Marco Antonio Zamora-Antuñano

Municipal solid waste (MSW) pyrolysis is a promising route for recovering energy from non-recyclable fractions while reducing landfill volumes, yet most previous studies address waste characterization, kinetics, process simulation, and economic feasibility separately. This study integrates all four dimensions for representative MSW fractions from Guatemala City, combining laboratory-scale slow-pyrolysis experiments, Arrhenius-based kinetic modeling, industrial-scale process simulation, and a discounted-cash-flow economic evaluation, with the resulting kinetic and multivariable yield models demonstrating strong statistical performance, with coefficients of determination ranging from 0.90 to 0.98 based on validation using representative municipal solid waste fractions. Plastic fractions produced the highest bio-oil yields and calorific values, approaching those of fossil fuels, while organic and lignocellulosic fractions favored biochar formation. Multivariable regression models for predicting biofuel yields and calorific values as a function of feedstock chemical composition demonstrated good predictive performance based on the validation statistics obtained. The presence of chlorine and sulfur in co-plasticized materials restricts utilization of bio-oil in combustion engines. Process Simulation has shown that integrating bio-oil refinery into the petrochemical industry is feasible. However, the economic analysis indicated that project viability depends on the successful integration of waste-treatment services with revenues generated from biofuels and energy recovery. These integrated results confirm the technical and economic viability of pyrolysis as a circular-economy waste-management strategy for Central American cities, provided the business model combines a waste-treatment-service component with energy recovery.

Low-temperature proton exchange membrane fuel cells (LT-PEMFCs) constitute a key technology in the context of global energy decarbonization that combines high electrochemical efficiency, low operating temperatures (60–80 °C), and use in transportation, distributed generation, and portable applications. Bipolar plates (BPPs) are the backbone of a fuel cell. They carry out many functions, including electrical conduction, distribution of reactants, thermal management, and mechanical support. BPPs contribute approximately 60–80% to the total system weight and 30–45% to the total system cost. There are many research gaps in BPPs. Previous studies on BPPs are fragmented, and many studies focus on material and geometric design of flow fields, but research on how these factors affect the overall performance of the cell is absent. This segmentation limits the options for developing durable and scalable technological solutions. This review proposes a conceptual approach around three axes: (i) materials and surface engineering (graphite, coated metals, and polymer composites), (ii) flow-field geometry (serpentine, parallel, interdigitated, and bio-inspired), and (iii) operating conditions (temperature, humidity, pressure, stoichiometry, and dynamic regimes). A systematic review of literature published between 2015 and 2025 identified 315 eligible studies, which were retained for qualitative synthesis; from these, 160 representative references were selected for citation based on scientific relevance, methodological rigor, impact, and contribution to the MGOC framework, prioritizing mainly Q1–Q2 publications indexed in Scopus, Web of Science, and ScienceDirect and providing evidence for identifying and elaborating research gaps related to integrated design, multi-objective optimization, and predictive modeling.

Municipal solid waste (MSW) pyrolysis is a promising route for recovering energy from non-recyclable fractions while reducing landfill volumes, yet most previous studies address waste characterization, kinetics, process simulation, and economic feasibility separately. This study integrates all four dimensions for representative MSW fractions from Guatemala City, combining laboratory-scale slow-pyrolysis experiments, Arrhenius-based kinetic modelling, industrial-scale process simulation, and a discounted-cash-flow economic evaluation, with the resulting kinetic and multivariable yield models cross-validated against independent literature data from the Central American region. Plastic fractions produced the highest bio-oil yields and calorific values, approaching those of fossil fuels, while organic and lignocellulosic fractions favored biochar formation. Multivariable regression models for prediction of biofuel yield and calorific value in relation to different chemical constituents of feedstock have produced prediction errors within +/-10%. Presence of chlorine and sulfur in co-plasticized materials restricts utilization of bio-oil in combustion engines. Process Simulation has shown that integrating bio-oil refinery into the petrochemical industry is feasible. However, the economic analysis indicated that project viability depends on the successful integration of waste-treatment services with revenues generated from biofuels and energy recovery. These integrated results confirm the technical and economic viability of pyrolysis as a circular-economy waste management strategy for Central American cities, provided the business model combines a waste-treatment-service component with energy recovery.

