Search Results (5,359)

The study aims to assess the potential of recycled carbon fibers recovered from end-of-life wind turbine blades as a sustainable reinforcement material for concrete and to establish correlations between fiber parameters and the mechanical behavior of fiber-reinforced concrete. The research focuses on how fiber length, content, and cement type affect the residual flexural strength and cracking behavior of FRC. The experimental program included 48 concrete mix series with varying fibre lengths (25, 38, and 50 mm), dosages (0, 2, 4, and 8 kg/m³), cement types (CEM I 42.5 and CEM II 42.5R/A-V), and water-to-cement ratios (0.50 and 0.40). Mechanical properties such as compressive strength, tensile strength, modulus of elasticity, and residual flexural strength were evaluated. Notched beams underwent three-point bending tests, and the progression of cracks was tracked using the digital image correlation method. The analysis revealed that enhancing both the fiber content and length generally bolstered the toughness and post-cracking characteristics of concrete, with a notable effect observed for fibers ranging from 38 to 50 mm in length when used at a dosage of 8 kg/m³. However, the effects depend on the fiber recovery technology and the base concrete strength, which may influence the results and should be considered as a limitation of this study. Full article

The research empirically evaluates ancient earth construction techniques through the analysis of archaeological adobe samples from Tell Zurghul/Nigin, south-eastern Iraq, dating from the mid-5th to mid-3rd millennium BCE. Simple, non-standardised empirical field tests were employed to obtain preliminary material characterisations, valuable for pilot assessments and gaining further significance when compared with quantitative analytical results. Their application evaluates the functionality of these tests while integrating archaeological insights with material science, underscoring the importance of multidisciplinary collaboration in earthen heritage conservation. Sixteen samples—fifteen archaeological and one modern—were analysed to assess raw material composition, grain size, clay behaviour, organic content, cohesion in wet and dry states, and surface adhesion. Results demonstrate notable homogeneity in material composition across the time span, primarily fine sands with minimal clay or silt. This suggests favourable drainage, minimal shrinkage, and reduced cracking but limited cohesion, implying a potential need for stabilisers such as plastic clays or fibres in construction. These findings inform conservative strategies for the preservation and restoration of earthen structures at the site. Full article

This study investigates the elastic properties of bio-epoxy composites reinforced with natural fibres (flax, hemp) and synthetic fibres (S-glass), with particular focus on the effect of the fibre volume fraction (VF) ranging from 10% to 70%. Three-dimensional representative volume element (RVE) models were developed for single-fibre, hybrid, and multi-fibre systems. The mean-field homogenisation (MF) approach, based on the Mori–Tanaka scheme, and finite element analysis (FEA) with periodic boundary conditions were employed to predict the effective elastic properties, including longitudinal, transverse, and shear moduli, as well as Poisson’s ratio. These numerical predictions were validated against analytical models, including the rule of mixtures, Chamis, and composite cylinder assemblage (CCA) methods. The results demonstrate that increasing the VF enhances longitudinal, transverse, and shear moduli while reducing Poisson’s ratio in natural fibre composites. The good agreement between numerical, semi-analytical, and analytical methods validates the 3D RVE models as useful tools for predicting the properties of multi-hybrid natural fibre composites, supporting their design for lightweight structural applications. Full article

This review critically surveys the emerging integration of Surface-Enhanced Raman Scattering (SERS) with photonic-crystal fibers (PCFs) for chemical and biological detection, an area still scarce in the literature. SERS exploits electromagnetic and chemical enhancement to overcome the intrinsic weakness of Raman scattering, while PCF offers low transmission loss and a strong evanescent field that further amplify the signal. The structural designs of PCF, encompassing solid-core and hollow-core variants, are discussed and their respective advantages in different sensing scenarios are presented. Applications in chemical detection, biomedicine, and explosive identification are detailed, demonstrating the versatility and potential of PCF-SERS sensors. Future efforts will focus on robust PCF geometries that guarantee stable and reproducible signals, AI-driven spectral algorithms, hybrid fibre architectures and scalable manufacturing. These advances are expected to translate PCF-SERS from bench-top demonstrations to routine deployment in environmental monitoring, clinical diagnostics and food-safety control. Full article

