Rapid prototyping is a relativity new technology and is based on layered manufacturing which has similarities to the method an ordinary desktop paper printer works. This research is to obtain a better understanding on how to use computer graphics software, in this particular case Autodesk Maya, to create a model. The goal is to understand how to create a suitable mesh of a 3D model for use with a 3D printer and produce a printed model that is equivalent to the CAD software 3D model. This specific topic has not been scientifically documented which has resulted in an actual 3D model.

Ce travail de thèse s’inscrit dans le contexte identifié de la nécessité de développer de nouveaux polymères plus respectueux de l’environnement. Nous sommes convaincus que l’essor de ces matériaux « verts » exige d’utiliser des additifs « verts » lors de la formulation. Dans le but d’élaborer des additifs respectueux de l’environnement capables d’assurer la stabilisation du polymère au regard du cycle de vie, et en attachant une attention particulière à la valorisation de la biomasse, trois approches ont été étudiées. La première est une voie innovante qui consiste à utiliser un mélange de polyphénols issus des sous-produits de l’industrie vinicole, et de l’industrie du thé. La seconde voie est la valorisation d’une molécule issue du sous-produit majeur de l’industrie du blé. La troisième est une voie d’innovation récente, qui propose l’utilisation de nanocomposites hydroxydes doubles lamellaires (HDL) fonctionnalisés avec des stabilisants biosourcés. L’évaluation de leurs propriétés stabilisantes, est réalisée au regard des processus de thermo- et photo-oxydation, dans les polyoléfines. Les résultats très prometteurs de ce projet mettent en évidence le fort potentiel des molécules et composites d’origine biosourcée à maintenir les propriétés des polymères en conditions d’usages. / This thesis work falls within the identified context of the need to develop new polymers that are more environmentally friendly. We are convinced that the development of these "green" materials requires the use of "green" additives during formulation. To develop environmentally friendly additives capable of stabilizing the polymer, with respect to the life cycle, and paying special attention to biomass valorization, three approaches have been studied. The first is an innovative way of using a mixture of polyphenols from winery by-products and tea industry. The second way is the valorisation of a molecule from the major by-product of the wheat industry. The third is a recent route of innovation, which proposes the use of layered double hydroxides nanocomposites (LDH) functionalized with bio based stabilizers. The evaluation of their stabilizing properties is carried out in polyolefins, against thermo- and photo-oxidation processes. The very promising results of the project highlight the strong potential of bio based molecules and composites to maintain polymers properties under conditions of use.

Les matériaux hydroxydes doubles lamellaires (HDL) sont une classe d'argiles anioniques synthétiques dont la structure est basée sur celle du brucite Mg(OH)2 dans lesquelles une partie des cations métalliques divalents sont été remplacés par des ions trivalents donnant ainsi des feuillets chargés positive. Cette charge est équilibrée par l'intercalation d'anions dans la région interlamellaire hydratée. Les identités et les rapports des cations di- et trivalents et l'anion interlamellaire peuvent être varié sur une large gamme, donnant lieu à une large classe de matériaux isostructurales. Le matériau d’origine de cette classe est l’hydrotalcite (HT) et les HDL sont par conséquent également connus comme des matériaux de type hydrotalcite. Bien que les caractéristiques de base de la structure soient bien comprises, des aspects structurels détaillés ont fait l'objet de certaine controverse dans la littérature afin de maîtriser leurs propriétés et leurs applications potentielles. Dans ce travail de thèse nous avons retenu deux types de HDL MgAl et ZnAl qui ont été largement introduits dans diverses applications, tels que la sorption des molécules d'intérêt biologique (enzyme et médicament) et l'élaboration d'électrodes. La spécificité de ce travail repose sur l’immobilisation d’une enzyme modèle, la lactate déshydrogénase dans ces deux matrices ainsi qu’un médicament anti-bactérien, la berbérine, afin d’étudier les interactions entre ces deux biomolécules et la phase HDL introduite et de répondre à leurs exigences d'applications dans le domaine médical. Dans un second temps nous avons tenté d’étudier les deux phases mentionnées de plus en plus fine en termes de structure, morphologie et profil électrochimique en vue de les employer en tant que matériaux d’électrode pour le développement de biopile / DHs are a class of synthetic anionic clays whose structure is based on brucite-like layers Mg(OH)2 inwhich some of the divalent cations have been replaced by trivalent ions giving positively-charged sheets.This charge is balanced by intercalation of anions in the hydrated interlayer regions. The identities andratios of the di- and trivalent cations and the interlayer anion may be varied over a wide range, giving rise toa large class of isostructural materials. The parent material of this class is the naturally occurring mineralhydrotalcite and LDHs are consequently also known as hydrotalcite-like materials. Although the basicfeatures of the structure are well understood, detailed structural aspects have been the subject of somecontroversy in the literature. In this thesis, we have selected two types of LDH, MgAl and ZnAl, which havebeen widely introduced in various applications, such as sorption of molecules of biological interest (enzymeand drug) and the development of electrodes. The specificity of this work lies on the immobilization of amodel enzyme, lactate dehydrogenase in both matrices as well as an anti-bacterial drug, berberine, inorder to study the interactions between these two biomolecules and the introduced LDH phase and tobetter address their challenges of applications in the medical field. Second, we have tried to study the twophases mentioned above more and more accurately in terms of structure, morphology and electrochemicalprofile in order to use them as electrode materials for microbial fuel cell device

Das bei der Sanierung von großen segmentalen Knochendefekten bestehende Risiko einer fremdkörperassoziierten Infektion soll durch die Integration eines Wirkstofffreisetzungssystems in ein bestehendes textiles Knochenimplantat gemindert werden. Durch Immobilisierung des Wirkstoffs in eine degradierbare Polymermatrix wird eine zeitlich verzögerte Freisetzung bewirkt. Als Wirkstofffreisetzungssystem wird die Kombination von Polylactid (PLA) bzw. Poly(Lactid-co-Glycolid) (PLGA) als Matrixpolymer mit dem Antibiotikum Gentamicin als Wirkstoff untersucht, welches durch Beschichtung der textilen Scaffolds mittels Dip-Coating eingebracht werden soll. Es stehen die drei Beschichtungsmethoden „Suspension“, „Emulsion“ und „Schichtaufbau“ zur Auswahl, die jeweils über eigene Parameter zur Beeinflussung des Freisetzungsprofils verfügen. Die Methode „Suspension“ und die damit verbundenen Einflussfaktoren Korngröße, Korngrößenverteilung sowie Masseanteil des Antibiotikums und Schichtdicke der aufgetragenen Polymerschicht wurde als die günstigste herausgearbeitet. Im Teil II dieser Arbeit wird diese soweit optimiert, dass nahezu über den gesamten geforderten Zeitraum die festgelegte notwendige Dosierung aufrechterhalten werden kann. Erste in vitro Versuche weisen auf eine gute Zellverträglichkeit sowie eine ausreichende mikrobielle Wirksamkeit hin. / To reduce the risk of infection in the treatment of long bone defects, a novel embroidered bone implant is to be provided with an antibiotic drug delivery system. Prolonged and controlled drug release can be achieved by coating the thread material with antibiotics incorporated in a degradable polymer matrix. The chosen drug delivery system is composed of polylactide acid (PLA) or poly(lactide-co-glycolide) acid (PLGA) as matrix polymer and the antibiotic gentamicin. It is integrated into the textile structure by dip-coating providing the three different methods suspension, emulsion and layered. Each method bears its appropriate parameters to influence the releasing profile. The suspension-method and its parameters grain size and grain size distribution as well as mass fraction of the antibiotic and the coating thickness could be proved as the most feasible. In part II of this essay the chosen coating set-up gets optimized so that a drug release nearly along the whole required term can be achieved. Preliminary in vitro studies show a good cell tolerance besides a sufficient microbial efficacy.

