Sand dust can enter into an engine lubrication system through the intake manifold. The effect of calcite and silica sand dust particles in an engine on oil particle contamination was investigated. The presence, amount, and size of silica and calcite particles in engine oil were determined using X-ray diffraction (XRD), inductively coupled plasma (ICP) spectroscopy, and energy dispersive X-ray spectroscopy (EDX). Four levels of silica and calcite particles were obtained through engine oil sampling from farm tractors at the east of Isfahan (Iran) then, used to investigate their effect on the wear of engine moving parts after 20 hours of engine operation. The ICP analysis showed the amount of iron, aluminum, chromium, copper, nickel, and lead increased in the engine oil with increasing silica content, whereas aluminum and copper increased as the calcite content increased. In zero, 1, 2, and 3 g/L of the silica content of the engine oil, there were 6.2, 136.7, 176.3, and 1758.6 mg/L of iron particles, 0.18, 27.38, 46.65 and 47.85 mg/L of aluminum particles, and 0, 3.54, 5.85, and 10.73 mg/L of chromium particles, respectively. Thus, the quality of filters in agricultural tractors is to be improved to prevent engine wear by sand dust.

Surface curvature affects adhesion forces, deformations of surfaces in contact, leakage of mechanical seals, friction, wear, paintability, and electrical conductivity. However, potential benefits of surface curvature have not yet been fully utilized. One problem is the lack of comparison data helping to make an informed decision on the selection of curvature characterization method. In this paper, five multiscale curvature characterization methods, namely Nowicki, Bigerelle-Nowicki, Gleason-Heron, Kalin, and Bartkowiak are compared. The comparison was conducted on large image databases of computer-generated fractal surfaces, sine waves and real engineering surfaces. Specifically, the methods were evaluated for their ability to differentiate between surfaces that: (i) exhibit increasing curvature complexity, (ii) have varying curvatures at a single scale, and (iii) represent minute multiscale curvature changes encountered in real engineering applications. The results obtained indicate that the Bigerelle-Nowicki method exhibits the best overall performance.