Densification and submergence of floating crude oil is proposed as a novel oil spills treatment method. Surface application of dry granular materials (e.g., quartz sand, limestone) on top of a floating oil layer increases the density of the floating oil phase/granule mixture and leads to formation of relatively large and stable aggregates with significant amounts of captured oil. The aggregates separate from the floating hydrophobic phase and settle by gravity. Implementation of this method will reduce the impact radius of a spill and its mobility, preventing direct contamination of beaches, coastal flora and fauna. The major objective of this research was to examine interactions of particles with hydrophobic liquid-water interface from different perspectives. The important characteristics of the process, such as oil removal efficiencies, optimal particle-to-oil ratios and particle size ranges, were experimentally defined. A series of experiments was conducted to investigate aggregation and dissolution rate constants of the submerged hydrophobic liquids in salt water and deionized water, and to study the impact of the surface porosity of the granular particles on oil capture efficiencies. In addition to crude oil (South Louisiana crude, MC 252), aggregation volumes of quartz sand with other hydrophobic liquids (alkanes and aromatics) were analyzed in relation to wetting characteristics and physical properties of the liquids. A classification of the main types of oil-particle aggregates was developed based on the formation characteristics of the aggregates. Moreover, under specific conditions, depending on the application rates of the granular materials, unique interactions of the particles with the hydrophobic liquid-water interface were observed and defined (bowl formation and roping). These concepts can be utilized to control surface mobility of floating oils, especially during the initial stages of an oil spill, while the oil layer is intact, and when other treatment methods may not be suitable near coastal areas, where transport of floating oils can significantly impact coastal ecosystems.

This thesis investigates wave loading on bodies in the free surface using smoothed particle hydrodynamics (SPH). This includes wave loading on fixed bodies, waves generated by heaving bodies in still water and the heave response of a body in waves, representing a wave energy device. SPH is a flexible Lagrangian technique for CFD simulations, which in principle applies to steep and breaking waves without special treatment allowing us to simulate highly nonlinear and potentially violent flows encountered in a real sea. However few detailed tests have been undertaken even with small amplitude waves.This research uses the open-source SPH code SPHysics. First two forms of SPH formulation, standard SPH with artificial viscosity and SPH-Arbitrary Lagrange Euler (ALE) with a Riemann solver, are used to simulate progressive waves in a 2-D tank. The SPH-ALE formulation with a symplectic time integration scheme and cubic spline kernel is found to model progressive waves with negligible dissipation whereas with the standard SPH formulation waves decay markedly along the tank. We then consider two well-defined test cases in two dimensions: progressive waves interacting with a fixed cylinder and waves generated by a heaving semi-immersed cylinder. To reduce computer time in a simple manner a variable particle mass distribution is tested with fine resolution near the body and coarse resolution further away, while maintaining a uniform kernel size. A mass ratio of 1:4 proved effective but increasing to 1:16 caused particle clumping and instability. For wave loading on a half-submerged cylinder the agreement with the experimental data of Dixon et al. (1979) for the root mean square force is within 2%. For more submerged cases, the results show some discrepancy, but this was also found with other modelling approaches. For the heaving cylinder, SPH results for the far field wave amplitude and vertical force on the cylinder show good agreement with the data of Yu and Ursell (1961). The variable mass distribution leads to a computer run time speedup of nearly 200% in these cases on a single CPU. The results of the vertical force and wave amplitude are shown to be quite sensitive to the value of the slope limiter in the Riemann solver for the 2-D heaving cylinder problem. A heaving 2-D wedge or 3-D cone whose oscillatory vertical motion is prescribed as the elevation of a focused wave group is a precise test case for numerical free-surface schemes. We consider two forms of repulsive boundary condition (Monaghan & Kos, 1999, and Rogers et al., 2008) and particle boundary force (Kajtar and Monaghan, 2009) for the 2-D wedge case, comparing the result with the experimental data of Drake et al. (2009). The repulsive boundary condition was more effective than the particle boundary force method. Variable particle mass with different kernel sizes was then tested for 2-D problems for mass ratios of 1:4, 1:16 and 1:4:16 with satisfactory results without particle clumping and instability. For the 3-D cone case, SPH reproduces the experimental results very closely for the lower frequency tested where there is no separation from the bottom surface of the body but for the higher frequencies the magnitudes of force minima were underestimated. The mass ratios of 1:8 and 1:8:27 in two and three nested regions are tested for the 3-D cone problem where a computer run time speedup of nearly 500% is achieved on 16 processors for the mass ratio of 1:8.Finally, the floating body of a heaving wave energy device known as the Manchester Bobber is modelled in extreme waves without power take-off. The results for a single float are in approximate agreement with the experiment.

