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The application of pultruded glass fibre-reinforced polymer composites (PGFRPC) as a replacement material for conventional wooden cross-arm in high transmission towers is relatively new. Although there are several studies on enhancement of the cross-arm structure, there is still a lack of study on the elastic properties of a full-scale PGFRPC cross-arm enhanced with honeycomb sandwich structure. To full-fill the gap, this paper describes an experimental methodology used to obtain the elastic properties of the cross-arm using a three-point bending (3-PB) flexural test by following ASTM D790 standard for deflection behaviour and flexural creep response. The investigation involved several cross-arm members subjected to loading across different span lengths by propose two methods in order to measure the effective cross-arm member section flexural modulus (Ec) and shear modulus (Gc). The creep behaviour of the panels was successfully modeled using Findley's power law, confirming the ability of this empirical approach to simulate the viscoelastic response of the cross-arm. Next predictions were made for up to 50 years of service and the results shows the elastic modulus reduction for the enhanced cross-arm with the honeycomb sandwich structure was approximately reduce to 70 % compare with existing cross-arm which reduce almost 75 % at 50 years of application. The enhanced cross-arm exhibited lower deflection and better creep resistance and increased the bending strength of the cross-arm as well as extended its potential lifespan. Predictions indicated that the enhanced cross-arm maintained better mechanical properties over time compared to the existing one.

The utilization of pultruded glass fibre-reinforced polymer composites (PGFRPC) to replace traditional wooden cross-arms in high transmission towers is a relatively recent development. While there have been numerous investigations into enhancing cross-arm structures, there remains a notable absence of research focused on the elastic characteristics of a full-scale PGFRPC cross-arm, particularly one enhanced with a honeycomb sandwich structure. To full-fill the gap, this paper presents an experimental and numerical study through cantilever beam flexural tests on assembled cross-arm condition to examine deflection behavior and the flexural creep response. For deflection behavior, the load was applied up to actual working load. For creep behavior, the hanging load was applied for 1000 h in open area condition followed ASTM D2990 standards. By using Findley's power law, confirming the ability of this empirical approach to simulate the viscoelastic response of the cross-arm. The results obtained prove that the addition of a honeycomb sandwich structure reduced deflection and improved resilience against bending forces, enhancing specific points' elastic modulus slightly. Long-term creep tests revealed Point Y3 had the highest strain, but the enhanced cross-arm displayed superior resistance and a shorter viscoelastic transition period, indicating increased stability. Besides that, the Findley's Power Law Model effectively represented creep behavior for both cross-arm types, with low errors. Over 50 years, both versions showed a significant reduction in average elastic modulus, with the enhanced variant 20 % stronger due to the honeycomb structure. In conclusion, this study validates the superior creep properties of the enhanced PGFRPC cross-arm and demonstrates the honeycomb sandwich structure's substantial role in increasing strength and extending the cross-arm's lifespan, making it a valuable enhancement for such applications.

The effects of expansive agents (EAs) and glass fibres (GFs) on the splitting strength and fracture performance of seawater and sea-sand concrete (SSC) were investigated. It was found that adding sole EAs or GFs improved the splitting strength, flexural strength, fracture energy, and initial and unstable fracture toughness of SSC. The combination usage of EAs and GFs maximumly increased the aforementioned indexes by 65%, 75%, 155%, 101%, and 82%, respectively. The optimal EA content was 3%–6% and increased with the increase of GF contents. The constitutive model of SSC reinforced with EAs and GFs under tension proposed in this study agreed well with the experimental results.

The use of scrap tyres in construction materials has been promoted to curb the environmental exploitation caused by the open disposal of non-biodegradable waste rubber. Tyre grinds as aggregates in geopolymer concrete (GPC) would increase its sustainability value by reducing the consumption of natural aggregates. Although there is limited literature addressing the damage to GPC characteristics caused by rubber aggregates, this investigation was designed to determine the extent of possible side effects of using crumb rubber (CR) in GPC. Additionally, this investigation aims to address any resulting reduction in strength and durability using additives such as cement and fibres. Geopolymer specimens with CR replacement of fine aggregates by volume (0, 5, 10 and 15%) showed a compressive strength reduction of up to 17% when tested according to ASTM standards. Substituting the total binder by weight with Ordinary Portland cement (OPC) (0%, 5%, 10%, 15%, and 20%) improved the microstructural integrity of the rubberised geopolymer mix with the highest percentage of OPC. Despite producing new and additional binding products (CSH and CASH gels), the GPC surface readily disintegrated under acid exposure. Optimum glass fibres (GF) reinforcement (0.30%) effectively disrupted the GPC pore network, consequently reducing the acid permeability of the matrix. Further addition of steel fibres (SF) enhanced the GPC specimen's compressive and flexural strength. To analyse the cumulative effect of these additives on GPC microstructure, supporting tests such as scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared (FTIR) spectroscopy were carried out. Although these additives enhanced the overall performance of rubberised geopolymer, it might somewhat reduce its green aspect.

