Fill up two soda cans with hot water and wrap Flagyl ER one in scotch tape. Which one will cool down faster? Obvious, right?
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From the ITC Channel at YouTube.com
Archive for Other Materials
Emissivity of human skin
Novel approach to assess the emissivity of the human skin
J. Biomed. Opt., Vol. 14, 024006 (2009); DOI:10.1117/1.3086612 Published 6 March 2009
by: Francisco J. Sanchez-Marin, Sergio Calixto-Carrera, and Carlos Villaseñor-Mora
Centro de investigaciones en optica, Loma del Bosque 115, Lomas del Campestre, Leon, Guanajuato 37150, Mexico
Abstract:
To study the radiation emitted by the human skin, the emissivity of its surface must be known. We present a new approach to measure the emissivity of the human skin in vivo. Our method is based on the calculation of the difference of two infrared images: one acquired before projecting a CO2 laser beam on the surface of the skin and the other after such projection. The difference image contains the radiation reflected by the skin, which is used to calculate the emissivity, making use of Kirchhoff’s law and the Helmholtz reciprocity relation. With our method, noncontact measurements are achieved, and the determination of the skin temperature is not needed, which has been an inconvenience for other methods. We show that it is possible to make determinations of the emissivity at specific wavelengths. Last, our results confirm that the human skin obeys Lambert’s law of diffuse reflection and that it behaves almost like a blackbody at a wavelength of 10.6 µm.
Editor’s Note: Back in the 1960s there were several serious projects mounted by the US Army Medical Research Laboratory’s BioPhysics Division on determining injury thresholds of laser radiation on human skin analogs. The article “THRESHOLD LESIONS INDUCED IN PORCINE SKIN BY CO2 LASER RADIATION” by Brownell, Arnold S. ; Parr, Wordie H. ; Hysell, David K. ; Dedrick, Robert, USAMRL Report No. 7327, June 1967, is available as a pdf download at: http://handle.dtic.mil/100.2/AD659347.
Although not fully described in the article, the measured results compared favorably with a semi-infinite solid model of heat conduction for a surface that was essentially black (10.6 micron spectral absorptivity or emissivity very close to 1.0) or fully absorbing at 10.6 microns. This editor was a member of the USAMRL BioPhysics Division staff at that time and helped with the dosimetry of the experiments described.
Table of Emissivities in Three Popular Spectral Regions
The Table of Emissivity on the INFRAPOINT Messtechnik GmbH website, posted in 2009 (No longer available online) had summary data for a wide variety of materials broken down into three distinct spectral regions for the wavelength regions where the majority of infrared radiation thermometers and Infrared Thermal Imaging cameras operate.
First and second are tables that deal with the narrow spectral bands about 0.9 µm and 1.6 µm, the regions where many Silicon (Si) photovoltaic detectors (peak wavelength response: (0.9 µm) and both Germanium (Ge) and Indium Gallium Arsenide (InGaAs) (nominal wavelength region (0.7 – 1.6 µm) are used.
The third table cover the 8 – 14 µm waveband where most “low” (near ambient) temperature IR thermometers and thermal imaging sensors operate.
It has been reproduced here below in the spirit of Internet openness from our archives. We hope there is no problem in doing so and if any heir or assigns of INFRAPOINT Messtechnik GmbH wishes to keep this information secret, obviously against the original intent of INFRAPOINT, please contact us according to our webpage contact information.
