Home About us Contact
|
Home About us Contact | ||
|
|
||
Wear Analysis (wear + analysis)
Selected AbstractsTribological Studies of a Zr-Based Glass-Forming Alloy with Different States,ADVANCED ENGINEERING MATERIALS, Issue 11 2009Feng Jiang Abstract The tribological characteristics of a glass-forming alloy, Zr52.5Cu17.9Ni14.6Al10.0Ti5.0, in atomic percent (at.%, Vit 105), with different microstructural states have been investigated. Friction and wear studies were conducted using a ball-on-flat reciprocating sliding apparatus against an AISI E52100 bearing steel under dry condition. The observed wear resistance in an ascending order is: the deformed, creep-tested, and as-cast states. Wear analyses suggested that the wear processes of glass-forming alloys involved abrasion, adhesion, and oxidation. The differences in hardness, free volume, and brittleness in different states significantly affected the friction and wear behaviors of the glass-forming alloys. [source] An in vitro wear study of posterior denture tooth materials on human enamelJOURNAL OF ORAL REHABILITATION, Issue 5 2001Y. Abe This in vitro study evaluated the wear effects of five posterior denture tooth materials on human enamel. The tooth specimen was cusp shaped and enamel specimen was formed as a 10 Ç 10 Ç 5 mm plate. All material-enamel combinations were tested using a machine designed to produce sliding contact 20 Ç 104 times at 60 cycles min,1 and a 4-mm sliding distance per stroke in the bucco-lingual direction under a load of 1 kg. Wear analysis was measured as the total height loss of each combination. In addition, the surface roughness (Ra) of each worn specimen was also evaluated. The least total height loss occurred with poly (methyl methacrylate) (PMMA) enamel pair, and the greatest did with porcelain (Po)-enamel pair. The lowest compound Ra value was measured in high-strength resin (HR)-enamel pair, and the highest in Po-enamel pair. These findings suggest that the best combination is PMMA-enamel, and the poorest combination is Po-enamel. [source] Polyethylene cross-linking by two different methods reduces acetabular liner wear in a hip joint wear simulatorJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 5 2003Darryl D. D'Lima Advances in cross-linking have led to the development of wear resistant ultrahigh molecular weight polyethylene for total joint replacement. This study compared wear reduction by two different cross-linking methods as measured in a hip wear simulator. One highly cross-linked polyethylene was treated with 7.5 Mrad gamma irradiation with post-irradiation annealing and a sterilization dose of 2.5 Mrad (10 Gamma), while the other used 9.5 Mrad warm irradiation with 10 MeV electron-beam (9.5 EB). Liners of the same design, made from nominally cross-linked (gamma sterilized) polyethylene were also tested. Gravimetric wear analysis was performed every 500,000 cycles for 5,000,000 cycles. After correcting for weight gain due to water absorption, the nominally cross-linked liners demonstrated mean wear rates of 15.7 (±1.7) and 12.5 (±1.0) mg/million cycles. Both highly cross-linked polyethylene liners demonstrated significantly less wear than their respective controls (with mean wear rates of 1.5 (±1.2) and ,1.4 (±1.5) mg/million cycles). The 9.5 EB liners gained weight presumably due to increased fluid absorption, in addition to that measured in loaded,soaked control implants. Any wear occurring was therefore assumed to have been more than offset by weight gain. Highly cross-linked polyethylene was significantly more wear resistant than non- or nominally cross-linked polyethylene. The differences in wear rates between the two highly cross-linked polyethylene designs (9.5 EB or 10 Gamma) are probably too small to be clinically significant. © 2003 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved. [source] Preventive effect of iron gel with or without fluoride on bovine enamel erosion in vitroAUSTRALIAN DENTAL JOURNAL, Issue 2 2010MG Bueno Abstract Background:, The aim of this study was to evaluate the preventive effect in vitro of experimental gel containing iron and/or fluoride on the erosion of bovine enamel. Methods:, To standardize the blocks (n = 80), specimens (4 × 4 mm) were previously selected to measure the initial microhardness. The blocks were randomly allocated into four groups of 20 samples each: C (control, placebo gel); F (fluoride gel, 1.23% NaF); Fe (iron gel, 10 mmol/L FeSO4) and F + Fe (fluoride + iron gel). The gels were applied and removed after 1 minute. The blocks were then submitted to six alternating remineralization and demineralization cycles. The beverage Coca-Cola® (10 minutes, 30 mL) was used for demineralization, and artificial saliva (1 hour) for remineralization. The effect of erosion was measured by wear analysis (profilometry). Data were analysed by ANOVA and the Tukey test for individual comparisons (p <0.05). Results:, The mean wear (± SD, ,m) was C: 0.94 ± 0.22; F: 0.55 ± 0.12; Fe: 0.49 ± 0.11 and F + Fe: 0.55 ± 0.13. When the experimental gels were used, there was statistically significant reduction in enamel wear in comparison with the control (p <0.001). However, the experimental gels did not differ significantly among them. Conclusions:, The gels containing iron with or without fluoride are capable of interfering with the dissolution dental enamel in the presence of erosive challenge. [source] | ||||||||||