La technologie de projection plasma atmosphérique (APS) est largement utilisée pour des applications industrielles. Les revêtements élaborés par APS présentent généralement certains défauts. Les travaux effectués dans cette étude ont consisté à étudier et à développer un nouveau moyen pour assurer à la fois un refroidissement efficace au cours de procédé de projection APS et une adaptation des conditions superficielles en vue d’élaborer des revêtements de haute qualité. Ce moyen consiste à la projection de glace carbonique (glace sèche ou dioxyde de carbone solide) en association avec la projection plasma. Des simulations numériques ont été réalisées, qui ont permis de constater que les dimensions de la buse de projection de glace carbonique, la pression du gaz propulsif, et les propriétés des pellets de CO2 influencent sensiblement la vitesse des pellets de CO2. A partir de ces éléments, des dimensions optimales ont été évaluées. Afin d’examiner l’effet de la projection de glace carbonique sur les revêtements réalisés par projection thermique, plusieurs types de matériaux ont été considérés, trois métalliques (acier, CoNiCrAlY et aluminium pur) et trois céramiques (Al2O3, Cr2O3 et ZrO2-Y2O3). Les microstructures des revêtements metalliques réalisés avec projection de glace sèche présentent moins d'oxydes et moins de porosité par rapport à ceux déposés par APS classique. Dans certains cas l’adhérence peut aussi être améliorée. Pour les revêtements céramiques, une réduction de la porosité ainsi qu’une amélioration significative de l’adhérence des revêtements ont été constatés. Pour le dépôt de ZrO2-Y2O3, la résistance aux chocs thermiques a été améliorée en utilisant des paramètres spécifiques. La projection de CO2 peut légèrement déformer la surface des substrats de faible dureté, et nettoyer les pollutions superficielles sur le substrat et conduire à une contrainte de compression plus élevée et à un refroidissement efficace. Il est à noter toutefois qu’un problème de condensation de la vapeur d’eau peut intervenir en cas de refroidissement du substrat trop important. / The technology of atmospheric plasma spraying (APS) is widely used for industrial applications. The coatings produced by APS generally show defects. The work was conducted to investigate and develop a new method to ensure both an effective cooling during the APS process and the adaptation of the surface condition in order to develop high quality coatings. This solution is dry ice (CO2) blasting in combination with thermal spraying. Firstly, numerical simulations were carried out, which revealed that the nozzle size of dry ice blasting, the propellant pressure and the properties of CO2 pellets, significantly affect the velocity of CO2 pellets. From these elements, the optimal dimensions were evaluated. To examine the effects of dry ice blasting on the coatings produced by thermal spraying, several types of materials were considered, three metals (steel, CoNiCrAlY and pure aluminum) and three ceramics (Al2O3, Cr2O3 and ZrO2-Y2O3). The microstructure of metal coatings produced with dry ice blasting show fewer oxides and less porosity compared to those deposited by conventional APS. In some cases the adhesion can be improved. Regarding ceramic coatings, a reduction in porosity and a significant improvement in the coating adhesion were observed. For the deposition of ZrO2-Y2O3, an improvement in thermal shock resistance was achieved using specific parameters. Dry-ice blasting may slightly impact the surface of the substrates with low hardness and could clean the surface pollutions on the substrate and lead to a higher compressive stress and an effective cooling. However, it is noted that the problem of the condensation of water vapor can occur in case of intense cooling of the substrate.

Successful wind power projects start with a realistic representation of the surface, more specifically the surface roughness of the site. This thesis investigates the use of airborne laser scans to model the surface roughness around a new wind farm. Estimations are made to find out how forest management and tree growth affects roughness length and displacement height. Data from scans two years apart for a specific site is provided by the Swedish governmental land registration authority. Next, tree height and plant area index methods are applied and analyzed using MATLAB. The results shows a difference of roughness length between 10.34% and 36.21% during an eight year period. WindPRO/WAsP is used to import roughness lengths for four specific cases. Height contour lines and meteorological data is taken from a long term corrected MESO data set. The results indicate a reduction in uncertainty in annual energy production between 0.79% and 2.89% across four different cases. This effect becomes significantly larger (12.76%) when comparing with classical land cover maps. Further on, effects of turbulence intensity are simulated.Finally, the results of a survey, sent to three large forest land owners in Sweden, show there is an interest in adapting forest management plans in favor of wind energy production if benefits can be shared.

