An infinitely variable transmission (IVT) is a transmission that can smoothly and continuously vary the speed ratio between an input and output from zero to some other positive or negative ratio; they are a subset of continuously variable transmissions (CVTs), which themselves do not have the ability to produce a zero gear ratio. In this thesis, the operation, analysis, and development of a novel, highly configurable, Cam-based Infinitely Variable Transmission of the ratcheting drive type is presented. There are several categories of CVTs in existence today, including traction, belt, and ratcheting types. Drives of these types, their attributes, and associated design challenges are discussed to frame the development of the Cam-based IVT. The operation of this transmission is kinematically similar to a planetary gearset, and therefore, its operation is described with that in mind including a description of the six major components of the transmission, those being the cam, followers, carriers, planet gears, sun gears, and one way clutches. The kinematic equation describing its motion is derived based on the similarities it shares with a planetary gearset. Additionally, the equations for the cam design are developed here as the operation of the CVT is highly dependent on the shape of the cam. There are six simple inversions of this device and each inversion has special characteristics and limitations, for example, the available gear range. A method was developed to select the most suitable inversion, gearing, and follower velocity for a given application. The contact stress between the rollers and cam is the limiting stress within the transmission. A parametric study is used to quantify the relationship between this stress and the transmission parameters. Based off those results, two optimization strategies and their results are discussed. The first is an iterative brute force type numerical search and the second is a genetic algorithm. The optimization results are shown to be similar and successfully reduced the contact stress by 40%. To further improve the transmission performance, several mechanisms were developed for this unique transmission. These include a compact and lightweight differential mechanism based on a cord and pulley system to reduce the contact force on the rollers. In addition, a unique external/inverted cam topology was developed to improve the contact geometry between the rollers and said cam. A prototype was built based on both the optimization strategies and these mechanisms and is described within. Finally, a Prony brake dynamometer with cradled motor was constructed to test the transmission; the results of those tests show the Cam-based IVT to be 93% efficient at low input torque levels. / Master of Science

Conselho Nacional de Desenvolvimento Científico e Tecnológico / Due to Diesel oil s mineral origin and marketing price, the consumption of this fuel by a tractor becomes one of the most important aspects at the time of its acquisition and use. Knowledge of the appropriate strategies in driving combined with correct selection of modern power transmissions can help farmers to reduce production costs. When driving the tractor of different ways with different types of power transmissions, more efficiently and cost-effectively, the fuel consumption changes. The following research aimed to evaluate the effects of different types of power transmission and driving strategies on fuel consumption of agricultural tractors. For this, two experiments were conducted at the Agricultural Mechanics Station, Madrid, Spain, using two tractors, one equipped with Powershift transmission and the other with Continuously Variable Transmission (CVT). Standard procedure has been applied considering six load levels (30; 40; 50; 60; 70 and 80%) by means of breaking with a dynamometer car instrumented in a concrete test track, at three travel speeds (5.16; 7.29 and 10.48 km.h-1). Furthermore, the tractor equipped with Powershift transmission was conducted in two ways: Full throttle; Gear up - throttle down. Already the tractor equipped with Continuously Variable Transmission was conducted using the automatic mode. The responses evaluated variables were speed and thermal efficiency of the engine and hourly and specific fuel consumption. Analysis of variance was performed and that presented difference the data were subjected to the Tukey s test (≤0.05) for comparison of averages. The results indicate that the Gear up - throttle down mode (Powershift transmission) can be recommended as a strategy of agricultural tractor driving, since savings may be obtained up to 29.39% of fuel in relation to the Full throttle, typically recommended by manufacturers. The specific fuel consumption of tractor equipped