Infrared pyrometry

A significant concern in the use of total radiation pyrometry is that it must be calibrated at the distance it will be from the source because of the influence of the atmosphere. Normal atmosphere contains a small fraction of carbon dioxide and water vapor (the latter dependent on the relative humidity, which varies with the day). When combustion is used for furnace heating (e.g. CH4+2O2 = 2H2O+CO2), water vapor and carbon dioxide are the predominant, atmospheric constituents. As 

In this chapter, five methods of determining the thermal conductivity of solids are described. The final technique, laser flash, is a method of measuring the thermal diffusivity, from which the thermal conductivity may be obtained if the specific heat and density are known. In the following sections, the operating principles of each technique are described. Novel techniques for measurements of this form appear every year— reference [l] is suggested for a start on contemporary literature. 

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The use of the infrared pyrometric method extended significantly the range of measurement. Infrared pyrometry has the advantage of being equally adaptable to luminous low-transparency and to nonluminous flames. 

The former French company Prolabo developed two microwave systems for synthesis7. The machines were employed in several research laboratories mainly for solvent-free organic chemistry. They had monomodal rectangular waveguide sections that also served as microwave cavities. Cylindrical tubes could be inserted and rotated to increase thermal homogeneity and if required condensers could be fitted. Temperature measurement was by infrared pyrometry. Computer control enabled reaction monitoring with respect to temperature or power. 

Cox and Macosko (19) have reported experimental results on measurements of the melt-surface temperature upon exit from the capillary using infrared pyrometry, which senses the radiation emitted by the hot polymer melt surface. Their work also included the numerical simulation of viscous heating in a capillary, a slit, and an annular die, using a method resembling that of Gerrard et al. (13). They used a boundary condition at the die wall in between the isothermal and adiabatic case, —k(dT/dr) = h T — To) at the wall, where 7o is the die temperature far from the melt-die interface as well as the inlet melt... 

The hot char [300 to 1000 C as measured by infrared pyrometry (44)] and ash provide surfaces which can catalyze secondary thermal reactions of the reactive fragments of the escaping volatiles. The char can also be consumed by them as suggested by Lewellyn et al. However, both processes occur at temperatures lower than the effective plasma temperature and degradation is not as severe. 

Infrared pyrometry Determination of the temperature of a surface by measuring the IR radiation emitted from it. Useful in temperamre ranges below those at which optical pyrometry (color temperature) is used. See also Optical pyrometry. 

Optical pyrometry The determinahon of the temperature of a surface by observing its color temperature, usually by comparing its color to the color of a surface at a known temperature. See also Infrared pyrometry. 

Lead Telluride. Lead teUuride [1314-91 -6] PbTe, forms white cubic crystals, mol wt 334.79, sp gr 8.16, and has a hardness of 3 on the Mohs scale. It is very slightly soluble in water, melts at 917°C, and is prepared by melting lead and tellurium together. Lead teUuride has semiconductive and photoconductive properties. It is used in pyrometry, in heat-sensing instmments such as bolometers and infrared spectroscopes (see Infrared technology AND RAMAN SPECTROSCOPY), and in thermoelectric elements to convert heat directly to electricity (33,34,83). Lead teUuride is also used in catalysts for oxygen reduction in fuel ceUs (qv) (84), as cathodes in primary batteries with lithium anodes (85), in electrical contacts for vacuum switches (86), in lead-ion selective electrodes (87), in tunable lasers (qv) (88), and in thermistors (89). 

Spjut and his associates heated levitated microparticles and measured their temperatures radiometrically. They levitated a microparticle in a bihyperbol-oidal quadrupole, and they irradiated the particle from opposite sides by splitting a cw CO2 laser beam and directing the beams by means of mirrors to illuminate the particle symmetrically (Spjut et al., 1987). The particle temperature was measured by multiple-color pyrometry (Spjut, 1987 Spjut and Bolsaitis, 1987) using narrow-band infrared detectors. The temperature... 

Because the spatial area with higher temperature on the catalyst surface of one of the samples of the library is very small the detection of catalytic activities through temperature measurement cannot be carried out by direct temperature measurements but only by non-contact methods such as pyrometry or IRT. The IR video camera used here measures the emission at every point of the library in parallel. The detector consists of a 256x256 pixel array of Pt-silicide-IR-sensors. Each pixel delivers a voltage-signal that depends on the infrared radiation and the sensitivity of that pixel (fixed pattern noise). 

This monograph, I believe, is unique in that it covers the broader topic of pyrometry the latter chapters on infrared and optical temperature measurement, thermal conductivity, and glass viscosity are generally not treated in books on thermal analysis but are commercially and academically important. I have resisted the urge to elaborate on some topics by using ex-... 

Pyrometry is thought to be the most feasible method to extract quantitative information from radiation spontaneously emitted from flames. Temperature distributions over large regions of the flame can be derived by applying the Plank law to every pixel of a CCD sensor. Two-color techniques are usually applied, due to its reduced sensitivity to uncertainties in emissivity or attenuation. Infrared cameras are used in most cases, as radiation levels are highest in this region of the spectrum [4-7]. Two channels of RGB video cameras have been also used in some works [8] although less accurate, this has the... 

Many different methods have been used to monitor the kinetics of cationic ring-opening photopolymerizations. Among the most commonly used techniques are real-time infrared spearoscopy, differential scanning photocalori-metry, " thin-film calorimetry, and optical pyrometry. ... 

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