Ce mémoire présente une méthode visant à mettre en évidence l’influence de l’intégrité de surface obtenue en tournage, sur la fatigue de l’acier 15-5PH. Le travail réalisé consiste à développer des moyens d’obtention de surfaces à intégrités maitrisées, puis à réaliser des essais de fatigue pour observer l’influence des paramètres d’intégrité. Les procédés de tournage et de galetage sont utilisés pour obtenir des lots d’éprouvettes possédant différentes intégrités de surfaces. Ces éprouvettes sont ensuite toutes caractérisées, en rugosité et contraintes résiduelles, de manières non destructives. Certaines éprouvettes font l’objet d’analyses complémentaires pour caractériser l’état de la matière sous la surface. Ces analyses permettent de constituer des lots d’éprouvettes possédant des caractéristiques de surfaces très proches. Toutefois, il a été mis en évidence une très grande sensibilité de l’intégrité de surface générée, vis-à-vis du diamètre de la pièce usinée, ce qui se traduit par une dispersion importante des intégrités de surface obtenues. Les lots constitués sont ensuite testés en fatigue sur une machine de flexion rotative (R = -1) selon la méthode Staircase. Cette méthode permet de déterminer la limite d’endurance avec 50 % de probabilité de rupture pour un nombre de cycles donné. Les résultats sont ensuite confrontés aux intégrités de surface des lots pour déterminer les caractéristiques les plus influentes. Une comparaison des données expérimentales est réalisée avec les modèles de la littérature. Il est montré que ces modèles ne parviennent pas à décrire de manière satisfaisante le comportement en fatigue vis à vis de la rugosité ou du niveau de contraintes résiduelles. L’analyse de ces résultats montre que le profil de contraintes résiduelles, dans le cas du 15-5PH, est la caractéristique la plus influente sur la tenue en fatigue. La rugosité n’apparait pas comme un facteur d’influence notable, à l’exception des cas où les contraintes résiduelles ont un niveau très faible. Des pistes d’améliorations sont enfin suggérées pour améliorer la prise en compte de l’intégrité de surface dans le cadre d’un dimensionnement en fatigue. / This thesis aims to show a method to highlight the influence of surface integrity obtained by turning on the fatigue of a 15-5PH steel. Several ways are developped to obtain desired surface integrities, then fatigue test are performed to observe the influence of surface integrity parameters'. Turning and ball burnishing were used to achieve specimens with differents surface integrities. Theses samples are then fully characterized in term of surface roughness and residual stresses, in a non-destructive way. Some specimens are subject to further analysis to characterize the state of the material under the surfaece. These analyses are used to create batches of specimens with very close surfaces characteristics. However, it has been shown a high sensitivity of the generated surface integrity, with respect to the workpiece diameter, which result in a significant dispersion of surface integrities obtained. Batches are then tested on a rotating bending test machine (Stress ration R=-1) thanks to the Staircase method, in order to determine the fatigue limit at two billion cycle with a 50% failure probability. The results are then compared with the surface integrities in order to determine the most influencial parameter. A comparison of the experimental datas with models in the literature is performed. It is shown that models are unable to describe the fatigue behavior with respect to the roughness or the residual stress state. The results analysis shows that residual stresses profile, in the case of 15-5PH steel, is the most influencial parameter on the fatigue life. Roughness does not appears as a factor of major influence, except in cases where residual stresses have a very low level. Prospects for improvement are finaly suggested in order to improve the consideration of surface integrity during the fatigue design of parts.

