Thesis (M.S.)--University of Wisconsin--Madison, 1966. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1983. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 240-244).

Carbon fibre-reinforced plastics (CFRP) are widely used in aerospace, automobile and other structural applications due to their superior mechanical and physical properties. CFRP outperform conventional metals in high strength-to-weight ratio. Usually, CFRP parts are manufactured near to net-shape;however,machining is unavoidable when it comes to assembly. Drilling the holes are essential to facilitate riveting and bolting of the components. However, conventional drilling (CD) induces different types of damages such as cracking, fibre pull-out, sprintling and delamination due to the abrasive nature, inhomogeneity and anisotropy of CFRP. A novel technique, ultrasonically-assisted drilling (UAD) is hybrid machining technique in which highfrequency (typically above 20 kHz) vibration are superimposed on a standard twist drill bit in axial direction using ultrasonic transducer. UAD has shown several advantages such as thrust force reduction, improving surface quality and lower bur-formation in drilling of conventional metals. UAD has also effectively been used for drilling brittle materials.

The thesis investigates the behaviour of aqueous montmorillonite suspensions and also the interactions between montmorillonite as a free standing film and in highly dispersed aqueous suspension with water soluble polymers used as additives in water based drilling fluids. FTIR microscopy and FTIR ATR spectroscopy have been employed to study in-situ dehydration of fully dispersed aqueous montmorillonite suspensions. The IR spectrum of the dispersed bentonite shows significant differences from that of a dry bentonite powder, which have been attributed to the hydration of the exchangeable cation. Drying, or concentrated salt solution causes the differences to disappear and this is attributed to the exchangeable cation settling back to its ditrigonal cavity in the silicate sheet of the mineral under these conditions. The adsorption of various molecular weights of neutral polyacrylamide (PAM) onto montmorillonite has been studied using FTIR transmission, ATR spectroscopy and XRD. Shifts seen in the NH[2] stretching and bending bands have been interpreted as being due to H-bonding with the outer co-ordination sphere of exchangeable cations. KCl has shown to have some influence on this system. Another neutral polymer used extensively in water based drilling fluids is polyalkylglycol (PAG). The adsorption of two molecular weights of this polymer from aqueous solutions of various concentrations have been monitored both in the presence and absence of KCl. The physical form of the montmorillonite (either as a free standing film or as a dispersed suspension), the concentration of the polymer solution, the polymer molecular weight and the presence of KCl all have significant effects on the adsorption of polymer. The stabilisation of montmorillonite films by PAG and PAG/KCl solutions has been monitored by ATR spectroscopy, and the dehydration of these films by polymer has been monitored using FTIR spectroscopy and XRD. The interaction of PAG is thought to be via hydrogen bonding with the innermost co-ordination sphere of the exchangeable cations which thus presents a hydrophobic surface to solvent molecules, preventing the film from collapse. Since all water based drilling fluids are multi-component systems, techniques previously used have been employed to study the competitive adsorption of the polyalkylglycol and polyacrylamide components. Preferential adsorption of the PAG is seen in these systems either due to the mass transport effects (PAG is considerably smaller than PAM) or due to PAG removing all but the inner cation hydration sphere, and presenting a hydrophobic surface for the PAM, and therefore preventing its adsorption.

This project studied the production of barium sulphate nanoparticles through inhibition of crystal growth, during precipitation, by different surfactants. Barium sulphate is the pure form of the ore baryte, which due to its high density and softness, is the most commonly used additive used to increase the density of drilling fluids. A non-agglomerating, stable nano-scale dispersion of barium sulphate particles would have significant technical and commercial impact in the drilling fluids industry. This thesis tested the possibility of precipitating barium sulphate and restricting its crystal growth with inhibitors, creating nanoparticles. Six inhibitors were tested; dodecanoic acid, palmitic acid, stearic acid, adamantane carboxylic acid, methylnonanoic acid and a mixture of phosphate esters known commercially as Fazewet. Precipitated, inhibited barium sulphate was characterised using powder XRD, DRIFT FTIR and solid-state NMR (SSNMR). All inhibitors were shown to form single-phase, orthorhombic barium sulphate crystals proving that the inhibitors affect only the surfaces of precipitated crystals and do not enter the crystal lattice. FTIR allowed the relative adsorbed concentration of each inhibitor to be assessed. The results indicate that adsorbed inhibitor increases with increasing inhibitor concentrations but that their attachment is not proportional to the concentration. In most cases concentrations of 0.1mol l-1 of inhibitor were sufficient to saturate the crystal surface. SSNMR also agreed with this although the sample size was too small, due to equipment restrictions, to make definitive conclusions. Through the use of the Debye-Scherrer equation, the crystallite size was calculated and showed that at concentrations of 0.2mol l-1 all inhibitors other than palmitic acid produced nano-scale (< 100nm) crystallites. Further analysis showed that further reductions could be achieved through precipitation in an alkaline pH environment, with the application of mechanical shear and by using adding 50% v/v of ethanol. iv Laser diffraction particle size analysis showed that the dominant factor in reducing particle size distribution was inhibitor concentration. The volume-based PSD used by the laser diffraction system was considered to distort excessively the particle sizes present and so analysis switched to dynamic light scattering. DLS showed that dodecanoic acid, palmitic acid and stearic acid, despite forming nano-scale crystallites, could not produce a nano-scale dispersion of barium sulphate and as such were unsuitable for use in drilling fluids. Stable nano-scale dispersions were found to have been formed when inhibited with adamantane carboxylic acid, methylnonanoic acid and Fazewet. DLS also confirmed that dispersed particle size rather than simply crystallite size could be reduced with an alkaline pH and high mechanical shear. Concentration was still the dominant effect, however with the smallest particles sizes (ZAvg) being observed at concentrations of 0.6mol l-1. The particle sizes for the three modifiers were approaching that of the crystallite size, suggesting that some further reduction is possible, but large reductions are unlikely. All three inhibitors produced sub 100nm ZAvgs, with the smallest produced by methylnonanoic acid of 43nm. Spherical nanoparticles were observed through the use of ESEM and TEM. Due to equipment time restrictions only 0.2mol l-1 treatment levels could be examined, but ESEM showed apparent nanoparticle clusters, later confirmed using pixel count and SFDA methods. TEM analysis showed discrete particles as small as 3nm, indicating that the lower limit for achievable particle size may be lower than PSD measurements would suggest. The results indicate that adamantane carboxylic acid, methylnonanoic acid and Fazewet sufficiently inhibit crystal growth to be potential candidates for the production of barium sulphate nanoparticles. These three inhibitors produce a barium sulphate dispersion that is stable and nano-scale even after drying and redispersion.

