Submitted by GUILHERME RODRIGUES DE LIMA null (guirodrigueslima@hotmail.com) on 2017-09-15T18:57:55Z No. of bitstreams: 1 Defesa_correção_ficha_catalografica.pdf: 3367275 bytes, checksum: 6a436d913d3a352c3a8ec8e237660a1b (MD5) / Approved for entry into archive by Monique Sasaki (sayumi_sasaki@hotmail.com) on 2017-09-19T17:42:06Z (GMT) No. of bitstreams: 1 lima_gr_me_sjrp.pdf: 3367275 bytes, checksum: 6a436d913d3a352c3a8ec8e237660a1b (MD5) / Made available in DSpace on 2017-09-19T17:42:06Z (GMT). No. of bitstreams: 1 lima_gr_me_sjrp.pdf: 3367275 bytes, checksum: 6a436d913d3a352c3a8ec8e237660a1b (MD5) Previous issue date: 2017-08-18 / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Transistores de filme fino (TFT) são dispositivos presentes em nosso cotidiano, usados em uma ampla variedade de aplicações, desde de processadores, registradores e monitores de tela plana. Estes dispositivos apresentam diversos benefícios, tais como: transparência, flexibilidade, rapidez, baixo custo e confiabilidade, o que faz com que tenham interesse de muitos grupos de pesquisa nas últimas décadas. Este trabalho visa o desenvolvimento de um novo método de deposição por spray, em atmosfera ambiente e a baixa temperatura (350ºC), para produção de filmes finos de óxidos zinco (ZnO) aplicados como camada ativa em TFTs. Os filmes finos transparentes de ZnO foram depositados por solução de um precursor orgânico (acetato de zinco bi-hidratado (Zn(CH3COO) · 2H2O)) sobre substratos de Si-p/SiO2 pelo método de deposição por spray. Este método emprega uma automação própria de controle na deposição para obter filmes altamente homogêneos e reprodutivos. Um grande conjunto de parâmetros na deposição foram testados para otimização dos filmes semicondutores para TFTs, como por exemplo: distância do spray sobre a placa de aquecimento, tempo de deposição, número de camadas, concentração da solução, entre outros. Os resultados obtidos na caracterização dos dispositivos, como, mobilidade de saturação (µsat), tensão de limiar de operação (Vth) e razão entre a corrente de operação e a corrente intrínseca (ION/OFF), foram comparados para diferentes parâmetros de deposição utilizados. Esse trabalho contribui em utilizar um novo método de deposição de baixo custo, para possíveis aplicações industriais e que pode ser expandido facilmente para larga escala de produção na fabricação de outros dispositivos de filme fino, como, OTFTs (Organic Thin Film Transistors), células solares, LCDs (Liquid Crystal Displays), OLEDs (Organic Light Emitting Diodes), LEDs (Light Emitting Diodes) e sensores. / Thin-film transistors (TFT) are every day devices used in a wide variety of applications, like processors, recorders and flat-panel monitors. These devices that present benefits, such as transparency, flexibility, speed, lower-cost and reliability, which have attracted interest in several research groups in recent decades. The aim of this work is the development of a new method of spray deposition, in ambient atmosphere and at low temperature (350ºC), for the production of thin films of zinc oxide (ZnO) applied as active layer in TFTs. The ZnO thin films were deposited from an organic solution of zinc acetate dihydrate (Zn(CH3COO) · 2H2O) on to Si-p/SiO2 substrates by the spray deposition method. This method employs its own automation for the deposition to obtain highly homogeneous and reproducible films. A large set of parameters in the deposition were tested for optimization of the semiconductor films for TFTs, such as: distance of the spray to the hot-plate, deposition time, number of layers, solution concentration, among others. The results obtained in the characterization of the devices, such as, mobility at saturation (μsat), threshold voltage (Vth) and on/off ratio (ION/OFF), were compared for different deposition parameters. This work contributes to the development of a novel, low-cost deposition method for possible industrial applications that can be easily expanded for large scale production of other thin film devices, such as, Organic Thin Film Transistors (OTFTs), solar cells, LCDs (Liquid Crystal Displays), OLEDs (Organic Light Emitting Diodes), LEDs (Light Emitting Diodes) and sensors. / CNPq: 133952/2015-0

