Artifacts made of durable materials, such as stone, can provide valuable clues to reconstruct the past. Marble sourcing, in particular,provides information about contact, trade, and other activities in the greater Mediterranean area. The Worcester Art Museum of Massachusetts (WAM) initiated a provenance study by requesting that an analysis of several marble artifacts occur at the University of South Florida's Archaeological Science Laboratory. The 55 marble samples used in this study are from the Worcester Art Museum's collection of Antioch mosaics. Positive results might reveal: 1) preferred sources of tesserae, 2) information about trade of specialized stone, 3) changes in preferred sources during different chronological periods, and 4) workshop preferences. The requested analysis had two objectives. First, once the provenance of the materials is determined, then the results could reveal meaning behind the images contained within the mosaic floor. Second, the results could reveal new trade routes in the Mediterranean. The first step in this analysis was X-ray diffraction (XRD),which differentiates dolomite and calcite marbles. The second step used stable isotope ratio analysis (SIRA), which measures carbon-13 and oxygen-18 isotopic ratios. These two steps have helped to identify Mediterranean marble sources in previous studies. Most of the ancient Mediterranean marble sources have been identified. They have different isotopic values and other characteristics that allow for differentiation. Only one source of dolomite marble exists, which is located in the eastern Mediterranean. It has been identified through XRD in previous studies. Many of the calcite marble sources have different carbon and oxygen isotopic values, which were provided from the SIRA. Those marble artifacts with overlapping carbon and oxygen values can be further analyzed using archaeological, historical, and other information and by using other scientific techniques including cathodoluminescence, electron paramagnetic resonance, and strontium isotope analysis. This thesis discusses the methods used to prepare the samples and analysis conduction; it also discusses the results of the analyses, and presents interpretations regarding the provenance and trade of the marble used for mosaics at Antioch. The results of the SIRA and XRD analysis showed that the materials used for mosaic tesserae come from a variety of sources. Although no definitive matches were found, the results provide the basis for the collection of a colored marble database of sources and artifacts.

Η υδροχλωρική δονεπεζίλη (Donepezil.HCl, DPZ) είναι ένα φάρμακο που λαμβάνεται για τη θεραπεία της νόσου Altzheimer. Δρα ως ανασολέας της ακετυλοχοληστερινάσης, ενός ενζύμου υπεύθυνου για την καταστροφή του νευροδιαβιβαστή ακετυλοχολίνη, αυξάνοντας το ποσό της ακετυλοχολίνης στον εγκέφαλο. Παρουσιάζει διάφορες κρυσταλλικές μορφές, συμπεριλαμβανομένων δύο ένυδρων, καθώς και μια άμορφη φάση. Τα δισκία Υδροχλωρικής Δονεπεζίλης λαμβάνονται από το στόμα και μπορεί να αποθηκευθούν για κάποιο χρονικό διάστημα πριν χρησιμοποιηθούν. Τα δισκία DPZ ισχύος 10 mg περιέχουν 3.6 % API, ενώ στις περιπτώσεις όπου λαμβάνει χώρα πολυμορφική μετατροπή, η επιμέρους περιεκτικότητα κάθε πολυμόρφου είναι ακόμα μικρότερη. Η ταυτοποίηση και ποσοτική ανάλυση των πολυμόρφων ή ένυδρων μορφών είναι δυνατή μόνο με τη χρήση περίθλασης ακτίνων Χ και δονητικών φασματοσκοπικών τεχνικών. Λόγω του μικρού ποσοστού της δραστικής ουσίας στα δισκία και της πιθανής παρουσίας περισσοτέρων του ενός πολυμόρφου αλλά και του μεγάλου σχετικά ορίου ανίχνευσης αυτών των τεχνικών η ταυτοποίηση και ποσοτική ανάλυση είναι μια αναλυτική πρόκληση. Στην παρούσα εργασία έγινε προσπάθεια ταυτοποίησης των κρυσταλλικών μορφών του DPZ σε δισκία και έλεγχος της σταθερότητάς τους μετά από διάφορες διαδικασίες παρασκευής των δισκίων, καθώς και μετά από αποθήκευση σε διάφορες συνθήκες υγρασίας και θερμοκρασίας, χρησιμοποιώντας τις πειραματικές τεχνικές XRD, FT-IR και FT-Raman. Παρατηρήθηκε ότι η προέλευση του API, οι συνθήκες αποθήκευσης και κυρίως η μέθοδος παρασκευής των δισκίων επηρεάζουν τη σταθερότητα των φαρμακευτικών σκευασμάτων. Με στόχο τη διερεύνηση της δυνατότητας ανάπτυξης ποσοτικών αναλυτικών μεθόδων προσδιορισμού των πολυμόρφων Ι και ΙΙΙ του DPZ σε δισκία, οι παραπάνω τεχνικές χρησιμοποιήθηκαν για τον υπολογισμό των ορίων ανίχνευσης των δύο πολυμόρφων (0.35% κ.