<p>Two methods for the measurement of micro-scale stressvariations of press felt surfaces were developed. The methodswere based on a thin plastic film that was coated with anopaque stress-sensitive layer (Cronapress conversion film). Thefilm was compressed between a felt and a smooth surface. Uponapplication of load the opaque layer became partiallytransparent at the locations where load was applied by thesurface fibres of the felt. The degree of transparency was afunction of the locally applied stress. The spatial resolutionof the method was 6.3 µm, which means that even details ofthe order of the diameter of a batt fibre diameter can beresolved.</p><p>Parameters characterising the stress variations were used toquantitatively describe the extent of the stress variations,the size of the contact areas and the distance between them.The applicability of these contact characterisation parameterswas evaluated in laboratory wet pressing experiments and inpilot paper machine trials for two sets of specially designedpress felts. In general, the dewatering result was mainlyinfluenced by the diameter of the felt surface batt fibres andby the web grammage. For a specific pulp type and operatingconditions a multivariate model was formulated based on themeasured web dryness, web grammage and each contactcharacterisation parameter. The model was able to describe thedewatering capability of the different felts tested. Contactcharacterisation parameters related to contact properties (e.g.contact area ratio) gave the best prediction for low grammagewebs, while parameters related to flow properties (e.g. size ofopenings) gave the best prediction for high grammage webs.</p><p>Furthermore it was found that at a certain web grammage, thesurface batt fibre diameter did not have an influence on thedewatering result. This grammage was termed "transitiongrammage". Below the transition grammage a fine surface gavesignificantly better dewatering, while the opposite trend wasobserved above the transition grammage. Based on these results,a modified dewatering hypothesis was formulated. Thishypothesis links the non-uniform compression of the wet webwith different dewatering situations for low and high grammagewebs.</p><p><b>Keywords</b>Press felts, Roughness, Smoothness, SurfaceStructure, Uniformity, Wet pressing, Batt fibre, Base weave,Stress variations, Micro-scale.</p>

In the evaluation of a slope for stability, it is important to determine useable values of various rack properties. One of the most important rock properties which must be determined is the internal angle of friction, Φ. Surface roughness can have a considerable effect upon the friction angle. The norm has been to adjust the friction angle for roughness by the average asperity angle, i, or to compensate by use of a Joint Roughness Coefficient. The objective of this investigation was to develop a method of mathematically quantifying rock discontinuity surface roughness without the need for a subjective determination based upon a visual comparison with some standard. This mathematical relationship then can be used in the evaluation process of the stability of a slope based upon the limit equilibrium concept. This investigation utilized the concept of fractal dimension to quantify the surface roughness along discontinuities in four rock types. It resulted in the development of a relationship between Joint Roughness Coefficient (JRC) and fractal dimension (D) for each of the four rock types of the form:(UNFORMATTED TABLE/EQUATION FOLLOWS): JRC(Pah) = -1002.11 + (1003.83)D, where: D(Pah) averages 1.00837. JRC(Dwd) = -995.58 + (996.92)D, where: D(Dwd) averages 1.00660. JRC(Min) = -925.47 + (927.90)D, where: D(Min) averages 1.00750. JRC(Met) = -1126.41 + (1127.84)D, where: D(Met) averages 1.00336.(TABLE/EQUATION ENDS)These equations for the relationship between JRC and D can be approximated by: JRC = 1000(D - 1). It was possible to substitute this approximate relationship into Barton's equation for shear strength of discontinuities. This resulted in a useable equation for peak joint shear strength which does not require a subjective determination of a "Roughness Coefficient". Instead, the fractal dimension of the discontinuity surface can be precisely mathematically determined. It was next possible to rewrite the equation for the factor of safety for the case of simple plane shear by substituting the equation for T(peak) into the limiting equilibrium equation. This then gave a method for estimating the factor of safety against sliding on a discontinuity given a measurement of the fractal dimension of the discontinuity surface.