Oedema is a common clinical finding in critically ill neonates and may reflect systemic illness such as congestive heart failure, hepatic cirrhosis, nephrotic syndrome, sepsis, and acute kidney injury. Oedema is characterised by tissue swelling due to water accumulation in the interstitial space. Currently, the gold standard in clinical practice is visual assessment, which is subjective and limited in accuracy. Alternative methods, such as ultrasound and bioimpedance, have been explored; however, they are unsuitable in neonates and do not provide direct water quantification. Near-infrared spectroscopy (NIRS) is a non-invasive optical method that could measure water content through light interaction between near-infrared light and OH particles within the tissue. This study validated NIRS for oedema assessment using an ex vivo porcine skin model, where controlled oedema was induced by phosphate-buffered saline (PBS) injection. Continuous spectroscopic data were collected via optical fibres positioned perpendicularly and parallel to the tissue. Regression models were developed and evaluated using the spectral data, with partial least squares (PLS) regression outperforming ridge regression (RR) and support vector regression (SVR). Notably, spectra acquired in the parallel configuration yielded superior results (R² = 0.97, RMSE = 0.15). These findings support the potential of NIRS as a reliable, quantitative tool for neonatal oedema assessment. Full article

Background/Objectives: Shift work and chronotype influence timing and type of food consumed, yet their combined influence is unclear. This study determined differences between temporal patterns of eating (times of first (FEO), last (LEO), and largest eating occasions (LarEO), duration of eating window (DEW), eating frequency) and nutrient intake of night shift workers on and off shift and the additional influence of chronotype. Methods: Participants (46.6 ± 10.2 years, BMI: 33.9 ± 5.6 kg/m², male/female: 57/72) completed work/sleep/food diaries, and the Composite Scale of Morningness. Dietary profiles were characterized by day type as follows: morning shift (MS), 1st night shift (1stNS), subsequent night shifts (SNS), 1st day off after night shifts (1stDONS), or other days off (DO). Results: Across day types, there were significant differences in FEO (p < 0.001), LEO (p < 0.001), LarEO (p = 0.025), DEW (p < 0.001), eating frequency (p = 0.003), total energy (p = 0.022), and fibre intake (p < 0.001). Compared to MS, all night shifts had later FEO, LEO, and LarEO; 1stNS had longer DEW and higher fibre but no differences in frequency, energy, and macronutrient intake. Greater morningness was associated with earlier FEO, LEO, LarEO, and lower %energy from fat and saturated fat. Effect of chronotype on temporal eating patterns was not different across day types; there was a significant, positive relationship between morningness and %energy from carbohydrate (%Energy_CHO) on MS (p = 0.004) and 1stDONS (p = 0.040). Conclusions: Dietary habits of night shift workers vary by shift schedule and degree of morningness. Further studies will confirm if shift schedule is more influential than chronotype on shift workers’ dietary habits. Full article

Intake of anthocyanin-rich blackcurrant extract showed muscle fibre-type specific force responses during fatigue development from combined use of voluntary maximal isometric contractions and electrically evoked twitch contractions of the m. quadriceps femoris. In the present exploratory study, we examined the fibre-type specific effects by blackcurrant extract on high-intensity intermittent treadmill running performance to exhaustion. Active males (n = 16, age: 23 ± 3 years, height: 179 ± 5 cm, body mass: 79 ± 3 kg, $\dot{V}$O_2max: 55.3 ± 5.0 mL·kg⁻¹·min⁻¹) completed a fatiguing protocol with 16 voluntary maximal isometric contractions to predict muscle fibre typology. The high-intensity intermittent running protocol was completed twice following a 7-day intake of blackcurrant extract (210 mg anthocyanins per day) and twice following a placebo (PL) in a randomized, double blind, crossover design. Heart rate and lactate were recorded at exhaustion. Data were averaged for each condition. There were no significant correlations between the percentage force decline by the repeated isometric contractions (mean ± SD: 29.3 ± 12.4%) and total and high-intensity running distance. Participants were categorized into a predominant muscle fibre type I (slow-twitch, n = 3 with the lowest isometric force decline: 12 ± 9%) and type II typology (fast-twitch, n = 3 with the highest isometric force decline: 46 ± 10%). Only the individuals with a predominant type I fibre typology improved the total running and high-intensity running distance by 17 ± 12% and 15 ± 11%. At exhaustion, there were no differences between individuals with a type I or II fibre typology for heart rate and lactate. These exploratory results suggest that the ergogenic potential of anthocyanin-rich blackcurrant extract on high-intensity intermittent exercise may depend on muscle fibre type, though larger and more robust studies are needed to confirm this observation. Future work will establish whether our exploratory results contributed to our understanding of the underpinning of inter-individual responses to the intake of anthocyanin-rich nutritional ergogenic aids. Full article