Cooking food is a factor that contributes to global energy consumption and greenhouse gas emissions. This research proposes the design, simulation using thermal resistances with MATLAB Simulink, and experimental evaluation of an automated double-concentrated solar cooking system operable from inside a home. Water was used as a cooking load. Each test for 25 min was entered into a system integrated by a programmable elevator to transport the food to the roof, a configurable temperature display, a photovoltaic power source, and double solar collection (direct through a modified box oven and reflected by a parabolic dish collector). When both solar components operated simultaneously, the system reached a temperature of 79 °C, representing a 57.34 °C increase. On average, the solar concentrator provided 78.02% more energy than the oven alone. This approach is expected to reduce cooking time and contribute to sustainable home design aimed at mitigating greenhouse gas emissions.

En este artículo se sugiere aplicar el SMED para mejorar el proceso fabricación de anillos (vane rings) en las líneas de fabricación de una empresa de autopartes en la Ciudad de Querétaro, México. La adaptabilidad de los procesos es crucial para aumentar la productividad, un factor que puede ser una fuente de ventajas competitivas en el mercado. La metodología de estudio implica identificar las máquinas que impactan en la fabricación de Vane Rings, a través de análisis de tiempos perdidos y eficacia; tras identificar las máquinas se determinaron los cambios más importantes y mediante el análisis los resultados se realizó el rediseño del proceso mediante el SMED como la propuesta de valor que sirve de base para mejorar la línea de producción. Existen usos del SMED en diferentes procesos de fabricación, fundición, inyección, troquelado, el objetivo central del presente trabajo fue el rediseño del proceso para la fabricación de Vane Rings, este artículo pretende ser una guía para otras empresas donde la aplicación del SMED podría realizarse de manera igual o similar.

This review explores the historical and current significance of gestures as a universal form of communication with a focus on hand gestures in virtual reality applications. It highlights the evolution of gesture detection systems from the 1990s, which used computer algorithms to find patterns in static images, to the present day where advances in sensor technology, artificial intelligence, and computing power have enabled real-time gesture recognition. The paper emphasizes the role of hand gestures in virtual reality (VR), a field that creates immersive digital experiences through the Ma blending of 3D modeling, sound effects, and sensing technology. This review presents state-of-the-art hardware and software techniques used in hand gesture detection, primarily for VR applications. It discusses the challenges in hand gesture detection, classifies gestures as static and dynamic, and grades their detection difficulty. This paper also reviews the haptic devices used in VR and their advantages and challenges. It provides an overview of the process used in hand gesture acquisition, from inputs and pre-processing to pose detection, for both static and dynamic gestures.

This paper reports on the biosynthesis, characterization, as well as the bactericide and cytotoxic properties of silver nanoparticles supported on bovine bone powder (Ag-NPs/BBP). The silver nanoparticles were obtained through the bioreduction of AgNO₃, using an infusion of Heterotheca inuloides leaves and flowers as a reducing agent and bovine bone powder as a support. The ratio of Ag-NPs/bovine bone powder was set as 1:10. The characterization was performed with SEM–EDS, XRD, UV–Vis, and TEM, which showed the formation of nanoparticles with an average size of 22.6 ± 10.8 nm and a quasi-spherical Ag-NPs morphology supported on the BBP surface. The nanocomposite exhibited a band gap of 2.19 eV. The minimal inhibitory concentration and the minimal bactericidal concentration against S. aureus, E. coli, and S. epidermidis were determined for each strain. In addition, the cytotoxic evaluation of the Ag-NPs/BBP on J774.2 mouse macrophage cells was performed. The Ag-NPs/BBP exhibited a bactericide effect on the strains studied, and the cytotoxicity had a dose-dependent behavior on the cells studied. Therefore, it was found that the ecofriendly synthesized Ag-NPs supported on bovine bone powder resulted in an effective bactericidal system against the strains studied, without significant cytotoxicity.

Jet fuel production is a key element in the aviation industry’s strategy to reduce operating costs and environmental impacts. Alternatives are required, and bioturbosine obtained from biomass can replace significant amounts of jet fuel. In this investigation, the properties of the production of bioturbosine from coconut oil and mixtures of B5, B10, B20, B1OO, bottom, and jet fuel were measured according to the ASTM standards. A transesterification reaction between coconut oil and methanol was carried out using ultrasound, resulting in 99.93% conversion of triglycerides into bioturbosine at room temperature for 10 min, with a 6:1 molar ratio of methanol and oil. The catalyst concentration was 1.0 g/100 g of oil, and purification was carried out without water using an ion-exchange resin to remove impurities. The results obtained for density and viscosity were within the regulations. The temperature of the clogging point for a cold filter in the mixtures was up to −30 °C. The average caloric values of mixtures B5, B10, and B20 were 45,042, 44,546, and 43,611 MJ/Kg, respectively. In a copper corrosion test, the result for all samples was class 1A. It is expected that the results of this research may influence the use of bioturbosine in the aviation industry.