Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 56 for “"friction force"”.
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Modeling friction force avalanches in molybdenum disulfide and spiking neuronal avalanches in mouse cortex
Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2023-12-04 without embargo terms
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Quantum non-contact friction in resonant dielectric media
We compute the non-contact friction force induced between two isotropic planar dielectric slabs which obey a plasma model dielectric function using scalar electromagnetism. All computations are carried out at zero temperature. Strong constraints on the integration parameters which define the …
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Frictional behavior of polymers: the transition from static to kinetic conditions
… in squeaking dashboards is caused by the drop in friction force during the transition from static to kinetic conditions between the mating plastic components of the dashboard. The frictional behavior of a polymer determines whether there is a drop in friction force during this transition. This …
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Understanding the friction between human fingers and contacting surfaces
Friction tests were carried out to assess the friction between a human finger and contacting surface, in different conditions. Tests examined the effect of normal force, the area of contact, the effect of triangular and rectangular cross-section ridges and the effect of moisture. The tests found …
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High Speed Atomic Force Microscopy Techniques for the Efficient Study of Nanotribology
… length scales, it is crucial to understand friction and wear at the nanoscale (nanotribology) especially at technically relevant sliding velocities. Accordingly, three novel techniques have been developed to study nanotribology, leveraging recent advances in high speed AFM. The first method …
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An investigation of friction and wear mechanisms in selected thermoplastics
… sliding trials. In each case a higher rate of friction force increase coincided with debris formation. No debris was produced in the ultra-high molecular weight polyethylene dry sliding trials, and the friction force trace was flat. An SEM analysis of the polycarbonate and rigid PVC wear tracks …
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Development, Evaluation and Improvement of Correlations for Interphase Friction in Gas-Liquid Vertical Upflow
… an improved method of modelling the interphase friction in two-phase vertical flow in nuclear thermal-hydraulic codes. An improved method of modelling interphase friction should allow for better prediction of pressure gradient, void fraction and the phasic velocities. Data has been acquired from …
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An Experimental Study Of Atomic Scale Friction And Adhesion For 2d And Layered Materials: The Effects Of Interfacial Contact, Compliance, And Commensurability
While frictional behavior has been studied for millennia, trial-and-error approaches to materials selection for sliding systems remain prevalent due to a lack of understanding of the underlying mechanisms of friction. This thesis discusses uses of atomic force microscopy to probe the atomic-scale …
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Nonlinear estimation for condition monitoring of advanced gas-cooled nuclear reactor cores
… provides, through the magnitude of its friction component, information relating to the condition of the graphite bricks. Therefore, the condition monitoring of an AGR leads to the estimation of the friction force resulting from the interaction of the fuel assembly and the core channel. …
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Infrared measurements of surface temperatures during oscillating/fretting contact with ceramics
Surface temperatures generated by friction during osculating/fretting contact were measured using an infrared microscope coupled to a digital data acquisition system developed at Virginia Polytechnic Institute and State University. The contact geometry consisted of a stationary test specimen loaded …
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Friction and degradation of rubber coatings under fretting conditions
A fundamental study was conducted to analyze the friction and degradation mechanisms of thin rubber coatings used as fretting corrosion inhibitors. Two elastomers, polyurethane and styreneethylene-butylene (SEBS), were investigated. The mechanisms of wear were studied by analyzing wear scars with …
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Micro Surface Texturing for Friction Control
… has gained momentum as a way to control the friction which is involved in various applications and systems, such as components of internal combustion engines, dies and punches of the metal forming processes and Micro-electrical-mechanical Systems (MEMS). This dissertation demonstrates that …
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An investigation of glass cartridge siliconization processes for improved device performance
… silicone profile that can significantly reduce friction force variation within a cartridge during device use. An Insulin pen delivers Insulin to patients by the mechanical pushing of a rubber stopper through a cylindrical glass cartridge forcing the Insulin through a hypodermic needle at the cap …
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Effect of friction and control parameters on the tracking accuracy of a target seeker
… gimbaled platform, an important variable is the friction induced by the preloaded bearings, and by the short wires which connect the target detector with the rest of the seeker's electronics. This friction force is nonlinear and sufficiently large enough such that accurate position tracking of a …
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A study of mechanical behaviour of the double-row tapered ring bearing for the main shaft of a direct-drive wind turbine
… have been proposed for calculating the contact force and pressure distribution of double-row TRBs. Nevertheless, most of the existing studies failed to consider angular misalignment between the inner and outer rings as well as the friction force between the rollers and raceways. A fatigue life …
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Flow in thin regions bounded by structured and porous surfaces : applications to load bearings
… of surface roughness on the load capacity and friction force of hydrodynamic bearings has received considerable interest from scientists and engineers. Surfaces of most engineered materials are textured at some level either deliberately to achieve some desired effect or produced by wear and …
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Minimization of stresses and pressure surges in pipes using nonlinear optimization.
… pressures in liquid-filled piping systems. The friction force is included in the equations of motion for the fluid and the pipe wall. The maximum pressure and maximum stress at any point along the length of the pipe are evaluated for the entire simulation time. A nonlinear search technique has …
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The effect of molecular weight on the behavior of polystyrene coated steel disks under fretting conditions
… ranged from 100 ~m to 500 ~m. Coating life and friction force were measured. Coatings of <Mw>=207,700 showed maximum life at all amplitudes. Friction remained constant for all tests, and increasing amplitude decreased life. Toluene-cast coatings had slightly shorter lives and more coating racks …
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Investigations of the Tribological Effects of Engine Oil Dilution by Vegetable and Animal Fat Feedstock Biodiesel on Selected Surfaces
… tested in a pinon-disk tribometer. In-process friction force and temperature changes are observed and specific wear on the tested surface and dilution effects on viscosity are measured. The oxidative stability of diluted engine oils is also assessed by observation. Experimental results suggest …
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The effects of thin polymeric surface films on fretting corrosion
… significance on the measured minimum fretting friction force.
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