Browsing by Author "González Hormazábal, Marcelo Andrés"

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    A Novel Offsite Construction Method for Social Housing in Emerging Economies for Low Cost and Reduced Environmental Impact
    (MDPI, 2023) Tapia Reed, Danilo Alejandro; González Hormazábal, Marcelo Andrés; Vera Araya, Sergio Eduardo; Aguilar, Carlos
    Offsite construction methods have shown many advantages over traditional construction techniques, especially related to efficiency and productivity during the construction phase. Nevertheless, offsite construction generally involves oversizing the internal structure of the modules due to the internal stresses produced during transport and lifting operations, producing an increase in material usage, direct cost, and carbon footprint. In developing countries, the direct cost of social housing is the most important factor determining the feasibility of construction. For this reason, oversizing the internal structure of the modules can play an important role in the adoption of a modern construction technique such as offsite construction systems. In order to solve this issue, a temporary reusable stiffener structure is proposed to allow an economical offsite construction system using a lightweight steel framing structure used in traditional methods. The reusable structure was designed using a finite element method, and the direct cost and carbon footprint of the structure were evaluated. The results show that the proposed construction strategy allows for a low cost and reduced environmental impact due to a lower usage of materials in the modules and the possibility of a circular economy approach to the reusable structure.
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    Effects of two chemical treatments on the optical properties of the rutile crystalline phase.Efectos de dos tratamientos químicos sobre las propiedades ópticas de la fase cristalina de rutilo
    (2022) Retamoso Llamas Claudia Patricia; Escalona Burgos, Néstor Guillermo; González Hormazábal, Marcelo Andrés; Barrientos Poblete, Lorena Julieta
    © 2022, Universidad de Los Andes. All rights reserved.The optical properties of the photocata-lysts are related to the band gap since it impacts the results of contaminant removal effectiveness during irradiation. Among the photocatalysts, anatase has been studied more than rutile. In the present work, chemical treatments were carried out on rutile to shift the band gap towards the visible zone of the electromagnetic spectrum. The results suggest that the incipient impregnation with Fe salts effectively shifts the energy gap to the visible area, significantly decreasing the maximum absorbance levels. While the partial reduction of rutile increases the absorbance levels when carried out at a temperature of 250 °C.
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    Exploration of the initial photocatalytic activity parameters of ?Fe2O3–rutile for methylene blue discoloration in water through the OFAT process
    (2023) Retamoso Llamas, Claudia Patricia; Escalona Burgos, Néstor Guillermo; González Hormazábal, Marcelo Andrés; Barrientos Poblete, Lorena Julieta
    The photocatalyst response is related to experimental conditions that improve effectiveness in removing contaminants. A parameter analysis of ?Fe2O3–rutile and water contaminated with methylene blue (MB) was carried out to obtain initial factors that impact reaction conditions. Moreover, the following factors were tested: the ?Fe2O3–rutile load, the initial MB concentration, and the initial pH solution. These one-factor-at-a-time variations were made to explore the conditions of each variable with the other two fixed. Above all, a significant change was identified in the initial discoloration rate from 5.2 to 35.56 10?9 mol g?1 s?1, with 34 and 91 % removal effectiveness, respectively. These results were achieved with an ?Fe2O3–rutile load of 1.0 g L?1, an initial MB concentration of 8.0 10?6 mol L?1, and a pH of 8.8, after 540 min of irradiation. This high discoloration effectiveness with ?Fe2O3–rutile had not been previously reported. The parameter that most influenced the photocatalytic activity was the initial pH solution due to the interaction of the point of zero charge of ?Fe2O3–rutile and the contaminated water; the pH of the solution exceeds the isoelectric point, it causes electrostatic forces and hydrogen bonds with MB to increase its effectiveness. The combination of ?Fe2O3–rutile and the removal of methylene blue in water improves adsorption on the surface of the ?Fe2O3–rutile, providing the highest discoloration rate.
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    High-performance and low-cost electrochemical reactor for limestone decarbonation applied to clinker production – A validation at laboratory scale
    (2024) Martínez, Natalia P.; Troncoso P., Felipe; Gazzano, Valeria; Ramírez Amaya, Darío Alonso; González Hormazábal, Marcelo Andrés; Navarrete Leschot, Iván Ignacio; Canales Muñoz, Roberto; Dreyse, Paulina
    Limestone decarbonation to obtain CaO (calcium oxide) and produce cement is an industrial activity with enormous CO2 emissions, due to the intrinsic calcination reaction of CaCO3 (calcium carbonate), in addition to the use of fossil fuels. One of the most recent ideas to reduce CO2 emissions in this process has been the electrochemical decarbonation of limestone where Ca(OH)2 (calcium hydroxide) is obtained as an intermediate product that is then used as CaO precursor in clinker synthesis. This study shows the design of a low-cost electrochemical reactor and the optimization of the parameters to produce Ca(OH)2 with high purity and yield from the decarbonation processes of pure CaCO3 and limestone used in the cement industry. In addition, the remaining limestone sludge and electrolytic solutions were analyzed, and it was found that the sludge can be used as a correction material in clinker preparation, and it is also possible to reuse the electrolytic solution twice. Finally, the main finding is the proposal of a new clinker synthesis, which results in a cement with comparable characteristics to those of ordinary Portland cement, using Ca(OH)2 obtained from the electrochemical decarbonation of CaCO3, achieving a reduction in CO2 emissions of approximately 90% compared to the conventional method.