This review thoroughly investigates the mechanical recycling of carbon fiber-reinforced polymer composites (CFRPCs), a critical area for sustainable material management. With CFRPC widely used in high-performance areas like aerospace, transportation, and energy, developing effective recycling methods is essential for tackling environmental and economic issues. Mechanical recycling stands out for its low energy consumption and minimal environmental impact. This paper reviews current mechanical recycling techniques, highlighting their benefits in terms of energy efficiency and material recovery, but also points out their challenges, such as the degradation of mechanical properties due to fiber damage and difficulties in achieving strong interfacial adhesion in recycled composites. A novel part of this review is the use of finite element analysis (FEA) to predict the behavior of recycled CFRPCs, showing the potential of recycled fibers to preserve structural integrity and performance. This review also emphasizes the need for more research to develop standardized mechanical recycling protocols for CFRPCs that enhance material properties, optimize recycling processes, and assess environmental impacts thoroughly. By combining experimental and numerical studies, this review identifies knowledge gaps and suggests future research directions. It aims to advance the development of sustainable, efficient, and economically viable CFRPC recycling methods. The insights from this review could significantly benefit the circular economy by reducing waste and enabling the reuse of valuable carbon fibers in new composite materials.

The demand for fiber-reinforced polymers (FRPs) has significantly increased in various industries due to their attributes, including low weight, high strength, corrosion resistance, and cost-efficiency. Nevertheless, FRPs, such as glass and Kevlar fiber composites, exhibit anisotropic properties and relatively low interlaminar strength, rendering them susceptible to undetected damage. The integration of real-time damage detection processes can effectively mitigate this issue. This paper introduces a novel method for fabricating embedded capacitive sensors within FRPs using a coating technique. The study encompasses two types of fibers, namely glass and Kevlar fiber/epoxy composites. The physical vapor deposition (PVD) technique is employed to coat bundle fibers with conductive material, thus creating embedded electrodes. The results demonstrate the uniform distribution of nanoparticles of gold (Au) along the fibers using PVD, resulting in a favorable resistance of approximately ≈100 Ω. Two sensor configurations are explored: axial and lateral embedding of the coated yarn (electrodes) to investigate the influence of load direction on the coating yarn. Axial-sensor configuration specimens undergo tensile testing, showcasing a linear response to axial loads with average sensitivities of 1 for glass and 1.5 for Kevlar fiber/epoxy composites. Additionally, onset damage is detected in both types of fiber composites, occurring before final fracture, with average stress at the turning point measuring 208 MPa for glass and 144 MPa for Kevlar. The lateral-sensor configuration for glass fiber-reinforced polymer (GFRP) exhibits good linearity towards strain until failure, with average gauge factors of 0.25 and −2.44 in the x and y axes, respectively.

This research introduces an innovative self-sensing hybrid composite material, skillfully integrating Kevlar and carbon fibers within a cohesive matrix. The study’s primary objective is to substantially improve the mechanical strength and decrease the weight of fiber-reinforced polymer (FRP) composites. By strategically employing carbon fibers as conductive channels and Kevlar fibers as an insulating barrier, this study innovatively embeds a capacitive sensing functionality within the composite matrix. This sensor is intricately designed for the real-time, continuous assessment of strain and the preemptive detection of structural integrity issues. The electromechanical attributes of the newly developed composite are meticulously evaluated using sophisticated scanning electron microscopy (SEM) and tensile testing methodologies. These evaluations disclose the material’s outstanding ability to detect preliminary damage. Results reveal a direct relationship between the composite’s axial stress responses and its sensitivity coefficient, quantified at an approximate value of 1.7. Additionally, the material demonstrates a consistent linear behavior under lateral strains until reaching its failure point, highlighted by remarkably high gauge factors of around -19. The integrated capacitive sensor exhibits exceptional sensitivity, providing invaluable insights into the material’s stress-strain dynamics and substantially enhancing its applicability in real-time structural health monitoring (SHM) settings.

Toxic metals in water systems pose a global health risk. Thus, multifunctional water monitoring and treatment materials are indispensable. Nickel ions, a frequent heavy metal pollutant, affect ecosystem function. However, developing affordable, functional materials for efficient heavy metal removal remains problematic. This study investigates the utilization of Al ₂O₃@g-C₃N₄ (AlCN) nanosorbent for adsorbing Ni (II) ions from aqueous solutions. The physicochemical analyses verify the creation of an AlCN nanosorbent with a mean size of 31.25 nm crystals and a specific surface area of 58 m ²/g. Batch adsorption experiments were conducted to examine the impact of pH, initial Ni (II) concentration, and adsorbent dose on the efficiency of Ni (II) removal using the synthesized (AlCN) nanosorbent. Adding Al₂O₃ to g-C₃N₄ nanosheets increased the adsorption capacity to a maximum of 410 mg/g under ideal conditions, as demonstrated by the results. Ni (II) ions adsorption kinetics on AlCN nanosorbents follow the pseudo-second-order kinetic model with an R ² value of 0.99, surpassing the Elovich pseudo-first model. The adsorption isotherm results show that the Langmuir model fits the experimental data better than the Freundlich and Temkin models, indicating a monolayer adsorption process for the AlCN nanosorbent. In addition, the AlCN exhibited multi-elemental adsorption ability and good recyclability. These findings can nominate the fabricated composite as a candidate for water treatment.

Like consumer electronic products, medical devices are becoming more complicated, with performance doubling every two years. With multiple commands and systems to negotiate, cognitive load can make it difficult for users to execute commands effectively. In the case of medical devices, which use advanced technology and require multidisciplinary inputs for design and development, cognitive workload is a significant factor. As these devices are very expensive and operators require specialized training, effective and economical methods are needed to evaluate the user experience. Heuristic evaluation is an effective method of identifying major usability problems and related issues. This study used heuristic evaluation to assess the usability of a CT scan and associated physical and mental loads for Saudi Arabian users. The findings indicate a gender difference in terms of consistency, flexibility, and document attributes, with a statistically significant gender difference in mental load.

Medical devices follow a trend, just like consumer electronic products, where they are becoming more complicated and performance is doubling every two years. Consequently, medical devices require a multidisciplinary team for design and development. Therefore, with so many commands and systems to deal with, users cognitive loads are challenged to effectively execute commands. In medical devices, the cognitive workload will play more of a role because it uses advanced technology, is extremely expensive and takes a great deal of specialization to operate. Thus, effective and economical methods are required to evaluate user experience. Heuristic evaluation is an effective method to identify major usability problems and highlight issues faced by users. Heuristic evaluation was adapted, to identify the usability of a CT scan on Saudi Arabian users and to identify if operating the CT scan can lead to physical and mental load effort. Contrary to the expected belief that young people are savvy in technology, this study found that this is not the case with CT, but rather working experience is more valuable in encountering usability catastrophic.