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Wiedeman, Christopher William. "The Carnal Slip." VCU Scholars Compass, 2006. http://scholarscompass.vcu.edu/etd_retro/167.
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The thesis exhibit installed at VCU's Anderson Gallery was carried out using still imagery (a photograph), moving imagery (recorded video, live video), constructed objects and a delineated space. It was an experiment dealing with how one comes to know the world by virtue of one's physical activity within it. It was most importantly a work that required the viewer's participation in order to become "complete".
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Fortier, Alicia Elena. "Numerical Simulation of Hydrodynamic Bearings with Engineered Slip/No-Slip Surfaces." Thesis, Georgia Institute of Technology, 2004. http://hdl.handle.net/1853/4929.
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The no-slip boundary condition is the foundation of traditional lubrication theory. It says that fluid adjacent to a solid boundary has zero velocity relative to that solid surface. For most practical applications the no-slip boundary condition is a good model for predicting fluid behavior. However, recent experimental research has found that for special engineered surfaces the no-slip boundary condition is not applicable. Measured velocity profiles suggest that slip is occurring at the interface. In the present study, it is found that judicious application of slip to a bearings surface can lead to improved bearing performance.
The focus of this thesis is to analyze the effect an engineered slip/no-slip surface could have on hydrodynamic bearing performance. A heterogeneous pattern is applied to the bearing surface in which slip occurs in certain regions and is absent in others. Analysis is performed numerically for both plane pad slider bearings and journal bearings. The performance parameters evaluated for the bearings are load carrying capacity, side leakage rate and friction force. Fluid slip is assumed to occur according to the Navier relation and the effect of a critical value for slip onset is considered.
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Sentmanat, Martin Lamar. "Design and evaluation of a slit die rheometer to study wall slip." Thesis, McGill University, 1992. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=61100.
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Extrudate distortion is a problem that often limits production rates in certain commercial processes such as film blowing and it has been suggested that slip in the die land plays an important role in this phenomena. It has been hypothesized that during slip flow in a die neither the wall shear stress nor the slip velocity is constant along the length of the die. For this reason, a slit die rheometer was developed to monitor directly the shear stress distribution of a molten polyethylene by means of two shear stress transducers mounted at different axial locations along the length of the slit. Previous transducers used at McGill do not perform well at high pressures. Therefore, a new disk-bar shear stress transducer was designed for use at high pressure. However, experimental evaluation of the slit die rheometer suggests that the large pressure gradient present in the slit affects the operation of this transducer. It is hypothesized that the pressure gradient across the active face of the shear stress transducer and the disk element impose a torque opposite to that of the applied shear stress on the active face. This pressure gradient effect was unanticipated because no shear stress transducer has ever been used in a pressure driven flow. Before the research on wall slip can proceed a new shear stress transducer that is unaffected by either high pressure or large pressure gradients must be developed. Possible ways of meeting this need are proposed.
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Kaneda, Heitaro. "Detection of Active Low Slip-Rate Strike-Slip Faults and Their Paleoseismicity." 京都大学 (Kyoto University), 2004. http://hdl.handle.net/2433/147787.
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Smith, Elizabeth Therese. "Slip table dynamic behavior." Thesis, Massachusetts Institute of Technology, 1995. http://hdl.handle.net/1721.1/49941.
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Hack, Thorsten. "Stick-slip piezoelectric actuators." Thesis, University of Cambridge, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.624403.
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Xu, Guoda, John M. Bartha, Stuart McNamee, Larry Rheaume, and Allen Khosrowabadi. "OPTICAL SLIP-RING CONNECTOR." International Foundation for Telemetering, 1999. http://hdl.handle.net/10150/607336.
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International Telemetering Conference Proceedings / October 25-28, 1999 / Riviera Hotel and Convention Center, Las Vegas, NevadaCurrent ground-based tracking systems at the DoD test and training ranges require transmission of a variety of signals from rotating platform to fixed control and process center. Implementation of commercial off the shelf (COTS) solution for transmitting high-speed, multiple-channel data signals over a rotational platform prompt the development of an advanced electro-optic hybrid rotating-to-fixed information transmission technology. Based on current demand, an Air Force-sponsored Small Business Innovative Research (SBIR) contract has been awarded to Physical Optics Corporation (POC) to modify existing tracking mounts with a unique electro-optic hybrid rotary joint (EOHRJ). The EOHRJ under current development is expected to provide the following features: 1) include a specially designed electrical slip-ring, which is able to accommodate hundreds of transmission channels, including electrical power, control, feedback, and low-speed data signals; 2) include an optical fiber slip-ring which, by incorporating with electrical time division mulitplexing (TDM) and optical wavelength division multiplexing (WDM) technologies, is able to provide multiple channel, high data rate (over gigabits per second), and bi-directional signal transmission; and 3) is designed to be reliable for harsh environmental operation, adaptive to stringent size requirement, and accommodating to existing electrical and mechanical interfaces. Besides the military use, other possible commercial applications include on board monitoring of satellite spinners, surveillance systems, instrumentation and multi spectral vision systems, emergency/medical instruments, remote sensing, and robotics.
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Mak, Hong-man Herman, and 麥匡文. "Effective slip due to Stokes flow through channels with patterned stick-slip walls." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2011. http://hub.hku.hk/bib/B47153970.
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This thesis comprises studies of two problems on Stokes flows through (i) a plane microchannel, and (ii) a microscale circular capillary tube, of which the walls are superhydrophobic surfaces featuring micro- or nano-patterns. In the first problem, an analytical study on longitudinal and transverse flows through a plane microchannel, which is made up of a periodic array of ribs and grooves on the upper and lower walls, is performed. This study focuses not only on the Cassie state, but also on the state whereby the liquid is allowed to penetrate the grooves between the ribs. These grooves are filled with inviscid gas and this periodic array gives rise to heterogeneous boundary conditions for the flow. Partial-slip and shear-free conditions are applied on the solid–liquid interface and the liquid–gas interface, respectively. Using the methods of eigenfunction expansions and domain decomposition, semi-analytical models are developed for four different settings. Two of them correspond to longitudinal flow with in-phase and 180-out-of-phase alignments of ribs between the upper and lower walls. The other two are for transverse flow with the in-phase and out-of-phase wall alignments. These models enable the effective slip lengths, normalized by half the pitch of the pattern, to be deduced as functions of the channel height, the microscopic or intrinsic partial slip length, the depth of liquid penetration, and the width of the grooves or the shear-free area fraction of the liquid-gas interface. Numerical calculations are performed to examine effects of these parameters on the effective slip length. The effect of the phase of alignment of ribs is appreciable when the surface is in the Cassie state and the channel height is sufficiently small. In-phase alignment yields a larger effective slip length in longitudinal flow. In sharp contrast, out-of-phase alignment is preferable in transverse flow. In the case involving penetration, a larger liquid penetration can give rise to a larger slip length in a thin channel.
In the second problem, an analytical study on flow through a microscale circular tube, of which the wall is patterned with a periodic array of spots or holes, is performed. Void region is filled with inviscid gas and patterns of circular and square shapes are considered. For simplicity, liquid penetration into the cavities is not considered, and hence the focus is on the Cassie state. No-slip and shear-free conditions are applied on the solid–liquid interface and the liquid–gas interface, respectively. By the methods of eigenfunction expansions and point collocation, a semi-analytical model is established. The effective slip length, normalized by the tube radius, is found as a function of the pitch of the pattern in the streamwise direction, the number of periodic units in the circumferential direction, and the solid fraction. Comparisons with some proposed scaling laws, varying pitch, solid fraction and tube size are performed. Large slip length is produced by arranging small circular no-slip spots with large separation in the streamwise direction. In some situations, spots and holes can be replaced by parallel stripes to increase the slip length.published_or_final_version
Mechanical Engineering
Master
Master of Philosophy
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Amey, Ruth Mary Joy. "The fractal nature of fault slip and its incorporation into earthquake slip inversions." Thesis, University of Leeds, 2018. http://etheses.whiterose.ac.uk/22137/.