This thesis deals with designing and realization of a CNC drill. The body of the thesis is divided into three parts: Firstly, a design of a mechanical construction, secondly, an electronic scheme with its realization using industrial components and lastly, a design of a data export from an application for DPS EAGLE designing to G-KOD formate. The whole process should make drilling of plates with DPS or eventually the whole plate manufacturing more efficient and the quality and accurancy of a whole work should increase.

Les dépôts élaborés par projection thermique sont largement utilisés pour des applications de hautes performantes grâce à leurs propriétés mécaniques élevées (dureté et module d’Young). La détermination de ces propriétés est donc importante. Elles sont habituellement mesurées par des méthodes d’indentation en utilisant des indenteurs Vickers, Knoop et Berkovich. Mais ces méthodes de mesure nécessitent des équipements sophistiqués, une préparation rigoureuse des surfaces et la réalisation qui les rend coûteuse et difficile à mettre en oeuvre. Les travaux de cette thèse portent sur l’étude de la résistance à la perforation comme méthode alternative pour déterminer les propriétés mécaniques de dépôts céramiques élaborés par projection plasma. Pour ce faire, six poudres de compositions chimiques les plus souvent utilisées au niveau de l’industrie ont été sélectionnées pour élaborer les dépôts par projection plasma : Al2O3, TiO2, Al2O3-15wt % TiO2, Al2O3-43wt % TiO2, YSZ et Al2O3-YSZ. Les propriétés physico-chimiques et mécaniques des dépôts ont été déterminées. Les macro et micro duretés ont été déterminées par des indentations Vickers, le module d’Young a été calculé à partir des mesures de la micro dureté Knoop et la ténacité à la fracture a été déterminée à partir des résultats de micro dureté Vickers. La résistance à la perforation en mode statique a été conduite en utilisant des forets pour le perçage de verre et en traçant des courbes de charges (P) en fonction de la profondeur (h) d’enfoncement de la pointe du foret dans la surface du dépôt. Des rapports entre la charge et les aires de contact et de la section transversale de la pointe du foret (P/Ac et P/At respectivement), correspondant à la profondeur de pénétration du foret, ont été établis, permettant de définir la dureté par perforation statique (HDs). A partir des pentes ΔP/ΔAc et ΔP/ΔAt lors de la décharge des courbes P-h, le module d’élasticité par perforation statique (Es) a été déterminé. HDs et Es ont montré une bonne correspondance avec la micro dureté et le module d’Young déterminés par les méthodes classiques d’indentation et une haute reproductibilité des résultats. L’apparition de fissures et d’écaillage sur la surface des dépôts lors de l’étape de charge a mis en évidence une réduction de la pente des courbes P-h qui pourrait être utilisée pour trouver des corrélations avec la ténacité à la fracture. Sous le mode dynamique, les essais de résistance à la perforation ont été conduits en utilisant des forets pour le perçage des métaux (de type HSS) et pour la maçonnerie. Les rapports entre la charge appliquée et les aires de contact et de la section transversale (P/Ac et P/At respectivement) pour une profondeur h de la pointe du foret dans la surface des dépôts ont été utilisés pour calculer la dureté par perforation dynamique (HDD). Les résultats ont montré une bonne correspondance avec la micro dureté Vickers malgré la plus faible reproductibilité que ceux obtenus en mode statique. / Thermal sprayed ceramic coatings are highly used in application where high performance regarding to mechanical properties are required. Thus it is essential to determine the coatings’ mechanical properties (hardness, Young modulus and fracture toughness), which is made by classical indentation methods using Vickers, Knoop and Berkovich indenters. Those methods use sophisticated devices, rigorous sample preparation and demanding time processes in execution and data analysis that make them expensive and complicated in implementation. This research is focused tostudy the drilling resistance as an alternative method to measure the mechanical properties of atmospheric plasma spray ceramic coatings. For these purpose powders of six chemical compositions most widely used in industrial applications were employed as feedstock powders to manufacture coatings by atmospheric plasma spraying: Al2O3, TiO2, Al2O3-15wt % TiO2, Al2O3-43wt % TiO2, YSZ and Al2O3-YSZ. Physical, chemical and mechanical properties have been determined. Macro and micro hardnesses were determined by Vickers indentations, the Young’s modules werecalculated from Knoop micro hardness measurements and fracture toughness from Vickers micro hardness. Static drilling resistance tests were carried out with commercial drill bits used to perforate glass plotting the applied force (P). against the drill bit depth (h). Relationships between the applied force and the bit’s contact or cross sectional areas (P/Ac and P/At respectively) corresponding to the drilled depth (h) were used to set the Static Drilling Hardness (HDs).Furthermore, the slopes in the unloading stage corresponding to ΔP/ΔAc or ΔP/ΔAt were used to calculate the Static Drilling Elastic Modulus (Es). The HDs and Es results exhibit both well fit with the micro-hardness and Young modulus measurements made by classical methods and high reproducibility in the results. It was observed that cracks and spalling produced on the coatings surfaces during loading reduce the slope of the P vs h plot which could be used in future studies to correlate to the toughness of coatings. Dynamic drilling tests using bits to perforate metals (HSS) andmasonry were also carried out. The ratios between applied load and contact or cross sectional areas (P/Ac and P/At respectively) corresponding to the depth (h) of the hole drilled on each coating were used to calculate the Dynamic Drilling Hardness HDD which shows a good fit with the measured hardness on the surface of coatings realized by micro-indentation Vickers but lower reproducibility than those obtained with static drilling hardness results.

