Coverage confirmation

Coverage confirmation, time to provide full foam coverage, leaks, blockages, rupture disk function, age of foam, portioning calibration mechanisms, performance of delivery pumps or bladder tanks, foam drain times, etc. should be verified for each unique system. NFPA 11 provides guidance in the specific test requirements for several characterisitic foam systems. 

On the basis of the dipole moment, Paik, values computed from the Helmholtz equation (2.21) and the alkali ion radius one can estimate the effective positive charge, q, on the alkali adatom, provided its coordination on the surface is known. Such calculations give q values between 0.4 and 0.9 e (e.g. 0.86e for K on Pt(lll) at low coverages) which indicate that even at very low coverages the alkali adatoms are not fully ionized.6 This is confirmed by rigorous quantum mechanical calculations.27,28... 

In the table, we show the positive SIMS intensities for the above three situations, which were also monitored by XPS for CO coverage and LEED for structural condition. In addition, we also show the intensities for the O.S ML situation where the CO molecule has been deliberately dissociated to C and O atoms by an electron beam. This process was also monitored by XPS, which confirmed that the CO had, indeed, dissociated (from C(ls) and 0(ls) chemical shifts) and that the total coverage was now 0.2S ML (C(ls) and 0(ls) intensities). Several informative points can be gathered from the table ... 

Adzlc et al (25) have shown that partial coverage of the electrode by adsorbed Pb can substantially reduce the effects of poisoning, presumably by blocking the surface sites required by the adsorbed CO. This is nicely confirmed by spectroscopic measurements. Figure 8... 

Structural effect was confirmed by in situ infrared spectroscopy which showed a high coverage of adsorbed CO on a R( 110) plane conversely, on the other single-crystal planes, a distribution of different species is clearly visible. Further, strong lateral interactions between the different adsorbed species on Pt(lOO) lead to very low activity of this electrode at low potentials. ... 

Oudar and co-workers studied the dissociative chemisorption of hydrogen sulfide at Cu(110) surfaces between 1968 and 1971.3,14 As in the case of Ni(110) described below, a series of structures were identified, which in order of increasing sulfur coverage were described as c(2 x 2), p(5 x 2) and p(3 x 2). In contrast to nickel, the formation of the latter phase is kinetically very slow from the decomposition of H2S and could only be produced at high temperatures and pressures. The c(2 x 2) and p(5 x 2) structures were confirmed by LEED,15 17 but the p(3 x 2) phase has not been observed by H2S adsorption since Oudar and colleagues work. 

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