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The background for this thesis originates from a study of the flow characteristics for an airfoil of the type NACA0018. The aim for this thesis was to evaluate how the characteristics of the flow over the NACA0018 profile depend on surface roughness. Airfoils were manufactured in Aluminum by Computer Numerical Control-milling and in polylactide polymer using a 3D-printer, where some of the profile surfaces were postprocessed with sandpaper in various grain sizes. The surface roughness of the profiles was evaluated in a 3D optical profilometer using white light interferometry from Filmetrics. By that technique 3D surface plots were created. The manufactured airfoils were tested in a wind tunnel where the achieved data was made dimensionless for comparative purposes. The computational fluid dynamics simulations were performed in Ansys Fluent and compared against the wind tunnel data as well as with the data from a previously made study at htw saar. The results from the wind tunnel tests show that the surface roughness has an effect on the flow characteristic of the airfoil, where different angles of stall were observed in the comparison. The difference for the dimensionless numbers coefficient of lift and drag show that the manufactured aluminum airfoil performs better compared to the 3D-Printed airfoil in this study. It has a higher performance mean value for both of these coefficients in a span of angles between 0 and 30 degrees. When compared, the results from the simulations and wind tunnel experiments do match in some cases, where the dimensionless coefficients and stall angle coheres. Further studies based on this report are recommended, where small geometric changes to the profile could be tested and validated.

Student Number : 0100281N - MSc(Eng) Research Report - School of Civil and Environmental Engineering - Faculty of Engineering and the Built Environment / Many environmental and engineering projects require prediction of the velocity of flow in river channels, in terms of those channel properties and flow characteristics which induce resisting forces or an energy loss to the flow. Relationships such as the Manning, Chézy and Darcy-Weisbach equations have been in use for a century or more. All of them account for resistance with a single coefficient of resistance, and the central problem is evaluation of this coefficient. Experimental results by different researchers have shown that Manning’s n varies strongly with the ratio of flow depth to roughness height. It is constant for values of this ratio above about 4, but increases significantly for lower values. This suggests that the equation is not suitable in its original form for the case of intermediate-scale roughness. The roughness is intermediate-scale if the relative submergence ratio of flow depth to roughness elements height lies between 1 and 4. The influence of the roughness elements on flow resistance in this regime is caused by a combination of both element drag and boundary shear, or friction. The results of an experimental study with hemispherical roughness elements are presented, showing how the roughness element size, spacing and pattern influence flow resistance. For the range of conditions tested, Manning’s n appears to depend on roughness element size, spacing and pattern.

O presente estudo teve como objetivo avaliar quantitativamente a alteração na rugosidade superficial e o desgaste de resinas compostas com diferentes características de matriz orgânica e de carga inorgânica frente ao teste de escovação simulada e ciclagem de pH. Foram testadas três resinas compostas: Filtek Z250 (Bis-GMA, microhíbrida), Filtek Z350 (Bis-GMA, nanoparticulada) e Filtek P90 (silorano, microhíbrida)(3M-ESPE). Para cada resina foram confeccionados dois grupos (n=10) de corpos de prova retangulares (15mmx5mmx4mm). Após a polimerização e polimento adequado dos espécimes, a rugosidade inicial (Ra) foi obtida pela média de três leituras com o Rugosímetro Hommel T1000. Metade de cada corpo de prova foi protegida com esmalte de unha e um dos grupos de cada resina foi submetido a um protocolo de ciclagem de pH (desmineralização-pH 4,3 e remineralização-pH 7,0). Para o teste de abrasão foram realizados 100.000 ciclos de escovação simulada, permanecendo a metade protegida como grupo controle. Na metade escovada foi verificada a rugosidade final, seguindo os mesmos parâmetros iniciais, e o desgaste (µm) foi quantificado pela média de 3 leituras do perfil real abrangendo as duas superfícies (controle e escovada). Os resultados obtidos (ANOVA, teste t Student e Tukey, p<0.05) mostraram