J. F. Sánchez Ramírez

Enhanced of the R6G thermal diffusivity on aggregated small gold particles

R6G dye with gold nanoparticles was prepared in water solution. Using a thermal lens experimental setup, the thermal diffusivity of R6G in presence of gold nanoparticles with Au different concentration was measured. The results show that, the thermal diffusivity of R6G dye mixed with gold nanoparticles increases with the increase of particle metallic concentration, enhancing the thermal diffusivity in the solution. The thermal diffusivity of the samples was studied for a constant concentration of R6G dye 0.1 g/L. The diffusivities were obtained by using the thermal lens aberrant model with lasers arranged in the mismatched mode. The characteristic time constant of the transient thermal lens was obtained by fitting the theoretical expression, for transient thermal lens, to the experimental data. UV-Vis spectroscopy and TEM were used to characterize the R6G dye gold nanoparticles.

Heat Transfer Enhanced in Water Containing TiO2 Nanospheres

In the present work, nanofluids containing spherical TiO2 nanoparticles were mixed in water, to have various concentrations with the average particle diameter of 81.3 nm. Scanning electron microscopy, energy dispersive spectroscopy and X-ray diffraction techniques were used to characterize the TiO2 nanoparticles. Photothermal techniques, thermal lens spectrometry (TLS) and photopyroelectric (PPE) were used to measure the thermal diffusivity and thermal effusivity of the nanofluids respectively. The experimental results show that the thermal diffusivity (D) increased with the increase in TiO2 nanoparticle concentration. It was also possible to see that thermal effusivity (e) had a similar behavior as the thermal diffusivity, where both the values increased with the concentration rate and finally a comparison with literature values show good agreement with the thermal parameters of water.