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This study analyses the microplastics in the sediment of areas surrounding shipwrecks on the Continental Shelf of Pernambuco, North eastern Brazil. The sediment collection was carried out around six wrecks. Flotation methodology was used to separate the possible microplastics from the sediment. Microplastics were classified by type and colour. Of the 6 shipwrecks analysed, 413 microplastic items were identified, with nylon fibre predominating. Fibres of blue colour were the most frequent, totalling 48.4%. The presence of microplastics in shipwrecks shows that this environment, even far from the coast, is subject to human activity. The accumulation of microplastics in the sediments surrounding the shipwrecks may pose a risk to marine life. [ABSTRACT FROM AUTHOR]

The research described in this paper identifies how the use of three-dimensional (3D) unwelded fibre reinforcement can provide protection against back-face spalling in the case of damage caused by impact, and contributes to understanding how such material specification can carry significant long-term benefits. When subjected to ballistic impact or explosion, reinforced concrete suffers back-face spalling caused by compressive stress waves, resulting in projectiles that can cause injury and collateral damage. This conceptual study seeks to reduce concrete projectiles and subsequent damage using 3D unwelded fibre-reinforcement. Conventional two-dimensional (2D) straight fibres rely on orientation and positioning for effective bridging of rupture planes, whereas 3D fibres benefit from inherent superiority of their orientation across a rupture plane. Twenty-five kilograms of 3D unwelded fibres (3DUWBL) and 2D fibres per m3 of concrete were used in the mix designs. Samples were tested for compressive strength, fibre pull-out, three-point and four-point flexural testing and ballistic impact. There was significant improvement in toughness and post-fracture control within the 3DUWBL specimens. The 3DUWBL fibres exceeded EN 14889 standards, outperforming the 2D fibre specimens, and controlled back-face spalling and reduced airborne projectiles in comparison to the 2D fibres. The study is limited to demonstrating proof of concept. The implication of these results will inform future research studies in this area. The results identify a current gap in research associated with 3D unwelded fibre use and the reduction of back-face spalling. 3D fibres overcome the significant failings of even dispersion and bond pull-out strength ordinarily associated with 2D fibres. This is due to the x y z orientation and omission of the welded connection. The implications are a reduction in manufacturing time and costs, making 3DUWBL fibres a more viable industry application. This research shows that 3D unwelded fibre reinforcement provides good resistance to back-face spalling of concrete elements when they are subjected to ballistic stresses. Such fibres are not currently commercially available, but they would be cheaper to produce, and their novel fibre shape provides enhanced post-crack toughness performance with the addition of lower variability, providing a lower-risk form of crack control. [ABSTRACT FROM AUTHOR]

This research proposes to include different percentages of recycled polypropylene (PP) fibers and polystyrene (PS) granules in the manufacture of concrete blocks. They are thermoplastic materials widely used in industry and are characterized by their lightness, their low thermal and electrical conductivity, and their low humidity absorption coefficient, factors that improve the efficiency of constructions. The results of this study show improvements in the mechanical behavior of the blocks with these plastic additives compared to the traditional ones, along with improvements in the structural behavior of the low (2-story) and medium-height (8-story) frames. [ABSTRACT FROM AUTHOR]

NiCoP transition metal phosphide has been recognized as a most promising candidate to alternate the noble metals in hydrogen evolution reaction. Herein, it is first time presented the facile preparation of NiCoP electrocatalyst in form of fibers with dominant 1D structure formed by needle-less electrospinning technology and finalized by defined heat treatment process. The study provides a precise method for the preparation of NiCoP or similar phosphide fibers, together with an experimental proof of their excellent electrocatalytic performance in alkali and acidic environments. The as-prepared fibrous NiCoP electrocatalyst sintered in air at 900 °C followed by sintering at 700 °C in Ar/H 2 exhibits low hydrogen evolution reaction overpotential (η 10) of 141 mV in alkali and 146 mV in acidic environment corresponding with low Tafel slopes of 53 and 97.8 mV/dec, respectively. The bimetallic phosphide also shows superior oxygen evolution reaction activity in alkaline medium 1 M KOH with satisfying durability in long-term stability tests. The highly innovative fibrous form of the material not only plays a significant role in regulation of the electronic structure and boosting the electrochemical active sites and thus the electrocatalytic performance in water splitting technology, but also allows tuning of the electrode electric conductivity, occurrence of the active sites probability and thus utilisation of the electrode, together with its permeability and mechanical stability. [Display omitted] • NiCoP fibers as innovative and efficient HER catalysts were prepared. • Needle-less spinning technology was used for preparation of the catalysts. • NiCoP fibers exhibit exceptional HER and OER activity in alkaline environment. • NiCoP fibers exhibits superior HER activity and stability in acidic environment. [ABSTRACT FROM AUTHOR]

Local defects in cellulose fibres, commonly referred to as microcompressions, increase the apparent strain to fracture in paper, an increasingly important parameter for products demanding stretch. This study presents an investigation into the origin of microcompressions by examining the behaviour of aspen wood under uniaxial compression applied along the grain, a process mimicking the action of a screw press and refiners during mechanical pulping. Using X-ray micro-computed tomography, a series of 10 tomograms with 30 µm of compressive deformation between images were acquired at 1.2 µm voxel size. For each tomogram, image analysis routines were developed to segment and label individual tracheids, vessel and ray elements, and track their motion between sequential frames. We classified the evolution of the axial trajectory of each element as either non-buckled or buckled, with a prominent presence of microcompression with axial deformations of less than 3%. We argue that microcompression precedes buckling. Significantly, we advance that localized deformation events (microcompressions, buckling, telescopic shortening) nucleate near vessel elements, and spread with increasing levels of compression; no particular structure appears to be immune to collapse. Finally, we liberated fibres in the compressed sample through chemical pulping and found that the damage occurring from compression was permanent. [ABSTRACT FROM AUTHOR]

