OBJECTIVE Toothbrush abrasion is significant in the development of tooth wear, particularly when combined with erosion. This in vitro study aimed to evaluate the impact of toothpaste slurry abrasivity and toothbrush filament stiffness on abrasion of eroded enamel. MATERIAL AND METHODS Eroded enamel samples (hydrochloric acid, pH: 2.6, 15 s) were brushed with 40 strokes in an automatic brushin...

Polycrystalline diamond compact (PDC) bits have been widely used in oil and gas well drilling recently also begun to be geothermal drilling. In the present study, performance wear of a PDC bit were assessed by laboratory tests. The correlation between progress some indexes rock abrasivity was discussed referring test results. rate penetration formulated as function weight on using results for o...

pits, quarries, and on construction sites. The prediction of the penetration rate of drilling machines is very important for cost estimation and planning of rock excavation projects. Many researchers have investigated percussive drilling theoretically or experimentally and correlated the penetration rate with various rock properties. Protodyakonov (1962) developed drop tests and described the c...

The Chamshir water conveyance tunnel (CWCT) with a length of 7.4 km and boring diameter of 5.3 m is excavated using a refurbished single shield TBM, initially designed to work in hard rock formations. This study focuses on engineering geological issues, which are important for checking the suitability of this machine and proposing required modifications for improving its performance in soft roc...

In the mining and civil engineering industries point-attack picks (conical picks) are extensively employed on mechanical excavators such as roadheaders, continuous miners and longwall shearers to cut relatively harder rocks/coals compared with radial picks. They are more durable than radial picks, and can economically cut intact rocks having up to around 120 MPa uniaxial compressive strength at...

Abstract In any underground excavation project, choosing the best technique and careful preliminary assessments of wear costs production rates are crucial aspects to consider. The rate tools, as well frequency tool replacement, deeply affect duration cost‐effectiveness whole project. Among rock‐specific characteristics affecting wear, Cerchar abrasivity index (CAI) uniaxial compressive strength...

Early dentifrices contained natural ingredients, mostly in coarse particle form, and were quite abrasive. Salts, either sodium chloride, sodium bicarbonate, or a mixture of both, have also been used for tooth cleaning because of their ready availability and low cost. Because of both their relatively low intrinsic hardness and their high solubility, another advantage is low abrasivity. Their big...

OBJECTIVE To evaluate, using conventional in vitro procedures, the abrasivity, enamel polishing properties, and stain removal effectiveness of various commercial dentifrices that have a variety of compositions and are marketed for cleaning, whitening, and/or polishing capabilities, and to examine their relationships between stain removal and abrasivity. METHODS The Relative Dentin Abrasivity ...