um dado estado da economia. Adicionalmente, esta tese avalia o desempenho de diferentes portfolios, dentro e fora da amostra, com o objectivo de verificar se o investimento em metais preciosos poderá ajudar a atenuar a gestao do risco por parte do investidor. Os principais resultados são os que se seguem: (i) O ouro é o melhor metal precioso para um "hedging" internacional em oposição às acções (ii) O ouro permite obter valiosos benefícios de gestão de risco do portfolio (iii) 60/40 dos portofios atribuidos com ouro permitem ao investidor obter bons resultados.