Pyrometry

Radiant energy incident on a body is either reflected, transmitted through the body, or absorbed by it  

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Pyrometric cones Pyrometry Pyronaridine [74847-35-1] Pyromne B [2150-48-3] Pyromne G Pyrophosphatases Pyrophosphates... 

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). 

Thermal Applications. The protection of precious-metal thermocouples in high temperature pyrometry is an important appHcation of vitreous siHca. Although satin tubing is usually employed, transparent tubes are superior for protecting couples when used in a reducing atmosphere (220). 

Figure 3.16. Time-resolved shock luminosity record from one of the channels in a shock pyrometry experiment (Lyzenga and Ahrens, 1979).

Figure 4.25. Experimental configuration for optical pyrometry of shock temperatures induced in transparent minerals. Upon impact of projectile with driver plate, a shock wave is driven into the driver plate and then into the sample. Optical radiation from the sample is detected via six lens/interference filter channels and an array of six photodiodes. Signals from photodiode circuits are recorded on oscilloscopes operating in single sweep model. (After Ahrens et al. (1982).)...

Feuer-gefahrlichkeit, /. (in)fiammability. -gradmesser, m. pyrometer, -gradmessung, /. pyrometry. -gnibe, /. ash pit. -baken, m. fire hook, poker, -hsut, /. (fire-resistant) lining, liner, -holz, n. firewood, feuerig, a. = feurig. 

Variations of flame temperatures with exhaust-gas recirculation. Flame temperature maps are obtained by processing images obtained from a combustion chamber of a heavy-duty diesel engine using two-color pyrometry. Images are taken at 2° after the TDC at 1200rpm low-load condition. 

Hopkins M.F., Four-color pyrometry for metal emissivity characterization, Proc. SPIE, 1995 2599 294. 

Finally, it is to be expected that the evaporation coefficient of a very stable compound, such as alumina, which has a large heat of sublimation resulting from the decomposition into the elements, will be low. Since the heat of evaporation must be drawn from the surface, in the case of a substance with a low thermal conductivity such as an oxide, the resultant cooling of the surface may lead to a temperature gradient in and immediately below the surface. This will lower the evaporation rate compared to that which is calculated from the apparent, bulk, temperature of the evaporating sample as observed by optical pyrometry, and thus lead to an apparently low free surface vaporization coefficient. This is probably the case in the evaporation of alumina in a vacuum,... 

Of course, the temperature probes discussed could be further classified according to specific applications, e.g., biomedical temperature measurement, high temperature sensing up to >500°C, and the pyrometry range (> 500°C).The development of the temperature probes for such applications cited is discussed where specific applications are concerned. 

Cross-Referencing of Fluorescence Thermometry with Blackbody Radiation Pyrometry... 

Nd YAG and the lifetime measurement is made by the use of the phase-locked detection of fluorescence lifetime (PLD) scheme. By reference to the use of the fluorescence lifetime measurement, the problems, in pyrometry, of emissivity, and sight path factor in the blackbody radiation measurement could be corrected in such a scheme having an internal self-calibration. ... 

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... 

Figure 42 shows the temperatures measured by two-color pyrometry for step changes in temperature compared with the true temperature and calculated temperatures based on the response characteristics of the detectors (time constant = 0.311 s). The response speed of the detectors in this case was too slow to follow the actual temperature decrease, but the temperature rise is reasonably well detected. Spjut and Bolsaitis reported that two-color temperatures are unreliable when the optical properties of the microparticle change during the experiment, but they showed that single-wavelength temperatures can yield consistent results and, with some caveats, are adequate for particle temperature measurement. 

Fig. 42. The response to a step increase (a) and a step decrease (b) in temperature of a laser-heated particle, from Spjut and Bolsaitis (1987). The data were obtained using two-color pyrometry, and the calculated curves are based on the response characteristics of the detectors.

Claude-Auguste Lamy, 1820—1878. President of the SociSte Chimique de France in 1873 The first person to prepare an ingot of metallic thallium. He made a thorough study of its compounds and proved that they are poisonous Author of many papers on optics, electricity, pyrometry, organic and inorganic chemistry, and sugar technology. 

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. 

It is known that initiation of solid TNT to explosion cannot be caused by local heating to high.temperature, unless the material contains some bubbles of gas, such as air, At, etc. This means that the presence of gas bubbles is of importance, although they do not seem to take part in the chem reaction. The luminescence of these gases on shock heating plays the decisive role. By 2-color pyrometry with electronic amplification the temp... 

Harrison, T. R. Radiation Pyrometry, John Wiley and Sons, Inc., New York 1960... 

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. 

In optical pyrometry the size of the luminous object must meet a certain minimum, and the radiant energy output must be uniform over the area observed, lest the apparent temp be low. Moreover, temp readings will be low if radiant energy is absorbed in the colder outer gas envelope. The role of smoke and other debris in the study of expls was alluded to in an earlier article ( Spectroscopy of Energetic Materials in this Vol). There, too, was referenced rapid scan spectroscopy for the resolution of pyrot phenomena, and of the energetics of fuel-air expins. For more extensive discussions of high temp measurement techniques, see Ref 6a... 

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). 

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... 

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