Little is known about microplastics (MPs) in adult frogs. We investigated MPs in adult Common River Frogs (Amietia delalandii) from Potchefstroom, South Africa. Five kinds of samples were analysed: natural water, water used to rinse the skin, skin, intestine, and the remainder of the body (corpus). Tissues were digested. Microplastics occurred in all frogs and sample types (1128 MPs counted). Fibres were the most prevalent MP. Fibre lengths were between 28 and 4300 μm, either polyester or polyvinyl alcohol. MPs in skin were likely derived from the ambient, and MPs in the corpus from translocation via the skin. Fibres in tissues were significantly shorter in larger frogs, a phenomenon we provisionally assign to in situ biodegradation. Microplastics in frogs can potentially be transferred through the food web to higher trophic levels. This study provides the first evidence of MPs in adult frog tissues and avenues for further investigations. [ABSTRACT FROM AUTHOR]

The composite materials are fabricated by combining various ingredients to make higher material properties as required by various industries. The primary classification of composites is based on their build ingredients, such as binder, fibre, reinforcement and fillers. The characteristics of individual ingredients influenced the properties of composites. Further, friction materials are those composite materials efficiently used in vehicles' braking. Researchers have tried the various formulations of friction materials because it is very significant to study the mechanism and material characteristics due to the safety measures of vehicles. The current study examines the various brake composite materials' characteristics and their mechanical and tribological performance in this article. The tribological study includes the various terminologies used in friction and wear using pin-on-disc, dynamometer, field studies, etc. The effects of numerous elements impacting the wear of frictional materials are given, and the tribological performances of used friction materials are given the utmost attention. [ABSTRACT FROM AUTHOR]

Background and aim: The cardio-oesophageal sphincter that is located in close longitudinal proximity to the origin of the lesser curvature of the stomach has a unique pattern of external muscle fibres whose inner oblique layer would normally form an elongated sling and the middle partially circular layer would form a projecting clasp into the already existing muscular sling of the former congruently, which would result in the formation of an anatomical sphincter in that area that would normally be devoid of the external longitudinal muscle layer coat. Certain authors have disagreed with the notion of this standard literature and have proposed that the clasp and sling fibres need not necessarily be congruent and may even remain independent of each other with partial contributions from the longitudinal muscle layers as well that may arise tangentially in different populations, which may in turn contribute to reflux oesophagitis in that population. Hence, the clasp and sling fibre muscular patterns were observed in six formalin-embalmed cadavers at the department of anatomy in a tertiary care institute as part of routine dissections in series, and the findings were then reported. Findings: At the junction of the lesser curvature of the stomach with the oesophagus, all six cadavers showed a longitudinal sling pattern as opposed to the conventional oblique sling. The circular muscle layer was found to be merged with the outer longitudinal muscle layer to form the sling that pulled away from the clasp, resulting in a loss of congruency for the same. The clasp fibres, however, were found to be contributed by the inner oblique muscle layer. The conventional perpendicular or tangential merging of the clasp with the sling was not observed; instead, an obtuse, blunt angular merging of the clasp with the sling was observed. Discussion: The deviation of the sling from the clasp could indicate a lack of a proper fit between them at the cardio-oesophageal sphincter. The lack of robustness in the attachment of the clasp to the sling may possibly contribute to the diminished taut pull of the clasp in this subset of the population. These would be significant determinants for a predisposition to reflux oesophagitis and Barrett's oesophagus. [ABSTRACT FROM AUTHOR]

This paper presents a simple method of obtaining polyamide 6 fibres modified with acetanilide and copper ions. During the spinning of the fibres with the additives applied, a partial reduction of CuSO4 to Cu2+ and Cu+ ions occurs, which is observed as a change in the blue colour of the prepared polyamide granulate to the grey–brown colour of the formed fibres. CuMPs obtained as a result of the salt reduction should give the obtained fibres bioactive properties. Three types of microorganisms were selected to assess the microbiological activity of the obtained fibres, i.e., Gram-positive Staphylococcus aureus and Gram-negative Pseudomonas aeruginosa and Escherichia coli. The fibres have antibacterial activity against Gram-positive and Gram-negative bacteria. The largest inhibition zones were obtained for the Gram-positive bacteria Staphylococcus aureus, ranging from 1.5 to 4.5 mm, depending on the concentration of CuMPs. The morphology of the fibres' surfaces was examined by means of scanning electron microscopy (SEM) and optical microscopy (OM). The changes in the polymer structure chemistry are studied by Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, X-ray structure studies (WAXS and SAXS) and an energy-dispersive spectroscopy (EDS) analysis. The newly obtained bioactive polyamide fibres can be used in many areas, including medicine, clothing and environmental protection for the production of filters. [ABSTRACT FROM AUTHOR]

Copyright of Roads & Bridges / Drogi i Mosty is the property of Road & Bridge Research Institute and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

SiC fiber-reinforced matrix composites (SiC f /SiC) have limited applications because of the irradiation-induced shrinkage of SiC fibers; the fiber shrinkage mechanism is still not fully understood. In this study, we tried to clarify the effect of annealing temperature on the proportion of fiber shrinkage and swelling. SiC f /SiC was irradiated at 30 °C to 100 dpa, and the deterioration of mechanical properties was evaluated after irradiation. The compressive displacement of > 60% of the fibers before failure increased to more than 1.5 times that of the as-received specimen. Significant swelling was observed, indicating that the proportion of swelling was higher than that of shrinkage after irradiation. This can be attributed to the amorphization of SiC, and its amorphization threshold dose increased with decreasing grain boundary volume fraction. The findings of this study provide insights into the mechanism of irradiation-induced fiber amorphization and can be useful in developing improved SiC f /SiC. • Amorphization was observed in room-temperature-irradiated SiC fibers. • Different amorphization threshold doses were caused by differences in grain boundary volume fraction. • Volume expansion was observed in both the CVIed-SiC and SiC fibers. • The strength of the amorphous SiC fiber degraded. • The compressive displacement before failure significantly increased. [ABSTRACT FROM AUTHOR]