The natural frequencies and damping characterisation of a new aerospace grade composite material were investigated using a modified impulse method combined with the half power bandwidth method, which is applicable to the structures with a low damping. The composite material of interest was unidirectional carbon fibre reinforced plastic. The tests were carried out with three identical square 4.6 mm thick plates consisting of 24 plies. The composite plates were clamped along one edge in a SignalForce shaker, which applied a sinusoidal signal generated by the signal conditioner exiting the bending modes of the plates. Laser vibrometer measurements were taken at three points on the free end so that different vibrational modes could be obtained: one measurement was taken on the longitudinal symmetry plane with the other two 35 mm on either side of the symmetry plane. The acceleration of the clamp was also recorded and integrated twice to calculate its displacement, which was then subtracted from the free end displacement. Two material orientations were tested, and the first four natural frequencies were obtained in the test. Damping was determined by the half-power bandwidth method. A linear relationship between the loss factors and frequency was observed for the first two modes but not for the other two modes, which may be related to the coupling of the modes of the plate and the shaker. The experiment was also modelled by using the Finite Element Method (FEM) and implicit solver of LS Dyna, where the simulation results for the first two modes were within 15% of the experimental results. The novelty of this paper lies in the presentation of new experimental data for the natural frequencies and damping coefficients of a newly developed composite material intended for the vibration analysis of rotating components. Full article

The increasing production of fruit and vegetable by-products from the food processing industry presents both environmental challenges and opportunities for valorisation as sources of bioactive compounds. These by-products, including peels, seeds, pomace, and leaves, are rich in polyphenols, carotenoids, dietary fibres, glucosinolates, phytosterols, and essential oils, which exhibit antioxidant, anti-inflammatory, antimicrobial, and prebiotic activities. Recent advances in green extraction technologies, including ultrasound-, microwave-, supercritical fluid-, and cold plasma-assisted extraction, allow for an efficient and sustainable recovery of these compounds, while preserving their bioactivity. Incorporation of by-product-derived extracts into functional foods and nutraceuticals offers health-promoting benefits and supports circular bioeconomy strategies. However, challenges remain in standardisation, safety assessment, and regulatory approval, among others. This review summarises current progress and outlines future directions for the sustainable utilisation of fruit and vegetable by-products in health-oriented applications. Full article

The long-term viscoelastic behaviour of epoxy matrices in Carbon Fibre-Reinforced Polymer (CFRP) tendons can lead to creep strains which must be accurately quantified to improve the current necessarily conservative design guidelines for bridge applications. However, the task of experimentally capturing such strains—typically in the range of 0.05%—requires sensors with reliable long-term accuracy and precision. This study investigates creep in CFRP tendons subjected to sustained tensile loading at 80% (for 7 days) and 88% (for 22 h) of their ultimate tensile strength. Four strain sensing techniques were employed to capture the creep strains of the CFRP tendons: bonded metal foil strain gauges, a contact extensometer, Digital Image Correlation, and distributed fibre optic strain sensing. This work precisely quantifies—for the first time in CFRP creep testing—the influence of experimental artefacts on the performance of the strain sensors, including test rig movement, temperature sensitivity, and localised surface inhomogeneities. Results reveal significant measurement distortions: the extensometer recorded strain increases of 250% during tendon slip, while distributed fibre optics detected localised strain peaks reaching 150% of the surface average. These findings demonstrate that sensor-induced noise can substantially contaminate creep strain data, underscoring the critical need for rigorous experimental protocols and thorough sensor validation in CFRP creep studies. Full article

This study investigates the impact of using coagulants on the removal of microplastics (MPs) from wastewater and tap water. Before the settling step, coagulants commonly used in water treatment (FeCl₃ or Al₂(SO₄)₃) were added at different concentrations to samples taken from an activated sludge reactor and tap water. MPs initially contained in the water samples were chemically and physically characterized, resulting in most of them being fibres smaller than 500 μm, in both media. The use of coagulants improved MPs removal, and the best results were obtained with the aluminum salt, which allowed removal efficiencies of 43% and 62% for tap water and wastewater, respectively. These results demonstrated the potential of coagulants to improve the removal of MPs in treated waters and wastewaters. However, the necessary concentration of the assayed coagulants was quite high, highlighting the interest in investigating their combination with coagulant aids, such as organic polyelectrolytes, which might allow for reduced doses. Full article

