The aim of this study was to determine whether there was any difference in the degree of enamel loss at bond-up, debond and enamel clean-up when two different adhesive systems were tested and with four different methods of enamel clean-up. The adhesive systems were 37 per cent o-phosphoric acid with Transbond XT (group 1) and 10 per cent poly(acrylic acid) conditioner with Fuji Ortho LC (group ...

OBJECTIVE To study exposure to cobalt and chromium in saw maintenance rooms and test respiratory health among saw filers at lumber mills. Hard-metal lung disease is associated with cobalt in the manufacture of tungsten carbide tools; recently it has also been reported among tool maintenance workers. Lumber mills often use saws tipped with tungsten carbide or with a newer alloy, stellite (contai...

surface roughness is one of the most important parameters that plays very critical role in determining the quality of engineering components. a good surface quality resulting in improve of fatigue strength, corrosion and wear resistance of the workpiece. on the other hand, increasing cutting speed and decreasing time of machining are desirable for manufacturers in order to reduce costs and incr...

Carbide tungsten cobalt alloys were deformed in compression or in three point bending in a temperature range 1000-1350°C and in a stress domain 30-1000MPa. In these conditions, the stress exponent n of WC-CO alloys is a function of only the cobalt volurnic ratio and tends tow rds n = 1 for pure B carbide. The apparent activation energy is 550 kj mole. T.E.M. investigations on pure carbide defor...

this study aimed to evaluate enamel roughness after adhesive removal using different burs and an er:yag laser.the buccal surfaces of forty human premolars were sealed by two layers of nail varnish, except for a circular area of 3 mm in diameter on the middle third. the enamel surfaces were initially subjected to profilometry analysis and four parameters of surface irregularity (ra, rq, rt and r...

Tungsten carbide exhibits platinum-like behavior, which makes it an interesting potential substitute for noble metals in catalytic applications. Tungsten carbide nanocrystals (≈5 nm) are directly synthesized through the reaction of tungsten precursors with mesoporous graphitic C(3)N(4) (mpg-C(3)N(4)) as the reactive template in a flow of inert gas at high temperatures. Systematic experiments th...

driver (Figure 1), is made from stainless steel and is used to hold a suturing needle during surgical procedures. To maintain a firm grip on the needle, the jaws have textured patterns either etched directly on the stainless steel or on a replaceable tungsten carbide insert, which grips the suture needle more precisely and wears out much slower than stainless steel. Needle holders with tungsten...

The Report on Carcinogens includes two separate listings (i.e., profiles) for cobalt-related exposures: Cobalt and Cobalt Compounds That Release Cobalt Ions In Vivo and Cobalt-Tungsten Carbide: Powders and Hard Metals. Cobalt and cobalt compounds as a class are listed for the first time in the Fourteenth Report on Carcinogens, and this listing includes and supersedes the listing for cobalt sulf...

in the testicular damage caused by indium arsenide and indium phosphide in hamsters during two years after intratracheal instillations. (CIGS) nanocrystal " inks " for printable photovoltaics. Selective sequential dissolution for the determination of inorganic indium compounds in the particulate matter of emissions and workplace air. Current evaluation Conclusion from the previous Monograph (IA...

Tungsten carbide nanocrystal modified Pt catalysts have been prepared by an intermittent microwave heating (IMH) method and show an improved activity for oxygen electroreduction in alkaline media.