Thesis (M.S.)--University of Michigan, Ann Arbor, 1976. / Typescript (photocopy). Includes bibliographical references (leaves 48-49). Also issued in print.

Thesis (M.S.)--University of Michigan, Ann Arbor, 1976. / Typescript (photocopy). eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 48-49).

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<p>The cylinder liners’ surface is really important in an engine because it corresponds with piston rings to a tribologic system indispensable to know for reasons of wear, of oil consumption and engine’s life time. For these reasons, it is important to measure and characterize these surfaces.</p><p>The first part of the project is the observation of the impact of the number of strokes of the plateau honing on the surface of the cylinder liners. It is interesting to observe the impact of the variation of the number of strokes of the plateau honing on the peaks, plateaus and valleys of the surface.</p><p>The second part of the project is the simulation of the oil flow on the surface to observe the links between the roughness parameters and the oil flow and the shear stress.</p><p>The results are interesting, we will observe that the number of strokes of honing as a good impact on the quality of the surface.</p><p>In the second part of the project, the results show a correlation between the machining parameters and the roughness and functional parameters.</p><p>It could be interesting to mix the two parts of the project to see the correlation among machining, roughness and functional parameters for the samples made in the first of the project.</p>

The cylinder liners’ surface is really important in an engine because it corresponds with piston rings to a tribologic system indispensable to know for reasons of wear, of oil consumption and engine’s life time. For these reasons, it is important to measure and characterize these surfaces. The first part of the project is the observation of the impact of the number of strokes of the plateau honing on the surface of the cylinder liners. It is interesting to observe the impact of the variation of the number of strokes of the plateau honing on the peaks, plateaus and valleys of the surface. The second part of the project is the simulation of the oil flow on the surface to observe the links between the roughness parameters and the oil flow and the shear stress. The results are interesting, we will observe that the number of strokes of honing as a good impact on the quality of the surface. In the second part of the project, the results show a correlation between the machining parameters and the roughness and functional parameters. It could be interesting to mix the two parts of the project to see the correlation among machining, roughness and functional parameters for the samples made in the first of the project.

With the continual challenges associated with reducing aircraft engine noise, there is need for acoustic liner configurations that target broadband performance. This thesis experimentally and analytically investigates passive noise control methods to improve broadband frequency attenuation through various acoustic liner designs. The inclusion of acoustic metamaterials within these liners is examined and optimized. The metamaterials studied consist of resonant and non-resonant materials which include porous foams, microperforated plates (MPP), and embedded aluminum masses. Through finite element analysis, the understanding of the physics behind acoustics as well as aeroacoustics inspire their design. Sensitivity studies on the overall liner shape, facesheet properties, poro-elastic material properties, MPP's, as well as size and placement of embedded masses assist in successfully achieving broadband attenuation. Within the finite element study, an optimization tool will provide additional assistance in quantifying critical system parameters within the designs by minimizing the sum of the transmitted sound intensity over the design frequency bandwidth and hence maximizing attenuation. Broadband frequency absorption and attenuation is successfully achieved within the frequency range of 400-2600 Hz through the design of a varying depth optimized acoustic liner as well as a metamaterial-inspired liner. / Master of Science

Actuellement, les turboréacteurs sont les principales sources de bruits d’un avion. Afin de supprimer cette source de bruit qui est très incommodante pour l’environnement, les ingénieurs ont conçu durant ces trente dernières années des matériaux permettant de réduire l’émission de bruit provenant des turboréacteurs. Ces matériaux communément appelés liners sont pour l’instant relativement efficaces. Afin de contrôler la qualité de fabrication des liners, l’instigateur du projet Pratt & Whitney Canada (PWC) veut caractériser ces traitements acoustiques en mesurant leur impédance acoustique en tenant compte des conditions réelles de champ acoustique et des conditions aérodynamiques. C’est ainsi qu’a pris naissance mon projet de maîtrise portant sur la conception et la fabrication d’un banc de mesure en vue de la caractérisation de ces liners. En premier lieu, une amélioration de la méthode de caractérisation géométrique et acoustique des liners au niveau de la nacelle du turboréacteur (in situ) a été apportée. En effet, une méthode de mesure par imagerie a été élaborée pour mesurer le taux de perforation et le diamètre de perforation d’un liner au sein même de la nacelle. D’autre part, les fuites acoustiques au sein du tube d’impédance in situ de PWC ont été éliminées. Par ailleurs, une méthode de mesure in situ de l’impédance des liners a été établie. En second lieu, un banc d’essai a été conçu et fabriqué pour mesurer, par méthode inverse, l’impédance des liners sous incidence rasante. Divers matériaux ont été testés afin de valider le banc. Les résultats expérimentaux sont bien proches des résultats numériques. Nous n’avons pas abouti à la partie considérant l’écoulement vu la limitation de puissance de la soufflerie du GAUS néanmoins le concept théorique et la méthode de mesure expérimentale restent bien valables dans le cas d’un écoulement. Nous avons choisi une soufflante pour générer l’écoulement dans le banc et cette partie sera traitée par un autre étudiant.