with Continuously Variable Transmission decreases as the load levels and travel speeds are incremented. / Por ser um combustível de origem mineral e devido ao preço de comercialização, o consumo de óleo Diesel de um trator torna-se um dos aspectos mais importantes a considerar no momento da sua aquisição e utilização. O conhecimento de estratégias adequadas na condução, aliado à escolha correta de modernas transmissões de potência podem auxiliar os agricultores a diminuírem os custos de produção. Quando se conduz o trator de distintas maneiras, com diferentes tipos de transmissão de potência, de forma mais eficiente e econômica, o consumo de combustível se altera. O objetivo deste trabalho de pesquisa foi avaliar o efeito de diferentes tipos de transmissão de potência e estratégias de condução no consumo de combustível de tratores agrícolas. Para isto, foram conduzidos dois experimentos na Estação de Mecânica Agrícola, Madrid, Espanha, utilizando dois tratores, sendo um equipado com transmissão Powershift e o outro com Transmissão Continuamente Variável. Para a avaliação utilizou-se procedimento normalizado, com aplicação de seis cargas parciais (30; 40; 50; 60; 70 e 80%), por meio da frenagem com um carro dinamométrico instrumentado, em pista de concreto, em três velocidades de deslocamento (5,16; 7,29 e 10,58 km.h-1). O trator equipado com transmissão Powershift foi conduzido de duas maneiras: Aceleração Máxima e Marcha Longa - Aceleração Reduzida. Já o trator equipado com Transmissão Continuamente Variável foi conduzido utilizando-se o modo automático. As variáveis respostas avaliadas foram a rotação e a eficiência térmica do motor, os consumos horário e específico de combustível. Foi realizada a análise de variância e os dados que apresentaram diferença foram submetidos ao teste de Tukey (≤0,05), para comparação de médias. Os resultados indicaram que o modo Marcha Longa - Aceleração Reduzida (transmissão Powershift) pode ser recomendado como uma estratégia de condução do trator agrícola, visto que podem ser obtidas economias de até 29,39% de combustível em relação ao modo Aceleração Máxima, normalmente recomendado pelos fabricantes. O consumo específico de combustível do trator equipado com transmissão Continuamente Variável diminui à medida que as cargas parciais e as velocidades de deslocamento são incrementadas.

The present work investigates the synthesis and nanocrystal deposition of some selected solid solutions of transition metal trihalides with 2-dimensional crystal structure - specifically, the solutions of CrCl3 – CrBr3, CrBr3 – CrI3, RhCl3 – RhBr3, RhBr3 – RhI3, CrCl3 – RuCl3, and CrCl3 – MoCl3. Theoretical simulations of phase equilibria and partial pressures were applied to estimate suitable synthesis conditions for phase-pure solid solutions, before the syntheses were subsequently performed practically. It was found that for most of the systems investigated, special conditions, such as an appropriate excess of halogen or a specific temperature range, are crucial for successful synthesis. The purity of the corresponding products was confirmed by X-ray powder diffraction. These measurements were further used to investigate the course of the lattice parameters within the series of mixtures in order to be able to observe potential deviations from ideal mixing behavior of the parent compounds. These investigations revealed only small or no deviation from Vegard’s law for all investigated systems except CrCl3 – MoCl3. For CrCl3 – CrBr3, CrBr3 – CrI3, RhCl3 – RhBr3, RhBr3 – RhI3 and CrCl3 – RuCl3, the prepared powder material with different compositions was further used for the deposition of high-quality nanocrystals on a substrate. For this purpose, chemical vapor transport was applied. Suitable deposition conditions were also previously estimated by simulations before finally performing an experimental optimization of the transport conditions. The 2D nanocrystals thus obtained generally exhibit heights in the low 2-digit nm range, while monolayers were also observed in the case of RhCl3 – RhBr3. The compositions of the deposited structures were analyzed by energy dispersive X-ray spectroscopy to detect possible enrichment effects of the solid solutions during vapor transport. With the knowledge of these relationships, nanocrystals with controllable composition can be deposited by the developed method. The high quality of the deposited nanocrystals was ensured by transmission electron microscopy, selected area electron diffraction, and X-ray photoemission spectroscopy. Depending on the system, selected material properties were determined using powder samples, bulk or nanocrystals, such as the photoluminescence behavior of the CrCl3 – CrBr3 and CrBr3 – CrI3 series or the optical