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Your search keyword '"Blanchet, Thierry A."' showing total 86 results
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86 results on '"Blanchet, Thierry A."'

64. Demonstration of the Feasibility of High Temperature Bearing Lubrication From Carbonaceous Gases.

Author

RENSSELAER POLYTECHNIC INST TROY NY DEPT OF MECHANICAL ENGINEERING, Blanchet, Thierry A., Sawyer, W. G., RENSSELAER POLYTECHNIC INST TROY NY DEPT OF MECHANICAL ENGINEERING, Blanchet, Thierry A., and Sawyer, W. G.

Abstract

Research has been conducted on silicon nitride pin-on-disk sliding contacts at temperatures of up to 520 deg C, and four-ball rolling contacts with silicon nitride balls and 52100 steel or silicon nitride races at 590 deg C. These tests were conducted in a variety of gaseous environments in order to determine the effects of simulated engine exhaust gas on the carbonaceous gas decomposition lubrication scheme. In rolling tests with steel races and exhaust gas the wear track depth was roughly half that of tests run in nitrogen gas alone. The deposition of lubricous microcrystalline graphitic carbon on the rolling surfaces, generated from the carbon monoxide within the exhaust gas mixture, was verified by microfocused Raman spectroscopy. Ten-fold reductions in rolling wear could be achieved by the exhaust gas atmosphere in cases where water vapor was removed or not present. The exhaust gas mixture alone was not found to provide any lubricating effect on silicon nitride sliding contacts, where the rate of wear greatly exceeds the rate of carbon deposition. Directed admixture of acetylene (as low as 5% of the exhaust gas flow rates), has provided reductions in both wear volume and coefficient of friction by factors of 60X and 20X respectively for sliding contacts during the initial 80m of sliding distance. Exhaust gas atmosphere with the acetylene admixture provided 650X reductions in steady state wear rate compared to that measured for sliding contacts in dry N2. Such acetylene admixture also augments the ability of the exhaust gas atmosphere to lubricate high-temperature rolling contacts, with up to 25-fold reductions in wear track depth compared to those measured in the presence of N2 alone.

Published
1996

81. Assessment of Amorphous Carbon Coating for Artificial Joints Application.

Author

Ajayi, O. O., Shi, B., Liang, H., Fenske, G. R., Soppet, M. J., Erdemir, A., and Blanchet, Thierry

Subjects
ARTIFICIAL joint bearings, BEARINGS (Machinery), FRICTION, CERAMICS, TRIBOLOGY
Abstract

Replacement of diseased or damaged human joints with artificial ones is now a common surgical procedure with a very high success rate. The hip and the knee are the two most replaced joints. Currently, these artificial joints only last 10-15 years before failing by aseptic loosening due to periprosthetic osteolysis. The root cause of osteolysis has been traced to the body's response to the presence of polyethylene wear debris, which is one of the articulating bearing surfaces. Thus, elimination or reduction of wear at the rubbing interface of the joint is expected to prevent or at least delay onset of osteolysis, thereby increasing joint reliability and durability. Highly wear-resistant and biocompatible bearing surfaces can lower debris generation in artificial joints. In the present study we evaluated the friction and wear performance of newly developed Argonne carbon coatings and two ceramic materials (alumina and zirconia) as possible joint-bearing surfaces. Tests were conducted with a reciprocating pin-on-plate contact configuration using bovine serum as lubricant. Wear of the ceramic materials was substantially (two orders of magnitude) less than that of polyethylene, and the wear of the carbon coating was several times less than that of the ceramic materials. Results of the present study demonstrate that a plausible approach to enhance the durability of artificial joints is the engineering of the bearing surfaces with a highly wear-resistant coating. [ABSTRACT FROM AUTHOR]

Published
2005
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84. Modeling birefringence in SiO2 glass fiber using surface stress relaxation: Erratum.

Author

Hausmann, Bronson David, Blanchet, Thierry A., and Tomozawa, Minoru

Subjects
*GLASS fibers, *STRESS relaxation (Mechanics), *HEAT treatment, *OPTICAL fibers, *RESIDUAL stresses
Abstract

In the appendix of the above manuscript,1 an equation used to model residual stress in optical fibers following heat treatment under stress is developed. [Extracted from the article]

Published
2021
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