The use of fibres applied to concrete in order to improve its properties is widely known. Nowadays, research is not only focused on improving mechanical properties but also on the environmental implications. The aim of this research was a mechanical and environmental comparison between different types of fibres. For this purpose, commercial fibres of three materials were used: low carbon steel, modified polyolefins, and glass fibre. In order to improve the sustainability of the sector, we also analysed and compared the performance of using a waste product, such as fibres from machining operations on lathes. For the evaluation of the mechanical properties, compression and flexural tests were carried out. The results show that the use of low carbon steel fibres increases the flexural strength by 4.8%. At the environmental level, and in particular for impact categories such as the Global Warming Potential (GWP), lathe waste fibres prove to be the most suitable. For instance, compared to glass fibres, CO2 emissions are reduced by 14.39%. This is equivalent to a total of 38 kg CO2 emissions per m3 of reinforced concrete. In addition to avoiding the consumption of 482 MJ/m3 of fossil fuels, the results of the research indicate the feasibility of using waste fibres as a substitute for commercial fibres, contributing to an improved environmental balance without losing mechanical performance. [ABSTRACT FROM AUTHOR]

A new framework for the parametric reconstruction of curved fibres from glass fibre-reinforced composite X-ray computed tomography data is proposed. It allows us to detect fibres in a fibre-reinforced polymer sample from a low-dose, low resolution computed tomography scan. An efficient curve representation is then used for each detected fibre, of which the parameters are estimated directly from few 2D high-resolution projection images. The framework is validated on both simulated and real data of glass fibre-reinforced polymers. The generated results demonstrate that it is robust to noise and requires less than 10 high-resolution projections to obtain reasonable fibre estimates. The method can also improve upon existing estimation frameworks relying on full 3D scans. [ABSTRACT FROM AUTHOR]

The current study reviews the viability of various fibre-polymer composites and treatment techniques along with the intricacy involved in improving the rotational moulding process. It is a method used in the manufacturing of hollow plastic items free from stress. As the rotational moulding process has gained prominence in a variety of crucial applications in recent years, a detailed analysis of this technique is important. For this reason, an exhaustive review of various fibres and polymers used in rotational moulding along with different pre-treatment techniques for improving the processability has been carried out and categorised into three sections. The first section deals with the type of polymers which are used for the process along with their nature and suitability for rotational moulding. The second section deals with the study of different fibres that have been blended with the polymers. The last section of the review discusses the different fibre treatment techniques which can be used to improve polymer-fibre compatibility. From a wide range of polymers used, it has been observed that the ease of processability of linear low-density polyethylene makes it the most suitable grade for rotational moulding. It can also be noticed that artificial fibres provide good mechanical properties compared to natural fibres but being eco-friendly and having low cost, natural fibres are more vital in the application. It is evident from the review that fibre pre-treatment enhances the polymer-fibre compatibility which improves the mechanical properties of the rotationally moulded products. Further, it can be concluded from the literature review that an adequate variety of polymer and fibre along with fibre treatment techniques can make an important contribution to the rotational moulding process. [ABSTRACT FROM AUTHOR]

Alternative eco-friendly and sustainable construction methods are being developed to address growing infrastructure demands, which is a promising field of study. The development of substitute concrete binders is required to alleviate the environmental consequences of Portland cement. Geopolymers are very promising low-carbon, cement-free composite materials with superior mechanical and serviceability properties, compared to Ordinary Portland Cement (OPC) based construction materials. These quasi-brittle inorganic composites, which employ an "alkali activating solution" as a binder agent and industrial waste with greater alumina and silica content as its base material, can have their ductility enhanced by utilising the proper reinforcing elements, ideally "fibres". By analysing prior investigations, this paper explains and shows that Fibre Reinforced Geopolymer Concrete (FRGPC) possesses excellent thermal stability, low weight, and decreased shrinking properties. Thus, it is strongly predicted that fibre-reinforced geopolymers will innovate quickly. This research also discusses the history of FRGPC and its fresh and hardened properties. Lightweight Geopolymer Concrete (GPC) absorption of moisture content and thermomechanical properties formed from Fly ash (FA), Sodium Hydroxide (NaOH), and Sodium Silicate (Na2SiO3) solutions, as well as fibres, are evaluated experimentally and discussed. Additionally, extending fibre measures become advantageous by enhancing the instance's long-term shrinking performance. Compared to non-fibrous composites, adding more fibre to the composite often strengthens its mechanical properties. The outcome of this review study demonstrates the mechanical features of FRGPC, including density, compressive strength, split tensile strength, and flexural strength, as well as its microstructural properties. [ABSTRACT FROM AUTHOR]

Researchers aim to produce sustainable insulation materials using lignocellulose fibres (natural plant fibres). Lignocellulose fibres are readily available, biodegradable, and low-cost materials for insulation. However, these materials are formulated as composites and not as fibres alone. Thus, the thermal properties of these composites depend on the volume fraction of each phase. The evaluation of thermal conductivity can be followed by experimental, analytical, and numerical methods. Numerical and analytical methods are convenient investigational methods; they are more cost-effective, have a higher degree of flexibility in design enhancement, and are faster methods of analysing results than the experimental method. The thermal conductivity value of each phase should be used to analyse the thermal properties of composite materials. However, there is no specific method to determine the thermal conductivity of natural fibres. Therefore, this work suggests a new method to find the thermal conductivity of coir fibres. The method follows the inverse calculation of the analytical methods to find the thermal conductivity of coir fibres, and the substitution values for the equations will be determined by an experimental method. The two-phase composite was fabricated by coir fibres and epoxy with different volume fractions. Next, the thermal conductivity was measured for the fabricated composite and epoxy using the hot disk method. Finally, the transverse thermal conductivity of the fibre was calculated using available analytical models namely, the Rule of mixture, Maxwell's model, Rayleigh's model, and the Lewis-Nielsen model. The thermal conductivity value determined was 0.3058 W/mK. The results were validated through numerical modelling. The thermal conductivity of fibres was determined using a binderless compacted fibre disk, and the obtained value was 0.2797 W/mK. This value was correlated with the results obtained with the analytical and numerical methods. [ABSTRACT FROM AUTHOR]

