Jeerasak Pitakarnnop, Rugkanawan Wongpithayadisai, Suwat Phanakulwijit
An analytical and a numerical studies of rarefied gas effects on the flow through a vacuum pipe at low operating pressure are performed by the use of both continuum and kinetic approaches. The pipe operates in a high-Knudsen-, low-Reynolds numbers regime where the viscous effects dominate the flow. Since only the isothermal flow is focused, the slip-flow at the wall is the main anomaly. A comparison of the calculation results with those from the available measurements shows good agreement.
XXI IMEKO World Congress
· TC16
· 2015
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Stephen Downes, Andy Knott, Ian Robinson
In this paper we describe the work performed at the National Physical Laboratory (NPL) to develop dynamic pressure standards based on shock tube techniques, including the checks carried out to ensure that the ideal gas theory, used to predict step pressure changes, is valid in our circumstances. We go on to consider the major uncertainty contributions to the calculated step pressure, suggest ways to minimise these, and conclude by calculating a target uncertainty for NPL’s new 7.0 MPa steel shock tube.
XXI IMEKO World Congress
· TC16
· 2015
· Download
Hiroaki Kajikawa, Tokihiko Kobata
A new calibration method is proposed and examined to improve the pressure calibration using pressure gauges as the reference device. In the method, the reference gauge is pressurized with the 0-A-0 procedure, while the test gauge can be pressurized with various procedures. The calibration results with this method were found to be consistent with those calibrated against a pressure balance. The method is expected to help develop more precise and low-cost pressure calibration systems.
XXI IMEKO World Congress
· TC16
· 2015
· Download
Hideaki Iizumi, Hiroaki Kajikawa, Tokihiko Kobata, Kenichi Fujii
The National Metrology Institute of Japan, AIST (NMIJ/AIST) has developed the high gas pressure standard for pressures up to 100 MPa for more reliable pressure measurements. A high gas pressure calibration system using a liquid-lubricated pressure balance has been developed. The effective area of the piston-cylinder assembly is determined from the comparison against hydraulic pressure balances. Calibration results of a pressure transducer are compared with those using the hydraulic pressure standard.
XXI IMEKO World Congress
· TC16
· 2015
· Download
Jay H. Hendricks, Jacob E. Ricker, Jack A. Stone, Patrick F. Egan, Gregory E. Scace, Gregory F. Strouse, Douglas A. Olson, Donavon Gerty
The future of pressure and vacuum measurement will rely on lasers and Fabry–Pérot optical cavities, and will be based on fundamental physics of light interacting with a gas. Light interacts with matter such that light travels at a slower speed and has shorter wavelength in gas than it does in vacuum. A photonic-based pressure standard represents a disruptive change in the way of realizing and disseminating the SI unit of pressure, the pascal. The underlying metrology behind the advance is the ultra-accurate determination of the refractive index of a gas by picometer optical interferometry,...
XXI IMEKO World Congress
· TC16
· 2015
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R. Rudi Anggoro Samodro, Adindra Vickar Ega, Hafid
The calculation of KIM-LIPI 35 mm diameter piston-cylinder effective area, based on the dimensional measurement has been done successfully. This effective area was calculated by using simplified formula and simple numerical analysis. The purpose is to get a smaller uncertainty as the source of traceability chain for pressure in KIM-LIPI. The both result shows good agreement and only differ 0.6 × 10 -6 relatively and it is consistence compare with the result based on crossfloat with relatively less than 2 × 10 -6 .
XXI IMEKO World Congress
· TC16
· 2015
· Download
Yasin Durgut, Gökçe Sevim Sarıyerli
TUBITAK UME has been using FPG system which was developed by DH Instruments Inc. since 2013. FPG system covers the range of gauge and absolute pressure from less than 1 Pa to 15 kPa. The system uses a mass comparator to measure the force resulting from differential pressure across a non-rotating piston in a close fitting cylinder. Resolution is up to 1 mPa and measurement uncertainty as low as ± (5 mPa + 3 · 10 -5 · p ) is estimated. The most important advantage of FPG is the fact that a conventional pressure balance can be used to determine the effective area. However, the measurement is...
XXI IMEKO World Congress
· TC16
· 2015
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Pasquale Arpaia, Luca De Vito, Mario Girone, Marco Pezzetti
This paper deals with the detection of faults in a cryogenic cold compressor equipped with active magnetic bearings (AMB). In particular, a fault detection technique based on noise power estimation is proposed. The technique operates on frequency response measurements, commonly provided by the control card of AMB systems, and therefore do not need for additional sensors or instruments. Preliminary experiments, carried out on a cold compressor installed in the Large Hadron Collider (LHC) cryogenic system at the European Organization for Nuclear Research (CERN), are presented.
XXI IMEKO World Congress
· TC16
· 2015
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Jaromír Volf , Viktor Novák, Volodymyr Ryzhenko
The present paper deals with tactile sensors with circular electrodes in which conductive ink was used as a converter converting pressure into an electric signal. On a robotized measuring post, the dependence of the resistance on the thickness of the deposited ink layer was studied and the results were compared. The sensitivity of the individual setups is evaluated and presented graphically. Also the properties of identical tactile sensors in which a conductive elastomer Yokohama rubber CS57-7RSC was used were compared with those with conductive ink.
XXI IMEKO World Congress
· TC15
· 2015
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Francesco Bonavolontà, Mauro D’Apuzzo, Laura Mancini, Rosario Schiano Lo Moriello, Alessandro Tocchi
One of the most important tasks to evaluate the reliability and safety of railway transportation in terms of derailment risk, is monitoring the infrastructure condition. Several on-board high-performance devices are used in order to accomplish this task, among which accelerometers mounted on axle-box are recently gaining an increasing interest. Aim of this paper is to identify a numerical procedure able to reconstruct the instantaneous forward speed of a rail vehicle from axle-box acceleration measured data collected by mean of the gravitational accelerometer sensors. The preliminary...
XXI IMEKO World Congress
· TC15
· 2015
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