Due to the current COVID-19 pandemic, guaranteeing thermal comfort and low CO₂ levels in classrooms through efficient ventilation has become vitally important. This study presents three-dimensional simulations based on computational fluid dynamics of airflow inside an air-conditioned classroom located in Veracruz, Mexico. The analysis included various positions of an air extractor, Reynolds numbers up to 3.5 × 10⁴, four different concentrations of pollutant sources, and three different times of the day. The simulations produced velocity, air temperature, and CO₂ concentrations fields, and we calculated average air temperatures, average CO₂ concentrations, and overall ventilation effectiveness. Our results revealed an optimal extractor position and Reynolds number conducive to thermal comfort and low CO₂ levels due to an adequate ventilation configuration. At high pollutant concentrations, it is necessary to reduce the number of students in the classroom to achieve safe CO₂ levels.

Indoor air conditioning is currently a topic of much interest, not only to save energy but also due to public health issues such as pandemics. This study focuses on the thermal comfort and air quality of a closed, air-conditioned space located in an extremely hot climate. Due to noise and weather conditions, the door and window of the space are kept closed at all times. The study uses computational fluid dynamics techniques and the finite element method. Average temperatures and CO₂ concentrations, as well as effectiveness for temperature and concentration distribution, are calculated for the analysis. Results indicate that supplying air away from hot walls improves air quality and thermal comfort. Furthermore, there is an optimal Reynolds number that depends on the number of people inside the space. Due to the above, it is possible to find an ideal configuration that simultaneously allows for efficient energy use, helps to avoid the adverse effects of CO₂ on daily activities such as working or studying, and supports people’s health and comfort.

The Abandoned Sanitary Landfill of the City of Veracruz, located to the north of the municipality, was built in the year 2000 and operated according to the regulations in force at the time, for a useful life of 10 years. However, it continued its operation irregularly, collapsing and becoming a controlled final disposal site that was closed by the state environmental authorities in 2019. Through the use of Google Earth satellite images using multicriteria techniques, it was determined that it has an area of 167 228 m² and an accumulated volume of waste of 1 505 052 m³. The Mexican Biogas Model 2.0 was used to estimate the generation of biogas that until the year 2023 was a total of 2 898 064 tons of biogas, and with the help of the methodology for the greenhouse effect calculation for urban solid waste, it was determined that in this same period a total of 2 522 057.3 tons of carbon dioxide, 1 162 154.8 tons of methane, and 47 115.9 tons of nitrous oxide were emitted. This represents a total of 47.5 Mt CO2 eq., which underscores the importance of minimizing greenhouse gas emissions and their impact on the environment due to global warming of the atmosphere, especially in the coastal ecosystem where the municipality of Veracruz, Mexico is located.

The Port of Veracruz, Mexico was artificially built at the beginning of the 21st century, dredging the sea floor and removing reefs to allow the entry of large ships, which led to a growth in the traffic of goods and people through it, making it the largest commercial port in all of Mexico. In 1992 the Government of Mexico decreed the area of coastal reefs near the Port of Veracruz as a protected natural area with the name of the Parque Nacional Sistema Arrecifal Veracruzano (PSNSAV). In 2013, with the demand of international trade, the decision was made to expand the port, generating job growth in the area and an increase in the flow of containers and automobiles, also have a greater capacity to transport cereals, minerals and fuels. In contrast to the disagreements of the society due to the loss of protected space, the Parks polygon had to be modified. This work try to demonstrated that the construction of the port expansion began previous the presentation to the environmental authorities of the Environmental Impact Statement and the change in the protected limits with the disappearance of the Punta Gorda reefs and the dredging of Vergara Bay for the arrival of deep draft vessels. Through a systematic mapping of the scientific literature combined with satellite mapping and visual interpretation of images, and documentary analysis, we determined the damage to the reef system, which has protected species according to Mexican national regulations. El Puerto de Veracruz, México fue construido de manera artificial a principios del siglo XXI, dragando el suelo marino y removiendo arrecifes para permitir la entrada de buques de gran tamaño, lo que conllevó a un crecimiento en el tráfico de mercancías y personas a través de él y convirtiéndolo en el mayor puerto comercial de todo México. En 1992 el Gobierno de México decretó en la zona de arrecifes litorales cercanos al Puerto de Veracruz como un área natural protegida con el nombre de Parque Nacional Sistema Arrecifal Veracruzano (PSNSAV). En 2013, con la demanda del comercio internacional, se tomó la decisión de ampliar el puerto, generando un incremento de empleo en la zona y un aumento del flujo de contenedores y automóviles, además de tener una mayor capacidad para transportar cereales, minerales y combustibles. Frente a las disconformidades de la sociedad por la pérdida de espacio protegido, el polígono de Parques tuvo que ser modificado. Con este trabajo se demuestra que la construcción de la ampliación del puerto se inició previa autorización de las autoridades ambientales de la Manifestación de Impacto Ambiental y el cambio en los límites protegidos, lo dicho tuvo inicio con la desaparición de los arrecifes de Punta Gorda y el dragado de la Bahía de Vergara para el arribo de buques de gran calado. A través de un mapeo sistemático de la literatura científica combinado con mapeo satelital e interpretación visual de imágenes, así como el análisis documental, se determinó el daño al sistema de arrecife, el cual cuenta con especies protegidas de acuerdo a la normatividad nacional mexicana.

A compact chemical kinetic mechanism for the combustion of isobutanol (I-C4H9OH), a promising renewable alcohol fuel, is developed in this work. The mechanism is constructed by coupling a small fuel-specific sub-mechanism containing only 11 reactions and 5 additional chemical species to the San Diego combustion mechanism. The resulting reduced scheme preserves the kinetically controlling pathways governing isobutanol oxidation while significantly reducing chemical complexity. The predictive capability of the mechanism is evaluated through comparisons with experimental measurements of laminar flame speeds, ignition delay times obtained in shock tubes and rapid compression machines, and species concentration profiles measured in jet-stirred reactors (JSR) over a wide range of pressures and temperatures. The simulations reproduce the main combustion characteristics with good agreement with experimental data. Heat-release analysis indicates that the competition between aldehyde formation and peroxy-mediated pathways limits the development of strong low-temperature chain branching. Consequently, ignition delay exhibits a monotonic temperature dependence, and no negative temperature coefficient (NTC) behavior is observed under the investigated conditions. Sensitivity analysis confirms that the reactions retained in the reduced scheme correspond to the kinetically controlling processes governing ignition and flame propagation. The resulting mechanism is therefore suitable for combustion simulations, particularly in applications where the use of larger detailed mechanisms becomes computationally demanding for CFD applications.