Des bulles micrométriques sont utilisées dans divers domaines, notamment dans des applications médicales basées sur les ultrasons. Il est possible d’exploiter différents effets des bulles, comme par exemple leur résonance acoustique ou leur effet destructeur en cavitation inertielle. Un autre mécanisme exploitable est la génération de micro-écoulements, appelé microstreaming, induits autour d’une bulle. Ces écoulements sont relativement lents par rapport aux oscillations rapides de la bulle. Le microstreaming et les contraintes de cisaillement associées jouent un rôle important dans la perméabilisation d’une membrane cellulaire, mais il manque encore une compréhension détaillée de l’écoulement induit. Afin d’améliorer la compréhension des phénomènes physiques, ce travail se concentre sur les écoulements induits autour d’une bulle d’air dans piégée et excitée acoustiquement dans de l’eau et oscillante en modes de surface. La partie expérimentale se décompose de deux étapes. Dans un premier temps, il est nécessaire de contrôler la dynamique de la bulle, en particulier ses modes de surface et son orientation. Ceci est réalisé par coalescence entre deux bulles. Dans un second temps, le microstreaming est généré et enregistré simultanément à la dynamique de bulle. De cette manière il est possible de corréler les motifs d'écoulement aux oscillations de la bulle. Le grand nombre de motifs obtenus peut être classé selon le mode dominant et la taille de la bulle. Une étude plus détaillée de la dynamique de bulle permet de déduire les paramètres importants qui mènent à une telle variété de motifs de microstreaming. Afin de confirmer les résultats expérimentaux, un modèle analytique a été développé. Il est basé sur les équations de la mécanique des fluides de deuxième ordre et moyennées en temps, la dynamique d'interface de la bulle obtenue expérimentalement sert de donnée d’entrée au modèle. Ce manuscrit contient en supplément une section sur la génération de microjets par l'implosion d'agents de contraste. Ces jets peuvent apparaître en cas d’excitation acoustique suffisamment élevée. L’impact de ces jets sur parois présente un autre mécanisme responsable de la perméabilisation de membranes cellulaires. / Microbubbles find use in several domains, one of them being medical ultrasound applications. Different characteristics of those bubbles such as their acoustic resonance or their destructive effect during inertial cavitation can be exploited. Another phenomenon induced around acoustically excited bubbles is microstreaming, that means a relatively slow mean flow with respect to the fast bubble oscillations. Microstreaming and its associated shear stresses are commonly agreed to play a role in the permeabilization of cell membranes, a detailed understanding of the induced flows is however missing. To acquire basic physical knowledge, this work focuses on the characterization of streaming induced around an air bubble in water, more precisely around a single acoustically trapped and excited, nonspherically oscillating bubble. The experimental part consists of two steps. First, the bubble dynamics, in particular the triggered shape mode and the orientation of the bubble have to be controlled. For this, the use of bubble coalescence proves to be an adequate method. In a second step, the microstreaming is recorded in parallel to bubble dynamics. This allows to correlate the obtained streaming patterns to the respective shape oscillations. The large number of obtained pattern types can be classified, in particular with respect to the mode number and bubble size. A close investigation of the bubble dynamics allows furthermore deducing the important physical mechanisms which lead to such a variety of streaming patterns. In order to confirm the experimental findings, an analytical model has been developed. It is based upon time-averaged second-order fluid mechanics equations and the experimentally obtained bubble dynamics serves as input parameters. Supplementary to the microstreaming work, this manuscript contains a short section on directed jetting of contrast agent microbubbles, which might appear at high acoustic driving. The impact of those microjets on cell membranes presents another mechanism made responsible for the permeabilization of cell membranes.

No description available.

