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The environmental performance of additive manufacturing (AM) processes and the produced parts has gained increasing interest. Various assessment models have been developed based on the general life cycle assessment (LCA) framework, although different in goals and boundaries, the inputs for these models are always a single part (or a batch of same parts). In contrast, the present research provides a new perspective towards the selection of a more sustainable assembly design. A comparative LCA model is built to investigate the environmental performance difference of two design approaches: assembly design (AD) made via conventional manufacturing (CM) plus assembly operations and part consolidation (PC) made via AM plus machining. The effects of weight reduction, prolonged life expectancy, and improved functional performance (e.g. fuel efficiency) attainable in the PC routine and the advantages of replaceable subcomponents in the AD routine are studied in a throttle pedal assembly example throughout the lifespan of the vehicle. The results reveal that the PC routine can be more environmental friendly than the AD counterpart when the lifespan can be improved by over 200% or the weight savings are more than 30%. The role of functional performance improvement on affecting sustainability may depend on the part/vehicle ratio and vehicle types. This article extends the literature on sustainable assembly design and the proposed LCA model provides a way of identifying the profitable margins of PC in the early design stage. • A comparative LCA model is built for consolidated design and assembly design. • Factors of lightweight, lifespan extension, performance increase, and part reuse are considered. • Tradeoffs between the consolidated design and assembly are discussed through a case study. • Design guidelines to select a more sustainable assembly design solution are proposed. [ABSTRACT FROM AUTHOR]

Additive manufacturing, also known as 3D printing, is acknowledged for its potential to support sustainable design. In this paper, we explore whether the opportunities that additive manufacturing offers for sustainable design are also useful when designing for a circular economy, and to what extent additive manufacturing can support design for a circular economy. We performed a literature review on the sustainability aspects of additive manufacturing and held a series of interviews with designers about their 3D printed design projects to obtain in-depth information. The interviews were analysed using annotated portfolios, a novel analysis method created specifically for this research. This resulted in a visual representation of the outcomes. We found that additive manufacturing supports circular design strategies by creating opportunities to extend a product's lifespan, for instance by enabling repair or upgrades, even if these products were not originally designed for ease of repair or upgrading. However, the use of monolithic structurally complex parts that support design for recyclability may hinder high value product recovery, like repair. Besides this, the current offer of 3D printable materials should be extended with materials developed for durable use, as well as high-value reuse. Concluding, when accounting for these drawbacks, additive manufacturing is able to support multiple product life cycles and can provide valuable contributions to a circular economy. • Additive manufacturing creates opportunities for applying circular design strategies. • Sustainable additive manufacturing opportunities should support multiple product lifecycles. • Availability of sustainable materials for additive manufacturing is an issue. • The interview data were analysed with annotated portfolios, a newly developed method. [ABSTRACT FROM AUTHOR]

Abstract Road pavement community members are increasingly becoming aware of the need to incorporating the principles of sustainable development into the sector. Policies are also going in this direction and as a consequence in the recent years researchers and practitioners are coming up with new materials, technologies and practices designed to reduce the negative impacts of their activities in the surroundings. Within this framework the road pavements sector is witnessing a paradigm shift towards the development of pavement technologies incorporating high-content of recycled materials, as well as best practices to decrease the overall carbon footprint. These are all promising solutions that to the most can sound as sustainable practices. However the whole road pavement community is still investigating methodologies and tools to define what actually sustainable means and thereby performing a sustainable decision-making. It is within this context that the need of a sustainability-based decision support system (DSS) that could help road pavement engineers at the design stage was identified and is here presented. The Sustainable Pavements & Railways DSS (SUP&R DSS) relies on a multi-criteria decision analysis (MCDA) method to rank the sustainability of alternatives. It applies life cycle-based approaches to quantify the values of a set of indicators purposely and methodologically selected to capture the cause-effect link between the general concepts of the three wellbeing dimensions of sustainability, i.e., environmental, economic and social, and the infrastructure construction and maintenance practice. Furthermore, the system allows selecting different weighting for the indicators but offers also a default set of values derived from a survey conducted with over 50 stakeholders in Europe and beyond. Together with the development, structure and features of the SUP&R DSS, this paper present its applicability by means of a case study aiming at identifying the most sustainable asphalt mixture for wearing courses. Several promising options for flexible road pavements were selected, ranging from low to hot temperature asphalt. The results show that a foamed warm mix asphalt mixture with a reclaimed asphalt pavement content of 50% is the most sustainable among the competing alternatives. Furthermore, a sensitivity analysis conducted to investigate the influence of the indicators weights, the parameters of the MCDA method and the long-term performance of the alternative asphalt mixtures on the stability of the ranking showed that its first position in the ranking remained unaffected. Graphical abstract Image Highlights • A sustainability-based decision support system for road pavements is proposed. • The SUP&R DSS relies on a multi-criteria decision analysis method. • Several types of asphalt mixture for wearing courses were ranked. • A foamed WMA mixture with a RAP content of 50% is the most sustainable. • The ranking remained unaffected after changes in the indicators weights values. [ABSTRACT FROM AUTHOR]

