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Davor Zvizdic, Tomislav Stasic, Lovorka Grgec Bermanec
CHARACTERIZATION OF LPM'S 1-T DEW POINT GENERATOR

This paper describes characterization of 1-T dew point generator developed at Laboratory for Process Measurement (LPM) self. Present operating range of generator is from -7°C to 18°C dew point range. The air flows through saturator in closed loop and is controlled with regulated flow meters. Air saturation degree is determined by measuring the temperature deviations between saturator air outlet and liquid in saturator. Thermometers are connected to the resistance bridge, which is in turn connected to the computer for data acquisition. The main design features of the 1-T generator are presented. The deviations between generated dew point temperature and LPM’s dew point transfer standard hygrometer (recently calibrated in PTB) are discussed. The deviations between saturator air outlet and liquid in saturator are also examined. The test results are presented in graphical and tabular form together with an example of uncertainty estimates for various test dew points.

Krzysztof Górecki, Janusz Zarebski
A NEW METHOD OF THE THERMAL RESISTANCE MEASUREMENTS OF MONOLITHIC SWITCHED REGULATORS

The problem of measurements of the thermal resistance (Rth) of monolithic switched regulators (MSR) is considered in the paper. A new method of measuring this thermal parameter is proposed and the proper measuring set is presented. The results of measurements of Rth of the considered devices are compared with the similar results obtained with two other known methods.

Krzysztof Strzecha, Anna Fabijańska
SEGMENTATION ALGORITHMS FOR INDUSTRIAL IMAGE QUANTITATIVE ANALYSIS SYSTEMS

In this paper computerized system for high temperature measurements of superficial properties has been presented. The process of superficial properties determination is based on digital image processing and analysis algorithms. Particular attention has been paid to adaptive thresholding algorithm with a local iterative threshold selection. Algorithm was elaborated to segment images obtained from the measurement process. Moreover, results of proposed algorithm have been presented. In the final stage of the paper difficulties appearing during high temperature measurements have been outlined. The authors have proposed methods of results correctness verification applying essential laws of the optics to a CCD camera lens.

Sergio Libanio Campos, José Luiz Fernandes, José Alberto Reis Parise
MECHANICAL FAILURE DIAGNOSIS IN AUTOMOTIVE AIR CONDITIONING SYSTEMS THROUGH THERMAL MEASUREMENTS

The present paper describes a simulation model for the operation of an automotive air conditioning system subjected to typical mechanical failures. A review identified the most common mechanical failures in automotive A/C systems. Simple mathematical models of two of the most common of these failures were developed and introduced in a simulation model of the vapor compression cycle. Simulated components of the cycle, operating trouble-free or under failure, included the compressor and the condenser. The evaporator, thermal expansion valve, filter-dryer, hoses and connections are also sources of failures and malfunctions. The modeling effort was employed to relate temperature and pressure field measurements with typical system failures. Uncertainties of these measurements and their effect in the predictions of the most probable system failures were studied with the simulation model, aiming at the standardization of mobile A/C system diagnosis procedures.

James Tennermann, Steven Santoro
HUMIDITY MEASUREMENT IN FUEL CELLS AND GAS TURBINES: PRACTICAL APPLICATION OF WARMED PROBE SENSOR TECHNOLOGY

This paper describes the practical application of humidity instrumentation for water management in fuel cells and inlet air monitoring of gas turbines. A description of the instrumentation is provided. Measurement challenges in each application are identified and successful solutions are described in detail.

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.

Page 854 of 936 Results 8531 - 8540 of 9356