Journal of Composites Science

Carbon dioxide (CO₂) and methane (CH₄) are major greenhouse gases, and their increasing emissions contribute significantly to global warming. Dry reforming of methane (DRM) offers a promising route to mitigate these emissions by simultaneously utilizing both CO₂ and CH₄ and converting them into syngas, a valuable intermediate for producing fuels and chemicals. Nickel-based catalysts are widely used in DRM due to their high activity and cost-effectiveness. However, their performance depends strongly on metal loading and support properties. This study aims to investigate the effect of different NiO loadings (40, 50, and 60 wt%) on the structural and morphological characteristics of NiO-YSZ and NiO-SDC catalysts synthesized via the impregnation method. In this method, yttria-stabilized zirconia (YSZ) and samarium-doped ceria (SDC) powders were dispersed into a nickel precursor solution to form supported catalysts, which were then characterized to evaluate their structural integrity, crystallinity, and surface morphology. The results showed that higher NiO loadings generally improved the structural and morphological features, with NiO-SDC demonstrating better characteristics than NiO-YSZ. These findings provide essential insights that will guide future work on fabricating membranes using these catalysts for the CO₂-CH₄ dry reforming process.

Vacuum infusion experiments were conducted to characterize the elastic recovery and thickness effect in the vacuum infusion molding process (VIMP). The results indicate that both the local fluid pressure and the part thickness increment increase with flow propagation until filling completion, and subsequently decrease during the post-filling stage. The maximum thickness increment increases with the number of reinforcement layers, while the thickness-increment rate decreases due to the enhanced compliance of the reinforcement. Specifically, for reinforcements with 10, 20, and 30 layers under in-plane 1D (One-Dimensional) flow, the thickness-increment rates are 4.97%, 4.74%, and 3.86%, respectively. In out-plane 1D flow, a distinct progressive three-stage thickness growth is observed, with corresponding increment rates of 43.7%, 23.0%, and 15.8% for 10, 20, and 30 layers, highlighting a significantly more pronounced effect. In contrast, for both coupled seepage-flow configurations (A and B), the thickness-increment rate shows no significant variation with layer number and remains consistently around 6%. This suggests that the thickness effect is offset by the coupled seepage-flow interaction of in-plane, out-plane, and distribution medium (DM) flows. It can be concluded that elastic recovery decreases with increasing part thickness. The thickness effect exerts a positive influence on the vacuum infusion molding of large-scale (thick-section) composite structures. Both elastic recovery and thickness effect are closely related to the injection mode (process strategy), with the effect in out-plane 1D flow being significantly greater than that in in-plane flow and coupled seepage flow.

In this paper, the bond performance of tensile lap-spliced Glass and Basalt Fiber-Reinforced Polymer bars is investigated in high-strength concrete. Eighteen large-scale GFRP-reinforced concrete beams were fabricated and subjected to four-point loading. Key parameters explored included bar diameter and splice length for both GFRP and BFRP reinforcement. The results indicate that the flexural capacity of GFRP-reinforced beams was comparable to that of BFRP-reinforced beams, though BFRP bars exhibited marginally superior bond and strength with concrete. The bond strength of spliced FRP bars was directly proportional to the splice length. This study also determined that characteristics of development lengths necessitate splice lengths that exceed the bar diameter 40 times to mitigate bond stress. Critical splice lengths, derived from experimental findings, were compared with existing models and code-based equations, specifically, Guide for the Design and Construction of Structural Concrete Reinforced with Fiber-Reinforced Polymer Bars (ACI 440.1R-15) and Canadian standard that provides comprehensive guidelines for incorporating Fiber-Reinforced Polymer reinforcement in concrete structures (CSA S806-12). Both codes were conservative in splice length prediction for GFRP and BFRP bars, with ACI 440.1R-15 showing greater accuracy for BFRP bars with a larger diameter. A modification factor, based on hyperbolic functions, is proposed to enhance the accuracy of ACI 440.1R-15 in predicting splice lengths for various FRP bar diameters.