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In order to understand how earthquakes nucleate, propagate and terminate it is essential to understand the properties and stress conditions of the surfaces upon which earthquakes occur. Fault surfaces control frictional properties and by measuring exhumed faults we can better understand earthquake propagation and how this may be linked to fault structure. In order to forecast areas of a fault likely to be at risk from future failure it is necessary to accurately model the slip that occurs during each measured earthquake. In recent years many lines of evidence suggest that fault surfaces and earthquake slip show fractal properties. This includes high resolution scans of fault surfaces, observations of coseismic surface slip and analysis of published slip distributions. In this thesis I investigate how fault structure may affect the fractal properties of fault surface roughness, by investigating the along-strike changes in properties of the Campo Felice fault in the Italian Apennines. I then incorporate observations of fractal properties into earthquake slip inversions through a new form of regularisation, which I develop using Bayesian methods. Through this I aim to improve our understanding of the surfaces upon which earthquakes occur, how this links to fault structure and to improve our coseismic slip models, that provide the basis of stress models and hazard analysis. Fault surfaces displaying fractal properties mean that there is a power-law relationship between the topography of a fault and the wavelength of this topography: the magnitude of height fluctuations depends upon the scale at which they are observed. Whilst many studies have investigated fault roughness properties, here I present the first study of how fault roughness varies along the strike of a fault. I use terrestrial laser scans and laser profilometer scans at 14 locations along the length of the Campo Felice normal fault in the Italian Apennines, as well as a scan encompassing several hundred meters along the length of the fault. These scans show that the Campo Felice fault displays fractal properties over at least six orders of magnitude perpendicular to slip and at least three orders of magnitude parallel to slip. But, contrary to previous findings on other faults, I find that the Hurst parameter, which controls the fractal nature of the fault surface, changes considerably and unpredictably along the length of the fault, even between observations tens of metres apart. I suggest that this variability may be due to the variation of slip vector along the length of the fault, as is frequently observed in earthquakes. This variability could, additionally, be linked to fault asperities halting or impeding rupture, such that some areas of the fault experience more earthquakes, or experience different stress conditions during the same earthquake. I also find that the magnitude of topography displayed by Campo Felice fault is low compared to previous studies, suggesting it may be at risk of larger earthquakes. Observations of fractal fault surfaces suggest that earthquake slip should be fractal too. By using geodetic data taken at the surface before and after an earthquake we can perform slip inversions to give a model of how much slip occurred underground, on the fault surface. This is routinely performed for large, continental earthquakes. Due to noise and lack of data these inversions are frequently regularised to produce a stable solution, but the standard regularisation techniques have little physical basis. I incorporate fractal properties of earthquake slip into slip inversions by introducing a new regularisation technique: von Karman regularisation. I use a Bayesian method to fully explore parameter space and better understand uncertainties on the model parameters. From synthetic tests I find that this regularisation performs comparably, if not better, than other frequently used methods upon both fractal and Laplacian input slip distributions. Using InSAR (Interferometric Synthetic Aperture Radar) and GPS (Global Positioning System) data from the 2014 Mw 6.0 Napa Valley earthquake, I invert for slip using a two-segment fault model. I find that the choice of regularisation changes the location and magnitude of slip, which could have important implications for stress transfer and our understanding of the so-called shallow slip deficit. Through its incorporation of fractal properties, von Karman regularisation represents a more physical regularisation of earthquake slip along a fault plane. However, some bias can be introduced by incorrectly choosing the length and width of the fault plane. If a fault plane is too large, the regularisation can cause slip smearing, particularly at depth where the model is poorly constrained by the data, in order to improve the von Karman probability. To eliminate this bias I modify my Bayesian inversion scheme to solve for the size of the fault plane during the inversion, along with slip, rake and a hyperparameter controlling slip variance. This makes the inversion trans-dimensional, and aims to reduce the bias caused by an incorrect model. I apply it to the Mw 6.2 Central Tottori earthquake, Japan, using InSAR and GNSS (Global Navigation Satellite System) data. My model shows that the earthquake ruptured most of the seismogenic zone, in contrast to seismological studies. My results in this thesis further confirm that fault surface roughness shows fractal properties, and that fault structure may play an important role in the exact relationship between fault topography and the lengthscale of observation. Further investigation of exhumed fault surfaces can help inform earthquake models, including earthquake slip inversions, particularly if an earthquake were to occur on a fault upon which surface roughness measurements had already been taken. By incorporating observed fractal properties into earthquake slip inversions I aim to introduce less bias than other, less physical regularisations. With the European Space Agency's new satellites Sentinel-1a/b providing regular observations of the Earth's deforming regions, we are in a position to model earthquake slip better than ever before. I hope that by incorporating more realistic observations and using Bayesian methods to fully understand uncertainties, we can produce better, more realistic models. These models help our understanding of earthquakes, and, most importantly, earthquake hazard.
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Boutareaud, Sébastien. "Slip-weakening mechanisms at high slip-velocities : insights from analogue and numerical modellings." Besançon, 2007. http://www.theses.fr/2007BESA2030.
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Cette thèse vise à étudier les propriétés thermo-poro-mécaniques de roches de faille, à partir de l’analyse structurale et microstructurale d’une faille aujourd’hui à l’affleurement et à partir d’expériences menées en laboratoire, en vue de déterminer les processus qui contrôlent l'efficacité de deux mécanismes responsables de d’affaiblissement cosismiques : la pressurisation thermique et le mécanisme d’affaiblissement par drainage. L'étude de terrain a été conduite sur deux affleurements appartenant à une faille décrochante potentiellement active appartenant au système de failles du Chugoku occidental (Japon) : la faille d’Usukidani. Le travail expérimental a quant à lui été mené dans le laboratoire de déformation des roches de l'Université de Kyoto. Les résultats majeurs de ce travail sont exposés ci- dessousThis thesis aims at studying the thermo-poro-mechanical properties of fault rock materials by means of field analysis of an exhumed fault and laboratory experiments, in order to determine the processes responsible of the efficiency of two thermally-activated slip-weakening mechanisms: the thermal pressurization and the moisture-drained weakening mechanism. The field study was conducted on well-exposed outcrops of a potentially active strike-slip fault that belongs to the Western Chugoku fault system (Japan): the Usukidani fault. The experimental work was conducted in the rock deformation laboratory at Kyoto University. The primary results of this research are exposed below
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Saxena, Pawan. "Slip casting of silicon nitride." Thesis, McGill University, 1992. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=56974.
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Slip casting is a well established technique for the manufacture of traditional ceramic bodies, such as clays and whitewares. It combines complex shaping with high green densities, resulting in low shrinkage and good densification behaviour.This method, however, has received little attention in the field of engineering ceramics especially with regard to silicon nitride. Commercial fabrication of silicon nitride, a major contender for high temperature applications due to its excellent thermomechanical properties, has been confined to hot pressing. This is an expensive process and has geometrical limitations.
Slip casting, followed by sintering, has been identified as a potentially economical alternative fabrication method, however a number of parameters have to be optimized before a good slip cast silicon nitride body can be made. The aim of the present work is to control parameters such as pH, viscosity and deflocculation in order to form dense, homogeneous, slip cast silicon nitride bodies.
A detailed investigation of the rheological properties of Si$ sb3$N$ sb4$ and careful control of processing parameters, made it possible to produce slip cast Si$ sb3$N$ sb4$ bodies having up to 97% TD on sintering. Mechanical strength values obtained by slip casting were compared with those obtained by die-pressing. Strength values of the slip cast material was limited by iron inclusions entrained in processing.
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Kienhöfer, Frank Werner. "Heavy vehicle wheel slip control." Thesis, University of Cambridge, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.609594.
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Adamson, Alan, and Albert Berdugo. "Helicopter Slip Ring Replacement System." International Foundation for Telemetering, 2010. http://hdl.handle.net/10150/604271.
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ITC/USA 2010 Conference Proceedings / The Forty-Sixth Annual International Telemetering Conference and Technical Exhibition / October 25-28, 2010 / Town and Country Resort & Convention Center, San Diego, CaliforniaMost helicopter programs require the acquisition of parameters from the rotating systems. Historically, these systems made use of electromechanical slip rings for the transfer of power, control, and data from within the helicopter's cabin to the rotating hardware. Slip rings are primarily used in dedicated instrumentation vehicles and are not commonly used in production platforms that may require instrumentation of the rotating systems for in-service load and fatigue monitoring. Additionally, the use of slip rings requires time and money to integrate the hardware and equipment into the aircraft in order to perform rotor data acquisition. The time needed to perform modifications to transmissions and drive trains plays a big factor in the increased costs of aircraft development. Less intrusive installations would minimize the need for mechanical changes and would improve the time needed to install the instrumentation. This paper describes a wireless system approach to perform the test without the slip ring, and provides performance data that validates this new method of instrumenting unobtrusively to save time and money without sacrificing data integrity.
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Sperry, Ryan Aaron. "Characterization of Slip Activity in the Presence of Slip Bands Using Surface-Based Microscopy Techniques." BYU ScholarsArchive, 2020. https://scholarsarchive.byu.edu/etd/8680.
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Further understanding of mesoscale slip mechanics is crucial to future development of polycrystalline metals with improved performance. The research contained within this thesis aims to characterize localized mesoscale slip on slip bands further through two studies. First, a comprehensive comparison of slip system identification techniques was carried out to further validate each method as well as compare advantages and disadvantages of each. Second, slip bands in the presence of grain boundaries were studied to better characterize the dislocation content and behavior. In the first study, the use of SEM-DIC, AFM, ECCI, and HR-EBSD to characterize slip-system activity was assessed on the same material volume of Ti-7Al. This study presents a robust comparison of the various methods for the first time, including an assessment of their advantages and disadvantages, and how they can be used effectively in a complementary manner. The analysis of the different approaches was carried out in a blind manner independently at three different universities. A Ti-7Al specimen was deformed in uniaxial tension to approximately 3% axial strain, and the active slip systems were independently identified using (i) trace analysis; (ii) in-SEM digital image correlation, (iii) observations of residual dislocations from ECCI, and (iv) long-range rotation gradients through HR-EBSD, with consistent trace identification in all cases. Displacement data from AFM was used to augment the SEM-DIC displacement data by providing complementary out of plane displacement information. Furthermore, short-range dislocation gradients (measured by DIC) provided insight into the residual geometrically necessary dislocation (GND) content, and was consistent with the GND content extracted from EBSD data and ECCI images, confirming the presence of residual GNDs on the dominant slip systems resulting in visible slip bands. These approaches can be used in tandem to provide multi-modal information on slip band identification, strain and orientation gradients, out-of-plane displacements, and the presence of GNDs and SSDs, all of which can be used to inform and validate the development of dislocation-based crystal plasticity and strain gradient models. In the second study, shear strain profiles along slip bands in a modified Rolls-Royce nickel superalloy (RR1000) were analyzed for a tensile sample deformed by 2%. The strain increased with distance away from a grain boundary (GB), with maximum shear strain towards the center of the grain, indicating that dislocation nucleation generally occurred in the grain interior. The strain gradients in the neighborhood of the GBs were quantified and generally correlated with rotation about the active slip system line direction. This leads to an ability to determine the active slip system in these regions. The dislocation spacing and pileup stresses were inferred. The dislocation spacing closely follows an Eshelby analytical solution for a single ended pileup of dislocations under an applied stress. The distribution of pileup stress values for GBs of a given misorientation angle follows a log-normal distribution, with no correlation between the pileup stress and the GB misorientation angle. Furthermore, there is no observed correlation between various transmissivity factors and slip band pileup stress. Hence it appears that the obstacle strength of any of the observed GBs is adequate to facilitate the dislocation pileups present in the slip bands. However, slip band transmission does correlate with transmissivity factors, with the current study focusing on the Luster and Morris m'-factor. Observation of strain profiles of transmitted bands indicate dislocation nucleation locations.
