Using Iraqi materials to produce lining refractories with international standards
In this study dense high alumina refractories were manufactured according to DIN51053 standards and characterizations (physical, mechanical, and thermal) of fired specimens were investigated. The mixtures of specimens were prepared from different weight percentages of (kaolinite, bauxite with additives of alumina to all mixture ratio). The aims of this study was to benefit of local raw materials to produced high alumina refractory characterized by low porosity, in addition to manufacture thermal insulation to use as lining in different industrial furnaces, and enhance the thermal insulation, thermal stability, and mechanical properties of high alumina refractory by adding alumina. From the results it have been obtained high alumina refractory with high compressive strength, high thermal stability, and thermal insulation also have characterized by low porosities and high bulk density.
Silica-Alumina Refractory Synthesis based on Moroccan Granitic Geo-Materials
Andalusite rich schist until now has not been utilized to produce refractory. In this work, refractory materials were elaborated from alumina-silica geomaterials related to granitoids and their direct surrounding rocks (kaolin clay and andalusite riche schist). Characterization evolution on heating was investigated in a composition (80% kaolinitic clay, 20% andalusite rich schist). The evolution of mullite was examined by SEM (scanning electron microscopy) and XRD (X-ray diffraction). The thermal shock test showed that the refractory sample has a good thermal shock resistance.
Traceability strategy for gear-pitch-measuring instruments: development and calibration of a multiball artifact
There is a strong demand to ensure the traceability of gear-measuring instruments (GMIs). We propose a multiball artifact (MBA) for the evaluation of pitch-measuring accuracy. The aim of the MBA is to transfer the minimum uncertainty from a calibrated value at the National Metrology Institute of Japan (NMIJ) to a measured value of GMIs at a shop floor. The MBA is composed of equally spaced high-accuracy balls around an axis. The pitch-measuring accuracy of GMIs is evaluated by measuring the angular pitch deviation of the balls instead of the angular pitch deviation of a gear. We calibrated the angular pitch deviation using a coordinate measuring instrument (CMM) at the NMIJ and adapting a multiple-orientation technique. We proposed a calibration strategy of the angular pitch deviation. The calibration value of the pitch deviation for the MBA at the NMIJ was obtained with a measurement uncertainty (U95) of 0.2 µm. We evaluated the pitch-measuring accuracy of a GMI using the calibrated MBA. Each value of U95 for the cumulative and single pitch deviations for the left and right flanks was less than or equal to 0.5 µm. The small uncertainty was transferred from the NMIJ to the GMI.