Cette thèse concerne la fonctionnalisation des biomatériaux, le titane et l'alliage de titane Ti6Al4V ainsi que le PEEK (Poly-Éther-Éther-Ketone) pour l'application de ces biomatériaux dans les domaines de l'implantologie dentaire et de la reconstruction maxillo-faciale. Au cours de la première partie de ce travail nous avons synthétisé quatre peptides bi-fonctionnels avec une grande affinité pour la surface implantaire de Ti et de Ti6Al4V et également pour les kératinocytes oraux. La spectroscopie de force de la cellule unique (Single Cell Force Spectroscopy - AFM) a été utilisée pour étudier l'adhésion d'une cellule sur les surfaces fonctionnalisées par les quatre peptides bi-fonctionnels. A l'aide du test colorimétrique de para-nitrophenyl phosphate (pNPP) on a démontré l'adhésion des kératynocytes après 4 heures d'incubation sur les surfaces fonctionnalisées avec les peptides bi-fonctionnels. Les résultats de ces études ont démontré la présence d'un peptide bi-fonctionnel qui augmente l'adhésion cellulaire instantanée et l'adhésion 4h après incubation des kératinocytes oraux sur les métaux. Ce peptide résiste à l'influence de facteurs externes tels que l'adsorption d'albumine et représente une proposition prometteuse pour la fonctionnalisation de l'implant de Ti et de Ti6Al4V. La deuxième partie de notre mémoire de thèse décrit une méthode de dépôt par spray des films des multicouches de PLL/PGA (poly-l-lysine/acide polyglutamique), des protéines et des cellules souches pulpaires. Les outils de spray d'usage unique ont été adaptés aux exigences de la bonne pratique de fabrication (GMP - good manufacturing practice). Les premiers tests de prolifération cellulaire ont démontré qu'elle n'a pas été affectée par le spray. L'étude en AFM a démontré que la rugosité et l'épaisseur du film augmentaient exponentiellement avec l'augmentation du nombre des couches déposées. Le traitement physique par UV rayonnement ainsi que le traitement par la déshydratation et la réhydratation des films ont provoqué des changements dans l'épaisseur, l'élasticité et la dureté des films. Le dépôt des protéines sur les MPEs a aussi augmenté l'épaisseur et a influencé la dureté de la surface. Les changements chimiques de la structure des MPEs après le traitement physique et après le dépôt des protéines naturelles ont été étudiés par la spectroscopie Raman. La prolifération cellulaire au 1er, 3e et 8e jours après leur spray sur des films de MPEs et des protéines a été ensuite évaluée. Les MPEs traitées par UV combiné avec déshydratation/réhydratation ainsi que les PEMs couvertes par protéine - CaP ont entrainé une meilleure adhésion et prolifération cellulaires que les MPEs non-traitées. Finalement la méthode de dépôt par spray des MPEs, protéines et aussi des cellules souches pulpaires a été appliquée sur la surface de PEEK. La meilleure prolifération cellulaire au 8e jour après le spray était sur la surface couverte par le film de (PLL-PGA)5-protéine/CaP. Une étude in vitro sur le degré de minéralisation au 21e jour après l'incubation des cellules pulpaire dans un milieu ostéconductuer sur des différentes (MPEs couvertes-PEEK) surfaces a été effectuée. Les résultats de la microscopie électronique à balayage (MEB), microscopie électronique à transmission (MET), combiné avec des études histologiques ont confirmé la formation d'une matrice extracellulaire minéralisée des autour des cellules pulpaires sur la surface de PEEK. Conclusions: Dans ce travail nous avons décrit une nouvelle approche de fonctionnalisation des surfaces de Ti and Ti6Al4V par des peptides bi-fonctionnels en proposant une séquence prometteuse qui augmente l'adhésion des kératinocytes oraux. Ensuite nous avons développé une méthode de fonctionnalisation de la surface de PEEK par des multicouches de polyeléctrolytes, des protéines naturelles et des cellules