9762 papers found
The main purpose of this paper is to show how to reach a high precision in calibration of angle measuring devices for industry. Actually, the demand for use of optical polygons is growing, manly for calibration of CNC machines, and so their own calibration. The article will deal with basic concept and the actual technology, giving information and testing results as well as the evaluation of the uncertainty using “CIRCLE CLOSURE”.
The features of traceability structure of plane angle unit are considered. It is shown that the structure is contradicted the legalized unit, radian. It is offered to remove the contradiction by institution of the full angle (revolution) as the unit. The set of the problems demanding decisions for realization of this offer is outlined.
This paper deals with the traceability-assurance problems that are faced when a distributed measuring system is employed. These problems are highlighted for different distributed-system architecture, then a set of guidelines is provided in order to correctly manage such systems from a metrological point of view. The proposed solution is based on a network-assisted calibration procedure, which requires suitable travelling standards that are sent to the nodes of a distributed system under calibration and are remotely controlled through the Internet. Two prototypes of travelling standard are...
In this work it is presented the historical of the implementation and evolution of the metrology of the ionizing radiations in the Instituto de Radioproteção and Dosimetria, the formation of its technical staff, its participations in the Key-comparisons and in the metrological traceability programs developed by its metrology laboratory. It is also presented the main commitments assumed, as the adhesion to the Mutual Recognition Arrangement, MRA, the implementation and improvement of a quality system based on the ISO/IEC 17025, and the results of some quality indicators as the participations...
This work presents the experience of the National Laboratory for Ionizing Radiation Metrology (LNMRI) in the implementation of the requirements of the Mutual Recognition Arrangement (MRA) signed by 38 National Institutes of Metrology (NMI) in 1999. The degree of equivalence of activity reported by Bureau International des Poids et Mesures (BIPM) in the Key Comparison Data Base (KCDB), the main data of a specific radionuclide listed in the Calibration and Measurement Capabilities (CMC) and the implementation of a quality system are informed.
Rankings are sometimes considered to be non-empirical, non-objective, low-informative and, in principle, are not worthy to be titled measurement. In our opinion, a ranking is a result of measurement on ordinal scale and is useful to the same extent as any ordinal measurement.
Replication of measurements and the combination of observations are standard and essential practices in metrology. They are done with different methods to match distinct purposes.
Can we use the probabilistic interpretation of uncertainty budgets when analyzing measurement comparisons for consistency among the participants? Can statistical data analysis help simplify our understanding of comparison results, including the notions of a reference value, agreement, and for MRA KC only, ‘degrees of equivalence’ among the participants?
This paper presents a theoretic approach to measurement of the bottleneck times in production lines. The mathematical formalism utilized is characteristic for Discrete Event Systems approaches, and is about the Markov chains. Using this approach, we introduce definitions of bottlenecks, and we discuss their implications for production automation and preventative maintenance. The bottleneck of a production line is a machine that impedes the system performance in the strongest manner. The size of the buffer between the two machines is assumed to be finite. The approach is based on the...
In this work, a factorial design was applied for the development and validation of a solid surface roomtemperature phosphorimetric method aiming the selective determination of chrysene. Data analysis was made using several strategies: statistical experimental analysis (testing the significance of the factors using the analysis of variation, F -test and t -test), graphic method (Pareto´s chart) and the evaluation of the interactions among all variables. This procedure aimed the achievement of high accuracy of results and minimization of the time spent for optimization. A statistical program...