Inkjet printing (jetting) technology, due to its high speed of operation and accuracy, is utilised in Additive Manufacturing (AM) of three dimensional parts. Commercially available AM processes that use jetting technology include three dimensional printing (3DP by Z-Corporation), Polyjet (by Objet), Multi Jet Modelling (MJM by 3D Systems) and three dimensional printing by Solidscape. Apart from 3D Printing by Z-corporation, all the other jetting based processes require a support material to successfully build a part. The support material provides a base to facilitate the removal of the part from the build platform and it helps manufacturing of cavities, holes and overhanging features. These support materials present challenges in terms of their removability and reusability. This research is therefore, aimed towards finding a support material composition that can be used with jetting based AM processes. The support material should be easily removable either by melting or by dissolution and also, if possible, it should be reusable. AM processes often process materials with poor mechanical properties and therefore, the parts produced by these processes have limited functionality. In an attempt to obtain complex shaped, functional parts made of nylon (i.e. Polyamide 6), a new jetting based AM process is under research at Loughborough University. The process uses two different mixtures of caprolactam (i.e. the monomer used to produce polyamide). These mixtures are to be jetted using inkjet heads and subsequently polymerised into polyamide 6. Therefore, another aim of this research was to consider the support material s suitability for jetting of caprolactam. Two different polymers were researched which included Pluronic F-127 and methylcellulose (MC). Both these polymers are known for gel formation upon heating in aqueous solutions. Due to the inhibition of polymerisation of polyamide 6 by the presence of water, non-aqueous solvents such as ethylene glycol, propylene glycol and butylene glycol were studied. Since both F-127 and MC in the glycols mentioned above had not been studied before, all the compositions prepared and investigated in this report were novel. F-127 did not show gel formation in propylene and butylene glycol but formed a gel in ethylene glycol at a concentration of 25% (w/w) F-127. MC, on the other hand, showed gel formation upon cooling in all the three glycols at concentrations as low as 5% for ethylene glycol and 1% for both propylene and butylene glycol. These compositions were characterized using experimental techniques such as Fourier Transform Infrared (FTIR) spectroscopy, hot stage microscopy, differential scanning calorimetry (DSC) and X-ray diffraction (XRD). A mechanism of gelation for both F-127 and MC in glycols is presented based on the results of these characterisation techniques. Viscosity and surface tension measurements along with the texture analysis of selected compositions were also performed to evaluate their suitability for jetting. All these compositions, due to their water solubility and/or low melting temperatures (i.e. near 500C) present the advantage of ease of removal. Removal by melting at low temperatures can also provide reusability of these support materials and thus advantages such as reduction in build cost and environmental effect can be achieved.

The main aim of this project was to investigate the possibility of manufacturing 3D parts of polyamide (nylon or PA) 6 by inkjetting its monomer caprolactam (CL). The principle of this process was similar to the other rapid prototype (RP) and rapid manufacturing (RM) processes in which a 3D part is manufactured by layer on layer deposition of material. PA6 was used as the thermoplastic polymer in this work because of its good properties and also because PA6 can be produced by heating its monomer (i.e. plus catalyst and activator) in a short time. Two polymerisation mixtures of CL-catalyst (mixture A) and CL-activator (mixture B) are intended to be jetted separately using conventional jetting heads and polymerise shortly after heating. Anionic polymerisation of CL (APCL) was investigated in the bulk and on a smaller scale. Sodium caprolactamate (CLNa and C10) and caprolactam magnesium bromide (CLMgBr) were used as catalysts and N-acetylcaprolactam (ACL) and a di-functional activator (C20) were used as activators. The influence of polymerisation conditions was investigated and optimised. These were catalyst-activator concentration, polymerisation temperature and the