Black absorber

The NO nitrosating agents present in the atmosphere are often due to air poUution. High surface area fillers such as carbon black absorb NO and Hberate it during the vulcanization process. Of course, this is the process where NO is most likely to be in contact with the various accelerators. 

To illustrate some of these principles the angular momentum of a photon will be examined [56]. Suppose a beam of circularly polarized light falls on a perfectly black absorbing surface, which not only heats up (E = hv) but also acquires a torque, on account of the angular momentum it absorbs. Circular polarization means that the probability of an elementary observation 0(P ) = The ratio of energy/torque = w(= 2m/), the angular frequency of... 

Wood charcoal at 0° C. readily absorbs gaseous sulphur dioxide up to a volume even exceeding 100 times that of the charcoal 5 platinum black absorbs the gas to a relatively slight extent.6 The gas is also absorbed very appreciably by caoutchouc, the process merely being one of solution.7 The adsorption of sulphur dioxide by silicic aeid... 

Five modules of the Telkes tilted single-effect still, totaling 500 sq. feet, will be constructed by the Curtiss-Wright Corp. and shipped, unassembled, to the Florida station. The tilted single-effect still is essentially a black absorbent fabric supported at an angle by an impermeable sheet of plastic or metal and surrounded by a transparent cover above and an opaque cover below. 

One way to reduce the free-convection heat loss in a horizontal solar collector is to reduce the pressure in the space separating the glass admitting the solar energy and the black absorber below. Assume the bottom surface is at 120°C and the top surface is at 20°C. Calculate the pressures that are necessary to eliminate convection for spacings of 1, 2, 5. and 10 cm. 

Nickel yields a tetracarbonyl when, in a finely divided condition, it is warmed in a current of carbon monoxide. Both palladium black and platinum black absorb carbon monoxide, yielding what appears to be a compound, although attempts to isolate the substance have not as yet proved successful. On heating to 250° C. the substances decompose, evolving carbon monoxide. 

When suspended in water palladium black absorbs even more hydrogen, namely, in one case 1204 times its own volume,3 Under similar conditions it likewise absorbs acetylene slowly when suspended in 60 per cent, alcohol it has a pronounced adsorptive action,4 as also when suspended in an aqueous solution of sodium protalbinate. The absorbed acetylene exhibits an enhanced chemical activity. The curves obtained by plotting the rate of absorption of hydrogen by platinum black are smooth, indicating that only one allotropic form of palladium is present.5... 

It has been known for some time that for efficiently reducing the reflectance of highly reflective substrate with a complex admittance (i.e. metals, or coated metals, such as an OLED), it is convenient to use simple metal-dielectric AR coatings similar to those used in black absorbers (Dobrowolski, 1981 Lemarquis Marchand, 1999) or heat-reflector in solar-cells applications (Macleod, 1978). This type of coatings has been demonstrated for the contrast-enhancement of electroluminescent (EL) displays (Dobrowolski et al., 1992) and on the cathode side of bottom-emitting OLED (see above) (Krasnov, 2002). 

The most common solar collector is the glass-covered flat plate type. Others include concentrating trough and tube-over-reflector collectors, and parabolic collectors. A flat plate collector uses a flat black absorber plate in a container box. Insulation behind the absorber plate and on the sides of the box reduce heat loss. The glazing may be flat glass, translucent fiberglass or clear plastic, on the sun side of the collector, 1 to 2 inches above the absorber. 

Fig. 7.13.21 shows a cross section of a thermoelectric infrared sensor. This structure has potentially low cost because of its high compatibility with the widely used SiCMOS ICs [4], To improve sensitivity, the sensor uses a swastika pattern with a curved beam and a gold-black absorber with good IR absorptivity so as to attain a UV absorption coefficient of 90% or larger. 

According to C. Paal, an aqueous suspension of palladium black absorbs 12,000 times its volume of Hg the dry material absorbs only 870 times its volume. 

To increase the rate of evaporation. Just think about how you feel on a hot summer day if you happen to be wearing black. The black absorbs the heat very efficiently, making you feel quite uncomfortable. White reflects heat — this explains why people tend to wear white clothing in the tropics. Blue is also very good at absorbing heat, although it s not as good as black. But there exists no appropriate, economic black dye that we can later remove from the salt residue. We can, however, easily remove the blue dye triphenylmethane from the salt once we ve purified it. 

Carbon black absorbs all wavelengths of UV light and converts it into heat, while physically blocking UV penetration. For UV-stabilizing effectiveness, various grades of carbon black can be compared in terms of impurity level (affecting taste or odor), particle size, dispersability, and moisture absorption in the compound (which can cause defects in the final part) [4-4]. 

A very simple design of air collectors is the polyethylene tube collector [41], A black absorber tube is placed inside a clear tube connected to the fan. The tube assumes its cylindrical form on overpressure. It can be laid on the ground in appropriate length, chiefly for agricultural drying purposes. 

Figure 14.25 shows the characteristics of a single-covering, air-type collector (black absorber) obtained by calculations [37]. 

In Figure 14.26, the instantaneous efficiency and the outlet temperature of a liquid-type collector (single-covering, steel finned tubes, black absorber) are illustrated as a function of liquid heat capacity flow rate [37]. The parameter is the irradiation. As the variations of I are accompanied by nonlinear heat transfer resistance variations, the curves for different I values deviate. The entry temperature of the medium is equal to the outside temperature (T j = TJ. 

FIGURE 14.28 Efficiency diagrams of collectors of different construction (1) black absorber, one covering (2) black absorber, two coverings (3) selective absorber, one covering (4) vacuum collector. 

L = phenylpyridine). Thus, the energy of the HOMO is varied to an extent of 1 V in this series of complexes [35]. Meyer and coworkers have used the same concept to synthesize black absorbers by judiciously selecting push and pull ligands [36]. 

If a deinitiator is combined with a chain terminator, then a greater effect is often achieved with respect to the inhibition periods and rate of absorption of oxygen than can be produced additively from the individual actions. This synergistic effect occurs because both compounds successively intervene in the reaction. Combinations leading to less effectiveness are also known (antagonistic effect). Antagonistic effects are observed in the decreased effectiveness of antioxidants in the presence of carbon black, since carbon black absorbs antioxidants, thus making them ineffective. 

Carbon black absorbs and scatters highly at NIR frequencies, making dark plastics difficult to probe Only limited polymers (and colors) can be detected StiU somewhat developmental... 

The so-called black absorber method may be used for the determination offs- This uses the saturation effect offs when the effective thickness, Ta (see Eq. (25.30)), approaches infinity. In this case, the asymptotic form of the spectral peak amplitude can be used to obtain fs. The measurement of the /factor of the absorber, is based on Eq. (25.33) and the corresponding nonlinear dependence of the intensity, amplitude, and width of the Mdssbauer spectrum peak on the effective thickness (see later in Fig. 25.17). This latter is the so-called blackness effect. For the determination of the peak intensity and the peak amplitude should be measmed for at least two absorbers of different thicknesses (Vertes and Nagy 1990). 

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