This study presents a literature review of models and methods for dynamic modeling of biped robots with elastic actuators. The adopted workflow consisted of executing search strategies in academic databases (2015–2026) using predefined keywords, and subsequently filtering references based on inclusion criteria such as robot type, employed method/model, research methodology, language, and publication recency. From the final set of 35 articles, relevant information was extracted and synthesized using a bibliographic matrix, comparative tables, and graphs. The results indicate that integrating elastic actuators into biped robots increases design and control complexity; however, it significantly improves locomotion speed, efficiency, motion smoothness, and the ability to emulate biological muscle behavior. Nine models were identified to represent the dynamics of these robots. The robot dynamic model is the most common for evaluating overall dynamic behavior, whereas the SLIP (Spring-Loaded Inverted Pendulum) model is preferred for control-oriented studies due to its lower complexity. In addition, the Euler–Lagrange formulation is most frequently adopted to model the robot, while differential-equation-based models or system identification techniques are typically used for the elastic actuator; nevertheless, methodologies that estimate the full robot dynamics from real data are not ruled out.
This research aims to identify the impact of raw material dimensional quality, as measured by the process capability index corrected for centering (Cpk), on productivity and economic sustainability in the final assembly processes of an industrial maquiladora. A case study was conducted at a company with high levels of waste, downtime, and rework due to out-of-specification components (Cpk < 1.0). The methodology consisted of identifying the poor quality of the raw material that affected the process, quantifying the relationship between raw material quality and productivity, as well as economic sustainability through associated costs, analyzing the lean manufacturing tool, in this case, Total Productive Maintenance (TPM), the implementation of this tool, and the standardization of parameters in order to stabilize the processes. The results show that poor raw material quality increases operating costs and decreases productivity, directly affecting the principles of efficiency and rational use of resources inherent in economic sustainability. After implementing TPM, there was a significant reduction in downtime, unproductive time, and scrap. It is concluded that ensuring raw materials with acceptable Cpk and applying continuous improvement strategies, such as TPM, are key factors in maintaining productive and economically sustainable operations in the long term.
Potato peel is an agro-industrial by-product with potential valorization as a functional ingredient due to its mineral content. However, food use requires demonstrating safety regarding chemical contaminants. This study characterized the essential mineral profile and heavy metals in raw and citric-acid–pretreated potato peel (Solanum tuberosum). Samples were collected in Ambato, Tungurahua, Ecuador, from three parishes (Pasa, Montalvo, and Izamba) and two commercial varieties (Superchola and Única). For each zone × variety combination, a 200 g peel sample was obtained and split into two treatments: raw (single potable-water wash) and pretreated (immersion in 1% w/v food-grade citric acid). Fractions were dried and milled. Essential minerals (Ca, Mg, Cu, Mn, K, Na, Fe, Zn, and P) were determined using a dry ashing approach with AOAC 975.03 as a methodological reference and quantified by atomic absorption spectrophotometry (AAS). Pb and Cd were quantified by AAS following Standard Methods 3111 B (modified), using analytical triplicates. The pretreatment induced zone- and variety-dependent shifts, with recurrent increases in Zn and Fe across several combinations. Cd remained at low levels, whereas Pb persisted at elevated concentrations in both raw and pretreated peels. When contrasted with Codex maximum levels for root and tuber vegetables, Pb emerged as the critical limiting factor for the direct feasibility of a functional ingredient under the evaluated conditions. Despite its favorable mineral potential, potato peel valorization for human consumption requires stricter raw-material control and validated mitigation strategies to reduce Pb to levels compatible with international food safety benchmarks.
The objective of this systematic review is to analyze the main scientific advances related to the use of cellulose extracted from agro-industrial residues for the formulation of biopolymers. To this end, a systematic review of the scientific literature published between 2015 and 2024 was conducted using the Dimensions database, considering studies associated with agroindustrial residues, biomaterials, and biopolymer production methods. The selected studies were evaluated through bibliometric analysis and keyword co-occurrence tools, which enabled the identification of research trends, scientific output, and predominant technological approaches. pp. 33-43 The results indicate that agro-industrial residues constitute an abundant and sustainable source of cellulose, whose valorization promotes the circular economy and reduces environmental impact. Various cellulose extraction methods were identified, including alkaline treatment, acid treatment, bleaching, enzymatic processes, and methods based on green solvents. The latter represents one of the most recent trends and, compared to other methods, yields cellulose with a high degree of purity; however, its main drawback is the high production cost. In this context, acid hydrolysis remains one of the most widely used methods despite involving corrosive reagents. Cellulose extracted from agro-industrial residues is used as a raw material in the production of biopolymers. For the fabrication of biopolymer films, molding is the most commonly employed technique. The main applications of biopolymers derived from agro-industrial residues were identified in the food industry, particularly in food packaging and containers. Overall, the literature demonstrates the growing scientific interest and technological potential of these materials as sustainable alternatives to conventional polymers.
Phytoremediation using aquatic macrophytes is a sustainable strategy for the removal of coliforms and Escherichia coli in wastewater, although its efficiency is subject to variations in environmental parameters such as pH, temperature, and total dissolved solids (TDS). This study developed a first-order kinetic mathematical model, incorporating an environmental penalty mechanism based on a Gaussian function to dynamically adjust the removal coefficient (k) according to physicochemical conditions. Six species of macrophytes (Azolla, Salvinia, Pistia, Ceratopteris, Spirodela, and Eichhornia) were experimentally evaluated alongside a positive control (Lemna) and a negative control (no plant), with daily measurements of bacterial concentrations and environmental parameters over seven days. The results showed that the model adequately described removal trends in several treatments, especially for E. coli. The environmental penalty allowed pH, temperature, and TDS effects on k to be evaluated, producing more conservative predictions. Ceratopteris and Azolla showed the best fits for coliforms (R² > 0.99), while Spirodela, Salvinia, and Eichhornia exhibited low performance. It is concluded that the model is a useful tool for predicting removal efficiency under variable environmental conditions, though further research into species-specific thresholds and microbial variables is required to optimize its applicability in real-world scenarios.