Although UNESCO and the UN's Sustainable Development Goals have articulated the critical role of engineering in achieving sustainable forms of development, there remains the need to analyze the design, features, and nature of sustainability-focused initiatives in engineering education. To date, few studies have identified the main knowledge gaps in this sector of higher education. At the same time, there is no known research exploring student and graduate learning outcomes in particular contextual settings. To address these gaps, this article uses a realist scoping review to map and analyze how engineering education has approached sustainability in higher education institutions since the 1990s. Our study explores the approaches of curricula, teaching, and learning renewals promoted in higher education engineering programs identifying critical differences between the expected and actual learning outcomes. Key findings drawn from a range of international contexts include broad evidence that engineering education providers desire to approach sustainability from an integrative perspective. However, this approach typically demands more administrative resources to develop formal and hidden curriculum mechanisms. As a result, engineering education struggles to foster the associated intra- and inter-cultural learning characteristics expected within integrated sustainability education. Findings also suggest re-evaluating the connotation and senses of 'being and becoming an engineer', including social responsibilities in engineering education, to empower students as active agents of change. Implications for practice, policy, and curriculum development of nine approaches to engineering education for sustainability are also offered, alongside possibilities and priorities for future research. [Display omitted] • Shows how scoping reviews can enrich research on higher education for sustainability. • Identifies nine approaches to how engineering education has approached sustainability. • Discusses key mechanisms and contextual factors for each of the nine approaches. • Finds the 'triple bottom line' is prevalent and directed towards economic progress. • Illustrates why cultural perspectives need engaging to support sustainability goals. [ABSTRACT FROM AUTHOR]

Abstract: This paper originated as a part of a comprehensive research project designed to develop ecologically sustainable, environmentally friendly, resource- and energy-saving industrial process technology for the production of a wide class of phosphorus containing substances. The essential feature of the research was designed for the replacement of tubular heat exchangers with Plate heat exchangers (PHEs) and for the installation of these units in new locations in the processes to optimally improve energy efficiency and to prevent pollution. Despite the severe operating conditions in the production of phosphoric acid PHEs of various designs find the application in these processes. For such a corrosive environment as a phosphoric acid production plant, the Hastelloy G30 alloy is used as the material for the plates and synthetic rubber EPDM is used as the material for inter-plate gaskets. The analysis of the data shows, that using mixed groupings of plates in the unit allows one to obtain optimal solutions. The simulation of barometric mixing condenser recycled water cooling with plate heat exchanger shows the possibility of an application which minimizes the waste water pollution by closing the condenser cooling water circuit. Software was developed for calculations of units working both with liquid and phase changing streams. [Copyright &y& Elsevier]