L'objectif de ce travail de thèse est de préparer des latex nanocomposites à base d’argile, la Laponite RD, en émulsion aqueuse, à l'aide de la polymérisation radicalaire contrôlée par transfert de chaîne réversible par addition-fragmentation (RAFT). Les plaquettes de Laponite ont été choisies comme charge inorganique surtout pour leur anisotropie de forme, ce qui pourrait permettre l’elaboration de films nanostructurés, mais aussi pour leurs propriétés thermiques et mécaniques, leur pureté chimique élevée et la distribution uniforme en taille des plaquettes. Des polymères hydrophiles (macroRAFT) à base de polyéthylène glycol (PEG), d’acide acrylique (AA) ou de méthacrylate de N,N- diméthylaminoéthyle (DMAEMA) et comportant des unités hydrophobes d’acrylate de n-butyle (ABu) (dans certains cas) et un groupe trithiocarbonate terminal, ont été tout d'abord synthétisés. Ensuite, l'interaction entre les macroRAFTs et l’argile a été étudiée à travers le tracé des isothermes d'adsorption. En agissant comme des agents de couplage et des stabilisants, ces macroRAFTs ont eté utilisés dans la copolymérisation en émulsion du (méth)acrylate de méthyle et de l’ABu en mode semi-continu en presence d’argile. Des particules de latex hybrides de différentes morphologies ont été obtenues et les morphologies ont été reliées à la nature et à la concentration de l’agent macroRAFT, au pH de la dispersion macroRAFT/Laponite, à la température de transition vitreuse du copolymère final (fonction de la composition du mélange de monomères hydrophobes) et aux conditions de polymérisation. Les analyses par cryo-MET indiquent des plaquettes de Laponite décorées par des particules de polymère (plusieurs particules de latex en surface des plaquettes d'argile), des particules ‘haltère’, janus, ‘carapace’ (particules de latex décorées en surface par les plaquettes de Laponite) ou encore des particules multi-encapsulées (plusieurs plaquettes encapsulées dans chaque particule de latex). Les propriétés mécaniques des films de polymère/Laponite ont été étudiées par spectrométrie mécanique dynamique et corrélées à la morphologie des particules et à la microstructure des films / The aim of this work is to prepare Laponite RD-based nanocomposite latexes by aqueous emulsion polymerization, using the reversible addition-fragmentation chain transfer (RAFT) polymerization. Laponite platelets were selected as the inorganic filler due, especially, to their anisotropic shape, which allows the production of nanostructured films, but also for their thermal and mechanical properties, their high chemical purity and the uniform dispersity of the platelets. Hydrophilic polymers (macroRAFT) composed of poly(ethylene glycol) (PEG), acrylic acid (AA) or N,N-dimethylaminoethyl methacrylate (DMAEMA) and comprising hydrophobic n-butyl acrylate (BA) units (in some cases) and trithiocarbonate terminal group were initially synthesized. Then, the interaction between the macroRAFTs and the clay was studied through the plot of adsorption isotherms. By acting as coupling agents and stabilizers, the macroRAFT agents were used in the emulsion copolymerization of methyl (meth)acrylate and BA by semi-continuous process in the presence of the clay. Hybrid latex particles with different morphologies were obtained and the results were associated to the nature and concentration of the RAFT (co)polymers, to the pH of the macroRAFT/Laponite dispersion, the glass transition temperature of the final copolymer (function of the composition of the hydrophobic monomers mixture) and to the polymerization conditions. The cryo-TEM images indicate the formation of polymerdecorated Laponite platelets (several latex particles located at the surface of the platelets), dumbbell-like, janus, Laponite-decorated (armored) latex particles, and multiple encapsulated particles (several platelets inside each latex particle). The mechanical properties of polymer/Laponite films were studied by dynamic mechanical analysis and correlated with the particles morphology and the films microstructure / Este trabalho de tese tem como objetivo a preparação de látices nanocompósitos à base da argila Laponita RD em emulsão aquosa, via polimerização radicalar controlada por transferência de cadeia via adição-fragmentação reversível (RAFT). A Laponita foi escolhida como carga inorgânica devido principalmente à forma anisotrópica de suas lamelas, o que permite a elaboração de filmes nanoestruturados, mas também por suas propriedades térmicas e mecânicas, por sua alta pureza química e pela distribuição uniforme, em termos de tamanho, de suas partículas. Inicialmente, polímeros hidrofílicos (macroRAFT) à base de poli(etileno glicol) (PEG), de ácido acrílico (AA) ou de metacrilato de N,N-dimetilaminoetila (DMAEMA) que contêm unidades hidrofóbicas de acrilato de nbutila (ABu) (em alguns casos) e um grupo tritiocarbonílico terminal foram sintetizados. Em seguida, a interação entre os macroagentes de controle (macroRAFTs) e a argila foi estudada através de isotermas de adsorção. Atuando como agentes de acoplamento e estabilizantes, esses macroRAFTs foram então utilizados na copolimerização em emulsão do (met)acrilato de metila e do ABu em processo semicontínuo na presença da argila Laponita. Partículas de látex híbrido de diferentes morfologias foram obtidas e os resultados foram correlacionados à natureza e à concentração dos macroRAFTs, ao pH da dispersão macroRAFT/Laponita, à temperatura de transição vítrea do copolímero final (função da composição da mistura de monômeros hidrofóbicos) e às condições de polimerização. As análises de cryo-TEM indicam a formação de lamelas de Laponita decoradas com partículas de polímero (várias partículas de látex localizadas na superfície das lamelas), de partículas do tipo dumbbell, janus, blindadas (partículas de látex decoradas com lamelas de argila em sua superfície) ou ainda de partículas multiencapsuladas (diversas lamelas encapsuladas dentro de uma única partícula de látex). As propriedades mecânicas dos filmes de polímero/Laponita foram estudadas por análise dinâmico-mecânica e correlacionadas à morfologia das partículas e à microestrutura dos filmes

