O objetivo da presente pesquisa é analisar o desempenho termo-hidráulico do lado do ar de trocadores de calor tubo-aletados. Uma pesquisa da literatura foi executada em duas áreas diferentes: desempenho termo-hidráulico e seleção de superfície, feita por comparações de desempenho, para otimizar o projeto de trocadores de calor. O impulso principal da pesquisa esteve na avaliação experimental de dez serpentinas para investigar o efeito dos seguintes parâmetros sobre o desempenho do lado do ar: número de fileiras de tubos, densidade de aletas, superfície interna dos tubos e superfície da aleta (corrugada ou janelada). Os experimentos foram executados com água quente escoando internamente aos tubos em uma bancada de testes equipada com controladores que permitiram o controle exato e a medição das condições do ar e da água. As comparações com dados disponíveis na literatura para condições semelhantes revelaram que as tendências dos resultados presentes são coerentes e adequadas. Os resultados de transferência de calor e perda de carga da presente investigação não são adequadamente correlacionados por equações da literatura, sendo os desvios atribuíveis a diferenças na geometria das aletas. Finalmente, um procedimento de seleção de superfície para as aletas foi testado baseado em uma relação entre o índice de transferência de calor e a potência de bombeando. A superfície que obteve melhor desempenho entre as testadas foi a aleta janelada numa serpentina de quatro fileiras de tubos / The aim of the present research was to analyze the termo-hidraulic performance of the air side of plate-fin-and-tube heat exchangers. A literature survey has been carried out in two different areas: thermo-hidraulic performance and surface selection, done by performance comparisons, to optimize heat exchangers design. The main thrust of the research has been in the experimental evaluation of ten coils in order to investigate the effect of the following parameters over the air side performance: number of tube rows, fin density, tubes internal surface and surface fins (wavy or louvered). Experiments have been carried out with warm water as the tube fluid in a test bench with control capabilities which allowed the accurate control and measurement of air and water conditions. Comparisons with data available in the literature for similar conditions have revealed that the trends of the present results are consistent and adequate. Heat transfer and pressure drop results of the present investigation are not adequately correlated by equations from literature, deviations being attributable to differences in the geometry of the fins. Finally, a procedure for fin surface selection has been tested based on the ratio between the heat transfer rate and the pumping power. The best performing surface among the ones tested was the louver fin in a four tube row coil

Le remplacement de monomères d'origine pétrosourcée par des analogues biosourcés améliore la durabilité et diminue la dépendance aux ressources fossiles. De plus, de nouvelles caractéristiques et propriétés sont souvent découvertes. Les polyesters aliphatiques biosourcés ont déjà partiellement remplacé les produits traditionnels. Dans le contexte du projet Sorago, une résine entièrement biosourcée pour les revêtements de prélaquage des produits intérieurs a déjà été introduite sur le marché (Estetic® bio Air, Arcelor Mittal). Pour permettre l'utilisation du produit dans des applications extérieures, sa résistance à la lumière UV et à l'humidité sont à améliorer. Cela pose deux problèmes : Une disponibilité limitée de monomères pouvant introduire de la rigidité dans la résine et la relation entre la structure de la résine et sa dégradation. La vanilline a été choisie comme synthon pour la gamme des monomères rigides et biosourcées. La transformation de sa fonction aldehyde par réaction de Perkin et sa réactivité a été examinée. Dans une série des copolymerisations, l'influence des conditions de réaction sur la composition du produit final a été proposée. Une relation structure-propriétés concernant la température de la transition vitreuse et la viscoélasticité des plusieurs monomères biosourcées a été établie, et comparée avec celle des monomères petrosourcées. Une série des prototypes avec des propriétés très variées a été soumise à un test de vieillissement rapide. Leur dégradation a été suivie sur la base de leur rétention de brillance, par FTIR et par des tests de µ-dureté et d'épaisseur des films. La performance des prototypes biosourcés s'est révélée inférieure à celle d'une résine standard pétrosourcée mais aucune évidence qui suggère que cela est du à la présence des monomères biosourcées n'a été détectée. Cela suggère que la création d'une résine biosourcée et suffisamment durable pour l'extérieur sera possible / Moving away from petroleum and towards biobased materials not only leads to greater sustainability and lower dependence on diminishing fossil resources, but can also catalyse the discovery of new properties. Aliphatic polyesters based on renewable resources have already started to replace traditional products. Within the Sorago project, a fully biobased resin for interior coil coatings has recently been proposed on the market (Estetic® Bio Air, Arcelor Mittal). In order to extend the possible use of the biobased product to exterior applications, an improvement of its resistance to humidity and UV radiation is crucial. This presents two challenges: The limited availability of monomers which provide rigidity in the resin structure and the relationship between the resin composition and its weatherability. Vanillin was chosen as a possible extension to the range of rigid, biobased monomers for polyesterification reactions. The transformation of its aldehyde and its reactivity was studied in terms of catalytic activation and through a series of copolymerisations which revealed the influence of the reaction conditions on the composition of the product. A structure-property relationship concerning the coating glass transition temperature and visco-elastic behaviour of the coating was furthermore established for a series of renewable monomers and contrasted with petroleum based equivalents. Series of prototypes with a wide variety of properties were then subjected to accelerated weathering tests. Their degradation was followed directly by gloss retention and different mechanisms were revealed using FTIR, µ-hardness and film thickness measurements. While the performance of the biobased coating was subpar, no evidence linking its degradation to the presence of renewable monomers was found, suggesting that the creation of a sufficiently durable and renewable exterior coating will be possible

