Dissertations / Theses on the topic 'Pump parameters'

This paper presents the development of a helicopter axial piston pump model with condition monitoring in mind. Industrial constraints and needs ask for modelling with a lumped-parameter approach and require model architecture to be addressed with care. The aim of the proposed model is to assess the merits of pump leakage monitoring through measurement of case pressure. Once reviewed the state of the art in pump modelling, the slipper/swashplate interface is taken as an example to propose and implement in Simcenter AMESim a variable gap height model. The simulation results show that commonly used lumped-parameter models overestimate leakage. It also points out that average leakage at slipper may reverse at high pump displacement.

Abstract The objective of this thesis was to determine the effects of design, operational and furnish quality parameters on pressure screen and hydrocyclone performance. The general contradictory interrelationships between capacity and selectivity in pressure screening and cleaning are commonly recognized, but deep understanding of the effects of design, operational and furnish quality parameters on the state of operation is missing. As separation selectivity is closely dependent on thickening and pulp passage, an operation curve for separation was applied and its application further developed to examine the parameters affecting pressure screen and hydrocyclone separation. New information was found on the geometry of the screen plate, furnish quality parameters in pressure screen fibre fractionation, and the hydrocyclone separation of fibres, sand and gases. The capacity increases achieved by changes in the wire screen plate geometry were found to be achieved at the cost of separation selectivity in probability screening. The capacity of the screen plate was affected by the flow on the screen plate and through it. The hydraulic resistance both in the forward and reverse flow directions was found to be of great importance for the capacity of the screen plate. Previously unreported knowledge was found regarding the effects of wire width, height and shape. Pressure screening capacity was found to decrease with increasing fibre length, fibre network strength and flocculation. Pressure screen fibre fractionation selectivity was increased by broadening of the fibre length distribution of the feed furnish. The furnish properties also affected the separation selectivity of fibres, sand and gases in the hydrocyclone. An increase in fibre network strength reduced the separation selectivity of the hydrocyclone separation of fibres and sand. Any increase in the specific surface area, and especially in the amount of fines, was found to make gas removal more challenging. It was concluded that a broader range of the specific surface distribution can increase the selectivity of fibre fractionation in the hydrocyclone. Knowledge of the general effects of design, operational and furnish quality parameters on the performance of pressure screen and hydrocyclone separation was deepened as a result of this work, which provides a framework for studying these effects further in pursuit of the general objective of maximizing capacity and selectivity while minimizing energy and investment costs.

This thesis deals with centrifugal pump impeller design for given parameters. This pump impeller design consists of the calculation of basic dimensions, the meridional flow channel design and blade design. Complete design of the pump impeller is afterwards simulated in CFD programme.

This diploma thesis deals with hydraulic design and optimization of the blades of the axial pump. Main objective of the thesis is to design two stage pump with counter-rotating rotors meeting conditions of design point. In addition to the design solution the thesis includes theoretical part which deals with dividing and function description of hydrodynamic pumps.