band gap characteristics of the RhCl3 – RhBr3 and RhBr3 – RhI3 systems. Unlike for the previously mentioned systems, in the case of CrCl3 – MoCl3, strong deviations from an ideal linear course of the lattice parameters were observed, where several phase regions can be distinguished within the series. To explain these anomalies, structural models were developed that explain the anomalies with the formation of differently arranged Mo-Mo dimers within the crystal structure. These hypotheses were investigated by different characterization methods such as IR spectroscopy or SQUID measurements and confirmed the hypotheses within the limits of the validity of the applied methods. The simulative and experimental methods developed in this work can be applied to numerous similar systems of transition metal trihalides, but should also work for other classes of compounds. The nanocrystals thus made available are suitable for follow-up studies with respect to property changes upon downscaling.:1. Introduction 1 2. Theoretical Background 3 2.1. Properties of Selected Transition Metal Trihalides and Their Solid Solutions . . . 3 2.1.1. Crystal Structures of 2D Transition Metal Trihalides . . . . . . . . . . . . . 4 2.1.2. CrX3 (X = Cl, Br, I) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 2.1.3. RhX3 (X = Cl, Br, I) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 2.1.4. RuCl3 and CrCl3-RuCl3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 2.1.5. MoCl3 and CrCl3-MoCl3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 2.2. Solid Solution Formation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 2.2.1. Structural Aspects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 2.2.2. Chemical Aspects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 2.2.3. Thermodynamic Aspects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 2.3. Chemical Vapor Transport . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 2.3.1. Bulk and Nanocrystal Growth by CVT . . . . . . . . . . . . . . . . . . . . . . 11 2.3.2. CVT of Solid Solutions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 2.3.3. Simulation of CVT Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . 13 2.4. Vapor Phase Chemistry of Selected Transition Metal Trihalides . . . . . . . . . . . 15 2.4.1. CrCl3, CrBr3 and CrI3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 2.4.2. RhCl3, RhBr3 and RhI3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 2.4.3. RuCl3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 2.4.4. MoCl3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 3. Material and Methods 19 3.1. Chemicals and Substrates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 3.2. Synthesis, Purification and CVT of Materials . . . . . . . . . . . . . . . . . . . . . . 20 3.2.1. General Aspects of Preparation . . . . . . . . . . . . . . . . . . . . . . . . . 20 3.2.2. CrX3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 3.2.3. CrCl3-CrBr3 and CrBr3-CrI3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 3.2.4. RhX3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 X Table of Contents 3.2.5. RhCl3-RhBr3 and RhBr3-RhI3 . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 3.2.6. Purification of commercial RuCl3 . . . . . . . . . . . . . . . . . . . . . . . . 24 3.2.7. CrCl3-RuCl3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 3.2.8. MoCl3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 3.2.9. CrCl3-MoCl3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 3.2.10. Delamination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 3.3. Thermodynamic Simulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 3.3.1. Estimation of Unknown Thermodynamic Data . . . . . . . . . . . . . . . . 26 3.3.2. Simulations with Tragmin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 3.4. Instrumental Characterization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 3.4.1. Optical Microscopy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 3.4.2. Powder X-ray Diffraction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 3.4.3. Single-Crystal X-ray Diffraction . . . . . . . . . . . . . . . . . . . . . . . . . . 27 3.4.4. Scanning Electron Microscopy and Energy-Dispersive X-ray Spectroscopy 27 3.4.5. Transmission Electron Microscopy and Selected Area Electron Diffraction 28 3.4.6. Atomic Force Microscopy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 3.4.7. Raman Spectroscopy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 3.4.8. Infrared Spectroscopy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 3.4.9. Diffuse Reflection Spectroscopy . . . . . . . . . . . . . . . . . . . . . . . . . 29 3.4.10. Photoluminescence Spectroscopy . . . . . . . . . . . . . . . . . . . . . . . 