Ces travaux de thèse pluridisciplinaires à l‘interface entre biocatalyse et nanomatériaux visent la conception de matériaux biohybrides innovants par assemblage dans des conditions douces de matériaux inorganiques de type hydroxydes doubles lamellaires (HDL) avec des enzymes. La première partie de ce mémoire est consacrée à la caractérisation des interactions physico-chimiques entre les HDL et la fructose-6-phosphate aldolase (FSA) catalysant la formation stéréosélective de liaisons C-C pour conduire à des polyols chiraux. Les structures lamellaires HDL permettent un confinement efficace de systèmes enzymatiques grâce à leur structure bidimensionnelle poreuse, leurs propriétés physico-chimiques favorables à l‘échange ionique et leur biocompatibilité. Différentes stratégies d‘immobilisation de la FSA dans des matrices d‘HDL ont été explorées, le taux d‘immobilisation et l‘activité biocatalytique étant fortement dépendant de la méthode d‘assemblage et de la nature des phases HDL. Le taux d‘immobilisation de l‘enzyme obtenu par coprécipitaton est supérieur à celui obtenu par adsorption. Dans une deuxième partie, un bioréacteur a été élaboré par un assemblage hiérarchisé constitué de la FSA, de nanoplaquettes d‘HDL et de billes de polysaccharide, ce dernier jouant le rôle de matrice macrostructurante. De façon notable, le taux d‘encapsulation de l‘enzyme dans la matrice macroscopique est amélioré lorsque le biocatalyseur est pré-encapsulé dans les nanoplaquettes d‘HDL. Ceci est attribué aux interactions électrostatiques favorables entre les chaînes de polysaccharide et les HDL, facilitant une charge de matière plus importante. L‘efficacité catalytique du bioréacteur obtenu et sa recyclabilité ont été démontrés. Dans la troisième partie de cette thèse, nous décrivons pour la première fois la conception de bionanoréacteurs enzymes@HDL par co-immobilisation de systèmes bi- ou tétra-enzymatiques dans les HDL permettant de réaliser des cascades multienzymatiques biomimétiques. L‘immobilisation des différentes enzymes prises séparément a d‘abord été optimisée afin de déterminer les conditions de co-immobilisation et de réaliser les cascades biocatalytiques en phase hétérogène. Ces bionanoréacteurs, dont nous avons démontré la recyclabilité, ont été appliqués pour la synthèse de sucres phosphorylés de série D. Enfin, une cascade multienzymatique a été conçue de novo en solution aqueuse et optimisée pour synthétiser différents sucres phosphorylés rares de série L. / This multidisciplinary thesis at the biocatalysis/nanomaterial interface perfectly aims at designing innovative biohybrid materials by the assembly of inorganic materials the Layered Double Hydroxides (LDH) with enzymes under mild conditions. The first part of this thesis is devoted to the characterization of physico-chemical interactions between the LDH and the fructose-6-phosphate aldolase (FSA) catalyzing the stereoselective C-C bond formation to provide chiral polyols. LDH structures allow the effective confinement of enzymatic systems thanks to their opened two-dimensional structure as well as their chemical surface properties at the nanoscale and their biocompatibility. The FSA immobilization in different LDH matrices by different methods was studied. Biocatalytic activity is highly dependent on the method of assembling, modulating the final amount of FSA. The retaining activity rate of co-precipitated material was higher than that obtained for the adsorbed enzyme. In a second part, a bionanoreactor was developed based on a hierarchized assembly of FSA, LDH nanoplatelets and polysaccharide beads acting as a macrostructuring matrices. Significantly, the encapsulated enzyme rate in the beads was improved when the biocatalyst was pre-encapsulated in LDH nanoplatelets. This is attributed to favorable electrostatic interactions between the polysaccharide chains and LDH, facilitating a higher catalyst loading. The catalytic efficiency of the prepared bioreactor and its recyclability were demonstrated. In the third part of this thesis, we describe for the first time the design of bionanoreactors ―enzymes@LDH‖ by co-immobilisation of two and four enzymes in LDH allowing biomimetic multienzymatic cascades. We first studied the immobilization of the different enzymes taken separately. Then we worked on the optimization of the biocatalytic cascades in heterogeneous phase. These bionanoreactors, for which we have shown the recyclability, have been applied to the synthesis of D-series phosphorylated sugars. Finally, a multienzymatic cascade was de novo designed in aqueous homogeneous solution. It was optimized for the synthesis of rare L-phosphorylated sugars.