This thesis presents technical and methodological developments aiming tooffer a viable alternative for the treatment of digestive cancers (rectum and esophagus). Compared to the standard methods of therapy, the high intensity contact ultrasound guided by MRI is a less invasive approach. MRI offers 2 advantages: good spatial resolution, and real-time temperature control. This treatment method requires efficacy and safety. Three prototypes of RF coil integrated with ultrasound transducers were built in order to increase the spatial and temporal resolution ofthe MR images, and the accuracy of the temperature measurement. The integrated coils showed a better sensitivity compared to a standard extracorporeal coil. Anatomical (voxel 0.4x0.4x5 mm3)and thermometry (voxel 0.75x0.75x8 mm3, 2s/image) high resolution MR images were acquired in-vivo. The temperature was measured, within a radius of 20 mm from the balloon, with a standard deviation <1°C. The flow artifacts caused by the water circulating inside the cooling balloon could be shifted out of the region of interest. The temperature evolution was controlled automatically, at different depths, with one control point per beam. The controller showed a good accuracy during in-vivo experiments (standard deviation less than 5%). The phased-arrayultra sound transducer permits the successive activation of multiple beams during the same dynamic of sonication. Simulations were conducted in order to offer an optimal treatment planning for a defined tumor. A new design of ultrasound transducer with 256 elements with revolution symmetry, based on a natural geometrical focalization, was proposed.