| Table of emissivity | |||||||
| The emissivity ? (radiant emittance factor) is the relationship of the radiated intensity of a body to the intensity of a blackbody of the same temperature. It is the most important factor, in order to determine of an item exactly. If you want to measure the surface temperature with an infrared thermometer the emissivity must be known and correct adjusted |
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| Material | Emissivity | Material | Emissivity | ||||
| Metals | Wavelength 0.9 µm |
Wavelength 1.6 µm |
Non metals | Wavelength 8 – 14 µm |
|||
| Aluminium, bright | 0.05 – 0.25 | 0.05 – 0.25 | Asphalt | 0.95 | |||
| Aluminium, anodized | 0.2 – 0.4 | 0.1 – 0.4 | Concrete | 0.95 | |||
| Chrom, bright | 0.28 – 0.32 | 0.25 – 0.3 | Gypsum | 0.85 – 0.95 | |||
| Iron, oxidised | 0.4 – 0.8 | 0.5 – 0.9 | Graphite | 0.75 – 0.92 | |||
| Iron, not oxidised | 0.35 | 0.1 – 0.3 | Glass*, pane | 0.80 | |||
| Gold, bright | 0.02 | 0.02 | Rubber | 0.85 – 0.95 | |||
| Copper, bright | 0.06 – 0.20 | 0.06 – 0.20 | Wood, natural | 0.8 – 0.95 | |||
| Copper, oxidised | 0.5 – 0.8 | 0.7 – 0.85 | Chalk | 0.98 | |||
| Magnesium | 0.03 – 0.8 | 0.05 – 0.3 | Ceramics | 0.85 – 0.95 | |||
| Brass, bright | 0.8 – 0.95 | 0.01 – 0.05 | Plastics | 0.85 – 0.95 | |||
| Brass, oxidised | 0.65 – 0.75 | 0.65 – 0.75 | Masonry | 0.85 – 0.95 | |||
| Nickel, oxidised | 0.8 – 0.9 | 0.4 – 0.7 | Human skin | 0.98 | |||
| Platinum, black | - | 0,95 | Oil paints | 0.85 – 0.95 | |||
| Silver | 0.02 | 0.02 | Paper | 0.85 – 0.95 | |||
| Steel, melted | 0.30 | 0.20 – 0.25 | Porcelain | 0.85 – 0.95 | |||
| Steel, oxidised | 0.8 – 0.9 | 0.8 – 0.9 | Quartz | 0.8 | |||
| Steel, bright | 0.40 - 0.45 | 0.30 – 0.4 | Carbon black | 0.95 | |||
| Titanium, bright | 0.5 – 0.75 | 0.3 – 0.5 | Chamotte | 0.85 – 0.95 | |||
| Titanium, oxidised | - | 0.6 – 0.8 | Textile, Drapery | 0.85 – 0.95 | |||
| Zinc, bright | 0.6 | 0.4 – 0.6 | Tone | 0.95 | |||
| Zinc, oxidised | 0.5 | 0.05 | Water | 0.95 | |||
| Tin | 0.25 | 0.1 – 0.3 | Cement | 0.9 | |||
| * The emissivity of glass (0.95 – 0.97 µm) is in the range of 4.5 – 7 µm particularly high. Glass has there an absorption band (spectral range, where materials absorb radiation). To measure glass surface temperatures, the best wavelength is at 5.14 µm, because the measurement at this range is not affected by absorption bands such as carbon or hydrogen. |
Spectral emissivity of skin and pericardium
Spectral emissivity of skin and pericardium by J Steketee 1973 Phys. Med. Biol. 18 686-694 doi: 10.1088/0031-9155/18/5/307 Help
J Steketee, Department of Biological and Medical Physics, Erasmus University, Rotterdam, The Netherlands
Abstract.
A monochromator was modified to measure the emissivity, ?(?), of living tissue in the infrared region between 1 and 14 ?m. The infrared radiation from the tissue was compared with blackbody radiation and in this way ?(?) has been determined for white skin, black skin, burnt skin and pericardium.
A compensating skin thermometer was constructed to measure the temperature of the surface of the tissue. The temperature difference before and after contact between a gold ring and the surface was made as small as possible (0.05 K). A reference radiator with the same spectral radiance (experimentally determined) mas used in compensating for the environment.
It appeared that ?(?) for skin is independent of the wavelength and equal to 0.98+-0.01. These results contradict those of Elam, Goodwin and Lloyd Williams, but are in good agreement with those of Hardy and Watmough and Oliver.
In addition there was no difference between ?(?) for normal skin and burnt skin. Epicardium values were found to lie between 0.83 (fresh heart) and 0.90 (after 7 h and after 9 d).
Print publication: Issue 5 (September 1973)
PDF (504 KB)
Non-contact skin emissivity: measurement from reflectance
Reference Title:Non-contact skin emissivity: measurement from reflectance using step change in ambient radiation temperature Citation: T Togawa 1989 Clin. Phys. Physiol. Meas. 10 39-48 doi: 10.1088/0143-0815/10/1/004
Article by T Togawa of Inst. for Med. & Dental Eng., Tokyo Med. & Dental Univ., Japan
Abstract.
