The Guano-Guayes property, in the Pelly Mountains of the Yukon Territory, covers a rare earth element (REE) bearing contact metamorphic aureole which developed around a syenite stock during Mississippian time (319 ± 10 Ma phlogopite K-Ar date, 333 ± 10 Ma Rb-Sr skarn mineral isochron). Sedimentary rocks consist of several hundred metres of Ordovician dark gray shale which are faulted upward adjacent to 450 m of Silurian interbedded impure calcite and dolomite marbles and quartzites overlain by at least 500 m of Silurain quartzite. Sedimentary rocks are on the steeply, west-dipping limb of a regional anticline (the axis bears 162 degrees and plunges 24 degrees south). The syenite, at the southeast end of a northwest-trending belt of syenite stocks and associated volcanic rocks, consists of 40 to 90 percent orthoclase in laths up to several cm long, and of up to 60 percent mafic minerals now mostly altered to biotite. Rare earth element values of syenite, when normalized to chondritic values, have a crustal pattern with magnitude slightly higher than that of crustal rocks. Dikes, believed to be cogenetic with syenite, intrude sedimentary rocks within and inear the contact metamorphic aureole. These dikes are dark-coloured and originally contained up to 25 percent zircon (now partly altered to secondary minerals). Zircon is enriched in total REE and relatively enriched in light REE compared to syenite, probably due to selective partitioning of REE. REE patterns in skarn and sedimentary rocks suggest that fluids circulated through syenite and carried trace amounts of REE from it into the skarn. There was no significant movement of REE from dikes into skarn or sedimentary rocks. Contact metamorphic rocks can be divided into three units: quartz-muscovite hornfels, dark green diopsade-calcite-phlogopite-tremdlite-sphene skarn, and light green diopside-calcite-phlogopite skarn. Depth at time of intrusion of syenite, as estimated from regional geologic contraints, was around 1 to 2 km (circa 500 bars). Parageneses and textures observed in thin section in contact metamorphic rocks indicate that prograde metamorphism at this pressure reached a maximum temperature of 450 to 540 degrees C, with heat being transferred from the intrusive dominantly by fluids. The mole fraction of CO₂ in metamorphic fluids, increased By the liberation of CO₂ during prograde metamorphic reactions, was moderate. Large amounts of Fe, Mg, and possibly Si0₂, were added to the skarn. Retrograde metamorphism involved significant addition of water to the system, proven by the appearance of secondary epidote, chlorite, and, later, serpentine. Extensive retrograde metamorphism accompanied by large-scale migration of elements through syenite ended 206 ±15 Ma ago (syenite whole-rock isochron) and the last resetting event took place between 156 ± 5 Ma (K-Ar date on biotite-altered arfvedsonite) and 128 ± 25 Ma (syenite mineral isochron). Petrology, geochronometry, and rare earth element studies presented here have contributed to an understanding of the genesis of syenite, skarn, and mineralized dikes within the Guano-Guayes area. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Unknown

O trabalho tem como objetivo abordar e investigar a viabilidade técnica e econômica da proposta de substituição de um motor de corrente continua, por um motor síncrono com imãs permanentes. O passo inicial foi a análise de dados referentes à manutenção preventiva do motor em operação comparado ao motor de indução e o resultado foi que se teria grande vantagens. Foi observado que o mercado oferecia uma solução inovadora, que mudou a trajetória dos estudos. Esta solução é o motor síncrono de imã permanentes, que é um motor brushless de corrente alternada, com dimensões reduzidas para a mesma potência de um motor indução trifásico. As perdas por efeito Joule no rotor que praticamente são as maiores, neste caso são desprezíveis, pois o rotor é equipado internamente com imãs de Terras Raras, o Neodímio Ferro Boro de alta energia, que desta forma minimizam também a temperatura no motor aumentando sua vida útil. Além disso, para aplicações onde se tem a necessidade de controle de torque com velocidades baixas é a melhor solução. Estas e outras qualidades fizeram a diferença na escolha deste motor para a aplicação, onde é necessário o controle