In this study, Date Seed Granulated Powder (DSGP) was used as a reinforcement material for Glass Fibre Reinforced Epoxy resin (GFRE) composite. Specifically, the DSGP was prepared and added to Glass fibre reinforced Epoxy composite using the hand lay-up method. The DSGP reinforced GFRE was produced in different weight ratios of 0 %, 10 %, 20 %, 30 %, 40 % and 50 % wt. The mechanical properties of the developed specimens of the DSGP reinforced GFRE composite were investigated using the universal INSTRON tensile machine, flexural testing equipment, Izod impact testing machine (ASTM D256 standard) and Rockwell Hardness testing machine for hardness test. Results of the tests showed maximum values of tensile strength, flexural strength and Hardness Number as 271 MPa, 241 MPa and 97 HRB for the 50, 40, 30, 20 and 10 % wt. GDS samples respectively. Energy absorption capacity (U in Joules) of the samples were also determined. From the results obtained, the best variation of the reinforcement of Glass Fibre Reinforced Epoxy with Date seed granules is the GFR-40 % wt. GDS composition. This study therefore proves that Glass fibre –Date seed reinforced composites are good alternatives to Glass fibre composites, since they gave higher mechanical properties at lower cost.

Expansive soils have typical expansion and contraction properties. Under the action of dry-wet cycles, the mechanical properties and cracking behaviour of expansive soil change significantly due to repeated expansion and contraction, which results in engineering problems in expansive soil areas. The resource utilization of solid waste in civil engineering is in line with environmental protection policies and is an important solution to engineering problems. In this study, two types of fibres that can be recycled from solid waste are selected: glass fibre (GF) and polypropylene fibre (PF). Through indoor shear strength and dry-wet cracking tests, the influence of fibre content on the shear strength parameters of expansive soil is quantitatively analysed, the enhancement effect of fibres on the crack resistance of expansive soil is evaluated, and the crack characteristics of fibre-reinforced expansive soil as a function of different drying times, numbers of dry-wet cycles and soil layer thicknesses are explored. The results show that both fibre types significantly enhance the shear properties of expansive soils, and types of fibre-reinforced soil exhibit a peak in shear strength parameters at a certain fibre content. Fibre reinforcement inhabits expansive soil cracking to some extent, and both fibre types exhibit the best crack inhibition effect at a fibre content of 0.5%. The fundamental factor controlling the performance of fibre-improved expansive soil is the adhesion of the expansive soil particles to the fibres, and the PF surfaces are much rougher than the GF surfaces, which can further facilitate the interactions between the fibres and soil grains. In general, the improvement effect of PF is better than that of GF.

This paper presents the results of an experimental investigation of the behaviour and strength of hybrid kenaf/glass fibre-reinforced epoxy tubes subjected to axial intermediate-velocity impact loading. The specimens under axial intermediate-velocity impact involve three filament winding orientation parameters of ±30°, ±45° and ±70° of hybrid kenaf/glass fibre-reinforced epoxy and glass fibre reinforced-epoxy. All materials and sampling were prepared at SIRIM STV Malaysia laboratory by using automated filament winding machine to obtain a proper intraply hybrid kenaf/glass composite tube fabricating procedure. Results from the study showed that the concept in fabricating intraply hybrid filament winding technique of natural/synthetic materials has performed similar physical crashworthiness of synthetic composite tube with various progressive crushing behaviours. It was also observed that the winding orientation parameter at θ = 30°, 45° and 70° of the hybrid composite tube have increased the energy absorber properties with 33%, 34% and 56% respectively, compared to the GFRP.