The increasing population and continuous urbanization make food security prominent in sustainable development. It is important to develop economic and resource-efficient farming solutions to meet food demand. Renewable energy and waste valorization may bring benefits to build sustainable food production systems and facilitate circular economy. This work aims to develop a decision support framework for the stakeholders to quantitatively assess and optimize their urban farming systems for efficient investment and operation. The proposed framework is based on a holistic system model that considers the energy and material consumption in vegetable production processes and the economic and environmental performance of urban farming systems. In the multi-dimensional assessment model, the net present value and cradle-to-gate CO 2 emission, water consumption, and land occupation of different configurations of urban farming systems were assessed. In a further development, the assessment model was embedded in an optimization framework to identify the optimal system design and operation. The optimal crop mix and the corresponding cultivation set points (such as temperature, humidity, irradiance, illumination time, and CO 2 concentration) for the farming modules were determined via optimization. To demonstrate the proposed framework, a case study on the design and operation of a vertical farm in Singapore was carried out. The case study examined alternative farming systems with glass-enclosed vs window-free structural design, grid vs solar photovoltaic (PV) energy supply, and traditional chemical fertilizers vs food waste compost fertilization. Results showed that plant-factory farming systems integrated with solar PV and beer-residue-derived fertilizer could be a promising and sustainable farming solution for Singapore as a tropical megacity. Image 1 • A framework is developed for the design and operation of urban farming systems (UFS). • UFS are analyzed economically and environmentally via modeling, LCA and optimization. • The optimum crops and operating conditions for a case study in Singapore are found. • Plant factories are more energy efficient than glass greenhouses in tropical weather. • Solar PV and waste-to-fertilizer are economic and sustainable means to run UFS. [ABSTRACT FROM AUTHOR]

This research provides insights into how sustainability considerations in engineering product design can be addressed through early stages of requirement management processes. Five key elements for successful implementation of sustainable product development from a requirement management perspective are presented, demonstrating how organisational sustainability maturity can be linked to the design and structure of a company's operational management system. Through a thematic analysis of fifteen interviews with representatives from seven Swedish product developing-and manufacturing companies, critical activities and roles, examples of methods and tools utilisation and implementation, together with challenges and opportunities were identified. This empirical data was used to develop, test and refine a model in which key characteristics of sustainable product design and engineering design were coupled, resulting in a profile model for management of sustainability in requirements. Product developing companies can use the profile model as guidance towards necessary actions that enhance organisational sustainability maturity. Motivated by a low uptake rate of sustainability design tools in industry, this study brings attention to organisational capabilities for successful implementation of sustainable product development. As a lack of traceability is a potential cause, strategic socioecological contextualisation of needs is suggested to improve the chain of decision making in engineering design projects. The guiding research question was ' What are sustainability requirements and how are they identified and managed in design projects? '. The main contribution is a proposed conceptualised model that aims to support design teams to identify and manage sustainability in requirements for engineering design projects. Future studies will test and validate the model. • Profile model for sustainability integration in engineering design requirements is proposed. • Sustainability maturity of product innovation processes linked to requirements traceability. • Five key elements of early requirements management and sustainability maturity are presented. • Challenges and opportunities to sustainability integration in requirements shared. • Model and case-study guides industry- and research actions towards sustainability maturity. [ABSTRACT FROM AUTHOR]

Achieving sustainability in product life cycle involves the complex decision making process such as the selection of conceptual schemes and manufacturing processes, and disposing method of end-of-life. Morphological matrix is simple and useful tool for mapping design requirements in conceptual design for new product design and redesign of out-of-date product. Although conceptual design using morphological matrix as an important step in the product development could achieve sustainability requirements through accurate choice, quantitative decision making method is seldom considered in selection of function solution principle for sustainability. Meanwhile, uncertainties of sustainability attributes in conceptual stage generally are not also considered in these morphological matrix. To solve these problems, this paper put forward an approach based on morphological matrix to satisfy sustainability requirements in product conceptual stage considering vagueness and uncertainty through intuitionistic fuzzy number. The aim of this paper is to quantify conceptual schemes considering sustainability attributes using group decision making and intuitionistic fuzzy preference relations. The decision makers' weights are calculated based on theirs experiences and knowledge on the function, manufacturing, economic, environment, recycle and social properties of product. The morphological matrix is used to establish the relationship between function and solution principles based on sustainability information, then the preference degree are obtained from multiple experts employing intuitionistic fuzzy judgment matrix. The preference degree for each solution principle is quantified by intuitionistic fuzzy numbers through membership, non-membership and hesitancy degree to express the linguistic terminology. To ensure the consistency and consensus issues of preference relations, an additive consistency method is employed, and correction factor is used for achieving modification automatically of judgment matrix when the consistency requirement is not met. Finally, the integrated multi-criteria decision model for function solution principle is established to carry out the final sustainability decision problem in early design stage. The feasibility and validity of proposed method is proved through a practical example for spindle system design of CNC. [ABSTRACT FROM AUTHOR]