diferenças significantes para o desgaste e alteração de rugosidade entre as resinas testadas. A maior média de desgaste foi apresentada pela Filtek P90 (11,505µm±5,690) com diferença significante para a Filtek Z250 (4,191µm±1,725) e para a Filtek Z350 (4,163µm±0,947), sendo que a ciclagem de pH afetou apenas o desgaste da resina Filtek P90 (15,305µm±5,409). Verificou-se aumento da média de rugosidade superficial para as resinas Filtek Z250 e Z350 após escovação simulada, enquanto que a resina Filtek P90 apresentou comportamento contrário, com diferenças estatisticamente significantes (p<0,05). As imagens de microscopia eletrônica de varredura apresentaram-se coerentes com os resultados quantitativos obtidos. / The present study aimed to quantitatively evaluate the surface roughness alteration and wear of resin composites with different characteristics of organic matrix and inorganic filler when submitted to simulated toothbrushing abrasion and pH cycling. Three different resin composites were evaluated: Filtek Z250 (Bis-GMA, microhybrid), Filtek Z350 (Bis-GMA, nanofilled) and Filtek P90 (silorane based, microhybrid) (3M-ESPE). For each resin two groups (n=10) of rectangular specimens (15mmX5mmX4mm) were made. After polymerization and polishing, the initial roughness (Ra) was evaluated by the average of three tracings using a roughness tester Hommel T1000 basic. Half of each specimen was protect with nail varnish and one group of each resin was submitted to pH cycling (demineralization-pH 4,3 and remineralization-pH 7,0). For the abrasion test 100.000 strokes of simulated toothbrushing was processed. The protected side was maintained as control. Over the brushed side the final roughness was measured with the same initial parameters and wear was quantified by the average of 3 readings of the real profile between the two surfaces (control and brushed side). The obtained results (ANOVA, Student t test and Tukey, p<0.05) showed significant differences of wear and surface roughness alteration between the tested materials. Filtek P90 presented the highest average wear rate (11.505 ± 5.690µm) compared to Z250 (4.191 ± 1.725µm) and Z350 (4.163 ± 0.947µm) and the pH cycling significantly affected the wear of Filtek P90(15.305 ± 5.409 mM). The surface roughness evaluation revealed an increasing on surface roughness for Filtek Z250 and Filtek Z350 after toothbrushing, while Filtek P90 showed an opposite behavior, with statistically significant differences (p<0.05). The scanning electron microscope images were in accordance to the quantitative results obtained.

Les aspérités géométriques d'un plan de faille contrôlent en partie toutes les étapes de la rupture sismique, depuis sa nucléation jusqu'à l'arrêt du séisme. L'objectif de ce travail est de caractériser la morphologie des surfaces de faille sur la large gamme d'échelles spatiales impliquées dans les tremblements de terre, puis d'explorer son influence sur l'organisation spatiale du glissement et des contraintes. L'approche utilisée inclue des observations de terrain couplées à une étude numérique et théorique. La combinaison de méthodes récentes de mesures topographiques (LiDAR, rugosimètre laser, interféromètre à lumière blanche), qui couvrent des gammes d'échelles spatiales complémentaires, permet de proposer un modèle géométrique cohérent de cinq zones de failles étudiées (Alpes françaises, Apennins, Turquie, Californie, Nevada). La rugosité des surfaces de failles montre des propriétés de dépendance d'échelle, et plus précisément suit un régime auto-affine anisotrope (l'exposant de rugosité est Hpara = 0.6 dans la direction du glissement et Hperp = 0.8 dans la direction perpendiculaire) depuis la centaine de micromètres jusqu'à plusieurs dizaines de mètres. En complément, l'analyse de la rugosité des ruptures de surface de huit tremblements de terre continentaux majeurs montre qu'un unique régime auto-affine anisotropique et sans longueur caractéristique est maintenu jusqu'à l'épaisseur de la croute sismogénique. Cette description de la géométrie des surfaces de failles et des traces de ruptures, est indépendante du contexte géologique. Plus particulièrement, cette étude met en avant que dès lors qu'un glissement cumulé métrique est atteint sur une faille, la complexité géométrique des portions actives des zones de failles est maintenue quel que soit le déplacement supplémentaire accommodé. Finalement, motivé par des observations de terrain, il est proposé que le processus dominant à l'origine de la rugosité des surfaces de failles puisse être l'interaction mécanique et la coalescence de segments multi-échelles. Deux