influence of the polymerisation atmosphere. The physical properties (monomer conversion, crystallinity, and viscosity average molecular weight) of PA6 samples produced using each catalyst-activator combinations were measured and compared. Small scale polymerisation was carried out using a hotplate, by hot stage microscopy and using differential scanning calorimetry (DSC). The influence of heating strategy on small scale polymerisation was studied using DSC. The polymerisation mixture compositions were characterised using rheometry, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and optical microscopy to investigate their suitability in jetting for using the available jetting heads. It was shown that the combination of CLMgBr-ACL resulted in fast polymerisation which was not sensitive to moisture. The C10-C20 combination resulted in fast polymerisation with the best properties in a protected environment (nitrogen); however, the polymerisation was affected by moisture in air and the properties of polymer produced and rate of polymerisation decreased in air. Polymers produced using CLNa-ACL had the poorest properties and polymerisation did not occur in air. Material characterisation showed that micro-crystals of CLMgBr existed in CLMgBr-CL mixture at the jetting temperature (80oC) which were too large to be jetted. However, the mixture of C10 in CL could be partially jetted. The activator mixtures had similar properties to CL and were easily jetted. Drop on drop polymerisation was carried out by dripping droplets of mixtures A and B (at 80oC) on top of each other on a hotplate at the polymerisation temperature. Small scale polymerisation in a DSC showed that the monomer conversion increased with increase in polymerisation temperature from 140oC to 180oC and decreased from 180oC to 200oC. The crystallinity of the polymer produced in the DSC decreased with increase in polymerisation temperature. Hot stage microscopy produced evidence for simultaneous polymerisation and crystallisation processes on heating. Small scale polymerisation in an oven and analysed by DSC showed that increasing catalystactivator concentration resulted in increasing monomer conversion and decrease in crystallinity. Monomer conversion also increased with increase in polymerisation temperature and polymerisation time. Comparison between small scale and bulk polymerisations shows a good agreement between the two polymerisation rates. This shows that the polymerisation mechanism did not change significantly when the quantity of materials was reduced to less than 20mg. Finally, the polymerisation was carried out in a DSC after jetting C10-CL and C20-CL mixtures into a DSC pan using a jetting system, which was made in another work.

A recente descoberta das reservas de petróleo do Pré-Sal no Brasil obrigou a indústria a enfrentar condições de extração adversas, a mais de 1000m de lâmina de água e 5000m de sedimentos. Com o aumento da procura, justificou-se investir em pesquisa e tecnologia para dar resposta aos diversos problemas de exploração em águas ultra profundas. Em condições desfavoráveis de exploração, diversos sistemas tecnológicos submersos autônomos no fundo do mar, nearshore e offshore, tem que ser instalados para resistir a esforços solicitados por plataformas devido a manobras de navios, ondas, correntes marinhas, ventos, etc.. Atualmente a Petrobras utiliza um sistema desenvolvido e patenteado, as estacas torpedo metálicas, para resistir às solicitações e ancorar no leito oceânico as suas plataformas flutuantes. Sua instalação consiste na queda livre e penetração no solo argiloso marinho, por ação da aceleração da gravidade nas suas massas, e que apresenta ainda alguns desafios na instalação. O presente trabalho avalia uma nova técnica de instalação de âncoras para plataformas marítimas de petróleo e outras estruturas, que serve de alternativa e/ou melhoria à técnica já utilizada, e que consiste na instalação de uma haste metálica pela ação do seu peso próprio e por aplicação de jatos de água verticais, provenientes de tubos metálicos inseridos em solos argilosos. O estudo, na primeira etapa descrita nesta tese, concentra-se em modelos reduzidos, seguindo as leis de semelhança pelo número de Froude, e futuramente pretende-se transitar para o protótipo. Os ensaios de hidrojateamento foram realizados em laboratório, utilizando tanques em forma de paralelepípedo, com paredes em acrílico, preenchidos com solo argiloso. O estudo foi realizado em modelos reduzidos para duas escalas de