Publications by authors named "Gustavo Goncalves Dalkiranis"

Article Synopsis
  • Ultraviolet light-emitting diodes (UV-LEDs) are a promising alternative to traditional mercury lamps for disinfecting water by inactivating microorganisms.
  • This study specifically examined the effectiveness of a bench-scale UVC-LED system at 280 nm on various pathogens, including E. coli, PhiX-174, MS2, and Cryptosporidium oocysts, under different water qualities.
  • Results showed that while microbiological reductions varied with exposure time and water quality, UVC-LED technology was generally effective in achieving significant reductions of bacteria and viruses, highlighting its potential for use in small water systems as recommended by the World Health Organization.
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A novel spectroscopic technique, photoluminescent ellipsometric circular dichroism (PECD), which distinguishes all radiative electronic transitions related to molecular chiral centers. Additionally, it is proposed as complementary to the ellipsometric Raman spectroscopy (ERS) technique, thus establishing a relationship between vibrational modes and electronic transitions, associated with molecular chiral centers. In this way, PECD turns into a powerful technique for chiral material characterization.

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Thermoelectricity (TE) is proving to be a promising way to harvest energy for small applications and to produce a new range of thermal sensors. Recently, several thermoelectric generators (TEGs) based on nanomaterials have been developed, outperforming the efficiencies of many previous bulk generators. Here, we presented the thermoelectric characterization at different temperatures (from 50 to 350 K) of the Si thin-film based on Phosphorous (n) and Boron (p) doped thermocouples that conform to a planar micro TEG.

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Ultrathin Si films have a reduced thermal conductivity in comparison to Si bulk due to phonon scattering at the surfaces. Furthermore, the small thickness guarantees a reduced thermal mass (in the µJ/K range), which opens up the possibility of developing thermal sensors with a high sensitivity. Based on these premises, a thermoelectric (TE) microsensor based on ultrathin suspended Si films was developed and used as a thermal photosensor.

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