souches de la pulpe dentaire. La différentiation ostéoblastique in vitro a été finalement évaluée. / The objective of this thesis was to develop new techniques of surface functionalization of titanium; titanium alloy (Ti6Al4V) and PEEK (poly-ether-ether ketone) surfaces for their application on dental implantology and maxillofacial surgery. During the first part of the thesis we have synthesized four metal binding-cell specific peptides (MCSPs) with high affinity to titanium surface and to oral keratinocytes cells. Single Cell Force Spectroscopy (AFM) was used to study the instantaneous cell adhesion force of keratinicyte cell on MCSPs functionalized surfaces. The colorimetric para-nitrophenyl phosphate (pNPP) essay demonstrates the surface cell adhesion four hours after incubation. The results demonstrate the presence of one bi-functional peptide (MCSP-2) who increases both: the instantaneous and the 4 h cell adhesions. MCSP-2 resist to the influence of external factors like BSA adsorption and could be an interesting candidate for implant surface functionalisation. In the second part of the thesis we have developed a spray deposition method of polyelectrolyte multilayer (PEM) films build. PLL/PGA (poly-l-lysine/poly-glutamic acid) and proteins were used for surface coating. Consequently dental pulp stem cells (DPSC) are sprayed on the PEM films. The aims were to improve a spray -method for cells and the polyelectrolytes deposition on the PEEK implant. The entire spray device was designed for single use, which correspond to good manufacturing practice (GMP) conditions. Cell proliferation in 24 hours after spraying was not disturbed by the spray. Physicochemical properties of PEMs deposited by spray on glass surfaces were performed by Atomic Force Microscopy (AFM) and by contact angle measurements. The results have demonstrated the changes in films thickness and films roughness with increasing numbers of layers corresponding to exponential growth of the films. Physical treatment by UV irradiation and drying-wetting process affects the film thickness and the film elasticity and increases the stiffness of the film. The deposition of protein-CaP and collagen coatings on PEM films increased the layer thickness and influenced the hardness of the surface. Chemical changes in the polyelectrolyte structure during the physical treatment and after proteins deposition were studied by Raman spectroscopy. Cell proliferation of the pulp cells at 1st, 3th and 8th days after pulp cells deposition on PEMs coated glass surfaces, was then evaluated. The results demonstrated that 10 UV/ dray/wetted films and the natural proteins coated films enhanced cell adhesion and cell proliferation. The protein-CaP PEMs covered surface creates the best microenvironment to ensure the cell behavior. Finally PEM films coatings are applied on PEEK implant surface. The AFM study shows the changes of homogeneity and roughness of this surface after PEM film deposition. Contact angle measurement demonstrates decreases of surface hydrophobicity. Cell proliferation of dental pulp stem cells (DPSC) on (PLL-PGA)5-protein/CaP coated PEEK surface was highest compared to other functionalized surfaces. In vitro study of DPSCs osteogenic differentiation was evaluated by the degree of mineralization of the extracellular matrix on the PEEK surface at 21st day after cell incubation. Scanning electron microscopy (SEM), transmission electron microscopy (TEM) combined with histological studies improved the formation of mineralized extracellular matrix and confirmed the osteogenic differentiation of DPSCs on the PEMs coated PEEK surface. Conclusions: In this work we validated the method of Ti and Ti6Al4V functionalization with bi-functional peptides. One peptide that could increase the epithelial cell adhesion to the surface was proposed. Spray deposition technics of PEMs, protein and pulp stem cells were applied for PEEK implant functionalization. Finally we evaluated the differentiation of dental pulp stem cells on the PEEK surface in vitro.