β. για το πολύμορφο Ι και 0.44 % κ.β. για το πολύμορφο ΙΙΙ με την τεχνική Raman, 0.95% κ.β. για το πολύμορφο Ι και 1.3 % κ.β. για το πολύμορφο ΙΙΙ με την τεχνική XRD, 1.2% κ.β. για τη μορφή Ι και 1.0 % κ.β. για τη μορφή ΙΙΙ με την τεχνική IR, όπως προέκυψαν μετά από στατιστική επεξεργασία των πειραματικών δεδομένων των διαφόρων τεχνικών), καθώς και για τον ποσοτικό τους προσδιορισμό. Η τεχνική Raman φαίνεται να μπορεί χρησιμοποιηθεί για ποσοτική ανάλυση των πολυμόρφων Ι και ΙΙΙ του DPZ σε δισκία, ενώ επιπλέον η ποσοτική μέθοδος που παρουσιάσθηκε εδώ είναι απλή και μη καταστροφική για τα δείγματα. Η μέθοδος XRD μπορεί πιθανόν να χρησιμοποιηθεί για την ποσοτική ανάλυση δισκίων DPZ, με μεγαλύτερο όμως σφάλμα σε σύγκριση με την τεχνική Raman, ενώ η μέθοδος FT-IR ATR, παρέχει τα λιγότερο καλά ποσοτικά αποτελέσματα, ακόμα και στην περίπτωση που το δισκίο περιέχει αποκλειστικά το ένα από τα δύο πολύμορφα. Τέλος, με στόχο την ερμηνεία των φασμάτων δόνησης που καταγράφησαν στην παρούσα εργασία, υπολογίστηκαν η σταθερή δομή του μορίου της Δονεπεζίλης και της ένυδρης Δονεπεζίλης (με ένα μόριο νερού ανά μόριο Δονεπεζίλης) και τα φάσματα δόνησης (IR και Raman) με τις μεθόδους Hartree-Fock ab-initio και DFT (Density Functional Theory) και χρήση του υπολογιστικού πακέτου Gaussian09. / Donepezil hydrochloride (DPZ) is a medication used to treat Altzheimer’s disease. It acts as an inhibitor of acetylcholisterinase, an enzyme responsible for the destruction of the neurotransmitter acetylcholine, thus increasing the level of acetylcholine in the brain. As most of the pharmaceutical solids, DPZ exhibits polymorphism. Donepezil hydrochloride has different crystalline forms, including two hydrates, as well as an amorphous phase. DPZ is available for oral administration in tablets which can be stored for some time before use. In the present study, an effort was made to identify the crystal form of DPZ in tablets, as well as to test its stability against time, temperature and humidity, after various manufacturing processes, using XRD, FT-IR and FT-Raman techniques. The data showed that the origin of the API, the storing conditions and mainly the manufacturing process of the tablets affect the stability of the API. Quantitative determination of polymorphs I and III of DPZ in tablets was also attempted using the above experimental methods. Calibration models were constructed and applied in DPZ tablets. The detection limits of polymorphs I and III of DPZ for each technique, derived after statistical treatment of the experimental data, were calculated. Raman spectroscopy exhibited the lower detection limit (0.35 weigh % for polymorph Ι and 0.44 % weigh % for polymorph ΙΙΙ) compared with XRD (0.95% weigh % for polymorph Ι and 1.3 % weigh % for polymorph ΙΙΙ) and IR spectroscopy (1.2% weigh % for polymorph Ι and 1.0 % weigh % for polymorph ΙΙΙ). The data suggest that Raman spectroscopy could be applied to quantify polymorphs I and III in DPZ tablets; moreover, the Raman quantitative method presented in this work is simple and non-destructive for the tablets. The application of the X ray diffraction method for the quantitative analysis of polymorphs I and III in tablets yielded larger errors compared with Raman spectroscopy, while the FT-IR ATR technique yielded poor quantitative results, even in the case that only one polymorph was present in DPZ tablets. Finaly, in order to facilitate the assignment of the vibrational spectra recorded in this study, the optimized structure and the vibrational spectra (IR and Raman) of Donepezil and Donepezil hydrate (Donepezil:H20 = 1:1) molecules were calculated at the Hartree-Fock and DFT (Density Functional Theory) level of theory using the Gaussian 09 program package. The weigh % of the API in the tablets containing 10 mg of DPZ is 3.6 %. In cases where two or more polymorphs are present, the weigh % of each polymorphic form is lower. The difficulty in the identification and quantification of the crystal phase of DPZ is stemming from the small percentage of the API in the tablets, the considerable overlapping of DPZ XRPD patterns and IR and Raman spectra of the polymorphs and the excipients and the availability of various polymorphs.