comprimento, correspondentes a 1:67 e 1:76, com o objetivo de estudar o mecanismo de penetração dos torpedos metálicos e nos fenômenos de hidrojateamento em solo argiloso. O solo foi caracterizado e nos ensaios foram identificados e avaliados: (a) a influência do fluxo de água a partir das variáveis vazão, pressão, velocidade e diâmetro do jato, (b) a influência da massa e diâmetro das hastes metálicas e (c) a interação solo-estaca pós instalação. Os resultados apresentados indicaram que as maiores profundidades de penetração das estacas torpedo foram atingidas para os modelos de maior massa, e também para as maiores vazões do fluxo de água, para maiores pressões de fluxo de água e menor resistência não drenada do solo. Com base nas variáveis controladas foi possível estabelecer um modelo e uma equação para estimar a profundidade máxima atingida por estacas metálicas instaladas por fluidização. Estes resultados complementaram estudos anteriores e permitiram uma avaliação, baseada em modelos reduzidos, na eficiência do jateamento, parâmetros de controle do mecanismo de erosão, profundidade máxima de penetração no leito marinho e capacidade de carga das estacas, sempre utilizando conceitos de similaridade para relacionar modelo e protótipo. / Deep water oil fields discovered by Petrobras in Brazil in 2006 brought new challenges to the offshore industry. Thus, for exploring these basins, research and technology investments are necessary to ensure production conditions, which require development of technological foundation systems, nearshore and offshore. Petrobras designed and patented an anchoring system, the torpedo pile, which serves as foundation to various types of production structures in ultra-deepwater. Torpedo is a steel pile, filled with ballast, having a cone-shaped tip. The anchor installation consists in the free fall of the torpedo from a designated height above the seafloor, which dynamically penetrates into marine clay by the action of gravity acceleration of the torpedo mass. This thesis presents an alternative installation technique for torpedo anchors based on tests carried out in reduced physical models following the law of similarity by the Froude number. The goal was to install model piles by applying downward vertical water jets. The water jetting tests were performed in the laboratory using parallelepiped-shaped tanks with acrylic walls, filled with clayey soil. The study was conducted on reduced scale models for two length scales, corresponding to 1:67 and 1:76, with the aim of studying the penetration mechanism of metal torpedoes and water jetting phenomena in clayey soil. The soil was characterized and tests were performed to identify and evaluated: (a) the influence of water flow, pressure, penetration rate and diameter of the jet, (b) the influence of the mass and diameter of the metal rods and (c) soil-pile interaction after installation. The results presented indicated that the greatest depth of penetration of torpedo piles was achieved for higher mass models, also for the higher flow rates, the Reynolds number, higher water flow pressures and lower undrained resistance of the soil. Based on these variables it was possible to establish a model and an equation to estimate the maximum depth of penetration of metal piles installed by fluidization. These results complement previous studies and allowed an assessment based on reduced models, the jetting efficiency, the control parameters of the erosion mechanism, the maximum penetration depth on the seabed and load capacity of the piles, always using concepts of similarity to relate model and prototype.

ITC/USA 2012 Conference Proceedings / The Forty-Eighth Annual International Telemetering Conference and Technical Exhibition / October 22-25, 2012 / Town and Country Resort & Convention Center, San Diego, California / A broadband passive direction finding system utilizing Luneburg lens has been investigated. With the simulated power level distribution at the detectors mounted on a Luneburg lens, both Cramér-Rao bound (CRB) and the root mean square error (RMS) based on the Correlation Algorithm (CA) for the direction of arrival (DoA) estimation have been derived and calculated. Guidelines on how to design the Luneburg lens detecting system have been studied. Finally, as a proof-of-concept demonstration, the DoA performance of a Luneburg lens fabricated using the polymer jetting technology with five detectors 10° equally spaced to receive the azimuth signal from -20° to 20° is demonstrated.