The Gray Fossil Site, Washington County, Tennessee, has produced a remarkable Mio-Pliocene fauna and flora with no known correlative in the Appalachian region. After its discovery in 2000, a series of auger holes were drilled by the Tennessee Department of Transportation (TDOT) to determine the areal extent of the site. Drilling indicated that the fossils occurred in fill material within a paleokarst basin, but the distribution of boreholes does not permit details of sinkhole topography, and therefore its formation and fill history, to be adequately resolved. To better image the sinkhole basin, a high-resolution gravity survey, which included 1104 gravity measurement stations, was conducted. These data were used to create complete Bouguer and residual gravity anomaly maps and a 3D density model via inversionmethods. The residual gravity anomaly map compares favorably with 29 TDOT auger holes drilled to basement, but contains significantly more detail. The residual gravity anomaly map reveals the presence of seven separate sinkholes. However, 3D inverse modeling constrained by drill-hole depths and density data indicates that there are 11 separate sinkholes formed within the Knox Group carbonates. These sinkholes, which range between 20 and 44 m in depth, are aligned along northwest and northeast trending linear features that correlate to structural features formed during the Appalachian orogenies. It is possible that the overall sinkhole basin formed as the result of partial coalescence of multiple sinkhole structures controlled by a joint system and that the sinkholes then acted as a natural trap for the Gray Fossil Site fauna and flora.

No description available.

Modern day oil & gas well costs are driven by drilling performance as time becomes the dominant capital expense source. The ability to lower drilling costs becomes paramount when tight economic margins and high uncertainties/risk exist. Penetration rate decreases drastically in ultra deep formations, and substantial time is spent drilling the deepest section of these wells. Therefore, significant cost savings may be obtained through an improvement in penetration rate in deep formations. This paper shows that in HTHP (High Temperature High Pressure) hard shale/sand environments that PDC (Polycrystalline Diamond Compact) bits paired with water based mud experience 88% improvement in penetration rate than those paired with oil based mud. With this improvement in drilling rate, well costs can be substantially reduced making future ultra-deep hydrocarbon accumulations economically producible. Also observed was a drastic decrease in penetration rate in PDC bits with oil base mud which led to the use of diamond impreg bits, as the water base with PDC still maintained respectable penetration rates. The conventional penetration rate controls are still applicable in this case, but there exists a fundamental difference between the rock/fluid interactions of each mud type. Bit type, operating conditions, formation characteristics, and bit hydraulics are shown to not be the dominant influencing factor of this performance trend. The water base fluids examined have higher filtrate rates than the oil base fluids. However, a consistent data set of increasing filtrate rate corresponding to increasing penetration rate cannot be derived. Therefore filtration characteristics remain as a possible and partial influencing factor behind this data. Future experimental research is needed to confirm or disprove this theory. At this time the actual cause of this behavior is unknown, however the trend has been established showing water base drilling fluids performance versus oil base in the HTHP/hard rock environment.