This thesis examines the role of remote sensing technology in providing information to northern residents of Kugluktuk and Cambridge Bay, Kitikmeot region of Nunavut, Western Canadian Arctic, for the purpose of improving sea ice trafficability and safety. The main objectives of this thesis include 1) the identification of northern community sea ice information needs that can be addressed using remote sensing, and 2) the creation of remote sensing-based products showing sea ice surface roughness information useful to community sea ice trafficability and safety. Thesis outcomes include the refinement and dissemination of information and products with these communities. Research methods involved interviews with northern community members that were analysed using thematic analysis, as well as quantitative assessments of sea ice roughness using satellite datasets. Maps of sea ice surface roughness were created using Sentinel-1 synthetic aperture radar and the Multi-angle Imaging Spectroradiometer, and were evaluated against fine-scale airborne LiDAR data. / Graduate / 2020-07-31

In dieser Studie wurde das Verhalten eines neuentwickelten Hartmetallfinierers der Firma Brasseler und herkömmlicher grober und feiner Diamantfinierer der Firmen Intensiv und Brasseler an vier verschiedenen Füllungsmaterialien untersucht. Bei dem Hartmetallfinierer handelt es sich um ein Kombinationsinstrument, das sich im Rechtslauf durch eine hohe Arbeitsleistung auszeichnet und zum Konturieren von Füllungen gedacht ist. Im Linkslauf soll das Instrument zur Feinausarbeitung eingesetzt werden, die Arbeitsleistung ist geringer. In 120 extrahierte menschliche Zähne wurden ovale Klasse-V-Kavitäten (Länge: 4 mm, Breite: 3 mm, Tiefe: 2 mm) präpariert, die jeweils zur Hälfte im Schmelz und Dentin lagen. Jeweils 30 Zähne wurden nach Herstellerangaben mit demselben Füllungsmaterial gefüllt (Prodigy, Silux Plus, Dyract AP, Fuji LC). Anschließend wurden die Restaurationen zunächst mit den gröberen Finierdiamanten und dem Kombifinierer im Rechtslauf konturiert. Jeweils 10 Proben eines jeden Füllungsmaterials wurden mit einem der Instrumente bearbeitet. Auf diese Weise ergaben sich 12 Material-Instrumenten-Kombinationen. Nach dreiwöchiger Wasserlagerung wurde die Rauhigkeit der Füllungsoberflächen mit einem Profilometer gemessen. Außerdem erfolgte eine Auswertung der Randqualität mittels quantitativer Randanalyse. Im Anschluß hieran wurden die Füllungen mit den feineren Diamantinstrumenten bzw. dem Kombifinierer im Linkslauf finiert. Die Füllungen wurden anschließend einer Temperaturwechselbelastung unterzogen (2000 Zyklen zwischen 5°C und 55°C). Erneut erfolgte eine quantitative Randanalyse und eine Oberflächenrauhigkeitsmessung. Die statistische Auswertung der Daten ergab, daß der Kombifinierer im Linkslauf im Gegensatz zu den feinen Diamantfinierern keine Verbesserung der Oberflächenqualität bewirkt. Die Auswirkungen der Instrumente auf die Randqualität ist gleich. Fuji LC weist die höchste Oberflächenrauhigkeit auf. Die übrigen Füllungsmaterialien unterscheiden sich diesbezüglich nicht statistisch signifikant voneinander. Die Silux Plus Restaurationen zeichnen sich durch einen im Vergleich zu den übrigen Materialien hohen Anteil an Randspalten sowohl im Dentin- als auch im Schmelzbereich aus. Die Prodigy Füllungen haben signifikant mehr Randspalten im Dentin als Fuji LC und Dyract AP Füllungen, jedoch auch signifikant weniger als Silux Plus im gleichen Bereich. / In this study a newly developed tungsten carbide finishing bur (Brasseler) and conventional coarse and fine grit finishing diamonds of the companies Intensiv and Brasseler were studied with four different filling-materials. The carbide bur is a combination-instrument, that distinguishes itself in the right-hand rotation by a high performance and is intended for the contouring of fillings. When used in a left-hand rotation the instrument should be applied for polishing. In this case the cutting performance is inferior. Oval class-V-cavities (length: 4 mm, width: 3 mm, depth: 2 mm) were prepared into 120 extracted human teeth with one half of the margin length in dentin and one half in enamel. In each case, 30 teeth were filled according to manufacturer-recommendation with the same filling-material (Prodigy, Silux Plus, Dyract AP, Fuji LC). Subsequently the restorations were trimmed with the coarser finishing diamonds and the combination bur with a right-hand rotation. Ten samples of each filling-material were ground with one of the instruments. Thus 12 material-instrument-combinations were established. After three weeks of water-storage, the surface roughness of the fillings was measured with a profilometer. Furthermore, an evaluation of the margin-quality was carried out by means of quantitative margin analysis. After this, the fillings were either polished with the finer diamond-instruments or with the combination-instrument in a left-hand rotation. Afterwards the samples were subjected to a thermocycling procedure (2000 cycles between 5°C and 55°C). Again a quantitative margin analysis and a surface-roughness-measurement were performed. In contrast to the fine diamond instruments, the statistical evaluation of the data revealed that the combination finishing bur does not improve the surface quality in a left-hand rotation. The effect of the instruments on the margin quality is the same. Fuji LC shows the highest surface-roughness, the other filling-materials do not differ statistically significantly from one another. The Silux Plus restorations are characterized by a high percentage of marginal openings in both enamel and dentin. The Prodigy fillings show significantly more marginal gaps in dentin than Fuji LC and Dyract AP fillings, but significantly less than Silux Plus in the same area.