Placing wave energy devices within close proximity to each other can be beneficial as the costs of deployment, maintenance and infrastructure are reduced significantly compared to if the devices are deployed in isolation. A mathematical model is presented in this thesis which combines linear wave theory with a series of linear driven harmonic oscillators to model an array (group) of floating wave energy devices which move predominantly in heave (vertically) in a train of incident regular waves. Whilst similar mathematical models have been used previously to investigate interactions between fluids and groups of structures, much of the published work does not address array configurations or device constraints that are relevant to designers of structure-supported array devices. The suitability of linear theory for application to closely spaced arrays is assessed in this thesis through comparison to small-scale experimental data and by evaluation of the magnitude of second-order hydrodynamic forces. Values of mechanical damping and mass are determined for each element of an array in order to achieve the maximum power from an array of floats without requiring the knowledge of the motion of every float within the array in order to apply the forces to any one float. Further to this, the analysis of floats of varying geometry is performed in order to assess the possibility of array optimisation through the variation of float geometries within a closely spaced array.It is shown in this thesis that linear theory provides a reasonable prediction of the response of floats that are sufficiently close together to interact for most wave frequencies to which the arrays are likely to be subjected. Under the assumption of easily implementable mechanical damping, it is determined that the power output from an array of floats of equal geometry can be increased by specifying different magnitudes of mechanical damping on each float independently of the radiation damping. Variations in submerged float geometries for the purpose of manipulating array characteristics according to the incident wave frequency are best applied through the variation in draft of a single geometry. Variations in submerged float geometry which occur close to the free surface are found to be of the greatest significance. Where the float is uniform in cross-section, the most appropriate method to select float drafts within an array is found to be based on the evaluation of the total damping on each float.

Nesta dissertação é apresentado o estudo dos transistores de porta flutuante (Floating Gate Transistor - FG Transistor), sua modelagem, e a análise do efeito da dose de ionização total (Total Ionizing Dose- TID) sobre os transistores FG. Para isto foi procurado e implementado um modelo de simulação elétrica do transistor FG em condições de leitura (análise DC), baseado no cálculo quantitativo da tensão na porta flutuante em função das tensões nos terminais do transistor, no valor de carga armazenado na porta flutuante e nos coeficientes de acoplamento capacitivo que apresentam este tipo de dispositivos. Para a análise do efeito TID, a tensão limiar do transistor MOS foi variada usando o método de simulação Monte Carlo, tendo em conta as variações da tensão limiar que apresentam os transistores FG submetidos na radiação ionizante. O estudo obteve como resultado a confirmação da perda de carga do FG à medida que é incrementada a dose de radiação, o que implica uma alteração na característica de retenção de carga que caracteriza as células de memórias não voláteis (Non Volatile Memory - NVM). / In this dissertation work, a study of the the floating gate Transistor (FG transistor) performed. The focus in the electrical modeling, and the analysis of the impact of the Total Ionizing Dose (TID) on the electrical performance of the device. Aiming electrical level simulation, different electric simulation models for the FG transistor in read conditions (DC analysis) were evaluated and the model best suited for implementation into the simulation tool was selected. The selected model is based on Floating Gate voltage calculation as a function of polarization voltage of the FG transistor terminals, the stored charge value in the Floating Gate and the capacitive coupling coefficient presented by this device. For the TID analysis the threshold voltage of the MOS transistor was shifted by means of a Monte Carlo simulation method, considering the threshold voltage variations when the FG transistor is subjected to the ionizing radiation.The analysis lead to the confirmation that the loss charge stored in the FG increases with the radiation dose, affecting the retention characteristics of the memory cells.

By adapting Mitchell's algorithm for floating-point numbers, one can efficiently perform arithmetic floating-point operations in an approximate logarithmic domain in order to perform approximate computations of functions such as multiplication, division, square root and others. This work examines how this algorithm can be improved in terms of accuracy and hardware complexity by applying a set of various methods that are parametrized and offer a large design space. Optimal coefficients for a large portion of this space is determined and used to synthesize circuits for both ASIC and FPGA circuits using the bfloat16 format\@. Optimal configurations are then extracted to create an optimal curve where one can select an acceptable error range and obtain a circuit with a minimal hardware cost.

This thesis developed high-torque-capacity floating opposing arm clutches that are manufactured with standard economical manufacturing processes, while maintaining critical performance characteristics. Contact engagement speed and torque capacity models were created for the Hoffco-Comet, floating-opposing-arm (FOA), and floating 1 (F1) clutches. Sensitivity analyses were performed to identify key design parameters. A robust compliant FOA clutch was designed by minimizing the tolerance for both contact engagement speed and torque capacity. The robust design insures that the clutch will operate within the prescribed application constraints. Additional modeling showed that using a layered clutch would significantly tighten the contact engagement speed and torque performance tolerances. The riveted layered clutch reduced engagement and torque tolerances by 83% in comparison to a single layer clutch. Two versions of the multi-layer FOA clutch were fabricated. Each clutch consisted of 10 layers and assembled into the drum of the benchmark clutch. Testing showed that the MFOA clutch's torque-speed characteristics performed comparable to the benchmark clutch. In addition, testing validated the torque-speed models and showed the validity of using multiple layers for future manufacturing.