Transition metals (TMs) are ‘elements whose atoms have partially filled d-shell, or which can give rise to cations with an incomplete d-shell’. In TMs, the d-shell overlaps with next higher s-shell. Most of the TMs exhibit more than one (multiple) oxidation states. Some TMs, such as silver and gold, occur naturally in their metallic state but, most of the TM minerals are generally oxides. Most of the minerals on the planet earth are metal oxides, because of large free energies of formation for the oxides. The thermodynamic stability of the oxides is determined from the Ellingham diagram. Ellingham diagram shows the temperature dependence of the stability (free energy) for binaries such as metal oxides. Ellingham diagram also shows the ease of reducibility of metal oxides. TM oxides of general formulas MO, M2O3, MO2, M2O5, MO3 are known to exist, many of them being the ultimate products of oxidation in air in their highest oxidation states. In addition, TM oxides also exist in lower oxidation states which are prepared under controlled conditions. The nature of bonding in these oxides varies from mainly ionic (e.g. NiO, CoO) to mainly covalent (e.g. OsO4). Simple binary oxides of the compositions, MO, generally possess the rock salt structure (e.g. NiO), while the dioxides, MO2, possess the rutile structure (e.g. TiO2); many sesquioxides, M2O3, possess the corundum structure (e.g. Cr2O3). TMs form important ternary oxides like perovskites (e.g. CaTiO3), spinels (e.g. MgFe2O4) and so on. In TM oxides, the valence (outer) d-shell could be empty, d0 (e. g. TiO2), partially filled, dn (1≤ n≤ 9) (e.g. TiO, VO, NiO etc.) or completely filled, d10 (e.g. ZnO, CdO, Cu2O etc.). The outer d electrons in TM oxides could be localized or delocalized. Localized outer d electrons give insulators/semiconductors, while delocalized/itinerant d electrons make the TM oxide ‘metallic’ (e.g. ReO3, RuO2). Partially filled dn states are normally expected to give rise to itinerant (metallic) electron behaviour. But most of TM oxides with partially filled d shell are insulators because of special electronic energy (correlation energy) involved in d electron transfer to adjacent sites. Such insulating TM oxides are known as Mott insulators (e. g. NiO, CoO etc.). Certain TM oxides are known to exhibit both localized (insulating) and itinerant (metallic) behaviour as a function of temperature or pressure. For example, VO2 shows a insulator–metal transition at ~340K. Similar transitions are also known for V2O3, metal-rich EuO and so on. The chemical composition and bonding of TM oxides, which determine the crystal and electronic structures, give rise to functional properties. Table 1 gives representative examples. Properties like ionic conductivity and diffusion are governed by both the crystal structure and the defect structure (point defects), whereas properties such as magnetism and electron transport mainly arise from the electronic structures of the materials. Accordingly, TM oxides provide a platform for exploring functional materials properties. Among the various functional materials properties exhibited by transition metal oxides, the present thesis is devoted to investigations of lithium ion battery cathodes, inorganic pigments and magnetic perovskites. Over the years, most of the lithium containing first row transition metal oxides of rock salt derived structure have been investigated for possible application as cathode materials in lithium ion batteries (LIBs). First major breakthrough in LIBs research was achieved by electrochemically deinserting and inserting lithium in LiCoO2. A new series of cathode materials for LIBs were prepared by incorporating excess lithium into the transition metal containing layered lithium oxides through solid solution formation between Li2MnO3–LiMO2 (M = Cr, Mn, Fe, Co, Ni), known as lithium-rich layered oxides (LLOs). LLOs exhibit improved electrochemical performance as compared to the corresponding end members and hence received significant attention as a potential next generation cathode materials for LIBs in recent times. LiCoO2 (R-3m) crystallizes in the layered α-NaFeO2 structure with the oxygens in a ccp arrangement. Li+ and Co3+ ions almost perfectly order in the octahedral sites (3a and 3b) to give alternating (111) planes of LiO6 and CoO6 octahedra. Table 1. Materials properties exhibited by representative TM oxides. Property Example(s) Ferroelectricity BaTiO3, PbTiO3, Bi4Ti3O12 Nonlinear Optical Response LiNbO3 Multiferroic response BiFeO3, TbMnO3 Microwave dielectric properties Ba3ZnTa2O9 Relaxor Dielectric Properties Pb3MgNb2O9, Colossal Magnetoresistance Tl2Mn2O7 Metallic ‘Ferroelectricity’ Cd2Re2O7 Superconductivity AOs2O6(A = K, Rb, Cs) Redox deinsertion/insertion of LiCoO2 lithium Photocatalysis/water splitting TiO2 Pigment Ca(1-x)LaxTaO(2-x)N1+x (yellow-red), YIn1-xMnxO3 (blue) Metallic Ferromagnetism CrO2 Antiferromagnetism NiO, LaFeO3 Zero thermal expansion ZrW2O8 The reversible capacity of LiCoO2 in common LIBs is relatively low at around 140 mA h g-1 (half of theoretical capacity), corresponding to: LiCo3+O2 → Li0.5Co3+0.5Co4+0.5O2 + 0.5Li+ + 0.5e– . Substitution of one or more transition metal ions in LiCOO2 has been explored to improve the electrochemical performance. The structure of LLOs is described as a solid solution or nano composite of Li2MnO3 (C2/m) and LiMO2 (R-3m). The electrochemical deinsertion/insertion behaviour of LLOs is complex and also not yet understood completely. The present thesis consists of four parts. After a brief introduction (Part 1), Part 2 is devoted to materials for Li-ion battery cathode, consisting of three Chapters 2.1, 2.2 and 2.3. In Chapter 2.1, we describe the synthesis, crystal structure, magnetic and electrochemical characterization of new LiCoO2 type rock salt oxides of formula, Li3M2RuO6 (M = Co, Ni). The M =Co oxide adopts the LiCoO2 (R-3m) structure, whereas the M = Ni oxide also adopts a similar layered structure related to Li2TiO3. Magnetic susceptibility measurements reveal that in Li3Co2RuO6, the oxidation states of transition metal ions are Co3+, Co2+ and Ru4+, whereas in Li3Ni2RuO6, the oxidation states are Ni2+ and Ru5+. Li3Co2RuO6 orders antiferromagnetically at ~10K. On the other hand, Li3Ni2RuO6 presents a ferrimagnetic behaviour with a Curie temperature of ~100K. Electrochemical Li-deinsertion/insertion studies show that high first charge capacities (between ca.160 and 180 mA h g−1) corresponding to ca.2/3 of theoretical capacity are reached albeit, in both cases, capacity retention and cyclability are not satisfactory. Chapter 2.2 presents a study of new ruthenium containing LLOs, Li3MRuO5 (M = Co and Ni). Both the oxides crystallize in the layered LLO type LiCoO2 (α-NaFeO2) structure consisting of Li[Li0.2M0.4Ru0.4]O2 layers. Magnetic susceptibility data suggest that the oxidation states of transition metals are Li3Co3+Ru4+O5 for the M = Co compound and Li3Ni2+Ru5+O5 for the M = Ni compound. Electrochemical investigations of lithium deintercalation–intercalation behaviour reveal that both Co and Ni phases exhibit attractive specific capacities of ca. 200 mA h g-1 at an average voltage of 4 V, that has been interpreted as due to the oxidation of Co3+ and Ru4+ in Li3CoRuO5 and Ni2+ to Ni4+ in the case of Li3NiRuO5. Thus, we find that ruthenium plays a favourable role in LLOs than in non-LLOs in stabilizing higher reversible electrochemical capacities. In Chapter 2.3, we describe the synthesis, crystal structure and lithium deinsertion–insertion electrochemistry of two new LLOs, Li3MRuO5 (M=Mn, Fe) which are analogs of the oxides described in Chapter 2.2. The Li3MnRuO5 oxide adopts a structure related to Li2MnO3 (C2/m), while the Li3FeRuO5 oxide adopts a