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Haynes, Courtney Ann. "Evaluation of Gait and Slip Characteristics for Adults with Mental Retardation." Thesis, Virginia Tech, 2008. http://hdl.handle.net/10919/35952.
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Adults with mental retardation (MR) experience a greater number of falls than their non-disabled peers. To date, efforts to understand the causes for these falls have primarily involved qualitative studies that use largely subjective measures to quantify stability. Performing a more objective biomechanical gait analysis may better explain the reasons for these fall accidents and provide repeatable measures that can be used for comparison to determine the effectiveness of interventions intended to reduce slip-related falls.
A gait analysis was conducted to quantify normal walking and slip response characteristics for adults with MR as well as a group of non-disabled age- and gender-matched peers. Kinetic and kinematic data were collected and a number of variables relating to gait pattern, slip propensity, and slip severity were calculated to compare the differences between groups. Results showed that adults with MR exhibit slower walking speeds, shorter step lengths, and greater knee flexion at heel contact suggesting that their gait patterns share more similarities with the elderly than with healthy adults of an equivalent age. Unexpectedly, the MR group demonstrated a lower required coefficient of friction (RCOF) and slower heel contact velocity which, alone, would suggest a reduced slip propensity as compared with the healthy group. A greater peak sliding heel velocity and greater slip distance measures, however, indicate greater slip severity for the MR group. The findings of this study suggest that falls in this population may be attributed to delayed response to slip perturbation as measured by slip distances.Master of Science
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Sutherland, Duncan. "Numerical study of vortex generation in bounded flows with no-slip and partial slip boundary conditions." Thesis, The University of Sydney, 2014. http://hdl.handle.net/2123/11778.
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The main contributions of this thesis are an investigation of the effect of slip on dipole-wall collisions and a study of topological changes in two-dimensional bounded flows. The Navier-Stokes equations in the streamfunction-vorticity formulation are solved in both a channel domain, periodic in the streamwise direction and also in a disc domain, with either no-slip or Navier boundary conditions. Navier boundary conditions permit some fluid slip along the wall. The normal velocity component at the wall is always zero, but the tangential component of velocity is proportional to the rate of strain at the boundary, with the constant of proportionality identified as the slip length. Recently, Romain Nguyen van yen, Marie Farge, and Kai Schneider, ``Energy dissipating structures produced by walls in two-dimensional flows at vanishing viscosity'', Physical Review Letters, 106:184502, 2011 investigated the problem of a dipole incident on a rigid boundary using a volume penalisation method. The volume penalisation method approximates a no-slip boundary condition and intrinsically introduces some slip at the boundary, which vanishes as the Reynolds number increases. Their results indicate that energy dissipating structures persist in the vanishing viscosity limit. Here a similar problem was investigated using Fourier collocation techniques in the streamwise direction, and a compact finite difference method in the direction normal to the wall. The boundary conditions were enforced using a linear superposition technique called the influence matrix method, modified to treat Navier boundary conditions. For the no-slip boundary condition no evidence of energy dissipating structures was found in the limit as the viscosity approaches zero, and this result also holds for any fixed slip length. However when the slip length was taken to vary inversely with Reynolds number, the results of Nguyen van yen et al were recovered. To investigate the production of enstrophy at the wall it is useful to track the minima, maxima, and saddle points of the vorticity and streamfunction. As coherent structures of vorticity approach near the wall, vorticity is generated at the wall to satisfy the no-slip or Navier boundary conditions and injected into the domain. The flow throughout the domain may be classified into regions dominated by coherent vortices, and regions dominated by filamentary stretching by a condition called the Okubu-Weiss criterion. The Okubu-Weiss criterion can be derived by considering the linear stability of the stagnation points of the flow, and it can be considered as a measure of curvature of the streamfunction. The Gaussian curvature of both the streamfunction and vorticity can be used to directly classify the flow into hyperbolic and elliptical regions. The curvature of the streamfunction is essentially a modification of the Okubu-Weiss criterion and can be interpreted as a balance between vorticity and strain, but the curvature of the vorticity does not appear to have a simple physical interpretation. The Gauss-Bonnet theorem shows that the total Gaussian curvature of both vorticity and streamfunction vanishes for a doubly-periodic domain and for the channel domain. For a disc domain it is possible to derive similar conservation laws. In the channel domain and a disc domain, the total curvature of the streamfunction vanishes, but for the vorticity there is an additional contribution from the curvature of the boundary. The generation and merger of critical points in bounded flows was monitored in an observational study. In an unbounded domain, the well-known forward energy cascade forces energy to large spatial scales. Large numbers of small scale vortices will therefore merge into domain-filling structures. In bounded domains, the wall acts as a source of enstrophy which constantly injects small scale vortices that disturb the formation of organised, domain-filling circulation cells. Fayeza Al Sulti and Koji Ohkitani, ``Vortex merger and topological changes in two-dimensional turbulence'', Physical Review E, 86.1 016309, 2012 studied vortex merger in unbounded domains by counting the number of elliptic and hyperbolic critical points of vorticity and streamfunction. To identify and classify the critical points Al Sulti and Ohkitani used the zeros of gradient of the field and the eigenvalues of the Hessian matrix at those points. In this thesis a new algorithm is developed, based on estimating the the Poincaré-Hopf index near potential critical points. This algorithm avoids the difficulties of identifying the zeros of gradient of the field, instead only local minima are required. Results showing the motion of critical points in time and the variation in the number of critical points over the simulation for a channel geometry are presented. In addition to the overall theme of the effect of the boundary conditions on the interior flow, the influence matrix method has been improved into a powerful and efficient numerical method for studying viscous fluid flow. The extension to generalised boundary conditions also allows a careful comparison of the volume penalisation method, with its intrinsic approximation to no-slip boundary conditions, against methods that enforce the no-slip boundary conditions exactly.
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Nibur, Kevin Andrew. "Nanoindentation slip steps and hydrogen embritlement." Online access for everyone, 2005. http://www.dissertations.wsu.edu/Dissertations/Summer2005/k%5Fnibur%5F071305.pdf.
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Frylmark, Daniel, and Stefan Johnsson. "Automatic Slip Control for Railway Vehicles." Thesis, Linköping University, Department of Electrical Engineering, 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-1765.
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In the railway industry, slip control has always been essential due to the low friction between the wheels and the rail. In this master’s thesis we have gathered several slip control methods and evaluated them. These evaluations were performed in Matlab-Simulink on a slip process model of a railway vehicle. The objective with these evaluations were to show advantages and disadvantages with the different slip control methods.
The results clearly show the advantage of using a slip optimizing control method, i.e. a method that finds the optimal slip and thereby maximizes the use of adhesion. We have developed two control strategies that we have found superior in this matter. These methods have a lot in common. For instance they both use an adhesion observer and non-linear gain, which enables fast optimization. The difference lies in how this non-linear gain is formed. One strategy uses an adaptive algorithm to estimate it and the other uses fuzzy logic.
A problem to overcome in order to have well functioning slip controllers is the formation of vehicle velocity. This is a consequence of the fact that most slip controllers use the velocity as a control signal.
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Williams, Cheri Lynne. "Egyptian Red Slip Pottery at Aila." NCSU, 2009. http://www.lib.ncsu.edu/theses/available/etd-08172009-104842/.
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The Roman Aqaba Project, an archaeological investigation of a Roman port on the Red Sea in southern Jordan, recovered over 500 sherds of Egyptian Red Slip Ware (ERS). This included both ERS A (presumably from the Aswan region of Upper Egypt) and ERS B (from various production centers along the Nile valley). ERS was the second most common imported fine ware found at Aila from the Late Roman and Byzantine periods (3rd through early 7th centuries A.D.), trailing far behind African Red Slip Ware (from Tunisia) but easily exceeding imports of Cypriote Red Slip and Phocaean Red Slip (from the Aegean). The most striking fact about the ERS at Aila is its chronological distribution. In most parts of Palestine and Jordan ERS appears in quantity only in the late 6th and 7th centuries. But at Aila both ERS A and ERS B wares begin appearing in securely attested 3rd century contexts and are most common in the 4th century, long before their appearance in the remainder of the Levant, generally in late 6th and 7th centuries.