The presteaming of wood chips is an important step in the chemical pulping industry. It removes the air from within wood chips, allowing the cooking liquor to better impregnate wood chips, which leads to a more uniform cooking process, and lowers the amount of rejects. When steaming at atmospheric pressure, it is important that the temperature of the wood chips reach 100ᴼ C, as otherwise there will be an equilibrium leaving some air left inside. Having poorly steamed chips in a process could cause severe problems when it comes to reaching the targeted kappa number, or having the adequate retention time in the digester. There are a few different ways in which the wood chips are presteamed within the industry, however, there is little experimental data regarding the heating time of wood chips that can be used when designing these systems. Most studies have mainly focused on the air removal, or improvement of the impregnation step, and the few studies that have included the heating of the wood chips were limited to only one type of wood chip, or failed to specify the experimental details. Therefore, handmade wood chips pine and birch, two tree species commonly found in Sweden, were steamed in an ATEX designed digester with a steam jacket. The wood chips had thermocouples inside them and the temperature and time was recorded, and the effect of different parameters on the heating could thus be studied.The results revealed that there could be more than a minute in average time difference between wood chips of different thicknesses, both for birch and pine, although the difference in heating time was more linearly correlated to thickness for the birch chips. Pine chips of different thickness were also studied when the pressure inside the digester was allowed to build up, which showed that it is mainly thicker chips that have reduced heating time under such circumstances, as the thinner chips stop heating for a while when the steam condensates on colder surroundings. When comparing heartwood and sapwood chips, it was noted that the difference in heating time could be around 1 minute at most for pine, but only a few seconds for birch. This was most likely due to the pine heartwood and sapwood having distinct moisture contents, 25 % and 58 % respectively, while it was 41% and 42 % in birch heartwood and sapwood. Birch and pine chips wee also steamed together, however, the difference in heating time was only a few seconds on average. When comparing these experimental results with simulation data of the steaming of wood chips, it fit rather well when it came to the general heating time. However, the effect of increased moisture content had a much larger impact in the simulations, which predicted that more moist wood chips would need several minutes more steaming time, while the experiments only showed at difference of, at most, around 1 minute. When comparing with old experimental data, that has been the basis for the design of older steaming processes, it gave very distinct results, where the effect of thickness did not have as big of an impact as in the old data. No further comparison could be made, however, as the experimental conditions for the old experimental data were not known. Based on these results, it was noted that a steaming time of at least 5 minutes would be needed to ensure that even the largest and more moist chips could reach 100ᴼ C in this system. Finally, the condensate from the handmade birch and pine chips was analyzed. It revealed the presence of low molecular weight compounds like methanol, formic acid and acetic acid. Common metal ions were also present,although the amount of sodium ions clearly surpassed the rest. The pH of the pine condensate was measured and it was very high, which implies that the condensate was contaminated.<br>Basning av flis är ett viktigt steg inom kemisk massaindustri. Det avlägsnar luft från flisens insida vilket gör att impregneringen av luten blir bättre, vilket i sin tur leder till en jämnare kokning och färre rejekt. När basningen sker vid atmosfärstryck är det viktigt att flisen når en temperatur på 100ᴼ C, annars kommer det finna ett jämviktstillstånd där lite luft blir kvar på insidan. Att ha otillräckligt basad flis i en process skulle kunna orsaka stora problem när det gäller att nå önskade kappatal, eller att ha en önskad retentionstid i kokaren.Basningen görs på ett par olika sätt inom industrin, men det finns väldigt lite experimentell data tillgänglig angående flisens upvärmning, som skulle kunna användas när dessa system designas. De flesta vetenskapliga studier har fokuserat på luftborttagningen eller på förbättringar av impregneringssteget, medan de få studier som inkluderat mätningar av temperaturen ofta varit begränsade till ett slags trä, eller så har de inte inkluderat detaljer kring experimentet. Därför basades handgjorda flisbitar av björk och tall från Sverige i en ATEX-designad kokare med en ångjacka. Flisen hade termoelement inuti och temperaturen samt tiden kunde avläsas, vilket gjorde det möjligt att studera effekten av olika parametrar. Resultaten visade att det kunde skilja mer än en minut i uppvärmningstid mellan flisbitar av olika tjocklekar, både för tall och björk, även fast skillnaden i uppvärmningstid var mer linjärt relaterad till tjockleken för björkflisen. Tallflisen studerades också när trycket inuti kokar tilläts stiga vilket visade att det de tjockare flisbitarnas uppvärmningstid som kortas ned mest, eftersom de tunnare flisbitarna slutar värmas upp när ångan börjar kondensera på kallare ytor runt omkring. När flis av splintved och kärnved jämfördes visade det sig att skillnaden i uppvärmningstid kunde vara omkring 1 minut för tall, men endast ett par sekunder för björk. Detta beror troligtvis på att kärnveden och splintveden i tall hade stora skillnader i fukthalt, 25 % respektive 58 %, medan det för björk var 41 % och 42%. Björkflis och tallflis basades även tillsammans men det skillde bara ett fåtal sekunder i genomsnitt i uppvärmningstid. När den experimentella datan jämfördes med data från simuleringar visade det sig att de stämmer väl överens när det gäller uppvärmningstiden i allmänhet. Å andra sidan förutspådde simuleringsdatan att en ökad fukthalt skulle leda till flera minuters skillnad i uppvärmningstid, medan endast 1 minuts skillnad uppmättes. När jämförelser gjordes med gammal experimentell data som använts som grund för tidigare processers design, var resultaten ganska olika eftersom den gamla datan visade en större effekt av ökad tjocklek än den som uppmättes.Tyvärr kunde inte fler jämförelser göras eftersom detaljerna kring experimentet bakom den gamla datan inte var kända. Slutligen analyserades även kondensatet från de handgjorda flisbitarna av tall och björk. Det visade att det fanns små mängder av små polära organiska ämnen, såsom metanol, myrsyra och ättiksyra. Vanliga metalljoner detekterades också, där mängden natrium var klart större än övriga metalljoner. Tallkondensatets pH mättes och det visade sig vara väldigt högt, något som tyder på att det troligtvis var förorenat.

An investigation has been carried out to determine the factors controlling the wear characteristics of disc poppet valves in reciprocating slurry pumps used in the transportation of quartzite slurries. A laboratory test rig has been designed and built which closely simulates the operating conditions experienced by slurry pump valves. Experiments have been conducted to determine the effect of the design parameters, namely - slurry constitution, valve closure velocity and valve angle, on the wear resistance of a low alloy steel, as a function of its mechanical properties. It has been shown that the wear of the valves is a sensitive function of the operating parameters. Significant improvements in the life of the valves can be achieved through increasing material hardness, reducing valve closure velocity, slurry density and valve angle. A detailed study has been made of the mechanisms contributing to valve wear. It has been established that both percussive impact and three body abrasion wear mechanisms predominate. The influence of each mechanism has been shown to be a function of the slurry constitution and the material hardness.

