This paper aims at exploiting the accurate precise measurements of CMM machine in exploring and investigating the wear happening between contacting solid surfaces. For instance, excessive wear, if detected by the CMM measurements, in a cylinder bore of an internal combustion engine can dramatically affect its performance quality, sealing function, scheme of lubrication, and eventually its service life span. In such case, the finger print would be the original design GD&T tolerances. Widely spread availability of CMM machines at a reasonable cost may make the applicability of this novel technique of wear detection feasible. In this work, precise and accurate measurements of deviations in roundness, straightness, and concentricity in a cylinder bore of an air cooled Automotive Diesel Engine dismantled for an overhaul using a CMM machine have been executed and analyzed to validate this technique. Thus, the results have been presented, discussed, analyzed and interpreted in order to evaluate the status of the engine during operation. Locations of remarkable deviations representing aggressive wear happenings in the cylinder bore are detected and investigated. The measurements, within the limits of uncertainty attributes, could reflect the performance quality of the engine, the suitability of the applied scheduled maintenance plan, and may also point at possible adverse operating conditions contributed to this wear. In the light of the findings, recommendations may thus be drawn and offered to the engine designer to improve his design. For instance, surface treatments and coatings could be preferably changed, or an innovative constructional modification may be suggested to homogenize the wear occurrence in the cylinder bore during operation. This may extend the operating life span of the cylinder and in turn reduces the maintenance expenses. This novel technique for the wear development recalling proved to be successful and reliable tool to diagnose the root causes of the wear aggression occurrence.

No abstract

Concrete is one of the main materials in the construction industry. The Ordinary Portland Cement (OPC) concrete is vastly used as the main binder in construction industry which leads to depletion of natural resources in order to manufacture large quantities of OPC. Environmental hazards result from OPC production have become a major concern today. Nevertheless, Geopolymer concrete production (GC) is a new environment friendly construction material, due to less emission of carbon dioxide. An experimental study on some engineering properties of Geopolymer Mortar (GM) prepared using the fly ash (FA) and rice straw ash (RSA) is presented in this research. FA was replaced with RSA by 0, 5, 10, 15, 20, and 25% where the sodium silicate and sodium hydroxide were used as alkaline activator. The casted GM was divided in two main groups to study the effect of curing temperature. The first group was cured at room temperature for 28 days. The second group was cured at 80ºC for 24 hours in an oven curing tank then in room temperature for 27 days. The test results show that compression strength and flexural strength of geopolymer mortar increase when the percentage of RSA increases up to 5% replacement. The geopolymer materials exhibited strength increases after temperature exposure for 28 day.

In this study the effects of temperature, fermentation type and hydraulic retention time were investigated to optimize biogas yield and minimize production costs under lab scale for batch anaerobic digestion of goat manure. The growth and activity of anaerobic microorganisms is influenced by some parameters like temperature, moisture content, pHvalue and volatile fatty acids (VFA), which were measured before the study. The methane values were between (61.89 -69.35%). A cost equation was determined to calculate the total biogas cost LE/liter at different conditions. The minimum biogas production cost was 4.09 LE/liter at the highest cumulative production of 128.74 liter at temperature of 60 °C for dry fermentation.

No abstract