Cloud-Based Platform for the Circular Value-Chain

Recently, Fiber Reinforced Polymers(FRP) has been emerged as an alternative material to solve the corrosion of steel reinforcement in reinforced concrete structures. FRP exhibits higher specific strength and lower weight compared to steel reinforcement. Moreover, good resistance to corrosion of the FRP may be useful in aggressive environments causing deterioration such as chloride environment. However, causes for higher initial cost of FRP than that of steel, little information on the long-term behavior of FRP, and brittle failure make the efforts to apply FRP in civil structures slow. Glass fiber among the fibers used to manufacture FRP can be seen as the most beneficial material with regard to initial costs. But its low elastic modulus, which attains barely a quarter of steel, nay thus lead to excessive deflections when used as reinforcement for flexural members. This research was carried out on the tensile properties of hybrid rods made with glass and carbon fibers to improve those of FRP rod made with glass fiber. Parameters were resin type and the arrangement of glass and carbon fibers. The tensile properties of hybrid rods were compared with those of rods manufactured with only glass or carbon fibers. The results indicated that the tensile properties of hybrid rod were good when the carbon fiber was arranged in the core.

Internet of Things and Big Data – The Disruption of the Value Chain and the Rise of New Software Ecosystems

The relevance of the research is due to the growing demands of employers toward graduates and the difficulties related to students’ professional identity, which requires universities to create innovative systems of career support. The research objective is to form a scientifically grounded foundation for designing a modern IT solution in the field of career counseling. To achieve this goal, the following tasks were addressed: systematic analysis of fundamental career development theories was conducted; comparative analysis of existing digital platforms was performed to identify their methodological and functional gaps. The essence of research lies in the interdisciplinary synthesis of achievements in psychology, pedagogy, and information technology. The methodology includes a systematic literature review and comparative analysis, on the basis of which, using the method of theoretical synthesis, conceptual requirements for the future system were formulated. The main results showed a significant gap between the deep understanding of career development in scientific theories (in particular, in SCCT) and the utilitarian, fragmented nature of existing IT tools. The main conclusion and key result of the work was the formulation of four fundamental psychological and pedagogical requirements for an effective IT platform: reliance on scientifically based diagnostics, dynamic personalization of the development trajectory, integration of highly effective practices (mentorship, project experience), and creation of a unified supportive ecosystem. The value and scientific significance of the work lies in the operationalization of complex psychological constructs into specific principles for IT system design, which creates a “bridge” between the humanities and EdTech. The practical significance consists in providing a clear analytical foundation that can be used by developers and universities to create an innovative tool capable of enhancing graduates’ awareness, self-efficacy, and competitiveness.

This study investigates the impact of fiber reinforcement, specifically carbon and glass fibers, on the flexural behavior and fracture performance of cementitious composites with varying strengths The strength grades of the composites were designated as high-strength, medium-strength, and low-strength. The composites were reinforced with woven glass and carbon fibers at different length/span ratios and subjected to flexural testing to evaluate key parameters such as strength, strain, and modulus. High, medium, and low-strength prism specimens were prepared using specific cement dosages (634.26 kg/m 3 for high strength, 535.26 kg/m 3 for medium strength, and 432.65 kg/m 3 for low strength) with corresponding water-to-cement ratios of 0.3, 0.4, and 0.65, respectively. The results indicate that fiber reinforcement significantly enhances the flexural properties of all composite categories, with the most notable improvements observed in the medium-strength and high-strength composites. Among the composites, the carbon fiber-reinforced high-strength composite (HS-CFRC-4/7) demonstrated the highest flexural strength (10.00 MPa), a 73% improvement over the control specimen. However, a diminishing return in strength gain was observed in high-strength composites, suggesting weaker anchorage bond between woven fiber and the specimen where the matrix strength becomes the dominant factor. Additionally, carbon fibers exhibited a higher strain capacity than glass fibers, with consistent increases in ductility across all composite groups. Fracture analysis revealed distinct failure modes, including flexural cracks, diagonal shear cracks, and delamination, especially in high-strength composites.