<p>På SSAB i Borlänge har man upptäckt att avgaser från färgen förorenar ugnarna vid härdning. Avgaserna består av lösningsmedel och andra flyktiga föreningar som sedan förkolnas och faller ner på lackerade plåtband. För att komma runt det här problemet har SSAB tillsammans med Akzo Nobel Industrial Finishes AB, i Gamleby, tillverkat en färg som inte ska ge ifrån sig något lösningsmedel och på så sätt minska bildandet av föroreningar i ugnarna. Färgen heter NOVA GreenCoat och innehåller rapsmetylester, RME, som är ett reaktivt lösningsmedel och ska binda till bindemedlet i färgen och på så sätt hindras från att avgå vid härdning.</p><p>Syftet har varit att undersöka om en viss metod fungerar bra för att samla upp avgaser vid härdning. Avgaserna analyserades med GC-MS och härdningen studerades med FTIR. Arbetet har utförts både i Borlänge och i Gamleby.</p><p>Metoden för uppsamling av avgaserna visade sig fungera, dock inte särskilt effektivt. Den skulle därför behöva optimeras.</p><p>Härdningen kunde till viss del följas med hjälp av FTIR. Förändring i IR-spektrumet syntes för hydroxyltoppen vid cirka 3500 cm^-1. En skillnad kunde ses för en topp vid 2858 cm^-1 som uppkom i det ohärdade materialet innehållande RME, men den försvann under härdning. Toppen ökade med ökad mängd RME och syntes inte alls för de prover som inte innehöll RME.</p><p>Samtliga gjorda analyser indikerade att RME avgick vid härdning. Vid analys med GC-MS kunde de föreningar som avgick från RME identifieras som: metyl-14-metyl pentadekanoat och/eller metyl hexadekanoat, olika former av metyl oktadekanoat samt olika former av metyl eikosanoat. Andra föreningar från klarlacken som avgick var lösningsmedel x och y samt i två av proverna hexametoximetylmelamin, HMMM.</p> / <p>Problems with exhaust gases from paint that contaminates the ovens have been discovered at SSAB in Borlänge.  The exhaust gases contain solvents and other volatiles that vaporize from the paint and later on carbonize and fall down on the next coming sheets. SSAB and Akzo Nobel Industrial Finishes AB have developed a paint that is not supposed to vaporize any solvents and therefore reduce the contaminations of the ovens. The paint is called NOVA GreenCoat and contains rapeseed methyl ester, RME. RME is a reactive solvent that is supposed to react with the binder in the paint and therefore be prevented from leaving during thermal cure.</p><p>The purpose was to investigate whether a specific method worked well, for collecting the exhaust gases during thermal cure, or not. The collected exhaust gases were analyzed by using GC-MS and the cure was studied with FTIR. The work was executed both in Borlänge and Gamleby.</p><p>The method for collecting the exhaust gases worked, unfortunately it wasn’t particularly effective. It therefore needs to be optimized.</p><p>The cure could partially be studied by using FTIR. Changes in the IR-spectrum could be followed by looking at the hydroxyl peak at approximately 3500 cm^-1. A certain difference was observed for a peak at 2858 cm^-1 that appeared in the uncured material containing RME. The peak disappeared during cure. It increased with increased amount of RME and could not be observed at all for the samples that did not contain RME.</p><p>All the analyzed samples indicated that RME vaporize during cure. When analyzed with GC-MS the volatiles that vaporize from RME were identified as: hexadecanoic acid methyl ester and/or penta decanoic acid methyl-14-methyl ester, different forms of octadecanoic acid methyl ester and different forms of eicosanoic acid methyl ester. Other volatiles that vaporize from NOVA GreenCoat were solvent x and solvent y and for two of the samples hexa metoxy methyl melamine, HMMM, was also found.</p>

A wave energy converter has been constructed and its function and operational characteristics have been thoroughly investigated and published. The wave energy converter was installed in March of 2006 approximately two kilometers off the Swedish west coast in the proximity of the town Lysekil. Since then the converter has been submerged at the research site for over two and a half years and in operation during three time periods for a total of 12 months, the latest being during five months of 2008. Throughout this time the generated electricity has been transmitted to shore and operational data has been recorded. The wave energy converter and its connected electrical system has been continually upgraded and each of the three operational periods have investigated more advanced stages in the progression toward grid connection. The wave energy system has faced the challenges of the ocean and initial results and insights have been reached, most important being that the overall wave energy concept has been verified. Experiments have shown that slowly varying power generation from ocean waves is possible. Apart from the wave energy converter, three shorter studies have been performed. A sensor was designed for measuring the air gap width of the linear generator used in the wave energy converter. The sensor consists of an etched coil, a search coil, that functions passively through induction. Theory and experiment showed good agreement. The Swedish west coast wave climate has been studied in detail. The study used eight years of wave data from 13 sites in the Skagerrak and Kattegatt, and data from a wave measurement buoy located at the wave energy research site. The study resulted in scatter diagrams, hundred year extreme wave estimations, and a mapping of the energy flux in the area. The average energy flux was found to be approximately 5.2 kW/m in the offshore Skagerrak, 2.8 kW/m in the near shore Skagerrak, and 2.4 kW/m in the Kattegat. A method for evaluating renewable energy technologies in terms of economy and engineering solutions has been investigated. The match between the technologies and the fundamental physics of renewable energy sources can be given in terms of the technology’s utilization. It is argued that engineers should strive for a high utilization if competitive technologies are to be developed.