>Magister Scientiae - MSc / Organic-inorganic lead-based perovskite has exhibited great performance in the past few years. However, the lead (Pb) embedded in those compounds is a significant drawback to further progress, due to its environmental toxicity. As an alternative, tin (Sn) based-perovskites have demonstrated promising results in terms of electrical and optical properties for photovoltaic devices, but the oxidation of tin ion- from stannous ion (Sn2+) to stannic ion (Sn4+) presents a problem in terms of performance and stability when exposed to ambient conditions. A more feasible approach may be in a Pb-Sn binary metal perovskite in pursuit of efficient, stable perovskite solar cells (PSCs) with reduced Pb-content, as compared to pure Pb- or Sn-based PSCs. Here, we report on the deposition of a Pb-Sn binary perovskite by sequential chemical vapor deposition.

Submitted by Emanuel Varela Cardoso (emanuel.varela@ufcg.edu.br) on 2018-06-26T19:38:51Z No. of bitstreams: 1 POLYANA TARCIANA ARAÚJO DOS SANTOS – TESE (UAEMa) 2015.pdf: 2974694 bytes, checksum: 08e52baa2c42ce5e7b0e35cbf00934bd (MD5) / Made available in DSpace on 2018-06-26T19:38:51Z (GMT). No. of bitstreams: 1 POLYANA TARCIANA ARAÚJO DOS SANTOS – TESE (UAEMa) 2015.pdf: 2974694 bytes, checksum: 08e52baa2c42ce5e7b0e35cbf00934bd (MD5) Previous issue date: 2015-01-29 / CNPq / Neste trabalho de pesquisa foi obtido um material híbrido a base de nanoferritas Ni0,5Zn0,5Fe2O4 e CoFe2O4 modificada a superfície com agente silano e funcionalizadas com quitosana visando seu uso como biossensores. Para este fim, as nanoferritas foram sintetizadas por reação de combustão e silanizadas com o 3-aminopropiltrimetoxissilano. A funcionalização foi realizada pelo método de evaporação do solvente usando o biopolímero quitosana. Todas as amostras foram caracterizadas por difração de raios X, espectrometria de infravermelho por transformada de Fourier, espectroscopia por energia dispersiva de raios X, análise termogravimétrica, microscopia eletrônica de varredura, microscopia eletrônica de transmissão, teste de sedimentação e separação magnética, medidas magnéticas e análise in vitro por citotoxidade. As amostras como sintetizadas apresentaram a formação da fase única do espinélio em estudo com característica nanométrica e após a formação do híbrido a estrutura do material foi mantida. Nos espectros de infravermelho observaram-se bandas de absorção características das nanoferritas e bandas referentes à presença do agente silano e da quitosana. Por meio das micrografias observou-se a formação de aglomerados de aspecto frágil, e após silanização e funcionalização observou-se uma morfologia com aglomerados de aspecto mais rígido constituídos de nanopartículas fortemente ligadas. A análise termogravimétrica mostrou que as nanoferritas apresentaram baixa perda de massa e que após formação do híbrido houve um aumento da perda de massa comprovando assim, a presença do agente silano e da quitosana. Quanto ao comportamento magnético, ambas as nanoferritas apresentaram elevada magnetização de saturação típica de materiais ferrimagnéticos, este comportamento foi mantido após formação do híbrido sendo adequado para aplicações biotecnológicas. A viabilidade celular das nanoferritas mostrou característica citotóxica para a ferrita Ni0,5Zn0,5Fe2O4 e não citotóxica para a ferrita CoFe2O4, a formação do híbrido favoreceu aumento da viabilidade celular em ambas as nanoferritas. Os materiais híbridos obtidos são promissores para o uso na nanobiotecnologia como biossensores e/ou em tratamento como diagnóstico clinico. / In this research was obtained a hybrid material nanoferrit es base Ni0,5Zn0,5Fe2O4 and CoFe2O4 modified the surface with silane agent and functionalized chitosan aiming their use as