SpectralEmissivity & Emittance

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Influence of KMnO4 Concentration on Infrared Emissivity of Coatings

On TC4 Alloys by Micro-Arc Oxidation (Materials EISSN 1996-1944)


Figure 8. Infrared emissivity curves of the MAO ceramic coatings with different KMnO4 concentrations within a waveband of 5–20 μm.

Figure 8. Infrared emissivity curves of the MAO ceramic coatings with different KMnO4 concentrations within a waveband of 5–20 μm.

Ceramic coatings with high emissivity were fabricated on TC4 alloys by micro-arc oxidation technique (MAO) in mixed silicate and phosphate electrolytes with varying KMnO4 addition.

The microstructure, phase and chemical composition were characterized by scanning electron microscope (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS), and the infrared emissivity of the MAO coatings was measured in a waveband of 5–20 μm.

The results show that the thickness of the coatings increased with the addition of KMnO4, but the roughness of the coatings first decreased and then increased slightly due to the inhibitory effect of KMnO4 on Na2SiO3 deposition. Read More

Retrievals of the Far Infrared surface emissivity over the Greenland Plateau

Research Article


TITLE: “Retrievals of the Far Infrared surface emissivity over the Greenland Plateau using the Tropospheric Airborne Fourier Transform Spectrometer (TAFTS).”

(See Author List below)

ABSTRACT (Format Edited for easier online viewing)

The Tropospheric Airborne Fourier Transform Spectrometer (TAFTS) measured near surface upwelling and downwelling radiances within the far infrared (FIR) over Greenland during two flights in March 2015. Here we exploit observations from one of these flights to provide in-situ estimates of FIR surface emissivity, encompassing the range 80-535 cm-1.Read More

Reflectivity of Mineral Powders

From the Website of Ocean Optics, an applications note for their Jaz Spectrometer

 Figure-3-Experiment-Setup.jpgIt begins:

“Reflectance spectroscopy is a versatile technique than can be used to identify and characterize a range of powdered samples including mineral powders, grains in lunar samples, mining samples, natural deposits, soils and sediment core samples. In this application note, reflectance spectroscopy is used to characterize mineral powder samples.

The Jaz spectrometer was used to acquire reflectance spectra for pure samples and powder mixtures to assess the power of reflectance spectroscopy to characterize mineral powder samples.”

Figure-3-Experiment-Setup.jpg from the Ocean Optics Blog

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Noncontact multiband emissivity measurements

Proc. SPIE 5124, 240 (2003); doi:10.1117/12.517121
Conference Title: Optoelectronic and Electronic Sensors V
Conference Chairs: Wlodzimierz Kalita


Adam Mazikowski
Gdansk Univ. of Technology (Poland)

During last decade an increasing interest in passive multiband systems for temperature measurement was noted. However, recent studies showed that multiband systems are capable of producing accurate results of non-contact temperature measurement only in limited number of applications. Available literature about passive multiband systems concentrated exclusively on problem of temperature measurements too. A model of a passive multiband system for non-contact emissivity measurement has been developed and presented in this paper. Simulations carried out using this model showed that it is possible to achieve reasonable accuracy of emissivity measurements with passive multiband systems and these systems can be considered as an attractive solution for emissivity measurements in industrial conditions.Read More

Emissivity of Human Skin in the Waveband between 2 & 6 micrometers

From a Nature Article of the same title:

By DAVID J. WATMOUGH & R. OLIVER, Department of Radiation Physics, Churchill Hospital, Oxford.
Citation: Nature 219, 622 – 624 (10 August 1968); doi:10.1038


The emissivity of human skin epsilon(lambda) in the range 2micro to 6micro has recently assumed considerable importance because of the increasing medical use of infrared scanners to measure skin temperature (t). Several commercially available scanners utilize indium antimonide detectors which are sensitive in the range 2micro to 5.4micro . Such machines measure the energy (Q) Bactrim radiated by the skin and, being calibrated against a standard black body, changes in Q are represented as variations in skin temperature. Dreyfus1 has shown that Q is related to t by an equation of the form, where k is a constant, and where the index n depends on lambda as lambdamax being the wavelength corresponding to the maximum in the emission curve. The importance of variations in emissivity can be seen by differentiating equation (1) for constant Q. We obtain which simplifies to give for Deltat For a skin temperature of 27° C (t=300° K), n is about 12.5. It follows from equation (2) that if epsilon(lambda) were to vary by as much as 5 per cent over the skin surface, this would be interpreted by the scanner as a temperature variation of about 1° C. A fairly accurate knowledge of epsilon(lambda) is thus necessary, for hot spots with temperature elevations of only 2° C are considered to be of clinical significance.

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