Mihai Alin Petre

Municipal waste management is a major challenge for sustainable development, as it is strongly influenced by socioeconomic dynamics, seasonality, and the local institutional framework. In this context, this study aims to analyze the seasonality and structure of municipal waste streams at the county level, using monthly operational data provided by the Integrated Waste Management System in Bacău County, Romania. The analysis is based on descriptive statistical methods, seasonal indicators, nonparametric statistical tests, and exploratory multivariate techniques. Seasonal variability was assessed by calculating monthly and seasonal indices, and differences between seasons were tested using the Kruskal–Wallis test. Principal Component Analysis (PCA) and Hierarchical Cluster Analysis (HCA) were used to explore the relationships between waste generation patterns and selected temporal, socioeconomic, calendar, and climatic factors. The results of the analyses reveal a pronounced seasonal pattern, characterized by minimum waste generation during the cold season and maximum generation during the summer months. Residual waste dominates the overall composition throughout the year, while the share of recyclable waste remains low, and the fractional composition remains relatively stable across seasons. Statistical tests confirm the existence of significant seasonal differences between contrasting periods, and multivariate analyses indicate that municipal waste variability is more closely associated with temporal factors and with the socioeconomic indicator considered in this study (average monthly net wage), while climatic variables show weaker associations. From an operational perspective, the results highlight the need to seasonally adjust municipal waste collection, transportation, and treatment capacities, particularly during peak generation periods. By providing a detailed case study at the county level, based on real data, the research contributes to the literature on the seasonality of municipal waste and supports evidence-based management decisions at the local and regional levels, in line with European policy objectives.

This paper develops a generalized kinematic model for a lever-link-type flat pressing mechanism used in food processing applications for compacting the coagulate. The study aims to highlight the influence of the geometric parameter that defines the position of the intermediate coupling on the driving element on the mechanism’s configuration and on the main kinematic variables of the active pressing point. Under an idealized representation—assuming rigid links, perfect joints, and a vertical constraint acting on the active element—general analytical expressions for displacement, velocity, and acceleration were established using the vector-kinematic method. The results show that modifying the position of the intermediate coupling produces nonlinear variations in the length of the connecting element, its spatial orientation, and the vertical motion of the active point. Increased values of this parameter are associated with a greater effective stroke and higher vertical velocities toward the end of the motion, while the calculated accelerations remain relatively low, indicating a smooth kinematic evolution. The model establishes analytical relationships that describe the influence of geometric parameters on the kinematic behavior of the mechanism and can serve as a basis for further developments involving dynamic analysis and experimental validation.