Submitted by Maicon Juliano Schmidt (maicons) on 2015-05-07T16:35:35Z No. of bitstreams: 1 Josimar Souza Rosa.pdf: 2316699 bytes, checksum: 10b8be8bf5285234719e629c53ebeb82 (MD5) / Made available in DSpace on 2015-05-07T16:35:35Z (GMT). No. of bitstreams: 1 Josimar Souza Rosa.pdf: 2316699 bytes, checksum: 10b8be8bf5285234719e629c53ebeb82 (MD5) Previous issue date: 2014-03-21 / Nenhuma / Este trabalho buscou analisar o funcionamento de um motor de combustão interna (ciclo Diesel) operando com misturas parciais de óleo diesel com gás natural veicular, e óleo de soja com gás natural veicular. Os ensaios foram realizados em um motor Agrale modelo M90, monocilíndrico, acoplado a um alternador, tendo como carga um banco de resistências. A análise realizada contemplou o desempenho em termos de consumo de combustível, potência e emissões gasosas de óxidos de nitrogênio, dióxidos de enxofre, monóxido de carbono, entre outros gases, bem como a análise da opacidade da fumaça. Os resultados mostraram que é viável a utilização de gás natural em motores ciclo Diesel sem remoção do sistema de injeção de diesel original, representando uma considerável redução nas emissões específicas dos óxidos de nitrogênio, sem perda de potência, porém resultando em combustão incompleta em altos percentuais de substituição de combustível líquido por gasoso. De maneira geral o melhor resultado em relação à eficiência foi possível com percentual de substituição de 43,7% de diesel por gás natural, no qual o conjunto motor gerador apresentou rendimento aproximado de 33,17%. A opacidade da fumaça emitida pelo motor foi reduzida significativamente quando funcionou em modo bi-combustível tanto com diesel e gás natural como óleo de soja e gás natural. / This study aims to analyze the operation of an internal combustion engine (diesel cycle) with partial mixtures of diesel oil and natural gas, and oil vegetable soybean and natural gas. The tests were carry in an engine Agrale model M90, monocilynder, coupled to alternator, and which charged a bank of resistors load. The analyses include performance fuel consumption, power and gas emissions of nitrogen oxides, sulfur dioxides, carbon monoxide, and other gases, as well the analysis of the smoke opacity. Results showed that it is feasible to use natural gas in diesel cycle engines without removing the original diesel injection system, generating a considerable reduction in specific emissions of nitrogen oxides, without loss of Power, but resulting in incomplete combustion at high percentages replacement of liquid fuel for natural gas. Generally, the Best result for efficiency was possible with replacement percentage of 43,7% of diesel per natural gas, when the generation setting showed efficiency equal at 33,17%. The smoke opacity was reduced significantly when operated in dual fuel both diesel and natural gas as soybean oil and natural gas.

abstract: Hydrogel polymers have been the subject of many studies, due to their fascinating ability to alternate between being hydrophilic and hydrophobic, upon the application of appropriate stimuli. In particular, thermo-responsive hydrogels such as N-Isopropylacrylamide (NIPAM), which possess a unique lower critical solution temperature (LCST) of 32°C, have been leveraged for membrane-based processes such as using NIPAM as a draw agent for forward osmosis (FO) desalination. The low LCST temperature of NIPAM ensures that fresh water can be recovered, at a modest energy cost as compared to other thermally based desalination processes which require water recovery at higher temperatures. This work studies by experimentation, key process parameters involved in desalination by FO using NIPAM and a copolymer of NIPAM and Sodium Acrylate (NIPAM-SA). It encompasses synthesis of the hydrogels, development of experiments to effectively characterize synthesized products, and the measuring of FO performance for the individual hydrogels. FO performance was measured using single layers of NIPAM and NIPAM-SA respectively. The values of permeation flux obtained were compared to relevant published literature and it was found to be within reasonable range. Furthermore, a conceptual design for future large-scale implementation of this technology is proposed. It is proposed that perhaps more effort should focus on physical processes that have the ability to increase the low permeation flux of hydrogel driven FO desalination systems, rather than development of novel classes of hydrogels / Dissertation/Thesis / Masters Thesis Mechanical Engineering 2019