Understanding how different processing variables influence wood welded bonds is vital if the technique will ever be used to create engineered lumber without using adhesives. A variation of vibration welding, wood welding uses pressure and friction to bond materials together. During welding, heat causes a softening in the wood, a naturally occurring composite material. This softening leads to fiber entanglement and a bond forms upon cooling. The goal of this research was to investigate several processing aspects of the wood welding procedure. A prototype wood welding machine, designed and fabricated from the ground up, was used to investigate the effects of various welding parameters using birch wood. Wood welds were evaluated on the basis of bond coverage and ultimate shear strength. Four experiments were performed: welding frequency and duration interaction, grain orientation effects, alternative welding completion metrics, and strength development over time. During the wood welding process, three distinct phenomena were repeatedly observed: smoke creation, welding residue formation, and an audible pitch change. The presence of each was recorded for every wood welded specimen and used later in additional data analysis. Investigating each of the welding phenomena was done in an attempt to better characterize when fusion was achieved at the weld interface. ImageTool, an image analysis software package, was used to investigate and quantify the often irregular bonds exposed after shear fracture. The results of the various welding variables were analyzed on the basis of shear strength and bond uniformity. From the birch samples, it was shown that better bonds result from lower welding frequencies and longer welding durations. The grain orientation analysis demonstrated that welding orientation marginally affects the average shear strength of the wood weld. The data from the alternative welding metrics suggests that welding time is not a quality indicator of welding completion (bond coverage). The strength development trials confirmed previous research; wood welds obtain most of their strength in a relatively short period of time. Douglas fir and poplar both proved to be weldable for the first time, but they were sufficiently weaker than birch. When welding was attempted with Douglas fir under similar pressures used for birch, Douglas fir samples would commonly “washboard.” With reduced welding pressure, Douglas fir formed wood welds more easily.

O transporte de minérios através do bombeamento de polpa é relevante em escala mundial. No Brasil este modo de transporte é muito importante devido à enorme produção mineral e suas distâncias continentais. E, o bombeamento de polpa em planta é ainda mais importante pois é uma operação diária que afeta a todos os envolvidos. A motivação para este estudo foi providenciar para a Escola Politécnica uma estação de bombeamento capaz de levantar os parâmetros do escoamento necessários para o correto dimensionamento das linhas de polpa. Esta dissertação descreve a montagem de dois loops (3\'\' e 4\'\'), devidamente instrumentado e com a aquisição direta dos dados via computador. Os loops foram dimensionados, os componentes, bomba e instrumentos adquiridos, o loop montado, calibrado e colocado em marcha. Esta dissertação registra esta experiência e discute as dificuldades encontradas, na expectativa de que este sistema de bombeamento venha a ser útil para futuros pesquisadores. A Escola Politécnica agora dispõe de um loop de bombeamento de polpa mineral adequado para a determinação de parâmetros hidráulicos, pesquisa e suporte para futuros projetos.<br>Ore transportation via slurry pumping is relevant in a world scale. In Brazil, due to its huge mineral production and continental distances, mineroducts are an important transportation mode. And, in plant slurry pumping is still more important as it is a dayby- day operation that affects everybody. The motivation for this study was to provide Escola Politécnica (USP) of a convenient pumping station (loop) able to measure the necessary flow parameters for proper design of slurry lines. This dissertation describes the design of two loops (3\'\' and 4\'\') full instrumented and with direct data acquisition via computer. The loops have been sized, components, pump and instruments purchased, erected and started-up. This dissertation registers this experience and discusses the difficulties found, in the expectative can become useful for other researches. Escola Politécnica has now a proper slurry pumping loop for hydraulic determinations, research and for support of future projects.

There are several benets of electrohydraulic power steering systems, as compared to hydraulicpower steering systems where the pump is driven directly by the engine of the vehicle. Someof these benets are increased eciency and improved steering performance. The purpose ofthis project is to create a simulation model of the electrohydraulic power steering system inSimulink, excluding the hydraulic circuit. The model should thus consist of the electric motor,the drive electronics, the control system, the hydraulic pump as well as the communication andinterface to the master simulation system in which the model will be used.As a start a mathematical model of the motor is derived. Then the motor controller includingtwo current controllers and a speed controller is developed. The switching signals for the threephase bridge that drives the motor are calculated using space vector modulation. The motordrives a hydraulic pump, which is modeled using data sheet eciency curves. Finally a thermalmodel of the drive is developed. To fulll real time requirements, a lumped parameter approachis chosen. The nal model is exported as a Functional Mock-up Unit, which is a black-boxencapsulation of the complete simulation model.The simulation model is compared to measurement data to conrm its validity. Thesecomparisons shows that the dynamic response of the motor and its controller are close to themeasured values and that the thermal model adequately corresponds to the thermal tests. Thehydraulic pump model varied from measurements more than the other sub-modules. It was,however, seen as acceptable. Overall the system response was satisfactory, but naturally a lotof future improvements and new features could be made to improve the model.<br>Det finns flera fördelar med elektrohydraulisk servostyrning, där hydraulpumpen drivs av en el-motor, jämfört med hydraulisk servostyrning, där pumpen drivs direkt av fordonets förbränningsmotor. Några av dessa fördelar är ökad effektivitet och förbättrad styrprestanda. Syftet med detta projekt är att skapa en Simulink-modell av ett elektrohydraulisk system för servostyrning, exklusive hydraulkretsen. Modellen ska alltså bestå av delmodeller för elmotorn, drivelektroniken, styrsystemet, hydraulpumpen samt kommunikation med den övergripande simuleringsplattformen.Inledningsvis beskrivs en matematisk modell av elmotorn och efter det utvecklas motorstyrningen, bestående av två strömregulatorer samt en hastighetsregulator. Spänningen från strömregulatorerna uppnås genom space vector-modulation, som beräknar de pulskvoter som krävs för att uppnå denna spänning. Elmotorn driver en pump. Denna pump modelleras med hjälp av data från pumpens datablad. Slutligen modelleras drivelektronikens termiska egenskaper med ett termiskt nätverk. Den slutliga modellen omsluts av en Functional Mock-up Unit somintegreras i den övergripande simuleringsplattformen.