With the ever-advancing technology, there is an incessant need for reliable electrochemical energy storage (EES) components that can provide desired energy and power. At the forefront of EES systems are electrochemical capacitors (ECs), also known as supercapacitors that typically have higher power and superior cycle longevity but lower energy densities than their battery counterparts. One of the routes to achieve higher energy density for ECs is using the hybrid EC configuration, which typically utilizes a redox electrode coupled with a counter double-layer type electrode. In this dissertation, both scale-up (coin-cell type) as well as scale-down (on-chip miniaturized) hybrid ECs were designed, constructed and evaluated. The first part of the dissertation comprised material identification, syntheses, and electrochemical analyses. Lithium titanate-anatase titanium oxide (Li4Ti5O12-TiO2) composites were synthesized via electrostatic spray deposition (ESD) and characterized in both half-cell and full-cell assembly against lithium and nanostructured carbon based counter electrodes, respectively. The second redox type material studied for hybrid electrochemical capacitors was ESD derived manganese oxide (MnOx). The MnOx electrodes exhibited a high gravimetric capacitance of 225F g-1 in aqueous media. Further improvement in the rate handling of the MnOx electrodes was achieved by using CNT additives. The MnOx-CNT composites were tested in full-cell assembly against activated carbon counter electrodes and tested for different anode and cathode mass ratios in order to achieve the best energy-power tradeoff, which was the second major goal of the dissertation. The optimized hybrid capacitor was able to deliver a high specific energy density of 30.3 Wh kg-1 and a maximal power density of 4kW kg-1. The last part of the dissertation focused on a scale-down miniaturized hybrid microsupercapacitor; an interdigitated electrode design was adopted in order to shorten the ion-transport pathway, and MnOx and reduced graphene oxide (rGO) were chosen as the redox and double layer components, respectively. The hybrid microsupercapacitor was able to deliver a high stack energy density of 1.02 mWh cm-3 and a maximal stack power density of 3.44 W cm-3, both of which are comparable with thin-film batteries and commercial supercapacitor in terms of volumetric energy and power densities.

No description available.

Zoysiagrass (Zoysia spp.) is utilized as a warm-season turfgrass because of its density, visual quality, stress tolerance, and reduced input requirements. Turf managers often exploit winter dormancy in warm-season turfgrass to apply nonselective herbicides such as glyphosate and glufosinate to control winter annual weeds. Although this weed control strategy is common in bermudagrass (Cynodon spp.), it has been less adopted in zoysiagrass due to unexplainable turf injury. Many university extension publications recommend against applying nonselective herbicides to dormant zoysiagrass despite promotional language found in a few peer-reviewed publications and product labels. Previous researchers have used vague terminology such as "applied to dormant zoysiagrass" or "applied prior to zoysiagrass green-up" to describe herbicide application timings. These ambiguous terms have led to confusion since zoysiagrass typically has subcanopy green leaves and stems throughout the winter dormancy period. No research has sought to explain why some turfgrass managers are observing zoysiagrass injury when the literature only offers evidence that these herbicides do not injure dormant zoysiagrass. We sought to explore various herbicides, prevailing temperatures surrounding application, heat unit based application timings, and spray penetration into zoysiagrass canopies as possible contributors to zoysiagrass injury. The results indicated that a wide range of herbicides may be safely used in dormant zoysiagrass. However, as zoysiagrass begins to produce more green leaves, herbicides such as metsulfuron, glyphosate, glufosinate, flumioxazin, and diquat become too injurious. Glufosinate was consistently more injurious regardless of application timing than glyphosate and other herbicides. When temperatures were 10 °C for 7 d following treatment, a delayed effect of glyphosate and glufosinate effect on digitally-assessed green cover loss was noted on zoysiagrass sprigs. In subsequent studies on turf plugs, a 14-d incubation period at 10 °C reduced glyphosate but not glufosinate effects on turf green color reduction. Glyphosate applied at 125, and 200 GDD5C can safely be applied to zoysiagrass while glufosinate applied at the same timings caused inconsistent and often unacceptable zoysiagrass injury in field studies conducted at Blacksburg, VA, Starkville, MS, and Virginia Beach, VA. Zoysiagrass green leaf density was described as a function of accumulated heat units consistently across years and locations but variably by turf mowing height. Turf normalized difference vegetative index was primarily governed by green turf cover but reduced by herbicide treatments, especially when applied at