de torque com a velocidade baixa. Neste trabalho se descreve todas as etapas do retrofiting, incluindo as comparações do sistema atual com duas propostas, através de simulações no software MATLAB, que demonstraram que as expectativas iniciais foram alcançadas, identificando o motor síncrono de imãs permanentes mais indicado nos dias de hoje para a substituição. / The work had as objective approach and investigate the technical and economic viability of the proposed replacement of a DC motor, by a permanent magnets synchronous motor. The initial step was the analysis of data on preventive maintenance of the motor in operation compared to the induction motor and the result was that it would have great advantages. It was observed that the market offered an innovative solution, which changed the course of the studies. This solution is permanent magnet synchronous motor, which is a brushless AC motor with reduced dimensions at the same power of a three phase induction motor. The Joule losses in the rotor which practically are the biggest. this case are not important, because the rotor is fitted internally with Rare Earths Magnets Neodymium Iron Boron the high energy, which thus also minimize the temperature in the motor increasing its lifetime. Also, for application where there is the need to control torque at low speeds is the best solution. These and other qualities made the difference in the choice of this motor to the application, where it is necessary to control torque with low speed. We describe all stages of Retrofitting, including comparisons of the current system with two proposals, through simulations in MATLAB, which have shown that initial expectations were met, identifying the permanent magnet synchronous motor best suited these days for the replacement.

La possibilité d’obtenir une émission laser efficace sur une large bande spectrale autour de 1.05 µm a été démontrée récemment en utilisant des monocristaux CaF2 and SrF2 dopés Nd3+. Cette émission, éteinte du fait de la relaxation croisée entre ions dans les matériaux de type fluorite, peut être exaltée avec l’insertion d’ions “tampons” comme Y3+ ou Lu3+. Une émission laser accordable sur une large bande spectrale et la génération d’impulsions ultracourtes sont donc possibles. De plus, ce type de matériau est particulièrement intéressant pour des amplificateurs de forte puissance pompés par diodes. Une étude complète des propriétés spectrales et thermomécaniques de cristaux de CaF2:Nd3+ co-dopés avec des concentrations variables de Lu3+ a été menée en collaboration avec le CEA CESTA au sein du projet LASCAN pour de futurs développements au sein du Laser MégaJoule (LMJ) avec pour but l’amélioration des performances des amplificateurs pilotes. L’effet d’élimination des clusters de Nd3+ par le co-dopage avec le Lu3+ et l’apparition de deux sites actifs différents a été mise en évidence et caractérisée en détail. Ce travail présente ainsi une spectroscopie complète des centres actifs dans CaF2:Nd3+,Lu3+, une étude des propriétés thermomécaniques, ainsi que des propriétés d’amplification optique des matériaux étudiés. / It was recently demonstrated that efficient and broadband laser emission was possible with Nd-doped CaF2 and SrF2 single crystals around 1.05 µm. Such laser emission, known as completely quenched because of cross-relaxation in the singly doped fluorites, increases spectacularly by co-doping with non-optically active “buffer” ions like Y3+ or Lu3+. Broadband laser emission and ultra-short laser operation are therefore possible. The material is particularly appealing for large scale high peak power diode-pumped amplifiers. A deep investigation of the spectral properties of CaF2:Nd3+ crystals co-doped with various amounts of Lu3+ was performed. The cluster breaking effect of Lu3+ codoping has as a side-effect the appearance of two different contributions, identified as two different active sites, which is in agreement with recent observations. In this work, we investigate in depth the different centres’ spectroscopic properties and operational parameters for laser applications,their evolution as the lutetium concentration increases, and the thermomechanical properties of said samples. A preliminary investigation on the amplification properties and laser operation of said materials is performed as well.