This thesis deals with the design of a floating point module, which allows to perform operations with floating point operands that have any bit width. For this purpose, the module is implemented as a template class in C ++. The module is designed to allow it to be used when designing an application-specific processor. First, the floating point number and template functions in c ++ are described. In the practical part the algorithms of the individual operations and the design of the module itself are described as template libraries.

The Master’s Thesis aims to laboratory test the possibilities of utilization mica separate, which arises during the process of floating kaolin as a by-product together with sand. Mica and sand are then separated by flotation or vibration. The mica separate thus formed was subjected to analysis. XRD and heating microscopy methods were used for analysis. Subsequently, experiments with mica separation as a filler in composites based on epoxy resins were set up and performed. Furthermore, the separate was tested as a part of plasters and visual building elements. Last but not least, the separate was mixed into the ceramic, which was then subjected to firing in the selected mode. The diploma thesis provides a comprehensive overview of the above-mentioned possibilities of using mica separation, which is based on a sufficient amount of experimental data.

Les biofilms bactériens, communautés multicellulaires adhérentes à une surface et enrobées d’une matrice extracellulaire, sont cruciaux pour le maintien de la plupart des écosystèmes de notre planète mais représentent également une menace pour la santé humaine. Leur éradication est un véritable défi pour la microbiologie moderne du fait de leur résistance élevée aux antibiotiques. Providencia stuartii est une bactérie Gram-négative connue pour sa forte capacité à former des biofilms dans le tractus urinaire humain, qui est responsable pour environ 10% des infections nosocomiales urinaires chroniques. Nous avons montré que cette souche bactérienne exploite un moyen de socialisation supplémentaire préalable à l’adhésion des cellules aux surfaces et la sécrétion d’une matrice extracellulaire, les communautés flottantes. Les deux porines de P. stuartii, Omp-Pst1 et Omp-Pst2, soutiennent la formation des communautés flottantes en s’auto-associant à travers leurs boucles extracellulaires pour former des dimères de trimères (DOTs) intercellulaires. La formation des DOTs, rivetant les cellules adjacentes entre elles, est médiée par des forces électrostatiques et des interactions de type steric zipper.Les deux grands objectifs de la thèse ont été i) de caractériser les impacts environnementaux sur l’établissement et la survie des deux types de communautés formés par P. stuartii, et ii) d’empêcher la socialisation bactérienne par inhibition des DOTs de porines. Nos résultats ont montrés que des peptides mimant les résidus impliqués dans les interactions de type stérique zipper des DOTs de porines, et couplés à de la coumarine, sont prometteurs pour diagnostiquer les infections à P. stuartii. De plus, nous avons mis en avant qu’une combinaison d’antibiotiques avec certains de ces peptides est une nouvelle approche thérapeutique envisageable pour lutter contre les infections de P. stuartii. Nos résultats montrent aussi que les futurs traitements devraient être évalués sur les communautés flottantes et les biofilms adhérents, dans des conditions imitant les voies urinaires, afin d’être efficaces et potentiellement éradiquer P. stuartii. / Bacterial biofilms are multicellular communities adherent to surfaces and surrounded by an extracellular matrix. They are crucial for maintaining most of our planet’s ecosystems, but also a threat to human health. Biofilm eradication is one of the greatest challenges of modern microbiology due to their high resistance to antibiotics. In this PhD, we focused on Providencia stuartii, a Gram-negative pathogen that forms biofilms in the human urinary tract and is responsible for about 10% of hospital-acquired urinary tract infections. P. stuartii exploits an additional means of socialization, forming floating communities of cells (FCCs), that later sediment and adhere onto surfaces yielding surface-attached biofilms (SABs). The two porins of P. stuartii, Omp-Pst1 and Omp-Pst2, are involved in FCC formation by self-association into intercellular dimers of trimers (DOTs). The main driving force behind DOT formation is electrostatic attraction, yet the DOT structure is locked-in by steric zipper interactions between facing extracellular loops.The two main objectives of this PhD were (i) to characterize the environmental impacts on the establishment and survival of the two type of socialized communities formed by P. stuartii, and (ii) to inhibit bacterial socialization by targeting porin DOTs. Our results reveal that peptides featuring residues involved in the steric zipper interaction of DOTs, and coupled with coumarin, are promising lead compound to diagnose P. stuartii infections. In addition, we tested combinations of antibiotics with some of these peptides and results suggest that is was a new therapeutic approach that can be envisaged to fight against P. stuartii infections. Future treatments should be evaluated on FCCs and SABs in conditions mimicking urinary tract, to be efficient and potentially eradicate P. stuartii.

Die Hupkraftverteilung eines airbagintegrierten Automobillenkrades wird mit Hilfe einer Parameterstudie in MathCAD so optimiert, das an jeder Krafteinleitungsposition die Hupe mit einer geforderten Mindestkraft betätigt werden kann. Nach der Modellierung in MathCAD der zugehörigen Geometrie und der Dimensionierung der Federlagerung ist das zugehörige mechanische Ersatzmodell mit Hilfe einer Parameterstudie verändert worden, so dass die Hupkraftforderung erfüllt wird.