greater than 200 GDD5C. Substantial spray deposition occurred to subcanopy tissue regardless of nozzle type, pressure and height above the zoysiagrass canopy based on spectrophotometric assessment of a colorant admixture. However, increasing nozzle height above the turf canopy and avoiding air induction type nozzles significantly reduced the percentage of green tissue exposed at lower canopy levels. Absorption of radio-labeled glyphosate and glufosinate was up to four times greater when exposed to zoysiagrass stems compared to leaves. Glyphosate translocated more than glufosinate and both herbicides moved more readily from stem to leaf than from leaf to stem / Doctor of Philosophy / Zoysiagrass (Zoysia spp.) is utilized as a warm-season turfgrass because of its density, visual quality, stress tolerance, and reduced input requirements. Being that zoysiagrass is a warm-season turfgrass, it enters a dormancy period during the winter months. During this period, zoysiagrasses' active growth is halted, and leaves lose their green color and turn a golden-brown color. The winter dormancy period presents turfgrass managers with a unique opportunity to apply nonselective herbicides such as glyphosate and glufosinate to control a broad spectrum of winter annual weeds. Although this weed control strategy is common in bermudagrass (Cynodon spp.), it has been less adopted in zoysiagrass due to turfgrass managers observing unexplainable turfgrass injury. Many university extension publications recommend against applying nonselective herbicides to dormant zoysiagrass despite language found in peer-reviewed publications and product labels suggesting they could be safely applied. Previous researchers have used vague terminology such as "applied to dormant zoysiagrass" or "applied prior to zoysiagrass green-up" to describe herbicide application timings. These terms have led to confusion about when to make these applications since zoysiagrass typically has subcanopy green leaves and stems throughout the winter dormancy period. No research has sought to explain why some turfgrass managers observe zoysiagrass injury when the literature only offers evidence that these herbicides do not injure dormant zoysiagrass. Research projects were designed to explore various herbicides, temperatures surrounding herbicide applications, application timings, and spray penetration into zoysiagrass canopies as possible contributors to zoysiagrass injury. The results indicated that a wide range of herbicides may be safely used in dormant and semidormant zoysiagrass. However, as zoysiagrass begins to produce more green leaves and stems, herbicides such as metsulfuron, glyphosate, glufosinate, flumioxazin, and diquat become too injurious and should be avoided. Across multiple research studies, glufosinate was consistently more injurious regardless of application timing than glyphosate and other herbicides. When temperatures were 10 °C for 7-d following treatment, it delayed zoysaigrass response to glyphosate and glufosinate. In a subsequent study, when temperatures were at 10 °C for a 14-d period, glyphosate and the nontreated reached 50% green cover at the same time, which suggests cold temperatures could mitigate glyphosate injury on zoysiagrass over a 14-d period. The 10 ° temperature only delayed glufosinate injury on zoysiagrass, and no safening was observed. The results also indicated that as temperatures increased, glyphosate and glufosinate rate in which injury was observed increased on the zoysiagrass. Glyphosate applied at 125, and 200 GDD5C can safely be applied to zoysiagrass while glufosinate applied at the same timings caused inconsistent and often unacceptable zoysiagrass injury in field studies conducted at Blacksburg, VA, Starkville, MS, and Virginia Beach, VA. Zoysiagrass injury increased when glyphosate and glufosinate were applied later into the spring when more green leaves were present regardless of location. Accumulated heat units and zoysiagrass green leaf density were closely related, indicating that accumulated heat units could be a useful tool for turfgrass managers to track zoysiagrass spring green-up. Substantial spray deposition was found on subcanopy zoysiagrass leaves and stems regardless of nozzle type, pressure, and height above the zoysiagrass canopy based on recovered colorant at the upper, middle and lower levels of the zoysiagrass canopy. However, avoiding air induction-type nozzles and raising spray height may slightly decrease penetration of spray droplets into a zoysiagrass subcanopy, but a large percentage of droplets still reached the middle and lower canopy layers in this research. Absorption of radio-labeled glyphosate and glufosinate was up to four times greater when applied directly to zoysiagrass stolen compared to leaves. Glyphosate translocated more than glufosinate, and both herbicides moved more readily from stem to leaf than from leaf to stem. These data suggest limiting the number of green zoysiagrass leaves at application would be an effective method to avoid injury zoysiagrass when applying nonselective herbicides

No description available.