The Paris Agreement aims to limit the global temperature to below 2°C above the pre-industrial level. In order to achieve this target, almost 200 countries committed to Nationally Determined Contributions to reduce their greenhouse gas emissions. Diverse strategies are applied to achieve the necessary emissions reductions. One such strategy is large-scale renewable energy deployment. Certain key minerals are needed to produce green technologies such as electric vehicles and wind turbines. This thesis is concerned with the minerals cobalt, lithium and rare earths which are key components of lithium-ion batteries and/or permanent magnets used in many green technology applications. The academic community is aware that these critical materials are largely found in fragile and undemocratic states. The question is how the energy transition may be impacted by the fragile state of critical mineral producing countries. Therefore, this thesis aimed to investigate the supply and geopolitical risks on the critical materials market in the short- and medium-term. An analysis of the markets and a projection of their future development were conducted through maximum depletion rate modelling, the calculation Herfindahl-Hirschman indexes and risk-weighting country index scores. The results showed that the mineral markets are projected to remain highly concentrated which points to a continued vulnerability to risks emanating from individual production countries. The study found that the kinds of risk categories impacting a market depend on the distribution of market shares among countries. As production constraints arise in individual countries, the risk portfolio of the market changes. The study also concluded that countries like China that invest in mining projects abroad can contribute to the risks of a mineral that they are not producing themselves.

[pt] Neste trabalho são reportados o preparo, a caracterização e os estudos de luminescência de filmes do polímero 1,7-polioxepan-2-ona (policaprolactona, PCL) dopados com complexos trisacetilacetonatos (acac) de Terras Raras trivalentes (TR igual a Eu3 positivo, Gd3 positivo e Tb3 positivo). Os dados de microanálise de CHN evidenciaram que a fórmula geral para os compostos precursores é (TR(acac)3(H2O)3). Os espectros de absorção na região do infravermelho (FTIR) e os espectros Raman indicaram que a coordenação dos ligantes B-dicetonas aos íons TR3 positivo ocorre através dos átomos de oxigênio dos grupos carbonila. Os filmes de PCL foram dopados com (TR(acac)3(H2O)3) em concentrações de 1, 5, 10, 15 e 20 porcento (m/m). Os dados de FTIR e Raman evidenciaram a interação entre o polímero PCL e os B-dicetonatos de TR. As análises termogravimétricas indicaram o caráter anidro das matrizes poliméricas dopadas e melhoria da estabilidade térmica comparados aos complexos precursores. Os espectros de emissão dos sistemas PCL:Eu e PCL:Tb apresentam bandas finas características das transições intraconfiguracionais dos íons Eu3 positivo (5D0-7F0-4) e Tb3 positivo (5D4-7F6-0) que exibem as cores vermelha e verde, respectivamente. Além de supressão de luminescência por concentração, também foram observadas perdas de intensidade da emissão dos filmes ao longo do tempo. Os filmes dopados com Eu3 positivo apresentam maiores tempos de vida do nível emissor 5D0 e eficiências quânticas, indicando que o PCL participa no processo de transferência de energia ligante-metal e co-sensibiliza os íons TR3 positivo. / [en] In this work we report the preparation, characterization and the luminescence studies 1,7-polyoxepan-2-one (polycaprolactone, PCL) polymer films doped with trivalent Rare Earth (RE = Eu3 positive, Gd3 positive e Tb3 positive) trisacetylacetonate (acac) complexes. The CHN microanalysis data confirmed that the general formula for the precursor compounds is (RE(acac)3(H2O)3). The absorption spectra in the infrared region (FTIR) and Raman spectra indicated that the coordination of the B-diketone ligands to RE3 positive ions occurs through the oxygen atoms of carbonyl groups. The PCL films were doped with (RE(acac)3(H2O)3) at concentrations of 1, 5, 10, 15 and 20 porcento (w/w). FTIR and Raman data demonstrated the interaction between PCL polymer and rare earth B-diketonates. The thermogravimetric analysis indicated the anhydrous character of the doped polymer matrices and improvement of thermal stability, in comparison with the precursor complexes. The emission spectra of the PCL:Eu and PCL:Tb systems present characteristic narrow bands of the intraconfigurational transitions of Eu3 positive (5D0-7F0-4) and Tb3 positive (5D4-7F6-0), exhibiting red and green colors, respectively. In addition to concentration quenching of luminescence, losses of emission intensities were also observed over time. The Eu3 positive-doped films exhibit higher lifetimes of the 5D0 emitting level and quantum efficiencies, indicating that the PCL participates in the ligand–metal energy transfer process and co-sensitizes the RE3 positive ions.