Research Doctorate - Doctor of Philosophy (PhD) / Consolidation of clayey contaminant barriers, such as are employed as landfill liners, has been postulated as a cause of accelerated transit of contaminants and hence their earlier than expected appearance in secondary leachate. This proposition is theoretically investigated in this thesis using a novel large-deformation, one-dimensional continuum model of coupled mechanical consolidation and solute transport. The model is a generalization of existing coupled consolidation and solute transport models described in the literature. It takes into account both non-linearities in geometry as well as material constitutive relations. The latter relate the compressibility, hydraulic conductivity and effective diffusion coefficient to the deformation of the soil. In addition to providing details of the governing equations and constitutive relations, a detailed derivation of the three classical one-dimensional consolidation boundary conditions, i.e. undrained top and drained bottom, drained top and undrained bottom, drained top and bottom is also given. From the continuum model formulation, a numerical model was developed using proprietary finite element software – FEMLAB 2.3. The numerical model is verified by comparing results with those produced from other recently developed consolidation – transport models. In the course of conducting these comparisons, some results from a recent modelling investigation indicating that a twenty-fold reduction in the transit time of contaminants across a composite soil – geomembrane barrier may be possible were re-examined. This comparison reveals some apparent errors in the original analysis and indicates that the predicted large acceleration of contaminant transport induced by consolidation is probably unrealistic. The model is subsequently applied to a case study of a clay liner and geomembrane system. Results obtained are compared with those from various simplified models, including a “diffusion-only” (i.e. a rigid soil) model traditionally used in contaminant barrier design. For barriers incorporating low compressibility soils (such as well compacted clays), there is little difference between contaminant transit times predicted by the two models. However, for contaminant barriers incorporating more compressible soils, consolidation is shown to be capable of accelerating transport. These results indicate the potential importance of accounting for the effects of soil consolidation and they highlight some limitations of existing models when modelling solute transport through composite barriers utilizing soft soils. Based on these limited results, a way of taking into account soil consolidation using simplified models is suggested. In the penultimate chapter of this thesis, an extensive parametric sensitivity analysis of coupled consolidation and solute transport in composite contaminant barrier systems is presented. The analysis incorporates results of more than 3000 simulations for various combinations of barrier thickness, waste loading rate, initial void ratio, compression index, hydraulic conductivity and dispersion coefficient. Results are succinctly presented using dimensionless plots, which allow the comparison of results for a large number of parameter values, and hence, the clear identification of the most important factors affecting contaminant transport through a consolidating composite barrier system. The results demonstrate that there exists a pessimum rate of consolidation for which the contaminant transit time is minimised. In cases of extremely high barrier compressibility it is shown that an order of magnitude reduction in contaminant transit time may arise due to coupling between solute transport and consolidation. For barriers of low compressibility and porosity, such as well-engineered composite compacted clay landfill liners, it is found that the contaminant transit time is far less affected, though it may still be reduced by up to 30%. In general, the results suggest that the use of a coupled consolidation–contaminant transport model may be required for informed and conservative contamiant barrier design, especially if relatively compressible earthen components are utilised.