Oscillating positive displacement pumps are used in many industrial sectors. Mechanical stroke generators / drives such as crank drive, spring-cam drive etc have reached a high technological level, but to which are set mechanical limits. Especially in the smallest dosing range <1 l/h at a pressure range from 100 … 400 bar considerable optimisation is still required with regard to precision and continuity / control range of the dosing flow. In order to expand the current application possibilities for the diaphragm metering pump technology, it is necessary to use new drive systems such as linear motor technology. A linear motor is an electric drive unit which transmits the oscillating delivery movement of the dosing pumps directly to the displacer (hydraulic piston, diaphragm, etc.) without any mechanics, so that highly dynamic movements can be carried out with maximum precision, an individual kinematic profile and a control range of 1:200. The examples of gas odorization and filling processes show how the linear motor drive can be used to technologically solve and even optimize the customer's process requirements. The linear motor pump can realize an integrated 3-parameter control and is therefore suitable for almost any kinematically solvable dosing task.

The wastewater treatment process is one of the most important processes which contributes to the protection of the environment. This process can also potentially recover necessary and scarce raw materials, such as phosphorus. Research of the wastewater treatment technology is an increasingly relevant topic and more innovative knowledge should be gradually implemented into existing plants. However, the implementation of such technology involves increased investment and often operating costs. This is, why there is a growing interest in improving the energy intensity and hydraulic efficiency of the installed wastewater plant machinery. The optimization of operating parameters in such machinery can also bring significant savings, which can be potentially re-invested into other technologies. This work deals with the issue of proper evaluation of installed machinery for the selection of operating parameters and assessment of their significance. As the challenge, wastewater treatment technology is very sensitive towards the combination of technological equipment and incorrect operational parameters can lead to erroneous evaluation of the efficiency of individual equipment or inappropriate engineering proposals. To eliminate these risks, an analytical procedure for the selection and evaluation of parameters is proposed in this work. This procedure is demonstrated on six types of equipment. To verify the conclusions of the proposed procedure, a model design of the equipment was performed, in which the influence of individual parameters was concisely assessed. By using the data, the proposed procedure could be validated more specifically. In this work, the necessary data for the design was obtained by experimental research and extensive testing. The results confirm the practical applicability of the proposed procedure.

The aim of this work was to evaluate the phenotypic and genotypic behavior and to develop a new cultivar of pumpkin (Cucurbita moschata Dusch), with cordiform fruits and fruits with thick pulp. To obtain the S0 generation (original population), fruits were collected in production areas and they presented the following characteristics: cordiform fruits, thick pulp, orange colored pulp, fruit weight between 5 and 7 kg. Seeds were planted and the plants were selfed to produce the S1 generation. The same method was used to produce the S2 generation, followed by recombination. Means, standard error and amplitude of the generations were estimated and reduction of the values. The following parameters also were estimated: heritability, genetic variance, variance of the interaction genotype x environment, coefficient of genetic variation (CVg), coefficient of environmental variation (CVe) and the relation CVg/CVe. The high heritability values associated with the genetic variance values major the genotype x environment variance shows a not significative influence of the environment for the studied characters, which facilitate the development of new pumpkin cultivar. At the second part of this work competition assays were realized in two agriculture years, 2008 and 2009, and for the variables pulp thick, fruit width, and number of seeds the ABO-MELHOR population obtained means of 4 cm, 19.69 cm and 568.66, respectively. The genetic breeding program resulted in the development of the new pumpkin cultivar 'Tiêta'.<br>O objetivo do presente trabalho foi avaliar o comportamento fenotípico e genotípico e desenvolver uma nova cultivar de abóbora (Cucurbita moschata Dusch) com formato cordiforme e polpa espessa. Para compor a primeira geração S0 (população original) foram coletados frutos de agricultores com características de formato cordiforme, polpa espessa, coloração alaranjada escura e tamanho variando de 5 a 7 kg. Estes foram autofecundados para formar a geração S1 e o mesmo procedimento foi feito para a geração S2, seguida da recombinação. Foram estimadas as médias, desvio padrão e amplitude das gerações, onde foi observada a redução nas variáveis avaliadas. Ainda foram estimados os parâmetros herdabilidade, variância genética, variância ambiental, variância genótipo x ambiente, coeficiente de variação genética (CVg), coeficiente de variação ambiental (CVe) e a razão CVg/CVe. Os altos valores de herdabilidade associados a valores de variância genética maiores que os da interação genótipo x ambiente denotam uma influência não significativa do ambiente para os caracteres estudados, o que facilitaria o desenvolvimento de uma nova cultivar de abóbora. Na segunda parte do trabalho, realizou-se ensaios de competição de cultivares em dois anos agrícolas 2008 e 2009, sendo que para os caracteres espessura da polpa, largura do fruto e número de sementes a população ABO-MELHOR obteve-se médias de 4 cm, 19,69 cm e 568,66, respectivamente. O programa de melhoramento genético resultou no desenvolvimento da nova cultivar Tiêta de abóbora.