På SSAB i Borlänge har man upptäckt att avgaser från färgen förorenar ugnarna vid härdning. Avgaserna består av lösningsmedel och andra flyktiga föreningar som sedan förkolnas och faller ner på lackerade plåtband. För att komma runt det här problemet har SSAB tillsammans med Akzo Nobel Industrial Finishes AB, i Gamleby, tillverkat en färg som inte ska ge ifrån sig något lösningsmedel och på så sätt minska bildandet av föroreningar i ugnarna. Färgen heter NOVA GreenCoat och innehåller rapsmetylester, RME, som är ett reaktivt lösningsmedel och ska binda till bindemedlet i färgen och på så sätt hindras från att avgå vid härdning. Syftet har varit att undersöka om en viss metod fungerar bra för att samla upp avgaser vid härdning. Avgaserna analyserades med GC-MS och härdningen studerades med FTIR. Arbetet har utförts både i Borlänge och i Gamleby. Metoden för uppsamling av avgaserna visade sig fungera, dock inte särskilt effektivt. Den skulle därför behöva optimeras. Härdningen kunde till viss del följas med hjälp av FTIR. Förändring i IR-spektrumet syntes för hydroxyltoppen vid cirka 3500 cm-1. En skillnad kunde ses för en topp vid 2858 cm-1 som uppkom i det ohärdade materialet innehållande RME, men den försvann under härdning. Toppen ökade med ökad mängd RME och syntes inte alls för de prover som inte innehöll RME. Samtliga gjorda analyser indikerade att RME avgick vid härdning. Vid analys med GC-MS kunde de föreningar som avgick från RME identifieras som: metyl-14-metyl pentadekanoat och/eller metyl hexadekanoat, olika former av metyl oktadekanoat samt olika former av metyl eikosanoat. Andra föreningar från klarlacken som avgick var lösningsmedel x och y samt i två av proverna hexametoximetylmelamin, HMMM. / Problems with exhaust gases from paint that contaminates the ovens have been discovered at SSAB in Borlänge.  The exhaust gases contain solvents and other volatiles that vaporize from the paint and later on carbonize and fall down on the next coming sheets. SSAB and Akzo Nobel Industrial Finishes AB have developed a paint that is not supposed to vaporize any solvents and therefore reduce the contaminations of the ovens. The paint is called NOVA GreenCoat and contains rapeseed methyl ester, RME. RME is a reactive solvent that is supposed to react with the binder in the paint and therefore be prevented from leaving during thermal cure. The purpose was to investigate whether a specific method worked well, for collecting the exhaust gases during thermal cure, or not. The collected exhaust gases were analyzed by using GC-MS and the cure was studied with FTIR. The work was executed both in Borlänge and Gamleby. The method for collecting the exhaust gases worked, unfortunately it wasn’t particularly effective. It therefore needs to be optimized. The cure could partially be studied by using FTIR. Changes in the IR-spectrum could be followed by looking at the hydroxyl peak at approximately 3500 cm-1. A certain difference was observed for a peak at 2858 cm-1 that appeared in the uncured material containing RME. The peak disappeared during cure. It increased with increased amount of RME and could not be observed at all for the samples that did not contain RME. All the analyzed samples indicated that RME vaporize during cure. When analyzed with GC-MS the volatiles that vaporize from RME were identified as: hexadecanoic acid methyl ester and/or penta decanoic acid methyl-14-methyl ester, different forms of octadecanoic acid methyl ester and different forms of eicosanoic acid methyl ester. Other volatiles that vaporize from NOVA GreenCoat were solvent x and solvent y and for two of the samples hexa metoxy methyl melamine, HMMM, was also found.

An intracranial aneurysm can be a serious, life-threatening condition which may go undetected until the aneurysm ruptures causing hemorrhaging within the brain. The typical treatment method for large aneurysms is by embolization using platinum coils. However, in about 15% of the cases treated by platinum coils, the aneurysm eventually re-opens. The solution to the problem of aneurysm recurrence may be to develop more bio-active materials, including certain polymers, to use as coil implants. In this research, a shape memory polymer (SMP) was investigated as a potential candidate for aneurysm coils. The benefit of a shape memory polymer is that a small diameter fiber can be fed through a micro-catheter and then change its shape into a three-dimensional configuration when heated to body temperature. The SMP was tested to determine its thermo-mechanical properties and the strength of the shape recovery force. In addition, composite specimens containing tantalum filler were produced and tested to determine the mechanical effect of adding this radio-opaque metal. Thermo-mechanical testing showed that the material exhibited a shape recovery force a few degrees above Tg. The effects of the metal filler were small and included depression of Tg and recovery force. SMP coils deployed inside a simulated aneurysm model demonstrated that typical hemodynamic forces would not hinder the shape recovery process. The x-ray absorption capability the tantalum-filled material was characterized using x-ray diffractometry and clinical fluoroscopy. Diffractometry revealed that x-ray absorption increased with tantalum concentration, however, not as the rule of mixtures would predict. Fluoroscopic imaging of the composite coils in a clinical setting verified the radio-opacity of the material.