Dans l'objectif de combler le gap entre l'offre et la demande en propène, la réaction d'oxydation déshydrogénante du propane (ODHP) est une solution alternative à la réaction de déshydrogénation directe. Les hydroxyapatites (HAp) modifiées au vanadium sont des matériaux bi-fonctionnels aux propriétés acido-basiques et redox intéressants pour cette réaction. L'objectif de cette thèse est d'étudier le comportement catalytique de ces systèmes et d'établir des relations entre structure et réactivité. Par le contrôle des conditions de synthèse et pourvu que le pH soit maintenu élevé (~9), la solution solide Ca10(PO4)6-x(VO4)x(OH)2 est obtenue dans toute la gamme de composition (x 0→ 6), alors que pour un pH inférieur, un mélange de phases d'HAps au vanadium et de Ca2V2O7 est obtenu pour x ≥ 4. Pour la solution solide, contrairement à la sélectivité en propène, la conversion en propane n'augmente pas avec la teneur en vanadium non exposé en surface. L'activation de la liaison C-H du propane s'explique par une propriété intrinsèque à la structure HAp, en lien avec la formation thermiquement activée d'anions O2- très basiques. Leur formation in situ résulte de la déshydratation progressive des colonnes d'ions OH- via le processus de conduction ionique par les protons, exalté sous conditions réactionnelles. L'organisation du vanadium sous la forme de tétramères dans Ca2V2O7 au lieu de tétraèdres isolés dans la seule solution solide favorise les échanges redox et explique l'augmentation de la sélectivité. Le contact intime entre les deux phases et la formation d'une interface cohérente permet un optimum de rendement en propène du fait de la synergie des propriétés des deux phases. / In order to fill the gap between propene supply and demand, the oxidative dehydrogenation of propane (ODHP) is an alternative solution to the direct dehydrogenation process. Vanadium-modified hydroxyapatites (HAp) are bifunctional catalysts combining acid-base and redox properties which were shown to be of interest for the ODHP reaction. In order to optimize this system, the aim of the work was to investigate the catalytic behavior of the vanadium-modified hydroxyapatites and to establish structure reactivity relationships. By peculiar attention was devoted to the control of synthesis. Provided high pH value is maintained during the synthesis, the Ca10(PO4)6-x(VO4)x(OH)2 solid solution was successfully obtained for x 0→ 6, whereas at lower pH, a mixture of Vx-HAp solid solution and of Ca2V2O7 was obtained from x ≥ 4. For the solid solution, contrary to propene selectivity, the propane conversion does not depend on the vanadium content, unexposed on the surface. The activation of the C-H bond of propane is controlled by an intrinsic properties of the HAp structure, in relation with the thermally activated formation of strong basic O2- anions. Their in situ formation results from the progressive dehydration of OH- columns via an ionic conduction process by protons that is enhanced under catalytic conditions. Due to the tetrameric environment of vanadium in Ca2V2O7 against isolated tetrahedra in the solid solution, redox exchanges are facilitated, improving the selectivity in propene. The intimate contact between the two phases and the formation of a coherent interface leads to an optimal yield in propene, due to synergistic effects of the two phases.

[pt] O presente trabalho aborda o emprego do pronome relativo que por alunos do nível superior do Instituto Nacional de Educação de Surdos (INES). Como objetivo geral, propõe-se a aplicação de uma oficina voltada ao uso do mesmo em textos acadêmicos de alunos surdos e ouvintes do Instituto. Para tal, utiliza-se uma abordagem bilíngue na qual o português escrito desempenha papel de segunda língua e a Língua Brasileira de Sinais (Libras), o de primeira. Com base em produções de alunos do programa de pós-graduação da Pontifícia Universidade Católica do Rio de Janeiro (PUC – Rio), três funções sintáticas deste pronome são selecionadas para análise, a saber, sujeito, objeto direto e adjunto adverbial. Como resultado geral, observa-se um aumento geral na produção do pronome nas três funções sugeridas. No entanto, há redução nas funções de objeto direto e adjunto adverbial no exercício de união de frases e na de adjunto adverbial no exercício com frases a serem completadas. Estes resultados são devidamente justificados, fato que comprova a eficácia da oficina para surdos e ouvintes. / [en] The present research focuses on the use of the relative pronoun que (that/where) in the production of the college students of the Instituto Nacional de Educação de Surdos (INES). Mainly, this paper proposes a workshop based on the referred pronoun in the academic writing of both deaf and listeners, college students of the Institute. In order to do so, the bilingual approach is used and the written Portuguese functions as the second language whereas the Brazilian Sign Language (Libras) functions as the first. Based on the written production of post graduation students of the Pontifícia Universidade Católica from Rio de Janeiro (PUC-Rio), three syntactic functions of the relative pronoun que (that) are selected for analysis, namely, subject, direct object and adjunct. Basically, there is general rise in the production of the pronoun for the three suggested functions. Nonetheless, there is reduction for the direct object and the adjunct in the exercise in which students may put sentences together and for the adjunct in the exercise of completing sentences. The results are properly justified what proves the efficiency of the workshop for both deaf and listeners.