DNA serves as a mode of storage for genetic information and carries essential biophysical functions which continue to gain importance for new biomolecular applications. The functionalization of proteins with nucleic acids has found several different uses in a variety of fields such as DNA origami due to the highly programmable nature of DNA. The modulation of key biomolecular properties of proteins by the conjugation of DNA nanotools, mechanical forces and potential catalytic modulators is an under discovered area of protein engineering. In this doctoral thesis work, functionalization strategies of proteins with DNA oligonucleotides, the catalytic mechanism of AdhD from Pyrococcus furiosus and effects of mechanical forces on enzymatic catalysis have been investigated through the utilization of DNA tools. In the first part of the thesis (Chapter 2), several bioconjugation strategies which can be used to attach DNA oligonucleotides to proteins have been reviewed and assessed for emerging biomolecular applications. This work provides insights about commonly used bioconjugation reactions and investigates the performance of each conjugation reaction in terms of yield, site- specificity, flexibility in conjugation position, steric hinderance, cost, reagent availability and risk of altering native protein properties. In the next section of the thesis (Chapter 3), DNA spring attachment sites are strategically modeled and created on the model enzyme for assigned bioconjugation strategies and the DNA springs are assembled on this model enzyme. The effect of the forces generated by the DNA springs during bulk catalysis is investigated and the changes in binding pockets and substrate specificity properties are demonstrated. A novel magnetic bead-based purification strategy for the separation of DNA spring conjugated enzyme is established in this work to ensure homogenous catalysis conditions. This construct allows the tuning of catalytic properties by the usage of different lengths of DNA and is shown to be reversible. As enzymatic catalysis is investigated under bulk conditions and the amino acid sequence within the active site is not altered, this strategy provides a new platform for the modulation of enzymatic trajectories without isolation and altered microenvironment limitations as well as the irreversible effects of conventional techniques such as mutagenesis and directed evolution. In the last part of the thesis (Chapter 4), the effects of different DNA constructs on AdhD are investigated. Convex DNA springs are constructed on AdhD molecules with the goal of applying compressive forces over the active site. In addition, DNA tweezers are designed to apply comparable forces to the DNA spring studied in Chapter 3, assembled on AdhD and purified using the same magnetic bead-based strategy. This construct, as discussed in Chapter 1, allows the modulation of substrate specificity profiles consistent with its mechanical design. As a continuation of the last part of the thesis, the rare earth element (REE) binding capacity of AdhD and the effect of metal binding on its enzymatic trajectory are investigated in Chapter 5. The rare earth element (REE) binding affinity of AdhD and its effect on enzymatic catalysis on both the forward and reverse reactions are demonstrated with and without the presence of a metal chelator. This discovery sheds light on the potential allosteric regulation mechanisms of AdhD and the catalytic regulator effect of REEs. The work presented in this doctoral thesis demonstrates different biomolecular approaches towards the modulation of enzymatic properties through DNA oligonucleotide conjugation, application of mechanical forces and potential catalytic regulators. In the future, the results presented in this work can be utilized to initiate in depth studies about protein-DNA conjugation and modulation of enzymatic catalysis, and discover extended applications which can be used universally across different biomolecular platforms.