Natural fiber composites are becoming an alternate material to synthetic fiber composites, and the use of eggshell bio-filler has been explored in polymer composites as environmental protection. Jute, coir, and sisal fibers were utilized in this research to make composites out of natural fibers. Polymer composites were made using epoxy resin with different amounts of eggshell powder (ESP) as fillers (2%, 4%, 6%, 8%, and 10% of weight). The mechanical and biodegradability properties of the synthesized composites were investigated. The testing results showed that composites with an optimum percentage of 6% ESP as filler improved mechanical characteristics significantly in all three fiber composites. Among the three fibers, coir fiber with 6% ESP added showed a substantial increase in tensile, flexural, impact, and hardness strength properties by 34.64%, 48.50%, 33.33%, and 35.03%, respectively. In addition, the percentage weight loss of coir fiber composites at 9 weeks is noteworthy in terms of biodegradability testing. As a result, epoxy composites containing eggshell fillers could be employed in applications requiring better tensile, flexural, impact, and hardness strength. [ABSTRACT FROM AUTHOR]

Shear bearing behaviour of UHPFRC beams with compact cross‐section The shear bearing behaviour of ultra‐high performance fibre‐reinforced concrete (UHPFRC) beams differs depending on the shape of the cross‐section. Beams with I‐shaped cross‐section typically fail in shear tension of the thin web, while beams with compact cross‐section show diagonal tension failure. Thus, design approaches, which superimpose the shear resistance of a member without shear reinforcement, the effect of prestressing as well as the bearing mechanisms of stirrups and fibres, may not be equally applicable to both types of cross‐section. The aim of the present study was to investigate the shear bearing behaviour of UHPFRC beams with compact cross‐section and, in particular, the influence of fibre volume fraction and level of prestressing on the development of the critical shear crack and the shear resistance. To this, 22 shear tests were carried out. Crack initiation and propagation were monitored using digital image correlation. A clear influence of fibre volume fraction and level of prestressing on the shear cracking load could be observed in the tests. The test specimens without prestressing mainly showed typical diagonal tension failure, while for the prestressed test specimens the concrete compression zone failed under combined bending and shearing stress. Based on the results, an additive design approach was verified. It provides a conservative estimate of the shear cracking load for all tests. [ABSTRACT FROM AUTHOR]

SiC fiber oxidation is a potential factor limiting the operating temperature of SiC f /SiC composites owing to the strength degradation after oxidation. Herein, we fabricated 1-μm-diameter pillars at the core of the fiber cross-sectional surface after SiO 2 removal to eliminate surface effects caused by external oxidation. The fiber strength significantly decreased during the first hour of oxidation in dried air at 1400 °C, but this deterioration became less pronounced after 10 h. Simultaneously, the oxidation lowered the Young's modulus and Weibull modulus. Oxidation considerably increased the porosity and the alterations in the mechanical behavior were primarily caused by the variations in porosity. Oxidation-induced pores were frequently detected at the fiber core and were partially filled with SiO 2. Compared with those of the as-received fibers, O impurities in the oxidized fiber core were significantly reduced. Thus, the fiber strength was potentially degraded by the internal oxidation reaction between residual C and O. • SiC fibers transformed from dense to porous after oxidation. • Significant increase in porosity influenced the mechanical behavior of the fibers. • Strength of SiC fibers was evaluated by micropillar compression tests. • The strength degradation of SiC fibers was potentially caused by internal oxidation. [ABSTRACT FROM AUTHOR]

This publication summarises the current state of knowledge and technology on the possibilities and limitations of using mineral and synthetic fillers in the field of 3D printing of thermoplastics. FDM technology can be perceived as a miniaturised variation of conventional extrusion processing (a microextrusion process). However, scaling the process down has an undoubtful drawback of significantly reducing the extrudate diameter (often by a factor of ≈20–30). Therefore, the results produced under conventional extrusion processing cannot be simply translated to processes run with the application of FDM technology. With that in mind, discussing the latest findings in composite materials preparation and application in FDM 3D printing was necessary. [ABSTRACT FROM AUTHOR]

Fibre is one of the most popular additives in hot mix asphalt (HMA). However, there are few research studies about the application of fibres in cold recycled mixture with asphalt emulsion. In this study, five popular fibres are introduced to the emulsion recycled mixture, including polyester fibre, polypropylene (PP) fibre, polyacrylonitrile (PAN) fibre, lignin fibre, and basalt fibre. The optimum pre-mixing water (OPW) content, optimum emulsion content (OEC) and optimum fibre content of recycled mixtures reinforced by fibres are determined. The indirect tensile strength (ITS), moisture susceptibility, bending cracking at low temperature, rutting and fatigue life of mixtures with these fibres are investigated. The test results indicate that the OPW and OEC of recycled mixture are influenced by types and contents of fibres. Although different fibres lead to obviously different ITS values, the optimum content for each fibre is near 0.3% by weight of RAP. All five fibres improve the performance properties of the emulsion recycled mixture. The improved percentages depend on the type of fibres. Polyester fibre has higher improvement on fatigue life than the other fibres. Therefore, polyester fibre is recommended as the most effective fibre to improve the emulsion recycled mixture. [ABSTRACT FROM AUTHOR]

Soil-cement mixtures reinforced with fibres are an alternative method of chemical soil stabilisation in which the inherent disadvantage of low or no tensile or flexural strength is overcome by incorporating fibres. These mixtures require a significant amount of time and resources for comprehensive laboratory characterisation, because a considerable number of parameters are involved. Therefore, the implementation of a Machine Learning (ML) approach provides an alternative way to predict the mechanical properties of soil-cement mixtures reinforced with fibres. In this study, Artificial Neural Networks (ANNs), Support Vector Machines (SVMs), Random Forest (RF), and Multiple Regression (MR) algorithms were trained for predicting the elastic modulus of soil-cement mixtures reinforced with fibres. For ML algorithms training, a dataset of 121 records was used, comprising 16 properties of the composite material (soil, binder, and fibres). ANN and RF showed a promising determination coefficient (R2 ≥ 0.93) on elastic modulus prediction. Moreover, the results of the proposed models are consistent with the findings that the fibre and binder content have a significant effect on the elastic modulus. [ABSTRACT FROM AUTHOR]