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Ranvik, Arne. "Slip Prediction Based on Manipulator Motion." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for teknisk kybernetikk, 2014. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-26705.
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Predicting slip during robotic manipulation is of interest for a variety of appli-cations. Especially applications where weak grasps are applied. In this thesis, amodel for predicting slip for a two fingered grasping scenario is considered. Otherthan model parameters, the only measurements or sensor information assumed isof the manipulator joints. Soft objects that deform substantially under appliedforces are especially interesting in terms of frictional behaviour. A soft ball wasused as a test object and parameters for friction and deformation was experimen-tally determined. By grasping and moving the ball with an industrial manipulator,slip and object loss was induced in order to compare these observations againstmodel predictions.It was found that the models prediction of slip was reasonable when compared tothe observations. However, the model could not be fully tested and validated be-cause the simple geometry of the test object did not excite any frictional behaviourfrom the soft characteristics.
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Манько, Наталія Миколаївна, Наталья Николаевна Манько, and Nataliia Mykolaivna Manko. "Stick-slip mode of boundary friction." Thesis, Сумський державний університет, 2013. http://essuir.sumdu.edu.ua/handle/123456789/33545.
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The study of the boundary friction processes that develop in nanosized tribosystems has drawn active interest of many researchers. One of the perspective directions is the investigation of the friction of atomically smooth solid surfaces in the presence of an ultrathin film of a homogeneous lubricant between them. The interest is partially due to the applied significance of these systems, as they are used in increasing frequency to design precise devices and instruments.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/33545
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Vega, Sanchez Christopher. "Fluid Slip On Lubricant-Infused Surfaces." Thesis, The University of Sydney, 2022. https://hdl.handle.net/2123/29511.
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Fluid slip on surfaces is a highly desirable property for many applications, as it reduces the frictional drag, thereby reducing the energy associated with fluid transport. Lubricant-infused surfaces (LIS), in which a gas or liquid is entrapped within the surface roughness, have been proposed as a passive method to enhance fluid slip. Gas-infused surfaces (superhydrophobic surfaces) have been the focus of attention for decades as the liquid-gas interface is (almost) shear-free. However, the infused gas in superhydrophobic surfaces is unstable under hydrostatic pressure and flow, which cause the fluid slip to vanish.
Liquid-infused surfaces have been proposed as an alternative to mitigate some of these issues, as the incompressible liquid lubricant is stable under high pressures. However, the use of a liquid lubricant has other implications: first, the presence of the liquid lubricant is expected to be only beneficial for slip if its viscosity is lower than that of the flowing fluid. Second, the liquid lubricant can be depleted under shear imposed by the external flow, leading to the disappearance of the slippery properties. Finally, given their recent development, there are only few studies of slip on liquid-infused surfaces.
In this Thesis, three outstanding aspects of slip on lubricant-infused surfaces were investigated: 1) the impact of (partial) lubricant depletion on the effective slip; 2) the development of experimental methods to accurately quantify slip on structured surfaces, and 3) reconciling experimental measurement of slip on smooth and rough lubricant-infused surfaces with existing theoretical models. The numerical and experimental results indicate that the mechanism responsible for the fluid slip is the spontaneous nucleation of nanobbubles.
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Grigg, John Antony Hugh. "Superconductive Effects in Thin Cluster Films." Thesis, University of Canterbury. Department of Physics and Astronomy, 2012. http://hdl.handle.net/10092/10376.
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In this thesis, the superconductive and superresistive properties of thin percolating films of lead nanoclusters are presented. The samples were created by depositing clusters from an inert gas aggregation cluster source onto substrates held at either room temperature or 10K.
Observations of the characteristic behaviours of the samples were made through R(T ) and V (I) measurements. Several interesting features were observed - smooth and discrete steps in the R(I) curves, hysteresis between increasing and decreasing bias currents, and non-zero resistances at superconducting temperatures. Explanations are proposed in terms of theoretical models of several phenomena - phase slips, phase slip centres and hotspots - which have seen little prior application to percolating systems in literature.
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Breguet, Jean-Marc Breguet Jean-Marc. "Actionneurs "stick and slip" pour micro-manipulateurs /." [S.l.] : [s.n.], 1998. http://library.epfl.ch/theses/?display=detail&nr=1756.
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Schmalzle, Gina Marie. "The Earthquake Cycle of Strike-Slip Faults." Scholarly Repository, 2008. http://scholarlyrepository.miami.edu/oa_dissertations/177.
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An earthquake is a mechanism of stress release along plate boundaries due to relative motion between the Earth's lithospheric blocks. The period in which stresses are accruing across the plate boundary is known as the interseismic portion of the earthquake cycle. This dissertation focuses on interseismic portion of the earthquake cycle to extract characteristics of fault, shear zone and rock properties. Global Positioning System (GPS) data are used to observe the pattern of deformation across two primarily strike-slip fault systems: the Carrizo Segment of the San Andreas Fault (SAF) and the Eastern California Shear Zone (ECSZ). Two sets of GPS data are processed, analyzed and applied to analytic and numerical models describing the interseismic behavior of the earthquake cycle. The Carrizo segment is mature (i.e., had many earthquakes) and has juxtaposed terrains with varying rock properties laterally across the fault system. Lateral variations in rock properties affect the pattern of deformation around strike-slip faults and affect how surrounding rock deforms and if not considered may bias the interpretation of the faulted system. The Carrizo segment separates Franciscan terrain northeast of the fault from Salinian block to the southwest. GPS data are well fit to a model with a 15-25 km weak zone northeast of the Carrizo segment. The long-term slip rate estimated on the SAF is 34-38 mm/yr, with 2-4 mm/yr accommodated on faults to the west. The viscosity for the combined lower crust/upper mantle is estimated at 2-5x10^19 Pa s. This model is consistent with the distribution of rock type and corresponding laboratory data on their material properties, paleoseismic, seismic and magnetotelluric data. The ECSZ is a young (<10 >Myr) system of strike-slip faults including the Owens Valley - Airport Lake, Panamint Valley - Ash Hill - Hunter Mountain and Death Valley - Furnace Creek fault systems. The ECSZ study concentrates on fault evolution by finding the current position of maximum shear across the shear zone and estimating fault rates. Geologic studies suggest that the Death Valley - Furnace Creek fault system on eastern end of the ECSZ was the primary accommodator of slip early in the ECSZ history. This study suggests that the current locus of shear has shifted westward, and resides in the center of the ECSZ under the Panamint Valley - Ash Hill -Hunter Mountain fault system. The model dependent estimated geodetic rate of the Ash Hill - Panamint Valley -Hunter Mountain fault system (4.91-6.11 mm/yr) is faster than geologic estimates (1.6 - 4 mm/yr). The result is interpreted as a simplification of the ECSZ with time, combined with progressive westward migration of deformation. The best estimate for a combined rate across the shear zone is 10 mm/yr (20% of total Pacific-North America motion). The summation of rates obtained by this study is 49 mm/yr, well within estimates obtained by previous studies using independent techniques.
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Lloyd, Jeffrey Townsend. "Implications of limited slip in crystal plasticity." Thesis, Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/34808.
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To better understand consequences of classical assumptions regarding deformation mechanisms at the mesoscale, experimental observations of mesoscale deformation are presented. In light of actual micrographics of deformed polycrystals, the Von Mises criterion which states that 5 independent plastic deformation sources are needed at each material point to satisfy compatibility is studied, and the consequences of violating this assumption are presented through comprehensive parametric studies. From these studies, it can be concluded that not only are 5 independent plastic deformation sources not needed or observed at each point, but if less than 5 sources are allowed to be active a new physical understanding of a mechanism for kinematic hardening emerges. Furthermore, for enhanced subgrain rotation and evolution the Von Mises criterion must be violated. The second focus of this work is looking at studies, experiments, and models of mesoscale deformation in order to better understand controlling deformation length scales, so that they can be fed into a combined top-down, bottom-up, non-uniform crystal plasticity model that captures the variability provided by the mesoscale during deformation. This can in turn be used to more accurately model the heterogeneity provided by the response of each grain. The length scale intuited from insight into mesoscale deformation mechanisms through observation of experiments and analytical models is the free slip line length of each slip system, which informs non-uniform material parameters in a crystal plasticity model that control the yielding, hardening, and subsequent softening of each individual slip system. The usefulness of this non-uniform multiscale crystal plasticity model is then explored with respect to its ability to reproduce experimentally measured responses at different strain levels for different size grains. Furthermore, a "Mantle-Core" type model which combines both the non-uniform material parameter model and the limited slip model is created, in which the majority of plastic deformation is accommodated near the grain boundary under multi-slip, and uniform plastic deformation occurs in the bulk dominated by double or triple slip. These models are compared for similar levels of hardening, and the pole figures that result from their deformation are compared to experimental pole figures. While there are other models that can capture the heterogeneity introduced by mesoscale deformation at the grain scale, this combined top-down, bottom-up multiscale crystal plasticity model is by far one of the most computationally efficient as the heterogeneity of the mesoscale is does not emerge by introducing higher order terms, but rather by incorporating the heterogeneity into a simple crystal plasticity formulation. Therefore, as computational power increases, this approach will be among the first that will be able to perform accurate polycrystal level modeling while retaining the heterogeneity introduced by non-local mesoscale deformation mechanisms at the sub-grain scale.
