This paper reports work carried out to determine the influence of the Pyramidal indenter geometrical errors and tolerances on the accuracy of Vickers hardness measurements. The angle between the opposite faces and line of conjunction of nine indenters were measured by the optical comparator. The influence of the indenter geometry on the hardness accuracy is investigated. Three calibrated reference hardness test blocks were used to check the Vickers hardness test using the nine selected indenters. The results show that the geometrical error of the indenters (specially the angles) considerably affects the accuracy of the hardness measurement. Finite element analysis of the indentation process into metallic test pieces was conducted. Comparison of the experimental results with the numerical findings was discussed. Errors in the experimental values are correlated with measured tolerances in the angles between faces.

We describe an efficient continuous-wave diode-pumped Nd:YLiF4 laser oscillating on the σ-polarized 4F3/2-4I13/2 transition at λω = 1312 nm. With a simple linear cavity laser, we reached an intracavity power of 310 W at λ = 1312 nm for 16 W of absorbed pump power (λp ~ 806 nm). A 0.25 W of tunable radiation (λ2ω = 656−658 nm) was obtained by intracavity second-harmonic generation (SHG) with a 5 × 5 × 7 mm3β-BaB2O4 crystal. Up to 10 mW of tunable single-frequency operation was observed using a 200 μm thin fused silica intracavity solid etalon. The optimal waist for a maximum conversion efficiency has been calculated theoretically using Boyd and Kleiman model. For the 1312–656 nm SHG, we found a walk-off parameter B = 8.99 and an optimal waist of 25 μm. Comparing to the experimental measurement of the optimal waist, we found a relative discrepancy of 2.84 × 10-2. This laser is dedicated to the spectroscopic study of silver atoms trapped in a buffer-gas-free paraffin coated Pyrex cell that will be used in a compact atomic optical clock.

Today’s global economy obliges manufacturers to produce their products in high quality with cheaper cost. Thus, manufacturers must develop their products applying tests to get better performance and higher quality before distributing them to the competitive market. In order to produce long working life of transformer reactors without losing their performance, different tests including axial and flexural testing are applied on the cellulose based laminated board material used in production. During development of laminated board material, test results should be known very well and the measurement uncertainty of tensile tests should be calculated taking into account all parameters. In this study, effective parameters on the quality of tensile testing causing an increase on the measurement uncertainty are investigated. Tensile strength and elongation test of laminated board material were carried out according to IEC 60641-2 and the uncertainty contributions based on experimental results were calculated. The results and impact of the uncertainty parameters are presented in detail.

This paper presents the evaluation of the uncertainty for the length measurement of gauge blocks by optical interferometry. In order to improve the gauge block calibration method and to decrease measurement uncertainty the old Zeiss-Kösters gauge block interferometer has been modified and improved by DMDM (Directorate of Measures and Precious Metals of Serbia). The main modification of the interferometer covers introduction of two laser sources, as new wavelength standards, as well as new hardware system and interferometer software, developed to completely automate the calibration process. The validation of the new measurement procedure details the uncertainty budget. The measurement method and model equation, which serves as the basis for the uncertainty evaluation is described. The uncertainty evaluation is performed in accordance with the document JCGM 100:2008-Evaluation of measurement data – Guide to the expression of uncertainty in measurement (GUM).

A number of calibration techniques are used in Radio Frequency (RF) calibration for power, attenuation and impedance parameters. Mismatch uncertainty plays a major role in these measurements and in estimation of combined uncertainty according to ISO/IEC 17025:2005 and GUM document. Formulas to evaluate the mismatch uncertainty in terms of reflection coefficient, voltage standing wave ratio and scattering parameters have been evaluated earlier and are being used in RF calibration. The present paper summarizes the mismatch formulas previously studied and the modified ones suitable to the measurement system and techniques available today. For power and attenuation calibration in the particular frequency range, an establishment of traceability for one-port measurement in the same frequency range is required. The methods to reduce and control this uncertainty component and their limitations are also discussed forbest measurements practices in the calibration laboratories.

Quality of transformer oil plays vital role in the performance of transformer in electrical appliances. Measurement uncertainty is a general concept associated with any measurement and can be used in professional decision processes as well as judging attributes in many domains, both theoretical and experimental. As the tolerances applied in industrial production become more demanding, the role of measurement uncertainty becomes more important when assessing conformity to these tolerances. Measurement uncertainty plays a central role in quality assessment and quality standards. In an effort to meet national, international and commercial accreditation requirements, users of transformer oil testing machines must establish adequate methods of determining calibration and test measurement uncertainties. Determining measurement uncertainty for transformer oil testing equipments and test data can be a very complex process. Many factors affect the uncertainty of test data produced by testing machines. In this paper, the concepts associated with the procedure for estimation of uncertainty is discussed and the application of these for the determination of uncertainty in transformer oil testing equipments in government testing labs is illustrated. The objective of this study is to develop a methodology for determining the result of measurement concerning electrical properties of transformer oil and their respective uncertainties.

Three dimensional coordinate metrology is a firmly established technique in industry. Scanning technology is now widely used in coordinate metrology and is increasingly used for the measurement of small features. This paper presents a new real shape approach to closest point inspection involutes curve of gear tooth by coordinate measuring machinery (CMM). This method aims to select the most likely contact point for each successive arc by applying geometrical criteria and a fuzzy logic estimator. This method is particularly, but not exclusively, suitable for the metrology of features with small radii as well as metrological discontinuities. It does not require obtaining the normal vector traditionally used for probe tip correction. Elapsed time is 144.09 s. Tests have been done on limps of machine tool speed (pinion type cutter), which is highly applied in our country.

This research work describes a novel approach for comparing different technologies for free form surface metrology: computerized tomography (CT), photogrammetry and coordinate measuring machines (CMM). The comparison has the aim of providing relevant information for the selection of metrology equipment when measuring free form components. Results demonstrate that there is the imperative need to assess the uncertainty and reproducibility of CT and photogrammetry measurements by applying some calibration procedures taking into account some recommendations for work piece alignment. This article also deals with costs issues, required standards, and necessary additional information when selecting inspection equipment.