Formation techniques, heat-induced

A wide variety of gel formation conditions and a wide variety of measurement parameters have been used to describe these functional properties, Heat-Induced gel formation techniques generally Involve heating protein dispersions at appropriate concentrations In sealed test tubes (7,13.14.15.16.24.25). In sealed cans... 

Among these various phase separation techniques, pressure-induced phase separation is particularly important since pressure changes can be brought about uniformly and very fast throughout the bulk of a solution. This would not be so in other techniques due to for example heat (in TIPS) and mass transfer (in SIPS) limitations. The technique therefore opens up new opportunities for formation of microstructured materials with potentially more uniform morphologies. It is also important to recognize temperature, solvent, reaction, or field-induced phase separation may all be carried out at elevated pressures if so desired, as such all modes of phase separation methods are of interest when working with near-critical or supercritical fluid systems. 

The simultaneous distillation-extraction (SDE) under atmospheric pressure (53) is not always the most appropriate technique, and its use should be carefully considered. This technique is an elegant and rapid extraction method resulting in an aroma extract that is ready to be injected into a GC system after concentration. However, heat-induced artefact formation, decomposition of labile compounds, and loss of very volatile compounds are serious drawbacks. Furthermore, only steam-distillable volatiles are extracted. Polar compounds, such as hydroxyfura-nones and phenols, are particularly poorly recovered. 

The regeneration of nitroxyl radical from the product of the reaction of nitroxyl radical with the alkyl macroradical was proved in the following experiments [51]. The nitroxyl radical and initiator (dicumyl peroxide) were introduced in a PP powder and this sample was heated to T= 387 K in an argon atmosphere. The concentration of nitroxyl radical was monitored by the EPR technique. The nitroxyl radical was consumed in PP with the rate of free radical generation by the initiator (see Figure 19.3). Dioxygen was introduced in the reactor after the nitroxyl radical was consumed. The generation of peroxyl radicals induced the formation of nitroxyl radicals from the adduct of the nitroxyl radical with the PP macroradical. 

Time-Resolved Laser-Induced Incandescence (by Prof. Alfred Leipertz et al.) introduces an online characterization technique (time-resolved laser-induced incandescence, TIRE-LII) for nano-scaled particles, including measurements of particle size and size distribution, particle mass concentration and specific surface area, with emphasis on carbonaceous particles. Measurements are based on the time-resolved thermal radiation signals from nanoparticles after they have been heated by high-energetic laser pulse up to incandescence or sublimation. The technique has been applied in in situ monitoring soot formation and oxidation in combustion, diesel raw exhaust, carbon black formation, and in metal and metal oxide process control. 

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