near-perfect LiCoO2 (R-3m) structure. Lithium electrochemistry shows typical behaviour of LLOs for both oxides, where participation of oxide ions in the electrochemical processes is observed. A long first charge process with capacities of 240 mA h g-1 (2.3 Li per f.u.) and 144 mA h g-1 (1.38 Li per f.u.) is observed for Li3MnRuO5 and Li3FeRuO5, respectively. Further discharge–charge cycling points to partial reversibility. X-ray photoelectron spectroscopy (XPS) characterisation of both pristine and electrochemically oxidized Li3MRuO5 reveals that in the Li3MnRuO5 oxide, Mn3+ and Ru4+ are partially oxidized to Mn4+ and Ru5+ in the sloping region at low voltage, while in the long plateau, O2- is also oxidized. In the Li3FeRuO5 oxide, the oxidation process appears to affect only Ru (4+ to 5+ in the sloping region) and O2- (plateau), while Fe seems to retain its 3+ state. Another characteristic feature of TMs is formation of several coloured solid materials where d–d transitions, band gap transitions and charge transfer transitions are involved in the colouration mechanism. Coloured TM oxides absorbing visible light find important applications as visible light photocatalyst (for example, yellow BiVO4 for solar water splitting and red Sr1-xNbO3 for oxidation of methylene blue) and inorganic pigments [for example, Egyptian blue (CaCuSi4O10), Malachite green (Cu2CO3(OH)2), Ochre red (Fe2O3)]. Pigments are applied as colouring materials in inks, dyes, paints, plastics, ceramic glazers, enamels and textiles. In this thesis, we have focused on the coloured TM oxides for possible application as inorganic pigments. Generally, colours arise from electronic transitions that absorb visible light. Colours of the inorganic pigments arise mainly from electronic transitions involving TM ions in various ligand fields and charge transfer transitions governed by different selection rules. The ligand field d–d transitions are parity forbidden but are relaxed due to various reasons, such as distortion (absence of center of inversion) and vibronic coupling. The d-electrons can be excited by light absorption in the visible region of the spectrum imparting colour to the material. Charge transfer transitions in the visible region are not restricted by the parity selection rules and therefore give intense colours. Here we have investigated the colours of manganese in unusual oxidation state (Mn5+) as well as the colours of different 3d-TM ions in distorted octahedral and trigonal prismatic sites in appropriate colourless crystalline host oxides. These results are discussed in Part 3 of the thesis. In Chapter 3.1, we describe a blue/green inorganic material, Ba3(P1−xMnxO4)2 (I) based on tetrahedral Mn5+O4 :3d2 chromophore. The solid solutions (I) which are sky-blue and turquoise-blue for x ≤ 0•25 and dark green for x ≥ 0•50, are readily synthesized in air from commonly available starting materials, stabilizing the Mn5+O4 chromophore in an isostructural phosphate host. We suggest that the covalency/ionicity of P–O/Mn–O bonds in the solid solutions tunes the crystal field strength around Mn(V) such that a blue colour results for materials with small values of x. The material could serve as a nontoxic blue/green inorganic pigment. In Chapter 3.2, an experimental investigation of the stabilization of the turquoise-coloured Mn5+O4 chromophore in various oxide hosts, viz., A3(VO4)2 (A = Ba, Sr, Ca), YVO4, and Ba2MO4 (M = Ti, Si), has been carried out. The results reveal that substitution of Mn5+O4 occurs in Ba3(VO4)2 forming the entire solid solution series Ba3(V1−xMnxO4)2 (0 < x ≤ 1.0), while, with the corresponding strontium derivative, only up to about 10% of Mn5+O4 substitution is possible. Ca3(VO4)2 and YVO4 do not stabilize Mn5+O4 at all. With Ba2MO4 (M = Ti, Si), we could prepare only partially substituted materials, Ba2M1−xMn5+xO4+x/2 for x up to 0.15, that are turquoise-coloured. We rationalize the results that a large stabilization of the O 2p-valence band states occurs in the presence of the electropositive barium that renders the Mn5+ oxidation state accessible in oxoanion compounds containing PO43−, VO43−, etc. By way of proof-of-concept, we synthesized new turquoise-coloured Mn5+O4 materials, Ba5(BO3)(MnO4)2Cl and Ba5(BO3)(PO4)(MnO4)Cl, based on the apatite – Ba5(PO4)3Cl – structure. Chapter 3.3 discusses crystal structures, and optical absorption spectra/colours of 3d-transition metal substituted lyonsite type oxides, Li3Al1-xMIIIx(MoO4)3 (0< x ≤1.0) (MIII = Cr, Fe) and Li3-xAl1-xMII2x(MoO4)3 (0< x ≤1.0) (MII = Co, Ni, Cu). Crystal structures determined from Rietveld refinement of PXRD data reveal that in the smaller trivalent metal substituted lyonsite oxides, MIII ions occupy the octahedral (8d, 4c) sites and the lithium ions exclusively occur at the trigonal prismatic (4c) site in the orthorhombic (Pnma) structure; on the other hand, larger divalent cations (CoII/CuII) substituted derivatives show occupancy of CoII/CuII ions at both the octahedral and trigonal prismatic sites. We have investigated the colours and optical absorption spectra of Li3Al1-xMIIIx(MoO4)3 (MIII = Cr, Fe) and Li3-xAl1-xMII2x(MoO4)3 (MII = Co, Ni, Cu) and interpreted the results in terms of average crystal field strengths experienced by MIII/MII ions at multiple coordination geometries. We have also identified the role of metal-to-metal charge transfer (MMCT) from the partially filled transition metal 3d orbitals to the empty Mo – 4d orbitals in the resulting colours of these oxides. B The ABO3 perovskite structure consists of a three dimensional framework of corner shared BO6 octahedra in which large A cation occupies dodecahedral site, surrounded by twelve oxide ions. The ideal cubic structure occurs when the Goldschmidt’s tolerance factor, t = (rA + rO)/{√2(rB + rO)}, adopts a value of unity and the A–O and B–O bond distances are perfectly matched. The BO6 octahedra tilt and bend the B – O – B bridges co-operatively to adjust for the non-ideal size of A cations, resulting deviation from ideal cubic structure to lower symmetries. Ordering of cations at the A and B sites of perovskite structure is an important phenomenon. Ordering of site cations in double (A2BB'O6) and multiple (A3BB'2O9) perovskites give rise to newer and interesting materials properties. Depending upon the constituent transition metals and ordering, double perovskite oxides exhibit a variety of magnetic behaviour such as ferromagnetism, ferrimagnetism, antiferromagnetism, spin-glass magnetism and so on. We also have coupled magnetic properties such as magnetoresistance (Sr2FeMoO6), magnetodielectric (La2NiMnO6) and magnetooptic (Sr2CrWO6) behaviour. Here we have investigated new magnetically frustrated double perovskite oxides of the formula Ln3B2RuO9(B = Co, Ni and Ln = La, Nd). The Chapter 4.1 describes Ln3B2RuO9 (B = Co, Ni and Ln = La, Nd) oxides (prepared by a solid state metathesis route) which adopt a monoclinic (P21/n) A2BB'O6 double perovskite structure, wherein the two independent octahedral 2c and 2d sites are occupied by B2+ and (B2+1/3Ru5+2/3) atoms, respectively. Temperature dependence of the molar magnetic susceptibility plots obtained under zero field cooled (ZFC) condition exhibit maxima in the temperature range 25–35K, suggesting an antiferromagnetic interaction in all these oxides. Ln3B2RuO9 oxides show spin-glass behavior and no long-range magnetic order is found down to 2 K. The results reveal the importance of competing nearest neighbour (NN), next nearest neighbor (NNN) and third nearest neighbour (third NN) interactions between the magnetic Ni2+/Co2+ and Ru5+ atoms in the partially ordered double perovskite structure that conspire to thwart the expected ferromagnetic order in these materials.