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Lai, Derek. "Crack shear-slip in reinforced concrete elements." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp05/MQ62951.pdf.
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Yin, Lan 1969. "GPS based positioning with cycle slip detection." Thesis, McGill University, 2003. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=79206.
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This thesis is concerned with development and implementation of an efficient and numerically reliable positioning algorithm based on the combination of code pseudorange (C/A) and carrier phase (L1) measurements with cycle slip detection.In GPS a typical technique for kinematic position estimation is relative positioning where two receivers are used, one receiver is stationary and its exact position is known, the other is roving and its position is to be estimated. We describe the physical situation and give the mathematical model based on the difference of the measurements at the stationary and roving receivers. The model we consider combines both code pseudorange and carrier phase measurements. We then present: a recursive least squares approach for position estimation. We take full account of the structure of the problem to make our algorithm efficient, and use orthogonal transformations to ensure numerical reliability of the algorithm.
At each epoch, possible cycle slips must be detected, otherwise it may significant deteriorate the positioning accuracy. A cycle slip detection method based on the higher-order difference technique, one of typical techniques for cycle slip detection, is developed and incorporated into the preprocess of our positioning algorithm.
Finally, real data testing for our positioning algorithm and cycle slip detection algorithm are performed. The results suggest our algorithms are very effective.
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Smillo, Fabricio. "Wall slip and spurt of molten polymer." Thesis, McGill University, 2004. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=81570.
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A Monsanto Automatic Capillary Rheometer and a sliding plate rheometer were used to study the spurt phenomenon and to discover whether it is the result of a system instability or a material property. The capillary rheometer has been the only instrument able to operate at spurt stresses up to present time, because capillary rheometers operate at shear stresses that are out of the range of rotational shear rheometers. However, a sliding plate rheometer can generate shear stresses in the spurt range. A comparative study using two linear polybutadiene samples at 50°C was carried out using these two rheometers. Special attention was paid to the evaluation of the actual pressure drop in the capillary in order to determine the true shear stress at the wall. It was found that spurt occurs only in the capillary rheometer. In other words, the flow curve generated by the sliding plate rheometer is continuous in the shear stress range where spurt is observed in the capillary rheometer. Slip velocities were determined using data from the two rheometers, and the slip velocities for the post-slip capillary flow all fall on the smooth curve based on sliding plate data, provided that the pressure drop in the capillary, and not the overall driving pressure, is used to calculate the wall shear stress.
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Smith, Jonathan Hurndall. "Stick-slip vibration and is constitutive laws." Thesis, University of Cambridge, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.304168.
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Qiu, Hui. "Slip and edge effect in complete contacts." Thesis, University of Oxford, 2008. http://ora.ox.ac.uk/objects/uuid:d4ea2006-5a87-46c6-be0d-2a4c55b272da.
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The general problem of an anticrack, present in a simple domain and subject to general remote loading is solved using distributed line forces, acting as strain nuclei, along the line of the anticrack. Subsequently, both dislocations and point forces are used as strain nuclei to achieve mixed boundary value conditions. The influence function for a pair of forces applied to the faces of a semi-infinite notch is found and finally this is used to find the true closure length and interfacial contact pressure. When a sharp-edged indenter is pressed into a half plane material in the half-plane is displaced and 'laps around' the edges of the punch, possibly making contact with the side faces. This phenomenon is quantified within (coupled) half-plane theory, and applied first to an idealised indenter having the cross section of a trapezium, and then to a semi-infinite indenter. The latter allows an asymptotic form to be found which, through a generalised stress intensity factor may be collocated into the edge of any notionally sharp-edged indentation problem. The effect of surface strains on the local slip angle, when an infinite cylinder is slid skew-wise across an elastically similar half-plane is found. It is shown that local frictional orthogonality is not completely consistent with global orthogonality. The problems of a square-ended and an almost square-ended rigid punch sliding with both plane and anti-plane velocity components are studied. It is shown that, for a truly complete contact, if the contacting body is incompressible, convection effects are absent. Introducing either: (a) local rounding or (b) finite compressibility of the contacting body into the problem introduces convection, giving rise to an inconsistency between the global and local requirement of the orthogonal friction law. The state of stress in a three-quarter-plane undergoing antiplane shear deformation is studied, due to the presence of a screw dislocation along one of the projection lines extending from the free surfaces. A simple, accurate formula for the state of stress along the line is found, providing a useful kernel for the solution of crack and contact edge slip problems. The state of stress induced in an axi-symmetric solid formed from a half-space and a bonded semi-infinite rod, by a family of ring dislocations of arbitrary Burgers vector is found. Particular care is given to the interaction between the Cauchy singularity near the dislocation core and the geometric singularity at the rod/half-space junction. Torsional contact between a semi-infinite elastic rod with square ends and an elastically similar half-space was then solved using the ring dislocations as influence functions. This provides an excellent illustration of the imposition of orthogonality condition for a complete contact.
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Sainoki, Atsushi. "Dynamic modelling of mining-induced fault-slip." Thesis, McGill University, 2014. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=123291.
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In deep hard rock mines where high stress conditions take place, rockbursts are serious problems because rockbursts could result in severe damage to mine openings. It is widely recognized that mining activities could reactivate faults in underground mines. The reactivation of faults could then cause fault-slip. More importantly, fault-slip gives rise to seismic waves, which inflict severe damage to mine openings. Because the generation and propagation of seismic waves are dynamic phenomena, fault-slip needs to be also dealt with as a dynamic phenomenon. Both of the static and dynamic behaviour of faults should be examined, considering the effects of mining activities on the faults, in order to estimate the damage induced by the seismic waves First, a literature review is conducted. The review has revealed that although a number of dynamic and static friction laws have been proposed, the friction laws have been rarely employed for the simulation of fault-slip in underground mines. The review has also revealed that most of the simulations have been conducted in static conditions. In this thesis, dynamic modelling of mining-induced fault-slip is presented using a mine-wide model encompassing a fault. Furthermore, a case study of Garson Mine, Sudbury, Canada is carried out. A parametrical study with a mine-wide 3D model has led to the following conclusions: (a) mining depth, friction angle of the fault, and fault locations exert a large influence on the maximum relative shear displacements on the fault, while the dilation angle and stiffness of the fault do not, (b) maximum slip rates appear to increase with the maximum slip. Results obtained from the numerical analysis employing Barton's shear strength model have shown that fault surface roughness strongly affects the intensity of seismic waves and seismically radiated energy. The results imply that fault-slip occurring on faults with rough surfaces could become more violent. The effect of stope production blasts on a nearby fault is also examined. The results obtained from the analysis have indicated that performing stope production blasts in timed sequence could induce a larger seismic event on the fault than triggering the blasts simultaneously. Dynamic analysis considering the collision and unloading of fault surface asperities is also conducted. It is found that the release of normal stress due to fault unloading has a large influence on the intensity of seismic waves. The effect of slip-weakening distance on seismic source parameters of fault-slip is also investigated. The study has indicated that slip rates and seismically radiated energy are significantly affected by the slip-weakening distance, while seismic moment appears not to be susceptible to the slip-weakening distance in a case of local fault-slip.Back analysis of fault-slip to estimate the physical and mechanical properties of shear/fracture zones is carried out for Garson Mine. The back analysis is conducted with respect to moment magnitude and peak particle velocities recorded by seismic monitoring systems. Fault surface roughness and a dynamic friction angle have been calibrated. Afterwards, the calibrated values are validated with peak ground acceleration. Through the study, a methodology to calibrate the physical and mechanical properties of faults by means of ground motion due to seismic waves arising from fault-slip as well as seismic source parameters of the fault-slip has been developed.Dans les mines profondes ou des contraintes élevées se produisent, les coups de terrain sont un problème car les ils peuvent endommager les ouvertures minières. Il est largement reconnu que les activités minières peuvent réactiver des failles dans les mines sous-terraines. La réactivation de ces failles peut entrainer un glissement de faille. Surtout, le glissement de faille fait naitre des ondes sismiques qui infligent des dégâts sérieux quand elles frappent la surface des ouvertures minières. La génération et la propagation des ondes sismiques sont des phénomènes dynamiques. Il s'ensuit donc que le glissement de faille doit être traité comme un phénomène dynamique Le comportement dynamique ainsi que le comportement statique des failles doit être examiné en considérant les effets des activités minières pour estimer les dégâts causés par les ondes sismiques.Premièrement, un examen de la documentation est effectué. L'examen a révélé que même si un nombre de lois statiques et dynamiques de frottement ont été proposés, ces lois de frottement ont été peu employés pour simuler les glissements de faille que se déroulent dans les mines sous-terraines. La revue a aussi révélé que la majorité des simulations ont été conduites en conditions statiques. Dans cette thèse, la modélisation dynamique d'un glissement de faille induit par des activités minières est présentée. Le modèle englobe l'entièreté d'une mine. En plus, une étude de cas pour la mine Garson à Sudbury, au Canada, est effectuée.Une étude paramétrique avec un modèle de mine en trois dimensions mène aux conclusions suivantes: (a) la profondeur d'exploitation minière, l'angle de friction de la faille, et la position de la faille ont une grande influence sur les déplacement relatifs en cisaillement d'une faille, tandis que l'angle de dilation de la faille et la dureté ont peu d'effet, (b) le taux de glissement maximal augmente en fonction du glissement absolu. Les résultats obtenus du modèle numérique dans lequel le modèle de résistance au cisaillement de Barton est implémenté ont démontré que la rugosité de la surface de la faille affecte grandement l'intensité des ondes sismiques qui émanent du glissement de faille et l'énergie sismique propagée. Les résultats impliquent qu'un glissement de faille survenant à une faille rugueuse est plus violent. L'effet produit par un sautage de production sur une faille proche est aussi examiné en considérant plusieurs séquences de sautage. Les résultats de l'analyse indiquent qu'un sautage de production exécuté selon une séquence temporelle peut induire un plus grand événement sismique qu'un sautage simultané. Une analyse dynamique tenant compte la collision et le déchargement d'une faille est aussi conduite. Il est démontré que le relâchement de la contrainte normale à la faille a une grande influence sur l'intensité des ondes sismiques. L'effet de la distance d'affaiblissement de faille due glissement sur les paramètres sismiques est aussi examiné L'étude indique que le taux de glissement et l'énergie sismique émanée sont significativement affectés par la distance d'affaiblissement de faille, tandis que le moment sismique n'est pas susceptible à la distance d'affaiblissement dans le cas ou le glissement de faille se déroule seulement dans une zone limitée. Pour estimer l'effet des propriétés physiques et mécaniques de la zone de cisaillement, une analyse régressive est exécutée pour la mine Garson. L'analyse est conduite selon la magnitude du moment et la vitesse de crête des particules. La rugosité de la surface de la faille et l'angle de friction dynamique sont étalonnés. Ensuite, les paramètres étalonnés sont validés par rapport à l'accélération maximale du terrain. À travers l'étude, une méthodologie pour étalonner les propriétés physiques et mécaniques de la faille selon l'étude du mouvement du terrain due aux ondes sismiques émanant d'un glissement de faille est développé.
