Hydrogen has emerged as a cornerstone of global decarbonisation strategies, offering a flexible pathway to reduce dependence on fossil fuels and accelerate progress towards net-zero targets. However, the development of a globally integrated hydrogen economy remains uneven, reflecting disparities in renewable energy potential, infrastructure readiness, investment capacity, and policy commitment. To better understand these differences and the barriers they create, this study undertakes a comprehensive comparative assessment of the global hydrogen supply chain encompassing resources, production, storage, transport, and end-use applications. Further, a structured analytical framework comprising ten principles and twenty-nine sub-factors was developed to evaluate national hydrogen policies, technological readiness, and enabling conditions across twenty-six countries. The results show that the United States, China, Japan, South Korea, and Germany lead global progress, while many countries remain at an early stage of engagement. These findings further inform persistent regional asymmetries and emphasise the need for stronger international coordination. Drawing on these findings, the paper advances targeted policy and research recommendations to lower production costs, expand storage and transport capacity, and harmonise regulatory frameworks, thereby defining a coherent pathway towards a secure, cost-competitive, and equitable global hydrogen economy by 2050.

Plastic Recovery Facilities are typically designed to process a specific, predetermined mix of plastic in the infeed. However, in many cases, the composition of the infeed varies seasonally and regionally. These variations may result in bottlenecks within sorting machines, thereby causing inconsistencies in the quality and quantity of recovered material. While most recovery facilities attempt to mix different bales before feeding them into the sorting line, relying on trial and error based on the material compositions of those bales, there is a lack of a systematic approach to this process. This paper introduces a systematic approach to plastic sorting within a plastic recovery facility, where the entire recovery process flow is dynamically modelled and validated. By identifying bottleneck regions within the system, infeed bales can be premixed to achieve the designed proportions, ensuring that machines and process lines are optimised for maximum efficiency. A pre-waste survey is necessary to achieve premixing, and the cost is justified by the benefits of the final return. To enhance the efficiency, it is crucial to implement a dynamic mixing model adaptable to daily variations in infeed. In this study, the dynamic optimisation model is designed in the form of simple mixing charts, allowing for on-site premix adjustments to bales without the need for additional equipment or tools. The proposed design chart based mixing methodology can be adopted across the globe to increase the output of established plastic recovery facilities.

The adoption of sustainable construction materials in the building sector is increasing, driven by global net-zero targets, regulatory pressures, and growing demand for low-carbon and resource-efficient construction. In this context, this research investigates the feasibility of using bio-based fibre-reinforced epoxy resin composite laminates with recycled polyethylene terephthalate cores in structural insulated panels (SIPs) as an alternative to conventional SIP systems. Laminates were fabricated via a wet layup method using two epoxy resins and five fabric types, including flax, hemp, and recycled PET fabrics. Tensile and flexural testing revealed that hemp fabric paired with a fully bio-based epoxy provided the optimum combination of strength and elastic modulus. Small-scale SIP prototypes utilizing optimum laminate and rPET cores were tested for edgewise compression and flexure against expanded polystyrene (EPS) equivalents. The rPET SIPs demonstrated compressive and flexural capacities two to three times greater than the EPS panels. These findings demonstrate the potential of sustainable fabric-reinforced epoxy resin composite SIPs for specialized high-performance construction applications where enhanced structural capacity and sustainability are required. Although further work is needed to address cost, fire performance, and scalable manufacturing, the proposed system presents a promising alternative for next-generation sustainable building systems.

Ultra-High Strength Concrete (UHSC) (>100 MPa) is a mechanically superior material compared with the Normal Strength Concrete (NSC) due to its inherent performance characteristics. Improved modulus of elasticity is one of the key target characteristics in the development of UHSC. Macroscopic response of UHSC is a result of a multitude of phases in different spatial length scales such as mesoscale, microscale, nanoscale etc. and investigating these spatial scales can yield a better understanding about contribution of each heterogenous phases to the macroscopic behaviour of UHSC. In this paper, a new multiscale modelling method including procedures to obtain micro/nano scale properties is proposed to predict the macroscopic elastic modulus using nanoindentation experiments, hydration simulations, Scanning Electron Microscopy (SEM) and Finite Element Representative Volume Element (FE-RVE) modelling.Characterization of nanomechanical properties of the cementitious composite was carried out using nanoindentation, microstructural characterization was performed using scanning electron microscopy, and hydration simulation of the cementitious paste was carried out using Virtual Cement and Concrete Testing Laboratory (VCCTL) software. A five-level multiscale framework is proposed for UHSC and results from these experimental testing and simulations were used as inputs in the proposed framework.A novel algorithm which can model any volume fraction of different phases was developed to generate geometries for RVEs to be used in FE-RVE simulations. Upscaling of elastic modulus using FE-RVE was found to be very accurate, and this method can generate detailed variation of microfields inside the RVE. A parametric study was carried out on how varying inhomogeneities in the RVE, boundary conditions, and the shape of the inhomogeneities would affect the homogenized elastic modulus.Continuum micromechanics models such as Mori-Tanaka method and Self Consistent Scheme were used for the analytical homogenization at each scale for comparison with FE RVE method. The results of the proposed FE-RVE analysis, the Mean Field Homogenization (MFH) method, and experiment were compared and found to be a very good fit.