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A. Venugopal, Amit Agrawal, S.V. Prabhu
FLOW VISUALIZATION STUDIES ON TRAPEZOIDAL BLUFF BODY FOR VORTEX FLOWMETER APPICATION

In the present study, turbulent flow visualization is carried out to understand the vortex formation mechanism behind a trapezoidal bluff body, for vortex flowmeter application. The dye used for flow visualization is shear-thickening and high extension viscosity fluid, which can sustain turbulent separated flows. With the quantitative assessment of the images, the vortex frequency is computed which is in close match with the results obtained from Piezo-electric sensor based measurement. The study enhances the understanding of the complex vortex formation mechanism in the design of vortex flowmeter.

M. Zucco, M. Bisi, P. Cordiale
THE REALIZATION OF THE DEFINITION OF THE METRE AT INRIM

In this paper we present the traceability chain for the calibration of the frequency of laser standards that realize the definition of the metre at the National Institute of Metrological Research (INRIM) in Italy in accordance with the mise en pratique issued by the CIPM. We describe the way our femtosecond laser frequency combs are referenced to the SI second and the new research activity on the production and testing of iodine cells.

A. Miklavec, I. Pušnik, V. Batagelj, J. Drnovšek
BLACKBODY AND PROCEDURE FOR CALIBRATION OF THERMAL IMAGERS

The article describes the bath with a large aperture blackbody, purposely designed and constructed for calibration of thermal imagers. For interpretation of experimental results and also for determination of inner blackbody temperature a numerical model was build. Based on available equipment a calibration procedure for thermal imagers was developed with special emphasis on evaluation of entire imager FOV.

A. Piratelli-Filho, F. H. T. Fernandes, R. V. Arencíbia
INTERLABORATORY COMPARISON OF ARTICULATED ARM CMMS USING VIRTUAL SPHERES PLATE GAUGE

This work presents an approach to perform interlaboratory comparison of Articulated Arm Coordinate Measuring Machines (AACMM) with Virtual Spheres Plate (VSP) gauge. This gauge has a determined number of pyramidal inserts having four conic holes each. These inserts were designed to fit virtual spheres with coordinates of the four points determined by measurement. The gauge has to be delivered to the laboratories under evaluation and the diameter and the center-to-center distances among the virtual spheres must be determined to apply normalized error analysis. The results proved suitable to evaluate the machine errors and to compare these machines.

Mirela Adelaida Anghel, Fãnel Iacobescu
QUALITY ASSURANCE OF BREATH ALCOHOL MEASUREMENTS

Romania, as a member state of European Union, started to develop together with its National Institute of Metrology, efficient measures to detect drivers under influence with accurate results and to assure the traceability of mass concentration of alcohol in exhaled breath. The paper describes the complete system used for testing of ethylometers performance and the method applied to prepare and certify the standard solutions. The expanded uncertainty for the complete simulator system was calculated taking into consideration all input quantities which have noticeable contribution to the final uncertainty.

José Carlos Valente de Oliveira
TAKING RIGHT FINAL CONCLUSIONS AND DECISIONS WITH THE USE OF THE MOST APPROPRIATE KEY COMPARISON REFERENCE VALUE (KCRV)

The best way that a National Metrology Institute (NMI) has to demonstrate confidence in its measurement results and, consequently, in its measurement capabilities is the the participation in key comparisons. Usually, it is not so obvious to choose the key comparison reference value (KCRV). The main purpose of this paper is to present the considerations done about the measurement results contained in some final reports of some different key comparisons, chosen as case studies, aiming to establish the KCRV.

V. A. Granovskiy, T. N. Siraya
METROLOGICAL CHARACTERISTICS OF MEASURING INSTRUMENTS: PROBLEMS AND METHODS OF STANDARDIZATION

The paper considers standardization problems and methods that are concerned with metrological characteristics of measuring instruments in the context of the system approach. The main aims and principles of standardizing and estimating metrological characteristics are presented. General objectives and possible methods of standardization are discussed. Related concepts of pattern and norm are analyzed. Proposals on improving standardization methods for various groups of measuring instruments are elaborated.

J. J. L. Sousa, L. T. S. Leitão, M. M. Costa, M. C. Faria
CONSIDERATIONS ON THE INFLUENCE OF TRAVELLING STANDARDS INSTABILITY IN AN INTERLABORATORY COMPARISON PROGRAM

This paper has the purpose to show how the instability of travelling standards can affect the results of an interlaboratory comparison program, and how to evaluate its influence in the determination of these results, in order to not compromise the assessing of a laboratory when En value is used for this purpose. In this work are presented and discussed five options of instability compensation of the travelling standard.

Martin Motycka, Olga Tumová
INFLUENCE OF MEASUREMENT ACCURACY ON THE RELIABILITY OF REGRESSION MODEL ESTIMATION FOR D-OPTIMAL PLANS EVALUATION

The main objective of this paper is to describe the dependence of the reliability of estimates of the regression model due to measurement accuracy. The main focus is on the experiments with reduced number of the tests, especially on the D-optimal plans, because these types of experiments are nowadays very important in the industrial praxis.

M. Lauri, R. Ritala
RECEDING HORIZON CONTROL FOR SELECTION OF FOCUS OF ATTENTION

We consider the problem how a mobile robot equipped with a sensory subsystem with multiple operation modes should focus its attention to provide optimal support for finding the shortest path to a given target. The path planning problem is considered as a search task in a directed graph. The path planning is linked to the focus of attention problem by noting that any observations made of the environment ultimately reveal us information on the arc weights in the graph, i.e. the cost function. The formulation allows us to describe consistently various phenomena affecting optimal paths in the environment, for example moving obstacles that the robot may not collide with. We give a formulation for a cost function that allows trade-off between exploration of the environment and exploitation of current information by a scaling parameter.

Page 678 of 977 Results 6771 - 6780 of 9762