Material surface temperatures, infrared

For the examination of the applied metallic or ceramic layer, the test object is heated up from the outside The heat applying takes place impulse-like (4ms) by xenon-flash lamps, which are mounted on a rack The surface temperature arises to approx 150 °C Due to the high temperature gradient the warmth diffuses quickly into the material An incorrect layer, e g. due to a delamiation (layer removal) obstructs the heat transfer, so that a higher temperature can be detected with an infrared camera. A complete test of a blade lasts approximatly 5 minutes. This is also done automatically by the system. In illustration 9, a typical delamination is to be recognized. 

The noncontact measurement principle, usually called optical or radiation temperature measurement, is based on detecting electromagnetic radiation emitted from an object. In ventilation applications this method of measurement is used to determine surface temperatures in the infrared region. The advantage is that the measurement can be carried out from a distance, without contact with the surface, which possibly influences the heat balance and the temperatures. The disadvantages are that neither air (or other fluid) temperature nor internal temperature of a material can be measured. Also the temper-... 

Generally speaking, the methods used to characterize carbonaceous material surfaces are referred to as wet and dry techniques. The former include potentiometric titrations and zeta potential or electrochemical methods the latter include temperature-programmed desorption (TPD) and spectroscopic methods such as x-ray photoelectron spectroscopy (XPS) and diffuse reflectance infrared spectroscopy (DRIFT). 

Zaki, M.I., Knozinger, H. (1987). Carbon Monoxide - a Low Temperature Infrared Probe for the Characterization of Hydroxyl Group Properties on Metal Oxide Surfaces. Materials Chemistry and Physics, Vol.l7, Nos.1-2, (April-May 1987), pp. 201-215, ISSN 0254-0584... 

Unlike plastics exposed on land, those exposed floating on the sea s surface do not suffer from heat buildup due to absorption of infrared radiation in sunlight, as the ocean acts as an efficient heat sink. As a result bulk temperatures of these materials remain much lower than those concurrently expected with on land exposure at the same location. (With on-land exposures, for instance, it is possible for dark-colored plastics to have a surface temperature that is higher by as much as 30°C compared to the ambient air.) This will significantly slow rates of degradation at sea. 

Raman spectroscopy has recently gained popularity for advanced chemical analysis of surfaces. In nanoscience, Raman spectroscopy is used to characterize surface properties of materials, measure temperature, and determine crystallinity. Raman spectroscopy is a spectroscopic technique used in material science to study vibrational and rotational frequencies in a system. The technique measures shifts in inelastic scattering, or Raman scattering, of light from a visible, near infrared or near ultraviolet light source and the shift in energy provides information about the material s surface characteristics. The Raman signal unit is a measurement of the ratio between the Stokes (down-shifted) intensity and anti-Stokes (up-shifted) intensity peaks. 

Materials are heated directly by infrared irradiation. Infrared lamps as well as hot rods and plates with efficient emission performance can be used as infrared sources. When wet materials are heated in the constant drying rate period by infrared radiation, the surface temperature increases to a temperature higher than the wet bulb temperature and the drying rate is enhanced. However, the drying operation must be... 

The infrared thermometer can record the surface temperature of the materials, while the metal thermocouples and the flber-optical temperature... 

Infrared thermal sensing and imaging instruments make it possible to measme and map surface temperature and thermal distribution passively and nonintrusively. In addition to the passive measurement of temperature distribution, thermographers have learned to use active or thermal injection techniques to study and evaluate the structural integrity of materials and fabricated bonds. 

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