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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

2019

Vol. 26, nr 3

443-453

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.

Examination of the vehicle light intensity in terms of road traffic safety: a case study

Vrábel J., Rievaj V., Synák F., Babic D.

Archiwum Motoryzacji

2018

Vol. 81, nr 3

119--128

Road transport is an essential part of modern life. It brings with itself, besides the desired effects, negative aspects as well. Negative aspect is not only the emissions production but also the traffic accidents occurrence even with tragic consequences. In proportion to traffic intensity, accidents during decreased visibility represent a significant share. A driver has a limited source of information at this time, since only vehicle headlights illuminate the runway and its surroundings. However, these do not only illuminate the roadway ahead of the vehicle, but part of the emitted light also falls into the drivers’ eyes of vehicles in the opposite direction. Thus, the eyes of such glared drivers worse recognize details, or lose the ability to see at all, i.e. vision ability. The level of vision loss depends on the light intensity that falls into the drivers’ eyes in the opposite direction. This light intensity is related not only to the correct headlights alignment (setting) but also to their design. In this paper, three generations of headlights in terms of the light intensity falling into the driver’s eyes of the vehicle in the opposite direction are compared. The headlights alignment of the examined vehicles was checked prior to measurements in accordance with the manufacturer's requirements. Given the fact that intensity of the emitted light is also related to the age of the used source, they have been replaced by the new ones. For the reason of objectivity, examination was performed at night at the New Moon phase, thus it did not light up. The starlight also did not affect the measurement results because it was cloudy, but it did not rain. There were no artificial sources of light near the measuring point.

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

2002

Vol. 50, No. 2

249-258

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.