30 3.4.11. X-ray Photoelectron Spectroscopy . . . . . . . . . . . . . . . . . . . . . . . 30 3.4.12. Inductively Coupled Plasma Optical Emission Spectroscopy . . . . . . . . 30 3.4.13. Simultaneous Thermal Analysis . . . . . . . . . . . . . . . . . . . . . . . . . 31 3.4.14. Electron Energy-Loss Spectroscopy . . . . . . . . . . . . . . . . . . . . . . . 31 3.4.15. Superconducting Quantum Interference Device Measurements . . . . . . 31 4. Results and Discussion 32 4.1. CrCl3 – CrBr3 and CrBr3 – CrI3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 4.1.1. Thermodynamic and CVT Simulations . . . . . . . . . . . . . . . . . . . . . 32 4.1.2. Solid Solution Synthesis and Basic Properties . . . . . . . . . . . . . . . . . 37 4.1.3. Structural Investigation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 4.1.4. Nanocrystal Growth, Enrichment Effects and Delamination . . . . . . . . . 45 4.1.5. Further Characterization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 4.2. RhCl3-RhBr3 and RhBr3-RhI3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55 4.2.1. Thermodynamic and CVT Simulations . . . . . . . . . . . . . . . . . . . . . 55 4.2.2. Solid Solution Synthesis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58 4.2.3. Thermochemical Investigation . . . . . . . . . . . . . . . . . . . . . . . . . . 59 4.2.4. Structural Investigation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62 4.2.5. Crystal Growth and Delamination . . . . . . . . . . . . . . . . . . . . . . . . 65 4.2.6. Further Characterization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70 4.3. CrCl3-RuCl3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73 4.3.1. Thermodynamic and CVT Simulations . . . . . . . . . . . . . . . . . . . . . 73 4.3.2. Solid Solution Synthesis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75 XI Table of Contents 4.3.3. Structural Investigation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76 4.3.4. Nanocrystal Growth, Enrichment Effects and Delamination . . . . . . . . . 78 4.3.5. Further Characterization of As-Grown Nanocrystals . . . . . . . . . . . . . 81 4.4. CrCl3-MoCl3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84 4.4.1. Thermodynamic and CVT Simulations . . . . . . . . . . . . . . . . . . . . . 84 4.4.2. Solid Solution Synthesis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87 4.4.3. Structural Investigation by pXRD . . . . . . . . . . . . . . . . . . . . . . . . . 88 4.4.4. Further Structural Characterization . . . . . . . . . . . . . . . . . . . . . . . 93 4.4.5. Magnetic Investigations of Powder Samples by SQUID . . . . . . . . . . . . 98 4.4.6. Summary of Characterization Results . . . . . . . . . . . . . . . . . . . . . . 101 4.4.7. CVT Experiments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102 5. Summary and Outlook 104 References 107 List of Figures 120 List of Tables 121 Abbreviations 122 Used Symbols 124 A. Appendix 126 A.1. Atom Positions and Space Group Transformations of 2D TMTH . . . . . . . . . . 126 A.2. Raw pXRD Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 128 A.3. Refined Lattice Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135 A.4. Additional Data of Characterizations . . . . . . . . . . . . . . . . . . . . . . . . . . . 138 A.5. EDX-Mappings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 141 A.6. Thermodynamic Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 144 / Die vorliegende Arbeit beschäftigt sich mit der Synthese und Nanokristallabscheidung von einigen ausgewählten Festkörperlösungen von Übergangsmetalltriahlogeniden mit 2-dimensionaler Kristallstruktur - konkret die Lösungen von CrCl3 – CrBr3, CrBr3 – CrI3, RhCl3 – RhBr3, RhBr3 – RhI3, CrCl3 – RuCl3 und CrCl3 – MoCl3. Dabei wurden theoretische Simulationen der Phasengleichgewichte und Partialdrücke angewandt um geeignete Synthesebedingungen für phasenreine Festkörperlösungen abzuschätzen und diese Synthesen im Anschluss entsprechend zu realisieren. Dabei zeigte sich, dass für die meisten der untersuchten Mischphasen spezielle Bedingungen, wie z.B. ein entsprechender Halogenüberschuss oder ein enges Temperaturfenster entscheidend für die erfolgreiche Synthese sind. Die Phasenreinheit der entsprechenden Produkte wurde mittels Röntgenpulverdiffraktometrie bestätigt. Diese Messungen wurden weiterhin zur Untersuchung des Verlaufs der Gitterparameter innerhalb der Mischungsreihen verwendet um potenzielle Abweichungen von idealem Mischungsverhalten der Randverbindungen beobachten zu können. Dabei zeigte sich für alle Mischungen außer CrCl3 – MoCl3 nur geringe oder keine Abweichungen von der Vegard’schen Regel. Für CrCl3 – CrBr3, CrBr3 – CrI3, RhCl3 – RhBr3, RhBr3 – RhI3 und CrCl3 – RuCl3 wurde das hergestellte Pulvermaterial mit verschiedenen Zusammensetzungen