W. Sabuga, T. Priruenrom
To improve the consistency of 3-dimensional data describing the geometry of pressure-measuring piston-cylinder assemblies, a new approach, based on the leastsquares method, is proposed. It allows the results of diameter-, straightness- and roundness measurements to be linked with each other, with only minimum discrepancies between them. When processing the dimensional data, it is possible thanks to this new approach to weight them differently - according to their measurement uncertainties. The new approach was applied to three gas-operated piston-cylinder assemblies with nominal effective...
Cultivating Metrological Knowledge
· TC16
· 2007
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Hiroaki KAJIKAWA, Tokihiko KOBATA, Kazunori IDE, Akira OOIWA
We are now developing a new controlled-clearance pressure balance to upgrade the hydraulic high-pressure standard up to 1 GPa. Characterization experiments for a 500 MPa controlled-clearance piston-cylinder were performed in detail over wide pressure range, and the effective area was estimated based on the Heydemann-Welch model. The estimation based on the conventional model agrees well with the present pressure standard. However, at high pressures around 500MPa, there appears some contradictions to the assumption of the model; especially, the jacket pressure coefficient depends apparently...
Cultivating Metrological Knowledge
· TC16
· 2007
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Pedro Silva Girão, Octavian Postolache, José Miguel Dias Pereira
This article is about a special type of pressure sensors usually labelled tactile sensors. After a short overview on the subject, two application examples, one in the medical domain developed by the authors for heart rate variability using an electretsbased pressure sensor, are presented.
Cultivating Metrological Knowledge
· TC16
· 2007
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A. Nunes, M. Piedade1, R. Neves
This paper proposes the architecture of a pressure sensing floor divided in rigid tiles. The system is based on a network of flexible pad pressure sensors, used under all tile corners, connected to special local data acquisition circuits. Signals captured by the sensor units are transmitted to a system controller that process, display and store the information received. The proposed architecture was applied in an interactive room with a 64 tiles floor, providing a network weight measuring system that allows detecting, recording and tracking the movement of objects or people over the...
Cultivating Metrological Knowledge
· TC16
· 2007
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Sari Semenoja, Martti Heinonen
Devices measuring pressure, temperature and humidity simultaneously are known as PTU devices. There are hardly any commercial calibration systems for the PTU devices available for low temperatures (< 0 °C). To obtain more comprehensive data on the performance of PTU devices, a new calibration system is developed at MIKES. In this PTU Apparatus, pressure, temperature and humidity can be controlled simultaneously so that all combinations over the ranges are possible. The nominal ranges of the system are the following: absolute pressure 500 hPa … 1200 hPa, temperature -52 °C … +80 °C and...
Cultivating Metrological Knowledge
· TC16
· 2007
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Luis O. Becerra
Within the frame of SIM (Sistema Interamericano de Metrología) some inter laboratory mass comparisons have been performed in different nominal values. The main objective of those comparisons was to evaluate the degree of equivalence of SIM National Metrology Institutes (NMIs) between themselves and between SIM’s NMIs with NMIs from other metrological regions. This paper presents the degree of equivalence in 1 kg between SIM’s NMIs and between SIM’s NMIs with the Key Comparison Reference Value (KCRV) of CCM.M-K1.
Cultivating Metrological Knowledge
· TC3
· 2007
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Luis M. Peña, J. Carlos Pedraza
The present work illustrates the improvements made to the hydrometer calibration sys-tem of CENAM, the NMI of Mexico, making use of an image processing technique to align the scale mark of the hydrometer to the surface of the liquid where it is immersed, reducing the variability in the apparent mass determination during the hydrostatic weighing in the calibration process, decreasing the relative uncertainty of calibration ( k = 2) from 1 x 10 -4 to 5 x 10 -5 or better.
Cultivating Metrological Knowledge
· TC3
· 2007
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Christian Buchner
In cooperation with Sartorius AG in Goettingen and the Vienna University of Technology, the Austrian Federal Office of Metrology and Surveying (BEV) has developed a test System for hydrostatic weighing and determining the density of liquids and solids, whereby mass comparators are automatically loaded alternately with weights and submerged plummets. With the load alternator for weights and plummets, the density of a liquid on one side and the density of a submerged solid (and therefore its volume) on the other side can be determined hydrostatically via direct comparison with Standard...
Cultivating Metrological Knowledge
· TC3
· 2007
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S. Lorefice, A. Malengo, M. Caravaggio, L. Cianciotta
The design and the expected performance of a new apparatus suitable to satisfy the traceability requirements in the density field is here presented. The apparatus is mainly intended to measure liquid density range between 500 kg/m³ and 3000 kg/m³ and to evaluate the performance of on-line densimeters during the actual use, i.e. the same process liquid under similar flow conditions. Details about the hardware components of the system and the software programs are also given. By using an instrument not specifically selected and calibrated for the intended working conditions, the value of u...
Cultivating Metrological Knowledge
· TC3
· 2007
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Luis O. Becerra, Dalni Malta, Luz. Ma. Centeno, José Julio Pinheiro
This paper presents the results obtained for a SIM comparison between CENAMMexico and INMETRO-Brazil in volume of solids by hydrostatic weighing measurements. In this work are presented a scheme of measurements, and the systems used by the National Metrology Institutes. The travelling standards were two spheres made of different materials (stainless steel and glass) with approximated diameter of 15 mm each.
Cultivating Metrological Knowledge
· TC3
· 2007
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