In the aircraft manufacturing industry, the strength and weight of the material is one of the important considerations in structural design. Composite material is a material composed of two or more forming materials, each of which has different mechanical properties. Aircraft structure in this era are 50 - 80% composed of glass or carbon fiber composite materials as reinforcement. Unfortunately, these fibers when recycled produce harmful CO gas, difficult to degrade naturally and cause itching when in contact with human skin. For this reason, environmentally friendly and strong fibers are needed to replace the role of glass or carbon fibers. Is a bamboo plant, which is abundant in Indonesia which is considered suitable as a substitute material. In this study, a mechanical test and descriptive analysis were carried out on the strength of the composite material with variations in the types of bamboo fibers apus, wulung, tutul and petung. These fibers are arranged with epoxy resin and hardener as a binding material (matrix). And each fiber will be arranged in 0 ° pattern to the matrix. Then each material with a different fiber type will be tested for tensile and bending to obtain the value of stress and strain that occurs at its maximum loading. And the result is the average tensile stress value (Mpa) composite material of apus bamboo is 75.95, wulung bamboo 49.92, petung bamboo 112.73, tutul bamboo 83.85. Then the average bending stress (Mpa) composite material of apus bamboo was 239.073, wulung bamboo 214.236, petung bamboo 249.67, tutul bamboo 272.79. With this result, bamboo fiber composites are considered to be able to replace the role of carbon or glass fibers, as an alternative composite material in some parts of the interior fuselage of aircraft panels. Keyword: Composites material, Matrix, Bamboo Fibers, Carbon and Glass Fibers, Stress and Strain.

The development and testing of a pseudoductile hybrid fiber-reinforced polymer rod consisting of glass and carbon fibers is described. Two different hybrid forms were considered for the development of the hybrid rods, including (1) random dispersion of the glass and carbon fibers; and (2) a core-shell design with a glass fiber core protected by the carbon fiber shells. The mechanical properties of the hybrids were evaluated through uniaxial tension tests. The hybrid rods developed by way of the core-shell approach exhibited pseudoductile properties that included a yield point of 1,153 MPa and an ultimate strength of 1,191 MPa, with a strain of 3.5% at ultimate. The experimental program also included damage assessment by way of a single-channel fiber optic acoustic emission (AE) sensor. The acoustic emission technique was employed for real-time determination of the progressive damage due to rupture of fibers. Moreover, the spectral energies of the frequency spectrum from the AE signals were employed for assessment of the state of damage in the rods. The spectral energies distinguish between the carbon and glass fiber ruptures. This differentiation of signals provides information about the condition and the state of health of the hybrid rod.

The paper offers a historical outline of the main positions and protagonists of feminist epistemology as a specific field in philosophy at the end of the twentieth century, in the context of a feminist critique of knowledge in academia in general as part of international feminist movements. The main question discussed is whether there is a specific feminist concept of philosophical and scientific knowledge. If so, what is its innovative aspect? What are the philosophical problems in arguing for feminist knowledge? Is there a specific insight or methodological approach? A further question is what role, if any, feminist epistemology plays in the interdisciplinary field of Gender Studies. The discussion will centre on how feminist epistemology relates to non-scientific practices. In particular, the role of the concept of objectivity in feminist epistemology will be elaborated. This will illuminate the connection between the feminist knowledge project with other emancipatory projects and outline how feminist constructivism might play a prominent role in this context in the twenty-first century.

Reforçar estruturas é uma prática que demanda conhecimento do sistema de reforço e do comportamento da estrutura interferida. A necessidade de recuperação e reforço em estruturas de madeira, em detrimento à troca das peças de um arranjo estrutural, exigiu da construção civil a procura por métodos eficientes e confiáveis. Dentre esses métodos tem se destacado o uso de fibras, sendo as de carbono, vidro e aramida as mais pesquisadas e utilizadas. Nesta pesquisa avaliou-se a associação da fibra de vidro e de carbono à madeira de Eucalyptus grandis in natura e autoclavada com o uso do adesivo epóxi, objetivando analisar a viabilidade técnica desse tipo de combinação no reforço de estruturas de madeira por meio da interpretação dos resultados de ensaios de tração e modos de ruptura. Definidas as variáveis, procederam-se os ensaios de tração direta nas amostras. Os resultados apontaram uma superioridade da fibra de carbono em relação às fibras de vidro quanto à tensão de ruptura. Com a aplicação da fibra de carbono em corpos de prova fraturados, obteve-se uma recuperação de 90% da resistência em comparação aos corpos de prova sem fraturas. Em relação ao substrato, de um modo geral, as madeiras de Eucalyptus in natura e autoclavada não apresentaram diferenças significas no desempenho quanto à aderência da resina epóxi.