Projektet gick ut på att montera ihop en Binder Jetting 3D-skrivare som är en delav ett större projekt med syfte att framställa individanpassade läkemedel inomsjukvården. Skrivaren fungerar genom att om vartannat applicera tunna skiktpulver och bindemedel. Under konstruktionen av skrivaren tillverkades ett Boost-Demultiplexer kretskort, skrivarens chassi monterades; varpå bland annat axlar,matarkolvar och byggkolvar, spridare och motorer fästes. Slutligen drogselektronik mellan de olika komponenterna och inställningar gjordes i både firmwareoch mjukvara. För att testa skrivaren skrevs en kalibreringskub med måtten 20x20x20 mm ut,först utan pulver på ett pappersark för att avgöra om skrivarhuvudets rörelse varkorrekt, sedan i 3D med gips i pulverform och skrivarbläck som bindemedel. Frånutskriften på papper framgick det att skrivarhuvudet rör sig som önskat, däremothöll inte 3D-utskriften ihop. Detta förklaras med att bläcket inte band ihop gipsettillräckligt bra. Dock bekräftades att både matarsystemet och skrivytan rör sig somtänkt, eftersom skrivytan rört sig nedåt lika långt som utskriften krävde. Med ettlämpligare bindningsmedel antas därför skrivaren vara fullt funktionell, även omingen konkret slutsats kan dras från testutskrifterna.

A recente descoberta das reservas de petróleo do Pré-Sal no Brasil obrigou a indústria a enfrentar condições de extração adversas, a mais de 1000m de lâmina de água e 5000m de sedimentos. Com o aumento da procura, justificou-se investir em pesquisa e tecnologia para dar resposta aos diversos problemas de exploração em águas ultra profundas. Em condições desfavoráveis de exploração, diversos sistemas tecnológicos submersos autônomos no fundo do mar, nearshore e offshore, tem que ser instalados para resistir a esforços solicitados por plataformas devido a manobras de navios, ondas, correntes marinhas, ventos, etc.. Atualmente a Petrobras utiliza um sistema desenvolvido e patenteado, as estacas torpedo metálicas, para resistir às solicitações e ancorar no leito oceânico as suas plataformas flutuantes. Sua instalação consiste na queda livre e penetração no solo argiloso marinho, por ação da aceleração da gravidade nas suas massas, e que apresenta ainda alguns desafios na instalação. O presente trabalho avalia uma nova técnica de instalação de âncoras para plataformas marítimas de petróleo e outras estruturas, que serve de alternativa e/ou melhoria à técnica já utilizada, e que consiste na instalação de uma haste metálica pela ação do seu peso próprio e por aplicação de jatos de água verticais, provenientes de tubos metálicos inseridos em solos argilosos. O estudo, na primeira etapa descrita nesta tese, concentra-se em modelos reduzidos, seguindo as leis de semelhança pelo número de Froude, e futuramente pretende-se transitar para o protótipo. Os ensaios de hidrojateamento foram realizados em laboratório, utilizando tanques em forma de paralelepípedo, com paredes em acrílico, preenchidos com solo argiloso. O estudo foi realizado em modelos reduzidos para duas escalas de comprimento, correspondentes a 1:67 e 1:76, com o objetivo de estudar o mecanismo de penetração dos torpedos metálicos e nos fenômenos de hidrojateamento em solo argiloso. O solo foi caracterizado e nos ensaios foram identificados e avaliados: (a) a influência do fluxo de água a partir das variáveis vazão, pressão, velocidade e diâmetro do jato, (b) a influência da massa e diâmetro das hastes metálicas e (c) a interação solo-estaca pós instalação. Os resultados apresentados indicaram que as maiores profundidades de penetração das estacas torpedo foram atingidas para os modelos de maior massa, e também para as maiores vazões do fluxo de água, para maiores pressões de fluxo de água e menor resistência não drenada do solo. Com base nas variáveis controladas foi possível estabelecer um modelo e uma equação para estimar a profundidade máxima atingida por estacas metálicas instaladas por fluidização. Estes resultados complementaram estudos anteriores e permitiram uma avaliação, baseada em modelos reduzidos, na eficiência do jateamento, parâmetros de controle do mecanismo de erosão, profundidade máxima de penetração no leito marinho e capacidade de carga das estacas, sempre utilizando conceitos de similaridade para relacionar modelo e protótipo. / Deep water oil fields discovered by Petrobras in Brazil in 2006 brought new challenges to the offshore industry. Thus, for exploring these basins, research and technology investments are necessary to ensure production conditions, which require development of technological foundation systems, nearshore and offshore. Petrobras designed and patented an anchoring system, the torpedo pile, which serves as foundation to various types of production structures