The Experts below are selected from a list of 588 Experts worldwide ranked by ideXlab platform
Cristiano Collettini - One of the best experts on this subject based on the ideXlab platform.
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faults smooth gradually as a function of slip
Earth and Planetary Science Letters, 2011Co-Authors: Emily E Brodsky, Jacquelyn J Gilchrist, Amir Sagy, Cristiano CollettiniAbstract:Abstract Geometry and roughness of fault surfaces plays a central role in the dynamics and kinematics of faulting. Faults smooth with increasing slip, but the degree of the smoothing has not previously been well-constrained for natural faults. We measure the roughness as a function of displacement for a suite of 16 faults with cumulative offsets ranging from 0.1 m to approximately 500 m. We find that slip parallel roughness evolves gradually with slip. For instance, for segments of length 0.5 m, H ≈ 2 × 10 −3 D −0.1 where H is the RMS roughness and D is the displacement on the fault strand with both quantities measured in meters. The gradual nature of the smoothing is robust to varying lithology and erosion. The weak function implies a decrease in the rate of gouge formation for a model with increasing slip for a model in which gouge is generated by abrading an Asperity Tip. The relatively gradual evolution of roughness could be explained by lubrication by the accumulated gouge that mitigates the abrasional smoothing that occurs during slip and/or re-roughening processes.
Ken Tsugane - One of the best experts on this subject based on the ideXlab platform.
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experimental analysis of pad wear response effect on removal rate variations in tungsten chemical mechanical polishing
Journal of The Electrochemical Society, 2010Co-Authors: Yohei Yamada, Masanori Kawakubo, Kazunori Kadomura, Osamu Hirai, Takahiro Sugaya, Ken TsuganeAbstract:We investigated the effects of the pad surface response during polishing and conditioning on the removal rate variation in a tungsten chemical mechanical polishing (CMP) process. We examined the coefficient of friction (COF) to identify the tribology of the pad conditioning. The variation in the removal rate was dependent on the COF during conditioning. We also evaluated the effects of diamond edge degradation of the pad conditioner disk on its cutting ability from the viewpoint of mechanical wear. The results showed that the decline in pad wear rate was caused by a decrease in the cutting ability as the diamond sharp edges rounded off, while the diamond contact area with the pad surface depended little on the diamond abrasive degradation. Furthermore, we demonstrated the usefulness of measuring the height ratio of the Asperity called "top surface area (TSA) ratio" as an appropriate topographical parameter to study the dependence of COF during conditioning on the decay of the removal rate. We present a clear correlation between the pad wear rate degradation and the TSA ratio after CMP to elucidate an increase in the conditioning COF related to truncation of the Asperity Tip by wear and plastic deformation.
Ravi V. S. Kanda - One of the best experts on this subject based on the ideXlab platform.
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LINEAR AND NONLINEAR MODELING OF Asperity SCALE FRICTIONAL MELTING IN BRITTLE FAULT ZONES
2003Co-Authors: Ravi V. S. Kanda, Ravi V. SAbstract:Study of pseudotachylytes (PT) (frictional melts) can provide information on the physical and chemical conditions at the earthquake source. This study examines the influence of Asperity-scale fault dynamics on Asperity temperature distribution, and therefore, the potential for frictional melting to occur. Frictional melting occurs adiabatically, and is initiated between opposing Asperity Tips during fault slip. Our model considers 2-D heat conduction in elastic, isotropic, hemispherical asperities, with temperature dependent thermal properties. The only heat source is a point heat flux pulse at the Asperity Tip. The non-linear problem was solved using the δ-form of Newton-Kantorovich procedure coupled with the δ-form of Douglas-Gunn two level finite difference scheme, while the linear problem required only the latter method. Results for quartz and feldspar indicate that peak temperatures can reach melting point values for typical Asperity sizes (1-100 mm), provided that contact (frictional) shear stress is sufficiently high. For any Asperity size, the temperature distribution peak becomes insignificant by the time it reaches the Asperity center. These results imply that much of Asperity scale melting is highly localized, which may explain why most PT veins in the field are usually very thin. However, in some cases, successive Asperity encounters may generate temperature increases large enough t
