4 research outputs found
Síntesis de una fase de Ba-Ti-Ta a partir de la cristalización controlada de vidrios del sistema BaO-TiO₂-Ta₂O₅-B₂O₃AI₂O₃, para su aplicación en capacitores eléctricos.
Photovoltaic Glass Waste Recycling in the Development of Glass Substrates for Photovoltaic Applications
Because of the increasing demand for photovoltaic energy and the generation of end-of-life
photovoltaic waste forecast, the feasibility to produce glass substrates for photovoltaic application
by recycling photovoltaic glass waste (PVWG) material was analyzed. PVWG was recovered from
photovoltaic house roof panels for developing windows glass substrates; PVWG was used as the main
material mixed with other industrial waste materials (wSG). The glass was casted by air quenching,
annealed, and polished to obtain transparent substrates samples. Fluorine-doped tin oxide (FTO) was
deposited as back contact on the glass substrates by spray pyrolysis. The chemical composition of the
glass materials was evaluated by X-ray fluorescence (XRF), the thermal stability was measured by
differential thermal analysis (DTA) and the transmittance was determined by UV-VIS spectroscopy.
The surface of the glass substrates and the deposited FTO were observed by scanning electron
microscopy (SEM), the amorphous or crystalline state of the specimens were determined by X-ray
diffraction (XRD) and the sheet resistance was evaluated by the four-point probe method. The sheet
resistance of the deposited FTO on the wSG substrate was 7.84 ± 3.11 Ω/, lower than that deposited
on commercial soda-lime glass (8.48 ± 3.67 Ω/), meaning that this material could present improved
conduction of the produced electrons by the photovoltaic effect. This process may represent an
alternative to produce glass substrates from waste materials that could be destined for photovoltaic
applications, especially the production of ecological photovoltaic windows
Effect of Dopant Loading on the Structural and Catalytic Properties of Mn-Doped SrTiO3 Catalysts for Catalytic Soot Combustion
Soot particles have been associated with respiratory diseases and cancer. To decrease these emissions, perovskite-mixed oxides have been proposed due to their thermal stability and redox surface properties. In this work, SrTiO3 doped with different amounts of Mn were synthesized by the hydrothermal method and tested for soot combustion. Results show that at low Mn content, structural distortion, and higher Oads/Olat ratio were observed which was attributed to the high content of Mn3+ in Ti sites. On the other hand, increasing the Mn content led to surface segregation of manganese oxide. All synthesized catalysts showed mesopores in the range of 32–47 nm. In the catalytic combustion of soot, the samples synthesized in this work lowered the combustion temperature by more than 100 °C compared with the uncatalyzed reaction. The sample doped with 1 wt % of Mn showed the best catalytic activity. The activation energy of these samples was also calculated, and the order of decreasing activation energy is as follows: uncatalyzed > Mn0 > Mn8 > Mn4 > Mn1. The best catalytic activity for Mn1 was attributed to its physicochemical properties and the mobility of the oxygen from the bulk to the surface at temperatures higher than 500 °C
Educational Content Development to Enhance STEM Learning
In this study, multidisciplinary teams were formed to develop educational content as digital videos to help in the learning process in Science, Tech-nology, Engineering and Mathematics (STEM) education. The usefulness of the web-learning tool was evaluated by surveys and tests taken by chemical engineering freshman students. The results showed that these students’ scores were higher than the scores obtained by students of previous courses where the web-learning tool was not employed. On the other hand, the au-dience analysis indicated that the average age is 18-24 (91.2%) and the gen-der distribution was 54.9% male and 46.6% female from different countries (Mexico, Colombia, Spain, U.S., among others)