für die Abscheidung von hochqualitativen Nanokristallen auf einem Substrat verwendet. Dafür wurde die Methode des chemischen Gasphasentransports angewandt, wobei ebenfalls geeignete Abscheidungsbedingungen zuvor mittels Simulationen ermittelt wurden, bevor schlussendlich eine experimentelle Optimierung der Transportbedingungen durchgeführt wurde. Die damit erhaltenen 2D Nanokristalle weisen in der Regel Höhen im niedrigen 2-stelligen nm-Bereich auf, wobei im Fall von RhCl3 – RhBr3 auch direkt abgeschiedene Monolagen beobachtet wurden. Die Zusammensetzungen der abgeschiedenen Strukturen wurden intensiv mittels energiedispersiver Röntgenspektroskopie analysiert um mögliche Anreicherungseffekte der Festkörperlösungen während des Gasphasentransports zu detektieren. Dabei zeigte sich, dass eine Anreicherung insbesondere im Fall der kationischen Festkörperlösungen auftritt, während bei anionischen Lösungen ein kongruenter Transport vorherrscht. Mithilfe der Kenntnisse dieses Zusammenhangs lassen sich Nanokristalle mit kontrollierbarer Zusammensetzung über die entwickelte Methode abscheiden. Die hohe Qualität der abgeschiedenen Nanostrukturen wurde mittels Transmissionselektronmikroskopie, Feinbereichselektronenbeugung und Röntgenphotoelektronenspektroskopie sichergestellt. Je nach System wurden weitere ausgewählte Materialeigenschaften anhand von Pulver-Proben, bulk- oder Nanokristallen ermittelt, wie beispielsweise das Photolumineszenzverhalten der CrCl3 – CrBr3 und CrBr3 – CrI3 Reihen oder den Verlauf der optischen Bandlücke der RhCl3 – RhBr3 und RhBr3 – RhI3 Systeme. Anders als für die zuvor beschriebenen Systeme wurden im Fall von CrCl3 – MoCl3 starke Abweichungen von idealem Verlauf der Gitterparameter beobachtet, wobei innerhalb der Mischungsreihe mehrere Phasengebiete unterschieden werden können. Zur Erklärung dieser Anomalien wurden verschiedene Strukturmodelle erdacht, welche die Bildung von unterschiedlich angeordneten Mo-Mo-Dimeren innerhalb der Kristallstruktur beschreiben. Diese Hypothesen wurden mittels verschiedener Charakterisierungsmethoden wie z.B. IR-Spektroskopie oder SQUID-Messungen untersucht und im Rahmen der Aussagekraft der Messmethoden bestätigt. Die in dieser Arbeit entwickelten simulativen und experimentellen Methoden lassen sich auf zahlreiche ähnliche Systeme von Übergangsmetalltrihalogeniden übertragen, sind aber auch auf andere Verbindungsklassen anwendbar. Die damit verfügbar gemachten Nanokristalle sind für Folgeuntersuchungen im Hinblick auf die Eigenschaftsveränderungen bei der Nanoskalierung geeignet.:1. Introduction 1 2. Theoretical Background 3 2.1. Properties of Selected Transition Metal Trihalides and Their Solid Solutions . . . 3 2.1.1. Crystal Structures of 2D Transition Metal Trihalides . . . . . . . . . . . . . 4 2.1.2. CrX3 (X = Cl, Br, I) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 2.1.3. RhX3 (X = Cl, Br, I) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 2.1.4. RuCl3 and CrCl3-RuCl3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 2.1.5. MoCl3 and CrCl3-MoCl3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 2.2. Solid Solution Formation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 2.2.1. Structural Aspects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 2.2.2. Chemical Aspects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 2.2.3. Thermodynamic Aspects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 2.3. Chemical Vapor Transport . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 2.3.1. Bulk and Nanocrystal Growth by CVT . . . . . . . . . . . . . . . . . . . . . . 11 2.3.2. CVT of Solid Solutions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 2.3.3. Simulation of CVT Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . 13 2.4. Vapor Phase Chemistry of Selected Transition Metal Trihalides . . . . . . . . . . . 15 2.4.1. CrCl3, CrBr3 and CrI3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 2.4.2. RhCl3, RhBr3 and RhI3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 2.4.3. RuCl3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 2.4.4. MoCl3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 3. Material and Methods 19 3.1. Chemicals and Substrates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 3.2. Synthesis, Purification and CVT of Materials . . . . . . . . . . . . . . . . . . . . . . 20 3.2.1. General Aspects of Preparation . . . . . . . . . . . . . . . . . . . . . . . . . 20 3.2.2. CrX3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 3.2.3. CrCl3-CrBr3 and CrBr3-CrI3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 3.2.4. RhX3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 X Table of Contents 3.2.5. RhCl3-RhBr3 and RhBr3-RhI3 . