Optical mass

Mass Optical Density of Smoke from NBS Smoke Chamber. Figure 5 shows the data for the mass optical density measured in the NBS smoke chamber for the flaming and nonflaming fires under static conditions. For MTL 1 and 2 samples, the MOD values in flaming fires are lower than in the nonflaming fires. For the other three samples, for which the MOD values are smaller, the trend is reversed. 

Figure 5. Mass Optical Density of Smoke Measured in the NBS Smoke Chamber for the Fiber Reinforced Composite Materials...

Figure 6. Correlation Between the Mass Optical Density Data for Fiber Reinforced Composite Materials Measured in the FMRC Small-Scale Flammability Apparatus for Flaming Fires and the NBS Smoke Chamber for Flaming and Non-Flaming Fires...

The alternative to sapphire and its complement is diamond. Type II diamond is transparent for wavelengths of 0.4 fjim and above, except between 4 and 6 ji,m where two-phonon absorption bands occur. Type I diamonds have an additional nitrogen absorption band at around 7.5 xm. The initial cost of diamond windows is more than offset by their performance, which allows very-low-mass optical plugs and cells to be used, and thus there is a considerable... 

Instead of the specific optical density, the authors suggested that the optical density should be related to the mass of the material burnt away (mass optical density, MOD), It was theoretically and experimentally demonstrated that this value is less dependent on the thickness and density of the specimen. 

Replacing the exposed area by the mass loss (m), the mass optical density is... 

Fig. 4.11 Time plots of mass optical density (MOD) for various burning materials 1 PVC 2 poly(methyl methacrylate) i. red wood 4 Douglas fir marine plywood 5 a-cellulose 6 flexible polyurethane foam 7 plasticized PVC 8 neoprene Reprinted from Ref. 14. See footnote of Fig. 4.8...

The results are interpreted by using the maximum mass optical density in m kg as introduced by Seader et al. ... 

It should be noted that the mass optical density (MOD) could also be calculated in these large-size experiments and compared with those obtained with the COME-CON chamber (cf. Section 4.1.1.2). Taking the MOD of poly(methyl methacrylate) as unity, the values for all the involved polymers were between 1 and 1.46 in the large compartment and between 1 and 20 in the COMECON chamber. The order of the materials was also different. 

Ascertainment of smoke formation from a material is rather difficult due to the uncertainties in testing and evaluation. The measurement of smoke generation is to some extent dependent on the measurement technique i.e. whether smoke has been collected in a chamber or is streaming in a pipe whether gravimetric or optical evaluation is used and in the case of optical density, whether specific optical density, mass optical density, or a different measure is to be considered. 

Seader, J. D. and Chien, W. P. Mass optical density as a correlating parameter for the NBS density chamber. J. Fire and Flammability, 5, 151 (1974)... 

Most structural methods see either the position of the atomic nucleus (neutron diffraction, NMR spectroscopy), or the atomic center of mass (optical and microwave... 

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