Xiaofei Cui

This study addresses the need to prioritise functional characteristics for safe and feasible maritime liquid hydrogen (LH₂) storage and transportation during early-stage system development. Quality Function Deployment (QFD) was applied through a House of Quality (HoQ) to map seven techno-socio-economic key performance indicator (KPI) categories against seven system-level functional characteristics for the LH2CRAFT concept. Survey respondents rated requirement importance, relationship strength, and implementation difficulty; normalised technical importance and difficulty scores were then combined using an equally weighted Multi-Attribute Utility Theory (MAUT) model. In this formulation, implementation difficulty was treated as a development criticality criterion indicating technical challenge, uncertainty, and validation needs rather than ease of implementation. The resulting scores represent stakeholder-informed development priorities and perceived areas of challenge; they do not provide empirical evidence of technical performance or validate one functional characteristic as superior to another. Cargo pressure and temperature control, material selection, and efficient design and implementation formed a shared high-priority development tier. This interpretation is supported by the close spacing of the prioritisation scores and the overlap observed in the underlying respondent assessments. Environmental mitigation measures received comparatively low prioritisation scores, suggesting that respondents viewed environmental performance mainly as an outcome of resolving core containment, safety, and implementation challenges. The framework provides a transparent basis for allocating design effort and planning validation activities, while the findings are interpreted alongside the relevant literature, regulatory requirements, classification guidance, and safety standards.

Ammonia as a fuel has been known for several years, but only relatively recently has it attracted interest for study and use as a marine fuel. A forthcoming generation of sustainable, economically viable, and safe technologies for the large-scale onboard storage of ammonia as a marine fuel is being developed. This article presents a structured approach to carrying out Quality Function Deployment (QFD) for evaluating a project solution at the strategic level. The “House of Quality” (HoQ) method is utilised since it provides the means for inter-functional planning and communications among people with different problems and responsibilities. The project requirements are defined and lead to functional technical characteristics to satisfy these needs. The approach allows for the application of a weighting scheme to rank the perceived relative importance of the requirements, the difficulty involved in implementing the technologies, and the relationship between requirements and functional technical characteristics. QFD analysis prioritises safety compliance, technical specifications, emission control, and operational efficiency. The added value of this work is beyond the life of a project since it may provide assistance to the stakeholders in assessing the applicability of ammonia fuel solutions given the resources available to them. This feature will enable the justification of further investment into specific technologies based on their potential impact.

The aviation sector is looking to replace conventional metals for aircraft doors with composite materials due to the latter’s potentially favorable combination of mechanical properties and low weight. However, little is known about the environmental impacts and economic costs associated with the production of such composite doors. This study conducts a Life Cycle Assessment and Life Cycle Costing on an example composite aircraft door to quantify its environmental and economic impacts. In addition, uncertainty analysis has been performed to enhance the quality of the assessment.