The continuous rise in textile waste, driven by global population growth and the proliferation of fast fashion, has raised concerns about its efficient recycling and sustainable management. This study aims to assess the feasibility of recycling textile waste by incorporating recycled cotton fibres as reinforcement in polypropylene-based composites. Specifically, it examines the mechanical, thermal, and chemical properties of composites composed of 50% recycled polypropylene and 50% reinforcing fibres (either virgin or recycled cotton), with and without the addition of 5% maleic anhydride-grafted polypropylene as a compatibilizer to enhance fibre-matrix adhesion. Although the use of recycled cotton as reinforcement reduced the mechanical properties of the composite material, the addition of 5% compatibilizer improved these properties to levels comparable to those of composite reinforced with virgin cotton. Full article

Expansive clay soils present major challenges for infrastructure due to their high swelling potential and low bearing capacity. While conventional stabilisers, such as lime and Ordinary Portland Cement (OPC), are effective, they are environmentally unsustainable due to their high carbon footprint. This study examines the potential of shredded recycled polyethene terephthalate (PET) fibres as a low-carbon alternative for stabilising high-plasticity clays. PET fibres were incorporated at dosages ranging from 0% to 1.2% by dry weight, and their influence on compaction characteristics, unconfined compressive strength (UCS), California Bearing Ratio (CBR), swelling behaviour, and microstructure was evaluated through laboratory testing and Scanning Electron Microscopy (SEM). Among the tested mixes, the 1.0% PET content exhibited the highest measured performance, resulting in a 37% increase in UCS, a 125% enhancement in unsoaked CBR, more than a two-fold increase in soaked CBR, and a 15% reduction in the Differential Free Swell Index (DFSI). SEM analysis indicated the formation of a three-dimensional fibre matrix, which improved particle interlock and reduced microcrack propagation. However, higher fibre dosages caused agglomeration and macrovoid formation, which adversely affected performance. Overall, the findings suggest that the inclusion of PET fibres can enhance both geotechnical and environmental performance, providing a sustainable stabilisation strategy that utilises plastic waste while reducing reliance on OPC. Full article

Increasing traffic volumes, heavier axle loads, and the growing frequency of premature pavement distress pose major challenges for modern road infrastructure. In many regions, asphalt pavements experience early rutting, cracking, and moisture-induced damage, underscoring the need for improved material performance and longer service life. Reinforcing fibres are increasingly used to enhance asphalt mixture properties, with aramid fibres recognised for their superior mechanical and thermal stability. This study evaluates the effect of FlexForce (FF) fibres on the mechanical and fracture behaviour of two dense-graded asphalt concretes, AC 16 surf and AC 16 bin, produced with different binders and fibre dosages (0.02% and 0.04% by mixture weight). Laboratory tests, including indirect tensile strength ratio (ITSR), indirect tensile stiffness modulus (IT-CY), crack propagation resistance, and dynamic modulus measurements, were performed to assess moisture susceptibility, stiffness, and viscoelastic behaviour. The results showed that fibre addition had little effect on compactability and stiffness under standard conditions but improved temperature stability and stiffness at elevated temperatures, particularly when used with polymer-modified binders. Moisture resistance decreased slightly, while fracture performance improved moderately at intermediate temperatures. Overall, low fibre dosages (~0.02%) provided the most balanced performance, indicating that the mechanical benefits of aramid reinforcement depend strongly on binder rheology, temperature, and interfacial compatibility. These findings contribute to optimising fibre dosage and binder selection for aramid-reinforced asphalt layers in practice. Full article

Disposable diapers contribute significantly to municipal solid waste, with non-biodegradable polymers such as low-density polyethylene (LDPE) persisting in landfills for centuries. Biodegradable alternatives, including polylactic acid (PLA), poly(butylene adipate-co-terephthalate) (PBAT), bamboo, and organic cotton, offer reduced environmental persistence, although challenges remain regarding cost, mechanical performance, and scalability. This review synthesizes current literature on these materials, highlighting their properties, biodegradation mechanisms, environmental performance, and commercial feasibility. In addition, we examine emerging biodegradable superabsorbent polymers (SAPs), such as polysaccharide-based hydrogels, chitosan, and nanocellulose, essential for fully compostable diapers. Our review uniquely integrates material performance, tropical high-humidity degradation, cost considerations, and consumer acceptance, providing insights into both technological advances and barriers to adoption. Key challenges include high production costs, supply chain limitations, and maintaining performance parity with conventional diapers. Finally, we discuss sustainable waste management strategies, including industrial composting, and identify future research directions focused on optimizing biopolymer properties, safety, and life-cycle impacts. This synthesis informs researchers, industry stakeholders, and policymakers seeking to advance environmentally responsible diaper products. Full article