in ultra-deepwater. Torpedo is a steel pile, filled with ballast, having a cone-shaped tip. The anchor installation consists in the free fall of the torpedo from a designated height above the seafloor, which dynamically penetrates into marine clay by the action of gravity acceleration of the torpedo mass. This thesis presents an alternative installation technique for torpedo anchors based on tests carried out in reduced physical models following the law of similarity by the Froude number. The goal was to install model piles by applying downward vertical water jets. The water jetting tests were performed in the laboratory using parallelepiped-shaped tanks with acrylic walls, filled with clayey soil. The study was conducted on reduced scale models for two length scales, corresponding to 1:67 and 1:76, with the aim of studying the penetration mechanism of metal torpedoes and water jetting phenomena in clayey soil. The soil was characterized and tests were performed to identify and evaluated: (a) the influence of water flow, pressure, penetration rate and diameter of the jet, (b) the influence of the mass and diameter of the metal rods and (c) soil-pile interaction after installation. The results presented indicated that the greatest depth of penetration of torpedo piles was achieved for higher mass models, also for the higher flow rates, the Reynolds number, higher water flow pressures and lower undrained resistance of the soil. Based on these variables it was possible to establish a model and an equation to estimate the maximum depth of penetration of metal piles installed by fluidization. These results complement previous studies and allowed an assessment based on reduced models, the jetting efficiency, the control parameters of the erosion mechanism, the maximum penetration depth on the seabed and load capacity of the piles, always using concepts of similarity to relate model and prototype.

A recente descoberta das reservas de petróleo do Pré-Sal no Brasil obrigou a indústria a enfrentar condições de extração adversas, a mais de 1000m de lâmina de água e 5000m de sedimentos. Com o aumento da procura, justificou-se investir em pesquisa e tecnologia para dar resposta aos diversos problemas de exploração em águas ultra profundas. Em condições desfavoráveis de exploração, diversos sistemas tecnológicos submersos autônomos no fundo do mar, nearshore e offshore, tem que ser instalados para resistir a esforços solicitados por plataformas devido a manobras de navios, ondas, correntes marinhas, ventos, etc.. Atualmente a Petrobras utiliza um sistema desenvolvido e patenteado, as estacas torpedo metálicas, para resistir às solicitações e ancorar no leito oceânico as suas plataformas flutuantes. Sua instalação consiste na queda livre e penetração no solo argiloso marinho, por ação da aceleração da gravidade nas suas massas, e que apresenta ainda alguns desafios na instalação. O presente trabalho avalia uma nova técnica de instalação de âncoras para plataformas marítimas de petróleo e outras estruturas, que serve de alternativa e/ou melhoria à técnica já utilizada, e que consiste na instalação de uma haste metálica pela ação do seu peso próprio e por aplicação de jatos de água verticais, provenientes de tubos metálicos inseridos em solos argilosos. O estudo, na primeira etapa descrita nesta tese, concentra-se em modelos reduzidos, seguindo as leis de semelhança pelo número de Froude, e futuramente pretende-se transitar para o protótipo. Os ensaios de hidrojateamento foram realizados em laboratório, utilizando tanques em forma de paralelepípedo, com paredes em acrílico, preenchidos com solo argiloso. O estudo foi realizado em modelos reduzidos para duas escalas de comprimento, correspondentes a 1:67 e 1:76, com o objetivo de estudar o mecanismo de penetração dos torpedos metálicos e nos fenômenos de hidrojateamento em solo argiloso. O solo foi caracterizado e nos ensaios foram identificados e avaliados: (a) a influência do fluxo de água a partir das variáveis vazão, pressão, velocidade e diâmetro do jato, (b) a influência da massa e diâmetro das hastes metálicas e (c) a interação solo-estaca pós instalação. Os resultados apresentados indicaram que as maiores profundidades de penetração das estacas torpedo foram atingidas para os modelos de maior massa, e também para as maiores vazões do fluxo de água, para maiores pressões de fluxo de água e menor resistência não drenada do solo. Com base nas variáveis controladas foi possível estabelecer um modelo e uma equação para estimar a profundidade máxima atingida por estacas metálicas instaladas por fluidização. Estes resultados complementaram estudos anteriores e permitiram uma avaliação, baseada em modelos reduzidos, na eficiência do jateamento, parâmetros