The structure and mechanical properties of an injection-moulded short glass fibre (GF)-reinforced polymer composite were analysed through simulation methods. Fibre orientation, which evolves during the production of a thick-walled automotive part, was determined with an injection moulding simulation. Next, using the material model for the injected product, the force that resulted from the given deformation was determined with finite element software. To validate the simulation results, the examined products were manufactured with 30% reinforced GF, and then measurements were carried out. The validation of the fibre orientation tensor was achieved with optical microscope images, while the validation of the finite element, which analysed the flexural tests, was carried out through a comparison of flexural rigidity. The aim of the project was to verify the reliability of multi-stage finite element software. According to the results, in the case of a thick-walled GF-reinforced product, it was demonstrated that the integration of a different finite element software could be used reliably. [ABSTRACT FROM AUTHOR]

The proper disposal of used rubber tires has emerged as a primary concern for the environment all over the globe. Millions of tires are thrown away, buried and discarded every year, posing a major environmental concern owing to their slow decomposition. As a result, it is advantageous to use recycled waste rubber aggregates as an additional building resource. Recycling crushed rubber would lead to a long-term solution to the problem of decreasing natural aggregate resources while conserving the environment. This study examines the impact strength variability and reliability of preplaced aggregate concrete containing crumped rubber and fibres. Ten different mixtures were prepared by replacing natural aggregate with crumped rubber (5, 10, 15 and 20%). The crumped rubber was pretreated by the water with sodium hydroxide dilution for 30 min before usage. Hooked-end steel fibres were used at a dosage of 1.5%. The compressive strength, impact strength, impact ductility index and failure pattern were examined and discussed. In addition, a statistical method called Weibull distribution is used to analyze the scattered experimental results. The results showed that when the crumb rubber content was raised, the retained first cracking and failure impact numbers increased. As a result of substituting crumb rubber for 20% of the coarse aggregate in plain and fibrous mixes, the percentage development in first crack and failure was between 33% and 76% and 75% to 129%, respectively. [ABSTRACT FROM AUTHOR]

Tendon is a fibrous connective tissue where the fibres as biophysical cues are key regulators to regenerate injured tendon. However, electrospun fibres are often mechanically insufficient for the tendon application. Here, we reported a method by using rough polymer surface as the reinforcement of fibres to promote surface fibre deposition and integration during electrospinning. Results showed that the addition of polymer surface with open-pore topography significantly improved the deposition of fibres. The as-fabricated fibre topography was found to couple with improved surface hydrophilicity, higher crystallinity, and mechanical properties including both the maximum force and extension upon receiving elastic and plastic deformations. Seeding with TCSs, the fibre topography showed good cell compatibility and could be able to support F-actin cytoskeleton expression with the building of tendon cell interconnection. This work could have insights into the design of mechanically enhanced fibre topography for tendon tissue regeneration. [ABSTRACT FROM AUTHOR]

Carbon fibres are widely used in modern industrial applications as they are high-strength, light in weight and more reliable than other materials. The increase in the usage of carbon fibres has led to the production of a significant amount of waste. This has become a global issue because valuable carbon fibre waste ends up in landfill. A few initiatives have been undertaken by several researchers to recycle carbon fibre waste; however, the properties of this recycled material are expected to be worse than those of virgin carbon fibre. The incorporation of polymers, nanoparticles and other hybrid materials could enhance the overall properties of recycled carbon fibre waste. However, the degradation of fibre composites is expected to occur when the material is exposed to certain conditions and environments. The study of fibre composite degradation is crucial to enhance their properties, strength, safety and durability for future applications. [ABSTRACT FROM AUTHOR]

Copyright of Romanian Journal of Materials / Revista Romana de Materiale is the property of Foundation for Materials Science & Engineering Serban Solacolu and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Recycled Aggregate Concrete (RAC) has attracted considerable attention for its potential to conserve natural resources and mitigate carbon emissions. Nevertheless, the widespread adoption of RAC in the construction industry faces challenges associated with its inherent performance deficiencies, including the formation of pores and microcracks in the recycled aggregate (RA) generated during the crushing process, as well as the presence of dual interfacial transition zones (ITZ) within the internal structure of RAC. The incorporation of fibres as reinforcement offers a promising solution to improve the performance of RAC. The paper begins with a comprehensive examination of various fibre properties and recycled aggregates. Then, summarizing the impact of fibres on RAC's performance. Special emphasis is placed on analyzing the influence of mixed fibres on the mechanical properties of RAC. The introduction of a blend of low-strength and high-strength fibres demonstrates the potential for further improving the mechanical properties of RAC beyond the benefits offered by individual fibres. This blending strategy also enhances the multiscale crack resistance of RAC, attributed to the collaborative effects of various fibres at different load stages. The reinforcing mechanism at the micro-scale of RAC is also discussed. Finally, the paper outlines perspectives for future research. [Display omitted] • A comprehensive review of hybrid fibre reinforced recycled aggregate concrete. • The effects of a single type of fibre on mechanical properties and microstructure. • Combining high-strength and low-strength fibres shows positive effects. • Blended fibres induce a dense C-S-H gel phase, enhancing cracking resistance. • The economic and environmental impacts are discussed. [ABSTRACT FROM AUTHOR]

This work presents the results of archaeobotanical examinations of fragments of monumental terracruda sculptures from the Buddhist sites of Tepe Narenj and Qol-e-tut (Kabul, Afghanistan—5th to eleventh centuries CE). The results indicate that different plants and parts of plants were intentionally added to the clay mixtures. In particular, we identified an extensive presence of bast fibres, which were not evidenced by macroscopic examinations and previous analyses. Among the fibres, we highlight the presence of ramie/nettle, whose use has been identified for the first time in this type of artworks. The determination of these herbaceous additives offer a new perspective for studying the manufacturing technique, as well as an anchor point to follow this tradition along the Silk Roads. It also provides relevant information that should be taken into account in the design of conservative interventions adapted to the specific nature of this heritage. [ABSTRACT FROM AUTHOR]