L'orthoptere est une eolienne non conventionnelle, a axe vertical, constituee de deux palmes type plaque plane qui restent constamment perpendiculaires entre elles. Etude experimentale et numerique de l'influence de divers parametres: grandeur de corde, calage, presence d'un axe central, et rayon de courbure des bords d'attaque, sur les performances globales de l'eolienne. Conception d'un systeme de regulation par microprocesseur. Etude theorique de couplage direct avec une pompe a chaleur

Orientador: Marines Nobre dos Santos Uchoa<br>Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba<br>Made available in DSpace on 2018-08-06T14:54:47Z (GMT). No. of bitstreams: 1 Steiner-Oliveira_Carolina_M.pdf: 2452614 bytes, checksum: cd8304b4153cd0bfcc7b167b1691f06e (MD5) Previous issue date: 2006<br>Resumo: A irradiação do esmalte dentário com laser de CO2, especialmente se associada ao flúor, pode aumentar a resistência deste substrato ao desafio ácido. Esta tese, constituída por 2 artigos, teve por objetivos: estabelecer a menor densidade de energia obtida com um laser de CO2 (À=10,6 flm) pulsado, que quando aplicada sobre o esmalte dentário humano, seja capaz de promover mudanças químicas e morfológicas e de reduzir sua suscetibilidade a ácidos, sem causar danos pulpares; avaliar, in vitro, os efeitos combinados de um laser de C02 pulsado (À=10,6 ).lm) e do dentifrício e enxaguatório fluoretados na redução da progressão de lesão de cárie artificial em esmalte dentário humano. No estudo 1, durante a irradiação de terceiros molares inclusos com densidades de energia de 1,5 a 11,5 J/cm2, foram avaliadas as alterações na temperatura pulpar através de um termopar. As modificações químicas e morfológicas da superfície do esmalte induzidas pelo laser foram determinadas, respectivamente, através de espectroscopia FT-Raman e microscopia eletrônica de varredura. Os dentes foram submetidos à ciclagem de pH e a perda mineral foi determinada através de microdureza em corte longitudinal. Os espectros Raman obtidos foram analisados pelo teste t pareado e os resultados das variáveis alteração de temperatura e microdureza, foram analisados estatisticamente pelos testes ANOV A e Tukey, todos com nível de significância fixado em 5%. No seguJ?-do estudo, espécimes de esmalte obtidos de terceiros molares inclusos foram previamente desmineralizados e em seguida aleatoriamente divididos em nove grupos tratados ou não com laser de CO2, com ou' sem dentifrício fluoretado e com ou sem enxaguatório fluoretado, fazendo todas as associações possíveis entre os tratamentos. Após a ciclagem de pH, as concentrações de flúor das soluções des e remineralizadora foram determinadas e os espécimes foram analisados, qualitativamente, por microscopia de luz polarizada e teste de microdureza em corte longitudinal para quantificar mudanças no conteúdo mineral. Os resultados foram analisados estatisticamente pelos testes ANOVA e Tukey, com nível de significância fixado em 5%. No estudo 1, as mudanças de temperatura intrapulpares não excederam 3°C para todos os grupos irradiados. A espectroscopia FT -Raman e a microscopia eletrônica de varredura indicaram que as densidades de energia iguais ou superiores a 6,0 J/cm2 foram suficientes para promover modificações químicas e morfológicas na superficie do esmalte. A redução da desmineralização do esmalte promovida pelo laser foi observada com as densidades de energia a partir de 10,0 J/cm2. No estudo 2, todos os tratamentos foram capazes de reduzir a perda mineral do esmalte, quando comparados ao grupo controle (p<0,05). Todas as terapias combinadas, exceto a associação de laser e enxaguatório, causaram remineralização do esmalte dentário. Concluindo, os resultados desses estudos indicaram que a densidade de energia do laser de C02, que pode ser aplicada sobre o esmalte dentário capaz de produzir efeito na prevenção da desmineralização sem oferecer danos para à polpa dentária, é 10,0 J/cm2 e que o laser de CO2, combinado ou não com flúor, é capaz de reduzir a progressão da desmineralização do esmalte dentário em situações de alto desafio cariogênico in vitro<br>Abstract: The irradiation of dental enamel by CO2 laser, especialIy if combined with fluoride, can increase the enamel acid resistance. Thus, this thesis, comprised by 2 manuscripts, aimed: to establish the lowest energy fluency of a pulsed 10.6 Ilm C02 laser that, when applied on enamel surface, is able to cause chemical and morphological changes and reduces its acid resistance reactivity, without causing pulpal harm; to assess, in vitro, the combined effects of a 10.6 Ilm CO2 laser, fluoridated dentifrice and fluoridated mouthrinse in the reduction of lesion progression in human carious dental enamel. In study I, during the irradiation of human teeth with 1.5-11.5J/cm2, intrapulpal thermal effects were evaluated by a thermocouple. Moreover, chemical and morphological modifications were assessed on enamel surface, through FT-Raman and MEV analysis, respectively. The teeth were submitted to a pH-cyc1ing model and the enamel mineralloss was determined by crosssectional microhardness. The.Raman spectra obtained were assessed by the paired t test and thermal and microhardness variables were analyzed by ANOV A and Tukey tests, alI with 5% of statistical significance. In study 2, slabs of previously demineralized dental enamel were randomly assigned to nine groups (n = 10) and treated withlwithout CO2 laser and withlwithout fluoridated dentifrice and withlwithout fluoridated mouthrinse, making all possible associations between these treatments. After pH-cyc1ing, fluoride concentrations were determined in the de and remineraliziRg solutions and qualitative polarized light analysis was performed. In addition, cross-sectional microhardness test was dOJ;1e to quantify changes in mineral content. In the first study, for alI irradiated groups, intrapulpal temperature changes were below 3°C. FT-Raman spectroscopy and scanning electron microscopy indicated that fluencies as low as 6.0 J/cm2 were sufficient to induce chemical and morphological changes in enamel. Laser-induced inhibitory effects on enamel demineralization were observed in fluencies of 10.0 and 11.5 J/cm2. In the second study, alI treatments were able to decrease mineralloss when compared to control group (p < 0.05). AdditionalIy, except for the association of laser with fluoridated mouthrinse, all combined treatments have caused enamel remineralization. In conclusion, the results of these studies suggest that the lowest laser fluency capable of producing chemical and morphological changes to reduce acid reactivity of enamel without exposing pulp vitality to danger is 10.0 J/cmZ and that pulsed COz laser irradiation alone or combined with fluoridated products produced an effective protection against demineralization progression in dental enamel in vitro<br>Mestrado<br>Odontopediatria<br>Mestre em Odontologia