Indiana University-Purdue University Indianapolis (IUPUI) / Fabrication and analysis of Copper Indium Gallium di-Selenide (CIGS) nanoparticles-based thin film solar cells are presented and discussed. This work explores non-traditional fabrication processes, such as spray-coating for the low-cost and highly-scalable production of CIGS-based solar cells. CIGS nanoparticles were synthesized and analyzed, thin CIGS films were spray-deposited using nanoparticle inks, and resulting films were used in low-cost fabrication of a set of CIGS solar cell devices. This synthesis method utilizes a chemical colloidal process resulting in the formation of nanoparticles with tunable band gap and size. Based on theoretical and experimental studies, 100 nm nanoparticles with an associated band gap of 1.33 eV were selected to achieve the desired film characteristics and device performances. Scanning electron microcopy (SEM) and size measurement instruments (Zetasizer) were used to study the size and shape of the nanoparticles. Electron dispersive spectroscopy (EDS) results confirmed the presence of the four elements, Copper (Cu), Indium (In), Gallium (Ga), and Selenium (Se) in the synthesized nanoparticles, while X-ray diffraction (XRD) results confirmed the tetragonal chalcopyrite crystal structure. The ultraviolet-visible-near infra-red (UV-Vis-NIR) spectrophotometry results of the nanoparticles depicted light absorbance characteristics with good overlap against the solar irradiance spectrum. The depositions of the nanoparticles were performed using spray-coating techniques. Nanoparticle ink dispersed in ethanol was sprayed using a simple airbrush tool. The thicknesses of the deposited films were controlled through variations in the deposition steps, substrate to spray-nozzle distance, size of the nozzle, and air pressure. Surface features and topology of the spray-deposited films were analyzed using atomic force microscopy (AFM). The deposited films were observed to be relatively uniform with a minimum thickness of 400 nm. Post-annealing of the films at various temperatures was studied for the photoelectric performance of the deposited films. Current density and voltage (J/V) characteristics were measured under light illumination after annealing at different temperatures. It was observed that the highest photoelectric effect resulted in annealing temperatures of 150-250 degree centigrade under air atmosphere. The developed CIGS films were implemented in solar cell devices that included Cadmium Sulfide (CdS) and Zinc Oxide (ZnO) layers. The CdS film served as the n-type layer to form a pn junction with the p-type CIGS layer. In a typical device, a 300 nm CdS layer was deposited through chemical bath deposition on a 1 $mu$m thick CIGS film. A thin layer of intrinsic ZnO was spray coated on the CdS film to prevent shorting with the top conductor layer, 1.5 μm spray-deposited aluminum doped ZnO layer. A set of fabricated devices were tested using a Keithley semiconductor characterization instrument and micromanipulator probe station. The highest measured device efficiency was 1.49%. The considered solar cell devices were simulated in ADEPT 2.0 solar cell simulator based on the given fabrication and experimental parameters. The simulation module developed was successfully calibrated with the experimental results. This module can be used for future development of the given work.