Dissertations / Theses on the topic 'Non-conventional'

The interest on epoxidised vegetable oils has been increasing in the last years thanks to their use as renewable and sustainable resource for a wide range of environmental-friendly and sustainable chemicals. The aim of this work is producing epoxidised soybean oil in newer, safer and more efficient ways. This PhD thesis is structured according to different experimental approaches, supported by a kinetic and mass transfer modelling to enable a complete understanding of the phenomena. The epoxidation process was carried out in two phases via peroxyacetic acid, produced by the reaction between acetic acid and hydrogen peroxide. Epoxidation of soybean oil was carried out in a batch calorimetric reactor, for an accurate study on kinetics, mass transfer and calorimetry. Furthermore, the microwave (MW) heating effect on the process was studied, by means of a comparative study using two geometrically similar reactors with different heating sources, conventional and MW heating. MW heating process is able to produce a uniform stable suspension halving the time to reach maximum yield. Epoxidation was tested also in a continuous system, for its potential industrial interest. The process was also effective in a continuous reactor, even though the mixture must be stabilised by means of a surfactant. The feasibility of using radiofrequency heating in the continuous reactor was tested for more controlled operation than MW heating.

CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO
O objetivo deste trabalho foi avaliar as propriedades mecânicas, físicas e microestruturais de materiais compósitos cimentícios reforçados por fibras naturais e de laminados de bambu. O trabalho experimental foi direcionado para a determinação da tenacidade. Para se determinar a tenacidade foram utilizados três tipos de ensaios: impacto Charpy, impacto balístico e flexão em 3 pontos. Após os ensaios, a superfície de fratura dos corpos-de-prova foi analisada por microscopia eletrônica de varredura (MEV). Esta análise microestrutural serviu para determinar os modos de fratura e validar as hipóteses feitas nos modelos matemáticos utilizados. Foram usados modelos adaptados da literatura para a determinação da tenacidade e os valores teóricos obtidos foram confrontados com os experimentais. Determinou-se também através de modelos encontrados na literatura a tensão interfacial de todas as fibras utilizadas nesta pesquisa. Os modelos empregados para calcular a tenacidade e a tensão de adesão interfacial, se mostraram eficientes e válidos. Em segundo plano, porém não menos importante, ficou a determinação das propriedades térmicas dos materiais utilizados. Foram efetuados ensaios de condutividade térmica do compósito e ensaios termogravimétricos das fibras vegetais e do bambu. Os compósitos cimentícios foram reforçados por diferentes fibras naturais: polpa refinada de bambu (CPB), polpa de sisal (CPS), polpa de eucalipto (CPE), fibras curtas de sisal (CPFS) e wollastonita (CPW). As proporções das polpas de bambu, sisal e eucalipto utilizadas como reforço nas matrizes cimentícias foram de 8 por cento e 14 por cento em relação à massa do cimento, a da fibra curta de sisal (25 mm) foi de 3 por cento em relação ao volume e a da wollastonita foi de 11,5 por cento em relação à massa. Compóstios híbridos feitos com wollastonita e polpa de bambu (CPBW) foram também produzidos apenas variando a proporção da polpa de bambu em 8 por cento e 14 por cento e mantendo fixa a da wollastonita em 11,5 por cento. Como uma tentativa de se melhorar a resistência ao impacto, laminados CPB/AL foram também fabricados colando duas chapas de alumínio (liga 5052 H34) de espessura 0,8 mm em ambas às faces dos compósitos reforçados por fibra de bambu, formando assim compósitos sanduíche (CPBA). O bambu Moso (Phyllostachys heterocycla pubescens) com 5 anos de idade foi usado para fabricação dos laminados de bambu, sendo tratado com água fervida para a prevenção de ataques biológicos. Técnicas para a extração do laminado a partir de seu formato natural foram estudadas estabelecendo suas vantagens e desvantagens. Para o ensaio de impacto foram utilizados corpos-de-prova com dimensão nominal de 120 mm x 15 mm x 6 mm perfazendo um total de 18 corpos-de-prova. Para o de flexão foram realizados ensaios com uma lâmina simples de bambu (BL) e bambu laminado colado (BLC) com 3 camadas de lâminas dispostas ortogonalmente. Os resultados dos testes de impacto Charpy e flexão em 3 pontos comprovaram a boa tenacidade do bambu laminado quando submetido a cargas de impacto (42,54 kJ/m2) e a cargas estáticas (19,77 kJ/m2 para o laminado e 17,63 kJ/m2 para o laminado colado). Compósitos sanduíche constituídos de alumínio e laminados de bambu foram também fabricados. Estes foram analisados através de ensaios de impacto balísticos seguindo as recomendações da norma NIJ 0101.04. Observações no microscópico eletrônico de varredura foram realizadas para se analisar os mecanismos de falha dos laminados.
The main objective of this work was to evaluate the mechanical, physical and microestructure properties of cementitious composite materials and bamboo laminates. The experimental program was focused on the determination of toughness. Three diferent types of tests were performed in order to establish it: Charpy impact, ballistic impact and three point bending test. After the tests, the fractured surface of the failed test specimens was observed using a Scanning Electron Microscope (SEM) to establish the failure mode. Mathematical models adapted from the available literature were used to determine the toughness from which the values were confronted to the ones obtained experimentally. It was also determined by mathematical models the interfacial bond stress of all fibers used in this research. The two models, used in the toughness and interfacial bond stress calculation, showed to be efficient, providing valid results. In second plan, but not less important, was the determination of the materials thermal properties. Thermal conductivity tests of the composites and thermogravimetry of the fibers and bamboo were performed. The cementitious composites were reinforced by different natural fibers: refined bamboo pulp (CPB), sisal pulp (CPS), eucalyptus pulp (CPE), short sisal fibers (CPFS) and wollastonite. The mass fraction of bamboo, sisal and eucalyptus pulp studied were 8 percent and 14 percent. For the wollastonite fiber the mass fraction studied was 11.5 percent and for the short sisal fiber a 3 percent volume fraction was studied. Hybrid composites made with wollastonite and bamboo pulp (CPBW) were also produced varying the bamboo fraction mass to 8 percent and 14 percent but keeping constant to 11.5 percent the wollastonite mass fraction. The slurry de-watering process was used in the production of all composites described before. To reduce the adverse effects of weathering on the cellulose fibers and to improve the impact load and flexural resistance of the composite, aluminum thin sheets were used to produce a sandwich composite lamina with the CPB, which was denominated as CPBA. Compound Adhesive gel from Otto Baumgart which is a type of epoxy was used to fix the aluminum sheets on the CPB. The use of aluminum has proved to give much higher impact resistance results when compared to the CPB ones. The 5 years old Moso bamboo (Phyllostachys heterocycla pubescens), which was previously treated in boiled water to eliminate biological agents, was used to produce the bamboo laminates. Techniques were developed to extract bamboo laminates from its natural form, establishing its advantages and disadvantages. For the Charpy impact test, a total of 18 specimens with nominal dimensions of 120 mm x 15 mm x 6 mm were tested. Laminated (BL) and 3 layer cross ply laminated bamboo (BLC) were tested in bending. A total of 9 specimens were tested per bamboo configuration. The BL specimens had nominal dimensions of 120 mm x 30 mm x 6 mm and the BLC were 120 mm x 30 mm x 17 mm. The results demonstrated the good toughness of bamboo laminates when subject to dynamic (42.54 kJ/m2) and to static load (19.77 kJ/m2 for the laminate and 17.63 kJ/m2 for the cross ply laminate). Aluminum thin sheets were again used to make sandwich composites, but now using the bamboo laminate (BLCA). The BLCA was tested using the ballistic impact test following the standard NIJ 0101.04. Analysis on the Scanning Eléctron Microscope (SEM) were performed in order to establish the laminate s failure mechanisms.

The revolution in digital communications witnessed over the last decade had a significant impact on the world of Business Intelligence (BI). In the big data era, the amount and diversity of data that can be collected and analyzed for the decision-making process transcends the restricted and structured set of internal data that BI systems are conventionally limited to. This thesis investigates the unique challenges imposed by three specific categories of non-conventional data: social data, linked data and schemaless data. Social data comprises the user-generated contents published through websites and social media, which can provide a fresh and timely perception about people’s tastes and opinions. In Social BI (SBI), the analysis focuses on topics, meant as specific concepts of interest within the subject area. In this context, this thesis proposes meta-star, an alternative strategy to the traditional star-schema for modeling hierarchies of topics to enable OLAP analyses. The thesis also presents an architectural framework of a real SBI project and a cross-disciplinary benchmark for SBI. Linked data employ the Resource Description Framework (RDF) to provide a public network of interlinked, structured, cross-domain knowledge. In this context, this thesis proposes an interactive and collaborative approach to build aggregation hierarchies from linked data. Schemaless data refers to the storage of data in NoSQL databases that do not force a predefined schema, but let database instances embed their own local schemata. In this context, this thesis proposes an approach to determine the schema profile of a document-based database; the goal is to facilitate users in a schema-on-read analysis process by understanding the rules that drove the usage of the different schemata. A final and complementary contribution of this thesis is an innovative technique in the field of recommendation systems to overcome user disorientation in the analysis of a large and heterogeneous wealth of data.

L'industria 4.0 sta trasformando radicalmente i processi e i sistemi di produzione con l'adozione di tecnologie abilitanti, come l'Internet of Things (IoT), il Big Data, l'Additive Manufacturing (AM) e il Cloud Computing. I principi di queste tecnologie possono anche essere tradotti in qualsiasi aspetto della vita quotidiana grazie all'uso dell'elettronica stampata (PE), offrendo tecniche per produrre sensori e sistemi non convenzionali o per rendere "intelligenti" oggetti convenzionali. Con la PE a giocare un ruolo chiave nella progettazione di oggetti di nuova generazione, gli oggetti intelligenti adempiono alla loro funzione originale, e possono misurare quantità fisiche nell'ambiente circostante, essendo in grado di comunicare con altri oggetti o unità remote. Diverse tecnologie facenti parte della PE potrebbero essere adottate, ma soprattutto l'Aerosol Jet Printing (AJP) con le sue caratteristiche può essere considerata per tale scopo essendo in grado di stampare su qualsiasi tipo di superficie un'enorme varietà di materiali funzionali. In combinazione con il Flash Lamp Annealing (FLA), un processo termico a bassa temperatura, è possibile completare la produzione di sensori e circuiti su qualsiasi tipo di substrato. Lo scopo di questo lavoro di tesi è quello di identificare metodi e processi innovativi che permettano di incorporare direttamente sensori, circuiti ed elettronica sulla superficie degli oggetti e di analizzarne le caratteristiche metrologiche. A tal fine, sono stati effettuati studi di compatibilità considerando diversi materiali, sia in termini di substrati che di inchiostri per la realizzazione di sensori e oggetti intelligenti. Inoltre, è stata analizzata la progettazione, la fabbricazione e il test di sensori e circuiti in diversi campi. Il capitolo 1 fornirà il background e lo schema di questa tesi. Gli oggetti intelligenti possono essere fabbricati con numerose tecnologie e materiali diversi a seconda delle prestazioni richieste e dell'applicazione specifica. Lo scopo del capitolo 2 è di fornire un'analisi delle tecnologie di elettronica stampata 3D che permettono la stampa di sensori su superfici complesse. In primo luogo, viene fornita una spiegazione delle tecnologie in esame. Poi, concentrandosi sulle tecnologie utilizzate, verrà fornita un'analisi approfondita di AJP e FLA nel capitolo 3. Gli esempi svolti sono suddivisi in quattro macro-aree, dispositivi indossabili, packaging su carta, applicazioni di wet laboratory analysis (rilevamento di cellule e biomolecole), per dimostrare l'applicabilità delle metodologie proposte nella realizzazione di sensori e oggetti intelligenti. A partire dal capitolo 4 verranno riportati esempi applicativi. I prototipi testati sono stati coinvolti in diversi contesti lavorativi, dall'industria alimentare alla riabilitazione medica, passando per le analisi di laboratorio, mantenendo un tratto comune: misurare grazie a sensori non convenzionali. Questo fatto sottolinea l'applicabilità delle metodologie proposte a qualsiasi tipo di richiesta, dando la possibilità di trasformare gli oggetti quotidiani in oggetti intelligenti, dimostrando così la flessibilità dei metodi individuati e la pervasività dei sensori e degli oggetti intelligenti così realizzati.
Industry 4.0 has radically been transforming the production processes and systems with the adoption of enabling technologies, such as Internet of Things (IoT), Big Data, Additive Manufacturing (AM), and Cloud Computing. The principles of these technologies can be also translated into any aspect of everyday life thanks to the usage of printed electronics (PE), offering techniques to produce unconventional sensors and systems or to make conventional objects “smart”. With PE playing a key role in the design of next-generation objects, smart objects fulfill their original function, and they can measure physical quantities in the surrounding environment, being able to communicate with other objects or remote units. Many PE technologies could be adopted, but above all, Aerosol Jet Printing (AJP) with its characteristics can be considered for such a purpose being able to print on any kind of surface a huge variety of functional materials. In combination with Flash Lamp Annealing (FLA), a low-point temperature thermal process, it is possible to complete the production of sensors and circuits on any kind of substrate. The aim of this thesis work is to identify innovative methods and processes allowing to directly embed sensors, circuits and electronics on the surface of objects and to analyze the metrological characteristics. To this end, compatibility studies have been carried out considering different materials, both in terms of substrates and inks for the realization of smart sensors and objects. Furthermore, design, fabrication and test of sensors and circuits has been analyzed in different fields. Chapter 1 will provide the background and the outline of this dissertation. Smart objects can be manufactured with numerous different technologies and materials depending on the performance required and on the specific application. The purpose of chapter 2 is to provide an analysis of 3D PE technologies that enable sensors printing on complex surfaces. First, an explanation of the technologies under consideration is provided. Then focusing on the used technologies, a deep analysis of AJP and FLA will be provided in chapter 3. Examples carried out are divided into four macro-areas, wearable devices, paper-based packaging, wet laboratories applications (cells and biomolecules sensing), to demonstrate the applicability of the proposed methodologies in the realization of sensors and smart objects. Starting from chapter 4, applicative examples will be reported. The tested prototypes were involved in different working contexts, from food industry to medical rehabilitation, passing through laboratory analysis, keeping a common trait: measuring thanks to unconventional sensors. This fact underlines the applicability of the proposed methodologies to any kind of request, giving the possibility to turn everyday objects into smart ones, thus demonstrating the flexibility of the methods identified and the pervasiveness of sensors and smart objects made this way.

