Teachers in schools often face working conditions imposed by educational institutions that can pose ergonomic risks and affect their health. This research aims to determine the presence of musculoskeletal disorders and the ergonomic risk factors associated with this population. We collected anthropometric data, assessed musculoskeletal symptoms using the Nordic Kuorinka questionnaire in 134 teachers, and analyzed their workplaces using the ERGO/IBV software. The results include an anthropometric description, highlighting that 94% of women and 87% of men are overweight or obese. It also shows the presence of musculoskeletal discomfort, with 69% and 49% of teachers reporting neck and back/lumbar pain, respectively. Among the main attributions to these discomforts, teachers mention that repetitive tasks, improper postures, and stress are the causes. Finally, the results of the ergonomic assessment are mentioned. Using the rapid entire body assessment method, a high and very high risk level was identified for each subtask, while in respect to repetitive tasks, the neck was identified as the most critical area due to the activities performed. In conclusion, we found an association between back/lumbar pain and body mass index, suggesting that overweight or obesity may increase the risk of musculoskeletal disorders. Additionally, cervical pain is directly related to the repetitive tasks performed by teachers.

This study aimed to investigate the sustainable use of recycled plastics, specifically polypropylene (PP) and high-density polyethylene (HDPE), in the manufacture of geogrids for geotechnical and civil engineering applications. Plastics were collected from a recycling center, specifically targeting containers used for food, cleaning products, and other domestic packaging items. These plastics were sorted according to the Möbius triangle classification system, with HDPE (#2) and PP (#5) being the primary categories of interest. The research methodologically evaluates the mechanical properties of PP/HDPE (0/100, 25/75, 50/50, 75/25 and 100/0% w/w) composites through tensile and flexural tests, exploring various compositions and configurations of geogrids. The results highlight the superiority of pure recycled HDPE processed into 1.3 mm thick laminated yarns and hot air welded for 20 to 30 s, exhibiting a deformation exceeding 60% in comparison to the PP/HDPE composites. Through SolidWorks^® Simulation, it was shown that the adoption of a trigonal geogrid geometry optimizes force distribution and tensile strength, significantly improving slope stabilization efficiency. Based on the results obtained, a laboratory-scale prototype geogrid was developed using an extrusion process. The results underscore the importance of careful composite design and yarn configuration selection to achieve the desired mechanical properties and performance in geogrid applications. It emphasizes the potential of recycled plastics as a viable and environmentally friendly solution for stabilizing slopes, contributing to the reduction in plastic waste and promoting sustainable construction practices.

Hydropower-dominated electricity systems are increasingly exposed to hydroclimatic variability, making anticipatory streamflow information essential for energy security, operational resilience, and sustainable planning. This study develops a transparent monthly early-warning framework for the Paute River basin, Ecuador, a strategically important hydrological system for national hydropower generation. Using a 42-year series of observed and compiled monthly streamflow records from 1984 to 2025 (n = 504), the framework derives seasonal low-flow thresholds (P20 warning and P10 critical) and fits a Seasonal Autoregressive Integrated Moving Average model to log-transformed flows. The resulting lognormal predictive distribution provides point forecasts, prediction intervals, and probabilities of low-flow events. Predictive skill was assessed through a 2016–2025 rolling-origin validation with 120 one-step-ahead forecasts and benchmarks against Error–Trend–Seasonal Holt–Winters and seasonal naive models. The SARIMA-log specification achieved the best point accuracy (MAE = 38.80 m³/s, RMSE = 47.62 m³/s, sMAPE = 32.63%) and modest but useful probabilistic skill (CRPSS = 0.069; Brier Skill Score = 0.169 for Q < P20 and 0.274 for Q < P10). A threshold-sensitivity analysis showed that the 0.15 and 0.30 alert thresholds represent a deliberate trade-off between early detection and false-alarm reduction. For 2026, August displayed the highest low-flow probability (P(Q < P20) = 0.303), triggering a moderate Hydropower Low-Flow Risk Traffic-Light category. The contribution is not a new forecasting algorithm but an operationally auditable integration of seasonal thresholds, probabilistic forecasting, verification, and risk communication for hydropower energy-security governance in the tropical Andes.

Mechanical recycling of post-consumer poly(ethylene terephthalate)/high-density polyethylene (PET/HDPE) streams is limited by immiscibility and processing-sensitive behavior. A nominal 30 wt% PET/70 wt% HDPE blend was evaluated using a 2 × 3 factorial matrix combining maximum extrusion setpoints (T_e: 235 and 260 °C) and maximum injection setpoints (T_inj: 200, 230, and 260 °C). Each processing combination was represented by one run from common bulk feedstocks. Tensile (n = 54) and flexural (n = 53) responses were compared using within-campaign specimen-level contrasts and descriptive multi-response scoring. The T_e= 260 °C/T_inj= 200 °C condition produced the highest observed strength–stiffness response, with tensile strength of 32.5 ± 2.23 MPa, flexural strength of 49.2 ± 6.35 MPa, and flexural modulus of 1550 ± 143 MPa. At T_inj= 200 °C, phase-agnostic SEM analysis showed finer fracture-surface texture after extrusion at 260 °C. Charpy impact followed a different trend, with T_e= 235 °C/T_inj= 200 °C giving the highest observed blend impact response. These results indicate distinct processing–performance relationships for static and impact behavior in the uncompatibilized post-consumer PET/HDPE blend and establish a baseline for further processing and compatibilization studies.