Le travail de cette thèse porte sur l’identification et le contrôle des propriétés thermiques et acoustiques de nanostructures à fort potentiel thermoélectrique appelés « Super-réseaux ». Le manuscrit comporte trois parties : La première partie est consacrée à la description théorique des phénomènes de transport thermique par diffusion dans les solides isolants et semi-conducteurs. Nous abordons tout d’abord le point de vue atomique, puis macroscopique en utilisant la méthode des quadripôles thermiques. La fin du chapitre est consacrée aux propriétés acoustiques et thermiques des super-réseaux. La deuxième partie présente et compare les méthodes de Thermoreflectance laser synchrone et asynchrone utilisées pour extraire les propriétés thermiques de couches minces et de super-réseaux. Nous montrons que dans le cas synchrone, les signaux sont soumis à des artefacts modifiant leur allure et rendant difficile l’identification des propriétés thermiques. Dans le cas asynchrone, la suppression de tous les éléments mobiles permet d’obtenir un signal sans artéfact. Nous traitons ensuite des fonctions de sensibilité au modèle développé puis nous validons la méthode d’identification en estimant la conductivité thermique d’un film mince de SiO2. La troisième partie présente les résultats des identifications de la conductivité thermique de différents super-réseaux de SiGe. Nous montrons que les résistances d’interface jouent un rôle majeur dans l’explication de la réduction de la conductivité thermique. Nous étudions également des super-réseaux contenant des îlots de Ge, nous montrons que de telles structures permettent d’obtenir non seulement des conductivités proches de celles des matériaux amorphes, mais le comportement linéaire de la conductivité en fonction de la période montre qu’il est possible de contrôler cette dernière. Enfin, nous utilisons la Thermoreflectance pour réaliser une étude de spectroscopie THz de phonons cohérents dans les super-réseaux et nous mettons en évidence la sélectivité spectrale des ces nanostructures<br>The work presented in this thesis deals with identification and control of the thermal and acoustic properties of high thermoelectric potential nanostructures called “superlattices”. This thesis is divided in three parts: The first part gives a theoretical description of thermal diffusion in insulating and semiconducting materials. We first broach the atomic description then the macroscopic view using the Thermal Quadrupole model. The end of this chapter deals with acoustic and thermal properties specific to superlattices. The second part describes and compares synchronous and asynchronous thermoreflectance techniques used to extract thermal properties of thin films and superlattices. We find that for the synchronous case signals are subject to artifacts which confound parameter estimations. For the asynchronous case, we find that lack of a mechanical translation stage removes these artifacts. We then investigate the sensitivity functions, and finally validate our identification method by estimation of the thermal conductivity of a SiO2 thin film. The third part presents the results of thermal parameter identification in SiGe superlattices. We show that thermal interfaces play a major role to in the overall thermal conductivity. We also study superlattices with Ge nanodots and show that for such structures we are able to obtain thermal conductivity values near the amorphous values. Moreover, the linear behavior of the thermal conductivity with period thickness shows that it is possible to control this value. Finally, we use Thermoreflectance to perform THz coherent phonon spectroscopy of superlattices, revealing the spectral selectivity of these nanostructures