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 3.2.6. Purification of commercial RuCl3 . . . . . . . . . . . . . . . . . . . . . . . . 24 3.2.7. CrCl3-RuCl3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 3.2.8. MoCl3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 3.2.9. CrCl3-MoCl3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 3.2.10. Delamination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 3.3. Thermodynamic Simulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 3.3.1. Estimation of Unknown Thermodynamic Data . . . . . . . . . . . . . . . . 26 3.3.2. Simulations with Tragmin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 3.4. Instrumental Characterization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 3.4.1. Optical Microscopy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 3.4.2. Powder X-ray Diffraction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 3.4.3. Single-Crystal X-ray Diffraction . . . . . . . . . . . . . . . . . . . . . . . . . . 27 3.4.4. Scanning Electron Microscopy and Energy-Dispersive X-ray Spectroscopy 27 3.4.5. Transmission Electron Microscopy and Selected Area Electron Diffraction 28 3.4.6. Atomic Force Microscopy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 3.4.7. Raman Spectroscopy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 3.4.8. Infrared Spectroscopy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 3.4.9. Diffuse Reflection Spectroscopy . . . . . . . . . . . . . . . . . . . . . . . . . 29 3.4.10. Photoluminescence Spectroscopy . . . . . . . . . . . . . . . . . . . . . . . 30 3.4.11. X-ray Photoelectron Spectroscopy . . . . . . . . . . . . . . . . . . . . . . . 30 3.4.12. Inductively Coupled Plasma Optical Emission Spectroscopy . . . . . . . . 30 3.4.13. Simultaneous Thermal Analysis . . . . . . . . . . . . . . . . . . . . . . . . . 31 3.4.14. Electron Energy-Loss Spectroscopy . . . . . . . . . . . . . . . . . . . . . . . 31 3.4.15. Superconducting Quantum Interference Device Measurements . . . . . . 31 4. Results and Discussion 32 4.1. CrCl3 – CrBr3 and CrBr3 – CrI3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 4.1.1. Thermodynamic and CVT Simulations . . . . . . . . . . . . . . . . . . . . . 32 4.1.2. Solid Solution Synthesis and Basic Properties . . . . . . . . . . . . . . . . . 37 4.1.3. Structural Investigation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 4.1.4. Nanocrystal Growth, Enrichment Effects and Delamination . . . . . . . . . 45 4.1.5. Further Characterization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 4.2. RhCl3-RhBr3 and RhBr3-RhI3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55 4.2.1. Thermodynamic and CVT Simulations . . . . . . . . . . . . . . . . . . . . . 55 4.2.2. Solid Solution Synthesis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58 4.2.3. Thermochemical Investigation . . . . . . . . . . . . . . . . . . . . . . . . . . 59 4.2.4. Structural Investigation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62 4.2.5. Crystal Growth and Delamination . . . . . . . . . . . . . . . . . . . . . . . . 65 4.2.6. Further Characterization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70 4.3. CrCl3-RuCl3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73 4.3.1. Thermodynamic and CVT Simulations . . . . . . . . . . . . . . . . . . . . . 73 4.3.2. Solid Solution Synthesis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75 XI Table of Contents 4.3.3. Structural Investigation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76 4.3.4. Nanocrystal Growth, Enrichment Effects and Delamination . . . . . . . . . 78 4.3.5. Further Characterization of As-Grown Nanocrystals . . . . . . . . . . . . . 81 4.4. CrCl3-MoCl3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84 4.4.1. Thermodynamic and CVT Simulations . . . . . . . . . . . . . . . . . . . . . 84 4.4.2. Solid Solution Synthesis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87 4.4.3. Structural Investigation by pXRD . . . . . . . . . . . . . . . . . . . . . . . . . 88 4.4.4. Further Structural Characterization . . . . . . . . . . . . . . . . . . . . . . . 93 4.4.5. Magnetic Investigations of Powder Samples by SQUID . . . . . . . . . . . . 98 4.4.6. Summary of Characterization Results . . . . . . . . . . . . . . . . . . . . . . 101 4.4.7. CVT Experiments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102 5. Summary and Outlook 104 References 107 List of Figures 120 List of Tables 121 Abbreviations 122 Used Symbols 124 A. Appendix 126 A.1. Atom Positions and Space Group Transformations of 2D TMTH . . . . . . . . . . 126 A.2. Raw pXRD Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 128 A.3. Refined Lattice Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135 A.4. Additional Data of Characterizations . . . . . . . . . . . . . . . . . . . . . . . . . . . 138 A.5. EDX-Mappings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 141 A.6. Thermodynamic Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 144

