Systemic silica associated

Figures 13.4a and 13.4b compare chromatograms published by Heme et al. [23] and chromatograms calculated from the data formd in their paper, assuming Langmuir competitive isotherms (Eq. 13.3) and numerical values of the other parameters that permit the best approximation of the experimental results. In this experiment, a sample containing acetonitrile, N,N-dimethylformamide, ethyl formate, fso-butanol, ethyl acetate and 1-pentanol is eluted on a C18 chemically bonded silica phase (Nucleosil C18), using a water-methanol solution containing 0.00025 M salicylamide, the UV-absorbing additive. The agreement between experimental and calculated chromatograms is excellent. It demonstrates the validity of the theoretical approach. The system peaks associated with the first five components, those that are eluted before the additive system peak (peak 6), are...

The migration of energy between phases will also have an effect in the radiolysis of mixed polymeric systems not associated with transuranic waste. For instance, the radiolysis of polymers attached to silica particles or the radiolysis of rubber in steel belted tires will probably be affected by energy deposited in the non-organic phase. Energy migration to the polymeric phase may lead to the need for lower overall doses than initially anticipated for a... 

Relatively small fractionating volumes are associated with HDC systems. Therefore, the Rf market method (27) typically is used to compensate for possible variations in the operating parameters during the separation. Figure 13 shows a HDC calibration plot that was obtained by the marker method. The arbitrary log sol diameter versus Rf plot produced a linear relationship for this series of 40-600-nm SdFFF-characterized sols as standards. With this particular HDC system, silica sols can be routinely measured with precisions of about 15% (relative) with the peak-position calibration method. This precision level is a direct result of the relatively poor resolution of HDC separations. 

The other problem in water systems is associated with the scaling tendencies of industrial water. The factors governing scale formation are the temperature the rate of heat transfer the calcium, sulfate, magnesium, and silica concentrations the total dissolved solids the pH of the water and the alkalinity in sense of the log and HCOj present. 

Information about the bound water fraction in some colloid systems, silica gels, and biological systems is usually inferred on die basis of the frequency- and time-domain DS measurements from the analysis of the dielectric decrements or die relaxation times (64, 150-152). However, the nonionic microemulsions are characterized by a broad relaxation specfrum as can be seen from the Cole-Cole plot (Fig. 33). Thus, these dielectric methods fail because of the difficulties of deconvoluting die relaxation processes associated widi the relaxations of bound water and surfactant occurring in the same frequency window. 

Orthop Clin North Am 14 675-697 Riidlinger R, Bunney MH, Grab R, et al. (1984) Warts in fish handlers. Br J Dermatol 120 375-381 Rustin MHA, Bull HA, Ziegler V, et al. (1989) Silica exposure and silica-associated systemic sclerosis. Br J Dermatol I2i[suppl 341 29-30... 

Koeger et al. (1995) observed four patients with systemic LE (three with silicosis) and one with discoid LE among 24 cases of silica-associated CTD. 

Rustin MHA, Ziegler V, Mehlhorn L, et al. (1990) Silica associated systemic sclerosis is clinically, serologically and immunologically indistinguishable from idiopathic systemic sclerosis. Br J Dermatol 123.725-734... 

As pointed out earlier (Section 3.5), certain shapes of hysteresis loops are associated with specific pore structures. Thus, type HI loops are often obtained with agglomerates or compacts of spheroidal particles of fairly uniform size and array. Some corpuscular systems (e.g. certain silica gels) tend to give H2 loops, but in these cases the distribution of pore size and shape is not well defined. Types H3 and H4 have been obtained with adsorbents having slit-shaped pores or plate-like particles (in the case of H3). The Type I isotherm character associated with H4 is, of course, indicative of microporosity. 

Water occurs in glass-ionomer and related cements in at least two different states (Wilson McLean, 1988 Prosser Wilson, 1979). These states have been classified as evaporable and non-evaporable, depending on whether the water can be removed by vacuum desiccation over silica gel or whether it remains firmly bound in the cement when subjected to such treatment (Wilson Crisp, 1975). The alternative descriptions loosely bound and tightly bound have also been applied to these different states of water combination. In the glass-poly(acrylic acid) system the evaporable water is up to 5 % by weight of the total cement, while the bound water is 18-28 % (Prosser Wilson, 1979). This amount of tightly bound water is equivalent to five or six molecules of water for each acid group and associated metal cation. Hence at least ten molecules of water are involved in the hydration of each coordinated metal ion at a carboxylate site. 

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