No / Two new complexes, [Fe3(μ3-O)(inicH)6(H2O)3][Gd(NO3)6]·(NO3)4·nH2O (1) and [Fe3(μ3-O)(inicH)6(H2O)3][Dy(NO3)5 (H2O)]·(NO3)5·n(H2O) (2) with two isolated complex moieties, were generated when isonicotinic acid was treated with iron(III) nitrate and the corresponding lanthanide(III) nitrate in water. The structures were determined by single-crystal X-ray diffraction studies. In these compounds, the anionic lanthanide complexes are encapsulated by trinuclear [Fe3(μ3-O)(inicH)6(H2O)3]7+ cationic cluster units, which is facilitated by hydrogen-bonding interactions. Investigation of the magnetic properties reveals that 2 shows slow relaxation of magnetization at low magnetic field (Hdc = 1.0 kOe), with an energy barrier of 23 K originating from a single [Dy(NO3)5(H2O)]2– anion. / Errata: 2014(25): 4228 (http://onlinelibrary.wiley.com/enhanced/doi/10.1002/ejic.201402684)

No / This article corrects http://onlinelibrary.wiley.com/enhanced/doi/10.1002/ejic.201402114. 2014(19): 3065-3071.

Luminóforos inorgânicos contendo Terras Raras (TR) apresentam um papel importante como detectores de radiação ionizante, aplicados em diagnósticos médicos por imagem, como radiologia e tomografia. A função dos luminóforos é transformar os fótons da radiação de alta energia absorvidos (raios X ou ?) em fótons de luz visível, promovendo melhor qualidade de imagem e, conseqüentemente menor tempo de exposição do paciente à radiação. Os luminóforos de TR consistem de uma matriz hospedeira onde estão presentes íons de TR como Lu, La, Y ou Gd e de um íon ativador (que emite luz na região visível do espectro) como Eu3+, Tb3+, Tm3+ ou Ce3+, por exemplo. Luminóforos contendo íons Ce3+ como ativador são alvo de várias pesquisas relacionadas com detecção de radiação ionizante, devido às rápidas transições 5 d ? 4 f (tempo de resposta de ~ 10 a 100 ns) e emissão de luz na região do azul ou verde, requisitos esperados para um eficiente luminóforo para tal aplicação. Este trabalho apresenta a preparação de luminóforos de TR, dopados com Ce3+ ou Tm3+, na forma de pó, por diferentes métodos de síntese, como os métodos de combustão e Pechini e também por processo sol-gel. Aluminatos de TR (Lu3Al5O12 e Y3Al5O12) dopados com cério ou túlio foram obtidos pela reação de combustão entre precursores nitrato com uréia ou glicina sob aquecimento, ou pela síntese de polímeros de ácido cítrico com etilenoglicol contendo íons TR e alumínio (método Pechini). Em ambos os métodos os compostos foram obtidos por calcinação a temperaturas baixas quando comparadas às dos métodos convencionais. Silicatos de TR (Gd2SiO5, Lu2SiO5 e Y2SiO5) dopados com cério ou túlio foram preparados pelo método sol-gel convencional, por reação entre tetraetóxisilano (TEOS), etanol, água e nitratos metálicos, sob catálise básica, e por um método sol-gel modificado utilizando um polímero precursor. Neste último procedimento, TEOS, etanol e água reagiram juntamente com um sal orgânico de TR, álcool polivinílico (PVA) e uréia como combustível, produzindo um gel. Posterior calcinação levou à formação do silicato. A caracterização dos compostos foi realizada por análises de difratometria de raios X pelo método do pó (DRX), microscopia de eletrônica de varredura (MEV) ou de transmissão (MET), EDX, excitação e emissão no UV-Vis e tempo de vida de luminescência. Para os aluminatos dopados com cério foram ainda realizados espectros de emissão sob excitação por raios X. Os métodos de síntese utilizados se mostraram eficientes para obtenção de luminóforos na forma de pó nanométrico, com exceção do método sol-gel modificado, pois para algumas amostras observou-se a formação de mistura de fases. Os compostos dopados com cério apresentaram excitação e emissão características desse íon na região do verde ou azul do espectro visível, dependendo da matriz, com tempos de vida menores que 100 ns. Já aqueles dopados com túlio apresentaram emissão característica do íon, na região do azul, porém com tempos de vida da ordem de microssegundos. / Rare Earth (RE) inorganic phosphors play an important role as ionizing radiation detectors when applied to medical imaging techniques like radiology and tomography. These phosphors is to convert the high energy radiation absorbed photons (X or ?