conséquences émergent de cet état de rugosité. Les distributions spatiales du champ de glissement d'une part et du champ des contraintes lors d'un tremblement de terre d'autre part peuvent être expliquées par la présence de deux interfaces rugueuses auto-affines pressées élastiquement et cisaillées. Notamment, en utilisant un modèle numérique de propagation d'une rupture sur une interface hétérogène, la corrélation entre la rugosité 3-D des failles et la distribution spatiale 2-D du glissement dans le plan est clarifiée. Il est proposé que les hétérogénéités spatiales du glissement visibles sur les modèles cinématiques de rupture sismique soient préférentiellement dominées par les complexités géométriques locales plutôt que par la dynamique du front de rupture lui-même. Par ailleurs, les propriétés auto-affines des lèvres de la faille impliquent que les fluctuations spatiales de la chute de contrainte lors d'un séisme augmentent vers les courtes longueurs d'ondes ; ce qui est confirmé par des observations sismologiques. En considérant un modèle de rupture en cascade, il est alors probable que les failles sont fortement inhomogènes, avec des grands tremblements de terre composés d'une somme de petites aspérités multi-échelles qui subissent de fortes chutes de contrainte. Cette étude met en lumière l'importance des hétérogénéités locales en contrainte et en glissement dans la mécanique des tremblements de terre, et propose de les relier à des propriétés morphologiques self-affines de la surface de faille. / Geometrical asperities on fault planes partially control all stages of earthquake genesis, from the nucleation of a rupture, to its arrest. The present study aims at characterizing the geometrical morphology of fault surfaces on the wide range of spatial length scales involved in earthquakes, and exploring its influence on the spatial organization of slip and stresses during an earthquake. The approach combines field observations, numerical analysis and theory. Using recent methods of high resolution topographic measurements (LiDAR, laser profilometer, white light interferometer), spanning complementary ranges of spatial length scales, a consistent geometrical model emerges for the five fault zones (French Alps, Apennines, Turkey, California, Nevada) studied here. The morphology of the fault surface, i.e. its roughness, is scale dependent, and more specifically follows a self-affine anisotropic regime (the roughness exponent is Hpara = 0.6 in the slip direction and Hperp = 0.8 perpendicular to it) from the scale of hundred of micrometers to several tens of meters. In addition, the roughness analysis of the surface rupture of height major continental earthquakes shows that a single self-affine regime is maintained up to the thickness of the seismogenic crust, without any characteristic length scale. This description of the geometry of the fault scarps and rupture traces is independent of the geological context. More particularly, this study highlights that once a fault has achieved a cumulated a small offset no larger than one meter, the roughness of the active portion of the fault zone is maintained even if further slip is accommodated. Finally, motivated by field observations, it is proposed that the main process causing the roughness of fault surfaces can be the mechanical interaction and coalescence of multi-scale segments. Based on a numerical and theoretical approach, the spatial distribution of both the slip and stress fields during an earthquake can be understood by the presence of two self-affine rough interfaces elastically squeezed and sheared. Using a numerical model of rupture propagation on a heterogeneous interface, the link between the 3-D fault roughness and the 2-D spatial distribution of the slip is clarified. It is proposed that the spatial heterogeneity of the slip observed on kinematic models of earthquake rupture is preferentially dominated by the local geometrical complexity rather than the dynamic of rupture itself. Moreover, the self-affine properties of the fault interfaces imply that the spatial fluctuations of the stress drop after a rupture event increase towards shorter wavelengths. Considering a rupture cascade model, it is likely that the faults may be considered as highly inhomogeneous with large earthquakes composed by a sum of multi-scales ruptures of small asperities with large stress drop within an average fault surface with small stress drop. This study emphasizes the importance of local stress and slip heterogeneities on the mechanics of earthquakes and proposes to relate these parameters to the self-affine morphology of the fault surfaces.

