scholarly journals Assessment of uncertainties for measurements of total near-normal emissivity of low-emissivity foils with an industrial emissometer

2021 ◽  
Vol 10 (1) ◽  
pp. 135-152
Author(s):  
Jacques Hameury ◽  
Guillaume Failleau ◽  
Mariacarla Arduini ◽  
Jochen Manara ◽  
Elena Kononogova ◽  
...  
Keyword(s):  
Spectral Sensitivity ◽  
Radiation Source ◽  
Detection System ◽  
Measurement Techniques ◽  
Temperature Stability ◽  
Source Temperature ◽  
Uncertainty Sources ◽  
Radiometric Detection ◽  
Normal Emissivity ◽  
Emissivity Measurements

Abstract. The TIR100-2 emissometer (manufactured by Inglas GmbH & Co.KG) is an emissivity measurement device used by several producers of thermal insulation products for buildings and by some organizations certifying performance of insulation products. A comparison of emissivity measurements on low-emissivity foils involving different measurement techniques, including the TIR100-2 emissometer, gave widely dispersed results; the discrepancies were not explained. The metrological performance of the TIR100-2 emissometer and the uncertainties for measurement on reflective foils was not known, which could be detrimental to users. In order to quantify the performance of TIR100-2 devices for measurement of total near-normal emissivity of low-emissivity foils, the Laboratoire National de Métrologie et d'Essais (LNE) analyzed in detail the measuring principle and listed the associated assumptions and uncertainty sources. A TIR100-2 emissometer actually measures the reflectance and, for opaque materials, the emissivity is calculated from the measured reflectance. The parameters analyzed experimentally are the temperature stability and uniformity of the thermal radiation source, the emissivity of the radiation source, the response function linearity and the spectral sensitivity of the radiometric detection system measuring the reflected radiation, the size of the measurement area, and the measurement repeatability and reproducibility. A detailed uncertainty budget was established. The uncertainty sources taken into account are the uncertainties of the emissivities of the two calibrated standards used for calibration, the stability and uniformity of the radiation source temperature, the non-linearity and the spectral sensitivity of the radiometric detection system, the specific measurement condition related to the radiation source temperature, the uncertainties related to the temperatures of the standards and the sample, the noises on results, and the non-homogeneity in emissivity of the tested material. The combined measurement uncertainty was calculated for different types of reflective foils; the expanded uncertainty is around 0.03 for total near-normal emissivity measurements on smooth low-emissivity foils. A measurement campaign on five types of low-emissivity foils, involving four TIR100-2 emissometers, and a comparison to a primary reference setup at the Physikalisch-Technische Bundesanstalt (PTB) confirmed the uncertainties assessed.

Influence of different targets on halfraum radiation source temperature

2013 ◽  
Vol 25 (12) ◽  
pp. 3115-3118
Author(s):  
宋天明 Song Tianming ◽  
杨家敏 Yang Jiamin ◽  
朱托 Zhu Tuo ◽  
易荣清 Yi Rongqing ◽  
黄成武 Huang Chengwu
Keyword(s):  
Radiation Source ◽  
Source Temperature

scholarly journals High accuracy infrared emissivity between 50 and 1000 ᵒC for solar materials characterization

2020 ◽  
Vol 307 ◽  
pp. 01043
Author(s):  
Raquel Fuente ◽  
Telmo Echániz ◽  
Iñigo González de Arrieta ◽  
Irene Urcelay-Olabarria ◽  
Josu M Igartua ◽  
...  
Keyword(s):  
Basque Country ◽  
Temperature Stability ◽  
Spectral Emissivity ◽  
High Temperature Stability ◽  
Working Temperature ◽  
Material Efficiency ◽  
Solar Thermal Collector ◽  
Infrared Spectral ◽  
Materials Used ◽  
Emissivity Measurements

The total hemispherical emissivity of materials used in the solar energy industry is a critical parameter in the calculation of the radiative thermal losses and material efficiency, especially in solar thermal collector absorbing surfaces. This is because the radiative heat losses have a significant economic impact on the final cost of the electricity produced in solar plants. Our laboratory, HAIRL, in the University of the Basque Country (UPV/EHU) in Spain [1] is the first to have published infrared spectral emissivity measurements in Solar Absorber Surfaces (SAS) at working temperature [2]. The laboratory allows measuring between 50 and 1000 ºC in the 0.83-25 μm range and is also capable of doing directional measurements at different angles between 0 and 80 degrees. Therefore, it is suitable for measuring solar selective coatings, for studying high temperature stability and for characterizing thermal energy harvesting materials. In this presentation, we show the specifications of our laboratory, the results of spectral emissivity measurements in air-resistant solar selective coatings and in eutectic alloys for thermal storage and we demonstrate the necessity of measuring at working temperature in order to possess reliable data.

scholarly journals Fast neutron and γ-ray backscatter radiography for the characterization of corrosion-born defects in oil pipelines

2020 ◽  
Vol 225 ◽  
pp. 06009
Author(s):  
Mauro Licata ◽  
Helen M. O. Parker ◽  
Michael D. Aspinall ◽  
Manuel Bandala ◽  
Frank Cave ◽  
...  
Keyword(s):  
Fast Neutron ◽  
Radiation Source ◽  
Imaging System ◽  
Detection System ◽  
National Physical Laboratory ◽  
Pulse Shape Discrimination ◽  
Physical Laboratory ◽  
Γ Rays ◽  
Γ Ray ◽  
Mixed Radiation Field

In this research, a combined fast-neutron/γ-raybackscatter imaging technique is described. The aim of this work is to understand corrosion defects in pipelines by measuring differences in the scattered radiation flux, generated when different steel thicknesses are irradiated by a neutron and γ-ray focused beam. A californium-252 radiation source is used to produce fast neutron and γ rays, exploiting its spontaneousfission. This mixed radiation field is collimated and directed towards the steel samples. Backscattered neutrons and γ rays aremeasured as a function of the steel thickness using 4 liquid organic scintillation detectors linked to a real-time, pulse-shape discrimination system, which separates and retains the neutron and γ-ray event data. In this paper, we describe how, using asingle radiation source and detection system, it is possible to perform and combine two complementary imaging modalities. This research is validated by an MCNP6 computer simulation study. The backscatter imaging system developed for this research and the experimental results of the measurements carried out using the National Physical Laboratory neutron low-scatter facility are also presented in this paper.