Non-conventional approaches are prime concerns for most design issues in nonlinear adaptive control and signal processing. During the last decade major advances have been made in the theory of Adaptive Systems. Due to the advantageous features of Soft Computing techniques, such as flexibility and robustness, they have become fundamental tools in many areas. These methods are suitable for solving problems that are highly nonlinear or when only partial, uncertain data is available. In such situations, the application of traditional approaches is often complicated and what is more, can not guarantee the expected performance level. Therefore, my primary aim is to reveal new ways to overcome this difficulty by using Soft Computing, non-conventional and novel data representation techniques. In this Thesis I address novel data representation and control methods that are able to adaptively cope with usually imperfect, noisy or even missing information (for instance, wavelet based multiresolution controllers, anytime control, Situational Control, Robust Fixed Point Transformation (RFPT)-based control). The great majority of the adaptive nonlinear control design are based on Lyapunov’s 2nd or commonly referred to as the “Direct” method. The major defect of this method that it is mathematically complicated and it works with a large number of arbitrary adaptive control parameters. Moreover, the parameter identification process in certain cases is vulnerable if unknown external perturbations can disturb the system under control, etc. In the recent years the RFPT has been introduced for replacing the Lyapunov technique. Since, in this Thesis my first intention was to deal with the possibilities of the combination of classical model identification and the RFPT-based design in depth. I have proposed a new method that utilize the geometric interpretation provided by the Lyapunov-technique that can be directly used for parameter tuning. I have shown that these useful information can be obtained on the actual parameter estimation error by using the same feedback terms and equations of motion as the original methods. In order to improve the parameter tuning process, I have suggested the application of the Modified Gram-Schmidt Algoritm for the possible combination of the RFPT-based method with the Modified Adaptive Inverse Dynamic Robot Controller (MAIDRC) and the Modified Adaptive Slotine-Li Robot Controller (MADSLRC). Besides, I have presented an even simpler tuning technique in the case of the Modified Adaptive Inverse Dynamics Robot Controller that also applies fixed point transformation-based tuning rule for parameter identification. Afterwards, I have presented a systematic method for the generation of a new family of the Fixed Point Transformations, the so-called „Sigmoid Generated Fixed Point Transformation (SGFPT)” for the purpose of „Adaptive Dynamic Control” for nonlinear systems. At first, I have outlined the idea for the „Single Input - Single Output (SISO)” systems, then I have shown that it can be extended to „Multiple Input – Multiple Output (MIMO)” systems. Additionally, I have replaced the tuning method by a simple calculation in order to further simplify and improve the method. I have proposed new advances regarding the SGFPT. Also, I have described a new control strategy based on the combination of the “adaptive” and “optimal” control by applying time-sharing strategy in the SGFPT method, that supports error containment by cyclic control of the different variables. Further, I have introduced new improvements on the SGFPT technique by introducing “Stretched Sigmoid Functions”. The efficiency of the presented control solution has been confirmed by the adaptive control of an underactuated mechanical system. I have investigated the applicability of fuzzy approximation in the SGFPT-type control design and demonstrated the usability via simulation investigations. Furthermore, I have shown a new type of function for the adaptive deformation in the SGFPT. The other important issue that includes the maintenance of unwanted sensor noises that are mainly introduced by feedback into the system under control. Therefore, in the development of a control system the signals of noisy measurements has to be addressed first so that more sophisticated signal pre-processing methods are required. Since, I have concerned the issue of well-adapted techniques for smoothing problems in the time domain and fitting data to parametric models. In a wider sense this means, that research is also needed to determine novel approximations that can be used for smoothing the operation of the adaptive controller. After, I have investigated the Savitzky-Golay (SG) smoothing and differentiation filter. It has been proven that the performance of the classical SG-filter depends on the appropriate setting of the windowlength and the polynomial degree. The main limitations of the performance of this filter are the most conspicuous in processing of signals with high rate of change. In order to overcome this limitation I have developed a new adaptive method to smooth signals based on the Savitzky-Golay algorithm. The provided method ensures high precision noise removal by iterative multi-round smoothing. The signal approximated by linear regression lines and corrections are made in each step. Also, in each round the parameters are dynamically change due to the results of the previous smoothing. For supporting high precision reconstruction I have introduced a new parametric weighting function. Thesis applications and proof of operation have been confirmed by numerical simulations.

This thesis is concerned with understanding the effect of diols on emulsion properties and to use knowledge gained to optimise emulsions containing them. The project was sponsored by GlaxoSmithKline, a world leading pharmaceutical company, whose interest is in using the knowledge to help in research and development of new products and optimising existing products during manufacture. For this reason pharmaceutical ingredients were used throughout unless additional knowledge could be gained from using non-pharmaceutical ingredients. Systems studied included emulsions with water, diols and paraffin liquid stabilised by surfactants and particles using various techniques from microscopy, conductivity, surface tension, rheology, light scattering, stability analysis, differential scanning calorimetry and nuclear magnetic resonance. The thesis will examine three aspects of emulsion non-conventionality; addition of diol to both surfactant and particle-stabilised emulsions and the effect of crystallisation in diol containing emulsions stabilised solely by surfactant. Surfactant and particle-stabilised systems will be discussed in terms of phase inversion where it will be shown that inversion of emulsions can be controlled by addition of diol within both systems. For phase inversion in water, diol, paraffin liquid and non-ionic surfactant systems it will be argued that the phase inversion witnessed is due to the change in preferred surfactant monolayer curvature. This will be shown by examining the structurally and isomeric nature of the diols as well as their surface activity. Also considered and compared will be the well established experimental facts that occur in related systems at phase inversion including initial droplet diameter, emulsion stability, temperature variation and surfactant structure change. Results will show that for all traits examined at phase inversion diol addition follows all well known facts regarding a change of preferred surfactant monolayer curvature from negative to positive values. Emulsions stabilised by particles will be shown to phase invert from w/o to o/w emulsions with the addition of diol and changing particle hydrophobicity at fixed hydrophobicity and fixed diol content respectively. This will be contributed to the surface energies of each system and therefore a decrease in contact angle θ with increasing diol addition and changing hydrophobicity. Included will be a comparison between calculated and measured phase inversion of a number of diol containing series which shows good correlation. Systematic studies will also include the effect of this phase inversion on droplet diameter, stability and emulsion type. These will be explained in terms of existing theory regarding particle stabilised emulsions. Diol effect on the in situ contact angle will also be shown in water/diol–air mixtures. Investigations will include the immersion times of fumed silica powders of varying wettability in water-propane-1,2-diol mixtures and from theory the contact angles of particles at the air-polar phase interface will be determined. The materials formed upon aerating these samples will also be described in terms of the wettability of the particles in situ. Again the result will indicate that diol increase the inherent hydrophilicity of the system and therefore change the materials formed upon aeration. The final chapter of the thesis will discuss the effects of crystallisation in emulsions containing diol stabilised solely by surfactant. Crystallisation with surfactant stabilised systems will be discussed in terms of changing temperature and varying droplet diameter of emulsions. It will be shown that droplet diameter has an effect on the crystallisation of dispersed oil droplets and linked to stability. Systemic investigations using differential scanning calorimetry, rheology and nuclear magnetic resonance will show the crystallisation effect of a model system and attempts to link such findings to stability and the crystallisation mechanism. Microscopy of an additional model system containing high amounts of diol will show the ability of such systems to produce ‘dumbbell’ droplets when the systems temperature is decreased. Additional discussion on the formation of dumbbells and the effect on stability in diol containing emulsions will also be considered.

Les humains sont en mesure d’interpréter l’environnement qui les entourent avec peu d’effort grâce à système visuel très performant. Par analogie, un système de vision capable de recueillir les mêmes informations sur l’environnement est hautement souhaitable en robotique autonome pour effectuer des tâches complexes et ainsi interagir avec les humains.À cet égard, nous nous sommes particulièrement intéressés aux environnements intérieurs, dans lesquels les humains passent presque toute leur vie. Dans ce travail, pour faire une analyse efficace et rapide des scènes, nous avons opté pour l’utilisation de caméras non conventionnelles : l’imagerie 360° et les capteurs 3D. Ces systèmes ont la particularité d’acquérir en une seule prise de vue soit la totalité de l’environnement qui entoure le robot (caméras 360°) soit l’information 3D.C’est ainsi que cette thèse aborde les problèmes de description hiérarchique d’une scène d’intérieur avec des capteurs non conventionnels allant de l’estimation de la disposition des pièces ; de la détection et la localisation des objets à la modélisation de la forme des objets 3D.Ces différents points font l’objet de contribution dans ce travail. Dans un premier temps, nous nous sommes intéressés à l'estimation de la disposition 3D de la pièce à partir d'une seule image à 360°. Pour ce faire, nous exploitons l'hypothèse de Manhattan World et les techniques d'apprentissage profond pour proposer des modèles qui gèrent les parties occultées de la pièce sur l'image. A vu de la particularité des images considérées, nous avons développé de nouveaux filtres de convolution d’image tenant compte des fortes distorsions des images équirectangulaires.Par la suite, et dans l’objectif de permettre au robot de faire une analyse contextuelle de hauts niveaux de la scène qui l’entoure, nous nous sommes intéressés au problème de la localisation et de la segmentation des objets. C’est ainsi que nous avons une nouvelle fois exploité les images 360° en tenant compte de la disposition des objets 2D dans l’image dans le but de les décrire par leur modèle 3D en adéquation avec la disposition de la pièce préalablement estimée.La dernière contribution de ce travail tire parti des capteurs 3D pour étudier la forme des objets. Dans ce cadre, nous utilisons une modélisation explicite de la non-rigidité de objets et caractérisons leurs symétries afin de détecter, par un apprentissage profond non supervisé, ces points d’intérêt 3D.Toutes ces contributions nous ont permis de faire progresser l’état de l’art sur les problèmes posés et ont toutes fait l’objet d’évaluation sur des bases de données de référence dans notre communauté
Humans understand environments effortlessly, under a wide variety of conditions, by the virtue of visual perception. Computer vision for similar visual understanding is highly desirable, so that machines can perform complex tasks by interacting with the real world, to assist or entertain humans. In this regard, we are particularly interested in indoor environments, where humans spend nearly all their lifetime.This thesis specifically addresses the problems that arise during the quest of the hierarchical visual understanding of indoor scenes.On the side of sensing the wide 3D world, we propose to use non-conventional cameras, namely 360º imaging and 3D sensors. On the side of understanding, we aim at three key aspects: room layout estimation; object detection, localization and segmentation; and object category shape modeling, for which novel and efficient solutions are provided.The focus of this thesis is on the following underlying challenges. First, the estimation of the 3D room layout from a single 360º image is investigated, which is used for the highest level of scene modelling and understanding. We exploit the assumption of Manhattan World and deep learning techniques to propose models that handle invisible parts of the room on the image, generalizing to more complex layouts. At the same time, new methods to work with 360º images are proposed, highlighting a special convolution that compensates the equirectangular image distortions.Second, considering the importance of context for scene understanding, we study the problem of object localization and segmentation, adapting the problem to leverage 360º images. We also exploit layout-objects interaction to lift detected 2D objects into the 3D room model.The final line of work of this thesis focuses on 3D object shape analysis. We use an explicit modelling of non-rigidity and a high-level notion of object symmetry to learn, in an unsupervised manner, 3D keypoints that are order-wise correspondent as well as geometrically and semantically consistent across objects in a category.Our models advance state-of-the-art on the aforementioned tasks, when each evaluated on respective reference benchmarks

Synchronous reluctance (SyR) and Permanent magnet Synchronous Reluctance (PM-SyR) machines represent an answer to the growing emphasis on higher efficiency, higher torque density and overload capability of ac machines for variable-speed applications. Their high performance is particularly attractive in electric traction and industry applications. The SyR technology represents a convenient solution to obtain high efficiency machines at reduced cost and high reliability. The manufacturing costs are comparable to other existing technologies such as induction motors. Different SyR and PM-SyR machines with different ratings and applications were designed, for comparison with induction motors having equal frame. An accurate comparison between Induction motors, SyR and PM-SyR machines is reported, with reference to the IE4 and IE5 efficiency specifications that could become mandatory in the next years. Three studies are classified under the term ”Non-Conventional” machines: Line-Start SyR motor: is a special SyR machine designed for constant speed applications, line supplied. The rotor flux barriers are filled with aluminum, to obtain a squirrel cage that resembles the one of an induction motor. The manufacturing costs are comparable to those of the induction motor, and the efficiency is higher. Two prototypes were realized and tested. FSW-SyR: tooth-wound coils and fractional slot per pole combinations were investigated. They are of interest because they permit a simplification and higher degree of automatization of the manufacturing process. However, FSW-SyR machines are known for their high torque ripple, low specific torque and power factor. The number of slots per pole was optimized to maximize the torque density. Dealing with the torque ripple, a lumped parameters model was used together with optimization in SyRE. A design with minimized ripple was obtained, comparable to a distributed winding machine in this respect. This design was prototyped and tested. Mild Overlapped SyR: this study shows a new winding configuration applied to SyR and PM-SyR machines. The proposed case is in the direction to find a hybrid solution between distributed winding and tooth winding motors, that permits to reduce costs and improve performances. One limitation of this solution is that only number of pole pairs equal to five or higher are feasible, and this reduces the applicability of the solution to classical industry applications, where one to three pole pairs are normally used.

