Spectral Emissivity Measurements

Watanabe, Hirokazu; Ishii, Juntaro; Wakabayashi, Hidenobu; Kumano, Tomoyuki; Hanssen, Leonard M.

doi:10.1016/b978-0-12-386022-4.00009-1

Cited by 22 publications

(7 citation statements)

References 42 publications

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“…Temperature measurements with a single-color pyrometer require knowledge of spectral emissivity and its temperature dependence. These data for refractory oxides above 2000 °C are fragmentary [ 70 ]. For opaque materials, the sum of emissivity and reflectivity at given wavelength must be equal to one.…”

Section: Resultsmentioning

confidence: 99%

Measurements of Density of Liquid Oxides with an Aero-Acoustic Levitator

et al. 2021

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Densities of liquid oxide melts with melting temperatures above 2000 °C are required to establish mixing models in the liquid state for thermodynamic modeling and advanced additive manufacturing and laser welding of ceramics. Accurate measurements of molten rare earth oxide density were recently reported from experiments with an electrostatic levitator on board the International Space Station. In this work, we present an approach to terrestrial measurements of density and thermal expansion of liquid oxides from high-speed videography using an aero-acoustic levitator with laser heating and machine vision algorithms. The following density values for liquid oxides at melting temperature were obtained: Y2O3 4.6 ± 0.15; Yb2O3 8.4 ± 0.2; Zr0.9Y0.1O1.95 4.7 ± 0.2; Zr0.95Y0.05O1.975 4.9 ± 0.2; HfO2 8.2 ± 0.3 g/cm3. The accuracy of density and thermal expansion measurements can be improved by employing backlight illumination, spectropyrometry and a multi-emitter acoustic levitator.

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Section: Resultsmentioning

confidence: 99%

Measurements of Density of Liquid Oxides with an Aero-Acoustic Levitator

et al. 2021

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“…However, the results are subject to systematic error due to the complexity and uncertainty augmented by multiple instruments involved in this technique 18 . The instrumental setup and signal evaluation technique of the direct radiometric method is discussed in detailin a review paper by Honner and Honnerová 19 , as well as in a book chapter by Watanabe et al 20 …”

Section: Measurement Of Emittance At High Temperaturementioning

confidence: 99%

Radiation heat transfer during hypersonic flight: A review of emissivity measurement and enhancement approaches of ultra‐high temperature ceramics

Saad

Martínez

Trice

2023

Int J Ceramic Engine & Sci

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Emissivity as a function of wavelength, direction, and temperature correlates to a material's efficiency in radiating thermal energy. Knowledge of emissivity is essential for designing and developing radiation-cooled thermal protective systems for hypersonic applications. It is desirable to achieve a high emissivity (with a value close to 1) to maximize heat radiation from a hot surface of a hypersonic vehicle's leading edge during atmospheric re-entry. With the goal of providing the hypersonic materials community with this necessary knowledge, this article offers a basic understanding of thermal radiation, methods for measuring emissivity at high temperatures, and a comprehensive overview of the emissivity of ultra-high temperature ceramics.

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“…For real materials, the ε constant representing the emissivity of the surface at defined λ and T is introduced. Thus, Equation (14) becomes:

where ε is always <1. ε is experimentally determined and depends on the emitting angle and the temperature of the radiating body, as well as the physical (i.e., geometry and roughness) and chemical (i.e., contamination) features of the emitting surface [ 184 ]. Fixed ε and σ, and knowing the emissivity spectrum of a specific tissue of the human body at a given temperature, it is possible to trace the thermal information (i.e., T ) by comparing the measured λ with the reference one.…”

Section: Non-invasive Solutions For Myocardial Temperature Evaluatmentioning

confidence: 99%

Techniques for Temperature Monitoring of Myocardial Tissue Undergoing Radiofrequency Ablation Treatments: An Overview

Zaltieri

Massaroni

Cauti³

et al. 2021

Sensors

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Cardiac radiofrequency ablation (RFA) has received substantial attention for the treatment of multiple arrhythmias. In this scenario, there is an ever-growing demand for monitoring the temperature trend inside the tissue as it may allow an accurate control of the treatment effects, with a consequent improvement of the clinical outcomes. There are many methods for monitoring temperature in tissues undergoing RFA, which can be divided into invasive and non-invasive. This paper aims to provide an overview of the currently available techniques for temperature detection in this clinical scenario. Firstly, we describe the heat generation during RFA, then we report the principle of work of the most popular thermometric techniques and their features. Finally, we introduce their main applications in the field of cardiac RFA to explore the applicability in clinical settings of each method.

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Spectral Emissivity Measurements

Cited by 22 publications

References 42 publications

Measurements of Density of Liquid Oxides with an Aero-Acoustic Levitator

Measurements of Density of Liquid Oxides with an Aero-Acoustic Levitator

Radiation heat transfer during hypersonic flight: A review of emissivity measurement and enhancement approaches of ultra‐high temperature ceramics

Techniques for Temperature Monitoring of Myocardial Tissue Undergoing Radiofrequency Ablation Treatments: An Overview

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