biosensors. To this end, nanoferritas were synthesized by combustion and silanized with 3-aminopropyltrimethoxysilane. The functionalization was carried out by the solvent evaporation method using the biopolymer chitosan. All samples were characterized by X-ray diffraction, infrared spectroscopy by Fourier transform spectroscopy energy dispersive X-ray, thermal analysis, scanning electron microscopy, transmission electron microscopy, sedimentation test and magnetic separation, magnetic measurements and Analysis by in vitro cytotoxicity. The samples showed synthesized as the formation of spinel single phase with nanometer feature under study and after the formation of the hybrid structure of the material has been maintained. In the infrared spectra there were absorption bands characteristic of nanoferritas and bands related to the presence of the silane agent and chitosan. Through micrographs showed the formation of agglomerates frail and after silanization and functionalization was observed with a morphology more rigid aspect of tightly bound agglomerates of nanoparticles. Thermogravimetric analysis showed that the nanoferritas showed low weight loss and that after hybrid formation was increased mass loss thereby proving the presence of the silane agent and chitosan. As for the magnetic behavior, both nanoferritas had high magnetization typical saturation ferrimagnetic materials, this behavior continued after the hybrid formation is suitable for biotechnological applications. Cell viability nanoferritas showed characteristic for cytotoxic and non-cytotoxic ferrite Ni0,5Zn0,5Fe2O4 to CoFe2O4 ferrite, the formation of hybrid favored increased cell viability in both nanoferritas. The obtained hybrid materials are promising for use in nanobiotechnology as biosensors and / or treatment and clinical diagnosis.

Submitted by ANA LAURA CURCIO null (analaura.curcio@bol.com.br) on 2016-04-27T20:10:28Z No. of bitstreams: 1 merged_document.pdf: 1672370 bytes, checksum: fd59b862449a04ac385f3661da6430f3 (MD5) / Approved for entry into archive by Felipe Augusto Arakaki (arakaki@reitoria.unesp.br) on 2016-04-29T17:42:15Z (GMT) No. of bitstreams: 1 curcio_al_me_rcla.pdf: 1672370 bytes, checksum: fd59b862449a04ac385f3661da6430f3 (MD5) / Made available in DSpace on 2016-04-29T17:42:15Z (GMT). No. of bitstreams: 1 curcio_al_me_rcla.pdf: 1672370 bytes, checksum: fd59b862449a04ac385f3661da6430f3 (MD5) Previous issue date: 2016-02-29 / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Nanocristais tem sido extensivamente investigados nos últimos anos devido à sua ampla gama de aplicações em vários dispositivos tais como sensores, células solares, lasers, fotocatalisadores, fotodetectores, detectores de infravermelhos, diodos emissores de luz, materiais eletroluminescentes e outros materiais emissores de luz. Semicondutores nanocristalinos apresentam propriedades eletrônicas intermediárias entre aqueles de estrutura molecular e sólidos macrocristalinos, proporcionando uma ampla gama de aplicações. Entre estes materiais, o sulfeto de zinco (ZnS) puro ou dopado tem recebido notável atenção por causa de suas propriedades estruturais ópticas, versatilidade e potencial para várias aplicações tecnológicas. O ZnS é um típico semicondutor II-VI, com um gap direto de 3,6 eV à temperatura ambiente e aproximadamente 40 meV de energia de gap, sendo um bom material luminescente utilizado em telas, sensores e lasers. Como material de gap largo, o ZnS pode facilmente hospedar diferentes metais de transição como centros luminescentes. Entre estes íons de metais de transição para estruturas dopadas, os íons Cu2+e Mn2+ são atraentes pelas emissões de luz características e por apresentarem propriedades eficientes para aplicações como luminóforos. A inserção desses íons na estrutura do ZnS proporcionam defeitos que resultam em emissão no verde para os íons Cu2+e emissão no laranja para os íons Mn2+. Neste estudo, as amostras de ZnS pura e dopadas com Cu2+ e Mn2+ foram preparados pelo método solvotermal, que demonstra ser um processo eficaz para preparar nanopartículas. Uma vez preparadas, as estruturas das