Pr and Nd co-doped Ce-Zr oxide solid solutions (CZPN) were prepared using co-precipitation and microemulsion methods. It is found that only using supercritical CO(2) drying can result in a significant improvement of specific surface area and oxygen storage capacity at lower temperatures for CZPN after aging at 1000°C for 12 h in comparison with those using conventional air drying and even super...

Hydrogenation of various types of oleochemicals is a major unit operation in industry. Natural fatty alcohols are important raw materials for surfactants and lubricants and can be produced by catalytic hydrogenation of fatty acid methyl esters (FAME). Commercial multiphase processes are necessarily operated at high pressures and high hydrogen-to-ester mole ration owing to low solubility of hydr...

Two new concepts have been identified for direct steam generating solar fields that charge a two-tank molten salt storage system. The use of both supercritical and superheated subcritical steam is proposed, and discussed in practical terms and with regards to thermodynamic issues of heat transfer to the salt. Both concepts are found to allow significantly higher hot-tank temperatures than solar...

The effect of alkyl group substituents on the degradation kinetics of poly(alkyl methacrylates) namely poly (n-butyl methacrylate) (PBMA), poly (iso-propyl methacrylate) (PPMA), poly (ethyl methacrylate) (PEMA), and poly (methyl methacrylate) (PMMA) in supercritical and subcritical conditions was studied at various temperatures (250 – 375 o C). The molecular weight distributions were measured b...

Emerging diseases must make a transition from stuttering chains of transmission to sustained chains of transmission, but this critical transition need not coincide with the system becoming supercritical. That is, the introduction of infection to a supercritical system results in a significant fraction of the population becoming infected only with a certain probability. Understanding the waiting...

Several Ge(II) and Ge(IV) compounds were investigated as possible reagents for the electrodeposition of Ge from liquid CH(3)CN and CH(2)F(2) and supercritical CO(2) containing as a co-solvent CH(3)CN (scCO(2)) and supercritical CH(2)F(2) (scCH(2)F(2)). For Ge(II) reagents the most promising results were obtained using [NBu(n)(4)][GeCl(3)]. However the reproducibility was poor and the reduction ...

Supercritical CO2 extraction of the pigments from Bixa orellana seeds was carried out in a flow apparatus at a pressure of 200 bar and a temperature of 40 oC at two fluid flow rates (0.67g/min and 1.12g/min). The efficiency of the extraction was low (only about 1% of the pigment was extracted). The increase in flow rate led to a decrease in pigment recovery. A large increase in recovery (from 1...

The notions of the critical path of events and critical time of an event are key concepts in analyzing the performance of a parallel discrete event simulation. The highest critical time of any event in a simulation is a lower bound on the time it takes to execute a simulation using any conservative simulation mechanism, and is also a lower bound on the time taken by some optimistic methods. How...

The gasification of an aqueous suspension of lignite from Alexandria coalfield (Ukraine) under the supercritical pressure was studied. The initial rates of the formation of hydrogen, carbon dioxide and methane were evaluated. The mutually stimulating interaction of the components of "brown coal-water-mineral matter" system was shown due to the influence of nanoscaled water medium on the formati...

Essential oils have important commercial applications as preservatives and flavours, and more recently as natural antimicrobial agents. These applications require a suitable formulation constituted by biodegradable compounds that protect the essential oil from degradation and evaporation at the same time that allows for a sustained release. Microcapsules of biopolymers loaded with essential oil...