Organic vehicle removal

Tapes by dip-coating The process is essentially as described in Section 3.6.6. A silver or silver alloy tape is passed through a slurry of the partially reacted Bi-2223 powder dispersed in an organic vehicle. The coated tape is heated at 800 °C in air to remove organics and then at nearly 900 °C when partial melting and controlled recrystallization takes place. 

Barone, M.R. and UUcny, J.C. (1990) Liquid-phase transport during removal of organic vehicle in injection moulded ceramics, J. Am. Ceram. Soc. 73, 3323. 

Evans, J.R.G., Edirisinghe, M.J., WrighL J.K., and Crank, J. (1991) On the removal of organic vehicle from moulded ceramic bodies, Proc. R. Soc. (London) A432, 321. 

To solve the problem of poor adhesion between fiber mats and the substrate, Kim et al. (2006) introduced an additional hot-pressing step after titania fiber deposition. Besides improving adhesion, this treatment was found to have an impact on the microstracture of the fibers as shown in Fig. 2.11. The as-spun metal oxide-polymer composite fibers exhibit a range of diameters from 200 to 500 nm (Fig. 2.11a). When calcined without hot-pressing to remove the organic vehicle, a bundle structure composed of sheaths of 200-500 mn diameters was obtained. In some cases, the outer sheaths were broken, revealing cores filled with 10-nm-thick fibrils as shown in Fig. 2.11c. By introducing the... 

Dielectric paste is a mixture of organic vehicle, glass powders, and oxide powders. Most commonly used ethyl cellulose-based resins are completely removed in air before 550°C. Figure 8.30 is a thermogravimetric analysis of a dielectric paste. The organic removal in the dielectric paste appears to be a two-step process. The weight loss prior to 200°C is associated with solvent removal and that between 250 and 550°C is related to binder removal. 

The former two methods have the considerable advantage that organic vehicle is removed in the liquid state, obviating the need to convert it into large volumes of gaseous product. The former method is particularly attreurtive and has been widely practised for ceramic and metal powders ... 

Many types of defect are produced during removal of the organic vehicle and these have been catalogued The diagnosis of these defects Is not simple. As 1t 1s reheated, the moulded body passes through a region where delayed failure can cause cracking under the Influence of residual... 

Nail polish consists of flexible lacquers, pigments such as organic dyes, iron or chromium oxides, and ultramarine blue along with drying agents and binders or vehicles such as ethyl acetate that evaporate on drying. Nail polish remover is usually an organic solvent such as acetone or ethyl acetate. 

Purified COX-2 (0.79 nmol) is treated with 1.0 mol equivalent of inhibitor and the mixture is incubated for 60 min at room temperature. The remaining activity at this time is 4% that of a vehicle-treated control. The sample is then divided in two and the protein denaturated by treatment with four volumes of ethyl acetate/methanol/1 M citric acid (30 4 1). After extraction and centrifugation (10000 g for 5 min), the organic layer is removed and the extraction repeated. The two organic layers are combined and dried under N2. The extract is dissolved in 10 pi of HPLC solvent mixture consisting of water/acetonitrile/acetic acid (50 41 0.1) and 50 pi are injected onto a Novapak C-18 column (3.9 x 150 mm) and developed at 1 ml/min. The inhibitor is detected by absorption at 260 nm and eluted with a retention time of 6.6 min in this system. Control experiments for inhibitor recovery are performed with incubation of the inhibitor in the absence of enzyme and processing of the samples in an identical fashion before quantitation by HPLC. 

Appreciable interest has been generated in the use of activated carbons for flue gas cleanup, especially for the removal of SOx and NO the adsorption of mercury from flue gases was discussed earlier. From the environmental point of view, emissions from the combustion of fossil fuels in power plants and similar industrial processes are major contributors to a lowering of air quality. The flue ga.ses carry traces of SOi and NO, which can be oxidized and converted to their acid forms in the presence of atmospheric water vapor, and they may also combine with other volatile organics to form ozone and smog. Similarly, low level SOj and NOx emissions from automobiles, while insignificant for individual vehicles, become a large source of pollution when multiplied by the millions of vehicles that are on the roads. 

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