碩士<br>國立成功大學<br>機械工程學系碩博士班<br>93<br>The centrifugal impeller is a three-dimensional twisted surface. The energy is generated by velocity and pressure converting. The centrifugal impeller has some hard works, such as the interference of machining, the complex shape of blades, the difficulty in setting up blades and multi-axial machining, and the complicated fluid characteristics. That includes the flow simulation method and five-axial machining technology, and the related technique is also the key point of national defense industry. It is difficult and expensive to get the technique in Taiwan. Obviously, it is an important business that how to design and to analyze the performance of centrifugal pump accurately. There has many obstacles to overcome. 　　Therefore, the volume swept method based on the generated machining concept is advanced by the design of centrifugal impeller in this research. And it is discussed that how to create the profile of centrifugal impeller and machining method. The analytical spline and the rational B-spline will be introduced for the space-curve construction and curve parameters, fluid parameters, and machining parameters will be combined. Then it is found that the influence of curve on the performance of flow field. It is discussed that the fluid characteristics of tip clearance, the influence of tip clearance, and the twisted angle of impeller blades on the performance of flow field. Machining kinetic analysis of different curve is discussed in this research, and planning of tool path was worked by the concept of scallop height. At the same time, this research uses vector analysis to determine that the possibility of collision, and detects the possibility of over-cutting by the principal curvature. Finally, the performance of machining planning was estimated in this research.

碩士<br>國立高雄第一科技大學<br>機械與自動化工程所<br>93<br>The hydraulic ram pump is a kind of hydraulic power machine without any external energy. The hydraulic ram pump should be emphasized due to the “Green Concept” raised up. However, the performance of hydraulic ram pump depends highly on the construction parameters . So that we aimed the purpose of our study in finding the relationship among design parameters and variable functions. By effective experiments we adopt the Taguchi method. We select some important primary factors such as: stroke of the waste value, closed pressure of waste value, length of the drive pipe, and delivery head. To reduce the cost and obtain the maximal performance are also our important target. We have reached some results as the followings: *In general, the efficiency of the hydraulic ram pump is about 50%. However, in this study the efficiency of our pump made of P.V.C can get up to 70%. *The stroke of the waste valve and the length of the drive pipe has interacted each other. *In practice, when the water supply is more than drive flows, it is comment to choose the maximum horse power. Otherwise, the maximum efficiency was suggested.

碩士<br>國立臺灣海洋大學<br>系統工程暨造船學系<br>102<br>The thesis discusses a specific tubular pump designed for left ventricular assist device (LVAD). Such a device must be designed precisely when applied to save human being. The tubular pump is a tube winded with several coil sets outside and has a piston inside. The piston includes a permanent magnetic ring that is driven by the electromagnetic field generated by outside coil sets. This paper focuses on how to optimally design the permanent magnetic ring to promote the tubular pump performance. There are two parts: one is the optimization of magnetic ring design by parameter analysis, the other is the drog force evaluation of the magnetic ring during its reciprocation. In the paper, three key design parameters are identified and the best design is proposed through mutual association and evaluation. Moreover, a proper function of drog force coefficient is designed and proposed. The results show the proposed function of drog force coefficient properly makes the magnetic ring moving like the experimental results. At the end, this paper gives the analysis showing that the added permeability metals increase the electromagnetic force .It is suggested to add permeability metals outer instead of inner the coil sets.

碩士<br>國立中山大學<br>機械工程學系研究所<br>88<br>Turbo Molecular pumps, abbreviated as TMP, can create a high vacuum environment for some special industries, especially the semiconductor and IC industries. The turbo blade design is one of the main technologies that affect the performance of a TMP. The object of this study is to investigate what kind of blade design parameters, e.g. blade angle, blade spacing, blade chord, blade velocity, etc., will affect the performance of TMP. It is hope that an analysis methodology of these parameters can be setup in the viewpoint of pumping rate curve. The results of this study will be useful for the design of TMP.

A Pipeline Analytical Program and Dredging Knowledge{Base Expert{System (DKBES) determines a pipeline dredge's production and resulting cost and schedule. Pipeline dredge engineering presents a complex and dynamic process necessary to maintain navigable waterways. Dredge engineers use pipeline engineering and slurry transport principles to determine the production rate of a pipeline dredge system. Engineers then use cost engineering factors to determine the expense of the dredge project. Previous work in engineering incorporated an object{oriented expert{system to determine cost and scheduling of mid{rise building construction where data objects represent the fundamental elements of the construction process within the program execution. A previously developed dredge cost estimating spreadsheet program which uses hydraulic engineering and slurry transport principles determines the performance metrics of a dredge pump and pipeline system. This study focuses on combining hydraulic analysis with the functionality of an expert{system to determine the performance metrics of a dredge pump and pipeline system and its resulting schedule. Field data from the U.S. Army Corps of Engineers pipeline dredge, Goetz, and several contract daily dredge reports show how accurately the DKBES can predict pipeline dredge production. Real{time dredge instrumentation data from the Goetz compares the accuracy of the Pipeline Analytical Program to actual dredge operation. Comparison of the Pipeline Analytical Program to pipeline daily dredge reports shows how accurately the Pipeline Analytical Program can predict a dredge project's schedule over several months. Both of these comparisons determine the accuracy and validity of the Pipeline Analytical Program and DKBES as they calculate the performance metrics of the pipeline dredge project. The results of the study determined that the Pipeline Analytical Program compared closely to the Goetz eld data where only pump and pipeline hydraulics a ected the dredge production. Results from the dredge projects determined the Pipeline Analytical Program underestimated actual long{term dredge production. Study results identi ed key similarities and di erences between the DKBES and spreadsheet program in terms of cost and scheduling. The study then draws conclusions based on these ndings and o ers recommendations for further use.