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Webber, Mark. "Instability of fluid flows, including boundary slip." Thesis, Durham University, 2007. http://etheses.dur.ac.uk/2308/.
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We investigate the onset of instability in a variety of fluid models, and present results and details of their computation in each case. The fluid models we consider are: convection in the setting of the Navier-Stokes equations with boundary slip; Poiseuille-type solutions of the Navier-Stokes equations, again with boundary slip; Poiseuillfe-type solutions of the Green-Naghdi and dipolar fluid equations. In Chapter two we examine the onset of thermal convection in a thin fluid layer, with slip boundary conditions at the top and bottom surfaces of the layer. We show that non-zero boundary conditions do not affect the classical steady state solution, and the principle of exchange of stabilities still applies. It is seen that boundary slip reduces the critical Rayleigh number at which convection begins, below that found in the setting of no-slip boundary conditions. The next two chapters concern the transition to turbulence of pressure driven flow in a microchannel, at the boundaries of which the fluid obeys slip boundary conditions. In Chapter three we perform linear and nonlinear stability analyses for this flow, and show that we do not have exchange of stabilities for such flows. In Chapter four we perform a linear stability analysis for channel flow in the case when the fluid viscosity is a function of temperature. We show that for pressure driven flow in the plane, boundary slip stabilizes the flow. In Chapter five we develop a model of thread-annular flow, in which we believe boundary slip to be an important part. As well as our development of the model, we present previously unpublished results on the linear stability of thread-annular flow to non-axisymmetric disturbances. Some surprising behaviour is observed in the neutral curves, including behaviour missed by the computations of previous authors. Finally, we use Chapter six to discuss two alternative fluid models: the Green- Naghdi equations and the dipolar equations. We find Poiseuille flow type solutions in both of these settings, and perform linear stability analyses. These fluid models are systems of fourth order differential equations, and we show that the fourth order derivative terms dominate the stability of the flow.
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Nash, C. R. "Circuit elements for quantum phase-slip devices." Thesis, University College London (University of London), 2017. http://discovery.ucl.ac.uk/1558026/.
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If proved to exist, the phenomenon of quantum phase slips (QPS) allows us to provide a new standard for current. In order to investigate this effect a QPS circuit needs to be constructed with a superconducting nanowire connected in series with an inductor and two thin film resistors. It was found that it was possible to control the low temperature resistance of chromium oxide films by increasing the oxygen pressure at the time of deposition, meaning chromium oxide films could be fabricated for a large resistance range of thin film resistors, from values in the hundreds of ohms to megaohms. These films were found to be amorphous when measured with XRD and displayed extremely low magnetoresistance (with a peak magnetic moment of 5x10 3 μB per atom, compared to 2 μB per atom in bulk ferro- magnetic Cr2O3). The contact resistance of joining these chromium oxide resistors to gold or niobium-silicon was measured using a transmission-line model and this revealed that a gold interlayer provided a much lower contact resistance than direct contact of the circuit components (a contact resistivity of 0.15 m Ohm cm2 for chromium oxide to gold compared to 65 m Ohm cm2 for chromium oxide to niobium silicon). Several methods were used to restrict nanowire dimensions. It was found that combining a HSQ fabrication method with a neon mill resulted in the creation of wires below the coherence length of niobium nitride (30 nm), which made these wires suitable for QPS measurements.
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Staroselsky, Alexander V. 1962. "Crystal plasticity due to slip and twinning." Thesis, Massachusetts Institute of Technology, 1998. http://hdl.handle.net/1721.1/17450.
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Wang, Mengchen. "Rheological Behavior of Wall-Slip Dominant Solutions." University of Akron / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=akron1427994338.
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Bamford, Thomas Anthony. "Slip propagation across high angle grain boundaries /." The Ohio State University, 1986. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487265555439854.
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Wise, Cynthia Marie. "TEM study of slip propagation in metals /." The Ohio State University, 1988. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487596307356099.
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Song, Seok-Goo. "Source characteristics of large strike-slip earthquakes /." May be available electronically:, 2007. http://proquest.umi.com/login?COPT=REJTPTU1MTUmSU5UPTAmVkVSPTI=&clientId=12498.
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Hunter, Diane T. "Evaluation of slip resistance for Company Y." Online version, 2008. http://www.uwstout.edu/lib/thesis/2008/2008hunterd.pdf.
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Hartman, John Sommer H. J. "Evaluation of a foot-mounted slip sensor." [University Park, Pa.] : Pennsylvania State University, 2009. http://honors.libraries.psu.edu/theses/approved/WorldWideIndex/EHT-16/index.html.
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Webb, Joseph Ray. "Slip Lined Culvert Retrofit and Fish Passage." BYU ScholarsArchive, 2009. https://scholarsarchive.byu.edu/etd/2321.
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Culverts throughout the country are approaching or are past their original design lives. These ‘baby boomer’ culverts will need to be repaired, rehabilitated, or replaced. Because entire culvert replacement is so expensive and intrusive, alternate measures to extend the culvert project life are growing increasingly popular. One such method is slip lining, where a ‘sleeve’ is installed within an existing culvert barrel and stabilized. Plastic pipe sleeves are very popular for slip lining primarily because the plastic material's lower Manning's roughness values allow for the culvert capacity to be maintained despite a reduction in culvert size. Unfortunately, the reduced friction within the barrel can create a barrier to fish passage due to increased water velocities. The increased velocities also cause greater outlet scour which can result in further obstacles to fish passage. These new fish barriers can greatly affect aquatic ecosystems by limiting the access that fish have to smaller tributaries used for spawning and rearing—access that is critical to the life cycles of many fish. It is suggested that mitigation of the increased velocities should go hand-in-hand with slip lined culvert design projects where fish passage (present or future) is to be considered. Can the demand for hydraulic capacity as well as the demand for fish passage be satisfied? Careful design and installation, coupled with post-project monitoring can result in slip lined culvert retrofits which successfully pass fish. Investigation of federal and state laws and various agency guidelines has informed the creation of a list of culvert conditions which should prompt consideration of slip lined culvert retrofit among other design alternatives. Additionally, a literature review and survey of all U.S. state Departments of Transportation as well as state Fish and Wildlife Departments has shown that there has been very limited experience in providing for fish passage through slip lined culverts. Literature and practice has pointed to the use of baffles and tailwater control weirs for velocity mitigation. Site visits have been made to the few states with this experience to assess developing technologies and record successful and unsuccessful installations. Additional hydraulic analysis using current software suggests general trends in the effects slip lined culvert retrofits on flow type, headwater, velocity as well as the effects of tailwater control weirs. Issues of sustainability, constructability and maintenance, as well as monitoring are addressed.
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Webb, Robert D. "A literature review of slip ring performance and an evaluation of four lubricants in a slip ring wear application." Master's thesis, This resource online, 1994. http://scholar.lib.vt.edu/theses/available/etd-02022010-020203/.
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Xu, Junke 1976. "Nonlinear viscoelasticity and wall slip of molten polymers." Thesis, McGill University, 2005. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=82644.