Sustainability is one of the most pressing challenge of our century, this term is becoming a main keyword of political agendas and more in general of mass media. To increase the “greenness of bioprocesses”, academia and industry, especially in the biotechnological and chemical fields, are focusing their studies with the scope to shift from traditional organic synthesis to new processes with reduced ecological foot-print. A good way to increase sustainability could be set up bioprocesses exploiting microorganisms. Nowadays, companies are searching new organisms that, differently from the well characterized Saccharomyces cerevisiae, show to be more resistant to the harsh conditions commonly occurring in industrial fermentations (high salt concentration, temperature and pressure). Due to their peculiar features, non-conventional yeasts (NCYs) seem to be a promising solution. On the other hand, the disadvantage to use these new organisms is related to the few studies and literature data available, especially compared to S. cervisiae. To fill this gap researchers have started to characterize these new species. My PhD work had dual aim: • First to identify good candidates, with specific physiological properties, that could be exploited in bioprocesses. • Second to characterize new promising enzymatic activities useful for industrial applications. In the first studies, I focused my attention on marine yeasts. I chose yeasts isolated from this environment, because their use gives the possibility to perform a seawater-based bioprocess saving large amount of fresh waters, reducing both cost and environmental impact. From our laboratory yeasts collection, I selected, for their halotolerance, two different Debaryomyces hansenii strains. Hence mechanisms involved in osmotic stress response have been investigated employing flow cytometry. I showed that hyper-osmotic stress elicits membrane depolarization and decreases membrane permeability to cationic compounds. This phenomenon reduces ions permeability and can negatively affect the uptake of charged substrate during bioprocesses. My research proceeded with the set up of new fermentation protocols in seawater-based media composed by a mixture of hexose and pentose sugar and cheap nitrogen sources. In these conditions we obtained high biomass yield (0.627) in 40 h of bioprocess. In the second part of my PhD project, I studied NCYs as sources of enzymes. With this aim I identified a nitrilase of marine strain of Meyerozyma guilliermondii, that displayed high activities on aromatic substrate, but also on arylaliphatic and aliphatic ones. These activities were maintained also in presence of high salts concentration. In particular M. guilliermondii nitrilase was able to perform complete dynamic resolution of mandelonitrile in seawaters within in 8 h. In the last part of my PhD, I identified a novel extracellular and cell-bound phytase activity in Cyberlindnera jadinii. This enzyme is suitable as feed additive, indeed activities at pH 4.5 and 37°C (animals gastric pH and temperature) were 26.25 mU/mgd.w. and 58.36 mU/mgd.w., detected as extracellular and cell-bound respectively. Phytase activities had their optimum at 50°C, reaching 37.2 mU/mgd.w. (extracellular) and 146 mU/mgd.w. (cell-bound). Data reported in my PhD work suggest that could be interest to proceed with further characterization on NCYs. New “green” bioprocesses characterized by high productivity could be a key for reach sustainability reducing the ecological impact of industrial production.

The international financial crisis naturally prompts the question of whether IIFS are robust and resilient or may be swept into crisis by a global wave and if so through what channels. This thesis considers channels through which the world financial crisis would affect IIFS, their features that may help contain it and those that may foster post crisis recovery in a dual banking system. Our sample covers 467 conventional banks and 90 Islamic banks in 16 countries for the period 2000-2008, a range advanced economies and emerging markets. We estimation the financial stability (z-score) in conventional and Islamic banks. The z-score has become a popular measure of bank soundness (Boyd and Runkle, 1993; Maechler, Mitra, and Worrell, 2005; Beck and Laeven, 2006; Laeven and Levine, 2006; Hesse and Čihák, 2007, 2008, 2010; Mercieca, Laeven and Levine, 2009; Beck; Demirgüç-Kunt and Merrouche, 2010). With a robust and a quantile estimation model, this empirical analysis explores causes of insolvency risk in Islamic and conventional banks in Middle East and North Africa (MENA) and Southeast Asian countries, by controlling for various factors, bank-by-bank data, macroeconomic and other system-wide indicators.

The work of this dissertation is centered on two non-conventional synthetic approaches to ferromagnetic nanomaterials: high-throughput experimentation (HTE) (polyol process) and continuous flow (CF) synthesis (aqueous reduction and the polyol process). HTE was performed to investigate phase control between FexCo1-x and Co3-xFexOy. Exploration of synthesis limitations based on magnetic properties was achieved by reproducing Ms=210 emu/g. Morphological control of FexCo1-x alloy was achieved by formation of linear chains using an Hext. The final study of the FexCo1-x chains used DoE to determine factors to control FexCo1-x, diameter, crystallite size and morphology. [Ag] with [Metal] provide statistically significant control of crystallite size. [OH]/[Metal] predict 100 % FexCo1-x at > 30. To conclude section 1, a morphological study was performed on synthesis of Co3-xFexOy using the polyol process. Co3-xFexOy micropillars were synthesized at various sizes. The close proximity of the particles in the nanostructure produced an optical anisotropy and was magnetically induced which is evidence for the magneto-birefringence effect. The second non-conventional synthetic approach involves continuous flow (CF) chemistry. Co nanoparticles (Ms=125 emu/g) were newly synthesized by aqueous reduction in a microreactor and had 30 ±10 nm diameter and were produced at >1g/hr, a marker of industrial-scale up viability. The final work was the CF synthesis of FexCo1-x. The FexCo1-x was synthesized with limitation to the composition. The maximum FexCo1-x phase composition at 20 % resulted from the aqueous carrier solvent triggering oxide formation over FexCo1-x.

Orientadora: Profa. Dra. Raquel de Almeida Ribeiro
Dissertação (mestrado) - Universidade Federal do ABC, Programa de Pós-Graduação em Física, 2017.
Em Física da Matéria Condesada, as terras raras apresentam um papel importante em várias aplicações tecnológicas. Suas camadas 4f incompletas possuem enumeras con- gurações diferentes possibilitando o desenvolvimento e melhoramento de propriedades interessantes. Materiais supercondutores, lasers de estado sólido, radares e ímãs permanentes são bons exemplos de dispositivos que utilizam materiais desenvolvidos com terras raras. Quando terras raras são colocadas em um material matriz, as interações entre esses elementos ou entre a matriz e as terras raras fazem com que os seus estados eletrônicos mudem. Estruturas cristalinas apresentam campo elétrico cristalino, cuja teoria desenvolvida no século passado foi amplamente estudada e aplicada à vários grupos de simetria em cristais bulk. Até o momento, porém, muito pouco tem sido estudado a respeito de como o campo elétrico de estruturas não convencionais, como quasicristias e nanocristais, afeta os autoestados das terras raras. Portanto, o objetivo desse projeto foi analizar o efeito de campo elétrico cristalino em dois tipos de materiais: Nanopartículas cúbicas com tamanho de 8 nm e quasicristais icosaédricos, bem como seu aproximante. Para isso, nanopartículas de NaY1..xRExF4 (RE = Yb, Er, Dy, Gd) foram sintetizadas pelo método de termo-decomposição e quasicristais de Au-Al-Yb foram crescidos em forno a arco. Para a determinação parâmetros de campo elétrico cristalino Bm n , foram feitos ajustes das curvas de magnetização dependentes da temperatura e do campo magnético aplicado. Além disso, para os quasicristais foi encontrado um grupo de simetria pontual equivalente e seus parâmetros de campo elétrico cristalino foram comparados com os de seus aproximantes. Com isso, observou-se que somente parâmetros de segunda ordem apresentaram uma diferença signicativa quando comparados entre essas duas estruturas; B0 2 é 20 vezes maior para a estrutura quasicristalina. Para as nanopartículas cúbicas, uma Hamiltoniana total foi proposta e com isso foi feita um simulação para determinar a separação total dos níveis de energia da camada incompleta 4f das terras raras. Além disso, o espectro de Up conversion foi medido e comparado com a simulação teórica. A largura de linha do espectro teórico, 470 20 K, para a transição 4S3=2 ! 4I15=2 , é comparável aos resultados empíricos, 650 50 K. O estado fundamental dos sistemas foi conrmado pela técnica de Ressonância Eletrônica de Spin. Dessa forma, foi estabelecida uma realação de como a separação total dos multipletos-J afeta a emissão de Up conversion destas NP's.
In Condensed Matter Physics, rare earth elements play an important role in several technological applications. Their complex 4f unfullled shell presents numerous dierent congurations, making possible to engineer or tune interesting properties. Superconductors, solid state lasers, radars and permanent magnets are some examples of cutting edge devices using materials developed with rare earth elements. When a rare earth ion is placed in a host material, their interactions with each other or with the host lattice are responsible for the arrangement of their electronic state. Crystalline structures exhibit the crystal eld eect, whose theory developed in the last century has been largely applied and studied to various point group symmetries in bulk crystals. However, there is a lack of researches in how the electric eld of non-conventional host lattices, such as quasicrystals and nanocrystals, aect rare earth's eigenstates. Therefore, the aim of this project was to analyze the crystal eld eect in two dierent kind of materials: Cubic nanoparticles with 8 nm in size and icosahedral bulk quasicristals, as well as their crystal approximant. For that, NaY1..xRExF4 (RE = Yb, Er, Dy, Gd) nanoparticles were synthesized by temperature decomposition and Au-Al- Yb quasicrystals were grown by arc-melting. Fittings of the thermal and eld dependent magnetization were used to determine the crystal electric eld parameters Bmn . In the quasicrystal material case, an equivalent point group symmetry was obtained and their crystal electric eld parameters were compared with the ones of their approximant. Only parameters of second order substantially diered between both structures, B02 was found out to be around 20 times larger than that for the approximant. Moreover, in the cubic nanostructures case, the overall splitting of the 4f unfullled shell of the RE elements was determined diagonalizing a proposed total Hamiltonian, whose terms include the Crystal Electric Field parameters. In addition, the up-conversion light emission signal was acquired and compared with a theoretical simulation. The theoretical up-conversion light emission line-width found out as 471 20 K, for the transition 4S3=2 ! 4I15=2 , is comparable to empirical results, 650 50 K. The ground state of the systems was conrmed by Electron Spin Resonance analysis. In this case, a relation with how the overall energy splitting of the J-multiplets aect the UC conversion light emission of theses NP's was established.

This thesis collects several ecotoxicological studies focused on the quali- quantitative analysis of several classes of chemical compounds. Our studies have been conducted on different aquatic species occupying different food chain trophic levels and characterized by differences in biology, ethology, and nutrition, but all considered excellent bioindicators. This choice allowed us to have a broad overview of the contamination of aquatic environments. Detrimental effects of several chemical compounds on the species investigated have been discussed, considering the economic and public health implications linked to the pollution of the environment and the exposure to old and emerging xenobiotics. Our studies underline the importance of a multidisciplinary and integrated approach that includes the application of the one health concept to ensure the protection of public health and respect for natural environments. Studies collected in this thesis also aim to overcome some critical limitations of the branch of ecotoxicology, such as the lack of standardization in laboratory methods. Our data also underline the importance of expanding research to a greater number of various biological matrices than those indicated by the literature as target tissues for specific pollutants. This condition enables more detailed information on the kinetics of xenobiotics in animal organisms. Our studies also allow us to expand the knowledge related to the mechanisms of synergy and antagonism of mixtures of pollutants that can simultaneously accumulate in wildlife.
Questa tesi raccoglie diversi studi ecotossicologici, che implicano una analisi quali-quantitativa relativa alla detezione di diverse classi di inquinanti su diverse specie acquatiche, che occupano differenti livelli trofici della catena alimentare, e che sono caratterizzati da differenze biologiche, etologiche e dietetiche, ma tutti considerati eccellenti bioindicatori. Questa scelta ci ha permesso di avere un'ampia panoramica della contaminazione degli ambienti acquatici. Sono stati discussi gli effetti dannosi di diversi composti chimici sulle singole specie in esame, considerando anche le implicazioni economiche e relative alla tutela della salute pubblica legate all'inquinamento dell'ambiente e all'esposizione a xenobiotici conosciuti ed emergenti. I nostri studi sottolineano l'importanza di un approccio multidisciplinare e integrato che includa l'applicazione del concetto di One Health per garantire la protezione della salute pubblica e il rispetto degli ambienti naturali. Gli studi raccolti in questa tesi mirano anche a superare alcuni importanti limiti della branca dell'ecotossicologia, come la mancanza di standardizzazione nelle metodiche laboratoristiche. I nostri dati sottolineano anche l'importanza di espandere la ricerca a un numero maggiore di matrici biologiche diverse rispetto a quelle indicate dalla letteratura come tessuti bersaglio per specifici inquinanti. Questa condizione consente di ottenere informazioni più dettagliate sulla cinetica degli xenobiotici negli organismi animali. I nostri studi permettono anche di ampliare le conoscenze relative ai meccanismi di sinergia e antagonismo delle miscele di inquinanti che possono accumularsi contemporaneamente nella fauna selvatica.

The presence of microbial commensals in the gut requires the establishment of a complex network of reciprocal interactions between the microbiota and the host immune system to allow nutrient absorption while preventing undesired mucosal immune responses. Despite these homeostatic mechanisms, during intestinal inflammation alterations of the microbiota composition, namely dysbiosis, trigger abnormal immune responses. Here, we aimed at investigating the functional crosstalk between gut microbiota and the mucosal immune system during inflammation and upon induction of microbial dysbiosis. We observed that inflammation-induced and antibiotic-driven types of dysbiosis are phenotypically and functionally modifying CD4+ T and iNKT cells activity. Moreover, during intestinal inflammation, the experimental manipulation of the microbiota community through Faecal Microbiota Transplantation (FMT) reduces colonic inflammation and initiates the restoration of intestinal homeostasis through the induction of IL-10 production by immune cells. Further, we performed a comprehensive analysis on intestinal iNKT cells isolated from surgical specimens of active Inflammatory Bowel Disease (IBD) patients and non-IBD donors. We report that the exposure to mucosa-associated microbiota drives iNKT cell pro-inflammatory activation, inducing direct pathogenicity against the intestinal epithelium. Collectively, we provided solid evidence that a strict crosstalk between the gut microbiota and the intestinal conventional and non-conventional T cells exists. Antibiotic-associated dysbiosis has immunostimulatory functions. Moreover, FMT can therapeutically control intestinal experimental colitis and this poses FMT as a valuable therapeutic option in immune-related pathologies. In addition, we generated fundamental knowledge about the pathogenic functions exerted by human intestinal iNKT cells upon the interaction with mucosa-associated microbiota communities.

Non-conventional techniques for polymerization and depolymerization were investigated. The rates of polymerization were enhanced higher in ultrasonic, supercritical fluids and microwaves. However in these system under certain conditions, simultaneous degradation also occurred. Depolymerization was studied by various methods like thermal degradation in supercritical fluids and in presence of oxidizers, Lewis acid and other organic acids. Degradation by ultrasound and thermal degradation of polymer mixtures were also investigated. The scission of the polymer backbone is random for thermal degradation while the scission occurs at the midpoint for ultrasonic degradation. The degradation rates in all the investigated techniques were higher than the degradation rates observed for pyrolysis. Degradation was possible at low temperature (< 50°C) for oxidative and ultrasound degradation while the degradation rates were two orders of magnitude higher in supercritical conditions. The molecular weight distribution was obtained by GPC analysis and the continuous distribution models were used to obtain the rate coefficients. The activation energies were calculated from the temperature dependence of the rate coefficients.