To predict the behavior of municipal wastewater treatment facilities, the Activated Sludge Model No. 1 is often used. This model has also served as the basis for the development of many other models to determine the behavior of activated sludge systems treating municipal wastewater, and has also been extended to the development of a model for petrochemical activated sludge treatment systems. Application of the model requires the determination of kinetic parameters and wastewater composition using continuous culture laboratory scale activated sludge reactors. These systems are laborious to operate and are equipment intensive. Activated sludge systems are a commonly used method of secondary treatment of pulp mill effluents in British Columbia. The application of the Activated Sludge Model No. 1 has not been extended previously to predict the performance of carbon oxidation in activated sludge systems treating pulp mill effluent. The objective of this study was to establish a database of experimental information on the characteristics of activated sludge systems treating bleached Kraft pulp mill wastewater using simple on-site batch test methods. Batch test methods involving respirometry and chemical oxygen demand measurements were successful in generating a data set of wastewater and biomass characteristics comparable to those found in the literature. Development of a dynamic mechanistic model based on the data generated in this study will provide a framework for studying the behavior of pulp mill activated sludge systems and provide a basis for planning further experimentation.

Eucalyptus macarthurii is one of the cold tolerant eucalypt species grown in South Africa for pulp and paper. However, little research has been done on this species’ growth performance. A study was therefore initiated to: i) analyse growth characteristics of Eucalyptus macarthurii at two sites and to calculate genetic parameters (genetic and phenotypic correlations, heritabilities and genetic gains), ii) develop a non-destructive near infrared calibration model to predict whole tree pulp yield of Eucalyptus macarthurii, and iii) screen a second generation Eucalyptus macarthurii breeding population, using the developed near infrared calibration model on core samples, to predict screened pulp yield and to rank and identify families with superior pulping properties. Eucalyptus macarthurii population growth data (diameter under bark, diameter over bark, bark thickness, bark stripping, height, basic wood density and stem form) were measured at Pinewoods and Vlakkloof sites and their respective genetic parameters calculated. Genotype by environment interaction was found in this population, indicating that different populations should perhaps be developed independently of each other for the two sites. Genetic and phenotypic correlations between diameter over bark and diameter under bark were, 0.96 and 0.98 for Pinewoods and 0.98 and 0.99 for Vlakkloof, respectively. These correlations indicated that selection of diameter over bark would lead to a positive indirect selection for diameter under bark. The heritability estimates also ranged from 0.03 to 0.23 at both sites, which indicated a reasonable response to selection. The predicted gains for all traits found at Pinewoods were higher than those at Vlakkloof for progeny trials E76/P1, except height for progeny trial E76/P2, which was 2.09m at Pinewoods site and 3.52m at Vlakkloof site which showed that, selection for taller trees will be more effective at Vlakkloof site. A preliminary study was undertaken from eleven second generation trees (2007 tree collection) to investigate if the radial strip core taken at breast height predicts the whole tree wood properties. Correlations found between laboratory Kraft pulping of whole tree wood discs and whole tree NIR spectra with that of the radial strip core NIR spectra were 0.9472 and 0.9506, respectively. These results confirmed that NIR spectra of the radial strip core at breast height predict the whole tree wood properties. A non-destructive near infrared calibration model using wood samples was obtained from Eucalyptus macarthurii felled trees. The wood samples were chipped into wood chips, pulped using Kraft pulping (reference method) and a sub-sample of wood chips of the same trees were ground into sawdust samples and analysed through near infrared spectroscopy for screened pulp yield. The screened pulp yield values obtained from both processes had a narrow screened pulp yield range of 40 to 48%. The Eucalyptus macarthurii screened pulp yield values obtained from both processes, as well as from values obtained from other eucalypt species, were subjected to Vision® Software for calibration and validation of the near infrared calibration model. The results indicated a strong calibration correlation coefficient of 94%, between Kraft pulping and near infrared spectroscopy with a validation coefficient of 89%. The strong correlation and validation coefficient indicated that a reliable non-destructive near infrared model to predict screened pulp yield was successfully developed. The successful development of the valid calibration model required a wider range of other eucalypts species, which improved the development of the model. The developed calibration model was applied to the second generation breeding population planted in KwaZulu-Natal and Mpumalanga provinces, using wood core samples obtained from standing trees for the prediction of screened pulp yield. The highest screened pulp yield achieved was 48%, which compared well to that found for Kraft pulping, which confirmed the success of the development of the calibration model. There was a wide scope of growth variation found amongst traits, which will be useful in selecting superior trees for the next generation. The development of the nondestructive near infrared calibration model was a success due to the strong correlation coefficients found between the screened pulp yields obtained from Kraft pulping and near infrared spectroscopy processes, which was achieved by the inclusion of other eucalypt species in the dataset. The calibration model can be used to select the top performing individual and family trees for the next generation based on screened pulp yield. Tree improvement trials can now be conserved for further breeding, without felling the trees for determination of pulping properties.<br>Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2008.