Thin polymer films and their properties have been investigated. The characteristics of crystalline polymers according to film thickness have been improved using polycaprolactone (PCL). The melting enthalpy of PCL has increased when the film thickness decreased and the peak melting temperature showed no significant changes with film thickness. Film thickness variation influenced surface roughness and crystal size. Optical microscope images showed the rougher surface of thicker films. The spinning time has shown no influence on film thickness and no significant changes to surface roughness. Thin films of block copolymers were used in the surface modification study; films studied included poly(styrene-b-butadiene-b-styrene) (SBS) and poly(styrene-b-isoprene-b-styrene) (SIS) and their surface modifications have been controlled using different methods of treatment. Films of SIS heated at different temperatures have shown different surface texture and roughness. Films treated at low temperature (45 °C) had smooth surfaces when compared with films heated at high temperature (120 °C and 160 °C). Phase separation of SIS heated at (120 °C and 160 °C) caused bulges of different sizes to cover the surface. The height and width of the bulges showed variation with film thickness and heating. Substrate interaction with SBS and SIS block copolymer films showed different surface texture when using the same type of substrate and different texture were obtained when SBS solutions were spun onto different substrates. It has been demonstrated that using different solvents in copolymer preparation caused different texture. Thermal and surface property variations with film thickness have been improved using amorphous polymers. Surface roughness of poly(methyl methacrylate) PMMA and disperse red 1-poly(methyl methacrylate) DR1-PMMA, PMMA has improved using thickness variation. Glass transition temperature measurement has increased when film thickness was increased. The glass transition temperature (Tg) and surface roughness of UV15 UV - curable coating polymer has been modified using UV curing and heating methods. Tg variation was observed when curing time and curing intensity were changed causing the optical properties of the polymer to be more variable. A plasma etcher caused wrinkles to occur on the surface of unheated UV15. Tg of UV15 increased when curing time increased. The Fourier Transform Infrared Spectroscopy (FTIR) spectra of cured UV15 film have shown peak variations of the ester and carbon double bond regions over the range of 1850-1700 cm-1. Urethane-Urea (UU) Polymer thin films were used to investigate optical properties and develop an optical waveguide. Absorption and transmission properties of light using non-linear optical (NLO) polymer was investigated and used in optical waveguide fabrication. Refractive indices were measured to examine UU films at two different wavelengths. A UU film of 1 µm thickness caused a maximum absorption at max = 471 nm also obtained at 810 nm wavelength. Many methods of fabrication were used; photolithography, plasma etching in a barrel reactor and thin film deposition using sputtering and evaporation. Etched depths from 1 μm to 100 μm were obtained. An optical waveguide has been prepared using plasma etching of a cured UV15 as a cladding layer on a silicon substrate.

