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The time and heat flux required for the initiation of smoldering combustion in cellulosic fabrics depends on the properties of both the environment and the fabric. In the environment, there must be sufficient oxygen to support smoldering combustion and there must be sufficient heat to raise the temperature of the fabric to the point where combustion becomes self supporting. The critical factors for the cellulosic fabrics are the potassium and/or sodium ion content and the thermal characteristics of the fabric. A series of simple weave, raw cotton fabrics, commonly referred to as cotton ducks, and an upholstery fabric were examined. The requirements for the initiation of smoldering combustion were similar for both the ducks and the upholstery fabric. However, the situation for the upholstery fabric was complicated by the non-homogeneous distribution of ions in the material and spatial variations in fabric thickness and basis weight. Also, for fabrics with potassium and sodium ion contents in the range of approximately 1500 to 2500 ppm, there was an increased sensitivity to the environmental factors.

The effect of solution pH and supporting electrolyte anion on the SERS behavior of cyanide species adsorbed at Ag electrodes is described. Signals for the p(CN) are observed in both acidic (pH 2) and basic (pH 11) media in C104", Cl-, and S042supporting electrolytes. The frequency and intensity of the i/(CN) band are a function of electrode potential in all media. The potential at which the SERS signal reaches a maximum intensity is slightly dependent on the anion of the supporting electrolyte in basic media, but is a strong function of the anion in acidic media. In acid solution, HCN is adsorbed. Two unresolved bands occur in the v(CN) region in acidic media and several possible assignments are proposed. The assignment that best explains all of the experimental data involves both end-bonded and side-bonded HCN. The effect of supporting electrolyte anion on the SERS response is explained in terms of the relative abilities of these anions to influence the self-association of HCN in the interface.

The surface-enhanced Raman scattering (SERS) behavior of HCN at polycrystalline Ag electrodes modified by monolayer and submonolayer amounts of underpotentially deposited Pb is presented. Changes in SERS intensity as a function of Pb coverage are interpreted in terms of preferential displacement of HCN from active sites by deposited Pb. By comparison with previous results obtained with pyridine and Cl™ as adsorbates in similar experiments, these data suggest that both large-scale and atomic-scale roughness features contribute significantly to the SERS intensities measured in these systems.