Leo Van Biesen, Tamás Kemény, Dirk Röske
NON-GOVERNMENTAL COOPERATION IN MEASUREMENT

IMEKO is a non-governmental federation of 35 national Member Organisations, individually concerned with the advancement of measurement technology and instrument engineering. The Member Organisations are scientific/technical societies or committees. The membership consists of the representatives of metrological institutions, higher education, industry and the users of instruments. The paper deals with the objectives of the Confederation, informs on the structure and financial background, on IMEKO imeko_proceedings and on the activities of 20 Technical Committees. Finally the future World Congresses, different scientific services, membership development, events and co-sponsorships are discussed.

Diana Milcic, Dubravko Banic, Davor Donevski
The effective vibration speed of web offset press

The purpose of this study was to investigate the existing maintenance models of web offset presses, and to propose the method which increases the reliability of the printing press exploitation, but does not require big investments. Doctor motors allowed constant monitoring by measuring instruments, which allowed insight in current status of motors at any time, so they could be repaired or replaced before malfunction. The effective vibration speed (v_RMS) was measured a few times during the year 2006. Standard ISO 2372-1974 (E) defines values and boundaries of the effective vibration speed (v_RMS). Results of measuring effective vibration speed indicated the emersion of nuisance energy with deterioration. To determine the state of bearings, and check if they cause the increase of effective vibration speed, an envelope analysis - FFT of the acceleration specter is conducted. This decreases the probability of motor malfunction and greatly increases the reliability of the whole system.

Praxedis I. Santamaría M., Román Tejeda C
Activities designed to establish relationships between concepts as a didactic strategy in the metrology teaching process

The teaching of metrology in undergraduate courses includes concepts such as traceability, calibration and uncertainty. This paper proposes a certain activity that students will have to realize in the Metrology Laboratory. The purpose of this activity is that students understand the contribution that the traceability chain has in the estimation of the uncertainty of a measurement. The activity should be realized in three stages. The first one consists of the construction of a mass measuring device. In the second stage, the pupil realizes the calibration of the device with two different patron mass kits. In the third stage, the student weighs different problem masses and informs the value of the measurand with an uncertainty statement, calculated with the information of his previous calibrations. Once the student has obtained different uncertainties of the same measurand, estimated with the same instrument, the instruments’ traceability relevance will be set.

Matej Grum, Martin Terlep
Analysis of Change of Mass Difference between Weight Support Plates during Subdivision of 1 kg

In the research a possibility was studied how to reduce a number of repetitions of measurements when performing dissemination of 1 kg mass standard and at the same time maintain the level of confidence of the measurement results.
The method considered is designed for weighing schemes where a pair of support plates for weights is required to carry out comparisons of combinations of weights on comparators with automatic weight handler and the same pair of support plates is used for many of the compared weight combinations.
The results of analysis indicate to minor relation between the changes in mass differences of the compared weights and the changes in mass differences of the support plates. It can be seen that there is no influence on the mass of compared weights due to improper handling of the weights. The main reason for the deviations of the measurement results when using the support plates might be the performance of the comparator.

Hideaki Nozato, Takashi Usuda, Akihiro Oota, Tamio Ishigami and Katsuhisa Kudo
Development of Shock Acceleration Calibration Machine in NMIJ

Calibrations of shock acceleration are industrially required from a view of human safety and product development. In NMIJ vibration group, a shock acceleration calibration machine (hereafter ‘calibration machine’) has been developed in response to much demand from Japanese industries, and can calibrate shock transducers in acceleration range from 200 m/s² to 5000 m/s². For primary calibration, accelerometer is calibrated by a combination of shock exciter and laser interferometer. In the shock exciter, shock acceleration is generated by rigid body collision between a hammer and an anvil. To avoid any disturbance motion, radial air bearing system is adapted to keep high stiffness in perpendicular directions to the collision. The hammer, supported by the air bearing, is accelerated by an air gun and collides with the anvil through a rubber pad. Thus, acceleration waveform of the anvil strongly depends on viscoelasticity of the rubber pad. Different hardness of the rubber pad is examined to realize various peak accelerations. As another significant issue, optimization of low-pass digital filter is necessary to obtain reliable acceleration waveforms. This manuscript reports not only a procedure of low-pass digital filtering but also cut-off frequency dependence of low-pass digital filter on peak acceleration.