L’extrusion biocatalytique, ou bioextrusion, est une technique d’extrusion réactive utilisant des enzymes comme catalyseurs. Cette technique est considérée en temps qu’étape intermédiaire, subséquente au prétraitement physico-chimique et précédente à l’hydrolyse enzymatique enréacteur fermé. L’utilisation de l’extrusion permet un procédé continu, facilement modulable et adaptable à des conditions de hautes consistances, de nombreuses biomasses et facilement transférable à l’échelle industrielle. Néanmoins, les données bibliographiques font ressortir la complexité des entrants et leurs interactions lors de la bioextrusion de biomasses lignocellulosiques. Les conclusions des bioextrusions de biomasses amidonnées soulignent l’importance de l’étude de l’influence de la concentration en substrat et en enzymes. Les résultats obtenus à partir de la bioextrusion des biomasses lignocellulosiques valident l’existence d’une activité enzymatique en extrudeuse malgré la contrainte thermomécanique et le temps de séjour limité. Lors de cette étape, l’hydrolyse de la fraction cellulosique est favorisée pour des milieux concentrés en substrat et en enzymes. Des modifications significatives des fractions cellulosiques cristallines et amorphes en surface, des réductions des tailles de particules, une dégradation visuelle des structures de la biomasse et l’augmentation de la sensibilité à la décomposition thermique, sont aussi observées sur la fraction solide. L’hydrolyse enzymatique des bioextrudats est prolongée en réacteur fermé. La bioextrusion permet des améliorations significatives des taux et vitesses de conversion des sucres sur le long terme, jusqu’à 48 h. Les gains observés sont relativement constants pour la paille de blé et augmentent avec le temps pour les écorces de bouleau et les résidus de maïs. Post-extrusion, la concentration en substrat influence négativement la conversion des sucres. Cependant, les plus-values de conversion du glucose lié à la bioextrusion de paille de blé sont principalement observables pour des concentrations en substrat et en enzymes élevées. À partir de 4 h, des baisses significatives de la conversion du xylose sont observées après bioextrusion. Les déstructurations de la fraction solide, déjà observées au cours la bioextrusion, se poursuivent en réacteur fermé. Les meilleurs résultats hydrolytiques aux niveaux des hautes charges en enzymes et en substrat sont associables aux bonnes conditions de mélanges caractéristiques des éléments bilobes. L’ensemble enzymatique est probablement réparti de façon plus homogène (mélange distributif) pour cibler plus de sites disponibles. De plus, le mélangé dispersif limite la proximité entre enzymes de même type et les gênes associées. Le procédé d’extrusion permet une agitation efficace, un bon transfert de masse et probablement un meilleur contact entre enzymes et substrat. Les moins bons résultats de conversion du xylose sont probablement à relier à des phénomènes d’adsorption non-spécifique, ou encore de désactivation des hémicellulases, provoqués par l’intensité des contraintes thermomécaniques et les résidus ligneux. Les bons résultats de déstructuration après bioextrusionsont associables à une action synergétique des contraintes mécanique et biochimique. Les analyses d’autofluorescence montrent l’évolution de la fraction ligneuse dans le processus de déconstruction de la fraction solide. Une production progressive de particules très fines,visiblement associée à la fraction ligneuse, est observée. Des complexes lignine-carbohydratessont aussi détectés dans la fraction liquide. Etant peu, voire pas hydrolysable par voie enzymatique, ces fractions hétéropolymériques sont un frein à la déconstruction. Si la déstructuration