Abrasion (mechanical)

About: Abrasion (mechanical) is a research topic. Over the lifetime, 14392 publications have been published within this topic receiving 129530 citations. The topic is also known as: scratching & scuff.

Improved accuracy of U-Pb zircon ages by the creation of more concordant systems using an air abrasion technique

Abstract: Abrasion combined with an improved paramagnetic separation technique eliminates 90 to 100 percent of discordance so that ages of unprecedented accuracy (±1 to 3 my) can be achieved for virtually all 2700 my old zircon populations from plutonic or volcanic rocks The procedures work even better for younger zircons Besides removing outer layers that may have been leached, high-U parts are preferentially removed by abrasion because they are softened by radiation damage Altered and cracked zircons also tend to be eliminated In most cases, the new concordant data move up the line established by previously analysed paramagnetic fractions but a number of anomalies have been found where old data give upper intersections that are in error by as much as 25 my Reducing or eliminating paramagnetically correlated Pb loss greatly enhances our ability to define mixing lines for igneous or metamorphic rocks when two ages of zircon are present The abrasion technique allows detection of an inherited component if it exists by enhancing the sample in core material Abrasion in many cases removes about 80 percent of the common lead, thus allowing a direct evaluation of this component When the outer parts of grains are removed, the correlation between magnetic susceptibility and uranium content is maintained but the usual correlation of uranium level with lead loss is reduced or eliminated Therefore, only near surface uranium is involved in the classic discordance versus uranium level correlation of Silver (1963)

Robust self-cleaning surfaces that function when exposed to either air or oil

Abstract: Superhydrophobic self-cleaning surfaces are based on the surface micro/nanomorphologies; however, such surfaces are mechanically weak and stop functioning when exposed to oil. We have created an ethanolic suspension of perfluorosilane-coated titanium dioxide nanoparticles that forms a paint that can be sprayed, dipped, or extruded onto both hard and soft materials to create a self-cleaning surface that functions even upon emersion in oil. Commercial adhesives were used to bond the paint to various substrates and promote robustness. These surfaces maintained their water repellency after finger-wipe, knife-scratch, and even 40 abrasion cycles with sandpaper. The formulations developed can be used on clothes, paper, glass, and steel for a myriad of self-cleaning applications.

Effect of surface conditioning methods on the bond strength of luting cement to ceramics

Abstract: Objectives. This study evaluated the effect of three different surface conditioning methods on the bond strength of a Bis-GMA based luting cement to six commercial dental ceramics. Methods. Six disc shaped ceramic specimens (glass ceramics, glass infiltrated alumina, glass infiltrated zirconium dioxide reinforced alumina) were used for each test group yielding a total number of 216 specimens. The specimens in each group were randomly assigned to one of the each following treatment conditions: (1) hydrofluoric acid etching, (2) airborne particle abrasion, (3) tribochemical silica coating. The resin composite luting cement was bonded to the conditioned and silanized ceramics using polyethylene molds. All specimens were tested at dry and thermocycled (6.000, 5 – 55 8C, 30 s) conditions. The shear bond strength of luting cement to ceramics was measured in a universal testing machine (1 mm/min). Results. In dry conditions, acid etched glass ceramics exhibited significantly higher results (26.4– 29.4 MPa) than those of glass infiltrated alumina ceramics (5.3– 18.1 MPa) or zirconium dioxide (8.1 MPa) (ANOVA, P , 0:001). Silica coating with silanization increased the bond strength significantly for high-alumina ceramics (8.5– 21.8 MPa) and glass infiltrated zirconium dioxide ceramic (17.4 MPa) compared to that of airborne particle abrasion (ANOVA, P , 0:001). Thermocycling decreased the bond strengths significantly after all of the conditioning methods tested. Significance. Bond strengths of the luting cement tested on the dental ceramics following surface conditioning methods varied in accordance with the ceramic types. Hydrofluoric acid gel was effective mostly on the ceramics having glassy matrix in their structures. Roughening the ceramic surfaces with air particle abrasion provided higher bond strengths for high-alumina ceramics and the values increased more significantly after silica coating/silanization. 2003 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Fluoroalkyl silane modified silicone rubber/nanoparticle composite: a super durable, robust superhydrophobic fabric coating.

Abstract: A superhydrophobic fabric coating made of a crosslinked polydimethylsiloxane elastomer, containing well-dispersed hydrophobic silica nanoparticles and fluorinated alkyl silane, shows remarkable durability against repeated machine washes, severe abrasion, strong acid or base, boiling water or beverages and excellent stain resistance.

Use of tire rubber particles as addition to cement paste

Abstract: The surface modification of powdered tire rubber to increase its adhesion to cement paste was studied. The particles were surface-treated with NaOH saturated aqueous solutions for 20 min. Scanning electron microscopy (S.E.M.), water absorption, density, flexural strength, compressive strength, abrasion resistance, modulus of elasticity and fracture energy measurements were performed using test specimens (water/cement ratio=0.36) containing 10% of as-received or 10% of NaOH-treated rubber. The results of fracture energy and flexural and compressive strength show that the addition of rubber particles improves the toughness and reduces the porosity of the specimens. Mass loss by abrasion (−1.2±0.4% for control specimens; −1.7±0.4%, using treated rubber and −4.0±1.2% using as-received rubber, after 600 cycles) and electron microscopic examination show that the NaOH surface treatment enhances the rubber–matrix adhesion. The use of thus treated tire rubber particles, as addition, instead of a coarse aggregate, in cement-based materials is promising for applications such as driveways or in road construction.