Human–robot collaborative systems have been adopted by manufacturing organizations with the objective of releasing physical workload to the human factor. However, the roles and responsibilities of human operators in these semi-automated systems have not been properly analyzed. This might carry important consequences in the cognitive dimension of ergonomics, which then contradicts the main well-being goals of collaborative work. Therefore, we designed a series of collaborative scenarios where we shifted the assignment of work responsibilities between humans and robots while executing a quality inspection task. Variations in the state of cognitive ergonomics were estimated with subjective and objective techniques via workload tests and physiological responses respectively. Furthermore, we introduced a work design framework based on 50 state-of-the-art applications for a structured implementation of human–robot collaborative systems that contemplates the underlying organizational and technological components necessary to fulfill its basic functionalities. Human operators that possessed responsibility roles over collaborative robots presented better results in terms of cognitive workload and spare mental capacity alike. In this regard, mental demand is seen as a key workload variable to consider when designing collaborative work in current manufacturing settings.

Social programs are crucial to reduce poverty and inequity in developing countries. The operation of social programs, however, cannot be improved with traditional engineering tools since these tools are designed to maximize profits: in social programs maximizing profits is not the objective, social sustainability is. Field research was conducted and it was found that the operation of social programs is considered more socially sustainable if it meets two criteria: Efficiency and Equity; in other words, if the program can help more people who need it the most. This paper proposes a methodology centered in the development of mathematical formulas for the concepts of Efficiency and Equity, so that, by being able to measure them, government programs operation can be enhanced with engineering tools. The methodology is illustrated with a case study, a subsidized milk distribution program in Mexico, called Liconsa. Once the formulas were developed and used in a simulation model for Liconsa, different policies were tested and their results regarding Efficiency and Equity were compared. Results showed the best policies for Liconsa are the balanced ones: where help is increased for beneficiaries, while cost reduction commitments are obtained. In the discussion it is argued how the developed Equity and Efficiency indicators help to understand the tradeoffs between the objectives in opposition: instead of analyzing dozens of indicators, some of them improving and others worsening, the two formulas allow to capture all effects into two objectives and evaluate decisions based on their integral impact. Conclusions show that the mathematical definition of Equity and Efficiency supports better and more informed decision making towards improving the social sustainability of the programs operation. The mathematical definition of Equity and Efficiency and its use in engineering models helps balance the opposing objectives of social programs operation and promotes better and faster changes towards more socially sustainable programs.

In recent years, renewable sources of energy have been sought due to the environmental impacts associated with fossil fuels, such as greenhouse gas emissions into the atmosphere. A promising alternative is biodiesel, particularly when obtained using yeast, as they offer certain advantages over other microorganisms due to their resilience to grow in various conditions, short reproduction times, and lower susceptibility to bacterial infections because they thrive at lower pH levels and have the ability to utilize a wide variety of substrates. Furthermore, biodiesel produced with yeast is composed of methyl ester fatty acids (FAME), providing it with good quality and performance in internal combustion engines, resulting in reduced greenhouse gas emissions compared to conventional diesel. The production of biodiesel using yeast involves six general stages, which offer various methodological alternatives with different degrees of sustainability. The objective of this review is to assess the sustainability degree of various methodologies employed in each of the stages of yeast-based biodiesel production through environmental and economic sustainability indicators.

Purpose: The aim was this study was to test the effectiveness of the Mexican User Satisfaction Index of Circular and Social Economy (MUSI-CSE) methodology to improve user acceptance and the adoption of biodiesel from the Cowichan Bio-Diesel Co-op (CB-DC), a social enterprise that upcycles cooking oil waste. Approach: The external strategy is to study factors of user experience with products and/or services and internal processes. This type of economy tends to build its value chain independently to avoid barriers in the economic structure. Methodology/Techniques: MUSI-CSE presents a model of satisfaction (present acceptance) and loyalty (future acceptance) factors and a measurement system comprising the same factors. It also identifies and monitors interventions in key factors and evaluates their effectiveness. Here, MUSI-CSE has been tested through a longitudinal and prospective study. In-depth interviews, surveys, SEM, and PLS were used. Findings/originality/applicability: User acceptance and adoption are based on self-benefits and the achievement of specific sustainable local development goals. Satisfaction did not change. Loyalty did experience a statistically significant increase at a 95% confidence level, and sales increased by 26%. It can be concluded that MUSI-CSE innovation contributed to improving users’ future acceptance and adoption. In the future, MUSI-CSE will be adjusted based on other case studies and will support the co-creation of an international methodology and index of circular and social economy.