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Two nearly monodisperse polybutadienes (PBd) having different molecular weights were used to study nonlinear viscoelastic behavior using a sliding plate rheometer incorporating shear and normal stress transducers.Comparison of data for the shear stress growth function at the start-up of steady simple shear with predictions of the Wagner model was used to estimate the time-dependency of wall slip. Both the time-dependent slip velocity and the steady-state values were found to depend on molecular weight, thus supporting the hypothesis that "slip" actually involves a shear-induced disentanglement between molecules strongly adsorbed at the wall and those in the bulk. The critical shear stress for the onset of slip was about 230kPa for both PBds, suggesting that the critical stress is independent of molecular weight and related to the plateau modulus. Slip behavior on steel and glass substrates was quite similar. Rubber-like high-molecular-weight polybutadiene exhibited well-defined, steady, normal stresses at moderate shear rates, while molten polystyrene exhibited a steady normal stress up to much higher shear rates.
Step strain data were used to determine the time and strain dependency of the nonlinear relaxation modulus. Time-strain factorability was observed, and the damping function was determined. For the moderately entangled PBd2 the experimentally determined damping function agreed with the predictions of the Doi-Edwards constitutive model and thus the Lodge-Meissner relationship. The higher molecular weight PBd3 exhibited strong wall slip.
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Engman, Marcus, and Andreas Szilassy. "Powertrain dynamic torque reduction using clutch slip control." Thesis, KTH, Fordonsdynamik, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-172211.
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The torque dynamic caused by the firing pulse from diesel engines set high robustness demands for gearboxes and final drives in today’s heavy duty trucks. If these dynamic loads could be eliminated or dampened, the driveline can be built lighter because of the lower demands which in turn would save fuel for the driver and material cost for the manufacturer. There exist solutions to this problem that include expensive and complicated hardware; for example the double mass flywheel, but there is one opportunity that is potentially for free to the manufacturer, namely clutch slip control. The hypothesis of this thesis is that the torque oscillations from the engine can be reduced by controlling the clutch slip velocity. It is also evaluated if it is possible to control a slip using existing hardware in a Scania powertrain and if the control performance can be improved by changing one of the powertrain parameters. For the scope of this thesis, the wear rate and temperature of the clutch when slipping is not considered. The first step of the thesis is to construct a MBS model of the powertrain in question. Further on, two control designs, namely fuzzy control and two degrees of freedom control are implemented using model based control design. Both control algorithms are implemented in a heavy duty truck and the performance is evaluated. To find the parameter that constrains the performance, a parameter variation is performed using the developed model to save both time and cost. It is proved that the torque dynamics from the diesel engine can be dampened by forty to eighty percent in amplitude by slipping the clutch and that the implemented control design gives acceptable results for gears seven to twelve using existing hardware. The parameter variation shows that the actuation delay is the main limiting factor, enabling stable control at the first gear if removed completely. The slip control concept shows potential but sets high demands for hardware specification, especially for actuation delays if all gears are to be used with slip control. Using existing hardware, the control is fully implementable for gears seven to twelve with good results.Det dynamiska momentet som tändpulserna ger upphov till i dieselmotorer ställer höga krav på robusthet och hållfasthet hos växellådor och slutväxlar i lastbilar. Om dynamiken kunde elimineras eller dämpas ut vore det möjligt att bygga transmissionen lättare eftersom kraven på robusthet och hållfasthet skulle minska. Detta skulle i slutändan betyda lägre bränsleförbrukning för åkeriet och lägre materialkostnader för lastbilstillverkaren. I dagsläget finns det flera dyra lösningar som bygger på komplicerade mekaniska koncept, däribland dubbelmassesvänghjulet, men det finns en möjlighet som potentiellt är gratis för tillverkaren ur ett materialperspektiv, nämligen kopplingsslirkontroll. Hypotesen i det här examensarbetet är att momentoscillationerna från motorn kan reduceras genom att kontrollera slirhastigheten i kopplingen. Det utvärderas också om det är möjligt att kontrollera slirhastigheten genom att använda komponenterna i en befintlig, produktionssatt Scania drivlina och om det finns en nyckelparameter i hårdvaran som tydligt begränsar regleringens prestanda. Kopplingens temperatur och slitning anses vara utanför ramen för detta examensarbete och behandlas inte i denna rapport. Som första steg i utvecklingen konstrueras en MBS-modell av drivlinan i fråga. Fortsättningsvis implementeras två reglerstrukturer, nämligen fuzzy-reglering och tvåfrihetsgradsreglering genom att använda modellbaserad utveckling. För att utreda prestandan i dagens system implementeras båda reglerstrukturerna i en lastbil där verklig provning utförs. För att hitta den begränsande faktorn utförs en parametervariation i den utvecklade modellen istället för i en lastbil, vilket sparar både tid och minskar kostnaden. I det här examensarbetet har det visats att momentdynamiken från dieselmotorn kan dämpas ut med fyrtio till åttio procent i amplitud genom att slira på kopplingen och att den implementerade reglering ger en acceptabel prestanda för växlarna sju till tolv i existerande hårdvara. Den utförda parametervariationen visar att fördröjningen mellan beräknad styrsignal och faktisk aktuering är mest begränsande och att en eliminering av denna möjliggör stabil reglering på första växeln. Kopplingsslirregleringskonceptet visar stor potential men sätter höga krav på hårdvara; inte minst aktueringsfördröjningen om regleringen ska användas på alla växlar. Med existerande drivlina är dock regleringen fullt implementerbar sju till och med tolv.
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Szilassy, Andreas, and Marcus Engman. "Powertrain dynamic torque reduction using clutch slip control." Thesis, KTH, Maskinkonstruktion (Inst.), 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-157662.
Full textAbstract:
The torque dynamic caused by the firing pulse from diesel engines set high robustness demands for gearboxes and final drives in today’s heavy duty trucks. If these dynamic loads could be eliminated or dampened, the driveline can be built lighter because of the lower demands which in turn would save fuel for the driver and material cost for the manufacturer. There exist solutions to this problem that include expensive and complicated hardware; for example the double mass flywheel, but there is one opportunity that is potentially for free to the manufacturer, namely clutch slip control. The hypothesis of this thesis is that the torque oscillations from the engine can be reduced by controlling the clutch slip velocity. It is also evaluated if it is possible to control a slip using existing hardware in a Scania powertrain and if the control performance can be improved by changing one of the powertrain parameters. For the scope of this thesis, the wear rate and temperature of the clutch when slipping is not considered. The first step of the thesis is to construct a MBS model of the powertrain in question. Further on, two control designs, namely fuzzy control and two degrees of freedom control are implemented using model based control design. Both control algorithms are implemented in a heavy duty truck and the performance is evaluated. To find the parameter that constrains the performance, a parameter variation is performed using the developed model to save both time and cost. It is proved that the torque dynamics from the diesel engine can be dampened by forty to eighty percent in amplitude by slipping the clutch and that the implemented control design gives acceptable results for gears seven to twelve using existing hardware. The parameter variation shows that the actuation delay is the main limiting factor, enabling stable control at the first gear if removed completely. The slip control concept shows potential but sets high demands for hardware specification, especially for actuation delays if all gears are to be used with slip control. Using existing hardware, the control is fully implementable for gears seven to twelve with good results.Det dynamiska momentet som tändpulserna ger upphov till i dieselmotorer ställer höga krav på robusthet och hållfasthet hos växellådor och slutväxlar i lastbilar. Om dynamiken kunde elimineras eller dämpas ut vore det möjligt att bygga transmissionen lättare eftersom kraven på robusthet och hållfasthet skulle minska. Detta skulle i slutändan betyda lägre bränsleförbrukning för åkeriet och lägre materialkostnader för lastbilstillverkaren. I dagsläget finns det flera dyra lösningar som bygger på komplicerade mekaniska koncept, däribland dubbelmassesvänghjulet, men det finns en möjlighet som potentiellt är gratis för tillverkaren ur ett materialperspektiv, nämligen kopplingsslirkontroll. Hypotesen i det här examensarbetet är att momentoscillationerna från motorn kan reduceras genom att kontrollera slirhastigheten i kopplingen. Det utvärderas också om det är möjligt att kontrollera slirhastigheten genom att använda komponenterna i en befintlig, produktionssatt Scania drivlina och om det finns en nyckelparameter i hårdvaran som tydligt begränsar regleringens prestanda. Kopplingens temperatur och slitning anses vara utanför ramen för detta examensarbete och behandlas inte i denna rapport. Som första steg i utvecklingen konstrueras en MBS-modell av drivlinan i fråga. Fortsättningsvis implementeras två reglerstrukturer, nämligen fuzzy-reglering och tvåfrihetsgradsreglering genom att använda modellbaserad utveckling. För att utreda prestandan i dagens system implementeras båda reglerstrukturerna i en lastbil där verklig provning utförs. För att hitta den begränsande faktorn utförs en parametervariation i den utvecklade modellen istället för i en lastbil, vilket sparar både tid och minskar kostnaden. I det här examensarbetet har det visats att momentdynamiken från dieselmotorn kan dämpas ut med fyrtio till åttio procent i amplitud genom att slira på kopplingen och att den implementerade reglering ger en acceptabel prestanda för växlarna sju till tolv i existerande hårdvara. Den utförda parametervariationen visar att fördröjningen mellan beräknad styrsignal och faktisk aktuering är mest begränsande och att en eliminering av denna möjliggör stabil reglering på första växeln. Kopplingsslirregleringskonceptet visar stor potential men sätter höga krav på hårdvara; inte minst aktueringsfördröjningen om regleringen ska användas på alla växlar. Med existerande drivlina är dock regleringen fullt implementerbar sju till och med tolv.
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Brice, Xavier. "There's many a slip : the writing of Nostromo." Thesis, University of Kent, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.252539.