La synthèse d’images réalistes repose sur des modèles physiques décrivant les interactions entre la lumière et les matériaux attachés aux objets dans une scène tridimensionnelle. Ces modèles mathématiques sont complexes et, dans le cas général, n’admettent pas de solution analytique. Pour cette raison, l’utilisation de méthodes numériques robustes et efficaces est nécessaire. Les méthodes de Monte Carlo ou techniques alternatives comme l’utilisation de développement par fonction de base sont appropriées pour résoudre ce type de problème. Dans cette thèse par articles, nous présentons deux nouvelles techniques permettant l’in- tégration numérique efficace de matériaux complexes. En premier lieu, nous introduisons une nouvelle méthode permettant d’intégrer simultanément plusieurs dimensions définies dans le domaine angulaire et spatiale. Avoir une technique efficace est essentiel pour intégrer des matériaux avec des normales variant rapidement sous différentes conditions d’éclairage. Notre technique utilise une nouvelle formulation basée sur un histogramme sphérique définie de façon directionnelle et spatial. Ce dernier nous permet d’utiliser des harmoniques sphé- riques pour intégrer les différentes dimensions rapidement, réduisant le temps de calcul d’un facteur approximatif de 30× par rapport aux méthodes de l’état de l’art. Dans notre second travail, nous introduisons une nouvelle stratégie d’échantillonnage pour estimer le transport de lumière à l’intérieur de matériaux multicouches. En identifiant les meilleures stratégies d’échantillonnage, nous proposons une technique efficace et non biaisée pour construire des chemins de lumière à l’intérieur de ce type de matériau. Notre nouvelle approche permet d’obtenir un estimateur de Monte Carlo efficace et de faible variance dans des matériaux contenant un nombre arbitraire de couches. / Realistic computer generated images and simulations require physically-based models to properly capture and reproduce light-material interactions. The underlying mathematical formulations are complex and mandate the use of efficient numerical methods, since analytic solutions are not available. Monte Carlo integration is one such commonly used numerical method, although, alternative approaches leveraging, e.g., basis expansions, may be suitable to solve these challenging problems. In this thesis by articles, we present two works where we efficiently devise numerical integration strategies for the rendering of complex materials. First, we propose a method to compute a spatial-angular multi-dimensional integration problem present when rendering materials with high-frequency normal variation under large, angularly varying illumination. By computing and manipulating a novel spherical histogram data representation, we are able to use spherical harmonics to efficiently solve the integral, outperforming the state-of-the-art by a factor of roughly 30×. Our second work describes a high-performance Monte Carlo integration strategy for rendering layered materials. By identifying the best path sampling strategies in the micro-scale light transport context, we are able to tailor an unbiased and efficient path construction method to evaluate high throughput, low variance paths through an arbitrary number of layers.

Le complexe mafique–ultramafique lité Yacouba est intrusif au sein des granulites gneissiques du domaine archéen de Man (3,6-2,78 Ga) dans la région de Biankouma-Sipilou (ouest de la Côte d'Ivoire). Dans le secteur de Samapleu, il est composé de trois entités ; dépôt principal de Samapleu (SM), l’Extension 1 de Samapleu (E1) et l’occurrence de Yorodougou (Yo). Il comprend des horizons de webstérites, péridotites, chromitites, norites, gabbro-norites. Ces horizons (épaisseur cumulée de 80 à 200 m) sont inclinés de 70 à 80° vers le SE ; présentent une zonation concentrique, qui sont autant de caractéristiques d’un dyke ; un enracinement à plus de 600 m à partir de la surface avec une jonction des intrusions (SM, E1) plus en profondeur. Les contacts avec l’encaissant gneissique (localement site E1) sont marqués par une zone hybride (condition P = 7,5±1Kbar et T = 850°C ± 100°C) interprétées comme le résultat d'un métamorphisme de contact lors de la mise en place de l’intrusion en base de croûte à environ 22 km de profondeur. Les gneiss et granulites du socle, tout comme les faciès de la zone hybride, préservent des âges archéens (~2,78 Ga, U-Pb sur zircon). Des cristaux de rutile observés dans la zone hybride révèlent un âge U-Pb de 2,09 Ga interprété comme l'âge du métamorphisme de contact et donc de la mise en place de l'intrusion.La minéralisation en Ni-Cu (essentiellement disséminée avec des veines sulfurées subverticales semi-massives à massives) est composée de pentlandite, chalcopyrite, pyrrhotite, rarement pyrite. La texture des sulfures varie de matricielle, en filets, en gouttelettes, ou brèchique. Les réserves estimées des dépôts de Samapleu (SM et E1) font plus de 40 millions de tonnes à une teneur moyenne de 0,25% Ni et 0,22% Cu dans la partie supérieure des intrusions (Sama Nickel-CI, Août 2013). Des MGP riches en palladium (Pd) sont associés aux sulfures et plusieurs bandelettes de chromite sont également présentes. Ces observations suggèrent un liquide sulfuré immiscible formé à partir du liquide silicaté initial consécutivement à la saturation en soufre du système. Ces sulfures d’origine essentiellement mantellique ont été probablement formés par injection de plusieurs magmas. Cependant une partie de ces sulfures aurait pu se former par l’assimilation des roches granulitiques encaissantes.La composition du liquide parent révèle une composition de basalte à forte teneur en MgO et faible teneur en Ti et suggère que les intrusions de Samapleu se sont formées par fusion du manteau supérieur sous l’influence d'un panache mantellique. Ainsi, lors de leurs remontées, le magma a assimilé les roches granulites encaissantes environnantes. / The Yacouba layered complex intrudes the archean (3.6-2.78 Ga) Man field in the Biankouma-Sipilou area, western Ivory Coast. In Samapleu area, the complex is composed of three entities; Samapleu Main (SM); Samapleu Extension 1 (E1) and Yorodougou (Yo). It includes websterites, peridotites, chromitites, norites, gabbro-norites horizons. These horizons (total thickness of 80 to 200 m) inclined at 70-80° to the SE; arranged symmetrically with mafic layers at the center and ultramafic layers at both margins, are features of a dyke ; show a root more than 600 m from the surface with a junction intrusion (SM, E1) in more depth.At the E1 site, contacts of