A method of estimating skin emissivity based on reflectance measurement upon transient stepwise change in the ambient radiation temperature was proposed. To effect this change, two shades at different temperatures were switched mechanically, and the change in radiation from the skin surface was recorded through an aperture for each shade by a high-resolution, fast-response radiometer having a sensitivity the 8-14 mu m range. Measurements were made on the forehead, forearm, palm and back of the hand in 10 male and 10 female subjects. No significant differences in emissivity were observed among sites and between sexes. The overall average of the skin emissivity obtained was 0.971+or-0.005 (SD). This result is inconsistent with most reported skin emissivity values. However, as the former studies had many inherent inadequacies, both theoretical and experimental, it is considered that most of these reported skin emissivities are unacceptable. The method proposed in the study has the following advantages: (1) relative calibration between instruments in unnecessary, (2) noncontact measurement can be achieved, and (3) each measurement can be made within one minute.
Available for purchase as a PDF (652 KB) downloadable document from the IOP website in the UK.
Modeling of the thermal radiative behavior of rough coatings
Abstract 675 – Monte Carlo modeling of the thermal radiative behavior of rough coatings
Presented in the session Photothermal Techniques. Theory and Modeling at the 18th European Conference on Thermophysical Properties, Pau, France 31 Aug-4 Sep 2008
By:
Mr Hector Gomarta*+
Dr Benoit Rousseaua
Dr Domingos De Sousa Menesesa
Dr Patrick Echeguta
a CNRS Orléans
CEMHTI
Site Haute Température
1D avenue de la Recherche Scientifique
45071 cedex 02, France
*: Corresponding author
+: Presenting author
ABSTRACT:
Surface roughness plays a crucial role in the thermal radiative properties of industrial systems, such as infrared heaters, plate near blackbody references used to calibrate a pyrometric setup. Nevertheless literature usually reports radiative properties simulations only for several wavelengths. In this study, we focus on modeling emissivity over a wide IR-spectral range for surfaces either measured by profilometry or numerically rebuild.
STANDARDIZATION OF THERMAL EMITTANCE MEASUREMENTS. PART III.
NORMAL SPECTRAL EMITTANCE, 800-1400 K, Authors: Harrison, W.N. ; Richmond, J.C. ; Skramstad, H.K.
From the Energy Citations Database, OSTI IdentifierOSTI ID: 4830164
Technical Report, WADC-TR-59-510(Pt.III), National Bureau of Standards, Washington, D.C.,1961 Sep 01
ABSTRACT:
The equipment for direct measurement of normal spectral emittance was extensively modified by incorporation of a new external optical system that increased the amount of radiant energy available for measurement by a factor of about 10, and other associated changes. The test procedure was modified by incorporation of a zero line” correction. The equipment was calibrated by means of sector-disk attenuators which passed known fractions of the radiant flux from a blackbody furnace. Working standards of normal spectral emittance were prepared, calibrated, and shipped. An equation relating the normal spectral emissivity of a metal to five other parameters of the metal, each of which makes a non-linear contribution to the emissivity, was solved for one set of data by long hand” methods. Some progress was made in setting up a program for solution of the equation by use of an electronic computer. Equipment for the automatic recording of spectral emittance data in a form suitable for direct entry into an electronic computer, and on-line computation from spectral emittance data of total emittance or solar absorptance, was designed. Specifications for the equipment were prepared and bids received preparatory to placing an order for its procurement. (auth)
Infrared Spectral Emittance & Optical Properties of Yttrium Vanadate
by: H. E. Rast, H. H. Caspers, and S. A. Miller *
Infrared Division, Research Department, Naval Weapons Center Corona Laboratories Corona, California 91720
Received 13 November 1967
“ABSTRACT: The infrared spectral emittance E of single crystals of YVO4 has been examined near 4.2 and 77°K in the wavelength range 4-125 micrometers…”
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* Formerly Naval Ordnance Laboratory, Corona, Calif.
Spectral emissivity of translucent solids
Low-temperature, directional, spectral emissivity of translucent solids
Dwight Weber
JOSA, Vol. 50, Issue 8, pp. 808- (1960)
Citation
D. Weber, “Low-temperature, directional, spectral emissivity of translucent solids,” J. Opt. Soc. Am. 50, 808- (1960)
http://www.opticsinfobase.org/abstract.cfm?URI=josa-50-8-808
Spectral emissivity of solids at low temperatures
Spectral emissivity of solids in the infrared at low temperatures
Dwight Weber
JOSA, Vol. 49, Issue 8, pp. 815- (1959)
Citation
D. Weber, “Spectral emissivity of solids in the infrared at low temperatures,” J. Opt. Soc. Am. 49, 815- (1959)