Abstract Recently, the expansion in power system capacities leads to the development of large-scale steam turbine generator units. As a result, a fault on the power system may induce large fault current and give rise to serious torque vibrations on turbine shafts and blades, which ought to be improved in order for the reliable operation of a turbine-generator system. In the thesis, countermeasures are proposed from electrical viewing-point and from mechanical viewing-point respectively. Based on electrical viewing-point, the apparatus in the generator stator side and in the rotor side respectively is applied to suppress the induced disturbing source. The high temperature superconductive fault current limiter bank introduces a large normal-state resistance to restrict the dc component of stator fault current. The choke coil acts as a low pass filter to restrict the system-frequency component of field fault current. Both of them lead to the reduction in electromagnetic torque of system-frequency and effectively improve the vibrating behavior of blades. Based on mechanical viewing-point, it is found from the electromechanical analysis that the Generator/LP-Turbine shaft stiffness and the Generator rotor inertia constant determine the responses of all turbine blades. Once the stiffness on this shaft section is reduced by replacing the rigid shaft coupling with a flexible one or the inertia constant is augmented by a system-frequency mechanical filter, the blades become intrinsically less responsive to electrical disturbances. As a result, the blades will bear less stress impact and can be designed with smaller safety factor. On the other hand, LP-turbine long blades operated in corrosive environment and underwent the statistical stress impact due to randomly distributed negative sequence current is studied also. In such situation, the blades may be subjected to corrosion fatigue and the long term effects of power system unbalance may become the cause of fatigue damage on blades though the negative sequence current is still within the limitation of generator thermo-rating. As a result, turbine blades are possibly unprotected by traditional system unbalance protection scheme. Therefore, it will depend on the operating environments and the blade materials whether such long-term stress can be neglected or not. If there is the potential of blade damage, one has to reconsider the I2 protection settings and rearrange the load distribution to limit the system unbalance.

The thesis describes development and application of coupled resonant coil sensors, which is of growing interest for remote monitoring applications. An interrogation technique, which improves the accuracy and interrogation range of coupled resonant coil sensors, is introduced. The method uses time-domain gating to produce measurements that are dominated by the response of the sensor coil and are immune to surrounding object interference. For application in structural health monitoring a low cost embeddable coupled coil sensor, which is able to monitor the corrosion potential of reinforcement steel is presented. Results of an accelerated corrosion test using the sensor indicate that corrosion potential can be monitored with a resolution less than 10 mV and a sensitivity of 0.76 kHz/mV. The last part describes a coupled-coil pH sensor based on pH electrode potential measurement. A linear response over a 4 to 10 pH dynamic range and 50 kHz/pH sensitivity are achieved with a 0.1 pH resolution and 30 s response time.

This thesis purposes and develops inductively coupled LC (inductive-capacitive) pH sensors based on pH-sensitive electrode pair. The LC resonator circuit is based on a varactor and measures the low frequency potential difference. For wireless pH monitoring, the resonator circuit is integrated with a pH-sensitive electrode pair. This sensor demonstrates a linear response over 2 to 12 pH dynamic range, 0.1 pH accuracy and long-term stability. Accurate measurement of pH using electrode-based sensors is affected by temperature variation. A technique of simultaneously measuring two parameters, pH and temperature, with a single RLC resonator based sensor is presented. An algorithm is developed, which applies both pH and temperature measurement to incorporate temperature compensation in pH measurement. For in-fluid applications, an encapsulation method is applied to the LC resonator based sensor to reduce the influence of medium permittivity and conductivity on the sensor measurement. Non-invasive way to obtain reliable pH information from bacterial culture bioprocesses is demonstrated with the fluid embeddable sensor. The pH sensor is remodeled to an acidic and basic volatile sensor by embedding the electrodes in a hydrogel host electrolyte. Tests demonstrate that the volatile sensor has a detection limit of 1.5 ppm and 2 ppm for ammonia and acetic acid vapor, respectively. Application of the volatile sensor to fish spoilage monitoring shows that the sensor is capable of detecting the product rejection level with good sensitivity in real-time. It is important to develop low cost wireless passive pH sensor technologies for embedded applications such as bioprocess and food spoilage monitoring. The electrode-based passive LC sensor approach employed in this thesis overcomes drawbacks of some of the early developed passive pH sensors and can lead to an inexpensive implementation using printed electronics technology.