des lignines est probablement majoritairement liée au prétraitement alcalin, le procédé de bioextrusion provoque une diminution de la teneur en hétéropolymères de plus hautes masses moléculaires. / Biocatalytic extrusion, also named bioextrusion, is a reactive extrusion technique using enzymes as catalysts. Bioextrusion is considered as a link between the previous physico-chemical pretreatment (like alkaline extrusion) and the subsequent enzymatic hydrolysis in batch conditions. The extrusion allows a continuous, flexible and versatile process for high consistency media, easily transferable to the industrial level. However, complexity of both lignocellulosic biomass and lignocellulolytic enzymes and their interactions during the extrusion process are underlined by the literature. Numerous response surface methodology experiments with starchy biomass indicate that bioextrusion efficiency is mainly influenced by substrate and enzymes loading. Enzymatic activity during the bioextrusion process of lignocellulosic biomass is confirmed by the experiments despite the mechanical constraints and the limited residence time. During bioextrusion, best holocellulosic fraction hydrolysis results were obtained with high substrate and enzymes loadings. Significant modifications of the solid fraction like particule size reduction, visual deconstruction of the biomass structure, increased sensibility to thermal decomposition and the evolution of the surface exposure of crystalline and amorphous cellulose were observed. Enzymatic hydrolysis of the bioextrdates is prolonged in batch conditions. Clear improvements of speeds and rates of sugars conversion up to 48 h indicate a long term influence of the bioextrusion. Gain observed are steady for the pretreated wheat straw whereas it increases with time for corn residues and birch barks. Post-extrusion, a negative influence of the substrate loading is measured. However, best enhancements for the glucose conversion of pretreated wheat straw are detected for high substrate and enzymes loadings. From 4 to 48 h, significant losses in xylose conversion are measured with previous bioextrusion. Indicators of the solid fraction deconstruction, observed during the bioextrusion step, indicate a stronger biomass degradation after 48 h. Improvements of glucose conversion rates can be associated with good mixing conditions of the extruder, especially due to the use of kneading elements. Enzymes are probably more homogeneously distributed (distributive mixing) and can access more catalytic sites available. Moreover, dispersive mixing limits the enzyme jamming due to the biocatalysts concentration. Extrusion process permits an better agitation efficiency, good mass transfer conditions and probably a higher contact between substrate and enzymes. Lower xylose conversion results may be attributed to non-specific adsorptions or inactivation phenomena due to mechanical constraints and lignin residues. Good deconstruction results on the solid fraction may be associable with a synergetic action between mechanical and biochemical constraints. Autofluorescent signal analysis of the lignin fraction show its evolution during the deconstruction of the solid residue. During the hydrolysis, a progressive production of very small particles, appearing to be associated with the lignin fraction is observed. Lignin-carbohydrate complexes are also detected in the liquid fraction. These heteropolymeric complexes, difficult or even impossible for the enzymes to hydrolyze, are an obstacle to the biomass valorization. If lignin deconstruction is mainly due to the alkaline pretreatment, bioextrusion process seems to reduce the proportion of these heteropylymers with high molecular weights.