de controle do mecanismo de erosão, profundidade máxima de penetração no leito marinho e capacidade de carga das estacas, sempre utilizando conceitos de similaridade para relacionar modelo e protótipo. / Deep water oil fields discovered by Petrobras in Brazil in 2006 brought new challenges to the offshore industry. Thus, for exploring these basins, research and technology investments are necessary to ensure production conditions, which require development of technological foundation systems, nearshore and offshore. Petrobras designed and patented an anchoring system, the torpedo pile, which serves as foundation to various types of production structures in ultra-deepwater. Torpedo is a steel pile, filled with ballast, having a cone-shaped tip. The anchor installation consists in the free fall of the torpedo from a designated height above the seafloor, which dynamically penetrates into marine clay by the action of gravity acceleration of the torpedo mass. This thesis presents an alternative installation technique for torpedo anchors based on tests carried out in reduced physical models following the law of similarity by the Froude number. The goal was to install model piles by applying downward vertical water jets. The water jetting tests were performed in the laboratory using parallelepiped-shaped tanks with acrylic walls, filled with clayey soil. The study was conducted on reduced scale models for two length scales, corresponding to 1:67 and 1:76, with the aim of studying the penetration mechanism of metal torpedoes and water jetting phenomena in clayey soil. The soil was characterized and tests were performed to identify and evaluated: (a) the influence of water flow, pressure, penetration rate and diameter of the jet, (b) the influence of the mass and diameter of the metal rods and (c) soil-pile interaction after installation. The results presented indicated that the greatest depth of penetration of torpedo piles was achieved for higher mass models, also for the higher flow rates, the Reynolds number, higher water flow pressures and lower undrained resistance of the soil. Based on these variables it was possible to establish a model and an equation to estimate the maximum depth of penetration of metal piles installed by fluidization. These results complement previous studies and allowed an assessment based on reduced models, the jetting efficiency, the control parameters of the erosion mechanism, the maximum penetration depth on the seabed and load capacity of the piles, always using concepts of similarity to relate model and prototype.

Additive manufacturing brings versatility and new degree of freedom for part design and manufacturing possibilities. Binder jetting is powder bed printing technique that does not require direct energy transfer rather binding powder metal particles through mechanical entanglement by use of the organic binder. The polymer chains in the solution hardens when heated thus creating a green part. Green parts are sintered in high temperature to adhere metal powder particles together creating a solid body. Binder jetting still developing to its full potential in scalability and material portfolio. This thesis aims to contribute know how in process and material development of H13 tool steel in very fine particle size distributions from -16 µm to -10µm. Process parameters as well as sintering cycle developed specifically for H13 fine powders. With 52 samples printed, sintered in four different temperatures and analyzed material properties such as density and hardness to evaluate how particle size distributions affect printing process, densification and shrinkage in the sintering. Density of the green body has been evaluated through measurements of dimensions and weight, sintered density was analyzed by Archimedes method and light optical metallography. Trials for the processing and evaluation of the powders concluded that it is possible to use ultra-fine PSDs in binder jetting process with good results, this opens up opportunity for increased sustainability and profitability for powder manufacturing industry. Particle size distribution of -10 µm has outperformed the -16 µm in areas of relative density of the green body, sintered density and hardness. Although superior performance, the -10 µm requires higher ultrasonic intensity and lower spreading speed to achieve homogeneous powder bed. For the -16 µm powder it is worth noting that it is possible to bring up green density with further process development. Although materials presented high hardness in as printed state compared to that of PIM manufactured parts, achieved hardness is not satisfactory for the applications of the alloy and requires heat treatment corresponding to customer requirements.