DISCUSSION: THE EXTENSION OF SYSTEM BOUNDARIES IN SHIP DESIGN

This paper is to be welcomed as it argues for the broadening of ship design from what has generally been too narrow a focus in most cases due to the ship design process being a largely evolutionary approach. Given current environmental preoccupations, the authors’ approach is strongly driven by concerns over sustainability, in contrast some other broadening approaches have, for example, done so with an emphasis on ship architecture [23, 24]. Thus the authors’ approach seeks to make the profession recognise that even at the preliminary stages of ship design that it is complex and challenging but more appropriate in having a wider boundary than a directly (or simplistically) economic one.

Life Cycle Assessment in mineral processing – a review of the role of flotation

Purpose The aim of this literature review is to investigate the role of the beneficiation stage in the Life Cycle Assessment (LCA) of metals and minerals with a focus on the flotation process. Methods The systematic literature search included LCA studies comprising the beneficiation stage in their system boundaries and resulted in 29 studies that met the criteria requirements and were analysed. First, the system boundaries are investigated, along with the level of detail in the description of the sub-processes (e.g. flotation) and data granularity. Then, the life cycle inventories are scrutinised: data transparency and the relation between system granularity and data availability is commented. Of particular relevance, the way in which the functional unit is dealt with is examined. Finally, studies impact assessments are compared and discussed, and key parameters are highlighted. Results and discussion For system boundaries, beneficiation is generally embedded into the mining stage. Even when described on its own, important sub-processes (e.g. flotation) are not considered, except for eight cases analysed. Functional unit definition is hindered by the output of the system being an intermediate product. Indeed, most studies use a declared functional unit but fail to provide its relevant characteristics, which is essential for a correct interpretation of results and for comparisons. Most studies rely on secondary data, not always presented transparently, to describe beneficiation. Results on the role of beneficiation in the metal value chain environmental impacts are conflicting, partly because of its site dependency. Site-dependent parameters found to be determining are ore grade, energy mix, mining technique, concentrate grade and ore mineralogy. Conclusions The flotation process, and more generally the beneficiation stage, is typically overlooked in LCA studies despite its growing relevance. Beneficiation not being assessed as a standalone stage, detailed in its subprocess, the use of outdated and secondary data, along with a lack of transparency in the inventory and in the key parameters are all factors that affect the environmental assessment of the entire metal and mineral sector, and thus the LCA of many products. Recommendation Greater efforts should be allocated to considering the sub-processes in the beneficiation stage, particularly flotation. Information on the identified key parameters should be available to the practitioners and sensitivity analyses to investigate their influence are recommended. Hotspots specific to flotation have been identified and should be used to orient data gathering when focusing on this process. Five options of functional unit and their application are recommended.

An Eco-Industrial Park-Based Method for Net Zero Community Creation

Much emphasis is placed on the role of Net Zero Communities (NZCs) in achieving a sustainable future. Systems research on the topic, including the application of bio-inspired techniques already used on other human networks, is currently hindered by the lack of case studies documenting the structure and quantity of energy, water, and waste flows within realistic NZCs. This work proposes and preliminarily tests a method of generating a database of hypothetical-realistic NZCs by expanding the system boundaries for well-documented Eco-industrial Park (EIP) networks. The expansion includes residential and commercial actors from the community surrounding the EIP. Past studies using Ecological Network Analysis (ENA) to improve the environmental and economic performance of these EIPs have resulted in a quantitative database of case studies. Combining these industrial hubs to nearby residential, commercial, agricultural, etc. actors can generate potential multi-use networks on which similar design work can be conducted. Three EIP to NZC cases are generated and analyzed focusing on their system structure. Cyclicity, an ENA metric used to quantify the presence and complexity of cyclic pathways in a network, has been shown to promote the efficient use of resources in both biological and human networks. Cyclicity values for the original EIP networks, the community additions, and the potential NZC case studies reveals that there are many meaningful interactions that occur between actors that are only visible once the system boundaries are expanded to the NZC level. This offers a glimpse into the potential benefits of approaching the NZ problem, and sustainable living more generally, on a system scale — an analysis that will be further enabled by the generation of an NZC database initiated by this work.

RE-DEFINING THE SYSTEM BOUNDARIES OF HUMAN-CENTRED DESIGN

Most services and products are designed in response to the needs, desires or expectations of humans. A variety of methodologies grouped by the term Human-Centred Design (HCD) have been deployed to formalise and improve this process, ranging from user-centred to participatory practices. However, the approaches’ consideration is primarily limited to individuals in their respective space and time.To examine these system boundaries in detail and address potentials for adaptation, this paper reviews dominant HCD methodologies, categorises them and highlights their respective characteristics. Further, concepts and methodologies from related fields are studied for potential contributions to HCD. This results in a proposed re-definition of the system boundaries of HCD by integrating spatio-temporal impacts on humans through an extended social, environmental and economic scope.The different studied approaches and varying impact assessments are exemplarily applied to the case study of urban mobility, in particular human-centred, scenario-based design approaches. However, the described methods and concepts are kept generic to ensure the applicability across various domains of design practice.

Plastic Waste Management: A Review of Existing Life Cycle Assessment Studies

Life Cycle Assessment (LCA) is a tool that can help to quantify the impacts of different processes to facilitate comparison and decision making. There are many potential methods for managing plastic waste, but it can be difficult to determine which methods are preferable in terms of environmental impact. Suitable existing LCA studies are identified through a screening process and the methodologies used and their outputs are compared. When undertaking an LCA, the researchers must define their scope and select their parameters, according to their aims and context, which leads to a wide variation in the approach taken. In this study, six parameters have been considered to analyze research progress in these fields regarding LCA, i.e., goals and scope, functional units, impact assessment categories, system boundaries, geographical context, and uncertainty analysis. These studies include the similar type of different studies considering plastic waste recycling, each taking a different approach to defining the system boundaries, revealing how the decision to include or exclude factors such as transport can have a significant impact on the outcomes. Additionally, compared to these similar studies on mixed-plastic waste management, different available options are used to quantitatively compare the impact outcomes, revealing how the context and parameter selection can affect the results. This review aims to highlight the prospect of LCA during the development of a waste management framework as an efficient waste recycling tool and recommend a research gap for the development of an improved management framework in the future.