Voluminal emission

Two main types of models for tubular lamps (the most widely used) will be described. There are lamps that produce an arc that emits radiation and, consequently, photons come out directly from such an arc. Emission is made by the whole lamp volume. We call this process Voluminal Emission. There are other types of lamps in which the discharged arc between electrodes induces an emission produced by some particular substance that has been coated on the lamp surface. We call this process Superficial Emission. Voluminal emission may be safely modeled as an isotropic emission in this case the specific intensity associated with each bundle of radiation originated in some element of volume of the lamp is independent of direction, and the associated emitted energy (per unit time and unit area) is also isotropic (Figure 6.6). On the other hand, it seems that superficial emission can be better modeled by a diffuse type of emission that is also known as one that follows the Lambert s cosine law of emission in this case the emitted intensity is independent of direction but the emitted energy depends on the surface orientation and follows the cosine law equation (Figure 6.7). The following assumptions are made (Irazoqui etal., 1973) ... 

Figure 6,6 The extended source with the voluminal emission model for the lamp. Adapted from Cassano etal. (1995)...

The boundary conditions when a lamp with voluminal emission is employed results in ... 

Limits of integration for the 3D emission models. When a lamp with superficial emission is used, according to equation 6.38, a constant value must be incorporated as a boundary condition. Conversely, when lamps with voluminal emission are used, according to equation 6.51, the boundary condition infioduces a function of x, 0, and . The limits of integration for the annular reactor with the tubular lamp were derived by Irazoqui etal. (1973) and systematically described by Cassano etal. (1995). They are... 

All the elements in the Level 1 scheme have been utilized in studies of discharges from industrial and energy processes. The data developed is far too voluminous to be presented here and the results discussed are, therefore, more a demonstration of the utility and viability of selected elements within the scheme. It should also be noted that all the data presented was acquired to evaluate the Level 1 methodology and should not be interpreted as indicative of emissions from the processes studied. 

DeMent (Ref) proposed to use the following Co ion contg mixts as smoke-producing pyrotechnic compns a)Co stearate 2.0, K chlorate 10.0 to 12.0 Amm acid fluoride 4.0 to 8.0 parts. This compn, when ignited by a flame, produced a heavy, voluminous fine white smoke b)When using monochloroacetic acid in previous mixt, instead of fluoride, the color of smoke produced was blue-white c)Equal parts of Co chloride, K bromate, K bromide, sulfur, K chlorate K acid sulfate burned with the emission of a green to green-brown smoke d)Equal parts of Co nitrate, K bromate, K bromide, sulfur, K chlorate K acid sulfate burned with the emission of grn to gm-bm smoke e)A mixt of Co chloride 1.0, K chlorate 2.0,K iodate 1.0, K iodide 1.0 sulfur 1.5 parts burned with evolution of a heavy voluminous deep violet smoke Ref J.DeMent, USP 2995526 (1961), p8... 

When the lanthanide ion is surrounded by voluminous polarizable anions like chloride, bromide, or sulfide ions, the Stokes shift is generally small. At low temperatme, a zero-phonon line is present in absorption and emission spectra, in addition to the band corresponding to transitions involving absorption or emission of phonons (vibronic transitions). Low... 

This chapter will focus on processes leading to the formation of localized excited states, excimers and exciplexes by annihilation of radical ions in solution. The article will not deal with either direct absorption or emission from intreimolecular charge-transfer excited states. In addition, the voluminous literature in this area prohibits any attempt to comprehensively cover published work in the space avail-... 

Applications of this process at an industrial scale have been in the area of removal of light colloidal systems such as emulsified oil, ions, pigments, ink, and fibers from water (36,37). The advantages of this process are the clarity of the treated wastewater and the disadvantages are the low throughput, the emission of H2 bubbles, electrode costs and maintenance, and the voluminous sludge produced (24). 

When emission is voluminal, each of the differential volumes of emission is transparent to the emission of its surroundings (a possible questionable approximation). 

Three-dimensional source with voluminal isotropic emission. The E-VIE source model. Since emission is produced by a volume, the radiative transfer equation can be applied inside the lamp. There is no absorption (assumption 4) and no scattering. For isotropic and uniform emission... 

Reactor model. The reactor model was constructed according to the following sequence (i) the annular reactor, radiation distribution model of Romero etal. (1983) was adapted for this particular set-up (ii) the tubular lamp with voluminal and isotropic radiation emission model was applied to this system (iii) a mass balance for an actinometric reaction carried out in a tubular reactor inside the loop of a recycling system was adapted from Martin etal. (1996) and (iv) the verification of the radiation model, actinometer experiments were performed in the reactor to compare theoretical predictions... 

The boundary condition was obtained from the 3D with voluminal and isotropic emission model (equation 6.51). The solution of equation 6.23 provides values of the radiation intensity as a function of position (r, z) and direction (, ). Once is known, the incident radiation and the LVRPA can be obtained from equations 6.24 and 6.25. Since monochromatic radiation is employed, no integration over wavelength is needed. The final equation for calculating the LVRPA is... 

There is a voluminous hterature concerned with the study of flame spectra, but the application of spectroscopy to the study of flame kinetics followed the introduction of flame photometry as a general analytical tool. The chief interest before this was in the spectra of the flames, which could serve to demonstrate the presence of intermediates in the combustion process. These were in general detected by the emission spectra of excited species and therefore were not necessarily indicative of the concentrations of ground state species. The difficulties of constructing burners which were sufficiently large and uniform to allow the study of absorption spectra prohibited a measurement of the species in their ground states, until the development of the multiple pass technique. ... 

It is gratifying to find evidence in a voluminous report Symposium on Thermal Radiation of Solids of the large amount of work, both experimental and theoretical, on radiant emission of solids related to space technology. But closer inspection of these informative reports yields few applicable data for our specific area of investigation. 

The literature describing the theoretical as well as design and operational aspects of the Claus process is quite voluminous. In view of this extensive coverage, the following discussion will be directed primarily toward current technology on the design and operation of plants that provide high efficiency sulfiir recovery and low emission of sulfiirous pollutants to the atmosphere. 

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