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V. C. Fernicola, A. Frattolillo, L. Rosso, P. Vigo
NEW RESULTS IN MODELLING OF A SURFACE TEMPERATURE CALIBRATION SYSTEM

A dedicated calibration system for contact surface thermometers was designed and constructed and a thermal fluid dynamic model of the system for simulating the impact of the different influence parameters on the measurement was developed. The paper describes the new results of the comparison between the numerical predictions of the calibration system theoretical model and the experimental values, as obtained from its calibration.

Radek Kuchta,Radimir Vrba
WIRELESS TEMPERATURE MEASURING AND MONITORING SYSTEM

Knowledge of temperature course during a certain time is needed in scientific, medical and industrial applications. In some applications, however, the recorded temperature course should be read wirelessly.
This paper describes main principles applied in a set of mobile temperature data logger and portable interrogator with wireless transfer of digitized temperature values.

Alexandre Titov, Igor Malinovsky
PRECISION MEASUREMENT OF SELF-HEATING EFFECT OF RESISTANCE THERMOMETERS INSTALLED ON MATERIAL ARTIFACTS

Measurement of a self-heating effect (SHE) of a platinum resistance thermometer (PRT), which is to be performed under real experimental conditions, is the trickiest part in the calibration procedure of PRTs for precise temperature measurements of material artifacts. New double-channel synchronous detection technique has been developed for precise measurement of the SHE of a resistance thermometer, located on the surface of a material artifact. With new technique, we demonstrate that a PRT modifies the temperature distribution in the artifact, and the SHE of a PRT measuring a selected point on the artifact surface, is shown to depend on the distance from the thermometer to the selected point, the heat flux conditions in the artifact, and on the temperature rate, recorded by the thermometer. New approach, based on the use of pairs of specially calibrated thermometers, which are installed at a fixed distance on the artifact surface, realizes temperature measurements of the artifact surface without temperature gradient and velocity error. The demonstrated uncertainty in temperature measurement of gauge blocks inside our interferometers is at the level below 100 µK.

T. Katsumata, K. Morita, A. Okabe, H. Aizawa, S. Komuro, T. Morikawa
THERMALLY EXCITED LUMINESCENCE FROM RARE-EARTH DOPED SiO2 FOR FIBER-OPTIC THERMOMETER

Thermally excited luminescence from rare-earth element doped SiO2 fibers were studied for the fiber-optic thermometer application in high temperature. Thermal radiation similar to the black body radiation was observed in visible light region from the SiO2 fibers doped with Y, La, Ce, Pr, Eu, Tb and Lu. Visible light radiation peaks due to f-f transitions of rare-earth ions were clearly observed in the Nd, Dy, Er, Ho, Tm and Yb doped SiO2 fibers. Intensity ratio of thermal radiation at different wavelength is suitable for the highly sensitive temperature measurement. The hybridization of fluorescent thermometry and thermal radiation thermometry is suggested to extend the temperature range and increase the temperature resolution.

T. Katsumata, H. Kubo, S. Mochida, H. Aizawa, S. Komuro, T. Morikawa
HIGHLY SENSITIVE FLUORESCENCE THERMOMETER USING LONG AFTERGLOW PHOSPHOR

Long afterglow phosphorescent SrAl2O4 and CaAl2O4 based phosphors are found to be a useful sensor head material in the fluorescence thermometer because of extremely long fluorescence lifetime. Highly sensitive temperature sensor can be developed based on temperature dependence of afterglow intensity of long afterglow phosphor. Sensitivity of long afterglow phosphorescent SrAl2O4:Eu, Ln and CaAl2O4:Eu, Ln based phosphors are considered to be dominated by depth of the hole traps generated by doped rare-earth elements.

João Nildo de Souza Vianna,Michael E. K. de Almeida, Alberto C. G. C. Diniz, Alessandro B. S. Oliveira
MEASUREMENT UNCERTAINTY IN DYNAMIC CALIBRATION OF TEMPERATURE SENSORS

This paper presents a preliminary methodology for the calculation of measurement uncertainty of temperature sensors in dynamic regime. The experimental results show that the proposed methodology is suitable for the determination of the measurement uncertainty in the transient state of the calibration process.

Václav Kubernát
HEAT MEASUREMENT UNCERTAINTIES IN VERIFICATION IN METROLOGICAL LABORATORY

Heat-meters as a kind of revenue meters are metrologically certified and this certification is executed with some measurement uncertainty. Since these certifications are performed by means of temperatures and flow amounts simulations, it obviously results in some measurement uncertainty. The value of the measurement uncertainty can be seen in the following calculation.

Davor Zvizdic, Tomislav Veliki
TESTING OF THERMOCOUPLES FOR INHOMOGENEITY

It is good calibration practice to test thermocouples for homogeneity of the Seeback’s coefficient during calibration process. If change in homogeneity the coefficient, commonly known as inhomogeneity is not detected, thermometer although calibrated might not be able to measure temperature correctly. Several different testing techniques are developed, depending on type of the thermocouple and the equipment available. In order to automate process of thermocouple inhomogeneity testing for all applicable testing methods a Thermocouple Inhomogeneity Testing Device was developed in Laboratory for Process Measurement (LPM), University of Zagreb. The device is mostly used for the testing of thermocouple inhomogeneity in conjunction with heater moving along the thermocouple. The sled for mounting of the heater or the thermometer is translated by a threaded shaft and a step motor in horizontal axis, vertical axis or its sliding direction can be tilted in six steps between those two positions. Sled is mounted on shafts guides with precision linear ball bearing, which allow for smooth translation. The frame of the device is designed with adjustable height and distance between legs, which allows testing in most available metrological baths or furnaces. System is controlled by custom made program on LabView platform, with ability to automatically acquire, store and analyze data test data. Variation of the thermovoltage recorded during measurement is used in calculation of the uncertainty of the calibration. This paper describes the techniques for inhomogeneity testing and design of the testing device. Interpretation of the measurement results and calculation of inhomogeneity related component of the uncertainty budget is presented.

Masahiko Gotoh, Hideaki Oikawa
DEVELOPMENT OF DURABLE GOLD VERSUS PLATINUM THERMOCOUPLES

The gold versus platinum (Au/Pt) thermocouples are very stable under long term repeated usage at higher temperature. Still there are some unsolved problems that the stress-relieving coil at the top of measuring junction is deformed after thermal cycling. In this study twist pair of thermocouple-element and U shape thin Pt wire at the measuring junction instead of the coil are tested in addition to the ordinary measuring junction. It was found that good stability and immersion characteristic is realized by a thermocouple having ordinary junction with appropriate anchoring of the thermocouple elements.

Maurício Simões Lima, Renato Nunes Teixeira, Augusto Poças Cunha, Iakyra Borrakuens Couceiro
SPECTRAL RESPONSIVITY CALIBRATION OF THE LINEAR PYROMETER OF INMETRO

This paper describes in detail the spectral responsivity calibration of the Linear Pyrometer of the Thermal Metrology Division (Diter) of Inmetro. This calibration was performed at the Radiometry Laboratory (Larad) of the Optical Metrology Division (Diopt). It was made using two different experimental setups. In the first one, mirrors were used to direct the radiation beam from the exit slit of the monochromator to the entrance of the detectors. In the second setup the detectors were aligned directly in the exit slit of the monochromator. The spectral responsivity values in the first setup were lower than the second one. The uncertainty evaluation was performed for the second configuration data. The characterisation process of the linear pyrometer, will allow the maintenance of the International Temperature Scale of 1990 (ITS-90) on the instrument itself.

Page 856 of 938 Results 8551 - 8560 of 9371