The aim of this thesis is to investigate structure-property relationships in several types of non-conventional liquid crystalline materials. First, supramolecular hydrogen bonded complexes involving either acid or phenol-based donors with pyridyl-based acceptors were studied using FT-IRM. These studies were made to investigate the nature and temperature dependence of the hydrogen bond between the donor and acceptor moieties. Second, a study of carbohydrate liquid crystals was undertaken. In this investigation two different types of carbohydrate-based materials were synthesised; (a) a homologous series of mono-tailed carbohydrates, the methyl-6-O-(n-acyl)-a-D-glucopyranosides were prepared to study the effect of alkyl chain length on phase behaviour and to elucidate how stereochemistry and the position of the alkyl chain affects liquid crystallinity; (b) a novel non-symmetric dimer containing a methoxyazobenzene moiety and a carbohydrate headgroup to study the behaviour of a dimer consisting of two incompatible mesogenic groups. Third, the effect of terminal alkyl chain branching on the molecular organisation in the intercalated smectic. A phase, was studied with a view to exploring the nature of the driving force for smectic phase formation in symmetric and non-symmetric liquid crystal dimers. The symmetric dimer chosen was 4.060.4, while the non-symmetric dimer was CB.060.4. In both systems the n-butyl terminal chains were replaced by either sec-butyl or tert-butyl chains. To establish how these structural changes effect smectic phase formation, binary phase diagrams of n-butyl-based compound with the corresponding branched material have been constructed. Finally, a comparison of the mesogenic properties of a series of monomers, dimers and side-chain liquid crystal polymers containing a methoxyazobenzene mesogenic unit was made. There data were used to examine the virtual trimer model as a means of rationalising the mesogenic behaviour of the polymers.

Abstract There is concern whether cabbage and beetroot wastes from the Fresh Produce Market are safe for feeding animals given the fact that some will have been discarded at the onset of putrefaction. This study evaluated the effects of sun-drying on microbiological load (E. coli, coliform, yeast and moulds and total bacterial count) in waste vegetables from the fresh produce market, since smallholder farmers tend to use the by-products without processing given the opportunity. Cabbage and beetroot wastes were sun dried to 14% moisture and micro-organisms were enumerated on both wet and dried samples. The results showed that sun drying reduced the level of micro-organisms significantly in both cabbage and beetroot. Although microbial load varied from batch to batch in the wet samples, coliforms were significantly more abundant in wet beetroot than in the dried samples. However, dried beetroot contained significantly more yeast and moulds. Wet cabbage contained more coliform and yeast and moulds compared to sun-dried cabbage. The sun drying process is thus an efficient processing method for resource poor farmers to reduce the microbial load in these animal feed sources and improve their shelf life.

Retweets are an important mechanism for the propagation of information on the Twitter social media platform. However, many retweets do not use the offcial retweet mechanism, or even community established conventions, and these "dark retweets" are not accounted for in many existing analyses. In this thesis, a typology of 19 different tweet propagation types is presented, based on seven characteristics: whether it is proprietary, the mechanism used, whether it is created by followers or non-followers, whether it mentions other users, if it is explicitly propagating another tweet, if it links to an original tweet, and the audience that it is pushed to. Based on this typology and two retweetability confidence factors, the degrees of a retweet's "darkness" can be determined. This typology was evaluated over two datasets: a random sample of 27,146 tweets, and a URL drill-down dataset of 262,517 tweets. It was found that dark retweets amounted to 20.8% of the random sample, however the behaviour of dark retweets is not uniform. The existence of supervisible and superdark URLs skew the average proportion of dark retweets in a dataset. Dark retweet behaviour was explored further by examining the average reach of retweet actions and identifying content domains in which dark retweets seem more prevalent. It was found that 1) the average reach of a dark retweet action (3,614 users per retweet) was found to be just over double the average reach of a visible retweet action (1,675 users per retweet), and 2) dark retweets were more frequently used in spreading social media (41% of retweets) and spam (40.6%) URLs, whilst they were least prevalent in basic information domains such as music (8.5%), photos (5%) and videos (3.9%). It was also found that once the supervisible and superdark URLs were discarded from the analysis, the proportion of dark retweets decreased from 20.8% to 12%, whilst visible retweets increased from 79.2% to 88%. This research contributes a 19-type tweet propagation typology and the findings that dark retweets exist, but their behaviour varies depending on the retweeter and URL content domain.

Doutoramento em Engenharia Eletrotécnica
Motivado pela larga expansão dos sistemas RFID e com o desenvolvimento do conceito de Internet das Coisas, a evolução no desenho e métodos de produção de antenas em suportes de materiais alternativos tem tido uma exploração intensiva nos últimos anos. Isto permitiu, não só o desenvolvimento de produtos no campo da interação homem-máquina, mas também tornar estes produtos mais pequenos e leves. A procura de novas técnicas e métodos para produzir eletrónica impressa e antenas em materiais alternativos e, portanto, uma porta aberta para o aparecimento de novas tecnologias. Isto aplica-se especialmente no mercado dos sensores, onde o peso, o tamanho, o consumo energético, e a adaptabilidade a diversos ambientes, têm grande relevância. Esta tese foca-se no desenvolvimento de antenas com suporte em materiais não convenvionais, como os já testados papel e têxteis, mas também na exploração de outros, desconhecidos do ponto de vista eléctrico, como a cortiça e polímeros biodegradáveis usados em impressão 3D. Estes materiais são portanto usados como substrato, ou material de suporte, para diversas antenas e, como tal, as propriedades electromagnéticas destes materiais têm de ser determinadas. Assim, e apresentado neste documento uma revisão de métodos de caracterização de materiais, bem como a proposta de um método baseado em linhas de trasmissão impressas, e a respectiva caracterização electromagnética de diversos materiais. Além disso, são propostos desenhos de antenas para diversos cenários e aplicações utilizando os materiais anteriormente mencionados. Com esta tese concluiu-se que a utilização de materiais alternativos e hoje uma realidade e os resultados obtidos são muito encorajodares para o desenvolvimento de um conjunto de sensores para aplicações RFID com uma grande capacidade de integração.
The advancement of the design and fabrication of antennas using textiles or paper as substrates has rapidly grown motivated by the boom of RFID systems and the developing concept of the Internet of Things. These advancements have allowed, not only the development of products for manmachine interaction, but also to make these products smaller and lighter. The search for new techniques and methods to produce printed electronics and antennas in alternative materials is therefore an open door for new technologies to emerge. Especially in the sensors market, where weight, size, power consumption and the adaptability to the target application, are of great importance. This thesis focuses on the development of antenna design approaches with alternative materials, such as the already tested paper and textiles, but also others relatively unknown, such as cork and biodegradable polymers used in 3D printing. These materials are applied to act as substrates, or support structures for the antennas. Therefore, their electromagnetic properties need to be determined. Due to that, a review of electromagnetic characterization methods, as well as the proposal of a custom method based on printed transmission lines, is presented in this document. Besides, several antenna designs, for di erent application scenarios, using the previously mentioned materials, are proposed. With this thesis it was proved that it is possible to develop passive sensors in di erent alternative materials for RFID applications and others, which shows great promise in the use of these materials to achieve higher integration in sensing and identi cation applications.

Ce manuscrit présente une étude expérimentale de phase isolante non-conventionnelle, l'isolant d'Anderson, induit par le désordre, l'isolant de Mott, induit par les interactions de Coulomb, et les isolants topologiques.Dans une première partie du manuscrit, je décrirais le développement d'une méthode pour étudier la réponse de charge de nanoparticules par Microscopie à Force Electrostatique (EFM). Cette méthode a été appliquée à des nanoparticules de magnétite (Fe3O4), un matériau qui présente une transition métal-isolant, i.e. la transition de Verwey, lors de son refroidissement en dessous d'une température TV~120 K.Dans une seconde partie, ce manuscrit présente une étude détaillée de l'évolution de la densité d'états au travers de la transition métal-isolant entre un isolant de type Anderson-Mott et une phase métallique dans le matériau SrTiO3, et ceci, en fonction de la concentration de dopants, les lacunes d'oxygènes. Nous avons trouvé que dans un dispositif memoresistif de type Au-SrTiO3-Au, la concentration de dopants pouvait être ajustée par migration des lacunes d'oxygènes à l'aide d'un champ. Dans cette jonction tunnel, l'évolution de la densités d'états au travers de la transition métal-isolant peut être étudiée de façon continue. Finalement, dans une troisième partie, le manuscrit présente le développement d'une méthode pour la microfabrication d'anneaux de Aharonov-Bohm avec l'isolant topologique, Bi2Se3, déposée par épitaxie à jet moléculaire. Des résultats préliminaires sur les propriétés de transport quantique de ces dispositifs seront présentés
This manuscript presents an experimental study of unconventional insulating phases, which are the Anderson insulator, induced by disorder, the Mott insulator, induced by Coulomb interactions, and topological insulators.In a first part of the manuscript, I will describe the development of a method to study the charge response of nanoparticles through Electrostatic Force Microscopy (EFM). This method has been applied to magnetite Fe3O4 nanoparticles, a material that presents a metal-insulator transition, i.e. the Verwey transition, upon cooling the system below a temperature Tv=120K. In a second part, this manuscript presents a detailed study of the evolution of the Density Of States (DOS) across the metal-insulator transition between an Anderson-Mott insulator and a metallic phase in the material SrTiO3 and this, as function of dopant concentration, i.e. oxygen vacancies. We found that in this memristive type device Au-SrTiO3-Au, the dopant concentration could be fine-tuned through electric-field migration of oxygen vacancies. In this tunnel junction device, the evolution of the DOS can be followed continuously across the metal-insulator transition. Finally, in a third part, the manuscript presents the development of a method for the microfabrication of Aharonov-Bohm rings with the topological insulator material, Bi2Se3, grown by molecular beam epitaxy. Preliminary results on the quantum transport properties of these devices will be presented

This thesis investigates the design, performance and fault tolerant capability of electric machines with unconventional topologies used in more electric drive applications. Two different machine topologies are analysed: Flux reversal permanent magnet machine and a field wound flux switching machine. Initially, unconventional flux reversal machine topology in which the volume of the permanent magnet material is minimised to improve the fault tolerance capability and lower the costs whilst achieving significant improvement in the torque is investigated through a simulation and validated through experimental work. It is shown that although the machine belongs to the fault tolerant category, an inter-turn short circuit fault will be a problematic as the magnetic flux from the magnet cannot be neutralised and can cause severe damage to the machine under certain conditions. This however, does not mean that the topologies with permanent magnet material are not suitable for the fault tolerant solutions. If the appropriate design selection in terms of slot and pole numbers is made, the negative influence of the permanent magnet material can be minimised. Therefore, the influence of the slot pole combination on both fault tolerance and performance is investigated and the results are demonstrated on the set of permanent magnet synchronous machines. It is shown that low rotor pole number machines have better fault tolerance capability whilst high rotor pole number machines are lighter and provide higher efficiency. To overcome the challenges related to the short circuit fault, the topology which eliminates the permanent magnet material and works on a basis of the wound excitation is developed. As the short circuit fault cannot be fully eliminated, a solution which prevent the catastrophic failure and minimises the consequences by using wound excitation system on the stator side instead of permanent magnets is proposed. The modification of a permanent magnet synchronous machine towards improvement of the fault tolerance is presented in detail. Different rotor structures are investigated and optimised to maximise the torque performance. It is shown that using stator of existing machine and replacing the current rotor containing permanent magnets not only improves the fault tolerance, but also reduces the manufacturing and material costs.

Le problème de la détection et de ladescription des nouveaux états quantiquesmacroscopiques, caractérisées par des propriétésexotiques et non-conventionnelles, estd’importance fondamentale dans la physiquemoderne. Ces états offrent des perspectivesfascinantes dans le domaine de traitementd’information, de simulations quantiques et derecherche des nouveaux types des matériaux.Dans ce travail de thèse nous développons unethéorie qui permet de décrire des phases non conventionnellesdans des systèmes des gazultra-froids dipolaires. Ces systèmes sontactivement étudiés expérimentalement enutilisant des atomes à grand-spins, desmolécules polaires et des excitations dipolairesdans des semi-conducteurs. Nous mettonsl'accent sur la révélation du rôle de l’interactiondipôle-dipôle à long porté.Nous considérons l’effet de rotonization dansun système de gaz des bosons dipolaires «tiltés»aux interactions faibles dans une couchehomogène. Nous prédisons l’effet derotonization pour un gaz de Bose faiblementcorrélé des excitons dipolaires dans une couchede semi-conducteur et nous calculons lediagramme de stabilité. Ensuite, nousconsidérons des superfluides d’onde-p desfermions identiques dans des réseaux 2D.Finalement, nous faisons une discussion sur unautre état superfluide intéressant des moléculespolaires fermioniques, qui devrait apparaitredans des systèmes bicouches
The problem of revealing anddescribing novel macroscopic quantum statescharacter- ized by exotic and non-conventionalproperties is of fundamental importance formodern physics. Such states offer fascinatingprospects for potential applications in quantumin- formation processing, quantum simulation,and material research. In the present Thesis wedevelop a theory for describing nonconventionalphases of ultracold dipolar gases.The related systems of large-spin atoms, polarmolecules, and dipolar excitons in semiconductorsare actively studied in experiments.We put the main emphasis on revealing the roleof the long-range character of the dipole-dipoleinteraction.We consider the effect of rotonization for a 2Dweakly interacting gas of tilted dipolar bosonsin a homogeneous layer. We predict the effectof rotonization for a weakly correlated Bosegas of dipolar excitons in a semiconductorlayer and calculate the stability diagram. Wethen consider p-wave superfluids of identicalfermions in 2D lattices. Finally, we discussanother interesting novel superfluid offermionic polar molecules

The present work studies a km-scale data assimilation scheme based on a LETKF developed for the COSMO model. The aim is to evaluate the impact of the assimilation of two different types of data: temperature, humidity, pressure and wind data from conventional networks (SYNOP, TEMP, AIREP reports) and 3d reflectivity from radar volume. A 3-hourly continuous assimilation cycle has been implemented over an Italian domain, based on a 20 member ensemble, with boundary conditions provided from ECMWF ENS. Three different experiments have been run for evaluating the performance of the assimilation on one week in October 2014 during which Genova flood and Parma flood took place: a control run of the data assimilation cycle with assimilation of data from conventional networks only, a second run in which the SPPT scheme is activated into the COSMO model, a third run in which also reflectivity volumes from meteorological radar are assimilated. Objective evaluation of the experiments has been carried out both on case studies and on the entire week: check of the analysis increments, computing the Desroziers statistics for SYNOP, TEMP, AIREP and RADAR, over the Italian domain, verification of the analyses against data not assimilated (temperature at the lowest model level objectively verified against SYNOP data), and objective verification of the deterministic forecasts initialised with the KENDA analyses for each of the three experiments.

