Since the introduction of neoclassical economic theory, material wealth and accumulation have been linked to hedonic wellbeing. In turn, Utilitarian notions have generated the belief that infinite growth is not only good but necessary for society to prosper. Unsurprisingly, this belief system has supported the considerable depletion of natural resources and has not always led to social equitability or environmental justice, two pillars of sustainable development. Given these limitations, this paper looks into eudaimonic wellbeing, as defined by Stoicism. The latter originating in Classical Greece and Ancient Rome, has been used throughout the centuries to discuss and support the flourishing of individuals, but has rarely been applied to collective wellbeing. Consequently, we explore whether, and to what extent, this virtue-based philosophy can answer questions regarding the value and the role of material acquisition in societal development, as directed by sustainable policy. We propose the idea that the Stoic emphasis on prudence, self-control, courage and justice, as the only means to achieve “happiness”, is intrinsically linked to sustainable wellbeing and that its principles can be used to demonstrate that society does not require limitless growth to flourish.

Energy has been at the forefront of the sustainable development discourse for quite some time as policymakers, industry heads and society at large have taken progressive steps to cut carbon via renewable energy technologies and energy efficiency measures. Unfortunately, some of these methods have given rise to perverse socio-environmental effects; as materials have been unnecessarily sacrificed, mines and wells have opened and plantations grown, in the name of energy saving. This paper contributes to clean energy-orientated policies and practices by exploring the discipline of sustainable materials. We first review two strategies: energy efficiency linked to materials; and material efficiency, meaning “doing more with less.” We find that, although both contribute significantly, they are hampered by the rebound effect and their focus on “doing less bad” rather than “good”. Furthermore, they do not in themselves evaluate the services and societal wellbeing that materials provide. We then define “material services” and propose a wider strategy that encompasses and enhances the previous two. Under the new strategy, we argue that sustainable materials should be considered as those that do no harm and which optimally, through the services provided, contribute to better sustainable development policies and practices.

In the vacuum thermoforming process, the group effects of the processing parameters, when related to the minimizing of the product deviations set, have conflicting and non-linear values which make their mathematical modelling complex and multi-objective. Therefore, this work developed models of prediction and optimization using artificial neural networks (ANN), having the processing parameters set as the networks’ inputs and the deviations group as the outputs and, furthermore, an objective function of deviation minimization. For the ANN data, samples were produced in experimental tests of a product standard in polystyrene, through a fractional factorial design (2^k-p). Preliminary computational studies were carried out with various ANN structures and configurations with the test data until reaching satisfactory models and, afterwards, multi-criteria optimization models were developed. The validation tests were developed with the models’ predictions and solutions showed that the estimates for them have prediction errors within the limit of values found in the samples produced. Thus, it was demonstrated that, within certain limits, the ANN models are valid to model the vacuum thermoforming process using multiple parameters for the input and objective, by means of reduced data quantity.

The Exergy Replacement Cost (ERC) is an indicator that is used to ascertain the sustainability of non-renewable resource depletion. Specifically, it measures the amount of exergy society would have to expend if it were forced to re-capture and re-concentrate dispersed minerals back into a manmade usable deposit. Due to an assumption regarding the non-substitutability of fossil fuels, the original method failed to properly account for them. In fact, it sub-estimated their exergy replacement cost forty-seven-fold, on average, when considering solar radiation to fuel, and by approximately fivefold when going from crop to fuel. This new method, via the cumulative exergy consumption (CExC), calculates the exergy replacement cost of photosynthesis and bio-energy production, as together they form the best available technology when it comes to closing the carbon cycle. This approach ties together the “cradle to grave” to the “grave to cradle”, standardises the ERC calculations and enables comparisons between fuel and non-fuel mineral consumption. It also opens a discussion as to the role of the ERC in sustainability debates and whether resource depletion should be a matter of geological patrimony or material/energy services.

This paper is a Colombian case study that calculates the total water footprint (blue, green, and grey) for heavy crude production (11.5 average API gravity) occurring in three fields, located in the Magdalena watershed. In this case study, the highest direct blue footprint registers 0.19 m³/barrel and is heavily influenced by cyclic steam stimulation practices. This value could be reduced if the water coming out of the production well was to be cleaned with highly advanced wastewater treatment technologies. The highest grey water footprint, at 0.06 m³/barrel, is minimal and could be reduced with conventional wastewater treatment technologies and rigorous maintenance procedures. The green water footprint is negligible and cannot be reduced for legal reasons. The indirect blue water footprint is also considerable at 0.19–0.22 m³/barrel and could be reduced if electricity was produced onsite instead of purchased. In addition, the paper identifies methodological flaws in the Colombian National Water Study (2014), which wrongly calculated the direct blue water footprint, leading to a 5 to 32-fold sub-estimation. It also ignored the grey, with important implications for water resource policy and management. To rectify the situation, future National Surveys should follow the procedure published here.