-rays) into visible photons, leading to better quality images and reducing the time the patient is exposed to radiation. RE phosphors consist of a host lattice where RE ions such as Lu, La, Y, or Gd are present, as well as activator ions (which emit light in the visible range of the spectrum) such as Eu3+, Tb3+, Tm3+, or Ce3+. Cerium-doped phosphors have been the target of several researches related with ionizing radiation detection due to their 5d - 4 f fast transitions (decay time in the ~ 10 to 100 ns range) and due to the fact that they emit light in the blue or green region of the spectrum, which is required for to the efficient phosphors to be applied in the detection of X or ?-rays. This work presents the synthesis of RE phosphor powders doped with Ce3+ or Tm3+, through different synthetic methods: combustion, Pechini, and sol-gel. RE aluminates (Lu3Al5O12 and Y3Al5O12) doped with Ce or Tm were prepared by combustion reaction between nitrate precursors and urea or glycine under heating. They were also obtained via the synthesis of polymers using citric acid, ethileneglycol, RE3+ and Al3+ ions (Pechini method). In both cases, the compounds were obtained by calcination at lower temperatures than those used inconventional methods. RE silicates (Gd2SiO5, Lu2SiO5 e Y2SiO5) doped with Ce or Tm were synthesized by the conventional sol-gel method using tetraethoxisylane (TEOS), ethanol and water, under basic catalysis, and also by a modified sol-gel route that uses a polymeric precursor. In the latter one, TEOS, ethanol and water were reacted with an organic RE salt, polyvinyl alcohol (PVA), and urea was used as fuel, thus yielding a gel. After calcination, we observed silicate formation. Characterization of the compounds was performed by X-ray diffractometry (XRD ? powder method), scanning or transmission electron microscopy (SEM or TEM), energy dispersive X-ray (EDX), luminescence spectroscopy in the UV-Vis range and lifetime analyses. For the cerium doped aluminates, emission spectra under X-ray excitation were also obtained. The synthetic methods used here showed to be efficient for the preparation of nanometric phosphor powders except for the modified sol-gel route, because in this case formation of a mixture of phases was observed for some samples. The Ce-doped compounds exhibited excitation and emission features of this ion in either the green or blue region of the visible spectrum, depending on the matrix, with lifetime values lower than 100 ns. However, the Tm-doped compounds displayed the blue emission typical of Tm ions, but the lifetime values were in the range of microseconds.

This study investigates the photoluminescence (PL), cathodoluminescence (CL), radioluminescence (RL) and ionoluminescence (IL) of natural and synthetic minerals. The natural minerals (fluorapatite, leucophanite, meliphanite and zircon) are mostly from Ilímaussaq Alkaline Complex in South Greenland, Langesundsfjord in Norway and from different localities within Scotland. Synthetic fluorapatite (manufactured as part of the present study) and zircon doped with rare earth elements (REE) were used to compare single and multidoped materials. This study has shown that many of the generally accepted applications of luminescence are not as straightforward as often suggested by the current literature. For example, the study demonstrates how site distribution of REE, based on luminescence, is greatly affected by the dopant level and structural changes, and that different conclusions can be drawn on the same sample depending on method applied. Furthermore, it is clearly demonstrated that using luminescence as a tool for quantitative trace element determination is not going to be a standard technique in the near future if ever. The two main findings supporting this conclusion are the non-linear intensity decrease between different REE activators in the same sample and a large variation between activators at the concentration at which self-quenching starts. In contrast to the general perception that luminescence related to REE is mostly independent of the host, this study has shown a strong interaction between host and REE activators. This conclusion is supported by the change in the activator’s coordination polyhedron observed with single-crystal and powder X-ray diffraction combined with full chemical characterisation. When combining the weak interaction between some REE with the strong host interaction this study has shown the potential for designing new types of colour tuneable and “white light” LEDs based on natural minerals. This study also reveals that zircon doped with Gd³⁺ and Eu³⁺ can potentially have quantum-cutting properties.