Analysis of archaeological samples and local clays using ICP-AES, TG-DTG and FTIR techniques.
The spectrochemical and thermal analysis of different archaeological samples as bricks, terra-cotta and local clays were carried out. The concentration of major and minor elements of samples was determined by sequential inductively coupled plasma atomic emission spectrometry. The method was tested by determining Si, Al, Fe, Ca, Mg, Mn, Pb, Cu, Zn, Ti, Na and K in the standard solutions and reference material GXR-4. The precision of the determination (relative standard deviation) ranged from 0.4 to 1.54%. The clay minerals are the main materials for the production of bricks and terra-cotta figures. Thermogravimetric (TG) and differential (TG-DTG) analysis and Fourier transform infrared spectrometry (FTIR) methods can be used for the study of characteristic reactions, associated with the course of the heating. The TG-DTG curves were obtained in the temperature range 25-900 degrees C, and the dynamic experiment was carried out in the air and nitrogen atmosphere. The infrared evolved gas analysis was performed using FTIR in the dynamic nitrogen atmosphere.
Rapid chelatometric determination of bismuth, titanium and aluminium using Semi-Xylenol Orange with visual end-point indication.
Abstract A rapid and simple general complexometric method was presented for the determination of bismuth, titanium and aluminium in laboratory synthesized alloys similar to those of some bauxites, clay, ilmenite, Portland cements and ceramic products. The precision and accuracy attainable in successive titrations of Bi3+, Ti4+ and Al3+ with 0.01 and/or 0.001M solutions of disodium ethylenediaminetetraacetate (Na2EDTA) and standard ZnCl2 of the same concentration, using Semi-Xylenol Orange (SXO) as a metallochromic indicator with visual end-point indication were studied. For one aliquot Bi3+ was at first directly titrated at pH 1–2 (HNO3) with Na2EDTA using SXO as indicator in the presence of L-ascorbic acid to reduce Fe3+ to Fe2+. At the bismuth end-point, an excess of Na2EDTA was added, the pH was adjusted with hexamine buffer (pH 5) and the excess of Na2EDTA was back-titrated with solution of standard zinc(II) chloride for both the simultaneous and consecutive titrations in the presence of (SXO) as indicator. For the simultaneous titration, fluoride was added to release the Na2EDTA combined with both Al3+ and Ti4+. For the consecutive titration, phosphate was added to release the Na2EDTA combined with Ti4+ and then fluoride to release the Na2EDTA combined with Al3+. The interference of various anions and cations in the determination of Bi3+, Ti4+ and Al3+ was studied. A comparison of the accuracy of both the simultaneous and consecutive titration was also carried out. The proposed methods were applied successfully to some real samples of bauxites, clay, ilmenite, Portland cements and ceramic products and the results were satisfactory.
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.