Metamaterials are artificial structures, which periodically arranged to exhibit fascinating electromagnetic properties, not existing in nature. A great deal of research in the field of metamaterial was conducted in a linear regime, where the electromagnetic responses are independent of the external electric or magnetic fields. Unfortunately, in linear regime the desired properties of metamaterials have only been achieved within a narrow bandwidth, around a fixed frequency. Therefore, nonlinearity is introduced into metamaterials by merging meta-atoms with well-known nonlinear materials. Nonlinear metamaterials are exploited in this dissertation to introduce and develop applications in microwave frequency with broadband responses. The nonlinearity was achieved via embedding varactor diode on to split ring resonator (SRR) design, which demonstrates tunability in resonance frequency and phase of the transmission signal. SRR exhibits power and frequency dependent broadband tunability and it is realized for external electro-magnetic signals. More importantly, the nonlinear SRR shows bi-stability with distinct transmission levels, where the transition between bi-states is controlled by the impulses of pump signal and it can be used as a switching device in microwave regime. In order to increase its functionality in other frequencies, a new design, double split ring resonator (DSRR) is introduced with two rings, which has two distinct resonance frequencies. The double split ring resonator also demonstrate similar behavior as the SRR but it is broadband. Furthermore, by designing the structure such that the inner ring has a frequency twice as outer ring resonance frequency; we observed the enhancement of harmonic generation. We exhibit enhancement in second harmonic generation and methods that can use to increase the harmonic signal power. Arranging the unit cells in an array and particular orientation further increases the harmonic power. In addition, we show that using a back plate to create a cavity will help to increase harmonic power. Furthermore, we have demonstrated that applying an external DC voltage can be used to tune resonance frequency as well as phase of the signal. Exploring these ideas in THz frequency regime is also important. So simulation results were obtained with advanced designs to achieve non-linearity in terahertz frequency regime to realize tunability, hysteresis and bi-stable states. A negative refractive index can be realized in metamaterials consisting of strong magnetic and electric resonators with responses at the same frequency band. However, high loss and narrow bandwidth resulting from strong resonances have impeded negative index optical components and devices from reaching expected functionalities (e.g. perfect lens). Here, we demonstrate experimentally and numerically that a 2D helical chiral metamaterial exhibits broadband negative refractive index with extremely low loss. With Drude-like dispersion, its permittivity leads to zero-index, and broadband chirality further brings the index to negative values for left-handed circularly polarized light in the entire range below the plasma frequency. Non-resonant architecture results in very low loss (<2% per layer) and an extremely high Figure-of-merit (>90). Tunable THz metamaterials has shown great potential to solve the material challenge due to the so-called “THz gap”. However, the tunable mechanism of current designs relies on using semiconductors insertions, which inevitably results in high Ohmic loss, and thereby significantly degrades the performance of metamaterials. In this work, we demonstrate a novel tunable mechanism based on polymeric microactuators. Our metamaterials are fabricated on the surface of patterned pillar array of flexible polymers embedded with magnetic nanoparticles. The transmission spectrum of the metamaterial can be tuned as the pillars are mechanically deformed though applied magnetic field. We observed and measured several type of deformation including bending, twisting and compressing when the applied magnetic field is polarized along different direction with respected to the axis of the magnetic particles. Compared to previous semiconductor based tunable mechanism, our structure has shown much lower loss. We demonstrate using simulations and experimentally that with an external magnetic field, we can achieve phase modulation using magnetic polymeric micro-actuators.

京都大学 / 新制・課程博士 / 博士(人間・環境学) / 甲第23976号 / 人博第1028号 / 新制||人||242(附属図書館) / 2022||人博||1028(吉田南総合図書館) / 京都大学大学院人間・環境学研究科相関環境学専攻 / (主査)教授 吉田 寿雄, 教授 田部 勢津久, 教授 中村 敏浩 / 学位規則第4条第1項該当 / Doctor of Human and Environmental Studies / Kyoto University / DFAM

This thesis is concerned primarily with the optimization of the current regulation in bi-directional ac-dc power converters through the use of appropriate current control methods. Following a review into prior current control technology, current control methods which attempt to achieve Zero Average Current Error (ZACE) in each switching period are presented. A ZACE controlled converter offers independent real and reactive power flow control with negligible low order current harmonics, a relatively narrow switching frequency band, and relative immunity to power circuit parameter variations, including DC link or AC line voltage harmonics. ZACE and other desirable characteristics in a current control method are discussed. The single phase ac and dc ripple current is characterized.Two new types of ZACE current control techniques for directly controlling the inductor current in switched power converters are introduced in this thesis together with variations for certain applications. Slope-generated hysteresis (SGH), the first to be developed, is