Summary: The current research paper presents an investigation of the piezoelectric performances of five different polyvinylidene fluoride hexafluoropropylene (PHP) systems fabricated by electrospinning. Morphological and structural analyses of neat PHP, PHP/zinc oxide 1% (PHP‐Z), PHP/mesoporous silica 1% (PHP‐M), PHP/ZnO‐mesoporous silica at 1 wt.% (PHP‐MZ1), and PHP/ZnO‐mesoporous silica at 3 wt% (PHP‐MZ3) were carried out systematically by scanning electron microscopy, transmission electron microscope, energy‐dispersive X‐ray spectroscopy (EDX), and X‐ray diffraction (XRD). The microscopic analysis results show the formation of uniform ZnO nanoflakes of approximately 5 nm in diameter, whereas mesoporous silica particles form a uniform spherical structure with a typical diameter of 5 μm. Elemental analysis by EDX spectra confirms the presence of Zn, O, and Si in the prepared nanocomposites. The crystalline β‐phase of PHP in the Fourier transformation infrared spectra rises with the addition of ZnO and mesoporous silica particles to the polymer matrix. Neat polyvinylidene fluoride has the most intense XRD peak in comparison to all other polymer nanocomposites. The fabricated flexible nanogenerator obtained from the 1% ZnO‐mesoporous silica nanocomposite shows an output voltage of 2 V, whereas the nanogenerator prepared using the neat PHP sample exhibits an output voltage of ~120 mV. All of the results indicate that the 1% ZnO‐mesoporous silica PHP nanocomposite is suitable for constructing low‐powered wearable self‐driven electrical devices. [ABSTRACT FROM AUTHOR]

Stainless-steel fibre hybrid spun yarns are becoming increasingly popular due to their wide range of applications. In this aspect, the cost-effective and scalable processing of such yarns is highly important. Stainless-steel staple fibres are relatively heavier and weaker compared to conventional textile fibres. As a result, the staple spinning processing of these fibres showing higher tensile strength and productivity both at the same time is quite challenging. In this manuscript, we explored a number of spinning techniques to find the optimised method of producing low-twist and high-strength stainless-steel fibre hybrid spun yarns offering the advantage of both quality and productivity. Conventional ring spinning, folding and twisting, and advanced ring spinning techniques (ARSTs) such as pneumatic compact ring spinning and pneumatic compact SIRO spinning were employed in this study. Additionally, the plain and SIRO yarns were produced in two forms using the compact spinning method, one with pneumatic suction active (compact plain, compact SIRO) and other with pneumatic suction inactive (noncompact plain, noncompact SIRO). The tensile properties of yarns were tested and analysed. The results reveal that the tensile properties of conventional ring-spun and plied yarns can be enhanced to some extent by increasing the twist coefficient (TC) and the number of yarn plies, respectively. In contrast, by finding optimised spinning parameters, a substantially higher tensile strength (up to 16%) of yarns, produced at ARSTs, was observed even at the minimum level of TC used in experiments. The findings of the study are extremely valuable in terms of scaling up the production of high-quality metallic fibre hybrid spun yarns at a higher productivity level. [ABSTRACT FROM AUTHOR]

Fibres have long been utilized in the construction sector to improve the mechanical qualities of structural elements such as beams, columns, and slabs. This study aims to review the torsional behaviour of various forms of fibre reinforced concrete to identify possible enhancements and the practicability of concrete structural beams. Concrete reinforced steel fibre, synthetic fibre, and hybrid fibre are examples of fibre reinforced concrete. The review found that the mixing, orientation, and volume of fibres, the size of coarse particles, the aspect ratio of fibres, and the stiffness of fibres all affect the torsional strength of fibre reinforced concrete. Nevertheless, the application of fibres to recycled self-consolidating concrete of various forms needs to be explored and studied to ascertain its feasibility to facilitate greener concrete. Thus, with the results compiled in this review paper, it was possible to delimit advances and gaps on the effect of editing reinforcement fibres in relation to the torsion of structural elements. [ABSTRACT FROM AUTHOR]

Polymeric materials reinforced with synthetic fibres such as glass, carbon, and aramid provide advantages of high stiffness and strength to weight ratio as compared to conventional construction materials, i.e., wood, concrete, and steel. Despite these advantages, the widespread use of synthetic fibre-reinforced polymer composite tends to decline because of their high-initial costs, their use in non-efficient structural forms, and, most importantly, their adverse environmental impact. The banana fibres were chemically modified through contact with 10 wt % sodium hydroxide solutions for 45 minutes. Polymeric composites with different fibre lengths were prepared through the hand lay-up process at room temperature. Prepared composites exhibited better mechanical and thermal properties. The tensile strength increased with an increasing fibre length of the banana fibre in epoxy matrix composites, due to the stronger interfacial interactions between the treated fibres and the epoxy matrix. These effects occurred due to the morphological and chemical changes in the treated fibre surfaces, which promote better adhesion between the fibres and the epoxy matrix. [ABSTRACT FROM AUTHOR]

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Reinforced concrete structures exposed to high temperatures may significantly reduce the characteristics of concrete in terms of strength, plastic deformation of reinforced steel bar and most precisely, the bond between the concrete and the reinforcing steel. Since there are only limited literature available in the field of concrete reinforced with hybrid fibres, which contain natural fibres subjected to elevated temperature, a thorough investigation needs to be done in this area. Hence, this investigation was carried out to evaluate the strength properties of concrete after adding different types of fibres under normal and elevated temperature conditions (27°C, 200°C, 400°C and 800°C). Micro steel, polypropylene and sisal fibres were used monolithically and in hybrid form with a volume fraction of 1%. The fresh property of the mixes was evaluated by conducting slump cone test, and the hardened properties were evaluated by density, compressive strength and split tensile strength tests. In addition, the bond between the concrete and the reinforcing bar was evaluated, and the residual properties were compared with the control mix. The results reveal that in elevated temperature conditions, the inclusion of micro steel fibres has a significant role in enhancing concrete strength and bond characteristics. The addition of polypropylene and sisal fibres mainly helps prevent spalling and has a slight effect on the bond characteristics of concrete compared to that of the control specimen subjected to elevated temperature. [ABSTRACT FROM AUTHOR]