intrusions with the country rock gneiss are characterized by a hybrid zone (condition P = 7.5±1Kbar and T = 850°C ± 100°C) attributed to contact metamorphism during intrusion of the complex in the lower crust at a depth of about 22 km. Zircons in country rock gneisses and granulites, as well as in the hybrid facies, yield archean ages of ~ 2.78 Ga. Rutiles in the hybrid zone give a U-Pb age of 2.09 Ga, which is interpreted as the age of contact metamorphism and emplacement of the intrusion.The Ni-Cu mineralization (disseminated mainly with subvertical and semi-massive to massive sulfide veins) is composed of pentlandite, chalcopyrite, pyrrhotite and rare pyrite. The SM and E1 sites contain Ni and Cu sulfide deposit with reserves estimated as more than 40 million tons grading 0.25% Ni and 0.22% Cu in the upper portion (Sama Nickel-CI, August 2013). The sulfide textures range from matrix ore, net-textured, droplets or breccia textures. Zones enriched in PGM, particularly Pd, are associated with the sulfides and several chromite bands are also present. These observations suggest that an immiscible sulfide liquid formed from a parental silicate liquid and percolated through the crystal pile. These sulfides mainly mantle origin were probably formed by injecting several magmas. However few of these sulfides may have formed by the assimilation of country rocks.The parental melt composition has a basalt rich MgO and low Ti and suggest Samapleu intrusions were formed by melting of the upper mantle under the influence of a mantle plume. Thus, during its ascent, magma has assimilated the granulites country rocks.

Desde comienzos del siglo XXI, los sistemas de radiodifusión terrestre han sido culpados de un uso ineficiente del espectro asignado. Para aumentar la eficiencia espectral, los organismos de estandarización de TV digital comenzaron a desarrollar la evolución técnica de los sistemas de TDT de primera generación. Entre otros, uno de los objetivos principales de los sistemas de TDT de próxima generación (DVB-T2 y ATSC 3.0) es proporcionar simultáneamente servicios de TV a dispositivos móviles y fijos. El principal inconveniente de esta entrega simultánea son los diferentes requisitos de cada condición de recepción. Para abordar estas limitaciones, se han considerado diferentes técnicas de multiplexación. Mientras que DVB-T2 acomete la entrega simultánea de los dos servicios mediante TDM, ATSC 3.0 adoptó la Multiplexación por División en Capas (LDM). LDM puede superar a TDM y a FDM al aprovechar la relación de Protección de Error Desigual (UEP), ya que ambos servicios, llamados capas, utilizan todos los recursos de frecuencia y tiempo con diferentes niveles de potencia. En el lado del receptor, se distinguen dos implementaciones, de acuerdo con la capa a decodificar. Los receptores móviles solo están destinados a obtener la capa superior, conocida como Core Layer (CL). Para no aumentar su complejidad en comparación con los receptores de capa única, la capa inferior, conocida como Enhanced Layer (EL), es tratada como un ruido adicional en la decodificación. Los receptores fijos aumentan su complejidad, ya que deben realizar un proceso de Cancelación de Interferencia (SIC) sobre la CL para obtener la EL. Para limitar la complejidad adicional de los receptores fijos, las capas de LDM en ATSC 3.0 están configuradas con diferentes capacidades de corrección, pero comparten el resto de bloques de la capa física, incluido el TIL, el PP, el tamaño de FFT, y el GI. Esta disertación investiga tecnologías avanzadas para optimizar el rendimiento de LDM. Primero se propone una optimización del proceso de demapeo para las dos capas de LDM. El algoritmo propuesto logra un aumento de capacidad, al tener en cuenta la forma de la EL en el proceso de demapeo de la CL. Sin embargo, el número de distancias Euclidianas a computar puede aumentar significativamente, conduciendo no solo a receptores fijos más complejos, sino también a receptores móviles más complejos. A continuación, se determina la configuración de piloto ATSC 3.0 más adecuada para LDM. Teniendo en cuenta que las dos capas comparten el mismo PP, surge una contrapartida entre la densidad de pilotos (CL) y la redundancia sobre los datos (EL). A partir de los resultados de rendimiento, se recomienda el uso de un PP no muy denso, ya que ya han sido diseñados para hacer frente a ecos largos y altas velocidades. La amplitud piloto óptima depende del estimador de canal en los receptores (ej., se recomienda la amplitud mínima para una implementación Wiener, mientras que la máxima para una implementación FFT). También se investiga la potencial transmisión conjunta de LDM con tres tecnologías avanzadas adoptadas en ATSC 3.0: las tecnologías de agregación MultiRF, los esquemas de MISO distribuido y los de MIMO colocalizado. Se estudian los potenciales casos de uso, los aspectos de implementación del transmisor y el receptor, y las ganancias de rendimiento de las configuraciones conjuntas para las dos capas de LDM. Las restricciones adicionales de combinar LDM con las tecnologías avanzadas se consideran admisibles, ya que las mayores demandas ya están contempladas en ATSC 3.0 (ej., una segunda cadena de recepción). Se obtienen ganancias significativas en condiciones de recepción peatonal gracias a la diversidad en frecuencia proporcionada por las tecnologías MultiRF. La conjunción de LDM con esquemas de MISO proporciona ganancias de rendimiento significativas en redes SFN para la capa fija con el esquema de Alamouti. / Since the beginning of the 21st century, terrestrial broadcasting systems have been blamed of an inefficient use of the allocated spectrum. To increase the spectral efficiency, digital television Standards Developing Organizations settled to develop the technical evolution of the first-generation DTT systems. Among others, a primary goal of next-generation DTT systems (DVB-T2 and ATSC 3.0) is to simultaneously provide TV services to mobile and fixed devices. The major drawback of this simultaneous delivery is the different requirement of each reception condition. To address these constraints different multiplexing techniques have been considered. While DVB-T2 fulfilled the simultaneous delivery of the two services by TDM, ATSC 3.0 adopted the LDM technology. LDM can outperform TDM and FDM by taking advantage of the UEP ratio, as both services, namely layers, utilize all the frequency and time resources with different power levels. At receiver side, two implementations are distinguished, according to the intended layer. Mobile receivers are only intended to obtain the upper