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Orientador: Franco Giuseppe Dedini / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica / Made available in DSpace on 2018-08-11T07:24:04Z (GMT). No. of bitstreams: 1 Saccheto_ThiagoJosedaSilva_M.pdf: 4654886 bytes, checksum: f2c656d8a1ed2a3a88bfd852d26a13d6 (MD5) Previous issue date: 2008 / Resumo: Neste trabalho, é apresentado um estudo dos parâmetros que influem na vida de uma CVT do tipo esfera-cone para aplicação em sistemas de tração humana, particularmente bicicletas. Nos primeiros capítulos, é apresentado um histórico sobre as transmissões e seus grupos principais e em seguida um breve resumo descrevendo os tipos de CVTs mais comuns encontrados no mercado, seu princípio de funcionamento e características principais. Após esse capítulo, é introduzida a teoria de contato de Hertz como forma de cálculo do perfil de pressão normal e o algorítmo de Kalker para o cálculo do perfil de pressão tangencial e slip. As equações de lubrificação também são estudadas nesse trabalho, a fim de determinar a espessura de filme lubrificante no contato da CVT. Por fim é apresentada a CVT do tipo esfera-cone Wagner Forti, na qual são discutidos suas características cinemáticas, dinâmicas e geométricas, além da simulação para um conjunto de condições de operação com o intuito de calcular a vida de contato com slip/spin. Finaliza-se o trabalho correlacionando o tempo de vida calculado com as condições de operação. Palavras Chave- CVT, Tempo de Vida, Contato, Slip, Spin / Abstract: In this work, a study of the parameters that influences the lifetime of a TrackBall CVT for use in systems of human traction, particularly bicycles. First, the mechanical transmissions history is told and mentioned its main groups. Then it presented a brief summary describing the types of CVTs most common in market, their principle of operation and main features. After this chapter, it introduces the theory of Hertz contact as way of calculating the normal pressure profile and, by Kalker algorithm, calculating the tangential profile with slip. The equations of lubrication are also studied in this work in order to determine the thickness of the lubricant film in the contact of CVT. Finally it shows the type of CVT TrackBall Wagner Forti, which is commented on its cinematic, dynamic and geometric features, and the simulation for a range of operating conditions in order to calculate the life of contact with slip/spin. Finally it is the work correlating the life calculated with the conditions of operation. Key Words:CVT, Lifetime, Contact, Slip, Spin / Mestrado / Mecanica dos Sólidos e Projeto Mecanico / Mestre em Engenharia Mecânica

With gas prices on the rise, the demand for high-mileage and low pollution vehicles has taken on an unprecedented role in our society. The production and implementation of electric and hybrid-electric vehicles has recently been a large focus of all major automobile manufacturers. Although these new vehicles have begun to solve much of the expensive fuel consumption and air pollution problems that our economy faces, the initial cost of these vehicles has proven to still be too expensive to capture a significant portion of the market. The further advancement of this technology must not only continue to focus on better fuel efficient and decreased pollution producing vehicles, but also decrease the cost of these vehicles to make them more available and enticing to the general public. Results from this research include one potential solution to reduce the cost of electric and hybrid-electric vehicles. Previous research performed in this area has led to the investigation and bench-top testing of a special type of mechanical system known as a Planetary Differential (PD). An exploration of the functionality of this system has shown that the PD can simplify expensive and complex electronic control systems for electric and hybrid-electric vehicles, thus reducing the cost to the consumer. In this study, fundamental speed, torque and power relationships for the PD were developed and tested under various loading conditions. Advantages and disadvantages of the PD, as compared to other similar mechanical systems, are identified and outlined. Recommendations for future work and implementation of the PD in electric and/or hybrid-electric vehicles are presented herein.

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Orientador: Júlio Carlos Teixeira / Dissertação (mestrado) - Universidade Federal do ABC. Programa de Pós-Graduação em Energia