This thesis focuses on the assembly of non-conventional templated polyoxotungstates, specifically on the 6A group anions such as SO32-, SeO32- and TeO66-, which results in the discovery of 40 new polyoxotungstate compounds from the traditional Dawson-like cluster {SW18} to the nanoscale cluster {Se8W119} cluster. This study demonstrated that the identification and isolation of discrete building blocks to produce versatile and modular species can be assembled in a controlled manner, and it still represents a fundamental objective in the development of inorganic chemistry from the molecule to the nano world. The assembly of Iso-polyoxotungstate fragments can be affected by a few key reaction variables including, but not limited to, pH, temperature, ionic strength, type of cations and solvents. Carefully screening and controlling the reaction conditions can result in the isolation of the different aggregate behaviour of building blocks such as {W11} units. Further, the use of synthetically innocent anions appears to be important in the assembly of Iso-polyoxtungstate with pentagonal units. The Dawson-Like type X ⊂ {W18O54} (X= SIV, SeIV or TeVI) clusters can be reasonably designed and were isolated in a “one-pot” procedure by using a “shrink wrapping” strategy. These clusters are fully characterized by XRD, ESI-MS/CSI-MS and chemical analysis, IR, as well as by preliminary electrochemical studies. The effects of organo-cation, ionic strength and pH are investigated, especially in tungstoselenite and tungstotellurate chemistry. The synthetic methodology is also developed, the combination of building block strategy and solvent & cation exchange methods lead to the isolation of a series of new polyoxotungstate compounds including an “in-situ” reduction product {TeIVW18}, the thermochromic {Se2W18} cluster, and the organic soluble lacunary cluster {Se2W19}. These discoveries lead to a general new polyoxometalate building block approach and start a new field in polyoxotungstate synthesis.

Emerging techniques of intelligent or learning control seem attractive for applications in manufacturing and robotics. It is however important to understand the capabilities of such control systems. In the past the inverted pendulum has been used as a test case. The thesis begins with an examination of whether the inverted pendulum or polecart balancing problem is a representative problem for experimentation for learning controllers for complex nonlinear systems. Results of previous research concerning the inverted pendulum problem are presented to show that this problem is not sufficiently testing. This thesis therefore concentrates on the control of the inverted pendulum with an additional degree of freedom as a testing demonstrator problem for learning control system experimentation. A flexible pole is used in place of a rigid one. The transverse displacement of the flexible pole adds a degree of freedom to the system. The dynamics of this new system are more complex as the system needs additional parameters to be defIned due to the pole's elastic deflection. This problem also has many of the signifIcant features associated with flexible robots with lightweight links as applied in manufacturing. Novel neural network and fuzzy control systems are presented that control such a system both in simulation and real time. A fuzzy-genetic approach is also demonstrated that allows the creation of fuzzy control systems without the use of extensive knowledge.

The way the temperature is distributed inside the material is of prime importance in laser materials processing. Optimisation of different laser processes requires control over the temperature distribution in order to control microstructure and residual stressesb y manipulating heating/cooling rates and thermal gradients. Currently most of the laser material processing is carried out by either circular or rectangular beam geometry with variation in temperature distribution caused by either the variation of laser power, spot size or scanning speed. Variations in these parameters are often limited by other processing conditions, therefore the possibility of modifying the microstructure and residual stresses are limited. If any other parameter can be identified, such that variation of this parameter alone (i. e. without changing the laser power or scanning speed) can alter the temperature distribution, then it will provide added flexibility to the process control. One possible method of varying the temperature distribution, and hence the heating /cooling rates and thermal gradients is to modify the geometry of laser beams. The effect of laser beam geometry, particularly of non-conventional laser beam geometries on laser processing of materials has received very little attention. This thesis presents a detailed numerical investigation of the effects of non-conventional laser beam geometries on laser surface heating, laser transformation hardening, laser tube bending and laser melting of metallic materials. The numerical models have been validated by experiments using a diode laser. The temperature distributions, heating/cooling rates, thermal gradients, stress distributions and distortions were evaluated. The work presented in this thesis highlights the different attributes of conventional and non-conventional laser beam geometries. Laser beam geometries were found to influence heating and cooling rates as well as residual and normal stress distributions in materials processing. In particular, the donut beam results in transient bi-axial stress state which does not exist for any other solid beam geometry. These attributes can be utilised as an advantage not only in the investigated processes but could also be utilised for improving various other laser material processes

Dissertação (mestrado)—Universidade de Brasília, Faculdade de Tecnologia, Departamento de Engenharia Elétrica, 2016.
Conforme o sangue flui através do corpo de um indivíduo, ele muda a forma como a luz é irradiada pela pele, pois o sangue absorve luz de forma diferente dos outros tecidos. Essa sutil variação pode ser capturada por uma câmera e ser usada para monitorar a atividade cardíaca de uma pessoa. O sinal capturado pela câmera é uma onda que representa as variações de tonalidade da pele ao longo do tempo. A frequência dessa onda é a mesma frequência na qual o coração bate. Portanto, o sinal capturado pela câmera pode ser usado para estimar a taxa cardíaca de uma pessoa. Medir o pulso cardíaco remotamente traz mais conforto pois evita o uso de eletrodos. Também permite o monitoramento de uma pessoa de forma oculta para ser empregado em um detector de mentira, por exemplo. Neste trabalho nós propomos dois algoritmos para a estimação da taxa cardíaca sem contato usando câmeras convencionais sob iluminação não controlada. O primeiro algoritmo proposto é um método simples que emprega um detector de face que identifica a face da pessoa sendo monitorada e extrai o sinal gerado pelas mudanças no tom da pele devido ao fluxo sanguíneo. Este algoritmo emprega um filtro adaptativo para aumentar a energia do sinal de interesse em relação ao ruído. Nós mostramos que este algoritmo funciona muito bem para vídeos com pouco movimento. O segundo algoritmo que propomos é uma melhora do primeiro para torná-lo mais robusto a movimentos. Nós modificamos o método usado para definir a região de interesse. Neste algoritmo é utilizado um detector de pele para eliminar pixels do plano de fundo do vídeo, os frames dos vídeos são divididos em micro-regiões que são rastreados com um algoritmo de fluxo ótico para compensar os movimentos e um algoritmo de clusterização é aplicado para selecionar automaticamente as melhores micro-regiões para efetuar a estimação da taxa cardíaca. Propomos também um esquema de filtragem temporal e espacial para reduzir o ruído introduzido pelo algoritmo de fluxo ótico. Comparamos os resultados dos nossos algoritmos com um oxímetro de dedo comercial e mostramos que eles funcionam bem para situações desafiadoras.
As the blood flows through the body of an individual, it changes the way that light is irradiated by the skin, because blood absorbs light differently than the remaining tissues. This subtle variation can be captured by a camera and be used to monitor the heart activity of a person. The signal captured by the camera is a wave that represents the changes in skin tone along time. The frequency of this wave is the same as the frequency by which the heart beats. Therefore, the signal captured by the camera could be used to estimate a person’s heart rate. This remote measurement of cardiac pulse provides more comfort as it avoids the use of electrodes or others devices attached to the body. It also allows the monitoring of a person in a canceled way to be employed in lie detectors, for example. In this work we propose two algorithms for non-contact heart rate estimation using conventional cameras under uncontrolled illumination. The first proposed algorithm is a simple approach that uses a face detector to identify the face of the person being monitored and extract the signal generated by the changes in the skin tone due to the blood flow. This algorithm employs an adaptive filter to boost the energy of the interest signal against noise. We show that this algorithm works very well for videos with little movement. The second algorithm we propose is an improvement of the first one to make it more robust to movements. We modify the approach used to define the region of interest. In this algorithm we employ a skin detector to eliminate pixels from the background, divide the frames in microregions that are tracked using an optical flow algorithm to compensate for movements and we apply a clustering algorithm to automatically select the best micro-regions to use for heart rate estimation. We also propose a temporal and spatial filtering scheme to reduce noise introduced by the optical flow algorithm. We compared the results of our algorithms to an off-the-shelf fingertip pulse oximeter and showed that they can work well under challenging situations.

Ces dernières années, la biométrie a fait l’objet d’une grande attention en raison du besoin sans cesse croissant d’authentification d’identité, notamment pour sécuriser de plus en plus d’applications enlignes. Parmi divers traits biométriques, le visage offre des avantages compétitifs sur les autres, e.g., les empreintes digitales ou l’iris, car il est naturel, non-intrusif et facilement acceptable par les humains. Aujourd’hui, les techniques conventionnelles de reconnaissance faciale ont atteint une performance quasi-parfaite dans un environnement fortement contraint où la pose, l’éclairage, l’expression faciale et d’autres sources de variation sont sévèrement contrôlées. Cependant, ces approches sont souvent confinées aux domaines d’application limités parce que les environnements d’imagerie non-idéaux sont très fréquents dans les cas pratiques. Pour relever ces défis d’une manière adaptative, cette thèse porte sur le problème de reconnaissance faciale non contrôlée, dans lequel les images faciales présentent plus de variabilités sur les éclairages. Par ailleurs, une autre question essentielle vise à profiter des informations limitées de 3D pour collaborer avec les techniques basées sur 2D dans un système de reconnaissance faciale hétérogène. Pour traiter les diverses conditions d’éclairage, nous construisons explicitement un modèle de réflectance en caractérisant l’interaction entre la surface de la peau, les sources d’éclairage et le capteur de la caméra pour élaborer une explication de la couleur du visage. A partir de ce modèle basé sur la physique, une représentation robuste aux variations d’éclairage, à savoir Chromaticity Invariant Image (CII), est proposée pour la reconstruction des images faciales couleurs réalistes et sans ombre. De plus, ce processus de la suppression de l’ombre en niveaux de couleur peut être combiné avec les techniques existantes sur la normalisation d’éclairage en niveaux de gris pour améliorer davantage la performance de reconnaissance faciale. Les résultats expérimentaux sur les bases de données de test standard, CMU-PIE et FRGC Ver2.0, démontrent la capacité de généralisation et la robustesse de notre approche contre les variations d’éclairage. En outre, nous étudions l’usage efficace et créatif des données 3D pour la reconnaissance faciale hétérogène. Dans un tel scénario asymétrique, un enrôlement combiné est réalisé en 2D et 3D alors que les images de requête pour la reconnaissance sont toujours les images faciales en 2D. A cette fin, deux Réseaux de Neurones Convolutifs (Convolutional Neural Networks, CNN) sont construits. Le premier CNN est formé pour extraire les descripteurs discriminants d’images 2D/3D pour un appariement hétérogène. Le deuxième CNN combine une structure codeur-décodeur, à savoir U-Net, et Conditional Generative Adversarial Network (CGAN), pour reconstruire l’image faciale en profondeur à partir de son homologue dans l’espace 2D. Plus particulièrement, les images reconstruites en profondeur peuvent être également transmise au premier CNN pour la reconnaissance faciale en 3D, apportant un schéma de fusion qui est bénéfique pour la performance en reconnaissance. Notre approche a été évaluée sur la base de données 2D/3D de FRGC. Les expérimentations ont démontré que notre approche permet d’obtenir des résultats comparables à ceux de l’état de l’art et qu’une amélioration significative a pu être obtenue à l’aide du schéma de fusion
In recent years, biometrics have received substantial attention due to the evergrowing need for automatic individual authentication. Among various physiological biometric traits, face offers unmatched advantages over the others, such as fingerprints and iris, because it is natural, non-intrusive and easily understandable by humans. Nowadays conventional face recognition techniques have attained quasi-perfect performance in a highly constrained environment wherein poses, illuminations, expressions and other sources of variations are strictly controlled. However these approaches are always confined to restricted application fields because non-ideal imaging environments are frequently encountered in practical cases. To adaptively address these challenges, this dissertation focuses on this unconstrained face recognition problem, where face images exhibit more variability in illumination. Moreover, another major question is how to leverage limited 3D shape information to jointly work with 2D based techniques in a heterogeneous face recognition system. To deal with the problem of varying illuminations, we explicitly build the underlying reflectance model which characterizes interactions between skin surface, lighting source and camera sensor, and elaborate the formation of face color. With this physics-based image formation model involved, an illumination-robust representation, namely Chromaticity Invariant Image (CII), is proposed which can subsequently help reconstruct shadow-free and photo-realistic color face images. Due to the fact that this shadow removal process is achieved in color space, this approach could thus be combined with existing gray-scale level lighting normalization techniques to further improve face recognition performance. The experimental results on two benchmark databases, CMU-PIE and FRGC Ver2.0, demonstrate the generalization ability and robustness of our approach to lighting variations. We further explore the effective and creative use of 3D data in heterogeneous face recognition. In such a scenario, 3D face is merely available in the gallery set and not in the probe set, which one would encounter in real-world applications. Two Convolutional Neural Networks (CNN) are constructed for this purpose. The first CNN is trained to extract discriminative features of 2D/3D face images for direct heterogeneous comparison, while the second CNN combines an encoder-decoder structure, namely U-Net, and Conditional Generative Adversarial Network (CGAN) to reconstruct depth face image from its counterpart in 2D. Specifically, the recovered depth face images can be fed to the first CNN as well for 3D face recognition, leading to a fusion scheme which achieves gains in recognition performance. We have evaluated our approach extensively on the challenging FRGC 2D/3D benchmark database. The proposed method compares favorably to the state-of-the-art and show significant improvement with the fusion scheme