Structural health monitoring of composite structures enables early damage detection to prevent critical component failure. Surface-mounted strain gauges are commonly applied to monitor the integrity of composite structures in highly loaded areas. However, strain gauges can only measure strain on the structure’s surface and are exposed to environmental influences. Within this paper, fully integrated carbon nanotube thin-film sensors for strain and damage sensing in glass fibre reinforced polymers (GFRP) via electrical resistance measurements are presented. Single wall carbon nanotube epoxy thin-films were manufactured using a manual film applicator, partially pre-cured, placed on dry glass fabrics and infused in a resin transfer moulding process. The mechanical properties of the composites and strain sensing capabilities of the integrated sensors were studied for various load cases and different laminate lay-ups. Results of quasi-static and step-wise three-point bending and tensile tests show that the integrated films allow for localised strain measurements in GFRP without significant loss of mechanical properties. Open hole tensile tests proof the ability to monitor local strain and damage in highly loaded areas enabling failure prediction via threshold resistance change values. The proposed thin-films enable a tailored strain and damage monitoring of GFRP offering the possibility for measurements at different material depths, over large sections or selectively in highly loaded areas. The manufacturing process is easily automatable and suitable for large scale manufacturing.

Ankle-foot orthotics need ideal specification of being light-weight, high strength, tough, stiff, and durable. Reinforced polypropylene (PP) composites with enhanced mechanical properties are the most favorable materials being used in this field, but still, it is challenging to achieve balanced blend of strength and toughness in the composites. The present study thus aims to achieve the challenging task of simultaneous improvement in stiffness and toughness in reinforced PP composites exploring the synergistic reinforcement effect of glass fibers (GFs) and nano silica (SiO2) as multiscale fillers and ethylene propylene diene monomer (EPDM) as impact modifier. EPDM is used as toughness modifier, addressing the brittle behavior, but at the cost of the strength of the polymer. Combined use of micro and nanofillers as reinforcement in toughened polypropylene provides a potential approach to balance the strength while maintaining the toughness. GFs could offer high strength and nanofillers offer ductile fracture to the material. PP, PP/GF, PP/EPDM/GF composites and PP/EPDM/GF/SiO2 nanocomposites are fabricated through melt blending technique and are characterized through SEM, mechanical evaluation, nanoindentation and dynamic mechanical analysis. Mechanical properties are evaluated in accordance with ASTM standards. PP/EPDM/GF/SiO2 nanocomposites exhibits remarkable enhancement in Tensile strength, tensile modulus, impact strength and percent elongation at break by 49 MPa (55% increase over PP), 2450 MPa (145% increase), 145 J/m (13% increase) and 156% (160% increase) respectively. The exceptional improvement in reduced modulus and hardness reveals good interfacial properties. Loss factor decrement reveals elastic behavior of nanocomposites suitable for thermoforming of nanocomposites for orthotic device fabrication., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Aging was carried out by introducing the materials into a climatic chamber under appropriate conditions of temperature, humidity and time. The materials are made of two types of weaving (2/2 Twill, 8H Satin) glass fibre, and (8H Satin) carbon fibre. The matrix was polyetherimide(PEI). In order to characterize the interlaminar fracture a mechanical test was carried out using the mode I Double Cantilever Beam (DCB) and mode II End Notched Fixed (ENF) tests. The analysis consists of knowing the different failure mechanisms which have generated the hygrothermal aging.En este trabajo se realiza un estudio sobre la influencia del envejecimiento higrotérmico en el comportamiento a fractura interlaminar de tres tipos de compuestos, dos de ellos reforzados con tejido de fibra de vidrio(2/2 Twill, y 8H Satin) y otro con fibra de carbono (8H Satin) . El envejecimiento se realizó manteniendo, durante diferentes periodos de tiempo, probetas en una cámara climática bajo unas determinadas condiciones de temperatura y humedad relativa. La determinación de la tenacidad a fractura interlaminar se realizó utilizando probetas de modos I (DCB) y II (ENF). El análisis realizado consistió en poner de manifiesto los diferentes mecanismos de rotura a fractura que se generan tras someter las probetas a la exposición higrotérmica. De los resultados de los ensayos se concluye un diferente comportamiento a fractura según el refuerzo existente y también a igual refuerzo, según la trama del tejido.