layer, known as CL. In order not to increase their complexity compared to single layer receivers, the lower layer, known as EL is treated as an additional noise on the CL decoding. Fixed receivers, increase their complexity, as they should performed a SIC process on the CL for getting the EL. To limit the additional complexity of fixed receivers, the LDM layers in ATSC 3.0 are configured with different error correction capabilities, but share the rest of physical layer parameters, including the TIL, the PP, the FFT size, and the GI. This dissertation investigates advanced technologies to optimize the LDM performance. A demapping optimization for the two LDM layers is first proposed. A capacity increase is achieved by the proposed algorithm, which takes into account the underlying layer shape in the demapping process. Nevertheless, the number of Euclidean distances to be computed can be significantly increased, contributing to not only more complex fixed receivers, but also more complex mobile receivers. Next, the most suitable ATSC 3.0 pilot configuration for LDM is determined. Considering the two layers share the same PP a trade-off between pilot density (CL) and data overhead (EL) arises. From the performance results, it is recommended the use of a not very dense PP, as they have been already designed to cope with long echoes and high speeds. The optimum pilot amplitude depends on the channel estimator at receivers (e.g. the minimum amplitude is recommended for a Wiener implementation, while the maximum for a FFT implementation). The potential combination of LDM with three advanced technologies that have been adopted in ATSC 3.0 is also investigated: MultiRF technologies, distributed MISO schemes, and co-located MIMO schemes. The potential use cases, the transmitter and receiver implementations, and the performance gains of the joint configurations are studied for the two LDM layers. The additional constraints of combining LDM with the advanced technologies is considered admissible, as the greatest demands (e.g. a second receiving chain) are already contemplated in ATSC 3.0. Significant gains are found for the mobile layer at pedestrian reception conditions thanks to the frequency diversity provided by MultiRF technologies. The conjunction of LDM with distributed MISO schemes provides significant performance gains on SFNs for the fixed layer with Alamouti scheme. Last, considering the complexity in the mobile receivers and the CL performance, the recommended joint configuration is MISO in the CL and MIMO in the EL. / Des de començaments del segle XXI, els sistemes de radiodifusió terrestre han sigut culpats d'un ús ineficient de l'espectre assignat. Per a augmentar l'eficiència espectral, els organismes d'estandardització de TV digital van començar a desenvolupar l'evolució tècnica dels sistemes de TDT de primera generació. Entre altres, un dels objectius principals dels sistemes de TDT de pròxima generació (DVB-T2 i el ATSC 3.0) és proporcionar simultàniament serveis de TV a dispositius mòbils i fixos. El principal inconvenient d'aquest lliurament simultani són els diferents requisits de cada condició de recepció. Per a abordar aquestes limitacions, s'han considerat diferents tècniques de multiplexació. Mentre que DVB-T2 escomet el lliurament simultani dels dos serveis mitjançant TDM, ATSC 3.0 va adoptar la Multiplexació per Divisió en Capes (LDM). LDM pot superar a TDM i a FDM en aprofitar la relació de Protecció d'Error Desigual (UEP), ja que tots dos serveis, cridats capes, utilitzen tots els recursos de freqüència i temps amb diferents nivells de potència. En el costat del receptor, es distingeixen dues implementacions, d'acord amb la capa a decodificar. Els receptors mòbils solament estan destinats a obtenir la capa superior, coneguda com Core Layer (CL). Per a no augmentar la seua complexitat en comparació amb els receptors de capa única, la capa inferior, coneguda com Enhanced Layer (EL), és tractada com un soroll addicional en la decodificació. Els receptors fixos augmenten la seua complexitat, ja que han de realitzar un procés de Cancel·lació d'Interferència (SIC) sobre la CL per a obtenir l'EL. Per a limitar la complexitat addicional dels receptors fixos, les capes de LDM en ATSC 3.0 estan configurades amb diferents capacitats de correcció, però comparteixen la resta de blocs de la capa física, inclòs el TIL, el PP, la grandària de FFT i el GI. Aquesta dissertació investiga tecnologies avançades per a optimitzar el rendiment de LDM. Primer es proposa una optimització del procés de demapeo per a les dues capes de LDM. L'algoritme proposat aconsegueix un augment de capacitat, en tenir en compte la forma de l'EL en el procés de demapeo de la CL. No obstant açò, el nombre de distàncies Euclidianes a computar pot augmentar significativament, conduint NO sols a receptors fixos més complexos, sinó també a receptors mòbils més complexos. A continuació, es determina la configuració de pilot ATSC 3.0 més adequada per a LDM. Tenint en compte que les dues capes comparteixen el mateix PP, es produeix una contrapartida entre la densitat de pilots (CL) i la redundància sobre les dades (EL). A partir dels resultats de rendiment, es recomana l'ús d'un PP no gaire dens, ja que ja han sigut dissenyats per a fer front a ecos llargs i altes velocitats. L'amplitud pilot òptima depèn de l'estimador de canal en els receptors (ex., es recomana l'amplitud mínima per a una implementació Wiener, mentre que la màxima per a una implementació FFT). També s'investiga la potencial transmissió conjunta de LDM amb tres tecnologies avançades adoptades en ATSC 3.0: les tecnologies d'agregació de MultiRF, els esquemes de MISO distribuït i els de MIMO colocalitzat. S'estudien els potencials casos d'ús, els principals aspectes d'implementació del transmissor i el receptor, i els guanys de rendiment de les configuracions conjuntes per a les dues capes de LDM. Les restriccions addicionals de combinar LDM amb les tecnologies avançades es consideren admissibles, ja que les majors demandes ja estan contemplades en ATSC 3.0 (ex., una segona cadena de recepció). S'obtenen guanys significatius per a la capa mòbil en condicions de recepció per als vianants gràcies a la diversitat en freqüència proporcionada per les tecnologies MultiRF. La conjunció de LDM amb esquemes MISO distribuïts proporciona guanys de rendiment significatius en xarxes SFN per a la capa fixa amb l'esquema d'Alamouti. / Garro Crevillén, E. (2018). Advanced Layered Divsion Multiplexing Technologies for Next-Gen Broadcast [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/105559 / TESIS