Monochromatic radiation source for calibration of the relative spectral sensitivity of earth observation instruments

2010 ◽  
Vol 53 (7) ◽  
pp. 758-763
Author(s):  
S. P. Morozova ◽  
B. E. Lisyanskii ◽  
N. A. Parfentiev ◽  
A. S. Panfilov ◽  
A. N. Rybakova
Keyword(s):  
Spectral Sensitivity ◽  
Radiation Source ◽  
Earth Observation ◽  
Monochromatic Radiation ◽  
Observation Instruments ◽  
Earth Observation Instruments

Emerging Trends in 222Rn and 220Rn Decay Products Detection

2015 ◽  
Vol 238 ◽  
pp. 134-139 ◽  
Author(s):  
Rosaline Mishra ◽  
B.K. Sapra ◽  
Y.S. Mayya
Keyword(s):  
Background Radiation ◽  
Detection System ◽  
Measurement Techniques ◽  
Decay Product ◽  
Solid Particles ◽  
Wire Mesh ◽  
Flow Mode ◽  
Usual Practice ◽  
Gas Concentration ◽  
Decay Products

The importance of measuring the decay products of 222Rn (radon) and 220Rn (Thoron) is being realized by researchers as these are the major inhalation dose givers to the general population. Basically the decay products are radioisotopes of Polonium, Bismuth and Lead, which are solid particles. Upon inhalation, these particles deposit in different parts of the respiratory tract, undergo radioactive decay and irradiate the nearby tissues. So, the study of the behavior of the decay products in indoor air is important for assessing the natural background radiation exposures received by general populations through the inhalation route. Although the inhalation doses are predominantly due to decay products yet it had been the usual practice to measure the gas concentration rather than the decay products because of the complexities involved in their detection. The most common method is to derive the progeny concentration from the measured gas concentration using an assumed equilibrium factor. While this is fairly justified for radon in view of the short-lived nature of the progeny as compared to the gas, this approach is beset with serious limitations in thoron-rich environments. However, the development of passive detection system for the decay products known as deposition-based Direct Radon and Thoron Progeny Sensors, has provided a solution to the long standing problem of measuring the time integrated decay product activity concentration. These deposition sensors are calibrated against active measurement techniques, and provide an easy to use method for passive and simultaneous time integrated decay product measurement. In addition, for multi-parametric study, the different modes of these passive sensors, like flow-mode and wire-mesh capped mode, are also used. These are further discussed in the manuscript.

A Flush-Mounted Resonant Ice Detection Sensor with High Sensitivity

2012 ◽  
Vol 503 ◽  
pp. 81-86
Author(s):  
Qiang Shi ◽  
Jun Bo Wang ◽  
De Yong Chen ◽  
Yan Long Shang
Keyword(s):  
Resonant Frequency ◽  
Closed Loop ◽  
Detection System ◽  
Temperature Stability ◽  
High Sensitivity ◽  
Sensor Surface ◽  
Sensing Element ◽  
Ice Films ◽  
Ice Detection ◽  
Better Than

An ice detection system consisting of a resonant piezoelectric sensing-element and closed-loop circuit has been developed to automatically and distinctly sense ice films up to 1.3 mm thick. Accretion of ice and/or water on the sensor surface modifies the effective mass and/or stiffness of the vibrating transducer; these variations are sensed by measuring the changes in transducer resonant frequency. In case of ice films, resonant frequency of the transducer increases steadily from 60.9 kHz with no ice to 131.5 kHz when the ice film is 1.3mm thick. The time and temperature stability experiments revealed frequency variety no more than 1 kHz. The resolution of this sensor is better than 0.06mm.

scholarly journals Sound Power Estimation by Laser Doppler Vibration Measurement Techniques

1998 ◽  
Vol 5 (5-6) ◽  
pp. 297-305 ◽  
Author(s):  
G.M. Revel ◽  
G. L. Rossi
Keyword(s):  
Measurement Techniques ◽  
Acoustic Power ◽  
Industrial Applications ◽  
Laser Doppler ◽  
Vibration Measurement ◽  
Sound Power ◽  
Vibration Data ◽  
Uncertainty Sources ◽  
Intensity Measurements

The aim of this paper is to propose simple and quick methods for the determination of the sound power emitted by a vibrating surface, by using non-contact vibration measurement techniques. In order to calculate the acoustic power by vibration data processing, two different approaches are presented. The first is based on the method proposed in the Standard ISO/TR 7849, while the second is based on the superposition theorem. A laser-Doppler scanning vibrometer has been employed for vibration measurements. Laser techniques open up new possibilities in this field because of their high spatial resolution and their non-intrusivity. The technique has been applied here to estimate the acoustic power emitted by a loudspeaker diaphragm. Results have been compared with those from a commercial Boundary Element Method (BEM) software and experimentally validated by acoustic intensity measurements. Predicted and experimental results seem to be in agreement (differences lower than 1 dB) thus showing that the proposed techniques can be employed as rapid solutions for many practical and industrial applications. Uncertainty sources are addressed and their effect is discussed.

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