amostras nanoestruturadas foram caracterizadas e correlacionada s com propriedades fotoluminescentes. Os resultados de difração de raios X mostram que as amostras de ZnS foram cristalizadas completamente sem a presença de fases secundárias e os difratogramas correspondem à estrutura blenda cúbica de zinco com grupo espacial F-43m. Os espectros de XANES (X-ray Absorption Near Edge Structure) teóricos e experimentais na borda K do Zn indicam que a incorporação de átomos de Mn na matriz ZnS causam a formação de vacâncias de Zn e S, a qual é confirmada por ajustes de espectros EXAFS (Extended X-ray Absorption Fine Structure). Estas vacâncias estão relacionadas com um desvio para o vermelho observado no pico do espectro de fotoluminescência devido a adição de Mn na estrutura do ZnS. Para o ZnS puro, o pico é centrado em ~ 504 nm, relativo as vacâncias de S na amostra nanoestruturada. À medida que se aumenta a porcentagem de Mn na matriz ZnS, uma emissão no amarelo-laranja centrada em ~ 590 nm pode ser observada, associada com a transição 4T1-6A1 no interior de níveis 3d de Mn2+. A adição de íons Cu2+ ao ZnS resulta em um alargamento no pico do espectro de fotoluminescência decorrente de emissão no azul-verde, que está relacionada a recombinação de elétrons de níveis de defeitos mais profundos dos estados t2 do Cu próximos da banda de valência. / Nanocrystals has been extensively investigated in recent years due to its wide range of applications in various devices light emitting materials such as sensors, solar cells, lasers, photocatalysts, photodetectors, IR detectors, light emitting diodes and others. Nanocrystalline Semiconductors have electronic properties between those intermediate molecular macrocristalinos and solid structure, providing a wide range of applications. Among these materials, zinc sulfide (ZnS) pure or doped has received considerable attention because of its optical structural properties, versatility and potential for several technological applications. The ZnS is a typical II-VI semiconductor with a direct band gap of 3.6 eV at room temperature and about 40 meV in energy gap, and a good luminescent material for constrution of displays, lasers and sensors. As wide band gap material, ZnS can easily host different transition metals as luminescent centers. Among these ions of transition metal doped structures, Cu2+ and Mn2+ ions are attractive for light emission characteristics and for having effective properties for applications such as phosphors. The addition of these ions in ZnS structure provide defects that result in emission in the green for the Cu2+ ions and emission in orange for the Mn2+ ions. In this study, samples of pure ZnS and doped with Cu2+ and Mn2+ ions were prepared by solvotermal method, which demonstrate to be an effective process for preparing nanoparticles. Once prepared, the structures of the nanostructured samples were characterized and correlated with photoluminescent properties. The results of X-ray diffraction showed that the ZnS samples were completely crystallized without the presence of secondary phases and XRD patterns correspond to the structure of zinc blende to cubic space group F-43m. spectra XANES (X-ray Absorption Near Edge Structure) theoretical and experimental in the Zn K edge indicates that the inclusion of Mn atoms in the ZnS matrix cause the formation of Zn and S vacancies, which is confirmed by spectral adjustments EXAFS (Extended X-ray Absorption Fine Structure). These vacancies are associated with a red shift observed in the photoluminescence spectrum peak due to the addition of Mn in ZnS structure. For pure ZnS, the peak is centered at ~ 504 nm concerning the vacancies in the S nanostructured sample. As it increases the percentage of Mn in the ZnS matrix, in yellow-orange emission centered at ~ 590 nm can be observed, associated with the transition 4 T1- 6A1 inside 3d levels of Mn2+. Adding Cu2+ to the ZnS results in a broadening of the peak of the photoluminescence spectrum due to emission in blue-green, which is related to recombination deeper defect levels of electrons of t2 Cu states near the valence band.

