Global polystyrene (PS) production has been influenced by the lightness and heat resistance this material offers in different applications, such as construction and packaging. However, population growth and the lack of PS recycling lead to a large waste generation, affecting the environment. Pyrolysis has been recognized as an effective recycling method, converting PS waste into valuable products in the chemical industry. The present work addresses a systematic, bibliometric, and statistical analysis of results carried out from 2015 to 2022, making an extensive critique of the most influential operation parameters in the thermo-catalytic pyrolysis of PS and its waste. The systematic study showed that the conversion of PS into a liquid with high aromatic content (84.75% of styrene) can be achieved by pyrolysis. Discussion of PS as fuel is described compared to commercial fuels. In addition, PS favors the production of liquid fuel when subjected to co-pyrolysis with biomass, improving its properties such as viscosity and energy content. A statistical analysis of the data compilation was also discussed, evaluating the influence of temperature, reactor design, and catalysts on product yield.

The use of plastic as material in various applications has been essential in the evolution of the technology industry and human society since 1950. Therefore, their production and waste generation are high due to population growth. Pyrolysis is an effective recycling method for treating plastic waste because it can recover valuable products for the chemical and petrochemical industry. This work addresses the thermal pyrolysis of expanded polystyrene (EPS) post-industrial waste in a semi-batch reactor. The influence of reaction temperature (350–500 °C) and heating rate (4–40 °C min⁻¹) on the liquid conversion yields and physicochemical properties was studied based on a multilevel factorial statistical analysis. In addition, the analysis of the obtaining of mono-aromatics such as styrene, toluene, benzene, ethylbenzene, and α-methyl styrene was performed. Hydrocarbon liquid yields of 76.5–93% were achieved at reaction temperatures between 350 and 450 °C, respectively. Styrene yields reached up to 72% at 450 °C and a heating rate of 25 °C min⁻¹. Finally, the potential application of the products obtained is discussed by proposing the minimization of EPS waste via pyrolysis.

Plastics are essential to technological and industrial development, yet their prevalent single-use life and poor recycling rates are contributing to escalating environmental concerns. Expanded polystyrene (EPS), although valued for being lightweight, durable, and insulating, poses a significant challenge as it is typically disposed of after a single use. Furthermore, traditional recycling is limited because it requires clean, well-separated waste. Therefore, it remains necessary to develop recycling strategies that maximize the value of plastics. To address this issue, the present work aims to provide a comparative evaluation of the synthesis and characterization of FeMg/Al₂O₃ and Fe/Al₂O₃-MgO as catalysts, along with an analysis of their catalytic performance in the pyrolysis of EPS waste at varying temperatures and catalyst loadings. The results showed an advantage in using catalysts in the pyrolysis of EPS waste; however, the FeMg/Al₂O₃ (15 wt.%) catalyst demonstrated the best efficiency in the pyrolysis of EPS waste at 400 °C, achieving 96% liquid yield and reducing reaction times by up to 45% due to its high metal dispersion and strong metal-support interaction, which promotes faster and more efficient conversion. In contrast, Fe/Al₂O₃-MgO showed lower catalytic performance, although it can offer lower synthesis costs and good thermal stability, making it more viable on a large scale. These findings represent a significant advance in catalytic EPS recycling, offering promising strategies to promote the circular economy of EPS and extend its useful life.

Monitoring mechanical vibration is crucial for ensuring the structural integrity and optimal performance of unmanned aerial vehicles (UAVs). This study introduces a portable and low-cost system that enables integrated acquisition and analysis of UAV vibration data in a single step, using a Raspberry Pi 4B, data acquisition (DAQ) through a MCC128 DAQ HAT card, and six accelerometers positioned at strategic structural points. Ground-based engine tests at 2700 RPM allowed vibration data to be recorded under conditions similar to those of real operation. Data was processed with a Kalman filter, a Hann window function application, and frequency analysis via Fast Fourier Transform (FFT). The first and second wing bending natural frequencies were identified at 12.3 Hz and 17.5 Hz, respectively, as well as a significant component around 23 Hz, which is a subharmonic of the propulsion system excitation frequency near 45 Hz. The results indicate that the highest vibration amplitudes are concentrated at the wingtips and near the engine. The proposed system offers an accessible and flexible alternative to commercial equipment, integrating acquisition, processing, and real-time visualization. Moreover, its implementation facilitates the early detection of structural anomalies and improves the reliability and safety of UAVs.

The study of biofuels has become a priority research area in the field of mechanical and energy engineering. One of the most accessible and easily implemented biofuels is biogasoline, a blend of gasoline with a percentage of anhydrous ethanol, generally 10%. This type of blend has been introduced in various countries as a strategy to reduce dependence on petroleum and mitigate emissions of polluting gases. In this project, an experimental study was conducted focusing on analyzing the behavior of a 150 cc, four-stroke internal combustion engine operating with conventional 87-octane gasoline and with bio-gasoline. The results obtained show that the use of bio-gasoline allows for higher engine speeds, with a gain of up to 1000 rpm compared to conventional gasoline. However, the frequency spectra show differences in the high-frequency components, which could be related to changes in the combustion pattern or internal resonances of the system. This project contributes to the understanding of the technical impact of using biofuels in conventional engines and promotes the development of sustainable, accessible energy solutions that are compatible with the existing technological infrastructure.

The energy demand, depletion of fossil fuels, generation of plastic waste, and final disposal of waste cooking oil (WCO) have become major concerns due to industrialization and population growth, creating significant environmental challenges. These challenges have encouraged the development of sustainable alternatives for the valorization of residual feedstocks. On the one hand, global energy consumption continues to increase, promoting the search for alternative fuel sources; on the other hand, the improper disposal of plastic waste has motivated the development of recycling technologies for plastic residues that are difficult to recycle through conventional routes. Moreover, WCO is commonly discharged into drainage systems, contributing to water contamination. Therefore, this study evaluates the alkaline-assisted co-processing of waste cooking oil with crude and distilled expanded polystyrene (EPS) pyrolysis fractions to obtain liquid products with potential application as fuel blendstock components. Specifically, the work explores the co-valorization of WCO with two aromatic hydrocarbon fractions derived from EPS pyrolysis: crude EPS pyrolysis oil and its distillate fraction. These EPS-derived streams are evaluated as residual hydrocarbon co-feeds for the alkaline-assisted processing of WCO into liquid fuel-like products. The influence of the catalyst loading, WCO-to-EPS-derived fraction mass ratio, and EPS-derived fraction type was analyzed based on the liquid product yield. Furthermore, first-generation vegetable oils were tested under selected conditions to compare their behavior with WCO and assess the applicability of the process to different lipid feedstocks. Finally, the fuel-related properties of the obtained liquid products were evaluated through the density, kinematic viscosity, and heating value, and compared with commercial fuel specifications. The results showed liquid product yields up to 92%, kinematic viscosity values within the range of international fuel specifications under selected conditions, and heating values above 40 MJ/kg. However, the density values indicated limitations for direct use as standalone fuels; therefore, the obtained products should be considered as potential fuel blendstock components requiring further blending and chemical characterization studies.