Surface metrology has been widely used in manufacturing for many years. There has been a wide range of techniques applied for measuring surface topography. A photometric stereo technique is one of the best ways for the analysis of three-dimensional (3D) surface textural patterns. Many published works are concerned the developed approach for recovering the 3D profiles from surface normal. This research not only presents a methodology used to retrieve the profiles of surface roughness standards but also investigates the uncertainty estimation of textural measurement determined by the photometric stereo method. Various input quantities have been studied such as pixel error from recovered 3D surface textural patterns, the power of light source which involved with surface roughness average (Ra) value and the effect of room temperature. The surface roughness standards were utilized as the reference value. In term of increasing accuracy of the reference value, a contact method (stylus instrument) was used to calibrate them. Illumination angles of light source had some influence on the measurement results. A coordinate measuring machine (CMM) was used for holding the light source in order to study the effects of tilt and slant angles. The effect of tilt and slant angles were investigated. The results of these experiments successfully indicated that the angle used in photometric stereo method played an important role to the accuracy level of the roughness measurement results. The surface roughness specimen manufactured by a Computer Numerical Control (CNC) was applied to validate the capability of the photometric stereo system.

With an increasing number of transport operators seeking permits to operate nonstandard or purpose-built vehicle types, information is required to assist road authorities to determine which vehicle types could operate on the road network without compromising the safety of other road users. A project was created by ARRB TR to develop guidelines for determining route access for heavy vehicles. This project was developed in conjunction with the state road authorities, the National Road Transport Commission and the transport industry to obtain an understanding of the road space requirements for a range of common vehicle types. This project is the subject of this thesis. Two series of field experiments were conducted with six common heavy vehicle types on public roads west of Parkes NSW. Information collected during these full-scale experiments was used to increase the knowledge of the dynamic behaviour of these vehicles and to develop model route access guidelines. Data obtained from these field experiments also provided information to validate computer models and simulation outputs. This thesis showed that: 1) There was experimental evidence to demonstrate that vehicle lateral movement is excited by differences in vehicle wheelpath profiles (point-by-point pavement crossfall), which make a contribution to trailing fidelity (swept width), offtracking and swept path; 2) Vehicle type and speed are prime influences on the lateral movement of the rear trailer and therefore an important input into the model route access guidelines. Notwithstanding the practical and safety implications of applying different speed limits for various vehicle types, speed is a prime contributor to vehicle lateral movement and should be considered when determining route access; 3) Limited lateral position information suggested that one driver of two vehicle types position the vehicles so that the tyres on the rear trailer track on the sealed pavement and not on the pavement shoulder; 4) Based on a statistical analysis of the data obtained from the small sample which only considered the average crossfall of each test section the relative importance of the key parameters was (highest to lowest), IRI, vehicle speed and vehicle type. It was shown that good estimates of lateral movement can be obtained using a double integration technique of the measured lateral acceleration, without applying compensation for the trailer roll or the pavement crossfall. It is recommended that route access guidelines be developed using the lateral performance of a larger sample of vehicles in each class of heavy vehicles operating over a larger range of road types. The route access guidelines should contain a matrix of information on vehicle type/length, pavement condition roughness/profile and lane width. This would provide operators and regulators with a desk-top assessment tool for determining route access.