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LINEAR AND NONLINEAR MODELING OF Asperity SCALE FRICTIONAL MELTING
2003Co-Authors: Ravi V. S. KandaAbstract:Study of pseudotachylytes (PT) (frictional melts) can provide information on the physical and chemical conditions at the earthquake source. This study examines the influence of Asperity-scale fault dynamics on Asperity temperature distribution, and therefore, the potential for frictional melting to occur. Frictional melting occurs adiabatically, and is initiated between opposing Asperity Tips during fault slip. Our model considers 2-D heat conduction in elastic, isotropic, hemispherical asperities, with temperature dependent thermal properties. The only heat source is a point heat flux pulse at the Asperity Tip. The non-linear problem was solved using the δ-form of Newton-Kantorovich procedure coupled with the δ-form of Douglas-Gunn two level finite difference scheme, while the linear problem required only the latter method. Results for quartz and feldspar indicate that peak temperatures can reach melting point values for typical Asperity sizes (1-100 mm), provided that contact (frictional) shear stress is sufficiently high. For any Asperity size, the temperature distribution peak becomes insignificant by the time it reaches the Asperity center. These results imply that much of Asperity scale melting is highly localized, which may explain why most PT veins in the field are usually very thin. However, in some cases, successive Asperity encounters may generate temperature increases large enough to trigger the massive melting inferred from typical PT exposures. Significant differences were observed between the results of the linear and nonlinear models
Emily E Brodsky - One of the best experts on this subject based on the ideXlab platform.
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faults smooth gradually as a function of slip
Earth and Planetary Science Letters, 2011Co-Authors: Emily E Brodsky, Jacquelyn J Gilchrist, Amir Sagy, Cristiano CollettiniAbstract:Abstract Geometry and roughness of fault surfaces plays a central role in the dynamics and kinematics of faulting. Faults smooth with increasing slip, but the degree of the smoothing has not previously been well-constrained for natural faults. We measure the roughness as a function of displacement for a suite of 16 faults with cumulative offsets ranging from 0.1 m to approximately 500 m. We find that slip parallel roughness evolves gradually with slip. For instance, for segments of length 0.5 m, H ≈ 2 × 10 −3 D −0.1 where H is the RMS roughness and D is the displacement on the fault strand with both quantities measured in meters. The gradual nature of the smoothing is robust to varying lithology and erosion. The weak function implies a decrease in the rate of gouge formation for a model with increasing slip for a model in which gouge is generated by abrading an Asperity Tip. The relatively gradual evolution of roughness could be explained by lubrication by the accumulated gouge that mitigates the abrasional smoothing that occurs during slip and/or re-roughening processes.
Yohei Yamada - One of the best experts on this subject based on the ideXlab platform.
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experimental analysis of pad wear response effect on removal rate variations in tungsten chemical mechanical polishing
Journal of The Electrochemical Society, 2010Co-Authors: Yohei Yamada, Masanori Kawakubo, Kazunori Kadomura, Osamu Hirai, Takahiro Sugaya, Ken TsuganeAbstract:We investigated the effects of the pad surface response during polishing and conditioning on the removal rate variation in a tungsten chemical mechanical polishing (CMP) process. We examined the coefficient of friction (COF) to identify the tribology of the pad conditioning. The variation in the removal rate was dependent on the COF during conditioning. We also evaluated the effects of diamond edge degradation of the pad conditioner disk on its cutting ability from the viewpoint of mechanical wear. The results showed that the decline in pad wear rate was caused by a decrease in the cutting ability as the diamond sharp edges rounded off, while the diamond contact area with the pad surface depended little on the diamond abrasive degradation. Furthermore, we demonstrated the usefulness of measuring the height ratio of the Asperity called "top surface area (TSA) ratio" as an appropriate topographical parameter to study the dependence of COF during conditioning on the decay of the removal rate. We present a clear correlation between the pad wear rate degradation and the TSA ratio after CMP to elucidate an increase in the conditioning COF related to truncation of the Asperity Tip by wear and plastic deformation.