The use of hydrophobic surfaces is important for many processes both in nature and industry. Interactions between hydrophobic species play a key role in industrial applications such as water-cleaning procedures and pitch control during papermaking but they also give information on how to design surfaces like hydrophobic mineral pigments. In this thesis, the influence of surface properties on wetting and interaction forces has been studied. Surfaces with close-packed particles, pore arrays, randomly deposited nanoparticles as well as reference surfaces were prepared. The atomic force microscope (AFM) was utilized for force and friction measurements while contact angles and confocal Raman microscopy experiments were mainly used for wetting studies. The deposition of silica particles in the size range of nano- to micrometers using the Langmuir-Blodgett (LB) technique resulted in particle coated surfaces exhibiting hexagonal close-packing and close to Wenzel state wetting after hydrophobization. Force measurements displayed long-range interaction forces assigned to be a consequence of air cavitation. Smaller roughness features provided larger forces and interaction distances interpreted as being due to fewer restrictions of capillary growth. Friction measurements proved both the surface structure and chemistry to be important for the observed forces. On hydrophobic pore array surfaces, the three-phase contact line of water droplets avoided the pores which created a jagged interface. The influence of the pores was evident in the force curves, both in terms of the shape, in which the three-phase contact line movements around the pores could be detected, as well as the depth of the pores providing different access and amount of air. When water/ethanol mixtures were used, the interactions were concluded to be due to ethanol condensation. Confocal Raman microscopy experiments with water and water/ethanol mixtures on superhydrophobic surfaces gave evidence for water depletion and ethanol/air accumulation close to the surface. Force measurements using superhydrophobic surfaces showed extremely long-range interaction distances. This work has provided evidence for air cavitation between hydrophobic surfaces in aqueous solution. It was also shown that the range and magnitude of interaction forces could, to some extent, be predicted by looking at certain surface features like structure,roughness and the overall length scales. / <p>QC 20121011</p>

No description available.

To facilitate the transition of Stereolithography (SLA) into the manufacturing domain and to increase its appeal to the micro manufacturing industry, process repeatability and surface finish need to be improved. Researchers have mostly focused on improving SLA surface finish within the capabilities of commercially available SLA machines. The capabilities of these machines are limited and a machine-specific approach for improving surface finish is based purely on empirical data. In order to improve surface finish of the SLA process, a more systematic approach that will incorporate process parameters is needed. To achieve this, the contribution of different laser and process parameters, such as laser beam angle, irradiance distribution, and scan speed, to SLA resolution and indirectly to surface finish, need to be quantified and incorporated into an analytical model. In response, a dynamic analytical SLA cure model has been developed. This model has been applied to SLA geometries of interest. Using flat surfaces, the efficacy of the model has been computationally and experimentally demonstrated. The model has been applied to process planning as a computational inverse design method by using parameter estimation techniques, where surface finish improvement on slanted surfaces has been achieved. The efficacy of this model and its improvement over the traditional cure models has been demonstrated computationally and experimentally. Based on the experimental results, use of the analytical model in process planning achieves an order of magnitude improvement in surface roughness average of SLA parts. The intellectual contributions of this research are the development of an analytical SLA cure model and the application of this model to process planning along with inverse design techniques for parameter estimation and subsequent surface finish improvement.

Many problems exist in current photoresist designs that will limit their ability to obtain the performance required for future generations of integrated circuit devices. In order to overcome these challenges, novel resist designs are required, along with advancement in the fundamental understanding of the source of these problems. A mesoscale kinetic Monte Carlo simulation of resists was developed to probe the effects of changes in resist formulation and processing. A detailed SEM simulator was developed in order to better understand the effect of metrology on the characterization of the final resist relief image. Several important structure-property relations were developed for the prediction of glass transition temperature in molecular resists and the prediction of the solubility of molecular resists in developer. Five new families of molecular resists were developed that provide solutions to some of the limitations in current resist designs. Single component molecular resists have all of the functional groups required to act as a chemically amplified resist contained in a single molecule. This eliminates inhomogeneities in the resist and provides improved line edge roughness. Non-chemically amplified molecular resists were developed that have very good sensitivity due to the unique dissolution properties of molecular resists. Negative tone molecular resists were developed that have an excellent combination of resolution, sensitivity, and line edge roughness with better resolution than has been previously seen in negative tone resists. Control methods were also developed to improve the resolution of these types of negative tone resists even further.