As part of a large human biomonitoring study, we conducted occupational monitoring in a glass fibre factory in Slovakia. Shopfloor workers (n = 80), with a matched group of administrators in the same factory (n = 36), were monitored for exposure to glass fibres and to polycyclic aromatic hydrocarbons (PAHs). The impact of occupational exposure on chromosomal aberrations, DNA damage and DNA repair, immunomodulatory markers, and the role of nutritional and lifestyle factors, as well as the effect of polymorphisms in metabolic and DNA repair genes on genetic stability, were investigated. The (enzyme-modified) comet assay was employed to measure DNA strand breaks (SBs) and apurinic sites, oxidised and alkylated bases. Antioxidant status was estimated by resistance to H 2 O 2 -induced DNA damage. Base excision repair capacity was measured with an in vitro assay (based on the comet assay). Exposure of workers to fibres was low, but still was associated with higher levels of SBs, and SBs plus oxidised bases, and higher sensitivity to H 2 O 2 . Multivariate analysis showed that exposure increased the risk of high levels of SBs by 20%. DNA damage was influenced by antioxidant enzymes catalase and glutathione S-transferase (measured in blood). DNA repair capacity was inversely correlated with DNA damage and positively with antioxidant status. An inverse correlation was found between DNA base oxidation and the percentage of eosinophils (involved in the inflammatory response) in peripheral blood of both exposed and reference groups. Genotypes of XRCC1 variants rs3213245 and rs25487 significantly decreased the risk of high levels of base oxidation, to 0.50 (p = 0.001) and 0.59 (p = 0.001), respectively. Increases in DNA damage owing to glass fibre exposure were significant but modest, and no increases were seen in chromosome aberrations or micronuclei. However, it is of concern that even low levels of exposure to these fibres can cause significant genetic damage., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 The Authors. Published by Elsevier B.V. All rights reserved.)

Tracking trace amounts of analytes directly from low volumes of complex biological samples remains an ongoing challenge in precision diagnostics, as the commonly used immunosorbent assays have limited sensitivity. Herein, a CRISPR/Cas12a assisted on-fibre immunosensor (CAFI) was developed based on an antibody-analyte-aptamer sandwich structure, in which a single strand DNA aptamer was applied to detect the analyte while triggering the CRISPR/Cas12a fluorescent detection system to amplify the analyte signal. This novel CAFI biosensing system was fabricated on a glass fibre surface with an antifouling PEG polymer brush modified for the detection of a spectrum of small molecules from complex media. In comparison with a conventional ELISA system, CAFI has a 1,000-fold higher sensitivity with the limit of detection for IFN-γ down to 1 fg mL -1 (58.8 aM). It also has a tuneable linear detection range that can be easily adjusted within the range 1 fg mL -1 to 100 pg mL -1 (5 orders of magnitude), meeting the requirements of the demanding diagnostic scenarios. CAFI has successfully been demonstrated by detecting IFN-γ from a diverse complex biological sample type, including human serum, whole blood, perspiration, and saliva. Moreover, CAFI is applicable for the detection of other analytes by simply modifying the capture antibody and detection aptamer, demonstrated here with insulin. All these superior capabilities of CAFI make it a suitable technology to measure proteins in low (100 μL) volume complex biological samples., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier B.V. All rights reserved.)

The proportion of composites, mainly glass and carbon fibre-reinforced polymers (FRP) in the material cycle have been increasing for years in many sectors. Landfilling of FRP waste is forbidden and recycling is still an unsolved issue. Aim of this paper is the investigation of a feasible reuse of FRP as reinforcement in concrete as shredded material or as thermally recovered plain carbon fibres. A huge amount of glass fibre polymer waste is generated in the wind energy sector and shows low alkaline resistance which is not directly applicable as a reinforcement in alkaline concrete without any surface protection. Therefore, different surface treatments were conducted: on the one hand the aim is to protect FRP fragments in concrete and on the other hand to improve the adhesion. The results of pull-out tests show that a sanded surface of glass fibre polymers increases the averaged maximum shear strength by 16 %. Investigation of the influence of different volume contents (0.25, 0.5, 1 and 2 Vol.-%) of recycled, pyrolized carbon fibres with a varying fibre length show a maximum flexural strength at 1 Vol.-% in bending tests on fibre reinforced concrete. Compared to plain concrete an increase of +111 % can be observed., Competing Interests: Declaration of Competing Interest None., (Copyright © 2019 Elsevier B.V. All rights reserved.)