a hysteresis method which uses the slopes of the current error signal alone to generate a hysteresis band which will result in a fixed switching frequency. Slope-generated hysteresis-clock (SGHC) is presented as an alternative with a dual clock to force a narrow switching frequency band.Ramptime current control is the second type of ZACE current control presented. Developed as an improvement over SGH, ramptime produces ZACE in each switching period by using the timing of a previous switching instant relative to the coincident previous current error signal excursion time to determine each switching instant. The digital current error polarity signal is the only variable input required to produce a pwm output.Variations of ramptime current control are also presented. Polarized ramptime is a subset of ramptime which maintains a narrow ++ / switching frequency band despite switching delays. Dual ramptime is the final enhancement of ramptime where two polarized ramptime regulators are used together to provide the appropriate choice between full-bridge and half-bridge switching in a single phase current controlled full-bridge voltage source inverter with the ac ripple current minimized without compromising the transient response. Using this technique, excellent fidelity and a narrow switching frequency band are demonstrated.The ZACE current control techniques are applied to a three phase voltage source inverter. A "standing phase" system of control for a three wire, three phase inverter is chosen over individual phase control since only two current regulators are required to control two decoupled current error signals, and the effective switching frequency is reduced by one third.The new ZACE methods are found to compare favourably in simulation to existing linear and hysteresis type current control techniques. SGH current control has equivalent fidelity to any other hysteresis control in delivering the reference current waveform, but is prone to noise in the hysteresis band determination requiring filtering. This, combined with the effect of switching delays compromises the narrowness of the switching frequency band. SGHC current control is also prone to noise in the generation of the hysteresis band, and results in a decrease in the fidelity of reproduction of the reference waveform. Ramptime current control is a robust technique, largely immune to power circuit parameter and voltage variances, with good fidelity and a relatively narrow switching frequency band. Polarized ramptime current control is shown to produce excellent fidelity with a narrow switching frequency band.The operation of the ZACE methods in single and three phase prototype converters is demonstrated. A field installation of a ++ / grid-connected ramptime current controlled converter is shown to source 20 kW of real power onto the grid from a photovoltaic array with a maximum power point tracking control, while independently providing grid voltage support through reactive power control.The effect of the synchronization of the current regulators on the ac and dc current ripple are presented. Synchronized polarized ramptime regulators are shown to produce the minimum ripple current in simulation and in the prototype operation.ZACE current control techniques, and ramptime and polarized ramptime in particular, are presented as a significant contribution to the control of current in power electronic converters.

The nature of the human brain has preoccupied philosophers and scientists for centuries. As early as the 4th Century BCE, Greek philosophers speculated that the anatomically distinct hemispheres of the brain implied specialisation of function. It was not until the "splitbrain" operations of the 1950s, however, that the precise specialisation of each hemisphere could be demonstrated. The right hemisphere apparently assumed responsibility for spacial, holistic processes, while the left hemisphere processed analytical, sequential tasks. During that same decade, educational psychologists observed two markedly different ways in which individuals perceive and relate to the world. It was later observed that these "cognitive styles" seemed directly related to the bi-polar functions of the right and left hemispheres of the brain. This implied a genetic basis for cognitive style. Subsequent research suggested that cognitive style is to a considerable extent a result of the environment of socialisation, and therefore, different cultures would demonstrate different cognitive styles. Such cultural differences in learning expectations might have serious implications for both teachers and learners in the field of export education. The literature review in this study identified physical, environmental, and experiential factors which appear to influence cognitive style. This information formed the basis of the biographical section of a questionnaire which elicited the learning style preferences of pre-tertiary students from Australia (native speakers), Indonesia and Japan. The study posed the negative hypothesis: There are no significant differences in patterns of cognitive styles between cultures. The results of the field study contradicted the negative hypothesis, identifying significant differences in patterns of cognitive styles between the three cultural groups.

歷經2008年的金融海嘯危機之後，金融業的下一步該如何走？在追求利潤的同時，如何做好風險管理？有效的管理工具是必要的，商業智慧系統工具是選項之一，本研究先藉由相關文獻探討及資料蒐集，從需求面探討金融業者於建構商業智慧系統時，應具備的功能與架構，以作為金融業者建置時的參考。 Mr. Howard Dresner首創商業智慧名詞，經過多年的發展，商業智慧系統的應用以及工具都已經很成熟，企業利用商業智慧系統做營運分析研究也很普遍。商業智慧的未來趨勢大致朝營運所需的商業智慧系統以及結構性資料與非結構性資料整併應用方向發展；另一方面，提供商業智慧軟體的廠商不斷合併，有大者恆大之趨勢。 本研究以台灣金融業實際導入商業智慧系統之種種，做為個案研究之實例。從對商業智慧系統的需求、達成目標、面臨問題、最終效益以及所投入人力物力成本等構面加以整理分析研究，以利探討金融業導入商業智慧系統之利弊，做為其他有意導入商業智慧系統業者之借鏡。 關鍵詞 : 金融業、商業智慧、個案研究