Glass radiative energy transfer

The only variables that are varied are thus the modeling of the radiative energy transfer in the melt, and the properties of the glass. The combustion space domain is simulated by... 

Reisfeld, R. Spectra and Energy Transfer of Rare Earths in Inorganic Glasses. Vol. 13, pp. 53-98. Reisfeld, R. Radiative and Non-Radiative Transitions of Rare Earth Ions in Glasses. Vol. 22,... 

Dysprosium ions Dy3+ can also be populated by direct absorption in the near U.V. part and blue part of the spectrum, or by energy transfer from U02+. The radiative transitions probabilities and branching ratios of Dy for tellurite and phosphate glasses have been calculated and measured51 and the corresponding values are given in Table 3. 

In fluids, the atoms and molecules may themselves migrate and set up convection currents or flow. Radiative heat transfer, on the other hand, requires no medium for transport. Thermal energy is carried with light-wave packets, called photons, and heats up the body when the body absorbs the photons. Whereas the phonon conductivity dominates heat transfer in the glassy state, transfer of heat in molten glass tanks is mostly due to radiative transfer and to some extent by convective and conductive transfer. 

In spite of the short radiative lifetimes of the order of 10 s, both luminescence (frequently Stokes-shifted to the violet or the blue) and energy transfer to other species present in a glass can show remarkably high yields. 

Radiative heat transfer across glass coated with gold nano-particles, H. Chowdhury, X. Xu, P. Huynh, and M. B. Cortie, ASME J. Solar Energy Eng., 2005,127, 70. 

An example of radiative transfer of energy between rare earth ions in glass was given by Cabezas and DeShazer (43). They suggest that the process might have potential laser applications. 

In the following sections we will look at the radiation properties of real bodies, which, with respect to the directional dependence and the spectral distribution of the radiated energy, are vastly different from the properties of the black body. In order to record these deviations the emissivity of a real radiator is defined. Kirch-hoff s law links the emissivity with the absorptivity and suggests the introduction of a semi-ideal radiator, the diffuse radiating grey body, that is frequently used as an approximation in radiative transfer calculations. In the treatment of the emissivities of real radiators we will use the results from the classical electromagnetic theory of radiation. In the last section the properties of transparent bodies, (e.g. glass) will be dealt with. 

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