Resin mineral composite attracted much attention in the field of elementary machine components because of the excellent performance in alleviating vibration. However, applications of resin mineral composite are restricted due to its limited mechanical properties. In this paper, the effects of the aggregate gradation, the maximum diameter of the aggregate, and the mass fraction of the resin on the mechanical strength were investigated. In addition, influences of fiber types (glass fiber and carbon fiber), fiber length, mass content of fiber, and surface treating techniques (ultrasonic cleaning, oxidation by HNO3, coupling treatment by silane) on the mechanical strength of resin mineral composite were also investigated. Experimental results show that the compressive strength of resin mineral composite first increases and then decreases as the maximum aggregate diameter, the fractal dimension of the aggregate gradation, and the resin dosage increase. The best compressive strength was obtained when the maximum diameter of aggregate is 15 mm, the fractal dimension of the aggregate gradation is 2.45, and the mass fraction of the resin is 9%. Results also show that the best mechanical strength was obtained when the lengths of the fibers are 10 mm and the mass fraction of the glass (carbon) fiber is 0.1% (0.05%). Compared with resin mineral composite with no fibers, the compressive strengths of resin mineral composite reinforced by glass fibers and carbon fibers treated with three-step treating technique increased by 16.62 and 14.63%, respectively. And the flexural strength of resin mineral composite reinforced with carbon fibers treated with three-step treating technique increased by 18.3%. The flexural strength of resin mineral composite reinforced with glass fiber treated with two- and three-step treating technique increased by 9.67 and 5.7%, respectively. In addition, the mechanism of the influences of the fiber whose surfaces were treated on the mechanical strength of resin mineral composite was revealed by scanning electron microscopy.

This study investigates the Charpy impact strength of unidirectional (UD) carbon fiber, unidirectional (UD) glass fiber, and hybrid composite materials. The results revealed distinct differences in their energy absorption capacities and fracture behaviors. Carbon fiber composites exhibited brittle fractures and low energy absorption, while glass fiber composites displayed significant deformation without a complete fracture, absorbing more energy. The hybrid laminate showed enhanced impact strength, absorbing nearly one-third more energy than the carbon fiber counterpart, and offering a balanced performance improvement through fiber hybridization. Statistical analysis confirmed that the improvement in impact performance among the tested groups was significant. Microscopic analysis of the damaged specimens revealed different damage modes: glass fibers exhibited deformation and mode I delamination, while carbon fibers showed brittle fractures and extensive delamination. Hybrid specimens displayed a combination of damage modes, enhancing their overall impact resistance. These findings demonstrate the potential of hybrid composites for applications requiring balanced mechanical properties, particularly impact resistance. The hybridization method allows for the integration of carbon fibers' high strength with glass fibers' superior impact resistance, enhancing material performance under sudden impact conditions. Future research should focus on optimizing the hybridization process and exploring additional fiber combinations for enhanced material properties.

The aim of the article is to analyze the influence of short coir, glass and carbon fiber admixture on the mechanical properties of fly ash-based geopolymer, such as: flexural and compressive strength. Glass fiber and carbon fibers have been chosen due to their high mechanical properties. Natural fibers have been chosen because of their mechanical properties as well as for the sake of comparison between their properties and the properties of the artificial ones. Fourth series of fly ash-based geopolymers for each fiber was cast: 1, 2, and 5% by weight of fly ash and one control series without any fibers. Each series of samples were tested on flexural and compressive strength after 7, 14, and 28 days. Additionally, microstructural analysis was carried out after 28 days. The results have shown an increase in compressive strength for composites with fibers—an improvement in properties between 25.0% and 56.5% depending on the type and amount of fiber added. For bending strength, a clear increase in the strength value is visible for composites with 1 and 2% carbon fibers (62.4% and 115.6%). A slight increase in flexural strength also occurred for 1% addition of glass fiber (4.5%) and 2% addition of coconut fibers (5.4%). For the 2% addition of glass fibers, the flexural strength value did not change compared to the value obtained for the matrix material. For the remaining fiber additions, i.e., 5% glass fiber as well as 1 and 5% coconut fibers, the flexural strength values deteriorated. The results of the research are discussed in a comparative context and the properties of the obtained composites are juxtaposed with the properties of the standard materials used in the construction industry.

