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 25 for “"frictional heating"”.
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The role of frictional heating in the development of catastrophic landslides
In this work, a new thermo-mechanical model is developed by improving on an existing one, applicable to large deep seated landslides and rockslides consisting of a coherent mass sliding on a thin clayey layer. The considered time window is that of catastrophic acceleration, starting at incipient …
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F-region Dusk Ion Temperature Spikes at the Equatorward Edge of the High Latitude Convection Region
… were the result of electric elds increasing the frictional heating between ions and neutrals. By then examining geophysical data, it was found that these events were temporal and related to changes in magnetic indices. One possible explanation for the observations is that the electric eld is at …
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On developing a graphitic white iron for metal-to-metal wear systems
… layers were formed on the wearing surface due to frictional heating and surface deformation. These white layers were extremely brittle and could be fractured easily during use, which in turn led to micro-galling defects that caused parts leakage. Increasing thermal diffusivity of the material was …
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An Evaluation Of UHPLC-MS Technology Encompassing Elevated Temperatures, Low Viscosity Operation and Recently Developed Stationary Phase Materials
… for installation, and due to the effects of frictional heating associated with operation at ultra-high pressures. An attempt to reduce the effect of frictional heating by modifying the column hardware was evaluated, however only slight improvements were observed. This system has benefits to …
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The effects of isothermal deformation and annealing on the microstructure of nickel-aluminum-bronze propeller material
… and sticking friction result in a combination of frictional heating and adiabatic heating due to plastic deformation. A stirring effect results in the formation of a zone of severe shear deformation and local temperatures approaching 90% of the melting temperature. FSP results in local …
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Quantitative assessment of the frictional ignition resistance of metals in high-pressure oxygen
… material index for selecting alloys resistant to frictional ignition in high-pressure oxygen environments. A previous ignition-resistance metric proposed by NASA WSTF varies strongly and unpredictably with test conditions, thus limiting its usefulness. The material index developed here …
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Thermal analysis of sliding contact systems using the boundary element method
… is developed to determine the distribution of frictional heat and the ensuing surface or subsurface temperature rise caused by frictional heating between sliding solids. The theoretical model consists of two semi-infinite substrates each coated with a film of arbitrary thickness and thermal …
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Analytical Modeling for Sliding Friction of Rubber-Road Contact
… Two novel approaches are discussed and compared. Frictional shear stress is obtained from the energy dissipated at the contact interface due to the elastic deformations of rubber block at different length scales. Contact mechanics theories based on continuity approach combined with stochastic …
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Incoherent Scatter Radar Observations of Dynamic Ion Composition Changes at High Latitudes during Geomagnetic Storms
… and F region molecular ion increases due to frictional heating. Other results include rather large increases of F region molecular ion concentrations after sunrise during storms, a quantitative analysis of the crossover altitude dependence on effective electric field, and several observations …
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Geochemical and petrological investigation into the magmatic system at Soufrière Hills Volcano, Montserrat.
… resorbed into the partial melt generated during frictional heating (>1000 °C) at the slip surface as a peraluminous partial melt recrystallised. The shear zones provide evidence for degassing and an insight into controls on eruption style.
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Exploring Controls on the Flow Dynamics of Devon Ice Cap using a Basal Friction Inversion
… heat loss which is not countered by additional frictional heating as the weakened till provides less resistance to flow. The termination of this surge could therefore result from water withdrawal from the underlying till without the need for changes to geometry. Glaciers defined as pulsing …
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The effects of hardness, toughness, microstructure and thermomechanical heating on the erosion of ceramic and ultrahard materials
… from a combination of plastic deformation and frictional heating under high contact stresses. The amount of heat dissipated is determined by the erodent and target hardness and friction coefficients. The rate at which the heat diffuses away from the impact zone is determined by the thermal …
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Applied Thermoelectric Solutions
… and electric automotives. The assembly converts frictional heating from vehicle brake pads to electrical energy. This conversion from mechanical energy to electrical energy can be used for a portion of the power input into a vehicle battery, thus improving hybrid and electrical automotive …
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A Comprehensive Study Of Nonlinear Effects Of Coupling Materials In Ultrasound Infrared Imaging
… become visible in the infrared imaging through frictional heating associated with the application of a short pulse of low-frequency ultrasound. The technique uses pulses of ultrasonic excitation applied to a sample for a fraction of a second. The heating at the crack is then captured by …
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Material Flow Behavior in Friction Stir Welding
… and vertical deformation. Material flow and frictional heating in FSW are also investigated using a three-dimensional numerical model. Two mechanical boundary conditions are investigated, including 1) a sticking constant velocity, and 2) a slipping variable shear stress model. The constant …
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Fundamental studies of the tribological behavior of thin polymeric coatings in fretting contact using infrared and photo/video techniques
… shaker. Surface temperatures generated by frictional heating were measured during fretting contact using an infrared microscope. A photo/video technique was developed to view the fretting contact interface during an experiment and to measure the size and distribution of real area(s) of …
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Speed and Temperature Effects in the Energy Absorption of Axially Crushed Composite Tubes
… stresses in the hoop direction of the tube and frictional heating in the crush zone. Speed sensitivity of the energy absorption has been determined over a range of temperatures and various features of these responses related to the responses of the material properties. Frictional temperature …
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Prediction of the running torque of instrument ball bearings at high speed under combined radial and axial loads
… of supplementary topics, it was determined that frictional heating was insignificant during the conduct of the torque tests which had a duration of approximately two minutes. All tests were at ambient temperature. All tests conducted were with oil lubricant and ribbon retainer ba1l bearings. …
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Auroral Ion Upflows: Sources, High Altitude Dynamics, and Neutral Wind Effects
… have a range of potential sources including frictional heating, electron precipitation, neutral winds, and higher-altitude density cavities. The unique signatures and detailed evolution of these upflows are examined through the use of Incoherent Scatter Radar data and a sophisticated …
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Heat Generation and Transfer in Additive Friction Stir Deposition
… mechanisms of plastic deformation and sliding frictional heat generation. The magnitude of these mechanisms, and hence the total applied thermal power, implicitly depend on the thermal state of the system, forcing power input to become a dependent variable. This is not the case in other 3D …
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