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Comparative review of artificial light sources for solar-thermal biomass conversion research applications

Sobek Szymon, Werle Sebastian

Ecological Chemistry and Engineering. S

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2019

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Vol. 26, nr 3

443-453

EN

In recent years solar-thermal methods of waste biomass conversion are promptly gaining on attention. For researchers working in areas that suffer from lack of natural solar power, the choice of proper solar simulator for the study is crucial. Solar simulator consist of artificial light source enclosed in proper housing with optical and cooling system, powered by dedicated power supply. Solar simulators are not only granting independence from external conditions, yet provide possibility of research expand due to tuneable output power and emissive spectrum. Over the years, solar simulators were powered by different types of lamps. Throughout the history, the solar simulators were used mainly in photovoltaic and space research, crystal growth industry, and the material testing. For mentioned purposes, the total thermal output power of simulator was playing secondary role in comparison to urgent need of spectral match, irradiance distribution and beam uniformity with terrestrial or extra-terrestrial sunlight. For thermal applications, solar simulators are facing the challenge of providing high output power, described by high radiant heat flux and high heat flux density over the specified target area. In presented paper the comparison of xenon arc, metal halide lams and tungsten halogen for thermal applications has been presented with emphasis on available thermal power, spectral match with natural sunlight and operational issues. The course of decision taken during the selection of artificial light source for construction of laboratory-scale solar pyrolytic reactor is proposed.

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Thermal stability of the krypton Hall effect thruster

Szelecka A., Kurzyna J., Bourdain L.

Nukleonika

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2017

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Vol. 62, No. 1

9--15

EN

The Krypton Large IMpulse Thruster (KLIMT) ESA/PECS project, which has been implemented in the Institute of Plasma Physics and Laser Microfusion (IPPLM) and now is approaching its final phase, was aimed at incremental development of a ~500 W class Hall effect thruster (HET). Xenon, predominantly used as a propellant in the state-of-the-art HETs, is extremely expensive. Krypton has been considered as a cheaper alternative since more than fifteen years; however, to the best knowledge of the authors, there has not been a HET model especially designed for this noble gas. To address this issue, KLIMT has been geared towards operation primarily with krypton. During the project, three subsequent prototype versions of the thruster were designed, manufactured and tested, aimed at gradual improvement of each next exemplar. In the current paper, the heat loads in new engine have been discussed. It has been shown that thermal equilibrium of the thruster is gained within the safety limits of the materials used. Extensive testing with both gases was performed to compare KLIMT’s thermal behaviour when supplied with krypton and xenon propellants.

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Modelling the Solubility of Gases in Saturated and Substituted Perfluoroalkanes

Dias A., Pamies J., Vega L., Coutinho J., Marrucho I.

Polish Journal of Chemistry

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2006

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Vol. 80, nr 1

143-152

EN

The importance of the study of fluorinated molecules is justified by the innumerous applications that these compounds are founding in many diverse and interesting areas as a consequence of their unusual properties. They are being used as substitutes for chlorinated solvents, surfactants in supercritical solvents, environmental probes, and in numerous biomedical applications. The choice of the best fluoroalkane to be used for a given application depends on its properties and in some cases, such as in biomedical applications, that choice has to be precise. Thus, the knowledge of the thermodynamic properties of these compounds is of extreme importance as well as the ability to describe and predict them at different conditions using thermodynamic models. In this work, the soft-SAFT EoS is used to describe the solubility of gases as oxygen, xenon and radon in saturated and substituted perfluoroalkanes. The conclusions reached in this work corroborate the experimental evidences reported in the literature indicating that the interaction between the oxygen and the CF3 terminal group is stronger than the interaction between the oxygen and other fluorinated groups in the molecule.

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129Xe NMR of adsorbed xenon and 1H NMR imaging: new methods to study the diffusion of gaseous hydrocarbons in a fixed bed of zeolite

N'Gokoli-Kekele P., Springuel-Huet M.-A., Bonardet J.-L., Dereppe J.-M., Fraissard J.

Bulletin of the Polish Academy of Sciences. Chemistry

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2002

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Vol. 50, No. 2

249-258

EN

129Xe NMR of adsorbed xenon used as a probe and (1)H NMR imaging have been used to study the diffusion of hydrocarbons (benzene, n-hexane, paraxylene) during their adsorption or desorption in a fixed bed of zeolite crystallites. The simulation of experimental (129)Xe spectra using the nonuniform or the shrinking core models gives the concentration profiles of hydrocarbons, in the bed and in the zeolite crystallites, during their adsorption and leads to intracrystalline diffusion coefficients in good agreement with the literature. The (1)H NMR imaging allows one to visualize the progression of the diffusing molecules in the zeolite bed and also to determine their intracrystalline diffusion coefficients in the simplest cases.