Configurational emissivity factor

Fn = view factor or geometric configuration factor E = emissive power of emitting surface 2 = incident radiation-receiving surface... 

In a joint research project in Sweden under the main title "Fire hazard - Fire growth in compartments in the early stage of development (pre-flashover)" (1, 2) a number of different factors have been studied. In the process of developing a full-scale fire test method - "room-corner" configuration - for surface lining materials, Nordtest NT-FIRE 025, the emission of smoke and gas was studied. That study covers data from thirteen different single and... 

The emission coefficient was taken to be a constant value close to unity. The configuration factor, F, was calculated in a conventional way, treating the center of each strip as a point. Once the downward flame spread started the radiation from the wall flames and the pyrolysing lining material behind the flames was added to the smoke layer radiation. The heat flux to the walls was then calculated from the expression... 

The factor G accounts for the difference in sensitivities for the detection of emission in the perpendicular and parallel polarized configurations. 

If the equilibrium position of the excited state C is located outside the configurational coordinate curve of the ground state, the excited state intersects the ground state in relaxing from B to C, leading to a nonradiative process. As described above, the shape of an optical absorption or emission spectrum is decided by the Franck-Condon factor and also by the electronic population in the vibrational levels at thermal equilibrium. For the special case where both ground and excited states have the same angular frequency, the absorption probability can by calculated with harmonic oscillator wavefunctions in a relatively simple form ... 

Unprimed, solid-line curves are photocurrent (left-hand scale) and primed, dotted-line curves are emission intensity (right-hand scale) monitored at Kmax 600 nm. Curves A and A result from excitation at 501.7-nm, 23°C Curves B and B from 514.5-nm, 23< C Curves C and C , 49°C and 501.7-nm excitation Curves D and D 86°C, 514.5-nm irradiation. Note that the ordinate of Curve D has been expanded by a factor of 10. Equivalent numbers of 501.7- and 514.5-nm photons were used to excite the photoelectrode in identical geometric configurations. The exposed electrode area is 0.41 cm2, corresponding to an estimated x for 501.7-nm excitation at 23°C and +0.7 V vs. Ag (PRE) of 0.50, uncorrected for solution absorbance and reflectance losses (9). 

A MCP is used in the PIMMS as a secondary electron multiplier (see Sect. 3.7). The electron current measured after MCP compared to the initial ion current is amplified by a factor of 10-1,000. The secondary electron emission coefficient is an averaged number of secondary electrons emitted after each impact. This number depends on the initial energies of the electrons or ions and so on the voltage applied to the MCP. The amplification factor of a MCP configuration is expressed as ... 

Related Calculations. If the six surfaces are not black but gray (in the radiation sense), it is nominally necessary to set up and solve six simultaneous equations in six unknowns. In practice, however, the network can be simplified by combining two or more surfaces (the two smaller end walls, for instance) into one node. Once this is done and the configuration factors are calculated, the next step is to construct a radiosity network (since each surface is assumed diffuse, all energy leaving it is equally distributed directionally and can therefore be taken as the radiosity of the surface rather than its emissive power). Then, using standard mathematical network-solution techniques, create and solve an equivalent network with direct connections between nodes representing the surfaces. For details, see Oppenheim [8],... 

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