Diploma thesis deals with the methodology of preparation of Alit – the main clinker mineral. The content of this work involves design and optimization of the methodology of preparation of pure Alit polymorphs, analysis of their properties by available analytical methods and evaluation of the change of crystallinity in the process of preparation of these polymorphs by XRD-analysis.

Electron Backscatter Diffraction (EBSD) is a well-developed technique used to perform quantitative microstructure analysis in the Scanning Electron Microscope (SEM); however, it has not been widely applied towards studying nanostructures. This work focuses on the use and limitations of EBSD in the characterization of Au nanoparticles on an MgAl2O4 substrate. Samples under investigation are prepared by depositing a thin film of Au on an MgAl2O4 substrate, and then finally heated in a furnace to induce dewetting and cluster formation. The challenges of obtaining crystallographic information from nanoparticles using EBSD are qualitatively and quantitatively described through an evaluation of the quality of the diffraction pattern at various locations of the primary electron beam on the nanoparticle. It is determined that for a high quality Electron Backscatter Diffraction Pattern (EBSP), the production of diffracted backscattered electrons travelling towards the detector must be high and the depth of the source point must be low. The top of the nanoparticle, where the local geometry of the system is similar to the geometry of a macroscopically flat sample, is found to produce diffraction patterns of the highest quality. On the other hand, reversed-contrast EBSPs are observed when the beam is positioned near the bottom of the nanoparticle. In addition, crystallographic information for each individual nanoparticle is gathered using EBSD. Each individual AuNP is observed to be single crystalline. Finally, the complete ensemble of crystalline orientations for individual nanoparticles is then compared to the global averaged crystallinity of the sample, as measured by X-ray diffraction. These results show that EBSD promises to be a powerful and robust technique in the characterization of nanoparticles. / Thesis / Master of Applied Science (MASc)

Tesis por compendio / [ES] Los sesquicalcogenuros con estequiometria B2X3, con A = Al, Ga e In y X = S, Se y Te, han recibido gran atención a lo largo de los últimos años, en particular en como modificarlos para obtener nuevas estructuras con propiedades inéditas, permitiendo su uso en una amplia variedad de aplicaciones. Si bien vías como el uso de altas/bajas temperaturas o modificar la composición química han sido bastante explotadas para modificar y obtener nuevas estructuras, las altas presiones están ganando auge como una tercera vía para obtener nuevos materiales. El uso de altas presiones implica emplear celdas de yunques de diamantes, preparadas para alcanzar altas presiones, además de altas temperaturas. A estos dispositivos se acoplan multitud de técnicas experimentales, como espectroscópicas (Raman e IR), difracción y absorción de rayos X, medidas de absorción óptica, de resistividad, etc., con el fin de estudiar como la materia evoluciona en dichas condiciones extremas. Adicionalmente, los cálculos teóricos son empleados como apoyo a los resultados experimentales. Dentro de los trabajos existentes a altas presiones de esta familia de compuestos, estos han llegado a conclusiones incluso contradictorias, arrojando más dudas acerca su comportamiento bajo presión. De todos los integrantes de estos sesquicalcogenuros, Ga2S3, In2S3 y In2Se3, han sido los más estudiados bajo presión. En esta tesis se han evaluado los efectos de la alta presión en estos tres sesquicalcogenuros, haciendo uso de espectroscopia Raman y difracción de rayos X, siempre con el soporte de los cálculos teóricos, con el fin de aclarar los resultados publicados anteriormente. Fruto de estos trabajos, la presente tesis recoge los cuatro artículos publicados en revistas indexadas. Dichos artículos han dado luz al comportamiento bajo presión de estos compuestos, como caracterización de propiedades vibracionales y estructurales bajo presión, mecanismos de transición, transiciones de fase inducidas bajo presión, así como caracterizar dichas fases de alta presión. Con todo ello, estos trabajos pretenden no solo conocer fehacientemente el comportamiento bajo presión de estos tres sesquicalcogenuros, sino impulsar futuros trabajos en el resto de los compuestos de esta familia y en otros similares, como en compuestos ternario AB2X4 con estructura tipo espinela y vacantes ordenadas. / [CA] Els