In this study, nanoscale composite SiC-ZrC ceramic fibres, derived from polyzirconocenecarbosilane (PZCS) via melt spinning, electron beam crosslinking, pyrolysis and sintering were investigated in detail. Compared with several commercial products of second-generation SiC fibres, the produced composite fibres exhibit improved thermal stability, mechanical properties and oxidation resistance. SiC grains in the fibre grew from 9.8 nm to 33.9 nm after annealing in an inert atmosphere at 1800 °C for 1 h, as well as decomposition of the SiC x O y phase and the growth of SiC grains affected the mechanical properties of the fibres, and the mechanical properties of the fibres were maintained at 1.1 GPa, accompanied by an increase in the modulus. After the fibres were oxidized at 1100∼1400 °C for 1 h, a dense oxide layer of SiO 2 -ZrO 2 was formed on the surface of the fibres, which slowed down the rate of further fibre oxidation, thus, the fibres exhibited excellent oxidation resistance. [ABSTRACT FROM AUTHOR]

Pullulan was used as the wall material for microencapsulation of L. plantarum CRD7 by spray drying, while isomalto-oligosaccharides (IMO) was used as prebiotic. Also, the effect of different thermal protectants on survival rate during microencapsulation was evaluated. Taguchi orthogonal array design showed that pullulan at 14 % concentration, IMO at 30 % concentration and whey protein isolate at 20 % rate were the optimized wall material, prebiotic and thermal protectant, respectively for microencapsulation of L. plantarum. FESEM images revealed that the spray-dried encapsulates were fibrous similar to those produce by electrospinning, while fluorescence microscopy ascertained that most of the probiotic cells were alive and intact after microencapsulation. The adsorption-desorption isotherm was of Type II and the encapsulate had specific surface area of 1.92 m2/g and mean pore diameter of 15.12 nm. The typical amide II and III bands of the bacterial proteins were absent in the FTIR spectra, suggestive of adequate encapsulation. DSC thermogram showed shifting of melting peaks to wider temperature range due to interactions between the probiotic and wall materials. IMO at 30 % (w /w) along with WPI at 20 % concentration provided the highest storage stability and the lowest rate of cell death of L. plantarum after microencapsulation. Acid and bile salt tolerance results confirmed that microencapsulated L. plantarum could sustain the harsh GI conditions with >7.5 log CFU/g viability. After microencapsulation, L. plantarum also possessed the ability to ferment milk into curd with pH of 4.62. [ABSTRACT FROM AUTHOR]

Featured Application: Electrically conductive low-cost fillers/fibres can be added to mortars/concretes to manufacture self-sensing structural elements. Structural health monitoring to assess the safety, durability and performance of structures can be performed by non-destructive methods such as the measurement of impedance in self-sensing cement-based elements. Cement-based materials, like mortars and concretes, generally have high electrical resistivity but the addition of carbon-based fillers and fibres decreases their electrical resistivity and thus enhances their self-sensing capabilities. In this study, two waste carbon-based fillers, namely, used foundry sand and gasification char were compared to commercial graphene nanoplatelets and used to produce self-sensing cement mortars, both with and without recycled or virgin carbon fibres. The mortars were tested in terms of their mechanical and electrical properties as well as their propensity to capillary water absorption. The results demonstrate that gasification char alone is the best carbonaceous waste for decreasing the electrical resistivity (−42%) and water absorption (−17%) of mortars, while their compressive strength remains unaltered. Moreover, although there is a slight reduction in compressive strength and an increase in water suction when gasification char is coupled with fibres, the combination of fillers and fibres has a synergistic effect in decreasing mortars' electrical resistivity, especially when recycled carbon fibres are used (−80%). [ABSTRACT FROM AUTHOR]

Synthetic vascular grafting is necessarily when the autografting is not possible in some cases. Conventional polyethylene terephthalate and expanded polytetrafluoroethylene vascular grafts are found to be effective for diameter bigger than 6 mm but not for the diameter smaller than 4 mm due to the compliance mismatch and thrombogenicity. Endothelization on the surface of the graft can reduce the risks of compliance mismatch and thrombogenicity. In order to catalyst the endothelization process, fibrous morphology similar to the extracellular matrix of our body is preferable in the vascular grafts. Apart from that, the biostability of the grafts is also an essential element to be considered as the biodegradation may reduce the efficiency of the grafts. Many polyurethanes have been recognised as biostable materials. Hence, in this study, highly aligned polyurethane fibres are fabricated using a facile dry spinning technique in the view of providing effective sites for endothelization process to occur. These fibres are immersed into the simulated body fluid for as long as 24 weeks before conducting the biostability characterisations. The biostability is assessed in three aspects, physical, mechanical and chemical properties. Results show that the fibres do not have observable or significant deteriorations in all the three aspects mentioned. [ABSTRACT FROM AUTHOR]

The fragmentation of small, brittle, flexible, inextensible fibres is investigated in a fully developed, homogeneous, isotropic turbulent flow. Such small fibres spend most of their time fully stretched and their dynamics follows that of stiff rods. They can then break through tensile failure, i.e. when the tension is higher than a given threshold. Fibres bend when experiencing a strong compression. During these rare and intermittent buckling events, they can break under flexural failure, i.e. when the curvature exceeds a threshold. Fine-scale massive simulations of both the fluid flow and the fibre dynamics are performed to provide statistics on these two fragmentation processes. This gives ingredients for the development of accurate macroscopic models, namely the fragmentation rate and daughter-size distributions, which can be used to predict the time evolution of the fibre size distribution. Evidence is provided for the generic nature of turbulent fragmentation and of the resulting population dynamics. It is indeed shown that the statistics of break-up is fully determined by the probability distribution of Lagrangian fluid velocity gradients. This approach singles out that the only relevant dimensionless parameter is a local flexibility which balances flow stretching to the fibre elastic forces. This article is part of the theme issue 'Fluid dynamics, soft matter and complex systems: recent results and new methods'. [ABSTRACT FROM AUTHOR]