This research evaluated the use of geosynthetic clay liners (GCLs) as a potential barrier material to the migration of metals that are leached from mine waste. This thesis consists of two parts. In the first part, micro analytical methods including µXRD with synchrotron-generated µXRF elemental mapping and synchrotron-based µXRD (S-µXRD) were used to characterize the GCL bentonite and distinguish how mechanisms of metal attenuation could be identified. These analytical methods were of particular use for the clay material as they offer non-destructive, in situ investigation of various soil characteristics with microspatial resolution. The combination of the analytical methods allowed for identification of minerals such as gypsum and pyrite, not accessible by conventional methods. In particular, distinguishing accessory crystalline phases present in the “starting material” bentonite from those formed as a result of interaction with metal-bearing leachates is critical, as the development of metal-attenuating crystalline phases can have a significant long-term impact on metal mobility. In the second part of the thesis, the migration behaviour of metals (As, Al, Cd, Cu, Fe, Mn, Ni, Sr, and Zn) was investigated by means of diffusion tests and permeation experiments using four metal-containing waters: acidic rock drainage (ARD), lime-treated ARD, water from gold mine tailings, and landfill leachate with metal loading. Effective diffusion coefficients of the metals were calculated by modelling laboratory diffusion and sorption data. Water pre-hydrated GCLs were permeated with 15-21 pore volumes (PVs) of solution and their interaction with these solutions was examined in terms of both the hydraulic conductivity and the change in the geochemical characteristics of the permeant over time. The greatest increase in hydraulic conductivity occurred for the acidic rock drainage, where it increased from 1.6x10-11 m/s to 1.3x10-10 m/s following 21 PVs of permeation; still a very low value when compared to regulatory standards for clay barrier materials. Observed delayed breakthrough curves were indicative of the GCL’s strong attenuation capacity for a number of metals. An understanding of mechanisms of metal retention at both the micro and macro-scale levels will facilitate effective pollution prevention using GCLs. / Thesis (Ph.D, Civil Engineering) -- Queen's University, 2009-04-26 18:46:23.02

Research Doctorate - Doctor of Philosophy (PhD) / Consolidation of clayey contaminant barriers, such as are employed as landfill liners, has been postulated as a cause of accelerated transit of contaminants and hence their earlier than expected appearance in secondary leachate. This proposition is theoretically investigated in this thesis using a novel large-deformation, one-dimensional continuum model of coupled mechanical consolidation and solute transport. The model is a generalization of existing coupled consolidation and solute transport models described in the literature. It takes into account both non-linearities in geometry as well as material constitutive relations. The latter relate the compressibility, hydraulic conductivity and effective diffusion coefficient to the deformation of the soil. In addition to providing details of the governing equations and constitutive relations, a detailed derivation of the three classical one-dimensional consolidation boundary conditions, i.e. undrained top and drained bottom, drained top and undrained bottom, drained top and bottom is also given. From the continuum model formulation, a numerical model was developed using proprietary finite element software – FEMLAB 2.3. The numerical model is verified by comparing results with those produced from other recently developed consolidation – transport models. In the course of conducting these comparisons, some results from a recent modelling investigation indicating that a twenty-fold reduction in the transit time of contaminants across a composite soil – geomembrane barrier may be possible were re-examined. This comparison reveals some apparent errors in the original analysis and indicates that the predicted large acceleration of contaminant transport induced by consolidation is probably unrealistic. The model is subsequently applied to a case study of a clay liner and geomembrane system. Results obtained are compared with those from various simplified models, including a “diffusion-only” (i.e. a rigid soil) model traditionally used in contaminant barrier design. For barriers incorporating low compressibility soils (such as well compacted clays), there is little difference between contaminant transit times predicted by the two models. However, for contaminant barriers incorporating more compressible soils, consolidation is shown to be capable of accelerating transport. These results indicate the potential importance of accounting for the effects of soil consolidation and they highlight some limitations of existing models when modelling solute transport through composite barriers utilizing soft soils. Based on these limited results, a way of taking into account soil consolidation using simplified models is suggested. In the penultimate chapter of this thesis, an extensive parametric sensitivity analysis of coupled consolidation and solute transport in composite contaminant barrier systems is presented. The analysis incorporates results of more than 3000 simulations for various combinations of barrier thickness, waste loading rate, initial void ratio, compression index, hydraulic conductivity and dispersion coefficient. Results are succinctly presented using dimensionless plots, which allow the comparison of results for a large number of parameter values, and hence, the clear identification of the most important factors affecting contaminant transport through a consolidating composite barrier system. The results demonstrate that there exists a pessimum rate of consolidation for which the contaminant transit time is minimised. In cases of extremely high barrier compressibility it is shown that an order of magnitude reduction in contaminant transit time may arise due to coupling between solute transport and consolidation. For barriers of low compressibility and porosity, such as well-engineered composite compacted clay landfill liners, it is found that the contaminant transit time is far less affected, though it may still be reduced by up to 30%. In general, the results suggest that the use of a coupled consolidation–contaminant transport model may be required for informed and conservative contamiant barrier design, especially if relatively compressible earthen components are utilised.