sesquicalcogenurs amb estequiometria B2X3, amb B = Al, Ga, i In i X = S, Se, i Te, han rebut una gran atenció al llarg dels darrers anys, en particular sobre com modificar-los per tal d'obtindre noves estructures amb propietats inédites, permetent el seu ús en una àmplia varietat d'aplicacions. Si bé l'ùs d'altes/baixes temperatures o modificar la composició química han segut prou explotades per a modificar i obtindre noves estructures, les altes pressions estan guanyant importància com una tercera via per a obtindrer nous materials. L'ús d'altes presions implica emprar cel·les d'encluses de diamants, preparades per a assolir altes presions, a més a més d'altes temperatures. A aquestos dispositius s'acoblen multitud de tècniques experimentals, com ara espectroscòpiques (Raman i IR), difracció i absorció de raigs X, mesures òptiques, de resistivitat, etc, amb la finalitat d'estudiar com la matèria evoluciona en aquestes condicions extremes. Adicionalment, els càlculs teòrics son emprats com a recolçament dels resultats experimentals. Dins dels treballs existents a altes presions a aquesta familia de compostos s'ha arribat a determinades conclusions algunes de les quals son contradictòries, el que ha sembrat moltes dubtes al voltant del seu comportament sota pressió. De tots els integrants d'aquestos sesquicalcogenurs, Ga2S3, In2S3 i In2Se3 han sigut els més estudiats sota pressió. En aquesta tesi doctoral s'han evaluat els efectes de les altes pressions a aquestos tres sesquicalcogenurs, fent ús de l'espectroscopia Raman i la difracció de raigs X, sempre amb el suport dels càlculs teòrics, amb el fi d'aclarir els resultats previament publicats. Fruit d'aquestos treballs, la present tesi doctoral recull els quatre articles publicats a revistes indexades. Aquestos articles han vessat llum sobre el comportament sota pressió d'aquestos compostos, com ara la caracterització de les seues propietats vibracionals i estructurals sota pressió, les transicions de fase induides sota pressió i els mecanismes d'eixes transicions, així com la caracterització de les seues fases d'alta pressió. Amb tot, aquestos treballs pretenen no només conèixer el comportament sota pressió d'aquestos tres sesquicalcogenurs, sino també impulsar futurs treballs a la resta de compostos d'aquesta familia i altres compostos rel·lacionats, com ara els compostos ternaris AB2X4 de tipus espinela i de vacants ordenades. / [EN] B2X3 sesquichalcogenides (A = Al, Ga and In, X = S, Se y Te) have received special attention along last years, with great emphasis in tailor them to attain new structures to novel properties, driving them in a huge number of applications. Although high/low temperature or varying chemical composition have been extensively used to modify and obtain new structures, high pressure is gaining relevance as an alternative way to synthetised new materials. To reach such pressures and additionally high/low temperatures, diamond anvil cells are used. Many experimental techniques can be coupled to these tools to study matter under extreme conditions (Raman and IR spectroscopy, X-ray diffraction and absorption, optical absorption, and resistivity measurements, among others). Additionally, computational simulations are used to give further support to the experimental results. Despite the several existing works devoted to the behaviour under pressure of this family, controversial results have been reported. The most studied of these sesquichalcogenides have been Ga2S3, In2S3 and In2Se3. The aim of this thesis is to revisit the pressure effects by means of Raman spectroscopy and X-ray diffraction, with the help of computational simulations, for the purpose of clarify the results published earlier. The current thesis contains the four articles published in indexed journals, resulting from the study of these three sesquichalcogenides. Such articles shed light to the pressure behavior of these compounds, their vibrational and structural properties under pressure, pressure-induced phase transitions and the mechanisms behind them and characterize such high-pressure phases. With these works, we pursue not only a depth understanding of the pressure behavior of these sesquichalcogenides, but boost future high-pressure works on the rest of the family and other similar compounds, as AB2X4 with spinel structure and ordered vacancies. / The authors thank the financial support from Spanish Research Agency (AEI) under projects MALTA Consolider Team network (RED2018-102612-T) and projects MAT2015- 710, MAT2016-75586-C4-2/3-P, FIS2017-83295-P, PID2019-106383GB-41/42/43, and PGC2018-097520-A-100, as well as from Generalitat Valenciana under Project PROMETEO/2018/123 (EFIMAT). / Gallego Parra, S. (2022). Experimental and Theoretical Study of B2X3 Sesquichalcogenides under Extreme Conditions [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/191502 / Compendio