Metamaterials are artificial media composed of subwavelength unit cells, specifically engineered to exhibit unusual properties in relation to wave propagation, generally not found in nature. Most research in this area has been dedicated to electromagnetic metamaterials, In this thesis we present results in a new multidisciplinary field of metamaterials in acoustics and realization of non-conventional wave propagation applying novel metamaterial unit cells. The scientific contribution of this dissertation comprises three new types of wave propagation modes and their control with newly designed metamaterial unit cells. In the thesis, a novel class of compressibility-near-zero (CNZ) acoustic propagation, achieved by using Helmholtz resonators, is theoretically analyzed and experimentally demonstrated. A closed analytical formula for the effective compressibility of the proposed unit cell is presented, and the existence of two frequencies which may support CNZ propagation is shown. Furthermore, a new unit cell with effective mass density with Lorentzian type behavior is proposed, a closed analytical formula for its effective mass density is found, and the evanescent, left-handed propagation and density-near-zero acoustic wave propagation are demonstrated. In the end it is demonstrated for the first time that a surface acoustic wave propagating at the boundary between a fluid and a hard grooved surface can be efficiently controlled by varying only the temperature of the fluid, while the geometry of the grooved surface remains unchanged. This opens up a way for a number of new applications, all easily tunable by external means. Following theoretical considerations, we demonstrate temperature-controlled sound trapping and its applications in acoustic spectral analysis and temperature sensing. We also present a temperature-controlled gradient refractive index (GRIN) acoustic medium and apply it to achieve temperature-controlled acoustic focusing.
Метаматеријали су вештачки медијуми састављени од јединичних ћелија мањих од таласне дужине, пројектовани на посебан начин да при пропагацији таласа испољавају необичне особине које се иначе не срећу у природи. Већина истраживања у овој области фокусира се на електромагнетске метаматеријале. У овој дисертацији презентовани су резултати у новом мултидисциплинарном пољу метаматеријала у акустици и реализација нове неконвенционалне пропагације таласа применом јединичних ћелија метаматеријала. Научни допринос ове дисертације су три нова типа модова пропагације таласа и њихова контрола новим пројектованим јединичним ћелијама метаматеријала. У дисертацији је теоријски анализирана и експериментално показана нова класа CNZ (енг. compressibility-near-zero) акустичке пропагације постигнуте Хелмхолцовим резонатором. Дата је затворена аналитичка формула за ефективну стишљивост јединичне ћелије, а затим је показано да постоје две фреквенције које подржавају CNZ пропагацију. Такође, предложена је нова јединична ћелија са ефективном густином Лоренцовог типа, изведена је затворена аналитичка формула за њену ефективну густину и показане су „левoрука“, еванесцентна и DNZ (енг. density-near-zero) пропагација акустичких таласа. На крају, по први пут је показано да се површински акустични талас који се простире на граници између флуида и чврсте избраздане површи може ефикасно контро-лисати само променом температуре, док геометрија избраздане површи остаје непромењена. Ово отвара могућности за бројне нове примене где је потребна лакоћа екстерног подешавања. Пратећи изложену теорију, демонстрирано је заробљавање звука контролисано температуром, као и његова примена у акустичкој спектралној анализи и мерењу темпе-ратуре. Такође, презентован је акустички медијум са температуром кон-тролисаним градијентом индекса преламања, као и његова примену у температурно контролисаном акустичком фокусирању.
Metamaterijali su veštački medijumi sastavljeni od jediničnih ćelija manjih od talasne dužine, projektovani na poseban način da pri propagaciji talasa ispoljavaju neobične osobine koje se inače ne sreću u prirodi. Većina istraživanja u ovoj oblasti fokusira se na elektromagnetske metamaterijale. U ovoj disertaciji prezentovani su rezultati u novom multidisciplinarnom polju metamaterijala u akustici i realizacija nove nekonvencionalne propagacije talasa primenom jediničnih ćelija metamaterijala. Naučni doprinos ove disertacije su tri nova tipa modova propagacije talasa i njihova kontrola novim projektovanim jediničnim ćelijama metamaterijala. U disertaciji je teorijski analizirana i eksperimentalno pokazana nova klasa CNZ (eng. compressibility-near-zero) akustičke propagacije postignute Helmholcovim rezonatorom. Data je zatvorena analitička formula za efektivnu stišljivost jedinične ćelije, a zatim je pokazano da postoje dve frekvencije koje podržavaju CNZ propagaciju. Takođe, predložena je nova jedinična ćelija sa efektivnom gustinom Lorencovog tipa, izvedena je zatvorena analitička formula za njenu efektivnu gustinu i pokazane su „levoruka“, evanescentna i DNZ (eng. density-near-zero) propagacija akustičkih talasa. Na kraju, po prvi put je pokazano da se površinski akustični talas koji se prostire na granici između fluida i čvrste izbrazdane površi može efikasno kontro-lisati samo promenom temperature, dok geometrija izbrazdane površi ostaje nepromenjena. Ovo otvara mogućnosti za brojne nove primene gde je potrebna lakoća eksternog podešavanja. Prateći izloženu teoriju, demonstrirano je zarobljavanje zvuka kontrolisano temperaturom, kao i njegova primena u akustičkoj spektralnoj analizi i merenju tempe-rature. Takođe, prezentovan je akustički medijum sa temperaturom kon-trolisanim gradijentom indeksa prelamanja, kao i njegova primenu u temperaturno kontrolisanom akustičkom fokusiranju.

In Chapter 1 I will present a brief introduction on the state of art of nanotechnologies, nanofabrication techniques and unconventional lithography as a technique to fabricate the novel electronic device as resistive switch so-called memristor is shown. In Chapter 2 a detailed description of the main fabrication and characterization techniques employed in this work is reported. Chapter 3 parallel local oxidation lithography (pLOx) describes as a main technique to obtain accurate patterning process. All the effective parameters has been studied and the optimized condition observed to highly reproducible with excellent patterned nanostructures. The effect of negative bias, calls local reduction (LR) studied. Moreover, the use of AC bias shows faster patterning process respect to DC bias. In Chapter 4 (metal/ e-SiO2/ Si nanojunction) it is shown how the electrochemical oxide nanostructures by using pLOx can be used in the fabrication of novel devices call memristor. We demonstrate a new concept, based on conventional materials, where the lifetime problem is resolved by introducing a “regeneration” step, which restores the nano-memristor to its pristine condition by applying an appropriate voltage cycle. In Chapter 5 (Graphene/ e-SiO2/ Si), Graphene as a building block material is used as an electrode to selectively oxidize the silicon substrate by pLOx set up for the fabrication of novel resistive switch device. In Chapter 6 (surface architecture) I will show another application of pLOx in biotechnology is shown. So the surface functionalization combine with nano-patterning by pLOx used to design a new surface to accurately bind biomolecules with the possibility of studying those properties and more application in nano-bio device fabrication. So, in order to obtain biochips, electronic and optical/photonics devices Nano patterning of DNA used as scaffolds to fabricate small functional nano-components.

In Chapter 1 I will present a brief introduction on the state of art of nanotechnologies, nanofabrication techniques and unconventional lithography as a technique to fabricate the novel electronic device as resistive switch so-called memristor is shown. In Chapter 2 a detailed description of the main fabrication and characterization techniques employed in this work is reported. Chapter 3 parallel local oxidation lithography (pLOx) describes as a main technique to obtain accurate patterning process. All the effective parameters has been studied and the optimized condition observed to highly reproducible with excellent patterned nanostructures. The effect of negative bias, calls local reduction (LR) studied. Moreover, the use of AC bias shows faster patterning process respect to DC bias. In Chapter 4 (metal/ e-SiO2/ Si nanojunction) it is shown how the electrochemical oxide nanostructures by using pLOx can be used in the fabrication of novel devices call memristor. We demonstrate a new concept, based on conventional materials, where the lifetime problem is resolved by introducing a “regeneration” step, which restores the nano-memristor to its pristine condition by applying an appropriate voltage cycle. In Chapter 5 (Graphene/ e-SiO2/ Si), Graphene as a building block material is used as an electrode to selectively oxidize the silicon substrate by pLOx set up for the fabrication of novel resistive switch device. In Chapter 6 (surface architecture) I will show another application of pLOx in biotechnology is shown. So the surface functionalization combine with nano-patterning by pLOx used to design a new surface to accurately bind biomolecules with the possibility of studying those properties and more application in nano-bio device fabrication. So, in order to obtain biochips, electronic and optical/photonics devices Nano patterning of DNA used as scaffolds to fabricate small functional nano-components.