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Abd, Rahman Nur 'aliaa. "Wall slip in pipe rheometry of multiphase fluids." Thesis, University of Manchester, 2013. https://www.research.manchester.ac.uk/portal/en/theses/wall-slip-in-pipe-rheometry-of-multiphase-fluids(e631bc91-5b5f-4301-9dd1-6410a08d54b4).html.
Full textAbstract:
Multiphase fluids are widely available in our everyday life. Many of the materials we use and eat every day are classed as multiphase and characterisation of their properties is required to improve quality and manufacture. Being typically non-Newtonian fluids, rheological characterisation of multiphase fluid systems is indeed a complex procedure. Apparent wall slip, or more precisely wall depletion effect near the wall, is an important phenomenon which often occurs in the flow of multiphase fluids in pipes. Wall slip has its own advantages and disadvantages in the processing and pipe flow of multiphase fluids. One of the main problems it causes is the underestimation of the viscosity and the true flow curve of the fluids reported during experimental measurements. Standard correction methods often account for this effect, but there have been many instances reported where the data does not comply with the technique. This study aimed to present a wall slip analysis of a selection of non-Newtonian multiphase fluids during flow in pipes. A pipe rheometry rig was specially designed and built for the purpose of the research which includes four interchangeable pipes with different diameters; three sets of pressure and temperature transducers located at three different points along the test section; an electronic mass balance; and a PC data logger for control, monitoring and data collection purposes. Three distinct non-compliant multiphase fluids were chosen for study i.e. ice cream, citrus dietary fibre (CDF) suspensions and magnesium silicate slurries. The experiments were carried out in pressure driven shear flow. The flow data were analysed using the classical Mooney method along with a Tikhonov regularisation-Mooney method. For ice cream flow data, the analysis indicated that significant apparent wall slip occurred in all flows and there was a small but significant increase in the temperature near the wall which indicated the occurrence of viscous heating phenomenon. Energy balances indicated that the apparent wall slip effect was not due to the existence of a thin slip layer of rarefied low viscosity fluid next to the wall. It was found that the results were better understood as being the result of a moderately thick layer of slightly heated ice cream next to the wall. Mooney and Tikhonov regularisation-Mooney methods were confirmed to be incompatible with the wall slip behaviour of CDF suspensions and magnesium silicate slurries. The incompatibility of the method to analyse wall slip is attributed to the inconsistent ratio of Vslip/τw and δ/μslip at constant wall shear stress. It is concluded that this was due to the microstructure changes and shear-induced re-orientation of the particles in CDF suspensions and magnesium silicate slurries during flows which resulted in the inconsistency of the slip layer thickness and consequently affected the wall slip characterisation process. The principal contribution of this research work is to present a comprehensive wall slip analysis in pipe rheometry of multiphase non-Newtonian fluids, which are of particular interest in engineering process design.
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Bekaert, David Peter Sonja. "Interferometric synthetic aperture radar for slow slip applications." Thesis, University of Leeds, 2015. http://etheses.whiterose.ac.uk/11659/.
Full textAbstract:
Over the last two decades, Slow Slip Events (SSEs) have been observed across many subduction zones, primarily through continuous GNSS networks. SSEs represent shearing of two tectonic plates, at much slower rates than earthquakes but more rapidly than plate motion. They are not dangerous in themselves, but change the stress field and can potentially trigger devastating earthquakes. While highly valuable, GNSS networks at most locations lack the spatial-resolution required to describe the spatial extent of the slow slip at depth. A better constraint of slow slip at depth in combination with other observations from seismology could be essential in addressing key research questions. These include: “Why do slow slip events occurs in some regions and not others?”, “What drives slow slip events?”, “Do slow slip events delay the occurrence of devastating earthquakes?”, and “Can slow slip events trigger devastating earthquakes?”. Interferometric Synthetic Aperture Radar (InSAR) is an established and attractive technique to study surface displacements at high-spatial resolution. Until now, InSAR has not been fully exploited for the study of SSEs. Here, I provide the necessary InSAR methodology, and further demonstrate the use of InSAR for static and time-dependant slow slip modelling. My developments have a direct benefit for various other applications such as earthquake cycle processes. I Specifically address the following two challenges which limit the wide uptake of InSAR: (1) Decorrelation noise introduced by changing backscattering properties of the surface and a change in satellite acquisition geometry, making it difficult to correctly unwrap meaningful signal. I address this problem by applying existing advanced time-series InSAR processing methods. (2) Atmospheric delays masking the smaller slow slip signal. These are mainly due to spatial and temporal variations in pressure, temperature, and relative humidity in the lower part of the troposphere, which result in an apparent signal in the InSAR data. Different tropospheric correction methods exist, all with their own limitations. Auxiliary data methods often lack the spatial and temporal resolution, while the phase-based methods cannot account for a spatially-varying troposphere. In response, I develop a phase-based power-law representation of tropospheric delay that can be applied in the presence of deformation and which accounts for spatial variation of tropospheric properties. I demonstrate its application over Mexico, where it reduces tropospheric signals both locally (on average by ~0.45 cm for each kilometer of elevation) and the long wavelength components. Moreover, I provide to the research community a Toolbox for Reducing Atmospheric InSAR Noise (TRAIN), which includes all the state-of-the-art correction methods, implemented as opensource matlab routines. When comparing these methods, I find spectrometers give the largest reduction in tropospheric noise, but are limited to cloud-free and daylight acquisitions. I also find that all correction methods perform ~10-20% worse when there is cloud cover. As all methods have their own limitations, future efforts should aim at combining the different correction methods in an optimal manner. Additionally, I apply my InSAR methodology and power-law correction method to the study of the 2006 Guerrero SSE, where I jointly invert cumulative GNSS and InSAR SSE surface displacements. In Guerrero, SSEs have been observed in a “seismic gap”, where no earthquakes have occurred since 1911, accumulating a seismic potential of Mw 8.0-8.4. I find slow slip enters the seismogenic zone and the Guerrero Gap, with ~5 cm slip reaching depths as shallow as 12 km, and where the spatial extent of the slow slip collocates on the interface with a highly coupled inter-SSE region as found from an GNSS study. In addition, slow slip decreased the total accumulated moment since the previous SSE (4.7 years earlier) by ~50% Over time and while accounting for SSEs, the moment deficit in the Guerrero Gap increases each year by Mw ~6.8. Therefore I find that the Guerrero Gap still has the potential for a large earthquake, with a seismic potential of Mw ~8.15 accumulated over the last century. Finally, I show the application to use InSAR for time-dependant slow slip modelling. From a simulation of the 2006 SSE, I demonstrate that InSAR is able to provide valuable information to constrain the spatial extent of the slow slip signal. With a future perspective of continued high repeat acquisitions of various SAR platforms, my expansion of the Network Inversion Filter with InSAR will become a powerful tool for investigating the spatio-temporal correlation between slow slip and other phenomena such as non volcanic tremor. Moreover, this approach can apply to earthquake cycle processes. Studying the broader earthquake cycle will further our knowledge of seismic hazard and increase our resilience to such events.
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S, Suharsono. "Analytical study of fluid flows with slip boundary." Thesis, Curtin University, 2012. http://hdl.handle.net/20.500.11937/2281.
Full textAbstract:
One of the important scientific research focuses worldwide has been on the study of behavior of materials at micro and nano-scales. Continuing theoretical and technological development in this area has led to the development of many biological and engineering devices and systems which involve fluid flow through micro-channels, referred to microflows. Typical examples include fuel cells, drug delivery systems and energy conversion devices.As the functional characteristics of micro-systems depend, to a large degree, on the behavior of fluid flow in the micro-channels, it is extremely important to study microflows. In recent years, many investigations were carried out to study various flow problems of Newtonian and non-Newtonian fluids under the steady state condition. However exact solutions to many flow problems of Newtonian fluids in micro-channels under the unsteady condition have not been developed and investigated. Hence, in this project, we study the unsteady flow of incompressible Newtonian fluids through rectangular and elliptic micro-channels with boundary slip.For the unsteady flow through micro-channels of rectangular cross-section, the governing equations are constructed and formulated in the rectangular coordinate system. Then by using Fourier series expansion and separation of variables, the governing partial differential equation for the velocity field is successfully reduced to two simpler families of boundary value problems which are then solved analytically. From the derived exact solution of the velocity field, the transient flow rate and the stress field in the fluid are subsequently derived. An investigation is then conducted to study the behaviour of microflows in rectangular channels. Various interesting results, showing the influence of boundary slip and cross-section geometry (width to depth ratio) on the flow behaviour and efficiency, have been obtained and presented in the thesis.For the unsteady flow through micro-channels of elliptic cross section, the complete set of governing equations, including the partial differential equation and the boundary conditions, are formulated in elliptic cylindrical coordinates. Then by using Fourier series expansion and separation of variables, the partial differential equation for the velocity field is successfully reduced to two families of Mathieu type equations which are then solved analytically subject to the symmetric condition and the slip boundary condition. Exact solutions for the transient flow rate and the stress field in the fluid are then derived subsequently. The solutions are expressed in terms of the Mathieu functions and the modified Mathieu functions, which are in series form and are determined by computing their characteristic numbers and the coefficients of the series. A numerical investigation is then conducted to demonstrate the flow behavior of fluids in elliptic micro-channels.