Ten thousand years ago Great Britain was a part of the European continent, where the surface of the North Sea was about 70 metres below present sea level. The large, prehistoric submerged landmass that connected the island of Great Britain to the European continent is now widely known as Doggerland. 85 samples from six different cores, which were collected from this prehistoric landscape, were studied using multi proxy -organic and inorganic- geochemical methods. Thermal analysis determined the organic matter and carbonate content, which were utilized as characterizing indices, dividing each core into various depositional units. In addition, lipid analysis studying three sets of biomarkers (n-alkanes, fatty acids and sterols), was used to distinguish between various depositional environments, especially between terrestrial and aquatic. Furthermore, the cores were mineralogically analysed using the detected clay and non-clay minerals as depositional indicators; significant states such as high and low energy environments, palaeosoil, type of weathering and stone types were identified and used to recognize any mineralogical and thus depositional alteration. Finally, the sulfur isotope analysis identified different sources of sulfur, which were then used as environmental distinguishing proxies. An integration of these analytical results provided a detailed geochemical history of each core; importantly, a Storegga tsunami deposit was detected in core ELF01A. The primary contribution of this thesis was establishing an analytical approach using combined results from a range of analytical methods. The established approach can be used to study the depositional settings for any cored sediments. / Libyan government

This thesis reports both the optimizations of the vanadium oxide (VOx) thin film as an active infrared detector material by the magnetron sputtering deposition method and its use during fabrication of proper resistors for the microbolometers. Vanadium oxide is a preferred material for microbolometers, as it provides high TCR value, low noise, and reasonable resistance, and a number of high-tech companies have used this material to obtain state-of-the-art microbolometer arrays. This material is first used in microbolometers by Honeywell, who provides its recipe with license agreements, and there is not much information in the literature for its deposition recipe. This is the first study at METU for development of vanadium oxide thin film for microbolometers. The VOx material deposition studies started by identifying the deposition parameters of the magnetron sputtering system in order to obtain proper VOx resistors for the readout electronics. The obtained recipe includes high temperature deposition conditions of VOx, however, this causes a diffusion problem on the electrodes, preventing to obtain a good contact to VOx. Also, high oxygen level in the depositions makes a contamination on the electrodes. A number of studies were done to determine a proper electrode material which is proper with the deposition conditions of the VOx. Characterization of the vanadium oxide samples is done by XRD and XPS measurements to see the relation between the phases and resistivity of the vanadium oxide. It is known that V2O5 phase provides a high TCR and resistivity value, and the XRD results show that this phase is dominant in the highly-oxygen doped or annealed resistors. The TCR and noise measurements are done using resistors implemented with the developed VOx film, after the etching processes of the both VOx and the electrodes are optimized. The contamination on the electrodes is prevented by the help of a newly designed process. The TCR measurement results show that annealing of the resistors affect the TCR values, i.e., increasing the annealing duration increases the TCR values of the resistors. Two different resistors with different deposition conditions are annealed to see the effect of annealing, where TCR results of the resistors are -0.74%/K and -0.8 %/K before annealing. The TCR values of these resistors increase to -1.6 %/K and -4.35 %K, respectively, after annealing in same conditions, showing that both the deposition conditions and annealing change the TCR significantly. Although good TCR values are obtained, the noise values of the VOx resistors are much higher than the expected values, which suggest a further study to determine the cause of this noise.