Summary: Soluble dietary fibres from sugarcane bagasse were extracted under alkaline conditions and characterised. Precipitated fibres were dialysed, and the fibre composition was evaluated before and after the dialysis step. Compositional analysis indicated that the fibres both before and after dialysis consisted of 39% w/w total sugars, 16% w/w protein, 10% w/w Klason lignin and 30% w/w ash. Xylose was the main neutral sugar followed by arabinose with glucose, galactose and uronic acids also present in all samples. The structural properties were also spectroscopically examined, which confirmed the presence of arabinoxylans. Macromolecular characterisation revealed that molecular weight is reduced after dialysis, indicating that a range of dietary fibres with different macromolecular characteristics may be obtained depending on the specific processing steps. The present work shows that soluble arabinoxylans may be obtained from sugarcane agricultural wastes that may be used as a source of novel dietary fibres. [ABSTRACT FROM AUTHOR]

The influences of fibres originating from different waste materials on the fresh and hardened properties of self-compacting concrete (SCC) were investigated in this study. For this purpose, a total number of 13 mixes of wood (WF), polyvinyl chloride (PF), aluminium (AF), and iron filing (IF) fibres, with volume fractions (Vf) of 0.5%, 1.0%, and 1.5% were prepared. The investigated fresh properties of the prepared mixes were slump flow, T500, V-funnel as well as L-box tests, while the hardened properties were compressive strength, flexural strength, and ultrasonic pulse velocity (UPV). The findings indicated that although the majority of the prepared SCC mixes met the required self-compacting criteria, the inclusion of the waste fibres negatively affected the mix workability, particularly when Vf of 1.5% was used. Regarding the hardened properties, SCC mixes-containing IF exhibited a slight increase in both compressive and flexural strength compared with the reference mix without fibres, whereas mixes with AF fibres demonstrated a noticeable decrease in compressive strength, but with a comparable level of flexural strength. However, the flexural strength of WF and PF decreased as their Vf increased in the SCC mixes, although a slight increase in compressive strength was noted in the mixes with PF. Furthermore, there was no reliable relationship to be constructed between the compressive strength and UPV tests for all fibres used. [ABSTRACT FROM AUTHOR]

The purpose of this work was to develop implantable Doxorubicin (DOX)-incorporated into biodegradable monomethoxy poly(ethylene glycol)-poly(ε-caprolactone)-hydroxyapatite (MPEG-PCL-HA) fibres for drug delivery system in situ. In this paper, MPEG-PCL-HA nanoparticles (NPs) was prepared by surface grafting reaction of ε-caprolactone and MPEG. The obtained MPEG-PCL-HA NPs were characterised by 1H-NMR, FT-IR, XRD and TEM. Three-dimensional (3-D) porous fibres based on DOX loaded into MPEG-PCL-HA NPs were prepared by electrospinning method. The surface morphology of the composite fibres were investigated by SEM, which showed that the average fibre diameter decreased from about 3.4 µm to 2.1 µm. In vitro release behaviour of doxorubicin from the fibre mats was also studied in detail. The cytotoxicity of DOX/MPEG-PCL-HA fibres was evaluated by MTT assay in human breast cancer cell line (MCF-7). The experimental results strongly suggested that DOX/MPEG-PCL-HA composite fibres might have great potential application in drug delivery, especially postoperative local chemotherapy. [ABSTRACT FROM AUTHOR]

Direct shear strength have been studied on conventional concrete and ternary blend fibre reinforced geopolymer concrete. Earlier studies indicate that when fibres are added to concrete, it enhances direct shear strength and contribute to a reduction in spacing and width of cracks. Studies on direct shear strength of Ternary blend Geopolymer Concrete (TGPC) has not been investigated. Also, the effects on the addition of fibres on TGPC is not yet studied. The paper is intended to provide a basic understanding of the direct shear behaviour of TGPC reinforced with steel fibers. This paper presents the results of the use of Fly Ash (FA), Ground Granulated Blast Furnace Slag (GGBS) and Rice Husk Ash (RHA) as a ternary blend source material in Geopolymer Concrete (GPC). The study is limited to TGPC with 0.25%, 0.5%, 0.75% and 1% volume fraction of fibres. Push off specimen was used for studying the direct shear behaviour. It was found that fibre addition upto 1% delayed the crack propagation and showed better performance in the ultimate direct shear capacity and toughness than the conventional concrete specimens. [ABSTRACT FROM AUTHOR]

Sized glass fibre bundles were treated using atmospheric pressure plasma in a helium/tetrafluoromethane gas mixture. X-ray photoelectron spectroscopy showed that fluorine was introduced onto the sizing surface. A new analysis method (dynamic micro-wetting) to determine the wetting rate of the plasma-treated fibre bundles is presented. The dynamic micro-wetting test using glycerol as a test liquid showed a reduced wetting rate after plasma treatment. It is demonstrated that dynamic micro-wetting is a useful tool for the characterization of fibre bundle wetting. [ABSTRACT FROM AUTHOR]

The content of the review covers, first, generalities on creep. Then, the creep of ceramics and fibres, that are key constituents of fibre-reinforced ceramic matrix composites (CMCs) are addressed. The general features of ceramic matrix composites that may influence the creep behaviour and creep rupture are discussed. Emphasis is placed on microstructure–property relationships and load sharing between fibres and matrix that are critical for CMCs. Then, creep tests and the creep behaviour of various types of fibre-reinforced composites are presented. Mechanisms and models are discussed. The influence of various factors including composite structure, constituent properties (matrix and fibres), interfacial properties and environmental conditions are examined. The paper focuses on non-oxide composites like SiC/SiC that received much attention during the last three decades. Creep of oxide ceramics, fibres and composites are addressed more briefly. [ABSTRACT FROM AUTHOR]

Sized glass fibre bundles were treated using atmospheric pressure plasma in a helium/tetrafluoromethane gas mixture. X-ray photoelectron spectroscopy showed that fluorine was introduced onto the sizing surface. A new analysis method (dynamic micro-wetting) to determine the wetting rate of the plasma-treated fibre bundles is presented. The dynamic micro-wetting test using glycerol as a test liquid showed a reduced wetting rate after plasma treatment. It is demonstrated that dynamic micro-wetting is a useful tool for the characterization of fibre bundle wetting. [ABSTRACT FROM AUTHOR]