6.1 INTRODUCCIÓ Des del 2001, el grup de Química Organometàl¿lica i Catàlisis Homogènia de la Universitat Jaume I, QOMCAT, dirigit pel professor Eduardo Peris, ha centrat els seus esforços en la investigació i desenvolupament de nous lligands de tipus carbè N-heterocíclics (NHCs) per a la preparació de catalitzadors metàl¿lics millorats. La versatilitat dels lligands de tipus NHC, a més de la fàcil preparació dels seus precursors (normalment sals d'azoli), han permès dissenyar una gran varietat de topologies i formes de coordinació. Dins d'aquest context, aquest grup va iniciar algunes línies d'investigació relacionades amb la 'Química Verda'. Així, nous complexos que contenien lligands NHC van ser sintetitzats per a la reducció de CO2 utilitzant iPrOH en lloc de H2, fent el procés més segur i respectuós amb el medi ambient. A més, la funcionalització de lligands NHC amb grups polars va permetre la síntesi de catalitzadors solubles en dissolvents sostenibles (aigua i glicerol),1-6 i també l'ús d'altres eines d'activació de calefacció d'energia alternativa (MW or US).4-5 Més recentment, el grup va reorientar els seus esforços en el disseny d'estructures rígides basades en lligands poli-NHC per a la preparació de catalitzadors homo- i heterometàl¿lics.7-10 Aquest tipus de policarbens poden estar units mitjançant sistemes rígids ¿-conjugats i poden ser capaços de comunicar electrònicament les unitats carbèniques. Aquesta característica dels complexos poli-NHC pot tindre molt d'interès per a la fabricació de dispositius electrònics moleculars a més de les importants millores catalítiques que pot implementar. A continuació s'inclou una breu ressenya sobre els avanços fets durant aquesta tesi doctoral: Disseny de catalitzadors per al desenvolupament de processos verds i síntesi de nous complexos basats en lligands imidazolilidè-piridilidè i poli-NHC. Els processos verds que decidírem estudiar són la reacció Suzuki-Miyaura d'acoblament C-C en aigua i l'alquilació d'amoníac amb alcohols primaris que transcorre a través d'un mecanisme de "préstec d'hidrogen", conegut més habitualment pel terme anglès Borrowing-Hydrogen. Les reaccions d'acoblament C-C catalitzades per metalls de transició són un dels mètodes més utilitzats per a la formació d'enllaços C-C, sent el pal¿ladi el metall més utilitzat per a desenvolupar aquest tipus de reaccions. Entre aquests processos, la reacció d'acoblament Suzuki-Miyaura, és a dir, l'acoblament entre un àcid arilborònic i un halur d'aril,11 és el protocol més utilitzat per a sintetitzar bifenils atesa la bona tolerància davant diferents grups funcionals. Per aquesta raò, trobar una alternativa més respectuosa amb el medi ambient per a dur a terme aquesta reacció és un repte per als investigadors en el camp de la catàlisi homogènia. Els processos catalítics que s'engloben sota el terme "Borrowing-Hydrogen" constitueixen un ampli ventall de reaccions en les que el nexe comú és determinat per la intermediació d'un catalitzador que serveix com a transportador d'hidrogen entre un parell de substrats.12-15 En una reacció típica de Borrowing-Hydrogen es produeix l'oxidació d'un substrat, normalment un alcohol (o una amina), per un catalitzador metàl¿lic que 'agafa com a préstec' dos àtoms d'hidrogen. Depenent si l'alcohol és primari o secundari, es generarà un aldehid o una cetona, respectivament. Aquests compostos de carbonil poden sofrir una àmplia gama de transformacions ja que poden reaccionar in situ per a donar imines, alquens i compostos de carbonil funcionalitzats. El catalitzador metàl¿lic, que havia agafat com a préstec l'hidrogen, el "torna" al nou compost, produint la seua reducció. Aquests processos catalítics compleixen el principi d'economia atòmica ja que, normalment, tots els àtoms dels substrats apareixen en els productes o, com a màxim, l'únic subproducte obtingut és H2O o NH3, per la qual cosa es consideren processos que contribueixen a la química verda. Els lligands de tipus imidazolilidè-piridilidè (C,C¿-imz-pyr) se formen com a conseqüència de la unió d'una unitat d'imidazolilidè i una unitat piridilidè. El primers complexos que presentaven aquest tipus de lligands (C,C¿-imz-pyr) foren descrits per Colbran,16 6.1 en Esquema 6.1. En els últims anys els lligands de tipus poli-NHC han donant lloc a una gran varietat de complexos polimetàl¿lics, amb diferents topologies que condueixen a l'obtenció de propietats catalítiques inusuals17-20 En aquest sentit, el nostre grup d'investigació ha descrit recentment lligands di- i tri-NHC amb sistemes ¿-electrònics conjuminats per a la preparació de compostos polimetàl¿lics millorats.8, 21 En particular, el lligand tri-NHC 6.2 (Esquema 6.2) va donar lloc a compostos que augmentaven la seua capacitat catalítica en comparació amb altres compostos mono metàl¿lics o tri metàl¿lics amb les mateixes característiques esteroelectròniques Hahn i col¿laboradors van ser els primers a descriure una estructura supramolecular metàl¿lica tridimensional que contenia exclusivament enllaços metall-NHC (6.3, Esquema 6.3).22 Aquesta estructura es va sintetitzar per reacció directa de dos lligands hexa-NHC amb Ag2O. En principi, aquest tipus d'estructures poden ser utilitzades com a caixes macromoleculars encercladores de molècules menudes neutres o iòniques i, per tant, funcionar com a detectors químics.23-28 En concret en el compost 6.3 es mostra la presència d¿un ió bromur a l¿interior de la caixa. 6.2 OBJECTIUS L'objectiu general d'aquesta tesi doctoral és la síntesi de catalitzadors homogenis amb propietats esteroelectròniques millorades. En aquest sentit, el treball es centra en la preparació i caracterització de nous complexos metàl¿lics amb diferents lligands de tipus carbè N-heterocíclic (NHC) o lligands anàlegs, l'estudi dels seus patrons de reactivitat i l'exploració de les seues propietats catalítiques. Els objectius concrets que se¿n deriven son els següents: ¿ Síntesi de complexos de pal¿ladi i iridi per al desenvolupament de processos verds. Principalment, s'intentaran realitzar reaccions catalítiques amb les condicions més respectuoses amb el medi ambient, utilitzant dissolvents no tòxics, amb la màxima economia atòmica i sense malbaratament d'energia. ¿ Estudi sistemàtic de la reactivat de lligands imidazolilidè-piridilidè mitjançant la seua coordinació a precursors de rodi i iridi. ¿ Disseny, síntesi i coordinació de lligands poli-NHC per a la preparació de complexos polimetàl¿lics amb estructures inusuals i altament simètriques. Estudi de les seues propietats electròniques. ¿ 6.3 DISCUSSIÓ DE RESULTATS 6.3.1 Síntesi de compostos de Pd(II) hidrofílics amb lligands NHC. Aplicacions catalítiques 6.3.1.1 Síntesi de compostos de Pd(II) hidrofílics amb lligands NHC L'Esquema 6.4, mostra els tres precursors dels lligands NHC, funcionalitzats amb cadenes sulfonatades, que han sigut utilitzats. El compost AH,3 ha sigut prèviament descrit en la bibliografia, mentre que, els compostos BH2 i CH2 s'han sintetitzat i caracteritzat per primera vegada al llarg del treball d'investigació que es presenta. A partir d'aquests lligands s¿han obtingut complexos de Pd(II) en els quals els lligands s'uneixen al metall de forma mono coordinada, quelat i pinça. Hem tractat que l'elecció d'aquest tipus de modes de coordinació donen lloc a un ampli conjunt de topologies de complexos de pal¿ladi NHC que ja han demostrat propietats catalítiques eficients en dissolvents orgànics.29-30 L'estratègia de metal¿lació utilitzada ha sigut l'ús d'una base dèbil incorporada en el precursor de pal¿ladi per a desprotonar els compostos d'imidazolilidè segons es mostra en l'Esquema 6.5. Els compostos d'imidazoli BH2 i CH2 junt amb els catalitzadors 1A-4C descrits en aquesta secció, han sigut sintetitzats per primera vegada al llarg del treball d'investigació que es presenta i han sigut caracteritzats per espectroscòpia d'RMN, espectrometria de masses i per anàlisi elemental. El complex 4C va ser sintetitzat, ja que la introducció d'un lligand piridina ha demostrat millorar l'activitat catalítica dels compostos amb els quals es coordina per efecte "PEPPSI".31-33 6.3.1.2 Aplicacions catalítiques Amb la finalitat d'avaluar les propietats catalítiques dels complexos hidrofílics preparats en l'apartat anterior, decidírem utilitzar-los en la reacció d'acoblament C-C de Suzuki-Miyaura en aigua, on un àcid arilborònic reacciona amb un halur d'aril per a donar un compost biarilat. Així, es va fer reaccionar l'àcid fenilborònic amb vuit halurs d'aril diferents (4-brom, i 4-cloracetofenona; 4-brom, i 4-clorbenzè; 4-brom, i 4-clortoluè; 4-brom, i 4-cloranisol), tal com es mostra en l'Esquema 6.6. Les reaccions es van fer en una mescla d'aigua/iPrOH (1:1) a 110ºC, amb 1 mol% de catalitzador i en presència de K2CO3. Els resultats obtinguts ens van permetre concloure que els compostos 1A i 3C són els més actius, ja que faciliten rendiments molt elevats en temps de reacció curts (4h, per als bromur d'aril i 12h, per als clorur d'aril). Però és el catalitzador 1A amb què obtenim els resultats més espectaculars quan utilitzem 4-bromacetofenona i 4-cloracetofenona, ja que obtenim rendiments superiors al 99% en 4h i 12h, respectivament. Els resultats catalítics obtinguts suggereixen que la presència del lligand piridina en el compost 4C no augmenta l'activitat catalítica d'aquest per efecte "PEPPSI" en comparació al catalitzador 3C. 6.3.2 Síntesi de compostos de Ir(III) amb lligands formamidina. Aplicacions catalítiques 6.3.2.1 Síntesi de compostos de Ir(III) amb lligands formamidina El lligand 1,3-bis(2,4,6-trimetilfenil)formamidina, D, va ser sintetitzat seguint el procediment descrit en la literatura34 i a partir d'aquest vam obtenir dos compostos diferents de 'IrCp*' depenent de la forma de coordinar-se d'aquest. Si el lligand D adopta coordinació monodentada s'obté el compost 5D, però si la coordinació es en forma quelat obtenim el compost 6D (Esquema 6.7). Aquests dos nous compostos, 5D i 6D, han sigut caracteritzats per espectroscòpia d'RMN, espectrometria de masses i per anàlisi elemental. Les estructures moleculars dels dos compostos han sigut confirmades mitjançant Difracció de Raigs X (DRX) sobre monocristall. 6.3.2.2 Aplicacions catalítiques En aquest cas, decidírem comprovar l'activitat catalítica dels compostos 5D i 6D en dues reaccions governades per processos de Borrowing-Hydrogen. En primer lloc començàrem amb la reacció de ß-alquilació d'alcohols secundaris amb alcohols primaris per a després estendre l'estudi de l'activitat catalítica dels dos complexos en una reacció més interessant, com és l'alquilació d'amoníac amb alcohols primaris. a) ß-Alquilació d'alcohols secundaris amb alcohols primaris Aquesta reacció es va dur a terme en condicions de màxima economia atòmica, és a dir, intentant que tots els materials utilitzats com a reactius s'incorporen als productes. Així, tal com es mostra en l'Esquema 6.8, es va fer reaccionar una mescla equimolecular de l'alcohol primari, alcohol secundari i una base (KOH), en presència de 0.1-1 mol% de catalitzador en toluè a 100ºC. La reacció pot donar lloc a dos productes, l'alcohol alquilat i/o la cetona alquilada. La reacció es va dur a terme utilitzant 2-feniletanol com a alcohol secundari i quatre alcohols primaris diferents (bencilalcohol, butanol, 3-clorbencilalcohol i 4-clorbencilalcohol), utilitzant els catalitzadors 5D i 6D. Els resultats obtinguts van permetre concloure que 5D és molt més eficient que 6D, tant en termes de conversió cap als productes finals com en selectivitat cap a l'alcohol ß-alquilat. El catalitzador 5D també és molt actiu fins i tot a concentracions de 0.1 mol%, sobretot quan utilitzem bencilalcohol i 4-clorbencilalcohol. Els resultats catalítics obtinguts suggereixen que el grup NH en el lligand formamidina del complex 5D aporta un 'efecte NH'35-36 cooperatiu fent que aquest compost siga més actiu que 6D. b) Alquilació d'amoníac amb alcohols primaris En primer lloc vam comparar l'activitat catalítica de [IrCp*Cl2]2, el catalitzador d'Shvo i els nous compostos 5D i 6D. Com es mostra en l'Esquema 6.9, per a dur a terme la reacció es va fer reaccionar diferents sals d'amoni amb bencilalcohol a 110 o 130ºC, utilitzat diverses carregues de catalitzador, en presència d'un 3 mol% de NaHCO3 i amb proporcions de bencilalcohol/sal d'amoni de 3:1 o 3.6:1. El complex 5D i el catalitzador d'Shvo mostraren excel¿lents resultats catalítics en l'alquilació de la sal d'amoni NH4OAc per a obtindre trifenilamina, en comparació amb els resultats obtinguts amb [IrCp*Cl2]2 i el complex 6D sota les mateixes condicions de reacció. A més, 5D va ser moderadament actiu en l'alquilació del NH4OH. Tenint en compte les dades anteriors, decidírem ampliar l'abast del catalitzador d'Shvo i el complex 5D, estudiant la seva activitat catalítica davant una varietat d'alcohols primaris. Tal i com es mostra en l'Esquema 6.10, l'alquilació de sals d'amoni amb diferents alcohols primaris es va dur a terme a 130 o140ºC, utilitzant carregues de catalitzador d'1, 3 i 5 mol%, en presència de KOH o sense base i amb proporcions d'alcohol primari/sal d'amoni de 3.6:1 o 6:1. En aquest cas la reacció pot donar lloc a diferents amines, segons l'alcohol primari utilitzat (4-clorbencilalcohol, 3-clorbencilalcohol, 4-metilbencilalcohol, 1-hexanol, 1-butanol i 1-ciclohexanol). Els resultats obtinguts ens van permetre concloure que amb el catalitzador 5D s'obtenen resultats catalítics extraordinaris, sobretot quan utilitzem bencilalcohol, però, la seua eficiència baixa quan utilitzem alcohols alquílics. La activitat del catalitzador d'Shvo és en la majoria del casos més elevada, mostrant així la gran aplicabilitat d'aquest catalitzador exepcional. A la vista dels resultats obtinguts en les dues reaccions governades per processos de Borrowing-Hydrogen, i tal com havíem comentat anteriorment, creiem que la presència del grup NH en el lligand formamidina del complex 5D està incrementant l'activitat catalítica d'aquest davant el complex 6D i [IrCp*Cl2]2. Aquet 'efecte NH' pot estar facilitant la deshidrogenació de l'alcohol primari per a passar a aldehid en el primer pas del cicle catalític,37 d'una manera similar a les observacions descrites per Noyori en les reaccions d'hidrogenació de cetones.35-36 6.3.3 Síntesi de compostos de Rh(III) i Ir(III) basats en lligands imidazolilidè-piridilidè i estudi de la seua reactivitat no convencional Durant aquesta tesi doctoral també ens vam interessar en la síntesi de compostos de rodi i iridi amb lligands imidazolilidè-piridilidè (C,C¿-imz-pyr) coordinats en forma quelat. A més d'obtenir els compostos di-NHC esperats, també es varen sintetitzar una sèrie de compostos amb els lligands reordenats en formes poc convencionals. L'estudi d'aquests nous compostos amb lligands C,C¿-imz-pyr ofereix una bona oportunitat per a comparar les diferències estructurals i de reactivitat d'aquests complexos depenent del tipus de la coordinació del carbè (normal, abnormal o remota), tant del imidazolilidè com del piridilidè. L'Esquema 6.11 mostra les diferents sals precursores dels lligands C,C¿-imz-pyr que han sigut utilitzades. Totes aquestes sals s'han sintetitzat i caracteritzat, per primera vegada, al llarg del treball d'investigació que es presenta. 6.3.3.1 Síntesi i caracterització dels complexos [MI2(C,C'-imz-pyr)(CH3CN)2]+ (M = Rh, Ir) En primer lloc, vam obtenir una sèrie de complexos de tipus [MI2(C,C'-imz-pyr)(CH3CN)2]+ (M = Rh, Ir) (Esquema 6.13). L'estratègia sintètica per a sintetitzar estos compostos va consistir a fer reaccionar la sal d'imidazoli-piridini corresponent, [EH2]I2-[JH2]I2, amb el precursor metàl¿lic [MCl(diolefina)]2 (M = Rh, Ir; diolefina = COD, NBD) i KI en CH3CN a 65ºC durant 12h. Com a exemple la síntesi del compost 7E es mostra en l'Esquema 6.12. Les noves sals d'imidazoli-piridini, [EH2]I2-[JH2]I2, i els nous complexos metàl¿lics de Rh(III) i Ir(III), 7E-16I, descrits en aquesta secció han sigut caracteritzats per espectroscòpia d'RMN, espectrometria de masses i per anàlisi elemental. Les estructures moleculars dels complexos 11F, 14G i 15I han sigut confirmades mitjançant Difracció de Raigs-X sobre monocristall. L'avaluació de l'espectroscòpia de RMN d'aquests complexos revela algunes característiques que interessa mencionar. Pel que fa a l'espectroscòpia 13C RMN d'aquests compostos, es va observar que les freqüències degudes als carbens dels piridilidens decreixen en l'ordre: remot, normal, abnormal, per al rodi, i remot, abnormal per a l'iridi. Rodi: remot (¿c = 183.9) > normal (¿c = 175.7) > abnormal (¿c = 169.3) Iridi: remot (¿c = 164.7) > abnormal (¿c = 160.8) L'anàlisi de les longituds d'enllaç en les estructures moleculars del compostos 11F i 15I (Esquema 6.14) en han permès constatar que els piridilidens aporten una influència trans major que els imidazolilidens, com ja han suggerit altres grups d'investigació.38-39 6.3.3.2 Síntesi i caracterització dels complexos [MCp*I(C,C'-imz-pyr)]+ (M = Rh, Ir) Decidírem estendre la coordinació dels lligands derivats de les sals, [EH2]I2, [GH2]I2 i [IH2]I2, a altres precursors metàl¿lics com són [MCp*Cl2]2 (M = Rh, Ir) i una sèrie de compostos [MCp*I(C,C'-imz-pyr)]+ (M = Rh, Ir) foren sintetitzats (Esquema 6.16). L'estratègia sintètica per a sintetitzar estos compostos és similar a la utilitzada anteriorment, però en aquest es va afegir base i es va calfar a 90ºC durant 12h. Com a exemple la síntesi del compost 17E es mostra en l'Esquema 6.15. Els nous complexos metàl¿lics de Rh(III) i Ir(III), 17E-24I, descrits en aquesta secció han sigut caracteritzats per espectroscòpia d'RMN, espectrometria de masses i per anàlisi elemental. Les estructures moleculars dels complexos 18E, 19E, 20E, 22G i 23I han sigut confirmades mitjançant Difracció de Raigs-X sobre monocristall. Els compostos 20E, 22G i 23I presenten reactivitats molt inusuals. En el cas de 20E, l'imidazolilidè esta coordinat al centre metàl¿lic mentre que el piridilidè esta acoblat a l'anell de Cp*, així s'obté un anell Cp* funcionalitzat amb un imidazolilidè penjant. Pel que fa al compost 22G, a més de l'activació C-H esperada del CH3 del C2 de l'imidazoli un acoblament reductiu entre el Cp* i l'anell de piridini te lloc. Tant en el cas del complex 20E com per a 22G, creiem que aquests dos compostos se generen via la formació d'un intermedi de tetrametilfulvè de rodi. Tal com s'ha descrit per a compostos amb reactivitats similars.40-45 El compost 23I és un dímer d'iridi en el qual l'obertura de l'anell d'imidazoli ha tingut lloc com a conseqüència de la hidròlisi de l'imidazolilidè. La hidròlisi de carbens no és un fet tant estrany i ha sigut descrit en més ocasions.46 En el nostre cas, a banda de l'obertura de l'anell d'imidazolilidè, es produeixen altres reorganitzacions que tenen a veure amb la descarboxilació de l'aldehid per a generar el lligand carbonil i el lligand imino. 6.3.4 Síntesi de compostos de Rh(I) Ag(I) i Au(I) basats en lligands poli-NHC Durant aquesta tesi doctoral, també hem centrat els nostres esforços en sintetitzar compostos que contenen lligands poli-NHC. En primer lloc, varem sintetitzar i coordinar un lligand tri-NHC amb una estructura central basada en un tribenzotriquinacè (TBTQ) i amb simetria C3v a Rh(I). La segona família de compostos es va obtenir a partir de dues sals d'hexa-imidazoli, els lligands derivats d'elles es varen coordinar a Ag(I) obtenint complexos amb sis àtoms de plata en forma cilíndrica. Els compostos d'or anàlegs també es varen obtenir mitjançant transmetal¿lació. 6.3.4.1 Síntesi i caracterització del complex de Rh(I) amb el lligand tri-NHC-TBTQ L'estratègia sintètica per a preparar compostos amb lligands poli-NHC comença amb l'aminació múltiple de Buchwald-Hartwig de molècules poliaromàtiques amb bromurs adjacents. Aquesta metodologia ha sigut utilitzada per Bielawski i col¿laboradors i nosaltres aplicàrem aquesta metodologia a hexabromtribenzotriquinacè 6.547 (Esquema 6.17). D'aquesta manera, tal com es mostra en l'Esquema 6.17, el compost 6.5 reacciona amb tert-butilamina (tBuNH2) en presència de [Pd(OAc)2], IPr¿HCl i NaOtBu en toluè a 115ºC, per a donar hexaaminotribenzotriquinacè, hexaNH2-TBTQ, que posteriorment es ciclat amb trietilortoformat (HC(OEt)3) en presència de HBF4 a 80ºC, obtenint-se la sal [KH3](BF4)3. Aquesta sal es desprotonada amb KHMD en THF a 0ºC, i amb la posterior addició de [RhCl(COD)]2 a temperatura ambient s'obté el complex 25K que es purificat mitjançant cromatografia de columna. Els nous compostos, hexaNH2-TBTQ, [KH3](BF4)3 i 25K, descrits en aquesta secció han sigut caracteritzats per espectroscòpia d'RMN i espectrometria de masses. L'estructura molecular de [KH3](BF4)3 ha sigut confirmada mitjançant Difracció de Raigs-X sobre monocristall. 6.3.4.2 Síntesi i caracterització de complexos de Ag(I) i Au(I) amb lligands hexa-NHC Amb la finalitat d'augmentar el nombre d'estructures supramoleculars generades a partir de lligands poli-NHC, pensàrem que les sals 1,2,3,4,5,6-hexa(N-alquil imidazoli)benzè [LH6](OTf)6 i [MH6](BF4)6 (alquil = Me i Et, respectivament) (Esquema 6.18), podrien ser bones precursores. Aquestes sals s'obtenen a partir de l'alquilació de hexa(imidazol-1-il)benzè amb metil trifluorometasulfonat per a donar [LH6](OTf)6, o amb trietiloxoni tetrafluoroborat per a donar [MH6](BF4)6 (Esquema 6.18). La reacció d'aquestes dues sals amb Ag2O en CH3OH a 50ºC dona lloc als corresponents complexos cilíndrics, 26L i 27M, que contenen sis centres de Ag(I). Els compostos anàlegs d'or, 28L i 29M, s'obtenen mitjançant la reacció de 26L i 27M en CH3OH a 50ºC i en presència de AuCl(SMe2) (Esquema 6.18). Les noves sals, [LH6](OTf)6 i [MH6](BF4)6 i els nous complexos 26L, 27M, 28L i 29M, descrits en aquesta secció han sigut caracteritzats per espectroscòpia d'RMN i espectrometria de masses. L'estructura molecular de 28M ha sigut confirmada mitjançant Difracció de Raigs-X sobre monocristall. ¿ 6.4 CONCLUSIONS En aquesta tesi doctoral s'han obtingut una sèrie de complexos de pal¿ladi amb lligands NHC hidrofílics i complexos d'iridi amb el lligand formamidina. Aquests complexos han sigut avaluats en processos verds com són la reacció Suzuki-Miyaura d'acoblament C-C en aigua i les reaccions governades per processos de Borrowing-Hydrogen: ß-alquilació d'alcohols secundaris amb alcohols primaris i alquilació d'amoníac amb alcohols primaris. El compost 3C ha sigut el més actiu en la reacció Suzuki-Miyaura d'acoblament C-C en aigua i el compost 5D, junt amb el catalitzador d'Shvo, han presentat les millors activitats en les reaccions governades per processos de Borrowing-Hydrogen. Durant aquesta tesi doctoral, també s'han sintetitzat compostos de Rh(III) i Ir(III) amb lligands imidazolilidè-piridilidè que han presentat reactivitats molt inusuals. La comparació entre els diferents compostos obtinguts ens ha permès determinar que els piridilidens ocasionen un major efecte trans que els imidazolilidens. Finalment, s'han sintetitzat dos lligands nous poli-NHC per a la preparació de complexos polimetàl¿lics amb estructures altament simètriques. La possibilitat de preparar complexos homo-polimetàl¿lics suggereix que prompte podrem trobar la via per a sintetitzar espècies hetero-polimetàl¿liques. Per la nostra experiència, aquests complexos solen ser potencialment útils per al disseny de nous processos catalítics tàndem. A més, una de les propostes que ens hem plantejat és la combinació dels lligands piridilidens amb estructures politòpiques que obri una nova línea d'investigació dins del camp dels carbens N-heterocíclics.