UV, FIRT and surface properties of fiber reinforced low-density polyethylene laminated composites

The growing use of carbon and glass fibres has increased awareness about their waste disposal methods. Tonnes of composite waste containing valuable carbon fibres and glass fibres have been cumulating every year from various applications. These composite wastes must be cost-effectively recycled without causing negative environmental impact. This review article presents an overview of the existing methods to recycle the cumulating composite wastes containing carbon fibre and glass fibre, with emphasis on fibre recovery and understanding their retained properties. Carbon and glass fibres are assessed via focused topics, each related to a specific treatment method: mechanical recycling; thermal recycling, including fluidised bed and pyrolysis; chemical recycling and solvolysis using critical conditions. Additionally, a brief analysis of their environmental and economic aspects are discussed, prioritising the methods based on sustainable values. Finally, research gaps are identified to highlight the factors of circular economy and its significant role in closing the life-cycle loop of these valuable fibres into re-manufactured composites.

An all-hydrocarbon resin was synthesized using commercially available materials. The resin undergoes spontaneous cure at around 200°C and cationic cure at around 100°C. This resin gives composites with excellent properties when used with glass and carbon fibres. Flexural modulus values (DuPont DMA) of ca 66 GPa were obtained for carbon fibre composites compared to 42 GPa for epoxy/carbon composites made in our laboratories using commercially available materials. The modulus value at 300°C dropped to 10% of the room temperature value for epoxy composites, whereas the new material maintained 60% of its room temperature value. When brought back to ambient temperature, the modulus value had increased to 81 GPa for the new resin samples while that of the epoxy composite dropped to 23 GPa, Glass fibre composites with the new resin performed similar to the analogous epoxy material up to 200°C but maintained their properties up to 300°C while those of the epoxy composite were drastically reduced. Boiling water treatment had a large affect on the epoxy-glass samples but no observable affect on the glass composites made with the new resin. Scanning electron micrographs showed bonding of the new resin to both carbon and glass fibre surfaces. TGA analysis of both resin and composites showed decomposition beginning at 375°C. This new thermosetting resin thus offers a low-cost approach to glass and carbon composites possessing excellent thermal and physical properties, and out standing hydrolytic stability.

Polymer composites consisting of a thermoplastic polymer forming the matrix phase and a large amount of inorganic particles (commonly referred to as fillers) or glass fibers, which are often referred to as particulate-filled polymers, are very common in the plastics and elastomer’s industries (Deanin and Schott 1974; Kraus 1965; Lubin 1969). Polymer composites are developed to achieve a set of properties not possessed by the thermoplastic polymer (i.e., polymeric matrix) alone. Polymeric matrices can be thermoplastics, which soften and behave as viscous liquids when heated to above their glass transition temperatures (in the case of amorphous thermoplastic polymers) or above their melting temperatures (in the case of semicrystalline thermoplastic polymers). Polymeric matrices can also be thermosets, which undergo a transformation from a viscous resinous liquid to a hard or rubbery solid in the presence of heat and/or curing agents. There are numerous industrial products made of particulate-filled polymeric materials; for example, thermoplastic polymers filled with mica or calcium carbonate, carbon-black-filled elastomers, thermoplastic polymers or thermosets reinforced with glass fibers or carbon fibers. The ultimate goal of adding fillers to a thermoplastic polymer and adding glass fiber or carbon fiber to a thermoset is to improve the mechanical properties of the polymer. However, fillers, glass fibers, or carbon fibers themselves usually supply little or no reinforcement since there is little interfacial interaction between a thermoplastic polymer and fillers, and between a thermoset and glass fiber or carbon fiber. This has led to the development of “coupling agents,” chemical additives capable of improving the interfacial bonds between a thermoplastic polymer and fillers, and between a thermoset and glass fibers or carbon fibers (Plueddemann 1982). The use of coupling agents for the surface modification of fillers to reinforce thermoplastics has generally been directed towards improving the mechanical strength and chemical resistance of composites by improving adhesion across the interface. When inorganic fillers or glass fibers are added to a thermoplastic polymer, the resulting material exhibits a complex rheological behavior, quite different from the rheology of neat homopolymers presented in Chapter 6.