Thesis (M.S. in Defense Analysis)--Naval Postgraduate School, June 2007.
Thesis Advisor(s): Peter J. Gustaitis II. "June 2007." Includes bibliographical references (p. 95-104). Also available in print.

The physicochemical properties of several novel polymorphs and amorphous forms of the antiretroviral (ARV) agents, didanosine and lopinavir, are reported. The polymorphs were prepared from recrystallisation and the glasses from cooling of the melt. These products were then characterised by means of thermal, absorption and diffraction analyses and compared to the raw material for polymorphic differences. Didanosine yielded recrystallisation products from methanol, ethanol, 1- and 2-propanol, 1- butanol and acetonitrile. Of all these, only the product obtained from methanol exhibited a powder x-ray diffraction (PXRD) pattern different from that of didanosine raw material. To investigate methanol’s capacity to produce new polymorphs of didanosine, supersaturated solutions of didanosine in water were prepared and different amounts of methanol were added as antisolvent. The crystals hereby obtained, displayed macro- and microscopic morphologies similar to that of the crystals obtained from pure methanol, however, their infrared (IR) absorption spectra and PXRD diffractograms differed slightly from those of the raw material and the crystals obtained from methanol alone. All of didanosine’s recrystallisation products from alcohols exhibited non-stoichiometric weight loss from the start of a thermogravimetric analysis (TGA), long desolvation times on hot stage micrographs and broad desolvation endothermic peaks on differential scanning calorimeter (DSC) thermograms. This lead to the conclusion that the solvent was not incorporated into channels, as is usually the case with solvates, but rather that it formed a thin film around the crystals and was present in the capillary network between the fine, elongated crystals. Upon drying the didanosine crystals from alcohols lost their morphologies and reverted back to the same polymorphic form as the raw material. The presence of solvent around the crystals was necessary for them to maintain their morphologies. This same metastability was observed upon storing of the recrystallisation products, where they started to revert back to the raw material even while under the recrystallisation medium. At around two weeks small bundles of powder formed on top of the mesh network of crystals and after one month only powder remained, analysis of this powder proved it to be the same polymorphic form as the raw material, indicating that the raw material is the most stable form of didanosine. Comparison between the results from the solubility study and scanning electron microscope (SEM) micrographs, showed an increase in solubility corresponding to a decrease in crystal size. The different crystal morphologies had no influence on the wettability or the acid lability of didanosine, a direct result of the film of solvent coating the crystals. Any liquid that came into contact with the crystals was automatically dispersed across its surface. Lopinavir formed several recrystallisation products including large hexagonal plates from acetone, long hexagonal staffs from ethyl acetate, needles from diethyl ether and resins from chloroform and dichloromethane. Initial thermal analysis showed all the recrystallisation products, even the more crystalline ones, to be at least partially amorphous. For comparative purposes, two additional glasses were prepared from cooling of the melt. One was cooled at ambient temperature and the other was quench cooled using liquid nitrogen. Activation energies for β-relaxations (ΔEβ) and glass transitions were calculated from non-isothermal kinetics data obtained by DSC and from the activation energies for glass transition of each sample, the fragility (m) and strength (D) parameters of each sample were calculated. Comparisons between the ΔEβ and m were in excellent coherence to the macro- and microscopic characteristics of each sample and offered valuable insight into certain physical behaviour. The amorphous content of each sample was determined by means of DSC and Fourier transform infrared (FTIR) spectroscopy. Results from the solubility study exhibited little coherence with the crystalline/amorphous content of the samples analysed as well as with the m and D values. There was however, an inverse correlation between the solubility and the ΔEβ of each sample, suggesting that the increased local molecular motilities of the samples with low ΔEβ values (and the subsequent decrease of the contact angle), facilitated dissolution from these regions, leading to surface roughening and an increasing in effective surface area. The progression of this process, resulting from the ongoing coupling of the β- relaxations, eventually increased the solubility of the samples exhibiting the lowest ΔEβ values.
Thesis (Ph.D. (Pharmaceutics))--North-West University, Potchefstroom Campus, 2012

The purpose of this thesis is to explore an alternative strategic focus for the Department of Defense to implement in the conduct of the Global War on Terrorism. Our thesis is as follows: A non-conventional approach to strategic policy, led by an enhanced Foreign Internal Defense concept, and judicious execution of U.S. Sponsored Unconventional Warfare, applied as a primary tool of U.S. national policy through the Department of Defense, will serve as an effective solution to the global "terrorist" threat. This paper will justify such by analyzing the historical conduct of the United States through the framework of its own doctrine and the "Mystic Diamond" a State/Counter-state dynamic model as presented by Dr. Gordon McCormick. Elements of the Department of Defense and the Department of State know the operational strategy to take, but are hampered by the misapplication of counter-guerilla tactics as strategy, and are reluctant to use sponsored UW to preempt or curtail the exportation of terrorism. In essence, the Department of Defense has been and continues to be limited by its conventional tactical successes, when what is required is strategic application of FID, UW, and limited Direct Engagement to defeat an enemy employing a non-conventional method of engagement.

Cette thèse de doctorat porte principalement sur la dynamique et la robustesse d’un nouveau concept de verrouillage de mode dans les nanolasers semi-conducteurs ultracompacts. Un tel nanolaser présente des modes ermites-gaussiens créés par une cavité photonique harmonique pour confiner la lumière. Cela permet de mapper la cavité optique en oscillateur harmonique de mécanique quantique, avec des fréquences propres régulièrement espacées, une condition essentielle pour le verrouillage de mode. La période de verrouillage de mode est contrôlée par la conception du potentiel photonique, et non par la longueur de la cavité. Les régimes non linéaires possibles sont décrits par l’équation de Gross-Pitaevskii avec un potentiel parabolique et des termes non linéaires décrivant le gain et l’absorption. Pour étudier ces comportements dynamiques, des simulations numériques directes sont principalement mises en œuvre. Tout d’abord, la compétition de mode pour le gain entre les modes ermites et gaussiens en l’absence d’absorption saturable est étudiée. Deuxièmement, on prévoit que le verrouillage des modes se produira avec une saturation instantanée du gain et de l’absorption sur un large éventail de paramètres, correspondant à l’émergence d’une soliton dissipative. Troisièmement, dans le régime de saturation non instantanée du gain et de l’absorption, différents comportements dynamiques du nanolaser sont obtenus en faisant varier le gain et l’absorption. Ces différents régimes, y compris la commutation Q, le verrouillage de mode à commutation Q et le verrouillage de mode CW, sont décrits en détail. L’influence du facteur Henry sur le verrouillage de mode est également abordée. Quatrièmement, la robustesse du verrouillage de mode des modes ermite et gaussien au désordre de la cavité harmonique est étudiée en détail, y compris l’effet de la non-parabolicité du potentiel et les erreurs aléatoires dans la forme du potentiel
This PhD thesis mainly addresses the dynamics and the robustness of a novel concept of mode locking in ultracompact semiconductor nanolasers. Such a nanolaser exhibits Hermite-Gaussian modes created by a harmonic photonic cavity to confine light. This maps the optical cavity into quantum mechanical harmonic oscillator, with evenly spaced eigenfrequencies, an essential requirement for mode locking. The possible nonlinear regimes are described by the Gross-Pitaevskii equation with a parabolic potential and nonlinear terms describing gain and absorption. To investigate these dynamical behaviors, direct numerical simulations are mainly implemented. Continuation calculations are also performed using pde2path.First, the mode competition for gain among Hermite-Gaussian modes in the absence of saturable absorption is investigated and shown to be very different from usual resonators.Second, mode locking is predicted to occur with instantaneous saturation of gain and absorption over a broad range of parameters, corresponding to the emergence of dissipative soliton and multisoliton solutions. The mode locking period is controlled by the design of the photonic potential, and not by the cavity length. The dissipative soliton is well described by the coherent state of a quantum mechanical oscillator, namely a Gaussian envelope oscillating without deformation.Third, in the regime of noninstantaneous gain and absorption saturation, different dynamical behaviors of the nanolaser are obtained by varying the gain and the absorption. These different regimes, including Q-switching, Q-switched mode locking, and CW mode locking, are described in detail, illustrating the rich physics of this nonlinear system. The influence of the Henry factor on the mode locking is also discussed. Moreover, similar dynamical behaviors using spatially separated gain and absorber sections inside the cavity are obtained.Fourth, the robustness of mode locking of the Hermite-Gaussian modes to the disorder of the harmonic cavity is investigated in details. It includes the effect of non-parabolicity of the potential and the random errors in the shape of the potential

This thesis presents the development of calibration and data-reduction algorithms for non-conventional multi-hole pressure probes. The algorithms that have been developed for conventional 5- and 7-hole probes are not optimal for probes with port arrangements (on the probe tip) that are non-conventional. Conventional algorithms utilize the axisymmetry of the port distribution pattern to define the non-dimensional pressure coefficients. These coefficients are typically defined specifically for these patterns, but fail to correctly represent different patterns of port arrangements, such as patterns without axisymmetry or regularity. The algorithms introduced herein can handle any pattern of port arrangement, from axisymmetric and regular to random. Moreover, they eliminate the need to separate the measurement domain of a probe to "low-angle" and "high-angle" regimes, typical in conventional 5- and 7-hole-probe algorithms that require two different sets of pressure coefficient definitions and procedures. Additionally, the algorithms have been formulated such that they facilitate redundancy implementations, especially in applications where such redundancy is important, such as air-data systems. The developed algorithms are first applied to a non-conventional probe, a nearly omni-directional 18-hole probe, and demonstrate very high flow measurement accuracy. Subsequently, the algorithms were applied to a new 12-hole, nearly omni-directional, flow velocity measurement probe capable of measuring reversed flows. The new 12-hole design offers several advantages over a previously developed, 18-hole, nearly omni-directional probe. The probe is optimized in the sense that, regardless of the flow direction, it allows calculation of the 4 unknown flow quantities, i.e. the two flow angles, the velocity magnitude and the static pressure, with the minimum necessary number of holes/ports on the probe tip. This probe also has a non-conventional arrangement of its pressure ports and therefore the new calibration and data-reduction algorithms can be effectively employed. With theoretically generated pressure data for the 12-hole probe, the coefficient definitions are analyzed and found to be well-behaved.